rfc8881xml2.original.xml		rfc8881.xml
	<?xml version="1.0" encoding="US-ASCII"?>		<?xml version='1.0' encoding='utf-8'?>
	<!DOCTYPE rfc SYSTEM "rfc2629.dtd">		<!DOCTYPE rfc SYSTEM "rfc2629-xhtml.ent">
	<?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?>		<rfc xmlns:xi="http://www.w3.org/2001/XInclude" category="std" docName="draft-ie
			tf-nfsv4-rfc5661sesqui-msns-04" number="8881" obsoletes="5661" ipr="pre5378Trust
	<?rfc toc="yes"?>		200902" updates="" submissionType="IETF" consensus="true" xml:lang="en" tocInclu
	<?rfc tocompact="yes"?>		de="true" tocDepth="2" symRefs="false" sortRefs="false" version="3">
	<?rfc tocdepth="2"?>
	<?rfc symrefs="no"?>
	<?rfc sortrefs="no" ?>
	<?rfc compact="yes" ?>
	<?rfc subcompact="no" ?>
	<?rfc rfcedstyle="yes" ?>
	<rfc
	category="std"
	docName="draft-ietf-nfsv4-rfc5661sesqui-msns-04"
	obsoletes="5661"
	ipr="pre5378Trust200902">
	<front>		<!-- xml2rfc v2v3 conversion 2.41.0 -->
	<title abbrev="NFSv4.1 with Namespace Update ">		<front>
			<title abbrev="NFSv4.1 with Namespace Update ">
	Network File System (NFS) Version 4 Minor Version 1 Protocol		Network File System (NFS) Version 4 Minor Version 1 Protocol
	</title>		</title>
			<seriesInfo name="RFC" value="8881"/>
	<author fullname="David Noveck"		<author fullname="David Noveck" initials="D." surname="Noveck" role="editor"
	initials="D."		>
	surname="Noveck" role="editor">		<organization abbrev="NetApp">NetApp</organization>
	<organization abbrev="NetApp">NetApp</organization>		<address>
	<address>		<postal>
	<postal>		<street>1601 Trapelo Road, Suite 16</street>
	<street>1601 Trapelo Road, Suite 16</street>		<city>Waltham</city>
	<city>Waltham</city>		<region>MA</region>
	<region>MA</region>		<code>02451</code>
	<code>02451</code>		<country>United States of America</country>
	<country>USA</country>		</postal>
	</postal>		<phone>+1-781-768-5347</phone>
	<phone>+1-781-768-5347</phone>		<email>dnoveck@netapp.com</email>
	<email>dnoveck@netapp.com</email>		</address>
	</address>
	</author>		</author>
	<author initials='C.' surname='Lever'		<author initials="C." surname="Lever" fullname="Charles Lever">
	fullname = 'Charles Lever'>		<organization abbrev="ORACLE">
	<organization abbrev='ORACLE'>
	Oracle Corporation		Oracle Corporation
	</organization>		</organization>
	<address>		<address>
	<postal>		<postal>
	<street>1015 Granger Avenue</street>		<street>1015 Granger Avenue</street>
	<city>Ann Arbor</city>		<city>Ann Arbor</city>
	<region>MI</region>		<region>MI</region>
	<code>48104</code>		<code>48104</code>
	<country>United States of America</country>		<country>United States of America</country>
	</postal>		</postal>
			<phone>+1-248-614-5091</phone>
	<phone>+1 248 614 5091</phone>
	<email>chuck.lever@oracle.com</email>		<email>chuck.lever@oracle.com</email>
	</address>		</address>
	</author>		</author>
			<date month="August" year="2020"/>
	<date year="2020"/>
	<area>Transport</area>		<area>Transport</area>
	<workgroup>NFSv4</workgroup>		<workgroup>NFSv4</workgroup>
			<keyword>example</keyword>
	<abstract>		<abstract>
	<t>		<t>
	This document describes the Network File System (NFS) version 4		This document describes the Network File System (NFS) version 4
	minor version 1,		minor version 1,
	including features retained from the base protocol (NFS version 4 minor		including features retained from the base protocol (NFS version 4 minor
	version 0, which is specified in RFC 7530) and protocol		version 0, which is specified in RFC 7530) and protocol
	extensions made subsequently. The later minor version		extensions made subsequently. The later minor version
	has no dependencies on NFS version 4 minor version 0, and		has no dependencies on NFS version 4 minor version 0, and
	is considered a separate protocol.		is considered a separate protocol.
	</t>		</t>
	<t>		<t>
	This document obsoletes RFC5661. It substantially revises the treatment		This document obsoletes RFC 5661. It substantially revises the treatment
	of features relating to multi-server namespace, superseding the		of features relating to multi-server namespace, superseding the
	description of those features appearing in RFC5661.		description of those features appearing in RFC 5661.
	</t>		</t>
	</abstract>		</abstract>
			</front>
	</front>		<middle>
			<section anchor="intro" numbered="true" toc="default">
	<middle>		<name>Introduction</name>
			<section anchor="intro_the_document" numbered="true" toc="default">
	<section anchor="intro" title="Introduction" >		<name>Introduction to This Update</name>
	<section anchor="intro_the_document"		<t>
	title="Introduction to this Update">
	<t>
	Two important features previously defined in minor version 0 but		Two important features previously defined in minor version 0 but
	never fully addressed in minor version 1 are trunking, the		never fully addressed in minor version 1 are trunking, which is the
	simultaneous use of		simultaneous use of
	multiple connections between a client and server, potentially to		multiple connections between a client and server, potentially to
	different network addresses, and transparent state migration, which		different network addresses, and Transparent State Migration, which
	allows a file system to be transferred between servers in a way that		allows a file system to be transferred between servers in a way that
	provides to the client the ability to maintain its existing locking		provides to the client the ability to maintain its existing locking
	state across the transfer.		state across the transfer.
	</t>		</t>
	<t>		<t>
	The revised description of the NFS version 4 minor version 1		The revised description of the NFS version 4 minor version 1
	(NFSv4.1) protocol presented in this update is necessary to enable		(NFSv4.1) protocol presented in this update is necessary to enable
	full use of these features together with other multi-server namespace		full use of these features together with other multi-server namespace
	features. This document is in the form of an updated description of		features. This document is in the form of an updated description of
	the NFSv4.1 protocol previously defined in RFC5661		the NFSv4.1 protocol previously defined in RFC 5661
	<xref target="RFC5661"/>.		<xref target="RFC5661" format="default"/>.
	RFC5661 is obsoleted by this document. However, the update has a		RFC 5661 is obsoleted by this document. However, the update has a
	limited scope and is focused on enabling full use of trunking and		limited scope and is focused on enabling full use of trunking and
	transparent state migration. The need for these changes is discussed		Transparent State Migration. The need for these changes is discussed
	in Appendix A. Appendix B describes the specific changes made to		in <xref target="NEED"/>. <xref target="CHG"/> describes the specific cha
			nges made to
	arrive at the current text.		arrive at the current text.
	</t>		</t>
	<t>		<t>
	This limited-scope update replaces the current NFSv4.1 RFC with the		This limited-scope update replaces the current NFSv4.1 RFC with the
	intention of providing an authoritative and complete specification, the		intention of providing an authoritative and complete specification, the
	motivation for which is discussed in		motivation for which is discussed in
	<xref target="I-D.roach-bis-documents"/>,		<xref target="I-D.roach-bis-documents" format="default"/>,
	addressing the issues within the scope of the update. However, it will		addressing the issues within the scope of the update. However, it will
	not address issues that are known but outside of this limited scope		not address issues that are known but outside of this limited scope
	as could expected by a full update of the protocol. Below are some		as could be expected by a full update of the protocol. Below are some
	areas which are known to need addressing in a future update of the		areas that are known to need addressing in a future update of the
	protocol.		protocol:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	Work needs to be done with regard to		<li>
	RFC8178 <xref target="RFC8178"/> which establishes NFSv4-wide		Work needs to be done with regard to RFC 8178
			<xref target="RFC8178" format="default"/>, which establishes NFSv4-wide
	versioning rules. As		versioning rules. As
	RFC5661 is currently inconsistent with		RFC 5661 is currently inconsistent with
	that document, changes are needed in order		that document, changes are needed in order
	to arrive at a situation in which there		to arrive at a situation in which there
	would be no need for RFC8178 to update the NFSv4.1 specification.		would be no need for RFC 8178 to update the NFSv4.1 specification.
	</t>		</li>
	<t>		<li>
	Work needs to be done with regard to		Work needs to be done with regard to RFC 8434
	RFC8434 <xref target="RFC8434" />, which establishes the requirements		<xref target="RFC8434" format="default"/>, which establishes the requirem
	for pNFS layout types, which are not clearly defined in		ents
	RFC5661. When that		for parallel NFS (pNFS) layout types, which are not clearly defined in
			RFC 5661. When that
	work is done and the resulting documents approved,		work is done and the resulting documents approved,
	the new NFSv4.1 specification document will provide a clear set		the new NFSv4.1 specification document will provide a clear set
	of requirements for layout types and a description of the file layout		of requirements for layout types and a description of the file layout
	type that conforms to those requirements. Other layout types will		type that conforms to those requirements. Other layout types will
	have their own specification documents that conforms to those		have their own specification documents that conform to those
	requirements as well.		requirements as well.
	</t>		</li>
	<t>		<li>
			<t>
	Work needs to be done to address many errata reports relevant to		Work needs to be done to address many errata reports relevant to
	RFC 5661, other than errata report 2006 <xref target="Err2006"/>,		RFC 5661, other than errata report 2006 <xref target="Err2006" format="de fault"/>,
	which is addressed in this document.		which is addressed in this document.
	Addressing that report was not deferrable because of the		Addressing that report was not deferrable because of the
	interaction of the changes suggested there		interaction of the changes suggested there
	and the newly described handling of state and session migration.		and the newly described handling of state and session migration.
	<vspace blankLines="1"/>		</t>
			<t>
	The errata reports that have been deferred and that will need to		The errata reports that have been deferred and that will need to
	be addressed in a later document include reports currently assigned		be addressed in a later document include reports currently assigned
	a range of statuses in the errata reporting system including reports		a range of statuses in the errata reporting system, including reports
	marked Accepted and those marked Hold For Document Update		marked Accepted and those marked Hold For Document Update
	because the change was		because the change was
	too minor to address immediately.		too minor to address immediately.
	<vspace blankLines="1"/>		</t>
			<t>
	In addition, there is a set of other reports, including at least one		In addition, there is a set of other reports, including at least one
	in state Rejected, which will need to be addressed in a later document.		in state Rejected, that will need to be addressed in a later document.
	This will involve making changes to consensus decisions reflected		This will involve making changes to consensus decisions reflected
	in RFC 5661, in situation in which the working group has decided that		in RFC 5661, in situations in which the working group has decided that
	the treatment in RFC 5661 is incorrect, and needs to be revised to		the treatment in RFC 5661 is incorrect and needs to be revised to
	reflect the working group's new consensus and ensure compatibility		reflect the working group's new consensus and to ensure compatibility
	with existing implementations that do not follow the handling		with existing implementations that do not follow the handling
	described in		described in RFC 5661.
	in RFC 5661.		</t>
	<vspace blankLines="1"/>		<t>
	Note that it is expected that all such errata reports will remain		Note that it is expected that all such errata reports will remain
	relevant to implementers and the authors of an eventual rfc5661bis,		relevant to implementors and the authors of an eventual rfc5661bis,
	despite the fact that this document, when approved,		despite the fact that this document
	will obsolete RFC 5661 <xref target="RFC5661"/>.		obsoletes RFC 5661 <xref target="RFC5661" format="default"/>.
	</t>		</t>
	<t>		</li>
			<li>
	There is a need for a new approach to the description of		There is a need for a new approach to the description of
	internationalization since the current internationalization section		internationalization since the current internationalization section
	(<xref target="internationalization"/>) has never been		(<xref target="internationalization" format="default"/>) has never been
	implemented and does		implemented and does
	not meet the needs of the NFSv4 protocol. Possible solutions are		not meet the needs of the NFSv4 protocol. Possible solutions are
	to create a new internationalization section modeled on that in		to create a new internationalization section modeled on that in
	<xref target="RFC7530"/> or to create a new document describing		<xref target="RFC7530" format="default"/> or to create a new document des cribing
	internationalization for all		internationalization for all
	NFSv4 minor versions and reference that document in the RFCs		NFSv4 minor versions and reference that document in the RFCs
	defining both NFSv4.0 and NFSv4.1.		defining both NFSv4.0 and NFSv4.1.
	</t>		</li>
	<t>		<li>
	There is a need for a revised treatment of security		There is a need for a revised treatment of security
	in NFSv4.1. The issues with the existing treatment are discussed in		in NFSv4.1. The issues with the existing treatment are discussed in
	<xref target="SECBAD"/>.		<xref target="SECBAD" format="default"/>.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Until the above work is done, there will not be a consistent set of		Until the above work is done, there will not be a consistent set of
	documents providing a description of the NFSv4.1 protocol and any		documents that provides a description of the NFSv4.1 protocol, and any
	full description would involve documents updating other documents		full description would involve documents updating other documents
	within the specification. The updates applied by		within the specification. The updates applied by
	RFC8434 <xref target="RFC8434"/> and RFC8178 <xref target="RFC8178"/>		RFC 8434 <xref target="RFC8434" format="default"/> and RFC 8178
	to RFC5661 also apply to this specification, and will apply to		<xref target="RFC8178" format="default"/>
			to RFC 5661 also apply to this specification, and will apply to
	any subsequent v4.1 specification until that work is done.		any subsequent v4.1 specification until that work is done.
	</t>		</t>
	</section>		</section>
	<section anchor="intro_the_protocol"		<section anchor="intro_the_protocol" numbered="true" toc="default">
			<name>The NFS Version 4 Minor Version 1 Protocol</name>
	title="The NFS Version 4 Minor Version 1 Protocol">		<t>
	<t>
	The NFS version 4 minor version 1 (NFSv4.1) protocol		The NFS version 4 minor version 1 (NFSv4.1) protocol
	is the second minor version of the NFS version 4		is the second minor version of the NFS version 4
	(NFSv4) protocol. The first minor version, NFSv4.0, is		(NFSv4) protocol. The first minor version, NFSv4.0, is
	now described in RFC 7530 <xref target="RFC7530" />. It generally		now described in RFC 7530 <xref target="RFC7530" format="default"/>. It g enerally
	follows the guidelines for minor versioning that are		follows the guidelines for minor versioning that are
	listed in Section 10 of RFC 3530. However, it		listed in Section <xref target="RFC3530" sectionFormat="bare" section="10"
			/>
			of RFC 3530 <xref target="RFC3530" format="default"/>. However, it
	diverges from guidelines 11 ("a client and server		diverges from guidelines 11 ("a client and server
	that support minor version X must support minor		that support minor version X must support minor
	versions 0 through X-1") and 12 ("no new features may be		versions 0 through X-1") and 12 ("no new features may be
	introduced as mandatory in a minor version"). These		introduced as mandatory in a minor version"). These
	divergences are due to the introduction of		divergences are due to the introduction of
	the sessions model for managing non-idempotent		the sessions model for managing non-idempotent
	operations and the RECLAIM_COMPLETE operation.		operations and the RECLAIM_COMPLETE operation.
	These two new features are infrastructural in		These two new features are infrastructural in
	nature and simplify implementation of existing and		nature and simplify implementation of existing and
	other new features. Making them anything but REQUIRED		other new features. Making them anything but <bcp14>REQUIRED</bcp14>
	would add undue complexity to protocol definition and		would add undue complexity to protocol definition and
	implementation. NFSv4.1 accordingly updates the		implementation. NFSv4.1 accordingly updates the
	<xref target="minor_versioning">minor versioning		<xref target="minor_versioning" format="default">minor versioning
	guidelines</xref>.		guidelines</xref>.
	</t>		</t>
	<t>		<t>
	As a minor version, NFSv4.1 is consistent with the overall		As a minor version, NFSv4.1 is consistent with the overall
	goals for NFSv4, but extends the protocol so as to		goals for NFSv4, but extends the protocol so as to
	better meet those goals, based on experiences with NFSv4.0.		better meet those goals, based on experiences with NFSv4.0.
	In addition, NFSv4.1 has adopted some additional goals, which		In addition, NFSv4.1 has adopted some additional goals, which
	motivate some of the major extensions in NFSv4.1.		motivate some of the major extensions in NFSv4.1.
	</t>		</t>
	</section>		</section>
	<section title="Requirements Language">		<section numbered="true" toc="default">
	<t>The key words &quot;MUST&quot;, &quot;MUST NOT&quot;,		<name>Requirements Language</name>
	&quot;REQUIRED&quot;, &quot;SHALL&quot;, &quot;SHALL NOT&quot;,
	&quot;SHOULD&quot;, &quot;SHOULD NOT&quot;, &quot;RECOMMENDED&quot;,
	&quot;MAY&quot;, and &quot;OPTIONAL&quot; in this document are to be
	interpreted as described in <xref target="RFC2119">RFC 2119</xref>.
	</t>
	</section>		<t>The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14
			>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL
			NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp1
			4>RECOMMENDED</bcp14>", "<bcp14>MAY</bcp14>", and
			"<bcp14>OPTIONAL</bcp14>" in this document are to be interpreted as descri
			bed in
			RFC 2119 <xref target="RFC2119"/>.</t>
	<section anchor="scope_of_doc" title="Scope of This Document">		</section>
	<t>		<section anchor="scope_of_doc" numbered="true" toc="default">
			<name>Scope of This Document</name>
			<t>
	This document describes the NFSv4.1 protocol. With		This document describes the NFSv4.1 protocol. With
	respect to NFSv4.0, this document does not:		respect to NFSv4.0, this document does not:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	describe the NFSv4.0 protocol, except where needed		describe the NFSv4.0 protocol, except where needed
	to contrast with NFSv4.1.		to contrast with NFSv4.1.
	</t>		</li>
			<li>
	<t>
	modify the specification of the NFSv4.0 protocol.		modify the specification of the NFSv4.0 protocol.
	</t>		</li>
			<li>
	<t>
	clarify the NFSv4.0 protocol.		clarify the NFSv4.0 protocol.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
			<section anchor="version4_goals" numbered="true" toc="default">
	</section>		<name>NFSv4 Goals</name>
	<section anchor="version4_goals" title="NFSv4 Goals">		<t>
	<t>
	The NFSv4 protocol is a further revision of the NFS protocol		The NFSv4 protocol is a further revision of the NFS protocol
	defined already by NFSv3		defined already by NFSv3
	<xref target="RFC1813" />. It retains		<xref target="RFC1813" format="default"/>. It retains
	the essential characteristics of previous versions: easy		the essential characteristics of previous versions: easy
	recovery; independence of transport protocols, operating systems, and		recovery; independence of transport protocols, operating systems, and
	file systems; simplicity; and good performance. NFSv4 has the following g oals:		file systems; simplicity; and good performance. NFSv4 has the following g oals:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	Improved access and good performance on the Internet		Improved access and good performance on the Internet
	<vspace blankLines='1' />		</t>
			<t>
	The protocol is designed to transit firewalls easily, perform well		The protocol is designed to transit firewalls easily, perform well
	where latency is high and bandwidth is low, and scale to very		where latency is high and bandwidth is low, and scale to very
	large numbers of clients per server.		large numbers of clients per server.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	Strong security with negotiation built into the protocol		Strong security with negotiation built into the protocol
	<vspace blankLines='1' />		</t>
			<t>
	The protocol builds on the work of the ONCRPC working group in		The protocol builds on the work of the ONCRPC working group in
	supporting the RPCSEC_GSS protocol. Additionally, the		supporting the RPCSEC_GSS protocol. Additionally, the
	NFSv4.1 protocol provides a mechanism to allow clients and		NFSv4.1 protocol provides a mechanism to allow clients and
	servers the ability to negotiate security and require clients and server s to		servers the ability to negotiate security and require clients and server s to
	support a minimal set of security schemes.		support a minimal set of security schemes.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	Good cross-platform interoperability		Good cross-platform interoperability
	<vspace blankLines='1' />		</t>
			<t>
	The protocol features a file system model that provides a useful,		The protocol features a file system model that provides a useful,
	common set of features that does not unduly favor one file system		common set of features that does not unduly favor one file system
	or operating system over another.		or operating system over another.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	Designed for protocol extensions		Designed for protocol extensions
	<vspace blankLines='1' />		</t>
			<t>
	The protocol is designed to accept standard extensions within a		The protocol is designed to accept standard extensions within a
	framework that enables and encourages backward compatibility.		framework that enables and encourages backward compatibility.
	</t>		</t>
	</list>		</li>
	</t>		</ul>
	</section>		</section>
	<section anchor="minor_version1_goals" title="NFSv4.1 Goals">		<section anchor="minor_version1_goals" numbered="true" toc="default">
	<t>		<name>NFSv4.1 Goals</name>
			<t>
	NFSv4.1 has the following goals, within the framework		NFSv4.1 has the following goals, within the framework
	established by the overall NFSv4 goals.		established by the overall NFSv4 goals.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	To correct significant structural weaknesses and oversights		To correct significant structural weaknesses and oversights
	discovered in the base protocol.		discovered in the base protocol.
	</t>		</li>
	<t>		<li>
	To add clarity and specificity to areas left		To add clarity and specificity to areas left
	unaddressed or not addressed in sufficient		unaddressed or not addressed in sufficient
	detail in the base protocol. However, as stated		detail in the base protocol. However, as stated
	in <xref target="scope_of_doc" />, it is not		in <xref target="scope_of_doc" format="default"/>, it is not
	a goal to clarify the NFSv4.0 protocol in the		a goal to clarify the NFSv4.0 protocol in the
	NFSv4.1 specification.		NFSv4.1 specification.
	</t>		</li>
	<t>		<li>
	To add specific features based on experience with the existing		To add specific features based on experience with the existing
	protocol and recent industry developments.		protocol and recent industry developments.
	</t>		</li>
	<t>		<li>
	To provide protocol support to take advantage of clustered		To provide protocol support to take advantage of clustered
	server deployments including the ability to provide scalable		server deployments including the ability to provide scalable
	parallel access to files distributed among multiple servers.		parallel access to files distributed among multiple servers.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section anchor="intro_definitions" numbered="true" toc="default">
	<section anchor="intro_definitions" title="General Definitions">		<name>General Definitions</name>
	<t>		<t>
	The following definitions provide an appropriate context for the reader.		The following definitions provide an appropriate context for the reader.
	<list style='hanging'>		</t>
	<t hangText="Byte:" anchor="byte">		<dl newline="false" spacing="normal">
			<dt>Byte:</dt>
			<dd anchor="byte">
	In this document, a byte is an octet, i.e., a datum		In this document, a byte is an octet, i.e., a datum
	exactly 8 bits in length.		exactly 8 bits in length.
	</t>		</dd>
	<t hangText="Client:" anchor="client_def">		<dt>Client:</dt>
			<dd anchor="client_def">
			<t>
	The client is the entity that accesses the NFS server's		The client is the entity that accesses the NFS server's
	resources. The client may be an application that contains		resources. The client may be an application that contains
	the logic to access the NFS server directly. The client		the logic to access the NFS server directly. The client
	may also be the traditional operating system client that		may also be the traditional operating system client that
	provides remote file system services for a set of applications.		provides remote file system services for a set of applications.
	<vspace blankLines='1' />		</t>
			<t>
	A client is uniquely identified by a client owner.		A client is uniquely identified by a client owner.
	<vspace blankLines='1' />		</t>
			<t>
	With reference to byte-range locking, the client is also the entity th at		With reference to byte-range locking, the client is also the entity th at
	maintains a set of locks on behalf of one or more		maintains a set of locks on behalf of one or more
	applications. This client is responsible for crash or		applications. This client is responsible for crash or
	failure recovery for those locks it manages.		failure recovery for those locks it manages.
	<vspace blankLines='1' />		</t>
			<t>
	Note that multiple clients may share the same transport and		Note that multiple clients may share the same transport and
	connection and		connection and
	multiple clients may exist on the same network node.		multiple clients may exist on the same network node.
	</t>		</t>
	<t hangText="Client ID:">		</dd>
			<dt>Client ID:</dt>
			<dd>
	The client ID is a 64-bit quantity used as a unique, short-hand refere nce to		The client ID is a 64-bit quantity used as a unique, short-hand refere nce to
	a client-supplied verifier and client owner. The server is		a client-supplied verifier and client owner. The server is
	responsible for supplying the client ID.		responsible for supplying the client ID.
	</t>		</dd>
	<t hangText="Client Owner:">		<dt>Client Owner:</dt>
			<dd>
	The client owner is a unique string, opaque to the server,		The client owner is a unique string, opaque to the server,
	that identifies a client. Multiple network connections and source		that identifies a client. Multiple network connections and source
	network addresses originating from those connections may share		network addresses originating from those connections may share
	a client owner. The server is expected to treat requests		a client owner. The server is expected to treat requests
	from connections with the same client owner as coming from		from connections with the same client owner as coming from
	the same client.		the same client.
	</t>		</dd>
			<dt>File System:</dt>
	<t hangText="File System:">		<dd>
	The file system is the collection of objects on a server (as		The file system is the collection of objects on a server (as
	identified by the major identifier of a server		identified by the major identifier of a server
	owner, which is defined later in this section)		owner, which is defined later in this section)
	that share the same fsid attribute (see <xref		that share the same fsid attribute (see <xref target="attrdef_fsid" fo
	target="attrdef_fsid"/>).		rmat="default"/>).
	</t>		</dd>
	<t hangText="Lease:">		<dt>Lease:</dt>
			<dd>
			<t>
	A lease is an interval of time defined by the server for which the		A lease is an interval of time defined by the server for which the
	client is irrevocably granted locks. At the end of a		client is irrevocably granted locks. At the end of a
	lease period, locks may be revoked if the lease has not		lease period, locks may be revoked if the lease has not
	been extended. A lock must be revoked if a conflicting		been extended. A lock must be revoked if a conflicting
	lock has been granted after the lease interval.		lock has been granted after the lease interval.
	<vspace blankLines='1' />		</t>
			<t>
	A server grants a client a single lease for all state.		A server grants a client a single lease for all state.
	</t>		</t>
	<t hangText="Lock:">		</dd>
			<dt>Lock:</dt>
			<dd>
	The term "lock" is used to refer to byte-range (in UNIX environments,		The term "lock" is used to refer to byte-range (in UNIX environments,
	also known as record)		also known as record)
	locks, share reservations, delegations, or layouts unless		locks, share reservations, delegations, or layouts unless
	specifically stated otherwise.		specifically stated otherwise.
	</t>		</dd>
			<dt>Secret State Verifier (SSV):</dt>
	<t hangText="Secret State Verifier (SSV):">		<dd>
	The SSV is a unique secret key shared between a client and		The SSV is a unique secret key shared between a client and
	server. The SSV serves as the secret key for an internal (that		server. The SSV serves as the secret key for an internal (that
	is, internal to NFSv4.1) Generic Security Services (GSS)		is, internal to NFSv4.1) Generic Security Services (GSS)
	mechanism (the SSV GSS mechanism;		mechanism (the SSV GSS mechanism;
	see <xref target="ssv_mech"/>). The SSV GSS mechanism uses the		see <xref target="ssv_mech" format="default"/>). The SSV GSS mechanis m uses the
	SSV to compute message integrity code (MIC) and Wrap tokens.		SSV to compute message integrity code (MIC) and Wrap tokens.
	See <xref target="protect_state_change"/> for more details on how NFSv 4.1 uses		See <xref target="protect_state_change" format="default"/> for more de tails on how NFSv4.1 uses
	the SSV and the SSV GSS mechanism.		the SSV and the SSV GSS mechanism.
	</t>		</dd>
			<dt>Server:</dt>
	<t hangText="Server:">		<dd>
	The Server is the entity responsible for coordinating		The Server is the entity responsible for coordinating
	client access to a set of file systems and is identified by a server		client access to a set of file systems and is identified by a server
	owner. A server can span multiple network addresses.		owner. A server can span multiple network addresses.
	</t>		</dd>
	<t hangText="Server Owner:">		<dt>Server Owner:</dt>
			<dd>
	The server owner identifies the server to the client.		The server owner identifies the server to the client.
	The server owner consists of a major identifier and a minor identifier .		The server owner consists of a major identifier and a minor identifier .
	When the client has two connections each to a peer with the		When the client has two connections each to a peer with the
	same major identifier, the client assumes that both peers are		same major identifier, the client assumes that both peers are
	the same server (the server namespace is the		the same server (the server namespace is the
	same via each connection) and that		same via each connection) and that
	lock state is sharable across both connections. When each peer		lock state is shareable across both connections. When each peer
	has both the same major and minor identifiers, the client		has both the same major and minor identifiers, the client
	assumes that each connection might be associable with the same session .		assumes that each connection might be associable with the same session .
	</t>		</dd>
	<t hangText="Stable Storage:">		<dt>Stable Storage:</dt>
			<dd>
			<t>
	Stable storage is storage from which data stored by		Stable storage is storage from which data stored by
	an NFSv4.1 server can be recovered without data		an NFSv4.1 server can be recovered without data
	loss from multiple power failures (including cascading		loss from multiple power failures (including cascading
	power failures, that is, several power failures in quick		power failures, that is, several power failures in quick
	succession), operating system failures, and/or hardware		succession), operating system failures, and/or hardware
	failure of components other than the storage medium itself		failure of components other than the storage medium itself
	(such as disk, nonvolatile RAM, flash memory, etc.).		(such as disk, nonvolatile RAM, flash memory, etc.).
	<vspace blankLines='1' />		</t>
			<t>
	Some examples of stable storage that are allowable for an		Some examples of stable storage that are allowable for an
	NFS server include:		NFS server include:
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	Media commit of data; that is, the modified data has		Media commit of data; that is, the modified data has
	been successfully written to the disk media, for		been successfully written to the disk media, for
	example, the disk platter.		example, the disk platter.
	</t>		</li>
	<t>		<li>
	An immediate reply disk drive with battery-backed,		An immediate reply disk drive with battery-backed,
	on-drive intermediate storage or uninterruptible power		on-drive intermediate storage or uninterruptible power
	system (UPS).		system (UPS).
	</t>		</li>
	<t>		<li>
	Server commit of data with battery-backed intermediate		Server commit of data with battery-backed intermediate
	storage and recovery software.		storage and recovery software.
	</t>		</li>
	<t>		<li>
	Cache commit with uninterruptible power system (UPS) and		Cache commit with uninterruptible power system (UPS) and
	recovery software.		recovery software.
	</t>		</li>
	</list>		</ol>
	</t>		</dd>
	<t hangText="Stateid:">		<dt>Stateid:</dt>
			<dd>
	A stateid is a 128-bit quantity returned by a server that uniquely		A stateid is a 128-bit quantity returned by a server that uniquely
	defines the open and locking states provided by the server		defines the open and locking states provided by the server
	for a specific open-owner or lock-owner/open-owner pair		for a specific open-owner or lock-owner/open-owner pair
	for a specific file and type of lock.		for a specific file and type of lock.
	</t>		</dd>
	<t hangText="Verifier:">		<dt>Verifier:</dt>
			<dd>
	A verifier is a 64-bit quantity generated by the client that the serve r		A verifier is a 64-bit quantity generated by the client that the serve r
	can use to determine if the client has restarted and lost		can use to determine if the client has restarted and lost
	all previous lock state.		all previous lock state.
	</t>		</dd>
	</list>		</dl>
	</t>		</section>
	</section>		<section anchor="feature-overview" numbered="true" toc="default">
	<section anchor="feature-overview"		<name>Overview of NFSv4.1 Features</name>
	title="Overview of NFSv4.1 Features">		<t>
	<t>
	The major features of		The major features of
	the NFSv4.1 protocol will be reviewed in brief. This will be done		the NFSv4.1 protocol will be reviewed in brief. This will be done
	to provide an appropriate context for both the reader who is familiar		to provide an appropriate context for both the reader who is familiar
	with the previous versions of the NFS protocol and the reader		with the previous versions of the NFS protocol and the reader
	who is new to the NFS protocols. For the reader new to the NFS protocols,		who is new to the NFS protocols. For the reader new to the NFS protocols,
	there is still a set of fundamental knowledge that is expected.		there is still a set of fundamental knowledge that is expected.
	The reader should be familiar with the External Data		The reader should be familiar with the External Data
	Representation (XDR) and Remote Procedure Call (RPC) protocols		Representation (XDR) and Remote Procedure Call (RPC) protocols
	as described in <xref target="RFC4506" /> and <xref target="RFC5531" />.		as described in <xref target="RFC4506" format="default"/> and <xref target ="RFC5531" format="default"/>.
	A basic knowledge of file systems and distributed file systems is expected as well.		A basic knowledge of file systems and distributed file systems is expected as well.
	</t>		</t>
	<t>		<t>
	In general, this specification of NFSv4.1 will		In general, this specification of NFSv4.1 will
	not distinguish those features added in minor version		not distinguish those features added in minor version
	1 from those present in the base protocol but		1 from those present in the base protocol but
	will treat NFSv4.1 as a unified whole. See <xref		will treat NFSv4.1 as a unified whole. See <xref target="intro_difference
	target="intro_differences" /> for a summary of		s" format="default"/> for a summary of
	the differences between NFSv4.0 and NFSv4.1.		the differences between NFSv4.0 and NFSv4.1.
	</t>		</t>
	<section anchor="rpc_and_security" title="RPC and Security">		<section anchor="rpc_and_security" numbered="true" toc="default">
	<t>		<name>RPC and Security</name>
			<t>
	As with previous versions of NFS, the External Data Representation		As with previous versions of NFS, the External Data Representation
	(XDR) and Remote Procedure Call (RPC) mechanisms used for the NFSv4.1 pr otocol are those defined in		(XDR) and Remote Procedure Call (RPC) mechanisms used for the NFSv4.1 pr otocol are those defined in
	<xref target="RFC4506" /> and <xref target="RFC5531" />. To		<xref target="RFC4506" format="default"/> and <xref target="RFC5531" for mat="default"/>. To
	meet end-to-end security requirements, the RPCSEC_GSS framework		meet end-to-end security requirements, the RPCSEC_GSS framework
	<xref target="RFC2203" /> is used to extend the basic		<xref target="RFC2203" format="default"/> is used to extend the basic
	RPC security. With the		RPC security. With the
	use of RPCSEC_GSS, various mechanisms can be provided to offer		use of RPCSEC_GSS, various mechanisms can be provided to offer
	authentication, integrity, and privacy to the NFSv4 protocol.		authentication, integrity, and privacy to the NFSv4 protocol.
	Kerberos V5 is used as described in		Kerberos V5 is used as described in
	<xref target="RFC4121" /> to provide one		<xref target="RFC4121" format="default"/> to provide one
	security framework.		security framework.
	With the use of		With the use of
	RPCSEC_GSS, other mechanisms may also be specified and used for NFSv4.1 security.		RPCSEC_GSS, other mechanisms may also be specified and used for NFSv4.1 security.
	</t>		</t>
	<t>		<t>
	To enable in-band security negotiation, the NFSv4.1 protocol		To enable in-band security negotiation, the NFSv4.1 protocol
	has operations that provide the client a method of		has operations that provide the client a method of
	querying the server about its policies regarding which security		querying the server about its policies regarding which security
	mechanisms must be used for access to the server's file system		mechanisms must be used for access to the server's file system
	resources. With this, the client can securely match the security		resources. With this, the client can securely match the security
	mechanism that meets the policies specified at both the client and		mechanism that meets the policies specified at both the client and
	server.		server.
	</t>		</t>
	<t>		<t>
	NFSv4.1 introduces parallel access (see <xref		NFSv4.1 introduces parallel access (see <xref target="parallel_access" fo
	target="parallel_access"/>), which is		rmat="default"/>), which is
	called pNFS.		called pNFS.
	The security framework		The security framework
	described in this section is		described in this section is
	significantly modified by the		significantly modified by the
	introduction of pNFS (see <xref		introduction of pNFS (see <xref target="security_considerations_pnfs" for
	target="security_considerations_pnfs"/>),		mat="default"/>),
	because data access is sometimes not over		because data access is sometimes not over
	RPC. The level of significance varies		RPC. The level of significance varies
	with the storage protocol (see <xref		with the storage protocol (see <xref target="storage_protocol" format="de
	target="storage_protocol"/>) and can be as low as zero		fault"/>) and can be as low as zero
	impact (see <xref target="file_security_considerations"/>).		impact (see <xref target="file_security_considerations" format="default"
			/>).
	</t>		</t>
	</section>		</section>
	<section anchor="protocol_structure"		<section anchor="protocol_structure" numbered="true" toc="default">
	title="Protocol Structure">		<name>Protocol Structure</name>
	<section anchor="core_protocol"		<section anchor="core_protocol" numbered="true" toc="default">
	title="Core Protocol">		<name>Core Protocol</name>
	<t>		<t>
	Unlike NFSv3, which used a series of ancillary		Unlike NFSv3, which used a series of ancillary
	protocols (e.g., NLM, NSM (Network Status Monitor), MOUNT), within all minor versions		protocols (e.g., NLM, NSM (Network Status Monitor), MOUNT), within all minor versions
	of NFSv4 a single RPC protocol is used to make requests to		of NFSv4 a single RPC protocol is used to make requests to
	the server.		the server.
	Facilities that had been separate protocols, such		Facilities that had been separate protocols, such
	as locking, are now integrated within a single unified		as locking, are now integrated within a single unified
	protocol.		protocol.
	</t>		</t>
	</section>		</section>
	<section anchor="parallel_access"		<section anchor="parallel_access" numbered="true" toc="default">
	title="Parallel Access">		<name>Parallel Access</name>
	<t>		<t>
	Minor version 1 supports high-performance data access to a		Minor version 1 supports high-performance data access to a
	clustered server implementation by enabling a separation of		clustered server implementation by enabling a separation of
	metadata access and data access, with the latter done to		metadata access and data access, with the latter done to
	multiple servers in parallel.		multiple servers in parallel.
	</t>		</t>
	<t>		<t>
	Such parallel data access is controlled by recallable		Such parallel data access is controlled by recallable
	objects known as "layouts", which are integrated into the		objects known as "layouts", which are integrated into the
	protocol locking model. Clients direct requests for		protocol locking model. Clients direct requests for
	data access to a set of data servers specified by the		data access to a set of data servers specified by the
	layout via a data		layout via a data
	storage protocol which may be NFSv4.1 or may be another		storage protocol which may be NFSv4.1 or may be another
	protocol.		protocol.
	</t>		</t>
			<t>
	<t>
	Because the protocols used for parallel		Because the protocols used for parallel
	data access are not necessarily		data access are not necessarily
	RPC-based, the RPC-based security model		RPC-based, the RPC-based security model
	(<xref target="rpc_and_security"/>) is		(<xref target="rpc_and_security" format="default"/>) is
	obviously impacted (see <xref		obviously impacted (see <xref target="security_considerations_pnfs" for
	target="security_considerations_pnfs"/>).		mat="default"/>).
	The degree of impact varies with the		The degree of impact varies with the
	storage protocol (see <xref		storage protocol (see <xref target="storage_protocol" format="default"/
	target="storage_protocol"/>) used for		>) used for
	data access, and can be as low as zero (see		data access, and can be as low as zero (see
	<xref target="file_security_considerations"/>).		<xref target="file_security_considerations" format="default"/>).
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section anchor="file_system_model" title="File System Model">		<section anchor="file_system_model" numbered="true" toc="default">
	<t>		<name>File System Model</name>
			<t>
	The general file system		The general file system
	model used for the NFSv4.1 protocol		model used for the NFSv4.1 protocol
	is the same as previous versions. The server file system is		is the same as previous versions. The server file system is
	hierarchical with the regular files contained within being		hierarchical with the regular files contained within being
	treated as opaque byte		treated as opaque byte
	streams. In a slight departure, file and directory names are encoded		streams. In a slight departure, file and directory names are encoded
	with UTF-8 to deal with the basics of internationalization.		with UTF-8 to deal with the basics of internationalization.
	</t>		</t>
	<t>		<t>
	The NFSv4.1 protocol does not require a separate		The NFSv4.1 protocol does not require a separate
	protocol to provide for the initial mapping between path		protocol to provide for the initial mapping between path
	name and filehandle. All file systems exported by a server		name and filehandle. All file systems exported by a server
	are presented as a tree so that all file systems are reachable		are presented as a tree so that all file systems are reachable
	from a special per-server global root filehandle. This		from a special per-server global root filehandle. This
	allows LOOKUP operations to be used to perform functions		allows LOOKUP operations to be used to perform functions
	previously provided by the MOUNT protocol. The server		previously provided by the MOUNT protocol. The server
	provides any necessary pseudo file systems to bridge any		provides any necessary pseudo file systems to bridge any
	gaps that arise due to unexported gaps between exported		gaps that arise due to unexported gaps between exported
	file systems.		file systems.
	</t>		</t>
	<section anchor="intro_filehandles" title="Filehandles">		<section anchor="intro_filehandles" numbered="true" toc="default">
	<t>		<name>Filehandles</name>
			<t>
	As in previous versions of the NFS protocol, opaque		As in previous versions of the NFS protocol, opaque
	filehandles are used to identify individual files		filehandles are used to identify individual files
	and directories. Lookup-type and create operations		and directories. Lookup-type and create operations
	translate file and directory names to		translate file and directory names to
	filehandles, which are then used to identify objects		filehandles, which are then used to identify objects
	in subsequent operations.		in subsequent operations.
	</t>		</t>
	<t>		<t>
	The NFSv4.1 protocol provides support for		The NFSv4.1 protocol provides support for
	persistent filehandles, guaranteed to be valid		persistent filehandles, guaranteed to be valid
	for the lifetime of the file system object designated.		for the lifetime of the file system object designated.
	In addition, it provides support to servers to provide		In addition, it provides support to servers to provide
	filehandles with more limited validity guarantees,		filehandles with more limited validity guarantees,
	called volatile filehandles.		called volatile filehandles.
	</t>		</t>
	</section>		</section>
	<section anchor="intro_attributes" title="File Attributes">		<section anchor="intro_attributes" numbered="true" toc="default">
	<t>		<name>File Attributes</name>
			<t>
	The NFSv4.1 protocol has a rich and extensible		The NFSv4.1 protocol has a rich and extensible
	file object attribute structure, which is divided		file object attribute structure, which is divided
	into REQUIRED, RECOMMENDED, and named attributes		into <bcp14>REQUIRED</bcp14>, <bcp14>RECOMMENDED</bcp14>, and named att
	(see <xref target="file_attributes"/>).		ributes
			(see <xref target="file_attributes" format="default"/>).
	</t>		</t>
	<t>		<t>
	Several (but not all) of the REQUIRED attributes		Several (but not all) of the <bcp14>REQUIRED</bcp14> attributes
	are derived from the attributes of NFSv3 (see		are derived from the attributes of NFSv3 (see
	the definition of the fattr3 data type in <xref		the definition of the fattr3 data type in <xref target="RFC1813" format
	target="RFC1813"/>). An example of a REQUIRED		="default"/>). An example of a <bcp14>REQUIRED</bcp14>
	attribute is the file object's type (<xref		attribute is the file object's type (<xref target="attrdef_type" format
	target="attrdef_type"/>) so that regular files		="default"/>) so that regular files
	can be distinguished from directories (also known		can be distinguished from directories (also known
	as folders in some operating environments) and		as folders in some operating environments) and
	other types of objects. REQUIRED attributes are		other types of objects. <bcp14>REQUIRED</bcp14> attributes are
	discussed in <xref		discussed in <xref target="mandatory_attributes_intro" format="default"
	target="mandatory_attributes_intro"/>.		/>.
	</t>
	<t>		</t>
	An example of three RECOMMENDED attributes are		<t>
			An example of three <bcp14>RECOMMENDED</bcp14> attributes are
	acl, sacl, and dacl. These attributes define an		acl, sacl, and dacl. These attributes define an
	Access Control List (ACL) on a file object		Access Control List (ACL) on a file object
	(<xref target="acl"/>). An ACL provides		(<xref target="acl" format="default"/>). An ACL provides
	directory and file access control beyond the		directory and file access control beyond the
	model used in NFSv3. The ACL definition allows		model used in NFSv3. The ACL definition allows
	for specification of specific sets of permissions		for specification of specific sets of permissions
	for individual users and groups. In addition,		for individual users and groups. In addition,
	ACL inheritance allows propagation of access		ACL inheritance allows propagation of access
	permissions and restrictions down a directory tree		permissions and restrictions down a directory tree
	as file system objects are created. RECOMMENDED		as file system objects are created. <bcp14>RECOMMENDED</bcp14>
	attributes are discussed in <xref		attributes are discussed in <xref target="recommended_attributes_intro"
	target="recommended_attributes_intro"/>.		format="default"/>.
	</t>		</t>
	<t>		<t>
	A named attribute is an opaque byte stream that is associated		A named attribute is an opaque byte stream that is associated
	with a directory or file and referred to by a string name.		with a directory or file and referred to by a string name.
	Named attributes are meant to be used by client applications		Named attributes are meant to be used by client applications
	as a method to associate application-specific data with a		as a method to associate application-specific data with a
	regular file or directory. NFSv4.1 modifies named attributes		regular file or directory. NFSv4.1 modifies named attributes
	relative to NFSv4.0 by tightening the allowed operations in		relative to NFSv4.0 by tightening the allowed operations in
	order to prevent the development of non-interoperable		order to prevent the development of non-interoperable
	implementations. Named attributes are discussed in <xref target="name d_attributes_intro" />.		implementations. Named attributes are discussed in <xref target="name d_attributes_intro" format="default"/>.
	</t>		</t>
	</section>		</section>
	<section title="Multi-Server Namespace"		<section anchor="PREP-intro" numbered="true" toc="default">
	anchor="PREP-intro">		<name>Multi-Server Namespace</name>
	<t>		<t>
	NFSv4.1 contains a number of features to allow		NFSv4.1 contains a number of features to allow
	implementation of namespaces that cross server boundaries		implementation of namespaces that cross server boundaries
	and that allow and facilitate a non-disruptive transfer of		and that allow and facilitate a nondisruptive transfer of
	support for individual file systems between servers. They		support for individual file systems between servers. They
	are all based upon attributes that allow one file system to		are all based upon attributes that allow one file system to
	specify alternate, additional, and new location information		specify alternate, additional, and new location information
	that specifies how the client may access		that specifies how the client may access
	that file system.		that file system.
	</t>		</t>
	<t>		<t>
	These attributes can be used to provide for individual active		These attributes can be used to provide for individual active
	file systems:		file systems:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Alternate network addresses to access the		Alternate network addresses to access the
	current file system instance.		current file system instance.
	</t>		</li>
	<t>		<li>
	The locations of alternate file system instances		The locations of alternate file system instances
	or replicas to be used in the event that the current		or replicas to be used in the event that the current
	file system instance becomes unavailable.		file system instance becomes unavailable.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	These file system location		These file system location
	attributes may be used together with the concept		attributes may be used together with the concept
	of absent file systems, in which a position in the server		of absent file systems, in which a position in the server
	namespace is associated with locations on other servers without		namespace is associated with locations on other servers without
	there being any corresponding file system instance on the		there being any corresponding file system instance on the
	current server. For example,		current server. For example,
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	These attributes may be used with absent file systems		These attributes may be used with absent file systems
	to implement referrals whereby one server may direct the		to implement referrals whereby one server may direct the
	client to a file system provided by another server. This		client to a file system provided by another server. This
	allows extensive multi-server namespaces to be constructed.		allows extensive multi-server namespaces to be constructed.
	</t>		</li>
	<t>		<li>
	These attributes may be provided when a previously		These attributes may be provided when a previously
	present file system becomes absent. This allows		present file system becomes absent. This allows
	non-disruptive migration of file systems to alternate		nondisruptive migration of file systems to alternate
	servers.		servers.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="intro_locking" numbered="true" toc="default">
	<section anchor="intro_locking" title="Locking Facilities">		<name>Locking Facilities</name>
	<t>		<t>
	As mentioned previously, NFSv4.1 is a single protocol that		As mentioned previously, NFSv4.1 is a single protocol that
	includes locking facilities. These locking facilities		includes locking facilities. These locking facilities
	include support for many types of locks including a number		include support for many types of locks including a number
	of sorts of recallable locks. Recallable locks such as		of sorts of recallable locks. Recallable locks such as
	delegations allow the client to be assured that certain		delegations allow the client to be assured that certain
	events will not occur so long as that lock is held. When		events will not occur so long as that lock is held. When
	circumstances change, the lock is recalled		circumstances change, the lock is recalled
	via a callback request. The assurances provided by		via a callback request. The assurances provided by
	delegations allow more extensive caching to be done safely		delegations allow more extensive caching to be done safely
	when circumstances allow it.		when circumstances allow it.
	</t>
	<t>
	The types of locks are:
	</t>
	<t>
	<list style="symbols">
	<t>
	Share reservations as established by OPEN operations.
	</t>		</t>
	<t>		<t>
	Byte-range locks.		The types of locks are:
	</t>		</t>
	<t>		<ul spacing="normal">
			<li>
			Share reservations as established by OPEN operations.
			</li>
			<li>
			Byte-range locks.
			</li>
			<li>
	File delegations, which are recallable locks that assure		File delegations, which are recallable locks that assure
	the holder that inconsistent opens and file changes cannot		the holder that inconsistent opens and file changes cannot
	occur so long as the delegation is held.		occur so long as the delegation is held.
	</t>		</li>
	<t>		<li>
	Directory delegations, which are recallable locks		Directory delegations, which are recallable locks
	that assure the holder that inconsistent directory		that assure the holder that inconsistent directory
	modifications cannot occur so long as the delegation		modifications cannot occur so long as the delegation
	is held.		is held.
	</t>		</li>
	<t>		<li>
	Layouts, which are recallable objects that assure the		Layouts, which are recallable objects that assure the
	holder that direct access to the file data may be		holder that direct access to the file data may be
	performed directly by the client and that no change		performed directly by the client and that no change
	to the data's location that is inconsistent with that access		to the data's location that is inconsistent with that access
	may be made so long as the layout is held.		may be made so long as the layout is held.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	All locks for a given client are tied together under a		All locks for a given client are tied together under a
	single client-wide lease. All requests made on sessions		single client-wide lease. All requests made on sessions
	associated with the client renew that lease. When the client's		associated with the client renew that lease. When the client's
	lease		lease
	is not promptly renewed, the client's locks are subject to revocation.		is not promptly renewed, the client's locks are subject to revocation.
	In the event of server restart, clients have the		In the event of server restart, clients have the
	opportunity to safely reclaim their locks within a special		opportunity to safely reclaim their locks within a special
	grace period.		grace period.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section anchor="intro_differences" title="Differences from NFSv4.0">		<section anchor="intro_differences" numbered="true" toc="default">
	<t>		<name>Differences from NFSv4.0</name>
			<t>
	The following summarizes the major differences between minor version		The following summarizes the major differences between minor version
	1 and the base protocol:		1 and the base protocol:
	<list style="symbols">
	<t>
	Implementation of the sessions model (<xref target="Session"/>).
	</t>		</t>
	<t>		<ul spacing="normal">
	Parallel access to data (<xref target="pnfs"/>).		<li>
	</t>		Implementation of the sessions model (<xref target="Session" format="d
	<t>		efault"/>).
			</li>
			<li>
			Parallel access to data (<xref target="pnfs" format="default"/>).
			</li>
			<li>
	Addition of the RECLAIM_COMPLETE operation to better structure		Addition of the RECLAIM_COMPLETE operation to better structure
	the lock reclamation process (<xref target="OP_RECLAIM_COMPLETE"/>).		the lock reclamation process (<xref target="OP_RECLAIM_COMPLETE" forma
	</t>		t="default"/>).
			</li>
	<t>		<li>
			<t>
	Enhanced delegation support as follows.		Enhanced delegation support as follows.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Delegations on directories and other		Delegations on directories and other
	file types in addition to regular files (<xref		file types in addition to regular files (<xref target="OP_GET_DIR_DELE
	target="OP_GET_DIR_DELEGATION"/>, <xref		GATION" format="default"/>, <xref target="OP_WANT_DELEGATION" format="default"/>
	target="OP_WANT_DELEGATION"/>).		).
	</t>		</li>
	<t>		<li>
	Operations to optimize acquisition of recalled		Operations to optimize acquisition of recalled
	or denied delegations (<xref		or denied delegations (<xref target="OP_WANT_DELEGATION" format="defau
	target="OP_WANT_DELEGATION"/>, <xref		lt"/>, <xref target="OP_CB_PUSH_DELEG" format="default"/>, <xref target="OP_CB_R
	target="OP_CB_PUSH_DELEG"/>, <xref		ECALLABLE_OBJ_AVAIL" format="default"/>).
	target="OP_CB_RECALLABLE_OBJ_AVAIL"/>).
	</t>
	<t>		</li>
			<li>
	Notifications of changes to files and directories		Notifications of changes to files and directories
	(<xref target="OP_GET_DIR_DELEGATION"/>, <xref		(<xref target="OP_GET_DIR_DELEGATION" format="default"/>, <xref target
	target="OP_CB_NOTIFY"/>).		="OP_CB_NOTIFY" format="default"/>).
	</t>
	<t>		</li>
			<li>
	A method to allow a server to indicate that it is		A method to allow a server to indicate that it is
	recalling one or more delegations for resource		recalling one or more delegations for resource
	management reasons, and thus a method to allow		management reasons, and thus a method to allow
	the client to pick which delegations to return		the client to pick which delegations to return
	(<xref target="OP_CB_RECALL_ANY"/>).		(<xref target="OP_CB_RECALL_ANY" format="default"/>).
	</t>
	</list>
	</t>
	<t>		</li>
			</ul>
			</li>
			<li>
	Attributes can be set atomically		Attributes can be set atomically
	during exclusive file create via the OPEN operation		during exclusive file create via the OPEN operation
	(see the new EXCLUSIVE4_1 creation method in		(see the new EXCLUSIVE4_1 creation method in
	<xref target="OP_OPEN"/>).		<xref target="OP_OPEN" format="default"/>).
	</t>		</li>
	<t>		<li>
	Open files can be preserved if removed and the		Open files can be preserved if removed and the
	hard link count ("hard link" is defined in		hard link count ("hard link" is defined in
	an <xref target="hardlink">Open Group</xref> standard) goes		an <xref target="hardlink" format="default">Open Group</xref> standard) goes
	to zero, thus obviating the		to zero, thus obviating the
	need for clients to rename deleted files to		need for clients to rename deleted files to
	partially hidden names -- colloquially called		partially hidden names -- colloquially called
	"silly rename" (see the new		"silly rename" (see the new
	OPEN4_RESULT_PRESERVE_UNLINKED reply flag in		OPEN4_RESULT_PRESERVE_UNLINKED reply flag in
	<xref target="OP_OPEN"/>).		<xref target="OP_OPEN" format="default"/>).
	</t>		</li>
	<t>		<li>
	Improved compatibility with Microsoft Windows for		Improved compatibility with Microsoft Windows for
	Access Control Lists (<xref		Access Control Lists (<xref target="attrdef_sacl" format="default"/>, <
	target="attrdef_sacl"/>, <xref		xref target="attrdef_dacl" format="default"/>, <xref target="auto_inherit" forma
	target="attrdef_dacl"/>, <xref		t="default"/>).
	target="auto_inherit"/>).
	</t>		</li>
	<t>		<li>
	Data retention (<xref target="retention"/>).		Data retention (<xref target="retention" format="default"/>).
	</t>		</li>
	<t>		<li>
	Identification of the implementation of the NFS client		Identification of the implementation of the NFS client
	and server (<xref target="OP_EXCHANGE_ID"/>).		and server (<xref target="OP_EXCHANGE_ID" format="default"/>).
	</t>
	<t>		</li>
			<li>
	Support for notification of the availability of		Support for notification of the availability of
	byte-range locks (see the new		byte-range locks (see the new
	OPEN4_RESULT_MAY_NOTIFY_LOCK reply flag in <xref		OPEN4_RESULT_MAY_NOTIFY_LOCK reply flag in <xref target="OP_OPEN" forma
	target="OP_OPEN"/> and see <xref		t="default"/> and see <xref target="OP_CB_NOTIFY_LOCK" format="default"/>).
	target="OP_CB_NOTIFY_LOCK"/>).
	</t>
	<t>		</li>
			<li>
	In NFSv4.1, LIPKEY and SPKM-3 are not required security mechanisms		In NFSv4.1, LIPKEY and SPKM-3 are not required security mechanisms
	<xref target="RFC2847"/>.		<xref target="RFC2847" format="default"/>.
	</t>		</li>
			</ul>
	</list>		</section>
	</t>		</section>
	</section>		<section anchor="Core_Infrastructure" numbered="true" toc="default">
	</section>		<name>Core Infrastructure</name>
			<section anchor="Introduction" numbered="true" toc="default">
	<section anchor="Core_Infrastructure" title="Core Infrastructure">		<name>Introduction</name>
			<t>
	<section anchor="Introduction" title="Introduction">
	<t>
	NFSv4.1 relies on core infrastructure common to nearly		NFSv4.1 relies on core infrastructure common to nearly
	every operation. This core infrastructure is described in the remainder		every operation. This core infrastructure is described in the remainder
	of this section.		of this section.
	</t>		</t>
	</section> <!-- Introduction -->		</section>
	<section anchor="RPC_and_XDR" title="RPC and XDR">		<section anchor="RPC_and_XDR" numbered="true" toc="default">
	<t>		<name>RPC and XDR</name>
			<t>
	The NFSv4.1 protocol is a Remote Procedure Call (RPC)		The NFSv4.1 protocol is a Remote Procedure Call (RPC)
	application that uses RPC version 2 and the corresponding eXternal		application that uses RPC version 2 and the corresponding eXternal
	Data Representation (XDR) as defined in		Data Representation (XDR) as defined in
	<xref target="RFC5531"/> and		<xref target="RFC5531" format="default"/> and
	<xref target="RFC4506"/>.		<xref target="RFC4506" format="default"/>.
	</t>		</t>
			<section anchor="RPC-based_Security" numbered="true" toc="default">
	<section anchor="RPC-based_Security" title="RPC-Based Security">		<name>RPC-Based Security</name>
	<t>		<t>
	Previous NFS versions have been thought of as having a		Previous NFS versions have been thought of as having a
	host-based authentication model, where the NFS server		host-based authentication model, where the NFS server
	authenticates the NFS client, and trusts the client		authenticates the NFS client, and trusts the client
	to authenticate all users.		to authenticate all users.
	Actually, NFS has always depended on RPC for		Actually, NFS has always depended on RPC for
	authentication. One of the first forms of RPC authentication,		authentication. One of the first forms of RPC authentication,
	AUTH_SYS, had no strong authentication and		AUTH_SYS, had no strong authentication and
	required a host-based authentication		required a host-based authentication
	approach. NFSv4.1 also depends on RPC for basic security		approach. NFSv4.1 also depends on RPC for basic security
	services and mandates RPC support for a user-based		services and mandates RPC support for a user-based
	authentication model. The user-based authentication		authentication model. The user-based authentication
	model has user principals authenticated by a server, and		model has user principals authenticated by a server, and
	in turn the server authenticated by user principals.		in turn the server authenticated by user principals.
	RPC provides some basic security services that are used		RPC provides some basic security services that are used
	by NFSv4.1.		by NFSv4.1.
	</t>		</t>
			<section anchor="RPC_Security_Flavors" numbered="true" toc="default">
	<section anchor="RPC_Security_Flavors" title="RPC Security Flavors">		<name>RPC Security Flavors</name>
	<t>		<t>
	As described in Section 7.2 ("Authentication") of <xref target="RFC5531"/>,		As described in "Authentication", <xref target="RFC5531" sectionFormat="of"
			section="7"/>,
	RPC security is encapsulated in the RPC header, via a		RPC security is encapsulated in the RPC header, via a
	security or authentication flavor, and information		security or authentication flavor, and information
	specific to the specified security flavor.		specific to the specified security flavor.
	Every RPC header conveys information used to identify		Every RPC header conveys information used to identify
	and authenticate a client and server. As discussed in		and authenticate a client and server. As discussed in
	<xref target="RPCSEC_GSS_and_Security_Services" />,		<xref target="RPCSEC_GSS_and_Security_Services" format="default"/>,
	some security flavors provide additional security		some security flavors provide additional security
	services.		services.
	</t>		</t>
	<t>		<t>
	NFSv4.1 clients and servers MUST implement RPCSEC_GSS.		NFSv4.1 clients and servers <bcp14>MUST</bcp14> implement RPCSEC_GSS.
	(This requirement to implement is not a requirement to		(This requirement to implement is not a requirement to
	use.) Other flavors, such as AUTH_NONE and		use.) Other flavors, such as AUTH_NONE and
	AUTH_SYS, MAY be implemented as well.		AUTH_SYS, <bcp14>MAY</bcp14> be implemented as well.
	</t>		</t>
			<section anchor="RPCSEC_GSS_and_Security_Services" numbered="true" t
	<section anchor="RPCSEC_GSS_and_Security_Services" title="RPCSEC_GSS and Sec		oc="default">
	urity Services">		<name>RPCSEC_GSS and Security Services</name>
	<t>		<t>
	RPCSEC_GSS <xref target="RFC2203" /> uses the		RPCSEC_GSS <xref target="RFC2203" format="default"/> uses the
	functionality of GSS-API <xref target="RFC2743"/>. This allows for the		functionality of GSS-API <xref target="RFC2743" format="default"/>. This
			allows for the
	use of various security mechanisms by the RPC layer		use of various security mechanisms by the RPC layer
	without the additional implementation overhead of		without the additional implementation overhead of
	adding RPC security flavors.		adding RPC security flavors.
	</t>		</t>
			<section anchor="Authentication_Integrity_Privacy" numbered="true"
	<section anchor="Authentication_Integrity_Privacy" title="Identification, A		toc="default">
	uthentication, Integrity, Privacy">		<name>Identification, Authentication, Integrity, Privacy</name>
	<t>		<t>
	Via the GSS-API, RPCSEC_GSS can be used to identify and authenticate		Via the GSS-API, RPCSEC_GSS can be used to identify and authenticate
	users on clients to servers, and servers to users. It can also		users on clients to servers, and servers to users. It can also
	perform integrity checking on the entire RPC message, including		perform integrity checking on the entire RPC message, including
	the RPC header, and on the arguments or results. Finally, privacy,		the RPC header, and on the arguments or results. Finally, privacy,
	usually via encryption, is a service available with RPCSEC_GSS.		usually via encryption, is a service available with RPCSEC_GSS.
	Privacy is performed on the arguments and results. Note that		Privacy is performed on the arguments and results. Note that
	if privacy is selected, integrity, authentication, and identification		if privacy is selected, integrity, authentication, and identification
	are enabled.		are enabled.
	If privacy is not selected, but integrity is selected, authentication		If privacy is not selected, but integrity is selected, authentication
	and identification are enabled. If integrity and privacy are not		and identification are enabled. If integrity and privacy are not
	selected, but authentication is enabled,		selected, but authentication is enabled,
	identification is enabled. RPCSEC_GSS does not provide identification as		identification is enabled. RPCSEC_GSS does not provide identification as
	a separate service.		a separate service.
	</t>		</t>
	<t>		<t>
	Although GSS-API has an authentication service distinct from its		Although GSS-API has an authentication service distinct from its
	privacy and integrity services, GSS-API's		privacy and integrity services, GSS-API's
	authentication service is not used for RPCSEC_GSS's authentication		authentication service is not used for RPCSEC_GSS's authentication
	service. Instead, each RPC request and response header is		service. Instead, each RPC request and response header is
	integrity protected with the GSS-API integrity service, and		integrity protected with the GSS-API integrity service, and
	this allows RPCSEC_GSS to offer per-RPC authentication and		this allows RPCSEC_GSS to offer per-RPC authentication and
	identity. See <xref target="RFC2203" /> for more information.		identity. See <xref target="RFC2203" format="default"/> for more informati
	</t>		on.
	<t>		</t>
	NFSv4.1 client and servers MUST support RPCSEC_GSS's integrity and authent		<t>
	ication		NFSv4.1 client and servers <bcp14>MUST</bcp14> support RPCSEC_GSS's integr
	service. NFSv4.1 servers MUST support RPCSEC_GSS's privacy service.		ity and authentication
	NFSv4.1 clients SHOULD support RPCSEC_GSS's privacy service.		service. NFSv4.1 servers <bcp14>MUST</bcp14> support RPCSEC_GSS's privacy
			service.
			NFSv4.1 clients <bcp14>SHOULD</bcp14> support RPCSEC_GSS's privacy servic
			e.
	</t>		</t>
	</section> <!-- Identity, Authentication, Integrity, Privacy -->		</section>
	<section anchor="security_mechs" title="Security Mechanisms for NFSv4.1">		<section anchor="security_mechs" numbered="true" toc="default">
	<t>		<name>Security Mechanisms for NFSv4.1</name>
			<t>
	RPCSEC_GSS, via GSS-API, normalizes access to mechanisms that		RPCSEC_GSS, via GSS-API, normalizes access to mechanisms that
	provide security services. Therefore, NFSv4.1 clients and servers		provide security services. Therefore, NFSv4.1 clients and servers
	MUST support the Kerberos V5 security mechanism.		<bcp14>MUST</bcp14> support the Kerberos V5 security mechanism.
	</t>		</t>
	<t>		<t>
	The use of RPCSEC_GSS requires selection of mechanism,		The use of RPCSEC_GSS requires selection of mechanism,
	quality of protection (QOP), and service (authentication,		quality of protection (QOP), and service (authentication,
	integrity, privacy). For the mandated security mechanisms,		integrity, privacy). For the mandated security mechanisms,
	NFSv4.1 specifies that a QOP of zero is used, leaving it up		NFSv4.1 specifies that a QOP of zero is used, leaving it up
	to the mechanism or the mechanism's configuration to map		to the mechanism or the mechanism's configuration to map
	QOP zero to		QOP zero to
	an appropriate level of protection.		an appropriate level of protection.
	Each mandated mechanism specifies a minimum set of cryptographic		Each mandated mechanism specifies a minimum set of cryptographic
	algorithms for implementing integrity and privacy. NFSv4.1		algorithms for implementing integrity and privacy. NFSv4.1
	clients and servers MUST be implemented on operating environments		clients and servers <bcp14>MUST</bcp14> be implemented on operating enviro
	that comply with the REQUIRED cryptographic algorithms		nments
	of each REQUIRED mechanism.		that comply with the <bcp14>REQUIRED</bcp14> cryptographic algorithms
	</t>		of each <bcp14>REQUIRED</bcp14> mechanism.
			</t>
	<section anchor="kerberosv5" title="Kerberos V5">		<section anchor="kerberosv5" numbered="true" toc="default">
	<t>		<name>Kerberos V5</name>
			<t>
	The Kerberos V5 GSS-API mechanism as described in		The Kerberos V5 GSS-API mechanism as described in
	<xref target="RFC4121"/> MUST be implemented with		<xref target="RFC4121" format="default"/> <bcp14>MUST</bcp14> be implemen ted with
	the RPCSEC_GSS services as specified in the following		the RPCSEC_GSS services as specified in the following
	table:		table:
	</t>		</t>
	<t>		<artwork name="" type="" align="left" alt=""><![CDATA[
	<figure>
	<artwork>
	column descriptions:		column descriptions:
	1 == number of pseudo flavor		1 == number of pseudo flavor
	2 == name of pseudo flavor		2 == name of pseudo flavor
	3 == mechanism's OID		3 == mechanism's OID
	4 == RPCSEC_GSS service		4 == RPCSEC_GSS service
	5 == NFSv4.1 clients MUST support		5 == NFSv4.1 clients MUST support
	6 == NFSv4.1 servers MUST support		6 == NFSv4.1 servers MUST support
	1 2 3 4 5 6		1 2 3 4 5 6
	------------------------------------------------------------------		------------------------------------------------------------------
	390003 krb5 1.2.840.113554.1.2.2 rpc_gss_svc_none yes yes		390003 krb5 1.2.840.113554.1.2.2 rpc_gss_svc_none yes yes
	390004 krb5i 1.2.840.113554.1.2.2 rpc_gss_svc_integrity yes yes		390004 krb5i 1.2.840.113554.1.2.2 rpc_gss_svc_integrity yes yes
	390005 krb5p 1.2.840.113554.1.2.2 rpc_gss_svc_privacy no yes		390005 krb5p 1.2.840.113554.1.2.2 rpc_gss_svc_privacy no yes
	</artwork>		]]></artwork>
	</figure>		<t>
	</t>
	<t>
	Note that the number and name of the pseudo flavor		Note that the number and name of the pseudo flavor
	are presented here as a mapping aid to the implementor.		are presented here as a mapping aid to the implementor.
	Because the NFSv4.1 protocol includes a method to negotiate		Because the NFSv4.1 protocol includes a method to negotiate
	security and it understands the GSS-API mechanism, the pseudo flavor		security and it understands the GSS-API mechanism, the pseudo flavor
	is not needed. The pseudo flavor is needed for the NFSv3 since the secur ity negotiation is done via		is not needed. The pseudo flavor is needed for the NFSv3 since the secur ity negotiation is done via
	the MOUNT protocol as described in <xref target="RFC2623"/>.		the MOUNT protocol as described in <xref target="RFC2623" format="default
	</t>		"/>.
	<t>		</t>
			<t>
	At the time NFSv4.1 was specified, the Advanced Encryption		At the time NFSv4.1 was specified, the Advanced Encryption
	Standard (AES) with HMAC-SHA1 was		Standard (AES) with HMAC-SHA1 was
	a REQUIRED algorithm set for Kerberos V5. In contrast, when		a <bcp14>REQUIRED</bcp14> algorithm set for Kerberos V5. In contrast, whe
	NFSv4.0 was specified, weaker algorithm sets were REQUIRED for		n
	Kerberos V5, and were REQUIRED in the NFSv4.0 specification, because		NFSv4.0 was specified, weaker algorithm sets were <bcp14>REQUIRED</bcp14>
			for
			Kerberos V5, and were <bcp14>REQUIRED</bcp14> in the NFSv4.0 specificatio
			n, because
	the Kerberos V5 specification at the time did not specify stronger		the Kerberos V5 specification at the time did not specify stronger
	algorithms.		algorithms.
	The NFSv4.1 specification does not specify REQUIRED algorithms		The NFSv4.1 specification does not specify <bcp14>REQUIRED</bcp14> algori thms
	for Kerberos V5, and instead, the implementor is expected		for Kerberos V5, and instead, the implementor is expected
	to track the evolution of the Kerberos V5 standard if and when		to track the evolution of the Kerberos V5 standard if and when
	stronger algorithms are specified.		stronger algorithms are specified.
	</t>		</t>
	<section anchor="krb5_sec_consider"		<section anchor="krb5_sec_consider" numbered="true" toc="defau
	title="Security Considerations for Cryptographic Algorithms in Kerberos V5">		lt">
	<t>		<name>Security Considerations for Cryptographic Algorithms i
			n Kerberos V5</name>
			<t>
	When deploying NFSv4.1, the strength of the security achieved depends		When deploying NFSv4.1, the strength of the security achieved depends
	on the existing Kerberos V5 infrastructure. The algorithms		on the existing Kerberos V5 infrastructure. The algorithms
	of Kerberos V5 are not directly exposed to or selectable by the		of Kerberos V5 are not directly exposed to or selectable by the
	client or server, so there is some due diligence required by		client or server, so there is some due diligence required by
	the user of NFSv4.1 to ensure that security is acceptable		the user of NFSv4.1 to ensure that security is acceptable
	where needed.		where needed.
	</t>		</t>
	</section>		</section>
			</section>
	</section> <!-- Kerberos V5 -->
	</section> <!-- Security mechanisms for NFSv4.1 -->		</section>
	<section anchor="GSS_Server_Principal" title="GSS Server Principal">		<section anchor="GSS_Server_Principal" numbered="true" toc="default">
	<t>		<name>GSS Server Principal</name>
			<t>
	Regardless of what security mechanism under RPCSEC_GSS		Regardless of what security mechanism under RPCSEC_GSS
	is being used, the NFS server MUST identify itself		is being used, the NFS server <bcp14>MUST</bcp14> identify itself
	in GSS-API via a GSS_C_NT_HOSTBASED_SERVICE name type.		in GSS-API via a GSS_C_NT_HOSTBASED_SERVICE name type.
	GSS_C_NT_HOSTBASED_SERVICE names are of the form:		GSS_C_NT_HOSTBASED_SERVICE names are of the form:
	<figure>		</t>
	<artwork>		<artwork name="" type="" align="left" alt=""><![CDATA[
	service@hostname		service@hostname
	</artwork>		]]></artwork>
	</figure>		<t>
	</t>
	<t>
	For NFS, the "service" element is		For NFS, the "service" element is
	<figure>		</t>
	<artwork>		<artwork name="" type="" align="left" alt=""><![CDATA[
	nfs		nfs
	</artwork>		]]></artwork>
	</figure>		<t>
	</t>
	<t>
	Implementations of security mechanisms will convert		Implementations of security mechanisms will convert
	nfs@hostname to various different forms. For Kerberos		nfs@hostname to various different forms. For Kerberos
	V5, the following form is RECOMMENDED:		V5, the following form is <bcp14>RECOMMENDED</bcp14>:
	<figure>		</t>
	<artwork>		<artwork name="" type="" align="left" alt=""><![CDATA[
	nfs/hostname		nfs/hostname
	</artwork>		]]></artwork>
	</figure>		</section>
	</t>		</section>
	</section> <!-- GSS Server Principal -->		</section>
	</section> <!-- RPCSEC_GSS and Security Services -->		</section>
	</section> <!-- RPC Security Flavors -->		</section>
	</section> <!-- RPC-based Security -->
	</section> <!-- RPC and XDR -->
	<section anchor="COMPOUND_and_CB_COMPOUND" title="COMPOUND and CB_COMPOUND">		<section anchor="COMPOUND_and_CB_COMPOUND" numbered="true" toc="default">
	<t>		<name>COMPOUND and CB_COMPOUND</name>
			<t>
	A significant departure from the versions of the NFS		A significant departure from the versions of the NFS
	protocol before NFSv4 is the introduction of the		protocol before NFSv4 is the introduction of the
	COMPOUND procedure. For the NFSv4 protocol,		COMPOUND procedure. For the NFSv4 protocol,
	in all minor versions, there are exactly two RPC procedures,		in all minor versions, there are exactly two RPC procedures,
	NULL and COMPOUND. The COMPOUND procedure is defined		NULL and COMPOUND. The COMPOUND procedure is defined
	as a series of individual operations and these operations		as a series of individual operations and these operations
	perform the sorts of functions performed by traditional		perform the sorts of functions performed by traditional
	NFS procedures.		NFS procedures.
	</t>		</t>
	<t>		<t>
	The operations combined within a COMPOUND		The operations combined within a COMPOUND
	request are evaluated in order by the server, without		request are evaluated in order by the server, without
	any atomicity guarantees. A limited set of facilities		any atomicity guarantees. A limited set of facilities
	exist to pass results from one operation to another. Once an		exist to pass results from one operation to another. Once an
	operation returns a failing result, the evaluation ends		operation returns a failing result, the evaluation ends
	and the results of all		and the results of all
	evaluated operations are returned to the client.		evaluated operations are returned to the client.
	</t>		</t>
	<t>		<t>
	With the use of the COMPOUND procedure, the client is able to build		With the use of the COMPOUND procedure, the client is able to build
	simple or complex requests. These COMPOUND requests allow for a		simple or complex requests. These COMPOUND requests allow for a
	reduction in the number of RPCs needed for logical file system		reduction in the number of RPCs needed for logical file system
	operations. For example, multi-component look up requests can		operations. For example, multi-component look up requests can
	be constructed by combining multiple LOOKUP operations. Those		be constructed by combining multiple LOOKUP operations. Those
	can be further combined with operations such as GETATTR, READDIR,		can be further combined with operations such as GETATTR, READDIR,
	or OPEN plus READ to do more complicated sets of operation without		or OPEN plus READ to do more complicated sets of operation without
	incurring additional latency.		incurring additional latency.
	</t>		</t>
	<t>		<t>
	NFSv4.1 also contains a considerable set of		NFSv4.1 also contains a considerable set of
	callback operations in which the server makes an RPC		callback operations in which the server makes an RPC
	directed at the client. Callback RPCs have a similar		directed at the client. Callback RPCs have a similar
	structure to that of the normal server requests.		structure to that of the normal server requests.
	In all minor versions of the NFSv4 protocol,		In all minor versions of the NFSv4 protocol,
	there are two callback RPC procedures:		there are two callback RPC procedures:
	CB_NULL and CB_COMPOUND. The CB_COMPOUND procedure is defined		CB_NULL and CB_COMPOUND. The CB_COMPOUND procedure is defined
	in an analogous fashion to that of COMPOUND		in an analogous fashion to that of COMPOUND
	with its own set of callback operations.		with its own set of callback operations.
	</t>		</t>
	<t>		<t>
	The addition of new server and callback operations within the		The addition of new server and callback operations within the
	COMPOUND and CB_COMPOUND request		COMPOUND and CB_COMPOUND request
	framework provides a means of extending the protocol in		framework provides a means of extending the protocol in
	subsequent minor versions.		subsequent minor versions.
	</t>		</t>
	<t>		<t>
	Except for a small number of operations needed for session		Except for a small number of operations needed for session
	creation, server requests and callback requests are performed		creation, server requests and callback requests are performed
	within the context of a session. Sessions provide a client		within the context of a session. Sessions provide a client
	context for every request and support robust replay		context for every request and support robust replay
	protection for non-idempotent requests.		protection for non-idempotent requests.
	</t>		</t>
	</section> <!-- COMPOUND and CB_COMPOUND -->		</section>
	<section anchor="Client_Identifiers"		<section anchor="Client_Identifiers" numbered="true" toc="default">
	title="Client Identifiers and Client Owners">		<name>Client Identifiers and Client Owners</name>
	<t>		<t>
	For each operation that obtains or depends on locking state, the		For each operation that obtains or depends on locking state, the
	specific client needs to be identifiable by the server.		specific client needs to be identifiable by the server.
	</t>		</t>
	<t>		<t>
	Each distinct client instance is represented		Each distinct client instance is represented
	by a client ID. A client ID is a 64-bit identifier		by a client ID. A client ID is a 64-bit identifier
	representing a specific client at a given time.		representing a specific client at a given time.
	The client ID is changed whenever the client re-initializes,		The client ID is changed whenever the client re-initializes,
	and may change when the server re-initializes.		and may change when the server re-initializes.
	Client IDs are used to support lock identification		Client IDs are used to support lock identification
	and crash recovery.		and crash recovery.
	</t>		</t>
	<t>		<t>
	During steady state operation,		During steady state operation,
	the client ID associated with each operation		the client ID associated with each operation
	is derived from the session (see <xref target="Session"		is derived from the session (see <xref target="Session" format="default"/>)
	/>) on which the operation is sent. A session is associated with		on which the operation is sent. A session is associated with
	a client ID when the session is created.		a client ID when the session is created.
	</t>		</t>
	<t>		<t>
	Unlike NFSv4.0, the only NFSv4.1 operations possible before a		Unlike NFSv4.0, the only NFSv4.1 operations possible before a
	client ID is established are those needed to		client ID is established are those needed to
	establish the client ID.		establish the client ID.
	</t>		</t>
	<t>		<t>
	A sequence of an EXCHANGE_ID operation followed by a		A sequence of an EXCHANGE_ID operation followed by a
	CREATE_SESSION operation using that client ID		CREATE_SESSION operation using that client ID
	(eir_clientid as returned from EXCHANGE_ID)		(eir_clientid as returned from EXCHANGE_ID)
	is required to establish and confirm the		is required to establish and confirm the
	client ID on the server. Establishment of identification by a		client ID on the server. Establishment of identification by a
	new incarnation of the client also has the effect of immediately		new incarnation of the client also has the effect of immediately
	releasing any locking state that a previous incarnation of that		releasing any locking state that a previous incarnation of that
	same client might have had on the server. Such released state		same client might have had on the server. Such released state
	would include all byte-range lock, share reservation, layout state, and -- w here the server supports neither the CLAIM_DELEGATE_PREV nor CLAIM_DELEG_CUR_FH claim types -- all delegation state associated with the same client with the sam e		would include all byte-range lock, share reservation, layout state, and -- w here the server supports neither the CLAIM_DELEGATE_PREV nor CLAIM_DELEG_CUR_FH claim types -- all delegation state associated with the same client with the sam e
	identity. For discussion of delegation state recovery, see		identity. For discussion of delegation state recovery, see
	<xref target="delegation_recovery" />. For discussion of layout state		<xref target="delegation_recovery" format="default"/>. For discussion of lay
	recovery, see <xref target="pnfs_client_recovery" />.		out state
	</t>		recovery, see <xref target="pnfs_client_recovery" format="default"/>.
	<t>		</t>
			<t>
	Releasing such state requires that the server be able to determine		Releasing such state requires that the server be able to determine
	that one client instance is the successor of another. Where this		that one client instance is the successor of another. Where this
	cannot be done, for any of a number of reasons, the locking state		cannot be done, for any of a number of reasons, the locking state
	will remain for a time subject to lease expiration		will remain for a time subject to lease expiration
	(see <xref target="lease_renewal" />)		(see <xref target="lease_renewal" format="default"/>)
	and the new client will need to wait for		and the new client will need to wait for
	such state to be removed, if it makes conflicting lock requests.		such state to be removed, if it makes conflicting lock requests.
	</t>		</t>
	<t>		<t>
	Client identification is encapsulated in the following client owner		Client identification is encapsulated in the following client owner
	data type:		data type:
	</t>		</t>
	<t>		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct client_owner4 {		struct client_owner4 {
	verifier4 co_verifier;		verifier4 co_verifier;
	opaque co_ownerid&lt;NFS4_OPAQUE_LIMIT>;		opaque co_ownerid<NFS4_OPAQUE_LIMIT>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	</t>
	<t>
	The first field, co_verifier, is a client incarnation		The first field, co_verifier, is a client incarnation
	verifier, allowing the server to distinguish successive incarnations		verifier, allowing the server to distinguish successive incarnations
	(e.g. reboots) of the same client. The server will start the process of		(e.g., reboots) of the same client. The server will start the process of
	canceling the client's leased state if co_verifier		canceling the client's leased state if co_verifier
	is different than what the server has previously		is different than what the server has previously
	recorded for the identified client (as specified in		recorded for the identified client (as specified in
	the co_ownerid field).		the co_ownerid field).
	</t>		</t>
	<t>		<t>
	The second field, co_ownerid, is a variable length string that uniquely defi nes		The second field, co_ownerid, is a variable length string that uniquely defi nes
	the client so that subsequent instances of the same client bear the		the client so that subsequent instances of the same client bear the
	same co_ownerid with a different verifier.		same co_ownerid with a different verifier.
	</t>		</t>
	<t>		<t>
	There are several considerations for how the client		There are several considerations for how the client
	generates the co_ownerid string:		generates the co_ownerid string:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	The string should be unique so that multiple clients		The string should be unique so that multiple clients
	do not present the same string. The consequences of		do not present the same string. The consequences of
	two clients presenting the same string range from		two clients presenting the same string range from
	one client getting an error to one client having its		one client getting an error to one client having its
	leased state abruptly and unexpectedly cancelled.		leased state abruptly and unexpectedly cancelled.
	</t>		</li>
	<t>		<li>
	The string should be selected so that subsequent incarnations		The string should be selected so that subsequent incarnations
	(e.g., restarts) of the same client cause the client to present		(e.g., restarts) of the same client cause the client to present
	the same string. The implementor		the same string. The implementor
	is cautioned from an approach that requires the string to		is cautioned from an approach that requires the string to
	be recorded in a local file because this precludes the use		be recorded in a local file because this precludes the use
	of the implementation in an environment where there is no local		of the implementation in an environment where there is no local
	disk and all file access is from an NFSv4.1 server.		disk and all file access is from an NFSv4.1 server.
	</t>		</li>
	<t>		<li>
	The string should be the same for each server network address that		The string should be the same for each server network address that
	the client accesses.		the client accesses.
	This way, if a server has multiple interfaces, the client		This way, if a server has multiple interfaces, the client
	can trunk traffic over multiple network paths		can trunk traffic over multiple network paths
	as described in <xref target="Trunking" />.		as described in <xref target="Trunking" format="default"/>.
	(Note: the precise opposite was advised in the NFSv4.0		(Note: the precise opposite was advised in the NFSv4.0
	specification <xref target="RFC3530" />.)		specification <xref target="RFC3530" format="default"/>.)
	</t>		</li>
	<t>		<li>
	The algorithm for generating the string should not		The algorithm for generating the string should not
	assume that the client's network address will not		assume that the client's network address will not
	change, unless the client implementation knows it		change, unless the client implementation knows it
	is using statically assigned network addresses.		is using statically assigned network addresses.
	This includes changes between client incarnations		This includes changes between client incarnations
	and even changes while the client is still running		and even changes while the client is still running
	in its current incarnation. Thus, with dynamic		in its current incarnation. Thus, with dynamic
	address assignment, if the		address assignment, if the
	client includes just the client's network address		client includes just the client's network address
	in the co_ownerid string, there is a real risk		in the co_ownerid string, there is a real risk
	that after the		that after the
	client gives up the network address, another		client gives up the network address, another
	client, using a similar algorithm for generating		client, using a similar algorithm for generating
	the co_ownerid string, would generate a conflicting		the co_ownerid string, would generate a conflicting
	co_ownerid string.		co_ownerid string.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Given the above considerations, an example of a well-generated co_ownerid		Given the above considerations, an example of a well-generated co_ownerid
	string is one that includes:		string is one that includes:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	If applicable, the client's statically assigned network address.		If applicable, the client's statically assigned network address.
	</t>		</li>
	<t>		<li>
			<t>
	Additional information that tends to be unique, such as one or more		Additional information that tends to be unique, such as one or more
	of:		of:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	The client machine's serial number (for privacy reasons, it is best		The client machine's serial number (for privacy reasons, it is best
	to perform some one-way function on the serial number).		to perform some one-way function on the serial number).
	</t>		</li>
	<t>		<li>
	A Media Access Control (MAC) address (again, a one-way function shou ld be performed).		A Media Access Control (MAC) address (again, a one-way function shou ld be performed).
	</t>		</li>
	<t>		<li>
	The timestamp of when the NFSv4.1 software was first installed		The timestamp of when the NFSv4.1 software was first installed
	on the client (though this is subject to the previously mentioned		on the client (though this is subject to the previously mentioned
	caution about using information that is stored in a file, because th e		caution about using information that is stored in a file, because th e
	file might only be accessible over NFSv4.1).		file might only be accessible over NFSv4.1).
	</t>		</li>
	<t>		<li>
	A true random number. However, since this number ought to be the sam e		A true random number. However, since this number ought to be the sam e
	between client incarnations, this shares the same problem as that of		between client incarnations, this shares the same problem as that of
	using the timestamp of the software installation.		using the timestamp of the software installation.
	</t>		</li>
	</list>		</ul>
	</t>		</li>
	<t>		<li>
	For a user-level NFSv4.1 client, it should contain additional		For a user-level NFSv4.1 client, it should contain additional
	information to distinguish the client from other user-level clients		information to distinguish the client from other user-level clients
	running on the same host, such as a process identifier or other unique		running on the same host, such as a process identifier or other unique
	sequence.		sequence.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The client ID is assigned by the server (the eir_clientid result from EXCHAN GE_ID)		The client ID is assigned by the server (the eir_clientid result from EXCHAN GE_ID)
	and should be chosen so that it will not		and should be chosen so that it will not
	conflict with a client ID previously assigned by the		conflict with a client ID previously assigned by the
	server. This applies across server restarts.		server. This applies across server restarts.
	</t>		</t>
	<t>		<t>
	In the event of a server restart, a client may find		In the event of a server restart, a client may find
	out that its current client ID is no longer valid when		out that its current client ID is no longer valid when
	it receives an NFS4ERR_STALE_CLIENTID error. The precise		it receives an NFS4ERR_STALE_CLIENTID error. The precise
	circumstances depend on the characteristics of the		circumstances depend on the characteristics of the
	sessions involved, specifically whether the session is		sessions involved, specifically whether the session is
	persistent (see <xref target="Persistence" />), but in		persistent (see <xref target="Persistence" format="default"/>), but in
	each case the client will receive this error when it attempts		each case the client will receive this error when it attempts
	to establish a new session with the existing client ID and		to establish a new session with the existing client ID and
	receives the error NFS4ERR_STALE_CLIENTID, indicating that a new		receives the error NFS4ERR_STALE_CLIENTID, indicating that a new
	client ID needs to be obtained via EXCHANGE_ID and the new session		client ID needs to be obtained via EXCHANGE_ID and the new session
	established with that client ID.		established with that client ID.
	</t>		</t>
	<t>		<t>
	When a session is not persistent, the client will find out that		When a session is not persistent, the client will find out that
	it needs to create a new session as a result of getting an		it needs to create a new session as a result of getting an
	NFS4ERR_BADSESSION, since the session in question was lost		NFS4ERR_BADSESSION, since the session in question was lost
	as part of a server restart. When the existing client ID is		as part of a server restart. When the existing client ID is
	presented to a server as part of creating a session		presented to a server as part of creating a session
	and that client ID is not recognized, as would happen after a server		and that client ID is not recognized, as would happen after a server
	restart, the server will reject the request with the error		restart, the server will reject the request with the error
	NFS4ERR_STALE_CLIENTID.		NFS4ERR_STALE_CLIENTID.
	</t>		</t>
	<t>		<t>
	In the case of the session being persistent, the		In the case of the session being persistent, the
	client will re-establish communication using the		client will re-establish communication using the
	existing session after the restart. This session		existing session after the restart. This session
	will be associated with the existing client ID but		will be associated with the existing client ID but
	may only be used to retransmit operations that the		may only be used to retransmit operations that the
	client previously transmitted and did not see replies		client previously transmitted and did not see replies
	to. Replies to operations that the server previously performed		to. Replies to operations that the server previously performed
	will come from the reply cache; otherwise,		will come from the reply cache; otherwise,
	NFS4ERR_DEADSESSION will be returned.		NFS4ERR_DEADSESSION will be returned.
	Hence, such a session is referred to as "dead". In this situation,		Hence, such a session is referred to as "dead". In this situation,
	in order to perform new operations, the client needs to		in order to perform new operations, the client needs to
	establish a new session. If an attempt is made to		establish a new session. If an attempt is made to
	establish this new session with the existing client ID,		establish this new session with the existing client ID,
	the server will reject the request with		the server will reject the request with
	NFS4ERR_STALE_CLIENTID.		NFS4ERR_STALE_CLIENTID.
	</t>		</t>
	<t>		<t>
	When NFS4ERR_STALE_CLIENTID is received in either of		When NFS4ERR_STALE_CLIENTID is received in either of
	these situations, the client needs to obtain a		these situations, the client needs to obtain a
	new client ID by use of the EXCHANGE_ID operation, then		new client ID by use of the EXCHANGE_ID operation, then
	use that client ID as the basis of a new session, and		use that client ID as the basis of a new session, and
	then proceed to		then proceed to
	any other necessary recovery for the server restart case (see		any other necessary recovery for the server restart case (see
	<xref target="server_failure" />).		<xref target="server_failure" format="default"/>).
	</t>		</t>
	<t>		<t>
	See the descriptions of EXCHANGE_ID		See the descriptions of EXCHANGE_ID
	(<xref target="OP_EXCHANGE_ID" />) and CREATE_SESSION		(<xref target="OP_EXCHANGE_ID" format="default"/>) and CREATE_SESSION
	(<xref target="OP_CREATE_SESSION" />) for a complete		(<xref target="OP_CREATE_SESSION" format="default"/>) for a complete
	specification of these operations.		specification of these operations.
	</t>		</t>
	<section title="Upgrade from NFSv4.0 to NFSv4.1" >		<section numbered="true" toc="default">
	<t>		<name>Upgrade from NFSv4.0 to NFSv4.1</name>
			<t>
	To facilitate upgrade from NFSv4.0 to NFSv4.1, a server		To facilitate upgrade from NFSv4.0 to NFSv4.1, a server
	may compare a value of data type client_owner4 in an EXCHANGE_ID with a		may compare a value of data type client_owner4 in an EXCHANGE_ID with a
	value of data type nfs_client_id4 that was established using the SETCLIENTID operation of		value of data type nfs_client_id4 that was established using the SETCLIENTID operation of
	NFSv4.0. A server that does so will allow		NFSv4.0. A server that does so will allow
	an upgraded client to avoid waiting		an upgraded client to avoid waiting
	until the lease (i.e., the lease established by the NFSv4.0 instance		until the lease (i.e., the lease established by the NFSv4.0 instance
	client) expires.		client) expires.
	This requires that the value of data type client_owner4 be constructed		This requires that the value of data type client_owner4 be constructed
	the same way as the value of data type nfs_client_id4. If the latter's		the same way as the value of data type nfs_client_id4. If the latter's
	contents included the server's network address (per the		contents included the server's network address (per the
	recommendations of the NFSv4.0 specification <xref target="RFC3530" />), and		recommendations of the NFSv4.0 specification <xref target="RFC3530" format=" default"/>), and
	the NFSv4.1 client does not wish to use a client		the NFSv4.1 client does not wish to use a client
	ID that prevents trunking, it should send two		ID that prevents trunking, it should send two
	EXCHANGE_ID operations. The first EXCHANGE_ID will		EXCHANGE_ID operations. The first EXCHANGE_ID will
	have a client_owner4 equal to the nfs_client_id4.		have a client_owner4 equal to the nfs_client_id4.
	This will clear the state created by the NFSv4.0		This will clear the state created by the NFSv4.0
	client. The second EXCHANGE_ID will not have the		client. The second EXCHANGE_ID will not have the
	server's network address. The state created for the		server's network address. The state created for the
	second EXCHANGE_ID will not have to wait for lease		second EXCHANGE_ID will not have to wait for lease
	expiration, because there will be no state to expire.		expiration, because there will be no state to expire.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="Server Release of Client ID" >		<name>Server Release of Client ID</name>
	<t>		<t>
	NFSv4.1 introduces a new operation called		NFSv4.1 introduces a new operation called
	DESTROY_CLIENTID (<xref target="OP_DESTROY_CLIENTID" />),		DESTROY_CLIENTID (<xref target="OP_DESTROY_CLIENTID" format="default"/>),
	which the client SHOULD use to destroy a client ID it		which the client <bcp14>SHOULD</bcp14> use to destroy a client ID it
	no longer needs. This permits graceful, bilateral release of		no longer needs. This permits graceful, bilateral release of
	a client ID. The operation cannot be used if there are sessions		a client ID. The operation cannot be used if there are sessions
	associated with the client ID, or state with an unexpired lease.		associated with the client ID, or state with an unexpired lease.
	</t>		</t>
	<t>		<t>
	If the server determines that the client holds no associated state		If the server determines that the client holds no associated state
	for its client ID (associated state includes unrevoked sessions,		for its client ID (associated state includes unrevoked sessions,
	opens, locks, delegations, layouts, and wants), the server MAY		opens, locks, delegations, layouts, and wants), the server <bcp14>MAY</bcp1 4>
	choose to unilaterally release the client ID in order to		choose to unilaterally release the client ID in order to
	conserve resources.		conserve resources.
	If the client		If the client
	contacts the server after this release, the server		contacts the server after this release, the server
	MUST ensure that the client receives the appropriate error		<bcp14>MUST</bcp14> ensure that the client receives the appropriate error
	so that it will use the EXCHANGE_ID/CREATE_SESSION		so that it will use the EXCHANGE_ID/CREATE_SESSION
	sequence to establish a new client ID.		sequence to establish a new client ID.
	The server ought to be very hesitant to		The server ought to be very hesitant to
	release a client ID since the resulting work on the		release a client ID since the resulting work on the
	client to recover from such an event will be the same		client to recover from such an event will be the same
	burden as if the server had failed and restarted.		burden as if the server had failed and restarted.
	Typically, a server would not release a client ID		Typically, a server would not release a client ID
	unless there had been no activity from that client		unless there had been no activity from that client
	for many minutes. As long as there are sessions,		for many minutes. As long as there are sessions,
	opens, locks, delegations, layouts, or wants, the		opens, locks, delegations, layouts, or wants, the
	server MUST NOT release the client ID. See <xref		server <bcp14>MUST NOT</bcp14> release the client ID. See <xref target="los
	target="loss_of_session" /> for discussion on		s_of_session" format="default"/> for discussion on
	releasing inactive sessions.		releasing inactive sessions.
	</t>		</t>
	</section> <!-- Server Release of Client ID -->		</section>
	<section title="Resolving Client Owner Conflicts" anchor="cowner_conflicts">		<section anchor="cowner_conflicts" numbered="true" toc="default">
	<t>		<name>Resolving Client Owner Conflicts</name>
			<t>
	When the server gets an EXCHANGE_ID for a client owner that		When the server gets an EXCHANGE_ID for a client owner that
	currently has no state, or that has state but the lease has expired,		currently has no state, or that has state but the lease has expired,
	the server MUST allow the		the server <bcp14>MUST</bcp14> allow the
	EXCHANGE_ID and confirm the new client ID if followed by the		EXCHANGE_ID and confirm the new client ID if followed by the
	appropriate CREATE_SESSION.		appropriate CREATE_SESSION.
	</t>		</t>
	<t>		<t>
	When the server gets an EXCHANGE_ID for a		When the server gets an EXCHANGE_ID for a
	new incarnation of a client owner that		new incarnation of a client owner that
	currently has an old incarnation with state and an unexpired lease, the		currently has an old incarnation with state and an unexpired lease, the
	server is allowed to dispose of the state of the		server is allowed to dispose of the state of the
	previous incarnation of the client owner if		previous incarnation of the client owner if
	one of the following is true:		one of the following is true:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The principal that created the client ID for the client owner		The principal that created the client ID for the client owner
	is the same as the principal that is sending the EXCHANGE_ID operation.		is the same as the principal that is sending the EXCHANGE_ID operation.
	Note that if the client ID was created with		Note that if the client ID was created with
	SP4_MACH_CRED state protection (<xref target="OP_EXCHANGE_ID" />),		SP4_MACH_CRED state protection (<xref target="OP_EXCHANGE_ID" format="def
	the principal MUST be based on RPCSEC_GSS authentication,		ault"/>),
	the RPCSEC_GSS service used MUST be integrity or		the principal <bcp14>MUST</bcp14> be based on RPCSEC_GSS authentication,
			the RPCSEC_GSS service used <bcp14>MUST</bcp14> be integrity or
	privacy, and the		privacy, and the
	same GSS mechanism and principal		same GSS mechanism and principal
	MUST be used as that used when the client ID		<bcp14>MUST</bcp14> be used as that used when the client ID
	was created.		was created.
	</t>		</li>
	<t>		<li>
	The client ID was established with SP4_SSV		The client ID was established with SP4_SSV
	protection (<xref target="OP_EXCHANGE_ID" />,		protection (<xref target="OP_EXCHANGE_ID" format="default"/>,
	<xref target="protect_state_change" />)		<xref target="protect_state_change" format="default"/>)
	and the client sends the EXCHANGE_ID with the		and the client sends the EXCHANGE_ID with the
	security flavor set to RPCSEC_GSS using the GSS		security flavor set to RPCSEC_GSS using the GSS
	SSV mechanism (<xref target="ssv_mech" />).		SSV mechanism (<xref target="ssv_mech" format="default"/>).
	</t>		</li>
	<t>		<li>
	The client ID was established with SP4_SSV		The client ID was established with SP4_SSV
	protection, and under the conditions described herein,		protection, and under the conditions described herein,
	the EXCHANGE_ID was sent with SP4_MACH_CRED state protection.		the EXCHANGE_ID was sent with SP4_MACH_CRED state protection.
	Because the SSV might not persist		Because the SSV might not persist
	across client and server restart, and because		across client and server restart, and because
	the first time a client sends EXCHANGE_ID to		the first time a client sends EXCHANGE_ID to
	a server it does not have an SSV, the client		a server it does not have an SSV, the client
	MAY send the subsequent EXCHANGE_ID without		<bcp14>MAY</bcp14> send the subsequent EXCHANGE_ID without
	an SSV RPCSEC_GSS handle. Instead, as with		an SSV RPCSEC_GSS handle. Instead, as with
	SP4_MACH_CRED protection, the principal MUST be		SP4_MACH_CRED protection, the principal <bcp14>MUST</bcp14> be
	based on RPCSEC_GSS authentication, the RPCSEC_GSS		based on RPCSEC_GSS authentication, the RPCSEC_GSS
	service used MUST be integrity or privacy, and the		service used <bcp14>MUST</bcp14> be integrity or privacy, and the
	same GSS mechanism and principal MUST be used as		same GSS mechanism and principal <bcp14>MUST</bcp14> be used as
	that used when the client ID was created.		that used when the client ID was created.
	</t>		</li>
	</list>		</ul>
			<t>
	If none of the above situations apply, the server		If none of the above situations apply, the server
	MUST return NFS4ERR_CLID_INUSE.		<bcp14>MUST</bcp14> return NFS4ERR_CLID_INUSE.
	</t>		</t>
	<t>		<t>
	If the server accepts the principal and co_ownerid		If the server accepts the principal and co_ownerid
	as matching that which created the client ID, and		as matching that which created the client ID, and
	the co_verifier in the EXCHANGE_ID differs from the		the co_verifier in the EXCHANGE_ID differs from the
	co_verifier used when the client ID was created,		co_verifier used when the client ID was created,
	then after the server receives a CREATE_SESSION that		then after the server receives a CREATE_SESSION that
	confirms the client ID, the server deletes state.		confirms the client ID, the server deletes state.
	If the co_verifier values are the same (e.g., the		If the co_verifier values are the same (e.g., the
	client either is updating properties of the client ID		client either is updating properties of the client ID
	(<xref target="OP_EXCHANGE_ID" />) or		(<xref target="OP_EXCHANGE_ID" format="default"/>) or
	is attempting trunking (<xref target="Trunking" />),		is attempting trunking (<xref target="Trunking" format="default"/>),
	the server MUST NOT delete state.		the server <bcp14>MUST NOT</bcp14> delete state.
	</t>
	</section> <!-- Handling Client Owner Conflicts -->		</t>
	</section> <!-- Client Identifiers -->		</section>
	<section anchor="Server_Owners" title="Server Owners">		</section>
	<t>		<section anchor="Server_Owners" numbered="true" toc="default">
			<name>Server Owners</name>
			<t>
	The server owner is similar to a client owner		The server owner is similar to a client owner
	(<xref target="Client_Identifiers" />), but unlike the		(<xref target="Client_Identifiers" format="default"/>), but unlike the
	client owner, there is no shorthand server ID.		client owner, there is no shorthand server ID.
	The server owner is defined in the following data type:		The server owner is defined in the following data type:
	</t>		</t>
	<t>		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct server_owner4 {		struct server_owner4 {
	uint64_t so_minor_id;		uint64_t so_minor_id;
	opaque so_major_id&lt;NFS4_OPAQUE_LIMIT>;		opaque so_major_id<NFS4_OPAQUE_LIMIT>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	</t>
	<t>
	The server owner is returned from		The server owner is returned from
	EXCHANGE_ID. When the so_major_id fields are the same in		EXCHANGE_ID. When the so_major_id fields are the same in
	two EXCHANGE_ID results, the connections that each EXCHANGE_ID		two EXCHANGE_ID results, the connections that each EXCHANGE_ID
	were sent over can be assumed to address the same server		were sent over can be assumed to address the same server
	(as defined in <xref target="intro_definitions" />). If		(as defined in <xref target="intro_definitions" format="default"/>). If
	the so_minor_id fields are also the same, then not only		the so_minor_id fields are also the same, then not only
	do both connections connect to the same server, but the		do both connections connect to the same server, but the
	session can be shared across both		session can be shared across both
	connections. The reader is cautioned that multiple		connections. The reader is cautioned that multiple
	servers may deliberately or accidentally claim to have		servers may deliberately or accidentally claim to have
	the same so_major_id or so_major_id/so_minor_id; the		the same so_major_id or so_major_id/so_minor_id; the
	reader should examine Sections <xref target="Trunking" format="counter" /> an		reader should examine Sections <xref target="Trunking" format="counter"/> and
	d		<xref target="OP_EXCHANGE_ID" format="counter"/> in order to avoid
	<xref target="OP_EXCHANGE_ID" format="counter" /> in order to avoid
	acting on falsely matching server owner values.		acting on falsely matching server owner values.
	</t>		</t>
	<t>		<t>
	The considerations for generating an so_major_id are		The considerations for generating an so_major_id are
	similar to that for generating a co_ownerid string (see		similar to that for generating a co_ownerid string (see
	<xref target="Client_Identifiers" />). The consequences		<xref target="Client_Identifiers" format="default"/>). The consequences
	of two servers generating conflicting so_major_id values		of two servers generating conflicting so_major_id values
	are less dire than they are for co_ownerid conflicts		are less dire than they are for co_ownerid conflicts
	because the client can use RPCSEC_GSS to compare the		because the client can use RPCSEC_GSS to compare the
	authenticity of each server		authenticity of each server
	(see <xref target="Trunking" />).		(see <xref target="Trunking" format="default"/>).
	</t>		</t>
	</section> <!-- Server Owners -->		</section>
	<section anchor="Security_Service_Negotiation" title="Security Service Negotiat		<section anchor="Security_Service_Negotiation" numbered="true" toc="default">
	ion">		<name>Security Service Negotiation</name>
	<t>		<t>
	With the NFSv4.1 server potentially offering		With the NFSv4.1 server potentially offering
	multiple security mechanisms, the client needs a method		multiple security mechanisms, the client needs a method
	to determine or negotiate which mechanism is to be		to determine or negotiate which mechanism is to be
	used for its communication with the server. The NFS		used for its communication with the server. The NFS
	server may have multiple points within its file system		server may have multiple points within its file system
	namespace that are available for use by NFS clients.		namespace that are available for use by NFS clients.
	These points can be considered security policy boundaries,		These points can be considered security policy boundaries,
	and, in some NFS implementations, are tied to NFS export points.		and, in some NFS implementations, are tied to NFS export points.
	In turn, the NFS server may be configured such that each		In turn, the NFS server may be configured such that each
	of these security policy boundaries may have different or multiple		of these security policy boundaries may have different or multiple
	security mechanisms in use.		security mechanisms in use.
	</t>		</t>
	<t>		<t>
	The security negotiation between client and server		The security negotiation between client and server
	SHOULD be done with a secure channel to eliminate		<bcp14>SHOULD</bcp14> be done with a secure channel to eliminate
	the possibility of a third party intercepting the		the possibility of a third party intercepting the
	negotiation sequence and forcing the client and server		negotiation sequence and forcing the client and server
	to choose a lower level of security than required or		to choose a lower level of security than required or
	desired. See		desired. See
	<xref target="SECCON" /> for further discussion.		<xref target="SECCON" format="default"/> for further discussion.
	</t>		</t>
			<section anchor="NFSv4_Security_Tuples" numbered="true" toc="default">
	<section anchor="NFSv4_Security_Tuples" title="NFSv4.1 Security Tuples">		<name>NFSv4.1 Security Tuples</name>
	<t>		<t>
	An NFS server can assign one or more "security tuples" to each		An NFS server can assign one or more "security tuples" to each
	security policy boundary in its namespace. Each security tuple		security policy boundary in its namespace. Each security tuple
	consists of a security flavor		consists of a security flavor
	(see <xref target="RPC_Security_Flavors" />) and, if the flavor		(see <xref target="RPC_Security_Flavors" format="default"/>) and, if the flav or
	is RPCSEC_GSS, a GSS-API mechanism Object Identifier (OID), a GSS-API quality of		is RPCSEC_GSS, a GSS-API mechanism Object Identifier (OID), a GSS-API quality of
	protection, and an RPCSEC_GSS service.		protection, and an RPCSEC_GSS service.
	</t>		</t>
	</section> <!-- NFSv4.1 Security Tuples -->		</section>
	<section anchor="SECINFO_and_SECINFO_NO_NAME" title="SECINFO and SECINFO_NO_NA		<section anchor="SECINFO_and_SECINFO_NO_NAME" numbered="true" toc="default">
	ME">		<name>SECINFO and SECINFO_NO_NAME</name>
	<t>		<t>
	The SECINFO and SECINFO_NO_NAME operations allow the client to		The SECINFO and SECINFO_NO_NAME operations allow the client to
	determine, on a per-filehandle basis, what security tuple is to be		determine, on a per-filehandle basis, what security tuple is to be
	used for server access. In general, the client will not have to		used for server access. In general, the client will not have to
	use either operation except during initial communication with the		use either operation except during initial communication with the
	server or when the client crosses security policy boundaries at the		server or when the client crosses security policy boundaries at the
	server. However, the server's policies may also change at any time		server. However, the server's policies may also change at any time
	and force the client to negotiate a new security tuple.		and force the client to negotiate a new security tuple.
	</t>		</t>
	<t>		<t>
	Where the use of different security tuples would affect the type of		Where the use of different security tuples would affect the type of
	access that would be allowed if a request was sent over the same		access that would be allowed if a request was sent over the same
	connection used for the SECINFO or SECINFO_NO_NAME operation		connection used for the SECINFO or SECINFO_NO_NAME operation
	(e.g., read-only vs. read-write) access, security tuples that allow		(e.g., read-only vs. read-write) access, security tuples that allow
	greater access should be presented first. Where the general level		greater access should be presented first. Where the general level
	of access is the same and different security flavors limit the		of access is the same and different security flavors limit the
	range of principals whose privileges are recognized (e.g., allowing		range of principals whose privileges are recognized (e.g., allowing
	or disallowing root access), flavors supporting the greatest range		or disallowing root access), flavors supporting the greatest range
	of principals should be listed first.		of principals should be listed first.
	</t>		</t>
	</section> <!-- SECINFO and SECINFO_NO_NAME -->		</section>
	<section anchor="Security_Error" title="Security Error">		<section anchor="Security_Error" numbered="true" toc="default">
	<t>		<name>Security Error</name>
			<t>
	Based on the assumption that each NFSv4.1 client		Based on the assumption that each NFSv4.1 client
	and server MUST support a minimum set of security (i.e.,		and server <bcp14>MUST</bcp14> support a minimum set of security (i.e.,
	Kerberos V5 under RPCSEC_GSS),		Kerberos V5 under RPCSEC_GSS),
	the NFS client will initiate file access to the server		the NFS client will initiate file access to the server
	with one of the minimal security tuples. During		with one of the minimal security tuples. During
	communication with the server, the client may receive an		communication with the server, the client may receive an
	NFS error of NFS4ERR_WRONGSEC. This error allows the		NFS error of NFS4ERR_WRONGSEC. This error allows the
	server to notify the client that the security tuple		server to notify the client that the security tuple
	currently being used contravenes the server's		currently being used contravenes the server's
	security policy. The client is then responsible for		security policy. The client is then responsible for
	determining (see <xref target="using_secinfo" />) what		determining (see <xref target="using_secinfo" format="default"/>) what
	security tuples are available at the server and choosing		security tuples are available at the server and choosing
	one that is appropriate for the client.		one that is appropriate for the client.
	</t>		</t>
			<section anchor="using_secinfo" numbered="true" toc="default">
	<section anchor="using_secinfo" title="Using NFS4ERR_WRONGSEC, SECINFO, and SE		<name>Using NFS4ERR_WRONGSEC, SECINFO, and SECINFO_NO_NAME</name>
	CINFO_NO_NAME">		<t>
	<t>
	This section explains the mechanics of NFSv4.1 security negotiation.		This section explains the mechanics of NFSv4.1 security negotiation.
	</t>		</t>
			<section anchor="putfh_series" numbered="true" toc="default">
	<section anchor="putfh_series" title="Put Filehandle Operations">		<name>Put Filehandle Operations</name>
			<t>
	<t>
	The term "put filehandle operation" refers to		The term "put filehandle operation" refers to
	PUTROOTFH, PUTPUBFH, PUTFH, and RESTOREFH. Each of the subsections		PUTROOTFH, PUTPUBFH, PUTFH, and RESTOREFH. Each of the subsections
	herein describes how the server handles a subseries of operations		herein describes how the server handles a subseries of operations
	that starts with a put filehandle operation.		that starts with a put filehandle operation.
	</t>		</t>
			<section anchor="PUTFHplusSAVEFH" numbered="true" toc="default">
	<section anchor="PUTFHplusSAVEFH"		<name>Put Filehandle Operation + SAVEFH</name>
	title="Put Filehandle Operation + SAVEFH">		<t>
	<t>
	The client is saving a filehandle for a future		The client is saving a filehandle for a future
	RESTOREFH, LINK, or RENAME. SAVEFH MUST NOT		RESTOREFH, LINK, or RENAME. SAVEFH <bcp14>MUST NOT</bcp14>
	return NFS4ERR_WRONGSEC. To determine whether or not the put		return NFS4ERR_WRONGSEC. To determine whether or not the put
	filehandle operation returns NFS4ERR_WRONGSEC,		filehandle operation returns NFS4ERR_WRONGSEC,
	the server implementation pretends SAVEFH is not in		the server implementation pretends SAVEFH is not in
	the series of operations and examines which of the		the series of operations and examines which of the
	situations described in the other subsections of <xref		situations described in the other subsections of <xref target="putfh_series"
	target="putfh_series"/> apply.		format="default"/> apply.
	</t>		</t>
	</section> <!-- Put Filehandle Operation + SAVEFH -->		</section>
	<section anchor="PUTFHplusPUTFH"		<section anchor="PUTFHplusPUTFH" numbered="true" toc="default">
	title="Two or More Put Filehandle Operations">		<name>Two or More Put Filehandle Operations</name>
	<t>		<t>
	For a series of N put filehandle operations, the server		For a series of N put filehandle operations, the server
	MUST NOT return NFS4ERR_WRONGSEC to the first N-1 put		<bcp14>MUST NOT</bcp14> return NFS4ERR_WRONGSEC to the first N-1 put
	filehandle operations.		filehandle operations.
	The Nth put filehandle operation		The Nth put filehandle operation
	is handled as if it is the first in a subseries of		is handled as if it is the first in a subseries of
	operations.		operations.
	For example, if the		For example, if the
	server received a COMPOUND request with this series of		server received a COMPOUND request with this series of
	operations -- PUTFH, PUTROOTFH, LOOKUP -- then the		operations -- PUTFH, PUTROOTFH, LOOKUP -- then the
	PUTFH operation is ignored for NFS4ERR_WRONGSEC purposes, and the		PUTFH operation is ignored for NFS4ERR_WRONGSEC purposes, and the
	PUTROOTFH, LOOKUP subseries is processed as according		PUTROOTFH, LOOKUP subseries is processed as according
	to <xref target="PUTFHplusLOOKUP"/>.		to <xref target="PUTFHplusLOOKUP" format="default"/>.
	</t>		</t>
	</section> <!-- PUTFH + PUTFH -->		</section>
	<section anchor="PUTFHplusLOOKUP"		<section anchor="PUTFHplusLOOKUP" numbered="true" toc="default">
	title="Put Filehandle Operation + LOOKUP (or OPEN of an Existing Name)">		<name>Put Filehandle Operation + LOOKUP (or OPEN of an Existing
	<t>		Name)</name>
			<t>
	This situation also applies to a put filehandle operation followed		This situation also applies to a put filehandle operation followed
	by a LOOKUP or an OPEN operation that specifies an existing component name.		by a LOOKUP or an OPEN operation that specifies an existing component name.
	</t>		</t>
	<t>		<t>
	In this situation, the client is potentially crossing		In this situation, the client is potentially crossing
	a security policy boundary, and the set of security tuples		a security policy boundary, and the set of security tuples
	the parent directory supports may differ from those of		the parent directory supports may differ from those of
	the child.		the child.
	The server implementation may decide whether to impose		The server implementation may decide whether to impose
	any restrictions on security policy administration.		any restrictions on security policy administration.
	There are at least three approaches (sec_policy_child is		There are at least three approaches (sec_policy_child is
	the tuple set of the child export, sec_policy_parent is		the tuple set of the child export, sec_policy_parent is
	that of the parent).		that of the parent).
	</t>		</t>
	<t>		<ol spacing="normal" type="(%c)">
	<list style="format (%c)">		<li>
	<t>
	sec_policy_child &lt;= sec_policy_parent (&lt;= for subset). This		sec_policy_child &lt;= sec_policy_parent (&lt;= for subset). This
	means that the set of security tuples specified on the		means that the set of security tuples specified on the
	security policy of a child directory is always a subset		security policy of a child directory is always a subset
	of its parent directory.		of its parent directory.
	</t>		</li>
	<t>		<li>
	sec_policy_child ^ sec_policy_parent != {} (^ for intersection, {}		sec_policy_child ^ sec_policy_parent != {} (^ for intersection, {}
	for the empty set). This means that the set of security tuples specified		for the empty set). This means that the set of security tuples specified
	on the security policy of a child directory always has a non-empty intersect ion		on the security policy of a child directory always has a non-empty intersect ion
	with that of the parent.		with that of the parent.
	</t>		</li>
	<t>		<li>
	sec_policy_child ^ sec_policy_parent == {}. This means that the		sec_policy_child ^ sec_policy_parent == {}. This means that the
	set of security tuples specified on the security policy of a child directory		set of security tuples specified on the security policy of a child directory
	may not intersect with that of the parent. In other words, there		may not intersect with that of the parent. In other words, there
	are no restrictions on how the system administrator may		are no restrictions on how the system administrator may
	set up these tuples.		set up these tuples.
	</t>		</li>
	</list>		</ol>
	</t>		<t>
	<t>
	In order for a server to support approaches (b)		In order for a server to support approaches (b)
	(for the case when a client chooses a flavor that is		(for the case when a client chooses a flavor that is
	not a member of sec_policy_parent) and (c), the put		not a member of sec_policy_parent) and (c), the put
	filehandle operation cannot return NFS4ERR_WRONGSEC		filehandle operation cannot return NFS4ERR_WRONGSEC
	when there is a security tuple mismatch. Instead,		when there is a security tuple mismatch. Instead,
	it should be returned from the LOOKUP (or OPEN by		it should be returned from the LOOKUP (or OPEN by
	existing component name) that follows.		existing component name) that follows.
	</t>		</t>
	<t>		<t>
	Since the above guideline does not contradict approach		Since the above guideline does not contradict approach
	(a), it should be followed in general. Even if approach		(a), it should be followed in general. Even if approach
	(a) is implemented, it is possible for the security		(a) is implemented, it is possible for the security
	tuple used to be acceptable for the target of LOOKUP		tuple used to be acceptable for the target of LOOKUP
	but not for the filehandles used in the put filehandle operation. The		but not for the filehandles used in the put filehandle operation. The
	put filehandle operation		put filehandle operation
	could be a PUTROOTFH or PUTPUBFH, where the		could be a PUTROOTFH or PUTPUBFH, where the
	client cannot know the security tuples for the root		client cannot know the security tuples for the root
	or public filehandle. Or the security policy for the		or public filehandle. Or the security policy for the
	filehandle used by the put filehandle operation		filehandle used by the put filehandle operation
	could have changed since the		could have changed since the
	time the filehandle was obtained.		time the filehandle was obtained.
	</t>		</t>
	<t>		<t>
	Therefore, an NFSv4.1 server MUST NOT return NFS4ERR_WRONGSEC		Therefore, an NFSv4.1 server <bcp14>MUST NOT</bcp14> return NFS4ERR_WRONGSEC
	in response to the put filehandle operation		in response to the put filehandle operation
	if the operation		if the operation
	is immediately followed by a LOOKUP or an OPEN by component name.		is immediately followed by a LOOKUP or an OPEN by component name.
	</t>		</t>
	</section> <!-- PUTFH + LOOKUP -->		</section>
	<section anchor="PUTFHplusLOOKUPP" title="Put Filehandle Operation + LOOKUPP"		<section anchor="PUTFHplusLOOKUPP" numbered="true" toc="default">
	>		<name>Put Filehandle Operation + LOOKUPP</name>
	<t>		<t>
	Since SECINFO only works its way down, there is no way LOOKUPP can		Since SECINFO only works its way down, there is no way LOOKUPP can
	return NFS4ERR_WRONGSEC without SECINFO_NO_NAME. SECINFO_NO_NAME		return NFS4ERR_WRONGSEC without SECINFO_NO_NAME. SECINFO_NO_NAME
	solves this issue via style		solves this issue via style
	SECINFO_STYLE4_PARENT, which works in the opposite direction as SECINFO.		SECINFO_STYLE4_PARENT, which works in the opposite direction as SECINFO.
	As with <xref target="PUTFHplusLOOKUP" />, a put filehandle operation		As with <xref target="PUTFHplusLOOKUP" format="default"/>, a put filehandle operation
	that is followed by a LOOKUPP		that is followed by a LOOKUPP
	MUST NOT return NFS4ERR_WRONGSEC.		<bcp14>MUST NOT</bcp14> return NFS4ERR_WRONGSEC.
	If the server does not support SECINFO_NO_NAME, the client's		If the server does not support SECINFO_NO_NAME, the client's
	only recourse is to send the put filehandle operation,		only recourse is to send the put filehandle operation,
	LOOKUPP, GETFH sequence		LOOKUPP, GETFH sequence
	of operations with every security tuple it supports.		of operations with every security tuple it supports.
	</t>		</t>
	<t>		<t>
	Regardless of whether SECINFO_NO_NAME is supported, an		Regardless of whether SECINFO_NO_NAME is supported, an
	NFSv4.1 server MUST NOT return NFS4ERR_WRONGSEC in		NFSv4.1 server <bcp14>MUST NOT</bcp14> return NFS4ERR_WRONGSEC in
	response to a put filehandle operation if the		response to a put filehandle operation if the
	operation is immediately followed by a LOOKUPP.		operation is immediately followed by a LOOKUPP.
	</t>		</t>
	</section> <!-- PUTFH + LOOKUPP -->		</section>
	<section title="Put Filehandle Operation + SECINFO/SECINFO_NO_NAME"		<section anchor="PUTFHplusSECINFO" numbered="true" toc="default">
	anchor="PUTFHplusSECINFO">		<name>Put Filehandle Operation + SECINFO/SECINFO_NO_NAME</name>
	<t>		<t>
	A security-sensitive client is allowed to choose		A security-sensitive client is allowed to choose
	a strong security tuple when querying a server to		a strong security tuple when querying a server to
	determine a file object's permitted security tuples.		determine a file object's permitted security tuples.
	The security tuple chosen by the client does not have		The security tuple chosen by the client does not have
	to be included in the tuple list of the security policy		to be included in the tuple list of the security policy
	of either the parent directory indicated in the put filehandle		of either the parent directory indicated in the put filehandle
	operation or the child file object indicated in SECINFO (or any parent direc tory		operation or the child file object indicated in SECINFO (or any parent direc tory
	indicated in SECINFO_NO_NAME). Of course, the server has to be		indicated in SECINFO_NO_NAME). Of course, the server has to be
	configured for whatever security		configured for whatever security
	tuple the client selects; otherwise, the request will		tuple the client selects; otherwise, the request will
	fail at the RPC layer with an appropriate authentication error.		fail at the RPC layer with an appropriate authentication error.
	</t>		</t>
	<t>		<t>
	In theory, there is no connection between the security		In theory, there is no connection between the security
	flavor used by SECINFO or SECINFO_NO_NAME and those		flavor used by SECINFO or SECINFO_NO_NAME and those
	supported by the security policy. But in practice, the		supported by the security policy. But in practice, the
	client may start looking for strong flavors from those		client may start looking for strong flavors from those
	supported by the security policy, followed by those in		supported by the security policy, followed by those in
	the REQUIRED set.		the <bcp14>REQUIRED</bcp14> set.
	</t>		</t>
	<t>		<t>
	The NFSv4.1 server MUST NOT return NFS4ERR_WRONGSEC to a		The NFSv4.1 server <bcp14>MUST NOT</bcp14> return NFS4ERR_WRONGSEC to a
	put filehandle operation that		put filehandle operation that
	is immediately followed by SECINFO or SECINFO_NO_NAME.		is immediately followed by SECINFO or SECINFO_NO_NAME.
	The NFSv4.1 server MUST NOT return NFS4ERR_WRONGSEC from SECINFO or		The NFSv4.1 server <bcp14>MUST NOT</bcp14> return NFS4ERR_WRONGSEC from SECI NFO or
	SECINFO_NO_NAME.		SECINFO_NO_NAME.
	</t>		</t>
	</section> <!-- PUTFH + SECINFO -->		</section>
	<section anchor="PUTFHplusNothing" title="Put Filehandle Operation + Nothing"		<section anchor="PUTFHplusNothing" numbered="true" toc="default">
	>		<name>Put Filehandle Operation + Nothing</name>
	<t>		<t>
	The NFSv4.1 server MUST NOT return NFS4ERR_WRONGSEC.		The NFSv4.1 server <bcp14>MUST NOT</bcp14> return NFS4ERR_WRONGSEC.
	</t>		</t>
	</section> <!-- PUTFH + Nothing -->		</section>
	<section anchor="PUTFHplusAnythingElse" title="Put Filehandle Operation + Any		<section anchor="PUTFHplusAnythingElse" numbered="true" toc="default">
	thing Else">		<name>Put Filehandle Operation + Anything Else</name>
	<t>		<t>
	"Anything Else" includes OPEN by filehandle.		"Anything Else" includes OPEN by filehandle.
	</t>		</t>
	<t>		<t>
	The security policy enforcement applies to the		The security policy enforcement applies to the
	filehandle specified in the put filehandle operation. Therefore, the		filehandle specified in the put filehandle operation. Therefore, the
	put filehandle operation MUST		put filehandle operation <bcp14>MUST</bcp14>
	return NFS4ERR_WRONGSEC when there is a security tuple		return NFS4ERR_WRONGSEC when there is a security tuple
	mismatch. This avoids the complexity of		mismatch. This avoids the complexity of
	adding NFS4ERR_WRONGSEC as an allowable error to every		adding NFS4ERR_WRONGSEC as an allowable error to every
	other operation.		other operation.
	</t>		</t>
	<t>		<t>
	A COMPOUND containing the series put filehandle		A COMPOUND containing the series put filehandle
	operation + SECINFO_NO_NAME (style SECINFO_STYLE4_CURRENT_FH) is an		operation + SECINFO_NO_NAME (style SECINFO_STYLE4_CURRENT_FH) is an
	efficient way for the client to recover from		efficient way for the client to recover from
	NFS4ERR_WRONGSEC.		NFS4ERR_WRONGSEC.
	</t>		</t>
	<t>		<t>
	The NFSv4.1 server MUST NOT return NFS4ERR_WRONGSEC to		The NFSv4.1 server <bcp14>MUST NOT</bcp14> return NFS4ERR_WRONGSEC to
	any operation other than a put filehandle operation,		any operation other than a put filehandle operation,
	LOOKUP, LOOKUPP, and OPEN (by component name).		LOOKUP, LOOKUPP, and OPEN (by component name).
	</t>		</t>
	</section> <!-- PUTFH + Anything Else -->		</section>
	<section anchor="aftersecinfo" title="Operations after SECINFO and SECINFO_NO		<section anchor="aftersecinfo" numbered="true" toc="default">
	_NAME">		<name>Operations after SECINFO and SECINFO_NO_NAME</name>
	<t>		<t>
	Suppose a client sends a COMPOUND procedure		Suppose a client sends a COMPOUND procedure
	containing the series SEQUENCE, PUTFH,		containing the series SEQUENCE, PUTFH,
	SECINFO_NONAME, READ, and suppose the security tuple		SECINFO_NONAME, READ, and suppose the security tuple
	used does not match that required for the target		used does not match that required for the target
	file. By rule (see <xref target="PUTFHplusSECINFO"/>),		file. By rule (see <xref target="PUTFHplusSECINFO" format="default"/>),
	neither PUTFH nor SECINFO_NO_NAME can		neither PUTFH nor SECINFO_NO_NAME can
	return NFS4ERR_WRONGSEC. By rule (see <xref		return NFS4ERR_WRONGSEC. By rule (see <xref target="PUTFHplusAnythingElse"
	target="PUTFHplusAnythingElse"/>), READ cannot return		format="default"/>), READ cannot return
	NFS4ERR_WRONGSEC. The issue is resolved by the fact		NFS4ERR_WRONGSEC. The issue is resolved by the fact
	that SECINFO and SECINFO_NO_NAME consume the current		that SECINFO and SECINFO_NO_NAME consume the current
	filehandle (note that this is a change from NFSv4.0). This leaves no curren t filehandle for		filehandle (note that this is a change from NFSv4.0). This leaves no curren t filehandle for
	READ to use, and READ returns NFS4ERR_NOFILEHANDLE.		READ to use, and READ returns NFS4ERR_NOFILEHANDLE.
	</t>		</t>
			</section>
	</section> <!-- Operations after SECINFO and SECINFO_NO_NAME" -->
	</section>		</section>
	<section anchor="link_rename" title="LINK and RENAME" >		<section anchor="link_rename" numbered="true" toc="default">
	<t>		<name>LINK and RENAME</name>
			<t>
	The LINK and RENAME operations use both the current		The LINK and RENAME operations use both the current
	and saved filehandles.		and saved filehandles.
	Technically, the server MAY return NFS4ERR_WRONGSEC from		Technically, the server <bcp14>MAY</bcp14> return NFS4ERR_WRONGSEC from
	LINK or RENAME		LINK or RENAME
	if the security policy of the		if the security policy of the
	saved filehandle rejects the security flavor used in the		saved filehandle rejects the security flavor used in the
	COMPOUND request's credentials. If the server does so,		COMPOUND request's credentials. If the server does so,
	then if there is no intersection between the security		then if there is no intersection between the security
	policies of saved and current filehandles, this means that it		policies of saved and current filehandles, this means that it
	will be impossible for the client to perform the intended		will be impossible for the client to perform the intended
	LINK or RENAME operation.		LINK or RENAME operation.
	</t>		</t>
	<t>		<t>
	For example, suppose the client sends this COMPOUND		For example, suppose the client sends this COMPOUND
	request: SEQUENCE, PUTFH bFH, SAVEFH, PUTFH aFH,		request: SEQUENCE, PUTFH bFH, SAVEFH, PUTFH aFH,
	RENAME "c" "d", where filehandles bFH and aFH refer		RENAME "c" "d", where filehandles bFH and aFH refer
	to different directories. Suppose no common security		to different directories. Suppose no common security
	tuple exists between the security policies of aFH and		tuple exists between the security policies of aFH and
	bFH. If the client sends the request using credentials		bFH. If the client sends the request using credentials
	acceptable to bFH's security policy but not aFH's		acceptable to bFH's security policy but not aFH's
	policy, then the PUTFH aFH operation will fail with		policy, then the PUTFH aFH operation will fail with
	NFS4ERR_WRONGSEC. After a SECINFO_NO_NAME request,		NFS4ERR_WRONGSEC. After a SECINFO_NO_NAME request,
	the client sends SEQUENCE, PUTFH bFH, SAVEFH, PUTFH		the client sends SEQUENCE, PUTFH bFH, SAVEFH, PUTFH
	aFH, RENAME "c" "d", using credentials acceptable to		aFH, RENAME "c" "d", using credentials acceptable to
	aFH's security policy but not bFH's policy. The server		aFH's security policy but not bFH's policy. The server
	returns NFS4ERR_WRONGSEC on the RENAME operation.		returns NFS4ERR_WRONGSEC on the RENAME operation.
	</t>		</t>
	<t>		<t>
	To prevent a client from an endless sequence of a		To prevent a client from an endless sequence of a
	request containing LINK or RENAME, followed by a request		request containing LINK or RENAME, followed by a request
	containing SECINFO_NO_NAME or SECINFO, the server MUST detect		containing SECINFO_NO_NAME or SECINFO, the server <bcp14>MUST</bcp14> detect
	when the security policies of the current and saved		when the security policies of the current and saved
	filehandles have no mutually acceptable security tuple,		filehandles have no mutually acceptable security tuple,
	and MUST NOT return NFS4ERR_WRONGSEC from LINK or RENAME		and <bcp14>MUST NOT</bcp14> return NFS4ERR_WRONGSEC from LINK or RENAME
	in that situation. Instead		in that situation. Instead
	the server MUST do one of two things:		the server <bcp14>MUST</bcp14> do one of two things:
	<list style='symbols'>		</t>
			<ul spacing="normal">
	<t>		<li>
	The server can return NFS4ERR_XDEV.		The server can return NFS4ERR_XDEV.
	</t>		</li>
			<li>
	<t>
	The server can		The server can
	allow the security policy of the current filehandle to		allow the security policy of the current filehandle to
	override that of the saved filehandle, and so return NFS4_OK.		override that of the saved filehandle, and so return NFS4_OK.
	</t>		</li>
			</ul>
	</list>		</section>
			</section>
	</t>		</section>
	</section>		</section>
	</section> <!-- Using NFS4ERR_WRONGSEC, SECINFO, and SECINFO_NO_NAME -->
	</section> <!-- Security Error -->
	</section> <!-- Security Service Negotiation -->
	<section anchor="minor_versioning" title="Minor Versioning">		<section anchor="minor_versioning" numbered="true" toc="default">
	<t>		<name>Minor Versioning</name>
			<t>
	To address the requirement of an NFS protocol that can evolve as the		To address the requirement of an NFS protocol that can evolve as the
	need arises, the NFSv4.1 protocol contains the rules and		need arises, the NFSv4.1 protocol contains the rules and
	framework to allow for future minor changes or versioning.		framework to allow for future minor changes or versioning.
	</t>		</t>
	<t>		<t>
	The base assumption with respect to minor versioning is that any		The base assumption with respect to minor versioning is that any
	future accepted minor version will be		future accepted minor version will be
	documented in one or more Standards Track RFCs.		documented in one or more Standards Track RFCs.
	Minor version 0 of the NFSv4 protocol is represented by		Minor version 0 of the NFSv4 protocol is represented by
	<xref target="RFC3530" />, and minor version 1 is represented by		<xref target="RFC3530" format="default"/>, and minor version 1 is represented by
	this RFC.		this RFC.
	The COMPOUND and CB_COMPOUND		The COMPOUND and CB_COMPOUND
	procedures support the encoding of the minor version		procedures support the encoding of the minor version
	being requested by the client.		being requested by the client.
	</t>		</t>
	<t>		<t>
	The following items represent the basic rules for the development of		The following items represent the basic rules for the development of
	minor versions. Note that a future minor version may modify		minor versions. Note that a future minor version may modify
	or add to the following rules as part of the minor version definition.		or add to the following rules as part of the minor version definition.
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
			<t>
	Procedures are not added or deleted.		Procedures are not added or deleted.
	<vspace blankLines='1' />		</t>
			<t>
	To maintain the general RPC model, NFSv4 minor versions will		To maintain the general RPC model, NFSv4 minor versions will
	not add to or delete procedures from the NFS program.		not add to or delete procedures from the NFS program.
	</t>		</t>
			</li>
	<t>		<li>
			<t>
	Minor versions may add operations to the COMPOUND and CB_COMPOUND		Minor versions may add operations to the COMPOUND and CB_COMPOUND
	procedures.		procedures.
	<vspace blankLines='1' />		</t>
			<t>
	The addition of operations to the COMPOUND and CB_COMPOUND procedures		The addition of operations to the COMPOUND and CB_COMPOUND procedures
	does not affect the RPC model.		does not affect the RPC model.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	Minor versions may append attributes to the bitmap4 that represents		Minor versions may append attributes to the bitmap4 that represents
	sets of attributes and to the fattr4 that represents sets of attribute		sets of attributes and to the fattr4 that represents sets of attribute
	values.		values.
	<vspace blankLines='1' />		</t>
			<t>
	This allows for the expansion of the attribute model to allow for		This allows for the expansion of the attribute model to allow for
	future growth or adaptation.		future growth or adaptation.
	</t>		</t>
			</li>
	<t>		<li>
			<t>
	Minor version X must append any new attributes after the last		Minor version X must append any new attributes after the last
	documented attribute.		documented attribute.
	<vspace blankLines='1' />		</t>
			<t>
	Since attribute results are specified as an opaque array of		Since attribute results are specified as an opaque array of
	per-attribute, XDR-encoded results, the complexity of adding new		per-attribute, XDR-encoded results, the complexity of adding new
	attributes in the midst of the current definitions would be too		attributes in the midst of the current definitions would be too
	burdensome.		burdensome.
	</t>		</t>
	</list>		</li>
	</t>		</ul>
			</li>
	<t>		<li>
			<t>
	Minor versions must not modify the structure of an existing		Minor versions must not modify the structure of an existing
	operation's arguments or results.		operation's arguments or results.
	<vspace blankLines='1' />		</t>
			<t>
	Again, the complexity of handling multiple structure definitions for a		Again, the complexity of handling multiple structure definitions for a
	single operation is too burdensome. New operations should be added		single operation is too burdensome. New operations should be added
	instead of modifying existing structures for a minor version.		instead of modifying existing structures for a minor version.
	<vspace blankLines='1' />		</t>
			<t>
	This rule does not preclude the following adaptations in a minor version:		This rule does not preclude the following adaptations in a minor version:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	adding bits to flag fields, such as new attributes to GETATTR's bitmap4		adding bits to flag fields, such as new attributes to GETATTR's bitmap4
	data type, and providing corresponding variants of opaque arrays,		data type, and providing corresponding variants of opaque arrays,
	such as a notify4 used together with such bitmaps		such as a notify4 used together with such bitmaps
	</t>		</li>
	<t>		<li>
	adding bits to existing attributes like ACLs that have flag words		adding bits to existing attributes like ACLs that have flag words
	</t>		</li>
	<t>		<li>
	extending enumerated types (including NFS4ERR_*) with new values		extending enumerated types (including NFS4ERR_*) with new values
	</t>		</li>
	<t>		<li>
	adding cases to a switched union		adding cases to a switched union
	</t>		</li>
	</list>		</ul>
	</t>		</li>
			<li>
	<t>
	Minor versions must not modify the structure of existing attributes.		Minor versions must not modify the structure of existing attributes.
	</t>		</li>
			<li>
	<t>		<t>
	Minor versions must not delete operations.		Minor versions must not delete operations.
	<vspace blankLines='1' />		</t>
			<t>
	This prevents the potential reuse of a particular operation "slot" in		This prevents the potential reuse of a particular operation "slot" in
	a future minor version.		a future minor version.
	</t>		</t>
			</li>
	<t>		<li>
	Minor versions must not delete attributes.		Minor versions must not delete attributes.
	</t>		</li>
			<li>
	<t>
	Minor versions must not delete flag bits or enumeration values.		Minor versions must not delete flag bits or enumeration values.
	</t>		</li>
			<li>
	<t>		<t>
	Minor versions may declare an operation MUST NOT be implemented.		Minor versions may declare an operation <bcp14>MUST NOT</bcp14> be implemented.
	<vspace blankLines='1' />		</t>
	Specifying that an operation MUST NOT be implemented is equivalent		<t>
			Specifying that an operation <bcp14>MUST NOT</bcp14> be implemented is equivale
			nt
	to obsoleting an operation. For the client, it means that the		to obsoleting an operation. For the client, it means that the
	operation MUST NOT be sent to the server. For the server, an NFS		operation <bcp14>MUST NOT</bcp14> be sent to the server. For the server, an NF S
	error can be returned as opposed to "dropping" the request as an XDR		error can be returned as opposed to "dropping" the request as an XDR
	decode error. This approach allows for the obsolescence of an		decode error. This approach allows for the obsolescence of an
	operation while maintaining its structure so that a future minor version can re introduce the operation.		operation while maintaining its structure so that a future minor version can re introduce the operation.
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
	Minor versions may declare that an attribute MUST NOT be implemented.		<li>
	</t>		Minor versions may declare that an attribute <bcp14>MUST NOT</bcp14> be impleme
	<t>		nted.
	Minor versions may declare that a flag bit or enumeration value MUST NOT		</li>
			<li>
			Minor versions may declare that a flag bit or enumeration value <bcp14>MUST NOT
			</bcp14>
	be implemented.		be implemented.
	</t>		</li>
	</list>		</ol>
	</t>		</li>
			<li>
	<t>		Minor versions may downgrade features from <bcp14>REQUIRED</bcp14> to <bcp14>RE
	Minor versions may downgrade features from REQUIRED to RECOMMENDED,		COMMENDED</bcp14>,
	or RECOMMENDED to OPTIONAL.		or <bcp14>RECOMMENDED</bcp14> to <bcp14>OPTIONAL</bcp14>.
	</t>		</li>
			<li>
	<t>		Minor versions may upgrade features from <bcp14>OPTIONAL</bcp14> to <bcp14>RECO
	Minor versions may upgrade features from OPTIONAL to RECOMMENDED, or		MMENDED</bcp14>, or
	RECOMMENDED to REQUIRED.		<bcp14>RECOMMENDED</bcp14> to <bcp14>REQUIRED</bcp14>.
	</t>		</li>
			<li>
	<t>		A client and server that support minor version X <bcp14>SHOULD</bcp14> support
	A client and server that support minor version X SHOULD support minor		minor
	versions zero through X-1 as well.		versions zero through X-1 as well.
	</t>		</li>
			<li>
	<t>		<t>
	Except for infrastructural changes, a minor version must not		Except for infrastructural changes, a minor version must not
	introduce REQUIRED new features.		introduce <bcp14>REQUIRED</bcp14> new features.
	<vspace blankLines='1' />		</t>
			<t>
	This rule allows for the introduction of new functionality and forces		This rule allows for the introduction of new functionality and forces
	the use of implementation experience before designating a feature as		the use of implementation experience before designating a feature as
	REQUIRED. On the other hand, some classes of features are		<bcp14>REQUIRED</bcp14>. On the other hand, some classes of features are
	infrastructural and have broad effects. Allowing infrastructural features		infrastructural and have broad effects. Allowing infrastructural features
	to be RECOMMENDED or OPTIONAL complicates implementation of the minor version.		to be <bcp14>RECOMMENDED</bcp14> or <bcp14>OPTIONAL</bcp14> complicates impleme
	</t>		ntation of the minor version.
			</t>
	<t>		</li>
	A client MUST NOT attempt to use a stateid, filehandle, or similar		<li>
			A client <bcp14>MUST NOT</bcp14> attempt to use a stateid, filehandle, or simil
			ar
	returned object from the COMPOUND procedure with minor version X for		returned object from the COMPOUND procedure with minor version X for
	another COMPOUND procedure with minor version Y, where X != Y.		another COMPOUND procedure with minor version Y, where X != Y.
	</t>		</li>
	</list>		</ol>
	</t>		</section>
	</section> <!-- Minor Versioning -->
	<section anchor="Non-RPC-based_Security_Services" title="Non-RPC-Based Security		<section anchor="Non-RPC-based_Security_Services" numbered="true" toc="default"
	Services">		>
	<t>		<name>Non-RPC-Based Security Services</name>
	As described in		<t>
	<xref target="Authentication_Integrity_Privacy" />,		As described in <xref target="Authentication_Integrity_Privacy" format="defaul
			t"/>,
	NFSv4.1 relies on RPC for identification,		NFSv4.1 relies on RPC for identification,
	authentication, integrity, and privacy. NFSv4.1 itself		authentication, integrity, and privacy. NFSv4.1 itself
	provides or enables additional security services as described in the		provides or enables additional security services as described in the
	next several subsections.		next several subsections.
	</t>		</t>
			<section anchor="Authorization" numbered="true" toc="default">
	<section anchor="Authorization" title="Authorization">		<name>Authorization</name>
	<t>		<t>
	Authorization to access a file object via an NFSv4.1		Authorization to access a file object via an NFSv4.1
	operation is ultimately determined by the NFSv4.1		operation is ultimately determined by the NFSv4.1
	server. A client can predetermine its access to a file		server. A client can predetermine its access to a file
	object via the OPEN (<xref target="OP_OPEN" />)		object via the OPEN (<xref target="OP_OPEN" format="default"/>)
	and the ACCESS (<xref target="OP_ACCESS" />)		and the ACCESS (<xref target="OP_ACCESS" format="default"/>)
	operations.		operations.
	</t>		</t>
	<t>		<t>
	Principals with appropriate access rights can modify the		Principals with appropriate access rights can modify the
	authorization on a file object via the SETATTR		authorization on a file object via the SETATTR
	(<xref target="OP_SETATTR" />) operation. Attributes that affect		(<xref target="OP_SETATTR" format="default"/>) operation. Attributes that af fect
	access rights include mode, owner, owner_group, acl, dacl, and		access rights include mode, owner, owner_group, acl, dacl, and
	sacl. See <xref target="file_attributes" />.		sacl. See <xref target="file_attributes" format="default"/>.
	</t>		</t>
	</section> <!-- Authorization -->		</section>
	<section anchor="Auditing" title="Auditing">		<section anchor="Auditing" numbered="true" toc="default">
	<t>		<name>Auditing</name>
			<t>
	NFSv4.1 provides auditing on a per-file object basis, via the acl		NFSv4.1 provides auditing on a per-file object basis, via the acl
	and sacl attributes as described in <xref target="acl" />. It is		and sacl attributes as described in <xref target="acl" format="default"/>. I t is
	outside the scope of this specification to specify audit log		outside the scope of this specification to specify audit log
	formats or management policies.		formats or management policies.
	</t>		</t>
	</section> <!-- Auditing -->		</section>
	<section anchor="Intrusion_Detection" title="Intrusion Detection">		<section anchor="Intrusion_Detection" numbered="true" toc="default">
	<t>		<name>Intrusion Detection</name>
			<t>
	NFSv4.1 provides alarm control on a per-file object basis, via the		NFSv4.1 provides alarm control on a per-file object basis, via the
	acl and sacl attributes as described in <xref target="acl" />.		acl and sacl attributes as described in <xref target="acl" format="default"/> .
	Alarms may serve as the basis for intrusion detection. It is		Alarms may serve as the basis for intrusion detection. It is
	outside the scope of this specification to specify heuristics for		outside the scope of this specification to specify heuristics for
	detecting intrusion via alarms.		detecting intrusion via alarms.
	</t>		</t>
	</section> <!-- Intrusion Detection -->		</section>
	</section> <!-- Non-RPC-based Security Services -->		</section>
	<section anchor="Transport_Layers" title="Transport Layers">
	<section anchor="Required_and_Recommended_Transport_Attributes"		<section anchor="Transport_Layers" numbered="true" toc="default">
	title="REQUIRED and RECOMMENDED Properties of Transports">		<name>Transport Layers</name>
	<t>		<section anchor="Required_and_Recommended_Transport_Attributes" numbered
			="true" toc="default">
			<name><bcp14>REQUIRED</bcp14> and <bcp14>RECOMMENDED</bcp14> Propertie
			s of Transports</name>
			<t>
	NFSv4.1 works over Remote Direct Memory Access (RDMA) and non-RDMA-based tran sports with		NFSv4.1 works over Remote Direct Memory Access (RDMA) and non-RDMA-based tran sports with
	the following attributes:		the following attributes:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	The transport supports reliable delivery of data, which		The transport supports reliable delivery of data, which
	NFSv4.1 requires but neither NFSv4.1 nor RPC has facilities		NFSv4.1 requires but neither NFSv4.1 nor RPC has facilities
	for ensuring <xref target="Chet" />.		for ensuring <xref target="Chet" format="default"/>.
	</t>		</li>
	<t>		<li>
	The transport delivers data in the order it was sent.		The transport delivers data in the order it was sent.
	Ordered delivery simplifies detection of transmit		Ordered delivery simplifies detection of transmit
	errors, and simplifies the sending of arbitrary sized		errors, and simplifies the sending of arbitrary sized
	requests and responses via the record marking		requests and responses via the record marking
	protocol <xref target="RFC5531" />.		protocol <xref target="RFC5531" format="default"/>.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Where an NFSv4.1 implementation supports operation		Where an NFSv4.1 implementation supports operation
	over the IP network protocol, any transport used between		over the IP network protocol, any transport used between
	NFS and IP MUST be among the IETF-approved congestion		NFS and IP <bcp14>MUST</bcp14> be among the IETF-approved congestion
	control transport protocols. At the time this document		control transport protocols. At the time this document
	was written, the only two transports that had the above		was written, the only two transports that had the above
	attributes were TCP and the Stream		attributes were TCP and the Stream
	Control Transmission Protocol (SCTP). To enhance the		Control Transmission Protocol (SCTP). To enhance the
	possibilities for interoperability, an NFSv4.1		possibilities for interoperability, an NFSv4.1
	implementation MUST support operation over the TCP		implementation <bcp14>MUST</bcp14> support operation over the TCP
	transport protocol.		transport protocol.
	</t>		</t>
	<t>		<t>
	Even if NFSv4.1 is used over a non-IP network		Even if NFSv4.1 is used over a non-IP network
	protocol, it is RECOMMENDED that the transport support		protocol, it is <bcp14>RECOMMENDED</bcp14> that the transport support
	congestion control.		congestion control.
	</t>		</t>
	<t>		<t>
	It is permissible for a connectionless transport to		It is permissible for a connectionless transport to
	be used under NFSv4.1; however, reliable and in-order		be used under NFSv4.1; however, reliable and in-order
	delivery of data combined with congestion control		delivery of data combined with congestion control
	by the connectionless transport is		by the connectionless transport is
	REQUIRED. As a consequence, UDP by itself MUST NOT be used		<bcp14>REQUIRED</bcp14>. As a consequence, UDP by itself <bcp14>MUST NOT</bc p14> be used
	as an NFSv4.1 transport. NFSv4.1 assumes that a client transport		as an NFSv4.1 transport. NFSv4.1 assumes that a client transport
	address and server transport address used to send data		address and server transport address used to send data
	over a transport together constitute a connection,		over a transport together constitute a connection,
	even if the underlying transport eschews the concept		even if the underlying transport eschews the concept
	of a connection.		of a connection.
	</t>		</t>
	</section> <!-- Required and Recommended Transport Attributes -->		</section>
	<section anchor="Client_and_Server_Transport_Behavior" title="Client and Serve		<section anchor="Client_and_Server_Transport_Behavior" numbered="true" toc="de
	r Transport Behavior">		fault">
	<t>		<name>Client and Server Transport Behavior</name>
			<t>
	If a connection-oriented transport (e.g., TCP) is used,		If a connection-oriented transport (e.g., TCP) is used,
	the client and server SHOULD use long-lived connections		the client and server <bcp14>SHOULD</bcp14> use long-lived connections
	for at least three reasons:		for at least three reasons:
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	This will prevent the weakening of the transport's		This will prevent the weakening of the transport's
	congestion control mechanisms via short-lived		congestion control mechanisms via short-lived
	connections.		connections.
	</t>		</li>
	<t>		<li>
	This will improve performance for the WAN environment		This will improve performance for the WAN environment
	by eliminating the need for connection setup		by eliminating the need for connection setup
	handshakes.		handshakes.
	</t>		</li>
	<t>		<li>
	The NFSv4.1 callback model differs from NFSv4.0, and		The NFSv4.1 callback model differs from NFSv4.0, and
	requires the client and server to maintain a		requires the client and server to maintain a
	client-created backchannel (see <xref target="conn_chann_assoc" />) for the		client-created backchannel (see <xref target="conn_chann_assoc" format="defa
	server to use.		ult"/>) for the server to use.
	</t>		</li>
	</list>		</ol>
	</t>		<t>
	<t>
	In order to reduce congestion, if a connection-oriented		In order to reduce congestion, if a connection-oriented
	transport is used, and the request is not the NULL		transport is used, and the request is not the NULL
	procedure:		procedure:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
	A requester MUST		<li>
	NOT retry a request unless the connection the request		A requester <bcp14>MUST NOT</bcp14> retry a request unless the connection th
			e request
	was sent over was lost before the reply was		was sent over was lost before the reply was
	received.		received.
	</t>		</li>
	<t>		<li>
	A replier MUST		A replier <bcp14>MUST
	NOT silently drop a request, even if the request is a		NOT</bcp14> silently drop a request, even if the request is a
	retry. (The silent drop behavior of RPCSEC_GSS		retry. (The silent drop behavior of RPCSEC_GSS
	<xref target="RFC2203" /> does not apply		<xref target="RFC2203" format="default"/> does not apply
	because this behavior happens at the RPCSEC_GSS layer,		because this behavior happens at the RPCSEC_GSS layer,
	a lower layer in the request processing.) Instead, the		a lower layer in the request processing.) Instead, the
	replier SHOULD return an appropriate error (see		replier <bcp14>SHOULD</bcp14> return an appropriate error (see
	<xref target="Slot_Identifiers_and_Server_Reply_Cache" />),		<xref target="Slot_Identifiers_and_Server_Reply_Cache" format="default"/>),
	or it MAY disconnect the connection.		or it <bcp14>MAY</bcp14> disconnect the connection.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	When sending a reply, the replier MUST send the reply		When sending a reply, the replier <bcp14>MUST</bcp14> send the reply
	to the same full network address (e.g., if using an		to the same full network address (e.g., if using an
	IP-based transport, the source port of the requester		IP-based transport, the source port of the requester
	is part of the full network address) from which the requester		is part of the full network address) from which the requester
	sent the request. If using a connection-oriented		sent the request. If using a connection-oriented
	transport, replies MUST be sent on the same connection from which		transport, replies <bcp14>MUST</bcp14> be sent on the same connection from w hich
	the request was received.		the request was received.
	</t>		</t>
			<t>
	<t>
	If a connection is dropped after the replier receives		If a connection is dropped after the replier receives
	the request but before the replier sends the reply, the		the request but before the replier sends the reply, the
	replier might have a pending reply.		replier might have a pending reply.
	If a connection is established with the same		If a connection is established with the same
	source and destination full network address as the		source and destination full network address as the
	dropped connection, then the replier MUST NOT send		dropped connection, then the replier <bcp14>MUST NOT</bcp14> send
	the reply until the requester retries the request. The		the reply until the requester retries the request. The
	reason for this prohibition is that the requester MAY		reason for this prohibition is that the requester <bcp14>MAY</bcp14>
	retry a request over a different connection (provided that connection		retry a request over a different connection (provided that connection
	is associated with the original request's session).		is associated with the original request's session).
	</t>		</t>
			<t>
	<t>
	When using RDMA transports, there are other reasons for not		When using RDMA transports, there are other reasons for not
	tolerating retries over the same connection:		tolerating retries over the same connection:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	RDMA transports use "credits" to enforce flow control, where		RDMA transports use "credits" to enforce flow control, where
	a credit is a right to a peer to transmit a message.		a credit is a right to a peer to transmit a message.
	If one peer were to retransmit a request (or reply), it would		If one peer were to retransmit a request (or reply), it would
	consume an additional credit.		consume an additional credit.
	If the replier		If the replier
	retransmitted a reply, it would certainly result in an RDMA		retransmitted a reply, it would certainly result in an RDMA
	connection loss, since the requester would typically only post a		connection loss, since the requester would typically only post a
	single receive buffer for each request. If the requester		single receive buffer for each request. If the requester
	retransmitted a request, the additional credit consumed on the		retransmitted a request, the additional credit consumed on the
	server might lead to RDMA connection failure unless the client		server might lead to RDMA connection failure unless the client
	accounted for it and decreased its available credit, leading to		accounted for it and decreased its available credit, leading to
	wasted resources.		wasted resources.
	</t>		</li>
	<t>		<li>
	RDMA credits present a new issue to the reply cache in		RDMA credits present a new issue to the reply cache in
	NFSv4.1. The reply cache may be used when a connection within a		NFSv4.1. The reply cache may be used when a connection within a
	session is lost, such as after the client reconnects. Credit		session is lost, such as after the client reconnects. Credit
	information is a dynamic property of the RDMA connection, and stale		information is a dynamic property of the RDMA connection, and stale
	values must not be replayed from the cache. This implies that the		values must not be replayed from the cache. This implies that the
	reply cache contents must not be blindly used when replies are		reply cache contents must not be blindly used when replies are
	sent from it, and credit information appropriate to the channel		sent from it, and credit information appropriate to the channel
	must be refreshed by the RPC layer.		must be refreshed by the RPC layer.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	In addition, as described in		In addition, as described in
	<xref target="Retry_and_Replay" />, while a session is active,		<xref target="Retry_and_Replay" format="default"/>, while a session is active
	the NFSv4.1 requester MUST NOT stop waiting for a reply.		,
	</t>		the NFSv4.1 requester <bcp14>MUST NOT</bcp14> stop waiting for a reply.
	</section> <!-- Client and Server Transport Behavior -->		</t>
			</section>
	<section anchor="Ports" title="Ports">		<section anchor="Ports" numbered="true" toc="default">
	<t>		<name>Ports</name>
			<t>
	Historically, NFSv3 servers have listened over		Historically, NFSv3 servers have listened over
	TCP port 2049. The registered port 2049 <xref target="RFC3232"/>		TCP port 2049. The registered port 2049 <xref target="RFC3232" format="defau lt"/>
	for the NFS protocol should be the default configuration. NFSv4.1		for the NFS protocol should be the default configuration. NFSv4.1
	clients SHOULD NOT use the RPC binding protocols as described in		clients <bcp14>SHOULD NOT</bcp14> use the RPC binding protocols as described
	<xref target="RFC1833"/>.		in
	</t>		<xref target="RFC1833" format="default"/>.
	</section> <!-- Ports -->		</t>
			</section>
	</section> <!-- Transport Layers -->		</section>
	<section anchor="Session" title="Session">		<section anchor="Session" numbered="true" toc="default">
	<t>		<name>Session</name>
	NFSv4.1 clients and servers MUST support and MUST use the session		<t>
			NFSv4.1 clients and servers <bcp14>MUST</bcp14> support and <bcp14>MUST</bcp1
			4> use the session
	feature as described in this section.		feature as described in this section.
	</t>		</t>
			<section anchor="Motivation_and_Overview" numbered="true" toc="default">
	<section anchor="Motivation_and_Overview" title="Motivation and Overview">		<name>Motivation and Overview</name>
	<t>		<t>
	Previous versions and minor versions of NFS have suffered from		Previous versions and minor versions of NFS have suffered from
	the following:		the following:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	Lack of support for Exactly Once Semantics (EOS). This includes		Lack of support for Exactly Once Semantics (EOS). This includes
	lack of support for EOS through server failure and recovery.		lack of support for EOS through server failure and recovery.
	</t>		</li>
	<t>		<li>
	Limited callback support, including no support for sending callbacks		Limited callback support, including no support for sending callbacks
	through firewalls, and races between replies to normal requests		through firewalls, and races between replies to normal requests
	and callbacks.		and callbacks.
	</t>		</li>
	<t>		<li>
	Limited trunking over multiple network paths.		Limited trunking over multiple network paths.
	</t>		</li>
	<t>		<li>
	Requiring machine credentials for fully secure operation.		Requiring machine credentials for fully secure operation.
	</t>		</li>
	</list>		</ul>
			<t>
	Through the introduction of a session, NFSv4.1 addresses the		Through the introduction of a session, NFSv4.1 addresses the
	above shortfalls with practical solutions:		above shortfalls with practical solutions:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	EOS is enabled by a reply cache with a bounded size,		EOS is enabled by a reply cache with a bounded size,
	making it feasible to keep the cache in persistent storage and enable		making it feasible to keep the cache in persistent storage and enable
	EOS through server failure and recovery. One reason that		EOS through server failure and recovery. One reason that
	previous revisions of NFS did not support EOS was		previous revisions of NFS did not support EOS was
	because some EOS approaches often limited parallelism.		because some EOS approaches often limited parallelism.
	As will be explained in		As will be explained in
	<xref target="Exactly_Once_Semantics" />,		<xref target="Exactly_Once_Semantics" format="default"/>,
	NFSv4.1 supports both EOS and unlimited parallelism.		NFSv4.1 supports both EOS and unlimited parallelism.
	</t>		</li>
	<t>		<li>
	The NFSv4.1 client (defined in <xref target="intro_definitions" />,		The NFSv4.1 client (defined in <xref target="client_def" format="default"/>)
	<xref target="client_def"/>) creates transport		creates transport
	connections and provides them to the server to use for sending		connections and provides them to the server to use for sending
	callback requests, thus solving the firewall issue		callback requests, thus solving the firewall issue
	(<xref target="OP_BIND_CONN_TO_SESSION" />). Races between		(<xref target="OP_BIND_CONN_TO_SESSION" format="default"/>). Races between
	responses from client requests and callbacks caused by		responses from client requests and callbacks caused by
	the requests are detected via the session's sequencing		the requests are detected via the session's sequencing
	properties that are a consequence of EOS		properties that are a consequence of EOS
	(<xref target="sessions_callback_races" />).		(<xref target="sessions_callback_races" format="default"/>).
	</t>		</li>
	<t>		<li>
	The NFSv4.1 client can associate an arbitrary number of connections with		The NFSv4.1 client can associate an arbitrary number of connections with
	the session, and thus provide trunking (<xref target="Trunking" />).		the session, and thus provide trunking (<xref target="Trunking" format="defa
	</t>		ult"/>).
	<t>		</li>
			<li>
	The NFSv4.1 client and server produce a session key independent of client		The NFSv4.1 client and server produce a session key independent of client
	and server machine credentials which can be		and server machine credentials which can be
	used to compute a digest for protecting critical session management operatio ns		used to compute a digest for protecting critical session management operatio ns
	(<xref target="protect_state_change" />).		(<xref target="protect_state_change" format="default"/>).
	</t>		</li>
	<t>		<li>
	The NFSv4.1 client can also create secure RPCSEC_GSS contexts		The NFSv4.1 client can also create secure RPCSEC_GSS contexts
	for use by the session's backchannel that do not require		for use by the session's backchannel that do not require
	the server to authenticate to a client machine principal		the server to authenticate to a client machine principal
	(<xref target="Backchannel_RPC_Security" />).		(<xref target="Backchannel_RPC_Security" format="default"/>).
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	A session is a dynamically created, long-lived server object		A session is a dynamically created, long-lived server object
	created by a client and used over time from one or more transport		created by a client and used over time from one or more transport
	connections. Its function is to maintain the server's state		connections. Its function is to maintain the server's state
	relative to the connection(s) belonging to a client instance. This		relative to the connection(s) belonging to a client instance. This
	state is entirely independent of the connection itself, and indeed		state is entirely independent of the connection itself, and indeed
	the state exists whether or not the connection exists. A client may		the state exists whether or not the connection exists. A client may
	have one or more sessions associated with it so that		have one or more sessions associated with it so that
	client-associated state may be accessed using any of the sessions		client-associated state may be accessed using any of the sessions
	associated with that client's client ID, when connections are		associated with that client's client ID, when connections are
	associated with those sessions. When no connections are associated		associated with those sessions. When no connections are associated
	with any of a client ID's sessions for an extended time, such		with any of a client ID's sessions for an extended time, such
	objects as locks, opens, delegations, layouts, etc. are subject to		objects as locks, opens, delegations, layouts, etc. are subject to
	expiration. The session serves as an object representing a means		expiration. The session serves as an object representing a means
	of access by a client to the associated client state on the server,		of access by a client to the associated client state on the server,
	independent of the physical means of access to that state.		independent of the physical means of access to that state.
	</t>		</t>
	<t>		<t>
	A single client may create multiple sessions. A single session MUST		A single client may create multiple sessions. A single session <bcp14>MUST
	NOT serve multiple clients.		NOT</bcp14> serve multiple clients.
	</t>		</t>
	</section> <!-- Motivation and Overview -->		</section>
	<section anchor="NFSv4_Integration" title="NFSv4 Integration">		<section anchor="NFSv4_Integration" numbered="true" toc="default">
	<t>		<name>NFSv4 Integration</name>
			<t>
	Sessions are part of NFSv4.1 and not NFSv4.0. Normally, a major		Sessions are part of NFSv4.1 and not NFSv4.0. Normally, a major
	infrastructure change such as sessions would require a new major		infrastructure change such as sessions would require a new major
	version number to an Open Network Computing (ONC) RPC program like		version number to an Open Network Computing (ONC) RPC program like
	NFS. However, because NFSv4 encapsulates its functionality in a single proced ure, COMPOUND,		NFS. However, because NFSv4 encapsulates its functionality in a single proced ure, COMPOUND,
	and because COMPOUND can support an arbitrary number of		and because COMPOUND can support an arbitrary number of
	operations, sessions have been added to NFSv4.1 with little difficulty. COMPO UND includes		operations, sessions have been added to NFSv4.1 with little difficulty. COMPO UND includes
	a minor version number field, and for NFSv4.1 this minor version		a minor version number field, and for NFSv4.1 this minor version
	is set to 1. When the NFSv4 server processes a COMPOUND with		is set to 1. When the NFSv4 server processes a COMPOUND with
	the minor version set to 1, it expects a different set of		the minor version set to 1, it expects a different set of
	operations than it does for NFSv4.0. NFSv4.1 defines the		operations than it does for NFSv4.0. NFSv4.1 defines the
	SEQUENCE operation, which is required for every		SEQUENCE operation, which is required for every
	COMPOUND that operates over an established session, with the		COMPOUND that operates over an established session, with the
	exception of some session administration operations, such		exception of some session administration operations, such
	as DESTROY_SESSION (<xref target="OP_DESTROY_SESSION" />).		as DESTROY_SESSION (<xref target="OP_DESTROY_SESSION" format="default"/>).
	</t>		</t>
			<section anchor="SEQUENCE_and_CB_SEQUENCE" numbered="true" toc="defaul
	<section anchor="SEQUENCE_and_CB_SEQUENCE" title="SEQUENCE and CB_SEQUENCE">		t">
	<t>		<name>SEQUENCE and CB_SEQUENCE</name>
	In NFSv4.1, when the SEQUENCE operation is present, it MUST be		<t>
			In NFSv4.1, when the SEQUENCE operation is present, it <bcp14>MUST</bcp14>
			be
	the first operation in the COMPOUND procedure. The primary purpose		the first operation in the COMPOUND procedure. The primary purpose
	of SEQUENCE is to carry the session identifier. The session identifier		of SEQUENCE is to carry the session identifier. The session identifier
	associates all other operations in the COMPOUND procedure with		associates all other operations in the COMPOUND procedure with
	a particular session. SEQUENCE also contains required information		a particular session. SEQUENCE also contains required information
	for maintaining EOS (see <xref target="Exactly_Once_Semantics" />).		for maintaining EOS (see <xref target="Exactly_Once_Semantics" format="defa ult"/>).
	Session-enabled NFSv4.1 COMPOUND requests thus have the form:		Session-enabled NFSv4.1 COMPOUND requests thus have the form:
	</t>		</t>
	<figure>		<artwork name="" type="" align="left" alt=""><![CDATA[
	<artwork>
	+-----+--------------+-----------+------------+-----------+----		+-----+--------------+-----------+------------+-----------+----
	| tag | minorversion | numops |SEQUENCE op | op + args | ...		| tag | minorversion | numops |SEQUENCE op | op + args | ...
	| | (== 1) | (limited) | + args | |		| | (== 1) | (limited) | + args | |
	+-----+--------------+-----------+------------+-----------+----		+-----+--------------+-----------+------------+-----------+----
	</artwork>		]]></artwork>
	</figure>		<t>
	<t>
	and the replies have the form:		and the replies have the form:
	</t>		</t>
			<artwork name="" type="" align="left" alt=""><![CDATA[
	<figure>
	<artwork>
	+------------+-----+--------+-------------------------------+--//		+------------+-----+--------+-------------------------------+--//
	|last status | tag | numres |status + SEQUENCE op + results | //		|last status | tag | numres |status + SEQUENCE op + results | //
	+------------+-----+--------+-------------------------------+--//		+------------+-----+--------+-------------------------------+--//
	//-----------------------+----		//-----------------------+----
	// status + op + results | ...		// status + op + results | ...
	//-----------------------+----		//-----------------------+----
	</artwork>		]]></artwork>
	</figure>		<t>
	<t>
	A CB_COMPOUND procedure request and reply has a similar form to		A CB_COMPOUND procedure request and reply has a similar form to
	COMPOUND, but		COMPOUND, but
	instead of a SEQUENCE operation, there is a CB_SEQUENCE operation.		instead of a SEQUENCE operation, there is a CB_SEQUENCE operation.
	CB_COMPOUND also has an additional field called "callback_ident", which		CB_COMPOUND also has an additional field called "callback_ident", which
	is superfluous in NFSv4.1 and MUST be ignored by		is superfluous in NFSv4.1 and <bcp14>MUST</bcp14> be ignored by
	the client. CB_SEQUENCE has the same information		the client. CB_SEQUENCE has the same information
	as SEQUENCE, and also includes other information needed to resolve		as SEQUENCE, and also includes other information needed to resolve
	callback races		callback races
	(<xref target="sessions_callback_races" />).		(<xref target="sessions_callback_races" format="default"/>).
	</t>		</t>
	</section> <!-- SEQUENCE and CB_SEQUENCE -->		</section>
	<section anchor="Client_ID_and_Session_Association"		<section anchor="Client_ID_and_Session_Association" numbered="true" toc="defa
	title="Client ID and Session Association">		ult">
	<t>		<name>Client ID and Session Association</name>
	Each client ID (<xref target="Client_Identifiers" />) can have		<t>
			Each client ID (<xref target="Client_Identifiers" format="default"/>) can ha
			ve
	zero or more active sessions. A client ID and associated		zero or more active sessions. A client ID and associated
	session are required to perform file access in		session are required to perform file access in
	NFSv4.1. Each time a session is used (whether by a client sending		NFSv4.1. Each time a session is used (whether by a client sending
	a request to the server or the client replying to a callback		a request to the server or the client replying to a callback
	request from the server), the state leased to its associated		request from the server), the state leased to its associated
	client ID is automatically renewed.		client ID is automatically renewed.
	</t>		</t>
	<t>		<t>
	State (which can consist of share reservations, locks, delegations,		State (which can consist of share reservations, locks, delegations,
	and layouts (<xref target="intro_locking" />)) is tied to		and layouts (<xref target="intro_locking" format="default"/>)) is tied to
	the client ID. Client state is not tied to any individual session.		the client ID. Client state is not tied to any individual session.
	Successive state changing operations from a given state		Successive state changing operations from a given state
	owner MAY go over different sessions, provided the		owner <bcp14>MAY</bcp14> go over different sessions, provided the
	session is associated with the same client ID. A callback		session is associated with the same client ID. A callback
	MAY arrive over a different session than that of the request		<bcp14>MAY</bcp14> arrive over a different session than that of the request
	that originally acquired the state pertaining to the		that originally acquired the state pertaining to the
	callback. For example, if session A is used to		callback. For example, if session A is used to
	acquire a delegation, a request to recall the		acquire a delegation, a request to recall the
	delegation MAY arrive over session B if both sessions are		delegation <bcp14>MAY</bcp14> arrive over session B if both sessions are
	associated with the same client ID. Sections		associated with the same client ID. Sections
	<xref target="Session_Callback_Security" format="counter"/> and		<xref target="Session_Callback_Security" format="counter"/> and
	<xref target="Backchannel_RPC_Security" format="counter"/> discuss		<xref target="Backchannel_RPC_Security" format="counter"/> discuss
	the security considerations around callbacks.		the security considerations around callbacks.
	</t>		</t>
			</section>
	</section> <!-- Client ID and Session Association -->		</section>
	</section> <!-- NFSv4 Integration -->
	<section anchor="Channels" title="Channels">		<section anchor="Channels" numbered="true" toc="default">
	<t>		<name>Channels</name>
			<t>
	A channel is not a connection. A channel represents the		A channel is not a connection. A channel represents the
	direction ONC RPC requests are sent.		direction ONC RPC requests are sent.
	</t>		</t>
	<t>		<t>
	Each session has one or two channels: the fore channel and the backchannel.		Each session has one or two channels: the fore channel and the backchannel.
	Because there are at most two channels per session, and because each		Because there are at most two channels per session, and because each
	channel has a distinct purpose, channels are not assigned		channel has a distinct purpose, channels are not assigned
	identifiers.		identifiers.
	</t>		</t>
	<t>		<t>
	The fore channel is		The fore channel is
	used for ordinary requests from the client to the server, and		used for ordinary requests from the client to the server, and
	carries COMPOUND requests and responses.		carries COMPOUND requests and responses.
	A session always has a fore channel.		A session always has a fore channel.
	</t>		</t>
	<t>		<t>
	The backchannel is used for callback requests from server		The backchannel is used for callback requests from server
	to client, and carries CB_COMPOUND requests and responses.		to client, and carries CB_COMPOUND requests and responses.
	Whether or not there is a backchannel is decided by the		Whether or not there is a backchannel is decided by the
	client; however, many features of NFSv4.1 require a backchannel.		client; however, many features of NFSv4.1 require a backchannel.
	NFSv4.1 servers MUST support backchannels.		NFSv4.1 servers <bcp14>MUST</bcp14> support backchannels.
	</t>		</t>
	<t>		<t>
	Each session has resources for each channel,		Each session has resources for each channel,
	including separate reply caches (see		including separate reply caches (see
	<xref target="Slot_Identifiers_and_Server_Reply_Cache" />).		<xref target="Slot_Identifiers_and_Server_Reply_Cache" format="default"/>).
	Note that even the backchannel requires a reply cache (or, at least,		Note that even the backchannel requires a reply cache (or, at least,
	a slot table in order to detect retries) because		a slot table in order to detect retries) because
	some callback operations are nonidempotent.		some callback operations are non-idempotent.
	</t>		</t>
			<section anchor="conn_chann_assoc" numbered="true" toc="default">
	<section anchor="conn_chann_assoc" title="Association of Connections, Channel		<name>Association of Connections, Channels, and Sessions</name>
	s, and Sessions">		<t>
	<t>
	Each channel is associated with zero or more transport		Each channel is associated with zero or more transport
	connections (whether of the same transport protocol or different		connections (whether of the same transport protocol or different
	transport protocols). A connection can be associated with		transport protocols). A connection can be associated with
	one channel or both channels of a session; the client		one channel or both channels of a session; the client
	and server negotiate whether a connection will carry		and server negotiate whether a connection will carry
	traffic for one channel or both channels via the		traffic for one channel or both channels via the
	CREATE_SESSION (<xref target="OP_CREATE_SESSION"		CREATE_SESSION (<xref target="OP_CREATE_SESSION" format="default"/>) and the
	/>) and the BIND_CONN_TO_SESSION (<xref		BIND_CONN_TO_SESSION (<xref target="OP_BIND_CONN_TO_SESSION" format="default"/>
	target="OP_BIND_CONN_TO_SESSION" />) operations. When a		) operations. When a
	session is created via CREATE_SESSION, the connection		session is created via CREATE_SESSION, the connection
	that transported the CREATE_SESSION request is		that transported the CREATE_SESSION request is
	automatically associated with the fore channel, and		automatically associated with the fore channel, and
	optionally the backchannel. If the client specifies no		optionally the backchannel. If the client specifies no
	state protection (<xref target="OP_EXCHANGE_ID" />)		state protection (<xref target="OP_EXCHANGE_ID" format="default"/>)
	when the session is created, then when SEQUENCE is		when the session is created, then when SEQUENCE is
	transmitted on a different connection, the connection		transmitted on a different connection, the connection
	is automatically associated with the fore channel of		is automatically associated with the fore channel of
	the session specified in the SEQUENCE operation.		the session specified in the SEQUENCE operation.
	</t>		</t>
	<t>		<t>
	A connection's association with a session is		A connection's association with a session is
	not exclusive. A connection associated with the channel(s)		not exclusive. A connection associated with the channel(s)
	of one session may be simultaneously		of one session may be simultaneously
	associated with the channel(s) of other sessions including		associated with the channel(s) of other sessions including
	sessions associated with other client IDs.		sessions associated with other client IDs.
	</t>		</t>
	<t>		<t>
	It is permissible for connections of multiple transport		It is permissible for connections of multiple transport
	types to be associated with the same channel. For		types to be associated with the same channel. For
	example, both TCP and RDMA connections can be		example, both TCP and RDMA connections can be
	associated with the fore channel. In the event an		associated with the fore channel. In the event an
	RDMA and non-RDMA connection are associated with the		RDMA and non-RDMA connection are associated with the
	same channel, the maximum number of slots SHOULD be		same channel, the maximum number of slots <bcp14>SHOULD</bcp14> be
	at least one more than the total number of RDMA credits		at least one more than the total number of RDMA credits
	(<xref target="Slot_Identifiers_and_Server_Reply_Cache" />).		(<xref target="Slot_Identifiers_and_Server_Reply_Cache" format="default"/>).
	This way, if all RDMA credits are used, the non-RDMA		This way, if all RDMA credits are used, the non-RDMA
	connection can have at least one outstanding request.		connection can have at least one outstanding request.
	If a server supports multiple transport types, it MUST		If a server supports multiple transport types, it <bcp14>MUST</bcp14>
	allow a client to associate connections from each transport		allow a client to associate connections from each transport
	to a channel.		to a channel.
	</t>		</t>
	<t>		<t>
	It is permissible for a connection of one type of		It is permissible for a connection of one type of
	transport to be associated with the fore channel,		transport to be associated with the fore channel,
	and a connection of a different type to be associated		and a connection of a different type to be associated
	with the backchannel.		with the backchannel.
	</t>		</t>
	</section>		</section>
	</section> <!-- Channels -->		</section>
	<section title="Server Scope"		<section anchor="Server_Scope" numbered="true" toc="default">
	anchor="Server_Scope">		<name>Server Scope</name>
	<t>		<t>
	Servers each specify a server scope value in the form		Servers each specify a server scope value in the form
	of an opaque string eir_server_scope returned as part of		of an opaque string eir_server_scope returned as part of
	the results of an EXCHANGE_ID operation. The purpose of		the results of an EXCHANGE_ID operation. The purpose of
	the server scope is to allow a group of servers to		the server scope is to allow a group of servers to
	indicate to clients that a set of servers sharing the		indicate to clients that a set of servers sharing the
	same server scope value has arranged to use distinct		same server scope value has arranged to use distinct
	values of opaque identifiers so that the two servers never		values of opaque identifiers so that the two servers never
	assign the same value to two distinct objects. Thus, the identifiers		assign the same value to two distinct objects. Thus, the identifiers
	generated by two servers within that set can be assumed compatible		generated by two servers within that set can be assumed compatible
	so that, in certain important cases,		so that, in certain important cases,
	identifiers generated by one server in that set may be		identifiers generated by one server in that set may be
	presented to		presented to
	another server of the same scope.		another server of the same scope.
	</t>		</t>
	<t>		<t>
	The use of such compatible values does not imply that		The use of such compatible values does not imply that
	a value generated by one server will always be accepted		a value generated by one server will always be accepted
	by another. In most cases, it will not. However, a		by another. In most cases, it will not. However, a
	server will not inadvertently accept a value generated by another		server will not inadvertently accept a value generated by another
	server. When it does accept it, it will be because		server. When it does accept it, it will be because
	it is recognized as valid and carrying the same meaning		it is recognized as valid and carrying the same meaning
	as on another server of the same scope.		as on another server of the same scope.
	</t>		</t>
	<t>		<t>
	When servers are of the same server scope, this compatibility		When servers are of the same server scope, this compatibility
	of values applies to the following identifiers:		of values applies to the following identifiers:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Filehandle values. A filehandle value accepted by two		Filehandle values. A filehandle value accepted by two
	servers of the same server scope denotes the same object.		servers of the same server scope denotes the same object.
	A WRITE operation sent to one server is reflected immediately		A WRITE operation sent to one server is reflected immediately
	in a READ sent to the other.		in a READ sent to the other.
	</t>		</li>
	<t>		<li>
	Server owner values. When the server scope values are		Server owner values. When the server scope values are
	the same, server owner value may be validly compared.		the same, server owner value may be validly compared.
	In cases where the server scope values are different, server		In cases where the server scope values are different, server
	owner values are treated as different even if they		owner values are treated as different even if they
	contain identical strings of bytes.		contain identical strings of bytes.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The coordination among servers required to provide such		The coordination among servers required to provide such
	compatibility can be quite minimal, and limited to a simple		compatibility can be quite minimal, and limited to a simple
	partition of the ID space. The recognition of common values		partition of the ID space. The recognition of common values
	requires additional implementation, but this can be tailored		requires additional implementation, but this can be tailored
	to the specific situations in which that recognition is		to the specific situations in which that recognition is
	desired.		desired.
	</t>		</t>
	<t>		<t>
	Clients will have occasion to compare the server scope values		Clients will have occasion to compare the server scope values
	of multiple servers under a number of circumstances, each of		of multiple servers under a number of circumstances, each of
	which will be discussed under the appropriate functional		which will be discussed under the appropriate functional
	section:		section:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	When server owner values received in response to		When server owner values received in response to
	EXCHANGE_ID operations sent to multiple network		EXCHANGE_ID operations sent to multiple network
	addresses are compared for the purpose of determining		addresses are compared for the purpose of determining
	the validity of various forms of trunking, as described		the validity of various forms of trunking, as described
	in <xref target="SEC11-USES-trunk" />. .		in <xref target="SEC11-USES-trunk" format="default"/>.
	</t>		</li>
	<t>		<li>
	When network or server reconfiguration causes the same		When network or server reconfiguration causes the same
	network address to possibly be directed to different		network address to possibly be directed to different
	servers, with the necessity for the client to determine		servers, with the necessity for the client to determine
	when lock reclaim should be attempted, as described		when lock reclaim should be attempted, as described
	in <xref target="reclaim_locks" />.		in <xref target="reclaim_locks" format="default"/>.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	When two replies from EXCHANGE_ID, each from two different		When two replies from EXCHANGE_ID, each from two different
	server network addresses, have the same server scope, there		server network addresses, have the same server scope, there
	are a number of ways a client can validate that the common		are a number of ways a client can validate that the common
	server scope is due to two servers cooperating in a group.		server scope is due to two servers cooperating in a group.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	If both EXCHANGE_ID requests were sent with RPCSEC_GSS		If both EXCHANGE_ID requests were sent with RPCSEC_GSS
	(<xref target="RFC2203"/>, <xref target="RFC5403"/>,		(<xref target="RFC2203" format="default"/>, <xref target="RFC5403" format
	<xref target="RFC7861"/>)		="default"/>,
			<xref target="RFC7861" format="default"/>)
	authentication and the server principal is the same for		authentication and the server principal is the same for
	both targets, the equality of server scope is validated.		both targets, the equality of server scope is validated.
	It is RECOMMENDED that two servers intending to share the		It is <bcp14>RECOMMENDED</bcp14> that two servers intending to share the
	same server scope and server_owner major_id also share the		same server scope and server_owner major_id also share the
	same principal name. In some cases, this		same principal name. In some cases, this
	simplifies the client's task of validating server scope.		simplifies the client's task of validating server scope.
	</t>		</li>
	<t>		<li>
	The client may accept the appearance of the second		The client may accept the appearance of the second
	server in the fs_locations or fs_locations_info attribute		server in the fs_locations or fs_locations_info attribute
	for a relevant file system. For example, if there is		for a relevant file system. For example, if there is
	a migration event for a particular file system		a migration event for a particular file system
	or there are locks to be reclaimed on a particular file		or there are locks to be reclaimed on a particular file
	system, the attributes for that particular file system		system, the attributes for that particular file system
	may be used. The client sends the GETATTR request to		may be used. The client sends the GETATTR request to
	the first server for the fs_locations or		the first server for the fs_locations or
	fs_locations_info attribute with RPCSEC_GSS		fs_locations_info attribute with RPCSEC_GSS
	authentication. It may need to do this in advance		authentication. It may need to do this in advance
	of the need to verify the common server scope.		of the need to verify the common server scope.
	If the client successfully authenticates the reply		If the client successfully authenticates the reply
	to GETATTR, and the GETATTR request and reply containing		to GETATTR, and the GETATTR request and reply containing
	the fs_locations or fs_locations_info attribute refers		the fs_locations or fs_locations_info attribute refers
	to the second server, then the equality of server scope		to the second server, then the equality of server scope
	is supported. A client may choose to limit the use of		is supported. A client may choose to limit the use of
	this form of support to information relevant to the		this form of support to information relevant to the
	specific file system involved (e.g. a file system		specific file system involved (e.g. a file system
	being migrated).		being migrated).
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section anchor="Trunking" numbered="true" toc="default">
	<section title="Trunking"		<name>Trunking</name>
	anchor="Trunking">		<t>
	<t>
	Trunking is the use of multiple connections between a		Trunking is the use of multiple connections between a
	client and server in order to increase the speed of data		client and server in order to increase the speed of data
	transfer. NFSv4.1 supports two types of trunking:		transfer. NFSv4.1 supports two types of trunking:
	session trunking and client ID trunking.		session trunking and client ID trunking.
	</t>		</t>
	<t>		<t>
	In the context of a single server network address, it		In the context of a single server network address, it
	can be assumed that all connections are accessing the		can be assumed that all connections are accessing the
	same server and NFSv4.1		same server, and NFSv4.1
	servers MUST support both forms of trunking. When		servers <bcp14>MUST</bcp14> support both forms of trunking. When
	multiple connections use a set of network addresses		multiple connections use a set of network addresses
	accessing the same server, the server		to access the same server, the server
	MUST support both forms of trunking.		<bcp14>MUST</bcp14> support both forms of trunking.
	NFSv4.1 servers in a clustered configuration MAY allow		NFSv4.1 servers in a clustered configuration <bcp14>MAY</bcp14> allow
	network addresses for different servers to use client ID		network addresses for different servers to use client ID
	trunking.		trunking.
	</t>		</t>
	<t>		<t>
	Clients may use either form of trunking as long as they		Clients may use either form of trunking as long as they
	do not, when trunking between different server network		do not, when trunking between different server network
	addresses, violate the servers' mandates as to the		addresses, violate the servers' mandates as to the
	kinds of trunking to be allowed (see below). With regard		kinds of trunking to be allowed (see below). With regard
	to callback channels, the client MUST allow the server to		to callback channels, the client <bcp14>MUST</bcp14> allow the server to
	choose among all callback channels valid for a given		choose among all callback channels valid for a given
	client ID and MUST support trunking when the connections		client ID and <bcp14>MUST</bcp14> support trunking when the connections
	supporting the backchannel allow session or client ID		supporting the backchannel allow session or client ID
	trunking to be used for callbacks.		trunking to be used for callbacks.
	</t>		</t>
	<t>		<t>
	Session trunking is essentially the association of multiple		Session trunking is essentially the association of multiple
	connections, each with potentially different target and/or source		connections, each with potentially different target and/or source
	network addresses, to the same session. When the target network		network addresses, to the same session. When the target network
	addresses (server addresses) of the two connections are the same,		addresses (server addresses) of the two connections are the same,
	the server MUST		the server <bcp14>MUST</bcp14>
	support such session trunking. When the target network addresses		support such session trunking. When the target network addresses
	are different, the server MAY indicate such support using the		are different, the server <bcp14>MAY</bcp14> indicate such support using th e
	data returned by the EXCHANGE_ID operation (see below).		data returned by the EXCHANGE_ID operation (see below).
	</t>		</t>
	<t>		<t>
	Client ID trunking is the association of multiple		Client ID trunking is the association of multiple
	sessions to the same client ID. Servers MUST support client ID		sessions to the same client ID. Servers <bcp14>MUST</bcp14> support client ID
	trunking for two target network addresses whenever they allow		trunking for two target network addresses whenever they allow
	session trunking for those same two network addresses.		session trunking for those same two network addresses.
	In addition, a server MAY, by presenting the same		In addition, a server <bcp14>MAY</bcp14>, by presenting the same
	major server owner ID		major server owner ID
	(<xref target="Server_Owners" />) and server scope		(<xref target="Server_Owners" format="default"/>) and server scope
	(<xref target="Server_Scope" />), allow an additional		(<xref target="Server_Scope" format="default"/>), allow an additional
	case of client ID trunking. When two		case of client ID trunking. When two
	servers return the same major server owner and server		servers return the same major server owner and server
	scope, it means that the two servers are cooperating on		scope, it means that the two servers are cooperating on
	locking state management, which is a prerequisite		locking state management, which is a prerequisite
	for client ID trunking.		for client ID trunking.
	</t>		</t>
	<t>		<t>
	Distinguishing when the client is allowed to use session and		Distinguishing when the client is allowed to use session and
	client ID trunking requires understanding how the results of the		client ID trunking requires understanding how the results of the
	EXCHANGE_ID (<xref target="OP_EXCHANGE_ID" />)		EXCHANGE_ID (<xref target="OP_EXCHANGE_ID" format="default"/>)
	operation identify a server.		operation identify a server.
	Suppose a client sends EXCHANGE_IDs over two different		Suppose a client sends EXCHANGE_IDs over two different
	connections, each with a possibly different target		connections, each with a possibly different target
	network address, but each EXCHANGE_ID operation has the same		network address, but each EXCHANGE_ID operation has the same
	value in the eia_clientowner field. If the same		value in the eia_clientowner field. If the same
	NFSv4.1 server is listening over each connection,		NFSv4.1 server is listening over each connection,
	then each EXCHANGE_ID result MUST return the same		then each EXCHANGE_ID result <bcp14>MUST</bcp14> return the same
	values of eir_clientid, eir_server_owner.so_major_id,		values of eir_clientid, eir_server_owner.so_major_id,
	and eir_server_scope. The client can then treat each		and eir_server_scope. The client can then treat each
	connection as referring to the same server (subject		connection as referring to the same server (subject
	to verification; see		to verification; see
	<xref target="PREP-trunk-verify" /> below),		<xref target="PREP-trunk-verify" format="default"/> below),
	and it can use each connection to trunk requests and		and it can use each connection to trunk requests and
	replies.		replies.
	The client's choice is whether session trunking		The client's choice is whether session trunking
	or client ID trunking applies.		or client ID trunking applies.
	<list style="hanging">		</t>
			<dl newline="false" spacing="normal">
	<t hangText="Session Trunking.">		<dt>Session Trunking.</dt>
			<dd>
			<t>
	If the eia_clientowner argument is the same in		If the eia_clientowner argument is the same in
	two different EXCHANGE_ID requests, and		two different EXCHANGE_ID requests, and
	the eir_clientid, eir_server_owner.so_major_id,		the eir_clientid, eir_server_owner.so_major_id,
	eir_server_owner.so_minor_id, and eir_server_scope		eir_server_owner.so_minor_id, and eir_server_scope
	results match in both EXCHANGE_ID results, then		results match in both EXCHANGE_ID results, then
	the client is permitted to perform session trunking.		the client is permitted to perform session trunking.
	If the client has no session mapping to the tuple of		If the client has no session mapping to the tuple of
	eir_clientid, eir_server_owner.so_major_id, eir_server_scope, and		eir_clientid, eir_server_owner.so_major_id, eir_server_scope, and
	eir_server_owner.so_minor_id, then it creates		eir_server_owner.so_minor_id, then it creates
	the session via a CREATE_SESSION operation over one		the session via a CREATE_SESSION operation over one
	of the connections, which associates the connection		of the connections, which associates the connection
	to the session. If there is a session for the tuple,		to the session. If there is a session for the tuple,
	the client can send BIND_CONN_TO_SESSION to associate		the client can send BIND_CONN_TO_SESSION to associate
	the connection to the session.		the connection to the session.
	<vspace blankLines='1' />		</t>
			<t>
	Of course, if the client		Of course, if the client
	does not desire to use session trunking, it is not		does not desire to use session trunking, it is not
	required to do so. It can invoke		required to do so. It can invoke
	CREATE_SESSION on the connection. This will result		CREATE_SESSION on the connection. This will result
	in client ID trunking as described below. It can also		in client ID trunking as described below. It can also
	decide to drop the connection if it does not choose to		decide to drop the connection if it does not choose to
	use trunking.		use trunking.
	<vspace blankLines='1' />		</t>
			</dd>
	</t>		<dt>Client ID Trunking.</dt>
			<dd>
	<t hangText="Client ID Trunking.">		<t>
	If the eia_clientowner argument is the same in		If the eia_clientowner argument is the same in
	two different EXCHANGE_ID requests, and		two different EXCHANGE_ID requests, and
	the eir_clientid, eir_server_owner.so_major_id,		the eir_clientid, eir_server_owner.so_major_id,
	and eir_server_scope		and eir_server_scope
	results match in both EXCHANGE_ID results, then		results match in both EXCHANGE_ID results, then
	the client is permitted to perform client ID trunking		the client is permitted to perform client ID trunking
	(regardless of whether the eir_server_owner.so_minor_id results match).		(regardless of whether the eir_server_owner.so_minor_id results match).
	The client can associate		The client can associate
	each connection with different sessions, where		each connection with different sessions, where
	each session is associated with the same server.		each session is associated with the same server.
			</t>
	<vspace blankLines='1' />		<t>
	The client completes the act of client ID trunking by invoking		The client completes the act of client ID trunking by invoking
	CREATE_SESSION on each connection, using the same		CREATE_SESSION on each connection, using the same
	client ID that was returned in eir_clientid. These		client ID that was returned in eir_clientid. These
	invocations create two sessions and also associate		invocations create two sessions and also associate
	each connection with its respective session. The client		each connection with its respective session. The client
	is free to decline to use client ID trunking by simply		is free to decline to use client ID trunking by simply
	dropping the connection at this point.		dropping the connection at this point.
			</t>
	<vspace blankLines='1' />		<t>
	When doing client ID trunking, locking state		When doing client ID trunking, locking state
	is shared across sessions associated with that same		is shared across sessions associated with that same
	client ID. This requires the server to coordinate		client ID. This requires the server to coordinate
	state across sessions and the client to be able to		state across sessions and the client to be able to
	associate the same locking state with multiple sessions.		associate the same locking state with multiple sessions.
			</t>
	</t>		</dd>
			</dl>
	</list>		<t>
	</t>
	<t>
	It is always possible that, as a result of various sorts		It is always possible that, as a result of various sorts
	of reconfiguration events, eir_server_scope and		of reconfiguration events, eir_server_scope and
	eir_server_owner values may be different on subsequent		eir_server_owner values may be different on subsequent
	EXCHANGE_ID requests made to the same network address.		EXCHANGE_ID requests made to the same network address.
	</t>		</t>
	<t>		<t>
	In most cases such reconfiguration events will be		In most cases, such reconfiguration events will be
	disruptive and indicate that an IP address formerly connected		disruptive and indicate that an IP address formerly connected
	to one server is now connected to an entirely different one.		to one server is now connected to an entirely different one.
	</t>		</t>
	<t>		<t>
	Some guidelines on client handling of such situations follow:		Some guidelines on client handling of such situations follow:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	When eir_server_scope changes, the client has no assurance		When eir_server_scope changes, the client has no assurance
	that any id's it obtained previously (e.g. file handles) can		that any IDs that it obtained previously (e.g., filehandles) can
	be validly used on the new server, and, even if the new		be validly used on the new server, and, even if the new
	server accepts them, there is no assurance that this is not		server accepts them, there is no assurance that this is not
	due to accident. Thus, it is best to treat all such state		due to accident. Thus, it is best to treat all such state
	as lost/stale although a client may assume that the		as lost or stale, although a client may assume that the
	probability of inadvertent acceptance is low and treat		probability of inadvertent acceptance is low and treat
	this situation as within the next case.		this situation as within the next case.
	</t>		</li>
	<t>		<li>
	When eir_server_scope remains the same and		When eir_server_scope remains the same and
	eir_server_owner.so_major_id changes, the client can use		eir_server_owner.so_major_id changes, the client can use
	the filehandles it has, consider its locking state lost,		the filehandles it has, consider its locking state lost,
	and attempt		and attempt
	to reclaim or otherwise re-obtain its locks. It might find		to reclaim or otherwise re-obtain its locks. It might find
	that		that
	its file handle is now stale. However, if NFS4ERR_STALE is not		its filehandle is now stale. However, if NFS4ERR_STALE is not
	returned, it can proceed to reclaim or otherwise re-obtain its		returned, it can proceed to reclaim or otherwise re-obtain its
	open locking state.		open locking state.
	</t>		</li>
	<t>		<li>
	When eir_server_scope and		When eir_server_scope and
	eir_server_owner.so_major_id remain the same,		eir_server_owner.so_major_id remain the same,
	the client has to use the now-current values		the client has to use the now-current values
	of eir_server_owner.so_minor_id in deciding on appropriate		of eir_server_owner.so_minor_id in deciding on appropriate
	forms of trunking. This may result in connections being		forms of trunking. This may result in connections being
	dropped or new sessions being created.		dropped or new sessions being created.
	</t>		</li>
	</list>		</ul>
	</t>		<section anchor="PREP-trunk-verify" numbered="true" toc="default">
	<section title="Verifying Claims of Matching Server Identity"		<name>Verifying Claims of Matching Server Identity</name>
	anchor="PREP-trunk-verify">		<t>
	<t>		When the server responds using two different connections that claim
	When the server responds using two different connections claiming
	matching or partially matching eir_server_owner,		matching or partially matching eir_server_owner,
	eir_server_scope, and eir_clientid values, the client		eir_server_scope, and eir_clientid values, the client
	does not have to trust the servers' claims. The client		does not have to trust the servers' claims. The client
	may verify these claims before trunking traffic in		may verify these claims before trunking traffic in
	the following ways:		the following ways:
	<list style='symbols'>		</t>
			<ul spacing="normal">
	<t>		<li>
			<t>
	For session trunking,		For session trunking,
	clients SHOULD		clients <bcp14>SHOULD</bcp14>
	reliably verify if connections between different		reliably verify if connections between different
	network paths are in fact associated with the same NFSv4.1		network paths are in fact associated with the same NFSv4.1
	server and usable on the same session, and servers		server and usable on the same session, and servers
	MUST allow clients to perform reliable verification.		<bcp14>MUST</bcp14> allow clients to perform reliable verification.
	When a client ID is created, the client SHOULD specify that		When a client ID is created, the client <bcp14>SHOULD</bcp14> specify that
	BIND_CONN_TO_SESSION is to be verified according to the		BIND_CONN_TO_SESSION is to be verified according to the
	SP4_SSV or SP4_MACH_CRED (<xref target="OP_EXCHANGE_ID" />)		SP4_SSV or SP4_MACH_CRED (<xref target="OP_EXCHANGE_ID" format="default"/> )
	state protection options. For SP4_SSV, reliable		state protection options. For SP4_SSV, reliable
	verification depends on a shared secret (the		verification depends on a shared secret (the
	SSV) that is established via the SET_SSV (see		SSV) that is established via the SET_SSV (see
	<xref target="OP_SET_SSV" />) operation.		<xref target="OP_SET_SSV" format="default"/>) operation.
	<vspace blankLines='1' />		</t>
			<t>
	When a new connection is associated with the		When a new connection is associated with the
	session (via the BIND_CONN_TO_SESSION operation,		session (via the BIND_CONN_TO_SESSION operation,
	see <xref target="OP_BIND_CONN_TO_SESSION" />), if		see <xref target="OP_BIND_CONN_TO_SESSION" format="default"/>), if
	the client specified SP4_SSV state protection for the		the client specified SP4_SSV state protection for the
	BIND_CONN_TO_SESSION operation, the client MUST send		BIND_CONN_TO_SESSION operation, the client <bcp14>MUST</bcp14> send
	the BIND_CONN_TO_SESSION with RPCSEC_GSS protection,		the BIND_CONN_TO_SESSION with RPCSEC_GSS protection,
	using integrity or privacy, and an RPCSEC_GSS handle created		using integrity or privacy, and an RPCSEC_GSS handle created
	with the GSS SSV mechanism (see <xref		with the GSS SSV mechanism (see <xref target="ssv_mech" format="default"/>
	target="ssv_mech" />).		).
	<vspace blankLines='1' />		</t>
			<t>
	If the client mistakenly tries to associate a		If the client mistakenly tries to associate a
	connection to a session of a wrong server, the		connection to a session of a wrong server, the
	server will either reject the attempt because		server will either reject the attempt because
	it is not aware of the session identifier of the		it is not aware of the session identifier of the
	BIND_CONN_TO_SESSION arguments, or it will reject		BIND_CONN_TO_SESSION arguments, or it will reject
	the attempt because the RPCSEC_GSS authentication		the attempt because the RPCSEC_GSS authentication
	fails. Even if the server mistakenly or maliciously		fails. Even if the server mistakenly or maliciously
	accepts the connection association attempt, the		accepts the connection association attempt, the
	RPCSEC_GSS verifier it computes in the response		RPCSEC_GSS verifier it computes in the response
	will not be verified by the client, so the client will		will not be verified by the client, so the client will
	know it cannot use the connection for trunking the		know it cannot use the connection for trunking the
	specified session. <vspace blankLines='1' /> If the		specified session. </t>
			<t> If the
	client specified SP4_MACH_CRED state protection, the		client specified SP4_MACH_CRED state protection, the
	BIND_CONN_TO_SESSION operation will use RPCSEC_GSS		BIND_CONN_TO_SESSION operation will use RPCSEC_GSS
	integrity or privacy, using the same credential that		integrity or privacy, using the same credential that
	was used when the client ID was created. Mutual		was used when the client ID was created. Mutual
	authentication via RPCSEC_GSS assures the client		authentication via RPCSEC_GSS assures the client
	that the connection is associated with the correct		that the connection is associated with the correct
	session of the correct server.		session of the correct server.
	<vspace blankLines='1' />		</t>
	</t>		</li>
	<t>		<li>
			<t>
	For client ID trunking, the client has at least two		For client ID trunking, the client has at least two
	options for verifying that the same client ID		options for verifying that the same client ID
	obtained from two different EXCHANGE_ID operations		obtained from two different EXCHANGE_ID operations
	came from the same server. The first option is		came from the same server. The first option is
	to use RPCSEC_GSS authentication when sending each		to use RPCSEC_GSS authentication when sending each
	EXCHANGE_ID operation. Each time an EXCHANGE_ID is sent with		EXCHANGE_ID operation. Each time an EXCHANGE_ID is sent with
	RPCSEC_GSS authentication, the client notes the		RPCSEC_GSS authentication, the client notes the
	principal name of the GSS target. If the EXCHANGE_ID		principal name of the GSS target. If the EXCHANGE_ID
	results indicate that client ID trunking is possible,		results indicate that client ID trunking is possible,
	and the GSS targets' principal names are the same,		and the GSS targets' principal names are the same,
	the servers are the same and client ID trunking is		the servers are the same and client ID trunking is
	allowed.		allowed.
	<vspace blankLines='1' />		</t>
			<t>
	The second option for verification is to		The second option for verification is to
	use SP4_SSV protection. When the client sends		use SP4_SSV protection. When the client sends
	EXCHANGE_ID, it specifies SP4_SSV protection. The		EXCHANGE_ID, it specifies SP4_SSV protection. The
	first EXCHANGE_ID the client sends always has to		first EXCHANGE_ID the client sends always has to
	be confirmed by a CREATE_SESSION call. The client		be confirmed by a CREATE_SESSION call. The client
	then sends SET_SSV. Later, the client		then sends SET_SSV. Later, the client
	sends EXCHANGE_ID to a second destination		sends EXCHANGE_ID to a second destination
	network address different from the one the first		network address different from the one the first
	EXCHANGE_ID was sent to.		EXCHANGE_ID was sent to.
	skipping to change at line 3039 ¶		skipping to change at line 3020 ¶
	claim by sending a CREATE_SESSION operation to the second		claim by sending a CREATE_SESSION operation to the second
	destination address, protected with RPCSEC_GSS integrity		destination address, protected with RPCSEC_GSS integrity
	using an RPCSEC_GSS handle returned by the second		using an RPCSEC_GSS handle returned by the second
	EXCHANGE_ID. If the server accepts the CREATE_SESSION		EXCHANGE_ID. If the server accepts the CREATE_SESSION
	request, and if the client verifies the RPCSEC_GSS		request, and if the client verifies the RPCSEC_GSS
	verifier and integrity codes, then the client has		verifier and integrity codes, then the client has
	proof the second server knows the SSV, and thus		proof the second server knows the SSV, and thus
	the two servers are cooperating for the purposes of		the two servers are cooperating for the purposes of
	specifying server scope and client ID trunking.		specifying server scope and client ID trunking.
	</t>		</t>
	</list>		</li>
	</t>		</ul>
			</section>
	</section>		</section>
	</section>		<section anchor="Exactly_Once_Semantics" numbered="true" toc="default">
			<name>Exactly Once Semantics</name>
	<section anchor="Exactly_Once_Semantics" title="Exactly Once Semantics">		<t>
	<t>
	Via the session, NFSv4.1 offers exactly once semantics (EOS)		Via the session, NFSv4.1 offers exactly once semantics (EOS)
	for requests sent over a channel. EOS is supported on both the		for requests sent over a channel. EOS is supported on both the
	fore channel and backchannel.		fore channel and backchannel.
	</t>		</t>
	<t>		<t>
	Each COMPOUND or CB_COMPOUND request that is sent		Each COMPOUND or CB_COMPOUND request that is sent
	with a leading SEQUENCE or CB_SEQUENCE operation MUST		with a leading SEQUENCE or CB_SEQUENCE operation <bcp14>MUST</bcp14>
	be executed by the receiver exactly once. This requirement		be executed by the receiver exactly once. This requirement
	holds regardless of whether the request is sent with reply		holds regardless of whether the request is sent with reply
	caching specified (see <xref target="optional_reply_caching" />).		caching specified (see <xref target="optional_reply_caching" format="default" />).
	The requirement holds even if the requester is sending the		The requirement holds even if the requester is sending the
	request over a session created between a pNFS data client		request over a session created between a pNFS data client
	and pNFS data server. To understand the rationale for this requirement,		and pNFS data server. To understand the rationale for this requirement,
	divide the requests into three		divide the requests into three
	classifications:		classifications:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	Non-idempotent requests.		Non-idempotent requests.
	</t>		</li>
	<t>		<li>
	Idempotent modifying requests.		Idempotent modifying requests.
	</t>		</li>
	<t>		<li>
	Idempotent non-modifying requests.		Idempotent non-modifying requests.
	</t>		</li>
	</list>		</ul>
			<t>
	An example of a non-idempotent request is		An example of a non-idempotent request is
	RENAME. Obviously, if a replier executes the		RENAME. Obviously, if a replier executes the
	same RENAME request twice, and the first execution succeeds,		same RENAME request twice, and the first execution succeeds,
	the re-execution will fail. If the replier returns the		the re-execution will fail. If the replier returns the
	result from the re-execution, this result is incorrect.		result from the re-execution, this result is incorrect.
	Therefore, EOS is required for non-idempotent requests.		Therefore, EOS is required for non-idempotent requests.
	</t>		</t>
	<t>		<t>
	An example of an idempotent modifying request is		An example of an idempotent modifying request is
	a COMPOUND request containing a WRITE operation.		a COMPOUND request containing a WRITE operation.
	Repeated execution of the same WRITE		Repeated execution of the same WRITE
	has the same effect as execution of that WRITE a single time.		has the same effect as execution of that WRITE a single time.
	Nevertheless, enforcing EOS for WRITEs and other idempotent		Nevertheless, enforcing EOS for WRITEs and other idempotent
	modifying requests is necessary		modifying requests is necessary
	to avoid data corruption.		to avoid data corruption.
	</t>		</t>
	<t>		<t>
	Suppose a client sends WRITE A to a		Suppose a client sends WRITE A to a
	noncompliant server that does not enforce EOS, and		noncompliant server that does not enforce EOS, and
	receives no response, perhaps due to a network		receives no response, perhaps due to a network
	partition. The client reconnects to the server and		partition. The client reconnects to the server and
	re-sends WRITE A. Now, the server has		re-sends WRITE A. Now, the server has
	outstanding two instances of A. The		outstanding two instances of A. The
	server can be in a situation in which it executes and		server can be in a situation in which it executes and
	replies to the retry of A, while the first		replies to the retry of A, while the first
	A is still waiting in the server's internal I/O system for some		A is still waiting in the server's internal I/O system for some
	resource. Upon receiving the		resource. Upon receiving the
	reply to the second attempt of WRITE A,		reply to the second attempt of WRITE A,
	the client believes its WRITE is done so it is free		the client believes its WRITE is done so it is free
	to send WRITE B, which overlaps the byte-range of		to send WRITE B, which overlaps the byte-range of
	A. When the original A is dispatched from the server's		A. When the original A is dispatched from the server's
	I/O system and		I/O system and
	executed (thus the second time A will have		executed (thus the second time A will have
	been written), then what has been		been written), then what has been
	written by B can be overwritten and thus corrupted.		written by B can be overwritten and thus corrupted.
	</t>		</t>
	<t>		<t>
	An example of an idempotent non-modifying request		An example of an idempotent non-modifying request
	is a COMPOUND containing SEQUENCE, PUTFH, READLINK,		is a COMPOUND containing SEQUENCE, PUTFH, READLINK,
	and nothing else. The re-execution of such a		and nothing else. The re-execution of such a
	request will not cause data corruption or		request will not cause data corruption or
	produce an incorrect result. Nonetheless,		produce an incorrect result. Nonetheless,
	to keep the implementation simple,		to keep the implementation simple,
	the replier MUST enforce EOS for all requests, whether or not		the replier <bcp14>MUST</bcp14> enforce EOS for all requests, whether or not
	idempotent and non-modifying.		idempotent and non-modifying.
	</t>		</t>
	<t>		<t>
	Note that true and complete EOS is not possible unless the		Note that true and complete EOS is not possible unless the
	server persists the reply cache in stable storage, and unless the		server persists the reply cache in stable storage, and unless the
	server is somehow implemented to never require a restart		server is somehow implemented to never require a restart
	(indeed, if such a server exists, the distinction between a		(indeed, if such a server exists, the distinction between a
	reply cache kept in stable storage versus one that is not is		reply cache kept in stable storage versus one that is not is
	one without meaning). See <xref target="Persistence" /> for		one without meaning). See <xref target="Persistence" format="default"/> for
	a discussion of persistence in the reply cache.		a discussion of persistence in the reply cache.
	Regardless, even if the server does not persist the reply cache,		Regardless, even if the server does not persist the reply cache,
	EOS improves robustness and correctness over previous versions		EOS improves robustness and correctness over previous versions
	of NFS because the legacy duplicate request/reply caches were		of NFS because the legacy duplicate request/reply caches were
	based on the ONC RPC transaction identifier (XID).		based on the ONC RPC transaction identifier (XID).
	<xref target="Slot_Identifiers_and_Server_Reply_Cache" />		<xref target="Slot_Identifiers_and_Server_Reply_Cache" format="default"/>
	explains the shortcomings of the XID as a basis for		explains the shortcomings of the XID as a basis for
	a reply cache and describes how NFSv4.1 sessions improve		a reply cache and describes how NFSv4.1 sessions improve
	upon the XID.		upon the XID.
	</t>		</t>
			<section anchor="Slot_Identifiers_and_Server_Reply_Cache" numbered="tr
	<section anchor="Slot_Identifiers_and_Server_Reply_Cache"		ue" toc="default">
	title="Slot Identifiers and Reply Cache">		<name>Slot Identifiers and Reply Cache</name>
	<t>		<t>
	The RPC layer provides a transaction ID (XID), which,		The RPC layer provides a transaction ID (XID), which,
	while required to be unique, is not		while required to be unique, is not
	convenient for tracking requests for two reasons.		convenient for tracking requests for two reasons.
	First, the XID is only		First, the XID is only
	meaningful to the requester; it cannot be interpreted		meaningful to the requester; it cannot be interpreted
	by the replier except to test for equality with		by the replier except to test for equality with
	previously sent requests. When consulting an RPC-based		previously sent requests. When consulting an RPC-based
	duplicate request cache, the opaqueness of the XID requires		duplicate request cache, the opaqueness of the XID requires
	a computationally expensive look up (often via a hash that		a computationally expensive look up (often via a hash that
	includes XID and source address). NFSv4.1 requests use		includes XID and source address). NFSv4.1 requests use
	a non-opaque slot ID, which is an index into a slot table,		a non-opaque slot ID, which is an index into a slot table,
	which is far more efficient. Second, because RPC requests		which is far more efficient. Second, because RPC requests
	can be executed by the replier in any order, there is		can be executed by the replier in any order, there is
	no bound on the number of requests that may be outstanding		no bound on the number of requests that may be outstanding
	at any time. To achieve perfect EOS, using ONC RPC		at any time. To achieve perfect EOS, using ONC RPC
	would require storing all replies in the reply cache.		would require storing all replies in the reply cache.
	XIDs are 32 bits; storing over four billion (2^32) replies		XIDs are 32 bits; storing over four billion (2<sup>32</sup>) replies
	in the reply cache is not practical. In practice, previous versions		in the reply cache is not practical. In practice, previous versions
	of NFS have chosen to store a fixed number of replies in		of NFS have chosen to store a fixed number of replies in
	the cache, and to use a least recently used (LRU) approach to		the cache, and to use a least recently used (LRU) approach to
	replacing cache entries with new entries when the cache		replacing cache entries with new entries when the cache
	is full. In NFSv4.1, the number of outstanding requests is		is full. In NFSv4.1, the number of outstanding requests is
	bounded by the size of the slot table, and a sequence ID		bounded by the size of the slot table, and a sequence ID
	per slot is used to tell the replier when it is safe to		per slot is used to tell the replier when it is safe to
	delete a cached reply.		delete a cached reply.
	</t>		</t>
	<t>		<t>
	In the NFSv4.1 reply cache, when the requester sends a new request,		In the NFSv4.1 reply cache, when the requester sends a new request,
	it selects a slot ID in the		it selects a slot ID in the
	range 0..N, where N is the replier's current maximum slot ID		range 0..N, where N is the replier's current maximum slot ID
	granted to the requester on the session over which the request is to be		granted to the requester on the session over which the request is to be
	sent. The value of N starts out as equal to		sent. The value of N starts out as equal to
	ca_maxrequests - 1 (<xref target="OP_CREATE_SESSION" />), but		ca_maxrequests - 1 (<xref target="OP_CREATE_SESSION" format="default"/>), b ut
	can be adjusted by the response to SEQUENCE or CB_SEQUENCE as described		can be adjusted by the response to SEQUENCE or CB_SEQUENCE as described
	later in this section.		later in this section.
	The slot ID must be unused by any of the requests that the		The slot ID must be unused by any of the requests that the
	requester has already active on the session. "Unused" here means the		requester has already active on the session. "Unused" here means the
	requester has no outstanding request for that slot ID.		requester has no outstanding request for that slot ID.
	</t>		</t>
	<t>		<t>
	A slot contains a sequence ID and the cached reply corresponding to		A slot contains a sequence ID and the cached reply corresponding to
	the request sent with that sequence ID. The sequence ID is a		the request sent with that sequence ID. The sequence ID is a
	32-bit unsigned value, and is therefore in the range 0..0xFFFFFFFF (2^32 -		32-bit unsigned value, and is therefore in the range 0..0xFFFFFFFF (2<sup>3
	1).		2</sup> - 1).
	The first time a slot is used, the requester MUST specify		The first time a slot is used, the requester <bcp14>MUST</bcp14> specify
	a sequence ID of one (<xref target="OP_CREATE_SESSION" />).		a sequence ID of one (<xref target="OP_CREATE_SESSION" format="default"/>).
	Each time a slot is reused, the request MUST specify a sequence ID		Each time a slot is reused, the request <bcp14>MUST</bcp14> specify a seque
			nce ID
	that is one greater than that of the previous request on the		that is one greater than that of the previous request on the
	slot. If the previous sequence ID was 0xFFFFFFFF, then the next		slot. If the previous sequence ID was 0xFFFFFFFF, then the next
	request for the slot MUST have the sequence ID set to zero (i.e.,		request for the slot <bcp14>MUST</bcp14> have the sequence ID set to zero (
	(2^32 - 1) + 1 mod 2^32).		i.e.,
	</t>		(2<sup>32</sup> - 1) + 1 mod 2<sup>32</sup>).
	<t>		</t>
			<t>
	The sequence ID accompanies the slot ID in each request. It is		The sequence ID accompanies the slot ID in each request. It is
	for the critical check at the replier: it used to efficiently		for the critical check at the replier: it used to efficiently
	determine whether a request using a certain		determine whether a request using a certain
	slot ID is a retransmit or a new, never-before-seen request. It is		slot ID is a retransmit or a new, never-before-seen request. It is
	not feasible for the requester to assert that it is retransmitting to		not feasible for the requester to assert that it is retransmitting to
	implement this, because for any given request the requester cannot		implement this, because for any given request the requester cannot
	know whether the replier has seen it unless the replier actually replies. Of		know whether the replier has seen it unless the replier actually replies. Of
	course, if the requester has seen the reply, the requester would		course, if the requester has seen the reply, the requester would
	not retransmit.		not retransmit.
	</t>		</t>
	<t>		<t>
	The replier compares each received request's		The replier compares each received request's
	sequence ID with the last one previously received for that slot ID,		sequence ID with the last one previously received for that slot ID,
	to see if the new request is:		to see if the new request is:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style="symbols">		<li>
	<t>
	A new request, in which the sequence ID is one greater		A new request, in which the sequence ID is one greater
	than that previously seen in the slot (accounting for sequence		than that previously seen in the slot (accounting for sequence
	wraparound). The replier proceeds to execute the new request,		wraparound). The replier proceeds to execute the new request,
	and the replier		and the replier
	MUST increase the slot's sequence ID by one.		<bcp14>MUST</bcp14> increase the slot's sequence ID by one.
	</t>		</li>
	<t>		<li>
	A retransmitted request, in which the sequence ID is equal to		A retransmitted request, in which the sequence ID is equal to
	that currently recorded in the slot.		that currently recorded in the slot.
	If the original request has		If the original request has
	executed to completion, the replier returns the cached		executed to completion, the replier returns the cached
	reply. See <xref target="Retry_and_Replay" /> for direction on how the rep lier		reply. See <xref target="Retry_and_Replay" format="default"/> for directio n on how the replier
	deals with retries of requests that are still in progress.		deals with retries of requests that are still in progress.
	</t>		</li>
	<t>		<li>
	A misordered retry, in which the sequence ID		A misordered retry, in which the sequence ID
	is less than (accounting for sequence wraparound)		is less than (accounting for sequence wraparound)
	that previously seen in the slot. The		that previously seen in the slot. The
	replier MUST return NFS4ERR_SEQ_MISORDERED (as the		replier <bcp14>MUST</bcp14> return NFS4ERR_SEQ_MISORDERED (as the
	result from SEQUENCE or CB_SEQUENCE).		result from SEQUENCE or CB_SEQUENCE).
	</t>		</li>
	<t>		<li>
	A misordered new request, in which the sequence ID		A misordered new request, in which the sequence ID
	is two or more than (accounting for sequence		is two or more than (accounting for sequence
	wraparound) that previously seen in the		wraparound) that previously seen in the
	slot. Note that because the sequence ID MUST		slot. Note that because the sequence ID <bcp14>MUST</bcp14>
	wrap around to zero once it reaches 0xFFFFFFFF, a		wrap around to zero once it reaches 0xFFFFFFFF, a
	misordered new request and a misordered retry		misordered new request and a misordered retry
	cannot be distinguished. Thus, the replier MUST		cannot be distinguished. Thus, the replier <bcp14>MUST</bcp14>
	return NFS4ERR_SEQ_MISORDERED (as the result from		return NFS4ERR_SEQ_MISORDERED (as the result from
	SEQUENCE or CB_SEQUENCE).		SEQUENCE or CB_SEQUENCE).
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Unlike the XID, the slot ID is always within a specific		Unlike the XID, the slot ID is always within a specific
	range; this has two implications. The first		range; this has two implications. The first
	implication is that for a given session, the replier		implication is that for a given session, the replier
	need only cache the results of a limited number of		need only cache the results of a limited number of
	COMPOUND requests.		COMPOUND requests.
	The second implication derives		The second implication derives
	from the first, which is that unlike XID-indexed reply		from the first, which is that unlike XID-indexed reply
	caches (also known as duplicate request caches - DRCs),		caches (also known as duplicate request caches - DRCs),
	the slot ID-based reply cache cannot be overflowed.		the slot ID-based reply cache cannot be overflowed.
	Through use of the sequence ID to identify		Through use of the sequence ID to identify
	retransmitted requests, the replier does not need to		retransmitted requests, the replier does not need to
	actually cache the request itself, reducing the		actually cache the request itself, reducing the
	storage requirements of the reply cache further. These		storage requirements of the reply cache further. These
	facilities make it practical to maintain all the		facilities make it practical to maintain all the
	required entries for an effective reply cache.		required entries for an effective reply cache.
	</t>		</t>
	<t>		<t>
	The slot ID, sequence ID, and session ID therefore take over the traditiona l role		The slot ID, sequence ID, and session ID therefore take over the traditiona l role
	of the XID and source network address in the replier's		of the XID and source network address in the replier's
	reply cache implementation.		reply cache implementation.
	This approach is considerably		This approach is considerably
	more portable and completely robust -- it is not subject to the		more portable and completely robust -- it is not subject to the
	reassignment of ports as clients reconnect over IP		reassignment of ports as clients reconnect over IP
	networks. In addition, the RPC XID is not used in the reply cache,		networks. In addition, the RPC XID is not used in the reply cache,
	enhancing robustness of the cache in the face of any rapid reuse of		enhancing robustness of the cache in the face of any rapid reuse of
	XIDs by the requester. While the replier does not care		XIDs by the requester. While the replier does not care
	about the XID for the purposes of reply cache management		about the XID for the purposes of reply cache management
	(but the replier MUST return the same XID that was in the request),		(but the replier <bcp14>MUST</bcp14> return the same XID that was in the re quest),
	nonetheless there are considerations for the XID in NFSv4.1		nonetheless there are considerations for the XID in NFSv4.1
	that are the same as all other previous versions of NFS.		that are the same as all other previous versions of NFS.
	The RPC XID remains in each message and needs to be formulated		The RPC XID remains in each message and needs to be formulated
	in NFSv4.1 requests as in any other ONC RPC request. The reasons		in NFSv4.1 requests as in any other ONC RPC request. The reasons
	include:		include:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The RPC layer retains its existing semantics and implementation.		The RPC layer retains its existing semantics and implementation.
	</t>		</li>
	<t>		<li>
	The requester and replier must be able to interoperate at the		The requester and replier must be able to interoperate at the
	RPC layer, prior to the NFSv4.1 decoding of the SEQUENCE or CB_SEQUENCE		RPC layer, prior to the NFSv4.1 decoding of the SEQUENCE or CB_SEQUENCE
	operation.		operation.
	</t>		</li>
	<t>		<li>
	If an operation is being used that does not start with		If an operation is being used that does not start with
	SEQUENCE or CB_SEQUENCE (e.g., BIND_CONN_TO_SESSION),		SEQUENCE or CB_SEQUENCE (e.g., BIND_CONN_TO_SESSION),
	then the RPC XID is needed for correct operation to		then the RPC XID is needed for correct operation to
	match the reply to the request.		match the reply to the request.
	</t>		</li>
	<t>		<li>
	The SEQUENCE or CB_SEQUENCE operation may generate an error.		The SEQUENCE or CB_SEQUENCE operation may generate an error.
	If so, the embedded slot ID, sequence ID, and session ID (if		If so, the embedded slot ID, sequence ID, and session ID (if
	present) in the request will not be in the reply, and the		present) in the request will not be in the reply, and the
	requester has only the XID to match the reply to the request.		requester has only the XID to match the reply to the request.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Given that well-formulated XIDs continue to be required,		Given that well-formulated XIDs continue to be required,
	this raises the question: why do SEQUENCE and CB_SEQUENCE replies		this raises the question: why do SEQUENCE and CB_SEQUENCE replies
	have a session ID, slot ID, and sequence ID? Having the session ID		have a session ID, slot ID, and sequence ID? Having the session ID
	in the reply means that the requester does not have to use the		in the reply means that the requester does not have to use the
	XID to look up		XID to look up
	the session ID, which would be necessary if the connection were		the session ID, which would be necessary if the connection were
	associated with multiple sessions. Having the slot ID and sequence ID		associated with multiple sessions. Having the slot ID and sequence ID
	in the reply means that the requester does not have to use the XID to		in the reply means that the requester does not have to use the XID to
	look up the slot ID and sequence ID.		look up the slot ID and sequence ID.
	Furthermore, since the XID is only 32 bits, it is too small to		Furthermore, since the XID is only 32 bits, it is too small to
	guarantee the re-association of a reply with its request		guarantee the re-association of a reply with its request
	<xref target="rpc_xid_issues" />; having		<xref target="rpc_xid_issues" format="default"/>; having
	session ID, slot ID, and sequence ID in the reply allows the		session ID, slot ID, and sequence ID in the reply allows the
	client to validate that the reply in fact belongs to the matched request.		client to validate that the reply in fact belongs to the matched request.
	</t>		</t>
	<t>		<t>
	The SEQUENCE (and CB_SEQUENCE) operation also carries		The SEQUENCE (and CB_SEQUENCE) operation also carries
	a "highest_slotid" value, which carries additional		a "highest_slotid" value, which carries additional
	requester slot usage information. The requester MUST		requester slot usage information. The requester <bcp14>MUST</bcp14>
	always indicate the slot ID representing the outstanding request with the		always indicate the slot ID representing the outstanding request with the
	highest-numbered slot		highest-numbered slot
	value.		value.
	The requester should in all cases provide the most		The requester should in all cases provide the most
	conservative value possible, although it can be increased somewhat		conservative value possible, although it can be increased somewhat
	above the actual instantaneous usage to maintain some minimum or		above the actual instantaneous usage to maintain some minimum or
	optimal level. This provides a way for the requester to yield unused		optimal level. This provides a way for the requester to yield unused
	request slots back to the replier, which in turn can use the		request slots back to the replier, which in turn can use the
	information to reallocate resources.		information to reallocate resources.
	</t>		</t>
	<t>		<t>
	The replier		The replier
	responds with both a new target highest_slotid and an		responds with both a new target highest_slotid and an
	enforced highest_slotid, described as follows:		enforced highest_slotid, described as follows:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	The target highest_slotid is		The target highest_slotid is
	an indication to the requester of the highest_slotid the replier		an indication to the requester of the highest_slotid the replier
	wishes the requester to be using. This permits the replier to withdraw		wishes the requester to be using. This permits the replier to withdraw
	(or add) resources from a requester that has been found to not be		(or add) resources from a requester that has been found to not be
	using them, in order to more fairly share resources among a varying		using them, in order to more fairly share resources among a varying
	level of demand from other requesters. The requester must always comply		level of demand from other requesters. The requester must always comply
	with the replier's value updates, since they indicate newly		with the replier's value updates, since they indicate newly
	established hard limits on the requester's access to session		established hard limits on the requester's access to session
	resources. However, because of request pipelining, the requester may		resources. However, because of request pipelining, the requester may
	have active requests in flight reflecting prior values; therefore,		have active requests in flight reflecting prior values; therefore,
	the replier must not immediately require the requester to comply.		the replier must not immediately require the requester to comply.
	<vspace blankLines='1' />		</t>
	</t>		</li>
	<t>		<li>
			<t>
	The enforced highest_slotid indicates the highest slot ID		The enforced highest_slotid indicates the highest slot ID
	the requester is permitted to use on a subsequent SEQUENCE or		the requester is permitted to use on a subsequent SEQUENCE or
	CB_SEQUENCE operation. The replier's enforced highest_slotid SHOULD		CB_SEQUENCE operation. The replier's enforced highest_slotid <bcp14>SHOULD </bcp14>
	be no less than the highest_slotid the requester indicated		be no less than the highest_slotid the requester indicated
	in the SEQUENCE or CB_SEQUENCE arguments.		in the SEQUENCE or CB_SEQUENCE arguments.
	<vspace blankLines='1' />		</t>
			<t>
	A requester can be intransigent with respect to lowering its		A requester can be intransigent with respect to lowering its
	highest_slotid argument to a Sequence operation, i.e. the requester		highest_slotid argument to a Sequence operation, i.e. the requester
	continues to ignore the target highest_slotid in the response to		continues to ignore the target highest_slotid in the response to
	a Sequence operation, and continues to set its highest_slotid		a Sequence operation, and continues to set its highest_slotid
	argument to be higher than the target highest_slotid. This can		argument to be higher than the target highest_slotid. This can
	be considered particularly egregious behavior when the replier		be considered particularly egregious behavior when the replier
	knows there are no outstanding requests with slot IDs higher than		knows there are no outstanding requests with slot IDs higher than
	its target highest_slotid. When faced with such intransigence,		its target highest_slotid. When faced with such intransigence,
	the replier is free to take more forceful action, and MAY reply with		the replier is free to take more forceful action, and <bcp14>MAY</bcp14> r eply with
	a new enforced highest_slotid that is less than its previous		a new enforced highest_slotid that is less than its previous
	enforced highest_slotid. Thereafter, if the requester continues		enforced highest_slotid. Thereafter, if the requester continues
	to send requests with a highest_slotid that is greater than		to send requests with a highest_slotid that is greater than
	the replier's new enforced highest_slotid, the server MAY return		the replier's new enforced highest_slotid, the server <bcp14>MAY</bcp14> r eturn
	NFS4ERR_BAD_HIGH_SLOT, unless the slot ID in the request is greater		NFS4ERR_BAD_HIGH_SLOT, unless the slot ID in the request is greater
	than the new enforced highest_slotid and the request is a retry.		than the new enforced highest_slotid and the request is a retry.
	<vspace blankLines='1' />		</t>
			<t>
	The replier SHOULD retain the slots it wants to retire		The replier <bcp14>SHOULD</bcp14> retain the slots it wants to retire
	until		until
	the requester sends a request with a highest_slotid less than		the requester sends a request with a highest_slotid less than
	or equal to the replier's new enforced highest_slotid.		or equal to the replier's new enforced highest_slotid.
	<vspace blankLines='1' />		</t>
			<t>
	The requester can also be intransigent with		The requester can also be intransigent with
	respect to sending non-retry requests that have a slot ID that		respect to sending non-retry requests that have a slot ID that
	exceeds the replier's highest_slotid.		exceeds the replier's highest_slotid.
	Once the replier has forcibly lowered the enforced		Once the replier has forcibly lowered the enforced
	highest_slotid, the requester is only allowed to		highest_slotid, the requester is only allowed to
	send retries on slots that exceed the replier's highest_slotid.		send retries on slots that exceed the replier's highest_slotid.
	If a request is received with a slot ID that is higher than		If a request is received with a slot ID that is higher than
	the new enforced highest_slotid, and the sequence ID		the new enforced highest_slotid, and the sequence ID
	is one higher than what is in the slot's reply cache, then		is one higher than what is in the slot's reply cache, then
	the server can both retire the slot and return NFS4ERR_BADSLOT		the server can both retire the slot and return NFS4ERR_BADSLOT
	(however, the server MUST NOT do one and not the other).		(however, the server <bcp14>MUST NOT</bcp14> do one and not the other).
	The reason it is safe to retire the slot		The reason it is safe to retire the slot
	is because by using the next sequence ID, the requester		is because by using the next sequence ID, the requester
	is indicating it has received the previous reply for the		is indicating it has received the previous reply for the
	slot.		slot.
	<vspace blankLines='1' />		</t>
	</t>		</li>
	<t>		<li>
	The requester SHOULD use the lowest available		The requester <bcp14>SHOULD</bcp14> use the lowest available
	slot when sending a new request. This way, the		slot when sending a new request. This way, the
	replier may be able to retire slot entries faster.		replier may be able to retire slot entries faster.
	However, where the replier is actively adjusting		However, where the replier is actively adjusting
	its granted highest_slotid,		its granted highest_slotid,
	it will not be able		it will not be able
	to use only the receipt of the slot ID and highest_slotid		to use only the receipt of the slot ID and highest_slotid
	in the request. Neither the slot ID nor the		in the request. Neither the slot ID nor the
	highest_slotid used in a request may reflect the		highest_slotid used in a request may reflect the
	replier's current idea of the requester's session		replier's current idea of the requester's session
	limit, because the request may have been sent from the		limit, because the request may have been sent from the
	requester before the update was received. Therefore,		requester before the update was received. Therefore,
	in the downward adjustment case, the replier may have		in the downward adjustment case, the replier may have
	to retain a number of reply cache entries at least as		to retain a number of reply cache entries at least as
	large as the old value of maximum requests		large as the old value of maximum requests
	outstanding, until it can infer that the requester		outstanding, until it can infer that the requester
	has seen a reply containing the new granted highest_slotid.		has seen a reply containing the new granted highest_slotid.
	The replier can infer that the requester has seen such a		The replier can infer that the requester has seen such a
	reply when it receives a new request with the same		reply when it receives a new request with the same
	slot ID as the request replied to and the next higher		slot ID as the request replied to and the next higher
	sequence ID.		sequence ID.
	</t>		</li>
	</list>		</ul>
	</t>		<section anchor="cacheseq" numbered="true" toc="default">
	<section title="Caching of SEQUENCE and CB_SEQUENCE Replies" anchor="caches		<name>Caching of SEQUENCE and CB_SEQUENCE Replies</name>
	eq">		<t>
	<t>
	When a SEQUENCE or CB_SEQUENCE operation is		When a SEQUENCE or CB_SEQUENCE operation is
	successfully executed, its reply MUST always be		successfully executed, its reply <bcp14>MUST</bcp14> always be
	cached. Specifically, session ID, sequence ID,		cached. Specifically, session ID, sequence ID,
	and slot ID MUST be cached in the reply cache.		and slot ID <bcp14>MUST</bcp14> be cached in the reply cache.
	The reply from SEQUENCE also includes the highest		The reply from SEQUENCE also includes the highest
	slot ID, target highest slot ID, and status flags. Instead		slot ID, target highest slot ID, and status flags. Instead
	of caching these values, the server MAY		of caching these values, the server <bcp14>MAY</bcp14>
	re-compute the values from the current		re-compute the values from the current
	state of the fore channel, session, and/or client		state of the fore channel, session, and/or client
	ID as appropriate. Similarly, the reply from		ID as appropriate. Similarly, the reply from
	CB_SEQUENCE includes a highest slot ID and target		CB_SEQUENCE includes a highest slot ID and target
	highest slot ID. The client		highest slot ID. The client
	MAY re-compute the values from the		<bcp14>MAY</bcp14> re-compute the values from the
	current state of the session as appropriate.		current state of the session as appropriate.
	</t>		</t>
			<t>
	<t>
	Regardless of whether or not a replier is re-computing highest slot ID,		Regardless of whether or not a replier is re-computing highest slot ID,
	target slot ID, and status on replies to retries, the requester		target slot ID, and status on replies to retries, the requester
	MUST NOT assume that the values are being re-computed whenever it		<bcp14>MUST NOT</bcp14> assume that the values are being re-computed when ever it
	receives a reply after a retry is sent, since it has no way		receives a reply after a retry is sent, since it has no way
	of knowing whether the reply it has received was sent by the		of knowing whether the reply it has received was sent by the
	replier in response to the retry or is a delayed response to		replier in response to the retry or is a delayed response to
	the original request. Therefore, it may be the case that		the original request. Therefore, it may be the case that
	highest slot ID, target slot ID, or status bits may reflect		highest slot ID, target slot ID, or status bits may reflect
	the state of affairs when the request was first executed.		the state of affairs when the request was first executed.
	Although acting based on such delayed information is valid,		Although acting based on such delayed information is valid,
	it may cause the receiver of the reply to do unneeded work. Requesters		it may cause the receiver of the reply to do unneeded work. Requesters
	MAY choose to send additional requests to get the current		<bcp14>MAY</bcp14> choose to send additional requests to get the current
	state of affairs or use the state of affairs reported by		state of affairs or use the state of affairs reported by
	subsequent requests, in preference to acting immediately		subsequent requests, in preference to acting immediately
	on data that might be out of date.		on data that might be out of date.
	</t>		</t>
			</section>
	</section>		<section anchor="err_sequence" numbered="true" toc="default">
			<name>Errors from SEQUENCE and CB_SEQUENCE</name>
	<section title="Errors from SEQUENCE and CB_SEQUENCE"		<t>
	anchor="err_sequence">
	<t>
	Any time SEQUENCE or CB_SEQUENCE returns an error, the		Any time SEQUENCE or CB_SEQUENCE returns an error, the
	sequence ID of the slot MUST NOT change. The replier MUST NOT		sequence ID of the slot <bcp14>MUST NOT</bcp14> change. The replier <bcp14 >MUST NOT</bcp14>
	modify the reply cache entry for the slot whenever an error		modify the reply cache entry for the slot whenever an error
	is returned from SEQUENCE or CB_SEQUENCE.		is returned from SEQUENCE or CB_SEQUENCE.
	</t>		</t>
	</section> <!-- Errors from SEQUENCE and CB_SEQUENCE -->		</section>
	<section title="Optional Reply Caching"		<section anchor="optional_reply_caching" numbered="true" toc="default">
	anchor="optional_reply_caching">		<name>Optional Reply Caching</name>
	<t>		<t>
	On a per-request basis, the requester can choose to		On a per-request basis, the requester can choose to
	direct the replier to cache the reply to all operations		direct the replier to cache the reply to all operations
	after the first operation (SEQUENCE or CB_SEQUENCE) via		after the first operation (SEQUENCE or CB_SEQUENCE) via
	the sa_cachethis or csa_cachethis fields of the arguments		the sa_cachethis or csa_cachethis fields of the arguments
	to SEQUENCE or CB_SEQUENCE.		to SEQUENCE or CB_SEQUENCE.
	The reason it would not direct the replier to cache		The reason it would not direct the replier to cache
	the entire reply is that the request is composed of all		the entire reply is that the request is composed of all
	idempotent operations <xref target="Chet" />.		idempotent operations <xref target="Chet" format="default"/>.
	Caching the reply may offer little benefit. If		Caching the reply may offer little benefit. If
	the reply is too large (see		the reply is too large (see
	<xref target="COMPOUND_Sizing_Issues" />),		<xref target="COMPOUND_Sizing_Issues" format="default"/>),
	it may not be cacheable anyway. Even if the reply to		it may not be cacheable anyway. Even if the reply to
	idempotent request is small enough to cache, unnecessarily		idempotent request is small enough to cache, unnecessarily
	caching the reply slows down the server and increases		caching the reply slows down the server and increases
	RPC latency.		RPC latency.
	</t>		</t>
	<t>		<t>
	Whether or not the requester requests the reply to be cached		Whether or not the requester requests the reply to be cached
	has no effect on the slot processing. If the		has no effect on the slot processing. If the
	result of SEQUENCE or CB_SEQUENCE is NFS4_OK, then		result of SEQUENCE or CB_SEQUENCE is NFS4_OK, then
	the slot's sequence ID MUST be incremented by one.		the slot's sequence ID <bcp14>MUST</bcp14> be incremented by one.
	If a requester does not direct the replier to cache		If a requester does not direct the replier to cache
	the reply, the replier MUST do one of following:		the reply, the replier <bcp14>MUST</bcp14> do one of following:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	The replier can cache the entire original reply.		The replier can cache the entire original reply.
	Even though sa_cachethis or csa_cachethis is FALSE,		Even though sa_cachethis or csa_cachethis is FALSE,
	the replier is always free to cache. It may choose		the replier is always free to cache. It may choose
	this approach in order to simplify implementation.		this approach in order to simplify implementation.
	</t>		</li>
	<t>		<li>
			<t>
	The replier enters into its reply cache a reply consisting		The replier enters into its reply cache a reply consisting
	of the original results to the SEQUENCE or CB_SEQUENCE		of the original results to the SEQUENCE or CB_SEQUENCE
	operation, and with the next operation in		operation, and with the next operation in
	COMPOUND or CB_COMPOUND having the error NFS4ERR_RETRY_UNCACHED_REP.		COMPOUND or CB_COMPOUND having the error NFS4ERR_RETRY_UNCACHED_REP.
	Thus, if the requester later retries the request, it will		Thus, if the requester later retries the request, it will
	get NFS4ERR_RETRY_UNCACHED_REP.		get NFS4ERR_RETRY_UNCACHED_REP.
	If a replier receives a retried Sequence operation where the reply		If a replier receives a retried Sequence operation where the reply
	to the COMPOUND or CB_COMPOUND was not cached, then the replier,		to the COMPOUND or CB_COMPOUND was not cached, then the replier,
	<list style='symbols'>		</t>
			<ul spacing="normal">
	<t>		<li>
	MAY return NFS4ERR_RETRY_UNCACHED_REP		<bcp14>MAY</bcp14> return NFS4ERR_RETRY_UNCACHED_REP
	in reply to a Sequence operation if the		in reply to a Sequence operation if the
	Sequence operation is not the first		Sequence operation is not the first
	operation (granted, a requester that		operation (granted, a requester that
	does so is in violation of the NFSv4.1		does so is in violation of the NFSv4.1
	protocol).		protocol).
	</t>		</li>
			<li>
	<t>		<bcp14>MUST NOT</bcp14> return
	MUST NOT return
	NFS4ERR_RETRY_UNCACHED_REP in reply to		NFS4ERR_RETRY_UNCACHED_REP in reply to
	a Sequence operation if the Sequence		a Sequence operation if the Sequence
	operation is the first operation.		operation is the first operation.
	</t>		</li>
			</ul>
	</list>		</li>
			<li>
	</t>
	<t>
	If the second operation is an illegal operation, or an		If the second operation is an illegal operation, or an
	operation that was legal in a previous minor version of		operation that was legal in a previous minor version of
	NFSv4 and MUST NOT		NFSv4 and <bcp14>MUST NOT</bcp14>
	be supported in the current minor version (e.g., SETCLIENTID), the		be supported in the current minor version (e.g., SETCLIENTID), the
	replier MUST NOT ever return NFS4ERR_RETRY_UNCACHED_REP.		replier <bcp14>MUST NOT</bcp14> ever return NFS4ERR_RETRY_UNCACHED_REP.
	Instead the replier MUST return NFS4ERR_OP_ILLEGAL or		Instead the replier <bcp14>MUST</bcp14> return NFS4ERR_OP_ILLEGAL or
	NFS4ERR_BADXDR or NFS4ERR_NOTSUPP as appropriate.		NFS4ERR_BADXDR or NFS4ERR_NOTSUPP as appropriate.
	</t>		</li>
			<li>
	<t>
	If the second operation can result in another error status,		If the second operation can result in another error status,
	the replier MAY return a status other than NFS4ERR_RETRY_UNCACHED_REP,		the replier <bcp14>MAY</bcp14> return a status other than NFS4ERR_RETRY_ UNCACHED_REP,
	provided the operation is not executed in such a way that the state		provided the operation is not executed in such a way that the state
	of the replier is changed. Examples of such		of the replier is changed. Examples of such
	an error status include: NFS4ERR_NOTSUPP returned for an		an error status include: NFS4ERR_NOTSUPP returned for an
	operation that is legal but not REQUIRED in the current		operation that is legal but not <bcp14>REQUIRED</bcp14> in the current
	minor versions, and thus not supported by the replier;		minor versions, and thus not supported by the replier;
	NFS4ERR_SEQUENCE_POS; and NFS4ERR_REQ_TOO_BIG.		NFS4ERR_SEQUENCE_POS; and NFS4ERR_REQ_TOO_BIG.
	</t>		</li>
			</ul>
	</list>		<t>
	</t>
	<t>
	The discussion above assumes that the		The discussion above assumes that the
	retried request matches the original		retried request matches the original
	one. <xref target="false_retry"/>		one. <xref target="false_retry" format="default"/>
	discusses what the replier might do, and		discusses what the replier might do, and
	MUST do when original and retried requests do not match.		<bcp14>MUST</bcp14> do when original and retried requests do not match.
	Since the replier may		Since the replier may
	only cache a small amount of the		only cache a small amount of the
	information that would be required to		information that would be required to
	determine whether this is a case of a		determine whether this is a case of a
	false retry, the replier may send to the		false retry, the replier may send to the
	client any of the following responses:		client any of the following responses:
	<list style='symbols'>		</t>
			<ul spacing="normal">
	<t>		<li>
	The cached reply to the original request (if the replier has cached		The cached reply to the original request (if the replier has cached
	it in its entirety and the users of the original request and retry matc h).		it in its entirety and the users of the original request and retry matc h).
	</t>		</li>
			<li>
	<t>
	A reply that consists only of the Sequence operation with the error		A reply that consists only of the Sequence operation with the error
	NFS4ERR_FALSE_RETRY.		NFS4ERR_SEQ_FALSE_RETRY.
	</t>		</li>
			<li>
	<t>
	A reply consisting of the response to Sequence with the status		A reply consisting of the response to Sequence with the status
	NFS4_OK, together with the second operation as it appeared in the retried		NFS4_OK, together with the second operation as it appeared in the retried
	request with an error of NFS4ERR_RETRY_UNCACHED_REP or other error as		request with an error of NFS4ERR_RETRY_UNCACHED_REP or other error as
	described above.		described above.
	</t>		</li>
			<li>
	<t>
	A reply that consists of the response to Sequence with the status		A reply that consists of the response to Sequence with the status
	NFS4_OK, together with the second operation as it appeared in the origina l		NFS4_OK, together with the second operation as it appeared in the origina l
	request with an error of NFS4ERR_RETRY_UNCACHED_REP or other error as		request with an error of NFS4ERR_RETRY_UNCACHED_REP or other error as
	described above.		described above.
	</t>		</li>
	</list>		</ul>
			<section anchor="false_retry" numbered="true" toc="default">
	</t>		<name>False Retry</name>
			<t>
	<section anchor="false_retry" title="False Retry">
	<t>
	If a requester sent a Sequence operation		If a requester sent a Sequence operation
	with a slot ID and sequence ID that are		with a slot ID and sequence ID that are
	in the reply cache but the replier		in the reply cache but the replier
	detected that the retried request is not		detected that the retried request is not
	the same as the original request,		the same as the original request,
	including a retry that has different		including a retry that has different
	operations or different arguments in the		operations or different arguments in the
	operations from the original and a retry		operations from the original and a retry
	that uses a different principal in the		that uses a different principal in the
	RPC request's credential field that		RPC request's credential field that
	translates to a different user, then this		translates to a different user, then this
	is a false retry. When the replier		is a false retry. When the replier
	detects a false retry, it is permitted		detects a false retry, it is permitted
	(but not always obligated) to return		(but not always obligated) to return
	NFS4ERR_FALSE_RETRY in response to the		NFS4ERR_SEQ_FALSE_RETRY in response to the
	Sequence operation when it detects a		Sequence operation when it detects a
	false retry.		false retry.
	</t>		</t>
			<t>
	<t>
	Translations of particularly privileged		Translations of particularly privileged
	user values to other users due to the		user values to other users due to the
	lack of appropriately secure credentials,		lack of appropriately secure credentials,
	as configured on the replier, should be		as configured on the replier, should be
	applied before determining whether the		applied before determining whether the
	users are the same or different. If the		users are the same or different. If the
	replier determines the users are		replier determines the users are
	different between the original request		different between the original request
	and a retry, then the replier MUST return		and a retry, then the replier <bcp14>MUST</bcp14> return
	NFS4ERR_FALSE_RETRY.		NFS4ERR_SEQ_FALSE_RETRY.
	</t>
	<t>		</t>
			<t>
	If an operation of the retry is an		If an operation of the retry is an
	illegal operation, or an operation that		illegal operation, or an operation that
	was legal in a previous minor version of		was legal in a previous minor version of
	NFSv4 and MUST NOT be supported in the		NFSv4 and <bcp14>MUST NOT</bcp14> be supported in the
	current minor version (e.g., SETCLIENTID),		current minor version (e.g., SETCLIENTID),
	the replier MAY return		the replier <bcp14>MAY</bcp14> return
	NFS4ERR_FALSE_RETRY (and MUST do so if		NFS4ERR_SEQ_FALSE_RETRY (and <bcp14>MUST</bcp14> do so if
	the users of the original request and		the users of the original request and
	retry differ). Otherwise, the replier MAY return		retry differ). Otherwise, the replier <bcp14>MAY</bcp14> return
	NFS4ERR_OP_ILLEGAL or NFS4ERR_BADXDR or		NFS4ERR_OP_ILLEGAL or NFS4ERR_BADXDR or
	NFS4ERR_NOTSUPP as appropriate. Note		NFS4ERR_NOTSUPP as appropriate. Note
	that the handling is in contrast for how the		that the handling is in contrast for how the
	replier deals with retries requests with		replier deals with retries requests with
	no cached reply. The difference is due to		no cached reply. The difference is due to
	NFS4ERR_FALSE_RETRY being a valid error		NFS4ERR_SEQ_FALSE_RETRY being a valid error
	for only Sequence operations, whereas		for only Sequence operations, whereas
	NFS4ERR_RETRY_UNCACHED_REP is a valid		NFS4ERR_RETRY_UNCACHED_REP is a valid
	error for all operations except illegal		error for all operations except illegal
	operations and operations that MUST NOT be		operations and operations that <bcp14>MUST NOT</bcp14> be
	supported in the current minor version of		supported in the current minor version of
	NFSv4.		NFSv4.
	</t>		</t>
	</section>		</section>
			</section>
	</section> <!-- Optional Reply Caching -->		</section>
	</section> <!-- Slot Identifiers and Server Reply Cache -->
	<section anchor="Retry_and_Replay" title="Retry and Replay of Reply">		<section anchor="Retry_and_Replay" numbered="true" toc="default">
	<t>		<name>Retry and Replay of Reply</name>
	A requester MUST NOT retry a request, unless		<t>
			A requester <bcp14>MUST NOT</bcp14> retry a request, unless
	the connection it used to send the request		the connection it used to send the request
	disconnects. The requester can then reconnect		disconnects. The requester can then reconnect
	and re-send the request, or it can re-send the		and re-send the request, or it can re-send the
	request over a different connection that is		request over a different connection that is
	associated with the same session.		associated with the same session.
	</t>		</t>
	<t>		<t>
	If the requester is a server wanting to re-send a callback		If the requester is a server wanting to re-send a callback
	operation over the backchannel of a session, the requester		operation over the backchannel of a session, the requester
	of course cannot reconnect because only the client can		of course cannot reconnect because only the client can
	associate connections with the backchannel. The		associate connections with the backchannel. The
	server can re-send the request over another connection that		server can re-send the request over another connection that
	is bound to the same session's backchannel. If there is no		is bound to the same session's backchannel. If there is no
	such connection, the server		such connection, the server
	MUST indicate that the session has no backchannel by setting		<bcp14>MUST</bcp14> indicate that the session has no backchannel by setting
	the SEQ4_STATUS_CB_PATH_DOWN_SESSION flag bit in the response		the SEQ4_STATUS_CB_PATH_DOWN_SESSION flag bit in the response
	to the next SEQUENCE operation from the client. The client MUST		to the next SEQUENCE operation from the client. The client <bcp14>MUST</bcp 14>
	then associate a connection with the session (or destroy		then associate a connection with the session (or destroy
	the session).		the session).
	</t>		</t>
	<t>		<t>
	Note that it is not fatal for a requester to retry		Note that it is not fatal for a requester to retry
	without a disconnect between the request and retry.		without a disconnect between the request and retry.
	However, the retry does consume resources, especially		However, the retry does consume resources, especially
	with RDMA, where each request, retry or not, consumes		with RDMA, where each request, retry or not, consumes
	a credit. Retries for no reason, especially retries		a credit. Retries for no reason, especially retries
	sent shortly after the previous attempt, are a poor		sent shortly after the previous attempt, are a poor
	use of network bandwidth and defeat the purpose of a		use of network bandwidth and defeat the purpose of a
	transport's inherent congestion control system.		transport's inherent congestion control system.
	</t>		</t>
	<t>		<t>
	A requester MUST wait for a reply to a request before using		A requester <bcp14>MUST</bcp14> wait for a reply to a request before using
	the slot for another request. If it does not wait for		the slot for another request. If it does not wait for
	a reply, then the requester does not know what		a reply, then the requester does not know what
	sequence ID to use for the slot on its next request.		sequence ID to use for the slot on its next request.
	For example, suppose a requester sends a request with sequence ID		For example, suppose a requester sends a request with sequence ID
	1, and does not wait for the response. The next time it uses		1, and does not wait for the response. The next time it uses
	the slot, it sends the new request with sequence ID 2.		the slot, it sends the new request with sequence ID 2.
	If the replier has not seen the request with sequence ID 1, then		If the replier has not seen the request with sequence ID 1, then
	the replier is not expecting sequence ID 2, and rejects the		the replier is not expecting sequence ID 2, and rejects the
	requester's new request with NFS4ERR_SEQ_MISORDERED (as the		requester's new request with NFS4ERR_SEQ_MISORDERED (as the
	result from SEQUENCE or CB_SEQUENCE).		result from SEQUENCE or CB_SEQUENCE).
	</t>		</t>
	<t>		<t>
	RDMA fabrics do not guarantee that the memory handles		RDMA fabrics do not guarantee that the memory handles
	(Steering Tags) within each RPC/RDMA "chunk" <xref target="RFC8166" />		(Steering Tags) within each RPC/RDMA "chunk" <xref target="RFC8166" format= "default"/>
	are valid on a scope		are valid on a scope
	outside that of a single connection. Therefore, handles used by		outside that of a single connection. Therefore, handles used by
	the direct operations become invalid after connection loss. The		the direct operations become invalid after connection loss. The
	server must ensure that any RDMA operations that must be replayed		server must ensure that any RDMA operations that must be replayed
	from the reply cache use the newly provided handle(s) from the		from the reply cache use the newly provided handle(s) from the
	most recent request.		most recent request.
	</t>		</t>
	<t>		<t>
	A retry might be sent while the original request is still in		A retry might be sent while the original request is still in
	progress on the replier. The replier SHOULD deal with the issue		progress on the replier. The replier <bcp14>SHOULD</bcp14> deal with the is sue
	by returning NFS4ERR_DELAY as the reply to SEQUENCE or CB_SEQUENCE		by returning NFS4ERR_DELAY as the reply to SEQUENCE or CB_SEQUENCE
	operation, but implementations MAY return NFS4ERR_MISORDERED.		operation, but implementations <bcp14>MAY</bcp14> return NFS4ERR_MISORDERED .
	Since errors from SEQUENCE and CB_SEQUENCE are		Since errors from SEQUENCE and CB_SEQUENCE are
	never recorded in the reply cache, this approach allows the		never recorded in the reply cache, this approach allows the
	results of the execution of the original request to be		results of the execution of the original request to be
	properly recorded in the reply cache (assuming that the requester		properly recorded in the reply cache (assuming that the requester
	specified the reply to be cached).		specified the reply to be cached).
	</t>		</t>
			</section>
	</section> <!-- Retry and Replay -->
	<section anchor="sessions_callback_races" title="Resolving Server Callback R		<section anchor="sessions_callback_races" numbered="true" toc="default">
	aces">		<name>Resolving Server Callback Races</name>
	<t>		<t>
	It is possible for server callbacks to arrive at the		It is possible for server callbacks to arrive at the
	client before the reply from related fore channel		client before the reply from related fore channel
	operations. For example, a client may have been		operations. For example, a client may have been
	granted a delegation to a file it has opened, but the		granted a delegation to a file it has opened, but the
	reply to the OPEN (informing the client of the		reply to the OPEN (informing the client of the
	granting of the delegation) may be delayed in the		granting of the delegation) may be delayed in the
	network. If a conflicting operation arrives at the		network. If a conflicting operation arrives at the
	server, it will recall the delegation using the		server, it will recall the delegation using the
	backchannel, which may be on a different		backchannel, which may be on a different
	transport connection, perhaps even a different		transport connection, perhaps even a different
	network, or even a different session associated with		network, or even a different session associated with
	the same client ID.		the same client ID.
	</t>		</t>
	<t>		<t>
	The presence of a session between the client and server		The presence of a session between the client and server
	alleviates this issue. When a session is in place,		alleviates this issue. When a session is in place,
	each client request is uniquely identified by its {		each client request is uniquely identified by its {
	session ID, slot ID, sequence ID } triple. By the rules under which		session ID, slot ID, sequence ID } triple. By the rules under which
	slot entries (reply cache entries) are		slot entries (reply cache entries) are
	retired, the server has knowledge whether the client		retired, the server has knowledge whether the client
	has "seen" each of the server's replies. The server		has "seen" each of the server's replies. The server
	can therefore provide sufficient information to the		can therefore provide sufficient information to the
	client to allow it to disambiguate between an		client to allow it to disambiguate between an
	erroneous or conflicting callback race		erroneous or conflicting callback race
	condition.		condition.
	</t>		</t>
	<t>		<t>
	For each client operation that might result in some		For each client operation that might result in some
	sort of server callback, the server SHOULD "remember"		sort of server callback, the server <bcp14>SHOULD</bcp14> "remember"
	the { session ID, slot ID, sequence ID } triple of the client request		the { session ID, slot ID, sequence ID } triple of the client request
	until the slot ID retirement rules allow the server to		until the slot ID retirement rules allow the server to
	determine that the client has, in fact, seen the		determine that the client has, in fact, seen the
	server's reply. Until the time the { session ID, slot ID,		server's reply. Until the time the { session ID, slot ID,
	sequence ID } request triple can be retired, any recalls		sequence ID } request triple can be retired, any recalls
	of the associated object MUST carry an array of these		of the associated object <bcp14>MUST</bcp14> carry an array of these
	referring identifiers (in the CB_SEQUENCE operation's		referring identifiers (in the CB_SEQUENCE operation's
	arguments), for the benefit of the client. After this		arguments), for the benefit of the client. After this
	time, it is not necessary for the server to provide		time, it is not necessary for the server to provide
	this information in related callbacks, since it is		this information in related callbacks, since it is
	certain that a race condition can no longer occur.		certain that a race condition can no longer occur.
	</t>		</t>
	<t>		<t>
	The CB_SEQUENCE operation that begins each server		The CB_SEQUENCE operation that begins each server
	callback carries a list of "referring" { session ID, slot ID,		callback carries a list of "referring" { session ID, slot ID,
	sequence ID } triples. If the client finds the request		sequence ID } triples. If the client finds the request
	corresponding to the referring session ID, slot ID, and sequence ID		corresponding to the referring session ID, slot ID, and sequence ID
	to be currently outstanding (i.e., the server's reply has		to be currently outstanding (i.e., the server's reply has
	not been seen by the client), it can determine that		not been seen by the client), it can determine that
	the callback has raced the reply, and act		the callback has raced the reply, and act
	accordingly. If the client does not find the request		accordingly. If the client does not find the request
	corresponding to the referring triple to be outstanding (including		corresponding to the referring triple to be outstanding (including
	the case of a session ID referring to a destroyed session),		the case of a session ID referring to a destroyed session),
	then there is no race with respect to this triple.		then there is no race with respect to this triple.
	The server SHOULD limit the referring triples		The server <bcp14>SHOULD</bcp14> limit the referring triples
	to requests that refer to just those that apply to the objects		to requests that refer to just those that apply to the objects
	referred to in		referred to in
	the CB_COMPOUND procedure.		the CB_COMPOUND procedure.
	</t>		</t>
	<t>		<t>
	The client must not simply wait forever for the		The client must not simply wait forever for the
	expected server reply to arrive before responding to the		expected server reply to arrive before responding to the
	CB_COMPOUND that won the race,		CB_COMPOUND that won the race,
	because it is possible		because it is possible
	that it will be delayed indefinitely. The client should		that it will be delayed indefinitely. The client should
	assume the likely case that the reply will arrive within		assume the likely case that the reply will arrive within
	the average round-trip time for COMPOUND requests to the		the average round-trip time for COMPOUND requests to the
	server, and wait that period of time. If		server, and wait that period of time. If
	that period of time		that period of time
	expires, it can respond to the CB_COMPOUND with		expires, it can respond to the CB_COMPOUND with
	NFS4ERR_DELAY. There are other scenarios under which callbacks		NFS4ERR_DELAY. There are other scenarios under which callbacks
	may race replies.		may race replies.
	Among them are pNFS layout recalls as described in		Among them are pNFS layout recalls as described in
	<xref target="pnfs_operation_sequencing" />.		<xref target="pnfs_operation_sequencing" format="default"/>.
	</t>		</t>
	</section> <!-- Resolving server callback races with sessions -->		</section>
	<section anchor="COMPOUND_Sizing_Issues" title="COMPOUND and CB_COMPOUND Cons		<section anchor="COMPOUND_Sizing_Issues" numbered="true" toc="default">
	truction Issues">		<name>COMPOUND and CB_COMPOUND Construction Issues</name>
			<t>
	<t>
	Very large requests and replies may pose both buffer		Very large requests and replies may pose both buffer
	management issues (especially with RDMA) and reply		management issues (especially with RDMA) and reply
	cache issues. When the session is created		cache issues. When the session is created
	(<xref target="OP_CREATE_SESSION" />), for each channel (fore and		(<xref target="OP_CREATE_SESSION" format="default"/>), for each channel (for e and
	back), the client and server		back), the client and server
	negotiate the maximum-sized request they will		negotiate the maximum-sized request they will
	send or process (ca_maxrequestsize), the maximum-sized reply		send or process (ca_maxrequestsize), the maximum-sized reply
	they will return or process (ca_maxresponsesize), and the		they will return or process (ca_maxresponsesize), and the
	maximum-sized reply they will store in the reply cache		maximum-sized reply they will store in the reply cache
	(ca_maxresponsesize_cached).		(ca_maxresponsesize_cached).
	</t>		</t>
	<t>		<t>
	If a request exceeds ca_maxrequestsize, the reply will		If a request exceeds ca_maxrequestsize, the reply will
	have the status NFS4ERR_REQ_TOO_BIG. A replier MAY		have the status NFS4ERR_REQ_TOO_BIG. A replier <bcp14>MAY</bcp14>
	return NFS4ERR_REQ_TOO_BIG as the status for the first operation		return NFS4ERR_REQ_TOO_BIG as the status for the first operation
	(SEQUENCE or CB_SEQUENCE) in the request (which means that		(SEQUENCE or CB_SEQUENCE) in the request (which means that
	no operations in the request executed and that the		no operations in the request executed and that the
	state of the slot in the reply cache is unchanged), or it MAY		state of the slot in the reply cache is unchanged), or it <bcp14>MAY</bcp14>
	opt to return it on a subsequent operation in the same		opt to return it on a subsequent operation in the same
	COMPOUND or CB_COMPOUND request (which means that at least one		COMPOUND or CB_COMPOUND request (which means that at least one
	operation did execute and that the state of the slot in the reply cache does		operation did execute and that the state of the slot in the reply cache does
	change). The replier SHOULD set NFS4ERR_REQ_TOO_BIG on the		change). The replier <bcp14>SHOULD</bcp14> set NFS4ERR_REQ_TOO_BIG on the
	operation that exceeds ca_maxrequestsize.		operation that exceeds ca_maxrequestsize.
	</t>		</t>
	<t>		<t>
	If a reply exceeds ca_maxresponsesize, the reply will		If a reply exceeds ca_maxresponsesize, the reply will
	have the status NFS4ERR_REP_TOO_BIG. A replier MAY		have the status NFS4ERR_REP_TOO_BIG. A replier <bcp14>MAY</bcp14>
	return NFS4ERR_REP_TOO_BIG as the status for the first operation		return NFS4ERR_REP_TOO_BIG as the status for the first operation
	(SEQUENCE or CB_SEQUENCE) in the request, or it MAY		(SEQUENCE or CB_SEQUENCE) in the request, or it <bcp14>MAY</bcp14>
	opt to return it on a subsequent operation (in the same		opt to return it on a subsequent operation (in the same
	COMPOUND or CB_COMPOUND reply). A replier MAY return NFS4ERR_REP_TOO_BIG		COMPOUND or CB_COMPOUND reply). A replier <bcp14>MAY</bcp14> return NFS4ERR_ REP_TOO_BIG
	in the reply to SEQUENCE or CB_SEQUENCE, even if the response		in the reply to SEQUENCE or CB_SEQUENCE, even if the response
	would still exceed ca_maxresponsesize.		would still exceed ca_maxresponsesize.
	</t>		</t>
	<t>		<t>
	If sa_cachethis or csa_cachethis is TRUE, then the		If sa_cachethis or csa_cachethis is TRUE, then the
	replier MUST cache a reply except if an error is		replier <bcp14>MUST</bcp14> cache a reply except if an error is
	returned by the SEQUENCE or CB_SEQUENCE operation (see		returned by the SEQUENCE or CB_SEQUENCE operation (see
	<xref target="err_sequence" />). If the reply exceeds		<xref target="err_sequence" format="default"/>). If the reply exceeds
	ca_maxresponsesize_cached (and sa_cachethis or		ca_maxresponsesize_cached (and sa_cachethis or
	csa_cachethis is TRUE), then the server MUST return		csa_cachethis is TRUE), then the server <bcp14>MUST</bcp14> return
	NFS4ERR_REP_TOO_BIG_TO_CACHE. Even if		NFS4ERR_REP_TOO_BIG_TO_CACHE. Even if
	NFS4ERR_REP_TOO_BIG_TO_CACHE (or any other error for		NFS4ERR_REP_TOO_BIG_TO_CACHE (or any other error for
	that matter) is returned on an operation other than the		that matter) is returned on an operation other than the
	first operation (SEQUENCE or CB_SEQUENCE), then		first operation (SEQUENCE or CB_SEQUENCE), then
	the reply MUST be cached if sa_cachethis or		the reply <bcp14>MUST</bcp14> be cached if sa_cachethis or
	csa_cachethis is TRUE.		csa_cachethis is TRUE.
	For example, if a COMPOUND has eleven		For example, if a COMPOUND has eleven
	operations, including SEQUENCE, the fifth operation is		operations, including SEQUENCE, the fifth operation is
	a RENAME, and the tenth operation is a READ for one		a RENAME, and the tenth operation is a READ for one
	million bytes, the server may return		million bytes, the server may return
	NFS4ERR_REP_TOO_BIG_TO_CACHE on the tenth operation.		NFS4ERR_REP_TOO_BIG_TO_CACHE on the tenth operation.
	Since the server executed several operations, especially		Since the server executed several operations, especially
	the non-idempotent RENAME, the client's request to		the non-idempotent RENAME, the client's request to
	cache the reply needs to be honored in order for the		cache the reply needs to be honored in order for the
	correct operation of exactly once semantics. If the		correct operation of exactly once semantics. If the
	client retries the request, the server will have cached		client retries the request, the server will have cached
	a reply that contains results for ten of the eleven requested		a reply that contains results for ten of the eleven requested
	operations, with		operations, with
	the tenth operation having a status of NFS4ERR_REP_TOO_BIG_TO_CACHE.		the tenth operation having a status of NFS4ERR_REP_TOO_BIG_TO_CACHE.
	</t>		</t>
	<t>		<t>
	A client needs to take care that, when sending		A client needs to take care that, when sending
	operations that change the current filehandle (except for		operations that change the current filehandle (except for
	PUTFH, PUTPUBFH, PUTROOTFH, and RESTOREFH), it		PUTFH, PUTPUBFH, PUTROOTFH, and RESTOREFH), it
	does not exceed the maximum reply buffer before the GETFH		does not exceed the maximum reply buffer before the GETFH
	operation. Otherwise, the client will have to retry		operation. Otherwise, the client will have to retry
	the operation that changed the current filehandle, in order		the operation that changed the current filehandle, in order
	to obtain the desired filehandle.		to obtain the desired filehandle.
	For the OPEN operation (see <xref target="OP_OPEN" />),		For the OPEN operation (see <xref target="OP_OPEN" format="default"/>),
	retry is not always available as an option.		retry is not always available as an option.
	The following guidelines for the handling of		The following guidelines for the handling of
	filehandle-changing operations are advised:		filehandle-changing operations are advised:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Within the same COMPOUND procedure, a client		Within the same COMPOUND procedure, a client
	SHOULD send GETFH immediately after a current		<bcp14>SHOULD</bcp14> send GETFH immediately after a current
	filehandle-changing operation. A client		filehandle-changing operation. A client
	MUST send GETFH after a current filehandle-changing operation		<bcp14>MUST</bcp14> send GETFH after a current filehandle-changing operatio n
	that is also non-idempotent (e.g., the OPEN operation), unless		that is also non-idempotent (e.g., the OPEN operation), unless
	the operation is RESTOREFH. RESTOREFH is		the operation is RESTOREFH. RESTOREFH is
	an exception, because even though it is		an exception, because even though it is
	non-idempotent, the filehandle RESTOREFH		non-idempotent, the filehandle RESTOREFH
	produced originated from an operation that		produced originated from an operation that
	is either idempotent (e.g., PUTFH, LOOKUP),		is either idempotent (e.g., PUTFH, LOOKUP),
	or non-idempotent (e.g., OPEN, CREATE). If the		or non-idempotent (e.g., OPEN, CREATE). If the
	origin is non-idempotent, then because the client		origin is non-idempotent, then because the client
	MUST send GETFH after the origin operation, the		<bcp14>MUST</bcp14> send GETFH after the origin operation, the
	client can recover if RESTOREFH returns an error.		client can recover if RESTOREFH returns an error.
	</t>		</li>
	<t>		<li>
	A server MAY return NFS4ERR_REP_TOO_BIG or		A server <bcp14>MAY</bcp14> return NFS4ERR_REP_TOO_BIG or
	NFS4ERR_REP_TOO_BIG_TO_CACHE (if sa_cachethis is TRUE)		NFS4ERR_REP_TOO_BIG_TO_CACHE (if sa_cachethis is TRUE)
	on a filehandle-changing operation if the reply would		on a filehandle-changing operation if the reply would
	be too large on the next operation.		be too large on the next operation.
	</t>		</li>
	<t>		<li>
	A server SHOULD return NFS4ERR_REP_TOO_BIG or		A server <bcp14>SHOULD</bcp14> return NFS4ERR_REP_TOO_BIG or
	NFS4ERR_REP_TOO_BIG_TO_CACHE (if sa_cachethis is TRUE)		NFS4ERR_REP_TOO_BIG_TO_CACHE (if sa_cachethis is TRUE)
	on a filehandle-changing, non-idempotent operation if the reply would		on a filehandle-changing, non-idempotent operation if the reply would
	be too large on the next operation, especially if the operation		be too large on the next operation, especially if the operation
	is OPEN.		is OPEN.
	</t>		</li>
	<t>		<li>
	A server MAY return NFS4ERR_UNSAFE_COMPOUND to a non-idempotent		A server <bcp14>MAY</bcp14> return NFS4ERR_UNSAFE_COMPOUND to a non-idempot
			ent
	current filehandle-changing operation, if		current filehandle-changing operation, if
	it looks at the next operation (in the same COMPOUND procedure)		it looks at the next operation (in the same COMPOUND procedure)
	and finds it is		and finds it is
	not GETFH. The server SHOULD do this if it is unable to		not GETFH. The server <bcp14>SHOULD</bcp14> do this if it is unable to
	determine in advance whether the total response size		determine in advance whether the total response size
	would exceed ca_maxresponsesize_cached or ca_maxresponsesize.		would exceed ca_maxresponsesize_cached or ca_maxresponsesize.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section> <!-- COMPOUND and CB_COMPOUND Construction Issues -->		<section anchor="Persistence" numbered="true" toc="default">
	<section anchor="Persistence" title="Persistence">		<name>Persistence</name>
	<t>		<t>
	Since the reply cache is bounded, it is practical for		Since the reply cache is bounded, it is practical for
	the reply cache to persist across server restarts.		the reply cache to persist across server restarts.
	The replier MUST persist the following information		The replier <bcp14>MUST</bcp14> persist the following information
	if it agreed to persist the session (when the session		if it agreed to persist the session (when the session
	was created; see <xref target="OP_CREATE_SESSION" />):		was created; see <xref target="OP_CREATE_SESSION" format="default"/>):
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	The session ID.		The session ID.
	</t>		</li>
	<t>		<li>
	The slot table including the sequence ID and cached reply for		The slot table including the sequence ID and cached reply for
	each slot.		each slot.
	</t>		</li>
	</list>		</ul>
			<t>
	The above are sufficient for a replier to provide EOS semantics		The above are sufficient for a replier to provide EOS semantics
	for any requests that were sent and executed before the server		for any requests that were sent and executed before the server
	restarted.		restarted.
	If the replier is a client, then there is no need for		If the replier is a client, then there is no need for
	it to persist any more information, unless the client will		it to persist any more information, unless the client will
	be persisting all other state across client restart, in which case,		be persisting all other state across client restart, in which case,
	the server will never see any NFSv4.1-level protocol manifestation		the server will never see any NFSv4.1-level protocol manifestation
	of a client restart.		of a client restart.
	If the replier is a server, with just the		If the replier is a server, with just the
	slot table and session ID persisting,		slot table and session ID persisting,
	any requests the client retries after the server restart will		any requests the client retries after the server restart will
	return the results that are cached in the reply cache,		return the results that are cached in the reply cache,
	and any new requests (i.e., the sequence ID is one greater than the		and any new requests (i.e., the sequence ID is one greater than the
	slot's sequence ID) MUST be rejected with NFS4ERR_DEADSESSION		slot's sequence ID) <bcp14>MUST</bcp14> be rejected with NFS4ERR_DEADSESSION
	(returned by SEQUENCE). Such a session is considered dead.		(returned by SEQUENCE). Such a session is considered dead.
	A server MAY re-animate a session		A server <bcp14>MAY</bcp14> re-animate a session
	after a server restart so that the session will accept new		after a server restart so that the session will accept new
	requests as well as retries. To re-animate a session,		requests as well as retries. To re-animate a session,
	the server needs to persist additional information		the server needs to persist additional information
	through server restart:		through server restart:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	The client ID. This is a prerequisite to let the client		The client ID. This is a prerequisite to let the client
	create more sessions associated with the same client ID		create more sessions associated with the same client ID
	as the re-animated session.		as the re-animated session.
	</t>		</li>
	<t>		<li>
	The client ID's sequence ID that is used for creating		The client ID's sequence ID that is used for creating
	sessions (see Sections <xref target="OP_EXCHANGE_ID" format="counter" /> an		sessions (see Sections <xref target="OP_EXCHANGE_ID" format="counter"/> and
	d		<xref target="OP_CREATE_SESSION" format="counter"/>). This is a
	<xref target="OP_CREATE_SESSION" format="counter" />). This is a
	prerequisite to let the client create more sessions.		prerequisite to let the client create more sessions.
	</t>		</li>
	<t>		<li>
	The principal that created the client ID. This		The principal that created the client ID. This
	allows the server to authenticate the client when		allows the server to authenticate the client when
	it sends EXCHANGE_ID.		it sends EXCHANGE_ID.
	</t>		</li>
	<t>		<li>
	The SSV, if SP4_SSV state protection was		The SSV, if SP4_SSV state protection was
	specified when the client ID was created (see <xref		specified when the client ID was created (see <xref target="OP_EXCHANGE_ID"
	target="OP_EXCHANGE_ID" />). This lets the		format="default"/>). This lets the
	client create new sessions, and associate connections		client create new sessions, and associate connections
	with the new and existing sessions.		with the new and existing sessions.
	</t>		</li>
	<t>		<li>
	The properties of the client ID as defined in		The properties of the client ID as defined in
	<xref target="OP_EXCHANGE_ID" />.		<xref target="OP_EXCHANGE_ID" format="default"/>.
	</t>		</li>
			</ul>
	</list>		<t>
	</t>
	<t>
	A persistent reply cache places certain demands on the server.		A persistent reply cache places certain demands on the server.
	The execution of the sequence of operations (starting with SEQUENCE)		The execution of the sequence of operations (starting with SEQUENCE)
	and placement of its results in the persistent cache MUST be atomic. If		and placement of its results in the persistent cache <bcp14>MUST</bcp14> be atomic. If
	a client retries a sequence of operations that was previously		a client retries a sequence of operations that was previously
	executed on the server, the only acceptable outcomes are either		executed on the server, the only acceptable outcomes are either
	the original cached reply or an indication that the client ID		the original cached reply or an indication that the client ID
	or session has been lost (indicating a catastrophic loss		or session has been lost (indicating a catastrophic loss
	of the reply cache or a session that has been deleted because		of the reply cache or a session that has been deleted because
	the client failed to use the session for an extended period		the client failed to use the session for an extended period
	of time).		of time).
	</t>		</t>
	<t>		<t>
	A server could fail and restart in the middle of a		A server could fail and restart in the middle of a
	COMPOUND procedure that contains one or more non-idempotent		COMPOUND procedure that contains one or more non-idempotent
	or idempotent-but-modifying operations. This creates		or idempotent-but-modifying operations. This creates
	an even higher challenge for atomic execution and		an even higher challenge for atomic execution and
	placement of results in the reply cache. One way		placement of results in the reply cache. One way
	to view the problem is as a single transaction consisting of		to view the problem is as a single transaction consisting of
	each operation in the COMPOUND followed by storing		each operation in the COMPOUND followed by storing
	the result in persistent storage, then finally a transaction		the result in persistent storage, then finally a transaction
	commit. If there is a failure before the transaction		commit. If there is a failure before the transaction
	is committed, then the server rolls back the transaction.		is committed, then the server rolls back the transaction.
	If the server itself fails, then when it restarts, its		If the server itself fails, then when it restarts, its
	recovery logic could roll back the transaction		recovery logic could roll back the transaction
	before starting the NFSv4.1 server.		before starting the NFSv4.1 server.
	</t>		</t>
	<t>		<t>
	While the description of the		While the description of the
	implementation for atomic execution of the request		implementation for atomic execution of the request
	and caching of the reply		and caching of the reply
	is beyond the scope of this document, an example implementation		is beyond the scope of this document, an example implementation
	for NFSv2 <xref target="RFC1094"/> is described in <xref target="ha_nfs_ibm"		for NFSv2 <xref target="RFC1094" format="default"/> is described in <xref ta
	/>.		rget="ha_nfs_ibm" format="default"/>.
	</t>		</t>
	</section> <!-- Persistence -->		</section>
	</section> <!-- Exactly Once Semantics -->		</section>
	<section anchor="RDMA_Considerations" title="RDMA Considerations">		<section anchor="RDMA_Considerations" numbered="true" toc="default">
	<t>		<name>RDMA Considerations</name>
			<t>
	A complete discussion of the operation of RPC-based		A complete discussion of the operation of RPC-based
	protocols over RDMA transports is in <xref target="RFC8166" />. A		protocols over RDMA transports is in <xref target="RFC8166" format="default"/ >. A
	discussion of the operation of NFSv4, including NFSv4.1,		discussion of the operation of NFSv4, including NFSv4.1,
	over RDMA is in <xref target="RFC8267" />. Where RDMA is considered,		over RDMA is in <xref target="RFC8267" format="default"/>. Where RDMA is con sidered,
	this specification assumes the use of such a layering;		this specification assumes the use of such a layering;
	it addresses only the upper-layer issues relevant to		it addresses only the upper-layer issues relevant to
	making best use of RPC/RDMA.		making best use of RPC/RDMA.
	</t>		</t>
	<section anchor="RDMA_Connection_Resources" title="RDMA Connection Resources"		<section anchor="RDMA_Connection_Resources" numbered="true" toc="defau
	>		lt">
	<t>		<name>RDMA Connection Resources</name>
			<t>
	RDMA requires its consumers to register memory and post		RDMA requires its consumers to register memory and post
	buffers of a specific size and number for receive		buffers of a specific size and number for receive
	operations.		operations.
	</t>		</t>
	<t>		<t>
	Registration of memory can be a relatively high-overhead operation,		Registration of memory can be a relatively high-overhead operation,
	since it requires pinning of buffers, assignment of attributes		since it requires pinning of buffers, assignment of attributes
	(e.g., readable/writable), and initialization of hardware		(e.g., readable/writable), and initialization of hardware
	translation. Preregistration is desirable to reduce overhead.		translation. Preregistration is desirable to reduce overhead.
	These registrations are specific to hardware interfaces and even to		These registrations are specific to hardware interfaces and even to
	RDMA connection endpoints; therefore, negotiation of their limits is		RDMA connection endpoints; therefore, negotiation of their limits is
	desirable to manage resources effectively.		desirable to manage resources effectively.
	</t>		</t>
	<t>		<t>
	Following basic registration, these buffers must be posted by		Following basic registration, these buffers must be posted by
	the RPC layer to handle receives. These buffers remain in use by		the RPC layer to handle receives. These buffers remain in use by
	the RPC/NFSv4.1 implementation; the size and number of them must be		the RPC/NFSv4.1 implementation; the size and number of them must be
	known to the remote peer in order to avoid RDMA errors that would		known to the remote peer in order to avoid RDMA errors that would
	cause a fatal error on the RDMA connection.		cause a fatal error on the RDMA connection.
	</t>		</t>
	<t>		<t>
	NFSv4.1 manages slots as resources on a per-session		NFSv4.1 manages slots as resources on a per-session
	basis (see <xref target="Session" />), while RDMA		basis (see <xref target="Session" format="default"/>), while RDMA
	connections manage credits on a per-connection basis.		connections manage credits on a per-connection basis.
	This means that in order for a peer to send data over		This means that in order for a peer to send data over
	RDMA to a remote buffer, it has to have both an NFSv4.1		RDMA to a remote buffer, it has to have both an NFSv4.1
	slot and an RDMA credit. If multiple RDMA connections		slot and an RDMA credit. If multiple RDMA connections
	are associated with a session, then if the total number		are associated with a session, then if the total number
	of credits across all RDMA connections associated with		of credits across all RDMA connections associated with
	the session is X, and the number of slots in the session		the session is X, and the number of slots in the session
	is Y, then the maximum number of outstanding requests		is Y, then the maximum number of outstanding requests
	is the lesser of X and Y.		is the lesser of X and Y.
	</t>		</t>
	</section> <!-- RDMA Connection Resources -->		</section>
	<section anchor="Flow_Control" title="Flow Control">		<section anchor="Flow_Control" numbered="true" toc="default">
	<t>		<name>Flow Control</name>
			<t>
	Previous versions of NFS do not provide flow control;		Previous versions of NFS do not provide flow control;
	instead, they rely on the windowing provided by		instead, they rely on the windowing provided by
	transports like TCP to throttle requests. This does		transports like TCP to throttle requests. This does
	not work with RDMA, which provides no operation flow		not work with RDMA, which provides no operation flow
	control and will terminate a connection in error when		control and will terminate a connection in error when
	limits are exceeded.		limits are exceeded.
	Limits such as maximum number of requests		Limits such as maximum number of requests
	outstanding are therefore negotiated when a session		outstanding are therefore negotiated when a session
	is created (see the ca_maxrequests field in <xref		is created (see the ca_maxrequests field in <xref target="OP_CREATE_SESSION"
	target="OP_CREATE_SESSION" />). These limits then		format="default"/>). These limits then
	provide the maxima within which each connection associated		provide the maxima within which each connection associated
	with the session's channel(s) must remain.		with the session's channel(s) must remain.
	RDMA connections are managed within these limits as		RDMA connections are managed within these limits as
	described in Section 3.3 of <xref target="RFC8166" />; if there are multiple		described in <xref target="RFC8166" sectionFormat="of" section="3.3"/>; if t here are multiple
	RDMA connections, then the maximum number of requests		RDMA connections, then the maximum number of requests
	for a channel will be divided among the RDMA		for a channel will be divided among the RDMA
	connections. Put a different way, the onus is on the		connections. Put a different way, the onus is on the
	replier to ensure that the total number of RDMA credits		replier to ensure that the total number of RDMA credits
	across all connections associated with the replier's		across all connections associated with the replier's
	channel does exceed the channel's maximum number of		channel does exceed the channel's maximum number of
	outstanding requests.		outstanding requests.
	</t>		</t>
	<t>		<t>
	The limits may also be modified		The limits may also be modified
	dynamically at the replier's choosing by manipulating		dynamically at the replier's choosing by manipulating
	certain parameters present in each NFSv4.1 reply. In		certain parameters present in each NFSv4.1 reply. In
	addition, the CB_RECALL_SLOT callback operation (see		addition, the CB_RECALL_SLOT callback operation (see
	<xref target="OP_CB_RECALL_SLOT" />) can be sent by		<xref target="OP_CB_RECALL_SLOT" format="default"/>) can be sent by
	a server to a client to return RDMA credits to the		a server to a client to return RDMA credits to the
	server, thereby lowering the maximum number of requests		server, thereby lowering the maximum number of requests
	a client can have outstanding to the server.		a client can have outstanding to the server.
	</t>		</t>
	</section> <!-- Flow Control -->		</section>
	<section anchor="Padding" title="Padding">		<section anchor="Padding" numbered="true" toc="default">
	<t>		<name>Padding</name>
			<t>
	Header padding is requested by each peer at session initiation		Header padding is requested by each peer at session initiation
	(see the ca_headerpadsize argument to CREATE_SESSION in		(see the ca_headerpadsize argument to CREATE_SESSION in
	<xref target="OP_CREATE_SESSION" />), and		<xref target="OP_CREATE_SESSION" format="default"/>), and
	subsequently used by the RPC RDMA layer, as described in <xref target="R		subsequently used by the RPC RDMA layer, as described in <xref target="R
	FC8166" />.		FC8166" format="default"/>.
	Zero padding is permitted.		Zero padding is permitted.
	</t>		</t>
	<t>		<t>
	Padding leverages the useful property		Padding leverages the useful property
	that RDMA preserve alignment of data, even when they are		that RDMA preserve alignment of data, even when they are
	placed into anonymous (untagged) buffers. If requested, client		placed into anonymous (untagged) buffers. If requested, client
	inline writes will insert appropriate pad bytes within the request		inline writes will insert appropriate pad bytes within the request
	header to align the data payload on the specified boundary. The		header to align the data payload on the specified boundary. The
	client is encouraged to add sufficient padding (up to the		client is encouraged to add sufficient padding (up to the
	negotiated size) so that		negotiated size) so that
	the "data" field of the WRITE operation		the "data" field of the WRITE operation
	is aligned.		is aligned.
	Most servers can make good use of such padding,		Most servers can make good use of such padding,
	which allows them to chain receive buffers in such a way that any		which allows them to chain receive buffers in such a way that any
	data carried by client requests will be placed into appropriate		data carried by client requests will be placed into appropriate
	buffers at the server, ready for file system processing. The		buffers at the server, ready for file system processing. The
	receiver's RPC layer encounters no overhead from skipping over pad		receiver's RPC layer encounters no overhead from skipping over pad
	bytes, and the RDMA layer's high performance makes the insertion		bytes, and the RDMA layer's high performance makes the insertion
	and transmission of padding on the sender a significant		and transmission of padding on the sender a significant
	optimization. In this way, the need for servers to perform RDMA		optimization. In this way, the need for servers to perform RDMA
	Read to satisfy all but the largest client writes is obviated. An		Read to satisfy all but the largest client writes is obviated. An
	added benefit is the reduction of message round trips on the network		added benefit is the reduction of message round trips on the network
	-- a potentially good trade, where latency is present.		-- a potentially good trade, where latency is present.
	</t>		</t>
	<t>		<t>
	The value to choose for padding is subject to a number of criteria.		The value to choose for padding is subject to a number of criteria.
	A primary source of variable-length data in the RPC header is the		A primary source of variable-length data in the RPC header is the
	authentication information, the form of which is client-determined,		authentication information, the form of which is client-determined,
	possibly in response to server specification. The contents of		possibly in response to server specification. The contents of
	COMPOUNDs, sizes of strings such as those passed to RENAME, etc. all		COMPOUNDs, sizes of strings such as those passed to RENAME, etc. all
	go into the determination of a maximal NFSv4.1 request size and		go into the determination of a maximal NFSv4.1 request size and
	therefore minimal buffer size. The client must select its offered		therefore minimal buffer size. The client must select its offered
	value carefully, so as to avoid overburdening the server, and vice		value carefully, so as to avoid overburdening the server, and vice
	versa. The benefit of an appropriate padding value is higher		versa. The benefit of an appropriate padding value is higher
	performance.		performance.
	</t>		</t>
	<figure>		<artwork name="" type="" align="left" alt=""><![CDATA[
	<artwork>
	Sender gather:		Sender gather:
	|RPC Request|Pad bytes|Length| -> |User data...|		|RPC Request|Pad bytes|Length| -> |User data...|
	\------+----------------------/ \		\------+----------------------/ \
	\ \		\ \
	\ Receiver scatter: \-----------+- ...		\ Receiver scatter: \-----------+- ...
	/-----+----------------\ \ \		/-----+----------------\ \ \
	|RPC Request|Pad|Length| -> |FS buffer|->|FS buffer|->...		|RPC Request|Pad|Length| -> |FS buffer|->|FS buffer|->...
	</artwork>		]]></artwork>
	</figure>		<t>
	<t>
	In the above case, the server may recycle unused buffers to the		In the above case, the server may recycle unused buffers to the
	next posted receive if unused by the actual received request, or		next posted receive if unused by the actual received request, or
	may pass the now-complete buffers by reference for normal write		may pass the now-complete buffers by reference for normal write
	processing. For a server that can make use of it, this removes		processing. For a server that can make use of it, this removes
	any need for data copies of incoming data, without resorting to		any need for data copies of incoming data, without resorting to
	complicated end-to-end buffer advertisement and management. This		complicated end-to-end buffer advertisement and management. This
	includes most kernel-based and integrated server designs, among		includes most kernel-based and integrated server designs, among
	many others. The client may perform similar optimizations, if		many others. The client may perform similar optimizations, if
	desired.		desired.
	</t>		</t>
	</section> <!-- Padding -->		</section>
	<section anchor="dual" title="Dual RDMA and Non-RDMA Transports">		<section anchor="dual" numbered="true" toc="default">
	<t>		<name>Dual RDMA and Non-RDMA Transports</name>
	Some RDMA transports (e.g., <xref target="RDMAP">RFC 5040</xref>)		<t>
			Some RDMA transports (e.g., RFC 5040 <xref target="RFC5040" format="default"
			/>)
	permit a "streaming" (non-RDMA) phase,		permit a "streaming" (non-RDMA) phase,
	where ordinary traffic might flow before "stepping up"		where ordinary traffic might flow before "stepping up"
	to RDMA mode, commencing RDMA traffic. Some RDMA		to RDMA mode, commencing RDMA traffic. Some RDMA
	transports start connections always in RDMA mode.		transports start connections always in RDMA mode.
	NFSv4.1 allows, but does not assume, a streaming phase		NFSv4.1 allows, but does not assume, a streaming phase
	before RDMA mode. When a connection		before RDMA mode. When a connection
	is associated with a session, the client and server negotiate whether the		is associated with a session, the client and server negotiate whether the
	connection is used in RDMA or non-RDMA mode (see Sections		connection is used in RDMA or non-RDMA mode (see Sections
	<xref target="OP_CREATE_SESSION" format="counter" /> and		<xref target="OP_CREATE_SESSION" format="counter"/> and
	<xref target="OP_BIND_CONN_TO_SESSION" format="counter" />).		<xref target="OP_BIND_CONN_TO_SESSION" format="counter"/>).
	</t>		</t>
	</section> <!-- RDMA Transports -->		</section>
	</section> <!-- RDMA Considerations -->		</section>
	<section anchor="Sessions_Security" title="Session Security">		<section anchor="Sessions_Security" numbered="true" toc="default">
	<section anchor="Session_Callback_Security" title="Session Callback Security"		<name>Session Security</name>
	>		<section anchor="Session_Callback_Security" numbered="true" toc="defau
	<t>		lt">
			<name>Session Callback Security</name>
			<t>
	Via session/connection association, NFSv4.1 improves security over		Via session/connection association, NFSv4.1 improves security over
	that provided by NFSv4.0 for the backchannel. The		that provided by NFSv4.0 for the backchannel. The
	connection is client-initiated (see		connection is client-initiated (see
	<xref target="OP_BIND_CONN_TO_SESSION" />) and subject to the same		<xref target="OP_BIND_CONN_TO_SESSION" format="default"/>) and subject to th e same
	firewall and routing checks as the fore channel.		firewall and routing checks as the fore channel.
	At the client's option (see <xref target="OP_EXCHANGE_ID" />),		At the client's option (see <xref target="OP_EXCHANGE_ID" format="default"/> ),
	connection association is fully authenticated before being		connection association is fully authenticated before being
	activated (see <xref target="OP_BIND_CONN_TO_SESSION" />).		activated (see <xref target="OP_BIND_CONN_TO_SESSION" format="default"/>).
	Traffic from the server over the		Traffic from the server over the
	backchannel is authenticated exactly as the client specifies		backchannel is authenticated exactly as the client specifies
	(see <xref target="Backchannel_RPC_Security" />).		(see <xref target="Backchannel_RPC_Security" format="default"/>).
	</t>		</t>
	</section> <!-- Session Callback Security -->		</section>
	<section anchor="Backchannel_RPC_Security" title="Backchannel RPC Security">		<section anchor="Backchannel_RPC_Security" numbered="true" toc="default">
	<t>		<name>Backchannel RPC Security</name>
			<t>
	When the NFSv4.1 client establishes the backchannel, it		When the NFSv4.1 client establishes the backchannel, it
	informs the server of the security flavors and principals		informs the server of the security flavors and principals
	to use when sending requests. If the security flavor is		to use when sending requests. If the security flavor is
	RPCSEC_GSS, the client expresses the principal in the form		RPCSEC_GSS, the client expresses the principal in the form
	of an established RPCSEC_GSS context. The server is free		of an established RPCSEC_GSS context. The server is free
	to use any of the flavor/principal combinations the client		to use any of the flavor/principal combinations the client
	offers, but it MUST NOT use unoffered combinations.		offers, but it <bcp14>MUST NOT</bcp14> use unoffered combinations.
	This way, the client need not provide a target		This way, the client need not provide a target
	GSS principal for the backchannel as it did with		GSS principal for the backchannel as it did with
	NFSv4.0, nor does the server have to implement an		NFSv4.0, nor does the server have to implement an
	RPCSEC_GSS initiator as it did with NFSv4.0 <xref		RPCSEC_GSS initiator as it did with NFSv4.0 <xref target="RFC3530" format="
	target="RFC3530" />.		default"/>.
	</t>		</t>
	<t>		<t>
	The CREATE_SESSION (<xref target="OP_CREATE_SESSION" />)		The CREATE_SESSION (<xref target="OP_CREATE_SESSION" format="default"/>)
	and BACKCHANNEL_CTL (<xref target="OP_BACKCHANNEL_CTL" />)		and BACKCHANNEL_CTL (<xref target="OP_BACKCHANNEL_CTL" format="default"/>)
	operations allow the client to specify flavor/principal combinations.		operations allow the client to specify flavor/principal combinations.
	</t>		</t>
	<t>		<t>
	Also note that the SP4_SSV state protection mode		Also note that the SP4_SSV state protection mode
	(see Sections <xref target="OP_EXCHANGE_ID" format="counter" /> and <xref		(see Sections <xref target="OP_EXCHANGE_ID" format="counter"/> and <xref ta
	target="protect_state_change" format="counter" />) has the side		rget="protect_state_change" format="counter"/>) has the side
	benefit of providing SSV-derived RPCSEC_GSS contexts (<xref target="ssv_mec		benefit of providing SSV-derived RPCSEC_GSS contexts (<xref target="ssv_mec
	h" />).		h" format="default"/>).
	</t>		</t>
	</section> <!-- Backchannel RPC Security -->		</section>
	<section anchor="protect_state_change"		<section anchor="protect_state_change" numbered="true" toc="default">
	title="Protection from Unauthorized State Changes">		<name>Protection from Unauthorized State Changes</name>
	<t>		<t>
	As described to this point in the specification, the state model		As described to this point in the specification, the state model
	of NFSv4.1 is vulnerable to an attacker that		of NFSv4.1 is vulnerable to an attacker that
	sends a SEQUENCE operation with a forged session ID and with a slot ID that		sends a SEQUENCE operation with a forged session ID and with a slot ID that
	it expects the legitimate client to use next. When the legitimate client		it expects the legitimate client to use next. When the legitimate client
	uses the slot ID with the same sequence number, the server		uses the slot ID with the same sequence number, the server
	returns the attacker's result from the reply cache, which		returns the attacker's result from the reply cache, which
	disrupts the legitimate client and thus denies service to it.		disrupts the legitimate client and thus denies service to it.
	Similarly, an attacker could send a CREATE_SESSION with a forged		Similarly, an attacker could send a CREATE_SESSION with a forged
	client ID to create a new session associated with the client ID.		client ID to create a new session associated with the client ID.
	The attacker could send requests using the new session that		The attacker could send requests using the new session that
	change locking state, such as LOCKU operations to release locks		change locking state, such as LOCKU operations to release locks
	the legitimate client has acquired. Setting a security		the legitimate client has acquired. Setting a security
	policy on the file that requires RPCSEC_GSS credentials when		policy on the file that requires RPCSEC_GSS credentials when
	manipulating the file's state is one potential work around,		manipulating the file's state is one potential work around,
	but has the disadvantage of preventing a legitimate client from		but has the disadvantage of preventing a legitimate client from
	releasing state when RPCSEC_GSS is required to do so, but		releasing state when RPCSEC_GSS is required to do so, but
	a GSS context cannot be obtained (possibly because the user		a GSS context cannot be obtained (possibly because the user
	has logged off the client).		has logged off the client).
	</t>		</t>
	<t>		<t>
	NFSv4.1 provides three options to a client for state protection,		NFSv4.1 provides three options to a client for state protection,
	which are specified when a client creates		which are specified when a client creates
	a client ID via EXCHANGE_ID (<xref target="OP_EXCHANGE_ID" />).		a client ID via EXCHANGE_ID (<xref target="OP_EXCHANGE_ID" format="default"
	</t>		/>).
	<t>		</t>
			<t>
	The first (SP4_NONE) is to simply waive state protection.		The first (SP4_NONE) is to simply waive state protection.
	</t>		</t>
	<t>		<t>
	The other two options (SP4_MACH_CRED and SP4_SSV)		The other two options (SP4_MACH_CRED and SP4_SSV)
	share several traits:		share several traits:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	An RPCSEC_GSS-based credential is used to authenticate		An RPCSEC_GSS-based credential is used to authenticate
	client ID and session maintenance operations,		client ID and session maintenance operations,
	including creating and destroying a session,		including creating and destroying a session,
	associating a connection with the session, and		associating a connection with the session, and
	destroying the client ID.		destroying the client ID.
	</t>		</li>
	<t>		<li>
	Because RPCSEC_GSS is used to authenticate		Because RPCSEC_GSS is used to authenticate
	client ID and session maintenance, the attacker cannot		client ID and session maintenance, the attacker cannot
	associate a rogue connection with a legitimate session, or		associate a rogue connection with a legitimate session, or
	associate a rogue session with a legitimate client ID in		associate a rogue session with a legitimate client ID in
	order to maliciously alter the client ID's lock state		order to maliciously alter the client ID's lock state
	via CLOSE, LOCKU, DELEGRETURN, LAYOUTRETURN, etc.		via CLOSE, LOCKU, DELEGRETURN, LAYOUTRETURN, etc.
	</t>		</li>
	<t>		<li>
	In cases where the server's security policies on a		In cases where the server's security policies on a
	portion of its namespace require RPCSEC_GSS authentication,		portion of its namespace require RPCSEC_GSS authentication,
	a client may have to use an RPCSEC_GSS credential		a client may have to use an RPCSEC_GSS credential
	to remove per-file state (e.g., LOCKU, CLOSE, etc.).		to remove per-file state (e.g., LOCKU, CLOSE, etc.).
	The server may require that the principal that removes		The server may require that the principal that removes
	the state match certain criteria (e.g.,		the state match certain criteria (e.g.,
	the principal might have to be the same as the one		the principal might have to be the same as the one
	that acquired the state). However, the client might		that acquired the state). However, the client might
	not have an RPCSEC_GSS context for such a principal,		not have an RPCSEC_GSS context for such a principal,
	and might not be able to create such a context (perhaps		and might not be able to create such a context (perhaps
	because the user has logged off). When the client		because the user has logged off). When the client
	establishes SP4_MACH_CRED or SP4_SSV protection,		establishes SP4_MACH_CRED or SP4_SSV protection,
	it can specify a list of operations that the server MUST		it can specify a list of operations that the server <bcp14>MUST</bcp14>
	allow using the machine credential (if SP4_MACH_CRED		allow using the machine credential (if SP4_MACH_CRED
	is used) or the SSV credential (if SP4_SSV is used).		is used) or the SSV credential (if SP4_SSV is used).
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The SP4_MACH_CRED state protection option uses a machine		The SP4_MACH_CRED state protection option uses a machine
	credential where the principal that		credential where the principal that
	creates the client ID MUST also be the principal		creates the client ID <bcp14>MUST</bcp14> also be the principal
	that performs client ID and session maintenance		that performs client ID and session maintenance
	operations.		operations.
	The security of the machine credential state protection approach		The security of the machine credential state protection approach
	depends entirely on safeguarding the per-machine credential.		depends entirely on safeguarding the per-machine credential.
	Assuming a proper safeguard using the per-machine credential		Assuming a proper safeguard using the per-machine credential
	for operations like CREATE_SESSION, BIND_CONN_TO_SESSION,		for operations like CREATE_SESSION, BIND_CONN_TO_SESSION,
	DESTROY_SESSION, and DESTROY_CLIENTID will prevent an attacker		DESTROY_SESSION, and DESTROY_CLIENTID will prevent an attacker
	from associating a rogue connection with a session, or		from associating a rogue connection with a session, or
	associating a rogue session with a client ID.		associating a rogue session with a client ID.
	</t>		</t>
	<t>		<t>
	There are at least three scenarios for the SP4_MACH_CRED		There are at least three scenarios for the SP4_MACH_CRED
	option:		option:
	<list style="numbers">		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	The system administrator configures a unique,		The system administrator configures a unique,
	permanent per-machine credential for one of the		permanent per-machine credential for one of the
	mandated GSS mechanisms (e.g., if Kerberos		mandated GSS mechanisms (e.g., if Kerberos
	V5 is used, a "keytab" containing a principal derived from a		V5 is used, a "keytab" containing a principal derived from a
	client host name could be used).		client host name could be used).
	</t>		</li>
	<t>		<li>
	The client is used by a single user, and so the		The client is used by a single user, and so the
	client ID and its sessions are used by just that		client ID and its sessions are used by just that
	user. If the user's credential expires, then session		user. If the user's credential expires, then session
	and client ID maintenance cannot occur, but since		and client ID maintenance cannot occur, but since
	the client has a single user, only that user is		the client has a single user, only that user is
	inconvenienced.		inconvenienced.
	</t>		</li>
	<t>		<li>
	The physical client has multiple users, but the		The physical client has multiple users, but the
	client implementation has a unique client ID for		client implementation has a unique client ID for
	each user. This is effectively the same as the		each user. This is effectively the same as the
	second scenario, but a disadvantage is that each		second scenario, but a disadvantage is that each
	user needs to be allocated at least one session each,		user needs to be allocated at least one session each,
	so the approach suffers from lack of economy.		so the approach suffers from lack of economy.
	</t>		</li>
			</ol>
	</list>		<t>
	</t>		The SP4_SSV protection option uses the SSV (<xref target="intro_definitions
	<t>		" format="default"/>), via RPCSEC_GSS and the SSV GSS
	The SP4_SSV protection option uses the SSV (<xref		mechanism (<xref target="ssv_mech" format="default"/>), to protect state fr
	target="intro_definitions"/>), via RPCSEC_GSS and the SSV GSS		om attack.
	mechanism (<xref target="ssv_mech" />), to protect state from attack.
	The SP4_SSV protection option is intended for the situation		The SP4_SSV protection option is intended for the situation
	comprised of a client that has multiple active users and a system		comprised of a client that has multiple active users and a system
	administrator who wants to avoid the burden of installing a permanent		administrator who wants to avoid the burden of installing a permanent
	machine credential on each client. The SSV is		machine credential on each client. The SSV is
	established and updated on the server via SET_SSV (see <xref		established and updated on the server via SET_SSV (see <xref target="OP_SET
	target="OP_SET_SSV" />). To prevent eavesdropping,		_SSV" format="default"/>). To prevent eavesdropping,
	a client SHOULD send SET_SSV via RPCSEC_GSS with		a client <bcp14>SHOULD</bcp14> send SET_SSV via RPCSEC_GSS with
	the privacy service. Several aspects of the SSV		the privacy service. Several aspects of the SSV
	make it intractable for an attacker to guess the SSV,		make it intractable for an attacker to guess the SSV,
	and thus associate rogue connections with a session,		and thus associate rogue connections with a session,
	and rogue sessions with a client ID:		and rogue sessions with a client ID:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The arguments to and results of SET_SSV include digests of the old and		The arguments to and results of SET_SSV include digests of the old and
	new SSV, respectively.		new SSV, respectively.
	</t>		</li>
	<t>		<li>
	Because the initial value of the SSV is zero,		Because the initial value of the SSV is zero,
	therefore known, the client that opts for SP4_SSV		therefore known, the client that opts for SP4_SSV
	protection and opts to apply SP4_SSV protection to		protection and opts to apply SP4_SSV protection to
	BIND_CONN_TO_SESSION and CREATE_SESSION MUST send		BIND_CONN_TO_SESSION and CREATE_SESSION <bcp14>MUST</bcp14> send
	at least one SET_SSV operation before the first		at least one SET_SSV operation before the first
	BIND_CONN_TO_SESSION operation or before the second		BIND_CONN_TO_SESSION operation or before the second
	CREATE_SESSION operation on a client ID. If it does		CREATE_SESSION operation on a client ID. If it does
	not, the SSV mechanism will not generate tokens		not, the SSV mechanism will not generate tokens
	(<xref target="ssv_mech" />).		(<xref target="ssv_mech" format="default"/>).
	A client SHOULD send SET_SSV as soon as a session		A client <bcp14>SHOULD</bcp14> send SET_SSV as soon as a session
	is created.		is created.
	</t>		</li>
	<t>		<li>
	A SET_SSV request does not replace the SSV with the argument to		A SET_SSV request does not replace the SSV with the argument to
	SET_SSV. Instead, the current SSV on the server is logically		SET_SSV. Instead, the current SSV on the server is logically
	exclusive ORed (XORed) with the argument to SET_SSV.		exclusive ORed (XORed) with the argument to SET_SSV.
	Each time a new principal uses a client ID for the first		Each time a new principal uses a client ID for the first
	time, the client		time, the client
	SHOULD send a SET_SSV with that principal's RPCSEC_GSS		<bcp14>SHOULD</bcp14> send a SET_SSV with that principal's RPCSEC_GSS
	credentials, with RPCSEC_GSS service set to RPC_GSS_SVC_PRIVACY.		credentials, with RPCSEC_GSS service set to RPC_GSS_SVC_PRIVACY.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Here are the types of attacks that can be attempted by an attacker named		Here are the types of attacks that can be attempted by an attacker named
	Eve on a victim named Bob, and how SP4_SSV protection foils		Eve on a victim named Bob, and how SP4_SSV protection foils
	each attack:		each attack:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	Suppose Eve is the first user to log into a		Suppose Eve is the first user to log into a
	legitimate client. Eve's use of an NFSv4.1		legitimate client. Eve's use of an NFSv4.1
	file system will cause the legitimate client to		file system will cause the legitimate client to
	create a client ID		create a client ID
	with SP4_SSV protection, specifying that the BIND_CONN_TO_SESSION		with SP4_SSV protection, specifying that the BIND_CONN_TO_SESSION
	operation MUST use the SSV credential. Eve's use of		operation <bcp14>MUST</bcp14> use the SSV credential. Eve's use of
	the file system also causes an SSV to be created. The		the file system also causes an SSV to be created. The
	SET_SSV operation that creates the SSV will be protected by		SET_SSV operation that creates the SSV will be protected by
	the RPCSEC_GSS context created by the legitimate		the RPCSEC_GSS context created by the legitimate
	client, which uses Eve's GSS principal and		client, which uses Eve's GSS principal and
	credentials. Eve can eavesdrop on the network while		credentials. Eve can eavesdrop on the network while
	her RPCSEC_GSS context is created and the SET_SSV		her RPCSEC_GSS context is created and the SET_SSV
	using her context is sent. Even if the legitimate		using her context is sent. Even if the legitimate
	client sends the SET_SSV with RPC_GSS_SVC_PRIVACY,		client sends the SET_SSV with RPC_GSS_SVC_PRIVACY,
	because Eve knows her own credentials, she can		because Eve knows her own credentials, she can
	decrypt the SSV. Eve can compute an RPCSEC_GSS		decrypt the SSV. Eve can compute an RPCSEC_GSS
	credential that BIND_CONN_TO_SESSION will accept,		credential that BIND_CONN_TO_SESSION will accept,
	and so associate a new connection with the		and so associate a new connection with the
	legitimate session. Eve can change the slot ID and		legitimate session. Eve can change the slot ID and
	sequence state of a legitimate session, and/or the		sequence state of a legitimate session, and/or the
	SSV state, in such a way that when Bob accesses		SSV state, in such a way that when Bob accesses
	the server via the same legitimate client, the		the server via the same legitimate client, the
	legitimate client will be unable to use the session.		legitimate client will be unable to use the session.
	<vspace blankLines='1' />		</t>
			<t>
	The client's only recourse is to create a new client		The client's only recourse is to create a new client
	ID for Bob to use, and establish a new SSV for the		ID for Bob to use, and establish a new SSV for the
	client ID. The client will be unable to delete		client ID. The client will be unable to delete
	the old client ID, and will let the lease on the old		the old client ID, and will let the lease on the old
	client ID expire.		client ID expire.
	<vspace blankLines='1' />		</t>
			<t>
	Once the legitimate client establishes an SSV over		Once the legitimate client establishes an SSV over
	the new session using Bob's RPCSEC_GSS context,		the new session using Bob's RPCSEC_GSS context,
	Eve can use the new session via the legitimate		Eve can use the new session via the legitimate
	client, but she cannot disrupt Bob. Moreover,		client, but she cannot disrupt Bob. Moreover,
	because the client SHOULD have modified the SSV		because the client <bcp14>SHOULD</bcp14> have modified the SSV
	due to Eve using the new session, Bob cannot get		due to Eve using the new session, Bob cannot get
	revenge on Eve by associating a rogue connection		revenge on Eve by associating a rogue connection
	with the session.		with the session.
	<vspace blankLines='1' />		</t>
			<t>
	The question is how did the legitimate client detect		The question is how did the legitimate client detect
	that Eve has hijacked the old session? When the		that Eve has hijacked the old session? When the
	client detects that a new principal, Bob, wants to		client detects that a new principal, Bob, wants to
	use the session, it SHOULD have sent a SET_SSV,		use the session, it <bcp14>SHOULD</bcp14> have sent a SET_SSV,
	which leads to the following sub-scenarios:		which leads to the following sub-scenarios:
	<vspace blankLines='1' />		</t>
			<ul spacing="normal">
	<list style="symbols">		<li>
	<t>		<t>
	Let us suppose that from the rogue connection, Eve		Let us suppose that from the rogue connection, Eve
	sent a SET_SSV with the same slot ID and sequence ID that		sent a SET_SSV with the same slot ID and sequence ID that
	the legitimate client later uses. The server will		the legitimate client later uses. The server will
	assume the SET_SSV sent with Bob's credentials is a retry,		assume the SET_SSV sent with Bob's credentials is a retry,
	and return to the legitimate		and return to the legitimate
	client the reply it sent Eve. However, unless Eve can		client the reply it sent Eve. However, unless Eve can
	correctly guess the SSV the legitimate client will use,		correctly guess the SSV the legitimate client will use,
	the digest verification checks in the SET_SSV response		the digest verification checks in the SET_SSV response
	will fail. That is an indication to the client that the		will fail. That is an indication to the client that the
	session has apparently been hijacked.		session has apparently been hijacked.
	<vspace blankLines='1' />		</t>
	</t>		</li>
	<t>		<li>
			<t>
	Alternatively, Eve sent a SET_SSV with a different slot ID than		Alternatively, Eve sent a SET_SSV with a different slot ID than
	the legitimate client uses for its SET_SSV. Then the digest		the legitimate client uses for its SET_SSV. Then the digest
	verification of the SET_SSV sent with Bob's credentials fails		verification of the SET_SSV sent with Bob's credentials fails
	on the server, and the error returned to the client makes it		on the server, and the error returned to the client makes it
	apparent that the session has been hijacked.		apparent that the session has been hijacked.
	<vspace blankLines='1' />		</t>
	</t>		</li>
	<t>		<li>
			<t>
	Alternatively, Eve sent an operation other than SET_SSV,		Alternatively, Eve sent an operation other than SET_SSV,
	but with the same slot ID and sequence that the legitimate client		but with the same slot ID and sequence that the legitimate client
	uses for its SET_SSV. The server returns to the legitimate		uses for its SET_SSV. The server returns to the legitimate
	client the response it sent Eve. The client sees that the		client the response it sent Eve. The client sees that the
	response is not at all what it expects. The client		response is not at all what it expects. The client
	assumes either session hijacking or a server bug, and either way		assumes either session hijacking or a server bug, and either way
	destroys the old session.		destroys the old session.
	<vspace blankLines='1' />		</t>
	</t>		</li>
	</list>		</ul>
	</t>		</li>
	<t>		<li>
			<t>
	Eve associates a rogue connection with the session		Eve associates a rogue connection with the session
	as above, and then destroys the session. Again, Bob		as above, and then destroys the session. Again, Bob
	goes to use the server from the legitimate client,		goes to use the server from the legitimate client,
	which sends a SET_SSV using Bob's credentials. The client receives an err or		which sends a SET_SSV using Bob's credentials. The client receives an err or
	that indicates that the session does not exist. When		that indicates that the session does not exist. When
	the client tries to create a new session, this		the client tries to create a new session, this
	will fail because the SSV it has does not match that which the		will fail because the SSV it has does not match that which the
	server has, and now the client knows the session		server has, and now the client knows the session
	was hijacked. The legitimate client establishes a		was hijacked. The legitimate client establishes a
	new client ID.		new client ID.
	<vspace blankLines='1' />		</t>
			</li>
	</t>		<li>
	<t>		<t>
	If Eve creates a connection before the legitimate		If Eve creates a connection before the legitimate
	client establishes an SSV, because the initial		client establishes an SSV, because the initial
	value of the SSV is zero and therefore known,		value of the SSV is zero and therefore known,
	Eve can send a SET_SSV that will pass the digest		Eve can send a SET_SSV that will pass the digest
	verification check. However, because the new		verification check. However, because the new
	connection has not been associated with the session,		connection has not been associated with the session,
	the SET_SSV is rejected for that reason.		the SET_SSV is rejected for that reason.
	<vspace blankLines='1' />		</t>
			</li>
	</t>		</ul>
	</list>		<t>
	In summary, an attacker's disruption of state when		In summary, an attacker's disruption of state when
	SP4_SSV protection is in use is limited to the		SP4_SSV protection is in use is limited to the
	formative period of a client ID, its first session,		formative period of a client ID, its first session,
	and the establishment of the SSV. Once a non-malicious		and the establishment of the SSV. Once a non-malicious
	user uses the client ID, the client quickly detects		user uses the client ID, the client quickly detects
	any hijack and rectifies the situation. Once a		any hijack and rectifies the situation. Once a
	non-malicious user successfully modifies the SSV,		non-malicious user successfully modifies the SSV,
	the attacker cannot use NFSv4.1 operations to disrupt		the attacker cannot use NFSv4.1 operations to disrupt
	the non-malicious user.		the non-malicious user.
	</t>		</t>
			<t>
	<t>
	Note that neither the SP4_MACH_CRED nor		Note that neither the SP4_MACH_CRED nor
	SP4_SSV protection approaches prevent hijacking		SP4_SSV protection approaches prevent hijacking
	of a transport connection that has previously been		of a transport connection that has previously been
	associated with a session. If the goal of a counter-threat		associated with a session. If the goal of a counter-threat
	strategy is to prevent connection hijacking, the use of IPsec is RECOMMENDE		strategy is to prevent connection hijacking, the use of IPsec is <bcp14>REC
	D.		OMMENDED</bcp14>.
	</t>		</t>
			<t>
	<t>
	If a connection hijack occurs, the hijacker could in		If a connection hijack occurs, the hijacker could in
	theory change locking state and negatively impact the		theory change locking state and negatively impact the
	service to legitimate clients. However, if the server		service to legitimate clients. However, if the server
	is configured to require the use of RPCSEC_GSS with		is configured to require the use of RPCSEC_GSS with
	integrity or privacy on the affected file objects, and		integrity or privacy on the affected file objects, and
	if EXCHGID4_FLAG_BIND_PRINC_STATEID capability (<xref		if EXCHGID4_FLAG_BIND_PRINC_STATEID capability (<xref target="OP_EXCHANGE_I
	target="OP_EXCHANGE_ID"/>) is in force, this will		D" format="default"/>) is in force, this will
	thwart unauthorized attempts to change locking state.		thwart unauthorized attempts to change locking state.
	</t>		</t>
			</section>
	</section> <!-- Protection from Unauthorized State Changes -->		</section>
	</section> <!-- Sessions Security -->		<section anchor="ssv_mech" numbered="true" toc="default">
	<section title="The Secret State Verifier (SSV) GSS Mechanism" anchor="ssv_mec		<name>The Secret State Verifier (SSV) GSS Mechanism</name>
	h">		<t>
	<t>
	The SSV provides the secret key for a GSS mechanism internal to NFSv4.1		The SSV provides the secret key for a GSS mechanism internal to NFSv4.1
	that NFSv4.1 uses for state protection. Contexts for this		that NFSv4.1 uses for state protection. Contexts for this
	mechanism are not established via the RPCSEC_GSS		mechanism are not established via the RPCSEC_GSS
	protocol. Instead, the contexts are automatically		protocol. Instead, the contexts are automatically
	created when EXCHANGE_ID specifies		created when EXCHANGE_ID specifies
	SP4_SSV protection. The only tokens		SP4_SSV protection. The only tokens
	defined are the PerMsgToken (emitted by GSS_GetMIC)		defined are the PerMsgToken (emitted by GSS_GetMIC)
	and the SealedMessage token (emitted by GSS_Wrap).		and the SealedMessage token (emitted by GSS_Wrap).
	</t>		</t>
	<t>		<t>
	The mechanism OID for the SSV mechanism is		The mechanism OID for the SSV mechanism is
	iso.org.dod.internet.private.enterprise.Michael		iso.org.dod.internet.private.enterprise.Michael
	Eisler.nfs.ssv_mech (1.3.6.1.4.1.28882.1.1). While the		Eisler.nfs.ssv_mech (1.3.6.1.4.1.28882.1.1). While the
	SSV mechanism does not define any initial context		SSV mechanism does not define any initial context
	tokens, the OID can be used to let servers indicate		tokens, the OID can be used to let servers indicate
	that the SSV mechanism is acceptable whenever the		that the SSV mechanism is acceptable whenever the
	client sends a SECINFO or SECINFO_NO_NAME operation		client sends a SECINFO or SECINFO_NO_NAME operation
	(see		(see
	<xref target="Security_Service_Negotiation" />).		<xref target="Security_Service_Negotiation" format="default"/>).
	</t>
	<t>		</t>
			<t>
	The SSV mechanism defines four subkeys derived from		The SSV mechanism defines four subkeys derived from
	the SSV value. Each time SET_SSV is invoked, the subkeys		the SSV value. Each time SET_SSV is invoked, the subkeys
	are recalculated by the client and server. The		are recalculated by the client and server. The
	calculation of each of the four subkeys depends on each		calculation of each of the four subkeys depends on each
	of the four respective ssv_subkey4 enumerated values. The calculation		of the four respective ssv_subkey4 enumerated values. The calculation
	uses the HMAC		uses the HMAC
	<xref target="RFC2104" /> algorithm, using the current SSV as the key, the on e-way hash		<xref target="RFC2104" format="default"/> algorithm, using the current SSV as the key, the one-way hash
	algorithm as negotiated by EXCHANGE_ID,		algorithm as negotiated by EXCHANGE_ID,
	and the input text as represented by the XDR encoded		and the input text as represented by the XDR encoded
	enumeration value for that subkey of data type ssv_subkey4.		enumeration value for that subkey of data type ssv_subkey4.
	If the length of the output of the HMAC algorithm exceeds the length of		If the length of the output of the HMAC algorithm exceeds the length of
	key of the encryption algorithm (which is also negotiated by EXCHANGE_ID),		key of the encryption algorithm (which is also negotiated by EXCHANGE_ID),
	then the subkey MUST be truncated from the HMAC output, i.e., if the		then the subkey <bcp14>MUST</bcp14> be truncated from the HMAC output, i.e., if the
	subkey is of N bytes long, then the first N bytes of the HMAC output		subkey is of N bytes long, then the first N bytes of the HMAC output
	MUST be used for the subkey. The specification of EXCHANGE_ID		<bcp14>MUST</bcp14> be used for the subkey. The specification of EXCHANGE_ID
	states that the length of the output of the HMAC algorithm MUST NOT		states that the length of the output of the HMAC algorithm <bcp14>MUST NOT</b
			cp14>
	be less than the length of subkey needed for the encryption algorithm		be less than the length of subkey needed for the encryption algorithm
	(see <xref target="OP_EXCHANGE_ID"/>).		(see <xref target="OP_EXCHANGE_ID" format="default"/>).
	</t>		</t>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	/* Input for computing subkeys */		/* Input for computing subkeys */
	enum ssv_subkey4 {		enum ssv_subkey4 {
	SSV4_SUBKEY_MIC_I2T = 1,		SSV4_SUBKEY_MIC_I2T = 1,
	SSV4_SUBKEY_MIC_T2I = 2,		SSV4_SUBKEY_MIC_T2I = 2,
	SSV4_SUBKEY_SEAL_I2T = 3,		SSV4_SUBKEY_SEAL_I2T = 3,
	SSV4_SUBKEY_SEAL_T2I = 4		SSV4_SUBKEY_SEAL_T2I = 4
	};		};
			]]></sourcecode>
	</artwork>		<t>
	</figure>
	<t>
	The subkey derived from SSV4_SUBKEY_MIC_I2T		The subkey derived from SSV4_SUBKEY_MIC_I2T
	is used for calculating message integrity codes (MICs)		is used for calculating message integrity codes (MICs)
	that originate from the NFSv4.1 client, whether as part		that originate from the NFSv4.1 client, whether as part
	of a request over the fore channel or a response		of a request over the fore channel or a response
	over the backchannel. The subkey derived from		over the backchannel. The subkey derived from
	SSV4_SUBKEY_MIC_T2I is used for MICs originating from the		SSV4_SUBKEY_MIC_T2I is used for MICs originating from the
	NFSv4.1 server. The subkey derived from SSV4_SUBKEY_SEAL_I2T		NFSv4.1 server. The subkey derived from SSV4_SUBKEY_SEAL_I2T
	is used for encryption text originating from the NFSv4.1		is used for encryption text originating from the NFSv4.1
	client, and the subkey derived from SSV4_SUBKEY_SEAL_T2I		client, and the subkey derived from SSV4_SUBKEY_SEAL_T2I
	is used for encryption text originating from the		is used for encryption text originating from the
	NFSv4.1 server.		NFSv4.1 server.
	</t>		</t>
	<t>		<t>
	The PerMsgToken description is based on an XDR definition:		The PerMsgToken description is based on an XDR definition:
	</t>		</t>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	/* Input for computing smt_hmac */		/* Input for computing smt_hmac */
	struct ssv_mic_plain_tkn4 {		struct ssv_mic_plain_tkn4 {
	uint32_t smpt_ssv_seq;		uint32_t smpt_ssv_seq;
	opaque smpt_orig_plain&lt;>;		opaque smpt_orig_plain<>;
	};		};
			]]></sourcecode>
	</artwork>		<sourcecode type="xdr"><![CDATA[
	</figure>
	<figure>
	<artwork>
	/* SSV GSS PerMsgToken token */		/* SSV GSS PerMsgToken token */
	struct ssv_mic_tkn4 {		struct ssv_mic_tkn4 {
	uint32_t smt_ssv_seq;		uint32_t smt_ssv_seq;
	opaque smt_hmac&lt;>;		opaque smt_hmac<>;
	};		};
			]]></sourcecode>
	</artwork>		<t>
	</figure>
	<t>
	The field smt_hmac is an HMAC calculated by using the		The field smt_hmac is an HMAC calculated by using the
	subkey derived from SSV4_SUBKEY_MIC_I2T or		subkey derived from SSV4_SUBKEY_MIC_I2T or
	SSV4_SUBKEY_MIC_T2I as the key, the one-way hash algorithm		SSV4_SUBKEY_MIC_T2I as the key, the one-way hash algorithm
	as negotiated by EXCHANGE_ID, and the input text		as negotiated by EXCHANGE_ID, and the input text
	as represented by data of type ssv_mic_plain_tkn4.		as represented by data of type ssv_mic_plain_tkn4.
	The field smpt_ssv_seq is the same as smt_ssv_seq.		The field smpt_ssv_seq is the same as smt_ssv_seq.
	The field smpt_orig_plain is the "message" input passed		The field smpt_orig_plain is the "message" input passed
	to GSS_GetMIC() (see Section 2.3.1 of <xref target="RFC2743"/>).		to GSS_GetMIC() (see <xref target="RFC2743" sectionFormat="of" section="2.3.1 "/>).
	The caller of GSS_GetMIC() provides a pointer to a buffer		The caller of GSS_GetMIC() provides a pointer to a buffer
	containing the plain text. The SSV mechanism's entry point for		containing the plain text. The SSV mechanism's entry point for
	GSS_GetMIC() encodes this into an opaque array, and the encoding		GSS_GetMIC() encodes this into an opaque array, and the encoding
	will include an initial four-byte length, plus any necessary padding.		will include an initial four-byte length, plus any necessary padding.
	Prepended to this will be the XDR encoded value of smpt_ssv_seq,		Prepended to this will be the XDR encoded value of smpt_ssv_seq,
	thus making up an XDR encoding of a value of data type		thus making up an XDR encoding of a value of data type
	ssv_mic_plain_tkn4, which in turn is the input into the HMAC.		ssv_mic_plain_tkn4, which in turn is the input into the HMAC.
	</t>		</t>
	<t>		<t>
	The token emitted by GSS_GetMIC() is XDR encoded and		The token emitted by GSS_GetMIC() is XDR encoded and
	of XDR data type ssv_mic_tkn4. The field smt_ssv_seq		of XDR data type ssv_mic_tkn4. The field smt_ssv_seq
	comes from the SSV sequence number, which is equal to		comes from the SSV sequence number, which is equal to
	one after SET_SSV (<xref target="OP_SET_SSV" />)		one after SET_SSV (<xref target="OP_SET_SSV" format="default"/>)
	is called the first time on a client		is called the first time on a client
	ID.		ID.
	Thereafter, the SSV sequence number is incremented on each SET_SSV.		Thereafter, the SSV sequence number is incremented on each SET_SSV.
	Thus, smt_ssv_seq represents the version of the SSV at		Thus, smt_ssv_seq represents the version of the SSV at
	the time GSS_GetMIC() was called. As noted in <xref		the time GSS_GetMIC() was called. As noted in <xref target="OP_EXCHANGE_ID"
	target="OP_EXCHANGE_ID" />, the client and server		format="default"/>, the client and server
	can maintain multiple concurrent versions of the SSV.		can maintain multiple concurrent versions of the SSV.
	This allows the SSV to be changed without serializing		This allows the SSV to be changed without serializing
	all RPC calls that use the SSV mechanism with SET_SSV		all RPC calls that use the SSV mechanism with SET_SSV
	operations.		operations.
	Once the HMAC is calculated, it is XDR encoded into		Once the HMAC is calculated, it is XDR encoded into
	smt_hmac, which will include an initial four-byte length,		smt_hmac, which will include an initial four-byte length,
	and any necessary padding. Prepended to this will be		and any necessary padding. Prepended to this will be
	the XDR encoded value of smt_ssv_seq.		the XDR encoded value of smt_ssv_seq.
	</t>		</t>
	<t>		<t>
	The SealedMessage description is based on an XDR definition:		The SealedMessage description is based on an XDR definition:
	</t>		</t>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	/* Input for computing ssct_encr_data and ssct_hmac */		/* Input for computing ssct_encr_data and ssct_hmac */
	struct ssv_seal_plain_tkn4 {		struct ssv_seal_plain_tkn4 {
	opaque sspt_confounder&lt;>;		opaque sspt_confounder<>;
	uint32_t sspt_ssv_seq;		uint32_t sspt_ssv_seq;
	opaque sspt_orig_plain&lt;>;		opaque sspt_orig_plain<>;
	opaque sspt_pad&lt;>;		opaque sspt_pad<>;
	};		};
			]]></sourcecode>
	</artwork>		<sourcecode type="xdr"><![CDATA[
	</figure>
	<figure>
	<artwork>
	/* SSV GSS SealedMessage token */		/* SSV GSS SealedMessage token */
	struct ssv_seal_cipher_tkn4 {		struct ssv_seal_cipher_tkn4 {
	uint32_t ssct_ssv_seq;		uint32_t ssct_ssv_seq;
	opaque ssct_iv&lt;>;		opaque ssct_iv<>;
	opaque ssct_encr_data&lt;>;		opaque ssct_encr_data<>;
	opaque ssct_hmac&lt;>;		opaque ssct_hmac<>;
	};		};
			]]></sourcecode>
	</artwork>		<t>
	</figure>
	<t>
	The token emitted by GSS_Wrap() is XDR encoded and		The token emitted by GSS_Wrap() is XDR encoded and
	of XDR data type ssv_seal_cipher_tkn4.		of XDR data type ssv_seal_cipher_tkn4.
	</t>		</t>
			<t>
	<t>
	The ssct_ssv_seq field has the same meaning as smt_ssv_seq.		The ssct_ssv_seq field has the same meaning as smt_ssv_seq.
	</t>		</t>
			<t>
	<t>
	The ssct_encr_data field is the result of encrypting a		The ssct_encr_data field is the result of encrypting a
	value of the XDR encoded data type ssv_seal_plain_tkn4.		value of the XDR encoded data type ssv_seal_plain_tkn4.
	The encryption key is the subkey derived from SSV4_SUBKEY_SEAL_I2T		The encryption key is the subkey derived from SSV4_SUBKEY_SEAL_I2T
	or SSV4_SUBKEY_SEAL_T2I, and the encryption		or SSV4_SUBKEY_SEAL_T2I, and the encryption
	algorithm is that negotiated by EXCHANGE_ID.		algorithm is that negotiated by EXCHANGE_ID.
	</t>		</t>
			<t>
	<t>
	The ssct_iv field is the initialization vector (IV)		The ssct_iv field is the initialization vector (IV)
	for the encryption algorithm (if applicable) and is		for the encryption algorithm (if applicable) and is
	sent in clear text. The content and size of the IV MUST		sent in clear text. The content and size of the IV <bcp14>MUST</bcp14>
	comply with the specification of the encryption algorithm.		comply with the specification of the encryption algorithm.
	For example, the id-aes256-CBC algorithm MUST use		For example, the id-aes256-CBC algorithm <bcp14>MUST</bcp14> use
	a 16-byte initialization vector (IV), which MUST be		a 16-byte initialization vector (IV), which <bcp14>MUST</bcp14> be
	unpredictable for each instance of a value of data type		unpredictable for each instance of a value of data type
	ssv_seal_plain_tkn4 that is encrypted with a particular		ssv_seal_plain_tkn4 that is encrypted with a particular
	SSV key.		SSV key.
	</t>		</t>
	<t>		<t>
	The ssct_hmac field is the result of computing an HMAC using the value		The ssct_hmac field is the result of computing an HMAC using the value
	of the XDR encoded data type ssv_seal_plain_tkn4 as the input		of the XDR encoded data type ssv_seal_plain_tkn4 as the input
	text. The key is the subkey derived from SSV4_SUBKEY_MIC_I2T or		text. The key is the subkey derived from SSV4_SUBKEY_MIC_I2T or
	SSV4_SUBKEY_MIC_T2I, and the one-way hash algorithm is that		SSV4_SUBKEY_MIC_T2I, and the one-way hash algorithm is that
	negotiated by EXCHANGE_ID.		negotiated by EXCHANGE_ID.
	</t>		</t>
	<t>		<t>
	The sspt_confounder field is a random value.		The sspt_confounder field is a random value.
	</t>		</t>
	<t>		<t>
	The sspt_ssv_seq field is the same as ssvt_ssv_seq.		The sspt_ssv_seq field is the same as ssvt_ssv_seq.
	</t>		</t>
	<t>		<t>
	The field sspt_orig_plain field is the original plaintext		The field sspt_orig_plain field is the original plaintext
	and is the "input_message" input passed to		and is the "input_message" input passed to
	GSS_Wrap() (see Section 2.3.3 of <xref target="RFC2743"/>).		GSS_Wrap() (see <xref target="RFC2743" sectionFormat="of" section="2.3.3"/>).
	As with the handling of the plaintext by the SSV mechanism's		As with the handling of the plaintext by the SSV mechanism's
	GSS_GetMIC() entry point, the entry point for GSS_Wrap()		GSS_GetMIC() entry point, the entry point for GSS_Wrap()
	expects a pointer to the plaintext, and will XDR encode		expects a pointer to the plaintext, and will XDR encode
	an opaque array into sspt_orig_plain		an opaque array into sspt_orig_plain
	representing the plain text, along with		representing the plain text, along with
	the other fields of an instance of data type ssv_seal_plain_tkn4.		the other fields of an instance of data type ssv_seal_plain_tkn4.
	</t>		</t>
	<t>		<t>
	The sspt_pad field is present to support encryption		The sspt_pad field is present to support encryption
	algorithms that require inputs to be in fixed-sized		algorithms that require inputs to be in fixed-sized
	blocks. The content of sspt_pad is zero filled		blocks. The content of sspt_pad is zero filled
	except for the length. Beware that the XDR encoding		except for the length. Beware that the XDR encoding
	of ssv_seal_plain_tkn4 contains three variable-length		of ssv_seal_plain_tkn4 contains three variable-length
	arrays, and so each array consumes four bytes for an		arrays, and so each array consumes four bytes for an
	array length, and each array that follows the length		array length, and each array that follows the length
	is always padded to a multiple of four bytes per the		is always padded to a multiple of four bytes per the
	XDR standard.		XDR standard.
	</t>		</t>
	<t>		<t>
	For example, suppose the encryption algorithm uses 16-byte blocks, and		For example, suppose the encryption algorithm uses 16-byte blocks, and
	the sspt_confounder is three bytes long, and		the sspt_confounder is three bytes long, and
	the sspt_orig_plain field is 15 bytes long.		the sspt_orig_plain field is 15 bytes long.
	The XDR encoding of sspt_confounder uses eight bytes		The XDR encoding of sspt_confounder uses eight bytes
	(4 + 3 + 1-byte pad),		(4 + 3 + 1-byte pad),
	the XDR encoding of sspt_ssv_seq uses four bytes,		the XDR encoding of sspt_ssv_seq uses four bytes,
	the XDR encoding of sspt_orig_plain uses 20 bytes		the XDR encoding of sspt_orig_plain uses 20 bytes
	skipping to change at line 4842 ¶		skipping to change at line 4791 ¶
	and the smallest XDR encoding of the sspt_pad field		and the smallest XDR encoding of the sspt_pad field
	is four bytes.		is four bytes.
	This totals 36 bytes. The next multiple of 16 is 48;		This totals 36 bytes. The next multiple of 16 is 48;
	thus, the length field of sspt_pad needs to be set to		thus, the length field of sspt_pad needs to be set to
	12 bytes, or a total encoding of 16 bytes.		12 bytes, or a total encoding of 16 bytes.
	The total number of XDR encoded bytes is thus 8 +		The total number of XDR encoded bytes is thus 8 +
	4 + 20 + 16 = 48.		4 + 20 + 16 = 48.
	</t>		</t>
	<t>		<t>
	GSS_Wrap() emits a token that is an XDR		GSS_Wrap() emits a token that is an XDR
	encoding of a value of data type ssv_seal_cipher_tkn4.		encoding of a value of data type ssv_seal_cipher_tkn4.
	Note that regardless of whether or not the caller of GSS_Wrap()		Note that regardless of whether or not the caller of GSS_Wrap()
	requests confidentiality, the token always has		requests confidentiality, the token always has
	confidentiality. This is because the SSV mechanism		confidentiality. This is because the SSV mechanism
	is for RPCSEC_GSS, and RPCSEC_GSS never produces		is for RPCSEC_GSS, and RPCSEC_GSS never produces
	GSS_wrap() tokens without confidentiality.		GSS_wrap() tokens without confidentiality.
	</t>		</t>
	<t>		<t>
	There is one SSV per client ID.		There is one SSV per client ID.
	There is a single GSS context for		There is a single GSS context for
	a client ID / SSV pair.		a client ID / SSV pair.
	All SSV mechanism RPCSEC_GSS handles of a client ID / SSV pair		All SSV mechanism RPCSEC_GSS handles of a client ID / SSV pair
	share the same GSS context.		share the same GSS context.
	SSV GSS contexts do not expire except when the SSV		SSV GSS contexts do not expire except when the SSV
	is destroyed (causes would include the client ID		is destroyed (causes would include the client ID
	being destroyed or a server restart).		being destroyed or a server restart).
	Since one		Since one
	purpose of context expiration is to replace keys that		purpose of context expiration is to replace keys that
	have been in use for "too long", hence vulnerable to		have been in use for "too long", hence vulnerable to
	compromise by brute force or accident, the client can		compromise by brute force or accident, the client can
	replace the SSV key by		replace the SSV key by
	sending periodic SET_SSV operations, which is done by cycling through		sending periodic SET_SSV operations, which is done by cycling through
	different users' RPCSEC_GSS credentials. This way, the SSV is		different users' RPCSEC_GSS credentials. This way, the SSV is
	replaced without destroying the SSV's GSS contexts.		replaced without destroying the SSV's GSS contexts.
	</t>		</t>
	<t>		<t>
	SSV RPCSEC_GSS handles can be expired or deleted by the server		SSV RPCSEC_GSS handles can be expired or deleted by the server
	at any time, and the EXCHANGE_ID operation can be used to create		at any time, and the EXCHANGE_ID operation can be used to create
	more SSV RPCSEC_GSS handles. Expiration of SSV RPCSEC_GSS handles		more SSV RPCSEC_GSS handles. Expiration of SSV RPCSEC_GSS handles
	does not imply that the SSV or its GSS context has expired.		does not imply that the SSV or its GSS context has expired.
	</t>		</t>
	<t>		<t>
	The client MUST establish an SSV via SET_SSV before the		The client <bcp14>MUST</bcp14> establish an SSV via SET_SSV before the
	SSV GSS context can be used to emit tokens from GSS_Wrap()		SSV GSS context can be used to emit tokens from GSS_Wrap()
	and GSS_GetMIC(). If SET_SSV has not been successfully		and GSS_GetMIC(). If SET_SSV has not been successfully
	called, attempts to emit tokens MUST fail.		called, attempts to emit tokens <bcp14>MUST</bcp14> fail.
	</t>		</t>
	<t>		<t>
	The SSV mechanism does not support replay detection and sequencing		The SSV mechanism does not support replay detection and sequencing
	in its tokens because RPCSEC_GSS does not use those features (See		in its tokens because RPCSEC_GSS does not use those features (see
	Section 5.2.2, "Context Creation Requests", in <xref target="RFC2203"		"Context Creation Requests", <xref target="RFC2203" sectionFormat="of" sectio
	/>). However, <xref target="rpcsec_ssv_consider"/> discusses special		n="5.2.2"/>). However, <xref target="rpcsec_ssv_consider" format="default"/> dis
			cusses special
	considerations for the SSV mechanism when used with RPCSEC_GSS.		considerations for the SSV mechanism when used with RPCSEC_GSS.
	</t>		</t>
	</section> <!-- The SSV GSS Mechanism -->		</section>
	<section anchor="rpcsec_ssv_consider"		<section anchor="rpcsec_ssv_consider" numbered="true" toc="default">
	title="Security Considerations for RPCSEC_GSS When Using the SSV Mecha		<name>Security Considerations for RPCSEC_GSS When Using the SSV Mechan
	nism">		ism</name>
	<t>		<t>
	When a client ID is created with SP4_SSV state protection (see <xref		When a client ID is created with SP4_SSV state protection (see <xref target=
	target="OP_EXCHANGE_ID"/>), the client is permitted to associate		"OP_EXCHANGE_ID" format="default"/>), the client is permitted to associate
	multiple RPCSEC_GSS handles with the single SSV GSS context		multiple RPCSEC_GSS handles with the single SSV GSS context
	(see <xref target="ssv_mech"/>). Because of the way RPCSEC_GSS		(see <xref target="ssv_mech" format="default"/>). Because of the way RPCSEC_
	(both version 1 and version 2, see <xref target="RFC2203"/> and		GSS
	<xref target="RFC5403"/>) calculate the verifier of the reply,		(both version 1 and version 2, see <xref target="RFC2203" format="default"/>
			and
			<xref target="RFC5403" format="default"/>) calculate the verifier of the rep
			ly,
	special care must be taken by the implementation of the NFSv4.1		special care must be taken by the implementation of the NFSv4.1
	client to prevent attacks by a man-in-the-middle. The verifier		client to prevent attacks by a man-in-the-middle. The verifier
	of an RPCSEC_GSS reply is the output of GSS_GetMIC() applied to		of an RPCSEC_GSS reply is the output of GSS_GetMIC() applied to
	the input value of the seq_num field of the RPCSEC_GSS credential		the input value of the seq_num field of the RPCSEC_GSS credential
	(data type rpc_gss_cred_ver_1_t) (see Section 5.3.3.2 of <xref		(data type rpc_gss_cred_ver_1_t) (see <xref target="RFC2203" sectionFormat="
	target="RFC2203"/>). If multiple RPCSEC_GSS handles share the same		of" section="5.3.3.2"/>). If multiple RPCSEC_GSS handles share
			the same
	GSS context, then if one handle is used to send a request with the		GSS context, then if one handle is used to send a request with the
	same seq_num value as another handle, an attacker could block the		same seq_num value as another handle, an attacker could block the
	reply, and replace it with the verifier used for the other handle.		reply, and replace it with the verifier used for the other handle.
	</t>		</t>
			<t>
	<t>
	There are multiple ways to prevent the attack on the SSV RPCSEC_GSS		There are multiple ways to prevent the attack on the SSV RPCSEC_GSS
	verifier in the reply. The simplest is believed to be as follows.		verifier in the reply. The simplest is believed to be as follows.
	<list style='symbols'>		</t>
			<ul spacing="normal">
	<t>		<li>
	Each time one or more new SSV RPCSEC_GSS handles are created via		Each time one or more new SSV RPCSEC_GSS handles are created via
	EXCHANGE_ID, the client SHOULD send a SET_SSV operation to modify		EXCHANGE_ID, the client <bcp14>SHOULD</bcp14> send a SET_SSV operation to mod ify
	the SSV. By changing the SSV, the new handles will not result in the		the SSV. By changing the SSV, the new handles will not result in the
	re-use of an SSV RPCSEC_GSS verifier in a reply.		re-use of an SSV RPCSEC_GSS verifier in a reply.
	</t>		</li>
			<li>
	<t>		When a requester decides to use N SSV RPCSEC_GSS handles, it <bcp14>SHOULD</b
	When a requester decides to use N SSV RPCSEC_GSS handles, it SHOULD		cp14>
	assign a unique and non-overlapping range of seq_nums to each SSV		assign a unique and non-overlapping range of seq_nums to each SSV
	RPCSEC_GSS handle. The size of each range SHOULD be equal to MAXSEQ		RPCSEC_GSS handle. The size of each range <bcp14>SHOULD</bcp14> be equal to M
	/ N (see Section 5 of <xref target="RFC2203"/> for the definition		AXSEQ
			/ N (see <xref target="RFC2203" sectionFormat="of" section="5"/> for the defi
			nition
	of MAXSEQ). When an SSV RPCSEC_GSS handle reaches its maximum, it		of MAXSEQ). When an SSV RPCSEC_GSS handle reaches its maximum, it
	SHOULD force the replier to destroy the handle by sending a NULL		<bcp14>SHOULD</bcp14> force the replier to destroy the handle by sending a NU
	RPC request with seq_num set to MAXSEQ + 1 (see Section 5.3.3.3 of		LL
	<xref target="RFC2203"/>).		RPC request with seq_num set to MAXSEQ + 1 (see
			<xref target="RFC2203" sectionFormat="of" section="5.3.3.3"/>).
	</t>
	<t>		</li>
	When the requester wants to increase or decrease N, it SHOULD force		<li>
			When the requester wants to increase or decrease N, it <bcp14>SHOULD</bcp14>
			force
	the replier to destroy all N handles by sending a NULL RPC request on		the replier to destroy all N handles by sending a NULL RPC request on
	each handle with seq_num set to MAXSEQ + 1. If the requester is the		each handle with seq_num set to MAXSEQ + 1. If the requester is the
	client, it SHOULD send a SET_SSV operation before using new handles.		client, it <bcp14>SHOULD</bcp14> send a SET_SSV operation before using new ha
	If the requester is the server, then the client SHOULD send a SET_SSV		ndles.
			If the requester is the server, then the client <bcp14>SHOULD</bcp14> send a
			SET_SSV
	operation when it detects that the server has forced it to destroy a		operation when it detects that the server has forced it to destroy a
	backchannel's SSV RPCSEC_GSS handle. By sending a SET_SSV operation,		backchannel's SSV RPCSEC_GSS handle. By sending a SET_SSV operation,
	the SSV will change, and so the attacker will be unavailable to		the SSV will change, and so the attacker will be unavailable to
	successfully replay a previous verifier in a reply to the requester.		successfully replay a previous verifier in a reply to the requester.
	</t>		</li>
			</ul>
	</list>		<t>
	</t>
	<t>
	Note that if the replier carefully creates the SSV RPCSEC_GSS		Note that if the replier carefully creates the SSV RPCSEC_GSS
	handles, the related risk of a man-in-the-middle splicing a forged		handles, the related risk of a man-in-the-middle splicing a forged
	SSV RPCSEC_GSS credential with a verifier for another handle does		SSV RPCSEC_GSS credential with a verifier for another handle does
	not exist. This is because the verifier in an RPCSEC_GSS request		not exist. This is because the verifier in an RPCSEC_GSS request
	is computed from input that includes both the RPCSEC_GSS handle and		is computed from input that includes both the RPCSEC_GSS handle and
	seq_num (see Section 5.3.1 of <xref target="RFC2203"/>). Provided the		seq_num (see <xref target="RFC2203" sectionFormat="of" section="5.3.1"/>). P rovided the
	replier takes care to avoid re-using the value of an RPCSEC_GSS		replier takes care to avoid re-using the value of an RPCSEC_GSS
	handle that it creates, such as by including a generation number in the		handle that it creates, such as by including a generation number in the
	handle, the man-in-the-middle will not be able to successfully replay		handle, the man-in-the-middle will not be able to successfully replay
	a previous verifier in the request to a replier.		a previous verifier in the request to a replier.
	</t>		</t>
			</section>
	</section>		<section anchor="Session_Mechanics_Steady_State" numbered="true" toc="de
			fault">
	<section anchor="Session_Mechanics_Steady_State" title="Session Mechanics - St		<name>Session Mechanics - Steady State</name>
	eady State">		<section anchor="Obligations_of_the_Server" numbered="true" toc="defau
			lt">
	<section anchor="Obligations_of_the_Server" title="Obligations of the Server"		<name>Obligations of the Server</name>
	>		<t>
	<t>
	The server has the primary obligation to monitor the		The server has the primary obligation to monitor the
	state of backchannel resources that the client has		state of backchannel resources that the client has
	created for the server (RPCSEC_GSS contexts and backchannel		created for the server (RPCSEC_GSS contexts and backchannel
	connections). If these resources vanish, the		connections). If these resources vanish, the
	server takes action as specified in <xref target="Events_Requiring_Server_Ac		server takes action as specified in <xref target="Events_Requiring_Server_Ac
	tion" />.		tion" format="default"/>.
	</t>		</t>
	</section> <!-- Obligations of the Server -->		</section>
	<section anchor="Obligations_of_the_Client" title="Obligations of the Client"		<section anchor="Obligations_of_the_Client" numbered="true" toc="default">
	>		<name>Obligations of the Client</name>
	<t>		<t>
	The client SHOULD honor the following obligations in order to		The client <bcp14>SHOULD</bcp14> honor the following obligations in order to
	utilize the session:		utilize the session:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Keep a necessary session from going idle on the server. A client		Keep a necessary session from going idle on the server. A client
	that requires a session but nonetheless is not		that requires a session but nonetheless is not
	sending operations risks having the session be destroyed		sending operations risks having the session be destroyed
	by the server. This is because sessions consume		by the server. This is because sessions consume
	resources, and resource limitations may force the		resources, and resource limitations may force the
	server to cull an inactive session. A server MAY consider		server to cull an inactive session. A server <bcp14>MAY</bcp14> consider
	a session to be inactive if the client has not used		a session to be inactive if the client has not used
	the session before the session inactivity timer (<xref		the session before the session inactivity timer (<xref target="session_inac
	target="session_inactive"/>) has expired.		tive" format="default"/>) has expired.
	</t>		</li>
	<t>		<li>
	Destroy the session when not needed. If a client has		Destroy the session when not needed. If a client has
	multiple sessions, one of which has no		multiple sessions, one of which has no
	requests waiting for replies, and has been idle for		requests waiting for replies, and has been idle for
	some period of time, it SHOULD destroy the session.		some period of time, it <bcp14>SHOULD</bcp14> destroy the session.
	</t>		</li>
	<t>		<li>
	Maintain GSS contexts and RPCSEC_GSS handles		Maintain GSS contexts and RPCSEC_GSS handles
	for the backchannel. If the client		for the backchannel. If the client
	requires the server to use the RPCSEC_GSS security		requires the server to use the RPCSEC_GSS security
	flavor for callbacks, then it needs to be sure the		flavor for callbacks, then it needs to be sure the
	RPCSEC_GSS handles and/or their GSS		RPCSEC_GSS handles and/or their GSS
	contexts that are handed to the server via BACKCHANNEL_CTL or		contexts that are handed to the server via BACKCHANNEL_CTL or
	CREATE_SESSION are unexpired.		CREATE_SESSION are unexpired.
	</t>		</li>
	<t>		<li>
	Preserve a connection for a backchannel. The server		Preserve a connection for a backchannel. The server
	requires a backchannel in order to gracefully recall		requires a backchannel in order to gracefully recall
	recallable state or notify the client of certain		recallable state or notify the client of certain
	events. Note that if the connection is not being used		events. Note that if the connection is not being used
	for the fore channel, there is no way for the client to tell		for the fore channel, there is no way for the client to tell
	if the connection is still alive (e.g., the server		if the connection is still alive (e.g., the server
	restarted without sending a disconnect). The onus is		restarted without sending a disconnect). The onus is
	on the server, not the client, to determine if the		on the server, not the client, to determine if the
	backchannel's connection is alive, and to indicate in		backchannel's connection is alive, and to indicate in
	the response to a SEQUENCE operation when the last		the response to a SEQUENCE operation when the last
	connection associated with a session's backchannel		connection associated with a session's backchannel
	has disconnected.		has disconnected.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section> <!-- Obligations of the Client -->
	<section anchor="Steps_the_Client_Takes_To_Establish_a_Session"		<section anchor="Steps_the_Client_Takes_To_Establish_a_Session" numbered="tru
	title="Steps the Client Takes to Establish a Session">		e" toc="default">
	<t>		<name>Steps the Client Takes to Establish a Session</name>
			<t>
	If the client does not have a client ID, the client		If the client does not have a client ID, the client
	sends EXCHANGE_ID to establish a client ID. If it		sends EXCHANGE_ID to establish a client ID. If it
	opts for SP4_MACH_CRED or SP4_SSV protection, in the		opts for SP4_MACH_CRED or SP4_SSV protection, in the
	spo_must_enforce list of operations, it SHOULD at		spo_must_enforce list of operations, it <bcp14>SHOULD</bcp14> at
	minimum specify CREATE_SESSION, DESTROY_SESSION,		minimum specify CREATE_SESSION, DESTROY_SESSION,
	BIND_CONN_TO_SESSION, BACKCHANNEL_CTL, and DESTROY_CLIENTID.		BIND_CONN_TO_SESSION, BACKCHANNEL_CTL, and DESTROY_CLIENTID.
	If it opts for SP4_SSV protection, the client needs to		If it opts for SP4_SSV protection, the client needs to
	ask for SSV-based RPCSEC_GSS handles.		ask for SSV-based RPCSEC_GSS handles.
	</t>		</t>
	<t>		<t>
	The client uses the client ID to send a		The client uses the client ID to send a
	CREATE_SESSION on a connection to the server.		CREATE_SESSION on a connection to the server.
	The results of CREATE_SESSION indicate whether or not the		The results of CREATE_SESSION indicate whether or not the
	server will persist the session reply cache through		server will persist the session reply cache through
	a server that has restarted, and the client notes this		a server that has restarted, and the client notes this
	for future reference.		for future reference.
	</t>		</t>
	<t>		<t>
	If the client specified SP4_SSV state protection		If the client specified SP4_SSV state protection
	when the client ID was created, then it SHOULD send		when the client ID was created, then it <bcp14>SHOULD</bcp14> send
	SET_SSV in the first COMPOUND after the session is		SET_SSV in the first COMPOUND after the session is
	created. Each time a new principal goes to use the		created. Each time a new principal goes to use the
	client ID, it SHOULD send a SET_SSV again.		client ID, it <bcp14>SHOULD</bcp14> send a SET_SSV again.
	</t>		</t>
	<t>		<t>
	If the client wants to use delegations, layouts,		If the client wants to use delegations, layouts,
	directory notifications, or any other state that		directory notifications, or any other state that
	requires a backchannel, then it needs to add a connection		requires a backchannel, then it needs to add a connection
	to the backchannel if CREATE_SESSION did not already		to the backchannel if CREATE_SESSION did not already
	do so. The client creates a connection, and calls		do so. The client creates a connection, and calls
	BIND_CONN_TO_SESSION to associate the connection		BIND_CONN_TO_SESSION to associate the connection
	with the session and the session's backchannel. If		with the session and the session's backchannel. If
	CREATE_SESSION did not already do so, the client MUST		CREATE_SESSION did not already do so, the client <bcp14>MUST</bcp14>
	tell the server what security is required in order		tell the server what security is required in order
	for the client to accept callbacks. The client does		for the client to accept callbacks. The client does
	this via BACKCHANNEL_CTL. If the client selected		this via BACKCHANNEL_CTL. If the client selected
	SP4_MACH_CRED or SP4_SSV protection when it called		SP4_MACH_CRED or SP4_SSV protection when it called
	EXCHANGE_ID, then the client SHOULD specify that the		EXCHANGE_ID, then the client <bcp14>SHOULD</bcp14> specify that the
	backchannel use RPCSEC_GSS contexts for security.		backchannel use RPCSEC_GSS contexts for security.
	</t>		</t>
	<t>		<t>
	If the client wants to use additional		If the client wants to use additional
	connections for the backchannel, then it needs to call		connections for the backchannel, then it needs to call
	BIND_CONN_TO_SESSION on each connection it wants to		BIND_CONN_TO_SESSION on each connection it wants to
	use with the session. If the client wants to use		use with the session. If the client wants to use
	additional connections for the fore channel, then		additional connections for the fore channel, then
	it needs to call BIND_CONN_TO_SESSION if it specified		it needs to call BIND_CONN_TO_SESSION if it specified
	SP4_SSV or SP4_MACH_CRED state protection when the		SP4_SSV or SP4_MACH_CRED state protection when the
	client ID was created.		client ID was created.
	</t>		</t>
			<t>
	<t>
	At this point, the session has reached steady state.		At this point, the session has reached steady state.
	</t>		</t>
	</section> <!-- Steps the Client Takes To Establish a Session -->		</section>
	</section> <!-- Session Mechanics - Steady State -->		</section>
	<section anchor="session_inactive" title="Session Inactivity Timer" >		<section anchor="session_inactive" numbered="true" toc="default">
	<t>		<name>Session Inactivity Timer</name>
	The server MAY maintain a session inactivity timer for		<t>
			The server <bcp14>MAY</bcp14> maintain a session inactivity timer for
	each session. If the session inactivity timer expires,		each session. If the session inactivity timer expires,
	then the server MAY destroy the session. To avoid losing		then the server <bcp14>MAY</bcp14> destroy the session. To avoid losing
	a session due to inactivity, the client MUST renew		a session due to inactivity, the client <bcp14>MUST</bcp14> renew
	the session inactivity timer. The length of session		the session inactivity timer. The length of session
	inactivity timer MUST NOT be less than the lease_time		inactivity timer <bcp14>MUST NOT</bcp14> be less than the lease_time
	attribute (<xref target="attrdef_lease_time"/>).		attribute (<xref target="attrdef_lease_time" format="default"/>).
	As with lease renewal (<xref target="lease_renewal"/>),		As with lease renewal (<xref target="lease_renewal" format="default"/>),
	when the server receives a SEQUENCE operation,		when the server receives a SEQUENCE operation,
	it resets the session inactivity timer, and MUST NOT allow the		it resets the session inactivity timer, and <bcp14>MUST NOT</bcp14> allow the
	timer to expire while the rest of the operations in the		timer to expire while the rest of the operations in the
	COMPOUND procedure's request are still executing. Once the		COMPOUND procedure's request are still executing. Once the
	last operation has finished, the server MUST set the session		last operation has finished, the server <bcp14>MUST</bcp14> set the session
	inactivity timer to expire no sooner than the sum of the		inactivity timer to expire no sooner than the sum of the
	current time and the value of the lease_time attribute.		current time and the value of the lease_time attribute.
	</t>		</t>
			</section>
	</section>		<section anchor="Session_Mechanics_Recovery" numbered="true" toc="defaul
	<section anchor="Session_Mechanics_Recovery" title="Session Mechanics - Recove		t">
	ry">		<name>Session Mechanics - Recovery</name>
			<section anchor="Events_Requiring_Client_Action" numbered="true" toc="
	<section anchor="Events_Requiring_Client_Action" title="Events Requiring Clie		default">
	nt Action">		<name>Events Requiring Client Action</name>
			<t>
	<t>
	The following events require client action to recover.		The following events require client action to recover.
	</t>		</t>
	<section title="RPCSEC_GSS Context Loss by Callback Path">		<section numbered="true" toc="default">
	<t>		<name>RPCSEC_GSS Context Loss by Callback Path</name>
			<t>
	If all RPCSEC_GSS handles		If all RPCSEC_GSS handles
	granted by the client to the server for callback use have		granted by the client to the server for callback use have
	expired, the client MUST		expired, the client <bcp14>MUST</bcp14>
	establish a new handle via BACKCHANNEL_CTL. The		establish a new handle via BACKCHANNEL_CTL. The
	sr_status_flags field of the SEQUENCE results indicates when callback handle s		sr_status_flags field of the SEQUENCE results indicates when callback handle s
	are nearly expired, or fully expired (see <xref target="OP_SEQUENCE_DESCRIPT		are nearly expired, or fully expired (see <xref target="OP_SEQUENCE_DESCRIPT
	ION"/>).		ION" format="default"/>).
	</t>		</t>
	</section> <!-- RPCSEC_GSS Context Loss by Callback_Path -->		</section>
	<section title="Connection Loss">		<section numbered="true" toc="default">
	<t>		<name>Connection Loss</name>
			<t>
	If the client loses the last connection of the session		If the client loses the last connection of the session
	and wants to retain the session, then it needs to		and wants to retain the session, then it needs to
	create a new connection, and if, when the client		create a new connection, and if, when the client
	ID was created, BIND_CONN_TO_SESSION was specified		ID was created, BIND_CONN_TO_SESSION was specified
	in the spo_must_enforce list, the client MUST use		in the spo_must_enforce list, the client <bcp14>MUST</bcp14> use
	BIND_CONN_TO_SESSION to associate the connection with		BIND_CONN_TO_SESSION to associate the connection with
	the session.		the session.
	</t>		</t>
	<t>		<t>
	If there was a request outstanding at the time		If there was a request outstanding at the time
	of connection loss, then if the client wants to continue		of connection loss, then if the client wants to continue
	to use the session, it MUST retry the request, as		to use the session, it <bcp14>MUST</bcp14> retry the request, as
	described in		described in
	<xref target="Retry_and_Replay" />. Note that it		<xref target="Retry_and_Replay" format="default"/>. Note that it
	is not necessary to retry requests over a connection		is not necessary to retry requests over a connection
	with the same source network address or the same		with the same source network address or the same
	destination network address as the lost connection. As		destination network address as the lost connection. As
	long as the session ID, slot ID, and sequence ID in the		long as the session ID, slot ID, and sequence ID in the
	retry match that of the original request, the server		retry match that of the original request, the server
	will recognize the request as a retry if it executed		will recognize the request as a retry if it executed
	the request prior to disconnect.		the request prior to disconnect.
	</t>		</t>
	<t>		<t>
	If the connection that was lost was the last one associated with		If the connection that was lost was the last one associated with
	the backchannel, and the client wants to retain the backchannel and/or		the backchannel, and the client wants to retain the backchannel and/or
	prevent revocation of recallable state, the client needs to		prevent revocation of recallable state, the client needs to
	reconnect, and if it does, it		reconnect, and if it does, it
	MUST associate the connection to the session and backchannel via		<bcp14>MUST</bcp14> associate the connection to the session and backchannel via
	BIND_CONN_TO_SESSION.		BIND_CONN_TO_SESSION.
	The server SHOULD indicate when it has no callback connection		The server <bcp14>SHOULD</bcp14> indicate when it has no callback connection
	via the sr_status_flags result from SEQUENCE.		via the sr_status_flags result from SEQUENCE.
	</t>		</t>
	</section> <!-- Connection Disconnect -->		</section>
	<section title="Backchannel GSS Context Loss">		<section numbered="true" toc="default">
	<t>		<name>Backchannel GSS Context Loss</name>
			<t>
	Via the sr_status_flags result of the SEQUENCE operation or		Via the sr_status_flags result of the SEQUENCE operation or
	other means, the client will learn if some or all of		other means, the client will learn if some or all of
	the RPCSEC_GSS contexts it assigned to the backchannel have		the RPCSEC_GSS contexts it assigned to the backchannel have
	been lost. If the client wants to retain the backchannel and/or		been lost. If the client wants to retain the backchannel and/or
	not put recallable state subject to revocation,		not put recallable state subject to revocation,
	the client needs to use BACKCHANNEL_CTL to		the client needs to use BACKCHANNEL_CTL to
	assign new contexts.		assign new contexts.
	</t>		</t>
	</section> <!-- Backchannel GSS Context Loss -->		</section>
	<section anchor="loss_of_session" title="Loss of Session">		<section anchor="loss_of_session" numbered="true" toc="default">
	<t>		<name>Loss of Session</name>
			<t>
	The replier might lose a record of the session. Causes include:		The replier might lose a record of the session. Causes include:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Replier failure and restart.		Replier failure and restart.
	</t>		</li>
	<t>		<li>
	A catastrophe that causes the reply cache to be corrupted or		A catastrophe that causes the reply cache to be corrupted or
	lost on the media on which it was stored. This applies		lost on the media on which it was stored. This applies
	even if the replier indicated in the CREATE_SESSION results		even if the replier indicated in the CREATE_SESSION results
	that it would persist the cache.		that it would persist the cache.
	</t>		</li>
	<t>		<li>
	The server purges the session of a client that has been		The server purges the session of a client that has been
	inactive for a very extended period of time.		inactive for a very extended period of time.
	</t>		</li>
	<t>		<li>
	As a result of configuration changes among a set of clustered		As a result of configuration changes among a set of clustered
	servers, a network address previously connected to one		servers, a network address previously connected to one
	server becomes connected to a different server that has		server becomes connected to a different server that has
	no knowledge of the session in question. Such a configuration		no knowledge of the session in question. Such a configuration
	change will generally only happen when the original server		change will generally only happen when the original server
	ceases to function for a time.		ceases to function for a time.
	</t>		</li>
	</list>		</ul>
			<t>
	Loss of reply cache is equivalent to loss of session.		Loss of reply cache is equivalent to loss of session.
	The replier indicates loss of session to the requester		The replier indicates loss of session to the requester
	by returning NFS4ERR_BADSESSION on the next operation		by returning NFS4ERR_BADSESSION on the next operation
	that uses the session ID that refers to the lost		that uses the session ID that refers to the lost
	session.		session.
	</t>		</t>
	<t>		<t>
	After an event like a server restart, the client may have		After an event like a server restart, the client may have
	lost its connections. The client assumes for the moment		lost its connections. The client assumes for the moment
	that the session has not been lost. It reconnects, and		that the session has not been lost. It reconnects, and
	if it specified connection association enforcement when		if it specified connection association enforcement when
	the session was created, it		the session was created, it
	invokes BIND_CONN_TO_SESSION using the session ID. Otherwise,		invokes BIND_CONN_TO_SESSION using the session ID. Otherwise,
	it invokes SEQUENCE. If		it invokes SEQUENCE. If
	BIND_CONN_TO_SESSION or SEQUENCE returns NFS4ERR_BADSESSION, the		BIND_CONN_TO_SESSION or SEQUENCE returns NFS4ERR_BADSESSION, the
	client knows the session is not available to it when communicating		client knows the session is not available to it when communicating
	with that network address. If the connection survives		with that network address. If the connection survives
	session loss, then the next SEQUENCE operation the client		session loss, then the next SEQUENCE operation the client
	sends over the connection will get back NFS4ERR_BADSESSION.		sends over the connection will get back NFS4ERR_BADSESSION.
	The client again knows the session was lost.		The client again knows the session was lost.
	</t>		</t>
	<t>		<t>
	Here is one suggested algorithm for the client when it gets		Here is one suggested algorithm for the client when it gets
	NFS4ERR_BADSESSION. It is not obligatory in that, if a		NFS4ERR_BADSESSION. It is not obligatory in that, if a
	client does not want to take advantage of such features as		client does not want to take advantage of such features as
	trunking, it may omit parts of it. However, it is a useful		trunking, it may omit parts of it. However, it is a useful
	example that draws attention to various possible recovery		example that draws attention to various possible recovery
	issues:		issues:
	<list style="numbers">		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	If the client has other connections to		If the client has other connections to
	other server network addresses		other server network addresses
	associated with the same session, attempt		associated with the same session, attempt
	a COMPOUND with a single operation, SEQUENCE,		a COMPOUND with a single operation, SEQUENCE,
	on each of the other connections.		on each of the other connections.
	</t>		</li>
	<t>		<li>
	If the attempts succeed, the session is still alive,		If the attempts succeed, the session is still alive,
	and this is a strong indicator that the server's		and this is a strong indicator that the server's
	network address has moved.		network address has moved.
	The client might send an EXCHANGE_ID on the		The client might send an EXCHANGE_ID on the
	connection that returned NFS4ERR_BADSESSION		connection that returned NFS4ERR_BADSESSION
	to see if there are opportunities for client ID		to see if there are opportunities for client ID
	trunking (i.e., the same client ID and so_major value		trunking (i.e., the same client ID and so_major_id value
	are		are
	returned). The client might use DNS to see if		returned). The client might use DNS to see if
	the moved network address was replaced with another,		the moved network address was replaced with another,
	so that the performance and availability benefits of		so that the performance and availability benefits of
	session trunking can continue.		session trunking can continue.
	</t>		</li>
	<t>		<li>
	If the SEQUENCE requests fail with NFS4ERR_BADSESSION,		If the SEQUENCE requests fail with NFS4ERR_BADSESSION,
	then the session no longer exists on any of the		then the session no longer exists on any of the
	server network addresses for which the client has connections		server network addresses for which the client has connections
	associated with that session ID. It is possible the		associated with that session ID. It is possible the
	session is still alive and available on other		session is still alive and available on other
	network addresses. The client sends an EXCHANGE_ID		network addresses. The client sends an EXCHANGE_ID
	on all the connections to see if the server owner		on all the connections to see if the server owner
	is still listening on those network addresses.		is still listening on those network addresses.
	If the same server owner is returned but a new		If the same server owner is returned but a new
	client ID is returned, this is a strong		client ID is returned, this is a strong
	skipping to change at line 5290 ¶		skipping to change at line 5236 ¶
	has no other sessions for that client ID.		has no other sessions for that client ID.
	If a different server owner is returned,		If a different server owner is returned,
	the client can use DNS to find		the client can use DNS to find
	other network addresses. If it does not, or if		other network addresses. If it does not, or if
	DNS does not find any other addresses for the server,		DNS does not find any other addresses for the server,
	then the client will be unable to provide NFSv4.1		then the client will be unable to provide NFSv4.1
	service, and fatal errors should be returned		service, and fatal errors should be returned
	to processes that were using the server. If the		to processes that were using the server. If the
	client is using a "mount" paradigm, unmounting		client is using a "mount" paradigm, unmounting
	the server is advised.		the server is advised.
	</t>		</li>
	<t>		<li>
	If the client knows of no other connections associated		If the client knows of no other connections associated
	with the session ID and server network addresses that		with the session ID and server network addresses that
	are, or have been, associated with the session ID,		are, or have been, associated with the session ID,
	then the client can use DNS to find		then the client can use DNS to find
	other network addresses. If it does not, or if		other network addresses. If it does not, or if
	DNS does not find any other addresses for the server,		DNS does not find any other addresses for the server,
	then the client will be unable to provide NFSv4.1		then the client will be unable to provide NFSv4.1
	service, and fatal errors should be returned		service, and fatal errors should be returned
	to processes that were using the server. If the		to processes that were using the server. If the
	client is using a "mount" paradigm, unmounting		client is using a "mount" paradigm, unmounting
	the server is advised.		the server is advised.
	</t>		</li>
	</list>		</ol>
	</t>		<t>
	<t>
	If there is a reconfiguration event that results in the		If there is a reconfiguration event that results in the
	same network address being assigned to servers where the		same network address being assigned to servers where the
	eir_server_scope value is different, it cannot be guaranteed		eir_server_scope value is different, it cannot be guaranteed
	that a session ID generated by the first will be recognized		that a session ID generated by the first will be recognized
	as invalid by the first. Therefore, in managing server		as invalid by the first. Therefore, in managing server
	reconfigurations among servers with different server scope		reconfigurations among servers with different server scope
	values, it is necessary to make sure that all clients have		values, it is necessary to make sure that all clients have
	disconnected from the first server before effecting		disconnected from the first server before effecting
	the reconfiguration. Nonetheless, clients should not		the reconfiguration. Nonetheless, clients should not
	assume that servers will always adhere to this requirement;		assume that servers will always adhere to this requirement;
	clients MUST be prepared to deal with unexpected		clients <bcp14>MUST</bcp14> be prepared to deal with unexpected
	effects of server reconfigurations.		effects of server reconfigurations.
	Even where a session ID is inappropriately		Even where a session ID is inappropriately
	recognized as valid, it is likely either that the connection		recognized as valid, it is likely either that the connection
	will not be recognized as valid or that a sequence value		will not be recognized as valid or that a sequence value
	for a slot will not be correct. Therefore, when a client		for a slot will not be correct. Therefore, when a client
	receives results indicating such unexpected errors, the use of		receives results indicating such unexpected errors, the use of
	EXCHANGE_ID to determine the current server configuration		EXCHANGE_ID to determine the current server configuration
	is RECOMMENDED.		is <bcp14>RECOMMENDED</bcp14>.
	</t>		</t>
	<t>		<t>
	A variation on the above is that after a server's network		A variation on the above is that after a server's network
	address moves, there is no NFSv4.1 server listening, e.g., no		address moves, there is no NFSv4.1 server listening, e.g., no
	listener on port 2049. In this example, one of the following occur: the NF Sv4 server returns		listener on port 2049. In this example, one of the following occur: the NF Sv4 server returns
	NFS4ERR_MINOR_VERS_MISMATCH, the NFS server returns a		NFS4ERR_MINOR_VERS_MISMATCH, the NFS server returns a
	PROG_MISMATCH error, the RPC listener on 2049 returns		PROG_MISMATCH error, the RPC listener on 2049 returns
	PROG_UNVAIL, or attempts to reconnect to the network address		PROG_UNVAIL, or attempts to reconnect to the network address
	timeout. These SHOULD be treated as equivalent to SEQUENCE		timeout. These <bcp14>SHOULD</bcp14> be treated as equivalent to SEQUENCE
	returning NFS4ERR_BADSESSION for these purposes.		returning NFS4ERR_BADSESSION for these purposes.
	</t>		</t>
	<t>		<t>
	When the client detects session loss, it needs to call CREATE_SESSION		When the client detects session loss, it needs to call CREATE_SESSION
	to recover. Any non-idempotent operations that were in progress		to recover. Any non-idempotent operations that were in progress
	might have been performed on the server at the time of		might have been performed on the server at the time of
	session loss. The client has no general way to recover from this.		session loss. The client has no general way to recover from this.
	</t>		</t>
	<t>		<t>
	Note that loss of session does not imply loss of byte-range lock, open, del egation,		Note that loss of session does not imply loss of byte-range lock, open, del egation,
	or layout state because locks, opens, delegations, and layouts		or layout state because locks, opens, delegations, and layouts
	are tied to the client ID and depend on the client ID, not the session.		are tied to the client ID and depend on the client ID, not the session.
	Nor does loss of byte-range lock, open, delegation,		Nor does loss of byte-range lock, open, delegation,
	or layout state imply loss of session state, because the session depends		or layout state imply loss of session state, because the session depends
	on the client ID; loss of client ID however does imply loss of		on the client ID; loss of client ID however does imply loss of
	session, byte-range lock, open, delegation, and layout state.		session, byte-range lock, open, delegation, and layout state.
	See <xref target="server_failure" />.		See <xref target="server_failure" format="default"/>.
	A session can survive a server restart,		A session can survive a server restart,
	but lock recovery may still be needed.		but lock recovery may still be needed.
	</t>		</t>
	<t>		<t>
	It is possible that CREATE_SESSION will fail with NFS4ERR_STALE_CLIENTID		It is possible that CREATE_SESSION will fail with NFS4ERR_STALE_CLIENTID
	(e.g., the server restarts and does not preserve client ID		(e.g., the server restarts and does not preserve client ID
	state).		state).
	If so, the client needs to call EXCHANGE_ID, followed by		If so, the client needs to call EXCHANGE_ID, followed by
	CREATE_SESSION.		CREATE_SESSION.
	</t>		</t>
	</section> <!-- Loss of Session -->		</section>
	</section> <!-- Events Requiring Client Action -->		</section>
	<section anchor="Events_Requiring_Server_Action" title="Events Requiring Serv		<section anchor="Events_Requiring_Server_Action" numbered="true" toc="default
	er Action">		">
	<t>		<name>Events Requiring Server Action</name>
			<t>
	The following events require server action to recover.		The following events require server action to recover.
	</t>		</t>
	<section title="Client Crash and Restart">		<section numbered="true" toc="default">
	<t>		<name>Client Crash and Restart</name>
	As described in <xref target="OP_EXCHANGE_ID" />,		<t>
			As described in <xref target="OP_EXCHANGE_ID" format="default"/>,
	a restarted client sends EXCHANGE_ID in such a way that it		a restarted client sends EXCHANGE_ID in such a way that it
	causes the server to delete any sessions it had.		causes the server to delete any sessions it had.
	</t>		</t>
	</section> <!-- Client Crash and Restart -->		</section>
	<section title="Client Crash with No Restart" anchor="client_crash_no_restar		<section anchor="client_crash_no_restart" numbered="true" toc="default">
	t">		<name>Client Crash with No Restart</name>
	<t>		<t>
	If a client crashes and never comes back, it will never send		If a client crashes and never comes back, it will never send
	EXCHANGE_ID with its old client owner. Thus, the server has session		EXCHANGE_ID with its old client owner. Thus, the server has session
	state that will never be used again. After an extended period of time,		state that will never be used again. After an extended period of time,
	and if the server has resource constraints, it MAY destroy the old		and if the server has resource constraints, it <bcp14>MAY</bcp14> destroy th e old
	session as well as locking state.		session as well as locking state.
	</t>		</t>
	</section> <!-- Client Crash with No Restart -->		</section>
	<section title="Extended Network Partition">		<section numbered="true" toc="default">
	<t>		<name>Extended Network Partition</name>
			<t>
	To the server, the extended network partition may be no		To the server, the extended network partition may be no
	different from a		different from a
	client crash with no		client crash with no
	restart (see		restart (see
	<xref target="client_crash_no_restart" />).		<xref target="client_crash_no_restart" format="default"/>).
	Unless the server can discern that there is		Unless the server can discern that there is
	a network partition, it is free to treat the		a network partition, it is free to treat the
	situation as if the client has crashed permanently.		situation as if the client has crashed permanently.
	</t>		</t>
	</section> <!-- "Extended Network Partition" -->		</section>
	<section title="Backchannel Connection Loss">		<section numbered="true" toc="default">
	<t>		<name>Backchannel Connection Loss</name>
			<t>
	If there were callback requests outstanding at the time		If there were callback requests outstanding at the time
	of a connection loss, then the server		of a connection loss, then the server
	MUST retry the requests, as described in		<bcp14>MUST</bcp14> retry the requests, as described in
	<xref target="Retry_and_Replay" />. Note that it		<xref target="Retry_and_Replay" format="default"/>. Note that it
	is not necessary to retry requests over a connection		is not necessary to retry requests over a connection
	with the same source network address or the same destination		with the same source network address or the same destination
	network address as the lost connection. As long as		network address as the lost connection. As long as
	the session ID, slot ID, and sequence ID in the retry		the session ID, slot ID, and sequence ID in the retry
	match that of the original request, the callback target will		match that of the original request, the callback target will
	recognize the request as a retry even if it did see the request		recognize the request as a retry even if it did see the request
	prior to disconnect.		prior to disconnect.
	</t>		</t>
	<t>		<t>
	If the connection lost is the last one associated with the backchannel,		If the connection lost is the last one associated with the backchannel,
	then the server MUST indicate that in the sr_status_flags field of		then the server <bcp14>MUST</bcp14> indicate that in the sr_status_flags fi eld of
	every SEQUENCE reply until the backchannel is re-established.		every SEQUENCE reply until the backchannel is re-established.
	There are two situations, each of which uses different		There are two situations, each of which uses different
	status flags: no connectivity for the session's backchannel		status flags: no connectivity for the session's backchannel
	and no connectivity for any session backchannel of the client.		and no connectivity for any session backchannel of the client.
	See <xref target="OP_SEQUENCE" /> for a description of		See <xref target="OP_SEQUENCE" format="default"/> for a description of
	the appropriate flags in sr_status_flags.		the appropriate flags in sr_status_flags.
	</t>		</t>
	</section> <!-- Backchannel Connection Loss -->		</section>
	<section title="GSS Context Loss">		<section numbered="true" toc="default">
	<t>		<name>GSS Context Loss</name>
	The server SHOULD monitor when the number of RPCSEC_GSS		<t>
			The server <bcp14>SHOULD</bcp14> monitor when the number of RPCSEC_GSS
	handles assigned to the backchannel reaches one, and when that		handles assigned to the backchannel reaches one, and when that
	one handle is near expiry (i.e., between		one handle is near expiry (i.e., between
	one and two periods of lease time), and		one and two periods of lease time), and
	indicate so in the sr_status_flags field of all SEQUENCE replies.		indicate so in the sr_status_flags field of all SEQUENCE replies.
	The server MUST indicate when all of the		The server <bcp14>MUST</bcp14> indicate when all of the
	backchannel's assigned RPCSEC_GSS handles		backchannel's assigned RPCSEC_GSS handles
	have expired via the sr_status_flags field of all SEQUENCE replies.		have expired via the sr_status_flags field of all SEQUENCE replies.
	</t>		</t>
	</section> <!-- GSS Context Loss -->		</section>
	</section> <!-- Events Requiring Server Action -->		</section>
	</section> <!-- Session Mechanics - Recovery -->		</section>
	<section title="Parallel NFS and Sessions" anchor="pnfs_and_sessions">		<section anchor="pnfs_and_sessions" numbered="true" toc="default">
	<t>		<name>Parallel NFS and Sessions</name>
			<t>
	A client and server can potentially be a non-pNFS implementation,		A client and server can potentially be a non-pNFS implementation,
	a metadata server implementation, a data server implementation, or two or		a metadata server implementation, a data server implementation, or two or
	three types of implementations. The EXCHGID4_FLAG_USE_NON_PNFS,		three types of implementations. The EXCHGID4_FLAG_USE_NON_PNFS,
	EXCHGID4_FLAG_USE_PNFS_MDS, and EXCHGID4_FLAG_USE_PNFS_DS flags		EXCHGID4_FLAG_USE_PNFS_MDS, and EXCHGID4_FLAG_USE_PNFS_DS flags
	(not mutually exclusive) are passed in the EXCHANGE_ID arguments		(not mutually exclusive) are passed in the EXCHANGE_ID arguments
	and results to allow the client to indicate how it wants to use sessions crea ted		and results to allow the client to indicate how it wants to use sessions crea ted
	under the client ID, and to allow the server to indicate how it		under the client ID, and to allow the server to indicate how it
	will allow the sessions to be used.		will allow the sessions to be used.
	See <xref target="pnfs_session_stuff" /> for pNFS sessions considerations.		See <xref target="pnfs_session_stuff" format="default"/> for pNFS sessions co
	</t>		nsiderations.
	</section> <!-- Parallel NFS and Sessions -->		</t>
	</section> <!-- Session -->		</section>
	</section> <!-- Core Infrastructure -->		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		</section>
	$ -->		<section numbered="true" toc="default">
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<name>Protocol Constants and Data Types</name>
	<!-- Copyright (C) The Internet Society (2006) -->		<t>
	<section title="Protocol Constants and Data Types">
	<t>
	The syntax and semantics to describe the data types of the NFSv4.1		The syntax and semantics to describe the data types of the NFSv4.1
	protocol are defined in the XDR <xref target="RFC4506">RFC 4506</xref> and R		protocol are defined in the XDR (<xref target="RFC4506" format="default">RFC
	PC		4506</xref>) and RPC
	<xref target="RFC5531">RFC 5531</xref> documents. The next sections		(<xref target="RFC5531" format="default">RFC 5531</xref>) documents. The ne
			xt sections
	build upon the XDR data types to define constants, types, and structures		build upon the XDR data types to define constants, types, and structures
	specific to this protocol. The full list of XDR data types is in <xref targe		specific to this protocol. The full list of XDR data types is in <xref targe
	t="RFC5662" />.		t="RFC5662" format="default"/>.
	</t>		</t>
			<section numbered="true" toc="default">
	<section title="Basic Constants">		<name>Basic Constants</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	const NFS4_FHSIZE = 128;		const NFS4_FHSIZE = 128;
	const NFS4_VERIFIER_SIZE = 8;		const NFS4_VERIFIER_SIZE = 8;
	const NFS4_OPAQUE_LIMIT = 1024;		const NFS4_OPAQUE_LIMIT = 1024;
	const NFS4_SESSIONID_SIZE = 16;		const NFS4_SESSIONID_SIZE = 16;
	const NFS4_INT64_MAX = 0x7fffffffffffffff;		const NFS4_INT64_MAX = 0x7fffffffffffffff;
	const NFS4_UINT64_MAX = 0xffffffffffffffff;		const NFS4_UINT64_MAX = 0xffffffffffffffff;
	const NFS4_INT32_MAX = 0x7fffffff;		const NFS4_INT32_MAX = 0x7fffffff;
	const NFS4_UINT32_MAX = 0xffffffff;		const NFS4_UINT32_MAX = 0xffffffff;
	const NFS4_MAXFILELEN = 0xffffffffffffffff;		const NFS4_MAXFILELEN = 0xffffffffffffffff;
	const NFS4_MAXFILEOFF = 0xfffffffffffffffe;		const NFS4_MAXFILEOFF = 0xfffffffffffffffe;
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	Except where noted, all these constants are defined in bytes.		Except where noted, all these constants are defined in bytes.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	NFS4_FHSIZE is the maximum size of a filehandle.		NFS4_FHSIZE is the maximum size of a filehandle.
	</t>		</li>
	<t>		<li>
	NFS4_VERIFIER_SIZE is the fixed size of a verifier.		NFS4_VERIFIER_SIZE is the fixed size of a verifier.
	</t>		</li>
	<t>		<li>
	NFS4_OPAQUE_LIMIT is the maximum size of certain		NFS4_OPAQUE_LIMIT is the maximum size of certain
	opaque information.		opaque information.
	</t>		</li>
	<t>		<li>
	NFS4_SESSIONID_SIZE is the fixed size of a session identifier.		NFS4_SESSIONID_SIZE is the fixed size of a session identifier.
	</t>		</li>
	<t>		<li>
	NFS4_INT64_MAX is the maximum value of a signed 64-bit integer.		NFS4_INT64_MAX is the maximum value of a signed 64-bit integer.
	</t>		</li>
	<t>		<li>
	NFS4_UINT64_MAX is the maximum value of an unsigned 64-bit integer.		NFS4_UINT64_MAX is the maximum value of an unsigned 64-bit integer.
	</t>		</li>
	<t>		<li>
	NFS4_INT32_MAX is the maximum value of a signed 32-bit integer.		NFS4_INT32_MAX is the maximum value of a signed 32-bit integer.
	</t>		</li>
	<t>		<li>
	NFS4_UINT32_MAX is the maximum value of an unsigned 32-bit integer.		NFS4_UINT32_MAX is the maximum value of an unsigned 32-bit integer.
	</t>		</li>
	<t>		<li>
	NFS4_MAXFILELEN is the maximum length of a regular file.		NFS4_MAXFILELEN is the maximum length of a regular file.
	</t>		</li>
	<t>		<li>
	NFS4_MAXFILEOFF is the maximum offset into a regular file.		NFS4_MAXFILEOFF is the maximum offset into a regular file.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section numbered="true" toc="default">
			<name>Basic Data Types</name>
	<section title="Basic Data Types">		<t>
	<t>
	These are the base NFSv4.1 data types.		These are the base NFSv4.1 data types.
	</t>		</t>
	<texttable anchor='basic_data_types'>		<table anchor="basic_data_types" align="center">
			<thead>
	<ttcol align='left'>Data Type</ttcol>		<tr>
	<ttcol align='left'>Definition</ttcol>		<th align="left">Data Type</th>
	<c>int32_t</c> <c>typedef int int32_t;</c>		<th align="left">Definition</th>
			</tr>
	<c>uint32_t</c> <c>typedef unsigned int uint32_t;</c>		</thead>
			<tbody>
	<c>int64_t</c> <c>typedef hyper int64_t;</c>		<tr>
			<td align="left">int32_t</td>
	<c>uint64_t</c> <c>typedef unsigned hyper uint64_t;</c>		<td align="left">typedef int int32_t;</td>
			</tr>
	<c>attrlist4</c> <c>typedef opaque attrlist4&lt;>;</c>		<tr>
	<c/> <c>Used for file/directory attributes.</c>		<td align="left">uint32_t</td>
			<td align="left">typedef unsigned int uint32_t;</td>
	<c>bitmap4</c> <c>typedef uint32_t bitmap4&lt;>;</c>		</tr>
	<c/> <c>Used in attribute array encoding.</c>		<tr>
			<td align="left">int64_t</td>
	<c>changeid4</c> <c>typedef uint64_t changeid4;</c>		<td align="left">typedef hyper int64_t;</td>
	<c/> <c>Used in the definition of change_info4.</c>		</tr>
			<tr>
	<c>clientid4</c> <c>typedef uint64_t clientid4;</c>		<td align="left">uint64_t</td>
	<c/> <c>Shorthand reference to client identification.</c>		<td align="left">typedef unsigned hyper uint64_t;</td>
			</tr>
	<c>count4</c> <c>typedef uint32_t count4;</c>		<tr>
	<c/> <c>Various count parameters (READ, WRITE, COMMIT).</c>		<td align="left">attrlist4</td>
			<td align="left"><t>typedef opaque attrlist4&lt;&gt;;</t>
	<c>length4</c> <c>typedef uint64_t length4;</c>		<t>Used for file/directory attributes.</t></td>
	<c/> <c>The length of a byte-range within a file.</c>		</tr>
			<tr>
	<c>mode4</c> <c>typedef uint32_t mode4;</c>		<td align="left">bitmap4</td>
	<c/> <c>Mode attribute data type.</c>		<td align="left"><t>typedef uint32_t bitmap4&lt;&gt;;</t>
			<t>Used in attribute array encoding.</t>
	<c>nfs_cookie4</c> <c>typedef uint64_t nfs_cookie4;</c>		</td>
	<c/> <c>Opaque cookie value for READDIR.</c>		</tr>
			<tr>
	<c>nfs_fh4</c> <c>typedef opaque nfs_fh4&lt;NFS4_FHSIZE>;</c>		<td align="left">changeid4</td>
	<c/> <c>Filehandle definition.</c>		<td align="left"><t>typedef uint64_t changeid4;</t>
			<t>Used in the definition of change_info4.</t>
	<c>nfs_ftype4</c> <c>enum nfs_ftype4;</c>		</td>
	<c/> <c>Various defined file types.</c>		</tr>
			<tr>
	<c>nfsstat4</c> <c>enum nfsstat4;</c>		<td align="left">clientid4</td>
	<c/> <c>Return value for operations.</c>		<td align="left"><t>typedef uint64_t clientid4;</t>
			<t>Shorthand reference to client identification.</t>
	<c>offset4</c> <c>typedef uint64_t offset4;</c>		</td>
	<c/> <c>Various offset designations (READ, WRITE, LOCK, COMMIT).</c>		</tr>
			<tr>
	<c>qop4</c> <c>typedef uint32_t qop4;</c>		<td align="left">count4</td>
	<c/> <c>Quality of protection designation in SECINFO.</c>		<td align="left"><t>typedef uint32_t count4;</t>
			<t>Various count parameters (READ, WRITE,
	<c>sec_oid4</c> <c>typedef opaque sec_oid4&lt;>;</c>		COMMIT).</t>
	<c/> <c>Security Object Identifier. The sec_oid4 data type is not rea		</td>
	lly opaque. Instead, it contains an ASN.1 OBJECT IDENTIFIER as used by GSS-API		</tr>
	in the mech_type argument to GSS_Init_sec_context. See <xref target="RFC2743" />		<tr>
	for details.</c>		<td align="left">length4</td>
			<td align="left"><t>typedef uint64_t length4;</t>
	<c>sequenceid4</c> <c>typedef uint32_t sequenceid4;</c>		<t>The length of a byte-range within a file.</t>
	<c/> <c>Sequence number used for various session operations (EXCHANGE_		</td>
	ID, CREATE_SESSION, SEQUENCE, CB_SEQUENCE).</c>		</tr>
			<tr>
	<c>seqid4</c> <c>typedef uint32_t seqid4;</c>		<td align="left">mode4</td>
	<c/> <c>Sequence identifier used for locking.</c>		<td align="left"><t>typedef uint32_t mode4;</t>
			<t>Mode attribute data type.</t>
	<c>sessionid4</c> <c>typedef opaque sessionid4[NFS4_SESSION		</td>
	ID_SIZE];</c>		</tr>
	<c/> <c>Session identifier.</c>		<tr>
			<td align="left">nfs_cookie4</td>
	<c>slotid4</c> <c>typedef uint32_t slotid4;</c>		<td align="left"><t>typedef uint64_t nfs_cookie4;</t>
	<c/> <c>Sequencing artifact for various session operations (SEQUENCE,		<t>Opaque cookie value for READDIR.</t>
	CB_SEQUENCE).</c>		</td>
			</tr>
	<c>utf8string</c> <c>typedef opaque utf8string&lt;>;</c>		<tr>
	<c/> <c>UTF-8 encoding for strings.</c>		<td align="left">nfs_fh4</td>
			<td align="left"><t>typedef opaque nfs_fh4&lt;NFS4_FHSIZE&gt;;</t>
	<c>utf8str_cis</c> <c>typedef utf8string utf8str_cis;</c>		<t>Filehandle definition.</t>
	<c/> <c>Case-insensitive UTF-8 string.</c>		</td>
			</tr>
	<c>utf8str_cs</c> <c>typedef utf8string utf8str_cs;</c>		<tr>
	<c/> <c>Case-sensitive UTF-8 string.</c>		<td align="left">nfs_ftype4</td>
			<td align="left"><t>enum nfs_ftype4;</t>
	<c>utf8str_mixed</c> <c>typedef utf8string utf8str_mixed;</c>		<t>Various defined file types.</t>
	<c/> <c>UTF-8 strings with a case-sensitive prefix and a		</td>
	case-insensitive suffix.</c>		</tr>
			<tr>
	<c>component4</c> <c>typedef utf8str_cs component4;</c>		<td align="left">nfsstat4</td>
	<c/> <c>Represents pathname components.</c>		<td align="left"><t>enum nfsstat4;</t>
			<t>Return value for operations.</t>
	<c>linktext4</c> <c>typedef utf8str_cs linktext4;</c>		</td>
	<c/> <c>Symbolic link contents ("symbolic link" is defined in an <xref		</tr>
	target="symlink">Open Group</xref> standard).</c>		<tr>
			<td align="left">offset4</td>
	<c>pathname4</c> <c>typedef component4 pathname4&lt;>;</c>		<td align="left"><t>typedef uint64_t offset4;</t>
	<c/> <c>Represents pathname for fs_locations.</c>		<t>Various offset designations (READ, WRITE, LOCK, COMMIT).</t>
			</td>
	<c>verifier4</c> <c>typedef opaque verifier4[NFS4_VERIFIER		</tr>
	_SIZE];</c>		<tr>
	<c/> <c>Verifier used for various operations (COMMIT, CREATE, EXCHANGE		<td align="left">qop4</td>
	_ID, OPEN, READDIR, WRITE) NFS4_VERIFIER_SIZE is defined as 8.</c>		<td align="left"><t>typedef uint32_t qop4;</t>
			<t>Quality of protection designation in SECINFO.</t>
	<postamble>End of Base Data Types</postamble>		</td>
	</texttable>		</tr>
	</section>		<tr>
			<td align="left">sec_oid4</td>
	<!-- start here for the structured data types -->		<td align="left"><t>typedef opaque sec_oid4&lt;&gt;;</t>
			<t>Security Object Identifier. The sec_oid4 data type is not
	<section title="Structured Data Types">		really opaque. Instead, it contains an ASN.1 OBJECT IDENTIFIER
			as used by GSS-API in the mech_type argument to
			GSS_Init_sec_context. See <xref target="RFC2743"
			format="default"/> for details.</t>
			</td>
			</tr>
			<tr>
			<td align="left">sequenceid4</td>
			<td align="left"><t>typedef uint32_t sequenceid4;</t>
			<t>Sequence number used for various session operations
			(EXCHANGE_ID, CREATE_SESSION, SEQUENCE, CB_SEQUENCE).</t>
			</td>
			</tr>
			<tr>
			<td align="left">seqid4</td>
			<td align="left"><t>typedef uint32_t seqid4;</t>
			<t>Sequence identifier used for locking.</t>
			</td>
			</tr>
			<tr>
			<td align="left">sessionid4</td>
			<td align="left"><t>typedef opaque sessionid4[NFS4_SESSIONID_SIZE]
			;</t>
			<t>Session identifier.</t>
			</td>
			</tr>
			<tr>
			<td align="left">slotid4</td>
			<td align="left"><t>typedef uint32_t slotid4;</t>
			<t>Sequencing artifact for various session operations
			(SEQUENCE, CB_SEQUENCE).</t>
			</td>
			</tr>
			<tr>
			<td align="left">utf8string</td>
			<td align="left"><t>typedef opaque utf8string&lt;&gt;;</t>
			<t>UTF-8 encoding for strings.</t>
			</td>
			</tr>
			<tr>
			<td align="left">utf8str_cis</td>
			<td align="left"><t>typedef utf8string utf8str_cis;</t>
			<t>Case-insensitive UTF-8 string.</t>
			</td>
			</tr>
			<tr>
			<td align="left">utf8str_cs</td>
			<td align="left"><t>typedef utf8string utf8str_cs;</t>
			<t>Case-sensitive UTF-8 string.</t>
			</td>
			</tr>
			<tr>
			<td align="left">utf8str_mixed</td>
			<td align="left"><t>typedef utf8string utf8str_mixed;</t>
			<t>UTF-8 strings with a case-sensitive prefix and a
			case-insensitive suffix.</t>
			</td>
			</tr>
			<tr>
			<td align="left">component4</td>
			<td align="left"><t>typedef utf8str_cs component4;</t>
			<t>Represents pathname components.</t>
			</td>
			</tr>
			<tr>
			<td align="left">linktext4</td>
			<td align="left"><t>typedef utf8str_cs linktext4;</t>
			<t>Symbolic link contents ("symbolic link" is defined in an
			<xref target="symlink" format="default">Open Group</xref>
			standard).</t>
			</td>
			</tr>
			<tr>
			<td align="left">pathname4</td>
			<td align="left"><t>typedef component4 pathname4&lt;&gt;;</t>
			<t>Represents pathname for fs_locations.</t>
			</td>
			</tr>
			<tr>
			<td align="left">verifier4</td>
			<td align="left"><t>typedef opaque verifier4[NFS4_VERIFIER_SIZE];<
			/t>
			<t>Verifier used for various operations (COMMIT, CREATE,
			EXCHANGE_ID, OPEN, READDIR, WRITE) NFS4_VERIFIER_SIZE is defined
			as 8.</t>
			</td>
			</tr>
			</tbody>
			</table>
			<t>End of Base Data Types</t>
			</section>
	<section toc="exclude" anchor="nfstime4" title="nfstime4">		<section numbered="true" toc="default">
	<figure>		<name>Structured Data Types</name>
	<artwork>		<section toc="exclude" anchor="nfstime4" numbered="true">
			<name>nfstime4</name>
			<sourcecode type="xdr"><![CDATA[
	struct nfstime4 {		struct nfstime4 {
	int64_t seconds;		int64_t seconds;
	uint32_t nseconds;		uint32_t nseconds;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The nfstime4 data type gives the number of seconds and		The nfstime4 data type gives the number of seconds and
	nanoseconds since midnight or zero hour January 1, 1970		nanoseconds since midnight or zero hour January 1, 1970
	Coordinated Universal Time (UTC). Values greater than zero		Coordinated Universal Time (UTC). Values greater than zero
	for the seconds field denote dates after the zero hour January 1,		for the seconds field denote dates after the zero hour January 1,
	1970. Values less than zero for the seconds field denote		1970. Values less than zero for the seconds field denote
	dates before the zero hour January 1, 1970. In both cases, the		dates before the zero hour January 1, 1970. In both cases, the
	nseconds field is to be added to the seconds field for the		nseconds field is to be added to the seconds field for the
	final time representation. For example, if the time to be		final time representation. For example, if the time to be
	represented is one-half second before zero hour January 1, 1970,		represented is one-half second before zero hour January 1, 1970,
	the seconds field would have a value of negative one (-1) and		the seconds field would have a value of negative one (-1) and
	the nseconds field would have a value of one-half second		the nseconds field would have a value of one-half second
	(500000000). Values greater than 999,999,999 for nseconds are		(500000000). Values greater than 999,999,999 for nseconds are
	invalid.		invalid.
	</t>		</t>
	<t>		<t>
	This data type is used to pass time and date information. A		This data type is used to pass time and date information. A
	server converts to and from its local representation of time		server converts to and from its local representation of time
	when processing time values, preserving as much accuracy as		when processing time values, preserving as much accuracy as
	possible. If the precision of timestamps stored for a		possible. If the precision of timestamps stored for a
	file system object is less than defined, loss of precision can		file system object is less than defined, loss of precision can
	occur. An adjunct time maintenance protocol is RECOMMENDED to		occur. An adjunct time maintenance protocol is <bcp14>RECOMMENDED</bcp14 > to
	reduce client and server time skew.		reduce client and server time skew.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="time_how4" numbered="true">
	<section toc="exclude" anchor="time_how4" title="time_how4">		<name>time_how4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	enum time_how4 {		enum time_how4 {
	SET_TO_SERVER_TIME4 = 0,		SET_TO_SERVER_TIME4 = 0,
	SET_TO_CLIENT_TIME4 = 1		SET_TO_CLIENT_TIME4 = 1
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="settime4" numbered="true">
			<name>settime4</name>
	<section toc="exclude" anchor="settime4" title="settime4">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	union settime4 switch (time_how4 set_it) {		union settime4 switch (time_how4 set_it) {
	case SET_TO_CLIENT_TIME4:		case SET_TO_CLIENT_TIME4:
	nfstime4 time;		nfstime4 time;
	default:		default:
	void;		void;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The time_how4 and settime4 data types are used		The time_how4 and settime4 data types are used
	for setting timestamps in file object attributes. If set_it is SET_TO_SE RVER_TIME4, then the server		for setting timestamps in file object attributes. If set_it is SET_TO_SE RVER_TIME4, then the server
	uses its local representation of time for the time value.		uses its local representation of time for the time value.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="specdata4" numbered="true">
	<section toc="exclude" anchor="specdata4" title="specdata4">		<name>specdata4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct specdata4 {		struct specdata4 {
	uint32_t specdata1; /* major device number */		uint32_t specdata1; /* major device number */
	uint32_t specdata2; /* minor device number */		uint32_t specdata2; /* minor device number */
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	This data type represents the device numbers for the device file		This data type represents the device numbers for the device file
	types NF4CHR and NF4BLK.		types NF4CHR and NF4BLK.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="fsid4" numbered="true">
	<section toc="exclude" anchor="fsid4" title="fsid4">		<name>fsid4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct fsid4 {		struct fsid4 {
	uint64_t major;		uint64_t major;
	uint64_t minor;		uint64_t minor;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="chg_policy4" numbered="true">
			<name>change_policy4</name>
	<section toc="exclude" anchor="chg_policy4" title="change_policy4">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct change_policy4 {		struct change_policy4 {
	uint64_t cp_major;		uint64_t cp_major;
	uint64_t cp_minor;		uint64_t cp_minor;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The change_policy4 data type is used for the change_policy		The change_policy4 data type is used for the change_policy
	RECOMMENDED attribute. It provides change sequencing indication		<bcp14>RECOMMENDED</bcp14> attribute. It provides change sequencing in dication
	analogous to the change attribute. To enable the server to		analogous to the change attribute. To enable the server to
	present a value valid across server re-initialization without		present a value valid across server re-initialization without
	requiring persistent storage, two 64-bit quantities are used,		requiring persistent storage, two 64-bit quantities are used,
	allowing one to be a server instance ID and the second to be		allowing one to be a server instance ID and the second to be
	incremented non-persistently, within a given server instance.		incremented non-persistently, within a given server instance.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="fattr4" numbered="true">
	<section toc="exclude" anchor="fattr4" title="fattr4">		<name>fattr4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct fattr4 {		struct fattr4 {
	bitmap4 attrmask;		bitmap4 attrmask;
	attrlist4 attr_vals;		attrlist4 attr_vals;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The fattr4 data type is used to represent file and directory attributes.		The fattr4 data type is used to represent file and directory attributes.
	</t>		</t>
	<t>		<t>
	The bitmap is a counted array of 32-bit integers used to contain bit		The bitmap is a counted array of 32-bit integers used to contain bit
	values. The position of the integer in the array that contains bit n		values. The position of the integer in the array that contains bit n
	can be computed from the expression (n / 32), and its bit within that		can be computed from the expression (n / 32), and its bit within that
	integer is (n mod 32).		integer is (n mod 32).
	</t>		</t>
	<t>
	<figure>		<artwork name="" type="" align="left" alt=""><![CDATA[
	<artwork>		0 1
	0 1
	+-----------+-----------+-----------+--		+-----------+-----------+-----------+--
	| count | 31 .. 0 | 63 .. 32 |		| count | 31 .. 0 | 63 .. 32 |
	+-----------+-----------+-----------+--		+-----------+-----------+-----------+--
	</artwork>		]]></artwork>
	</figure>		</section>
	</t>		<section toc="exclude" anchor="change_info4" numbered="true">
	</section>		<name>change_info4</name>
			<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="change_info4" title="change_info4">
	<figure>
	<artwork>
	struct change_info4 {		struct change_info4 {
	bool atomic;		bool atomic;
	changeid4 before;		changeid4 before;
	changeid4 after;		changeid4 after;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	This data type is used with the CREATE, LINK, OPEN, REMOVE, and RENAME		This data type is used with the CREATE, LINK, OPEN, REMOVE, and RENAME
	operations to let the client know the value of the change attribute		operations to let the client know the value of the change attribute
	for the directory in which the target file system object resides.		for the directory in which the target file system object resides.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="netaddr4" numbered="true">
	<section toc="exclude" anchor="netaddr4" title="netaddr4">		<name>netaddr4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct netaddr4 {		struct netaddr4 {
	/* see struct rpcb in RFC 1833 */		/* see struct rpcb in RFC 1833 */
	string na_r_netid&lt;>; /* network id */		string na_r_netid<>; /* network id */
	string na_r_addr&lt;>; /* universal address */		string na_r_addr<>; /* universal address */
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The netaddr4 data type is used to identify network transport endpoints.		The netaddr4 data type is used to identify network transport endpoints.
	The na_r_netid and na_r_addr fields respectively contain a netid		The na_r_netid and na_r_addr fields respectively contain a netid
	and uaddr. The netid and uaddr concepts are defined in		and uaddr. The netid and uaddr concepts are defined in
	<xref target="RFC5665"/>. The netid and uaddr formats for		<xref target="RFC5665" format="default"/>. The netid and uaddr formats fo
	TCP over IPv4 and TCP over IPv6 are defined in <xref target="RFC5665"/>,		r
	specifically Tables 2 and 3 and Sections 5.2.3.3 and 5.2.3.4.		TCP over IPv4 and TCP over IPv6 are defined in <xref target="RFC5665" fo
	</t>		rmat="default"/>,
			specifically Tables 2 and 3 and in
	</section>		Sections <xref target="RFC5665" section="5.2.3.3" sectionFormat="bare"/>
			and <xref target="RFC5665" section="5.2.3.4" sectionFormat="bare"/>.
	<section toc="exclude" anchor="state_owner4" title="state_owner4">		</t>
	<figure>		</section>
	<artwork>		<section toc="exclude" anchor="state_owner4" numbered="true">
			<name>state_owner4</name>
			<sourcecode type="xdr"><![CDATA[
	struct state_owner4 {		struct state_owner4 {
	clientid4 clientid;		clientid4 clientid;
	opaque owner&lt;NFS4_OPAQUE_LIMIT>;		opaque owner<NFS4_OPAQUE_LIMIT>;
	};		};
	typedef state_owner4 open_owner4;		typedef state_owner4 open_owner4;
	typedef state_owner4 lock_owner4;		typedef state_owner4 lock_owner4;
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The state_owner4 data type is the base type for the		The state_owner4 data type is the base type for the
	open_owner4 (<xref target="open_owner4" />) and		open_owner4 (<xref target="open_owner4" format="default"/>) and
	lock_owner4 (<xref target="lock_owner4" />).		lock_owner4 (<xref target="lock_owner4" format="default"/>).
	</t>		</t>
			<section toc="exclude" anchor="open_owner4" numbered="true">
	<section toc="exclude" anchor="open_owner4" title="open_owner4">		<name>open_owner4</name>
	<t>		<t>
	This data type is used to identify the owner of OPEN state.		This data type is used to identify the owner of OPEN state.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="lock_owner4" numbered="true">
	<section toc="exclude" anchor="lock_owner4" title="lock_owner4">		<name>lock_owner4</name>
	<t>		<t>
	This structure is used to identify the owner of byte-range		This structure is used to identify the owner of byte-range
	locking state.		locking state.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section toc="exclude" anchor="open_to_lock_owner4" numbered="true">
	<section toc="exclude" anchor="open_to_lock_owner4"		<name>open_to_lock_owner4</name>
	title="open_to_lock_owner4">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct open_to_lock_owner4 {		struct open_to_lock_owner4 {
	seqid4 open_seqid;		seqid4 open_seqid;
	stateid4 open_stateid;		stateid4 open_stateid;
	seqid4 lock_seqid;		seqid4 lock_seqid;
	lock_owner4 lock_owner;		lock_owner4 lock_owner;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	This data type is used for the first LOCK operation done for		This data type is used for the first LOCK operation done for
	an open_owner4. It provides both the open_stateid and		an open_owner4. It provides both the open_stateid and
	lock_owner, such that the transition is made from a valid		lock_owner, such that the transition is made from a valid
	open_stateid sequence to that of the new lock_stateid		open_stateid sequence to that of the new lock_stateid
	sequence. Using this mechanism avoids the confirmation of the		sequence. Using this mechanism avoids the confirmation of the
	lock_owner/lock_seqid pair since it is tied to established		lock_owner/lock_seqid pair since it is tied to established
	state in the form of the open_stateid/open_seqid.		state in the form of the open_stateid/open_seqid.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="stateid4" numbered="true">
	<section toc="exclude" anchor="stateid4" title="stateid4">		<name>stateid4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct stateid4 {		struct stateid4 {
	uint32_t seqid;		uint32_t seqid;
	opaque other[12];		opaque other[12];
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	This data type is used for the various state sharing		This data type is used for the various state sharing
	mechanisms between the client and server. The client		mechanisms between the client and server. The client
	never modifies a value of data type stateid.		never modifies a value of data type stateid.
	The starting value of the		The starting value of the
	"seqid" field is undefined. The server is required to		"seqid" field is undefined. The server is required to
	increment the "seqid" field by one at each transition		increment the "seqid" field by one at each transition
	of the stateid. This is important since the client will		of the stateid. This is important since the client will
	inspect the seqid in OPEN stateids to determine the order of		inspect the seqid in OPEN stateids to determine the order of
	OPEN processing done by the server.		OPEN processing done by the server.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="layouttype4" numbered="true">
	<section toc="exclude" anchor="layouttype4" title="layouttype4">		<name>layouttype4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	enum layouttype4 {		enum layouttype4 {
	LAYOUT4_NFSV4_1_FILES = 0x1,		LAYOUT4_NFSV4_1_FILES = 0x1,
	LAYOUT4_OSD2_OBJECTS = 0x2,		LAYOUT4_OSD2_OBJECTS = 0x2,
	LAYOUT4_BLOCK_VOLUME = 0x3		LAYOUT4_BLOCK_VOLUME = 0x3
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	This data type indicates what type of layout is being used.		This data type indicates what type of layout is being used.
	The file server advertises the		The file server advertises the
	layout types it supports through the fs_layout_type file		layout types it supports through the fs_layout_type file
	system attribute (<xref target="attrdef_fs_layout_type" />).		system attribute (<xref target="attrdef_fs_layout_type" format="default"/ >).
	A client asks for layouts of a particular type in LAYOUTGET,		A client asks for layouts of a particular type in LAYOUTGET,
	and processes those layouts in its layout-type-specific logic.		and processes those layouts in its layout-type-specific logic.
	</t>		</t>
	<t>		<t>
	The layouttype4 data type is 32 bits in length. The range		The layouttype4 data type is 32 bits in length. The range
	represented by the layout type is split into three parts. Type		represented by the layout type is split into three parts. Type
	0x0 is reserved. Types		0x0 is reserved. Types
	within the range 0x00000001-0x7FFFFFFF are globally unique and		within the range 0x00000001-0x7FFFFFFF are globally unique and
	are assigned according to the description in <xref		are assigned according to the description in <xref target="pnfsiana" form
	target="pnfsiana" />; they are maintained by IANA. Types		at="default"/>; they are maintained by IANA. Types
	within the range 0x80000000-0xFFFFFFFF are site specific and		within the range 0x80000000-0xFFFFFFFF are site specific and
	for private use only.		for private use only.
	</t>		</t>
	<t>		<t>
	The LAYOUT4_NFSV4_1_FILES enumeration specifies that the NFSv4.1		The LAYOUT4_NFSV4_1_FILES enumeration specifies that the NFSv4.1
	file layout type, as defined in <xref target="file_layout_type" />, is to be used. The LAYOUT4_OSD2_OBJECTS		file layout type, as defined in <xref target="file_layout_type" format="d efault"/>, is to be used. The LAYOUT4_OSD2_OBJECTS
	enumeration specifies that the object layout, as defined in		enumeration specifies that the object layout, as defined in
	<xref target="RFC5664" />, is to be used. Similarly,		<xref target="RFC5664" format="default"/>, is to be used. Similarly,
	the LAYOUT4_BLOCK_VOLUME enumeration specifies that the block/volume		the LAYOUT4_BLOCK_VOLUME enumeration specifies that the block/volume
	layout, as defined in <xref target="RFC5663" />, is to be		layout, as defined in <xref target="RFC5663" format="default"/>, is to be
	used.		used.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="deviceid4" numbered="true">
	<section toc="exclude" anchor="deviceid4" title="deviceid4">		<name>deviceid4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	const NFS4_DEVICEID4_SIZE = 16;		const NFS4_DEVICEID4_SIZE = 16;
	typedef opaque deviceid4[NFS4_DEVICEID4_SIZE];		typedef opaque deviceid4[NFS4_DEVICEID4_SIZE];
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	Layout information includes device IDs that		Layout information includes device IDs that
	specify a storage device through a compact handle.		specify a storage device through a compact handle.
	Addressing and type information is obtained		Addressing and type information is obtained
	with the GETDEVICEINFO operation. Device IDs		with the GETDEVICEINFO operation. Device IDs
	are not guaranteed to be valid across metadata		are not guaranteed to be valid across metadata
	server restarts. A device ID is unique per client		server restarts. A device ID is unique per client
	ID and layout type. See <xref target="device_ids"		ID and layout type. See <xref target="device_ids" format="default"/> for
	/> for more details.		more details.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="device_addr4"		<section toc="exclude" anchor="device_addr4" numbered="true">
	title="device_addr4">		<name>device_addr4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct device_addr4 {		struct device_addr4 {
	layouttype4 da_layout_type;		layouttype4 da_layout_type;
	opaque da_addr_body&lt;>;		opaque da_addr_body<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The device address is used to set up a communication channel		The device address is used to set up a communication channel
	with the storage device. Different layout types will require		with the storage device. Different layout types will require
	different data types to define how they communicate		different data types to define how they communicate
	with storage devices. The opaque da_addr_body field is		with storage devices. The opaque da_addr_body field is
	interpreted based on the specified da_layout_type field.		interpreted based on the specified da_layout_type field.
	</t>		</t>
	<t>		<t>
	This document defines the device address for the NFSv4.1 file		This document defines the device address for the NFSv4.1 file
	layout (see <xref target="file_data_types" />), which		layout (see <xref target="file_data_types" format="default"/>), which
	identifies a storage device by network IP address and port		identifies a storage device by network IP address and port
	number. This is sufficient for the clients to communicate		number. This is sufficient for the clients to communicate
	with the NFSv4.1 storage devices, and may be sufficient for		with the NFSv4.1 storage devices, and may be sufficient for
	other layout types as well. Device types for object-based storage		other layout types as well. Device types for object-based storage
	devices and block storage devices (e.g., Small Computer System		devices and block storage devices (e.g., Small Computer System
	Interface (SCSI) volume labels)		Interface (SCSI) volume labels)
	are defined by their respective layout specifications.		are defined by their respective layout specifications.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="layout_content4" numbered="true">
	<section toc="exclude" anchor="layout_content4" title="layout_content4">		<name>layout_content4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct layout_content4 {		struct layout_content4 {
	layouttype4 loc_type;		layouttype4 loc_type;
	opaque loc_body&lt;>;		opaque loc_body<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The loc_body field is interpreted based on the layout type (loc_type).		The loc_body field is interpreted based on the layout type (loc_type).
	This document defines the loc_body for the NFSv4.1		This document defines the loc_body for the NFSv4.1
	file layout type; see <xref target="file_data_types"		file layout type; see <xref target="file_data_types" format="default"/> f
	/> for its definition.		or its definition.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="layout4" title="layout4">		<section toc="exclude" anchor="layout4" numbered="true">
	<figure>		<name>layout4</name>
	<artwork>		<sourcecode type="xdr"><![CDATA[
	struct layout4 {		struct layout4 {
	offset4 lo_offset;		offset4 lo_offset;
	length4 lo_length;		length4 lo_length;
	layoutiomode4 lo_iomode;		layoutiomode4 lo_iomode;
	layout_content4 lo_content;		layout_content4 lo_content;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The layout4 data type defines a layout for a file. The layout		The layout4 data type defines a layout for a file. The layout
	type specific data is opaque within lo_content.		type specific data is opaque within lo_content.
	Since layouts are sub-dividable, the offset		Since layouts are sub-dividable, the offset
	and length together with the file's filehandle, the client ID,		and length together with the file's filehandle, the client ID,
	iomode, and layout type identify the layout.		iomode, and layout type identify the layout.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="layoutupdate4" numbered="true">
	<section toc="exclude" anchor="layoutupdate4"		<name>layoutupdate4</name>
	title="layoutupdate4">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct layoutupdate4 {		struct layoutupdate4 {
	layouttype4 lou_type;		layouttype4 lou_type;
	opaque lou_body&lt;>;		opaque lou_body<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The layoutupdate4 data type is used by the client to return		The layoutupdate4 data type is used by the client to return
	updated layout information to the metadata server via the		updated layout information to the metadata server via the
	LAYOUTCOMMIT (<xref target="OP_LAYOUTCOMMIT" />) operation.		LAYOUTCOMMIT (<xref target="OP_LAYOUTCOMMIT" format="default"/>) operatio n.
	This data type provides a channel to pass		This data type provides a channel to pass
	layout type specific information (in field lou_body)		layout type specific information (in field lou_body)
	back to the metadata server.		back to the metadata server.
	For example, for the block/volume layout type, this could include the		For example, for the block/volume layout type, this could include the
	list of reserved blocks that were written. The contents of		list of reserved blocks that were written. The contents of
	the opaque lou_body argument are determined by the layout type.		the opaque lou_body argument are determined by the layout type.
	The NFSv4.1 file-based layout		The NFSv4.1 file-based layout
	does not use this data type; if lou_type is LAYOUT4_NFSV4_1_FILES,		does not use this data type; if lou_type is LAYOUT4_NFSV4_1_FILES,
	the lou_body field MUST		the lou_body field <bcp14>MUST</bcp14>
	have a zero length.		have a zero length.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="layouthint4" numbered="true">
	<section toc="exclude" anchor="layouthint4" title="layouthint4">		<name>layouthint4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct layouthint4 {		struct layouthint4 {
	layouttype4 loh_type;		layouttype4 loh_type;
	opaque loh_body&lt;>;		opaque loh_body<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The layouthint4 data type is used by the client to pass in a		The layouthint4 data type is used by the client to pass in a
	hint about the type of layout it would like created for a particular		hint about the type of layout it would like created for a particular
	file. It is the data type specified by the layout_hint		file. It is the data type specified by the layout_hint
	attribute described in <xref target="attrdef_layout_hint" />.		attribute described in <xref target="attrdef_layout_hint" format="default "/>.
	The metadata server may ignore the hint		The metadata server may ignore the hint
	or may selectively ignore fields within the hint. This hint should		or may selectively ignore fields within the hint. This hint should
	be provided at create time as part of the initial attributes within		be provided at create time as part of the initial attributes within
	OPEN. The loh_body field is specific to the type of layout (loh_type).		OPEN. The loh_body field is specific to the type of layout (loh_type).
	The NFSv4.1 file-based layout uses the nfsv4_1_file_layouthint4		The NFSv4.1 file-based layout uses the nfsv4_1_file_layouthint4
	data type as defined in <xref target="file_data_types" />.		data type as defined in <xref target="file_data_types" format="default"/>
	</t>		.
	</section>		</t>
			</section>
	<section toc="exclude" anchor="layoutiomode4"		<section toc="exclude" anchor="layoutiomode4" numbered="true">
	title="layoutiomode4">		<name>layoutiomode4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	enum layoutiomode4 {		enum layoutiomode4 {
	LAYOUTIOMODE4_READ = 1,		LAYOUTIOMODE4_READ = 1,
	LAYOUTIOMODE4_RW = 2,		LAYOUTIOMODE4_RW = 2,
	LAYOUTIOMODE4_ANY = 3		LAYOUTIOMODE4_ANY = 3
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The iomode specifies whether the client intends to just read or both		The iomode specifies whether the client intends to just read or both
	read and write the data represented by the		read and write the data represented by the
	layout. While the LAYOUTIOMODE4_ANY iomode MUST NOT be used in		layout. While the LAYOUTIOMODE4_ANY iomode <bcp14>MUST NOT</bcp14> be us
	the arguments to the LAYOUTGET operation, it MAY		ed in
			the arguments to the LAYOUTGET operation, it <bcp14>MAY</bcp14>
	be used in the arguments to the LAYOUTRETURN and CB_LAYOUTRECALL		be used in the arguments to the LAYOUTRETURN and CB_LAYOUTRECALL
	operations. The LAYOUTIOMODE4_ANY iomode		operations. The LAYOUTIOMODE4_ANY iomode
	specifies that layouts pertaining to both LAYOUTIOMODE4_READ		specifies that layouts pertaining to both LAYOUTIOMODE4_READ
	and LAYOUTIOMODE4_RW iomodes are being returned or recalled,		and LAYOUTIOMODE4_RW iomodes are being returned or recalled,
	respectively. The metadata server's use of the iomode may		respectively. The metadata server's use of the iomode may
	depend on the layout type being used. The storage devices MAY		depend on the layout type being used. The storage devices <bcp14>MAY</b cp14>
	validate I/O accesses against the iomode and reject invalid accesses.		validate I/O accesses against the iomode and reject invalid accesses.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="nfs_impl_id4" numbered="true">
	<section toc="exclude" anchor="nfs_impl_id4" title="nfs_impl_id4">		<name>nfs_impl_id4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct nfs_impl_id4 {		struct nfs_impl_id4 {
	utf8str_cis nii_domain;		utf8str_cis nii_domain;
	utf8str_cs nii_name;		utf8str_cs nii_name;
	nfstime4 nii_date;		nfstime4 nii_date;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	This data type is used to identify client and server		This data type is used to identify client and server
	implementation details. The nii_domain field is the DNS domain		implementation details. The nii_domain field is the DNS domain
	name with which the implementor is associated. The nii_name		name with which the implementor is associated. The nii_name
	field is the product name of the implementation and is		field is the product name of the implementation and is
	completely free form. It is RECOMMENDED that the nii_name be		completely free form. It is <bcp14>RECOMMENDED</bcp14> that the nii_name be
	used to distinguish machine architecture, machine platforms,		used to distinguish machine architecture, machine platforms,
	revisions, versions, and patch levels. The nii_date field is		revisions, versions, and patch levels. The nii_date field is
	the timestamp of when the software instance was published or		the timestamp of when the software instance was published or
	built.		built.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="threshold_item4" numbered="true">
	<section toc="exclude" anchor="threshold_item4" title="threshold_item4">		<name>threshold_item4</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct threshold_item4 {		struct threshold_item4 {
	layouttype4 thi_layout_type;		layouttype4 thi_layout_type;
	bitmap4 thi_hintset;		bitmap4 thi_hintset;
	opaque thi_hintlist&lt;>;		opaque thi_hintlist<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	This data type contains a list of hints specific to		This data type contains a list of hints specific to
	a layout type for helping the client determine when		a layout type for helping the client determine when
	it should send I/O directly through the metadata		it should send I/O directly through the metadata
	server versus the storage devices. The data type		server versus the storage devices. The data type
	consists of the layout type (thi_layout_type),		consists of the layout type (thi_layout_type),
	a bitmap (thi_hintset) describing the set of		a bitmap (thi_hintset) describing the set of
	hints supported by the server (they may differ		hints supported by the server (they may differ
	based on the layout type), and a list of hints		based on the layout type), and a list of hints
	(thi_hintlist) whose content is determined by		(thi_hintlist) whose content is determined by
	the hintset bitmap. See the mdsthreshold attribute		the hintset bitmap. See the mdsthreshold attribute
	for more details.		for more details.
	</t>		</t>
	<t>		<t>
	The thi_hintset field is a bitmap of the following values:		The thi_hintset field is a bitmap of the following values:
	</t>		</t>
	<texttable>		<table align="center" anchor="table2">
	<ttcol align='left'>name</ttcol>		<thead>
	<ttcol align='left'>#</ttcol>		<tr>
	<ttcol align='left'>Data Type</ttcol>		<th align="left">name</th>
	<ttcol align='left'>Description</ttcol>		<th align="left">#</th>
			<th align="left">Data Type</th>
	<c>threshold4_read_size</c><c>0</c><c>length4</c>		<th align="left">Description</th>
	<c>		</tr>
			</thead>
			<tbody>
			<tr>
			<td align="left">threshold4_read_size</td>
			<td align="left">0</td>
			<td align="left">length4</td>
			<td align="left">
	If a file's length is less than the value of threshold4_read_size,		If a file's length is less than the value of threshold4_read_size,
	then it is RECOMMENDED that the client read from the file via the MDS and not		then it is <bcp14>RECOMMENDED</bcp14> that the client read from the f ile via the MDS and not
	a storage device.		a storage device.
	</c>		</td>
	<c>threshold4_write_size</c><c>1</c><c>length4</c>		</tr>
	<c>		<tr>
			<td align="left">threshold4_write_size</td>
			<td align="left">1</td>
			<td align="left">length4</td>
			<td align="left">
	If a file's length is less than the value of threshold4_write_size,		If a file's length is less than the value of threshold4_write_size,
	then it is RECOMMENDED that the client write to the file via the MDS and not		then it is <bcp14>RECOMMENDED</bcp14> that the client write to the fi le via the MDS and not
	a storage device.		a storage device.
	</c>		</td>
	<c>threshold4_read_iosize</c><c>2</c><c>length4</c>		</tr>
	<c>		<tr>
	For read I/O sizes below this threshold, it is RECOMMENDED to		<td align="left">threshold4_read_iosize</td>
			<td align="left">2</td>
			<td align="left">length4</td>
			<td align="left">
			For read I/O sizes below this threshold, it is <bcp14>RECOMMENDED</bcp
			14> to
	read data through the MDS.		read data through the MDS.
	</c>		</td>
	<c>threshold4_write_iosize</c><c>3</c><c>length4</c>		</tr>
	<c>		<tr>
	For write I/O sizes below this threshold, it is RECOMMENDED to		<td align="left">threshold4_write_iosize</td>
			<td align="left">3</td>
			<td align="left">length4</td>
			<td align="left">
			For write I/O sizes below this threshold, it is <bcp14>RECOMMENDED</bc
			p14> to
	write data through the MDS.		write data through the MDS.
	</c>		</td>
	</texttable>		</tr>
	</section>		</tbody>
			</table>
	<section toc="exclude" anchor="mdsthreshold4" title="mdsthreshold4">		</section>
	<figure>		<section toc="exclude" anchor="mdsthreshold4" numbered="true">
	<artwork>		<name>mdsthreshold4</name>
			<sourcecode type="xdr"><![CDATA[
	struct mdsthreshold4 {		struct mdsthreshold4 {
	threshold_item4 mth_hints&lt;>;		threshold_item4 mth_hints<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	This data type holds an array of elements of data type		This data type holds an array of elements of data type
	threshold_item4,		threshold_item4,
	each of which is valid for a particular layout type. An array		each of which is valid for a particular layout type. An array
	is necessary because a server can support multiple layout types		is necessary because a server can support multiple layout types
	for a single file.		for a single file.
	</t>		</t>
			</section>
			</section>
	</section>		</section>
			<section anchor="Filehandles" numbered="true" toc="default">
	</section>		<name>Filehandles</name>
	</section>		<t>
	<!-- End of Data Types -->
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->
	<!-- Copyright (C) The IETF Trust (2007-2008) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="Filehandles" title="Filehandles">
	<t>
	The filehandle in the NFS protocol is a per-server unique identifier		The filehandle in the NFS protocol is a per-server unique identifier
	for a file system object. The contents of the filehandle are opaque		for a file system object. The contents of the filehandle are opaque
	to the client. Therefore, the server is responsible for translating		to the client. Therefore, the server is responsible for translating
	the filehandle to an internal representation of the file system		the filehandle to an internal representation of the file system
	object.		object.
	</t>		</t>
	<section title="Obtaining the First Filehandle">		<section numbered="true" toc="default">
	<t>		<name>Obtaining the First Filehandle</name>
			<t>
	The operations of the NFS protocol are defined in terms of one		The operations of the NFS protocol are defined in terms of one
	or more filehandles. Therefore, the client needs a filehandle		or more filehandles. Therefore, the client needs a filehandle
	to initiate communication with the server. With the NFSv3		to initiate communication with the server. With the NFSv3
	protocol (<xref target="RFC1813">RFC 1813</xref>), there		protocol (<xref target="RFC1813" format="default">RFC 1813</xref>), there
	exists an ancillary protocol to obtain this first filehandle.		exists an ancillary protocol to obtain this first filehandle.
	The MOUNT protocol, RPC program number 100005, provides the		The MOUNT protocol, RPC program number 100005, provides the
	mechanism of translating a string-based file system pathname to		mechanism of translating a string-based file system pathname to
	a filehandle, which can then be used by the NFS protocols.		a filehandle, which can then be used by the NFS protocols.
	</t>		</t>
	<t>		<t>
	The MOUNT protocol has deficiencies in the area of security and		The MOUNT protocol has deficiencies in the area of security and
	use via firewalls. This is one reason that the use of the		use via firewalls. This is one reason that the use of the
	public filehandle was introduced in <xref		public filehandle was introduced in <xref target="RFC2054" format="default
	target="RFC2054">RFC 2054</xref> and <xref		">RFC 2054</xref> and <xref target="RFC2055" format="default">RFC 2055</xref>.
	target="RFC2055">RFC 2055</xref>. With the use of the public		With the use of the public
	filehandle in combination with the LOOKUP operation in the NFSv3		filehandle in combination with the LOOKUP operation in the NFSv3
	protocol, it has been demonstrated that the		protocol, it has been demonstrated that the
	MOUNT protocol is unnecessary for viable interaction between NFS		MOUNT protocol is unnecessary for viable interaction between NFS
	client and server.		client and server.
	</t>		</t>
	<t>		<t>
	Therefore, the NFSv4.1 protocol will not use an ancillary		Therefore, the NFSv4.1 protocol will not use an ancillary
	protocol for translation from string-based pathnames to a filehandle.		protocol for translation from string-based pathnames to a filehandle.
	Two special filehandles will be used as starting points for the NFS		Two special filehandles will be used as starting points for the NFS
	client.		client.
	</t>		</t>
	<section title="Root Filehandle">		<section numbered="true" toc="default">
	<t>		<name>Root Filehandle</name>
			<t>
	The first of the special filehandles is the ROOT filehandle. The ROOT		The first of the special filehandles is the ROOT filehandle. The ROOT
	filehandle is the "conceptual" root of the file system namespace at		filehandle is the "conceptual" root of the file system namespace at
	the NFS server. The client uses or starts with the ROOT filehandle		the NFS server. The client uses or starts with the ROOT filehandle
	by employing the PUTROOTFH operation. The PUTROOTFH operation		by employing the PUTROOTFH operation. The PUTROOTFH operation
	instructs the server to set the "current" filehandle to the ROOT of		instructs the server to set the "current" filehandle to the ROOT of
	the server's file tree. Once this PUTROOTFH operation is used, the		the server's file tree. Once this PUTROOTFH operation is used, the
	client can then traverse the entirety of the server's file tree with		client can then traverse the entirety of the server's file tree with
	the LOOKUP operation. A complete discussion of the server namespace		the LOOKUP operation. A complete discussion of the server namespace
	is in <xref target="single_server_namespace"/>.		is in <xref target="single_server_namespace" format="default"/>.
	</t>		</t>
	</section>		</section>
	<section title="Public Filehandle">		<section numbered="true" toc="default">
	<t>		<name>Public Filehandle</name>
			<t>
	The second special filehandle is the PUBLIC filehandle. Unlike the		The second special filehandle is the PUBLIC filehandle. Unlike the
	ROOT filehandle, the PUBLIC filehandle may be bound or represent an		ROOT filehandle, the PUBLIC filehandle may be bound or represent an
	arbitrary file system object at the server. The server is responsible		arbitrary file system object at the server. The server is responsible
	for this binding. It may be that the PUBLIC filehandle and the ROOT		for this binding. It may be that the PUBLIC filehandle and the ROOT
	filehandle refer to the same file system object. However, it is up to		filehandle refer to the same file system object. However, it is up to
	the administrative software at the server and the policies of the		the administrative software at the server and the policies of the
	server administrator to define the binding of the PUBLIC filehandle		server administrator to define the binding of the PUBLIC filehandle
	and server file system object. The client may not make any		and server file system object. The client may not make any
	assumptions about this binding. The client uses the PUBLIC filehandle		assumptions about this binding. The client uses the PUBLIC filehandle
	via the PUTPUBFH operation.		via the PUTPUBFH operation.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section title="Filehandle Types">		<section numbered="true" toc="default">
	<t>		<name>Filehandle Types</name>
			<t>
	In the NFSv3 protocol, there was one type of filehandle		In the NFSv3 protocol, there was one type of filehandle
	with a single set of semantics. This type of filehandle is termed		with a single set of semantics. This type of filehandle is termed
	"persistent" in NFSv4.1. The semantics of a persistent		"persistent" in NFSv4.1. The semantics of a persistent
	filehandle remain the same as before. A new type of filehandle		filehandle remain the same as before. A new type of filehandle
	introduced in NFSv4.1 is the "volatile" filehandle, which		introduced in NFSv4.1 is the "volatile" filehandle, which
	attempts to accommodate certain server environments.		attempts to accommodate certain server environments.
	</t>		</t>
	<t>		<t>
	The volatile filehandle type was introduced to address server		The volatile filehandle type was introduced to address server
	functionality or implementation issues that make correct		functionality or implementation issues that make correct
	implementation of a persistent filehandle infeasible. Some server		implementation of a persistent filehandle infeasible. Some server
	environments do not provide a file-system-level invariant that can be		environments do not provide a file-system-level invariant that can be
	used to construct a persistent filehandle. The underlying server		used to construct a persistent filehandle. The underlying server
	file system may not provide the invariant or the server's file system		file system may not provide the invariant or the server's file system
	programming interfaces may not provide access to the needed invariant.		programming interfaces may not provide access to the needed invariant.
	Volatile filehandles may ease the implementation of server		Volatile filehandles may ease the implementation of server
	functionality such as hierarchical storage management or file system		functionality such as hierarchical storage management or file system
	reorganization or migration. However, the volatile filehandle		reorganization or migration. However, the volatile filehandle
	increases the implementation burden for the client.		increases the implementation burden for the client.
	</t>		</t>
	<t>		<t>
	Since the client will need to handle persistent and volatile		Since the client will need to handle persistent and volatile
	filehandles differently, a file attribute is defined that may be used		filehandles differently, a file attribute is defined that may be used
	by the client to determine the filehandle types being returned by the		by the client to determine the filehandle types being returned by the
	server.		server.
	</t>		</t>
	<section title="General Properties of a Filehandle">		<section numbered="true" toc="default">
	<t>		<name>General Properties of a Filehandle</name>
			<t>
	The filehandle contains all the information the		The filehandle contains all the information the
	server needs to distinguish an individual file.		server needs to distinguish an individual file.
	To the client, the filehandle is opaque. The		To the client, the filehandle is opaque. The
	client stores filehandles for use in a later		client stores filehandles for use in a later
	request and can compare two filehandles from the		request and can compare two filehandles from the
	same server for equality by doing a byte-by-byte		same server for equality by doing a byte-by-byte
	comparison. However, the client MUST NOT otherwise		comparison. However, the client <bcp14>MUST NOT</bcp14> otherwise
	interpret the contents of filehandles. If two		interpret the contents of filehandles. If two
	filehandles from the same server are equal, they		filehandles from the same server are equal, they
	MUST refer to the same file. Servers SHOULD try		<bcp14>MUST</bcp14> refer to the same file. Servers <bcp14>SHOULD</bcp1 4> try
	to maintain a one-to-one correspondence between		to maintain a one-to-one correspondence between
	filehandles and files, but this is not required.		filehandles and files, but this is not required.
	Clients MUST use filehandle comparisons only to		Clients <bcp14>MUST</bcp14> use filehandle comparisons only to
	improve performance, not for correct behavior.		improve performance, not for correct behavior.
	All clients need to be prepared for situations		All clients need to be prepared for situations
	in which it cannot be determined whether two		in which it cannot be determined whether two
	filehandles denote the same object and in such		filehandles denote the same object and in such
	cases, avoid making invalid assumptions that might		cases, avoid making invalid assumptions that might
	cause incorrect behavior. Further discussion		cause incorrect behavior. Further discussion
	of filehandle and attribute comparison in the		of filehandle and attribute comparison in the
	context of data caching is presented in <xref		context of data caching is presented in <xref target="data_caching_and_f
	target="data_caching_and_file_identity"/>.		ile_identity" format="default"/>.
	</t>		</t>
	<t>		<t>
	As an example, in the case that two different pathnames when		As an example, in the case that two different pathnames when
	traversed at the server terminate at the same file system object, the		traversed at the server terminate at the same file system object, the
	server SHOULD return the same filehandle for each path. This can		server <bcp14>SHOULD</bcp14> return the same filehandle for each path.
	occur if a hard link (see <xref target="hardlink"/>) is used		This can
			occur if a hard link (see <xref target="hardlink" format="default"/>) is
			used
	to create two file names that refer to the same underlying		to create two file names that refer to the same underlying
	file object and associated data. For example, if paths /a/b/c		file object and associated data. For example, if paths /a/b/c
	and /a/d/c refer to the same file, the server SHOULD return		and /a/d/c refer to the same file, the server <bcp14>SHOULD</bcp14> retu rn
	the same filehandle for both pathnames' traversals.		the same filehandle for both pathnames' traversals.
	</t>		</t>
	</section>		</section>
	<section title="Persistent Filehandle">		<section numbered="true" toc="default">
	<t>		<name>Persistent Filehandle</name>
			<t>
	A persistent filehandle is defined as having a fixed value for the		A persistent filehandle is defined as having a fixed value for the
	lifetime of the file system object to which it refers. Once the		lifetime of the file system object to which it refers. Once the
	server creates the filehandle for a file system object, the server		server creates the filehandle for a file system object, the server
	MUST accept the same filehandle for the object for the lifetime of the		<bcp14>MUST</bcp14> accept the same filehandle for the object for the li
	object. If the server restarts, the NFS server MUST honor		fetime of the
			object. If the server restarts, the NFS server <bcp14>MUST</bcp14> hono
			r
	the same filehandle value as it did in the server's previous		the same filehandle value as it did in the server's previous
	instantiation. Similarly, if the file system is migrated, the new NFS		instantiation. Similarly, if the file system is migrated, the new NFS
	server MUST honor the same filehandle as the old NFS server.		server <bcp14>MUST</bcp14> honor the same filehandle as the old NFS serv
	</t>		er.
	<t>		</t>
			<t>
	The persistent filehandle will be become stale or invalid when the		The persistent filehandle will be become stale or invalid when the
	file system object is removed. When the server is presented with a		file system object is removed. When the server is presented with a
	persistent filehandle that refers to a deleted object, it MUST return		persistent filehandle that refers to a deleted object, it <bcp14>MUST</b cp14> return
	an error of NFS4ERR_STALE. A filehandle may become stale when the		an error of NFS4ERR_STALE. A filehandle may become stale when the
	file system containing the object is no longer available. The file		file system containing the object is no longer available. The file
	system may become unavailable if it exists on removable media and the		system may become unavailable if it exists on removable media and the
	media is no longer available at the server or the file system in whole		media is no longer available at the server or the file system in whole
	has been destroyed or the file system has simply been removed from the		has been destroyed or the file system has simply been removed from the
	server's namespace (i.e., unmounted in a UNIX environment).		server's namespace (i.e., unmounted in a UNIX environment).
	</t>		</t>
	</section>		</section>
	<section title="Volatile Filehandle">		<section numbered="true" toc="default">
	<t>		<name>Volatile Filehandle</name>
			<t>
	A volatile filehandle does not share the same longevity		A volatile filehandle does not share the same longevity
	characteristics of a persistent filehandle. The server may		characteristics of a persistent filehandle. The server may
	determine that a volatile filehandle is no longer valid at many		determine that a volatile filehandle is no longer valid at many
	different points in time. If the server can definitively determine		different points in time. If the server can definitively determine
	that a volatile filehandle refers to an object that has been removed,		that a volatile filehandle refers to an object that has been removed,
	the server should return NFS4ERR_STALE to the client (as is the case		the server should return NFS4ERR_STALE to the client (as is the case
	for persistent filehandles). In all other cases where the server		for persistent filehandles). In all other cases where the server
	determines that a volatile filehandle can no longer be used, it should		determines that a volatile filehandle can no longer be used, it should
	return an error of NFS4ERR_FHEXPIRED.		return an error of NFS4ERR_FHEXPIRED.
	</t>		</t>
	<t>		<t>
	The REQUIRED attribute "fh_expire_type" is used by the client to		The <bcp14>REQUIRED</bcp14> attribute "fh_expire_type" is used by the cl
			ient to
	determine what type of filehandle the server is providing for a		determine what type of filehandle the server is providing for a
	particular file system. This attribute is a bitmask with the		particular file system. This attribute is a bitmask with the
	following values:		following values:
	</t>		</t>
	<t>		<dl newline="false" spacing="normal">
	<list style="hanging">		<dt>FH4_PERSISTENT</dt>
	<t hangText="FH4_PERSISTENT">		<dd>
	The value of FH4_PERSISTENT is used to indicate a persistent		The value of FH4_PERSISTENT is used to indicate a persistent
	filehandle, which is valid until the object is removed from the		filehandle, which is valid until the object is removed from the
	file system. The server will not return NFS4ERR_FHEXPIRED for this		file system. The server will not return NFS4ERR_FHEXPIRED for this
	filehandle. FH4_PERSISTENT is defined as a value in which none of t he		filehandle. FH4_PERSISTENT is defined as a value in which none of t he
	bits specified below are set.		bits specified below are set.
	</t>		</dd>
	<t hangText="FH4_VOLATILE_ANY">		<dt>FH4_VOLATILE_ANY</dt>
			<dd>
	The filehandle may expire at any time, except as specifically		The filehandle may expire at any time, except as specifically
	excluded (i.e., FH4_NO_EXPIRE_WITH_OPEN).		excluded (i.e., FH4_NO_EXPIRE_WITH_OPEN).
	</t>		</dd>
	<t hangText="FH4_NOEXPIRE_WITH_OPEN">		<dt>FH4_NOEXPIRE_WITH_OPEN</dt>
			<dd>
	May only be set when FH4_VOLATILE_ANY is set. If this bit is set,		May only be set when FH4_VOLATILE_ANY is set. If this bit is set,
	then the meaning of FH4_VOLATILE_ANY is qualified to exclude any		then the meaning of FH4_VOLATILE_ANY is qualified to exclude any
	expiration of the filehandle when it is open.		expiration of the filehandle when it is open.
	</t>		</dd>
	<t hangText="FH4_VOL_MIGRATION">		<dt>FH4_VOL_MIGRATION</dt>
			<dd>
	The filehandle will expire as a result of a file system		The filehandle will expire as a result of a file system
	transition (migration or replication), in those cases in		transition (migration or replication), in those cases in
	which the continuity of filehandle use is not specified by		which the continuity of filehandle use is not specified by
	handle class information		handle class information
	within the fs_locations_info attribute. When this bit is		within the fs_locations_info attribute. When this bit is
	set, clients without access to fs_locations_info		set, clients without access to fs_locations_info
	information should assume that filehandles will expire on file		information should assume that filehandles will expire on file
	system transitions.		system transitions.
	</t>		</dd>
	<t hangText="FH4_VOL_RENAME">		<dt>FH4_VOL_RENAME</dt>
			<dd>
	The filehandle will expire during rename. This includes a rename by		The filehandle will expire during rename. This includes a rename by
	the requesting client or a rename by any other client. If FH4_VOL_A NY		the requesting client or a rename by any other client. If FH4_VOL_A NY
	is set, FH4_VOL_RENAME is redundant.		is set, FH4_VOL_RENAME is redundant.
	</t>		</dd>
	</list>		</dl>
	</t>		<t>
	<t>
	Servers that provide volatile filehandles that can expire		Servers that provide volatile filehandles that can expire
	while open require special care as regards handling of RENAMEs		while open require special care as regards handling of RENAMEs
	and REMOVEs. This situation can arise if FH4_VOL_MIGRATION or		and REMOVEs. This situation can arise if FH4_VOL_MIGRATION or
	FH4_VOL_RENAME is set, if FH4_VOLATILE_ANY is set and		FH4_VOL_RENAME is set, if FH4_VOLATILE_ANY is set and
	FH4_NOEXPIRE_WITH_OPEN is not set, or if a non-read-only file system		FH4_NOEXPIRE_WITH_OPEN is not set, or if a non-read-only file system
	has a transition target in a different handle		has a transition target in a different handle
	class. In these cases, the server should deny a RENAME		class. In these cases, the server should deny a RENAME
	or REMOVE that would affect an OPEN file of any of the		or REMOVE that would affect an OPEN file of any of the
	components leading to the OPEN file. In addition, the server		components leading to the OPEN file. In addition, the server
	should deny all RENAME or REMOVE requests during the grace period,		should deny all RENAME or REMOVE requests during the grace period,
	in order to make sure that reclaims of files where filehandles		in order to make sure that reclaims of files where filehandles
	may have expired do not do a reclaim for the wrong file.		may have expired do not do a reclaim for the wrong file.
	</t>		</t>
	<t>		<t>
	Volatile filehandles are especially suitable for implementation		Volatile filehandles are especially suitable for implementation
	of the pseudo file systems used to bridge exports. See		of the pseudo file systems used to bridge exports. See
	<xref target="pseudo_fs_volatility" /> for a discussion of this.		<xref target="pseudo_fs_volatility" format="default"/> for a discussion
	</t>		of this.
	</section>		</t>
	</section>		</section>
	<section title="One Method of Constructing a Volatile Filehandle">		</section>
	<t>		<section numbered="true" toc="default">
			<name>One Method of Constructing a Volatile Filehandle</name>
			<t>
	A volatile filehandle, while opaque to the client, could contain:		A volatile filehandle, while opaque to the client, could contain:
	</t>		</t>
	<figure>		<sourcecode type="pseudocode"><![CDATA[
	<artwork>
	[volatile bit = 1 | server boot time | slot | generation number]		[volatile bit = 1 | server boot time | slot | generation number]
	o slot is an index in the server volatile filehandle table		]]></sourcecode>
			<ul>
	o generation number is the generation number for the table entry/		<li>slot is an index in the server volatile filehandle table</li>
	slot		<li>generation number is the generation number for the table entry/slot</li>
	</artwork>		</ul>
	</figure>		<t>
	<t>
	When the client presents a volatile filehandle, the server makes the		When the client presents a volatile filehandle, the server makes the
	following checks, which assume that the check for the volatile bit has		following checks, which assume that the check for the volatile bit has
	passed. If the server boot time is less than the current server boot		passed. If the server boot time is less than the current server boot
	time, return NFS4ERR_FHEXPIRED. If slot is out of range, return		time, return NFS4ERR_FHEXPIRED. If slot is out of range, return
	NFS4ERR_BADHANDLE. If the generation number does not match, return		NFS4ERR_BADHANDLE. If the generation number does not match, return
	NFS4ERR_FHEXPIRED.		NFS4ERR_FHEXPIRED.
	</t>		</t>
	<t>		<t>
	When the server restarts, the table is gone (it is volatile).		When the server restarts, the table is gone (it is volatile).
	</t>		</t>
	<t>		<t>
	If the volatile bit is 0, then it is a persistent filehandle with a		If the volatile bit is 0, then it is a persistent filehandle with a
	different structure following it.		different structure following it.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="Client Recovery from Filehandle Expiration">		<name>Client Recovery from Filehandle Expiration</name>
	<t>		<t>
	If possible, the client SHOULD recover from the receipt of an		If possible, the client <bcp14>SHOULD</bcp14> recover from the receipt of
			an
	NFS4ERR_FHEXPIRED error. The client must take on additional		NFS4ERR_FHEXPIRED error. The client must take on additional
	responsibility so that it may prepare itself to recover from the		responsibility so that it may prepare itself to recover from the
	expiration of a volatile filehandle. If the server returns persistent		expiration of a volatile filehandle. If the server returns persistent
	filehandles, the client does not need these additional steps.		filehandles, the client does not need these additional steps.
	</t>		</t>
	<t>		<t>
	For volatile filehandles, most commonly the client will need to store		For volatile filehandles, most commonly the client will need to store
	the component names leading up to and including the file system object		the component names leading up to and including the file system object
	in question. With these names, the client should be able to recover		in question. With these names, the client should be able to recover
	by finding a filehandle in the namespace that is still available or		by finding a filehandle in the namespace that is still available or
	by starting at the root of the server's file system namespace.		by starting at the root of the server's file system namespace.
	</t>		</t>
	<t>		<t>
	If the expired filehandle refers to an object that has been removed		If the expired filehandle refers to an object that has been removed
	from the file system, obviously the client will not be able to recover		from the file system, obviously the client will not be able to recover
	from the expired filehandle.		from the expired filehandle.
	</t>		</t>
	<t>		<t>
	It is also possible that the expired filehandle refers to a file that		It is also possible that the expired filehandle refers to a file that
	has been renamed. If the file was renamed by another client, again it		has been renamed. If the file was renamed by another client, again it
	is possible that the original client will not be able to recover.		is possible that the original client will not be able to recover.
	However, in the case that the client itself is renaming the file and		However, in the case that the client itself is renaming the file and
	the file is open, it is possible that the client may be able to		the file is open, it is possible that the client may be able to
	recover. The client can determine the new pathname based on the		recover. The client can determine the new pathname based on the
	processing of the rename request. The client can then regenerate the		processing of the rename request. The client can then regenerate the
	new filehandle based on the new pathname. The client could also use		new filehandle based on the new pathname. The client could also use
	the COMPOUND procedure to construct a series of operations		the COMPOUND procedure to construct a series of operations
	like:		like:
	<figure>		</t>
	<artwork>		<sourcecode type="nfsv4compound"><![CDATA[
	RENAME A B		RENAME A B
	LOOKUP B		LOOKUP B
	GETFH		GETFH
	</artwork>		]]></sourcecode>
	</figure>		<t>
	Note that the COMPOUND procedure does not provide atomicity. This		Note that the COMPOUND procedure does not provide atomicity. This
	example only reduces the overhead of recovering from an expired		example only reduces the overhead of recovering from an expired
	filehandle.		filehandle.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="file_attributes" numbered="true" toc="default">
	$ -->		<name>File Attributes</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<t>
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="file_attributes" title="File Attributes">
	<t>
	To meet the requirements of extensibility and increased		To meet the requirements of extensibility and increased
	interoperability with non-UNIX platforms, attributes need to be handled		interoperability with non-UNIX platforms, attributes need to be handled
	in a flexible manner. The NFSv3 fattr3 structure contains a		in a flexible manner. The NFSv3 fattr3 structure contains a
	fixed list of attributes that not all clients and servers are able to		fixed list of attributes that not all clients and servers are able to
	support or care about. The fattr3 structure cannot be extended as		support or care about. The fattr3 structure cannot be extended as
	new needs arise and it provides no way to indicate non-support. With		new needs arise and it provides no way to indicate non-support. With
	the NFSv4.1 protocol, the client is able to query what attributes		the NFSv4.1 protocol, the client is able to query what attributes
	the server supports and construct requests with only those supported		the server supports and construct requests with only those supported
	attributes (or a subset thereof).		attributes (or a subset thereof).
	</t>		</t>
	<t>		<t>
	To this end, attributes are divided into three groups: REQUIRED,		To this end, attributes are divided into three groups: <bcp14>REQUIRED</bcp1
	RECOMMENDED, and named. Both REQUIRED and RECOMMENDED attributes are		4>,
			<bcp14>RECOMMENDED</bcp14>, and named. Both <bcp14>REQUIRED</bcp14> and <bc
			p14>RECOMMENDED</bcp14> attributes are
	supported in the NFSv4.1 protocol by a specific and well-defined		supported in the NFSv4.1 protocol by a specific and well-defined
	encoding and are identified by number. They are requested by setting		encoding and are identified by number. They are requested by setting
	a bit in the bit vector sent in the GETATTR request; the server		a bit in the bit vector sent in the GETATTR request; the server
	response includes a bit vector to list what attributes were returned		response includes a bit vector to list what attributes were returned
	in the response. New REQUIRED or RECOMMENDED attributes may be added		in the response. New <bcp14>REQUIRED</bcp14> or <bcp14>RECOMMENDED</bcp14> attributes may be added
	to the NFSv4 protocol as part of a new minor version		to the NFSv4 protocol as part of a new minor version
	by publishing a		by publishing a
	Standards Track RFC that allocates a new attribute number value and		Standards Track RFC that allocates a new attribute number value and
	defines the encoding for the attribute. See		defines the encoding for the attribute. See
	<xref target="minor_versioning"/> for further		<xref target="minor_versioning" format="default"/> for further
	discussion.		discussion.
	</t>		</t>
	<t>		<t>
	Named attributes are accessed by the new OPENATTR operation, which		Named attributes are accessed by the new OPENATTR operation, which
	accesses a hidden directory of attributes associated with a file		accesses a hidden directory of attributes associated with a file
	system object. OPENATTR takes a filehandle for the object and returns		system object. OPENATTR takes a filehandle for the object and returns
	the filehandle for the attribute hierarchy. The filehandle for the		the filehandle for the attribute hierarchy. The filehandle for the
	named attributes is a directory object accessible by LOOKUP or READDIR		named attributes is a directory object accessible by LOOKUP or READDIR
	and contains files whose names represent the named attributes and		and contains files whose names represent the named attributes and
	whose data bytes are the value of the attribute. For example:		whose data bytes are the value of the attribute. For example:
	</t>		</t>
	<texttable>		<table align="center" anchor="table3">
	<ttcol align='left' />		<tbody>
	<ttcol align='left' />		<tr>
	<ttcol align='left' />		<td align="left">LOOKUP</td>
	<c>LOOKUP</c><c>"foo"</c><c>; look up file</c>		<td align="left">"foo"</td>
	<c>GETATTR</c><c>attrbits</c><c />		<td align="left">; look up file</td>
	<c>OPENATTR</c><c /><c>; access foo's named attributes</c>		</tr>
	<c>LOOKUP</c><c>"x11icon"</c><c>; look up specific attribute</c>		<tr>
	<c>READ</c><c>0,4096</c><c>; read stream of bytes</c>		<td align="left">GETATTR</td>
	</texttable>		<td align="left">attrbits</td>
	<t>		<td align="left"/>
			</tr>
			<tr>
			<td align="left">OPENATTR</td>
			<td align="left"/>
			<td align="left">; access foo's named attributes</td>
			</tr>
			<tr>
			<td align="left">LOOKUP</td>
			<td align="left">"x11icon"</td>
			<td align="left">; look up specific attribute</td>
			</tr>
			<tr>
			<td align="left">READ</td>
			<td align="left">0,4096</td>
			<td align="left">; read stream of bytes</td>
			</tr>
			</tbody>
			</table>
			<t>
	Named attributes are intended for data needed by applications rather		Named attributes are intended for data needed by applications rather
	than by an NFS client implementation. NFS implementors are strongly		than by an NFS client implementation. NFS implementors are strongly
	encouraged to define their new attributes as RECOMMENDED attributes by		encouraged to define their new attributes as <bcp14>RECOMMENDED</bcp14> attr ibutes by
	bringing them to the IETF Standards Track process.		bringing them to the IETF Standards Track process.
	</t>		</t>
	<t>		<t>
	The set of attributes that are classified as REQUIRED is		The set of attributes that are classified as <bcp14>REQUIRED</bcp14> is
	deliberately small since servers need to do whatever it takes to support		deliberately small since servers need to do whatever it takes to support
	them. A server should support as many of the RECOMMENDED attributes		them. A server should support as many of the <bcp14>RECOMMENDED</bcp14> att ributes
	as possible but, by their definition, the server is not required to		as possible but, by their definition, the server is not required to
	support all of them. Attributes are deemed REQUIRED if the data is		support all of them. Attributes are deemed <bcp14>REQUIRED</bcp14> if the d ata is
	both needed by a large number of clients and is not otherwise		both needed by a large number of clients and is not otherwise
	reasonably computable by the client when support is not provided on		reasonably computable by the client when support is not provided on
	the server.		the server.
	</t>		</t>
	<t>		<t>
	Note that the hidden directory returned by OPENATTR is a convenience		Note that the hidden directory returned by OPENATTR is a convenience
	for protocol processing. The client should not make any assumptions		for protocol processing. The client should not make any assumptions
	about the server's implementation of named attributes and whether		about the server's implementation of named attributes and whether
	or not the underlying file system at the server has a named		or not the underlying file system at the server has a named
	attribute directory. Therefore, operations such as SETATTR and		attribute directory. Therefore, operations such as SETATTR and
	GETATTR on the named attribute directory are undefined.		GETATTR on the named attribute directory are undefined.
	</t>		</t>
	<section anchor="mandatory_attributes_intro" title="REQUIRED Attributes">		<section anchor="mandatory_attributes_intro" numbered="true" toc="default"
	<t>		>
	These MUST be supported by every NFSv4.1 client and server in		<name><bcp14>REQUIRED</bcp14> Attributes</name>
	order to ensure a minimum level of interoperability. The server MUST		<t>
	store and return these attributes, and the client MUST be able to		These <bcp14>MUST</bcp14> be supported by every NFSv4.1 client and server
			in
			order to ensure a minimum level of interoperability. The server <bcp14>MU
			ST</bcp14>
			store and return these attributes, and the client <bcp14>MUST</bcp14> be a
			ble to
	function with an attribute set limited to these attributes. With just		function with an attribute set limited to these attributes. With just
	the REQUIRED attributes some client functionality may be impaired or		the <bcp14>REQUIRED</bcp14> attributes some client functionality may be im paired or
	limited in some ways. A client may ask for any of these attributes to		limited in some ways. A client may ask for any of these attributes to
	be returned by setting a bit in the GETATTR request, and the server		be returned by setting a bit in the GETATTR request, and the server
	MUST return their value.		<bcp14>MUST</bcp14> return their value.
	</t>		</t>
	</section>		</section>
	<section anchor="recommended_attributes_intro" title="RECOMMENDED Attributes">		<section anchor="recommended_attributes_intro" numbered="true" toc="defaul
	<t>		t">
			<name><bcp14>RECOMMENDED</bcp14> Attributes</name>
			<t>
	These attributes are understood well enough to warrant support in the		These attributes are understood well enough to warrant support in the
	NFSv4.1 protocol. However, they may not be supported on all		NFSv4.1 protocol. However, they may not be supported on all
	clients and servers. A client may ask for any of these attributes to		clients and servers. A client may ask for any of these attributes to
	be returned by setting a bit in the GETATTR request but must handle		be returned by setting a bit in the GETATTR request but must handle
	the case where the server does not return them. A client MAY ask for		the case where the server does not return them. A client <bcp14>MAY</bcp1
	the set of attributes the server supports and SHOULD NOT request		4> ask for
			the set of attributes the server supports and <bcp14>SHOULD NOT</bcp14> re
			quest
	attributes the server does not support. A server should be tolerant		attributes the server does not support. A server should be tolerant
	of requests for unsupported attributes and simply not return them		of requests for unsupported attributes and simply not return them
	rather than considering the request an error. It is expected that		rather than considering the request an error. It is expected that
	servers will support all attributes they comfortably can and only fail		servers will support all attributes they comfortably can and only fail
	to support attributes that are difficult to support in their		to support attributes that are difficult to support in their
	operating environments. A server should provide attributes whenever		operating environments. A server should provide attributes whenever
	they don't have to "tell lies" to the client. For example, a file		they don't have to "tell lies" to the client. For example, a file
	modification time should be either an accurate time or should not be		modification time should be either an accurate time or should not be
	supported by the server. At times this will be difficult for		supported by the server. At times this will be difficult for
	clients, but a client is better positioned to decide whether and how to		clients, but a client is better positioned to decide whether and how to
	fabricate or construct an attribute or whether to do without the		fabricate or construct an attribute or whether to do without the
	attribute.		attribute.
	</t>		</t>
	</section>		</section>
	<section anchor="named_attributes_intro" title="Named Attributes">		<section anchor="named_attributes_intro" numbered="true" toc="default">
	<t>		<name>Named Attributes</name>
			<t>
	These attributes are not supported by direct encoding in the NFSv4		These attributes are not supported by direct encoding in the NFSv4
	protocol but are accessed by string names rather than		protocol but are accessed by string names rather than
	numbers and correspond to an uninterpreted stream of bytes that are		numbers and correspond to an uninterpreted stream of bytes that are
	stored with the file system object. The namespace for these		stored with the file system object. The namespace for these
	attributes may be accessed by using the OPENATTR operation. The		attributes may be accessed by using the OPENATTR operation. The
	OPENATTR operation returns a filehandle for a virtual "named attribute		OPENATTR operation returns a filehandle for a virtual "named attribute
	directory", and further perusal and modification of the namespace may		directory", and further perusal and modification of the namespace may
	be done using operations that work on more typical directories. In		be done using operations that work on more typical directories. In
	particular, READDIR may be used to get a list of such named attributes,		particular, READDIR may be used to get a list of such named attributes,
	and LOOKUP and OPEN may select a particular attribute. Creation of		and LOOKUP and OPEN may select a particular attribute. Creation of
	a new named attribute may be the result of an OPEN specifying file		a new named attribute may be the result of an OPEN specifying file
	creation.		creation.
	</t>		</t>
	<t>		<t>
	Once an OPEN is done, named attributes may be examined and changed		Once an OPEN is done, named attributes may be examined and changed
	by normal READ and WRITE operations using the filehandles and stateids		by normal READ and WRITE operations using the filehandles and stateids
	returned by OPEN.		returned by OPEN.
	</t>		</t>
	<t>		<t>
	Named attributes and the named attribute directory may have		Named attributes and the named attribute directory may have
	their own (non-named) attributes. Each of these objects MUST have all		their own (non-named) attributes. Each of these objects <bcp14>MUST</bcp1
	of the REQUIRED attributes and may have additional RECOMMENDED		4> have all
			of the <bcp14>REQUIRED</bcp14> attributes and may have additional <bcp14>R
			ECOMMENDED</bcp14>
	attributes. However, the set of attributes for named attributes		attributes. However, the set of attributes for named attributes
	and the named attribute directory need not be, and		and the named attribute directory need not be, and
	typically will not be, as large as that for other objects in that		typically will not be, as large as that for other objects in that
	file system.		file system.
	</t>		</t>
	<t>		<t>
	Named attributes and the named attribute directory might be the		Named attributes and the named attribute directory might be the
	target of delegations (in the case of the named attribute directory,		target of delegations (in the case of the named attribute directory,
	these will be directory delegations). However, since granting of		these will be directory delegations). However, since granting of
	delegations is at the server's discretion, a server		delegations is at the server's discretion, a server
	need not support delegations on named attributes or the named		need not support delegations on named attributes or the named
	attribute directory.		attribute directory.
	</t>		</t>
	<t>		<t>
	It is RECOMMENDED that servers support arbitrary named attributes. A		It is <bcp14>RECOMMENDED</bcp14> that servers support arbitrary named attr
			ibutes. A
	client should not depend on the ability to store any named attributes		client should not depend on the ability to store any named attributes
	in the server's file system. If a server does support named		in the server's file system. If a server does support named
	attributes, a client that is also able to handle them should be able		attributes, a client that is also able to handle them should be able
	to copy a file's data and metadata with complete transparency from		to copy a file's data and metadata with complete transparency from
	one location to another; this would imply that names allowed for		one location to another; this would imply that names allowed for
	regular directory entries are valid for named attribute names as well.		regular directory entries are valid for named attribute names as well.
	</t>		</t>
	<t>		<t>
	In NFSv4.1, the structure of named attribute directories is		In NFSv4.1, the structure of named attribute directories is
	restricted in a number of ways, in order to prevent the development		restricted in a number of ways, in order to prevent the development
	of non-interoperable implementations in which some servers support		of non-interoperable implementations in which some servers support
	a fully general hierarchical directory structure for named attributes		a fully general hierarchical directory structure for named attributes
	while others support a limited but adequate structure for named attributes .		while others support a limited but adequate structure for named attributes .
	In such an environment, clients or applications might come to		In such an environment, clients or applications might come to
	depend on non-portable extensions. The restrictions are:		depend on non-portable extensions. The restrictions are:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	CREATE is not allowed in a named attribute directory. Thus, such		CREATE is not allowed in a named attribute directory. Thus, such
	objects as symbolic links and special files are not allowed to		objects as symbolic links and special files are not allowed to
	be named attributes. Further, directories may not be created		be named attributes. Further, directories may not be created
	in a named attribute directory, so no hierarchical structure of		in a named attribute directory, so no hierarchical structure of
	named attributes for a single object is allowed.		named attributes for a single object is allowed.
	</t>		</li>
	<t>		<li>
	If OPENATTR is done on a named attribute directory or on		If OPENATTR is done on a named attribute directory or on
	a named attribute, the server MUST return NFS4ERR_WRONG_TYPE.		a named attribute, the server <bcp14>MUST</bcp14> return NFS4ERR_WRONG
	</t>		_TYPE.
	<t>		</li>
			<li>
	Doing a RENAME of a named attribute to a different named		Doing a RENAME of a named attribute to a different named
	attribute directory or to an ordinary (i.e., non-named-attribute)		attribute directory or to an ordinary (i.e., non-named-attribute)
	directory is not allowed.		directory is not allowed.
	</t>		</li>
	<t>		<li>
	Creating hard links between named attribute directories or		Creating hard links between named attribute directories or
	between named attribute directories and ordinary directories		between named attribute directories and ordinary directories
	is not allowed.		is not allowed.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Names of attributes will not be controlled by this document or other		Names of attributes will not be controlled by this document or other
	IETF Standards Track documents. See		IETF Standards Track documents. See
	<xref target="namedattributesiana"/>		<xref target="namedattributesiana" format="default"/>
	for further discussion.		for further discussion.
	</t>		</t>
	</section>		</section>
	<section title="Classification of Attributes">		<section numbered="true" toc="default">
	<t>		<name>Classification of Attributes</name>
	Each of the REQUIRED and RECOMMENDED attributes can be classified in		<t>
			Each of the <bcp14>REQUIRED</bcp14> and <bcp14>RECOMMENDED</bcp14> attribu
			tes can be classified in
	one of three categories: per server (i.e., the value of the attribute will		one of three categories: per server (i.e., the value of the attribute will
	be the same for all file objects that share the same		be the same for all file objects that share the same
	server owner; see <xref target="Server_Owners"/> for a definition of serve r		server owner; see <xref target="Server_Owners" format="default"/> for a de finition of server
	owner), per file system (i.e., the value of the attribute will		owner), per file system (i.e., the value of the attribute will
	be the same for some or all file objects that share the		be the same for some or all file objects that share the
	same <xref target="attrdef_fsid">fsid attribute</xref> and		same <xref target="attrdef_fsid" format="default">fsid attribute</xref> an d
	server owner), or per file system		server owner), or per file system
	object. Note that it is possible that some per file system attributes		object. Note that it is possible that some per file system attributes
	may vary within the file system, depending on the value of		may vary within the file system, depending on the value of
	the <xref target="attrdef_homogeneous">"homogeneous"</xref>		the <xref target="attrdef_homogeneous" format="default">"homogeneous"</xre f>
	attribute. Note that the attributes time_access_set and		attribute. Note that the attributes time_access_set and
	time_modify_set are not listed in this section because they are		time_modify_set are not listed in this section because they are
	write-only attributes corresponding to time_access and time_modify,		write-only attributes corresponding to time_access and time_modify,
	and are used in a special instance of SETATTR.		and are used in a special instance of SETATTR.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	The per-server attribute is:		The per-server attribute is:
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	lease_time		lease_time
	</t>		</li>
	</list>		</ul>
	</t>		</li>
	<t>		<li>
			<t>
	The per-file system attributes are:		The per-file system attributes are:
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	supported_attrs, suppattr_exclcreat, fh_expire_type, link_support,		supported_attrs, suppattr_exclcreat, fh_expire_type, link_support,
	symlink_support, unique_handles, aclsupport,		symlink_support, unique_handles, aclsupport,
	cansettime, case_insensitive, case_preserving,		cansettime, case_insensitive, case_preserving,
	chown_restricted, files_avail, files_free,		chown_restricted, files_avail, files_free,
	files_total, fs_locations, homogeneous, maxfilesize,		files_total, fs_locations, homogeneous, maxfilesize,
	maxname, maxread, maxwrite, no_trunc, space_avail,		maxname, maxread, maxwrite, no_trunc, space_avail,
	space_free, space_total, time_delta,		space_free, space_total, time_delta,
	change_policy, fs_status,		change_policy, fs_status,
	fs_layout_type, fs_locations_info, fs_charset_cap		fs_layout_type, fs_locations_info, fs_charset_cap
	</t>		</li>
	</list>		</ul>
	</t>		</li>
	<t>		<li>
			<t>
	The per-file system object attributes are:		The per-file system object attributes are:
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	type, change, size, named_attr, fsid, rdattr_error,		type, change, size, named_attr, fsid, rdattr_error,
	filehandle, acl, archive, fileid, hidden, maxlink,		filehandle, acl, archive, fileid, hidden, maxlink,
	mimetype, mode, numlinks, owner, owner_group, rawdev,		mimetype, mode, numlinks, owner, owner_group, rawdev,
	space_used, system, time_access, time_backup,		space_used, system, time_access, time_backup,
	time_create, time_metadata, time_modify,		time_create, time_metadata, time_modify,
	mounted_on_fileid, dir_notif_delay, dirent_notif_delay,		mounted_on_fileid, dir_notif_delay, dirent_notif_delay,
	dacl, sacl,		dacl, sacl,
	layout_type, layout_hint, layout_blksize, layout_alignment,		layout_type, layout_hint, layout_blksize, layout_alignment,
	mdsthreshold, retention_get, retention_set, retentevt_get,		mdsthreshold, retention_get, retention_set, retentevt_get,
	retentevt_set, retention_hold, mode_set_masked		retentevt_set, retention_hold, mode_set_masked
	</t>		</li>
	</list>		</ul>
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	For quota_avail_hard, quota_avail_soft, and quota_used, see their		For quota_avail_hard, quota_avail_soft, and quota_used, see their
	definitions below for the appropriate classification.		definitions below for the appropriate classification.
	</t>		</t>
			</section>
	</section>		<section anchor="rw_attr" numbered="true" toc="default">
			<name>Set-Only and Get-Only Attributes</name>
	<section anchor="rw_attr"		<t>
	title="Set-Only and Get-Only Attributes">		Some <bcp14>REQUIRED</bcp14> and <bcp14>RECOMMENDED</bcp14> attributes are
	<t>		set-only; i.e., they
	Some REQUIRED and RECOMMENDED attributes are set-only; i.e., they
	can be set via SETATTR but not retrieved via GETATTR. Similarly, some		can be set via SETATTR but not retrieved via GETATTR. Similarly, some
	REQUIRED and RECOMMENDED attributes are get-only; i.e., they		<bcp14>REQUIRED</bcp14> and <bcp14>RECOMMENDED</bcp14> attributes are get-o nly; i.e., they
	can be retrieved via GETATTR but not set via SETATTR. If a client attempts		can be retrieved via GETATTR but not set via SETATTR. If a client attempts
	to set a get-only attribute or get a set-only attributes, the server		to set a get-only attribute or get a set-only attributes, the server
	MUST return NFS4ERR_INVAL.		<bcp14>MUST</bcp14> return NFS4ERR_INVAL.
	</t>		</t>
			</section>
	</section>		<section anchor="mandatory_attributes" numbered="true" toc="default">
			<name><bcp14>REQUIRED</bcp14> Attributes - List and Definition Reference
	<section anchor="mandatory_attributes"		s</name>
	title="REQUIRED Attributes - List and Definition References">		<t>
	<t>		The list of <bcp14>REQUIRED</bcp14> attributes appears in <xref target="req
	The list of REQUIRED attributes appears in <xref target="req_attr_table"/>.		_attr_table" format="default"/>.
	The meaning of the columns of the table are:		The meaning of the columns of the table are:
	<list style='symbols'>		</t>
	<t>Name: The name of the attribute.</t>		<dl spacing="normal">
	<t>Id: The number assigned to the attribute. In		<dt>Name:</dt><dd>The name of the attribute.</dd>
	the event of conflicts between the assigned number and <xref		<dt>Id:</dt><dd>The number assigned to the attribute. In
	target="RFC5662"/>, the latter is		the event of conflicts between the assigned number and <xref target="RFC
			5662" format="default"/>, the latter is
	likely authoritative, but should be resolved with Errata to		likely authoritative, but should be resolved with Errata to
	this document and/or		this document and/or
	<xref target="RFC5662"/>. See <xref target="errata"/> for the Errata pro		<xref target="RFC5662" format="default"/>. See <xref target="errata" for
	cess.		mat="default"/> for the Errata process.</dd>
			<dt>Data Type:</dt><dd>The XDR data type of the attribute.</dd>
	</t>		<dt>Acc:</dt><dd>Access allowed to the attribute. R means
	<t>Data Type: The XDR data type of the attribute.</t>
	<t>
	Acc: Access allowed to the attribute. R means
	read-only (GETATTR may retrieve, SETATTR may not		read-only (GETATTR may retrieve, SETATTR may not
	set). W means write-only (SETATTR may set, GETATTR		set). W means write-only (SETATTR may set, GETATTR
	may not retrieve). R W means read/write (GETATTR		may not retrieve). R W means read/write (GETATTR
	may retrieve, SETATTR may set).		may retrieve, SETATTR may set).</dd>
			<dt>Defined in:</dt><dd>The section of this specification that describ
	</t>		es the
	<t>Defined in: The section of this specification that describes the		attribute.</dd>
	attribute.</t>		</dl>
	</list>		<table anchor="req_attr_table" align="center">
	</t>		<thead>
			<tr>
	<texttable anchor="req_attr_table">		<th align="left">Name</th>
	<ttcol align='left' >Name</ttcol>		<th align="left">Id</th>
	<ttcol align='left' >Id</ttcol>		<th align="left">Data Type</th>
	<ttcol align='left' >Data Type</ttcol>		<th align="left">Acc</th>
	<ttcol align='left' >Acc</ttcol>		<th align="left">Defined in:</th>
	<ttcol align='left' >Defined in:</ttcol>		</tr>
			</thead>
	<c>supported_attrs</c><c>0</c><c>bitmap4</c><c>R</c>		<tbody>
	<c>		<tr>
	<xref target="attrdef_supp_attr" />		<td align="left">supported_attrs</td>
	</c>		<td align="left">0</td>
			<td align="left">bitmap4</td>
	<c>type</c><c>1</c><c>nfs_ftype4</c><c>R</c>		<td align="left">R</td>
	<c>		<td align="left">
	<xref target="attrdef_type" />		<xref target="attrdef_supp_attr" format="default"/>
	</c>		</td>
			</tr>
	<c>fh_expire_type</c><c>2</c><c>uint32_t</c><c>R</c>		<tr>
	<c>		<td align="left">type</td>
	<xref target="attrdef_fh_expire_type" />		<td align="left">1</td>
	</c>		<td align="left">nfs_ftype4</td>
			<td align="left">R</td>
	<c>change</c><c>3</c><c>uint64_t</c><c>R</c>		<td align="left">
	<c>		<xref target="attrdef_type" format="default"/>
	<xref target="attrdef_change" />		</td>
	</c>		</tr>
			<tr>
	<c>size</c><c>4</c><c>uint64_t</c><c>R W</c>		<td align="left">fh_expire_type</td>
	<c>		<td align="left">2</td>
	<xref target="attrdef_size" />		<td align="left">uint32_t</td>
	</c>		<td align="left">R</td>
			<td align="left">
	<c>link_support</c><c>5</c><c>bool</c><c>R</c>		<xref target="attrdef_fh_expire_type" format="default"/>
	<c>		</td>
	<xref target="attrdef_link_support" />		</tr>
	</c>		<tr>
			<td align="left">change</td>
	<c>symlink_support</c><c>6</c><c>bool</c><c>R</c>		<td align="left">3</td>
	<c>		<td align="left">uint64_t</td>
	<xref target="attrdef_symlink_support" />		<td align="left">R</td>
	</c>		<td align="left">
			<xref target="attrdef_change" format="default"/>
	<c>named_attr</c><c>7</c><c>bool</c><c>R</c>		</td>
	<c>		</tr>
	<xref target="attrdef_named_attr" />		<tr>
	</c>		<td align="left">size</td>
			<td align="left">4</td>
	<c>fsid</c><c>8</c><c>fsid4</c><c>R</c>		<td align="left">uint64_t</td>
	<c>		<td align="left">R W</td>
	<xref target="attrdef_fsid" />		<td align="left">
	</c>		<xref target="attrdef_size" format="default"/>
			</td>
	<c>unique_handles</c><c>9</c><c>bool</c><c>R</c>		</tr>
	<c>		<tr>
	<xref target="attrdef_unique_handles" />		<td align="left">link_support</td>
	</c>		<td align="left">5</td>
			<td align="left">bool</td>
	<c>lease_time</c><c>10</c><c>nfs_lease4</c><c>R</c>		<td align="left">R</td>
	<c>		<td align="left">
	<xref target="attrdef_lease_time" />		<xref target="attrdef_link_support" format="default"/>
	</c>		</td>
			</tr>
	<c>rdattr_error</c><c>11</c><c>enum</c><c>R</c>		<tr>
	<c>		<td align="left">symlink_support</td>
	<xref target="attrdef_rdattr_error" />		<td align="left">6</td>
	</c>		<td align="left">bool</td>
			<td align="left">R</td>
	<c>filehandle</c><c>19</c><c>nfs_fh4</c><c>R</c>		<td align="left">
	<c>		<xref target="attrdef_symlink_support" format="default"/>
	<xref target="attrdef_filehandle" />		</td>
	</c>		</tr>
			<tr>
	<c>suppattr_exclcreat</c><c>75</c><c>bitmap4</c><c>R</c>		<td align="left">named_attr</td>
	<c>		<td align="left">7</td>
	<xref target="attrdef_suppattr_exclcreat" />		<td align="left">bool</td>
	</c>		<td align="left">R</td>
			<td align="left">
	</texttable>		<xref target="attrdef_named_attr" format="default"/>
	</section>		</td>
	<section anchor="recommended_attributes"		</tr>
	title="RECOMMENDED Attributes - List and Definition References">		<tr>
	<t>		<td align="left">fsid</td>
	The RECOMMENDED attributes are defined in		<td align="left">8</td>
	<xref target="rec_attr_tbl"/>. The meanings		<td align="left">fsid4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_fsid" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">unique_handles</td>
			<td align="left">9</td>
			<td align="left">bool</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_unique_handles" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">lease_time</td>
			<td align="left">10</td>
			<td align="left">nfs_lease4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_lease_time" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">rdattr_error</td>
			<td align="left">11</td>
			<td align="left">enum</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_rdattr_error" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">filehandle</td>
			<td align="left">19</td>
			<td align="left">nfs_fh4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_filehandle" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">suppattr_exclcreat</td>
			<td align="left">75</td>
			<td align="left">bitmap4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_suppattr_exclcreat" format="default"/>
			</td>
			</tr>
			</tbody>
			</table>
			</section>
			<section anchor="recommended_attributes" numbered="true" toc="default">
			<name><bcp14>RECOMMENDED</bcp14> Attributes - List and Definition Refere
			nces</name>
			<t>
			The <bcp14>RECOMMENDED</bcp14> attributes are defined in
			<xref target="rec_attr_tbl" format="default"/>. The meanings
	of the column headers are the same as		of the column headers are the same as
	<xref target="req_attr_table"/>; see <xref		<xref target="req_attr_table" format="default"/>; see <xref target="mandato
	target="mandatory_attributes" /> for the meanings.		ry_attributes" format="default"/> for the meanings.
	</t>
	<texttable anchor="rec_attr_tbl">
	<ttcol align='left' >Name</ttcol>
	<ttcol align='left' >Id</ttcol>
	<ttcol align='left' >Data Type</ttcol>
	<ttcol align='left' >Acc</ttcol>
	<ttcol align='left' >Defined in:</ttcol>
	<c>acl</c><c>12</c><c>nfsace4&lt;></c><c>R W</c>
	<c>
	<xref target="attrdef_acl" />
	</c>
	<c>aclsupport</c><c>13</c><c>uint32_t</c><c>R</c>
	<c>
	<xref target="attrdef_aclsupport" />
	</c>
	<c>archive</c><c>14</c><c>bool</c><c>R W</c>
	<c>
	<xref target="attrdef_archive" />
	</c>
	<c>cansettime</c><c>15</c><c>bool</c><c>R</c>
	<c>
	<xref target="attrdef_cansettime" />
	</c>
	<c>case_insensitive</c><c>16</c><c>bool</c><c>R</c>
	<c>
	<xref target="attrdef_case_insensitive" />
	</c>
	<c>case_preserving</c><c>17</c><c>bool</c><c>R</c>
	<c>
	<xref target="attrdef_case_preserving" />
	</c>
	<c>change_policy</c><c>60</c><c>chg_policy4</c><c>R</c>
	<c>
	<xref target="attrdef_change_policy" />
	</c>
	<c>chown_restricted</c><c>18</c><c>bool</c><c>R</c>
	<c>
	<xref target="attrdef_chown_restricted" />
	</c>
	<c>dacl</c><c>58</c><c>nfsacl41</c><c>R W</c>
	<c>
	<xref target="attrdef_dacl" />
	</c>
	<c>dir_notif_delay</c><c>56</c><c>nfstime4</c><c>R</c>
	<c>
	<xref target="attrdef_dir_notif_delay" />
	</c>
	<c>dirent_notif_delay</c><c>57</c><c>nfstime4</c><c>R</c>
	<c>
	<xref target="attrdef_dirent_notif_delay" />
	</c>
	<c>fileid</c><c>20</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_fileid" />
	</c>
	<c>files_avail</c><c>21</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_files_avail" />
	</c>
	<c>files_free</c><c>22</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_files_free" />
	</c>
	<c>files_total</c><c>23</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_files_total" />
	</c>
	<c>fs_charset_cap</c><c>76</c><c>uint32_t</c><c>R</c>
	<c>
	<xref target="attrdef_fs_charset_cap" />
	</c>
	<c>fs_layout_type</c><c>62</c><c>layouttype4&lt;></c><c>R</c>
	<c>
	<xref target="attrdef_fs_layout_type" />
	</c>
	<c>fs_locations</c><c>24</c><c>fs_locations</c><c>R</c>
	<c>
	<xref target="attrdef_fs_locations" />
	</c>
	<c>fs_locations_info</c><c>67</c><c>*</c><c>R</c>
	<c>
	<xref target="attrdef_fs_locations_info" />
	</c>
	<c>fs_status</c><c>61</c><c>fs4_status</c><c>R</c>
	<c>
	<xref target="attrdef_fs_status" />
	</c>
	<c>hidden</c><c>25</c><c>bool</c><c>R W</c>
	<c>
	<xref target="attrdef_hidden" />
	</c>
	<c>homogeneous</c><c>26</c><c>bool</c><c>R</c>
	<c>
	<xref target="attrdef_homogeneous" />
	</c>
	<c>layout_alignment</c><c>66</c><c>uint32_t</c><c>R</c>
	<c>
	<xref target="attrdef_layout_alignment" />
	</c>
	<c>layout_blksize</c><c>65</c><c>uint32_t</c><c>R</c>
	<c>
	<xref target="attrdef_layout_blksize" />
	</c>
	<c>layout_hint</c><c>63</c><c>layouthint4</c><c>&nbsp;&nbsp;W</c>
	<c>
	<xref target="attrdef_layout_hint" />
	</c>
	<c>layout_type</c><c>64</c><c>layouttype4&lt;></c><c>R</c>
	<c>
	<xref target="attrdef_layout_type" />
	</c>
	<c>maxfilesize</c><c>27</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_maxfilesize" />
	</c>
	<c>maxlink</c><c>28</c><c>uint32_t</c><c>R</c>
	<c>
	<xref target="attrdef_maxlink" />
	</c>
	<c>maxname</c><c>29</c><c>uint32_t</c><c>R</c>
	<c>
	<xref target="attrdef_maxname" />
	</c>
	<c>maxread</c><c>30</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_maxread" />
	</c>
	<c>maxwrite</c><c>31</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_maxwrite" />
	</c>
	<c>mdsthreshold</c><c>68</c><c>mdsthreshold4</c><c>R</c>
	<c>
	<xref target="attrdef_mdsthreshold" />
	</c>
	<c>mimetype</c><c>32</c><c>utf8str_cs</c><c>R W</c>
	<c>
	<xref target="attrdef_mimetype" />
	</c>
	<c>mode</c><c>33</c><c>mode4</c><c>R W</c>
	<c>
	<xref target="attrdef_mode" />
	</c>
	<c>mode_set_masked</c><c>74</c><c>mode_masked4</c><c>&nbsp;&nbsp;W</c>
	<c>
	<xref target="attrdef_mode_set_masked" />
	</c>
	<c>mounted_on_fileid</c><c>55</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_mounted_on_fileid" />
	</c>
	<c>no_trunc</c><c>34</c><c>bool</c><c>R</c>
	<c>
	<xref target="attrdef_no_trunc" />
	</c>
	<c>numlinks</c><c>35</c><c>uint32_t</c><c>R</c>
	<c>
	<xref target="attrdef_numlinks" />
	</c>
	<c>owner</c>
	<c>36</c><c>utf8str_mixed</c><c>R W</c>
	<c>
	<xref target="attrdef_owner" />
	</c>
	<c>owner_group</c>
	<c>37</c><c>utf8str_mixed</c><c>R W</c>
	<c>
	<xref target="attrdef_owner_group" />
	</c>
	<c>quota_avail_hard</c>
	<c>38</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_quota_avail_hard" />
	</c>
	<c>quota_avail_soft</c>
	<c>39</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_quota_avail_soft" />
	</c>
	<c>quota_used</c>
	<c>40</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_quota_used" />
	</c>
	<c>rawdev</c><c>41</c><c>specdata4</c><c>R</c>
	<c>
	<xref target="attrdef_rawdev" />
	</c>
	<c>retentevt_get</c><c>71</c><c>retention_get4</c><c>R</c>
	<c>
	<xref target="attrdef_retentevt_get" />
	</c>
	<c>retentevt_set</c><c>72</c><c>retention_set4</c><c>&nbsp;&nbsp;W</c>
	<c>
	<xref target="attrdef_retentevt_set" />
	</c>
	<c>retention_get</c><c>69</c><c>retention_get4</c><c>R</c>
	<c>
	<xref target="attrdef_retention_get" />
	</c>
	<c>retention_hold</c><c>73</c><c>uint64_t</c><c>R W</c>
	<c>
	<xref target="attrdef_retention_hold" />
	</c>
	<c>retention_set</c><c>70</c><c>retention_set4</c><c>&nbsp;&nbsp;W</c>
	<c>
	<xref target="attrdef_retention_set" />
	</c>
	<c>sacl</c><c>59</c><c>nfsacl41</c><c>R W</c>
	<c>
	<xref target="attrdef_sacl" />
	</c>
	<c>space_avail</c><c>42</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_space_avail" />
	</c>
	<c>space_free</c><c>43</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_space_free" />
	</c>
	<c>space_total</c><c>44</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_space_total" />
	</c>
	<c>space_used</c><c>45</c><c>uint64_t</c><c>R</c>
	<c>
	<xref target="attrdef_space_used" />
	</c>
	<c>system</c><c>46</c><c>bool</c><c>R W</c>
	<c>
	<xref target="attrdef_system" />
	</c>
	<c>time_access</c>
	<c>47</c><c>nfstime4</c><c>R</c>
	<c>
	<xref target="attrdef_time_access" />
	</c>
	<c>time_access_set</c><c>48</c><c>settime4</c><c>&nbsp;&nbsp;W</c>
	<c>
	<xref target="attrdef_time_access_set" />
	</c>
	<c>time_backup</c><c>49</c><c>nfstime4</c><c>R W</c>
	<c>
	<xref target="attrdef_time_backup" />
	</c>
	<c>time_create</c><c>50</c><c>nfstime4</c><c>R W</c>
	<c>
	<xref target="attrdef_time_create" />
	</c>
	<c>time_delta</c><c>51</c><c>nfstime4</c><c>R</c>
	<c>
	<xref target="attrdef_time_delta" />
	</c>
	<c>time_metadata</c><c>52</c><c>nfstime4</c><c>R</c>
	<c>
	<xref target="attrdef_time_metadata" />
	</c>
	<c>time_modify</c><c>53</c><c>nfstime4</c><c>R</c>
	<c>
	<xref target="attrdef_time_modify" />
	</c>
	<c>time_modify_set</c><c>54</c><c>settime4</c><c>&nbsp;&nbsp;W</c>
	<c>
	<xref target="attrdef_time_modify_set" />
	</c>
	</texttable>
	<t>* fs_locations_info4</t>
	</section>
	<section anchor="attribute_definitions" title="Attribute
	Definitions">
	<section anchor="required_attr" title="Definitions of REQUIRED Attributes">		</t>
			<table anchor="rec_attr_tbl" align="center">
			<thead>
			<tr>
			<th align="left">Name</th>
			<th align="left">Id</th>
			<th align="left">Data Type</th>
			<th align="left">Acc</th>
			<th align="left">Defined in:</th>
			</tr>
			</thead>
			<tbody>
			<tr>
			<td align="left">acl</td>
			<td align="left">12</td>
			<td align="left">nfsace4&lt;&gt;</td>
			<td align="left">R W</td>
			<td align="left">
			<xref target="attrdef_acl" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">aclsupport</td>
			<td align="left">13</td>
			<td align="left">uint32_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_aclsupport" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">archive</td>
			<td align="left">14</td>
			<td align="left">bool</td>
			<td align="left">R W</td>
			<td align="left">
			<xref target="attrdef_archive" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">cansettime</td>
			<td align="left">15</td>
			<td align="left">bool</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_cansettime" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">case_insensitive</td>
			<td align="left">16</td>
			<td align="left">bool</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_case_insensitive" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">case_preserving</td>
			<td align="left">17</td>
			<td align="left">bool</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_case_preserving" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">change_policy</td>
			<td align="left">60</td>
			<td align="left">chg_policy4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_change_policy" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">chown_restricted</td>
			<td align="left">18</td>
			<td align="left">bool</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_chown_restricted" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">dacl</td>
			<td align="left">58</td>
			<td align="left">nfsacl41</td>
			<td align="left">R W</td>
			<td align="left">
			<xref target="attrdef_dacl" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">dir_notif_delay</td>
			<td align="left">56</td>
			<td align="left">nfstime4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_dir_notif_delay" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">dirent_notif_delay</td>
			<td align="left">57</td>
			<td align="left">nfstime4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_dirent_notif_delay" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">fileid</td>
			<td align="left">20</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_fileid" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">files_avail</td>
			<td align="left">21</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_files_avail" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">files_free</td>
			<td align="left">22</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_files_free" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">files_total</td>
			<td align="left">23</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_files_total" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">fs_charset_cap</td>
			<td align="left">76</td>
			<td align="left">uint32_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_fs_charset_cap" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">fs_layout_type</td>
			<td align="left">62</td>
			<td align="left">layouttype4&lt;&gt;</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_fs_layout_type" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">fs_locations</td>
			<td align="left">24</td>
			<td align="left">fs_locations</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_fs_locations" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">fs_locations_info</td>
			<td align="left">67</td>
			<td align="left">fs_locations_info4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_fs_locations_info" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">fs_status</td>
			<td align="left">61</td>
			<td align="left">fs4_status</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_fs_status" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">hidden</td>
			<td align="left">25</td>
			<td align="left">bool</td>
			<td align="left">R W</td>
			<td align="left">
			<xref target="attrdef_hidden" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">homogeneous</td>
			<td align="left">26</td>
			<td align="left">bool</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_homogeneous" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">layout_alignment</td>
			<td align="left">66</td>
			<td align="left">uint32_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_layout_alignment" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">layout_blksize</td>
			<td align="left">65</td>
			<td align="left">uint32_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_layout_blksize" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">layout_hint</td>
			<td align="left">63</td>
			<td align="left">layouthint4</td>
			<td align="left">&nbsp;&nbsp;W</td>
			<td align="left">
			<xref target="attrdef_layout_hint" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">layout_type</td>
			<td align="left">64</td>
			<td align="left">layouttype4&lt;&gt;</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_layout_type" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">maxfilesize</td>
			<td align="left">27</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_maxfilesize" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">maxlink</td>
			<td align="left">28</td>
			<td align="left">uint32_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_maxlink" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">maxname</td>
			<td align="left">29</td>
			<td align="left">uint32_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_maxname" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">maxread</td>
			<td align="left">30</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_maxread" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">maxwrite</td>
			<td align="left">31</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_maxwrite" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">mdsthreshold</td>
			<td align="left">68</td>
			<td align="left">mdsthreshold4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_mdsthreshold" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">mimetype</td>
			<td align="left">32</td>
			<td align="left">utf8str_cs</td>
			<td align="left">R W</td>
			<td align="left">
			<xref target="attrdef_mimetype" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">mode</td>
			<td align="left">33</td>
			<td align="left">mode4</td>
			<td align="left">R W</td>
			<td align="left">
			<xref target="attrdef_mode" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">mode_set_masked</td>
			<td align="left">74</td>
			<td align="left">mode_masked4</td>
			<td align="left">&nbsp;&nbsp;W</td>
			<td align="left">
			<xref target="attrdef_mode_set_masked" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">mounted_on_fileid</td>
			<td align="left">55</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_mounted_on_fileid" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">no_trunc</td>
			<td align="left">34</td>
			<td align="left">bool</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_no_trunc" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">numlinks</td>
			<td align="left">35</td>
			<td align="left">uint32_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_numlinks" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">owner</td>
			<td align="left">36</td>
			<td align="left">utf8str_mixed</td>
			<td align="left">R W</td>
			<td align="left">
			<xref target="attrdef_owner" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">owner_group</td>
			<td align="left">37</td>
			<td align="left">utf8str_mixed</td>
			<td align="left">R W</td>
			<td align="left">
			<xref target="attrdef_owner_group" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">quota_avail_hard</td>
			<td align="left">38</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_quota_avail_hard" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">quota_avail_soft</td>
			<td align="left">39</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_quota_avail_soft" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">quota_used</td>
			<td align="left">40</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_quota_used" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">rawdev</td>
			<td align="left">41</td>
			<td align="left">specdata4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_rawdev" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">retentevt_get</td>
			<td align="left">71</td>
			<td align="left">retention_get4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_retentevt_get" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">retentevt_set</td>
			<td align="left">72</td>
			<td align="left">retention_set4</td>
			<td align="left">&nbsp;&nbsp;W</td>
			<td align="left">
			<xref target="attrdef_retentevt_set" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">retention_get</td>
			<td align="left">69</td>
			<td align="left">retention_get4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_retention_get" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">retention_hold</td>
			<td align="left">73</td>
			<td align="left">uint64_t</td>
			<td align="left">R W</td>
			<td align="left">
			<xref target="attrdef_retention_hold" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">retention_set</td>
			<td align="left">70</td>
			<td align="left">retention_set4</td>
			<td align="left">&nbsp;&nbsp;W</td>
			<td align="left">
			<xref target="attrdef_retention_set" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">sacl</td>
			<td align="left">59</td>
			<td align="left">nfsacl41</td>
			<td align="left">R W</td>
			<td align="left">
			<xref target="attrdef_sacl" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">space_avail</td>
			<td align="left">42</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_space_avail" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">space_free</td>
			<td align="left">43</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_space_free" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">space_total</td>
			<td align="left">44</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_space_total" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">space_used</td>
			<td align="left">45</td>
			<td align="left">uint64_t</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_space_used" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">system</td>
			<td align="left">46</td>
			<td align="left">bool</td>
			<td align="left">R W</td>
			<td align="left">
			<xref target="attrdef_system" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">time_access</td>
			<td align="left">47</td>
			<td align="left">nfstime4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_time_access" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">time_access_set</td>
			<td align="left">48</td>
			<td align="left">settime4</td>
			<td align="left">&nbsp;&nbsp;W</td>
			<td align="left">
			<xref target="attrdef_time_access_set" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">time_backup</td>
			<td align="left">49</td>
			<td align="left">nfstime4</td>
			<td align="left">R W</td>
			<td align="left">
			<xref target="attrdef_time_backup" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">time_create</td>
			<td align="left">50</td>
			<td align="left">nfstime4</td>
			<td align="left">R W</td>
			<td align="left">
			<xref target="attrdef_time_create" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">time_delta</td>
			<td align="left">51</td>
			<td align="left">nfstime4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_time_delta" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">time_metadata</td>
			<td align="left">52</td>
			<td align="left">nfstime4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_time_metadata" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">time_modify</td>
			<td align="left">53</td>
			<td align="left">nfstime4</td>
			<td align="left">R</td>
			<td align="left">
			<xref target="attrdef_time_modify" format="default"/>
			</td>
			</tr>
			<tr>
			<td align="left">time_modify_set</td>
			<td align="left">54</td>
			<td align="left">settime4</td>
			<td align="left">&nbsp;&nbsp;W</td>
			<td align="left">
			<xref target="attrdef_time_modify_set" format="default"/>
			</td>
			</tr>
			</tbody>
	<section toc="exclude" anchor="attrdef_supp_attr"		</table>
	title="Attribute 0: supported_attrs">		</section>
	<t>		<section anchor="attribute_definitions" numbered="true" toc="default">
	The bit vector that would retrieve all REQUIRED and		<name>Attribute Definitions</name>
	RECOMMENDED attributes that are supported for this object.		<section anchor="required_attr" numbered="true" toc="default">
			<name>Definitions of <bcp14>REQUIRED</bcp14> Attributes</name>
			<section toc="exclude" anchor="attrdef_supp_attr" numbered="true">
			<name>Attribute 0: supported_attrs</name>
			<t>
			The bit vector that would retrieve all <bcp14>REQUIRED</bcp14> and
			<bcp14>RECOMMENDED</bcp14> attributes that are supported for this object.
	The scope of this attribute applies to all objects with a		The scope of this attribute applies to all objects with a
	matching fsid.		matching fsid.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_type" numbered="true">
	<section toc="exclude" anchor="attrdef_type"		<name>Attribute 1: type</name>
	title="Attribute 1: type">		<t>
	<t>
	Designates the type of an object in terms of one of a number		Designates the type of an object in terms of one of a number
	of special constants:		of special constants:
	<list style="symbols">
	<t>
	NF4REG designates a regular file.
	</t>		</t>
	<t>		<ul spacing="normal">
			<li>
			NF4REG designates a regular file.
			</li>
			<li>
	NF4DIR designates a directory.		NF4DIR designates a directory.
	</t>		</li>
	<t>		<li>
	NF4BLK designates a block device special file.		NF4BLK designates a block device special file.
	</t>		</li>
	<t>		<li>
	NF4CHR designates a character device special file.		NF4CHR designates a character device special file.
	</t>		</li>
	<t>		<li>
	NF4LNK designates a symbolic link.		NF4LNK designates a symbolic link.
	</t>		</li>
	<t>		<li>
	NF4SOCK designates a named socket special file.		NF4SOCK designates a named socket special file.
	</t>		</li>
	<t>		<li>
	NF4FIFO designates a fifo special file.		NF4FIFO designates a fifo special file.
	</t>		</li>
	<t>		<li>
	NF4ATTRDIR designates a named attribute directory.		NF4ATTRDIR designates a named attribute directory.
	</t>		</li>
	<t>		<li>
	NF4NAMEDATTR designates a named attribute.		NF4NAMEDATTR designates a named attribute.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Within the explanatory text and operation descriptions, the		Within the explanatory text and operation descriptions, the
	following phrases will be used with the meanings given below:		following phrases will be used with the meanings given below:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The phrase "is a directory" means that the object's		The phrase "is a directory" means that the object's
	type attribute is NF4DIR or NF4ATTRDIR.		type attribute is NF4DIR or NF4ATTRDIR.
	</t>		</li>
	<t>		<li>
	The phrase "is a special file" means that the object's type		The phrase "is a special file" means that the object's type
	attribute is NF4BLK, NF4CHR, NF4SOCK, or NF4FIFO.		attribute is NF4BLK, NF4CHR, NF4SOCK, or NF4FIFO.
	</t>		</li>
	<t>		<li>
	The phrases "is an ordinary file" and		The phrases "is an ordinary file" and
	"is a regular file" mean that the object's		"is a regular file" mean that the object's
	type attribute is NF4REG or NF4NAMEDATTR.		type attribute is NF4REG or NF4NAMEDATTR.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
			<section toc="exclude" anchor="attrdef_fh_expire_type" numbered="true"
	</section>		>
			<name>Attribute 2: fh_expire_type</name>
	<section toc="exclude" anchor="attrdef_fh_expire_type"		<t>
	title="Attribute 2: fh_expire_type">
	<t>
	Server uses this to specify filehandle expiration behavior		Server uses this to specify filehandle expiration behavior
	to the client. See <xref target="Filehandles"/> for additional		to the client. See <xref target="Filehandles" format="default"/> for a dditional
	description.		description.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_change" numbered="true">
	<section toc="exclude" anchor="attrdef_change"		<name>Attribute 3: change</name>
	title="Attribute 3: change">		<t>
	<t>
	A value created by the server that the client can use to		A value created by the server that the client can use to
	determine if file data, directory contents, or attributes of		determine if file data, directory contents, or attributes of
	the object have been modified. The server may return the		the object have been modified. The server may return the
	object's time_metadata attribute for this attribute's value,		object's time_metadata attribute for this attribute's value,
	but only if the file system object cannot be updated more		but only if the file system object cannot be updated more
	frequently than the resolution of time_metadata.		frequently than the resolution of time_metadata.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_size" numbered="true">
	<section toc="exclude" anchor="attrdef_size"		<name>Attribute 4: size</name>
	title="Attribute 4: size">		<t>
	<t>
	The size of the object in bytes.		The size of the object in bytes.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_link_support" numbered="true">
	<section toc="exclude" anchor="attrdef_link_support"		<name>Attribute 5: link_support</name>
	title="Attribute 5: link_support">		<t>
	<t>
	TRUE, if the object's file system supports hard links.		TRUE, if the object's file system supports hard links.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_symlink_support" numbered="true
	<section toc="exclude" anchor="attrdef_symlink_support"		">
	title="Attribute 6: symlink_support">		<name>Attribute 6: symlink_support</name>
	<t>		<t>
	TRUE, if the object's file system supports symbolic links.		TRUE, if the object's file system supports symbolic links.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_named_attr" numbered="true">
	<section toc="exclude" anchor="attrdef_named_attr"		<name>Attribute 7: named_attr</name>
	title="Attribute 7: named_attr">		<t>
	<t>
	TRUE, if this object has named attributes. In other words,		TRUE, if this object has named attributes. In other words,
	object has a non-empty named attribute directory.		object has a non-empty named attribute directory.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_fsid" numbered="true">
	<section toc="exclude" anchor="attrdef_fsid"		<name>Attribute 8: fsid</name>
	title="Attribute 8: fsid">		<t>
	<t>
	Unique file system identifier for the file system holding this		Unique file system identifier for the file system holding this
	object. The fsid attribute has major and minor components, each of		object. The fsid attribute has major and minor components, each of
	which are of data type uint64_t.		which are of data type uint64_t.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_unique_handles" numbered="true"
	<section toc="exclude" anchor="attrdef_unique_handles"		>
	title="Attribute 9: unique_handles">		<name>Attribute 9: unique_handles</name>
	<t>		<t>
	TRUE, if two distinct filehandles are guaranteed to refer to two		TRUE, if two distinct filehandles are guaranteed to refer to two
	different file system objects.		different file system objects.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_lease_time" numbered="true">
	<section toc="exclude" anchor="attrdef_lease_time"		<name>Attribute 10: lease_time</name>
	title="Attribute 10: lease_time">		<t>
	<t>
	Duration of the lease at server in seconds.		Duration of the lease at server in seconds.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_rdattr_error" numbered="true">
	<section toc="exclude" anchor="attrdef_rdattr_error"		<name>Attribute 11: rdattr_error</name>
	title="Attribute 11: rdattr_error">		<t>
	<t>
	Error returned from an attempt to retrieve attributes during a READDIR operation.		Error returned from an attempt to retrieve attributes during a READDIR operation.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_filehandle" numbered="true">
	<section toc="exclude" anchor="attrdef_filehandle"		<name>Attribute 19: filehandle</name>
	title="Attribute 19: filehandle">		<t>
	<t>
	The filehandle of this object (primarily for READDIR requests).		The filehandle of this object (primarily for READDIR requests).
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_suppattr_exclcreat" numbered="t
	<section toc="exclude" anchor="attrdef_suppattr_exclcreat"		rue">
	title="Attribute 75: suppattr_exclcreat">		<name>Attribute 75: suppattr_exclcreat</name>
	<t>		<t>
	The bit vector that would set all REQUIRED and		The bit vector that would set all <bcp14>REQUIRED</bcp14> and
	RECOMMENDED attributes that are supported by the EXCLUSIVE4_1		<bcp14>RECOMMENDED</bcp14> attributes that are supported by the EXCLUSIVE
			4_1
	method of file creation via the OPEN operation.		method of file creation via the OPEN operation.
	The scope of this attribute applies to all objects with a		The scope of this attribute applies to all objects with a
	matching fsid.		matching fsid.
	</t>		</t>
	</section>		</section>
			</section>
	</section>		<section anchor="recommended_attr" numbered="true" toc="default">
			<name>Definitions of Uncategorized <bcp14>RECOMMENDED</bcp14> Attribut
	<section anchor="recommended_attr" title="Definitions of Uncategorized RECOMM		es</name>
	ENDED Attributes">		<t>
	<t>		The definitions of most of the <bcp14>RECOMMENDED</bcp14> attributes follow
	The definitions of most of the RECOMMENDED attributes follow. Collections		. Collections
	that share a common category are defined in other sections.		that share a common category are defined in other sections.
	</t>		</t>
			<section toc="exclude" anchor="attrdef_archive" numbered="true">
	<section toc="exclude" anchor="attrdef_archive"		<name>Attribute 14: archive</name>
	title="Attribute 14: archive">		<t>
	<t>
	TRUE, if this file has been archived since the time of last		TRUE, if this file has been archived since the time of last
	modification (deprecated in favor of time_backup).		modification (deprecated in favor of time_backup).
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_cansettime" numbered="true">
	<section toc="exclude" anchor="attrdef_cansettime"		<name>Attribute 15: cansettime</name>
	title="Attribute 15: cansettime">		<t>
	<t>
	TRUE, if the server is able to change the times for a		TRUE, if the server is able to change the times for a
	file system object as specified in a SETATTR operation.		file system object as specified in a SETATTR operation.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_case_insensitive" numbered="tru
	<section toc="exclude" anchor="attrdef_case_insensitive"		e">
	title="Attribute 16: case_insensitive">		<name>Attribute 16: case_insensitive</name>
	<t>		<t>
	TRUE, if file name comparisons on this file system are case		TRUE, if file name comparisons on this file system are case
	insensitive.		insensitive.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_case_preserving" numbered="true
	<section toc="exclude" anchor="attrdef_case_preserving"		">
	title="Attribute 17: case_preserving">		<name>Attribute 17: case_preserving</name>
	<t>		<t>
	TRUE, if file name case on this file system is preserved.		TRUE, if file name case on this file system is preserved.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_change_policy" numbered="true">
	<section toc="exclude" anchor="attrdef_change_policy"		<name>Attribute 60: change_policy</name>
	title="Attribute 60: change_policy">		<t>
	<t>
	A value created by the server that the client can use to		A value created by the server that the client can use to
	determine if some server policy related to the current		determine if some server policy related to the current
	file system has been subject to change. If the value		file system has been subject to change. If the value
	remains the same, then the client can be sure that the		remains the same, then the client can be sure that the
	values of the attributes related to fs location		values of the attributes related to fs location
	and the fss_type field of the fs_status attribute have		and the fss_type field of the fs_status attribute have
	not changed. On the other hand, a change in this value does		not changed. On the other hand, a change in this value does
	necessarily imply a change in policy. It is up to the client		necessarily imply a change in policy. It is up to the client
	to interrogate the server to determine if some policy relevant to		to interrogate the server to determine if some policy relevant to
	it has changed. See <xref target="chg_policy4" /> for		it has changed. See <xref target="chg_policy4" format="default"/> for
	details.		details.
	</t>		</t>
	<t>		<t>
	This attribute MUST change when the value returned by		This attribute <bcp14>MUST</bcp14> change when the value returned by
	the fs_locations or fs_locations_info attribute changes, when		the fs_locations or fs_locations_info attribute changes, when
	a file system goes from read-only to writable or vice versa,		a file system goes from read-only to writable or vice versa,
	or when the allowable set of security flavors for the file system		or when the allowable set of security flavors for the file system
	or any part thereof is changed.		or any part thereof is changed.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_chown_restricted" numbered="tru
	<section toc="exclude" anchor="attrdef_chown_restricted"		e">
	title="Attribute 18: chown_restricted">		<name>Attribute 18: chown_restricted</name>
	<t>		<t>
	If TRUE, the server will reject any request to change either		If TRUE, the server will reject any request to change either
	the owner or the group associated with a file if the caller		the owner or the group associated with a file if the caller
	is not a privileged user (for example, "root" in UNIX		is not a privileged user (for example, "root" in UNIX
	operating environments or, in Windows 2000, the "Take		operating environments or, in Windows 2000, the "Take
	Ownership" privilege).		Ownership" privilege).
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_fileid" numbered="true">
	<section toc="exclude" anchor="attrdef_fileid"		<name>Attribute 20: fileid</name>
	title="Attribute 20: fileid">		<t>
	<t>
	A number uniquely identifying the file within the file system.		A number uniquely identifying the file within the file system.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_files_avail" numbered="true">
	<section toc="exclude" anchor="attrdef_files_avail"		<name>Attribute 21: files_avail</name>
	title="Attribute 21: files_avail">		<t>
	<t>
	File slots available to this user on the file system		File slots available to this user on the file system
	containing this object -- this should be the smallest		containing this object -- this should be the smallest
	relevant limit.		relevant limit.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_files_free" numbered="true">
	<section toc="exclude" anchor="attrdef_files_free"		<name>Attribute 22: files_free</name>
	title="Attribute 22: files_free">		<t>
	<t>
	Free file slots on the file system containing this object --		Free file slots on the file system containing this object --
	this should be the smallest relevant limit.		this should be the smallest relevant limit.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_files_total" numbered="true">
	<section toc="exclude" anchor="attrdef_files_total"		<name>Attribute 23: files_total</name>
	title="Attribute 23: files_total">		<t>
	<t>
	Total file slots on the file system containing this object.		Total file slots on the file system containing this object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_fs_charset_cap" numbered="true"
	<section toc="exclude" anchor="attrdef_fs_charset_cap"		>
	title="Attribute 76: fs_charset_cap">		<name>Attribute 76: fs_charset_cap</name>
	<t>		<t>
	Character set capabilities for this file system. See		Character set capabilities for this file system. See
	<xref target="utf8_caps"/>.		<xref target="utf8_caps" format="default"/>.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_fs_locations" numbered="true">
	<section toc="exclude" anchor="attrdef_fs_locations"		<name>Attribute 24: fs_locations</name>
	title="Attribute 24: fs_locations">		<t>
	<t>
	Locations where this file system may be found. If the server		Locations where this file system may be found. If the server
	returns NFS4ERR_MOVED as an error, this attribute MUST be		returns NFS4ERR_MOVED as an error, this attribute <bcp14>MUST</bcp14> be
	supported.		supported.
	See <xref target="fs_locations"/> for more details.		See <xref target="fs_locations" format="default"/> for more details.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_fs_locations_info" numbered="tr
	<section toc="exclude" anchor="attrdef_fs_locations_info"		ue">
	title="Attribute 67: fs_locations_info">		<name>Attribute 67: fs_locations_info</name>
	<t>		<t>
	Full function file system location.		Full function file system location.
	See <xref target="SEC11-fsli-info"/> for more details.		See <xref target="SEC11-fsli-info" format="default"/> for more details.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_fs_status" numbered="true">
	<section toc="exclude" anchor="attrdef_fs_status"		<name>Attribute 61: fs_status</name>
	title="Attribute 61: fs_status">		<t>
	<t>
	Generic file system type information.		Generic file system type information.
	See <xref target="fs_status"/> for more details.		See <xref target="fs_status" format="default"/> for more details.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_hidden" numbered="true">
	<section toc="exclude" anchor="attrdef_hidden"		<name>Attribute 25: hidden</name>
	title="Attribute 25: hidden">		<t>
	<t>
	TRUE, if the file is considered hidden with respect to		TRUE, if the file is considered hidden with respect to
	the Windows API.		the Windows API.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_homogeneous" numbered="true">
	<section toc="exclude" anchor="attrdef_homogeneous"		<name>Attribute 26: homogeneous</name>
	title="Attribute 26: homogeneous">		<t>
	<t>
	TRUE, if this object's file system is homogeneous; i.e., all		TRUE, if this object's file system is homogeneous; i.e., all
	objects in the file system (all objects on the server with the		objects in the file system (all objects on the server with the
	same fsid) have common values for all per-file-system attributes.		same fsid) have common values for all per-file-system attributes.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_maxfilesize" numbered="true">
	<section toc="exclude" anchor="attrdef_maxfilesize"		<name>Attribute 27: maxfilesize</name>
	title="Attribute 27: maxfilesize">		<t>
	<t>
	Maximum supported file size for the file system of this object.		Maximum supported file size for the file system of this object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_maxlink" numbered="true">
	<section toc="exclude" anchor="attrdef_maxlink"		<name>Attribute 28: maxlink</name>
	title="Attribute 28: maxlink">		<t>
	<t>
	Maximum number of links for this object.		Maximum number of links for this object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_maxname" numbered="true">
	<section toc="exclude" anchor="attrdef_maxname"		<name>Attribute 29: maxname</name>
	title="Attribute 29: maxname">		<t>
	<t>
	Maximum file name size supported for this object.		Maximum file name size supported for this object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_maxread" numbered="true">
	<section toc="exclude" anchor="attrdef_maxread"		<name>Attribute 30: maxread</name>
	title="Attribute 30: maxread">		<t>
	<t>
	Maximum amount of data the READ operation will return for this object.		Maximum amount of data the READ operation will return for this object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_maxwrite" numbered="true">
	<section toc="exclude" anchor="attrdef_maxwrite"		<name>Attribute 31: maxwrite</name>
	title="Attribute 31: maxwrite">		<t>
	<t>
	Maximum amount of data the WRITE operation will accept for this object.		Maximum amount of data the WRITE operation will accept for this object.
	This		This
	attribute SHOULD be supported if the file is writable. Lack		attribute <bcp14>SHOULD</bcp14> be supported if the file is writable. La ck
	of this attribute can lead to the client either wasting		of this attribute can lead to the client either wasting
	bandwidth or not receiving the best performance.		bandwidth or not receiving the best performance.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_mimetype" numbered="true">
	<section toc="exclude" anchor="attrdef_mimetype"		<name>Attribute 32: mimetype</name>
	title="Attribute 32: mimetype">		<t>
	<t>
	MIME body type/subtype of this object.		MIME body type/subtype of this object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_mounted_on_fileid" numbered="tr
	<section toc="exclude" anchor="attrdef_mounted_on_fileid"		ue">
	title="Attribute 55: mounted_on_fileid">		<name>Attribute 55: mounted_on_fileid</name>
	<t>		<t>
	Like fileid, but if the target filehandle is the root of a		Like fileid, but if the target filehandle is the root of a
	file system, this attribute represents the fileid of the		file system, this attribute represents the fileid of the
	underlying directory.		underlying directory.
	</t>		</t>
	<t>		<t>
	UNIX-based operating environments connect a file system into		UNIX-based operating environments connect a file system into
	the namespace by connecting (mounting) the file system onto		the namespace by connecting (mounting) the file system onto
	the existing file object (the mount point, usually a		the existing file object (the mount point, usually a
	directory) of an existing file system. When the mount point's		directory) of an existing file system. When the mount point's
	parent directory is read via an API like readdir(), the return		parent directory is read via an API like readdir(), the return
	results are directory entries, each with a component name and		results are directory entries, each with a component name and
	a fileid. The fileid of the mount point's directory entry will		a fileid. The fileid of the mount point's directory entry will
	be different from the fileid that the stat() system call		be different from the fileid that the stat() system call
	returns. The stat() system call is returning the fileid of the		returns. The stat() system call is returning the fileid of the
	root of the mounted file system, whereas readdir() is		root of the mounted file system, whereas readdir() is
	returning the fileid that stat() would have returned before any		returning the fileid that stat() would have returned before any
	file systems were mounted on the mount point.		file systems were mounted on the mount point.
	</t>		</t>
	<t>		<t>
	Unlike NFSv3, NFSv4.1 allows a client's LOOKUP		Unlike NFSv3, NFSv4.1 allows a client's LOOKUP
	request to cross other file systems. The client detects the		request to cross other file systems. The client detects the
	file system crossing whenever the filehandle argument of		file system crossing whenever the filehandle argument of
	LOOKUP has an fsid attribute different from that of the		LOOKUP has an fsid attribute different from that of the
	filehandle returned by LOOKUP. A UNIX-based client will		filehandle returned by LOOKUP. A UNIX-based client will
	consider this a "mount point crossing". UNIX has a legacy		consider this a "mount point crossing". UNIX has a legacy
	scheme for allowing a process to determine its current working		scheme for allowing a process to determine its current working
	directory. This relies on readdir() of a mount point's parent		directory. This relies on readdir() of a mount point's parent
	and stat() of the mount point returning fileids as previously		and stat() of the mount point returning fileids as previously
	described. The mounted_on_fileid attribute corresponds to the		described. The mounted_on_fileid attribute corresponds to the
	fileid that readdir() would have returned as described		fileid that readdir() would have returned as described
	previously.		previously.
	</t>		</t>
	<t>		<t>
	While the NFSv4.1 client could simply fabricate a fileid		While the NFSv4.1 client could simply fabricate a fileid
	corresponding to what mounted_on_fileid provides (and if the		corresponding to what mounted_on_fileid provides (and if the
	server does not support mounted_on_fileid, the client has no		server does not support mounted_on_fileid, the client has no
	choice), there is a risk that the client will generate a		choice), there is a risk that the client will generate a
	fileid that conflicts with one that is already assigned to		fileid that conflicts with one that is already assigned to
	another object in the file system. Instead, if the server can		another object in the file system. Instead, if the server can
	provide the mounted_on_fileid, the potential for client		provide the mounted_on_fileid, the potential for client
	operational problems in this area is eliminated.		operational problems in this area is eliminated.
	</t>		</t>
	<t>		<t>
	If the server detects that there is no mounted point at the		If the server detects that there is no mounted point at the
	target file object, then the value for mounted_on_fileid that		target file object, then the value for mounted_on_fileid that
	it returns is the same as that of the fileid attribute.		it returns is the same as that of the fileid attribute.
	</t>		</t>
	<t>		<t>
	The mounted_on_fileid attribute is RECOMMENDED, so the server		The mounted_on_fileid attribute is <bcp14>RECOMMENDED</bcp14>, so the ser
	SHOULD provide it if possible, and for a UNIX-based server,		ver
			<bcp14>SHOULD</bcp14> provide it if possible, and for a UNIX-based server
			,
	this is straightforward. Usually, mounted_on_fileid will be		this is straightforward. Usually, mounted_on_fileid will be
	requested during a READDIR operation, in which case it is		requested during a READDIR operation, in which case it is
	trivial (at least for UNIX-based servers) to return		trivial (at least for UNIX-based servers) to return
	mounted_on_fileid since it is equal to the fileid of a		mounted_on_fileid since it is equal to the fileid of a
	directory entry returned by readdir(). If mounted_on_fileid		directory entry returned by readdir(). If mounted_on_fileid
	is requested in a GETATTR operation, the server should obey an		is requested in a GETATTR operation, the server should obey an
	invariant that has it returning a value that is equal to the		invariant that has it returning a value that is equal to the
	file object's entry in the object's parent directory,		file object's entry in the object's parent directory,
	i.e., what readdir() would have returned. Some operating		i.e., what readdir() would have returned. Some operating
	environments allow a series of two or more file systems to be		environments allow a series of two or more file systems to be
	mounted onto a single mount point. In this case, for the		mounted onto a single mount point. In this case, for the
	server to obey the aforementioned invariant, it will need to		server to obey the aforementioned invariant, it will need to
	find the base mount point, and not the intermediate mount		find the base mount point, and not the intermediate mount
	points.		points.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_no_trunc" numbered="true">
	<section toc="exclude" anchor="attrdef_no_trunc"		<name>Attribute 34: no_trunc</name>
	title="Attribute 34: no_trunc">		<t>
	<t>
	If this attribute is TRUE, then if the client uses a file		If this attribute is TRUE, then if the client uses a file
	name longer than name_max, an error will be		name longer than name_max, an error will be
	returned instead of the name being truncated.		returned instead of the name being truncated.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_numlinks" numbered="true">
	<section toc="exclude" anchor="attrdef_numlinks"		<name>Attribute 35: numlinks</name>
	title="Attribute 35: numlinks">		<t>
	<t>
	Number of hard links to this object.		Number of hard links to this object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_owner" numbered="true">
	<section toc="exclude" anchor="attrdef_owner"		<name>Attribute 36: owner</name>
	title="Attribute 36: owner">		<t>
	<t>
	The string name of the owner of this object.		The string name of the owner of this object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_owner_group" numbered="true">
	<section toc="exclude" anchor="attrdef_owner_group"		<name>Attribute 37: owner_group</name>
	title="Attribute 37: owner_group">		<t>
	<t>
	The string name of the group ownership of this object.		The string name of the group ownership of this object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_quota_avail_hard" numbered="tru
	<section toc="exclude" anchor="attrdef_quota_avail_hard"		e">
	title="Attribute 38: quota_avail_hard">		<name>Attribute 38: quota_avail_hard</name>
	<t anchor="quota_avail_hard">		<t anchor="quota_avail_hard">
	The value in bytes that represents the amount of additional		The value in bytes that represents the amount of additional
	disk space beyond the current allocation that can be allocated		disk space beyond the current allocation that can be allocated
	to this file or directory before further allocations will be		to this file or directory before further allocations will be
	refused. It is understood that this space may be consumed by		refused. It is understood that this space may be consumed by
	allocations to other files or directories.		allocations to other files or directories.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_quota_avail_soft" numbered="tru
	<section toc="exclude" anchor="attrdef_quota_avail_soft"		e">
	title="Attribute 39: quota_avail_soft">		<name>Attribute 39: quota_avail_soft</name>
	<t anchor="quota_avail_soft">		<t anchor="quota_avail_soft">
	The value in bytes that represents the amount of additional		The value in bytes that represents the amount of additional
	disk space that can be allocated to this file or directory		disk space that can be allocated to this file or directory
	before the user may reasonably be warned. It is understood		before the user may reasonably be warned. It is understood
	that this space may be consumed by allocations to other files		that this space may be consumed by allocations to other files
	or directories though there is a rule as to which other files		or directories though there is a rule as to which other files
	or directories.		or directories.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_quota_used" numbered="true">
	<section toc="exclude" anchor="attrdef_quota_used"		<name>Attribute 40: quota_used</name>
	title="Attribute 40: quota_used">		<t anchor="quota_used">
	<t anchor="quota_used">
	The value in bytes that represents the amount of disk		The value in bytes that represents the amount of disk
	space used by this file or directory and possibly a		space used by this file or directory and possibly a
	number of other similar files or directories, where the		number of other similar files or directories, where the
	set of "similar" meets at least the criterion that		set of "similar" meets at least the criterion that
	allocating space to any file or directory in the set		allocating space to any file or directory in the set
	will reduce the "quota_avail_hard" of every other file		will reduce the "quota_avail_hard" of every other file
	or directory in the set.		or directory in the set.
	<vspace blankLines='1' />		</t>
			<t>
	Note that there may be a number of distinct but		Note that there may be a number of distinct but
	overlapping sets of files or directories for which a		overlapping sets of files or directories for which a
	quota_used value is maintained, e.g., "all files with a		quota_used value is maintained, e.g., "all files with a
	given owner", "all files with a given group owner", etc.		given owner", "all files with a given group owner", etc.
	The server is at liberty to choose any of those sets when		The server is at liberty to choose any of those sets when
	providing the content of the quota_used attribute, but		providing the content of the quota_used attribute, but
	should do so in a repeatable way. The rule may be		should do so in a repeatable way. The rule may be
	configured per file system or may be "choose the set with		configured per file system or may be "choose the set with
	the smallest quota".		the smallest quota".
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_rawdev" numbered="true">
	<section toc="exclude" anchor="attrdef_rawdev"		<name>Attribute 41: rawdev</name>
	title="Attribute 41: rawdev">		<t>
	<t>
	Raw device number of file of type NF4BLK or NF4CHR. The device		Raw device number of file of type NF4BLK or NF4CHR. The device
	number is split into major and minor numbers.		number is split into major and minor numbers.
	If the file's type attribute is not NF4BLK or NF4CHR,		If the file's type attribute is not NF4BLK or NF4CHR,
	the value returned SHOULD NOT be considered useful.		the value returned <bcp14>SHOULD NOT</bcp14> be considered useful.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_space_avail" numbered="true">
	<section toc="exclude" anchor="attrdef_space_avail"		<name>Attribute 42: space_avail</name>
	title="Attribute 42: space_avail">		<t>
	<t>
	Disk space in bytes available to this user on the file system		Disk space in bytes available to this user on the file system
	containing this object -- this should be the smallest		containing this object -- this should be the smallest
	relevant limit.		relevant limit.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_space_free" numbered="true">
	<section toc="exclude" anchor="attrdef_space_free"		<name>Attribute 43: space_free</name>
	title="Attribute 43: space_free">		<t>
	<t>
	Free disk space in bytes on the file system containing this		Free disk space in bytes on the file system containing this
	object -- this should be the smallest relevant limit.		object -- this should be the smallest relevant limit.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_space_total" numbered="true">
	<section toc="exclude" anchor="attrdef_space_total"		<name>Attribute 44: space_total</name>
	title="Attribute 44: space_total">		<t>
	<t>
	Total disk space in bytes on the file system containing this object.		Total disk space in bytes on the file system containing this object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_space_used" numbered="true">
	<section toc="exclude" anchor="attrdef_space_used"		<name>Attribute 45: space_used</name>
	title="Attribute 45: space_used">		<t>
	<t>
	Number of file system bytes allocated to this object.		Number of file system bytes allocated to this object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_system" numbered="true">
	<section toc="exclude" anchor="attrdef_system"		<name>Attribute 46: system</name>
	title="Attribute 46: system">		<t>
	<t>
	This attribute is TRUE if this file is a "system" file with		This attribute is TRUE if this file is a "system" file with
	respect to the Windows operating environment.		respect to the Windows operating environment.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_time_access" numbered="true">
	<section toc="exclude" anchor="attrdef_time_access"		<name>Attribute 47: time_access</name>
	title="Attribute 47: time_access">		<t>
	<t>
	The time_access attribute represents the time of last access to		The time_access attribute represents the time of last access to
	the object by a READ operation sent to the server. The notion		the object by a READ operation sent to the server. The notion
	of what is an "access" depends on the server's operating environment		of what is an "access" depends on the server's operating environment
	and/or the server's file system semantics. For example, for		and/or the server's file system semantics. For example, for
	servers obeying Portable Operating System Interface (POSIX) semantics, ti me_access would be updated only		servers obeying Portable Operating System Interface (POSIX) semantics, ti me_access would be updated only
	by the READ and READDIR operations and not any of the operations		by the READ and READDIR operations and not any of the operations
	that modify the content of the object <xref target="read_atime"/>,		that modify the content of the object <xref target="read_atime" format="d
	<xref target="readdir_atime"/>, <xref target="write_atime"/>. Of		efault"/>,
			<xref target="readdir_atime" format="default"/>, <xref target="write_atim
			e" format="default"/>. Of
	course, setting the corresponding time_access_set attribute is		course, setting the corresponding time_access_set attribute is
	another way to modify the time_access attribute.		another way to modify the time_access attribute.
	</t>		</t>
	<t>		<t>
	Whenever the file object resides on a writable file system,		Whenever the file object resides on a writable file system,
	the server should make its best efforts to record time_access into		the server should make its best efforts to record time_access into
	stable storage. However, to mitigate the performance effects		stable storage. However, to mitigate the performance effects
	of doing so, and most especially whenever the server is		of doing so, and most especially whenever the server is
	satisfying the read of the object's content from its cache,		satisfying the read of the object's content from its cache,
	the server MAY cache access time updates and lazily write them		the server <bcp14>MAY</bcp14> cache access time updates and lazily write them
	to stable storage. It is also acceptable to give		to stable storage. It is also acceptable to give
	administrators of the server the option to disable time_access		administrators of the server the option to disable time_access
	updates.		updates.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_time_access_set" numbered="true
	<section toc="exclude" anchor="attrdef_time_access_set"		">
	title="Attribute 48: time_access_set">		<name>Attribute 48: time_access_set</name>
	<t>		<t>
	Sets the time of last access to the object. SETATTR use only.		Sets the time of last access to the object. SETATTR use only.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_time_backup" numbered="true">
	<section toc="exclude" anchor="attrdef_time_backup"		<name>Attribute 49: time_backup</name>
	title="Attribute 49: time_backup">		<t>
	<t>
	The time of last backup of the object.		The time of last backup of the object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_time_create" numbered="true">
	<section toc="exclude" anchor="attrdef_time_create"		<name>Attribute 50: time_create</name>
	title="Attribute 50: time_create">		<t>
	<t>
	The time of creation of the object. This attribute does not		The time of creation of the object. This attribute does not
	have any relation to the traditional UNIX file attribute		have any relation to the traditional UNIX file attribute
	"ctime" or "change time".		"ctime" or "change time".
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_time_delta" numbered="true">
	<section toc="exclude" anchor="attrdef_time_delta"		<name>Attribute 51: time_delta</name>
	title="Attribute 51: time_delta">		<t>
	<t>
	Smallest useful server time granularity.		Smallest useful server time granularity.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_time_metadata" numbered="true">
	<section toc="exclude" anchor="attrdef_time_metadata"		<name>Attribute 52: time_metadata</name>
	title="Attribute 52: time_metadata">		<t>
	<t>
	The time of last metadata modification of the object.		The time of last metadata modification of the object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_time_modify" numbered="true">
	<section toc="exclude" anchor="attrdef_time_modify"		<name>Attribute 53: time_modify</name>
	title="Attribute 53: time_modify">		<t>
	<t>
	The time of last modification to the object.		The time of last modification to the object.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_time_modify_set" numbered="true
	<section toc="exclude" anchor="attrdef_time_modify_set"		">
	title="Attribute 54: time_modify_set">		<name>Attribute 54: time_modify_set</name>
	<t>		<t>
	Sets the time of last modification to the object. SETATTR use only.		Sets the time of last modification to the object. SETATTR use only.
	</t>		</t>
	</section>		</section>
			</section>
	</section>		</section>
			<section anchor="owner_owner_group" numbered="true" toc="default">
	</section>		<name>Interpreting owner and owner_group</name>
			<t>
	<section anchor="owner_owner_group"		The <bcp14>RECOMMENDED</bcp14> attributes "owner" and "owner_group" (and a
	title="Interpreting owner and owner_group">		lso
	<t>
	The RECOMMENDED attributes "owner" and "owner_group" (and also
	users and groups within the "acl" attribute) are represented in		users and groups within the "acl" attribute) are represented in
	terms of a UTF-8 string. To avoid a representation that is tied		terms of a UTF-8 string. To avoid a representation that is tied
	to a particular underlying implementation at the client or		to a particular underlying implementation at the client or
	server, the use of the UTF-8 string has been chosen. Note that		server, the use of the UTF-8 string has been chosen. Note that
	Section 6.1 of <xref target="RFC2624">RFC 2624</xref> provides		Section <xref target="RFC2624" sectionFormat="bare" section="6.1"/>
			of RFC 2624 <xref target="RFC2624" format="default"/> provides
	additional rationale. It is expected that the client and server		additional rationale. It is expected that the client and server
	will have their own local representation of owner and		will have their own local representation of owner and
	owner_group that is used for local storage or presentation to		owner_group that is used for local storage or presentation to
	the end user. Therefore, it is expected that when these		the end user. Therefore, it is expected that when these
	attributes are transferred between the client and server,		attributes are transferred between the client and server,
	the local representation is translated to a syntax of the form		the local representation is translated to a syntax of the form
	"user@dns_domain". This will allow for a client and server that		"user@dns_domain". This will allow for a client and server that
	do not use the same local representation the ability to		do not use the same local representation the ability to
	translate to a common syntax that can be interpreted by both.		translate to a common syntax that can be interpreted by both.
	</t>		</t>
	<t>		<t>
	Similarly, security principals may be represented in different		Similarly, security principals may be represented in different
	ways by different security mechanisms. Servers normally		ways by different security mechanisms. Servers normally
	translate these representations into a common format,		translate these representations into a common format,
	generally that used by local storage, to serve as a means of		generally that used by local storage, to serve as a means of
	identifying the users corresponding to these security		identifying the users corresponding to these security
	principals. When these local identifiers are translated to		principals. When these local identifiers are translated to
	the form of the owner attribute, associated with files created		the form of the owner attribute, associated with files created
	by such principals, they identify, in a common format, the		by such principals, they identify, in a common format, the
	users associated with each corresponding set of security		users associated with each corresponding set of security
	principals.		principals.
	</t>		</t>
	<t>		<t>
	The translation used to interpret owner and group strings is		The translation used to interpret owner and group strings is
	not specified as part of the protocol. This allows various		not specified as part of the protocol. This allows various
	solutions to be employed. For example, a local translation		solutions to be employed. For example, a local translation
	table may be consulted that maps a numeric identifier to the		table may be consulted that maps a numeric identifier to the
	user@dns_domain syntax. A name service may also be used to		user@dns_domain syntax. A name service may also be used to
	accomplish the translation. A server may provide a more		accomplish the translation. A server may provide a more
	general service, not limited by any particular translation		general service, not limited by any particular translation
	(which would only translate a limited set of possible strings)		(which would only translate a limited set of possible strings)
	by storing the owner and owner_group attributes in local		by storing the owner and owner_group attributes in local
	storage without any translation or it may augment a		storage without any translation or it may augment a
	translation method by storing the entire string for attributes		translation method by storing the entire string for attributes
	for which no translation is available while using the local		for which no translation is available while using the local
	representation for those cases in which a translation is		representation for those cases in which a translation is
	available.		available.
	</t>		</t>
	<t>		<t>
	Servers that do not provide support for all possible values of		Servers that do not provide support for all possible values of
	the owner and owner_group attributes SHOULD return an error		the owner and owner_group attributes <bcp14>SHOULD</bcp14> return an error
	(NFS4ERR_BADOWNER) when a string is presented that has no		(NFS4ERR_BADOWNER) when a string is presented that has no
	translation, as the value to be set for a SETATTR of the		translation, as the value to be set for a SETATTR of the
	owner, owner_group, or acl attributes. When a server does		owner, owner_group, or acl attributes. When a server does
	accept an owner or owner_group value as valid on a SETATTR		accept an owner or owner_group value as valid on a SETATTR
	(and similarly for the owner and group strings in an acl), it		(and similarly for the owner and group strings in an acl), it
	is promising to return that same string when a corresponding		is promising to return that same string when a corresponding
	GETATTR is done. Configuration changes (including		GETATTR is done. Configuration changes (including
	changes from the mapping of the string to the local representation)		changes from the mapping of the string to the local representation)
	and ill-constructed		and ill-constructed
	name translations (those that contain aliasing) may make that		name translations (those that contain aliasing) may make that
	promise impossible to honor. Servers should make appropriate		promise impossible to honor. Servers should make appropriate
	efforts to avoid a situation in which these attributes have		efforts to avoid a situation in which these attributes have
	their values changed when no real change to ownership has		their values changed when no real change to ownership has
	occurred.		occurred.
	</t>		</t>
	<t>		<t>
	The "dns_domain" portion of the owner string is meant to be a		The "dns_domain" portion of the owner string is meant to be a
	DNS domain name, for example, user@example.org. Servers should		DNS domain name, for example, user@example.org. Servers should
	accept as valid a set of users for at least one domain. A		accept as valid a set of users for at least one domain. A
	server may treat other domains as having no valid		server may treat other domains as having no valid
	translations. A more general service is provided when a		translations. A more general service is provided when a
	server is capable of accepting users for multiple domains, or		server is capable of accepting users for multiple domains, or
	for all domains, subject to security constraints.		for all domains, subject to security constraints.
	</t>		</t>
	<t>		<t>
	In the case where there is no translation available to the		In the case where there is no translation available to the
	client or server, the attribute value will be constructed		client or server, the attribute value will be constructed
	without the "@". Therefore, the absence of the @ from the		without the "@". Therefore, the absence of the @ from the
	owner or owner_group attribute signifies that no translation		owner or owner_group attribute signifies that no translation
	was available at the sender and that the receiver of the		was available at the sender and that the receiver of the
	attribute should not use that string as a basis for		attribute should not use that string as a basis for
	translation into its own internal format. Even though the		translation into its own internal format. Even though the
	attribute value cannot be translated, it may still be useful.		attribute value cannot be translated, it may still be useful.
	In the case of a client, the attribute string may be used for		In the case of a client, the attribute string may be used for
	local display of ownership.		local display of ownership.
	</t>		</t>
	<t>		<t>
	To provide a greater degree of compatibility with NFSv3,		To provide a greater degree of compatibility with NFSv3,
	which identified users and groups by 32-bit unsigned user		which identified users and groups by 32-bit unsigned user
	identifiers and group identifiers, owner and group strings that		identifiers and group identifiers, owner and group strings that
	consist of decimal numeric values with no leading zeros can be		consist of decimal numeric values with no leading zeros can be
	given a special interpretation by clients and servers that		given a special interpretation by clients and servers that
	choose to provide such support. The receiver may treat such a		choose to provide such support. The receiver may treat such a
	user or group string as representing the same user as would be		user or group string as representing the same user as would be
	represented by an NFSv3 uid or gid having the corresponding		represented by an NFSv3 uid or gid having the corresponding
	numeric value. A server is not obligated to accept such a		numeric value. A server is not obligated to accept such a
	string, but may return an NFS4ERR_BADOWNER instead. To avoid		string, but may return an NFS4ERR_BADOWNER instead. To avoid
	this mechanism being used to subvert user and group translation,		this mechanism being used to subvert user and group translation,
	so that a client might pass all of the owners and groups in		so that a client might pass all of the owners and groups in
	numeric form, a server SHOULD return an NFS4ERR_BADOWNER error		numeric form, a server <bcp14>SHOULD</bcp14> return an NFS4ERR_BADOWNER er ror
	when there is a valid translation for the user or owner		when there is a valid translation for the user or owner
	designated in this way. In that case, the client must use the		designated in this way. In that case, the client must use the
	appropriate name@domain string and not the special form for compatibility.		appropriate name@domain string and not the special form for compatibility.
	</t>		</t>
	<t>		<t>
	The owner string "nobody" may be used to designate an		The owner string "nobody" may be used to designate an
	anonymous user, which will be associated with a file created		anonymous user, which will be associated with a file created
	by a security principal that cannot be mapped through normal		by a security principal that cannot be mapped through normal
	means to the owner attribute. Users and implementations		means to the owner attribute. Users and implementations
	of NFSv4.1 SHOULD NOT use "nobody" to designate a real user whose access i		of NFSv4.1 <bcp14>SHOULD NOT</bcp14> use "nobody" to designate a real user
	s not anonymous.		whose access is not anonymous.
	</t>		</t>
	</section>		</section>
			<section anchor="character_case_attributes" numbered="true" toc="default">
	<section anchor="character_case_attributes"		<name>Character Case Attributes</name>
	title="Character Case Attributes">		<t>
	<t>
	With respect to the case_insensitive and case_preserving		With respect to the case_insensitive and case_preserving
	attributes, each UCS-4 character (which UTF-8 encodes) can be		attributes, each UCS-4 character (which UTF-8 encodes) can be
	mapped according to Appendix B.2 of		mapped according to Appendix
	<xref target="RFC3454">RFC 3454</xref>.		<xref target="RFC3454" sectionFormat="bare" section="B.2"/>
			of RFC 3454 <xref target="RFC3454" format="default"/>.
	For general character handling and internationalization issues,		For general character handling and internationalization issues,
	see <xref target="internationalization"/>.		see <xref target="internationalization" format="default"/>.
	</t>		</t>
	</section>		</section>
			<section anchor="dir_not_attrs" numbered="true" toc="default">
	<section title="Directory Notification Attributes" anchor="dir_not_attrs">		<name>Directory Notification Attributes</name>
	<t>		<t>
	As described in <xref target="OP_GET_DIR_DELEGATION" />, the		As described in <xref target="OP_GET_DIR_DELEGATION" format="default"/>, t
			he
	client can request a minimum delay for notifications of changes		client can request a minimum delay for notifications of changes
	to attributes, but the server is free to ignore what the client		to attributes, but the server is free to ignore what the client
	requests. The client can determine in advance what notification		requests. The client can determine in advance what notification
	delays the server will accept by sending a GETATTR operation for either or		delays the server will accept by sending a GETATTR operation for either or
	both of two directory notification attributes. When the client		both of two directory notification attributes. When the client
	calls the GET_DIR_DELEGATION operation and asks for attribute		calls the GET_DIR_DELEGATION operation and asks for attribute
	change notifications, it should request notification delays that		change notifications, it should request notification delays that
	are no less than the values in the server-provided attributes.		are no less than the values in the server-provided attributes.
	</t>		</t>
	<section toc="exclude" anchor="attrdef_dir_notif_delay"		<section toc="exclude" anchor="attrdef_dir_notif_delay" numbered="true">
	title="Attribute 56: dir_notif_delay">		<name>Attribute 56: dir_notif_delay</name>
	<t>		<t>
	The dir_notif_delay attribute is the minimum number of seconds		The dir_notif_delay attribute is the minimum number of seconds
	the server will delay before notifying the client of a change		the server will delay before notifying the client of a change
	to the directory's attributes.		to the directory's attributes.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_dirent_notif_delay" numbered="tru
	<section toc="exclude" anchor="attrdef_dirent_notif_delay"		e">
	title="Attribute 57: dirent_notif_delay">		<name>Attribute 57: dirent_notif_delay</name>
	<t>		<t>
	The dirent_notif_delay attribute is the minimum number of seconds		The dirent_notif_delay attribute is the minimum number of seconds
	the server will delay before notifying the client of a change		the server will delay before notifying the client of a change
	to a file object that has an entry in the directory.		to a file object that has an entry in the directory.
	</t>		</t>
	</section>		</section>
			</section>
	</section>		<section anchor="pnfs_attr_full" numbered="true" toc="default">
			<name>pNFS Attribute Definitions</name>
	<section anchor="pnfs_attr_full" title="pNFS Attribute Definitions">		<section toc="exclude" anchor="attrdef_fs_layout_type" numbered="true">
			<name>Attribute 62: fs_layout_type</name>
	<section toc="exclude" anchor="attrdef_fs_layout_type"		<t>
	title="Attribute 62: fs_layout_type">
	<t>
	The fs_layout_type attribute (see		The fs_layout_type attribute (see
	<xref target="layouttype4"/>) applies to a		<xref target="layouttype4" format="default"/>) applies to a
	file system and indicates what layout types are supported by		file system and indicates what layout types are supported by
	the file system. When the client encounters a new fsid, the		the file system. When the client encounters a new fsid, the
	client SHOULD obtain the value for the fs_layout_type		client <bcp14>SHOULD</bcp14> obtain the value for the fs_layout_type
	attribute associated with the new file system. This attribute		attribute associated with the new file system. This attribute
	is used by the client to determine if the layout types		is used by the client to determine if the layout types
	supported by the server match any of the client's supported		supported by the server match any of the client's supported
	layout types.		layout types.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_layout_alignment" numbered="true"
	<section toc="exclude" anchor="attrdef_layout_alignment"		>
	title="Attribute 66: layout_alignment">		<name>Attribute 66: layout_alignment</name>
	<t>		<t>
	When a client holds layouts on files of a file system, the		When a client holds layouts on files of a file system, the
	layout_alignment attribute indicates the preferred alignment		layout_alignment attribute indicates the preferred alignment
	for I/O to files on that file system. Where possible, the		for I/O to files on that file system. Where possible, the
	client should send READ and WRITE operations with offsets		client should send READ and WRITE operations with offsets
	that are whole multiples of the layout_alignment attribute.		that are whole multiples of the layout_alignment attribute.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_layout_blksize" numbered="true">
	<section toc="exclude" anchor="attrdef_layout_blksize"		<name>Attribute 65: layout_blksize</name>
	title="Attribute 65: layout_blksize">		<t>
	<t>
	When a client holds layouts on files of a file system, the		When a client holds layouts on files of a file system, the
	layout_blksize attribute indicates the preferred block size		layout_blksize attribute indicates the preferred block size
	for I/O to files on that file system. Where possible, the		for I/O to files on that file system. Where possible, the
	client should send READ operations with a count argument that		client should send READ operations with a count argument that
	is a whole multiple of layout_blksize, and WRITE operations		is a whole multiple of layout_blksize, and WRITE operations
	with a data argument of size that is a whole multiple of		with a data argument of size that is a whole multiple of
	layout_blksize.		layout_blksize.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_layout_hint" numbered="true">
	<section toc="exclude" anchor="attrdef_layout_hint"		<name>Attribute 63: layout_hint</name>
	title="Attribute 63: layout_hint">		<t>
	<t>
	The layout_hint attribute (see		The layout_hint attribute (see
	<xref target="layouthint4"/>) may be set on		<xref target="layouthint4" format="default"/>) may be set on
	newly created files to influence the metadata server's choice		newly created files to influence the metadata server's choice
	for the file's layout. If possible, this attribute is one of		for the file's layout. If possible, this attribute is one of
	those set in the initial attributes within the OPEN operation.		those set in the initial attributes within the OPEN operation.
	The metadata server may choose to ignore this attribute. The		The metadata server may choose to ignore this attribute. The
	layout_hint attribute is a subset of the layout structure		layout_hint attribute is a subset of the layout structure
	returned by LAYOUTGET. For example, instead of specifying		returned by LAYOUTGET. For example, instead of specifying
	particular devices, this would be used to suggest the stripe		particular devices, this would be used to suggest the stripe
	width of a file. The server implementation determines which		width of a file. The server implementation determines which
	fields within the layout will be used.		fields within the layout will be used.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_layout_type" numbered="true">
	<section toc="exclude" anchor="attrdef_layout_type"		<name>Attribute 64: layout_type</name>
	title="Attribute 64: layout_type">		<t>
	<t>
	This attribute lists the layout type(s) available for a file.		This attribute lists the layout type(s) available for a file.
	The value returned by the server is for informational purposes		The value returned by the server is for informational purposes
	only. The client will use the LAYOUTGET operation to obtain		only. The client will use the LAYOUTGET operation to obtain
	the information needed in order to perform I/O, for example,		the information needed in order to perform I/O, for example,
	the specific device information for the file and its layout.		the specific device information for the file and its layout.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_mdsthreshold" numbered="true">
	<section toc="exclude" anchor="attrdef_mdsthreshold"		<name>Attribute 68: mdsthreshold</name>
	title="Attribute 68: mdsthreshold">		<t>
	<t>
	This attribute is a server-provided hint used to communicate		This attribute is a server-provided hint used to communicate
	to the client when it is more efficient to send READ and		to the client when it is more efficient to send READ and
	WRITE operations to the metadata server or the data server.		WRITE operations to the metadata server or the data server.
	The two types of thresholds described are file size thresholds		The two types of thresholds described are file size thresholds
	and I/O size thresholds. If a file's size is smaller than the		and I/O size thresholds. If a file's size is smaller than the
	file size threshold, data accesses SHOULD be sent to the		file size threshold, data accesses <bcp14>SHOULD</bcp14> be sent to the
	metadata server. If an I/O request has a length		metadata server. If an I/O request has a length
	that is below the I/O size threshold,		that is below the I/O size threshold,
	the I/O SHOULD be sent to the metadata server.		the I/O <bcp14>SHOULD</bcp14> be sent to the metadata server.
	Each threshold type is specified separately for read and		Each threshold type is specified separately for read and
	write.		write.
	</t>		</t>
	<t>		<t>
	The server MAY provide both types of thresholds for a file.		The server <bcp14>MAY</bcp14> provide both types of thresholds for a file
	If both file size and I/O size are provided, the client SHOULD		.
			If both file size and I/O size are provided, the client <bcp14>SHOULD</bc
			p14>
	reach or exceed both thresholds before sending its read or write		reach or exceed both thresholds before sending its read or write
	requests to the data server. Alternatively, if only one of		requests to the data server. Alternatively, if only one of
	the specified thresholds is reached or exceeded, the I/O requests are		the specified thresholds is reached or exceeded, the I/O requests are
	sent to the metadata server.		sent to the metadata server.
	</t>		</t>
	<t>		<t>
	For each threshold type, a value of zero indicates no READ or WRITE		For each threshold type, a value of zero indicates no READ or WRITE
	should be sent to the metadata server, while a value of all ones		should be sent to the metadata server, while a value of all ones
	indicates that all READs or WRITEs should be sent to the metadata		indicates that all READs or WRITEs should be sent to the metadata
	server.		server.
	</t>		</t>
	<t>		<t>
	The attribute is available on a per-filehandle basis. If the		The attribute is available on a per-filehandle basis. If the
	current filehandle refers to a non-pNFS file or directory, the		current filehandle refers to a non-pNFS file or directory, the
	metadata server should return an attribute that is		metadata server should return an attribute that is
	representative of the filehandle's file system. It is suggested		representative of the filehandle's file system. It is suggested
	that this attribute is queried as part of the OPEN operation.		that this attribute is queried as part of the OPEN operation.
	Due to dynamic system changes, the client should not assume that		Due to dynamic system changes, the client should not assume that
	the attribute will remain constant for any specific time period;		the attribute will remain constant for any specific time period;
	thus, it should be periodically refreshed.		thus, it should be periodically refreshed.
	</t>		</t>
	</section>		</section>
	</section> <!-- "PNFS Attributes" -->		</section>
	<section anchor="retention" title="Retention Attributes">		<section anchor="retention" numbered="true" toc="default">
	<t>		<name>Retention Attributes</name>
			<t>
	Retention is a concept whereby a file object can be placed in an		Retention is a concept whereby a file object can be placed in an
	immutable, undeletable, unrenamable state for a fixed or		immutable, undeletable, unrenamable state for a fixed or
	infinite duration of time. Once in this "retained" state, the		infinite duration of time. Once in this "retained" state, the
	file cannot be moved out of the state until the duration of		file cannot be moved out of the state until the duration of
	retention has been reached.		retention has been reached.
	</t>		</t>
	<t>		<t>
	When retention is enabled, retention MUST extend to the data of		When retention is enabled, retention <bcp14>MUST</bcp14> extend to the dat
	the file, and the name of file. The server MAY extend retention		a of
			the file, and the name of file. The server <bcp14>MAY</bcp14> extend reten
			tion
	to any other property of the file, including any subset of		to any other property of the file, including any subset of
	REQUIRED, RECOMMENDED, and named attributes, with the		<bcp14>REQUIRED</bcp14>, <bcp14>RECOMMENDED</bcp14>, and named attributes, with the
	exceptions noted in this section.		exceptions noted in this section.
	</t>		</t>
	<t>		<t>
	Servers MAY support or not support retention on		Servers <bcp14>MAY</bcp14> support or not support retention on
	any file object type.		any file object type.
	</t>		</t>
	<t>		<t>
	The five retention attributes are explained in the next subsections.		The five retention attributes are explained in the next subsections.
	</t>		</t>
			<section toc="exclude" anchor="attrdef_retention_get" numbered="true">
	<section toc="exclude" anchor="attrdef_retention_get"		<name>Attribute 69: retention_get</name>
	title="Attribute 69: retention_get">		<t>
	<t>
	If retention is enabled for the associated file,		If retention is enabled for the associated file,
	this attribute's value represents the retention		this attribute's value represents the retention
	begin time of the file object. This attribute's		begin time of the file object. This attribute's
	value is only readable with the GETATTR operation		value is only readable with the GETATTR operation
	and MUST NOT be modified by the SETATTR operation		and <bcp14>MUST NOT</bcp14> be modified by the SETATTR operation
	(<xref target="rw_attr"/>). The value of the		(<xref target="rw_attr" format="default"/>). The value of the
	attribute consists of:		attribute consists of:
	<figure>		</t>
	<artwork>		<sourcecode type="xdr"><![CDATA[
	const RET4_DURATION_INFINITE = 0xffffffffffffffff;		const RET4_DURATION_INFINITE = 0xffffffffffffffff;
	struct retention_get4 {		struct retention_get4 {
	uint64_t rg_duration;		uint64_t rg_duration;
	nfstime4 rg_begin_time&lt;1>;		nfstime4 rg_begin_time<1>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	The field rg_duration is the duration in seconds indicating how		The field rg_duration is the duration in seconds indicating how
	long the file will be retained once retention is enabled. The		long the file will be retained once retention is enabled. The
	field rg_begin_time is an array of up to one absolute time		field rg_begin_time is an array of up to one absolute time
	value. If the array is zero length, no beginning retention time		value. If the array is zero length, no beginning retention time
	has been established, and retention is not enabled.		has been established, and retention is not enabled.
	If rg_duration is equal to RET4_DURATION_INFINITE, the file, once		If rg_duration is equal to RET4_DURATION_INFINITE, the file, once
	retention is enabled, will be retained for an infinite duration.		retention is enabled, will be retained for an infinite duration.
	</t>		</t>
	<t>		<t>
	If (as soon as) rg_duration is zero, then rg_begin_time will be		If (as soon as) rg_duration is zero, then rg_begin_time will be
	of zero length, and again, retention is not (no longer) enabled.		of zero length, and again, retention is not (no longer) enabled.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_retention_set" numbered="true">
	<section toc="exclude" anchor="attrdef_retention_set"		<name>Attribute 70: retention_set</name>
	title="Attribute 70: retention_set">		<t>
	<t>
	This attribute is used to set the retention		This attribute is used to set the retention
	duration and optionally enable retention for		duration and optionally enable retention for
	the associated file object. This attribute is		the associated file object. This attribute is
	only modifiable via the SETATTR operation and		only modifiable via the SETATTR operation and
	MUST NOT be retrieved by the GETATTR operation		<bcp14>MUST NOT</bcp14> be retrieved by the GETATTR operation
	(<xref target="rw_attr"/>).		(<xref target="rw_attr" format="default"/>).
	This attribute corresponds to retention_get.		This attribute corresponds to retention_get.
	The value of the attribute consists of:		The value of the attribute consists of:
	<figure>		</t>
	<artwork>		<sourcecode type="xdr"><![CDATA[
	struct retention_set4 {		struct retention_set4 {
	bool rs_enable;		bool rs_enable;
	uint64_t rs_duration&lt;1>;		uint64_t rs_duration<1>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	If the client sets rs_enable to TRUE, then it is enabling		If the client sets rs_enable to TRUE, then it is enabling
	retention on the file object with the begin time of retention		retention on the file object with the begin time of retention
	starting from the server's current time and date. The		starting from the server's current time and date. The
	duration of the retention can also be provided if the		duration of the retention can also be provided if the
	rs_duration array is of length one. The duration is the time in		rs_duration array is of length one. The duration is the time in
	seconds from the begin time of retention, and if set to		seconds from the begin time of retention, and if set to
	RET4_DURATION_INFINITE, the file is to be retained forever. If		RET4_DURATION_INFINITE, the file is to be retained forever. If
	retention is enabled, with no duration specified in either		retention is enabled, with no duration specified in either
	this SETATTR or a previous SETATTR, the duration defaults to		this SETATTR or a previous SETATTR, the duration defaults to
	zero seconds. The server MAY restrict the enabling of		zero seconds. The server <bcp14>MAY</bcp14> restrict the enabling of
	retention or the duration of retention on the basis of the		retention or the duration of retention on the basis of the
	ACE4_WRITE_RETENTION ACL permission. The enabling of		ACE4_WRITE_RETENTION ACL permission. The enabling of
	retention MUST NOT prevent the enabling of event-based		retention <bcp14>MUST NOT</bcp14> prevent the enabling of event-based
	retention or the modification of the retention_hold		retention or the modification of the retention_hold
	attribute.		attribute.
	</t>		</t>
	<t>		<t>
	The following rules apply to both the retention_set and		The following rules apply to both the retention_set and
	retentevt_set attributes.		retentevt_set attributes.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	As long as retention is not enabled, the client		As long as retention is not enabled, the client
	is permitted to decrease the duration.		is permitted to decrease the duration.
	</t>		</li>
	<t>		<li>
	The duration can always be set to an		The duration can always be set to an
	equal or higher value, even if retention is		equal or higher value, even if retention is
	enabled. Note that once retention is enabled,		enabled. Note that once retention is enabled,
	the actual duration (as returned by the		the actual duration (as returned by the
	retention_get or retentevt_get attributes;		retention_get or retentevt_get attributes;
	see <xref target="attrdef_retention_get"/>		see <xref target="attrdef_retention_get" format="default"/>
	or <xref target="attrdef_retentevt_get"/>)		or <xref target="attrdef_retentevt_get" format="default"/>)
	is constantly counting down to zero (one unit		is constantly counting down to zero (one unit
	per second), unless the duration was set to		per second), unless the duration was set to
	RET4_DURATION_INFINITE. Thus, it will not be		RET4_DURATION_INFINITE. Thus, it will not be
	possible for the client to precisely extend the		possible for the client to precisely extend the
	duration on a file that has retention enabled.		duration on a file that has retention enabled.
	</t>		</li>
	<t>		<li>
	While retention is enabled, attempts to disable		While retention is enabled, attempts to disable
	retention or decrease the retention's duration		retention or decrease the retention's duration
	MUST fail with the error NFS4ERR_INVAL.		<bcp14>MUST</bcp14> fail with the error NFS4ERR_INVAL.
	</t>
	<t>		</li>
			<li>
	If the principal attempting to change		If the principal attempting to change
	retention_set or retentevt_set does not have		retention_set or retentevt_set does not have
	ACE4_WRITE_RETENTION permissions, the attempt		ACE4_WRITE_RETENTION permissions, the attempt
	MUST fail with NFS4ERR_ACCESS.		<bcp14>MUST</bcp14> fail with NFS4ERR_ACCESS.
	</t>
	</list>
	</t>
	</section>
	<section toc="exclude" anchor="attrdef_retentevt_get"		</li>
	title="Attribute 71: retentevt_get">		</ul>
	<t>		</section>
			<section toc="exclude" anchor="attrdef_retentevt_get" numbered="true">
			<name>Attribute 71: retentevt_get</name>
			<t>
	Gets the event-based retention duration, and if enabled, the		Gets the event-based retention duration, and if enabled, the
	event-based retention begin time of the file object. This		event-based retention begin time of the file object. This
	attribute is like retention_get, but refers to event-based		attribute is like retention_get, but refers to event-based
	retention. The event that triggers event-based retention is		retention. The event that triggers event-based retention is
	not defined by the NFSv4.1 specification.		not defined by the NFSv4.1 specification.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_retentevt_set" numbered="true">
	<section toc="exclude" anchor="attrdef_retentevt_set"		<name>Attribute 72: retentevt_set</name>
	title="Attribute 72: retentevt_set">		<t>
	<t>
	Sets the event-based retention duration, and optionally enables		Sets the event-based retention duration, and optionally enables
	event-based retention on the file object. This attribute		event-based retention on the file object. This attribute
	corresponds to retentevt_get and is like retention_set, but		corresponds to retentevt_get and is like retention_set, but
	refers to event-based retention. When event-based retention		refers to event-based retention. When event-based retention
	is set, the file MUST be retained even if non-event-based		is set, the file <bcp14>MUST</bcp14> be retained even if non-event-based
	retention has been set, and the duration of non-event-based		retention has been set, and the duration of non-event-based
	retention has been reached. Conversely, when non-event-based		retention has been reached. Conversely, when non-event-based
	retention has been set, the file MUST be retained even if		retention has been set, the file <bcp14>MUST</bcp14> be retained even if
	event-based retention has been set, and the duration of		event-based retention has been set, and the duration of
	event-based retention has been reached. The server MAY		event-based retention has been reached. The server <bcp14>MAY</bcp14>
	restrict the enabling of event-based retention or the duration		restrict the enabling of event-based retention or the duration
	of event-based retention on the basis of the		of event-based retention on the basis of the
	ACE4_WRITE_RETENTION ACL permission. The enabling of		ACE4_WRITE_RETENTION ACL permission. The enabling of
	event-based retention MUST NOT prevent the enabling of		event-based retention <bcp14>MUST NOT</bcp14> prevent the enabling of
	non-event-based retention or the modification of the		non-event-based retention or the modification of the
	retention_hold attribute.		retention_hold attribute.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="attrdef_retention_hold" numbered="true">
	<section toc="exclude" anchor="attrdef_retention_hold"		<name>Attribute 73: retention_hold</name>
	title="Attribute 73: retention_hold">		<t>
	<t>
	Gets or sets administrative retention holds, one hold per bit		Gets or sets administrative retention holds, one hold per bit
	position.		position.
	</t>		</t>
	<t>		<t>
	This attribute allows one to 64 administrative holds, one hold		This attribute allows one to 64 administrative holds, one hold
	per bit on the attribute. If retention_hold is not zero, then		per bit on the attribute. If retention_hold is not zero, then
	the file MUST NOT be deleted, renamed, or modified, even if		the file <bcp14>MUST NOT</bcp14> be deleted, renamed, or modified, even i f
	the duration on enabled event or non-event-based retention has		the duration on enabled event or non-event-based retention has
	been reached. The server MAY restrict the modification of		been reached. The server <bcp14>MAY</bcp14> restrict the modification of
	retention_hold on the basis of the ACE4_WRITE_RETENTION_HOLD		retention_hold on the basis of the ACE4_WRITE_RETENTION_HOLD
	ACL permission. The enabling of administration retention		ACL permission. The enabling of administration retention
	holds does not prevent the enabling of event-based or		holds does not prevent the enabling of event-based or
	non-event-based retention.		non-event-based retention.
	</t>		</t>
	<t>		<t>
	If the principal attempting to change retention_hold does		If the principal attempting to change retention_hold does
	not have ACE4_WRITE_RETENTION_HOLD permissions,		not have ACE4_WRITE_RETENTION_HOLD permissions,
	the attempt MUST fail with NFS4ERR_ACCESS.		the attempt <bcp14>MUST</bcp14> fail with NFS4ERR_ACCESS.
	</t>		</t>
			</section>
			</section>
	</section>		</section>
	</section>		<section anchor="acl" numbered="true" toc="default">
	</section>		<name>Access Control Attributes</name>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<t>
	$ -->
	<!-- Copyright (C) The IETF Trust (2007-2008) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section title="Access Control Attributes" anchor="acl">
	<t>
	Access Control Lists (ACLs) are file attributes that specify		Access Control Lists (ACLs) are file attributes that specify
	fine-grained access control. This section covers the		fine-grained access control. This section covers the
	&quot;acl&quot;, &quot;dacl&quot;, &quot;sacl&quot;,		"acl", "dacl", "sacl",
	&quot;aclsupport&quot;, &quot;mode&quot;, and		"aclsupport", "mode", and
	&quot;mode_set_masked&quot; file attributes and their		"mode_set_masked" file attributes and their
	interactions. Note that file attributes may apply to any file		interactions. Note that file attributes may apply to any file
	system object.		system object.
	</t>		</t>
			<section numbered="true" toc="default">
	<section title="Goals">		<name>Goals</name>
	<t>		<t>
	ACLs and modes represent two well-established models for		ACLs and modes represent two well-established models for
	specifying permissions. This section specifies requirements		specifying permissions. This section specifies requirements
	that attempt to meet the following goals:		that attempt to meet the following goals:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	If a server supports the mode attribute, it should provide		If a server supports the mode attribute, it should provide
	reasonable semantics to clients that only set and retrieve		reasonable semantics to clients that only set and retrieve
	the mode attribute.		the mode attribute.
	</t>		</li>
	<t>		<li>
	If a server supports ACL attributes, it should provide		If a server supports ACL attributes, it should provide
	reasonable semantics to clients that only set and retrieve		reasonable semantics to clients that only set and retrieve
	those attributes.		those attributes.
	</t>		</li>
	<t>		<li>
	On servers that support the mode attribute, if ACL		On servers that support the mode attribute, if ACL
	attributes have never been set on an object, via		attributes have never been set on an object, via
	inheritance or explicitly, the behavior should be		inheritance or explicitly, the behavior should be
	traditional UNIX-like behavior.		traditional UNIX-like behavior.
	</t>		</li>
	<t>		<li>
			<t>
	On servers that support the mode attribute, if the ACL		On servers that support the mode attribute, if the ACL
	attributes have been previously set on an object, either		attributes have been previously set on an object, either
	explicitly or via inheritance:		explicitly or via inheritance:
	<list>		</t>
	<t>		<ul spacing="normal">
			<li>
	Setting only the mode attribute should effectively		Setting only the mode attribute should effectively
	control the traditional UNIX-like permissions of read,		control the traditional UNIX-like permissions of read,
	write, and execute on owner, owner_group, and other.		write, and execute on owner, owner_group, and other.
	</t>		</li>
	<t>		<li>
	Setting only the mode attribute should provide		Setting only the mode attribute should provide
	reasonable security. For example, setting a mode of		reasonable security. For example, setting a mode of
	000 should be enough to ensure that future OPEN operations for		000 should be enough to ensure that future OPEN operations for
	OPEN4_SHARE_ACCESS_READ or OPEN4_SHARE_ACCESS_WRITE by any princ ipal fail, regardless of a		OPEN4_SHARE_ACCESS_READ or OPEN4_SHARE_ACCESS_WRITE by any princ ipal fail, regardless of a
	previously existing or inherited ACL.		previously existing or inherited ACL.
	</t>		</li>
	</list>		</ul>
	</t>		</li>
	<t>		<li>
	NFSv4.1 may introduce different		NFSv4.1 may introduce different
	semantics relating to the mode and ACL attributes,		semantics relating to the mode and ACL attributes,
	but it does not render invalid any previously		but it does not render invalid any previously
	existing implementations. Additionally, this		existing implementations. Additionally, this
	section provides clarifications based on previous		section provides clarifications based on previous
	implementations and discussions around them.		implementations and discussions around them.
	</t>		</li>
	<t>		<li>
	On servers that support both the mode and the acl or		On servers that support both the mode and the acl or
	dacl attributes, the server must keep the two consistent		dacl attributes, the server must keep the two consistent
	with each other. The value of the mode attribute (with		with each other. The value of the mode attribute (with
	the exception of the three high-order bits described in		the exception of the three high-order bits described in
	<xref target="attrdef_mode" />) must be determined entirely		<xref target="attrdef_mode" format="default"/>) must be determined e ntirely
	by the value of the ACL, so that use of the mode is		by the value of the ACL, so that use of the mode is
	never required for anything other than setting the		never required for anything other than setting the
	three high-order bits. See <xref target="setattr" />		three high-order bits. See <xref target="setattr" format="default"/ >
	for exact requirements.		for exact requirements.
	</t>		</li>
	<t>		<li>
	When a mode attribute is set on an object, the ACL		When a mode attribute is set on an object, the ACL
	attributes may need to be modified in order to not conflict		attributes may need to be modified in order to not conflict
	with the new mode. In such cases, it is desirable that the		with the new mode. In such cases, it is desirable that the
	ACL keep as much information as possible. This includes		ACL keep as much information as possible. This includes
	information about inheritance, AUDIT and ALARM ACEs, and		information about inheritance, AUDIT and ALARM ACEs, and
	permissions granted and denied that do not conflict with		permissions granted and denied that do not conflict with
	the new mode.		the new mode.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section numbered="true" toc="default">
			<name>File Attributes Discussion</name>
	<section title="File Attributes Discussion">		<section anchor="attrdef_acl" numbered="true" toc="default">
	<section anchor="attrdef_acl"		<name>Attribute 12: acl</name>
	title="Attribute 12: acl">		<t>
	<t>
	The NFSv4.1 ACL attribute contains an array of Access		The NFSv4.1 ACL attribute contains an array of Access
	Control Entries (ACEs) that are associated with the file		Control Entries (ACEs) that are associated with the file
	system object. Although the client can set and		system object. Although the client can set and
	get the acl attribute, the server is responsible for using		get the acl attribute, the server is responsible for using
	the ACL to perform access control. The client can use the		the ACL to perform access control. The client can use the
	OPEN or ACCESS operations to check access without modifying		OPEN or ACCESS operations to check access without modifying
	or reading data or metadata.		or reading data or metadata.
	</t>		</t>
			<t>
	<t>
	The NFS ACE structure is defined as follows:		The NFS ACE structure is defined as follows:
	</t>		</t>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	typedef uint32_t acetype4;		typedef uint32_t acetype4;
	</artwork>
	</figure>
	<figure>
	<artwork>
	typedef uint32_t aceflag4;		typedef uint32_t aceflag4;
	</artwork>
	</figure>
	<figure>
	<artwork>
	typedef uint32_t acemask4;		typedef uint32_t acemask4;
	</artwork>
	</figure>
	<figure>
	<artwork>
	struct nfsace4 {		struct nfsace4 {
	acetype4 type;		acetype4 type;
	aceflag4 flag;		aceflag4 flag;
	acemask4 access_mask;		acemask4 access_mask;
	utf8str_mixed who;		utf8str_mixed who;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	To determine if a request succeeds, the server processes		To determine if a request succeeds, the server processes
	each nfsace4 entry in order. Only ACEs that have a "who"		each nfsace4 entry in order. Only ACEs that have a "who"
	that matches the requester are considered. Each ACE is		that matches the requester are considered. Each ACE is
	processed until all of the bits of the requester's access		processed until all of the bits of the requester's access
	have been ALLOWED. Once a bit (see below) has been ALLOWED		have been ALLOWED. Once a bit (see below) has been ALLOWED
	by an ACCESS_ALLOWED_ACE, it is no longer considered in the		by an ACCESS_ALLOWED_ACE, it is no longer considered in the
	processing of later ACEs. If an ACCESS_DENIED_ACE is		processing of later ACEs. If an ACCESS_DENIED_ACE is
	encountered where the requester's access still has unALLOWED		encountered where the requester's access still has unALLOWED
	bits in common with the "access_mask" of the ACE, the		bits in common with the "access_mask" of the ACE, the
	request is denied. When the ACL is fully processed, if		request is denied. When the ACL is fully processed, if
	there are bits in the requester's mask that have not been		there are bits in the requester's mask that have not been
	ALLOWED or DENIED, access is denied.		ALLOWED or DENIED, access is denied.
	</t>		</t>
	<t>		<t>
	Unlike the ALLOW and DENY ACE types, the ALARM and AUDIT ACE		Unlike the ALLOW and DENY ACE types, the ALARM and AUDIT ACE
	types do not affect a requester's access, and instead are		types do not affect a requester's access, and instead are
	for triggering events as a result of a requester's access		for triggering events as a result of a requester's access
	attempt. Therefore, AUDIT and ALARM ACEs are processed only		attempt. Therefore, AUDIT and ALARM ACEs are processed only
	after processing ALLOW and DENY ACEs.		after processing ALLOW and DENY ACEs.
	</t>		</t>
	<t>		<t>
	The NFSv4.1 ACL model is quite rich. Some server		The NFSv4.1 ACL model is quite rich. Some server
	platforms may provide access-control functionality that goes		platforms may provide access-control functionality that goes
	beyond the UNIX-style mode attribute, but that is not as		beyond the UNIX-style mode attribute, but that is not as
	rich as the NFS ACL model. So that users can take advantage		rich as the NFS ACL model. So that users can take advantage
	of this more limited functionality, the server may support		of this more limited functionality, the server may support
	the acl attributes by mapping between its ACL model and the		the acl attributes by mapping between its ACL model and the
	NFSv4.1 ACL model. Servers must ensure that the ACL		NFSv4.1 ACL model. Servers must ensure that the ACL
	they actually store or enforce is at least as strict as the		they actually store or enforce is at least as strict as the
	NFSv4 ACL that was set. It is tempting to accomplish this		NFSv4 ACL that was set. It is tempting to accomplish this
	by rejecting any ACL that falls outside the small set that		by rejecting any ACL that falls outside the small set that
	skipping to change at line 8503 ¶		skipping to change at line 8754 ¶
	of having a common NFSv4 ACL protocol. Therefore, servers		of having a common NFSv4 ACL protocol. Therefore, servers
	should accept every ACL that they can without compromising		should accept every ACL that they can without compromising
	security. To help accomplish this, servers may make a		security. To help accomplish this, servers may make a
	special exception, in the case of unsupported permission		special exception, in the case of unsupported permission
	bits, to the rule that bits not ALLOWED or DENIED by an ACL		bits, to the rule that bits not ALLOWED or DENIED by an ACL
	must be denied. For example, a UNIX-style server might		must be denied. For example, a UNIX-style server might
	choose to silently allow read attribute permissions even		choose to silently allow read attribute permissions even
	though an ACL does not explicitly allow those permissions.		though an ACL does not explicitly allow those permissions.
	(An ACL that explicitly denies permission to read attributes		(An ACL that explicitly denies permission to read attributes
	should still be rejected.)		should still be rejected.)
	</t>		</t>
	<t>		<t>
	The situation is complicated by the fact that a server may		The situation is complicated by the fact that a server may
	have multiple modules that enforce ACLs. For example, the		have multiple modules that enforce ACLs. For example, the
	enforcement for NFSv4.1 access may be different from,		enforcement for NFSv4.1 access may be different from,
	but not weaker than, the enforcement for local access, and		but not weaker than, the enforcement for local access, and
	both may be different from the enforcement for access		both may be different from the enforcement for access
	through other protocols such as SMB (Server Message Block). So it may be useful for		through other protocols such as SMB (Server Message Block). So it may be useful for
	a server to accept an ACL even if not all of its modules are		a server to accept an ACL even if not all of its modules are
	able to support it.		able to support it.
	</t>		</t>
	<t>		<t>
	The guiding principle with regard to NFSv4 access is		The guiding principle with regard to NFSv4 access is
	that the server must not accept ACLs that appear to		that the server must not accept ACLs that appear to
	make access to the file more restrictive than it really is.		make access to the file more restrictive than it really is.
	</t>		</t>
			<section numbered="true" toc="default">
	<section title="ACE Type">		<name>ACE Type</name>
	<t>		<t>
	The constants used for the type field (acetype4) are as		The constants used for the type field (acetype4) are as
	follows:		follows:
	</t>		</t>
			<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	const ACE4_ACCESS_ALLOWED_ACE_TYPE = 0x00000000;		const ACE4_ACCESS_ALLOWED_ACE_TYPE = 0x00000000;
	const ACE4_ACCESS_DENIED_ACE_TYPE = 0x00000001;		const ACE4_ACCESS_DENIED_ACE_TYPE = 0x00000001;
	const ACE4_SYSTEM_AUDIT_ACE_TYPE = 0x00000002;		const ACE4_SYSTEM_AUDIT_ACE_TYPE = 0x00000002;
	const ACE4_SYSTEM_ALARM_ACE_TYPE = 0x00000003;		const ACE4_SYSTEM_ALARM_ACE_TYPE = 0x00000003;
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	Only the ALLOWED and DENIED bits may be used in the		Only the ALLOWED and DENIED bits may be used in the
	dacl attribute, and only the AUDIT and ALARM bits may be		dacl attribute, and only the AUDIT and ALARM bits may be
	used in the sacl attribute. All four are permitted in the		used in the sacl attribute. All four are permitted in the
	acl attribute.		acl attribute.
	</t>		</t>
	<texttable>		<table align="center">
	<ttcol>Value</ttcol>		<thead>
	<ttcol>Abbreviation</ttcol>		<tr>
	<ttcol>Description</ttcol>		<th align="left">Value</th>
	<c>ACE4_ACCESS_ALLOWED_ACE_TYPE</c>		<th align="left">Abbreviation</th>
	<c>ALLOW</c>		<th align="left">Description</th>
	<c>		</tr>
			</thead>
			<tbody>
			<tr>
			<td align="left">ACE4_ACCESS_ALLOWED_ACE_TYPE</td>
			<td align="left">ALLOW</td>
			<td align="left">
	Explicitly grants the access defined in acemask4 to		Explicitly grants the access defined in acemask4 to
	the file or directory.		the file or directory.
	</c>		</td>
	<c>ACE4_ACCESS_DENIED_ACE_TYPE</c>		</tr>
	<c>DENY</c>		<tr>
	<c>		<td align="left">ACE4_ACCESS_DENIED_ACE_TYPE</td>
			<td align="left">DENY</td>
			<td align="left">
	Explicitly denies the access defined in acemask4 to		Explicitly denies the access defined in acemask4 to
	the file or directory.		the file or directory.
	</c>		</td>
	<c>ACE4_SYSTEM_AUDIT_ACE_TYPE</c>		</tr>
	<c>AUDIT</c>		<tr>
	<c>		<td align="left">ACE4_SYSTEM_AUDIT_ACE_TYPE</td>
			<td align="left">AUDIT</td>
			<td align="left">
	Log (in a system-dependent way) any access attempt to		Log (in a system-dependent way) any access attempt to
	a file or directory that uses any of the access		a file or directory that uses any of the access
	methods specified in acemask4.		methods specified in acemask4.
	</c>		</td>
	<c>ACE4_SYSTEM_ALARM_ACE_TYPE</c>		</tr>
	<c>ALARM</c>		<tr>
	<c>		<td align="left">ACE4_SYSTEM_ALARM_ACE_TYPE</td>
			<td align="left">ALARM</td>
			<td align="left">
	Generate an alarm (in a system-dependent way) when any		Generate an alarm (in a system-dependent way) when any
	access attempt is made to a file or directory for the		access attempt is made to a file or directory for the
	access methods specified in acemask4.		access methods specified in acemask4.
	</c>		</td>
	</texttable>		</tr>
			</tbody>
			</table>
	<t>		<t>
	The &quot;Abbreviation&quot; column denotes how the		The "Abbreviation" column denotes how the
	types will be referred to throughout the rest of this		types will be referred to throughout the rest of this
	section.		section.
	</t>		</t>
	</section>		</section>
	<section anchor="attrdef_aclsupport"		<section anchor="attrdef_aclsupport" numbered="true" toc="default">
	title="Attribute 13: aclsupport">		<name>Attribute 13: aclsupport</name>
	<t>		<t>
	A server need not support all of the above ACE types.		A server need not support all of the above ACE types.
	This attribute indicates which ACE types are supported for		This attribute indicates which ACE types are supported for
	the current file system. The bitmask constants used to		the current file system. The bitmask constants used to
	represent the above definitions within the aclsupport		represent the above definitions within the aclsupport
	attribute are as follows:		attribute are as follows:
	</t>		</t>
			<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	const ACL4_SUPPORT_ALLOW_ACL = 0x00000001;		const ACL4_SUPPORT_ALLOW_ACL = 0x00000001;
	const ACL4_SUPPORT_DENY_ACL = 0x00000002;		const ACL4_SUPPORT_DENY_ACL = 0x00000002;
	const ACL4_SUPPORT_AUDIT_ACL = 0x00000004;		const ACL4_SUPPORT_AUDIT_ACL = 0x00000004;
	const ACL4_SUPPORT_ALARM_ACL = 0x00000008;		const ACL4_SUPPORT_ALARM_ACL = 0x00000008;
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	Servers that support either the ALLOW or DENY ACE type		Servers that support either the ALLOW or DENY ACE type
	SHOULD support both ALLOW and DENY ACE types.		<bcp14>SHOULD</bcp14> support both ALLOW and DENY ACE types.
	</t>		</t>
	<t>		<t>
	Clients should not attempt to set an ACE unless the server		Clients should not attempt to set an ACE unless the server
	claims support for that ACE type. If the server receives a		claims support for that ACE type. If the server receives a
	request to set an ACE that it cannot store, it MUST reject		request to set an ACE that it cannot store, it <bcp14>MUST</bcp14> r eject
	the request with NFS4ERR_ATTRNOTSUPP. If the server		the request with NFS4ERR_ATTRNOTSUPP. If the server
	receives a request to set an ACE that it can store but		receives a request to set an ACE that it can store but
	cannot enforce, the server SHOULD reject the request with		cannot enforce, the server <bcp14>SHOULD</bcp14> reject the request with
	NFS4ERR_ATTRNOTSUPP.		NFS4ERR_ATTRNOTSUPP.
	</t>		</t>
	<t>		<t>
	Support for any of the ACL attributes is		Support for any of the ACL attributes is
	optional (albeit RECOMMENDED).		optional (albeit <bcp14>RECOMMENDED</bcp14>).
	However, a server that supports either of the new ACL		However, a server that supports either of the new ACL
	attributes (dacl or sacl) MUST allow use of the new ACL		attributes (dacl or sacl) <bcp14>MUST</bcp14> allow use of the new A CL
	attributes to access all of the ACE types that it		attributes to access all of the ACE types that it
	supports. In other words, if such a server supports ALLOW		supports. In other words, if such a server supports ALLOW
	or DENY ACEs, then it MUST support the dacl attribute, and		or DENY ACEs, then it <bcp14>MUST</bcp14> support the dacl attribute
	if it supports AUDIT or ALARM ACEs, then it MUST support		, and
			if it supports AUDIT or ALARM ACEs, then it <bcp14>MUST</bcp14> supp
			ort
	the sacl attribute.		the sacl attribute.
	</t>		</t>
	</section>		</section>
	<section anchor="acemask" title="ACE Access Mask">		<section anchor="acemask" numbered="true" toc="default">
	<t>		<name>ACE Access Mask</name>
			<t>
	The bitmask constants used for the access mask field		The bitmask constants used for the access mask field
	are as follows:		are as follows:
	</t>		</t>
			<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	const ACE4_READ_DATA = 0x00000001;		const ACE4_READ_DATA = 0x00000001;
	const ACE4_LIST_DIRECTORY = 0x00000001;		const ACE4_LIST_DIRECTORY = 0x00000001;
	const ACE4_WRITE_DATA = 0x00000002;		const ACE4_WRITE_DATA = 0x00000002;
	const ACE4_ADD_FILE = 0x00000002;		const ACE4_ADD_FILE = 0x00000002;
	const ACE4_APPEND_DATA = 0x00000004;		const ACE4_APPEND_DATA = 0x00000004;
	const ACE4_ADD_SUBDIRECTORY = 0x00000004;		const ACE4_ADD_SUBDIRECTORY = 0x00000004;
	const ACE4_READ_NAMED_ATTRS = 0x00000008;		const ACE4_READ_NAMED_ATTRS = 0x00000008;
	const ACE4_WRITE_NAMED_ATTRS = 0x00000010;		const ACE4_WRITE_NAMED_ATTRS = 0x00000010;
	const ACE4_EXECUTE = 0x00000020;		const ACE4_EXECUTE = 0x00000020;
	const ACE4_DELETE_CHILD = 0x00000040;		const ACE4_DELETE_CHILD = 0x00000040;
	const ACE4_READ_ATTRIBUTES = 0x00000080;		const ACE4_READ_ATTRIBUTES = 0x00000080;
	const ACE4_WRITE_ATTRIBUTES = 0x00000100;		const ACE4_WRITE_ATTRIBUTES = 0x00000100;
	const ACE4_WRITE_RETENTION = 0x00000200;		const ACE4_WRITE_RETENTION = 0x00000200;
	const ACE4_WRITE_RETENTION_HOLD = 0x00000400;		const ACE4_WRITE_RETENTION_HOLD = 0x00000400;
	const ACE4_DELETE = 0x00010000;		const ACE4_DELETE = 0x00010000;
	const ACE4_READ_ACL = 0x00020000;		const ACE4_READ_ACL = 0x00020000;
	const ACE4_WRITE_ACL = 0x00040000;		const ACE4_WRITE_ACL = 0x00040000;
	const ACE4_WRITE_OWNER = 0x00080000;		const ACE4_WRITE_OWNER = 0x00080000;
	const ACE4_SYNCHRONIZE = 0x00100000;		const ACE4_SYNCHRONIZE = 0x00100000;
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	Note that some masks have coincident values, for		Note that some masks have coincident values, for
	example, ACE4_READ_DATA and ACE4_LIST_DIRECTORY.		example, ACE4_READ_DATA and ACE4_LIST_DIRECTORY.
	The mask entries ACE4_LIST_DIRECTORY,		The mask entries ACE4_LIST_DIRECTORY,
	ACE4_ADD_FILE, and ACE4_ADD_SUBDIRECTORY are		ACE4_ADD_FILE, and ACE4_ADD_SUBDIRECTORY are
	intended to be used with directory objects,		intended to be used with directory objects,
	while ACE4_READ_DATA, ACE4_WRITE_DATA, and		while ACE4_READ_DATA, ACE4_WRITE_DATA, and
	ACE4_APPEND_DATA are intended to be used with		ACE4_APPEND_DATA are intended to be used with
	non-directory objects.		non-directory objects.
	</t>		</t>
	<section title="Discussion of Mask Attributes">		<section numbered="true" toc="default">
	<t>		<name>Discussion of Mask Attributes</name>
	<list style="hanging">
	<t hangText="ACE4_READ_DATA">		<t>ACE4_READ_DATA</t>
	<list style="hanging">		<ul empty="true"><li> <dl newline="true" spacing="normal">
	<t hangText="Operation(s) affected:">		<dt>Operation(s) affected:</dt>
	<list style="hanging">		<dd><t>READ</t>
	<t hangText="READ" />		<t>OPEN</t></dd>
	<t hangText="OPEN" />		<dt>Discussion:</dt>
	</list>		<dd>
	</t>		<t>
	<t hangText="Discussion:">
	<vspace blankLines='1' />
	Permission to read the data of the file.		Permission to read the data of the file.
	<vspace blankLines='1' />		</t>
	Servers SHOULD allow a user the ability to read the data		<t>
			Servers <bcp14>SHOULD</bcp14> allow a user the ability to r
			ead the data
	of the file when only the ACE4_EXECUTE access mask bit is		of the file when only the ACE4_EXECUTE access mask bit is
	allowed.		allowed.
	</t>		</t>
	</list>		</dd>
	</t>		</dl></li>
			</ul>
	<t hangText="ACE4_LIST_DIRECTORY">		<t>ACE4_LIST_DIRECTORY</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="READDIR" />		<dd>READDIR</dd>
	</list>
	</t>		<dt>Discussion:</dt>
	<t hangText="Discussion:">		<dd>
	<vspace blankLines='1' />
	Permission to list the contents of a directory.		Permission to list the contents of a directory.
	</t>		</dd>
	</list>		</dl>
	</t>		</li>
			</ul>
	<t hangText="ACE4_WRITE_DATA">		<t>ACE4_WRITE_DATA</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="WRITE" />		<dd><t>WRITE</t>
	<t hangText="OPEN" />		<t>OPEN</t>
	<t hangText="SETATTR of size" />		<t>SETATTR of size</t>
	</list>		</dd>
	</t>
	<t hangText="Discussion:">		<dt>Discussion:</dt>
	<vspace blankLines='1' />		<dd>
	Permission to modify a file's data.		Permission to modify a file's data.
	</t>		</dd>
	</list>		</dl>
	</t>		</li></ul>
	<t hangText="ACE4_ADD_FILE">		<t>ACE4_ADD_FILE</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="CREATE" />		<dd><t>CREATE</t>
	<t hangText="LINK" />		<t>LINK</t>
	<t hangText="OPEN" />		<t>OPEN</t>
	<t hangText="RENAME" />		<t>RENAME</t>
	</list>		</dd>
	</t>
	<t hangText="Discussion:">		<dt>Discussion:</dt>
	<vspace blankLines='1' />		<dd>
	Permission to add a new file in a directory.		Permission to add a new file in a directory.
	The CREATE operation is affected when nfs_ftype4		The CREATE operation is affected when nfs_ftype4
	is NF4LNK, NF4BLK, NF4CHR, NF4SOCK, or		is NF4LNK, NF4BLK, NF4CHR, NF4SOCK, or
	NF4FIFO. (NF4DIR is not listed because it is		NF4FIFO. (NF4DIR is not listed because it is
	covered by ACE4_ADD_SUBDIRECTORY.) OPEN is		covered by ACE4_ADD_SUBDIRECTORY.) OPEN is
	affected when used to create a regular file.		affected when used to create a regular file.
	LINK and RENAME are always affected.		LINK and RENAME are always affected.
	</t>		</dd>
	</list>		</dl></li>
	</t>		</ul>
	<t hangText="ACE4_APPEND_DATA">		<t>ACE4_APPEND_DATA</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="WRITE" />		<dd><t>WRITE</t>
	<t hangText="OPEN" />		<t>OPEN</t>
	<t hangText="SETATTR of size" />		<t>SETATTR of size</t>
	</list>		</dd>
	</t>
	<t hangText="Discussion:">		<dt>Discussion:</dt>
	<vspace blankLines='1' />		<dd>
	The ability to modify a file's data, but only		The ability to modify a file's data, but only
	starting at EOF. This allows for the notion of		starting at EOF. This allows for the notion of
	append-only files, by allowing ACE4_APPEND_DATA		append-only files, by allowing ACE4_APPEND_DATA
	and denying ACE4_WRITE_DATA to the same user or		and denying ACE4_WRITE_DATA to the same user or
	group. If a file has an ACL such as the one		group. If a file has an ACL such as the one
	described above and a WRITE request is made for		described above and a WRITE request is made for
	somewhere other than EOF, the server SHOULD		somewhere other than EOF, the server <bcp14>SHOULD</bcp14>
	return NFS4ERR_ACCESS.		return NFS4ERR_ACCESS.
	</t>		</dd>
	</list>		</dl></li>
	</t>		</ul>
	<t hangText="ACE4_ADD_SUBDIRECTORY">		<t>ACE4_ADD_SUBDIRECTORY</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="CREATE" />		<dd><t>CREATE</t>
	<t hangText="RENAME" />		<t>RENAME</t></dd>
	</list>
	</t>		<dt>Discussion:</dt>
	<t hangText="Discussion:">		<dd>
	<vspace blankLines='1' />
	Permission to create a subdirectory in a		Permission to create a subdirectory in a
	directory. The CREATE operation is affected		directory. The CREATE operation is affected
	when nfs_ftype4 is NF4DIR. The RENAME operation		when nfs_ftype4 is NF4DIR. The RENAME operation
	is always affected.		is always affected.
	</t>		</dd>
	</list>		</dl></li>
	</t>		</ul>
	<t hangText="ACE4_READ_NAMED_ATTRS">		<t>ACE4_READ_NAMED_ATTRS</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="OPENATTR" />		<dd><t>OPENATTR</t></dd>
	</list>
	</t>		<dt>Discussion:</dt>
	<t hangText="Discussion:">		<dd>
	<vspace blankLines='1' />
	Permission to read the named attributes of a		Permission to read the named attributes of a
	file or to look up the named attribute		file or to look up the named attribute
	directory. OPENATTR is affected when it is not		directory. OPENATTR is affected when it is not
	used to create a named attribute directory.		used to create a named attribute directory.
	This is when 1) createdir is TRUE, but a named		This is when 1) createdir is TRUE, but a named
	attribute directory already exists, or 2)		attribute directory already exists, or 2)
	createdir is FALSE.		createdir is FALSE.
	</t>		</dd>
	</list>		</dl></li>
	</t>		</ul>
	<t hangText="ACE4_WRITE_NAMED_ATTRS">		<t>ACE4_WRITE_NAMED_ATTRS</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="OPENATTR" />		<dd><t>OPENATTR</t>
	<t hangText="" />		</dd>
	</list>		<dt>Discussion:</dt>
	</t>		<dd>
	<t hangText="Discussion:">
	<vspace blankLines='1' />
	Permission to write the named attributes of a		Permission to write the named attributes of a
	file or to create a named attribute directory.		file or to create a named attribute directory.
	OPENATTR is affected when it is used to create a		OPENATTR is affected when it is used to create a
	named attribute directory. This is when		named attribute directory. This is when
	createdir is TRUE and no named attribute		createdir is TRUE and no named attribute
	directory exists. The ability to check whether		directory exists. The ability to check whether
	or not a named attribute directory exists		or not a named attribute directory exists
	depends on the ability to look it up; therefore,		depends on the ability to look it up; therefore,
	users also need the ACE4_READ_NAMED_ATTRS		users also need the ACE4_READ_NAMED_ATTRS
	permission in order to create a named attribute		permission in order to create a named attribute
	directory.		directory.
	</t>		</dd>
	</list>		</dl>
	</t>		</li>
			</ul>
	<t hangText="ACE4_EXECUTE">		<t>ACE4_EXECUTE</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="READ" />		<dd><t>READ</t>
	<t hangText="OPEN" />		<t>OPEN</t>
	<t hangText="REMOVE" />		<t>REMOVE</t>
	<t hangText="RENAME" />		<t>RENAME</t>
	<t hangText="LINK" />		<t>LINK</t>
	<t hangText="CREATE" />		<t>CREATE</t>
	</list>		</dd>
	</t>
	<t hangText="Discussion:">		<dt>Discussion:</dt>
	<vspace blankLines='1' />		<dd>
			<t>
	Permission to execute a file.		Permission to execute a file.
	<vspace blankLines='1' />		</t>
	Servers SHOULD allow a		<t>
			Servers <bcp14>SHOULD</bcp14> allow a
	user the ability to read the data of the file		user the ability to read the data of the file
	when only the ACE4_EXECUTE access mask bit is		when only the ACE4_EXECUTE access mask bit is
	allowed. This is because there is no way to		allowed. This is because there is no way to
	execute a file without reading the contents.		execute a file without reading the contents.
	Though a server may treat ACE4_EXECUTE and		Though a server may treat ACE4_EXECUTE and
	ACE4_READ_DATA bits identically when deciding to		ACE4_READ_DATA bits identically when deciding to
	permit a READ operation, it SHOULD still allow		permit a READ operation, it <bcp14>SHOULD</bcp14> still all ow
	the two bits to be set independently in ACLs,		the two bits to be set independently in ACLs,
	and MUST distinguish between them when replying		and <bcp14>MUST</bcp14> distinguish between them when reply ing
	to ACCESS operations. In particular, servers		to ACCESS operations. In particular, servers
	SHOULD NOT silently turn on one of the two bits		<bcp14>SHOULD NOT</bcp14> silently turn on one of the two b its
	when the other is set, as that would make it		when the other is set, as that would make it
	impossible for the client to correctly enforce		impossible for the client to correctly enforce
	the distinction between read and execute		the distinction between read and execute
	permissions.		permissions.
	<vspace blankLines='1' />		</t>
	As an example, following a SETATTR of the following ACL:		<t>As an example, following a SETATTR of the following ACL:
	<vspace blankLines='1' />		</t>
	nfsuser:ACE4_EXECUTE:ALLOW		<ul empty="true">
	<vspace blankLines='1' />		<li>nfsuser:ACE4_EXECUTE:ALLOW</li>
	A subsequent GETATTR of ACL for that file SHOULD return:		</ul>
	<vspace blankLines='1' />		<t>
	nfsuser:ACE4_EXECUTE:ALLOW		A subsequent GETATTR of ACL for that file <bcp14>SHOULD</bc
	<vspace blankLines='1' />		p14> return:
			</t>
			<ul empty="true">
			<li>nfsuser:ACE4_EXECUTE:ALLOW</li>
			</ul>
			<t>
	Rather than:		Rather than:
	<vspace blankLines='1' />		</t>
			<ul empty="true">
			<li>
	nfsuser:ACE4_EXECUTE/ACE4_READ_DATA:ALLOW		nfsuser:ACE4_EXECUTE/ACE4_READ_DATA:ALLOW
	</t>		</li></ul>
	</list>		</dd>
	</t>		</dl></li>
			</ul>
	<t hangText="ACE4_EXECUTE">		<t>ACE4_EXECUTE</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="LOOKUP" />		<dd>LOOKUP</dd>
	</list>
	</t>		<dt>Discussion:</dt>
	<t hangText="Discussion:">		<dd>
	<vspace blankLines='1' />
	Permission to traverse/search a directory.		Permission to traverse/search a directory.
	</t>		</dd>
	</list>		</dl>
	</t>		</li></ul>
	<t hangText="ACE4_DELETE_CHILD">		<t>ACE4_DELETE_CHILD</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="REMOVE" />		<dd><t>REMOVE</t>
	<t hangText="RENAME" />		<t>RENAME</t></dd>
	</list>
	</t>		<dt>Discussion:</dt>
	<t hangText="Discussion:">		<dd>
	<vspace blankLines='1' />
	Permission to delete a file or directory within		Permission to delete a file or directory within
	a directory.		a directory.
	See <xref		See <xref target="delete-delete_child" format="default"/>
	target="delete-delete_child"/>
	for information on ACE4_DELETE and		for information on ACE4_DELETE and
	ACE4_DELETE_CHILD interact.		ACE4_DELETE_CHILD interact.
			</dd>
			</dl></li>
			</ul>
	</t>		<t>ACE4_READ_ATTRIBUTES</t>
	</list>		<ul empty="true"><li>
	</t>		<dl newline="true" spacing="normal">
			<dt>Operation(s) affected:</dt>
			<dd><t>GETATTR of file system object attributes</t>
			<t>VERIFY</t>
			<t>NVERIFY</t>
			<t>READDIR</t></dd>
	<t hangText="ACE4_READ_ATTRIBUTES">		<dt>Discussion:</dt>
	<list style="hanging">		<dd>
	<t hangText="Operation(s) affected:">
	<list style="hanging">
	<t hangText="GETATTR of file system object attributes" />
	<t hangText="VERIFY" />
	<t hangText="NVERIFY" />
	<t hangText="READDIR" />
	</list>
	</t>
	<t hangText="Discussion:">
	<vspace blankLines='1' />
	The ability to read basic attributes (non-ACLs)		The ability to read basic attributes (non-ACLs)
	of a file. On a UNIX system, basic attributes		of a file. On a UNIX system, basic attributes
	can be thought of as the stat-level attributes.		can be thought of as the stat-level attributes.
	Allowing this access mask bit would mean that the		Allowing this access mask bit would mean that the
	entity can execute "ls -l" and stat. If a		entity can execute "ls -l" and stat. If a
	READDIR operation requests attributes, this mask		READDIR operation requests attributes, this mask
	must be allowed for the READDIR to succeed.		must be allowed for the READDIR to succeed.
	</t>		</dd>
	</list>		</dl></li>
	</t>		</ul>
	<t hangText="ACE4_WRITE_ATTRIBUTES">		<t>ACE4_WRITE_ATTRIBUTES</t>
	<list style="hanging">
	<t hangText="Operation(s) affected:">		<ul empty="true"><li>
	<list style="hanging">		<dl newline="true" spacing="normal">
	<t hangText="SETATTR of time_access_set, time_backup," />		<dt>Operation(s) affected:</dt>
	<t hangText="time_create, time_modify_set, mimetype, hidd		<dd><t>SETATTR of time_access_set, time_backup,</t>
	en, system" />		<t>time_create, time_modify_set, mimetype, hidden, syste
	</list>		m</t></dd>
	</t>
	<t hangText="Discussion:">		<dt>Discussion:</dt>
	<vspace blankLines='1' />		<dd>
	Permission to change the times associated with a		Permission to change the times associated with a
	file or directory to an arbitrary value. Also		file or directory to an arbitrary value. Also
	permission to change the mimetype, hidden, and		permission to change the mimetype, hidden, and
	system attributes. A user having		system attributes. A user having
	ACE4_WRITE_DATA or ACE4_WRITE_ATTRIBUTES will be		ACE4_WRITE_DATA or ACE4_WRITE_ATTRIBUTES will be
	allowed to set the times associated with a file		allowed to set the times associated with a file
	to the current server time.		to the current server time.
	</t>		</dd>
	</list>		</dl></li>
	</t>		</ul>
	<t hangText="ACE4_WRITE_RETENTION">		<t>ACE4_WRITE_RETENTION</t>
	<list style="hanging">
	<t hangText="Operation(s) affected:">		<ul empty="true"><li>
	<list style="hanging">		<dl newline="true" spacing="normal">
	<t hangText="SETATTR of retention_set, retentevt_set." />		<dt>Operation(s) affected:</dt>
	</list>		<dd>SETATTR of retention_set, retentevt_set.</dd>
	</t>
	<t hangText="Discussion:">		<dt>Discussion:</dt>
	<vspace blankLines='1' />		<dd>
	Permission to modify the durations of event and		Permission to modify the durations of event and
	non-event-based retention. Also permission to		non-event-based retention. Also permission to
	enable event and non-event-based retention. A		enable event and non-event-based retention. A
	server MAY behave such that setting		server <bcp14>MAY</bcp14> behave such that setting
	ACE4_WRITE_ATTRIBUTES allows		ACE4_WRITE_ATTRIBUTES allows
	ACE4_WRITE_RETENTION.		ACE4_WRITE_RETENTION.
	</t>		</dd>
	</list>		</dl></li>
	</t>		</ul>
	<t hangText="ACE4_WRITE_RETENTION_HOLD">		<t>ACE4_WRITE_RETENTION_HOLD</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="SETATTR of retention_hold." />		<dd>SETATTR of retention_hold.</dd>
	</list>		<dt>Discussion:</dt>
	</t>		<dd>
	<t hangText="Discussion:">
	<vspace blankLines='1' />
	Permission to modify the administration		Permission to modify the administration
	retention holds. A server MAY map		retention holds. A server <bcp14>MAY</bcp14> map
	ACE4_WRITE_ATTRIBUTES to		ACE4_WRITE_ATTRIBUTES to
	ACE_WRITE_RETENTION_HOLD.		ACE_WRITE_RETENTION_HOLD.
	</t>		</dd>
	</list>		</dl></li>
	</t>		</ul>
	<t hangText="ACE4_DELETE">
	<list style="hanging">
	<t hangText="Operation(s) affected:">
	<list style="hanging">
	<t hangText="REMOVE" />
	</list>
	</t>
	<t hangText="Discussion:">
	<vspace blankLines='1' />
			<t>ACE4_DELETE</t>
			<ul empty="true"><li>
			<dl newline="true" spacing="normal">
			<dt>Operation(s) affected:</dt>
			<dd>REMOVE</dd>
			<dt>Discussion:</dt>
			<dd>
	Permission to delete the		Permission to delete the
	file or directory.		file or directory.
	See <xref		See <xref target="delete-delete_child" format="default"/>
	target="delete-delete_child"/>
	for information on ACE4_DELETE and		for information on ACE4_DELETE and
	ACE4_DELETE_CHILD interact.		ACE4_DELETE_CHILD interact.
			</dd>
			</dl></li>
			</ul>
	</t>		<t>ACE4_READ_ACL</t>
	</list>		<ul empty="true"><li>
	</t>		<dl newline="true" spacing="normal">
			<dt>Operation(s) affected:</dt>
			<dd><t>GETATTR of acl, dacl, or sacl</t>
			<t>NVERIFY</t>
			<t>VERIFY</t></dd>
	<t hangText="ACE4_READ_ACL">		<dt>Discussion:</dt>
	<list style="hanging">		<dd>
	<t hangText="Operation(s) affected:">
	<list style="hanging">
	<t hangText="GETATTR of acl, dacl, or sacl" />
	<t hangText="NVERIFY" />
	<t hangText="VERIFY" />
	</list>
	</t>
	<t hangText="Discussion:">
	<vspace blankLines='1' />
	Permission to read the ACL.		Permission to read the ACL.
	</t>		</dd>
	</list>		</dl></li>
	</t>		</ul>
	<t hangText="ACE4_WRITE_ACL">		<t>ACE4_WRITE_ACL</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="SETATTR of acl and mode" />		<dd>SETATTR of acl and mode</dd>
	</list>		<dt>Discussion:</dt>
	</t>		<dd>Permission to write the acl and mode attributes.</dd>
	<t hangText="Discussion:">		</dl></li>
	<vspace blankLines='1' />		</ul>
	Permission to write the acl and mode attributes.
	</t>
	</list>
	</t>
	<t hangText="ACE4_WRITE_OWNER">		<t>ACE4_WRITE_OWNER</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="SETATTR of owner and owner_group" />		<dd>SETATTR of owner and owner_group</dd>
	</list>		<dt>Discussion:</dt>
	</t>		<dd>
	<t hangText="Discussion:">
	<vspace blankLines='1' />
	Permission to write the owner and owner_group		Permission to write the owner and owner_group
	attributes. On UNIX systems, this is the		attributes. On UNIX systems, this is the
	ability to execute chown() and chgrp().		ability to execute chown() and chgrp().
	</t>		</dd>
	</list>		</dl></li>
	</t>		</ul>
	<t hangText="ACE4_SYNCHRONIZE">		<t>ACE4_SYNCHRONIZE</t>
	<list style="hanging">		<ul empty="true"><li>
	<t hangText="Operation(s) affected:">		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>Operation(s) affected:</dt>
	<t hangText="NONE" />		<dd>NONE</dd>
	</list>		<dt>Discussion:</dt>
	</t>		<dd>
	<t hangText="Discussion:">		<t>
	<vspace blankLines='1' />
	Permission to use the file object as a		Permission to use the file object as a
	synchronization primitive for interprocess		synchronization primitive for interprocess
	communication. This permission is not enforced		communication. This permission is not enforced
	or interpreted by the NFSv4.1 server on behalf of		or interpreted by the NFSv4.1 server on behalf of
	the client.		the client.
			</t>
	<vspace blankLines='1' />		<t>
	Typically, the ACE4_SYNCHRONIZE permission is		Typically, the ACE4_SYNCHRONIZE permission is
	only meaningful on local file systems, i.e.,		only meaningful on local file systems, i.e.,
	file systems not accessed via NFSv4.1. The reason		file systems not accessed via NFSv4.1. The reason
	that the permission bit exists is that some operating		that the permission bit exists is that some operating
	environments, such as Windows, use ACE4_SYNCHRONIZE.		environments, such as Windows, use ACE4_SYNCHRONIZE.
			</t>
	<vspace blankLines='1' />		<t>
	For example, if a client copies a file that has		For example, if a client copies a file that has
	ACE4_SYNCHRONIZE set from a local file system to		ACE4_SYNCHRONIZE set from a local file system to
	an NFSv4.1 server, and then later copies the file		an NFSv4.1 server, and then later copies the file
	from the NFSv4.1 server to a local file system,		from the NFSv4.1 server to a local file system,
	it is likely that if ACE4_SYNCHRONIZE was set		it is likely that if ACE4_SYNCHRONIZE was set
	in the original file, the client will want it		in the original file, the client will want it
	set in the second copy. The first copy will not		set in the second copy. The first copy will not
	have the permission set unless the NFSv4.1 server		have the permission set unless the NFSv4.1 server
	has the means to set the ACE4_SYNCHRONIZE bit. The		has the means to set the ACE4_SYNCHRONIZE bit. The
	second copy will not have the permission set unless		second copy will not have the permission set unless
	the NFSv4.1 server has the means to retrieve the		the NFSv4.1 server has the means to retrieve the
	ACE4_SYNCHRONIZE bit.		ACE4_SYNCHRONIZE bit.
			</t>
	</t>		</dd>
	</list>		</dl></li>
	</t>		</ul>
			<t>
	</list>
	</t>
	<t>
	Server implementations need not provide the granularity		Server implementations need not provide the granularity
	of control that is implied by this list of masks. For		of control that is implied by this list of masks. For
	example, POSIX-based systems might not distinguish		example, POSIX-based systems might not distinguish
	ACE4_APPEND_DATA (the ability to append to a file) from		ACE4_APPEND_DATA (the ability to append to a file) from
	ACE4_WRITE_DATA (the ability to modify existing		ACE4_WRITE_DATA (the ability to modify existing
	contents); both masks would be tied to a single "write"		contents); both masks would be tied to a single "write"
	permission <xref target="chmod"/>. When such a server returns attr ibutes to the		permission <xref target="chmod" format="default"/>. When such a se rver returns attributes to the
	client, it would show both ACE4_APPEND_DATA and		client, it would show both ACE4_APPEND_DATA and
	ACE4_WRITE_DATA if and only if the write permission is		ACE4_WRITE_DATA if and only if the write permission is
	enabled.		enabled.
	</t>		</t>
			<t>
	<t>
	If a server receives a SETATTR request that it cannot		If a server receives a SETATTR request that it cannot
	accurately implement, it should err in the direction of		accurately implement, it should err in the direction of
	more restricted access, except in the previously		more restricted access, except in the previously
	discussed cases of execute and read. For example,		discussed cases of execute and read. For example,
	suppose a server cannot distinguish overwriting data		suppose a server cannot distinguish overwriting data
	from appending new data, as described in the previous		from appending new data, as described in the previous
	paragraph. If a client submits an ALLOW ACE where		paragraph. If a client submits an ALLOW ACE where
	ACE4_APPEND_DATA is set but ACE4_WRITE_DATA is not (or		ACE4_APPEND_DATA is set but ACE4_WRITE_DATA is not (or
	vice versa), the server should either turn off		vice versa), the server should either turn off
	ACE4_APPEND_DATA or reject the request with		ACE4_APPEND_DATA or reject the request with
	NFS4ERR_ATTRNOTSUPP.		NFS4ERR_ATTRNOTSUPP.
	</t>		</t>
	</section>		</section>
			<section anchor="delete-delete_child" numbered="true" toc="default">
	<section anchor="delete-delete_child" title="ACE4_DELETE vs. ACE4_DELE		<name>ACE4_DELETE vs. ACE4_DELETE_CHILD</name>
	TE_CHILD">		<t>
	<t>
	Two access mask bits govern the ability to delete a		Two access mask bits govern the ability to delete a
	directory entry: ACE4_DELETE on the object		directory entry: ACE4_DELETE on the object
	itself (the "target") and ACE4_DELETE_CHILD on		itself (the "target") and ACE4_DELETE_CHILD on
	the containing directory (the "parent").		the containing directory (the "parent").
	</t>		</t>
			<t>
	<t>
	Many systems also take the "sticky bit" (MODE4_SVTX)		Many systems also take the "sticky bit" (MODE4_SVTX)
	on a directory to allow unlink only to a user that		on a directory to allow unlink only to a user that
	owns either the target or the parent; on some		owns either the target or the parent; on some
	such systems the decision also depends on		such systems the decision also depends on
	whether the target is writable.		whether the target is writable.
	</t>		</t>
			<t>
	<t>		Servers <bcp14>SHOULD</bcp14> allow unlink if either ACE4_DELETE
	Servers SHOULD allow unlink if either ACE4_DELETE
	is permitted on the target, or ACE4_DELETE_CHILD is		is permitted on the target, or ACE4_DELETE_CHILD is
	permitted on the parent. (Note that this is		permitted on the parent. (Note that this is
	true even if the parent or target explicitly		true even if the parent or target explicitly
	denies one of these permissions.)		denies one of these permissions.)
	</t>		</t>
			<t>
	<t>
	If the ACLs in question neither explicitly ALLOW		If the ACLs in question neither explicitly ALLOW
	nor DENY either of the above, and if MODE4_SVTX is		nor DENY either of the above, and if MODE4_SVTX is
	not set on the parent, then the server SHOULD allow		not set on the parent, then the server <bcp14>SHOULD</bcp14> allow
	the removal if and only if ACE4_ADD_FILE is permitted.		the removal if and only if ACE4_ADD_FILE is permitted.
	In the case where MODE4_SVTX is set, the server		In the case where MODE4_SVTX is set, the server
	may also require the remover to own either the parent		may also require the remover to own either the parent
	or the target, or may require the target to be		or the target, or may require the target to be
	writable.		writable.
	</t>		</t>
			<t>
	<t>
	This allows servers to support something close to		This allows servers to support something close to
	traditional UNIX-like semantics, with ACE4_ADD_FILE		traditional UNIX-like semantics, with ACE4_ADD_FILE
	taking the place of the write bit.		taking the place of the write bit.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		<section anchor="aceflag" numbered="true" toc="default">
	<section anchor="aceflag" title="ACE flag">		<name>ACE flag</name>
	<t>		<t>
	The bitmask constants used for the flag field are as		The bitmask constants used for the flag field are as
	follows:		follows:
	<figure>		</t>
	<artwork>		<sourcecode type="xdr"><![CDATA[
	const ACE4_FILE_INHERIT_ACE = 0x00000001;		const ACE4_FILE_INHERIT_ACE = 0x00000001;
	const ACE4_DIRECTORY_INHERIT_ACE = 0x00000002;		const ACE4_DIRECTORY_INHERIT_ACE = 0x00000002;
	const ACE4_NO_PROPAGATE_INHERIT_ACE = 0x00000004;		const ACE4_NO_PROPAGATE_INHERIT_ACE = 0x00000004;
	const ACE4_INHERIT_ONLY_ACE = 0x00000008;		const ACE4_INHERIT_ONLY_ACE = 0x00000008;
	const ACE4_SUCCESSFUL_ACCESS_ACE_FLAG = 0x00000010;		const ACE4_SUCCESSFUL_ACCESS_ACE_FLAG = 0x00000010;
	const ACE4_FAILED_ACCESS_ACE_FLAG = 0x00000020;		const ACE4_FAILED_ACCESS_ACE_FLAG = 0x00000020;
	const ACE4_IDENTIFIER_GROUP = 0x00000040;		const ACE4_IDENTIFIER_GROUP = 0x00000040;
	const ACE4_INHERITED_ACE = 0x00000080;		const ACE4_INHERITED_ACE = 0x00000080;
	</artwork>		]]></sourcecode>
	</figure>		<t>
	A server need not support any of these flags. If the		A server need not support any of these flags. If the
	server supports flags that are similar to, but not		server supports flags that are similar to, but not
	exactly the same as, these flags, the implementation		exactly the same as, these flags, the implementation
	may define a mapping between the protocol-defined		may define a mapping between the protocol-defined
	flags and the implementation-defined flags.		flags and the implementation-defined flags.
	</t>		</t>
			<t>
	<t>
	For example, suppose a client tries to set an ACE with		For example, suppose a client tries to set an ACE with
	ACE4_FILE_INHERIT_ACE set but not		ACE4_FILE_INHERIT_ACE set but not
	ACE4_DIRECTORY_INHERIT_ACE. If the server does not		ACE4_DIRECTORY_INHERIT_ACE. If the server does not
	support any form of ACL inheritance, the server should		support any form of ACL inheritance, the server should
	reject the request with NFS4ERR_ATTRNOTSUPP. If the		reject the request with NFS4ERR_ATTRNOTSUPP. If the
	server supports a single "inherit ACE" flag that		server supports a single "inherit ACE" flag that
	applies to both files and directories, the server may		applies to both files and directories, the server may
	reject the request (i.e., requiring the client to set		reject the request (i.e., requiring the client to set
	both the file and directory inheritance flags). The		both the file and directory inheritance flags). The
	server may also accept the request and silently turn		server may also accept the request and silently turn
	on the ACE4_DIRECTORY_INHERIT_ACE flag.		on the ACE4_DIRECTORY_INHERIT_ACE flag.
	</t>		</t>
	<section title="Discussion of Flag Bits">		<section numbered="true" toc="default">
			<name>Discussion of Flag Bits</name>
	<t>		<dl newline="true" spacing="normal">
	<list style="hanging">		<dt>ACE4_FILE_INHERIT_ACE</dt>
	<t hangText="ACE4_FILE_INHERIT_ACE">		<dd>
	<vspace />
	Any non-directory file in any		Any non-directory file in any
	sub-directory will get this ACE		sub-directory will get this ACE
	inherited.		inherited.
	</t>		</dd>
			<dt>ACE4_DIRECTORY_INHERIT_ACE</dt>
	<t hangText="ACE4_DIRECTORY_INHERIT_ACE">		<dd>
	<vspace />		<t>
	Can be placed on a directory and indicates		Can be placed on a directory and indicates
	that this ACE should be added to each new		that this ACE should be added to each new
	directory created.		directory created.
	<vspace />		</t>
			<t>
	If this flag is set in an ACE in an ACL		If this flag is set in an ACE in an ACL
	attribute to be set on a non-directory		attribute to be set on a non-directory
	file system object, the operation		file system object, the operation
	attempting to set the ACL SHOULD fail		attempting to set the ACL <bcp14>SHOULD</bcp14> fail
	with NFS4ERR_ATTRNOTSUPP.		with NFS4ERR_ATTRNOTSUPP.
	</t>		</t>
			</dd>
	<t hangText="ACE4_NO_PROPAGATE_INHERIT_ACE">		<dt>ACE4_NO_PROPAGATE_INHERIT_ACE</dt>
	<vspace />		<dd>
	Can be placed on a directory. This flag		Can be placed on a directory. This flag
	tells the server that inheritance of this		tells the server that inheritance of this
	ACE should stop at newly created child		ACE should stop at newly created child
	directories.		directories.
	</t>		</dd>
			<dt>ACE4_INHERIT_ONLY_ACE</dt>
	<t hangText="ACE4_INHERIT_ONLY_ACE">		<dd>
	<vspace />		<t>
	Can be placed on a directory but does not		Can be placed on a directory but does not
	apply to the directory; ALLOW and DENY ACEs		apply to the directory; ALLOW and DENY ACEs
	with this bit set do not affect access to		with this bit set do not affect access to
	the directory, and AUDIT and ALARM ACEs		the directory, and AUDIT and ALARM ACEs
	with this bit set do not trigger log or		with this bit set do not trigger log or
	alarm events. Such ACEs only take effect		alarm events. Such ACEs only take effect
	once they are applied (with this bit		once they are applied (with this bit
	cleared) to newly created files and		cleared) to newly created files and
	directories as specified by the		directories as specified by the
	ACE4_FILE_INHERIT_ACE and ACE4_DIRECTORY_INHERIT_ACE		ACE4_FILE_INHERIT_ACE and ACE4_DIRECTORY_INHERIT_ACE
	flags.		flags.
	<vspace blankLines="1"/>		</t>
			<t>
	If this flag is present on an ACE, but		If this flag is present on an ACE, but
	neither ACE4_DIRECTORY_INHERIT_ACE nor		neither ACE4_DIRECTORY_INHERIT_ACE nor
	ACE4_FILE_INHERIT_ACE is present, then		ACE4_FILE_INHERIT_ACE is present, then
	an operation attempting to set such an		an operation attempting to set such an
	attribute SHOULD fail with		attribute <bcp14>SHOULD</bcp14> fail with
	NFS4ERR_ATTRNOTSUPP.		NFS4ERR_ATTRNOTSUPP.
	</t>		</t>
			</dd>
	<t hangText="ACE4_SUCCESSFUL_ACCESS_ACE_FLAG">		<dt>ACE4_SUCCESSFUL_ACCESS_ACE_FLAG and
	<vspace />		ACE4_FAILED_ACCESS_ACE_FLAG</dt>
	</t>		<dd>
	<t hangText="ACE4_FAILED_ACCESS_ACE_FLAG">		<t>
	<vspace />
	The ACE4_SUCCESSFUL_ACCESS_ACE_FLAG		The ACE4_SUCCESSFUL_ACCESS_ACE_FLAG
	(SUCCESS) and ACE4_FAILED_ACCESS_ACE_FLAG		(SUCCESS) and ACE4_FAILED_ACCESS_ACE_FLAG
	(FAILED) flag bits may be set only on		(FAILED) flag bits may be set only on
	ACE4_SYSTEM_AUDIT_ACE_TYPE (AUDIT) and		ACE4_SYSTEM_AUDIT_ACE_TYPE (AUDIT) and
	ACE4_SYSTEM_ALARM_ACE_TYPE (ALARM) ACE		ACE4_SYSTEM_ALARM_ACE_TYPE (ALARM) ACE
	types. If during the processing of the		types. If during the processing of the
	file's ACL, the server encounters an AUDIT		file's ACL, the server encounters an AUDIT
	or ALARM ACE that matches the principal		or ALARM ACE that matches the principal
	attempting the OPEN, the server notes that		attempting the OPEN, the server notes that
	fact, and the presence, if any, of the		fact, and the presence, if any, of the
	skipping to change at line 9292 ¶		skipping to change at line 9524 ¶
	the SUCCESS flag was set for a matching		the SUCCESS flag was set for a matching
	AUDIT or ALARM ACE, then the appropriate		AUDIT or ALARM ACE, then the appropriate
	AUDIT or ALARM event occurs. If the		AUDIT or ALARM event occurs. If the
	operation failed, and if the FAILED flag		operation failed, and if the FAILED flag
	was set for the matching AUDIT or ALARM		was set for the matching AUDIT or ALARM
	ACE, then the appropriate AUDIT or ALARM		ACE, then the appropriate AUDIT or ALARM
	event occurs. Either or both of the		event occurs. Either or both of the
	SUCCESS or FAILED can be set, but if		SUCCESS or FAILED can be set, but if
	neither is set, the AUDIT or ALARM ACE is		neither is set, the AUDIT or ALARM ACE is
	not useful.		not useful.
	</t>		</t>
			<t>
	<t hangText="">
	The previously described processing		The previously described processing
	applies to ACCESS operations even when		applies to ACCESS operations even when
	they return NFS4_OK. For the purposes of		they return NFS4_OK. For the purposes of
	AUDIT and ALARM, we consider an ACCESS		AUDIT and ALARM, we consider an ACCESS
	operation to be a "failure" if it fails		operation to be a "failure" if it fails
	to return a bit that was requested and		to return a bit that was requested and
	supported.		supported.</t>
	</t>		</dd>
			<dt>ACE4_IDENTIFIER_GROUP</dt>
	<t hangText="ACE4_IDENTIFIER_GROUP">		<dd>
	<vspace />
	Indicates that the "who" refers to a GROUP		Indicates that the "who" refers to a GROUP
	as defined under UNIX or a GROUP ACCOUNT		as defined under UNIX or a GROUP ACCOUNT
	as defined under Windows. Clients and		as defined under Windows. Clients and
	servers MUST ignore the		servers <bcp14>MUST</bcp14> ignore the
	ACE4_IDENTIFIER_GROUP flag on ACEs with a		ACE4_IDENTIFIER_GROUP flag on ACEs with a
	who value equal to one of the special		who value equal to one of the special
	identifiers outlined in		identifiers outlined in
	<xref target="acewho" />.		<xref target="acewho" format="default"/>.
	</t>		</dd>
			<dt>ACE4_INHERITED_ACE</dt>
	<t hangText="ACE4_INHERITED_ACE">		<dd>
	<vspace />
	Indicates that this ACE is inherited from		Indicates that this ACE is inherited from
	a parent directory. A server that supports		a parent directory. A server that supports
	automatic inheritance will place		automatic inheritance will place
	this flag on any ACEs inherited from the		this flag on any ACEs inherited from the
	parent directory when creating a new		parent directory when creating a new
	object. Client applications will use this		object. Client applications will use this
	to perform automatic inheritance.		to perform automatic inheritance.
	Clients and servers MUST clear this		Clients and servers <bcp14>MUST</bcp14> clear this
	bit in the acl attribute; it may only		bit in the acl attribute; it may only
	be used in the dacl and sacl attributes.		be used in the dacl and sacl attributes.
	</t>		</dd>
	</list>		</dl>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="acewho" numbered="true" toc="default">
	<section title="ACE Who" anchor="acewho">		<name>ACE Who</name>
	<t>		<t>
	The &quot;who&quot; field of an ACE is an identifier that		The "who" field of an ACE is an identifier that
	specifies the principal or principals to whom the ACE		specifies the principal or principals to whom the ACE
	applies. It may refer to a user or a group, with the flag		applies. It may refer to a user or a group, with the flag
	bit ACE4_IDENTIFIER_GROUP specifying which.		bit ACE4_IDENTIFIER_GROUP specifying which.
	</t>		</t>
	<t>		<t>
	There are several special identifiers that need to be		There are several special identifiers that need to be
	understood universally, rather than in the context of a		understood universally, rather than in the context of a
	particular DNS domain. Some of these identifiers cannot be		particular DNS domain. Some of these identifiers cannot be
	understood when an NFS client accesses the server, but		understood when an NFS client accesses the server, but
	have meaning when a local process accesses the file. The		have meaning when a local process accesses the file. The
	ability to display and modify these permissions is		ability to display and modify these permissions is
	permitted over NFS, even if none of the access methods on		permitted over NFS, even if none of the access methods on
	the server understands the identifiers.		the server understands the identifiers.
	</t>		</t>
	<texttable anchor="specialwho">		<table anchor="specialwho" align="center">
	<ttcol>Who</ttcol>		<thead>
	<ttcol>Description</ttcol>		<tr>
	<c>OWNER</c>		<th align="left">Who</th>
	<c>		<th align="left">Description</th>
			</tr>
			</thead>
			<tbody>
			<tr>
			<td align="left">OWNER</td>
			<td align="left">
	The owner of the file.		The owner of the file.
	</c>		</td>
	<c>GROUP</c>		</tr>
	<c>		<tr>
			<td align="left">GROUP</td>
			<td align="left">
	The group associated with the file.		The group associated with the file.
	</c>		</td>
	<c>EVERYONE</c>		</tr>
	<c>		<tr>
			<td align="left">EVERYONE</td>
			<td align="left">
	The world, including the owner and owning group.		The world, including the owner and owning group.
	</c>		</td>
	<c>INTERACTIVE</c>		</tr>
	<c>		<tr>
			<td align="left">INTERACTIVE</td>
			<td align="left">
	Accessed from an interactive terminal.		Accessed from an interactive terminal.
	</c>		</td>
	<c>NETWORK</c>		</tr>
	<c>		<tr>
			<td align="left">NETWORK</td>
			<td align="left">
	Accessed via the network.		Accessed via the network.
	</c>		</td>
	<c>DIALUP</c>		</tr>
	<c>		<tr>
			<td align="left">DIALUP</td>
			<td align="left">
	Accessed as a dialup user to the server.		Accessed as a dialup user to the server.
	</c>		</td>
	<c>BATCH</c>		</tr>
	<c>		<tr>
			<td align="left">BATCH</td>
			<td align="left">
	Accessed from a batch job.		Accessed from a batch job.
	</c>		</td>
	<c>ANONYMOUS</c>		</tr>
	<c>		<tr>
			<td align="left">ANONYMOUS</td>
			<td align="left">
	Accessed without any authentication.		Accessed without any authentication.
	</c>		</td>
	<c>AUTHENTICATED</c>		</tr>
	<c>		<tr>
			<td align="left">AUTHENTICATED</td>
			<td align="left">
	Any authenticated user (opposite of		Any authenticated user (opposite of
	ANONYMOUS).		ANONYMOUS).
	</c>		</td>
	<c>SERVICE</c>		</tr>
	<c>		<tr>
			<td align="left">SERVICE</td>
			<td align="left">
	Access from a system service.		Access from a system service.
	</c>		</td>
	</texttable>		</tr>
	<t>		</tbody>
			</table>
			<t>
	To avoid conflict, these special identifiers are		To avoid conflict, these special identifiers are
	distinguished by an appended "@" and should appear in the		distinguished by an appended "@" and should appear in the
	form "xxxx@" (with no domain name after the "@"), for		form "xxxx@" (with no domain name after the "@"), for
	example, ANONYMOUS@.		example, ANONYMOUS@.
	</t>		</t>
	<t>		<t>
	The ACE4_IDENTIFIER_GROUP flag MUST be ignored on		The ACE4_IDENTIFIER_GROUP flag <bcp14>MUST</bcp14> be ignored on
	entries with these special identifiers. When encoding		entries with these special identifiers. When encoding
	entries with these special identifiers, the		entries with these special identifiers, the
	ACE4_IDENTIFIER_GROUP flag SHOULD be set to zero.		ACE4_IDENTIFIER_GROUP flag <bcp14>SHOULD</bcp14> be set to zero.
	</t>		</t>
			<section numbered="true" toc="default">
	<section title="Discussion of EVERYONE@">		<name>Discussion of EVERYONE@</name>
	<t>		<t>
	It is important to note that "EVERYONE@" is not		It is important to note that "EVERYONE@" is not
	equivalent to the UNIX "other" entity. This is		equivalent to the UNIX "other" entity. This is
	because, by definition, UNIX "other" does not include		because, by definition, UNIX "other" does not include
	the owner or owning group of a file. "EVERYONE@" means		the owner or owning group of a file. "EVERYONE@" means
	literally everyone, including the owner or owning		literally everyone, including the owner or owning
	group.		group.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		</section>
	</section>		<section anchor="attrdef_dacl" numbered="true" toc="default">
	<section anchor="attrdef_dacl"		<name>Attribute 58: dacl</name>
	title="Attribute 58: dacl">		<t>
	<t>
	The dacl attribute is like the acl attribute,		The dacl attribute is like the acl attribute,
	but dacl allows		but dacl allows
	just ALLOW and DENY ACEs. The dacl		just ALLOW and DENY ACEs. The dacl
	attribute supports automatic inheritance (see		attribute supports automatic inheritance (see
	<xref target="auto_inherit" />).		<xref target="auto_inherit" format="default"/>).
	</t>		</t>
	</section>		</section>
			<section anchor="attrdef_sacl" numbered="true" toc="default">
	<section anchor="attrdef_sacl"		<name>Attribute 59: sacl</name>
	title="Attribute 59: sacl">		<t>
	<t>
	The sacl attribute is like the acl attribute,		The sacl attribute is like the acl attribute,
	but sacl allows		but sacl allows
	just AUDIT and ALARM ACEs. The sacl		just AUDIT and ALARM ACEs. The sacl
	attribute supports automatic inheritance (see		attribute supports automatic inheritance (see
	<xref target="auto_inherit" />).		<xref target="auto_inherit" format="default"/>).
	</t>		</t>
	</section>		</section>
			<section anchor="attrdef_mode" numbered="true" toc="default">
	<section anchor="attrdef_mode"		<name>Attribute 33: mode</name>
	title="Attribute 33: mode">		<t>
	<t>
	The NFSv4.1 mode attribute is based on the UNIX mode		The NFSv4.1 mode attribute is based on the UNIX mode
	bits. The following bits are defined:		bits. The following bits are defined:
	</t>		</t>
			<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	const MODE4_SUID = 0x800; /* set user id on execution */		const MODE4_SUID = 0x800; /* set user id on execution */
	const MODE4_SGID = 0x400; /* set group id on execution */		const MODE4_SGID = 0x400; /* set group id on execution */
	const MODE4_SVTX = 0x200; /* save text even after use */		const MODE4_SVTX = 0x200; /* save text even after use */
	const MODE4_RUSR = 0x100; /* read permission: owner */		const MODE4_RUSR = 0x100; /* read permission: owner */
	const MODE4_WUSR = 0x080; /* write permission: owner */		const MODE4_WUSR = 0x080; /* write permission: owner */
	const MODE4_XUSR = 0x040; /* execute permission: owner */		const MODE4_XUSR = 0x040; /* execute permission: owner */
	const MODE4_RGRP = 0x020; /* read permission: group */		const MODE4_RGRP = 0x020; /* read permission: group */
	const MODE4_WGRP = 0x010; /* write permission: group */		const MODE4_WGRP = 0x010; /* write permission: group */
	const MODE4_XGRP = 0x008; /* execute permission: group */		const MODE4_XGRP = 0x008; /* execute permission: group */
	const MODE4_ROTH = 0x004; /* read permission: other */		const MODE4_ROTH = 0x004; /* read permission: other */
	const MODE4_WOTH = 0x002; /* write permission: other */		const MODE4_WOTH = 0x002; /* write permission: other */
	const MODE4_XOTH = 0x001; /* execute permission: other */		const MODE4_XOTH = 0x001; /* execute permission: other */
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	Bits MODE4_RUSR, MODE4_WUSR, and MODE4_XUSR apply to the		Bits MODE4_RUSR, MODE4_WUSR, and MODE4_XUSR apply to the
	principal identified in the owner attribute. Bits MODE4_RGRP,		principal identified in the owner attribute. Bits MODE4_RGRP,
	MODE4_WGRP, and MODE4_XGRP apply to principals identified in		MODE4_WGRP, and MODE4_XGRP apply to principals identified in
	the owner_group attribute but who are not identified in the		the owner_group attribute but who are not identified in the
	owner attribute. Bits MODE4_ROTH, MODE4_WOTH, and MODE4_XOTH apply		owner attribute. Bits MODE4_ROTH, MODE4_WOTH, and MODE4_XOTH apply
	to any principal that does not match that in the owner		to any principal that does not match that in the owner
	attribute and does not have a group matching that of the		attribute and does not have a group matching that of the
	owner_group attribute.		owner_group attribute.
	</t>		</t>
	<t>		<t>
	Bits within a mode other than those specified above		Bits within a mode other than those specified above
	are not defined by this protocol. A server		are not defined by this protocol. A server
	MUST NOT return bits other than those defined above in a		<bcp14>MUST NOT</bcp14> return bits other than those defined above in
	GETATTR or READDIR operation, and it MUST return NFS4ERR_INVAL		a
			GETATTR or READDIR operation, and it <bcp14>MUST</bcp14> return NFS4ER
			R_INVAL
	if bits other than those defined above are set in a SETATTR,		if bits other than those defined above are set in a SETATTR,
	CREATE, OPEN, VERIFY, or NVERIFY operation.		CREATE, OPEN, VERIFY, or NVERIFY operation.
	</t>		</t>
	</section>		</section>
	<section anchor="attrdef_mode_set_masked"		<section anchor="attrdef_mode_set_masked" numbered="true" toc="default">
	title="Attribute 74: mode_set_masked">		<name>Attribute 74: mode_set_masked</name>
	<t>		<t>
	The mode_set_masked attribute is a write-only attribute		The mode_set_masked attribute is a write-only attribute
	that allows individual bits in the mode attribute to be		that allows individual bits in the mode attribute to be
	set or reset, without changing others. It allows, for		set or reset, without changing others. It allows, for
	example, the bits MODE4_SUID, MODE4_SGID, and MODE4_SVTX		example, the bits MODE4_SUID, MODE4_SGID, and MODE4_SVTX
	to be modified while leaving unmodified any of the		to be modified while leaving unmodified any of the
	nine low-order mode bits devoted to permissions.		nine low-order mode bits devoted to permissions.
	</t>		</t>
	<t>		<t>
	In such instances that the nine low-order bits are left		In such instances that the nine low-order bits are left
	unmodified, then neither the acl nor the dacl attribute		unmodified, then neither the acl nor the dacl attribute
	should be automatically modified as discussed in		should be automatically modified as discussed in
	<xref target="setattr" />.		<xref target="setattr" format="default"/>.
	</t>		</t>
	<t>		<t>
	The mode_set_masked attribute consists of two words,		The mode_set_masked attribute consists of two words,
	each in the form of a mode4. The first consists of the		each in the form of a mode4. The first consists of the
	value to be applied to the current mode value and the		value to be applied to the current mode value and the
	second is a mask. Only bits set to one in the mask word		second is a mask. Only bits set to one in the mask word
	are changed (set or reset) in the file's mode. All		are changed (set or reset) in the file's mode. All
	other bits in the mode remain unchanged. Bits in the		other bits in the mode remain unchanged. Bits in the
	first word that correspond to bits that are zero in		first word that correspond to bits that are zero in
	the mask are ignored, except that undefined bits are		the mask are ignored, except that undefined bits are
	checked for validity and can result in NFS4ERR_INVAL as		checked for validity and can result in NFS4ERR_INVAL as
	described below.		described below.
	</t>		</t>
	<t>		<t>
	The mode_set_masked attribute is only valid in a SETATTR		The mode_set_masked attribute is only valid in a SETATTR
	operation. If it is used in a CREATE or OPEN operation, the		operation. If it is used in a CREATE or OPEN operation, the
	server MUST return NFS4ERR_INVAL.		server <bcp14>MUST</bcp14> return NFS4ERR_INVAL.
	</t>		</t>
	<t>		<t>
	Bits not defined as valid in the mode attribute are not		Bits not defined as valid in the mode attribute are not
	valid in either word of the mode_set_masked attribute.		valid in either word of the mode_set_masked attribute.
	The server MUST return NFS4ERR_INVAL		The server <bcp14>MUST</bcp14> return NFS4ERR_INVAL
	if any such bits are set to one in a SETATTR.		if any such bits are set to one in a SETATTR.
	If the mode and		If the mode and
	mode_set_masked attributes are both specified in the		mode_set_masked attributes are both specified in the
	same SETATTR, the server MUST also return NFS4ERR_INVAL.		same SETATTR, the server <bcp14>MUST</bcp14> also return NFS4ERR_INVAL
	</t>		.
			</t>
			</section>
	</section>		</section>
			<section numbered="true" toc="default">
	</section>		<name>Common Methods</name>
			<t>
	<section title="Common Methods">
	<t>
	The requirements in this section will be referred to in future		The requirements in this section will be referred to in future
	sections, especially <xref target="aclreqs" />.		sections, especially <xref target="aclreqs" format="default"/>.
	</t>		</t>
	<section title="Interpreting an ACL" anchor="useacl">		<section anchor="useacl" numbered="true" toc="default">
	<section title="Server Considerations" anchor="serverinterp">		<name>Interpreting an ACL</name>
	<t>		<section anchor="serverinterp" numbered="true" toc="default">
			<name>Server Considerations</name>
			<t>
	The server uses the algorithm described in		The server uses the algorithm described in
	<xref target="attrdef_acl"/> to determine whether an ACL		<xref target="attrdef_acl" format="default"/> to determine whether an ACL
	allows access to an object. However, the ACL might not be		allows access to an object. However, the ACL might not be
	the sole determiner of access. For example:		the sole determiner of access. For example:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	In the case of a file system exported as read-only,		In the case of a file system exported as read-only,
	the server may deny write access even though		the server may deny write access even though
	an object's ACL grants it.		an object's ACL grants it.
	</t>		</li>
			<li>
	<t>		Server implementations <bcp14>MAY</bcp14> grant ACE4_WRITE_ACL
	Server implementations MAY grant ACE4_WRITE_ACL
	and ACE4_READ_ACL permissions to prevent		and ACE4_READ_ACL permissions to prevent
	a situation from arising in which there is no valid		a situation from arising in which there is no valid
	way to ever modify the ACL.		way to ever modify the ACL.
	</t>		</li>
			<li>
	<t>
	All servers will allow a user the ability to read		All servers will allow a user the ability to read
	the data of the file when only the execute		the data of the file when only the execute
	permission is granted (i.e., if the ACL denies the		permission is granted (i.e., if the ACL denies the
	user the ACE4_READ_DATA access and allows the user		user the ACE4_READ_DATA access and allows the user
	ACE4_EXECUTE, the server will allow the user to		ACE4_EXECUTE, the server will allow the user to
	read the data of the file).		read the data of the file).
	</t>		</li>
			<li>
	<t>
	Many servers have the notion of owner-override in		Many servers have the notion of owner-override in
	which the owner of the object is allowed to		which the owner of the object is allowed to
	override accesses that are denied by the ACL.		override accesses that are denied by the ACL.
	This may be helpful, for example, to allow users		This may be helpful, for example, to allow users
	continued access to open files on which the		continued access to open files on which the
	permissions have changed.		permissions have changed.
	</t>		</li>
			<li>
	<t>
	Many servers have the notion of a		Many servers have the notion of a
	&quot;superuser&quot; that has privileges beyond		"superuser" that has privileges beyond
	an ordinary user. The superuser may be able		an ordinary user. The superuser may be able
	to read or write data or metadata in ways that would		to read or write data or metadata in ways that would
	not be permitted by the ACL.		not be permitted by the ACL.
	</t>		</li>
			<li>
	<t>
	A retention attribute might also block access otherwise		A retention attribute might also block access otherwise
	allowed by ACLs (see <xref target="retention"/>).		allowed by ACLs (see <xref target="retention" format="default"/>
	</t>		).
			</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section anchor="clientinterp" numbered="true" toc="default">
			<name>Client Considerations</name>
	<section title="Client Considerations" anchor="clientinterp">		<t>
	<t>		Clients <bcp14>SHOULD NOT</bcp14> do their own access checks based o
	Clients SHOULD NOT do their own access checks based on		n
	their interpretation of the ACL, but rather use the OPEN and		their interpretation of the ACL, but rather use the OPEN and
	ACCESS operations to do access checks. This allows the		ACCESS operations to do access checks. This allows the
	client to act on the results of having the server		client to act on the results of having the server
	determine whether or not access should be granted based on		determine whether or not access should be granted based on
	its interpretation of the ACL.		its interpretation of the ACL.
	</t>		</t>
			<t>
	<t>
	Clients must be aware of situations in which an object's		Clients must be aware of situations in which an object's
	ACL will define a certain access even though the server		ACL will define a certain access even though the server
	will not enforce it. In general, but especially in these		will not enforce it. In general, but especially in these
	situations, the client needs to do its part in the		situations, the client needs to do its part in the
	enforcement of access as defined by the ACL. To do this,		enforcement of access as defined by the ACL. To do this,
	the client MAY send the appropriate ACCESS operation		the client <bcp14>MAY</bcp14> send the appropriate ACCESS operation
	prior to servicing the request of the user or application		prior to servicing the request of the user or application
	in order to determine whether the user or application		in order to determine whether the user or application
	should be granted the access requested. For examples in		should be granted the access requested. For examples in
	which the ACL may define accesses that the server doesn't		which the ACL may define accesses that the server doesn't
	enforce, see <xref target="serverinterp"/>.		enforce, see <xref target="serverinterp" format="default"/>.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		<section anchor="computemode" numbered="true" toc="default">
			<name>Computing a Mode Attribute from an ACL</name>
	<section title="Computing a Mode Attribute from an ACL"		<t>
	anchor="computemode">
	<t>
	The following method can be used to calculate the MODE4_R*,		The following method can be used to calculate the MODE4_R*,
	MODE4_W*, and MODE4_X* bits of a mode attribute, based upon		MODE4_W*, and MODE4_X* bits of a mode attribute, based upon
	an ACL.		an ACL.
	</t>		</t>
			<t>
	<t>
	First, for each of the special identifiers OWNER@, GROUP@, and		First, for each of the special identifiers OWNER@, GROUP@, and
	EVERYONE@, evaluate the ACL in order, considering only ALLOW		EVERYONE@, evaluate the ACL in order, considering only ALLOW
	and DENY ACEs for the identifier EVERYONE@ and for the		and DENY ACEs for the identifier EVERYONE@ and for the
	identifier under consideration. The result of the evaluation		identifier under consideration. The result of the evaluation
	will be an NFSv4 ACL mask showing exactly which bits are		will be an NFSv4 ACL mask showing exactly which bits are
	permitted to that identifier.		permitted to that identifier.
	</t>		</t>
			<t>
	<t>
	Then translate the calculated mask for OWNER@, GROUP@, and		Then translate the calculated mask for OWNER@, GROUP@, and
	EVERYONE@ into mode bits for, respectively, the user, group,		EVERYONE@ into mode bits for, respectively, the user, group,
	and other, as follows:		and other, as follows:
	<list style="numbers">		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	Set the read bit (MODE4_RUSR, MODE4_RGRP, or		Set the read bit (MODE4_RUSR, MODE4_RGRP, or
	MODE4_ROTH) if and only if ACE4_READ_DATA is set in		MODE4_ROTH) if and only if ACE4_READ_DATA is set in
	the corresponding mask.		the corresponding mask.
	</t>		</li>
			<li>
	<t>
	Set the write bit (MODE4_WUSR, MODE4_WGRP, or		Set the write bit (MODE4_WUSR, MODE4_WGRP, or
	MODE4_WOTH) if and only if ACE4_WRITE_DATA and		MODE4_WOTH) if and only if ACE4_WRITE_DATA and
	ACE4_APPEND_DATA are both set in the corresponding		ACE4_APPEND_DATA are both set in the corresponding
	mask.		mask.
	</t>		</li>
			<li>
	<t>
	Set the execute bit (MODE4_XUSR, MODE4_XGRP, or		Set the execute bit (MODE4_XUSR, MODE4_XGRP, or
	MODE4_XOTH), if and only if ACE4_EXECUTE is set in the		MODE4_XOTH), if and only if ACE4_EXECUTE is set in the
	corresponding mask.		corresponding mask.
	</t>		</li>
	</list>		</ol>
	</t>		<section numbered="true" toc="default">
	<section title="Discussion">		<name>Discussion</name>
	<t>		<t>
	Some server implementations also add bits permitted to		Some server implementations also add bits permitted to
	named users and groups to the group bits (MODE4_RGRP,		named users and groups to the group bits (MODE4_RGRP,
	MODE4_WGRP, and MODE4_XGRP).		MODE4_WGRP, and MODE4_XGRP).
	</t>		</t>
	<t>		<t>
	Implementations are discouraged from doing this, because		Implementations are discouraged from doing this, because
	it has been found to cause confusion for users who see		it has been found to cause confusion for users who see
	members of a file's group denied access that the mode		members of a file's group denied access that the mode
	bits appear to allow. (The presence of DENY ACEs may also		bits appear to allow. (The presence of DENY ACEs may also
	lead to such behavior, but DENY ACEs are expected to be		lead to such behavior, but DENY ACEs are expected to be
	more rarely used.)		more rarely used.)
	</t>		</t>
	<t>		<t>
	The same user confusion seen when fetching the mode also		The same user confusion seen when fetching the mode also
	results if setting the mode does not effectively control		results if setting the mode does not effectively control
	permissions for the owner, group, and other users; this		permissions for the owner, group, and other users; this
	motivates some of the requirements that follow.		motivates some of the requirements that follow.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		</section>
	</section>		<section anchor="aclreqs" numbered="true" toc="default">
			<name>Requirements</name>
	<section title="Requirements" anchor="aclreqs">		<t>
	<t>
	The server that supports both mode and ACL must take care to		The server that supports both mode and ACL must take care to
	synchronize the MODE4_*USR, MODE4_*GRP, and MODE4_*OTH bits with		synchronize the MODE4_*USR, MODE4_*GRP, and MODE4_*OTH bits with
	the ACEs that have respective who fields of "OWNER@", "GROUP@",		the ACEs that have respective who fields of "OWNER@", "GROUP@",
	and "EVERYONE@". This way, the client can see if semantically equivalent		and "EVERYONE@". This way, the client can see if semantically equivalent
	access permissions exist whether the client asks for the owner,		access permissions exist whether the client asks for the owner,
	owner_group, and mode attributes or for just the ACL.		owner_group, and mode attributes or for just the ACL.
	</t>		</t>
	<t>		<t>
	In this section, much is made of the methods in <xref		In this section, much is made of the methods in <xref target="computemod
	target="computemode" /		e" format="default"/>. Many requirements refer to this section.
	>. Many requirements refer to this section.
	But note that the methods have behaviors specified with		But note that the methods have behaviors specified with
	&quot;SHOULD&quot;. This is intentional, to avoid invalidating		"<bcp14>SHOULD</bcp14>". This is intentional, to avoid invalidating
	existing implementations that compute the mode according to the		existing implementations that compute the mode according to the
	withdrawn POSIX ACL draft (1003.1e draft 17), rather than by		withdrawn POSIX ACL draft (1003.1e draft 17), rather than by
	actual permissions on owner, group, and other.		actual permissions on owner, group, and other.
	</t>		</t>
	<section title="Setting the Mode and/or ACL Attributes"		<section anchor="setattr" numbered="true" toc="default">
	anchor="setattr">		<name>Setting the Mode and/or ACL Attributes</name>
	<t>		<t>
	In the case where a server supports the sacl or		In the case where a server supports the sacl or
	dacl attribute, in addition to the acl attribute,		dacl attribute, in addition to the acl attribute,
	the server MUST fail a request to set the acl		the server <bcp14>MUST</bcp14> fail a request to set the acl
	attribute simultaneously with a dacl or sacl		attribute simultaneously with a dacl or sacl
	attribute. The error to be given is NFS4ERR_ATTRNOTSUPP.		attribute. The error to be given is NFS4ERR_ATTRNOTSUPP.
	</t>		</t>
	<section title="Setting Mode and not ACL" anchor="setmode">		<section anchor="setmode" numbered="true" toc="default">
	<t>		<name>Setting Mode and not ACL</name>
			<t>
	When any of the nine low-order mode bits		When any of the nine low-order mode bits
	are subject to change, either because the mode		are subject to change, either because the mode
	attribute was set or because the mode_set_masked		attribute was set or because the mode_set_masked
	attribute was set and the mask included one or more		attribute was set and the mask included one or more
	bits from the nine low-order mode bits,		bits from the nine low-order mode bits,
	and no ACL attribute is explicitly		and no ACL attribute is explicitly
	set, the acl and dacl attributes must be modified		set, the acl and dacl attributes must be modified
	in accordance with the updated value of those bits.		in accordance with the updated value of those bits.
	This must happen		This must happen
	even if the value of the low-order bits		even if the value of the low-order bits
	is the same after the mode is set as before.		is the same after the mode is set as before.
	</t>		</t>
	<t>		<t>
	Note that any AUDIT or ALARM ACEs (hence any ACEs in the		Note that any AUDIT or ALARM ACEs (hence any ACEs in the
	sacl attribute) are unaffected by changes to the mode.		sacl attribute) are unaffected by changes to the mode.
	</t>		</t>
	<t>		<t>
	In cases in which the permissions bits are subject to		In cases in which the permissions bits are subject to
	change, the acl and dacl attributes		change, the acl and dacl attributes
	MUST be modified such that the mode computed via the		<bcp14>MUST</bcp14> be modified such that the mode computed via the
	method in		method in
	<xref target="computemode" />		<xref target="computemode" format="default"/>
	yields the low-order nine bits (MODE4_R*, MODE4_W*,		yields the low-order nine bits (MODE4_R*, MODE4_W*,
	MODE4_X*) of the mode attribute as modified by the		MODE4_X*) of the mode attribute as modified by the
	attribute change. The ACL attributes		attribute change. The ACL attributes
	SHOULD also be modified such that:		<bcp14>SHOULD</bcp14> also be modified such that:
	<list style="numbers">		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	If MODE4_RGRP is not set, entities explicitly		If MODE4_RGRP is not set, entities explicitly
	listed in the ACL other than OWNER@ and EVERYONE@		listed in the ACL other than OWNER@ and EVERYONE@
	SHOULD NOT be granted ACE4_READ_DATA.		<bcp14>SHOULD NOT</bcp14> be granted ACE4_READ_DATA.
	</t>		</li>
	<t>		<li>
	If MODE4_WGRP is not set, entities explicitly		If MODE4_WGRP is not set, entities explicitly
	listed in the ACL other than OWNER@ and		listed in the ACL other than OWNER@ and
	EVERYONE@ SHOULD NOT be granted		EVERYONE@ <bcp14>SHOULD NOT</bcp14> be granted
	ACE4_WRITE_DATA or ACE4_APPEND_DATA.		ACE4_WRITE_DATA or ACE4_APPEND_DATA.
	</t>		</li>
	<t>		<li>
	If MODE4_XGRP is not set, entities explicitly		If MODE4_XGRP is not set, entities explicitly
	listed in the ACL other than OWNER@ and EVERYONE@		listed in the ACL other than OWNER@ and EVERYONE@
	SHOULD NOT be granted ACE4_EXECUTE.		<bcp14>SHOULD NOT</bcp14> be granted ACE4_EXECUTE.
	</t>		</li>
	</list>		</ol>
			<t>
	Access mask bits other than those listed above, appearing		Access mask bits other than those listed above, appearing
	in ALLOW ACEs, MAY also be disabled.		in ALLOW ACEs, <bcp14>MAY</bcp14> also be disabled.
	</t>		</t>
	<t>		<t>
	Note that ACEs with the flag ACE4_INHERIT_ONLY_ACE set do		Note that ACEs with the flag ACE4_INHERIT_ONLY_ACE set do
	not affect the permissions of the ACL itself, nor do ACEs		not affect the permissions of the ACL itself, nor do ACEs
	of the type AUDIT and ALARM. As such, it is desirable to		of the type AUDIT and ALARM. As such, it is desirable to
	leave these ACEs unmodified when modifying the ACL		leave these ACEs unmodified when modifying the ACL
	attributes.		attributes.
	</t>		</t>
	<t>		<t>
	Also note that the requirement may be met by		Also note that the requirement may be met by
	discarding the acl and dacl, in favor of an ACL		discarding the acl and dacl, in favor of an ACL
	that represents the mode and only the mode. This is		that represents the mode and only the mode. This is
	permitted, but it is preferable for a server to		permitted, but it is preferable for a server to
	preserve as much of the ACL as possible without		preserve as much of the ACL as possible without
	violating the above requirements. Discarding the		violating the above requirements. Discarding the
	ACL makes it effectively impossible for a file		ACL makes it effectively impossible for a file
	created with a mode attribute to inherit an ACL		created with a mode attribute to inherit an ACL
	(see <xref target="aclcreate" />).		(see <xref target="aclcreate" format="default"/>).
	</t>		</t>
	</section>		</section>
	<section title="Setting ACL and Not Mode"		<section anchor="settingacl" numbered="true" toc="default">
	anchor="settingacl">		<name>Setting ACL and Not Mode</name>
	<t>		<t>
	When setting the acl or dacl and not setting the		When setting the acl or dacl and not setting the
	mode or mode_set_masked attributes, the permission		mode or mode_set_masked attributes, the permission
	bits of the mode need to be derived from the ACL.		bits of the mode need to be derived from the ACL.
	In this case, the ACL attribute SHOULD be set as		In this case, the ACL attribute <bcp14>SHOULD</bcp14> be set as
	given. The nine low-order bits of the mode		given. The nine low-order bits of the mode
	attribute (MODE4_R*, MODE4_W*, MODE4_X*) MUST be		attribute (MODE4_R*, MODE4_W*, MODE4_X*) <bcp14>MUST</bcp14> be
	modified to match the result of the method in		modified to match the result of the method in
	<xref target="computemode" />. The three high-order bits		<xref target="computemode" format="default"/>. The three high-order b its
	of the mode (MODE4_SUID, MODE4_SGID, MODE4_SVTX)		of the mode (MODE4_SUID, MODE4_SGID, MODE4_SVTX)
	SHOULD remain unchanged.		<bcp14>SHOULD</bcp14> remain unchanged.
	</t>		</t>
	</section>		</section>
	<section title="Setting Both ACL and Mode" anchor="setboth">		<section anchor="setboth" numbered="true" toc="default">
	<t>		<name>Setting Both ACL and Mode</name>
			<t>
	When setting both the mode (includes use of either the		When setting both the mode (includes use of either the
	mode attribute or the mode_set_masked attribute)		mode attribute or the mode_set_masked attribute)
	and the acl or dacl attributes in the		and the acl or dacl attributes in the
	same operation, the attributes MUST be applied in this		same operation, the attributes <bcp14>MUST</bcp14> be applied in thi s
	order: mode (or mode_set_masked), then ACL. The		order: mode (or mode_set_masked), then ACL. The
	mode-related attribute is set as given,		mode-related attribute is set as given,
	then the ACL attribute is set as given, possibly changing		then the ACL attribute is set as given, possibly changing
	the final mode, as described above in		the final mode, as described above in
	<xref target="settingacl" />.		<xref target="settingacl" format="default"/>.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		<section numbered="true" toc="default">
	<section title="Retrieving the Mode and/or ACL Attributes">		<name>Retrieving the Mode and/or ACL Attributes</name>
	<t>		<t>
	This section applies only to servers that support both the		This section applies only to servers that support both the
	mode and ACL attributes.		mode and ACL attributes.
	</t>		</t>
	<t>		<t>
	Some server implementations may have a concept of		Some server implementations may have a concept of
	&quot;objects without ACLs&quot;, meaning that all permissions		"objects without ACLs", meaning that all permissions
	are granted and denied according to the mode attribute and		are granted and denied according to the mode attribute and
	that no ACL attribute is stored for that object. If an ACL		that no ACL attribute is stored for that object. If an ACL
	attribute is requested of such a server, the server SHOULD		attribute is requested of such a server, the server <bcp14>SHOULD</bcp 14>
	return an ACL that does not conflict with the mode; that is to		return an ACL that does not conflict with the mode; that is to
	say, the ACL returned SHOULD represent the nine low-order bits		say, the ACL returned <bcp14>SHOULD</bcp14> represent the nine low-ord er bits
	of the mode attribute (MODE4_R*, MODE4_W*, MODE4_X*) as		of the mode attribute (MODE4_R*, MODE4_W*, MODE4_X*) as
	described in <xref target="computemode" />.		described in <xref target="computemode" format="default"/>.
	</t>		</t>
	<t>		<t>
	For other server implementations, the ACL attribute is always		For other server implementations, the ACL attribute is always
	present for every object. Such servers SHOULD store at least		present for every object. Such servers <bcp14>SHOULD</bcp14> store at least
	the three high-order bits of the mode attribute (MODE4_SUID,		the three high-order bits of the mode attribute (MODE4_SUID,
	MODE4_SGID, MODE4_SVTX). The server SHOULD return a mode		MODE4_SGID, MODE4_SVTX). The server <bcp14>SHOULD</bcp14> return a mod e
	attribute if one is requested, and the low-order nine bits of		attribute if one is requested, and the low-order nine bits of
	the mode (MODE4_R*, MODE4_W*, MODE4_X*) MUST match the result		the mode (MODE4_R*, MODE4_W*, MODE4_X*) <bcp14>MUST</bcp14> match the result
	of applying the method in		of applying the method in
	<xref target="computemode" /> to the ACL attribute.		<xref target="computemode" format="default"/> to the ACL attribute.
	</t>		</t>
	</section>		</section>
	<section title="Creating New Objects" anchor="aclcreate">		<section anchor="aclcreate" numbered="true" toc="default">
	<t>		<name>Creating New Objects</name>
			<t>
	If a server supports any ACL attributes, it may use the ACL		If a server supports any ACL attributes, it may use the ACL
	attributes on the parent directory to compute an initial ACL		attributes on the parent directory to compute an initial ACL
	attribute for a newly created object. This will be referred to		attribute for a newly created object. This will be referred to
	as the inherited ACL within this section. The act of adding		as the inherited ACL within this section. The act of adding
	one or more ACEs to the inherited ACL that are based upon ACEs		one or more ACEs to the inherited ACL that are based upon ACEs
	in the parent directory's ACL will be referred to as		in the parent directory's ACL will be referred to as
	inheriting an ACE within this section.		inheriting an ACE within this section.
	</t>		</t>
	<t>		<t>
	Implementors should standardize what the behavior of CREATE		Implementors should standardize what the behavior of CREATE
	and OPEN must be depending on the presence or absence of the		and OPEN must be depending on the presence or absence of the
	mode and ACL attributes.		mode and ACL attributes.
	<list style="numbers">		</t>
	<t>If just the mode is given in the call:		<ol spacing="normal" type="1">
	<vspace blankLines="1" /> In this case, inheritance		<li>
	SHOULD take place, but the mode MUST be applied to the		<t>If just the mode is given in the call:
	inherited ACL as described in <xref target="setmode"		</t>
	/>, thereby modifying the ACL.		<t> In this case, inheritance
			<bcp14>SHOULD</bcp14> take place, but the mode <bcp14>MUST</bcp14>
			be applied to the
			inherited ACL as described in <xref target="setmode" format="defau
			lt"/>, thereby modifying the ACL.
	</t>		</t>
	<t>If just the ACL is given in the call:		</li>
	<vspace blankLines="1" />		<li>
	In this case, inheritance SHOULD NOT take place, and		<t>If just the ACL is given in the call:
			</t>
			<t>
			In this case, inheritance <bcp14>SHOULD NOT</bcp14> take place, an
			d
	the ACL as defined in the CREATE or OPEN will be set		the ACL as defined in the CREATE or OPEN will be set
	without modification, and the mode modified as in		without modification, and the mode modified as in
	<xref target="settingacl" />.		<xref target="settingacl" format="default"/>.
	</t>		</t>
	<t>If both mode and ACL are given in the call:		</li>
	<vspace blankLines="1" /> In this case, inheritance		<li>
	SHOULD NOT take place, and both attributes will be set		<t>If both mode and ACL are given in the call:
	as described in <xref target="setboth" />.		</t>
			<t> In this case, inheritance
			<bcp14>SHOULD NOT</bcp14> take place, and both attributes will be
			set
			as described in <xref target="setboth" format="default"/>.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	If neither mode nor ACL is given in the call:		If neither mode nor ACL is given in the call:
	<vspace blankLines="1" />		</t>
			<t>
	In the case where an object is being created without		In the case where an object is being created without
	any initial attributes at all, e.g., an OPEN operation		any initial attributes at all, e.g., an OPEN operation
	with an opentype4 of OPEN4_CREATE and a createmode4 of		with an opentype4 of OPEN4_CREATE and a createmode4 of
	EXCLUSIVE4, inheritance SHOULD NOT take place (note that		EXCLUSIVE4, inheritance <bcp14>SHOULD NOT</bcp14> take place (note that
	EXCLUSIVE4_1 is a better choice of createmode4, since it		EXCLUSIVE4_1 is a better choice of createmode4, since it
	does permit initial attributes).		does permit initial attributes).
	Instead, the server SHOULD set permissions to deny all		Instead, the server <bcp14>SHOULD</bcp14> set permissions to deny all
	access to the newly created object. It is expected		access to the newly created object. It is expected
	that the appropriate client will set the desired		that the appropriate client will set the desired
	attributes in a subsequent SETATTR operation, and the		attributes in a subsequent SETATTR operation, and the
	server SHOULD allow that operation to succeed,		server <bcp14>SHOULD</bcp14> allow that operation to succeed,
	regardless of what permissions the object is created		regardless of what permissions the object is created
	with. For example, an empty ACL denies all		with. For example, an empty ACL denies all
	permissions, but the server should allow the owner's		permissions, but the server should allow the owner's
	SETATTR to succeed even though WRITE_ACL is implicitly		SETATTR to succeed even though WRITE_ACL is implicitly
	denied.		denied.
	<vspace blankLines="1" />		</t>
	In other cases, inheritance SHOULD take place, and no		<t>
			In other cases, inheritance <bcp14>SHOULD</bcp14> take place, and
			no
	modifications to the ACL will happen. The mode		modifications to the ACL will happen. The mode
	attribute, if supported, MUST be as computed in		attribute, if supported, <bcp14>MUST</bcp14> be as computed in
	<xref target="computemode" />, with the MODE4_SUID,		<xref target="computemode" format="default"/>, with the MODE4_SUID,
	MODE4_SGID, and MODE4_SVTX bits clear.		MODE4_SGID, and MODE4_SVTX bits clear.
	If no inheritable ACEs exist on the parent directory,		If no inheritable ACEs exist on the parent directory,
	the rules for creating acl, dacl, or sacl attributes		the rules for creating acl, dacl, or sacl attributes
	are implementation defined.		are implementation defined.
	If either the dacl or sacl attribute is supported,		If either the dacl or sacl attribute is supported,
	then the ACL4_DEFAULTED flag SHOULD be set on the		then the ACL4_DEFAULTED flag <bcp14>SHOULD</bcp14> be set on the
	newly created attributes.		newly created attributes.
	<vspace blankLines='1' />		</t>
	</t>		</li>
	</list>		</ol>
	</t>		<section anchor="inheritreq" numbered="true" toc="default">
	<section title="The Inherited ACL" anchor="inheritreq">		<name>The Inherited ACL</name>
	<t>		<t>
	If the object being created is not a directory, the		If the object being created is not a directory, the
	inherited ACL SHOULD NOT inherit ACEs from the parent		inherited ACL <bcp14>SHOULD NOT</bcp14> inherit ACEs from the parent
	directory ACL unless the ACE4_FILE_INHERIT_FLAG is set.		directory ACL unless the ACE4_FILE_INHERIT_FLAG is set.
	</t>		</t>
	<t>		<t>
	If the object being created is a directory, the inherited		If the object being created is a directory, the inherited
	ACL should inherit all inheritable ACEs from the parent		ACL should inherit all inheritable ACEs from the parent
	directory, that is, those that have the ACE4_FILE_INHERIT_ACE or		directory, that is, those that have the ACE4_FILE_INHERIT_ACE or
	ACE4_DIRECTORY_INHERIT_ACE flag set.		ACE4_DIRECTORY_INHERIT_ACE flag set.
	If the inheritable		If the inheritable
	ACE has ACE4_FILE_INHERIT_ACE set but		ACE has ACE4_FILE_INHERIT_ACE set but
	ACE4_DIRECTORY_INHERIT_ACE is clear, the inherited ACE on		ACE4_DIRECTORY_INHERIT_ACE is clear, the inherited ACE on
	the newly created directory MUST have the		the newly created directory <bcp14>MUST</bcp14> have the
	ACE4_INHERIT_ONLY_ACE flag set to prevent the directory		ACE4_INHERIT_ONLY_ACE flag set to prevent the directory
	from being affected by ACEs meant for non-directories.		from being affected by ACEs meant for non-directories.
	</t>		</t>
	<t>		<t>
	When a new directory is created, the server MAY split		When a new directory is created, the server <bcp14>MAY</bcp14> split
	any inherited ACE that is both inheritable and effective		any inherited ACE that is both inheritable and effective
	(in other words, that has neither ACE4_INHERIT_ONLY_ACE		(in other words, that has neither ACE4_INHERIT_ONLY_ACE
	nor ACE4_NO_PROPAGATE_INHERIT_ACE set), into two ACEs,		nor ACE4_NO_PROPAGATE_INHERIT_ACE set), into two ACEs,
	one with no inheritance flags and one with		one with no inheritance flags and one with
	ACE4_INHERIT_ONLY_ACE set. (In the case of a dacl or		ACE4_INHERIT_ONLY_ACE set. (In the case of a dacl or
	sacl attribute, both of those ACEs SHOULD also have the		sacl attribute, both of those ACEs <bcp14>SHOULD</bcp14> also have t he
	ACE4_INHERITED_ACE flag set.) This makes it simpler to		ACE4_INHERITED_ACE flag set.) This makes it simpler to
	modify the effective permissions on the directory		modify the effective permissions on the directory
	without modifying the ACE that is to be inherited to the		without modifying the ACE that is to be inherited to the
	new directory's children.		new directory's children.
	</t>		</t>
	</section>		</section>
			<section anchor="auto_inherit" numbered="true" toc="default">
	<section title="Automatic Inheritance" anchor="auto_inherit">		<name>Automatic Inheritance</name>
	<t>		<t>
	The acl attribute consists only of an array of ACEs, but		The acl attribute consists only of an array of ACEs, but
	the <xref target="attrdef_sacl">sacl</xref>		the <xref target="attrdef_sacl" format="default">sacl</xref>
	and <xref target="attrdef_dacl">dacl</xref> attributes		and <xref target="attrdef_dacl" format="default">dacl</xref> attribu
			tes
	also include an additional flag field.		also include an additional flag field.
	<figure>		</t>
	<artwork>		<sourcecode type="xdr"><![CDATA[
	struct nfsacl41 {		struct nfsacl41 {
	aclflag4 na41_flag;		aclflag4 na41_flag;
	nfsace4 na41_aces&lt;>;		nfsace4 na41_aces<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	The flag field		The flag field
	applies to the entire sacl or dacl; three flag values are		applies to the entire sacl or dacl; three flag values are
	defined:		defined:
	<figure>		</t>
	<artwork>		<sourcecode type="xdr"><![CDATA[
	const ACL4_AUTO_INHERIT = 0x00000001;		const ACL4_AUTO_INHERIT = 0x00000001;
	const ACL4_PROTECTED = 0x00000002;		const ACL4_PROTECTED = 0x00000002;
	const ACL4_DEFAULTED = 0x00000004;		const ACL4_DEFAULTED = 0x00000004;
	</artwork>		]]></sourcecode>
	</figure>		<t>
	and all other bits must be cleared. The		and all other bits must be cleared. The
	ACE4_INHERITED_ACE flag may be set in the ACEs of the sacl		ACE4_INHERITED_ACE flag may be set in the ACEs of the sacl
	or dacl (whereas it must always be cleared in the acl).		or dacl (whereas it must always be cleared in the acl).
	</t>		</t>
	<t>		<t>
	Together these features allow a server to support automatic		Together these features allow a server to support automatic
	inheritance, which we now explain in more detail.		inheritance, which we now explain in more detail.
	</t>		</t>
	<t>		<t>
	Inheritable ACEs are normally inherited by child objects only		Inheritable ACEs are normally inherited by child objects only
	at the time that the child objects are created; later		at the time that the child objects are created; later
	modifications to inheritable ACEs do not result in		modifications to inheritable ACEs do not result in
	modifications to inherited ACEs on descendants.		modifications to inherited ACEs on descendants.
	</t>		</t>
	<t>		<t>
	However, the dacl and sacl provide an OPTIONAL mechanism		However, the dacl and sacl provide an <bcp14>OPTIONAL</bcp14> mechan
			ism
	that allows a client application to propagate changes to		that allows a client application to propagate changes to
	inheritable ACEs to an entire directory hierarchy.		inheritable ACEs to an entire directory hierarchy.
	</t>		</t>
	<t>		<t>
	A server that supports this performs inheritance at object		A server that supports this performs inheritance at object
	creation time in the normal way, and SHOULD set the		creation time in the normal way, and <bcp14>SHOULD</bcp14> set the
	ACE4_INHERITED_ACE flag on any inherited ACEs as they are		ACE4_INHERITED_ACE flag on any inherited ACEs as they are
	added to the new object.		added to the new object.
	</t>		</t>
	<t>		<t>
	A client application such as an ACL editor may then propagate		A client application such as an ACL editor may then propagate
	changes to inheritable ACEs on a directory by recursively		changes to inheritable ACEs on a directory by recursively
	traversing that directory's descendants and modifying each ACL		traversing that directory's descendants and modifying each ACL
	encountered to remove any ACEs with the ACE4_INHERITED_ACE flag		encountered to remove any ACEs with the ACE4_INHERITED_ACE flag
	and to replace them by the new inheritable ACEs (also with the		and to replace them by the new inheritable ACEs (also with the
	ACE4_INHERITED_ACE flag set). It uses the existing ACE		ACE4_INHERITED_ACE flag set). It uses the existing ACE
	inheritance flags in the obvious way to decide which ACEs to		inheritance flags in the obvious way to decide which ACEs to
	propagate. (Note that it may encounter further inheritable		propagate. (Note that it may encounter further inheritable
	ACEs when descending the directory hierarchy and that those		ACEs when descending the directory hierarchy and that those
	will also need to be taken into account when propagating		will also need to be taken into account when propagating
	inheritable ACEs to further descendants.)		inheritable ACEs to further descendants.)
	</t>		</t>
	<t>		<t>
	The reach of this propagation may be limited in two ways:		The reach of this propagation may be limited in two ways:
	first, automatic inheritance is not performed from any		first, automatic inheritance is not performed from any
	directory ACL that has the ACL4_AUTO_INHERIT flag		directory ACL that has the ACL4_AUTO_INHERIT flag
	cleared; and second, automatic inheritance stops wherever		cleared; and second, automatic inheritance stops wherever
	an ACL with the ACL4_PROTECTED flag is set, preventing		an ACL with the ACL4_PROTECTED flag is set, preventing
	modification of that ACL and also (if the ACL is set on		modification of that ACL and also (if the ACL is set on
	a directory) of the ACL on any of the object's descendants.		a directory) of the ACL on any of the object's descendants.
	</t>		</t>
	<t>		<t>
	This propagation is performed independently for the sacl		This propagation is performed independently for the sacl
	and the dacl attributes; thus, the ACL4_AUTO_INHERIT and		and the dacl attributes; thus, the ACL4_AUTO_INHERIT and
	ACL4_PROTECTED flags may be independently set for the sacl		ACL4_PROTECTED flags may be independently set for the sacl
	and the dacl, and propagation of one type of acl may continue		and the dacl, and propagation of one type of acl may continue
	down a hierarchy even where propagation of the other acl has		down a hierarchy even where propagation of the other acl has
	stopped.		stopped.
	</t>		</t>
	<t>		<t>
	New objects should be created with a dacl and a sacl that		New objects should be created with a dacl and a sacl that
	both have the ACL4_PROTECTED flag cleared and the		both have the ACL4_PROTECTED flag cleared and the
	ACL4_AUTO_INHERIT flag set to the same value as that on,		ACL4_AUTO_INHERIT flag set to the same value as that on,
	respectively, the sacl or dacl of the parent object.		respectively, the sacl or dacl of the parent object.
	</t>		</t>
	<t>		<t>
	Both the dacl and sacl attributes are RECOMMENDED, and a server		Both the dacl and sacl attributes are <bcp14>RECOMMENDED</bcp14>, an
			d a server
	may support one without supporting the other.		may support one without supporting the other.
	</t>		</t>
	<t>		<t>
	A server that supports both the old acl attribute and		A server that supports both the old acl attribute and
	one or both of the new dacl or sacl attributes must do so		one or both of the new dacl or sacl attributes must do so
	in such a way as to keep all three attributes consistent		in such a way as to keep all three attributes consistent
	with each other. Thus, the ACEs reported in the acl attribute		with each other. Thus, the ACEs reported in the acl attribute
	should be the union of the ACEs reported in the dacl and		should be the union of the ACEs reported in the dacl and
	sacl attributes, except that the ACE4_INHERITED_ACE flag must		sacl attributes, except that the ACE4_INHERITED_ACE flag must
	be cleared from the ACEs in the acl. And of course a		be cleared from the ACEs in the acl. And of course a
	client that queries only the acl will be unable to determine		client that queries only the acl will be unable to determine
	the values of the sacl or dacl flag fields.		the values of the sacl or dacl flag fields.
	</t>		</t>
	<t>		<t>
	When a client performs a SETATTR for the acl attribute,		When a client performs a SETATTR for the acl attribute,
	the server SHOULD set the ACL4_PROTECTED flag to true on		the server <bcp14>SHOULD</bcp14> set the ACL4_PROTECTED flag to true on
	both the sacl and the dacl. By using the acl attribute,		both the sacl and the dacl. By using the acl attribute,
	as opposed to the dacl or sacl attributes, the client signals		as opposed to the dacl or sacl attributes, the client signals
	that it may not understand automatic inheritance, and thus		that it may not understand automatic inheritance, and thus
	cannot be trusted to set an ACL for which automatic		cannot be trusted to set an ACL for which automatic
	inheritance would make sense.		inheritance would make sense.
	</t>		</t>
	<t>		<t>
	When a client application queries an ACL, modifies it, and sets		When a client application queries an ACL, modifies it, and sets
	it again, it should leave any ACEs marked with		it again, it should leave any ACEs marked with
	ACE4_INHERITED_ACE unchanged, in their original order, at the		ACE4_INHERITED_ACE unchanged, in their original order, at the
	end of the ACL. If the application is unable to do this, it		end of the ACL. If the application is unable to do this, it
	should set the ACL4_PROTECTED flag. This behavior		should set the ACL4_PROTECTED flag. This behavior
	is not enforced by servers, but violations of this rule may		is not enforced by servers, but violations of this rule may
	lead to unexpected results when applications perform automatic		lead to unexpected results when applications perform automatic
	inheritance.		inheritance.
	</t>		</t>
	<t>		<t>
	If a server also supports the mode attribute, it SHOULD set the		If a server also supports the mode attribute, it <bcp14>SHOULD</bcp1
			4> set the
	mode in such a way that leaves inherited ACEs unchanged, in		mode in such a way that leaves inherited ACEs unchanged, in
	their original order, at the end of the ACL. If it is unable		their original order, at the end of the ACL. If it is unable
	to do so, it SHOULD set the ACL4_PROTECTED flag on the file's		to do so, it <bcp14>SHOULD</bcp14> set the ACL4_PROTECTED flag on th e file's
	dacl.		dacl.
	</t>		</t>
	<t>Finally, in the case where the request that creates a new file		<t>Finally, in the case where the request that creates a new file
	or directory does not also set permissions for that file or		or directory does not also set permissions for that file or
	directory, and there are also no ACEs to inherit from the		directory, and there are also no ACEs to inherit from the
	parent's directory, then the server's choice of ACL for the new		parent's directory, then the server's choice of ACL for the new
	object is implementation-dependent. In this case, the server		object is implementation-dependent. In this case, the server
	SHOULD set the ACL4_DEFAULTED flag on the ACL it chooses for		<bcp14>SHOULD</bcp14> set the ACL4_DEFAULTED flag on the ACL it choo ses for
	the new object. An application performing automatic		the new object. An application performing automatic
	inheritance takes the ACL4_DEFAULTED flag as a sign that the		inheritance takes the ACL4_DEFAULTED flag as a sign that the
	ACL should be completely replaced by one generated using the		ACL should be completely replaced by one generated using the
	automatic inheritance rules.		automatic inheritance rules.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		</section>
	</section>		</section>
	</section>		<section anchor="single_server_namespace" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Single-Server Namespace</name>
	$ -->		<t>
	<!-- Copyright (C) The IETF Trust (2007) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="single_server_namespace" title="Single-Server Namespace">
	<t>
	This section describes the NFSv4 single-server namespace.		This section describes the NFSv4 single-server namespace.
	Single-server namespaces may be presented directly to clients,		Single-server namespaces may be presented directly to clients,
	or they may be used as a basis to form larger multi-server		or they may be used as a basis to form larger multi-server
	namespaces (e.g., site-wide or organization-wide) to be presented		namespaces (e.g., site-wide or organization-wide) to be presented
	to clients, as described in <xref target='NEW11' />.		to clients, as described in <xref target="NEW11" format="default"/>.
	</t>		</t>
	<section anchor="server_exports" title="Server Exports">		<section anchor="server_exports" numbered="true" toc="default">
	<t>		<name>Server Exports</name>
			<t>
	On a UNIX server, the namespace describes all the files reachable by		On a UNIX server, the namespace describes all the files reachable by
	pathnames under the root directory or "/". On a Windows server, the		pathnames under the root directory or "/". On a Windows server, the
	namespace constitutes all the files on disks named by mapped disk		namespace constitutes all the files on disks named by mapped disk
	letters. NFS server administrators rarely make the entire server's		letters. NFS server administrators rarely make the entire server's
	file system namespace available to NFS clients. More often, portions		file system namespace available to NFS clients. More often, portions
	of the namespace are made available via an "export" feature. In		of the namespace are made available via an "export" feature. In
	previous versions of the NFS protocol, the root filehandle for each		previous versions of the NFS protocol, the root filehandle for each
	export is obtained through the MOUNT protocol; the client sent a		export is obtained through the MOUNT protocol; the client sent a
	string that identified the export name within the namespace and		string that identified the export name within the namespace and
	the server returned the root filehandle		the server returned the root filehandle
	for that export. The MOUNT protocol also provided an EXPORTS		for that export. The MOUNT protocol also provided an EXPORTS
	procedure that enumerated the server's exports.		procedure that enumerated the server's exports.
	</t>		</t>
	</section>		</section>
	<section anchor="browsing_exports" title="Browsing Exports">		<section anchor="browsing_exports" numbered="true" toc="default">
	<t>		<name>Browsing Exports</name>
			<t>
	The NFSv4.1 protocol provides a root filehandle that clients can		The NFSv4.1 protocol provides a root filehandle that clients can
	use to obtain filehandles for the exports of a particular server,		use to obtain filehandles for the exports of a particular server,
	via a series of LOOKUP operations within a COMPOUND, to traverse		via a series of LOOKUP operations within a COMPOUND, to traverse
	a path. A common user experience is to use a graphical user interface		a path. A common user experience is to use a graphical user interface
	(perhaps a file "Open" dialog window) to find a file via progressive		(perhaps a file "Open" dialog window) to find a file via progressive
	browsing through a directory tree. The client must be able to move		browsing through a directory tree. The client must be able to move
	from one export to another export via single-component, progressive		from one export to another export via single-component, progressive
	LOOKUP operations.		LOOKUP operations.
	</t>		</t>
	<t>		<t>
	This style of browsing is not well supported by the NFSv3 protocol. In NF Sv3, the client expects all		This style of browsing is not well supported by the NFSv3 protocol. In NF Sv3, the client expects all
	LOOKUP operations to remain		LOOKUP operations to remain
	within a single server file system. For example, the device attribute		within a single server file system. For example, the device attribute
	will not change. This prevents a client from taking namespace paths		will not change. This prevents a client from taking namespace paths
	that span exports.		that span exports.
	</t>		</t>
	<t>		<t>
	In the case of NFSv3, an automounter on the client		In the case of NFSv3, an automounter on the client
	can obtain a snapshot of the server's namespace		can obtain a snapshot of the server's namespace
	using the EXPORTS procedure of the MOUNT protocol.		using the EXPORTS procedure of the MOUNT protocol.
	If it understands the server's pathname syntax,		If it understands the server's pathname syntax,
	it can create an image of the server's namespace		it can create an image of the server's namespace
	on the client. The parts of the namespace that		on the client. The parts of the namespace that
	are not exported by the server are filled in		are not exported by the server are filled in
	with directories that might be constructed similarly		with directories that might be constructed similarly
	to an NFSv4.1 "pseudo file system" (see <xref		to an NFSv4.1 "pseudo file system" (see <xref target="server_pseudo_file_s
	target="server_pseudo_file_system" />) that		ystem" format="default"/>) that
	allows the user to browse from one mounted file		allows the user to browse from one mounted file
	system to another. There is a drawback to this		system to another. There is a drawback to this
	representation of the server's namespace on the		representation of the server's namespace on the
	client: it is static. If the server administrator		client: it is static. If the server administrator
	adds a new export, the client will be unaware of it.		adds a new export, the client will be unaware of it.
	</t>		</t>
	</section>		</section>
	<section anchor="server_pseudo_file_system" title="Server Pseudo File System">		<section anchor="server_pseudo_file_system" numbered="true" toc="default">
	<t>		<name>Server Pseudo File System</name>
			<t>
	NFSv4.1 servers avoid this namespace inconsistency by		NFSv4.1 servers avoid this namespace inconsistency by
	presenting all the exports for a given server within the		presenting all the exports for a given server within the
	framework of a single namespace for that server.		framework of a single namespace for that server.
	An NFSv4.1 client uses LOOKUP and READDIR		An NFSv4.1 client uses LOOKUP and READDIR
	operations to browse seamlessly from one export to another.		operations to browse seamlessly from one export to another.
	</t>		</t>
	<t>		<t>
	Where there are portions of the server namespace that are not		Where there are portions of the server namespace that are not
	exported, clients require some way of traversing those portions		exported, clients require some way of traversing those portions
	to reach actual exported file systems. A technique that servers		to reach actual exported file systems. A technique that servers
	may use to provide for this is to bridge the unexported portion of		may use to provide for this is to bridge the unexported portion of
	the namespace via a		the namespace via a
	"pseudo file system" that provides a view of exported directories		"pseudo file system" that provides a view of exported directories
	only. A pseudo file system has a unique fsid and behaves like a		only. A pseudo file system has a unique fsid and behaves like a
	normal, read-only file system.		normal, read-only file system.
	</t>		</t>
	<t>		<t>
	Based on the construction of the server's namespace, it is possible		Based on the construction of the server's namespace, it is possible
	that multiple pseudo file systems may exist. For example,		that multiple pseudo file systems may exist. For example,
	</t>		</t>
	<figure>		<artwork name="" type="" align="left" alt=""><![CDATA[
	<artwork>
	/a pseudo file system		/a pseudo file system
	/a/b real file system		/a/b real file system
	/a/b/c pseudo file system		/a/b/c pseudo file system
	/a/b/c/d real file system		/a/b/c/d real file system
	</artwork>		]]></artwork>
	</figure>		<t>
	<t>
	Each of the pseudo file systems is considered a separate entity and		Each of the pseudo file systems is considered a separate entity and
	therefore MUST have its own fsid, unique among all the fsids for that		therefore <bcp14>MUST</bcp14> have its own fsid, unique among all the fsid s for that
	server.		server.
	</t>		</t>
	</section>		</section>
	<section title="Multiple Roots">		<section numbered="true" toc="default">
	<t>		<name>Multiple Roots</name>
			<t>
	Certain operating environments are sometimes described as		Certain operating environments are sometimes described as
	having "multiple roots". In such environments, individual file		having "multiple roots". In such environments, individual file
	systems are commonly represented by disk or volume names.		systems are commonly represented by disk or volume names.
	NFSv4 servers for these platforms can construct a pseudo file		NFSv4 servers for these platforms can construct a pseudo file
	system above these root names so that disk letters or volume names are		system above these root names so that disk letters or volume names are
	simply directory names in the pseudo root.		simply directory names in the pseudo root.
	</t>		</t>
	</section>		</section>
	<section title="Filehandle Volatility" anchor="pseudo_fs_volatility" >		<section anchor="pseudo_fs_volatility" numbered="true" toc="default">
	<t>		<name>Filehandle Volatility</name>
			<t>
	The nature of the server's pseudo file system is that it is a logical		The nature of the server's pseudo file system is that it is a logical
	representation of file system(s) available from the server.		representation of file system(s) available from the server.
	Therefore, the pseudo file system is most likely constructed		Therefore, the pseudo file system is most likely constructed
	dynamically when the server is first instantiated. It is expected		dynamically when the server is first instantiated. It is expected
	that the pseudo file system may not have an on-disk counterpart from		that the pseudo file system may not have an on-disk counterpart from
	which persistent filehandles could be constructed. Even though it is		which persistent filehandles could be constructed. Even though it is
	preferable that the server provide persistent filehandles for the		preferable that the server provide persistent filehandles for the
	pseudo file system, the NFS client should expect that pseudo file		pseudo file system, the NFS client should expect that pseudo file
	system filehandles are volatile. This can be confirmed by checking		system filehandles are volatile. This can be confirmed by checking
	the associated "fh_expire_type" attribute for those filehandles in		the associated "fh_expire_type" attribute for those filehandles in
	question. If the filehandles are volatile, the NFS client must be		question. If the filehandles are volatile, the NFS client must be
	prepared to recover a filehandle value (e.g., with a series of		prepared to recover a filehandle value (e.g., with a series of
	LOOKUP operations) when receiving an error of NFS4ERR_FHEXPIRED.		LOOKUP operations) when receiving an error of NFS4ERR_FHEXPIRED.
	</t>		</t>
	<t>		<t>
	Because it is quite likely that servers will implement pseudo		Because it is quite likely that servers will implement pseudo
	file systems using volatile filehandles, clients need to be		file systems using volatile filehandles, clients need to be
	prepared for them, rather than assuming that all filehandles		prepared for them, rather than assuming that all filehandles
	will be persistent.		will be persistent.
	</t>		</t>
	</section>		</section>
	<section title="Exported Root">		<section numbered="true" toc="default">
	<t>		<name>Exported Root</name>
			<t>
	If the server's root file system is exported, one might conclude that		If the server's root file system is exported, one might conclude that
	a pseudo file system is unneeded. This is not necessarily so. Assume the		a pseudo file system is unneeded. This is not necessarily so. Assume the
	following file systems on a server:		following file systems on a server:
	</t>		</t>
	<figure>		<artwork name="" type="" align="left" alt=""><![CDATA[
	<artwork>
	/ fs1 (exported)		/ fs1 (exported)
	/a fs2 (not exported)		/a fs2 (not exported)
	/a/b fs3 (exported)		/a/b fs3 (exported)]]></artwork>
	</artwork>		<t>
	</figure>
	<t>
	Because fs2 is not exported, fs3 cannot be reached with simple		Because fs2 is not exported, fs3 cannot be reached with simple
	LOOKUPs. The server must bridge the gap with a pseudo file system.		LOOKUPs. The server must bridge the gap with a pseudo file system.
	</t>		</t>
	</section>		</section>
	<section title="Mount Point Crossing">		<section numbered="true" toc="default">
	<t>		<name>Mount Point Crossing</name>
			<t>
	The server file system environment may be constructed in such a way		The server file system environment may be constructed in such a way
	that one file system contains a directory that is 'covered' or		that one file system contains a directory that is 'covered' or
	mounted upon by a second file system. For example:		mounted upon by a second file system. For example:
	</t>		</t>
	<figure>		<artwork name="" type="" align="left" alt=""><![CDATA[
	<artwork>
	/a/b (file system 1)		/a/b (file system 1)
	/a/b/c/d (file system 2)		/a/b/c/d (file system 2)]]></artwork>
	</artwork>		<t>
	</figure>
	<t>
	The pseudo file system for this server may be constructed to look		The pseudo file system for this server may be constructed to look
	like:		like:
	</t>		</t>
	<figure>		<artwork name="" type="" align="left" alt=""><![CDATA[
	<artwork>
	/ (place holder/not exported)		/ (place holder/not exported)
	/a/b (file system 1)		/a/b (file system 1)
	/a/b/c/d (file system 2)		/a/b/c/d (file system 2)]]></artwork>
	</artwork>		<t>
	</figure>
	<t>
	It is the server's responsibility to present the pseudo file system		It is the server's responsibility to present the pseudo file system
	that is complete to the client. If the client sends a LOOKUP request		that is complete to the client. If the client sends a LOOKUP request
	for the path /a/b/c/d, the server's response is the filehandle of		for the path /a/b/c/d, the server's response is the filehandle of
	the root of the file system /a/b/c/d. In previous versions of the		the root of the file system /a/b/c/d. In previous versions of the
	NFS protocol,		NFS protocol,
	the server would respond with the filehandle of directory		the server would respond with the filehandle of directory
	/a/b/c/d within the file system /a/b.		/a/b/c/d within the file system /a/b.
	</t>		</t>
	<t>		<t>
	The NFS client will be able to determine if it crosses a server mount		The NFS client will be able to determine if it crosses a server mount
	point by a change in the value of the "fsid" attribute.		point by a change in the value of the "fsid" attribute.
	</t>		</t>
	</section>		</section>
	<section title="Security Policy and Namespace Presentation">		<section numbered="true" toc="default">
	<t>		<name>Security Policy and Namespace Presentation</name>
			<t>
	Because NFSv4 clients possess the ability to change the security		Because NFSv4 clients possess the ability to change the security
	mechanisms used, after determining what is allowed,		mechanisms used, after determining what is allowed,
	by using SECINFO and SECINFO_NONAME, the server		by using SECINFO and SECINFO_NONAME, the server
	SHOULD NOT present a different view of the namespace based on		<bcp14>SHOULD NOT</bcp14> present a different view of the namespace based on
	the security mechanism being used by a client. Instead, it		the security mechanism being used by a client. Instead, it
	should present a consistent view and return NFS4ERR_WRONGSEC		should present a consistent view and return NFS4ERR_WRONGSEC
	if an attempt is made to access data with an inappropriate		if an attempt is made to access data with an inappropriate
	security mechanism.		security mechanism.
	</t>		</t>
	<t>		<t>
	If security considerations make it necessary to hide the existence		If security considerations make it necessary to hide the existence
	of a particular file system, as opposed to all of the data within		of a particular file system, as opposed to all of the data within
	it, the server can apply the security policy of		it, the server can apply the security policy of
	a shared resource in the server's namespace to components of the		a shared resource in the server's namespace to components of the
	resource's ancestors. For example:		resource's ancestors. For example:
	</t>		</t>
	<figure>		<artwork name="" type="" align="left" alt=""><![CDATA[
	<artwork>
	/ (place holder/not exported)		/ (place holder/not exported)
	/a/b (file system 1)		/a/b (file system 1)
	/a/b/MySecretProject (file system 2)		/a/b/MySecretProject (file system 2)]]></artwork>
			<t>
	</artwork>
	</figure>
	<t>
	The /a/b/MySecretProject directory is a real file system and		The /a/b/MySecretProject directory is a real file system and
	is the shared resource.		is the shared resource.
	Suppose the security policy for /a/b/MySecretProject is Kerberos		Suppose the security policy for /a/b/MySecretProject is Kerberos
	with integrity and it is desired to limit knowledge of the existence		with integrity and it is desired to limit knowledge of the existence
	of this file system. In this case, the		of this file system. In this case, the
	server should apply the same security policy to /a/b. This allows		server should apply the same security policy to /a/b. This allows
	for knowledge of the existence of a file system to be secured		for knowledge of the existence of a file system to be secured
	when desirable.		when desirable.
	</t>		</t>
	<t>		<t>
	For the case of the use of multiple, disjoint security mechanisms in		For the case of the use of multiple, disjoint security mechanisms in
	the server's resources, applying that sort of policy would result		the server's resources, applying that sort of policy would result
	in the higher-level file system not being accessible using any		in the higher-level file system not being accessible using any
	security flavor.		security flavor.
	Therefore, that sort of configuration is not compatible		Therefore, that sort of configuration is not compatible
	with hiding the existence (as opposed to the contents) from clients		with hiding the existence (as opposed to the contents) from clients
	using multiple disjoint sets of security flavors.		using multiple disjoint sets of security flavors.
	</t>		</t>
	<t>		<t>
	In other circumstances, a desirable policy is for the security of a		In other circumstances, a desirable policy is for the security of a
	particular object in the		particular object in the
	server's namespace to include the union of all security mechanisms of		server's namespace to include the union of all security mechanisms of
	all direct descendants. A common and convenient practice, unless		all direct descendants. A common and convenient practice, unless
	strong security requirements dictate otherwise, is to make the		strong security requirements dictate otherwise, is to make the
	entire the pseudo file system accessible by all of the valid security		entire the pseudo file system accessible by all of the valid security
	mechanisms.		mechanisms.
	</t>		</t>
	<t>		<t>
	Where there is concern about the security of data on the network,		Where there is concern about the security of data on the network,
	clients should use strong security mechanisms to access the pseudo		clients should use strong security mechanisms to access the pseudo
	file system in order to prevent man-in-the-middle attacks.		file system in order to prevent man-in-the-middle attacks.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section numbered="true" toc="default">
	$ -->		<name>State Management</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<t>
	<!-- Copyright (C) The Internet Society (2006) -->
	<section title="State Management" >
	<t>
	Integrating locking into the NFS protocol necessarily causes it to be		Integrating locking into the NFS protocol necessarily causes it to be
	stateful. With the inclusion of such features as share reservations,		stateful. With the inclusion of such features as share reservations,
	file and directory delegations, recallable layouts, and support for		file and directory delegations, recallable layouts, and support for
	mandatory byte-range locking, the protocol becomes substantially more		mandatory byte-range locking, the protocol becomes substantially more
	dependent on proper management of state than the traditional		dependent on proper management of state than the traditional
	combination of NFS and NLM (Network Lock Manager)		combination of NFS and NLM (Network Lock Manager)
	<xref target="xnfs" />. These features include expanded		<xref target="xnfs" format="default"/>. These features include expanded
	locking facilities, which provide some measure of inter-client		locking facilities, which provide some measure of inter-client
	exclusion, but the state also offers		exclusion, but the state also offers
	features not readily providable using a stateless model.		features not readily providable using a stateless model.
	There are three components to		There are three components to
	making this state manageable:		making this state manageable:
	<list style='symbols'>
	<t>
	clear division between client and server
	</t>		</t>
	<t>		<ul spacing="normal">
			<li>
			clear division between client and server
			</li>
			<li>
	ability to reliably detect inconsistency in state between client		ability to reliably detect inconsistency in state between client
	and server		and server
	</t>		</li>
	<t>		<li>
	simple and robust recovery mechanisms		simple and robust recovery mechanisms
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	In this model, the server owns the state information. The client		In this model, the server owns the state information. The client
	requests changes in locks and the server responds with the changes		requests changes in locks and the server responds with the changes
	made. Non-client-initiated changes in locking state are infrequent.		made. Non-client-initiated changes in locking state are infrequent.
	The client receives prompt notification of such changes and can adjust		The client receives prompt notification of such changes and can adjust
	its view of the locking state to reflect the server's changes.		its view of the locking state to reflect the server's changes.
	</t>		</t>
	<t>		<t>
	Individual pieces of state created by the server and passed to the		Individual pieces of state created by the server and passed to the
	client at its request are represented by 128-bit stateids. These		client at its request are represented by 128-bit stateids. These
	stateids may represent a particular open file, a set of		stateids may represent a particular open file, a set of
	byte-range locks held		byte-range locks held
	by a particular owner, or a recallable delegation of privileges		by a particular owner, or a recallable delegation of privileges
	to access a file in particular ways or at a particular location.		to access a file in particular ways or at a particular location.
	</t>		</t>
	<t>		<t>
	In all cases, there is a transition from the most general		In all cases, there is a transition from the most general
	information that represents a client as a whole to the eventual		information that represents a client as a whole to the eventual
	lightweight stateid used for most client and server		lightweight stateid used for most client and server
	locking interactions. The details of this transition will vary		locking interactions. The details of this transition will vary
	with the type of object but it always starts with a client ID.		with the type of object but it always starts with a client ID.
	</t>		</t>
	<section anchor="client_id" title="Client and Session ID" >		<section anchor="client_id" numbered="true" toc="default">
	<t>		<name>Client and Session ID</name>
	A client must establish a client ID (see <xref target="Client_Identifiers"		<t>
	/>)		A client must establish a client ID (see <xref target="Client_Identifiers"
	and then one or more sessionids (see <xref target="Session" />) before		format="default"/>)
			and then one or more sessionids (see <xref target="Session" format="defaul
			t"/>) before
	performing any operations to open, byte-range lock, delegate, or obtain		performing any operations to open, byte-range lock, delegate, or obtain
	a layout for a file object.		a layout for a file object.
	Each session ID is associated with a specific client ID, and thus		Each session ID is associated with a specific client ID, and thus
	serves as a shorthand reference to an NFSv4.1 client.		serves as a shorthand reference to an NFSv4.1 client.
	</t>		</t>
	<t>		<t>
	For some types of locking interactions, the client will represent		For some types of locking interactions, the client will represent
	some number of internal locking entities called "owners", which		some number of internal locking entities called "owners", which
	normally correspond to processes internal to the client. For		normally correspond to processes internal to the client. For
	other types of locking-related objects, such as delegations and		other types of locking-related objects, such as delegations and
	layouts, no such intermediate entities are provided for, and the		layouts, no such intermediate entities are provided for, and the
	locking-related objects are considered to be transferred		locking-related objects are considered to be transferred
	directly between the server and a unitary client.		directly between the server and a unitary client.
	</t>		</t>
	</section> <!-- "Client and Session ID" -->		</section>
	<section anchor="stateid" title="Stateid Definition" >		<section anchor="stateid" numbered="true" toc="default">
	<t>		<name>Stateid Definition</name>
			<t>
	When the server grants a lock of any type (including opens,		When the server grants a lock of any type (including opens,
	byte-range locks, delegations, and layouts), it responds with a		byte-range locks, delegations, and layouts), it responds with a
	unique stateid that represents a set of locks (often a single		unique stateid that represents a set of locks (often a single
	lock) for the same file, of the same type, and sharing the same		lock) for the same file, of the same type, and sharing the same
	ownership characteristics. Thus, opens of the same file by		ownership characteristics. Thus, opens of the same file by
	different open-owners each have an identifying stateid. Similarly,		different open-owners each have an identifying stateid. Similarly,
	each set of byte-range locks on a file owned by a specific lock-owner		each set of byte-range locks on a file owned by a specific lock-owner
	has its own		has its own
	identifying stateid. Delegations and layouts also have		identifying stateid. Delegations and layouts also have
	associated stateids by which they may be referenced.		associated stateids by which they may be referenced.
	The stateid is used as a shorthand reference to a lock or set		The stateid is used as a shorthand reference to a lock or set
	of locks, and given a stateid, the server can determine the associated		of locks, and given a stateid, the server can determine the associated
	state-owner or state-owners (in the case of an open-owner/lock-owner pai r)		state-owner or state-owners (in the case of an open-owner/lock-owner pai r)
	and the associated filehandle. When stateids are used, the current		and the associated filehandle. When stateids are used, the current
	filehandle must be the one associated with that stateid.		filehandle must be the one associated with that stateid.
	</t>		</t>
	<t>		<t>
	All stateids associated with a given client ID are associated with		All stateids associated with a given client ID are associated with
	a common lease that represents the claim of those stateids		a common lease that represents the claim of those stateids
	and the objects they represent to be maintained		and the objects they represent to be maintained
	by the server. See <xref target="lease_renewal" /> for a		by the server. See <xref target="lease_renewal" format="default"/> for a
	discussion of the lease.		discussion of the lease.
	</t>		</t>
	<t>		<t>
	The server may assign stateids independently for different clients.		The server may assign stateids independently for different clients.
	A stateid with the same bit pattern for one client may designate		A stateid with the same bit pattern for one client may designate
	an entirely different set of locks for a different client. The		an entirely different set of locks for a different client. The
	stateid is always interpreted with respect to the client ID associated		stateid is always interpreted with respect to the client ID associated
	with the current session. Stateids apply to all sessions associated		with the current session. Stateids apply to all sessions associated
	with the given client ID, and the client may use a stateid obtained from		with the given client ID, and the client may use a stateid obtained from
	one session on another session associated with the same client ID.		one session on another session associated with the same client ID.
	</t>		</t>
	<section anchor="stateid_types" title="Stateid Types">		<section anchor="stateid_types" numbered="true" toc="default">
	<t>		<name>Stateid Types</name>
	With the exception of special stateids (see <xref target="special_stat		<t>
	eid"/>),		With the exception of special stateids (see <xref target="special_stat
			eid" format="default"/>),
	each stateid		each stateid
	represents locking objects of one of a set of types defined		represents locking objects of one of a set of types defined
	by the NFSv4.1 protocol. Note that in all these cases, where		by the NFSv4.1 protocol. Note that in all these cases, where
	we speak of guarantee, it is understood there are		we speak of guarantee, it is understood there are
	situations such as a client restart, or lock revocation,		situations such as a client restart, or lock revocation,
	that allow the guarantee to be voided.		that allow the guarantee to be voided.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	Stateids may represent opens of files.		Stateids may represent opens of files.
	<vspace blankLines="1" />		</t>
			<t>
	Each stateid in this case represents the OPEN state for a		Each stateid in this case represents the OPEN state for a
	given client ID/open-owner/filehandle triple. Such		given client ID/open-owner/filehandle triple. Such
	stateids are subject to change (with consequent		stateids are subject to change (with consequent
	incrementing of the stateid's seqid) in response to OPENs that		incrementing of the stateid's seqid) in response to OPENs that
	result in upgrade and OPEN_DOWNGRADE operations.		result in upgrade and OPEN_DOWNGRADE operations.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	Stateids may represent sets of byte-range locks.		Stateids may represent sets of byte-range locks.
	<vspace blankLines="1" />		</t>
			<t>
	All locks held on a particular file by a particular owner and		All locks held on a particular file by a particular owner and
	gotten under the aegis of a particular open file		gotten under the aegis of a particular open file
	are associated with a single stateid with the seqid		are associated with a single stateid with the seqid
	being incremented whenever LOCK and LOCKU operations affect that		being incremented whenever LOCK and LOCKU operations affect that
	set of locks.		set of locks.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	Stateids may represent file delegations, which are		Stateids may represent file delegations, which are
	recallable guarantees by the server to the client		recallable guarantees by the server to the client
	that other clients will not reference or		that other clients will not reference or
	modify a particular file, until the delegation		modify a particular file, until the delegation
	is returned. In NFSv4.1, file delegations may be		is returned. In NFSv4.1, file delegations may be
	obtained on both regular and non-regular files.		obtained on both regular and non-regular files.
	<vspace blankLines="1" />		</t>
			<t>
	A stateid represents a single delegation held by		A stateid represents a single delegation held by
	a client for a particular filehandle.		a client for a particular filehandle.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	Stateids may represent directory delegations, which		Stateids may represent directory delegations, which
	are recallable guarantees by the server to the client		are recallable guarantees by the server to the client
	that other clients will not modify the directory,		that other clients will not modify the directory,
	until the delegation is returned.		until the delegation is returned.
	<vspace blankLines="1" />		</t>
			<t>
	A stateid represents a single delegation held by		A stateid represents a single delegation held by
	a client for a particular directory filehandle.		a client for a particular directory filehandle.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	Stateids may represent layouts, which are recallable		Stateids may represent layouts, which are recallable
	guarantees by the server to the client that particular		guarantees by the server to the client that particular
	files may be accessed via an alternate data access		files may be accessed via an alternate data access
	protocol at specific locations. Such access is		protocol at specific locations. Such access is
	limited to particular sets of byte-ranges and may		limited to particular sets of byte-ranges and may
	proceed until those byte-ranges are reduced or the		proceed until those byte-ranges are reduced or the
	layout is returned.		layout is returned.
	<vspace blankLines="1" />		</t>
			<t>
	A stateid represents the set of all layouts held by a particular		A stateid represents the set of all layouts held by a particular
	client for a particular filehandle with a given		client for a particular filehandle with a given
	layout type. The seqid is updated as the layouts		layout type. The seqid is updated as the layouts
	of that set of byte-ranges change, via layout stateid changing ope rations such		of that set of byte-ranges change, via layout stateid changing ope rations such
	as LAYOUTGET and LAYOUTRETURN.		as LAYOUTGET and LAYOUTRETURN.
	</t>		</t>
	</list>		</li>
	</t>		</ul>
	</section>		</section>
	<section anchor="stateid_structure" title="Stateid Structure">		<section anchor="stateid_structure" numbered="true" toc="default">
	<t>		<name>Stateid Structure</name>
			<t>
	Stateids are divided into two fields, a 96-bit		Stateids are divided into two fields, a 96-bit
	"other" field identifying the specific set		"other" field identifying the specific set
	of locks and a 32-bit "seqid" sequence value.		of locks and a 32-bit "seqid" sequence value.
	Except in the case of special stateids		Except in the case of special stateids
	(see <xref target="special_stateid"/>),		(see <xref target="special_stateid" format="default"/>),
	a particular value of the		a particular value of the
	"other" field denotes a		"other" field denotes a
	set of locks of the same type (for example,		set of locks of the same type (for example,
	byte-range locks, opens, delegations, or layouts),		byte-range locks, opens, delegations, or layouts),
	for a specific file or directory, and sharing		for a specific file or directory, and sharing
	the same ownership characteristics. The seqid		the same ownership characteristics. The seqid
	designates a specific instance of such a set of		designates a specific instance of such a set of
	locks, and is incremented to indicate changes in		locks, and is incremented to indicate changes in
	such a set of locks, either by the addition or		such a set of locks, either by the addition or
	deletion of locks from the set, a change in the		deletion of locks from the set, a change in the
	byte-range they apply to, or an upgrade or downgrade		byte-range they apply to, or an upgrade or downgrade
	in the type of one or more locks.		in the type of one or more locks.
	</t>		</t>
	<t>		<t>
	When such a set of locks is first created, the server returns a		When such a set of locks is first created, the server returns a
	stateid with seqid value of one. On subsequent		stateid with seqid value of one. On subsequent
	operations that modify the set of locks, the server		operations that modify the set of locks, the server
	is required to increment the "seqid" field by one		is required to increment the "seqid" field by one
	whenever it returns a stateid for the same		whenever it returns a stateid for the same
	state-owner/file/type combination and there is some		state-owner/file/type combination and there is some
	change in the set of locks actually designated.		change in the set of locks actually designated.
	In this case, the server will return a stateid with an "other" field		In this case, the server will return a stateid with an "other" field
	the same as previously used for that		the same as previously used for that
	state-owner/file/type combination, with an		state-owner/file/type combination, with an
	incremented "seqid" field.		incremented "seqid" field.
	This pattern continues until the seqid is incremented		This pattern continues until the seqid is incremented
	past NFS4_UINT32_MAX, and one		past NFS4_UINT32_MAX, and one
	(not zero) is the next seqid value.		(not zero) is the next seqid value.
	</t>		</t>
	<t>		<t>
	The purpose of the incrementing of the seqid		The purpose of the incrementing of the seqid
	is to allow the server to		is to allow the server to
	communicate to the client the order in which		communicate to the client the order in which
	operations that modified locking state associated		operations that modified locking state associated
	with a stateid have been processed and to make		with a stateid have been processed and to make
	it possible for the client to send requests		it possible for the client to send requests
	that are conditional on the set of locks not		that are conditional on the set of locks not
	having changed since the stateid in question		having changed since the stateid in question
	was returned.		was returned.
	</t>		</t>
	<t>		<t>
	Except for layout stateids (<xref target="layout_stateid"/>),		Except for layout stateids (<xref target="layout_stateid" format="defau
			lt"/>),
	when a client sends a stateid to the server, it has two		when a client sends a stateid to the server, it has two
	choices with regard to the seqid sent. It may set the seqid		choices with regard to the seqid sent. It may set the seqid
	to zero to indicate to the server that it wishes the most		to zero to indicate to the server that it wishes the most
	up-to-date seqid for that stateid's "other" field to be		up-to-date seqid for that stateid's "other" field to be
	used. This would be the common choice in the case of a		used. This would be the common choice in the case of a
	stateid sent with a READ or WRITE operation. It also may		stateid sent with a READ or WRITE operation. It also may
	set a non-zero value, in which case the server checks if that		set a non-zero value, in which case the server checks if that
	seqid is the correct one. In that case, the server is		seqid is the correct one. In that case, the server is
	required to return NFS4ERR_OLD_STATEID if the seqid is lower		required to return NFS4ERR_OLD_STATEID if the seqid is lower
	than the most current value and NFS4ERR_BAD_STATEID if the		than the most current value and NFS4ERR_BAD_STATEID if the
	seqid is greater than the most current value. This would be		seqid is greater than the most current value. This would be
	the common choice in the case of stateids sent with a CLOSE		the common choice in the case of stateids sent with a CLOSE
	or OPEN_DOWNGRADE. Because OPENs may be sent in parallel		or OPEN_DOWNGRADE. Because OPENs may be sent in parallel
	for the same owner, a client might close a file without		for the same owner, a client might close a file without
	knowing that an OPEN upgrade had been done by the server,		knowing that an OPEN upgrade had been done by the server,
	changing the lock in question. If CLOSE were sent with a		changing the lock in question. If CLOSE were sent with a
	zero seqid, the OPEN upgrade would be cancelled before the		zero seqid, the OPEN upgrade would be cancelled before the
	client even received an indication that an upgrade had		client even received an indication that an upgrade had
	happened.		happened.
	</t>		</t>
	<t>		<t>
	When a stateid is sent by the server to the client as part of		When a stateid is sent by the server to the client as part of
	a callback operation, it is not subject to checking for		a callback operation, it is not subject to checking for
	a current seqid and returning NFS4ERR_OLD_STATEID. This		a current seqid and returning NFS4ERR_OLD_STATEID. This
	is because the client is not in a position to know the		is because the client is not in a position to know the
	most up-to-date seqid and thus cannot verify it. Unless		most up-to-date seqid and thus cannot verify it. Unless
	specially noted, the seqid value for a stateid sent by the		specially noted, the seqid value for a stateid sent by the
	server to the client as part of a callback is required		server to the client as part of a callback is required
	to be zero with NFS4ERR_BAD_STATEID returned if it is		to be zero with NFS4ERR_BAD_STATEID returned if it is
	not.		not.
	</t>		</t>
	<t>		<t>
	In making comparisons between seqids, both by the client		In making comparisons between seqids, both by the client
	in determining the order of operations and by the server		in determining the order of operations and by the server
	in determining whether the NFS4ERR_OLD_STATEID is to be		in determining whether the NFS4ERR_OLD_STATEID is to be
	returned, the possibility of the seqid being swapped		returned, the possibility of the seqid being swapped
	around past the NFS4_UINT32_MAX value needs to be taken		around past the NFS4_UINT32_MAX value needs to be taken
	into account. When two seqid values are being compared,		into account. When two seqid values are being compared,
	the total count of slots for all sessions associated		the total count of slots for all sessions associated
	with the current client is used to do this. When one		with the current client is used to do this. When one
	seqid value is less than this total slot count and		seqid value is less than this total slot count and
	another seqid value is greater than NFS4_UINT32_MAX		another seqid value is greater than NFS4_UINT32_MAX
	minus the total slot count, the former is to be treated		minus the total slot count, the former is to be treated
	as lower than the latter, despite the fact that it is		as lower than the latter, despite the fact that it is
	numerically greater.		numerically greater.
	</t>		</t>
			</section>
	</section> <!-- "Stateid Structure" -->		<section anchor="special_stateid" numbered="true" toc="default">
	<section anchor="special_stateid" title="Special Stateids">		<name>Special Stateids</name>
	<t>		<t>
	Stateid values whose "other" field is either all zeros or all		Stateid values whose "other" field is either all zeros or all
	ones are reserved. They may not be assigned by the server but		ones are reserved. They may not be assigned by the server but
	have special meanings defined by the protocol. The particular		have special meanings defined by the protocol. The particular
	meaning depends on whether the "other" field is all zeros or		meaning depends on whether the "other" field is all zeros or
	all ones and the specific value of the "seqid" field.		all ones and the specific value of the "seqid" field.
	</t>		</t>
	<t>		<t>
	The following combinations of "other" and "seqid" are defined		The following combinations of "other" and "seqid" are defined
	in NFSv4.1:		in NFSv4.1:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	When "other" and "seqid" are both zero, the		When "other" and "seqid" are both zero, the
	stateid is treated as a special anonymous		stateid is treated as a special anonymous
	stateid, which can be used in READ, WRITE,		stateid, which can be used in READ, WRITE,
	and SETATTR requests to indicate the absence		and SETATTR requests to indicate the absence
	of any OPEN state associated with the		of any OPEN state associated with the
	request. When an anonymous stateid value is		request. When an anonymous stateid value is
	used and an existing open denies the form of		used and an existing open denies the form of
	access requested, then access will be denied		access requested, then access will be denied
	to the request. This stateid MUST NOT be		to the request. This stateid <bcp14>MUST NOT</bcp14> be
	used on operations to data servers (<xref		used on operations to data servers (<xref target="ds_ops" format="
	target="ds_ops" />).		default"/>).
	</t>		</li>
	<t>		<li>
	When "other" and "seqid" are both all ones,		When "other" and "seqid" are both all ones,
	the stateid is a special READ bypass stateid.		the stateid is a special READ bypass stateid.
	When this value is used in WRITE or SETATTR,		When this value is used in WRITE or SETATTR,
	it is treated like the anonymous value.		it is treated like the anonymous value.
	When used in READ, the server MAY grant		When used in READ, the server <bcp14>MAY</bcp14> grant
	access, even if access would normally be		access, even if access would normally be
	denied to READ operations. This stateid MUST		denied to READ operations. This stateid <bcp14>MUST
	NOT be used on operations to data servers.		NOT</bcp14> be used on operations to data servers.
	</t>		</li>
	<t>		<li>
	When "other" is zero and "seqid" is one,		When "other" is zero and "seqid" is one,
	the stateid represents the current stateid,		the stateid represents the current stateid,
	which is whatever value is the last stateid		which is whatever value is the last stateid
	returned by an operation within the COMPOUND.		returned by an operation within the COMPOUND.
	In the case of an OPEN, the stateid returned		In the case of an OPEN, the stateid returned
	for the open file and not the delegation is		for the open file and not the delegation is
	used. The stateid passed to the operation in		used. The stateid passed to the operation in
	place of the special value has its "seqid"		place of the special value has its "seqid"
	value set to zero, except when the current		value set to zero, except when the current
	stateid is used by the operation CLOSE or		stateid is used by the operation CLOSE or
	OPEN_DOWNGRADE. If there is no operation		OPEN_DOWNGRADE. If there is no operation
	in the COMPOUND that has returned a stateid		in the COMPOUND that has returned a stateid
	value, the server MUST return the error		value, the server <bcp14>MUST</bcp14> return the error
	NFS4ERR_BAD_STATEID. As illustrated in <xref		NFS4ERR_BAD_STATEID. As illustrated in <xref target="csid_example4
	target="csid_example4"/>, if the value of a		" format="default"/>, if the value of a
	current stateid is a special stateid and the		current stateid is a special stateid and the
	stateid of an operation's arguments has		stateid of an operation's arguments has
	"other" set to zero and "seqid" set to one,		"other" set to zero and "seqid" set to one,
	then the server MUST return the error		then the server <bcp14>MUST</bcp14> return the error
	NFS4ERR_BAD_STATEID.		NFS4ERR_BAD_STATEID.
	</t>		</li>
	<t>		<li>
	When "other" is zero and "seqid" is NFS4_UINT32_MAX,		When "other" is zero and "seqid" is NFS4_UINT32_MAX,
	the stateid represents a reserved stateid		the stateid represents a reserved stateid
	value defined to be invalid. When this		value defined to be invalid. When this
	stateid is used, the server MUST return the error		stateid is used, the server <bcp14>MUST</bcp14> return the error
	NFS4ERR_BAD_STATEID.		NFS4ERR_BAD_STATEID.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	If a stateid value is used that has all zeros or all ones in the		If a stateid value is used that has all zeros or all ones in the
	"other" field but does not match one of the cases above, the server		"other" field but does not match one of the cases above, the server
	MUST return the error NFS4ERR_BAD_STATEID.		<bcp14>MUST</bcp14> return the error NFS4ERR_BAD_STATEID.
	</t>		</t>
	<t>		<t>
	Special stateids, unlike other stateids, are not associated with		Special stateids, unlike other stateids, are not associated with
	individual client IDs or filehandles and can be used with all valid		individual client IDs or filehandles and can be used with all valid
	client IDs and filehandles. In the case of a special		client IDs and filehandles. In the case of a special
	stateid designating the current stateid, the current stateid		stateid designating the current stateid, the current stateid
	value substituted for the special stateid is associated with a		value substituted for the special stateid is associated with a
	particular client ID and filehandle, and so, if it is used		particular client ID and filehandle, and so, if it is used
	where the current filehandle does not match that associated with the c urrent		where the current filehandle does not match that associated with the c urrent
	stateid, the operation to which the stateid is passed will return		stateid, the operation to which the stateid is passed will return
	NFS4ERR_BAD_STATEID.		NFS4ERR_BAD_STATEID.
	</t>		</t>
	</section> <!-- "Special Stateids" -->		</section>
	<section anchor="stateid_lifetime" title="Stateid Lifetime and Validation"		<section anchor="stateid_lifetime" numbered="true" toc="default">
	>		<name>Stateid Lifetime and Validation</name>
	<t>		<t>
	Stateids must remain valid until either a client restart or a		Stateids must remain valid until either a client restart or a
	server restart or until the client returns all of the locks		server restart or until the client returns all of the locks
	associated with the stateid by means of an operation such as		associated with the stateid by means of an operation such as
	CLOSE or DELEGRETURN.		CLOSE or DELEGRETURN.
	If the locks are lost due to revocation, as long		If the locks are lost due to revocation, as long
	as the client ID is valid, the stateid remains		as the client ID is valid, the stateid remains
	a valid designation of that revoked state until		a valid designation of that revoked state until
	the client frees it by using FREE_STATEID.		the client frees it by using FREE_STATEID.
	Stateids associated		Stateids associated
	with byte-range locks are an exception. They remain valid even		with byte-range locks are an exception. They remain valid even
	if a LOCKU frees all remaining locks, so long as the open file		if a LOCKU frees all remaining locks, so long as the open file
	with which they are associated remains open, unless the client		with which they are associated remains open, unless the client
	frees the stateids via the FREE_STATEID operation.		frees the stateids via the FREE_STATEID operation.
	</t>		</t>
	<t>		<t>
	It should be noted that there are situations in which the		It should be noted that there are situations in which the
	client's locks become invalid, without the client requesting		client's locks become invalid, without the client requesting
	they be returned. These include lease expiration and a number		they be returned. These include lease expiration and a number
	of forms of lock revocation within the lease period. It is		of forms of lock revocation within the lease period. It is
	important to note that in these situations, the stateid remains		important to note that in these situations, the stateid remains
	valid and the client can use it to determine the disposition of		valid and the client can use it to determine the disposition of
	the associated lost locks.		the associated lost locks.
	</t>		</t>
	<t>		<t>
	An "other" value must never be reused for a different purpose		An "other" value must never be reused for a different purpose
	(i.e., different filehandle, owner, or type of locks) within the		(i.e., different filehandle, owner, or type of locks) within the
	context of a single client ID. A server may retain the "other"		context of a single client ID. A server may retain the "other"
	value for the same purpose beyond the point where it may otherwise		value for the same purpose beyond the point where it may otherwise
	be freed, but if it does so, it must maintain "seqid" continuity		be freed, but if it does so, it must maintain "seqid" continuity
	with previous values.		with previous values.
	</t>		</t>
	<t>		<t>
	One mechanism that may be used to satisfy the requirement that the		One mechanism that may be used to satisfy the requirement that the
	server recognize invalid and out-of-date stateids is for		server recognize invalid and out-of-date stateids is for
	the server to divide the "other" field of the stateid into two		the server to divide the "other" field of the stateid into two
	fields.		fields.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	an index into a table of locking-state structures.		an index into a table of locking-state structures.
	</t>		</li>
	<t>		<li>
	a generation number that is incremented on each allocation		a generation number that is incremented on each allocation
	of a table entry for a particular use.		of a table entry for a particular use.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	And then store in each table entry,		And then store in each table entry,
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	the client ID with which the stateid is associated.		the client ID with which the stateid is associated.
	</t>		</li>
	<t>		<li>
	the current generation number for the (at most one)		the current generation number for the (at most one)
	valid stateid sharing this index value.		valid stateid sharing this index value.
	</t>		</li>
	<t>		<li>
	the filehandle of the file on which the locks are taken.		the filehandle of the file on which the locks are taken.
	</t>		</li>
	<t>		<li>
	an indication of the type of stateid (open, byte-range lock,		an indication of the type of stateid (open, byte-range lock,
	file delegation, directory delegation, layout).		file delegation, directory delegation, layout).
	</t>		</li>
	<t>		<li>
	the last "seqid" value returned corresponding to the current		the last "seqid" value returned corresponding to the current
	"other" value.		"other" value.
	</t>		</li>
	<t>		<li>
	an indication of the current status of the locks		an indication of the current status of the locks
	associated with this stateid, in particular,		associated with this stateid, in particular,
	whether these have been revoked and if so, for what reason.		whether these have been revoked and if so, for what reason.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	With this information, an incoming stateid can be validated and		With this information, an incoming stateid can be validated and
	the appropriate error returned when necessary. Special and		the appropriate error returned when necessary. Special and
	non-special stateids are handled separately. (See		non-special stateids are handled separately. (See
	<xref target='special_stateid' /> for a discussion of special		<xref target="special_stateid" format="default"/> for a discussion of special
	stateids.)		stateids.)
	</t>		</t>
	<t>		<t>
	Note that stateids are implicitly qualified by the current client		Note that stateids are implicitly qualified by the current client
	ID, as derived from the client ID associated with the current		ID, as derived from the client ID associated with the current
	session. Note, however, that the semantics of the session will		session. Note, however, that the semantics of the session will
	prevent stateids associated with a previous client or server		prevent stateids associated with a previous client or server
	instance from being analyzed by this procedure.		instance from being analyzed by this procedure.
	</t>		</t>
	<t>		<t>
	If server restart has resulted in an invalid		If server restart has resulted in an invalid
	client ID or a session ID that is invalid, SEQUENCE will return		client ID or a session ID that is invalid, SEQUENCE will return
	an error and the operation that takes a stateid as an argument will ne ver		an error and the operation that takes a stateid as an argument will ne ver
	be processed.		be processed.
	</t>		</t>
	<t>		<t>
	If there has been a server restart where there is a persistent		If there has been a server restart where there is a persistent
	session and all leased state has been lost, then the session		session and all leased state has been lost, then the session
	in question will, although valid, be marked as dead, and any		in question will, although valid, be marked as dead, and any
	operation not satisfied by means of the reply cache will		operation not satisfied by means of the reply cache will
	receive the error NFS4ERR_DEADSESSION, and thus not be		receive the error NFS4ERR_DEADSESSION, and thus not be
	processed as indicated below.		processed as indicated below.
	</t>		</t>
	<t>		<t>
	When a stateid is being tested and the "other" field is all		When a stateid is being tested and the "other" field is all
	zeros or all ones, a check that		zeros or all ones, a check that
	the "other" and "seqid" fields match a defined combination for		the "other" and "seqid" fields match a defined combination for
	a special stateid is done and the results determined as follows:		a special stateid is done and the results determined as follows:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	If the "other" and "seqid" fields do not match a defined		If the "other" and "seqid" fields do not match a defined
	combination associated with a special stateid, the error		combination associated with a special stateid, the error
	NFS4ERR_BAD_STATEID is returned.		NFS4ERR_BAD_STATEID is returned.
	</t>		</li>
	<t>		<li>
	If the special stateid is one designating the current		If the special stateid is one designating the current
	stateid and there is a current stateid, then the current		stateid and there is a current stateid, then the current
	stateid is substituted for the special stateid and the		stateid is substituted for the special stateid and the
	checks appropriate to non-special stateids are performed.		checks appropriate to non-special stateids are performed.
	</t>		</li>
	<t>		<li>
	If the combination is valid in general but is not		If the combination is valid in general but is not
	appropriate to the context in which the stateid is used		appropriate to the context in which the stateid is used
	(e.g., an all-zero stateid is used when an OPEN stateid		(e.g., an all-zero stateid is used when an OPEN stateid
	is required in a LOCK operation), the error		is required in a LOCK operation), the error
	NFS4ERR_BAD_STATEID is also returned.		NFS4ERR_BAD_STATEID is also returned.
	</t>		</li>
	<t>		<li>
	Otherwise, the check is completed and the special stateid		Otherwise, the check is completed and the special stateid
	is accepted as valid.		is accepted as valid.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	When a stateid is being tested,		When a stateid is being tested,
	and the "other" field is neither all zeros nor all ones, the		and the "other" field is neither all zeros nor all ones, the
	following procedure could be used to		following procedure could be used to
	validate an incoming stateid and return an appropriate error,		validate an incoming stateid and return an appropriate error,
	when necessary, assuming that the "other" field would be divided		when necessary, assuming that the "other" field would be divided
	into a table index and an entry generation.		into a table index and an entry generation.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	If the table index field is outside the range of the		If the table index field is outside the range of the
	associated table, return NFS4ERR_BAD_STATEID.		associated table, return NFS4ERR_BAD_STATEID.
	</t>		</li>
	<t>		<li>
	If the selected table entry is of a different generation than		If the selected table entry is of a different generation than
	that specified in the incoming stateid, return		that specified in the incoming stateid, return
	NFS4ERR_BAD_STATEID.		NFS4ERR_BAD_STATEID.
	</t>		</li>
	<t>		<li>
	If the selected table entry does not match the current		If the selected table entry does not match the current
	filehandle, return NFS4ERR_BAD_STATEID.		filehandle, return NFS4ERR_BAD_STATEID.
	</t>		</li>
	<t>		<li>
	If the client ID in the table entry does not match the		If the client ID in the table entry does not match the
	client ID associated with the current session,		client ID associated with the current session,
	return NFS4ERR_BAD_STATEID.		return NFS4ERR_BAD_STATEID.
	</t>		</li>
	<t>		<li>
	If the stateid represents revoked state, then return		If the stateid represents revoked state, then return
	NFS4ERR_EXPIRED, NFS4ERR_ADMIN_REVOKED, or		NFS4ERR_EXPIRED, NFS4ERR_ADMIN_REVOKED, or
	NFS4ERR_DELEG_REVOKED, as appropriate.		NFS4ERR_DELEG_REVOKED, as appropriate.
	</t>		</li>
	<t>		<li>
	If the stateid type is not valid for the context in which the		If the stateid type is not valid for the context in which the
	stateid appears, return NFS4ERR_BAD_STATEID.		stateid appears, return NFS4ERR_BAD_STATEID.
	Note that a stateid may be valid in general, as would be		Note that a stateid may be valid in general, as would be
	reported by the TEST_STATEID operation, but be invalid for		reported by the TEST_STATEID operation, but be invalid for
	a particular operation, as, for example, when a stateid		a particular operation, as, for example, when a stateid
	that doesn't represent byte-range locks is passed to		that doesn't represent byte-range locks is passed to
	the non-from_open case of LOCK or to LOCKU, or when a stateid		the non-from_open case of LOCK or to LOCKU, or when a stateid
	that does not represent an open is passed to CLOSE or		that does not represent an open is passed to CLOSE or
	OPEN_DOWNGRADE. In such cases, the server MUST return		OPEN_DOWNGRADE. In such cases, the server <bcp14>MUST</bcp14> ret urn
	NFS4ERR_BAD_STATEID.		NFS4ERR_BAD_STATEID.
	</t>		</li>
	<t>		<li>
	If the "seqid" field is not zero and it is greater		If the "seqid" field is not zero and it is greater
	than the current sequence value corresponding to the		than the current sequence value corresponding to the
	current "other" field, return NFS4ERR_BAD_STATEID.		current "other" field, return NFS4ERR_BAD_STATEID.
	</t>		</li>
	<t>		<li>
	If the "seqid" field is not zero and it is less		If the "seqid" field is not zero and it is less
	than the current sequence value corresponding to the		than the current sequence value corresponding to the
	current "other" field, return NFS4ERR_OLD_STATEID.		current "other" field, return NFS4ERR_OLD_STATEID.
	</t>		</li>
	<t>		<li>
	Otherwise, the stateid is valid and the table entry		Otherwise, the stateid is valid and the table entry
	should contain any additional information about the		should contain any additional information about the
	type of stateid and information associated with that		type of stateid and information associated with that
	particular type of stateid, such as the associated		particular type of stateid, such as the associated
	set of locks, e.g., open-owner and		set of locks, e.g., open-owner and
	lock-owner information, as well as information on the		lock-owner information, as well as information on the
	specific locks, e.g., open modes and byte-ranges.		specific locks, e.g., open modes and byte-ranges.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section> <!-- "Stateid Lifetime and Validation" -->		<section anchor="stateid_use" numbered="true" toc="default">
	<section anchor="stateid_use" title="Stateid Use for I/O Operations">		<name>Stateid Use for I/O Operations</name>
	<t>		<t>
	Clients performing I/O operations need to select an		Clients performing I/O operations need to select an
	appropriate stateid based on the		appropriate stateid based on the
	locks (including opens and delegations) held by the client and		locks (including opens and delegations) held by the client and
	the various types of state-owners sending the I/O requests.		the various types of state-owners sending the I/O requests.
	SETATTR operations that change the file size are treated		SETATTR operations that change the file size are treated
	like I/O operations in this regard.		like I/O operations in this regard.
	</t>		</t>
	<t>		<t>
	The following rules, applied in order of decreasing priority,		The following rules, applied in order of decreasing priority,
	govern the selection of the appropriate stateid. In following		govern the selection of the appropriate stateid. In following
	these rules, the client will only consider locks of which it		these rules, the client will only consider locks of which it
	has actually received notification by an appropriate operation		has actually received notification by an appropriate operation
	response or callback. Note that the		response or callback. Note that the
	rules are slightly different in the case of I/O to data servers		rules are slightly different in the case of I/O to data servers
	when file layouts are being		when file layouts are being
	used (see <xref target="global_stateid" />).		used (see <xref target="global_stateid" format="default"/>).
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	If the client holds a delegation for the file in question, the		If the client holds a delegation for the file in question, the
	delegation stateid SHOULD be used.		delegation stateid <bcp14>SHOULD</bcp14> be used.
	</t>		</li>
	<t>		<li>
	Otherwise, if the entity corresponding to the lock-owner (e.g., a process)		Otherwise, if the entity corresponding to the lock-owner (e.g., a process)
	sending the I/O has a byte-range lock stateid for the associated o pen file,		sending the I/O has a byte-range lock stateid for the associated o pen file,
	then the byte-range lock stateid for that lock-owner and open file SHOULD		then the byte-range lock stateid for that lock-owner and open file <bcp14>SHOULD</bcp14>
	be used.		be used.
	</t>		</li>
	<t>		<li>
	If there is no byte-range lock stateid, then the OPEN stateid for the open		If there is no byte-range lock stateid, then the OPEN stateid for the open
	file in question SHOULD be used.		file in question <bcp14>SHOULD</bcp14> be used.
	</t>		</li>
	<t>		<li>
	Finally, if none of the above apply, then a special stateid		Finally, if none of the above apply, then a special stateid
	SHOULD be used.		<bcp14>SHOULD</bcp14> be used.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Ignoring these rules may result in situations in which the server		Ignoring these rules may result in situations in which the server
	does not have information necessary to properly process the request.		does not have information necessary to properly process the request.
	For example, when mandatory byte-range locks are in effect, if the		For example, when mandatory byte-range locks are in effect, if the
	stateid does not indicate the proper lock-owner, via a lock stateid,		stateid does not indicate the proper lock-owner, via a lock stateid,
	a request might be avoidably rejected.		a request might be avoidably rejected.
	</t>		</t>
	<t>		<t>
	The server however should not try to enforce these ordering rules		The server however should not try to enforce these ordering rules
	and should use whatever information is available to properly process		and should use whatever information is available to properly process
	I/O requests. In particular, when a client has a delegation for a give n file, it		I/O requests. In particular, when a client has a delegation for a give n file, it
	SHOULD take note of this fact in processing a request, even if it is		<bcp14>SHOULD</bcp14> take note of this fact in processing a request, even if it is
	sent with a special stateid.		sent with a special stateid.
	</t>		</t>
	</section> <!-- "Stateid Use for I/O Operations" -->		</section>
	<section anchor="stateid_use_sa" title="Stateid Use for SETATTR Operations		<section anchor="stateid_use_sa" numbered="true" toc="default">
	">		<name>Stateid Use for SETATTR Operations</name>
	<t>		<t>
	Because each operation is associated with a session ID and from that		Because each operation is associated with a session ID and from that
	the clientid can be determined, operations do not need to		the clientid can be determined, operations do not need to
	include a stateid for the server to be able to determine whether		include a stateid for the server to be able to determine whether
	they should cause a delegation to be recalled or are to be		they should cause a delegation to be recalled or are to be
	treated as done within the scope of the delegation.		treated as done within the scope of the delegation.
	</t>		</t>
	<t>		<t>
	In the case of SETATTR operations, a stateid is present. In cases		In the case of SETATTR operations, a stateid is present. In cases
	other than those that set the file size, the client may send either		other than those that set the file size, the client may send either
	a special stateid or, when a delegation is held for the file in		a special stateid or, when a delegation is held for the file in
	question, a delegation stateid. While the server SHOULD validate		question, a delegation stateid. While the server <bcp14>SHOULD</bcp14 > validate
	the stateid and may use the stateid to optimize the determination		the stateid and may use the stateid to optimize the determination
	as to whether a delegation is held, it SHOULD note the presence of		as to whether a delegation is held, it <bcp14>SHOULD</bcp14> note the
	a delegation even when a special stateid is sent, and MUST accept a		presence of
			a delegation even when a special stateid is sent, and <bcp14>MUST</bcp
			14> accept a
	valid delegation stateid when sent.		valid delegation stateid when sent.
	</t>		</t>
	</section> <!-- "Stateid Use for SETATTR Operations" -->		</section>
	</section> <!-- "Stateid Definition" -->		</section>
	<section anchor="lease_renewal" title="Lease Renewal" >		<section anchor="lease_renewal" numbered="true" toc="default">
	<t>		<name>Lease Renewal</name>
			<t>
	Each client/server pair, as represented by a client ID, has a single		Each client/server pair, as represented by a client ID, has a single
	lease.		lease.
	The purpose of the lease is to allow the client to indicate		The purpose of the lease is to allow the client to indicate
	to the server, in a low-overhead way, that it is active, and		to the server, in a low-overhead way, that it is active, and
	thus that the server is to retain the client's locks. This arrangement		thus that the server is to retain the client's locks. This arrangement
	allows the server to remove stale locking-related objects		allows the server to remove stale locking-related objects
	that are held by a client that has crashed or is otherwise		that are held by a client that has crashed or is otherwise
	unreachable, once the relevant lease expires. This in turn allows		unreachable, once the relevant lease expires. This in turn allows
	other clients to obtain conflicting locks without being		other clients to obtain conflicting locks without being
	delayed indefinitely by inactive or unreachable clients.		delayed indefinitely by inactive or unreachable clients.
	It is not a		It is not a
	mechanism for cache consistency and lease		mechanism for cache consistency and lease
	renewals may not be denied if the lease interval has not expired.		renewals may not be denied if the lease interval has not expired.
	</t>		</t>
	<t>		<t>
	Since each session is associated with a specific		Since each session is associated with a specific
	client (identified by the client's client ID), any		client (identified by the client's client ID), any
	operation sent on that session is an indication		operation sent on that session is an indication
	that the associated client is reachable. When a		that the associated client is reachable. When a
	request is sent for a given session, successful		request is sent for a given session, successful
	execution of a SEQUENCE operation (or successful		execution of a SEQUENCE operation (or successful
	retrieval of the result of SEQUENCE from the reply		retrieval of the result of SEQUENCE from the reply
	cache) on an unexpired lease will result in the		cache) on an unexpired lease will result in the
	lease being implicitly renewed, for the standard		lease being implicitly renewed, for the standard
	renewal period (equal to the lease_time attribute).		renewal period (equal to the lease_time attribute).
	</t>		</t>
	<t>		<t>
	If the client ID's lease has not expired when the		If the client ID's lease has not expired when the
	server receives a SEQUENCE operation, then the server		server receives a SEQUENCE operation, then the server
	MUST renew the lease. If the client ID's lease has expired		<bcp14>MUST</bcp14> renew the lease. If the client ID's lease has expired
	when the server receives a SEQUENCE operation, the		when the server receives a SEQUENCE operation, the
	server MAY renew the lease; this depends on whether		server <bcp14>MAY</bcp14> renew the lease; this depends on whether
	any state was revoked as a result of the client's		any state was revoked as a result of the client's
	failure to renew the lease before expiration.		failure to renew the lease before expiration.
	</t>		</t>
	<t>		<t>
	Absent other activity that would renew the lease, a COMPOUND		Absent other activity that would renew the lease, a COMPOUND
	consisting of a single SEQUENCE operation will suffice. The		consisting of a single SEQUENCE operation will suffice. The
	client should also take communication-related delays into		client should also take communication-related delays into
	account and take steps to ensure that the renewal messages		account and take steps to ensure that the renewal messages
	actually reach the server in good time. For example:		actually reach the server in good time. For example:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	When trunking is in effect, the client should		When trunking is in effect, the client should
	consider sending multiple requests on different		consider sending multiple requests on different
	connections, in order to ensure that renewal		connections, in order to ensure that renewal
	occurs, even in the event of blockage in the		occurs, even in the event of blockage in the
	path used for one of those connections.		path used for one of those connections.
	</t>		</li>
	<t>		<li>
			<t>
	Transport retransmission delays might become		Transport retransmission delays might become
	so large as to approach or exceed the length		so large as to approach or exceed the length
	of the lease period. This may be particularly		of the lease period. This may be particularly
	likely when the server is unresponsive due to		likely when the server is unresponsive due to
	a restart; see <xref target="reclaim_locks"		a restart; see <xref target="reclaim_locks" format="default"/>. If the
	/>. If the client implementation is not careful,		client implementation is not careful,
	transport retransmission delays can result in the		transport retransmission delays can result in the
	client failing to detect a server restart before		client failing to detect a server restart before
	the grace period ends. The scenario is that the		the grace period ends. The scenario is that the
	client is using a transport with exponential		client is using a transport with exponential
	backoff, such that the maximum retransmission		backoff, such that the maximum retransmission
	timeout exceeds both the grace period and the		timeout exceeds both the grace period and the
	lease_time attribute. A network partition causes		lease_time attribute. A network partition causes
	the client's connection's retransmission interval		the client's connection's retransmission interval
	to back off, and even after the partition heals,		to back off, and even after the partition heals,
	the next transport-level retransmission is sent		the next transport-level retransmission is sent
	after the server has restarted and its grace		after the server has restarted and its grace
	period ends.		period ends.
	<vspace blankLines="1" />		</t>
			<t>
	The client MUST either recover from the ensuing		The client <bcp14>MUST</bcp14> either recover from the ensuing
	NFS4ERR_NO_GRACE errors or it MUST ensure that,		NFS4ERR_NO_GRACE errors or it <bcp14>MUST</bcp14> ensure that,
	despite transport-level retransmission intervals		despite transport-level retransmission intervals
	that exceed the lease_time, a SEQUENCE operation is sent		that exceed the lease_time, a SEQUENCE operation is sent
	that renews the lease before expiration. The client can achieve this		that renews the lease before expiration. The client can achieve this
	by associating a new connection with the session,		by associating a new connection with the session,
	and sending a SEQUENCE operation on it. However, if		and sending a SEQUENCE operation on it. However, if
	the attempt to establish a new connection is delayed		the attempt to establish a new connection is delayed
	for some reason (e.g., exponential backoff of the connection		for some reason (e.g., exponential backoff of the connection
	establishment packets), the client will have to		establishment packets), the client will have to
	abort the connection establishment attempt before		abort the connection establishment attempt before
	the lease expires, and attempt to reconnect.		the lease expires, and attempt to reconnect.
	</t>		</t>
	</list>		</li>
	</t>		</ul>
	<t>		<t>
	If the server renews the lease upon receiving		If the server renews the lease upon receiving
	a SEQUENCE operation, the server MUST NOT allow the lease		a SEQUENCE operation, the server <bcp14>MUST NOT</bcp14> allow the lease
	to expire while the rest of the operations		to expire while the rest of the operations
	in the COMPOUND procedure's request are still		in the COMPOUND procedure's request are still
	executing. Once the last operation has finished, and		executing. Once the last operation has finished, and
	the response to COMPOUND has been sent, the server		the response to COMPOUND has been sent, the server
	MUST set the lease to expire no sooner than the		<bcp14>MUST</bcp14> set the lease to expire no sooner than the
	sum of current time and the value of the lease_time attribute.		sum of current time and the value of the lease_time attribute.
	</t>		</t>
	<t>		<t>
	A client ID's lease can expire when it has been		A client ID's lease can expire when it has been
	at least the lease interval (lease_time) since the		at least the lease interval (lease_time) since the
	last lease-renewing SEQUENCE operation was sent		last lease-renewing SEQUENCE operation was sent
	on any of the client ID's sessions and there		on any of the client ID's sessions and there
	are no active COMPOUND operations on any such sessions.		are no active COMPOUND operations on any such sessions.
	</t>		</t>
	<t>		<t>
	Because the SEQUENCE operation is the basic mechanism to renew		Because the SEQUENCE operation is the basic mechanism to renew
	a lease, and because it must be done at least once for each		a lease, and because it must be done at least once for each
	lease period, it is the natural mechanism whereby the server		lease period, it is the natural mechanism whereby the server
	will inform the client of changes in the lease status that the		will inform the client of changes in the lease status that the
	client needs to be informed of. The client should inspect the		client needs to be informed of. The client should inspect the
	status flags (sr_status_flags) returned by sequence and take		status flags (sr_status_flags) returned by sequence and take
	the appropriate action (see		the appropriate action (see
	<xref target="OP_SEQUENCE_DESCRIPTION" /> for details).		<xref target="OP_SEQUENCE_DESCRIPTION" format="default"/> for details).
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The status bits SEQ4_STATUS_CB_PATH_DOWN and		The status bits SEQ4_STATUS_CB_PATH_DOWN and
	SEQ4_STATUS_CB_PATH_DOWN_SESSION indicate problems with		SEQ4_STATUS_CB_PATH_DOWN_SESSION indicate problems with
	the backchannel that the client may need to address		the backchannel that the client may need to address
	in order to receive callback requests.		in order to receive callback requests.
	</t>		</li>
	<t>		<li>
	The status bits SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRING and		The status bits SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRING and
	SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRED indicate		SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRED indicate
	problems with GSS contexts or RPCSEC_GSS handles		problems with GSS contexts or RPCSEC_GSS handles
	for the backchannel that the		for the backchannel that the
	client might have to address in order to allow callback requests		client might have to address in order to allow callback requests
	to be sent.		to be sent.
	</t>		</li>
	<t>		<li>
	The status bits SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED,		The status bits SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED,
	SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED,		SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED,
	SEQ4_STATUS_ADMIN_STATE_REVOKED, and		SEQ4_STATUS_ADMIN_STATE_REVOKED, and
	SEQ4_STATUS_RECALLABLE_STATE_REVOKED notify the		SEQ4_STATUS_RECALLABLE_STATE_REVOKED notify the
	client of lock revocation events. When these bits		client of lock revocation events. When these bits
	are set, the client should use TEST_STATEID to find		are set, the client should use TEST_STATEID to find
	what stateids have been revoked and use FREE_STATEID		what stateids have been revoked and use FREE_STATEID
	to acknowledge loss of the associated state.		to acknowledge loss of the associated state.
	</t>		</li>
	<t>		<li>
	The status bit SEQ4_STATUS_LEASE_MOVE		The status bit SEQ4_STATUS_LEASE_MOVE
	indicates that		indicates that
	responsibility for lease renewal has been transferred to		responsibility for lease renewal has been transferred to
	one or more new servers.		one or more new servers.
	</t>		</li>
	<t>		<li>
	The status bit SEQ4_STATUS_RESTART_RECLAIM_NEEDED		The status bit SEQ4_STATUS_RESTART_RECLAIM_NEEDED
	indicates that due to server		indicates that due to server
	restart the client must reclaim locking state.		restart the client must reclaim locking state.
	</t>		</li>
	<t>		<li>
	The status bit SEQ4_STATUS_BACKCHANNEL_FAULT		The status bit SEQ4_STATUS_BACKCHANNEL_FAULT
	indicates that the server has encountered an unrecoverable fault		indicates that the server has encountered an unrecoverable fault
	with the backchannel (e.g., it has lost track of a		with the backchannel (e.g., it has lost track of a
	sequence ID for a slot in the backchannel).		sequence ID for a slot in the backchannel).
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section> <!-- "Lease Renewal" -->		<section anchor="lock_crash_recovery" numbered="true" toc="default">
	<section title="Crash Recovery" anchor="lock_crash_recovery" >		<name>Crash Recovery</name>
	<t>		<t>
	A critical requirement in crash recovery is that both the client		A critical requirement in crash recovery is that both the client
	and the server know when the other has failed. Additionally, it		and the server know when the other has failed. Additionally, it
	is required that a client sees a consistent view of data across		is required that a client sees a consistent view of data across
	server restarts. All READ and WRITE operations that		server restarts. All READ and WRITE operations that
	may have been queued within the client or network buffers must		may have been queued within the client or network buffers must
	wait until the client has successfully recovered the locks		wait until the client has successfully recovered the locks
	protecting the READ and WRITE operations. Any that reach the		protecting the READ and WRITE operations. Any that reach the
	server before the server can safely determine that the client		server before the server can safely determine that the client
	has recovered enough locking state to be sure that such		has recovered enough locking state to be sure that such
	operations can be safely processed must be rejected.		operations can be safely processed must be rejected.
	This will happen because either:		This will happen because either:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	The state presented is no longer valid since it is		The state presented is no longer valid since it is
	associated with a now invalid client ID. In this case, the		associated with a now invalid client ID. In this case, the
	client will receive either an NFS4ERR_BADSESSION or		client will receive either an NFS4ERR_BADSESSION or
	NFS4ERR_DEADSESSION error, and any attempt to attach a new		NFS4ERR_DEADSESSION error, and any attempt to attach a new
	session to that invalid client ID will result in an		session to that invalid client ID will result in an
	NFS4ERR_STALE_CLIENTID error.		NFS4ERR_STALE_CLIENTID error.
	</t>		</li>
	<t>		<li>
	Subsequent recovery of locks may make execution of the		Subsequent recovery of locks may make execution of the
	operation inappropriate (NFS4ERR_GRACE).		operation inappropriate (NFS4ERR_GRACE).
	</t>		</li>
	</list>		</ul>
	</t>		<section numbered="true" toc="default">
	<section title="Client Failure and Recovery" >		<name>Client Failure and Recovery</name>
	<t>		<t>
	In the event that a client fails, the server may release the		In the event that a client fails, the server may release the
	client's locks when the associated lease has expired. Conflicting		client's locks when the associated lease has expired. Conflicting
	locks from another client may only be granted after this lease		locks from another client may only be granted after this lease
	expiration. As discussed in <xref target="lease_renewal" />, when		expiration. As discussed in <xref target="lease_renewal" format="defaul t"/>, when
	a client has not failed and re-establishes its lease before expiration		a client has not failed and re-establishes its lease before expiration
	occurs, requests for conflicting locks will not be granted.		occurs, requests for conflicting locks will not be granted.
	</t>		</t>
	<t>		<t>
	To minimize client delay upon restart, lock requests are associated		To minimize client delay upon restart, lock requests are associated
	with an instance of the client by a client-supplied verifier. This		with an instance of the client by a client-supplied verifier. This
	verifier is part of the client_owner4 sent in the initial		verifier is part of the client_owner4 sent in the initial
	EXCHANGE_ID call made by the client.		EXCHANGE_ID call made by the client.
	The server returns a client ID as a result of the EXCHANGE_ID		The server returns a client ID as a result of the EXCHANGE_ID
	operation. The client then confirms the use of the client ID by		operation. The client then confirms the use of the client ID by
	establishing a session associated with that client ID (see		establishing a session associated with that client ID (see
	<xref target='OP_CREATE_SESSION_DESCRIPTION' /> for a		<xref target="OP_CREATE_SESSION_DESCRIPTION" format="default"/> for a
	description of how this is done). All locks,		description of how this is done). All locks,
	including opens, byte-range locks, delegations, and layouts obtained		including opens, byte-range locks, delegations, and layouts obtained
	by sessions using that client ID, are associated with that client ID.		by sessions using that client ID, are associated with that client ID.
	</t>		</t>
	<t>		<t>
	Since the verifier will be changed by the client upon each		Since the verifier will be changed by the client upon each
	initialization, the server can compare a new verifier to the verifier		initialization, the server can compare a new verifier to the verifier
	associated with currently held locks and determine that they do not		associated with currently held locks and determine that they do not
	match. This signifies the client's new instantiation and subsequent		match. This signifies the client's new instantiation and subsequent
	loss (upon confirmation of the new client ID) of locking		loss (upon confirmation of the new client ID) of locking
	state. As a result, the server is free to release all		state. As a result, the server is free to release all
	locks held that are associated with the old client ID that was		locks held that are associated with the old client ID that was
	derived from the old verifier. At this point, conflicting locks from		derived from the old verifier. At this point, conflicting locks from
	other clients, kept waiting while the lease had not yet expired, can		other clients, kept waiting while the lease had not yet expired, can
	be granted. In addition, all stateids associated with the old client ID		be granted. In addition, all stateids associated with the old client ID
	can also be freed, as they are no longer reference-able.		can also be freed, as they are no longer reference-able.
	</t>		</t>
	<t>		<t>
	Note that the verifier must have the same uniqueness properties as the		Note that the verifier must have the same uniqueness properties as the
	verifier for the COMMIT operation.		verifier for the COMMIT operation.
	</t>		</t>
	</section> <!-- "Client Failure and Recovery" -->		</section>
	<section anchor="server_failure" title="Server Failure and Recovery" >		<section anchor="server_failure" numbered="true" toc="default">
	<t>		<name>Server Failure and Recovery</name>
			<t>
	If the server loses locking state (usually as a result of a restart), it must allow clients time to discover this fact and		If the server loses locking state (usually as a result of a restart), it must allow clients time to discover this fact and
	re-establish the lost locking state. The client must be able to		re-establish the lost locking state. The client must be able to
	re-establish the locking state without having the server deny valid		re-establish the locking state without having the server deny valid
	requests because the server has granted conflicting access to another		requests because the server has granted conflicting access to another
	client. Likewise, if there is a possibility that clients have not		client. Likewise, if there is a possibility that clients have not
	yet re-established their locking state for a file and that		yet re-established their locking state for a file and that
	such locking state might make it invalid to perform READ or		such locking state might make it invalid to perform READ or
	WRITE operations. For example, if mandatory locks are a possibility,		WRITE operations. For example, if mandatory locks are a possibility,
	the server must disallow READ and WRITE operations for that file.		the server must disallow READ and WRITE operations for that file.
	</t>		</t>
	<t>		<t>
	A client can determine that loss of locking		A client can determine that loss of locking
	state has occurred via several methods.		state has occurred via several methods.
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	When a SEQUENCE (most common) or other operation returns		When a SEQUENCE (most common) or other operation returns
	NFS4ERR_BADSESSION, this may mean that the session has		NFS4ERR_BADSESSION, this may mean that the session has
	been destroyed but the client ID is still valid.		been destroyed but the client ID is still valid.
	The client sends a CREATE_SESSION request with the		The client sends a CREATE_SESSION request with the
	client ID to re-establish the session. If		client ID to re-establish the session. If
	CREATE_SESSION fails with NFS4ERR_STALE_CLIENTID,		CREATE_SESSION fails with NFS4ERR_STALE_CLIENTID,
	the client must establish a new client ID (see		the client must establish a new client ID (see
	<xref target="client_id" />) and re-establish its		<xref target="client_id" format="default"/>) and re-establish its
	lock state with the new client ID, after the CREATE_SESSION		lock state with the new client ID, after the CREATE_SESSION
	operation succeeds (see <xref target="reclaim_locks" />).		operation succeeds (see <xref target="reclaim_locks" format="default"/>) .
	</t>		</li>
	<t>		<li>
	When a SEQUENCE (most common) or other operation on a		When a SEQUENCE (most common) or other operation on a
	persistent session returns NFS4ERR_DEADSESSION, this indicates		persistent session returns NFS4ERR_DEADSESSION, this indicates
	that a session is no longer usable for new, i.e., not satisfied		that a session is no longer usable for new, i.e., not satisfied
	from the reply cache, operations. Once all pending operations		from the reply cache, operations. Once all pending operations
	are determined to be either performed before the retry or not		are determined to be either performed before the retry or not
	performed, the client sends a CREATE_SESSION request with the		performed, the client sends a CREATE_SESSION request with the
	client ID to re-establish the session. If		client ID to re-establish the session. If
	CREATE_SESSION fails with NFS4ERR_STALE_CLIENTID,		CREATE_SESSION fails with NFS4ERR_STALE_CLIENTID,
	the client must establish a new client ID (see		the client must establish a new client ID (see
	<xref target="client_id" />) and re-establish its		<xref target="client_id" format="default"/>) and re-establish its
	lock state after the CREATE_SESSION, with the		lock state after the CREATE_SESSION, with the
	new client ID, succeeds		new client ID, succeeds
	(<xref target="reclaim_locks" />).		(<xref target="reclaim_locks" format="default"/>).
	</t>		</li>
	<t>		<li>
	When an operation, neither SEQUENCE nor preceded by SEQUENCE (for		When an operation, neither SEQUENCE nor preceded by SEQUENCE (for
	example, CREATE_SESSION, DESTROY_SESSION), returns		example, CREATE_SESSION, DESTROY_SESSION), returns
	NFS4ERR_STALE_CLIENTID, the client MUST establish		NFS4ERR_STALE_CLIENTID, the client <bcp14>MUST</bcp14> establish
	a new client ID (<xref target="client_id" />) and		a new client ID (<xref target="client_id" format="default"/>) and
	re-establish its lock state (<xref		re-establish its lock state (<xref target="reclaim_locks" format="default
	target="reclaim_locks" />).		"/>).
	</t>		</li>
	</list>		</ol>
	</t>		<section anchor="reclaim_locks" numbered="true" toc="default">
	<section anchor="reclaim_locks" title="State Reclaim" >		<name>State Reclaim</name>
	<t>		<t>
	When state information and the associated locks are lost		When state information and the associated locks are lost
	as a result of a server restart, the protocol must provide		as a result of a server restart, the protocol must provide
	a way to cause that state to be re-established. The		a way to cause that state to be re-established. The
	approach used is to define, for most types of locking		approach used is to define, for most types of locking
	state (layouts are an exception), a request whose function		state (layouts are an exception), a request whose function
	is to allow the client to		is to allow the client to
	re-establish on the server a lock first obtained from a		re-establish on the server a lock first obtained from a
	previous instance. Generally, these requests are variants		previous instance. Generally, these requests are variants
	of the requests normally used to create locks of that type		of the requests normally used to create locks of that type
	and are referred to as "reclaim-type" requests, and the process		and are referred to as "reclaim-type" requests, and the process
	of re-establishing such locks is referred to as "reclaiming"		of re-establishing such locks is referred to as "reclaiming"
	them.		them.
	</t>		</t>
	<t anchor="read_write_grace">		<t anchor="read_write_grace">
	Because each client must have an opportunity to reclaim		Because each client must have an opportunity to reclaim
	all of the locks that it has without the possibility that		all of the locks that it has without the possibility that
	some other client will be granted a conflicting lock,		some other client will be granted a conflicting lock,
	a "grace period" is devoted		a "grace period" is devoted
	to the reclaim process. During this period, requests		to the reclaim process. During this period, requests
	creating client IDs and		creating client IDs and
	sessions are handled normally, but locking requests are		sessions are handled normally, but locking requests are
	subject to special restrictions. Only		subject to special restrictions. Only
	reclaim-type locking requests are allowed, unless the		reclaim-type locking requests are allowed, unless the
	server can reliably determine (through state		server can reliably determine (through state
	persistently maintained across restart instances) that		persistently maintained across restart instances) that
	granting any such lock cannot possibly conflict with a		granting any such lock cannot possibly conflict with a
	subsequent reclaim.		subsequent reclaim.
	When a request is made to obtain		When a request is made to obtain
	a new lock (i.e., not a reclaim-type request) during the		a new lock (i.e., not a reclaim-type request) during the
	grace period and such a determination cannot be made,		grace period and such a determination cannot be made,
	the server must return the error NFS4ERR_GRACE.		the server must return the error NFS4ERR_GRACE.
	</t>		</t>
	<t>		<t>
	Once a session is established using the new client ID, the		Once a session is established using the new client ID, the
	client will use reclaim-type locking requests (e.g., LOCK		client will use reclaim-type locking requests (e.g., LOCK
	operations with reclaim set to TRUE and OPEN operations with a		operations with reclaim set to TRUE and OPEN operations with a
	claim type of CLAIM_PREVIOUS; see		claim type of CLAIM_PREVIOUS; see
	<xref target="open_br_reclaim" />) to re-establish its locking		<xref target="open_br_reclaim" format="default"/>) to re-establish its l ocking
	state. Once this is done, or if there is no such locking		state. Once this is done, or if there is no such locking
	state to reclaim, the client sends a global RECLAIM_COMPLETE		state to reclaim, the client sends a global RECLAIM_COMPLETE
	operation, i.e., one with the rca_one_fs argument set to FALSE, to		operation, i.e., one with the rca_one_fs argument set to FALSE, to
	indicate that it has reclaimed all of the locking state that		indicate that it has reclaimed all of the locking state that
	it will reclaim. Once a client sends such a RECLAIM_COMPLETE		it will reclaim. Once a client sends such a RECLAIM_COMPLETE
	operation, it may attempt non-reclaim locking operations,		operation, it may attempt non-reclaim locking operations,
	although it might get an NFS4ERR_GRACE status result from each such oper ation until		although it might get an NFS4ERR_GRACE status result from each such oper ation until
	the period of special handling is over.		the period of special handling is over.
	See <xref target="SEC11-EFF-lock" /> for a discussion of the		See <xref target="SEC11-EFF-lock" format="default"/> for a discussion of the
	analogous handling lock reclamation in the case of file systems		analogous handling lock reclamation in the case of file systems
	transitioning from server to server.		transitioning from server to server.
	</t>		</t>
	<t>		<t>
	During the grace period, the server must reject READ		During the grace period, the server must reject READ
	and WRITE operations		and WRITE operations
	and non-reclaim locking requests (i.e., other LOCK		and non-reclaim locking requests (i.e., other LOCK
	and OPEN operations) with an error of NFS4ERR_GRACE,		and OPEN operations) with an error of NFS4ERR_GRACE,
	unless it can guarantee that these may be done		unless it can guarantee that these may be done
	safely, as described below.		safely, as described below.
	</t>		</t>
	<t>		<t>
	The grace period may last until all clients that are known to		The grace period may last until all clients that are known to
	possibly have had locks have done a global RECLAIM_COMPLETE operation, i ndicating		possibly have had locks have done a global RECLAIM_COMPLETE operation, i ndicating
	that they have finished reclaiming the locks they held before		that they have finished reclaiming the locks they held before
	the server restart. This means that a client that has done a		the server restart. This means that a client that has done a
	RECLAIM_COMPLETE must be prepared to receive an NFS4ERR_GRACE		RECLAIM_COMPLETE must be prepared to receive an NFS4ERR_GRACE
	when attempting to acquire new locks.		when attempting to acquire new locks.
	In order for the server to know that all clients with possible prior		In order for the server to know that all clients with possible prior
	lock state have done a RECLAIM_COMPLETE,		lock state have done a RECLAIM_COMPLETE,
	the server must maintain in stable		the server must maintain in stable
	storage a list clients that may have such locks. The server		storage a list clients that may have such locks. The server
	may also terminate the grace period before all clients have		may also terminate the grace period before all clients have
	done a global RECLAIM_COMPLETE. The server SHOULD NOT terminate the		done a global RECLAIM_COMPLETE. The server <bcp14>SHOULD NOT</bcp14> te rminate the
	grace period before a time equal to the lease period in order		grace period before a time equal to the lease period in order
	to give clients an opportunity to find out about the server		to give clients an opportunity to find out about the server
	restart, as a result of sending requests on associated		restart, as a result of sending requests on associated
	sessions with a frequency governed by the lease time.		sessions with a frequency governed by the lease time.
	Note that when a client does not send such requests (or they		Note that when a client does not send such requests (or they
	are sent by the client but not received by the server),		are sent by the client but not received by the server),
	it is possible for the grace period to expire before the client		it is possible for the grace period to expire before the client
	finds out that the server restart has occurred.		finds out that the server restart has occurred.
	</t>		</t>
	<t>		<t>
	Some additional time in		Some additional time in
	order to allow a client to		order to allow a client to
	establish a new client ID and session and to effect lock		establish a new client ID and session and to effect lock
	reclaims may be added to the lease time. Note that		reclaims may be added to the lease time. Note that
	analogous rules apply to		analogous rules apply to
	file system-specific grace periods discussed in		file system-specific grace periods discussed in
	<xref target="SEC11-EFF-lock"/>.		<xref target="SEC11-EFF-lock" format="default"/>.
	</t>		</t>
	<t>		<t>
	If the server can reliably determine that granting a non-reclaim		If the server can reliably determine that granting a non-reclaim
	request will not conflict with reclamation of locks by other		request will not conflict with reclamation of locks by other
	clients, the NFS4ERR_GRACE error does not have to be returned		clients, the NFS4ERR_GRACE error does not have to be returned
	even within the grace period, although NFS4ERR_GRACE must always		even within the grace period, although NFS4ERR_GRACE must always
	be returned to clients attempting a non-reclaim lock request		be returned to clients attempting a non-reclaim lock request
	before doing their own global RECLAIM_COMPLETE.		before doing their own global RECLAIM_COMPLETE.
	For the server to be able		For the server to be able
	to service READ and WRITE operations during the grace period, it must		to service READ and WRITE operations during the grace period, it must
	again be able to guarantee that no possible conflict could arise		again be able to guarantee that no possible conflict could arise
	between a potential reclaim locking request and the READ or WRITE		between a potential reclaim locking request and the READ or WRITE
	operation. If the server is unable to offer that guarantee, the		operation. If the server is unable to offer that guarantee, the
	NFS4ERR_GRACE error must be returned to the client.		NFS4ERR_GRACE error must be returned to the client.
	</t>		</t>
	<t>		<t>
	For a server to provide simple, valid handling during the grace		For a server to provide simple, valid handling during the grace
	period, the easiest method is to simply reject all non-reclaim locking		period, the easiest method is to simply reject all non-reclaim locking
	requests and READ and WRITE operations by returning the NFS4ERR_GRACE		requests and READ and WRITE operations by returning the NFS4ERR_GRACE
	error. However, a server may keep information about granted locks in		error. However, a server may keep information about granted locks in
	stable storage. With this information, the server could determine if		stable storage. With this information, the server could determine if
	a locking, READ or WRITE operation can be safely processed.		a locking, READ or WRITE operation can be safely processed.
	</t>		</t>
	<t>		<t>
	For example, if the server maintained on stable storage summary		For example, if the server maintained on stable storage summary
	information on whether mandatory locks exist, either mandatory		information on whether mandatory locks exist, either mandatory
	byte-range locks, or share reservations specifying deny modes,		byte-range locks, or share reservations specifying deny modes,
	many requests could be allowed during the grace period. If it		many requests could be allowed during the grace period. If it
	is known that no such share reservations exist, OPEN request that		is known that no such share reservations exist, OPEN request that
	do not specify deny modes may be safely granted. If, in addition,		do not specify deny modes may be safely granted. If, in addition,
	it is known that no mandatory byte-range locks exist, either		it is known that no mandatory byte-range locks exist, either
	through information stored on stable storage or simply because		through information stored on stable storage or simply because
	the server does not support such locks, READ and WRITE operations		the server does not support such locks, READ and WRITE operations
	may be safely processed during the grace period.		may be safely processed during the grace period.
	Another important case is where it is known that no mandatory		Another important case is where it is known that no mandatory
	byte-range locks exist, either because the server does not		byte-range locks exist, either because the server does not
	provide support for them or because their absence is known		provide support for them or because their absence is known
	from persistently recorded data. In this case, READ and		from persistently recorded data. In this case, READ and
	WRITE operations specifying stateids derived from reclaim-type		WRITE operations specifying stateids derived from reclaim-type
	operations may be validly processed during the grace period		operations may be validly processed during the grace period
	because of the fact that the valid reclaim ensures that no lock		because of the fact that the valid reclaim ensures that no lock
	subsequently granted can prevent the I/O.		subsequently granted can prevent the I/O.
	</t>		</t>
	<t>		<t>
	To reiterate, for a server that allows non-reclaim lock and I/O		To reiterate, for a server that allows non-reclaim lock and I/O
	requests to be processed during the grace period, it MUST determine		requests to be processed during the grace period, it <bcp14>MUST</bcp14> determine
	that no lock subsequently reclaimed will be rejected and that no lock		that no lock subsequently reclaimed will be rejected and that no lock
	subsequently reclaimed would have prevented any I/O operation		subsequently reclaimed would have prevented any I/O operation
	processed during the grace period.		processed during the grace period.
	</t>		</t>
	<t>		<t>
	Clients should be prepared for the return of NFS4ERR_GRACE errors for		Clients should be prepared for the return of NFS4ERR_GRACE errors for
	non-reclaim lock and I/O requests. In this case, the client should		non-reclaim lock and I/O requests. In this case, the client should
	employ a retry mechanism for the request. A delay (on the order of		employ a retry mechanism for the request. A delay (on the order of
	several seconds) between retries should be used to avoid overwhelming		several seconds) between retries should be used to avoid overwhelming
	the server. Further discussion of the general issue is included in		the server. Further discussion of the general issue is included in
	<xref target="Floyd" />. The client must account for the server that		<xref target="Floyd" format="default"/>. The client must account for th e server that
	can perform I/O and non-reclaim locking requests within the grace period		can perform I/O and non-reclaim locking requests within the grace period
	as well as those that cannot do so.		as well as those that cannot do so.
	</t>		</t>
	<t>		<t>
	A reclaim-type locking request outside the server's grace period		A reclaim-type locking request outside the server's grace period
	can only succeed if the server can guarantee that no conflicting		can only succeed if the server can guarantee that no conflicting
	lock or I/O request has been granted since restart.		lock or I/O request has been granted since restart.
	</t>		</t>
	<t>		<t>
	A server may, upon restart, establish a new value for the lease		A server may, upon restart, establish a new value for the lease
	period. Therefore, clients should, once a new client ID is		period. Therefore, clients should, once a new client ID is
	established, refetch the lease_time attribute and use it as the basis		established, refetch the lease_time attribute and use it as the basis
	for lease renewal for the lease associated with that server. However,		for lease renewal for the lease associated with that server. However,
	the server must establish, for this restart event, a grace period at		the server must establish, for this restart event, a grace period at
	least as long as the lease period for the previous server		least as long as the lease period for the previous server
	instantiation. This allows the client state obtained during the		instantiation. This allows the client state obtained during the
	previous server instance to be reliably re-established.		previous server instance to be reliably re-established.
	</t>		</t>
	<t>		<t>
	The possibility exists that, because of server configuration		The possibility exists that, because of server configuration
	events, the client will be communicating with a server		events, the client will be communicating with a server
	different than the one on which the locks were obtained, as		different than the one on which the locks were obtained, as
	shown by the combination of eir_server_scope and		shown by the combination of eir_server_scope and
	eir_server_owner. This leads to the issue of if and when		eir_server_owner. This leads to the issue of if and when
	the client should attempt to reclaim locks previously obtained		the client should attempt to reclaim locks previously obtained
	on what is being reported as a different server. The rules		on what is being reported as a different server. The rules
	to resolve this question are as follows:		to resolve this question are as follows:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	If the server scope is different, the client should not		If the server scope is different, the client should not
	attempt to reclaim locks. In this situation, no lock		attempt to reclaim locks. In this situation, no lock
	reclaim is possible. Any attempt to re-obtain the locks		reclaim is possible. Any attempt to re-obtain the locks
	with non-reclaim operations is problematic since there is		with non-reclaim operations is problematic since there is
	no guarantee that the existing filehandles will be recognized		no guarantee that the existing filehandles will be recognized
	by the new server, or that if recognized, they denote the		by the new server, or that if recognized, they denote the
	same objects. It is best to treat the locks as having been		same objects. It is best to treat the locks as having been
	revoked by the reconfiguration event.		revoked by the reconfiguration event.
	</t>		</li>
	<t>		<li>
	If the server scope is the same, the client should attempt		If the server scope is the same, the client should attempt
	to reclaim locks, even if the eir_server_owner value is		to reclaim locks, even if the eir_server_owner value is
	different. In this situation, it is the responsibility		different. In this situation, it is the responsibility
	of the server to return NFS4ERR_NO_GRACE if it cannot		of the server to return NFS4ERR_NO_GRACE if it cannot
	provide correct support for lock reclaim operations,		provide correct support for lock reclaim operations,
	including the prevention of edge conditions.		including the prevention of edge conditions.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The eir_server_owner field is not used in making this		The eir_server_owner field is not used in making this
	determination. Its function is to specify trunking		determination. Its function is to specify trunking
	possibilities for the client (see <xref target="Trunking" />)		possibilities for the client (see <xref target="Trunking" format="defaul t"/>)
	and not to control lock reclaim.		and not to control lock reclaim.
	</t>		</t>
	<section anchor="reclaim_security_considerations"		<section anchor="reclaim_security_considerations" numbered="true" to
	title="Security Considerations for State Reclaim" >		c="default">
	<t>		<name>Security Considerations for State Reclaim</name>
			<t>
	During the grace period, a client can reclaim state that it believes o r		During the grace period, a client can reclaim state that it believes o r
	asserts it had before the server restarted. Unless the server		asserts it had before the server restarted. Unless the server
	maintained a complete record of all the state the client had,		maintained a complete record of all the state the client had,
	the server has little choice but to trust the client. (Of course,		the server has little choice but to trust the client. (Of course,
	if the server maintained a complete record, then it would not		if the server maintained a complete record, then it would not
	have to force the client to reclaim state after server restart.)		have to force the client to reclaim state after server restart.)
	While the server has to trust the client to tell the truth, the		While the server has to trust the client to tell the truth, the
	negative consequences for security are limited to enabling		negative consequences for security are limited to enabling
	denial-of-service attacks in situations in which AUTH_SYS is		denial-of-service attacks in situations in which AUTH_SYS is
	supported. The		supported. The
	fundamental rule for the server when processing reclaim requests		fundamental rule for the server when processing reclaim requests
	is that it MUST NOT grant the reclaim if an equivalent non-reclaim		is that it <bcp14>MUST NOT</bcp14> grant the reclaim if an equivalent non-reclaim
	request would not be granted during steady state due to access		request would not be granted during steady state due to access
	control or access conflict issues. For example, an OPEN request		control or access conflict issues. For example, an OPEN request
	during a reclaim will be refused with NFS4ERR_ACCESS if the principal m aking		during a reclaim will be refused with NFS4ERR_ACCESS if the principal m aking
	the request does not have access to open the file according to the		the request does not have access to open the file according to the
	discretionary ACL (<xref target="attrdef_dacl"/>) on the file.		discretionary ACL (<xref target="attrdef_dacl" format="default"/>) on t
			he file.
	</t>
	<t>		</t>
			<t>
	Nonetheless, it is possible that a client operating in error or		Nonetheless, it is possible that a client operating in error or
	maliciously could, during reclaim, prevent another client from		maliciously could, during reclaim, prevent another client from
	reclaiming access to state. For example, an attacker could		reclaiming access to state. For example, an attacker could
	send an OPEN reclaim operation with a deny mode that prevents		send an OPEN reclaim operation with a deny mode that prevents
	another client from reclaiming the OPEN state it had before the		another client from reclaiming the OPEN state it had before the
	server restarted.		server restarted.
	The attacker could perform the same denial of service during		The attacker could perform the same denial of service during
	steady state prior to server restart, as long as the		steady state prior to server restart, as long as the
	attacker had permissions. Given that the attack		attacker had permissions. Given that the attack
	vectors are equivalent, the grace period does not offer any		vectors are equivalent, the grace period does not offer any
	additional opportunity for denial of service, and any concerns		additional opportunity for denial of service, and any concerns
	about this attack vector, whether during grace or steady state,		about this attack vector, whether during grace or steady state,
	are addressed the same way: use RPCSEC_GSS for authentication		are addressed the same way: use RPCSEC_GSS for authentication
	and limit access to the file only to principals that the owner of		and limit access to the file only to principals that the owner of
	the file trusts.		the file trusts.
	</t>		</t>
			<t>
	<t>
	Note that if prior to restart the server had client		Note that if prior to restart the server had client
	IDs with the EXCHGID4_FLAG_BIND_PRINC_STATEID (<xref		IDs with the EXCHGID4_FLAG_BIND_PRINC_STATEID (<xref target="OP_EXCH
	target="OP_EXCHANGE_ID"/>) capability set, then the server		ANGE_ID" format="default"/>) capability set, then the server
	SHOULD record in stable storage the client owner and the		<bcp14>SHOULD</bcp14> record in stable storage the client owner and t
			he
	principal that established the client ID via EXCHANGE_ID.		principal that established the client ID via EXCHANGE_ID.
	If the server does not, then there is a risk a client will		If the server does not, then there is a risk a client will
	be unable to reclaim state if it does not have a credential		be unable to reclaim state if it does not have a credential
	for a principal that was originally authorized to		for a principal that was originally authorized to
	establish the state.		establish the state.
	</t>		</t>
			</section>
	</section> <!-- "Security Considerations for State Reclaim" -->		</section>
	</section> <!-- "State Reclaim" -->		</section>
	</section> <!-- "Server Failure and Recovery" -->		<section anchor="network_partitions_and_recovery" numbered="true" toc="defau
	<section anchor="network_partitions_and_recovery"		lt">
	title="Network Partitions and Recovery">		<name>Network Partitions and Recovery</name>
	<t>		<t>
	If the duration of a network partition is greater than the lease		If the duration of a network partition is greater than the lease
	period provided by the server, the server will not have received a		period provided by the server, the server will not have received a
	lease renewal from the client. If this occurs, the server may free		lease renewal from the client. If this occurs, the server may free
	all locks held for the client or it may allow the lock state to		all locks held for the client or it may allow the lock state to
	remain for a considerable period, subject to the constraint that		remain for a considerable period, subject to the constraint that
	if a request for a conflicting lock is made, locks associated with		if a request for a conflicting lock is made, locks associated with
	an expired lease do not prevent such a conflicting lock from being		an expired lease do not prevent such a conflicting lock from being
	granted but MUST be revoked as necessary so as to avoid interfering with		granted but <bcp14>MUST</bcp14> be revoked as necessary so as to avoid i nterfering with
	such conflicting requests.		such conflicting requests.
	</t>		</t>
	<t>		<t>
	If the server chooses to delay freeing of lock state until there		If the server chooses to delay freeing of lock state until there
	is a conflict, it may either free all of the client's locks once		is a conflict, it may either free all of the client's locks once
	there is a conflict or it may only revoke the minimum set of locks		there is a conflict or it may only revoke the minimum set of locks
	necessary to allow conflicting requests. When it adopts the		necessary to allow conflicting requests. When it adopts the
	finer-grained approach, it must revoke all locks associated with a		finer-grained approach, it must revoke all locks associated with a
	given stateid, even if the conflict is with only a subset of locks.		given stateid, even if the conflict is with only a subset of locks.
	</t>		</t>
	<t>		<t>
	When the server chooses to free all of a client's lock state, either		When the server chooses to free all of a client's lock state, either
	immediately upon lease expiration or as a result of the first		immediately upon lease expiration or as a result of the first
	attempt to obtain a conflicting a lock, the server may report the		attempt to obtain a conflicting a lock, the server may report the
	loss of lock state in a number of ways.		loss of lock state in a number of ways.
	</t>		</t>
	<t>		<t>
	The server may choose to invalidate the session and the associated		The server may choose to invalidate the session and the associated
	client ID. In this case, once the client can communicate		client ID. In this case, once the client can communicate
	with the server, it will receive an NFS4ERR_BADSESSION error. Upon		with the server, it will receive an NFS4ERR_BADSESSION error. Upon
	attempting to create a new session, it would get an		attempting to create a new session, it would get an
	NFS4ERR_STALE_CLIENTID. Upon creating the new client ID and new		NFS4ERR_STALE_CLIENTID. Upon creating the new client ID and new
	session, the client will attempt to reclaim locks. Normally, the		session, the client will attempt to reclaim locks. Normally, the
	server will not allow the client to reclaim locks, because the		server will not allow the client to reclaim locks, because the
	server will not be in its recovery grace period.		server will not be in its recovery grace period.
	</t>		</t>
	<t>		<t>
	Another possibility is for the server to maintain the session and		Another possibility is for the server to maintain the session and
	client ID but for all stateids held by the		client ID but for all stateids held by the
	client to become invalid or stale. Once the client can reach		client to become invalid or stale. Once the client can reach
	the server after such a network partition, the status returned by		the server after such a network partition, the status returned by
	the SEQUENCE operation will indicate a loss of locking state; i.e.,		the SEQUENCE operation will indicate a loss of locking state; i.e.,
	the flag SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED will be set in		the flag SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED will be set in
	sr_status_flags. In		sr_status_flags. In
	addition, all I/O submitted by the		addition, all I/O submitted by the
	client with the now invalid stateids will fail with the server		client with the now invalid stateids will fail with the server
	returning the error NFS4ERR_EXPIRED. Once the client learns of		returning the error NFS4ERR_EXPIRED. Once the client learns of
	the loss of locking state, it		the loss of locking state, it
	will suitably notify the applications that held the invalidated		will suitably notify the applications that held the invalidated
	locks. The client should then take action to free invalidated		locks. The client should then take action to free invalidated
	stateids, either by establishing a new client ID using a new		stateids, either by establishing a new client ID using a new
	verifier or by doing a FREE_STATEID operation to release each		verifier or by doing a FREE_STATEID operation to release each
	of the invalidated stateids.		of the invalidated stateids.
	</t>		</t>
	<t>		<t>
	When the server adopts a finer-grained approach to revocation		When the server adopts a finer-grained approach to revocation
	of locks when a client's lease has expired, only a subset of stateids		of locks when a client's lease has expired, only a subset of stateids
	will normally become invalid during a network partition.		will normally become invalid during a network partition.
	When the client can communicate with the server after such a		When the client can communicate with the server after such a
	network partition heals, the status returned by the SEQUENCE		network partition heals, the status returned by the SEQUENCE
	operation will indicate a partial loss of locking state		operation will indicate a partial loss of locking state
	(SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED).		(SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED).
	In addition, operations, including I/O submitted by the		In addition, operations, including I/O submitted by the
	client, with the now invalid stateids will fail with the server		client, with the now invalid stateids will fail with the server
	returning the error NFS4ERR_EXPIRED. Once the client learns of		returning the error NFS4ERR_EXPIRED. Once the client learns of
	the loss of locking state, it will use the TEST_STATEID operation		the loss of locking state, it will use the TEST_STATEID operation
	on all of its stateids to		on all of its stateids to
	determine which locks have been lost and then		determine which locks have been lost and then
	suitably notify the applications that held the invalidated		suitably notify the applications that held the invalidated
	locks. The client can then release the invalidated locking		locks. The client can then release the invalidated locking
	state and acknowledge the revocation of the associated locks		state and acknowledge the revocation of the associated locks
	by doing a FREE_STATEID operation on each of the invalidated		by doing a FREE_STATEID operation on each of the invalidated
	stateids.		stateids.
	</t>		</t>
	<t>		<t>
	When a network partition is combined with a server restart, there are		When a network partition is combined with a server restart, there are
	edge conditions that place requirements on the server in order to		edge conditions that place requirements on the server in order to
	avoid silent data corruption following the server restart. Two of these		avoid silent data corruption following the server restart. Two of these
	edge conditions are known, and are discussed below.		edge conditions are known, and are discussed below.
	</t>		</t>
	<t>		<t>
	The first edge condition arises as a result of the scenarios such as		The first edge condition arises as a result of the scenarios such as
	the following:		the following:
	<list style='numbers'>
	<t>
	Client A acquires a lock.
	</t>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
			Client A acquires a lock.
			</li>
			<li>
	Client A and server experience mutual network partition, such that		Client A and server experience mutual network partition, such that
	client A is unable to renew its lease.		client A is unable to renew its lease.
	</t>		</li>
	<t>		<li>
	Client A's lease expires, and the server releases the lock.		Client A's lease expires, and the server releases the lock.
	</t>		</li>
	<t>		<li>
	Client B acquires a lock that would have conflicted		Client B acquires a lock that would have conflicted
	with that of client A.		with that of client A.
	</t>		</li>
	<t>		<li>
	Client B releases its lock.		Client B releases its lock.
	</t>		</li>
	<t>		<li>
	Server restarts.		Server restarts.
	</t>		</li>
	<t>		<li>
	Network partition between client A and server heals.		Network partition between client A and server heals.
	</t>		</li>
	<t>		<li>
	Client A connects to a new server instance and finds out about		Client A connects to a new server instance and finds out about
	server restart.		server restart.
	</t>		</li>
	<t>		<li>
	Client A reclaims its lock within the server's grace period.		Client A reclaims its lock within the server's grace period.
	</t>		</li>
	</list>		</ol>
	</t>		<t>
	<t>
	Thus, at the final step, the server has erroneously granted client A's		Thus, at the final step, the server has erroneously granted client A's
	lock reclaim. If client B modified the object the lock was protecting,		lock reclaim. If client B modified the object the lock was protecting,
	client A will experience object corruption.		client A will experience object corruption.
	</t>
	<t>
	The second known edge condition arises in situations such as the followi
	ng:
	<list style="numbers">
	<t>
	Client A acquires one or more locks.
	</t>		</t>
	<t>		<t>
	Server restarts.		The second known edge condition arises in situations such as the followi ng:
	</t>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
			Client A acquires one or more locks.
			</li>
			<li>
			Server restarts.
			</li>
			<li>
	Client A and server experience mutual network		Client A and server experience mutual network
	partition, such that client A is unable to reclaim		partition, such that client A is unable to reclaim
	all of its locks within the grace period.		all of its locks within the grace period.
	</t>		</li>
	<t>		<li>
	Server's reclaim grace period ends. Client A has either		Server's reclaim grace period ends. Client A has either
	no locks or an incomplete set of locks known to the server.		no locks or an incomplete set of locks known to the server.
	</t>		</li>
	<t>		<li>
	Client B acquires a lock that would have conflicted		Client B acquires a lock that would have conflicted
	with a lock of client A that was not reclaimed.		with a lock of client A that was not reclaimed.
	</t>		</li>
	<t>		<li>
	Client B releases the lock.		Client B releases the lock.
	</t>		</li>
	<t>		<li>
	Server restarts a second time.		Server restarts a second time.
	</t>		</li>
	<t>		<li>
	Network partition between client A and server heals.		Network partition between client A and server heals.
	</t>		</li>
	<t>		<li>
	Client A connects to new server instance and finds out about		Client A connects to new server instance and finds out about
	server restart.		server restart.
	</t>		</li>
	<t>		<li>
	Client A reclaims its lock within the server's		Client A reclaims its lock within the server's
	grace period.		grace period.
	</t>		</li>
	</list>		</ol>
	</t>		<t>
	<t>
	As with the first edge condition, the final step of the scenario of		As with the first edge condition, the final step of the scenario of
	the second edge condition has the server erroneously granting client		the second edge condition has the server erroneously granting client
	A's lock reclaim.		A's lock reclaim.
	</t>		</t>
	<t>		<t>
	Solving the first and second edge conditions requires either that the se rver		Solving the first and second edge conditions requires either that the se rver
	always assumes after it restarts that some edge condition		always assumes after it restarts that some edge condition
	occurs, and thus returns NFS4ERR_NO_GRACE for all reclaim attempts, or t hat the server		occurs, and thus returns NFS4ERR_NO_GRACE for all reclaim attempts, or t hat the server
	record some information in stable storage. The amount		record some information in stable storage. The amount
	of information the		of information the
	server records in stable storage is in inverse proportion to how harsh		server records in stable storage is in inverse proportion to how harsh
	the server intends to be whenever edge conditions arise.		the server intends to be whenever edge conditions arise.
	The server		The server
	that is completely tolerant of all edge conditions will record in		that is completely tolerant of all edge conditions will record in
	stable storage every lock that is acquired, removing the lock record		stable storage every lock that is acquired, removing the lock record
	from stable storage only when the lock is released.		from stable storage only when the lock is released.
	For the two edge conditions discussed above, the harshest a		For the two edge conditions discussed above, the harshest a
	server can be, and still support a grace period for reclaims, requires		server can be, and still support a grace period for reclaims, requires
	that the server record in stable storage some minimal		that the server record in stable storage some minimal
	information. For example, a server implementation could, for each		information. For example, a server implementation could, for each
	client, save in stable storage a record containing:		client, save in stable storage a record containing:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	the co_ownerid field from the client_owner4 presented in the		the co_ownerid field from the client_owner4 presented in the
	EXCHANGE_ID operation.		EXCHANGE_ID operation.
	</t>		</li>
	<t>		<li>
	a boolean that indicates if the client's lease expired		a boolean that indicates if the client's lease expired
	or if there was administrative intervention (see		or if there was administrative intervention (see
	<xref target="server_revocation" />) to revoke		<xref target="server_revocation" format="default"/>) to revoke
	a byte-range lock, share reservation, or delegation and		a byte-range lock, share reservation, or delegation and
	there has been no acknowledgment, via FREE_STATEID,		there has been no acknowledgment, via FREE_STATEID,
	of such revocation.		of such revocation.
	</t>		</li>
	<t>		<li>
	a boolean that indicates whether the client may have locks		a boolean that indicates whether the client may have locks
	that it believes to be reclaimable in situations in which the		that it believes to be reclaimable in situations in which the
	grace period was terminated, making the server's view of		grace period was terminated, making the server's view of
	lock reclaimability suspect. The server will set this for		lock reclaimability suspect. The server will set this for
	any client record in stable storage where the client has		any client record in stable storage where the client has
	not done a suitable RECLAIM_COMPLETE (global or file		not done a suitable RECLAIM_COMPLETE (global or file
	system-specific depending on the target of the lock		system-specific depending on the target of the lock
	request) before it grants any new (i.e., not reclaimed)		request) before it grants any new (i.e., not reclaimed)
	lock to any client.		lock to any client.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Assuming the above record keeping, for the first edge condition, after		Assuming the above record keeping, for the first edge condition, after
	the server restarts, the record that client A's lease expired means		the server restarts, the record that client A's lease expired means
	that another client could have acquired a conflicting byte-range lock,		that another client could have acquired a conflicting byte-range lock,
	share reservation, or delegation. Hence, the server must reject a		share reservation, or delegation. Hence, the server must reject a
	reclaim from client A with the error NFS4ERR_NO_GRACE.		reclaim from client A with the error NFS4ERR_NO_GRACE.
	</t>		</t>
	<t>		<t>
	For the second edge condition, after the server restarts for a second		For the second edge condition, after the server restarts for a second
	time, the indication that the client had not completed its		time, the indication that the client had not completed its
	reclaims at the time at which the grace period ended		reclaims at the time at which the grace period ended
	means that the server must reject a reclaim from client A		means that the server must reject a reclaim from client A
	with the error NFS4ERR_NO_GRACE.		with the error NFS4ERR_NO_GRACE.
	</t>		</t>
	<t>		<t>
	When either edge condition occurs, the client's attempt to reclaim		When either edge condition occurs, the client's attempt to reclaim
	locks will result in the error NFS4ERR_NO_GRACE. When this is		locks will result in the error NFS4ERR_NO_GRACE. When this is
	received, or after the client restarts with no lock state, the		received, or after the client restarts with no lock state, the
	client will send a global RECLAIM_COMPLETE. When		client will send a global RECLAIM_COMPLETE. When
	the RECLAIM_COMPLETE is received, the server and client are		the RECLAIM_COMPLETE is received, the server and client are
	again in agreement regarding reclaimable locks and both booleans in pers istent		again in agreement regarding reclaimable locks and both booleans in pers istent
	storage can be reset, to be set again only when there is a subsequent		storage can be reset, to be set again only when there is a subsequent
	event that causes lock reclaim operations to be questionable.		event that causes lock reclaim operations to be questionable.
	</t>		</t>
	<t>		<t>
	Regardless of the level and approach to record keeping, the server		Regardless of the level and approach to record keeping, the server
	MUST implement one of the following strategies (which apply to		<bcp14>MUST</bcp14> implement one of the following strategies (which app ly to
	reclaims of share reservations, byte-range locks, and delegations):		reclaims of share reservations, byte-range locks, and delegations):
	<list style="numbers">		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	Reject all reclaims with NFS4ERR_NO_GRACE. This		Reject all reclaims with NFS4ERR_NO_GRACE. This
	is extremely unforgiving, but necessary if the server does not		is extremely unforgiving, but necessary if the server does not
	record lock state in stable storage.		record lock state in stable storage.
	</t>		</li>
	<t>		<li>
			<t>
	Record sufficient state in stable storage such that		Record sufficient state in stable storage such that
	all known edge conditions involving server restart,		all known edge conditions involving server restart,
	including the two noted in this section, are		including the two noted in this section, are
	detected. It is acceptable to erroneously recognize an edge conditi on		detected. It is acceptable to erroneously recognize an edge conditi on
	and not allow a reclaim, when, with sufficient knowledge, it		and not allow a reclaim, when, with sufficient knowledge, it
	would be allowed. The error the server would return in this		would be allowed. The error the server would return in this
	case is NFS4ERR_NO_GRACE. Note that it is not known if there are ot her		case is NFS4ERR_NO_GRACE. Note that it is not known if there are ot her
	edge conditions.		edge conditions.
	<vspace blankLines='1' />		</t>
			<t>
	In the event that, after a server restart, the server		In the event that, after a server restart, the server
	determines there is unrecoverable damage or		determines there is unrecoverable damage or
	corruption to the information in stable storage, then for		corruption to the information in stable storage, then for
	all clients and/or locks that may be affected, the server MUST		all clients and/or locks that may be affected, the server <bcp14>MUS T</bcp14>
	return NFS4ERR_NO_GRACE.		return NFS4ERR_NO_GRACE.
	</t>		</t>
	</list>		</li>
	</t>		</ol>
	<t>		<t>
	A mandate for the client's handling of the NFS4ERR_NO_GRACE error is		A mandate for the client's handling of the NFS4ERR_NO_GRACE error is
	outside the scope of this specification, since the strategies for such		outside the scope of this specification, since the strategies for such
	handling are very dependent on the client's operating environment.		handling are very dependent on the client's operating environment.
	However, one potential approach is described below.		However, one potential approach is described below.
	</t>		</t>
	<t>		<t>
	When the client receives NFS4ERR_NO_GRACE, it could examine the change		When the client receives NFS4ERR_NO_GRACE, it could examine the change
	attribute of the objects for which the client is trying to reclaim stat e,		attribute of the objects for which the client is trying to reclaim stat e,
	and use that to determine whether to re-establish the state via normal		and use that to determine whether to re-establish the state via normal
	OPEN or LOCK operations. This is acceptable provided that the client's		OPEN or LOCK operations. This is acceptable provided that the client's
	operating environment allows it. In other words, the client		operating environment allows it. In other words, the client
	implementor is advised to document for his users the behavior. The		implementor is advised to document for his users the behavior. The
	client could also inform the application that its byte-range lock or sha re		client could also inform the application that its byte-range lock or sha re
	reservations (whether or not they were delegated) have been lost, such		reservations (whether or not they were delegated) have been lost, such
	as via a UNIX signal, a Graphical User Interface (GUI) pop-up window, et c.		as via a UNIX signal, a Graphical User Interface (GUI) pop-up window, et c.
	See <xref target="data_caching_revocation" />		See <xref target="data_caching_revocation" format="default"/>
	for a discussion of what the client should do		for a discussion of what the client should do
	for dealing with unreclaimed delegations on client state.		for dealing with unreclaimed delegations on client state.
	</t>		</t>
	<t>		<t>
	For further discussion of revocation of locks, see		For further discussion of revocation of locks, see
	<xref target="server_revocation" />.		<xref target="server_revocation" format="default"/>.
	</t>		</t>
	</section> <!-- "Network Partitions and Recovery" -->		</section>
	</section> <!-- "Crash Recovery" -->		</section>
	<section anchor="server_revocation" title="Server Revocation of Locks" >		<section anchor="server_revocation" numbered="true" toc="default">
	<t>		<name>Server Revocation of Locks</name>
			<t>
	At any point, the server can revoke locks held by a client, and the		At any point, the server can revoke locks held by a client, and the
	client must be prepared for this event. When the client detects that		client must be prepared for this event. When the client detects that
	its locks have been or may have been revoked, the client is		its locks have been or may have been revoked, the client is
	responsible for validating the state information between itself and		responsible for validating the state information between itself and
	the server. Validating locking state for the client means that it		the server. Validating locking state for the client means that it
	must verify or reclaim state for each lock currently held.		must verify or reclaim state for each lock currently held.
	</t>		</t>
	<t>		<t>
	The first occasion of lock revocation is upon server		The first occasion of lock revocation is upon server
	restart. Note that this includes situations		restart. Note that this includes situations
	in which sessions are persistent and locking state is		in which sessions are persistent and locking state is
	lost. In this class of instances, the client will		lost. In this class of instances, the client will
	receive an error (NFS4ERR_STALE_CLIENTID) on an		receive an error (NFS4ERR_STALE_CLIENTID) on an
	operation that takes client ID, usually as part of		operation that takes client ID, usually as part of
	recovery in response to a problem with the current		recovery in response to a problem with the current
	session), and the client will proceed		session), and the client will proceed
	with normal crash recovery as described in the <xref		with normal crash recovery as described in the <xref target="reclaim_locks
	target="reclaim_locks" />.		" format="default"/>.
	</t>		</t>
	<t>		<t>
	The second occasion of lock revocation is the inability to renew the lease		The second occasion of lock revocation is the inability to renew the lease
	before expiration, as discussed in		before expiration, as discussed in
	<xref target="network_partitions_and_recovery" />. While this is		<xref target="network_partitions_and_recovery" format="default"/>. While t his is
	considered a rare or unusual event,		considered a rare or unusual event,
	the client must be prepared to recover. The server is responsible		the client must be prepared to recover. The server is responsible
	for determining the precise consequences of the lease expiration,		for determining the precise consequences of the lease expiration,
	informing the client of the scope of the lock revocation decided		informing the client of the scope of the lock revocation decided
	upon. The client then uses the status information provided		upon. The client then uses the status information provided
	by the server in the SEQUENCE results (field sr_status_flags,		by the server in the SEQUENCE results (field sr_status_flags,
	see <xref target="OP_SEQUENCE_DESCRIPTION" />)		see <xref target="OP_SEQUENCE_DESCRIPTION" format="default"/>)
	to synchronize its locking state with that of the		to synchronize its locking state with that of the
	server, in order to recover.		server, in order to recover.
	</t>		</t>
	<t>		<t>
	The third occasion of lock revocation can occur as a result of		The third occasion of lock revocation can occur as a result of
	revocation of locks within the lease period, either because of		revocation of locks within the lease period, either because of
	administrative intervention or because a recallable lock (a		administrative intervention or because a recallable lock (a
	delegation or layout) was not returned within the lease period		delegation or layout) was not returned within the lease period
	after having been recalled. While these are		after having been recalled. While these are
	considered rare events, they are possible, and the client must be		considered rare events, they are possible, and the client must be
	prepared to deal with them. When either of these events occurs,		prepared to deal with them. When either of these events occurs,
	the client finds out about the situation through the status returned		the client finds out about the situation through the status returned
	by the SEQUENCE operation. Any use of stateids associated with		by the SEQUENCE operation. Any use of stateids associated with
	locks revoked during the lease period will receive the error		locks revoked during the lease period will receive the error
	NFS4ERR_ADMIN_REVOKED or NFS4ERR_DELEG_REVOKED, as appropriate.		NFS4ERR_ADMIN_REVOKED or NFS4ERR_DELEG_REVOKED, as appropriate.
	</t>		</t>
	<t>		<t>
	In all situations in which a subset of locking state may have been		In all situations in which a subset of locking state may have been
	revoked, which include all cases in which locking state is revoked		revoked, which include all cases in which locking state is revoked
	within the lease period, it is up to the client to determine which		within the lease period, it is up to the client to determine which
	locks have been revoked and which have not. It does this by		locks have been revoked and which have not. It does this by
	using the TEST_STATEID operation on the appropriate set of stateids.		using the TEST_STATEID operation on the appropriate set of stateids.
	Once the set of revoked locks has been determined, the applications		Once the set of revoked locks has been determined, the applications
	can be notified, and the invalidated stateids can be freed and		can be notified, and the invalidated stateids can be freed and
	lock revocation acknowledged by using FREE_STATEID.		lock revocation acknowledged by using FREE_STATEID.
	</t>		</t>
	</section> <!-- "Server Revocation of Locks" -->		</section>
	<section title="Short and Long Leases" >		<section numbered="true" toc="default">
	<t>		<name>Short and Long Leases</name>
			<t>
	When determining the time period for the server lease, the usual lease		When determining the time period for the server lease, the usual lease
	tradeoffs apply. A short lease is good for fast server recovery at a		trade-offs apply. A short lease is good for fast server recovery at a
	cost of increased operations to effect lease renewal (when there are		cost of increased operations to effect lease renewal (when there are
	no other operations during the period to effect lease renewal as a		no other operations during the period to effect lease renewal as a
	side effect). A long lease is certainly kinder and gentler to		side effect). A long lease is certainly kinder and gentler to
	servers trying to handle very large numbers of clients. The number of ext ra requests		servers trying to handle very large numbers of clients. The number of ext ra requests
	to effect lock renewal drops in inverse		to effect lock renewal drops in inverse
	proportion to the lease time. The disadvantages of a long lease		proportion to the lease time. The disadvantages of a long lease
	include the possibility of slower recovery after certain failures.		include the possibility of slower recovery after certain failures.
	After server failure, a longer grace period may be required when		After server failure, a longer grace period may be required when
	some clients do not promptly reclaim their locks and do a		some clients do not promptly reclaim their locks and do a
	global RECLAIM_COMPLETE. In the event of client failure,		global RECLAIM_COMPLETE. In the event of client failure,
	the longer period for a lease to expire will force conflicting		the longer period for a lease to expire will force conflicting
	requests to wait longer.		requests to wait longer.
	</t>		</t>
	<t>		<t>
	A long lease is practical if the server can store lease state in		A long lease is practical if the server can store lease state in
	stable storage. Upon recovery, the server can reconstruct the		stable storage. Upon recovery, the server can reconstruct the
	lease state from its stable storage and continue operation with		lease state from its stable storage and continue operation with
	its clients.		its clients.
	</t>		</t>
	</section> <!-- "Short and Long Leases" -->		</section>
	<section anchor="lease_propagation_delay" title="Clocks, Propagation Delay, an		<section anchor="lease_propagation_delay" numbered="true" toc="default">
	d Calculating Lease Expiration" >		<name>Clocks, Propagation Delay, and Calculating Lease Expiration</name>
	<t>		<t>
	To avoid the need for synchronized clocks, lease times are granted by		To avoid the need for synchronized clocks, lease times are granted by
	the server as a time delta. However, there is a requirement that the		the server as a time delta. However, there is a requirement that the
	client and server clocks do not drift excessively over the duration of		client and server clocks do not drift excessively over the duration of
	the lease. There is also the issue of propagation delay across the		the lease. There is also the issue of propagation delay across the
	network, which could easily be several hundred milliseconds, as well as		network, which could easily be several hundred milliseconds, as well as
	the possibility that requests will be lost and need to be		the possibility that requests will be lost and need to be
	retransmitted.		retransmitted.
	</t>		</t>
	<t>		<t>
	To take propagation delay into account, the client should		To take propagation delay into account, the client should
	subtract it from lease times (e.g., if the client estimates the		subtract it from lease times (e.g., if the client estimates the
	one-way propagation delay as 200 milliseconds, then it can		one-way propagation delay as 200 milliseconds, then it can
	assume that the lease is already 200 milliseconds old when it		assume that the lease is already 200 milliseconds old when it
	gets it). In addition, it will take another 200 milliseconds to		gets it). In addition, it will take another 200 milliseconds to
	get a response back to the server. So the client must send a		get a response back to the server. So the client must send a
	lease renewal or write data back to the server at least 400		lease renewal or write data back to the server at least 400
	milliseconds before the lease would expire. If the propagation delay		milliseconds before the lease would expire. If the propagation delay
	varies over the life of the lease (e.g., the client is on a mobile		varies over the life of the lease (e.g., the client is on a mobile
	host), the client will need to continuously subtract the increase		host), the client will need to continuously subtract the increase
	in propagation delay from the lease times.		in propagation delay from the lease times.
	</t>		</t>
	<t>		<t>
	The server's lease period configuration should take into account the		The server's lease period configuration should take into account the
	network distance of the clients that will be accessing the server's		network distance of the clients that will be accessing the server's
	resources. It is expected that the lease period will take into		resources. It is expected that the lease period will take into
	account the network propagation delays and other network delay factors		account the network propagation delays and other network delay factors
	for the client population. Since the protocol does not allow for an		for the client population. Since the protocol does not allow for an
	automatic method to determine an appropriate lease period, the		automatic method to determine an appropriate lease period, the
	server's administrator may have to tune the lease period.		server's administrator may have to tune the lease period.
	</t>		</t>
	</section> <!-- "Clocks, Propagation Delay, and Calculating Lease Expiration"		</section>
	-->		<section anchor="vestigial_locking" numbered="true" toc="default">
	<section title="Obsolete Locking Infrastructure from NFSv4.0" anchor="vestigia		<name>Obsolete Locking Infrastructure from NFSv4.0</name>
	l_locking" >		<t>
	<t>
	There are a number of operations and fields within existing		There are a number of operations and fields within existing
	operations that no longer have a function in NFSv4.1.		operations that no longer have a function in NFSv4.1.
	In one way or another, these changes are all due to		In one way or another, these changes are all due to
	the implementation of sessions that provide client context		the implementation of sessions that provide client context
	and exactly once semantics as a base feature of the protocol,		and exactly once semantics as a base feature of the protocol,
	separate from locking itself.		separate from locking itself.
	</t>		</t>
	<t>
	The following NFSv4.0 operations MUST NOT be implemented in NFSv4.1.
	The server MUST return NFS4ERR_NOTSUPP if these operations are
	found in an NFSv4.1 COMPOUND.
	<list style='symbols'>
	<t>		<t>
			The following NFSv4.0 operations <bcp14>MUST NOT</bcp14> be implemented in
			NFSv4.1.
			The server <bcp14>MUST</bcp14> return NFS4ERR_NOTSUPP if these operations
			are
			found in an NFSv4.1 COMPOUND.
			</t>
			<ul spacing="normal">
			<li>
	SETCLIENTID since its function has been replaced by		SETCLIENTID since its function has been replaced by
	EXCHANGE_ID.		EXCHANGE_ID.
	</t>		</li>
	<t>		<li>
	SETCLIENTID_CONFIRM since client ID confirmation now		SETCLIENTID_CONFIRM since client ID confirmation now
	happens by means of CREATE_SESSION.		happens by means of CREATE_SESSION.
	</t>		</li>
	<t>		<li>
	OPEN_CONFIRM because state-owner-based seqids		OPEN_CONFIRM because state-owner-based seqids
	have been replaced by the sequence ID in the		have been replaced by the sequence ID in the
	SEQUENCE operation.		SEQUENCE operation.
	</t>		</li>
	<t>		<li>
	RELEASE_LOCKOWNER because lock-owners with no associated		RELEASE_LOCKOWNER because lock-owners with no associated
	locks do not have any sequence-related state and so can		locks do not have any sequence-related state and so can
	be deleted by the server at will.		be deleted by the server at will.
	</t>		</li>
	<t>		<li>
	RENEW because every SEQUENCE operation for a session causes		RENEW because every SEQUENCE operation for a session causes
	lease renewal, making a separate operation superfluous.		lease renewal, making a separate operation superfluous.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Also, there are a number of fields, present in existing operations,		Also, there are a number of fields, present in existing operations,
	related to locking that have no use in minor version 1. They		related to locking that have no use in minor version 1. They
	were used in minor version 0 to perform functions now provided		were used in minor version 0 to perform functions now provided
	in a different		in a different
	fashion.		fashion.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	Sequence ids used to sequence requests for a given state-owner		Sequence ids used to sequence requests for a given state-owner
	and to provide retry protection, now provided		and to provide retry protection, now provided
	via sessions.		via sessions.
	</t>		</li>
	<t>		<li>
	Client IDs used to identify the client associated with a given		Client IDs used to identify the client associated with a given
	request. Client identification is now available using the client ID		request. Client identification is now available using the client ID
	associated with the current session, without needing an explicit		associated with the current session, without needing an explicit
	client ID field.		client ID field.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Such vestigial fields in existing operations have no function in		Such vestigial fields in existing operations have no function in
	NFSv4.1 and are ignored by the server. Note that client IDs in		NFSv4.1 and are ignored by the server. Note that client IDs in
	operations new to NFSv4.1 (such as CREATE_SESSION and DESTROY_CLIENTID)		operations new to NFSv4.1 (such as CREATE_SESSION and DESTROY_CLIENTID)
	are not ignored.		are not ignored.
	</t>		</t>
	</section> <!-- "Vestigial Locking Infrastructure From V4.0" -->		</section>
	</section> <!-- "State Management" -->		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp $
	-->
	<!-- Copyright (C) The IETF Trust (2007-2008) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section title="File Locking and Share Reservations" anchor="file_locking">		<section anchor="file_locking" numbered="true" toc="default">
	<t>		<name>File Locking and Share Reservations</name>
			<t>
	To support Win32 share reservations, it is necessary to provide		To support Win32 share reservations, it is necessary to provide
	operations that atomically open or create files. Having a		operations that atomically open or create files. Having a
	separate share/unshare operation would not allow correct		separate share/unshare operation would not allow correct
	implementation of the Win32 OpenFile API. In order to		implementation of the Win32 OpenFile API. In order to
	correctly implement share semantics, the previous NFS protocol		correctly implement share semantics, the previous NFS protocol
	mechanisms used when a file is opened or created (LOOKUP, CREATE,		mechanisms used when a file is opened or created (LOOKUP, CREATE,
	ACCESS) need to be replaced. The NFSv4.1 protocol defines		ACCESS) need to be replaced. The NFSv4.1 protocol defines
	an OPEN operation that is capable of atomically looking up, creating,		an OPEN operation that is capable of atomically looking up, creating,
	and locking a file on the server.		and locking a file on the server.
	</t>		</t>
	<section title="Opens and Byte-Range Locks" >		<section numbered="true" toc="default">
	<t>		<name>Opens and Byte-Range Locks</name>
			<t>
	It is assumed that manipulating a byte-range lock is rare when		It is assumed that manipulating a byte-range lock is rare when
	compared to READ		compared to READ
	and WRITE operations. It is also assumed that server restarts and network		and WRITE operations. It is also assumed that server restarts and network
	partitions are relatively rare. Therefore, it is important that the		partitions are relatively rare. Therefore, it is important that the
	READ and WRITE operations have a lightweight mechanism to indicate if		READ and WRITE operations have a lightweight mechanism to indicate if
	they possess a held lock. A LOCK operation contains the		they possess a held lock. A LOCK operation contains the
	heavyweight information required to establish a byte-range lock and unique ly		heavyweight information required to establish a byte-range lock and unique ly
	define the owner of the lock.		define the owner of the lock.
	</t>		</t>
	<section anchor="state-owner" title="State-Owner Definition" >		<section anchor="state-owner" numbered="true" toc="default">
	<t>		<name>State-Owner Definition</name>
			<t>
	When opening a file or requesting a byte-range lock, the		When opening a file or requesting a byte-range lock, the
	client must specify an identifier that represents the owner of		client must specify an identifier that represents the owner of
	the requested lock. This identifier is in the form of a		the requested lock. This identifier is in the form of a
	state-owner, represented in the protocol by a state_owner4, a		state-owner, represented in the protocol by a state_owner4, a
	variable-length opaque array that, when concatenated with the		variable-length opaque array that, when concatenated with the
	current client ID, uniquely defines the owner of a lock managed		current client ID, uniquely defines the owner of a lock managed
	by the client. This may be a thread ID, process ID, or other		by the client. This may be a thread ID, process ID, or other
	unique value.		unique value.
	</t>		</t>
	<t>		<t>
	Owners of opens and owners of byte-range locks are separate		Owners of opens and owners of byte-range locks are separate
	entities and remain separate even if the same opaque arrays		entities and remain separate even if the same opaque arrays
	are used to designate owners of each. The protocol distinguishes		are used to designate owners of each. The protocol distinguishes
	between open-owners (represented by open_owner4 structures)		between open-owners (represented by open_owner4 structures)
	and lock-owners (represented by lock_owner4 structures).		and lock-owners (represented by lock_owner4 structures).
	</t>		</t>
	<t>		<t>
	Each open is associated with a specific open-owner while each		Each open is associated with a specific open-owner while each
	byte-range lock is associated with a lock-owner and an		byte-range lock is associated with a lock-owner and an
	open-owner, the latter being the open-owner associated with the		open-owner, the latter being the open-owner associated with the
	open file under which the LOCK operation was done. Delegations		open file under which the LOCK operation was done. Delegations
	and layouts, on the other hand, are not associated with a		and layouts, on the other hand, are not associated with a
	specific owner but are associated with the client as a whole		specific owner but are associated with the client as a whole
	(identified by a client ID).		(identified by a client ID).
	</t>		</t>
	</section> <!-- "State-owner Definition" -->		</section>
	<section title="Use of the Stateid and Locking" >		<section numbered="true" toc="default">
	<t>		<name>Use of the Stateid and Locking</name>
			<t>
	All READ, WRITE, and SETATTR operations contain a stateid. For the		All READ, WRITE, and SETATTR operations contain a stateid. For the
	purposes of this section, SETATTR operations that change the size		purposes of this section, SETATTR operations that change the size
	attribute of a file are treated as if they are writing the area		attribute of a file are treated as if they are writing the area
	between the old and new sizes (i.e., the byte-range truncated or added t o the		between the old and new sizes (i.e., the byte-range truncated or added t o the
	file by means of the SETATTR), even where SETATTR is not explicitly		file by means of the SETATTR), even where SETATTR is not explicitly
	mentioned in the text. The stateid passed to one of these operations mu st		mentioned in the text. The stateid passed to one of these operations mu st
	be one that represents an open, a set of byte-range locks, or a		be one that represents an open, a set of byte-range locks, or a
	delegation, or it may be a special stateid representing anonymous		delegation, or it may be a special stateid representing anonymous
	access or the special bypass stateid.		access or the special bypass stateid.
	</t>		</t>
	<t>		<t>
	If the state-owner performs a READ or WRITE operation in a situation in which		If the state-owner performs a READ or WRITE operation in a situation in which
	it has established a byte-range lock or share reservation		it has established a byte-range lock or share reservation
	on the server (any OPEN constitutes a share reservation), the		on the server (any OPEN constitutes a share reservation), the
	stateid (previously returned by the server) must be used to		stateid (previously returned by the server) must be used to
	indicate what locks, including both byte-range		indicate what locks, including both byte-range
	locks and share reservations, are held by the state-owner. If no state		locks and share reservations, are held by the state-owner. If no state
	is established by the client, either a byte-range lock or a share reserv ation,		is established by the client, either a byte-range lock or a share reserv ation,
	a special stateid for anonymous state (zero as the value for "other" and "seqid")		a special stateid for anonymous state (zero as the value for "other" and "seqid")
	is used. (See <xref target='special_stateid' /> for a description of		is used. (See <xref target="special_stateid" format="default"/> for a d escription of
	'special' stateids in general.)		'special' stateids in general.)
	Regardless of whether a stateid for anonymous state		Regardless of whether a stateid for anonymous state
	or a stateid returned by the server is used, if there is a		or a stateid returned by the server is used, if there is a
	conflicting share reservation or mandatory byte-range lock held on the		conflicting share reservation or mandatory byte-range lock held on the
	file, the server MUST refuse to service the READ or WRITE operation.		file, the server <bcp14>MUST</bcp14> refuse to service the READ or WRITE
	</t>		operation.
	<t>		</t>
			<t>
	Share reservations are established by OPEN operations and by their		Share reservations are established by OPEN operations and by their
	nature are mandatory in that when the OPEN denies READ or WRITE		nature are mandatory in that when the OPEN denies READ or WRITE
	operations, that denial results in such operations being rejected with		operations, that denial results in such operations being rejected with
	error NFS4ERR_LOCKED. Byte-range locks may be implemented by the server		error NFS4ERR_LOCKED. Byte-range locks may be implemented by the server
	as either mandatory or advisory, or the choice of mandatory or		as either mandatory or advisory, or the choice of mandatory or
	advisory behavior may be determined by the server on the basis of the		advisory behavior may be determined by the server on the basis of the
	file being accessed (for example, some UNIX-based servers support a		file being accessed (for example, some UNIX-based servers support a
	"mandatory lock bit" on the mode attribute such that if set, byte-range		"mandatory lock bit" on the mode attribute such that if set, byte-range
	locks are required on the file before I/O is possible). When byte-range		locks are required on the file before I/O is possible). When byte-range
	locks are advisory, they only prevent the granting of conflicting lock		locks are advisory, they only prevent the granting of conflicting lock
	requests and have no effect on READs or WRITEs. Mandatory byte-range		requests and have no effect on READs or WRITEs. Mandatory byte-range
	locks, however, prevent conflicting I/O operations. When they are		locks, however, prevent conflicting I/O operations. When they are
	attempted, they are rejected with NFS4ERR_LOCKED. When the client		attempted, they are rejected with NFS4ERR_LOCKED. When the client
	gets NFS4ERR_LOCKED on a file for which it knows it has the proper share		gets NFS4ERR_LOCKED on a file for which it knows it has the proper share
	reservation, it will need to send a LOCK operation on the byte-range of		reservation, it will need to send a LOCK operation on the byte-range of
	the file that includes the byte-range the I/O was to be performed on, wi th		the file that includes the byte-range the I/O was to be performed on, wi th
	an appropriate locktype field of the LOCK operation's arguments (i.e., R EAD*_LT for a READ operation, WRITE*_LT		an appropriate locktype field of the LOCK operation's arguments (i.e., R EAD*_LT for a READ operation, WRITE*_LT
	for a WRITE operation).		for a WRITE operation).
	</t>		</t>
	<t>		<t>
	Note that for UNIX environments that support mandatory byte-range lockin g,		Note that for UNIX environments that support mandatory byte-range lockin g,
	the distinction between advisory and mandatory locking is subtle. In		the distinction between advisory and mandatory locking is subtle. In
	fact, advisory and mandatory byte-range locks are exactly the same as		fact, advisory and mandatory byte-range locks are exactly the same as
	far as the APIs and requirements on implementation. If the mandatory		far as the APIs and requirements on implementation. If the mandatory
	lock attribute is set on the file, the server checks to see if the		lock attribute is set on the file, the server checks to see if the
	lock-owner has an appropriate shared (READ_LT) or exclusive (WRITE_LT) b yte-range		lock-owner has an appropriate shared (READ_LT) or exclusive (WRITE_LT) b yte-range
	lock on the byte-range it wishes to READ from or WRITE to. If there is n o		lock on the byte-range it wishes to READ from or WRITE to. If there is n o
	appropriate lock, the server checks if there is a conflicting lock		appropriate lock, the server checks if there is a conflicting lock
	(which can be done by attempting to acquire the conflicting lock on		(which can be done by attempting to acquire the conflicting lock on
	behalf of the lock-owner, and if successful, release the lock after		behalf of the lock-owner, and if successful, release the lock after
	the READ or WRITE operation is done), and if there is, the server return s		the READ or WRITE operation is done), and if there is, the server return s
	NFS4ERR_LOCKED.		NFS4ERR_LOCKED.
	</t>		</t>
	<t>		<t>
	For Windows environments, byte-range locks are always mandatory, so the		For Windows environments, byte-range locks are always mandatory, so the
	server always checks for byte-range locks during I/O requests.		server always checks for byte-range locks during I/O requests.
	</t>		</t>
	<t>		<t>
	Thus, the LOCK operation does not need to distinguish		Thus, the LOCK operation does not need to distinguish
	between advisory and mandatory byte-range locks. It is the		between advisory and mandatory byte-range locks. It is the
	server's processing of the READ and WRITE operations that introduces		server's processing of the READ and WRITE operations that introduces
	the distinction.		the distinction.
	</t>		</t>
	<t>		<t>
	Every stateid that is validly passed to READ, WRITE, or SETATTR,		Every stateid that is validly passed to READ, WRITE, or SETATTR,
	with the exception of special stateid values,		with the exception of special stateid values,
	defines an access mode for the file (i.e.,		defines an access mode for the file (i.e.,
	OPEN4_SHARE_ACCESS_READ, OPEN4_SHARE_ACCESS_WRITE, or		OPEN4_SHARE_ACCESS_READ, OPEN4_SHARE_ACCESS_WRITE, or
	OPEN4_SHARE_ACCESS_BOTH).		OPEN4_SHARE_ACCESS_BOTH).
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	For stateids associated with opens, this is the mode defined by		For stateids associated with opens, this is the mode defined by
	the original OPEN that caused the		the original OPEN that caused the
	allocation of the OPEN stateid		allocation of the OPEN stateid
	and as modified by subsequent OPENs and OPEN_DOWNGRADEs for the		and as modified by subsequent OPENs and OPEN_DOWNGRADEs for the
	same open-owner/file pair.		same open-owner/file pair.
	</t>		</li>
	<t>		<li>
	For stateids returned by byte-range LOCK operations,		For stateids returned by byte-range LOCK operations,
	the appropriate mode is the access mode for the OPEN		the appropriate mode is the access mode for the OPEN
	stateid associated with the lock set represented by the stateid.		stateid associated with the lock set represented by the stateid.
	</t>		</li>
	<t>		<li>
	For delegation stateids, the access mode is based on the type of del egation.		For delegation stateids, the access mode is based on the type of del egation.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	When a READ, WRITE, or SETATTR (that specifies the		When a READ, WRITE, or SETATTR (that specifies the
	size attribute) operation is done, the operation is subject to checking against		size attribute) operation is done, the operation is subject to checking against
	the access mode to verify that the operation is appropriate given the		the access mode to verify that the operation is appropriate given the
	stateid with which the operation is associated.		stateid with which the operation is associated.
	</t>		</t>
	<t>		<t>
	In the case of WRITE-type operations (i.e., WRITEs and SETATTRs that		In the case of WRITE-type operations (i.e., WRITEs and SETATTRs that
	set size), the server MUST verify that the access mode allows writing		set size), the server <bcp14>MUST</bcp14> verify that the access mode al
	and MUST return an NFS4ERR_OPENMODE error if it does not. In the case o		lows writing
	f		and <bcp14>MUST</bcp14> return an NFS4ERR_OPENMODE error if it does not.
			In the case of
	READ, the server may perform the corresponding check on the access		READ, the server may perform the corresponding check on the access
	mode, or it may choose to allow READ on OPENs for OPEN4_SHARE_ACCESS_WRI TE, to		mode, or it may choose to allow READ on OPENs for OPEN4_SHARE_ACCESS_WRI TE, to
	accommodate clients whose WRITE implementation may unavoidably do		accommodate clients whose WRITE implementation may unavoidably do
	reads (e.g., due to buffer cache constraints). However, even if READs		reads (e.g., due to buffer cache constraints). However, even if READs
	are allowed in these circumstances, the server MUST still check for		are allowed in these circumstances, the server <bcp14>MUST</bcp14> still check for
	locks that conflict with the READ (e.g., another OPEN specified OPEN4_SH ARE_DENY_READ or OPEN4_SHARE_DENY_BOTH). Note that a server that does enforce t he access mode check		locks that conflict with the READ (e.g., another OPEN specified OPEN4_SH ARE_DENY_READ or OPEN4_SHARE_DENY_BOTH). Note that a server that does enforce t he access mode check
	on READs need not explicitly check for conflicting share reservations		on READs need not explicitly check for conflicting share reservations
	since the existence of OPEN for OPEN4_SHARE_ACCESS_READ guarantees that no		since the existence of OPEN for OPEN4_SHARE_ACCESS_READ guarantees that no
	conflicting share reservation can exist.		conflicting share reservation can exist.
	</t>		</t>
	<t>		<t>
	The READ bypass special stateid (all bits of "other" and "seqid" set		The READ bypass special stateid (all bits of "other" and "seqid" set
	to one)		to one)
	indicates a desire to bypass locking checks. The server MAY		indicates a desire to bypass locking checks. The server <bcp14>MAY</bcp 14>
	allow READ operations to bypass		allow READ operations to bypass
	locking checks at the server, when this special stateid is used.		locking checks at the server, when this special stateid is used.
	However, WRITE operations with		However, WRITE operations with
	this special stateid value MUST NOT bypass locking checks and are		this special stateid value <bcp14>MUST NOT</bcp14> bypass locking checks and are
	treated exactly the same as if a special stateid for anonymous state		treated exactly the same as if a special stateid for anonymous state
	were used.		were used.
	</t>		</t>
	<t>		<t>
	A lock may not be granted while a READ or WRITE operation using one of		A lock may not be granted while a READ or WRITE operation using one of
	the special stateids is being performed and the scope of the lock		the special stateids is being performed and the scope of the lock
	to be granted would conflict with the READ or WRITE operation.		to be granted would conflict with the READ or WRITE operation.
	This can occur when:		This can occur when:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	A mandatory byte-range lock is requested with a byte-range that		A mandatory byte-range lock is requested with a byte-range that
	conflicts with the byte-range of the READ or WRITE operation.		conflicts with the byte-range of the READ or WRITE operation.
	For the purposes of this paragraph, a conflict occurs when		For the purposes of this paragraph, a conflict occurs when
	a shared lock is requested and a WRITE operation is being		a shared lock is requested and a WRITE operation is being
	performed, or an exclusive lock is requested and either a		performed, or an exclusive lock is requested and either a
	READ or a WRITE operation is being performed.		READ or a WRITE operation is being performed.
	</t>		</li>
	<t>		<li>
	A share reservation is requested that denies reading and/or		A share reservation is requested that denies reading and/or
	writing and the corresponding operation is being performed.		writing and the corresponding operation is being performed.
	</t>		</li>
	<t>		<li>
	A delegation is to be granted and the delegation type would		A delegation is to be granted and the delegation type would
	prevent the I/O operation, i.e., READ and WRITE conflict with		prevent the I/O operation, i.e., READ and WRITE conflict with
	an OPEN_DELEGATE_WRITE delegation and WRITE conflicts with an OPEN_D ELEGATE_READ delegation.		an OPEN_DELEGATE_WRITE delegation and WRITE conflicts with an OPEN_D ELEGATE_READ delegation.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	When a client holds a delegation, it needs to ensure		When a client holds a delegation, it needs to ensure
	that the stateid sent conveys the association of		that the stateid sent conveys the association of
	operation with the delegation, to avoid the delegation from		operation with the delegation, to avoid the delegation from
	being avoidably recalled. When the delegation stateid,		being avoidably recalled. When the delegation stateid,
	a stateid open associated with that delegation, or a stateid		a stateid open associated with that delegation, or a stateid
	representing byte-range locks derived from such an open is		representing byte-range locks derived from such an open is
	used, the server knows that the READ, WRITE, or SETATTR		used, the server knows that the READ, WRITE, or SETATTR
	does not conflict with the delegation but is sent under		does not conflict with the delegation but is sent under
	the aegis of the delegation. Even though it is possible		the aegis of the delegation. Even though it is possible
	for the server to determine from the client ID (via		for the server to determine from the client ID (via
	the session ID) that the client does in fact have a		the session ID) that the client does in fact have a
	delegation, the server is not obliged to check this, so		delegation, the server is not obliged to check this, so
	using a special stateid can result in avoidable recall		using a special stateid can result in avoidable recall
	of the delegation.		of the delegation.
	</t>		</t>
	</section> <!-- "Use of the Stateid and Locking" -->		</section>
	</section> <!-- "Opens and Byte-Range Locks" -->		</section>
	<section title="Lock Ranges" >		<section numbered="true" toc="default">
	<t>		<name>Lock Ranges</name>
			<t>
	The protocol allows a lock-owner to request a lock with a byte-range		The protocol allows a lock-owner to request a lock with a byte-range
	and then either upgrade, downgrade, or unlock a sub-range of		and then either upgrade, downgrade, or unlock a sub-range of
	the initial lock, or a byte-range that		the initial lock, or a byte-range that
	overlaps -- fully or partially -- either with that initial lock or a		overlaps -- fully or partially -- either with that initial lock or a
	combination of a set of existing locks for the same lock-owner. It		combination of a set of existing locks for the same lock-owner. It
	is expected that this will be an uncommon type of request. In any		is expected that this will be an uncommon type of request. In any
	case, servers or server file systems may not be able to support		case, servers or server file systems may not be able to support
	sub-range lock semantics. In the event that a server receives a		sub-range lock semantics. In the event that a server receives a
	locking request that represents a sub-range of current locking state		locking request that represents a sub-range of current locking state
	for the lock-owner, the server is allowed to return the error		for the lock-owner, the server is allowed to return the error
	NFS4ERR_LOCK_RANGE to signify that it does not support sub-range lock		NFS4ERR_LOCK_RANGE to signify that it does not support sub-range lock
	operations. Therefore, the client should be prepared to receive this		operations. Therefore, the client should be prepared to receive this
	error and, if appropriate, report the error to the requesting		error and, if appropriate, report the error to the requesting
	application.		application.
	</t>		</t>
	<t>		<t>
	The client is discouraged from combining multiple independent locking		The client is discouraged from combining multiple independent locking
	ranges that happen to be adjacent into a single request since the		ranges that happen to be adjacent into a single request since the
	server may not support sub-range requests for reasons related to		server may not support sub-range requests for reasons related to
	the recovery of byte-range locking state in the event of server failure. As		the recovery of byte-range locking state in the event of server failure. As
	discussed in <xref target="server_failure" />, the		discussed in <xref target="server_failure" format="default"/>, the
	server may employ certain optimizations during recovery that work		server may employ certain optimizations during recovery that work
	effectively only when the client's behavior during lock recovery is		effectively only when the client's behavior during lock recovery is
	similar to the client's locking behavior prior to server failure.		similar to the client's locking behavior prior to server failure.
	</t>		</t>
	</section> <!-- "Lock Ranges" -->		</section>
	<section title="Upgrading and Downgrading Locks" >		<section numbered="true" toc="default">
	<t>		<name>Upgrading and Downgrading Locks</name>
			<t>
	If a client has a WRITE_LT lock on a byte-range, it can request an atomic		If a client has a WRITE_LT lock on a byte-range, it can request an atomic
	downgrade of the lock to a READ_LT lock via the LOCK operation, by setting		downgrade of the lock to a READ_LT lock via the LOCK operation, by setting
	the type to READ_LT. If the server supports atomic downgrade, the		the type to READ_LT. If the server supports atomic downgrade, the
	request will succeed. If not, it will return NFS4ERR_LOCK_NOTSUPP. The		request will succeed. If not, it will return NFS4ERR_LOCK_NOTSUPP. The
	client should be prepared to receive this error and, if appropriate,		client should be prepared to receive this error and, if appropriate,
	report the error to the requesting application.		report the error to the requesting application.
	</t>		</t>
	<t>		<t>
	If a client has a READ_LT lock on a byte-range, it can request an atomic		If a client has a READ_LT lock on a byte-range, it can request an atomic
	upgrade of the lock to a WRITE_LT lock via the LOCK operation by setting		upgrade of the lock to a WRITE_LT lock via the LOCK operation by setting
	the type to WRITE_LT or WRITEW_LT. If the server does not support		the type to WRITE_LT or WRITEW_LT. If the server does not support
	atomic upgrade, it will return NFS4ERR_LOCK_NOTSUPP. If the upgrade		atomic upgrade, it will return NFS4ERR_LOCK_NOTSUPP. If the upgrade
	can be achieved without an existing conflict, the request will		can be achieved without an existing conflict, the request will
	succeed. Otherwise, the server will return either NFS4ERR_DENIED or		succeed. Otherwise, the server will return either NFS4ERR_DENIED or
	NFS4ERR_DEADLOCK. The error NFS4ERR_DEADLOCK is returned if the client		NFS4ERR_DEADLOCK. The error NFS4ERR_DEADLOCK is returned if the client
	sent the LOCK operation with the type set to WRITEW_LT and the server		sent the LOCK operation with the type set to WRITEW_LT and the server
	has detected a deadlock. The client should be prepared to receive such		has detected a deadlock. The client should be prepared to receive such
	errors and, if appropriate, report the error to the requesting		errors and, if appropriate, report the error to the requesting
	application.		application.
	</t>		</t>
	</section> <!-- "Upgrading and Downgrading Locks" -->		</section>
	<section title="Stateid Seqid Values and Byte-Range Locks"		<section anchor="byte_range_seqid" numbered="true" toc="default">
	anchor="byte_range_seqid" >		<name>Stateid Seqid Values and Byte-Range Locks</name>
	<t>		<t>
	When a LOCK or LOCKU operation is performed,		When a LOCK or LOCKU operation is performed,
	the stateid returned has the same "other" value as the argument's		the stateid returned has the same "other" value as the argument's
	stateid, and a		stateid, and a
	"seqid" value that is incremented (relative to the argument's		"seqid" value that is incremented (relative to the argument's
	stateid) to reflect the occurrence		stateid) to reflect the occurrence
	of the LOCK or LOCKU operation. The server MUST increment		of the LOCK or LOCKU operation. The server <bcp14>MUST</bcp14> increment
	the value of the "seqid" field whenever there is any change		the value of the "seqid" field whenever there is any change
	to the locking status of any byte offset as described by		to the locking status of any byte offset as described by
	any of the locks covered by the stateid. A change in locking		any of the locks covered by the stateid. A change in locking
	status includes a change from locked to unlocked or the reverse or		status includes a change from locked to unlocked or the reverse or
	a change from being locked for READ_LT to being locked for WRITE_LT		a change from being locked for READ_LT to being locked for WRITE_LT
	or the reverse.		or the reverse.
	</t>		</t>
	<t>		<t>
	When there is no such change, as, for example, when a range		When there is no such change, as, for example, when a range
	already locked for WRITE_LT is locked again for WRITE_LT, the		already locked for WRITE_LT is locked again for WRITE_LT, the
	server MAY increment the "seqid" value.		server <bcp14>MAY</bcp14> increment the "seqid" value.
	</t>		</t>
	</section> <!-- "Stateid Sequence Values and Byte-Range Locks" -->		</section>
	<section title="Issues with Multiple Open-Owners"		<section anchor="multiple_openowners" numbered="true" toc="default">
	anchor="multiple_openowners" >		<name>Issues with Multiple Open-Owners</name>
	<t>		<t>
	When the same file is opened by multiple open-owners,		When the same file is opened by multiple open-owners,
	a client will have multiple OPEN stateids for that		a client will have multiple OPEN stateids for that
	file, each associated with a different open-owner.		file, each associated with a different open-owner.
	In that case, there can be multiple LOCK and LOCKU		In that case, there can be multiple LOCK and LOCKU
	requests for the same lock-owner sent using the		requests for the same lock-owner sent using the
	different OPEN stateids, and so a situation may		different OPEN stateids, and so a situation may
	arise in which there are multiple stateids, each		arise in which there are multiple stateids, each
	representing byte-range locks on the same file and		representing byte-range locks on the same file and
	held by the same lock-owner but each associated with		held by the same lock-owner but each associated with
	a different open-owner.		a different open-owner.
	</t>		</t>
	<t>		<t>
	In such a situation, the locking status of each byte		In such a situation, the locking status of each byte
	(i.e., whether it is locked, the READ_LT or WRITE_LT type of		(i.e., whether it is locked, the READ_LT or WRITE_LT type of
	the lock, and the lock-owner holding the lock) MUST		the lock, and the lock-owner holding the lock) <bcp14>MUST</bcp14>
	reflect the last LOCK or LOCKU operation done for the		reflect the last LOCK or LOCKU operation done for the
	lock-owner in question, independent of the stateid through		lock-owner in question, independent of the stateid through
	which the request was sent.		which the request was sent.
	</t>		</t>
	<t>		<t>
	When a byte is locked by the lock-owner in question, the		When a byte is locked by the lock-owner in question, the
	open-owner to which that byte-range lock is assigned SHOULD be that		open-owner to which that byte-range lock is assigned <bcp14>SHOULD</bcp14> be that
	of the open-owner associated with the stateid through		of the open-owner associated with the stateid through
	which the last LOCK of that byte was done. When there		which the last LOCK of that byte was done. When there
	is a change in the open-owner associated with locks for		is a change in the open-owner associated with locks for
	the stateid through which a LOCK or LOCKU was done, the		the stateid through which a LOCK or LOCKU was done, the
	"seqid" field of the stateid MUST be incremented, even		"seqid" field of the stateid <bcp14>MUST</bcp14> be incremented, even
	if the locking, in terms of lock-owners has not changed.		if the locking, in terms of lock-owners has not changed.
	When there is a change to the set of locked bytes associated		When there is a change to the set of locked bytes associated
	with a different stateid for the same lock-owner, i.e.,		with a different stateid for the same lock-owner, i.e.,
	associated with a different open-owner, the "seqid" value		associated with a different open-owner, the "seqid" value
	for that stateid MUST NOT be incremented.		for that stateid <bcp14>MUST NOT</bcp14> be incremented.
	</t>		</t>
	</section> <!-- "Issues with Multiple Open-Owners" -->		</section>
	<section title="Blocking Locks" anchor="blocking_locks" >		<section anchor="blocking_locks" numbered="true" toc="default">
	<t>		<name>Blocking Locks</name>
			<t>
	Some clients require the support of blocking locks. While NFSv4.1		Some clients require the support of blocking locks. While NFSv4.1
	provides a callback when a previously unavailable lock becomes		provides a callback when a previously unavailable lock becomes
	available, this is an OPTIONAL feature and clients cannot		available, this is an <bcp14>OPTIONAL</bcp14> feature and clients cannot
	depend on its presence. Clients need to be prepared to continually		depend on its presence. Clients need to be prepared to continually
	poll for the lock. This presents a fairness problem. Two of		poll for the lock. This presents a fairness problem. Two of
	the lock types, READW_LT and WRITEW_LT, are used to indicate to the		the lock types, READW_LT and WRITEW_LT, are used to indicate to the
	server that the client is requesting a blocking lock. When the		server that the client is requesting a blocking lock. When the
	callback is not used, the server should maintain an ordered		callback is not used, the server should maintain an ordered
	list of pending blocking locks. When the conflicting lock is		list of pending blocking locks. When the conflicting lock is
	released, the server may wait for the period of time equal to		released, the server may wait for the period of time equal to
	lease_time for the first waiting		lease_time for the first waiting
	client to re-request the lock. After the lease period expires, the		client to re-request the lock. After the lease period expires, the
	next waiting client request is allowed the lock. Clients are required		next waiting client request is allowed the lock. Clients are required
	to poll at an interval sufficiently small that it is likely to acquire		to poll at an interval sufficiently small that it is likely to acquire
	the lock in a timely manner. The server is not required to maintain a		the lock in a timely manner. The server is not required to maintain a
	list of pending blocked locks as it is used to increase fairness and		list of pending blocked locks as it is used to increase fairness and
	not correct operation. Because of the unordered nature of crash		not correct operation. Because of the unordered nature of crash
	recovery, storing of lock state to stable storage would be required to		recovery, storing of lock state to stable storage would be required to
	guarantee ordered granting of blocking locks.		guarantee ordered granting of blocking locks.
	</t>		</t>
	<t>		<t>
	Servers may also note the lock types and delay returning denial of the		Servers may also note the lock types and delay returning denial of the
	request to allow extra time for a conflicting lock to be released,		request to allow extra time for a conflicting lock to be released,
	allowing a successful return. In this way, clients can avoid the		allowing a successful return. In this way, clients can avoid the
	burden of needless frequent polling for blocking locks. The server		burden of needless frequent polling for blocking locks. The server
	should take care in the length of delay in the event the client		should take care in the length of delay in the event the client
	retransmits the request.		retransmits the request.
	</t>		</t>
	<t>		<t>
	If a server receives a blocking LOCK operation, denies it, and then		If a server receives a blocking LOCK operation, denies it, and then
	later receives a nonblocking request for the same lock, which is		later receives a nonblocking request for the same lock, which is
	also denied, then it should remove the lock in question from its list of		also denied, then it should remove the lock in question from its list of
	pending blocking locks. Clients should use such a nonblocking request		pending blocking locks. Clients should use such a nonblocking request
	to indicate to the server that this is the last time they intend to poll		to indicate to the server that this is the last time they intend to poll
	for the lock, as may happen when the process requesting the lock is		for the lock, as may happen when the process requesting the lock is
	interrupted. This is a courtesy to the server, to prevent it from		interrupted. This is a courtesy to the server, to prevent it from
	unnecessarily waiting a lease period before granting other LOCK operations .		unnecessarily waiting a lease period before granting other LOCK operations .
	However, clients are not required to perform this courtesy, and servers		However, clients are not required to perform this courtesy, and servers
	must not depend on them doing so. Also, clients must be prepared for		must not depend on them doing so. Also, clients must be prepared for
	the possibility that this final locking request will be accepted.		the possibility that this final locking request will be accepted.
	</t>		</t>
	<t>		<t>
	When a server indicates, via the flag OPEN4_RESULT_MAY_NOTIFY_LOCK, that		When a server indicates, via the flag OPEN4_RESULT_MAY_NOTIFY_LOCK, that
	CB_NOTIFY_LOCK callbacks might be done for the current open file, the		CB_NOTIFY_LOCK callbacks might be done for the current open file, the
	client should take notice of this, but, since this is a hint, cannot		client should take notice of this, but, since this is a hint, cannot
	rely on a CB_NOTIFY_LOCK always being done. A client may reasonably		rely on a CB_NOTIFY_LOCK always being done. A client may reasonably
	reduce the frequency with which it polls for a denied lock, since the		reduce the frequency with which it polls for a denied lock, since the
	greater latency that might occur is likely to be eliminated given a		greater latency that might occur is likely to be eliminated given a
	prompt callback, but it still needs to poll. When it receives a		prompt callback, but it still needs to poll. When it receives a
	CB_NOTIFY_LOCK, it should promptly try to obtain the lock, but it		CB_NOTIFY_LOCK, it should promptly try to obtain the lock, but it
	should be aware that other clients may be polling and that the server is u nder		should be aware that other clients may be polling and that the server is u nder
	no obligation to reserve the lock for that particular client.		no obligation to reserve the lock for that particular client.
	</t>		</t>
	</section> <!-- title="Blocking Locks" -->		</section>
	<section anchor="share_reserve" title="Share Reservations" >		<section anchor="share_reserve" numbered="true" toc="default">
	<t>		<name>Share Reservations</name>
			<t>
	A share reservation is a mechanism to control access to a file. It is		A share reservation is a mechanism to control access to a file. It is
	a separate and independent mechanism from byte-range locking. When a		a separate and independent mechanism from byte-range locking. When a
	client opens a file, it sends an OPEN operation to the server		client opens a file, it sends an OPEN operation to the server
	specifying the type of access required (READ, WRITE, or BOTH) and the		specifying the type of access required (READ, WRITE, or BOTH) and the
	type of access to deny others (OPEN4_SHARE_DENY_NONE,		type of access to deny others (OPEN4_SHARE_DENY_NONE,
	OPEN4_SHARE_DENY_READ, OPEN4_SHARE_DENY_WRITE, or OPEN4_SHARE_DENY_BOTH). If		OPEN4_SHARE_DENY_READ, OPEN4_SHARE_DENY_WRITE, or OPEN4_SHARE_DENY_BOTH). If
	the OPEN fails, the client will fail the application's open request.		the OPEN fails, the client will fail the application's open request.
	</t>		</t>
	<t>		<t>
	Pseudo-code definition of the semantics:		Pseudo-code definition of the semantics:
	</t>		</t>
	<figure>		<sourcecode type="pseudocode"><![CDATA[
	<artwork>
	if (request.access == 0) {		if (request.access == 0) {
	return (NFS4ERR_INVAL)		return (NFS4ERR_INVAL)
	} else {		} else {
	if ((request.access &amp; file_state.deny)) ||		if ((request.access & file_state.deny)) ||
	(request.deny &amp; file_state.access)) {		(request.deny & file_state.access)) {
	return (NFS4ERR_SHARE_DENIED)		return (NFS4ERR_SHARE_DENIED)
	}		}
	return (NFS4ERR_OK);		return (NFS4ERR_OK);]]></sourcecode>
	</artwork>		<t>
	</figure>
	<t>
	When doing this checking of share reservations on OPEN, the current		When doing this checking of share reservations on OPEN, the current
	file_state used in the algorithm includes bits that reflect all		file_state used in the algorithm includes bits that reflect all
	current opens, including those for the open-owner making the		current opens, including those for the open-owner making the
	new OPEN request.		new OPEN request.
	</t>		</t>
	<t>		<t>
	The constants used for the OPEN and OPEN_DOWNGRADE operations for the		The constants used for the OPEN and OPEN_DOWNGRADE operations for the
	access and deny fields are as follows:		access and deny fields are as follows:
	</t>		</t>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	const OPEN4_SHARE_ACCESS_READ = 0x00000001;		const OPEN4_SHARE_ACCESS_READ = 0x00000001;
	const OPEN4_SHARE_ACCESS_WRITE = 0x00000002;		const OPEN4_SHARE_ACCESS_WRITE = 0x00000002;
	const OPEN4_SHARE_ACCESS_BOTH = 0x00000003;		const OPEN4_SHARE_ACCESS_BOTH = 0x00000003;
	const OPEN4_SHARE_DENY_NONE = 0x00000000;		const OPEN4_SHARE_DENY_NONE = 0x00000000;
	const OPEN4_SHARE_DENY_READ = 0x00000001;		const OPEN4_SHARE_DENY_READ = 0x00000001;
	const OPEN4_SHARE_DENY_WRITE = 0x00000002;		const OPEN4_SHARE_DENY_WRITE = 0x00000002;
	const OPEN4_SHARE_DENY_BOTH = 0x00000003;		const OPEN4_SHARE_DENY_BOTH = 0x00000003;]]></sourcecode>
	</artwork>		</section>
	</figure>		<section numbered="true" toc="default">
	</section> <!-- "Share Reservations" -->		<name>OPEN/CLOSE Operations</name>
	<section title="OPEN/CLOSE Operations" >		<t>
	<t>		To provide correct share semantics, a client <bcp14>MUST</bcp14> use the O
	To provide correct share semantics, a client MUST use the OPEN		PEN
	operation to obtain the initial filehandle and indicate the desired		operation to obtain the initial filehandle and indicate the desired
	access and what access, if any, to deny. Even if the client intends to		access and what access, if any, to deny. Even if the client intends to
	use a special stateid for anonymous state or READ bypass,		use a special stateid for anonymous state or READ bypass,
	it must still obtain the		it must still obtain the
	filehandle for the regular file with the OPEN operation so the		filehandle for the regular file with the OPEN operation so the
	appropriate share semantics can be applied. Clients that do not		appropriate share semantics can be applied. Clients that do not
	have a deny mode built into their programming interfaces for opening		have a deny mode built into their programming interfaces for opening
	a file should request a deny mode of		a file should request a deny mode of
	OPEN4_SHARE_DENY_NONE.		OPEN4_SHARE_DENY_NONE.
	</t>		</t>
	<t>		<t>
	The OPEN operation with the CREATE flag also subsumes the CREATE		The OPEN operation with the CREATE flag also subsumes the CREATE
	operation for regular files as used in previous versions of the NFS		operation for regular files as used in previous versions of the NFS
	protocol. This allows a create with a share to be done atomically.		protocol. This allows a create with a share to be done atomically.
	</t>		</t>
	<t>		<t>
	The CLOSE operation removes all share reservations held by the		The CLOSE operation removes all share reservations held by the
	open-owner on that file. If byte-range locks are held, the client		open-owner on that file. If byte-range locks are held, the client
	SHOULD release all locks before sending a CLOSE operation. The server MAY free		<bcp14>SHOULD</bcp14> release all locks before sending a CLOSE operation. The server <bcp14>MAY</bcp14> free
	all outstanding locks on CLOSE, but some servers may not support the		all outstanding locks on CLOSE, but some servers may not support the
	CLOSE of a file that still has byte-range locks held. The server MUST		CLOSE of a file that still has byte-range locks held. The server <bcp14>M UST</bcp14>
	return failure, NFS4ERR_LOCKS_HELD, if any locks would exist after the		return failure, NFS4ERR_LOCKS_HELD, if any locks would exist after the
	CLOSE.		CLOSE.
	</t>		</t>
	<t>		<t>
	The LOOKUP operation will return a filehandle without establishing any		The LOOKUP operation will return a filehandle without establishing any
	lock state on the server. Without a valid stateid, the server will		lock state on the server. Without a valid stateid, the server will
	assume that the client has the least access. For example, if one		assume that the client has the least access. For example, if one
	client opened a file with OPEN4_SHARE_DENY_BOTH and another client		client opened a file with OPEN4_SHARE_DENY_BOTH and another client
	accesses the file via a filehandle obtained through LOOKUP, the		accesses the file via a filehandle obtained through LOOKUP, the
	second client could only read the file using the special read		second client could only read the file using the special read
	bypass stateid. The second client could not WRITE the file		bypass stateid. The second client could not WRITE the file
	at all because it would		at all because it would
	not have a valid stateid from OPEN and the special anonymous stateid would		not have a valid stateid from OPEN and the special anonymous stateid would
	not be allowed access.		not be allowed access.
	</t>		</t>
	</section> <!-- "OPEN/CLOSE Operations" -->		</section>
	<section title="Open Upgrade and Downgrade" anchor="open_upgrade" >		<section anchor="open_upgrade" numbered="true" toc="default">
	<t>		<name>Open Upgrade and Downgrade</name>
			<t>
	When an OPEN is done for a file and the open-owner for which the OPEN		When an OPEN is done for a file and the open-owner for which the OPEN
	is being done already has the file open, the result is to upgrade the		is being done already has the file open, the result is to upgrade the
	open file status maintained on the server to include the access and		open file status maintained on the server to include the access and
	deny bits specified by the new OPEN as well as those for the existing		deny bits specified by the new OPEN as well as those for the existing
	OPEN. The result is that there is one open file, as far as the		OPEN. The result is that there is one open file, as far as the
	protocol is concerned, and it includes the union of the access and		protocol is concerned, and it includes the union of the access and
	deny bits for all of the OPEN requests completed. The OPEN		deny bits for all of the OPEN requests completed. The OPEN
	is represented by a single stateid whose "other" value matches		is represented by a single stateid whose "other" value matches
	that of the original open, and whose "seqid" value is incremented		that of the original open, and whose "seqid" value is incremented
	to reflect the occurrence of the upgrade. The increment is required		to reflect the occurrence of the upgrade. The increment is required
	skipping to change at line 12486 ¶		skipping to change at line 12758 ¶
	is done for read when the existing open file is opened for		is done for read when the existing open file is opened for
	OPEN4_SHARE_ACCESS_BOTH). Only a single CLOSE will be done to reset the		OPEN4_SHARE_ACCESS_BOTH). Only a single CLOSE will be done to reset the
	effects of both OPENs. The client may use the stateid returned		effects of both OPENs. The client may use the stateid returned
	by the OPEN effecting the upgrade or with a stateid sharing the		by the OPEN effecting the upgrade or with a stateid sharing the
	same "other" field and a seqid of zero,		same "other" field and a seqid of zero,
	although care needs to be taken as far as upgrades that happen		although care needs to be taken as far as upgrades that happen
	while the CLOSE is pending. Note that the		while the CLOSE is pending. Note that the
	client, when sending the OPEN, may not know that the same file is in		client, when sending the OPEN, may not know that the same file is in
	fact being opened. The above only applies if both OPENs result in		fact being opened. The above only applies if both OPENs result in
	the OPENed object being designated by the same filehandle.		the OPENed object being designated by the same filehandle.
	</t>		</t>
	<t>		<t>
	When the server chooses to export multiple filehandles corresponding		When the server chooses to export multiple filehandles corresponding
	to the same file object and returns different filehandles on two		to the same file object and returns different filehandles on two
	different OPENs of the same file object, the server MUST NOT "OR"		different OPENs of the same file object, the server <bcp14>MUST NOT</bcp14 > "OR"
	together the access and deny bits and coalesce the two open files.		together the access and deny bits and coalesce the two open files.
	Instead, the server must maintain separate OPENs with separate		Instead, the server must maintain separate OPENs with separate
	stateids and will require separate CLOSEs to free them.		stateids and will require separate CLOSEs to free them.
	</t>		</t>
	<t>		<t>
	When multiple open files on the client are merged into a single OPEN		When multiple open files on the client are merged into a single OPEN
	file object on the server, the close of one of the open files (on the		file object on the server, the close of one of the open files (on the
	client) may necessitate change of the access and deny status of the		client) may necessitate change of the access and deny status of the
	open file on the server. This is because the union of the access and		open file on the server. This is because the union of the access and
	deny bits for the remaining opens may be smaller (i.e., a proper		deny bits for the remaining opens may be smaller (i.e., a proper
	subset) than previously. The OPEN_DOWNGRADE operation is used to make		subset) than previously. The OPEN_DOWNGRADE operation is used to make
	the necessary change and the client should use it to update the server		the necessary change and the client should use it to update the server
	so that share reservation requests by other clients are handled		so that share reservation requests by other clients are handled
	properly. The stateid returned has the same "other" field as		properly. The stateid returned has the same "other" field as
	that passed to the server. The "seqid" value in the returned		that passed to the server. The "seqid" value in the returned
	stateid MUST be incremented, even in situations in which there is		stateid <bcp14>MUST</bcp14> be incremented, even in situations in which th ere is
	no change to the access and deny bits for the file.		no change to the access and deny bits for the file.
	</t>		</t>
	</section> <!-- "Open Upgrade and Downgrade" -->		</section>
	<section title="Parallel OPENs" anchor="parallel_opens">		<section anchor="parallel_opens" numbered="true" toc="default">
	<t>		<name>Parallel OPENs</name>
			<t>
	Unlike the case of NFSv4.0, in which OPEN operations for the same		Unlike the case of NFSv4.0, in which OPEN operations for the same
	open-owner are inherently serialized because of the owner-based seqid,		open-owner are inherently serialized because of the owner-based seqid,
	multiple OPENs for the same open-owner may be done in parallel. When		multiple OPENs for the same open-owner may be done in parallel. When
	clients do this, they may encounter situations in which, because		clients do this, they may encounter situations in which, because
	of the existence of hard links, two OPEN operations may turn out		of the existence of hard links, two OPEN operations may turn out
	to open the same file, with a later OPEN performed being an upgrade of		to open the same file, with a later OPEN performed being an upgrade of
	the first, with this fact only visible to the		the first, with this fact only visible to the
	client once the operations complete.		client once the operations complete.
	</t>		</t>
	<t>		<t>
	In this situation, clients may determine the order in which the		In this situation, clients may determine the order in which the
	OPENs were performed by examining the stateids returned by the OPENs.		OPENs were performed by examining the stateids returned by the OPENs.
	Stateids that share a common value of the "other" field can be		Stateids that share a common value of the "other" field can be
	recognized as having opened the same file, with the order of the		recognized as having opened the same file, with the order of the
	operations determinable from the order of the "seqid" fields, mod		operations determinable from the order of the "seqid" fields, mod
	any possible wraparound of the 32-bit field.		any possible wraparound of the 32-bit field.
	</t>		</t>
	<t>		<t>
	When the possibility exists that the client will send multiple		When the possibility exists that the client will send multiple
	OPENs for the same open-owner in parallel, it may be the case that		OPENs for the same open-owner in parallel, it may be the case that
	an open upgrade may happen without the client knowing beforehand		an open upgrade may happen without the client knowing beforehand
	that this could happen. Because of this possibility, CLOSEs and		that this could happen. Because of this possibility, CLOSEs and
	OPEN_DOWNGRADEs should generally be sent with a non-zero seqid		OPEN_DOWNGRADEs should generally be sent with a non-zero seqid
	in the stateid, to avoid the possibility that the status change		in the stateid, to avoid the possibility that the status change
	associated with an open upgrade is not inadvertently lost.		associated with an open upgrade is not inadvertently lost.
	</t>		</t>
	</section> <!-- "Parallel OPENs" -->		</section>
	<section title="Reclaim of Open and Byte-Range Locks" anchor="open_br_reclaim"		<section anchor="open_br_reclaim" numbered="true" toc="default">
	>		<name>Reclaim of Open and Byte-Range Locks</name>
	<t>		<t>
	Special forms of the LOCK and OPEN operations are provided when it		Special forms of the LOCK and OPEN operations are provided when it
	is necessary to re-establish byte-range locks or opens after a		is necessary to re-establish byte-range locks or opens after a
	server failure.		server failure.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	To reclaim existing opens, an OPEN operation is performed		To reclaim existing opens, an OPEN operation is performed
	using a CLAIM_PREVIOUS. Because the client, in this type		using a CLAIM_PREVIOUS. Because the client, in this type
	of situation, will have already opened the file and have		of situation, will have already opened the file and have
	the filehandle of the target file, this operation requires		the filehandle of the target file, this operation requires
	that the current filehandle be the target file, rather than		that the current filehandle be the target file, rather than
	a directory, and no file name is specified.		a directory, and no file name is specified.
	</t>		</li>
	<t>		<li>
	To reclaim byte-range locks, a LOCK operation with the		To reclaim byte-range locks, a LOCK operation with the
	reclaim parameter set to true is used.		reclaim parameter set to true is used.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Reclaims of opens associated with delegations are discussed in		Reclaims of opens associated with delegations are discussed in
	<xref target="delegation_recovery" />.		<xref target="delegation_recovery" format="default"/>.
	</t>		</t>
	</section>		</section>
	</section> <!-- "File Locking and Share Reservations" -->		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section numbered="true" toc="default">
	$ -->		<name>Client-Side Caching</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<t>
	<!-- Copyright (C) The Internet Society (2006) -->
	<section title="Client-Side Caching" >
	<t>
	Client-side caching of data, of file attributes, and of file names is		Client-side caching of data, of file attributes, and of file names is
	essential to providing good performance with the NFS protocol.		essential to providing good performance with the NFS protocol.
	Providing distributed cache coherence is a difficult problem, and		Providing distributed cache coherence is a difficult problem, and
	previous versions of the NFS protocol have not attempted it. Instead,		previous versions of the NFS protocol have not attempted it. Instead,
	several NFS client implementation techniques have been used to reduce		several NFS client implementation techniques have been used to reduce
	the problems that a lack of coherence poses for users. These		the problems that a lack of coherence poses for users. These
	techniques have not been clearly defined by earlier protocol		techniques have not been clearly defined by earlier protocol
	specifications, and it is often unclear what is valid or invalid client		specifications, and it is often unclear what is valid or invalid client
	behavior.		behavior.
	</t>		</t>
	<t>		<t>
	The NFSv4.1 protocol uses many techniques similar to those that		The NFSv4.1 protocol uses many techniques similar to those that
	have been used in previous protocol versions. The NFSv4.1		have been used in previous protocol versions. The NFSv4.1
	protocol does not provide distributed cache coherence. However, it		protocol does not provide distributed cache coherence. However, it
	defines a more limited set of caching guarantees to allow locks and		defines a more limited set of caching guarantees to allow locks and
	share reservations to be used without destructive interference from		share reservations to be used without destructive interference from
	client-side caching.		client-side caching.
	</t>		</t>
	<t>		<t>
	In addition, the NFSv4.1 protocol introduces a delegation		In addition, the NFSv4.1 protocol introduces a delegation
	mechanism, which allows many decisions normally made by the server to		mechanism, which allows many decisions normally made by the server to
	be made locally by clients. This mechanism provides efficient support		be made locally by clients. This mechanism provides efficient support
	of the common cases where sharing is infrequent or where sharing is		of the common cases where sharing is infrequent or where sharing is
	read-only.		read-only.
	</t>		</t>
	<section title="Performance Challenges for Client-Side Caching" >		<section numbered="true" toc="default">
	<t>		<name>Performance Challenges for Client-Side Caching</name>
			<t>
	Caching techniques used in previous versions of the NFS protocol have		Caching techniques used in previous versions of the NFS protocol have
	been successful in providing good performance. However, several		been successful in providing good performance. However, several
	scalability challenges can arise when those techniques are used with		scalability challenges can arise when those techniques are used with
	very large numbers of clients. This is particularly true when clients		very large numbers of clients. This is particularly true when clients
	are geographically distributed, which classically increases the latency		are geographically distributed, which classically increases the latency
	for cache revalidation requests.		for cache revalidation requests.
	</t>		</t>
	<t>		<t>
	The previous versions of the NFS protocol repeat their file data cache		The previous versions of the NFS protocol repeat their file data cache
	validation requests at the time the file is opened. This behavior can		validation requests at the time the file is opened. This behavior can
	have serious performance drawbacks. A common case is one in which a		have serious performance drawbacks. A common case is one in which a
	file is only accessed by a single client. Therefore, sharing is		file is only accessed by a single client. Therefore, sharing is
	infrequent.		infrequent.
	</t>		</t>
	<t>		<t>
	In this case, repeated references to the server to find that no		In this case, repeated references to the server to find that no
	conflicts exist are expensive. A better option with regards to		conflicts exist are expensive. A better option with regards to
	performance is to allow a client that repeatedly opens a file to do so		performance is to allow a client that repeatedly opens a file to do so
	without reference to the server. This is done until potentially		without reference to the server. This is done until potentially
	conflicting operations from another client actually occur.		conflicting operations from another client actually occur.
	</t>		</t>
	<t>		<t>
	A similar situation arises in connection with byte-range locking. Sending		A similar situation arises in connection with byte-range locking. Sending
	LOCK and LOCKU operations as well as the READ and		LOCK and LOCKU operations as well as the READ and
	WRITE operations necessary to make data caching consistent with the		WRITE operations necessary to make data caching consistent with the
	locking semantics (see <xref target="dc_file_locking" />)		locking semantics (see <xref target="dc_file_locking" format="default"/>)
	can severely limit performance. When locking is used to provide		can severely limit performance. When locking is used to provide
	protection against infrequent conflicts, a large penalty is incurred.		protection against infrequent conflicts, a large penalty is incurred.
	This penalty may discourage the use of byte-range locking by applications.		This penalty may discourage the use of byte-range locking by applications.
	</t>		</t>
	<t>		<t>
	The NFSv4.1 protocol provides more aggressive caching strategies		The NFSv4.1 protocol provides more aggressive caching strategies
	with the following design goals:		with the following design goals:
	<list style='symbols'>
	<t>
	Compatibility with a large range of server semantics.
	</t>		</t>
	<t>		<ul spacing="normal">
			<li>
			Compatibility with a large range of server semantics.
			</li>
			<li>
	Providing the same caching benefits as previous versions of		Providing the same caching benefits as previous versions of
	the NFS protocol when unable to support the more aggressive model.		the NFS protocol when unable to support the more aggressive model.
	</t>		</li>
	<t>		<li>
	Requirements for aggressive caching are organized so that a		Requirements for aggressive caching are organized so that a
	large portion of the benefit can be obtained even when not		large portion of the benefit can be obtained even when not
	all of the requirements can be met.		all of the requirements can be met.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The appropriate requirements for the server are discussed in later		The appropriate requirements for the server are discussed in later
	sections in which specific forms of caching are covered (see		sections in which specific forms of caching are covered (see
	<xref target="open_delegation" />).		<xref target="open_delegation" format="default"/>).
	</t>		</t>
	</section>		</section>
	<section title="Delegation and Callbacks" anchor="deleg_and_cb" >		<section anchor="deleg_and_cb" numbered="true" toc="default">
	<t>		<name>Delegation and Callbacks</name>
			<t>
	Recallable delegation of server responsibilities for a file to a		Recallable delegation of server responsibilities for a file to a
	client improves performance by avoiding repeated requests to the		client improves performance by avoiding repeated requests to the
	server in the absence of inter-client conflict. With the use of a		server in the absence of inter-client conflict. With the use of a
	"callback" RPC from server to client, a server recalls delegated		"callback" RPC from server to client, a server recalls delegated
	responsibilities when another client engages in sharing of a delegated		responsibilities when another client engages in sharing of a delegated
	file.		file.
	</t>		</t>
	<t>		<t>
	A delegation is passed from the server to the client, specifying the		A delegation is passed from the server to the client, specifying the
	object of the delegation and the type of delegation. There are		object of the delegation and the type of delegation. There are
	different types of delegations, but each type contains a stateid to be		different types of delegations, but each type contains a stateid to be
	used to represent the delegation when performing operations that		used to represent the delegation when performing operations that
	depend on the delegation. This stateid is similar to those associated		depend on the delegation. This stateid is similar to those associated
	with locks and share reservations but differs in that the stateid for		with locks and share reservations but differs in that the stateid for
	a delegation is associated with a client ID and may be used on behalf		a delegation is associated with a client ID and may be used on behalf
	of all the open-owners for the given client. A delegation is made		of all the open-owners for the given client. A delegation is made
	to the client as a whole and not to any specific process or thread of		to the client as a whole and not to any specific process or thread of
	control within it.		control within it.
	</t>		</t>
	<t>		<t>
	The backchannel is established by CREATE_SESSION and		The backchannel is established by CREATE_SESSION and
	BIND_CONN_TO_SESSION, and the client is required		BIND_CONN_TO_SESSION, and the client is required
	to maintain it. Because the backchannel may be down, even		to maintain it. Because the backchannel may be down, even
	temporarily,		temporarily,
	correct protocol operation does not depend on		correct protocol operation does not depend on
	them. Preliminary testing of backchannel functionality by means of a		them. Preliminary testing of backchannel functionality by means of a
	CB_COMPOUND procedure with a single operation, CB_SEQUENCE,		CB_COMPOUND procedure with a single operation, CB_SEQUENCE,
	can be used to check the continuity of the backchannel. A		can be used to check the continuity of the backchannel. A
	server avoids delegating responsibilities until it has		server avoids delegating responsibilities until it has
	determined that the backchannel exists. Because the granting of a		determined that the backchannel exists. Because the granting of a
	delegation is always conditional upon the absence of conflicting		delegation is always conditional upon the absence of conflicting
	access, clients MUST NOT assume that a delegation will be granted and		access, clients <bcp14>MUST NOT</bcp14> assume that a delegation will be g
	they MUST always be prepared for OPENs, WANT_DELEGATIONs, and		ranted and
			they <bcp14>MUST</bcp14> always be prepared for OPENs, WANT_DELEGATIONs, a
			nd
	GET_DIR_DELEGATIONs to be processed without any		GET_DIR_DELEGATIONs to be processed without any
	delegations being granted.		delegations being granted.
	</t>		</t>
	<t>		<t>
	Unlike locks, an operation by a second client to a delegated file will		Unlike locks, an operation by a second client to a delegated file will
	cause the server to recall a delegation through a callback. For		cause the server to recall a delegation through a callback. For
	individual operations, we will describe, under IMPLEMENTATION, when		individual operations, we will describe, under IMPLEMENTATION, when
	such operations are required to effect a recall. A number of		such operations are required to effect a recall. A number of
	points should be noted, however.		points should be noted, however.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The server is free to recall a delegation		The server is free to recall a delegation
	whenever it feels it is desirable and may do so even if no		whenever it feels it is desirable and may do so even if no
	operations requiring recall are being done.		operations requiring recall are being done.
	</t>		</li>
	<t>		<li>
	Operations done outside the NFSv4.1 protocol, due to, for		Operations done outside the NFSv4.1 protocol, due to, for
	example, access by other protocols, or by local access,		example, access by other protocols, or by local access,
	also need to result in delegation recall when they make		also need to result in delegation recall when they make
	analogous changes to file system data. What is crucial		analogous changes to file system data. What is crucial
	is if the change would invalidate the guarantees provided		is if the change would invalidate the guarantees provided
	by the delegation. When this is possible, the		by the delegation. When this is possible, the
	delegation needs to be recalled and MUST be returned or		delegation needs to be recalled and <bcp14>MUST</bcp14> be returned or
	revoked before allowing the operation to proceed.		revoked before allowing the operation to proceed.
	</t>		</li>
	<t>		<li>
	The semantics of the file system are crucial in defining		The semantics of the file system are crucial in defining
	when delegation recall is required. If a particular change		when delegation recall is required. If a particular change
	within a specific implementation causes change to a		within a specific implementation causes change to a
	file attribute, then delegation recall is required, whether		file attribute, then delegation recall is required, whether
	that operation has been specifically listed as requiring		that operation has been specifically listed as requiring
	delegation recall. Again, what is critical is whether the		delegation recall. Again, what is critical is whether the
	guarantees provided by the delegation are being invalidated.		guarantees provided by the delegation are being invalidated.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Despite those caveats, the implementation sections for a number		Despite those caveats, the implementation sections for a number
	of operations describe situations in which delegation recall		of operations describe situations in which delegation recall
	would be required under some common circumstances:		would be required under some common circumstances:
	<list style="symbols">
	<t>
	For GETATTR, see <xref target="OP_GETATTR_IMPLEMENTATION" />.
	</t>
	<t>
	For OPEN, see <xref target="OP_OPEN_IMPLEMENTATION" />.
	</t>
	<t>
	For READ, see <xref target="OP_READ_IMPLEMENTATION" />.
	</t>
	<t>
	For REMOVE, see <xref target="OP_REMOVE_IMPLEMENTATION" />.
	</t>
	<t>
	For RENAME, see <xref target="OP_RENAME_IMPLEMENTATION" />.
	</t>
	<t>
	For SETATTR, see <xref target="OP_SETATTR_IMPLEMENTATION" />.
	</t>		</t>
			<ul spacing="normal">
			<li>
			For GETATTR, see <xref target="OP_GETATTR_IMPLEMENTATION" format="defa
			ult"/>.
			</li>
			<li>
			For OPEN, see <xref target="OP_OPEN_IMPLEMENTATION" format="default"/>
			.
			</li>
			<li>
			For READ, see <xref target="OP_READ_IMPLEMENTATION" format="default"/>
			.
			</li>
			<li>
			For REMOVE, see <xref target="OP_REMOVE_IMPLEMENTATION" format="defaul
			t"/>.
			</li>
			<li>
			For RENAME, see <xref target="OP_RENAME_IMPLEMENTATION" format="defaul
			t"/>.
			</li>
			<li>
			For SETATTR, see <xref target="OP_SETATTR_IMPLEMENTATION" format="defa
			ult"/>.
			</li>
			<li>
			For WRITE, see <xref target="OP_WRITE_IMPLEMENTATION" format="default"
			/>.
			</li>
			</ul>
	<t>		<t>
	For WRITE, see <xref target="OP_WRITE_IMPLEMENTATION" />.
	</t>
	</list>
	</t>
	<t>
	On recall, the client holding the delegation needs to flush modified		On recall, the client holding the delegation needs to flush modified
	state (such as modified data) to the server and return the		state (such as modified data) to the server and return the
	delegation. The conflicting request will not be acted on until		delegation. The conflicting request will not be acted on until
	the recall is complete. The recall is considered complete when		the recall is complete. The recall is considered complete when
	the client returns the delegation or the server times its wait		the client returns the delegation or the server times its wait
	for the delegation to be returned and revokes the delegation as		for the delegation to be returned and revokes the delegation as
	a result of the timeout. In the interim, the server will either		a result of the timeout. In the interim, the server will either
	delay responding to conflicting requests or respond to them with		delay responding to conflicting requests or respond to them with
	NFS4ERR_DELAY. Following the resolution of the recall, the		NFS4ERR_DELAY. Following the resolution of the recall, the
	server has the information necessary to grant or deny the second		server has the information necessary to grant or deny the second
	client's request.		client's request.
	</t>		</t>
	<t>		<t>
	At the time the client receives a delegation recall, it may have		At the time the client receives a delegation recall, it may have
	substantial state that needs to be flushed to the server. Therefore,		substantial state that needs to be flushed to the server. Therefore,
	the server should allow sufficient time for the delegation to be		the server should allow sufficient time for the delegation to be
	returned since it may involve numerous RPCs to the server. If the		returned since it may involve numerous RPCs to the server. If the
	server is able to determine that the client is diligently flushing		server is able to determine that the client is diligently flushing
	state to the server as a result of the recall, the server may extend		state to the server as a result of the recall, the server may extend
	the usual time allowed for a recall. However, the time allowed for		the usual time allowed for a recall. However, the time allowed for
	recall completion should not be unbounded.		recall completion should not be unbounded.
	</t>		</t>
	<t>		<t>
	An example of this is when responsibility to mediate opens on a given		An example of this is when responsibility to mediate opens on a given
	file is delegated to a client (see <xref target="open_delegation" />).		file is delegated to a client (see <xref target="open_delegation" format=" default"/>).
	The server will not know what opens are in effect on the client.		The server will not know what opens are in effect on the client.
	Without this knowledge, the server will be unable to determine if the		Without this knowledge, the server will be unable to determine if the
	access and deny states for the file allow any particular open until		access and deny states for the file allow any particular open until
	the delegation for the file has been returned.		the delegation for the file has been returned.
	</t>		</t>
	<t>		<t>
	A client failure or a network partition can result in failure to		A client failure or a network partition can result in failure to
	respond to a recall callback. In this case, the server will revoke the		respond to a recall callback. In this case, the server will revoke the
	delegation, which in turn will render useless any modified state still		delegation, which in turn will render useless any modified state still
	on the client.		on the client.
	</t>		</t>
	<section title="Delegation Recovery"		<section anchor="delegation_recovery" numbered="true" toc="default">
	anchor="delegation_recovery" >		<name>Delegation Recovery</name>
	<t>
	There are three situations that delegation recovery needs to deal with:
	<list style="symbols">
	<t>		<t>
	client restart		There are three situations that delegation recovery needs to deal with:
	</t>		</t>
	<t>		<ul spacing="normal">
			<li>
			client restart
			</li>
			<li>
	server restart		server restart
	</t>		</li>
	<t>		<li>
	network partition (full or backchannel-only)		network partition (full or backchannel-only)
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	In the event the client restarts, the failure to renew		In the event the client restarts, the failure to renew
	the lease will result in the revocation of byte-range locks and share		the lease will result in the revocation of byte-range locks and share
	reservations. Delegations, however, may be treated a bit differently.		reservations. Delegations, however, may be treated a bit differently.
	</t>		</t>
	<t>		<t>
	There will be situations in which delegations will need to be		There will be situations in which delegations will need to be
	re-established after a client restarts. The reason for this		re-established after a client restarts. The reason for this
	is that the client may have file data stored locally and this data was		is that the client may have file data stored locally and this data was
	associated with the previously held delegations. The client will need		associated with the previously held delegations. The client will need
	to re-establish the appropriate file state on the server.		to re-establish the appropriate file state on the server.
	</t>		</t>
	<t>		<t>
	To allow for this type of client recovery, the server MAY extend the		To allow for this type of client recovery, the server <bcp14>MAY</bcp14>
			extend the
	period for delegation recovery beyond the typical lease expiration		period for delegation recovery beyond the typical lease expiration
	period. This implies that requests from other clients that conflict		period. This implies that requests from other clients that conflict
	with these delegations will need to wait. Because the normal recall		with these delegations will need to wait. Because the normal recall
	process may require significant time for the client to flush changed		process may require significant time for the client to flush changed
	state to the server, other clients need be prepared for delays that		state to the server, other clients need be prepared for delays that
	occur because of a conflicting delegation. This longer interval would		occur because of a conflicting delegation. This longer interval would
	increase the window for clients to restart and consult stable storage		increase the window for clients to restart and consult stable storage
	so that the delegations can be reclaimed. For OPEN delegations, such		so that the delegations can be reclaimed. For OPEN delegations, such
	delegations are reclaimed using OPEN with a claim type of		delegations are reclaimed using OPEN with a claim type of
	CLAIM_DELEGATE_PREV or CLAIM_DELEG_PREV_FH (see Sections		CLAIM_DELEGATE_PREV or CLAIM_DELEG_PREV_FH (see Sections
	<xref target="data_caching_revocation" format="counter" />		<xref target="data_caching_revocation" format="counter"/>
	and <xref target="OP_OPEN" format="counter" /> for discussion of OPEN de		and <xref target="OP_OPEN" format="counter"/> for discussion of OPEN del
	legation		egation
	and the details of OPEN, respectively).		and the details of OPEN, respectively).
	</t>		</t>
	<t>		<t>
	A server MAY support claim types of CLAIM_DELEGATE_PREV and		A server <bcp14>MAY</bcp14> support claim types of CLAIM_DELEGATE_PREV a
			nd
	CLAIM_DELEG_PREV_FH, and if it		CLAIM_DELEG_PREV_FH, and if it
	does, it MUST NOT remove delegations upon a CREATE_SESSION that		does, it <bcp14>MUST NOT</bcp14> remove delegations upon a CREATE_SESSIO N that
	confirm a client ID created by EXCHANGE_ID.		confirm a client ID created by EXCHANGE_ID.
	Instead, the server MUST, for a period of time no less than that of the value of		Instead, the server <bcp14>MUST</bcp14>, for a period of time no less th an that of the value of
	the lease_time attribute, maintain the client's delegations to allow		the lease_time attribute, maintain the client's delegations to allow
	time for the client to send CLAIM_DELEGATE_PREV and/or CLAIM_DELEG_PREV_ FH requests. The server		time for the client to send CLAIM_DELEGATE_PREV and/or CLAIM_DELEG_PREV_ FH requests. The server
	that supports CLAIM_DELEGATE_PREV and/or CLAIM_DELEG_PREV_FH MUST suppor t the DELEGPURGE		that supports CLAIM_DELEGATE_PREV and/or CLAIM_DELEG_PREV_FH <bcp14>MUST </bcp14> support the DELEGPURGE
	operation.		operation.
	</t>		</t>
	<t>		<t>
	When the server restarts, delegations are reclaimed (using		When the server restarts, delegations are reclaimed (using
	the OPEN operation with CLAIM_PREVIOUS) in a similar fashion to byte-ran ge		the OPEN operation with CLAIM_PREVIOUS) in a similar fashion to byte-ran ge
	locks and share reservations. However, there is a slight semantic		locks and share reservations. However, there is a slight semantic
	difference. In the normal case, if the server decides that a		difference. In the normal case, if the server decides that a
	delegation should not be granted, it performs the requested action		delegation should not be granted, it performs the requested action
	(e.g., OPEN) without granting any delegation. For reclaim, the server		(e.g., OPEN) without granting any delegation. For reclaim, the server
	grants the delegation but a special designation is applied so that the		grants the delegation but a special designation is applied so that the
	client treats the delegation as having been granted but recalled by		client treats the delegation as having been granted but recalled by
	the server. Because of this, the client has the duty to write all		the server. Because of this, the client has the duty to write all
	modified state to the server and then return the delegation. This		modified state to the server and then return the delegation. This
	process of handling delegation reclaim reconciles three principles of		process of handling delegation reclaim reconciles three principles of
	the NFSv4.1 protocol:		the NFSv4.1 protocol:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Upon reclaim, a client reporting resources assigned to it by an		Upon reclaim, a client reporting resources assigned to it by an
	earlier server instance must be granted those resources.		earlier server instance must be granted those resources.
	</t>		</li>
	<t>		<li>
	The server has unquestionable authority to determine whether		The server has unquestionable authority to determine whether
	delegations are to be granted and, once granted, whether they are to		delegations are to be granted and, once granted, whether they are to
	be continued.		be continued.
	</t>		</li>
	<t>		<li>
	The use of callbacks should not be depended upon until the client ha s		The use of callbacks should not be depended upon until the client ha s
	proven its ability to receive them.		proven its ability to receive them.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	When a client needs to reclaim a delegation and there is no associated		When a client needs to reclaim a delegation and there is no associated
	open, the client may use the CLAIM_PREVIOUS variant of the		open, the client may use the CLAIM_PREVIOUS variant of the
	WANT_DELEGATION operation. However, since the server is not required		WANT_DELEGATION operation. However, since the server is not required
	to support this operation, an alternative is to reclaim via a dummy OPEN		to support this operation, an alternative is to reclaim via a dummy OPEN
	together with the delegation		together with the delegation
	using an OPEN of type CLAIM_PREVIOUS. The dummy open file can		using an OPEN of type CLAIM_PREVIOUS. The dummy open file can
	be released using a CLOSE to re-establish the original state to be		be released using a CLOSE to re-establish the original state to be
	reclaimed, a delegation without an associated open.		reclaimed, a delegation without an associated open.
	</t>		</t>
	<t>		<t>
	When a client has more than a single open associated with a delegation,		When a client has more than a single open associated with a delegation,
	state for those additional opens can be established using OPEN		state for those additional opens can be established using OPEN
	operations of type CLAIM_DELEGATE_CUR. When these are used to		operations of type CLAIM_DELEGATE_CUR. When these are used to
	establish opens associated with reclaimed delegations, the		establish opens associated with reclaimed delegations, the
	server MUST allow them when made within the grace period.		server <bcp14>MUST</bcp14> allow them when made within the grace period.
	</t>		</t>
	<t>		<t>
	When a network partition occurs, delegations are subject to freeing by		When a network partition occurs, delegations are subject to freeing by
	the server when the lease renewal period expires. This is similar to		the server when the lease renewal period expires. This is similar to
	the behavior for locks and share reservations. For delegations,		the behavior for locks and share reservations. For delegations,
	however, the server may extend the period in which conflicting		however, the server may extend the period in which conflicting
	requests are held off. Eventually, the occurrence of a conflicting		requests are held off. Eventually, the occurrence of a conflicting
	request from another client will cause revocation of the delegation.		request from another client will cause revocation of the delegation.
	A loss of the backchannel (e.g., by later network configuration		A loss of the backchannel (e.g., by later network configuration
	change) will have the same effect. A recall request will fail and		change) will have the same effect. A recall request will fail and
	revocation of the delegation will result.		revocation of the delegation will result.
	</t>		</t>
	<t>		<t>
	A client normally finds out about revocation of a delegation when it		A client normally finds out about revocation of a delegation when it
	uses a stateid associated with a delegation and receives one of the		uses a stateid associated with a delegation and receives one of the
	errors NFS4ERR_EXPIRED, NFS4ERR_ADMIN_REVOKED, or NFS4ERR_DELEG_REVOKED.		errors NFS4ERR_EXPIRED, NFS4ERR_ADMIN_REVOKED, or NFS4ERR_DELEG_REVOKED.
	It also may find out about delegation revocation		It also may find out about delegation revocation
	after a client restart when it attempts to reclaim a delegation and		after a client restart when it attempts to reclaim a delegation and
	receives that same error. Note that in the case of a revoked OPEN_DELEG ATE_WRITE delegation, there are issues because data may have been modified		receives that same error. Note that in the case of a revoked OPEN_DELEG ATE_WRITE delegation, there are issues because data may have been modified
	by the client whose delegation is revoked and separately by other		by the client whose delegation is revoked and separately by other
	clients. See <xref target="revocation_recovery_write" />		clients. See <xref target="revocation_recovery_write" format="default"/ >
	for a discussion of such issues. Note also that when		for a discussion of such issues. Note also that when
	delegations are revoked, information about the revoked delegation will		delegations are revoked, information about the revoked delegation will
	be written by the server to stable storage (as described in		be written by the server to stable storage (as described in
	<xref target="network_partitions_and_recovery" />). This is done		<xref target="network_partitions_and_recovery" format="default"/>). Thi s is done
	to deal with the case in		to deal with the case in
	which a server restarts after revoking a delegation but before the		which a server restarts after revoking a delegation but before the
	client holding the revoked delegation is notified about the		client holding the revoked delegation is notified about the
	revocation.		revocation.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section title="Data Caching" >		<section numbered="true" toc="default">
	<t>		<name>Data Caching</name>
			<t>
	When applications share access to a set of files, they need to be		When applications share access to a set of files, they need to be
	implemented so as to take account of the possibility of conflicting		implemented so as to take account of the possibility of conflicting
	access by another application. This is true whether the applications		access by another application. This is true whether the applications
	in question execute on different clients or reside on the same client.		in question execute on different clients or reside on the same client.
	</t>		</t>
	<t>		<t>
	Share reservations and byte-range locks are the facilities the NFSv4.1 pro tocol		Share reservations and byte-range locks are the facilities the NFSv4.1 pro tocol
	provides to allow applications to coordinate access by		provides to allow applications to coordinate access by
	using mutual exclusion facilities. The NFSv4.1 protocol's		using mutual exclusion facilities. The NFSv4.1 protocol's
	data caching must be implemented such that it does not invalidate the		data caching must be implemented such that it does not invalidate the
	assumptions on which those using these facilities depend.		assumptions on which those using these facilities depend.
	</t>		</t>
	<section title="Data Caching and OPENs" >		<section numbered="true" toc="default">
	<t>		<name>Data Caching and OPENs</name>
			<t>
	In order to avoid invalidating the sharing assumptions on which		In order to avoid invalidating the sharing assumptions on which
	applications rely, NFSv4.1 clients should not provide cached		applications rely, NFSv4.1 clients should not provide cached
	data to applications or modify it on behalf of an application when it		data to applications or modify it on behalf of an application when it
	would not be valid to obtain or modify that same data via a READ or		would not be valid to obtain or modify that same data via a READ or
	WRITE operation.		WRITE operation.
	</t>		</t>
	<t>		<t>
	Furthermore, in the absence of an OPEN delegation		Furthermore, in the absence of an OPEN delegation
	(see <xref target="open_delegation" />),		(see <xref target="open_delegation" format="default"/>),
	two additional rules apply. Note that these rules are		two additional rules apply. Note that these rules are
	obeyed in practice by many NFSv3 clients.		obeyed in practice by many NFSv3 clients.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	First, cached data present on a client must be revalidated after doi ng		First, cached data present on a client must be revalidated after doi ng
	an OPEN. Revalidating means that the client fetches the change		an OPEN. Revalidating means that the client fetches the change
	attribute from the server, compares it with the cached change		attribute from the server, compares it with the cached change
	attribute, and if different, declares the cached data (as well as th e		attribute, and if different, declares the cached data (as well as th e
	cached attributes) as invalid. This is to ensure that the data for		cached attributes) as invalid. This is to ensure that the data for
	the OPENed file is still correctly reflected in the client's cache.		the OPENed file is still correctly reflected in the client's cache.
	This validation must be done at least when the client's OPEN operati on		This validation must be done at least when the client's OPEN operati on
	includes a deny of OPEN4_SHARE_DENY_WRITE or		includes a deny of OPEN4_SHARE_DENY_WRITE or
	OPEN4_SHARE_DENY_BOTH, thus terminating a period in which		OPEN4_SHARE_DENY_BOTH, thus terminating a period in which
	other		other
	clients may have had the opportunity to open the file with		clients may have had the opportunity to open the file with
	OPEN4_SHARE_ACCESS_WRITE/OPEN4_SHARE_ACCESS_BOTH		OPEN4_SHARE_ACCESS_WRITE/OPEN4_SHARE_ACCESS_BOTH
	access. Clients may choose to do the revalidation more often (i.e., at		access. Clients may choose to do the revalidation more often (i.e., at
	OPENs specifying a deny mode of OPEN4_SHARE_DENY_NONE) to parallel t he NFSv3 protocol's		OPENs specifying a deny mode of OPEN4_SHARE_DENY_NONE) to parallel t he NFSv3 protocol's
	practice for the benefit of users assuming this degree of cache		practice for the benefit of users assuming this degree of cache
	revalidation.		revalidation.
	<vspace blankLines='1' />		</t>
			<t>
	Since the change attribute is updated for data and metadata		Since the change attribute is updated for data and metadata
	modifications, some client implementors may be tempted to use the		modifications, some client implementors may be tempted to use the
	time_modify attribute and not the change attribute to validate cache d data, so that		time_modify attribute and not the change attribute to validate cache d data, so that
	metadata changes do not spuriously invalidate clean data. The		metadata changes do not spuriously invalidate clean data. The
	implementor is cautioned in this approach. The change attribute is		implementor is cautioned in this approach. The change attribute is
	guaranteed to change for each update to the file, whereas time_modif y		guaranteed to change for each update to the file, whereas time_modif y
	is guaranteed to change only at the granularity of the time_delta		is guaranteed to change only at the granularity of the time_delta
	attribute. Use by the client's data cache validation logic of		attribute. Use by the client's data cache validation logic of
	time_modify and not change runs the risk of the client incorrectly		time_modify and not change runs the risk of the client incorrectly
	marking stale data as valid. Thus, any cache validation approach		marking stale data as valid. Thus, any cache validation approach
	by the client MUST include the use of the change attribute.		by the client <bcp14>MUST</bcp14> include the use of the change attr
	</t>		ibute.
	<t>		</t>
			</li>
			<li>
	Second, modified data must be flushed to the server before closing a		Second, modified data must be flushed to the server before closing a
	file OPENed for OPEN4_SHARE_ACCESS_WRITE. This is complementary to the first rule. If		file OPENed for OPEN4_SHARE_ACCESS_WRITE. This is complementary to the first rule. If
	the data is not flushed at CLOSE, the revalidation done		the data is not flushed at CLOSE, the revalidation done
	after the client OPENs a file is unable to achieve its		after the client OPENs a file is unable to achieve its
	purpose. The other aspect to flushing the data before		purpose. The other aspect to flushing the data before
	close is that the data must be committed to stable		close is that the data must be committed to stable
	storage, at the server, before the CLOSE operation is		storage, at the server, before the CLOSE operation is
	requested by the client. In the case of a server restart and a CLOS Ed		requested by the client. In the case of a server restart and a CLOS Ed
	file, it may not be possible to retransmit the data to be written to		file, it may not be possible to retransmit the data to be written to
	the file, hence, this requirement.		the file, hence, this requirement.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section anchor="dc_file_locking" numbered="true" toc="default">
	<section title="Data Caching and File Locking" anchor="dc_file_locking">		<name>Data Caching and File Locking</name>
	<t>		<t>
	For those applications that choose to use byte-range locking instead of		For those applications that choose to use byte-range locking instead of
	share reservations to exclude inconsistent file access, there is an		share reservations to exclude inconsistent file access, there is an
	analogous set of constraints that apply to client-side data caching.		analogous set of constraints that apply to client-side data caching.
	These rules are effective only if the byte-range locking is used in a wa y		These rules are effective only if the byte-range locking is used in a wa y
	that matches in an equivalent way the actual READ and WRITE operations		that matches in an equivalent way the actual READ and WRITE operations
	executed. This is as opposed to byte-range locking that is based on pur e		executed. This is as opposed to byte-range locking that is based on pur e
	convention. For example, it is possible to manipulate a two-megabyte		convention. For example, it is possible to manipulate a two-megabyte
	file by dividing the file into two one-megabyte ranges and protecting		file by dividing the file into two one-megabyte ranges and protecting
	access to the two byte-ranges by byte-range locks on bytes zero and one. A WRITE_LT lock on		access to the two byte-ranges by byte-range locks on bytes zero and one. A WRITE_LT lock on
	byte zero of the file would represent the right to perform		byte zero of the file would represent the right to perform
	READ and WRITE operations on the first byte-range. A WRITE_LT lock on		READ and WRITE operations on the first byte-range. A WRITE_LT lock on
	byte one of the file would represent the right to perform READ and WRITE		byte one of the file would represent the right to perform READ and WRITE
	operations on the second byte-range. As long as all applications		operations on the second byte-range. As long as all applications
	manipulating the file obey this convention, they will work on a local		manipulating the file obey this convention, they will work on a local
	file system. However, they may not work with the NFSv4.1		file system. However, they may not work with the NFSv4.1
	protocol unless clients refrain from data caching.		protocol unless clients refrain from data caching.
	</t>		</t>
	<t>
	The rules for data caching in the byte-range locking environment are:
	<list style='symbols'>
	<t>		<t>
			The rules for data caching in the byte-range locking environment are:
			</t>
			<ul spacing="normal">
			<li>
	First, when a client obtains a byte-range lock for a particular byte -range, the		First, when a client obtains a byte-range lock for a particular byte -range, the
	data cache corresponding to that byte-range (if any cache data exist s)		data cache corresponding to that byte-range (if any cache data exist s)
	must be revalidated. If the change attribute indicates that the fil e		must be revalidated. If the change attribute indicates that the fil e
	may have been updated since the cached data was obtained, the client		may have been updated since the cached data was obtained, the client
	must flush or invalidate the cached data for the newly locked byte-r ange.		must flush or invalidate the cached data for the newly locked byte-r ange.
	A client might choose to invalidate all of the non-modified cached d ata		A client might choose to invalidate all of the non-modified cached d ata
	that it has for the file, but the only requirement for correct		that it has for the file, but the only requirement for correct
	operation is to invalidate all of the data in the newly locked byte- range.		operation is to invalidate all of the data in the newly locked byte- range.
	</t>		</li>
	<t>		<li>
	Second, before releasing a WRITE_LT lock for a byte-range, all modif ied data		Second, before releasing a WRITE_LT lock for a byte-range, all modif ied data
	for that byte-range must be flushed to the server. The modified dat a must		for that byte-range must be flushed to the server. The modified dat a must
	also be written to stable storage.		also be written to stable storage.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Note that flushing data to the server and the invalidation of cached		Note that flushing data to the server and the invalidation of cached
	data must reflect the actual byte-ranges locked or unlocked. Rounding		data must reflect the actual byte-ranges locked or unlocked. Rounding
	these up or down to reflect client cache block boundaries will cause		these up or down to reflect client cache block boundaries will cause
	problems if not carefully done. For example, writing a modified block		problems if not carefully done. For example, writing a modified block
	when only half of that block is within an area being unlocked may		when only half of that block is within an area being unlocked may
	cause invalid modification to the byte-range outside the unlocked area.		cause invalid modification to the byte-range outside the unlocked area.
	This, in turn, may be part of a byte-range locked by another client.		This, in turn, may be part of a byte-range locked by another client.
	Clients can avoid this situation by synchronously performing portions		Clients can avoid this situation by synchronously performing portions
	of WRITE operations that overlap that portion (initial or final) that		of WRITE operations that overlap that portion (initial or final) that
	is not a full block. Similarly, invalidating a locked area that is		is not a full block. Similarly, invalidating a locked area that is
	not an integral number of full buffer blocks would require the client		not an integral number of full buffer blocks would require the client
	to read one or two partial blocks from the server if the revalidation		to read one or two partial blocks from the server if the revalidation
	procedure shows that the data that the client possesses may not be		procedure shows that the data that the client possesses may not be
	valid.		valid.
	</t>		</t>
	<t>		<t>
	The data that is written to the server as a prerequisite to the		The data that is written to the server as a prerequisite to the
	unlocking of a byte-range must be written, at the server, to stable		unlocking of a byte-range must be written, at the server, to stable
	storage. The client may accomplish this either with synchronous		storage. The client may accomplish this either with synchronous
	writes or by following asynchronous writes with a COMMIT operation.		writes or by following asynchronous writes with a COMMIT operation.
	This is required because retransmission of the modified data after a		This is required because retransmission of the modified data after a
	server restart might conflict with a lock held by another client.		server restart might conflict with a lock held by another client.
	</t>		</t>
	<t>		<t>
	A client implementation may choose to accommodate applications that		A client implementation may choose to accommodate applications that
	use byte-range locking in non-standard ways (e.g., using a byte-range lo ck as a		use byte-range locking in non-standard ways (e.g., using a byte-range lo ck as a
	global semaphore) by flushing to the server more data upon a LOCKU		global semaphore) by flushing to the server more data upon a LOCKU
	than is covered by the locked range. This may include modified data		than is covered by the locked range. This may include modified data
	within files other than the one for which the unlocks are being done.		within files other than the one for which the unlocks are being done.
	In such cases, the client must not interfere with applications whose		In such cases, the client must not interfere with applications whose
	READs and WRITEs are being done only within the bounds of byte-range loc ks		READs and WRITEs are being done only within the bounds of byte-range loc ks
	that the application holds. For example, an application locks a		that the application holds. For example, an application locks a
	single byte of a file and proceeds to write that single byte. A		single byte of a file and proceeds to write that single byte. A
	client that chose to handle a LOCKU by flushing all modified data to		client that chose to handle a LOCKU by flushing all modified data to
	skipping to change at line 13080 ¶		skipping to change at line 13360 ¶
	unrelated LOCKU operation. However, it would not be valid to write the entire		unrelated LOCKU operation. However, it would not be valid to write the entire
	block in which that single written byte was located since it includes		block in which that single written byte was located since it includes
	an area that is not locked and might be locked by another client.		an area that is not locked and might be locked by another client.
	Client implementations can avoid this problem by dividing files with		Client implementations can avoid this problem by dividing files with
	modified data into those for which all modifications are done to areas		modified data into those for which all modifications are done to areas
	covered by an appropriate byte-range lock and those for which there are		covered by an appropriate byte-range lock and those for which there are
	modifications not covered by a byte-range lock. Any writes done for the		modifications not covered by a byte-range lock. Any writes done for the
	former class of files must not include areas not locked and thus not		former class of files must not include areas not locked and thus not
	modified on the client.		modified on the client.
	</t>		</t>
	</section>		</section>
	<section title="Data Caching and Mandatory File Locking" >		<section numbered="true" toc="default">
	<t>		<name>Data Caching and Mandatory File Locking</name>
			<t>
	Client-side data caching needs to respect mandatory byte-range locking w hen		Client-side data caching needs to respect mandatory byte-range locking w hen
	it is in effect. The presence of mandatory byte-range locking for a giv en		it is in effect. The presence of mandatory byte-range locking for a giv en
	file is indicated when the client gets back NFS4ERR_LOCKED from a READ		file is indicated when the client gets back NFS4ERR_LOCKED from a READ
	or WRITE operation on a file for which it has an appropriate share reser vation. When		or WRITE operation on a file for which it has an appropriate share reser vation. When
	mandatory locking is in effect for a file, the client must check for		mandatory locking is in effect for a file, the client must check for
	an appropriate byte-range lock for data being read or written. If a byt e-range lock		an appropriate byte-range lock for data being read or written. If a byt e-range lock
	exists for the range being read or written, the client may satisfy the		exists for the range being read or written, the client may satisfy the
	request using the client's validated cache. If an appropriate		request using the client's validated cache. If an appropriate
	byte-range lock is not held for the range of the read or write, the read or write		byte-range lock is not held for the range of the read or write, the read or write
	request must not be satisfied by the client's cache and the request		request must not be satisfied by the client's cache and the request
	must be sent to the server for processing. When a read or write		must be sent to the server for processing. When a read or write
	request partially overlaps a locked byte-range, the request should be		request partially overlaps a locked byte-range, the request should be
	subdivided into multiple pieces with each byte-range (locked or not)		subdivided into multiple pieces with each byte-range (locked or not)
	treated appropriately.		treated appropriately.
	</t>		</t>
	</section>		</section>
	<section anchor="data_caching_and_file_identity"		<section anchor="data_caching_and_file_identity" numbered="true" toc="de
	title="Data Caching and File Identity" >		fault">
			<name>Data Caching and File Identity</name>
	<t>		<t>
	When clients cache data, the file data needs to be organized according		When clients cache data, the file data needs to be organized according
	to the file system object to which the data belongs. For NFSv3		to the file system object to which the data belongs. For NFSv3
	clients, the typical practice has been to assume for the purpose of		clients, the typical practice has been to assume for the purpose of
	caching that distinct filehandles represent distinct file system		caching that distinct filehandles represent distinct file system
	objects. The client then has the choice to organize and maintain the		objects. The client then has the choice to organize and maintain the
	data cache on this basis.		data cache on this basis.
	</t>		</t>
	<t>		<t>
	In the NFSv4.1 protocol, there is now the possibility to have		In the NFSv4.1 protocol, there is now the possibility to have
	significant deviations from a "one filehandle per object" model		significant deviations from a "one filehandle per object" model
	because a filehandle may be constructed on the basis of the object's		because a filehandle may be constructed on the basis of the object's
	pathname. Therefore, clients need a reliable method to determine if		pathname. Therefore, clients need a reliable method to determine if
	two filehandles designate the same file system object. If clients		two filehandles designate the same file system object. If clients
	were simply to assume that all distinct filehandles denote distinct		were simply to assume that all distinct filehandles denote distinct
	objects and proceed to do data caching on this basis, caching		objects and proceed to do data caching on this basis, caching
	inconsistencies would arise between the distinct client-side objects		inconsistencies would arise between the distinct client-side objects
	that mapped to the same server-side object.		that mapped to the same server-side object.
	</t>		</t>
	<t>		<t>
	By providing a method to differentiate filehandles, the NFSv4.1		By providing a method to differentiate filehandles, the NFSv4.1
	protocol alleviates a potential functional regression in comparison		protocol alleviates a potential functional regression in comparison
	with the NFSv3 protocol. Without this method, caching		with the NFSv3 protocol. Without this method, caching
	inconsistencies within the same client could occur, and this has not		inconsistencies within the same client could occur, and this has not
	been present in previous versions of the NFS protocol. Note that it		been present in previous versions of the NFS protocol. Note that it
	is possible to have such inconsistencies with applications executing		is possible to have such inconsistencies with applications executing
	on multiple clients, but that is not the issue being addressed here.		on multiple clients, but that is not the issue being addressed here.
	</t>		</t>
	<t>		<t>
	For the purposes of data caching, the following steps allow an		For the purposes of data caching, the following steps allow an
	NFSv4.1 client to determine whether two distinct filehandles denote		NFSv4.1 client to determine whether two distinct filehandles denote
	the same server-side object:		the same server-side object:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	If GETATTR directed to two filehandles returns different values of t he		If GETATTR directed to two filehandles returns different values of t he
	fsid attribute, then the filehandles represent distinct objects.		fsid attribute, then the filehandles represent distinct objects.
	</t>		</li>
	<t>		<li>
	If GETATTR for any file with an fsid that matches the fsid of the tw o		If GETATTR for any file with an fsid that matches the fsid of the tw o
	filehandles in question returns a unique_handles attribute with a		filehandles in question returns a unique_handles attribute with a
	value of TRUE, then the two objects are distinct.		value of TRUE, then the two objects are distinct.
	</t>		</li>
	<t>		<li>
	If GETATTR directed to the two filehandles does not return the filei d		If GETATTR directed to the two filehandles does not return the filei d
	attribute for both of the handles, then it cannot be determined		attribute for both of the handles, then it cannot be determined
	whether the two objects are the same. Therefore,		whether the two objects are the same. Therefore,
	operations that depend on that knowledge (e.g.,		operations that depend on that knowledge (e.g.,
	client-side data caching) cannot be		client-side data caching) cannot be
	done reliably. Note that if GETATTR does not return the fileid		done reliably. Note that if GETATTR does not return the fileid
	attribute for both filehandles, it will return it for neither of		attribute for both filehandles, it will return it for neither of
	the filehandles, since the fsid for both filehandles is the same.		the filehandles, since the fsid for both filehandles is the same.
	</t>		</li>
	<t>		<li>
	If GETATTR directed to the two filehandles returns different values		If GETATTR directed to the two filehandles returns different values
	for the fileid attribute, then they are distinct objects.		for the fileid attribute, then they are distinct objects.
	</t>		</li>
	<t>		<li>
	Otherwise, they are the same object.		Otherwise, they are the same object.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="open_delegation" numbered="true" toc="default">
	<section title="Open Delegation" anchor="open_delegation" >		<name>Open Delegation</name>
	<t>		<t>
	When a file is being OPENed, the server may delegate further handling		When a file is being OPENed, the server may delegate further handling
	of opens and closes for that file to the opening client. Any such		of opens and closes for that file to the opening client. Any such
	delegation is recallable since the circumstances that allowed for the		delegation is recallable since the circumstances that allowed for the
	delegation are subject to change. In particular, if the server		delegation are subject to change. In particular, if the server
	receives a conflicting OPEN from another client, the server must recall		receives a conflicting OPEN from another client, the server must recall
	the delegation before deciding whether the OPEN from the other client		the delegation before deciding whether the OPEN from the other client
	may be granted. Making a delegation is up to the server, and clients		may be granted. Making a delegation is up to the server, and clients
	should not assume that any particular OPEN either will or will not		should not assume that any particular OPEN either will or will not
	result in an OPEN delegation. The following is a typical set of		result in an OPEN delegation. The following is a typical set of
	conditions that servers might use in deciding whether an OPEN should be		conditions that servers might use in deciding whether an OPEN should be
	delegated:		delegated:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The client must be able to respond to the		The client must be able to respond to the
	server's callback requests. If a backchannel		server's callback requests. If a backchannel
	has been established, the server will send		has been established, the server will send
	a CB_COMPOUND request, containing a single		a CB_COMPOUND request, containing a single
	operation, CB_SEQUENCE, for a test of backchannel		operation, CB_SEQUENCE, for a test of backchannel
	availability.		availability.
	</t>		</li>
	<t>		<li>
	The client must have responded properly to previous recalls.		The client must have responded properly to previous recalls.
	</t>		</li>
	<t>		<li>
	There must be no current OPEN conflicting with the requested		There must be no current OPEN conflicting with the requested
	delegation.		delegation.
	</t>		</li>
	<t>		<li>
	There should be no current delegation that conflicts with the		There should be no current delegation that conflicts with the
	delegation being requested.		delegation being requested.
	</t>		</li>
	<t>		<li>
	The probability of future conflicting open requests should be		The probability of future conflicting open requests should be
	low based on the recent history of the file.		low based on the recent history of the file.
	</t>		</li>
	<t>		<li>
	The existence of any server-specific semantics of OPEN/CLOSE		The existence of any server-specific semantics of OPEN/CLOSE
	that would make the required handling incompatible with the		that would make the required handling incompatible with the
	prescribed handling that the delegated client would apply		prescribed handling that the delegated client would apply
	(see below).		(see below).
	</t>		</li>
	</list>		</ul>
			<t>
	There are two types of OPEN delegations: OPEN_DELEGATE_READ and OPEN_DELEG ATE_WRITE. An OPEN_DELEGATE_READ		There are two types of OPEN delegations: OPEN_DELEGATE_READ and OPEN_DELEG ATE_WRITE. An OPEN_DELEGATE_READ
	delegation allows a client to handle, on its own, requests to open a		delegation allows a client to handle, on its own, requests to open a
	file for reading that do not deny OPEN4_SHARE_ACCESS_READ access to others . Multiple		file for reading that do not deny OPEN4_SHARE_ACCESS_READ access to others . Multiple
	OPEN_DELEGATE_READ delegations may be outstanding simultaneously and do no t		OPEN_DELEGATE_READ delegations may be outstanding simultaneously and do no t
	conflict. An OPEN_DELEGATE_WRITE delegation allows the client to handle, on its		conflict. An OPEN_DELEGATE_WRITE delegation allows the client to handle, on its
	own, all opens. Only OPEN_DELEGATE_WRITE delegation may exist for a given		own, all opens. Only one OPEN_DELEGATE_WRITE delegation may exist for a g iven
	file at a given time, and it is inconsistent with any OPEN_DELEGATE_READ d elegations.		file at a given time, and it is inconsistent with any OPEN_DELEGATE_READ d elegations.
	</t>		</t>
	<t>		<t>
	When a client has an OPEN_DELEGATE_READ delegation, it is assured that		When a client has an OPEN_DELEGATE_READ delegation, it is assured that
	neither the contents, the attributes (with the exception of		neither the contents, the attributes (with the exception of
	time_access), nor the names of any		time_access), nor the names of any
	links to the file will change without its knowledge, so long as the		links to the file will change without its knowledge, so long as the
	delegation is held. When a client has an OPEN_DELEGATE_WRITE delegation, it		delegation is held. When a client has an OPEN_DELEGATE_WRITE delegation, it
	may modify the file data locally since no other client will be		may modify the file data locally since no other client will be
	accessing the file's data. The client holding an OPEN_DELEGATE_WRITE dele gation		accessing the file's data. The client holding an OPEN_DELEGATE_WRITE dele gation
	may only locally affect file attributes that are intimately		may only locally affect file attributes that are intimately
	connected with the file data: size, change, time_access,		connected with the file data: size, change, time_access,
	time_metadata, and time_modify.		time_metadata, and time_modify.
	All other attributes must be reflected on the server.		All other attributes must be reflected on the server.
	</t>		</t>
	<t>		<t>
	When a client has an OPEN delegation, it does not need to send OPENs or		When a client has an OPEN delegation, it does not need to send OPENs or
	CLOSEs to the server. Instead, the client may update the		CLOSEs to the server. Instead, the client may update the
	appropriate status internally. For an OPEN_DELEGATE_READ delegation, opens		appropriate status internally. For an OPEN_DELEGATE_READ delegation, opens
	that cannot be handled locally (opens that are for OPEN4_SHARE_ACCESS_WRIT E/OPEN4_SHARE_ACCESS_BOTH or that		that cannot be handled locally (opens that are for OPEN4_SHARE_ACCESS_WRIT E/OPEN4_SHARE_ACCESS_BOTH or that
	deny OPEN4_SHARE_ACCESS_READ access) must be sent to the server.		deny OPEN4_SHARE_ACCESS_READ access) must be sent to the server.
	</t>		</t>
	<t>		<t>
	When an OPEN delegation is made, the reply to the OPEN contains an		When an OPEN delegation is made, the reply to the OPEN contains an
	OPEN delegation structure that specifies the following:		OPEN delegation structure that specifies the following:
	<list style="symbols">
	<t>
	the type of delegation (OPEN_DELEGATE_READ or OPEN_DELEGATE_WRITE).
	</t>		</t>
	<t>		<ul spacing="normal">
			<li>
			the type of delegation (OPEN_DELEGATE_READ or OPEN_DELEGATE_WRITE).
			</li>
			<li>
	space limitation information to control flushing of data on close		space limitation information to control flushing of data on close
	(OPEN_DELEGATE_WRITE delegation only;		(OPEN_DELEGATE_WRITE delegation only;
	see <xref target="open_delegation_caching" />)		see <xref target="open_delegation_caching" format="default"/>)
	</t>		</li>
	<t>		<li>
	an nfsace4 specifying read and write permissions		an nfsace4 specifying read and write permissions
	</t>		</li>
	<t>		<li>
	a stateid to represent the delegation		a stateid to represent the delegation
	</t>		</li>
	</list>		</ul>
			<t>
	The delegation stateid is separate and distinct from the stateid for		The delegation stateid is separate and distinct from the stateid for
	the OPEN proper. The standard stateid, unlike the delegation stateid,		the OPEN proper. The standard stateid, unlike the delegation stateid,
	is associated with a particular lock-owner and will continue to be		is associated with a particular lock-owner and will continue to be
	valid after the delegation is recalled and the file remains open.		valid after the delegation is recalled and the file remains open.
	</t>		</t>
	<t>		<t>
	When a request internal to the client is made to open a file and an OPEN		When a request internal to the client is made to open a file and an OPEN
	delegation is in effect, it will be accepted or rejected solely on the		delegation is in effect, it will be accepted or rejected solely on the
	basis of the following conditions. Any requirement for other checks		basis of the following conditions. Any requirement for other checks
	to be made by the delegate should result in the OPEN delegation being		to be made by the delegate should result in the OPEN delegation being
	denied so that the checks can be made by the server itself.		denied so that the checks can be made by the server itself.
	<list style="symbols">
	<t>
	The access and deny bits for the request and the file as
	described in <xref target="share_reserve" />.
	</t>		</t>
	<t>		<ul spacing="normal">
			<li>
			The access and deny bits for the request and the file as
			described in <xref target="share_reserve" format="default"/>.
			</li>
			<li>
	The read and write permissions as determined below.		The read and write permissions as determined below.
	</t>		</li>
	</list>		</ul>
			<t>
	The nfsace4 passed with delegation can be used to avoid frequent		The nfsace4 passed with delegation can be used to avoid frequent
	ACCESS calls. The permission check should be as follows:		ACCESS calls. The permission check should be as follows:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	If the nfsace4 indicates that the open may be done, then it should be		If the nfsace4 indicates that the open may be done, then it should be
	granted without reference to the server.		granted without reference to the server.
	</t>		</li>
	<t>		<li>
	If the nfsace4 indicates that the open may not be done, then an ACCESS		If the nfsace4 indicates that the open may not be done, then an ACCESS
	request must be sent to the server to obtain the definitive answer.		request must be sent to the server to obtain the definitive answer.
	</t>		</li>
	</list>		</ul>
			<t>
	The server may return an nfsace4 that is more restrictive than the		The server may return an nfsace4 that is more restrictive than the
	actual ACL of the file. This includes an nfsace4 that specifies		actual ACL of the file. This includes an nfsace4 that specifies
	denial of all access. Note that some common practices such as mapping		denial of all access. Note that some common practices such as mapping
	the traditional user "root" to the user "nobody" (see <xref target="owner_ owner_group"/>) may make it incorrect		the traditional user "root" to the user "nobody" (see <xref target="owner_ owner_group" format="default"/>) may make it incorrect
	to return the actual ACL of the file in the delegation response.		to return the actual ACL of the file in the delegation response.
	</t>		</t>
	<t>		<t>
	The use of a delegation together with various other forms of caching		The use of a delegation together with various other forms of caching
	creates the possibility that no server authentication and authorization		creates the possibility that no server authentication and authorization
	will ever be		will ever be
	performed for a given user since all of the user's requests might be		performed for a given user since all of the user's requests might be
	satisfied locally. Where the client is depending on the server for		satisfied locally. Where the client is depending on the server for
	authentication and authorization, the client should be sure authentication and authorization occurs for		authentication and authorization, the client should be sure authentication and authorization occurs for
	each user by use of the ACCESS operation. This should be the case		each user by use of the ACCESS operation. This should be the case
	even if an ACCESS operation would not be required otherwise. As		even if an ACCESS operation would not be required otherwise. As
	mentioned before, the server may enforce frequent authentication by		mentioned before, the server may enforce frequent authentication by
	returning an nfsace4 denying all access with every OPEN delegation.		returning an nfsace4 denying all access with every OPEN delegation.
	</t>		</t>
	<section title="Open Delegation and Data Caching"		<section anchor="open_delegation_caching" numbered="true" toc="default">
	anchor="open_delegation_caching" >		<name>Open Delegation and Data Caching</name>
	<t>		<t>
	An OPEN delegation allows much of the message overhead associated with		An OPEN delegation allows much of the message overhead associated with
	the opening and closing files to be eliminated. An open when an OPEN		the opening and closing files to be eliminated. An open when an OPEN
	delegation is in effect does not require that a validation		delegation is in effect does not require that a validation
	message be sent to the server. The continued endurance of the		message be sent to the server. The continued endurance of the
	"OPEN_DELEGATE_READ delegation" provides a guarantee that no OPEN		"OPEN_DELEGATE_READ delegation" provides a guarantee that no OPEN
	for OPEN4_SHARE_ACCESS_WRITE/OPEN4_SHARE_ACCESS_BOTH, and thus		for OPEN4_SHARE_ACCESS_WRITE/OPEN4_SHARE_ACCESS_BOTH, and thus
	no write, has occurred. Similarly, when closing a file opened		no write, has occurred. Similarly, when closing a file opened
	for OPEN4_SHARE_ACCESS_WRITE/OPEN4_SHARE_ACCESS_BOTH and if an OPEN_DELE GATE_WRITE delegation is in effect,		for OPEN4_SHARE_ACCESS_WRITE/OPEN4_SHARE_ACCESS_BOTH and if an OPEN_DELE GATE_WRITE delegation is in effect,
	the data written does not have to be written to the server until		the data written does not have to be written to the server until
	the OPEN delegation is recalled. The continued endurance of		the OPEN delegation is recalled. The continued endurance of
	the OPEN delegation provides a		the OPEN delegation provides a
	guarantee that no open, and thus no READ or WRITE, has been done by		guarantee that no open, and thus no READ or WRITE, has been done by
	another client.		another client.
	</t>		</t>
	<t>		<t>
	For the purposes of OPEN delegation, READs and WRITEs done without an		For the purposes of OPEN delegation, READs and WRITEs done without an
	OPEN are treated as the functional equivalents of a corresponding type		OPEN are treated as the functional equivalents of a corresponding type
	of OPEN. Although a client SHOULD NOT use special stateids when		of OPEN. Although a client <bcp14>SHOULD NOT</bcp14> use special statei ds when
	an open exists, delegation handling on the server can use the		an open exists, delegation handling on the server can use the
	client ID associated with the current session to determine if the		client ID associated with the current session to determine if the
	operation has been done by the holder of the delegation (in which		operation has been done by the holder of the delegation (in which
	case, no recall is necessary) or by another client (in which case,		case, no recall is necessary) or by another client (in which case,
	the delegation must be recalled and I/O not proceed until the		the delegation must be recalled and I/O not proceed until the
	delegation is returned or revoked).		delegation is returned or revoked).
	</t>		</t>
	<t>		<t>
	With delegations, a client is able to avoid writing data to the server		With delegations, a client is able to avoid writing data to the server
	when the CLOSE of a file is serviced. The file close system call is		when the CLOSE of a file is serviced. The file close system call is
	the usual point at which the client is notified of a lack of stable		the usual point at which the client is notified of a lack of stable
	storage for the modified file data generated by the application. At		storage for the modified file data generated by the application. At
	the close, file data is written to the server and, through normal		the close, file data is written to the server and, through normal
	accounting, the server is able to determine if the available file system		accounting, the server is able to determine if the available file system
	space for the data has been exceeded (i.e., the server returns		space for the data has been exceeded (i.e., the server returns
	NFS4ERR_NOSPC or NFS4ERR_DQUOT). This accounting includes quotas.		NFS4ERR_NOSPC or NFS4ERR_DQUOT). This accounting includes quotas.
	The introduction of delegations requires that an alternative method be		The introduction of delegations requires that an alternative method be
	in place for the same type of communication to occur between client		in place for the same type of communication to occur between client
	and server.		and server.
	</t>		</t>
	<t>		<t>
	In the delegation response, the server provides either the limit of		In the delegation response, the server provides either the limit of
	the size of the file or the number of modified blocks and associated		the size of the file or the number of modified blocks and associated
	block size. The server must ensure that the client will be able to		block size. The server must ensure that the client will be able to
	write modified data to the server of a size equal to that provided in th e		write modified data to the server of a size equal to that provided in th e
	original delegation. The server must make this assurance for all		original delegation. The server must make this assurance for all
	outstanding delegations. Therefore, the server must be careful in its		outstanding delegations. Therefore, the server must be careful in its
	management of available space for new or modified data, taking into		management of available space for new or modified data, taking into
	account available file system space and any applicable quotas. The		account available file system space and any applicable quotas. The
	server can recall delegations as a result of managing the available		server can recall delegations as a result of managing the available
	file system space. The client should abide by the server's state		file system space. The client should abide by the server's state
	space limits for delegations. If the client exceeds the stated limits		space limits for delegations. If the client exceeds the stated limits
	for the delegation, the server's behavior is undefined.		for the delegation, the server's behavior is undefined.
	</t>		</t>
	<t>		<t>
	Based on server conditions, quotas, or available file system space, the		Based on server conditions, quotas, or available file system space, the
	server may grant OPEN_DELEGATE_WRITE delegations with very restrictive s pace		server may grant OPEN_DELEGATE_WRITE delegations with very restrictive s pace
	limitations. The limitations may be defined in a way that will always		limitations. The limitations may be defined in a way that will always
	force modified data to be flushed to the server on close.		force modified data to be flushed to the server on close.
	</t>		</t>
	<t>		<t>
	With respect to authentication, flushing modified data to the server		With respect to authentication, flushing modified data to the server
	after a CLOSE has occurred may be problematic. For example, the user		after a CLOSE has occurred may be problematic. For example, the user
	of the application may have logged off the client, and unexpired		of the application may have logged off the client, and unexpired
	authentication credentials may not be present. In this case, the		authentication credentials may not be present. In this case, the
	client may need to take special care to ensure that local unexpired		client may need to take special care to ensure that local unexpired
	credentials will in fact be available. This may be accomplished by		credentials will in fact be available. This may be accomplished by
	tracking the expiration time of credentials and flushing data well in		tracking the expiration time of credentials and flushing data well in
	advance of their expiration or by making private copies of credentials		advance of their expiration or by making private copies of credentials
	to assure their availability when needed.		to assure their availability when needed.
	</t>		</t>
	</section>		</section>
	<section title="Open Delegation and File Locks" >		<section numbered="true" toc="default">
	<t>		<name>Open Delegation and File Locks</name>
			<t>
	When a client holds an OPEN_DELEGATE_WRITE delegation, lock operations a re		When a client holds an OPEN_DELEGATE_WRITE delegation, lock operations a re
	performed locally. This includes those required for mandatory byte-rang e		performed locally. This includes those required for mandatory byte-rang e
	locking. This can be done since the delegation implies that there can		locking. This can be done since the delegation implies that there can
	be no conflicting locks. Similarly, all of the revalidations that		be no conflicting locks. Similarly, all of the revalidations that
	would normally be associated with obtaining locks and the flushing of		would normally be associated with obtaining locks and the flushing of
	data associated with the releasing of locks need not be done.		data associated with the releasing of locks need not be done.
	</t>		</t>
	<t>		<t>
	When a client holds an OPEN_DELEGATE_READ delegation, lock operations ar e not		When a client holds an OPEN_DELEGATE_READ delegation, lock operations ar e not
	performed locally. All lock operations, including those requesting		performed locally. All lock operations, including those requesting
	non-exclusive locks, are sent to the server for resolution.		non-exclusive locks, are sent to the server for resolution.
	</t>		</t>
	</section>		</section>
	<section anchor="handling_cb_getattr" title="Handling of CB_GETATTR" >		<section anchor="handling_cb_getattr" numbered="true" toc="default">
	<t>		<name>Handling of CB_GETATTR</name>
			<t>
	The server needs to employ special handling for a GETATTR where the		The server needs to employ special handling for a GETATTR where the
	target is a file that has an OPEN_DELEGATE_WRITE delegation in effect. The		target is a file that has an OPEN_DELEGATE_WRITE delegation in effect. The
	reason for this is that the client holding the OPEN_DELEGATE_WRITE deleg ation may		reason for this is that the client holding the OPEN_DELEGATE_WRITE deleg ation may
	have modified the data, and the server needs to reflect this change to		have modified the data, and the server needs to reflect this change to
	the second client that submitted the GETATTR. Therefore, the client		the second client that submitted the GETATTR. Therefore, the client
	holding the OPEN_DELEGATE_WRITE delegation needs to be interrogated. Th e server		holding the OPEN_DELEGATE_WRITE delegation needs to be interrogated. Th e server
	will use the CB_GETATTR operation. The only attributes that the		will use the CB_GETATTR operation. The only attributes that the
	server can reliably query via CB_GETATTR are size and change.		server can reliably query via CB_GETATTR are size and change.
	</t>		</t>
	<t>		<t>
	Since CB_GETATTR is being used to satisfy another client's GETATTR		Since CB_GETATTR is being used to satisfy another client's GETATTR
	request, the server only needs to know if the client holding the		request, the server only needs to know if the client holding the
	delegation has a modified version of the file. If the client's copy		delegation has a modified version of the file. If the client's copy
	of the delegated file is not modified (data or size), the server can		of the delegated file is not modified (data or size), the server can
	satisfy the second client's GETATTR request from the attributes stored		satisfy the second client's GETATTR request from the attributes stored
	locally at the server. If the file is modified, the server only needs		locally at the server. If the file is modified, the server only needs
	to know about this modified state. If the server determines that the		to know about this modified state. If the server determines that the
	file is currently modified, it will respond to the second client's		file is currently modified, it will respond to the second client's
	GETATTR as if the file had been modified locally at the server.		GETATTR as if the file had been modified locally at the server.
	</t>		</t>
	<t>		<t>
	Since the form of the change attribute is determined by the server and		Since the form of the change attribute is determined by the server and
	is opaque to the client, the client and server need to agree on a		is opaque to the client, the client and server need to agree on a
	method of communicating the modified state of the file. For the size		method of communicating the modified state of the file. For the size
	attribute, the client will report its current view of the file size.		attribute, the client will report its current view of the file size.
	For the change attribute, the handling is more involved.		For the change attribute, the handling is more involved.
	</t>		</t>
	<t>		<t>
	For the client, the following steps will be taken when receiving an		For the client, the following steps will be taken when receiving an
	OPEN_DELEGATE_WRITE delegation:		OPEN_DELEGATE_WRITE delegation:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The value of the change attribute will be obtained from the server a nd		The value of the change attribute will be obtained from the server a nd
	cached. Let this value be represented by c.		cached. Let this value be represented by c.
	</t>		</li>
	<t>		<li>
	The client will create a value greater than c that will be used for		The client will create a value greater than c that will be used for
	communicating that modified data is held at the client. Let this va lue be		communicating that modified data is held at the client. Let this va lue be
	represented by d.		represented by d.
	</t>		</li>
	<t>		<li>
	When the client is queried via CB_GETATTR for the change attribute, it		When the client is queried via CB_GETATTR for the change attribute, it
	checks to see if it holds modified data. If the file is modified, t he		checks to see if it holds modified data. If the file is modified, t he
	value d is returned for the change attribute value. If this file is		value d is returned for the change attribute value. If this file is
	not currently modified, the client returns the value c for the chang e		not currently modified, the client returns the value c for the chang e
	attribute.		attribute.
	</t>		</li>
	</list>		</ul>
	For simplicity of implementation, the client MAY for each CB_GETATTR		<t>
			For simplicity of implementation, the client <bcp14>MAY</bcp14> for each
			CB_GETATTR
	return the same value d. This is true even if, between successive		return the same value d. This is true even if, between successive
	CB_GETATTR operations, the client again modifies the file's data or		CB_GETATTR operations, the client again modifies the file's data or
	metadata in its cache. The client can return the same value because		metadata in its cache. The client can return the same value because
	the only requirement is that the client be able to indicate to the		the only requirement is that the client be able to indicate to the
	server that the client holds modified data. Therefore, the value of d		server that the client holds modified data. Therefore, the value of d
	may always be c + 1.		may always be c + 1.
	</t>		</t>
	<t>		<t>
	While the change attribute is opaque to the client in the sense that		While the change attribute is opaque to the client in the sense that
	it has no idea what units of time, if any, the server is counting		it has no idea what units of time, if any, the server is counting
	change with, it is not opaque in that the client has to treat it as an		change with, it is not opaque in that the client has to treat it as an
	unsigned integer, and the server has to be able to see the results of		unsigned integer, and the server has to be able to see the results of
	the client's changes to that integer. Therefore, the server MUST		the client's changes to that integer. Therefore, the server <bcp14>MUST </bcp14>
	encode the change attribute in network order when sending it to the		encode the change attribute in network order when sending it to the
	client. The client MUST decode it from network order to its native		client. The client <bcp14>MUST</bcp14> decode it from network order to
	order when receiving it, and the client MUST encode it in network order		its native
			order when receiving it, and the client <bcp14>MUST</bcp14> encode it in
			network order
	when sending it to the server. For this reason, change is defined as		when sending it to the server. For this reason, change is defined as
	an unsigned integer rather than an opaque array of bytes.		an unsigned integer rather than an opaque array of bytes.
	</t>		</t>
	<t>		<t>
	For the server, the following steps will be taken when providing an		For the server, the following steps will be taken when providing an
	OPEN_DELEGATE_WRITE delegation:		OPEN_DELEGATE_WRITE delegation:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Upon providing an OPEN_DELEGATE_WRITE delegation, the server will ca che a copy of the		Upon providing an OPEN_DELEGATE_WRITE delegation, the server will ca che a copy of the
	change attribute in the data structure it uses to record the		change attribute in the data structure it uses to record the
	delegation. Let this value be represented by sc.		delegation. Let this value be represented by sc.
	</t>		</li>
	<t>		<li>
	When a second client sends a GETATTR operation on the same file to t he		When a second client sends a GETATTR operation on the same file to t he
	server, the server obtains the change attribute from the first clien t.		server, the server obtains the change attribute from the first clien t.
	Let this value be cc.		Let this value be cc.
	</t>		</li>
	<t>		<li>
	If the value cc is equal to sc, the file is not modified and the		If the value cc is equal to sc, the file is not modified and the
	server returns the current values for change, time_metadata, and		server returns the current values for change, time_metadata, and
	time_modify (for example) to the second client.		time_modify (for example) to the second client.
	</t>		</li>
	<t>		<li>
	If the value cc is NOT equal to sc, the file is currently modified a t		If the value cc is NOT equal to sc, the file is currently modified a t
	the first client and most likely will be modified at the server at a		the first client and most likely will be modified at the server at a
	future time. The server then uses its current time to construct		future time. The server then uses its current time to construct
	attribute values for time_metadata and time_modify. A new value of		attribute values for time_metadata and time_modify. A new value of
	sc, which we will call nsc, is computed by the server, such that nsc		sc, which we will call nsc, is computed by the server, such that nsc
	>= sc + 1. The server then returns the constructed time_metadata,		>= sc + 1. The server then returns the constructed time_metadata ,
	time_modify, and nsc values to the requester. The server replaces s c		time_modify, and nsc values to the requester. The server replaces s c
	in the delegation record with nsc. To prevent the possibility of		in the delegation record with nsc. To prevent the possibility of
	time_modify, time_metadata, and change from appearing to go backward		time_modify, time_metadata, and change from appearing to go backward
	(which would happen if the client holding the delegation fails to		(which would happen if the client holding the delegation fails to
	write its modified data to the server before the delegation is revok ed		write its modified data to the server before the delegation is revok ed
	or returned), the server SHOULD update the file's metadata record wi th		or returned), the server <bcp14>SHOULD</bcp14> update the file's met adata record with
	the constructed attribute values. For reasons of reasonable		the constructed attribute values. For reasons of reasonable
	performance, committing the constructed attribute values to stable		performance, committing the constructed attribute values to stable
	storage is OPTIONAL.		storage is <bcp14>OPTIONAL</bcp14>.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		As discussed earlier in this section, the client <bcp14>MAY</bcp14> retu
	As discussed earlier in this section, the client MAY return the same		rn the same
	cc value on subsequent CB_GETATTR calls, even if the file was modified		cc value on subsequent CB_GETATTR calls, even if the file was modified
	in the client's cache yet again between successive CB_GETATTR calls.		in the client's cache yet again between successive CB_GETATTR calls.
	Therefore, the server must assume that the file has been modified yet		Therefore, the server must assume that the file has been modified yet
	again, and MUST take care to ensure that the new nsc it constructs and		again, and <bcp14>MUST</bcp14> take care to ensure that the new nsc it c onstructs and
	returns is greater than the previous nsc it returned. An example		returns is greater than the previous nsc it returned. An example
	implementation's delegation record would satisfy this mandate by		implementation's delegation record would satisfy this mandate by
	including a boolean field (let us call it "modified") that is set to		including a boolean field (let us call it "modified") that is set to
	FALSE when the delegation is granted, and an sc value set at the time		FALSE when the delegation is granted, and an sc value set at the time
	of grant to the change attribute value. The modified field would be		of grant to the change attribute value. The modified field would be
	set to TRUE the first time cc != sc, and would stay TRUE until the		set to TRUE the first time cc != sc, and would stay TRUE until the
	delegation is returned or revoked. The processing for constructing		delegation is returned or revoked. The processing for constructing
	nsc, time_modify, and time_metadata would use this pseudo code:		nsc, time_modify, and time_metadata would use this pseudo code:
	<figure>		</t>
	<artwork>		<sourcecode type="pseudocode"><![CDATA[
	if (!modified) {		if (!modified) {
	do CB_GETATTR for change and size;		do CB_GETATTR for change and size;
	if (cc != sc)		if (cc != sc)
	modified = TRUE;		modified = TRUE;
	} else {		} else {
	do CB_GETATTR for size;		do CB_GETATTR for size;
	}		}
	if (modified) {		if (modified) {
	sc = sc + 1;		sc = sc + 1;
	time_modify = time_metadata = current_time;		time_modify = time_metadata = current_time;
	update sc, time_modify, time_metadata into file's metadata;		update sc, time_modify, time_metadata into file's metadata;
	}		}]]></sourcecode>
			<t>
	</artwork>
	</figure>
	This would return to the client (that sent GETATTR) the attributes		This would return to the client (that sent GETATTR) the attributes
	it requested, but make sure size comes from what		it requested, but make sure size comes from what
	CB_GETATTR returned. The server would not update the file's		CB_GETATTR returned. The server would not update the file's
	metadata with the client's modified size.		metadata with the client's modified size.
	</t>		</t>
	<t>		<t>
	In the case that the file attribute size is different than the		In the case that the file attribute size is different than the
	server's current value, the server treats this as a modification		server's current value, the server treats this as a modification
	regardless of the value of the change attribute retrieved via		regardless of the value of the change attribute retrieved via
	CB_GETATTR and responds to the second client as in the last step.		CB_GETATTR and responds to the second client as in the last step.
	</t>		</t>
	<t>		<t>
	This methodology resolves issues of clock differences between client		This methodology resolves issues of clock differences between client
	and server and other scenarios where the use of CB_GETATTR break down.		and server and other scenarios where the use of CB_GETATTR break down.
	</t>		</t>
	<t>		<t>
	It should be noted that the server is under no obligation to use		It should be noted that the server is under no obligation to use
	CB_GETATTR, and therefore the server MAY simply recall the delegation		CB_GETATTR, and therefore the server <bcp14>MAY</bcp14> simply recall th e delegation
	to avoid its use.		to avoid its use.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="Recall of Open Delegation" >		<name>Recall of Open Delegation</name>
	<t>
	The following events necessitate recall of an OPEN delegation:
	<list style="symbols">
	<t>		<t>
			The following events necessitate recall of an OPEN delegation:
			</t>
			<ul spacing="normal">
			<li>
	potentially conflicting OPEN request (or a READ or WRITE operation		potentially conflicting OPEN request (or a READ or WRITE operation
	done with a special stateid)		done with a special stateid)
	</t>		</li>
	<t>		<li>
	SETATTR sent by another client		SETATTR sent by another client
	</t>		</li>
	<t>		<li>
	REMOVE request for the file		REMOVE request for the file
	</t>		</li>
	<t>		<li>
	RENAME request for the file as either the source or target of the RE NAME		RENAME request for the file as either the source or target of the RE NAME
	</t>		</li>
	</list>		</ul>
			<t>
	Whether a RENAME of a directory in the path leading to the file		Whether a RENAME of a directory in the path leading to the file
	results in recall of an OPEN delegation depends on the semantics of		results in recall of an OPEN delegation depends on the semantics of
	the server's file system. If that file system denies such RENAMEs when		the server's file system. If that file system denies such RENAMEs when
	a file is open, the recall must be performed to determine whether the		a file is open, the recall must be performed to determine whether the
	file in question is, in fact, open.		file in question is, in fact, open.
	</t>		</t>
	<t>		<t>
	In addition to the situations above, the server may choose to recall		In addition to the situations above, the server may choose to recall
	OPEN delegations at any time if resource constraints make it advisable		OPEN delegations at any time if resource constraints make it advisable
	to do so. Clients should always be prepared for the possibility of		to do so. Clients should always be prepared for the possibility of
	recall.		recall.
	</t>		</t>
	<t>		<t>
	When a client receives a recall for an OPEN delegation, it needs		When a client receives a recall for an OPEN delegation, it needs
	to update state on the server before returning the delegation.		to update state on the server before returning the delegation.
	These same updates must be done whenever a client chooses to		These same updates must be done whenever a client chooses to
	return a delegation voluntarily. The following items of state		return a delegation voluntarily. The following items of state
	need to be dealt with:		need to be dealt with:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	If the file associated with the delegation is no longer open and no		If the file associated with the delegation is no longer open and no
	previous CLOSE operation has been sent to the server, a CLOSE		previous CLOSE operation has been sent to the server, a CLOSE
	operation must be sent to the server.		operation must be sent to the server.
	</t>		</li>
	<t>		<li>
	If a file has other open references at the client, then OPEN		If a file has other open references at the client, then OPEN
	operations must be sent to the server. The appropriate stateids wil l		operations must be sent to the server. The appropriate stateids wil l
	be provided by the server for subsequent use by the client since the		be provided by the server for subsequent use by the client since the
	delegation stateid will no longer be valid. These OPEN requests are		delegation stateid will no longer be valid. These OPEN requests are
	done with the claim type of CLAIM_DELEGATE_CUR. This will allow the		done with the claim type of CLAIM_DELEGATE_CUR. This will allow the
	presentation of the delegation stateid so that the client can		presentation of the delegation stateid so that the client can
	establish the appropriate rights to perform the OPEN. (see		establish the appropriate rights to perform the OPEN. (See
	<xref target="OP_OPEN" />, which describes the OPEN operation,		<xref target="OP_OPEN" format="default"/>, which describes the OPEN
			operation,
	for details.)		for details.)
	</t>		</li>
	<t>		<li>
	If there are granted byte-range locks, the corresponding LOCK operat ions		If there are granted byte-range locks, the corresponding LOCK operat ions
	need to be performed. This applies to the OPEN_DELEGATE_WRITE deleg ation case		need to be performed. This applies to the OPEN_DELEGATE_WRITE deleg ation case
	only.		only.
	</t>		</li>
	<t>		<li>
	For an OPEN_DELEGATE_WRITE delegation, if		For an OPEN_DELEGATE_WRITE delegation, if
	at the time of recall the file is not open for		at the time of recall the file is not open for
	OPEN4_SHARE_ACCESS_WRITE/OPEN4_SHARE_ACCESS_BOTH, all modified		OPEN4_SHARE_ACCESS_WRITE/OPEN4_SHARE_ACCESS_BOTH, all modified
	data for the file must be flushed to the		data for the file must be flushed to the
	server. If the delegation had not existed, the client would have do ne		server. If the delegation had not existed, the client would have do ne
	this data flush before the CLOSE operation.		this data flush before the CLOSE operation.
	</t>		</li>
	<t>		<li>
	For an OPEN_DELEGATE_WRITE delegation when a file is still open at t he time of		For an OPEN_DELEGATE_WRITE delegation when a file is still open at t he time of
	recall, any modified data for the file needs to be flushed to the		recall, any modified data for the file needs to be flushed to the
	server.		server.
	</t>		</li>
	<t>		<li>
	With the OPEN_DELEGATE_WRITE delegation in place, it is possible tha t the file		With the OPEN_DELEGATE_WRITE delegation in place, it is possible tha t the file
	was truncated during the duration of the delegation. For example, t he		was truncated during the duration of the delegation. For example, t he
	truncation could have occurred as a result of an OPEN UNCHECKED with a		truncation could have occurred as a result of an OPEN UNCHECKED with a
	size attribute value of zero. Therefore, if a truncation of		size attribute value of zero. Therefore, if a truncation of
	the file has occurred and this operation has not been propagated to		the file has occurred and this operation has not been propagated to
	the server, the truncation must occur before any modified data is		the server, the truncation must occur before any modified data is
	written to the server.		written to the server.
	</t>		</li>
	</list>		</ul>
			<t>
	In the case of OPEN_DELEGATE_WRITE delegation, byte-range locking impose s some		In the case of OPEN_DELEGATE_WRITE delegation, byte-range locking impose s some
	additional requirements. To precisely maintain the associated		additional requirements. To precisely maintain the associated
	invariant, it is required to flush any modified data in any byte-range f or		invariant, it is required to flush any modified data in any byte-range f or
	which a WRITE_LT lock was released while the OPEN_DELEGATE_WRITE delegat ion was in		which a WRITE_LT lock was released while the OPEN_DELEGATE_WRITE delegat ion was in
	effect. However, because the OPEN_DELEGATE_WRITE delegation implies no other		effect. However, because the OPEN_DELEGATE_WRITE delegation implies no other
	locking by other clients, a simpler implementation is to flush all		locking by other clients, a simpler implementation is to flush all
	modified data for the file (as described just above) if any WRITE_LT loc k		modified data for the file (as described just above) if any WRITE_LT loc k
	has been released while the OPEN_DELEGATE_WRITE delegation was in effect .		has been released while the OPEN_DELEGATE_WRITE delegation was in effect .
	</t>		</t>
	<t>		<t>
	An implementation need not wait until delegation recall (or		An implementation need not wait until delegation recall (or
	the decision to voluntarily return a delegation) to perform any of the a bove		the decision to voluntarily return a delegation) to perform any of the a bove
	actions, if implementation considerations (e.g., resource availability		actions, if implementation considerations (e.g., resource availability
	constraints) make that desirable. Generally, however, the fact that		constraints) make that desirable. Generally, however, the fact that
	the actual OPEN state of the file may continue to change makes it not		the actual OPEN state of the file may continue to change makes it not
	worthwhile to send information about opens and closes to the server,		worthwhile to send information about opens and closes to the server,
	except as part of delegation return. An exception is		except as part of delegation return. An exception is
	when the client has no more internal opens of the file. In this		when the client has no more internal opens of the file. In this
	case, sending a CLOSE is useful because it		case, sending a CLOSE is useful because it
	reduces resource utilization on the client		reduces resource utilization on the client
	and server.		and server.
	Regardless of the client's choices on scheduling these		Regardless of the client's choices on scheduling these
	actions, all must be performed before the delegation is returned,		actions, all must be performed before the delegation is returned,
	including (when applicable) the close that corresponds to the OPEN		including (when applicable) the close that corresponds to the OPEN
	that resulted in the delegation. These actions can be performed		that resulted in the delegation. These actions can be performed
	either in previous requests or in previous operations in the same		either in previous requests or in previous operations in the same
	COMPOUND request.		COMPOUND request.
	</t>		</t>
	</section>		</section>
	<section title="Clients That Fail to Honor Delegation Recalls" >		<section numbered="true" toc="default">
	<t>		<name>Clients That Fail to Honor Delegation Recalls</name>
			<t>
	A client may fail to respond to a recall for various reasons, such as		A client may fail to respond to a recall for various reasons, such as
	a failure of the backchannel from server to the client. The client		a failure of the backchannel from server to the client. The client
	may be unaware of a failure in the backchannel. This lack of		may be unaware of a failure in the backchannel. This lack of
	awareness could result in the client finding out long after the		awareness could result in the client finding out long after the
	failure that its delegation has been revoked, and another client has		failure that its delegation has been revoked, and another client has
	modified the data for which the client had a delegation. This is		modified the data for which the client had a delegation. This is
	especially a problem for the client that held an OPEN_DELEGATE_WRITE del egation.		especially a problem for the client that held an OPEN_DELEGATE_WRITE del egation.
	</t>		</t>
	<t>		<t>
	Status bits returned by SEQUENCE operations help to provide an		Status bits returned by SEQUENCE operations help to provide an
	alternate way of informing the client of issues regarding the		alternate way of informing the client of issues regarding the
	status of the backchannel and of recalled delegations. When the		status of the backchannel and of recalled delegations. When the
	backchannel is not available, the server returns the status bit		backchannel is not available, the server returns the status bit
	SEQ4_STATUS_CB_PATH_DOWN on SEQUENCE operations. The client can		SEQ4_STATUS_CB_PATH_DOWN on SEQUENCE operations. The client can
	react by attempting to re-establish the backchannel and by		react by attempting to re-establish the backchannel and by
	returning recallable objects if a backchannel cannot be successfully		returning recallable objects if a backchannel cannot be successfully
	re-established.		re-established.
	</t>		</t>
	<t>		<t>
	Whether the backchannel is functioning or not, it may be that the		Whether the backchannel is functioning or not, it may be that the
	recalled delegation is not returned. Note that the client's lease		recalled delegation is not returned. Note that the client's lease
	might still be renewed, even though the recalled delegation is not		might still be renewed, even though the recalled delegation is not
	returned. In this situation, servers SHOULD revoke delegations that		returned. In this situation, servers <bcp14>SHOULD</bcp14> revoke deleg ations that
	are not returned in a period of time equal to the lease period. This		are not returned in a period of time equal to the lease period. This
	period of time should allow the client time to note the		period of time should allow the client time to note the
	backchannel-down status and re-establish the backchannel.		backchannel-down status and re-establish the backchannel.
	</t>		</t>
	<t>		<t>
	When delegations are revoked, the server will return with the		When delegations are revoked, the server will return with the
	SEQ4_STATUS_RECALLABLE_STATE_REVOKED status bit set on subsequent		SEQ4_STATUS_RECALLABLE_STATE_REVOKED status bit set on subsequent
	SEQUENCE operations. The client should note this and then use		SEQUENCE operations. The client should note this and then use
	TEST_STATEID to find which delegations have been revoked.		TEST_STATEID to find which delegations have been revoked.
	</t>		</t>
	</section>		</section>
	<section title="Delegation Revocation" >		<section numbered="true" toc="default">
	<t>		<name>Delegation Revocation</name>
			<t>
	At the point a delegation is revoked, if there are associated opens		At the point a delegation is revoked, if there are associated opens
	on the client, these opens may or may not be revoked. If no		on the client, these opens may or may not be revoked. If no
	byte-range lock or open is granted that is inconsistent with the existin g open,		byte-range lock or open is granted that is inconsistent with the existin g open,
	the stateid for the open may remain valid and be disconnected		the stateid for the open may remain valid and be disconnected
	from the revoked delegation, just as would be the case if the		from the revoked delegation, just as would be the case if the
	delegation were returned.		delegation were returned.
	</t>		</t>
	<t>		<t>
	For example, if an OPEN for OPEN4_SHARE_ACCESS_BOTH with a deny of OPEN4 _SHARE_DENY_NONE is		For example, if an OPEN for OPEN4_SHARE_ACCESS_BOTH with a deny of OPEN4 _SHARE_DENY_NONE is
	associated with the delegation, granting of another such OPEN		associated with the delegation, granting of another such OPEN
	to a different client will revoke the delegation but need not		to a different client will revoke the delegation but need not
	revoke the OPEN, since the two OPENs are consistent with each other.		revoke the OPEN, since the two OPENs are consistent with each other.
	On the other hand, if an OPEN denying write access is		On the other hand, if an OPEN denying write access is
	granted, then the existing OPEN must be revoked.		granted, then the existing OPEN must be revoked.
	</t>		</t>
	<t>		<t>
	When opens and/or locks are revoked,		When opens and/or locks are revoked,
	the applications holding these opens or locks need to be notified.		the applications holding these opens or locks need to be notified.
	This notification usually occurs by returning errors for READ/WRITE		This notification usually occurs by returning errors for READ/WRITE
	operations or when a close is attempted for the open file.		operations or when a close is attempted for the open file.
	</t>		</t>
	<t>		<t>
	If no opens exist for the file at the point the delegation is revoked,		If no opens exist for the file at the point the delegation is revoked,
	then notification of the revocation is unnecessary. However, if there		then notification of the revocation is unnecessary. However, if there
	is modified data present at the client for the file, the user of the		is modified data present at the client for the file, the user of the
	application should be notified. Unfortunately, it may not be possible		application should be notified. Unfortunately, it may not be possible
	to notify the user since active applications may not be present at the		to notify the user since active applications may not be present at the
	client. See <xref target="revocation_recovery_write" />		client. See <xref target="revocation_recovery_write" format="default"/>
	for additional details.		for additional details.
	</t>		</t>
	</section>		</section>
	<section title="Delegations via WANT_DELEGATION"		<section anchor="via_want_delegation" numbered="true" toc="default">
	anchor="via_want_delegation" >		<name>Delegations via WANT_DELEGATION</name>
	<t>		<t>
	In addition to providing delegations as part of the reply		In addition to providing delegations as part of the reply
	to OPEN operations, servers MAY provide delegations		to OPEN operations, servers <bcp14>MAY</bcp14> provide delegations
	separate from open, via the OPTIONAL WANT_DELEGATION operation. This		separate from open, via the <bcp14>OPTIONAL</bcp14> WANT_DELEGATION oper
			ation. This
	allows delegations to be obtained in advance of an OPEN that		allows delegations to be obtained in advance of an OPEN that
	might benefit from them, for objects that are not a valid target		might benefit from them, for objects that are not a valid target
	of OPEN, or to deal with cases in which a		of OPEN, or to deal with cases in which a
	delegation has been recalled and the client wants to make		delegation has been recalled and the client wants to make
	an attempt to re-establish it if the absence of use by other		an attempt to re-establish it if the absence of use by other
	clients allows that.		clients allows that.
	</t>		</t>
	<t>		<t>
	The WANT_DELEGATION operation may be performed on any type of		The WANT_DELEGATION operation may be performed on any type of
	file object other than a directory.		file object other than a directory.
	</t>		</t>
	<t>		<t>
	When a delegation is obtained using WANT_DELEGATION, any open		When a delegation is obtained using WANT_DELEGATION, any open
	files for the same filehandle held by that client are to be		files for the same filehandle held by that client are to be
	treated as subordinate to the delegation, just as if they had		treated as subordinate to the delegation, just as if they had
	been created using an OPEN of type CLAIM_DELEGATE_CUR. They are		been created using an OPEN of type CLAIM_DELEGATE_CUR. They are
	otherwise unchanged as to seqid, access and deny modes, and the		otherwise unchanged as to seqid, access and deny modes, and the
	relationship with byte-range locks. Similarly, because		relationship with byte-range locks. Similarly, because
	existing byte-range		existing byte-range
	locks are subordinate to an open, those byte-range locks also become		locks are subordinate to an open, those byte-range locks also become
	indirectly subordinate to that new delegation.		indirectly subordinate to that new delegation.
	</t>		</t>
	<t>		<t>
	The WANT_DELEGATION operation provides for delivery of delegations		The WANT_DELEGATION operation provides for delivery of delegations
	via callbacks, when the delegations are not immediately available.		via callbacks, when the delegations are not immediately available.
	When a requested delegation is available, it is delivered to the		When a requested delegation is available, it is delivered to the
	client via a CB_PUSH_DELEG operation. When this happens, open files		client via a CB_PUSH_DELEG operation. When this happens, open files
	for the same filehandle become subordinate to the new delegation		for the same filehandle become subordinate to the new delegation
	at the point at which the delegation is delivered, just as if they had		at the point at which the delegation is delivered, just as if they had
	been created using an OPEN of type CLAIM_DELEGATE_CUR.		been created using an OPEN of type CLAIM_DELEGATE_CUR.
	Similarly, this occurs for existing byte-range locks subordinate to an o pen.		Similarly, this occurs for existing byte-range locks subordinate to an o pen.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section title="Data Caching and Revocation" anchor="data_caching_revocation"		<section anchor="data_caching_revocation" numbered="true" toc="default">
	>		<name>Data Caching and Revocation</name>
	<t>		<t>
	When locks and delegations are revoked, the assumptions upon which		When locks and delegations are revoked, the assumptions upon which
	successful caching depends are no longer guaranteed. For any locks or		successful caching depends are no longer guaranteed. For any locks or
	share reservations that have been revoked, the corresponding state-owner		share reservations that have been revoked, the corresponding state-owner
	needs to be notified. This notification includes applications with a		needs to be notified. This notification includes applications with a
	file open that has a corresponding delegation that has been revoked.		file open that has a corresponding delegation that has been revoked.
	Cached data associated with the revocation must be removed from the		Cached data associated with the revocation must be removed from the
	client. In the case of modified data existing in the client's cache,		client. In the case of modified data existing in the client's cache,
	that data must be removed from the client without being written to		that data must be removed from the client without being written to
	the server. As mentioned, the assumptions made by the client are no		the server. As mentioned, the assumptions made by the client are no
	longer valid at the point when a lock or delegation has been revoked.		longer valid at the point when a lock or delegation has been revoked.
	For example, another client may have been granted a conflicting byte-range lock		For example, another client may have been granted a conflicting byte-range lock
	after the revocation of the byte-range lock at the first client. Therefor e, the		after the revocation of the byte-range lock at the first client. Therefor e, the
	data within the lock range may have been modified by the other client.		data within the lock range may have been modified by the other client.
	Obviously, the first client is unable to guarantee to the application		Obviously, the first client is unable to guarantee to the application
	what has occurred to the file in the case of revocation.		what has occurred to the file in the case of revocation.
	</t>		</t>
	<t>		<t>
	Notification to a state-owner will in many cases consist of simply		Notification to a state-owner will in many cases consist of simply
	returning an error on the next and all subsequent READs/WRITEs to the		returning an error on the next and all subsequent READs/WRITEs to the
	open file or on the close. Where the methods available to a client		open file or on the close. Where the methods available to a client
	make such notification impossible because errors for certain		make such notification impossible because errors for certain
	operations may not be returned, more drastic action such as signals or		operations may not be returned, more drastic action such as signals or
	process termination may be appropriate. The justification here is		process termination may be appropriate. The justification here is
	that an invariant on which an application depends may be violated.		that an invariant on which an application depends may be violated.
	Depending on how errors are typically treated for the client-operating		Depending on how errors are typically treated for the client-operating
	environment, further levels of notification including logging, console		environment, further levels of notification including logging, console
	messages, and GUI pop-ups may be appropriate.		messages, and GUI pop-ups may be appropriate.
	</t>		</t>
	<section title="Revocation Recovery for Write Open Delegation"		<section anchor="revocation_recovery_write" numbered="true" toc="default
	anchor="revocation_recovery_write" >		">
	<t>		<name>Revocation Recovery for Write Open Delegation</name>
			<t>
	Revocation recovery for an OPEN_DELEGATE_WRITE delegation poses the spec ial		Revocation recovery for an OPEN_DELEGATE_WRITE delegation poses the spec ial
	issue of modified data in the client cache while the file is not open.		issue of modified data in the client cache while the file is not open.
	In this situation, any client that does not flush modified data to		In this situation, any client that does not flush modified data to
	the server on each close must ensure that the user receives		the server on each close must ensure that the user receives
	appropriate notification of the failure as a result of the revocation.		appropriate notification of the failure as a result of the revocation.
	Since such situations may require human action to correct problems,		Since such situations may require human action to correct problems,
	notification schemes in which the appropriate user or administrator is		notification schemes in which the appropriate user or administrator is
	notified may be necessary. Logging and console messages are typical		notified may be necessary. Logging and console messages are typical
	examples.		examples.
	</t>		</t>
	<t>		<t>
	If there is modified data on the client, it must not be flushed		If there is modified data on the client, it must not be flushed
	normally to the server. A client may attempt to provide a copy of the		normally to the server. A client may attempt to provide a copy of the
	file data as modified during the delegation under a different name in		file data as modified during the delegation under a different name in
	the file system namespace to ease recovery. Note that when the		the file system namespace to ease recovery. Note that when the
	client can determine that the file has not been modified by any other		client can determine that the file has not been modified by any other
	client, or when the client has a complete cached copy of the file in		client, or when the client has a complete cached copy of the file in
	question, such a saved copy of the client's view of the file may be of		question, such a saved copy of the client's view of the file may be of
	particular value for recovery. In another case, recovery using a copy		particular value for recovery. In another case, recovery using a copy
	of the file based partially on the client's cached data and partially		of the file based partially on the client's cached data and partially
	on the server's copy as modified by other clients will be anything but		on the server's copy as modified by other clients will be anything but
	straightforward, so clients may avoid saving file contents in these		straightforward, so clients may avoid saving file contents in these
	situations or specially mark the results to warn users of possible		situations or specially mark the results to warn users of possible
	problems.		problems.
	</t>		</t>
	<t>		<t>
	Saving of such modified data in delegation revocation situations		Saving of such modified data in delegation revocation situations
	may be limited to files of a certain size or might be used only when		may be limited to files of a certain size or might be used only when
	sufficient disk space is available within the target file system.		sufficient disk space is available within the target file system.
	Such saving may also be restricted to situations when the client has		Such saving may also be restricted to situations when the client has
	sufficient buffering resources to keep the cached copy available		sufficient buffering resources to keep the cached copy available
	until it is properly stored to the target file system.		until it is properly stored to the target file system.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section title="Attribute Caching" >		<section numbered="true" toc="default">
	<t>		<name>Attribute Caching</name>
			<t>
	This section pertains to the caching of a file's attributes on a client		This section pertains to the caching of a file's attributes on a client
	when that client does not hold a delegation on the file.		when that client does not hold a delegation on the file.
	</t>		</t>
			<t>
	<t>
	The attributes discussed in this section do not include named		The attributes discussed in this section do not include named
	attributes. Individual named attributes are analogous to files, and		attributes. Individual named attributes are analogous to files, and
	caching of the data for these needs to be handled just as data caching		caching of the data for these needs to be handled just as data caching
	is for ordinary files. Similarly, LOOKUP results from an OPENATTR		is for ordinary files. Similarly, LOOKUP results from an OPENATTR
	directory (as well as the directory's contents) are to be cached on		directory (as well as the directory's contents) are to be cached on
	the same basis as any other pathnames.		the same basis as any other pathnames.
	</t>		</t>
	<t>		<t>
	Clients may cache file attributes obtained from the server and use		Clients may cache file attributes obtained from the server and use
	them to avoid subsequent GETATTR requests. Such caching is write		them to avoid subsequent GETATTR requests. Such caching is write
	through in that modification to file attributes is always done by		through in that modification to file attributes is always done by
	means of requests to the server and should not be done locally and		means of requests to the server and should not be done locally and
	should not be cached. The exception to this are modifications to attribut es that		should not be cached. The exception to this are modifications to attribut es that
	are intimately connected with data caching. Therefore, extending a		are intimately connected with data caching. Therefore, extending a
	file by writing data to the local data cache is reflected immediately		file by writing data to the local data cache is reflected immediately
	in the size as seen on the client without this change being		in the size as seen on the client without this change being
	immediately reflected on the server. Normally, such changes are not		immediately reflected on the server. Normally, such changes are not
	propagated directly to the server, but when the modified data is		propagated directly to the server, but when the modified data is
	flushed to the server, analogous attribute changes are made on the		flushed to the server, analogous attribute changes are made on the
	server. When OPEN delegation is in effect, the modified attributes		server. When OPEN delegation is in effect, the modified attributes
	may be returned to the server in reaction to a CB_RECALL call.		may be returned to the server in reaction to a CB_RECALL call.
	</t>		</t>
	<t>		<t>
	The result of local caching of attributes is that the attribute		The result of local caching of attributes is that the attribute
	caches maintained on individual clients will not be coherent.		caches maintained on individual clients will not be coherent.
	Changes made in one order on the server may be seen in a different		Changes made in one order on the server may be seen in a different
	order on one client and in a third order on another client.		order on one client and in a third order on another client.
	</t>		</t>
	<t>		<t>
	The typical file system application programming interfaces do not		The typical file system application programming interfaces do not
	provide means to atomically modify or interrogate attributes for		provide means to atomically modify or interrogate attributes for
	multiple files at the same time. The following rules provide an		multiple files at the same time. The following rules provide an
	environment where the potential incoherencies mentioned above can be		environment where the potential incoherencies mentioned above can be
	reasonably managed. These rules are derived from the practice of		reasonably managed. These rules are derived from the practice of
	previous NFS protocols.		previous NFS protocols.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	All attributes for a given file (per-fsid attributes excepted) are		All attributes for a given file (per-fsid attributes excepted) are
	cached as a unit at the client so that no non-serializability can		cached as a unit at the client so that no non-serializability can
	arise within the context of a single file.		arise within the context of a single file.
	</t>		</li>
	<t>		<li>
	An upper time boundary is maintained on how long a client cache entry		An upper time boundary is maintained on how long a client cache entry
	can be kept without being refreshed from the server.		can be kept without being refreshed from the server.
	</t>		</li>
	<t>		<li>
	When operations are performed that change attributes at the server,		When operations are performed that change attributes at the server,
	the updated attribute set is requested as part of the containing RPC.		the updated attribute set is requested as part of the containing RPC.
	This includes directory operations that update attributes indirectly.		This includes directory operations that update attributes indirectly.
	This is accomplished by following the modifying operation with a		This is accomplished by following the modifying operation with a
	GETATTR operation and then using the results of the GETATTR to update		GETATTR operation and then using the results of the GETATTR to update
	the client's cached attributes.		the client's cached attributes.
	</t>		</li>
	</list>		</ul>
			<t>
	Note that if the full set of attributes to be cached is requested by		Note that if the full set of attributes to be cached is requested by
	READDIR, the results can be cached by the client on the same basis as		READDIR, the results can be cached by the client on the same basis as
	attributes obtained via GETATTR.		attributes obtained via GETATTR.
	</t>		</t>
	<t>		<t>
	A client may validate its cached version of attributes for a file by		A client may validate its cached version of attributes for a file by
	fetching both the change and time_access attributes and assuming		fetching both the change and time_access attributes and assuming
	that if the change attribute has the same value as it did when the		that if the change attribute has the same value as it did when the
	attributes were cached, then no attributes other than time_access have		attributes were cached, then no attributes other than time_access have
	changed. The reason why time_access is also fetched is because many		changed. The reason why time_access is also fetched is because many
	servers operate in environments where the operation that updates		servers operate in environments where the operation that updates
	change does not update time_access. For example, POSIX file semantics		change does not update time_access. For example, POSIX file semantics
	do not update access time when a file is modified by the write system		do not update access time when a file is modified by the write system
	call <xref target="write_atime"/>. Therefore, the client that wants a cur rent time_access value		call <xref target="write_atime" format="default"/>. Therefore, the client that wants a current time_access value
	should fetch it with change during the attribute cache validation		should fetch it with change during the attribute cache validation
	processing and update its cached time_access.		processing and update its cached time_access.
	</t>		</t>
	<t>		<t>
	The client may maintain a cache of modified attributes for those		The client may maintain a cache of modified attributes for those
	attributes intimately connected with data of modified regular files		attributes intimately connected with data of modified regular files
	(size, time_modify, and change). Other than those three attributes,		(size, time_modify, and change). Other than those three attributes,
	the client MUST NOT maintain a cache of modified attributes. Instead,		the client <bcp14>MUST NOT</bcp14> maintain a cache of modified attributes . Instead,
	attribute changes are immediately sent to the server.		attribute changes are immediately sent to the server.
	</t>		</t>
	<t>		<t>
	In some operating environments, the equivalent to time_access is		In some operating environments, the equivalent to time_access is
	expected to be implicitly updated by each read of the content of the		expected to be implicitly updated by each read of the content of the
	file object. If an NFS client is caching the content of a file		file object. If an NFS client is caching the content of a file
	object, whether it is a regular file, directory, or symbolic link, the		object, whether it is a regular file, directory, or symbolic link, the
	client SHOULD NOT update the time_access attribute (via SETATTR or a		client <bcp14>SHOULD NOT</bcp14> update the time_access attribute (via SET ATTR or a
	small READ or READDIR request) on the server with each read that is		small READ or READDIR request) on the server with each read that is
	satisfied from cache. The reason is that this can defeat the		satisfied from cache. The reason is that this can defeat the
	performance benefits of caching content, especially since an explicit		performance benefits of caching content, especially since an explicit
	SETATTR of time_access may alter the change attribute on the server.		SETATTR of time_access may alter the change attribute on the server.
	If the change attribute changes, clients that are caching the content		If the change attribute changes, clients that are caching the content
	will think the content has changed, and will re-read unmodified data		will think the content has changed, and will re-read unmodified data
	from the server. Nor is the client encouraged to maintain a modified		from the server. Nor is the client encouraged to maintain a modified
	version of time_access in its cache, since the client either would		version of time_access in its cache, since the client either would
	eventually have to write the access time to the server		eventually have to write the access time to the server
	with bad performance effects or never update the		with bad performance effects or never update the
	server's time_access, thereby resulting in a situation where an		server's time_access, thereby resulting in a situation where an
	application that caches access time between a close and open of		application that caches access time between a close and open of
	the same file observes the access time oscillating between the past and		the same file observes the access time oscillating between the past and
	present. The time_access attribute always means the time of last		present. The time_access attribute always means the time of last
	access to a file by a read that was satisfied by the server. This way		access to a file by a read that was satisfied by the server. This way
	clients will tend to see only time_access changes that go forward in		clients will tend to see only time_access changes that go forward in
	time.		time.
	</t>		</t>
	</section>		</section>
	<section title="Data and Metadata Caching and Memory Mapped Files" >		<section numbered="true" toc="default">
	<t>		<name>Data and Metadata Caching and Memory Mapped Files</name>
			<t>
	Some operating environments include the capability for an application		Some operating environments include the capability for an application
	to map a file's content into the application's address space. Each		to map a file's content into the application's address space. Each
	time the application accesses a memory location that corresponds to a		time the application accesses a memory location that corresponds to a
	block that has not been loaded into the address space, a page fault		block that has not been loaded into the address space, a page fault
	occurs and the file is read (or if the block does not exist in the		occurs and the file is read (or if the block does not exist in the
	file, the block is allocated and then instantiated in the		file, the block is allocated and then instantiated in the
	application's address space).		application's address space).
	</t>		</t>
	<t>		<t>
	As long as each memory-mapped access to the file requires a page		As long as each memory-mapped access to the file requires a page
	fault, the relevant attributes of the file that are used to detect		fault, the relevant attributes of the file that are used to detect
	access and modification (time_access, time_metadata, time_modify, and		access and modification (time_access, time_metadata, time_modify, and
	change) will be updated. However, in many operating environments,		change) will be updated. However, in many operating environments,
	when page faults are not required, these attributes will not be updated		when page faults are not required, these attributes will not be updated
	on reads or updates to the file via memory access (regardless of		on reads or updates to the file via memory access (regardless of
	whether the file is local or is accessed remotely). A client or		whether the file is local or is accessed remotely). A client or
	server MAY fail to update attributes of a file that is being accessed		server <bcp14>MAY</bcp14> fail to update attributes of a file that is bein g accessed
	via memory-mapped I/O. This has several implications:		via memory-mapped I/O. This has several implications:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	If there is an application on the server that has memory mapped a file		If there is an application on the server that has memory mapped a file
	that a client is also accessing, the client may not be able to get a		that a client is also accessing, the client may not be able to get a
	consistent value of the change attribute to determine		consistent value of the change attribute to determine
	whether or not its cache is stale. A server that knows that		whether or not its cache is stale. A server that knows that
	the file is memory-mapped could always pessimistically		the file is memory-mapped could always pessimistically
	return updated values for change so as to force the		return updated values for change so as to force the
	application to always get the most up-to-date data		application to always get the most up-to-date data
	and metadata for the file. However, due to the negative performance		and metadata for the file. However, due to the negative performance
	implications of this, such behavior is OPTIONAL.		implications of this, such behavior is <bcp14>OPTIONAL</bcp14>.
	</t>		</li>
	<t>		<li>
	If the memory-mapped file is not being modified on the server, and		If the memory-mapped file is not being modified on the server, and
	instead is just being read by an application via the memory-mapped		instead is just being read by an application via the memory-mapped
	interface, the client will not see an updated time_access attribute.		interface, the client will not see an updated time_access attribute.
	However, in many operating environments, neither will any process		However, in many operating environments, neither will any process
	running on the server. Thus, NFS clients are at no disadvantage with		running on the server. Thus, NFS clients are at no disadvantage with
	respect to local processes.		respect to local processes.
	</t>		</li>
	<t>		<li>
	If there is another client that is memory mapping the file, and if		If there is another client that is memory mapping the file, and if
	that client is holding an OPEN_DELEGATE_WRITE delegation, the same set of issues as		that client is holding an OPEN_DELEGATE_WRITE delegation, the same set of issues as
	discussed in the previous two bullet points apply. So, when a server		discussed in the previous two bullet points apply. So, when a server
	does a CB_GETATTR to a file that the client has modified in its cache,		does a CB_GETATTR to a file that the client has modified in its cache,
	the reply from CB_GETATTR will not necessarily be accurate. As		the reply from CB_GETATTR will not necessarily be accurate. As
	discussed earlier, the client's obligation is to report that the file		discussed earlier, the client's obligation is to report that the file
	has been modified since the delegation was granted, not whether it has		has been modified since the delegation was granted, not whether it has
	been modified again between successive CB_GETATTR calls, and the		been modified again between successive CB_GETATTR calls, and the
	server MUST assume that any file the client has modified in cache has		server <bcp14>MUST</bcp14> assume that any file the client has modifie d in cache has
	been modified again between successive CB_GETATTR calls. Depending on		been modified again between successive CB_GETATTR calls. Depending on
	the nature of the client's memory management system, this weak		the nature of the client's memory management system, this weak
	obligation may not be possible. A client MAY return stale information		obligation may not be possible. A client <bcp14>MAY</bcp14> return st ale information
	in CB_GETATTR whenever the file is memory-mapped.		in CB_GETATTR whenever the file is memory-mapped.
	</t>		</li>
	<t>		<li>
			<t>
	The mixture of memory mapping and byte-range locking on the same file is		The mixture of memory mapping and byte-range locking on the same file is
	problematic. Consider the following scenario, where a page size on		problematic. Consider the following scenario, where a page size on
	each client is 8192 bytes.		each client is 8192 bytes.
	<list style="symbols">
	<t>
	Client A memory maps the first page (8192 bytes) of file X.
	</t>		</t>
	<t>		<ul spacing="normal">
			<li>
			Client A memory maps the first page (8192 bytes) of file X.
			</li>
			<li>
	Client B memory maps the first page (8192 bytes) of file X.		Client B memory maps the first page (8192 bytes) of file X.
	</t>		</li>
	<t>		<li>
	Client A WRITE_LT locks the first 4096 bytes.		Client A WRITE_LT locks the first 4096 bytes.
	</t>		</li>
	<t>		<li>
	Client B WRITE_LT locks the second 4096 bytes.		Client B WRITE_LT locks the second 4096 bytes.
	</t>		</li>
	<t>		<li>
	Client A, via a STORE instruction, modifies part of its locked byt e-range.		Client A, via a STORE instruction, modifies part of its locked byt e-range.
	</t>		</li>
	<t>		<li>
	Simultaneous to client A, client B executes a STORE on part of its		Simultaneous to client A, client B executes a STORE on part of its
	locked byte-range.		locked byte-range.
	</t>		</li>
	</list>		</ul>
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Here the challenge is for each client to resynchronize to get a		Here the challenge is for each client to resynchronize to get a
	correct view of the first page. In many operating environments, the		correct view of the first page. In many operating environments, the
	virtual memory management systems on each client only know a page is		virtual memory management systems on each client only know a page is
	modified, not that a subset of the page corresponding to the		modified, not that a subset of the page corresponding to the
	respective lock byte-ranges has been modified. So it is not possible for		respective lock byte-ranges has been modified. So it is not possible for
	each client to do the right thing, which is to write to the		each client to do the right thing, which is to write to the
	server only that portion of the page that is locked. For example, if		server only that portion of the page that is locked. For example, if
	client A simply writes out the page, and then client B writes out the		client A simply writes out the page, and then client B writes out the
	page, client A's data is lost.		page, client A's data is lost.
	</t>		</t>
	<t>		<t>
	Moreover, if mandatory locking is enabled on the file, then we have a		Moreover, if mandatory locking is enabled on the file, then we have a
	different problem. When clients A and B execute the STORE instructions,		different problem. When clients A and B execute the STORE instructions,
	the resulting page faults require a byte-range lock on the entire page.		the resulting page faults require a byte-range lock on the entire page.
	Each client then tries to extend their locked range to the entire		Each client then tries to extend their locked range to the entire
	page, which results in a deadlock. Communicating the NFS4ERR_DEADLOCK		page, which results in a deadlock. Communicating the NFS4ERR_DEADLOCK
	error to a STORE instruction is difficult at best.		error to a STORE instruction is difficult at best.
	</t>		</t>
	<t>		<t>
	If a client is locking the entire memory-mapped file, there is no		If a client is locking the entire memory-mapped file, there is no
	problem with advisory or mandatory byte-range locking, at least until the		problem with advisory or mandatory byte-range locking, at least until the
	client unlocks a byte-range in the middle of the file.		client unlocks a byte-range in the middle of the file.
	</t>
	<t>
	Given the above issues, the following are permitted:
	<list style="symbols">
	<t>
	Clients and servers MAY deny memory mapping a file for which they know
	there are
	byte-range locks.
	</t>		</t>
	<t>		<t>
	Clients and servers MAY deny a byte-range lock on a file they know is		Given the above issues, the following are permitted:
	memory-mapped.
	</t>		</t>
	<t>		<ul spacing="normal">
	A client MAY deny memory mapping a file that it knows requires		<li>
			Clients and servers <bcp14>MAY</bcp14> deny memory mapping a file for
			which they know there are
			byte-range locks.
			</li>
			<li>
			Clients and servers <bcp14>MAY</bcp14> deny a byte-range lock on a fil
			e they know is
			memory-mapped.
			</li>
			<li>
			A client <bcp14>MAY</bcp14> deny memory mapping a file that it knows r
			equires
	mandatory locking for I/O. If mandatory locking is enabled after the		mandatory locking for I/O. If mandatory locking is enabled after the
	file is opened and mapped, the client MAY deny the application further		file is opened and mapped, the client <bcp14>MAY</bcp14> deny the appl ication further
	access to its mapped file.		access to its mapped file.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section anchor="without_dir_deleg" numbered="true" toc="default">
	<section title="Name and Directory Caching without Directory Delegations"		<name>Name and Directory Caching without Directory Delegations</name>
	anchor="without_dir_deleg">		<t>
	<t>
	The NFSv4.1 directory delegation facility		The NFSv4.1 directory delegation facility
	(described in <xref target="dir_deleg" /> below) is OPTIONAL		(described in <xref target="dir_deleg" format="default"/> below) is <bcp14 >OPTIONAL</bcp14>
	for servers to implement. Even where it is		for servers to implement. Even where it is
	implemented, it may not always be functional because of resource		implemented, it may not always be functional because of resource
	availability issues or other constraints. Thus, it is		availability issues or other constraints. Thus, it is
	important to understand how name and directory caching are done		important to understand how name and directory caching are done
	in the absence of directory delegations. These topics are		in the absence of directory delegations. These topics are
	discussed in the next two subsections.		discussed in the next two subsections.
	</t>		</t>
	<section anchor="name_caching" title="Name Caching" >		<section anchor="name_caching" numbered="true" toc="default">
	<t>		<name>Name Caching</name>
			<t>
	The results of LOOKUP and READDIR operations may be cached to avoid		The results of LOOKUP and READDIR operations may be cached to avoid
	the cost of subsequent LOOKUP operations. Just as in the case of		the cost of subsequent LOOKUP operations. Just as in the case of
	attribute caching, inconsistencies may arise among the various client		attribute caching, inconsistencies may arise among the various client
	caches. To mitigate the effects of these inconsistencies and given		caches. To mitigate the effects of these inconsistencies and given
	the context of typical file system APIs, an upper time boundary is		the context of typical file system APIs, an upper time boundary is
	maintained for how long a client name cache entry can be kept without		maintained for how long a client name cache entry can be kept without
	verifying that the entry has not been made invalid by a directory		verifying that the entry has not been made invalid by a directory
	change operation performed by another client.		change operation performed by another client.
	</t>		</t>
	<t>		<t>
	When a client is not making changes to a directory for which there		When a client is not making changes to a directory for which there
	exist name cache entries, the client needs to periodically fetch		exist name cache entries, the client needs to periodically fetch
	attributes for that directory to ensure that it is not being modified.		attributes for that directory to ensure that it is not being modified.
	After determining that no modification has occurred, the expiration		After determining that no modification has occurred, the expiration
	time for the associated name cache entries may be updated to be the		time for the associated name cache entries may be updated to be the
	current time plus the name cache staleness bound.		current time plus the name cache staleness bound.
	</t>		</t>
	<t>		<t>
	When a client is making changes to a given directory, it needs to		When a client is making changes to a given directory, it needs to
	determine whether there have been changes made to the directory by		determine whether there have been changes made to the directory by
	other clients. It does this by using the change attribute as reported		other clients. It does this by using the change attribute as reported
	before and after the directory operation in the associated		before and after the directory operation in the associated
	change_info4 value returned for the operation. The server is able to		change_info4 value returned for the operation. The server is able to
	communicate to the client whether the change_info4 data is provided		communicate to the client whether the change_info4 data is provided
	atomically with respect to the directory operation. If the change		atomically with respect to the directory operation. If the change
	values are provided atomically, the client has a basis for determining,		values are provided atomically, the client has a basis for determining,
	given proper care, whether other clients are modifying the directory		given proper care, whether other clients are modifying the directory
	in question.		in question.
	</t>		</t>
	<t>		<t>
	The simplest way to enable the client to make this determination is		The simplest way to enable the client to make this determination is
	for the client to serialize all changes made to a specific directory.		for the client to serialize all changes made to a specific directory.
	When this is done, and the server provides before and after values of th e		When this is done, and the server provides before and after values of th e
	change attribute atomically, the client can simply compare the		change attribute atomically, the client can simply compare the
	after value of the change attribute from one operation on a		after value of the change attribute from one operation on a
	directory with the before value on the subsequent operation		directory with the before value on the subsequent operation
	modifying that directory. When these are equal, the client is		modifying that directory. When these are equal, the client is
	assured that no other client is modifying the directory in question.		assured that no other client is modifying the directory in question.
	</t>		</t>
	<t>		<t>
	When such serialization is not used, and there may be multiple		When such serialization is not used, and there may be multiple
	simultaneous outstanding operations modifying a single directory sent		simultaneous outstanding operations modifying a single directory sent
	from a single client, making this sort of determination can be more		from a single client, making this sort of determination can be more
	complicated. If two such operations		complicated. If two such operations
	complete in a different order than they were actually performed,		complete in a different order than they were actually performed,
	that might give an appearance consistent with modification being		that might give an appearance consistent with modification being
	made by another client. Where this appears to happen, the client		made by another client. Where this appears to happen, the client
	needs to await the completion of all such modifications that were		needs to await the completion of all such modifications that were
	started previously, to see if the outstanding before and after		started previously, to see if the outstanding before and after
	change numbers can be sorted into a chain such that the before		change numbers can be sorted into a chain such that the before
	value of one change number matches the after value of a previous		value of one change number matches the after value of a previous
	one, in a chain consistent with this client being the only one		one, in a chain consistent with this client being the only one
	modifying the directory.		modifying the directory.
	</t>		</t>
	<t>		<t>
	In either of these cases, the client is able to determine whether		In either of these cases, the client is able to determine whether
	the directory is being modified by another client.		the directory is being modified by another client.
	If the comparison indicates that the directory was updated by		If the comparison indicates that the directory was updated by
	another client, the name cache associated with the modified directory		another client, the name cache associated with the modified directory
	is purged from the client. If the comparison indicates no		is purged from the client. If the comparison indicates no
	modification, the name cache can be updated on the client to reflect		modification, the name cache can be updated on the client to reflect
	the directory operation and the associated timeout can be extended. The		the directory operation and the associated timeout can be extended. The
	post-operation change value needs to be saved as the basis for future		post-operation change value needs to be saved as the basis for future
	change_info4 comparisons.		change_info4 comparisons.
	</t>		</t>
	<t>		<t>
	As demonstrated by the scenario above, name caching requires that the		As demonstrated by the scenario above, name caching requires that the
	client revalidate name cache data by inspecting the change attribute		client revalidate name cache data by inspecting the change attribute
	of a directory at the point when the name cache item was cached. This		of a directory at the point when the name cache item was cached. This
	requires that the server update the change attribute for directories		requires that the server update the change attribute for directories
	when the contents of the corresponding directory is modified. For a		when the contents of the corresponding directory is modified. For a
	client to use the change_info4 information appropriately and		client to use the change_info4 information appropriately and
	correctly, the server must report the pre- and post-operation change		correctly, the server must report the pre- and post-operation change
	attribute values atomically. When the server is unable to report the		attribute values atomically. When the server is unable to report the
	before and after values atomically with respect to the directory		before and after values atomically with respect to the directory
	operation, the server must indicate that fact in the change_info4		operation, the server must indicate that fact in the change_info4
	return value. When the information is not atomically reported, the		return value. When the information is not atomically reported, the
	client should not assume that other clients have not changed the		client should not assume that other clients have not changed the
	directory.		directory.
	</t>		</t>
	</section>		</section>
	<section title="Directory Caching" >		<section numbered="true" toc="default">
	<t>		<name>Directory Caching</name>
			<t>
	The results of READDIR operations may be used to avoid subsequent		The results of READDIR operations may be used to avoid subsequent
	READDIR operations. Just as in the cases of attribute and name		READDIR operations. Just as in the cases of attribute and name
	caching, inconsistencies may arise among the various client caches. To		caching, inconsistencies may arise among the various client caches. To
	mitigate the effects of these inconsistencies, and given the context of		mitigate the effects of these inconsistencies, and given the context of
	typical file system APIs, the following rules should be followed:		typical file system APIs, the following rules should be followed:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Cached READDIR information for a directory that is not obtained in a		Cached READDIR information for a directory that is not obtained in a
	single READDIR operation must always be a consistent snapshot of		single READDIR operation must always be a consistent snapshot of
	directory contents. This is determined by using a GETATTR before th e		directory contents. This is determined by using a GETATTR before th e
	first READDIR and after the last READDIR that contributes to the		first READDIR and after the last READDIR that contributes to the
	cache.		cache.
	</t>		</li>
	<t>		<li>
	An upper time boundary is maintained to indicate the length of time a		An upper time boundary is maintained to indicate the length of time a
	directory cache entry is considered valid before the client must		directory cache entry is considered valid before the client must
	revalidate the cached information.		revalidate the cached information.
	</t>		</li>
	</list>		</ul>
			<t>
	The revalidation technique parallels that discussed in the case of		The revalidation technique parallels that discussed in the case of
	name caching. When the client is not changing the directory in		name caching. When the client is not changing the directory in
	question, checking the change attribute of the directory with GETATTR		question, checking the change attribute of the directory with GETATTR
	is adequate. The lifetime of the cache entry can be extended at these		is adequate. The lifetime of the cache entry can be extended at these
	checkpoints. When a client is modifying the directory, the client		checkpoints. When a client is modifying the directory, the client
	needs to use the change_info4 data to determine whether there are		needs to use the change_info4 data to determine whether there are
	other clients modifying the directory. If it is determined that no		other clients modifying the directory. If it is determined that no
	other client modifications are occurring, the client may update its		other client modifications are occurring, the client may update its
	directory cache to reflect its own changes.		directory cache to reflect its own changes.
	</t>		</t>
	<t>		<t>
	As demonstrated previously, directory caching requires that the client		As demonstrated previously, directory caching requires that the client
	revalidate directory cache data by inspecting the change attribute of		revalidate directory cache data by inspecting the change attribute of
	a directory at the point when the directory was cached. This requires		a directory at the point when the directory was cached. This requires
	that the server update the change attribute for directories when the		that the server update the change attribute for directories when the
	contents of the corresponding directory is modified. For a client to		contents of the corresponding directory is modified. For a client to
	use the change_info4 information appropriately and correctly, the		use the change_info4 information appropriately and correctly, the
	server must report the pre- and post-operation change attribute values		server must report the pre- and post-operation change attribute values
	atomically. When the server is unable to report the before and after		atomically. When the server is unable to report the before and after
	values atomically with respect to the directory operation, the server		values atomically with respect to the directory operation, the server
	must indicate that fact in the change_info4 return value. When the		must indicate that fact in the change_info4 return value. When the
	information is not atomically reported, the client should not assume		information is not atomically reported, the client should not assume
	that other clients have not changed the directory.		that other clients have not changed the directory.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section title="Directory Delegations" anchor="dir_deleg">		<section anchor="dir_deleg" numbered="true" toc="default">
	<section title="Introduction to Directory Delegations">		<name>Directory Delegations</name>
	<t>		<section numbered="true" toc="default">
			<name>Introduction to Directory Delegations</name>
			<t>
	Directory caching for the NFSv4.1 protocol, as previously		Directory caching for the NFSv4.1 protocol, as previously
	described, is similar to file		described, is similar to file
	caching in previous versions. Clients typically cache		caching in previous versions. Clients typically cache
	directory information for		directory information for
	a duration determined by the client. At the end of a predefined		a duration determined by the client. At the end of a predefined
	timeout, the client will query the server to see if the directory has		timeout, the client will query the server to see if the directory has
	been updated. By caching attributes, clients reduce the number of		been updated. By caching attributes, clients reduce the number of
	GETATTR calls made to the server to validate attributes. Furthermore,		GETATTR calls made to the server to validate attributes. Furthermore,
	frequently accessed files and directories, such as the current		frequently accessed files and directories, such as the current
	working directory, have their attributes cached on the client so that		working directory, have their attributes cached on the client so that
	some NFS operations can be performed without having to make an RPC		some NFS operations can be performed without having to make an RPC
	call. By caching name and inode information about most recently		call. By caching name and inode information about most recently
	looked up entries in a Directory Name Lookup Cache (DNLC), clients do		looked up entries in a Directory Name Lookup Cache (DNLC), clients do
	not need to send LOOKUP calls to the server every time these files		not need to send LOOKUP calls to the server every time these files
	are accessed.		are accessed.
	</t>		</t>
	<t>		<t>
	This caching approach works reasonably well at reducing network		This caching approach works reasonably well at reducing network
	traffic in many environments. However, it does not address		traffic in many environments. However, it does not address
	environments where there are numerous queries for files that do not		environments where there are numerous queries for files that do not
	exist. In these cases of "misses", the client sends requests to		exist. In these cases of "misses", the client sends requests to
	the server in order to provide reasonable application semantics and		the server in order to provide reasonable application semantics and
	promptly detect the creation of new directory entries. Examples of		promptly detect the creation of new directory entries. Examples of
	high miss activity are compilation in software development		high miss activity are compilation in software development
	environments. The current behavior of NFS limits its potential		environments. The current behavior of NFS limits its potential
	scalability and wide-area sharing effectiveness in these types of		scalability and wide-area sharing effectiveness in these types of
	environments. Other distributed stateful file system architectures		environments. Other distributed stateful file system architectures
	such as AFS and DFS have proven that adding state around directory		such as AFS and DFS have proven that adding state around directory
	contents can greatly reduce network traffic in high-miss		contents can greatly reduce network traffic in high-miss
	environments.		environments.
	</t>		</t>
	<t>		<t>
	Delegation of directory contents is an OPTIONAL feature of NFSv4.1.		Delegation of directory contents is an <bcp14>OPTIONAL</bcp14> feature o
			f NFSv4.1.
	Directory delegations provide similar traffic reduction		Directory delegations provide similar traffic reduction
	benefits as with file delegations. By allowing clients to cache		benefits as with file delegations. By allowing clients to cache
	directory contents (in a read-only fashion) while being notified of		directory contents (in a read-only fashion) while being notified of
	changes, the client can avoid making frequent requests to interrogate		changes, the client can avoid making frequent requests to interrogate
	the contents of slowly-changing directories, reducing network traffic		the contents of slowly-changing directories, reducing network traffic
	and improving client performance. It can also simplify the task of		and improving client performance. It can also simplify the task of
	determining whether other clients are making changes to the directory		determining whether other clients are making changes to the directory
	when the client itself is making many changes to the directory and		when the client itself is making many changes to the directory and
	changes are not serialized.		changes are not serialized.
	</t>		</t>
	<t>		<t>
	Directory delegations allow improved namespace cache consistency to be		Directory delegations allow improved namespace cache consistency to be
	achieved through delegations and synchronous recalls, in the absence		achieved through delegations and synchronous recalls, in the absence
	of notifications. In addition, if time-based consistency is		of notifications. In addition, if time-based consistency is
	sufficient, asynchronous notifications can provide performance		sufficient, asynchronous notifications can provide performance
	benefits for the client, and possibly the server, under some common		benefits for the client, and possibly the server, under some common
	operating conditions such as slowly-changing and/or very large		operating conditions such as slowly-changing and/or very large
	directories.		directories.
	</t>		</t>
	</section>		</section>
	<section title="Directory Delegation Design">		<section numbered="true" toc="default">
	<t>		<name>Directory Delegation Design</name>
			<t>
	NFSv4.1 introduces the GET_DIR_DELEGATION		NFSv4.1 introduces the GET_DIR_DELEGATION
	(<xref target="OP_GET_DIR_DELEGATION" />) operation to allow the		(<xref target="OP_GET_DIR_DELEGATION" format="default"/>) operation to a llow the
	client to ask for a		client to ask for a
	directory delegation. The delegation covers directory attributes and		directory delegation. The delegation covers directory attributes and
	all entries in the directory. If either of these change, the		all entries in the directory. If either of these change, the
	delegation will be recalled synchronously. The operation causing the		delegation will be recalled synchronously. The operation causing the
	recall will have to wait before the recall is complete. Any changes		recall will have to wait before the recall is complete. Any changes
	to directory entry attributes will not cause the delegation to be		to directory entry attributes will not cause the delegation to be
	recalled.		recalled.
	</t>		</t>
	<t>		<t>
	In addition to asking for delegations, a client can also ask for		In addition to asking for delegations, a client can also ask for
	notifications for certain events. These events include changes to		notifications for certain events. These events include changes to
	the directory's attributes and/or its contents. If a client asks for		the directory's attributes and/or its contents. If a client asks for
	notification for a certain event, the server will notify the client		notification for a certain event, the server will notify the client
	when that event occurs. This will not result in the delegation being		when that event occurs. This will not result in the delegation being
	recalled for that client. The notifications are asynchronous and		recalled for that client. The notifications are asynchronous and
	provide a way of avoiding recalls in situations where a directory is		provide a way of avoiding recalls in situations where a directory is
	changing enough that the pure recall model may not be effective while		changing enough that the pure recall model may not be effective while
	trying to allow the client to get substantial benefit. In the absence		trying to allow the client to get substantial benefit. In the absence
	of notifications, once the delegation is recalled the client has to		of notifications, once the delegation is recalled the client has to
	refresh its directory cache; this might not be very efficient for		refresh its directory cache; this might not be very efficient for
	very large directories.		very large directories.
	</t>		</t>
	<t>		<t>
	The delegation is read-only and the client may not make changes to		The delegation is read-only and the client may not make changes to
	the directory other than by performing NFSv4.1 operations that modify		the directory other than by performing NFSv4.1 operations that modify
	the directory or the associated file attributes so that the server		the directory or the associated file attributes so that the server
	has knowledge of these changes. In order to keep the client's		has knowledge of these changes. In order to keep the client's
	namespace synchronized with that of the server, the server will notify		namespace synchronized with that of the server, the server will notify
	the delegation-holding client (assuming it has requested		the delegation-holding client (assuming it has requested
	notifications) of the changes made as a result of that client's		notifications) of the changes made as a result of that client's
	directory-modifying operations. This is to avoid any need for		directory-modifying operations. This is to avoid any need for
	that client to send subsequent GETATTR or READDIR operations		that client to send subsequent GETATTR or READDIR operations
	to the server. If a single client is holding the delegation		to the server. If a single client is holding the delegation
	and that client makes any changes to the directory (i.e., the		and that client makes any changes to the directory (i.e., the
	changes are made via operations sent on a session		changes are made via operations sent on a session
	associated with the client ID holding the delegation), the		associated with the client ID holding the delegation), the
	delegation will not be recalled. Multiple clients may hold a delegation		delegation will not be recalled. Multiple clients may hold a delegation
	on the same directory, but if any such client modifies the directory,		on the same directory, but if any such client modifies the directory,
	the server MUST recall the delegation from the other clients,		the server <bcp14>MUST</bcp14> recall the delegation from the other clie nts,
	unless those clients have made provisions to be notified of that		unless those clients have made provisions to be notified of that
	sort of modification.		sort of modification.
	</t>		</t>
	<t>		<t>
	Delegations can be recalled by the server at any time. Normally, the		Delegations can be recalled by the server at any time. Normally, the
	server will recall the delegation when the directory changes in a way		server will recall the delegation when the directory changes in a way
	that is not covered by the notification, or when the directory		that is not covered by the notification, or when the directory
	changes and notifications have not been requested.		changes and notifications have not been requested.
	If another client removes the directory for		If another client removes the directory for
	which a delegation has been granted, the server will recall the		which a delegation has been granted, the server will recall the
	delegation.		delegation.
	</t>		</t>
	</section>		</section>
	<section title="Attributes in Support of Directory Notifications">		<section numbered="true" toc="default">
	<t>		<name>Attributes in Support of Directory Notifications</name>
	See <xref target="dir_not_attrs" /> for a description of the attributes		<t>
			See <xref target="dir_not_attrs" format="default"/> for a description of
			the attributes
	associated with directory notifications.		associated with directory notifications.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="Directory Delegation Recall">		<name>Directory Delegation Recall</name>
	<t>		<t>
	The server will recall the directory delegation by sending a callback		The server will recall the directory delegation by sending a callback
	to the client. It will use the same callback procedure as used for		to the client. It will use the same callback procedure as used for
	recalling file delegations. The server will recall the delegation		recalling file delegations. The server will recall the delegation
	when the directory changes in a way that is not covered by the		when the directory changes in a way that is not covered by the
	notification. However, the server need not recall the delegation if		notification. However, the server need not recall the delegation if
	attributes of an entry within the directory change.		attributes of an entry within the directory change.
	</t>		</t>
	<t>		<t>
	If the		If the
	server notices that handing out a delegation for a directory is		server notices that handing out a delegation for a directory is
	causing too many notifications to be sent out, it may decide to		causing too many notifications to be sent out, it may decide to
	not hand out delegations for that directory and/or recall those already		not hand out delegations for that directory and/or recall those already
	granted. If a client tries to remove the directory for which		granted. If a client tries to remove the directory for which
	a delegation has been granted, the server will recall all associated del egations.		a delegation has been granted, the server will recall all associated del egations.
	</t>		</t>
	<t>		<t>
	The implementation sections for a number		The implementation sections for a number
	of operations describe situations in which notification or		of operations describe situations in which notification or
	delegation recall would be required under some common circumstances.		delegation recall would be required under some common circumstances.
	In this regard, a similar set of caveats to those listed		In this regard, a similar set of caveats to those listed
	in <xref target="deleg_and_cb" /> apply.		in <xref target="deleg_and_cb" format="default"/> apply.
	<list style="symbols">
	<t>
	For CREATE, see <xref target="OP_CREATE_IMPLEMENTATION" />.
	</t>
	<t>
	For LINK, see <xref target="OP_LINK_IMPLEMENTATION" />.
	</t>
	<t>
	For OPEN, see <xref target="OP_OPEN_IMPLEMENTATION" />.
	</t>
	<t>
	For REMOVE, see <xref target="OP_REMOVE_IMPLEMENTATION" />.
	</t>
	<t>
	For RENAME, see <xref target="OP_RENAME_IMPLEMENTATION" />.
	</t>		</t>
			<ul spacing="normal">
			<li>
			For CREATE, see <xref target="OP_CREATE_IMPLEMENTATION" format="defa
			ult"/>.
			</li>
			<li>
			For LINK, see <xref target="OP_LINK_IMPLEMENTATION" format="default"
			/>.
			</li>
			<li>
			For OPEN, see <xref target="OP_OPEN_IMPLEMENTATION" format="default"
			/>.
			</li>
			<li>
			For REMOVE, see <xref target="OP_REMOVE_IMPLEMENTATION" format="defa
			ult"/>.
			</li>
			<li>
			For RENAME, see <xref target="OP_RENAME_IMPLEMENTATION" format="defa
			ult"/>.
			</li>
			<li>
			For SETATTR, see <xref target="OP_SETATTR_IMPLEMENTATION" format="de
			fault"/>.
			</li>
			</ul>
			</section>
			<section numbered="true" toc="default">
			<name>Directory Delegation Recovery</name>
	<t>		<t>
	For SETATTR, see <xref target="OP_SETATTR_IMPLEMENTATION" />.
	</t>
	</list>
	</t>
	</section>
	<section title="Directory Delegation Recovery">
	<t>
	Recovery from client or server restart for state on regular files		Recovery from client or server restart for state on regular files
	has two main goals: avoiding the necessity of		has two main goals: avoiding the necessity of
	breaking application guarantees with respect to locked files and		breaking application guarantees with respect to locked files and
	delivery of updates cached at the client. Neither of these		delivery of updates cached at the client. Neither of these
	goals applies to directories protected by OPEN_DELEGATE_READ delegations and		goals applies to directories protected by OPEN_DELEGATE_READ delegations and
	notifications. Thus, no provision is made for reclaiming		notifications. Thus, no provision is made for reclaiming
	directory delegations in the event of client or server restart.		directory delegations in the event of client or server restart.
	The client can simply establish a directory delegation in the		The client can simply establish a directory delegation in the
	same fashion as was done initially.		same fashion as was done initially.
	</t>		</t>
			</section>
			</section>
	</section>		</section>
			<section anchor="NEW11" numbered="true" toc="default">
	</section>		<name>Multi-Server Namespace</name>
	</section>		<t>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->
	<!-- Copyright (C) The IETF Trust (2007-2008) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="NEW11"
	title="Multi-Server Namespace">
	<t>
	NFSv4.1 supports attributes that allow a namespace to extend		NFSv4.1 supports attributes that allow a namespace to extend
	beyond the boundaries of a single server. It is desirable		beyond the boundaries of a single server. It is desirable
	that clients and servers support construction of such		that clients and servers support construction of such
	multi-server namespaces. Use of such multi-server namespaces		multi-server namespaces. Use of such multi-server namespaces
	is OPTIONAL however, and for many purposes,		is <bcp14>OPTIONAL</bcp14>; however, and for many purposes,
	single-server namespaces are perfectly acceptable. Use of		single-server namespaces are perfectly acceptable. The use
	multi-server namespaces can provide many advantages, by		of multi-server namespaces can provide many advantages
	separating a file system's logical position in a namespace from		by separating a file system's logical position in a namespace
	the (possibly changing) logistical and administrative		from the (possibly changing) logistical and administrative
	considerations that result in particular file systems being		considerations that cause a particular file system to be
	located on particular servers via a single network access paths known		located on a particular server via a single network access
	in advance or determined using DNS.		path that has to be known in advance or determined using DNS.
	</t>		</t>
	<section title="Terminology"		<section anchor="SEC11-TERM" numbered="true" toc="default">
	anchor="SEC11-TERM">		<name>Terminology</name>
	<t>		<t>
	In this section as a whole (i.e. within all of <xref target="NEW11"/>),		In this section as a whole (i.e., within all of <xref target="NEW11" forma
			t="default"/>),
	the phrase "client ID" always refers to the		the phrase "client ID" always refers to the
	64-bit shorthand identifier assigned by the server (a clientid4)		64-bit shorthand identifier assigned by the server (a clientid4)
	and never to the structure which the client uses to identify itself		and never to the structure that the client uses to identify itself
	to the server (called an nfs_client_id4 or client_owner in NFSv4.0		to the server (called an nfs_client_id4 or client_owner in NFSv4.0
	and NFSv4.1 respectively). The opaque identifier within those		and NFSv4.1, respectively). The opaque identifier within those
	structures is referred to as a "client id string".		structures is referred to as a "client id string".
	</t>		</t>
			<section anchor="SEC11-TERM-trunking" numbered="true" toc="default">
	<section title="Terminology Related to Trunking"		<name>Terminology Related to Trunking</name>
	anchor="SEC11-TERM-trunking">		<t>
	<t>
	It is particularly important to clarify the distinction		It is particularly important to clarify the distinction
	between trunking detection and		between trunking detection and trunking discovery.
	trunking discovery. The definitions we present are		The definitions we present are applicable to all
	applicable to all
	minor versions of NFSv4, but we will focus on how		minor versions of NFSv4, but we will focus on how
	these		these terms apply to NFS version 4.1.
	terms apply to NFS version 4.1.		</t>
	<list style ='symbols'>		<ul spacing="normal">
	<t>		<li>
			<t>
	Trunking detection refers to ways of deciding whether two		Trunking detection refers to ways of deciding whether two
	specific network		specific network
	addresses are connected to the same NFSv4 server. The		addresses are connected to the same NFSv4 server. The
	means available to make this determination depends on the protocol		means available to make this determination depends on the protocol
	version, and, in some cases, on the client implementation.		version, and, in some cases, on the client implementation.
	<vspace blankLines="1"/>		</t>
			<t>
	In the case of NFS version 4.1 and later minor versions, the		In the case of NFS version 4.1 and later minor versions, the
	means of		means of
	trunking detection are as described in this document		trunking detection are as described in this document
	and are available		and are available to every client. Two network addresses
	to every client. Two network addresses
	connected to the same server can always be used together		connected to the same server can always be used together
	to access a particular server		to access a particular server
	but cannot necessarily be used together		but cannot necessarily be used together
	to access a single session. See below for definitions		to access a single session. See below for definitions
	of the terms "server-trunkable" and "session-trunkable"		of the terms "server-trunkable" and "session-trunkable".
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	Trunking discovery is a process by which a client using one		Trunking discovery is a process by which a client using one
	network address can obtain other addresses that are connected		network address can obtain other addresses that are connected
	to the		to the same server.
	same server.
	Typically, it builds on a trunking detection facility by providing		Typically, it builds on a trunking detection facility by providing
	one or more methods by which candidate addresses are made		one or more methods by which candidate addresses are made
	available to the client		available to the client,
	who can then use trunking detection to appropriately filter them.		who can then use trunking detection to appropriately filter them.
	<vspace blankLines="1"/>		</t>
	Despite the support for trunking detection there was no		<t>
			Despite the support for trunking detection, there was no
	description of trunking discovery provided in		description of trunking discovery provided in
	RFC5661 <xref target="RFC5661"/>, making it necessary to provide		RFC 5661 <xref target="RFC5661" format="default"/>, making it necessary to provide
	those means in this document.		those means in this document.
	</t>		</t>
	</list>		</li>
	</t>		</ul>
	<t>		<t>
	The combination of a server network address and a particular		The combination of a server network address and a particular
	connection type to be used by a connection		connection type to be used by a connection
	is referred to as a "server endpoint". Although using different		is referred to as a "server endpoint". Although using different
	connection types may result in different ports being used, the		connection types may result in different ports being used, the
	use of different ports by multiple connections to the same		use of different ports by multiple connections to the same
	network address in such cases is not the essence of the distinction		network address in such cases is not the essence of the distinction
	between the two endpoints used. This is in contrast to the case		between the two endpoints used. This is in contrast to the case
	of port-specific endpoints,		of port-specific endpoints,
	in which the explicit specification of port numbers within network		in which the explicit specification of port numbers within network
	addresses is used to allow a single server node to support multiple		addresses is used to allow a single server node to support multiple
	NFS servers.		NFS servers.
	</t>		</t>
			<t>
	<t>
	Two network addresses connected to the same server are said to		Two network addresses connected to the same server are said to
	be server-trunkable. Two such addresses support the use of		be server-trunkable. Two such addresses support the use of
	clientid ID trunking, as described in <xref target="Trunking"/>.		client ID trunking, as described in <xref target="Trunking" format="defau
	</t>		lt"/>.
	<t>		</t>
			<t>
	Two network addresses connected to the same server such that		Two network addresses connected to the same server such that
	those addresses can be used to support a single common session		those addresses can be used to support a single common session
	are referred to as session-trunkable. Note that two addresses		are referred to as session-trunkable. Note that two addresses
	may be server-trunkable without being session-trunkable and that		may be server-trunkable without being session-trunkable, and that,
	when two connections of different connection types are made		when two connections of different connection types are made
	to the same network address and are based on a single file		to the same network address and are based on a single file
	system location entry		system location entry, they are always
	they are always
	session-trunkable, independent of the connection type, as		session-trunkable, independent of the connection type, as
	specified by <xref target="Trunking"/>, since their derivation from		specified by <xref target="Trunking" format="default"/>, since their deri
	the same file system location entry together with the identity of		vation from
	their network addresses assures that both		the same file system location entry, together with the identity of
	connections are to the		their network addresses, assures that both connections are to the
	same server and will return server-owner information allowing		same server and will return server-owner information, allowing
	session trunking to be used.		session trunking to be used.
	</t>		</t>
	</section>		</section>
	<section title="Terminology Related to File System Location"		<section anchor="SEC11-TERM-loc" numbered="true" toc="default">
	anchor="SEC11-TERM-loc">		<name>Terminology Related to File System Location</name>
	<t>		<t>
	Regarding terminology relating to the construction of multi-server		Regarding the terminology that relates to the construction of multi-server
	namespaces out of a set of local per-server namespaces:		namespaces out of a set of local per-server namespaces:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
	Each server has a set of exported file systems which may be accessed		<li>
			Each server has a set of exported file systems that may be accessed
	by NFSv4 clients. Typically, this is done by assigning each		by NFSv4 clients. Typically, this is done by assigning each
	file system a name within the pseudo-fs associated with the		file system a name within the pseudo-fs associated with the
	server, although the pseudo-fs may be dispensed with if there		server, although the pseudo-fs may be dispensed with if there
	is only a single exported file system. Each such file system		is only a single exported file system. Each such file system
	is part of the server's local namespace, and can be considered		is part of the server's local namespace, and can be considered
	as a file system instance within a larger multi-server		as a file system instance within a larger multi-server namespace.
	namespace.		</li>
	</t>		<li>
	<t>
	The set of all exported file systems for a given server		The set of all exported file systems for a given server
	constitutes that server's local namespace.		constitutes that server's local namespace.
	</t>		</li>
	<t>		<li>
	In some cases, a server will have a namespace more extensive		In some cases, a server will have a namespace more extensive
	than its local namespace by using features associated with		than its local namespace by using features associated with
	attributes that provide file system location information.		attributes that provide file system location information.
	These features,		These features,
	which allow construction of a multi-server namespace,		which allow construction of a multi-server namespace,
	are all described in individual sections below and include		are all described in individual sections below and include
	referrals (described in <xref target="SEC11-USES-ref"/>),		referrals (<xref target="SEC11-USES-ref" format="default"/>),
	migration (described in <xref target="SEC11-USES-migr"/>), and		migration (<xref target="SEC11-USES-migr" format="default"/>), and
	replication (described in <xref target="SEC11-USES-repl"/>).		replication (<xref target="SEC11-USES-repl" format="default"/>).
	</t>		</li>
	<t>		<li>
	A file system present in a server's pseudo-fs may have multiple		A file system present in a server's pseudo-fs may have multiple
	file system instances on different servers associated with it.		file system instances on different servers associated with it.
	All such instances are considered replicas of one another.		All such instances are considered replicas of one another.
	Whether such replicas can be used simultaneously is discussed in		Whether such replicas can be used simultaneously is discussed in
	<xref target="SEC11-EFF-simul"/>, while the level of		<xref target="SEC11-EFF-simul" format="default"/>, while the level of
	co-ordination between them (important when switching		coordination between them (important when switching
	between them) is discussed in Sections		between them) is discussed in Sections
	<xref target="SEC11-EFF-fh" format="counter"/>		<xref target="SEC11-EFF-fh" format="counter"/>
	through <xref target="SEC11-EFF-data" format="counter"/>		through <xref target="SEC11-EFF-data" format="counter"/> below.
	below.		</li>
			<li>
	</t>
	<t>
	When a file system is present in a server's pseudo-fs, but		When a file system is present in a server's pseudo-fs, but
	there is no corresponding local file system, it is said to		there is no corresponding local file system, it is said to
	be "absent". In such cases, all associated instances will		be "absent". In such cases, all associated instances will
	be accessed on other servers.		be accessed on other servers.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		Regarding the terminology that relates to attributes used in trunking
	Regarding terminology relating to attributes used in trunking
	discovery and other multi-server namespace features:		discovery and other multi-server namespace features:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	File system location attributes include the fs_locations and		File system location attributes include the fs_locations and
	fs_locations_info attributes.		fs_locations_info attributes.
	</t>		</li>
	<t>		<li>
	File system location entries provide the individual		<t>
	file system locations		File system location entries provide the individual file system
	within the file system location attributes.		locations within the file system location attributes.
	Each such entry specifies a		Each such entry specifies a
	server, in the form of a host name or an address, and an fs name,		server, in the form of a hostname or an address, and an fs name,
	which designates the location of the file system within		which designates the location of the file system within
	the server's local namespace. A file system		the server's local namespace. A file system location entry designates a
	location entry designates a set		set
	of server endpoints to which the client may establish connections.		of server endpoints to which the client may establish connections.
	There may be multiple endpoints because a host name may map to		There may be multiple endpoints because a hostname may map to
	multiple network addresses and because multiple connection types		multiple network addresses and because multiple connection types
	may be		may be
	used to communicate with a single network address. However,		used to communicate with a single network address. However,
	except where an explicit port numbers are used to designate a set		except where explicit port numbers are used to designate a set
	of server within a single server node, all		of servers within a single server node, all
	such endpoints MUST designate a way of connecting to a single server.		such endpoints <bcp14>MUST</bcp14> designate a way of connecting to a sin
			gle server.
	The exact form of the location entry varies with the		The exact form of the location entry varies with the
	particular file system location attribute used, as described in		particular file system location attribute used, as described in
	<xref target="SEC11-loc-attr"/>.		<xref target="SEC11-loc-attr" format="default"/>.
	<vspace blankLines='1'/>		</t>
			<t>
	The network addresses used in file system location entries		The network addresses used in file system location entries
	typically appear without port number indications and are		typically appear without port number indications and are
	used to designate a server at one of the standard ports for NFS access,		used to designate a server at one of the standard ports for NFS access,
	e.g., 2049 for TCP, or 20049 for use with RPC-over-RDMA. Port		e.g., 2049 for TCP or 20049 for use with RPC-over-RDMA. Port
	numbers may be used		numbers may be used
	in file system location entries to designate servers (typically		in file system location entries to designate servers (typically
	user-level ones) accessed using other port numbers. In the case where		user-level ones) accessed using other port numbers. In the case where
	network addresses indicate trunking relationships, use of an explicit		network addresses indicate trunking relationships, the use of an explicit
	port number is inappropriate since trunking is a relationship between		port number is inappropriate since trunking is a relationship between
	network addresses. See <xref target="SEC11-USES-trunk"/> for		network addresses. See <xref target="SEC11-USES-trunk" format="default"/ > for
	details.		details.
	</t>		</t>
	<t>		</li>
			<li>
	File system location elements are derived from		File system location elements are derived from
	location entries and each		location entries, and each
	describes a particular network access path, consisting of a network		describes a particular network access path consisting of a network
	address and a location within the server's local namespace.		address and a location within the server's local namespace.
	Such location elements need not appear		Such location elements need not appear
	within a file system location attribute, but the		within a file system location attribute, but the
	existence of each location element derives from a corresponding		existence of each location element derives from a corresponding
	location entry. When a		location entry. When a
	location entry specifies an IP address there is only a single		location entry specifies an IP address, there is only a single
	corresponding location element. File system location entries that		corresponding location element. File system location entries that
	contain a host name are resolved using DNS, and may result		contain a hostname are resolved using DNS, and may result
	in one or more location elements. All location elements		in one or more location elements. All location elements
	consist of a location address which includes the IP address of		consist of a location address that includes the IP address of
	an interface to a server and an fs name which is the location		an interface to a server and an fs name, which is the location
	of the file system within the server's local namespace. The fs name		of the file system within the server's local namespace. The fs name
	can be empty if the server has no pseudo-fs and only a single exported		can be empty if the server has no pseudo-fs and only a single exported
	file system at the root filehandle.		file system at the root filehandle.
	</t>		</li>
	<t>		<li>
	Two file system location elements are said to be		Two file system location elements are said to be
	server-trunkable if they		server-trunkable if they
	specify the same fs name and the location addresses are such		specify the same fs name and the location addresses are such
	that the location addresses are server-trunkable. When the		that the location addresses are server-trunkable. When the
	corresponding network paths are used, the client will always be		corresponding network paths are used, the client will always be
	able to use client ID trunking, but will only be able to use		able to use client ID trunking, but will only be able to use
	session trunking if the paths are also session-trunkable.		session trunking if the paths are also session-trunkable.
			</li>
	</t>		<li>
	<t>
	Two file system location elements are said to be session-trunkable		Two file system location elements are said to be session-trunkable
	if they		if they
	specify the same fs name and the location addresses are such		specify the same fs name and the location addresses are such
	that the location addresses are session-trunkable. When the		that the location addresses are session-trunkable. When the
	corresponding network paths are used, the client will be able to		corresponding network paths are used, the client will be able to
	able to use either client ID trunking or session trunking.		able to use either client ID trunking or session trunking.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Discussion of the term "replica" is complicated by the fact that		Discussion of the term "replica" is complicated by the fact that
	the term was used in RFC5661 <xref target="RFC5661"/>, with a meaning		the term was used in RFC 5661 <xref target="RFC5661" format="default"/> wi
	different from that in this document. In short,		th a meaning
	in <xref target="RFC5661"/> each replica is identified by a		different from that used in this document. In short,
	single network access path while, in the current document a set		in <xref target="RFC5661" format="default"/> each replica is identified by
	of network access paths which have server-trunkable network		a
			single network access path, while in the current document, a set
			of network access paths that have server-trunkable network
	addresses and the same root-relative file system pathname is		addresses and the same root-relative file system pathname is
	considered to be a single replica with multiple network access		considered to be a single replica with multiple network access
	paths.		paths.
	</t>		</t>
	<t>		<t>
	Each set of server-trunkable location elements defines a set of		Each set of server-trunkable location elements defines a set of
	available network access paths to a particular file system.		available network access paths to a particular file system.
	When there		When there
	are multiple such file systems, each of which contains the		are multiple such file systems, each of which containing the
	same data, these file systems are considered replicas		same data, these file systems are considered replicas
	of one another. Logically, such replication		of one another. Logically, such replication
	is symmetric, since the fs currently in use and an alternate fs		is symmetric, since the fs currently in use and an alternate fs
	are replicas of each other. Often, in other documents, the term		are replicas of each other. Often, in other documents, the term
	"replica" is not applied to the fs currently in use, despite the		"replica" is not applied to the fs currently in use, despite the
	fact that the replication relation is inherently symmetric.		fact that the replication relation is inherently symmetric.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section title="File System Location Attributes"		<section anchor="SEC11-loc-attr" numbered="true" toc="default">
	anchor="SEC11-loc-attr">		<name>File System Location Attributes</name>
	<t>		<t>
	NFSv4.1 contains attributes that provide information		NFSv4.1 contains attributes that provide information
	about how (i.e., at what network address and namespace position)		about how a given file system may be accessed
	a given file system may be accessed. As a result, file systems		(i.e., at what network address and namespace position). As a result, file
			systems
	in the namespace of one server can be		in the namespace of one server can be
	associated with one or more instances of that		associated with one or more instances of that
	file system on other servers. These attributes contain file		file system on other servers. These attributes contain file
	system location		system location
	entries specifying a server address		entries specifying a server address
	target (either as a DNS name representing one or more IP		target (either as a DNS name representing one or more IP
	addresses or as a specific IP address) together with the pathname		addresses or as a specific IP address) together with the pathname
	of that file system within the associated single-server namespace.		of that file system within the associated single-server namespace.
	</t>		</t>
	<t>		<t>
	The fs_locations_info RECOMMENDED attribute		The fs_locations_info <bcp14>RECOMMENDED</bcp14> attribute
	allows specification of one or more file system instance locations		allows specification of one or more file system instance locations
	where the data corresponding to a given file		where the data corresponding to a given file
	system may be found. This attribute provides to the client,		system may be found.
	in addition to specification of file system instance locations,		In addition to the specification of file system instance locations,
	other helpful		this attribute provides helpful information to do the following:
	information such as:		</t>
	<list style='symbols'>		<ul spacing="normal">
	<t>		<li>
	Information guiding choices among the various file system instances		Guide choices among the various file system instances
	provided (e.g., priority for use, writability, currency, etc.).		provided (e.g., priority for use, writability, currency, etc.).
	</t>		</li>
	<t>		<li>
			Help the client efficiently effect as seamless
	Information to help the client efficiently effect as seamless		a transition as possible among multiple file system instances,
	a transition		when and if that should be necessary.
	as possible among multiple file system instances, when and if		</li>
	that should be necessary.		<li>
	</t>		Guide the selection of the appropriate
	<t>
	Information helping to guide the selection of the appropriate
	connection type to be used when establishing a connection.		connection type to be used when establishing a connection.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Within the fs_locations_info attribute, each		Within the fs_locations_info attribute, each
	fs_locations_server4 entry corresponds to a file system		fs_locations_server4 entry corresponds to a file system
	location entry with the		location entry: the fls_server field designates the server,
	fls_server field designating the server, with the location pathname		and the fl_rootpath field of the encompassing fs_locations_item4
	within		gives the location pathname within the server's pseudo-fs.
	the server's pseudo-fs given by the fl_rootpath field of the		</t>
	encompassing fs_locations_item4.		<t>
	</t>
	<t>
	The fs_locations attribute defined in NFSv4.0 is also a part of		The fs_locations attribute defined in NFSv4.0 is also a part of
	NFSv4.1. This attribute		NFSv4.1. This attribute only allows specification of the file system
	only allows specification
	of the file system
	locations where the data corresponding to a given file		locations where the data corresponding to a given file
	system may be found. Servers SHOULD make this attribute available		system may be found. Servers <bcp14>SHOULD</bcp14> make this attribute a vailable
	whenever fs_locations_info is supported, but client use of		whenever fs_locations_info is supported, but client use of
	fs_locations_info is preferable, as it provides more information.		fs_locations_info is preferable because it provides more information.
	</t>		</t>
	<t>		<t>
	Within the fs_location attribute, each fs_location4 contains a		Within the fs_locations attribute, each fs_location4 contains a
	file system location entry with the server field designating		file system location entry with the server field designating
	the server and		the server and the rootpath field giving the location pathname
	the rootpath field giving the location pathname within the server's		within the server's pseudo-fs.
	pseudo-fs.		</t>
	</t>		</section>
	</section>		<section anchor="presence_or_absence" numbered="true" toc="default">
	<section title="File System Presence or Absence"		<name>File System Presence or Absence</name>
	anchor="presence_or_absence">		<t>
	<t>
	A given location in an NFSv4.1 namespace (typically but not necessarily		A given location in an NFSv4.1 namespace (typically but not necessarily
	a multi-server namespace) can have a number of file system instance		a multi-server namespace) can have a number of file system instance
	locations		locations
	associated with it (via the fs_locations or fs_locations_info		associated with it (via the fs_locations or fs_locations_info
	attribute). There may also be an actual current file system at		attribute). There may also be an actual current file system at
	that location, accessible via normal namespace operations (e.g.,		that location, accessible via normal namespace operations (e.g.,
	LOOKUP). In this case, the file system is said to be		LOOKUP). In this case, the file system is said to be
	"present" at that position in the namespace, and clients will		"present" at that position in the namespace, and clients will
	typically use it, reserving use of additional locations		typically use it, reserving use of additional locations
	specified via the location-related attributes to situations in		specified via the location-related attributes to situations in
	which the principal location is no longer available.		which the principal location is no longer available.
	</t>		</t>
	<t>		<t>
	When there is no actual file system at the namespace location		When there is no actual file system at the namespace location
	in question, the file system is said to be "absent". An absent		in question, the file system is said to be "absent". An absent
	file system contains no files or directories other than the		file system contains no files or directories other than the
	root. Any reference to it, except		root. Any reference to it, except
	to access a small set of attributes useful in determining		to access a small set of attributes useful in determining
	alternate locations, will result in an error, NFS4ERR_MOVED.		alternate locations, will result in an error, NFS4ERR_MOVED.
	Note that if the server ever returns the error NFS4ERR_MOVED,		Note that if the server ever returns the error NFS4ERR_MOVED,
	it MUST support the fs_locations		it <bcp14>MUST</bcp14> support the fs_locations
	attribute and SHOULD support the fs_locations_info and fs_status		attribute and <bcp14>SHOULD</bcp14> support the fs_locations_info and fs_s
			tatus
	attributes.		attributes.
	</t>		</t>
	<t>		<t>
	While the error name suggests that we have a case of a file system		While the error name suggests that we have a case of a file system
	that once was present, and has only become absent later, this is		that once was present, and has only become absent later, this is
	only one possibility. A position in the namespace may be permanently		only one possibility. A position in the namespace may be permanently
	absent with the set of file system(s) designated by the location		absent with the set of file system(s) designated by the location
	attributes being the only realization.		attributes being the only realization.
	The name NFS4ERR_MOVED reflects an earlier,		The name NFS4ERR_MOVED reflects an earlier,
	more limited conception of its function, but this error will be		more limited conception of its function, but this error will be
	returned whenever the referenced file system is absent, whether it		returned whenever the referenced file system is absent, whether it
	has moved or not.		has moved or not.
	</t>		</t>
	<t>		<t>
	Except in the case of GETATTR-type operations (to be discussed		Except in the case of GETATTR-type operations (to be discussed
	later), when the		later), when the
	current filehandle at the start of an operation is within an		current filehandle at the start of an operation is within an
	absent file system, that operation is not performed and the error		absent file system, that operation is not performed and the error
	NFS4ERR_MOVED is returned, to indicate that the file system is		NFS4ERR_MOVED is returned, to indicate that the file system is
	absent on the current server.		absent on the current server.
	</t>		</t>
	<t>		<t>
	Because a GETFH cannot succeed if the current filehandle is		Because a GETFH cannot succeed if the current filehandle is
	within an absent file system, filehandles within an absent		within an absent file system, filehandles within an absent
	file system cannot be transferred to the client. When a		file system cannot be transferred to the client. When a
	client does have filehandles within an absent file system, it		client does have filehandles within an absent file system, it
	is the result of obtaining them when the file system was		is the result of obtaining them when the file system was
	present, and having the file system become		present, and having the file system become
	absent subsequently.		absent subsequently.
	</t>		</t>
	<t>		<t>
	It should be noted that because the check for the current		It should be noted that because the check for the current
	filehandle being within an absent file system happens at the		filehandle being within an absent file system happens at the
	start of every operation, operations that change the current		start of every operation, operations that change the current
	filehandle so that it is within an absent file system will not		filehandle so that it is within an absent file system will not
	result in an error. This allows such combinations as		result in an error. This allows such combinations as
	PUTFH-GETATTR and LOOKUP-GETATTR to be used to get attribute		PUTFH-GETATTR and LOOKUP-GETATTR to be used to get attribute
	information, particularly location attribute information,		information, particularly location attribute information,
	as discussed below.		as discussed below.
	</t>		</t>
	<t>		<t>
	The RECOMMENDED file system attribute fs_status		The <bcp14>RECOMMENDED</bcp14> file system attribute fs_status
	can be used to interrogate the present/absent status of a		can be used to interrogate the present/absent status of a
	given file system.		given file system.
	</t>		</t>
	</section>		</section>
	<section title="Getting Attributes for an Absent File System"		<section anchor="absent_fs_attributes" numbered="true" toc="default">
	anchor="absent_fs_attributes" >		<name>Getting Attributes for an Absent File System</name>
	<t>		<t>
	When a file system is absent, most attributes are not available,		When a file system is absent, most attributes are not available,
	but it is necessary to allow the client access to the small		but it is necessary to allow the client access to the small
	set of attributes that are available, and most particularly		set of attributes that are available, and most particularly
	those that give information about the correct current locations		those that give information about the correct current locations
	for this file system: fs_locations and fs_locations_info.		for this file system: fs_locations and fs_locations_info.
	</t>		</t>
	<section anchor="absent_getattr"		<section anchor="absent_getattr" numbered="true" toc="default">
	title="GETATTR within an Absent File System">		<name>GETATTR within an Absent File System</name>
	<t>		<t>
	As mentioned above, an exception is made for GETATTR in that		As mentioned above, an exception is made for GETATTR in that
	attributes may be obtained for a filehandle within an absent		attributes may be obtained for a filehandle within an absent
	file system. This exception only applies if the attribute		file system. This exception only applies if the attribute
	mask contains at least one attribute bit that indicates the		mask contains at least one attribute bit that indicates the
	client is interested in a result regarding an absent file		client is interested in a result regarding an absent file
	system: fs_locations, fs_locations_info, or fs_status.		system: fs_locations, fs_locations_info, or fs_status.
	If none of these attributes		If none of these attributes
	is requested, GETATTR will result in an NFS4ERR_MOVED error.		is requested, GETATTR will result in an NFS4ERR_MOVED error.
	</t>		</t>
	<t>		<t>
	When a GETATTR is done on an absent file system, the set of		When a GETATTR is done on an absent file system, the set of
	supported attributes is very limited. Many attributes, including		supported attributes is very limited. Many attributes, including
	those that are normally REQUIRED, will not be available on an		those that are normally <bcp14>REQUIRED</bcp14>, will not be available o n an
	absent file system. In addition to the attributes mentioned		absent file system. In addition to the attributes mentioned
	above (fs_locations, fs_locations_info, fs_status), the following		above (fs_locations, fs_locations_info, fs_status), the following
	attributes SHOULD be available on absent file systems. In the		attributes <bcp14>SHOULD</bcp14> be available on absent file systems. I
	case of RECOMMENDED attributes, they should be available at		n the
			case of <bcp14>RECOMMENDED</bcp14> attributes, they should be available
			at
	least to the same degree that they are available on present file systems .		least to the same degree that they are available on present file systems .
	</t>		</t>
	<t>		<dl newline="false" spacing="normal">
	<list style='hanging'>		<dt>change_policy:</dt>
	<t hangText="change_policy:">		<dd>
	This attribute is useful for absent file systems		This attribute is useful for absent file systems
	and can be helpful in summarizing to the client when any		and can be helpful in summarizing to the client when any
	of the location-related attributes change.		of the location-related attributes change.
	</t>		</dd>
	<t hangText="fsid:">		<dt>fsid:</dt>
			<dd>
	This attribute should be provided so that the client		This attribute should be provided so that the client
	can determine file system boundaries, including, in		can determine file system boundaries, including, in
	particular, the boundary between present and absent file		particular, the boundary between present and absent file
	systems. This value must be different from any other fsid		systems. This value must be different from any other fsid
	on the current server and need have no particular relationship		on the current server and need have no particular relationship
	to fsids on any particular destination to which the client		to fsids on any particular destination to which the client
	might be directed.		might be directed.
	</t>		</dd>
	<t hangText="mounted_on_fileid:">		<dt>mounted_on_fileid:</dt>
			<dd>
	For objects at the top of an absent		For objects at the top of an absent
	file system, this attribute needs to be available. Since		file system, this attribute needs to be available. Since
	the fileid is within the present parent file		the fileid is within the present parent file
	system, there should be no need to reference the absent file		system, there should be no need to reference the absent file
	system to provide this information.		system to provide this information.
	</t>		</dd>
	</list>		</dl>
	</t>		<t>
	<t>		Other attributes <bcp14>SHOULD NOT</bcp14> be made available for absent
	Other attributes SHOULD NOT be made available for absent file		file
	systems, even when it is possible to provide them. The server		systems, even when it is possible to provide them. The server
	should not assume that more information is always better and		should not assume that more information is always better and
	should avoid gratuitously providing additional information.		should avoid gratuitously providing additional information.
	</t>		</t>
	<t>		<t>
	When a GETATTR operation includes a bit mask for one of the		When a GETATTR operation includes a bit mask for one of the
	attributes fs_locations, fs_locations_info, or fs_status, but		attributes fs_locations, fs_locations_info, or fs_status, but
	where the bit mask includes attributes that are not supported,		where the bit mask includes attributes that are not supported,
	GETATTR will not return an error, but will return the mask		GETATTR will not return an error, but will return the mask
	of the actual attributes supported with the results.		of the actual attributes supported with the results.
	</t>		</t>
	<t>		<t>
	Handling of VERIFY/NVERIFY is similar to GETATTR in that if		Handling of VERIFY/NVERIFY is similar to GETATTR in that if
	the attribute mask does not include fs_locations, fs_locations_info,		the attribute mask does not include fs_locations, fs_locations_info,
	or fs_status, the error NFS4ERR_MOVED will result. It differs in		or fs_status, the error NFS4ERR_MOVED will result. It differs in
	that any appearance in the attribute mask of an attribute not		that any appearance in the attribute mask of an attribute not
	supported for an absent file system (and note that this will		supported for an absent file system (and note that this will
	include some normally REQUIRED attributes) will also cause		include some normally <bcp14>REQUIRED</bcp14> attributes) will also caus e
	an NFS4ERR_MOVED result.		an NFS4ERR_MOVED result.
	</t>		</t>
	</section>		</section>
	<section anchor="absent_readdir"		<section anchor="absent_readdir" numbered="true" toc="default">
	title="READDIR and Absent File Systems">		<name>READDIR and Absent File Systems</name>
	<t>		<t>
	A READDIR performed when the current filehandle is within an		A READDIR performed when the current filehandle is within an
	absent file system will result in an NFS4ERR_MOVED error,		absent file system will result in an NFS4ERR_MOVED error,
	since, unlike the case of GETATTR, no such exception is		since, unlike the case of GETATTR, no such exception is
	made for READDIR.		made for READDIR.
	</t>		</t>
	<t>		<t>
	Attributes for an absent file system may be fetched via a		Attributes for an absent file system may be fetched via a
	READDIR for a directory in a present file system, when that		READDIR for a directory in a present file system, when that
	directory contains the root directories of one or more absent		directory contains the root directories of one or more absent
	file systems. In this case, the handling is as follows:		file systems. In this case, the handling is as follows:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	If the attribute set requested includes one of the attributes		If the attribute set requested includes one of the attributes
	fs_locations, fs_locations_info, or fs_status, then fetching of		fs_locations, fs_locations_info, or fs_status, then fetching of
	attributes proceeds normally and no NFS4ERR_MOVED indication		attributes proceeds normally and no NFS4ERR_MOVED indication
	is returned, even when the rdattr_error attribute is		is returned, even when the rdattr_error attribute is
	requested.		requested.
	</t>		</li>
	<t>		<li>
	If the attribute set requested does not include one of the		If the attribute set requested does not include one of the
	attributes		attributes
	fs_locations, fs_locations_info, or fs_status, then if the		fs_locations, fs_locations_info, or fs_status, then if the
	rdattr_error attribute is requested, each directory entry for		rdattr_error attribute is requested, each directory entry for
	the root of an absent file system will report		the root of an absent file system will report
	NFS4ERR_MOVED as the value of the rdattr_error attribute.		NFS4ERR_MOVED as the value of the rdattr_error attribute.
	</t>		</li>
	<t>		<li>
	If the attribute set requested does not include any of the		If the attribute set requested does not include any of the
	attributes fs_locations, fs_locations_info, fs_status, or		attributes fs_locations, fs_locations_info, fs_status, or
	rdattr_error, then the occurrence of the root of an absent		rdattr_error, then the occurrence of the root of an absent
	file system within the directory will result in the		file system within the directory will result in the
	READDIR failing with an NFS4ERR_MOVED error.		READDIR failing with an NFS4ERR_MOVED error.
	</t>		</li>
	<t>		<li>
	The unavailability of an attribute because of a file system's		The unavailability of an attribute because of a file system's
	absence, even one that is ordinarily REQUIRED, does not result		absence, even one that is ordinarily <bcp14>REQUIRED</bcp14>, does not result
	in any error indication. The set of attributes returned for		in any error indication. The set of attributes returned for
	the root directory of the absent file system in that case is		the root directory of the absent file system in that case is
	simply restricted to those actually available.		simply restricted to those actually available.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="SEC11-USES" numbered="true" toc="default">
	<section title="Uses of File System Location Information"		<name>Uses of File System Location Information</name>
	anchor="SEC11-USES">		<t>
	<t>
	The file system location attributes		The file system location attributes
	(i.e. fs_locations and fs_locations_info),		(i.e., fs_locations and fs_locations_info),
	together with the possibility of absent file systems, provide		together with the possibility of absent file systems, provide
	a number of important facilities in providing reliable, manageable,		a number of important facilities for reliable, manageable,
	and scalable data access.		and scalable data access.
	</t>		</t>
	<t>		<t>
	When a file system is present, these attributes can provide		When a file system is present, these attributes can provide
	<list style="symbols">		the following:
	<t>		</t>
	The locations of alternative replicas, to be used to access the		<ul spacing="normal">
	same data in the event of server failures,		<li>
	communications problems,		The locations of alternative replicas to be used to access the
			same data in the event of server failures, communications problems,
	or other difficulties that make continued access to the current		or other difficulties that make continued access to the current
	replica impossible or otherwise impractical. Provision and		replica impossible or otherwise impractical. Provisioning and
	use of		use of such alternate replicas is referred to as "replication"
	such alternate replicas is referred to as "replication"
	and is discussed in		and is discussed in
	<xref target="SEC11-USES-repl"/> below.		<xref target="SEC11-USES-repl" format="default"/> below.
	</t>		</li>
	<t>		<li>
	The network address(es) to be used to access the current file		The network address(es) to be used to access the current file
	system instance or replicas of it.		system instance or replicas of it. Client use of this information is
	Client use of this information is		discussed in <xref target="SEC11-USES-trunk" format="default"/> below.
	discussed in		</li>
	<xref target="SEC11-USES-trunk"/> below.		</ul>
	</t>		<t>
	</list>
	</t>
	<t>
	Under some circumstances, multiple replicas		Under some circumstances, multiple replicas
	may be used simultaneously to provide higher-performance		may be used simultaneously to provide higher-performance
	access to the file system in question, although the lack of state		access to the file system in question, although the lack of state
	sharing between servers may be an impediment to such use.		sharing between servers may be an impediment to such use.
	</t>		</t>
	<t>		<t>
	When a file system is present and becomes absent, clients can be		When a file system is present but becomes absent, clients can be
	given the opportunity to have continued access to their data,		given the opportunity to have continued access to their data
	using a different replica. In this case, a continued attempt		using a different replica. In this case, a continued attempt
	to use the data in the now-absent file system will result		to use the data in the now-absent file system will result
	in an NFS4ERR_MOVED error and, at that point, the successor		in an NFS4ERR_MOVED error, and then the successor
	replica or set of possible replica choices		replica or set of possible replica choices
	can be fetched and used to continue access. Transfer of access		can be fetched and used to continue access. Transfer of access
	to the new replica location is referred to as		to the new replica location is referred to as
	"migration", and is discussed in		"migration" and is discussed in
	<xref target="SEC11-USES-repl"/> below.		<xref target="SEC11-USES-repl" format="default"/> below.
			</t>
	</t>		<t>
	<t>		When a file system is currently absent, specification
	Where a file system is currently absent, specification
	of file system location provides a means by which file systems		of file system location provides a means by which file systems
	located on one server can be associated with a namespace		located on one server can be associated with a namespace
	defined by another server, thus allowing a general multi-server		defined by another server, thus allowing a general multi-server
	namespace facility. A designation of such a remote instance, in		namespace facility. A designation of such a remote instance, in
	place of a file system not previously present, is called		place of a file system not previously present, is called
	a "pure referral" and is discussed in		a "pure referral" and is discussed in
	<xref target="SEC11-USES-ref"/> below.		<xref target="SEC11-USES-ref" format="default"/> below.
	</t>		</t>
	<t>		<t>
	Because client support for attributes related to file		Because client support for attributes related to file
	system location is		system location is
	OPTIONAL, a server may choose to take action		<bcp14>OPTIONAL</bcp14>, a server may choose to take action
	to hide migration and referral events from such clients, by		to hide migration and referral events from such clients, by
	acting as a proxy, for example. The server can determine		acting as a proxy, for example. The server can determine
	the presence of client support from the arguments of the		the presence of client support from the arguments of the
	EXCHANGE_ID operation (see		EXCHANGE_ID operation (see
	<xref target="OP_EXCHANGE_ID_DESCRIPTION" />).		<xref target="OP_EXCHANGE_ID_DESCRIPTION" format="default"/>).
	</t>		</t>
	<section title="Combining Multiple Uses in a Single Attribute"		<section anchor="SEC11-USES-mult" numbered="true" toc="default">
	anchor="SEC11-USES-mult">		<name>Combining Multiple Uses in a Single Attribute</name>
	<t>		<t>
	A file system location attribute will sometimes contain information		A file system location attribute will sometimes contain information
	relating to the location of multiple replicas which may		relating to the location of multiple replicas, which may
	be used in different ways.		be used in different ways:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	File system location entries that relate to the file system instance		File system location entries that relate to the file system instance
	currently in		currently in
	use provide trunking information, allowing the client to		use provide trunking information, allowing the client to
	find additional network addresses by which the instance may be		find additional network addresses by which the instance may be
	accessed.		accessed.
	</t>		</li>
	<t>		<li>
	File system location entries that provide information about		File system location entries that provide information about
	replicas to which access is to		replicas to which access is to be transferred.
	be transferred.		</li>
	</t>		<li>
	<t>
	Other file system location entries that relate to replicas		Other file system location entries that relate to replicas
	that are available to		that are available to
	use in the event that access to the current replica becomes		use in the event that access to the current replica becomes
	unsatisfactory.		unsatisfactory.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		In order to simplify client handling and to allow the best choice
	In order to simplify client handling and allow the best choice
	of replicas to access, the server should adhere to the following		of replicas to access, the server should adhere to the following
	guidelines.		guidelines:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	All file system location entries that relate to a		All file system location entries that relate to a
	single file system instance		single file system instance should be adjacent.
	should be		</li>
	adjacent.		<li>
	</t>
	<t>
	File system location entries that relate to the instance		File system location entries that relate to the instance
	currently in use		currently in use should appear first.
	should appear first.		</li>
	</t>		<li>
	<t>
	File system location entries that relate to replica(s)		File system location entries that relate to replica(s)
	to which migration		to which migration
	is occurring should appear before replicas which are available		is occurring should appear before replicas that are available
	for later use if the current replica should become inaccessible.		for later use if the current replica should become inaccessible.
			</li>
	</t>		</ul>
	</list>		</section>
	</t>		<section anchor="SEC11-USES-trunk" numbered="true" toc="default">
	</section>		<name>File System Location Attributes and Trunking</name>
	<section title="File System Location Attributes and Trunking"		<t>
	anchor="SEC11-USES-trunk">
	<t>
	Trunking is the use of multiple connections between a client and		Trunking is the use of multiple connections between a client and
	server in order to increase the speed of data transfer.		server in order to increase the speed of data transfer.
	A client may determine the set of network addresses to use to		A client may determine the set of network addresses to use to
	access a given file system in a number of ways:		access a given file system in a number of ways:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	When the name of the server is known to the client, it may use		When the name of the server is known to the client, it may use
	DNS to obtain a set of network addresses to use in		DNS to obtain a set of network addresses to use in
	accessing the server.		accessing the server.
	</t>		</li>
	<t>		<li>
	The client		The client may fetch the file system location attribute for the
	may fetch the file system location attribute for the
	file system. This will		file system. This will
	provide either the name of the server (which can be turned		provide either the name of the server (which can be turned
	into a set of network addresses using DNS), or		into a set of network addresses using DNS) or
	a set of server-trunkable location entries. Using the latter		a set of server-trunkable location entries. Using the latter
	alternative, the server can		alternative, the server can
	provide addresses it regards as desirable to use		provide addresses it regards as desirable to use
	to access the file system in question. Although these entries can		to access the file system in question. Although these entries can
	contain port numbers, these port numbers are not used in determining		contain port numbers, these port numbers are not used in determining
	trunking relationships. Once the candidate addresses have been		trunking relationships. Once the candidate addresses have been
	determined and EXCHANGE_ID done to the proper server, only the value		determined and EXCHANGE_ID done to the proper server, only the value
	of the so_major field returned by the servers in question determines		of the so_major_id field returned by the servers in question determines
	whether a trunking relationship actually exists.		whether a trunking relationship actually exists.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		When the client fetches a location attribute
	It should be noted that the client, when it fetches a location		for a file system, it should be noted that the client may encounter mul
	attribute for a file system, may encounter multiple entries for		tiple entries for a number of
	a number of reasons, so that, when determining trunking information,		reasons, such that when it determines trunking information, it may
	it may have to bypass addresses not trunkable with one already		need
	known.		to bypass addresses not trunkable with one already known.
	</t>		</t>
	<t>		<t>
	The server can provide location entries that include either		The server can provide location entries that include either
	names or network addresses. It might use the latter form		names or network addresses. It might use the latter form
	because of DNS-related security concerns or because the set		because of DNS-related security concerns or because the set
	of addresses		of addresses
	to be used might require active management by the server.		to be used might require active management by the server.
	</t>		</t>
	<t>		<t>
	Location entries used to discover candidate addresses for		Location entries used to discover candidate addresses for
	use in trunking		use in trunking are subject to change, as discussed in
	are subject to change, as discussed in		<xref target="SEC11-USES-changes" format="default"/> below.
	<xref target="SEC11-USES-changes"/> below.
	The client may respond to		The client may respond to
	such changes by using additional addresses once they are		such changes by using additional addresses once they are
	verified or by ceasing to use		verified or by ceasing to use
	existing ones. The server can force the client to cease using		existing ones. The server can force the client to cease using
	an address by returning NFS4ERR_MOVED when that address is used to		an address by returning NFS4ERR_MOVED when that address is used to
	access a file system. This allows a transfer of client access		access a file system. This allows a transfer of client access
	which is similar to		that is similar to migration, although the same file system instance
	migration, although the same file system instance
	is accessed throughout.		is accessed throughout.
	</t>		</t>
	</section>		</section>
	<section title="File System Location Attributes and Connection Type Selectio		<section anchor="SEC11-USES-types" numbered="true" toc="default">
	n"		<name>File System Location Attributes and Connection Type Selection</n
	anchor="SEC11-USES-types">		ame>
			<t>
	<t>
	Because of the need to support multiple types of connections,		Because of the need to support multiple types of connections,
	clients face		clients face
	the issue of determining the proper connection type to use		the issue of determining the proper connection type to use
	when establishing		when establishing
	a connection to a given server network address. In some cases,		a connection to a given server network address. In some cases,
	this issue can be addressed through the use of the connection		this issue can be addressed through the use of the connection
	"step-up" facility described in		"step-up" facility described in
	<xref target="OP_CREATE_SESSION"/>. However,		<xref target="OP_CREATE_SESSION" format="default"/>. However,
	because there are cases is which that facility is not available,		because there are cases in which that facility is not available,
	the client may have to choose a connection type with no		the client may have to choose a connection type with no
	possibility of changing it within the scope of a single connection.		possibility of changing it within the scope of a single connection.
	</t>		</t>
	<t>		<t>
	The two file system location attributes differ as to the		The two file system location attributes differ as to the
	information made		information made available in this regard. The fs_locations attribute pro
	available in this regard. Fs_locations provides no information		vides no information
	to support connection type selection. As a result, clients		to support connection type selection. As a result, clients
	supporting multiple connection types would need to attempt to		supporting multiple connection types would need to attempt to
	establish connections using multiple connection types until		establish connections using multiple connection types until
	the one preferred		the one preferred by the client is successfully established.
	by the client is successfully established.		</t>
	</t>		<t>
	<t>		The fs_locations_info attribute includes the FSLI4TF_RDMA flag,
	Fs_locations_info includes a flag, FSLI4TF_RDMA, which, when		which is convenient for a client wishing to use RDMA. When this
	set indicates that RPC-over-RDMA support is available using		flag is set, it indicates that RPC-over-RDMA support is available
	the specified location entry, by "stepping up" an existing		using the specified location entry. A client can establish a TCP
	TCP connection to include support for RDMA operation. This flag		connection and then convert that connection to use RDMA by using
	makes it convenient for a client wishing to use RDMA. When		the step-up facility.
	this flag is set, it can		</t>
	establish a TCP connection and then convert that connection		<t>
	to use RDMA by using the step-up facility.
	</t>
	<t>
	Irrespective of the particular attribute used, when there is		Irrespective of the particular attribute used, when there is
	no indication that a step-up operation can be performed,		no indication that a step-up operation can be performed,
	a client supporting RDMA operation can establish a new RDMA		a client supporting RDMA operation can establish a new RDMA
	connection and it can be bound to		connection, and it can be bound to
	the session already established by the		the session already established by the
	TCP connection, allowing the TCP connection to be dropped		TCP connection, allowing the TCP connection to be dropped
	and the session converted to further use in RDMA mode, if		and the session converted to further use in RDMA mode, if
	the server supports that.		the server supports that.
	</t>		</t>
			</section>
	</section>		<section anchor="SEC11-USES-repl" numbered="true" toc="default">
	<section title="File System Replication"		<name>File System Replication</name>
	anchor="SEC11-USES-repl">		<t>
	<t>
	The fs_locations and fs_locations_info attributes provide		The fs_locations and fs_locations_info attributes provide
	alternative file system locations, to be used to access data in place		alternative file system locations, to be used to access data in place
	of or in addition to		of or in addition to
	the current file system instance. On first access to a		the current file system instance. On first access to a
	file system, the client should obtain the set		file system, the client should obtain the set
	of alternate locations by interrogating the fs_locations or		of alternate locations by interrogating the fs_locations or
	fs_locations_info attribute, with the latter being preferred.		fs_locations_info attribute, with the latter being preferred.
	</t>		</t>
	<t>		<t>
	In the event that the occurrence of server failures, communications		In the event that the occurrence of server failures, communications
	problems,		problems,
	or other difficulties make continued access to the current		or other difficulties make continued access to the current
	file system impossible or otherwise impractical, the client		file system impossible or otherwise impractical, the client
	can use the alternate locations as a way to get continued		can use the alternate locations as a way to get continued
	access to its data.		access to its data.
	</t>		</t>
	<t>		<t>
	The alternate locations may be physical replicas of the		The alternate locations may be physical replicas of the
	(typically read-only) file system data supplemented by		(typically read-only) file system data supplemented by
	possible asynchronous propagation of updates. Alternatively,		possible asynchronous propagation of updates. Alternatively,
	they may		they may provide for the use of various forms of server
	provide
	for the use of various forms of server
	clustering in which multiple servers provide alternate		clustering in which multiple servers provide alternate
	ways of accessing the same physical file system. How the		ways of accessing the same physical file system. How the
	difference between replicas affects file system transitions		difference between replicas affects file system transitions
	can be represented		can be represented within the fs_locations and fs_locations_info
	within the fs_locations and fs_locations_info attributes		attributes, and how the client deals with file system transition
	and how the client deals with		issues will be discussed in detail in later sections.
	file system transition issues will be discussed in detail in		</t>
	later sections.		<t>
	</t>
	<t>
	Although the location attributes provide some information about		Although the location attributes provide some information about
	the nature of the inter-replica transition, many aspects of the		the nature of the inter-replica transition, many aspects of the
	semantics of possible asynchronous updates are not currently described		semantics of possible asynchronous updates are not currently described
	by the protocol, making it necessary that clients using replication		by the protocol, which makes it necessary for clients using replication
	to switch among replicas undergoing change familiarize themselves		to switch among replicas undergoing change to familiarize themselves
	with the semantics of the update approach used. Because of this		with the semantics of the update approach used.
	lack of specificity, many applications may find use of migration more		Due to this lack of specificity, many applications may find the
	appropriate, since, in that case, the server, when effecting the		use of migration more appropriate because a server can propagate
	transition, has established a point in time such that all updates made		all updates made before an established point in time to the new
	before that can propagated to the new replica as part of the migration		replica as part of the migration event.
	event.		</t>
	</t>		<section anchor="SEC11-USES-repl-trunk" numbered="true" toc="default">
	<section title="File System Trunking Presented as Replication"		<name>File System Trunking Presented as Replication</name>
	anchor="SEC11-USES-repl-trunk">		<t>
	<t>
	In some situations, a file system location entry may indicate		In some situations, a file system location entry may indicate
	a file system access path to be used as an alternate location,		a file system access path to be used as an alternate location,
	where trunking, rather than replication, is to be used. The		where trunking, rather than replication, is to be used. The
	situations in which this is appropriate are limited to those		situations in which this is appropriate are limited to those
	in which both of the following are true.		in which both of the following are true:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The two file system locations (i.e., the one on which the		The two file system locations (i.e., the one on which the
	location attribute is obtained and the one specified in the		location attribute is obtained and the one specified in the
	file system location entry) designate the same locations within		file system location entry) designate the same locations within
	their respective single-server namespaces.		their respective single-server namespaces.
	</t>		</li>
	<t>		<li>
	The two server network addresses (i.e., the one being used to		The two server network addresses (i.e., the one being used to
	obtain		obtain the location attribute and the one specified in the file syste
	the location attribute and the one specified in the file system		m
	location entry) designate the same server (as indicated by the		location entry) designate the same server (as indicated by the
	same value of the so_major_id field of the eir_server_owner field		same value of the so_major_id field of the eir_server_owner field
	returned in response to EXCHANGE_ID).		returned in response to EXCHANGE_ID).
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	When these conditions hold, operations using both access paths are		When these conditions hold, operations using both access paths are
	generally trunked, although, when the attribute fs_locations_info		generally trunked, although trunking may be disallowed when the
	is used, trunking may be disallowed:		attribute fs_locations_info is used:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	When the fs_locations_info attribute shows the two entries		When the fs_locations_info attribute shows the two entries
	as not having the same simultaneous-use class, trunking is		as not having the same simultaneous-use class, trunking is
	inhibited and the two access paths cannot be used together.		inhibited, and the two access paths cannot be used together.
	<vspace blankLines="1"/>		</t>
	In this case the two paths can be used serially with		<t>
	no transition activity required on the part of the client. In		In this case, the two paths can be used serially with no
	this case, any transition between access paths is transparent,		transition activity required on the part of the client, and any
	and the client, in transferring access from one to the other, is		transition between access paths is transparent. In transferring
	acting as it would in the event that communication is interrupted,		access from one to the other, the client acts as if communication
	with a new connection and possibly a new session being established		were interrupted, establishing a new connection and possibly a
	to continue access to the same file system.		new session to continue access to the same file system.
	</t>		</t>
	<t>		</li>
			<li>
	Note that for two such location entries, any information within		Note that for two such location entries, any information within
	the fs_locations_info attribute that indicates the need for special		the fs_locations_info attribute that indicates the need for special
	transition activity, i.e., the appearance of the two file system		transition activity, i.e., the appearance of the two file system
	location entries with different handle, fileid, write-verifier,		location entries with different handle, fileid, write-verifier,
	change, and readdir classes, indicates a serious problem. The		change, and readdir classes, indicates a serious problem. The
	client, if it allows transition to the file system instance at		client, if it allows transition to the file system instance at
	all, must not treat any transition as a transparent one.		all, must not treat any transition as a transparent one.
	The server SHOULD NOT indicate that these two entries (for the		The server <bcp14>SHOULD NOT</bcp14> indicate that these two entries (for the
	same file system on the same server) belong to		same file system on the same server) belong to
	different handle, fileid, write-verifier, change, and readdir		different handle, fileid, write-verifier, change, and readdir
	classes, whether or not the two entries are shown belonging to		classes, whether or not the two entries are shown belonging to
	the same simultaneous-use class.		the same simultaneous-use class.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		These situations were recognized by <xref target="RFC5661" format="def
	These situations were recognized by <xref target="RFC5661"/>,		ault"/>,
	even though		even though that document made no explicit mention of trunking:
	that document made no explicit mention of trunking.		</t>
	<list style="symbols">		<ul spacing="normal">
	<t>		<li>
	It treated the situation that we describe as trunking as one		It treated the situation that we describe as trunking as one
	of simultaneous use of two distinct file system instances,		of simultaneous use of two distinct file system instances,
	even though, in the explanatory framework now used to		even though, in the explanatory framework now used to
	describe the situation, the case is one in which a single file		describe the situation, the case is one in which a single file
	system is accessed by two different trunked addresses.		system is accessed by two different trunked addresses.
	</t>		</li>
	<t>		<li>
	It treated the situation in which two paths are to be used		It treated the situation in which two paths are to be used
	serially as a special sort of "transparent transition". however,		serially as a special sort of "transparent transition". However,
	in the descriptive framework now used to categorize transition		in the descriptive framework now used to categorize transition
	situations, this is considered a case of a "network endpoint		situations, this is considered a case of a "network endpoint
	transition"		transition" (see <xref target="SEC11-trans-oview" format="default"/>)
	(see <xref target="SEC11-trans-oview"/>).		.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="SEC11-USES-migr" numbered="true" toc="default">
	<section title="File System Migration"		<name>File System Migration</name>
	anchor="SEC11-USES-migr">		<t>
	<t>
	When a file system is present and becomes inaccessible using the		When a file system is present and becomes inaccessible using the
	current access path, the NFSv4.1		current access path, the NFSv4.1 protocol provides a means by
	protocol provides a means by which clients can be given the		which clients can be given the opportunity to have continued access to t
	opportunity to have continued access to their data. This may		heir data.
	involve use of a different access path to the existing replica or		This may involve using a different access path to the existing replica o
	by providing a path to a different replica. The new access path or		r
	the location of the new replica is specified		providing a path to a different replica. The new access path or
	by a file system		the location of the new replica is specified by a file system
	location attribute.		location attribute. The ensuing migration of access includes
	The ensuing migration of access includes		the ability to retain locks across the transition. Depending on circumst
	the ability		ances,
	to retain locks across the transition. Depending on circumstances,
	this can involve:		this can involve:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The continued use of the existing clientid when accessing		The continued use of the existing clientid when accessing
	the current		the current replica using a new access path.
	replica using a new access path.		</li>
	</t>		<li>
	<t>
	Use of lock reclaim, taking advantage of a per-fs grace period.		Use of lock reclaim, taking advantage of a per-fs grace period.
	</t>		</li>
	<t>		<li>
	Use of Transparent State Migration.		Use of Transparent State Migration.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Typically, a client will be		Typically, a client will be
	accessing the file system in question, get an NFS4ERR_MOVED		accessing the file system in question, get an NFS4ERR_MOVED
	error, and then use a file system location attribute		error, and then use a file system location attribute
	to determine the new access path for the data. When		to determine the new access path for the data. When
	fs_locations_info is used, additional information will be		fs_locations_info is used, additional information will be
	available that will define the nature of the client's		available that will define the nature of the client's
	handling of the transition to a new server.		handling of the transition to a new server.
	</t>		</t>
	<t>		<t>
	In most instances, servers will choose to migrate all clients using		In most instances, servers will choose to migrate all clients using
	a particular file system to a successor replica at the same time		a particular file system to a successor replica at the same time
	to avoid cases in which different clients are updating different		to avoid cases in which different clients are updating different
	replicas. However migration of individual client can be helpful		replicas. However, migration of an individual client can be helpful
	in providing load balancing, as long as the replicas in question		in providing load balancing, as long as the replicas in question
	are such that they represent the same data as described in		are such that they represent the same data as described in
	<xref target="SEC11-EFF-data"/>.		<xref target="SEC11-EFF-data" format="default"/>.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	In the case in which there is no transition between replicas (i.e.,		In the case in which there is no transition between replicas (i.e.,
	only a change in access path), there are no special		only a change in access path), there are no special
	difficulties in using of this		difficulties in using of this mechanism to effect load balancing.
	mechanism to effect load balancing.		</li>
	</t>		<li>
	<t>		In the case in which the two replicas are sufficiently coordinated
	In the case in which the two replicas are sufficiently co-ordinated		as to allow a single client coherent, simultaneous access to both,
	as to allow coherent simultaneous access to both by a single client,		there is, in general, no obstacle to the use of migration of particular
	there is, in general, no obstacle to use of migration of particular
	clients to effect load balancing. Generally, such simultaneous use		clients to effect load balancing. Generally, such simultaneous use
	involves co-operation between servers to ensure that locks granted		involves cooperation between servers to ensure that locks granted
	on two co-ordinated replicas cannot conflict and can remain effective		on two coordinated replicas cannot conflict and can remain effective
	when transferred to a common replica.		when transferred to a common replica.
	</t>		</li>
	<t>		<li>
	In the case in which a large set of clients are accessing a		In the case in which a large set of clients is accessing a
	file system in a read-only fashion, in can be helpful to migrate		file system in a read-only fashion, it can be helpful to migrate
	all clients with writable access simultaneously, while using		all clients with writable access simultaneously, while using
	load balancing on the set of read-only copies, as long as the		load balancing on the set of read-only copies, as long as the
	rules appearing in <xref target="SEC11-EFF-data"/>, designed to		rules in <xref target="SEC11-EFF-data" format="default"/>,
	prevent data reversion are adhered to.		which are designed to prevent data reversion, are followed.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	In other cases, the client might not have sufficient guarantees		In other cases, the client might not have sufficient guarantees
	of data similarity/coherence to function properly (e.g. the data		of data similarity or coherence to function properly (e.g., the data
	in the two replicas is similar but not identical), and the		in the two replicas is similar but not identical), and the
	possibility that different clients are updating different replicas		possibility that different clients are updating different replicas
	can exacerbate the difficulties, making use of load balancing in		can exacerbate the difficulties, making the use of load balancing in
	such situations a perilous enterprise.		such situations a perilous enterprise.
	</t>		</t>
	<t>		<t>
	The protocol		The protocol does not specify how the file system will be moved between
	does not specify how the file system will be moved between		servers or how updates to multiple replicas will be coordinated.
	servers or how updates to multiple replicas will be co-ordinated.
	It is anticipated that a number of different		It is anticipated that a number of different
	server-to-server co-ordination mechanisms might be used with the		server-to-server coordination mechanisms might be used, with the
	choice left to the server implementer. The NFSv4.1 protocol		choice left to the server implementer. The NFSv4.1 protocol
	specifies the method used to communicate the migration		specifies the method used to communicate the migration
	event between client and server.		event between client and server.
	</t>		</t>
	<t>		<t>
	The new location may be, in the case of		In the case of various forms of server clustering, the new location
	various forms of server		may be another server providing access to the same physical file system.
	clustering, another server providing		The client's
	access to the same physical file system. The client's
	responsibilities in dealing with this transition will depend		responsibilities in dealing with this transition will depend
	on whether a switch between replicas has occurred and		on whether a switch between replicas has occurred and
	the means the server		the means the server has chosen to provide continuity of locking state.
	has chosen to provide continuity of locking state.		These issues will be discussed in detail below.
	These issues will be discussed in		</t>
	detail below.		<t>
	</t>
	<t>
	Although a single successor location is typical, multiple		Although a single successor location is typical, multiple
	locations may be provided. When multiple locations are		locations may be provided. When multiple locations are
	provided, the client will typically use the first one provided.		provided, the client will typically use the first one provided.
	If that is		If that is inaccessible for some reason, later ones can be used. In such
	inaccessible for some reason, later ones can be used. In such		cases, the client might consider the transition to the new
	cases the client might consider the transition to the new
	replica to be a migration event, even though some of the servers		replica to be a migration event, even though some of the servers
	involved might not be aware of the use of the server which was		involved might not be aware of the use of the server that was
	inaccessible. In such a case, a client might lose access to		inaccessible. In such a case, a client might lose access to
	locking state as a result of the access transfer.		locking state as a result of the access transfer.
	</t>		</t>
	<t>		<t>
	When an alternate location is designated as the target for		When an alternate location is designated as the target for
	migration, it must designate the same data		migration, it must designate the same data
	(with metadata being the same to the degree indicated by the		(with metadata being the same to the degree indicated by the
	fs_locations_info attribute). Where file systems are writable,		fs_locations_info attribute). Where file systems are writable,
	a change made on the original file system must be visible on		a change made on the original file system must be visible on
	all migration targets. Where a file system is not writable		all migration targets. Where a file system is not writable
	but represents a read-only copy (possibly periodically		but represents a read-only copy (possibly periodically
	updated) of		updated) of
	a writable file system, similar requirements apply to the		a writable file system, similar requirements apply to the
	propagation of updates. Any change visible in the original		propagation of updates. Any change visible in the original
	file system must already be effected on all migration targets,		file system must already be effected on all migration targets,
	to avoid any possibility that a client,		to avoid any possibility that a client, in effecting a transition to
	in effecting a transition to		the migration target, will see any reversion in file system state.
	the migration target, will see any reversion		</t>
	in file system state.		</section>
	</t>		<section anchor="SEC11-USES-ref" numbered="true" toc="default">
			<name>Referrals</name>
	</section>		<t>
	<section title="Referrals"
	anchor="SEC11-USES-ref">
	<t>
	Referrals allow the server to associate a file system namespace		Referrals allow the server to associate a file system namespace
	entry located on		entry located on one server with a file system located on another server.
	one server with a file system located on another server.
	When this includes		When this includes
	the use of pure referrals, servers are provided a way of		the use of pure referrals, servers are provided a way of
	placing a file system in a location		placing a file system in a location within the namespace
	within the namespace
	essentially without respect to its physical location on a		essentially without respect to its physical location on a
	particular server.		particular server. This allows a single server or a set of servers
	This allows a single server or a set of servers
	to present a multi-server namespace that encompasses file systems		to present a multi-server namespace that encompasses file systems
	located on a wider range of		located on a wider range of servers. Some likely uses of this facility
	servers. Some likely uses of this facility include		include
	establishment of site-wide or organization-wide namespaces,		establishment of site-wide or organization-wide namespaces,
	with the eventual possibility of combining such		with the eventual possibility of combining such
	together into a truly global namespace, such as the one		together into a truly global namespace, such as the one
	provided by AFS (the Andrew File System) <xref target="AFS"/>.		provided by AFS (the Andrew File System) <xref target="AFS" format="defau
	</t>		lt"/>.
	<t>		</t>
			<t>
	Referrals occur when a client determines, upon first referencing		Referrals occur when a client determines, upon first referencing
	a position in the current namespace, that it is part of a new		a position in the current namespace, that it is part of a new
	file system and that the file system is absent. When this		file system and that the file system is absent. When this
	occurs, typically upon receiving the error NFS4ERR_MOVED, the		occurs, typically upon receiving the error NFS4ERR_MOVED, the
	actual location or locations of the file system can be		actual location or locations of the file system can be
	determined by fetching a locations attribute.		determined by fetching a locations attribute.
	</t>		</t>
	<t>		<t>
	The file system location attribute may designate a single		The file system location attribute may designate a single
	file system location or multiple file system locations, to		file system location or multiple file system locations, to
	be selected based on the needs of the client. The server,		be selected based on the needs of the client. The server,
	in the fs_locations_info attribute, may specify priorities to		in the fs_locations_info attribute, may specify priorities to
	be associated with various file system location choices.		be associated with various file system location choices.
	The server may assign different priorities to different		The server may assign different priorities to different
	locations as reported to individual clients, in order to		locations as reported to individual clients, in order to
	adapt to client physical location or to effect load balancing.		adapt to client physical location or to effect load balancing.
	When both read-only and read-write file systems are present,		When both read-only and read-write file systems are present,
	some of the read-only locations might not be absolutely up-to-date		some of the read-only locations might not be absolutely up-to-date
	(as they would have to be in the case of replication and		(as they would have to be in the case of replication and
	migration). Servers may also specify file system locations		migration). Servers may also specify file system locations
	that include client-substituted variables so that different		that include client-substituted variables so that different
	clients are referred to different file systems (with different		clients are referred to different file systems (with different
	data contents) based on client attributes such as CPU		data contents) based on client attributes such as CPU
	architecture.		architecture.
	</t>		</t>
	<t>		<t>
	When the fs_locations_info attribute is such that that there are		If the fs_locations_info attribute lists multiple possible targets,
	multiple possible targets listed, the relationships among them		the relationships among them may be important to the client in
	may be important to the client in selecting which one to use.		selecting which one to use.
	The same rules specified in <xref target="SEC11-USES-migr"/>		The same rules specified in <xref target="SEC11-USES-migr" format="defau
			lt"/>
	below regarding multiple migration targets		below regarding multiple migration targets
	apply to these multiple replicas as well. For example, the		apply to these multiple replicas as well. For example, the
	client might prefer a writable target on a server that has		client might prefer a writable target on a server that has
	additional writable		additional writable
	replicas to which it subsequently might switch. Note that,		replicas to which it subsequently might switch. Note that,
	as distinguished from the case of replication, there is no		as distinguished from the case of replication, there is no
	need to deal with the case of propagation of updates made by		need to deal with the case of propagation of updates made by
	the current client, since the current client has not accessed		the current client, since the current client has not accessed
	the file system in question.		the file system in question.
	</t>		</t>
	<t>		<t>
	Use of multi-server namespaces is enabled by NFSv4.1 but is not		Use of multi-server namespaces is enabled by NFSv4.1 but is not
	required. The use of multi-server namespaces and their scope		required. The use of multi-server namespaces and their scope
	will depend on the applications used and system administration		will depend on the applications used and system administration
	preferences.		preferences.
	</t>		</t>
	<t>		<t>
	Multi-server namespaces can be established by a single		Multi-server namespaces can be established by a single
	server providing a large set of pure referrals to all of the		server providing a large set of pure referrals to all of the
	included file systems. Alternatively, a single multi-server		included file systems. Alternatively, a single multi-server
	namespace may be administratively segmented with separate		namespace may be administratively segmented with separate
	referral file systems (on separate servers) for each		referral file systems (on separate servers) for each
	separately administered portion of the namespace. The		separately administered portion of the namespace. The
	top-level referral file system or any segment may use		top-level referral file system or any segment may use
	replicated referral file systems for higher availability.		replicated referral file systems for higher availability.
	</t>		</t>
	<t>		<t>
	Generally, multi-server namespaces are for the most part		Generally, multi-server namespaces are for the most part
	uniform, in that the same data made available to one client		uniform, in that the same data made available to one client
	at a given location in the namespace is made available to		at a given location in the namespace is made available to
	all clients at that namespace location. However,		all clients at that namespace location. However,
	there are facilities		there are facilities
	provided that allow different clients to be directed to		provided that allow different clients to be directed to
	different sets of data, for reasons such as enabling		different sets of data, for reasons such as enabling
	adaptation to such client		adaptation to such client
	characteristics as CPU architecture. These facilities are		characteristics as CPU architecture. These facilities are
	described in		described in
	<xref target="SEC11-fsli-item"/>.		<xref target="SEC11-fsli-item" format="default"/>.
	</t>		</t>
	<t>		<t>
	Note that it is possible, when providing a uniform namespace,		Note that it is possible, when providing a uniform namespace,
	to provide different location entries to different clients, in		to provide different location entries to different clients in
	order to provide each client with a copy of the data physically		order to provide each client with a copy of the data physically
	closest to it, or otherwise optimize access (e.g. provide load		closest to it or otherwise optimize access (e.g., provide load
	balancing).		balancing).
	</t>		</t>
			</section>
	</section>		<section anchor="SEC11-USES-changes" numbered="true" toc="default">
	<section title="Changes in a File System Location Attribute"		<name>Changes in a File System Location Attribute</name>
	anchor="SEC11-USES-changes">		<t>
	<t>		Although clients will typically fetch a file system location attribute
	Although clients will typically fetch a file system
	location attribute
	when first accessing a file system and when NFS4ERR_MOVED		when first accessing a file system and when NFS4ERR_MOVED
	is returned, a client can choose to fetch the attribute		is returned, a client can choose to fetch the attribute
	periodically, in which case the value fetched may change over		periodically, in which case, the value fetched may change over time.
	time.		</t>
	</t>
	<t>
	For clients not prepared to access multiple
	replicas simultaneously (see
	<xref target="SEC11-EFF-simul"/>),
	the handling of the various cases of location change are as follows:
	<list style="symbols">
	<t>		<t>
			For clients not prepared to access multiple replicas simultaneously (see
			<xref target="SEC11-EFF-simul" format="default"/>),
			the handling of the various cases of location change are as follows:
			</t>
			<ul spacing="normal">
			<li>
	Changes in the list of replicas or in the network addresses		Changes in the list of replicas or in the network addresses
	associated with replicas do not require immediate action.		associated with replicas do not require immediate action.
	The client will typically update its list of replicas to		The client will typically update its list of replicas to
	reflect the new information.		reflect the new information.
	</t>		</li>
	<t>		<li>
	Additions to the list of network addresses for the		Additions to the list of network addresses for the
	current file system instance need not be acted		current file system instance need not be acted
	on promptly. However, to prepare for the case in which		on promptly. However, to prepare for a subsequent
	a migration event occurs subsequently, the client can choose		migration event, the client can choose
	to take note of the new address and then use it		to take note of the new address and then use it
	whenever it needs to switch access to a new		whenever it needs to switch access to a new replica.
	replica.		</li>
	</t>		<li>
	<t>
	Deletions from the list of network addresses for the		Deletions from the list of network addresses for the
	current file system instance do not need to be acted on		current file system instance do not require the client to immediately
	immediately		cease use of existing access paths, although new connections
	by ceasing use of existing access paths although new connections
	are not to be established on addresses that have been deleted.		are not to be established on addresses that have been deleted.
	However, clients can choose to act on such deletions		However, clients can choose to act on such deletions
	by making preparations for an eventual shift in access which		by preparing for an eventual shift in access, which
	would become unavoidable as soon as the		becomes unavoidable as soon as the server returns
	server indicates that a particular network access path is		NFS4ERR_MOVED to indicate that a particular network access path is
	not usable to access the current file system,		not usable to access the current file system.
	by returning NFS4ERR_MOVED.		</li>
	</t>		</ul>
	</list>		<t>
	</t>		For clients that are prepared to access several replicas simultaneously,
	<t>
	For clients that are prepared to access several replicas
	simultaneously,
	the following additional cases need to be addressed. As in		the following additional cases need to be addressed. As in
	the cases discussed above, changes in the set of replicas		the cases discussed above, changes in the set of replicas
	need not be acted upon promptly, although the client has		need not be acted upon promptly, although the client has
	the option of adjusting its access even in the absence of		the option of adjusting its access even in the absence of
	difficulties that would lead to a new replica to be selected.		difficulties that would lead to the selection of a new replica.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	When a new replica is added which may be accessed		<li>
			When a new replica is added, which may be accessed
	simultaneously with one currently in use, the client is free		simultaneously with one currently in use, the client is free
	to use the new replica immediately.		to use the new replica immediately.
	</t>		</li>
	<t>		<li>
	When a replica currently in use is deleted from the list, the		When a replica currently in use is deleted from the list, the
	client need not cease using it immediately. However, since		client need not cease using it immediately. However, since
	the server may subsequently force such use to cease (by		the server may subsequently force such use to cease (by
	returning NFS4ERR_MOVED), clients might decide to limit the		returning NFS4ERR_MOVED), clients might decide to limit the
	need for later state transfer. For example, new opens might		need for later state transfer. For example, new opens might
	be done on other replicas, rather than on one not present in		be done on other replicas, rather than on one not present in
	the list.		the list.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="SEC11-TRUNK" numbered="true" toc="default">
	<section title="Trunking without File System Location Information"		<name>Trunking without File System Location Information</name>
	anchor="SEC11-TRUNK">		<t>
	<t>
	In situations in which a file system is accessed using two		In situations in which a file system is accessed using two
	server-trunkable addresses (as indicated by the same value of the		server-trunkable addresses (as indicated by the same value of the
	so_major_id field of the eir_server_owner field returned in		so_major_id field of the eir_server_owner field returned in
	response to EXCHANGE_ID), trunked access is allowed even though		response to EXCHANGE_ID), trunked access is allowed even though
	there might not be any location entries specifically indicating		there might not be any location entries specifically indicating
	the use of trunking for that file system.		the use of trunking for that file system.
	</t>		</t>
	<t>		<t>
	This situation was recognized by <xref target="RFC5661"/>, even though		This situation was recognized by <xref target="RFC5661" format="default"/>
			, although
	that document made no explicit mention of trunking and treated the		that document made no explicit mention of trunking and treated the
	situation as one of simultaneous use of two distinct file system		situation as one of simultaneous use of two distinct file system
	instances, even though, in the explanatory framework now used to		instances. In the explanatory framework now used to
	describe the situation, the case is one in which a single file		describe the situation, the case is one in which a single file
	system is accessed by two different trunked addresses.		system is accessed by two different trunked addresses.
	</t>		</t>
	</section>		</section>
			<section anchor="SEC11-users" numbered="true" toc="default">
	<section title="Users and Groups in a Multi-server Namespace"		<name>Users and Groups in a Multi-Server Namespace</name>
	anchor="SEC11-users">		<t>
	<t>
	As in the case of a single-server environment (see		As in the case of a single-server environment (see
	<xref target="owner_owner_group"/>,		<xref target="owner_owner_group" format="default"/>),
	when an owner or group name of the form "id@domain" is assigned to		when an owner or group name of the form "id@domain" is assigned to
	a file, there is an implicit promise to return that same string when		a file, there is an implicit promise to return that same string when
	the corresponding attribute is interrogated subsequently. In the		the corresponding attribute is interrogated subsequently. In the
	case of a multi-server namespace, that same promise applies even if		case of a multi-server namespace, that same promise applies even if
	server boundaries have been crossed. Similarly, when the owner		server boundaries have been crossed. Similarly, when the owner
	attribute of a file is derived from the security principal which created		attribute of a file is derived from the security principal that created
	the file, that attribute should have the same value even if the		the file, that attribute should have the same value even if the
	interrogation occurs on a different server from the file creation.		interrogation occurs on a different server from the file creation.
	</t>		</t>
	<t>		<t>
	Similarly, the set of security principals recognized by all the		Similarly, the set of security principals recognized by all the
	participating servers needs to be the same, with each such principal		participating servers needs to be the same, with each such principal
	having the same credentials, regardless of the particular server		having the same credentials, regardless of the particular server
	being accessed.		being accessed.
	</t>		</t>
	<t>		<t>
	In order to meet these requirements, those setting up multi-server		In order to meet these requirements, those setting up multi-server
	namespaces will need to limit the servers included so that:		namespaces will need to limit the servers included so that:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	In all cases in which more than a single domain is supported,		In all cases in which more than a single domain is supported,
	the requirements stated in RFC8000 <xref target="RFC8000"/>		the requirements stated in RFC 8000 <xref target="RFC8000" format="defaul t"/>
	are to be respected.		are to be respected.
	</t>		</li>
	<t>		<li>
	All servers support a common set of domains which includes all of		All servers support a common set of domains that includes all of
	the domains clients use and expect to see returned as the domain		the domains clients use and expect to see returned as the domain
	portion of an owner or group in the form "id@domain". Note that		portion of an owner or group in the form "id@domain". Note that,
	although this set most often consists of a single domain, it is		although this set most often consists of a single domain, it is
	possible for multiple domains to be supported.		possible for multiple domains to be supported.
	</t>		</li>
	<t>		<li>
	All servers, for each domain that they support, accept the same set		All servers, for each domain that they support, accept the same set
	of user and group ids as valid.		of user and group ids as valid.
	</t>		</li>
	<t>		<li>
	All servers recognize the same set of security principals. For each		All servers recognize the same set of security principals. For each
	principal, the same credential is required, independent of the		principal, the same credential is required, independent of the
	server being accessed. In addition, the group membership for each such		server being accessed. In addition, the group membership for each such
	principal is to be the same, independent of the server accessed.		principal is to be the same, independent of the server accessed.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		Note that there is no requirement in general that the users
	Note that there is no requirement in general that the users		corresponding to particular security principals have the same local
	corresponding to		representation on each server, even though it is most often the case that
	particular security principals have the same local		this is so.
	representation on each server,		</t>
	even though it is most often the case that this is so.		<t>
	</t>		When AUTH_SYS is used, the following additional requirements must be met:
	<t>		</t>
	When AUTH_SYS is used, the following additional requirements must be		<ul spacing="normal">
	met:		<li>
	<list style="symbols">		Only a single NFSv4 domain can be supported through the use of AUTH_SYS.
	<t>		</li>
	Only a single NFSv4 domain can be supported through use of AUTH_SYS.		<li>
	</t>
	<t>
	The "local" representation of all owners and groups must be the same		The "local" representation of all owners and groups must be the same
	on all servers. The word "local" is used here since that is the		on all servers. The word "local" is used here since that is the
	way that numeric user and group ids are described in		way that numeric user and group ids are described in
	<xref target="owner_owner_group"/>. However,		<xref target="owner_owner_group" format="default"/>. However,
	when AUTH_SYS or stringified numeric owners or		when AUTH_SYS or stringified numeric owners or
	groups are used, these identifiers are not truly local, since they		groups are used, these identifiers are not truly local, since they
	are known to the clients as well as the server.		are known to the clients as well as to the server.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Similarly, when stringified numeric user and group ids are used, the		Similarly, when stringified numeric user and group ids are used, the
	"local" representation of all owners and groups must be the same on		"local" representation of all owners and groups must be the same on
	all servers, even when AUTH_SYS is not used.		all servers, even when AUTH_SYS is not used.
	</t>		</t>
	</section>		</section>
	<section title="Additional Client-Side Considerations"		<section anchor="SEC11-csr" numbered="true" toc="default">
	anchor="SEC11-csr">		<name>Additional Client-Side Considerations</name>
	<t>		<t>
	When clients make use of servers that implement referrals,		When clients make use of servers that implement referrals,
	replication, and		replication, and
	migration, care should be taken that a user who mounts a given		migration, care should be taken that a user who mounts a given
	file system that includes a referral or a relocated file system		file system that includes a referral or a relocated file system
	continues to see a coherent picture of that user-side file system		continues to see a coherent picture of that user-side file system
	despite the fact that it contains a number of server-side		despite the fact that it contains a number of server-side
	file systems that may be on different servers.		file systems that may be on different servers.
	</t>		</t>
	<t>		<t>
	One important issue is upward navigation from the root of a		One important issue is upward navigation from the root of a
	server-side file system to its parent (specified as ".." in UNIX),		server-side file system to its parent (specified as ".." in UNIX),
	in the case in which it transitions to that file system as a		in the case in which it transitions to that file system as a
	result of referral, migration, or a transition as a result of		result of referral, migration, or a transition as a result of
	replication. When the client is at such a point, and it needs to ascend t o		replication. When the client is at such a point, and it needs to ascend t o
	the parent, it must go back to the parent as seen within the		the parent, it must go back to the parent as seen within the
	multi-server namespace rather than sending a LOOKUPP operation to the		multi-server namespace rather than sending a LOOKUPP operation to the
	server, which would result in the parent within that server's		server, which would result in the parent within that server's
	single-server namespace. In order to do this, the client		single-server namespace. In order to do this, the client
	needs to remember the filehandles that represent such		needs to remember the filehandles that represent such
	file system roots and use these instead of sending a		file system roots and use these instead of sending a
	LOOKUPP operation to the current server. This will allow the client		LOOKUPP operation to the current server. This will allow the client
	to present to applications a consistent namespace, where		to present to applications a consistent namespace, where
	upward navigation and downward navigation are consistent.		upward navigation and downward navigation are consistent.
	</t>		</t>
	<t>		<t>
	Another issue concerns refresh of referral locations. When		Another issue concerns refresh of referral locations. When
	referrals are used extensively, they may change as server		referrals are used extensively, they may change as server
	configurations change. It is expected that clients will cache		configurations change. It is expected that clients will cache
	information related to traversing referrals so that future		information related to traversing referrals so that future
	client-side requests are resolved locally without server		client-side requests are resolved locally without server
	communication.		communication.
	This is usually rooted in client-side name look up caching. Clients		This is usually rooted in client-side name look up caching. Clients
	should periodically purge this data for referral points in order to		should periodically purge this data for referral points in order to
	detect changes in location information. When the change_policy		detect changes in location information. When the change_policy
	attribute changes for directories that hold referral entries		attribute changes for directories that hold referral entries
	or for the referral entries themselves, clients should consider		or for the referral entries themselves, clients should consider
	any associated		any associated
	cached referral information to be out of date.		cached referral information to be out of date.
	</t>		</t>
	</section>		</section>
	<section title="Overview of File Access Transitions"		<section anchor="SEC11-trans-oview" numbered="true" toc="default">
	anchor="SEC11-trans-oview">		<name>Overview of File Access Transitions</name>
	<t>		<t>
	File access transitions are of two types:		File access transitions are of two types:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Those that involve a transition from accessing the current		Those that involve a transition from accessing the current
	replica to another one in connection with either		replica to another one in connection with either replication or migratio
	replication or migration.		n.
	How these are dealt with is discussed in		How these are dealt with is discussed in
	<xref target="SEC11-EFF"/>.		<xref target="SEC11-EFF" format="default"/>.
	</t>		</li>
	<t>		<li>
	Those in which access to the current file system instance		Those in which access to the current file system instance is retained, w
	is retained, while		hile
	the network path used to access that instance is changed.		the network path used to access that instance is changed. This case is
	This case is		discussed in <xref target="SEC11-nwa" format="default"/>.
	discussed in <xref target="SEC11-nwa"/>.		</li>
	</t>		</ul>
	</list>		</section>
	</t>		<section anchor="SEC11-nwa" numbered="true" toc="default">
			<name>Effecting Network Endpoint Transitions</name>
	</section>		<t>
	<section title="Effecting Network Endpoint Transitions"
	anchor="SEC11-nwa">
	<t>
	The endpoints used to access a particular file system instance		The endpoints used to access a particular file system instance
	may change in a number of ways, as listed below. In each of these		may change in a number of ways, as listed below. In each of these
	cases, the same fsid, filehandles, stateids, client IDs and		cases, the same fsid, client IDs, filehandles, and stateids are
	are
	used to continue access, with a continuity of lock state. In		used to continue access, with a continuity of lock state. In
	many cases, the same sessions can also be used.		many cases, the same sessions can also be used.
	</t>		</t>
	<t>		<t>
	The appropriate action depends on the set of replacement addresses		The appropriate action depends on the set of replacement addresses
	(i.e. server endpoints which are server-trunkable with one previously		that are available for use
	being used) which are available for use.		(i.e., server endpoints that are server-trunkable with one previously
	</t>		being used).
	<t>		</t>
	<list style="symbols">		<ul spacing="normal">
	<t>		<li>
	When use of a particular address is to cease and there is		When use of a particular address is to cease, and there is
	also another one		also another address
	currently in use which is server-trunkable with it, requests		currently in use that is server-trunkable with it, requests
	that would have been issued on the address whose use is to be		that would have been issued on the address whose use is to be
	discontinued can be issued on the remaining address(es). When an		discontinued can be issued on the remaining address(es). When an
	address is server-trunkable but not session-trunkable with the		address is server-trunkable but not session-trunkable with the
	address whose use is to be discontinued, the request might need		address whose use is to be discontinued, the request might need
	to be modified to reflect the fact that a different session will		to be modified to reflect the fact that a different session will
	be used.		be used.
	</t>		</li>
	<t>		<li>
	When use of a particular connection is to cease, as indicated		When use of a particular connection is to cease, as indicated
	by receiving NFS4ERR_MOVED when using that connection but		by receiving NFS4ERR_MOVED when using that connection, but
	that address is		that address is
	still indicated as accessible according to the appropriate		still indicated as accessible according to the appropriate
	file system location		file system location
	entries, it is likely that requests can be issued on a new		entries, it is likely that requests can be issued on a new
	connection of a different connection type, once that connection		connection of a different connection type once that connection
	is established. Since any two, non-port-specific		is established.
	server endpoints that share a network address are inherently		Since any two non-port-specific server endpoints that share a
	session-trunkable, the client can use BIND_CONN_TO_SESSION		network address are inherently session-trunkable, the client
	to access the existing session using the new connection and		can use BIND_CONN_TO_SESSION to access the existing session
	proceed to access the file system using the new connection.		with the new connection.
	</t>		</li>
	<t>		<li>
	When there are no potential replacement addresses in use but there		When there are no potential replacement addresses in use, but there
	are valid addresses session-trunkable with the one whose use is		are valid addresses session-trunkable with the one whose use is
	to be discontinued, the client can use BIND_CONN_TO_SESSION		to be discontinued, the client can use BIND_CONN_TO_SESSION
	to access the existing session using the new address. Although		to access the existing session using the new address. Although
	the target session will generally be accessible, there may be		the target session will generally be accessible, there may be
	rare situations in which that session is no longer accessible,		rare situations in which that session is no longer accessible
	when an attempt is made to bind the new connection to it.		when an attempt is made to bind the new connection to it. In this
	In this
	case, the client can create a new session to enable continued		case, the client can create a new session to enable continued
	access to the existing instance using the new connection,		access to the existing instance using the new connection,
	providing for use of existing		providing for the use of existing filehandles, stateids, and
	filehandles, stateids, and client ids while providing continuity		client ids while supplying continuity of locking state.
	of locking state.		</li>
	</t>		<li>
	<t>		When there is no potential replacement address in use, and there
	When there is no potential replacement address in use and there		are no valid addresses session-trunkable with the one whose use is
	are no
	valid addresses session-trunkable with the one whose use is
	to be discontinued, other server-trunkable addresses may be		to be discontinued, other server-trunkable addresses may be
	used to provide continued access. Although use of CREATE_SESSION		used to provide continued access. Although the use of CREATE_SESSION
	is available to provide continued access to the existing instance,		is available to provide continued access to the existing instance,
	servers have the option of providing continued access to the		servers have the option of providing continued access to the
	existing session through the new network access		existing session through the new network access path in a fashion
	path in a fashion similar to		similar to that provided by session migration (see
	that provided by session migration (see		<xref target="SEC11-trans-locking" format="default"/>).
	<xref target="SEC11-trans-locking"/>).
	To take advantage of this		To take advantage of this
	possibility, clients can perform an initial BIND_CONN_TO_SESSION,		possibility, clients can perform an initial BIND_CONN_TO_SESSION,
	as in the previous case, and use CREATE_SESSION only if that		as in the previous case, and use CREATE_SESSION only if that fails.
	fails.		</li>
	</t>		</ul>
	</list>		</section>
	</t>		<section anchor="SEC11-EFF" numbered="true" toc="default">
			<name>Effecting File System Transitions</name>
	</section>		<t>
	<section title="Effecting File System Transitions"
	anchor="SEC11-EFF">
	<t>
	There are a range of situations in which there is a change to be		There are a range of situations in which there is a change to be
	effected in the set of replicas used to access a particular		effected in the set of replicas used to access a particular
	file system. Some of these may involve an expansion or		file system. Some of these may involve an expansion or
	contraction of the set of replicas used as discussed in		contraction of the set of replicas used as discussed in
	<xref target="SEC11-EFF-simul"/> below.		<xref target="SEC11-EFF-simul" format="default"/> below.
	</t>		</t>
	<t>		<t>
	For reasons explained in that section, most transitions will involve		For reasons explained in that section, most transitions will involve
	a transition from a single replica to a corresponding replacement		a transition from a single replica to a corresponding replacement
	replica. When effecting replica transition, some types of		replica. When effecting replica transition, some types of
	sharing between the replicas may affect handling of the		sharing between the replicas may affect handling of the
	transition as described in		transition as described in
	Sections <xref target="SEC11-EFF-fh" format="counter"/>		Sections <xref target="SEC11-EFF-fh" format="counter"/>
	through <xref target="SEC11-EFF-data" format="counter"/> below.		through <xref target="SEC11-EFF-data" format="counter"/> below.
	The attribute fs_locations_info provides helpful information		The attribute fs_locations_info provides helpful information
	to allow the client to determine the degree of inter-replica		to allow the client to determine the degree of inter-replica
	sharing.		sharing.
	</t>		</t>
	<t>		<t>
	With regard to some types of state, the degree of continuity		With regard to some types of state, the degree of continuity
	across the transition		across the transition depends on the occasion prompting the
	depends on the occasion prompting the transition, with		transition, with transitions initiated by the servers
	transitions initiated by the servers		(i.e., migration) offering much more scope for a nondisruptive
	(i.e. migration) offering much more scope for a non-disruptive
	transition than cases in which the client on its own		transition than cases in which the client on its own
	shifts its access to		shifts its access to another replica (i.e., replication).
	another replica (i.e. replication). This issue		This issue potentially applies to locking state and to session
	potentially applies to		state, which are dealt with below as follows:
	locking state and to session state, which are dealt with below as		</t>
	follows:		<ul spacing="normal">
	<list style="symbols">		<li>
	<t>
	An introduction to the possible means of providing continuity in		An introduction to the possible means of providing continuity in
	these areas appears in <xref target="SEC11-EFF-lock"/> below.		these areas appears in <xref target="SEC11-EFF-lock" format="default"/>
	</t>		below.
	<t>		</li>
			<li>
	Transparent State Migration is introduced in		Transparent State Migration is introduced in
	<xref target="SEC11-trans-locking"/>.		<xref target="SEC11-trans-locking" format="default"/>.
	The possible transfer of		The possible transfer of
	session state is addressed there as well.		session state is addressed there as well.
	</t>		</li>
	<t>		<li>
	The client handling of transitions, including determining how to		The client handling of transitions, including determining how to
	deal with the various means that the server might take to		deal with the various means that the server might take to
	supply effective continuity of locking state is discussed in		supply effective continuity of locking state, is discussed in
	<xref target="SEC11-trans-client"/>.		<xref target="SEC11-trans-client" format="default"/>.
	</t>		</li>
	<t>		<li>
	The servers' (source and destination) responsibilities		The source and destination servers' responsibilities
	in effecting Transparent Migration		in effecting Transparent State Migration
	of locking and session state are discussed in		of locking and session state are discussed in
	<xref target="SEC11-trans-server"/>.		<xref target="SEC11-trans-server" format="default"/>.
	</t>		</li>
	</list>		</ul>
	</t>		<section anchor="SEC11-EFF-simul" numbered="true" toc="default">
	<section title="File System Transitions and Simultaneous Access"		<name>File System Transitions and Simultaneous Access</name>
	anchor="SEC11-EFF-simul">		<t>
	<t>
	The fs_locations_info attribute (described in		The fs_locations_info attribute (described in
	<xref target="SEC11-li-new"/>)		<xref target="SEC11-li-new" format="default"/>)
	may indicate that two replicas		may indicate that two replicas
	may be used simultaneously, although some situations in which such		may be used simultaneously, although some situations in which such
	simultaneous access is permitted are more appropriately described		simultaneous access is permitted are more appropriately described
	as instances of trunking (see <xref target="SEC11-USES-repl-trunk"/>).		as instances of trunking (see <xref target="SEC11-USES-repl-trunk" format ="default"/>).
	Although situations		Although situations
	in which multiple replicas may be accessed simultaneously are		in which multiple replicas may be accessed simultaneously are
	somewhat similar to those in which a single replica is		somewhat similar to those in which a single replica is
	accessed by multiple network addresses, there are important		accessed by multiple network addresses, there are important
	differences, since locking state is not shared among multiple		differences since locking state is not shared among multiple
	replicas.		replicas.
	</t>		</t>
	<t>		<t>
	Because of this difference in state handling, many clients will		Because of this difference in state handling, many clients will
	not have the ability to take advantage of the fact that such		not have the ability to take advantage of the fact that such
	replicas represent the same data. Such clients will not be		replicas represent the same data. Such clients will not be
	prepared to use multiple replicas simultaneously but will access		prepared to use multiple replicas simultaneously but will access
	each file system using only a single replica, although the		each file system using only a single replica, although the
	replica selected might make multiple server-trunkable addresses		replica selected might make multiple server-trunkable addresses
	available.		available.
	</t>		</t>
	<t>		<t>
	Clients who are prepared to use multiple replicas simultaneously		Clients who are prepared to use multiple replicas simultaneously
	will divide opens among replicas however they choose. Once that		can divide opens among replicas however they choose. Once that
	choice is made,		choice is made, any subsequent transitions will treat the set of locking
	any subsequent transitions will treat the set of locking
	state associated with each replica as a single entity.		state associated with each replica as a single entity.
	</t>		</t>
	<t>		<t>
	For example, if one of the replicas become unavailable,		For example, if one of the replicas become unavailable, access will be
	access will be		transferred to a different replica, which is also capable of
	transferred to a different replica, also capable of
	simultaneous access with the one still in use.		simultaneous access with the one still in use.
	</t>		</t>
	<t>		<t>
	When there is no such replica, the transition may be to the		When there is no such replica, the transition may be to the
	replica already in use. At this point, the client has a		replica already in use. At this point, the client has a
	choice between merging the locking state for the two replicas		choice between merging the locking state for the two replicas
	under the aegis of the sole replica in use or treating these		under the aegis of the sole replica in use or treating these
	separately, until another replica capable of simultaneous		separately until another replica capable of simultaneous
	access presents itself.		access presents itself.
	</t>		</t>
	</section>		</section>
	<section title="Filehandles and File System Transitions"		<section anchor="SEC11-EFF-fh" numbered="true" toc="default">
	anchor="SEC11-EFF-fh">		<name>Filehandles and File System Transitions</name>
			<t>
	<t>
	There are a number of ways in which filehandles can be handled		There are a number of ways in which filehandles can be handled
	across a file system transition. These can be divided into		across a file system transition. These can be divided into
	two broad classes depending upon whether the two file systems		two broad classes depending upon whether the two file systems
	across which the transition happens share sufficient state to		across which the transition happens share sufficient state to
	effect some sort of continuity of file system handling.		effect some sort of continuity of file system handling.
	</t>		</t>
	<t>		<t>
	When there is no such cooperation in filehandle assignment,		When there is no such cooperation in filehandle assignment,
	the two file systems are reported as being in different		the two file systems are reported as being in different
	handle classes. In this case,		handle classes. In this case,
	all filehandles are assumed to expire as part of the		all filehandles are assumed to expire as part of the
	file system transition. Note that this behavior does not		file system transition. Note that this behavior does not
	depend on the fh_expire_type attribute and supersedes		depend on the fh_expire_type attribute and supersedes
	the specification		the specification
	of the FH4_VOL_MIGRATION bit, which only affects behavior when		of the FH4_VOL_MIGRATION bit, which only affects behavior when
	fs_locations_info is not available.		fs_locations_info is not available.
	</t>		</t>
	<t>		<t>
	When there is cooperation in filehandle assignment,		When there is cooperation in filehandle assignment,
	the two file systems are reported as being in the same		the two file systems are reported as being in the same
	handle classes. In this case,		handle classes. In this case,
	persistent filehandles remain valid after the file system		persistent filehandles remain valid after the file system
	transition, while volatile filehandles (excluding those		transition, while volatile filehandles (excluding those
	that are only volatile due to the FH4_VOL_MIGRATION bit) are		that are only volatile due to the FH4_VOL_MIGRATION bit) are
	subject to expiration on the target server.		subject to expiration on the target server.
	</t>		</t>
	</section>		</section>
	<section title="Fileids and File System Transitions"		<section anchor="SEC11-EFF-fileid" numbered="true" toc="default">
	anchor="SEC11-EFF-fileid">		<name>Fileids and File System Transitions</name>
	<t>		<t>
	In NFSv4.0, the issue of continuity of fileids in the event		In NFSv4.0, the issue of continuity of fileids in the event
	of a file system transition was not addressed. The general		of a file system transition was not addressed. The general
	expectation had been that in situations in		expectation had been that in situations in
	which the two file system instances are created by a single vendor		which the two file system instances are created by a single vendor
	using some sort of file system image copy, fileids would be		using some sort of file system image copy, fileids would be
	consistent across the transition, while in the analogous		consistent across the transition, while in the analogous
	multi-vendor transitions they would not. This poses difficulties,		multi-vendor transitions they would not. This poses difficulties,
	especially for the client without special knowledge		especially for the client without special knowledge
	of the transition mechanisms adopted by the server. Note		of the transition mechanisms adopted by the server. Note
	that although fileid is not a REQUIRED attribute, many servers		that although fileid is not a <bcp14>REQUIRED</bcp14> attribute, many se rvers
	support fileids and many clients provide APIs that depend on fileids.		support fileids and many clients provide APIs that depend on fileids.
	</t>		</t>
	<t>		<t>
	It is important to note that while clients themselves may have no		It is important to note that while clients themselves may have no
	trouble with a fileid changing as a result of a file system		trouble with a fileid changing as a result of a file system
	transition event, applications do typically have access to the		transition event, applications do typically have access to the
	fileid (e.g., via stat). The result is that an		fileid (e.g., via stat). The result is that an
	application may work perfectly well if there is no file system		application may work perfectly well if there is no file system
	instance transition or if any such transition is among instances		instance transition or if any such transition is among instances
	created by a single vendor, yet be unable to deal with the		created by a single vendor, yet be unable to deal with the
	situation in which a multi-vendor transition occurs at the wrong		situation in which a multi-vendor transition occurs at the wrong
	time.		time.
	</t>		</t>
	<t>		<t>
	Providing the same fileids in a multi-vendor (multiple server		Providing the same fileids in a multi-vendor (multiple server
	vendors) environment has generally been held to be quite difficult.		vendors) environment has generally been held to be quite difficult.
	While there is work to be done, it needs to be pointed out that		While there is work to be done, it needs to be pointed out that
	this difficulty is partly self-imposed. Servers have typically		this difficulty is partly self-imposed. Servers have typically
	identified fileid with inode number, i.e. with a quantity used to		identified fileid with inode number, i.e. with a quantity used to
	find the file in question. This identification poses special		find the file in question. This identification poses special
	difficulties for migration of a file system between vendors		difficulties for migration of a file system between vendors
	where assigning		where assigning
	the same index to a given file may not be possible. Note here that		the same index to a given file may not be possible. Note here that
	a fileid is not required to be useful to find the file in		a fileid is not required to be useful to find the file in
	question, only that it is unique within the given file system. Servers		question, only that it is unique within the given file system. Servers
	prepared to accept a fileid as a single piece of metadata and store		prepared to accept a fileid as a single piece of metadata and store
	it apart from the value used to index the file information can		it apart from the value used to index the file information can
	relatively easily maintain a fileid value across a migration event,		relatively easily maintain a fileid value across a migration event,
	allowing a truly transparent migration event.		allowing a truly transparent migration event.
	</t>		</t>
	<t>		<t>
	In any case, where servers can provide continuity of fileids, they		In any case, where servers can provide continuity of fileids, they
	should, and the client should be able to find out that such		should, and the client should be able to find out that such
	continuity is available and take appropriate action. Information		continuity is available and take appropriate action. Information
	about the continuity (or lack thereof) of fileids across a file		about the continuity (or lack thereof) of fileids across a file
	system transition is represented by specifying whether the file systems		system transition is represented by specifying whether the file systems
	in question are of the same fileid class.		in question are of the same fileid class.
	</t>		</t>
	<t>		<t>
	Note that when consistent fileids do not exist across a		Note that when consistent fileids do not exist across a
	transition (either because there is no continuity of fileids		transition (either because there is no continuity of fileids
	or because fileid is not a supported attribute on one of		or because fileid is not a supported attribute on one of
	instances involved), and there are		instances involved), and there are
	no reliable filehandles across a transition event (either because		no reliable filehandles across a transition event (either because
	there is no filehandle continuity or because the filehandles are		there is no filehandle continuity or because the filehandles are
	volatile), the client is in a position where it cannot verify		volatile), the client is in a position where it cannot verify
	that files it was accessing before the transition are the		that files it was accessing before the transition are the
	same objects. It is forced to assume that no object has been		same objects. It is forced to assume that no object has been
	renamed, and, unless there are guarantees that provide this		renamed, and, unless there are guarantees that provide this
	(e.g., the file system is read-only), problems for applications		(e.g., the file system is read-only), problems for applications
	may occur. Therefore, use of such configurations should be		may occur. Therefore, use of such configurations should be
	limited to situations where the problems that this may cause		limited to situations where the problems that this may cause
	can be tolerated.		can be tolerated.
	</t>		</t>
	</section>		</section>
	<section title="Fsids and File System Transitions"		<section anchor="SEC11-EFF-fsid" numbered="true" toc="default">
	anchor="SEC11-EFF-fsid">		<name>Fsids and File System Transitions</name>
	<t>		<t>
	Since fsids are generally only unique on a per-server basis,		Since fsids are generally only unique on a per-server basis,
	it is likely that they will change during a file system		it is likely that they will change during a file system
	transition.		transition.
	Clients should not make the fsids received		Clients should not make the fsids received
	from the server visible to applications since they may not be		from the server visible to applications since they may not be
	globally unique, and because they may change during a file		globally unique, and because they may change during a file
	system transition event. Applications are best served if they		system transition event. Applications are best served if they
	are isolated from such transitions to the extent possible.		are isolated from such transitions to the extent possible.
	</t>		</t>
	<t>		<t>
	Although normally a single source file system will transition		Although normally a single source file system will transition
	to a single target file system, there is a provision for splitting		to a single target file system, there is a provision for splitting
	a single source file system into multiple target file systems, by		a single source file system into multiple target file systems, by
	specifying the FSLI4F_MULTI_FS flag.		specifying the FSLI4F_MULTI_FS flag.
	</t>		</t>
	<section anchor="SEC11-EFF-fsid-split"		<section anchor="SEC11-EFF-fsid-split" numbered="true" toc="default">
	title="File System Splitting">		<name>File System Splitting</name>
	<t>		<t>
	When a file system transition is made and the fs_locations_info		When a file system transition is made and the fs_locations_info
	indicates that the file system in question might be split into		indicates that the file system in question might be split into
	multiple file systems (via the FSLI4F_MULTI_FS flag), the client		multiple file systems (via the FSLI4F_MULTI_FS flag), the client
	SHOULD do GETATTRs to determine the fsid attribute on all known		<bcp14>SHOULD</bcp14> do GETATTRs to determine the fsid attribute on a ll known
	objects within the file system undergoing transition to determine		objects within the file system undergoing transition to determine
	the new file system boundaries.		the new file system boundaries.
	</t>		</t>
	<t>		<t>
	Clients might choose to		Clients might choose to
	maintain the fsids passed to existing applications		maintain the fsids passed to existing applications
	by mapping all of the fsids for the descendant file systems to		by mapping all of the fsids for the descendant file systems to
	the common fsid used for the original file system.		the common fsid used for the original file system.
	</t>		</t>
	<t>		<t>
	Splitting a file system can be done on a transition between		Splitting a file system can be done on a transition between
	file systems of the same fileid		file systems of the same fileid
	class, since the fact that fileids are unique within the		class, since the fact that fileids are unique within the
	source file system ensure they will be unique in each of the		source file system ensure they will be unique in each of the
	target file systems.		target file systems.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section anchor="SEC11-EFF-change"		<section anchor="SEC11-EFF-change" numbered="true" toc="default">
	title="The Change Attribute and File System Transitions">		<name>The Change Attribute and File System Transitions</name>
	<t>		<t>
	Since the change attribute is defined as a server-specific one,		Since the change attribute is defined as a server-specific one,
	change attributes fetched from one server are normally presumed to		change attributes fetched from one server are normally presumed to
	be invalid on another server. Such a presumption is troublesome		be invalid on another server. Such a presumption is troublesome
	since it would invalidate all cached change attributes, requiring		since it would invalidate all cached change attributes, requiring
	refetching. Even more disruptive, the absence of any assured		refetching. Even more disruptive, the absence of any assured
	continuity for the change attribute means that even if the same		continuity for the change attribute means that even if the same
	value is retrieved on refetch, no conclusions can be drawn as to whether		value is retrieved on refetch, no conclusions can be drawn as to whether
	the object in question has changed. The identical change		the object in question has changed. The identical change
	attribute could be merely an artifact of a modified file with		attribute could be merely an artifact of a modified file with
	a different change attribute construction algorithm, with that		a different change attribute construction algorithm, with that
	new algorithm just happening to result in an identical change		new algorithm just happening to result in an identical change
	value.		value.
	</t>		</t>
	<t>		<t>
	When the two file systems have consistent change attribute formats,		When the two file systems have consistent change attribute formats,
	and this fact is communicated to the client by reporting		and this fact is communicated to the client by reporting
	in the same change class, the		in the same change class, the
	client may assume a continuity of change attribute construction		client may assume a continuity of change attribute construction
	and handle this situation just as it would be handled without		and handle this situation just as it would be handled without
	any file system transition.		any file system transition.
	</t>		</t>
	</section>		</section>
	<section anchor="SEC11-EFF-wv"		<section anchor="SEC11-EFF-wv" numbered="true" toc="default">
	title="Write Verifiers and File System Transitions">		<name>Write Verifiers and File System Transitions</name>
	<t>		<t>
	In a file system transition, the two file systems might be		In a file system transition, the two file systems might be
	cooperating in the handling of unstably written data.		cooperating in the handling of unstably written data.
	Clients can determine if this is the		Clients can determine if this is the
	case, by seeing if the two file systems belong to the same		case by seeing if the two file systems belong to the same
	write-verifier class. When this is the case, write		write-verifier class. When this is the case, write
	verifiers returned		verifiers returned
	from one system may be compared to those returned by the		from one system may be compared to those returned by the
	other and superfluous		other and superfluous writes can be avoided.
	writes avoided.		</t>
	</t>		<t>
	<t>
	When two file systems belong to different		When two file systems belong to different
	write-verifier classes, any verifier		write-verifier classes, any verifier
	generated by one must not be compared to one provided by the		generated by one must not be compared to one provided by the
	other. Instead, the two verifiers should be treated as not		other. Instead, the two verifiers should be treated as not
	equal even when		equal even when the values are identical.
	the values are identical.		</t>
	</t>		</section>
	</section>		<section anchor="SEC11-EFF-rdc" numbered="true" toc="default">
	<section anchor="SEC11-EFF-rdc"		<name>READDIR Cookies and Verifiers and File System Transitions</name>
	title="Readdir Cookies and Verifiers and File System Transitions">		<t>
	<t>
	In a file system transition, the two file systems might be		In a file system transition, the two file systems might be
	consistent in their handling of READDIR cookies and verifiers.		consistent in their handling of READDIR cookies and verifiers.
	Clients can determine if this is the		Clients can determine if this is the
	case, by seeing if the two file systems belong to the same		case by seeing if the two file systems belong to the same
	readdir class. When this is the		readdir class. When this is the case, readdir class, READDIR
	case, readdir class, READDIR		cookies, and verifiers
	cookies and verifiers		from one system will be recognized by the other, and
	from one system will be recognized by the other and		READDIR operations started on one server can be validly
	READDIR operations started on one server can be validly		continued on the other simply by presenting the
	continued on the other, simply by presenting the
	cookie and verifier returned by a READDIR operation done		cookie and verifier returned by a READDIR operation done
	on the first file system to the second.		on the first file system to the second.
	</t>		</t>
	<t>		<t>
	When two file systems belong to different		When two file systems belong to different
	readdir classes, any READDIR		readdir classes, any READDIR cookie and verifier
	cookie and verifier		generated by one is not valid on the second and must not
	generated by one is not valid on the second, and must not
	be presented to that server by the client. The client		be presented to that server by the client. The client
	should act as if the verifier were rejected.		should act as if the verifier were rejected.
	</t>		</t>
	</section>		</section>
	<section anchor="SEC11-EFF-data"		<section anchor="SEC11-EFF-data" numbered="true" toc="default">
	title="File System Data and File System Transitions">		<name>File System Data and File System Transitions</name>
	<t>		<t>
	When multiple replicas exist and are used simultaneously or in		When multiple replicas exist and are used simultaneously or in
	succession by a client, applications using them will		succession by a client, applications using them will normally expect
	normally expect		that they contain either the same data or data that is consistent with
	that they contain either the same data or data that is
	consistent with
	the normal sorts of changes that are made by other clients		the normal sorts of changes that are made by other clients
	updating the data of the file system		updating the data of the file system
	(with metadata being the same to the degree indicated by the		(with metadata being the same to the degree indicated by the
	fs_locations_info attribute). However, when		fs_locations_info attribute). However, when multiple file systems are
	multiple file systems are
	presented as replicas of one another, the precise relationship		presented as replicas of one another, the precise relationship
	between the data of one and the data of another is not, as a		between the data of one and the data of another is not, as a
	general matter, specified by the NFSv4.1 protocol. It is quite		general matter, specified by the NFSv4.1 protocol. It is quite
	possible to present as replicas file systems where the data of		possible to present as replicas file systems where the data of
	those file systems is sufficiently different that some applications		those file systems is sufficiently different that some applications
	have problems dealing with the transition between replicas. The		have problems dealing with the transition between replicas. The
	namespace will typically be constructed so that applications can		namespace will typically be constructed so that applications can
	choose an appropriate level of support, so that in one position in		choose an appropriate level of support, so that in one position in
	the namespace a varied set of replicas might be listed, while in		the namespace, a varied set of replicas might be listed, while in
	another only those that are up-to-date would be considered replicas.		another, only those that are up-to-date would be considered replicas.
	The protocol does define three special cases		The protocol does define three special cases of the relationship among
	of the relationship among
	replicas to be specified by the server and relied upon by clients:		replicas to be specified by the server and relied upon by clients:
			</t>
	<list style='symbols'>		<ul spacing="normal">
	<t>		<li>
	When multiple replicas exist and are used simultaneously		When multiple replicas exist and are used simultaneously
	by a client (see the FSLIB4_CLSIMUL definition within		by a client (see the FSLIB4_CLSIMUL definition within
	fs_locations_info), they must designate the same		fs_locations_info), they must designate the same
	data. Where file systems are writable, a change made on		data. Where file systems are writable, a change made on
	one instance must be visible on all instances at the same		one instance must be visible on all instances at the same
	time, regardless of whether the interrogated instance is the		time, regardless of whether the interrogated instance is the
	one on which the modification was done.		one on which the modification was done.
	This allows a client to use these replicas		This allows a client to use these replicas
	simultaneously without any special adaptation to the fact		simultaneously without any special adaptation to the fact
	that there are multiple replicas, beyond adapting to the fact		that there are multiple replicas, beyond adapting to the fact
	that locks obtained on one replica are maintained separately		that locks obtained on one replica are maintained separately
	(i.e. under a different client ID).		(i.e., under a different client ID).
	In this case, locks (whether share reservations or		In this case, locks (whether share reservations or
	byte-range locks) and delegations obtained on one		byte-range locks) and delegations obtained on one
	replica are immediately reflected on all replicas, in the		replica are immediately reflected on all replicas, in the
	sense that access from all other servers is prevented		sense that access from all other servers is prevented
	regardless of		regardless of the replica used. However, because the servers are
	the replica used. However, because the servers are		not required to treat two associated client IDs as
	not required
	to treat two associated client IDs as
	representing the same client, it is best to		representing the same client, it is best to
	access each file using		access each file using only a single client ID.
	only a single client ID.		</li>
	</t>		<li>
	<t>		When one replica is designated as the successor instance to another
	When one replica is designated as the		existing instance after the return of NFS4ERR_MOVED (i.e., the case of
	successor instance to another
	existing instance after return NFS4ERR_MOVED
	(i.e., the case of
	migration), the client may depend on the fact that all changes		migration), the client may depend on the fact that all changes
	written to stable storage on the original instance		written to stable storage on the original instance
	are written to stable storage of the successor (uncommitted		are written to stable storage of the successor (uncommitted
	writes are dealt with in		writes are dealt with in <xref target="SEC11-EFF-wv" format="default"/
	<xref target="SEC11-EFF-wv" /> above).		> above).
	</t>		</li>
	<t>		<li>
	Where a file system is not writable but represents a read-only		Where a file system is not writable but represents a read-only
	copy (possibly periodically updated) of a writable file system,		copy (possibly periodically updated) of a writable file system,
	clients have similar requirements with regard		clients have similar requirements with regard to the propagation
	to the propagation		of updates. They may need a guarantee that any change visible on
	of updates. They may need a guarantee that		the original file system instance must be immediately visible on
	any change visible on		any replica before the client transitions access to that replica,
	the original file system instance must		in order to avoid any possibility that a client, in effecting a transi
	be immediately visible on		tion to a
	any replica before the client
	transitions access to that replica,
	in order to
	avoid any possibility that a client,
	in effecting a transition to a
	replica, will see any reversion in file system state.		replica, will see any reversion in file system state.
	The specific		The specific means of this guarantee varies based on the value of
	means of this guarantee varies based on the value of		the fss_type field that is reported as part of the fs_status attribute
	the fss_type field that is		(see <xref target="fs_status" format="default"/>).
	reported as part of the fs_status attribute		Since these file systems are presumed to be unsuitable for simultaneou
	(see <xref target="fs_status" />).		s use,
	Since these file systems are presumed		there is no specification of how locking is handled; in general, locks
	to be unsuitable for simultaneous use,		obtained on one file
	there is no specification of how
	locking is handled; in general, locks obtained on one file
	system will be separate from those on others.		system will be separate from those on others.
	Since these are expected to be read-only file systems,		Since these are expected to be read-only file systems,
	this is not		this is not likely to pose an issue for clients or applications.
	likely to pose an issue for clients or applications.		</li>
	</t>		</ul>
	</list>		<t>
	</t>		When none of these special situations applies, there is no basis
	<t>
	When none of these special situations apply, there is no basis,
	within the protocol for the client to make assumptions about the		within the protocol for the client to make assumptions about the
	contents of a replica file system or its relationship to previous		contents of a replica file system or its relationship to previous
	file system instances. Thus switching between nominally		file system instances. Thus, switching between nominally
	identical read-write file		identical read-write file systems would not be possible because either the
	systems would not be possible, because either the		client does not use the fs_locations_info attribute, or the server does no
	client does not use or the server does not support the fs_locations_info		t support it.
	attribute.		</t>
	</t>		</section>
	</section>		<section anchor="SEC11-EFF-lock" numbered="true" toc="default">
	<section title="Lock State and File System Transitions"		<name>Lock State and File System Transitions</name>
	anchor="SEC11-EFF-lock">		<t>
	<t>
	While accessing a file system, clients obtain locks enforced		While accessing a file system, clients obtain locks enforced
	by the server which may prevent actions by other clients		by the server, which may prevent actions by other clients
	that are inconsistent with those locks.		that are inconsistent with those locks.
	</t>		</t>
	<t>		<t>
	When access is transferred between replicas, clients need to		When access is transferred between replicas, clients need to
	be assured that the actions disallowed by holding these locks		be assured that the actions disallowed by holding these locks
	cannot have occurred during the transition. This can be ensured		cannot have occurred during the transition. This can be ensured
	by the methods below. Unless at least one of these is implemented,		by the methods below. Unless at least one of these is implemented,
	clients will not be assured of continuity of lock		clients will not be assured of continuity of lock
	possession across a migration event.		possession across a migration event:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	Providing the client an opportunity to re-obtain his		<li>
	locks via a per-fs grace		<t>
			Providing the client an opportunity to re-obtain his locks via a per-fs
			grace
	period on the destination server, denying all clients using the		period on the destination server, denying all clients using the
	destination file system the		destination file system the
	opportunity to obtain new locks that conflict which those held		opportunity to obtain new locks that conflict with those held
	by the transferred client as long as that client		by the transferred client as long as that client
	has not completed its per-fs grace period. Because the lock reclaim		has not completed its per-fs grace period. Because the lock reclaim
	mechanism was originally defined to support server reboot, it		mechanism was originally defined to support server reboot, it
	implicitly assumes that file handles will, upon reclaim, will		implicitly assumes that filehandles will, upon reclaim,
	be the same as those at open. In the case of migration, this		be the same as those at open. In the case of migration, this
	requires that source and destination servers use the same		requires that source and destination servers use the same
	filehandles, as evidenced by using the same server scope		filehandles, as evidenced by using the same server scope
	(see <xref target="Server_Scope"/>)		(see <xref target="Server_Scope" format="default"/>)
	or by showing this		or by showing this agreement using fs_locations_info
	agreement using fs_locations_info		(see <xref target="SEC11-EFF-fh" format="default"/> above).
	(see <xref target="SEC11-EFF-fh"/> above).		</t>
	<vspace blankLines="1"/>		<t>
	Note that such a grace period can be implemented without		Note that such a grace period can be implemented without
	interfering with the ability of non-transferred clients to		interfering with the ability of non-transferred clients to
	obtain new locks while it is going on. As long as the destination		obtain new locks while it is going on. As long as the destination
	server is aware of the transferred locks, it can distinguish requests		server is aware of the transferred locks, it can distinguish requests
	to obtain new locks that contrast with existing locks		to obtain new locks that contrast with existing locks
	from those that do not, allowing it to treat such client requests		from those that do not, allowing it to treat such client requests
	without reference to the ongoing grace period.		without reference to the ongoing grace period.
	</t>		</t>
	<t>		</li>
			<li>
	Locking state can be transferred as part of the transition		Locking state can be transferred as part of the transition
	by providing Transparent State Migration as		by providing Transparent State Migration as
	described in <xref target="SEC11-trans-locking"/>.		described in <xref target="SEC11-trans-locking" format="default"/>.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Of these, Transparent State Migration provides the smoother		Of these, Transparent State Migration provides the smoother
	experience for clients in that there is no need to go through a		experience for clients in that there is no need to go through a
	reclaim process		reclaim process before new locks can be obtained; however, it requires
	before new locks can be obtained. However, it requires		a greater degree of inter-server coordination. In general, the
	a greater degree of inter-server co-ordination. In general, the
	servers taking part in migration are free to provide either		servers taking part in migration are free to provide either
	facility. However, when the filehandles can differ across the		facility. However, when the filehandles can differ across the
	migration event, Transparent State Migration is the only		migration event, Transparent State Migration is the only
	available means of providing the needed functionality.		available means of providing the needed functionality.
	</t>		</t>
	<t>		<t>
	It should be noted that these two methods are not mutually		It should be noted that these two methods are not mutually
	exclusive and that a server might well provide both. In		exclusive and that a server might well provide both. In
	particular, if there is some circumstance preventing a		particular, if there is some circumstance preventing a
	specific lock		specific lock from being transferred transparently,
	from being transferred transparently,		the destination server can allow it to be reclaimed by
	the destination server can allow it to be reclaimed, by		implementing a per-fs grace period for the migrated file system.
	implementing a		</t>
	per-fs grace period for the migrated file system.		<section anchor="SEC11-EFF-lock-sc" numbered="true" toc="default">
	</t>		<name>Security Consideration Related to Reclaiming Lock State after
			File System Transitions</name>
	<section title="Security Consideration Related to Reclaiming Lock State af		<t>
	ter File System Transitions"
	anchor="SEC11-EFF-lock-sc">
	<t>
	Although it is possible for a client reclaiming state to misrepresent		Although it is possible for a client reclaiming state to misrepresent
	its state, in the same fashion as described in		its state in the same fashion as described in
	<xref target="reclaim_security_considerations"/>, most		<xref target="reclaim_security_considerations" format="default"/>, most
	implementations providing for such reclamation in the case of		implementations providing for such reclamation in the case of
	file system transitions		file system transitions
	will have the ability to detect such misrepresentations. This limits		will have the ability to detect such misrepresentations. This limits
	the ability of unauthenticated clients to execute denial-of-service		the ability of unauthenticated clients to execute denial-of-service
	attacks in these circumstances. Nevertheless, the rules stated in		attacks in these circumstances. Nevertheless, the rules stated in
	<xref target="reclaim_security_considerations"/>, regarding principal		<xref target="reclaim_security_considerations" format="default"/> regar
	verification for reclaim requests, apply in this situation as well.		ding principal
	</t>		verification for reclaim requests apply in this situation as well.
	<t>		</t>
			<t>
	Typically, implementations that support file system transitions		Typically, implementations that support file system transitions
	will have		will have extensive information about the locks
	extensive information about the locks		to be transferred. This is because of the following:
	to be transferred. This is because:		</t>
	<list style="symbols">		<ul spacing="normal">
	<t>		<li>
	Since failure is not involved, there is no need store to locking		Since failure is not involved, there is no need to store locking
	information in persistent storage.		information in persistent storage.
	</t>		</li>
	<t>		<li>
	There is no need, as there is in the failure case, to update		There is no need, as there is in the failure case, to update
	multiple repositories containing locking state to keep them in		multiple repositories containing locking state to keep them in
	sync. Instead, there is a one-time communication of locking		sync. Instead, there is a one-time communication of locking
	state from the source to the destination server.		state from the source to the destination server.
	</t>		</li>
	<t>		<li>
	Providing this information avoids potential interference with		Providing this information avoids potential interference with
	existing clients using the destination file system, by denying		existing clients using the destination file system by denying
	them the ability to obtain new locks during the grace period.		them the ability to obtain new locks during the grace period.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	When such detailed locking information, not necessarily including		When such detailed locking information, not necessarily including
	the associated stateids, is available:		the associated stateids, is available:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	It is possible to detect reclaim requests that attempt to		It is possible to detect reclaim requests that attempt to
	reclaim locks that did not exist before the transfer, rejecting		reclaim locks that did not exist before the transfer, rejecting
	them with NFS4ERR_RECLAIM_BAD (<xref target="err_RECLAIM_BAD"/>).		them with NFS4ERR_RECLAIM_BAD (<xref target="err_RECLAIM_BAD" format=
	</t>		"default"/>).
	<t>		</li>
			<li>
	It is possible when dealing with non-reclaim requests, to determine		It is possible when dealing with non-reclaim requests, to determine
	whether they conflict with existing locks, eliminating the need		whether they conflict with existing locks, eliminating the need
	to return NFS4ERR_GRACE ((<xref target="err_GRACE"/>) on		to return NFS4ERR_GRACE (<xref target="err_GRACE" format="default"/>) on
	non-reclaim requests.		non-reclaim requests.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	It is possible for implementations of grace periods in connection		It is possible for implementations of grace periods in connection
	with file system transitions not to have detailed locking		with file system transitions not to have detailed locking
	information available at the destination server, in which case		information available at the destination server, in which case,
	the security situation is exactly as described in		the security situation is exactly as described in
	<xref target="reclaim_security_considerations"/>.		<xref target="reclaim_security_considerations" format="default"/>.
	</t>		</t>
	</section>		</section>
	<section anchor="transferred_lease"		<section anchor="transferred_lease" numbered="true" toc="default">
	title="Leases and File System Transitions">		<name>Leases and File System Transitions</name>
	<t>		<t>
	In the case of lease renewal, the client may not be		In the case of lease renewal, the client may not be
	submitting requests for a file system that has been transferred		submitting requests for a file system that has been transferred
	to another server. This can occur		to another server. This can occur
	because of the lease renewal mechanism. The		because of the lease renewal mechanism. The
	client renews the lease associated with all file systems		client renews the lease associated with all file systems
	when submitting		when submitting
	a request on an associated session, regardless of the		a request on an associated session, regardless of the
	specific file system being referenced.		specific file system being referenced.
	</t>		</t>
	<t>		<t>
	In order for the client to schedule renewal of its lease		In order for the client to schedule renewal of its lease
	where there is locking state that may have been relocated		where there is locking state that may have been relocated
	to the new server, the client		to the new server, the client
	must find out about lease relocation before that lease		must find out about lease relocation before that lease
	expire. To accomplish this, the SEQUENCE operation will		expire. To accomplish this, the SEQUENCE operation will
	return the status bit SEQ4_STATUS_LEASE_MOVED		return the status bit SEQ4_STATUS_LEASE_MOVED
	if responsibility for any of the renewed locking state		if responsibility for any of the renewed locking state
	has been transferred to a new server. This		has been transferred to a new server. This
	will continue until the client receives an		will continue until the client receives an
	NFS4ERR_MOVED error for each of the file systems for which		NFS4ERR_MOVED error for each of the file systems for which
	there has been locking state relocation.		there has been locking state relocation.
	</t>		</t>
	<t>		<t>
	When a client receives an SEQ4_STATUS_LEASE_MOVED indication from		When a client receives an SEQ4_STATUS_LEASE_MOVED indication from
	a server, for each file system of the server for which the client		a server, for each file system of the server for which the client
	has locking state, the client should perform an operation.		has locking state, the client should perform an operation.
	For simplicity, the client may choose to reference		For simplicity, the client may choose to reference
	all file systems, but what is important		all file systems, but what is important
	is that it must reference all file systems for which there was		is that it must reference all file systems for which there was
	locking state where that state has moved. Once the client		locking state where that state has moved. Once the client
	receives an NFS4ERR_MOVED error for each such file system,		receives an NFS4ERR_MOVED error for each such file system,
	the server will clear the SEQ4_STATUS_LEASE_MOVED indication.		the server will clear the SEQ4_STATUS_LEASE_MOVED indication.
	The client can terminate the process of checking file systems		The client can terminate the process of checking file systems
	once this indication is cleared (but only if the client		once this indication is cleared (but only if the client
	has received a reply for all outstanding SEQUENCE requests		has received a reply for all outstanding SEQUENCE requests
	on all sessions it has with the server), since there are no others		on all sessions it has with the server), since there are no others
	for which locking state has moved.		for which locking state has moved.
	</t>		</t>
	<t>		<t>
	A client may use GETATTR of the fs_status		A client may use GETATTR of the fs_status
	(or fs_locations_info) attribute on all of the file systems		(or fs_locations_info) attribute on all of the file systems
	to get absence indications in a single (or a few) request(s),		to get absence indications in a single (or a few) request(s),
	since absent file systems will not cause an error in this		since absent file systems will not cause an error in this
	context. However, it still must do an operation that		context. However, it still must do an operation that
	receives NFS4ERR_MOVED on each file system, in order to clear		receives NFS4ERR_MOVED on each file system, in order to clear
	the SEQ4_STATUS_LEASE_MOVED indication.		the SEQ4_STATUS_LEASE_MOVED indication.
	</t>		</t>
	<t>		<t>
	Once the set of file systems with transferred locking state		Once the set of file systems with transferred locking state
	has been determined, the client can follow the normal process		has been determined, the client can follow the normal process
	to obtain the new server information (through the		to obtain the new server information (through the
	fs_locations and fs_locations_info attributes) and perform renewal		fs_locations and fs_locations_info attributes) and perform renewal
	of that lease on the new server, unless information in the		of that lease on the new server, unless information in the
	fs_locations_info attribute shows that no state could have		fs_locations_info attribute shows that no state could have
	been transferred. If the server has not		been transferred. If the server has not
	had state transferred to it transparently, the client		had state transferred to it transparently, the client
	will receive NFS4ERR_STALE_CLIENTID		will receive NFS4ERR_STALE_CLIENTID
	from the new server,		from the new server,
	as described above, and the client can then reclaim		as described above, and the client can then reclaim
	locks		locks
	as is done in the event of server failure.		as is done in the event of server failure.
	</t>		</t>
	</section>		</section>
	<section anchor="transition_lease_time"		<section anchor="transition_lease_time" numbered="true" toc="default">
	title="Transitions and the Lease_time Attribute">		<name>Transitions and the Lease_time Attribute</name>
	<t>		<t>
	In order that the client may appropriately manage its lease		In order that the client may appropriately manage its lease
	in the case of a file system transition, the destination server must		in the case of a file system transition, the destination server must
	establish proper values for the lease_time attribute.		establish proper values for the lease_time attribute.
	</t>		</t>
	<t>		<t>
	When state is transferred transparently, that state		When state is transferred transparently, that state
	should include the correct value of the lease_time		should include the correct value of the lease_time
	attribute. The lease_time attribute on the destination		attribute. The lease_time attribute on the destination
	server must never be less than that on the source, since		server must never be less than that on the source, since
	this would result in premature expiration of a lease		this would result in premature expiration of a lease
	granted by the source server. Upon transitions in which		granted by the source server. Upon transitions in which
	state is transferred transparently, the client is under		state is transferred transparently, the client is under
	no obligation to refetch the lease_time attribute and		no obligation to refetch the lease_time attribute and
	may continue to use the value		may continue to use the value
	previously fetched (on the source server).		previously fetched (on the source server).
	</t>		</t>
	<t>		<t>
	If state has not been transferred transparently, either		If state has not been transferred transparently, either
	because the associated servers are shown as having different		because the associated servers are shown as having different
	eir_server_scope strings or because the client ID		eir_server_scope strings or because the client ID
	is rejected when presented to the new server,		is rejected when presented to the new server,
	the client should fetch the value		the client should fetch the value
	of lease_time on the new (i.e., destination) server, and		of lease_time on the new (i.e., destination) server, and
	use it for subsequent locking requests. However, the server		use it for subsequent locking requests. However, the server
	must respect a grace		must respect a grace
	period of at least as long as the lease_time on the source		period of at least as long as the lease_time on the source
	server, in order to ensure that clients have ample time to		server, in order to ensure that clients have ample time to
	reclaim their lock before potentially conflicting		reclaim their lock before potentially conflicting
	non-reclaimed locks are granted.		non-reclaimed locks are granted.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	</section>		</section>
	<section title="Transferring State upon Migration"		<section anchor="SEC11-trans-locking" numbered="true" toc="default">
	anchor="SEC11-trans-locking">		<name>Transferring State upon Migration</name>
	<t>		<t>
	When the transition is a result of a server-initiated decision		When the transition is a result of a server-initiated decision
	to transition access and the source and destination servers have		to transition access, and the source and destination servers have
	implemented appropriate co-operation, it is possible to:		implemented appropriate cooperation, it is possible to do the following:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Transfer locking state from the source to the destination		Transfer locking state from the source to the destination
	server, in a fashion similar to that provided by Transparent State		server in a fashion similar to that provided by Transparent State
	Migration in NFSv4.0, as described in <xref target="RFC7931"/>.		Migration in NFSv4.0, as described in <xref target="RFC7931" format="def
	Server responsibilities are described in		ault"/>.
	<xref target="SEC11-XS-lock"/>.		Server responsibilities are described in <xref target="SEC11-XS-lock" fo
			rmat="default"/>.
	</t>		</li>
	<t>		<li>
	Transfer session state from the source to the destination		Transfer session state from the source to the destination
	server. Server responsibilities in effecting such a		server. Server responsibilities in effecting such a
	transfer are described in		transfer are described in <xref target="SEC11-XS-session" format="defaul
	<xref target="SEC11-XS-session"/>.		t"/>.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The means by which the client determines which of these transfer		The means by which the client determines which of these transfer
	events has occurred are described in		events has occurred are described in
	<xref target="SEC11-trans-client"/>.		<xref target="SEC11-trans-client" format="default"/>.
	</t>		</t>
	<section title="Transparent State Migration and pNFS"		<section anchor="V41p-pnfs" numbered="true" toc="default">
	anchor="V41p-pnfs">		<name>Transparent State Migration and pNFS</name>
	<t>		<t>
	When pNFS is involved, the protocol is capable of supporting:		When pNFS is involved, the protocol is capable of supporting:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	Migration of the Metadata Server (MDS), leaving the Data		Migration of the Metadata Server (MDS), leaving the Data
	Servers (DS's) in place.		Servers (DSs) in place.
	</t>		</li>
	<t>		<li>
	Migration of the file system as a whole, including the MDS		Migration of the file system as a whole, including the MDS
	and associated DS's.		and associated DSs.
	</t>		</li>
	<t>		<li>
	Replacement of one DS by another.		Replacement of one DS by another.
	</t>		</li>
	<t>		<li>
	Migration of a pNFS file system to one in which		Migration of a pNFS file system to one in which pNFS is not used.
	pNFS is not used.		</li>
	</t>		<li>
	<t>
	Migration of a file system not using pNFS to one in which		Migration of a file system not using pNFS to one in which
	layouts are available.		layouts are available.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		Note that migration, per se, is only involved in the transfer of
	Note that migration per se is only involved in the transfer of		the MDS function. Although the servicing of a layout may be
	the MDS function. Although the servicing of a layout may be
	transferred from one data server to another, this not done using		transferred from one data server to another, this not done using
	the file system location attributes. The MDS can effect such		the file system location attributes. The MDS can effect such
	transfers by recalling/revoking existing layouts and granting new		transfers by recalling or revoking existing layouts and granting new
	ones on a different data server.		ones on a different data server.
	</t>		</t>
	<t>		<t>
	Migration of the MDS function is directly supported by		Migration of the MDS function is directly supported by
	Transparent State Migration. Layout state will normally be		Transparent State Migration. Layout state will normally be
	transparently transferred, just as other state is.		transparently transferred, just as other state is.
	As a result, Transparent State Migration provides a framework in		As a result, Transparent State Migration provides a framework in
	which, given appropriate inter-MDS data transfer, one MDS can		which, given appropriate inter-MDS data transfer, one MDS can
	be substituted for another.		be substituted for another.
	</t>		</t>
	<t>		<t>
	Migration of the file system function as a whole		Migration of the file system function as a whole can be accomplished by
	can be accomplished by
	recalling all layouts as part of the initial phase of the		recalling all layouts as part of the initial phase of the
	migration process. As a result, IO will be done through the		migration process. As a result, I/O will be done through the
	MDS during the migration process, and new layouts can be granted		MDS during the migration process, and new layouts can be granted
	once the client is interacting with the new MDS. An MDS can		once the client is interacting with the new MDS. An MDS can
	also effect this sort of transition by revoking all layouts		also effect this sort of transition by revoking all layouts
	as part of Transparent State Migration, as long as the client is		as part of Transparent State Migration, as long as the client is
	notified about the loss of locking state.		notified about the loss of locking state.
	</t>		</t>
	<t>		<t>
	In order to allow migration to a file system on which pNFS is		In order to allow migration to a file system on which pNFS is
	not supported, clients need to be prepared for a situation in		not supported, clients need to be prepared for a situation in
	which layouts are not available or		which layouts are not available or supported on the destination file
	supported on the destination file		system and so direct I/O requests to the destination
	system and so direct IO requests to the destination
	server, rather than depending on layouts being available.		server, rather than depending on layouts being available.
	</t>		</t>
	<t>		<t>
	Replacement of one DS by another is not addressed by migration as		Replacement of one DS by another is not addressed by migration as
	such but can be effected by an MDS recalling layouts for the DS		such but can be effected by an MDS recalling layouts for the DS
	to be replaced and issuing new ones to be served by the		to be replaced and issuing new ones to be served by the
	successor DS.		successor DS.
	</t>		</t>
	<t>		<t>
	Migration may transfer a file system from a server which does		Migration may transfer a file system from a server that does
	not support pNFS to one which does. In order to properly adapt		not support pNFS to one that does. In order to properly adapt
	to this situation, clients which support pNFS, but function		to this situation, clients that support pNFS, but function
	adequately in its absence should check for pNFS support when		adequately in its absence, should check for pNFS support when
	a file system is migrated and be prepared to use pNFS when		a file system is migrated and be prepared to use pNFS when
	support is available on the destination.		support is available on the destination.
	</t>		</t>
	</section>		</section>
			</section>
	</section>		<section anchor="SEC11-trans-client" numbered="true" toc="default">
	<section title="Client Responsibilities when Access is Transitioned"		<name>Client Responsibilities When Access Is Transitioned</name>
	anchor="SEC11-trans-client">		<t>
	<t>
	For a client to respond to an access transition, it must become		For a client to respond to an access transition, it must become
	aware of it. The ways in which this can happen are discussed		aware of it. The ways in which this can happen are discussed
	in <xref target="V41c-clrecov"/> which discusses indications		in <xref target="V41c-clrecov" format="default"/>, which discusses indicat ions
	that a specific file system access path has transitioned as well as		that a specific file system access path has transitioned as well as
	situations in which additional activity is necessary to		situations in which additional activity is necessary to
	determine the set of file systems that have been migrated.		determine the set of file systems that have been migrated.
	<xref target="V41c-migrdisc"/> goes on to complete the discussion		<xref target="V41c-migrdisc" format="default"/> goes on to complete the di scussion
	of how the set of migrated file systems might be determined.		of how the set of migrated file systems might be determined.
	Sections <xref target="V41c-omoved" format="counter"/> through		Sections <xref target="V41c-omoved" format="counter"/> through
	<xref target="V41c-ssnwas" format="counter"/>		<xref target="V41c-ssnwas" format="counter"/>
	discuss how the client should deal with		discuss how the client should deal with
	each transition it becomes aware of, either directly or as a		each transition it becomes aware of, either directly or as a
	result of migration discovery.		result of migration discovery.
	</t>		</t>
	<t>		<t>
	The following terms are used to describe client activities:		The following terms are used to describe client activities:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	"Transition recovery" refers to the process of restoring access		"Transition recovery" refers to the process of restoring access
	to a file system on which NFS4ERR_MOVED was received.		to a file system on which NFS4ERR_MOVED was received.
	</t>		</li>
	<t>		<li>
	"Migration recovery" to that subset of transition recovery		"Migration recovery" refers to that subset of transition recovery
	which applies when the file system has migrated to a different		that applies when the file system has migrated to a different
	replica.		replica.
	</t>		</li>
	<t>		<li>
	"Migration discovery" refers to the process of determining which		"Migration discovery" refers to the process of determining which
	file system(s) have been migrated. It is necessary to		file system(s) have been migrated. It is necessary to avoid a situation
	avoid a situation in		in
	which leases could expire when a file system is not accessed for		which leases could expire when a file system is not accessed for
	a long period of time, since a client unaware of the migration		a long period of time, since a client unaware of the migration
	might be referencing an unmigrated file system and not renewing		might be referencing an unmigrated file system and not renewing
	the lease associated with the migrated file system.		the lease associated with the migrated file system.
	</t>		</li>
	</list>		</ul>
	</t>		<section anchor="V41c-clrecov" numbered="true" toc="default">
	<section title="Client Transition Notifications"		<name>Client Transition Notifications</name>
	anchor="V41c-clrecov">		<t>
	<t>
	When there is a change in the network access		When there is a change in the network access
	path which a client is to use to access a file		path that a client is to use to access a file system, there
	system, there		are a number of related status indications with which clients
	are a number of
	related status indications with which clients
	need to deal:		need to deal:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	If an attempt is made to use or return a filehandle		If an attempt is made to use or return a filehandle
	within a file system that is no longer accessible at the		within a file system that is no longer accessible at the
	address previously used to access it, the		address previously used to access it, the
	error NFS4ERR_MOVED is returned.		error NFS4ERR_MOVED is returned.
	<vspace blankLines='1' />		</t>
	Exceptions are made to allow such file handles to be used		<t>
			Exceptions are made to allow such filehandles to be used
	when interrogating a file system location attribute.		when interrogating a file system location attribute.
	This enables a		This enables a client to determine
	client to determine
	a new replica's location or a new network access path.		a new replica's location or a new network access path.
	<vspace blankLines='1' />		</t>
			<t>
	This condition continues on subsequent attempts to access		This condition continues on subsequent attempts to access
	the file system in question. The only way the client		the file system in question. The only way the client
	can avoid the error is to cease accessing the file system in		can avoid the error is to cease accessing the file system in
	question at its old server location and access it instead		question at its old server location and access it instead
	using a different address at which it is now available.		using a different address at which it is now available.
	</t>		</t>
	<t>		</li>
	Whenever a SEQUENCE operation is sent by a client to		<li>
	a server which generated state held on that client which		<t>
	is associated with a file system that is no longer accessible		Whenever a client sends a SEQUENCE operation to a server that
	on the server at which it was previously available, the response		generated state held on that client and associated with a
	will contain a		file system no longer accessible on that server, the response will contain
	lease-migrated indication, with the		the status bit SEQ4_STATUS_LEASE_MOVED, indicating that there has
	SEQ4_STATUS_LEASE_MOVED status bit being set.		been a lease migration.
	<vspace blankLines='1' />		</t>
			<t>
	This condition continues until the client acknowledges		This condition continues until the client acknowledges
	the notification by fetching a file system		the notification by fetching a file system location attribute for the
	location attribute for the
	file system whose network access path is being changed.		file system whose network access path is being changed.
	When there are multiple such file systems, a location attribute		When there are multiple such file systems, a location attribute
	for each such file system needs to be fetched. The location		for each such file system needs to be fetched. The location
	attribute for all migrated file system needs to be fetched		attribute for all migrated file systems needs to be fetched
	in order to clear the condition.		in order to clear the condition. Even after the condition is cleared,
	Even after the condition is cleared, the		the
	client needs to respond by using the location information		client needs to respond by using the location information
	to access the file system at its new location		to access the file system at its new location
	to ensure that leases are		to ensure that leases are not needlessly expired.
	not needlessly expired.		</t>
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		Unlike NFSv4.0, in which the corresponding
	Unlike the case of NFSv4.0, in which the corresponding
	conditions are both errors and thus mutually exclusive,		conditions are both errors and thus mutually exclusive,
	in NFSv4.1 the client can,		in NFSv4.1 the client can,
	and often will, receive both indications on the same		and often will, receive both indications on the same
	request. As a result, implementations need to address the		request. As a result, implementations need to address the
	question of how to co-ordinate		question of how to coordinate
	the necessary recovery actions when both indications		the necessary recovery actions when both indications
	arrive in the response to the same request. It should be noted		arrive in the response to the same request. It should be noted
	that when processing an NFSv4 COMPOUND, the server		that when processing an NFSv4 COMPOUND, the server
	will normally decide		will normally decide
	whether SEQ4_STATUS_LEASE_MOVED is to be set before		whether SEQ4_STATUS_LEASE_MOVED is to be set before
	it determines which file system will be referenced or whether		it determines which file system will be referenced or whether
	NFS4ERR_MOVED is to be returned.		NFS4ERR_MOVED is to be returned.
	</t>		</t>
	<t>		<t>
	Since these indications are not mutually exclusive in NFSv4.1,		Since these indications are not mutually exclusive in NFSv4.1,
	the following combinations are possible results when a COMPOUND		the following combinations are possible results when a COMPOUND
	is issued:		is issued:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	The COMPOUND status		The COMPOUND status
	is NFS4ERR_MOVED and SEQ4_STATUS_LEASE_MOVED is asserted.		is NFS4ERR_MOVED, and SEQ4_STATUS_LEASE_MOVED is asserted.
	<vspace blankLines='1'/>		</t>
			<t>
	In this case, transition recovery is required. While it is		In this case, transition recovery is required. While it is
	possible that migration discovery is needed in addition, it		possible that migration discovery is needed in addition, it
	is likely that only the accessed file system has transitioned.		is likely that only the accessed file system has transitioned.
	In any case, because addressing NFS4ERR_MOVED is necessary to		In any case, because addressing NFS4ERR_MOVED is necessary to
	allow the rejected requests to be processed on the target,		allow the rejected requests to be processed on the target,
	dealing with it will typically have priority over		dealing with it will typically have priority over
	migration discovery.		migration discovery.
			</t>
	</t>		</li>
	<t>		<li>
			<t>
	The COMPOUND status		The COMPOUND status
	is NFS4ERR_MOVED and SEQ4_STATUS_LEASE_MOVED is clear.		is NFS4ERR_MOVED, and SEQ4_STATUS_LEASE_MOVED is clear.
	<vspace blankLines='1'/>		</t>
			<t>
	In this case, transition recovery is also required. It is		In this case, transition recovery is also required. It is
	clear that migration discovery is not needed to find		clear that migration discovery is not needed to find
	file systems that have been migrated other that the one		file systems that have been migrated other than the one
	returning NFS4ERR_MOVED. Cases in which this		returning NFS4ERR_MOVED. Cases in which this
	result can arise include a referral or a migration for which		result can arise include a referral or a migration for which
	there is no associated locking state. This can also arise in		there is no associated locking state. This can also arise in
	cases in which an access path transition		cases in which an access path transition
	other than migration occurs within the same server. In such a		other than migration occurs within the same server. In such a
	case, there is no need to set SEQ4_STATUS_LEASE_MOVED, since		case, there is no need to set SEQ4_STATUS_LEASE_MOVED, since
	the lease remains associated with the current server even though		the lease remains associated with the current server even though
	the access path has changed.		the access path has changed.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	The COMPOUND status		The COMPOUND status
	is not NFS4ERR_MOVED and SEQ4_STATUS_LEASE_MOVED is asserted.		is not NFS4ERR_MOVED, and SEQ4_STATUS_LEASE_MOVED is asserted.
	<vspace blankLines='1'/>		</t>
			<t>
	In this case, no transition recovery activity is required on		In this case, no transition recovery activity is required on
	the file system(s) accessed by the request.		the file system(s) accessed by the request. However, to prevent avoid
	However, to prevent avoidable		able
	lease expiration, migration discovery needs to be done		lease expiration, migration discovery needs to be done.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	The COMPOUND status		The COMPOUND status
	is not NFS4ERR_MOVED and SEQ4_STATUS_LEASE_MOVED is clear.		is not NFS4ERR_MOVED, and SEQ4_STATUS_LEASE_MOVED is clear.
	<vspace blankLines='1'/>		</t>
			<t>
	In this case, neither transition-related activity nor migration		In this case, neither transition-related activity nor migration
	discovery is required.		discovery is required.
	</t>		</t>
	</list>		</li>
	</t>		</ul>
	<t>		<t>
	Note that the specified actions only need to be taken if they are		Note that the specified actions only need to be taken if they are
	not already going on. For example, when NFS4ERR_MOVED is received		not already going on. For example, when NFS4ERR_MOVED is received
	when accessing a file system		while accessing a file system for which transition recovery is already oc
	for which transition recovery already going on, the client		curring, the client
	merely waits for		merely waits for that recovery to be completed, while the receipt of
	that recovery to be completed while the receipt of		the SEQ4_STATUS_LEASE_MOVED indication only
	SEQ4_STATUS_LEASE_MOVED indication only
	needs to initiate migration discovery for a server if such		needs to initiate migration discovery for a server if such
	discovery is not already underway for that server.		discovery is not already underway for that server.
	</t>		</t>
	<t>		<t>
	The fact that a lease-migrated condition does not result in		The fact that a lease-migrated condition does not result in
	an error in NFSv4.1 has a number of important consequences.		an error in NFSv4.1 has a number of important consequences.
	In addition to the fact, discussed above, that the two		In addition to the fact that the two
	indications are not mutually exclusive, there are number of		indications are not mutually exclusive, as discussed above, there are nu
			mber of
	issues that are important in considering implementation of		issues that are important in considering implementation of
	migration discovery, as discussed in		migration discovery, as discussed in
	<xref target="V41c-migrdisc"/>.		<xref target="V41c-migrdisc" format="default"/>.
	</t>		</t>
	<t>		<t>
	Because SEQ4_STATUS_LEASE_MOVED is not an		Because SEQ4_STATUS_LEASE_MOVED is not an error condition, it is possibl
	error condition", it is possible		e
	for file systems whose access paths have not changed to be		for file systems whose access paths have not changed to be
	successfully accessed on a given server even though recovery		successfully accessed on a given server even though recovery
	is necessary for other file systems on the same server. As		is necessary for other file systems on the same server. As
	a result, access can go on while,		a result, access can take place while:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	The migration discovery process is going on for that server.		<li>
	</t>		The migration discovery process is happening for that server.
	<t>		</li>
	The transition recovery process is going on for other		<li>
			The transition recovery process is happening for other
	file systems connected to that server.		file systems connected to that server.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section anchor="V41c-migrdisc" numbered="true" toc="default">
	<section title="Performing Migration Discovery"		<name>Performing Migration Discovery</name>
	anchor="V41c-migrdisc">		<t>
	<t>
	Migration discovery can be performed in the same context as		Migration discovery can be performed in the same context as
	transition recovery, allowing recovery for each migrated file		transition recovery, allowing recovery for each migrated file
	system to be invoked as it is discovered. Alternatively, it may		system to be invoked as it is discovered. Alternatively, it may
	be done in a separate migration discovery thread, allowing		be done in a separate migration discovery thread, allowing
	migration discovery to be done in parallel with		migration discovery to be done in parallel with
	one or more instances		one or more instances of transition recovery.
	of transition recovery.		</t>
	</t>		<t>
	<t>
	In either case, because the lease-migrated indication		In either case, because the lease-migrated indication
	does not result in an error. other access to file systems on the		does not result in an error, other access to file systems on the
	server can proceed normally, with the possibility that further		server can proceed normally, with the possibility that further
	such indications will be received, raising the issue of how		such indications will be received, raising the issue of how
	such indications are to be dealt with. In general,		such indications are to be dealt with. In general:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	No action needs to be taken for such indications received by any		No action needs to be taken for such indications received by any
	threads performing migration discovery, since continuation of that		threads performing migration discovery, since continuation of that
	work will address the issue.		work will address the issue.
	</t>		</li>
	<t>		<li>
	In other cases in which migration discovery is currently		In other cases in which migration discovery is currently being perform
	being performed,		ed,
	nothing further needs to be done to respond to such lease		nothing further needs to be done to respond to such lease
	migration indications, as long as one can be		migration indications, as long as one can be certain that the migratio
	certain that the migration		n
	discovery process would deal with those indications. See below		discovery process would deal with those indications. See below for det
	for details.		ails.
	</t>		</li>
	<t>		<li>
	For such indications received in all other contexts, the		For such indications received in all other contexts, the
	appropriate response is to initiate or		appropriate response is to initiate or otherwise provide for the
	otherwise provide for the
	execution of migration discovery for file systems		execution of migration discovery for file systems
	associated with the server IP address returning the indication.		associated with the server IP address returning the indication.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	This leaves a potential difficulty in situations in which the		This leaves a potential difficulty in situations in which the
	migration discovery process is near to completion but is still		migration discovery process is near to completion but is still
	operating. One should not ignore a LEASE_MOVED indication if		operating. One should not ignore a SEQ4_STATUS_LEASE_MOVED indication i f
	the migration discovery process is not able to respond to		the migration discovery process is not able to respond to
	the discovery of additional		the discovery of additional migrating file
	migrating file
	systems without additional aid. A further complexity relevant in		systems without additional aid. A further complexity relevant in
	addressing such situations is that a lease-migrated indication may		addressing such situations is that a lease-migrated indication may
	reflect the server's state at the time the SEQUENCE operation		reflect the server's state at the time the SEQUENCE operation
	was processed, which may be different from that in effect at the		was processed, which may be different from that in effect at the
	time the response is received. Because new migration events		time the response is received. Because new migration events
	may occur		may occur at any time, and because a SEQ4_STATUS_LEASE_MOVED indication m
	at any time, and because a LEASE_MOVED indication may reflect		ay reflect
	the situation in effect a considerable time before the indication		the situation in effect a considerable time before the indication
	is received,		is received, special care needs to be taken to ensure that SEQ4_STATUS_LE
	special care needs to be taken to ensure that LEASE_MOVED		ASE_MOVED
	indications are not inappropriately ignored.		indications are not inappropriately ignored.
	</t>		</t>
	<t>		<t>
	A useful approach to this issue involves the use of separate		A useful approach to this issue involves the use of separate
	externally-visible migration discovery states for each server.		externally-visible migration discovery states for each server.
	Separate values could represent the various possible states for		Separate values could represent the various possible states for
	the migration discovery process for a server:		the migration discovery process for a server:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	non-operation, in which migration discovery is not being		<li>
	performed		Non-operation, in which migration discovery is not being
	</t>		performed.
	<t>		</li>
	normal operation, in which there is an ongoing scan for		<li>
			Normal operation, in which there is an ongoing scan for
	migrated file systems.		migrated file systems.
	</t>		</li>
	<t>		<li>
	completion/verification of migration discovery processing,		Completion/verification of migration discovery processing,
	in which the possible completion of migration discovery		in which the possible completion of migration discovery
	processing needs to be verified.		processing needs to be verified.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Given that framework, migration discovery processing would proceed		Given that framework, migration discovery processing would proceed
	as follows.		as follows:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	While in the normal-operation state, the thread performing		While in the normal-operation state, the thread performing
	discovery would fetch, for		discovery would fetch, for
	successive file systems known to the client on the server being		successive file systems known to the client on the server being
	worked on, a file system location		worked on, a file system location attribute plus the fs_status attribu
	attribute plus the fs_status attribute.		te.
	</t>		</li>
	<t>		<li>
	If the fs_status attribute indicates that the file system		If the fs_status attribute indicates that the file system
	is a migrated one (i.e. fss_absent is true and		is a migrated one (i.e., fss_absent is true, and
	fss_type != STATUS4_REFERRAL) then a migrated file system has		fss_type != STATUS4_REFERRAL), then a migrated file system has
	been found. In this situation, it is likely		been found. In this situation, it is likely
	that the fetch of the file system location attribute has		that the fetch of the file system location attribute has
	cleared one the file systems contributing to the		cleared one of the file systems contributing to the
	lease-migrated indication.		lease-migrated indication.
	</t>		</li>
	<t>		<li>
	In cases in which that happened, the thread cannot know whether		In cases in which that happened, the thread cannot know whether
	the lease-migrated indication has been cleared		the lease-migrated indication has been cleared, and so it enters the
	and so it enters the
	completion/verification state and proceeds to issue a COMPOUND		completion/verification state and proceeds to issue a COMPOUND
	to see if the LEASE_MOVED indication has been cleared.		to see if the SEQ4_STATUS_LEASE_MOVED indication has been cleared.
	</t>		</li>
	<t>		<li>
	When the discovery process is in the		When the discovery process is in the completion/verification state,
	completion/verification state,		if other requests get a lease-migrated indication,
	if other requests get a lease-migrated indication
	they note that it was received. Later, the existence of such		they note that it was received. Later, the existence of such
	indications is used when the request completes, as		indications is used when the request completes, as described below.
	described below.		</li>
	</t>		</ul>
	</list>		<t>
	</t>		When the request used in the completion/verification state completes:
	<t>		</t>
	When the request used in the completion/verification state		<ul spacing="normal">
	completes:		<li>
	<list style ='symbols'>
	<t>
	If a lease-migrated indication is returned, the discovery		If a lease-migrated indication is returned, the discovery
	continues normally. Note that this is so		continues normally. Note that this is so even if all file systems
	even if all file systems		have been traversed, since new migrations could have occurred
	have traversed, since new migrations could have occurred		while the process was going on.
	while the process		</li>
	was going on.		<li>
	</t>
	<t>
	Otherwise, if there is any record that other requests saw a		Otherwise, if there is any record that other requests saw a
	lease-migrated indication while the request was going on,		lease-migrated indication while the request was occurring,
	that record is cleared and the		that record is cleared, and the verification request is retried. The d
	verification request retried. The discovery		iscovery
	process remains in completion/verification state.		process remains in the completion/verification state.
	</t>		</li>
	<t>		<li>
	If there have been no lease-migrated indications, the work of		If there have been no lease-migrated indications, the work of
	migration discovery is considered completed and it enters the		migration discovery is considered completed, and it enters the
	non-operating state. Once it enters this state, subsequent		non-operating state. Once it enters this state, subsequent
	lease-migrated indication will trigger a new migration discovery		lease-migrated indications will trigger a new migration discovery
	process.		process.
	</t>		</li>
	</list>		</ul>
			<t>
	</t>
	<t>
	It should be noted that the process described above is not		It should be noted that the process described above is not
	guaranteed to terminate, as a long series of new migration		guaranteed to terminate, as a long series of new migration
	events might continually delay the clearing of the LEASE_MOVED		events might continually delay the clearing of the SEQ4_STATUS_LEASE_MOVE D
	indication. To prevent unnecessary lease expiration, it is		indication. To prevent unnecessary lease expiration, it is
	appropriate for clients		appropriate for clients
	to use the discovery of migrations to effect lease		to use the discovery of migrations to effect lease
	renewal immediately, rather than waiting for clearing of the		renewal immediately, rather than waiting for the clearing of the
	LEASE_MOVED indication when the complete set of migrations is		SEQ4_STATUS_LEASE_MOVED indication when the complete set of migrations is
	available.		available.
	</t>		</t>
	<t>		<t>
	Lease discovery needs to be provided as described above. This		Lease discovery needs to be provided as described above. This
	ensures that the client discovers file system migrations soon		ensures that the client discovers file system migrations soon
	enough to renew its leases on each destination server before they		enough to renew its leases on each destination server before they
	expire. Non-renewal of leases can lead to loss of locking state.		expire. Non-renewal of leases can lead to loss of locking state.
	While the consequences of such		While the consequences of such
	loss can be ameliorated through implementations of courtesy locks,		loss can be ameliorated through implementations of courtesy locks,
	servers are under no obligation to do so, and a conflicting lock request		servers are under no obligation to do so, and a conflicting lock request
	may mean that a lock is revoked unexpectedly. Clients should be aware		may mean that a lock is revoked unexpectedly. Clients should be aware
	of this possibility.		of this possibility.
	</t>		</t>
	</section>		</section>
	<section title="Overview of Client Response to NFS4ERR_MOVED"		<section anchor="V41c-omoved" numbered="true" toc="default">
	anchor="V41c-omoved">		<name>Overview of Client Response to NFS4ERR_MOVED</name>
	<t>		<t>
	This section outlines a way in which a client that receives		This section outlines a way in which a client that receives
	NFS4ERR_MOVED can effect transition recovery by using a new		NFS4ERR_MOVED can effect transition recovery by using a new
	server or server endpoint		server or server endpoint
	if one is available. As part of that process, it will		if one is available. As part of that process, it will
	determine:		determine:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	Whether the NFS4ERR_MOVED indicates migration has occurred,		Whether the NFS4ERR_MOVED indicates migration has occurred,
	or whether it indicates another sort of file system		or whether it indicates another sort of file system
	access transition as discussed		access transition as discussed
	in <xref target="SEC11-nwa"/> above.		in <xref target="SEC11-nwa" format="default"/> above.
	</t>		</li>
	<t>		<li>
	In the case of migration, whether Transparent State		In the case of migration, whether Transparent State
	Migration has occurred.		Migration has occurred.
	</t>		</li>
	<t>		<li>
	Whether any state has been lost during the process of		Whether any state has been lost during the process of
	Transparent State Migration.		Transparent State Migration.
	</t>		</li>
	<t>		<li>
	Whether sessions have been transferred as part of Transparent		Whether sessions have been transferred as part of Transparent
	State Migration.		State Migration.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	During the first phase of this process, the client proceeds to		During the first phase of this process, the client proceeds to
	examine file system location entries to find the initial		examine file system location entries to find the initial
	network address		network address
	it will use to continue access		it will use to continue access
	to the file system or its replacement.		to the file system or its replacement.
	For each location entry that the client examines, the process		For each location entry that the client examines, the process
	consists of five steps:		consists of five steps:
	<list style="numbers">		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	Performing an EXCHANGE_ID		Performing an EXCHANGE_ID
	directed at the location address. This operation is used to		directed at the location address. This operation is used to
	register the client owner (in the form of a client_owner4)		register the client owner (in the form of a client_owner4)
	with the server, to obtain a client ID		with the server, to obtain a client ID
	to be use subsequently to communicate with it, to obtain that		to be used subsequently to communicate with it, to obtain that
	client ID's confirmation status, and to determine server_owner		client ID's confirmation status, and to determine server_owner4
	and scope for the purpose of determining if the entry		and scope for the purpose of determining if the entry
	is trunkable with that		is trunkable with the address
	previously being used to access the file system (i.e. that		previously being used to access the file system (i.e., that
	it represents another network access path to the same		it represents another network access path to the same
	file system and can share		file system and can share locking state with it).
	locking state with it).		</li>
	</t>		<li>
	<t>
	Making an initial determination of whether migration has		Making an initial determination of whether migration has
	occurred. The initial determination will be based		occurred. The initial determination will be based
	on whether the EXCHANGE_ID results indicate that the		on whether the EXCHANGE_ID results indicate that the
	current location element is server-trunkable with that		current location element is server-trunkable with that
	used to access the file system when access		used to access the file system when access
	was terminated by receiving NFS4ERR_MOVED.		was terminated by receiving NFS4ERR_MOVED.
	If it is, then migration has not occurred. In that case, the		If it is, then migration has not occurred. In that case, the
	transition is		transition is
	dealt with, at least initially, as one involving continued		dealt with, at least initially, as one involving continued
	access to the same file system on the same server through		access to the same file system on the same server through
	a new network address.		a new network address.
	</t>		</li>
	<t>		<li>
	Obtaining access to existing session state or creating new		Obtaining access to existing session state or creating new
	sessions. How this is done depends on the initial		sessions. How this is done depends on the initial
	determination of whether migration has occurred and		determination of whether migration has occurred and
	can be done as described in <xref target="V41c-ssmig"/> below		can be done as described in <xref target="V41c-ssmig" format="default" /> below
	in the case of migration or as described in		in the case of migration or as described in
	<xref target="V41c-ssnwas"/> below		<xref target="V41c-ssnwas" format="default"/> below
	in the case of a network		in the case of a network address transfer without migration.
	address transfer without migration.		</li>
	</t>		<li>
	<t>		Verifying the trunking relationship assumed in step
	Verification of the trunking relationship assumed in step		2 as discussed in <xref target="PREP-trunk-verify" format="default"/>.
	2 as discussed in <xref target="PREP-trunk-verify"/>.		Although this step will generally confirm the initial
	Although this step will generally confirm the initial		determination, it is possible for verification to invalidate
	determination, it is possible for verification to fail with		the initial determination of network address shift (without
	the result that an initial determination that a network address		migration) and instead determine that migration had occurred.
	shift (without migration) has occurred may be invalidated and		There is no need to redo
	migration determined to have occurred. There is no need to redo
	step 3 above, since it will be possible to continue use of the		step 3 above, since it will be possible to continue use of the
	session established already.		session established already.
	</t>		</li>
	<t>		<li>
	Obtaining access to existing locking state and/or		Obtaining access to existing locking state and/or
	reobtaining it. How this is done depends on the final		re-obtaining it. How this is done depends on the final
	determination of whether migration has occurred and		determination of whether migration has occurred and
	can be done as described below in <xref target="V41c-ssmig"/>		can be done as described below in <xref target="V41c-ssmig" format="de fault"/>
	in the case of migration or as described in		in the case of migration or as described in
	<xref target="V41c-ssnwas"/>		<xref target="V41c-ssnwas" format="default"/>
	in the case of a network		in the case of a network address transfer without migration.
	address transfer without migration.		</li>
			</ol>
	</t>		<t>
	</list>
	</t>
	<t>
	Once the initial address has been determined, clients are free		Once the initial address has been determined, clients are free
	to apply an abbreviated process to find additional addresses		to apply an abbreviated process to find additional addresses
	trunkable with it (clients may seek session-trunkable or		trunkable with it (clients may seek session-trunkable or
	server-trunkable addresses depending on whether they support		server-trunkable addresses depending on whether they support
	clientid trunking). During this later phase of the process,		client ID trunking). During this later phase of the process,
	further location entries are examined using the abbreviated		further location entries are examined using the abbreviated
	procedure specified below:		procedure specified below:
	<list style="format %C:">		</t>
	<t>		<ol spacing="normal" type="%C:">
			<li>
	Before the EXCHANGE_ID, the fs name of the location		Before the EXCHANGE_ID, the fs name of the location
	entry is examined and if it		entry is examined, and if it
	does not match that currently being used, the entry is ignored.		does not match that currently being used, the entry is ignored.
	otherwise, one proceeds as specified by step 1 above.		Otherwise, one proceeds as specified by step 1 above.
	</t>		</li>
	<t>		<li>
	In the case that the network address is session-trunkable with one		In the case that the network address is session-trunkable with one
	used previously a BIND_CONN_TO_SESSION is used to access that		used previously, a BIND_CONN_TO_SESSION is used to access that
	session using the new network address. Otherwise, or if the bind		session using the new network address. Otherwise, or if the bind
	operation fails, a CREATE_SESSION is done.		operation fails, a CREATE_SESSION is done.
	</t>		</li>
	<t>		<li>
	The verification procedure referred to in step 4 above is		The verification procedure referred to in step 4 above is
	used. However, if it fails, the entry is ignored and the next		used. However, if it fails, the entry is ignored and the next
	available entry is used.		available entry is used.
	</t>		</li>
	</list>		</ol>
	</t>		</section>
	</section>		<section anchor="V41c-ssmig" numbered="true" toc="default">
			<name>Obtaining Access to Sessions and State after Migration</name>
	<section title="Obtaining Access to Sessions and State after Migration"		<t>
	anchor="V41c-ssmig">
	<t>
	In the event that migration has occurred, migration recovery		In the event that migration has occurred, migration recovery
	will involve determining		will involve determining whether Transparent State Migration has
	whether Transparent State Migration has
	occurred. This decision is made based on the client ID returned		occurred. This decision is made based on the client ID returned
	by the EXCHANGE_ID		by the EXCHANGE_ID and the reported confirmation status.
	and the reported		</t>
	confirmation status.		<ul spacing="normal">
	<list style ='symbols'>		<li>
	<t>
	If the client ID is an unconfirmed client ID not previously known		If the client ID is an unconfirmed client ID not previously known
	to the client, then Transparent State		to the client, then Transparent State Migration has not occurred.
	Migration has not occurred.		</li>
	</t>		<li>
	<t>
	If the client ID is a confirmed client ID previously known		If the client ID is a confirmed client ID previously known
	to the client, then any transferred state would have been		to the client, then any transferred state would have been
	merged with an existing client ID representing the client to the		merged with an existing client ID representing the client to the
	destination server. In this state merger case, Transparent		destination server. In this state merger case, Transparent
	State Migration might		State Migration might
	or might not have occurred and a determination as to whether		or might not have occurred, and a determination as to whether
	it has occurred is deferred until sessions are established		it has occurred is deferred until sessions are established
	and the client is ready to begin state recovery.		and the client is ready to begin state recovery.
	</t>		</li>
	<t>		<li>
	If the client ID is a confirmed client ID not previously known		If the client ID is a confirmed client ID not previously known
	to the client, then the client can conclude that the		to the client, then the client can conclude that the
	client ID was transferred as part of Transparent State Migration.		client ID was transferred as part of Transparent State Migration.
	In this transferred client ID case, Transparent State Migration		In this transferred client ID case, Transparent State Migration
	has occurred although some state might have been lost.		has occurred, although some state might have been lost.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Once the client ID has been obtained, it is necessary to		Once the client ID has been obtained, it is necessary to
	obtain access to sessions to continue communication with the		obtain access to sessions to continue communication with the
	new server.		new server.
	In any of the cases in which Transparent State Migration		In any of the cases in which Transparent State Migration
	has occurred, it is possible that a session was transferred		has occurred, it is possible that a session was transferred
	as well. To deal with that possibility, clients can, after		as well. To deal with that possibility, clients can, after
	doing the EXCHANGE_ID, issue a BIND_CONN_TO_SESSION to		doing the EXCHANGE_ID, issue a BIND_CONN_TO_SESSION to
	connect the transferred session to a connection to the new		connect the transferred session to a connection to the new
	server. If that fails, it is an indication that the session		server. If that fails, it is an indication that the session
	was not transferred and that a new session needs to be created to		was not transferred and that a new session needs to be created to
	take its place.		take its place.
	</t>		</t>
	<t>		<t>
	In some situations, it is possible for a BIND_CONN_TO_SESSION		In some situations, it is possible for a BIND_CONN_TO_SESSION
	to succeed without session migration having occurred. If		to succeed without session migration having occurred. If
	state merger has taken place then the associated client ID		state merger has taken place, then the associated client ID
	may have already had a set of existing sessions, with it		may have already had a set of existing sessions, with it
	being possible that the sessionid of a given session is the		being possible that the session ID of a given session is the
	same as one that might have been migrated. In that event,		same as one that might have been migrated. In that event,
	a BIND_CONN_TO_SESSION might succeed, even though there		a BIND_CONN_TO_SESSION might succeed, even though there
	could have been no migration of the session with that sessionid.		could have been no migration of the session with that session ID.
	In such cases, the client will receive sequence errors when the		In such cases, the client will receive sequence errors when the
	slot sequence values used are not appropriate on the new		slot sequence values used are not appropriate on the new
	session. When this occurs, the client can create a new a		session. When this occurs, the client can create a new a
	session and cease using the existing one.		session and cease using the existing one.
	</t>		</t>
	<t>		<t>
	Once the client has determined the initial migration status,		Once the client has determined the initial migration status,
	and determined that there was a shift to a new server, it		and determined that there was a shift to a new server, it
	needs to re-establish its locking state, if possible. To enable		needs to re-establish its locking state, if possible. To enable
	this to happen without loss of the guarantees normally provided by		this to happen without loss of the guarantees normally provided by
	locking, the destination server needs to implement a per-fs grace		locking, the destination server needs to implement a per-fs grace
	period in all cases in which lock state was lost, including		period in all cases in which lock state was lost, including
	those in which Transparent State Migration was not		those in which Transparent State Migration was not
	implemented. Each client for which there was a transfer of locking		implemented. Each client for which there was a transfer of locking
	state to the new server will have the duration of the grace period		state to the new server will have the duration of the grace period
	to reclaim its locks, from the time its locks were transferred.		to reclaim its locks, from the time its locks were transferred.
	</t>		</t>
	<t>		<t>
	Clients need to deal with the following cases:		Clients need to deal with the following cases:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	In the state merger case, it is possible that the server		In the state merger case, it is possible that the server
	has not attempted Transparent State Migration,		has not attempted Transparent State Migration,
	in which case state may have been		in which case state may have been
	lost without it being reflected in the SEQ4_STATUS bits.		lost without it being reflected in the SEQ4_STATUS bits.
	To determine whether this has happened, the client can use		To determine whether this has happened, the client can use
	TEST_STATEID to check whether the stateids created on the		TEST_STATEID to check whether the stateids created on the
	source server are still accessible on the destination server.		source server are still accessible on the destination server.
	Once a single stateid is found to have been successfully		Once a single stateid is found to have been successfully
	transferred, the client can conclude that Transparent State		transferred, the client can conclude that Transparent State
	Migration was begun and any failure to transport all of the		Migration was begun, and any failure to transport all of the
	stateids will be reflected in the SEQ4_STATUS bits. Otherwise,		stateids will be reflected in the SEQ4_STATUS bits. Otherwise,
	Transparent State Migration has not occurred.		Transparent State Migration has not occurred.
	</t>		</li>
	<t>		<li>
	In a case in which Transparent State Migration has not		In a case in which Transparent State Migration has not
	occurred, the client can use the per-fs grace period provided		occurred, the client can use the per-fs grace period provided
	by the destination server to reclaim locks that were held on		by the destination server to reclaim locks that were held on
	the source server.		the source server.
	</t>		</li>
	<t>		<li>
	In a case in which Transparent State Migration has		In a case in which Transparent State Migration has
	occurred, and no lock state was lost (as shown by SEQ4_STATUS		occurred, and no lock state was lost (as shown by SEQ4_STATUS
	flags), no lock reclaim is necessary.		flags), no lock reclaim is necessary.
	</t>		</li>
	<t>		<li>
	In a case in which Transparent State Migration has		In a case in which Transparent State Migration has
	occurred, and some lock state was lost (as shown by SEQ4_STATUS		occurred, and some lock state was lost (as shown by SEQ4_STATUS
	flags), existing stateids need to be checked for validity		flags), existing stateids need to be checked for validity
	using TEST_STATEID, and reclaim used to re-establish any that		using TEST_STATEID, and reclaim used to re-establish any that
	were not transferred.		were not transferred.
			</li>
	</t>		</ul>
	</list>		<t>
	</t>
	<t>
	For all of the cases above, RECLAIM_COMPLETE with an rca_one_fs		For all of the cases above, RECLAIM_COMPLETE with an rca_one_fs
	value of TRUE needs to be done before		value of TRUE needs to be done before
	normal use of the file system including obtaining new locks for the		normal use of the file system, including obtaining new locks for the
	file system. This applies even if no locks were lost and there		file system. This applies even if no locks were lost and there
	was no need for any to be reclaimed.		was no need for any to be reclaimed.
	</t>		</t>
			</section>
	</section>		<section anchor="V41c-ssnwas" numbered="true" toc="default">
	<section title="Obtaining Access to Sessions and State after Network Address		<name>Obtaining Access to Sessions and State after Network Address Tra
	Transfer"		nsfer</name>
	anchor="V41c-ssnwas">		<t>
	<t>
	The case in which there is a transfer to a new network		The case in which there is a transfer to a new network
	address without migration is similar to that described		address without migration is similar to that described
	in <xref target="V41c-ssmig"/> above in that there is a need to		in <xref target="V41c-ssmig" format="default"/> above in that there is a need to
	obtain access to needed sessions and locking state. However,		obtain access to needed sessions and locking state. However,
	the details are simpler and will vary depending on the		the details are simpler and will vary depending on the
	type of trunking between the address receiving		type of trunking between the address receiving
	NFS4ERR_MOVED and that to which the transfer is to be made		NFS4ERR_MOVED and that to which the transfer is to be made.
	</t>		</t>
	<t>		<t>
	To make a session available for use, a BIND_CONN_TO_SESSION		To make a session available for use, a BIND_CONN_TO_SESSION
	should be used to obtain access to the session previously		should be used to obtain access to the session previously
	in use. Only if this fails, should a CREATE_SESSION be done.		in use. Only if this fails, should a CREATE_SESSION be done.
	While this procedure mirrors that in <xref target="V41c-ssmig"/>		While this procedure mirrors that in <xref target="V41c-ssmig" format="d efault"/>
	above,		above,
	there is an important difference in that preservation of the		there is an important difference in that preservation of the
	session is not purely optional but depends on the type of		session is not purely optional but depends on the type of
	trunking.		trunking.
	</t>		</t>
	<t>		<t>
	Access to appropriate locking state will generally need no actions		Access to appropriate locking state will generally need no actions
	beyond		beyond access to the session. However, the SEQ4_STATUS bits need to be
	access to the session. However, the SEQ4_STATUS bits need to be
	checked for lost locking state, including the need to reclaim		checked for lost locking state, including the need to reclaim
	locks after a server reboot, since there is always a possibility		locks after a server reboot, since there is always a possibility
	of locking state being lost.		of locking state being lost.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section title="Server Responsibilities Upon Migration"		<section anchor="SEC11-trans-server" numbered="true" toc="default">
	anchor="SEC11-trans-server">		<name>Server Responsibilities Upon Migration</name>
	<t>		<t>
	In the event of file system migration, when the client connects		In the event of file system migration, when the client connects
	to the destination server, that server needs to be able to provide the		to the destination server, that server needs to be able to provide the
	client continued to access		client continued access to the files it had open on the source server.
	the files it had open on the source server. There are two ways		There are two ways to provide this:
	to provide this:		</t>
	<list style="symbols">		<ul spacing="normal">
	<t>		<li>
	By provision of an fs-specific grace period, allowing the client the		By provision of an fs-specific grace period, allowing the client the
	ability to reclaim its locks, in a fashion similar to what would		ability to reclaim its locks, in a fashion similar to what would
	have been done in the		have been done in the case of recovery from a server restart. See
	case of recovery from a server restart. See		<xref target="SEC11-XS-reclaim" format="default"/> for a more complete
	<xref target="SEC11-XS-reclaim"/> for a more complete
	discussion.		discussion.
	</t>		</li>
	<t>		<li>
			<t>
	By implementing Transparent State Migration possibly in		By implementing Transparent State Migration possibly in
	connection with session migration, the server can provide		connection with session migration, the server can provide
	the client immediate access to the state built up on the		the client immediate access to the state built up on the
	source server, on the destination.		source server on the destination server.
	<vspace blankLines="1"/>		</t>
			<t>
	These features are discussed separately in Sections		These features are discussed separately in Sections
	<xref target="SEC11-XS-lock" format="counter"/> and		<xref target="SEC11-XS-lock" format="counter"/> and
	<xref target="SEC11-XS-session" format="counter"/>,		<xref target="SEC11-XS-session" format="counter"/>,
	which discuss Transparent State Migration and session		which discuss Transparent State Migration and session
	migration respectively.		migration, respectively.
	</t>		</t>
	</list>		</li>
	</t>		</ul>
	<t>		<t>
	All the features described above can involve transfer of		All the features described above can involve transfer of
	lock-related information between source and destination		lock-related information between source and destination
	servers. In some cases, this transfer is a necessary part		servers. In some cases, this transfer is a necessary part
	of the implementation while in other cases it is a helpful		of the implementation, while in other cases, it is a helpful
	implementation aid which servers might or might not use.		implementation aid, which servers might or might not use.
	The sub-sections below discuss the information which would be		The subsections below discuss the information that would be
	transferred but do not define the specifics of the transfer		transferred but do not define the specifics of the transfer
	protocol. This is left as an implementation choice although		protocol. This is left as an implementation choice, although
	standards in this area could be developed at a later time.		standards in this area could be developed at a later time.
	</t>		</t>
	<section title="Server Responsibilities in Effecting State Reclaim after Mig		<section anchor="SEC11-XS-reclaim" numbered="true" toc="default">
	ration"		<name>Server Responsibilities in Effecting State Reclaim after Migrati
	anchor="SEC11-XS-reclaim">		on</name>
	<t>		<t>
	In this case, the destination server needs no knowledge of		In this case, the destination server needs no knowledge of
	the locks held		the locks held
	on the source server. It relies on the clients to accurately report		on the source server. It relies on the clients to accurately report
	(via reclaim operations) the locks previously held, and does not allow		(via reclaim operations) the locks previously held, and does not allow
	new locks to be granted on migrated file systems until the grace		new locks to be granted on migrated file systems until the grace
	period expires. Disallowing of new locks applies to		period expires. Disallowing of new locks applies to
	all clients accessing these file system, while grace period		all clients accessing these file systems, while grace period
	expiration occurs for each migrated client independently.		expiration occurs for each migrated client independently.
	</t>		</t>
	<t>		<t>
	During this grace period clients have the opportunity to use		During this grace period, clients have the opportunity to use
	reclaim operations to obtain locks for file system objects within		reclaim operations to obtain locks for file system objects within
	the migrated file system, in the same way that they do when		the migrated file system, in the same way that they do when
	recovering from server restart, and the servers typically		recovering from server restart, and the servers typically
	rely on clients to accurately report their locks, although they		rely on clients to accurately report their locks, although they
	have the option of subjecting these requests to verification.		have the option of subjecting these requests to verification.
	If the clients only reclaim locks held on the source server, no		If the clients only reclaim locks held on the source server, no
	conflict can arise. Once the client has reclaimed its locks,		conflict can arise. Once the client has reclaimed its locks,
	it indicates the completion of lock reclamation by performing a		it indicates the completion of lock reclamation by performing a
	RECLAIM_COMPLETE specifying rca_one_fs as TRUE.		RECLAIM_COMPLETE specifying rca_one_fs as TRUE.
			</t>
	</t>		<t>
	<t>
	While it is not necessary for source and destination servers		While it is not necessary for source and destination servers
	to co-operate to transfer information about locks, implementations		to cooperate to transfer information about locks, implementations
	are well-advised to consider transferring the following		are well advised to consider transferring the following
	useful information:		useful information:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	If information about the set of clients that have		If information about the set of clients that have
	locking state for the transferred file system is made available,		locking state for the transferred file system is made available,
	the destination		the destination
	server will be able to terminate the grace period once all		server will be able to terminate the grace period once all
	such clients have reclaimed their locks, allowing normal		such clients have reclaimed their locks, allowing normal
	locking activity to resume earlier than it would have otherwise.		locking activity to resume earlier than it would have otherwise.
	</t>		</li>
	<t>		<li>
	Locking summary information for individual clients (at various		Locking summary information for individual clients (at various
	possible levels of detail) can detect		possible levels of detail) can detect
	some instances in which clients do not accurately represent the		some instances in which clients do not accurately represent the
	locks held on the source server.		locks held on the source server.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section anchor="SEC11-XS-lock" numbered="true" toc="default">
	<section title="Server Responsibilities in Effecting Transparent State Migra		<name>Server Responsibilities in Effecting Transparent State Migration
	tion"		</name>
	anchor="SEC11-XS-lock">		<t>
	<t>
	The basic responsibility of the source server in effecting		The basic responsibility of the source server in effecting
	Transparent State Migration is to make available to the		Transparent State Migration is to make available to the
	destination server a description of each piece of locking state		destination server a description of each piece of locking state
	associated with the file system being migrated. In addition to		associated with the file system being migrated. In addition to
	client id string and verifier, the source server needs to provide,		client id string and verifier, the source server needs to provide
	for each stateid:		for each stateid:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	The stateid including the current sequence value.		The stateid including the current sequence value.
	</t>		</li>
	<t>		<li>
	The associated client ID.		The associated client ID.
	</t>		</li>
	<t>		<li>
	The handle of the associated file.		The handle of the associated file.
	</t>		</li>
	<t>		<li>
	The type of the lock, such as open, byte-range lock, delegation,		The type of the lock, such as open, byte-range lock, delegation,
	or layout.		or layout.
	</t>		</li>
	<t>		<li>
	For locks such as opens and byte-range locks, there will be		For locks such as opens and byte-range locks, there will be
	information about the owner(s) of the lock.		information about the owner(s) of the lock.
	</t>		</li>
	<t>		<li>
	For recallable/revocable lock types, the current recall status		For recallable/revocable lock types, the current recall status
	needs to be included.		needs to be included.
	</t>		</li>
	<t>		<li>
	For each lock type, there will be type-specific information, such		For each lock type, there will be associated type-specific
	as share and deny modes for opens and type and byte ranges for		information. For opens, this will include share and deny mode
	byte-range locks and layouts.		while for byte-range locks and layouts, there will be a type and
	</t>		a byte-range.
	</list>		</li>
	</t>		</ul>
	<t>		<t>
	Such information will most probably be organized by client id string		Such information will most probably be organized by client id string
	on the destination server		on the destination server
	so that it can be used to provide appropriate context to each client		so that it can be used to provide appropriate context to each client
	when it makes itself known to the client. Issues connected with a		when it makes itself known to the client. Issues connected with a
	client impersonating another by presenting another client's client		client impersonating another by presenting another client's client
	id string can be addressed using NFSv4.1 state protection features,		id string can be addressed using NFSv4.1 state protection features,
	as described in <xref target="SECCON"/>.		as described in <xref target="SECCON" format="default"/>.
	</t>		</t>
	<t>		<t>
	A further server responsibility concerns locks that are revoked		A further server responsibility concerns locks that are revoked
	or otherwise lost during the process of file system migration.		or otherwise lost during the process of file system migration.
	Because locks that appear to be lost during the process of		Because locks that appear to be lost during the process of
	migration will be reclaimed by the client, the servers have to		migration will be reclaimed by the client, the servers have to
	take steps to ensure that locks revoked soon before or soon		take steps to ensure that locks revoked soon before or soon
	after migration are not inadvertently allowed to be reclaimed		after migration are not inadvertently allowed to be reclaimed
	in situations in which the continuity of lock possession		in situations in which the continuity of lock possession
	cannot be assured.		cannot be assured.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	For locks lost on the source but whose loss has not yet been		For locks lost on the source but whose loss has not yet been
	acknowledged by the client (by using FREE_STATEID), the		acknowledged by the client (by using FREE_STATEID), the
	destination must be aware of this loss so that it can deny		destination must be aware of this loss so that it can deny
	a request to reclaim them.		a request to reclaim them.
	</t>		</li>
	<t>		<li>
	For locks lost on the destination after the state transfer		For locks lost on the destination after the state transfer
	but before the client's RECLAIM_COMPLTE is done, the		but before the client's RECLAIM_COMPLETE is done, the
	destination server should note these and not allow them to		destination server should note these and not allow them to
	be reclaimed.		be reclaimed.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	An additional responsibility of the cooperating		An additional responsibility of the cooperating
	servers concerns situations		servers concerns situations
	in which a stateid cannot be transferred transparently because it		in which a stateid cannot be transferred transparently because it
	conflicts with an existing stateid held by the client and		conflicts with an existing stateid held by the client and
	associated with a different file system. In this case there		associated with a different file system. In this case, there
	are two valid choices:		are two valid choices:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	Treat the transfer, as in NFSv4.0, as one without Transparent		Treat the transfer, as in NFSv4.0, as one without Transparent
	State Migration. In this case, conflicting locks cannot be		State Migration. In this case, conflicting locks cannot be
	granted until the client does a RECLAIM_COMPLETE, after		granted until the client does a RECLAIM_COMPLETE, after
	reclaiming the locks it had, with the exception of reclaims		reclaiming the locks it had, with the exception of reclaims
	denied because they were attempts to reclaim locks that had		denied because they were attempts to reclaim locks that had
	been lost.		been lost.
	</t>		</li>
	<t>		<li>
	Implement Transparent State Migration, except for the lock		Implement Transparent State Migration, except for the lock
	with the conflicting stateid. In this case, the client will		with the conflicting stateid. In this case, the client will
	be aware of a lost lock (through the SEQ4_STATUS flags) and be		be aware of a lost lock (through the SEQ4_STATUS flags) and be
	allowed to reclaim it.		allowed to reclaim it.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	When transferring state between the source and destination, the		When transferring state between the source and destination, the
	issues discussed in Section 7.2 of <xref target="RFC7931"/>		issues discussed in <xref target="RFC7931" sectionFormat="of" section="7
	must still be attended to. In this case,		.2"/>
	the use of NFS4ERR_DELAY may still		must still be attended to. In this case, the use of NFS4ERR_DELAY may s
			till be
	necessary in NFSv4.1, as it was in NFSv4.0, to prevent locking		necessary in NFSv4.1, as it was in NFSv4.0, to prevent locking
	state changing while it is being transferred. See		state changing while it is being transferred. See
	<xref target="err_DELAY"/> for information about		<xref target="err_DELAY" format="default"/> for information about
	appropriate client retry approaches in the event that NFS4ERR_DELAY		appropriate client retry approaches in the event that NFS4ERR_DELAY
	is returned.		is returned.
	</t>		</t>
	<t>		<t>
	There are a number of important differences in the NFS4.1		There are a number of important differences in the NFS4.1
	context:		context:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	The absence of RELEASE_LOCKOWNER means that the one case		The absence of RELEASE_LOCKOWNER means that the one case
	in which an operation could not be deferred by use of		in which an operation could not be deferred by use of
	NFS4ERR_DELAY no longer exists.		NFS4ERR_DELAY no longer exists.
	</t>		</li>
	<t>		<li>
	Sequencing of operations is no longer done using owner-based		Sequencing of operations is no longer done using owner-based
	operation sequences numbers. Instead, sequencing is session-		operation sequences numbers. Instead, sequencing is session-
	based		based.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	As a result, when sessions are not transferred, the techniques		As a result, when sessions are not transferred, the techniques
	discussed in Section 7.2 of <xref target="RFC7931"/>		discussed in <xref target="RFC7931" sectionFormat="of" section="7.2"/>
	are adequate and will not		are adequate and will not be further discussed.
	be further discussed.		</t>
	</t>		</section>
	</section>		<section anchor="SEC11-XS-session" numbered="true" toc="default">
	<section title="Server Responsibilities in Effecting Session Transfer"		<name>Server Responsibilities in Effecting Session Transfer</name>
	anchor="SEC11-XS-session">		<t>
	<t>
	The basic responsibility of the source server in effecting		The basic responsibility of the source server in effecting
	session transfer is to make available to the		session transfer is to make available to the
	destination server a description of the current state of each		destination server a description of the current state of each
	slot with the session, including:		slot with the session, including the following:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	The last sequence value received for that slot.		The last sequence value received for that slot.
	</t>		</li>
	<t>		<li>
	Whether there is cached reply data for the last request		Whether there is cached reply data for the last request
	executed and, if so, the cached reply.		executed and, if so, the cached reply.
	</t>		</li>
	</list>		</ul>
			<t>
	</t>
	<t>
	When sessions are transferred, there are a number of issues that		When sessions are transferred, there are a number of issues that
	pose challenges in terms of making the transferred state		pose challenges in terms of making the transferred state
	unmodifiable during the period it is gathered up and		unmodifiable during the period it is gathered up and
	transferred to the destination server.		transferred to the destination server:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	A single session may be used to access multiple file systems,		A single session may be used to access multiple file systems,
	not all of which are being transferred.		not all of which are being transferred.
	</t>		</li>
	<t>		<li>
	Requests made on a session may, even if rejected, affect		Requests made on a session may, even if rejected, affect
	the state of the session by advancing the sequence number		the state of the session by advancing the sequence number
	associated with the slot used.		associated with the slot used.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	As a result, when the file system state might otherwise be		As a result, when the file system state might otherwise be
	considered unmodifiable, the client might have any number of		considered unmodifiable, the client might have any number of
	in-flight requests, each of which is capable of changing session		in-flight requests, each of which is capable of changing session
	state, which may be of a number of types:		state, which may be of a number of types:
	<list style ='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
	Those requests that were processed on the migrating file system,		<li>
			Those requests that were processed on the migrating file system
	before migration began.		before migration began.
	</t>		</li>
	<t>		<li>
	Those requests which got the error NFS4ERR_DELAY because the		Those requests that received the error NFS4ERR_DELAY because the
	file system being accessed was in the process of being		file system being accessed was in the process of being
	migrated.		migrated.
	</t>		</li>
	<t>		<li>
	Those requests which got the error NFS4ERR_MOVED because the		Those requests that received the error NFS4ERR_MOVED because the
	file system being accessed had been migrated.		file system being accessed had been migrated.
	</t>		</li>
	<t>		<li>
	Those requests that accessed the migrating file system,		Those requests that accessed the migrating file system
	in order to obtain location or status information.		in order to obtain location or status information.
	</t>		</li>
	<t>		<li>
	Those requests that did not reference the migrating file system.		Those requests that did not reference the migrating file system.
	</t>		</li>
	</list>		</ol>
	</t>		<t>
	<t>		It should be noted that the history of any particular slot is likely
	It should be noted that the history of any
	particular slot is likely
	to include a number of these request classes. In the case in which		to include a number of these request classes. In the case in which
	a session which is migrated is used by file systems other than the		a session that is migrated is used by file systems other than the
	one migrated, requests of class 5 may be common and be the last		one migrated, requests of class 5 may be common and may be the last
	request processed, for many slots.		request processed for many slots.
	</t>		</t>
	<t>		<t>
	Since session state can change even after the locking		Since session state can change even after the locking
	state has been fixed as part of the migration process,		state has been fixed as part of the migration process,
	the session state known to the client could		the session state known to the client could be different from that on
	be different from that on
	the destination server, which necessarily reflects the session		the destination server, which necessarily reflects the session
	state on the source server, at an earlier time.		state on the source server at an earlier time.
	In deciding how to deal with this situation, it is helpful to		In deciding how to deal with this situation, it is helpful to
	distinguish between two sorts of behavioral consequences of		distinguish between two sorts of behavioral consequences of
	the choice of initial sequence ID values.		the choice of initial sequence ID values:
	<list style ='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	The error NFS4ERR_SEQ_MISORDERED is returned when the sequence ID		The error NFS4ERR_SEQ_MISORDERED is returned when the sequence ID
	in a request is neither equal to the last one seen for the		in a request is neither equal to the last one seen for the
	current slot nor the next greater one.		current slot nor the next greater one.
	<vspace blankLines='1' />		</t>
			<t>
	In view of the difficulty of arriving at a mutually acceptable		In view of the difficulty of arriving at a mutually acceptable
	value for the correct last sequence value		value for the correct last sequence value at the point of migration,
	at the point of migration,
	it may be necessary for the server to show some degree of		it may be necessary for the server to show some degree of
	forbearance, when the sequence ID is one that would be		forbearance when the sequence ID is one that would be
	considered unacceptable if session migration were not		considered unacceptable if session migration were not
	involved.		involved.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	Returning the cached reply for a previously executed		Returning the cached reply for a previously executed
	request when the sequence ID		request when the sequence ID
	in the request matches the last value recorded for the slot.		in the request matches the last value recorded for the slot.
	<vspace blankLines='1' />		</t>
			<t>
	In the cases in which an error is returned and there is no		In the cases in which an error is returned and there is no
	possibility of any non-idempotent operation having been executed,		possibility of any non-idempotent operation having been executed,
	it may not be necessary to adhere to this as strictly as might		it may not be necessary to adhere to this as strictly as might
	be proper if session migration were not		be proper if session migration were not involved. For example,
	involved. For example, the fact that the error NFS4ERR_DELAY		the fact that the error NFS4ERR_DELAY
	was returned may not assist the client in any material way, while		was returned may not assist the client in any material way, while
	the fact that NFS4ERR_MOVED was returned by the source server		the fact that NFS4ERR_MOVED was returned by the source server
	may not be relevant when the request was reissued, directed		may not be relevant when the request was reissued and directed
	to the		to the destination server.
	destination server.		</t>
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	An important issue is that the specification needs to take note of		An important issue is that the specification needs to take note of
	all potential COMPOUNDs, even if they might be unlikely		all potential COMPOUNDs, even if they might be unlikely
	in practice. For example, a COMPOUND is allowed to access		in practice. For example, a COMPOUND is allowed to access
	multiple file systems and might perform non-idempotent operations		multiple file systems and might perform non-idempotent operations
	in some of them before accessing a file system being migrated.		in some of them before accessing a file system being migrated.
	Also, a COMPOUND may return considerable data in the response,		Also, a COMPOUND may return considerable data in the response
	before		before being rejected with NFS4ERR_DELAY or NFS4ERR_MOVED, and may
	being rejected with NFS4ERR_DELAY or NFS4ERR_MOVED, and may
	in addition be marked as sa_cachethis. However, note that		in addition be marked as sa_cachethis. However, note that
	if the client and server adhere to rules in		if the client and server adhere to rules in
	<xref target="err_DELAY"/>, there is no possibility of		<xref target="err_DELAY" format="default"/>, there is no possibility of
	non-idempotent operations being spuriously reissued after receiving		non-idempotent operations being spuriously reissued after receiving
	NFS4ERR_DELAY response.		NFS4ERR_DELAY response.
	</t>		</t>
	<t>		<t>
	To address these issues, a destination server MAY do any of		To address these issues, a destination server <bcp14>MAY</bcp14> do any
	the following when implementing session transfer.		of
	<list style ='symbols'>		the following when implementing session transfer:
	<t>		</t>
			<ul spacing="normal">
			<li>
	Avoid enforcing any sequencing semantics for a particular slot		Avoid enforcing any sequencing semantics for a particular slot
	until the client has established the starting sequence for that		until the client has established the starting sequence for that
	slot on the destination server.		slot on the destination server.
	</t>		</li>
	<t>		<li>
	For each slot, avoid		For each slot, avoid
	returning a cached reply returning NFS4ERR_DELAY or NFS4ERR_MOVED		returning a cached reply returning NFS4ERR_DELAY or NFS4ERR_MOVED
	until the client has established the starting sequence for that		until the client has established the starting sequence for that
	slot on the destination server.		slot on the destination server.
	</t>		</li>
	<t>		<li>
	Until the client has established the starting sequence for a		Until the client has established the starting sequence for a
	particular slot on the destination server,		particular slot on the destination server, avoid reporting
	avoid reporting NFS4ERR_SEQ_MISORDERED or		NFS4ERR_SEQ_MISORDERED or returning a cached reply that contains
	returning a cached reply returning NFS4ERR_DELAY or NFS4ERR_MOVED,		either NFS4ERR_DELAY or NFS4ERR_MOVED and consists solely of
	where the reply consists solely of a series of operations		a series of operations where the response is NFS4_OK until the
	where the response is NFS4_OK until the final error.		final error.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		Because of the considerations mentioned above, including the rules
	Because of the considerations mentioned above including the rules
	for the handling of NFS4ERR_DELAY included in		for the handling of NFS4ERR_DELAY included in
	<xref target="err_DELAY"/>, the destination		<xref target="err_DELAY" format="default"/>, the destination
	server can respond appropriately to SEQUENCE operations received		server can respond appropriately to SEQUENCE operations received
	from the client by adopting the three policies listed below:		from the client by adopting the three policies listed below:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Not responding with NFS4ERR_SEQ_MISORDERED for the initial		Not responding with NFS4ERR_SEQ_MISORDERED for the initial
	request on a slot within a transferred session, since the		request on a slot within a transferred session because the
	destination server cannot be aware of requests made by the		destination server cannot be aware of requests made by the
	client after the server handoff but before the client became		client after the server handoff but before the client became
	aware of the shift. In cases in which NFS4ERR_SEQ_MISORDERED		aware of the shift. In cases in which NFS4ERR_SEQ_MISORDERED
	would normally have been reported, the request is to be processed		would normally have been reported, the request is to be processed
	normally, as a new request.		normally as a new request.
	</t>		</li>
	<t>		<li>
	Replying as it would for a retry whenever the sequence matches		Replying as it would for a retry whenever the sequence matches
	that transferred by the source server, even though this would		that transferred by the source server, even though this would
	not provide retry handling for requests issued after the server		not provide retry handling for requests issued after the server
	handoff, under the assumption that when such requests are issued		handoff, under the assumption that, when such requests are issued,
	they will never be responded to in a state-changing fashion,		they will never be responded to in a state-changing fashion,
	making retry support for them unnecessary.		making retry support for them unnecessary.
	</t>		</li>
	<t>		<li>
	Once a non-retry SEQUENCE is received for a given slot, using		Once a non-retry SEQUENCE is received for a given slot, using
	that as the basis for further sequence checking, with no further		that as the basis for further sequence checking, with no further
	reference to the sequence value transferred by the source.		reference to the sequence value transferred by the source server.
	server.		</li>
	</t>		</ul>
	</list>		</section>
	</t>		</section>
			<section anchor="effecting_referrals" numbered="true" toc="default">
	</section>		<name>Effecting File System Referrals</name>
	</section>		<t>
	<section anchor="effecting_referrals"
	title="Effecting File System Referrals">
	<t>
	Referrals are effected when an absent file system is encountered		Referrals are effected when an absent file system is encountered
	and one or more alternate locations are made available by the		and one or more alternate locations are made available by the
	fs_locations or fs_locations_info attributes. The client will		fs_locations or fs_locations_info attributes. The client will
	typically get an NFS4ERR_MOVED error, fetch the appropriate		typically get an NFS4ERR_MOVED error, fetch the appropriate
	location information, and proceed to access the file system on		location information, and proceed to access the file system on
	a different server, even though it retains its logical position		a different server, even though it retains its logical position
	within the original namespace. Referrals differ from migration		within the original namespace. Referrals differ from migration
	events in that they happen only when the client has not		events in that they happen only when the client has not
	previously referenced the file system in question (so there		previously referenced the file system in question (so there
	is nothing to transition). Referrals can only come into		is nothing to transition). Referrals can only come into
	effect when an absent file system is encountered at its		effect when an absent file system is encountered at its
	root.		root.
	</t>		</t>
	<t>		<t>
	The examples given in the sections below are somewhat artificial in		The examples given in the sections below are somewhat artificial in
	that an actual client will not typically do a multi-component		that an actual client will not typically do a multi-component
	look up, but will have cached information regarding the upper levels		look up, but will have cached information regarding the upper levels
	of the name hierarchy. However, these examples are chosen to make		of the name hierarchy. However, these examples are chosen to make
	the required behavior clear and easy to put within the scope of a		the required behavior clear and easy to put within the scope of a
	small number of requests, without getting a discussion of the details of		small number of requests, without getting into a discussion of the details of
	how specific clients might choose to cache things.		how specific clients might choose to cache things.
	</t>		</t>
	<section anchor="referrals_lookup"		<section anchor="referrals_lookup" numbered="true" toc="default">
	title="Referral Example (LOOKUP)">		<name>Referral Example (LOOKUP)</name>
	<t>		<t>
	Let us suppose that the following COMPOUND is sent in an		Let us suppose that the following COMPOUND is sent in an
	environment in which /this/is/the/path is absent from the		environment in which /this/is/the/path is absent from the
	target server. This may be for a number of reasons. It may		target server. This may be for a number of reasons. It may
	be that the file system has moved, or it may be that		be that the file system has moved, or it may be that
	the target server is functioning mainly, or solely, to refer		the target server is functioning mainly, or solely, to refer
	clients to the servers on which various file systems are located.		clients to the servers on which various file systems are located.
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	PUTROOTFH		PUTROOTFH
	</t>		</li>
	<t>		<li>
	LOOKUP "this"		LOOKUP "this"
	</t>		</li>
	<t>		<li>
	LOOKUP "is"		LOOKUP "is"
	</t>		</li>
	<t>		<li>
	LOOKUP "the"		LOOKUP "the"
	</t>		</li>
	<t>		<li>
	LOOKUP "path"		LOOKUP "path"
	</t>		</li>
	<t>		<li>
	GETFH		GETFH
	</t>		</li>
	<t>		<li>
	GETATTR (fsid, fileid, size, time_modify)		GETATTR (fsid, fileid, size, time_modify)
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Under the given circumstances, the following will be the result.		Under the given circumstances, the following will be the result.
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>		PUTROOTFH --&gt; NFS_OK. The current fh is now the root of
	PUTROOTFH --> NFS_OK. The current fh is now the root of
	the pseudo-fs.		the pseudo-fs.
	</t>		</li>
	<t>		<li>
	LOOKUP "this" --> NFS_OK. The current fh is for /this and is		LOOKUP "this" --&gt; NFS_OK. The current fh is for /this and is
	within the pseudo-fs.		within the pseudo-fs.
	</t>		</li>
	<t>		<li>
	LOOKUP "is" --> NFS_OK. The current fh is for /this/is		LOOKUP "is" --&gt; NFS_OK. The current fh is for /this/is
	and is within the pseudo-fs.		and is within the pseudo-fs.
	</t>		</li>
	<t>		<li>
	LOOKUP "the" --> NFS_OK. The current fh is for /this/is/the		LOOKUP "the" --&gt; NFS_OK. The current fh is for /this/is/the
	and is within the pseudo-fs.		and is within the pseudo-fs.
	</t>		</li>
	<t>		<li>
	LOOKUP "path" --> NFS_OK. The current fh is for		LOOKUP "path" --&gt; NFS_OK. The current fh is for
	/this/is/the/path and is within a new, absent file system, but ...		/this/is/the/path and is within a new, absent file system, but ...
	the client will never see the value of that fh.		the client will never see the value of that fh.
	</t>		</li>
	<t>		<li>
	GETFH --> NFS4ERR_MOVED.		GETFH --&gt; NFS4ERR_MOVED.
	Fails because current fh is in an absent file system at the start of		Fails because current fh is in an absent file system at the start of
	the operation, and the specification makes no exception for GETFH.		the operation, and the specification makes no exception for GETFH.
	</t>		</li>
	<t>		<li>
	GETATTR (fsid, fileid, size, time_modify).		GETATTR (fsid, fileid, size, time_modify).
	Not executed because the failure of the GETFH stops processing		Not executed because the failure of the GETFH stops processing
	of the COMPOUND.		of the COMPOUND.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Given the failure of the GETFH, the client has the job of		Given the failure of the GETFH, the client has the job of
	determining the root of the absent file system and where to find		determining the root of the absent file system and where to find
	that file system, i.e., the server and path relative to that		that file system, i.e., the server and path relative to that
	server's root fh. Note that in this example, the client did		server's root fh. Note that in this example, the client did
	not obtain filehandles and attribute information (e.g., fsid) for		not obtain filehandles and attribute information (e.g., fsid) for
	the intermediate directories, so that it would not be sure where		the intermediate directories, so that it would not be sure where
	the absent file system starts. It could be the case, for example,		the absent file system starts. It could be the case, for example,
	that /this/is/the is the root of the moved file system and that		that /this/is/the is the root of the moved file system and that
	the reason that the look up of "path" succeeded is that the		the reason that the look up of "path" succeeded is that the
	file system was not absent on that operation but was moved between the l ast		file system was not absent on that operation but was moved between the l ast
	LOOKUP and the GETFH (since COMPOUND is not atomic). Even if we		LOOKUP and the GETFH (since COMPOUND is not atomic). Even if we
	had the fsids for all of the intermediate directories, we could		had the fsids for all of the intermediate directories, we could
	have no way of knowing that /this/is/the/path was the root of a		have no way of knowing that /this/is/the/path was the root of a
	new file system, since we don't yet have its fsid.		new file system, since we don't yet have its fsid.
	</t>		</t>
	<t>		<t>
	In order to get the necessary information, let us re-send the		In order to get the necessary information, let us re-send the
	chain of LOOKUPs with GETFHs and GETATTRs to at least get the		chain of LOOKUPs with GETFHs and GETATTRs to at least get the
	fsids so we can be sure where the appropriate file system boundaries are .		fsids so we can be sure where the appropriate file system boundaries are .
	The client could choose to get fs_locations_info		The client could choose to get fs_locations_info
	at the same time but in		at the same time but in
	most cases the client will have a good guess as to where file system		most cases the client will have a good guess as to where file system
	boundaries are (because of where NFS4ERR_MOVED was, and was not,		boundaries are (because of where NFS4ERR_MOVED was, and was not,
	received) making fetching of fs_locations_info unnecessary.		received) making fetching of fs_locations_info unnecessary.
	</t>		</t>
	<t>		<dl newline="false" spacing="normal">
	<list style='hanging'>		<dt>OP01:</dt>
	<t hangText='OP01:'>		<dd><t>PUTROOTFH --&gt; NFS_OK</t>
	PUTROOTFH --> NFS_OK		<ul><li>Current fh is root of pseudo-fs.</li></ul>
	</t>		</dd>
	<t hangText='- '>		<dt>OP02:</dt>
	Current fh is root of pseudo-fs.		<dd><t>GETATTR(fsid) --&gt; NFS_OK</t>
	</t>		<ul><li>Just for completeness. Normally, clients will know the fsid
	<t hangText='OP02:'>
	GETATTR(fsid) --> NFS_OK
	</t>
	<t hangText='- '>
	Just for completeness. Normally, clients will know the fsid
	of the pseudo-fs as soon as they establish communication with		of the pseudo-fs as soon as they establish communication with
	a server.		a server.</li></ul>
	</t>		</dd>
	<t hangText='OP03:'>		<dt>OP03:</dt>
	LOOKUP "this" --> NFS_OK		<dd>LOOKUP "this" --&gt; NFS_OK</dd>
	</t>		<dt>OP04:</dt>
	<t hangText='OP04:'>		<dd><t>GETATTR(fsid) --&gt; NFS_OK</t>
	GETATTR(fsid) --> NFS_OK		<ul><li>
	</t>		Get current fsid to see where file system boundaries are. The fsid
	<t hangText='- '>
	Get current fsid to see where file system boundaries are. The fsid
	will be that for the pseudo-fs in this example, so no		will be that for the pseudo-fs in this example, so no
	boundary.		boundary.</li></ul>
	</t>		</dd>
	<t hangText='OP05:'>		<dt>OP05:</dt>
	GETFH --> NFS_OK		<dd><t>GETFH --&gt; NFS_OK</t>
	</t>		<ul><li>Current fh is for /this and is within pseudo-fs.</li></ul>
	<t hangText='- '>		</dd>
	Current fh is for /this and is within pseudo-fs.		<dt>OP06:</dt>
	</t>		<dd><t>LOOKUP "is" --&gt; NFS_OK</t>
	<t hangText='OP06:'>		<ul><li>Current fh is for /this/is and is within pseudo-fs.</li></ul>
	LOOKUP "is" --> NFS_OK		</dd>
	</t>		<dt>OP07:</dt>
	<t hangText='- '>		<dd><t>GETATTR(fsid) --&gt; NFS_OK</t>
	Current fh is for /this/is and is within pseudo-fs.		<ul><li>
	</t>
	<t hangText='OP07:'>
	GETATTR(fsid) --> NFS_OK
	</t>
	<t hangText='- '>
	Get current fsid to see where file system boundaries are. The fsid		Get current fsid to see where file system boundaries are. The fsid
	will be that for the pseudo-fs in this example, so no		will be that for the pseudo-fs in this example, so no
	boundary.		boundary.</li></ul>
	</t>		</dd>
	<t hangText='OP08:'>		<dt>OP08:</dt>
	GETFH --> NFS_OK		<dd>
	</t>		<t>GETFH --&gt; NFS_OK</t>
	<t hangText='- '>		<ul><li>Current fh is for /this/is and is within pseudo-fs.</li></ul>
	Current fh is for /this/is and is within pseudo-fs.		</dd>
	</t>		<dt>OP09:</dt>
	<t hangText='OP09:'>		<dd>
	LOOKUP "the" --> NFS_OK		<t>LOOKUP "the" --&gt; NFS_OK</t>
	</t>		<ul><li>
	<t hangText='- '>		Current fh is for /this/is/the and is within pseudo-fs.</li></ul>
	Current fh is for /this/is/the and is within pseudo-fs.		</dd>
	</t>		<dt>OP10:</dt>
	<t hangText='OP10:'>		<dd>
	GETATTR(fsid) --> NFS_OK		<t>GETATTR(fsid) --&gt; NFS_OK</t>
	</t>		<ul><li>
	<t hangText='- '>		Get current fsid to see where file system boundaries are. The fsid
	Get current fsid to see where file system boundaries are. The fsid
	will be that for the pseudo-fs in this example, so no		will be that for the pseudo-fs in this example, so no
	boundary.		boundary.</li></ul>
	</t>		</dd>
	<t hangText='OP11:'>		<dt>OP11:</dt>
	GETFH --> NFS_OK		<dd>
	</t>		<t>GETFH --&gt; NFS_OK</t>
	<t hangText='- '>		<ul><li>Current fh is for /this/is/the and is within pseudo-fs.</li></
	Current fh is for /this/is/the and is within pseudo-fs.		ul>
	</t>		</dd>
	<t hangText='OP12:'>		<dt>OP12:</dt>
	LOOKUP "path" --> NFS_OK		<dd>
	</t>		<t>LOOKUP "path" --&gt; NFS_OK</t>
	<t hangText='- '>		<ul><li>
	Current fh is for /this/is/the/path and is within a new,		Current fh is for /this/is/the/path and is within a new,
	absent file system, but ...		absent file system, but ...</li>
	</t>		<li>
	<t hangText='- '>		The client will never see the value of that fh.</li></ul>
	The client will never see the value of that fh.		</dd>
	</t>		<dt>OP13:</dt>
	<t hangText='OP13:'>		<dd>
	GETATTR(fsid, fs_locations_info) --> NFS_OK		<t>GETATTR(fsid, fs_locations_info) --&gt; NFS_OK</t>
	</t>		<ul><li>
	<t hangText='- '>
	We are getting the fsid to know where the file system boundaries are.		We are getting the fsid to know where the file system boundaries are.
	In this operation, the fsid will be different than that of the		In this operation, the fsid will be different than that of the
	parent directory (which in turn was retrieved in OP10).		parent directory (which in turn was retrieved in OP10).
	Note that the fsid we are given will not necessarily be preserved at t he new		Note that the fsid we are given will not necessarily be preserved at t he new
	location. That fsid might be different, and in fact the fsid		location. That fsid might be different, and in fact the fsid
	we have for this file system might be a valid fsid of a different		we have for this file system might be a valid fsid of a different
	file system on that new server.		file system on that new server.</li>
	</t>		<li>
	<t hangText='- '>
	In this particular case, we are pretty sure anyway that what		In this particular case, we are pretty sure anyway that what
	has moved is /this/is/the/path rather than /this/is/the		has moved is /this/is/the/path rather than /this/is/the
	since we have the fsid of the latter and it is that of the		since we have the fsid of the latter and it is that of the
	pseudo-fs, which presumably cannot move. However, in other		pseudo-fs, which presumably cannot move. However, in other
	examples, we might not have this kind of information to rely		examples, we might not have this kind of information to rely
	on (e.g., /this/is/the might be a non-pseudo file system		on (e.g., /this/is/the might be a non-pseudo file system
	separate from /this/is/the/path), so we need to have		separate from /this/is/the/path), so we need to have
	other reliable source information on the boundary of the file system		other reliable source information on the boundary of the file system
	that is moved. If, for example, the file system /this/is		that is moved. If, for example, the file system /this/is
	had moved, we would have a case of migration rather than		had moved, we would have a case of migration rather than
	referral, and once the boundaries of the migrated file system		referral, and once the boundaries of the migrated file system
	was clear we could fetch fs_locations_info.		was clear we could fetch fs_locations_info.</li>
	</t>		<li>
	<t hangText='- '>
	We are fetching fs_locations_info because the fact that we got an		We are fetching fs_locations_info because the fact that we got an
	NFS4ERR_MOVED at this point means that it is most likely that		NFS4ERR_MOVED at this point means that it is most likely that
	this is a referral and we need the destination. Even if it is		this is a referral and we need the destination. Even if it is
	the case that /this/is/the is a file system that has		the case that /this/is/the is a file system that has
	migrated, we will still need the location information for that		migrated, we will still need the location information for that
	file system.		file system.</li></ul></dd>
	</t>
	<t hangText='OP14:'>		<dt>OP14:</dt>
	GETFH --> NFS4ERR_MOVED		<dd>
	</t>		<t>GETFH --&gt; NFS4ERR_MOVED</t>
	<t hangText='- '>		<ul><li>
	Fails because current fh is in an absent file system at the start of		Fails because current fh is in an absent file system at the start of
	the operation, and the specification makes no exception for GETFH. No te		the operation, and the specification makes no exception for GETFH. No te
	that this means the server will never send the client a		that this means the server will never send the client a
	filehandle from within an absent file system.		filehandle from within an absent file system.</li></ul>
	</t>		</dd>
	</list>		</dl>
	</t>		<t>
	<t>
	Given the above, the client knows where the root of the absent file		Given the above, the client knows where the root of the absent file
	system is (/this/is/the/path) by noting where the change of		system is (/this/is/the/path) by noting where the change of
	fsid occurred (between "the" and "path"). The		fsid occurred (between "the" and "path"). The
	fs_locations_info attribute also gives the client the		fs_locations_info attribute also gives the client the
	actual location of		actual location of
	the absent file system, so that the referral can proceed. The		the absent file system, so that the referral can proceed. The
	server gives the client the bare minimum of information about the		server gives the client the bare minimum of information about the
	absent file system so that there will be very little scope for		absent file system so that there will be very little scope for
	problems of conflict between information sent by the referring		problems of conflict between information sent by the referring
	server and information of the file system's home. No filehandles		server and information of the file system's home. No filehandles
	and very few attributes are present on the referring server, and the		and very few attributes are present on the referring server, and the
	client can treat those it receives as transient		client can treat those it receives as transient
	information with the function of enabling the referral.		information with the function of enabling the referral.
	</t>		</t>
	</section>		</section>
	<section anchor="referrals_readdir"		<section anchor="referrals_readdir" numbered="true" toc="default">
	title="Referral Example (READDIR)">		<name>Referral Example (READDIR)</name>
	<t>		<t>
	Another context in which a client may encounter referrals is when		Another context in which a client may encounter referrals is when
	it does a READDIR on a directory in which some of the sub-directories		it does a READDIR on a directory in which some of the sub-directories
	are the roots of absent file systems.		are the roots of absent file systems.
	</t>		</t>
	<t>		<t>
	Suppose such a directory is read as follows:		Suppose such a directory is read as follows:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	PUTROOTFH		PUTROOTFH
	</t>		</li>
	<t>		<li>
	LOOKUP "this"		LOOKUP "this"
	</t>		</li>
	<t>		<li>
	LOOKUP "is"		LOOKUP "is"
	</t>		</li>
	<t>		<li>
	LOOKUP "the"		LOOKUP "the"
	</t>		</li>
	<t>		<li>
	READDIR (fsid, size, time_modify, mounted_on_fileid)		READDIR (fsid, size, time_modify, mounted_on_fileid)
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	In this case, because rdattr_error is not requested,		In this case, because rdattr_error is not requested,
	fs_locations_info		fs_locations_info
	is not requested, and some of the attributes cannot be provided, the		is not requested, and some of the attributes cannot be provided, the
	result will be an NFS4ERR_MOVED error on the READDIR, with the		result will be an NFS4ERR_MOVED error on the READDIR, with the
	detailed results as follows:		detailed results as follows:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>		PUTROOTFH --&gt; NFS_OK. The current fh is at the root of the
	PUTROOTFH --> NFS_OK. The current fh is at the root of the
	pseudo-fs.		pseudo-fs.
	</t>		</li>
	<t>		<li>
	LOOKUP "this" --> NFS_OK. The current fh is for /this and is		LOOKUP "this" --&gt; NFS_OK. The current fh is for /this and is
	within the pseudo-fs.		within the pseudo-fs.
	</t>		</li>
	<t>		<li>
	LOOKUP "is" --> NFS_OK. The current fh is for /this/is		LOOKUP "is" --&gt; NFS_OK. The current fh is for /this/is
	and is within the pseudo-fs.		and is within the pseudo-fs.
	</t>		</li>
	<t>		<li>
	LOOKUP "the" --> NFS_OK. The current fh is for /this/is/the		LOOKUP "the" --&gt; NFS_OK. The current fh is for /this/is/the
	and is within the pseudo-fs.		and is within the pseudo-fs.
	</t>		</li>
	<t>		<li>
	READDIR (fsid, size, time_modify, mounted_on_fileid) -->		READDIR (fsid, size, time_modify, mounted_on_fileid) --&gt;
	NFS4ERR_MOVED. Note that the same error would have been		NFS4ERR_MOVED. Note that the same error would have been
	returned if /this/is/the had migrated, but it is returned because the		returned if /this/is/the had migrated, but it is returned because the
	directory contains the root of an absent file system.		directory contains the root of an absent file system.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	So now suppose that we re-send with rdattr_error:		So now suppose that we re-send with rdattr_error:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	PUTROOTFH		PUTROOTFH
	</t>		</li>
	<t>		<li>
	LOOKUP "this"		LOOKUP "this"
	</t>		</li>
	<t>		<li>
	LOOKUP "is"		LOOKUP "is"
	</t>		</li>
	<t>		<li>
	LOOKUP "the"		LOOKUP "the"
	</t>		</li>
	<t>		<li>
	READDIR (rdattr_error, fsid, size, time_modify, mounted_on_fileid)		READDIR (rdattr_error, fsid, size, time_modify, mounted_on_fileid)
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The results will be:		The results will be:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>		PUTROOTFH --&gt; NFS_OK. The current fh is at the root of the
	PUTROOTFH --> NFS_OK. The current fh is at the root of the
	pseudo-fs.		pseudo-fs.
	</t>		</li>
	<t>		<li>
	LOOKUP "this" --> NFS_OK. The current fh is for /this and is		LOOKUP "this" --&gt; NFS_OK. The current fh is for /this and is
	within the pseudo-fs.		within the pseudo-fs.
	</t>		</li>
	<t>		<li>
	LOOKUP "is" --> NFS_OK. The current fh is for /this/is		LOOKUP "is" --&gt; NFS_OK. The current fh is for /this/is
	and is within the pseudo-fs.		and is within the pseudo-fs.
	</t>		</li>
	<t>		<li>
	LOOKUP "the" --> NFS_OK. The current fh is for /this/is/the		LOOKUP "the" --&gt; NFS_OK. The current fh is for /this/is/the
	and is within the pseudo-fs.		and is within the pseudo-fs.
	</t>		</li>
	<t>		<li>
	READDIR (rdattr_error, fsid, size, time_modify, mounted_on_fileid)		READDIR (rdattr_error, fsid, size, time_modify, mounted_on_fileid)
	--> NFS_OK. The attributes for directory entry with the		--&gt; NFS_OK. The attributes for directory entry with the
	component named "path" will only contain		component named "path" will only contain
	rdattr_error		rdattr_error
	with the value NFS4ERR_MOVED, together with an fsid		with the value NFS4ERR_MOVED, together with an fsid
	value and a value for mounted_on_fileid.		value and a value for mounted_on_fileid.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Suppose we do another READDIR to get fs_locations_info (although		Suppose we do another READDIR to get fs_locations_info (although
	we could have used a GETATTR directly, as in		we could have used a GETATTR directly, as in
	<xref target="referrals_lookup" />).		<xref target="referrals_lookup" format="default"/>).
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	PUTROOTFH		PUTROOTFH
	</t>		</li>
	<t>		<li>
	LOOKUP "this"		LOOKUP "this"
	</t>		</li>
	<t>		<li>
	LOOKUP "is"		LOOKUP "is"
	</t>		</li>
	<t>		<li>
	LOOKUP "the"		LOOKUP "the"
	</t>		</li>
	<t>		<li>
	READDIR (rdattr_error, fs_locations_info, mounted_on_fileid, fsid,		READDIR (rdattr_error, fs_locations_info, mounted_on_fileid, fsid,
	size, time_modify)		size, time_modify)
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The results would be:		The results would be:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>		PUTROOTFH --&gt; NFS_OK. The current fh is at the root of the
	PUTROOTFH --> NFS_OK. The current fh is at the root of the
	pseudo-fs.		pseudo-fs.
	</t>		</li>
	<t>		<li>
	LOOKUP "this" --> NFS_OK. The current fh is for /this and is		LOOKUP "this" --&gt; NFS_OK. The current fh is for /this and is
	within the pseudo-fs.		within the pseudo-fs.
	</t>		</li>
	<t>		<li>
	LOOKUP "is" --> NFS_OK. The current fh is for /this/is		LOOKUP "is" --&gt; NFS_OK. The current fh is for /this/is
	and is within the pseudo-fs.		and is within the pseudo-fs.
	</t>		</li>
	<t>		<li>
	LOOKUP "the" --> NFS_OK. The current fh is for /this/is/the		LOOKUP "the" --&gt; NFS_OK. The current fh is for /this/is/the
	and is within the pseudo-fs.		and is within the pseudo-fs.
	</t>		</li>
	<t>		<li>
	READDIR (rdattr_error, fs_locations_info, mounted_on_fileid, fsid,		READDIR (rdattr_error, fs_locations_info, mounted_on_fileid, fsid,
	size, time_modify) --> NFS_OK. The attributes will be as shown below.		size, time_modify) --&gt; NFS_OK. The attributes will be as shown bel
	</t>		ow.
	</list>		</li>
	</t>		</ul>
	<t>		<t>
	The attributes for the directory entry with the		The attributes for the directory entry with the
	component named "path" will only contain:		component named "path" will only contain:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	rdattr_error (value: NFS_OK)		rdattr_error (value: NFS_OK)
	</t>		</li>
	<t>		<li>
	fs_locations_info		fs_locations_info
	</t>		</li>
	<t>		<li>
	mounted_on_fileid (value: unique fileid within referring file system)		mounted_on_fileid (value: unique fileid within referring file system)
	</t>		</li>
	<t>		<li>
	fsid (value: unique value within referring server)		fsid (value: unique value within referring server)
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The attributes for entry "path" will not contain size or		The attributes for entry "path" will not contain size or
	time_modify because these attributes are not available within an		time_modify because these attributes are not available within an
	absent file system.		absent file system.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section anchor="fs_locations"		<section anchor="fs_locations" numbered="true" toc="default">
	title="The Attribute fs_locations">		<name>The Attribute fs_locations</name>
	<t>		<t>
	The fs_locations attribute is structured in the following way:		The fs_locations attribute is structured in the following way:
	</t>		</t>
	<t>		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct fs_location4 {		struct fs_location4 {
	utf8str_cis server&lt;>;		utf8str_cis server<>;
	pathname4 rootpath;		pathname4 rootpath;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<sourcecode type="xdr"><![CDATA[
	</t>
	<t>
	<figure>
	<artwork>
	struct fs_locations4 {		struct fs_locations4 {
	pathname4 fs_root;		pathname4 fs_root;
	fs_location4 locations&lt;>;		fs_location4 locations<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	</t>
	<t>
	The fs_location4 data type is used to represent the location of a		The fs_location4 data type is used to represent the location of a
	file system by providing a server name and the path to the root		file system by providing a server name and the path to the root
	of the file system within that server's namespace.		of the file system within that server's namespace.
	When a set of servers have corresponding file systems at the		When a set of servers have corresponding file systems at the
	same path within their namespaces, an array of server names may		same path within their namespaces, an array of server names may
	be provided. An		be provided. An
	entry in the server array is a UTF-8 string and represents one		entry in the server array is a UTF-8 string and represents one
	of a		of a
	traditional DNS host name, IPv4 address, IPv6 address, or a		traditional DNS host name, IPv4 address, IPv6 address, or a
	zero-length string.		zero-length string.
	An IPv4 or IPv6 address is represented as a universal		An IPv4 or IPv6 address is represented as a universal
	address (see <xref target="netaddr4"/> and <xref		address (see <xref target="netaddr4" format="default"/> and <xref target="
	target="RFC5665"/>), minus the netid, and either with		RFC5665" format="default"/>), minus the netid, and either with
	or without the trailing ".p1.p2" suffix that		or without the trailing ".p1.p2" suffix that
	represents the port number. If the suffix is omitted,		represents the port number. If the suffix is omitted,
	then the default port, 2049, SHOULD be assumed.		then the default port, 2049, <bcp14>SHOULD</bcp14> be assumed.
	A zero-length string SHOULD be used to indicate the current address		A zero-length string <bcp14>SHOULD</bcp14> be used to indicate the current address
	being used for the RPC call. It is not		being used for the RPC call. It is not
	a requirement that all servers that share the same rootpath		a requirement that all servers that share the same rootpath
	be listed		be listed
	in one fs_location4 instance. The array of server names is provided for		in one fs_location4 instance. The array of server names is provided for
	convenience. Servers that share the same rootpath may also be listed		convenience. Servers that share the same rootpath may also be listed
	in separate fs_location4 entries in the fs_locations attribute.		in separate fs_location4 entries in the fs_locations attribute.
	</t>		</t>
	<t>		<t>
	The fs_locations4 data type and the fs_locations attribute each		The fs_locations4 data type and the fs_locations attribute each
	contain an array of		contain an array of
	such locations. Since the namespace of each server may be		such locations. Since the namespace of each server may be
	constructed differently, the "fs_root" field is provided. The		constructed differently, the "fs_root" field is provided. The
	path represented		path represented
	by fs_root represents the location of the file system in the		by fs_root represents the location of the file system in the
	current server's namespace, i.e., that of the		current server's namespace, i.e., that of the
	server from which the fs_locations attribute was obtained. The		server from which the fs_locations attribute was obtained. The
	fs_root path is meant to aid the client by clearly referencing		fs_root path is meant to aid the client by clearly referencing
	the root of the file system whose locations are being reported,		the root of the file system whose locations are being reported,
	no matter what object within the current file system the		no matter what object within the current file system the
	current filehandle designates. The fs_root is simply the		current filehandle designates. The fs_root is simply the
	pathname the client used to reach the object on the current server		pathname the client used to reach the object on the current server
	(i.e., the object to which the fs_locations attribute applies).		(i.e., the object to which the fs_locations attribute applies).
	</t>		</t>
	<t>		<t>
	When the fs_locations attribute		When the fs_locations attribute
	is interrogated and there are no alternate file system locations,		is interrogated and there are no alternate file system locations,
	the server SHOULD return a zero-length array of fs_location4		the server <bcp14>SHOULD</bcp14> return a zero-length array of fs_location4
	structures, together with a valid fs_root.		structures, together with a valid fs_root.
	</t>		</t>
	<t>		<t>
	As an example, suppose there is a replicated file system located		As an example, suppose there is a replicated file system located
	at two		at two
	servers (servA and servB). At servA, the file system is located at		servers (servA and servB). At servA, the file system is located at
	path /a/b/c. At, servB the file system is located at path /x/y/z.		path /a/b/c. At, servB the file system is located at path /x/y/z.
	If the client were to obtain the fs_locations value for the		If the client were to obtain the fs_locations value for the
	directory at /a/b/c/d, it might not necessarily know		directory at /a/b/c/d, it might not necessarily know
	that the file system's root is located in servA's namespace		that the file system's root is located in servA's namespace
	at /a/b/c. When the client switches to servB, it will need		at /a/b/c. When the client switches to servB, it will need
	to determine that the directory it first referenced at servA is now		to determine that the directory it first referenced at servA is now
	represented by the path /x/y/z/d on servB. To facilitate this, the		represented by the path /x/y/z/d on servB. To facilitate this, the
	fs_locations attribute provided by servA would have an fs_root value		fs_locations attribute provided by servA would have an fs_root value
	of /a/b/c and two entries in fs_locations. One entry in fs_locations		of /a/b/c and two entries in fs_locations. One entry in fs_locations
	will be for itself (servA) and the other will be for servB with a		will be for itself (servA) and the other will be for servB with a
	path of /x/y/z. With this information, the client is able to		path of /x/y/z. With this information, the client is able to
	substitute /x/y/z for the /a/b/c at the beginning of its access		substitute /x/y/z for the /a/b/c at the beginning of its access
	path and construct /x/y/z/d to use for the new server.		path and construct /x/y/z/d to use for the new server.
	</t>		</t>
	<t>		<t>
	Note that there is no requirement that the number		Note that there is no requirement that the number
	of components in each rootpath be the same; there		of components in each rootpath be the same; there
	is no relation between the number of components in		is no relation between the number of components in
	rootpath or fs_root, and none of the components		rootpath or fs_root, and none of the components
	in a rootpath and fs_root have to be the same. In		in a rootpath and fs_root have to be the same. In
	the above example, we could have had a third element		the above example, we could have had a third element
	in the locations array, with server equal to "servC"		in the locations array, with server equal to "servC"
	and rootpath equal to "/I/II", and a fourth element in		and rootpath equal to "/I/II", and a fourth element in
	locations with server equal to "servD" and rootpath		locations with server equal to "servD" and rootpath
	equal to "/aleph/beth/gimel/daleth/he".		equal to "/aleph/beth/gimel/daleth/he".
	</t>		</t>
	<t>		<t>
	The relationship between fs_root to a rootpath is		The relationship between fs_root to a rootpath is
	that the client replaces the pathname indicated in		that the client replaces the pathname indicated in
	fs_root for the current server for the substitute		fs_root for the current server for the substitute
	indicated in rootpath for the new server.		indicated in rootpath for the new server.
	</t>		</t>
	<t>		<t>
	For an example of a referred or migrated file		For an example of a referred or migrated file
	system, suppose there is a file system located		system, suppose there is a file system located
	at serv1. At serv1, the file system is located at		at serv1. At serv1, the file system is located at
	/az/buky/vedi/glagoli. The client finds that object		/az/buky/vedi/glagoli. The client finds that object
	at glagoli has migrated (or is a referral). The		at glagoli has migrated (or is a referral). The
	client gets the fs_locations attribute, which contains		client gets the fs_locations attribute, which contains
	an fs_root of /az/buky/vedi/glagoli, and one element		an fs_root of /az/buky/vedi/glagoli, and one element
	in the locations array, with server equal to serv2,		in the locations array, with server equal to serv2,
	and rootpath equal to /izhitsa/fita. The client		and rootpath equal to /izhitsa/fita. The client
	replaces /az/buky/vedi/glagoli with /izhitsa/fita,		replaces /az/buky/vedi/glagoli with /izhitsa/fita,
	and uses the latter pathname on serv2.		and uses the latter pathname on serv2.
	</t>		</t>
			<t>
	<t>		Thus, the server <bcp14>MUST</bcp14> return an fs_root that is equal
	Thus, the server MUST return an fs_root that is equal
	to the path the client used to reach the object to which the		to the path the client used to reach the object to which the
	fs_locations attribute applies. Otherwise, the		fs_locations attribute applies. Otherwise, the
	client cannot determine the new path to use on the new server.		client cannot determine the new path to use on the new server.
	</t>		</t>
	<t>		<t>
	Since the fs_locations attribute lacks information defining various		Since the fs_locations attribute lacks information defining various
	attributes of the various file system choices presented, it SHOULD		attributes of the various file system choices presented, it <bcp14>SHOULD</ bcp14>
	only be interrogated and used when fs_locations_info is not available.		only be interrogated and used when fs_locations_info is not available.
	When fs_locations is used, information about the		When fs_locations is used, information about the
	specific locations should be assumed based on the following rules.		specific locations should be assumed based on the following rules.
	</t>		</t>
	<t>		<t>
	The following rules are general and apply irrespective of the		The following rules are general and apply irrespective of the
	context.		context.
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	All listed		All listed
	file system instances should be considered as of the		file system instances should be considered as of the
	same handle class, if and only if, the		same handle class, if and only if, the
	current fh_expire_type attribute does not include the		current fh_expire_type attribute does not include the
	FH4_VOL_MIGRATION		FH4_VOL_MIGRATION
	bit. Note that in the case of referral, filehandle issues do		bit. Note that in the case of referral, filehandle issues do
	not apply since there can be no filehandles known within the		not apply since there can be no filehandles known within the
	current file system, nor is there any access to the fh_expire_type		current file system, nor is there any access to the fh_expire_type
	attribute on the referring (absent) file system.		attribute on the referring (absent) file system.
	</t>		</li>
	<t>		<li>
	All listed file system instances should be considered as of the		All listed file system instances should be considered as of the
	same fileid class if and only if the		same fileid class if and only if the
	fh_expire_type attribute indicates persistent filehandles and		fh_expire_type attribute indicates persistent filehandles and
	does not include the FH4_VOL_MIGRATION		does not include the FH4_VOL_MIGRATION
	bit. Note that in the case of referral, fileid issues do		bit. Note that in the case of referral, fileid issues do
	not apply since there can be no fileids known within the		not apply since there can be no fileids known within the
	referring (absent) file system, nor is there any access to		referring (absent) file system, nor is there any access to
	the fh_expire_type attribute.		the fh_expire_type attribute.
	</t>		</li>
	<t>		<li>
	All file system instances		All file system instances
	servers should be considered as of different		servers should be considered as of different
	change classes.		change classes.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	For other class assignments, handling of file system		For other class assignments, handling of file system
	transitions depends on the reasons for the transition:		transitions depends on the reasons for the transition:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	When the transition is due to migration, that is, the client was		When the transition is due to migration, that is, the client was
	directed to a new file system after receiving an NFS4ERR_MOVED error,		directed to a new file system after receiving an NFS4ERR_MOVED error,
	the target should be		the target should be
	treated as being of the same		treated as being of the same
	write-verifier class as the source.		write-verifier class as the source.
	</t>		</li>
	<t>		<li>
	When the transition is due to failover to another replica,		When the transition is due to failover to another replica,
	that is, the client selected another replica without		that is, the client selected another replica without
	receiving an NFS4ERR_MOVED error, the target should be		receiving an NFS4ERR_MOVED error, the target should be
	treated as being of a different		treated as being of a different
	write-verifier class from the source.		write-verifier class from the source.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The specific choices reflect typical implementation patterns for		The specific choices reflect typical implementation patterns for
	failover and controlled migration, respectively. Since other		failover and controlled migration, respectively. Since other
	choices are possible and useful, this information is better		choices are possible and useful, this information is better
	obtained by using fs_locations_info. When a server implementation		obtained by using fs_locations_info. When a server implementation
	needs to communicate other choices, it MUST support the		needs to communicate other choices, it <bcp14>MUST</bcp14> support the
	fs_locations_info attribute.		fs_locations_info attribute.
	</t>		</t>
	<t>		<t>
	See <xref target="SECCON" /> for a		See <xref target="SECCON" format="default"/> for a
	discussion on the recommendations for the security		discussion on the recommendations for the security
	flavor to be used by any GETATTR operation that		flavor to be used by any GETATTR operation that
	requests the "fs_locations" attribute.		requests the fs_locations attribute.
	</t>		</t>
	</section>		</section>
	<section title="The Attribute fs_locations_info"		<section anchor="SEC11-li-new" numbered="true" toc="default">
	anchor="SEC11-li-new">		<name>The Attribute fs_locations_info</name>
	<t>		<t>
	The fs_locations_info attribute is intended as a more functional		The fs_locations_info attribute is intended as a more functional
	replacement for the fs_locations attribute which will continue to exist		replacement for the fs_locations attribute, which will continue to exist
	and be		and be supported. Clients can use it to get a more complete set of
	supported. Clients can use it to get a more complete set of
	data about alternative file system locations, including additional		data about alternative file system locations, including additional
	network paths to access replicas in use and additional replicas.		network paths to access replicas in use and additional replicas.
	When the server does not support		When the server does not support
	fs_locations_info, fs_locations can be used to get a subset of the		fs_locations_info, fs_locations can be used to get a subset of the
	data. A server that supports fs_locations_info MUST support		data. A server that supports fs_locations_info <bcp14>MUST</bcp14> suppor t
	fs_locations as well.		fs_locations as well.
	</t>		</t>
	<t>		<t>
	There is additional data present in		There is additional data present in
	fs_locations_info, that is not available in fs_locations:		fs_locations_info that is not available in fs_locations:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	Attribute continuity information. This information		Attribute continuity information. This information
	will allow a client to select a		will allow a client to select a
	replica that meets the transparency requirements of the		replica that meets the transparency requirements of the
	applications accessing the data and to leverage		applications accessing the data and to leverage
	optimizations due to the server guarantees of attribute		optimizations due to the server guarantees of attribute
	continuity (e.g., if the		continuity (e.g., if the
	change attribute of a file of the file system is continuous		change attribute of a file of the file system is continuous
	between multiple replicas,		between multiple replicas,
	the client does not have to invalidate the file's cache		the client does not have to invalidate the file's cache
	when switching to a different replica).		when switching to a different replica).
	</t>		</li>
	<t>		<li>
			<t>
	File system identity information that indicates when multiple		File system identity information that indicates when multiple
	replicas, from the client's point of view, correspond to the		replicas, from the client's point of view, correspond to the
	same target file system, allowing them to be used		same target file system, allowing them to be used
	interchangeably, without disruption, as distinct synchronized		interchangeably, without disruption, as distinct synchronized
	replicas of the same file data.		replicas of the same file data.
	<vspace blankLines="1"/>		</t>
			<t>
	Note that having two replicas with common identity information is		Note that having two replicas with common identity information is
	distinct from the case of two (trunked) paths to the same		distinct from the case of two (trunked) paths to the same
	replica.		replica.
	</t>		</t>
	<t>		</li>
			<li>
	Information that will bear on the suitability of various		Information that will bear on the suitability of various
	replicas, depending on the use that the client intends. For		replicas, depending on the use that the client intends. For
	example, many applications need an absolutely up-to-date copy		example, many applications need an absolutely up-to-date copy
	(e.g., those that write), while others may only need access to		(e.g., those that write), while others may only need access to
	the most up-to-date copy reasonably available.		the most up-to-date copy reasonably available.
	</t>		</li>
	<t>		<li>
	Server-derived preference information for replicas, which can		Server-derived preference information for replicas, which can
	be used to implement load-balancing while giving the client		be used to implement load-balancing while giving the client
	the entire file system list to be used in case the primary fails.		the entire file system list to be used in case the primary fails.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The fs_locations_info attribute is structured similarly to the		The fs_locations_info attribute is structured similarly to the
	fs_locations attribute. A top-level structure		fs_locations attribute. A top-level structure
	(fs_locations_info4) contains the entire attribute including the root		(fs_locations_info4) contains the entire attribute including the root
	pathname of the file system and an array of lower-level structures that		pathname of the file system and an array of lower-level structures that
	define replicas that share a common rootpath on their respective		define replicas that share a common rootpath on their respective
	servers. The lower-level structure in turn		servers. The lower-level structure in turn
	(fs_locations_item4) contains a specific pathname and information on one		(fs_locations_item4) contains a specific pathname and information on one
	or more individual network access paths. For that last lowest level,		or more individual network access paths. For that last, lowest level,
	fs_locations_info has an fs_locations_server4		fs_locations_info has an fs_locations_server4
	structure that contains per-server-replica information in addition		structure that contains per-server-replica information in addition
	to the file system		to the file system
	location entry. This per-server-replica information includes a		location entry. This per-server-replica information includes a
	nominally opaque array, fls_info, within which specific pieces		nominally opaque array, fls_info, within which specific pieces
	of information		of information are located at the specific indices listed below.
	are located at the specific indices listed below.		</t>
	</t>		<t>
	<t>
	Two fs_location_server4 entries that are within different		Two fs_location_server4 entries that are within different
	fs_location_item4 structures are never trunkable, while two entries		fs_location_item4 structures are never trunkable, while two entries
	within in the same fs_location_item4 structure might or might not be		within in the same fs_location_item4 structure might or might not be
	trunkable. Two entries that are trunkable will have identical		trunkable. Two entries that are trunkable will have identical
	identity information, although, as noted above, the converse is		identity information, although, as noted above, the converse is
	not the case.		not the case.
	</t>		</t>
	<t>		<t>
	The attribute will always contain at least a single fs_locations_server		The attribute will always contain at least a single fs_locations_server
	entry. Typically, there will be an entry with the FS4LIGF_CUR_REQ		entry. Typically, there will be an entry with the FS4LIGF_CUR_REQ
	flag set, although in the case of a referral there will be no		flag set, although in the case of a referral there will be no
	entry with that flag set.		entry with that flag set.
	</t>		</t>
	<t>		<t>
	It should be noted that fs_locations_info attributes returned by		It should be noted that fs_locations_info attributes returned by
	servers for various replicas may differ for various reasons.		servers for various replicas may differ for various reasons.
	One server may know about a set of replicas that are not known to		One server may know about a set of replicas that are not known to
	other servers. Further, compatibility attributes may differ.		other servers. Further, compatibility attributes may differ.
	Filehandles might be of the same class going from replica A to		Filehandles might be of the same class going from replica A to
	replica B but not going in the reverse direction. This might happen		replica B but not going in the reverse direction. This might happen
	because the filehandles are the same, but		because the filehandles are the same, but
	replica B's server implementation might not have provision to note		replica B's server implementation might not have provision to note
	and report that equivalence.		and report that equivalence.
	</t>		</t>
	<t>		<t>
	The fs_locations_info attribute consists of a root		The fs_locations_info attribute consists of a root
	pathname (fli_fs_root, just like fs_root in the		pathname (fli_fs_root, just like fs_root in the
	fs_locations attribute), together with an array of		fs_locations attribute), together with an array of
	fs_location_item4 structures. The fs_location_item4		fs_location_item4 structures. The fs_location_item4
	structures in turn consist of a root pathname		structures in turn consist of a root pathname
	(fli_rootpath) together with an array (fli_entries)		(fli_rootpath) together with an array (fli_entries)
	of elements of data type fs_locations_server4,		of elements of data type fs_locations_server4,
	all defined as follows.		all defined as follows.
	</t>		</t>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	/*		/*
	* Defines an individual server access path		* Defines an individual server access path
	*/		*/
	struct fs_locations_server4 {		struct fs_locations_server4 {
	int32_t fls_currency;		int32_t fls_currency;
	opaque fls_info&lt;>;		opaque fls_info<>;
	utf8str_cis fls_server;		utf8str_cis fls_server;
	};		};
	/*		/*
	* Byte indices of items within		* Byte indices of items within
	* fls_info: flag fields, class numbers,		* fls_info: flag fields, class numbers,
	* bytes indicating ranks and orders.		* bytes indicating ranks and orders.
	*/		*/
	const FSLI4BX_GFLAGS = 0;		const FSLI4BX_GFLAGS = 0;
	const FSLI4BX_TFLAGS = 1;		const FSLI4BX_TFLAGS = 1;
	skipping to change at line 18528 ¶		skipping to change at line 18626 ¶
	*/		*/
	const FSLI4TF_RDMA = 0x01;		const FSLI4TF_RDMA = 0x01;
	/*		/*
	* Defines a set of replicas sharing		* Defines a set of replicas sharing
	* a common value of the rootpath		* a common value of the rootpath
	* within the corresponding		* within the corresponding
	* single-server namespaces.		* single-server namespaces.
	*/		*/
	struct fs_locations_item4 {		struct fs_locations_item4 {
	fs_locations_server4 fli_entries&lt;>;		fs_locations_server4 fli_entries<>;
	pathname4 fli_rootpath;		pathname4 fli_rootpath;
	};		};
	/*		/*
	* Defines the overall structure of		* Defines the overall structure of
	* the fs_locations_info attribute.		* the fs_locations_info attribute.
	*/		*/
	struct fs_locations_info4 {		struct fs_locations_info4 {
	uint32_t fli_flags;		uint32_t fli_flags;
	int32_t fli_valid_for;		int32_t fli_valid_for;
	pathname4 fli_fs_root;		pathname4 fli_fs_root;
	fs_locations_item4 fli_items&lt;>;		fs_locations_item4 fli_items<>;
	};		};
	/*		/*
	* Flag bits in fli_flags.		* Flag bits in fli_flags.
	*/		*/
	const FSLI4IF_VAR_SUB = 0x00000001;		const FSLI4IF_VAR_SUB = 0x00000001;
	typedef fs_locations_info4 fattr4_fs_locations_info;		typedef fs_locations_info4 fattr4_fs_locations_info;
			]]></sourcecode>
	</artwork>		<t>
	</figure>
	<t>
	As noted above, the fs_locations_info attribute, when supported, may		As noted above, the fs_locations_info attribute, when supported, may
	be requested of absent file systems without causing NFS4ERR_MOVED to		be requested of absent file systems without causing NFS4ERR_MOVED to
	be returned. It is generally expected that it will be available for		be returned. It is generally expected that it will be available for
	both present and absent file systems even if only a single		both present and absent file systems even if only a single
	fs_locations_server4 entry is present, designating the current (present)		fs_locations_server4 entry is present, designating the current (present)
	file system, or two fs_locations_server4 entries designating the		file system, or two fs_locations_server4 entries designating the
	previous location of an absent file system (the one just referenced) and i ts		previous location of an absent file system (the one just referenced) and i ts
	successor location. Servers are strongly urged to support this		successor location. Servers are strongly urged to support this
	attribute on all file systems if they support it on any file system.		attribute on all file systems if they support it on any file system.
	</t>		</t>
	<t>		<t>
	The data presented in the fs_locations_info attribute may be obtained		The data presented in the fs_locations_info attribute may be obtained
	by the server in any number of ways, including specification by		by the server in any number of ways, including specification by
	the administrator or by current protocols for transferring data		the administrator or by current protocols for transferring data
	among replicas and protocols not yet developed. NFSv4.1 only defines		among replicas and protocols not yet developed. NFSv4.1 only defines
	how this information is presented by the server to		how this information is presented by the server to
	the client.		the client.
	</t>		</t>
	<section anchor="SEC11-fsli-server"		<section anchor="SEC11-fsli-server" numbered="true" toc="default">
	title="The fs_locations_server4 Structure">		<name>The fs_locations_server4 Structure</name>
	<t>		<t>
	The fs_locations_server4 structure consists of the following items		The fs_locations_server4 structure consists of the following items
	in addition to the fls_server field which specifies a network		in addition to the fls_server field, which specifies a network
	address or set of addresses to be used to access the specified file		address or set of addresses to be used to access the specified file
	system. Note that both of these items (i.e., fls_currency and flinfo)		system. Note that both of these items (i.e., fls_currency and
			fls_info)
	specify attributes of the		specify attributes of the
	file system replica and should not be different when there are		file system replica and should not be different when there are
	multiple fs_locations_server4 structures for the same replica, each		multiple fs_locations_server4 structures, each
	specifying a network path to the chosen replica.		specifying a network path to the chosen replica, for the same
	</t>		replica.
	<t>		</t>
			<t>
	When these values are different in two fs_locations_server4 structures,		When these values are different in two fs_locations_server4 structures,
	a client has no basis for choosing one over the other and is best off		a client has no basis for choosing one over the other and is best off
	simply ignoring both entries, whether these entries apply to migration		simply ignoring both entries, whether these entries apply to migration
	replication or referral. When there are more than two such entries,		replication or referral. When there are more than two such entries,
	majority voting can be used to exclude a single erroneous entry from		majority voting can be used to exclude a single erroneous entry from
	consideration. In the case in which trunking information is provided		consideration. In the case in which trunking information is provided
	for a replica currently being accessed, the additional trunked addresses		for a replica currently being accessed, the additional trunked addresses
	can be ignored while access continues on the address currently being		can be ignored while access continues on the address currently being
	used, even if the entry corresponding to that path might be considered		used, even if the entry corresponding to that path might be considered
	invalid.		invalid.
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	An indication of how up-to-date the file system is (fls_currency) in		An indication of how up-to-date the file system is (fls_currency) in
	seconds. This value		seconds. This value
	is relative to the master copy. A negative		is relative to the master copy. A negative
	value indicates that the server is unable to give any		value indicates that the server is unable to give any
	reasonably useful value here. A value of zero indicates that the		reasonably useful value here. A value of zero indicates that the
	file system is the actual writable data or a reliably coherent		file system is the actual writable data or a reliably coherent
	and fully up-to-date copy. Positive values indicate how		and fully up-to-date copy. Positive values indicate how
	out-of-date this copy can normally be before it is considered for		out-of-date this copy can normally be before it is considered for
	update. Such a value is not a guarantee that such updates		update. Such a value is not a guarantee that such updates
	will always be performed on the required schedule but instead		will always be performed on the required schedule but instead
	serves as a hint about how far the copy of the data would be		serves as a hint about how far the copy of the data would be
	expected to be behind the most up-to-date copy.		expected to be behind the most up-to-date copy.
	</t>		</li>
	<t>		<li>
	A counted array of one-byte values (fls_info) containing		A counted array of one-byte values (fls_info) containing
	information about the particular file system instance. This		information about the particular file system instance. This
	data includes general flags, transport capability flags,		data includes general flags, transport capability flags,
	file system equivalence class information, and selection		file system equivalence class information, and selection
	priority information. The encoding will be discussed below.		priority information. The encoding will be discussed below.
	</t>		</li>
	<t>		<li>
	The server string (fls_server). For the case of the		The server string (fls_server). For the case of the
	replica currently		replica currently
	being accessed (via GETATTR), a zero-length string MAY be used to		being accessed (via GETATTR), a zero-length string <bcp14>MAY</bcp14> be used to
	indicate the current address being used for the RPC call.		indicate the current address being used for the RPC call.
	The fls_server field can also be an IPv4 or IPv6 address,		The fls_server field can also be an IPv4 or IPv6 address,
	formatted the same way as an IPv4 or IPv6 address in the "server"		formatted the same way as an IPv4 or IPv6 address in the "server"
	field of the fs_location4 data type (see		field of the fs_location4 data type (see
	<xref target="fs_locations"/>).		<xref target="fs_locations" format="default"/>).
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	With the exception of the transport-flag field (at offset		With the exception of the transport-flag field (at offset
	FSLI4BX_TFLAGS with the fls_info array), all of this data defined		FSLI4BX_TFLAGS with the fls_info array), all of this data defined
	in this specification applies		in this specification applies to the replica specified by the entry,
	to the replica specified by the entry, rather that the specific		rather than the specific network path used to access it.
	network path used to access it. The classification of data in		The classification of data in extensions to this data is discussed below
	extensions to this data is discussed below.		.
	</t>		</t>
	<t>		<t>
	Data within the fls_info array is in the form of 8-bit data items		Data within the fls_info array is in the form of 8-bit data items
	with constants giving the offsets within the array of various		with constants giving the offsets within the array of various
	values describing this particular file system instance.		values describing this particular file system instance.
	This style of		This style of
	definition was chosen, in preference to explicit XDR		definition was chosen, in preference to explicit XDR
	structure definitions for these values, for a number of		structure definitions for these values, for a number of
	reasons.		reasons.
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	The kinds of data in the fls_info array, representing flags,		The kinds of data in the fls_info array, representing flags,
	file system classes, and priorities among sets of file systems		file system classes, and priorities among sets of file systems
	representing the same data, are such that 8 bits provide		representing the same data, are such that 8 bits provide
	a quite acceptable range of values. Even where there might		a quite acceptable range of values. Even where there might
	be more than 256 such file system instances, having more than		be more than 256 such file system instances, having more than
	256 distinct classes or priorities is unlikely.		256 distinct classes or priorities is unlikely.
	</t>		</li>
	<t>		<li>
	Explicit definition of the various specific data items within		Explicit definition of the various specific data items within
	XDR would limit expandability in that any extension within		XDR would limit expandability in that any extension within
	would require yet another attribute,		would require yet another attribute,
	leading to specification and implementation clumsiness.		leading to specification and implementation clumsiness.
	In the context of the NFSv4 extension model in effect at the time		In the context of the NFSv4 extension model in effect at the time
	fs_locations_info was designed (i.e. that described in		fs_locations_info was designed (i.e., that which is described in
	RFC5661 <xref target="RFC5661"/>), this would necessitate a new minor		RFC 5661 <xref target="RFC5661" format="default"/>), this would
	version		necessitate a new minor version
	to effect any Standards Track extension to the data in in		to effect any Standards Track extension to the data in fls_info.
	fls_info.		</li>
	</t>		</ul>
	</list>		<t>
	</t>
	<t>
	The set of fls_info data is subject to expansion in a future minor		The set of fls_info data is subject to expansion in a future minor
	version, or in a Standards Track RFC, within the context of a single		version or in a Standards Track RFC within the context of a single
	minor version. The server SHOULD NOT send and the client MUST NOT		minor version. The server <bcp14>SHOULD NOT</bcp14> send and the
	use indices within the fls_info array or flag bits that are not		client <bcp14>MUST NOT</bcp14> use indices within the fls_info array
	defined in		or flag bits that are not defined in Standards Track RFCs.
	Standards Track RFCs.		</t>
	</t>		<t>
	<t>		In light of the new extension model defined in RFC 8178
	In light of the new extension model defined in RFC8178		<xref target="RFC8178" format="default"/>
	<xref target="RFC8178"/>
	and the fact that the individual items within fls_info are not		and the fact that the individual items within fls_info are not
	explicitly referenced in the XDR, the following practices should be		explicitly referenced in the XDR, the following practices should be
	followed when extending or otherwise changing the structure of		followed when extending or otherwise changing the structure of
	the data returned in fls_info within the scope of a single minor		the data returned in fls_info within the scope of a single minor
	version.		version:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	All extensions need to be described by Standards Track documents.		All extensions need to be described by Standards Track documents.
	There		There is no need for such documents to be marked as updating
	is no need for such documents to be marked as updating		RFC 5661 <xref target="RFC5661" format="default"/> or this document.
	RFC5661 <xref target="RFC5661"/> or this document.		</li>
	</t>		<li>
	<t>
	It needs to be made clear whether the information in any added data		It needs to be made clear whether the information in any added data
	items applies to the replica specified by the entry or to the specific		items applies to the replica specified by the entry or to the specific
	network paths specified in the entry.		network paths specified in the entry.
	</t>		</li>
	<t>		<li>
	There needs to be a reliable way defined to determine whether the		There needs to be a reliable way defined to determine whether the
	server is aware of the extension. This may be based on the		server is aware of the extension. This may be based on the
	length field of the fls_info array, but it is more flexible to		length field of the fls_info array, but it is more flexible to
	provide fs-scope or server-scope attributes to indicate what		provide fs-scope or server-scope attributes to indicate what
	extensions are provided.		extensions are provided.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	This encoding scheme can be adapted to the specification of		This encoding scheme can be adapted to the specification of
	multi-byte numeric values, even though none are currently		multi-byte numeric values, even though none are currently
	defined. If extensions are made via Standards Track RFCs,		defined. If extensions are made via Standards Track RFCs,
	multi-byte quantities will be encoded as a range of bytes		multi-byte quantities will be encoded as a range of bytes
	with a range of indices, with the byte interpreted in big-endian		with a range of indices, with the byte interpreted in big-endian
	byte order. Further, any such index assignments will be constrained		byte order. Further, any such index assignments will be constrained
	by the need for the relevant quantities not to		by the need for the relevant quantities not to
	cross XDR word boundaries.		cross XDR word boundaries.
	</t>		</t>
	<t>		<t>
	The fls_info array currently contains:		The fls_info array currently contains:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	Two 8-bit flag fields, one devoted to general file-system		Two 8-bit flag fields, one devoted to general file-system
	characteristics and a second reserved for transport-related		characteristics and a second reserved for transport-related
	capabilities.		capabilities.
	</t>		</li>
	<t>		<li>
	Six 8-bit class values that define various file system		Six 8-bit class values that define various file system
	equivalence classes as explained below.		equivalence classes as explained below.
	</t>		</li>
	<t>		<li>
	Four 8-bit priority values that govern file system selection		Four 8-bit priority values that govern file system selection
	as explained below.		as explained below.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The general file system characteristics flag (at byte index		The general file system characteristics flag (at byte index
	FSLI4BX_GFLAGS) has the following		FSLI4BX_GFLAGS) has the following
	bits defined within it:		bits defined within it:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	FSLI4GF_WRITABLE indicates that this file system target is writable,		FSLI4GF_WRITABLE indicates that this file system target is writable,
	allowing it to be selected by clients that may need to write		allowing it to be selected by clients that may need to write
	on this file system. When the current file system instance		on this file system. When the current file system instance
	is writable and is defined as of the same simultaneous use		is writable and is defined as of the same simultaneous use
	class (as specified by the value at index FSLI4BX_CLSIMUL)		class (as specified by the value at index FSLI4BX_CLSIMUL)
	to which the client was previously writing, then it must		to which the client was previously writing, then it must
	incorporate within its data any committed		incorporate within its data any committed
	write made on the source file system instance. See		write made on the source file system instance. See
	<xref target="SEC11-EFF-wv" />, which discusses		<xref target="SEC11-EFF-wv" format="default"/>, which discusses
	the write-verifier class. While there is no harm in not setting		the write-verifier class. While there is no harm in not setting
	this flag for a file system that turns out to be writable,		this flag for a file system that turns out to be writable,
	turning the flag on for a read-only file system can cause		turning the flag on for a read-only file system can cause
	problems for clients that select a migration or replication		problems for clients that select a migration or replication
	target based on the flag and then find themselves unable to write.		target based on the flag and then find themselves unable to write.
	</t>		</li>
	<t>		<li>
	FSLI4GF_CUR_REQ indicates that this replica is the one on which		FSLI4GF_CUR_REQ indicates that this replica is the one on which
	the request is being made. Only a single server entry may		the request is being made. Only a single server entry may
	have this flag set and, in the case of a referral, no entry		have this flag set and, in the case of a referral, no entry
	will have it set. Note that this flag might be set even if the		will have it set. Note that this flag might be set even if the
	request was made on a network access path different from any of		request was made on a network access path different from any of
	those specified in the current entry.		those specified in the current entry.
	</t>		</li>
	<t>		<li>
	FSLI4GF_ABSENT indicates that this entry corresponds to an absent		FSLI4GF_ABSENT indicates that this entry corresponds to an absent
	file system replica. It can only be set if FSLI4GF_CUR_REQ is set.		file system replica. It can only be set if FSLI4GF_CUR_REQ is set.
	When both such bits are set, it indicates that a file system		When both such bits are set, it indicates that a file system
	instance is not usable but that the information in the entry		instance is not usable but that the information in the entry
	can be used to determine the sorts of continuity available		can be used to determine the sorts of continuity available
	when switching from this replica to other possible replicas.		when switching from this replica to other possible replicas.
	Since this bit can only be true if FSLI4GF_CUR_REQ is true, the		Since this bit can only be true if FSLI4GF_CUR_REQ is true, the
	value could be determined using the fs_status attribute, but		value could be determined using the fs_status attribute, but
	the information is also made available here for the		the information is also made available here for the
	convenience of the client. An entry with this bit, since it		convenience of the client. An entry with this bit, since it
	represents a true file system (albeit absent), does not appear		represents a true file system (albeit absent), does not appear
	in the event of a referral, but only when a file system has		in the event of a referral, but only when a file system has
	been accessed at this location and has subsequently been migrated.		been accessed at this location and has subsequently been migrated.
	</t>		</li>
	<t>		<li>
			<t>
	FSLI4GF_GOING indicates that a replica, while still available,		FSLI4GF_GOING indicates that a replica, while still available,
	should not be used further. The client, if using it, should		should not be used further. The client, if using it, should
	make an orderly transfer to another file system instance as		make an orderly transfer to another file system instance as
	expeditiously as possible. It is expected that file systems		expeditiously as possible. It is expected that file systems
	going out of service will be announced as FSLI4GF_GOING some time		going out of service will be announced as FSLI4GF_GOING some time
	before the actual loss of service. It is also expected that the		before the actual loss of service. It is also expected that the
	fli_valid_for value		fli_valid_for value
	will be sufficiently small to allow clients to detect and act		will be sufficiently small to allow clients to detect and act
	on scheduled events, while large enough that the cost of the		on scheduled events, while large enough that the cost of the
	requests to fetch the fs_locations_info values will not be		requests to fetch the fs_locations_info values will not be
	excessive. Values on the order of ten minutes seem		excessive. Values on the order of ten minutes seem
	reasonable.		reasonable.
	<vspace blankLines='1' />		</t>
			<t>
	When this flag is seen as part of a transition into a new		When this flag is seen as part of a transition into a new
	file system, a client might choose to transfer immediately		file system, a client might choose to transfer immediately
	to another replica, or it may reference the current file system		to another replica, or it may reference the current file system
	and only transition when a migration event occurs. Similarly,		and only transition when a migration event occurs. Similarly,
	when this flag appears as a replica in the referral, clients		when this flag appears as a replica in the referral, clients
	would likely avoid being referred to this instance whenever		would likely avoid being referred to this instance whenever
	there is another choice.		there is another choice.
	<vspace blankLines='1' />		</t>
	This flag, like the other items within fls_info applies to the		<t>
	replica, rather than to a particular path to that replica. When		This flag, like the other items within fls_info, applies to the
	it appears, a transition to a new replica rather than to a		replica rather than to a particular path to that replica. When
			it appears, a transition to a new replica, rather than to a
	different path to the same replica, is indicated.		different path to the same replica, is indicated.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	FSLI4GF_SPLIT indicates that when a transition occurs from		FSLI4GF_SPLIT indicates that when a transition occurs from
	the current file system instance to this one, the replacement		the current file system instance to this one, the replacement
	may consist of multiple file systems. In this case, the		may consist of multiple file systems. In this case, the
	client has to be prepared for the possibility that objects		client has to be prepared for the possibility that objects
	on the same file system before migration will be on different ones		on the same file system before migration will be on different ones
	after. Note that FSLI4GF_SPLIT is not incompatible with the		after. Note that FSLI4GF_SPLIT is not incompatible with the
	file systems belonging to the same fileid		file systems belonging to the same fileid
	class		class
	since, if one has a set of fileids that are unique within		since, if one has a set of fileids that are unique within
	a file system, each subset assigned to a smaller file system after mig ration		a file system, each subset assigned to a smaller file system after mig ration
	would not have any conflicts internal to that file system.		would not have any conflicts internal to that file system.
	<vspace blankLines='1' />		</t>
			<t>
	A client, in the case of a split file system, will interrogate		A client, in the case of a split file system, will interrogate
	existing files with which it has continuing connection (it		existing files with which it has continuing connection (it
	is free to simply forget cached filehandles). If the client		is free to simply forget cached filehandles). If the client
	remembers the directory filehandle associated with each open		remembers the directory filehandle associated with each open
	file, it may proceed upward using LOOKUPP to find the new file system		file, it may proceed upward using LOOKUPP to find the new file system
	boundaries. Note that in the event of a referral, there will		boundaries. Note that in the event of a referral, there will
	not be any such files and so these actions will not be performed.		not be any such files and so these actions will not be performed.
	Instead, a reference to a portion of the original		Instead, a reference to a portion of the original
	file system now split off into other file systems		file system now split off into other file systems
	will encounter an fsid change and possibly a		will encounter an fsid change and possibly a
	further referral.		further referral.
	<vspace blankLines='1' />		</t>
			<t>
	Once the client recognizes that one file system has been split		Once the client recognizes that one file system has been split
	into two, it can prevent the disruption of running applications		into two, it can prevent the disruption of running applications
	by presenting the two file systems as a single		by presenting the two file systems as a single
	one until a convenient point to recognize the transition,		one until a convenient point to recognize the transition,
	such as a restart. This would require a mapping		such as a restart. This would require a mapping
	from the server's fsids to fsids as seen by the client, but		from the server's fsids to fsids as seen by the client, but
	this is already necessary for other reasons. As noted		this is already necessary for other reasons. As noted
	above, existing fileids within the two descendant file systems		above, existing fileids within the two descendant file systems
	will not conflict. Providing non-conflicting fileids for		will not conflict. Providing non-conflicting fileids for
	newly created files on the split file systems		newly created files on the split file systems
	is the responsibility of the server (or servers working in		is the responsibility of the server (or servers working in
	concert). The server can encode filehandles such		concert). The server can encode filehandles such
	that filehandles generated before the split event can be discerned		that filehandles generated before the split event can be discerned
	from those generated after the split,		from those generated after the split,
	allowing the server to determine when the need		allowing the server to determine when the need
	for emulating two file systems as one is over.		for emulating two file systems as one is over.
	<vspace blankLines='1' />		</t>
			<t>
	Although it is possible for this flag to be present in the		Although it is possible for this flag to be present in the
	event of referral, it would generally be of little interest		event of referral, it would generally be of little interest
	to the client, since the client is not expected to have		to the client, since the client is not expected to have
	information regarding the current contents of the absent		information regarding the current contents of the absent
	file system.		file system.
	</t>		</t>
	</list>		</li>
	</t>		</ul>
	<t>		<t>
	The transport-flag field (at byte index FSLI4BX_TFLAGS) contains		The transport-flag field (at byte index FSLI4BX_TFLAGS) contains
	the following bits related to the transport		the following bits related to the transport
	capabilities of the specific network path(s) specified by the		capabilities of the specific network path(s) specified by the
	entry.		entry:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	FSLI4TF_RDMA indicates that any specified network paths		FSLI4TF_RDMA indicates that any specified network paths
	provide NFSv4.1 clients		provide NFSv4.1 clients
	access using an RDMA-capable transport.		access using an RDMA-capable transport.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Attribute continuity and file system identity information are		Attribute continuity and file system identity information are
	expressed by defining equivalence relations on the sets of		expressed by defining equivalence relations on the sets of
	file systems presented to the client. Each such relation		file systems presented to the client. Each such relation
	is expressed as a set of file system equivalence classes.		is expressed as a set of file system equivalence classes.
	For each relation, a file system has an 8-bit class number.		For each relation, a file system has an 8-bit class number.
	Two file systems belong to the same class if both have		Two file systems belong to the same class if both have
	identical non-zero class numbers. Zero is treated as		identical non-zero class numbers. Zero is treated as
	non-matching. Most often,		non-matching. Most often,
	the relevant question for the client will be whether a		the relevant question for the client will be whether a
	given replica is identical to / continuous with the current one in a		given replica is identical to / continuous with the current one in a
	given respect, but the information should be available also as to		given respect, but the information should be available also as to
	whether two other replicas match in that respect as well.		whether two other replicas match in that respect as well.
	</t>		</t>
	<t>		<t>
	The following fields specify the file system's class numbers		The following fields specify the file system's class numbers
	for the equivalence relations used in determining the nature of		for the equivalence relations used in determining the nature of
	file system transitions. See Sections		file system transitions. See Sections
	<xref target="SEC11-trans-oview" format="counter"/>		<xref target="SEC11-trans-oview" format="counter"/>
	through <xref target="SEC11-trans-server" format="counter"/>		through <xref target="SEC11-trans-server" format="counter"/>
	and their various subsections		and their various subsections
	for details about how		for details about how
	this information is to be used. Servers may assign these values		this information is to be used. Servers may assign these values
	as they wish, so long as file system instances that share the		as they wish, so long as file system instances that share the
	same value have the specified relationship to one another;		same value have the specified relationship to one another;
	conversely, file systems that have the specified relationship		conversely, file systems that have the specified relationship
	to one another share a common class value. As each instance		to one another share a common class value. As each instance
	entry is added, the relationships of this instance to previously		entry is added, the relationships of this instance to previously
	entered instances can be consulted, and if one is found that		entered instances can be consulted, and if one is found that
	bears the specified relationship, that entry's class value can		bears the specified relationship, that entry's class value can
	be copied to the new entry. When no such previous entry exists,		be copied to the new entry. When no such previous entry exists,
	a new value for that byte index (not previously used) can be		a new value for that byte index (not previously used) can be
	selected, most likely by incrementing the value of the last class		selected, most likely by incrementing the value of the last class
	value assigned for that index.		value assigned for that index.
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	The field with byte index FSLI4BX_CLSIMUL defines the		The field with byte index FSLI4BX_CLSIMUL defines the
	simultaneous-use class for the file system.		simultaneous-use class for the file system.
	</t>		</li>
	<t>		<li>
	The field with byte index FSLI4BX_CLHANDLE defines the handle		The field with byte index FSLI4BX_CLHANDLE defines the handle
	class for the file system.		class for the file system.
	</t>		</li>
	<t>		<li>
	The field with byte index FSLI4BX_CLFILEID defines the fileid		The field with byte index FSLI4BX_CLFILEID defines the fileid
	class for the file system.		class for the file system.
	</t>		</li>
	<t>		<li>
	The field with byte index FSLI4BX_CLWRITEVER defines the		The field with byte index FSLI4BX_CLWRITEVER defines the
	write-verifier class for the file system.		write-verifier class for the file system.
	</t>		</li>
	<t>		<li>
	The field with byte index FSLI4BX_CLCHANGE defines the change		The field with byte index FSLI4BX_CLCHANGE defines the change
	class for the file system.		class for the file system.
	</t>		</li>
	<t>		<li>
	The field with byte index FSLI4BX_CLREADDIR defines the readdir		The field with byte index FSLI4BX_CLREADDIR defines the readdir
	class for the file system.		class for the file system.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Server-specified preference information is also provided via		Server-specified preference information is also provided via
	8-bit values within the fls_info array. The values provide a		8-bit values within the fls_info array. The values provide a
	rank and an order (see below) to be used with separate values		rank and an order (see below) to be used with separate values
	specifiable for the cases of read-only and writable file		specifiable for the cases of read-only and writable file
	systems.		systems.
	These values are compared		These values are compared
	for different file systems to establish the server-specified		for different file systems to establish the server-specified
	preference, with lower values indicating "more preferred".		preference, with lower values indicating "more preferred".
	</t>		</t>
	<t>		<t>
	Rank is used to express a strict server-imposed ordering on		Rank is used to express a strict server-imposed ordering on
	clients, with lower values indicating "more preferred". Clients		clients, with lower values indicating "more preferred". Clients
	should attempt to use all replicas with a given rank before they		should attempt to use all replicas with a given rank before they
	use one with a higher rank. Only if all of those file systems are		use one with a higher rank. Only if all of those file systems are
	unavailable should the client proceed to those of a higher rank.		unavailable should the client proceed to those of a higher rank.
	Because specifying a rank will override client preferences, servers		Because specifying a rank will override client preferences, servers
	should be conservative about using this mechanism, particularly		should be conservative about using this mechanism, particularly
	when the environment is one in which client communication characteristic s		when the environment is one in which client communication characteristic s
	are neither tightly controlled nor visible to the server.		are neither tightly controlled nor visible to the server.
	</t>		</t>
	<t>		<t>
	Within a rank, the order value is used to specify the server's		Within a rank, the order value is used to specify the server's
	preference to guide the client's selection when the client's own		preference to guide the client's selection when the client's own
	preferences are not controlling, with lower values of order		preferences are not controlling, with lower values of order
	indicating "more preferred". If replicas are approximately equal		indicating "more preferred". If replicas are approximately equal
	in all respects, clients should defer to the order specified by the		in all respects, clients should defer to the order specified by the
	server. When clients look at server latency as part of their		server. When clients look at server latency as part of their
	selection, they are free to use this criterion, but it is suggested		selection, they are free to use this criterion, but it is suggested
	that when latency differences are not significant, the		that when latency differences are not significant, the
	server-specified order should guide selection.		server-specified order should guide selection.
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	The field at byte index FSLI4BX_READRANK gives the rank value to		The field at byte index FSLI4BX_READRANK gives the rank value to
	be used for read-only access.		be used for read-only access.
	</t>		</li>
	<t>		<li>
	The field at byte index FSLI4BX_READORDER gives the order value to		The field at byte index FSLI4BX_READORDER gives the order value to
	be used for read-only access.		be used for read-only access.
	</t>		</li>
	<t>		<li>
	The field at byte index FSLI4BX_WRITERANK gives the rank value to		The field at byte index FSLI4BX_WRITERANK gives the rank value to
	be used for writable access.		be used for writable access.
	</t>		</li>
	<t>		<li>
	The field at byte index FSLI4BX_WRITEORDER gives the order value to		The field at byte index FSLI4BX_WRITEORDER gives the order value to
	be used for writable access.		be used for writable access.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Depending on the potential need for write access by a given client,		Depending on the potential need for write access by a given client,
	one of the pairs of rank and order values is used.		one of the pairs of rank and order values is used.
	The read rank and order should only be used		The read rank and order should only be used
	if the client knows that only reading will ever be done or if it is		if the client knows that only reading will ever be done or if it is
	prepared to switch to a different replica in the event that any		prepared to switch to a different replica in the event that any
	write access capability is required in the future.		write access capability is required in the future.
	</t>		</t>
	</section>		</section>
	<section anchor="SEC11-fsli-info"		<section anchor="SEC11-fsli-info" numbered="true" toc="default">
	title="The fs_locations_info4 Structure">		<name>The fs_locations_info4 Structure</name>
	<t>		<t>
	The fs_locations_info4 structure, encoding the fs_locations_info		The fs_locations_info4 structure, encoding the fs_locations_info
	attribute, contains the following:		attribute, contains the following:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	The fli_flags field, which contains general flags that affect		The fli_flags field, which contains general flags that affect
	the interpretation of this fs_locations_info4 structure and		the interpretation of this fs_locations_info4 structure and
	all fs_locations_item4 structures within it. The only flag		all fs_locations_item4 structures within it. The only flag
	currently defined is FSLI4IF_VAR_SUB. All bits in the		currently defined is FSLI4IF_VAR_SUB. All bits in the
	fli_flags field that are not defined should always be returned as zero.		fli_flags field that are not defined should always be returned as zero.
	</t>		</li>
	<t>		<li>
	The fli_fs_root field, which contains the pathname of the root of		The fli_fs_root field, which contains the pathname of the root of
	the current file system on the current server, just as it does		the current file system on the current server, just as it does
	in the fs_locations4 structure.		in the fs_locations4 structure.
	</t>		</li>
	<t>		<li>
	An array called fli_items of fs_locations4_item structures, which cont ain		An array called fli_items of fs_locations4_item structures, which cont ain
	information about replicas of the current file system. Where		information about replicas of the current file system. Where
	the current file system is actually present, or has been		the current file system is actually present, or has been
	present, i.e., this is not a referral situation, one of the		present, i.e., this is not a referral situation, one of the
	fs_locations_item4 structures will contain an fs_locations_server4 for		fs_locations_item4 structures will contain an fs_locations_server4 for
	the current server. This structure will have FSLI4GF_ABSENT set		the current server. This structure will have FSLI4GF_ABSENT set
	if the current file system is absent, i.e., normal access to it		if the current file system is absent, i.e., normal access to it
	will return NFS4ERR_MOVED.		will return NFS4ERR_MOVED.
	</t>		</li>
	<t>		<li>
	The fli_valid_for field specifies a time in seconds		The fli_valid_for field specifies a time in seconds
	for which it is reasonable for a client to use the fs_locations_info a ttribute		for which it is reasonable for a client to use the fs_locations_info a ttribute
	without refetch. The fli_valid_for value does not provide a		without refetch. The fli_valid_for value does not provide a
	guarantee of validity since servers can unexpectedly go out of		guarantee of validity since servers can unexpectedly go out of
	service or become inaccessible for any number of reasons.		service or become inaccessible for any number of reasons.
	Clients are well-advised to refetch this information for an		Clients are well-advised to refetch this information for an
	actively accessed file system at every fli_valid_for seconds. This		actively accessed file system at every fli_valid_for seconds. This
	is particularly important when file system replicas may go out		is particularly important when file system replicas may go out
	of service in a controlled way using the FSLI4GF_GOING flag to		of service in a controlled way using the FSLI4GF_GOING flag to
	communicate an ongoing change. The server should set		communicate an ongoing change. The server should set
	skipping to change at line 19061 ¶		skipping to change at line 19149 ¶
	different fli_valid_for value, which the client should then use		different fli_valid_for value, which the client should then use
	in the same fashion as the previous value. Because a refetch		in the same fashion as the previous value. Because a refetch
	of the attribute causes information from all component entries to		of the attribute causes information from all component entries to
	be refetched, the server will typically provide a low value for		be refetched, the server will typically provide a low value for
	this field if any of the replicas are likely to go out of service		this field if any of the replicas are likely to go out of service
	in a short time frame. Note that, because of the ability of the		in a short time frame. Note that, because of the ability of the
	server to return NFS4ERR_MOVED to trigger the use of different paths,		server to return NFS4ERR_MOVED to trigger the use of different paths,
	when alternate trunked paths are available, there is generally no		when alternate trunked paths are available, there is generally no
	need to use low values of fli_valid_for in connection with the		need to use low values of fli_valid_for in connection with the
	management of alternate paths to the same replica.		management of alternate paths to the same replica.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The FSLI4IF_VAR_SUB flag within fli_flags controls whether variable		The FSLI4IF_VAR_SUB flag within fli_flags controls whether variable
	substitution is to be enabled. See <xref target="SEC11-fsli-item" />		substitution is to be enabled. See <xref target="SEC11-fsli-item" forma t="default"/>
	for an explanation of variable substitution.		for an explanation of variable substitution.
	</t>		</t>
	</section>		</section>
	<section anchor="SEC11-fsli-item"		<section anchor="SEC11-fsli-item" numbered="true" toc="default">
	title="The fs_locations_item4 Structure">		<name>The fs_locations_item4 Structure</name>
	<t>		<t>
	The fs_locations_item4 structure contains a pathname		The fs_locations_item4 structure contains a pathname
	(in the field fli_rootpath) that encodes		(in the field fli_rootpath) that encodes
	the path of the target file system replicas on the set of		the path of the target file system replicas on the set of
	servers designated by the included fs_locations_server4 entries.		servers designated by the included fs_locations_server4 entries.
	The precise manner in which this target location		The precise manner in which this target location
	is specified depends on the value of the FSLI4IF_VAR_SUB		is specified depends on the value of the FSLI4IF_VAR_SUB
	flag within the associated fs_locations_info4 structure.		flag within the associated fs_locations_info4 structure.
	</t>		</t>
	<t>		<t>
	If this flag is not set, then fli_rootpath simply designates		If this flag is not set, then fli_rootpath simply designates
	the location of the target file system within each server's		the location of the target file system within each server's
	single-server namespace just as it does for the rootpath		single-server namespace just as it does for the rootpath
	within the fs_location4 structure. When this bit is set,		within the fs_location4 structure. When this bit is set,
	however, component entries of a certain form are subject		however, component entries of a certain form are subject
	to client-specific variable substitution so as to allow		to client-specific variable substitution so as to allow
	a degree of namespace non-uniformity in order to accommodate		a degree of namespace non-uniformity in order to accommodate
	the selection of client-specific file system targets to		the selection of client-specific file system targets to
	adapt to different client architectures or other		adapt to different client architectures or other
	characteristics.		characteristics.
	</t>		</t>
	<t>		<t>
	When such substitution is in effect, a variable beginning		When such substitution is in effect, a variable beginning
	with the string "${" and ending with the string "}"		with the string "${" and ending with the string "}"
	and containing a colon is to be		and containing a colon is to be
	replaced by the client-specific value associated with		replaced by the client-specific value associated with
	that variable. The string "unknown" should be used		that variable. The string "unknown" should be used
	by the client when it has no value for such a variable.		by the client when it has no value for such a variable.
	The pathname resulting from such		The pathname resulting from such
	substitutions is used to designate the target file system,		substitutions is used to designate the target file system,
	so that different clients may have different file systems,		so that different clients may have different file systems,
	corresponding to that location in the multi-server namespace.		corresponding to that location in the multi-server namespace.
	</t>		</t>
	<t>		<t>
	As mentioned above, such substituted pathname variables		As mentioned above, such substituted pathname variables
	contain a colon. The part before the colon is to be a		contain a colon. The part before the colon is to be a
	DNS domain name, and the part after is to be a case-insensitive		DNS domain name, and the part after is to be a case-insensitive
	alphanumeric string.		alphanumeric string.
	</t>		</t>
	<t>		<t>
	Where the domain is "ietf.org", only variable names defined		Where the domain is "ietf.org", only variable names defined
	in this document or subsequent Standards Track RFCs		in this document or subsequent Standards Track RFCs
	are subject to such substitution. Organizations are		are subject to such substitution. Organizations are
	free to use their domain names to create their own sets		free to use their domain names to create their own sets
	of client-specific variables, to be subject to such		of client-specific variables, to be subject to such
	substitution. In cases where such variables are intended		substitution. In cases where such variables are intended
	to be used more broadly than a single organization,		to be used more broadly than a single organization,
	publication of an Informational RFC defining such variables		publication of an Informational RFC defining such variables
	is RECOMMENDED.		is <bcp14>RECOMMENDED</bcp14>.
	</t>		</t>
	<t>		<t>
	The variable ${ietf.org:CPU_ARCH} is used to denote that the		The variable ${ietf.org:CPU_ARCH} is used to denote that the
	CPU architecture object files are compiled. This specification		CPU architecture object files are compiled. This specification
	does not limit the acceptable values (except that they must be		does not limit the acceptable values (except that they must be
	valid UTF-8 strings), but such values as "x86", "x86_64", and "sparc"		valid UTF-8 strings), but such values as "x86", "x86_64", and "sparc"
	would be expected to be used in line with industry practice.		would be expected to be used in line with industry practice.
	</t>		</t>
	<t>		<t>
	The variable ${ietf.org:OS_TYPE} is used to denote the		The variable ${ietf.org:OS_TYPE} is used to denote the
	operating system, and thus the kernel and library APIs,		operating system, and thus the kernel and library APIs,
	for which code might be compiled. This specification does		for which code might be compiled. This specification does
	not limit the acceptable values (except that they must be		not limit the acceptable values (except that they must be
	valid UTF-8 strings), but such values as "linux" and "freebsd"		valid UTF-8 strings), but such values as "linux" and "freebsd"
	would be expected to be used in line with industry practice.		would be expected to be used in line with industry practice.
	</t>		</t>
	<t>		<t>
	The variable ${ietf.org:OS_VERSION} is used to denote the		The variable ${ietf.org:OS_VERSION} is used to denote the
	operating system version, and thus the specific details		operating system version, and thus the specific details
	of versioned interfaces,		of versioned interfaces,
	for which code might be compiled. This specification does		for which code might be compiled. This specification does
	not limit the acceptable values (except that they must be		not limit the acceptable values (except that they must be
	valid UTF-8 strings). However, combinations of numbers and		valid UTF-8 strings). However, combinations of numbers and
	letters with interspersed dots would be expected to be used		letters with interspersed dots would be expected to be used
	in line with industry practice, with the details of the		in line with industry practice, with the details of the
	version format depending on the specific value of		version format depending on the specific value of
	the variable ${ietf.org:OS_TYPE} with which		the variable ${ietf.org:OS_TYPE} with which
	it is used.		it is used.
	</t>		</t>
	<t>		<t>
	Use of these variables could result in the direction of different		Use of these variables could result in the direction of different
	clients to different file systems on the same server, as		clients to different file systems on the same server, as
	appropriate to particular clients. In cases in which the		appropriate to particular clients. In cases in which the
	target file systems are located on different servers, a single		target file systems are located on different servers, a single
	server could serve as a referral point so that each valid		server could serve as a referral point so that each valid
	combination of variable values would designate a referral		combination of variable values would designate a referral
	hosted on a single server, with the targets of those referrals on		hosted on a single server, with the targets of those referrals on
	a number of different servers.		a number of different servers.
	</t>		</t>
	<t>		<t>
	Because namespace administration is affected by the values		Because namespace administration is affected by the values
	selected to substitute for various variables, clients should		selected to substitute for various variables, clients should
	provide convenient means of determining what variable		provide convenient means of determining what variable
	substitutions a client will implement, as well as, where		substitutions a client will implement, as well as, where
	appropriate, providing means to control the substitutions to		appropriate, providing means to control the substitutions to
	be used. The exact means by which this will be done is		be used. The exact means by which this will be done is
	outside the scope of this specification.		outside the scope of this specification.
	</t>		</t>
	<t>		<t>
	Although variable substitution is most suitable for use		Although variable substitution is most suitable for use
	in the context of referrals, it may be used in the context		in the context of referrals, it may be used in the context
	of replication and migration. If it is used in these contexts,		of replication and migration. If it is used in these contexts,
	the server must ensure that no matter what values the		the server must ensure that no matter what values the
	client presents for the substituted variables, the result		client presents for the substituted variables, the result
	is always a valid successor file system instance to that		is always a valid successor file system instance to that
	from which a transition is occurring, i.e., that the data is		from which a transition is occurring, i.e., that the data is
	identical or represents a later image of a writable file		identical or represents a later image of a writable file
	system.		system.
	</t>		</t>
	<t>		<t>
	Note that when fli_rootpath is a null pathname (that is, one		Note that when fli_rootpath is a null pathname (that is, one
	with zero components), the file system designated is at the		with zero components), the file system designated is at the
	root of the specified server, whether or not the FSLI4IF_VAR_SUB		root of the specified server, whether or not the FSLI4IF_VAR_SUB
	flag within the associated fs_locations_info4 structure is		flag within the associated fs_locations_info4 structure is
	set.		set.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section anchor="fs_status"		<section anchor="fs_status" numbered="true" toc="default">
	title="The Attribute fs_status">		<name>The Attribute fs_status</name>
	<t>		<t>
	In an environment in which multiple copies of the same basic set of		In an environment in which multiple copies of the same basic set of
	data are available, information regarding the particular source of		data are available, information regarding the particular source of
	such data and the relationships among different copies can be very		such data and the relationships among different copies can be very
	helpful in providing consistent data to applications.		helpful in providing consistent data to applications.
	</t>		</t>
			<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	enum fs4_status_type {		enum fs4_status_type {
	STATUS4_FIXED = 1,		STATUS4_FIXED = 1,
	STATUS4_UPDATED = 2,		STATUS4_UPDATED = 2,
	STATUS4_VERSIONED = 3,		STATUS4_VERSIONED = 3,
	STATUS4_WRITABLE = 4,		STATUS4_WRITABLE = 4,
	STATUS4_REFERRAL = 5		STATUS4_REFERRAL = 5
	};		};
	struct fs4_status {		struct fs4_status {
	bool fss_absent;		bool fss_absent;
	fs4_status_type fss_type;		fs4_status_type fss_type;
	utf8str_cs fss_source;		utf8str_cs fss_source;
	utf8str_cs fss_current;		utf8str_cs fss_current;
	int32_t fss_age;		int32_t fss_age;
	nfstime4 fss_version;		nfstime4 fss_version;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The boolean fss_absent indicates whether the file system is		The boolean fss_absent indicates whether the file system is
	currently absent. This value will be set if the file system was		currently absent. This value will be set if the file system was
	previously present and becomes absent, or if the file system has		previously present and becomes absent, or if the file system has
	never been present and the type is STATUS4_REFERRAL. When this		never been present and the type is STATUS4_REFERRAL. When this
	boolean is set and the type is not STATUS4_REFERRAL, the		boolean is set and the type is not STATUS4_REFERRAL, the
	remaining information in the fs4_status reflects that last valid		remaining information in the fs4_status reflects that last valid
	when the file system was present.		when the file system was present.
	</t>		</t>
	<t>		<t>
	The fss_type field indicates the kind of file system image represented.		The fss_type field indicates the kind of file system image represented.
	This is of particular importance when using the version values to		This is of particular importance when using the version values to
	determine appropriate succession of file system images.		determine appropriate succession of file system images.
	When fss_absent is set, and the file system was previously		When fss_absent is set, and the file system was previously
	present, the value of fss_type reflected is that when the file was last pr esent.		present, the value of fss_type reflected is that when the file was last pr esent.
	Five values are distinguished:		Five values are distinguished:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style='symbols'>		<li>
	<t>
	STATUS4_FIXED, which indicates a read-only image in the sense		STATUS4_FIXED, which indicates a read-only image in the sense
	that it will never change. The possibility is allowed that, as		that it will never change. The possibility is allowed that, as
	a result of migration or switch to a different image, changed		a result of migration or switch to a different image, changed
	data can be accessed, but within the confines of this instance,		data can be accessed, but within the confines of this instance,
	no change is allowed. The client can use this fact to		no change is allowed. The client can use this fact to
	cache aggressively.		cache aggressively.
	</t>		</li>
	<t>		<li>
	STATUS4_VERSIONED, which indicates that the image, like the		STATUS4_VERSIONED, which indicates that the image, like the
	STATUS4_UPDATED case, is updated externally, but it provides		STATUS4_UPDATED case, is updated externally, but it provides
	a guarantee that the server will carefully update an		a guarantee that the server will carefully update an
	associated version value so that the client can		associated version value so that the client can
	protect itself from a situation in which it reads		protect itself from a situation in which it reads
	data from one version of the file system and then later reads		data from one version of the file system and then later reads
	data from an earlier version of the same file system. See		data from an earlier version of the same file system. See
	below for a discussion of how this can be done.		below for a discussion of how this can be done.
	</t>		</li>
	<t>		<li>
	STATUS4_UPDATED, which indicates an image that cannot be		STATUS4_UPDATED, which indicates an image that cannot be
	updated by the user writing to it but that may be changed		updated by the user writing to it but that may be changed
	externally, typically because it is a periodically updated		externally, typically because it is a periodically updated
	copy of another writable file system somewhere else. In		copy of another writable file system somewhere else. In
	this case, version information is not provided, and the		this case, version information is not provided, and the
	client does not have the responsibility of making sure		client does not have the responsibility of making sure
	that this version only advances upon a file system instance		that this version only advances upon a file system instance
	transition. In this case, it is the responsibility of the		transition. In this case, it is the responsibility of the
	server to make sure that the data presented after a file		server to make sure that the data presented after a file
	system instance transition is a proper successor image and		system instance transition is a proper successor image and
	includes all changes seen by the client and any change made		includes all changes seen by the client and any change made
	before all such changes.		before all such changes.
	</t>		</li>
	<t>		<li>
	STATUS4_WRITABLE, which indicates that the file system is an		STATUS4_WRITABLE, which indicates that the file system is an
	actual writable one. The client need not, of course, actually		actual writable one. The client need not, of course, actually
	write to the file system, but once it does, it should not		write to the file system, but once it does, it should not
	accept a transition to anything other than a writable instance		accept a transition to anything other than a writable instance
	of that same file system.		of that same file system.
	</t>		</li>
	<t>		<li>
	STATUS4_REFERRAL, which indicates that the file system in		STATUS4_REFERRAL, which indicates that the file system in
	question is absent and has never been present on this		question is absent and has never been present on this
	server.		server.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Note that in the STATUS4_UPDATED and STATUS4_VERSIONED cases, the		Note that in the STATUS4_UPDATED and STATUS4_VERSIONED cases, the
	server is responsible for the appropriate handling of locks that		server is responsible for the appropriate handling of locks that
	are inconsistent with external changes to delegations.		are inconsistent with external changes to delegations.
	If a server gives out delegations, they SHOULD be recalled		If a server gives out delegations, they <bcp14>SHOULD</bcp14> be recalled
	before an inconsistent change is made to the data, and MUST		before an inconsistent change is made to the data, and <bcp14>MUST</bcp14>
	be revoked if this is not possible. Similarly, if an OPEN is		be revoked if this is not possible. Similarly, if an OPEN is
	inconsistent with data that is changed (the OPEN has		inconsistent with data that is changed (the OPEN has
	OPEN4_SHARE_DENY_WRITE/OPEN4_SHARE_DENY_BOTH		OPEN4_SHARE_DENY_WRITE/OPEN4_SHARE_DENY_BOTH
	and the data is changed), that OPEN SHOULD be considered		and the data is changed), that OPEN <bcp14>SHOULD</bcp14> be considered
	administratively revoked.		administratively revoked.
	</t>		</t>
	<t>		<t>
	The opaque strings fss_source and fss_current provide a way of presenting		The opaque strings fss_source and fss_current provide a way of presenting
	information about the source of the file system image being present.		information about the source of the file system image being present.
	It is not intended that the client do anything with this information		It is not intended that the client do anything with this information
	other than make it available to administrative tools. It is		other than make it available to administrative tools. It is
	intended that this information be helpful when researching possible		intended that this information be helpful when researching possible
	problems with a file system image that might arise when it is		problems with a file system image that might arise when it is
	unclear if the correct image is being accessed and, if not, how that		unclear if the correct image is being accessed and, if not, how that
	image came to be made. This kind of diagnostic information will be		image came to be made. This kind of diagnostic information will be
	helpful, if, as seems likely, copies of file systems are made in		helpful, if, as seems likely, copies of file systems are made in
	many different ways (e.g., simple user-level copies,		many different ways (e.g., simple user-level copies,
	file-system-level point-in-time copies,		file-system-level point-in-time copies,
	clones of the underlying storage),		clones of the underlying storage),
	under a variety of administrative arrangements. In such		under a variety of administrative arrangements. In such
	environments, determining how a given set of data was constructed		environments, determining how a given set of data was constructed
	can be very helpful in resolving problems.		can be very helpful in resolving problems.
	</t>		</t>
	<t>		<t>
	The opaque string fss_source is used to indicate the source of a		The opaque string fss_source is used to indicate the source of a
	given file system with the expectation that tools capable of		given file system with the expectation that tools capable of
	creating a file system image propagate this information, when		creating a file system image propagate this information, when
	possible. It is understood that this may not always be possible		possible. It is understood that this may not always be possible
	since a user-level copy may be thought of as creating a new data		since a user-level copy may be thought of as creating a new data
	set and the tools used may have no mechanism to propagate this		set and the tools used may have no mechanism to propagate this
	data. When a file system is initially created, it is desirable		data. When a file system is initially created, it is desirable
	to associate with it		to associate with it
	data regarding how the file system was created, where it was		data regarding how the file system was created, where it was
	created, who created it, etc. Making this information available		created, who created it, etc. Making this information available
	in this attribute in a human-readable		in this attribute in a human-readable
	string will be helpful for applications and		string will be helpful for applications and
	system administrators and will also serve to make it available when		system administrators and will also serve to make it available when
	the original file system is used to make subsequent copies.		the original file system is used to make subsequent copies.
	</t>		</t>
	<t>		<t>
	The opaque string fss_current should provide whatever information is		The opaque string fss_current should provide whatever information is
	available about the source of the current copy. Such		available about the source of the current copy. Such
	information includes		information includes
	the tool creating it, any relevant parameters to that tool, the		the tool creating it, any relevant parameters to that tool, the
	time at which the copy was done, the user making the change, the		time at which the copy was done, the user making the change, the
	server on which the change was made, etc. All information should be		server on which the change was made, etc. All information should be
	in a human-readable string.		in a human-readable string.
	</t>		</t>
	<t>		<t>
	The field fss_age provides an indication of how out-of-date the file syste m		The field fss_age provides an indication of how out-of-date the file syste m
	currently is with respect to its ultimate data source (in case of		currently is with respect to its ultimate data source (in case of
	cascading data updates). This complements the fls_currency field of		cascading data updates). This complements the fls_currency field of
	fs_locations_server4 (see <xref target='SEC11-li-new' />) in the		fs_locations_server4 (see <xref target="SEC11-li-new" format="default"/>) in the
	following way: the information in fls_currency		following way: the information in fls_currency
	gives a bound for how out of date the data in a file system might		gives a bound for how out of date the data in a file system might
	typically get, while the value in fss_age gives a bound on how out-of-date that		typically get, while the value in fss_age gives a bound on how out-of-date that
	data actually is. Negative values imply that no information is		data actually is. Negative values imply that no information is
	available. A zero means that this data is known to be current.		available. A zero means that this data is known to be current.
	A positive value means that this data is known to be no older than		A positive value means that this data is known to be no older than
	that number of seconds with respect to the ultimate data source.		that number of seconds with respect to the ultimate data source.
	Using this value, the client may be able to decide that a data copy		Using this value, the client may be able to decide that a data copy
	is too old, so that it may search for a newer version to use.		is too old, so that it may search for a newer version to use.
	</t>		</t>
	<t>		<t>
	The fss_version field provides a version identification, in the form of		The fss_version field provides a version identification, in the form of
	a time value, such that successive versions always have later time		a time value, such that successive versions always have later time
	values. When the fs_type is anything other than		values. When the fs_type is anything other than
	STATUS4_VERSIONED, the server may provide such a value, but there is		STATUS4_VERSIONED, the server may provide such a value, but there is
	no guarantee as to its validity and clients will not use it except		no guarantee as to its validity and clients will not use it except
	to provide additional information to add to fss_source and fss_current.		to provide additional information to add to fss_source and fss_current.
	</t>		</t>
	<t>		<t>
	When fss_type is STATUS4_VERSIONED, servers SHOULD provide a value		When fss_type is STATUS4_VERSIONED, servers <bcp14>SHOULD</bcp14> provide
			a value
	of fss_version that progresses monotonically whenever any new version		of fss_version that progresses monotonically whenever any new version
	of the data is established. This allows the client, if reliable		of the data is established. This allows the client, if reliable
	image progression is important to it, to fetch this attribute as		image progression is important to it, to fetch this attribute as
	part of each COMPOUND where data or metadata from the file system is		part of each COMPOUND where data or metadata from the file system is
	used.		used.
	</t>		</t>
	<t>		<t>
	When it is important to the client to make sure that only valid		When it is important to the client to make sure that only valid
	successor images are accepted, it must make sure that it does not		successor images are accepted, it must make sure that it does not
	read data or metadata from the file system without updating its		read data or metadata from the file system without updating its
	sense of the current state of the image. This is to avoid the possibility		sense of the current state of the image. This is to avoid the possibility
	that the fs_status that the client holds will be one for an		that the fs_status that the client holds will be one for an
	earlier image, which would cause the client to accept a new file		earlier image, which would cause the client to accept a new file
	system instance that is later than that but still earlier than		system instance that is later than that but still earlier than
	the updated data read by the client.		the updated data read by the client.
	</t>		</t>
	<t>		<t>
	In order to accept valid images reliably, the client must do a GETATTR of the fs_status		In order to accept valid images reliably, the client must do a GETATTR of the fs_status
	attribute that follows any interrogation of data or metadata within the		attribute that follows any interrogation of data or metadata within the
	file system in question. Often this is most conveniently done by		file system in question. Often this is most conveniently done by
	appending such a GETATTR after all other operations that reference		appending such a GETATTR after all other operations that reference
	a given file system. When errors occur between reading file system		a given file system. When errors occur between reading file system
	data and performing such a GETATTR, care must be exercised to make		data and performing such a GETATTR, care must be exercised to make
	sure that the data in question is not used before obtaining the		sure that the data in question is not used before obtaining the
	proper fs_status value. In this connection, when an OPEN is done		proper fs_status value. In this connection, when an OPEN is done
	within such a versioned file system and the associated GETATTR of		within such a versioned file system and the associated GETATTR of
	fs_status is not successfully completed, the open file in question		fs_status is not successfully completed, the open file in question
	must not be accessed until that fs_status is fetched.		must not be accessed until that fs_status is fetched.
	</t>		</t>
	<t>		<t>
	The procedure above will ensure that before using any data from the		The procedure above will ensure that before using any data from the
	file system the client has in hand a newly-fetched current version		file system the client has in hand a newly-fetched current version
	of the file system image. Multiple values for multiple requests in		of the file system image. Multiple values for multiple requests in
	flight can be resolved by assembling them into the required partial		flight can be resolved by assembling them into the required partial
	order (and the elements should form a total order within the		order (and the elements should form a total order within the
	partial order) and		partial order) and
	using the last.		using the last.
	The client may then, when switching among		The client may then, when switching among
	file system instances, decline to use an instance that does not have		file system instances, decline to use an instance that does not have
	an fss_type of STATUS4_VERSIONED or whose fss_version field is earlier tha n the		an fss_type of STATUS4_VERSIONED or whose fss_version field is earlier tha n the
	last one obtained from the predecessor file system instance.		last one obtained from the predecessor file system instance.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp $		<section anchor="pnfs" numbered="true" toc="default">
	-->		<name>Parallel NFS (pNFS)</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section anchor="pnfs_intro" numbered="true" toc="default">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>Introduction</name>
	<section title="Parallel NFS (pNFS)" anchor="pnfs">		<t>
	<section title="Introduction" anchor="pnfs_intro">		pNFS is an <bcp14>OPTIONAL</bcp14> feature within NFSv4.1; the pNFS feature
	<t>
	pNFS is an OPTIONAL feature within NFSv4.1; the pNFS feature
	set allows direct client access to the storage devices containing		set allows direct client access to the storage devices containing
	file data. When file data for a single NFSv4 server is stored on		file data. When file data for a single NFSv4 server is stored on
	multiple and/or higher-throughput storage devices (by comparison to		multiple and/or higher-throughput storage devices (by comparison to
	the server's throughput capability), the result can be significantly		the server's throughput capability), the result can be significantly
	better file access performance. The relationship among multiple		better file access performance. The relationship among multiple
	clients, a single server, and multiple storage devices for pNFS		clients, a single server, and multiple storage devices for pNFS
	(server and clients have access to all storage devices) is shown in		(server and clients have access to all storage devices) is shown in
	<xref target="fig_system"/>.		<xref target="fig_system" format="default"/>.
	</t>		</t>
	<figure anchor="fig_system">		<figure anchor="fig_system">
	<artwork><![CDATA[		<artwork name="" type="" align="left" alt=""><![CDATA[
	+-----------+		+-----------+
	|+-----------+ +-----------+		|+-----------+ +-----------+
	||+-----------+ | |		||+-----------+ | |
	||| | NFSv4.1 + pNFS | |		||| | NFSv4.1 + pNFS | |
	+|| Clients |<------------------------------>| Server |		+|| Clients |<------------------------------>| Server |
	+| | | |		+| | | |
	+-----------+ | |		+-----------+ | |
	||| +-----------+		||| +-----------+
	||| |		||| |
	||| |		||| |
	||| Storage +-----------+ |		||| Storage +-----------+ |
	||| Protocol |+-----------+ |		||| Protocol |+-----------+ |
	||+----------------||+-----------+ Control |		||+----------------||+-----------+ Control |
	|+-----------------||| | Protocol|		|+-----------------||| | Protocol|
	+------------------+|| Storage |------------+		+------------------+|| Storage |------------+
	+| Devices |		+| Devices |
	+-----------+		+-----------+
	]]></artwork>		]]></artwork>
	</figure>		</figure>
	<t>		<t>
	In this model, the clients, server, and storage devices are		In this model, the clients, server, and storage devices are
	responsible for managing file access. This is in contrast to NFSv4		responsible for managing file access. This is in contrast to NFSv4
	without pNFS, where it is primarily the server's responsibility; some		without pNFS, where it is primarily the server's responsibility; some
	of this responsibility may be delegated to the client under strictly		of this responsibility may be delegated to the client under strictly
	specified conditions. See <xref target="storage_protocol"/>		specified conditions. See <xref target="storage_protocol" format="default"/>
	for a discussion of the Storage Protocol. See <xref target="control_protocol"/		for a discussion of the Storage Protocol. See <xref target="control_protocol"
	> for a		format="default"/> for a
	discussion of the Control Protocol.		discussion of the Control Protocol.
	</t>		</t>
	<t>		<t>
	pNFS takes the form of OPTIONAL operations that manage protocol		pNFS takes the form of <bcp14>OPTIONAL</bcp14> operations that manage protocol
	objects called 'layouts' (<xref target="layout_types"/>) that		objects called 'layouts' (<xref target="layout_types" format="default"/>) that
	contain a byte-range and storage location information. The layout		contain a byte-range and storage location information. The layout
	is managed in a similar fashion		is managed in a similar fashion
	as NFSv4.1 data delegations. For example, the layout is leased,		as NFSv4.1 data delegations. For example, the layout is leased,
	recallable, and revocable. However, layouts are distinct abstractions		recallable, and revocable. However, layouts are distinct abstractions
	and are manipulated with new operations. When a client holds a		and are manipulated with new operations. When a client holds a
	layout, it is granted the ability to directly access the byte-range		layout, it is granted the ability to directly access the byte-range
	at the storage location specified in the layout.		at the storage location specified in the layout.
	</t>		</t>
	<t>		<t>
	There are interactions between layouts and other NFSv4.1		There are interactions between layouts and other NFSv4.1
	abstractions such as data delegations and byte-range locking.		abstractions such as data delegations and byte-range locking.
	Delegation issues are discussed in <xref		Delegation issues are discussed in <xref target="recalling_layout" format="def
	target="recalling_layout"/>. Byte-range locking issues are		ault"/>. Byte-range locking issues are
	discussed in Sections <xref target="layout_iomode" format="counter" /> and <xr		discussed in Sections <xref target="layout_iomode" format="counter"/> and <xre
	ef		f target="layout_semantics" format="counter"/>.
	target="layout_semantics" format="counter" />.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="pNFS Definitions">		<name>pNFS Definitions</name>
	<t>		<t>
	NFSv4.1's pNFS feature provides parallel data access to a		NFSv4.1's pNFS feature provides parallel data access to a
	file system that stripes its content across multiple		file system that stripes its content across multiple
	storage servers. The first instantiation of pNFS, as		storage servers. The first instantiation of pNFS, as
	part of NFSv4.1, separates the file system protocol		part of NFSv4.1, separates the file system protocol
	processing into two parts: metadata processing and data		processing into two parts: metadata processing and data
	processing. Data consist of the contents of regular		processing. Data consist of the contents of regular
	files that are striped across storage servers. Data		files that are striped across storage servers. Data
	striping occurs in at least two ways: on a file-by-file		striping occurs in at least two ways: on a file-by-file
	basis and, within sufficiently large files, on a		basis and, within sufficiently large files, on a
	block-by-block basis. In contrast, striped access to		block-by-block basis. In contrast, striped access to
	metadata by pNFS clients is not provided in NFSv4.1, even		metadata by pNFS clients is not provided in NFSv4.1, even
	though the file system back end of a pNFS server might		though the file system back end of a pNFS server might
	stripe metadata. Metadata consist of everything else,		stripe metadata. Metadata consist of everything else,
	including the contents of non-regular files (e.g.,		including the contents of non-regular files (e.g.,
	directories); see <xref target="metadata"/>. The		directories); see <xref target="metadata" format="default"/>. The
	metadata functionality is implemented by an NFSv4.1		metadata functionality is implemented by an NFSv4.1
	server that supports pNFS and the operations described in		server that supports pNFS and the operations described in
	<xref target="nfsv41operations" />; such a server is		<xref target="nfsv41operations" format="default"/>; such a server is
	called a metadata server (<xref target="mds"/>).		called a metadata server (<xref target="mds" format="default"/>).
	</t>		</t>
	<t>		<t>
	The data functionality is implemented by one or more storage devices, each of which		The data functionality is implemented by one or more storage devices, each of which
	are accessed by the client via a storage protocol. A subset (defined in <xref		are accessed by the client via a storage protocol. A subset (defined in <xref
	target="ds_ops"		target="ds_ops" format="default"/>) of NFSv4.1 is one such storage protocol. N
	/>) of NFSv4.1 is one such storage protocol. New terms are		ew terms are
	introduced to the NFSv4.1 nomenclature and existing terms are		introduced to the NFSv4.1 nomenclature and existing terms are
	clarified to allow for the description of the pNFS feature.		clarified to allow for the description of the pNFS feature.
	</t>		</t>
			<section anchor="metadata" numbered="true" toc="default">
	<section title="Metadata" anchor="metadata">		<name>Metadata</name>
	<t>		<t>
	Information about a file system object, such as its name, location		Information about a file system object, such as its name, location
	within the namespace, owner, ACL, and other attributes. Metadata may		within the namespace, owner, ACL, and other attributes. Metadata may
	also include storage location information, and this will vary based		also include storage location information, and this will vary based
	on the underlying storage mechanism that is used.		on the underlying storage mechanism that is used.
	</t>		</t>
	</section>		</section>
			<section anchor="mds" numbered="true" toc="default">
	<section title="Metadata Server" anchor="mds">		<name>Metadata Server</name>
	<t>		<t>
	An NFSv4.1 server that supports the pNFS feature. A variety of		An NFSv4.1 server that supports the pNFS feature. A variety of
	architectural choices exist for the metadata server and its use of		architectural choices exist for the metadata server and its use of
	file system information held at the server. Some servers may		file system information held at the server. Some servers may
	contain metadata only for file objects residing at the		contain metadata only for file objects residing at the
	metadata server, while the file data resides on associated storage		metadata server, while the file data resides on associated storage
	devices. Other metadata servers may hold both metadata and a		devices. Other metadata servers may hold both metadata and a
	varying degree of file data.		varying degree of file data.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="pNFS Client">		<name>pNFS Client</name>
	<t>		<t>
	An NFSv4.1 client that supports pNFS operations and supports at		An NFSv4.1 client that supports pNFS operations and supports at
	least one storage protocol for performing I/O		least one storage protocol for performing I/O
	to storage devices.		to storage devices.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="Storage Device">		<name>Storage Device</name>
	<t>		<t>
	A storage device stores a regular file's data, but leaves metadata		A storage device stores a regular file's data, but leaves metadata
	management to the metadata server. A storage device could be		management to the metadata server. A storage device could be
	another NFSv4.1 server, an object-based storage device (OSD),		another NFSv4.1 server, an object-based storage device (OSD),
	a block		a block
	device accessed over a System Area Network (SAN, e.g., either		device accessed over a System Area Network (SAN, e.g., either
	FiberChannel or iSCSI SAN), or some other entity.		FiberChannel or iSCSI SAN), or some other entity.
	</t>		</t>
	</section>		</section>
			<section anchor="storage_protocol" numbered="true" toc="default">
	<section anchor="storage_protocol" title="Storage Protocol">		<name>Storage Protocol</name>
	<t>		<t>
	As noted in <xref		As noted in <xref target="fig_system" format="default"/>,
	target="fig_system"/>,
	the storage protocol is the method used by the client to		the storage protocol is the method used by the client to
	store and retrieve data directly from the storage devices.		store and retrieve data directly from the storage devices.
	</t>		</t>
	<t>		<t>
	The NFSv4.1 pNFS feature has been structured to allow for a variety		The NFSv4.1 pNFS feature has been structured to allow for a variety
	of storage protocols to be defined and used.		of storage protocols to be defined and used.
	One example storage protocol is NFSv4.1 itself (as documented in <xref		One example storage protocol is NFSv4.1 itself (as documented in
	target="file_layout_type"/>). Other options for the storage protocol		<xref target="file_layout_type" format="default"/>). Other options for the st
			orage protocol
	are described elsewhere and include:		are described elsewhere and include:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	Block/volume protocols such as Internet SCSI (iSCSI) <xref target="RFC3720		<li>
	"		Block/volume protocols such as Internet SCSI (iSCSI)
	/> and FCP <xref target="FCP-2" />. The block/volume		<xref target="RFC7143" format="default"/> and FCP <xref target="FCP-2" for
			mat="default"/>. The block/volume
	protocol support can be independent of the addressing structure		protocol support can be independent of the addressing structure
	of the block/volume protocol used, allowing more than one		of the block/volume protocol used, allowing more than one
	protocol to access the same file data and enabling extensibility		protocol to access the same file data and enabling extensibility
	to other block/volume protocols. See		to other block/volume protocols. See
	<xref target="RFC5663"/> for a layout		<xref target="RFC5663" format="default"/> for a layout
	specification that		specification that
	allows pNFS to use block/volume storage protocols.		allows pNFS to use block/volume storage protocols.
	</t>		</li>
	<t>		<li>
	Object protocols such as OSD over iSCSI or Fibre Channel <xref		Object protocols such as OSD over iSCSI or Fibre Channel <xref target="OSD
	target="OSD-T10" />. See		-T10" format="default"/>. See
	<xref target="RFC5664"/> for a layout specification		<xref target="RFC5664" format="default"/> for a layout specification
	that allows pNFS to use object storage protocols.		that allows pNFS to use object storage protocols.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	It is possible that various storage protocols are available to		It is possible that various storage protocols are available to
	both client and server and it may be possible that a client and		both client and server and it may be possible that a client and
	server do not have a matching storage protocol available to them.		server do not have a matching storage protocol available to them.
	Because of this, the pNFS server MUST support normal NFSv4.1 access		Because of this, the pNFS server <bcp14>MUST</bcp14> support normal NFSv4.1 ac cess
	to any file accessible by the pNFS feature; this will allow for		to any file accessible by the pNFS feature; this will allow for
	continued interoperability between an NFSv4.1 client and server.		continued interoperability between an NFSv4.1 client and server.
	</t>		</t>
	</section>		</section>
			<section anchor="control_protocol" numbered="true" toc="default">
	<section anchor="control_protocol" title="Control Protocol">		<name>Control Protocol</name>
	<t>		<t>
	As noted in <xref		As noted in <xref target="fig_system" format="default"/>,
	target="fig_system"/>,
	the control protocol is used by the exported file system between the		the control protocol is used by the exported file system between the
	metadata server and storage devices. Specification of such		metadata server and storage devices. Specification of such
	protocols is outside the scope of the NFSv4.1 protocol. Such		protocols is outside the scope of the NFSv4.1 protocol. Such
	control protocols would be used to control activities such as the		control protocols would be used to control activities such as the
	allocation and deallocation of storage, the management of state		allocation and deallocation of storage, the management of state
	required by the storage devices to perform client access control,		required by the storage devices to perform client access control,
	and, depending on the storage protocol, the enforcement of		and, depending on the storage protocol, the enforcement of
	authentication and authorization so that restrictions that		authentication and authorization so that restrictions that
	would be enforced by the metadata server are also enforced by		would be enforced by the metadata server are also enforced by
	the storage device.		the storage device.
	</t>		</t>
	<t>		<t>
	A particular control protocol is not REQUIRED by NFSv4.1 but		A particular control protocol is not <bcp14>REQUIRED</bcp14> by NFSv4.1 but
	requirements are placed on the control protocol for maintaining		requirements are placed on the control protocol for maintaining
	attributes like modify time, the change attribute, and the end-of-file		attributes like modify time, the change attribute, and the end-of-file
	(EOF) position. Note that if pNFS is layered over a clustered, parallel		(EOF) position. Note that if pNFS is layered over a clustered, parallel
	file system (e.g., <xref target="PVFS">PVFS</xref>), the mechanisms that		file system (e.g., <xref target="PVFS" format="default">PVFS</xref>), the mech anisms that
	enable clustering and parallelism in that file system can be considered		enable clustering and parallelism in that file system can be considered
	the control protocol.		the control protocol.
	</t>		</t>
	</section>		</section>
			<section anchor="layout_types" numbered="true" toc="default">
	<section anchor="layout_types" title="Layout Types">		<name>Layout Types</name>
	<t>		<t>
	A layout describes the mapping of a file's data to the storage		A layout describes the mapping of a file's data to the storage
	devices that hold the data. A layout is said to belong to a		devices that hold the data. A layout is said to belong to a
	specific layout type (data type layouttype4, see <xref		specific layout type (data type layouttype4, see <xref target="layouttype4" fo
	target="layouttype4" />). The layout type allows for variants to		rmat="default"/>). The layout type allows for variants to
	handle different storage protocols, such as those associated with		handle different storage protocols, such as those associated with
	block/volume <xref target="RFC5663" />, object <xref		block/volume <xref target="RFC5663" format="default"/>, object <xref target="R
	target="RFC5664" />, and file (<xref target="file_layout_type"		FC5664" format="default"/>, and file (<xref target="file_layout_type" format="de
	/>) layout types. A metadata server, along with its control		fault"/>) layout types. A metadata server, along with its control
	protocol, MUST support at least one layout type. A private		protocol, <bcp14>MUST</bcp14> support at least one layout type. A private
	sub-range of the layout type namespace is also defined. Values from		sub-range of the layout type namespace is also defined. Values from
	the private layout type range MAY be used for internal testing or		the private layout type range <bcp14>MAY</bcp14> be used for internal testing
	experimentation (see <xref target="layouttype4"/>).		or
			experimentation (see <xref target="layouttype4" format="default"/>).
	</t>		</t>
	<t>		<t>
	As an example, the organization of the file layout type could be		As an example, the organization of the file layout type could be
	an array of tuples (e.g., device ID, filehandle), along with a		an array of tuples (e.g., device ID, filehandle), along with a
	definition of how the data is		definition of how the data is
	stored across the devices (e.g., striping). A block/volume layout		stored across the devices (e.g., striping). A block/volume layout
	might be an array of tuples that store &lt;device ID, block number,		might be an array of tuples that store &lt;device ID, block number,
	block count&gt;		block count&gt;
	along with information about block size and the		along with information about block size and the
	associated file offset of the block number. An object layout might		associated file offset of the block number. An object layout might
	be an array of tuples &lt;device ID, object ID&gt; and an additional		be an array of tuples &lt;device ID, object ID&gt; and an additional
	structure (i.e., the aggregation map) that defines how the logical		structure (i.e., the aggregation map) that defines how the logical
	byte sequence of the file data is serialized into the different		byte sequence of the file data is serialized into the different
	objects. Note that the actual layouts are typically more complex		objects. Note that the actual layouts are typically more complex
	than these simple expository examples.		than these simple expository examples.
	</t>		</t>
	<t>		<t>
	Requests for pNFS-related operations will often specify a layout		Requests for pNFS-related operations will often specify a layout
	type. Examples of such operations are GETDEVICEINFO and LAYOUTGET.		type. Examples of such operations are GETDEVICEINFO and LAYOUTGET.
	The response for these operations will include structures such		The response for these operations will include structures such
	as a device_addr4 or a layout4, each of which includes a layout type within		as a device_addr4 or a layout4, each of which includes a layout type within
	it. The layout type sent by the server MUST always be the same		it. The layout type sent by the server <bcp14>MUST</bcp14> always be the same
	one requested by the client. When a server sends a response that		one requested by the client. When a server sends a response that
	includes a different layout type, the client SHOULD ignore the		includes a different layout type, the client <bcp14>SHOULD</bcp14> ignore the
	response and behave as if the server had returned an error response.		response and behave as if the server had returned an error response.
	</t>		</t>
	</section>		</section>
			<section anchor="layout" numbered="true" toc="default">
	<section title="Layout" anchor="layout">		<name>Layout</name>
	<t>		<t>
	A layout defines how a file's data is organized on one or more		A layout defines how a file's data is organized on one or more
	storage devices. There are many potential layout types; each of the		storage devices. There are many potential layout types; each of the
	layout types are differentiated by the storage protocol used to		layout types are differentiated by the storage protocol used to
	access data and by the aggregation scheme that lays out the file		access data and by the aggregation scheme that lays out the file
	data on the underlying storage devices. A layout is precisely		data on the underlying storage devices. A layout is precisely
	identified by the tuple &lt;client ID, filehandle, layout		identified by the tuple &lt;client ID, filehandle, layout
	type, iomode, range&gt;, where filehandle refers to the filehandle		type, iomode, range&gt;, where filehandle refers to the filehandle
	of the file on the metadata server.		of the file on the metadata server.
	</t>		</t>
	<t>		<t>
	It is important to define when layouts overlap and/or conflict with		It is important to define when layouts overlap and/or conflict with
	each other. For two layouts with overlapping byte-ranges to		each other. For two layouts with overlapping byte-ranges to
	actually overlap each other, both layouts must be of the same layout		actually overlap each other, both layouts must be of the same layout
	type, correspond to the same filehandle, and have the same iomode.		type, correspond to the same filehandle, and have the same iomode.
	Layouts conflict when they overlap and differ in the content of the		Layouts conflict when they overlap and differ in the content of the
	layout (i.e., the storage device/file mapping parameters differ).		layout (i.e., the storage device/file mapping parameters differ).
	Note that differing iomodes do not lead to conflicting layouts. It		Note that differing iomodes do not lead to conflicting layouts. It
	is permissible for layouts with different iomodes, pertaining to the		is permissible for layouts with different iomodes, pertaining to the
	same byte-range, to be held by the same client. An example of this		same byte-range, to be held by the same client. An example of this
	would be copy-on-write functionality for a block/volume layout type.		would be copy-on-write functionality for a block/volume layout type.
	</t>		</t>
			</section>
	</section>		<section anchor="layout_iomode" numbered="true" toc="default">
	<section title="Layout Iomode" anchor="layout_iomode">		<name>Layout Iomode</name>
	<t>		<t>
	The layout iomode (data type layoutiomode4, see <xref		The layout iomode (data type layoutiomode4, see <xref target="layoutiomode4" f
	target="layoutiomode4" />) indicates to the metadata server the		ormat="default"/>) indicates to the metadata server the
	client's intent to perform either just READ operations		client's intent to perform either just READ operations
	or a mixture containing READ		or a mixture containing READ
	and WRITE operations. For certain layout		and WRITE operations. For certain layout
	types, it is useful for a client to specify this intent at the time it sends L AYOUTGET		types, it is useful for a client to specify this intent at the time it sends L AYOUTGET
	(<xref target="OP_LAYOUTGET" />). For example, for		(<xref target="OP_LAYOUTGET" format="default"/>). For example, for
	block/volume-based protocols, block allocation could occur when a		block/volume-based protocols, block allocation could occur when a
	LAYOUTIOMODE4_RW iomode is specified. A special LAYOUTIOMODE4_ANY iomode is d efined		LAYOUTIOMODE4_RW iomode is specified. A special LAYOUTIOMODE4_ANY iomode is d efined
	and can only be used for LAYOUTRETURN and CB_LAYOUTRECALL, not for		and can only be used for LAYOUTRETURN and CB_LAYOUTRECALL, not for
	LAYOUTGET. It specifies that layouts pertaining to both LAYOUTIOMODE4_READ an d		LAYOUTGET. It specifies that layouts pertaining to both LAYOUTIOMODE4_READ an d
	LAYOUTIOMODE4_RW iomodes are being returned or recalled, respectively.		LAYOUTIOMODE4_RW iomodes are being returned or recalled, respectively.
	</t>		</t>
	<t>		<t>
	A storage device may validate I/O with regard to the iomode; this		A storage device may validate I/O with regard to the iomode; this
	is dependent upon storage device implementation and layout type.		is dependent upon storage device implementation and layout type.
	Thus, if the client's layout iomode is inconsistent with the I/O		Thus, if the client's layout iomode is inconsistent with the I/O
	being performed, the storage device may reject the client's I/O with		being performed, the storage device may reject the client's I/O with
	an error indicating that a new layout with the correct iomode should be		an error indicating that a new layout with the correct iomode should be
	obtained via LAYOUTGET. For example, if a client gets a layout with a LAYOUTI OMODE4_READ iomode and		obtained via LAYOUTGET. For example, if a client gets a layout with a LAYOUTI OMODE4_READ iomode and
	performs a WRITE to a storage device, the storage device is allowed		performs a WRITE to a storage device, the storage device is allowed
	to reject that WRITE.		to reject that WRITE.
	</t>		</t>
	<t>		<t>
	The use of the layout iomode does not conflict with OPEN share modes or byte-r ange LOCK operations;		The use of the layout iomode does not conflict with OPEN share modes or byte-r ange LOCK operations;
	open share mode and byte-range lock conflicts are enforced as they are without the		open share mode and byte-range lock conflicts are enforced as they are without the
	use of pNFS and are logically separate from the pNFS layout level.		use of pNFS and are logically separate from the pNFS layout level.
	Open share modes and byte-range locks are the preferred method for		Open share modes and byte-range locks are the preferred method for
	restricting user access to data files. For example, an OPEN of		restricting user access to data files. For example, an OPEN of
	OPEN4_SHARE_ACCESS_WRITE does not conflict with a LAYOUTGET containing an iomo de		OPEN4_SHARE_ACCESS_WRITE does not conflict with a LAYOUTGET containing an iomo de
	of LAYOUTIOMODE4_RW performed by another client. Applications that depend		of LAYOUTIOMODE4_RW performed by another client. Applications that depend
	on writing into the same file concurrently may use byte-range locking to		on writing into the same file concurrently may use byte-range locking to
	serialize their accesses.		serialize their accesses.
	</t>		</t>
	</section>		</section>
			<section anchor="device_ids" numbered="true" toc="default">
	<section title="Device IDs" anchor="device_ids">		<name>Device IDs</name>
	<t>		<t>
	The device ID (data type deviceid4, see		The device ID (data type deviceid4, see
	<xref target="deviceid4"/>) identifies a group of storage devices. The scope		<xref target="deviceid4" format="default"/>) identifies a group of storage d evices. The scope
	of a device ID is the pair &lt;client ID, layout type&gt;. In practice, a		of a device ID is the pair &lt;client ID, layout type&gt;. In practice, a
	significant amount of information may be required to fully address		significant amount of information may be required to fully address
	a storage device. Rather than embedding all such information in a		a storage device. Rather than embedding all such information in a
	layout, layouts embed device IDs. The NFSv4.1 operation		layout, layouts embed device IDs. The NFSv4.1 operation
	GETDEVICEINFO (<xref target="OP_GETDEVICEINFO" />) is used to		GETDEVICEINFO (<xref target="OP_GETDEVICEINFO" format="default"/>) is used t o
	retrieve the complete address information (including		retrieve the complete address information (including
	all device addresses for the device ID) regarding the storage		all device addresses for the device ID) regarding the storage
	device according to its layout type and device ID. For example,		device according to its layout type and device ID. For example,
	the address of an NFSv4.1 data server or of an object-based storage		the address of an NFSv4.1 data server or of an object-based storage
	device could be an IP address and port. The address of a block		device could be an IP address and port. The address of a block
	storage device could be a volume label.		storage device could be a volume label.
	</t>		</t>
	<t>		<t>
	Clients cannot expect the mapping between a device ID and		Clients cannot expect the mapping between a device ID and
	its storage device address(es) to persist across metadata server restart.		its storage device address(es) to persist across metadata server restart.
	See <xref target="mds_recovery" /> for a description of how		See <xref target="mds_recovery" format="default"/> for a description of how
	recovery works in that situation.		recovery works in that situation.
	</t>		</t>
	<t>		<t>
	A device ID lives as long as there is a layout		A device ID lives as long as there is a layout
	referring to the device ID. If there are no layouts		referring to the device ID. If there are no layouts
	referring to the device ID, the server is free to		referring to the device ID, the server is free to
	delete the device ID any time.		delete the device ID any time.
	Once a device ID is deleted by the server, the server MUST NOT		Once a device ID is deleted by the server, the server <bcp14>MUST NOT</bcp14 >
	reuse the device ID for the same layout type and client ID again.		reuse the device ID for the same layout type and client ID again.
	This requirement is feasible because the device ID is 16 bytes		This requirement is feasible because the device ID is 16 bytes
	long, leaving sufficient room to store a generation number if the		long, leaving sufficient room to store a generation number if the
	server's implementation requires most of the rest of the device ID's		server's implementation requires most of the rest of the device ID's
	content to be reused. This requirement is necessary because		content to be reused. This requirement is necessary because
	otherwise the race conditions between asynchronous notification		otherwise the race conditions between asynchronous notification
	of device ID addition and deletion would be too difficult to		of device ID addition and deletion would be too difficult to
	sort out.		sort out.
	</t>		</t>
	<t>		<t>
	Device ID to device address mappings are not leased,		Device ID to device address mappings are not leased,
	and can be changed at any time. (Note that while		and can be changed at any time. (Note that while
	device ID to device address mappings are likely		device ID to device address mappings are likely
	to change after the metadata server restarts, the		to change after the metadata server restarts, the
	server is not required to change the mappings.)		server is not required to change the mappings.)
	A server has two		A server has two
	choices for changing mappings. It can recall all		choices for changing mappings. It can recall all
	layouts referring to the device ID or it can use a		layouts referring to the device ID or it can use a
	notification mechanism.		notification mechanism.
	</t>		</t>
	<t>		<t>
	The NFSv4.1 protocol has no optimal way to recall		The NFSv4.1 protocol has no optimal way to recall
	all layouts that referred to a particular device ID		all layouts that referred to a particular device ID
	(unless the server associates a single device ID with		(unless the server associates a single device ID with
	a single fsid or a single client ID; in which case,		a single fsid or a single client ID; in which case,
	CB_LAYOUTRECALL has options for recalling all layouts		CB_LAYOUTRECALL has options for recalling all layouts
	associated with the fsid, client ID pair, or just the		associated with the fsid, client ID pair, or just the
	client ID).		client ID).
	</t>		</t>
	<t>		<t>
	Via a notification mechanism		Via a notification mechanism
	(see <xref target="OP_CB_NOTIFY_DEVICEID" />),		(see <xref target="OP_CB_NOTIFY_DEVICEID" format="default"/>),
	device ID to device address mappings can change over the duration		device ID to device address mappings can change over the duration
	of server operation without recalling or revoking the layouts that		of server operation without recalling or revoking the layouts that
	refer to device ID. The notification mechanism can also delete		refer to device ID. The notification mechanism can also delete
	a device ID, but only if the client has no layouts referring		a device ID, but only if the client has no layouts referring
	to the device ID.		to the device ID.
	A notification of a change to a device ID to device address		A notification of a change to a device ID to device address
	mapping will immediately or eventually invalidate some or all of		mapping will immediately or eventually invalidate some or all of
	the device ID's mappings.		the device ID's mappings.
	The server MUST support notifications and the client must		The server <bcp14>MUST</bcp14> support notifications and the client must
	request them before they can be used. For further information		request them before they can be used. For further information
	about the notification types <xref target="OP_CB_NOTIFY_DEVICEID" />.		about the notification types, see <xref target="OP_CB_NOTIFY_DEVICEID" forma
			t="default"/>.
	</t>
	</section>
	</section>
	<section title="pNFS Operations" anchor="pnfs_ops">		</t>
	<t>		</section>
			</section>
			<section anchor="pnfs_ops" numbered="true" toc="default">
			<name>pNFS Operations</name>
			<t>
	NFSv4.1 has several operations that are needed for		NFSv4.1 has several operations that are needed for
	pNFS servers, regardless of layout type or storage		pNFS servers, regardless of layout type or storage
	protocol. These operations are all sent to a metadata		protocol. These operations are all sent to a metadata
	server and summarized here. While pNFS is an OPTIONAL		server and summarized here. While pNFS is an <bcp14>OPTIONAL</bcp14>
	feature, if pNFS is implemented, some operations		feature, if pNFS is implemented, some operations
	are REQUIRED in order to comply with pNFS. See <xref		are <bcp14>REQUIRED</bcp14> in order to comply with pNFS. See <xref target="op
	target="operation_mandlist"/>.		eration_mandlist" format="default"/>.
	</t>		</t>
	<t>		<t>
	These are the fore channel pNFS operations:		These are the fore channel pNFS operations:
	<list style='hanging'>		</t>
	<t hangText="GETDEVICEINFO">		<dl newline="false" spacing="normal">
	(<xref target="OP_GETDEVICEINFO" />), as noted previously		<dt>GETDEVICEINFO</dt>
	(<xref target="device_ids" />), returns the mapping of device ID to		<dd>
			(<xref target="OP_GETDEVICEINFO" format="default"/>), as noted previously
			(<xref target="device_ids" format="default"/>), returns the mapping of device
			ID to
	storage device address.		storage device address.
	</t>		</dd>
			<dt>GETDEVICELIST</dt>
	<t hangText="GETDEVICELIST">		<dd>
	(<xref target="OP_GETDEVICELIST" />)		(<xref target="OP_GETDEVICELIST" format="default"/>)
	allows clients to fetch all device IDs		allows clients to fetch all device IDs
	for a specific file system.		for a specific file system.
	</t>		</dd>
	<t hangText="LAYOUTGET">		<dt>LAYOUTGET</dt>
	(<xref target="OP_LAYOUTGET" />) is used by a client to get		<dd>
			(<xref target="OP_LAYOUTGET" format="default"/>) is used by a client to get
	a layout for a file.		a layout for a file.
	</t>		</dd>
	<t hangText="LAYOUTCOMMIT">		<dt>LAYOUTCOMMIT</dt>
	(<xref target="OP_LAYOUTCOMMIT" />) is used		<dd>
			(<xref target="OP_LAYOUTCOMMIT" format="default"/>) is used
	to inform the metadata server of the client's intent to commit data		to inform the metadata server of the client's intent to commit data
	that has been written to the storage device (the storage device as		that has been written to the storage device (the storage device as
	originally indicated in the return value of LAYOUTGET).		originally indicated in the return value of LAYOUTGET).
	</t>		</dd>
	<t hangText="LAYOUTRETURN">		<dt>LAYOUTRETURN</dt>
	(<xref target="OP_LAYOUTRETURN" />) is used		<dd>
			(<xref target="OP_LAYOUTRETURN" format="default"/>) is used
	to return layouts for a file, a file system ID (FSID), or a client ID.		to return layouts for a file, a file system ID (FSID), or a client ID.
	</t>		</dd>
	</list>		</dl>
	</t>		<t>
	<t>
	These are the backchannel pNFS operations:		These are the backchannel pNFS operations:
	<list style='hanging'>		</t>
	<t hangText="CB_LAYOUTRECALL">		<dl newline="false" spacing="normal">
	(<xref target="OP_CB_LAYOUTRECALL" />) recalls		<dt>CB_LAYOUTRECALL</dt>
			<dd>
			(<xref target="OP_CB_LAYOUTRECALL" format="default"/>) recalls
	a layout, all layouts belonging to a file system, or all		a layout, all layouts belonging to a file system, or all
	layouts belonging to a client ID.		layouts belonging to a client ID.
	</t>		</dd>
	<t hangText="CB_RECALL_ANY">		<dt>CB_RECALL_ANY</dt>
	(<xref target="OP_CB_RECALL_ANY" />)		<dd>
			(<xref target="OP_CB_RECALL_ANY" format="default"/>)
	tells a client that it needs to return some number of recallable		tells a client that it needs to return some number of recallable
	objects, including layouts, to the metadata server.		objects, including layouts, to the metadata server.
	</t>		</dd>
	<t hangText="CB_RECALLABLE_OBJ_AVAIL">		<dt>CB_RECALLABLE_OBJ_AVAIL</dt>
	(<xref target="OP_CB_RECALLABLE_OBJ_AVAIL" />) tells a client		<dd>
			(<xref target="OP_CB_RECALLABLE_OBJ_AVAIL" format="default"/>) tells a client
	that a recallable object that it was denied (in case of		that a recallable object that it was denied (in case of
	pNFS, a layout denied by LAYOUTGET) due to resource exhaustion		pNFS, a layout denied by LAYOUTGET) due to resource exhaustion
	is now available.		is now available.
	</t>		</dd>
	<t hangText="CB_NOTIFY_DEVICEID">		<dt>CB_NOTIFY_DEVICEID</dt>
	(<xref target="OP_CB_NOTIFY_DEVICEID" />) notifies the client of		<dd>
			(<xref target="OP_CB_NOTIFY_DEVICEID" format="default"/>) notifies the client
			of
	changes to device IDs.		changes to device IDs.
	</t>		</dd>
	</list>		</dl>
	</t>		</section>
			<section anchor="pnfs_attr" numbered="true" toc="default">
	</section>		<name>pNFS Attributes</name>
	<section title="pNFS Attributes" anchor="pnfs_attr">		<t>
	<t>
	A number of attributes specific to pNFS are listed and described in		A number of attributes specific to pNFS are listed and described in
	<xref target="pnfs_attr_full" />.		<xref target="pnfs_attr_full" format="default"/>.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="Layout Semantics">		<name>Layout Semantics</name>
			<section anchor="layout_semantics" numbered="true" toc="default">
	<section title="Guarantees Provided by Layouts" anchor="layout_semantics">		<name>Guarantees Provided by Layouts</name>
	<t>		<t>
	Layouts grant to the client the ability to access data located at		Layouts grant to the client the ability to access data located at
	a storage device with the appropriate storage protocol. The client		a storage device with the appropriate storage protocol. The client
	is guaranteed the layout will be recalled when one of two things		is guaranteed the layout will be recalled when one of two things
	occur: either a conflicting layout is requested or the state		occur: either a conflicting layout is requested or the state
	encapsulated by the layout becomes invalid (this can happen when		encapsulated by the layout becomes invalid (this can happen when
	an event directly or indirectly modifies the layout). When a layout		an event directly or indirectly modifies the layout). When a layout
	is recalled and returned by the client, the client continues with		is recalled and returned by the client, the client continues with
	the ability to access file data with normal NFSv4.1 operations		the ability to access file data with normal NFSv4.1 operations
	through the metadata server. Only the ability to access the storage		through the metadata server. Only the ability to access the storage
	devices is affected.		devices is affected.
	</t>		</t>
	<t>		<t>
	The requirement of NFSv4.1 that all user access rights MUST be		The requirement of NFSv4.1 that all user access rights <bcp14>MUST</bcp14> be
	obtained through the appropriate OPEN, LOCK, and ACCESS operations		obtained through the appropriate OPEN, LOCK, and ACCESS operations
	is not modified with the existence of layouts. Layouts are provided		is not modified with the existence of layouts. Layouts are provided
	to NFSv4.1 clients, and user access still follows the rules of the		to NFSv4.1 clients, and user access still follows the rules of the
	protocol as if they did not exist. It is a requirement that for a		protocol as if they did not exist. It is a requirement that for a
	client to access a storage device, a layout must be held by the		client to access a storage device, a layout must be held by the
	client. If a storage device receives an I/O request for a byte-range for		client. If a storage device receives an I/O request for a byte-range for
	which the client does not hold a layout, the storage device SHOULD		which the client does not hold a layout, the storage device <bcp14>SHOULD</bcp 14>
	reject that I/O request. Note that the act of modifying a file for		reject that I/O request. Note that the act of modifying a file for
	which a layout is held does not necessarily conflict with the		which a layout is held does not necessarily conflict with the
	holding of the layout that describes the file being modified.		holding of the layout that describes the file being modified.
	Therefore, it is the requirement of the storage protocol or layout		Therefore, it is the requirement of the storage protocol or layout
	type that determines the necessary behavior. For example,		type that determines the necessary behavior. For example,
	block/volume layout types require that the layout's		block/volume layout types require that the layout's
	iomode agree with the type of I/O being performed.		iomode agree with the type of I/O being performed.
	</t>		</t>
	<t>		<t>
	Depending upon the layout type and storage protocol in use, storage		Depending upon the layout type and storage protocol in use, storage
	device access permissions may be granted by LAYOUTGET and may be		device access permissions may be granted by LAYOUTGET and may be
	encoded within the type-specific layout. For an example of storage		encoded within the type-specific layout. For an example of storage
	device access permissions, see an object-based protocol such as <xref		device access permissions, see an object-based protocol such as <xref target="
	target="OSD-T10" />. If access permissions are encoded within the		OSD-T10" format="default"/>. If access permissions are encoded within the
	layout, the metadata server SHOULD recall the layout when those		layout, the metadata server <bcp14>SHOULD</bcp14> recall the layout when those
	permissions become invalid for any reason -- for example, when a file		permissions become invalid for any reason -- for example, when a file
	becomes unwritable or inaccessible to a client. Note, clients are		becomes unwritable or inaccessible to a client. Note, clients are
	still required to perform the appropriate		still required to perform the appropriate
	OPEN, LOCK, and ACCESS operations as described above. The degree to which it is		OPEN, LOCK, and ACCESS operations as described above. The degree to which it is
	possible for the client to circumvent these operations and		possible for the client to circumvent these operations and
	the consequences of doing so must be clearly specified by the		the consequences of doing so must be clearly specified by the
	individual layout type specifications. In addition, these		individual layout type specifications. In addition, these
	specifications must be clear about the requirements and		specifications must be clear about the requirements and
	non-requirements for the checking performed by the server.		non-requirements for the checking performed by the server.
	</t>		</t>
	<t>		<t>
	In the presence of pNFS functionality, mandatory byte-range locks MUST		In the presence of pNFS functionality, mandatory byte-range locks <bcp14>MUST<
			/bcp14>
	behave as they would without pNFS. Therefore, if mandatory file		behave as they would without pNFS. Therefore, if mandatory file
	locks and layouts are provided simultaneously, the storage device		locks and layouts are provided simultaneously, the storage device
	MUST be able to enforce the mandatory byte-range locks. For example, if		<bcp14>MUST</bcp14> be able to enforce the mandatory byte-range locks. For ex ample, if
	one client obtains a mandatory byte-range lock and a second client accesses th e		one client obtains a mandatory byte-range lock and a second client accesses th e
	storage device, the storage device MUST appropriately restrict I/O		storage device, the storage device <bcp14>MUST</bcp14> appropriately restrict I/O
	for the range of the mandatory byte-range lock. If the storage		for the range of the mandatory byte-range lock. If the storage
	device is incapable of providing this check in the presence of		device is incapable of providing this check in the presence of
	mandatory byte-range locks, then the metadata server MUST NOT grant		mandatory byte-range locks, then the metadata server <bcp14>MUST NOT</bcp14> g rant
	layouts and mandatory byte-range locks simultaneously.		layouts and mandatory byte-range locks simultaneously.
	</t>		</t>
	</section>		</section>
			<section anchor="obtaining_layout" numbered="true" toc="default">
	<section title="Getting a Layout" anchor="obtaining_layout">		<name>Getting a Layout</name>
	<t>		<t>
	A client obtains a layout with the		A client obtains a layout with the
	LAYOUTGET operation. The metadata server		LAYOUTGET operation. The metadata server
	will grant layouts of a particular type		will grant layouts of a particular type
	(e.g., block/volume, object, or file).		(e.g., block/volume, object, or file).
	The client selects an appropriate layout		The client selects an appropriate layout
	type that the server supports and the client		type that the server supports and the client
	is prepared to use. The layout returned to		is prepared to use. The layout returned to
	the client might not exactly match the		the client might not exactly match the
	requested byte-range as described in <xref		requested byte-range as described in <xref target="OP_LAYOUTGET_DESCRIPTION" f
	target="OP_LAYOUTGET_DESCRIPTION"/>. As needed a client		ormat="default"/>. As needed a client
	may send multiple LAYOUTGET operations; these might result		may send multiple LAYOUTGET operations; these might result
	in multiple overlapping, non-conflicting layouts (see		in multiple overlapping, non-conflicting layouts (see
	<xref target="layout"/>).		<xref target="layout" format="default"/>).
	</t>		</t>
	<t>		<t>
	In order to get a layout, the client must first have opened the file		In order to get a layout, the client must first have opened the file
	via the OPEN operation. When a client has no layout on a file, it		via the OPEN operation. When a client has no layout on a file, it
	MUST present an open stateid, a delegation stateid, or		<bcp14>MUST</bcp14> present an open stateid, a delegation stateid, or
	a byte-range lock stateid in the loga_stateid argument. A successful		a byte-range lock stateid in the loga_stateid argument. A successful
	LAYOUTGET result includes a layout stateid. The first successful		LAYOUTGET result includes a layout stateid. The first successful
	LAYOUTGET processed by the server using a non-layout stateid as an		LAYOUTGET processed by the server using a non-layout stateid as an
	argument MUST have the "seqid" field of the layout stateid in the		argument <bcp14>MUST</bcp14> have the "seqid" field of the layout stateid in t
	response set to one. Thereafter, the client MUST use a layout		he
	stateid (see <xref target="layout_stateid" />) on future invocations		response set to one. Thereafter, the client <bcp14>MUST</bcp14> use a layout
	of LAYOUTGET on the file, and the "seqid" MUST NOT be set to		stateid (see <xref target="layout_stateid" format="default"/>) on future invoc
			ations
			of LAYOUTGET on the file, and the "seqid" <bcp14>MUST NOT</bcp14> be set to
	zero. Once the layout has been retrieved, it can be held across		zero. Once the layout has been retrieved, it can be held across
	multiple OPEN and CLOSE sequences. Therefore, a client may hold a		multiple OPEN and CLOSE sequences. Therefore, a client may hold a
	layout for a file that is not currently open by any user on the		layout for a file that is not currently open by any user on the
	client. This allows for the caching of layouts beyond CLOSE.		client. This allows for the caching of layouts beyond CLOSE.
	</t>		</t>
	<t>		<t>
	The storage protocol used by the client to access the data on the		The storage protocol used by the client to access the data on the
	storage device is determined by the layout's type. The client is		storage device is determined by the layout's type. The client is
	responsible for matching the layout type with an available method to		responsible for matching the layout type with an available method to
	interpret and use the layout. The method for this layout type		interpret and use the layout. The method for this layout type
	selection is outside the scope of the pNFS functionality.		selection is outside the scope of the pNFS functionality.
	</t>		</t>
	<t>		<t>
	Although the metadata server is in control		Although the metadata server is in control
	of the layout for a file, the pNFS client		of the layout for a file, the pNFS client
	can provide hints to the server when a file		can provide hints to the server when a file
	is opened or created about the preferred		is opened or created about the preferred
	layout type and aggregation schemes.		layout type and aggregation schemes.
	pNFS introduces a layout_hint attribute (<xref		pNFS introduces a layout_hint attribute (<xref target="attrdef_layout_hint" fo
	target="attrdef_layout_hint" />)		rmat="default"/>)
	that the client can set at file creation		that the client can set at file creation
	time to provide a hint to the server for new		time to provide a hint to the server for new
	files. Setting this attribute separately,		files. Setting this attribute separately,
	after the file has been created might make		after the file has been created might make
	it difficult, or impossible, for the server		it difficult, or impossible, for the server
	implementation to comply.		implementation to comply.
	</t>		</t>
	<t>		<t>
	Because the EXCLUSIVE4 createmode4 does not allow the		Because the EXCLUSIVE4 createmode4 does not allow the
	setting of attributes at file creation time, NFSv4.1		setting of attributes at file creation time, NFSv4.1
	introduces the EXCLUSIVE4_1 createmode4, which does		introduces the EXCLUSIVE4_1 createmode4, which does
	allow attributes to be set at file creation time. In		allow attributes to be set at file creation time. In
	addition, if the session is created with persistent		addition, if the session is created with persistent
	reply caches, EXCLUSIVE4_1 is neither necessary		reply caches, EXCLUSIVE4_1 is neither necessary
	nor allowed. Instead, GUARDED4 both works better and is		nor allowed. Instead, GUARDED4 both works better and is
	prescribed. <xref target="exclusive_create" /> in <xref		prescribed. <xref target="exclusive_create" format="default"/> in <xref target
	target="OP_OPEN_DESCRIPTION" /> summarizes how a client		="OP_OPEN_DESCRIPTION" format="default"/> summarizes how a client
	is allowed to send an exclusive create.		is allowed to send an exclusive create.
	</t>		</t>
	</section>		</section>
			<section anchor="layout_stateid" numbered="true" toc="default">
	<section title="Layout Stateid" anchor="layout_stateid">		<name>Layout Stateid</name>
	<t>		<t>
	As with all other stateids, the layout stateid consists of a "seqid" and		As with all other stateids, the layout stateid consists of a "seqid" and
	"other" field. Once a layout stateid is established, the "other" field		"other" field. Once a layout stateid is established, the "other" field
	will stay constant unless the stateid is revoked or the client		will stay constant unless the stateid is revoked or the client
	returns all layouts on the file and the server disposes of the		returns all layouts on the file and the server disposes of the
	stateid. The "seqid" field is initially set to one, and is never		stateid. The "seqid" field is initially set to one, and is never
	zero on any NFSv4.1 operation that uses layout stateids, whether it		zero on any NFSv4.1 operation that uses layout stateids, whether it
	is a fore channel or backchannel operation. After the layout stateid		is a fore channel or backchannel operation. After the layout stateid
	is established, the server increments by one the value of the		is established, the server increments by one the value of the
	"seqid" in each subsequent LAYOUTGET and LAYOUTRETURN response, and		"seqid" in each subsequent LAYOUTGET and LAYOUTRETURN response, and
	in each CB_LAYOUTRECALL request.		in each CB_LAYOUTRECALL request.
	</t>		</t>
	<t>		<t>
	Given the design goal of pNFS to provide parallelism, the layout		Given the design goal of pNFS to provide parallelism, the layout
	stateid differs from other stateid types in that the client is		stateid differs from other stateid types in that the client is
	expected to send LAYOUTGET and LAYOUTRETURN operations in parallel.		expected to send LAYOUTGET and LAYOUTRETURN operations in parallel.
	The "seqid" value is used by the client to properly sort responses		The "seqid" value is used by the client to properly sort responses
	to LAYOUTGET and LAYOUTRETURN. The "seqid" is also used to prevent		to LAYOUTGET and LAYOUTRETURN. The "seqid" is also used to prevent
	race conditions between LAYOUTGET and CB_LAYOUTRECALL. Given that the		race conditions between LAYOUTGET and CB_LAYOUTRECALL. Given that the
	processing rules differ from layout stateids and other stateid		processing rules differ from layout stateids and other stateid
	types, only the pNFS sections of this document should be considered		types, only the pNFS sections of this document should be considered
	to determine proper layout stateid handling.		to determine proper layout stateid handling.
	</t>		</t>
	<t>		<t>
	Once the client receives a layout stateid, it MUST use the correct		Once the client receives a layout stateid, it <bcp14>MUST</bcp14> use the corr
			ect
	"seqid" for subsequent LAYOUTGET or LAYOUTRETURN operations. The		"seqid" for subsequent LAYOUTGET or LAYOUTRETURN operations. The
	correct "seqid" is defined as the highest "seqid" value from		correct "seqid" is defined as the highest "seqid" value from
	responses of fully processed LAYOUTGET or LAYOUTRETURN operations or		responses of fully processed LAYOUTGET or LAYOUTRETURN operations or
	arguments of a fully processed CB_LAYOUTRECALL operation. Since the		arguments of a fully processed CB_LAYOUTRECALL operation. Since the
	server is incrementing the "seqid" value on each layout operation,		server is incrementing the "seqid" value on each layout operation,
	the client may determine the order of operation processing by		the client may determine the order of operation processing by
	inspecting the "seqid" value. In the case of overlapping layout		inspecting the "seqid" value. In the case of overlapping layout
	ranges, the ordering information will provide the client the		ranges, the ordering information will provide the client the
	knowledge of which layout ranges are held. Note that overlapping		knowledge of which layout ranges are held. Note that overlapping
	layout ranges may occur because of the client's specific requests or		layout ranges may occur because of the client's specific requests or
	because the server is allowed to expand the range of a requested		because the server is allowed to expand the range of a requested
	layout and notify the client in the LAYOUTRETURN results. Additional		layout and notify the client in the LAYOUTRETURN results. Additional
	layout stateid sequencing requirements are provided in		layout stateid sequencing requirements are provided in
	<xref target="pnfs_operation_sequencing"/>.		<xref target="pnfs_operation_sequencing" format="default"/>.
	</t>		</t>
	<t>		<t>
	The client's receipt of a "seqid" is not sufficient for subsequent		The client's receipt of a "seqid" is not sufficient for subsequent
	use. The client must fully process the operations before the		use. The client must fully process the operations before the
	"seqid" can be used. For LAYOUTGET results, if		"seqid" can be used. For LAYOUTGET results, if
	the client is not using the forgetful model		the client is not using the forgetful model
	(<xref target="recall_robustness"/>), it MUST first update its		(<xref target="recall_robustness" format="default"/>), it <bcp14>MUST</bcp14> first update its
	record of what ranges of the file's layout it has before using the		record of what ranges of the file's layout it has before using the
	seqid. For LAYOUTRETURN results, the client MUST delete the range		seqid. For LAYOUTRETURN results, the client <bcp14>MUST</bcp14> delete the ran ge
	from its record of what ranges of the file's layout it had before		from its record of what ranges of the file's layout it had before
	using the seqid. For CB_LAYOUTRECALL arguments, the client MUST send		using the seqid. For CB_LAYOUTRECALL arguments, the client <bcp14>MUST</bcp14> send
	a response to the recall before using the seqid.		a response to the recall before using the seqid.
	The fundamental requirement in client		The fundamental requirement in client
	processing is that the "seqid" is used to provide the order of		processing is that the "seqid" is used to provide the order of
	processing. LAYOUTGET results may be processed in parallel.		processing. LAYOUTGET results may be processed in parallel.
	LAYOUTRETURN results may be processed in parallel. LAYOUTGET and		LAYOUTRETURN results may be processed in parallel. LAYOUTGET and
	LAYOUTRETURN responses may be processed in parallel as long as the		LAYOUTRETURN responses may be processed in parallel as long as the
	ranges do not overlap. CB_LAYOUTRECALL request processing MUST be		ranges do not overlap. CB_LAYOUTRECALL request processing <bcp14>MUST</bcp14> be
	processed in "seqid" order at all times.		processed in "seqid" order at all times.
	</t>		</t>
	<t>		<t>
	Once a client has no more layouts on a file, the layout stateid is		Once a client has no more layouts on a file, the layout stateid is
	no longer valid and MUST NOT be used. Any attempt to use such a		no longer valid and <bcp14>MUST NOT</bcp14> be used. Any attempt to use such a
	layout stateid will result in NFS4ERR_BAD_STATEID.		layout stateid will result in NFS4ERR_BAD_STATEID.
	</t>		</t>
			</section>
	</section>		<section anchor="committing_layout" numbered="true" toc="default">
			<name>Committing a Layout</name>
	<section title="Committing a Layout" anchor="committing_layout">		<t>
	<t>
	Allowing for varying storage protocol capabilities, the pNFS		Allowing for varying storage protocol capabilities, the pNFS
	protocol does not require the metadata server and storage devices to		protocol does not require the metadata server and storage devices to
	have a consistent view of file attributes and data location		have a consistent view of file attributes and data location
	mappings. Data location mapping refers to aspects such as which offsets		mappings. Data location mapping refers to aspects such as which offsets
	store data as opposed to storing holes (see <xref		store data as opposed to storing holes (see <xref target="sparse_dense" format
	target="sparse_dense" /> for a discussion). Related issues arise		="default"/> for a discussion). Related issues arise
	for storage protocols where a layout may hold provisionally		for storage protocols where a layout may hold provisionally
	allocated blocks where the allocation of those blocks does not		allocated blocks where the allocation of those blocks does not
	survive a complete restart of both the client and server. Because		survive a complete restart of both the client and server. Because
	of this inconsistency, it is necessary to resynchronize the client		of this inconsistency, it is necessary to resynchronize the client
	with the metadata server and its storage devices and make any		with the metadata server and its storage devices and make any
	potential changes available to other clients. This is accomplished		potential changes available to other clients. This is accomplished
	by use of the LAYOUTCOMMIT operation.		by use of the LAYOUTCOMMIT operation.
	</t>		</t>
	<t>		<t>
	The LAYOUTCOMMIT operation is responsible for committing a modified		The LAYOUTCOMMIT operation is responsible for committing a modified
	layout to the metadata server. The data should be written		layout to the metadata server. The data should be written
	and committed to the appropriate storage devices before the		and committed to the appropriate storage devices before the
	LAYOUTCOMMIT occurs. The		LAYOUTCOMMIT occurs. The
	scope of the LAYOUTCOMMIT operation depends on the storage protocol		scope of the LAYOUTCOMMIT operation depends on the storage protocol
	in use. It is important to note that the level of		in use. It is important to note that the level of
	synchronization is from the point of view of the client that sent		synchronization is from the point of view of the client that sent
	the LAYOUTCOMMIT. The updated state on the metadata server need		the LAYOUTCOMMIT. The updated state on the metadata server need
	only reflect the state as of the client's last operation previous to		only reflect the state as of the client's last operation previous to
	the LAYOUTCOMMIT. The metadata server is not REQUIRED to maintain a global vi ew		the LAYOUTCOMMIT. The metadata server is not <bcp14>REQUIRED</bcp14> to maint ain a global view
	that accounts for other clients' I/O that may have occurred within		that accounts for other clients' I/O that may have occurred within
	the same time frame.		the same time frame.
	</t>		</t>
	<t>		<t>
	For block/volume-based layouts, LAYOUTCOMMIT may require		For block/volume-based layouts, LAYOUTCOMMIT may require
	updating the block list that comprises the file and committing this		updating the block list that comprises the file and committing this
	layout to stable storage. For file-based layouts, synchronization of		layout to stable storage. For file-based layouts, synchronization of
	attributes between the metadata and storage devices, primarily the		attributes between the metadata and storage devices, primarily the
	size attribute, is required.		size attribute, is required.
	</t>		</t>
	<t>		<t>
	The control protocol is free to synchronize the attributes before		The control protocol is free to synchronize the attributes before
	it receives a LAYOUTCOMMIT; however, upon successful completion of a		it receives a LAYOUTCOMMIT; however, upon successful completion of a
	LAYOUTCOMMIT, state that exists on the metadata server that		LAYOUTCOMMIT, state that exists on the metadata server that
	describes the file MUST be synchronized with the state that exists on the		describes the file <bcp14>MUST</bcp14> be synchronized with the state that exi sts on the
	storage devices that comprise that file as of the client's		storage devices that comprise that file as of the client's
	last sent operation. Thus, a client that queries the size of a file		last sent operation. Thus, a client that queries the size of a file
	between a WRITE to a storage device and the LAYOUTCOMMIT might observe		between a WRITE to a storage device and the LAYOUTCOMMIT might observe
	a size that does not reflect the actual data written.		a size that does not reflect the actual data written.
	</t>		</t>
			<t>
	<t>		The client <bcp14>MUST</bcp14> have a layout in order to send a LAYOUTCOMMIT o
	The client MUST have a layout in order to send a LAYOUTCOMMIT operation.		peration.
	</t>		</t>
			<section numbered="true" toc="default">
	<section title="LAYOUTCOMMIT and change/time_modify">		<name>LAYOUTCOMMIT and change/time_modify</name>
	<t>		<t>
	The change and time_modify attributes may be updated		The change and time_modify attributes may be updated
	by the server when the LAYOUTCOMMIT operation is processed. The		by the server when the LAYOUTCOMMIT operation is processed. The
	reason for this is that some layout types do not support the update		reason for this is that some layout types do not support the update
	of these attributes when the storage devices process I/O operations.		of these attributes when the storage devices process I/O operations.
	If a client has a layout with the LAYOUTIOMODE4_RW iomode on the file,		If a client has a layout with the LAYOUTIOMODE4_RW iomode on the file,
	the client MAY provide a suggested value to the server for		the client <bcp14>MAY</bcp14> provide a suggested value to the server for
	time_modify within the arguments to LAYOUTCOMMIT.		time_modify within the arguments to LAYOUTCOMMIT.
	Based on the layout type, the provided value may or may not be used.		Based on the layout type, the provided value may or may not be used.
	The server should sanity-check the client-provided values		The server should sanity-check the client-provided values
	before they are used. For example, the server should ensure that		before they are used. For example, the server should ensure that
	time does not flow backwards. The client always has the option to		time does not flow backwards. The client always has the option to
	set time_modify through an explicit SETATTR operation.		set time_modify through an explicit SETATTR operation.
	</t>		</t>
	<t>		<t>
	For some layout protocols, the storage device is able to notify the		For some layout protocols, the storage device is able to notify the
	metadata server of the occurrence of an I/O; as a result, the		metadata server of the occurrence of an I/O; as a result, the
	change and time_modify attributes may be updated at		change and time_modify attributes may be updated at
	the metadata server. For a metadata server that is capable of		the metadata server. For a metadata server that is capable of
	monitoring updates to the change and time_modify		monitoring updates to the change and time_modify
	attributes, LAYOUTCOMMIT processing is not required to update the		attributes, LAYOUTCOMMIT processing is not required to update the
	change attribute. In this case, the metadata server must ensure that		change attribute. In this case, the metadata server must ensure that
	no further update to the data has occurred since the last update of		no further update to the data has occurred since the last update of
	the attributes; file-based protocols may have enough information to		the attributes; file-based protocols may have enough information to
	make this determination or may update the change attribute upon each		make this determination or may update the change attribute upon each
	file modification. This also applies for the time_modify		file modification. This also applies for the time_modify
	attribute. If the server implementation is able to		attribute. If the server implementation is able to
	determine that the file has not been modified since the last		determine that the file has not been modified since the last
	time_modify update, the server need not update time_modify at		time_modify update, the server need not update time_modify at
	LAYOUTCOMMIT. At LAYOUTCOMMIT completion, the updated attributes		LAYOUTCOMMIT. At LAYOUTCOMMIT completion, the updated attributes
	should be visible if that file was modified since the latest		should be visible if that file was modified since the latest
	previous LAYOUTCOMMIT or LAYOUTGET.		previous LAYOUTCOMMIT or LAYOUTGET.
	</t>		</t>
	</section>		</section>
	<section title="LAYOUTCOMMIT and size" anchor="general_layoutcommit">		<section anchor="general_layoutcommit" numbered="true" toc="default">
	<t>		<name>LAYOUTCOMMIT and size</name>
			<t>
	The size of a file may be updated when the LAYOUTCOMMIT operation is		The size of a file may be updated when the LAYOUTCOMMIT operation is
	used by the client. One of the fields in the argument to		used by the client. One of the fields in the argument to
	LAYOUTCOMMIT is loca_last_write_offset; this field indicates the		LAYOUTCOMMIT is loca_last_write_offset; this field indicates the
	highest byte offset written but not yet committed with the		highest byte offset written but not yet committed with the
	LAYOUTCOMMIT operation. The data type of loca_last_write_offset is		LAYOUTCOMMIT operation. The data type of loca_last_write_offset is
	newoffset4 and is switched on a boolean value, no_newoffset, that		newoffset4 and is switched on a boolean value, no_newoffset, that
	indicates if a previous write occurred or not. If no_newoffset is		indicates if a previous write occurred or not. If no_newoffset is
	FALSE, an offset is not given. If the client has a layout with		FALSE, an offset is not given. If the client has a layout with
	LAYOUTIOMODE4_RW iomode on the file, with a byte-range (denoted by the values of lo_offset and lo_length)		LAYOUTIOMODE4_RW iomode on the file, with a byte-range (denoted by the values of lo_offset and lo_length)
	that overlaps loca_last_write_offset, then the client MAY		that overlaps loca_last_write_offset, then the client <bcp14>MAY</bcp14>
	set no_newoffset to TRUE and provide an offset that will		set no_newoffset to TRUE and provide an offset that will
	update the file size. Keep in mind that offset is not the same		update the file size. Keep in mind that offset is not the same
	as length, though they are related. For example, a loca_last_write_offset		as length, though they are related. For example, a loca_last_write_offset
	value of zero means that one byte was written at offset zero, and so		value of zero means that one byte was written at offset zero, and so
	the length of the file is at least one byte.		the length of the file is at least one byte.
	</t>		</t>
	<t>		<t>
	The metadata server may do one of the following:		The metadata server may do one of the following:
	<list style="numbers">		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	Update the file's size using the last write offset provided by		Update the file's size using the last write offset provided by
	the client as either the true file size or as a hint of the file		the client as either the true file size or as a hint of the file
	size. If the metadata server has a method available, any new		size. If the metadata server has a method available, any new
	value for file size should be sanity-checked. For example, the		value for file size should be sanity-checked. For example, the
	file must not be truncated if the client presents a last write		file must not be truncated if the client presents a last write
	offset less than the file's current size.		offset less than the file's current size.
	</t>		</li>
	<t>		<li>
	Ignore the client-provided last write offset; the metadata		Ignore the client-provided last write offset; the metadata
	server must have sufficient knowledge from other sources to		server must have sufficient knowledge from other sources to
	determine the file's size. For example, the metadata server		determine the file's size. For example, the metadata server
	queries the storage devices with the control protocol.		queries the storage devices with the control protocol.
	</t>		</li>
	</list>		</ol>
	</t>		<t>
	<t>
	The method chosen to update the file's size will depend on the		The method chosen to update the file's size will depend on the
	storage device's and/or the control protocol's capabilities. For		storage device's and/or the control protocol's capabilities. For
	example, if the storage devices are block devices with no knowledge		example, if the storage devices are block devices with no knowledge
	of file size, the metadata server must rely on the client to set the		of file size, the metadata server must rely on the client to set the
	last write offset appropriately.		last write offset appropriately.
	</t>		</t>
	<t>		<t>
	The results of LAYOUTCOMMIT contain a new size value in the form of		The results of LAYOUTCOMMIT contain a new size value in the form of
	a newsize4 union data type. If the file's size is set as a result		a newsize4 union data type. If the file's size is set as a result
	of LAYOUTCOMMIT, the metadata server must reply with the new size;		of LAYOUTCOMMIT, the metadata server must reply with the new size;
	otherwise, the new size is not provided.		otherwise, the new size is not provided.
	If the file size is updated, the metadata server SHOULD update the		If the file size is updated, the metadata server <bcp14>SHOULD</bcp14> update the
	storage devices such that the new file size is reflected when		storage devices such that the new file size is reflected when
	LAYOUTCOMMIT processing is complete. For example, the client should		LAYOUTCOMMIT processing is complete. For example, the client should
	be able to read up to the new file size.		be able to read up to the new file size.
	</t>		</t>
	<t>		<t>
	The client can extend the length of a file		The client can extend the length of a file
	or truncate a file by sending a SETATTR operation to the metadata server		or truncate a file by sending a SETATTR operation to the metadata server
	with the size attribute specified. If the size specified is larger than		with the size attribute specified. If the size specified is larger than
	the current size of the file, the file is "zero extended", i.e., zeros are		the current size of the file, the file is "zero extended", i.e., zeros are
	implicitly added between the file's previous EOF and the new EOF.		implicitly added between the file's previous EOF and the new EOF.
	(In many implementations, the zero-extended byte-range		(In many implementations, the zero-extended byte-range
	of the file consists of unallocated		of the file consists of unallocated
	holes in the file.) When the client writes past EOF via WRITE,		holes in the file.) When the client writes past EOF via WRITE,
	the SETATTR operation does not need to be used.		the SETATTR operation does not need to be used.
	</t>		</t>
	</section>		</section>
	<section title="LAYOUTCOMMIT and layoutupdate" anchor="layoutcommit_update">		<section anchor="layoutcommit_update" numbered="true" toc="default">
	<t>		<name>LAYOUTCOMMIT and layoutupdate</name>
	The LAYOUTCOMMIT argument contains a loca_layoutupdate field (<xref		<t>
	target="OP_LAYOUTCOMMIT_ARGUMENT"/>) of data type layoutupdate4		The LAYOUTCOMMIT argument contains a loca_layoutupdate field (<xref target="OP
	(<xref target="layoutupdate4"/>). This argument is a		_LAYOUTCOMMIT_ARGUMENT" format="default"/>) of data type layoutupdate4
			(<xref target="layoutupdate4" format="default"/>). This argument is a
	layout-type-specific structure. The structure can be used to pass		layout-type-specific structure. The structure can be used to pass
	arbitrary layout-type-specific information from the client to the		arbitrary layout-type-specific information from the client to the
	metadata server at LAYOUTCOMMIT time. For example, if using a		metadata server at LAYOUTCOMMIT time. For example, if using a
	block/volume layout, the client can indicate to the metadata server		block/volume layout, the client can indicate to the metadata server
	which reserved or allocated blocks the client used or did not use.		which reserved or allocated blocks the client used or did not use.
	The content of loca_layoutupdate (field lou_body) need not be the		The content of loca_layoutupdate (field lou_body) need not be the
	same layout-type-specific content returned by LAYOUTGET (<xref		same layout-type-specific content returned by LAYOUTGET (<xref target="OP_LAYO
	target="OP_LAYOUTGET_RESULT" />) in the loc_body field of the		UTGET_RESULT" format="default"/>) in the loc_body field of the
	lo_content field of the logr_layout field.		lo_content field of the logr_layout field.
	The content of		The content of
	loca_layoutupdate is defined by the layout type specification and is		loca_layoutupdate is defined by the layout type specification and is
	opaque to LAYOUTCOMMIT.		opaque to LAYOUTCOMMIT.
	</t>		</t>
	</section>		</section>
	</section> <!-- Layout Semantics -->		</section>
	<section title="Recalling a Layout" anchor="recalling_layout">		<section anchor="recalling_layout" numbered="true" toc="default">
	<t>		<name>Recalling a Layout</name>
			<t>
	Since a layout protects a client's access to a file via a direct		Since a layout protects a client's access to a file via a direct
	client-storage-device path, a layout need only be recalled when it		client-storage-device path, a layout need only be recalled when it
	is semantically unable to serve this function. Typically, this		is semantically unable to serve this function. Typically, this
	occurs when the layout no longer encapsulates the true location of		occurs when the layout no longer encapsulates the true location of
	the file over the byte-range it represents. Any operation or		the file over the byte-range it represents. Any operation or
	action, such as server-driven restriping or load balancing, that		action, such as server-driven restriping or load balancing, that
	changes the layout will result in a recall of the layout. A layout		changes the layout will result in a recall of the layout. A layout
	is recalled by the CB_LAYOUTRECALL callback operation (see <xref		is recalled by the CB_LAYOUTRECALL callback operation (see <xref target="OP_CB
	target="OP_CB_LAYOUTRECALL" />) and returned with LAYOUTRETURN (see <xref		_LAYOUTRECALL" format="default"/>) and returned with LAYOUTRETURN (see <xref tar
	target="OP_LAYOUTRETURN" />). The CB_LAYOUTRECALL operation may		get="OP_LAYOUTRETURN" format="default"/>). The CB_LAYOUTRECALL operation may
	recall a layout identified by a byte-range, all layouts		recall a layout identified by a byte-range, all layouts
	associated with a file system ID (FSID), or all layouts associated with		associated with a file system ID (FSID), or all layouts associated with
	a client ID.		a client ID.
	<xref target="pnfs_operation_sequencing" /> discusses sequencing issues		<xref target="pnfs_operation_sequencing" format="default"/> discusses sequenci ng issues
	surrounding the getting, returning, and recalling of layouts.		surrounding the getting, returning, and recalling of layouts.
	</t>		</t>
	<t>		<t>
	An iomode is also specified when recalling a layout.		An iomode is also specified when recalling a layout.
	Generally, the iomode in the recall request must match the layout		Generally, the iomode in the recall request must match the layout
	being returned; for example, a recall with an iomode of		being returned; for example, a recall with an iomode of
	LAYOUTIOMODE4_RW should cause the client to only return		LAYOUTIOMODE4_RW should cause the client to only return
	LAYOUTIOMODE4_RW layouts and not LAYOUTIOMODE4_READ layouts.		LAYOUTIOMODE4_RW layouts and not LAYOUTIOMODE4_READ layouts.
	However, a special LAYOUTIOMODE4_ANY enumeration is		However, a special LAYOUTIOMODE4_ANY enumeration is
	defined to enable recalling a layout of any iomode; in other words,		defined to enable recalling a layout of any iomode; in other words,
	the client must return both LAYOUTIOMODE4_READ and LAYOUTIOMODE4_RW layouts.		the client must return both LAYOUTIOMODE4_READ and LAYOUTIOMODE4_RW layouts.
	</t>		</t>
	<t>		<t>
	A REMOVE operation SHOULD cause the metadata server to recall the		A REMOVE operation <bcp14>SHOULD</bcp14> cause the metadata server to recall t
			he
	layout to prevent the client from accessing a non-existent file and		layout to prevent the client from accessing a non-existent file and
	to reclaim state stored on the client. Since a REMOVE may be delayed		to reclaim state stored on the client. Since a REMOVE may be delayed
	until the last close of the file has occurred, the recall may also		until the last close of the file has occurred, the recall may also
	be delayed until this time. After the last reference on the file		be delayed until this time. After the last reference on the file
	has been released and the file has been removed, the client should		has been released and the file has been removed, the client should
	no longer be able to perform I/O using the layout. In the case of a		no longer be able to perform I/O using the layout. In the case of a
	file-based layout, the data server SHOULD return NFS4ERR_STALE in		file-based layout, the data server <bcp14>SHOULD</bcp14> return NFS4ERR_STALE in
	response to any operation on the removed file.		response to any operation on the removed file.
	</t>		</t>
	<t>		<t>
	Once a layout has been returned, the client MUST NOT send I/Os to		Once a layout has been returned, the client <bcp14>MUST NOT</bcp14> send I/Os
			to
	the storage devices for the file, byte-range, and iomode		the storage devices for the file, byte-range, and iomode
	represented by the returned layout. If a client does send an I/O to		represented by the returned layout. If a client does send an I/O to
	a storage device for which it does not hold a layout, the storage		a storage device for which it does not hold a layout, the storage
	device SHOULD reject the I/O.		device <bcp14>SHOULD</bcp14> reject the I/O.
	</t>		</t>
	<t anchor="pnfs_and_delegations">		<t anchor="pnfs_and_delegations">
	Although pNFS does not alter the file data caching capabilities of		Although pNFS does not alter the file data caching capabilities of
	clients, or their semantics, it recognizes that some clients may		clients, or their semantics, it recognizes that some clients may
	perform more aggressive write-behind caching to optimize the		perform more aggressive write-behind caching to optimize the
	benefits provided by pNFS. However, write-behind caching may		benefits provided by pNFS. However, write-behind caching may
	negatively affect the latency in returning a layout in response to a		negatively affect the latency in returning a layout in response to a
	CB_LAYOUTRECALL; this is similar to file delegations and the impact		CB_LAYOUTRECALL; this is similar to file delegations and the impact
	that file data caching has on DELEGRETURN. Client implementations		that file data caching has on DELEGRETURN. Client implementations
	SHOULD limit the amount of unwritten data they have outstanding at		<bcp14>SHOULD</bcp14> limit the amount of unwritten data they have outstanding at
	any one time in order to prevent excessively long responses to		any one time in order to prevent excessively long responses to
	CB_LAYOUTRECALL. Once a layout is recalled, a server MUST wait one		CB_LAYOUTRECALL. Once a layout is recalled, a server <bcp14>MUST</bcp14> wait one
	lease period before taking further action. As soon as a lease		lease period before taking further action. As soon as a lease
	period has passed, the server may choose to fence the client's access		period has passed, the server may choose to fence the client's access
	to the storage devices if the server perceives the client has taken		to the storage devices if the server perceives the client has taken
	too long to return a layout. However, just as in the case of data		too long to return a layout. However, just as in the case of data
	delegation and DELEGRETURN, the server may choose to wait, given that		delegation and DELEGRETURN, the server may choose to wait, given that
	the client is showing forward progress on its way to returning the		the client is showing forward progress on its way to returning the
	layout. This forward progress can take the form of successful		layout. This forward progress can take the form of successful
	interaction with the storage devices or of sub-portions of the layout		interaction with the storage devices or of sub-portions of the layout
	being returned by the client. The server can also limit exposure to		being returned by the client. The server can also limit exposure to
	these problems by limiting the byte-ranges initially provided in		these problems by limiting the byte-ranges initially provided in
	the layouts and thus the amount of outstanding modified data.		the layouts and thus the amount of outstanding modified data.
	</t>		</t>
			<section anchor="recall_robustness" numbered="true" toc="default">
	<section title="Layout Recall Callback Robustness" anchor="recall_robustness">		<name>Layout Recall Callback Robustness</name>
	<t>		<t>
	It has been assumed thus far that pNFS client		It has been assumed thus far that pNFS client
	state		state
	(layout ranges and iomode)		(layout ranges and iomode)
	for a file exactly matches that of the pNFS server for that file.		for a file exactly matches that of the pNFS server for that file.
	This assumption		This assumption
	leads to the implication that any callback results in a		leads to the implication that any callback results in a
	LAYOUTRETURN or set of LAYOUTRETURNs that exactly match the range in		LAYOUTRETURN or set of LAYOUTRETURNs that exactly match the range in
	the callback, since both client and server agree about the state		the callback, since both client and server agree about the state
	being maintained. However, it can be useful if this assumption does		being maintained. However, it can be useful if this assumption does
	not always hold. For example:		not always hold. For example:
	</t>		</t>
	<t>		<ul spacing="normal">
	<list style="symbols">		<li>
	<t>
	If conflicts that require		If conflicts that require
	callbacks are very rare, and a server can use a multi-file callback		callbacks are very rare, and a server can use a multi-file callback
	to recover per-client resources (e.g., via an FSID recall or a		to recover per-client resources (e.g., via an FSID recall or a
	multi-file recall within a single CB_COMPOUND), the result may be		multi-file recall within a single CB_COMPOUND), the result may be
	significantly less client-server pNFS traffic.		significantly less client-server pNFS traffic.
	</t>		</li>
	<t>		<li>
	It may be useful for servers to maintain information about		It may be useful for servers to maintain information about
	what ranges are held by a client on a coarse-grained basis, leading		what ranges are held by a client on a coarse-grained basis, leading
	to the server's layout ranges being beyond those actually held by		to the server's layout ranges being beyond those actually held by
	the client.		the client.
	In the extreme, a server could manage conflicts on		In the extreme, a server could manage conflicts on
	a per-file basis, only sending whole-file callbacks even though		a per-file basis, only sending whole-file callbacks even though
	clients may request and be granted sub-file ranges.		clients may request and be granted sub-file ranges.
	</t>		</li>
	<t>		<li>
	It may be useful for clients to "forget" details about		It may be useful for clients to "forget" details about
	what layouts and ranges the client actually has, leading		what layouts and ranges the client actually has, leading
	to the server's layout ranges being beyond those that the		to the server's layout ranges being beyond those that the
	client "thinks" it has. As long as the client does not		client "thinks" it has. As long as the client does not
	assume it has layouts that are beyond what the server		assume it has layouts that are beyond what the server
	has granted, this is a safe practice. When a client		has granted, this is a safe practice. When a client
	forgets what ranges and layouts it has, and it receives		forgets what ranges and layouts it has, and it receives
	a CB_LAYOUTRECALL operation, the client MUST follow up		a CB_LAYOUTRECALL operation, the client <bcp14>MUST</bcp14> follow up
	with a LAYOUTRETURN for what the server recalled, or		with a LAYOUTRETURN for what the server recalled, or
	alternatively return the NFS4ERR_NOMATCHING_LAYOUT error		alternatively return the NFS4ERR_NOMATCHING_LAYOUT error
	if it has no layout to return in the recalled range.		if it has no layout to return in the recalled range.
	</t>		</li>
			<li>
	<t>
	In order to avoid errors, it is vital that a client not assign		In order to avoid errors, it is vital that a client not assign
	itself layout permissions beyond what the server has granted, and		itself layout permissions beyond what the server has granted, and
	that the server not forget layout permissions that have been granted.		that the server not forget layout permissions that have been granted.
	On the other hand, if a		On the other hand, if a
	server believes that a client holds a layout that the client		server believes that a client holds a layout that the client
	does not know about, it is useful for the client to cleanly indicate		does not know about, it is useful for the client to cleanly indicate
	completion of the requested recall either by sending a LAYOUTRETURN		completion of the requested recall either by sending a LAYOUTRETURN
	operation for the entire requested range or by returning an		operation for the entire requested range or by returning an
	NFS4ERR_NOMATCHING_LAYOUT error to the CB_LAYOUTRECALL.		NFS4ERR_NOMATCHING_LAYOUT error to the CB_LAYOUTRECALL.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Thus, in light of the above, it is useful for a server to be able to		Thus, in light of the above, it is useful for a server to be able to
	send callbacks for layout ranges it has not granted to a client,		send callbacks for layout ranges it has not granted to a client,
	and for a client to return ranges it does not hold. A pNFS client		and for a client to return ranges it does not hold. A pNFS client
	MUST always return layouts that comprise the full range		<bcp14>MUST</bcp14> always return layouts that comprise the full range
	specified by the recall. Note, the full recalled layout range need		specified by the recall. Note, the full recalled layout range need
	not be returned as part of a single operation, but may be returned		not be returned as part of a single operation, but may be returned
	in portions. This allows the client to stage the flushing of dirty		in portions. This allows the client to stage the flushing of dirty
	data and commits and returns of layouts.		data and commits and returns of layouts.
	Also, it indicates to the		Also, it indicates to the
	metadata server that the client is making progress.		metadata server that the client is making progress.
	</t>		</t>
	<t>		<t>
	When a layout is returned, the client MUST NOT have any outstanding		When a layout is returned, the client <bcp14>MUST NOT</bcp14> have any outstan
			ding
	I/O requests to the storage devices involved in the layout.		I/O requests to the storage devices involved in the layout.
	Rephrasing, the client MUST NOT return the layout while it has		Rephrasing, the client <bcp14>MUST NOT</bcp14> return the layout while it has
	outstanding I/O requests to the storage device.		outstanding I/O requests to the storage device.
	</t>		</t>
	<t>		<t>
	Even with this requirement for the client, it is possible that I/O		Even with this requirement for the client, it is possible that I/O
	requests may be presented to a storage device no longer allowed to		requests may be presented to a storage device no longer allowed to
	perform them. Since the server has no strict control as to when the		perform them. Since the server has no strict control as to when the
	client will return the layout, the server may later decide to		client will return the layout, the server may later decide to
	unilaterally revoke the client's access to the storage devices		unilaterally revoke the client's access to the storage devices
	as provided by the layout. In		as provided by the layout. In
	choosing to revoke access, the server must deal with the possibility		choosing to revoke access, the server must deal with the possibility
	of lingering I/O requests, i.e., I/O requests that are		of lingering I/O requests, i.e., I/O requests that are
	still in flight to		still in flight to
	storage devices identified by the revoked layout.		storage devices identified by the revoked layout.
	All layout type specifications MUST define whether unilateral layout revocatio n by		All layout type specifications <bcp14>MUST</bcp14> define whether unilateral l ayout revocation by
	the metadata server is supported; if it is, the specification must		the metadata server is supported; if it is, the specification must
	also describe how lingering writes are processed. For example,		also describe how lingering writes are processed. For example,
	storage devices identified by the revoked layout could be fenced off		storage devices identified by the revoked layout could be fenced off
	from the client that held the layout.		from the client that held the layout.
	</t>		</t>
	<t>		<t>
	In order to ensure client/server convergence with regard to layout state,		In order to ensure client/server convergence with regard to layout state,
	the final LAYOUTRETURN operation in a sequence of LAYOUTRETURN		the final LAYOUTRETURN operation in a sequence of LAYOUTRETURN
	operations for a particular recall MUST specify the entire range		operations for a particular recall <bcp14>MUST</bcp14> specify the entire rang e
	being recalled, echoing the recalled layout type, iomode,		being recalled, echoing the recalled layout type, iomode,
	recall/return type (FILE, FSID, or ALL), and byte-range, even if		recall/return type (FILE, FSID, or ALL), and byte-range, even if
	layouts pertaining to partial ranges were previously		layouts pertaining to partial ranges were previously
	returned. In addition, if the client holds no layouts that		returned. In addition, if the client holds no layouts that
	overlap the range being recalled, the client should return the		overlap the range being recalled, the client should return the
	NFS4ERR_NOMATCHING_LAYOUT error code to CB_LAYOUTRECALL. This		NFS4ERR_NOMATCHING_LAYOUT error code to CB_LAYOUTRECALL. This
	allows the server to update its view of the client's layout state.		allows the server to update its view of the client's layout state.
	</t>		</t>
	</section>		</section>
			<section anchor="pnfs_operation_sequencing" numbered="true" toc="defau
	<section title="Sequencing of Layout Operations" anchor="pnfs_operation_sequenci		lt">
	ng">		<name>Sequencing of Layout Operations</name>
	<t>		<t>
	As with other stateful operations, pNFS requires the correct		As with other stateful operations, pNFS requires the correct
	sequencing of layout operations. pNFS uses the "seqid" in the		sequencing of layout operations. pNFS uses the "seqid" in the
	layout stateid to provide the correct sequencing between regular		layout stateid to provide the correct sequencing between regular
	operations and callbacks. It is the server's responsibility to		operations and callbacks. It is the server's responsibility to
	avoid inconsistencies regarding the layouts provided and the		avoid inconsistencies regarding the layouts provided and the
	client's responsibility to properly serialize its layout requests		client's responsibility to properly serialize its layout requests
	and layout returns.		and layout returns.
	</t>		</t>
	<section title="Layout Recall and Return Sequencing">		<section numbered="true" toc="default">
	<t>		<name>Layout Recall and Return Sequencing</name>
			<t>
	One critical issue with regard to layout operations sequencing		One critical issue with regard to layout operations sequencing
	concerns callbacks. The protocol must defend against		concerns callbacks. The protocol must defend against
	races between the reply to a LAYOUTGET or LAYOUTRETURN		races between the reply to a LAYOUTGET or LAYOUTRETURN
	operation and a subsequent CB_LAYOUTRECALL. A client		operation and a subsequent CB_LAYOUTRECALL. A client
	MUST NOT process a CB_LAYOUTRECALL that implies one or		<bcp14>MUST NOT</bcp14> process a CB_LAYOUTRECALL that implies one or
	more outstanding LAYOUTGET or LAYOUTRETURN operations to		more outstanding LAYOUTGET or LAYOUTRETURN operations to
	which the client has not yet received a reply. The client		which the client has not yet received a reply. The client
	detects such a CB_LAYOUTRECALL by examining the "seqid"		detects such a CB_LAYOUTRECALL by examining the "seqid"
	field of the recall's layout stateid. If the "seqid"		field of the recall's layout stateid. If the "seqid"
	is not exactly one higher than what the client currently has recorded, and the		is not exactly one higher than what the client currently has recorded, and the
	client has at least one LAYOUTGET and/or LAYOUTRETURN operation		client has at least one LAYOUTGET and/or LAYOUTRETURN operation
	outstanding, the client knows the server sent the CB_LAYOUTRECALL		outstanding, the client knows the server sent the CB_LAYOUTRECALL
	after sending a response to an outstanding LAYOUTGET or LAYOUTRETURN.		after sending a response to an outstanding LAYOUTGET or LAYOUTRETURN.
	The client MUST wait before processing such a CB_LAYOUTRECALL		The client <bcp14>MUST</bcp14> wait before processing such a CB_LAYOUTRECALL
	until it processes all replies for outstanding LAYOUTGET and		until it processes all replies for outstanding LAYOUTGET and
	LAYOUTRETURN operations for the corresponding file		LAYOUTRETURN operations for the corresponding file
	with seqid less than the seqid given by CB_LAYOUTRECALL		with seqid less than the seqid given by CB_LAYOUTRECALL
	(lor_stateid; see <xref target="OP_CB_LAYOUTRECALL"/>.)		(lor_stateid; see <xref target="OP_CB_LAYOUTRECALL" format="default"/>.)
	</t>		</t>
	<t>		<t>
	In addition to the seqid-based mechanism,		In addition to the seqid-based mechanism,
	<xref target="sessions_callback_races"/>		<xref target="sessions_callback_races" format="default"/>
	describes the sessions mechanism for allowing the		describes the sessions mechanism for allowing the
	client to detect callback race conditions and delay processing such a		client to detect callback race conditions and delay processing such a
	CB_LAYOUTRECALL. The server MAY reference conflicting operations		CB_LAYOUTRECALL. The server <bcp14>MAY</bcp14> reference conflicting operation s
	in the CB_SEQUENCE that precedes the CB_LAYOUTRECALL.		in the CB_SEQUENCE that precedes the CB_LAYOUTRECALL.
	Because the server has already sent replies for these operations before		Because the server has already sent replies for these operations before
	sending the callback, the replies may race with the CB_LAYOUTRECALL.		sending the callback, the replies may race with the CB_LAYOUTRECALL.
	The client MUST wait for all the referenced calls to complete and update		The client <bcp14>MUST</bcp14> wait for all the referenced calls to complete a nd update
	its view of the layout state before processing the CB_LAYOUTRECALL.		its view of the layout state before processing the CB_LAYOUTRECALL.
	</t>		</t>
			<section numbered="true" toc="default">
	<section title="Get/Return Sequencing">		<name>Get/Return Sequencing</name>
	<t>		<t>
	The protocol allows the client to send concurrent		The protocol allows the client to send concurrent
	LAYOUTGET and LAYOUTRETURN operations to the server. The		LAYOUTGET and LAYOUTRETURN operations to the server. The
	protocol does not provide any means for the server to		protocol does not provide any means for the server to
	process the requests in the same order in which they		process the requests in the same order in which they
	were created. However, through the use of the "seqid"		were created. However, through the use of the "seqid"
	field in the layout stateid, the client can determine		field in the layout stateid, the client can determine
	the order in which parallel outstanding operations were		the order in which parallel outstanding operations were
	processed by the server. Thus, when a layout retrieved		processed by the server. Thus, when a layout retrieved
	by an outstanding LAYOUTGET operation intersects with		by an outstanding LAYOUTGET operation intersects with
	a layout returned by an outstanding LAYOUTRETURN on		a layout returned by an outstanding LAYOUTRETURN on
	the same file, the order in which the two conflicting		the same file, the order in which the two conflicting
	operations are processed determines the final state of		operations are processed determines the final state of
	the overlapping layout. The order is determined by		the overlapping layout. The order is determined by
	the "seqid" returned in each operation: the operation with the		the "seqid" returned in each operation: the operation with the
	higher seqid was executed later.		higher seqid was executed later.
	</t>		</t>
	<t>		<t>
	It is permissible for the client to send multiple parallel		It is permissible for the client to send multiple parallel
	LAYOUTGET operations for the same file or multiple parallel LAYOUTRETURN		LAYOUTGET operations for the same file or multiple parallel LAYOUTRETURN
	operations for the same file or a mix of both.		operations for the same file or a mix of both.
	</t>		</t>
	<t>		<t>
	It is permissible for the client to use the current stateid (see		It is permissible for the client to use the current stateid (see
	<xref target="current_stateid"/>) for LAYOUTGET operations, for		<xref target="current_stateid" format="default"/>) for LAYOUTGET operations, f or
	example, when compounding LAYOUTGETs or compounding OPEN and		example, when compounding LAYOUTGETs or compounding OPEN and
	LAYOUTGETs. It is also permissible to use the current stateid when		LAYOUTGETs. It is also permissible to use the current stateid when
	compounding LAYOUTRETURNs.		compounding LAYOUTRETURNs.
	</t>		</t>
	<t>		<t>
	It is permissible for the client to use the current stateid when		It is permissible for the client to use the current stateid when
	combining LAYOUTRETURN and LAYOUTGET operations for the same file in		combining LAYOUTRETURN and LAYOUTGET operations for the same file in
	the same COMPOUND request since the server MUST process these in		the same COMPOUND request since the server <bcp14>MUST</bcp14> process these i n
	order. However, if a client does send such COMPOUND requests, it		order. However, if a client does send such COMPOUND requests, it
	MUST NOT have more than one outstanding for the same file at the		<bcp14>MUST NOT</bcp14> have more than one outstanding for the same file at th
	same time, and it MUST NOT have other LAYOUTGET or LAYOUTRETURN		e
			same time, and it <bcp14>MUST NOT</bcp14> have other LAYOUTGET or LAYOUTRETURN
	operations outstanding at the same time for that same file.		operations outstanding at the same time for that same file.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="Client Considerations">		<name>Client Considerations</name>
	<t>		<t>
	Consider a pNFS client that has sent a LAYOUTGET, and before		Consider a pNFS client that has sent a LAYOUTGET, and before
	it receives the reply to LAYOUTGET, it receives		it receives the reply to LAYOUTGET, it receives
	a CB_LAYOUTRECALL for the same file with an overlapping range. There are two		a CB_LAYOUTRECALL for the same file with an overlapping range. There are two
	possibilities, which the client can distinguish		possibilities, which the client can distinguish
	via the layout stateid in the recall.		via the layout stateid in the recall.
	<list style="numbers">		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	The server processed the LAYOUTGET before sending the recall, so the		The server processed the LAYOUTGET before sending the recall, so the
	LAYOUTGET must be waited for because it		LAYOUTGET must be waited for because it
	may be carrying layout information that will need to be returned to deal		may be carrying layout information that will need to be returned to deal
	with the CB_LAYOUTRECALL.		with the CB_LAYOUTRECALL.
	</t>		</li>
	<t>		<li>
	The		The
	server sent the callback before receiving the		server sent the callback before receiving the
	LAYOUTGET. The server will not respond to the LAYOUTGET		LAYOUTGET. The server will not respond to the LAYOUTGET
	until the CB_LAYOUTRECALL is processed.		until the CB_LAYOUTRECALL is processed.
	</t>		</li>
	</list>		</ol>
			<t>
	If these possibilities cannot be distinguished, a		If these possibilities cannot be distinguished, a
	deadlock could result, as the client must wait for the		deadlock could result, as the client must wait for the
	LAYOUTGET response before processing the recall in the		LAYOUTGET response before processing the recall in the
	first case, but that response will not arrive until after		first case, but that response will not arrive until after
	the recall is processed in the second case. Note that		the recall is processed in the second case. Note that
	in the first case, the "seqid" in the layout stateid		in the first case, the "seqid" in the layout stateid
	of the recall is two greater than what the client has		of the recall is two greater than what the client has
	recorded; in the second case, the "seqid" is one greater than		recorded; in the second case, the "seqid" is one greater than
	what the client has recorded. This allows the client		what the client has recorded. This allows the client
	to disambiguate between the two cases. The client thus		to disambiguate between the two cases. The client thus
	knows precisely which possibility applies.		knows precisely which possibility applies.
	</t>		</t>
	<t>		<t>
	In case 1, the client knows it needs to wait for		In case 1, the client knows it needs to wait for
	the LAYOUTGET response before processing the recall		the LAYOUTGET response before processing the recall
	(or the client can return NFS4ERR_DELAY).		(or the client can return NFS4ERR_DELAY).
	</t>		</t>
	<t>		<t>
	In case 2, the client will not wait for the LAYOUTGET		In case 2, the client will not wait for the LAYOUTGET
	response before processing the recall because waiting		response before processing the recall because waiting
	would cause deadlock. Therefore, the action at the		would cause deadlock. Therefore, the action at the
	client will only require waiting in the case that the		client will only require waiting in the case that the
	client has not yet seen the server's earlier responses		client has not yet seen the server's earlier responses
	to the LAYOUTGET operation(s).		to the LAYOUTGET operation(s).
	</t>		</t>
	<t>		<t>
	The recall process can be considered completed when		The recall process can be considered completed when
	the final LAYOUTRETURN operation for the recalled range is completed.		the final LAYOUTRETURN operation for the recalled range is completed.
	The LAYOUTRETURN uses the layout stateid (with seqid) specified in		The LAYOUTRETURN uses the layout stateid (with seqid) specified in
	CB_LAYOUTRECALL. If the client uses multiple LAYOUTRETURNs in		CB_LAYOUTRECALL. If the client uses multiple LAYOUTRETURNs in
	processing the recall, the first LAYOUTRETURN will use the layout		processing the recall, the first LAYOUTRETURN will use the layout
	stateid as specified in CB_LAYOUTRECALL. Subsequent LAYOUTRETURNs		stateid as specified in CB_LAYOUTRECALL. Subsequent LAYOUTRETURNs
	will use the highest seqid as is the usual case.		will use the highest seqid as is the usual case.
	</t>		</t>
			</section>
	</section>		<section anchor="layout_server_consider" numbered="true" toc="defa
			ult">
	<section title="Server Considerations" anchor="layout_server_consider">		<name>Server Considerations</name>
	<t>		<t>
	Consider a race from the metadata server's point of		Consider a race from the metadata server's point of
	view. The metadata server has sent a CB_LAYOUTRECALL and receives		view. The metadata server has sent a CB_LAYOUTRECALL and receives
	an overlapping LAYOUTGET for the same file before the		an overlapping LAYOUTGET for the same file before the
	LAYOUTRETURN(s) that respond to the CB_LAYOUTRECALL. There are		LAYOUTRETURN(s) that respond to the CB_LAYOUTRECALL. There are
	three cases:		three cases:
	<list style="numbers">		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	The client sent the LAYOUTGET before processing the CB_LAYOUTRECALL.		The client sent the LAYOUTGET before processing the CB_LAYOUTRECALL.
	The "seqid" in the layout stateid of the arguments of LAYOUTGET is one less		The "seqid" in the layout stateid of the arguments of LAYOUTGET is one less
	than the "seqid" in CB_LAYOUTRECALL. The server returns		than the "seqid" in CB_LAYOUTRECALL. The server returns
	NFS4ERR_RECALLCONFLICT to the client, which indicates to the client		NFS4ERR_RECALLCONFLICT to the client, which indicates to the client
	that there is a pending recall.		that there is a pending recall.
	</t>		</li>
	<t>		<li>
	The client sent the LAYOUTGET after processing the		The client sent the LAYOUTGET after processing the
	CB_LAYOUTRECALL, but the LAYOUTGET arrived before the LAYOUTRETURN and		CB_LAYOUTRECALL, but the LAYOUTGET arrived before the LAYOUTRETURN and
	the response to CB_LAYOUTRECALL that		the response to CB_LAYOUTRECALL that
	completed that processing.		completed that processing.
	The "seqid" in the layout stateid		The "seqid" in the layout stateid
	of LAYOUTGET is equal to or greater than that of the "seqid" in		of LAYOUTGET is equal to or greater than that of the "seqid" in
	CB_LAYOUTRECALL.		CB_LAYOUTRECALL.
	The server has not received a response to the CB_LAYOUTRECALL,		The server has not received a response to the CB_LAYOUTRECALL,
	so it returns NFS4ERR_RECALLCONFLICT.		so it returns NFS4ERR_RECALLCONFLICT.
	</t>		</li>
	<t>		<li>
	The client sent the LAYOUTGET after processing the		The client sent the LAYOUTGET after processing the
	CB_LAYOUTRECALL; the server received the CB_LAYOUTRECALL		CB_LAYOUTRECALL; the server received the CB_LAYOUTRECALL
	response, but the LAYOUTGET arrived before the LAYOUTRETURN that		response, but the LAYOUTGET arrived before the LAYOUTRETURN that
	completed that processing.		completed that processing.
	The "seqid" in the layout stateid		The "seqid" in the layout stateid
	of LAYOUTGET is equal to that of the "seqid" in		of LAYOUTGET is equal to that of the "seqid" in
	CB_LAYOUTRECALL.		CB_LAYOUTRECALL.
	The server has received a response to the CB_LAYOUTRECALL,		The server has received a response to the CB_LAYOUTRECALL,
	so it returns NFS4ERR_RETURNCONFLICT.		so it returns NFS4ERR_RETURNCONFLICT.
	</t>		</li>
	</list>		</ol>
	</t>		</section>
			<section numbered="true" toc="default">
	</section>		<name>Wraparound and Validation of Seqid</name>
			<t>
	<section title="Wraparound and Validation of Seqid">
	<t>
	The rules for layout stateid processing differ from other stateids		The rules for layout stateid processing differ from other stateids
	in the protocol because the "seqid" value cannot be zero and the		in the protocol because the "seqid" value cannot be zero and the
	stateid's "seqid" value changes in a CB_LAYOUTRECALL operation. The		stateid's "seqid" value changes in a CB_LAYOUTRECALL operation. The
	non-zero requirement combined with the inherent parallelism of		non-zero requirement combined with the inherent parallelism of
	layout operations means that a set of LAYOUTGET and LAYOUTRETURN		layout operations means that a set of LAYOUTGET and LAYOUTRETURN
	operations may contain the same value for "seqid".		operations may contain the same value for "seqid".
	The server uses a slightly modified version of the modulo arithmetic		The server uses a slightly modified version of the modulo arithmetic
	as described in		as described in
	<xref target="Slot_Identifiers_and_Server_Reply_Cache" />		<xref target="Slot_Identifiers_and_Server_Reply_Cache" format="default"/>
	when incrementing the layout stateid's "seqid". The difference		when incrementing the layout stateid's "seqid". The difference
	is that zero is not a valid value for "seqid"; when the value		is that zero is not a valid value for "seqid"; when the value
	of a "seqid" is 0xFFFFFFFF, the next valid value will be 0x00000001.		of a "seqid" is 0xFFFFFFFF, the next valid value will be 0x00000001.
	The modulo arithmetic is also used for the comparisons of		The modulo arithmetic is also used for the comparisons of
	"seqid" values in the processing of CB_LAYOUTRECALL events as		"seqid" values in the processing of CB_LAYOUTRECALL events as
	described above in <xref target="layout_server_consider" />.		described above in <xref target="layout_server_consider" format="default"/>.
	</t>		</t>
	<t>		<t>
	Just as the server validates the "seqid" in the event of		Just as the server validates the "seqid" in the event of
	CB_LAYOUTRECALL usage, as described in		CB_LAYOUTRECALL usage, as described in
	<xref target="layout_server_consider" />, the server also validates		<xref target="layout_server_consider" format="default"/>, the server also vali dates
	the "seqid" value to ensure that it is within an appropriate range.		the "seqid" value to ensure that it is within an appropriate range.
	This range represents the degree of parallelism the server supports		This range represents the degree of parallelism the server supports
	for layout stateids. If the client is sending multiple layout		for layout stateids. If the client is sending multiple layout
	operations to the server in parallel, by definition, the "seqid"		operations to the server in parallel, by definition, the "seqid"
	value in the supplied stateid will not be the current "seqid" as		value in the supplied stateid will not be the current "seqid" as
	held by the server. The range of parallelism spans from the highest		held by the server. The range of parallelism spans from the highest
	or current "seqid" to a "seqid" value in the past. To assist in the		or current "seqid" to a "seqid" value in the past. To assist in the
	discussion, the server's current "seqid" value for a layout stateid		discussion, the server's current "seqid" value for a layout stateid
	is defined as SERVER_CURRENT_SEQID. The lowest "seqid" value that		is defined as SERVER_CURRENT_SEQID. The lowest "seqid" value that
	is acceptable to the server is represented by PAST_SEQID. And the		is acceptable to the server is represented by PAST_SEQID. And the
	value for the range of valid "seqid"s or range of parallelism is		value for the range of valid "seqid"s or range of parallelism is
	VALID_SEQID_RANGE. Therefore, the following holds:		VALID_SEQID_RANGE. Therefore, the following holds:
	VALID_SEQID_RANGE = SERVER_CURRENT_SEQID - PAST_SEQID. In the		VALID_SEQID_RANGE = SERVER_CURRENT_SEQID - PAST_SEQID. In the
	following, all arithmetic is the modulo arithmetic as described		following, all arithmetic is the modulo arithmetic as described
	above.		above.
	</t>		</t>
	<t>		<t>
	The server MUST support a minimum VALID_SEQID_RANGE. The minimum is		The server <bcp14>MUST</bcp14> support a minimum VALID_SEQID_RANGE. The minim
			um is
	defined as: VALID_SEQID_RANGE = summation over 1..N of		defined as: VALID_SEQID_RANGE = summation over 1..N of
	(ca_maxoperations(i) - 1), where N is the number of session fore		(ca_maxoperations(i) - 1), where N is the number of session fore
	channels and ca_maxoperations(i) is the value of the ca_maxoperations returned from		channels and ca_maxoperations(i) is the value of the ca_maxoperations returned from
	CREATE_SESSION of the i'th session. The reason for "- 1" is to allow for the required		CREATE_SESSION of the i'th session. The reason for "- 1" is to allow for the required
	SEQUENCE operation. The server MAY support a VALID_SEQID_RANGE		SEQUENCE operation. The server <bcp14>MAY</bcp14> support a VALID_SEQID_RANGE
	value larger than the minimum. The maximum VALID_SEQID_RANGE is (2		value larger than the minimum. The maximum VALID_SEQID_RANGE is (2<sup>32</su
	^ 32 - 2) (accounting for zero not being a valid "seqid" value).		p> - 2) (accounting for zero not being a valid "seqid" value).
	</t>		</t>
	<t>		<t>
	If the server finds the "seqid" is zero, the NFS4ERR_BAD_STATEID		If the server finds the "seqid" is zero, the NFS4ERR_BAD_STATEID
	error is returned to the client. The server further validates the		error is returned to the client. The server further validates the
	"seqid" to ensure it is within the range of parallelism,		"seqid" to ensure it is within the range of parallelism,
	VALID_SEQID_RANGE. If the "seqid" value is outside of that range,		VALID_SEQID_RANGE. If the "seqid" value is outside of that range,
	the error NFS4ERR_OLD_STATEID is returned to the client. Upon		the error NFS4ERR_OLD_STATEID is returned to the client. Upon
	receipt of NFS4ERR_OLD_STATEID, the client updates the stateid in		receipt of NFS4ERR_OLD_STATEID, the client updates the stateid in
	the layout request based on processing of other layout requests and		the layout request based on processing of other layout requests and
	re-sends the operation to the server.		re-sends the operation to the server.
	</t>		</t>
	</section>		</section>
			<section anchor="bulk_layouts" numbered="true" toc="default">
	<section title="Bulk Recall and Return" anchor="bulk_layouts">		<name>Bulk Recall and Return</name>
			<t>
	<t>
	pNFS supports recalling and returning all layouts that		pNFS supports recalling and returning all layouts that
	are for files belonging to a particular fsid		are for files belonging to a particular fsid
	(LAYOUTRECALL4_FSID, LAYOUTRETURN4_FSID) or client ID		(LAYOUTRECALL4_FSID, LAYOUTRETURN4_FSID) or client ID
	(LAYOUTRECALL4_ALL, LAYOUTRETURN4_ALL).		(LAYOUTRECALL4_ALL, LAYOUTRETURN4_ALL).
	There are no "bulk" stateids, so detection of races		There are no "bulk" stateids, so detection of races
	via the seqid is not possible.		via the seqid is not possible.
	The server MUST NOT initiate bulk recall while another		The server <bcp14>MUST NOT</bcp14> initiate bulk recall while another
	recall is in progress, or the corresponding LAYOUTRETURN		recall is in progress, or the corresponding LAYOUTRETURN
	is in progress or pending.		is in progress or pending.
	In the event the server sends a bulk recall		In the event the server sends a bulk recall
	while the client has a pending or in-progress LAYOUTRETURN,		while the client has a pending or in-progress LAYOUTRETURN,
	CB_LAYOUTRECALL, or LAYOUTGET, the client returns		CB_LAYOUTRECALL, or LAYOUTGET, the client returns
	NFS4ERR_DELAY. In the event the client sends a LAYOUTGET		NFS4ERR_DELAY. In the event the client sends a LAYOUTGET
	or LAYOUTRETURN while a bulk recall is in progress, the		or LAYOUTRETURN while a bulk recall is in progress, the
	server returns NFS4ERR_RECALLCONFLICT.		server returns NFS4ERR_RECALLCONFLICT.
	If the client sends a LAYOUTGET or LAYOUTRETURN after		If the client sends a LAYOUTGET or LAYOUTRETURN after
	the server receives NFS4ERR_DELAY from a bulk recall,		the server receives NFS4ERR_DELAY from a bulk recall,
	then to ensure forward progress, the server MAY return		then to ensure forward progress, the server <bcp14>MAY</bcp14> return
	NFS4ERR_RECALLCONFLICT.		NFS4ERR_RECALLCONFLICT.
	</t>		</t>
	<t>		<t>
	Once a CB_LAYOUTRECALL of LAYOUTRECALL4_ALL is sent,		Once a CB_LAYOUTRECALL of LAYOUTRECALL4_ALL is sent,
	the server MUST NOT allow the client to use any layout		the server <bcp14>MUST NOT</bcp14> allow the client to use any layout
	stateid except for LAYOUTCOMMIT operations. Once the client receives		stateid except for LAYOUTCOMMIT operations. Once the client receives
	a CB_LAYOUTRECALL of LAYOUTRECALL4_ALL, it MUST NOT use		a CB_LAYOUTRECALL of LAYOUTRECALL4_ALL, it <bcp14>MUST NOT</bcp14> use
	any layout stateid except for LAYOUTCOMMIT operations.		any layout stateid except for LAYOUTCOMMIT operations.
	Once a LAYOUTRETURN of LAYOUTRETURN4_ALL is sent, all		Once a LAYOUTRETURN of LAYOUTRETURN4_ALL is sent, all
	layout stateids granted to the client ID are freed.		layout stateids granted to the client ID are freed.
	The client MUST NOT use the layout stateids again. It		The client <bcp14>MUST NOT</bcp14> use the layout stateids again. It
	MUST use LAYOUTGET to obtain new layout stateids.		<bcp14>MUST</bcp14> use LAYOUTGET to obtain new layout stateids.
	</t>		</t>
	<t>		<t>
	Once a CB_LAYOUTRECALL of LAYOUTRECALL4_FSID is sent, the		Once a CB_LAYOUTRECALL of LAYOUTRECALL4_FSID is sent, the
	server MUST NOT allow the client to use any layout stateid		server <bcp14>MUST NOT</bcp14> allow the client to use any layout stateid
	that refers to a file with the specified fsid except for		that refers to a file with the specified fsid except for
	LAYOUTCOMMIT operations. Once the client receives a CB_LAYOUTRECALL		LAYOUTCOMMIT operations. Once the client receives a CB_LAYOUTRECALL
	of LAYOUTRECALL4_ALL, it MUST NOT use any layout stateid		of LAYOUTRECALL4_ALL, it <bcp14>MUST NOT</bcp14> use any layout stateid
	that refers to a file with the specified fsid except		that refers to a file with the specified fsid except
	for LAYOUTCOMMIT operations.		for LAYOUTCOMMIT operations.
	Once a LAYOUTRETURN of LAYOUTRETURN4_FSID is sent, all		Once a LAYOUTRETURN of LAYOUTRETURN4_FSID is sent, all
	layout stateids granted to the referenced fsid are freed.		layout stateids granted to the referenced fsid are freed.
	The client MUST NOT use those freed layout stateids for files		The client <bcp14>MUST NOT</bcp14> use those freed layout stateids for files
	with the referenced fsid again. Subsequently, for any file with		with the referenced fsid again. Subsequently, for any file with
	the referenced fsid, to use a layout, the client MUST first		the referenced fsid, to use a layout, the client <bcp14>MUST</bcp14> first
	send a LAYOUTGET operation in order to		send a LAYOUTGET operation in order to
	obtain a new layout stateid for that file.		obtain a new layout stateid for that file.
	</t>		</t>
	<t>		<t>
	If the server has sent a bulk CB_LAYOUTRECALL and		If the server has sent a bulk CB_LAYOUTRECALL and
	receives a LAYOUTGET, or a LAYOUTRETURN with a stateid,		receives a LAYOUTGET, or a LAYOUTRETURN with a stateid,
	the server MUST return NFS4ERR_RECALLCONFLICT. If the		the server <bcp14>MUST</bcp14> return NFS4ERR_RECALLCONFLICT. If the
	server has sent a bulk CB_LAYOUTRECALL and receives a		server has sent a bulk CB_LAYOUTRECALL and receives a
	LAYOUTRETURN with an lr_returntype that is not equal to		LAYOUTRETURN with an lr_returntype that is not equal to
	the lor_recalltype of the CB_LAYOUTRECALL, the server		the lor_recalltype of the CB_LAYOUTRECALL, the server
	MUST return NFS4ERR_RECALLCONFLICT.		<bcp14>MUST</bcp14> return NFS4ERR_RECALLCONFLICT.
	</t>		</t>
	</section>		</section>
			</section>
	</section>		</section>
	</section>		</section>
	</section>		<section anchor="revoke_layout" numbered="true" toc="default">
			<name>Revoking Layouts</name>
	<section title="Revoking Layouts" anchor="revoke_layout">		<t>
	<t>
	Parallel NFS permits servers to revoke layouts from clients		Parallel NFS permits servers to revoke layouts from clients
	that fail to respond to recalls and/or fail to renew their		that fail to respond to recalls and/or fail to renew their
	lease in time. Depending on the layout type,		lease in time. Depending on the layout type,
	the server might revoke the layout and might take certain actions		the server might revoke the layout and might take certain actions
	with respect to the client's I/O to data servers.		with respect to the client's I/O to data servers.
	</t>		</t>
	</section>		</section>
	<section title="Metadata Server Write Propagation" anchor="async_writes">		<section anchor="async_writes" numbered="true" toc="default">
	<t>		<name>Metadata Server Write Propagation</name>
			<t>
	Asynchronous writes written through the metadata server may be		Asynchronous writes written through the metadata server may be
	propagated lazily to the storage devices. For data written		propagated lazily to the storage devices. For data written
	asynchronously through the metadata server, a client performing a		asynchronously through the metadata server, a client performing a
	read at the appropriate storage device is not guaranteed to see the		read at the appropriate storage device is not guaranteed to see the
	newly written data until a COMMIT occurs at the metadata server.		newly written data until a COMMIT occurs at the metadata server.
	While the write is pending, reads to the storage device may give out		While the write is pending, reads to the storage device may give out
	either the old data, the new data, or a mixture of new and old.		either the old data, the new data, or a mixture of new and old.
	Upon completion of a synchronous WRITE or COMMIT (for asynchronously		Upon completion of a synchronous WRITE or COMMIT (for asynchronously
	written data), the metadata server MUST ensure that storage devices		written data), the metadata server <bcp14>MUST</bcp14> ensure that storage dev ices
	give out the new data and that the data has been written to stable		give out the new data and that the data has been written to stable
	storage. If the server implements its storage in any way such that		storage. If the server implements its storage in any way such that
	it cannot obey these constraints, then it MUST recall the layouts to		it cannot obey these constraints, then it <bcp14>MUST</bcp14> recall the layou ts to
	prevent reads being done that cannot be handled correctly. Note		prevent reads being done that cannot be handled correctly. Note
	that the layouts MUST be recalled prior to the server responding to		that the layouts <bcp14>MUST</bcp14> be recalled prior to the server respondin g to
	the associated WRITE operations.		the associated WRITE operations.
	</t>		</t>
	</section>		</section>
			</section>
	</section>		<section numbered="true" toc="default">
			<name>pNFS Mechanics</name>
	<section title="pNFS Mechanics">		<t>
	<t>
	This section describes the operations flow taken by a pNFS client		This section describes the operations flow taken by a pNFS client
	to a metadata server and storage device.		to a metadata server and storage device.
	</t>		</t>
	<t>		<t>
	When a pNFS client encounters a new FSID, it sends a GETATTR to the		When a pNFS client encounters a new FSID, it sends a GETATTR to the
	NFSv4.1 server for the fs_layout_type (<xref target="attrdef_fs_layout_type"		NFSv4.1 server for the fs_layout_type (<xref target="attrdef_fs_layout_type" f
	/>) attribute. If the attribute returns at least one layout type,		ormat="default"/>) attribute. If the attribute returns at least one layout type,
	and the layout types returned are among the set supported by		and the layout types returned are among the set supported by
	the client, the client knows that pNFS is a possibility for the file		the client, the client knows that pNFS is a possibility for the file
	system. If, from the server that returned the new FSID, the client		system. If, from the server that returned the new FSID, the client
	does not have a client ID that came from an EXCHANGE_ID result that		does not have a client ID that came from an EXCHANGE_ID result that
	returned EXCHGID4_FLAG_USE_PNFS_MDS, it MUST send an EXCHANGE_ID to		returned EXCHGID4_FLAG_USE_PNFS_MDS, it <bcp14>MUST</bcp14> send an EXCHANGE_I D to
	the server with the EXCHGID4_FLAG_USE_PNFS_MDS bit set. If the		the server with the EXCHGID4_FLAG_USE_PNFS_MDS bit set. If the
	server's response does not have EXCHGID4_FLAG_USE_PNFS_MDS, then		server's response does not have EXCHGID4_FLAG_USE_PNFS_MDS, then
	contrary to what the fs_layout_type attribute said, the server does		contrary to what the fs_layout_type attribute said, the server does
	not support pNFS, and the client will not be able use pNFS to that		not support pNFS, and the client will not be able use pNFS to that
	server; in this case, the server MUST return NFS4ERR_NOTSUPP in		server; in this case, the server <bcp14>MUST</bcp14> return NFS4ERR_NOTSUPP in
	response to any pNFS operation.		response to any pNFS operation.
	</t>		</t>
	<t>		<t>
	The client then creates a session, requesting a persistent session, so		The client then creates a session, requesting a persistent session, so
	that exclusive creates can be done with single round trip via the		that exclusive creates can be done with single round trip via the
	createmode4 of GUARDED4. If the session ends up not being persistent,		createmode4 of GUARDED4. If the session ends up not being persistent,
	the client will use EXCLUSIVE4_1 for exclusive creates.		the client will use EXCLUSIVE4_1 for exclusive creates.
	</t>		</t>
	<t>		<t>
	If a file is to be created on a pNFS-enabled file		If a file is to be created on a pNFS-enabled file
	system, the client uses the OPEN operation. With the		system, the client uses the OPEN operation. With the
	normal set of attributes that may be provided upon OPEN		normal set of attributes that may be provided upon OPEN
	used for creation, there is an OPTIONAL layout_hint		used for creation, there is an <bcp14>OPTIONAL</bcp14> layout_hint
	attribute. The client's use of layout_hint allows the		attribute. The client's use of layout_hint allows the
	client to express its preference for a layout type and its		client to express its preference for a layout type and its
	associated layout details. The use of a createmode4 of		associated layout details. The use of a createmode4 of
	UNCHECKED4, GUARDED4, or EXCLUSIVE4_1 will allow the		UNCHECKED4, GUARDED4, or EXCLUSIVE4_1 will allow the
	client to provide the layout_hint attribute at create		client to provide the layout_hint attribute at create
	time. The client MUST NOT use EXCLUSIVE4 (see <xref		time. The client <bcp14>MUST NOT</bcp14> use EXCLUSIVE4 (see <xref target="exc
	target="exclusive_create"/>). The client is RECOMMENDED		lusive_create" format="default"/>). The client is <bcp14>RECOMMENDED</bcp14>
	to combine a GETATTR operation after the OPEN within		to combine a GETATTR operation after the OPEN within
	the same COMPOUND. The GETATTR may then retrieve		the same COMPOUND. The GETATTR may then retrieve
	the layout_type attribute for the newly created file.		the layout_type attribute for the newly created file.
	The client will then know what layout type the server has		The client will then know what layout type the server has
	chosen for the file and therefore what storage protocol		chosen for the file and therefore what storage protocol
	the client must use.		the client must use.
	</t>		</t>
	<t>		<t>
	If the client wants to open an existing file, then it also includes		If the client wants to open an existing file, then it also includes
	a GETATTR to determine what layout type the file supports.		a GETATTR to determine what layout type the file supports.
	</t>		</t>
	<t>		<t>
	The GETATTR in either the file creation or plain file open case can		The GETATTR in either the file creation or plain file open case can
	also include the layout_blksize and layout_alignment attributes so		also include the layout_blksize and layout_alignment attributes so
	that the client can determine optimal offsets and lengths for I/O on		that the client can determine optimal offsets and lengths for I/O on
	the file.		the file.
	</t>		</t>
	<t>		<t>
	Assuming the client supports the layout type returned by GETATTR and		Assuming the client supports the layout type returned by GETATTR and
	it chooses to use pNFS for data access, it then sends LAYOUTGET		it chooses to use pNFS for data access, it then sends LAYOUTGET
	using the filehandle and stateid returned by OPEN, specifying the range it wan ts		using the filehandle and stateid returned by OPEN, specifying the range it wan ts
	to do I/O on. The response is a layout, which may be a subset of the		to do I/O on. The response is a layout, which may be a subset of the
	range for which the client asked. It also includes device IDs and a		range for which the client asked. It also includes device IDs and a
	description of how data is organized (or in the case of writing, how		description of how data is organized (or in the case of writing, how
	data is to be organized) across the devices. The device IDs and		data is to be organized) across the devices. The device IDs and
	data description are encoded in a format that is specific to the		data description are encoded in a format that is specific to the
	layout type, but the client is expected to understand.		layout type, but the client is expected to understand.
	</t>		</t>
	<t>		<t>
	When the client wants to send an I/O, it determines to which device ID		When the client wants to send an I/O, it determines to which device ID
	it needs to send the I/O command by examining the data		it needs to send the I/O command by examining the data
	description in the layout. It then sends a		description in the layout. It then sends a
	GETDEVICEINFO to find the device address(es) of the device ID. The		GETDEVICEINFO to find the device address(es) of the device ID. The
	client then sends the I/O request to one of device ID's device addresses, usin g the		client then sends the I/O request to one of device ID's device addresses, usin g the
	storage protocol defined for the layout type.		storage protocol defined for the layout type.
	Note that if a client has multiple I/Os to send,		Note that if a client has multiple I/Os to send,
	these I/O requests may be done in parallel.		these I/O requests may be done in parallel.
	</t>		</t>
	<t>		<t>
	If the I/O was a WRITE, then at some point		If the I/O was a WRITE, then at some point
	the client may want to use LAYOUTCOMMIT to		the client may want to use LAYOUTCOMMIT to
	commit the modification time and the new size		commit the modification time and the new size
	of the file (if it believes it extended the file size) to the		of the file (if it believes it extended the file size) to the
	metadata server and the modified data to the file system.		metadata server and the modified data to the file system.
	</t>		</t>
	</section>		</section>
	<section title="Recovery" anchor="crash_recovery">		<section anchor="crash_recovery" numbered="true" toc="default">
	<t>		<name>Recovery</name>
			<t>
	Recovery is complicated by the distributed nature of the pNFS		Recovery is complicated by the distributed nature of the pNFS
	protocol. In general, crash recovery for layouts is similar to		protocol. In general, crash recovery for layouts is similar to
	crash recovery for delegations in the base NFSv4.1 protocol. However,		crash recovery for delegations in the base NFSv4.1 protocol. However,
	the client's ability to perform I/O without contacting the metadata		the client's ability to perform I/O without contacting the metadata
	server introduces subtleties that must be handled correctly if		server introduces subtleties that must be handled correctly if
	the possibility of file system corruption is to be avoided.		the possibility of file system corruption is to be avoided.
	</t>		</t>
	<section title="Recovery from Client Restart" anchor="pnfs_client_recovery">		<section anchor="pnfs_client_recovery" numbered="true" toc="default">
	<t>		<name>Recovery from Client Restart</name>
			<t>
	Client recovery for layouts is similar to client recovery for other		Client recovery for layouts is similar to client recovery for other
	lock and delegation state. When a pNFS client restarts, it will lose		lock and delegation state. When a pNFS client restarts, it will lose
	all information about the layouts that it previously owned. There		all information about the layouts that it previously owned. There
	are two methods by which the server can reclaim these resources and		are two methods by which the server can reclaim these resources and
	allow otherwise conflicting layouts to be provided to other		allow otherwise conflicting layouts to be provided to other
	clients.		clients.
	</t>		</t>
	<t>		<t>
	The first is through the expiry of the client's lease. If the		The first is through the expiry of the client's lease. If the
	client recovery time is longer than the lease period, the client's		client recovery time is longer than the lease period, the client's
	lease will expire and the server will know that state may be		lease will expire and the server will know that state may be
	released. For layouts, the server may release the state immediately		released. For layouts, the server may release the state immediately
	upon lease expiry or it may allow the layout to persist, awaiting		upon lease expiry or it may allow the layout to persist, awaiting
	possible lease revival, as long as no other layout conflicts.		possible lease revival, as long as no other layout conflicts.
	</t>		</t>
	<t>		<t>
	The second is through the client restarting in less time than it		The second is through the client restarting in less time than it
	takes for the lease period to expire. In such a case, the client		takes for the lease period to expire. In such a case, the client
	will contact the server through the standard EXCHANGE_ID protocol.		will contact the server through the standard EXCHANGE_ID protocol.
	The server will find that the client's co_ownerid matches the		The server will find that the client's co_ownerid matches the
	co_ownerid of the previous client invocation, but that the verifier		co_ownerid of the previous client invocation, but that the verifier
	is different. The server uses this as a signal to release all		is different. The server uses this as a signal to release all
	layout state associated with the client's previous invocation. In		layout state associated with the client's previous invocation. In
	this scenario, the data written by the client but not covered by a		this scenario, the data written by the client but not covered by a
	successful LAYOUTCOMMIT is in an undefined state; it may have been		successful LAYOUTCOMMIT is in an undefined state; it may have been
	written or it may now be lost. This is acceptable behavior and it		written or it may now be lost. This is acceptable behavior and it
	is the client's responsibility to use LAYOUTCOMMIT to achieve the		is the client's responsibility to use LAYOUTCOMMIT to achieve the
	desired level of stability.		desired level of stability.
	</t>		</t>
	</section>		</section>
			<section anchor="lease_expiration_client" numbered="true" toc="default">
	<section title="Dealing with Lease Expiration on the Client"		<name>Dealing with Lease Expiration on the Client</name>
	anchor="lease_expiration_client">		<t anchor="pnfs_clnt_case1">
	<t anchor="pnfs_clnt_case1">		If a client believes its lease has expired, it <bcp14>MUST NOT</bcp14> send I
	If a client believes its lease has expired, it MUST NOT send I/O		/O
	to the storage device until it has validated its lease. The client		to the storage device until it has validated its lease. The client
	can send a SEQUENCE operation to the metadata server. If the		can send a SEQUENCE operation to the metadata server. If the
	SEQUENCE operation is successful, but sr_status_flag has		SEQUENCE operation is successful, but sr_status_flag has
	SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED,		SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED,
	SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED, or		SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED, or
	SEQ4_STATUS_ADMIN_STATE_REVOKED set, the client MUST NOT use		SEQ4_STATUS_ADMIN_STATE_REVOKED set, the client <bcp14>MUST NOT</bcp14> use
	currently held layouts. The client has two		currently held layouts. The client has two
	choices to recover from the lease expiration. First, for all		choices to recover from the lease expiration. First, for all
	modified but uncommitted data, the client writes it to the metadata server		modified but uncommitted data, the client writes it to the metadata server
	using the FILE_SYNC4 flag for the WRITEs, or WRITE and		using the FILE_SYNC4 flag for the WRITEs, or WRITE and
	COMMIT. Second, the client re-establishes a client ID and session with		COMMIT. Second, the client re-establishes a client ID and session with
	the server and obtains new layouts and device-ID-to-device-address		the server and obtains new layouts and device-ID-to-device-address
	mappings for the modified data ranges and then writes the data to the		mappings for the modified data ranges and then writes the data to the
	storage devices with the newly obtained layouts.		storage devices with the newly obtained layouts.
	</t>		</t>
	<t anchor="pnfs_clnt_case2">		<t anchor="pnfs_clnt_case2">
	If sr_status_flags from the metadata server has		If sr_status_flags from the metadata server has
	SEQ4_STATUS_RESTART_RECLAIM_NEEDED set		SEQ4_STATUS_RESTART_RECLAIM_NEEDED set
	(or SEQUENCE returns NFS4ERR_BAD_SESSION and		(or SEQUENCE returns NFS4ERR_BAD_SESSION and
	CREATE_SESSION returns NFS4ERR_STALE_CLIENTID), then the metadata		CREATE_SESSION returns NFS4ERR_STALE_CLIENTID), then the metadata
	server has restarted, and the client SHOULD recover using the		server has restarted, and the client <bcp14>SHOULD</bcp14> recover using the
	methods described in <xref target="mds_recovery" />.		methods described in <xref target="mds_recovery" format="default"/>.
	</t>		</t>
	<t anchor="pnfs_clnt_case3">		<t anchor="pnfs_clnt_case3">
	If sr_status_flags from the metadata server has		If sr_status_flags from the metadata server has
	SEQ4_STATUS_LEASE_MOVED set, then the client recovers by following		SEQ4_STATUS_LEASE_MOVED set, then the client recovers by following
	the procedure described in <xref		the procedure described in <xref target="transferred_lease" format="default"/
	target="transferred_lease"/>. After that, the client may get an		>. After that, the client may get an
	indication that the layout state was not moved with the file		indication that the layout state was not moved with the file
	system. The client recovers as in the other		system. The client recovers as in the other
	applicable situations discussed in the first two paragraphs of this section.		applicable situations discussed in the first two paragraphs of this section.
	</t>		</t>
	<t anchor="pnfs_clnt_case4">		<t anchor="pnfs_clnt_case4">
	If sr_status_flags reports no loss of state, then the lease for the		If sr_status_flags reports no loss of state, then the lease for the
	layouts that the client has are valid and		layouts that the client has are valid and
	renewed, and the client can once again send I/O requests to the		renewed, and the client can once again send I/O requests to the
	storage devices.		storage devices.
	</t>		</t>
	<t>		<t>
	While clients SHOULD NOT send I/Os to storage devices that may		While clients <bcp14>SHOULD NOT</bcp14> send I/Os to storage devices that may
	extend past the lease expiration time period, this is not always		extend past the lease expiration time period, this is not always
	possible, for example, an extended network partition that starts		possible, for example, an extended network partition that starts
	after the I/O is sent and does not heal until the I/O request is		after the I/O is sent and does not heal until the I/O request is
	received by the storage device. Thus, the metadata server and/or		received by the storage device. Thus, the metadata server and/or
	storage devices are responsible for protecting themselves from I/Os		storage devices are responsible for protecting themselves from I/Os
	that are both sent before the lease expires and arrive after the lease		that are both sent before the lease expires and arrive after the lease
	expires. See <xref target="lease_expiration_mds" />.		expires. See <xref target="lease_expiration_mds" format="default"/>.
	</t>		</t>
	</section>		</section>
			<section anchor="lease_expiration_mds" numbered="true" toc="default">
	<section title="Dealing with Loss of Layout State on the Metadata Server"		<name>Dealing with Loss of Layout State on the Metadata Server</name>
	anchor="lease_expiration_mds">		<t>
	<t>
	This is a description of the case where all of the following are		This is a description of the case where all of the following are
	true:		true:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	the metadata server has not restarted		the metadata server has not restarted
	</t>		</li>
	<t>		<li>
	a pNFS client's		a pNFS client's
	layouts have been discarded (usually because the client's lease		layouts have been discarded (usually because the client's lease
	expired) and are invalid		expired) and are invalid
	</t>		</li>
	<t>		<li>
	an I/O from the pNFS client arrives at the storage device		an I/O from the pNFS client arrives at the storage device
	</t>		</li>
	</list>		</ul>
	The metadata server and its storage devices MUST solve this by		<t>
	fencing the client. In other words, they MUST solve this by		The metadata server and its storage devices <bcp14>MUST</bcp14> solve this by
			fencing the client. In other words, they <bcp14>MUST</bcp14> solve this by
	preventing the execution of I/O operations from the client to the		preventing the execution of I/O operations from the client to the
	storage devices after layout		storage devices after layout
	state loss. The details of how fencing is done are specific to the		state loss. The details of how fencing is done are specific to the
	layout type. The solution for NFSv4.1 file-based layouts is		layout type. The solution for NFSv4.1 file-based layouts is
	described in (<xref target="file_layout_revoke" />), and solutions for other		described in (<xref target="file_layout_revoke" format="default"/>), and solu tions for other
	layout types are in their respective external specification documents.		layout types are in their respective external specification documents.
	</t>		</t>
	</section>		</section>
			<section anchor="mds_recovery" numbered="true" toc="default">
	<section title="Recovery from Metadata Server Restart" anchor="mds_recovery">		<name>Recovery from Metadata Server Restart</name>
	<t>		<t>
	The pNFS client will discover that the metadata server has		The pNFS client will discover that the metadata server has
	restarted via the methods described in <xref		restarted via the methods described in <xref target="server_failure" format=
	target="server_failure" /> and discussed in a pNFS-specific		"default"/> and discussed in a pNFS-specific
	context in <xref target="pnfs_clnt_case2" />. The client MUST stop using		context in <xref target="pnfs_clnt_case2" format="default"/>. The client <b
			cp14>MUST</bcp14> stop using
	layouts and delete the device ID to device address mappings it		layouts and delete the device ID to device address mappings it
	previously received from the metadata server. Having done that,		previously received from the metadata server. Having done that,
	if the client wrote data to the storage device without committing		if the client wrote data to the storage device without committing
	the layouts via LAYOUTCOMMIT, then the client has		the layouts via LAYOUTCOMMIT, then the client has
	additional work to do in order to have the client, metadata server,		additional work to do in order to have the client, metadata server,
	and storage device(s) all synchronized on the state of the data.		and storage device(s) all synchronized on the state of the data.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	If the client has data still modified		If the client has data still modified
	and unwritten in the client's memory, the client has only two choices.		and unwritten in the client's memory, the client has only two choices.
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	The client can obtain a layout via LAYOUTGET after the		The client can obtain a layout via LAYOUTGET after the
	server's grace period and write the data to the storage devices.		server's grace period and write the data to the storage devices.
	</t>		</li>
	<t>		<li>
	The client can WRITE that data through the metadata server using the		The client can WRITE that data through the metadata server using the
	WRITE (<xref target="OP_WRITE" />) operation, and then obtain		WRITE (<xref target="OP_WRITE" format="default"/>) operation, and then obta in
	layouts as desired.		layouts as desired.
	</t>		</li>
	</list>		</ol>
	</t>		</li>
	<t>		<li>
	If the client asynchronously wrote data to the storage device, but		If the client asynchronously wrote data to the storage device, but
	still has a copy of the data in its memory, then it has available		still has a copy of the data in its memory, then it has available
	to it the recovery options listed above in the previous bullet		to it the recovery options listed above in the previous bullet
	point. If the metadata server is also in its grace period, the		point. If the metadata server is also in its grace period, the
	client has available to it the options below in the next bullet		client has available to it the options below in the next bullet
	point.		point.
	</t>		</li>
	<t>		<li>
			<t>
	The client does not have a copy of the data in its memory and the		The client does not have a copy of the data in its memory and the
	metadata server is still in its grace period. The client cannot		metadata server is still in its grace period. The client cannot
	use LAYOUTGET (within or outside the grace period) to reclaim a		use LAYOUTGET (within or outside the grace period) to reclaim a
	layout because the contents of the response from LAYOUTGET		layout because the contents of the response from LAYOUTGET
	may not match what it had previously. The range might be		may not match what it had previously. The range might be
	different or the client might get the same range but the content of the		different or the client might get the same range but the content of the
	layout might be different. Even if the content of the layout		layout might be different. Even if the content of the layout
	appears to be the same, the device IDs may map to different		appears to be the same, the device IDs may map to different
	device addresses, and even if the device addresses are the same,		device addresses, and even if the device addresses are the same,
	the device addresses could have been assigned to a different		the device addresses could have been assigned to a different
	storage device. The option of retrieving the data from the		storage device. The option of retrieving the data from the
	storage device and writing it to the metadata server per the		storage device and writing it to the metadata server per the
	recovery scenario described above is		recovery scenario described above is
	not available because, again, the mappings of range to device ID,		not available because, again, the mappings of range to device ID,
	device ID to device address, and device address to physical device are		device ID to device address, and device address to physical device are
	stale, and new mappings via new LAYOUTGET do not solve the problem.		stale, and new mappings via new LAYOUTGET do not solve the problem.
	<vspace blankLines='1' />		</t>
			<t>
	The only recovery option for this scenario is to send a		The only recovery option for this scenario is to send a
	LAYOUTCOMMIT in reclaim mode, which the metadata server will		LAYOUTCOMMIT in reclaim mode, which the metadata server will
	accept as long as it is in its grace period. The use of		accept as long as it is in its grace period. The use of
	LAYOUTCOMMIT in reclaim mode informs the metadata server that the		LAYOUTCOMMIT in reclaim mode informs the metadata server that the
	layout has changed. It is critical that the metadata server		layout has changed. It is critical that the metadata server
	receive this information before its grace period ends, and thus		receive this information before its grace period ends, and thus
	before it starts allowing updates to the file system.		before it starts allowing updates to the file system.
	<vspace blankLines='1' />		</t>
			<t>
	To send LAYOUTCOMMIT in reclaim mode, the client sets the		To send LAYOUTCOMMIT in reclaim mode, the client sets the
	loca_reclaim field of the operation's arguments (<xref		loca_reclaim field of the operation's arguments (<xref target="OP_LAYOUTCOMM
	target="OP_LAYOUTCOMMIT_ARGUMENT"/>) to TRUE. During the metadata		IT_ARGUMENT" format="default"/>) to TRUE. During the metadata
	server's recovery grace period (and only during the recovery grace		server's recovery grace period (and only during the recovery grace
	period) the metadata server is prepared to accept LAYOUTCOMMIT		period) the metadata server is prepared to accept LAYOUTCOMMIT
	requests with the loca_reclaim field set to TRUE.		requests with the loca_reclaim field set to TRUE.
	<vspace blankLines='1' />		</t>
			<t>
	When loca_reclaim is TRUE, the client is attempting to commit		When loca_reclaim is TRUE, the client is attempting to commit
	changes to the layout that occurred prior to the restart		changes to the layout that occurred prior to the restart
	of the metadata server. The metadata server applies some		of the metadata server. The metadata server applies some
	consistency checks on the loca_layoutupdate field of the arguments		consistency checks on the loca_layoutupdate field of the arguments
	to determine whether the client can commit the data written to the		to determine whether the client can commit the data written to the
	storage device to the file system. The loca_layoutupdate field is of		storage device to the file system. The loca_layoutupdate field is of
	data type layoutupdate4 and contains layout-type-specific content		data type layoutupdate4 and contains layout-type-specific content
	(in the lou_body field of loca_layoutupdate). The		(in the lou_body field of loca_layoutupdate). The
	layout-type-specific information that loca_layoutupdate might have		layout-type-specific information that loca_layoutupdate might have
	is discussed in <xref target="layoutcommit_update" />. If the		is discussed in <xref target="layoutcommit_update" format="default"/>. If t he
	metadata server's consistency checks on loca_layoutupdate succeed,		metadata server's consistency checks on loca_layoutupdate succeed,
	then the metadata server MUST commit the data (as described by the		then the metadata server <bcp14>MUST</bcp14> commit the data (as described b y the
	loca_offset, loca_length, and loca_layoutupdate fields of the		loca_offset, loca_length, and loca_layoutupdate fields of the
	arguments) that was written to the storage device. If the metadata		arguments) that was written to the storage device. If the metadata
	server's consistency checks on loca_layoutupdate fail, the		server's consistency checks on loca_layoutupdate fail, the
	metadata server rejects the LAYOUTCOMMIT operation and makes no		metadata server rejects the LAYOUTCOMMIT operation and makes no
	changes to the file system. However, any time LAYOUTCOMMIT with		changes to the file system. However, any time LAYOUTCOMMIT with
	loca_reclaim TRUE fails, the pNFS client has lost all the data in		loca_reclaim TRUE fails, the pNFS client has lost all the data in
	the range defined by &lt;loca_offset, loca_length&gt;. A client		the range defined by &lt;loca_offset, loca_length&gt;. A client
	can defend against this risk by caching all data, whether written		can defend against this risk by caching all data, whether written
	synchronously or asynchronously in its memory, and by not releasing the		synchronously or asynchronously in its memory, and by not releasing the
	cached data until a successful LAYOUTCOMMIT. This condition		cached data until a successful LAYOUTCOMMIT. This condition
	does not hold true for all layout types; for example, file-based		does not hold true for all layout types; for example, file-based
	storage devices need not suffer from this limitation.		storage devices need not suffer from this limitation.
	</t>		</t>
	<t>		</li>
			<li>
	The client does not have a copy of the data in its memory and the		The client does not have a copy of the data in its memory and the
	metadata server is no longer in its grace period; i.e., the metadata		metadata server is no longer in its grace period; i.e., the metadata
	server returns NFS4ERR_NO_GRACE. As with the scenario in the above		server returns NFS4ERR_NO_GRACE. As with the scenario in the above
	bullet point, the failure of LAYOUTCOMMIT means the data		bullet point, the failure of LAYOUTCOMMIT means the data
	in the range &lt;loca_offset, loca_length&gt; lost. The		in the range &lt;loca_offset, loca_length&gt; lost. The
	defense against the risk is the same -- cache all written data		defense against the risk is the same -- cache all written data
	on the client until a successful LAYOUTCOMMIT.		on the client until a successful LAYOUTCOMMIT.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section anchor="pnfs_grace_exception" numbered="true" toc="default">
	<section title="Operations during Metadata Server Grace Period"		<name>Operations during Metadata Server Grace Period</name>
	anchor="pnfs_grace_exception">		<t>
	<t>
	Some of the recovery scenarios thus far noted that some		Some of the recovery scenarios thus far noted that some
	operations (namely, WRITE and LAYOUTGET) might be permitted during		operations (namely, WRITE and LAYOUTGET) might be permitted during
	the metadata server's grace period. The metadata server may allow		the metadata server's grace period. The metadata server may allow
	these operations during its grace period. For LAYOUTGET, the		these operations during its grace period. For LAYOUTGET, the
	metadata server must reliably determine that servicing such a		metadata server must reliably determine that servicing such a
	request will not conflict with an impending LAYOUTCOMMIT reclaim		request will not conflict with an impending LAYOUTCOMMIT reclaim
	request. For WRITE, the metadata server		request. For WRITE, the metadata server
	must reliably determine that servicing the request		must reliably determine that servicing the request
	will not conflict with an impending OPEN or with a LOCK where the		will not conflict with an impending OPEN or with a LOCK where the
	file has mandatory byte-range locking enabled.		file has mandatory byte-range locking enabled.
	</t>		</t>
	<t>		<t>
	As mentioned previously, for expediency,		As mentioned previously, for expediency,
	the metadata server might reject some		the metadata server might reject some
	operations (namely, WRITE and LAYOUTGET) during its		operations (namely, WRITE and LAYOUTGET) during its
	grace period, because the simplest correct approach		grace period, because the simplest correct approach
	is to reject all non-reclaim pNFS requests and WRITE operations by		is to reject all non-reclaim pNFS requests and WRITE operations by
	returning the NFS4ERR_GRACE error. However, depending on the		returning the NFS4ERR_GRACE error. However, depending on the
	storage protocol (which is specific to the layout type) and		storage protocol (which is specific to the layout type) and
	metadata server implementation, the metadata server may be able to		metadata server implementation, the metadata server may be able to
	determine that a particular request is safe. For example, a		determine that a particular request is safe. For example, a
	metadata server may save provisional allocation mappings for each		metadata server may save provisional allocation mappings for each
	file to stable storage, as well as information about potentially		file to stable storage, as well as information about potentially
	conflicting OPEN share modes and mandatory byte-range locks that might		conflicting OPEN share modes and mandatory byte-range locks that might
	have been in effect at the time of restart, and the metadata		have been in effect at the time of restart, and the metadata
	server may use this information during the recovery grace period to determin e that a		server may use this information during the recovery grace period to determin e that a
	WRITE request is safe.		WRITE request is safe.
	</t>		</t>
	</section>		</section>
			<section anchor="storage_device_recovery" numbered="true" toc="default">
	<section anchor="storage_device_recovery" title="Storage Device Recovery">		<name>Storage Device Recovery</name>
	<t>		<t>
	Recovery from storage device restart is mostly dependent upon the layout type		Recovery from storage device restart is mostly dependent upon the layout type
	in use. However, there are a few general techniques a client can		in use. However, there are a few general techniques a client can
	use if it discovers a storage device has crashed while holding		use if it discovers a storage device has crashed while holding
	modified, uncommitted data that was asynchronously written.		modified, uncommitted data that was asynchronously written.
	First and foremost, it		First and foremost, it
	is important to realize that the client is the only one that has the		is important to realize that the client is the only one that has the
	information necessary to recover non-committed data since		information necessary to recover non-committed data since
	it holds the modified data and probably nothing else does. Second,		it holds the modified data and probably nothing else does. Second,
	the best solution is for the client to err on the side of caution		the best solution is for the client to err on the side of caution
	and attempt to rewrite the modified data through another path.		and attempt to rewrite the modified data through another path.
	</t>		</t>
	<t>		<t>
	The client SHOULD immediately WRITE the data to the metadata server,		The client <bcp14>SHOULD</bcp14> immediately WRITE the data to the metadata se
			rver,
	with the stable field in the WRITE4args set to FILE_SYNC4. Once it		with the stable field in the WRITE4args set to FILE_SYNC4. Once it
	does this, there is no need to wait for the original storage device.		does this, there is no need to wait for the original storage device.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="Metadata and Storage Device Roles">		<name>Metadata and Storage Device Roles</name>
	<t>		<t>
	If the same physical hardware is used to implement both a		If the same physical hardware is used to implement both a
	metadata server and storage device, then the same hardware		metadata server and storage device, then the same hardware
	entity is to be understood to be implementing two		entity is to be understood to be implementing two
	distinct roles and it is important that it be clearly		distinct roles and it is important that it be clearly
	understood on behalf of which role the hardware is		understood on behalf of which role the hardware is
	executing at any given time.		executing at any given time.
	</t>		</t>
	<t>		<t>
	Two sub-cases can be distinguished.		Two sub-cases can be distinguished.
	<list style="numbers">		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	The storage device uses NFSv4.1 as the storage protocol, i.e., the same		The storage device uses NFSv4.1 as the storage protocol, i.e., the same
	physical hardware is used to implement both a metadata and data		physical hardware is used to implement both a metadata and data
	server. See <xref target="pnfs_session_stuff" />		server. See <xref target="pnfs_session_stuff" format="default"/>
	for a description of how multiple roles are handled.		for a description of how multiple roles are handled.
	</t>		</li>
			<li>
	<t>
	The storage device does not use NFSv4.1 as the storage protocol,		The storage device does not use NFSv4.1 as the storage protocol,
	and the same physical hardware is used to implement both a		and the same physical hardware is used to implement both a
	metadata and storage device. Whether distinct network addresses		metadata and storage device. Whether distinct network addresses
	are used to access the metadata server and storage device is		are used to access the metadata server and storage device is
	immaterial. This is because it is always clear to the pNFS client and		immaterial. This is because it is always clear to the pNFS client and
	server, from the upper-layer protocol being used (NFSv4.1 or		server, from the upper-layer protocol being used (NFSv4.1 or
	non-NFSv4.1), to which role the request to the common server network		non-NFSv4.1), to which role the request to the common server network
	address is directed.		address is directed.
	</t>		</li>
	</list>		</ol>
	</t>		</section>
	</section>		<section anchor="security_considerations_pnfs" numbered="true" toc="defaul
			t">
	<section title="Security Considerations for pNFS" anchor="security_consideration		<name>Security Considerations for pNFS</name>
	s_pnfs">		<t>
	<t>
	pNFS separates file system metadata and data and provides access to		pNFS separates file system metadata and data and provides access to
	both. There are pNFS-specific operations (listed in		both. There are pNFS-specific operations (listed in
	<xref target="pnfs_ops" />) that provide access to the metadata; all		<xref target="pnfs_ops" format="default"/>) that provide access to the metadat a; all
	existing NFSv4.1 conventional (non-pNFS) security mechanisms and		existing NFSv4.1 conventional (non-pNFS) security mechanisms and
	features apply to accessing the metadata. The combination of		features apply to accessing the metadata. The combination of
	components in a pNFS system (see <xref target="fig_system" />) is		components in a pNFS system (see <xref target="fig_system" format="default"/>) is
	required to preserve the security properties of NFSv4.1 with respect		required to preserve the security properties of NFSv4.1 with respect
	to an entity that is accessing a storage device from a client, including		to an entity that is accessing a storage device from a client, including
	security countermeasures to defend against threats for which NFSv4.1		security countermeasures to defend against threats for which NFSv4.1
	provides defenses in environments where these threats are		provides defenses in environments where these threats are
	considered significant.		considered significant.
	</t>		</t>
	<t>		<t>
	In some cases, the security countermeasures for connections		In some cases, the security countermeasures for connections
	to storage devices may take the form of physical isolation or a		to storage devices may take the form of physical isolation or a
	recommendation to avoid the use of pNFS in an environment. For example, it		recommendation to avoid the use of pNFS in an environment. For example, it
	may be impractical to provide confidentiality protection for some		may be impractical to provide confidentiality protection for some
	storage protocols to protect against eavesdropping. In		storage protocols to protect against eavesdropping. In
	environments where eavesdropping on such protocols is of sufficient		environments where eavesdropping on such protocols is of sufficient
	concern to require countermeasures, physical isolation of the		concern to require countermeasures, physical isolation of the
	communication channel (e.g., via direct connection from client(s)		communication channel (e.g., via direct connection from client(s)
	to storage device(s)) and/or a decision to forgo use of pNFS (e.g.,		to storage device(s)) and/or a decision to forgo use of pNFS (e.g.,
	and fall back to conventional NFSv4.1) may be appropriate courses of action.		and fall back to conventional NFSv4.1) may be appropriate courses of action.
	</t>		</t>
	<t>		<t>
	Where communication with storage devices is subject to the same		Where communication with storage devices is subject to the same
	threats as client-to-metadata server communication, the protocols		threats as client-to-metadata server communication, the protocols
	used for that communication need to provide security mechanisms as		used for that communication need to provide security mechanisms as
	strong as or no weaker than those available via RPCSEC_GSS for		strong as or no weaker than those available via RPCSEC_GSS for
	NFSv4.1. Except for the storage protocol used for the LAYOUT4_NFSV4_1_FILES		NFSv4.1. Except for the storage protocol used for the LAYOUT4_NFSV4_1_FILES
	layout (see <xref target="file_layout_type"/>), i.e., except for NFSv4.1,		layout (see <xref target="file_layout_type" format="default"/>), i.e., except for NFSv4.1,
	it is beyond the scope of this document to specify the security mechanisms		it is beyond the scope of this document to specify the security mechanisms
	for storage access protocols.		for storage access protocols.
	</t>		</t>
	<t>		<t>
	pNFS implementations MUST NOT remove NFSv4.1's access controls.		pNFS implementations <bcp14>MUST NOT</bcp14> remove NFSv4.1's access controls.
	The combination of clients, storage devices, and the metadata server		The combination of clients, storage devices, and the metadata server
	are responsible for ensuring that all client-to-storage-device file		are responsible for ensuring that all client-to-storage-device file
	data access respects NFSv4.1's ACLs and file open modes. This entails		data access respects NFSv4.1's ACLs and file open modes. This entails
	performing both of these checks on every access in the client, the		performing both of these checks on every access in the client, the
	storage device, or both (as applicable; when the storage device is		storage device, or both (as applicable; when the storage device is
	an NFSv4.1 server, the storage device is ultimately responsible for		an NFSv4.1 server, the storage device is ultimately responsible for
	controlling access as described in <xref target="state_propagation"/>).		controlling access as described in <xref target="state_propagation" format="de fault"/>).
	If a pNFS configuration performs these checks only in the client,		If a pNFS configuration performs these checks only in the client,
	the risk of a misbehaving client obtaining unauthorized access is		the risk of a misbehaving client obtaining unauthorized access is
	an important consideration in determining when it is appropriate to		an important consideration in determining when it is appropriate to
	use such a pNFS configuration. Such layout types SHOULD NOT be used		use such a pNFS configuration. Such layout types <bcp14>SHOULD NOT</bcp14> be used
	when client-only access checks do not provide sufficient assurance		when client-only access checks do not provide sufficient assurance
	that NFSv4.1 access control is being applied correctly. (This		that NFSv4.1 access control is being applied correctly. (This
	is not a problem for the file layout type described in <xref		is not a problem for the file layout type described in <xref target="file_layo
	target="file_layout_type"/> because the storage access protocol for		ut_type" format="default"/> because the storage access protocol for
	LAYOUT4_NFSV4_1_FILES is NFSv4.1, and thus the security model for		LAYOUT4_NFSV4_1_FILES is NFSv4.1, and thus the security model for
	storage device access via LAYOUT4_NFSv4_1_FILES is the same as that		storage device access via LAYOUT4_NFSv4_1_FILES is the same as that
	of the metadata server.) For handling of access control specific to		of the metadata server.) For handling of access control specific to
	a layout, the reader should examine the layout specification, such as		a layout, the reader should examine the layout specification, such as
	the <xref target="file_layout_type">NFSv4.1/file-based layout</xref>		the <xref target="file_layout_type" format="default">NFSv4.1/file-based layout
	of this document, the <xref target="RFC5663">blocks		</xref>
	layout</xref>, and <xref target="RFC5664">objects		of this document, the <xref target="RFC5663" format="default">blocks
			layout</xref>, and <xref target="RFC5664" format="default">objects
	layout</xref>.		layout</xref>.
	</t>		</t>
	</section>		</section>
			</section>
	</section>		<section anchor="file_layout_type" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp $		<name>NFSv4.1 as a Storage Protocol in pNFS: the File Layout Type</name>
	-->		<t>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section title="NFSv4.1 as a Storage Protocol in pNFS: the File Layout Type" anc
	hor="file_layout_type">
	<t>
	This section describes the semantics and format of NFSv4.1 file-based		This section describes the semantics and format of NFSv4.1 file-based
	layouts for pNFS.		layouts for pNFS.
	NFSv4.1 file-based layouts use the LAYOUT4_NFSV4_1_FILES layout type.		NFSv4.1 file-based layouts use the LAYOUT4_NFSV4_1_FILES layout type.
	The LAYOUT4_NFSV4_1_FILES type defines		The LAYOUT4_NFSV4_1_FILES type defines
	striping data across multiple NFSv4.1 data servers.		striping data across multiple NFSv4.1 data servers.
	</t>		</t>
	<section title="Client ID and Session Considerations" anchor="pnfs_session_stuf		<section anchor="pnfs_session_stuff" numbered="true" toc="default">
	f">		<name>Client ID and Session Considerations</name>
	<t>		<t>
	Sessions are a REQUIRED feature of NFSv4.1, and this		Sessions are a <bcp14>REQUIRED</bcp14> feature of NFSv4.1, and this
	extends to both the metadata server and file-based (NFSv4.1-based)		extends to both the metadata server and file-based (NFSv4.1-based)
	data servers.		data servers.
	</t>		</t>
	<t>		<t>
	The role a server plays in pNFS is determined by the result it returns		The role a server plays in pNFS is determined by the result it returns
	from EXCHANGE_ID.		from EXCHANGE_ID.
	The roles are:		The roles are:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Metadata server (EXCHGID4_FLAG_USE_PNFS_MDS is set in the result eir_flags).		Metadata server (EXCHGID4_FLAG_USE_PNFS_MDS is set in the result eir_flags).
	</t>		</li>
			<li>
	<t>
	Data server (EXCHGID4_FLAG_USE_PNFS_DS).		Data server (EXCHGID4_FLAG_USE_PNFS_DS).
	</t>		</li>
			<li>
	<t>
	Non-metadata server (EXCHGID4_FLAG_USE_NON_PNFS). This is an NFSv4.1		Non-metadata server (EXCHGID4_FLAG_USE_NON_PNFS). This is an NFSv4.1
	server that does not support operations (e.g.,		server that does not support operations (e.g.,
	LAYOUTGET) or attributes that pertain to pNFS.		LAYOUTGET) or attributes that pertain to pNFS.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		The client <bcp14>MAY</bcp14> request zero or more of
	The client MAY request zero or more of
	EXCHGID4_FLAG_USE_NON_PNFS,		EXCHGID4_FLAG_USE_NON_PNFS,
	EXCHGID4_FLAG_USE_PNFS_DS, or		EXCHGID4_FLAG_USE_PNFS_DS, or
	EXCHGID4_FLAG_USE_PNFS_MDS, even though some combinations		EXCHGID4_FLAG_USE_PNFS_MDS, even though some combinations
	(e.g., EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS) are		(e.g., EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS) are
	contradictory. However, the server MUST only return the following		contradictory. However, the server <bcp14>MUST</bcp14> only return the follow ing
	acceptable combinations:		acceptable combinations:
	</t>		</t>
			<table align="center">
	<texttable>		<thead>
			<tr>
	<ttcol>Acceptable Results from EXCHANGE_ID</ttcol>		<th align="left">Acceptable Results from EXCHANGE_ID</th>
			</tr>
	<c>		</thead>
			<tbody>
			<tr>
			<td align="left">
	EXCHGID4_FLAG_USE_PNFS_MDS		EXCHGID4_FLAG_USE_PNFS_MDS
	</c>		</td>
			</tr>
	<c>		<tr>
			<td align="left">
	EXCHGID4_FLAG_USE_PNFS_MDS | EXCHGID4_FLAG_USE_PNFS_DS		EXCHGID4_FLAG_USE_PNFS_MDS | EXCHGID4_FLAG_USE_PNFS_DS
	</c>		</td>
			</tr>
	<c>		<tr>
			<td align="left">
	EXCHGID4_FLAG_USE_PNFS_DS		EXCHGID4_FLAG_USE_PNFS_DS
	</c>		</td>
			</tr>
	<c>		<tr>
			<td align="left">
	EXCHGID4_FLAG_USE_NON_PNFS		EXCHGID4_FLAG_USE_NON_PNFS
	</c>		</td>
			</tr>
	<c>		<tr>
			<td align="left">
	EXCHGID4_FLAG_USE_PNFS_DS | EXCHGID4_FLAG_USE_NON_PNFS		EXCHGID4_FLAG_USE_PNFS_DS | EXCHGID4_FLAG_USE_NON_PNFS
	</c>		</td>
	</texttable>		</tr>
	<t>		</tbody>
			</table>
			<t>
	As the above table implies, a server can have one		As the above table implies, a server can have one
	or two roles. A server can be both a metadata server		or two roles. A server can be both a metadata server
	and a data server, or it can be both a data server and		and a data server, or it can be both a data server and
	non-metadata server. In addition to returning two roles		non-metadata server. In addition to returning two roles
	in the EXCHANGE_ID's results, and thus serving both roles		in the EXCHANGE_ID's results, and thus serving both roles
	via a common client ID, a server can serve two roles		via a common client ID, a server can serve two roles
	by returning a unique client ID and server owner for		by returning a unique client ID and server owner for
	each role in each of two EXCHANGE_ID results, with each		each role in each of two EXCHANGE_ID results, with each
	result indicating each role.		result indicating each role.
	</t>		</t>
	<t>		<t>
	In the case of a server with concurrent pNFS roles that		In the case of a server with concurrent pNFS roles that
	are served by a common client ID, if the EXCHANGE_ID		are served by a common client ID, if the EXCHANGE_ID
	request from the client has zero or a combination of the		request from the client has zero or a combination of the
	bits set in eia_flags, the server result should set bits		bits set in eia_flags, the server result should set bits
	that represent the higher of the acceptable combination		that represent the higher of the acceptable combination
	of the server roles, with a preference to match the roles		of the server roles, with a preference to match the roles
	requested by the client. Thus, if a client request has		requested by the client. Thus, if a client request has
	(EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS		(EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS
	| EXCHGID4_FLAG_USE_PNFS_DS) flags set, and the server		| EXCHGID4_FLAG_USE_PNFS_DS) flags set, and the server
	is both a metadata server and a data server, serving		is both a metadata server and a data server, serving
	both the roles by a common client ID, the server		both the roles by a common client ID, the server
	SHOULD return with (EXCHGID4_FLAG_USE_PNFS_MDS |		<bcp14>SHOULD</bcp14> return with (EXCHGID4_FLAG_USE_PNFS_MDS |
	EXCHGID4_FLAG_USE_PNFS_DS) set.		EXCHGID4_FLAG_USE_PNFS_DS) set.
	</t>		</t>
	<t>		<t>
	In the case of a server that has multiple concurrent		In the case of a server that has multiple concurrent
	pNFS roles, each role served by a unique client ID,		pNFS roles, each role served by a unique client ID,
	if the client specifies zero or a combination of roles		if the client specifies zero or a combination of roles
	in the request, the server results SHOULD return only		in the request, the server results <bcp14>SHOULD</bcp14> return only
	one of the roles from the combination specified by the		one of the roles from the combination specified by the
	client request. If the role specified by the server		client request. If the role specified by the server
	result does not match the intended use by the client,		result does not match the intended use by the client,
	the client should send the EXCHANGE_ID specifying just		the client should send the EXCHANGE_ID specifying just
	the interested pNFS role.		the interested pNFS role.
	</t>		</t>
			<t>
	<t>
	If a pNFS metadata client gets a layout that refers it to an NFSv4.1		If a pNFS metadata client gets a layout that refers it to an NFSv4.1
	data server, it needs a client ID on that data server. If it does not		data server, it needs a client ID on that data server. If it does not
	yet have a client ID from the server that had the EXCHGID4_FLAG_USE_PNFS_DS		yet have a client ID from the server that had the EXCHGID4_FLAG_USE_PNFS_DS
	flag set in the EXCHANGE_ID results, then the client needs to		flag set in the EXCHANGE_ID results, then the client needs to
	send an EXCHANGE_ID to the data server, using		send an EXCHANGE_ID to the data server, using
	the same co_ownerid as it sent to the metadata server, with the		the same co_ownerid as it sent to the metadata server, with the
	EXCHGID4_FLAG_USE_PNFS_DS flag set in the arguments.		EXCHGID4_FLAG_USE_PNFS_DS flag set in the arguments.
	If the server's		If the server's
	EXCHANGE_ID results have EXCHGID4_FLAG_USE_PNFS_DS set, then the		EXCHANGE_ID results have EXCHGID4_FLAG_USE_PNFS_DS set, then the
	client may use the client ID to create sessions that will		client may use the client ID to create sessions that will
	exchange pNFS data operations.		exchange pNFS data operations.
	The client ID returned by the data server has no relationship with		The client ID returned by the data server has no relationship with
	the client ID returned by a metadata server unless the client IDs		the client ID returned by a metadata server unless the client IDs
	are equal, and the server owners and server scopes of the data server		are equal, and the server owners and server scopes of the data server
	and metadata server are equal.		and metadata server are equal.
	</t>		</t>
	<t>		<t>
	In NFSv4.1, the		In NFSv4.1, the
	session ID in the SEQUENCE operation implies the		session ID in the SEQUENCE operation implies the
	client ID, which in turn might be used by the server to		client ID, which in turn might be used by the server to
	map the stateid to the right client/server pair.		map the stateid to the right client/server pair.
	However, when a data server is presented with a READ or		However, when a data server is presented with a READ or
	WRITE operation with a stateid, because the		WRITE operation with a stateid, because the
	stateid is associated with a		stateid is associated with a
	client ID on a metadata server, and because the session ID in		client ID on a metadata server, and because the session ID in
	the preceding SEQUENCE operation is tied to the		the preceding SEQUENCE operation is tied to the
	client ID of the data server, the data server has no		client ID of the data server, the data server has no
	obvious way to determine the metadata server from the		obvious way to determine the metadata server from the
	COMPOUND procedure, and thus has no way to validate the		COMPOUND procedure, and thus has no way to validate the
	stateid. One RECOMMENDED approach is for pNFS servers to		stateid. One <bcp14>RECOMMENDED</bcp14> approach is for pNFS servers to
	encode metadata server routing and/or identity		encode metadata server routing and/or identity
	information in the data server filehandles as returned		information in the data server filehandles as returned
	in the layout.		in the layout.
	</t>		</t>
	<t>		<t>
	If metadata server routing and/or identity information is encoded		If metadata server routing and/or identity information is encoded
	in data server filehandles,		in data server filehandles,
	when the metadata server identity or location		when the metadata server identity or location
	changes, the data server filehandles it gave out will become		changes, the data server filehandles it gave out will become
	invalid (stale), and so the metadata server MUST first		invalid (stale), and so the metadata server <bcp14>MUST</bcp14> first
	recall the layouts.		recall the layouts.
	Invalidating a data server filehandle does not render		Invalidating a data server filehandle does not render
	the NFS client's data cache invalid. The client's cache should		the NFS client's data cache invalid. The client's cache should
	map a data server filehandle to a metadata server filehandle, and		map a data server filehandle to a metadata server filehandle, and
	a metadata server filehandle to cached data.		a metadata server filehandle to cached data.
	</t>		</t>
			<t>
	<t>
	If a server is both a metadata server and a data server,		If a server is both a metadata server and a data server,
	the server might need to distinguish operations on		the server might need to distinguish operations on
	files that are directed to the metadata server from		files that are directed to the metadata server from
	those that are directed to the data server. It is		those that are directed to the data server. It is
	RECOMMENDED that the values of the filehandles returned by		<bcp14>RECOMMENDED</bcp14> that the values of the filehandles returned by
	the LAYOUTGET operation be different than the value		the LAYOUTGET operation be different than the value
	of the filehandle returned by the OPEN of the same file.		of the filehandle returned by the OPEN of the same file.
	</t>		</t>
	<t>		<t>
	Another scenario is for the metadata server and the		Another scenario is for the metadata server and the
	storage device to be distinct from one client's point of		storage device to be distinct from one client's point of
	view, and the roles reversed from another client's point		view, and the roles reversed from another client's point
	of view. For example, in the cluster file system model,		of view. For example, in the cluster file system model,
	a metadata server to one client might be a data server to		a metadata server to one client might be a data server to
	another client. If NFSv4.1 is being used as the storage		another client. If NFSv4.1 is being used as the storage
	protocol, then pNFS servers need to encode the values		protocol, then pNFS servers need to encode the values
	of filehandles according to their specific roles.		of filehandles according to their specific roles.
	</t>		</t>
	<section anchor="dsonly" title="Sessions Considerations for Data Servers">		<section anchor="dsonly" numbered="true" toc="default">
	<t>		<name>Sessions Considerations for Data Servers</name>
			<t>
	<xref target="Obligations_of_the_Client" /> states		<xref target="Obligations_of_the_Client" format="default"/> states
	that a client has to keep its lease renewed in		that a client has to keep its lease renewed in
	order to prevent a session from being deleted by		order to prevent a session from being deleted by
	the server. If the reply to EXCHANGE_ID has just the		the server. If the reply to EXCHANGE_ID has just the
	EXCHGID4_FLAG_USE_PNFS_DS role set, then (as noted in		EXCHGID4_FLAG_USE_PNFS_DS role set, then (as noted in
	<xref target="ds_ops"/>) the client will not be able		<xref target="ds_ops" format="default"/>) the client will not be able
	to determine the data server's lease_time attribute		to determine the data server's lease_time attribute
	because GETATTR will not be permitted. Instead, the		because GETATTR will not be permitted. Instead, the
	rule is that any time a client receives a layout		rule is that any time a client receives a layout
	referring it to a data server that returns just		referring it to a data server that returns just
	the EXCHGID4_FLAG_USE_PNFS_DS role, the client MAY		the EXCHGID4_FLAG_USE_PNFS_DS role, the client <bcp14>MAY</bcp14>
	assume that the lease_time attribute from the metadata		assume that the lease_time attribute from the metadata
	server that returned the layout applies to the data		server that returned the layout applies to the data
	server. Thus, the data server MUST be aware of the values		server. Thus, the data server <bcp14>MUST</bcp14> be aware of the values
	of all lease_time attributes of all metadata servers for which it		of all lease_time attributes of all metadata servers for which it
	is providing I/O, and it MUST use the maximum of all such		is providing I/O, and it <bcp14>MUST</bcp14> use the maximum of all such
	lease_time values as the lease interval for all client		lease_time values as the lease interval for all client
	IDs and sessions established on it.		IDs and sessions established on it.
	</t>		</t>
	<t>		<t>
	For example, if one metadata server has a lease_time		For example, if one metadata server has a lease_time
	attribute of 20 seconds, and a second metadata		attribute of 20 seconds, and a second metadata
	server has a lease_time attribute of 10 seconds,		server has a lease_time attribute of 10 seconds,
	then if both servers return layouts that refer to an		then if both servers return layouts that refer to an
	EXCHGID4_FLAG_USE_PNFS_DS-only data server, the data		EXCHGID4_FLAG_USE_PNFS_DS-only data server, the data
	server MUST renew a client's lease if the interval		server <bcp14>MUST</bcp14> renew a client's lease if the interval
	between two SEQUENCE operations on different COMPOUND		between two SEQUENCE operations on different COMPOUND
	requests is less than 20 seconds.		requests is less than 20 seconds.
	</t>		</t>
			</section>
	</section>		</section>
			<section anchor="file_layout_definitions" numbered="true" toc="default">
	</section>		<name>File Layout Definitions</name>
			<t>
	<section title="File Layout Definitions" anchor="file_layout_definitions">
	<t>
	The following definitions apply to the LAYOUT4_NFSV4_1_FILES		The following definitions apply to the LAYOUT4_NFSV4_1_FILES
	layout type and may be applicable to other layout types.		layout type and may be applicable to other layout types.
	<list style='hanging'>
	<t hangText="Unit.">
	A unit is a fixed-size quantity of data written to a data server.
	</t>		</t>
	<t hangText="Pattern.">		<dl newline="false" spacing="normal">
			<dt>Unit.</dt>
			<dd>
			A unit is a fixed-size quantity of data written to a data server.
			</dd>
			<dt>Pattern.</dt>
			<dd>
	A pattern is a method of distributing one or more		A pattern is a method of distributing one or more
	equal sized units across a set of data servers.		equal sized units across a set of data servers.
	A pattern is iterated one or more times.		A pattern is iterated one or more times.
	</t>		</dd>
	<t hangText="Stripe.">		<dt>Stripe.</dt>
			<dd>
	A stripe is a set of data distributed		A stripe is a set of data distributed
	across a set of data servers in a		across a set of data servers in a
	pattern before that pattern repeats.		pattern before that pattern repeats.
	</t>		</dd>
	<t hangText="Stripe Count.">		<dt>Stripe Count.</dt>
			<dd>
	A stripe count is the number of units in a pattern.		A stripe count is the number of units in a pattern.
	</t>		</dd>
	<t hangText="Stripe Width.">		<dt>Stripe Width.</dt>
			<dd>
	A stripe width is the size of a stripe in bytes.		A stripe width is the size of a stripe in bytes.
	The stripe width = the stripe count * the size of the stripe unit.		The stripe width = the stripe count * the size of the stripe unit.
	</t>		</dd>
	</list>		</dl>
			<t>
	Hereafter, this document will refer to a unit that is a written		Hereafter, this document will refer to a unit that is a written
	in a pattern as a "stripe unit".		in a pattern as a "stripe unit".
	</t>		</t>
	<t>		<t>
	A pattern may have more stripe units than data servers.		A pattern may have more stripe units than data servers.
	If so, some data servers will have more than one stripe unit		If so, some data servers will have more than one stripe unit
	per stripe. A data server that has multiple stripe		per stripe. A data server that has multiple stripe
	units per stripe MAY store each unit in a different data file (and		units per stripe <bcp14>MAY</bcp14> store each unit in a different data file ( and
	depending on the implementation, will possibly assign a unique data		depending on the implementation, will possibly assign a unique data
	filehandle to each data file).		filehandle to each data file).
	</t>		</t>
	</section> <!-- "File Striping Definitions" "file_layout_definitions" -->		</section>
	<section title="File Layout Data Types" anchor="file_data_types">		<section anchor="file_data_types" numbered="true" toc="default">
	<t>		<name>File Layout Data Types</name>
			<t>
	The high level NFSv4.1 layout types are		The high level NFSv4.1 layout types are
	nfsv4_1_file_layouthint4,		nfsv4_1_file_layouthint4,
	nfsv4_1_file_layout_ds_addr4,		nfsv4_1_file_layout_ds_addr4,
	and nfsv4_1_file_layout4.		and nfsv4_1_file_layout4.
	</t>		</t>
			<t>
	<t>
	The SETATTR operation supports a layout hint attribute		The SETATTR operation supports a layout hint attribute
	(<xref target="attrdef_layout_hint" />).		(<xref target="attrdef_layout_hint" format="default"/>).
	When the client sets a layout hint (data type layouthint4) with		When the client sets a layout hint (data type layouthint4) with
	a layout type of LAYOUT4_NFSV4_1_FILES (the loh_type field),		a layout type of LAYOUT4_NFSV4_1_FILES (the loh_type field),
	the loh_body field contains a value of data type		the loh_body field contains a value of data type
	nfsv4_1_file_layouthint4.		nfsv4_1_file_layouthint4.
	</t>		</t>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	const NFL4_UFLG_MASK = 0x0000003F;		const NFL4_UFLG_MASK = 0x0000003F;
	const NFL4_UFLG_DENSE = 0x00000001;		const NFL4_UFLG_DENSE = 0x00000001;
	const NFL4_UFLG_COMMIT_THRU_MDS = 0x00000002;		const NFL4_UFLG_COMMIT_THRU_MDS = 0x00000002;
	const NFL4_UFLG_STRIPE_UNIT_SIZE_MASK		const NFL4_UFLG_STRIPE_UNIT_SIZE_MASK
	= 0xFFFFFFC0;		= 0xFFFFFFC0;
	typedef uint32_t nfl_util4;		typedef uint32_t nfl_util4;
	</artwork>
	</figure>
	<figure>
	<artwork>
	enum filelayout_hint_care4 {		enum filelayout_hint_care4 {
	NFLH4_CARE_DENSE = NFL4_UFLG_DENSE,		NFLH4_CARE_DENSE = NFL4_UFLG_DENSE,
	NFLH4_CARE_COMMIT_THRU_MDS		NFLH4_CARE_COMMIT_THRU_MDS
	= NFL4_UFLG_COMMIT_THRU_MDS,		= NFL4_UFLG_COMMIT_THRU_MDS,
	NFLH4_CARE_STRIPE_UNIT_SIZE		NFLH4_CARE_STRIPE_UNIT_SIZE
	= 0x00000040,		= 0x00000040,
	NFLH4_CARE_STRIPE_COUNT = 0x00000080		NFLH4_CARE_STRIPE_COUNT = 0x00000080
	};		};
	/* Encoded in the loh_body field of data type layouthint4: */		/* Encoded in the loh_body field of data type layouthint4: */
	struct nfsv4_1_file_layouthint4 {		struct nfsv4_1_file_layouthint4 {
	uint32_t nflh_care;		uint32_t nflh_care;
	nfl_util4 nflh_util;		nfl_util4 nflh_util;
	count4 nflh_stripe_count;		count4 nflh_stripe_count;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The generic layout hint structure is described		The generic layout hint structure is described
	in <xref target="layouthint4" />. The client uses the		in <xref target="layouthint4" format="default"/>. The client uses the
	layout hint in the layout_hint (<xref		layout hint in the layout_hint (<xref target="attrdef_layout_hint" format="
	target="attrdef_layout_hint" />) attribute to indicate the preferred type		default"/>) attribute to indicate the preferred type
	of layout to be used for a newly created file. The		of layout to be used for a newly created file. The
	LAYOUT4_NFSV4_1_FILES layout-type-specific content for the		LAYOUT4_NFSV4_1_FILES layout-type-specific content for the
	layout hint is composed of three fields. The first field,		layout hint is composed of three fields. The first field,
	nflh_care, is a set of flags indicating which values of the hint the		nflh_care, is a set of flags indicating which values of the hint the
	client cares about. If the NFLH4_CARE_DENSE flag is set, then		client cares about. If the NFLH4_CARE_DENSE flag is set, then
	the client indicates in the second field, nflh_util,		the client indicates in the second field, nflh_util,
	a preference for how the data		a preference for how the data
	file is packed (<xref target="sparse_dense" />), which is controlled		file is packed (<xref target="sparse_dense" format="default"/>), which is c ontrolled
	by the value of the expression nflh_util &amp; NFL4_UFLG_DENSE ("&amp;" rep resents the bitwise AND operator). If the		by the value of the expression nflh_util &amp; NFL4_UFLG_DENSE ("&amp;" rep resents the bitwise AND operator). If the
	NFLH4_CARE_COMMIT_THRU_MDS flag is set, then the client indicates		NFLH4_CARE_COMMIT_THRU_MDS flag is set, then the client indicates
	a preference for whether the client should send COMMIT operations		a preference for whether the client should send COMMIT operations
	to the metadata server or data server (<xref target="commit_thru_mds" />),		to the metadata server or data server (<xref target="commit_thru_mds" forma t="default"/>),
	which is controlled by the value of nflh_util &amp; NFL4_UFLG_COMMIT_THRU_M DS.		which is controlled by the value of nflh_util &amp; NFL4_UFLG_COMMIT_THRU_M DS.
	If the NFLH4_CARE_STRIPE_UNIT_SIZE flag is set, the client indicates		If the NFLH4_CARE_STRIPE_UNIT_SIZE flag is set, the client indicates
	its preferred stripe unit size, which is indicated in		its preferred stripe unit size, which is indicated in
	nflh_util &amp;		nflh_util &amp;
	NFL4_UFLG_STRIPE_UNIT_SIZE_MASK (thus, the stripe		NFL4_UFLG_STRIPE_UNIT_SIZE_MASK (thus, the stripe
	unit size MUST be a multiple of 64 bytes). The minimum stripe unit		unit size <bcp14>MUST</bcp14> be a multiple of 64 bytes). The minimum strip e unit
	size is 64 bytes.		size is 64 bytes.
	If the NFLH4_CARE_STRIPE_COUNT flag is set, the client indicates		If the NFLH4_CARE_STRIPE_COUNT flag is set, the client indicates
	in the third field,		in the third field,
	nflh_stripe_count, the stripe count. The stripe count multiplied		nflh_stripe_count, the stripe count. The stripe count multiplied
	by the stripe unit size is the stripe width.		by the stripe unit size is the stripe width.
	</t>		</t>
	<t>		<t>
	When LAYOUTGET returns a LAYOUT4_NFSV4_1_FILES layout		When LAYOUTGET returns a LAYOUT4_NFSV4_1_FILES layout
	(indicated in the loc_type field of the lo_content field),		(indicated in the loc_type field of the lo_content field),
	the loc_body field of the lo_content field		the loc_body field of the lo_content field
	contains a value of data type nfsv4_1_file_layout4.		contains a value of data type nfsv4_1_file_layout4.
	Among other content, nfsv4_1_file_layout4 has a storage		Among other content, nfsv4_1_file_layout4 has a storage
	device ID (field nfl_deviceid) of data type		device ID (field nfl_deviceid) of data type
	deviceid4.		deviceid4.
	The GETDEVICEINFO operation maps a device ID to		The GETDEVICEINFO operation maps a device ID to
	a storage device address (type device_addr4). When GETDEVICEINFO		a storage device address (type device_addr4). When GETDEVICEINFO
	returns a device address with a layout type of LAYOUT4_NFSV4_1_FILES		returns a device address with a layout type of LAYOUT4_NFSV4_1_FILES
	(the da_layout_type field), the da_addr_body field contains		(the da_layout_type field), the da_addr_body field contains
	a value of data type nfsv4_1_file_layout_ds_addr4.		a value of data type nfsv4_1_file_layout_ds_addr4.
	</t>		</t>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>		typedef netaddr4 multipath_list4<>;
	typedef netaddr4 multipath_list4&lt;>;
	/*		/*
	* Encoded in the da_addr_body field of		* Encoded in the da_addr_body field of
	* data type device_addr4:		* data type device_addr4:
	*/		*/
	struct nfsv4_1_file_layout_ds_addr4 {		struct nfsv4_1_file_layout_ds_addr4 {
	uint32_t nflda_stripe_indices&lt;>;		uint32_t nflda_stripe_indices<>;
	multipath_list4 nflda_multipath_ds_list&lt;>;		multipath_list4 nflda_multipath_ds_list<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The nfsv4_1_file_layout_ds_addr4 data type represents the		The nfsv4_1_file_layout_ds_addr4 data type represents the
	device address. It is composed of two fields:		device address. It is composed of two fields:
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	nflda_multipath_ds_list: An array of lists of data servers, where		nflda_multipath_ds_list: An array of lists of data servers, where
	each list can be one or more elements, and each element represents		each list can be one or more elements, and each element represents
	a data server address that may serve equally as the target of I/O operations (see		a data server address that may serve equally as the target of I/O operations (see
	<xref target="file_multipath" />).		<xref target="file_multipath" format="default"/>).
	The length of this array might be different than the stripe count.		The length of this array might be different than the stripe count.
	</t>		</li>
	<t>		<li>
	nflda_stripe_indices: An array of indices used to index into		nflda_stripe_indices: An array of indices used to index into
	nflda_multipath_ds_list. The value of each element of nflda_stripe_indices M UST		nflda_multipath_ds_list. The value of each element of nflda_stripe_indices < bcp14>MUST</bcp14>
	be less than the number of elements in nflda_multipath_ds_list.		be less than the number of elements in nflda_multipath_ds_list.
	Each element of nflda_multipath_ds_list SHOULD be referred to by one		Each element of nflda_multipath_ds_list <bcp14>SHOULD</bcp14> be referred to by one
	or more elements of nflda_stripe_indices.		or more elements of nflda_stripe_indices.
	The number of elements in		The number of elements in
	nflda_stripe_indices is always equal to the stripe count.		nflda_stripe_indices is always equal to the stripe count.
	</t>		</li>
	</list>		</ol>
	</t>		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	/*		/*
	* Encoded in the loc_body field of		* Encoded in the loc_body field of
	* data type layout_content4:		* data type layout_content4:
	*/		*/
	struct nfsv4_1_file_layout4 {		struct nfsv4_1_file_layout4 {
	deviceid4 nfl_deviceid;		deviceid4 nfl_deviceid;
	nfl_util4 nfl_util;		nfl_util4 nfl_util;
	uint32_t nfl_first_stripe_index;		uint32_t nfl_first_stripe_index;
	offset4 nfl_pattern_offset;		offset4 nfl_pattern_offset;
	nfs_fh4 nfl_fh_list&lt;>;		nfs_fh4 nfl_fh_list<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		<t>
	<t>
	The nfsv4_1_file_layout4 data type represents the layout.		The nfsv4_1_file_layout4 data type represents the layout.
	It is composed of the following fields:		It is composed of the following fields:
	<list style='numbers'>		</t>
			<ol spacing="normal" type="1">
	<t>		<li>
	nfl_deviceid: The device ID that maps to a value of type		nfl_deviceid: The device ID that maps to a value of type
	nfsv4_1_file_layout_ds_addr4.		nfsv4_1_file_layout_ds_addr4.
	</t>		</li>
			<li>
	<t>
	nfl_util: Like the nflh_util field of data type nfsv4_1_file_layouthint4,		nfl_util: Like the nflh_util field of data type nfsv4_1_file_layouthint4,
	a compact representation of how the data on a file		a compact representation of how the data on a file
	on each data server is packed, whether the client should send		on each data server is packed, whether the client should send
	COMMIT operations to the metadata server or data server, and the		COMMIT operations to the metadata server or data server, and the
	stripe unit size. If a server returns two or		stripe unit size. If a server returns two or
	more overlapping layouts, each stripe unit size in		more overlapping layouts, each stripe unit size in
	each overlapping layout MUST be the same.		each overlapping layout <bcp14>MUST</bcp14> be the same.
	</t>		</li>
			<li>
	<t>
	nfl_first_stripe_index: The index into the first element		nfl_first_stripe_index: The index into the first element
	of the nflda_stripe_indices array to use.		of the nflda_stripe_indices array to use.
	</t>		</li>
			<li>
	<t>		<t>
	nfl_pattern_offset:		nfl_pattern_offset:
	This field is the logical offset into the file		This field is the logical offset into the file
	where the striping pattern starts. It is required for		where the striping pattern starts. It is required for
	converting the client's logical I/O offset (e.g., the current		converting the client's logical I/O offset (e.g., the current
	offset in a POSIX file descriptor before the read() or write()		offset in a POSIX file descriptor before the read() or write()
	system call is sent) into the stripe unit number (see		system call is sent) into the stripe unit number (see
	<xref target="SUi"/>).		<xref target="SUi" format="default"/>).
	<vspace blankLines='1' />		</t>
			<t>
	If dense packing is used, then nfl_pattern_offset		If dense packing is used, then nfl_pattern_offset
	is also needed to convert the client's logical		is also needed to convert the client's logical
	I/O offset to an offset on the file on the data		I/O offset to an offset on the file on the data
	server corresponding to the stripe unit number (see <xref		server corresponding to the stripe unit number (see <xref target="sparse_de
	target="sparse_dense"/>).		nse" format="default"/>).
	<vspace blankLines='1' />		</t>
			<t>
	Note that nfl_pattern_offset is not always the same as		Note that nfl_pattern_offset is not always the same as
	lo_offset. For example, via the LAYOUTGET operation,		lo_offset. For example, via the LAYOUTGET operation,
	a client might request a layout starting at offset 1000 of a		a client might request a layout starting at offset 1000 of a
	file that has its striping pattern start at offset zero.		file that has its striping pattern start at offset zero.
	<vspace blankLines='1' />		</t>
			</li>
	</t>		<li>
			<t>
	<t>
	nfl_fh_list: An array of data server filehandles for each		nfl_fh_list: An array of data server filehandles for each
	list of data servers in each element of the nflda_multipath_ds_list		list of data servers in each element of the nflda_multipath_ds_list
	array. The number of elements in		array. The number of elements in
	nfl_fh_list depends on whether sparse or dense packing		nfl_fh_list depends on whether sparse or dense packing
	is being used.		is being used.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	If sparse packing is being used, the number of elements in		If sparse packing is being used, the number of elements in
	nfl_fh_list MUST be one of three values:		nfl_fh_list <bcp14>MUST</bcp14> be one of three values:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Zero. This means that filehandles used		Zero. This means that filehandles used
	for each data server are the same as the		for each data server are the same as the
	filehandle returned by the OPEN operation		filehandle returned by the OPEN operation
	from the metadata server.		from the metadata server.
	</t>		</li>
			<li>
	<t>
	One. This means that every data server uses		One. This means that every data server uses
	the same filehandle: what is specified in		the same filehandle: what is specified in
	nfl_fh_list[0].		nfl_fh_list[0].
	</t>		</li>
			<li>
	<t>
	The same number of elements in		The same number of elements in
	nflda_multipath_ds_list. Thus, in this case,		nflda_multipath_ds_list. Thus, in this case,
	when sending an I/O operation to any data server in		when sending an I/O operation to any data server in
	nflda_multipath_ds_list[X], the filehandle		nflda_multipath_ds_list[X], the filehandle
	in nfl_fh_list[X] MUST be used.		in nfl_fh_list[X] <bcp14>MUST</bcp14> be used.
	</t>
	</list>
	See the discussion on sparse packing in <xref target="sparse_dense" />.		</li>
	<vspace blankLines='1' />		</ul>
	</t>		<t>
	<t>		See the discussion on sparse packing in <xref target="sparse_dense" format=
			"default"/>.
			</t>
			</li>
			<li>
			<t>
	If dense packing is being used, the number of elements		If dense packing is being used, the number of elements
	in nfl_fh_list MUST be the same as the number		in nfl_fh_list <bcp14>MUST</bcp14> be the same as the number
	of elements in nflda_stripe_indices. Thus,		of elements in nflda_stripe_indices. Thus,
	when sending an I/O operation to any data server in		when sending an I/O operation to any data server in
	nflda_multipath_ds_list[nflda_stripe_indices[Y]],		nflda_multipath_ds_list[nflda_stripe_indices[Y]],
	the filehandle in nfl_fh_list[Y] MUST be		the filehandle in nfl_fh_list[Y] <bcp14>MUST</bcp14> be
	used. In addition, any time there exists i		used. In addition, any time there exists i
	and j, (i != j), such that the intersection of		and j, (i != j), such that the intersection of
	nflda_multipath_ds_list[nflda_stripe_indices[i]]		nflda_multipath_ds_list[nflda_stripe_indices[i]]
	and nflda_multipath_ds_list[nflda_stripe_indices[j]]		and nflda_multipath_ds_list[nflda_stripe_indices[j]]
	is not empty, then nfl_fh_list[i] MUST NOT equal		is not empty, then nfl_fh_list[i] <bcp14>MUST NOT</bcp14> equal
	nfl_fh_list[j]. In other words, when dense packing		nfl_fh_list[j]. In other words, when dense packing
	is being used, if a data server appears in two or more		is being used, if a data server appears in two or more
	units of a striping pattern, each reference to		units of a striping pattern, each reference to
	the data server MUST use a different filehandle.		the data server <bcp14>MUST</bcp14> use a different filehandle.
	<vspace blankLines='1' />		</t>
			<t>
	Indeed, if there are multiple striping patterns,		Indeed, if there are multiple striping patterns,
	as indicated by the presence of multiple objects of		as indicated by the presence of multiple objects of
	data type layout4 (either returned in one or multiple		data type layout4 (either returned in one or multiple
	LAYOUTGET operations), and a data server is the target		LAYOUTGET operations), and a data server is the target
	of a unit of one pattern and another unit of another		of a unit of one pattern and another unit of another
	pattern, then each reference to each data server MUST		pattern, then each reference to each data server <bcp14>MUST</bcp14>
	use a different filehandle.		use a different filehandle.
	<vspace blankLines='1' />		</t>
			<t>
	See the discussion on dense packing in <xref target="sparse_dense" />.		See the discussion on dense packing in <xref target="sparse_dense" format=" default"/>.
	</t>		</t>
	</list>		</li>
	</t>		</ul>
	</list>		</li>
			</ol>
			<t>
	The details on the interpretation of the layout are in		The details on the interpretation of the layout are in
	<xref target="file_layout_interpret" />.		<xref target="file_layout_interpret" format="default"/>.
	</t>
	</section> <!-- "File Layout Data Types" "file_data_types" -->
	<section title="Interpreting the File Layout"
	anchor="file_layout_interpret">
	<section title="Determining the Stripe Unit Number" anchor="SUi">
	<t>		</t>
			</section>
			<section anchor="file_layout_interpret" numbered="true" toc="default">
			<name>Interpreting the File Layout</name>
			<section anchor="SUi" numbered="true" toc="default">
			<name>Determining the Stripe Unit Number</name>
			<t>
	To find the stripe unit number that corresponds to the client's		To find the stripe unit number that corresponds to the client's
	logical file offset, the pattern offset will also be used. The		logical file offset, the pattern offset will also be used. The
	i'th stripe unit (SUi) is:		i'th stripe unit (SUi) is:
	<figure>		</t>
	<artwork><![CDATA[		<sourcecode type="pseudocode"><![CDATA[
	relative_offset = file_offset - nfl_pattern_offset;		relative_offset = file_offset - nfl_pattern_offset;
	SUi = floor(relative_offset / stripe_unit_size);		SUi = floor(relative_offset / stripe_unit_size);]]></sourcecode>
	]]></artwork>		</section>
	</figure>		<section numbered="true" toc="default">
			<name>Interpreting the File Layout Using Sparse Packing</name>
	</t>		<t>
	</section>
	<section title="Interpreting the File Layout Using Sparse Packing">
	<t>
	When sparse packing is used, the algorithm for determining the filehandle and set		When sparse packing is used, the algorithm for determining the filehandle and set
	of data-server network addresses to write stripe unit i		of data-server network addresses to write stripe unit i
	(SUi) to is:		(SUi) to is:
	</t>		</t>
	<figure>		<sourcecode type="pseudocode"><![CDATA[
	<artwork><![CDATA[
	stripe_count = number of elements in nflda_stripe_indices;		stripe_count = number of elements in nflda_stripe_indices;
	j = (SUi + nfl_first_stripe_index) % stripe_count;		j = (SUi + nfl_first_stripe_index) % stripe_count;
	idx = nflda_stripe_indices[j];		idx = nflda_stripe_indices[j];
	fh_count = number of elements in nfl_fh_list;		fh_count = number of elements in nfl_fh_list;
	ds_count = number of elements in nflda_multipath_ds_list;		ds_count = number of elements in nflda_multipath_ds_list;
	switch (fh_count) {		switch (fh_count) {
	skipping to change at line 21880 ¶		skipping to change at line 21936 ¶
	case 0:		case 0:
	fh = filehandle returned by OPEN;		fh = filehandle returned by OPEN;
	break;		break;
	default:		default:
	throw a fatal exception;		throw a fatal exception;
	break;		break;
	}		}
	address_list = nflda_multipath_ds_list[idx];		address_list = nflda_multipath_ds_list[idx];]]></sourcecode>
			<t>
	]]></artwork>
	</figure>
	<t>
	The client would then select a data server from address_list, and		The client would then select a data server from address_list, and
	send a READ or WRITE operation using the filehandle specified in fh.		send a READ or WRITE operation using the filehandle specified in fh.
	</t>		</t>
	<t>		<t>
	Consider the following example:		Consider the following example:
	</t>		</t>
	<t>		<t>
	Suppose we have a device address consisting of seven		Suppose we have a device address consisting of seven
	data servers, arranged in three equivalence (<xref		data servers, arranged in three equivalence (<xref target="file_multipath" for
	target="file_multipath" />) classes:		mat="default"/>) classes:
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	{ A, B, C, D }, { E }, { F, G }		{ A, B, C, D }, { E }, { F, G }
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	where A through G are network addresses.		where A through G are network addresses.
	</t>		</t>
	<t>		<t>
	Then		Then
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nflda_multipath_ds_list&lt;&gt; = { A, B, C, D }, { E }, { F, G }		nflda_multipath_ds_list&lt;&gt; = { A, B, C, D }, { E }, { F, G }
	</t>		</li>
	</list>		</ul>
			<t>
	i.e.,		i.e.,
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nflda_multipath_ds_list[0] = { A, B, C, D }		nflda_multipath_ds_list[0] = { A, B, C, D }
	</t>		</li>
	<t>		<li>
	nflda_multipath_ds_list[1] = { E }		nflda_multipath_ds_list[1] = { E }
	</t>		</li>
	<t>		<li>
	nflda_multipath_ds_list[2] = { F, G }		nflda_multipath_ds_list[2] = { F, G }
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Suppose the striping index array is:		Suppose the striping index array is:
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nflda_stripe_indices&lt;&gt; = { 2, 0, 1, 0 }		nflda_stripe_indices&lt;&gt; = { 2, 0, 1, 0 }
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Now suppose the client gets a layout that has a device ID		Now suppose the client gets a layout that has a device ID
	that maps to the above device address. The initial index contains		that maps to the above device address. The initial index contains
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nfl_first_stripe_index = 2,		nfl_first_stripe_index = 2,
	</t>		</li>
	</list>		</ul>
			<t>
	and the filehandle list is		and the filehandle list is
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nfl_fh_list = { 0x36, 0x87, 0x67 }.		nfl_fh_list = { 0x36, 0x87, 0x67 }.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	If the client wants to write to SU0, the		If the client wants to write to SU0, the
	set of valid { network address, filehandle } combinations		set of valid { network address, filehandle } combinations
	for SUi are determined by:		for SUi are determined by:
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nfl_first_stripe_index = 2		nfl_first_stripe_index = 2
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	So		So
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
			<t>
	idx = nflda_stripe_indices[(0 + 2) % 4]		idx = nflda_stripe_indices[(0 + 2) % 4]
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	= nflda_stripe_indices[2]		= nflda_stripe_indices[2]
	</t>		</li>
	<t>		<li>
	= 1		= 1
	</t>		</li>
	</list>		</ul>
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	So		So
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nflda_multipath_ds_list[1] = { E }		nflda_multipath_ds_list[1] = { E }
	</t>		</li>
	</list>		</ul>
			<t>
	and		and
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nfl_fh_list[1] = { 0x87 }		nfl_fh_list[1] = { 0x87 }
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The client can thus write SU0 to { 0x87, { E } }.		The client can thus write SU0 to { 0x87, { E } }.
	</t>		</t>
	<t>		<t>
	The destinations of the first 13 storage units are:		The destinations of the first 13 storage units are:
	</t>		</t>
	<texttable>		<!-- [rfced] We're curious why tables 9 and 10 contain blank lines? They don't
			appear in the original. We're trying to understand the best XML to use to
	<ttcol>SUi</ttcol> <ttcol>filehandle</ttcol> <ttcol>data servers</ttcol>		format this table, and we wonder whether the breaks are necssary.
			-->
	<c>0</c> <c> 87 </c><c> E </c>		<table align="center">
	<c>1</c><c>36</c><c>A,B,C,D</c>		<thead>
	<c>2</c><c>67</c><c>F,G</c>		<tr>
	<c>3</c><c>36 </c><c>A,B,C,D</c>		<th align="left">SUi</th>
			<th align="left">filehandle</th>
	<c/> <c/> <c/>		<th align="left">data servers</th>
			</tr>
	<c>4</c><c>87</c><c>E</c>		</thead>
	<c>5</c><c>36</c><c>A,B,C,D</c>		<tbody>
	<c>6</c><c>67</c><c>F,G</c>		<tr>
	<c>7</c><c>36</c><c>A,B,C,D</c>		<td align="left">0</td>
			<td align="left">87 </td>
	<c/> <c/> <c/>		<td align="left">E </td>
	<c>8</c><c>87</c><c>E</c>		</tr>
	<c>9</c><c>36</c><c>A,B,C,D</c>		<tr>
	<c>10</c><c>67</c><c>F,G</c>		<td align="left">1</td>
	<c>11</c><c>36</c><c>A,B,C,D</c>		<td align="left">36</td>
			<td align="left">A,B,C,D</td>
	<c/> <c/> <c/>		</tr>
			<tr>
	<c>12</c><c>87</c><c>E</c>		<td align="left">2</td>
			<td align="left">67</td>
	</texttable>		<td align="left">F,G</td>
	</section>		</tr>
	<section title="Interpreting the File Layout Using Dense Packing">		<tr>
	<t>		<td align="left">3</td>
			<td align="left">36 </td>
			<td align="left">A,B,C,D</td>
			</tr>
			<tr>
			<td align="left"/>
			<td align="left"/>
			<td align="left"/>
			</tr>
			<tr>
			<td align="left">4</td>
			<td align="left">87</td>
			<td align="left">E</td>
			</tr>
			<tr>
			<td align="left">5</td>
			<td align="left">36</td>
			<td align="left">A,B,C,D</td>
			</tr>
			<tr>
			<td align="left">6</td>
			<td align="left">67</td>
			<td align="left">F,G</td>
			</tr>
			<tr>
			<td align="left">7</td>
			<td align="left">36</td>
			<td align="left">A,B,C,D</td>
			</tr>
			<tr>
			<td align="left"/>
			<td align="left"/>
			<td align="left"/>
			</tr>
			<tr>
			<td align="left">8</td>
			<td align="left">87</td>
			<td align="left">E</td>
			</tr>
			<tr>
			<td align="left">9</td>
			<td align="left">36</td>
			<td align="left">A,B,C,D</td>
			</tr>
			<tr>
			<td align="left">10</td>
			<td align="left">67</td>
			<td align="left">F,G</td>
			</tr>
			<tr>
			<td align="left">11</td>
			<td align="left">36</td>
			<td align="left">A,B,C,D</td>
			</tr>
			<tr>
			<td align="left"/>
			<td align="left"/>
			<td align="left"/>
			</tr>
			<tr>
			<td align="left">12</td>
			<td align="left">87</td>
			<td align="left">E</td>
			</tr>
			</tbody>
			</table>
			</section>
			<section numbered="true" toc="default">
			<name>Interpreting the File Layout Using Dense Packing</name>
			<t>
	When dense packing is used, the algorithm for determining the filehandle and s et		When dense packing is used, the algorithm for determining the filehandle and s et
	of data server network addresses to write stripe unit i (SUi) to is:		of data server network addresses to write stripe unit i (SUi) to is:
	</t>		</t>
	<figure>		<sourcecode type="pseudocode"><![CDATA[
	<artwork><![CDATA[
	stripe_count = number of elements in nflda_stripe_indices;		stripe_count = number of elements in nflda_stripe_indices;
	j = (SUi + nfl_first_stripe_index) % stripe_count;		j = (SUi + nfl_first_stripe_index) % stripe_count;
	idx = nflda_stripe_indices[j];		idx = nflda_stripe_indices[j];
	fh_count = number of elements in nfl_fh_list;		fh_count = number of elements in nfl_fh_list;
	ds_count = number of elements in nflda_multipath_ds_list;		ds_count = number of elements in nflda_multipath_ds_list;
	switch (fh_count) {		switch (fh_count) {
	case stripe_count:		case stripe_count:
	fh = nfl_fh_list[j];		fh = nfl_fh_list[j];
	break;		break;
	default:		default:
	throw a fatal exception;		throw a fatal exception;
	break;		break;
	}		}
	address_list = nflda_multipath_ds_list[idx];		address_list = nflda_multipath_ds_list[idx];]]></sourcecode>
			<t>
	]]></artwork>
	</figure>
	<t>
	The client would then select a data server from address_list, and		The client would then select a data server from address_list, and
	send a READ or WRITE operation using the filehandle specified in fh.		send a READ or WRITE operation using the filehandle specified in fh.
	</t>		</t>
	<t>		<t>
	Consider the following example (which is the same		Consider the following example (which is the same
	as the sparse packing example, except for the		as the sparse packing example, except for the
	filehandle list):		filehandle list):
	</t>		</t>
	<t>		<t>
	Suppose we have a device address consisting of seven		Suppose we have a device address consisting of seven
	data servers, arranged in three equivalence (<xref		data servers, arranged in three equivalence (<xref target="file_multipath" for
	target="file_multipath" />) classes:		mat="default"/>) classes:
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	{ A, B, C, D }, { E }, { F, G }		{ A, B, C, D }, { E }, { F, G }
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	where A through G are network addresses.		where A through G are network addresses.
	</t>		</t>
	<t>		<t>
	Then		Then
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nflda_multipath_ds_list&lt;&gt; = { A, B, C, D }, { E }, { F, G }		nflda_multipath_ds_list&lt;&gt; = { A, B, C, D }, { E }, { F, G }
	</t>		</li>
	</list>		</ul>
			<t>
	i.e.,		i.e.,
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nflda_multipath_ds_list[0] = { A, B, C, D }		nflda_multipath_ds_list[0] = { A, B, C, D }
	</t>		</li>
	<t>		<li>
	nflda_multipath_ds_list[1] = { E }		nflda_multipath_ds_list[1] = { E }
	</t>		</li>
	<t>		<li>
	nflda_multipath_ds_list[2] = { F, G }		nflda_multipath_ds_list[2] = { F, G }
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Suppose the striping index array is:		Suppose the striping index array is:
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nflda_stripe_indices&lt;&gt; = { 2, 0, 1, 0 }		nflda_stripe_indices&lt;&gt; = { 2, 0, 1, 0 }
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Now suppose the client gets a layout that has a device ID		Now suppose the client gets a layout that has a device ID
	that maps to the above device address. The initial index contains		that maps to the above device address. The initial index contains
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nfl_first_stripe_index = 2,		nfl_first_stripe_index = 2,
	</t>		</li>
	</list>		</ul>
			<t>
	and		and
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nfl_fh_list = { 0x67, 0x37, 0x87, 0x36 }.		nfl_fh_list = { 0x67, 0x37, 0x87, 0x36 }.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The interesting examples for dense packing are		The interesting examples for dense packing are
	SU1 and SU3 because each stripe unit refers to the		SU1 and SU3 because each stripe unit refers to the
	same data server list, yet each stripe unit MUST use a different filehandle.		same data server list, yet each stripe unit <bcp14>MUST</bcp14> use a differen t filehandle.
	If the client wants to write to SU1, the		If the client wants to write to SU1, the
	set of valid { network address, filehandle } combinations		set of valid { network address, filehandle } combinations
	for SUi are determined by:		for SUi are determined by:
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
	nfl_first_stripe_index = 2		<li> nfl_first_stripe_index = 2 </li>
	</t>		</ul>
	</list>		<t>
	</t>
	<t>
	So		So
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
	j = (1 + 2) % 4 = 3		<li>
	<list style='empty'>		<t> j = (1 + 2) % 4 = 3 </t>
	<t>		<ul empty="true" spacing="normal">
	idx = nflda_stripe_indices[j]		<li> idx = nflda_stripe_indices[j] </li>
	</t>		<li> = nflda_stripe_indices[3] </li>
	<t>		<li> = 0 </li>
	= nflda_stripe_indices[3]		</ul>
	</t>		</li>
	<t>		</ul>
	= 0		<t>
	</t>
	</list>
	</t>
	</list>
	</t>
	<t>
	So		So
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nflda_multipath_ds_list[0] = { A, B, C, D }		nflda_multipath_ds_list[0] = { A, B, C, D }
	</t>		</li>
	</list>		</ul>
			<t>
	and		and
	<list style='empty'>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	nfl_fh_list[3] = { 0x36 }		nfl_fh_list[3] = { 0x36 }
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The client can thus write SU1 to { 0x36, { A, B, C, D } }.		The client can thus write SU1 to { 0x36, { A, B, C, D } }.
	</t>		</t>
	<t>		<t>
	For SU3, j = (3 + 2) % 4 = 1, and nflda_stripe_indices[1] = 0.		For SU3, j = (3 + 2) % 4 = 1, and nflda_stripe_indices[1] = 0.
	Then nflda_multipath_ds_list[0] = { A, B, C, D }, and		Then nflda_multipath_ds_list[0] = { A, B, C, D }, and
	nfl_fh_list[1] = 0x37. The client can thus write SU3 to		nfl_fh_list[1] = 0x37. The client can thus write SU3 to
	{ 0x37, { A, B, C, D } }.		{ 0x37, { A, B, C, D } }.
	</t>		</t>
	<t>		<t>
	The destinations of the first 13 storage units are:		The destinations of the first 13 storage units are:
	</t>		</t>
	<texttable>		<table align="center">
			<thead>
	<ttcol>SUi</ttcol> <ttcol>filehandle</ttcol> <ttcol>data servers</ttcol>		<tr>
			<th align="left">SUi</th>
	<c>0</c> <c> 87 </c><c> E </c>		<th align="left">filehandle</th>
	<c>1</c><c>36</c><c>A,B,C,D</c>		<th align="left">data servers</th>
	<c>2</c><c>67</c><c>F,G</c>		</tr>
	<c>3</c><c>37 </c><c>A,B,C,D</c>		</thead>
			<tbody>
	<c/> <c/> <c/>		<tr>
			<td align="left">0</td>
	<c>4</c><c>87</c><c>E</c>		<td align="left"> 87 </td>
	<c>5</c><c>36</c><c>A,B,C,D</c>		<td align="left"> E </td>
	<c>6</c><c>67</c><c>F,G</c>		</tr>
	<c>7</c><c>37</c><c>A,B,C,D</c>		<tr>
			<td align="left">1</td>
	<c/> <c/> <c/>		<td align="left">36</td>
	<c>8</c><c>87</c><c>E</c>		<td align="left">A,B,C,D</td>
	<c>9</c><c>36</c><c>A,B,C,D</c>		</tr>
	<c>10</c><c>67</c><c>F,G</c>		<tr>
	<c>11</c><c>37</c><c>A,B,C,D</c>		<td align="left">2</td>
			<td align="left">67</td>
	<c/> <c/> <c/>		<td align="left">F,G</td>
			</tr>
	<c>12</c><c>87</c><c>E</c>		<tr>
			<td align="left">3</td>
	</texttable>		<td align="left">37 </td>
	</section>		<td align="left">A,B,C,D</td>
			</tr>
	<section title="Sparse and Dense Stripe Unit Packing"		<tr>
	anchor="sparse_dense">		<td align="left"/>
	<t>		<td align="left"/>
			<td align="left"/>
			</tr>
			<tr>
			<td align="left">4</td>
			<td align="left">87</td>
			<td align="left">E</td>
			</tr>
			<tr>
			<td align="left">5</td>
			<td align="left">36</td>
			<td align="left">A,B,C,D</td>
			</tr>
			<tr>
			<td align="left">6</td>
			<td align="left">67</td>
			<td align="left">F,G</td>
			</tr>
			<tr>
			<td align="left">7</td>
			<td align="left">37</td>
			<td align="left">A,B,C,D</td>
			</tr>
			<tr>
			<td align="left"/>
			<td align="left"/>
			<td align="left"/>
			</tr>
			<tr>
			<td align="left">8</td>
			<td align="left">87</td>
			<td align="left">E</td>
			</tr>
			<tr>
			<td align="left">9</td>
			<td align="left">36</td>
			<td align="left">A,B,C,D</td>
			</tr>
			<tr>
			<td align="left">10</td>
			<td align="left">67</td>
			<td align="left">F,G</td>
			</tr>
			<tr>
			<td align="left">11</td>
			<td align="left">37</td>
			<td align="left">A,B,C,D</td>
			</tr>
			<tr>
			<td align="left"/>
			<td align="left"/>
			<td align="left"/>
			</tr>
			<tr>
			<td align="left">12</td>
			<td align="left">87</td>
			<td align="left">E</td>
			</tr>
			</tbody>
			</table>
			</section>
			<section anchor="sparse_dense" numbered="true" toc="default">
			<name>Sparse and Dense Stripe Unit Packing</name>
			<t>
	The flag NFL4_UFLG_DENSE of the nfl_util4 data type (field nflh_util of the		The flag NFL4_UFLG_DENSE of the nfl_util4 data type (field nflh_util of the
	data type nfsv4_1_file_layouthint4 and field nfl_util of		data type nfsv4_1_file_layouthint4 and field nfl_util of
	data type nfsv4_1_file_layout_ds_addr4) specifies how the data		data type nfsv4_1_file_layout_ds_addr4) specifies how the data
	is packed within the		is packed within the
	data file on a data server. It allows for two different data		data file on a data server. It allows for two different data
	packings: sparse and dense. The packing type determines the		packings: sparse and dense. The packing type determines the
	calculation that will be made to map the client-visible file offset		calculation that will be made to map the client-visible file offset
	to the offset within the data file located on the data server.		to the offset within the data file located on the data server.
	</t>		</t>
	<t>		<t>
	If nfl_util &amp; NFL4_UFLG_DENSE is zero, this means that		If nfl_util &amp; NFL4_UFLG_DENSE is zero, this means that
	sparse packing is being used. Hence, the logical offsets of the		sparse packing is being used. Hence, the logical offsets of the
	file as viewed by a client		file as viewed by a client
	sending READs and WRITEs directly to the metadata server		sending READs and WRITEs directly to the metadata server
	are the same offsets each data server uses when storing		are the same offsets each data server uses when storing
	a stripe unit. The effect then, for striping patterns		a stripe unit. The effect then, for striping patterns
	consisting of at least two stripe units, is for each		consisting of at least two stripe units, is for each
	data server file to be sparse or "holey". So for example,		data server file to be sparse or "holey". So for example,
	suppose there is a pattern with three stripe units, the stripe unit		suppose there is a pattern with three stripe units, the stripe unit
	size is 4096 bytes, and there are three data servers in		size is 4096 bytes, and there are three data servers in
	the pattern. Then, the file in data server 1 will have		the pattern. Then, the file in data server 1 will have
	stripe units 0, 3, 6, 9, ... filled; data server 2's		stripe units 0, 3, 6, 9, ... filled; data server 2's
	file will have stripe units 1, 4, 7, 10, ... filled;		file will have stripe units 1, 4, 7, 10, ... filled;
	and data server 3's file will have stripe units 2,		and data server 3's file will have stripe units 2,
	5, 8, 11, ... filled. The unfilled stripe units of		5, 8, 11, ... filled. The unfilled stripe units of
	each file will be holes; hence, the files in each data		each file will be holes; hence, the files in each data
	server are sparse.		server are sparse.
	</t>		</t>
	<t>		<t>
	If sparse packing is being used and a client attempts I/O to one of		If sparse packing is being used and a client attempts I/O to one of
	the holes, then an error MUST be		the holes, then an error <bcp14>MUST</bcp14> be
	returned by the data server. Using the above example, if data server 3 receiv ed a READ or WRITE operation for block 4, the data server		returned by the data server. Using the above example, if data server 3 receiv ed a READ or WRITE operation for block 4, the data server
	would return NFS4ERR_PNFS_IO_HOLE. Thus,		would return NFS4ERR_PNFS_IO_HOLE. Thus,
	data servers need to understand the striping pattern in order		data servers need to understand the striping pattern in order
	to support sparse packing.		to support sparse packing.
	</t>		</t>
	<t>		<t>
	If nfl_util &amp; NFL4_UFLG_DENSE is one, this means that		If nfl_util &amp; NFL4_UFLG_DENSE is one, this means that
	dense packing is being used, and the data server files have no holes.		dense packing is being used, and the data server files have no holes.
	Dense packing might be selected because the data server does not		Dense packing might be selected because the data server does not
	(efficiently) support holey files or because the data server		(efficiently) support holey files or because the data server
	cannot recognize read-ahead unless there are no holes.		cannot recognize read-ahead unless there are no holes.
	If dense packing is indicated in the layout,		If dense packing is indicated in the layout,
	the data files will be packed. Using the		the data files will be packed. Using the
	same striping pattern and stripe unit size that were used for		same striping pattern and stripe unit size that were used for
	the sparse packing example, the corresponding dense packing example would hav e		the sparse packing example, the corresponding dense packing example would hav e
	all stripe units of all data files filled as follows:		all stripe units of all data files filled as follows:
	<list style='symbols'>		</t>
			<ul spacing="normal">
	<t>		<li>
	Logical stripe units 0, 3, 6, ... of the file would live on		Logical stripe units 0, 3, 6, ... of the file would live on
	stripe units 0, 1, 2, ... of the file of data server 1.		stripe units 0, 1, 2, ... of the file of data server 1.
	</t>		</li>
			<li>
	<t>
	Logical stripe units 1, 4, 7, ... of the file would live on		Logical stripe units 1, 4, 7, ... of the file would live on
	stripe units 0, 1, 2, ... of the file of data server 2.		stripe units 0, 1, 2, ... of the file of data server 2.
	</t>		</li>
			<li>
	<t>
	Logical stripe units 2, 5, 8, ... of the file would live on		Logical stripe units 2, 5, 8, ... of the file would live on
	stripe units 0, 1, 2, ... of the file of data server 3.		stripe units 0, 1, 2, ... of the file of data server 3.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Because dense packing does not leave holes on the data servers,		Because dense packing does not leave holes on the data servers,
	the pNFS client is allowed to write to any offset of any data file of		the pNFS client is allowed to write to any offset of any data file of
	any data server in the stripe. Thus, the data servers need not know		any data server in the stripe. Thus, the data servers need not know
	the file's striping pattern.		the file's striping pattern.
	</t>		</t>
	<t>		<t>
	The calculation to determine the byte offset within the data file		The calculation to determine the byte offset within the data file
	for dense data server layouts is:		for dense data server layouts is:
	</t>		</t>
	<figure>		<sourcecode type="pseudocode"><![CDATA[
	<artwork><![CDATA[
	stripe_width = stripe_unit_size * N;		stripe_width = stripe_unit_size * N;
	where N = number of elements in nflda_stripe_indices.		where N = number of elements in nflda_stripe_indices.
	relative_offset = file_offset - nfl_pattern_offset;		relative_offset = file_offset - nfl_pattern_offset;
	data_file_offset = floor(relative_offset / stripe_width)		data_file_offset = floor(relative_offset / stripe_width)
	* stripe_unit_size		* stripe_unit_size
	+ relative_offset % stripe_unit_size		+ relative_offset % stripe_unit_size]]></sourcecode>
	]]></artwork>		<t>
	</figure>
	<t>
	If dense packing is being used, and a data server appears		If dense packing is being used, and a data server appears
	more than once in a striping pattern, then to distinguish		more than once in a striping pattern, then to distinguish
	one stripe unit from another, the data server MUST use a		one stripe unit from another, the data server <bcp14>MUST</bcp14> use a
	different filehandle. Let's suppose there are two data		different filehandle. Let's suppose there are two data
	servers. Logical stripe units 0, 3, 6 are served by		servers. Logical stripe units 0, 3, 6 are served by
	data server 1; logical stripe units 1, 4, 7 are served		data server 1; logical stripe units 1, 4, 7 are served
	by data server 2; and logical stripe units 2, 5, 8 are		by data server 2; and logical stripe units 2, 5, 8 are
	also served by data server 2. Unless data server 2 has		also served by data server 2. Unless data server 2 has
	two filehandles (each referring to a different data		two filehandles (each referring to a different data
	file), then, for example, a write to logical stripe		file), then, for example, a write to logical stripe
	unit 1 overwrites the write to logical stripe unit 2		unit 1 overwrites the write to logical stripe unit 2
	because both logical stripe units are located in the		because both logical stripe units are located in the
	same stripe unit (0) of data server 2.		same stripe unit (0) of data server 2.
	</t>		</t>
			</section>
	</section>		</section>
	</section> <!-- "Interpreting the File Layout" anchor="file_layout_interpret" -
	->
	<section title="Data Server Multipathing" anchor="file_multipath">		<section anchor="file_multipath" numbered="true" toc="default">
	<t>		<name>Data Server Multipathing</name>
			<t>
	The NFSv4.1 file layout supports multipathing to		The NFSv4.1 file layout supports multipathing to
	multiple data server addresses.		multiple data server addresses.
	Data-server-level multipathing is used for		Data-server-level multipathing is used for
	bandwidth scaling via trunking (<xref target="Trunking"		bandwidth scaling via trunking (<xref target="Trunking" format="default"/>) an
	/>) and for higher availability of use in the case of		d for higher availability of use in the case of
	a data-server failure. Multipathing allows the client		a data-server failure. Multipathing allows the client
	to switch to another data server address which may be that		to switch to another data server address which may be that
	of another data server that is exporting the		of another data server that is exporting the
	same data stripe unit, without having to contact the		same data stripe unit, without having to contact the
	metadata server for a new layout.		metadata server for a new layout.
	</t>		</t>
	<t>		<t>
	To support data server multipathing, each element of		To support data server multipathing, each element of
	the nflda_multipath_ds_list contains an array of one		the nflda_multipath_ds_list contains an array of one
	more data server network addresses. This array (data		more data server network addresses. This array (data
	type multipath_list4) represents a list of data servers		type multipath_list4) represents a list of data servers
	(each identified by a network address), with the possibility		(each identified by a network address), with the possibility
	that some data servers will appear in the list multiple times.		that some data servers will appear in the list multiple times.
	</t>		</t>
	<t>		<t>
	The client is free to use any of the network addresses		The client is free to use any of the network addresses
	as a destination to send data server requests. If some		as a destination to send data server requests. If some
	network addresses are less optimal paths to the data than		network addresses are less optimal paths to the data than
	others, then the MDS SHOULD NOT include those network		others, then the MDS <bcp14>SHOULD NOT</bcp14> include those network
	addresses in an element of nflda_multipath_ds_list. If		addresses in an element of nflda_multipath_ds_list. If
	less optimal network addresses exist to provide failover, the		less optimal network addresses exist to provide failover, the
	RECOMMENDED method to offer the addresses is		<bcp14>RECOMMENDED</bcp14> method to offer the addresses is
	to provide them in a replacement device-ID-to-device-address		to provide them in a replacement device-ID-to-device-address
	mapping, or a replacement device ID. When		mapping, or a replacement device ID. When
	a client finds that no data server in an element of		a client finds that no data server in an element of
	nflda_multipath_ds_list responds, it SHOULD send a		nflda_multipath_ds_list responds, it <bcp14>SHOULD</bcp14> send a
	GETDEVICEINFO to attempt to replace the existing		GETDEVICEINFO to attempt to replace the existing
	device-ID-to-device-address mappings. If the MDS detects		device-ID-to-device-address mappings. If the MDS detects
	that all data servers represented by an element of		that all data servers represented by an element of
	nflda_multipath_ds_list are unavailable, the MDS SHOULD		nflda_multipath_ds_list are unavailable, the MDS <bcp14>SHOULD</bcp14>
	send a CB_NOTIFY_DEVICEID (if the client has indicated		send a CB_NOTIFY_DEVICEID (if the client has indicated
	it wants device ID notifications for changed device IDs)		it wants device ID notifications for changed device IDs)
	to change the device-ID-to-device-address mappings to		to change the device-ID-to-device-address mappings to
	the available data servers. If the device ID itself will		the available data servers. If the device ID itself will
	be replaced, the MDS SHOULD recall all layouts with the		be replaced, the MDS <bcp14>SHOULD</bcp14> recall all layouts with the
	device ID, and thus force the client to get new layouts		device ID, and thus force the client to get new layouts
	and device ID mappings via LAYOUTGET and GETDEVICEINFO.		and device ID mappings via LAYOUTGET and GETDEVICEINFO.
	</t>		</t>
	<t>		<t>
	Generally, if two network addresses appear in an element		Generally, if two network addresses appear in an element
	of nflda_multipath_ds_list, they will designate the same		of nflda_multipath_ds_list, they will designate the same
	data server, and the two data server addresses will		data server, and the two data server addresses will
	support the implementation of		support the implementation of
	client ID or session trunking (the latter is RECOMMENDED)		client ID or session trunking (the latter is <bcp14>RECOMMENDED</bcp14>)
	as defined in <xref target="Trunking"/>. The two		as defined in <xref target="Trunking" format="default"/>. The two
	data server addresses will share the same server owner		data server addresses will share the same server owner
	or major ID of the server owner. It is not always necessary for the		or major ID of the server owner. It is not always necessary for the
	two data server addresses to designate the same server		two data server addresses to designate the same server
	with trunking being used. For example,		with trunking being used. For example,
	the data could be read-only, and the data consist of		the data could be read-only, and the data consist of
	exact replicas.		exact replicas.
	</t>		</t>
	</section>		</section>
			<section anchor="ds_ops" numbered="true" toc="default">
	<section title="Operations Sent to NFSv4.1 Data Servers" anchor="ds_ops">		<name>Operations Sent to NFSv4.1 Data Servers</name>
	<t>		<t>
	Clients accessing data on an NFSv4.1 data server MUST send		Clients accessing data on an NFSv4.1 data server <bcp14>MUST</bcp14> send
	only the NULL procedure and COMPOUND procedures whose		only the NULL procedure and COMPOUND procedures whose
	operations are taken only from two restricted		operations are taken only from two restricted
	subsets of the operations defined as valid NFSv4.1		subsets of the operations defined as valid NFSv4.1
	operations. Clients MUST use the filehandle specified		operations. Clients <bcp14>MUST</bcp14> use the filehandle specified
	by the layout when accessing data on NFSv4.1 data		by the layout when accessing data on NFSv4.1 data
	servers.		servers.
	</t>		</t>
	<t>		<t>
	The first of these operation subsets consists of management operations.		The first of these operation subsets consists of management operations.
	This subset consists of the BACKCHANNEL_CTL, BIND_CONN_TO_SESSION, CREATE_SESS ION,		This subset consists of the BACKCHANNEL_CTL, BIND_CONN_TO_SESSION, CREATE_SESS ION,
	DESTROY_CLIENTID, DESTROY_SESSION, EXCHANGE_ID,		DESTROY_CLIENTID, DESTROY_SESSION, EXCHANGE_ID,
	SECINFO_NO_NAME, SET_SSV, and SEQUENCE operations.		SECINFO_NO_NAME, SET_SSV, and SEQUENCE operations.
	The client may use these operations in order to set		The client may use these operations in order to set
	up and maintain the appropriate client IDs,		up and maintain the appropriate client IDs,
	sessions, and security contexts involved in communication with the data		sessions, and security contexts involved in communication with the data
	server. Henceforth, these will be referred to as		server. Henceforth, these will be referred to as
	data-server housekeeping operations.		data-server housekeeping operations.
	</t>		</t>
	<t>		<t>
	The second subset consists of COMMIT, READ, WRITE, and PUTFH.		The second subset consists of COMMIT, READ, WRITE, and PUTFH.
	These operations MUST be used with a current filehandle specified by the		These operations <bcp14>MUST</bcp14> be used with a current filehandle specifi
	layout. In the case of PUTFH, the new current filehandle MUST be		ed by the
			layout. In the case of PUTFH, the new current filehandle <bcp14>MUST</bcp14>
			be
	one taken from the layout. Henceforth, these will be referred to as data-serve r		one taken from the layout. Henceforth, these will be referred to as data-serve r
	I/O operations. As described in <xref target="layout_semantics" />,		I/O operations. As described in <xref target="layout_semantics" format="defau
	a client MUST NOT send an I/O to a data server for which it does not hold a		lt"/>,
	valid layout; the data server MUST reject such an I/O.		a client <bcp14>MUST NOT</bcp14> send an I/O to a data server for which it doe
	</t>		s not hold a
	<t>		valid layout; the data server <bcp14>MUST</bcp14> reject such an I/O.
			</t>
			<t>
	Unless the server has a concurrent non-data-server		Unless the server has a concurrent non-data-server
	personality -- i.e., EXCHANGE_ID results returned		personality -- i.e., EXCHANGE_ID results returned
	(EXCHGID4_FLAG_USE_PNFS_DS | EXCHGID4_FLAG_USE_PNFS_MDS)		(EXCHGID4_FLAG_USE_PNFS_DS | EXCHGID4_FLAG_USE_PNFS_MDS)
	or (EXCHGID4_FLAG_USE_PNFS_DS | EXCHGID4_FLAG_USE_NON_PNFS) see		or (EXCHGID4_FLAG_USE_PNFS_DS | EXCHGID4_FLAG_USE_NON_PNFS) see
	<xref target="pnfs_session_stuff"/> -- any attempted use of		<xref target="pnfs_session_stuff" format="default"/> -- any attempted use of
	operations against a data server other than those specified in the two		operations against a data server other than those specified in the two
	subsets above MUST return		subsets above <bcp14>MUST</bcp14> return
	NFS4ERR_NOTSUPP to the client.		NFS4ERR_NOTSUPP to the client.
	</t>		</t>
	<t>		<t>
	When the server has concurrent data-server and		When the server has concurrent data-server and
	non-data-server personalities, each COMPOUND sent by the		non-data-server personalities, each COMPOUND sent by the
	client MUST be constructed		client <bcp14>MUST</bcp14> be constructed
	so that it is appropriate to one of the two personalities, and it		so that it is appropriate to one of the two personalities, and it
	MUST NOT contain operations directed to a mix of those		<bcp14>MUST NOT</bcp14> contain operations directed to a mix of those
	personalities. The server MUST enforce this. To understand		personalities. The server <bcp14>MUST</bcp14> enforce this. To understand
	the constraints, operations within a COMPOUND are divided into		the constraints, operations within a COMPOUND are divided into
	the following three classes:		the following three classes:
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	An operation that is ambiguous regarding its personality		An operation that is ambiguous regarding its personality
	assignment. This includes all of the data-server		assignment. This includes all of the data-server
	housekeeping operations. Additionally, if the		housekeeping operations. Additionally, if the
	server has assigned filehandles so that the ones defined		server has assigned filehandles so that the ones defined
	by the layout are the same as those used by the metadata		by the layout are the same as those used by the metadata
	server, all operations using such filehandles are within this		server, all operations using such filehandles are within this
	class, with the following exception. The exception is		class, with the following exception. The exception is
	that if the operation uses a stateid that is incompatible with a		that if the operation uses a stateid that is incompatible with a
	data-server personality (e.g., a special stateid or the		data-server personality (e.g., a special stateid or the
	stateid has a non-zero "seqid" field, see		stateid has a non-zero "seqid" field, see
	<xref target="global_stateid"/>), the operation is in class 3,		<xref target="global_stateid" format="default"/>), the operation is in cla ss 3,
	as described below. A COMPOUND containing		as described below. A COMPOUND containing
	multiple class 1 operations (and operations of no other		multiple class 1 operations (and operations of no other
	class) MAY be sent to a server with multiple concurrent data server		class) <bcp14>MAY</bcp14> be sent to a server with multiple concurrent dat a server
	and non-data-server personalities.		and non-data-server personalities.
	</t>		</li>
	<t>		<li>
	An operation that is unambiguously referable to the data-server		An operation that is unambiguously referable to the data-server
	personality. This includes data-server I/O operations where the		personality. This includes data-server I/O operations where the
	filehandle is one that can only be validly directed to the		filehandle is one that can only be validly directed to the
	data-server personality.		data-server personality.
	</t>		</li>
	<t>		<li>
	An operation that is unambiguously referable to the non-data-server		An operation that is unambiguously referable to the non-data-server
	personality. This includes all COMPOUND operations that are		personality. This includes all COMPOUND operations that are
	neither data-server housekeeping nor data-server I/O		neither data-server housekeeping nor data-server I/O
	operations, plus data-server I/O operations where the		operations, plus data-server I/O operations where the
	current fh (or the one to be made the current fh in the		current fh (or the one to be made the current fh in the
	case of PUTFH) is only valid on the metadata		case of PUTFH) is only valid on the metadata
	server or where a stateid is used that is incompatible		server or where a stateid is used that is incompatible
	with the data server, i.e., is a special stateid or has		with the data server, i.e., is a special stateid or has
	a non-zero seqid value.		a non-zero seqid value.
	</t>		</li>
	</list>		</ol>
	</t>		<t>
	<t>
	When a COMPOUND first executes an operation from class 3 above,		When a COMPOUND first executes an operation from class 3 above,
	it acts as a normal COMPOUND on any other server, and the		it acts as a normal COMPOUND on any other server, and the
	data-server personality ceases to be relevant.		data-server personality ceases to be relevant.
	There are no special restrictions on the		There are no special restrictions on the
	operations in the COMPOUND to limit them to those for		operations in the COMPOUND to limit them to those for
	a data server. When a PUTFH is done, filehandles		a data server. When a PUTFH is done, filehandles
	derived from the layout are not valid. If their format		derived from the layout are not valid. If their format
	is not normally acceptable, then NFS4ERR_BADHANDLE MUST		is not normally acceptable, then NFS4ERR_BADHANDLE <bcp14>MUST</bcp14>
	result. Similarly, current filehandles for other operations		result. Similarly, current filehandles for other operations
	do not accept filehandles derived from layouts and are not		do not accept filehandles derived from layouts and are not
	normally usable on the metadata server. Using these		normally usable on the metadata server. Using these
	will result in NFS4ERR_STALE.		will result in NFS4ERR_STALE.
	</t>		</t>
	<t>		<t>
	When a COMPOUND first executes an operation from class 2,		When a COMPOUND first executes an operation from class 2,
	which would be PUTFH where the filehandle		which would be PUTFH where the filehandle
	is one from a layout, the COMPOUND henceforth is interpreted		is one from a layout, the COMPOUND henceforth is interpreted
	with respect to the data-server personality.		with respect to the data-server personality.
	Operations outside the two classes discussed		Operations outside the two classes discussed
	above MUST result in NFS4ERR_NOTSUPP. Filehandles		above <bcp14>MUST</bcp14> result in NFS4ERR_NOTSUPP. Filehandles
	are validated using the rules of the data server,		are validated using the rules of the data server,
	resulting in NFS4ERR_BADHANDLE and/or NFS4ERR_STALE		resulting in NFS4ERR_BADHANDLE and/or NFS4ERR_STALE
	even when they would not normally do so when addressed		even when they would not normally do so when addressed
	to the non-data-server personality. Stateids must obey		to the non-data-server personality. Stateids must obey
	the rules of the data server in that any use of special		the rules of the data server in that any use of special
	stateids or stateids with non-zero seqid values must		stateids or stateids with non-zero seqid values must
	result in NFS4ERR_BAD_STATEID.		result in NFS4ERR_BAD_STATEID.
	</t>		</t>
	<t>		<t>
	Until the server first executes an operation from class 2		Until the server first executes an operation from class 2
	or class 3, the client MUST NOT depend on the operation		or class 3, the client <bcp14>MUST NOT</bcp14> depend on the operation
	being executed by either the data-server or the non-data-server		being executed by either the data-server or the non-data-server
	personality. The server MUST pick one personality consistently		personality. The server <bcp14>MUST</bcp14> pick one personality consistently
	for a given COMPOUND, with the only possible transition being		for a given COMPOUND, with the only possible transition being
	a single one when the first operation from class 2 or class 3		a single one when the first operation from class 2 or class 3
	is executed.		is executed.
	</t>		</t>
	<t>		<t>
	Because of the complexity induced by assigning filehandles so		Because of the complexity induced by assigning filehandles so
	they can be used on both a data server and a metadata server, it		they can be used on both a data server and a metadata server, it
	is RECOMMENDED that where the same server can have both		is <bcp14>RECOMMENDED</bcp14> that where the same server can have both
	personalities, the server assign separate unique filehandles		personalities, the server assign separate unique filehandles
	to both personalities. This makes it unambiguous for which server		to both personalities. This makes it unambiguous for which server
	a given request is intended.		a given request is intended.
	</t>		</t>
	<t>		<t>
	GETATTR and SETATTR MUST be directed to the metadata		GETATTR and SETATTR <bcp14>MUST</bcp14> be directed to the metadata
	server. In the case of a SETATTR of the size attribute,		server. In the case of a SETATTR of the size attribute,
	the control protocol is responsible for propagating size		the control protocol is responsible for propagating size
	updates/truncations to the data servers. In the case of		updates/truncations to the data servers. In the case of
	extending WRITEs to the data servers, the new size must		extending WRITEs to the data servers, the new size must
	be visible on the metadata server once a LAYOUTCOMMIT		be visible on the metadata server once a LAYOUTCOMMIT
	has completed (see <xref target="general_layoutcommit"		has completed (see <xref target="general_layoutcommit" format="default"/>). <x
	/>). <xref target="component_file_size" /> describes the		ref target="component_file_size" format="default"/> describes the
	mechanism by which the client is to handle data-server		mechanism by which the client is to handle data-server
	files that do not reflect the metadata server's size.		files that do not reflect the metadata server's size.
	</t>		</t>
	</section>		</section>
			<section anchor="commit_thru_mds" numbered="true" toc="default">
	<section title="COMMIT through Metadata Server" anchor="commit_thru_mds">		<name>COMMIT through Metadata Server</name>
	<t>		<t>
	The file layout provides two alternate means of providing for the		The file layout provides two alternate means of providing for the
	commit of data written through data servers. The flag		commit of data written through data servers. The flag
	NFL4_UFLG_COMMIT_THRU_MDS in the field nfl_util of the file layout		NFL4_UFLG_COMMIT_THRU_MDS in the field nfl_util of the file layout
	(data type nfsv4_1_file_layout4)		(data type nfsv4_1_file_layout4)
	is an indication		is an indication
	from the metadata server to the client of the REQUIRED way of		from the metadata server to the client of the <bcp14>REQUIRED</bcp14> way of
	performing COMMIT, either by sending the COMMIT to the data server		performing COMMIT, either by sending the COMMIT to the data server
	or the metadata server. These two methods of dealing with the issue		or the metadata server. These two methods of dealing with the issue
	correspond to broad styles of implementation for a pNFS server		correspond to broad styles of implementation for a pNFS server
	supporting the file layout type.		supporting the file layout type.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	When the flag is FALSE, COMMIT operations MUST to be sent		<li>
			When the flag is FALSE, COMMIT operations <bcp14>MUST</bcp14> to be sent
	to the data server to which the corresponding WRITE operations were		to the data server to which the corresponding WRITE operations were
	sent. This approach		sent. This approach
	is sometimes useful when file striping is implemented within the		is sometimes useful when file striping is implemented within the
	pNFS server (instead of the file system),		pNFS server (instead of the file system),
	with the individual data servers each implementing		with the individual data servers each implementing
	their own file systems.		their own file systems.
	</t>		</li>
	<t>		<li>
	When the flag is TRUE, COMMIT operations MUST be sent to the		<t>
			When the flag is TRUE, COMMIT operations <bcp14>MUST</bcp14> be sent to t
			he
	metadata server, rather than to the individual data servers.		metadata server, rather than to the individual data servers.
	This approach is sometimes useful when file striping		This approach is sometimes useful when file striping
	is implemented within the clustered file system that is the backend		is implemented within the clustered file system that is the backend
	to the pNFS server. In such		to the pNFS server. In such
	an implementation, each COMMIT to each		an implementation, each COMMIT to each
	data server might result in repeated writes of metadata		data server might result in repeated writes of metadata
	blocks to the		blocks to the
	detriment of write performance. Sending a single COMMIT		detriment of write performance. Sending a single COMMIT
	to the metadata server can be more efficient		to the metadata server can be more efficient
	when there exists a clustered file		when there exists a clustered file
	system capable of implementing such a coordinated COMMIT.		system capable of implementing such a coordinated COMMIT.
	<vspace blankLines='1' />		</t>
			<t>
	If nfl_util &amp; NFL4_UFLG_COMMIT_THRU_MDS is TRUE,		If nfl_util &amp; NFL4_UFLG_COMMIT_THRU_MDS is TRUE,
	then in order to maintain the current NFSv4.1 commit and		then in order to maintain the current NFSv4.1 commit and
	recovery model, the data servers MUST return a common		recovery model, the data servers <bcp14>MUST</bcp14> return a common
	writeverf verifier in all WRITE responses for a given file		writeverf verifier in all WRITE responses for a given file
	layout, and the metadata server's COMMIT implementation		layout, and the metadata server's COMMIT implementation
	must return the same writeverf. The value of the		must return the same writeverf. The value of the
	writeverf verifier MUST be changed at the metadata server		writeverf verifier <bcp14>MUST</bcp14> be changed at the metadata server
	or any data server that is referenced in the layout,		or any data server that is referenced in the layout,
	whenever there is a server event that can possibly lead to		whenever there is a server event that can possibly lead to
	loss of uncommitted data. The scope of the verifier can		loss of uncommitted data. The scope of the verifier can
	be for a file or for the entire pNFS server. It might be		be for a file or for the entire pNFS server. It might be
	more difficult for the server to maintain the verifier		more difficult for the server to maintain the verifier
	at the file level, but the benefit is that only events		at the file level, but the benefit is that only events
	that impact a given file will require recovery action.		that impact a given file will require recovery action.
	</t>		</t>
	</list>		</li>
	</t>		</ul>
	<t>		<t>
	Note that if the layout specified dense packing, then the		Note that if the layout specified dense packing, then the
	offset used to a COMMIT to the MDS may differ than that of		offset used to a COMMIT to the MDS may differ than that of
	an offset used to a COMMIT to the data server.		an offset used to a COMMIT to the data server.
	</t>		</t>
	<t>		<t>
	The single COMMIT to the metadata server will return a verifier, and		The single COMMIT to the metadata server will return a verifier, and
	the client should compare it to all the verifiers from the WRITEs and		the client should compare it to all the verifiers from the WRITEs and
	fail the COMMIT if there are any mismatched verifiers. If COMMIT to the		fail the COMMIT if there are any mismatched verifiers. If COMMIT to the
	metadata server fails, the client should re-send WRITEs for all the		metadata server fails, the client should re-send WRITEs for all the
	modified data in the file. The client should treat modified data with		modified data in the file. The client should treat modified data with
	a mismatched verifier		a mismatched verifier
	as a WRITE failure and try to recover by resending the WRITEs to the		as a WRITE failure and try to recover by resending the WRITEs to the
	original data server or using another path to that data if the layout		original data server or using another path to that data if the layout
	has not been recalled. Alternatively, the client can obtain		has not been recalled. Alternatively, the client can obtain
	a new layout or it could rewrite the data directly to the metadata server. If		a new layout or it could rewrite the data directly to the metadata server. If
	nfl_util &amp; NFL4_UFLG_COMMIT_THRU_MDS is FALSE, sending		nfl_util &amp; NFL4_UFLG_COMMIT_THRU_MDS is FALSE, sending
	a COMMIT to the metadata server might have no effect. If		a COMMIT to the metadata server might have no effect. If
	nfl_util &amp; NFL4_UFLG_COMMIT_THRU_MDS is FALSE, a COMMIT		nfl_util &amp; NFL4_UFLG_COMMIT_THRU_MDS is FALSE, a COMMIT
	sent to the metadata server should be used only to commit data that		sent to the metadata server should be used only to commit data that
	was written to the metadata server. See <xref target="storage_device_recovery" />		was written to the metadata server. See <xref target="storage_device_recovery" format="default"/>
	for recovery options.		for recovery options.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="The Layout Iomode">		<name>The Layout Iomode</name>
	<t>		<t>
	The layout iomode need not be used by the metadata server when		The layout iomode need not be used by the metadata server when
	servicing NFSv4.1 file-based layouts, although in some circumstances		servicing NFSv4.1 file-based layouts, although in some circumstances
	it may be useful. For example, if the server implementation		it may be useful. For example, if the server implementation
	supports reading from read-only replicas or mirrors, it would be		supports reading from read-only replicas or mirrors, it would be
	useful for the server to return a layout enabling the client to do		useful for the server to return a layout enabling the client to do
	so. As such, the client SHOULD set the iomode based on its intent		so. As such, the client <bcp14>SHOULD</bcp14> set the iomode based on its int ent
	to read or write the data. The client may default to an iomode of		to read or write the data. The client may default to an iomode of
	LAYOUTIOMODE4_RW. The iomode need not be checked by the		LAYOUTIOMODE4_RW. The iomode need not be checked by the
	data servers when clients perform I/O. However, the data servers		data servers when clients perform I/O. However, the data servers
	SHOULD still validate that the client holds a valid layout		<bcp14>SHOULD</bcp14> still validate that the client holds a valid layout
	and return an error if the client does not.		and return an error if the client does not.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="Metadata and Data Server State Coordination">		<name>Metadata and Data Server State Coordination</name>
			<section anchor="global_stateid" numbered="true" toc="default">
	<section title="Global Stateid Requirements" anchor="global_stateid">		<name>Global Stateid Requirements</name>
	<t>		<t>
	When the client sends		When the client sends
	I/O to a data server, the stateid used MUST NOT be a layout stateid		I/O to a data server, the stateid used <bcp14>MUST NOT</bcp14> be a layout sta teid
	as returned by LAYOUTGET or sent by CB_LAYOUTRECALL.		as returned by LAYOUTGET or sent by CB_LAYOUTRECALL.
	Permitted stateids are based on one of the following:		Permitted stateids are based on one of the following:
	an OPEN stateid		an OPEN stateid
	(the stateid field of data type OPEN4resok as returned by OPEN),		(the stateid field of data type OPEN4resok as returned by OPEN),
	a delegation stateid (the stateid field of data types open_read_delegation4		a delegation stateid (the stateid field of data types open_read_delegation4
	and open_write_delegation4 as returned by OPEN or WANT_DELEGATION,		and open_write_delegation4 as returned by OPEN or WANT_DELEGATION,
	or as sent by CB_PUSH_DELEG), or a stateid returned by the LOCK or LOCKU		or as sent by CB_PUSH_DELEG), or a stateid returned by the LOCK or LOCKU
	operations. The stateid sent to the data server MUST be sent with		operations. The stateid sent to the data server <bcp14>MUST</bcp14> be sent w ith
	the seqid set to zero, indicating the most current version of that		the seqid set to zero, indicating the most current version of that
	stateid, rather than indicating a specific non-zero seqid value. In		stateid, rather than indicating a specific non-zero seqid value. In
	no case is the use of special stateid values allowed.		no case is the use of special stateid values allowed.
	</t>		</t>
	<t>		<t>
	The stateid used for I/O MUST have the same		The stateid used for I/O <bcp14>MUST</bcp14> have the same
	effect and be subject to the same validation on a data server as it		effect and be subject to the same validation on a data server as it
	would if the I/O was being performed on the metadata server itself		would if the I/O was being performed on the metadata server itself
	in the absence of pNFS. This has the implication that stateids are		in the absence of pNFS. This has the implication that stateids are
	globally valid on both the metadata and data servers. This		globally valid on both the metadata and data servers. This
	requires the metadata server to propagate changes in LOCK and OPEN		requires the metadata server to propagate changes in LOCK and OPEN
	state to the data servers, so that the data servers can		state to the data servers, so that the data servers can
	validate I/O accesses. This is discussed further in <xref		validate I/O accesses. This is discussed further in <xref target="state_propag
	target="state_propagation" />. Depending on when stateids are		ation" format="default"/>. Depending on when stateids are
	propagated, the existence of a valid stateid on the data server		propagated, the existence of a valid stateid on the data server
	may act as proof of a valid layout.		may act as proof of a valid layout.
	</t>		</t>
	<t>		<t>
	Clients performing I/O operations need to select an appropriate		Clients performing I/O operations need to select an appropriate
	stateid based on the		stateid based on the
	locks (including opens and delegations) held by the client and		locks (including opens and delegations) held by the client and
	the various types of state-owners sending the I/O requests. The		the various types of state-owners sending the I/O requests. The
	rules for doing so when referencing data servers are somewhat		rules for doing so when referencing data servers are somewhat
	different from those discussed in <xref target="stateid_use" />,		different from those discussed in <xref target="stateid_use" format="d efault"/>,
	which apply when accessing metadata servers.		which apply when accessing metadata servers.
	</t>		</t>
	<t>		<t>
	The following rules, applied in order of decreasing priority, govern		The following rules, applied in order of decreasing priority, govern
	the selection of the appropriate stateid:		the selection of the appropriate stateid:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	If the client holds a delegation for the file in question, the		If the client holds a delegation for the file in question, the
	delegation stateid should be used.		delegation stateid should be used.
	</t>		</li>
	<t>		<li>
	Otherwise, there must be an OPEN stateid for the current		Otherwise, there must be an OPEN stateid for the current
	open-owner, and that		open-owner, and that
	OPEN stateid for the open file in question is used, unless		OPEN stateid for the open file in question is used, unless
	mandatory locking prevents that. See below.		mandatory locking prevents that. See below.
	</t>		</li>
	<t>		<li>
	If the data server had previously responded with NFS4ERR_LOCKED		If the data server had previously responded with NFS4ERR_LOCKED
	to use of the OPEN stateid, then the client should use the		to use of the OPEN stateid, then the client should use the
	byte-range lock stateid whenever one exists for that open file		byte-range lock stateid whenever one exists for that open file
	with the current lock-owner.		with the current lock-owner.
	</t>		</li>
	<t>		<li>
	Special stateids should never be used. If they are used, the data		Special stateids should never be used. If they are used, the data
	server MUST reject the I/O with an NFS4ERR_BAD_STATEID error.		server <bcp14>MUST</bcp14> reject the I/O with an NFS4ERR_BAD_STAT
	</t>		EID error.
	</list>		</li>
	</t>		</ul>
	</section>		</section>
			<section anchor="state_propagation" numbered="true" toc="default">
	<section title="Data Server State Propagation" anchor="state_propagation" >		<name>Data Server State Propagation</name>
	<t>		<t>
	Since the metadata server, which handles byte-range lock and		Since the metadata server, which handles byte-range lock and
	open-mode state changes as well as ACLs, might not be		open-mode state changes as well as ACLs, might not be
	co-located with the data servers where I/O accesses		co-located with the data servers where I/O accesses
	are validated, the server implementation MUST take		are validated, the server implementation <bcp14>MUST</bcp14> take
	care of propagating changes of this state to the data		care of propagating changes of this state to the data
	servers. Once the propagation to the data servers is		servers. Once the propagation to the data servers is
	complete, the full effect of those changes MUST be in		complete, the full effect of those changes <bcp14>MUST</bcp14> be in
	effect at the data servers. However, some state changes		effect at the data servers. However, some state changes
	need not be propagated immediately, although all changes		need not be propagated immediately, although all changes
	SHOULD be propagated promptly. These state propagations		<bcp14>SHOULD</bcp14> be propagated promptly. These state propagations
	have an impact on the design of the control protocol,		have an impact on the design of the control protocol,
	even though the control protocol is outside of the scope		even though the control protocol is outside of the scope
	of this specification. Immediate propagation refers to		of this specification. Immediate propagation refers to
	the synchronous propagation of state from the metadata		the synchronous propagation of state from the metadata
	server to the data server(s); the propagation must be		server to the data server(s); the propagation must be
	complete before returning to the client.		complete before returning to the client.
	</t>		</t>
			<section numbered="true" toc="default">
	<section title="Lock State Propagation">		<name>Lock State Propagation</name>
	<t>		<t>
	If the pNFS server supports mandatory byte-range locking, any mandatory byte-r ange locks		If the pNFS server supports mandatory byte-range locking, any mandatory byte-r ange locks
	on a file MUST be made effective at the data servers before		on a file <bcp14>MUST</bcp14> be made effective at the data servers before
	the request that establishes them returns to the caller. The		the request that establishes them returns to the caller. The
	effect MUST be the same as if the mandatory byte-range lock state were		effect <bcp14>MUST</bcp14> be the same as if the mandatory byte-range lock sta te were
	synchronously propagated to the data servers, even though the		synchronously propagated to the data servers, even though the
	details of the control protocol may avoid actual transfer of the		details of the control protocol may avoid actual transfer of the
	state under certain circumstances.		state under certain circumstances.
	</t>		</t>
	<t>		<t>
	On the other hand, since		On the other hand, since
	advisory byte-range lock state is not used for checking I/O accesses at		advisory byte-range lock state is not used for checking I/O accesses at
	the data servers, there is no semantic reason for propagating		the data servers, there is no semantic reason for propagating
	advisory byte-range lock state to the data servers.		advisory byte-range lock state to the data servers.
	Since updates to advisory locks neither confer nor remove		Since updates to advisory locks neither confer nor remove
	privileges, these changes need not be propagated immediately, and		privileges, these changes need not be propagated immediately, and
	may not need to be propagated promptly. The updates to advisory		may not need to be propagated promptly. The updates to advisory
	locks need only be propagated when the data server needs to		locks need only be propagated when the data server needs to
	resolve a question about a stateid. In fact, if byte-range locking		resolve a question about a stateid. In fact, if byte-range locking
	is not mandatory (i.e., is advisory) the clients are advised to avoid		is not mandatory (i.e., is advisory) the clients are advised to avoid
	using the byte-range lock-based stateids for I/O. The stateids returned by		using the byte-range lock-based stateids for I/O. The stateids returned by
	OPEN are sufficient and eliminate overhead for this kind of state		OPEN are sufficient and eliminate overhead for this kind of state
	propagation.		propagation.
	</t>		</t>
	<t>		<t>
	If a client gets back an NFS4ERR_LOCKED error from a		If a client gets back an NFS4ERR_LOCKED error from a
	data server, this is an indication that mandatory byte-range		data server, this is an indication that mandatory byte-range
	locking is in force. The client recovers from this by		locking is in force. The client recovers from this by
	getting a byte-range lock that covers the affected range		getting a byte-range lock that covers the affected range
	and re-sends the I/O with the stateid of the byte-range lock.		and re-sends the I/O with the stateid of the byte-range lock.
	</t>		</t>
			</section>
	</section>		<section numbered="true" toc="default">
			<name>Open and Deny Mode Validation</name>
	<section title="Open and Deny Mode Validation">		<t>
	<t>		Open and deny mode validation <bcp14>MUST</bcp14> be performed against
	Open and deny mode validation MUST be performed against
	the open and deny mode(s) held by the data servers. When		the open and deny mode(s) held by the data servers. When
	access is reduced or a deny mode made more restrictive		access is reduced or a deny mode made more restrictive
	(because of CLOSE or OPEN_DOWNGRADE), the data server MUST		(because of CLOSE or OPEN_DOWNGRADE), the data server <bcp14>MUST</bcp14>
	prevent any I/Os that would be denied if performed on the		prevent any I/Os that would be denied if performed on the
	metadata server. When access is expanded,		metadata server. When access is expanded,
	the data server MUST make sure that no requests are		the data server <bcp14>MUST</bcp14> make sure that no requests are
	subsequently rejected because of		subsequently rejected because of
	open or deny issues that no longer apply, given the		open or deny issues that no longer apply, given the
	previous relaxation.		previous relaxation.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="File Attributes">		<name>File Attributes</name>
	<t>		<t>
	Since the SETATTR operation has the ability to modify state that is		Since the SETATTR operation has the ability to modify state that is
	visible on both the metadata and data servers (e.g., the size),		visible on both the metadata and data servers (e.g., the size),
	care must be taken to ensure that the resultant state across the		care must be taken to ensure that the resultant state across the
	set of data servers is consistent, especially when truncating or		set of data servers is consistent, especially when truncating or
	growing the file.		growing the file.
	</t>		</t>
	<t>		<t>
	As described earlier, the LAYOUTCOMMIT operation is used to ensure		As described earlier, the LAYOUTCOMMIT operation is used to ensure
	that the metadata is synchronized with changes made to the data servers. For t		that the metadata is synchronized with changes made to the data servers.
	he NFSv4.1-based data storage protocol,		For the NFSv4.1-based data storage protocol,
	it is necessary to re-synchronize		it is necessary to re-synchronize
	state such as the size attribute, and the setting of mtime/change/atime.		state such as the size attribute, and the setting of mtime/change/atime.
	See <xref target="committing_layout" /> for a full		See <xref target="committing_layout" format="default"/> for a full
	description of the semantics regarding LAYOUTCOMMIT and		description of the semantics regarding LAYOUTCOMMIT and
	attribute synchronization. It should be noted that by		attribute synchronization. It should be noted that by
	using an NFSv4.1-based layout type, it is possible to		using an NFSv4.1-based layout type, it is possible to
	synchronize this state before LAYOUTCOMMIT occurs. For		synchronize this state before LAYOUTCOMMIT occurs. For
	example, the control protocol can be used to query the		example, the control protocol can be used to query the
	attributes present on the data servers.		attributes present on the data servers.
	</t>		</t>
	<t>		<t>
	Any changes to file attributes that control authorization or		Any changes to file attributes that control authorization or
	access as reflected by ACCESS calls or READs and WRITEs on the		access as reflected by ACCESS calls or READs and WRITEs on the
	metadata server, MUST be propagated to the data servers for		metadata server, <bcp14>MUST</bcp14> be propagated to the data servers for
	enforcement on READ and WRITE I/O calls. If the changes made on the		enforcement on READ and WRITE I/O calls. If the changes made on the
	metadata server result in more restrictive access permissions for		metadata server result in more restrictive access permissions for
	any user, those changes MUST be propagated to the data servers		any user, those changes <bcp14>MUST</bcp14> be propagated to the data servers
	synchronously.		synchronously.
	</t>		</t>
	<t>		<t>
	The OPEN operation (<xref target="OP_OPEN_IMPLEMENTATION"		The OPEN operation (<xref target="OP_OPEN_IMPLEMENTATION" format="default"/>)
	/>) does not impose any requirement that I/O operations		does not impose any requirement that I/O operations
	on an open file have the same credentials as the OPEN		on an open file have the same credentials as the OPEN
	itself (unless EXCHGID4_FLAG_BIND_PRINC_STATEID is		itself (unless EXCHGID4_FLAG_BIND_PRINC_STATEID is
	set when EXCHANGE_ID creates the client ID), and so it		set when EXCHANGE_ID creates the client ID), and so it
	requires the server's READ and WRITE operations to		requires the server's READ and WRITE operations to
	perform appropriate access checking. Changes to ACLs		perform appropriate access checking. Changes to ACLs
	also require new access checking by READ and WRITE on		also require new access checking by READ and WRITE on
	the server. The propagation of access-right changes due		the server. The propagation of access-right changes due
	to changes in ACLs may be asynchronous only if the server		to changes in ACLs may be asynchronous only if the server
	implementation is able to determine that the updated		implementation is able to determine that the updated
	ACL is not more restrictive for any user specified in		ACL is not more restrictive for any user specified in
	the old ACL. Due to the relative infrequency of ACL		the old ACL. Due to the relative infrequency of ACL
	updates, it is suggested that all changes be propagated		updates, it is suggested that all changes be propagated
	synchronously.		synchronously.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	</section>		</section>
			<section anchor="component_file_size" numbered="true" toc="default">
	<section title="Data Server Component File Size"		<name>Data Server Component File Size</name>
	anchor="component_file_size">		<t>
	<t>
	A potential problem exists when a component data file on a		A potential problem exists when a component data file on a
	particular data server has grown past EOF; the problem exists for		particular data server has grown past EOF; the problem exists for
	both dense and sparse layouts. Imagine the following scenario: a		both dense and sparse layouts. Imagine the following scenario: a
	client creates a new file (size == 0) and writes to byte 131072; the		client creates a new file (size == 0) and writes to byte 131072; the
	client then seeks to the beginning of the file and reads byte 100.		client then seeks to the beginning of the file and reads byte 100.
	The client should receive zeroes back as a result of the READ. However,		The client should receive zeroes back as a result of the READ. However,
	if the striping pattern directs the client to send the READ to		if the striping pattern directs the client to send the READ to
	a data server other than the one that received the		a data server other than the one that received the
	client's original WRITE, the data server servicing the READ may		client's original WRITE, the data server servicing the READ may
	believe that the file's size is still 0 bytes. In that event, the		believe that the file's size is still 0 bytes. In that event, the
	data server's READ response will contain zero bytes and an		data server's READ response will contain zero bytes and an
	indication of EOF. The data server can only return zeroes if it knows that		indication of EOF. The data server can only return zeroes if it knows that
	the file's size has been extended. This would require the immediate		the file's size has been extended. This would require the immediate
	propagation of the file's size to all data servers, which is		propagation of the file's size to all data servers, which is
	potentially very costly. Therefore, the client that has		potentially very costly. Therefore, the client that has
	initiated the extension of the file's size MUST be prepared to deal		initiated the extension of the file's size <bcp14>MUST</bcp14> be prepared to deal
	with these EOF conditions.		with these EOF conditions.
	When the offset in the arguments to READ		When the offset in the arguments to READ
	is less than the client's view of the file size, if the READ response		is less than the client's view of the file size, if the READ response
	indicates EOF and/or contains fewer bytes than requested, the client		indicates EOF and/or contains fewer bytes than requested, the client
	will interpret such a response as a hole in the file, and the		will interpret such a response as a hole in the file, and the
	NFS client will substitute zeroes for the data.		NFS client will substitute zeroes for the data.
	</t>		</t>
	<t>		<t>
	The NFSv4.1 protocol only provides close-to-open file data cache		The NFSv4.1 protocol only provides close-to-open file data cache
	semantics; meaning that when the file is closed, all modified data is		semantics; meaning that when the file is closed, all modified data is
	written to the server. When a subsequent OPEN of the file is		written to the server. When a subsequent OPEN of the file is
	done, the change attribute is inspected for a difference from a		done, the change attribute is inspected for a difference from a
	cached value for the change attribute. For the case above, this means		cached value for the change attribute. For the case above, this means
	that a LAYOUTCOMMIT will be done at close (along with the data		that a LAYOUTCOMMIT will be done at close (along with the data
	WRITEs) and will update the file's size and change attribute. Access		WRITEs) and will update the file's size and change attribute. Access
	from another client after that point will result in the appropriate		from another client after that point will result in the appropriate
	size being returned.		size being returned.
	</t>		</t>
	</section>		</section>
			<section anchor="file_layout_revoke" numbered="true" toc="default">
	<section title="Layout Revocation and Fencing" anchor="file_layout_revoke" >		<name>Layout Revocation and Fencing</name>
	<t>		<t>
	As described in <xref target="crash_recovery" />, the		As described in <xref target="crash_recovery" format="default"/>, the
	layout-type-specific storage protocol is responsible		layout-type-specific storage protocol is responsible
	for handling the effects of I/Os that started before		for handling the effects of I/Os that started before
	lease expiration and extend through lease expiration.		lease expiration and extend through lease expiration.
	The LAYOUT4_NFSV4_1_FILES layout type		The LAYOUT4_NFSV4_1_FILES layout type
	can prevent all I/Os to data servers from		can prevent all I/Os to data servers from
	being executed after lease expiration (this prevention is		being executed after lease expiration (this prevention is
	called "fencing"), without relying		called "fencing"), without relying
	on a precise client lease timer and without requiring		on a precise client lease timer and without requiring
	data servers to maintain lease timers. The		data servers to maintain lease timers. The
	LAYOUT4_NFSV4_1_FILES pNFS server has the flexibility to		LAYOUT4_NFSV4_1_FILES pNFS server has the flexibility to
	revoke individual layouts, and thus fence I/O on a per-file		revoke individual layouts, and thus fence I/O on a per-file
	basis.		basis.
	</t>		</t>
	<t>		<t>
	In addition to lease expiration,		In addition to lease expiration,
	the reasons a layout can be revoked include: client fails to respond to		the reasons a layout can be revoked include: client fails to respond to
	a CB_LAYOUTRECALL,		a CB_LAYOUTRECALL,
	the		the
	metadata server restarts, or administrative intervention. Regardless		metadata server restarts, or administrative intervention. Regardless
	of the reason, once a client's layout has been revoked, the pNFS		of the reason, once a client's layout has been revoked, the pNFS
	server MUST prevent the client from sending I/O for the affected file		server <bcp14>MUST</bcp14> prevent the client from sending I/O for the affecte
	from and to all data servers; in other words, it MUST fence the		d file
			from and to all data servers; in other words, it <bcp14>MUST</bcp14> fence the
	client from the affected file on the data servers.		client from the affected file on the data servers.
	</t>		</t>
	<t>		<t>
	Fencing works as follows. As described in <xref		Fencing works as follows. As described in <xref target="pnfs_session_stuff" fo
	target="pnfs_session_stuff" />, in COMPOUND procedure		rmat="default"/>, in COMPOUND procedure
	requests to the data server, the data filehandle provided		requests to the data server, the data filehandle provided
	by the PUTFH operation and the stateid in the READ or		by the PUTFH operation and the stateid in the READ or
	WRITE operation are used to ensure that the client has		WRITE operation are used to ensure that the client has
	a valid layout for the I/O being performed; if it does		a valid layout for the I/O being performed; if it does
	not, the I/O is rejected with NFS4ERR_PNFS_NO_LAYOUT.		not, the I/O is rejected with NFS4ERR_PNFS_NO_LAYOUT.
	The server can simply check the stateid and, additionally,		The server can simply check the stateid and, additionally,
	make the data filehandle stale if the layout specified		make the data filehandle stale if the layout specified
	a data filehandle that is different from the metadata server's		a data filehandle that is different from the metadata server's
	filehandle for the file (see the nfl_fh_list description in		filehandle for the file (see the nfl_fh_list description in
	<xref target="file_data_types" />).		<xref target="file_data_types" format="default"/>).
	</t>		</t>
	<t>		<t>
	Before the metadata server takes any action to revoke		Before the metadata server takes any action to revoke
	layout state given out by a previous instance, it must make		layout state given out by a previous instance, it must make
	sure that all layout state from that previous instance are		sure that all layout state from that previous instance are
	invalidated at the data servers. This has the following		invalidated at the data servers. This has the following
	implications.		implications.
	<list style='symbols'>		</t>
			<ul spacing="normal">
	<t>		<li>
	The metadata server must not restripe a		The metadata server must not restripe a
	file until it has contacted all of the data servers		file until it has contacted all of the data servers
	to invalidate the layouts from the previous instance.		to invalidate the layouts from the previous instance.
	</t>		</li>
			<li>
	<t>
	The metadata server must not give out mandatory locks that conflict with		The metadata server must not give out mandatory locks that conflict with
	layouts from the previous instance without either doing		layouts from the previous instance without either doing
	a specific layout invalidation (as it would have to do anyway)		a specific layout invalidation (as it would have to do anyway)
	or doing a global data server invalidation.		or doing a global data server invalidation.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
			<section anchor="file_security_considerations" numbered="true" toc="defaul
	</section>		t">
			<name>Security Considerations for the File Layout Type</name>
	<section title="Security Considerations for the File Layout Type" anchor="file_s		<t>
	ecurity_considerations">		The NFSv4.1 file layout type <bcp14>MUST</bcp14> adhere to the security
	<t>		considerations outlined in <xref target="security_considerations_pnfs" format=
	The NFSv4.1 file layout type MUST adhere to the security		"default"/>. NFSv4.1 data servers <bcp14>MUST</bcp14> make all of the
	considerations outlined in <xref target="security_considerations_pnfs"
	/>. NFSv4.1 data servers MUST make all of the
	required access checks on each READ or WRITE I/O as determined by		required access checks on each READ or WRITE I/O as determined by
	the NFSv4.1 protocol.		the NFSv4.1 protocol.
	If the metadata server would deny a READ or WRITE		If the metadata server would deny a READ or WRITE
	operation on a file due to its ACL, mode attribute, open		operation on a file due to its ACL, mode attribute, open
	access mode, open deny mode, mandatory byte-range lock state, or any other		access mode, open deny mode, mandatory byte-range lock state, or any other
	attributes and state, the data server MUST also deny the		attributes and state, the data server <bcp14>MUST</bcp14> also deny the
	READ or WRITE operation. This impacts the control		READ or WRITE operation. This impacts the control
	protocol and the propagation of state from the metadata		protocol and the propagation of state from the metadata
	server to the data servers; see <xref		server to the data servers; see <xref target="state_propagation" format="defau
	target="state_propagation" /> for more details.		lt"/> for more details.
	</t>		</t>
	<t>		<t>
	The methods for authentication,		The methods for authentication,
	integrity, and privacy for data servers based on the		integrity, and privacy for data servers based on the
	LAYOUT4_NFSV4_1_FILES layout type are the same as those used		LAYOUT4_NFSV4_1_FILES layout type are the same as those used
	by metadata servers. Metadata and data servers		by metadata servers. Metadata and data servers
	use ONC RPC security flavors to		use ONC RPC security flavors to
	authenticate, and SECINFO and SECINFO_NO_NAME		authenticate, and SECINFO and SECINFO_NO_NAME
	to negotiate the security mechanism and services		to negotiate the security mechanism and services
	to be used. Thus, when using the LAYOUT4_NFSV4_1_FILES layout type,		to be used. Thus, when using the LAYOUT4_NFSV4_1_FILES layout type,
	the impact on the RPC-based security		the impact on the RPC-based security
	model due to pNFS (as alluded to in Sections		model due to pNFS (as alluded to in Sections
	<xref target="rpc_and_security" format="counter"/>		<xref target="rpc_and_security" format="counter"/>
	and <xref target="parallel_access" format="counter"/>) is zero.		and <xref target="parallel_access" format="counter"/>) is zero.
	</t>		</t>
	<t>		<t>
	For a given file object, a metadata server		For a given file object, a metadata server
	MAY require different security parameters		<bcp14>MAY</bcp14> require different security parameters
	(secinfo4 value) than the data server.		(secinfo4 value) than the data server.
	For a given file object with multiple data servers,		For a given file object with multiple data servers,
	the secinfo4 value SHOULD be the same across		the secinfo4 value <bcp14>SHOULD</bcp14> be the same across
	all data servers. If the secinfo4 values across a metadata server		all data servers. If the secinfo4 values across a metadata server
	and its data servers differ for a specific file, the		and its data servers differ for a specific file, the
	mapping of the principal to the server's internal user identifier		mapping of the principal to the server's internal user identifier
	MUST be the same in order for the access-control checks based on		<bcp14>MUST</bcp14> be the same in order for the access-control checks based o n
	ACL, mode, open and deny mode, and mandatory locking to be		ACL, mode, open and deny mode, and mandatory locking to be
	consistent across on the pNFS server.		consistent across on the pNFS server.
	</t>		</t>
	<t>		<t>
	If an NFSv4.1 implementation supports		If an NFSv4.1 implementation supports
	pNFS and supports NFSv4.1 file layouts, then the		pNFS and supports NFSv4.1 file layouts, then the
	implementation MUST support the SECINFO_NO_NAME operation on both		implementation <bcp14>MUST</bcp14> support the SECINFO_NO_NAME operation on bo th
	the metadata and data servers.		the metadata and data servers.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		<section anchor="internationalization" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Internationalization</name>
	$ -->		<t>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="internationalization" title="Internationalization">
	<t>
	The primary issue in which NFSv4.1 needs to deal with		The primary issue in which NFSv4.1 needs to deal with
	internationalization, or I18N, is with respect to file names and other		internationalization, or I18N, is with respect to file names and other
	strings as used within the protocol. The choice of string		strings as used within the protocol. The choice of string
	representation must allow reasonable name/string access to clients		representation must allow reasonable name/string access to clients
	that use various languages. The UTF-8 encoding of the UCS (Universal		that use various languages. The UTF-8 encoding of the UCS (Universal
	Multiple-Octet Coded Character Set) as defined		Multiple-Octet Coded Character Set) as defined
	by <xref target="ISO.10646-1.1993">ISO10646</xref> allows for this type		by <xref target="ISO.10646-1.1993" format="default">ISO10646</xref> allows for t his type
	of access and follows the policy described in "IETF Policy on		of access and follows the policy described in "IETF Policy on
	Character Sets and Languages", <xref target="RFC2277">RFC 2277</xref>.		Character Sets and Languages", <xref target="RFC2277" format="default">RFC 2277< /xref>.
	</t>		</t>
	<t>		<t>
	<xref target="RFC3454">RFC 3454</xref>, otherwise known as "stringprep", documen		<xref target="RFC3454" format="default">RFC 3454</xref>, otherwise known as "str
	ts a		ingprep", documents a
	framework for using Unicode/UTF-8 in networking protocols so as "to		framework for using Unicode/UTF-8 in networking protocols so as "to
	increase the likelihood that string input and string comparison work		increase the likelihood that string input and string comparison work
	in ways that make sense for typical users throughout the world". A		in ways that make sense for typical users throughout the world". A
	protocol must define a profile of stringprep "in order to fully		protocol must define a profile of stringprep "in order to fully
	specify the processing options". The remainder of this		specify the processing options". The remainder of this
	section defines the NFSv4.1 stringprep profiles. Much of the terminology		section defines the NFSv4.1 stringprep profiles. Much of the terminology
	used for the remainder of this section comes from stringprep.		used for the remainder of this section comes from stringprep.
	</t>		</t>
	<t>		<t>
	There are three UTF-8 string types defined for NFSv4.1:		There are three UTF-8 string types defined for NFSv4.1:
	utf8str_cs, utf8str_cis, and utf8str_mixed. Separate profiles are		utf8str_cs, utf8str_cis, and utf8str_mixed. Separate profiles are
	defined for each. Each profile defines the following, as required by		defined for each. Each profile defines the following, as required by
	stringprep:		stringprep:
	<list style='symbols'>
	<t>
	The intended applicability of the profile.
	</t>		</t>
	<t>		<ul spacing="normal">
			<li>
			The intended applicability of the profile.
			</li>
			<li>
	The character repertoire that is the input and output to stringprep		The character repertoire that is the input and output to stringprep
	(which is Unicode 3.2 for the referenced version of stringprep).		(which is Unicode 3.2 for the referenced version of stringprep).
	However, NFSv4.1 implementations are not limited to 3.2.		However, NFSv4.1 implementations are not limited to 3.2.
	</t>		</li>
	<t>		<li>
	The mapping tables from stringprep used (as described in Section 3 of		The mapping tables from stringprep used (as described in Section
	stringprep).		<xref target="RFC3454" sectionFormat="bare" section="3"/> of stringprep).
	</t>		</li>
	<t>		<li>
	Any additional mapping tables specific to the profile.		Any additional mapping tables specific to the profile.
	</t>		</li>
	<t>		<li>
	The Unicode normalization used, if any (as described in Section 4 of stringprep)		The Unicode normalization used, if any (as described in Section
	.		<xref target="RFC3454" sectionFormat="bare" section="4"/> of stringprep).
	</t>		</li>
	<t>		<li>
	The tables from the stringprep listing of characters that are prohibited		The tables from the stringprep listing of characters that are prohibited
	as output (as described in Section 5 of stringprep).		as output (as described in Section <xref target="RFC3454" sectionFormat="bare" s
	</t>		ection="5"/> of stringprep).
	<t>		</li>
	The bidirectional string testing used, if any (as described in Section 6 of stri		<li>
	ngprep).		The bidirectional string testing used, if any (as described in Section <xref tar
	</t>		get="RFC3454" sectionFormat="bare" section="6"/> of stringprep).
	<t>		</li>
			<li>
	Any additional characters that are prohibited as output specific to		Any additional characters that are prohibited as output specific to
	the profile.		the profile.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Stringprep discusses Unicode characters, whereas NFSv4.1 renders		Stringprep discusses Unicode characters, whereas NFSv4.1 renders
	UTF-8 characters. Since there is a one-to-one mapping from UTF-8 to		UTF-8 characters. Since there is a one-to-one mapping from UTF-8 to
	Unicode, when the remainder of this document refers to Unicode,		Unicode, when the remainder of this document refers to Unicode,
	the reader should assume UTF-8.		the reader should assume UTF-8.
	</t>		</t>
	<t>		<t>
	Much of the text for the profiles comes from <xref target="RFC3491">RFC 3491</xr		Much of the text for the profiles comes from RFC 3491 <xref target="RFC3491" for
	ef>.		mat="default"/>.
	</t>		</t>
	<section title="Stringprep Profile for the utf8str_cs Type">		<section numbered="true" toc="default">
	<t>		<name>Stringprep Profile for the utf8str_cs Type</name>
			<t>
	Every use of the utf8str_cs type definition in the NFSv4 protocol specification follows the profile named		Every use of the utf8str_cs type definition in the NFSv4 protocol specification follows the profile named
	nfs4_cs_prep.		nfs4_cs_prep.
	</t>		</t>
	<section toc="exclude" title="Intended Applicability of the nfs4_cs_prep Profile		<section toc="exclude" numbered="true">
	">		<name>Intended Applicability of the nfs4_cs_prep Profile</name>
	<t>		<t>
	The utf8str_cs type is a case-sensitive string of UTF-8 characters.		The utf8str_cs type is a case-sensitive string of UTF-8 characters.
	Its primary use in NFSv4.1 is for naming components and		Its primary use in NFSv4.1 is for naming components and
	pathnames. Components and pathnames are stored on the server's		pathnames. Components and pathnames are stored on the server's
	file system. Two valid distinct UTF-8 strings might be the same after		file system. Two valid distinct UTF-8 strings might be the same after
	processing via the utf8str_cs profile. If the strings are two names		processing via the utf8str_cs profile. If the strings are two names
	inside a directory, the NFSv4.1 server will need to either:		inside a directory, the NFSv4.1 server will need to either:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	disallow the creation of a second name if its post-processed form		disallow the creation of a second name if its post-processed form
	collides with that of an existing name, or		collides with that of an existing name, or
	</t>		</li>
	<t>		<li>
	allow the creation of the second name, but arrange so that after		allow the creation of the second name, but arrange so that after
	post-processing, the second name is different than the post-processed		post-processing, the second name is different than the post-processed
	form of the first name.		form of the first name.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section toc="exclude" numbered="true">
	<section toc="exclude" title="Character Repertoire of nfs4_cs_prep">		<name>Character Repertoire of nfs4_cs_prep</name>
	<t>		<t>
	The nfs4_cs_prep profile uses Unicode 3.2, as defined in stringprep's		The nfs4_cs_prep profile uses Unicode 3.2, as defined in stringprep's
	Appendix A.1.		Appendix A.1.
	However, NFSv4.1 implementations are not limited to 3.2.		However, NFSv4.1 implementations are not limited to 3.2.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" title="Mapping Used by nfs4_cs_prep">		<section toc="exclude" numbered="true">
	<t>		<name>Mapping Used by nfs4_cs_prep</name>
			<t>
	The nfs4_cs_prep profile specifies mapping using the		The nfs4_cs_prep profile specifies mapping using the
	following tables from stringprep:		following tables from stringprep:
	<list style='empty'>
	<t>
	Table B.1
	</t>
	</list>
	</t>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
			Table B.1
			</li>
			</ul>
			<t>
	Table B.2 is normally not part of the nfs4_cs_prep profile as it is		Table B.2 is normally not part of the nfs4_cs_prep profile as it is
	primarily for dealing with case-insensitive comparisons. However, if		primarily for dealing with case-insensitive comparisons. However, if
	the NFSv4.1 file server supports the case_insensitive file system		the NFSv4.1 file server supports the case_insensitive file system
	attribute, and if case_insensitive is TRUE, the NFSv4.1 server		attribute, and if case_insensitive is TRUE, the NFSv4.1 server
	MUST use Table B.2 (in addition to Table B1) when processing		<bcp14>MUST</bcp14> use Table B.2 (in addition to Table B1) when processing
	utf8str_cs strings, and the NFSv4.1 client MUST assume Table B.2		utf8str_cs strings, and the NFSv4.1 client <bcp14>MUST</bcp14> assume Table B.2
	(in addition to Table B.1) is being used.		(in addition to Table B.1) is being used.
	</t>		</t>
	<t>		<t>
	If the case_preserving attribute is present and set to FALSE, then the		If the case_preserving attribute is present and set to FALSE, then the
	NFSv4.1 server MUST use Table B.2 to map case when processing		NFSv4.1 server <bcp14>MUST</bcp14> use Table B.2 to map case when processing
	utf8str_cs strings. Whether the server maps from lower to upper case		utf8str_cs strings. Whether the server maps from lower to upper case
	or from upper to lower case is an implementation dependency.		or from upper to lower case is an implementation dependency.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" title="Normalization used by nfs4_cs_prep">		<section toc="exclude" numbered="true">
	<t>		<name>Normalization used by nfs4_cs_prep</name>
			<t>
	The nfs4_cs_prep profile does not specify a normalization form. A		The nfs4_cs_prep profile does not specify a normalization form. A
	later revision of this specification may specify a particular		later revision of this specification may specify a particular
	normalization form. Therefore, the server and client can expect that		normalization form. Therefore, the server and client can expect that
	they may receive unnormalized characters within protocol requests and		they may receive unnormalized characters within protocol requests and
	responses. If the operating environment requires normalization, then		responses. If the operating environment requires normalization, then
	the implementation must normalize utf8str_cs strings within the		the implementation must normalize utf8str_cs strings within the
	protocol before presenting the information to an application (at the		protocol before presenting the information to an application (at the
	client) or local file system (at the server).		client) or local file system (at the server).
	</t>		</t>
	</section>		</section>
	<section toc="exclude" title="Prohibited Output for nfs4_cs_prep">		<section toc="exclude" numbered="true">
	<t>		<name>Prohibited Output for nfs4_cs_prep</name>
			<t>
	The nfs4_cs_prep profile RECOMMENDS prohibiting the use of the		The nfs4_cs_prep profile RECOMMENDS prohibiting the use of the
	following tables from stringprep:		following tables from stringprep:
	<list style='empty'>
	<t>Table C.5</t>
	<t>Table C.6</t>
	</list>
	</t>		</t>
	</section>		<ul empty="true" spacing="normal">
	<section toc="exclude" title="Bidirectional Output for nfs4_cs_prep">		<li>Table C.5</li>
	<t>		<li>Table C.6</li>
			</ul>
			</section>
			<section toc="exclude" numbered="true">
			<name>Bidirectional Output for nfs4_cs_prep</name>
			<t>
	The nfs4_cs_prep profile does not specify any checking of		The nfs4_cs_prep profile does not specify any checking of
	bidirectional strings.		bidirectional strings.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section title="Stringprep Profile for the utf8str_cis Type">		<section numbered="true" toc="default">
	<t>		<name>Stringprep Profile for the utf8str_cis Type</name>
			<t>
	Every use of the utf8str_cis type definition in the NFSv4.1		Every use of the utf8str_cis type definition in the NFSv4.1
	protocol specification follows the profile named nfs4_cis_prep.		protocol specification follows the profile named nfs4_cis_prep.
	</t>		</t>
	<section toc="exclude" title="Intended Applicability of the nfs4_cis_prep Profil		<section toc="exclude" numbered="true">
	e">		<name>Intended Applicability of the nfs4_cis_prep Profile</name>
	<t>		<t>
	The utf8str_cis type is a case-insensitive string of		The utf8str_cis type is a case-insensitive string of
	UTF-8 characters. Its primary use in NFSv4.1 is		UTF-8 characters. Its primary use in NFSv4.1 is
	for naming NFS servers.		for naming NFS servers.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" title="Character Repertoire of nfs4_cis_prep">		<section toc="exclude" numbered="true">
	<t>		<name>Character Repertoire of nfs4_cis_prep</name>
			<t>
	The nfs4_cis_prep profile uses Unicode 3.2, as defined in stringprep's		The nfs4_cis_prep profile uses Unicode 3.2, as defined in stringprep's
	Appendix A.1. However, NFSv4.1 implementations are not limited to 3.2.		Appendix A.1. However, NFSv4.1 implementations are not limited to 3.2.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" title="Mapping Used by nfs4_cis_prep">		<section toc="exclude" numbered="true">
	<t>		<name>Mapping Used by nfs4_cis_prep</name>
			<t>
	The nfs4_cis_prep profile specifies mapping using the following tables from		The nfs4_cis_prep profile specifies mapping using the following tables from
	stringprep:		stringprep:
	<list style='empty'>
	<t>Table B.1</t>
	<t>Table B.2</t>
	</list>
	</t>		</t>
	</section>		<ul empty="true" spacing="normal">
	<section toc="exclude" title="Normalization Used by nfs4_cis_prep">		<li>Table B.1</li>
	<t>		<li>Table B.2</li>
			</ul>
			</section>
			<section toc="exclude" numbered="true">
			<name>Normalization Used by nfs4_cis_prep</name>
			<t>
	The nfs4_cis_prep profile specifies using Unicode normalization form		The nfs4_cis_prep profile specifies using Unicode normalization form
	KC, as described in stringprep.		KC, as described in stringprep.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" title="Prohibited Output for nfs4_cis_prep">		<section toc="exclude" numbered="true">
	<t>		<name>Prohibited Output for nfs4_cis_prep</name>
			<t>
	The nfs4_cis_prep profile specifies prohibiting using the following		The nfs4_cis_prep profile specifies prohibiting using the following
	tables from stringprep:		tables from stringprep:
	<list style='empty'>
	<t>Table C.1.2</t>
	<t>Table C.2.2</t>
	<t>Table C.3</t>
	<t>Table C.4</t>
	<t>Table C.5</t>
	<t>Table C.6</t>
	<t>Table C.7</t>
	<t>Table C.8</t>
	<t>Table C.9</t>
	</list>
	</t>		</t>
	</section>		<ul empty="true" spacing="normal">
	<section toc="exclude" title="Bidirectional Output for nfs4_cis_prep">		<li>Table C.1.2</li>
	<t>		<li>Table C.2.2</li>
			<li>Table C.3</li>
			<li>Table C.4</li>
			<li>Table C.5</li>
			<li>Table C.6</li>
			<li>Table C.7</li>
			<li>Table C.8</li>
			<li>Table C.9</li>
			</ul>
			</section>
			<section toc="exclude" numbered="true">
			<name>Bidirectional Output for nfs4_cis_prep</name>
			<t>
	The nfs4_cis_prep profile specifies checking bidirectional strings as		The nfs4_cis_prep profile specifies checking bidirectional strings as
	described in stringprep's Section 6.		described in stringprep's Section <xref target="RFC3454" sectionFormat="bare" se ction="6"/>.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section title="Stringprep Profile for the utf8str_mixed Type">		<section numbered="true" toc="default">
	<t>		<name>Stringprep Profile for the utf8str_mixed Type</name>
			<t>
	Every use of the utf8str_mixed type definition in the NFSv4.1		Every use of the utf8str_mixed type definition in the NFSv4.1
	protocol specification follows the profile named nfs4_mixed_prep.		protocol specification follows the profile named nfs4_mixed_prep.
	</t>		</t>
	<section toc="exclude" title="Intended Applicability of the nfs4_mixed_prep Prof		<section toc="exclude" numbered="true">
	ile">		<name>Intended Applicability of the nfs4_mixed_prep Profile</name>
	<t>		<t>
	The utf8str_mixed type is a string of UTF-8 characters, with a prefix		The utf8str_mixed type is a string of UTF-8 characters, with a prefix
	that is case sensitive, a separator equal to '@', and a suffix that is a		that is case sensitive, a separator equal to '@', and a suffix that is a
	fully qualified domain name. Its primary use in NFSv4.1 is for		fully qualified domain name. Its primary use in NFSv4.1 is for
	naming principals identified in an Access Control Entry.		naming principals identified in an Access Control Entry.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" title="Character Repertoire of nfs4_mixed_prep">		<section toc="exclude" numbered="true">
	<t>		<name>Character Repertoire of nfs4_mixed_prep</name>
			<t>
	The nfs4_mixed_prep profile uses Unicode 3.2, as defined in		The nfs4_mixed_prep profile uses Unicode 3.2, as defined in
	stringprep's Appendix A.1.		stringprep's Appendix A.1.
	However, NFSv4.1 implementations are not limited to 3.2.		However, NFSv4.1 implementations are not limited to 3.2.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" title="Mapping Used by nfs4_cis_prep">		<section toc="exclude" numbered="true">
	<t>		<name>Mapping Used by nfs4_cis_prep</name>
			<t>
	For the prefix and the separator of a utf8str_mixed		For the prefix and the separator of a utf8str_mixed
	string, the nfs4_mixed_prep profile specifies mapping		string, the nfs4_mixed_prep profile specifies mapping
	using the following table from stringprep:		using the following table from stringprep:
	<list style='empty'>
	<t>Table B.1</t>
	</list>
	</t>		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>Table B.1</li>
			</ul>
			<t>
	For the suffix of a utf8str_mixed string, the nfs4_mixed_prep		For the suffix of a utf8str_mixed string, the nfs4_mixed_prep
	profile specifies mapping using the following tables from		profile specifies mapping using the following tables from
	stringprep:		stringprep:
	<list style='empty'>
	<t>Table B.1</t>
	<t>Table B.2</t>
	</list>
	</t>		</t>
	</section>		<ul empty="true" spacing="normal">
	<section toc="exclude" title="Normalization Used by nfs4_mixed_prep">		<li>Table B.1</li>
	<t>		<li>Table B.2</li>
			</ul>
			</section>
			<section toc="exclude" numbered="true">
			<name>Normalization Used by nfs4_mixed_prep</name>
			<t>
	The nfs4_mixed_prep profile specifies using Unicode normalization form		The nfs4_mixed_prep profile specifies using Unicode normalization form
	KC, as described in stringprep.		KC, as described in stringprep.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" title="Prohibited Output for nfs4_mixed_prep">		<section toc="exclude" numbered="true">
	<t>		<name>Prohibited Output for nfs4_mixed_prep</name>
			<t>
	The nfs4_mixed_prep profile specifies prohibiting using the		The nfs4_mixed_prep profile specifies prohibiting using the
	following tables from stringprep:		following tables from stringprep:
	<list style='empty'>
	<t>Table C.1.2</t>
	<t>Table C.2.2</t>
	<t>Table C.3</t>
	<t>Table C.4</t>
	<t>Table C.5</t>
	<t>Table C.6</t>
	<t>Table C.7</t>
	<t>Table C.8</t>
	<t>Table C.9</t>
	</list>
	</t>		</t>
	</section>		<ul empty="true" spacing="normal">
	<section toc="exclude" title="Bidirectional Output for nfs4_mixed_prep">		<li>Table C.1.2</li>
	<t>		<li>Table C.2.2</li>
			<li>Table C.3</li>
			<li>Table C.4</li>
			<li>Table C.5</li>
			<li>Table C.6</li>
			<li>Table C.7</li>
			<li>Table C.8</li>
			<li>Table C.9</li>
			</ul>
			</section>
			<section toc="exclude" numbered="true">
			<name>Bidirectional Output for nfs4_mixed_prep</name>
			<t>
	The nfs4_mixed_prep profile specifies checking bidirectional strings		The nfs4_mixed_prep profile specifies checking bidirectional strings
	as described in stringprep's Section 6.		as described in stringprep's Section <xref target="RFC3454" sectionFormat="bare" section="6"/>.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section title="UTF-8 Capabilities" anchor="utf8_caps">		<section anchor="utf8_caps" numbered="true" toc="default">
	<figure>		<name>UTF-8 Capabilities</name>
	<artwork>		<sourcecode type="xdr"><![CDATA[
	const FSCHARSET_CAP4_CONTAINS_NON_UTF8 = 0x1;		const FSCHARSET_CAP4_CONTAINS_NON_UTF8 = 0x1;
	const FSCHARSET_CAP4_ALLOWS_ONLY_UTF8 = 0x2;		const FSCHARSET_CAP4_ALLOWS_ONLY_UTF8 = 0x2;
	typedef uint32_t fs_charset_cap4;		typedef uint32_t fs_charset_cap4;]]></sourcecode>
	</artwork>		<t>
	</figure>
	<t>
	Because some operating environments and file systems do		Because some operating environments and file systems do
	not enforce character set encodings, NFSv4.1 supports the		not enforce character set encodings, NFSv4.1 supports the
	fs_charset_cap attribute (<xref target="attrdef_fs_charset_cap"/>)		fs_charset_cap attribute (<xref target="attrdef_fs_charset_cap" format="default" />)
	that indicates to the client a file system's UTF-8 capabilities.		that indicates to the client a file system's UTF-8 capabilities.
	The attribute is an integer containing a pair of flags.		The attribute is an integer containing a pair of flags.
	The first flag is FSCHARSET_CAP4_CONTAINS_NON_UTF8, which, if set		The first flag is FSCHARSET_CAP4_CONTAINS_NON_UTF8, which, if set
	to one, tells the client that the file system contains non-UTF-8 characters,		to one, tells the client that the file system contains non-UTF-8 characters,
	and the server will not convert non-UTF characters to UTF-8 if the client		and the server will not convert non-UTF characters to UTF-8 if the client
	reads a symbolic link or directory, neither will operations with component		reads a symbolic link or directory, neither will operations with component
	names or pathnames in the arguments convert the strings to UTF-8.		names or pathnames in the arguments convert the strings to UTF-8.
	The second flag is FSCHARSET_CAP4_ALLOWS_ONLY_UTF8, which, if set to		The second flag is FSCHARSET_CAP4_ALLOWS_ONLY_UTF8, which, if set to
	one, indicates that the server will accept (and generate) only		one, indicates that the server will accept (and generate) only
	UTF-8 characters on the file system. If		UTF-8 characters on the file system. If
	FSCHARSET_CAP4_ALLOWS_ONLY_UTF8 is set to one,		FSCHARSET_CAP4_ALLOWS_ONLY_UTF8 is set to one,
	FSCHARSET_CAP4_CONTAINS_NON_UTF8 MUST be set to zero.		FSCHARSET_CAP4_CONTAINS_NON_UTF8 <bcp14>MUST</bcp14> be set to zero.
	FSCHARSET_CAP4_ALLOWS_ONLY_UTF8 SHOULD always be set to one.		FSCHARSET_CAP4_ALLOWS_ONLY_UTF8 <bcp14>SHOULD</bcp14> always be set to one.
	</t>		</t>
	</section>		</section>
	<section title="UTF-8 Related Errors" anchor="utf8_related_errors">		<section anchor="utf8_related_errors" numbered="true" toc="default">
	<t>		<name>UTF-8 Related Errors</name>
			<t>
	Where the client sends an invalid UTF-8 string, the server should		Where the client sends an invalid UTF-8 string, the server should
	return NFS4ERR_INVAL (see <xref target="error_definitions"/>).		return NFS4ERR_INVAL (see <xref target="error_definitions" format="default"/>).
	This includes cases in which inappropriate prefixes are detected and		This includes cases in which inappropriate prefixes are detected and
	where the count includes trailing bytes that do not constitute a full		where the count includes trailing bytes that do not constitute a full
	UCS character.		UCS character.
	</t>		</t>
	<t>		<t>
	Where the client-supplied string is valid UTF-8 but contains		Where the client-supplied string is valid UTF-8 but contains
	characters that are not supported by the server as a value for that		characters that are not supported by the server as a value for that
	string (e.g., names containing characters outside of Unicode plane 0 on		string (e.g., names containing characters outside of Unicode plane 0 on
	file systems that fail to support such characters despite their		file systems that fail to support such characters despite their
	presence in the Unicode standard), the server should return		presence in the Unicode standard), the server should return
	NFS4ERR_BADCHAR.		NFS4ERR_BADCHAR.
	</t>		</t>
	<t>		<t>
	Where a UTF-8 string is used as a file name, and the file system (while		Where a UTF-8 string is used as a file name, and the file system (while
	supporting all of the characters within the name) does not allow that		supporting all of the characters within the name) does not allow that
	particular name to be used, the server should return the error <xref		particular name to be used, the server should return the error <xref target="err
	target="error_definitions">NFS4ERR_BADNAME</xref>. This includes		or_definitions" format="default">NFS4ERR_BADNAME</xref>. This includes
	situations in which the server file system imposes a normalization		situations in which the server file system imposes a normalization
	constraint on name strings, but will also include such situations as		constraint on name strings, but will also include such situations as
	file system prohibitions of "." and ".." as file names for certain		file system prohibitions of "." and ".." as file names for certain
	operations, and other such constraints.		operations, and other such constraints.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->
	<!-- Copyright (C) The IETF Trust (2007-2008) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section title="Error Values">		<section numbered="true" toc="default">
	<t>		<name>Error Values</name>
			<t>
	NFS error numbers are assigned to failed operations within a		NFS error numbers are assigned to failed operations within a
	Compound (COMPOUND or CB_COMPOUND) request. A Compound request		Compound (COMPOUND or CB_COMPOUND) request. A Compound request
	contains a number of NFS operations that have their results		contains a number of NFS operations that have their results
	encoded in sequence in a Compound reply. The results of successful		encoded in sequence in a Compound reply. The results of successful
	operations will consist of an NFS4_OK status followed by the		operations will consist of an NFS4_OK status followed by the
	encoded results of the operation. If an NFS operation fails, an		encoded results of the operation. If an NFS operation fails, an
	error status will be entered in the reply and the Compound		error status will be entered in the reply and the Compound
	request will be terminated.		request will be terminated.
	</t>		</t>
	<section title="Error Definitions">		<section numbered="true" toc="default">
	<texttable anchor='error_definitions'>		<name>Error Definitions</name>
	<preamble>		<table anchor="error_definitions" align="center">
	Protocol Error Definitions		<name> Protocol Error Definitions</name>
	</preamble>		<thead>
	<ttcol align='left'>Error</ttcol>		<tr>
	<ttcol align='left'>Number</ttcol>		<th align="left">Error</th>
	<ttcol align='left'>Description</ttcol>		<th align="left">Number</th>
			<th align="left">Description</th>
	<c>NFS4_OK</c>		</tr>
	<c>0</c>		</thead>
	<c><xref target="err_OK" /></c>		<tbody>
			<tr>
	<c>NFS4ERR_ACCESS</c>		<td align="left">NFS4_OK</td>
	<c>13</c>		<td align="left">0</td>
	<c><xref target="err_ACCESS" /></c>		<td align="left">
			<xref target="err_OK" format="default"/></td>
	<c>NFS4ERR_ATTRNOTSUPP</c>		</tr>
	<c>10032</c>		<tr>
	<c><xref target="err_ATTRNOTSUPP" /></c>		<td align="left">NFS4ERR_ACCESS</td>
			<td align="left">13</td>
	<c>NFS4ERR_ADMIN_REVOKED</c>		<td align="left">
	<c>10047</c>		<xref target="err_ACCESS" format="default"/></td>
	<c><xref target="err_ADMIN_REVOKED" /></c>		</tr>
			<tr>
	<c>NFS4ERR_BACK_CHAN_BUSY</c>		<td align="left">NFS4ERR_ATTRNOTSUPP</td>
	<c>10057</c>		<td align="left">10032</td>
	<c><xref target="err_BACK_CHAN_BUSY" /></c>		<td align="left">
			<xref target="err_ATTRNOTSUPP" format="default"/></td>
	<c>NFS4ERR_BADCHAR</c>		</tr>
	<c>10040</c>		<tr>
	<c><xref target="err_BADCHAR" /></c>		<td align="left">NFS4ERR_ADMIN_REVOKED</td>
			<td align="left">10047</td>
	<c>NFS4ERR_BADHANDLE</c>		<td align="left">
	<c>10001</c>		<xref target="err_ADMIN_REVOKED" format="default"/></td>
	<c><xref target="err_BADHANDLE" /></c>		</tr>
			<tr>
	<c>NFS4ERR_BADIOMODE</c>		<td align="left">NFS4ERR_BACK_CHAN_BUSY</td>
	<c>10049</c>		<td align="left">10057</td>
	<c><xref target="err_BADIOMODE" /></c>		<td align="left">
			<xref target="err_BACK_CHAN_BUSY" format="default"/></td>
	<c>NFS4ERR_BADLAYOUT</c>		</tr>
	<c>10050</c>		<tr>
	<c><xref target="err_BADLAYOUT" /></c>		<td align="left">NFS4ERR_BADCHAR</td>
			<td align="left">10040</td>
	<c>NFS4ERR_BADNAME</c>		<td align="left">
	<c>10041</c>		<xref target="err_BADCHAR" format="default"/></td>
	<c><xref target="err_BADNAME" /></c>		</tr>
			<tr>
	<c>NFS4ERR_BADOWNER</c>		<td align="left">NFS4ERR_BADHANDLE</td>
	<c>10039</c>		<td align="left">10001</td>
	<c><xref target="err_BADOWNER" /></c>		<td align="left">
			<xref target="err_BADHANDLE" format="default"/></td>
	<c>NFS4ERR_BADSESSION</c>		</tr>
	<c>10052</c>		<tr>
	<c><xref target="err_BADSESSION" /></c>		<td align="left">NFS4ERR_BADIOMODE</td>
			<td align="left">10049</td>
	<c>NFS4ERR_BADSLOT</c>		<td align="left">
	<c>10053</c>		<xref target="err_BADIOMODE" format="default"/></td>
	<c><xref target="err_BADSLOT" /></c>		</tr>
			<tr>
	<c>NFS4ERR_BADTYPE</c>		<td align="left">NFS4ERR_BADLAYOUT</td>
	<c>10007</c>		<td align="left">10050</td>
	<c><xref target="err_BADTYPE" /></c>		<td align="left">
			<xref target="err_BADLAYOUT" format="default"/></td>
	<c>NFS4ERR_BADXDR</c>		</tr>
	<c>10036</c>		<tr>
	<c><xref target="err_BADXDR" /></c>		<td align="left">NFS4ERR_BADNAME</td>
			<td align="left">10041</td>
	<c>NFS4ERR_BAD_COOKIE</c>		<td align="left">
	<c>10003</c>		<xref target="err_BADNAME" format="default"/></td>
	<c><xref target="err_BAD_COOKIE" /></c>		</tr>
			<tr>
	<c>NFS4ERR_BAD_HIGH_SLOT</c>		<td align="left">NFS4ERR_BADOWNER</td>
	<c>10077</c>		<td align="left">10039</td>
	<c><xref target="err_BAD_HIGH_SLOT" /></c>		<td align="left">
			<xref target="err_BADOWNER" format="default"/></td>
	<c>NFS4ERR_BAD_RANGE</c>		</tr>
	<c>10042</c>		<tr>
	<c><xref target="err_BAD_RANGE" /></c>		<td align="left">NFS4ERR_BADSESSION</td>
			<td align="left">10052</td>
	<c>NFS4ERR_BAD_SEQID</c>		<td align="left">
	<c>10026</c>		<xref target="err_BADSESSION" format="default"/></td>
	<c><xref target="err_BAD_SEQID" /></c>		</tr>
			<tr>
	<c>NFS4ERR_BAD_SESSION_DIGEST</c>		<td align="left">NFS4ERR_BADSLOT</td>
	<c>10051</c>		<td align="left">10053</td>
	<c><xref target="err_BAD_SESSION_DIGEST" /></c>		<td align="left">
			<xref target="err_BADSLOT" format="default"/></td>
	<c>NFS4ERR_BAD_STATEID</c>		</tr>
	<c>10025</c>		<tr>
	<c><xref target="err_BAD_STATEID" /></c>		<td align="left">NFS4ERR_BADTYPE</td>
			<td align="left">10007</td>
	<c>NFS4ERR_CB_PATH_DOWN</c>		<td align="left">
	<c>10048</c>		<xref target="err_BADTYPE" format="default"/></td>
	<c><xref target="err_CB_PATH_DOWN" /></c>		</tr>
			<tr>
	<c>NFS4ERR_CLID_INUSE</c>		<td align="left">NFS4ERR_BADXDR</td>
	<c>10017</c>		<td align="left">10036</td>
	<c><xref target="err_CLID_INUSE" /></c>		<td align="left">
			<xref target="err_BADXDR" format="default"/></td>
	<c>NFS4ERR_CLIENTID_BUSY</c>		</tr>
	<c>10074</c>		<tr>
	<c><xref target="err_CLIENTID_BUSY" /></c>		<td align="left">NFS4ERR_BAD_COOKIE</td>
			<td align="left">10003</td>
	<c>NFS4ERR_COMPLETE_ALREADY</c>		<td align="left">
	<c>10054</c>		<xref target="err_BAD_COOKIE" format="default"/></td>
	<c><xref target="err_COMPLETE_ALREADY" /></c>		</tr>
			<tr>
	<c>NFS4ERR_CONN_NOT_BOUND_TO_SESSION</c>		<td align="left">NFS4ERR_BAD_HIGH_SLOT</td>
	<c>10055</c>		<td align="left">10077</td>
	<c><xref target="err_CONN_NOT_BOUND_TO_SESSION" /></c>		<td align="left">
			<xref target="err_BAD_HIGH_SLOT" format="default"/></td>
	<c>NFS4ERR_DEADLOCK</c>		</tr>
	<c>10045</c>		<tr>
	<c><xref target="err_DEADLOCK" /></c>		<td align="left">NFS4ERR_BAD_RANGE</td>
			<td align="left">10042</td>
	<c>NFS4ERR_DEADSESSION</c>		<td align="left">
	<c>10078</c>		<xref target="err_BAD_RANGE" format="default"/></td>
	<c><xref target="err_DEADSESSION" /></c>		</tr>
			<tr>
	<c>NFS4ERR_DELAY</c>		<td align="left">NFS4ERR_BAD_SEQID</td>
	<c>10008</c>		<td align="left">10026</td>
	<c><xref target="err_DELAY" /></c>		<td align="left">
			<xref target="err_BAD_SEQID" format="default"/></td>
	<c>NFS4ERR_DELEG_ALREADY_WANTED</c>		</tr>
	<c>10056</c>		<tr>
	<c><xref target="err_DELEG_ALREADY_WANTED" /></c>		<td align="left">NFS4ERR_BAD_SESSION_DIGEST</td>
			<td align="left">10051</td>
	<c>NFS4ERR_DELEG_REVOKED</c>		<td align="left">
	<c>10087</c>		<xref target="err_BAD_SESSION_DIGEST" format="default"/></td>
	<c><xref target="err_DELEG_REVOKED" /></c>		</tr>
			<tr>
	<c>NFS4ERR_DENIED</c>		<td align="left">NFS4ERR_BAD_STATEID</td>
	<c>10010</c>		<td align="left">10025</td>
	<c><xref target="err_DENIED" /></c>		<td align="left">
			<xref target="err_BAD_STATEID" format="default"/></td>
	<c>NFS4ERR_DIRDELEG_UNAVAIL</c>		</tr>
	<c>10084</c>		<tr>
	<c><xref target="err_DIRDELEG_UNAVAIL" /></c>		<td align="left">NFS4ERR_CB_PATH_DOWN</td>
			<td align="left">10048</td>
	<c>NFS4ERR_DQUOT</c>		<td align="left">
	<c>69</c>		<xref target="err_CB_PATH_DOWN" format="default"/></td>
	<c><xref target="err_DQUOT" /></c>		</tr>
			<tr>
	<c>NFS4ERR_ENCR_ALG_UNSUPP</c>		<td align="left">NFS4ERR_CLID_INUSE</td>
	<c>10079</c>		<td align="left">10017</td>
	<c><xref target="err_ENCR_ALG_UNSUPP" /></c>		<td align="left">
			<xref target="err_CLID_INUSE" format="default"/></td>
	<c>NFS4ERR_EXIST</c>		</tr>
	<c>17</c>		<tr>
	<c><xref target="err_EXIST" /></c>		<td align="left">NFS4ERR_CLIENTID_BUSY</td>
			<td align="left">10074</td>
	<c>NFS4ERR_EXPIRED</c>		<td align="left">
	<c>10011</c>		<xref target="err_CLIENTID_BUSY" format="default"/></td>
	<c><xref target="err_EXPIRED" /></c>		</tr>
			<tr>
	<c>NFS4ERR_FBIG</c>		<td align="left">NFS4ERR_COMPLETE_ALREADY</td>
	<c>27</c>		<td align="left">10054</td>
	<c><xref target="err_FBIG" /></c>		<td align="left">
			<xref target="err_COMPLETE_ALREADY" format="default"/></td>
	<c>NFS4ERR_FHEXPIRED</c>		</tr>
	<c>10014</c>		<tr>
	<c><xref target="err_FHEXPIRED" /></c>		<td align="left">NFS4ERR_CONN_NOT_BOUND_TO_SESSION</td>
			<td align="left">10055</td>
	<c>NFS4ERR_FILE_OPEN</c>		<td align="left">
	<c>10046</c>		<xref target="err_CONN_NOT_BOUND_TO_SESSION" format="default"/><
	<c><xref target="err_FILE_OPEN" /></c>		/td>
			</tr>
	<c>NFS4ERR_GRACE</c>		<tr>
	<c>10013</c>		<td align="left">NFS4ERR_DEADLOCK</td>
	<c><xref target="err_GRACE" /></c>		<td align="left">10045</td>
			<td align="left">
	<c>NFS4ERR_HASH_ALG_UNSUPP</c>		<xref target="err_DEADLOCK" format="default"/></td>
	<c>10072</c>		</tr>
	<c><xref target="err_HASH_ALG_UNSUPP" /></c>		<tr>
			<td align="left">NFS4ERR_DEADSESSION</td>
	<c>NFS4ERR_INVAL</c>		<td align="left">10078</td>
	<c>22</c>		<td align="left">
	<c><xref target="err_INVAL" /></c>		<xref target="err_DEADSESSION" format="default"/></td>
			</tr>
	<c>NFS4ERR_IO</c>		<tr>
	<c>5</c>		<td align="left">NFS4ERR_DELAY</td>
	<c><xref target="err_IO" /></c>		<td align="left">10008</td>
			<td align="left">
	<c>NFS4ERR_ISDIR</c>		<xref target="err_DELAY" format="default"/></td>
	<c>21</c>		</tr>
	<c><xref target="err_ISDIR" /></c>		<tr>
			<td align="left">NFS4ERR_DELEG_ALREADY_WANTED</td>
	<c>NFS4ERR_LAYOUTTRYLATER</c>		<td align="left">10056</td>
	<c>10058</c>		<td align="left">
	<c><xref target="err_LAYOUTTRYLATER" /></c>		<xref target="err_DELEG_ALREADY_WANTED" format="default"/></td>
			</tr>
	<c>NFS4ERR_LAYOUTUNAVAILABLE</c>		<tr>
	<c>10059</c>		<td align="left">NFS4ERR_DELEG_REVOKED</td>
	<c><xref target="err_LAYOUTUNAVAILABLE" /></c>		<td align="left">10087</td>
			<td align="left">
	<c>NFS4ERR_LEASE_MOVED</c>		<xref target="err_DELEG_REVOKED" format="default"/></td>
	<c>10031</c>		</tr>
	<c><xref target="err_LEASE_MOVED" /></c>		<tr>
			<td align="left">NFS4ERR_DENIED</td>
	<c>NFS4ERR_LOCKED</c>		<td align="left">10010</td>
	<c>10012</c>		<td align="left">
	<c><xref target="err_LOCKED" /></c>		<xref target="err_DENIED" format="default"/></td>
			</tr>
	<c>NFS4ERR_LOCKS_HELD</c>		<tr>
	<c>10037</c>		<td align="left">NFS4ERR_DIRDELEG_UNAVAIL</td>
	<c><xref target="err_LOCKS_HELD" /></c>		<td align="left">10084</td>
			<td align="left">
	<c>NFS4ERR_LOCK_NOTSUPP</c>		<xref target="err_DIRDELEG_UNAVAIL" format="default"/></td>
	<c>10043</c>		</tr>
	<c><xref target="err_LOCK_NOTSUPP" /></c>		<tr>
			<td align="left">NFS4ERR_DQUOT</td>
	<c>NFS4ERR_LOCK_RANGE</c>		<td align="left">69</td>
	<c>10028</c>		<td align="left">
	<c><xref target="err_LOCK_RANGE" /></c>		<xref target="err_DQUOT" format="default"/></td>
			</tr>
	<c>NFS4ERR_MINOR_VERS_MISMATCH</c>		<tr>
	<c>10021</c>		<td align="left">NFS4ERR_ENCR_ALG_UNSUPP</td>
	<c><xref target="err_MINOR_VERS_MISMATCH" /></c>		<td align="left">10079</td>
			<td align="left">
	<c>NFS4ERR_MLINK</c>		<xref target="err_ENCR_ALG_UNSUPP" format="default"/></td>
	<c>31</c>		</tr>
	<c><xref target="err_MLINK" /></c>		<tr>
			<td align="left">NFS4ERR_EXIST</td>
	<c>NFS4ERR_MOVED</c>		<td align="left">17</td>
	<c>10019</c>		<td align="left">
	<c><xref target="err_MOVED" /></c>		<xref target="err_EXIST" format="default"/></td>
			</tr>
	<c>NFS4ERR_NAMETOOLONG</c>		<tr>
	<c>63</c>		<td align="left">NFS4ERR_EXPIRED</td>
	<c><xref target="err_NAMETOOLONG" /></c>		<td align="left">10011</td>
			<td align="left">
	<c>NFS4ERR_NOENT</c>		<xref target="err_EXPIRED" format="default"/></td>
	<c>2</c>		</tr>
	<c><xref target="err_NOENT" /></c>		<tr>
			<td align="left">NFS4ERR_FBIG</td>
	<c>NFS4ERR_NOFILEHANDLE</c>		<td align="left">27</td>
	<c>10020</c>		<td align="left">
	<c><xref target="err_NOFILEHANDLE" /></c>		<xref target="err_FBIG" format="default"/></td>
			</tr>
	<c>NFS4ERR_NOMATCHING_LAYOUT</c>		<tr>
	<c>10060</c>		<td align="left">NFS4ERR_FHEXPIRED</td>
	<c><xref target="err_NOMATCHING_LAYOUT" /></c>		<td align="left">10014</td>
			<td align="left">
	<c>NFS4ERR_NOSPC</c>		<xref target="err_FHEXPIRED" format="default"/></td>
	<c>28</c>		</tr>
	<c><xref target="err_NOSPC" /></c>		<tr>
			<td align="left">NFS4ERR_FILE_OPEN</td>
	<c>NFS4ERR_NOTDIR</c>		<td align="left">10046</td>
	<c>20</c>		<td align="left">
	<c><xref target="err_NOTDIR" /></c>		<xref target="err_FILE_OPEN" format="default"/></td>
			</tr>
	<c>NFS4ERR_NOTEMPTY</c>		<tr>
	<c>66</c>		<td align="left">NFS4ERR_GRACE</td>
	<c><xref target="err_NOTEMPTY" /></c>		<td align="left">10013</td>
			<td align="left">
	<c>NFS4ERR_NOTSUPP</c>		<xref target="err_GRACE" format="default"/></td>
	<c>10004</c>		</tr>
	<c><xref target="err_NOTSUPP" /></c>		<tr>
			<td align="left">NFS4ERR_HASH_ALG_UNSUPP</td>
	<c>NFS4ERR_NOT_ONLY_OP</c>		<td align="left">10072</td>
	<c>10081</c>		<td align="left">
	<c><xref target="err_NOT_ONLY_OP" /></c>		<xref target="err_HASH_ALG_UNSUPP" format="default"/></td>
			</tr>
	<c>NFS4ERR_NOT_SAME</c>		<tr>
	<c>10027</c>		<td align="left">NFS4ERR_INVAL</td>
	<c><xref target="err_NOT_SAME" /></c>		<td align="left">22</td>
			<td align="left">
	<c>NFS4ERR_NO_GRACE</c>		<xref target="err_INVAL" format="default"/></td>
	<c>10033</c>		</tr>
	<c><xref target="err_NO_GRACE" /></c>		<tr>
			<td align="left">NFS4ERR_IO</td>
	<c>NFS4ERR_NXIO</c>		<td align="left">5</td>
	<c>6</c>		<td align="left">
	<c><xref target="err_NXIO" /></c>		<xref target="err_IO" format="default"/></td>
			</tr>
	<c>NFS4ERR_OLD_STATEID</c>		<tr>
	<c>10024</c>		<td align="left">NFS4ERR_ISDIR</td>
	<c><xref target="err_OLD_STATEID" /></c>		<td align="left">21</td>
			<td align="left">
	<c>NFS4ERR_OPENMODE</c>		<xref target="err_ISDIR" format="default"/></td>
	<c>10038</c>		</tr>
	<c><xref target="err_OPENMODE" /></c>		<tr>
			<td align="left">NFS4ERR_LAYOUTTRYLATER</td>
	<c>NFS4ERR_OP_ILLEGAL</c>		<td align="left">10058</td>
	<c>10044</c>		<td align="left">
	<c><xref target="err_OP_ILLEGAL" /></c>		<xref target="err_LAYOUTTRYLATER" format="default"/></td>
			</tr>
	<c>NFS4ERR_OP_NOT_IN_SESSION</c>		<tr>
	<c>10071</c>		<td align="left">NFS4ERR_LAYOUTUNAVAILABLE</td>
	<c><xref target="err_OP_NOT_IN_SESSION" /></c>		<td align="left">10059</td>
			<td align="left">
	<c>NFS4ERR_PERM</c>		<xref target="err_LAYOUTUNAVAILABLE" format="default"/></td>
	<c>1</c>		</tr>
	<c><xref target="err_PERM" /></c>		<tr>
			<td align="left">NFS4ERR_LEASE_MOVED</td>
	<c>NFS4ERR_PNFS_IO_HOLE</c>		<td align="left">10031</td>
	<c>10075</c>		<td align="left">
	<c><xref target="err_PNFS_IO_HOLE" /></c>		<xref target="err_LEASE_MOVED" format="default"/></td>
			</tr>
	<c>NFS4ERR_PNFS_NO_LAYOUT</c>		<tr>
	<c>10080</c>		<td align="left">NFS4ERR_LOCKED</td>
	<c><xref target="err_PNFS_NO_LAYOUT" /></c>		<td align="left">10012</td>
			<td align="left">
	<c>NFS4ERR_RECALLCONFLICT</c>		<xref target="err_LOCKED" format="default"/></td>
	<c>10061</c>		</tr>
	<c><xref target="err_RECALLCONFLICT" /></c>		<tr>
			<td align="left">NFS4ERR_LOCKS_HELD</td>
	<c>NFS4ERR_RECLAIM_BAD</c>		<td align="left">10037</td>
	<c>10034</c>		<td align="left">
	<c><xref target="err_RECLAIM_BAD" /></c>		<xref target="err_LOCKS_HELD" format="default"/></td>
			</tr>
	<c>NFS4ERR_RECLAIM_CONFLICT</c>		<tr>
	<c>10035</c>		<td align="left">NFS4ERR_LOCK_NOTSUPP</td>
	<c><xref target="err_RECLAIM_CONFLICT" /></c>		<td align="left">10043</td>
			<td align="left">
	<c>NFS4ERR_REJECT_DELEG</c>		<xref target="err_LOCK_NOTSUPP" format="default"/></td>
	<c>10085</c>		</tr>
	<c><xref target="err_REJECT_DELEG" /></c>		<tr>
			<td align="left">NFS4ERR_LOCK_RANGE</td>
	<c>NFS4ERR_REP_TOO_BIG</c>		<td align="left">10028</td>
	<c>10066</c>		<td align="left">
	<c><xref target="err_REP_TOO_BIG" /></c>		<xref target="err_LOCK_RANGE" format="default"/></td>
			</tr>
	<c>NFS4ERR_REP_TOO_BIG_TO_CACHE</c>		<tr>
	<c>10067</c>		<td align="left">NFS4ERR_MINOR_VERS_MISMATCH</td>
	<c><xref target="err_REP_TOO_BIG_TO_CACHE" /></c>		<td align="left">10021</td>
			<td align="left">
	<c>NFS4ERR_REQ_TOO_BIG</c>		<xref target="err_MINOR_VERS_MISMATCH" format="default"/></td>
	<c>10065</c>		</tr>
	<c><xref target="err_REQ_TOO_BIG" /></c>		<tr>
			<td align="left">NFS4ERR_MLINK</td>
	<c>NFS4ERR_RESTOREFH</c>		<td align="left">31</td>
	<c>10030</c>		<td align="left">
	<c><xref target="err_RESTOREFH" /></c>		<xref target="err_MLINK" format="default"/></td>
			</tr>
	<c>NFS4ERR_RETRY_UNCACHED_REP</c>		<tr>
	<c>10068</c>		<td align="left">NFS4ERR_MOVED</td>
	<c><xref target="err_RETRY_UNCACHED_REP" /></c>		<td align="left">10019</td>
			<td align="left">
	<c>NFS4ERR_RETURNCONFLICT</c>		<xref target="err_MOVED" format="default"/></td>
	<c>10086</c>		</tr>
	<c><xref target="err_RETURNCONFLICT" /></c>		<tr>
			<td align="left">NFS4ERR_NAMETOOLONG</td>
	<c>NFS4ERR_ROFS</c>		<td align="left">63</td>
	<c>30</c>		<td align="left">
	<c><xref target="err_ROFS" /></c>		<xref target="err_NAMETOOLONG" format="default"/></td>
			</tr>
	<c>NFS4ERR_SAME</c>		<tr>
	<c>10009</c>		<td align="left">NFS4ERR_NOENT</td>
	<c><xref target="err_SAME" /></c>		<td align="left">2</td>
			<td align="left">
	<c>NFS4ERR_SHARE_DENIED</c>		<xref target="err_NOENT" format="default"/></td>
	<c>10015</c>		</tr>
	<c><xref target="err_SHARE_DENIED" /></c>		<tr>
			<td align="left">NFS4ERR_NOFILEHANDLE</td>
	<c>NFS4ERR_SEQUENCE_POS</c>		<td align="left">10020</td>
	<c>10064</c>		<td align="left">
	<c><xref target="err_SEQUENCE_POS" /></c>		<xref target="err_NOFILEHANDLE" format="default"/></td>
			</tr>
	<c>NFS4ERR_SEQ_FALSE_RETRY</c>		<tr>
	<c>10076</c>		<td align="left">NFS4ERR_NOMATCHING_LAYOUT</td>
	<c><xref target="err_SEQ_FALSE_RETRY" /></c>		<td align="left">10060</td>
			<td align="left">
	<c>NFS4ERR_SEQ_MISORDERED</c>		<xref target="err_NOMATCHING_LAYOUT" format="default"/></td>
	<c>10063</c>		</tr>
	<c><xref target="err_SEQ_MISORDERED" /></c>		<tr>
			<td align="left">NFS4ERR_NOSPC</td>
	<c>NFS4ERR_SERVERFAULT</c>		<td align="left">28</td>
	<c>10006</c>		<td align="left">
	<c><xref target="err_SERVERFAULT" /></c>		<xref target="err_NOSPC" format="default"/></td>
			</tr>
	<c>NFS4ERR_STALE</c>		<tr>
	<c>70</c>		<td align="left">NFS4ERR_NOTDIR</td>
	<c><xref target="err_STALE" /></c>		<td align="left">20</td>
			<td align="left">
	<c>NFS4ERR_STALE_CLIENTID</c>		<xref target="err_NOTDIR" format="default"/></td>
	<c>10022</c>		</tr>
	<c><xref target="err_STALE_CLIENTID" /></c>		<tr>
			<td align="left">NFS4ERR_NOTEMPTY</td>
	<c>NFS4ERR_STALE_STATEID</c>		<td align="left">66</td>
	<c>10023</c>		<td align="left">
	<c><xref target="err_STALE_STATEID" /></c>		<xref target="err_NOTEMPTY" format="default"/></td>
			</tr>
	<c>NFS4ERR_SYMLINK</c>		<tr>
	<c>10029</c>		<td align="left">NFS4ERR_NOTSUPP</td>
	<c><xref target="err_SYMLINK" /></c>		<td align="left">10004</td>
			<td align="left">
	<c>NFS4ERR_TOOSMALL</c>		<xref target="err_NOTSUPP" format="default"/></td>
	<c>10005</c>		</tr>
	<c><xref target="err_TOOSMALL" /></c>		<tr>
			<td align="left">NFS4ERR_NOT_ONLY_OP</td>
	<c>NFS4ERR_TOO_MANY_OPS</c>		<td align="left">10081</td>
	<c>10070</c>		<td align="left">
	<c><xref target="err_TOO_MANY_OPS" /></c>		<xref target="err_NOT_ONLY_OP" format="default"/></td>
			</tr>
	<c>NFS4ERR_UNKNOWN_LAYOUTTYPE</c>		<tr>
	<c>10062</c>		<td align="left">NFS4ERR_NOT_SAME</td>
	<c><xref target="err_UNKNOWN_LAYOUTTYPE" /></c>		<td align="left">10027</td>
			<td align="left">
	<c>NFS4ERR_UNSAFE_COMPOUND</c>		<xref target="err_NOT_SAME" format="default"/></td>
	<c>10069</c>		</tr>
	<c><xref target="err_UNSAFE_COMPOUND" /></c>		<tr>
			<td align="left">NFS4ERR_NO_GRACE</td>
	<c>NFS4ERR_WRONGSEC</c>		<td align="left">10033</td>
	<c>10016</c>		<td align="left">
	<c><xref target="err_WRONGSEC" /></c>		<xref target="err_NO_GRACE" format="default"/></td>
			</tr>
	<c>NFS4ERR_WRONG_CRED</c>		<tr>
	<c>10082</c>		<td align="left">NFS4ERR_NXIO</td>
	<c><xref target="err_WRONG_CRED" /></c>		<td align="left">6</td>
			<td align="left">
	<c>NFS4ERR_WRONG_TYPE</c>		<xref target="err_NXIO" format="default"/></td>
	<c>10083</c>		</tr>
	<c><xref target="err_WRONG_TYPE" /></c>		<tr>
			<td align="left">NFS4ERR_OLD_STATEID</td>
	<c>NFS4ERR_XDEV</c>		<td align="left">10024</td>
	<c>18</c>		<td align="left">
	<c><xref target="err_XDEV" /></c>		<xref target="err_OLD_STATEID" format="default"/></td>
			</tr>
	</texttable>		<tr>
	<section title="General Errors" anchor="errors_gen">		<td align="left">NFS4ERR_OPENMODE</td>
	<t>		<td align="left">10038</td>
			<td align="left">
			<xref target="err_OPENMODE" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_OP_ILLEGAL</td>
			<td align="left">10044</td>
			<td align="left">
			<xref target="err_OP_ILLEGAL" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_OP_NOT_IN_SESSION</td>
			<td align="left">10071</td>
			<td align="left">
			<xref target="err_OP_NOT_IN_SESSION" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_PERM</td>
			<td align="left">1</td>
			<td align="left">
			<xref target="err_PERM" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_PNFS_IO_HOLE</td>
			<td align="left">10075</td>
			<td align="left">
			<xref target="err_PNFS_IO_HOLE" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_PNFS_NO_LAYOUT</td>
			<td align="left">10080</td>
			<td align="left">
			<xref target="err_PNFS_NO_LAYOUT" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_RECALLCONFLICT</td>
			<td align="left">10061</td>
			<td align="left">
			<xref target="err_RECALLCONFLICT" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_RECLAIM_BAD</td>
			<td align="left">10034</td>
			<td align="left">
			<xref target="err_RECLAIM_BAD" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_RECLAIM_CONFLICT</td>
			<td align="left">10035</td>
			<td align="left">
			<xref target="err_RECLAIM_CONFLICT" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_REJECT_DELEG</td>
			<td align="left">10085</td>
			<td align="left">
			<xref target="err_REJECT_DELEG" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_REP_TOO_BIG</td>
			<td align="left">10066</td>
			<td align="left">
			<xref target="err_REP_TOO_BIG" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_REP_TOO_BIG_TO_CACHE</td>
			<td align="left">10067</td>
			<td align="left">
			<xref target="err_REP_TOO_BIG_TO_CACHE" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_REQ_TOO_BIG</td>
			<td align="left">10065</td>
			<td align="left">
			<xref target="err_REQ_TOO_BIG" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_RESTOREFH</td>
			<td align="left">10030</td>
			<td align="left">
			<xref target="err_RESTOREFH" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_RETRY_UNCACHED_REP</td>
			<td align="left">10068</td>
			<td align="left">
			<xref target="err_RETRY_UNCACHED_REP" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_RETURNCONFLICT</td>
			<td align="left">10086</td>
			<td align="left">
			<xref target="err_RETURNCONFLICT" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_ROFS</td>
			<td align="left">30</td>
			<td align="left">
			<xref target="err_ROFS" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_SAME</td>
			<td align="left">10009</td>
			<td align="left">
			<xref target="err_SAME" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_SHARE_DENIED</td>
			<td align="left">10015</td>
			<td align="left">
			<xref target="err_SHARE_DENIED" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_SEQUENCE_POS</td>
			<td align="left">10064</td>
			<td align="left">
			<xref target="err_SEQUENCE_POS" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_SEQ_FALSE_RETRY</td>
			<td align="left">10076</td>
			<td align="left">
			<xref target="err_SEQ_FALSE_RETRY" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_SEQ_MISORDERED</td>
			<td align="left">10063</td>
			<td align="left">
			<xref target="err_SEQ_MISORDERED" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_SERVERFAULT</td>
			<td align="left">10006</td>
			<td align="left">
			<xref target="err_SERVERFAULT" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_STALE</td>
			<td align="left">70</td>
			<td align="left">
			<xref target="err_STALE" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_STALE_CLIENTID</td>
			<td align="left">10022</td>
			<td align="left">
			<xref target="err_STALE_CLIENTID" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_STALE_STATEID</td>
			<td align="left">10023</td>
			<td align="left">
			<xref target="err_STALE_STATEID" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_SYMLINK</td>
			<td align="left">10029</td>
			<td align="left">
			<xref target="err_SYMLINK" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_TOOSMALL</td>
			<td align="left">10005</td>
			<td align="left">
			<xref target="err_TOOSMALL" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_TOO_MANY_OPS</td>
			<td align="left">10070</td>
			<td align="left">
			<xref target="err_TOO_MANY_OPS" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_UNKNOWN_LAYOUTTYPE</td>
			<td align="left">10062</td>
			<td align="left">
			<xref target="err_UNKNOWN_LAYOUTTYPE" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_UNSAFE_COMPOUND</td>
			<td align="left">10069</td>
			<td align="left">
			<xref target="err_UNSAFE_COMPOUND" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_WRONGSEC</td>
			<td align="left">10016</td>
			<td align="left">
			<xref target="err_WRONGSEC" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_WRONG_CRED</td>
			<td align="left">10082</td>
			<td align="left">
			<xref target="err_WRONG_CRED" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_WRONG_TYPE</td>
			<td align="left">10083</td>
			<td align="left">
			<xref target="err_WRONG_TYPE" format="default"/></td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_XDEV</td>
			<td align="left">18</td>
			<td align="left">
			<xref target="err_XDEV" format="default"/></td>
			</tr>
			</tbody>
			</table>
			<section anchor="errors_gen" numbered="true" toc="default">
			<name>General Errors</name>
			<t>
	This section deals with errors that are applicable to a broad		This section deals with errors that are applicable to a broad
	set of different purposes.		set of different purposes.
	</t>		</t>
	<section title="NFS4ERR_BADXDR (Error Code 10036)"		<section anchor="err_BADXDR" numbered="true" toc="default">
	anchor="err_BADXDR">		<name>NFS4ERR_BADXDR (Error Code 10036)</name>
	<t>		<t>
	The arguments for this operation do not match those specified in		The arguments for this operation do not match those specified in
	the XDR definition. This includes situations in which the		the XDR definition. This includes situations in which the
	request ends before all the arguments have been seen. Note		request ends before all the arguments have been seen. Note
	that this error applies when fixed enumerations (these include		that this error applies when fixed enumerations (these include
	booleans) have a value within the input stream that is not		booleans) have a value within the input stream that is not
	valid for the enum. A replier may pre-parse all operations for		valid for the enum. A replier may pre-parse all operations for
	a Compound procedure before doing any operation execution		a Compound procedure before doing any operation execution
	and return RPC-level XDR errors in that case.		and return RPC-level XDR errors in that case.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_BAD_COOKIE (Error Code 10003)"		<section anchor="err_BAD_COOKIE" numbered="true" toc="default">
	anchor="err_BAD_COOKIE">		<name>NFS4ERR_BAD_COOKIE (Error Code 10003)</name>
	<t>		<t>
	Used for operations that provide a set of information indexed by		Used for operations that provide a set of information indexed by
	some quantity provided by the client or cookie sent by the		some quantity provided by the client or cookie sent by the
	server for an earlier invocation. Where the value cannot		server for an earlier invocation. Where the value cannot
	be used for its intended purpose, this error results.		be used for its intended purpose, this error results.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_DELAY (Error Code 10008)"		<section anchor="err_DELAY" numbered="true" toc="default">
	anchor="err_DELAY">		<name>NFS4ERR_DELAY (Error Code 10008)</name>
	<t>		<t>
	For any of a number of reasons, the replier could not		For any of a number of reasons, the replier could not
	process this operation in what was deemed a reasonable		process this operation in what was deemed a reasonable
	time. The client should wait and then try the request		time. The client should wait and then try the request
	with a new slot and sequence value.		with a new slot and sequence value.
	</t>		</t>
	<t>
	Some examples of scenarios that might lead to this situation:
	<list style="symbols">
	<t>		<t>
			Some examples of scenarios that might lead to this situation:
			</t>
			<ul spacing="normal">
			<li>
	A server that supports hierarchical storage receives a		A server that supports hierarchical storage receives a
	request to process a file that had been migrated.		request to process a file that had been migrated.
	</t>		</li>
	<t>		<li>
	An operation requires a delegation recall to proceed,		An operation requires a delegation recall to proceed,
	so that the need to wait for this delegation to be recalled		but the need to wait for this delegation to be recalled
	and returned makes processing		and returned makes processing this request in a timely fashion impo
	this request in a timely fashion impossible.		ssible.
	</t>		</li>
	<t>		<li>
	A request is being performed on a session being migrated		A request is being performed on a session being migrated
	from another server as described		from another server as described in <xref target="SEC11-XS-session"
	in <xref target="SEC11-XS-session"/>, and the lack		format="default"/>,
	of full information about the		and the lack of full information about the
	state of the session on the source makes it impossible		state of the session on the source makes it impossible
	to process the request immediately.		to process the request immediately.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	In such cases, returning the error NFS4ERR_DELAY allows		In such cases, returning the error NFS4ERR_DELAY allows
	necessary preparatory operations to proceed without		necessary preparatory operations to proceed without
	holding up requester resources such as a session slot.		holding up requester resources such as a session slot.
	After delaying for period of time, the client can		After delaying for period of time, the client can
	then re-send the operation in question, often as part		then re-send the operation in question, often as part
	of a nearly identical request. Because of the need to avoid		of a nearly identical request. Because of the need to avoid
	spurious reissues of non-idempotent operations and to avoid		spurious reissues of non-idempotent operations and to avoid
	acting in response to NFS4ERR_DELAY errors returned on responses		acting in response to NFS4ERR_DELAY errors returned on responses
	returned from the replier's replay cache,		returned from the replier's reply cache,
	integration with the session-provided replay cache is necessary.		integration with the session-provided reply cache is necessary.
	There are a number of cases to deal with, each of which requires		There are a number of cases to deal with, each of which requires
	different sorts of handling by the requester and replier:		different sorts of handling by the requester and replier:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	If NFS4ERR_DELAY is returned on a SEQUENCE operation, the		If NFS4ERR_DELAY is returned on a SEQUENCE operation, the
	request is retried in full with the SEQUENCE operation		request is retried in full with the SEQUENCE operation
	containing the same slot and sequence values. In this case,		containing the same slot and sequence values. In this case,
	the replier MUST avoid returning a response containing		the replier <bcp14>MUST</bcp14> avoid returning a response
	NFS4ERR_DELAY as the response to SEQUENCE solely on the basis		containing NFS4ERR_DELAY as the response to SEQUENCE solely
	of its presence in the replay cache. If the replier did this,		because an earlier instance of the same request returned that error
			and it was stored in the reply cache. If the replier did this,
	the retries would not be effective as there would be no		the retries would not be effective as there would be no
	opportunity for the replier to see whether the condition that		opportunity for the replier to see whether the condition that
	generated the NFS4ERR_DELAY had been rectified during the		generated the NFS4ERR_DELAY had been rectified during the
	interim between the original request and the retry.		interim between the original request and the retry.
	</t>		</li>
	<t>		<li>
	If NFS4ERR_DELAY is returned on an operation other than SEQUENCE		If NFS4ERR_DELAY is returned on an operation other than SEQUENCE
	which validly appears as the first operation of a request, handling		that validly appears as the first operation of a request, the handling
	is similar. The request can be retried in full without modification.		is similar. The request can be retried in full without modification.
	In this case as well,		In this case as well,
	the replier MUST avoid returning a response containing		the replier <bcp14>MUST</bcp14> avoid returning a response containing
	NFS4ERR_DELAY as the response to an initial operation of a request		NFS4ERR_DELAY as the response to an initial operation of a request
	solely on the basis		solely on the basis
	of its presence in the replay cache. If the replier did this,		of its presence in the reply cache. If the replier did this,
	the retries would not be effective as there would be no		the retries would not be effective as there would be no
	opportunity for the replier to see whether the condition that		opportunity for the replier to see whether the condition that
	generated the NFS4ERR_DELAY had been rectified during the		generated the NFS4ERR_DELAY had been rectified during the
	interim between the original request and the retry.		interim between the original request and the retry.
	</t>		</li>
	<t>		<li>
	If NFS4ERR_DELAY is returned on an operation other than the first		If NFS4ERR_DELAY is returned on an operation other than the first
	in the request, the request when retried MUST contain a SEQUENCE		in the request, the request when retried <bcp14>MUST</bcp14> contain a
	operation which is different		SEQUENCE
	than the original one, with either the bin id or the sequence value		operation that is different than the original one, with either
	different from that in the original request.		the slot ID or the sequence value different from that in the original
	Because requesters do this, there is no need for the		request. Because requesters do this, there is no need for the
	replier to take special care to avoid returning an		replier to take special care to avoid returning an
	NFS4ERR_DELAY error,		NFS4ERR_DELAY error obtained from the reply cache. When no non-idempot
	obtained from the replay cache. When no non-idempotent		ent
	operations have been processed before the NFS4ERR_DELAY was returned,		operations have been processed before the NFS4ERR_DELAY was returned,
	the requester should retry the request in full, with the only		the requester should retry the request in full, with the only
	difference from the original request being the modification to the		difference from the original request being the modification to the
	slot id or sequence value in the reissued SEQUENCE operation.		slot ID or sequence value in the reissued SEQUENCE operation.
	</t>		</li>
	<t>		<li>
			<t>
	When NFS4ERR_DELAY is returned on an operation other than the first		When NFS4ERR_DELAY is returned on an operation other than the first
	within a request and there has been a non-idempotent operation		within a request and there has been a non-idempotent operation
	processed before the		processed before the NFS4ERR_DELAY was returned, reissuing the request
	NFS4ERR_DELAY was returned, reissuing the request as is normally		as is normally
	done would incorrectly cause the re-execution of the non-idempotent		done would incorrectly cause the re-execution of the non-idempotent ope
	operation.		ration.
	<vspace blankLines="1"/>		</t>
	To avoid this situation, the client should reissue the request		<t>
	without the		To avoid this situation, the client should reissue the request without
			the
	non-idempotent operation. The request still must use a SEQUENCE		non-idempotent operation. The request still must use a SEQUENCE
	operation with either a different slot id or sequence value from		operation with either a different slot ID or sequence value from
	the SEQUENCE in the original request. Because this is done, there		the SEQUENCE in the original request. Because this is done, there
	is no way the replier could avoid spuriously re-executing the		is no way the replier could avoid spuriously re-executing the
	non-idempotent operation since the different SEQUENCE parameters		non-idempotent operation since the different SEQUENCE parameters
	prevent the requester from recognizing that the non-idempotent		prevent the requester from recognizing that the non-idempotent
	operation is being retried.		operation is being retried.
	</t>		</t>
	</list>		</li>
	</t>		</ul>
			<t>
	<t>
	Note that without the ability to return NFS4ERR_DELAY and the		Note that without the ability to return NFS4ERR_DELAY and the
	requester's willingness to re-send when receiving it, deadlock might		requester's willingness to re-send when receiving it, deadlock might
	result. For example, if a recall is done, and if the delegation		result. For example, if a recall is done, and if the delegation
	return or		return or operations preparatory to delegation return are held up by
	operations preparatory to delegation return are held up by
	other operations that need the delegation to be returned,		other operations that need the delegation to be returned,
	session slots might not be available. The result could be		session slots might not be available. The result could be
	deadlock.		deadlock.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_INVAL (Error Code 22)"		<section anchor="err_INVAL" numbered="true" toc="default">
	anchor="err_INVAL">		<name>NFS4ERR_INVAL (Error Code 22)</name>
	<t>		<t>
	The arguments for this operation are not valid for some reason, even		The arguments for this operation are not valid for some reason, even
	though they do match those specified in the XDR definition for		though they do match those specified in the XDR definition for
	the request.		the request.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_NOTSUPP (Error Code 10004)"		<section anchor="err_NOTSUPP" numbered="true" toc="default">
	anchor="err_NOTSUPP">		<name>NFS4ERR_NOTSUPP (Error Code 10004)</name>
	<t>		<t>
	Operation not supported, either because the operation is		Operation not supported, either because the operation is
	an OPTIONAL one and is not supported by this server or		an <bcp14>OPTIONAL</bcp14> one and is not supported by this server or
	because the operation MUST NOT be implemented in		because the operation <bcp14>MUST NOT</bcp14> be implemented in
	the current minor version.		the current minor version.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_SERVERFAULT (Error Code 10006)"		<section anchor="err_SERVERFAULT" numbered="true" toc="default">
	anchor="err_SERVERFAULT">		<name>NFS4ERR_SERVERFAULT (Error Code 10006)</name>
	<t>		<t>
	An error occurred on the server that does not map to any of		An error occurred on the server that does not map to any of
	the specific legal NFSv4.1 protocol error values. The client		the specific legal NFSv4.1 protocol error values. The client
	should translate this into an appropriate error. UNIX clients		should translate this into an appropriate error. UNIX clients
	may choose to translate this to EIO.		may choose to translate this to EIO.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_TOOSMALL (Error Code 10005)"		<section anchor="err_TOOSMALL" numbered="true" toc="default">
	anchor="err_TOOSMALL">		<name>NFS4ERR_TOOSMALL (Error Code 10005)</name>
	<t>		<t>
	Used where an operation returns a variable amount of data,		Used where an operation returns a variable amount of data,
	with a limit specified by the client. Where the data		with a limit specified by the client. Where the data
	returned cannot be fit within the limit specified by the		returned cannot be fit within the limit specified by the
	client, this error results.		client, this error results.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_fh" numbered="true" toc="default">
	<section title="Filehandle Errors" anchor="errors_fh">		<name>Filehandle Errors</name>
	<t>		<t>
	These errors deal with the situation in which the current		These errors deal with the situation in which the current
	or saved filehandle, or the filehandle passed to PUTFH		or saved filehandle, or the filehandle passed to PUTFH
	intended to become the current filehandle, is invalid		intended to become the current filehandle, is invalid
	in some way. This includes situations in which the		in some way. This includes situations in which the
	filehandle is a valid filehandle in general but is not		filehandle is a valid filehandle in general but is not
	of the appropriate object type for the current operation.		of the appropriate object type for the current operation.
	</t>		</t>
	<t>		<t>
	Where the error description indicates a problem with the		Where the error description indicates a problem with the
	current or saved filehandle, it is to be understood that		current or saved filehandle, it is to be understood that
	filehandles are only checked for the condition if they		filehandles are only checked for the condition if they
	are implicit arguments of the operation in question.		are implicit arguments of the operation in question.
	</t>		</t>
	<section title="NFS4ERR_BADHANDLE (Error Code 10001)"		<section anchor="err_BADHANDLE" numbered="true" toc="default">
	anchor="err_BADHANDLE">		<name>NFS4ERR_BADHANDLE (Error Code 10001)</name>
	<t>		<t>
	Illegal NFS filehandle for the current server. The current		Illegal NFS filehandle for the current server. The current
	file handle failed internal consistency checks. Once accepted		filehandle failed internal consistency checks. Once accepted
	as valid (by PUTFH), no subsequent status change can cause the		as valid (by PUTFH), no subsequent status change can cause the
	filehandle to generate this error.		filehandle to generate this error.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_FHEXPIRED (Error Code 10014)"		<section anchor="err_FHEXPIRED" numbered="true" toc="default">
	anchor="err_FHEXPIRED">		<name>NFS4ERR_FHEXPIRED (Error Code 10014)</name>
	<t>		<t>
	A current or saved filehandle that is an argument to the		A current or saved filehandle that is an argument to the
	current operation is volatile and has expired at the server.		current operation is volatile and has expired at the server.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_ISDIR (Error Code 21)"		<section anchor="err_ISDIR" numbered="true" toc="default">
	anchor="err_ISDIR">		<name>NFS4ERR_ISDIR (Error Code 21)</name>
	<t>		<t>
	The current or saved filehandle designates a directory		The current or saved filehandle designates a directory
	when the current operation does not allow a directory to		when the current operation does not allow a directory to
	be accepted as the target of this operation.		be accepted as the target of this operation.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_MOVED (Error Code 10019)"		<section anchor="err_MOVED" numbered="true" toc="default">
	anchor="err_MOVED">		<name>NFS4ERR_MOVED (Error Code 10019)</name>
	<t>		<t>
	The file system that contains the current filehandle object		The file system that contains the current filehandle object
	is not present at the server, or is not accessible using the		is not present at the server or is not accessible with the
	network address used. It may have been made accessible on a different		network address used. It may have been made accessible on a different
	set of network addresses, relocated or		set of network addresses, relocated or
	migrated to another server, or it may have never been present.		migrated to another server, or it may have never been present.
	The client may obtain the new file system location by obtaining		The client may obtain the new file system location by obtaining
	the "fs_locations" or "fs_locations_info" attribute for the		the fs_locations or fs_locations_info attribute for the
	current filehandle. For further discussion, refer to		current filehandle. For further discussion, refer to
	<xref target="presence_or_absence" />.		<xref target="presence_or_absence" format="default"/>.
	</t>		</t>
	<t>		<t>
	As with the case of NFS4ERR_DELAY, it is possible that one or		As with the case of NFS4ERR_DELAY, it is possible that one or
	more non-idempotent operations may have been successfully executed		more non-idempotent operations may have been successfully executed
	within a COMPOUND before NFS4ERR_MOVED is returned. Because of		within a COMPOUND before NFS4ERR_MOVED is returned. Because of
	this, once the new location is determined, the original request		this, once the new location is determined, the original request
	which received the NFS4ERR_MOVED should not be re-executed in full.		that received the NFS4ERR_MOVED should not be re-executed in full.
	Instead, the client should send a new COMPOUND, with any successfully		Instead, the client should send a new COMPOUND with any successfully
	executed non-idempotent		executed non-idempotent
	operations removed. When the client uses the same session for the		operations removed. When the client uses the same session for the
	new COMPOUND, its SEQUENCE operation should use a		new COMPOUND, its SEQUENCE operation should use a different slot ID or se
	different slot id or sequence.		quence.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_NOFILEHANDLE (Error Code 10020)"		<section anchor="err_NOFILEHANDLE" numbered="true" toc="default">
	anchor="err_NOFILEHANDLE">		<name>NFS4ERR_NOFILEHANDLE (Error Code 10020)</name>
	<t>		<t>
	The logical current or saved filehandle value is required by		The logical current or saved filehandle value is required by
	the current operation and is not set.		the current operation and is not set.
	This may be a result of a malformed COMPOUND		This may be a result of a malformed COMPOUND
	operation (i.e., no PUTFH or PUTROOTFH before an operation that		operation (i.e., no PUTFH or PUTROOTFH before an operation that
	requires the current filehandle be set).		requires the current filehandle be set).
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_NOTDIR (Error Code 20)"		<section anchor="err_NOTDIR" numbered="true" toc="default">
	anchor="err_NOTDIR">		<name>NFS4ERR_NOTDIR (Error Code 20)</name>
	<t>		<t>
	The current (or saved) filehandle designates an object that		The current (or saved) filehandle designates an object that
	is not a directory for an operation in which a directory is		is not a directory for an operation in which a directory is
	required.		required.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_STALE (Error Code 70)"		<section anchor="err_STALE" numbered="true" toc="default">
	anchor="err_STALE">		<name>NFS4ERR_STALE (Error Code 70)</name>
	<t>		<t>
	The current or saved filehandle value designating an argument		The current or saved filehandle value designating an argument
	to the current operation is invalid. The file referred to by		to the current operation is invalid. The file referred to by
	that filehandle no longer exists or access to it has been		that filehandle no longer exists or access to it has been
	revoked.		revoked.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_SYMLINK (Error Code 10029)"		<section anchor="err_SYMLINK" numbered="true" toc="default">
	anchor="err_SYMLINK">		<name>NFS4ERR_SYMLINK (Error Code 10029)</name>
	<t>		<t>
	The current filehandle designates a symbolic link when the		The current filehandle designates a symbolic link when the
	current operation does not allow a symbolic link as the		current operation does not allow a symbolic link as the
	target.		target.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_WRONG_TYPE (Error Code 10083)"		<section anchor="err_WRONG_TYPE" numbered="true" toc="default">
	anchor="err_WRONG_TYPE">		<name>NFS4ERR_WRONG_TYPE (Error Code 10083)</name>
	<t>		<t>
	The current (or saved) filehandle designates an object that		The current (or saved) filehandle designates an object that
	is of an invalid type for the current operation, and there is no		is of an invalid type for the current operation, and there is no
	more specific error (such as NFS4ERR_ISDIR or NFS4ERR_SYMLINK)		more specific error (such as NFS4ERR_ISDIR or NFS4ERR_SYMLINK)
	that applies. Note that in NFSv4.0, such situations generally		that applies. Note that in NFSv4.0, such situations generally
	resulted in the less-specific error NFS4ERR_INVAL.		resulted in the less-specific error NFS4ERR_INVAL.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_comp" numbered="true" toc="default">
	<section title="Compound Structure Errors" anchor="errors_comp">		<name>Compound Structure Errors</name>
	<t>		<t>
	This section deals with errors that relate to the overall structure		This section deals with errors that relate to the overall structure
	of a Compound request (by which we mean to include both		of a Compound request (by which we mean to include both
	COMPOUND and CB_COMPOUND), rather than to particular operations.		COMPOUND and CB_COMPOUND), rather than to particular operations.
	</t>		</t>
	<t>		<t>
	There are a number of basic constraints on the operations that		There are a number of basic constraints on the operations that
	may appear in a Compound request. Sessions add to these basic		may appear in a Compound request. Sessions add to these basic
	constraints by requiring a Sequence operation (either SEQUENCE		constraints by requiring a Sequence operation (either SEQUENCE
	or CB_SEQUENCE) at the start of the Compound.		or CB_SEQUENCE) at the start of the Compound.
	</t>		</t>
	<section title="NFS_OK (Error code 0)"		<section anchor="err_OK" numbered="true" toc="default">
	anchor="err_OK">		<name>NFS_OK (Error code 0)</name>
	<t>		<t>
	Indicates the operation completed successfully, in that all		Indicates the operation completed successfully, in that all
	of the constituent operations completed without error.		of the constituent operations completed without error.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_MINOR_VERS_MISMATCH (Error code 10021)"		<section anchor="err_MINOR_VERS_MISMATCH" numbered="true" toc="default
	anchor="err_MINOR_VERS_MISMATCH">		">
	<t>		<name>NFS4ERR_MINOR_VERS_MISMATCH (Error code 10021)</name>
			<t>
	The minor version specified is not one that the current listener		The minor version specified is not one that the current listener
	supports. This value is returned in the overall status for the		supports. This value is returned in the overall status for the
	Compound but is not associated with a specific operation since		Compound but is not associated with a specific operation since
	the results will specify a result count of zero.		the results will specify a result count of zero.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_NOT_ONLY_OP (Error Code 10081)"		<section anchor="err_NOT_ONLY_OP" numbered="true" toc="default">
	anchor="err_NOT_ONLY_OP">		<name>NFS4ERR_NOT_ONLY_OP (Error Code 10081)</name>
	<t>		<t>
	Certain operations, which are allowed to be executed outside		Certain operations, which are allowed to be executed outside
	of a session, MUST be the only operation within a Compound		of a session, <bcp14>MUST</bcp14> be the only operation within a Compoun d
	whenever the Compound does not start with a Sequence		whenever the Compound does not start with a Sequence
	operation. This error results when that constraint is not met.		operation. This error results when that constraint is not met.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_OP_ILLEGAL (Error Code 10044)"		<section anchor="err_OP_ILLEGAL" numbered="true" toc="default">
	anchor="err_OP_ILLEGAL">		<name>NFS4ERR_OP_ILLEGAL (Error Code 10044)</name>
	<t>		<t>
	The operation code is not a valid one for the current		The operation code is not a valid one for the current
	Compound procedure. The opcode		Compound procedure. The opcode
	in the result stream matched with this error is the		in the result stream matched with this error is the
	ILLEGAL value, although the value that appears in the		ILLEGAL value, although the value that appears in the
	request stream may be different. Where an illegal		request stream may be different. Where an illegal
	value appears and the replier pre-parses all operations for		value appears and the replier pre-parses all operations for
	a Compound procedure before doing any operation execution,		a Compound procedure before doing any operation execution,
	an RPC-level XDR error may be returned.		an RPC-level XDR error may be returned.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_OP_NOT_IN_SESSION (Error Code 10071)"		<section anchor="err_OP_NOT_IN_SESSION" numbered="true" toc="default">
	anchor="err_OP_NOT_IN_SESSION">		<name>NFS4ERR_OP_NOT_IN_SESSION (Error Code 10071)</name>
	<t>		<t>
	Most forward operations and all callback operations are only		Most forward operations and all callback operations are only
	valid within the context of a session, so that the Compound		valid within the context of a session, so that the Compound
	request in question MUST begin with a Sequence operation.		request in question <bcp14>MUST</bcp14> begin with a Sequence operation.
	If an attempt is made to execute these operations outside		If an attempt is made to execute these operations outside
	the context of session, this error results.		the context of session, this error results.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_REP_TOO_BIG (Error Code 10066)"		<section anchor="err_REP_TOO_BIG" numbered="true" toc="default">
	anchor="err_REP_TOO_BIG">		<name>NFS4ERR_REP_TOO_BIG (Error Code 10066)</name>
	<t>		<t>
	The reply to a Compound would exceed the		The reply to a Compound would exceed the
	channel's negotiated maximum response size.		channel's negotiated maximum response size.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_REP_TOO_BIG_TO_CACHE (Error Code 10067)"		<section anchor="err_REP_TOO_BIG_TO_CACHE" numbered="true" toc="defaul
	anchor="err_REP_TOO_BIG_TO_CACHE">		t">
	<t>		<name>NFS4ERR_REP_TOO_BIG_TO_CACHE (Error Code 10067)</name>
			<t>
	The reply to a Compound would exceed the		The reply to a Compound would exceed the
	channel's negotiated maximum size for replies cached in the		channel's negotiated maximum size for replies cached in the
	reply cache when the Sequence for the current request specifies		reply cache when the Sequence for the current request specifies
	that this request is to be cached.		that this request is to be cached.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_REQ_TOO_BIG (Error Code 10065)"		<section anchor="err_REQ_TOO_BIG" numbered="true" toc="default">
	anchor="err_REQ_TOO_BIG">		<name>NFS4ERR_REQ_TOO_BIG (Error Code 10065)</name>
	<t>		<t>
	The Compound request exceeds the		The Compound request exceeds the
	channel's negotiated maximum size for requests.		channel's negotiated maximum size for requests.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_RETRY_UNCACHED_REP (Error Code 10068)"		<section anchor="err_RETRY_UNCACHED_REP" numbered="true" toc="default"
	anchor="err_RETRY_UNCACHED_REP">		>
	<t>		<name>NFS4ERR_RETRY_UNCACHED_REP (Error Code 10068)</name>
			<t>
	The requester has attempted a retry of a Compound		The requester has attempted a retry of a Compound
	that it previously requested not		that it previously requested not
	be placed in the reply cache.		be placed in the reply cache.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_SEQUENCE_POS (Error Code 10064)"		<section anchor="err_SEQUENCE_POS" numbered="true" toc="default">
	anchor="err_SEQUENCE_POS">		<name>NFS4ERR_SEQUENCE_POS (Error Code 10064)</name>
	<t>		<t>
	A Sequence operation appeared in a		A Sequence operation appeared in a
	position other than the first operation of a		position other than the first operation of a
	Compound request.		Compound request.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_TOO_MANY_OPS (Error Code 10070)"		<section anchor="err_TOO_MANY_OPS" numbered="true" toc="default">
	anchor="err_TOO_MANY_OPS">		<name>NFS4ERR_TOO_MANY_OPS (Error Code 10070)</name>
	<t>		<t>
	The Compound request has too many operations, exceeding the		The Compound request has too many operations, exceeding the
	count negotiated when the session was created.		count negotiated when the session was created.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_UNSAFE_COMPOUND (Error Code 10068)"		<section anchor="err_UNSAFE_COMPOUND" numbered="true" toc="default">
	anchor="err_UNSAFE_COMPOUND">		<name>NFS4ERR_UNSAFE_COMPOUND (Error Code 10068)</name>
	<t>		<t>
	The client has sent a COMPOUND request with an unsafe		The client has sent a COMPOUND request with an unsafe
	mix of operations -- specifically, with a non-idempotent		mix of operations -- specifically, with a non-idempotent
	operation that changes the current filehandle and that is not followed b y a		operation that changes the current filehandle and that is not followed b y a
	GETFH.		GETFH.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_fs" numbered="true" toc="default">
	<section title="File System Errors" anchor="errors_fs">		<name>File System Errors</name>
	<t>		<t>
	These errors describe situations that occurred in the underlying		These errors describe situations that occurred in the underlying
	file system implementation rather than in the protocol or any		file system implementation rather than in the protocol or any
	NFSv4.x feature.		NFSv4.x feature.
	</t>		</t>
	<section title="NFS4ERR_BADTYPE (Error Code 10007)"		<section anchor="err_BADTYPE" numbered="true" toc="default">
	anchor="err_BADTYPE">		<name>NFS4ERR_BADTYPE (Error Code 10007)</name>
	<t>		<t>
	An attempt was made to create an object with an inappropriate		An attempt was made to create an object with an inappropriate
	type specified to CREATE. This may be because the type		type specified to CREATE. This may be because the type
	is undefined, because the type is not supported by the		is undefined, because the type is not supported by the
	server, or because the type is not intended to be created by CREATE		server, or because the type is not intended to be created by CREATE
	(such as a regular file or named attribute, for		(such as a regular file or named attribute, for
	which OPEN is used to do the file creation).		which OPEN is used to do the file creation).
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_DQUOT (Error Code 19)"		<section anchor="err_DQUOT" numbered="true" toc="default">
	anchor="err_DQUOT">		<name>NFS4ERR_DQUOT (Error Code 69)</name>
	<t>		<t>
	Resource (quota) hard limit exceeded. The user's resource		Resource (quota) hard limit exceeded. The user's resource
	limit on the server has been exceeded.		limit on the server has been exceeded.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_EXIST (Error Code 17)"		<section anchor="err_EXIST" numbered="true" toc="default">
	anchor="err_EXIST">		<name>NFS4ERR_EXIST (Error Code 17)</name>
	<t>		<t>
	A file of the specified target name (when creating, renaming,		A file of the specified target name (when creating, renaming,
	or linking) already exists.		or linking) already exists.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_FBIG (Error Code 27)"		<section anchor="err_FBIG" numbered="true" toc="default">
	anchor="err_FBIG">		<name>NFS4ERR_FBIG (Error Code 27)</name>
	<t>		<t>
	The file is too large. The operation would have caused the file to		The file is too large. The operation would have caused the file to
	grow beyond the server's limit.		grow beyond the server's limit.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_FILE_OPEN (Error Code 10046)"		<section anchor="err_FILE_OPEN" numbered="true" toc="default">
	anchor="err_FILE_OPEN">		<name>NFS4ERR_FILE_OPEN (Error Code 10046)</name>
	<t>		<t>
	The operation is not allowed because a		The operation is not allowed because a
	file involved in the operation is currently open.		file involved in the operation is currently open.
	Servers may, but are not required to, disallow linking-to,		Servers may, but are not required to, disallow linking-to,
	removing, or renaming open files.		removing, or renaming open files.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_IO (Error Code 5)"		<section anchor="err_IO" numbered="true" toc="default">
	anchor="err_IO">		<name>NFS4ERR_IO (Error Code 5)</name>
	<t>		<t>
	Indicates that an I/O error occurred for which the file system		Indicates that an I/O error occurred for which the file system
	was unable to provide recovery.		was unable to provide recovery.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_MLINK (Error Code 31)"		<section anchor="err_MLINK" numbered="true" toc="default">
	anchor="err_MLINK">		<name>NFS4ERR_MLINK (Error Code 31)</name>
	<t>		<t>
	The request would have caused the server's limit for the		The request would have caused the server's limit for the
	number of hard links a file may have to be exceeded.		number of hard links a file may have to be exceeded.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_NOENT (Error Code 2)"		<section anchor="err_NOENT" numbered="true" toc="default">
	anchor="err_NOENT">		<name>NFS4ERR_NOENT (Error Code 2)</name>
	<t>		<t>
	Indicates no such file or directory. The file or directory name		Indicates no such file or directory. The file or directory name
	specified does not exist.		specified does not exist.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_NOSPC (Error Code 28)"		<section anchor="err_NOSPC" numbered="true" toc="default">
	anchor="err_NOSPC">		<name>NFS4ERR_NOSPC (Error Code 28)</name>
	<t>		<t>
	Indicates there is no space left on the device. The operation would have		Indicates there is no space left on the device. The operation would have
	caused the server's file system to exceed its limit.		caused the server's file system to exceed its limit.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_NOTEMPTY (Error Code 66)"		<section anchor="err_NOTEMPTY" numbered="true" toc="default">
	anchor="err_NOTEMPTY">		<name>NFS4ERR_NOTEMPTY (Error Code 66)</name>
	<t>		<t>
	An attempt was made to remove a directory that was not		An attempt was made to remove a directory that was not
	empty.		empty.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_ROFS (Error Code 30)"		<section anchor="err_ROFS" numbered="true" toc="default">
	anchor="err_ROFS">		<name>NFS4ERR_ROFS (Error Code 30)</name>
	<t>		<t>
	Indicates a read-only file system. A modifying operation was		Indicates a read-only file system. A modifying operation was
	attempted on a read-only file system.		attempted on a read-only file system.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_XDEV (Error Code 18)"		<section anchor="err_XDEV" numbered="true" toc="default">
	anchor="err_XDEV">		<name>NFS4ERR_XDEV (Error Code 18)</name>
	<t>		<t>
	Indicates an attempt to do an operation, such as linking, that		Indicates an attempt to do an operation, such as linking, that
	inappropriately crosses a boundary. This may be due to such		inappropriately crosses a boundary. This may be due to such
	boundaries as:		boundaries as:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	that between file systems (where the fsids are different).		that between file systems (where the fsids are different).
	</t>		</li>
	<t>		<li>
	that between different named attribute directories or		that between different named attribute directories or
	between a named attribute directory and an ordinary		between a named attribute directory and an ordinary
	directory.		directory.
	</t>		</li>
	<t>		<li>
	that between byte-ranges of a file system that the file system		that between byte-ranges of a file system that the file system
	implementation treats as separate (for example, for space		implementation treats as separate (for example, for space
	accounting purposes), and where cross-connection between		accounting purposes), and where cross-connection between
	the byte-ranges are not allowed.		the byte-ranges are not allowed.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="errors_state_mgt" numbered="true" toc="default">
			<name>State Management Errors</name>
	<section title="State Management Errors" anchor="errors_state_mgt">		<t>
	<t>
	These errors indicate problems with the stateid (or one of		These errors indicate problems with the stateid (or one of
	the stateids) passed to a given operation.		the stateids) passed to a given operation.
	This includes		This includes
	situations in which the stateid is invalid as well as		situations in which the stateid is invalid as well as
	situations in which the stateid is valid but designates		situations in which the stateid is valid but designates
	locking state that has been revoked.		locking state that has been revoked.
	Depending on the operation, the		Depending on the operation, the
	stateid when valid may designate opens, byte-range locks,		stateid when valid may designate opens, byte-range locks,
	file or directory delegations, layouts, or device maps.		file or directory delegations, layouts, or device maps.
	</t>		</t>
	<section title="NFS4ERR_ADMIN_REVOKED (Error Code 10047)"		<section anchor="err_ADMIN_REVOKED" numbered="true" toc="default">
	anchor="err_ADMIN_REVOKED">		<name>NFS4ERR_ADMIN_REVOKED (Error Code 10047)</name>
	<t>		<t>
	A stateid designates locking state of any type that has		A stateid designates locking state of any type that has
	been revoked due to administrative interaction, possibly		been revoked due to administrative interaction, possibly
	while the lease is valid.		while the lease is valid.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_BAD_STATEID (Error Code 10026)"		<section anchor="err_BAD_STATEID" numbered="true" toc="default">
	anchor="err_BAD_STATEID">		<name>NFS4ERR_BAD_STATEID (Error Code 10026)</name>
	<t>		<t>
	A stateid does not properly designate any valid		A stateid does not properly designate any valid
	state. See Sections <xref target="stateid_lifetime" format="counter" />		state. See Sections <xref target="stateid_lifetime" format="counter"/>
	and		and
	<xref target="special_stateid" format="counter" />		<xref target="special_stateid" format="counter"/>
	for a discussion of how stateids are validated.		for a discussion of how stateids are validated.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_DELEG_REVOKED (Error Code 10087)"		<section anchor="err_DELEG_REVOKED" numbered="true" toc="default">
	anchor="err_DELEG_REVOKED">		<name>NFS4ERR_DELEG_REVOKED (Error Code 10087)</name>
	<t>		<t>
	A stateid designates recallable locking state of		A stateid designates recallable locking state of
	any type (delegation or layout) that has been		any type (delegation or layout) that has been
	revoked due to the failure of the client to return		revoked due to the failure of the client to return
	the lock when it was recalled.		the lock when it was recalled.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_EXPIRED (Error Code 10011)"		<section anchor="err_EXPIRED" numbered="true" toc="default">
	anchor="err_EXPIRED">		<name>NFS4ERR_EXPIRED (Error Code 10011)</name>
	<t>		<t>
	A stateid designates locking state of any type that has		A stateid designates locking state of any type that has
	been revoked due to expiration of the client's lease,		been revoked due to expiration of the client's lease,
	either immediately upon lease expiration, or following		either immediately upon lease expiration, or following
	a later request for a conflicting lock.		a later request for a conflicting lock.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_OLD_STATEID (Error Code 10024)"		<section anchor="err_OLD_STATEID" numbered="true" toc="default">
	anchor="err_OLD_STATEID">		<name>NFS4ERR_OLD_STATEID (Error Code 10024)</name>
	<t>		<t>
	A stateid with a non-zero seqid value does match		A stateid with a non-zero seqid value does match
	the current seqid for the state designated by the		the current seqid for the state designated by the
	user.		user.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_sec" numbered="true" toc="default">
	<section title="Security Errors" anchor="errors_sec">		<name>Security Errors</name>
	<t>		<t>
	These are the various permission-related errors in NFSv4.1.		These are the various permission-related errors in NFSv4.1.
	</t>		</t>
	<section title="NFS4ERR_ACCESS (Error Code 13)"		<section anchor="err_ACCESS" numbered="true" toc="default">
	anchor="err_ACCESS">		<name>NFS4ERR_ACCESS (Error Code 13)</name>
	<t>		<t>
	Indicates permission denied. The caller does		Indicates permission denied. The caller does
	not have the correct permission to perform		not have the correct permission to perform
	the requested operation. Contrast this with		the requested operation. Contrast this with
	NFS4ERR_PERM (<xref target="err_PERM" />), which		NFS4ERR_PERM (<xref target="err_PERM" format="default"/>), which
	restricts itself to owner or privileged-user		restricts itself to owner or privileged-user
	permission failures, and NFS4ERR_WRONG_CRED		permission failures, and NFS4ERR_WRONG_CRED
	(<xref target="err_WRONG_CRED" />), which deals		(<xref target="err_WRONG_CRED" format="default"/>), which deals
	with appropriate permission to delete or modify		with appropriate permission to delete or modify
	transient objects based on the credentials of		transient objects based on the credentials of
	the user that created them.		the user that created them.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_PERM (Error Code 1)"		<section anchor="err_PERM" numbered="true" toc="default">
	anchor="err_PERM">		<name>NFS4ERR_PERM (Error Code 1)</name>
	<t>		<t>
	Indicates requester is not the owner. The operation was not		Indicates requester is not the owner. The operation was not
	allowed because the caller is neither a privileged user		allowed because the caller is neither a privileged user
	(root) nor the owner of the target of the operation.		(root) nor the owner of the target of the operation.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_WRONGSEC (Error Code 10016)"		<section anchor="err_WRONGSEC" numbered="true" toc="default">
	anchor="err_WRONGSEC">		<name>NFS4ERR_WRONGSEC (Error Code 10016)</name>
	<t>		<t>
	Indicates that the security mechanism being used by the client		Indicates that the security mechanism being used by the client
	for the operation does not match the server's security policy.		for the operation does not match the server's security policy.
	The client should change the security mechanism being used and		The client should change the security mechanism being used and
	re-send the operation (but not with the same slot ID and		re-send the operation (but not with the same slot ID and
	sequence ID; one or both MUST be different on the re-send). SECINFO and SECINFO_NO_NAME can be used		sequence ID; one or both <bcp14>MUST</bcp14> be different on the re-send ). SECINFO and SECINFO_NO_NAME can be used
	to determine the appropriate mechanism.		to determine the appropriate mechanism.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_WRONG_CRED (Error Code 10082)"		<section anchor="err_WRONG_CRED" numbered="true" toc="default">
	anchor="err_WRONG_CRED">		<name>NFS4ERR_WRONG_CRED (Error Code 10082)</name>
	<t>		<t>
	An operation that manipulates state was attempted by a principal		An operation that manipulates state was attempted by a principal
	that was not allowed to modify that piece of state.		that was not allowed to modify that piece of state.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_name" numbered="true" toc="default">
	<section title="Name Errors" anchor="errors_name">		<name>Name Errors</name>
	<t>		<t>
	Names in NFSv4 are UTF-8 strings. When the strings are not		Names in NFSv4 are UTF-8 strings. When the strings are not
	valid UTF-8 or are of length zero, the error NFS4ERR_INVAL		valid UTF-8 or are of length zero, the error NFS4ERR_INVAL
	results. Besides this, there are a number of other errors		results. Besides this, there are a number of other errors
	to indicate specific problems with names.		to indicate specific problems with names.
	</t>		</t>
	<section title="NFS4ERR_BADCHAR (Error Code 10040)"		<section anchor="err_BADCHAR" numbered="true" toc="default">
	anchor="err_BADCHAR">		<name>NFS4ERR_BADCHAR (Error Code 10040)</name>
	<t>		<t>
	A UTF-8 string contains a character that is not supported		A UTF-8 string contains a character that is not supported
	by the server in the context in which it being used.		by the server in the context in which it being used.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_BADNAME (Error Code 10041)"		<section anchor="err_BADNAME" numbered="true" toc="default">
	anchor="err_BADNAME">		<name>NFS4ERR_BADNAME (Error Code 10041)</name>
	<t>		<t>
	A name string in a request consisted of valid UTF-8		A name string in a request consisted of valid UTF-8
	characters supported by the server, but the name is not		characters supported by the server, but the name is not
	supported by the server as a valid name for the current operation.		supported by the server as a valid name for the current operation.
	An example might be creating a file or directory named ".."		An example might be creating a file or directory named ".."
	on a server whose file system uses that name for links to		on a server whose file system uses that name for links to
	parent directories.		parent directories.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_NAMETOOLONG (Error Code 63)"		<section anchor="err_NAMETOOLONG" numbered="true" toc="default">
	anchor="err_NAMETOOLONG">		<name>NFS4ERR_NAMETOOLONG (Error Code 63)</name>
	<t>		<t>
	Returned when the filename in an operation exceeds the		Returned when the filename in an operation exceeds the
	server's implementation limit.		server's implementation limit.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_locking" numbered="true" toc="default">
	<section title="Locking Errors" anchor="errors_locking">		<name>Locking Errors</name>
	<t>		<t>
	This section deals with errors related to locking, both as to		This section deals with errors related to locking, both as to
	share reservations and byte-range locking. It does not deal		share reservations and byte-range locking. It does not deal
	with errors specific to the process of reclaiming locks. Those		with errors specific to the process of reclaiming locks. Those
	are dealt with in <xref target="errors_reclaim"></xref>.		are dealt with in <xref target="errors_reclaim" format="default"/>.
	</t>		</t>
	<section title="NFS4ERR_BAD_RANGE (Error Code 10042)"		<section anchor="err_BAD_RANGE" numbered="true" toc="default">
	anchor="err_BAD_RANGE">		<name>NFS4ERR_BAD_RANGE (Error Code 10042)</name>
	<t>		<t>
	The byte-range of a LOCK, LOCKT, or LOCKU operation is		The byte-range of a LOCK, LOCKT, or LOCKU operation is
	not allowed by the		not allowed by the
	server. For example, this error results when a server		server. For example, this error results when a server
	that only supports 32-bit ranges receives a range that		that only supports 32-bit ranges receives a range that
	cannot be handled by that server. (See		cannot be handled by that server. (See
	<xref target="OP_LOCK_DESCRIPTION" />.)		<xref target="OP_LOCK_DESCRIPTION" format="default"/>.)
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_DEADLOCK (Error Code 10045)"		<section anchor="err_DEADLOCK" numbered="true" toc="default">
	anchor="err_DEADLOCK">		<name>NFS4ERR_DEADLOCK (Error Code 10045)</name>
	<t>		<t>
	The server has been able to determine a byte-range locking		The server has been able to determine a byte-range locking
	deadlock condition for a READW_LT or WRITEW_LT LOCK operation.		deadlock condition for a READW_LT or WRITEW_LT LOCK operation.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_DENIED (Error Code 10010)"		<section anchor="err_DENIED" numbered="true" toc="default">
	anchor="err_DENIED">		<name>NFS4ERR_DENIED (Error Code 10010)</name>
	<t>		<t>
	An attempt to lock a file is denied. Since this may be a		An attempt to lock a file is denied. Since this may be a
	temporary condition, the client is encouraged to re-send the lock		temporary condition, the client is encouraged to re-send the lock
	request (but not with the same slot ID and		request (but not with the same slot ID and
	sequence ID; one or both MUST be different on the re-send) until the loc		sequence ID; one or both <bcp14>MUST</bcp14> be different on the re-send
	k is accepted. See		) until the lock is accepted. See
	<xref target="blocking_locks" /> for a discussion of the re-send.		<xref target="blocking_locks" format="default"/> for a discussion of the
	</t>		re-send.
	</section>		</t>
	<section title="NFS4ERR_LOCKED (Error Code 10012)"		</section>
	anchor="err_LOCKED">		<section anchor="err_LOCKED" numbered="true" toc="default">
	<t>		<name>NFS4ERR_LOCKED (Error Code 10012)</name>
			<t>
	A READ or WRITE operation was attempted on a file where there		A READ or WRITE operation was attempted on a file where there
	was a conflict between the I/O and an existing lock:		was a conflict between the I/O and an existing lock:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	There is a share reservation inconsistent with the I/O		There is a share reservation inconsistent with the I/O
	being done.		being done.
	</t>		</li>
	<t>		<li>
	The range to be read or written intersects an existing		The range to be read or written intersects an existing
	mandatory byte-range lock.		mandatory byte-range lock.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section anchor="err_LOCKS_HELD" numbered="true" toc="default">
	<section title="NFS4ERR_LOCKS_HELD (Error Code 10037)"		<name>NFS4ERR_LOCKS_HELD (Error Code 10037)</name>
	anchor="err_LOCKS_HELD">		<t>
	<t>
	An operation was prevented by the unexpected presence of locks.		An operation was prevented by the unexpected presence of locks.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_LOCK_NOTSUPP (Error Code 10043)"		<section anchor="err_LOCK_NOTSUPP" numbered="true" toc="default">
	anchor="err_LOCK_NOTSUPP">		<name>NFS4ERR_LOCK_NOTSUPP (Error Code 10043)</name>
	<t>		<t>
	A LOCK operation was attempted that would require the upgrade		A LOCK operation was attempted that would require the upgrade
	or downgrade of a byte-range lock range already held by the owner, and t he		or downgrade of a byte-range lock range already held by the owner, and t he
	server does not support atomic upgrade or downgrade of locks.		server does not support atomic upgrade or downgrade of locks.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_LOCK_RANGE (Error Code 10028)"		<section anchor="err_LOCK_RANGE" numbered="true" toc="default">
	anchor="err_LOCK_RANGE">		<name>NFS4ERR_LOCK_RANGE (Error Code 10028)</name>
	<t>		<t>
	A LOCK operation is operating on a range that overlaps in part a		A LOCK operation is operating on a range that overlaps in part a
	currently held byte-range lock for the current lock-owner and does not		currently held byte-range lock for the current lock-owner and does not
	precisely match a single such byte-range lock where the server		precisely match a single such byte-range lock where the server
	does not support this type of request, and thus does not		does not support this type of request, and thus does not
	implement POSIX locking semantics <xref target="fcntl"/>. See Sections		implement POSIX locking semantics <xref target="fcntl" format="default"/
	<xref target="OP_LOCK_IMPLEMENTATION" format="counter" />,		>. See Sections
	<xref target="OP_LOCKT_IMPLEMENTATION" format="counter" />, and		<xref target="OP_LOCK_IMPLEMENTATION" format="counter"/>,
	<xref target="OP_LOCKU_IMPLEMENTATION" format="counter" /> for a discuss		<xref target="OP_LOCKT_IMPLEMENTATION" format="counter"/>, and
	ion of		<xref target="OP_LOCKU_IMPLEMENTATION" format="counter"/> for a discussi
			on of
	how this applies to LOCK, LOCKT, and LOCKU respectively.		how this applies to LOCK, LOCKT, and LOCKU respectively.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_OPENMODE (Error Code 10038)"		<section anchor="err_OPENMODE" numbered="true" toc="default">
	anchor="err_OPENMODE">		<name>NFS4ERR_OPENMODE (Error Code 10038)</name>
	<t>		<t>
	The client attempted a READ, WRITE, LOCK, or other operation		The client attempted a READ, WRITE, LOCK, or other operation
	not sanctioned by the stateid passed (e.g., writing to a file		not sanctioned by the stateid passed (e.g., writing to a file
	opened for read-only access).		opened for read-only access).
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_SHARE_DENIED (Error Code 10015)"		<section anchor="err_SHARE_DENIED" numbered="true" toc="default">
	anchor="err_SHARE_DENIED">		<name>NFS4ERR_SHARE_DENIED (Error Code 10015)</name>
	<t>		<t>
	An attempt to OPEN a file with a share reservation has failed		An attempt to OPEN a file with a share reservation has failed
	because of a share conflict.		because of a share conflict.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_reclaim" numbered="true" toc="default">
	<section title="Reclaim Errors" anchor="errors_reclaim">		<name>Reclaim Errors</name>
	<t>		<t>
	These errors relate to the process of reclaiming locks after a		These errors relate to the process of reclaiming locks after a
	server restart.		server restart.
	</t>		</t>
	<section title="NFS4ERR_COMPLETE_ALREADY (Error Code 10054)"		<section anchor="err_COMPLETE_ALREADY" numbered="true" toc="default">
	anchor="err_COMPLETE_ALREADY">		<name>NFS4ERR_COMPLETE_ALREADY (Error Code 10054)</name>
	<t>		<t>
	The client previously sent a successful RECLAIM_COMPLETE		The client previously sent a successful RECLAIM_COMPLETE
	operation specifying the same scope, whether that scope is global		operation specifying the same scope, whether that scope is global
	or for the same file system in the case of a per-fs RECLAIM_COMPLETE.		or for the same file system in the case of a per-fs RECLAIM_COMPLETE.
	An additional RECLAIM_COMPLETE operation is not		An additional RECLAIM_COMPLETE operation is not necessary and results in
	necessary and results in this error.		this error.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_GRACE (Error Code 10013)"		<section anchor="err_GRACE" numbered="true" toc="default">
	anchor="err_GRACE">		<name>NFS4ERR_GRACE (Error Code 10013)</name>
	<t>		<t>
	This error is returned when the server is in its		This error is returned when the server is in its
	grace period with regard to the file system object for which		grace period with regard to the file system object for which
	the lock was requested. In this situation, a non-reclaim		the lock was requested. In this situation, a non-reclaim
	locking request cannot be granted. This can occur because either		locking request cannot be granted. This can occur because either:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The server does not have sufficient information about locks that		The server does not have sufficient information about locks that
	might be potentially reclaimed to determine whether the lock could		might be potentially reclaimed to determine whether the lock could
	be granted.		be granted.
	</t>		</li>
	<t>		<li>
	The request is made by a client responsible for reclaiming its		The request is made by a client responsible for reclaiming its
	locks that has not yet done the appropriate RECLAIM_COMPLETE		locks that has not yet done the appropriate RECLAIM_COMPLETE
	operation, allowing it to proceed to obtain new locks.		operation, allowing it to proceed to obtain new locks.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	In the case of a per-fs grace period,		In the case of a per-fs grace period,
	there may be clients, (i.e., those currently using the destination		there may be clients (i.e., those currently using the destination
	file system) who might be unaware of the circumstances resulting		file system) who might be unaware of the circumstances resulting
	in the initiation of the grace period. Such clients need to		in the initiation of the grace period. Such clients need to
	periodically retry the request until the grace period is over, just as		periodically retry the request until the grace period is over, just as
	other clients do.		other clients do.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_NO_GRACE (Error Code 10033)"		<section anchor="err_NO_GRACE" numbered="true" toc="default">
	anchor="err_NO_GRACE">		<name>NFS4ERR_NO_GRACE (Error Code 10033)</name>
	<t>		<t>
	A reclaim of client state was attempted in circumstances in		A reclaim of client state was attempted in circumstances in
	which the server cannot guarantee that conflicting state has		which the server cannot guarantee that conflicting state has
	not been provided to another client. This occurs in any of the		not been provided to another client. This occurs in any of the
	following situations.		following situations:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	There		There
	is no active grace period applying to the file system object		is no active grace period applying to the file system object
	for which the request was made.		for which the request was made.
	</t>		</li>
	<t>		<li>
	The client making the		The client making the
	request has no current role in reclaiming locks.		request has no current role in reclaiming locks.
	</t>		</li>
	<t>		<li>
	Previous operations have created a situation in which		Previous operations have created a situation in which
	the server is not able to determine that a reclaim-interfering		the server is not able to determine that a reclaim-interfering
	edge condition does not exist.		edge condition does not exist.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section anchor="err_RECLAIM_BAD" numbered="true" toc="default">
	<section title="NFS4ERR_RECLAIM_BAD (Error Code 10034)"		<name>NFS4ERR_RECLAIM_BAD (Error Code 10034)</name>
	anchor="err_RECLAIM_BAD">		<t>
	<t>
	The server has determined that a reclaim attempted by the client		The server has determined that a reclaim attempted by the client
	is not valid, i.e. the lock specified as being reclaimed could		is not valid, i.e., the lock specified as being reclaimed could
	not possibly have existed before the server restart or file		not possibly have existed before the server restart or file
	system migration event. A server		system migration event. A server
	is not obliged to make this determination and will typically rely		is not obliged to make this determination and will typically rely
	on the client to only reclaim locks that the client was granted prior		on the client to only reclaim locks that the client was granted prior
	to restart. However,		to restart. However,
	when a server does have reliable information to enable it to make		when a server does have reliable information to enable it to make
	this determination, this error indicates that the reclaim has		this determination, this error indicates that the reclaim has
	been rejected as invalid. This is as opposed to the error		been rejected as invalid. This is as opposed to the error
	NFS4ERR_RECLAIM_CONFLICT (see <xref target="err_RECLAIM_CONFLICT"/>)		NFS4ERR_RECLAIM_CONFLICT (see <xref target="err_RECLAIM_CONFLICT" format= "default"/>)
	where the server can only determine that		where the server can only determine that
	there has been an invalid reclaim, but cannot determine		there has been an invalid reclaim, but cannot determine
	which request is invalid.		which request is invalid.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_RECLAIM_CONFLICT (Error Code 10035)"		<section anchor="err_RECLAIM_CONFLICT" numbered="true" toc="default">
	anchor="err_RECLAIM_CONFLICT">		<name>NFS4ERR_RECLAIM_CONFLICT (Error Code 10035)</name>
	<t>		<t>
	The reclaim attempted by the client has encountered a conflict		The reclaim attempted by the client has encountered a conflict
	and cannot be satisfied. This potentially indicates a misbehaving		and cannot be satisfied. This potentially indicates a misbehaving
	client, although not necessarily the one receiving the error.		client, although not necessarily the one receiving the error.
	The misbehavior might be on the part of the client that		The misbehavior might be on the part of the client that
	established the lock with which this client conflicted. See also		established the lock with which this client conflicted. See also
	<xref target="err_RECLAIM_BAD"/> for the related error,		<xref target="err_RECLAIM_BAD" format="default"/> for the related error,
	NFS4ERR_RECLAIM_BAD.		NFS4ERR_RECLAIM_BAD.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_pnfs" numbered="true" toc="default">
	<section title="pNFS Errors" anchor="errors_pnfs">		<name>pNFS Errors</name>
	<t>		<t>
	This section deals with pNFS-related errors including those		This section deals with pNFS-related errors including those
	that are associated with using NFSv4.1 to communicate with a		that are associated with using NFSv4.1 to communicate with a
	data server.		data server.
	</t>		</t>
	<section title="NFS4ERR_BADIOMODE (Error Code 10049)"		<section anchor="err_BADIOMODE" numbered="true" toc="default">
	anchor="err_BADIOMODE">		<name>NFS4ERR_BADIOMODE (Error Code 10049)</name>
	<t>		<t>
	An invalid or inappropriate layout iomode was specified.		An invalid or inappropriate layout iomode was specified.
	For example an inappropriate layout iomode, suppose		For example an inappropriate layout iomode, suppose
	a client's LAYOUTGET operation specified an iomode of		a client's LAYOUTGET operation specified an iomode of
	LAYOUTIOMODE4_RW, and the server is neither able nor willing		LAYOUTIOMODE4_RW, and the server is neither able nor willing
	to let the client send write requests to data servers; the server		to let the client send write requests to data servers; the server
	can reply with NFS4ERR_BADIOMODE. The client would then		can reply with NFS4ERR_BADIOMODE. The client would then
	send another LAYOUTGET with an iomode of LAYOUTIOMODE4_READ.		send another LAYOUTGET with an iomode of LAYOUTIOMODE4_READ.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_BADLAYOUT (Error Code 10050)"		<section anchor="err_BADLAYOUT" numbered="true" toc="default">
	anchor="err_BADLAYOUT">		<name>NFS4ERR_BADLAYOUT (Error Code 10050)</name>
	<t>		<t>
	The layout specified is invalid in some way. For LAYOUTCOMMIT,		The layout specified is invalid in some way. For LAYOUTCOMMIT,
	this indicates that the specified layout is not held by the		this indicates that the specified layout is not held by the
	client or is not of mode LAYOUTIOMODE4_RW. For LAYOUTGET,		client or is not of mode LAYOUTIOMODE4_RW. For LAYOUTGET,
	it indicates that a layout matching the client's specification		it indicates that a layout matching the client's specification
	as to minimum length cannot be granted.		as to minimum length cannot be granted.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_LAYOUTTRYLATER (Error Code 10058)"		<section anchor="err_LAYOUTTRYLATER" numbered="true" toc="default">
	anchor="err_LAYOUTTRYLATER">		<name>NFS4ERR_LAYOUTTRYLATER (Error Code 10058)</name>
	<t>		<t>
	Layouts are temporarily unavailable for the file. The client		Layouts are temporarily unavailable for the file. The client
	should re-send later (but not with the same slot ID and		should re-send later (but not with the same slot ID and
	sequence ID; one or both MUST be different on the re-send).		sequence ID; one or both <bcp14>MUST</bcp14> be different on the re-send
	</t>		).
	</section>		</t>
	<section title="NFS4ERR_LAYOUTUNAVAILABLE (Error Code 10059)"		</section>
	anchor="err_LAYOUTUNAVAILABLE">		<section anchor="err_LAYOUTUNAVAILABLE" numbered="true" toc="default">
	<t>		<name>NFS4ERR_LAYOUTUNAVAILABLE (Error Code 10059)</name>
			<t>
	Returned when layouts are not available for the current file		Returned when layouts are not available for the current file
	system or the particular specified file.		system or the particular specified file.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_NOMATCHING_LAYOUT (Error Code 10060)"		<section anchor="err_NOMATCHING_LAYOUT" numbered="true" toc="default">
	anchor="err_NOMATCHING_LAYOUT">		<name>NFS4ERR_NOMATCHING_LAYOUT (Error Code 10060)</name>
	<t>		<t>
	Returned when layouts are recalled and the client has no layouts		Returned when layouts are recalled and the client has no layouts
	matching the specification of the layouts being recalled.		matching the specification of the layouts being recalled.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_PNFS_IO_HOLE (Error Code 10075)"		<section anchor="err_PNFS_IO_HOLE" numbered="true" toc="default">
	anchor="err_PNFS_IO_HOLE">		<name>NFS4ERR_PNFS_IO_HOLE (Error Code 10075)</name>
	<t>		<t>
	The pNFS client has attempted to read from or write to an		The pNFS client has attempted to read from or write to an
	illegal hole of a file of a data server that is using		illegal hole of a file of a data server that is using
	sparse packing. See <xref target="sparse_dense" />.		sparse packing. See <xref target="sparse_dense" format="default"/>.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_PNFS_NO_LAYOUT (Error Code 10080)"		<section anchor="err_PNFS_NO_LAYOUT" numbered="true" toc="default">
	anchor="err_PNFS_NO_LAYOUT">		<name>NFS4ERR_PNFS_NO_LAYOUT (Error Code 10080)</name>
	<t>		<t>
	The pNFS client has attempted to read from or write to a file		The pNFS client has attempted to read from or write to a file
	(using a request to a data server) without holding a valid		(using a request to a data server) without holding a valid
	layout. This includes the case where the client had a layout,		layout. This includes the case where the client had a layout,
	but the iomode does not allow a WRITE.		but the iomode does not allow a WRITE.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_RETURNCONFLICT (Error Code 10086)"		<section anchor="err_RETURNCONFLICT" numbered="true" toc="default">
	anchor="err_RETURNCONFLICT">		<name>NFS4ERR_RETURNCONFLICT (Error Code 10086)</name>
	<t>		<t>
	A layout		A layout
	is unavailable due to an attempt to perform the LAYOUTGET		is unavailable due to an attempt to perform the LAYOUTGET
	before a pending LAYOUTRETURN on the file has been received.		before a pending LAYOUTRETURN on the file has been received.
	See <xref target="layout_server_consider" />.		See <xref target="layout_server_consider" format="default"/>.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_UNKNOWN_LAYOUTTYPE (Error Code 10062)"		<section anchor="err_UNKNOWN_LAYOUTTYPE" numbered="true" toc="default"
	anchor="err_UNKNOWN_LAYOUTTYPE">		>
	<t>		<name>NFS4ERR_UNKNOWN_LAYOUTTYPE (Error Code 10062)</name>
			<t>
	The client has specified a layout type that is not supported by		The client has specified a layout type that is not supported by
	the server.		the server.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_sess_use" numbered="true" toc="default">
	<section title="Session Use Errors" anchor="errors_sess_use">		<name>Session Use Errors</name>
	<t>		<t>
	This section deals with errors encountered when using sessions,		This section deals with errors encountered when using sessions,
	that is, errors encountered when a request uses a Sequence		that is, errors encountered when a request uses a Sequence
	(i.e., either SEQUENCE or CB_SEQUENCE) operation.		(i.e., either SEQUENCE or CB_SEQUENCE) operation.
	</t>		</t>
	<section title="NFS4ERR_BADSESSION (Error Code 10052)"		<section anchor="err_BADSESSION" numbered="true" toc="default">
	anchor="err_BADSESSION">		<name>NFS4ERR_BADSESSION (Error Code 10052)</name>
	<t>		<t>
	The specified session ID is unknown to the server		The specified session ID is unknown to the server
	to which the operation is addressed.		to which the operation is addressed.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_BADSLOT (Error Code 10053)"		<section anchor="err_BADSLOT" numbered="true" toc="default">
	anchor="err_BADSLOT">		<name>NFS4ERR_BADSLOT (Error Code 10053)</name>
	<t>		<t>
	The requester sent a Sequence operation		The requester sent a Sequence operation
	that attempted to use a slot the replier		that attempted to use a slot the replier
	does not have in its slot table. It is possible the		does not have in its slot table. It is possible the
	slot may have been retired.		slot may have been retired.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_BAD_HIGH_SLOT (Error Code 10077)"		<section anchor="err_BAD_HIGH_SLOT" numbered="true" toc="default">
	anchor="err_BAD_HIGH_SLOT">		<name>NFS4ERR_BAD_HIGH_SLOT (Error Code 10077)</name>
	<t>		<t>
	The highest_slot argument in a Sequence operation		The highest_slot argument in a Sequence operation
	exceeds the replier's enforced highest_slotid.		exceeds the replier's enforced highest_slotid.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_CB_PATH_DOWN (Error Code 10048)"		<section anchor="err_CB_PATH_DOWN" numbered="true" toc="default">
	anchor="err_CB_PATH_DOWN">		<name>NFS4ERR_CB_PATH_DOWN (Error Code 10048)</name>
	<t>		<t>
	There is a problem contacting the client via		There is a problem contacting the client via
	the callback path. The function of this error has		the callback path. The function of this error has
	been mostly superseded by the use of		been mostly superseded by the use of
	status flags in the reply to the SEQUENCE		status flags in the reply to the SEQUENCE
	operation (see <xref target="OP_SEQUENCE" />).		operation (see <xref target="OP_SEQUENCE" format="default"/>).
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_DEADSESSION (Error Code 10078)"		<section anchor="err_DEADSESSION" numbered="true" toc="default">
	anchor="err_DEADSESSION">		<name>NFS4ERR_DEADSESSION (Error Code 10078)</name>
	<t>		<t>
	The specified session is a persistent session that is		The specified session is a persistent session that is
	dead and does not accept new		dead and does not accept new
	requests or perform new operations on existing requests		requests or perform new operations on existing requests
	(in the case in which a request was partially executed		(in the case in which a request was partially executed
	before server restart).		before server restart).
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_CONN_NOT_BOUND_TO_SESSION (Error Code 10055)"		<section anchor="err_CONN_NOT_BOUND_TO_SESSION" numbered="true" toc="d
	anchor="err_CONN_NOT_BOUND_TO_SESSION">		efault">
	<t>		<name>NFS4ERR_CONN_NOT_BOUND_TO_SESSION (Error Code 10055)</name>
			<t>
	A Sequence operation was sent on a connection that has not		A Sequence operation was sent on a connection that has not
	been associated with the specified session,		been associated with the specified session,
	where the client specified that connection association		where the client specified that connection association
	was to be enforced with SP4_MACH_CRED or SP4_SSV state protection.		was to be enforced with SP4_MACH_CRED or SP4_SSV state protection.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_SEQ_FALSE_RETRY (Error Code 10076)"		<section anchor="err_SEQ_FALSE_RETRY" numbered="true" toc="default">
	anchor="err_SEQ_FALSE_RETRY">		<name>NFS4ERR_SEQ_FALSE_RETRY (Error Code 10076)</name>
	<t>		<t>
	The requester sent a Sequence operation with a		The requester sent a Sequence operation with a
	slot ID and sequence ID that are in the reply cache, but		slot ID and sequence ID that are in the reply cache, but
	the replier has detected that the retried request		the replier has detected that the retried request
	is not the same as the original request.		is not the same as the original request.
	See <xref target="false_retry"/>.		See <xref target="false_retry" format="default"/>.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_SEQ_MISORDERED (Error Code 10063)"		<section anchor="err_SEQ_MISORDERED" numbered="true" toc="default">
	anchor="err_SEQ_MISORDERED">		<name>NFS4ERR_SEQ_MISORDERED (Error Code 10063)</name>
	<t>		<t>
	The requester sent a Sequence operation		The requester sent a Sequence operation
	with an invalid sequence ID.		with an invalid sequence ID.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_sess_mgt" numbered="true" toc="default">
	<section title="Session Management Errors" anchor="errors_sess_mgt">		<name>Session Management Errors</name>
	<t>		<t>
	This section deals with errors associated with requests used		This section deals with errors associated with requests used
	in session management.		in session management.
	</t>		</t>
	<section title="NFS4ERR_BACK_CHAN_BUSY (Error Code 10057)"		<section anchor="err_BACK_CHAN_BUSY" numbered="true" toc="default">
	anchor="err_BACK_CHAN_BUSY">		<name>NFS4ERR_BACK_CHAN_BUSY (Error Code 10057)</name>
	<t>		<t>
	An attempt was made to destroy a session when the session		An attempt was made to destroy a session when the session
	cannot be destroyed because the server has		cannot be destroyed because the server has
	callback requests outstanding.		callback requests outstanding.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_BAD_SESSION_DIGEST (Error Code 10051)"		<section anchor="err_BAD_SESSION_DIGEST" numbered="true" toc="default"
	anchor="err_BAD_SESSION_DIGEST">		>
	<t>		<name>NFS4ERR_BAD_SESSION_DIGEST (Error Code 10051)</name>
			<t>
	The digest used in a SET_SSV request is not valid.		The digest used in a SET_SSV request is not valid.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_client_mgt" numbered="true" toc="default">
	<section title="Client Management Errors" anchor="errors_client_mgt">		<name>Client Management Errors</name>
	<t>		<t>
	This section deals with errors associated with requests used		This section deals with errors associated with requests used
	to create and manage client IDs.		to create and manage client IDs.
	</t>		</t>
	<section title="NFS4ERR_CLIENTID_BUSY (Error Code 10074)"		<section anchor="err_CLIENTID_BUSY" numbered="true" toc="default">
	anchor="err_CLIENTID_BUSY">		<name>NFS4ERR_CLIENTID_BUSY (Error Code 10074)</name>
	<t>		<t>
	The DESTROY_CLIENTID operation has found there are		The DESTROY_CLIENTID operation has found there are
	sessions and/or unexpired state associated with the		sessions and/or unexpired state associated with the
	client ID to be destroyed.		client ID to be destroyed.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_CLID_INUSE (Error Code 10017)"		<section anchor="err_CLID_INUSE" numbered="true" toc="default">
	anchor="err_CLID_INUSE">		<name>NFS4ERR_CLID_INUSE (Error Code 10017)</name>
	<t>		<t>
	While processing an EXCHANGE_ID operation, the server was presented		While processing an EXCHANGE_ID operation, the server was presented
	with a co_ownerid field that matches an existing client with		with a co_ownerid field that matches an existing client with
	valid leased state, but the principal sending the EXCHANGE_ID		valid leased state, but the principal sending the EXCHANGE_ID
	operation differs from the principal that established the existing		operation differs from the principal that established the existing
	client.		client.
	This indicates a collision (most likely due to chance) between		This indicates a collision (most likely due to chance) between
	clients. The client should recover by changing the		clients. The client should recover by changing the
	co_ownerid and re-sending EXCHANGE_ID (but not with the same slot ID and		co_ownerid and re-sending EXCHANGE_ID (but not with the same slot ID and
	sequence ID; one or both MUST be different on the re-send).		sequence ID; one or both <bcp14>MUST</bcp14> be different on the re-send
	</t>		).
	</section>		</t>
	<section title="NFS4ERR_ENCR_ALG_UNSUPP (Error Code 10079)"		</section>
	anchor="err_ENCR_ALG_UNSUPP">		<section anchor="err_ENCR_ALG_UNSUPP" numbered="true" toc="default">
	<t>		<name>NFS4ERR_ENCR_ALG_UNSUPP (Error Code 10079)</name>
			<t>
	An EXCHANGE_ID was sent that specified state protection		An EXCHANGE_ID was sent that specified state protection
	via SSV, and where the set of encryption algorithms presented		via SSV, and where the set of encryption algorithms presented
	by the client did not include any supported by the server.		by the client did not include any supported by the server.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_HASH_ALG_UNSUPP (Error Code 10072)"		<section anchor="err_HASH_ALG_UNSUPP" numbered="true" toc="default">
	anchor="err_HASH_ALG_UNSUPP">		<name>NFS4ERR_HASH_ALG_UNSUPP (Error Code 10072)</name>
	<t>		<t>
	An EXCHANGE_ID was sent that specified state protection		An EXCHANGE_ID was sent that specified state protection
	via SSV, and where the set of hashing algorithms presented		via SSV, and where the set of hashing algorithms presented
	by the client did not include any supported by the server.		by the client did not include any supported by the server.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_STALE_CLIENTID (Error Code 10022)"		<section anchor="err_STALE_CLIENTID" numbered="true" toc="default">
	anchor="err_STALE_CLIENTID">		<name>NFS4ERR_STALE_CLIENTID (Error Code 10022)</name>
	<t>		<t>
	A client ID not recognized by the server was passed to an		A client ID not recognized by the server was passed to an
	operation. Note that unlike the case of NFSv4.0, client IDs		operation. Note that unlike the case of NFSv4.0, client IDs
	are not passed explicitly to the server in ordinary locking		are not passed explicitly to the server in ordinary locking
	operations and cannot result in this error. Instead, when		operations and cannot result in this error. Instead, when
	there is a server restart, it is first manifested through		there is a server restart, it is first manifested through
	an error on the associated session, and the staleness of the		an error on the associated session, and the staleness of the
	client ID is detected when trying to associate a client ID		client ID is detected when trying to associate a client ID
	with a new session.		with a new session.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_deleg" numbered="true" toc="default">
	<section title="Delegation Errors" anchor="errors_deleg">		<name>Delegation Errors</name>
	<t>		<t>
	This section deals with errors associated with requesting and		This section deals with errors associated with requesting and
	returning delegations.		returning delegations.
	</t>		</t>
	<section title="NFS4ERR_DELEG_ALREADY_WANTED (Error Code 10056)"		<section anchor="err_DELEG_ALREADY_WANTED" numbered="true" toc="defaul
	anchor="err_DELEG_ALREADY_WANTED">		t">
	<t>		<name>NFS4ERR_DELEG_ALREADY_WANTED (Error Code 10056)</name>
			<t>
	The client has requested a delegation when it had already		The client has requested a delegation when it had already
	registered that it wants that same delegation.		registered that it wants that same delegation.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_DIRDELEG_UNAVAIL (Error Code 10084)"		<section anchor="err_DIRDELEG_UNAVAIL" numbered="true" toc="default">
	anchor="err_DIRDELEG_UNAVAIL">		<name>NFS4ERR_DIRDELEG_UNAVAIL (Error Code 10084)</name>
	<t>		<t>
	This error is returned when the server is unable or unwilling		This error is returned when the server is unable or unwilling
	to provide a requested directory delegation.		to provide a requested directory delegation.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_RECALLCONFLICT (Error Code 10061)"		<section anchor="err_RECALLCONFLICT" numbered="true" toc="default">
	anchor="err_RECALLCONFLICT">		<name>NFS4ERR_RECALLCONFLICT (Error Code 10061)</name>
	<t>		<t>
	A recallable object (i.e., a layout or delegation)		A recallable object (i.e., a layout or delegation)
	is unavailable due to a conflicting recall operation that is		is unavailable due to a conflicting recall operation that is
	currently in progress for that object.		currently in progress for that object.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_REJECT_DELEG (Error Code 10085)"		<section anchor="err_REJECT_DELEG" numbered="true" toc="default">
	anchor="err_REJECT_DELEG">		<name>NFS4ERR_REJECT_DELEG (Error Code 10085)</name>
	<t>		<t>
	The callback operation invoked to deal with a new delegation has		The callback operation invoked to deal with a new delegation has
	rejected it.		rejected it.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_attr" numbered="true" toc="default">
	<section title="Attribute Handling Errors" anchor="errors_attr">		<name>Attribute Handling Errors</name>
	<t>		<t>
	This section deals with errors specific to attribute handling		This section deals with errors specific to attribute handling
	within NFSv4.		within NFSv4.
	</t>		</t>
	<section title="NFS4ERR_ATTRNOTSUPP (Error Code 10032)"		<section anchor="err_ATTRNOTSUPP" numbered="true" toc="default">
	anchor="err_ATTRNOTSUPP">		<name>NFS4ERR_ATTRNOTSUPP (Error Code 10032)</name>
	<t>		<t>
	An attribute specified is not supported by the server. This		An attribute specified is not supported by the server. This
	error MUST NOT be returned by the GETATTR operation.		error <bcp14>MUST NOT</bcp14> be returned by the GETATTR operation.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_BADOWNER (Error Code 10039)"		<section anchor="err_BADOWNER" numbered="true" toc="default">
	anchor="err_BADOWNER">		<name>NFS4ERR_BADOWNER (Error Code 10039)</name>
	<t>		<t>
	This error is returned when an owner or owner_group attribute value or t he who		This error is returned when an owner or owner_group attribute value or t he who
	field of an ACE within an ACL attribute value cannot be		field of an ACE within an ACL attribute value cannot be
	translated to a local representation.		translated to a local representation.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_NOT_SAME (Error Code 10027)"		<section anchor="err_NOT_SAME" numbered="true" toc="default">
	anchor="err_NOT_SAME">		<name>NFS4ERR_NOT_SAME (Error Code 10027)</name>
	<t>		<t>
	This error is returned by the VERIFY operation to signify		This error is returned by the VERIFY operation to signify
	that the attributes compared were not the same as those provided		that the attributes compared were not the same as those provided
	in the client's request.		in the client's request.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_SAME (Error Code 10009)"		<section anchor="err_SAME" numbered="true" toc="default">
	anchor="err_SAME">		<name>NFS4ERR_SAME (Error Code 10009)</name>
	<t>		<t>
	This error is returned by the NVERIFY operation to signify		This error is returned by the NVERIFY operation to signify
	that the attributes compared were the same as those provided		that the attributes compared were the same as those provided
	in the client's request.		in the client's request.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="errors_obs" numbered="true" toc="default">
	<section title="Obsoleted Errors" anchor="errors_obs">		<name>Obsoleted Errors</name>
	<t>		<t>
	These errors MUST NOT be generated by any NFSv4.1 operation.		These errors <bcp14>MUST NOT</bcp14> be generated by any NFSv4.1 operation
			.
	This can be for a number of reasons.		This can be for a number of reasons.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The function provided by the error has been superseded		The function provided by the error has been superseded
	by one of the status bits returned by the SEQUENCE		by one of the status bits returned by the SEQUENCE
	operation.		operation.
	</t>		</li>
	<t>		<li>
	The new session structure and associated change in		The new session structure and associated change in
	locking have made the error unnecessary.		locking have made the error unnecessary.
	</t>		</li>
	<t>		<li>
	There has been a restructuring of some errors for		There has been a restructuring of some errors for
	NFSv4.1 that resulted in the elimination of certain errors.		NFSv4.1 that resulted in the elimination of certain errors.
	</t>		</li>
	</list>		</ul>
	</t>		<section anchor="err_BAD_SEQID" numbered="true" toc="default">
	<section title="NFS4ERR_BAD_SEQID (Error Code 10026)"		<name>NFS4ERR_BAD_SEQID (Error Code 10026)</name>
	anchor="err_BAD_SEQID">		<t>
	<t>
	The sequence number (seqid) in a locking request is neither the		The sequence number (seqid) in a locking request is neither the
	next expected number or the last number processed. These		next expected number or the last number processed. These
	seqids are ignored in NFSv4.1.		seqids are ignored in NFSv4.1.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_LEASE_MOVED (Error Code 10031)"		<section anchor="err_LEASE_MOVED" numbered="true" toc="default">
	anchor="err_LEASE_MOVED">		<name>NFS4ERR_LEASE_MOVED (Error Code 10031)</name>
	<t>		<t>
	A lease being renewed is associated with a file system		A lease being renewed is associated with a file system
	that has been migrated to a new server. The error has		that has been migrated to a new server. The error has
	been superseded by the SEQ4_STATUS_LEASE_MOVED status bit		been superseded by the SEQ4_STATUS_LEASE_MOVED status bit
	(see <xref target="OP_SEQUENCE" />).		(see <xref target="OP_SEQUENCE" format="default"/>).
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_NXIO (Error Code 5)"		<section anchor="err_NXIO" numbered="true" toc="default">
	anchor="err_NXIO">		<name>NFS4ERR_NXIO (Error Code 5)</name>
	<t>		<t>
	I/O error. No such device or address. This error is		I/O error. No such device or address. This error is
	for errors involving block and character device access,		for errors involving block and character device access,
	but because NFSv4.1 is not a device-access protocol, this		but because NFSv4.1 is not a device-access protocol, this
	error is not applicable.		error is not applicable.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_RESTOREFH (Error Code 10030)"		<section anchor="err_RESTOREFH" numbered="true" toc="default">
	anchor="err_RESTOREFH">		<name>NFS4ERR_RESTOREFH (Error Code 10030)</name>
	<t>		<t>
	The RESTOREFH operation does not have a saved filehandle		The RESTOREFH operation does not have a saved filehandle
	(identified by SAVEFH) to operate upon. In NFSv4.1, this error has		(identified by SAVEFH) to operate upon. In NFSv4.1, this error has
	been superseded by NFS4ERR_NOFILEHANDLE.		been superseded by NFS4ERR_NOFILEHANDLE.
	</t>		</t>
	</section>		</section>
	<section title="NFS4ERR_STALE_STATEID (Error Code 10023)"		<section anchor="err_STALE_STATEID" numbered="true" toc="default">
	anchor="err_STALE_STATEID">		<name>NFS4ERR_STALE_STATEID (Error Code 10023)</name>
	<t>		<t>
	A stateid generated by an earlier server instance was		A stateid generated by an earlier server instance was
	used. This error is moot in NFSv4.1 because all operations that		used. This error is moot in NFSv4.1 because all operations that
	take a stateid MUST be preceded by the SEQUENCE operation,		take a stateid <bcp14>MUST</bcp14> be preceded by the SEQUENCE operation ,
	and the earlier server instance is detected by the session		and the earlier server instance is detected by the session
	infrastructure that supports SEQUENCE.		infrastructure that supports SEQUENCE.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			</section>
	</section>
	<!-- When adding new errors above, add them to the next section under -->
	<!-- the appropriate operation; the next table for errors to -->
	<!-- operations is automatically generated. -->
	<section title="Operations and Their Valid Errors">		<section numbered="true" toc="default">
	<t>		<name>Operations and Their Valid Errors</name>
			<t>
	This section contains a table that gives the valid error returns		This section contains a table that gives the valid error returns
	for each protocol operation. The error code NFS4_OK (indicating		for each protocol operation. The error code NFS4_OK (indicating
	no error) is not listed but should be understood to be returnable		no error) is not listed but should be understood to be returnable
	by all operations with two important exceptions:		by all operations with two important exceptions:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	The operations that MUST NOT be implemented:		<li>
			The operations that <bcp14>MUST NOT</bcp14> be implemented:
	OPEN_CONFIRM, RELEASE_LOCKOWNER, RENEW, SETCLIENTID, and		OPEN_CONFIRM, RELEASE_LOCKOWNER, RENEW, SETCLIENTID, and
	SETCLIENTID_CONFIRM.		SETCLIENTID_CONFIRM.
	</t>		</li>
	<t>		<li>
	The invalid operation: ILLEGAL.		The invalid operation: ILLEGAL.
	</t>		</li>
	</list>		</ul>
	</t>		<table anchor="op_error_returns" align="center">
	<texttable anchor='op_error_returns'>		<name>Valid Error Returns for Each Protocol Operation</name>
	<preamble> Valid Error Returns for Each Protocol		<thead>
	Operation </preamble>		<tr>
			<th align="left">Operation</th>
	<ttcol align='left'>Operation</ttcol>		<th align="left">Errors</th>
	<ttcol align='left'>Errors</ttcol>		</tr>
	<!-- DO NOT MOVE THIS OR THE NEXT LINE - IT MUST BE AT THE START OF TABLE -->		</thead>
	<!-- STARTOFTHEERRORTABLE -->		<tbody>
			<tr>
	<c>ACCESS</c>		<td align="left">ACCESS</td>
	<c>		<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_IO,		NFS4ERR_IO,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>BACKCHANNEL_CTL</c>		<tr>
	<c>		<td align="left">BACKCHANNEL_CTL</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_NOENT,		NFS4ERR_NOENT,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>BIND_CONN_TO_SESSION</c>		<tr>
	<c>		<td align="left">BIND_CONN_TO_SESSION</td>
			<td align="left">
	NFS4ERR_BADSESSION,		NFS4ERR_BADSESSION,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_SESSION_DIGEST,		NFS4ERR_BAD_SESSION_DIGEST,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_NOT_ONLY_OP,		NFS4ERR_NOT_ONLY_OP,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CLOSE</c>		<tr>
	<c>		<td align="left">CLOSE</td>
			<td align="left">
	NFS4ERR_ADMIN_REVOKED,		NFS4ERR_ADMIN_REVOKED,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_EXPIRED,		NFS4ERR_EXPIRED,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_LOCKS_HELD,		NFS4ERR_LOCKS_HELD,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	NFS4ERR_OLD_STATEID,		NFS4ERR_OLD_STATEID,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_CRED		NFS4ERR_WRONG_CRED
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>COMMIT</c>		<tr>
	<c>		<td align="left">COMMIT</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_IO,		NFS4ERR_IO,
	NFS4ERR_ISDIR,		NFS4ERR_ISDIR,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_SYMLINK,		NFS4ERR_SYMLINK,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CREATE</c>		<tr>
	<c>		<td align="left">CREATE</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_ATTRNOTSUPP,		NFS4ERR_ATTRNOTSUPP,
	NFS4ERR_BADCHAR,		NFS4ERR_BADCHAR,
	NFS4ERR_BADNAME,		NFS4ERR_BADNAME,
	NFS4ERR_BADOWNER,		NFS4ERR_BADOWNER,
	NFS4ERR_BADTYPE,		NFS4ERR_BADTYPE,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DQUOT,		NFS4ERR_DQUOT,
	skipping to change at line 25187 ¶		skipping to change at line 25569 ¶
	NFS4ERR_PERM,		NFS4ERR_PERM,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_ROFS,		NFS4ERR_ROFS,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_UNSAFE_COMPOUND		NFS4ERR_UNSAFE_COMPOUND
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CREATE_SESSION</c>		<tr>
	<c>		<td align="left">CREATE_SESSION</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_CLID_INUSE,		NFS4ERR_CLID_INUSE,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_NOENT,		NFS4ERR_NOENT,
	NFS4ERR_NOT_ONLY_OP,		NFS4ERR_NOT_ONLY_OP,
	NFS4ERR_NOSPC,		NFS4ERR_NOSPC,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SEQ_MISORDERED,		NFS4ERR_SEQ_MISORDERED,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE_CLIENTID,		NFS4ERR_STALE_CLIENTID,
	NFS4ERR_TOOSMALL,		NFS4ERR_TOOSMALL,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_CRED		NFS4ERR_WRONG_CRED
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>DELEGPURGE</c>		<tr>
	<c>		<td align="left">DELEGPURGE</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_NOTSUPP,		NFS4ERR_NOTSUPP,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_CRED		NFS4ERR_WRONG_CRED
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>DELEGRETURN</c>		<tr>
	<c>		<td align="left">DELEGRETURN</td>
			<td align="left">
	NFS4ERR_ADMIN_REVOKED,		NFS4ERR_ADMIN_REVOKED,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DELEG_REVOKED,		NFS4ERR_DELEG_REVOKED,
	NFS4ERR_EXPIRED,		NFS4ERR_EXPIRED,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	skipping to change at line 25260 ¶		skipping to change at line 25639 ¶
	NFS4ERR_OLD_STATEID,		NFS4ERR_OLD_STATEID,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_CRED		NFS4ERR_WRONG_CRED
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>DESTROY_CLIENTID</c>		<tr>
	<c>		<td align="left">DESTROY_CLIENTID</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_CLIENTID_BUSY,		NFS4ERR_CLIENTID_BUSY,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_NOT_ONLY_OP,		NFS4ERR_NOT_ONLY_OP,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE_CLIENTID,		NFS4ERR_STALE_CLIENTID,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_CRED		NFS4ERR_WRONG_CRED
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>DESTROY_SESSION</c>		<tr>
	<c>		<td align="left">DESTROY_SESSION</td>
			<td align="left">
	NFS4ERR_BACK_CHAN_BUSY,		NFS4ERR_BACK_CHAN_BUSY,
	NFS4ERR_BADSESSION,		NFS4ERR_BADSESSION,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_CB_PATH_DOWN,		NFS4ERR_CB_PATH_DOWN,
	NFS4ERR_CONN_NOT_BOUND_TO_SESSION,		NFS4ERR_CONN_NOT_BOUND_TO_SESSION,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_NOT_ONLY_OP,		NFS4ERR_NOT_ONLY_OP,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE_CLIENTID,		NFS4ERR_STALE_CLIENTID,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_CRED		NFS4ERR_WRONG_CRED
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>EXCHANGE_ID</c>		<tr>
	<c>		<td align="left">EXCHANGE_ID</td>
			<td align="left">
	NFS4ERR_BADCHAR,		NFS4ERR_BADCHAR,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_CLID_INUSE,		NFS4ERR_CLID_INUSE,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_ENCR_ALG_UNSUPP,		NFS4ERR_ENCR_ALG_UNSUPP,
	NFS4ERR_HASH_ALG_UNSUPP,		NFS4ERR_HASH_ALG_UNSUPP,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_NOENT,		NFS4ERR_NOENT,
	NFS4ERR_NOT_ONLY_OP,		NFS4ERR_NOT_ONLY_OP,
	NFS4ERR_NOT_SAME,		NFS4ERR_NOT_SAME,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>FREE_STATEID</c>		<tr>
	<c>		<td align="left">FREE_STATEID</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_LOCKS_HELD,		NFS4ERR_LOCKS_HELD,
	NFS4ERR_OLD_STATEID,		NFS4ERR_OLD_STATEID,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_CRED		NFS4ERR_WRONG_CRED
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>GET_DIR_DELEGATION</c>		<tr>
	<c>		<td align="left">GET_DIR_DELEGATION</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DIRDELEG_UNAVAIL,		NFS4ERR_DIRDELEG_UNAVAIL,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_GRACE,		NFS4ERR_GRACE,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_IO,		NFS4ERR_IO,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	skipping to change at line 25376 ¶		skipping to change at line 25750 ¶
	NFS4ERR_NOTDIR,		NFS4ERR_NOTDIR,
	NFS4ERR_NOTSUPP,		NFS4ERR_NOTSUPP,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>GETATTR</c>		<tr>
	<c>		<td align="left">GETATTR</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_GRACE,		NFS4ERR_GRACE,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_IO,		NFS4ERR_IO,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>GETDEVICEINFO</c>		<tr>
	<c>		<td align="left">GETDEVICEINFO</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_NOENT,		NFS4ERR_NOENT,
	NFS4ERR_NOTSUPP,		NFS4ERR_NOTSUPP,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOOSMALL,		NFS4ERR_TOOSMALL,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_UNKNOWN_LAYOUTTYPE		NFS4ERR_UNKNOWN_LAYOUTTYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>GETDEVICELIST</c>		<tr>
	<c>		<td align="left">GETDEVICELIST</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_COOKIE,		NFS4ERR_BAD_COOKIE,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_IO,		NFS4ERR_IO,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	NFS4ERR_NOTSUPP,		NFS4ERR_NOTSUPP,
	NFS4ERR_NOT_SAME,		NFS4ERR_NOT_SAME,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_UNKNOWN_LAYOUTTYPE		NFS4ERR_UNKNOWN_LAYOUTTYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>GETFH</c>		<tr>
	<c>		<td align="left">GETFH</td>
			<td align="left">
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_STALE		NFS4ERR_STALE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>ILLEGAL</c>		<tr>
	<c>		<td align="left">ILLEGAL</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_OP_ILLEGAL		NFS4ERR_OP_ILLEGAL
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>LAYOUTCOMMIT</c>		<tr>
	<c>		<td align="left">LAYOUTCOMMIT</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_ADMIN_REVOKED,		NFS4ERR_ADMIN_REVOKED,
	NFS4ERR_ATTRNOTSUPP,		NFS4ERR_ATTRNOTSUPP,
	NFS4ERR_BADIOMODE,		NFS4ERR_BADIOMODE,
	NFS4ERR_BADLAYOUT,		NFS4ERR_BADLAYOUT,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DELEG_REVOKED,		NFS4ERR_DELEG_REVOKED,
	NFS4ERR_EXPIRED,		NFS4ERR_EXPIRED,
	skipping to change at line 25510 ¶		skipping to change at line 25878 ¶
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_SYMLINK,		NFS4ERR_SYMLINK,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_UNKNOWN_LAYOUTTYPE,		NFS4ERR_UNKNOWN_LAYOUTTYPE,
	NFS4ERR_WRONG_CRED		NFS4ERR_WRONG_CRED
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>LAYOUTGET</c>		<tr>
	<c>		<td align="left">LAYOUTGET</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_ADMIN_REVOKED,		NFS4ERR_ADMIN_REVOKED,
	NFS4ERR_BADIOMODE,		NFS4ERR_BADIOMODE,
	NFS4ERR_BADLAYOUT,		NFS4ERR_BADLAYOUT,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DELEG_REVOKED,		NFS4ERR_DELEG_REVOKED,
	NFS4ERR_DQUOT,		NFS4ERR_DQUOT,
	skipping to change at line 25552 ¶		skipping to change at line 25919 ¶
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOOSMALL,		NFS4ERR_TOOSMALL,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_UNKNOWN_LAYOUTTYPE,		NFS4ERR_UNKNOWN_LAYOUTTYPE,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>LAYOUTRETURN</c>		<tr>
	<c>		<td align="left">LAYOUTRETURN</td>
			<td align="left">
	NFS4ERR_ADMIN_REVOKED,		NFS4ERR_ADMIN_REVOKED,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DELEG_REVOKED,		NFS4ERR_DELEG_REVOKED,
	NFS4ERR_EXPIRED,		NFS4ERR_EXPIRED,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_GRACE,		NFS4ERR_GRACE,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	skipping to change at line 25586 ¶		skipping to change at line 25952 ¶
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_UNKNOWN_LAYOUTTYPE,		NFS4ERR_UNKNOWN_LAYOUTTYPE,
	NFS4ERR_WRONG_CRED,		NFS4ERR_WRONG_CRED,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>LINK</c>		<tr>
	<c>		<td align="left">LINK</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_BADCHAR,		NFS4ERR_BADCHAR,
	NFS4ERR_BADNAME,		NFS4ERR_BADNAME,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DQUOT,		NFS4ERR_DQUOT,
	NFS4ERR_EXIST,		NFS4ERR_EXIST,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_FILE_OPEN,		NFS4ERR_FILE_OPEN,
	skipping to change at line 25627 ¶		skipping to change at line 25992 ¶
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_ROFS,		NFS4ERR_ROFS,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_SYMLINK,		NFS4ERR_SYMLINK,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONGSEC,		NFS4ERR_WRONGSEC,
	NFS4ERR_WRONG_TYPE,		NFS4ERR_WRONG_TYPE,
	NFS4ERR_XDEV		NFS4ERR_XDEV
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>LOCK</c>		<tr>
	<c>		<td align="left">LOCK</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_ADMIN_REVOKED,		NFS4ERR_ADMIN_REVOKED,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_RANGE,		NFS4ERR_BAD_RANGE,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DEADLOCK,		NFS4ERR_DEADLOCK,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DENIED,		NFS4ERR_DENIED,
	NFS4ERR_EXPIRED,		NFS4ERR_EXPIRED,
	skipping to change at line 25669 ¶		skipping to change at line 26033 ¶
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_ROFS,		NFS4ERR_ROFS,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_SYMLINK,		NFS4ERR_SYMLINK,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_CRED,		NFS4ERR_WRONG_CRED,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>LOCKT</c>		<tr>
	<c>		<td align="left">LOCKT</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_RANGE,		NFS4ERR_BAD_RANGE,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DENIED,		NFS4ERR_DENIED,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_GRACE,		NFS4ERR_GRACE,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_ISDIR,		NFS4ERR_ISDIR,
	skipping to change at line 25700 ¶		skipping to change at line 26063 ¶
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_ROFS,		NFS4ERR_ROFS,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_SYMLINK,		NFS4ERR_SYMLINK,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_CRED,		NFS4ERR_WRONG_CRED,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>LOCKU</c>		<tr>
	<c>		<td align="left">LOCKU</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_ADMIN_REVOKED,		NFS4ERR_ADMIN_REVOKED,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_RANGE,		NFS4ERR_BAD_RANGE,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_EXPIRED,		NFS4ERR_EXPIRED,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	skipping to change at line 25730 ¶		skipping to change at line 26092 ¶
	NFS4ERR_OLD_STATEID,		NFS4ERR_OLD_STATEID,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_CRED		NFS4ERR_WRONG_CRED
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>LOOKUP</c>		<tr>
	<c>		<td align="left">LOOKUP</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_BADCHAR,		NFS4ERR_BADCHAR,
	NFS4ERR_BADNAME,		NFS4ERR_BADNAME,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_IO,		NFS4ERR_IO,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	skipping to change at line 25761 ¶		skipping to change at line 26122 ¶
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_SYMLINK,		NFS4ERR_SYMLINK,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONGSEC		NFS4ERR_WRONGSEC
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>LOOKUPP</c>		<tr>
	<c>		<td align="left">LOOKUPP</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_IO,		NFS4ERR_IO,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOENT,		NFS4ERR_NOENT,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	NFS4ERR_NOTDIR,		NFS4ERR_NOTDIR,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_SYMLINK,		NFS4ERR_SYMLINK,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONGSEC		NFS4ERR_WRONGSEC
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>NVERIFY</c>		<tr>
	<c>		<td align="left">NVERIFY</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_ATTRNOTSUPP,		NFS4ERR_ATTRNOTSUPP,
	NFS4ERR_BADCHAR,		NFS4ERR_BADCHAR,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_GRACE,		NFS4ERR_GRACE,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_IO,		NFS4ERR_IO,
	skipping to change at line 25817 ¶		skipping to change at line 26176 ¶
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SAME,		NFS4ERR_SAME,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_UNKNOWN_LAYOUTTYPE,		NFS4ERR_UNKNOWN_LAYOUTTYPE,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>OPEN</c>		<tr>
	<c>		<td align="left">OPEN</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_ADMIN_REVOKED,		NFS4ERR_ADMIN_REVOKED,
	NFS4ERR_ATTRNOTSUPP,		NFS4ERR_ATTRNOTSUPP,
	NFS4ERR_BADCHAR,		NFS4ERR_BADCHAR,
	NFS4ERR_BADNAME,		NFS4ERR_BADNAME,
	NFS4ERR_BADOWNER,		NFS4ERR_BADOWNER,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	skipping to change at line 25870 ¶		skipping to change at line 26228 ¶
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_ROFS,		NFS4ERR_ROFS,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_SHARE_DENIED,		NFS4ERR_SHARE_DENIED,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_SYMLINK,		NFS4ERR_SYMLINK,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_UNSAFE_COMPOUND,		NFS4ERR_UNSAFE_COMPOUND,
	NFS4ERR_WRONGSEC,		NFS4ERR_WRONGSEC,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>OPEN_CONFIRM</c>		<tr>
	<c>		<td align="left">OPEN_CONFIRM</td>
			<td align="left">
	NFS4ERR_NOTSUPP		NFS4ERR_NOTSUPP
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>OPEN_DOWNGRADE</c>		<tr>
	<c>		<td align="left">OPEN_DOWNGRADE</td>
			<td align="left">
	NFS4ERR_ADMIN_REVOKED,		NFS4ERR_ADMIN_REVOKED,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_EXPIRED,		NFS4ERR_EXPIRED,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	skipping to change at line 25906 ¶		skipping to change at line 26262 ¶
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_ROFS,		NFS4ERR_ROFS,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_CRED		NFS4ERR_WRONG_CRED
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>OPENATTR</c>		<tr>
	<c>		<td align="left">OPENATTR</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DQUOT,		NFS4ERR_DQUOT,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_IO,		NFS4ERR_IO,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOENT,		NFS4ERR_NOENT,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	skipping to change at line 25936 ¶		skipping to change at line 26291 ¶
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_ROFS,		NFS4ERR_ROFS,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_UNSAFE_COMPOUND,		NFS4ERR_UNSAFE_COMPOUND,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>PUTFH</c>		<tr>
	<c>		<td align="left">PUTFH</td>
			<td align="left">
	NFS4ERR_BADHANDLE,		NFS4ERR_BADHANDLE,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONGSEC		NFS4ERR_WRONGSEC
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>PUTPUBFH</c>		<tr>
	<c>		<td align="left">PUTPUBFH</td>
			<td align="left">
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONGSEC		NFS4ERR_WRONGSEC
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>PUTROOTFH</c>		<tr>
	<c>		<td align="left">PUTROOTFH</td>
			<td align="left">
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONGSEC		NFS4ERR_WRONGSEC
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>READ</c>		<tr>
	<c>		<td align="left">READ</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_ADMIN_REVOKED,		NFS4ERR_ADMIN_REVOKED,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DELEG_REVOKED,		NFS4ERR_DELEG_REVOKED,
	NFS4ERR_EXPIRED,		NFS4ERR_EXPIRED,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_GRACE,		NFS4ERR_GRACE,
	skipping to change at line 26028 ¶		skipping to change at line 26379 ¶
	NFS4ERR_PNFS_NO_LAYOUT,		NFS4ERR_PNFS_NO_LAYOUT,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_SYMLINK,		NFS4ERR_SYMLINK,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>READDIR</c>		<tr>
	<c>		<td align="left">READDIR</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_COOKIE,		NFS4ERR_BAD_COOKIE,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_IO,		NFS4ERR_IO,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	skipping to change at line 26056 ¶		skipping to change at line 26406 ¶
	NFS4ERR_NOT_SAME,		NFS4ERR_NOT_SAME,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOOSMALL,		NFS4ERR_TOOSMALL,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>READLINK</c>		<tr>
	<c>		<td align="left">READLINK</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_IO,		NFS4ERR_IO,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>RECLAIM_COMPLETE</c>		<tr>
	<c>		<td align="left">RECLAIM_COMPLETE</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_COMPLETE_ALREADY,		NFS4ERR_COMPLETE_ALREADY,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_CRED,		NFS4ERR_WRONG_CRED,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>RELEASE_LOCKOWNER</c>		<tr>
	<c>		<td align="left">RELEASE_LOCKOWNER</td>
			<td align="left">
	NFS4ERR_NOTSUPP		NFS4ERR_NOTSUPP
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>REMOVE</c>		<tr>
	<c>		<td align="left">REMOVE</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_BADCHAR,		NFS4ERR_BADCHAR,
	NFS4ERR_BADNAME,		NFS4ERR_BADNAME,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_FILE_OPEN,		NFS4ERR_FILE_OPEN,
	NFS4ERR_GRACE,		NFS4ERR_GRACE,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	skipping to change at line 26146 ¶		skipping to change at line 26492 ¶
	NFS4ERR_NOTEMPTY,		NFS4ERR_NOTEMPTY,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_ROFS,		NFS4ERR_ROFS,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>RENAME</c>		<tr>
	<c>		<td align="left">RENAME</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_BADCHAR,		NFS4ERR_BADCHAR,
	NFS4ERR_BADNAME,		NFS4ERR_BADNAME,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DQUOT,		NFS4ERR_DQUOT,
	NFS4ERR_EXIST,		NFS4ERR_EXIST,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_FILE_OPEN,		NFS4ERR_FILE_OPEN,
	skipping to change at line 26185 ¶		skipping to change at line 26530 ¶
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_ROFS,		NFS4ERR_ROFS,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONGSEC,		NFS4ERR_WRONGSEC,
	NFS4ERR_XDEV		NFS4ERR_XDEV
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>RENEW</c>		<tr>
	<c>		<td align="left">RENEW</td>
			<td align="left">
	NFS4ERR_NOTSUPP		NFS4ERR_NOTSUPP
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>RESTOREFH</c>		<tr>
	<c>		<td align="left">RESTOREFH</td>
			<td align="left">
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONGSEC		NFS4ERR_WRONGSEC
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>SAVEFH</c>		<tr>
	<c>		<td align="left">SAVEFH</td>
			<td align="left">
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>SECINFO</c>		<tr>
	<c>		<td align="left">SECINFO</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_BADCHAR,		NFS4ERR_BADCHAR,
	NFS4ERR_BADNAME,		NFS4ERR_BADNAME,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NAMETOOLONG,		NFS4ERR_NAMETOOLONG,
	skipping to change at line 26260 ¶		skipping to change at line 26601 ¶
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	NFS4ERR_NOTDIR,		NFS4ERR_NOTDIR,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>SECINFO_NO_NAME</c>		<tr>
	<c>		<td align="left">SECINFO_NO_NAME</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOENT,		NFS4ERR_NOENT,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	NFS4ERR_NOTDIR,		NFS4ERR_NOTDIR,
	NFS4ERR_NOTSUPP,		NFS4ERR_NOTSUPP,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>SEQUENCE</c>		<tr>
	<c>		<td align="left">SEQUENCE</td>
			<td align="left">
	NFS4ERR_BADSESSION,		NFS4ERR_BADSESSION,
	NFS4ERR_BADSLOT,		NFS4ERR_BADSLOT,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_HIGH_SLOT,		NFS4ERR_BAD_HIGH_SLOT,
	NFS4ERR_CONN_NOT_BOUND_TO_SESSION,		NFS4ERR_CONN_NOT_BOUND_TO_SESSION,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SEQUENCE_POS,		NFS4ERR_SEQUENCE_POS,
	NFS4ERR_SEQ_FALSE_RETRY,		NFS4ERR_SEQ_FALSE_RETRY,
	NFS4ERR_SEQ_MISORDERED,		NFS4ERR_SEQ_MISORDERED,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>SET_SSV</c>		<tr>
	<c>		<td align="left">SET_SSV</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_SESSION_DIGEST,		NFS4ERR_BAD_SESSION_DIGEST,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>SETATTR</c>		<tr>
	<c>		<td align="left">SETATTR</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_ADMIN_REVOKED,		NFS4ERR_ADMIN_REVOKED,
	NFS4ERR_ATTRNOTSUPP,		NFS4ERR_ATTRNOTSUPP,
	NFS4ERR_BADCHAR,		NFS4ERR_BADCHAR,
	NFS4ERR_BADOWNER,		NFS4ERR_BADOWNER,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DELEG_REVOKED,		NFS4ERR_DELEG_REVOKED,
	skipping to change at line 26368 ¶		skipping to change at line 26705 ¶
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_ROFS,		NFS4ERR_ROFS,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_UNKNOWN_LAYOUTTYPE,		NFS4ERR_UNKNOWN_LAYOUTTYPE,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>SETCLIENTID</c>		<tr>
	<c>		<td align="left">SETCLIENTID</td>
			<td align="left">
	NFS4ERR_NOTSUPP		NFS4ERR_NOTSUPP
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>SETCLIENTID_CONFIRM</c>		<tr>
	<c>		<td align="left">SETCLIENTID_CONFIRM</td>
			<td align="left">
	NFS4ERR_NOTSUPP		NFS4ERR_NOTSUPP
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>TEST_STATEID</c>		<tr>
	<c>		<td align="left">TEST_STATEID</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>VERIFY</c>		<tr>
	<c>		<td align="left">VERIFY</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_ATTRNOTSUPP,		NFS4ERR_ATTRNOTSUPP,
	NFS4ERR_BADCHAR,		NFS4ERR_BADCHAR,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_GRACE,		NFS4ERR_GRACE,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_IO,		NFS4ERR_IO,
	skipping to change at line 26431 ¶		skipping to change at line 26764 ¶
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_UNKNOWN_LAYOUTTYPE,		NFS4ERR_UNKNOWN_LAYOUTTYPE,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>WANT_DELEGATION</c>		<tr>
	<c>		<td align="left">WANT_DELEGATION</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DELEG_ALREADY_WANTED,		NFS4ERR_DELEG_ALREADY_WANTED,
	NFS4ERR_FHEXPIRED,		NFS4ERR_FHEXPIRED,
	NFS4ERR_GRACE,		NFS4ERR_GRACE,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_IO,		NFS4ERR_IO,
	NFS4ERR_MOVED,		NFS4ERR_MOVED,
	NFS4ERR_NOFILEHANDLE,		NFS4ERR_NOFILEHANDLE,
	skipping to change at line 26462 ¶		skipping to change at line 26794 ¶
	NFS4ERR_RECLAIM_BAD,		NFS4ERR_RECLAIM_BAD,
	NFS4ERR_RECLAIM_CONFLICT,		NFS4ERR_RECLAIM_CONFLICT,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>WRITE</c>		<tr>
	<c>		<td align="left">WRITE</td>
			<td align="left">
	NFS4ERR_ACCESS,		NFS4ERR_ACCESS,
	NFS4ERR_ADMIN_REVOKED,		NFS4ERR_ADMIN_REVOKED,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DEADSESSION,		NFS4ERR_DEADSESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_DELEG_REVOKED,		NFS4ERR_DELEG_REVOKED,
	NFS4ERR_DQUOT,		NFS4ERR_DQUOT,
	NFS4ERR_EXPIRED,		NFS4ERR_EXPIRED,
	NFS4ERR_FBIG,		NFS4ERR_FBIG,
	skipping to change at line 26503 ¶		skipping to change at line 26834 ¶
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_ROFS,		NFS4ERR_ROFS,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_STALE,		NFS4ERR_STALE,
	NFS4ERR_SYMLINK,		NFS4ERR_SYMLINK,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />		</tbody>
	<c />		</table>
			</section>
	<!-- ENDOFTHEERRORTABLE -->
	<!-- DO NOT MOVE THIS OR THE ONE ABOVE LINE - IT MUST BE AT THE START OF TABLE -
	->
	</texttable>
	</section>
	<!-- When adding new errors above, add them to the next section under -->
	<!-- the appropriate operation; the next table for errors to -->
	<!-- operations is automatically generated. -->
	<section title="Callback Operations and Their Valid Errors">		<section numbered="true" toc="default">
	<t>		<name>Callback Operations and Their Valid Errors</name>
			<t>
	This section contains a table that gives the valid error returns		This section contains a table that gives the valid error returns
	for each callback operation. The error code NFS4_OK (indicating		for each callback operation. The error code NFS4_OK (indicating
	no error) is not listed but should be understood to be returnable		no error) is not listed but should be understood to be returnable
	by all callback operations with the exception of CB_ILLEGAL.		by all callback operations with the exception of CB_ILLEGAL.
	</t>		</t>
	<texttable anchor='cb_op_error_returns'>		<table anchor="cb_op_error_returns" align="center">
	<preamble> Valid Error Returns for Each Protocol		<name>Valid Error Returns for Each Protocol Callback Operation</name>
	Callback Operation </preamble>		<thead>
			<tr>
	<ttcol align='left'>Callback Operation</ttcol>		<th align="left">Callback Operation</th>
	<ttcol align='left'>Errors</ttcol>		<th align="left">Errors</th>
	<!-- DO NOT MOVE THIS OR THE NEXT LINE - IT MUST BE AT THE START OF TABLE -->		</tr>
	<!-- STARTOFTHEERRORTABLE -->		</thead>
			<tbody>
	<c>CB_GETATTR</c>		<tr>
	<c>		<td align="left">CB_GETATTR</td>
			<td align="left">
	NFS4ERR_BADHANDLE,		NFS4ERR_BADHANDLE,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CB_ILLEGAL</c>		<tr>
	<c>		<td align="left">CB_ILLEGAL</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_OP_ILLEGAL		NFS4ERR_OP_ILLEGAL
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CB_LAYOUTRECALL</c>		<tr>
	<c>		<td align="left">CB_LAYOUTRECALL</td>
			<td align="left">
	NFS4ERR_BADHANDLE,		NFS4ERR_BADHANDLE,
	NFS4ERR_BADIOMODE,		NFS4ERR_BADIOMODE,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_NOMATCHING_LAYOUT,		NFS4ERR_NOMATCHING_LAYOUT,
	NFS4ERR_NOTSUPP,		NFS4ERR_NOTSUPP,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_UNKNOWN_LAYOUTTYPE,		NFS4ERR_UNKNOWN_LAYOUTTYPE,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CB_NOTIFY</c>		<tr>
	<c>		<td align="left">CB_NOTIFY</td>
			<td align="left">
	NFS4ERR_BADHANDLE,		NFS4ERR_BADHANDLE,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_NOTSUPP,		NFS4ERR_NOTSUPP,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CB_NOTIFY_DEVICEID</c>		<tr>
	<c>		<td align="left">CB_NOTIFY_DEVICEID</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_NOTSUPP,		NFS4ERR_NOTSUPP,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CB_NOTIFY_LOCK</c>		<tr>
	<c>		<td align="left">CB_NOTIFY_LOCK</td>
			<td align="left">
	NFS4ERR_BADHANDLE,		NFS4ERR_BADHANDLE,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_NOTSUPP,		NFS4ERR_NOTSUPP,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CB_PUSH_DELEG</c>		<tr>
	<c>		<td align="left">CB_PUSH_DELEG</td>
			<td align="left">
	NFS4ERR_BADHANDLE,		NFS4ERR_BADHANDLE,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_NOTSUPP,		NFS4ERR_NOTSUPP,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REJECT_DELEG,		NFS4ERR_REJECT_DELEG,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS,		NFS4ERR_TOO_MANY_OPS,
	NFS4ERR_WRONG_TYPE		NFS4ERR_WRONG_TYPE
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CB_RECALL</c>		<tr>
	<c>		<td align="left">CB_RECALL</td>
			<td align="left">
	NFS4ERR_BADHANDLE,		NFS4ERR_BADHANDLE,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_STATEID,		NFS4ERR_BAD_STATEID,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CB_RECALL_ANY</c>		<tr>
	<c>		<td align="left">CB_RECALL_ANY</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CB_RECALLABLE_OBJ_AVAIL</c>		<tr>
	<c>		<td align="left">CB_RECALLABLE_OBJ_AVAIL</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_INVAL,		NFS4ERR_INVAL,
	NFS4ERR_NOTSUPP,		NFS4ERR_NOTSUPP,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CB_RECALL_SLOT</c>		<tr>
	<c>		<td align="left">CB_RECALL_SLOT</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_HIGH_SLOT,		NFS4ERR_BAD_HIGH_SLOT,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CB_SEQUENCE</c>		<tr>
	<c>		<td align="left">CB_SEQUENCE</td>
			<td align="left">
	NFS4ERR_BADSESSION,		NFS4ERR_BADSESSION,
	NFS4ERR_BADSLOT,		NFS4ERR_BADSLOT,
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_BAD_HIGH_SLOT,		NFS4ERR_BAD_HIGH_SLOT,
	NFS4ERR_CONN_NOT_BOUND_TO_SESSION,		NFS4ERR_CONN_NOT_BOUND_TO_SESSION,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SEQUENCE_POS,		NFS4ERR_SEQUENCE_POS,
	NFS4ERR_SEQ_FALSE_RETRY,		NFS4ERR_SEQ_FALSE_RETRY,
	NFS4ERR_SEQ_MISORDERED,		NFS4ERR_SEQ_MISORDERED,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />
	<c />
	<c>CB_WANTS_CANCELLED</c>		<tr>
	<c>		<td align="left">CB_WANTS_CANCELLED</td>
			<td align="left">
	NFS4ERR_BADXDR,		NFS4ERR_BADXDR,
	NFS4ERR_DELAY,		NFS4ERR_DELAY,
	NFS4ERR_NOTSUPP,		NFS4ERR_NOTSUPP,
	NFS4ERR_OP_NOT_IN_SESSION,		NFS4ERR_OP_NOT_IN_SESSION,
	NFS4ERR_REP_TOO_BIG,		NFS4ERR_REP_TOO_BIG,
	NFS4ERR_REP_TOO_BIG_TO_CACHE,		NFS4ERR_REP_TOO_BIG_TO_CACHE,
	NFS4ERR_REQ_TOO_BIG,		NFS4ERR_REQ_TOO_BIG,
	NFS4ERR_RETRY_UNCACHED_REP,		NFS4ERR_RETRY_UNCACHED_REP,
	NFS4ERR_SERVERFAULT,		NFS4ERR_SERVERFAULT,
	NFS4ERR_TOO_MANY_OPS		NFS4ERR_TOO_MANY_OPS
	</c>		</td>
			</tr>
	<c />		</tbody>
	<c />		</table>
			</section>
	<!-- ENDOFTHEERRORTABLE -->		<section numbered="true" toc="default">
	<!-- DO NOT MOVE THIS OR THE ONE ABOVE LINE - IT MUST BE AT THE START OF TABLE -		<name>Errors and the Operations That Use Them</name>
	->		<table anchor="error_op_returns" align="center">
	</texttable>		<name>Errors and the Operations That Use Them</name>
	</section>		<thead>
			<tr>
	<!-- INCLUDE THE AUTO GENERATED ERROR TO OP TABLE -->		<th align="left">Error</th>
	<section title="Errors and the Operations That Use Them">		<th align="left">Operations</th>
	<texttable anchor='error_op_returns'>		</tr>
	<ttcol align='left'>Error</ttcol>		</thead>
	<ttcol align='left'>Operations</ttcol>		<tbody>
			<tr>
	<c>NFS4ERR_ACCESS</c>		<td align="left">NFS4ERR_ACCESS</td>
	<c>		<td align="left">
	ACCESS,		ACCESS,
	COMMIT,		COMMIT,
	CREATE,		CREATE,
	GETATTR,		GETATTR,
	GET_DIR_DELEGATION,		GET_DIR_DELEGATION,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTGET,		LAYOUTGET,
	LINK,		LINK,
	LOCK,		LOCK,
	LOCKT,		LOCKT,
	skipping to change at line 26807 ¶		skipping to change at line 27120 ¶
	READ,		READ,
	READDIR,		READDIR,
	READLINK,		READLINK,
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SETATTR,		SETATTR,
	VERIFY,		VERIFY,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_ADMIN_REVOKED</c>		<tr>
	<c>		<td align="left">NFS4ERR_ADMIN_REVOKED</td>
			<td align="left">
	CLOSE,		CLOSE,
	DELEGRETURN,		DELEGRETURN,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTGET,		LAYOUTGET,
	LAYOUTRETURN,		LAYOUTRETURN,
	LOCK,		LOCK,
	LOCKU,		LOCKU,
	OPEN,		OPEN,
	OPEN_DOWNGRADE,		OPEN_DOWNGRADE,
	READ,		READ,
	SETATTR,		SETATTR,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_ATTRNOTSUPP</c>		<tr>
	<c>		<td align="left">NFS4ERR_ATTRNOTSUPP</td>
			<td align="left">
	CREATE,		CREATE,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	NVERIFY,		NVERIFY,
	OPEN,		OPEN,
	SETATTR,		SETATTR,
	VERIFY		VERIFY
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BACK_CHAN_BUSY</c>		<tr>
	<c>		<td align="left">NFS4ERR_BACK_CHAN_BUSY</td>
			<td align="left">
	DESTROY_SESSION		DESTROY_SESSION
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BADCHAR</c>		<tr>
	<c>		<td align="left">NFS4ERR_BADCHAR</td>
			<td align="left">
	CREATE,		CREATE,
	EXCHANGE_ID,		EXCHANGE_ID,
	LINK,		LINK,
	LOOKUP,		LOOKUP,
	NVERIFY,		NVERIFY,
	OPEN,		OPEN,
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	SECINFO,		SECINFO,
	SETATTR,		SETATTR,
	VERIFY		VERIFY
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BADHANDLE</c>		<tr>
	<c>		<td align="left">NFS4ERR_BADHANDLE</td>
			<td align="left">
	CB_GETATTR,		CB_GETATTR,
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	CB_NOTIFY,		CB_NOTIFY,
	CB_NOTIFY_LOCK,		CB_NOTIFY_LOCK,
	CB_PUSH_DELEG,		CB_PUSH_DELEG,
	CB_RECALL,		CB_RECALL,
	PUTFH		PUTFH
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BADIOMODE</c>		<tr>
	<c>		<td align="left">NFS4ERR_BADIOMODE</td>
			<td align="left">
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTGET		LAYOUTGET
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BADLAYOUT</c>		<tr>
	<c>		<td align="left">NFS4ERR_BADLAYOUT</td>
			<td align="left">
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTGET		LAYOUTGET
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BADNAME</c>		<tr>
	<c>		<td align="left">NFS4ERR_BADNAME</td>
			<td align="left">
	CREATE,		CREATE,
	LINK,		LINK,
	LOOKUP,		LOOKUP,
	OPEN,		OPEN,
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	SECINFO		SECINFO
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BADOWNER</c>		<tr>
	<c>		<td align="left">NFS4ERR_BADOWNER</td>
			<td align="left">
	CREATE,		CREATE,
	OPEN,		OPEN,
	SETATTR		SETATTR
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BADSESSION</c>		<tr>
	<c>		<td align="left">NFS4ERR_BADSESSION</td>
			<td align="left">
	BIND_CONN_TO_SESSION,		BIND_CONN_TO_SESSION,
	CB_SEQUENCE,		CB_SEQUENCE,
	DESTROY_SESSION,		DESTROY_SESSION,
	SEQUENCE		SEQUENCE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BADSLOT</c>		<tr>
	<c>		<td align="left">NFS4ERR_BADSLOT</td>
			<td align="left">
	CB_SEQUENCE,		CB_SEQUENCE,
	SEQUENCE		SEQUENCE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BADTYPE</c>		<tr>
	<c>		<td align="left">NFS4ERR_BADTYPE</td>
			<td align="left">
	CREATE		CREATE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BADXDR</c>		<tr>
	<c>		<td align="left">NFS4ERR_BADXDR</td>
			<td align="left">
	ACCESS,		ACCESS,
	BACKCHANNEL_CTL,		BACKCHANNEL_CTL,
	BIND_CONN_TO_SESSION,		BIND_CONN_TO_SESSION,
	CB_GETATTR,		CB_GETATTR,
	CB_ILLEGAL,		CB_ILLEGAL,
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	CB_NOTIFY,		CB_NOTIFY,
	CB_NOTIFY_DEVICEID,		CB_NOTIFY_DEVICEID,
	CB_NOTIFY_LOCK,		CB_NOTIFY_LOCK,
	CB_PUSH_DELEG,		CB_PUSH_DELEG,
	skipping to change at line 27002 ¶		skipping to change at line 27315 ¶
	RENAME,		RENAME,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SEQUENCE,		SEQUENCE,
	SETATTR,		SETATTR,
	SET_SSV,		SET_SSV,
	TEST_STATEID,		TEST_STATEID,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BAD_COOKIE</c>		<tr>
	<c>		<td align="left">NFS4ERR_BAD_COOKIE</td>
			<td align="left">
	GETDEVICELIST,		GETDEVICELIST,
	READDIR		READDIR
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BAD_HIGH_SLOT</c>		<tr>
	<c>		<td align="left">NFS4ERR_BAD_HIGH_SLOT</td>
			<td align="left">
	CB_RECALL_SLOT,		CB_RECALL_SLOT,
	CB_SEQUENCE,		CB_SEQUENCE,
	SEQUENCE		SEQUENCE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BAD_RANGE</c>		<tr>
	<c>		<td align="left">NFS4ERR_BAD_RANGE</td>
			<td align="left">
	LOCK,		LOCK,
	LOCKT,		LOCKT,
	LOCKU		LOCKU
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BAD_SESSION_DIGEST</c>		<tr>
	<c>		<td align="left">NFS4ERR_BAD_SESSION_DIGEST</td>
			<td align="left">
	BIND_CONN_TO_SESSION,		BIND_CONN_TO_SESSION,
	SET_SSV		SET_SSV
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_BAD_STATEID</c>		<tr>
	<c>		<td align="left">NFS4ERR_BAD_STATEID</td>
			<td align="left">
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	CB_NOTIFY,		CB_NOTIFY,
	CB_NOTIFY_LOCK,		CB_NOTIFY_LOCK,
	CB_RECALL,		CB_RECALL,
	CLOSE,		CLOSE,
	DELEGRETURN,		DELEGRETURN,
	FREE_STATEID,		FREE_STATEID,
	LAYOUTGET,		LAYOUTGET,
	LAYOUTRETURN,		LAYOUTRETURN,
	LOCK,		LOCK,
	LOCKU,		LOCKU,
	OPEN,		OPEN,
	OPEN_DOWNGRADE,		OPEN_DOWNGRADE,
	READ,		READ,
	SETATTR,		SETATTR,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_CB_PATH_DOWN</c>		<tr>
	<c>		<td align="left">NFS4ERR_CB_PATH_DOWN</td>
			<td align="left">
	DESTROY_SESSION		DESTROY_SESSION
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_CLID_INUSE</c>		<tr>
	<c>		<td align="left">NFS4ERR_CLID_INUSE</td>
			<td align="left">
	CREATE_SESSION,		CREATE_SESSION,
	EXCHANGE_ID		EXCHANGE_ID
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_CLIENTID_BUSY</c>		<tr>
	<c>		<td align="left">NFS4ERR_CLIENTID_BUSY</td>
			<td align="left">
	DESTROY_CLIENTID		DESTROY_CLIENTID
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_COMPLETE_ALREADY</c>		<tr>
	<c>		<td align="left">NFS4ERR_COMPLETE_ALREADY</td>
			<td align="left">
	RECLAIM_COMPLETE		RECLAIM_COMPLETE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_CONN_NOT_BOUND_TO_SESSION</c>		<tr>
	<c>		<td align="left">NFS4ERR_CONN_NOT_BOUND_TO_SESSION</td>
			<td align="left">
	CB_SEQUENCE,		CB_SEQUENCE,
	DESTROY_SESSION,		DESTROY_SESSION,
	SEQUENCE		SEQUENCE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_DEADLOCK</c>		<tr>
	<c>		<td align="left">NFS4ERR_DEADLOCK</td>
			<td align="left">
	LOCK		LOCK
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_DEADSESSION</c>		<tr>
	<c>		<td align="left">NFS4ERR_DEADSESSION</td>
			<td align="left">
	ACCESS,		ACCESS,
	BACKCHANNEL_CTL,		BACKCHANNEL_CTL,
	BIND_CONN_TO_SESSION,		BIND_CONN_TO_SESSION,
	CLOSE,		CLOSE,
	COMMIT,		COMMIT,
	CREATE,		CREATE,
	CREATE_SESSION,		CREATE_SESSION,
	DELEGPURGE,		DELEGPURGE,
	DELEGRETURN,		DELEGRETURN,
	DESTROY_CLIENTID,		DESTROY_CLIENTID,
	skipping to change at line 27159 ¶		skipping to change at line 27472 ¶
	SAVEFH,		SAVEFH,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SEQUENCE,		SEQUENCE,
	SETATTR,		SETATTR,
	SET_SSV,		SET_SSV,
	TEST_STATEID,		TEST_STATEID,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_DELAY</c>		<tr>
	<c>		<td align="left">NFS4ERR_DELAY</td>
			<td align="left">
	ACCESS,		ACCESS,
	BACKCHANNEL_CTL,		BACKCHANNEL_CTL,
	BIND_CONN_TO_SESSION,		BIND_CONN_TO_SESSION,
	CB_GETATTR,		CB_GETATTR,
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	CB_NOTIFY,		CB_NOTIFY,
	CB_NOTIFY_DEVICEID,		CB_NOTIFY_DEVICEID,
	CB_NOTIFY_LOCK,		CB_NOTIFY_LOCK,
	CB_PUSH_DELEG,		CB_PUSH_DELEG,
	CB_RECALL,		CB_RECALL,
	skipping to change at line 27225 ¶		skipping to change at line 27538 ¶
	RENAME,		RENAME,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SEQUENCE,		SEQUENCE,
	SETATTR,		SETATTR,
	SET_SSV,		SET_SSV,
	TEST_STATEID,		TEST_STATEID,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_DELEG_ALREADY_WANTED</c>		<tr>
	<c>		<td align="left">NFS4ERR_DELEG_ALREADY_WANTED</td>
			<td align="left">
	OPEN,		OPEN,
	WANT_DELEGATION		WANT_DELEGATION
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_DELEG_REVOKED</c>		<tr>
	<c>		<td align="left">NFS4ERR_DELEG_REVOKED</td>
			<td align="left">
	DELEGRETURN,		DELEGRETURN,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTGET,		LAYOUTGET,
	LAYOUTRETURN,		LAYOUTRETURN,
	OPEN,		OPEN,
	READ,		READ,
	SETATTR,		SETATTR,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_DENIED</c>		<tr>
	<c>		<td align="left">NFS4ERR_DENIED</td>
			<td align="left">
	LOCK,		LOCK,
	LOCKT		LOCKT
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_DIRDELEG_UNAVAIL</c>		<tr>
	<c>		<td align="left">NFS4ERR_DIRDELEG_UNAVAIL</td>
			<td align="left">
	GET_DIR_DELEGATION		GET_DIR_DELEGATION
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_DQUOT</c>		<tr>
	<c>		<td align="left">NFS4ERR_DQUOT</td>
			<td align="left">
	CREATE,		CREATE,
	LAYOUTGET,		LAYOUTGET,
	LINK,		LINK,
	OPEN,		OPEN,
	OPENATTR,		OPENATTR,
	RENAME,		RENAME,
	SETATTR,		SETATTR,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_ENCR_ALG_UNSUPP</c>		<tr>
	<c>		<td align="left">NFS4ERR_ENCR_ALG_UNSUPP</td>
			<td align="left">
	EXCHANGE_ID		EXCHANGE_ID
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_EXIST</c>		<tr>
	<c>		<td align="left">NFS4ERR_EXIST</td>
			<td align="left">
	CREATE,		CREATE,
	LINK,		LINK,
	OPEN,		OPEN,
	RENAME		RENAME
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_EXPIRED</c>		<tr>
	<c>		<td align="left">NFS4ERR_EXPIRED</td>
			<td align="left">
	CLOSE,		CLOSE,
	DELEGRETURN,		DELEGRETURN,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTRETURN,		LAYOUTRETURN,
	LOCK,		LOCK,
	LOCKU,		LOCKU,
	OPEN,		OPEN,
	OPEN_DOWNGRADE,		OPEN_DOWNGRADE,
	READ,		READ,
	SETATTR,		SETATTR,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_FBIG</c>		<tr>
	<c>		<td align="left">NFS4ERR_FBIG</td>
			<td align="left">
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	OPEN,		OPEN,
	SETATTR,		SETATTR,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_FHEXPIRED</c>		<tr>
	<c>		<td align="left">NFS4ERR_FHEXPIRED</td>
			<td align="left">
	ACCESS,		ACCESS,
	CLOSE,		CLOSE,
	COMMIT,		COMMIT,
	CREATE,		CREATE,
	DELEGRETURN,		DELEGRETURN,
	GETATTR,		GETATTR,
	GETDEVICELIST,		GETDEVICELIST,
	GETFH,		GETFH,
	GET_DIR_DELEGATION,		GET_DIR_DELEGATION,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	skipping to change at line 27362 ¶		skipping to change at line 27675 ¶
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	RESTOREFH,		RESTOREFH,
	SAVEFH,		SAVEFH,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SETATTR,		SETATTR,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_FILE_OPEN</c>		<tr>
	<c>		<td align="left">NFS4ERR_FILE_OPEN</td>
			<td align="left">
	LINK,		LINK,
	REMOVE,		REMOVE,
	RENAME		RENAME
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_GRACE</c>		<tr>
	<c>		<td align="left">NFS4ERR_GRACE</td>
			<td align="left">
	GETATTR,		GETATTR,
	GET_DIR_DELEGATION,		GET_DIR_DELEGATION,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTGET,		LAYOUTGET,
	LAYOUTRETURN,		LAYOUTRETURN,
	LINK,		LINK,
	LOCK,		LOCK,
	LOCKT,		LOCKT,
	NVERIFY,		NVERIFY,
	OPEN,		OPEN,
	READ,		READ,
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	SETATTR,		SETATTR,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_HASH_ALG_UNSUPP</c>		<tr>
	<c>		<td align="left">NFS4ERR_HASH_ALG_UNSUPP</td>
			<td align="left">
	EXCHANGE_ID		EXCHANGE_ID
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_INVAL</c>		<tr>
	<c>		<td align="left">NFS4ERR_INVAL</td>
			<td align="left">
	ACCESS,		ACCESS,
	BACKCHANNEL_CTL,		BACKCHANNEL_CTL,
	BIND_CONN_TO_SESSION,		BIND_CONN_TO_SESSION,
	CB_GETATTR,		CB_GETATTR,
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	CB_NOTIFY,		CB_NOTIFY,
	CB_NOTIFY_DEVICEID,		CB_NOTIFY_DEVICEID,
	CB_PUSH_DELEG,		CB_PUSH_DELEG,
	CB_RECALLABLE_OBJ_AVAIL,		CB_RECALLABLE_OBJ_AVAIL,
	CB_RECALL_ANY,		CB_RECALL_ANY,
	skipping to change at line 27449 ¶		skipping to change at line 27762 ¶
	RECLAIM_COMPLETE,		RECLAIM_COMPLETE,
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SETATTR,		SETATTR,
	SET_SSV,		SET_SSV,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_IO</c>		<tr>
	<c>		<td align="left">NFS4ERR_IO</td>
			<td align="left">
	ACCESS,		ACCESS,
	COMMIT,		COMMIT,
	CREATE,		CREATE,
	GETATTR,		GETATTR,
	GETDEVICELIST,		GETDEVICELIST,
	GET_DIR_DELEGATION,		GET_DIR_DELEGATION,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTGET,		LAYOUTGET,
	LINK,		LINK,
	LOOKUP,		LOOKUP,
	skipping to change at line 27478 ¶		skipping to change at line 27791 ¶
	OPENATTR,		OPENATTR,
	READ,		READ,
	READDIR,		READDIR,
	READLINK,		READLINK,
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	SETATTR,		SETATTR,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_ISDIR</c>		<tr>
	<c>		<td align="left">NFS4ERR_ISDIR</td>
			<td align="left">
	COMMIT,		COMMIT,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTRETURN,		LAYOUTRETURN,
	LINK,		LINK,
	LOCK,		LOCK,
	LOCKT,		LOCKT,
	OPEN,		OPEN,
	READ,		READ,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_LAYOUTTRYLATER</c>		<tr>
	<c>		<td align="left">NFS4ERR_LAYOUTTRYLATER</td>
			<td align="left">
	LAYOUTGET		LAYOUTGET
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_LAYOUTUNAVAILABLE</c>		<tr>
	<c>		<td align="left">NFS4ERR_LAYOUTUNAVAILABLE</td>
			<td align="left">
	LAYOUTGET		LAYOUTGET
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_LOCKED</c>		<tr>
	<c>		<td align="left">NFS4ERR_LOCKED</td>
			<td align="left">
	LAYOUTGET,		LAYOUTGET,
	READ,		READ,
	SETATTR,		SETATTR,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_LOCKS_HELD</c>		<tr>
	<c>		<td align="left">NFS4ERR_LOCKS_HELD</td>
			<td align="left">
	CLOSE,		CLOSE,
	FREE_STATEID		FREE_STATEID
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_LOCK_NOTSUPP</c>		<tr>
	<c>		<td align="left">NFS4ERR_LOCK_NOTSUPP</td>
			<td align="left">
	LOCK		LOCK
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_LOCK_RANGE</c>		<tr>
	<c>		<td align="left">NFS4ERR_LOCK_RANGE</td>
			<td align="left">
	LOCK,		LOCK,
	LOCKT,		LOCKT,
	LOCKU		LOCKU
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_MLINK</c>		<tr>
	<c>		<td align="left">NFS4ERR_MLINK</td>
			<td align="left">
	CREATE,		CREATE,
	LINK,		LINK,
	RENAME		RENAME
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_MOVED</c>		<tr>
	<c>		<td align="left">NFS4ERR_MOVED</td>
			<td align="left">
	ACCESS,		ACCESS,
	CLOSE,		CLOSE,
	COMMIT,		COMMIT,
	CREATE,		CREATE,
	DELEGRETURN,		DELEGRETURN,
	GETATTR,		GETATTR,
	GETFH,		GETFH,
	GET_DIR_DELEGATION,		GET_DIR_DELEGATION,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTGET,		LAYOUTGET,
	skipping to change at line 27592 ¶		skipping to change at line 27905 ¶
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	RESTOREFH,		RESTOREFH,
	SAVEFH,		SAVEFH,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SETATTR,		SETATTR,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_NAMETOOLONG</c>		<tr>
	<c>		<td align="left">NFS4ERR_NAMETOOLONG</td>
			<td align="left">
	CREATE,		CREATE,
	LINK,		LINK,
	LOOKUP,		LOOKUP,
	OPEN,		OPEN,
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	SECINFO		SECINFO
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_NOENT</c>		<tr>
	<c>		<td align="left">NFS4ERR_NOENT</td>
			<td align="left">
	BACKCHANNEL_CTL,		BACKCHANNEL_CTL,
	CREATE_SESSION,		CREATE_SESSION,
	EXCHANGE_ID,		EXCHANGE_ID,
	GETDEVICEINFO,		GETDEVICEINFO,
	LOOKUP,		LOOKUP,
	LOOKUPP,		LOOKUPP,
	OPEN,		OPEN,
	OPENATTR,		OPENATTR,
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME		SECINFO_NO_NAME
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_NOFILEHANDLE</c>		<tr>
	<c>		<td align="left">NFS4ERR_NOFILEHANDLE</td>
			<td align="left">
	ACCESS,		ACCESS,
	CLOSE,		CLOSE,
	COMMIT,		COMMIT,
	CREATE,		CREATE,
	DELEGRETURN,		DELEGRETURN,
	GETATTR,		GETATTR,
	GETDEVICELIST,		GETDEVICELIST,
	GETFH,		GETFH,
	GET_DIR_DELEGATION,		GET_DIR_DELEGATION,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	skipping to change at line 27665 ¶		skipping to change at line 27978 ¶
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	RESTOREFH,		RESTOREFH,
	SAVEFH,		SAVEFH,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SETATTR,		SETATTR,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_NOMATCHING_LAYOUT</c>		<tr>
	<c>		<td align="left">NFS4ERR_NOMATCHING_LAYOUT</td>
			<td align="left">
	CB_LAYOUTRECALL		CB_LAYOUTRECALL
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_NOSPC</c>		<tr>
	<c>		<td align="left">NFS4ERR_NOSPC</td>
			<td align="left">
	CREATE,		CREATE,
	CREATE_SESSION,		CREATE_SESSION,
	LAYOUTGET,		LAYOUTGET,
	LINK,		LINK,
	OPEN,		OPEN,
	OPENATTR,		OPENATTR,
	RENAME,		RENAME,
	SETATTR,		SETATTR,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_NOTDIR</c>		<tr>
	<c>		<td align="left">NFS4ERR_NOTDIR</td>
			<td align="left">
	CREATE,		CREATE,
	GET_DIR_DELEGATION,		GET_DIR_DELEGATION,
	LINK,		LINK,
	LOOKUP,		LOOKUP,
	LOOKUPP,		LOOKUPP,
	OPEN,		OPEN,
	READDIR,		READDIR,
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME		SECINFO_NO_NAME
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_NOTEMPTY</c>		<tr>
	<c>		<td align="left">NFS4ERR_NOTEMPTY</td>
			<td align="left">
	REMOVE,		REMOVE,
	RENAME		RENAME
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_NOTSUPP</c>		<tr>
	<c>		<td align="left">NFS4ERR_NOTSUPP</td>
			<td align="left">
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	CB_NOTIFY,		CB_NOTIFY,
	CB_NOTIFY_DEVICEID,		CB_NOTIFY_DEVICEID,
	CB_NOTIFY_LOCK,		CB_NOTIFY_LOCK,
	CB_PUSH_DELEG,		CB_PUSH_DELEG,
	CB_RECALLABLE_OBJ_AVAIL,		CB_RECALLABLE_OBJ_AVAIL,
	CB_WANTS_CANCELLED,		CB_WANTS_CANCELLED,
	DELEGPURGE,		DELEGPURGE,
	DELEGRETURN,		DELEGRETURN,
	GETDEVICEINFO,		GETDEVICEINFO,
	skipping to change at line 27742 ¶		skipping to change at line 28055 ¶
	LAYOUTRETURN,		LAYOUTRETURN,
	LINK,		LINK,
	OPENATTR,		OPENATTR,
	OPEN_CONFIRM,		OPEN_CONFIRM,
	RELEASE_LOCKOWNER,		RELEASE_LOCKOWNER,
	RENEW,		RENEW,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SETCLIENTID,		SETCLIENTID,
	SETCLIENTID_CONFIRM,		SETCLIENTID_CONFIRM,
	WANT_DELEGATION		WANT_DELEGATION
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_NOT_ONLY_OP</c>		<tr>
	<c>		<td align="left">NFS4ERR_NOT_ONLY_OP</td>
			<td align="left">
	BIND_CONN_TO_SESSION,		BIND_CONN_TO_SESSION,
	CREATE_SESSION,		CREATE_SESSION,
	DESTROY_CLIENTID,		DESTROY_CLIENTID,
	DESTROY_SESSION,		DESTROY_SESSION,
	EXCHANGE_ID		EXCHANGE_ID
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_NOT_SAME</c>		<tr>
	<c>		<td align="left">NFS4ERR_NOT_SAME</td>
			<td align="left">
	EXCHANGE_ID,		EXCHANGE_ID,
	GETDEVICELIST,		GETDEVICELIST,
	READDIR,		READDIR,
	VERIFY		VERIFY
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_NO_GRACE</c>		<tr>
	<c>		<td align="left">NFS4ERR_NO_GRACE</td>
			<td align="left">
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTRETURN,		LAYOUTRETURN,
	LOCK,		LOCK,
	OPEN,		OPEN,
	WANT_DELEGATION		WANT_DELEGATION
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_OLD_STATEID</c>		<tr>
	<c>		<td align="left">NFS4ERR_OLD_STATEID</td>
			<td align="left">
	CLOSE,		CLOSE,
	DELEGRETURN,		DELEGRETURN,
	FREE_STATEID,		FREE_STATEID,
	LAYOUTGET,		LAYOUTGET,
	LAYOUTRETURN,		LAYOUTRETURN,
	LOCK,		LOCK,
	LOCKU,		LOCKU,
	OPEN,		OPEN,
	OPEN_DOWNGRADE,		OPEN_DOWNGRADE,
	READ,		READ,
	SETATTR,		SETATTR,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_OPENMODE</c>		<tr>
	<c>		<td align="left">NFS4ERR_OPENMODE</td>
			<td align="left">
	LAYOUTGET,		LAYOUTGET,
	LOCK,		LOCK,
	READ,		READ,
	SETATTR,		SETATTR,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_OP_ILLEGAL</c>		<tr>
	<c>		<td align="left">NFS4ERR_OP_ILLEGAL</td>
			<td align="left">
	CB_ILLEGAL,		CB_ILLEGAL,
	ILLEGAL		ILLEGAL
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_OP_NOT_IN_SESSION</c>		<tr>
	<c>		<td align="left">NFS4ERR_OP_NOT_IN_SESSION</td>
			<td align="left">
	ACCESS,		ACCESS,
	BACKCHANNEL_CTL,		BACKCHANNEL_CTL,
	CB_GETATTR,		CB_GETATTR,
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	CB_NOTIFY,		CB_NOTIFY,
	CB_NOTIFY_DEVICEID,		CB_NOTIFY_DEVICEID,
	CB_NOTIFY_LOCK,		CB_NOTIFY_LOCK,
	CB_PUSH_DELEG,		CB_PUSH_DELEG,
	CB_RECALL,		CB_RECALL,
	CB_RECALLABLE_OBJ_AVAIL,		CB_RECALLABLE_OBJ_AVAIL,
	skipping to change at line 27873 ¶		skipping to change at line 28186 ¶
	RESTOREFH,		RESTOREFH,
	SAVEFH,		SAVEFH,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SETATTR,		SETATTR,
	SET_SSV,		SET_SSV,
	TEST_STATEID,		TEST_STATEID,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_PERM</c>		<tr>
	<c>		<td align="left">NFS4ERR_PERM</td>
			<td align="left">
	CREATE,		CREATE,
	OPEN,		OPEN,
	SETATTR		SETATTR
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_PNFS_IO_HOLE</c>		<tr>
	<c>		<td align="left">NFS4ERR_PNFS_IO_HOLE</td>
			<td align="left">
	READ,		READ,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_PNFS_NO_LAYOUT</c>		<tr>
	<c>		<td align="left">NFS4ERR_PNFS_NO_LAYOUT</td>
			<td align="left">
	READ,		READ,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_RECALLCONFLICT</c>		<tr>
	<c>		<td align="left">NFS4ERR_RECALLCONFLICT</td>
			<td align="left">
	LAYOUTGET,		LAYOUTGET,
	WANT_DELEGATION		WANT_DELEGATION
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_RECLAIM_BAD</c>		<tr>
	<c>		<td align="left">NFS4ERR_RECLAIM_BAD</td>
			<td align="left">
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LOCK,		LOCK,
	OPEN,		OPEN,
	WANT_DELEGATION		WANT_DELEGATION
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_RECLAIM_CONFLICT</c>		<tr>
	<c>		<td align="left">NFS4ERR_RECLAIM_CONFLICT</td>
			<td align="left">
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LOCK,		LOCK,
	OPEN,		OPEN,
	WANT_DELEGATION		WANT_DELEGATION
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_REJECT_DELEG</c>		<tr>
	<c>		<td align="left">NFS4ERR_REJECT_DELEG</td>
			<td align="left">
	CB_PUSH_DELEG		CB_PUSH_DELEG
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_REP_TOO_BIG</c>		<tr>
	<c>		<td align="left">NFS4ERR_REP_TOO_BIG</td>
			<td align="left">
	ACCESS,		ACCESS,
	BACKCHANNEL_CTL,		BACKCHANNEL_CTL,
	BIND_CONN_TO_SESSION,		BIND_CONN_TO_SESSION,
	CB_GETATTR,		CB_GETATTR,
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	CB_NOTIFY,		CB_NOTIFY,
	CB_NOTIFY_DEVICEID,		CB_NOTIFY_DEVICEID,
	CB_NOTIFY_LOCK,		CB_NOTIFY_LOCK,
	CB_PUSH_DELEG,		CB_PUSH_DELEG,
	CB_RECALL,		CB_RECALL,
	skipping to change at line 28001 ¶		skipping to change at line 28314 ¶
	SAVEFH,		SAVEFH,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SEQUENCE,		SEQUENCE,
	SETATTR,		SETATTR,
	SET_SSV,		SET_SSV,
	TEST_STATEID,		TEST_STATEID,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_REP_TOO_BIG_TO_CACHE</c>		<tr>
	<c>		<td align="left">NFS4ERR_REP_TOO_BIG_TO_CACHE</td>
			<td align="left">
	ACCESS,		ACCESS,
	BACKCHANNEL_CTL,		BACKCHANNEL_CTL,
	BIND_CONN_TO_SESSION,		BIND_CONN_TO_SESSION,
	CB_GETATTR,		CB_GETATTR,
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	CB_NOTIFY,		CB_NOTIFY,
	CB_NOTIFY_DEVICEID,		CB_NOTIFY_DEVICEID,
	CB_NOTIFY_LOCK,		CB_NOTIFY_LOCK,
	CB_PUSH_DELEG,		CB_PUSH_DELEG,
	CB_RECALL,		CB_RECALL,
	skipping to change at line 28069 ¶		skipping to change at line 28382 ¶
	SAVEFH,		SAVEFH,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SEQUENCE,		SEQUENCE,
	SETATTR,		SETATTR,
	SET_SSV,		SET_SSV,
	TEST_STATEID,		TEST_STATEID,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_REQ_TOO_BIG</c>		<tr>
	<c>		<td align="left">NFS4ERR_REQ_TOO_BIG</td>
			<td align="left">
	ACCESS,		ACCESS,
	BACKCHANNEL_CTL,		BACKCHANNEL_CTL,
	BIND_CONN_TO_SESSION,		BIND_CONN_TO_SESSION,
	CB_GETATTR,		CB_GETATTR,
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	CB_NOTIFY,		CB_NOTIFY,
	CB_NOTIFY_DEVICEID,		CB_NOTIFY_DEVICEID,
	CB_NOTIFY_LOCK,		CB_NOTIFY_LOCK,
	CB_PUSH_DELEG,		CB_PUSH_DELEG,
	CB_RECALL,		CB_RECALL,
	skipping to change at line 28137 ¶		skipping to change at line 28450 ¶
	SAVEFH,		SAVEFH,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SEQUENCE,		SEQUENCE,
	SETATTR,		SETATTR,
	SET_SSV,		SET_SSV,
	TEST_STATEID,		TEST_STATEID,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_RETRY_UNCACHED_REP</c>		<tr>
	<c>		<td align="left">NFS4ERR_RETRY_UNCACHED_REP</td>
			<td align="left">
	ACCESS,		ACCESS,
	BACKCHANNEL_CTL,		BACKCHANNEL_CTL,
	BIND_CONN_TO_SESSION,		BIND_CONN_TO_SESSION,
	CB_GETATTR,		CB_GETATTR,
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	CB_NOTIFY,		CB_NOTIFY,
	CB_NOTIFY_DEVICEID,		CB_NOTIFY_DEVICEID,
	CB_NOTIFY_LOCK,		CB_NOTIFY_LOCK,
	CB_PUSH_DELEG,		CB_PUSH_DELEG,
	CB_RECALL,		CB_RECALL,
	skipping to change at line 28205 ¶		skipping to change at line 28518 ¶
	SAVEFH,		SAVEFH,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SEQUENCE,		SEQUENCE,
	SETATTR,		SETATTR,
	SET_SSV,		SET_SSV,
	TEST_STATEID,		TEST_STATEID,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_ROFS</c>		<tr>
	<c>		<td align="left">NFS4ERR_ROFS</td>
			<td align="left">
	CREATE,		CREATE,
	LINK,		LINK,
	LOCK,		LOCK,
	LOCKT,		LOCKT,
	OPEN,		OPEN,
	OPENATTR,		OPENATTR,
	OPEN_DOWNGRADE,		OPEN_DOWNGRADE,
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	SETATTR,		SETATTR,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_SAME</c>		<tr>
	<c>		<td align="left">NFS4ERR_SAME</td>
			<td align="left">
	NVERIFY		NVERIFY
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_SEQUENCE_POS</c>		<tr>
	<c>		<td align="left">NFS4ERR_SEQUENCE_POS</td>
			<td align="left">
	CB_SEQUENCE,		CB_SEQUENCE,
	SEQUENCE		SEQUENCE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_SEQ_FALSE_RETRY</c>		<tr>
	<c>		<td align="left">NFS4ERR_SEQ_FALSE_RETRY</td>
			<td align="left">
	CB_SEQUENCE,		CB_SEQUENCE,
	SEQUENCE		SEQUENCE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_SEQ_MISORDERED</c>		<tr>
	<c>		<td align="left">NFS4ERR_SEQ_MISORDERED</td>
			<td align="left">
	CB_SEQUENCE,		CB_SEQUENCE,
	CREATE_SESSION,		CREATE_SESSION,
	SEQUENCE		SEQUENCE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_SERVERFAULT</c>		<tr>
	<c>		<td align="left">NFS4ERR_SERVERFAULT</td>
			<td align="left">
	ACCESS,		ACCESS,
	BIND_CONN_TO_SESSION,		BIND_CONN_TO_SESSION,
	CB_GETATTR,		CB_GETATTR,
	CB_NOTIFY,		CB_NOTIFY,
	CB_NOTIFY_DEVICEID,		CB_NOTIFY_DEVICEID,
	CB_NOTIFY_LOCK,		CB_NOTIFY_LOCK,
	CB_PUSH_DELEG,		CB_PUSH_DELEG,
	CB_RECALL,		CB_RECALL,
	CB_RECALLABLE_OBJ_AVAIL,		CB_RECALLABLE_OBJ_AVAIL,
	CB_WANTS_CANCELLED,		CB_WANTS_CANCELLED,
	skipping to change at line 28314 ¶		skipping to change at line 28627 ¶
	RENAME,		RENAME,
	RESTOREFH,		RESTOREFH,
	SAVEFH,		SAVEFH,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SETATTR,		SETATTR,
	TEST_STATEID,		TEST_STATEID,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_SHARE_DENIED</c>		<tr>
	<c>		<td align="left">NFS4ERR_SHARE_DENIED</td>
			<td align="left">
	OPEN		OPEN
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_STALE</c>		<tr>
	<c>		<td align="left">NFS4ERR_STALE</td>
			<td align="left">
	ACCESS,		ACCESS,
	CLOSE,		CLOSE,
	COMMIT,		COMMIT,
	CREATE,		CREATE,
	DELEGRETURN,		DELEGRETURN,
	GETATTR,		GETATTR,
	GETFH,		GETFH,
	GET_DIR_DELEGATION,		GET_DIR_DELEGATION,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTGET,		LAYOUTGET,
	skipping to change at line 28363 ¶		skipping to change at line 28676 ¶
	REMOVE,		REMOVE,
	RENAME,		RENAME,
	RESTOREFH,		RESTOREFH,
	SAVEFH,		SAVEFH,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SETATTR,		SETATTR,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_STALE_CLIENTID</c>		<tr>
	<c>		<td align="left">NFS4ERR_STALE_CLIENTID</td>
			<td align="left">
	CREATE_SESSION,		CREATE_SESSION,
	DESTROY_CLIENTID,		DESTROY_CLIENTID,
	DESTROY_SESSION		DESTROY_SESSION
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_SYMLINK</c>		<tr>
	<c>		<td align="left">NFS4ERR_SYMLINK</td>
			<td align="left">
	COMMIT,		COMMIT,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LINK,		LINK,
	LOCK,		LOCK,
	LOCKT,		LOCKT,
	LOOKUP,		LOOKUP,
	LOOKUPP,		LOOKUPP,
	OPEN,		OPEN,
	READ,		READ,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_TOOSMALL</c>		<tr>
	<c>		<td align="left">NFS4ERR_TOOSMALL</td>
			<td align="left">
	CREATE_SESSION,		CREATE_SESSION,
	GETDEVICEINFO,		GETDEVICEINFO,
	LAYOUTGET,		LAYOUTGET,
	READDIR		READDIR
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_TOO_MANY_OPS</c>		<tr>
	<c>		<td align="left">NFS4ERR_TOO_MANY_OPS</td>
			<td align="left">
	ACCESS,		ACCESS,
	BACKCHANNEL_CTL,		BACKCHANNEL_CTL,
	BIND_CONN_TO_SESSION,		BIND_CONN_TO_SESSION,
	CB_GETATTR,		CB_GETATTR,
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	CB_NOTIFY,		CB_NOTIFY,
	CB_NOTIFY_DEVICEID,		CB_NOTIFY_DEVICEID,
	CB_NOTIFY_LOCK,		CB_NOTIFY_LOCK,
	CB_PUSH_DELEG,		CB_PUSH_DELEG,
	CB_RECALL,		CB_RECALL,
	skipping to change at line 28466 ¶		skipping to change at line 28779 ¶
	SAVEFH,		SAVEFH,
	SECINFO,		SECINFO,
	SECINFO_NO_NAME,		SECINFO_NO_NAME,
	SEQUENCE,		SEQUENCE,
	SETATTR,		SETATTR,
	SET_SSV,		SET_SSV,
	TEST_STATEID,		TEST_STATEID,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_UNKNOWN_LAYOUTTYPE</c>		<tr>
	<c>		<td align="left">NFS4ERR_UNKNOWN_LAYOUTTYPE</td>
			<td align="left">
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	GETDEVICEINFO,		GETDEVICEINFO,
	GETDEVICELIST,		GETDEVICELIST,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTGET,		LAYOUTGET,
	LAYOUTRETURN,		LAYOUTRETURN,
	NVERIFY,		NVERIFY,
	SETATTR,		SETATTR,
	VERIFY		VERIFY
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_UNSAFE_COMPOUND</c>		<tr>
	<c>		<td align="left">NFS4ERR_UNSAFE_COMPOUND</td>
			<td align="left">
	CREATE,		CREATE,
	OPEN,		OPEN,
	OPENATTR		OPENATTR
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_WRONGSEC</c>		<tr>
	<c>		<td align="left">NFS4ERR_WRONGSEC</td>
			<td align="left">
	LINK,		LINK,
	LOOKUP,		LOOKUP,
	LOOKUPP,		LOOKUPP,
	OPEN,		OPEN,
	PUTFH,		PUTFH,
	PUTPUBFH,		PUTPUBFH,
	PUTROOTFH,		PUTROOTFH,
	RENAME,		RENAME,
	RESTOREFH		RESTOREFH
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_WRONG_CRED</c>		<tr>
	<c>		<td align="left">NFS4ERR_WRONG_CRED</td>
			<td align="left">
	CLOSE,		CLOSE,
	CREATE_SESSION,		CREATE_SESSION,
	DELEGPURGE,		DELEGPURGE,
	DELEGRETURN,		DELEGRETURN,
	DESTROY_CLIENTID,		DESTROY_CLIENTID,
	DESTROY_SESSION,		DESTROY_SESSION,
	FREE_STATEID,		FREE_STATEID,
	LAYOUTCOMMIT,		LAYOUTCOMMIT,
	LAYOUTRETURN,		LAYOUTRETURN,
	LOCK,		LOCK,
	LOCKT,		LOCKT,
	LOCKU,		LOCKU,
	OPEN_DOWNGRADE,		OPEN_DOWNGRADE,
	RECLAIM_COMPLETE		RECLAIM_COMPLETE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_WRONG_TYPE</c>		<tr>
	<c>		<td align="left">NFS4ERR_WRONG_TYPE</td>
			<td align="left">
	CB_LAYOUTRECALL,		CB_LAYOUTRECALL,
	CB_PUSH_DELEG,		CB_PUSH_DELEG,
	COMMIT,		COMMIT,
	GETATTR,		GETATTR,
	LAYOUTGET,		LAYOUTGET,
	LAYOUTRETURN,		LAYOUTRETURN,
	LINK,		LINK,
	LOCK,		LOCK,
	LOCKT,		LOCKT,
	NVERIFY,		NVERIFY,
	OPEN,		OPEN,
	OPENATTR,		OPENATTR,
	READ,		READ,
	READLINK,		READLINK,
	RECLAIM_COMPLETE,		RECLAIM_COMPLETE,
	SETATTR,		SETATTR,
	VERIFY,		VERIFY,
	WANT_DELEGATION,		WANT_DELEGATION,
	WRITE		WRITE
	</c>		</td>
	<c />		</tr>
	<c />
	<c>NFS4ERR_XDEV</c>		<tr>
	<c>		<td align="left">NFS4ERR_XDEV</td>
			<td align="left">
	LINK,		LINK,
	RENAME		RENAME
	</c>		</td>
	<c />		</tr>
	<c />		</tbody>
			</table>
	</texttable>		</section>
	</section>		</section>
			<section anchor="nfsv41procedures" numbered="true" toc="default">
	</section>		<name>NFSv4.1 Procedures</name>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<t>
	$ -->		Both procedures, NULL and COMPOUND, <bcp14>MUST</bcp14> be implemented.
	<!-- Copyright (C) The IETF Trust (2007) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="nfsv41procedures" title="NFSv4.1 Procedures">
	<t>
	Both procedures, NULL and COMPOUND, MUST be implemented.
	</t>		</t>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="PROC_NULL" numbered="true" toc="default">
	$ -->		<name>Procedure 0: NULL - No Operation</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="PROC_NULL_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="PROC_NULL" title="Procedure 0: NULL - No Operation" >		<sourcecode type="xdr"><![CDATA[
			void;]]></sourcecode>
	<section toc="exclude" anchor="PROC_NULL_ARGUMENTS" title="ARGUMENTS">		</section>
	<figure>		<section toc="exclude" anchor="PROC_NULL_RESULTS" numbered="true">
	<artwork>		<name>RESULTS</name>
	void;		<sourcecode type="xdr"><![CDATA[
	</artwork>		void;]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="PROC_NULL_DESCRIPTION" numbered="true">
			<name>DESCRIPTION</name>
	<section toc="exclude" anchor="PROC_NULL_RESULTS" title="RESULTS">		<t>
	<figure>
	<artwork>
	void;
	</artwork>
	</figure>
	</section>
	<section toc="exclude" anchor="PROC_NULL_DESCRIPTION" title="DESCRIPTION">
	<t>
	This is the standard NULL procedure with the standard void argument and		This is the standard NULL procedure with the standard void argument and
	void response.		void response.
	This procedure has no functionality associated with it. Because of		This procedure has no functionality associated with it. Because of
	this, it is sometimes used to measure the overhead of processing a		this, it is sometimes used to measure the overhead of processing a
	service request. Therefore, the server SHOULD ensure that no		service request. Therefore, the server <bcp14>SHOULD</bcp14> ensure that no
	unnecessary work is done in servicing this procedure.		unnecessary work is done in servicing this procedure.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="PROC_NULL_ERRORS" title="ERRORS">		<section toc="exclude" anchor="PROC_NULL_ERRORS" numbered="true">
	<t>		<name>ERRORS</name>
			<t>
	None.		None.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_COMPOUND" numbered="true" toc="default">
	$ -->		<name>Procedure 1: COMPOUND - Compound Operations</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_COMPOUND_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_COMPOUND" title="Procedure 1: COMPOUND - Compound Operations		<sourcecode type="xdr"><![CDATA[
	" >
	<section toc="exclude" anchor="OP_COMPOUND_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	enum nfs_opnum4 {		enum nfs_opnum4 {
	OP_ACCESS = 3,		OP_ACCESS = 3,
	OP_CLOSE = 4,		OP_CLOSE = 4,
	OP_COMMIT = 5,		OP_COMMIT = 5,
	OP_CREATE = 6,		OP_CREATE = 6,
	OP_DELEGPURGE = 7,		OP_DELEGPURGE = 7,
	OP_DELEGRETURN = 8,		OP_DELEGRETURN = 8,
	OP_GETATTR = 9,		OP_GETATTR = 9,
	OP_GETFH = 10,		OP_GETFH = 10,
	OP_LINK = 11,		OP_LINK = 11,
	skipping to change at line 28681 ¶		skipping to change at line 28980 ¶
	OP_LAYOUTRETURN = 51,		OP_LAYOUTRETURN = 51,
	OP_SECINFO_NO_NAME = 52,		OP_SECINFO_NO_NAME = 52,
	OP_SEQUENCE = 53,		OP_SEQUENCE = 53,
	OP_SET_SSV = 54,		OP_SET_SSV = 54,
	OP_TEST_STATEID = 55,		OP_TEST_STATEID = 55,
	OP_WANT_DELEGATION = 56,		OP_WANT_DELEGATION = 56,
	OP_DESTROY_CLIENTID = 57,		OP_DESTROY_CLIENTID = 57,
	OP_RECLAIM_COMPLETE = 58,		OP_RECLAIM_COMPLETE = 58,
	OP_ILLEGAL = 10044		OP_ILLEGAL = 10044
	};		};
	</artwork>
	</figure>
	<figure>
	<artwork>
	union nfs_argop4 switch (nfs_opnum4 argop) {		union nfs_argop4 switch (nfs_opnum4 argop) {
	case OP_ACCESS: ACCESS4args opaccess;		case OP_ACCESS: ACCESS4args opaccess;
	case OP_CLOSE: CLOSE4args opclose;		case OP_CLOSE: CLOSE4args opclose;
	case OP_COMMIT: COMMIT4args opcommit;		case OP_COMMIT: COMMIT4args opcommit;
	case OP_CREATE: CREATE4args opcreate;		case OP_CREATE: CREATE4args opcreate;
	case OP_DELEGPURGE: DELEGPURGE4args opdelegpurge;		case OP_DELEGPURGE: DELEGPURGE4args opdelegpurge;
	case OP_DELEGRETURN: DELEGRETURN4args opdelegreturn;		case OP_DELEGRETURN: DELEGRETURN4args opdelegreturn;
	case OP_GETATTR: GETATTR4args opgetattr;		case OP_GETATTR: GETATTR4args opgetattr;
	case OP_GETFH: void;		case OP_GETFH: void;
	case OP_LINK: LINK4args oplink;		case OP_LINK: LINK4args oplink;
	skipping to change at line 28790 ¶		skipping to change at line 29086 ¶
	DESTROY_CLIENTID4args		DESTROY_CLIENTID4args
	opdestroy_clientid;		opdestroy_clientid;
	case OP_RECLAIM_COMPLETE:		case OP_RECLAIM_COMPLETE:
	RECLAIM_COMPLETE4args		RECLAIM_COMPLETE4args
	opreclaim_complete;		opreclaim_complete;
	/* Operations not new to NFSv4.1 */		/* Operations not new to NFSv4.1 */
	case OP_ILLEGAL: void;		case OP_ILLEGAL: void;
	};		};
	</artwork>
	</figure>
	<figure>
	<artwork>
	struct COMPOUND4args {		struct COMPOUND4args {
	utf8str_cs tag;		utf8str_cs tag;
	uint32_t minorversion;		uint32_t minorversion;
	nfs_argop4 argarray&lt;>;		nfs_argop4 argarray<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
			<section toc="exclude" anchor="OP_COMPOUND_RESULTS" numbered="true">
	</section>		<name>RESULTS</name>
			<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_COMPOUND_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	union nfs_resop4 switch (nfs_opnum4 resop) {		union nfs_resop4 switch (nfs_opnum4 resop) {
	case OP_ACCESS: ACCESS4res opaccess;		case OP_ACCESS: ACCESS4res opaccess;
	case OP_CLOSE: CLOSE4res opclose;		case OP_CLOSE: CLOSE4res opclose;
	case OP_COMMIT: COMMIT4res opcommit;		case OP_COMMIT: COMMIT4res opcommit;
	case OP_CREATE: CREATE4res opcreate;		case OP_CREATE: CREATE4res opcreate;
	case OP_DELEGPURGE: DELEGPURGE4res opdelegpurge;		case OP_DELEGPURGE: DELEGPURGE4res opdelegpurge;
	case OP_DELEGRETURN: DELEGRETURN4res opdelegreturn;		case OP_DELEGRETURN: DELEGRETURN4res opdelegreturn;
	case OP_GETATTR: GETATTR4res opgetattr;		case OP_GETATTR: GETATTR4res opgetattr;
	case OP_GETFH: GETFH4res opgetfh;		case OP_GETFH: GETFH4res opgetfh;
	case OP_LINK: LINK4res oplink;		case OP_LINK: LINK4res oplink;
	skipping to change at line 28921 ¶		skipping to change at line 29210 ¶
	DESTROY_CLIENTID4res		DESTROY_CLIENTID4res
	opdestroy_clientid;		opdestroy_clientid;
	case OP_RECLAIM_COMPLETE:		case OP_RECLAIM_COMPLETE:
	RECLAIM_COMPLETE4res		RECLAIM_COMPLETE4res
	opreclaim_complete;		opreclaim_complete;
	/* Operations not new to NFSv4.1 */		/* Operations not new to NFSv4.1 */
	case OP_ILLEGAL: ILLEGAL4res opillegal;		case OP_ILLEGAL: ILLEGAL4res opillegal;
	};		};
	</artwork>
	</figure>
	<figure>
	<artwork>
	struct COMPOUND4res {		struct COMPOUND4res {
	nfsstat4 status;		nfsstat4 status;
	utf8str_cs tag;		utf8str_cs tag;
	nfs_resop4 resarray&lt;>;		nfs_resop4 resarray<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
			<section toc="exclude" anchor="OP_COMPOUND_DESCRIPTION" numbered="true">
	</section>		<name>DESCRIPTION</name>
			<t>
	<section toc="exclude" anchor="OP_COMPOUND_DESCRIPTION" title="DESCRIPTION">
	<t>
	The COMPOUND procedure is used to combine one or more NFSv4		The COMPOUND procedure is used to combine one or more NFSv4
	operations into a		operations into a
	single RPC request. The server interprets each of the operations in		single RPC request. The server interprets each of the operations in
	turn. If an operation is executed by the server and the status of that		turn. If an operation is executed by the server and the status of that
	operation is NFS4_OK, then the next operation in the COMPOUND		operation is NFS4_OK, then the next operation in the COMPOUND
	procedure is executed. The server continues this process until there		procedure is executed. The server continues this process until there
	are no more operations to be executed or until one of the operations has a		are no more operations to be executed or until one of the operations has a
	status value other than NFS4_OK.		status value other than NFS4_OK.
	</t>		</t>
	<t>		<t>
	In the processing of the COMPOUND procedure, the server may find that		In the processing of the COMPOUND procedure, the server may find that
	it does not have the available resources to execute any or all of the		it does not have the available resources to execute any or all of the
	operations within the COMPOUND sequence. See		operations within the COMPOUND sequence. See
	<xref target="COMPOUND_Sizing_Issues" /> for a more detailed discussion.		<xref target="COMPOUND_Sizing_Issues" format="default"/> for a more detail
	</t>		ed discussion.
	<t>		</t>
			<t>
	The server will generally choose between two methods of decoding the		The server will generally choose between two methods of decoding the
	client's request. The first would be the traditional one-pass XDR		client's request. The first would be the traditional one-pass XDR
	decode. If there is an XDR decoding error in this case, the RPC XDR		decode. If there is an XDR decoding error in this case, the RPC XDR
	decode error would be returned. The second method would be to make an		decode error would be returned. The second method would be to make an
	initial pass to decode the basic COMPOUND request and then to XDR		initial pass to decode the basic COMPOUND request and then to XDR
	decode the individual operations; the most interesting is the decode		decode the individual operations; the most interesting is the decode
	of attributes. In this case, the server may encounter an XDR decode		of attributes. In this case, the server may encounter an XDR decode
	error during the second pass. If it does, the server would return		error during the second pass. If it does, the server would return
	the error NFS4ERR_BADXDR to signify the decode error.		the error NFS4ERR_BADXDR to signify the decode error.
	</t>		</t>
	<t>		<t>
	The COMPOUND arguments contain a "minorversion" field. For NFSv4.1,		The COMPOUND arguments contain a "minorversion" field. For NFSv4.1,
	the value for this field is 1. If the server receives		the value for this field is 1. If the server receives
	a COMPOUND procedure with a minorversion field value that it does not		a COMPOUND procedure with a minorversion field value that it does not
	support, the server MUST return an error of		support, the server <bcp14>MUST</bcp14> return an error of
	NFS4ERR_MINOR_VERS_MISMATCH and a zero-length resultdata array.		NFS4ERR_MINOR_VERS_MISMATCH and a zero-length resultdata array.
	</t>		</t>
	<t>		<t>
	Contained within the COMPOUND results is a "status" field. If the		Contained within the COMPOUND results is a "status" field. If the
	results array length is non-zero, this status must be equivalent to		results array length is non-zero, this status must be equivalent to
	the status of the last operation that was executed within the COMPOUND		the status of the last operation that was executed within the COMPOUND
	procedure. Therefore, if an operation incurred an error then the		procedure. Therefore, if an operation incurred an error then the
	"status" value will be the same error value as is being returned for		"status" value will be the same error value as is being returned for
	the operation that failed.		the operation that failed.
	</t>		</t>
	<t>		<t>
	Note that operations zero and one are not defined for the		Note that operations zero and one are not defined for the
	COMPOUND procedure. Operation 2 is not defined and is reserved for		COMPOUND procedure. Operation 2 is not defined and is reserved for
	future definition and use with minor versioning. If the server		future definition and use with minor versioning. If the server
	receives an operation array that contains operation 2 and the		receives an operation array that contains operation 2 and the
	minorversion field has a value of zero, an error of		minorversion field has a value of zero, an error of
	NFS4ERR_OP_ILLEGAL, as described in the next paragraph, is returned to		NFS4ERR_OP_ILLEGAL, as described in the next paragraph, is returned to
	the client. If an operation array contains an operation 2 and the		the client. If an operation array contains an operation 2 and the
	minorversion field is non-zero and the server does not support the		minorversion field is non-zero and the server does not support the
	minor version, the server returns an error of		minor version, the server returns an error of
	NFS4ERR_MINOR_VERS_MISMATCH. Therefore, the		NFS4ERR_MINOR_VERS_MISMATCH. Therefore, the
	NFS4ERR_MINOR_VERS_MISMATCH error takes precedence over all other		NFS4ERR_MINOR_VERS_MISMATCH error takes precedence over all other
	errors.		errors.
	</t>		</t>
	<t>		<t>
	It is possible that the server receives a request that contains an		It is possible that the server receives a request that contains an
	operation that is less than the first legal operation (OP_ACCESS) or		operation that is less than the first legal operation (OP_ACCESS) or
	greater than the last legal operation (OP_RELEASE_LOCKOWNER). In this		greater than the last legal operation (OP_RELEASE_LOCKOWNER). In this
	case, the server's response will encode the opcode OP_ILLEGAL rather		case, the server's response will encode the opcode OP_ILLEGAL rather
	than the illegal opcode of the request. The status field in the		than the illegal opcode of the request. The status field in the
	ILLEGAL return results will be set to NFS4ERR_OP_ILLEGAL. The COMPOUND		ILLEGAL return results will be set to NFS4ERR_OP_ILLEGAL. The COMPOUND
	procedure's return results will also be NFS4ERR_OP_ILLEGAL.		procedure's return results will also be NFS4ERR_OP_ILLEGAL.
	</t>		</t>
	<t>		<t>
	The definition of the "tag" in the request is left to the implementor.		The definition of the "tag" in the request is left to the implementor.
	It may be used to summarize the content of the Compound request for		It may be used to summarize the content of the Compound request for
	the benefit of packet-sniffers and engineers debugging		the benefit of packet-sniffers and engineers debugging
	implementations. However, the value of "tag" in the response SHOULD		implementations. However, the value of "tag" in the response <bcp14>SHOUL D</bcp14>
	be the same value as provided in the request. This applies to the tag		be the same value as provided in the request. This applies to the tag
	field of the CB_COMPOUND procedure as well.		field of the CB_COMPOUND procedure as well.
	</t>		</t>
	<section toc="exclude" anchor="current_filehandle_stateid"		<section toc="exclude" anchor="current_filehandle_stateid" numbered="t
	title="Current Filehandle and Stateid">		rue">
	<t>		<name>Current Filehandle and Stateid</name>
			<t>
	The COMPOUND procedure offers a simple environment for the		The COMPOUND procedure offers a simple environment for the
	execution of the operations specified by the client. The first		execution of the operations specified by the client. The first
	two relate to the filehandle while the second two relate to the		two relate to the filehandle while the second two relate to the
	current stateid.		current stateid.
	</t>		</t>
	<section toc="exclude" anchor="current_filehandle" title="Current		<section toc="exclude" anchor="current_filehandle" numbered="true">
	Filehandle">		<name>Current Filehandle</name>
	<t>		<t>
	The current and saved filehandles are used throughout		The current and saved filehandles are used throughout
	the protocol. Most operations implicitly use		the protocol. Most operations implicitly use
	the current filehandle as an argument, and many set		the current filehandle as an argument, and many set
	the current filehandle as part of the results.		the current filehandle as part of the results.
	The combination of client-specified sequences		The combination of client-specified sequences
	of operations and current and saved filehandle		of operations and current and saved filehandle
	arguments and results allows for greater protocol		arguments and results allows for greater protocol
	flexibility. The best or easiest example of current		flexibility. The best or easiest example of current
	filehandle usage is a sequence like the following:		filehandle usage is a sequence like the following:
	</t>		</t>
	<t>		<figure anchor="curfh_example">
	<figure anchor='curfh_example'>		<sourcecode type="nfsv4compound"><![CDATA[
	<artwork>
	PUTFH fh1 {fh1}		PUTFH fh1 {fh1}
	LOOKUP "compA" {fh2}		LOOKUP "compA" {fh2}
	GETATTR {fh2}		GETATTR {fh2}
	LOOKUP "compB" {fh3}		LOOKUP "compB" {fh3}
	GETATTR {fh3}		GETATTR {fh3}
	LOOKUP "compC" {fh4}		LOOKUP "compC" {fh4}
	GETATTR {fh4}		GETATTR {fh4}
	GETFH		GETFH]]></sourcecode>
	</artwork>		</figure>
	</figure>		<t>
	</t>		In this example, the PUTFH (<xref target="OP_PUTFH" format="default"/>) op
	<t>		eration explicitly sets the current
	In this example, the PUTFH (<xref target="OP_PUTFH"/>) operation explicitl
	y sets the current
	filehandle value while the result of each LOOKUP operation sets		filehandle value while the result of each LOOKUP operation sets
	the current filehandle value to the resultant file system		the current filehandle value to the resultant file system
	object. Also, the client is able to insert GETATTR operations		object. Also, the client is able to insert GETATTR operations
	using the current filehandle as an argument.		using the current filehandle as an argument.
	</t>		</t>
	<t>		<t>
	The PUTROOTFH (<xref target="OP_PUTROOTFH"/>) and		The PUTROOTFH (<xref target="OP_PUTROOTFH" format="default"/>) and
	PUTPUBFH (<xref target="OP_PUTPUBFH"/>) operations also set the		PUTPUBFH (<xref target="OP_PUTPUBFH" format="default"/>) operations also
			set the
	current filehandle. The above example would replace "PUTFH fh1" with		current filehandle. The above example would replace "PUTFH fh1" with
	PUTROOTFH or PUTPUBFH with no filehandle argument in order to		PUTROOTFH or PUTPUBFH with no filehandle argument in order to
	achieve the same effect (on the assumption that "compA" is directly		achieve the same effect (on the assumption that "compA" is directly
	below the root of the namespace).		below the root of the namespace).
	</t>		</t>
	<t>		<t>
	Along with the current filehandle, there is a saved filehandle.		Along with the current filehandle, there is a saved filehandle.
	While the current filehandle is set as the result of		While the current filehandle is set as the result of
	operations like LOOKUP, the saved filehandle must be set		operations like LOOKUP, the saved filehandle must be set
	directly with the use of the SAVEFH operation. The SAVEFH		directly with the use of the SAVEFH operation. The SAVEFH
	operation copies the current filehandle value to the saved		operation copies the current filehandle value to the saved
	value. The saved filehandle value is used in combination with		value. The saved filehandle value is used in combination with
	the current filehandle value for the LINK and RENAME		the current filehandle value for the LINK and RENAME
	operations. The RESTOREFH operation will copy the saved filehandle value to the current filehandle value; as a result, the		operations. The RESTOREFH operation will copy the saved filehandle value to the current filehandle value; as a result, the
	saved filehandle value may be used a sort of "scratch" area for		saved filehandle value may be used a sort of "scratch" area for
	the client's series of operations.		the client's series of operations.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="current_stateid" numbered="true">
	<section toc="exclude" anchor="current_stateid" title="Current Stateid">		<name>Current Stateid</name>
	<t>		<t>
	With NFSv4.1, additions of a current stateid and a saved stateid		With NFSv4.1, additions of a current stateid and a saved stateid
	have been made to the COMPOUND processing environment; this		have been made to the COMPOUND processing environment; this
	allows for the passing of stateids between operations. There		allows for the passing of stateids between operations. There
	are no changes to the syntax of the protocol, only changes to		are no changes to the syntax of the protocol, only changes to
	the semantics of a few operations.		the semantics of a few operations.
	</t>		</t>
	<t>		<t>
	A "current stateid" is the stateid that is associated		A "current stateid" is the stateid that is associated
	with the current filehandle. The current stateid		with the current filehandle. The current stateid
	may only be changed by an operation that modifies		may only be changed by an operation that modifies
	the current filehandle or returns a stateid. If an		the current filehandle or returns a stateid. If an
	operation returns a stateid, it MUST set the current		operation returns a stateid, it <bcp14>MUST</bcp14> set the current
	stateid to the returned value. If an operation sets		stateid to the returned value. If an operation sets
	the current filehandle but does not return a stateid,		the current filehandle but does not return a stateid,
	the current stateid MUST be set to the all-zeros		the current stateid <bcp14>MUST</bcp14> be set to the all-zeros
	special stateid, i.e., (seqid, other) = (0, 0).		special stateid, i.e., (seqid, other) = (0, 0).
	If an operation uses a stateid as an argument but does		If an operation uses a stateid as an argument but does
	not return a stateid, the current stateid MUST NOT be		not return a stateid, the current stateid <bcp14>MUST NOT</bcp14> be
	changed.		changed.
	For example, PUTFH, PUTROOTFH, and PUTPUBFH		For example, PUTFH, PUTROOTFH, and PUTPUBFH
	will change the current server state from {ocfh,		will change the current server state from {ocfh,
	(osid)} to {cfh, (0, 0)}, while LOCK will change the current		(osid)} to {cfh, (0, 0)}, while LOCK will change the current
	state from {cfh, (osid} to {cfh, (nsid)}. Operations like		state from {cfh, (osid} to {cfh, (nsid)}. Operations like
	LOOKUP that transform a current filehandle and		LOOKUP that transform a current filehandle and
	component name into a new current filehandle will also		component name into a new current filehandle will also
	change the current state to {0, 0}. The SAVEFH		change the current state to {0, 0}. The SAVEFH
	and RESTOREFH operations will save and restore both		and RESTOREFH operations will save and restore both
	the current filehandle and the current stateid as a set.		the current filehandle and the current stateid as a set.
	</t>		</t>
			<t>
	<t>
	The following example is the common case of a simple READ		The following example is the common case of a simple READ
	operation with a normal stateid showing that the PUTFH		operation with a normal stateid showing that the PUTFH
	initializes the current stateid to (0, 0). The subsequent READ		initializes the current stateid to (0, 0). The subsequent READ
	with stateid (sid1) leaves the current stateid unchanged.		with stateid (sid1) leaves the current stateid unchanged.
	</t>		</t>
	<figure anchor='csid_example1'>		<figure anchor="csid_example1">
	<artwork>		<sourcecode type="nfsv4compound"><![CDATA[
	PUTFH fh1 - -> {fh1, (0, 0)}		PUTFH fh1 - -> {fh1, (0, 0)}
	READ (sid1), 0, 1024 {fh1, (0, 0)} -> {fh1, (0, 0)}		READ (sid1), 0, 1024 {fh1, (0, 0)} -> {fh1, (0, 0)}]]></sourcecode>
	</artwork>		</figure>
	</figure>		<t>
	<t>
	This next example performs an OPEN with the root		This next example performs an OPEN with the root
	filehandle and, as a result, generates stateid (sid1). The next		filehandle and, as a result, generates stateid (sid1). The next
	operation specifies the READ with the argument stateid set such		operation specifies the READ with the argument stateid set such
	that (seqid, other) are equal to (1, 0),		that (seqid, other) are equal to (1, 0),
	but the current stateid set by the previous operation is		but the current stateid set by the previous operation is
	actually used when the operation is evaluated. This allows correct		actually used when the operation is evaluated. This allows correct
	interaction with any existing, potentially conflicting,		interaction with any existing, potentially conflicting,
	locks.		locks.
	</t>		</t>
	<figure anchor='csid_example2'>		<figure anchor="csid_example2">
	<artwork>		<sourcecode type="nfsv4compound"><![CDATA[
	PUTROOTFH - -> {fh1, (0, 0)}		PUTROOTFH - -> {fh1, (0, 0)}
	OPEN "compA" {fh1, (0, 0)} -> {fh2, (sid1)}		OPEN "compA" {fh1, (0, 0)} -> {fh2, (sid1)}
	READ (1, 0), 0, 1024 {fh2, (sid1)} -> {fh2, (sid1)}		READ (1, 0), 0, 1024 {fh2, (sid1)} -> {fh2, (sid1)}
	CLOSE (1, 0) {fh2, (sid1)} -> {fh2, (sid2)}		CLOSE (1, 0) {fh2, (sid1)} -> {fh2, (sid2)}]]></sourcecode>
	</artwork>		</figure>
	</figure>		<t>
	<t>
	This next example is similar to the second in how		This next example is similar to the second in how
	it passes the stateid sid2 generated by the LOCK		it passes the stateid sid2 generated by the LOCK
	operation to the next READ operation. This allows		operation to the next READ operation. This allows
	the client to explicitly surround a single I/O		the client to explicitly surround a single I/O
	operation with a lock and its appropriate stateid to		operation with a lock and its appropriate stateid to
	guarantee correctness with other client locks. The		guarantee correctness with other client locks. The
	example also shows how SAVEFH and RESTOREFH can		example also shows how SAVEFH and RESTOREFH can
	save and later reuse a filehandle and stateid, passing them as the		save and later reuse a filehandle and stateid, passing them as the
	current filehandle and stateid to a READ operation.		current filehandle and stateid to a READ operation.
	</t>		</t>
	<figure anchor='csid_example3'>		<figure anchor="csid_example3">
	<artwork>		<sourcecode type="nfsv4compound"><![CDATA[
	PUTFH fh1 - -> {fh1, (0, 0)}		PUTFH fh1 - -> {fh1, (0, 0)}
	LOCK 0, 1024, (sid1) {fh1, (sid1)} -> {fh1, (sid2)}		LOCK 0, 1024, (sid1) {fh1, (sid1)} -> {fh1, (sid2)}
	READ (1, 0), 0, 1024 {fh1, (sid2)} -> {fh1, (sid2)}		READ (1, 0), 0, 1024 {fh1, (sid2)} -> {fh1, (sid2)}
	LOCKU 0, 1024, (1, 0) {fh1, (sid2)} -> {fh1, (sid3)}		LOCKU 0, 1024, (1, 0) {fh1, (sid2)} -> {fh1, (sid3)}
	SAVEFH {fh1, (sid3)} -> {fh1, (sid3)}		SAVEFH {fh1, (sid3)} -> {fh1, (sid3)}
	PUTFH fh2 {fh1, (sid3)} -> {fh2, (0, 0)}		PUTFH fh2 {fh1, (sid3)} -> {fh2, (0, 0)}
	WRITE (1, 0), 0, 1024 {fh2, (0, 0)} -> {fh2, (0, 0)}		WRITE (1, 0), 0, 1024 {fh2, (0, 0)} -> {fh2, (0, 0)}
	RESTOREFH {fh2, (0, 0)} -> {fh1, (sid3)}		RESTOREFH {fh2, (0, 0)} -> {fh1, (sid3)}
	READ (1, 0), 1024, 1024 {fh1, (sid3)} -> {fh1, (sid3)}		READ (1, 0), 1024, 1024 {fh1, (sid3)} -> {fh1, (sid3)}]]></sourcecode>
	</artwork>		</figure>
	</figure>		<t>
	<t>
	The final example shows a disallowed use of		The final example shows a disallowed use of
	the current stateid. The client is attempting		the current stateid. The client is attempting
	to implicitly pass an anonymous special stateid, (0,0), to		to implicitly pass an anonymous special stateid, (0,0), to
	the READ operation. The server MUST return NFS4ERR_BAD_STATEID		the READ operation. The server <bcp14>MUST</bcp14> return NFS4ERR_BAD_STAT EID
	in the reply to the READ operation.		in the reply to the READ operation.
	</t>		</t>
	<figure anchor='csid_example4'>		<figure anchor="csid_example4">
	<artwork>		<sourcecode type="nfsv4compound"><![CDATA[
	PUTFH fh1 - -> {fh1, (0, 0)}		PUTFH fh1 - -> {fh1, (0, 0)}
	READ (1, 0), 0, 1024 {fh1, (0, 0)} -> NFS4ERR_BAD_STATEID		READ (1, 0), 0, 1024 {fh1, (0, 0)} -> NFS4ERR_BAD_STATEID]]></sourcecod
	</artwork>		e>
	</figure>		</figure>
			</section>
	</section>		</section>
	</section>		</section>
	</section>		<section toc="exclude" anchor="OP_COMPOUND_ERRORS" numbered="true">
			<name>ERRORS</name>
	<section toc="exclude" anchor="OP_COMPOUND_ERRORS" title="ERRORS">		<t>
	<t>
	COMPOUND will of course return every error that each operation on		COMPOUND will of course return every error that each operation on
	the fore channel can return (see <xref target="op_error_returns"/>).		the fore channel can return (see <xref target="op_error_returns" format="de fault"/>).
	However, if COMPOUND returns zero operations, obviously the error		However, if COMPOUND returns zero operations, obviously the error
	returned by COMPOUND has nothing to do with an error returned by		returned by COMPOUND has nothing to do with an error returned by
	an operation. The list of errors COMPOUND will return if it processes		an operation. The list of errors COMPOUND will return if it processes
	zero operations include:		zero operations include:
	</t>		</t>
	<texttable anchor="compounderrs">		<table anchor="compounderrs" align="center">
	<preamble>COMPOUND Error Returns</preamble>		<name>COMPOUND Error Returns</name>
	<ttcol align='left'>Error</ttcol>		<thead>
	<ttcol align='left'>Notes</ttcol>		<tr>
			<th align="left">Error</th>
	<c>NFS4ERR_BADCHAR</c> <c>The tag argument has a character the replier		<th align="left">Notes</th>
	does not support. </c>		</tr>
			</thead>
	<c>NFS4ERR_BADXDR</c> <c> </c>		<tbody>
			<tr>
	<c>NFS4ERR_DELAY</c> <c> </c>		<td align="left">NFS4ERR_BADCHAR</td>
			<td align="left">The tag argument has a character the replier
	<c>NFS4ERR_INVAL</c> <c>The tag argument is not in UTF-8 encoding.</c>		does not support. </td>
			</tr>
	<c>NFS4ERR_MINOR_VERS_MISMATCH</c> <c> </c>		<tr>
			<td align="left">NFS4ERR_BADXDR</td>
	<c>NFS4ERR_SERVERFAULT</c> <c> </c>		<td align="left"> </td>
			</tr>
	<c>NFS4ERR_TOO_MANY_OPS</c> <c> </c>		<tr>
			<td align="left">NFS4ERR_DELAY</td>
	<c>NFS4ERR_REP_TOO_BIG</c> <c> </c>		<td align="left"> </td>
			</tr>
	<c>NFS4ERR_REP_TOO_BIG_TO_CACHE</c> <c> </c>		<tr>
			<td align="left">NFS4ERR_INVAL</td>
	<c>NFS4ERR_REQ_TOO_BIG</c> <c> </c>		<td align="left">The tag argument is not in UTF-8 encoding.</td>
			</tr>
	</texttable>		<tr>
			<td align="left">NFS4ERR_MINOR_VERS_MISMATCH</td>
	</section>		<td align="left"> </td>
			</tr>
	</section>		<tr>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<td align="left">NFS4ERR_SERVERFAULT</td>
	$ -->		<td align="left"> </td>
	<!-- Copyright (C) The IETF Trust (2007) -->		</tr>
	<!-- Copyright (C) The Internet Society (2006) -->		<tr>
			<td align="left">NFS4ERR_TOO_MANY_OPS</td>
			<td align="left"> </td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_REP_TOO_BIG</td>
			<td align="left"> </td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_REP_TOO_BIG_TO_CACHE</td>
			<td align="left"> </td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_REQ_TOO_BIG</td>
			<td align="left"> </td>
			</tr>
			</tbody>
			</table>
			</section>
			</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="operation_mandlist" numbered="true" toc="default">
	$ -->		<name>Operations: <bcp14>REQUIRED</bcp14>, <bcp14>RECOMMENDED</bcp14>, or
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<bcp14>OPTIONAL</bcp14></name>
	<section anchor="operation_mandlist"		<t>
	title="Operations: REQUIRED, RECOMMENDED, or OPTIONAL">
	<t>
	The following tables summarize the operations of the NFSv4.1		The following tables summarize the operations of the NFSv4.1
	protocol and the corresponding designation of REQUIRED,		protocol and the corresponding designation of <bcp14>REQUIRED</bcp14>,
	RECOMMENDED, and OPTIONAL to implement or MUST NOT implement. The		<bcp14>RECOMMENDED</bcp14>, and <bcp14>OPTIONAL</bcp14> to implement or <bcp
	designation of MUST NOT implement is reserved for those operations		14>MUST NOT</bcp14> implement. The
	that were defined in NFSv4.0 and MUST NOT be implemented in NFSv4.1.		designation of <bcp14>MUST NOT</bcp14> implement is reserved for those opera
	</t>		tions
	<t>		that were defined in NFSv4.0 and <bcp14>MUST NOT</bcp14> be implemented in N
	For the most part, the REQUIRED, RECOMMENDED, or OPTIONAL designation for		FSv4.1.
			</t>
			<t>
			For the most part, the <bcp14>REQUIRED</bcp14>, <bcp14>RECOMMENDED</bcp14>,
			or <bcp14>OPTIONAL</bcp14> designation for
	operations sent by the client is for		operations sent by the client is for
	the server implementation. The client is generally required to		the server implementation. The client is generally required to
	implement the operations needed for the operating environment for		implement the operations needed for the operating environment for
	which it serves. For example, a read-only NFSv4.1 client would		which it serves. For example, a read-only NFSv4.1 client would
	have no need to implement the WRITE operation and is not required		have no need to implement the WRITE operation and is not required
	to do so.		to do so.
	</t>		</t>
	<t>		<t>
	The REQUIRED or OPTIONAL designation for		The <bcp14>REQUIRED</bcp14> or <bcp14>OPTIONAL</bcp14> designation for
	callback operations sent by the server is for both the client		callback operations sent by the server is for both the client
	and server. Generally, the client has the option of		and server. Generally, the client has the option of
	creating the backchannel and sending the operations on the		creating the backchannel and sending the operations on the
	fore channel that will be a catalyst for the server sending		fore channel that will be a catalyst for the server sending
	callback operations. A partial		callback operations. A partial
	exception is CB_RECALL_SLOT; the only way the client can		exception is CB_RECALL_SLOT; the only way the client can
	avoid supporting this operation is by not creating a backchannel.		avoid supporting this operation is by not creating a backchannel.
	</t>		</t>
	<t>		<t>
	Since this is a summary of the operations and their designation,		Since this is a summary of the operations and their designation,
	there are subtleties that are not presented here. Therefore, if		there are subtleties that are not presented here. Therefore, if
	there is a question of the requirements of implementation, the		there is a question of the requirements of implementation, the
	operation descriptions themselves must be consulted along with		operation descriptions themselves must be consulted along with
	other relevant explanatory text within this specification.		other relevant explanatory text within this specification.
	</t>		</t>
	<t>		<t>
	The abbreviations used in the second and third columns of the table		The abbreviations used in the second and third columns of the table
	are defined as follows.		are defined as follows.
	<list style="hanging">
	<t hangText="REQ">
	REQUIRED to implement
	</t>		</t>
	<t hangText="REC">		<dl newline="false" spacing="normal">
			<dt>REQ</dt>
			<dd>
			<bcp14>REQUIRED</bcp14> to implement
			</dd>
			<dt>REC</dt>
			<dd>
	RECOMMEND to implement		RECOMMEND to implement
	</t>		</dd>
	<t hangText="OPT">		<dt>OPT</dt>
	OPTIONAL to implement		<dd>
	</t>		<bcp14>OPTIONAL</bcp14> to implement
	<t hangText="MNI">		</dd>
	MUST NOT implement		<dt>MNI</dt>
	</t>		<dd>
	</list>		<bcp14>MUST NOT</bcp14> implement
	</t>		</dd>
			</dl>
	<t> For the NFSv4.1 features that are OPTIONAL, the operations that		<t> For the NFSv4.1 features that are <bcp14>OPTIONAL</bcp14>, the operati
	support those features are OPTIONAL, and the server would return		ons that
			support those features are <bcp14>OPTIONAL</bcp14>, and the server would ret
			urn
	NFS4ERR_NOTSUPP in response to the client's use of those		NFS4ERR_NOTSUPP in response to the client's use of those
	operations. If an OPTIONAL feature is supported, it is possible		operations. If an <bcp14>OPTIONAL</bcp14> feature is supported, it is possi
	that a set of operations related to the feature become REQUIRED		ble
			that a set of operations related to the feature become <bcp14>REQUIRED</bcp1
			4>
	to implement. The third column of the table designates the		to implement. The third column of the table designates the
	feature(s) and if the operation is REQUIRED or OPTIONAL in the		feature(s) and if the operation is <bcp14>REQUIRED</bcp14> or <bcp14>OPTIONA L</bcp14> in the
	presence of support for the feature.		presence of support for the feature.
	</t>		</t>
	<t>		<t>
	The OPTIONAL features identified and their abbreviations are as		The <bcp14>OPTIONAL</bcp14> features identified and their abbreviations are
			as
	follows:		follows:
	<list style="hanging">
	<t hangText="pNFS">
	Parallel NFS
	</t>		</t>
	<t hangText="FDELG">		<dl newline="false" spacing="normal">
			<dt>pNFS</dt>
			<dd>
			Parallel NFS
			</dd>
			<dt>FDELG</dt>
			<dd>
	File Delegations		File Delegations
	</t>		</dd>
	<t hangText="DDELG">		<dt>DDELG</dt>
			<dd>
	Directory Delegations		Directory Delegations
	</t>		</dd>
	</list>		</dl>
	</t>		<table align="center">
	<texttable>		<name>Operations</name>
			<thead>
	<preamble> Operations </preamble>		<tr>
			<th align="left">Operation</th>
	<ttcol align='left' >Operation</ttcol>		<th align="left">REQ, REC, OPT, or MNI</th>
	<ttcol align='left' >REQ, REC, OPT, or MNI</ttcol>		<th align="left">Feature (REQ, REC, or OPT)</th>
	<ttcol align='left' >Feature (REQ, REC, or OPT)</ttcol>		<th align="left">Definition</th>
	<ttcol align='left' >Definition</ttcol>		</tr>
			</thead>
	<c> ACCESS </c>		<tbody>
	<c>REQ</c>		<tr>
	<c></c>		<td align="left"> ACCESS </td>
	<c> <xref target="OP_ACCESS" /> </c>		<td align="left">REQ</td>
			<td align="left"/>
	<c> BACKCHANNEL_CTL </c>		<td align="left">
	<c>REQ</c>		<xref target="OP_ACCESS" format="default"/> </td>
	<c></c>		</tr>
	<c> <xref target="OP_BACKCHANNEL_CTL" /> </c>		<tr>
			<td align="left"> BACKCHANNEL_CTL </td>
	<c> BIND_CONN_TO_SESSION</c>		<td align="left">REQ</td>
	<c>REQ</c>		<td align="left"/>
	<c></c>		<td align="left">
	<c> <xref target="OP_BIND_CONN_TO_SESSION" /> </c>		<xref target="OP_BACKCHANNEL_CTL" format="default"/> </td>
			</tr>
	<c> CLOSE </c>		<tr>
	<c>REQ</c>		<td align="left"> BIND_CONN_TO_SESSION</td>
	<c></c>		<td align="left">REQ</td>
	<c> <xref target="OP_CLOSE" /> </c>		<td align="left"/>
			<td align="left">
	<c> COMMIT </c>		<xref target="OP_BIND_CONN_TO_SESSION" format="default"/> </td>
	<c>REQ</c>		</tr>
	<c></c>		<tr>
	<c> <xref target="OP_COMMIT" /> </c>		<td align="left"> CLOSE </td>
			<td align="left">REQ</td>
	<c> CREATE </c>		<td align="left"/>
	<c>REQ</c>		<td align="left">
	<c></c>		<xref target="OP_CLOSE" format="default"/> </td>
	<c> <xref target="OP_CREATE" /> </c>		</tr>
			<tr>
	<c> CREATE_SESSION </c>		<td align="left"> COMMIT </td>
	<c>REQ</c>		<td align="left">REQ</td>
	<c></c>		<td align="left"/>
	<c> <xref target="OP_CREATE_SESSION" /> </c>		<td align="left">
			<xref target="OP_COMMIT" format="default"/> </td>
	<c> DELEGPURGE </c>		</tr>
	<c>OPT</c>		<tr>
	<c>FDELG (REQ)</c>		<td align="left"> CREATE </td>
	<c> <xref target="OP_DELEGPURGE" /> </c>		<td align="left">REQ</td>
			<td align="left"/>
	<c> DELEGRETURN </c>		<td align="left">
	<c>OPT</c>		<xref target="OP_CREATE" format="default"/> </td>
	<c>FDELG, DDELG, pNFS (REQ)</c>		</tr>
	<c> <xref target="OP_DELEGRETURN" /> </c>		<tr>
			<td align="left"> CREATE_SESSION </td>
	<c> DESTROY_CLIENTID </c>		<td align="left">REQ</td>
	<c>REQ</c>		<td align="left"/>
	<c></c>		<td align="left">
	<c> <xref target="OP_DESTROY_CLIENTID" /> </c>		<xref target="OP_CREATE_SESSION" format="default"/> </td>
			</tr>
	<c> DESTROY_SESSION </c>		<tr>
	<c>REQ</c>		<td align="left"> DELEGPURGE </td>
	<c></c>		<td align="left">OPT</td>
	<c> <xref target="OP_DESTROY_SESSION" /> </c>		<td align="left">FDELG (REQ)</td>
			<td align="left">
	<c> EXCHANGE_ID </c>		<xref target="OP_DELEGPURGE" format="default"/> </td>
	<c>REQ</c>		</tr>
	<c></c>		<tr>
	<c> <xref target="OP_EXCHANGE_ID" /> </c>		<td align="left"> DELEGRETURN </td>
			<td align="left">OPT</td>
	<c> FREE_STATEID </c>		<td align="left">FDELG, DDELG, pNFS (REQ)</td>
	<c>REQ</c>		<td align="left">
	<c></c>		<xref target="OP_DELEGRETURN" format="default"/> </td>
	<c> <xref target="OP_FREE_STATEID" /> </c>		</tr>
			<tr>
	<c> GETATTR </c>		<td align="left"> DESTROY_CLIENTID </td>
	<c>REQ</c>		<td align="left">REQ</td>
	<c></c>		<td align="left"/>
	<c> <xref target="OP_GETATTR" /> </c>		<td align="left">
			<xref target="OP_DESTROY_CLIENTID" format="default"/> </td>
	<c> GETDEVICEINFO </c>		</tr>
	<c>OPT</c>		<tr>
	<c>pNFS (REQ)</c>		<td align="left"> DESTROY_SESSION </td>
	<c> <xref target="OP_GETDEVICEINFO" /> </c>		<td align="left">REQ</td>
			<td align="left"/>
	<c> GETDEVICELIST</c>		<td align="left">
	<c>OPT</c>		<xref target="OP_DESTROY_SESSION" format="default"/> </td>
	<c>pNFS (OPT)</c>		</tr>
	<c> <xref target="OP_GETDEVICELIST" /> </c>		<tr>
			<td align="left"> EXCHANGE_ID </td>
	<c> GETFH </c>		<td align="left">REQ</td>
	<c>REQ</c>		<td align="left"/>
	<c></c>		<td align="left">
	<c> <xref target="OP_GETFH" /> </c>		<xref target="OP_EXCHANGE_ID" format="default"/> </td>
			</tr>
	<c> GET_DIR_DELEGATION </c>		<tr>
	<c>OPT</c>		<td align="left"> FREE_STATEID </td>
	<c>DDELG (REQ)</c>		<td align="left">REQ</td>
	<c> <xref target="OP_GET_DIR_DELEGATION" /> </c>		<td align="left"/>
			<td align="left">
	<c> LAYOUTCOMMIT </c>		<xref target="OP_FREE_STATEID" format="default"/> </td>
	<c>OPT</c>		</tr>
	<c>pNFS (REQ)</c>		<tr>
	<c> <xref target="OP_LAYOUTCOMMIT" /> </c>		<td align="left"> GETATTR </td>
			<td align="left">REQ</td>
	<c> LAYOUTGET </c>		<td align="left"/>
	<c>OPT</c>		<td align="left">
	<c>pNFS (REQ)</c>		<xref target="OP_GETATTR" format="default"/> </td>
	<c> <xref target="OP_LAYOUTGET" /> </c>		</tr>
			<tr>
	<c> LAYOUTRETURN </c>		<td align="left"> GETDEVICEINFO </td>
	<c>OPT</c>		<td align="left">OPT</td>
	<c>pNFS (REQ)</c>		<td align="left">pNFS (REQ)</td>
	<c> <xref target="OP_LAYOUTRETURN" /> </c>		<td align="left">
			<xref target="OP_GETDEVICEINFO" format="default"/> </td>
	<c> LINK </c>		</tr>
	<c>OPT</c>		<tr>
	<c></c>		<td align="left"> GETDEVICELIST</td>
	<c> <xref target="OP_LINK" /> </c>		<td align="left">OPT</td>
			<td align="left">pNFS (OPT)</td>
	<c> LOCK </c>		<td align="left">
	<c>REQ</c>		<xref target="OP_GETDEVICELIST" format="default"/> </td>
	<c></c>		</tr>
	<c> <xref target="OP_LOCK" /> </c>		<tr>
			<td align="left"> GETFH </td>
	<c> LOCKT </c>		<td align="left">REQ</td>
	<c>REQ</c>		<td align="left"/>
	<c></c>		<td align="left">
	<c> <xref target="OP_LOCKT" /> </c>		<xref target="OP_GETFH" format="default"/> </td>
			</tr>
	<c> LOCKU </c>		<tr>
	<c>REQ</c>		<td align="left"> GET_DIR_DELEGATION </td>
	<c></c>		<td align="left">OPT</td>
	<c> <xref target="OP_LOCKU" /> </c>		<td align="left">DDELG (REQ)</td>
			<td align="left">
	<c> LOOKUP </c>		<xref target="OP_GET_DIR_DELEGATION" format="default"/> </td>
	<c>REQ</c>		</tr>
	<c></c>		<tr>
	<c> <xref target="OP_LOOKUP" /> </c>		<td align="left"> LAYOUTCOMMIT </td>
			<td align="left">OPT</td>
	<c> LOOKUPP </c>		<td align="left">pNFS (REQ)</td>
	<c>REQ</c>		<td align="left">
	<c></c>		<xref target="OP_LAYOUTCOMMIT" format="default"/> </td>
	<c> <xref target="OP_LOOKUPP" /> </c>		</tr>
			<tr>
	<c> NVERIFY </c>		<td align="left"> LAYOUTGET </td>
	<c>REQ</c>		<td align="left">OPT</td>
	<c></c>		<td align="left">pNFS (REQ)</td>
	<c> <xref target="OP_NVERIFY" /> </c>		<td align="left">
			<xref target="OP_LAYOUTGET" format="default"/> </td>
	<c> OPEN </c>		</tr>
	<c>REQ</c>		<tr>
	<c></c>		<td align="left"> LAYOUTRETURN </td>
	<c> <xref target="OP_OPEN" /> </c>		<td align="left">OPT</td>
			<td align="left">pNFS (REQ)</td>
	<c> OPENATTR </c>		<td align="left">
	<c>OPT</c>		<xref target="OP_LAYOUTRETURN" format="default"/> </td>
	<c></c>		</tr>
	<c> <xref target="OP_OPENATTR" /> </c>		<tr>
			<td align="left"> LINK </td>
	<c> OPEN_CONFIRM </c>		<td align="left">OPT</td>
	<c>MNI</c>		<td align="left"/>
	<c></c>		<td align="left">
	<c> N/A </c>		<xref target="OP_LINK" format="default"/> </td>
			</tr>
	<c> OPEN_DOWNGRADE </c>		<tr>
	<c>REQ</c>		<td align="left"> LOCK </td>
	<c></c>		<td align="left">REQ</td>
	<c> <xref target="OP_OPEN_DOWNGRADE" /> </c>		<td align="left"/>
			<td align="left">
	<c> PUTFH </c>		<xref target="OP_LOCK" format="default"/> </td>
	<c>REQ</c>		</tr>
	<c></c>		<tr>
	<c> <xref target="OP_PUTFH" /> </c>		<td align="left"> LOCKT </td>
			<td align="left">REQ</td>
	<c> PUTPUBFH </c>		<td align="left"/>
	<c>REQ</c>		<td align="left">
	<c></c>		<xref target="OP_LOCKT" format="default"/> </td>
	<c> <xref target="OP_PUTPUBFH" /> </c>		</tr>
			<tr>
	<c> PUTROOTFH </c>		<td align="left"> LOCKU </td>
	<c>REQ</c>		<td align="left">REQ</td>
	<c></c>		<td align="left"/>
	<c> <xref target="OP_PUTROOTFH" /> </c>		<td align="left">
			<xref target="OP_LOCKU" format="default"/> </td>
	<c> READ </c>		</tr>
	<c>REQ</c>		<tr>
	<c></c>		<td align="left"> LOOKUP </td>
	<c> <xref target="OP_READ" /> </c>		<td align="left">REQ</td>
			<td align="left"/>
	<c> READDIR </c>		<td align="left">
	<c>REQ</c>		<xref target="OP_LOOKUP" format="default"/> </td>
	<c></c>		</tr>
	<c> <xref target="OP_READDIR" /> </c>		<tr>
			<td align="left"> LOOKUPP </td>
	<c> READLINK </c>		<td align="left">REQ</td>
	<c>OPT</c>		<td align="left"/>
	<c></c>		<td align="left">
	<c> <xref target="OP_READLINK" /> </c>		<xref target="OP_LOOKUPP" format="default"/> </td>
			</tr>
	<c> RECLAIM_COMPLETE </c>		<tr>
	<c>REQ</c>		<td align="left"> NVERIFY </td>
	<c></c>		<td align="left">REQ</td>
	<c> <xref target="OP_RECLAIM_COMPLETE" /> </c>		<td align="left"/>
			<td align="left">
	<c> RELEASE_LOCKOWNER</c>		<xref target="OP_NVERIFY" format="default"/> </td>
	<c>MNI</c>		</tr>
	<c></c>		<tr>
	<c> N/A </c>		<td align="left"> OPEN </td>
			<td align="left">REQ</td>
	<c> REMOVE </c>		<td align="left"/>
	<c>REQ</c>		<td align="left">
	<c></c>		<xref target="OP_OPEN" format="default"/> </td>
	<c> <xref target="OP_REMOVE" /> </c>		</tr>
			<tr>
	<c> RENAME </c>		<td align="left"> OPENATTR </td>
	<c>REQ</c>		<td align="left">OPT</td>
	<c></c>		<td align="left"/>
	<c> <xref target="OP_RENAME" /> </c>		<td align="left">
			<xref target="OP_OPENATTR" format="default"/> </td>
	<c> RENEW </c>		</tr>
	<c>MNI</c>		<tr>
	<c></c>		<td align="left"> OPEN_CONFIRM </td>
	<c> N/A </c>		<td align="left">MNI</td>
			<td align="left"/>
	<c> RESTOREFH </c>		<td align="left"> N/A </td>
	<c>REQ</c>		</tr>
	<c></c>		<tr>
	<c> <xref target="OP_RESTOREFH" /> </c>		<td align="left"> OPEN_DOWNGRADE </td>
			<td align="left">REQ</td>
	<c> SAVEFH </c>		<td align="left"/>
	<c>REQ</c>		<td align="left">
	<c></c>		<xref target="OP_OPEN_DOWNGRADE" format="default"/> </td>
	<c> <xref target="OP_SAVEFH" /> </c>		</tr>
			<tr>
	<c> SECINFO </c>		<td align="left"> PUTFH </td>
	<c>REQ</c>		<td align="left">REQ</td>
	<c></c>		<td align="left"/>
	<c> <xref target="OP_SECINFO" /> </c>		<td align="left">
			<xref target="OP_PUTFH" format="default"/> </td>
	<c> SECINFO_NO_NAME </c>		</tr>
	<c>REC</c>		<tr>
	<c>pNFS file layout (REQ)</c>		<td align="left"> PUTPUBFH </td>
	<c> <xref target="OP_SECINFO_NO_NAME" />,		<td align="left">REQ</td>
	<xref target="file_security_considerations"/>		<td align="left"/>
	</c>		<td align="left">
			<xref target="OP_PUTPUBFH" format="default"/> </td>
	<c> SEQUENCE </c>		</tr>
	<c>REQ</c>		<tr>
	<c></c>		<td align="left"> PUTROOTFH </td>
	<c> <xref target="OP_SEQUENCE" /> </c>		<td align="left">REQ</td>
			<td align="left"/>
	<c> SETATTR </c>		<td align="left">
	<c>REQ</c>		<xref target="OP_PUTROOTFH" format="default"/> </td>
	<c></c>		</tr>
	<c> <xref target="OP_SETATTR" /> </c>		<tr>
			<td align="left"> READ </td>
	<c> SETCLIENTID</c>		<td align="left">REQ</td>
	<c>MNI</c>		<td align="left"/>
	<c></c>		<td align="left">
	<c> N/A </c>		<xref target="OP_READ" format="default"/> </td>
			</tr>
	<c> SETCLIENTID_CONFIRM</c>		<tr>
	<c>MNI</c>		<td align="left"> READDIR </td>
	<c></c>		<td align="left">REQ</td>
	<c> N/A </c>		<td align="left"/>
			<td align="left">
	<c> SET_SSV</c>		<xref target="OP_READDIR" format="default"/> </td>
	<c>REQ</c>		</tr>
	<c></c>		<tr>
	<c> <xref target="OP_SET_SSV" /> </c>		<td align="left"> READLINK </td>
			<td align="left">OPT</td>
	<c> TEST_STATEID </c>		<td align="left"/>
	<c>REQ</c>		<td align="left">
	<c></c>		<xref target="OP_READLINK" format="default"/> </td>
	<c> <xref target="OP_TEST_STATEID" /> </c>		</tr>
			<tr>
	<c> VERIFY </c>		<td align="left"> RECLAIM_COMPLETE </td>
	<c>REQ</c>		<td align="left">REQ</td>
	<c></c>		<td align="left"/>
	<c> <xref target="OP_VERIFY" /> </c>		<td align="left">
			<xref target="OP_RECLAIM_COMPLETE" format="default"/> </td>
	<c> WANT_DELEGATION</c>		</tr>
	<c>OPT</c>		<tr>
	<c>FDELG (OPT)</c>		<td align="left"> RELEASE_LOCKOWNER</td>
	<c> <xref target="OP_WANT_DELEGATION" /> </c>		<td align="left">MNI</td>
			<td align="left"/>
	<c> WRITE </c>		<td align="left"> N/A </td>
	<c>REQ</c>		</tr>
	<c></c>		<tr>
	<c> <xref target="OP_WRITE" /> </c>		<td align="left"> REMOVE </td>
			<td align="left">REQ</td>
	</texttable>		<td align="left"/>
			<td align="left">
	<texttable>		<xref target="OP_REMOVE" format="default"/> </td>
			</tr>
	<preamble> Callback Operations </preamble>		<tr>
	<ttcol align='left' >Operation</ttcol>		<td align="left"> RENAME </td>
	<ttcol align='left' >REQ, REC, OPT, or MNI</ttcol>		<td align="left">REQ</td>
	<ttcol align='left' >Feature (REQ, REC, or OPT)</ttcol>		<td align="left"/>
	<ttcol align='left' >Definition</ttcol>		<td align="left">
			<xref target="OP_RENAME" format="default"/> </td>
	<c> CB_GETATTR </c>		</tr>
	<c>OPT</c>		<tr>
	<c>FDELG (REQ)</c>		<td align="left"> RENEW </td>
	<c> <xref target="OP_CB_GETATTR" /> </c>		<td align="left">MNI</td>
			<td align="left"/>
	<c> CB_LAYOUTRECALL </c>		<td align="left"> N/A </td>
	<c>OPT</c>		</tr>
	<c>pNFS (REQ)</c>		<tr>
	<c> <xref target="OP_CB_LAYOUTRECALL" /> </c>		<td align="left"> RESTOREFH </td>
			<td align="left">REQ</td>
	<c> CB_NOTIFY </c>		<td align="left"/>
	<c>OPT</c>		<td align="left">
	<c>DDELG (REQ)</c>		<xref target="OP_RESTOREFH" format="default"/> </td>
	<c> <xref target="OP_CB_NOTIFY" /> </c>		</tr>
			<tr>
	<c> CB_NOTIFY_DEVICEID </c>		<td align="left"> SAVEFH </td>
	<c>OPT</c>		<td align="left">REQ</td>
	<c>pNFS (OPT)</c>		<td align="left"/>
	<c> <xref target="OP_CB_NOTIFY_DEVICEID" /> </c>		<td align="left">
			<xref target="OP_SAVEFH" format="default"/> </td>
	<c> CB_NOTIFY_LOCK </c>		</tr>
	<c>OPT</c>		<tr>
	<c></c>		<td align="left"> SECINFO </td>
	<c> <xref target="OP_CB_NOTIFY_LOCK" /> </c>		<td align="left">REQ</td>
			<td align="left"/>
	<c> CB_PUSH_DELEG </c>		<td align="left">
	<c>OPT</c>		<xref target="OP_SECINFO" format="default"/> </td>
	<c>FDELG (OPT)</c>		</tr>
	<c> <xref target="OP_CB_PUSH_DELEG" /> </c>		<tr>
			<td align="left"> SECINFO_NO_NAME </td>
	<c> CB_RECALL </c>		<td align="left">REC</td>
	<c>OPT</c>		<td align="left">pNFS file layout (REQ)</td>
	<c>FDELG, DDELG, pNFS (REQ)</c>		<td align="left">
	<c> <xref target="OP_CB_RECALL" /> </c>		<xref target="OP_SECINFO_NO_NAME" format="default"/>,
			<xref target="file_security_considerations" format="default"/>
	<c> CB_RECALL_ANY </c>		</td>
	<c>OPT</c>		</tr>
	<c>FDELG, DDELG, pNFS (REQ)</c>		<tr>
	<c> <xref target="OP_CB_RECALL_ANY" /> </c>		<td align="left"> SEQUENCE </td>
			<td align="left">REQ</td>
	<c> CB_RECALL_SLOT </c>		<td align="left"/>
	<c>REQ</c>		<td align="left">
	<c></c>		<xref target="OP_SEQUENCE" format="default"/> </td>
	<c> <xref target="OP_CB_RECALL_SLOT" /> </c>		</tr>
			<tr>
	<c> CB_RECALLABLE_OBJ_AVAIL </c>		<td align="left"> SETATTR </td>
	<c>OPT</c>		<td align="left">REQ</td>
	<c>DDELG, pNFS (REQ)</c>		<td align="left"/>
	<c> <xref target="OP_CB_RECALLABLE_OBJ_AVAIL" /> </c>		<td align="left">
			<xref target="OP_SETATTR" format="default"/> </td>
	<c> CB_SEQUENCE </c>		</tr>
	<c>OPT</c>		<tr>
	<c>FDELG, DDELG, pNFS (REQ)</c>		<td align="left"> SETCLIENTID</td>
	<c> <xref target="OP_CB_SEQUENCE" /> </c>		<td align="left">MNI</td>
			<td align="left"/>
	<c> CB_WANTS_CANCELLED </c>		<td align="left"> N/A </td>
	<c>OPT</c>		</tr>
	<c>FDELG, DDELG, pNFS (REQ)</c>		<tr>
	<c> <xref target="OP_CB_WANTS_CANCELLED" /> </c>		<td align="left"> SETCLIENTID_CONFIRM</td>
			<td align="left">MNI</td>
	</texttable>		<td align="left"/>
	</section>		<td align="left"> N/A </td>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		</tr>
	$ -->		<tr>
	<!-- Copyright (C) The IETF Trust (2007) -->		<td align="left"> SET_SSV</td>
	<!-- Copyright (C) The Internet Society (2006) -->		<td align="left">REQ</td>
	<section anchor="nfsv41operations" title="NFSv4.1 Operations">		<td align="left"/>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<td align="left">
	$ -->		<xref target="OP_SET_SSV" format="default"/> </td>
	<!-- Copyright (C) The IETF Trust (2007) -->		</tr>
	<!-- Copyright (C) The Internet Society (2006) -->		<tr>
	<section anchor="OP_ACCESS" title="Operation 3: ACCESS - Check Access Rights" >		<td align="left"> TEST_STATEID </td>
			<td align="left">REQ</td>
	<section toc="exclude" anchor="OP_ACCESS_ARGUMENTS" title="ARGUMENTS">		<td align="left"/>
	<figure>		<td align="left">
	<artwork>		<xref target="OP_TEST_STATEID" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> VERIFY </td>
			<td align="left">REQ</td>
			<td align="left"/>
			<td align="left">
			<xref target="OP_VERIFY" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> WANT_DELEGATION</td>
			<td align="left">OPT</td>
			<td align="left">FDELG (OPT)</td>
			<td align="left">
			<xref target="OP_WANT_DELEGATION" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> WRITE </td>
			<td align="left">REQ</td>
			<td align="left"/>
			<td align="left">
			<xref target="OP_WRITE" format="default"/> </td>
			</tr>
			</tbody>
			</table>
			<table align="center">
			<name>Callback Operations</name>
			<thead>
			<tr>
			<th align="left">Operation</th>
			<th align="left">REQ, REC, OPT, or MNI</th>
			<th align="left">Feature (REQ, REC, or OPT)</th>
			<th align="left">Definition</th>
			</tr>
			</thead>
			<tbody>
			<tr>
			<td align="left"> CB_GETATTR </td>
			<td align="left">OPT</td>
			<td align="left">FDELG (REQ)</td>
			<td align="left">
			<xref target="OP_CB_GETATTR" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> CB_LAYOUTRECALL </td>
			<td align="left">OPT</td>
			<td align="left">pNFS (REQ)</td>
			<td align="left">
			<xref target="OP_CB_LAYOUTRECALL" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> CB_NOTIFY </td>
			<td align="left">OPT</td>
			<td align="left">DDELG (REQ)</td>
			<td align="left">
			<xref target="OP_CB_NOTIFY" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> CB_NOTIFY_DEVICEID </td>
			<td align="left">OPT</td>
			<td align="left">pNFS (OPT)</td>
			<td align="left">
			<xref target="OP_CB_NOTIFY_DEVICEID" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> CB_NOTIFY_LOCK </td>
			<td align="left">OPT</td>
			<td align="left"/>
			<td align="left">
			<xref target="OP_CB_NOTIFY_LOCK" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> CB_PUSH_DELEG </td>
			<td align="left">OPT</td>
			<td align="left">FDELG (OPT)</td>
			<td align="left">
			<xref target="OP_CB_PUSH_DELEG" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> CB_RECALL </td>
			<td align="left">OPT</td>
			<td align="left">FDELG, DDELG, pNFS (REQ)</td>
			<td align="left">
			<xref target="OP_CB_RECALL" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> CB_RECALL_ANY </td>
			<td align="left">OPT</td>
			<td align="left">FDELG, DDELG, pNFS (REQ)</td>
			<td align="left">
			<xref target="OP_CB_RECALL_ANY" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> CB_RECALL_SLOT </td>
			<td align="left">REQ</td>
			<td align="left"/>
			<td align="left">
			<xref target="OP_CB_RECALL_SLOT" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> CB_RECALLABLE_OBJ_AVAIL </td>
			<td align="left">OPT</td>
			<td align="left">DDELG, pNFS (REQ)</td>
			<td align="left">
			<xref target="OP_CB_RECALLABLE_OBJ_AVAIL" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> CB_SEQUENCE </td>
			<td align="left">OPT</td>
			<td align="left">FDELG, DDELG, pNFS (REQ)</td>
			<td align="left">
			<xref target="OP_CB_SEQUENCE" format="default"/> </td>
			</tr>
			<tr>
			<td align="left"> CB_WANTS_CANCELLED </td>
			<td align="left">OPT</td>
			<td align="left">FDELG, DDELG, pNFS (REQ)</td>
			<td align="left">
			<xref target="OP_CB_WANTS_CANCELLED" format="default"/> </td>
			</tr>
			</tbody>
			</table>
			</section>
			<section anchor="nfsv41operations" numbered="true" toc="default">
			<name>NFSv4.1 Operations</name>
			<section anchor="OP_ACCESS" numbered="true" toc="default">
			<name>Operation 3: ACCESS - Check Access Rights</name>
			<section toc="exclude" anchor="OP_ACCESS_ARGUMENTS" numbered="true">
			<name>ARGUMENTS</name>
			<sourcecode type="xdr"><![CDATA[
	const ACCESS4_READ = 0x00000001;		const ACCESS4_READ = 0x00000001;
	const ACCESS4_LOOKUP = 0x00000002;		const ACCESS4_LOOKUP = 0x00000002;
	const ACCESS4_MODIFY = 0x00000004;		const ACCESS4_MODIFY = 0x00000004;
	const ACCESS4_EXTEND = 0x00000008;		const ACCESS4_EXTEND = 0x00000008;
	const ACCESS4_DELETE = 0x00000010;		const ACCESS4_DELETE = 0x00000010;
	const ACCESS4_EXECUTE = 0x00000020;		const ACCESS4_EXECUTE = 0x00000020;
	struct ACCESS4args {		struct ACCESS4args {
	/* CURRENT_FH: object */		/* CURRENT_FH: object */
	uint32_t access;		uint32_t access;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_ACCESS_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_ACCESS_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct ACCESS4resok {		struct ACCESS4resok {
	uint32_t supported;		uint32_t supported;
	uint32_t access;		uint32_t access;
	};		};
	union ACCESS4res switch (nfsstat4 status) {		union ACCESS4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	ACCESS4resok resok4;		ACCESS4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_ACCESS_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_ACCESS_DESCRIPTION" title="DESCRIPTION">
	<t>
	ACCESS determines the access rights that a user, as identified by the		ACCESS determines the access rights that a user, as identified by the
	credentials in the RPC request, has with respect to the file system		credentials in the RPC request, has with respect to the file system
	object specified by the current filehandle. The client encodes the		object specified by the current filehandle. The client encodes the
	set of access rights that are to be checked in the bit mask "access".		set of access rights that are to be checked in the bit mask "access".
	The server checks the permissions encoded in the bit mask. If a		The server checks the permissions encoded in the bit mask. If a
	status of NFS4_OK is returned, two bit masks are included in the		status of NFS4_OK is returned, two bit masks are included in the
	response. The first, "supported", represents the access rights for		response. The first, "supported", represents the access rights for
	which the server can verify reliably. The second, "access",		which the server can verify reliably. The second, "access",
	represents the access rights available to the user for the filehandle		represents the access rights available to the user for the filehandle
	provided. On success, the current filehandle retains its value.		provided. On success, the current filehandle retains its value.
	</t>		</t>
	<t>		<t>
	Note that the reply's supported and access fields MUST NOT		Note that the reply's supported and access fields <bcp14>MUST NOT</bcp14>
	contain more values than originally set in the request's		contain more values than originally set in the request's
	access field. For example, if the client sends an ACCESS		access field. For example, if the client sends an ACCESS
	operation with just the ACCESS4_READ value set and the		operation with just the ACCESS4_READ value set and the
	server supports this value, the server MUST NOT set more		server supports this value, the server <bcp14>MUST NOT</bcp14> set more
	than ACCESS4_READ in the supported field even if it could		than ACCESS4_READ in the supported field even if it could
	have reliably checked other values.		have reliably checked other values.
	</t>		</t>
	<t>		<t>
	The reply's access field MUST NOT contain more values than the		The reply's access field <bcp14>MUST NOT</bcp14> contain more values than t
			he
	supported field.		supported field.
	</t>		</t>
	<t>		<t>
	The results of this operation are necessarily advisory in nature. A		The results of this operation are necessarily advisory in nature. A
	return status of NFS4_OK and the appropriate bit set in the bit mask		return status of NFS4_OK and the appropriate bit set in the bit mask
	do not imply that such access will be allowed to the file system		do not imply that such access will be allowed to the file system
	object in the future. This is because access rights can be revoked by		object in the future. This is because access rights can be revoked by
	the server at any time.		the server at any time.
	</t>		</t>
	<t>		<t>
	The following access permissions may be requested:		The following access permissions may be requested:
	<list style="hanging">
	<t hangText="ACCESS4_READ">
	Read data from file or read a directory.
	</t>		</t>
	<t hangText="ACCESS4_LOOKUP">		<dl newline="false" spacing="normal">
			<dt>ACCESS4_READ</dt>
			<dd>
			Read data from file or read a directory.
			</dd>
			<dt>ACCESS4_LOOKUP</dt>
			<dd>
	Look up a name in a directory (no meaning for non-directory objects).		Look up a name in a directory (no meaning for non-directory objects).
	</t>		</dd>
	<t hangText="ACCESS4_MODIFY">		<dt>ACCESS4_MODIFY</dt>
			<dd>
	Rewrite existing file data or modify existing directory entries.		Rewrite existing file data or modify existing directory entries.
	</t>		</dd>
	<t hangText="ACCESS4_EXTEND">		<dt>ACCESS4_EXTEND</dt>
			<dd>
	Write new data or add directory entries.		Write new data or add directory entries.
	</t>		</dd>
	<t hangText="ACCESS4_DELETE">		<dt>ACCESS4_DELETE</dt>
			<dd>
	Delete an existing directory entry.		Delete an existing directory entry.
	</t>		</dd>
	<t hangText="ACCESS4_EXECUTE">		<dt>ACCESS4_EXECUTE</dt>
			<dd>
	Execute a regular file (no meaning for a directory).		Execute a regular file (no meaning for a directory).
	</t>		</dd>
	</list>		</dl>
			<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	<t>		<t>
	ACCESS4_EXECUTE is a challenging semantic to implement because		ACCESS4_EXECUTE is a challenging semantic to implement because
	NFS provides remote file access, not remote		NFS provides remote file access, not remote
	execution. This leads to the following:		execution. This leads to the following:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Whether or not a regular file is executable ought to be		Whether or not a regular file is executable ought to be
	the responsibility of the NFS client and not the server. And yet		the responsibility of the NFS client and not the server. And yet
	the ACCESS operation is specified to seemingly require a server to		the ACCESS operation is specified to seemingly require a server to
	own that responsibility.		own that responsibility.
	</t>		</li>
	<t>		<li>
	When a client executes a regular file, it has to		When a client executes a regular file, it has to
	read the file from the server. Strictly speaking,		read the file from the server. Strictly speaking,
	the server should not allow the client to read a file		the server should not allow the client to read a file
	being executed unless the user has read permissions		being executed unless the user has read permissions
	on the file. Requiring		on the file. Requiring
	explicit read permissions on executable files in order to		explicit read permissions on executable files in order to
	access them over NFS is not going to be acceptable to		access them over NFS is not going to be acceptable to
	some users and storage administrators. Historically, NFS servers have allow ed		some users and storage administrators. Historically, NFS servers have allow ed
	a user to READ a file if the user has execute access		a user to READ a file if the user has execute access
	to the file.		to the file.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		As a practical example, the UNIX specification <xref target="access_api" form
	As a practical example, the UNIX specification <xref		at="default"/> states that an implementation
	target="access_api"/> states that an implementation
	claiming conformance to UNIX may indicate in the		claiming conformance to UNIX may indicate in the
	access() programming interface's result that a		access() programming interface's result that a
	privileged user has execute rights, even if no		privileged user has execute rights, even if no
	execute permission bits are set on the regular file's		execute permission bits are set on the regular file's
	attributes. It is possible to claim conformance		attributes. It is possible to claim conformance
	to the UNIX specification and instead not indicate		to the UNIX specification and instead not indicate
	execute rights in that situation, which is true for		execute rights in that situation, which is true for
	some operating environments. Suppose the operating		some operating environments. Suppose the operating
	environments of the client and server are implementing		environments of the client and server are implementing
	the access() semantics for privileged users differently,		the access() semantics for privileged users differently,
	and the ACCESS operation implementations of the client		and the ACCESS operation implementations of the client
	and server follow their respective access() semantics.		and server follow their respective access() semantics.
	This can cause undesired behavior:		This can cause undesired behavior:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	Suppose the client's access() interface returns X_OK		Suppose the client's access() interface returns X_OK
	if the user is privileged and no execute permission		if the user is privileged and no execute permission
	bits are set on the regular file's attribute, and the		bits are set on the regular file's attribute, and the
	server's access() interface does not return X_OK in		server's access() interface does not return X_OK in
	that situation. Then the client will be unable to		that situation. Then the client will be unable to
	execute files stored on the NFS server that could be		execute files stored on the NFS server that could be
	executed if stored on a non-NFS file system.		executed if stored on a non-NFS file system.
	</t>		</li>
	<t>		<li>
			<t>
	Suppose the client's access() interface does		Suppose the client's access() interface does
	not return X_OK if the user is privileged, and no		not return X_OK if the user is privileged, and no
	execute permission bits are set on the regular file's		execute permission bits are set on the regular file's
	attribute, and the server's access() interface does		attribute, and the server's access() interface does
	return X_OK in that situation. Then:		return X_OK in that situation. Then:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	The client will be able to execute files stored on		The client will be able to execute files stored on
	the NFS server that could be executed if stored on		the NFS server that could be executed if stored on
	a non-NFS file system, unless the client's execution		a non-NFS file system, unless the client's execution
	subsystem also checks for execute permission bits.		subsystem also checks for execute permission bits.
	</t>		</li>
	<t>		<li>
	Even if the execution subsystem is checking for		Even if the execution subsystem is checking for
	execute permission bits, there are more potential		execute permission bits, there are more potential
	issues. For example, suppose the client is invoking access()		issues. For example, suppose the client is invoking access()
	to build a "path search table" of all executable		to build a "path search table" of all executable
	files in the user's "search path", where the path		files in the user's "search path", where the path
	is a list of directories each containing executable		is a list of directories each containing executable
	files. Suppose there are two files each in separate		files. Suppose there are two files each in separate
	directories of the search path, such that files have		directories of the search path, such that files have
	the same component name. In the first directory		the same component name. In the first directory
	the file has no execute permission bits set,		the file has no execute permission bits set,
	and in the second directory the file has execute		and in the second directory the file has execute
	bits set. The path search table will indicate that		bits set. The path search table will indicate that
	the first directory has the executable file, but		the first directory has the executable file, but
	the execute subsystem will fail to execute it. The		the execute subsystem will fail to execute it. The
	command shell might fail to try the second file in		command shell might fail to try the second file in
	the second directory. And even if it did, this is		the second directory. And even if it did, this is
	a potential performance issue. Clearly, the desired		a potential performance issue. Clearly, the desired
	outcome for the client is for the path search table		outcome for the client is for the path search table
	to not contain the first file.		to not contain the first file.
	</t>		</li>
	</list>		</ul>
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	To deal with the problems described above, the "smart client,		To deal with the problems described above, the "smart client,
	stupid server" principle is used. The client owns overall		stupid server" principle is used. The client owns overall
	responsibility for determining execute access and		responsibility for determining execute access and
	relies on the server to parse the execution permissions		relies on the server to parse the execution permissions
	within the file's mode, acl, and dacl attributes. The		within the file's mode, acl, and dacl attributes. The
	rules for the client and server follow:		rules for the client and server follow:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	If the client is sending ACCESS in order to determine		If the client is sending ACCESS in order to determine
	if the user can read the file, the client SHOULD		if the user can read the file, the client <bcp14>SHOULD</bcp14>
	set ACCESS4_READ in the request's access field.		set ACCESS4_READ in the request's access field.
	</t>		</li>
	<t>		<li>
	If the client's operating environment only grants		If the client's operating environment only grants
	execution to the user if the user has execute access		execution to the user if the user has execute access
	according to the execute permissions in the mode,		according to the execute permissions in the mode,
	acl, and dacl attributes, then if the client wants		acl, and dacl attributes, then if the client wants
	to determine execute access, the client SHOULD send		to determine execute access, the client <bcp14>SHOULD</bcp14> send
	an ACCESS request with ACCESS4_EXECUTE bit set in the		an ACCESS request with ACCESS4_EXECUTE bit set in the
	request's access field.		request's access field.
	</t>		</li>
	<t>		<li>
	If the client's operating environment grants execution		If the client's operating environment grants execution
	to the user even if the user does not have execute		to the user even if the user does not have execute
	access according to the execute permissions in the		access according to the execute permissions in the
	mode, acl, and dacl attributes, then if the client		mode, acl, and dacl attributes, then if the client
	wants to determine execute access, it SHOULD send		wants to determine execute access, it <bcp14>SHOULD</bcp14> send
	an ACCESS request with both the ACCESS4_EXECUTE and		an ACCESS request with both the ACCESS4_EXECUTE and
	ACCESS4_READ bits set in the request's access field. This		ACCESS4_READ bits set in the request's access field. This
	way, if any read or execute permission grants the user		way, if any read or execute permission grants the user
	read or execute access (or if the server interprets		read or execute access (or if the server interprets
	the user as privileged), as indicated by the presence		the user as privileged), as indicated by the presence
	of ACCESS4_EXECUTE and/or ACCESS4_READ in the reply's		of ACCESS4_EXECUTE and/or ACCESS4_READ in the reply's
	access field, the client will be able to grant the		access field, the client will be able to grant the
	user execute access to the file.		user execute access to the file.
	</t>		</li>
			<li>
	<t>
	If the server supports execute permission bits, or some other		If the server supports execute permission bits, or some other
	method for denoting executability (e.g., the suffix of the name		method for denoting executability (e.g., the suffix of the name
	of the file might indicate execute), it MUST check		of the file might indicate execute), it <bcp14>MUST</bcp14> check
	only execute permissions, not read permissions, when determining		only execute permissions, not read permissions, when determining
	whether or not the reply will have ACCESS4_EXECUTE set in the access		whether or not the reply will have ACCESS4_EXECUTE set in the access
	field.		field.
	The server MUST NOT also examine read permission bits when		The server <bcp14>MUST NOT</bcp14> also examine read permission bits when
	determining whether or not the reply will have ACCESS4_EXECUTE		determining whether or not the reply will have ACCESS4_EXECUTE
	set in the access field. Even if the server's		set in the access field. Even if the server's
	operating environment would grant execute access to the		operating environment would grant execute access to the
	user (e.g., the user is privileged), the server MUST		user (e.g., the user is privileged), the server <bcp14>MUST
	NOT reply with ACCESS4_EXECUTE set in reply's access		NOT</bcp14> reply with ACCESS4_EXECUTE set in reply's access
	field unless there is at least one execute permission		field unless there is at least one execute permission
	bit set in the mode, acl, or dacl attributes. In the		bit set in the mode, acl, or dacl attributes. In the
	case of acl and dacl, the "one execute permission bit"		case of acl and dacl, the "one execute permission bit"
	MUST be an ACE4_EXECUTE bit set in an ALLOW ACE.		<bcp14>MUST</bcp14> be an ACE4_EXECUTE bit set in an ALLOW ACE.
	</t>		</li>
	<t>		<li>
	If the server does not support execute permission		If the server does not support execute permission
	bits or some other method for denoting executability, it MUST NOT set ACCESS 4_EXECUTE in the		bits or some other method for denoting executability, it <bcp14>MUST NOT</bc p14> set ACCESS4_EXECUTE in the
	reply's supported and access fields. If the client		reply's supported and access fields. If the client
	set ACCESS4_EXECUTE in the ACCESS request's access		set ACCESS4_EXECUTE in the ACCESS request's access
	field, and ACCESS4_EXECUTE is not set in the reply's		field, and ACCESS4_EXECUTE is not set in the reply's
	supported field, then the client will have to send		supported field, then the client will have to send
	an ACCESS request with the ACCESS4_READ bit set in		an ACCESS request with the ACCESS4_READ bit set in
	the request's access field.		the request's access field.
	</t>		</li>
			<li>
	<t>		If the server supports read permission bits, it <bcp14>MUST</bcp14>
	If the server supports read permission bits, it MUST
	only check for read permissions in the mode, acl,		only check for read permissions in the mode, acl,
	and dacl attributes when it receives an ACCESS request		and dacl attributes when it receives an ACCESS request
	with ACCESS4_READ set in the access field. The server		with ACCESS4_READ set in the access field. The server
	MUST NOT also examine execute permission bits when		<bcp14>MUST NOT</bcp14> also examine execute permission bits when
	determining whether the reply will have ACCESS4_READ		determining whether the reply will have ACCESS4_READ
	set in the access field or not.		set in the access field or not.
	</t>		</li>
			</ul>
	</list>		<t>
	Note that if the ACCESS reply has ACCESS4_READ		Note that if the ACCESS reply has ACCESS4_READ
	or ACCESS_EXECUTE set, then the user also has		or ACCESS_EXECUTE set, then the user also has
	permissions to OPEN (<xref target="OP_OPEN"/>) or		permissions to OPEN (<xref target="OP_OPEN" format="default"/>) or
	READ (<xref target="OP_READ"/>) the file. In other words, if		READ (<xref target="OP_READ" format="default"/>) the file. In other words, if
	the client sends an ACCESS request with the ACCESS4_READ		the client sends an ACCESS request with the ACCESS4_READ
	and ACCESS_EXECUTE set in the access field (or two		and ACCESS_EXECUTE set in the access field (or two
	separate requests, one with ACCESS4_READ set and the		separate requests, one with ACCESS4_READ set and the
	other with ACCESS4_EXECUTE set), and the reply has		other with ACCESS4_EXECUTE set), and the reply has
	just ACCESS4_EXECUTE set in the access field (or just		just ACCESS4_EXECUTE set in the access field (or just
	one reply has ACCESS4_EXECUTE set), then the user has		one reply has ACCESS4_EXECUTE set), then the user has
	authorization to OPEN or READ the file.		authorization to OPEN or READ the file.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_ACCESS_IMPLEMENTATION" title="IMPLEMENTATION		<section toc="exclude" anchor="OP_ACCESS_IMPLEMENTATION" numbered="true"
	">		>
	<t>		<name>IMPLEMENTATION</name>
			<t>
	In general, it is not sufficient for the client to attempt to deduce		In general, it is not sufficient for the client to attempt to deduce
	access permissions by inspecting the uid, gid, and mode fields in the		access permissions by inspecting the uid, gid, and mode fields in the
	file attributes or by attempting to interpret the contents of the ACL		file attributes or by attempting to interpret the contents of the ACL
	attribute. This is because the server may perform uid or gid mapping		attribute. This is because the server may perform uid or gid mapping
	or enforce additional access-control restrictions. It is also		or enforce additional access-control restrictions. It is also
	possible that the server may not be in the same ID space as the		possible that the server may not be in the same ID space as the
	client. In these cases (and perhaps others), the client cannot		client. In these cases (and perhaps others), the client cannot
	reliably perform an access check with only current file attributes.		reliably perform an access check with only current file attributes.
	</t>		</t>
	<t>		<t>
	In the NFSv2 protocol, the only reliable way to determine		In the NFSv2 protocol, the only reliable way to determine
	whether an operation was allowed was to try it and see if it succeeded		whether an operation was allowed was to try it and see if it succeeded
	or failed. Using the ACCESS operation in the NFSv4.1 protocol,		or failed. Using the ACCESS operation in the NFSv4.1 protocol,
	the client can ask the server to indicate whether or not one or more		the client can ask the server to indicate whether or not one or more
	classes of operations are permitted. The ACCESS operation is provided		classes of operations are permitted. The ACCESS operation is provided
	to allow clients to check before doing a series of operations that		to allow clients to check before doing a series of operations that
	will result in an access failure. The OPEN operation provides a point		will result in an access failure. The OPEN operation provides a point
	where the server can verify access to the file object and a method to		where the server can verify access to the file object and a method to
	return that information to the client. The ACCESS operation is still		return that information to the client. The ACCESS operation is still
	useful for directory operations or for use in the case that the UNIX interface		useful for directory operations or for use in the case that the UNIX interface
	access() is used on the client.		access() is used on the client.
	</t>		</t>
	<t>		<t>
	The information returned by the server in response to an ACCESS call		The information returned by the server in response to an ACCESS call
	is not permanent. It was correct at the exact time that the server		is not permanent. It was correct at the exact time that the server
	performed the checks, but not necessarily afterwards. The server can		performed the checks, but not necessarily afterwards. The server can
	revoke access permission at any time.		revoke access permission at any time.
	</t>		</t>
	<t>		<t>
	The client should use the effective credentials of the user to build		The client should use the effective credentials of the user to build
	the authentication information in the ACCESS request used to determine		the authentication information in the ACCESS request used to determine
	access rights. It is the effective user and group credentials that		access rights. It is the effective user and group credentials that
	are used in subsequent READ and WRITE operations.		are used in subsequent READ and WRITE operations.
	</t>		</t>
	<t>		<t>
	Many implementations do not directly support the ACCESS4_DELETE		Many implementations do not directly support the ACCESS4_DELETE
	permission. Operating systems like UNIX will ignore the ACCESS4_DELETE		permission. Operating systems like UNIX will ignore the ACCESS4_DELETE
	bit if set on an access request on a non-directory object. In these		bit if set on an access request on a non-directory object. In these
	systems, delete permission on a file is determined by the access		systems, delete permission on a file is determined by the access
	permissions on the directory in which the file resides, instead of		permissions on the directory in which the file resides, instead of
	being determined by the permissions of the file itself. Therefore,		being determined by the permissions of the file itself. Therefore,
	the mask returned enumerating which access rights can be determined		the mask returned enumerating which access rights can be determined
	will have the ACCESS4_DELETE value set to 0. This indicates to the		will have the ACCESS4_DELETE value set to 0. This indicates to the
	client that the server was unable to check that particular access		client that the server was unable to check that particular access
	right. The ACCESS4_DELETE bit in the access mask returned will then be		right. The ACCESS4_DELETE bit in the access mask returned will then be
	ignored by the client.		ignored by the client.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		<section anchor="OP_CLOSE" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 4: CLOSE - Close File</name>
	$ -->		<section toc="exclude" anchor="OP_CLOSE_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The IETF Trust (2007) -->		<name>ARGUMENTS</name>
	<!-- Copyright (C) The Internet Society (2006) -->		<sourcecode type="xdr"><![CDATA[
	<section anchor="OP_CLOSE" title="Operation 4: CLOSE - Close File" >
	<section toc="exclude" anchor="OP_CLOSE_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct CLOSE4args {		struct CLOSE4args {
	/* CURRENT_FH: object */		/* CURRENT_FH: object */
	seqid4 seqid;		seqid4 seqid;
	stateid4 open_stateid;		stateid4 open_stateid;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_CLOSE_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_CLOSE_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	union CLOSE4res switch (nfsstat4 status) {		union CLOSE4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	stateid4 open_stateid;		stateid4 open_stateid;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_CLOSE_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_CLOSE_DESCRIPTION" title="DESCRIPTION">
	<t>
	The CLOSE operation releases share reservations for the regular or		The CLOSE operation releases share reservations for the regular or
	named attribute file as specified by the current filehandle. The		named attribute file as specified by the current filehandle. The
	share reservations and other state information released at the server		share reservations and other state information released at the server
	as a result of this CLOSE are only those associated with the supplied		as a result of this CLOSE are only those associated with the supplied
	stateid. State associated with other OPENs is not affected.		stateid. State associated with other OPENs is not affected.
	</t>		</t>
	<t>		<t>
	If byte-range locks are held, the client SHOULD release all locks before		If byte-range locks are held, the client <bcp14>SHOULD</bcp14> release all
	sending a CLOSE. The server MAY free all outstanding locks on CLOSE,		locks before
			sending a CLOSE. The server <bcp14>MAY</bcp14> free all outstanding locks
			on CLOSE,
	but some servers may not support the CLOSE of a file that still has		but some servers may not support the CLOSE of a file that still has
	byte-range locks held. The server MUST return failure if any locks would		byte-range locks held. The server <bcp14>MUST</bcp14> return failure if a ny locks would
	exist after the CLOSE.		exist after the CLOSE.
	</t>		</t>
	<t>		<t>
	The argument seqid MAY have any value, and the server MUST ignore seqid.		The argument seqid <bcp14>MAY</bcp14> have any value, and the server <bcp1
	</t>		4>MUST</bcp14> ignore seqid.
	<t>		</t>
			<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	<t>		<t>
	The server MAY require that the combination of principal, security		The server <bcp14>MAY</bcp14> require that the combination of principal, se
			curity
	flavor, and, if applicable, GSS mechanism		flavor, and, if applicable, GSS mechanism
	that sent the OPEN request also be the one to CLOSE		that sent the OPEN request also be the one to CLOSE
	the file. This might not be possible if credentials		the file. This might not be possible if credentials
	for the principal are no longer available. The server		for the principal are no longer available. The server
	MAY allow the machine credential or SSV credential		<bcp14>MAY</bcp14> allow the machine credential or SSV credential
	(see <xref target="OP_EXCHANGE_ID" />) to send CLOSE.		(see <xref target="OP_EXCHANGE_ID" format="default"/>) to send CLOSE.
	</t>
	</section>		</t>
	<section toc="exclude" anchor="OP_CLOSE_IMPLEMENTATION" title="IMPLEMENTATION"		</section>
	>		<section toc="exclude" anchor="OP_CLOSE_IMPLEMENTATION" numbered="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	Even though CLOSE returns a stateid, this stateid is not useful to the		Even though CLOSE returns a stateid, this stateid is not useful to the
	client and should be treated as deprecated. CLOSE "shuts down" the		client and should be treated as deprecated. CLOSE "shuts down" the
	state associated with all OPENs for the file by a single open-owner.		state associated with all OPENs for the file by a single open-owner.
	As noted above, CLOSE will either release all file-locking state or		As noted above, CLOSE will either release all file-locking state or
	return an error. Therefore, the stateid returned by CLOSE is not		return an error. Therefore, the stateid returned by CLOSE is not
	useful for operations that follow. To help find any uses of		useful for operations that follow. To help find any uses of
	this stateid by clients, the server SHOULD return the invalid		this stateid by clients, the server <bcp14>SHOULD</bcp14> return the inval id
	special stateid (the "other" value is zero and the "seqid" field		special stateid (the "other" value is zero and the "seqid" field
	is NFS4_UINT32_MAX, see <xref target="special_stateid"/>).		is NFS4_UINT32_MAX, see <xref target="special_stateid" format="default"/>)
	</t>		.
	<t>		</t>
			<t>
	A CLOSE operation may make delegations grantable		A CLOSE operation may make delegations grantable
	where they were not previously. Servers may choose to respond		where they were not previously. Servers may choose to respond
	immediately if there are pending delegation want requests or may		immediately if there are pending delegation want requests or may
	respond to the situation at a later time.		respond to the situation at a later time.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="OP_COMMIT" numbered="true" toc="default">
	<section anchor="OP_COMMIT" title="Operation 5: COMMIT - Commit Cached Data" >		<name>Operation 5: COMMIT - Commit Cached Data</name>
			<section toc="exclude" anchor="OP_COMMIT_ARGUMENTS" numbered="true">
	<section toc="exclude" anchor="OP_COMMIT_ARGUMENTS" title="ARGUMENTS">		<name>ARGUMENTS</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct COMMIT4args {		struct COMMIT4args {
	/* CURRENT_FH: file */		/* CURRENT_FH: file */
	offset4 offset;		offset4 offset;
	count4 count;		count4 count;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_COMMIT_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_COMMIT_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct COMMIT4resok {		struct COMMIT4resok {
	verifier4 writeverf;		verifier4 writeverf;
	};		};
	union COMMIT4res switch (nfsstat4 status) {		union COMMIT4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	COMMIT4resok resok4;		COMMIT4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_COMMIT_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_COMMIT_DESCRIPTION" title="DESCRIPTION">
	<t>
	The COMMIT operation forces or flushes uncommitted, modified data to stabl e storage for the		The COMMIT operation forces or flushes uncommitted, modified data to stabl e storage for the
	file specified by the current filehandle. The flushed data is that		file specified by the current filehandle. The flushed data is that
	which was previously written with one or more WRITE operations that had th e		which was previously written with one or more WRITE operations that had th e
	"committed" field of their results field set to UNSTABLE4.		"committed" field of their results field set to UNSTABLE4.
	</t>		</t>
	<t>		<t>
	The offset specifies the position within the file where the flush is		The offset specifies the position within the file where the flush is
	to begin. An offset value of zero means to flush data starting at		to begin. An offset value of zero means to flush data starting at
	the beginning of the file. The count specifies the number of bytes of		the beginning of the file. The count specifies the number of bytes of
	data to flush. If the count is zero, a flush from the offset to the end		data to flush. If the count is zero, a flush from the offset to the end
	of the file is done.		of the file is done.
	</t>		</t>
	<t>		<t>
	The server returns a write verifier upon successful completion of the		The server returns a write verifier upon successful completion of the
	COMMIT. The write verifier is used by the client to determine if the		COMMIT. The write verifier is used by the client to determine if the
	server has restarted between the initial WRITE operations and the		server has restarted between the initial WRITE operations and the
	COMMIT. The client does this by comparing the write verifier returned		COMMIT. The client does this by comparing the write verifier returned
	from the initial WRITE operations and the verifier returned by the COMMIT		from the initial WRITE operations and the verifier returned by the COMMIT
	operation. The server must vary the value of the write verifier at		operation. The server must vary the value of the write verifier at
	each server event or instantiation that may lead to a loss of		each server event or instantiation that may lead to a loss of
	uncommitted data. Most commonly this occurs when the server is		uncommitted data. Most commonly this occurs when the server is
	restarted; however, other events at the server may result in		restarted; however, other events at the server may result in
	uncommitted data loss as well.		uncommitted data loss as well.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_COMMIT_IMPLEMENTATION" title="IMPLEMENTATION		<section toc="exclude" anchor="OP_COMMIT_IMPLEMENTATION" numbered="true"
	">		>
	<t>		<name>IMPLEMENTATION</name>
			<t>
	The COMMIT operation is similar in operation and semantics to the		The COMMIT operation is similar in operation and semantics to the
	<xref target="fsync">POSIX fsync()</xref> system interface that synchroniz es a file's state with the		<xref target="fsync" format="default">POSIX fsync()</xref> system interfac e that synchronizes a file's state with the
	disk (file data and metadata is flushed to disk or stable		disk (file data and metadata is flushed to disk or stable
	storage). COMMIT performs the same operation for a client, flushing		storage). COMMIT performs the same operation for a client, flushing
	any unsynchronized data and metadata on the server to the server's		any unsynchronized data and metadata on the server to the server's
	disk or stable storage for the specified file. Like fsync(), it may		disk or stable storage for the specified file. Like fsync(), it may
	be that there is some modified data or no modified data to		be that there is some modified data or no modified data to
	synchronize. The data may have been synchronized by the server's		synchronize. The data may have been synchronized by the server's
	normal periodic buffer synchronization activity. COMMIT should return		normal periodic buffer synchronization activity. COMMIT should return
	NFS4_OK, unless there has been an unexpected error.		NFS4_OK, unless there has been an unexpected error.
	</t>		</t>
	<t>		<t>
	COMMIT differs from fsync() in that it is possible for the client to		COMMIT differs from fsync() in that it is possible for the client to
	flush a range of the file (most likely triggered by a		flush a range of the file (most likely triggered by a
	buffer-reclamation scheme on the client before the file has been		buffer-reclamation scheme on the client before the file has been
	completely written).		completely written).
	</t>		</t>
	<t>		<t>
	The server implementation of COMMIT is reasonably simple. If the		The server implementation of COMMIT is reasonably simple. If the
	server receives a full file COMMIT request, that is, starting at offset		server receives a full file COMMIT request, that is, starting at offset
	zero and count zero, it should do the equivalent of applying fsync() to		zero and count zero, it should do the equivalent of applying fsync() to
	the entire file.		the entire file.
	Otherwise, it should arrange to have the modified data in the range		Otherwise, it should arrange to have the modified data in the range
	specified by offset and count to be flushed to stable storage. In		specified by offset and count to be flushed to stable storage. In
	both cases, any metadata associated with the file must be flushed to		both cases, any metadata associated with the file must be flushed to
	stable storage before returning. It is not an error for there to be		stable storage before returning. It is not an error for there to be
	nothing to flush on the server. This means that the data and metadata		nothing to flush on the server. This means that the data and metadata
	that needed to be flushed have already been flushed or lost during the		that needed to be flushed have already been flushed or lost during the
	last server failure.		last server failure.
	</t>		</t>
	<t>		<t>
	The client implementation of COMMIT is a little more complex. There		The client implementation of COMMIT is a little more complex. There
	are two reasons for wanting to commit a client buffer to stable		are two reasons for wanting to commit a client buffer to stable
	storage. The first is that the client wants to reuse a buffer. In		storage. The first is that the client wants to reuse a buffer. In
	this case, the offset and count of the buffer are sent to the server		this case, the offset and count of the buffer are sent to the server
	in the COMMIT request. The server then flushes any modified data based		in the COMMIT request. The server then flushes any modified data based
	on the offset and count, and flushes any modified metadata associated with the		on the offset and count, and flushes any modified metadata associated with the
	file. It then returns the status of the flush and the write verifier.		file. It then returns the status of the flush and the write verifier.
	The second reason for the client to generate a COMMIT is for a full		The second reason for the client to generate a COMMIT is for a full
	file flush, such as may be done at close. In this case, the client		file flush, such as may be done at close. In this case, the client
	would gather all of the buffers for this file that contain uncommitted		would gather all of the buffers for this file that contain uncommitted
	data, do the COMMIT operation with an offset of zero and count of zero, an d		data, do the COMMIT operation with an offset of zero and count of zero, an d
	then free all of those buffers. Any other dirty buffers would be sent		then free all of those buffers. Any other dirty buffers would be sent
	to the server in the normal fashion.		to the server in the normal fashion.
	</t>		</t>
	<t>		<t>
	After a buffer is written (via the WRITE operation)		After a buffer is written (via the WRITE operation)
	by the client with the "committed" field in the result of WRITE		by the client with the "committed" field in the result of WRITE
	set to UNSTABLE4, the buffer must be considered as modified by		set to UNSTABLE4, the buffer must be considered as modified by
	the client		the client
	until the buffer has either been flushed via a COMMIT operation or		until the buffer has either been flushed via a COMMIT operation or
	written via a WRITE operation with the "committed" field in the		written via a WRITE operation with the "committed" field in the
	result set to FILE_SYNC4		result set to FILE_SYNC4
	or DATA_SYNC4. This is done to prevent the buffer from being freed and		or DATA_SYNC4. This is done to prevent the buffer from being freed and
	reused before the data can be flushed to stable storage on the server.		reused before the data can be flushed to stable storage on the server.
	</t>		</t>
	<t>		<t>
	When a response is returned from either a WRITE or a COMMIT operation		When a response is returned from either a WRITE or a COMMIT operation
	and it contains a write verifier that differs from that previously		and it contains a write verifier that differs from that previously
	returned by the server, the client will need to retransmit all of the		returned by the server, the client will need to retransmit all of the
	buffers containing uncommitted data to the server. How this is		buffers containing uncommitted data to the server. How this is
	to be done is up to the implementor. If there is only one buffer of		to be done is up to the implementor. If there is only one buffer of
	interest, then it should be sent in a WRITE request		interest, then it should be sent in a WRITE request
	with the FILE_SYNC4 stable parameter. If there is more than one		with the FILE_SYNC4 stable parameter. If there is more than one
	buffer, it might be worthwhile retransmitting all of the buffers in		buffer, it might be worthwhile retransmitting all of the buffers in
	WRITE operations with the stable parameter set to UNSTABLE4 and then		WRITE operations with the stable parameter set to UNSTABLE4 and then
	retransmitting the COMMIT operation to flush all of the data on the		retransmitting the COMMIT operation to flush all of the data on the
	server to stable storage. However, if the server repeatably		server to stable storage. However, if the server repeatably
	returns from COMMIT a verifier that differs from that returned		returns from COMMIT a verifier that differs from that returned
	by WRITE, the only way to ensure progress is to retransmit all		by WRITE, the only way to ensure progress is to retransmit all
	of the buffers with WRITE requests with the FILE_SYNC4 stable parameter.		of the buffers with WRITE requests with the FILE_SYNC4 stable parameter.
	</t>		</t>
	<t>		<t>
	The above description applies to page-cache-based systems as well as		The above description applies to page-cache-based systems as well as
	buffer-cache-based systems. In the former systems, the virtual memory		buffer-cache-based systems. In the former systems, the virtual memory
	system will need to be modified instead of the buffer cache.		system will need to be modified instead of the buffer cache.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_CREATE" numbered="true" toc="default">
	$ -->		<name>Operation 6: CREATE - Create a Non-Regular File Object</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_CREATE_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_CREATE" title="Operation 6: CREATE - Create a Non-Regular Fi		<sourcecode type="xdr"><![CDATA[
	le Object" >
	<section toc="exclude" anchor="OP_CREATE_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	union createtype4 switch (nfs_ftype4 type) {		union createtype4 switch (nfs_ftype4 type) {
	case NF4LNK:		case NF4LNK:
	linktext4 linkdata;		linktext4 linkdata;
	case NF4BLK:		case NF4BLK:
	case NF4CHR:		case NF4CHR:
	specdata4 devdata;		specdata4 devdata;
	case NF4SOCK:		case NF4SOCK:
	case NF4FIFO:		case NF4FIFO:
	case NF4DIR:		case NF4DIR:
	void;		void;
	default:		default:
	void; /* server should return NFS4ERR_BADTYPE */		void; /* server should return NFS4ERR_BADTYPE */
	};		};
	struct CREATE4args {		struct CREATE4args {
	/* CURRENT_FH: directory for creation */		/* CURRENT_FH: directory for creation */
	createtype4 objtype;		createtype4 objtype;
	component4 objname;		component4 objname;
	fattr4 createattrs;		fattr4 createattrs;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_CREATE_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_CREATE_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct CREATE4resok {		struct CREATE4resok {
	change_info4 cinfo;		change_info4 cinfo;
	bitmap4 attrset; /* attributes set */		bitmap4 attrset; /* attributes set */
	};		};
	union CREATE4res switch (nfsstat4 status) {		union CREATE4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	/* new CURRENTFH: created object */		/* new CURRENTFH: created object */
	CREATE4resok resok4;		CREATE4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_CREATE_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_CREATE_DESCRIPTION" title="DESCRIPTION">
	<t>
	The CREATE operation creates a file object other than an		The CREATE operation creates a file object other than an
	ordinary file in a directory with a given name.		ordinary file in a directory with a given name.
	The OPEN operation MUST be used to create a		The OPEN operation <bcp14>MUST</bcp14> be used to create a
	regular file or a named attribute.		regular file or a named attribute.
	</t>		</t>
	<t>		<t>
	The current filehandle must be a directory: an object of type NF4DIR. If the current		The current filehandle must be a directory: an object of type NF4DIR. If the current
	filehandle is an attribute directory (type NF4ATTRDIR), the		filehandle is an attribute directory (type NF4ATTRDIR), the
	error NFS4ERR_WRONG_TYPE is returned. If the current file handle		error NFS4ERR_WRONG_TYPE is returned. If the current filehandle
	designates any other type of object, the error NFS4ERR_NOTDIR		designates any other type of object, the error NFS4ERR_NOTDIR
	results.		results.
	</t>		</t>
	<t>		<t>
	The objname specifies the name for the new object.		The objname specifies the name for the new object.
	The objtype determines the type of object to be		The objtype determines the type of object to be
	created: directory, symlink, etc. If the object		created: directory, symlink, etc. If the object
	type specified is that of an ordinary file, a		type specified is that of an ordinary file, a
	named attribute, or a named attribute directory,		named attribute, or a named attribute directory,
	the error NFS4ERR_BADTYPE results.		the error NFS4ERR_BADTYPE results.
	</t>		</t>
	<t>		<t>
	If an object of the same name already exists in the directory, the		If an object of the same name already exists in the directory, the
	server will return the error NFS4ERR_EXIST.		server will return the error NFS4ERR_EXIST.
	</t>		</t>
	<t>		<t>
	For the directory where the new file object was created, the server		For the directory where the new file object was created, the server
	returns change_info4 information in cinfo. With the atomic field of		returns change_info4 information in cinfo. With the atomic field of
	the change_info4 data type, the server will indicate if the before and		the change_info4 data type, the server will indicate if the before and
	after change attributes were obtained atomically with respect to the		after change attributes were obtained atomically with respect to the
	file object creation.		file object creation.
	</t>		</t>
	<t>		<t>
	If the objname has a length of zero, or if objname does not obey		If the objname has a length of zero, or if objname does not obey
	the UTF-8 definition, the error NFS4ERR_INVAL will be returned.		the UTF-8 definition, the error NFS4ERR_INVAL will be returned.
	</t>		</t>
	<t>		<t>
	The current filehandle is replaced by that of the new object.		The current filehandle is replaced by that of the new object.
	</t>		</t>
	<t>		<t>
	The createattrs specifies the initial set of attributes for the		The createattrs specifies the initial set of attributes for the
	object. The set of attributes may include any writable attribute		object. The set of attributes may include any writable attribute
	valid for the object type. When the operation is successful, the		valid for the object type. When the operation is successful, the
	server will return to the client an attribute mask signifying which		server will return to the client an attribute mask signifying which
	attributes were successfully set for the object.		attributes were successfully set for the object.
	</t>		</t>
	<t>		<t>
	If createattrs includes neither the owner attribute nor an ACL with an		If createattrs includes neither the owner attribute nor an ACL with an
	ACE for the owner, and if the server's file system both supports and		ACE for the owner, and if the server's file system both supports and
	requires an owner attribute (or an owner ACE), then the server MUST		requires an owner attribute (or an owner ACE), then the server <bcp14>MUST </bcp14>
	derive the owner (or the owner ACE). This would typically be from the		derive the owner (or the owner ACE). This would typically be from the
	principal indicated in the RPC credentials of the call, but the		principal indicated in the RPC credentials of the call, but the
	server's operating environment or file system semantics may dictate		server's operating environment or file system semantics may dictate
	other methods of derivation. Similarly, if createattrs includes		other methods of derivation. Similarly, if createattrs includes
	neither the group attribute nor a group ACE, and if the server's		neither the group attribute nor a group ACE, and if the server's
	file system both supports and requires the notion of a group attribute		file system both supports and requires the notion of a group attribute
	(or group ACE), the server MUST derive the group attribute (or the		(or group ACE), the server <bcp14>MUST</bcp14> derive the group attribute (or the
	corresponding owner ACE) for the file. This could be from the RPC		corresponding owner ACE) for the file. This could be from the RPC
	call's credentials, such as the group principal if the credentials		call's credentials, such as the group principal if the credentials
	include it (such as with AUTH_SYS), from the group identifier		include it (such as with AUTH_SYS), from the group identifier
	associated with the principal in the credentials (e.g., POSIX		associated with the principal in the credentials (e.g., POSIX
	systems have a <xref target="passwd">user database</xref> that has a group identifier for every		systems have a <xref target="passwd" format="default">user database</xref> that has a group identifier for every
	user identifier), inherited from the directory in which the object is crea ted,		user identifier), inherited from the directory in which the object is crea ted,
	or whatever else the server's operating environment or file system		or whatever else the server's operating environment or file system
	semantics dictate. This applies to the OPEN operation too.		semantics dictate. This applies to the OPEN operation too.
	</t>		</t>
	<t>		<t>
	Conversely, it is possible that the client will specify in createattrs an		Conversely, it is possible that the client will specify in createattrs an
	owner attribute, group attribute, or ACL that the principal indicated		owner attribute, group attribute, or ACL that the principal indicated
	the RPC call's credentials does not have permissions to create files		the RPC call's credentials does not have permissions to create files
	for. The error to be returned in this instance is NFS4ERR_PERM. This		for. The error to be returned in this instance is NFS4ERR_PERM. This
	applies to the OPEN operation too.		applies to the OPEN operation too.
	</t>		</t>
	<t>		<t>
	If the current filehandle designates a directory for which another		If the current filehandle designates a directory for which another
	client holds a directory delegation, then, unless the delegation		client holds a directory delegation, then, unless the delegation
	is such that the situation can be resolved by sending a notification,		is such that the situation can be resolved by sending a notification,
	the delegation MUST be recalled, and the CREATE operation MUST NOT proceed		the delegation <bcp14>MUST</bcp14> be recalled, and the CREATE operation < bcp14>MUST NOT</bcp14> proceed
	until the delegation is returned or revoked. Except where this		until the delegation is returned or revoked. Except where this
	happens very quickly, one or more NFS4ERR_DELAY errors will be		happens very quickly, one or more NFS4ERR_DELAY errors will be
	returned to requests made while delegation remains outstanding.		returned to requests made while delegation remains outstanding.
	</t>		</t>
	<t>		<t>
	When the current filehandle designates a directory for which		When the current filehandle designates a directory for which
	one or more directory delegations exist, then, when those delegations		one or more directory delegations exist, then, when those delegations
	request such notifications, NOTIFY4_ADD_ENTRY will be generated		request such notifications, NOTIFY4_ADD_ENTRY will be generated
	as a result of this operation.		as a result of this operation.
	</t>		</t>
	<t>		<t>
	If the capability FSCHARSET_CAP4_ALLOWS_ONLY_UTF8 is set		If the capability FSCHARSET_CAP4_ALLOWS_ONLY_UTF8 is set
	(<xref target="utf8_caps"/>),		(<xref target="utf8_caps" format="default"/>),
	and a symbolic link is being created, then the content		and a symbolic link is being created, then the content
	of the symbolic link MUST be in UTF-8 encoding.		of the symbolic link <bcp14>MUST</bcp14> be in UTF-8 encoding.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_CREATE_IMPLEMENTATION" title="IMPLEMENTATION		<section toc="exclude" anchor="OP_CREATE_IMPLEMENTATION" numbered="true"
	">		>
	<t>		<name>IMPLEMENTATION</name>
			<t>
	If the client desires to set attribute values after the create, a		If the client desires to set attribute values after the create, a
	SETATTR operation can be added to the COMPOUND request so that the		SETATTR operation can be added to the COMPOUND request so that the
	appropriate attributes will be set.		appropriate attributes will be set.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_DELEGPURGE" numbered="true" toc="default">
	$ -->		<name>Operation 7: DELEGPURGE - Purge Delegations Awaiting Recovery</nam
	<!-- Copyright (C) The IETF Trust (2007) -->		e>
	<!-- Copyright (C) The Internet Society (2006) -->		<section toc="exclude" anchor="OP_DELEGPURGE_ARGUMENTS" numbered="true">
	<section anchor="OP_DELEGPURGE" title="Operation 7: DELEGPURGE - Purge Delegatio		<name>ARGUMENTS</name>
	ns Awaiting Recovery" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_DELEGPURGE_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct DELEGPURGE4args {		struct DELEGPURGE4args {
	clientid4 clientid;		clientid4 clientid;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_DELEGPURGE_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_DELEGPURGE_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct DELEGPURGE4res {		struct DELEGPURGE4res {
	nfsstat4 status;		nfsstat4 status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_DELEGPURGE_DESCRIPTION" numbered="true
	</figure>		">
	</section>		<name>DESCRIPTION</name>
			<t>
	<section toc="exclude" anchor="OP_DELEGPURGE_DESCRIPTION" title="DESCRIPTION">
	<t>
	This operation purges all of the delegations awaiting recovery for a given client.		This operation purges all of the delegations awaiting recovery for a given client.
	This is useful for clients that do not commit delegation information		This is useful for clients that do not commit delegation information
	to stable storage to indicate that conflicting requests need not be		to stable storage to indicate that conflicting requests need not be
	delayed by the server awaiting recovery of delegation information.		delayed by the server awaiting recovery of delegation information.
	</t>		</t>
	<t>		<t>
	The client is NOT specified by the clientid field of		The client is NOT specified by the clientid field of
	the request. The client SHOULD set the client field		the request. The client <bcp14>SHOULD</bcp14> set the client field
	to zero, and the server MUST ignore the clientid		to zero, and the server <bcp14>MUST</bcp14> ignore the clientid
	field. Instead, the server MUST derive the client ID		field. Instead, the server <bcp14>MUST</bcp14> derive the client ID
	from the value of the session ID in the arguments of		from the value of the session ID in the arguments of
	the SEQUENCE operation that precedes DELEGPURGE in		the SEQUENCE operation that precedes DELEGPURGE in
	the COMPOUND request.		the COMPOUND request.
	</t>		</t>
			<t>
	<t>
	The DELEGPURGE operation should be used by clients that record delegation		The DELEGPURGE operation should be used by clients that record delegation
	information on stable storage on the client. In this case,		information on stable storage on the client. In this case,
	after the client recovers all delegations it knows of,		after the client recovers all delegations it knows of,
	it should immediately send a DELEGPURGE operation.		it should immediately send a DELEGPURGE operation.
	Doing so will notify the server that		Doing so will notify the server that
	no additional delegations for the client will be recovered allowing it		no additional delegations for the client will be recovered allowing it
	to free resources, and avoid delaying other clients which make requests		to free resources, and avoid delaying other clients which make requests
	that conflict with the unrecovered delegations. The set of		that conflict with the unrecovered delegations. The set of
	delegations known to the server and the client might be different. The		delegations known to the server and the client might be different. The
	reason for this is that after sending a request that		reason for this is that after sending a request that
	resulted in a delegation, the client might experience a failure		resulted in a delegation, the client might experience a failure
	before it both received the delegation and		before it both received the delegation and
	committed the delegation to the client's stable storage.		committed the delegation to the client's stable storage.
	</t>		</t>
	<t>		<t>
	The server MAY support DELEGPURGE, but if it does not, it MUST NOT		The server <bcp14>MAY</bcp14> support DELEGPURGE, but if it does not, it <
	support CLAIM_DELEGATE_PREV and MUST NOT support CLAIM_DELEG_PREV_FH.		bcp14>MUST NOT</bcp14>
	</t>		support CLAIM_DELEGATE_PREV and <bcp14>MUST NOT</bcp14> support CLAIM_DELE
	</section>		G_PREV_FH.
	</section>		</t>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		</section>
	$ -->		</section>
	<!-- Copyright (C) The IETF Trust (2007) -->		<section anchor="OP_DELEGRETURN" numbered="true" toc="default">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>Operation 8: DELEGRETURN - Return Delegation</name>
	<section anchor="OP_DELEGRETURN" title="Operation 8: DELEGRETURN - Return Delega		<section toc="exclude" anchor="OP_DELEGRETURN_ARGUMENTS" numbered="true"
	tion" >		>
			<name>ARGUMENTS</name>
	<section toc="exclude" anchor="OP_DELEGRETURN_ARGUMENTS" title="ARGUMENTS">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct DELEGRETURN4args {		struct DELEGRETURN4args {
	/* CURRENT_FH: delegated object */		/* CURRENT_FH: delegated object */
	stateid4 deleg_stateid;		stateid4 deleg_stateid;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_DELEGRETURN_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_DELEGRETURN_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct DELEGRETURN4res {		struct DELEGRETURN4res {
	nfsstat4 status;		nfsstat4 status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_DELEGRETURN_DESCRIPTION" numbered="tru
	</figure>		e">
	</section>		<name>DESCRIPTION</name>
			<t>
	<section toc="exclude" anchor="OP_DELEGRETURN_DESCRIPTION" title="DESCRIPTION"
	>
	<t>
	The DELEGRETURN operation returns the delegation represented by		The DELEGRETURN operation returns the delegation represented by
	the current filehandle and stateid.		the current filehandle and stateid.
	</t>		</t>
	<t>		<t>
	Delegations may be returned voluntarily (i.e., before		Delegations may be returned voluntarily (i.e., before
	the server has recalled them) or when recalled. In either case, the clien t must		the server has recalled them) or when recalled. In either case, the clien t must
	properly propagate state changed under the context of the delegation to		properly propagate state changed under the context of the delegation to
	the server before returning the delegation.		the server before returning the delegation.
	</t>		</t>
	<t>		<t>
	The server MAY require that the principal, security		The server <bcp14>MAY</bcp14> require that the principal, security
	flavor, and if applicable, the GSS mechanism, combination		flavor, and if applicable, the GSS mechanism, combination
	that acquired the delegation also be the one to send		that acquired the delegation also be the one to send
	DELEGRETURN on the file. This might not be possible		DELEGRETURN on the file. This might not be possible
	if credentials for the principal are no longer		if credentials for the principal are no longer
	available. The server MAY allow the machine credential		available. The server <bcp14>MAY</bcp14> allow the machine credential
	or SSV credential (see <xref target="OP_EXCHANGE_ID"		or SSV credential (see <xref target="OP_EXCHANGE_ID" format="default"/>) to
	/>) to send DELEGRETURN.		send DELEGRETURN.
	</t>
	</section>
	</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->
	<!-- Copyright (C) The IETF Trust (2007-2008) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="OP_GETATTR" title="Operation 9: GETATTR - Get Attributes" >
	<section toc="exclude" anchor="OP_GETATTR_ARGUMENTS" title="ARGUMENTS">		</t>
	<figure>		</section>
	<artwork>		</section>
			<section anchor="OP_GETATTR" numbered="true" toc="default">
			<name>Operation 9: GETATTR - Get Attributes</name>
			<section toc="exclude" anchor="OP_GETATTR_ARGUMENTS" numbered="true">
			<name>ARGUMENTS</name>
			<sourcecode type="xdr"><![CDATA[
	struct GETATTR4args {		struct GETATTR4args {
	/* CURRENT_FH: object */		/* CURRENT_FH: object */
	bitmap4 attr_request;		bitmap4 attr_request;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_GETATTR_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_GETATTR_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct GETATTR4resok {		struct GETATTR4resok {
	fattr4 obj_attributes;		fattr4 obj_attributes;
	};		};
	union GETATTR4res switch (nfsstat4 status) {		union GETATTR4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	GETATTR4resok resok4;		GETATTR4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_GETATTR_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_GETATTR_DESCRIPTION" title="DESCRIPTION">
	<t>
	The GETATTR operation will obtain attributes for the file system		The GETATTR operation will obtain attributes for the file system
	object specified by the current filehandle. The client sets a bit in		object specified by the current filehandle. The client sets a bit in
	the bitmap argument for each attribute value that it would like the		the bitmap argument for each attribute value that it would like the
	server to return. The server returns an attribute bitmap that		server to return. The server returns an attribute bitmap that
	indicates the attribute values that it was able to return,		indicates the attribute values that it was able to return,
	which will include all attributes requested by the client that		which will include all attributes requested by the client that
	are attributes supported by the server for the target		are attributes supported by the server for the target
	file system. This bitmap is followed by the attribute values ordered		file system. This bitmap is followed by the attribute values ordered
	lowest attribute number first.		lowest attribute number first.
	</t>		</t>
	<t>		<t>
	The server MUST return a value for each attribute that the client		The server <bcp14>MUST</bcp14> return a value for each attribute that the
			client
	requests if the attribute is supported by the server for the target		requests if the attribute is supported by the server for the target
	file system. If the server does not support a particular attribute		file system. If the server does not support a particular attribute
	on the target file system, then it MUST NOT return the attribute value		on the target file system, then it <bcp14>MUST NOT</bcp14> return the attr
	and MUST NOT set the attribute bit in the result bitmap. The server		ibute value
	MUST return an error if it supports an attribute on the target		and <bcp14>MUST NOT</bcp14> set the attribute bit in the result bitmap. T
			he server
			<bcp14>MUST</bcp14> return an error if it supports an attribute on the tar
			get
	but cannot obtain its value. In that case, no attribute values will		but cannot obtain its value. In that case, no attribute values will
	be returned.		be returned.
	</t>		</t>
	<t>		<t>
	File systems that are absent should be treated as having support for		File systems that are absent should be treated as having support for
	a very small set of attributes as described in		a very small set of attributes as described in
	<xref target="absent_getattr"/>,		<xref target="absent_getattr" format="default"/>,
	even if previously, when the file system was present, more attributes		even if previously, when the file system was present, more attributes
	were supported.		were supported.
	</t>		</t>
	<t>		<t>
	All servers MUST support the REQUIRED attributes as specified in		All servers <bcp14>MUST</bcp14> support the <bcp14>REQUIRED</bcp14> attrib
	<xref target="mandatory_attributes"/>, for all file systems,		utes as specified in
			<xref target="mandatory_attributes" format="default"/>, for all file syste
			ms,
	with the exception of absent file systems.		with the exception of absent file systems.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_GETATTR_IMPLEMENTATION" title="IMPLEMENTATIO		<section toc="exclude" anchor="OP_GETATTR_IMPLEMENTATION" numbered="true
	N">		">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	Suppose there is an OPEN_DELEGATE_WRITE delegation held by another client for		Suppose there is an OPEN_DELEGATE_WRITE delegation held by another client for
	the file		the file
	in question and size and/or change are among the set of attributes being i nterrogated. The server has two choices.		in question and size and/or change are among the set of attributes being i nterrogated. The server has two choices.
	First, the server can obtain the actual		First, the server can obtain the actual
	current value of these attributes from the client holding the delegation		current value of these attributes from the client holding the delegation
	by using the CB_GETATTR callback. Second, the server, particularly when t he		by using the CB_GETATTR callback. Second, the server, particularly when t he
	delegated client is unresponsive, can recall the		delegated client is unresponsive, can recall the
	delegation in question. The GETATTR MUST NOT proceed		delegation in question. The GETATTR <bcp14>MUST NOT</bcp14> proceed
	until one of the following occurs:		until one of the following occurs:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The requested attribute values are returned in the response to		The requested attribute values are returned in the response to
	CB_GETATTR.		CB_GETATTR.
	</t>		</li>
	<t>		<li>
	The OPEN_DELEGATE_WRITE delegation is returned.		The OPEN_DELEGATE_WRITE delegation is returned.
	</t>		</li>
	<t>		<li>
	The OPEN_DELEGATE_WRITE delegation is revoked.		The OPEN_DELEGATE_WRITE delegation is revoked.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Unless one of the above happens very quickly,		Unless one of the above happens very quickly,
	one or more NFS4ERR_DELAY errors will be returned		one or more NFS4ERR_DELAY errors will be returned
	while a delegation is outstanding.		while a delegation is outstanding.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_GETFH" numbered="true" toc="default">
	$ -->		<name>Operation 10: GETFH - Get Current Filehandle</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_GETFH_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_GETFH" title="Operation 10: GETFH - Get Current Filehandle"		<sourcecode type="xdr"><![CDATA[
	>
	<section toc="exclude" anchor="OP_GETFH_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	/* CURRENT_FH: */		/* CURRENT_FH: */
	void;		void;
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_GETFH_RESULTS" numbered="true">
			<name>RESULTS</name>
	<section toc="exclude" anchor="OP_GETFH_RESULTS" title="RESULTS">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct GETFH4resok {		struct GETFH4resok {
	nfs_fh4 object;		nfs_fh4 object;
	};		};
	union GETFH4res switch (nfsstat4 status) {		union GETFH4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	GETFH4resok resok4;		GETFH4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_GETFH_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_GETFH_DESCRIPTION" title="DESCRIPTION">
	<t>
	This operation returns the current filehandle value.		This operation returns the current filehandle value.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	<t>		<t>
	As described in <xref target="COMPOUND_Sizing_Issues"/>, GETFH		As described in <xref target="COMPOUND_Sizing_Issues" format="default"/>,
	is REQUIRED or RECOMMENDED to		GETFH
			is <bcp14>REQUIRED</bcp14> or <bcp14>RECOMMENDED</bcp14> to
	immediately follow certain operations, and servers		immediately follow certain operations, and servers
	are free to reject such operations if		are free to reject such operations if
	the client fails to insert		the client fails to insert
	GETFH in the request as REQUIRED or RECOMMENDED.		GETFH in the request as <bcp14>REQUIRED</bcp14> or <bcp14>RECOMMENDED</bcp
	<xref target="open_getfh_issue"/> provides additional		14>.
	justification for why GETFH MUST follow OPEN.		<xref target="open_getfh_issue" format="default"/> provides additional
			justification for why GETFH <bcp14>MUST</bcp14> follow OPEN.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_GETFH_IMPLEMENTATION" title="IMPLEMENTATION"		<section toc="exclude" anchor="OP_GETFH_IMPLEMENTATION" numbered="true">
	>		<name>IMPLEMENTATION</name>
	<t>		<t>
	Operations that change the current filehandle like LOOKUP or CREATE do		Operations that change the current filehandle like LOOKUP or CREATE do
	not automatically return the new filehandle as a result. For		not automatically return the new filehandle as a result. For
	instance, if a client needs to look up a directory entry and obtain its		instance, if a client needs to look up a directory entry and obtain its
	filehandle, then the following request is needed.		filehandle, then the following request is needed.
	</t>		</t>
	<t>		<ul empty="true" spacing="normal">
	<list style="empty">		<li>
	<t>
	PUTFH (directory filehandle)		PUTFH (directory filehandle)
	</t>		</li>
	<t>		<li>
	LOOKUP (entry name)		LOOKUP (entry name)
	</t>		</li>
	<t>		<li>
	GETFH		GETFH
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="OP_LINK" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 11: LINK - Create Link to a File</name>
	$ -->		<section toc="exclude" anchor="OP_LINK_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The IETF Trust (2007) -->		<name>ARGUMENTS</name>
	<!-- Copyright (C) The Internet Society (2006) -->		<sourcecode type="xdr"><![CDATA[
	<section anchor="OP_LINK" title="Operation 11: LINK - Create Link to a File" >
	<section toc="exclude" anchor="OP_LINK_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct LINK4args {		struct LINK4args {
	/* SAVED_FH: source object */		/* SAVED_FH: source object */
	/* CURRENT_FH: target directory */		/* CURRENT_FH: target directory */
	component4 newname;		component4 newname;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LINK_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_LINK_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct LINK4resok {		struct LINK4resok {
	change_info4 cinfo;		change_info4 cinfo;
	};		};
	union LINK4res switch (nfsstat4 status) {		union LINK4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	LINK4resok resok4;		LINK4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LINK_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_LINK_DESCRIPTION" title="DESCRIPTION">
	<t>
	The LINK operation creates an additional newname for the file		The LINK operation creates an additional newname for the file
	represented by the saved filehandle, as set by the SAVEFH operation,		represented by the saved filehandle, as set by the SAVEFH operation,
	in the directory represented by the current filehandle. The existing		in the directory represented by the current filehandle. The existing
	file and the target directory must reside within the same file system		file and the target directory must reside within the same file system
	on the server. On success, the current filehandle will continue to be		on the server. On success, the current filehandle will continue to be
	the target directory. If an object exists in the target directory		the target directory. If an object exists in the target directory
	with the same name as newname, the server must return NFS4ERR_EXIST.		with the same name as newname, the server must return NFS4ERR_EXIST.
	</t>		</t>
	<t>		<t>
	For the target directory, the server returns change_info4 information		For the target directory, the server returns change_info4 information
	in cinfo. With the atomic field of the change_info4 data type, the		in cinfo. With the atomic field of the change_info4 data type, the
	server will indicate if the before and after change attributes were		server will indicate if the before and after change attributes were
	obtained atomically with respect to the link creation.		obtained atomically with respect to the link creation.
	</t>		</t>
	<t>		<t>
	If the newname has a length of zero, or if newname does not obey		If the newname has a length of zero, or if newname does not obey
	the UTF-8 definition, the error NFS4ERR_INVAL will be returned.		the UTF-8 definition, the error NFS4ERR_INVAL will be returned.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_LINK_IMPLEMENTATION" title="IMPLEMENTATION">		<section toc="exclude" anchor="OP_LINK_IMPLEMENTATION" numbered="true">
	<t>		<name>IMPLEMENTATION</name>
	The server MAY impose restrictions on the LINK operation such that		<t>
			The server <bcp14>MAY</bcp14> impose restrictions on the LINK operation su
			ch that
	LINK may not be done when the file is open or when that open is done		LINK may not be done when the file is open or when that open is done
	by particular protocols, or with particular options or access modes.		by particular protocols, or with particular options or access modes.
	When LINK is rejected because of such restrictions, the error		When LINK is rejected because of such restrictions, the error
	NFS4ERR_FILE_OPEN is returned.		NFS4ERR_FILE_OPEN is returned.
	</t>		</t>
	<t>		<t>
	If a server does implement such restrictions and those restrictions		If a server does implement such restrictions and those restrictions
	include cases of NFSv4 opens preventing successful execution of		include cases of NFSv4 opens preventing successful execution of
	a link, the server needs to recall any delegations that could		a link, the server needs to recall any delegations that could
	hide the existence of opens relevant to that decision. The reason		hide the existence of opens relevant to that decision. The reason
	is that when a client holds a delegation, the server		is that when a client holds a delegation, the server
	might not have an accurate account of the opens for that client, since		might not have an accurate account of the opens for that client, since
	the client may execute OPENs and CLOSEs locally. The LINK operation		the client may execute OPENs and CLOSEs locally. The LINK operation
	must be delayed only until a definitive result can be obtained.		must be delayed only until a definitive result can be obtained.
	For example, suppose there are multiple delegations and one of them establ ishes		For example, suppose there are multiple delegations and one of them establ ishes
	an open whose presence would prevent the link. Given the server's		an open whose presence would prevent the link. Given the server's
	semantics, NFS4ERR_FILE_OPEN may be returned to the caller as soon		semantics, NFS4ERR_FILE_OPEN may be returned to the caller as soon
	as that delegation is returned without waiting for other delegations		as that delegation is returned without waiting for other delegations
	to be returned. Similarly, if such opens are not associated with		to be returned. Similarly, if such opens are not associated with
	delegations, NFS4ERR_FILE_OPEN can be returned immediately with no		delegations, NFS4ERR_FILE_OPEN can be returned immediately with no
	delegation recall being done.		delegation recall being done.
	</t>		</t>
	<t>		<t>
	If the current filehandle designates a directory for which another		If the current filehandle designates a directory for which another
	client holds a directory delegation, then, unless the delegation		client holds a directory delegation, then, unless the delegation
	is such that the situation can be resolved by sending a notification,		is such that the situation can be resolved by sending a notification,
	the delegation MUST be recalled, and the operation cannot be		the delegation <bcp14>MUST</bcp14> be recalled, and the operation cannot b e
	performed successfully until the delegation is returned or revoked. Excep t where this		performed successfully until the delegation is returned or revoked. Excep t where this
	happens very quickly, one or more NFS4ERR_DELAY errors will be		happens very quickly, one or more NFS4ERR_DELAY errors will be
	returned to requests made while delegation remains outstanding.		returned to requests made while delegation remains outstanding.
	</t>		</t>
	<t>		<t>
	When the current filehandle designates a directory for which		When the current filehandle designates a directory for which
	one or more directory delegations exist, then, when those delegations		one or more directory delegations exist, then, when those delegations
	request such notifications, instead of a recall,		request such notifications, instead of a recall,
	NOTIFY4_ADD_ENTRY will be generated		NOTIFY4_ADD_ENTRY will be generated
	as a result of the LINK operation.		as a result of the LINK operation.
	</t>		</t>
	<t>		<t>
	If the current file system supports the numlinks attribute, and		If the current file system supports the numlinks attribute, and
	other clients have delegations to the file being linked, then those		other clients have delegations to the file being linked, then those
	delegations MUST be recalled and the LINK operation MUST NOT proceed until		delegations <bcp14>MUST</bcp14> be recalled and the LINK operation <bcp14> MUST NOT</bcp14> proceed until
	all delegations are returned or revoked. Except where this		all delegations are returned or revoked. Except where this
	happens very quickly, one or more NFS4ERR_DELAY errors will be		happens very quickly, one or more NFS4ERR_DELAY errors will be
	returned to requests made while delegation remains outstanding.		returned to requests made while delegation remains outstanding.
	</t>		</t>
	<t>		<t>
	Changes to any property of the "hard" linked files are reflected in		Changes to any property of the "hard" linked files are reflected in
	all of the linked files. When a link is made to a file, the		all of the linked files. When a link is made to a file, the
	attributes for the file should have a value for numlinks that is one		attributes for the file should have a value for numlinks that is one
	greater than the value before the LINK operation.		greater than the value before the LINK operation.
	</t>		</t>
	<t>		<t>
	The statement "file and the target directory must reside within the		The statement "file and the target directory must reside within the
	same file system on the server" means that the fsid fields in the		same file system on the server" means that the fsid fields in the
	attributes for the objects are the same. If they reside on		attributes for the objects are the same. If they reside on
	different file systems, the error NFS4ERR_XDEV is returned.		different file systems, the error NFS4ERR_XDEV is returned.
	This error may be returned by some servers when there is an		This error may be returned by some servers when there is an
	internal partitioning of a file system that the LINK operation		internal partitioning of a file system that the LINK operation
	would violate.		would violate.
	</t>		</t>
	<t>		<t>
	On some		On some
	servers, "." and ".." are illegal values for newname		servers, "." and ".." are illegal values for newname
	and the error NFS4ERR_BADNAME will be returned if they are specified.		and the error NFS4ERR_BADNAME will be returned if they are specified.
	</t>		</t>
	<t>		<t>
	When the current filehandle designates a named attribute directory		When the current filehandle designates a named attribute directory
	and the object to be linked (the saved filehandle) is not a named		and the object to be linked (the saved filehandle) is not a named
	attribute for the same object, the error NFS4ERR_XDEV MUST be		attribute for the same object, the error NFS4ERR_XDEV <bcp14>MUST</bcp14> be
	returned. When the saved filehandle designates a named attribute		returned. When the saved filehandle designates a named attribute
	and the current filehandle is not the appropriate named attribute		and the current filehandle is not the appropriate named attribute
	directory, the error NFS4ERR_XDEV MUST also be returned.		directory, the error NFS4ERR_XDEV <bcp14>MUST</bcp14> also be returned.
	</t>		</t>
	<t>		<t>
	When the current filehandle designates a named attribute directory		When the current filehandle designates a named attribute directory
	and the object to be linked (the saved filehandle) is a named		and the object to be linked (the saved filehandle) is a named
	attribute within that directory, the server may return		attribute within that directory, the server may return
	the error NFS4ERR_NOTSUPP.		the error NFS4ERR_NOTSUPP.
	</t>		</t>
	<t>		<t>
	In the case that newname is already linked to the file represented by		In the case that newname is already linked to the file represented by
	the saved filehandle, the server will return NFS4ERR_EXIST.		the saved filehandle, the server will return NFS4ERR_EXIST.
	</t>		</t>
	<t>		<t>
	Note that symbolic links are created with the CREATE operation.		Note that symbolic links are created with the CREATE operation.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_LOCK" numbered="true" toc="default">
	$ -->		<name>Operation 12: LOCK - Create Lock</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_LOCK_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_LOCK" title="Operation 12: LOCK - Create Lock" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_LOCK_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	/*		/*
	* For LOCK, transition from open_stateid and lock_owner		* For LOCK, transition from open_stateid and lock_owner
	* to a lock stateid.		* to a lock stateid.
	*/		*/
	struct open_to_lock_owner4 {		struct open_to_lock_owner4 {
	seqid4 open_seqid;		seqid4 open_seqid;
	stateid4 open_stateid;		stateid4 open_stateid;
	seqid4 lock_seqid;		seqid4 lock_seqid;
	lock_owner4 lock_owner;		lock_owner4 lock_owner;
	};		};
	skipping to change at line 30904 ¶		skipping to change at line 31253 ¶
	/*		/*
	* LOCK/LOCKT/LOCKU: Record lock management		* LOCK/LOCKT/LOCKU: Record lock management
	*/		*/
	struct LOCK4args {		struct LOCK4args {
	/* CURRENT_FH: file */		/* CURRENT_FH: file */
	nfs_lock_type4 locktype;		nfs_lock_type4 locktype;
	bool reclaim;		bool reclaim;
	offset4 offset;		offset4 offset;
	length4 length;		length4 length;
	locker4 locker;		locker4 locker;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LOCK_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_LOCK_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct LOCK4denied {		struct LOCK4denied {
	offset4 offset;		offset4 offset;
	length4 length;		length4 length;
	nfs_lock_type4 locktype;		nfs_lock_type4 locktype;
	lock_owner4 owner;		lock_owner4 owner;
	};		};
	struct LOCK4resok {		struct LOCK4resok {
	stateid4 lock_stateid;		stateid4 lock_stateid;
	};		};
	union LOCK4res switch (nfsstat4 status) {		union LOCK4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	LOCK4resok resok4;		LOCK4resok resok4;
	case NFS4ERR_DENIED:		case NFS4ERR_DENIED:
	LOCK4denied denied;		LOCK4denied denied;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LOCK_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_LOCK_DESCRIPTION" title="DESCRIPTION">
	<t>
	The LOCK operation requests a byte-range lock for the byte-range specified		The LOCK operation requests a byte-range lock for the byte-range specified
	by the offset and length parameters, and lock type specified in		by the offset and length parameters, and lock type specified in
	the locktype parameter. If this is a reclaim request, the		the locktype parameter. If this is a reclaim request, the
	reclaim parameter will be TRUE.		reclaim parameter will be TRUE.
	</t>		</t>
	<t>		<t>
	Bytes in a file may be locked even if those bytes are not currently		Bytes in a file may be locked even if those bytes are not currently
	allocated to the file. To lock the file from a specific offset		allocated to the file. To lock the file from a specific offset
	through the end-of-file (no matter how long the file actually is) use		through the end-of-file (no matter how long the file actually is) use
	a length field equal to NFS4_UINT64_MAX.		a length field equal to NFS4_UINT64_MAX.
	The server MUST return NFS4ERR_INVAL under the following		The server <bcp14>MUST</bcp14> return NFS4ERR_INVAL under the following
	combinations of length and offset:		combinations of length and offset:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	Length is equal to zero.		Length is equal to zero.
	</t>		</li>
	<t>		<li>
	Length is not equal to NFS4_UINT64_MAX, and the sum of length		Length is not equal to NFS4_UINT64_MAX, and the sum of length
	and offset exceeds NFS4_UINT64_MAX.		and offset exceeds NFS4_UINT64_MAX.
	</t>		</li>
	</list>		</ul>
			<t>
	</t>
	<t>
	32-bit servers are servers that support locking for		32-bit servers are servers that support locking for
	byte offsets that fit within 32 bits (i.e., less than		byte offsets that fit within 32 bits (i.e., less than
	or equal to NFS4_UINT32_MAX). If the client specifies a		or equal to NFS4_UINT32_MAX). If the client specifies a
	range that overlaps one or more bytes beyond offset		range that overlaps one or more bytes beyond offset
	NFS4_UINT32_MAX but does not end at offset		NFS4_UINT32_MAX but does not end at offset
	NFS4_UINT64_MAX, then such a 32-bit server MUST return the		NFS4_UINT64_MAX, then such a 32-bit server <bcp14>MUST</bcp14> return the
	error NFS4ERR_BAD_RANGE.		error NFS4ERR_BAD_RANGE.
	</t>		</t>
	<t>		<t>
	If the server returns NFS4ERR_DENIED, the		If the server returns NFS4ERR_DENIED, the
	owner, offset, and length		owner, offset, and length
	of a conflicting lock are returned.		of a conflicting lock are returned.
	</t>		</t>
	<t>		<t>
	The locker argument specifies the lock-owner that is associated with		The locker argument specifies the lock-owner that is associated with
	the LOCK operation. The locker4 structure is a switched union that		the LOCK operation. The locker4 structure is a switched union that
	indicates whether the client has already created byte-range locking		indicates whether the client has already created byte-range locking
	state associated with the current open file and lock-owner. In the		state associated with the current open file and lock-owner. In the
	case in which it has, the argument is just a stateid representing		case in which it has, the argument is just a stateid representing
	the set of		the set of
	locks associated with that open file and lock-owner, together with		locks associated with that open file and lock-owner, together with
	a lock_seqid value that MAY be any value and MUST be ignored		a lock_seqid value that <bcp14>MAY</bcp14> be any value and <bcp14>MUST</b cp14> be ignored
	by the server.		by the server.
	In the case where no byte-range locking state has been established, or the client		In the case where no byte-range locking state has been established, or the client
	does not have the stateid available, the argument contains the		does not have the stateid available, the argument contains the
	stateid of the open file with which this lock is to be associated,		stateid of the open file with which this lock is to be associated,
	together with the lock-owner with which the lock is to be associated.		together with the lock-owner with which the lock is to be associated.
	The open_to_lock_owner case covers the very first lock done by a		The open_to_lock_owner case covers the very first lock done by a
	lock-owner for a given open file and offers a method to use the		lock-owner for a given open file and offers a method to use the
	established state of the open_stateid to transition to the use of		established state of the open_stateid to transition to the use of
	a lock stateid.		a lock stateid.
	</t>		</t>
	<t>		<t>
	The following fields of the locker parameter MAY be		The following fields of the locker parameter <bcp14>MAY</bcp14> be
	set to any value by the client and MUST be ignored		set to any value by the client and <bcp14>MUST</bcp14> be ignored
	by the server:		by the server:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	The clientid field of the lock_owner		The clientid field of the lock_owner
	field of the open_owner field		field of the open_owner field
	(locker.open_owner.lock_owner.clientid). The		(locker.open_owner.lock_owner.clientid). The
	reason the server MUST ignore the clientid field		reason the server <bcp14>MUST</bcp14> ignore the clientid field
	is that the server MUST derive the client ID from		is that the server <bcp14>MUST</bcp14> derive the client ID from
	the session ID from the SEQUENCE operation of the		the session ID from the SEQUENCE operation of the
	COMPOUND request.		COMPOUND request.
	</t>		</li>
	<t>		<li>
	The open_seqid and lock_seqid fields of the		The open_seqid and lock_seqid fields of the
	open_owner field (locker.open_owner.open_seqid and		open_owner field (locker.open_owner.open_seqid and
	locker.open_owner.lock_seqid).		locker.open_owner.lock_seqid).
	</t>		</li>
	<t>		<li>
	The lock_seqid field of the lock_owner field		The lock_seqid field of the lock_owner field
	(locker.lock_owner.lock_seqid).		(locker.lock_owner.lock_seqid).
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Note that the client ID appearing in a LOCK4denied		Note that the client ID appearing in a LOCK4denied
	structure is the actual client associated with the		structure is the actual client associated with the
	conflicting lock, whether this is the client ID		conflicting lock, whether this is the client ID
	associated with the current session or a different		associated with the current session or a different
	one. Thus, if the server returns NFS4ERR_DENIED,		one. Thus, if the server returns NFS4ERR_DENIED,
	it MUST set the clientid field of the owner field of the		it <bcp14>MUST</bcp14> set the clientid field of the owner field of the
	denied field.		denied field.
	</t>		</t>
			<t>
	<t>
	If the current filehandle is not an ordinary file, an error will be		If the current filehandle is not an ordinary file, an error will be
	returned to the client. In the case that the current filehandle		returned to the client. In the case that the current filehandle
	represents an object of type NF4DIR, NFS4ERR_ISDIR is returned.		represents an object of type NF4DIR, NFS4ERR_ISDIR is returned.
	If the current filehandle designates a symbolic link,		If the current filehandle designates a symbolic link,
	NFS4ERR_SYMLINK is returned. In all other cases,		NFS4ERR_SYMLINK is returned. In all other cases,
	NFS4ERR_WRONG_TYPE is returned.		NFS4ERR_WRONG_TYPE is returned.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_LOCK_IMPLEMENTATION" title="IMPLEMENTATION">		<section toc="exclude" anchor="OP_LOCK_IMPLEMENTATION" numbered="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	If the server is unable to determine the exact offset and length of		If the server is unable to determine the exact offset and length of
	the conflicting byte-range lock, the same offset and length that were prov ided in		the conflicting byte-range lock, the same offset and length that were prov ided in
	the arguments should be returned in the denied results.		the arguments should be returned in the denied results.
	</t>		</t>
	<t>		<t>
	LOCK operations are subject to permission checks and to checks against		LOCK operations are subject to permission checks and to checks against
	the access type of the associated file. However, the specific right		the access type of the associated file. However, the specific right
	and modes required for various types of locks reflect the semantics of		and modes required for various types of locks reflect the semantics of
	the server-exported file system, and are not specified by the protocol.		the server-exported file system, and are not specified by the protocol.
	For example, Windows 2000 allows a write lock of a file open for read acce ss,		For example, Windows 2000 allows a write lock of a file open for read acce ss,
	while a POSIX-compliant system does not.		while a POSIX-compliant system does not.
	</t>		</t>
	<t>		<t>
	When the client sends a LOCK operation that corresponds to a range that		When the client sends a LOCK operation that corresponds to a range that
	the lock-owner has locked already (with the same or different lock		the lock-owner has locked already (with the same or different lock
	type), or to a sub-range of such a range, or to a byte-range that		type), or to a sub-range of such a range, or to a byte-range that
	includes multiple locks already granted to that lock-owner, in whole or		includes multiple locks already granted to that lock-owner, in whole or
	in part, and the server does not support such locking operations		in part, and the server does not support such locking operations
	(i.e., does not support POSIX locking semantics), the server will		(i.e., does not support POSIX locking semantics), the server will
	return the error NFS4ERR_LOCK_RANGE. In that case, the client may		return the error NFS4ERR_LOCK_RANGE. In that case, the client may
	return an error, or it may emulate the required operations, using only		return an error, or it may emulate the required operations, using only
	LOCK for ranges that do not include any bytes already locked by that		LOCK for ranges that do not include any bytes already locked by that
	lock-owner and LOCKU of locks held by that lock-owner (specifying an		lock-owner and LOCKU of locks held by that lock-owner (specifying an
	exactly matching range and type). Similarly, when the client sends a		exactly matching range and type). Similarly, when the client sends a
	LOCK operation that amounts to upgrading (changing from a READ_LT lock to a		LOCK operation that amounts to upgrading (changing from a READ_LT lock to a
	WRITE_LT lock) or downgrading (changing from WRITE_LT lock to a READ_LT lo ck)		WRITE_LT lock) or downgrading (changing from WRITE_LT lock to a READ_LT lo ck)
	an existing byte-range lock, and the server does not support such a lock,		an existing byte-range lock, and the server does not support such a lock,
	the server will return NFS4ERR_LOCK_NOTSUPP. Such operations may not		the server will return NFS4ERR_LOCK_NOTSUPP. Such operations may not
	perfectly reflect the required semantics in the face of conflicting		perfectly reflect the required semantics in the face of conflicting
	LOCK operations from other clients.		LOCK operations from other clients.
	</t>		</t>
	<t>		<t>
	When a client holds an OPEN_DELEGATE_WRITE delegation, the client holding that		When a client holds an OPEN_DELEGATE_WRITE delegation, the client holding that
	delegation is assured that there are no opens by other clients.		delegation is assured that there are no opens by other clients.
	Thus, there can be no conflicting LOCK operations from such clients.		Thus, there can be no conflicting LOCK operations from such clients.
	Therefore, the client may be handling locking requests locally,		Therefore, the client may be handling locking requests locally,
	without		without
	doing LOCK operations on the server. If it does that, it must be		doing LOCK operations on the server. If it does that, it must be
	prepared to update the lock status on the server, by sending		prepared to update the lock status on the server, by sending
	appropriate LOCK and LOCKU operations before returning		appropriate LOCK and LOCKU operations before returning
	the delegation.		the delegation.
	</t>		</t>
	<t>		<t>
	When one or more clients hold OPEN_DELEGATE_READ delegations, any LOCK ope ration		When one or more clients hold OPEN_DELEGATE_READ delegations, any LOCK ope ration
	where the server is implementing mandatory locking semantics MUST		where the server is implementing mandatory locking semantics <bcp14>MUST</ bcp14>
	result in the recall of all such delegations. The LOCK operation may		result in the recall of all such delegations. The LOCK operation may
	not be granted until all such delegations are returned or revoked.		not be granted until all such delegations are returned or revoked.
	Except where this		Except where this
	happens very quickly, one or more NFS4ERR_DELAY errors will be		happens very quickly, one or more NFS4ERR_DELAY errors will be
	returned to requests made while the delegation remains outstanding.		returned to requests made while the delegation remains outstanding.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_LOCKT" numbered="true" toc="default">
	$ -->		<name>Operation 13: LOCKT - Test for Lock</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_LOCKT_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_LOCKT" title="Operation 13: LOCKT - Test for Lock" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_LOCKT_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct LOCKT4args {		struct LOCKT4args {
	/* CURRENT_FH: file */		/* CURRENT_FH: file */
	nfs_lock_type4 locktype;		nfs_lock_type4 locktype;
	offset4 offset;		offset4 offset;
	length4 length;		length4 length;
	lock_owner4 owner;		lock_owner4 owner;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LOCKT_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_LOCKT_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	union LOCKT4res switch (nfsstat4 status) {		union LOCKT4res switch (nfsstat4 status) {
	case NFS4ERR_DENIED:		case NFS4ERR_DENIED:
	LOCK4denied denied;		LOCK4denied denied;
	case NFS4_OK:		case NFS4_OK:
	void;		void;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LOCKT_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_LOCKT_DESCRIPTION" title="DESCRIPTION">
	<t>
	The LOCKT operation tests the lock as specified in the arguments. If		The LOCKT operation tests the lock as specified in the arguments. If
	a conflicting lock exists, the owner, offset, length, and type of the		a conflicting lock exists, the owner, offset, length, and type of the
	conflicting lock are returned.		conflicting lock are returned.
	The owner field in the results includes the client ID of the owner of		The owner field in the results includes the client ID of the owner of
	the conflicting lock, whether this is the client ID associated with the		the conflicting lock, whether this is the client ID associated with the
	current session or a different client ID.		current session or a different client ID.
	If no lock is held, nothing other than		If no lock is held, nothing other than
	NFS4_OK is returned. Lock types READ_LT and READW_LT are processed in		NFS4_OK is returned. Lock types READ_LT and READW_LT are processed in
	the same way in that a conflicting lock test is done without regard to		the same way in that a conflicting lock test is done without regard to
	blocking or non-blocking. The same is true for WRITE_LT and WRITEW_LT.		blocking or non-blocking. The same is true for WRITE_LT and WRITEW_LT.
	</t>		</t>
	<t>		<t>
	The ranges are specified as for LOCK. The NFS4ERR_INVAL and		The ranges are specified as for LOCK. The NFS4ERR_INVAL and
	NFS4ERR_BAD_RANGE errors are returned under the same circumstances		NFS4ERR_BAD_RANGE errors are returned under the same circumstances
	as for LOCK.		as for LOCK.
	</t>		</t>
	<t>		<t>
	The clientid field of the owner MAY be set to		The clientid field of the owner <bcp14>MAY</bcp14> be set to
	any value by the client and MUST be ignored by		any value by the client and <bcp14>MUST</bcp14> be ignored by
	the server. The reason the server MUST ignore the		the server. The reason the server <bcp14>MUST</bcp14> ignore the
	clientid field is that the server MUST derive the		clientid field is that the server <bcp14>MUST</bcp14> derive the
	client ID from the session ID from the SEQUENCE		client ID from the session ID from the SEQUENCE
	operation of the COMPOUND request.		operation of the COMPOUND request.
	</t>		</t>
	<t>		<t>
	If the current filehandle is not an ordinary file, an error will be		If the current filehandle is not an ordinary file, an error will be
	returned to the client. In the case that the current filehandle		returned to the client. In the case that the current filehandle
	represents an object of type NF4DIR, NFS4ERR_ISDIR is returned.		represents an object of type NF4DIR, NFS4ERR_ISDIR is returned.
	If the current filehandle designates a symbolic link,		If the current filehandle designates a symbolic link,
	NFS4ERR_SYMLINK is returned. In all other cases,		NFS4ERR_SYMLINK is returned. In all other cases,
	NFS4ERR_WRONG_TYPE is returned.		NFS4ERR_WRONG_TYPE is returned.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_LOCKT_IMPLEMENTATION" title="IMPLEMENTATION"		<section toc="exclude" anchor="OP_LOCKT_IMPLEMENTATION" numbered="true">
	>		<name>IMPLEMENTATION</name>
	<t>		<t>
	If the server is unable to determine the exact offset		If the server is unable to determine the exact offset
	and length of the conflicting lock, the same offset		and length of the conflicting lock, the same offset
	and length that were provided in the arguments should		and length that were provided in the arguments should
	be returned in the denied results.		be returned in the denied results.
	</t>		</t>
			<t>
	<t>
	LOCKT uses a lock_owner4 rather a stateid4, as is used in		LOCKT uses a lock_owner4 rather a stateid4, as is used in
	LOCK to identify the owner. This is because the client does not		LOCK to identify the owner. This is because the client does not
	have to open the file to test for the existence of a lock, so		have to open the file to test for the existence of a lock, so
	a stateid might not be available.		a stateid might not be available.
	</t>		</t>
	<t>		<t>
	As noted in <xref target="OP_LOCK_IMPLEMENTATION"/>, some		As noted in <xref target="OP_LOCK_IMPLEMENTATION" format="default"/>, some
	servers may return NFS4ERR_LOCK_RANGE to certain (otherwise		servers may return NFS4ERR_LOCK_RANGE to certain (otherwise
	non-conflicting) LOCK operations that overlap ranges already		non-conflicting) LOCK operations that overlap ranges already
	granted to the current lock-owner.		granted to the current lock-owner.
	</t>		</t>
			<t>
	<t>		The LOCKT operation's test for conflicting locks <bcp14>SHOULD</bcp14> exc
	The LOCKT operation's test for conflicting locks SHOULD exclude		lude
	locks for the current lock-owner, and thus should return NFS4_OK in		locks for the current lock-owner, and thus should return NFS4_OK in
	such cases. Note that this means that a server might return		such cases. Note that this means that a server might return
	NFS4_OK to a LOCKT request even though a LOCK operation for the		NFS4_OK to a LOCKT request even though a LOCK operation for the
	same range and lock-owner would fail with NFS4ERR_LOCK_RANGE.		same range and lock-owner would fail with NFS4ERR_LOCK_RANGE.
	</t>		</t>
			<t>
	<t>
	When a client holds an OPEN_DELEGATE_WRITE delegation, it may choose		When a client holds an OPEN_DELEGATE_WRITE delegation, it may choose
	(see <xref target="OP_LOCK_IMPLEMENTATION" />) to handle LOCK		(see <xref target="OP_LOCK_IMPLEMENTATION" format="default"/>) to handle L OCK
	requests locally. In such a case, LOCKT requests will similarly		requests locally. In such a case, LOCKT requests will similarly
	be handled locally.		be handled locally.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_LOCKU" numbered="true" toc="default">
	$ -->		<name>Operation 14: LOCKU - Unlock File</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_LOCKU_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_LOCKU" title="Operation 14: LOCKU - Unlock File" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_LOCKU_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct LOCKU4args {		struct LOCKU4args {
	/* CURRENT_FH: file */		/* CURRENT_FH: file */
	nfs_lock_type4 locktype;		nfs_lock_type4 locktype;
	seqid4 seqid;		seqid4 seqid;
	stateid4 lock_stateid;		stateid4 lock_stateid;
	offset4 offset;		offset4 offset;
	length4 length;		length4 length;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LOCKU_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_LOCKU_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	union LOCKU4res switch (nfsstat4 status) {		union LOCKU4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	stateid4 lock_stateid;		stateid4 lock_stateid;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LOCKU_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_LOCKU_DESCRIPTION" title="DESCRIPTION">
	<t>
	The LOCKU operation unlocks the byte-range lock specified by the		The LOCKU operation unlocks the byte-range lock specified by the
	parameters. The client may set the locktype field to any value that is		parameters. The client may set the locktype field to any value that is
	legal for the nfs_lock_type4 enumerated type, and the server MUST		legal for the nfs_lock_type4 enumerated type, and the server <bcp14>MUST</ bcp14>
	accept any legal value for locktype. Any legal value for locktype has		accept any legal value for locktype. Any legal value for locktype has
	no effect on the success or failure of the LOCKU operation.		no effect on the success or failure of the LOCKU operation.
	</t>		</t>
	<t>		<t>
	The ranges are specified as for LOCK. The NFS4ERR_INVAL and		The ranges are specified as for LOCK. The NFS4ERR_INVAL and
	NFS4ERR_BAD_RANGE errors are returned under the same circumstances as		NFS4ERR_BAD_RANGE errors are returned under the same circumstances as
	for LOCK.		for LOCK.
	</t>		</t>
	<t>		<t>
	The seqid parameter MAY be any value and the server MUST ignore it.		The seqid parameter <bcp14>MAY</bcp14> be any value and the server <bcp14>
	</t>		MUST</bcp14> ignore it.
	<t>		</t>
			<t>
	If the current filehandle is not an ordinary file, an error will be		If the current filehandle is not an ordinary file, an error will be
	returned to the client. In the case that the current filehandle		returned to the client. In the case that the current filehandle
	represents an object of type NF4DIR, NFS4ERR_ISDIR is returned.		represents an object of type NF4DIR, NFS4ERR_ISDIR is returned.
	If the current filehandle designates a symbolic link,		If the current filehandle designates a symbolic link,
	NFS4ERR_SYMLINK is returned. In all other cases,		NFS4ERR_SYMLINK is returned. In all other cases,
	NFS4ERR_WRONG_TYPE is returned.		NFS4ERR_WRONG_TYPE is returned.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	<t>		<t>
	The server MAY require that the principal, security		The server <bcp14>MAY</bcp14> require that the principal, security
	flavor, and if applicable, the GSS mechanism, combination		flavor, and if applicable, the GSS mechanism, combination
	that sent a LOCK operation also be the one to send		that sent a LOCK operation also be the one to send
	LOCKU on the file. This might not be possible		LOCKU on the file. This might not be possible
	if credentials for the principal are no longer		if credentials for the principal are no longer
	available. The server MAY allow the machine credential		available. The server <bcp14>MAY</bcp14> allow the machine credential
	or SSV credential (see <xref target="OP_EXCHANGE_ID"		or SSV credential (see <xref target="OP_EXCHANGE_ID" format="default"/>) to
	/>) to send LOCKU.		send LOCKU.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_LOCKU_IMPLEMENTATION" title="IMPLEMENTATION"		<section toc="exclude" anchor="OP_LOCKU_IMPLEMENTATION" numbered="true">
	>		<name>IMPLEMENTATION</name>
	<t>		<t>
	If the area to be unlocked does not correspond exactly to a lock		If the area to be unlocked does not correspond exactly to a lock
	actually held by the lock-owner, the server may return the error		actually held by the lock-owner, the server may return the error
	NFS4ERR_LOCK_RANGE. This includes the case in which the area is not		NFS4ERR_LOCK_RANGE. This includes the case in which the area is not
	locked, where the area is a sub-range of the area locked, where it		locked, where the area is a sub-range of the area locked, where it
	overlaps the area locked without matching exactly, or the area		overlaps the area locked without matching exactly, or the area
	specified includes multiple locks held by the lock-owner. In all of		specified includes multiple locks held by the lock-owner. In all of
	these cases, allowed by <xref target="fcntl">POSIX locking</xref> semantic s, a client receiving		these cases, allowed by <xref target="fcntl" format="default">POSIX lockin g</xref> semantics, a client receiving
	this error should, if it desires support for such operations, simulate		this error should, if it desires support for such operations, simulate
	the operation using LOCKU on ranges corresponding to locks it actually		the operation using LOCKU on ranges corresponding to locks it actually
	holds, possibly followed by LOCK operations for the sub-ranges not being		holds, possibly followed by LOCK operations for the sub-ranges not being
	unlocked.		unlocked.
	</t>		</t>
	<t>		<t>
	When a client holds an OPEN_DELEGATE_WRITE delegation, it may choose		When a client holds an OPEN_DELEGATE_WRITE delegation, it may choose
	(see <xref target="OP_LOCK_IMPLEMENTATION" />) to handle LOCK		(see <xref target="OP_LOCK_IMPLEMENTATION" format="default"/>) to handle L OCK
	requests locally. In such a case, LOCKU operations will similarly		requests locally. In such a case, LOCKU operations will similarly
	be handled locally.		be handled locally.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		<section anchor="OP_LOOKUP" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 15: LOOKUP - Lookup Filename</name>
	$ -->		<section toc="exclude" anchor="OP_LOOKUP_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The IETF Trust (2007) -->		<name>ARGUMENTS</name>
	<!-- Copyright (C) The Internet Society (2006) -->		<sourcecode type="xdr"><![CDATA[
	<section anchor="OP_LOOKUP" title="Operation 15: LOOKUP - Lookup Filename" >
	<section toc="exclude" anchor="OP_LOOKUP_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct LOOKUP4args {		struct LOOKUP4args {
	/* CURRENT_FH: directory */		/* CURRENT_FH: directory */
	component4 objname;		component4 objname;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LOOKUP_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_LOOKUP_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct LOOKUP4res {		struct LOOKUP4res {
	/* New CURRENT_FH: object */		/* New CURRENT_FH: object */
	nfsstat4 status;		nfsstat4 status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LOOKUP_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_LOOKUP_DESCRIPTION" title="DESCRIPTION">
	<t>
	The LOOKUP operation looks up or finds a file system object using the		The LOOKUP operation looks up or finds a file system object using the
	directory specified by the current filehandle. LOOKUP evaluates the		directory specified by the current filehandle. LOOKUP evaluates the
	component and if the object exists, the current filehandle is replaced		component and if the object exists, the current filehandle is replaced
	with the component's filehandle.		with the component's filehandle.
	</t>		</t>
	<t>		<t>
	If the component cannot be evaluated either because it does not exist		If the component cannot be evaluated either because it does not exist
	or because the client does not have permission to evaluate the		or because the client does not have permission to evaluate the
	component, then an error will be returned and the current filehandle		component, then an error will be returned and the current filehandle
	will be unchanged.		will be unchanged.
	</t>		</t>
	<t>		<t>
	If the component is a zero-length string or if any component does not		If the component is a zero-length string or if any component does not
	obey the UTF-8 definition, the error NFS4ERR_INVAL will be returned.		obey the UTF-8 definition, the error NFS4ERR_INVAL will be returned.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_LOOKUP_IMPLEMENTATION" title="IMPLEMENTATION		<section toc="exclude" anchor="OP_LOOKUP_IMPLEMENTATION" numbered="true"
	">		>
	<t>		<name>IMPLEMENTATION</name>
			<t>
	If the client wants to achieve the effect of a multi-component look up,		If the client wants to achieve the effect of a multi-component look up,
	it may construct a COMPOUND request such as (and obtain each		it may construct a COMPOUND request such as (and obtain each
	filehandle):		filehandle):
	<figure>		</t>
	<artwork>		<sourcecode type="nfsv4compound"><![CDATA[
	PUTFH (directory filehandle)		PUTFH (directory filehandle)
	LOOKUP "pub"		LOOKUP "pub"
	GETFH		GETFH
	LOOKUP "foo"		LOOKUP "foo"
	GETFH		GETFH
	LOOKUP "bar"		LOOKUP "bar"
	GETFH		GETFH]]></sourcecode>
	</artwork>		<t>
	</figure>
	Unlike NFSv3, NFSv4.1 allows LOOKUP requests to cross mountpoints on the		Unlike NFSv3, NFSv4.1 allows LOOKUP requests to cross mountpoints on the
	server. The client can detect a mountpoint crossing by comparing the		server. The client can detect a mountpoint crossing by comparing the
	fsid attribute of the directory with the fsid attribute of the		fsid attribute of the directory with the fsid attribute of the
	directory looked up. If the fsids are different, then the new		directory looked up. If the fsids are different, then the new
	directory is a server mountpoint. UNIX clients that detect a		directory is a server mountpoint. UNIX clients that detect a
	mountpoint crossing will need to mount the server's file system. This		mountpoint crossing will need to mount the server's file system. This
	needs to be done to maintain the file object identity checking		needs to be done to maintain the file object identity checking
	mechanisms common to UNIX clients.		mechanisms common to UNIX clients.
	</t>		</t>
	<t>		<t>
	Servers that limit NFS access to "shared" or "exported" file systems		Servers that limit NFS access to "shared" or "exported" file systems
	should provide a pseudo file system into which the exported file systems		should provide a pseudo file system into which the exported file systems
	can be integrated, so that clients can browse the server's namespace.		can be integrated, so that clients can browse the server's namespace.
	The clients view of a pseudo file system will be limited to paths that		The clients view of a pseudo file system will be limited to paths that
	lead to exported file systems.		lead to exported file systems.
	</t>		</t>
	<t>		<t>
	Note: previous versions of the protocol assigned special semantics to		Note: previous versions of the protocol assigned special semantics to
	the names "." and "..". NFSv4.1 assigns no special semantics to		the names "." and "..". NFSv4.1 assigns no special semantics to
	these names. The LOOKUPP operator must be used to look up a parent		these names. The LOOKUPP operator must be used to look up a parent
	directory.		directory.
	</t>		</t>
	<t>		<t>
	Note that this operation does not follow symbolic links. The client		Note that this operation does not follow symbolic links. The client
	is responsible for all parsing of filenames including filenames that		is responsible for all parsing of filenames including filenames that
	are modified by symbolic links encountered during the look up process.		are modified by symbolic links encountered during the look up process.
	</t>		</t>
	<t>		<t>
	If the current filehandle supplied is not a directory but a symbolic		If the current filehandle supplied is not a directory but a symbolic
	link, the error NFS4ERR_SYMLINK is returned as the error. For all		link, the error NFS4ERR_SYMLINK is returned as the error. For all
	other non-directory file types, the error NFS4ERR_NOTDIR is returned.		other non-directory file types, the error NFS4ERR_NOTDIR is returned.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_LOOKUPP" numbered="true" toc="default">
	$ -->		<name>Operation 16: LOOKUPP - Lookup Parent Directory</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_LOOKUPP_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_LOOKUPP" title="Operation 16: LOOKUPP - Lookup Parent Direct		<sourcecode type="xdr"><![CDATA[
	ory" >
	<section toc="exclude" anchor="OP_LOOKUPP_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	/* CURRENT_FH: object */		/* CURRENT_FH: object */
	void;		void;]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_LOOKUPP_RESULTS" numbered="true">
	</section>		<name>RESULTS</name>
			<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_LOOKUPP_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct LOOKUPP4res {		struct LOOKUPP4res {
	/* new CURRENT_FH: parent directory */		/* new CURRENT_FH: parent directory */
	nfsstat4 status;		nfsstat4 status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LOOKUPP_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_LOOKUPP_DESCRIPTION" title="DESCRIPTION">
	<t>
	The current filehandle is assumed to refer to a regular		The current filehandle is assumed to refer to a regular
	directory or a named attribute directory. LOOKUPP assigns the		directory or a named attribute directory. LOOKUPP assigns the
	filehandle for its parent directory to be the current		filehandle for its parent directory to be the current
	filehandle. If there is no parent directory, an NFS4ERR_NOENT		filehandle. If there is no parent directory, an NFS4ERR_NOENT
	error must be returned. Therefore, NFS4ERR_NOENT will be		error must be returned. Therefore, NFS4ERR_NOENT will be
	returned by the server when the current filehandle is at the		returned by the server when the current filehandle is at the
	root or top of the server's file tree.		root or top of the server's file tree.
	</t>		</t>
	<t>		<t>
	As is the case with LOOKUP, LOOKUPP will also cross mountpoints.		As is the case with LOOKUP, LOOKUPP will also cross mountpoints.
	</t>		</t>
	<t>		<t>
	If the current filehandle is not a directory or named attribute		If the current filehandle is not a directory or named attribute
	directory, the error NFS4ERR_NOTDIR is returned.		directory, the error NFS4ERR_NOTDIR is returned.
	</t>		</t>
	<t>		<t>
	If the requester's security flavor does not match that		If the requester's security flavor does not match that
	configured for the parent directory, then the server SHOULD		configured for the parent directory, then the server <bcp14>SHOULD</bcp14>
	return NFS4ERR_WRONGSEC (a future minor revision of NFSv4 may		return NFS4ERR_WRONGSEC (a future minor revision of NFSv4 may
	upgrade this to MUST) in the LOOKUPP response. However, if the		upgrade this to <bcp14>MUST</bcp14>) in the LOOKUPP response. However, if
	server does so, it MUST support the SECINFO_NO_NAME		the
	operation (<xref target="OP_SECINFO_NO_NAME"/>), so that the client can gr		server does so, it <bcp14>MUST</bcp14> support the SECINFO_NO_NAME
	acefully determine the		operation (<xref target="OP_SECINFO_NO_NAME" format="default"/>), so that
			the client can gracefully determine the
	correct security flavor.		correct security flavor.
	</t>		</t>
	<t>		<t>
	If the current filehandle is a named attribute directory that is		If the current filehandle is a named attribute directory that is
	associated with a file system object via OPENATTR (i.e., not a		associated with a file system object via OPENATTR (i.e., not a
	sub-directory of a named attribute directory), LOOKUPP SHOULD		sub-directory of a named attribute directory), LOOKUPP <bcp14>SHOULD</bcp1 4>
	return the filehandle of the associated file system object.		return the filehandle of the associated file system object.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_LOOKUPP_IMPLEMENTATION" title="IMPLEMENTATIO		<section toc="exclude" anchor="OP_LOOKUPP_IMPLEMENTATION" numbered="true
	N">		">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	An issue to note is upward navigation from named attribute		An issue to note is upward navigation from named attribute
	directories. The named attribute directories are essentially		directories. The named attribute directories are essentially
	detached from the namespace, and this property should be safely		detached from the namespace, and this property should be safely
	represented in the client operating environment. LOOKUPP on a		represented in the client operating environment. LOOKUPP on a
	named attribute directory may return the filehandle of the		named attribute directory may return the filehandle of the
	associated file, and conveying this to applications might be		associated file, and conveying this to applications might be
	unsafe as many applications expect the parent of an object to		unsafe as many applications expect the parent of an object to
	always be a directory. Therefore, the client may want to hide		always be a directory. Therefore, the client may want to hide
	the parent of named attribute directories (represented as ".."		the parent of named attribute directories (represented as ".."
	in UNIX) or represent the named attribute directory as its own		in UNIX) or represent the named attribute directory as its own
	parent (as is typically done for the file system root directory in		parent (as is typically done for the file system root directory in
	UNIX).		UNIX).
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_NVERIFY" numbered="true" toc="default">
	$ -->		<name>Operation 17: NVERIFY - Verify Difference in Attributes</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_NVERIFY_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_NVERIFY" title="Operation 17: NVERIFY - Verify Difference in		<sourcecode type="xdr"><![CDATA[
	Attributes" >
	<section toc="exclude" anchor="OP_NVERIFY_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct NVERIFY4args {		struct NVERIFY4args {
	/* CURRENT_FH: object */		/* CURRENT_FH: object */
	fattr4 obj_attributes;		fattr4 obj_attributes;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_NVERIFY_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_NVERIFY_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct NVERIFY4res {		struct NVERIFY4res {
	nfsstat4 status;		nfsstat4 status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_NVERIFY_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_NVERIFY_DESCRIPTION" title="DESCRIPTION">
	<t>
	This operation is used to prefix a sequence of operations to be		This operation is used to prefix a sequence of operations to be
	performed if one or more attributes have changed on some file system		performed if one or more attributes have changed on some file system
	object. If all the attributes match, then the error NFS4ERR_SAME MUST		object. If all the attributes match, then the error NFS4ERR_SAME <bcp14>M UST</bcp14>
	be returned.		be returned.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_NVERIFY_IMPLEMENTATION" title="IMPLEMENTATIO		<section toc="exclude" anchor="OP_NVERIFY_IMPLEMENTATION" numbered="true
	N">		">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	This operation is useful as a cache validation operator. If the		This operation is useful as a cache validation operator. If the
	object to which the attributes belong has changed, then the following		object to which the attributes belong has changed, then the following
	operations may obtain new data associated with that object, for		operations may obtain new data associated with that object, for
	instance, to check if a file has been changed and obtain new data if		instance, to check if a file has been changed and obtain new data if
	it has:		it has:
	<figure>		</t>
	<artwork>		<sourcecode type="nfsv4compound"><![CDATA[
	SEQUENCE		SEQUENCE
	PUTFH fh		PUTFH fh
	NVERIFY attrbits attrs		NVERIFY attrbits attrs
	READ 0 32767		READ 0 32767]]></sourcecode>
	</artwork>		<t>
	</figure>
	Contrast this with NFSv3, which would first send a GETATTR in		Contrast this with NFSv3, which would first send a GETATTR in
	one request/reply round trip, and then if attributes indicated that		one request/reply round trip, and then if attributes indicated that
	the client's cache was stale, then send a READ in another request/reply		the client's cache was stale, then send a READ in another request/reply
	round trip.		round trip.
	</t>		</t>
	<t>		<t>
	In the case that a RECOMMENDED attribute is specified in the NVERIFY		In the case that a <bcp14>RECOMMENDED</bcp14> attribute is specified in th
			e NVERIFY
	operation and the server does not support that attribute for the		operation and the server does not support that attribute for the
	file system object, the error NFS4ERR_ATTRNOTSUPP is returned to the		file system object, the error NFS4ERR_ATTRNOTSUPP is returned to the
	client.		client.
	</t>		</t>
	<t>		<t>
	When the attribute rdattr_error or any set-only attribute (e.g.,		When the attribute rdattr_error or any set-only attribute (e.g.,
	time_modify_set) is specified, the error NFS4ERR_INVAL is returned to		time_modify_set) is specified, the error NFS4ERR_INVAL is returned to
	the client.		the client.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->
	<!-- Copyright (C) The IETF Trust (2007-2008) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="OP_OPEN" title="Operation 18: OPEN - Open a Regular File" >
	<section toc="exclude" anchor="OP_OPEN_ARGUMENTS" title="ARGUMENTS">		<section anchor="OP_OPEN" numbered="true" toc="default">
	<figure>		<name>Operation 18: OPEN - Open a Regular File</name>
	<artwork>		<section toc="exclude" anchor="OP_OPEN_ARGUMENTS" numbered="true">
			<name>ARGUMENTS</name>
			<sourcecode type="xdr"><![CDATA[
	/*		/*
	* Various definitions for OPEN		* Various definitions for OPEN
	*/		*/
	enum createmode4 {		enum createmode4 {
	UNCHECKED4 = 0,		UNCHECKED4 = 0,
	GUARDED4 = 1,		GUARDED4 = 1,
	/* Deprecated in NFSv4.1. */		/* Deprecated in NFSv4.1. */
	EXCLUSIVE4 = 2,		EXCLUSIVE4 = 2,
	/*		/*
	* New to NFSv4.1. If session is persistent,		* New to NFSv4.1. If session is persistent,
	skipping to change at line 31750 ¶		skipping to change at line 32037 ¶
	* to file. Ordinary OPEN of the		* to file. Ordinary OPEN of the
	* specified file by current filehandle.		* specified file by current filehandle.
	*/		*/
	case CLAIM_FH: /* new to v4.1 */		case CLAIM_FH: /* new to v4.1 */
	/* CURRENT_FH: regular file to open */		/* CURRENT_FH: regular file to open */
	void;		void;
	/*		/*
	* Like CLAIM_DELEGATE_PREV. Right to file based on a		* Like CLAIM_DELEGATE_PREV. Right to file based on a
	* delegation granted to a previous boot		* delegation granted to a previous boot
	* instance of the client. File is identified by		* instance of the client. File is identified
	* by filehandle.		* by filehandle.
	*/		*/
	case CLAIM_DELEG_PREV_FH: /* new to v4.1 */		case CLAIM_DELEG_PREV_FH: /* new to v4.1 */
	/* CURRENT_FH: file being opened */		/* CURRENT_FH: file being opened */
	void;		void;
	/*		/*
	* Like CLAIM_DELEGATE_CUR. Right to file based on		* Like CLAIM_DELEGATE_CUR. Right to file based on
	* a delegation granted by the server.		* a delegation granted by the server.
	* File is identified by filehandle.		* File is identified by filehandle.
	skipping to change at line 31778 ¶		skipping to change at line 32065 ¶
	/*		/*
	* OPEN: Open a file, potentially receiving an OPEN delegation		* OPEN: Open a file, potentially receiving an OPEN delegation
	*/		*/
	struct OPEN4args {		struct OPEN4args {
	seqid4 seqid;		seqid4 seqid;
	uint32_t share_access;		uint32_t share_access;
	uint32_t share_deny;		uint32_t share_deny;
	open_owner4 owner;		open_owner4 owner;
	openflag4 openhow;		openflag4 openhow;
	open_claim4 claim;		open_claim4 claim;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_OPEN_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_OPEN_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct open_read_delegation4 {		struct open_read_delegation4 {
	stateid4 stateid; /* Stateid for delegation*/		stateid4 stateid; /* Stateid for delegation*/
	bool recall; /* Pre-recalled flag for		bool recall; /* Pre-recalled flag for
	delegations obtained		delegations obtained
	by reclaim (CLAIM_PREVIOUS) */		by reclaim (CLAIM_PREVIOUS) */
	nfsace4 permissions; /* Defines users who don't		nfsace4 permissions; /* Defines users who don't
	need an ACCESS call to		need an ACCESS call to
	open for read */		open for read */
	};		};
	skipping to change at line 31884 ¶		skipping to change at line 32167 ¶
	open_delegation4 delegation; /* Info on any open		open_delegation4 delegation; /* Info on any open
	delegation */		delegation */
	};		};
	union OPEN4res switch (nfsstat4 status) {		union OPEN4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	/* New CURRENT_FH: opened file */		/* New CURRENT_FH: opened file */
	OPEN4resok resok4;		OPEN4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_OPEN_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_OPEN_DESCRIPTION" title="DESCRIPTION">
	<t>
	The OPEN operation opens a regular file in a		The OPEN operation opens a regular file in a
	directory with the provided name or filehandle.		directory with the provided name or filehandle.
	OPEN can also create a file if a name is provided,		OPEN can also create a file if a name is provided,
	and the client specifies it wants to create a file.		and the client specifies it wants to create a file.
	Specification of whether or not a file is to be created,		Specification of whether or not a file is to be created,
	and the method of creation is via the openhow		and the method of creation is via the openhow
	parameter. The openhow parameter consists of		parameter. The openhow parameter consists of
	a switched union (data type opengflag4), which		a switched union (data type opengflag4), which
	switches on the value of opentype (OPEN4_NOCREATE		switches on the value of opentype (OPEN4_NOCREATE
	or OPEN4_CREATE). If OPEN4_CREATE is specified,		or OPEN4_CREATE). If OPEN4_CREATE is specified,
	this leads to another switched union (data type		this leads to another switched union (data type
	createhow4) that supports four cases of creation		createhow4) that supports four cases of creation
	methods: UNCHECKED4, GUARDED4, EXCLUSIVE4,		methods: UNCHECKED4, GUARDED4, EXCLUSIVE4,
	or EXCLUSIVE4_1. If opentype is OPEN4_CREATE,		or EXCLUSIVE4_1. If opentype is OPEN4_CREATE,
	then the claim field of the claim field		then the claim field of the claim field
	MUST be one of CLAIM_NULL, CLAIM_DELEGATE_CUR, or		<bcp14>MUST</bcp14> be one of CLAIM_NULL, CLAIM_DELEGATE_CUR, or
	CLAIM_DELEGATE_PREV, because these claim methods		CLAIM_DELEGATE_PREV, because these claim methods
	include a component of a file name.		include a component of a file name.
	</t>		</t>
	<t>		<t>
	Upon success (which might entail creation of a new		Upon success (which might entail creation of a new
	file), the current filehandle is replaced by that		file), the current filehandle is replaced by that
	of the created or existing object.		of the created or existing object.
	</t>		</t>
			<t>
	<t>
	If the current filehandle is a named attribute		If the current filehandle is a named attribute
	directory, OPEN will then create or open a named		directory, OPEN will then create or open a named
	attribute file. Note that exclusive create		attribute file. Note that exclusive create
	of a named attribute is not supported. If the		of a named attribute is not supported. If the
	createmode is EXCLUSIVE4 or EXCLUSIVE4_1 and the		createmode is EXCLUSIVE4 or EXCLUSIVE4_1 and the
	current filehandle is a named attribute directory,		current filehandle is a named attribute directory,
	the server will return EINVAL.		the server will return EINVAL.
	</t>		</t>
			<t>
	<t>
	UNCHECKED4 means that the file should be created if a		UNCHECKED4 means that the file should be created if a
	file of that name does not exist and encountering an		file of that name does not exist and encountering an
	existing regular file of that name is not an error.		existing regular file of that name is not an error.
	For this type of create, createattrs specifies the		For this type of create, createattrs specifies the
	initial set of attributes for the file. The set		initial set of attributes for the file. The set
	of attributes may include any writable attribute		of attributes may include any writable attribute
	valid for regular files. When an UNCHECKED4		valid for regular files. When an UNCHECKED4
	create encounters an existing file, the attributes		create encounters an existing file, the attributes
	specified by createattrs are not used, except that		specified by createattrs are not used, except that
	when createattrs specifies the size attribute		when createattrs specifies the size attribute
	with a size of zero, the existing file is truncated.		with a size of zero, the existing file is truncated.
	</t>		</t>
	<t>		<t>
	If GUARDED4 is specified, the server checks for		If GUARDED4 is specified, the server checks for
	the presence of a duplicate object by name before		the presence of a duplicate object by name before
	performing the create. If a duplicate exists,		performing the create. If a duplicate exists,
	NFS4ERR_EXIST is returned.		NFS4ERR_EXIST is returned.
	If the object does not exist, the request is		If the object does not exist, the request is
	performed as described for UNCHECKED4.		performed as described for UNCHECKED4.
	</t>		</t>
	<t>		<t>
	For the UNCHECKED4 and GUARDED4 cases, where the		For the UNCHECKED4 and GUARDED4 cases, where the
	operation is successful, the server will return		operation is successful, the server will return
	to the client an attribute mask signifying which		to the client an attribute mask signifying which
	attributes were successfully set for the object.		attributes were successfully set for the object.
	</t>		</t>
			<t>
	<t>
	EXCLUSIVE4_1 and EXCLUSIVE4		EXCLUSIVE4_1 and EXCLUSIVE4
	specify that the server is to follow exclusive		specify that the server is to follow exclusive
	creation semantics, using the verifier to ensure		creation semantics, using the verifier to ensure
	exclusive creation of the target. The server should		exclusive creation of the target. The server should
	check for the presence of a duplicate object by name.		check for the presence of a duplicate object by name.
	If the object does not exist, the server creates		If the object does not exist, the server creates
	the object and stores the verifier with the object.		the object and stores the verifier with the object.
	If the object does exist and the stored verifier		If the object does exist and the stored verifier
	matches the client provided verifier, the server		matches the client provided verifier, the server
	uses the existing object as the newly created object.		uses the existing object as the newly created object.
	If the stored verifier does not match, then an error		If the stored verifier does not match, then an error
	of NFS4ERR_EXIST is returned.		of NFS4ERR_EXIST is returned.
	</t>		</t>
	<t>		<t>
	If using EXCLUSIVE4, and if the server uses attributes to		If using EXCLUSIVE4, and if the server uses attributes to
	store the exclusive create verifier, the server will signify		store the exclusive create verifier, the server will signify
	which attributes it used by setting the appropriate bits in		which attributes it used by setting the appropriate bits in
	the attribute mask that is returned in the results.		the attribute mask that is returned in the results.
	Unlike UNCHECKED4, GUARDED4, and EXCLUSIVE4_1, EXCLUSIVE4 does		Unlike UNCHECKED4, GUARDED4, and EXCLUSIVE4_1, EXCLUSIVE4 does
	not support the setting of attributes at file creation, and		not support the setting of attributes at file creation, and
	after a successful OPEN via EXCLUSIVE4, the client MUST		after a successful OPEN via EXCLUSIVE4, the client <bcp14>MUST</bcp14>
	send a SETATTR to set attributes to a known state.		send a SETATTR to set attributes to a known state.
	</t>		</t>
	<t>		<t>
	In NFSv4.1, EXCLUSIVE4 has been deprecated in favor		In NFSv4.1, EXCLUSIVE4 has been deprecated in favor
	of EXCLUSIVE4_1.		of EXCLUSIVE4_1.
	Unlike EXCLUSIVE4, attributes may be provided		Unlike EXCLUSIVE4, attributes may be provided
	in the EXCLUSIVE4_1 case, but because the server		in the EXCLUSIVE4_1 case, but because the server
	may use attributes of the target object to store		may use attributes of the target object to store
	the verifier, the set of allowable attributes		the verifier, the set of allowable attributes
	may be fewer than the set of attributes SETATTR		may be fewer than the set of attributes SETATTR
	allows. The allowable attributes for EXCLUSIVE4_1		allows. The allowable attributes for EXCLUSIVE4_1
	are indicated in the suppattr_exclcreat (<xref		are indicated in the suppattr_exclcreat (<xref target="attrdef_suppattr_ex
	target="attrdef_suppattr_exclcreat"/>) attribute. If the client		clcreat" format="default"/>) attribute. If the client
	attempts to set in cva_attrs an attribute that is not in		attempts to set in cva_attrs an attribute that is not in
	suppattr_exclcreat, the server MUST return NFS4ERR_INVAL.		suppattr_exclcreat, the server <bcp14>MUST</bcp14> return NFS4ERR_INVAL.
	The response field, attrset, indicates both which attributes		The response field, attrset, indicates both which attributes
	the server set from cva_attrs and which attributes the		the server set from cva_attrs and which attributes the
	server used to store the verifier. As described		server used to store the verifier. As described
	in <xref target="OP_OPEN_IMPLEMENTATION"/>, the client can compare		in <xref target="OP_OPEN_IMPLEMENTATION" format="default"/>, the client ca n compare
	cva_attrs.attrmask with attrset to determine which attributes		cva_attrs.attrmask with attrset to determine which attributes
	were used to store the verifier.		were used to store the verifier.
	</t>		</t>
	<t>		<t>
	With the addition of persistent sessions and		With the addition of persistent sessions and
	pNFS, under some conditions EXCLUSIVE4 MUST NOT		pNFS, under some conditions EXCLUSIVE4 <bcp14>MUST NOT</bcp14>
	be used by the client or supported by the server.		be used by the client or supported by the server.
	The following table summarizes the appropriate and		The following table summarizes the appropriate and
	mandated exclusive create methods for implementations		mandated exclusive create methods for implementations
	of NFSv4.1:		of NFSv4.1:
	</t>		</t>
			<table anchor="exclusive_create" align="center">
	<texttable anchor='exclusive_create'>		<name>Required Methods for Exclusive Create</name>
			<thead>
	<preamble>		<tr>
	Required methods for exclusive create		<th align="left">Persistent Reply Cache Enabled</th>
	</preamble>		<th align="left">Server Supports pNFS</th>
			<th align="left">Server <bcp14>REQUIRED</bcp14></th>
	<ttcol>Persistent Reply Cache Enabled</ttcol>		<th align="left">Client Allowed</th>
	<ttcol>Server Supports pNFS</ttcol>		</tr>
	<ttcol>Server REQUIRED</ttcol> <ttcol>Client Allowed</ttcol>		</thead>
			<tbody>
	<c>no</c> <c>no</c>		<tr>
	<c>EXCLUSIVE4_1 and EXCLUSIVE4</c>		<td align="left">no</td>
	<c>EXCLUSIVE4_1 (SHOULD) or EXCLUSIVE4 (SHOULD NOT)</c>		<td align="left">no</td>
			<td align="left">EXCLUSIVE4_1 and EXCLUSIVE4</td>
	<c>no</c> <c>yes</c>		<td align="left">EXCLUSIVE4_1 (<bcp14>SHOULD</bcp14>) or EXCLUSI
	<c>EXCLUSIVE4_1</c>		VE4 (<bcp14>SHOULD NOT</bcp14>)</td>
	<c>EXCLUSIVE4_1</c>		</tr>
			<tr>
	<c>yes</c> <c>no</c>		<td align="left">no</td>
	<c>GUARDED4</c>		<td align="left">yes</td>
	<c>GUARDED4</c>		<td align="left">EXCLUSIVE4_1</td>
			<td align="left">EXCLUSIVE4_1</td>
	<c>yes</c> <c>yes</c>		</tr>
	<c>GUARDED4</c>		<tr>
	<c>GUARDED4</c>		<td align="left">yes</td>
			<td align="left">no</td>
	</texttable>		<td align="left">GUARDED4</td>
			<td align="left">GUARDED4</td>
	<t>		</tr>
			<tr>
			<td align="left">yes</td>
			<td align="left">yes</td>
			<td align="left">GUARDED4</td>
			<td align="left">GUARDED4</td>
			</tr>
			</tbody>
			</table>
			<t>
	If CREATE_SESSION4_FLAG_PERSIST is set in the results		If CREATE_SESSION4_FLAG_PERSIST is set in the results
	of CREATE_SESSION, the reply cache is persistent (see <xref target="OP_CREA TE_SESSION"/>).		of CREATE_SESSION, the reply cache is persistent (see <xref target="OP_CREA TE_SESSION" format="default"/>).
	If the EXCHGID4_FLAG_USE_PNFS_MDS flag is set in the		If the EXCHGID4_FLAG_USE_PNFS_MDS flag is set in the
	results from EXCHANGE_ID, the server is a pNFS server (see <xref target="OP _EXCHANGE_ID"/>).		results from EXCHANGE_ID, the server is a pNFS server (see <xref target="OP _EXCHANGE_ID" format="default"/>).
	If the client attempts to use EXCLUSIVE4 on a persistent session,		If the client attempts to use EXCLUSIVE4 on a persistent session,
	or a session derived from an		or a session derived from an
	EXCHGID4_FLAG_USE_PNFS_MDS client ID, the server MUST return		EXCHGID4_FLAG_USE_PNFS_MDS client ID, the server <bcp14>MUST</bcp14> return
	NFS4ERR_INVAL.		NFS4ERR_INVAL.
	</t>		</t>
			<t>
	<t>
	With persistent sessions, exclusive create semantics		With persistent sessions, exclusive create semantics
	are fully achievable via GUARDED4, and so EXCLUSIVE4		are fully achievable via GUARDED4, and so EXCLUSIVE4
	or EXCLUSIVE4_1 MUST NOT be used. When pNFS is		or EXCLUSIVE4_1 <bcp14>MUST NOT</bcp14> be used. When pNFS is
	being used, the layout_hint attribute might		being used, the layout_hint attribute might
	not be supported after the file is created. Only the		not be supported after the file is created. Only the
	EXCLUSIVE4_1 and GUARDED methods of exclusive file		EXCLUSIVE4_1 and GUARDED methods of exclusive file
	creation allow the atomic setting of attributes.		creation allow the atomic setting of attributes.
	</t>		</t>
			<t>
	<t>
	For the target directory, the server returns change_info4 information		For the target directory, the server returns change_info4 information
	in cinfo. With the atomic field of the change_info4 data type, the		in cinfo. With the atomic field of the change_info4 data type, the
	server will indicate if the before and after change attributes were		server will indicate if the before and after change attributes were
	obtained atomically with respect to the link creation.		obtained atomically with respect to the link creation.
	</t>		</t>
	<t>		<t>
	The OPEN operation provides for Windows share		The OPEN operation provides for Windows share
	reservation capability with the use of the		reservation capability with the use of the
	share_access and share_deny fields of the OPEN		share_access and share_deny fields of the OPEN
	arguments. The client specifies at OPEN the required		arguments. The client specifies at OPEN the required
	share_access and share_deny modes. For clients		share_access and share_deny modes. For clients
	that do not directly support SHAREs (i.e., UNIX), the		that do not directly support SHAREs (i.e., UNIX), the
	expected deny value is OPEN4_SHARE_DENY_NONE. In the case that		expected deny value is OPEN4_SHARE_DENY_NONE. In the case that
	there is an existing SHARE reservation that conflicts		there is an existing SHARE reservation that conflicts
	with the OPEN request, the server returns the error		with the OPEN request, the server returns the error
	NFS4ERR_SHARE_DENIED. For additional discussion of		NFS4ERR_SHARE_DENIED. For additional discussion of
	SHARE semantics, see <xref target="share_reserve" />.		SHARE semantics, see <xref target="share_reserve" format="default"/>.
	</t>		</t>
	<t>		<t>
	For each OPEN, the client provides a value for		For each OPEN, the client provides a value for
	the owner field of the OPEN argument. The owner		the owner field of the OPEN argument. The owner
	field is of data type open_owner4, and contains a		field is of data type open_owner4, and contains a
	field called clientid and a field called owner. The		field called clientid and a field called owner. The
	client can set the clientid field to any value and		client can set the clientid field to any value and
	the server MUST ignore it. Instead, the server MUST		the server <bcp14>MUST</bcp14> ignore it. Instead, the server <bcp14>MUST </bcp14>
	derive the client ID from the session ID of the		derive the client ID from the session ID of the
	SEQUENCE operation of the COMPOUND request.		SEQUENCE operation of the COMPOUND request.
	</t>		</t>
	<t>		<t>
	The "seqid" field of the request is not used in		The "seqid" field of the request is not used in
	NFSv4.1, but it MAY be any value and the server MUST		NFSv4.1, but it <bcp14>MAY</bcp14> be any value and the server <bcp14>MUST </bcp14>
	ignore it.		ignore it.
	</t>		</t>
	<t>		<t>
	In the case that the client is recovering state from a server failure,		In the case that the client is recovering state from a server failure,
	the claim field of the OPEN argument is used to signify that the		the claim field of the OPEN argument is used to signify that the
	request is meant to reclaim state previously held.		request is meant to reclaim state previously held.
	</t>		</t>
	<t>		<t>
	The "claim" field of the OPEN argument is used to specify the file to		The "claim" field of the OPEN argument is used to specify the file to
	be opened and the state information that the client claims to		be opened and the state information that the client claims to
	possess. There are seven claim types as follows:		possess. There are seven claim types as follows:
	</t>		</t>
	<texttable>		<table align="center">
	<ttcol align='left'>open type</ttcol>		<thead>
	<ttcol align='left'>description</ttcol>		<tr>
	<c>		<th align="left">open type</th>
			<th align="left">description</th>
			</tr>
			</thead>
			<tbody>
			<tr>
			<td align="left">
	CLAIM_NULL,		CLAIM_NULL,
	CLAIM_FH		CLAIM_FH
	</c>		</td>
	<c>		<td align="left">
	For the client, this is a new OPEN request and there is no		For the client, this is a new OPEN request and there is no
	previous state associated with the file for the client. With		previous state associated with the file for the client. With
	CLAIM_NULL, the file is identified by the current filehandle		CLAIM_NULL, the file is identified by the current filehandle
	and the specified component name. With CLAIM_FH (new to NFSv4.1),		and the specified component name. With CLAIM_FH (new to NFSv4.1),
	the file is identified by just the current filehandle.		the file is identified by just the current filehandle.
	</c>		</td>
	<c>		</tr>
			<tr>
			<td align="left">
	CLAIM_PREVIOUS		CLAIM_PREVIOUS
	</c>		</td>
	<c>		<td align="left">
	The client is claiming basic OPEN state for a file that was held		The client is claiming basic OPEN state for a file that was held
	previous to a server restart. Generally used when a server is		previous to a server restart. Generally used when a server is
	returning persistent filehandles; the client may not have the file		returning persistent filehandles; the client may not have the file
	name to reclaim the OPEN.		name to reclaim the OPEN.
	</c>		</td>
	<c>		</tr>
			<tr>
			<td align="left">
	CLAIM_DELEGATE_CUR,		CLAIM_DELEGATE_CUR,
	CLAIM_DELEG_CUR_FH		CLAIM_DELEG_CUR_FH
	</c>		</td>
	<c>		<td align="left">
	The client is claiming a delegation for OPEN		The client is claiming a delegation for OPEN
	as granted by the server. Generally, this		as granted by the server. Generally, this
	is done as part of recalling a delegation. With		is done as part of recalling a delegation. With
	CLAIM_DELEGATE_CUR, the file is identified by		CLAIM_DELEGATE_CUR, the file is identified by
	the current filehandle and the specified component		the current filehandle and the specified component
	name. With CLAIM_DELEG_CUR_FH (new to NFSv4.1), the		name. With CLAIM_DELEG_CUR_FH (new to NFSv4.1), the
	file is identified by just the current filehandle.		file is identified by just the current filehandle.
	</c>		</td>
	<c>		</tr>
			<tr>
			<td align="left">
	CLAIM_DELEGATE_PREV,		CLAIM_DELEGATE_PREV,
	CLAIM_DELEG_PREV_FH		CLAIM_DELEG_PREV_FH
	</c>		</td>
	<c>		<td align="left">
	The client is claiming a delegation granted to a		The client is claiming a delegation granted to a
	previous client instance; used after the client		previous client instance; used after the client
	restarts. The server MAY support CLAIM_DELEGATE_PREV		restarts. The server <bcp14>MAY</bcp14> support CLAIM_DELEGATE_PREV
	and/or CLAIM_DELEG_PREV_FH (new to NFSv4.1). If it		and/or CLAIM_DELEG_PREV_FH (new to NFSv4.1). If it
	does support either claim type, CREATE_SESSION MUST		does support either claim type, CREATE_SESSION <bcp14>MUST
	NOT remove the client's delegation state, and the		NOT</bcp14> remove the client's delegation state, and the
	server MUST support the DELEGPURGE operation.		server <bcp14>MUST</bcp14> support the DELEGPURGE operation.
	</c>
	</texttable>
	<t>		</td>
			</tr>
			</tbody>
			</table>
			<t>
	For OPEN requests that reach the server during		For OPEN requests that reach the server during
	the grace period, the server returns an error		the grace period, the server returns an error
	of NFS4ERR_GRACE. The following claim types are		of NFS4ERR_GRACE. The following claim types are
	exceptions:		exceptions:
	<list style='symbols'>		</t>
			<ul spacing="normal">
	<t>		<li>
	OPEN requests specifying the claim type CLAIM_PREVIOUS are devoted to		OPEN requests specifying the claim type CLAIM_PREVIOUS are devoted to
	reclaiming opens after a server restart and are typically only		reclaiming opens after a server restart and are typically only
	valid during the grace period.		valid during the grace period.
	</t>		</li>
			<li>
	<t>
	OPEN requests specifying the claim types CLAIM_DELEGATE_CUR and		OPEN requests specifying the claim types CLAIM_DELEGATE_CUR and
	CLAIM_DELEG_CUR_FH are valid both during and after the grace period.		CLAIM_DELEG_CUR_FH are valid both during and after the grace period.
	Since the granting of the delegation that they are subordinate		Since the granting of the delegation that they are subordinate
	to assures that there is no conflict with locks to be reclaimed		to assures that there is no conflict with locks to be reclaimed
	by other clients, the server need not return NFS4ERR_GRACE when		by other clients, the server need not return NFS4ERR_GRACE when
	these are received during the grace period.		these are received during the grace period.
	</t>		</li>
	</list>		</ul>
			<t>
	</t>
	<t>
	For any OPEN request, the server may return an OPEN delegation, which		For any OPEN request, the server may return an OPEN delegation, which
	allows further opens and closes to be handled locally on the client as		allows further opens and closes to be handled locally on the client as
	described in <xref target="open_delegation"/>. Note that delegation is		described in <xref target="open_delegation" format="default"/>. Note that delegation is
	up to the server to decide. The client should never assume that		up to the server to decide. The client should never assume that
	delegation will or will not be granted in a particular instance. It		delegation will or will not be granted in a particular instance. It
	should always be prepared for either case. A partial exception is the		should always be prepared for either case. A partial exception is the
	reclaim (CLAIM_PREVIOUS) case, in which a delegation type is claimed.		reclaim (CLAIM_PREVIOUS) case, in which a delegation type is claimed.
	In this case, delegation will always be granted, although the server		In this case, delegation will always be granted, although the server
	may specify an immediate recall in the delegation structure.		may specify an immediate recall in the delegation structure.
	</t>		</t>
	<t>		<t>
	The rflags returned by a successful OPEN allow the server to return		The rflags returned by a successful OPEN allow the server to return
	information governing how the open file is to be handled.		information governing how the open file is to be handled.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	OPEN4_RESULT_CONFIRM is deprecated and MUST NOT be returned		<li>
			OPEN4_RESULT_CONFIRM is deprecated and <bcp14>MUST NOT</bcp14> be returned
	by an NFSv4.1 server.		by an NFSv4.1 server.
	</t>		</li>
	<t>		<li>
	OPEN4_RESULT_LOCKTYPE_POSIX indicates that the server's byte-range locking		OPEN4_RESULT_LOCKTYPE_POSIX indicates that the server's byte-range locking
	behavior supports the complete set of POSIX locking techniques <xref targe t="fcntl"/>. From		behavior supports the complete set of POSIX locking techniques <xref targe t="fcntl" format="default"/>. From
	this, the client can choose to manage byte-range locking state in a way to		this, the client can choose to manage byte-range locking state in a way to
	handle a mismatch of byte-range locking management.		handle a mismatch of byte-range locking management.
	</t>		</li>
	<t>		<li>
	OPEN4_RESULT_PRESERVE_UNLINKED indicates that the server will		OPEN4_RESULT_PRESERVE_UNLINKED indicates that the server will
	preserve the open file if the client (or any other client)		preserve the open file if the client (or any other client)
	removes the file as long as it is open. Furthermore, the		removes the file as long as it is open. Furthermore, the
	server promises to preserve the file through the		server promises to preserve the file through the
	grace period after server restart, thereby giving the client		grace period after server restart, thereby giving the client
	the opportunity to reclaim its open.		the opportunity to reclaim its open.
	</t>		</li>
	<t>		<li>
	OPEN4_RESULT_MAY_NOTIFY_LOCK indicates that the server may attempt		OPEN4_RESULT_MAY_NOTIFY_LOCK indicates that the server may attempt
	CB_NOTIFY_LOCK callbacks for locks on this file. This flag is a hint		CB_NOTIFY_LOCK callbacks for locks on this file. This flag is a hint
	only, and may be safely ignored by the client.		only, and may be safely ignored by the client.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	If the component is of zero length, NFS4ERR_INVAL will be returned.		If the component is of zero length, NFS4ERR_INVAL will be returned.
	The component is also subject to the normal UTF-8, character support,		The component is also subject to the normal UTF-8, character support,
	and name checks. See <xref target="utf8_related_errors" /> for		and name checks. See <xref target="utf8_related_errors" format="default"/ > for
	further discussion.		further discussion.
	</t>		</t>
	<t>		<t>
	When an OPEN is done and the specified open-owner already has the		When an OPEN is done and the specified open-owner already has the
	resulting filehandle open, the result is to "OR" together the new		resulting filehandle open, the result is to "OR" together the new
	share and deny status together with the existing status. In this		share and deny status together with the existing status. In this
	case, only a single CLOSE need be done, even though multiple OPENs		case, only a single CLOSE need be done, even though multiple OPENs
	were completed. When such an OPEN is done, checking of share		were completed. When such an OPEN is done, checking of share
	reservations for the new OPEN proceeds normally, with no exception for		reservations for the new OPEN proceeds normally, with no exception for
	the existing OPEN held by the same open-owner. In this case, the		the existing OPEN held by the same open-owner. In this case, the
	stateid returned as an "other" field that matches that of the previous		stateid returned as an "other" field that matches that of the previous
	open while the "seqid" field is incremented to reflect the change		open while the "seqid" field is incremented to reflect the change
	status due to the new open.		status due to the new open.
	</t>		</t>
	<t>		<t>
	If the underlying file system at the server is only accessible in a		If the underlying file system at the server is only accessible in a
	read-only mode and the OPEN request has specified ACCESS_WRITE or		read-only mode and the OPEN request has specified ACCESS_WRITE or
	ACCESS_BOTH, the server will return NFS4ERR_ROFS to indicate a		ACCESS_BOTH, the server will return NFS4ERR_ROFS to indicate a
	read-only file system.		read-only file system.
	</t>		</t>
	<t>		<t>
	As with the CREATE operation, the server MUST derive		As with the CREATE operation, the server <bcp14>MUST</bcp14> derive
	the owner, owner ACE, group, or group ACE if any		the owner, owner ACE, group, or group ACE if any
	of the four attributes are required and supported		of the four attributes are required and supported
	by the server's file system. For an OPEN with the		by the server's file system. For an OPEN with the
	EXCLUSIVE4 createmode, the server has no choice,		EXCLUSIVE4 createmode, the server has no choice,
	since such OPEN calls do not include the createattrs		since such OPEN calls do not include the createattrs
	field. Conversely, if createattrs (UNCHECKED4 or		field. Conversely, if createattrs (UNCHECKED4 or
	GUARDED4) or cva_attrs (EXCLUSIVE4_1) is specified,		GUARDED4) or cva_attrs (EXCLUSIVE4_1) is specified,
	and includes an owner, owner_group, or ACE that		and includes an owner, owner_group, or ACE that
	the principal in the RPC call's credentials does		the principal in the RPC call's credentials does
	not have authorization to create files for, then		not have authorization to create files for, then
	the server may return NFS4ERR_PERM.		the server may return NFS4ERR_PERM.
	</t>		</t>
	<t>		<t>
	In the case of an OPEN that specifies a size of zero (e.g., truncation)		In the case of an OPEN that specifies a size of zero (e.g., truncation)
	and the file has named attributes, the named attributes are left as		and the file has named attributes, the named attributes are left as
	is and are not removed.		is and are not removed.
	</t>		</t>
			<t>
	<t>
	NFSv4.1 gives more precise control to clients over		NFSv4.1 gives more precise control to clients over
	acquisition of delegations via the following new		acquisition of delegations via the following new
	flags for the share_access field of OPEN4args:		flags for the share_access field of OPEN4args:
	<list style="hanging">		</t>
	<t hangText="OPEN4_SHARE_ACCESS_WANT_READ_DELEG"></t>
	<t hangText="OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG"></t>		<t>OPEN4_SHARE_ACCESS_WANT_READ_DELEG</t>
	<t hangText="OPEN4_SHARE_ACCESS_WANT_ANY_DELEG"></t>		<t>OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG</t>
	<t hangText="OPEN4_SHARE_ACCESS_WANT_NO_DELEG"></t>		<t>OPEN4_SHARE_ACCESS_WANT_ANY_DELEG</t>
	<t hangText="OPEN4_SHARE_ACCESS_WANT_CANCEL"></t>		<t>OPEN4_SHARE_ACCESS_WANT_NO_DELEG</t>
	<t hangText="OPEN4_SHARE_ACCESS_WANT_SIGNAL_DELEG_WHEN_RESRC_AVAIL"></t>		<t>OPEN4_SHARE_ACCESS_WANT_CANCEL</t>
	<t hangText="OPEN4_SHARE_ACCESS_WANT_PUSH_DELEG_WHEN_UNCONTENDED"></t>		<t>OPEN4_SHARE_ACCESS_WANT_SIGNAL_DELEG_WHEN_RESRC_AVAIL</t>
	</list>		<t>OPEN4_SHARE_ACCESS_WANT_PUSH_DELEG_WHEN_UNCONTENDED</t>
	</t>
	<t>		<t>
	If (share_access &amp; OPEN4_SHARE_ACCESS_WANT_DELEG_MASK) is		If (share_access &amp; OPEN4_SHARE_ACCESS_WANT_DELEG_MASK) is
	not zero, then the client will have specified one and only one of:		not zero, then the client will have specified one and only one of:
	<list style="hanging">		</t>
	<t hangText="OPEN4_SHARE_ACCESS_WANT_READ_DELEG"></t>
	<t hangText="OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG"></t>		<t>OPEN4_SHARE_ACCESS_WANT_READ_DELEG</t>
	<t hangText="OPEN4_SHARE_ACCESS_WANT_ANY_DELEG"></t>		<t>OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG</t>
	<t hangText="OPEN4_SHARE_ACCESS_WANT_NO_DELEG"></t>		<t>OPEN4_SHARE_ACCESS_WANT_ANY_DELEG</t>
	<t hangText="OPEN4_SHARE_ACCESS_WANT_CANCEL"></t>		<t>OPEN4_SHARE_ACCESS_WANT_NO_DELEG</t>
	</list>		<t>OPEN4_SHARE_ACCESS_WANT_CANCEL</t>
			<t>
	Otherwise, the client is neither indicating a desire nor a non-desire		Otherwise, the client is neither indicating a desire nor a non-desire
	for a delegation, and the server MAY or MAY not return a delegation		for a delegation, and the server <bcp14>MAY</bcp14> or
			<bcp14>MAY</bcp14> not return a delegation
	in the OPEN response.		in the OPEN response.
	</t>		</t>
	<t>		<t>
	If the server supports the new _WANT_ flags and the		If the server supports the new _WANT_ flags and the
	client sends one or more of the new flags,		client sends one or more of the new flags,
	then in the event the server does not return a		then in the event the server does not return a
	delegation, it MUST return a delegation type of		delegation, it <bcp14>MUST</bcp14> return a delegation type of
	OPEN_DELEGATE_NONE_EXT. The field ond_why in the reply		OPEN_DELEGATE_NONE_EXT. The field ond_why in the reply
	indicates why		indicates why
	no delegation was returned and will be one of:		no delegation was returned and will be one of:
	<list style="hanging">		</t>
	<t hangText="WND4_NOT_WANTED">
			<dl newline="true" spacing="normal">
			<dt>WND4_NOT_WANTED</dt>
			<dd>
	The client specified OPEN4_SHARE_ACCESS_WANT_NO_DELEG.		The client specified OPEN4_SHARE_ACCESS_WANT_NO_DELEG.
	</t>		</dd>
	<t hangText="WND4_CONTENTION">		<dt>WND4_CONTENTION</dt>
			<dd>
	There is a conflicting delegation or open on the file.		There is a conflicting delegation or open on the file.
	</t>		</dd>
	<t hangText="WND4_RESOURCE">		<dt>WND4_RESOURCE</dt>
			<dd>
	Resource limitations prevent the server from granting a		Resource limitations prevent the server from granting a
	delegation.		delegation.
	</t>		</dd>
	<t hangText="WND4_NOT_SUPP_FTYPE">		<dt>WND4_NOT_SUPP_FTYPE</dt>
			<dd>
	The server does not support delegations on this file type.		The server does not support delegations on this file type.
	</t>		</dd>
	<t hangText="WND4_WRITE_DELEG_NOT_SUPP_FTYPE">		<dt>WND4_WRITE_DELEG_NOT_SUPP_FTYPE</dt>
			<dd>
	The server does not support OPEN_DELEGATE_WRITE delegations on this fil e		The server does not support OPEN_DELEGATE_WRITE delegations on this fil e
	type.		type.
	</t>		</dd>
	<t hangText="WND4_NOT_SUPP_UPGRADE">		<dt>WND4_NOT_SUPP_UPGRADE</dt>
			<dd>
	The server does not support atomic upgrade of an OPEN_DELEGATE_READ del egation to an OPEN_DELEGATE_WRITE delegation.		The server does not support atomic upgrade of an OPEN_DELEGATE_READ del egation to an OPEN_DELEGATE_WRITE delegation.
	</t>		</dd>
	<t hangText="WND4_NOT_SUPP_DOWNGRADE">		<dt>WND4_NOT_SUPP_DOWNGRADE</dt>
			<dd>
	The server does not support atomic downgrade of an OPEN_DELEGATE_WRITE delegation to an OPEN_DELEGATE_READ delegation.		The server does not support atomic downgrade of an OPEN_DELEGATE_WRITE delegation to an OPEN_DELEGATE_READ delegation.
	</t>		</dd>
	<t hangText="WND4_CANCELED">		<dt>WND4_CANCELED</dt>
			<dd>
	The client specified OPEN4_SHARE_ACCESS_WANT_CANCEL and now		The client specified OPEN4_SHARE_ACCESS_WANT_CANCEL and now
	any "want" for this file object is cancelled.		any "want" for this file object is cancelled.
	</t>		</dd>
	<t hangText="WND4_IS_DIR">		<dt>WND4_IS_DIR</dt>
			<dd>
	The specified file object is a directory, and the operation		The specified file object is a directory, and the operation
	is OPEN or WANT_DELEGATION, which do not support delegations		is OPEN or WANT_DELEGATION, which do not support delegations
	on directories.		on directories.
	</t>		</dd>
	</list>		</dl>
	</t>		<t>
	<t>
	OPEN4_SHARE_ACCESS_WANT_READ_DELEG,		OPEN4_SHARE_ACCESS_WANT_READ_DELEG,
	OPEN_SHARE_ACCESS_WANT_WRITE_DELEG, or		OPEN_SHARE_ACCESS_WANT_WRITE_DELEG, or
	OPEN_SHARE_ACCESS_WANT_ANY_DELEG mean, respectively, the		OPEN_SHARE_ACCESS_WANT_ANY_DELEG mean, respectively, the
	client wants an OPEN_DELEGATE_READ, OPEN_DELEGATE_WRITE, or any delegati on regardless which		client wants an OPEN_DELEGATE_READ, OPEN_DELEGATE_WRITE, or any delegati on regardless which
	of OPEN4_SHARE_ACCESS_READ, OPEN4_SHARE_ACCESS_WRITE, or		of OPEN4_SHARE_ACCESS_READ, OPEN4_SHARE_ACCESS_WRITE, or
	OPEN4_SHARE_ACCESS_BOTH is set. If the client has an OPEN_DELEGATE_READ delegation on a file and requests an OPEN_DELEGATE_WRITE delegation, then		OPEN4_SHARE_ACCESS_BOTH is set. If the client has an OPEN_DELEGATE_READ delegation on a file and requests an OPEN_DELEGATE_WRITE delegation, then
	the client is requesting atomic upgrade of its OPEN_DELEGATE_READ delega tion		the client is requesting atomic upgrade of its OPEN_DELEGATE_READ delega tion
	to an OPEN_DELEGATE_WRITE delegation. If the client has an OPEN_DELEGATE _WRITE delegation on		to an OPEN_DELEGATE_WRITE delegation. If the client has an OPEN_DELEGATE _WRITE delegation on
	a file and requests an OPEN_DELEGATE_READ delegation, then the client is		a file and requests an OPEN_DELEGATE_READ delegation, then the client is
	requesting atomic downgrade to an OPEN_DELEGATE_READ delegation. A serve r MAY		requesting atomic downgrade to an OPEN_DELEGATE_READ delegation. A serve r <bcp14>MAY</bcp14>
	support atomic upgrade or downgrade. If it does, then the		support atomic upgrade or downgrade. If it does, then the
	returned delegation_type of OPEN_DELEGATE_READ		returned delegation_type of OPEN_DELEGATE_READ
	or OPEN_DELEGATE_WRITE that is different from the delegation		or OPEN_DELEGATE_WRITE that is different from the delegation
	type the client currently has, indicates successful upgrade		type the client currently has, indicates successful upgrade
	or downgrade. If the server does not support atomic delegation upgrade o r		or downgrade. If the server does not support atomic delegation upgrade o r
	downgrade, then ond_why will be set to WND4_NOT_SUPP_UPGRADE or		downgrade, then ond_why will be set to WND4_NOT_SUPP_UPGRADE or
	WND4_NOT_SUPP_DOWNGRADE.		WND4_NOT_SUPP_DOWNGRADE.
	</t>		</t>
	<t>		<t>
	OPEN4_SHARE_ACCESS_WANT_NO_DELEG means that the client wants no		OPEN4_SHARE_ACCESS_WANT_NO_DELEG means that the client wants no
	delegation.		delegation.
	</t>		</t>
	<t>		<t>
	OPEN4_SHARE_ACCESS_WANT_CANCEL means that the client wants no		OPEN4_SHARE_ACCESS_WANT_CANCEL means that the client wants no
	delegation and wants to cancel any previously registered		delegation and wants to cancel any previously registered
	"want" for a delegation.		"want" for a delegation.
	</t>		</t>
	<t>		<t>
	The client may set one or both of		The client may set one or both of
	OPEN4_SHARE_ACCESS_WANT_SIGNAL_DELEG_WHEN_RESRC_AVAIL and		OPEN4_SHARE_ACCESS_WANT_SIGNAL_DELEG_WHEN_RESRC_AVAIL and
	OPEN4_SHARE_ACCESS_WANT_PUSH_DELEG_WHEN_UNCONTENDED.		OPEN4_SHARE_ACCESS_WANT_PUSH_DELEG_WHEN_UNCONTENDED.
	However, they will have no effect unless one of following is set:		However, they will have no effect unless one of following is set:
	<list style="symbols">		</t>
	<t>OPEN4_SHARE_ACCESS_WANT_READ_DELEG</t>		<ul spacing="normal">
	<t>OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG</t>		<li>OPEN4_SHARE_ACCESS_WANT_READ_DELEG</li>
	<t>OPEN4_SHARE_ACCESS_WANT_ANY_DELEG</t>		<li>OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG</li>
	</list>		<li>OPEN4_SHARE_ACCESS_WANT_ANY_DELEG</li>
	</t>		</ul>
	<t>		<t>
	If the client specifies		If the client specifies
	OPEN4_SHARE_ACCESS_WANT_SIGNAL_DELEG_WHEN_RESRC_AVAIL, then it		OPEN4_SHARE_ACCESS_WANT_SIGNAL_DELEG_WHEN_RESRC_AVAIL, then it
	wishes to register a "want" for a delegation, in the event the		wishes to register a "want" for a delegation, in the event the
	OPEN results do not include a delegation. If so and the		OPEN results do not include a delegation. If so and the
	server denies the delegation due to insufficient resources,		server denies the delegation due to insufficient resources,
	the server MAY later inform the client, via the		the server <bcp14>MAY</bcp14> later inform the client, via the
	CB_RECALLABLE_OBJ_AVAIL operation, that the resource		CB_RECALLABLE_OBJ_AVAIL operation, that the resource
	limitation condition has eased. The server will tell the		limitation condition has eased. The server will tell the
	client that it intends to send a future		client that it intends to send a future
	CB_RECALLABLE_OBJ_AVAIL operation by setting delegation_type		CB_RECALLABLE_OBJ_AVAIL operation by setting delegation_type
	in the results to OPEN_DELEGATE_NONE_EXT, ond_why		in the results to OPEN_DELEGATE_NONE_EXT, ond_why
	to WND4_RESOURCE, and ond_server_will_signal_avail set to		to WND4_RESOURCE, and ond_server_will_signal_avail set to
	TRUE. If		TRUE. If
	ond_server_will_signal_avail is set to TRUE, the server MUST		ond_server_will_signal_avail is set to TRUE, the server <bcp14>MUST</bcp 14>
	later send a CB_RECALLABLE_OBJ_AVAIL operation.		later send a CB_RECALLABLE_OBJ_AVAIL operation.
	</t>		</t>
	<t>		<t>
	If the client specifies		If the client specifies
	OPEN4_SHARE_ACCESS_WANT_SIGNAL_DELEG_WHEN_UNCONTENDED, then it		OPEN4_SHARE_ACCESS_WANT_SIGNAL_DELEG_WHEN_UNCONTENDED, then it
	wishes to register a "want" for a delegation, in the event the		wishes to register a "want" for a delegation, in the event the
	OPEN results do not include a delegation. If so and the server		OPEN results do not include a delegation. If so and the server
	denies the delegation due to contention, the		denies the delegation due to contention, the
	server MAY later inform the client, via the CB_PUSH_DELEG		server <bcp14>MAY</bcp14> later inform the client, via the CB_PUSH_DELEG
	operation, that the contention condition		operation, that the contention condition
	has eased. The server will tell the client that it intends to		has eased. The server will tell the client that it intends to
	send a future CB_PUSH_DELEG operation by setting		send a future CB_PUSH_DELEG operation by setting
	delegation_type in the results to OPEN_DELEGATE_NONE_EXT,		delegation_type in the results to OPEN_DELEGATE_NONE_EXT,
	ond_why to WND4_CONTENTION, and		ond_why to WND4_CONTENTION, and
	ond_server_will_push_deleg to TRUE. If		ond_server_will_push_deleg to TRUE. If
	ond_server_will_push_deleg is TRUE, the server MUST later		ond_server_will_push_deleg is TRUE, the server <bcp14>MUST</bcp14> later
	send a CB_PUSH_DELEG operation.		send a CB_PUSH_DELEG operation.
	</t>		</t>
	<t>		<t>
	If the client has previously registered a want for a		If the client has previously registered a want for a
	delegation on a file, and then sends a request to register a		delegation on a file, and then sends a request to register a
	want for a delegation on the same file, the server MUST return		want for a delegation on the same file, the server <bcp14>MUST</bcp14> r eturn
	a new error: NFS4ERR_DELEG_ALREADY_WANTED. If the client		a new error: NFS4ERR_DELEG_ALREADY_WANTED. If the client
	wishes to register a different type of delegation want for the		wishes to register a different type of delegation want for the
	same file, it MUST cancel the existing delegation WANT.		same file, it <bcp14>MUST</bcp14> cancel the existing delegation WANT.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_OPEN_IMPLEMENTATION" title="IMPLEMENTATION">		<section toc="exclude" anchor="OP_OPEN_IMPLEMENTATION" numbered="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	In absence of a persistent session, the client		In absence of a persistent session, the client
	invokes exclusive create by setting the how parameter		invokes exclusive create by setting the how parameter
	to EXCLUSIVE4 or EXCLUSIVE4_1. In these cases, the		to EXCLUSIVE4 or EXCLUSIVE4_1. In these cases, the
	client provides a verifier that can reasonably be		client provides a verifier that can reasonably be
	expected to be unique. A combination of a client		expected to be unique. A combination of a client
	identifier, perhaps the client network address,		identifier, perhaps the client network address,
	and a unique number generated by the client, perhaps		and a unique number generated by the client, perhaps
	the RPC transaction identifier, may be appropriate.		the RPC transaction identifier, may be appropriate.
	</t>		</t>
	<t>		<t>
	If the object does not exist, the server creates the object and stores the		If the object does not exist, the server creates the object and stores the
	verifier in stable storage. For file systems that do not provide a		verifier in stable storage. For file systems that do not provide a
	mechanism for the storage of arbitrary file attributes, the server may		mechanism for the storage of arbitrary file attributes, the server may
	use one or more elements of the object's metadata to store the		use one or more elements of the object's metadata to store the
	verifier. The verifier MUST be stored in stable storage to prevent		verifier. The verifier <bcp14>MUST</bcp14> be stored in stable storage to prevent
	erroneous failure on retransmission of the request. It is assumed that		erroneous failure on retransmission of the request. It is assumed that
	an exclusive create is being performed because exclusive semantics are		an exclusive create is being performed because exclusive semantics are
	critical to the application. Because of the expected usage, exclusive		critical to the application. Because of the expected usage, exclusive
	CREATE does not rely solely on the server's reply cache		CREATE does not rely solely on the server's reply cache
	for storage of the verifier. A nonpersistent reply cache		for storage of the verifier. A nonpersistent reply cache
	does not survive a crash and the session and reply cache		does not survive a crash and the session and reply cache
	may be deleted after a network partition that exceeds the		may be deleted after a network partition that exceeds the
	lease time, thus opening failure windows.		lease time, thus opening failure windows.
	</t>		</t>
	<t>		<t>
	An NFSv4.1 server SHOULD NOT store the verifier in		An NFSv4.1 server <bcp14>SHOULD NOT</bcp14> store the verifier in
	any of the file's RECOMMENDED or REQUIRED attributes.		any of the file's <bcp14>RECOMMENDED</bcp14> or <bcp14>REQUIRED</bcp14> at
	If it does, the server SHOULD use time_modify_set or		tributes.
			If it does, the server <bcp14>SHOULD</bcp14> use time_modify_set or
	time_access_set to store the verifier.		time_access_set to store the verifier.
	The server SHOULD NOT store the verifier in the		The server <bcp14>SHOULD NOT</bcp14> store the verifier in the
	following attributes:		following attributes:
	<list style="empty">
	<t>acl (it is desirable for access control to
	be established at creation),</t>
	<t>dacl (ditto),</t>
	<t>mode (ditto),</t>
	<t>owner (ditto),</t>
	<t>owner_group (ditto),</t>
	<t>retentevt_set (it may be desired to
	establish retention at creation)</t>
	<t>retention_hold (ditto),</t>
	<t>retention_set (ditto),</t>
	<t>sacl (it is desirable for auditing control
	to be established at creation),</t>
	<t>size (on some servers, size may have a
	limited range of values),</t>
	<t>mode_set_masked (as with mode),
	<list style="empty">
	<t>and</t>
	</list>
	</t>		</t>
	<t>time_creation (a meaningful file creation		<ul empty="true" spacing="normal">
	should be set when the file is created).</t>		<li>acl (it is desirable for access control to
	</list>		be established at creation),</li>
			<li>dacl (ditto),</li>
			<li>mode (ditto),</li>
			<li>owner (ditto),</li>
			<li>owner_group (ditto),</li>
			<li>retentevt_set (it may be desired to
			establish retention at creation)</li>
			<li>retention_hold (ditto),</li>
			<li>retention_set (ditto),</li>
			<li>sacl (it is desirable for auditing control
			to be established at creation),</li>
			<li>size (on some servers, size may have a
			limited range of values),</li>
			<li>
			<t>mode_set_masked (as with mode),
			</t>
			<ul empty="true" spacing="normal">
			<li>and</li>
			</ul>
			</li>
			<li>time_creation (a meaningful file creation
			should be set when the file is created).</li>
			</ul>
			<t>
	Another alternative for the server is to use a named attribute		Another alternative for the server is to use a named attribute
	to store the verifier.		to store the verifier.
	</t>		</t>
			<t>
	<t>
	Because the EXCLUSIVE4 create method does not specify		Because the EXCLUSIVE4 create method does not specify
	initial attributes when processing an EXCLUSIVE4 create,		initial attributes when processing an EXCLUSIVE4 create,
	the server		the server
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	SHOULD set the		<li>
			<bcp14>SHOULD</bcp14> set the
	owner of the file to that corresponding to the credential of		owner of the file to that corresponding to the credential of
	request's RPC header.		request's RPC header.
	</t>		</li>
			<li>
	<t>		<bcp14>SHOULD NOT</bcp14> leave the file's access control to anyone
	SHOULD NOT leave the file's access control to anyone
	but the owner of the file.		but the owner of the file.
	</t>		</li>
	</list>		</ul>
			<t>
	</t>
	<t>
	If the server cannot support exclusive create		If the server cannot support exclusive create
	semantics, possibly because of the requirement to		semantics, possibly because of the requirement to
	commit the verifier to stable storage, it should fail		commit the verifier to stable storage, it should fail
	the OPEN request with the error NFS4ERR_NOTSUPP.		the OPEN request with the error NFS4ERR_NOTSUPP.
	</t>		</t>
	<t>		<t>
	During an exclusive CREATE request, if the object		During an exclusive CREATE request, if the object
	already exists, the server reconstructs the object's		already exists, the server reconstructs the object's
	verifier and compares it with the verifier in		verifier and compares it with the verifier in
	the request. If they match, the server treats the		the request. If they match, the server treats the
	request as a success. The request is presumed to		request as a success. The request is presumed to
	be a duplicate of an earlier, successful request		be a duplicate of an earlier, successful request
	for which the reply was lost and that the server		for which the reply was lost and that the server
	duplicate request cache mechanism did not detect. If		duplicate request cache mechanism did not detect. If
	the verifiers do not match, the request is rejected		the verifiers do not match, the request is rejected
	with the status NFS4ERR_EXIST.		with the status NFS4ERR_EXIST.
	</t>		</t>
	<t>		<t>
	After the client has performed a successful		After the client has performed a successful
	exclusive create, the attrset response indicates		exclusive create, the attrset response indicates
	which attributes were used to store the verifier.		which attributes were used to store the verifier.
	If EXCLUSIVE4 was used, the attributes set in		If EXCLUSIVE4 was used, the attributes set in
	attrset were used for the verifier. If EXCLUSIVE4_1		attrset were used for the verifier. If EXCLUSIVE4_1
	was used, the client determines the attributes		was used, the client determines the attributes
	used for the verifier by comparing attrset with		used for the verifier by comparing attrset with
	cva_attrs.attrmask; any bits set in the former but		cva_attrs.attrmask; any bits set in the former but
	not the latter identify the attributes used to store		not the latter identify the attributes used to store
	the verifier. The client MUST immediately send a		the verifier. The client <bcp14>MUST</bcp14> immediately send a
	SETATTR to set attributes used to store the verifier.		SETATTR to set attributes used to store the verifier.
	Until it does so, the attributes used to store the		Until it does so, the attributes used to store the
	verifier cannot be relied upon. The subsequent		verifier cannot be relied upon. The subsequent
	SETATTR MUST NOT occur in the same COMPOUND request		SETATTR <bcp14>MUST NOT</bcp14> occur in the same COMPOUND request
	as the OPEN.		as the OPEN.
	</t>		</t>
	<t>		<t>
	Unless a persistent session is used, use of the		Unless a persistent session is used, use of the
	GUARDED4 attribute does not provide exactly once		GUARDED4 attribute does not provide exactly once
	semantics. In particular, if a reply is lost and		semantics. In particular, if a reply is lost and
	the server does not detect the retransmission of the		the server does not detect the retransmission of the
	request, the operation can fail with NFS4ERR_EXIST,		request, the operation can fail with NFS4ERR_EXIST,
	even though the create was performed successfully.		even though the create was performed successfully.
	The client would use this behavior in the case that		The client would use this behavior in the case that
	the application has not requested an exclusive create		the application has not requested an exclusive create
	but has asked to have the file truncated when the		but has asked to have the file truncated when the
	file is opened. In the case of the client timing		file is opened. In the case of the client timing
	out and retransmitting the create request, the client		out and retransmitting the create request, the client
	can use GUARDED4 to prevent against a sequence like		can use GUARDED4 to prevent against a sequence like
	create, write, create (retransmitted) from occurring.		create, write, create (retransmitted) from occurring.
	</t>		</t>
	<t>		<t>
	For SHARE reservations, the value of the expression		For SHARE reservations, the value of the expression
	(share_access &amp; ~OPEN4_SHARE_ACCESS_WANT_DELEG_MASK) MUST be		(share_access &amp; ~OPEN4_SHARE_ACCESS_WANT_DELEG_MASK) <bcp14>MUST</bcp1 4> be
	one of OPEN4_SHARE_ACCESS_READ, OPEN4_SHARE_ACCESS_WRITE,		one of OPEN4_SHARE_ACCESS_READ, OPEN4_SHARE_ACCESS_WRITE,
	or OPEN4_SHARE_ACCESS_BOTH. If not, the server MUST		or OPEN4_SHARE_ACCESS_BOTH. If not, the server <bcp14>MUST</bcp14>
	return NFS4ERR_INVAL. The value of share_deny MUST		return NFS4ERR_INVAL. The value of share_deny <bcp14>MUST</bcp14>
	be one of OPEN4_SHARE_DENY_NONE, OPEN4_SHARE_DENY_READ,		be one of OPEN4_SHARE_DENY_NONE, OPEN4_SHARE_DENY_READ,
	OPEN4_SHARE_DENY_WRITE, or OPEN4_SHARE_DENY_BOTH. If not, the		OPEN4_SHARE_DENY_WRITE, or OPEN4_SHARE_DENY_BOTH. If not, the
	server MUST return NFS4ERR_INVAL.		server <bcp14>MUST</bcp14> return NFS4ERR_INVAL.
	</t>		</t>
	<t>		<t>
	Based on the share_access value (OPEN4_SHARE_ACCESS_READ,		Based on the share_access value (OPEN4_SHARE_ACCESS_READ,
	OPEN4_SHARE_ACCESS_WRITE, or OPEN4_SHARE_ACCESS_BOTH), the client		OPEN4_SHARE_ACCESS_WRITE, or OPEN4_SHARE_ACCESS_BOTH), the client
	should check that the requester has the proper access rights		should check that the requester has the proper access rights
	to perform the specified operation. This would generally be		to perform the specified operation. This would generally be
	the results of applying the ACL access rules to the file for the		the results of applying the ACL access rules to the file for the
	current requester. However, just as with the ACCESS operation, the		current requester. However, just as with the ACCESS operation, the
	client should not attempt to second-guess the server's decisions, as		client should not attempt to second-guess the server's decisions, as
	access rights may change and may be subject to server administrative		access rights may change and may be subject to server administrative
	controls outside the ACL framework. If the requester's READ or		controls outside the ACL framework. If the requester's READ or
	WRITE operation is not authorized (depending on the share_access		WRITE operation is not authorized (depending on the share_access
	value), the server MUST return NFS4ERR_ACCESS.		value), the server <bcp14>MUST</bcp14> return NFS4ERR_ACCESS.
	</t>
	<t>		</t>
			<t>
	Note that if the client ID was not created		Note that if the client ID was not created
	with the EXCHGID4_FLAG_BIND_PRINC_STATEID capability set in		with the EXCHGID4_FLAG_BIND_PRINC_STATEID capability set in
	the reply to EXCHANGE_ID, then the server MUST		the reply to EXCHANGE_ID, then the server <bcp14>MUST
	NOT impose any requirement that READs and WRITEs		NOT</bcp14> impose any requirement that READs and WRITEs
	sent for an open file have the same credentials		sent for an open file have the same credentials
	as the OPEN itself, and the server is REQUIRED to		as the OPEN itself, and the server is <bcp14>REQUIRED</bcp14> to
	perform access checking on the READs and WRITEs		perform access checking on the READs and WRITEs
	themselves. Otherwise, if the reply to EXCHANGE_ID		themselves. Otherwise, if the reply to EXCHANGE_ID
	did have EXCHGID4_FLAG_BIND_PRINC_STATEID set,		did have EXCHGID4_FLAG_BIND_PRINC_STATEID set,
	then with one exception, the credentials used in the OPEN request MUST		then with one exception, the credentials used in the OPEN request <bcp14>M UST</bcp14>
	match those used in the READs and WRITEs, and the		match those used in the READs and WRITEs, and the
	stateids in the READs and WRITEs MUST match, or be		stateids in the READs and WRITEs <bcp14>MUST</bcp14> match, or be
	derived from the stateid from the reply to OPEN.		derived from the stateid from the reply to OPEN.
	The exception is if SP4_SSV or SP4_MACH_CRED state		The exception is if SP4_SSV or SP4_MACH_CRED state
	protection is used, and the spo_must_allow		protection is used, and the spo_must_allow
	result of EXCHANGE_ID includes the READ and/or WRITE		result of EXCHANGE_ID includes the READ and/or WRITE
	operations. In that case, the machine or SSV		operations. In that case, the machine or SSV
	credential will be allowed to send READ and/or WRITE.		credential will be allowed to send READ and/or WRITE.
	See <xref target="OP_EXCHANGE_ID"/>.		See <xref target="OP_EXCHANGE_ID" format="default"/>.
	</t>		</t>
	<t>		<t>
	If the component provided to OPEN is a symbolic link, the error		If the component provided to OPEN is a symbolic link, the error
	NFS4ERR_SYMLINK will be returned to the client, while if it is		NFS4ERR_SYMLINK will be returned to the client, while if it is
	a directory the error NFS4ERR_ISDIR will be returned.		a directory the error NFS4ERR_ISDIR will be returned.
	If the component is neither		If the component is neither
	of those but not an ordinary file, the error NFS4ERR_WRONG_TYPE		of those but not an ordinary file, the error NFS4ERR_WRONG_TYPE
	is returned. If the current		is returned. If the current
	filehandle is not a directory, the error NFS4ERR_NOTDIR will be		filehandle is not a directory, the error NFS4ERR_NOTDIR will be
	returned.		returned.
	</t>		</t>
	<t>		<t>
	The use of the OPEN4_RESULT_PRESERVE_UNLINKED result flag allows		The use of the OPEN4_RESULT_PRESERVE_UNLINKED result flag allows
	a client to avoid the common implementation practice of renaming		a client to avoid the common implementation practice of renaming
	an open file to ".nfs&lt;unique value>" after it removes the file.		an open file to ".nfs&lt;unique value&gt;" after it removes the file.
	After the server returns OPEN4_RESULT_PRESERVE_UNLINKED, if a client		After the server returns OPEN4_RESULT_PRESERVE_UNLINKED, if a client
	sends a REMOVE operation that would reduce the file's link count to		sends a REMOVE operation that would reduce the file's link count to
	zero, the server SHOULD report a value		zero, the server <bcp14>SHOULD</bcp14> report a value
	of zero for the numlinks attribute on the file.		of zero for the numlinks attribute on the file.
	</t>		</t>
	<t>		<t>
	If another client has a delegation of the file being opened that		If another client has a delegation of the file being opened that
	conflicts with open being done (sometimes depending on the		conflicts with open being done (sometimes depending on the
	share_access or share_deny value specified),		share_access or share_deny value specified),
	the delegation(s) MUST be recalled, and the		the delegation(s) <bcp14>MUST</bcp14> be recalled, and the
	operation cannot proceed until each such delegation is returned		operation cannot proceed until each such delegation is returned
	or revoked. Except where this		or revoked. Except where this
	happens very quickly, one or more NFS4ERR_DELAY errors will be		happens very quickly, one or more NFS4ERR_DELAY errors will be
	returned to requests made while delegation remains outstanding.		returned to requests made while delegation remains outstanding.
	In the case of an OPEN_DELEGATE_WRITE delegation, any open by a different client		In the case of an OPEN_DELEGATE_WRITE delegation, any open by a different client
	will conflict, while for an OPEN_DELEGATE_READ delegation, only opens with one		will conflict, while for an OPEN_DELEGATE_READ delegation, only opens with one
	of the following characteristics will be considered conflicting:		of the following characteristics will be considered conflicting:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The value of share_access includes the bit		The value of share_access includes the bit
	OPEN4_SHARE_ACCESS_WRITE.		OPEN4_SHARE_ACCESS_WRITE.
	</t>		</li>
	<t>		<li>
	The value of share_deny specifies OPEN4_SHARE_DENY_READ or		The value of share_deny specifies OPEN4_SHARE_DENY_READ or
	OPEN4_SHARE_DENY_BOTH.		OPEN4_SHARE_DENY_BOTH.
	</t>		</li>
	<t>		<li>
	OPEN4_CREATE is specified together with UNCHECKED4, the		OPEN4_CREATE is specified together with UNCHECKED4, the
	size attribute is specified as zero (for truncation), and		size attribute is specified as zero (for truncation), and
	an existing file is truncated.		an existing file is truncated.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	If OPEN4_CREATE is specified and the file does not exist and		If OPEN4_CREATE is specified and the file does not exist and
	the current filehandle designates a directory for which another		the current filehandle designates a directory for which another
	client holds a directory delegation, then, unless the delegation		client holds a directory delegation, then, unless the delegation
	is such that the situation can be resolved by sending a notification,		is such that the situation can be resolved by sending a notification,
	the delegation MUST be recalled, and the operation cannot proceed		the delegation <bcp14>MUST</bcp14> be recalled, and the operation cannot p roceed
	until the delegation is returned or revoked. Except where this		until the delegation is returned or revoked. Except where this
	happens very quickly, one or more NFS4ERR_DELAY errors will be		happens very quickly, one or more NFS4ERR_DELAY errors will be
	returned to requests made while delegation remains outstanding.		returned to requests made while delegation remains outstanding.
	</t>		</t>
	<t>		<t>
	If OPEN4_CREATE is specified and the file does not exist and		If OPEN4_CREATE is specified and the file does not exist and
	the current filehandle designates a directory for which		the current filehandle designates a directory for which
	one or more directory delegations exist, then, when those delegations		one or more directory delegations exist, then, when those delegations
	request such notifications, NOTIFY4_ADD_ENTRY will be generated		request such notifications, NOTIFY4_ADD_ENTRY will be generated
	as a result of this operation.		as a result of this operation.
	</t>		</t>
	<section toc="exclude" anchor="open_getfh_issue"		<section toc="exclude" anchor="open_getfh_issue" numbered="true">
	title="Warning to Client Implementors">		<name>Warning to Client Implementors</name>
	<t>		<t>
	OPEN resembles LOOKUP in that it generates a filehandle for the client		OPEN resembles LOOKUP in that it generates a filehandle for the client
	to use. Unlike LOOKUP though, OPEN creates server state on the		to use. Unlike LOOKUP though, OPEN creates server state on the
	filehandle. In normal circumstances, the client can only release this		filehandle. In normal circumstances, the client can only release this
	state with a CLOSE operation. CLOSE uses the current filehandle to		state with a CLOSE operation. CLOSE uses the current filehandle to
	determine which file to close. Therefore, the client MUST follow every		determine which file to close. Therefore, the client <bcp14>MUST</bcp14> follow every
	OPEN operation with a GETFH operation in the same COMPOUND procedure.		OPEN operation with a GETFH operation in the same COMPOUND procedure.
	This will supply the client with the filehandle such that CLOSE can be		This will supply the client with the filehandle such that CLOSE can be
	used appropriately.		used appropriately.
	</t>		</t>
	<t>		<t>
	Simply waiting for the lease on the file to expire is insufficient		Simply waiting for the lease on the file to expire is insufficient
	because the server may maintain the state indefinitely as long as		because the server may maintain the state indefinitely as long as
	another client does not attempt to make a conflicting access to the		another client does not attempt to make a conflicting access to the
	same file.		same file.
	</t>		</t>
	<t>		<t>
	See also <xref target="COMPOUND_Sizing_Issues"/>.		See also <xref target="COMPOUND_Sizing_Issues" format="default"/>.
	</t>		</t>
	</section>		</section>
			</section>
	</section>		</section>
	</section>		<section anchor="OP_OPENATTR" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 19: OPENATTR - Open Named Attribute Directory</name>
	$ -->		<section toc="exclude" anchor="OP_OPENATTR_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The IETF Trust (2007) -->		<name>ARGUMENTS</name>
	<!-- Copyright (C) The Internet Society (2006) -->		<sourcecode type="xdr"><![CDATA[
	<section anchor="OP_OPENATTR" title="Operation 19: OPENATTR - Open Named Attribu
	te Directory" >
	<section toc="exclude" anchor="OP_OPENATTR_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct OPENATTR4args {		struct OPENATTR4args {
	/* CURRENT_FH: object */		/* CURRENT_FH: object */
	bool createdir;		bool createdir;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_OPENATTR_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_OPENATTR_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct OPENATTR4res {		struct OPENATTR4res {
	/*		/*
	* If status is NFS4_OK,		* If status is NFS4_OK,
	* new CURRENT_FH: named attribute		* new CURRENT_FH: named attribute
	* directory		* directory
	*/		*/
	nfsstat4 status;		nfsstat4 status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_OPENATTR_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_OPENATTR_DESCRIPTION" title="DESCRIPTION">
	<t>
	The OPENATTR operation is used to obtain the filehandle of the named		The OPENATTR operation is used to obtain the filehandle of the named
	attribute directory associated with the current filehandle. The		attribute directory associated with the current filehandle. The
	result of the OPENATTR will be a filehandle to an object of type		result of the OPENATTR will be a filehandle to an object of type
	NF4ATTRDIR. From this filehandle, READDIR and LOOKUP operations can		NF4ATTRDIR. From this filehandle, READDIR and LOOKUP operations can
	be used to obtain filehandles for the various named attributes		be used to obtain filehandles for the various named attributes
	associated with the original file system object. Filehandles returned		associated with the original file system object. Filehandles returned
	within the named attribute directory will designate objects of		within the named attribute directory will designate objects of
	type of NF4NAMEDATTR.		type of NF4NAMEDATTR.
	</t>		</t>
	<t>		<t>
	The createdir argument allows the client to signify if a named		The createdir argument allows the client to signify if a named
	attribute directory should be created as a result of the OPENATTR		attribute directory should be created as a result of the OPENATTR
	operation. Some clients may use the OPENATTR operation with a value		operation. Some clients may use the OPENATTR operation with a value
	of FALSE for createdir to determine if any named attributes exist for		of FALSE for createdir to determine if any named attributes exist for
	the object. If none exist, then NFS4ERR_NOENT will be returned. If		the object. If none exist, then NFS4ERR_NOENT will be returned. If
	createdir has a value of TRUE and no named attribute directory exists,		createdir has a value of TRUE and no named attribute directory exists,
	one is created and its filehandle becomes the current filehandle.		one is created and its filehandle becomes the current filehandle.
	On the other hand, if createdir has a value of TRUE and the named		On the other hand, if createdir has a value of TRUE and the named
	attribute directory already exists, no error results and the filehandle		attribute directory already exists, no error results and the filehandle
	of the existing directory becomes the current filehandle. The		of the existing directory becomes the current filehandle. The
	creation of a named attribute directory assumes		creation of a named attribute directory assumes
	that the server has implemented named attribute support in this		that the server has implemented named attribute support in this
	fashion and is not required to do so by this definition.		fashion and is not required to do so by this definition.
	</t>		</t>
	<t>		<t>
	If the current file handle designates an object of type		If the current filehandle designates an object of type
	NF4NAMEDATTR (a named attribute) or NF4ATTRDIR (a named attribute		NF4NAMEDATTR (a named attribute) or NF4ATTRDIR (a named attribute
	directory), an error of NFS4ERR_WRONG_TYPE is returned to the		directory), an error of NFS4ERR_WRONG_TYPE is returned to the
	client. Named attributes or a named attribute directory MUST NOT		client. Named attributes or a named attribute directory <bcp14>MUST NOT</ bcp14>
	have their own named attributes.		have their own named attributes.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_OPENATTR_IMPLEMENTATION" title="IMPLEMENTATI		<section toc="exclude" anchor="OP_OPENATTR_IMPLEMENTATION" numbered="tru
	ON">		e">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	If the server does not support named attributes for the current		If the server does not support named attributes for the current
	filehandle, an error of NFS4ERR_NOTSUPP will be returned to the		filehandle, an error of NFS4ERR_NOTSUPP will be returned to the
	client.		client.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_OPEN_DOWNGRADE" numbered="true" toc="default">
	$ -->		<name>Operation 21: OPEN_DOWNGRADE - Reduce Open File Access</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_OPEN_DOWNGRADE_ARGUMENTS" numbered="tr
	<!-- Copyright (C) The Internet Society (2006) -->		ue">
	<section anchor="OP_OPEN_DOWNGRADE" title="Operation 21: OPEN_DOWNGRADE - Reduce		<name>ARGUMENTS</name>
	Open File Access" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_OPEN_DOWNGRADE_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct OPEN_DOWNGRADE4args {		struct OPEN_DOWNGRADE4args {
	/* CURRENT_FH: opened file */		/* CURRENT_FH: opened file */
	stateid4 open_stateid;		stateid4 open_stateid;
	seqid4 seqid;		seqid4 seqid;
	uint32_t share_access;		uint32_t share_access;
	uint32_t share_deny;		uint32_t share_deny;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_OPEN_DOWNGRADE_RESULTS" numbered="true
	</figure>		">
	</section>		<name>RESULTS</name>
			<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_OPEN_DOWNGRADE_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct OPEN_DOWNGRADE4resok {		struct OPEN_DOWNGRADE4resok {
	stateid4 open_stateid;		stateid4 open_stateid;
	};		};
	union OPEN_DOWNGRADE4res switch(nfsstat4 status) {		union OPEN_DOWNGRADE4res switch(nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	OPEN_DOWNGRADE4resok resok4;		OPEN_DOWNGRADE4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_OPEN_DOWNGRADE_DESCRIPTION" numbered="
	</figure>		true">
	</section>		<name>DESCRIPTION</name>
			<t>
	<section toc="exclude" anchor="OP_OPEN_DOWNGRADE_DESCRIPTION" title="DESCRIPTI
	ON">
	<t>
	This operation is used to adjust the access and deny states		This operation is used to adjust the access and deny states
	for a given open. This is necessary when a given open-owner opens the		for a given open. This is necessary when a given open-owner opens the
	same file multiple times with different access and deny		same file multiple times with different access and deny
	values. In this situation, a close of one of the opens may change the		values. In this situation, a close of one of the opens may change the
	appropriate share_access and share_deny flags to remove bits		appropriate share_access and share_deny flags to remove bits
	associated with opens no longer in effect.		associated with opens no longer in effect.
	</t>		</t>
	<t>		<t>
	Valid values for the expression (share_access &amp;		Valid values for the expression (share_access &amp;
	~OPEN4_SHARE_ACCESS_WANT_DELEG_MASK) are OPEN4_SHARE_ACCESS_READ,		~OPEN4_SHARE_ACCESS_WANT_DELEG_MASK) are OPEN4_SHARE_ACCESS_READ,
	OPEN4_SHARE_ACCESS_WRITE, or OPEN4_SHARE_ACCESS_BOTH. If the client		OPEN4_SHARE_ACCESS_WRITE, or OPEN4_SHARE_ACCESS_BOTH. If the client
	specifies other values, the server MUST reply with NFS4ERR_INVAL.		specifies other values, the server <bcp14>MUST</bcp14> reply with NFS4ERR_
			INVAL.
	</t>
	<t>		</t>
			<t>
	Valid values for the share_deny field are		Valid values for the share_deny field are
	OPEN4_SHARE_DENY_NONE, OPEN4_SHARE_DENY_READ,		OPEN4_SHARE_DENY_NONE, OPEN4_SHARE_DENY_READ,
	OPEN4_SHARE_DENY_WRITE, or OPEN4_SHARE_DENY_BOTH. If		OPEN4_SHARE_DENY_WRITE, or OPEN4_SHARE_DENY_BOTH. If
	the client specifies other values, the server MUST		the client specifies other values, the server <bcp14>MUST</bcp14>
	reply with NFS4ERR_INVAL.		reply with NFS4ERR_INVAL.
	</t>		</t>
			<t>
	<t>
	After checking for valid values of share_access and		After checking for valid values of share_access and
	share_deny, the server replaces the current access		share_deny, the server replaces the current access
	and deny modes on the file with share_access and		and deny modes on the file with share_access and
	share_deny subject to the following constraints:		share_deny subject to the following constraints:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
	The bits in share_access SHOULD equal the union of the share_access		<li>
			The bits in share_access <bcp14>SHOULD</bcp14> equal the union of the sha
			re_access
	bits (not including OPEN4_SHARE_WANT_* bits)		bits (not including OPEN4_SHARE_WANT_* bits)
	specified for some subset of the OPENs		specified for some subset of the OPENs
	in effect for the current open-owner on the current		in effect for the current open-owner on the current
	file.		file.
	</t>		</li>
			<li>
	<t>		The bits in share_deny <bcp14>SHOULD</bcp14> equal the union of the
	The bits in share_deny SHOULD equal the union of the
	share_deny bits specified for some subset		share_deny bits specified for some subset
	of the OPENs in effect for the current open-owner		of the OPENs in effect for the current open-owner
	on the current file.		on the current file.
	</t>		</li>
	</list>		</ul>
			<t>
	If the above constraints are not respected,		If the above constraints are not respected,
	the server SHOULD return the error NFS4ERR_INVAL.		the server <bcp14>SHOULD</bcp14> return the error NFS4ERR_INVAL.
	Since share_access and share_deny bits should be		Since share_access and share_deny bits should be
	subsets of those already granted, short of a defect		subsets of those already granted, short of a defect
	in the client or server implementation, it is not		in the client or server implementation, it is not
	possible for the OPEN_DOWNGRADE request to be denied		possible for the OPEN_DOWNGRADE request to be denied
	because of conflicting share reservations.		because of conflicting share reservations.
	</t>		</t>
			<t>
	<t>		The seqid argument is not used in NFSv4.1, <bcp14>MAY</bcp14> be any value
	The seqid argument is not used in NFSv4.1, MAY be any value, and		, and
	MUST be ignored by the server.		<bcp14>MUST</bcp14> be ignored by the server.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_OPEN_DOWNGRADE_IMPLEMENTATION" title="IMPLEM		<section toc="exclude" anchor="OP_OPEN_DOWNGRADE_IMPLEMENTATION" numbere
	ENTATION">		d="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	An OPEN_DOWNGRADE operation may make OPEN_DELEGATE_READ delegations granta ble		An OPEN_DOWNGRADE operation may make OPEN_DELEGATE_READ delegations granta ble
	where they were not previously. Servers may choose to respond		where they were not previously. Servers may choose to respond
	immediately if there are pending delegation want requests or may		immediately if there are pending delegation want requests or may
	respond to the situation at a later time.		respond to the situation at a later time.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_PUTFH" numbered="true" toc="default">
	$ -->		<name>Operation 22: PUTFH - Set Current Filehandle</name>
	<!-- Copyright (C) The IETF Trust (2007) -->		<section toc="exclude" anchor="OP_PUTFH_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_PUTFH" title="Operation 22: PUTFH - Set Current Filehandle"		<sourcecode type="xdr"><![CDATA[
	>
	<section toc="exclude" anchor="OP_PUTFH_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct PUTFH4args {		struct PUTFH4args {
	nfs_fh4 object;		nfs_fh4 object;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_PUTFH_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_PUTFH_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct PUTFH4res {		struct PUTFH4res {
	/*		/*
	* If status is NFS4_OK,		* If status is NFS4_OK,
	* new CURRENT_FH: argument to PUTFH		* new CURRENT_FH: argument to PUTFH
	*/		*/
	nfsstat4 status;		nfsstat4 status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_PUTFH_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_PUTFH_DESCRIPTION" title="DESCRIPTION">
	<t>
	This operation replaces the current filehandle with the filehandle provide d as an		This operation replaces the current filehandle with the filehandle provide d as an
	argument. It clears the current stateid.		argument. It clears the current stateid.
	</t>		</t>
	<t>		<t>
	If the security mechanism used by the requester does not meet the		If the security mechanism used by the requester does not meet the
	requirements of the filehandle provided to this operation, the server		requirements of the filehandle provided to this operation, the server
	MUST return NFS4ERR_WRONGSEC.		<bcp14>MUST</bcp14> return NFS4ERR_WRONGSEC.
	</t>		</t>
	<t>		<t>
	See <xref target="current_filehandle"/> for more details on the		See <xref target="current_filehandle" format="default"/> for more details
			on the
	current filehandle.		current filehandle.
	</t>		</t>
	<t>		<t>
	See <xref target="current_stateid"/> for more details on the current		See <xref target="current_stateid" format="default"/> for more details on
			the current
	stateid.		stateid.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_PUTFH_IMPLEMENTATION" title="IMPLEMENTATION"		<section toc="exclude" anchor="OP_PUTFH_IMPLEMENTATION" numbered="true">
	>		<name>IMPLEMENTATION</name>
	<t>		<t>
	This operation is used		This operation is used
	in an NFS request to set the context for file accessing operations that		in an NFS request to set the context for file accessing operations that
	follow in the same COMPOUND request.		follow in the same COMPOUND request.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_PUTPUBFH" numbered="true" toc="default">
	$ -->		<name>Operation 23: PUTPUBFH - Set Public Filehandle</name>
	<!-- Copyright (C) The IETF Trust (2007) -->		<section toc="exclude" anchor="OP_PUTPUBFH_ARGUMENT" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_PUTPUBFH" title="Operation 23: PUTPUBFH - Set		<sourcecode type="xdr"><![CDATA[
	Public Filehandle" >
	<section toc="exclude" anchor="OP_PUTPUBFH_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	void;		void;
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_PUTPUBFH_RESULT" numbered="true">
	<section toc="exclude" anchor="OP_PUTPUBFH_RESULT" title="RESULT">		<name>RESULT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct PUTPUBFH4res {		struct PUTPUBFH4res {
	/*		/*
	* If status is NFS4_OK,		* If status is NFS4_OK,
	* new CURRENT_FH: public fh		* new CURRENT_FH: public fh
	*/		*/
	nfsstat4 status;		nfsstat4 status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_PUTPUBFH_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_PUTPUBFH_DESCRIPTION" title="DESCRIPTION">
	<t>
	This operation replaces the current filehandle with the filehandle that		This operation replaces the current filehandle with the filehandle that
	represents the public filehandle of the server's namespace.		represents the public filehandle of the server's namespace.
	This filehandle may be different from the "root" filehandle		This filehandle may be different from the "root" filehandle
	that may be associated with some other directory on the server.		that may be associated with some other directory on the server.
	</t>		</t>
	<t>		<t>
	PUTPUBFH also clears the current stateid.		PUTPUBFH also clears the current stateid.
	</t>		</t>
	<t>		<t>
	The public filehandle represents the concepts embodied in <xref		The public filehandle represents the concepts embodied in <xref target="RF
	target="RFC2054">RFC 2054</xref>, <xref		C2054" format="default">RFC 2054</xref>, <xref target="RFC2055" format="default"
	target="RFC2055">RFC 2055</xref>, and <xref		>RFC 2055</xref>, and <xref target="RFC2224" format="default">RFC 2224</xref>.
	target="RFC2224">RFC 2224</xref>. The intent for NFSv4.1		The intent for NFSv4.1
	is that the public filehandle (represented by the PUTPUBFH		is that the public filehandle (represented by the PUTPUBFH
	operation) be used as a method of providing WebNFS server		operation) be used as a method of providing WebNFS server
	compatibility with NFSv3.		compatibility with NFSv3.
	</t>		</t>
	<t>		<t>
	The public filehandle and the root filehandle (represented by the		The public filehandle and the root filehandle (represented by the
	PUTROOTFH operation) SHOULD be equivalent. If the public and root		PUTROOTFH operation) <bcp14>SHOULD</bcp14> be equivalent. If the public a
	filehandles are not equivalent, then the directory corresponding to the pu		nd root
	blic filehandle MUST be a		filehandles are not equivalent, then the directory corresponding to the pu
			blic filehandle <bcp14>MUST</bcp14> be a
	descendant of the directory corresponding to the root filehandle.		descendant of the directory corresponding to the root filehandle.
	</t>		</t>
	<t>		<t>
	See <xref target="current_filehandle"/> for more details on the		See <xref target="current_filehandle" format="default"/> for more details
			on the
	current filehandle.		current filehandle.
	</t>		</t>
	<t>		<t>
	See <xref target="current_stateid"/> for more details on the current		See <xref target="current_stateid" format="default"/> for more details on
			the current
	stateid.		stateid.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_PUTPUBFH_IMPLEMENTATION" title="IMPLEMENTATI		<section toc="exclude" anchor="OP_PUTPUBFH_IMPLEMENTATION" numbered="tru
	ON">		e">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	This operation is used		This operation is used
	in an NFS request to set the context for file accessing operations that		in an NFS request to set the context for file accessing operations that
	follow in the same COMPOUND request.		follow in the same COMPOUND request.
	</t>		</t>
	<t>		<t>
	With the NFSv3 public filehandle, the client is		With the NFSv3 public filehandle, the client is
	able to specify whether the pathname provided in the LOOKUP		able to specify whether the pathname provided in the LOOKUP
	should be evaluated as either an absolute path relative to the		should be evaluated as either an absolute path relative to the
	server's root or relative to the public filehandle. <xref		server's root or relative to the public filehandle. <xref target="RFC2224
	target="RFC2224">RFC 2224</xref> contains further discussion of		" format="default">RFC 2224</xref> contains further discussion of
	the functionality. With NFSv4.1, that type of		the functionality. With NFSv4.1, that type of
	specification is not directly available in the LOOKUP operation.		specification is not directly available in the LOOKUP operation.
	The reason for this is because the component separators needed		The reason for this is because the component separators needed
	to specify absolute vs. relative are not allowed in NFSv4. Therefore, the client is responsible for constructing its		to specify absolute vs. relative are not allowed in NFSv4. Therefore, the client is responsible for constructing its
	request such that the use of either PUTROOTFH or PUTPUBFH		request such that the use of either PUTROOTFH or PUTPUBFH
	signifies absolute or relative evaluation of an NFS URL,		signifies absolute or relative evaluation of an NFS URL,
	respectively.		respectively.
	</t>		</t>
	<t>		<t>
	Note that there are warnings mentioned in <xref		Note that there are warnings mentioned in <xref target="RFC2224" format="d
	target="RFC2224">RFC 2224</xref> with respect to the use of		efault">RFC 2224</xref> with respect to the use of
	absolute evaluation and the restrictions the server may place on		absolute evaluation and the restrictions the server may place on
	that evaluation with respect to how much of its namespace has		that evaluation with respect to how much of its namespace has
	been made available. These same warnings apply to NFSv4.1. It is likely, therefore, that because of server		been made available. These same warnings apply to NFSv4.1. It is likely, therefore, that because of server
	implementation details, an NFSv3 absolute public		implementation details, an NFSv3 absolute public
	filehandle look up may behave differently than an NFSv4.1		filehandle look up may behave differently than an NFSv4.1
	absolute resolution.		absolute resolution.
	</t>		</t>
	<t>		<t>
	There is a form of security negotiation as described		There is a form of security negotiation as described
	in <xref target="RFC2755">RFC 2755</xref> that uses		in <xref target="RFC2755" format="default">RFC 2755</xref> that uses
	the public filehandle and an overloading of the pathname.		the public filehandle and an overloading of the pathname.
	This method is not available with NFSv4.1 as		This method is not available with NFSv4.1 as
	filehandles are not overloaded with special		filehandles are not overloaded with special
	meaning and therefore do not provide the same		meaning and therefore do not provide the same
	framework as NFSv3. Clients should therefore use		framework as NFSv3. Clients should therefore use
	the security negotiation mechanisms described in		the security negotiation mechanisms described in
	<xref target="Security_Service_Negotiation" />.		<xref target="Security_Service_Negotiation" format="default"/>.
	</t>
	</section>
	</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->
	<!-- Copyright (C) The IETF Trust (2007) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="OP_PUTROOTFH" title="Operation 24: PUTROOTFH - Set Root Filehan
	dle" >
	<section toc="exclude" anchor="OP_PUTROOTFH_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	void;
	</artwork>
	</figure>
	</section>
	<section toc="exclude" anchor="OP_PUTROOTFH_RESULTS" title="RESULTS">		</t>
	<figure>		</section>
	<artwork>		</section>
			<section anchor="OP_PUTROOTFH" numbered="true" toc="default">
			<name>Operation 24: PUTROOTFH - Set Root Filehandle</name>
			<section toc="exclude" anchor="OP_PUTROOTFH_ARGUMENTS" numbered="true">
			<name>ARGUMENTS</name>
			<sourcecode type="xdr"><![CDATA[
			void;]]></sourcecode>
			</section>
			<section toc="exclude" anchor="OP_PUTROOTFH_RESULTS" numbered="true">
			<name>RESULTS</name>
			<sourcecode type="xdr"><![CDATA[
	struct PUTROOTFH4res {		struct PUTROOTFH4res {
	/*		/*
	* If status is NFS4_OK,		* If status is NFS4_OK,
	* new CURRENT_FH: root fh		* new CURRENT_FH: root fh
	*/		*/
	nfsstat4 status;		nfsstat4 status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_PUTROOTFH_DESCRIPTION" numbered="true"
	</figure>		>
	</section>		<name>DESCRIPTION</name>
			<t>
	<section toc="exclude" anchor="OP_PUTROOTFH_DESCRIPTION" title="DESCRIPTION">
	<t>
	This operation replaces the current filehandle with the filehandle that re presents		This operation replaces the current filehandle with the filehandle that re presents
	the root of the server's namespace. From this filehandle, a LOOKUP		the root of the server's namespace. From this filehandle, a LOOKUP
	operation can locate any other filehandle on the server. This		operation can locate any other filehandle on the server. This
	filehandle may be different from the "public" filehandle that may be		filehandle may be different from the "public" filehandle that may be
	associated with some other directory on the server.		associated with some other directory on the server.
	</t>		</t>
	<t>		<t>
	PUTROOTFH also clears the current stateid.		PUTROOTFH also clears the current stateid.
	</t>		</t>
	<t>		<t>
	See <xref target="current_filehandle"/> for more details on the		See <xref target="current_filehandle" format="default"/> for more details
			on the
	current filehandle.		current filehandle.
	</t>		</t>
	<t>		<t>
	See <xref target="current_stateid"/> for more details on the current		See <xref target="current_stateid" format="default"/> for more details on
			the current
	stateid.		stateid.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_PUTROOTFH_IMPLEMENTATION" title="IMPLEMENTAT		<section toc="exclude" anchor="OP_PUTROOTFH_IMPLEMENTATION" numbered="tr
	ION">		ue">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	This operation is used		This operation is used
	in an NFS request to set the context for file accessing operations that		in an NFS request to set the context for file accessing operations that
	follow in the same COMPOUND request.		follow in the same COMPOUND request.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_READ" numbered="true" toc="default">
	$ -->		<name>Operation 25: READ - Read from File</name>
	<!-- Copyright (C) The IETF Trust (2007) -->		<section toc="exclude" anchor="OP_READ_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_READ" title="Operation 25: READ - Read from File" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_READ_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct READ4args {		struct READ4args {
	/* CURRENT_FH: file */		/* CURRENT_FH: file */
	stateid4 stateid;		stateid4 stateid;
	offset4 offset;		offset4 offset;
	count4 count;		count4 count;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_READ_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_READ_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct READ4resok {		struct READ4resok {
	bool eof;		bool eof;
	opaque data&lt;>;		opaque data<>;
	};		};
	union READ4res switch (nfsstat4 status) {		union READ4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	READ4resok resok4;		READ4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_READ_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_READ_DESCRIPTION" title="DESCRIPTION">
	<t>
	The READ operation reads data from the regular file identified by the		The READ operation reads data from the regular file identified by the
	current filehandle.		current filehandle.
	</t>		</t>
	<t>		<t>
	The client provides an offset of where the READ is to start and a		The client provides an offset of where the READ is to start and a
	count of how many bytes are to be read. An offset of zero means		count of how many bytes are to be read. An offset of zero means
	to read data starting at the beginning of the file. If offset is		to read data starting at the beginning of the file. If offset is
	greater than or equal to the size of the file, the status NFS4_OK is		greater than or equal to the size of the file, the status NFS4_OK is
	returned with a data length set to zero and eof is set to TRUE.		returned with a data length set to zero and eof is set to TRUE.
	The READ is subject to access permissions checking.		The READ is subject to access permissions checking.
	</t>		</t>
	<t>		<t>
	If the client specifies a count value of zero, the READ succeeds		If the client specifies a count value of zero, the READ succeeds
	and returns zero bytes of data again subject to access permissions		and returns zero bytes of data again subject to access permissions
	checking. The server may choose to return fewer bytes than specified		checking. The server may choose to return fewer bytes than specified
	by the client. The client needs to check for this condition and		by the client. The client needs to check for this condition and
	handle the condition appropriately.		handle the condition appropriately.
	</t>		</t>
	<t>		<t>
	Except when special stateids are used, the		Except when special stateids are used, the
	stateid value for a READ request represents a value returned from		stateid value for a READ request represents a value returned from
	a previous byte-range lock or share reservation request or the stateid		a previous byte-range lock or share reservation request or the stateid
	associated with a delegation. The stateid identifies the associated		associated with a delegation. The stateid identifies the associated
	owners if any and is		owners if any and is
	used by the server to verify that the associated locks are still		used by the server to verify that the associated locks are still
	valid (e.g., have not been revoked).		valid (e.g., have not been revoked).
	</t>		</t>
	<t>		<t>
	If the read ended at the end-of-file (formally, in a correctly formed		If the read ended at the end-of-file (formally, in a correctly formed
	READ operation, if offset + count is equal to the size of the file), or		READ operation, if offset + count is equal to the size of the file), or
	the READ operation extends beyond the size of the file (if offset +		the READ operation extends beyond the size of the file (if offset +
	count is greater than the size of the file), eof is returned as TRUE;		count is greater than the size of the file), eof is returned as TRUE;
	otherwise, it is FALSE. A successful READ of an empty file will always		otherwise, it is FALSE. A successful READ of an empty file will always
	return eof as TRUE.		return eof as TRUE.
	</t>		</t>
	<t>		<t>
	If the current filehandle is not an ordinary file, an error will be		If the current filehandle is not an ordinary file, an error will be
	returned to the client. In the case that the current filehandle		returned to the client. In the case that the current filehandle
	represents an object of type NF4DIR, NFS4ERR_ISDIR is returned.		represents an object of type NF4DIR, NFS4ERR_ISDIR is returned.
	If the current filehandle designates a symbolic link,		If the current filehandle designates a symbolic link,
	NFS4ERR_SYMLINK is returned. In all other cases,		NFS4ERR_SYMLINK is returned. In all other cases,
	NFS4ERR_WRONG_TYPE is returned.		NFS4ERR_WRONG_TYPE is returned.
	</t>		</t>
	<t>		<t>
	For a READ with a stateid value of all bits equal to zero, the server MAY		For a READ with a stateid value of all bits equal to zero, the server <bcp
	allow		14>MAY</bcp14> allow
	the READ to be serviced subject to mandatory byte-range locks or the curre nt		the READ to be serviced subject to mandatory byte-range locks or the curre nt
	share deny modes for the file. For a READ with a stateid value of all		share deny modes for the file. For a READ with a stateid value of all
	bits equal to one, the server MAY allow READ operations to bypass locking checks		bits equal to one, the server <bcp14>MAY</bcp14> allow READ operations to bypass locking checks
	at the server.		at the server.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_READ_IMPLEMENTATION" title="IMPLEMENTATION">		<section toc="exclude" anchor="OP_READ_IMPLEMENTATION" numbered="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	If the server returns a "short read" (i.e., fewer data than requested and eof is set to FALSE), the client should send another READ to get the		If the server returns a "short read" (i.e., fewer data than requested and eof is set to FALSE), the client should send another READ to get the
	remaining data. A server may return less data than requested under		remaining data. A server may return less data than requested under
	several circumstances. The file may have been truncated by another		several circumstances. The file may have been truncated by another
	client or perhaps on the server itself, changing the file size from		client or perhaps on the server itself, changing the file size from
	what the requesting client believes to be the case. This would reduce		what the requesting client believes to be the case. This would reduce
	the actual amount of data available to the client. It is possible		the actual amount of data available to the client. It is possible
	that the server reduce the transfer size and so return a short		that the server reduce the transfer size and so return a short
	read result. Server resource exhaustion may also occur in a		read result. Server resource exhaustion may also occur in a
	short read.		short read.
	</t>		</t>
	<t>		<t>
	If mandatory byte-range locking is in effect for the file, and if the byte -range		If mandatory byte-range locking is in effect for the file, and if the byte -range
	corresponding to the data to be read from the file is WRITE_LT locked by a n		corresponding to the data to be read from the file is WRITE_LT locked by a n
	owner not associated with the stateid, the server will return the		owner not associated with the stateid, the server will return the
	NFS4ERR_LOCKED error. The client should try to get the appropriate		NFS4ERR_LOCKED error. The client should try to get the appropriate
	READ_LT via the LOCK operation before re-attempting the		READ_LT via the LOCK operation before re-attempting the
	READ. When the READ completes, the client should release the byte-range		READ. When the READ completes, the client should release the byte-range
	lock via LOCKU.		lock via LOCKU.
	</t>		</t>
	<t>		<t>
	If another client has an OPEN_DELEGATE_WRITE delegation for the file being read,		If another client has an OPEN_DELEGATE_WRITE delegation for the file being read,
	the delegation must be recalled, and the		the delegation must be recalled, and the
	operation cannot proceed until that delegation is returned		operation cannot proceed until that delegation is returned
	or revoked. Except where this		or revoked. Except where this
	happens very quickly, one or more NFS4ERR_DELAY errors will be		happens very quickly, one or more NFS4ERR_DELAY errors will be
	returned to requests made while the delegation remains outstanding.		returned to requests made while the delegation remains outstanding.
	Normally, delegations will not be recalled as a result of a READ		Normally, delegations will not be recalled as a result of a READ
	operation since the recall will occur as a result of an earlier		operation since the recall will occur as a result of an earlier
	OPEN. However, since it is possible for a READ to be done with		OPEN. However, since it is possible for a READ to be done with
	a special stateid, the server needs to check for this case even		a special stateid, the server needs to check for this case even
	though the client should have done an OPEN previously.		though the client should have done an OPEN previously.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_READDIR" numbered="true" toc="default">
	$ -->		<name>Operation 26: READDIR - Read Directory</name>
	<!-- Copyright (C) The IETF Trust (2007) -->		<section toc="exclude" anchor="OP_READDIR_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_READDIR" title="Operation 26: READDIR - Read Directory" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_READDIR_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct READDIR4args {		struct READDIR4args {
	/* CURRENT_FH: directory */		/* CURRENT_FH: directory */
	nfs_cookie4 cookie;		nfs_cookie4 cookie;
	verifier4 cookieverf;		verifier4 cookieverf;
	count4 dircount;		count4 dircount;
	count4 maxcount;		count4 maxcount;
	bitmap4 attr_request;		bitmap4 attr_request;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_READDIR_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_READDIR_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct entry4 {		struct entry4 {
	nfs_cookie4 cookie;		nfs_cookie4 cookie;
	component4 name;		component4 name;
	fattr4 attrs;		fattr4 attrs;
	entry4 *nextentry;		entry4 *nextentry;
	};		};
	struct dirlist4 {		struct dirlist4 {
	entry4 *entries;		entry4 *entries;
	bool eof;		bool eof;
	skipping to change at line 33295 ¶		skipping to change at line 33522 ¶
	struct READDIR4resok {		struct READDIR4resok {
	verifier4 cookieverf;		verifier4 cookieverf;
	dirlist4 reply;		dirlist4 reply;
	};		};
	union READDIR4res switch (nfsstat4 status) {		union READDIR4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	READDIR4resok resok4;		READDIR4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_READDIR_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_READDIR_DESCRIPTION" title="DESCRIPTION">
	<t>
	The READDIR operation retrieves a variable number of entries from a		The READDIR operation retrieves a variable number of entries from a
	file system directory and returns client-requested attributes for each		file system directory and returns client-requested attributes for each
	entry along with information to allow the client to request additional		entry along with information to allow the client to request additional
	directory entries in a subsequent READDIR.		directory entries in a subsequent READDIR.
	</t>		</t>
	<t>		<t>
	The arguments contain a cookie value that represents where the READDIR		The arguments contain a cookie value that represents where the READDIR
	should start within the directory. A value of zero for the cookie		should start within the directory. A value of zero for the cookie
	is used to start reading at the beginning of the directory. For		is used to start reading at the beginning of the directory. For
	subsequent READDIR requests, the client specifies a cookie value that		subsequent READDIR requests, the client specifies a cookie value that
	is provided by the server on a previous READDIR request.		is provided by the server on a previous READDIR request.
	</t>		</t>
	<t>		<t>
	The request's cookieverf field should be set to 0		The request's cookieverf field should be set to 0
	zero) when the request's cookie field is zero		zero) when the request's cookie field is zero
	(first read of the directory). On subsequent requests, the		(first read of the directory). On subsequent requests, the
	cookieverf field must match the cookieverf returned		cookieverf field must match the cookieverf returned
	by the READDIR in which the cookie was acquired.		by the READDIR in which the cookie was acquired.
	If the server determines that the cookieverf		If the server determines that the cookieverf
	is no longer valid for the directory, the error		is no longer valid for the directory, the error
	NFS4ERR_NOT_SAME must be returned.		NFS4ERR_NOT_SAME must be returned.
	</t>		</t>
	<t>		<t>
	The dircount field of the request is a hint of the maximum number		The dircount field of the request is a hint of the maximum number
	of bytes of directory information that should be returned. This value		of bytes of directory information that should be returned. This value
	represents the total length of the names of the directory entries and the		represents the total length of the names of the directory entries and the
	cookie value for these entries. This length represents the XDR		cookie value for these entries. This length represents the XDR
	encoding of the data (names and cookies) and not the length in the		encoding of the data (names and cookies) and not the length in the
	native format of the server.		native format of the server.
	</t>		</t>
	<t>		<t>
	The maxcount field of the request represents the maximum		The maxcount field of the request represents the maximum
	total size of all of the data being returned within		total size of all of the data being returned within
	the READDIR4resok structure and includes the XDR		the READDIR4resok structure and includes the XDR
	overhead. The server MAY return less data. If the		overhead. The server <bcp14>MAY</bcp14> return less data. If the
	server is unable to return a single directory entry		server is unable to return a single directory entry
	within the maxcount limit, the error NFS4ERR_TOOSMALL		within the maxcount limit, the error NFS4ERR_TOOSMALL
	MUST be returned to the client.		<bcp14>MUST</bcp14> be returned to the client.
	</t>		</t>
	<t>		<t>
	Finally, the request's attr_request field represents		Finally, the request's attr_request field represents
	the list of attributes to be returned for each		the list of attributes to be returned for each
	directory entry supplied by the server.		directory entry supplied by the server.
	</t>		</t>
	<t>		<t>
	A successful reply consists of a list of		A successful reply consists of a list of
	directory entries. Each of these entries contains the name of the		directory entries. Each of these entries contains the name of the
	directory entry, a cookie value for that entry, and the associated		directory entry, a cookie value for that entry, and the associated
	attributes as requested. The "eof" flag has a value of TRUE if there		attributes as requested. The "eof" flag has a value of TRUE if there
	are no more entries in the directory.		are no more entries in the directory.
	</t>		</t>
	<t>		<t>
	The cookie value is only meaningful to the server and is used		The cookie value is only meaningful to the server and is used
	as a cursor for the directory entry. As mentioned, this cookie		as a cursor for the directory entry. As mentioned, this cookie
	is used by the client for subsequent READDIR operations so that it may		is used by the client for subsequent READDIR operations so that it may
	continue reading a directory. The cookie is similar in concept to a		continue reading a directory. The cookie is similar in concept to a
	READ offset but MUST NOT be interpreted as such by the client.		READ offset but <bcp14>MUST NOT</bcp14> be interpreted as such by the clie
	Ideally, the cookie value SHOULD NOT change if the directory is		nt.
			Ideally, the cookie value <bcp14>SHOULD NOT</bcp14> change if the director
			y is
	modified since the client may be caching these values.		modified since the client may be caching these values.
	</t>		</t>
	<t>		<t>
	In some cases, the server may encounter an error while obtaining the		In some cases, the server may encounter an error while obtaining the
	attributes for a directory entry. Instead of returning an error for		attributes for a directory entry. Instead of returning an error for
	the entire READDIR operation, the server can instead return the		the entire READDIR operation, the server can instead return the
	attribute rdattr_error (<xref target="attrdef_rdattr_error"/>). With this , the server is able to		attribute rdattr_error (<xref target="attrdef_rdattr_error" format="defaul t"/>). With this, the server is able to
	communicate the failure to the client and not fail the entire		communicate the failure to the client and not fail the entire
	operation in the instance of what might be a transient failure.		operation in the instance of what might be a transient failure.
	Obviously, the client must request the fattr4_rdattr_error attribute		Obviously, the client must request the fattr4_rdattr_error attribute
	for this method to work properly. If the client does not request the		for this method to work properly. If the client does not request the
	attribute, the server has no choice but to return failure for the		attribute, the server has no choice but to return failure for the
	entire READDIR operation.		entire READDIR operation.
	</t>		</t>
	<t>		<t>
	For some file system environments, the directory entries "." and ".."		For some file system environments, the directory entries "." and ".."
	have special meaning, and in other environments, they do not. If the		have special meaning, and in other environments, they do not. If the
	server supports these special entries within a directory, they SHOULD		server supports these special entries within a directory, they <bcp14>SHOU
	NOT be returned to the client as part of the READDIR response. To		LD
			NOT</bcp14> be returned to the client as part of the READDIR response. To
	enable some client environments, the cookie values of zero, 1, and 2 are		enable some client environments, the cookie values of zero, 1, and 2 are
	to be considered reserved. Note that the UNIX client will use these		to be considered reserved. Note that the UNIX client will use these
	values when combining the server's response and local representations		values when combining the server's response and local representations
	to enable a fully formed UNIX directory presentation to the		to enable a fully formed UNIX directory presentation to the
	application.		application.
	</t>		</t>
	<t>		<t>
	For READDIR arguments, cookie values of one and two SHOULD NOT be used, an		For READDIR arguments, cookie values of one and two <bcp14>SHOULD NOT</bcp
	d		14> be used, and
	for READDIR results, cookie values of zero, one, and two SHOULD NOT be		for READDIR results, cookie values of zero, one, and two <bcp14>SHOULD NOT
			</bcp14> be
	returned.		returned.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_READDIR_IMPLEMENTATION" title="IMPLEMENTATIO		<section toc="exclude" anchor="OP_READDIR_IMPLEMENTATION" numbered="true
	N">		">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	The server's file system directory representations		The server's file system directory representations
	can differ greatly. A client's programming		can differ greatly. A client's programming
	interfaces may also be bound to the local operating		interfaces may also be bound to the local operating
	environment in a way that does not translate well		environment in a way that does not translate well
	into the NFS protocol. Therefore, the use of the		into the NFS protocol. Therefore, the use of the
	dircount and maxcount fields are provided to enable		dircount and maxcount fields are provided to enable
	the client to provide hints to the server. If the		the client to provide hints to the server. If the
	client is aggressive about attribute collection		client is aggressive about attribute collection
	during a READDIR, the server has an idea of how to		during a READDIR, the server has an idea of how to
	limit the encoded response.		limit the encoded response.
	</t>		</t>
	<t>		<t>
	If dircount is zero, the server bounds the reply's		If dircount is zero, the server bounds the reply's
	size based on the request's maxcount field.		size based on the request's maxcount field.
	</t>		</t>
	<t>		<t>
	The cookieverf may be used by the server to help manage cookie values		The cookieverf may be used by the server to help manage cookie values
	that may become stale. It should be a rare occurrence that a server is		that may become stale. It should be a rare occurrence that a server is
	unable to continue properly reading a directory with the provided		unable to continue properly reading a directory with the provided
	cookie/cookieverf pair. The server SHOULD make every effort to avoid		cookie/cookieverf pair. The server <bcp14>SHOULD</bcp14> make every effor t to avoid
	this condition since the application at the client might be unable to		this condition since the application at the client might be unable to
	properly handle this type of failure.		properly handle this type of failure.
	</t>		</t>
	<t>		<t>
	The use of the cookieverf will also protect the client from using		The use of the cookieverf will also protect the client from using
	READDIR cookie values that might be stale. For example, if the file		READDIR cookie values that might be stale. For example, if the file
	system has been migrated, the server might or might not be able to use the		system has been migrated, the server might or might not be able to use the
	same cookie values to service READDIR as the previous server used.		same cookie values to service READDIR as the previous server used.
	With the client providing the cookieverf, the server is able to		With the client providing the cookieverf, the server is able to
	provide the appropriate response to the client. This prevents the		provide the appropriate response to the client. This prevents the
	case where the server accepts a cookie value but the underlying		case where the server accepts a cookie value but the underlying
	directory has changed and the response is invalid from the client's		directory has changed and the response is invalid from the client's
	context of its previous READDIR.		context of its previous READDIR.
	</t>		</t>
	<t>		<t>
	Since some servers will not be returning "." and ".." entries as has		Since some servers will not be returning "." and ".." entries as has
	been done with previous versions of the NFS protocol, the client that		been done with previous versions of the NFS protocol, the client that
	requires these entries be present in READDIR responses must fabricate		requires these entries be present in READDIR responses must fabricate
	them.		them.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_READLINK" numbered="true" toc="default">
	$ -->		<name>Operation 27: READLINK - Read Symbolic Link</name>
	<!-- Copyright (C) The IETF Trust (2007) -->		<section toc="exclude" anchor="OP_READLINK_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_READLINK" title="Operation 27: READLINK - Read Symbolic Link		<sourcecode type="xdr"><![CDATA[
	" >
	<section toc="exclude" anchor="OP_READLINK_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	/* CURRENT_FH: symlink */		/* CURRENT_FH: symlink */
	void;		void;]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_READLINK_RESULTS" numbered="true">
	</section>		<name>RESULTS</name>
			<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_READLINK_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct READLINK4resok {		struct READLINK4resok {
	linktext4 link;		linktext4 link;
	};		};
	union READLINK4res switch (nfsstat4 status) {		union READLINK4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	READLINK4resok resok4;		READLINK4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_READLINK_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_READLINK_DESCRIPTION" title="DESCRIPTION">
	<t>
	READLINK reads the data associated with a symbolic		READLINK reads the data associated with a symbolic
	link. Depending on the value of the UTF-8 capability		link. Depending on the value of the UTF-8 capability
	attribute (<xref target="utf8_caps"/>), the data is encoded		attribute (<xref target="utf8_caps" format="default"/>), the data is encod ed
	in UTF-8.		in UTF-8.
	Whether created by an NFS client or created locally		Whether created by an NFS client or created locally
	on the server, the data in a symbolic link is not		on the server, the data in a symbolic link is not
	interpreted (except possibly to check for proper UTF-8		interpreted (except possibly to check for proper UTF-8
	encoding) when created, but is simply stored.		encoding) when created, but is simply stored.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_READLINK_IMPLEMENTATION" title="IMPLEMENTATI		<section toc="exclude" anchor="OP_READLINK_IMPLEMENTATION" numbered="tru
	ON">		e">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	A symbolic link is nominally a pointer to another file. The data is		A symbolic link is nominally a pointer to another file. The data is
	not necessarily interpreted by the server, just stored in the file.		not necessarily interpreted by the server, just stored in the file.
	It is possible for a client implementation to store a pathname that		It is possible for a client implementation to store a pathname that
	is not meaningful to the server operating system in a symbolic link.		is not meaningful to the server operating system in a symbolic link.
	A READLINK operation returns the data to the client for		A READLINK operation returns the data to the client for
	interpretation. If different implementations want to share access to		interpretation. If different implementations want to share access to
	symbolic links, then they must agree on the interpretation of the data		symbolic links, then they must agree on the interpretation of the data
	in the symbolic link.		in the symbolic link.
	</t>		</t>
	<t>		<t>
	The READLINK operation is only allowed on objects of type NF4LNK.		The READLINK operation is only allowed on objects of type NF4LNK.
	The server should return the error NFS4ERR_WRONG_TYPE if the		The server should return the error NFS4ERR_WRONG_TYPE if the
	object is not of type NF4LNK.		object is not of type NF4LNK.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_REMOVE" numbered="true" toc="default">
	$ -->		<name>Operation 28: REMOVE - Remove File System Object</name>
	<!-- Copyright (C) The IETF Trust (2007) -->		<section toc="exclude" anchor="OP_REMOVE_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_REMOVE" title="Operation 28: REMOVE - Remove File System Obj		<sourcecode type="xdr"><![CDATA[
	ect" >
	<section toc="exclude" anchor="OP_REMOVE_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct REMOVE4args {		struct REMOVE4args {
	/* CURRENT_FH: directory */		/* CURRENT_FH: directory */
	component4 target;		component4 target;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_REMOVE_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_REMOVE_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct REMOVE4resok {		struct REMOVE4resok {
	change_info4 cinfo;		change_info4 cinfo;
	};		};
	union REMOVE4res switch (nfsstat4 status) {		union REMOVE4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	REMOVE4resok resok4;		REMOVE4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_REMOVE_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_REMOVE_DESCRIPTION" title="DESCRIPTION">
	<t>
	The REMOVE operation removes (deletes) a directory entry named by		The REMOVE operation removes (deletes) a directory entry named by
	filename from the directory corresponding to the current filehandle.		filename from the directory corresponding to the current filehandle.
	If the entry in the directory was the last reference to the		If the entry in the directory was the last reference to the
	corresponding file system object, the object may be destroyed.		corresponding file system object, the object may be destroyed.
	The directory may be either of type NF4DIR or NF4ATTRDIR.		The directory may be either of type NF4DIR or NF4ATTRDIR.
	</t>		</t>
	<t>		<t>
	For the directory where the filename was removed, the server		For the directory where the filename was removed, the server
	returns change_info4 information in cinfo. With the atomic field of		returns change_info4 information in cinfo. With the atomic field of
	the change_info4 data type, the server will indicate if the before and		the change_info4 data type, the server will indicate if the before and
	after change attributes were obtained atomically with respect to the		after change attributes were obtained atomically with respect to the
	removal.		removal.
	</t>		</t>
	<t>		<t>
	If the target has a length of zero, or if		If the target has a length of zero, or if
	the target does not obey the UTF-8 definition (and		the target does not obey the UTF-8 definition (and
	the server is enforcing UTF-8 encoding; see <xref		the server is enforcing UTF-8 encoding; see <xref target="utf8_caps" forma
	target="utf8_caps"/>), the error NFS4ERR_INVAL will		t="default"/>), the error NFS4ERR_INVAL will
	be returned.		be returned.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_REMOVE_IMPLEMENTATION" title="IMPLEMENTATION		<section toc="exclude" anchor="OP_REMOVE_IMPLEMENTATION" numbered="true"
	">		>
	<t>		<name>IMPLEMENTATION</name>
			<t>
	NFSv3 required a different operator RMDIR for directory		NFSv3 required a different operator RMDIR for directory
	removal and REMOVE for non-directory removal. This allowed clients to		removal and REMOVE for non-directory removal. This allowed clients to
	skip checking the file type when being passed a non-directory delete		skip checking the file type when being passed a non-directory delete
	system call (e.g., <xref target="unlink">unlink()</xref> in POSIX) to remo ve a directory, as well as		system call (e.g., <xref target="unlink" format="default">unlink()</xref> in POSIX) to remove a directory, as well as
	the converse (e.g., a rmdir() on a non-directory) because they knew the		the converse (e.g., a rmdir() on a non-directory) because they knew the
	server would check the file type. NFSv4.1 REMOVE can be used to		server would check the file type. NFSv4.1 REMOVE can be used to
	delete any directory entry independent of its file type. The		delete any directory entry independent of its file type. The
	implementor of an NFSv4.1 client's entry points from the		implementor of an NFSv4.1 client's entry points from the
	unlink() and rmdir() system calls should first check the file type		unlink() and rmdir() system calls should first check the file type
	against the types the system call is allowed to remove before sending		against the types the system call is allowed to remove before sending
	a REMOVE operation. Alternatively, the implementor can produce a COMPOUND call		a REMOVE operation. Alternatively, the implementor can produce a COMPOUND call
	that includes a LOOKUP/VERIFY sequence of operations to verify the file ty pe before		that includes a LOOKUP/VERIFY sequence of operations to verify the file ty pe before
	a REMOVE operation in the same COMPOUND call.		a REMOVE operation in the same COMPOUND call.
	</t>		</t>
	<t>		<t>
	The concept of last reference is server		The concept of last reference is server
	specific. However, if the numlinks field in the		specific. However, if the numlinks field in the
	previous attributes of the object had the value 1,		previous attributes of the object had the value 1,
	the client should not rely on referring to the		the client should not rely on referring to the
	object via a filehandle. Likewise, the client		object via a filehandle. Likewise, the client
	should not rely on the resources (disk space,		should not rely on the resources (disk space,
	directory entry, and so on) formerly associated		directory entry, and so on) formerly associated
	with the object becoming immediately available.		with the object becoming immediately available.
	Thus, if a client needs to be able to continue to		Thus, if a client needs to be able to continue to
	access a file after using REMOVE to remove it, the		access a file after using REMOVE to remove it, the
	client should take steps to make sure that the file		client should take steps to make sure that the file
	will still be accessible. While the traditional		will still be accessible. While the traditional
	mechanism used is to RENAME the file from its old		mechanism used is to RENAME the file from its old
	name to a new hidden name, the NFSv4.1 OPEN operation		name to a new hidden name, the NFSv4.1 OPEN operation
	MAY return a result flag, OPEN4_RESULT_PRESERVE_UNLINKED,		<bcp14>MAY</bcp14> return a result flag, OPEN4_RESULT_PRESERVE_UNLINKED,
	which indicates to the client that the file will be		which indicates to the client that the file will be
	preserved if the file has an outstanding open (see <xref		preserved if the file has an outstanding open (see <xref target="OP_OPEN"
	target="OP_OPEN"/>).		format="default"/>).
	</t>		</t>
	<t>		<t>
	If the server finds that the file is still open when the REMOVE		If the server finds that the file is still open when the REMOVE
	arrives:		arrives:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
	The server SHOULD NOT delete the file's directory entry if the		<li>
			The server <bcp14>SHOULD NOT</bcp14> delete the file's directory entry
			if the
	file was opened with OPEN4_SHARE_DENY_WRITE or		file was opened with OPEN4_SHARE_DENY_WRITE or
	OPEN4_SHARE_DENY_BOTH.		OPEN4_SHARE_DENY_BOTH.
	</t>		</li>
	<t>		<li>
	If the file was not opened with OPEN4_SHARE_DENY_WRITE or		If the file was not opened with OPEN4_SHARE_DENY_WRITE or
	OPEN4_SHARE_DENY_BOTH, the server SHOULD delete the file's		OPEN4_SHARE_DENY_BOTH, the server <bcp14>SHOULD</bcp14> delete the fil e's
	directory entry. However, until last CLOSE of the file,		directory entry. However, until last CLOSE of the file,
	the server MAY continue to allow access to the file via		the server <bcp14>MAY</bcp14> continue to allow access to the file via
	its filehandle.		its filehandle.
	</t>		</li>
	<t>		<li>
	The server MUST NOT delete the directory		The server <bcp14>MUST NOT</bcp14> delete the directory
	entry if the reply from OPEN had the flag		entry if the reply from OPEN had the flag
	OPEN4_RESULT_PRESERVE_UNLINKED set.		OPEN4_RESULT_PRESERVE_UNLINKED set.
	</t>		</li>
			</ul>
	</list>		<t>
	</t>		The server <bcp14>MAY</bcp14> implement its own restrictions on removal
	<t>
	The server MAY implement its own restrictions on removal
	of a file while it is open. The server might disallow		of a file while it is open. The server might disallow
	such a REMOVE (or a removal that occurs		such a REMOVE (or a removal that occurs
	as part of RENAME). The conditions that influence the restrictions		as part of RENAME). The conditions that influence the restrictions
	on removal of a file while it is still open include:		on removal of a file while it is still open include:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	Whether certain access protocols (i.e., not just		Whether certain access protocols (i.e., not just
	NFS) are holding the file open.		NFS) are holding the file open.
	</t>		</li>
			<li>
	<t>
	Whether particular options, access modes, or policies on the		Whether particular options, access modes, or policies on the
	server are enabled.		server are enabled.
	</t>		</li>
			</ul>
	</list>		<t>
	</t>
	<t>
	If a file has an outstanding OPEN and this prevents the		If a file has an outstanding OPEN and this prevents the
	removal of the file's directory entry,		removal of the file's directory entry,
	the error NFS4ERR_FILE_OPEN is returned.		the error NFS4ERR_FILE_OPEN is returned.
	</t>		</t>
			<t>
	<t>
	Where the determination above cannot be made		Where the determination above cannot be made
	definitively because delegations are being held,		definitively because delegations are being held,
	they MUST be recalled to allow processing of the		they <bcp14>MUST</bcp14> be recalled to allow processing of the
	REMOVE to continue. When a delegation is held,		REMOVE to continue. When a delegation is held,
	the server has no reliable knowledge of the status of OPENs for		the server has no reliable knowledge of the status of OPENs for
	that client, so unless		that client, so unless
	there are files opened with the particular deny modes		there are files opened with the particular deny modes
	by clients without delegations, the determination		by clients without delegations, the determination
	cannot be made until delegations are recalled, and		cannot be made until delegations are recalled, and
	the operation cannot proceed until each sufficient		the operation cannot proceed until each sufficient
	delegation has been returned or revoked to allow		delegation has been returned or revoked to allow
	the server to make a correct determination.		the server to make a correct determination.
	</t>		</t>
	<t>		<t>
	In all cases in which delegations are recalled, the server		In all cases in which delegations are recalled, the server
	is likely to return one or more NFS4ERR_DELAY errors while		is likely to return one or more NFS4ERR_DELAY errors while
	delegations remain outstanding.		delegations remain outstanding.
	</t>		</t>
			<t>
	<t>
	If the current filehandle designates a directory for		If the current filehandle designates a directory for
	which another client holds a directory delegation,		which another client holds a directory delegation,
	then, unless the situation can be resolved by sending		then, unless the situation can be resolved by sending
	a notification, the directory delegation MUST be		a notification, the directory delegation <bcp14>MUST</bcp14> be
	recalled, and the operation MUST NOT proceed until		recalled, and the operation <bcp14>MUST NOT</bcp14> proceed until
	the delegation is returned or revoked. Except where		the delegation is returned or revoked. Except where
	this happens very quickly, one or more NFS4ERR_DELAY		this happens very quickly, one or more NFS4ERR_DELAY
	errors will be returned to requests made while		errors will be returned to requests made while
	delegation remains outstanding.		delegation remains outstanding.
	</t>		</t>
	<t>		<t>
	When the current filehandle designates a directory		When the current filehandle designates a directory
	for which one or more directory delegations		for which one or more directory delegations
	exist, then, when those delegations request		exist, then, when those delegations request
	such notifications, NOTIFY4_REMOVE_ENTRY will be		such notifications, NOTIFY4_REMOVE_ENTRY will be
	generated as a result of this operation.		generated as a result of this operation.
	</t>		</t>
			<t>
	<t>
	Note that when a remove occurs as a result of a		Note that when a remove occurs as a result of a
	RENAME, NOTIFY4_REMOVE_ENTRY will only be generated		RENAME, NOTIFY4_REMOVE_ENTRY will only be generated
	if the removal happens as a separate operation.		if the removal happens as a separate operation.
	In the case in which the removal is integrated and		In the case in which the removal is integrated and
	atomic with RENAME, the notification of the removal		atomic with RENAME, the notification of the removal
	is integrated with notification for the RENAME. See		is integrated with notification for the RENAME. See
	the discussion of the NOTIFY4_RENAME_ENTRY		the discussion of the NOTIFY4_RENAME_ENTRY
	notification in <xref target="OP_CB_NOTIFY"/>.		notification in <xref target="OP_CB_NOTIFY" format="default"/>.
	</t>
	</section>
	</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->
	<!-- Copyright (C) The IETF Trust (2007) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="OP_RENAME" title="Operation 29: RENAME - Rename Directory Entry
	" >
	<section toc="exclude" anchor="OP_RENAME_ARGUMENTS" title="ARGUMENTS">		</t>
	<figure>		</section>
	<artwork>		</section>
			<section anchor="OP_RENAME" numbered="true" toc="default">
			<name>Operation 29: RENAME - Rename Directory Entry</name>
			<section toc="exclude" anchor="OP_RENAME_ARGUMENTS" numbered="true">
			<name>ARGUMENTS</name>
			<sourcecode type="xdr"><![CDATA[
	struct RENAME4args {		struct RENAME4args {
	/* SAVED_FH: source directory */		/* SAVED_FH: source directory */
	component4 oldname;		component4 oldname;
	/* CURRENT_FH: target directory */		/* CURRENT_FH: target directory */
	component4 newname;		component4 newname;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_RENAME_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_RENAME_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct RENAME4resok {		struct RENAME4resok {
	change_info4 source_cinfo;		change_info4 source_cinfo;
	change_info4 target_cinfo;		change_info4 target_cinfo;
	};		};
	union RENAME4res switch (nfsstat4 status) {		union RENAME4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	RENAME4resok resok4;		RENAME4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_RENAME_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_RENAME_DESCRIPTION" title="DESCRIPTION">
	<t>
	The RENAME operation renames the object identified by oldname in the		The RENAME operation renames the object identified by oldname in the
	source directory corresponding to the saved filehandle, as set by the		source directory corresponding to the saved filehandle, as set by the
	SAVEFH operation, to newname in the target directory corresponding to		SAVEFH operation, to newname in the target directory corresponding to
	the current filehandle. The operation is required to be atomic to the		the current filehandle. The operation is required to be atomic to the
	client. Source and target directories MUST reside on the same		client. Source and target directories <bcp14>MUST</bcp14> reside on the s ame
	file system on the server. On success, the current filehandle will		file system on the server. On success, the current filehandle will
	continue to be the target directory.		continue to be the target directory.
	</t>		</t>
	<t>		<t>
	If the target directory already contains an entry with the name		If the target directory already contains an entry with the name
	newname, the source object MUST be compatible with the target: either		newname, the source object <bcp14>MUST</bcp14> be compatible with the targ
	both are non-directories or both are directories and the target MUST		et: either
			both are non-directories or both are directories and the target <bcp14>MUS
			T</bcp14>
	be empty.		be empty.
	If compatible, the existing target is removed before the		If compatible, the existing target is removed before the
	rename occurs or, preferably, the target is removed atomically as		rename occurs or, preferably, the target is removed atomically as
	part of the rename.		part of the rename.
	See <xref target="OP_REMOVE_IMPLEMENTATION" />		See <xref target="OP_REMOVE_IMPLEMENTATION" format="default"/>
	for client and server actions whenever a target is removed.		for client and server actions whenever a target is removed.
	Note however that when the removal is performed atomically with the		Note however that when the removal is performed atomically with the
	rename, certain parts of the removal described there are integrated		rename, certain parts of the removal described there are integrated
	with the rename. For example, notification of the removal will not		with the rename. For example, notification of the removal will not
	be via a NOTIFY4_REMOVE_ENTRY but will be indicated as part of the		be via a NOTIFY4_REMOVE_ENTRY but will be indicated as part of the
	NOTIFY4_ADD_ENTRY or NOTIFY4_RENAME_ENTRY generated by the rename.		NOTIFY4_ADD_ENTRY or NOTIFY4_RENAME_ENTRY generated by the rename.
	</t>		</t>
	<t>		<t>
	If the source object and the target are not		If the source object and the target are not
	compatible or if the target is a directory but not empty, the server		compatible or if the target is a directory but not empty, the server
	will return the error NFS4ERR_EXIST.		will return the error NFS4ERR_EXIST.
	</t>		</t>
	<t>		<t>
	If oldname and newname both refer to the same		If oldname and newname both refer to the same
	file (e.g., they might be hard links of each		file (e.g., they might be hard links of each
	other), then unless the file is open (see <xref		other), then unless the file is open (see <xref target="OP_RENAME_IMPLEMEN
	target="OP_RENAME_IMPLEMENTATION"/>), RENAME MUST		TATION" format="default"/>), RENAME <bcp14>MUST</bcp14>
	perform no action and return NFS4_OK.		perform no action and return NFS4_OK.
	</t>		</t>
	<t>		<t>
	For both directories involved in the RENAME, the server returns		For both directories involved in the RENAME, the server returns
	change_info4 information. With the atomic field of the change_info4		change_info4 information. With the atomic field of the change_info4
	data type, the server will indicate if the before and after change		data type, the server will indicate if the before and after change
	attributes were obtained atomically with respect to the rename.		attributes were obtained atomically with respect to the rename.
	</t>		</t>
	<t>		<t>
	If oldname refers to a named attribute and the saved and current		If oldname refers to a named attribute and the saved and current
	filehandles refer to different file system objects, the server will		filehandles refer to different file system objects, the server will
	return NFS4ERR_XDEV just as if the saved and current filehandles		return NFS4ERR_XDEV just as if the saved and current filehandles
	represented directories on different file systems.		represented directories on different file systems.
	</t>		</t>
	<t>		<t>
	If oldname or newname has a length of zero, or if oldname or		If oldname or newname has a length of zero, or if oldname or
	newname does not obey the UTF-8 definition, the error NFS4ERR_INVAL		newname does not obey the UTF-8 definition, the error NFS4ERR_INVAL
	will be returned.		will be returned.
	</t>		</t>
	</section>		</section>
			<section toc="exclude" anchor="OP_RENAME_IMPLEMENTATION" numbered="true"
	<section toc="exclude" anchor="OP_RENAME_IMPLEMENTATION" title="IMPLEMENTATION		>
	">		<name>IMPLEMENTATION</name>
	<t>		<t>
	The server MAY impose restrictions on the RENAME		The server <bcp14>MAY</bcp14> impose restrictions on the RENAME
	operation such that RENAME may not be done when the		operation such that RENAME may not be done when the
	file being renamed is open or when that open is done		file being renamed is open or when that open is done
	by particular protocols, or with particular options		by particular protocols, or with particular options
	or access modes. Similar restrictions may be applied		or access modes. Similar restrictions may be applied
	when a file exists with the target name and is open.		when a file exists with the target name and is open.
	When RENAME is rejected because of such restrictions,		When RENAME is rejected because of such restrictions,
	the error NFS4ERR_FILE_OPEN is returned.		the error NFS4ERR_FILE_OPEN is returned.
	</t>		</t>
	<t>		<t>
	When oldname and rename refer to the same file and		When oldname and rename refer to the same file and
	that file is open in a fashion such that RENAME		that file is open in a fashion such that RENAME
	would normally be rejected with NFS4ERR_FILE_OPEN		would normally be rejected with NFS4ERR_FILE_OPEN
	if oldname and newname were different files, then		if oldname and newname were different files, then
	RENAME SHOULD be rejected with NFS4ERR_FILE_OPEN.		RENAME <bcp14>SHOULD</bcp14> be rejected with NFS4ERR_FILE_OPEN.
	</t>		</t>
	<t>		<t>
	If a server does implement such restrictions and those restrictions		If a server does implement such restrictions and those restrictions
	include cases of NFSv4 opens preventing successful execution of		include cases of NFSv4 opens preventing successful execution of
	a rename, the server needs to recall any delegations that could		a rename, the server needs to recall any delegations that could
	hide the existence of opens relevant to that decision. This is		hide the existence of opens relevant to that decision. This is
	because when a client holds a delegation, the server		because when a client holds a delegation, the server
	might not have an accurate account of the opens for that client, since		might not have an accurate account of the opens for that client, since
	the client may execute OPENs and CLOSEs locally. The RENAME operation		the client may execute OPENs and CLOSEs locally. The RENAME operation
	need only be delayed until a definitive result can be obtained. For		need only be delayed until a definitive result can be obtained. For
	example, if there are multiple delegations and one of them establishes		example, if there are multiple delegations and one of them establishes
	an open whose presence would prevent the rename, given the server's		an open whose presence would prevent the rename, given the server's
	semantics, NFS4ERR_FILE_OPEN may be returned to the caller as soon		semantics, NFS4ERR_FILE_OPEN may be returned to the caller as soon
	as that delegation is returned without waiting for other delegations		as that delegation is returned without waiting for other delegations
	to be returned. Similarly, if such opens are not associated with		to be returned. Similarly, if such opens are not associated with
	delegations, NFS4ERR_FILE_OPEN can be returned immediately with no		delegations, NFS4ERR_FILE_OPEN can be returned immediately with no
	delegation recall being done.		delegation recall being done.
	</t>		</t>
	<t>		<t>
	If the current filehandle or the saved filehandle designates a		If the current filehandle or the saved filehandle designates a
	directory for which another client holds a directory delegation,		directory for which another client holds a directory delegation,
	then, unless the situation can be resolved by sending a notification,		then, unless the situation can be resolved by sending a notification,
	the delegation MUST be recalled, and the operation cannot proceed		the delegation <bcp14>MUST</bcp14> be recalled, and the operation cannot p roceed
	until the delegation is returned or revoked. Except where this		until the delegation is returned or revoked. Except where this
	happens very quickly, one or more NFS4ERR_DELAY errors will be		happens very quickly, one or more NFS4ERR_DELAY errors will be
	returned to requests made while delegation remains outstanding.		returned to requests made while delegation remains outstanding.
	</t>		</t>
	<t>		<t>
	When the current and saved filehandles are the		When the current and saved filehandles are the
	same and they designate a directory for which one		same and they designate a directory for which one
	or more directory delegations exist, then, when		or more directory delegations exist, then, when
	those delegations request such notifications,		those delegations request such notifications,
	a notification of type NOTIFY4_RENAME_ENTRY		a notification of type NOTIFY4_RENAME_ENTRY
	will be generated as a result of this operation.		will be generated as a result of this operation.
	When oldname and rename refer to the same file,		When oldname and rename refer to the same file,
	no notification is generated (because, as <xref		no notification is generated (because, as <xref target="OP_RENAME_DESCRIPT
	target="OP_RENAME_DESCRIPTION"/> states, the server		ION" format="default"/> states, the server
	MUST take no action). When a file is removed		<bcp14>MUST</bcp14> take no action). When a file is removed
	because it has the same name as the target, if		because it has the same name as the target, if
	that removal is done atomically with the rename,		that removal is done atomically with the rename,
	a NOTIFY4_REMOVE_ENTRY notification will not be		a NOTIFY4_REMOVE_ENTRY notification will not be
	generated. Instead, the deletion of the file will		generated. Instead, the deletion of the file will
	be reported as part of the NOTIFY4_RENAME_ENTRY		be reported as part of the NOTIFY4_RENAME_ENTRY
	notification.		notification.
	</t>		</t>
	<t>		<t>
	When the current and saved filehandles are not the same:		When the current and saved filehandles are not the same:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	If the current filehandle designates a directory for which		If the current filehandle designates a directory for which
	one or more directory delegations exist, then, when those		one or more directory delegations exist, then, when those
	delegations request such notifications, NOTIFY4_ADD_ENTRY		delegations request such notifications, NOTIFY4_ADD_ENTRY
	will be generated as a result of this operation. When a file		will be generated as a result of this operation. When a file
	is removed because it has the same name as the target, if that		is removed because it has the same name as the target, if that
	removal is done atomically with the rename, a		removal is done atomically with the rename, a
	NOTIFY4_REMOVE_ENTRY notification will not be generated.		NOTIFY4_REMOVE_ENTRY notification will not be generated.
	Instead, the deletion of the file will be reported as part		Instead, the deletion of the file will be reported as part
	of the NOTIFY4_ADD_ENTRY notification.		of the NOTIFY4_ADD_ENTRY notification.
	</t>		</li>
	<t>		<li>
	If the saved filehandle designates a directory for which		If the saved filehandle designates a directory for which
	one or more directory delegations exist, then, when those		one or more directory delegations exist, then, when those
	delegations request such notifications, NOTIFY4_REMOVE_ENTRY		delegations request such notifications, NOTIFY4_REMOVE_ENTRY
	will be generated as a result of this operation.		will be generated as a result of this operation.
	</t>		</li>
	</list>		</ul>
			<t>
	</t>
	<t>
	If the object being renamed has file delegations		If the object being renamed has file delegations
	held by clients other than the one doing the RENAME,		held by clients other than the one doing the RENAME,
	the delegations MUST be recalled, and the		the delegations <bcp14>MUST</bcp14> be recalled, and the
	operation cannot proceed		operation cannot proceed
	until each such delegation is returned		until each such delegation is returned
	or revoked. Note that in the case of multiply linked files,		or revoked. Note that in the case of multiply linked files,
	the delegation recall requirement applies even if the		the delegation recall requirement applies even if the
	delegation was obtained through a different name than the		delegation was obtained through a different name than the
	one being renamed.		one being renamed.
	In all cases in which delegations are recalled, the server		In all cases in which delegations are recalled, the server
	is likely to return one or more NFS4ERR_DELAY errors while the		is likely to return one or more NFS4ERR_DELAY errors while the
	delegation(s) remains outstanding, although it might not do that if the		delegation(s) remains outstanding, although it might not do that if the
	delegations are returned quickly.		delegations are returned quickly.
	</t>		</t>
	<t>		<t>
	The RENAME operation must be atomic to the client. The statement		The RENAME operation must be atomic to the client. The statement
	"source and target directories MUST reside on the same file system		"source and target directories <bcp14>MUST</bcp14> reside on the same file system
	on the server"		on the server"
	means that the fsid fields in the attributes for the		means that the fsid fields in the attributes for the
	directories are the same. If they reside on different file systems,		directories are the same. If they reside on different file systems,
	the error NFS4ERR_XDEV is returned.		the error NFS4ERR_XDEV is returned.
	</t>		</t>
	<t>		<t>
	Based on the value of the fh_expire_type attribute for the object, the		Based on the value of the fh_expire_type attribute for the object, the
	filehandle may or may not expire on a RENAME. However, server		filehandle may or may not expire on a RENAME. However, server
	implementors are strongly encouraged to attempt to keep filehandles		implementors are strongly encouraged to attempt to keep filehandles
	from expiring in this fashion.		from expiring in this fashion.
	</t>		</t>
	<t>		<t>
	On some servers, the file names "." and ".." are illegal as either		On some servers, the file names "." and ".." are illegal as either
	oldname or newname, and will result in the error NFS4ERR_BADNAME.		oldname or newname, and will result in the error NFS4ERR_BADNAME.
	In addition, on many servers the case of oldname or newname being		In addition, on many servers the case of oldname or newname being
	an alias for the source directory will be checked for. Such servers		an alias for the source directory will be checked for. Such servers
	will return the error NFS4ERR_INVAL in these cases.		will return the error NFS4ERR_INVAL in these cases.
	</t>		</t>
	<t>		<t>
	If either of the source or target filehandles are not directories, the		If either of the source or target filehandles are not directories, the
	server will return NFS4ERR_NOTDIR.		server will return NFS4ERR_NOTDIR.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_RESTOREFH" numbered="true" toc="default">
	$ -->		<name>Operation 31: RESTOREFH - Restore Saved Filehandle</name>
	<!-- Copyright (C) The IETF Trust (2007) -->		<section toc="exclude" anchor="OP_RESTOREFH_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_RESTOREFH" title="Operation 31: RESTOREFH - Restore Saved Fi		<sourcecode type="xdr"><![CDATA[
	lehandle" >
	<section toc="exclude" anchor="OP_RESTOREFH_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	/* SAVED_FH: */		/* SAVED_FH: */
	void;		void;]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_RESTOREFH_RESULTS" numbered="true">
	</section>		<name>RESULTS</name>
			<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_RESTOREFH_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct RESTOREFH4res {		struct RESTOREFH4res {
	/*		/*
	* If status is NFS4_OK,		* If status is NFS4_OK,
	* new CURRENT_FH: value of saved fh		* new CURRENT_FH: value of saved fh
	*/		*/
	nfsstat4 status;		nfsstat4 status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_RESTOREFH_DESCRIPTION" numbered="true"
	</figure>		>
	</section>		<name>DESCRIPTION</name>
			<t>
	<section toc="exclude" anchor="OP_RESTOREFH_DESCRIPTION" title="DESCRIPTION">
	<t>
	The RESTOREFH operation sets the current filehandle and stateid to the val ues in the		The RESTOREFH operation sets the current filehandle and stateid to the val ues in the
	saved filehandle and stateid. If		saved filehandle and stateid. If
	there is no saved filehandle, then the server will		there is no saved filehandle, then the server will
	return the error NFS4ERR_NOFILEHANDLE.		return the error NFS4ERR_NOFILEHANDLE.
	</t>		</t>
	<t>		<t>
	See <xref target="current_filehandle"/> for more details on the		See <xref target="current_filehandle" format="default"/> for more details
			on the
	current filehandle.		current filehandle.
	</t>		</t>
	<t>		<t>
	See <xref target="current_stateid"/> for more details on the current		See <xref target="current_stateid" format="default"/> for more details on
			the current
	stateid.		stateid.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_RESTOREFH_IMPLEMENTATION" title="IMPLEMENTAT		<section toc="exclude" anchor="OP_RESTOREFH_IMPLEMENTATION" numbered="tr
	ION">		ue">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	Operations like OPEN and LOOKUP use the current filehandle		Operations like OPEN and LOOKUP use the current filehandle
	to represent a directory and replace it with a new filehandle.		to represent a directory and replace it with a new filehandle.
	Assuming that the previous filehandle was saved with a SAVEFH operator,		Assuming that the previous filehandle was saved with a SAVEFH operator,
	the previous filehandle can be restored as the current filehandle.		the previous filehandle can be restored as the current filehandle.
	This is commonly used to obtain post-operation attributes for		This is commonly used to obtain post-operation attributes for
	the directory, e.g.,		the directory, e.g.,
	<figure>		</t>
	<artwork>		<sourcecode type="xdr"><![CDATA[
	PUTFH (directory filehandle)		PUTFH (directory filehandle)
	SAVEFH		SAVEFH
	GETATTR attrbits (pre-op dir attrs)		GETATTR attrbits (pre-op dir attrs)
	CREATE optbits "foo" attrs		CREATE optbits "foo" attrs
	GETATTR attrbits (file attributes)		GETATTR attrbits (file attributes)
	RESTOREFH		RESTOREFH
	GETATTR attrbits (post-op dir attrs)		GETATTR attrbits (post-op dir attrs)]]></sourcecode>
	</artwork>		</section>
	</figure>		</section>
	</t>		<section anchor="OP_SAVEFH" numbered="true" toc="default">
	</section>		<name>Operation 32: SAVEFH - Save Current Filehandle</name>
	</section>		<section toc="exclude" anchor="OP_SAVEFH_ARGUMENTS" numbered="true">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>ARGUMENTS</name>
	$ -->		<sourcecode type="xdr"><![CDATA[
	<!-- Copyright (C) The IETF Trust (2007) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="OP_SAVEFH" title="Operation 32: SAVEFH - Save Current Filehandl
	e" >
	<section toc="exclude" anchor="OP_SAVEFH_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	/* CURRENT_FH: */		/* CURRENT_FH: */
	void;		void;]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_SAVEFH_RESULTS" numbered="true">
	</section>		<name>RESULTS</name>
			<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_SAVEFH_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct SAVEFH4res {		struct SAVEFH4res {
	/*		/*
	* If status is NFS4_OK,		* If status is NFS4_OK,
	* new SAVED_FH: value of current fh		* new SAVED_FH: value of current fh
	*/		*/
	nfsstat4 status;		nfsstat4 status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_SAVEFH_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_SAVEFH_DESCRIPTION" title="DESCRIPTION">
	<t>
	The SAVEFH operation saves the current filehandle and stateid.		The SAVEFH operation saves the current filehandle and stateid.
	If a previous filehandle was saved, then		If a previous filehandle was saved, then
	it is no longer accessible. The saved filehandle can be restored as		it is no longer accessible. The saved filehandle can be restored as
	the current filehandle with the RESTOREFH operator.		the current filehandle with the RESTOREFH operator.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	<t>		<t>
	See <xref target="current_filehandle"/> for more details on the		See <xref target="current_filehandle" format="default"/> for more details
			on the
	current filehandle.		current filehandle.
	</t>		</t>
	<t>		<t>
	See <xref target="current_stateid"/> for more details on the current		See <xref target="current_stateid" format="default"/> for more details on
			the current
	stateid.		stateid.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_SAVEFH_IMPLEMENTATION" title="IMPLEMENTATION		<section toc="exclude" anchor="OP_SAVEFH_IMPLEMENTATION" numbered="true"
	">		>
	<t>		<name>IMPLEMENTATION</name>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="OP_SECINFO" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 33: SECINFO - Obtain Available Security</name>
	$ -->		<section toc="exclude" anchor="OP_SECINFO_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<name>ARGUMENTS</name>
	<!-- Copyright (C) The Internet Society (2006) -->		<sourcecode type="xdr"><![CDATA[
	<section anchor="OP_SECINFO" title="Operation 33: SECINFO - Obtain Available Sec
	urity" >
	<section toc="exclude" anchor="OP_SECINFO_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct SECINFO4args {		struct SECINFO4args {
	/* CURRENT_FH: directory */		/* CURRENT_FH: directory */
	component4 name;		component4 name;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_SECINFO_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_SECINFO_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	/*		/*
	* From RFC 2203		* From RFC 2203
	*/		*/
	enum rpc_gss_svc_t {		enum rpc_gss_svc_t {
	RPC_GSS_SVC_NONE = 1,		RPC_GSS_SVC_NONE = 1,
	RPC_GSS_SVC_INTEGRITY = 2,		RPC_GSS_SVC_INTEGRITY = 2,
	RPC_GSS_SVC_PRIVACY = 3		RPC_GSS_SVC_PRIVACY = 3
	};		};
	struct rpcsec_gss_info {		struct rpcsec_gss_info {
	skipping to change at line 34104 ¶		skipping to change at line 34262 ¶
	};		};
	/* RPCSEC_GSS has a value of '6' - See RFC 2203 */		/* RPCSEC_GSS has a value of '6' - See RFC 2203 */
	union secinfo4 switch (uint32_t flavor) {		union secinfo4 switch (uint32_t flavor) {
	case RPCSEC_GSS:		case RPCSEC_GSS:
	rpcsec_gss_info flavor_info;		rpcsec_gss_info flavor_info;
	default:		default:
	void;		void;
	};		};
	typedef secinfo4 SECINFO4resok&lt;>;		typedef secinfo4 SECINFO4resok<>;
	union SECINFO4res switch (nfsstat4 status) {		union SECINFO4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	/* CURRENTFH: consumed */		/* CURRENTFH: consumed */
	SECINFO4resok resok4;		SECINFO4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_SECINFO_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_SECINFO_DESCRIPTION" title="DESCRIPTION">
	<t>
	The SECINFO operation is used by the client to obtain a list of		The SECINFO operation is used by the client to obtain a list of
	valid RPC authentication flavors for a specific directory		valid RPC authentication flavors for a specific directory
	filehandle, file name pair. SECINFO should apply the same		filehandle, file name pair. SECINFO should apply the same
	access methodology used for LOOKUP when evaluating the name.		access methodology used for LOOKUP when evaluating the name.
	Therefore, if the requester does not have the appropriate access		Therefore, if the requester does not have the appropriate access
	to LOOKUP the name, then SECINFO MUST behave the same way and		to LOOKUP the name, then SECINFO <bcp14>MUST</bcp14> behave the same way a nd
	return NFS4ERR_ACCESS.		return NFS4ERR_ACCESS.
	</t>		</t>
	<t>		<t>
	The result will contain an array that represents the security		The result will contain an array that represents the security
	mechanisms available, with an order corresponding to the		mechanisms available, with an order corresponding to the
	server's preferences, the most preferred being first in the		server's preferences, the most preferred being first in the
	array. The client is free to pick whatever security mechanism it		array. The client is free to pick whatever security mechanism it
	both desires and supports, or to pick in the server's preference		both desires and supports, or to pick in the server's preference
	order the first one it supports. The array entries are		order the first one it supports. The array entries are
	represented by the secinfo4 structure. The field 'flavor' will		represented by the secinfo4 structure. The field 'flavor' will
	contain a value of AUTH_NONE, AUTH_SYS (as defined in <xref		contain a value of AUTH_NONE, AUTH_SYS (as defined in <xref target="RFC553
	target="RFC5531">RFC 5531</xref>), or RPCSEC_GSS (as defined in		1" format="default">RFC 5531</xref>), or RPCSEC_GSS (as defined in
	<xref target="RFC2203">RFC 2203</xref>). The field flavor can		<xref target="RFC2203" format="default">RFC 2203</xref>). The field flavor
			can
	also be any other security flavor registered with IANA.		also be any other security flavor registered with IANA.
	</t>		</t>
	<t>		<t>
	For the flavors AUTH_NONE and AUTH_SYS, no additional security		For the flavors AUTH_NONE and AUTH_SYS, no additional security
	information is returned. The same is true of many (if not most)		information is returned. The same is true of many (if not most)
	other security flavors, including AUTH_DH. For a return value of		other security flavors, including AUTH_DH. For a return value of
	RPCSEC_GSS, a security triple is returned that contains the		RPCSEC_GSS, a security triple is returned that contains the
	mechanism object identifier (OID, as defined in <xref		mechanism object identifier (OID, as defined in <xref target="RFC2743" for
	target="RFC2743">RFC 2743</xref>), the quality of protection (as		mat="default">RFC 2743</xref>), the quality of protection (as
	defined in <xref target="RFC2743">RFC 2743</xref>), and the		defined in <xref target="RFC2743" format="default">RFC 2743</xref>), and t
	service type (as defined in <xref		he
	target="RFC2203">RFC 2203</xref>). It is possible for SECINFO to		service type (as defined in <xref target="RFC2203" format="default">RFC 22
			03</xref>). It is possible for SECINFO to
	return multiple entries with flavor equal to RPCSEC_GSS with		return multiple entries with flavor equal to RPCSEC_GSS with
	different security triple values.		different security triple values.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle is consumed (see		On success, the current filehandle is consumed (see
	<xref target="aftersecinfo" />), and if the		<xref target="aftersecinfo" format="default"/>), and if the
	next operation after SECINFO tries to use the current filehandle,		next operation after SECINFO tries to use the current filehandle,
	that operation will fail with the status NFS4ERR_NOFILEHANDLE.		that operation will fail with the status NFS4ERR_NOFILEHANDLE.
	</t>		</t>
	<t>		<t>
	If the name has a length of zero, or if the name does not obey		If the name has a length of zero, or if the name does not obey
	the UTF-8 definition (assuming UTF-8 capabilities are enabled; see		the UTF-8 definition (assuming UTF-8 capabilities are enabled; see
	<xref target="utf8_caps"/>), the error NFS4ERR_INVAL will be returned.		<xref target="utf8_caps" format="default"/>), the error NFS4ERR_INVAL will
	</t>		be returned.
	<t>		</t>
	See <xref target="Security_Service_Negotiation"/>		<t>
			See <xref target="Security_Service_Negotiation" format="default"/>
	for additional information on the use of SECINFO.		for additional information on the use of SECINFO.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_SECINFO_IMPLEMENTATION" title="IMPLEMENTATIO		<section toc="exclude" anchor="OP_SECINFO_IMPLEMENTATION" numbered="true
	N">		">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	The SECINFO operation is expected to be used by the NFS client		The SECINFO operation is expected to be used by the NFS client
	when the error value of NFS4ERR_WRONGSEC is returned from		when the error value of NFS4ERR_WRONGSEC is returned from
	another NFS operation. This signifies to the client that the		another NFS operation. This signifies to the client that the
	server&apos;s security policy is different from what the client is		server's security policy is different from what the client is
	currently using. At this point, the client is expected to		currently using. At this point, the client is expected to
	obtain a list of possible security flavors and choose what best		obtain a list of possible security flavors and choose what best
	suits its policies.		suits its policies.
	</t>		</t>
	<t>		<t>
	As mentioned, the server&apos;s security		As mentioned, the server's security
	policies will determine when a client		policies will determine when a client
	request receives NFS4ERR_WRONGSEC. See <xref		request receives NFS4ERR_WRONGSEC. See <xref target="error_op_returns
	target="error_op_returns"/> for a list of operations		" format="default"/> for a list of operations
	that can return NFS4ERR_WRONGSEC. In addition,		that can return NFS4ERR_WRONGSEC. In addition,
	when READDIR returns attributes, the rdattr_error		when READDIR returns attributes, the rdattr_error
	(<xref target="attrdef_rdattr_error" />)		(<xref target="attrdef_rdattr_error" format="default"/>)
	can contain NFS4ERR_WRONGSEC. Note that CREATE and		can contain NFS4ERR_WRONGSEC. Note that CREATE and
	REMOVE MUST NOT return NFS4ERR_WRONGSEC. The		REMOVE <bcp14>MUST NOT</bcp14> return NFS4ERR_WRONGSEC. The
	rationale for CREATE is that unless the		rationale for CREATE is that unless the
	target name exists, it cannot have a separate		target name exists, it cannot have a separate
	security policy from the parent directory,		security policy from the parent directory,
	and the security policy of the parent was		and the security policy of the parent was
	checked when its filehandle was injected into		checked when its filehandle was injected into
	the COMPOUND request's operations stream (for		the COMPOUND request's operations stream (for
	similar reasons, an OPEN operation that creates		similar reasons, an OPEN operation that creates
	the target MUST NOT return NFS4ERR_WRONGSEC). If		the target <bcp14>MUST NOT</bcp14> return NFS4ERR_WRONGSEC). If
	the target name exists, while it might have a		the target name exists, while it might have a
	separate security policy, that is irrelevant		separate security policy, that is irrelevant
	because CREATE MUST return NFS4ERR_EXIST.		because CREATE <bcp14>MUST</bcp14> return NFS4ERR_EXIST.
	The rationale for REMOVE is that while that		The rationale for REMOVE is that while that
	target might have a separate security policy, the		target might have a separate security policy, the
	target is going to be removed, and so the		target is going to be removed, and so the
	security policy of the parent trumps that of the		security policy of the parent trumps that of the
	object being removed. RENAME and LINK MAY return		object being removed. RENAME and LINK <bcp14>MAY</bcp14> return
	NFS4ERR_WRONGSEC, but the NFS4ERR_WRONGSEC error		NFS4ERR_WRONGSEC, but the NFS4ERR_WRONGSEC error
	applies only to the saved filehandle (see <xref		applies only to the saved filehandle (see <xref target="link_rename" f
	target="link_rename"/>). Any NFS4ERR_WRONGSEC		ormat="default"/>). Any NFS4ERR_WRONGSEC
	error on the current filehandle used by LINK and		error on the current filehandle used by LINK and
	RENAME MUST be returned by the PUTFH, PUTPUBFH,		RENAME <bcp14>MUST</bcp14> be returned by the PUTFH, PUTPUBFH,
	PUTROOTFH, or RESTOREFH operation that injected		PUTROOTFH, or RESTOREFH operation that injected
	the current filehandle.		the current filehandle.
	</t>		</t>
	<t>		<t>
	With the exception of LINK and RENAME,		With the exception of LINK and RENAME,
	the set of operations that can return NFS4ERR_WRONGSEC		the set of operations that can return NFS4ERR_WRONGSEC
	represents the point at which the client can inject a		represents the point at which the client can inject a
	filehandle into the "current filehandle" at the server. The		filehandle into the "current filehandle" at the server. The
	filehandle is either provided by the client (PUTFH, PUTPUBFH,		filehandle is either provided by the client (PUTFH, PUTPUBFH,
	PUTROOTFH), generated as a result of a name-to-filehandle		PUTROOTFH), generated as a result of a name-to-filehandle
	translation (LOOKUP and OPEN), or generated from the saved filehandle		translation (LOOKUP and OPEN), or generated from the saved filehandle
	via RESTOREFH. As <xref target="PUTFHplusSAVEFH"/> states,		via RESTOREFH. As <xref target="PUTFHplusSAVEFH" format="default"/> st
	a put filehandle operation followed by SAVEFH MUST NOT		ates,
			a put filehandle operation followed by SAVEFH <bcp14>MUST NOT</bcp14>
	return NFS4ERR_WRONGSEC. Thus, the RESTOREFH operation, under		return NFS4ERR_WRONGSEC. Thus, the RESTOREFH operation, under
	certain conditions (see <xref target="putfh_series"/>), is		certain conditions (see <xref target="putfh_series" format="default"/> ), is
	permitted to return NFS4ERR_WRONGSEC so that security policies		permitted to return NFS4ERR_WRONGSEC so that security policies
	can be honored.		can be honored.
	</t>		</t>
			<t>
	<t>
	The READDIR operation will not directly return the		The READDIR operation will not directly return the
	NFS4ERR_WRONGSEC error. However, if the READDIR request		NFS4ERR_WRONGSEC error. However, if the READDIR request
	included a request for attributes, it is possible that the		included a request for attributes, it is possible that the
	READDIR request&apos;s security triple did not match that of a		READDIR request's security triple did not match that of a
	directory entry. If this is the case and the client has		directory entry. If this is the case and the client has
	requested the rdattr_error attribute, the server will return the		requested the rdattr_error attribute, the server will return the
	NFS4ERR_WRONGSEC error in rdattr_error for the entry.		NFS4ERR_WRONGSEC error in rdattr_error for the entry.
	</t>		</t>
			<t>
	<t>
	To resolve an error return of		To resolve an error return of
	NFS4ERR_WRONGSEC, the client does the following:		NFS4ERR_WRONGSEC, the client does the following:
	</t>		</t>
			<ul spacing="normal">
	<t>		<li>
	<list style="symbols">
	<t>
	For LOOKUP and OPEN, the client will use SECINFO with the		For LOOKUP and OPEN, the client will use SECINFO with the
	same current filehandle and name as provided in the		same current filehandle and name as provided in the
	original LOOKUP or OPEN to enumerate the available security		original LOOKUP or OPEN to enumerate the available security
	triples.		triples.
	</t>		</li>
	<t>		<li>
	For the rdattr_error, the client will use		For the rdattr_error, the client will use
	SECINFO with the same current filehandle		SECINFO with the same current filehandle
	as provided in the original READDIR. The		as provided in the original READDIR. The
	name passed to SECINFO will be that of the		name passed to SECINFO will be that of the
	directory entry (as returned from READDIR)		directory entry (as returned from READDIR)
	that had the NFS4ERR_WRONGSEC error in the		that had the NFS4ERR_WRONGSEC error in the
	rdattr_error attribute.		rdattr_error attribute.
	</t>		</li>
	<t>		<li>
			<t>
	For PUTFH, PUTROOTFH, PUTPUBFH,		For PUTFH, PUTROOTFH, PUTPUBFH,
	RESTOREFH, LINK, and RENAME, the client will		RESTOREFH, LINK, and RENAME, the client will
	use SECINFO_NO_NAME { style =		use SECINFO_NO_NAME { style =
	SECINFO_STYLE4_CURRENT_FH }. The client		SECINFO_STYLE4_CURRENT_FH }. The client
	will prefix the SECINFO_NO_NAME operation		will prefix the SECINFO_NO_NAME operation
	with the appropriate PUTFH, PUTPUBFH,		with the appropriate PUTFH, PUTPUBFH,
	or PUTROOTFH operation that provides the		or PUTROOTFH operation that provides the
	filehandle originally provided by the PUTFH,		filehandle originally provided by the PUTFH,
	PUTPUBFH, PUTROOTFH, or RESTOREFH operation.		PUTPUBFH, PUTROOTFH, or RESTOREFH operation.
	<vspace blankLines='1' />		</t>
			<t>
	NOTE: In NFSv4.0, the client was required		NOTE: In NFSv4.0, the client was required
	to use SECINFO, and had to reconstruct the		to use SECINFO, and had to reconstruct the
	parent of the original filehandle and the		parent of the original filehandle and the
	component name of the original filehandle. The		component name of the original filehandle. The
	introduction in NFSv4.1 of SECINFO_NO_NAME		introduction in NFSv4.1 of SECINFO_NO_NAME
	obviates the need for reconstruction.		obviates the need for reconstruction.
	</t>		</t>
	<t>		</li>
			<li>
	For LOOKUPP, the client will		For LOOKUPP, the client will
	use SECINFO_NO_NAME { style =		use SECINFO_NO_NAME { style =
	SECINFO_STYLE4_PARENT } and provide the		SECINFO_STYLE4_PARENT } and provide the
	filehandle that equals the filehandle		filehandle that equals the filehandle
	originally provided to LOOKUPP.		originally provided to LOOKUPP.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
			See <xref target="SECCON" format="default"/> for a discussion on
	<t>
	See <xref target="SECCON"/> for a discussion on
	the recommendations for the security flavor used by SECINFO and		the recommendations for the security flavor used by SECINFO and
	SECINFO_NO_NAME.		SECINFO_NO_NAME.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_SETATTR" numbered="true" toc="default">
	$ -->		<name>Operation 34: SETATTR - Set Attributes</name>
	<!-- Copyright (C) The IETF Trust (2007) -->		<section toc="exclude" anchor="OP_SETATTR_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_SETATTR" title="Operation 34: SETATTR - Set Attributes" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_SETATTR_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct SETATTR4args {		struct SETATTR4args {
	/* CURRENT_FH: target object */		/* CURRENT_FH: target object */
	stateid4 stateid;		stateid4 stateid;
	fattr4 obj_attributes;		fattr4 obj_attributes;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_SETATTR_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_SETATTR_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct SETATTR4res {		struct SETATTR4res {
	nfsstat4 status;		nfsstat4 status;
	bitmap4 attrsset;		bitmap4 attrsset;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_SETATTR_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_SETATTR_DESCRIPTION" title="DESCRIPTION">
	<t>
	The SETATTR operation changes one or more of the attributes of a		The SETATTR operation changes one or more of the attributes of a
	file system object. The new attributes are specified with a bitmap and		file system object. The new attributes are specified with a bitmap and
	the attributes that follow the bitmap in bit order.		the attributes that follow the bitmap in bit order.
	</t>		</t>
	<t>		<t>
	The stateid argument for SETATTR is used to provide byte-range locking		The stateid argument for SETATTR is used to provide byte-range locking
	context that is necessary for SETATTR requests that set the size		context that is necessary for SETATTR requests that set the size
	attribute. Since setting the size attribute modifies the file's data,		attribute. Since setting the size attribute modifies the file's data,
	it has the same locking requirements as a corresponding WRITE. Any		it has the same locking requirements as a corresponding WRITE. Any
	SETATTR that sets the size attribute is incompatible with a share		SETATTR that sets the size attribute is incompatible with a share
	reservation that specifies OPEN4_SHARE_DENY_WRITE. The area between the o ld		reservation that specifies OPEN4_SHARE_DENY_WRITE. The area between the o ld
	end-of-file and the new end-of-file is considered to be modified just		end-of-file and the new end-of-file is considered to be modified just
	as would have been the case had the area in question been specified as		as would have been the case had the area in question been specified as
	the target of WRITE, for the purpose of checking conflicts with byte-range		the target of WRITE, for the purpose of checking conflicts with byte-range
	locks, for those cases in which a server is implementing mandatory		locks, for those cases in which a server is implementing mandatory
	byte-range locking behavior. A valid stateid SHOULD always be specified.		byte-range locking behavior. A valid stateid <bcp14>SHOULD</bcp14> always be specified.
	When the file size attribute is not set, the special stateid		When the file size attribute is not set, the special stateid
	consisting of all bits equal to zero MAY be passed.		consisting of all bits equal to zero <bcp14>MAY</bcp14> be passed.
	</t>		</t>
	<t>		<t>
	On either success or failure of the operation, the server will return		On either success or failure of the operation, the server will return
	the attrsset bitmask to represent what (if any) attributes were		the attrsset bitmask to represent what (if any) attributes were
	successfully set. The attrsset in the response is a subset of the		successfully set. The attrsset in the response is a subset of the
	attrmask field of the obj_attributes field in the argument.		attrmask field of the obj_attributes field in the argument.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_SETATTR_IMPLEMENTATION" title="IMPLEMENTATIO		<section toc="exclude" anchor="OP_SETATTR_IMPLEMENTATION" numbered="true
	N">		">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	If the request specifies the owner attribute to be set, the server		If the request specifies the owner attribute to be set, the server
	SHOULD allow the operation to succeed if the current owner of the		<bcp14>SHOULD</bcp14> allow the operation to succeed if the current owner of the
	object matches the value specified in the request. Some servers may		object matches the value specified in the request. Some servers may
	be implemented in a way as to prohibit the setting of the owner		be implemented in a way as to prohibit the setting of the owner
	attribute unless the requester has privilege to do so. If the server		attribute unless the requester has privilege to do so. If the server
	is lenient in this one case of matching owner values, the client		is lenient in this one case of matching owner values, the client
	implementation may be simplified in cases of creation of an object		implementation may be simplified in cases of creation of an object
	(e.g., an exclusive create via OPEN)		(e.g., an exclusive create via OPEN)
	followed by a SETATTR.		followed by a SETATTR.
	</t>		</t>
	<t>		<t>
	The file size attribute is used to request changes		The file size attribute is used to request changes
	to the size of a file. A value of zero causes the		to the size of a file. A value of zero causes the
	file to be truncated, a value less than the current		file to be truncated, a value less than the current
	size of the file causes data from new size to the		size of the file causes data from new size to the
	end of the file to be discarded, and a size greater		end of the file to be discarded, and a size greater
	than the current size of the file causes logically		than the current size of the file causes logically
	zeroed data bytes to be added to the end of the		zeroed data bytes to be added to the end of the
	file. Servers are free to implement this using		file. Servers are free to implement this using
	unallocated bytes (holes) or allocated data bytes		unallocated bytes (holes) or allocated data bytes
	set to zero. Clients should not make any assumptions		set to zero. Clients should not make any assumptions
	regarding a server's implementation of this feature,		regarding a server's implementation of this feature,
	beyond that the bytes in the affected byte-range returned by		beyond that the bytes in the affected byte-range returned by
	READ will be zeroed. Servers MUST support extending		READ will be zeroed. Servers <bcp14>MUST</bcp14> support extending
	the file size via SETATTR.		the file size via SETATTR.
	</t>		</t>
	<t>		<t>
	SETATTR is not guaranteed to be atomic. A failed SETATTR may partially		SETATTR is not guaranteed to be atomic. A failed SETATTR may partially
	change a file's attributes, hence the reason why the reply always		change a file's attributes, hence the reason why the reply always
	includes the status and the list of attributes that were set.		includes the status and the list of attributes that were set.
	</t>		</t>
	<t>		<t>
	If the object whose attributes are being changed has a file delegation		If the object whose attributes are being changed has a file delegation
	that is held by a client other than the one doing the SETATTR,		that is held by a client other than the one doing the SETATTR,
	the delegation(s) must be recalled, and the		the delegation(s) must be recalled, and the
	operation cannot proceed to actually change an attribute		operation cannot proceed to actually change an attribute
	until each such delegation is returned		until each such delegation is returned
	or revoked.		or revoked.
	In all cases in which delegations are recalled, the server		In all cases in which delegations are recalled, the server
	is likely to return one or more NFS4ERR_DELAY errors while the		is likely to return one or more NFS4ERR_DELAY errors while the
	delegation(s) remains outstanding, although it might not do that if the		delegation(s) remains outstanding, although it might not do that if the
	delegations are returned quickly.		delegations are returned quickly.
	</t>		</t>
	<t>		<t>
	If the object whose attributes are being set is a directory		If the object whose attributes are being set is a directory
	and another client holds a directory delegation for that		and another client holds a directory delegation for that
	directory, then if enabled, asynchronous notifications will be generated		directory, then if enabled, asynchronous notifications will be generated
	when the set of attributes changed has a non-null intersection		when the set of attributes changed has a non-null intersection
	with the set of attributes for which notification is requested.		with the set of attributes for which notification is requested.
	Notifications of type NOTIFY4_CHANGE_DIR_ATTRS will be sent to		Notifications of type NOTIFY4_CHANGE_DIR_ATTRS will be sent to
	the appropriate client(s), but the SETATTR is not delayed by		the appropriate client(s), but the SETATTR is not delayed by
	waiting for these notifications to be sent.		waiting for these notifications to be sent.
	</t>		</t>
	<t>		<t>
	If the object whose attributes are being set is a member of		If the object whose attributes are being set is a member of
	the directory for which another client holds a directory delegation,		the directory for which another client holds a directory delegation,
	then asynchronous notifications will be generated		then asynchronous notifications will be generated
	when the set of attributes changed has a non-null intersection		when the set of attributes changed has a non-null intersection
	with the set of attributes for which notification is requested.		with the set of attributes for which notification is requested.
	Notifications of type NOTIFY4_CHANGE_CHILD_ATTRS will be sent to		Notifications of type NOTIFY4_CHANGE_CHILD_ATTRS will be sent to
	the appropriate clients, but the SETATTR is not delayed by		the appropriate clients, but the SETATTR is not delayed by
	waiting for these notifications to be sent.		waiting for these notifications to be sent.
	</t>		</t>
	<t>		<t>
	Changing the size of a file with SETATTR indirectly		Changing the size of a file with SETATTR indirectly
	changes the time_modify and change attributes.		changes the time_modify and change attributes.
	A client must account for this as size changes can		A client must account for this as size changes can
	result in data deletion.		result in data deletion.
	</t>		</t>
	<t>		<t>
	The attributes time_access_set and time_modify_set are write-only		The attributes time_access_set and time_modify_set are write-only
	attributes constructed as a switched union so the client can direct		attributes constructed as a switched union so the client can direct
	the server in setting the time values. If the switched union		the server in setting the time values. If the switched union
	specifies SET_TO_CLIENT_TIME4, the client has provided an nfstime4 to		specifies SET_TO_CLIENT_TIME4, the client has provided an nfstime4 to
	be used for the operation. If the switch union does not specify		be used for the operation. If the switch union does not specify
	SET_TO_CLIENT_TIME4, the server is to use its current time for the		SET_TO_CLIENT_TIME4, the server is to use its current time for the
	SETATTR operation.		SETATTR operation.
	</t>		</t>
	<t>		<t>
	If server and client times differ, programs that compare client time		If server and client times differ, programs that compare client time
	to file times can break. A time synchronization protocol should be used to		to file times can break. A time synchronization protocol should be used to
	limit client/server time skew.		limit client/server time skew.
	</t>		</t>
	<t>		<t>
	Use of a COMPOUND containing a VERIFY operation specifying only the		Use of a COMPOUND containing a VERIFY operation specifying only the
	change attribute, immediately followed by a SETATTR, provides a means		change attribute, immediately followed by a SETATTR, provides a means
	whereby a client may specify a request that emulates the functionality		whereby a client may specify a request that emulates the functionality
	of the SETATTR guard mechanism of NFSv3. Since the function		of the SETATTR guard mechanism of NFSv3. Since the function
	of the guard mechanism is to avoid changes to the file attributes		of the guard mechanism is to avoid changes to the file attributes
	based on stale information, delays between checking of the guard		based on stale information, delays between checking of the guard
	condition and the setting of the attributes have the potential to		condition and the setting of the attributes have the potential to
	compromise this function, as would the corresponding delay in the		compromise this function, as would the corresponding delay in the
	NFSv4 emulation. Therefore, NFSv4.1 servers SHOULD take		NFSv4 emulation. Therefore, NFSv4.1 servers <bcp14>SHOULD</bcp14> take
	care to avoid such delays, to the degree possible, when executing such		care to avoid such delays, to the degree possible, when executing such
	a request.		a request.
	</t>		</t>
	<t>		<t>
	If the server does not support an attribute as requested by the		If the server does not support an attribute as requested by the
	client, the server SHOULD return NFS4ERR_ATTRNOTSUPP.		client, the server <bcp14>SHOULD</bcp14> return NFS4ERR_ATTRNOTSUPP.
	</t>		</t>
	<t>		<t>
	A mask of the attributes actually set is returned by SETATTR in all		A mask of the attributes actually set is returned by SETATTR in all
	cases. That mask MUST NOT include attribute bits not requested to be		cases. That mask <bcp14>MUST NOT</bcp14> include attribute bits not reque sted to be
	set by the client.		set by the client.
	If the attribute masks in the request and		If the attribute masks in the request and
	reply are equal, the status field in the reply MUST be NFS4_OK.		reply are equal, the status field in the reply <bcp14>MUST</bcp14> be NFS4
	</t>		_OK.
	</section>		</t>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		</section>
	$ -->		<section anchor="OP_VERIFY" numbered="true" toc="default">
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<name>Operation 37: VERIFY - Verify Same Attributes</name>
	<!-- Copyright (C) The Internet Society (2006) -->		<section toc="exclude" anchor="OP_VERIFY_ARGUMENTS" numbered="true">
	<section anchor="OP_VERIFY" title="Operation 37: VERIFY - Verify Same Attributes		<name>ARGUMENTS</name>
	" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_VERIFY_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	struct VERIFY4args {		struct VERIFY4args {
	/* CURRENT_FH: object */		/* CURRENT_FH: object */
	fattr4 obj_attributes;		fattr4 obj_attributes;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_VERIFY_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_VERIFY_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct VERIFY4res {		struct VERIFY4res {
	nfsstat4 status;		nfsstat4 status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_VERIFY_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_VERIFY_DESCRIPTION" title="DESCRIPTION">
	<t>
	The VERIFY operation is used to verify that attributes have the value		The VERIFY operation is used to verify that attributes have the value
	assumed by the client before proceeding with the following operations in		assumed by the client before proceeding with the following operations in
	the COMPOUND request. If any of the attributes do not match, then the		the COMPOUND request. If any of the attributes do not match, then the
	error NFS4ERR_NOT_SAME must be returned. The current filehandle		error NFS4ERR_NOT_SAME must be returned. The current filehandle
	retains its value after successful completion of the operation.		retains its value after successful completion of the operation.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_VERIFY_IMPLEMENTATION" title="IMPLEMENTATION		<section toc="exclude" anchor="OP_VERIFY_IMPLEMENTATION" numbered="true"
	">		>
	<t>		<name>IMPLEMENTATION</name>
			<t>
	One possible use of the VERIFY operation is the following series		One possible use of the VERIFY operation is the following series
	of operations. With this, the client is attempting to verify that the file		of operations. With this, the client is attempting to verify that the file
	being removed will match what the client expects to be removed. This		being removed will match what the client expects to be removed. This
	series can help prevent the unintended deletion of a file.		series can help prevent the unintended deletion of a file.
	<figure>		</t>
	<artwork>		<sourcecode type="xdr"><![CDATA[
	PUTFH (directory filehandle)		PUTFH (directory filehandle)
	LOOKUP (file name)		LOOKUP (file name)
	VERIFY (filehandle == fh)		VERIFY (filehandle == fh)
	PUTFH (directory filehandle)		PUTFH (directory filehandle)
	REMOVE (file name)		REMOVE (file name)]]></sourcecode>
	</artwork>		<t>
	</figure>
	This series does not prevent a second client from removing and		This series does not prevent a second client from removing and
	creating a new file in the middle of this sequence, but it does help		creating a new file in the middle of this sequence, but it does help
	avoid the unintended result.		avoid the unintended result.
	</t>		</t>
	<t>		<t>
	In the case that a RECOMMENDED attribute is specified in the VERIFY		In the case that a <bcp14>RECOMMENDED</bcp14> attribute is specified in th
			e VERIFY
	operation and the server does not support that attribute for the		operation and the server does not support that attribute for the
	file system object, the error NFS4ERR_ATTRNOTSUPP is returned to the		file system object, the error NFS4ERR_ATTRNOTSUPP is returned to the
	client.		client.
	</t>		</t>
	<t>		<t>
	When the attribute rdattr_error or any set-only attribute (e.g.,		When the attribute rdattr_error or any set-only attribute (e.g.,
	time_modify_set) is specified, the error NFS4ERR_INVAL is returned to		time_modify_set) is specified, the error NFS4ERR_INVAL is returned to
	the client.		the client.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_WRITE" numbered="true" toc="default">
	$ -->		<name>Operation 38: WRITE - Write to File</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_WRITE_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="OP_WRITE" title="Operation 38: WRITE - Write to File" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_WRITE_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	enum stable_how4 {		enum stable_how4 {
	UNSTABLE4 = 0,		UNSTABLE4 = 0,
	DATA_SYNC4 = 1,		DATA_SYNC4 = 1,
	FILE_SYNC4 = 2		FILE_SYNC4 = 2
	};		};
	struct WRITE4args {		struct WRITE4args {
	/* CURRENT_FH: file */		/* CURRENT_FH: file */
	stateid4 stateid;		stateid4 stateid;
	offset4 offset;		offset4 offset;
	stable_how4 stable;		stable_how4 stable;
	opaque data&lt;>;		opaque data<>;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_WRITE_RESULTS" numbered="true">
	</figure>		<name>RESULTS</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_WRITE_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct WRITE4resok {		struct WRITE4resok {
	count4 count;		count4 count;
	stable_how4 committed;		stable_how4 committed;
	verifier4 writeverf;		verifier4 writeverf;
	};		};
	union WRITE4res switch (nfsstat4 status) {		union WRITE4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	WRITE4resok resok4;		WRITE4resok resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_WRITE_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_WRITE_DESCRIPTION" title="DESCRIPTION">
	<t>
	The WRITE operation is used to write data to a regular file. The		The WRITE operation is used to write data to a regular file. The
	target file is specified by the current filehandle. The offset		target file is specified by the current filehandle. The offset
	specifies the offset where the data should be written. An offset of zero		specifies the offset where the data should be written. An offset of zero
	specifies that the write should start at the beginning of the		specifies that the write should start at the beginning of the
	file. The count, as encoded as part of the opaque data parameter,		file. The count, as encoded as part of the opaque data parameter,
	represents the number of bytes of data that are to be written. If the		represents the number of bytes of data that are to be written. If the
	count is zero, the WRITE will succeed and return a count of zero subject t o permissions checking. The server MAY		count is zero, the WRITE will succeed and return a count of zero subject t o permissions checking. The server <bcp14>MAY</bcp14>
	write fewer bytes than requested by the client.		write fewer bytes than requested by the client.
	</t>		</t>
	<t>		<t>
	The client specifies with the stable parameter the method		The client specifies with the stable parameter the method
	of how the data is to be processed by the server. If stable is		of how the data is to be processed by the server. If stable is
	FILE_SYNC4, the server MUST commit the data written plus all		FILE_SYNC4, the server <bcp14>MUST</bcp14> commit the data written plus al l
	file system metadata to stable storage before returning results. This		file system metadata to stable storage before returning results. This
	corresponds to the NFSv2 protocol semantics. Any other		corresponds to the NFSv2 protocol semantics. Any other
	behavior constitutes a protocol violation. If stable is DATA_SYNC4,		behavior constitutes a protocol violation. If stable is DATA_SYNC4,
	then the server MUST commit all of the data to stable storage and		then the server <bcp14>MUST</bcp14> commit all of the data to stable stora ge and
	enough of the metadata to retrieve the data before returning. The		enough of the metadata to retrieve the data before returning. The
	server implementor is free to implement DATA_SYNC4 in the same fashion		server implementor is free to implement DATA_SYNC4 in the same fashion
	as FILE_SYNC4, but with a possible performance drop. If stable is		as FILE_SYNC4, but with a possible performance drop. If stable is
	UNSTABLE4, the server is free to commit any part of the data and the		UNSTABLE4, the server is free to commit any part of the data and the
	metadata to stable storage, including all or none, before returning a		metadata to stable storage, including all or none, before returning a
	reply to the client. There is no guarantee whether or when any		reply to the client. There is no guarantee whether or when any
	uncommitted data will subsequently be committed to stable storage. The		uncommitted data will subsequently be committed to stable storage. The
	only guarantees made by the server are that it will not destroy any		only guarantees made by the server are that it will not destroy any
	data without changing the value of writeverf and that it will not commit		data without changing the value of writeverf and that it will not commit
	the data and metadata at a level less than that requested by the		the data and metadata at a level less than that requested by the
	client.		client.
	</t>		</t>
	<t>		<t>
	Except when special stateids are used, the		Except when special stateids are used, the
	stateid value for a WRITE request represents a value returned from		stateid value for a WRITE request represents a value returned from
	a previous byte-range LOCK or OPEN request or the stateid		a previous byte-range LOCK or OPEN request or the stateid
	associated with a delegation. The stateid identifies the associated		associated with a delegation. The stateid identifies the associated
	owners if any and is		owners if any and is
	used by the server to verify that the associated locks are still		used by the server to verify that the associated locks are still
	valid (e.g., have not been revoked).		valid (e.g., have not been revoked).
	</t>		</t>
	<t>		<t>
	Upon successful completion, the following results are returned. The		Upon successful completion, the following results are returned. The
	count result is the number of bytes of data written to the file. The		count result is the number of bytes of data written to the file. The
	server may write fewer bytes than requested. If so, the actual number		server may write fewer bytes than requested. If so, the actual number
	of bytes written starting at location, offset, is returned.		of bytes written starting at location, offset, is returned.
	</t>		</t>
	<t>		<t>
	The server also returns an indication of the level of commitment of		The server also returns an indication of the level of commitment of
	the data and metadata via committed.		the data and metadata via committed.
	Per <xref target="stable_committed"/>,		Per <xref target="stable_committed" format="default"/>,
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
	The server MAY commit the data at a stronger level		<li>
			The server <bcp14>MAY</bcp14> commit the data at a stronger level
	than requested.		than requested.
	</t>		</li>
			<li>
	<t>		The server <bcp14>MUST</bcp14> commit the data at a level at
	The server MUST commit the data at a level at
	least as high as that committed.		least as high as that committed.
	</t>		</li>
	</list>		</ul>
	</t>
	<texttable anchor="stable_committed">
	<preamble>
	Valid combinations of the fields stable in the request and committed in
	the reply.
	</preamble>
	<ttcol>stable</ttcol>
	<ttcol>committed</ttcol>
	<c>UNSTABLE4</c> <c>FILE_SYNC4, DATA_SYNC4, UNSTABLE4</c>
	<c>DATA_SYNC4</c> <c>FILE_SYNC4, DATA_SYNC4</c>
	<c>FILE_SYNC4</c> <c>FILE_SYNC4</c>
	</texttable>
	<t>		<table anchor="stable_committed" align="center">
			<name>Valid Combinations of the Fields Stable in the Request and Commi
			tted in the Reply</name>
			<thead>
			<tr>
			<th align="left">stable</th>
			<th align="left">committed</th>
			</tr>
			</thead>
			<tbody>
			<tr>
			<td align="left">UNSTABLE4</td>
			<td align="left">FILE_SYNC4, DATA_SYNC4, UNSTABLE4</td>
			</tr>
			<tr>
			<td align="left">DATA_SYNC4</td>
			<td align="left">FILE_SYNC4, DATA_SYNC4</td>
			</tr>
			<tr>
			<td align="left">FILE_SYNC4</td>
			<td align="left">FILE_SYNC4</td>
			</tr>
			</tbody>
			</table>
			<t>
	The final portion of the result is the field		The final portion of the result is the field
	writeverf. This field is the write verifier and is a		writeverf. This field is the write verifier and is a
	cookie that the client can use to determine whether		cookie that the client can use to determine whether
	a server has changed instance state (e.g., server		a server has changed instance state (e.g., server
	restart) between a call to WRITE and a subsequent		restart) between a call to WRITE and a subsequent
	call to either WRITE or COMMIT. This cookie MUST be		call to either WRITE or COMMIT. This cookie <bcp14>MUST</bcp14> be
	unchanged during a single instance of the NFSv4.1		unchanged during a single instance of the NFSv4.1
	server and MUST be unique between instances of the		server and <bcp14>MUST</bcp14> be unique between instances of the
	NFSv4.1 server. If the cookie changes, then the		NFSv4.1 server. If the cookie changes, then the
	client MUST assume that any data written with an		client <bcp14>MUST</bcp14> assume that any data written with an
	UNSTABLE4 value for committed and an old writeverf in the reply		UNSTABLE4 value for committed and an old writeverf in the reply
	has been lost and will need to be recovered.		has been lost and will need to be recovered.
	</t>		</t>
	<t>		<t>
	If a client writes data to the server with the stable argument set to		If a client writes data to the server with the stable argument set to
	UNSTABLE4 and the reply yields a committed response of DATA_SYNC4 or		UNSTABLE4 and the reply yields a committed response of DATA_SYNC4 or
	UNSTABLE4, the client will follow up some time in the future with a		UNSTABLE4, the client will follow up some time in the future with a
	COMMIT operation to synchronize outstanding asynchronous data and		COMMIT operation to synchronize outstanding asynchronous data and
	metadata with the server's stable storage, barring client error. It is		metadata with the server's stable storage, barring client error. It is
	possible that due to client crash or other error that a subsequent		possible that due to client crash or other error that a subsequent
	COMMIT will not be received by the server.		COMMIT will not be received by the server.
	</t>		</t>
	<t>		<t>
	For a WRITE with a stateid value of all bits equal to zero, the server MAY		For a WRITE with a stateid value of all bits equal to zero, the server <bc
	allow		p14>MAY</bcp14> allow
	the WRITE to be serviced subject to mandatory byte-range locks or the		the WRITE to be serviced subject to mandatory byte-range locks or the
	current share deny modes for the file. For a WRITE with a stateid		current share deny modes for the file. For a WRITE with a stateid
	value of all bits equal to 1, the server MUST NOT allow the WRITE operatio n to		value of all bits equal to 1, the server <bcp14>MUST NOT</bcp14> allow the WRITE operation to
	bypass locking checks at the server and otherwise is		bypass locking checks at the server and otherwise is
	treated as if a stateid of all bits equal to zero were used.		treated as if a stateid of all bits equal to zero were used.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_WRITE_IMPLEMENTATION" title="IMPLEMENTATION"		<section toc="exclude" anchor="OP_WRITE_IMPLEMENTATION" numbered="true">
	>		<name>IMPLEMENTATION</name>
	<t>		<t>
	It is possible for the server to write fewer bytes of data than		It is possible for the server to write fewer bytes of data than
	requested by the client. In this case, the server SHOULD NOT return		requested by the client. In this case, the server <bcp14>SHOULD NOT</bcp1 4> return
	an error unless no data was written at all. If the server writes less		an error unless no data was written at all. If the server writes less
	than the number of bytes specified, the client will need to send another		than the number of bytes specified, the client will need to send another
	WRITE to write the remaining data.		WRITE to write the remaining data.
	</t>		</t>
	<t>		<t>
	It is assumed that the act of writing data to		It is assumed that the act of writing data to
	a file will cause the time_modified and change		a file will cause the time_modified and change
	attributes of the file to be updated. However,		attributes of the file to be updated. However,
	these attributes SHOULD NOT be changed		these attributes <bcp14>SHOULD NOT</bcp14> be changed
	unless the contents of the file are changed. Thus,		unless the contents of the file are changed. Thus,
	a WRITE request with count set to zero SHOULD NOT cause		a WRITE request with count set to zero <bcp14>SHOULD NOT</bcp14> cause
	the time_modified and change attributes of the file to be updated.		the time_modified and change attributes of the file to be updated.
	</t>		</t>
	<t>		<t>
	Stable storage is persistent storage that survives:		Stable storage is persistent storage that survives:
	</t>		</t>
	<t>		<ol spacing="normal" type="1">
	<list style="numbers">		<li>
	<t>
	Repeated power failures.		Repeated power failures.
	</t>		</li>
	<t>		<li>
	Hardware failures (of any board, power supply, etc.).		Hardware failures (of any board, power supply, etc.).
	</t>		</li>
	<t>		<li>
	Repeated software crashes and restarts.		Repeated software crashes and restarts.
	</t>		</li>
	</list>		</ol>
	</t>		<t>
	<t>
	This definition does not address failure of the stable storage module		This definition does not address failure of the stable storage module
	itself.		itself.
	</t>		</t>
	<t>		<t>
	The verifier is defined to allow a client to detect		The verifier is defined to allow a client to detect
	different instances of an NFSv4.1 protocol server		different instances of an NFSv4.1 protocol server
	over which cached, uncommitted data may be lost. In		over which cached, uncommitted data may be lost. In
	the most likely case, the verifier allows the client		the most likely case, the verifier allows the client
	to detect server restarts. This information is		to detect server restarts. This information is
	required so that the client can safely determine		required so that the client can safely determine
	whether the server could have lost cached data.		whether the server could have lost cached data.
	If the server fails unexpectedly and the client has		If the server fails unexpectedly and the client has
	uncommitted data from previous WRITE requests (done		uncommitted data from previous WRITE requests (done
	with the stable argument set to UNSTABLE4 and in		with the stable argument set to UNSTABLE4 and in
	which the result committed was returned as UNSTABLE4		which the result committed was returned as UNSTABLE4
	as well), the server might not have flushed cached		as well), the server might not have flushed cached
	data to stable storage. The burden of recovery is		data to stable storage. The burden of recovery is
	on the client, and the client will need to retransmit		on the client, and the client will need to retransmit
	the data to the server.		the data to the server.
	</t>		</t>
	<t>		<t>
	A suggested verifier would be to use the time that		A suggested verifier would be to use the time that
	the server was last started (if restarting the server		the server was last started (if restarting the server
	results in lost buffers).		results in lost buffers).
	</t>		</t>
	<t>		<t>
	The reply's committed field allows the client to do more		The reply's committed field allows the client to do more
	effective caching. If the server is committing all WRITE requests to		effective caching. If the server is committing all WRITE requests to
	stable storage, then it SHOULD return with committed set to FILE_SYNC4,		stable storage, then it <bcp14>SHOULD</bcp14> return with committed set to FILE_SYNC4,
	regardless of the value of the stable field in the arguments. A server		regardless of the value of the stable field in the arguments. A server
	that uses an NVRAM accelerator may choose to implement this policy.		that uses an NVRAM accelerator may choose to implement this policy.
	The client can use this to increase the effectiveness of the cache by		The client can use this to increase the effectiveness of the cache by
	discarding cached data that has already been committed on the server.		discarding cached data that has already been committed on the server.
	</t>		</t>
	<t>		<t>
	Some implementations may return NFS4ERR_NOSPC instead		Some implementations may return NFS4ERR_NOSPC instead
	of NFS4ERR_DQUOT when a user's quota is exceeded.		of NFS4ERR_DQUOT when a user's quota is exceeded.
	</t>		</t>
	<t>		<t>
	In the case that the current filehandle is of		In the case that the current filehandle is of
	type NF4DIR, the server will return NFS4ERR_ISDIR.		type NF4DIR, the server will return NFS4ERR_ISDIR.
	If the current file is a symbolic link, the error		If the current file is a symbolic link, the error
	NFS4ERR_SYMLINK will be returned. Otherwise, if the		NFS4ERR_SYMLINK will be returned. Otherwise, if the
	current filehandle does not designate an ordinary		current filehandle does not designate an ordinary
	file, the server will return NFS4ERR_WRONG_TYPE.		file, the server will return NFS4ERR_WRONG_TYPE.
	</t>		</t>
	<t>		<t>
	If mandatory byte-range locking is in effect for the file,		If mandatory byte-range locking is in effect for the file,
	and the corresponding byte-range of the data to		and the corresponding byte-range of the data to
	be written to the file is READ_LT or WRITE_LT locked by		be written to the file is READ_LT or WRITE_LT locked by
	an owner that is not associated with the stateid,		an owner that is not associated with the stateid,
	the server MUST return NFS4ERR_LOCKED. If so,		the server <bcp14>MUST</bcp14> return NFS4ERR_LOCKED. If so,
	the client MUST check if the owner corresponding		the client <bcp14>MUST</bcp14> check if the owner corresponding
	to the stateid used with the WRITE operation has a		to the stateid used with the WRITE operation has a
	conflicting READ_LT lock that overlaps with the byte-range		conflicting READ_LT lock that overlaps with the byte-range
	that was to be written. If the stateid's owner has		that was to be written. If the stateid's owner has
	no conflicting READ_LT lock, then the client SHOULD try		no conflicting READ_LT lock, then the client <bcp14>SHOULD</bcp14> try
	to get the appropriate write byte-range lock via the		to get the appropriate write byte-range lock via the
	LOCK operation before re-attempting the WRITE. When		LOCK operation before re-attempting the WRITE. When
	the WRITE completes, the client SHOULD release the		the WRITE completes, the client <bcp14>SHOULD</bcp14> release the
	byte-range lock via LOCKU.		byte-range lock via LOCKU.
	</t>		</t>
	<t>		<t>
	If the stateid's owner had a conflicting READ_LT lock, then the client		If the stateid's owner had a conflicting READ_LT lock, then the client
	has no choice but to return an error to the application that attempted		has no choice but to return an error to the application that attempted
	the WRITE. The reason is that since the stateid's owner had a READ_LT		the WRITE. The reason is that since the stateid's owner had a READ_LT
	lock, either the server attempted to temporarily effectively upgrade		lock, either the server attempted to temporarily effectively upgrade
	this READ_LT lock to a WRITE_LT lock or the server has no upgrade		this READ_LT lock to a WRITE_LT lock or the server has no upgrade
	capability. If the server attempted to upgrade the READ_LT lock and		capability. If the server attempted to upgrade the READ_LT lock and
	failed, it is pointless for the client to re-attempt the upgrade via		failed, it is pointless for the client to re-attempt the upgrade via
	the LOCK operation, because there might be another client also trying		the LOCK operation, because there might be another client also trying
	to upgrade. If two clients are blocked trying to upgrade the same lock,		to upgrade. If two clients are blocked trying to upgrade the same lock,
	the clients deadlock. If the server has no upgrade capability, then		the clients deadlock. If the server has no upgrade capability, then
	it is pointless to try a LOCK operation to upgrade.		it is pointless to try a LOCK operation to upgrade.
	</t>		</t>
	<t>		<t>
	If one or more other clients have delegations for the file being		If one or more other clients have delegations for the file being
	written, those delegations MUST be recalled, and the		written, those delegations <bcp14>MUST</bcp14> be recalled, and the
	operation cannot proceed until those delegations are returned		operation cannot proceed until those delegations are returned
	or revoked. Except where this		or revoked. Except where this
	happens very quickly, one or more NFS4ERR_DELAY errors will be		happens very quickly, one or more NFS4ERR_DELAY errors will be
	returned to requests made while the delegation remains outstanding.		returned to requests made while the delegation remains outstanding.
	Normally, delegations will not be recalled as a result of a WRITE		Normally, delegations will not be recalled as a result of a WRITE
	operation since the recall will occur as a result of an earlier		operation since the recall will occur as a result of an earlier
	OPEN. However, since it is possible for a WRITE to be done with		OPEN. However, since it is possible for a WRITE to be done with
	a special stateid, the server needs to check for this case even		a special stateid, the server needs to check for this case even
	though the client should have done an OPEN previously.		though the client should have done an OPEN previously.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_BACKCHANNEL_CTL" numbered="true" toc="default">
	$ -->		<name>Operation 40: BACKCHANNEL_CTL - Backchannel Control</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_BACKCHANNEL_CTL_ARGUMENT" numbered="tr
	<!-- Copyright (C) The Internet Society (2006) -->		ue">
	<section anchor="OP_BACKCHANNEL_CTL" title="Operation 40: BACKCHANNEL_CTL - Back		<name>ARGUMENT</name>
	channel Control" >		<sourcecode type="xdr"><![CDATA[
			typedef opaque gsshandle4_t<>;
	<section toc="exclude" anchor="OP_BACKCHANNEL_CTL_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	typedef opaque gsshandle4_t&lt;>;
	struct gss_cb_handles4 {		struct gss_cb_handles4 {
	rpc_gss_svc_t gcbp_service; /* RFC 2203 */		rpc_gss_svc_t gcbp_service; /* RFC 2203 */
	gsshandle4_t gcbp_handle_from_server;		gsshandle4_t gcbp_handle_from_server;
	gsshandle4_t gcbp_handle_from_client;		gsshandle4_t gcbp_handle_from_client;
	};		};
	union callback_sec_parms4 switch (uint32_t cb_secflavor) {		union callback_sec_parms4 switch (uint32_t cb_secflavor) {
	case AUTH_NONE:		case AUTH_NONE:
	void;		void;
	case AUTH_SYS:		case AUTH_SYS:
	authsys_parms cbsp_sys_cred; /* RFC 1831 */		authsys_parms cbsp_sys_cred; /* RFC 5531 */
	case RPCSEC_GSS:		case RPCSEC_GSS:
	gss_cb_handles4 cbsp_gss_handles;		gss_cb_handles4 cbsp_gss_handles;
	};		};
	struct BACKCHANNEL_CTL4args {		struct BACKCHANNEL_CTL4args {
	uint32_t bca_cb_program;		uint32_t bca_cb_program;
	callback_sec_parms4 bca_sec_parms&lt;>;		callback_sec_parms4 bca_sec_parms<>;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_BACKCHANNEL_CTL_RESULT" numbered="true
	</figure>		">
	</section>		<name>RESULT</name>
	<section toc="exclude" anchor="OP_BACKCHANNEL_CTL_RESULT" title="RESULT">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct BACKCHANNEL_CTL4res {		struct BACKCHANNEL_CTL4res {
	nfsstat4 bcr_status;		nfsstat4 bcr_status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_BACKCHANNEL_CTL_DESCRIPTION" numbered=
	</figure>		"true">
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_BACKCHANNEL_CTL_DESCRIPTION" title="DESCRIPT		<t>
	ION">
	<t>
	The BACKCHANNEL_CTL operation replaces the		The BACKCHANNEL_CTL operation replaces the
	backchannel's callback program number and adds		backchannel's callback program number and adds
	(not replaces) RPCSEC_GSS handles for use by the		(not replaces) RPCSEC_GSS handles for use by the
	backchannel.		backchannel.
	</t>		</t>
	<t>		<t>
	The arguments of the BACKCHANNEL_CTL call are		The arguments of the BACKCHANNEL_CTL call are
	a subset of the CREATE_SESSION parameters.		a subset of the CREATE_SESSION parameters.
	In the arguments of BACKCHANNEL_CTL, the		In the arguments of BACKCHANNEL_CTL, the
	bca_cb_program field and bca_sec_parms fields		bca_cb_program field and bca_sec_parms fields
	correspond respectively to the csa_cb_program and		correspond respectively to the csa_cb_program and
	csa_sec_parms fields of the arguments of CREATE_SESSION		csa_sec_parms fields of the arguments of CREATE_SESSION
	(<xref target="OP_CREATE_SESSION"/>).		(<xref target="OP_CREATE_SESSION" format="default"/>).
	</t>		</t>
	<t>		<t>
	BACKCHANNEL_CTL MUST appear in a COMPOUND that starts		BACKCHANNEL_CTL <bcp14>MUST</bcp14> appear in a COMPOUND that starts
	with SEQUENCE.		with SEQUENCE.
	</t>		</t>
	<t>		<t>
	If the RPCSEC_GSS handle identified by		If the RPCSEC_GSS handle identified by
	gcbp_handle_from_server does not exist on the server,		gcbp_handle_from_server does not exist on the server,
	the server MUST return NFS4ERR_NOENT.		the server <bcp14>MUST</bcp14> return NFS4ERR_NOENT.
	</t>		</t>
			<t>
	<t>		If an RPCSEC_GSS handle is using the SSV context (see <xref target="ssv_m
	If an RPCSEC_GSS handle is using the SSV context (see <xref		ech" format="default"/>), then because each SSV RPCSEC_GSS
	target="ssv_mech"/>), then because each SSV RPCSEC_GSS
	handle shares a common SSV GSS context, there are security		handle shares a common SSV GSS context, there are security
	considerations specific to this situation discussed in <xref		considerations specific to this situation discussed in <xref target="rpcs
	target="rpcsec_ssv_consider"/>.		ec_ssv_consider" format="default"/>.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		<section anchor="OP_BIND_CONN_TO_SESSION" numbered="true" toc="default">
			<name>Operation 41: BIND_CONN_TO_SESSION - Associate Connection with Ses
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		sion</name>
	$ -->		<section toc="exclude" anchor="OP_BIND_CONN_TO_SESSION_ARGUMENT" numbere
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		d="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_BIND_CONN_TO_SESSION" title="Operation 41: BIND_CONN_TO_SESS		<sourcecode type="xdr"><![CDATA[
	ION - Associate Connection with Session" >
	<section toc="exclude"
	anchor="OP_BIND_CONN_TO_SESSION_ARGUMENT"
	title="ARGUMENT">
	<figure>
	<artwork>
	enum channel_dir_from_client4 {		enum channel_dir_from_client4 {
	CDFC4_FORE = 0x1,		CDFC4_FORE = 0x1,
	CDFC4_BACK = 0x2,		CDFC4_BACK = 0x2,
	CDFC4_FORE_OR_BOTH = 0x3,		CDFC4_FORE_OR_BOTH = 0x3,
	CDFC4_BACK_OR_BOTH = 0x7		CDFC4_BACK_OR_BOTH = 0x7
	};		};
	struct BIND_CONN_TO_SESSION4args {		struct BIND_CONN_TO_SESSION4args {
	sessionid4 bctsa_sessid;		sessionid4 bctsa_sessid;
	channel_dir_from_client4		channel_dir_from_client4
	bctsa_dir;		bctsa_dir;
	bool bctsa_use_conn_in_rdma_mode;		bool bctsa_use_conn_in_rdma_mode;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_BIND_CONN_TO_SESSION_RESULT" numbered=
	</figure>		"true">
	</section>		<name>RESULT</name>
	<section toc="exclude" anchor="OP_BIND_CONN_TO_SESSION_RESULT" title="RESULT">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	enum channel_dir_from_server4 {		enum channel_dir_from_server4 {
	CDFS4_FORE = 0x1,		CDFS4_FORE = 0x1,
	CDFS4_BACK = 0x2,		CDFS4_BACK = 0x2,
	CDFS4_BOTH = 0x3		CDFS4_BOTH = 0x3
	};		};
	struct BIND_CONN_TO_SESSION4resok {		struct BIND_CONN_TO_SESSION4resok {
	sessionid4 bctsr_sessid;		sessionid4 bctsr_sessid;
	channel_dir_from_server4		channel_dir_from_server4
	skipping to change at line 34984 ¶		skipping to change at line 35082 ¶
	};		};
	union BIND_CONN_TO_SESSION4res		union BIND_CONN_TO_SESSION4res
	switch (nfsstat4 bctsr_status) {		switch (nfsstat4 bctsr_status) {
	case NFS4_OK:		case NFS4_OK:
	BIND_CONN_TO_SESSION4resok		BIND_CONN_TO_SESSION4resok
	bctsr_resok4;		bctsr_resok4;
	default: void;		default: void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_BIND_CONN_TO_SESSION_DESCRIPTION" numb
	</figure>		ered="true">
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_BIND_CONN_TO_SESSION_DESCRIPTION" title="DES		<t>
	CRIPTION">
	<t>
	BIND_CONN_TO_SESSION is used to associate additional connections with a		BIND_CONN_TO_SESSION is used to associate additional connections with a
	session. It MUST be used on the connection being associated with the sessi on. It MUST		session. It <bcp14>MUST</bcp14> be used on the connection being associated with the session. It <bcp14>MUST</bcp14>
	be the only operation in the COMPOUND procedure. If		be the only operation in the COMPOUND procedure. If
	SP4_NONE (<xref target="OP_EXCHANGE_ID" />) state protection		SP4_NONE (<xref target="OP_EXCHANGE_ID" format="default"/>) state protecti on
	is used, any principal,		is used, any principal,
	security flavor, or RPCSEC_GSS context MAY be used to invoke the operation		security flavor, or RPCSEC_GSS context <bcp14>MAY</bcp14> be used to invok
	.		e the operation.
	If SP4_MACH_CRED is used, RPCSEC_GSS MUST be used with the		If SP4_MACH_CRED is used, RPCSEC_GSS <bcp14>MUST</bcp14> be used with the
	integrity or privacy services, using the principal that		integrity or privacy services, using the principal that
	created the client ID. If SP4_SSV is used, RPCSEC_GSS with		created the client ID. If SP4_SSV is used, RPCSEC_GSS with
	the SSV GSS mechanism (<xref target="ssv_mech" />) and integrity or		the SSV GSS mechanism (<xref target="ssv_mech" format="default"/>) and int
	privacy MUST be used.		egrity or
	</t>		privacy <bcp14>MUST</bcp14> be used.
	<t>		</t>
			<t>
	If, when the client ID was created, the client opted for SP4_NONE		If, when the client ID was created, the client opted for SP4_NONE
	state protection,		state protection,
	the client is not required to use BIND_CONN_TO_SESSION to associate the		the client is not required to use BIND_CONN_TO_SESSION to associate the
	connection with the session, unless		connection with the session, unless
	the client wishes to associate the connection with the backchannel.		the client wishes to associate the connection with the backchannel.
	When SP4_NONE protection is used, simply sending a COMPOUND		When SP4_NONE protection is used, simply sending a COMPOUND
	request with a SEQUENCE operation is sufficient to associate the		request with a SEQUENCE operation is sufficient to associate the
	connection with the session specified in SEQUENCE.		connection with the session specified in SEQUENCE.
	</t>		</t>
	<t>		<t>
	The field bctsa_dir indicates whether the client		The field bctsa_dir indicates whether the client
	wants to associate the connection with the fore		wants to associate the connection with the fore
	channel or the backchannel or both channels. The value		channel or the backchannel or both channels. The value
	CDFC4_FORE_OR_BOTH indicates that the client wants to		CDFC4_FORE_OR_BOTH indicates that the client wants to
	associate the connection with both the fore channel and backchannel,		associate the connection with both the fore channel and backchannel,
	but will accept the connection being associated to		but will accept the connection being associated to
	just the fore channel. The value CDFC4_BACK_OR_BOTH		just the fore channel. The value CDFC4_BACK_OR_BOTH
	indicates that the client wants to associate with both		indicates that the client wants to associate with both
	the fore channel and backchannel, but will accept the		the fore channel and backchannel, but will accept the
	connection being associated with just the backchannel.		connection being associated with just the backchannel.
	The server replies in bctsr_dir which channel(s)		The server replies in bctsr_dir which channel(s)
	the connection is associated with.		the connection is associated with.
	If the client specified CDFC4_FORE, the server		If the client specified CDFC4_FORE, the server
	MUST return CDFS4_FORE. If the client specified		<bcp14>MUST</bcp14> return CDFS4_FORE. If the client specified
	CDFC4_BACK, the server MUST return CDFS4_BACK. If the		CDFC4_BACK, the server <bcp14>MUST</bcp14> return CDFS4_BACK. If the
	client specified CDFC4_FORE_OR_BOTH, the server MUST return		client specified CDFC4_FORE_OR_BOTH, the server <bcp14>MUST</bcp14> return
	CDFS4_FORE or CDFS4_BOTH. If the client specified		CDFS4_FORE or CDFS4_BOTH. If the client specified
	CDFC4_BACK_OR_BOTH, the server MUST return CDFS4_BACK		CDFC4_BACK_OR_BOTH, the server <bcp14>MUST</bcp14> return CDFS4_BACK
	or CDFS4_BOTH.		or CDFS4_BOTH.
	</t>		</t>
	<t>		<t>
	See the CREATE_SESSION operation (<xref target="OP_CREATE_SESSION" />),		See the CREATE_SESSION operation (<xref target="OP_CREATE_SESSION" format="
			default"/>),
	and the description of the argument		and the description of the argument
	csa_use_conn_in_rdma_mode to understand		csa_use_conn_in_rdma_mode to understand
	bctsa_use_conn_in_rdma_mode, and the description of		bctsa_use_conn_in_rdma_mode, and the description of
	csr_use_conn_in_rdma_mode to understand bctsr_use_conn_in_rdma_mode.		csr_use_conn_in_rdma_mode to understand bctsr_use_conn_in_rdma_mode.
	</t>		</t>
	<t>		<t>
	Invoking BIND_CONN_TO_SESSION on a connection already associated		Invoking BIND_CONN_TO_SESSION on a connection already associated
	with the specified session has no effect, and the server MUST		with the specified session has no effect, and the server <bcp14>MUST</bcp14 >
	respond with NFS4_OK, unless the client is demanding changes		respond with NFS4_OK, unless the client is demanding changes
	to the set of channels the connection is associated with. If		to the set of channels the connection is associated with. If
	so, the server MUST return NFS4ERR_INVAL.		so, the server <bcp14>MUST</bcp14> return NFS4ERR_INVAL.
	</t>
	</section>		</t>
	<section toc="exclude" anchor="OP_BIND_CONN_TO_SESSION_IMPLEMENTATION" title="		</section>
	IMPLEMENTATION">		<section toc="exclude" anchor="OP_BIND_CONN_TO_SESSION_IMPLEMENTATION" n
	<t>		umbered="true">
			<name>IMPLEMENTATION</name>
			<t>
	If a session's channel loses all connections, depending on		If a session's channel loses all connections, depending on
	the client ID's state protection and type of channel,		the client ID's state protection and type of channel,
	the client might need to use		the client might need to use
	BIND_CONN_TO_SESSION to associate a new connection. If the		BIND_CONN_TO_SESSION to associate a new connection. If the
	server restarted and does not keep the reply cache in stable		server restarted and does not keep the reply cache in stable
	storage, the server will not recognize the session ID.		storage, the server will not recognize the session ID.
	The client will ultimately have to invoke EXCHANGE_ID to		The client will ultimately have to invoke EXCHANGE_ID to
	create a new client ID and session.		create a new client ID and session.
	</t>		</t>
	<t>		<t>
	Suppose SP4_SSV state protection is being used,		Suppose SP4_SSV state protection is being used,
	and BIND_CONN_TO_SESSION is among the operations		and BIND_CONN_TO_SESSION is among the operations
	included in the spo_must_enforce set when the		included in the spo_must_enforce set when the
	client ID was created (<xref target="OP_EXCHANGE_ID"/>).		client ID was created (<xref target="OP_EXCHANGE_ID" format="default"/>).
	If so, there is an issue if SET_SSV is sent, no response		If so, there is an issue if SET_SSV is sent, no response
	is returned, and the last connection associated		is returned, and the last connection associated
	with the client ID drops. The client, per		with the client ID drops. The client, per
	the sessions model, MUST retry the SET_SSV. But		the sessions model, <bcp14>MUST</bcp14> retry the SET_SSV. But
	it needs a new connection to do so, and MUST		it needs a new connection to do so, and <bcp14>MUST</bcp14>
	associate that connection with the session via a		associate that connection with the session via a
	BIND_CONN_TO_SESSION authenticated with the SSV		BIND_CONN_TO_SESSION authenticated with the SSV
	GSS mechanism. The problem is that the RPCSEC_GSS		GSS mechanism. The problem is that the RPCSEC_GSS
	message integrity codes use a subkey derived from the SSV as the		message integrity codes use a subkey derived from the SSV as the
	key and the		key and the
	SSV may have changed. While there are multiple		SSV may have changed. While there are multiple
	recovery strategies, a single, general strategy		recovery strategies, a single, general strategy
	is described here.		is described here.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	The client reconnects.		The client reconnects.
	</t>		</li>
	<t>		<li>
	The client assumes that the SET_SSV was executed,		The client assumes that the SET_SSV was executed,
	and so sends BIND_CONN_TO_SESSION with the subkey (derived from		and so sends BIND_CONN_TO_SESSION with the subkey (derived from
	the new SSV, i.e., what SET_SSV would have set the SSV to)		the new SSV, i.e., what SET_SSV would have set the SSV to)
	used as the key for the RPCSEC_GSS credential message integrity codes.		used as the key for the RPCSEC_GSS credential message integrity codes.
	</t>		</li>
	<t>		<li>
	If the request succeeds, this means that the original attempted SET_SSV		If the request succeeds, this means that the original attempted SET_SSV
	did execute successfully. The client re-sends the original		did execute successfully. The client re-sends the original
	SET_SSV, which the server will reply to via the		SET_SSV, which the server will reply to via the
	reply cache.		reply cache.
	</t>		</li>
	<t>		<li>
	If the server returns an RPC authentication error,		If the server returns an RPC authentication error,
	this means that the server's current SSV was not changed		this means that the server's current SSV was not changed
	(and the SET_SSV was likely not executed). The client then		(and the SET_SSV was likely not executed). The client then
	tries BIND_CONN_TO_SESSION with the subkey derived from the		tries BIND_CONN_TO_SESSION with the subkey derived from the
	old SSV as the		old SSV as the
	key for the RPCSEC_GSS message integrity codes.		key for the RPCSEC_GSS message integrity codes.
	</t>		</li>
	<t>		<li>
	The attempted BIND_CONN_TO_SESSION with the old SSV		The attempted BIND_CONN_TO_SESSION with the old SSV
	should succeed. If so, the client re-sends the original		should succeed. If so, the client re-sends the original
	SET_SSV. If the original SET_SSV was not executed, then the		SET_SSV. If the original SET_SSV was not executed, then the
	server executes it. If the original SET_SSV was executed but		server executes it. If the original SET_SSV was executed but
	failed, the server will return the SET_SSV from the reply		failed, the server will return the SET_SSV from the reply
	cache.		cache.
	</t>		</li>
			</ul>
	</list>		</section>
			</section>
	</t>		<section anchor="OP_EXCHANGE_ID" numbered="true" toc="default">
	</section>		<name>Operation 42: EXCHANGE_ID - Instantiate Client ID</name>
	</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->
	<!-- Copyright (C) The IETF Trust (2007-2008) -->
	<section title="Operation 42: EXCHANGE_ID - Instantiate Client ID"
	anchor="OP_EXCHANGE_ID">
	<t>		<t>
	The EXCHANGE_ID operation exchanges long-hand		The EXCHANGE_ID operation exchanges long-hand client and server identi
	client and server identifiers		fiers
	(owners), and provides access to a client ID, creating one		(owners) and provides access to a client ID, creating one
	if necessary. This client ID becomes associated with the connection		if necessary. This client ID becomes associated with the connection
	on which the operation is done, so that it is available when a		on which the operation is done, so that it is available when a
	CREATE_SESSION is done or when the connection is used to issue		CREATE_SESSION is done or when the connection is used to issue
	a request		a request
	on an existing session associated with the current client.		on an existing session associated with the current client.
	</t>		</t>
	<section title="ARGUMENT"		<section anchor="EXID-arg" toc="exclude" numbered="true">
	anchor="EXID-arg"		<name>ARGUMENT</name>
	toc="exclude">		<sourcecode type="xdr"><![CDATA[
	<t>
	<figure>
	<artwork>
	const EXCHGID4_FLAG_SUPP_MOVED_REFER = 0x00000001;		const EXCHGID4_FLAG_SUPP_MOVED_REFER = 0x00000001;
	const EXCHGID4_FLAG_SUPP_MOVED_MIGR = 0x00000002;		const EXCHGID4_FLAG_SUPP_MOVED_MIGR = 0x00000002;
	const EXCHGID4_FLAG_BIND_PRINC_STATEID = 0x00000100;		const EXCHGID4_FLAG_BIND_PRINC_STATEID = 0x00000100;
	const EXCHGID4_FLAG_USE_NON_PNFS = 0x00010000;		const EXCHGID4_FLAG_USE_NON_PNFS = 0x00010000;
	const EXCHGID4_FLAG_USE_PNFS_MDS = 0x00020000;		const EXCHGID4_FLAG_USE_PNFS_MDS = 0x00020000;
	const EXCHGID4_FLAG_USE_PNFS_DS = 0x00040000;		const EXCHGID4_FLAG_USE_PNFS_DS = 0x00040000;
	const EXCHGID4_FLAG_MASK_PNFS = 0x00070000;		const EXCHGID4_FLAG_MASK_PNFS = 0x00070000;
	skipping to change at line 35161 ¶		skipping to change at line 35248 ¶
	const EXCHGID4_FLAG_UPD_CONFIRMED_REC_A = 0x40000000;		const EXCHGID4_FLAG_UPD_CONFIRMED_REC_A = 0x40000000;
	const EXCHGID4_FLAG_CONFIRMED_R = 0x80000000;		const EXCHGID4_FLAG_CONFIRMED_R = 0x80000000;
	struct state_protect_ops4 {		struct state_protect_ops4 {
	bitmap4 spo_must_enforce;		bitmap4 spo_must_enforce;
	bitmap4 spo_must_allow;		bitmap4 spo_must_allow;
	};		};
	struct ssv_sp_parms4 {		struct ssv_sp_parms4 {
	state_protect_ops4 ssp_ops;		state_protect_ops4 ssp_ops;
	sec_oid4 ssp_hash_algs&lt;>;		sec_oid4 ssp_hash_algs<>;
	sec_oid4 ssp_encr_algs&lt;>;		sec_oid4 ssp_encr_algs<>;
	uint32_t ssp_window;		uint32_t ssp_window;
	uint32_t ssp_num_gss_handles;		uint32_t ssp_num_gss_handles;
	};		};
	enum state_protect_how4 {		enum state_protect_how4 {
	SP4_NONE = 0,		SP4_NONE = 0,
	SP4_MACH_CRED = 1,		SP4_MACH_CRED = 1,
	SP4_SSV = 2		SP4_SSV = 2
	};		};
	skipping to change at line 35186 ¶		skipping to change at line 35273 ¶
	case SP4_MACH_CRED:		case SP4_MACH_CRED:
	state_protect_ops4 spa_mach_ops;		state_protect_ops4 spa_mach_ops;
	case SP4_SSV:		case SP4_SSV:
	ssv_sp_parms4 spa_ssv_parms;		ssv_sp_parms4 spa_ssv_parms;
	};		};
	struct EXCHANGE_ID4args {		struct EXCHANGE_ID4args {
	client_owner4 eia_clientowner;		client_owner4 eia_clientowner;
	uint32_t eia_flags;		uint32_t eia_flags;
	state_protect4_a eia_state_protect;		state_protect4_a eia_state_protect;
	nfs_impl_id4 eia_client_impl_id&lt;1>;		nfs_impl_id4 eia_client_impl_id<1>;
	};		};]]></sourcecode>
	</artwork>
	</figure>
	</t>
	</section>		</section>
	<section title="RESULT"		<section anchor="EXID-res" toc="exclude" numbered="true">
	anchor="EXID-res"		<name>RESULT</name>
	toc="exclude">		<sourcecode type="xdr"><![CDATA[
	<t>
	<figure>
	<artwork>
	struct ssv_prot_info4 {		struct ssv_prot_info4 {
	state_protect_ops4 spi_ops;		state_protect_ops4 spi_ops;
	uint32_t spi_hash_alg;		uint32_t spi_hash_alg;
	uint32_t spi_encr_alg;		uint32_t spi_encr_alg;
	uint32_t spi_ssv_len;		uint32_t spi_ssv_len;
	uint32_t spi_window;		uint32_t spi_window;
	gsshandle4_t spi_handles&lt;>;		gsshandle4_t spi_handles<>;
	};		};
	union state_protect4_r switch(state_protect_how4 spr_how) {		union state_protect4_r switch(state_protect_how4 spr_how) {
	case SP4_NONE:		case SP4_NONE:
	void;		void;
	case SP4_MACH_CRED:		case SP4_MACH_CRED:
	state_protect_ops4 spr_mach_ops;		state_protect_ops4 spr_mach_ops;
	case SP4_SSV:		case SP4_SSV:
	ssv_prot_info4 spr_ssv_info;		ssv_prot_info4 spr_ssv_info;
	};		};
	struct EXCHANGE_ID4resok {		struct EXCHANGE_ID4resok {
	clientid4 eir_clientid;		clientid4 eir_clientid;
	sequenceid4 eir_sequenceid;		sequenceid4 eir_sequenceid;
	uint32_t eir_flags;		uint32_t eir_flags;
	state_protect4_r eir_state_protect;		state_protect4_r eir_state_protect;
	server_owner4 eir_server_owner;		server_owner4 eir_server_owner;
	opaque eir_server_scope&lt;NFS4_OPAQUE_LIMIT>;		opaque eir_server_scope<NFS4_OPAQUE_LIMIT>;
	nfs_impl_id4 eir_server_impl_id&lt;1>;		nfs_impl_id4 eir_server_impl_id<1>;
	};		};
	union EXCHANGE_ID4res switch (nfsstat4 eir_status) {		union EXCHANGE_ID4res switch (nfsstat4 eir_status) {
	case NFS4_OK:		case NFS4_OK:
	EXCHANGE_ID4resok eir_resok4;		EXCHANGE_ID4resok eir_resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
	</artwork>
	</figure>
	</t>
	</section>		</section>
	<section title="DESCRIPTION"		<section anchor="OP_EXCHANGE_ID_DESCRIPTION" toc="exclude" numbered="tru
	anchor="OP_EXCHANGE_ID_DESCRIPTION"		e">
	toc="exclude">		<name>DESCRIPTION</name>
	<t>		<t>
	The client uses the EXCHANGE_ID operation to register		The client uses the EXCHANGE_ID operation to register
	a particular client_owner with the server. However,		a particular instance of that client with the server,
	when the client_owner has already been registered		as represented by a client_owner4. However,
	by other means (e.g. Transparent State Migration), the		when the client_owner4 has already been registered
			by other means (e.g., Transparent State Migration), the
	client may still use EXCHANGE_ID to obtain the client ID		client may still use EXCHANGE_ID to obtain the client ID
	assigned previously.		assigned previously.
	</t>		</t>
	<t>		<t>
	The client ID returned from this		The client ID returned from this
	operation will be associated with the connection		operation will be associated with the connection
	on which the EXCHANGE_ID is received and		on which the EXCHANGE_ID is received and
	will serve as a parent object for		will serve as a parent object for
	sessions created by the client on this connection or		sessions created by the client on this connection or
	to which the connection is bound. As a result of using		to which the connection is bound. As a result of using
	those sessions to make requests involving the creation		those sessions to make requests involving the creation
	of state, that state will become associated with the		of state, that state will become associated with the
	client ID returned.		client ID returned.
	</t>		</t>
	<t>		<t>
	In situations in which the registration of the		In situations in which the registration of the
	client_owner has not occurred previously,		client_owner has not occurred previously,
	the client ID must first be used, along with		the client ID must first be used, along with
	the returned eir_sequenceid, in creating an		the returned eir_sequenceid, in creating an
	associated session using		associated session using
	CREATE_SESSION.		CREATE_SESSION.
	</t>		</t>
	<t>		<t>
	If the flag EXCHGID4_FLAG_CONFIRMED_R is set in the		If the flag EXCHGID4_FLAG_CONFIRMED_R is set in the
	result, eir_flags, then it is an indication that the		result, eir_flags, then it is an indication that the
	registration of the client_owner has already occurred		registration of the client_owner has already occurred
	and that a further CREATE_SESSION is not needed to		and that a further CREATE_SESSION is not needed to
	confirm it. Of course, subsequent CREATE_SESSION		confirm it. Of course, subsequent CREATE_SESSION
	operations may		operations may
	be needed for other reasons.		be needed for other reasons.
	</t>		</t>
	<t>		<t>
	The value eir_sequenceid is used to establish an initial		The value eir_sequenceid is used to establish an initial
	sequence value associate with the client ID returned. In		sequence value associated with the client ID returned. In
	cases in which a CREATE_SESSION has already been done,		cases in which a CREATE_SESSION has already been done,
	there is no need for this value, since sequencing of		there is no need for this value, since sequencing of
	such request has already been established and the client		such request has already been established, and the client
	has no need for this value and will ignore it		has no need for this value and will ignore it.
	</t>		</t>
	<t>		<t>
	EXCHANGE_ID MAY be sent in a COMPOUND procedure that starts with		EXCHANGE_ID <bcp14>MAY</bcp14> be sent in a COMPOUND procedure that starts
			with
	SEQUENCE. However, when a client communicates with a server		SEQUENCE. However, when a client communicates with a server
	for the first time, it will not have a session, so using		for the first time, it will not have a session, so using
	SEQUENCE will not be possible.		SEQUENCE will not be possible.
	If EXCHANGE_ID is sent without a preceding SEQUENCE, then it		If EXCHANGE_ID is sent without a preceding SEQUENCE, then it
	MUST be the only operation in the COMPOUND procedure's request. If		<bcp14>MUST</bcp14> be the only operation in the COMPOUND procedure's reque
	it is not, the server MUST return NFS4ERR_NOT_ONLY_OP.		st. If
	</t>		it is not, the server <bcp14>MUST</bcp14> return NFS4ERR_NOT_ONLY_OP.
			</t>
	<t>		<t>
	The eia_clientowner field is composed of a co_verifier		The eia_clientowner field is composed of a co_verifier
	field and a co_ownerid string. As noted in		field and a co_ownerid string. As noted in
	<xref target="Client_Identifiers"/>, the co_ownerid		<xref target="Client_Identifiers" format="default"/>, the co_ownerid
	identifies the client, and the co_verifier specifies a particular		identifies the client, and the co_verifier specifies a particular
	incarnation of that client. An EXCHANGE_ID		incarnation of that client. An EXCHANGE_ID
	sent with a new incarnation of the client will		sent with a new incarnation of the client will
	lead to the server removing lock state of the old		lead to the server removing lock state of the old
	incarnation. On the other hand, an EXCHANGE_ID sent with the		incarnation. On the other hand, when an EXCHANGE_ID sent with the current
	current incarnation and co_ownerid will, when it does not result		incarnation and co_ownerid does not result in an unrelated error,
	in an unrelated error, potentially update an		it will potentially update an existing client ID's properties or
	existing client ID's properties, or simply		simply return information about the existing client_id. The latter
	return information about the existing client_id. That latter
	would happen when this operation is done to the same server		would happen when this operation is done to the same server
	using different network addresses as part of creating trunked		using different network addresses as part of creating trunked
	connections.		connections.
	</t>		</t>
	<t>		<t>
	A server MUST NOT provide the same client ID to two different		A server <bcp14>MUST NOT</bcp14> provide the same client ID to two differe
			nt
	incarnations of an eia_clientowner.		incarnations of an eia_clientowner.
	</t>		</t>
	<t>		<t>
	In addition to the client ID and sequence ID, the server		In addition to the client ID and sequence ID, the server
	returns a server owner (eir_server_owner) and		returns a server owner (eir_server_owner) and
	server scope (eir_server_scope). The former field is used		server scope (eir_server_scope). The former field is used
	in connection with		in connection with
	network trunking as described in <xref		network trunking as described in <xref target="Trunking" format="default"/>
	target="Trunking" />. The latter field is used to		. The latter field is used to
	allow clients to determine when client IDs sent by		allow clients to determine when client IDs sent by
	one server may be recognized by another in the event		one server may be recognized by another in the event
	of file system migration (see <xref		of file system migration (see <xref target="SEC11-EFF-lock" format="default
	target="SEC11-EFF-lock" /> of the current document).		"/> of the current document).
	</t>		</t>
	<t>		<t>
	The client ID returned by EXCHANGE_ID is only unique		The client ID returned by EXCHANGE_ID is only unique
	relative to the combination of eir_server_owner.so_major_id		relative to the combination of eir_server_owner.so_major_id
	and eir_server_scope. Thus, if two servers return the		and eir_server_scope. Thus, if two servers return the
	same client ID, the onus is on the client to		same client ID, the onus is on the client to
	distinguish the client IDs on the basis of eir_server_owner.so_major_id		distinguish the client IDs on the basis of eir_server_owner.so_major_id
	and eir_server_scope. In the event two different servers		and eir_server_scope. In the event two different servers
	claim matching server_owner.so_major_id and eir_server_scope,		claim matching server_owner.so_major_id and eir_server_scope,
	the client can use the verification techniques discussed		the client can use the verification techniques discussed
	in <xref target="PREP-trunk-verify" /> to determine if the servers		in <xref target="PREP-trunk-verify" format="default"/> to determine if the servers
	are distinct. If they are distinct, then the client		are distinct. If they are distinct, then the client
	will need to note the destination network addresses		will need to note the destination network addresses
	of the connections used with each server and use		of the connections used with each server and use
	the network address as the final discriminator.		the network address as the final discriminator.
	</t>		</t>
	<t>		<t>
	The server, as defined by the unique identity expressed		The server, as defined by the unique identity expressed
	in the so_major_id of the server owner and the server scope,		in the so_major_id of the server owner and the server scope,
	needs to track several properties of each client ID it		needs to track several properties of each client ID it
	hands out. The properties apply to the client ID and all		hands out. The properties apply to the client ID and all
	sessions associated with the client ID.		sessions associated with the client ID.
	The properties are derived from the		The properties are derived from the
	arguments and results of EXCHANGE_ID.		arguments and results of EXCHANGE_ID.
	The client ID properties include:		The client ID properties include:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	The capabilities expressed by the following bits, which		The capabilities expressed by the following bits, which
	come from the results of EXCHANGE_ID:		come from the results of EXCHANGE_ID:
	<list>		</t>
	<t>EXCHGID4_FLAG_SUPP_MOVED_REFER</t>		<ul spacing="normal">
	<t>EXCHGID4_FLAG_SUPP_MOVED_MIGR </t>		<li>EXCHGID4_FLAG_SUPP_MOVED_REFER</li>
	<t>EXCHGID4_FLAG_BIND_PRINC_STATEID </t>		<li>EXCHGID4_FLAG_SUPP_MOVED_MIGR </li>
	<t>EXCHGID4_FLAG_USE_NON_PNFS </t>		<li>EXCHGID4_FLAG_BIND_PRINC_STATEID </li>
	<t>EXCHGID4_FLAG_USE_PNFS_MDS </t>		<li>EXCHGID4_FLAG_USE_NON_PNFS </li>
	<t>EXCHGID4_FLAG_USE_PNFS_DS </t>		<li>EXCHGID4_FLAG_USE_PNFS_MDS </li>
	</list>		<li>EXCHGID4_FLAG_USE_PNFS_DS </li>
			</ul>
			<t>
	These properties may be updated by subsequent		These properties may be updated by subsequent
	EXCHANGE_ID operations on confirmed client IDs though the server MAY		EXCHANGE_ID operations on confirmed client IDs though the server <bcp14> MAY</bcp14>
	refuse to change them.		refuse to change them.
	</t>		</t>
	<t>		</li>
			<li>
	The state protection method used, one of SP4_NONE,		The state protection method used, one of SP4_NONE,
	SP4_MACH_CRED, or SP4_SSV, as set by the spa_how		SP4_MACH_CRED, or SP4_SSV, as set by the spa_how
	field of the arguments to EXCHANGE_ID. Once the		field of the arguments to EXCHANGE_ID. Once the
	client ID is confirmed, this property cannot be		client ID is confirmed, this property cannot be
	updated by subsequent EXCHANGE_ID operations.		updated by subsequent EXCHANGE_ID operations.
	</t>		</li>
	<t>		<li>
			<t>
	For SP4_MACH_CRED or SP4_SSV state protection:		For SP4_MACH_CRED or SP4_SSV state protection:
	<list>		</t>
	<t>		<ul spacing="normal">
	The list of operations (spo_must_enforce) that MUST use the specified		<li>
			The list of operations (spo_must_enforce) that <bcp14>MUST</bcp14> use t
			he specified
	state protection. This list comes		state protection. This list comes
	from the results of EXCHANGE_ID.		from the results of EXCHANGE_ID.
	</t>		</li>
	<t>		<li>
	The list of operations (spo_must_allow) that MAY use the specified		The list of operations (spo_must_allow) that <bcp14>MAY</bcp14> use the
			specified
	state protection. This list comes		state protection. This list comes
	from the results of EXCHANGE_ID.		from the results of EXCHANGE_ID.
	</t>		</li>
	</list>		</ul>
			<t>
	Once the client ID is confirmed, these properties		Once the client ID is confirmed, these properties
	cannot be updated by subsequent EXCHANGE_ID		cannot be updated by subsequent EXCHANGE_ID
	requests.		requests.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	For SP4_SSV protection:		For SP4_SSV protection:
	<list>		</t>
			<ul spacing="normal">
	<t>		<li>
	The OID of the hash algorithm. This property is		The OID of the hash algorithm. This property is
	represented by one of the algorithms in the		represented by one of the algorithms in the
	ssp_hash_algs field of the EXCHANGE_ID arguments.		ssp_hash_algs field of the EXCHANGE_ID arguments.
	Once the client ID is confirmed, this property		Once the client ID is confirmed, this property
	cannot be updated by subsequent EXCHANGE_ID		cannot be updated by subsequent EXCHANGE_ID
	requests.		requests.
	</t>		</li>
	<t>		<li>
	The OID of the encryption algorithm. This property		The OID of the encryption algorithm. This property
	is represented by one of the algorithms in the		is represented by one of the algorithms in the
	ssp_encr_algs field of the EXCHANGE_ID arguments.		ssp_encr_algs field of the EXCHANGE_ID arguments.
	Once the client ID is confirmed, this property		Once the client ID is confirmed, this property
	cannot be updated by subsequent EXCHANGE_ID		cannot be updated by subsequent EXCHANGE_ID
	requests.		requests.
	</t>		</li>
			<li>
	<t>		<t>
	The length of the SSV. This property is		The length of the SSV. This property is
	represented by the spi_ssv_len field in the EXCHANGE_ID		represented by the spi_ssv_len field in the EXCHANGE_ID
	results.		results.
	Once the client ID is confirmed,		Once the client ID is confirmed,
	this property cannot be updated by		this property cannot be updated by
	subsequent EXCHANGE_ID operations.		subsequent EXCHANGE_ID operations.
	<vspace blankLines='1' />		</t>
			<t>
	There are REQUIRED and RECOMMENDED relationships among the		There are <bcp14>REQUIRED</bcp14> and <bcp14>RECOMMENDED</bcp14> relation ships among the
	length of the key of the encryption algorithm ("key length"), the length of the		length of the key of the encryption algorithm ("key length"), the length of the
	output of hash algorithm ("hash length"), and the length of the SSV ("SSV length").		output of hash algorithm ("hash length"), and the length of the SSV ("SSV length").
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	key length MUST be &lt;= hash length. This is because the keys used for		<li>
			key length <bcp14>MUST</bcp14> be &lt;= hash length. This is because the
			keys used for
	the encryption algorithm are actually subkeys derived from the SSV,		the encryption algorithm are actually subkeys derived from the SSV,
	and the derivation is via the hash algorithm. The selection of an		and the derivation is via the hash algorithm. The selection of an
	encryption algorithm with a key length that exceeded the length of		encryption algorithm with a key length that exceeded the length of
	the output of the hash algorithm would require padding, and thus		the output of the hash algorithm would require padding, and thus
	weaken the use of the encryption algorithm.		weaken the use of the encryption algorithm.
	</t>		</li>
	<t>		<li>
	hash length SHOULD be &lt;= SSV length. This is because the		hash length <bcp14>SHOULD</bcp14> be &lt;= SSV length. This is because t
			he
	SSV is a key used to derive subkeys via an HMAC, and		SSV is a key used to derive subkeys via an HMAC, and
	it is recommended that the key used as input to an HMAC be		it is recommended that the key used as input to an HMAC be
	at least as long as the length of the HMAC's hash algorithm's		at least as long as the length of the HMAC's hash algorithm's
	output (see Section 3 of <xref target="RFC2104"/>).		output (see <xref target="RFC2104" sectionFormat="of" section="3"/>).
	</t>		</li>
			<li>
	<t>		key length <bcp14>SHOULD</bcp14> be &lt;= SSV length. This is a transiti
	key length SHOULD be &lt;= SSV length. This is a transitive result of th		ve result of the
	e
	above two invariants.		above two invariants.
	</t>		</li>
			<li>
	<t>		key length <bcp14>SHOULD</bcp14> be &gt;= hash length / 2. This is becau
	key length SHOULD be >= hash length / 2. This is because the subkey		se the subkey
	derivation is via		derivation is via
	an HMAC and it is recommended that if the HMAC has to be truncated,		an HMAC and it is recommended that if the HMAC has to be truncated,
	it should not be truncated to less than half the hash length		it should not be truncated to less than half the hash length
	(see Section 4 of <xref target="RFC2104">RFC2104</xref>).		(see Section <xref target="RFC2104" sectionFormat="bare" section="4"/>
	</t>		of RFC 2104 <xref target="RFC2104" format="default"/>).
	</list>		</li>
	</t>		</ul>
			</li>
	<t>		<li>
	Number of concurrent versions of the SSV the client		Number of concurrent versions of the SSV the client
	and server will support (see <xref target="ssv_mech"/>).		and server will support (see <xref target="ssv_mech" format="default"/>).
	This property is represented by spi_window		This property is represented by spi_window
	in the EXCHANGE_ID results. The property may be		in the EXCHANGE_ID results. The property may be
	updated by subsequent EXCHANGE_ID operations.		updated by subsequent EXCHANGE_ID operations.
	</t>		</li>
	</list>		</ul>
	</t>		</li>
	<t>		<li>
	The client's implementation ID as represented by		The client's implementation ID as represented by
	the eia_client_impl_id field of the arguments.		the eia_client_impl_id field of the arguments.
	The property may be updated by subsequent EXCHANGE_ID		The property may be updated by subsequent EXCHANGE_ID
	requests.		requests.
	</t>		</li>
	<t>		<li>
	The server's implementation ID as represented by		The server's implementation ID as represented by
	the eir_server_impl_id field of the reply.		the eir_server_impl_id field of the reply.
	The property may be updated by replies to subsequent EXCHANGE_ID		The property may be updated by replies to subsequent EXCHANGE_ID
	requests.		requests.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The eia_flags passed as part of the arguments and		The eia_flags passed as part of the arguments and
	the eir_flags results allow the client and server		the eir_flags results allow the client and server
	to inform each other of their capabilities as well		to inform each other of their capabilities as well
	as indicate how the client ID will be used. Whether		as indicate how the client ID will be used. Whether
	a bit is set or cleared on the arguments' flags		a bit is set or cleared on the arguments' flags
	does not force the server to set or clear the same		does not force the server to set or clear the same
	bit on the results' side. Bits not defined above		bit on the results' side. Bits not defined above
	cannot be set in the eia_flags field. If they		cannot be set in the eia_flags field. If they
	are, the server MUST reject the operation with		are, the server <bcp14>MUST</bcp14> reject the operation with
	NFS4ERR_INVAL.		NFS4ERR_INVAL.
	</t>		</t>
	<t>		<t>
	The EXCHGID4_FLAG_UPD_CONFIRMED_REC_A bit can only be set		The EXCHGID4_FLAG_UPD_CONFIRMED_REC_A bit can only be set
	in eia_flags; it is always off in eir_flags.		in eia_flags; it is always off in eir_flags.
	The EXCHGID4_FLAG_CONFIRMED_R bit can only be set in		The EXCHGID4_FLAG_CONFIRMED_R bit can only be set in
	eir_flags; it is always off in eia_flags. If the		eir_flags; it is always off in eia_flags. If the
	server recognizes the co_ownerid and co_verifier		server recognizes the co_ownerid and co_verifier
	as mapping to a confirmed client ID, it sets		as mapping to a confirmed client ID, it sets
	EXCHGID4_FLAG_CONFIRMED_R in eir_flags.		EXCHGID4_FLAG_CONFIRMED_R in eir_flags.
	The EXCHGID4_FLAG_CONFIRMED_R flag allows a client		The EXCHGID4_FLAG_CONFIRMED_R flag allows a client
	to tell if the client ID it is trying to create		to tell if the client ID it is trying to create
	already exists and is confirmed.		already exists and is confirmed.
	</t>		</t>
			<t>
	<t>
	If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is set in eia_flags,		If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is set in eia_flags,
	this means that the client is attempting to update properties		this means that the client is attempting to update properties
	of an existing confirmed client ID (if the client wants to		of an existing confirmed client ID (if the client wants to
	update properties of an unconfirmed client ID, it MUST NOT		update properties of an unconfirmed client ID, it <bcp14>MUST NOT</bcp14>
	set EXCHGID4_FLAG_UPD_CONFIRMED_REC_A).		set EXCHGID4_FLAG_UPD_CONFIRMED_REC_A).
	If so, it is		If so, it is
	RECOMMENDED that the client send the update EXCHANGE_ID		<bcp14>RECOMMENDED</bcp14> that the client send the update EXCHANGE_ID
	operation in the same COMPOUND as a SEQUENCE so that		operation in the same COMPOUND as a SEQUENCE so that
	the EXCHANGE_ID is executed exactly once. Whether		the EXCHANGE_ID is executed exactly once. Whether
	the client can update the properties of client ID		the client can update the properties of client ID
	depends on the state protection it selected when the		depends on the state protection it selected when the
	client ID was created, and the principal and security		client ID was created, and the principal and security
	flavor it used when sending the EXCHANGE_ID operation.		flavor it used when sending the EXCHANGE_ID operation.
	The situations described in items		The situations described in items
	<xref target="case_update" format="counter"/>,		<xref target="case_update" format="counter"/>,
	<xref target="case_update_noent" format="counter"/>,		<xref target="case_update_noent" format="counter"/>,
	<xref target="case_update_exist" format="counter"/>,		<xref target="case_update_exist" format="counter"/>,
	or		or
	<xref target="case_update_perm" format="counter"/>		<xref target="case_update_perm" format="counter"/>
	of the second numbered list of <xref		of the second numbered list of <xref target="OP_EXCHANGE_ID_IMPLEMENTATION
	target="OP_EXCHANGE_ID_IMPLEMENTATION" /> below will apply.		" format="default"/> below will apply.
	Note that if the operation succeeds		Note that if the operation succeeds
	and returns a client ID that is already		and returns a client ID that is already
	confirmed, the server MUST set the		confirmed, the server <bcp14>MUST</bcp14> set the
	EXCHGID4_FLAG_CONFIRMED_R bit in eir_flags.		EXCHGID4_FLAG_CONFIRMED_R bit in eir_flags.
	</t>		</t>
			<t>
	<t>
	If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is not set in eia_flags,		If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is not set in eia_flags,
	this means that the client is trying to establish a new		this means that the client is trying to establish a new
	client ID; it is		client ID; it is
	attempting to trunk data communication to		attempting to trunk data communication to
	the server (See <xref target="Trunking"/>); or it		the server (See <xref target="Trunking" format="default"/>); or it
	is attempting to update properties of an unconfirmed		is attempting to update properties of an unconfirmed
	client ID. The		client ID. The
	situations described in		situations described in
	items		items
	<xref target="case_new_owner_id" format="counter"/>,		<xref target="case_new_owner_id" format="counter"/>,
	<xref target="case_non_update" format="counter"/>,		<xref target="case_non_update" format="counter"/>,
	<xref target="case_client_collision" format="counter"/>,		<xref target="case_client_collision" format="counter"/>,
	<xref target="case_retry" format="counter"/>, or		<xref target="case_retry" format="counter"/>, or
	<xref target="case_client_restart" format="counter"/>		<xref target="case_client_restart" format="counter"/>
	of the second numbered list of <xref		of the second numbered list of <xref target="OP_EXCHANGE_ID_IMPLEMENTATION
	target="OP_EXCHANGE_ID_IMPLEMENTATION" /> below will apply.		" format="default"/> below will apply.
	Note that if the operation succeeds		Note that if the operation succeeds
	and returns a client ID that was previously		and returns a client ID that was previously
	confirmed, the server MUST set the		confirmed, the server <bcp14>MUST</bcp14> set the
	EXCHGID4_FLAG_CONFIRMED_R bit in eir_flags.		EXCHGID4_FLAG_CONFIRMED_R bit in eir_flags.
	</t>		</t>
			<t>
	<t>
	When the EXCHGID4_FLAG_SUPP_MOVED_REFER flag bit		When the EXCHGID4_FLAG_SUPP_MOVED_REFER flag bit
	is set, the client indicates that it is capable		is set, the client indicates that it is capable
	of dealing with an NFS4ERR_MOVED error as part of		of dealing with an NFS4ERR_MOVED error as part of
	a referral sequence. When this bit is not set, it		a referral sequence. When this bit is not set, it
	is still legal for the server to perform a referral		is still legal for the server to perform a referral
	sequence. However, a server may use the fact that		sequence. However, a server may use the fact that
	the client is incapable of correctly responding		the client is incapable of correctly responding
	to a referral, by avoiding it for that particular		to a referral, by avoiding it for that particular
	client. It may, for instance, act as a proxy		client. It may, for instance, act as a proxy
	for that particular file system, at some cost in		for that particular file system, at some cost in
	performance, although it is not obligated to do so.		performance, although it is not obligated to do so.
	If the server will potentially perform a referral, it		If the server will potentially perform a referral, it
	MUST set EXCHGID4_FLAG_SUPP_MOVED_REFER in eir_flags.		<bcp14>MUST</bcp14> set EXCHGID4_FLAG_SUPP_MOVED_REFER in eir_flags.
	</t>		</t>
	<t>		<t>
	When the EXCHGID4_FLAG_SUPP_MOVED_MIGR is set,		When the EXCHGID4_FLAG_SUPP_MOVED_MIGR is set,
	the client indicates that it is capable of dealing		the client indicates that it is capable of dealing
	with an NFS4ERR_MOVED error as part of a file system		with an NFS4ERR_MOVED error as part of a file system
	migration sequence. When this bit is not set, it		migration sequence. When this bit is not set, it
	is still legal for the server to indicate that a		is still legal for the server to indicate that a
	file system has moved, when this in fact happens.		file system has moved, when this in fact happens.
	However, a server may use the fact that the client		However, a server may use the fact that the client
	is incapable of correctly responding to a migration		is incapable of correctly responding to a migration
	in its scheduling of file systems to migrate so as to		in its scheduling of file systems to migrate so as to
	avoid migration of file systems being actively used.		avoid migration of file systems being actively used.
	It may also hide actual migrations from clients		It may also hide actual migrations from clients
	unable to deal with them by acting as a proxy for a		unable to deal with them by acting as a proxy for a
	migrated file system for particular clients, at some		migrated file system for particular clients, at some
	cost in performance, although it is not obligated		cost in performance, although it is not obligated
	to do so. If the server will potentially perform a		to do so. If the server will potentially perform a
	migration, it MUST set EXCHGID4_FLAG_SUPP_MOVED_MIGR		migration, it <bcp14>MUST</bcp14> set EXCHGID4_FLAG_SUPP_MOVED_MIGR
	in eir_flags.		in eir_flags.
	</t>		</t>
	<t>		<t>
	When EXCHGID4_FLAG_BIND_PRINC_STATEID is set, the		When EXCHGID4_FLAG_BIND_PRINC_STATEID is set, the
	client indicates that it wants the server to bind the		client indicates that it wants the server to bind the
	stateid to the principal. This means that when a		stateid to the principal. This means that when a
	principal creates a stateid, it has to be the one to		principal creates a stateid, it has to be the one to
	use the stateid. If the server will perform binding,		use the stateid. If the server will perform binding,
	it will return EXCHGID4_FLAG_BIND_PRINC_STATEID. The		it will return EXCHGID4_FLAG_BIND_PRINC_STATEID. The
	server MAY return EXCHGID4_FLAG_BIND_PRINC_STATEID		server <bcp14>MAY</bcp14> return EXCHGID4_FLAG_BIND_PRINC_STATEID
	even if the client does not request it. If		even if the client does not request it. If
	an update to the client ID changes the value		an update to the client ID changes the value
	of EXCHGID4_FLAG_BIND_PRINC_STATEID's client		of EXCHGID4_FLAG_BIND_PRINC_STATEID's client
	ID property, the effect applies only to new		ID property, the effect applies only to new
	stateids. Existing stateids (and all stateids with		stateids. Existing stateids (and all stateids with
	the same "other" field) that were created with		the same "other" field) that were created with
	stateid to principal binding in force will continue		stateid to principal binding in force will continue
	to have binding in force. Existing stateids (and all		to have binding in force. Existing stateids (and all
	stateids with the same "other" field) that were created		stateids with the same "other" field) that were created
	with stateid to principal not in force will continue		with stateid to principal not in force will continue
	to have binding not in force.		to have binding not in force.
	</t>		</t>
			<t>
	<t>
	The EXCHGID4_FLAG_USE_NON_PNFS,		The EXCHGID4_FLAG_USE_NON_PNFS,
	EXCHGID4_FLAG_USE_PNFS_MDS, and		EXCHGID4_FLAG_USE_PNFS_MDS, and
	EXCHGID4_FLAG_USE_PNFS_DS bits are described in		EXCHGID4_FLAG_USE_PNFS_DS bits are described in
	<xref target="Client_ID_and_Session_Association"/> and convey roles the		<xref target="pnfs_session_stuff"/>
			and convey roles the
	client ID is to be used for in a pNFS environment.		client ID is to be used for in a pNFS environment.
	The server MUST set one of the acceptable combinations		The server <bcp14>MUST</bcp14> set one of the acceptable combinations
	of these bits (roles) in eir_flags, as specified in that		of these bits (roles) in eir_flags, as specified in that
	section.		section.
	Note that the same client owner/server owner pair can		Note that the same client owner/server owner pair can
	have multiple roles. Multiple roles can be associated		have multiple roles. Multiple roles can be associated
	with the same client ID or with different client		with the same client ID or with different client
	IDs. Thus, if a client sends EXCHANGE_ID from the		IDs. Thus, if a client sends EXCHANGE_ID from the
	same client owner to the same server owner multiple		same client owner to the same server owner multiple
	times, but specifies different pNFS roles each time,		times, but specifies different pNFS roles each time,
	the server might return different client IDs. Given		the server might return different client IDs. Given
	that different pNFS roles might have different client		that different pNFS roles might have different client
	IDs, the client may ask for different properties for		IDs, the client may ask for different properties for
	each role/client ID.		each role/client ID.
	</t>		</t>
			<t>
	<t>
	The spa_how field of the eia_state_protect field		The spa_how field of the eia_state_protect field
	specifies how the client wants to protect its client,		specifies how the client wants to protect its client,
	locking, and session states from unauthorized changes		locking, and session states from unauthorized changes
	(<xref target="protect_state_change"/>):		(<xref target="protect_state_change" format="default"/>):
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	SP4_NONE. The client does not request the NFSv4.1 server		SP4_NONE. The client does not request the NFSv4.1 server
	to enforce state protection. The NFSv4.1 server MUST NOT		to enforce state protection. The NFSv4.1 server <bcp14>MUST NOT</bcp14>
	enforce state protection for the returned client ID.		enforce state protection for the returned client ID.
	</t>		</li>
	<t>		<li>
			<t>
	SP4_MACH_CRED. If spa_how is SP4_MACH_CRED, then		SP4_MACH_CRED. If spa_how is SP4_MACH_CRED, then
	the client MUST send the EXCHANGE_ID operation with RPCSEC_GSS		the client <bcp14>MUST</bcp14> send the EXCHANGE_ID operation with RPCSEC_ GSS
	as the security flavor, and with a service of		as the security flavor, and with a service of
	RPC_GSS_SVC_INTEGRITY or RPC_GSS_SVC_PRIVACY. If SP4_MACH_CRED		RPC_GSS_SVC_INTEGRITY or RPC_GSS_SVC_PRIVACY. If SP4_MACH_CRED
	is specified, then the		is specified, then the
	client wants to use an RPCSEC_GSS-based machine		client wants to use an RPCSEC_GSS-based machine
	credential to protect its state. The server MUST note		credential to protect its state. The server <bcp14>MUST</bcp14> note
	the principal the EXCHANGE_ID operation was sent		the principal the EXCHANGE_ID operation was sent
	with, and the GSS mechanism used. These notes		with, and the GSS mechanism used. These notes
	collectively comprise the machine credential.		collectively comprise the machine credential.
	<vspace blankLines='1' />		</t>
			<t>
	After the client ID is confirmed, as long as the lease associated with		After the client ID is confirmed, as long as the lease associated with
	the client ID is unexpired, a subsequent EXCHANGE_ID		the client ID is unexpired, a subsequent EXCHANGE_ID
	operation that uses the same eia_clientowner.co_owner		operation that uses the same eia_clientowner.co_owner
	as the first EXCHANGE_ID MUST also use the same		as the first EXCHANGE_ID <bcp14>MUST</bcp14> also use the same
	machine credential as the first EXCHANGE_ID. The		machine credential as the first EXCHANGE_ID. The
	server returns the same client ID for		server returns the same client ID for
	the subsequent EXCHANGE_ID as that returned from		the subsequent EXCHANGE_ID as that returned from
	the first EXCHANGE_ID.		the first EXCHANGE_ID.
	</t>		</t>
	<t>		</li>
			<li>
	SP4_SSV. If spa_how is SP4_SSV, then		SP4_SSV. If spa_how is SP4_SSV, then
	the client MUST send the EXCHANGE_ID operation with RPCSEC_GSS		the client <bcp14>MUST</bcp14> send the EXCHANGE_ID operation with RPCSEC_ GSS
	as the security flavor, and with a service of		as the security flavor, and with a service of
	RPC_GSS_SVC_INTEGRITY or RPC_GSS_SVC_PRIVACY.		RPC_GSS_SVC_INTEGRITY or RPC_GSS_SVC_PRIVACY.
	If SP4_SSV is specified, then		If SP4_SSV is specified, then
	the client wants to use the SSV to protect its state.		the client wants to use the SSV to protect its state.
	The server records the credential used in the request		The server records the credential used in the request
	as the machine credential (as defined above) for		as the machine credential (as defined above) for
	the eia_clientowner.co_owner.		the eia_clientowner.co_owner.
	The CREATE_SESSION operation that		The CREATE_SESSION operation that
	confirms the client ID MUST use the same machine		confirms the client ID <bcp14>MUST</bcp14> use the same machine
	credential.		credential.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	When a client specifies SP4_MACH_CRED or SP4_SSV,		When a client specifies SP4_MACH_CRED or SP4_SSV,
	it also provides two lists of operations (each		it also provides two lists of operations (each
	expressed as a bitmap). The first list		expressed as a bitmap). The first list
	is spo_must_enforce and consists of those operations		is spo_must_enforce and consists of those operations
	the client MUST send (subject to the server confirming the		the client <bcp14>MUST</bcp14> send (subject to the server confirming the
	list of operations in the result of EXCHANGE_ID) with the		list of operations in the result of EXCHANGE_ID) with the
	machine credential (if SP4_MACH_CRED protection is		machine credential (if SP4_MACH_CRED protection is
	specified) or the SSV-based credential (if SP4_SSV		specified) or the SSV-based credential (if SP4_SSV
	protection is used). The client MUST send the		protection is used). The client <bcp14>MUST</bcp14> send the
	operations with RPCSEC_GSS credentials that specify		operations with RPCSEC_GSS credentials that specify
	the RPC_GSS_SVC_INTEGRITY or RPC_GSS_SVC_PRIVACY		the RPC_GSS_SVC_INTEGRITY or RPC_GSS_SVC_PRIVACY
	security service. Typically, the first list of		security service. Typically, the first list of
	operations includes EXCHANGE_ID, CREATE_SESSION,		operations includes EXCHANGE_ID, CREATE_SESSION,
	DELEGPURGE, DESTROY_SESSION, BIND_CONN_TO_SESSION,		DELEGPURGE, DESTROY_SESSION, BIND_CONN_TO_SESSION,
	and DESTROY_CLIENTID. The client SHOULD NOT specify		and DESTROY_CLIENTID. The client <bcp14>SHOULD NOT</bcp14> specify
	in this list any operations that require a filehandle		in this list any operations that require a filehandle
	because the server's access policies MAY conflict with		because the server's access policies <bcp14>MAY</bcp14> conflict with
	the client's choice, and thus the client would then be		the client's choice, and thus the client would then be
	unable to access a subset of the server's namespace.		unable to access a subset of the server's namespace.
	</t>		</t>
	<t>		<t>
	Note that if SP4_SSV protection is specified, and		Note that if SP4_SSV protection is specified, and
	the client indicates that CREATE_SESSION must be		the client indicates that CREATE_SESSION must be
	protected with SP4_SSV, because the SSV cannot exist		protected with SP4_SSV, because the SSV cannot exist
	without a confirmed client ID, the first CREATE_SESSION		without a confirmed client ID, the first CREATE_SESSION
	MUST instead be sent using the machine credential,		<bcp14>MUST</bcp14> instead be sent using the machine credential,
	and the server MUST accept the machine credential.		and the server <bcp14>MUST</bcp14> accept the machine credential.
	</t>		</t>
	<t>		<t>
	There is a corresponding result, also called spo_must_enforce,		There is a corresponding result, also called spo_must_enforce,
	of the operations for which the server will require SP4_MACH_CRED or		of the operations for which the server will require SP4_MACH_CRED or
	SP4_SSV protection. Normally, the server's result		SP4_SSV protection. Normally, the server's result
	equals the client's argument, but the result MAY be different.		equals the client's argument, but the result <bcp14>MAY</bcp14> be differen t.
	If the client requests one or more operations in		If the client requests one or more operations in
	the set { EXCHANGE_ID, CREATE_SESSION,		the set { EXCHANGE_ID, CREATE_SESSION,
	DELEGPURGE, DESTROY_SESSION, BIND_CONN_TO_SESSION,		DELEGPURGE, DESTROY_SESSION, BIND_CONN_TO_SESSION,
	DESTROY_CLIENTID }, then the result spo_must_enforce		DESTROY_CLIENTID }, then the result spo_must_enforce
	MUST include the operations the client requested from that set.		<bcp14>MUST</bcp14> include the operations the client requested from that s et.
	</t>		</t>
	<t>		<t>
	If spo_must_enforce in the results has BIND_CONN_TO_SESSION		If spo_must_enforce in the results has BIND_CONN_TO_SESSION
	set, then connection binding enforcement is enabled, and		set, then connection binding enforcement is enabled, and
	the client MUST use the machine (if SP4_MACH_CRED protection is used)		the client <bcp14>MUST</bcp14> use the machine (if SP4_MACH_CRED protection is used)
	or SSV (if SP4_SSV protection is used) credential on calls		or SSV (if SP4_SSV protection is used) credential on calls
	to BIND_CONN_TO_SESSION.		to BIND_CONN_TO_SESSION.
	</t>		</t>
	<t>		<t>
	The second list is spo_must_allow and consists of those		The second list is spo_must_allow and consists of those
	operations		operations
	the client wants to have the option of sending with the machine credential or		the client wants to have the option of sending with the machine credential or
	the SSV-based credential, even if the object the		the SSV-based credential, even if the object the
	operations are performed on is not owned by the		operations are performed on is not owned by the
	machine or SSV credential.		machine or SSV credential.
	</t>		</t>
	<t>		<t>
	The corresponding result, also called		The corresponding result, also called
	spo_must_allow, consists of the operations the server		spo_must_allow, consists of the operations the server
	will allow the client to use SP4_SSV or SP4_MACH_CRED		will allow the client to use SP4_SSV or SP4_MACH_CRED
	credentials with.		credentials with.
	Normally, the server's result		Normally, the server's result
	equals the client's argument, but the result MAY be different.		equals the client's argument, but the result <bcp14>MAY</bcp14> be differen t.
	</t>		</t>
	<t>		<t>
	The purpose of spo_must_allow is to allow clients to		The purpose of spo_must_allow is to allow clients to
	solve the following conundrum. Suppose the client ID		solve the following conundrum. Suppose the client ID
	is confirmed with EXCHGID4_FLAG_BIND_PRINC_STATEID,		is confirmed with EXCHGID4_FLAG_BIND_PRINC_STATEID,
	and it calls OPEN with the RPCSEC_GSS credentials of		and it calls OPEN with the RPCSEC_GSS credentials of
	a normal user. Now suppose the user's credentials expire,		a normal user. Now suppose the user's credentials expire,
	and cannot be renewed (e.g., a Kerberos ticket granting ticket		and cannot be renewed (e.g., a Kerberos ticket granting ticket
	expires, and the user has logged off and will not be		expires, and the user has logged off and will not be
	acquiring a new ticket granting ticket). The client will be		acquiring a new ticket granting ticket). The client will be
	unable to send CLOSE without the user's credentials, which is to		unable to send CLOSE without the user's credentials, which is to
	say the client has to either leave the state on the server		say the client has to either leave the state on the server
	or re-send EXCHANGE_ID with a new verifier to		or re-send EXCHANGE_ID with a new verifier to
	clear all state, that is, unless the client includes		clear all state, that is, unless the client includes
	CLOSE on the list of operations in spo_must_allow and the		CLOSE on the list of operations in spo_must_allow and the
	server agrees.		server agrees.
	</t>		</t>
	<t>		<t>
	The SP4_SSV protection parameters also have:		The SP4_SSV protection parameters also have:
	<list style="hanging">		</t>
			<dl newline="true" spacing="normal">
	<t hangText="ssp_hash_algs:" />		<dt>ssp_hash_algs:</dt>
	<t>		<dd><t>
	This is the set of algorithms the client supports		This is the set of algorithms the client supports
	for the purpose of computing the digests needed for		for the purpose of computing the digests needed for
	the internal SSV GSS mechanism and for the SET_SSV		the internal SSV GSS mechanism and for the SET_SSV
	operation. Each algorithm is specified as an object		operation. Each algorithm is specified as an object
	identifier (OID). The REQUIRED algorithms for a		identifier (OID). The <bcp14>REQUIRED</bcp14> algorithms for a
	server are id-sha1, id-sha224, id-sha256, id-sha384,		server are id-sha1, id-sha224, id-sha256, id-sha384,
	and id-sha512 <xref target="RFC4055"/>.		and id-sha512 <xref target="RFC4055" format="default"/>.</t>
	</t>		<t>
	<t>		Due to known weaknesses in id-sha1, it is <bcp14>RECOMMENDED</bcp14>
	Due to known weaknesses in id-sha1, it is RECOMMENDED
	that the client specify at least one		that the client specify at least one
	algorithm within ssp_hash_algs other than id-sha1.		algorithm within ssp_hash_algs other than id-sha1.</t>
	</t>		<t>
	<t>
	The algorithm the server selects among the		The algorithm the server selects among the
	set is indicated in spi_hash_alg, a field of		set is indicated in spi_hash_alg, a field of
	spr_ssv_prot_info. The field spi_hash_alg is an		spr_ssv_prot_info. The field spi_hash_alg is an
	index into the array ssp_hash_algs. Because of		index into the array ssp_hash_algs. Because of
	known the weaknesses in id-sha1, it is RECOMMENDED that		known the weaknesses in id-sha1, it is <bcp14>RECOMMENDED</bcp14> that
	it not be selected by the server as long as ssp_hash_algs		it not be selected by the server as long as ssp_hash_algs
	contains any other supported algorithm.		contains any other supported algorithm.</t>
	</t>		<t>
	<t>
	If the server		If the server
	does not support any of the offered algorithms,		does not support any of the offered algorithms,
	it returns NFS4ERR_HASH_ALG_UNSUPP.		it returns NFS4ERR_HASH_ALG_UNSUPP.
			If ssp_hash_algs is empty, the server <bcp14>MUST</bcp14> return
	If ssp_hash_algs is empty, the server MUST return NFS4ERR_INVAL.		NFS4ERR_INVAL. </t>
			</dd>
	</t>		<dt>ssp_encr_algs:</dt>
	<t hangText="ssp_encr_algs:" />		<dd>
	<t>
	This is the set of algorithms the client supports for the		This is the set of algorithms the client supports for the
	purpose of providing privacy protection for the internal		purpose of providing privacy protection for the internal
	SSV GSS mechanism. Each algorithm is		SSV GSS mechanism. Each algorithm is
	specified as an OID.		specified as an OID.
	The REQUIRED algorithm for a server is id-aes256-CBC.		The <bcp14>REQUIRED</bcp14> algorithm for a server is id-aes256-CBC.
	The RECOMMENDED algorithms are id-aes192-CBC and id-aes128-CBC		The <bcp14>RECOMMENDED</bcp14> algorithms are id-aes192-CBC and id-aes128
	<xref target="CSOR_AES" />. The selected algorithm is		-CBC
			<xref target="CSOR_AES" format="default"/>. The selected algorithm is
	returned in spi_encr_alg, an index into ssp_encr_algs.		returned in spi_encr_alg, an index into ssp_encr_algs.
	If the server		If the server
	does not support any of the offered algorithms,		does not support any of the offered algorithms,
	it returns NFS4ERR_ENCR_ALG_UNSUPP.		it returns NFS4ERR_ENCR_ALG_UNSUPP.
	If ssp_encr_algs is empty, the server MUST return NFS4ERR_INVAL.		If ssp_encr_algs is empty, the server <bcp14>MUST</bcp14> return NFS4ERR_ INVAL.
	Note that due to previously stated requirements and recommendations		Note that due to previously stated requirements and recommendations
	on the relationships between key length and hash length, some		on the relationships between key length and hash length, some
	combinations of RECOMMENDED and REQUIRED encryption algorithm and		combinations of <bcp14>RECOMMENDED</bcp14> and <bcp14>REQUIRED</bcp14> en
	hash algorithm either SHOULD NOT or MUST NOT be used.		cryption algorithm and
	<xref target="algtbl"/> summarizes the illegal and discouraged		hash algorithm either <bcp14>SHOULD NOT</bcp14> or <bcp14>MUST NOT</bcp14
			> be used.
			<xref target="algtbl" format="default"/> summarizes the illegal and disco
			uraged
	combinations.		combinations.
			</dd>
	</t>		<dt>ssp_window:</dt>
	<t hangText="ssp_window:" />		<dd>
	<t>
	This is the number of SSV versions the client wants		This is the number of SSV versions the client wants
	the server to maintain (i.e., each successful call to SET_SSV		the server to maintain (i.e., each successful call to SET_SSV
	produces a new version of the SSV). If ssp_window is zero, the		produces a new version of the SSV). If ssp_window is zero, the
	server MUST return NFS4ERR_INVAL. The server responds		server <bcp14>MUST</bcp14> return NFS4ERR_INVAL. The server responds
	with spi_window, which MUST NOT exceed ssp_window and MUST		with spi_window, which <bcp14>MUST NOT</bcp14> exceed ssp_window and <bcp
			14>MUST</bcp14>
	be at least one.		be at least one.
	Any requests on the backchannel or fore channel that		Any requests on the backchannel or fore channel that
	are using a version of the SSV that is outside the window will fail with		are using a version of the SSV that is outside the window will fail with
	an ONC RPC authentication error, and the requester		an ONC RPC authentication error, and the requester
	will have to retry them with the same slot ID and		will have to retry them with the same slot ID and
	sequence ID.		sequence ID.
	</t>		</dd>
			<dt>ssp_num_gss_handles:</dt>
	<t hangText="ssp_num_gss_handles:" />		<dd>
	<t>		<t>
	This is the number of RPCSEC_GSS handles the		This is the number of RPCSEC_GSS handles the
	server should create that are based on the GSS		server should create that are based on the GSS
	SSV mechanism (see		SSV mechanism (see
	<xref target="ssv_mech" />).		<xref target="ssv_mech" format="default"/>).
	It is not the total number of RPCSEC_GSS handles for		It is not the total number of RPCSEC_GSS handles for
	the client ID. Indeed, subsequent calls to EXCHANGE_ID		the client ID. Indeed, subsequent calls to EXCHANGE_ID
	will add RPCSEC_GSS handles.		will add RPCSEC_GSS handles.
	The server responds with a list of handles in		The server responds with a list of handles in
	spi_handles. If the client asks for at least		spi_handles. If the client asks for at least
	one handle and the server cannot create it,		one handle and the server cannot create it,
	the server MUST return an error. The handles in		the server <bcp14>MUST</bcp14> return an error. The handles in
	spi_handles are not available for use until the		spi_handles are not available for use until the
	client ID is confirmed, which could be immediately		client ID is confirmed, which could be immediately
	if EXCHANGE_ID returns EXCHGID4_FLAG_CONFIRMED_R,		if EXCHANGE_ID returns EXCHGID4_FLAG_CONFIRMED_R,
	or upon successful confirmation from CREATE_SESSION.		or upon successful confirmation from CREATE_SESSION.
	<vspace blankLines='1' />		</t>
			<t>
	While a client ID can span all the connections		While a client ID can span all the connections
	that are connected to a server sharing the same		that are connected to a server sharing the same
	eir_server_owner.so_major_id, the RPCSEC_GSS		eir_server_owner.so_major_id, the RPCSEC_GSS
	handles returned in spi_handles can only be used		handles returned in spi_handles can only be used
	on connections connected to a server that returns		on connections connected to a server that returns
	the same the eir_server_owner.so_major_id and		the same the eir_server_owner.so_major_id and
	eir_server_owner.so_minor_id on each connection.		eir_server_owner.so_minor_id on each connection.
	It is permissible for the client to set		It is permissible for the client to set
	ssp_num_gss_handles to zero; the client can		ssp_num_gss_handles to zero; the client can
	create more handles with another EXCHANGE_ID call.		create more handles with another EXCHANGE_ID call.
	<vspace blankLines='1' />		</t>
			<t>
	Because each SSV RPCSEC_GSS handle shares a common SSV GSS context,		Because each SSV RPCSEC_GSS handle shares a common SSV GSS context,
	there are security considerations specific to this situation		there are security considerations specific to this situation
	discussed in <xref target="rpcsec_ssv_consider"/>.		discussed in <xref target="rpcsec_ssv_consider" format="default"/>.
	<vspace blankLines='1' />		</t>
	The seq_window (see Section 5.2.3.1 of RFC2203 <xref target="RFC2203"/>)		<t>
			The seq_window (see Section <xref target="RFC2203" sectionFormat="bare" s
			ection="5.2.3.1"/> of RFC 2203
			<xref target="RFC2203" format="default"/>)
	of each RPCSEC_GSS handle in spi_handle		of each RPCSEC_GSS handle in spi_handle
	MUST be the same as the seq_window of		<bcp14>MUST</bcp14> be the same as the seq_window of
	the RPCSEC_GSS handle used for the credential of the RPC request		the RPCSEC_GSS handle used for the credential of the RPC request
	that the EXCHANGE_ID operation was sent as a part of.		of which the EXCHANGE_ID operation was sent as a part.
			</t>
	</t>		</dd>
			</dl>
	</list>		<table anchor="algtbl" align="center">
			<thead>
	</t>		<tr>
	<texttable anchor='algtbl'>		<th align="left">Encryption Algorithm</th>
	<ttcol align='left'>Encryption Algorithm</ttcol>		<th align="left"><bcp14>MUST NOT</bcp14> be combined with</th>
	<ttcol align='left'>MUST NOT be combined with</ttcol>		<th align="left"><bcp14>SHOULD NOT</bcp14> be combined with</th>
	<ttcol align='left'>SHOULD NOT be combined with</ttcol>		</tr>
	<c>id-aes128-CBC</c> <c></c> <c>id-sha384, id-sha512</c>		</thead>
	<c>id-aes192-CBC</c> <c>id-sha1</c> <c>id-sha512</c>		<tbody>
	<c>id-aes256-CBC</c> <c>id-sha1, id-sha224</c> <c></c>		<tr>
	</texttable>		<td align="left">id-aes128-CBC</td>
			<td align="left"/>
	<t>		<td align="left">id-sha384, id-sha512</td>
			</tr>
			<tr>
			<td align="left">id-aes192-CBC</td>
			<td align="left">id-sha1</td>
			<td align="left">id-sha512</td>
			</tr>
			<tr>
			<td align="left">id-aes256-CBC</td>
			<td align="left">id-sha1, id-sha224</td>
			<td align="left"/>
			</tr>
			</tbody>
			</table>
			<t>
	The arguments include an array of up to one		The arguments include an array of up to one
	element in length called eia_client_impl_id. If		element in length called eia_client_impl_id. If
	eia_client_impl_id is present, it contains the		eia_client_impl_id is present, it contains the
	information identifying the implementation of the		information identifying the implementation of the
	client. Similarly, the results include an array of up		client. Similarly, the results include an array of up
	to one element in length called eir_server_impl_id		to one element in length called eir_server_impl_id
	that identifies the implementation of the server.		that identifies the implementation of the server.
	Servers MUST accept a zero-length eia_client_impl_id		Servers <bcp14>MUST</bcp14> accept a zero-length eia_client_impl_id
	array, and clients MUST accept a zero-length		array, and clients <bcp14>MUST</bcp14> accept a zero-length
	eir_server_impl_id array.		eir_server_impl_id array.
	</t>		</t>
	<t>		<t>
	A possible use for implementation identifiers		A possible use for implementation identifiers
	would be in diagnostic software that extracts		would be in diagnostic software that extracts
	this information in an attempt to identify		this information in an attempt to identify
	interoperability problems, performance workload		interoperability problems, performance workload
	behaviors, or general usage statistics. Since the		behaviors, or general usage statistics. Since the
	intent of having access to this information is for		intent of having access to this information is for
	planning or general diagnosis only, the client and		planning or general diagnosis only, the client and
	server MUST NOT interpret this implementation		server <bcp14>MUST NOT</bcp14> interpret this implementation
	identity information in a way that affects		identity information in a way that affects
	how the implementation interacts with		how the implementation interacts with
	its peer. The client and server are not		its peer. The client and server are not
	allowed to depend on the peer's manifesting a particular		allowed to depend on the peer's manifesting a particular
	allowed behavior based on an implementation identifier		allowed behavior based on an implementation identifier
	but are required to interoperate as specified elsewhere		but are required to interoperate as specified elsewhere
	in the protocol specification.		in the protocol specification.
	</t>		</t>
	<t>		<t>
	Because it is possible that some implementations might		Because it is possible that some implementations might
	violate the protocol specification and interpret		violate the protocol specification and interpret
	the identity information, implementations MUST		the identity information, implementations <bcp14>MUST</bcp14>
	provide facilities to allow the NFSv4 client and server		provide facilities to allow the NFSv4 client and server
	be configured to		to be configured to set the contents of the nfs_impl_id structures sent
	set the contents of the nfs_impl_id structures sent
	to any specified value.		to any specified value.
	</t>		</t>
			</section>
	</section>		<section anchor="OP_EXCHANGE_ID_IMPLEMENTATION" toc="exclude" numbered="
	<section title="IMPLEMENTATION"		true">
	anchor="OP_EXCHANGE_ID_IMPLEMENTATION"		<name>IMPLEMENTATION</name>
	toc="exclude">		<t>
	<t>
	A server's client record is a 5-tuple:		A server's client record is a 5-tuple:
	</t>		</t>
	<t>		<ol spacing="normal" type="1">
	<list style="numbers">		<li>
	<t>co_ownerid		<t>co_ownerid:
	<list style="empty">		</t>
	<t>The client identifier string, from the eia_clientowner		<t>
			The client identifier string, from the eia_clientowner
	structure of the EXCHANGE_ID4args structure.</t>		structure of the EXCHANGE_ID4args structure.</t>
	</list></t>		</li>
			<li>
	<t>co_verifier:		<t>co_verifier:
	<list style="empty">		</t>
	<t>A client-specific value used to indicate incarnations (where a clien		<t>A client-specific value used to indicate incarnations (where
	t restart represents a new incarnation), from the		a client restart represents a new incarnation), from the
	eia_clientowner structure of the EXCHANGE_ID4args		eia_clientowner structure of the EXCHANGE_ID4args
	structure.</t>		structure.</t>
	</list></t>		</li>
			<li>
	<t>principal:		<t>principal:
	<list style="empty">		</t>
	<t>		<t>
	The principal that was defined in the RPC header's credential		The principal that was defined in the RPC header's credential
	and/or verifier at the time the client record was		and/or verifier at the time the client record was
	established.		established.
	</t>		</t>
	</list></t>		</li>
			<li>
	<t>client ID:		<t>client ID:
	<list style="empty">		</t>
	<t>The shorthand client identifier, generated by the server and		<t>The shorthand client identifier, generated by the server and
	returned via the eir_clientid field in the EXCHANGE_ID4resok		returned via the eir_clientid field in the EXCHANGE_ID4resok
	structure.</t>		structure.</t>
	</list></t>		</li>
			<li>
	<t>confirmed:		<t>confirmed:
	<list style="empty">		</t>
	<t>A private field on the server indicating whether or not a		<t>A private field on the server indicating whether or not a
	client record has been confirmed. A client record is		client record has been confirmed. A client record is
	confirmed if there has been a successful CREATE_SESSION		confirmed if there has been a successful CREATE_SESSION
	operation to confirm it. Otherwise, it is unconfirmed. An		operation to confirm it. Otherwise, it is unconfirmed. An
	unconfirmed record is established by an EXCHANGE_ID call.		unconfirmed record is established by an EXCHANGE_ID call.
	Any unconfirmed record that is not confirmed within a lease		Any unconfirmed record that is not confirmed within a lease
	period SHOULD be removed.</t>		period <bcp14>SHOULD</bcp14> be removed.</t>
	</list></t>		</li>
			</ol>
	</list>
	</t>
	<!-- start new list -->
	<t>		<t>
	The following identifiers represent special values for the fields		The following identifiers represent special values for the fields
	in the records.		in the records.
	<list style="hanging">		</t>
	<t hangText="ownerid_arg:"/>		<dl newline="true" spacing="normal">
	<t>		<dt>ownerid_arg:</dt>
			<dd>
	The value of the eia_clientowner.co_ownerid subfield of the		The value of the eia_clientowner.co_ownerid subfield of the
	EXCHANGE_ID4args structure of the current request.		EXCHANGE_ID4args structure of the current request.
	</t>		</dd>
	<t hangText="verifier_arg:"/>		<dt>verifier_arg:</dt>
	<t>		<dd>
	The value of the eia_clientowner.co_verifier subfield of the		The value of the eia_clientowner.co_verifier subfield of the
	EXCHANGE_ID4args structure of the current request.		EXCHANGE_ID4args structure of the current request.
	</t>		</dd>
	<t hangText="old_verifier_arg:"/>		<dt>old_verifier_arg:</dt>
	<t>		<dd>
	A value of the eia_clientowner.co_verifier field of a client record		A value of the eia_clientowner.co_verifier field of a client record
	received in a previous request; this is distinct from		received in a previous request; this is distinct from
	verifier_arg.		verifier_arg.
	</t>		</dd>
	<t hangText="principal_arg:"/>		<dt>principal_arg:</dt>
	<t>		<dd>
	The value of the RPCSEC_GSS principal for the current request.		The value of the RPCSEC_GSS principal for the current request.
	</t>		</dd>
	<t hangText="old_principal_arg:"/>		<dt>old_principal_arg:</dt>
	<t>		<dd>
	A value of the principal of a client record as defined by the		A value of the principal of a client record as defined by the
	RPC header's credential or verifier of a previous request.		RPC header's credential or verifier of a previous request.
	This is distinct from principal_arg.		This is distinct from principal_arg.
			</dd>
	</t>		<dt>clientid_ret:</dt>
	<t hangText="clientid_ret:"/>		<dd>
	<t>
	The value of the eir_clientid field the server will return in the		The value of the eir_clientid field the server will return in the
	EXCHANGE_ID4resok structure for the current request.		EXCHANGE_ID4resok structure for the current request.
	</t>		</dd>
	<t hangText="old_clientid_ret:"/>		<dt>old_clientid_ret:</dt>
	<t>		<dd>
	The value of the eir_clientid field the server returned in the		The value of the eir_clientid field the server returned in the
	EXCHANGE_ID4resok structure for a previous request. This		EXCHANGE_ID4resok structure for a previous request. This
	is distinct from clientid_ret.		is distinct from clientid_ret.
	</t>		</dd>
	<t hangText="confirmed:"/>		<dt>confirmed:</dt>
	<t>		<dd>
	The client ID has been confirmed.		The client ID has been confirmed.
	</t>		</dd>
	<t hangText="unconfirmed:"/>		<dt>unconfirmed:</dt>
	<t>		<dd>
	The client ID has not been confirmed.		The client ID has not been confirmed.
	</t>		</dd>
	</list>		</dl>
	</t>		<t>
	<t>
	Since EXCHANGE_ID is a non-idempotent operation, we must		Since EXCHANGE_ID is a non-idempotent operation, we must
	consider the possibility that retries occur as a result of a		consider the possibility that retries occur as a result of a
	client restart, network partition, malfunctioning router, etc.		client restart, network partition, malfunctioning router, etc.
	Retries are identified by the value of the eia_clientowner field of		Retries are identified by the value of the eia_clientowner field of
	EXCHANGE_ID4args, and the method for dealing with them is		EXCHANGE_ID4args, and the method for dealing with them is
	outlined in the scenarios below.		outlined in the scenarios below.
	</t>		</t>
	<t>		<t>
	The scenarios are described in terms of the		The scenarios are described in terms of the
	client record(s) a server has for a given		client record(s) a server has for a given
	co_ownerid. Note that if the client ID		co_ownerid. Note that if the client ID
	was created specifying SP4_SSV state protection and		was created specifying SP4_SSV state protection and
	EXCHANGE_ID as the one of the operations in spo_must_allow,		EXCHANGE_ID as the one of the operations in spo_must_allow,
	then the server MUST authorize EXCHANGE_IDs with the SSV		then the server <bcp14>MUST</bcp14> authorize EXCHANGE_IDs with the SSV
	principal in addition to the principal that created the		principal in addition to the principal that created the
	client ID.		client ID.
	</t>		</t>
	<t anchor="case_list">
	<list style="numbers">		<ol spacing="normal" type="1">
	<t anchor="case_new_owner_id">New Owner ID		<li anchor="case_new_owner_id">
	<list style="empty">		<t>New Owner ID
	<t>		</t>
			<t>
	If the server has no client records		If the server has no client records
	with eia_clientowner.co_ownerid matching		with eia_clientowner.co_ownerid matching
	ownerid_arg, and EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is not		ownerid_arg, and EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is not
	set in the EXCHANGE_ID, then a new shorthand		set in the EXCHANGE_ID, then a new shorthand
	client ID (let us call it clientid_ret)		client ID (let us call it clientid_ret)
	is generated, and the following unconfirmed		is generated, and the following unconfirmed
	record is added to the server's state.		record is added to the server's state.
			</t>
	<vspace blankLines='1' />		<t>
	{ ownerid_arg, verifier_arg, principal_arg, clientid_ret, unconfirmed }		{ ownerid_arg, verifier_arg, principal_arg, clientid_ret, unconfirmed }
			</t>
	<vspace blankLines='1' />		<t>
	Subsequently, the server returns clientid_ret.		Subsequently, the server returns clientid_ret.
			</t>
			</li>
	<vspace blankLines='1' />		<li anchor="case_non_update">
			<t>Non-Update on Existing Client ID</t>
	</t>		<t>
	</list>
	<vspace blankLines='1' />
	</t>
	<t anchor="case_non_update">Non-Update on Existing Client ID
	<list style="empty">
	<t>
	If the server has the following confirmed record, and		If the server has the following confirmed record, and
	the request does not have		the request does not have
	EXCHGID4_FLAG_UPD_CONFIRMED_REC_A set,		EXCHGID4_FLAG_UPD_CONFIRMED_REC_A set,
	then the request is the result of a retried request due to a		then the request is the result of a retried request due to a
	faulty router or lost connection, or		faulty router or lost connection, or
	the client is trying to determine if it can perform		the client is trying to determine if it can perform
	trunking.		trunking.
			</t>
	<vspace blankLines='1' />		<t>
	{ ownerid_arg, verifier_arg, principal_arg, clientid_ret, confirmed }		{ ownerid_arg, verifier_arg, principal_arg, clientid_ret, confirmed }
			</t>
	<vspace blankLines='1' />		<t>
	Since the record has been confirmed, the client		Since the record has been confirmed, the client
	must have received the server's reply from		must have received the server's reply from
	the initial EXCHANGE_ID request. Since the		the initial EXCHANGE_ID request. Since the
	server has a confirmed record, and since		server has a confirmed record, and since
	EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is not set, with the		EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is not set, with the
	possible exception of eir_server_owner.so_minor_id, the		possible exception of eir_server_owner.so_minor_id, the
	server returns the same result it did when		server returns the same result it did when
	the client ID's properties were last updated		the client ID's properties were last updated
	(or if never updated, the result when the		(or if never updated, the result when the
	client ID was created). The confirmed record		client ID was created). The confirmed record
	is unchanged.		is unchanged.
	</t>		</t>
	</list>		</li>
	</t>
	<t anchor="case_client_collision">Client Collision		<li anchor="case_client_collision">
	<list style="empty">		<t>Client Collision
	<t>		</t>
			<t>
	If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is not set, and		If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is not set, and
	if the server has the following confirmed		if the server has the following confirmed
	record, then this request is likely the result		record, then this request is likely the result
	of a chance collision between the values of		of a chance collision between the values of
	the eia_clientowner.co_ownerid subfield of		the eia_clientowner.co_ownerid subfield of
	EXCHANGE_ID4args for two different clients.		EXCHANGE_ID4args for two different clients.
	</t>		</t>
	<t>		<t>
	{ ownerid_arg, *, old_principal_arg, old_clientid_ret, confirmed }		{ ownerid_arg, *, old_principal_arg, old_clientid_ret, confirmed }
	</t>		</t>
	<t>		<t>
	If there is currently no state associated with old_clientid_ret,		If there is currently no state associated with old_clientid_ret,
	or if there is state but the lease has expired, then		or if there is state but the lease has expired, then
	this case is effectively equivalent to the		this case is effectively equivalent to the
	New Owner ID case of <xref target="case_new_owner_id"/>.		New Owner ID case of <xref target="case_new_owner_id" format="defaul t"/>.
	The confirmed record is deleted, the old_clientid_ret and its		The confirmed record is deleted, the old_clientid_ret and its
	lock state are deleted,		lock state are deleted,
	a new shorthand client ID		a new shorthand client ID
	is generated, and the following unconfirmed		is generated, and the following unconfirmed
	record is added to the server's state.		record is added to the server's state.
			</t>
	<vspace blankLines='1' />		<t>
	{ ownerid_arg, verifier_arg, principal_arg, clientid_ret, unconfirmed }		{ ownerid_arg, verifier_arg, principal_arg, clientid_ret, unconfirmed }
			</t>
	<vspace blankLines='1' />		<t>
	Subsequently, the server returns clientid_ret.		Subsequently, the server returns clientid_ret.
			</t>
	<vspace blankLines='1' />		<t>
	</t>
	<t>
	If old_clientid_ret has an unexpired lease with state, then		If old_clientid_ret has an unexpired lease with state, then
	no state of old_clientid_ret is changed or deleted.		no state of old_clientid_ret is changed or deleted.
	The server returns NFS4ERR_CLID_INUSE		The server returns NFS4ERR_CLID_INUSE
	to indicate that the client should		to indicate that the client should
	retry with a different value for the		retry with a different value for the
	eia_clientowner.co_ownerid subfield of		eia_clientowner.co_ownerid subfield of
	EXCHANGE_ID4args. The client record is not changed.		EXCHANGE_ID4args. The client record is not changed.</t>
	</t>		</li>
	</list>
	</t>
	<t anchor="case_retry">Replacement of Unconfirmed Record		<li anchor="case_retry">
	<list style="empty">		<t>Replacement of Unconfirmed Record
	<t>		</t>
			<t>
	If the EXCHGID4_FLAG_UPD_CONFIRMED_REC_A flag is not set,		If the EXCHGID4_FLAG_UPD_CONFIRMED_REC_A flag is not set,
	and the server has the following unconfirmed record, then		and the server has the following unconfirmed record, then
	the client is attempting EXCHANGE_ID again on an		the client is attempting EXCHANGE_ID again on an
	unconfirmed client ID, perhaps due to a retry, a client		unconfirmed client ID, perhaps due to a retry, a client
	restart before client ID confirmation (i.e.,		restart before client ID confirmation (i.e.,
	before CREATE_SESSION was called), or		before CREATE_SESSION was called), or
	some other reason.		some other reason.
			</t>
	<vspace blankLines='1' />		<t>
	{ ownerid_arg, *, *, old_clientid_ret, unconfirmed }		{ ownerid_arg, *, *, old_clientid_ret, unconfirmed }
			</t>
	<vspace blankLines='1' />		<t>
	It is possible that		It is possible that
	the properties of old_clientid_ret are		the properties of old_clientid_ret are
	different than those specified in the current		different than those specified in the current
	EXCHANGE_ID. Whether or not the properties are being updated,		EXCHANGE_ID. Whether or not the properties are being updated,
	to eliminate ambiguity, the server		to eliminate ambiguity, the server
	deletes the unconfirmed record, generates a		deletes the unconfirmed record, generates a
	new client ID (clientid_ret), and establishes		new client ID (clientid_ret), and establishes
	the following unconfirmed record:		the following unconfirmed record:
			</t>
	<vspace blankLines='1' />		<t>
	{ ownerid_arg, verifier_arg, principal_arg, clientid_ret, unconfirmed }		{ ownerid_arg, verifier_arg, principal_arg, clientid_ret, unconfirmed }
	<vspace blankLines='1' />		</t>
	</t>		</li>
	</list>
	</t>
	<t anchor="case_client_restart">Client Restart		<li anchor="case_client_restart">
	<list style="empty">		<t>Client Restart</t>
	<t>		<t>
	If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is not set, and		If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is not set, and
	if the server has the following confirmed client record, then		if the server has the following confirmed client record, then
	this request is likely from a previously confirmed client		this request is likely from a previously confirmed client
	that has restarted.		that has restarted.
	</t>		</t>
	<t>		<t>
	{ ownerid_arg, old_verifier_arg, principal_arg, old_clientid_ret, con firmed }		{ ownerid_arg, old_verifier_arg, principal_arg, old_clientid_ret, con firmed }
	</t>		</t>
	<t>		<t>
	Since the previous incarnation of the same		Since the previous incarnation of the same
	client will no longer be making requests,		client will no longer be making requests,
	once the new client ID is confirmed by		once the new client ID is confirmed by
	CREATE_SESSION, byte-range locks and share reservations		CREATE_SESSION, byte-range locks and share reservations
	should be released immediately rather than		should be released immediately rather than
	forcing the new incarnation to wait for		forcing the new incarnation to wait for
	the lease time on the previous incarnation		the lease time on the previous incarnation
	to expire. Furthermore, session state should		to expire. Furthermore, session state should
	be removed since if the client had maintained		be removed since if the client had maintained
	that information across restart, this request		that information across restart, this request
	would not have been sent. If the server		would not have been sent. If the server
	supports neither the CLAIM_DELEGATE_PREV		supports neither the CLAIM_DELEGATE_PREV
	nor CLAIM_DELEG_PREV_FH		nor CLAIM_DELEG_PREV_FH
	claim types, associated delegations should be		claim types, associated delegations should be
	purged as well; otherwise, delegations are		purged as well; otherwise, delegations are
	retained and recovery proceeds according to		retained and recovery proceeds according to
	<xref target="delegation_recovery"/>.		<xref target="delegation_recovery" format="default"/>.
	</t>		</t>
	<t>		<t>
	After processing, clientid_ret is returned to the client and		After processing, clientid_ret is returned to the client and
	this client record is added:		this client record is added:
	</t>		</t>
	<t>		<t>
	{ ownerid_arg, verifier_arg, principal_arg, clientid_ret, unconfirmed }		{ ownerid_arg, verifier_arg, principal_arg, clientid_ret, unconfirmed }
	<vspace blankLines='1' />		</t>
	</t>		<t>
	<t>
	The previously described confirmed record		The previously described confirmed record
	continues to exist, and thus the same		continues to exist, and thus the same
	ownerid_arg exists in both a confirmed and		ownerid_arg exists in both a confirmed and
	unconfirmed state at the same time. The number		unconfirmed state at the same time. The number
	of states can collapse to one once the server		of states can collapse to one once the server
	receives an applicable CREATE_SESSION or		receives an applicable CREATE_SESSION or
	EXCHANGE_ID.		EXCHANGE_ID.
			</t>
	<list style='symbols'>		<ul spacing="normal">
			<li>
	<t>
	If the server subsequently receives a successful		If the server subsequently receives a successful
	CREATE_SESSION that confirms clientid_ret,		CREATE_SESSION that confirms clientid_ret,
	then the server atomically destroys the		then the server atomically destroys the
	confirmed record and makes the unconfirmed		confirmed record and makes the unconfirmed
	record confirmed as described in		record confirmed as described in
	<xref target="OP_CREATE_SESSION_DESCRIPTION" />.		<xref target="OP_CREATE_SESSION_DESCRIPTION" format="default"/>.
			</li>
	</t>		<li>
	<t>
	If the server instead subsequently receives		If the server instead subsequently receives
	an EXCHANGE_ID with the client owner equal		an EXCHANGE_ID with the client owner equal
	to ownerid_arg, one strategy is to simply		to ownerid_arg, one strategy is to simply
	delete the unconfirmed record, and process the		delete the unconfirmed record, and process the
	EXCHANGE_ID as described in the entirety of		EXCHANGE_ID as described in the entirety of
	<xref target="OP_EXCHANGE_ID_IMPLEMENTATION"		<xref target="OP_EXCHANGE_ID_IMPLEMENTATION" format="default"/>.
	/>.		</li>
			</ul>
	</t>		</li>
	</list>
	</t>
	</list>
	</t>
	<t anchor="case_update">Update		<li anchor="case_update">
	<list style="empty">		<t>Update
	<t>		</t>
			<t>
	If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is set, and the		If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is set, and the
	server has the following confirmed record,		server has the following confirmed record,
	then this request is an attempt at an update.		then this request is an attempt at an update.
			</t>
	<vspace blankLines='1' />		<t>
	{ ownerid_arg, verifier_arg, principal_arg, clientid_ret, confirmed }		{ ownerid_arg, verifier_arg, principal_arg, clientid_ret, confirmed }
			</t>
	<vspace blankLines='1' />		<t>
	Since the record has been confirmed, the client must have		Since the record has been confirmed, the client must have
	received the server's reply from the initial EXCHANGE_ID		received the server's reply from the initial EXCHANGE_ID
	request. The server allows the update, and the client record		request. The server allows the update, and the client record
	is left intact.		is left intact.
	</t>		</t>
	</list>		</li>
	</t>
	<t anchor="case_update_noent">Update but No Confirmed Record		<li anchor="case_update_noent">
	<list style="empty">		<t>Update but No Confirmed Record
	<t>		</t>
			<t>
	If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is set, and the		If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is set, and the
	server has no confirmed record corresponding ownerid_arg,		server has no confirmed record corresponding ownerid_arg,
	then the server returns NFS4ERR_NOENT and leaves any unconfirmed		then the server returns NFS4ERR_NOENT and leaves any unconfirmed
	record intact.		record intact.
	</t>		</t>
	</list>		</li>
	</t>
	<t anchor="case_update_exist">Update but Wrong Verifier		<li anchor="case_update_exist">
	<list style="empty">		<t>Update but Wrong Verifier
	<t>		</t>
			<t>
	If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is set, and the		If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is set, and the
	server has the following confirmed record,		server has the following confirmed record,
	then this request is an illegal attempt at an		then this request is an illegal attempt at an
	update, perhaps because of a retry from a previous client		update, perhaps because of a retry from a previous client
	incarnation.		incarnation.
			</t>
	<vspace blankLines='1' />		<t>
	{ ownerid_arg, old_verifier_arg, *, clientid_ret, confirmed }		{ ownerid_arg, old_verifier_arg, *, clientid_ret, confirmed }
			</t>
	<vspace blankLines='1' />		<t>
	The server returns NFS4ERR_NOT_SAME and leaves the client record		The server returns NFS4ERR_NOT_SAME and leaves the client record
	intact.		intact.
	</t>		</t>
	</list>		</li>
	</t>
	<t anchor="case_update_perm">Update but Wrong Principal		<li anchor="case_update_perm">
	<list style="empty">		<t>Update but Wrong Principal
	<t>		</t>
			<t>
	If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is set, and the		If EXCHGID4_FLAG_UPD_CONFIRMED_REC_A is set, and the
	server has the following confirmed record,		server has the following confirmed record,
	then this request is an illegal attempt at an		then this request is an illegal attempt at an
	update by an unauthorized principal.		update by an unauthorized principal.
			</t>
	<vspace blankLines='1' />		<t>
	{ ownerid_arg, verifier_arg, old_principal_arg, clientid_ret, confirmed }		{ ownerid_arg, verifier_arg, old_principal_arg, clientid_ret, confirmed }
			</t>
	<vspace blankLines='1' />		<t>
	The server returns NFS4ERR_PERM and leaves the client record		The server returns NFS4ERR_PERM and leaves the client record
	intact.		intact.
	</t>		</t>
	</list>		</li>
	</t>		</ol>
	</list>
	</t>
	</section>		</section>
			</section>
	</section>		<section anchor="OP_CREATE_SESSION" numbered="true" toc="default">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>Operation 43: CREATE_SESSION - Create New Session and Confirm Clie
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		nt ID</name>
	$ -->		<section toc="exclude" anchor="OP_CREATE_SESSION_ARGUMENT" numbered="tru
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		e">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_CREATE_SESSION" title="Operation 43: CREATE_SESSION - Create		<sourcecode type="xdr"><![CDATA[
	New Session and Confirm Client ID" >
	<section toc="exclude" anchor="OP_CREATE_SESSION_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct channel_attrs4 {		struct channel_attrs4 {
	count4 ca_headerpadsize;		count4 ca_headerpadsize;
	count4 ca_maxrequestsize;		count4 ca_maxrequestsize;
	count4 ca_maxresponsesize;		count4 ca_maxresponsesize;
	count4 ca_maxresponsesize_cached;		count4 ca_maxresponsesize_cached;
	count4 ca_maxoperations;		count4 ca_maxoperations;
	count4 ca_maxrequests;		count4 ca_maxrequests;
	uint32_t ca_rdma_ird&lt;1>;		uint32_t ca_rdma_ird<1>;
	};		};
	const CREATE_SESSION4_FLAG_PERSIST = 0x00000001;		const CREATE_SESSION4_FLAG_PERSIST = 0x00000001;
	const CREATE_SESSION4_FLAG_CONN_BACK_CHAN = 0x00000002;		const CREATE_SESSION4_FLAG_CONN_BACK_CHAN = 0x00000002;
	const CREATE_SESSION4_FLAG_CONN_RDMA = 0x00000004;		const CREATE_SESSION4_FLAG_CONN_RDMA = 0x00000004;
	struct CREATE_SESSION4args {		struct CREATE_SESSION4args {
	clientid4 csa_clientid;		clientid4 csa_clientid;
	sequenceid4 csa_sequence;		sequenceid4 csa_sequence;
	uint32_t csa_flags;		uint32_t csa_flags;
	channel_attrs4 csa_fore_chan_attrs;		channel_attrs4 csa_fore_chan_attrs;
	channel_attrs4 csa_back_chan_attrs;		channel_attrs4 csa_back_chan_attrs;
	uint32_t csa_cb_program;		uint32_t csa_cb_program;
	callback_sec_parms4 csa_sec_parms&lt;>;		callback_sec_parms4 csa_sec_parms<>;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_CREATE_SESSION_RESULT" numbered="true"
	</figure>		>
	</section>		<name>RESULT</name>
	<section toc="exclude" anchor="OP_CREATE_SESSION_RESULT" title="RESULT">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct CREATE_SESSION4resok {		struct CREATE_SESSION4resok {
	sessionid4 csr_sessionid;		sessionid4 csr_sessionid;
	sequenceid4 csr_sequence;		sequenceid4 csr_sequence;
	uint32_t csr_flags;		uint32_t csr_flags;
	channel_attrs4 csr_fore_chan_attrs;		channel_attrs4 csr_fore_chan_attrs;
	channel_attrs4 csr_back_chan_attrs;		channel_attrs4 csr_back_chan_attrs;
	};		};
	union CREATE_SESSION4res switch (nfsstat4 csr_status) {		union CREATE_SESSION4res switch (nfsstat4 csr_status) {
	case NFS4_OK:		case NFS4_OK:
	CREATE_SESSION4resok csr_resok4;		CREATE_SESSION4resok csr_resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_CREATE_SESSION_DESCRIPTION" numbered="
	</figure>		true">
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_CREATE_SESSION_DESCRIPTION" title="DESCRIPTI		<t>
	ON">
	<t>
	This operation is used by the client to create new session objects		This operation is used by the client to create new session objects
	on the server.		on the server.
	</t>		</t>
	<t>		<t>
	CREATE_SESSION can be sent with or without a preceding SEQUENCE		CREATE_SESSION can be sent with or without a preceding SEQUENCE
	operation in the same COMPOUND procedure.		operation in the same COMPOUND procedure.
	If CREATE_SESSION is sent with a preceding SEQUENCE		If CREATE_SESSION is sent with a preceding SEQUENCE
	operation,		operation,
	any session created by CREATE_SESSION has no direct		any session created by CREATE_SESSION has no direct
	relation to the session specified in the SEQUENCE operation, although		relation to the session specified in the SEQUENCE operation, although
	the two sessions might be associated with the same client ID.		the two sessions might be associated with the same client ID.
	If CREATE_SESSION is sent without a preceding SEQUENCE, then it		If CREATE_SESSION is sent without a preceding SEQUENCE, then it
	MUST be the only operation in the COMPOUND procedure's request. If		<bcp14>MUST</bcp14> be the only operation in the COMPOUND procedure's requ
	it is not, the server MUST return NFS4ERR_NOT_ONLY_OP.		est. If
	</t>		it is not, the server <bcp14>MUST</bcp14> return NFS4ERR_NOT_ONLY_OP.
	<t>		</t>
			<t>
	In addition to creating a session, CREATE_SESSION has the following		In addition to creating a session, CREATE_SESSION has the following
	effects:		effects:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The first session created with a new		The first session created with a new
	client ID serves to confirm the		client ID serves to confirm the
	creation of that		creation of that
	client's state on the server. The server returns the parameter		client's state on the server. The server returns the parameter
	values for the new session.		values for the new session.
	</t>		</li>
	<t>		<li>
	The connection CREATE_SESSION that is sent over is associated with the		The connection CREATE_SESSION that is sent over is associated with the
	session's fore channel.		session's fore channel.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The arguments and results of CREATE_SESSION are described as follows:		The arguments and results of CREATE_SESSION are described as follows:
	<list style="hanging">		</t>
	<t hangText="csa_clientid:"/>		<dl newline="false" spacing="normal">
	<t>		<dt>csa_clientid:</dt>
			<dd>
	This is the client ID with which the new session will be associated.		This is the client ID with which the new session will be associated.
	The corresponding result is csr_sessionid, the session ID		The corresponding result is csr_sessionid, the session ID
	of the new session.		of the new session.
	</t>		</dd>
	<t hangText="csa_sequence:"/>		<dt>csa_sequence:</dt>
	<t>		<dd>
	Each client ID serializes CREATE_SESSION via a per-client ID		Each client ID serializes CREATE_SESSION via a per-client ID
	sequence number (see		sequence number (see
	<xref target="OP_CREATE_SESSION_IMPLEMENTATION" />).		<xref target="OP_CREATE_SESSION_IMPLEMENTATION" format="default"/>).
	The corresponding result is csr_sequence, which MUST be equal to		The corresponding result is csr_sequence, which <bcp14>MUST</bcp14> be
			equal to
	csa_sequence.		csa_sequence.
	</t>		</dd>
	</list>		</dl>
	</t>		<t>
	<t>
	In the next three arguments, the client offers a value		In the next three arguments, the client offers a value
	that is to be a property of the session. Except where		that is to be a property of the session. Except where
	stated otherwise, it is RECOMMENDED that		stated otherwise, it is <bcp14>RECOMMENDED</bcp14> that
	the server accept the value.		the server accept the value.
	If it is not acceptable, the server MAY use a different value.		If it is not acceptable, the server <bcp14>MAY</bcp14> use a different va
	Regardless, the server MUST return the value the session will		lue.
			Regardless, the server <bcp14>MUST</bcp14> return the value the session w
			ill
	use (which will be either what the client offered, or what		use (which will be either what the client offered, or what
	the server is insisting on) to the client.		the server is insisting on) to the client.
	<list style="hanging">		</t>
	<t hangText="csa_flags:"/>		<dl newline="false" spacing="normal">
	<t>		<dt>csa_flags:</dt>
			<dd>
			<t>
	The csa_flags field contains a list of the following flag		The csa_flags field contains a list of the following flag
	bits:		bits:
	<list style="hanging">		</t>
	<t hangText="CREATE_SESSION4_FLAG_PERSIST:"/>
	<t>		<dl newline="true" spacing="normal">
			<dt>CREATE_SESSION4_FLAG_PERSIST:</dt>
			<dd>
			<t>
	If CREATE_SESSION4_FLAG_PERSIST is set, the client		If CREATE_SESSION4_FLAG_PERSIST is set, the client
	wants the server to provide a persistent reply cache.		wants the server to provide a persistent reply cache.
	For sessions in which only idempotent operations		For sessions in which only idempotent operations
	will be used (e.g., a read-only session), clients		will be used (e.g., a read-only session), clients
	SHOULD NOT set CREATE_SESSION4_FLAG_PERSIST. If		<bcp14>SHOULD NOT</bcp14> set CREATE_SESSION4_FLAG_PERSIST. If
	the server does not or cannot provide a persistent reply cache,		the server does not or cannot provide a persistent reply cache,
	the server MUST NOT set CREATE_SESSION4_FLAG_PERSIST in		the server <bcp14>MUST NOT</bcp14> set CREATE_SESSION4_FLAG_PERSIST i n
	the field csr_flags.		the field csr_flags.
			</t>
	<vspace blankLines='1' />		<t>
	If the server is a pNFS metadata server, for		If the server is a pNFS metadata server, for
	reasons described in <xref target="obtaining_layout" />		reasons described in <xref target="obtaining_layout" format="default
	it SHOULD support CREATE_SESSION4_FLAG_PERSIST if it		"/>
	supports the layout_hint (<xref target="attrdef_layout_hint" />)		it <bcp14>SHOULD</bcp14> support CREATE_SESSION4_FLAG_PERSIST if it
			supports the layout_hint (<xref target="attrdef_layout_hint" format=
			"default"/>)
	attribute.		attribute.
			</t>
			</dd>
	</t>		<dt>CREATE_SESSION4_FLAG_CONN_BACK_CHAN:</dt>
	<t hangText="CREATE_SESSION4_FLAG_CONN_BACK_CHAN:"/>		<dd>
	<t>
	If CREATE_SESSION4_FLAG_CONN_BACK_CHAN is set in csa_flags,		If CREATE_SESSION4_FLAG_CONN_BACK_CHAN is set in csa_flags,
	the client is requesting that the connection over which the		the client is requesting that the connection over which the
	CREATE_SESSION operation arrived be associated with the session's		CREATE_SESSION operation arrived be associated with the session's
	backchannel in addition to its fore channel.		backchannel in addition to its fore channel.
	If the server agrees, it		If the server agrees, it
	sets CREATE_SESSION4_FLAG_CONN_BACK_CHAN		sets CREATE_SESSION4_FLAG_CONN_BACK_CHAN
	in the result field csr_flags. If		in the result field csr_flags. If
	CREATE_SESSION4_FLAG_CONN_BACK_CHAN is not set in csa_flags,		CREATE_SESSION4_FLAG_CONN_BACK_CHAN is not set in csa_flags,
	then CREATE_SESSION4_FLAG_CONN_BACK_CHAN MUST NOT be set		then CREATE_SESSION4_FLAG_CONN_BACK_CHAN <bcp14>MUST NOT</bcp14> be set
	in csr_flags.		in csr_flags.
			</dd>
	</t>		<dt>CREATE_SESSION4_FLAG_CONN_RDMA:</dt>
	<t hangText="CREATE_SESSION4_FLAG_CONN_RDMA:"/>		<dd>
	<t>
	If CREATE_SESSION4_FLAG_CONN_RDMA is set in csa_flags,		If CREATE_SESSION4_FLAG_CONN_RDMA is set in csa_flags,
	and if the connection over which the CREATE_SESSION operation		and if the connection over which the CREATE_SESSION operation
	arrived		arrived
	is currently in non-RDMA mode but		is currently in non-RDMA mode but
	has the capability to operate in RDMA mode, then the client		has the capability to operate in RDMA mode, then the client
	is requesting that the server "step up" to RDMA mode		is requesting that the server "step up" to RDMA mode
	on the connection.		on the connection.
	If the server agrees, it sets		If the server agrees, it sets
	CREATE_SESSION4_FLAG_CONN_RDMA in the result		CREATE_SESSION4_FLAG_CONN_RDMA in the result
	field csr_flags. If CREATE_SESSION4_FLAG_CONN_RDMA is		field csr_flags. If CREATE_SESSION4_FLAG_CONN_RDMA is
	not set in csa_flags, then CREATE_SESSION4_FLAG_CONN_RDMA MUST		not set in csa_flags, then CREATE_SESSION4_FLAG_CONN_RDMA <bcp14>MUS
	NOT be set in csr_flags.		T
			NOT</bcp14> be set in csr_flags.
	Note that once the server agrees to step up, it and the client		Note that once the server agrees to step up, it and the client
	MUST exchange all future traffic on the connection with RPC RDMA		<bcp14>MUST</bcp14> exchange all future traffic on the connection wi
	framing and not Record Marking (<xref target="RFC8166" />).		th RPC RDMA
	</t>		framing and not Record Marking (<xref target="RFC8166" format="defau
	</list>		lt"/>).
	</t>		</dd>
	<t hangText="csa_fore_chan_attrs, csa_fore_chan_attrs:"/>		</dl>
	<t>		</dd>
			<dt>csa_fore_chan_attrs, csa_back_chan_attrs:</dt>
			<dd>
			<t>
	The csa_fore_chan_attrs and csa_back_chan_attrs		The csa_fore_chan_attrs and csa_back_chan_attrs
	fields apply to attributes of the		fields apply to attributes of the
	fore channel (which conveys		fore channel (which conveys
	requests originating from the client to the server),		requests originating from the client to the server),
	and the backchannel (the channel that conveys		and the backchannel (the channel that conveys
	callback requests originating from the		callback requests originating from the
	server to the client), respectively. The results are in corresponding structures		server to the client), respectively. The results are in corresponding structures
	called csr_fore_chan_attrs and csr_back_chan_attrs.		called csr_fore_chan_attrs and csr_back_chan_attrs.
	The results establish attributes for each channel, and		The results establish attributes for each channel, and
	on all subsequent use of each channel of the session.		on all subsequent use of each channel of the session.
	Each structure has the following fields:		Each structure has the following fields:
	<list style="hanging">		</t>
	<t hangText="ca_headerpadsize:"/>
	<t>		<dl newline="true" spacing="normal">
			<dt>ca_headerpadsize:</dt>
			<dd>
			<t>
	The maximum amount of padding the requester is willing to apply		The maximum amount of padding the requester is willing to apply
	to ensure that write payloads are aligned on some boundary at		to ensure that write payloads are aligned on some boundary at
	the replier. For each channel, the server		the replier. For each channel, the server
	<list style="symbols">		</t>
			<ul spacing="normal">
	<t>		<li>
	will reply in ca_headerpadsize with		will reply in ca_headerpadsize with
	its preferred value,		its preferred value,
	or zero if padding is not in use, and		or zero if padding is not in use, and
	</t>		</li>
			<li>
	<t>		<bcp14>MAY</bcp14> decrease this value but <bcp14>MUST NOT</bcp14>
	MAY decrease this value but MUST NOT increase it.		increase it.
	</t>		</li>
	</list>		</ul>
	</t>		</dd>
	<t hangText="ca_maxrequestsize:"/>		<dt>ca_maxrequestsize:</dt>
	<t>		<dd>
	The maximum size of a COMPOUND or CB_COMPOUND request that		The maximum size of a COMPOUND or CB_COMPOUND request that
	will be sent. This size represents the XDR encoded size of		will be sent. This size represents the XDR encoded size of
	the request, including the RPC headers (including		the request, including the RPC headers (including
	security flavor credentials and verifiers)		security flavor credentials and verifiers)
	but excludes any RPC transport framing headers.		but excludes any RPC transport framing headers.
	Imagine a request coming over a non-RDMA TCP/IP connection, and		Imagine a request coming over a non-RDMA TCP/IP connection, and
	that it has a single Record Marking header preceding		that it has a single Record Marking header preceding
	it. The maximum allowable		it. The maximum allowable
	count encoded in the header will be		count encoded in the header will be
	ca_maxrequestsize. If a requester sends		ca_maxrequestsize. If a requester sends
	a request that exceeds ca_maxrequestsize, the error		a request that exceeds ca_maxrequestsize, the error
	NFS4ERR_REQ_TOO_BIG will be returned per the description in		NFS4ERR_REQ_TOO_BIG will be returned per the description in
	<xref target="COMPOUND_Sizing_Issues" />.		<xref target="COMPOUND_Sizing_Issues" format="default"/>.
	For each channel,		For each channel,
	the server MAY decrease this value but MUST NOT increase it.		the server <bcp14>MAY</bcp14> decrease this value but <bcp14>MUST NO T</bcp14> increase it.
	</t>		</dd>
	<t hangText="ca_maxresponsesize:"/>		<dt>ca_maxresponsesize:</dt>
	<t>		<dd>
	The maximum size of a COMPOUND or CB_COMPOUND reply that		The maximum size of a COMPOUND or CB_COMPOUND reply that
	the requester will		the requester will
	accept from the replier including RPC headers (see		accept from the replier including RPC headers (see
	the ca_maxrequestsize definition).		the ca_maxrequestsize definition).
	For each channel, the server MAY decrease this value, but MUST		For each channel, the server <bcp14>MAY</bcp14> decrease this value,
	NOT increase it.		but <bcp14>MUST
			NOT</bcp14> increase it.
	However, if the client selects a value for		However, if the client selects a value for
	ca_maxresponsesize such that a replier on a channel could		ca_maxresponsesize such that a replier on a channel could
	never send a response, the server SHOULD return		never send a response, the server <bcp14>SHOULD</bcp14> return
	NFS4ERR_TOOSMALL in the CREATE_SESSION reply.		NFS4ERR_TOOSMALL in the CREATE_SESSION reply.
	After the session is created, if a requester sends a		After the session is created, if a requester sends a
	request for which the size of the reply would exceed		request for which the size of the reply would exceed
	this value, the replier will return NFS4ERR_REP_TOO_BIG,		this value, the replier will return NFS4ERR_REP_TOO_BIG,
	per the description in		per the description in
	<xref target="COMPOUND_Sizing_Issues" />.		<xref target="COMPOUND_Sizing_Issues" format="default"/>.
	</t>		</dd>
	<t hangText="ca_maxresponsesize_cached:"/>		<dt>ca_maxresponsesize_cached:</dt>
	<t>		<dd>
	Like ca_maxresponsesize, but the maximum size of a reply		Like ca_maxresponsesize, but the maximum size of a reply
	that will be stored in the reply cache		that will be stored in the reply cache
	(<xref target="Slot_Identifiers_and_Server_Reply_Cache" />).		(<xref target="Slot_Identifiers_and_Server_Reply_Cache" format="defa ult"/>).
	For each channel, the server MAY decrease this value, but MUST		For each channel, the server <bcp14>MAY</bcp14> decrease this
	NOT increase it.		value, but <bcp14>MUST NOT</bcp14> increase it.
	If, in the reply to CREATE_SESSION, the value of		If, in the reply to CREATE_SESSION, the value of
	ca_maxresponsesize_cached of a channel is less than the value		ca_maxresponsesize_cached of a channel is less than the value
	of ca_maxresponsesize of the same channel, then this is an		of ca_maxresponsesize of the same channel, then this is an
	indication to the requester that it needs to be selective		indication to the requester that it needs to be selective
	about which replies it directs the replier to cache; for		about which replies it directs the replier to cache; for
	example, large replies from nonidempotent operations (e.g.,		example, large replies from non-idempotent operations (e.g.,
	COMPOUND requests with a READ operation) should not be		COMPOUND requests with a READ operation) should not be
	cached. The requester decides which replies to cache via an		cached. The requester decides which replies to cache via an
	argument to the SEQUENCE (the sa_cachethis field, see <xref		argument to the SEQUENCE (the sa_cachethis field, see <xref target="
	target="OP_SEQUENCE" />) or CB_SEQUENCE (the csa_cachethis		OP_SEQUENCE" format="default"/>) or CB_SEQUENCE (the csa_cachethis
	field, see <xref target="OP_CB_SEQUENCE" />) operations.		field, see <xref target="OP_CB_SEQUENCE" format="default"/>) operati
			ons.
	After the session is created, if a requester sends a		After the session is created, if a requester sends a
	request for which the size of the reply would exceed		request for which the size of the reply would exceed
	ca_maxresponsesize_cached, the replier will return		ca_maxresponsesize_cached, the replier will return
	NFS4ERR_REP_TOO_BIG_TO_CACHE, per the description in <xref		NFS4ERR_REP_TOO_BIG_TO_CACHE, per the description in <xref target="C
	target="COMPOUND_Sizing_Issues" />.		OMPOUND_Sizing_Issues" format="default"/>.
	</t>		</dd>
	<t hangText="ca_maxoperations:"/>		<dt>ca_maxoperations:</dt>
	<t>		<dd>
	The maximum number of operations the replier		The maximum number of operations the replier
	will accept in a COMPOUND or CB_COMPOUND.		will accept in a COMPOUND or CB_COMPOUND.
	For the backchannel, the server MUST NOT change the value the		For the backchannel, the server <bcp14>MUST NOT</bcp14> change the v alue the
	client offers. For the fore channel, the server		client offers. For the fore channel, the server
	MAY change the requested value.		<bcp14>MAY</bcp14> change the requested value.
	After the session is created, if a requester sends a		After the session is created, if a requester sends a
	COMPOUND or CB_COMPOUND		COMPOUND or CB_COMPOUND
	with more operations than ca_maxoperations,		with more operations than ca_maxoperations,
	the replier MUST return NFS4ERR_TOO_MANY_OPS.		the replier <bcp14>MUST</bcp14> return NFS4ERR_TOO_MANY_OPS.
	</t>		</dd>
	<t hangText="ca_maxrequests:"/>		<dt>ca_maxrequests:</dt>
	<t>		<dd>
	The maximum number of concurrent COMPOUND or CB_COMPOUND		The maximum number of concurrent COMPOUND or CB_COMPOUND
	requests the requester will send on the session. Subsequent		requests the requester will send on the session. Subsequent
	requests will each be assigned a slot identifier by the requester		requests will each be assigned a slot identifier by the requester
	within the range zero to ca_maxrequests - 1 inclusive.		within the range zero to ca_maxrequests - 1 inclusive.
	For the backchannel, the server MUST NOT change the value the		For the backchannel, the server <bcp14>MUST NOT</bcp14> change the v alue the
	client offers. For the fore channel, the server		client offers. For the fore channel, the server
	MAY change the requested value.		<bcp14>MAY</bcp14> change the requested value.
	</t>		</dd>
	<t hangText="ca_rdma_ird:"/>		<dt>ca_rdma_ird:</dt>
	<t>		<dd>
	This array has a maximum of one element.		This array has a maximum of one element.
	If this array has one element, then the element contains the		If this array has one element, then the element contains the
	inbound RDMA read queue depth (IRD).		inbound RDMA read queue depth (IRD).
	For each channel, the server MAY decrease this value, but MUST		For each channel, the server <bcp14>MAY</bcp14> decrease this value,
	NOT increase it.		but <bcp14>MUST
	</t>		NOT</bcp14> increase it.
	</list>		</dd></dl></dd>
	</t>
	<t hangText="csa_cb_program"/>		<dt>csa_cb_program</dt>
	<t>		<dd>
	This is the ONC RPC program number the server MUST use in		This is the ONC RPC program number the server <bcp14>MUST</bcp14> use
			in
	any callbacks sent through the backchannel to the client.		any callbacks sent through the backchannel to the client.
	The server MUST specify an ONC RPC program number equal to		The server <bcp14>MUST</bcp14> specify an ONC RPC program number equal to
	csa_cb_program and an ONC RPC version number equal to 4 in		csa_cb_program and an ONC RPC version number equal to 4 in
	callbacks sent to the client. If a CB_COMPOUND is		callbacks sent to the client. If a CB_COMPOUND is
	sent to the client, the server MUST use a minor version		sent to the client, the server <bcp14>MUST</bcp14> use a minor version
	number of 1.		number of 1.
	There is no corresponding result.		There is no corresponding result.
	</t>		</dd>
	<t hangText="csa_sec_parms"/>		<dt>csa_sec_parms</dt>
	<t>		<dd>
			<t>
	The field csa_sec_parms is an array of acceptable		The field csa_sec_parms is an array of acceptable
	security credentials the server can use on		security credentials the server can use on
	the session's backchannel. Three security		the session's backchannel. Three security
	flavors are supported: AUTH_NONE, AUTH_SYS,		flavors are supported: AUTH_NONE, AUTH_SYS,
	and RPCSEC_GSS. If AUTH_NONE is specified for		and RPCSEC_GSS. If AUTH_NONE is specified for
	a credential, then this says the client is		a credential, then this says the client is
	authorizing the server to use AUTH_NONE on		authorizing the server to use AUTH_NONE on
	all callbacks for the session. If AUTH_SYS		all callbacks for the session. If AUTH_SYS
	is specified, then the client is authorizing		is specified, then the client is authorizing
	the server to use AUTH_SYS on all callbacks,		the server to use AUTH_SYS on all callbacks,
	using the credential specified cbsp_sys_cred. If		using the credential specified cbsp_sys_cred. If
	RPCSEC_GSS is specified, then the server is		RPCSEC_GSS is specified, then the server is
	allowed to use the RPCSEC_GSS context specified		allowed to use the RPCSEC_GSS context specified
	in cbsp_gss_parms as the RPCSEC_GSS context in		in cbsp_gss_parms as the RPCSEC_GSS context in
	the credential of the RPC header of callbacks		the credential of the RPC header of callbacks
	to the client.		to the client.
	There is no corresponding result.		There is no corresponding result.
			</t>
	<vspace blankLines='1' />		<t>
	The RPCSEC_GSS context for the backchannel is specified via		The RPCSEC_GSS context for the backchannel is specified via
	a pair of values of data type		a pair of values of data type
	gsshandle4_t. The data type gsshandle4_t represents an		gsshandle4_t. The data type gsshandle4_t represents an
	RPCSEC_GSS handle, and is		RPCSEC_GSS handle, and is
	precisely the same as the data type of the "handle" field of		precisely the same as the data type of the "handle" field of
	the rpc_gss_init_res data type defined in		the rpc_gss_init_res data type defined in "Context Creation Response
	Section 5.2.3.1, "Context Creation Response -		- Successful Acceptance", <xref target="RFC2203" sectionFormat="of" sec
	Successful Acceptance", of <xref target="RFC2203"		tion="5.2.3.1"/>.
	/>.		</t>
			<t>
	<vspace blankLines='1' />
	The first RPCSEC_GSS handle, gcbp_handle_from_server,		The first RPCSEC_GSS handle, gcbp_handle_from_server,
	is the fore handle the server returned to		is the fore handle the server returned to
	the client (either in the handle field of data type		the client (either in the handle field of data type
	rpc_gss_init_res or as one of the elements of the spi_handles		rpc_gss_init_res or as one of the elements of the spi_handles
	field returned in the reply to EXCHANGE_ID) when the RPCSEC_GSS contex t		field returned in the reply to EXCHANGE_ID) when the RPCSEC_GSS contex t
	was created on the server. The second handle,		was created on the server. The second handle,
	gcbp_handle_from_client, is the back handle to which the		gcbp_handle_from_client, is the back handle to which the
	client will map the RPCSEC_GSS context. The		client will map the RPCSEC_GSS context. The
	server can immediately use the value of		server can immediately use the value of
	gcbp_handle_from_client in the RPCSEC_GSS credential		gcbp_handle_from_client in the RPCSEC_GSS credential
	in callback RPCs. That is, the value in		in callback RPCs. That is, the value in
	gcbp_handle_from_client can be used as the		gcbp_handle_from_client can be used as the
	value of the field "handle" in data type		value of the field "handle" in data type
	rpc_gss_cred_t (see Section 5, "Elements of		rpc_gss_cred_t (see "Elements of
	the RPCSEC_GSS Security Protocol", of <xref		the RPCSEC_GSS Security Protocol", <xref target="RFC2203" sectionForma
	target="RFC2203" />) in callback RPCs.		t="of" section="5"/>) in callback RPCs.
	The server MUST use the RPCSEC_GSS security service		The server <bcp14>MUST</bcp14> use the RPCSEC_GSS security service
	specified in gcbp_service, i.e., it MUST set the		specified in gcbp_service, i.e., it <bcp14>MUST</bcp14> set the
	"service" field of the rpc_gss_cred_t data type in		"service" field of the rpc_gss_cred_t data type in
	RPCSEC_GSS credential to the value of gcbp_service (see		RPCSEC_GSS credential to the value of gcbp_service (see
	Section 5.3.1, "RPC Request Header", of <xref target="RFC2203" />).		"RPC Request Header", <xref target="RFC2203" sectionFormat="of" sectio
			n="5.3.1"/>).
	<vspace blankLines='1' />		</t>
			<t>
	If the RPCSEC_GSS handle identified by		If the RPCSEC_GSS handle identified by
	gcbp_handle_from_server does not exist on the server,		gcbp_handle_from_server does not exist on the server,
	the server will return NFS4ERR_NOENT.		the server will return NFS4ERR_NOENT.
			</t>
	<vspace blankLines='1' />		<t>
			Within each element of csa_sec_parms, the fore and back RPCSEC_GSS con
	Within each element of csa_sec_parms, the fore and back RPCSEC_GSS con		texts <bcp14>MUST</bcp14>
	texts MUST
	share the same GSS context		share the same GSS context
	and MUST have the same seq_window		and <bcp14>MUST</bcp14> have the same seq_window
	(see Section 5.2.3.1 of <xref target="RFC2203">RFC2203</xref>).		(see Section <xref target="RFC2203" sectionFormat="bare" section="5.2.
			3.1"/>
			of RFC 2203 <xref target="RFC2203" format="default"/>).
	The fore and back RPCSEC_GSS context state		The fore and back RPCSEC_GSS context state
	are independent of each other as far as the		are independent of each other as far as the
	RPCSEC_GSS sequence number (see the seq_num		RPCSEC_GSS sequence number (see the seq_num
	field in the rpc_gss_cred_t data type of Sections		field in the rpc_gss_cred_t data type of Sections
	5 and 5.3.1 of <xref target="RFC2203" />).		<xref target="RFC2203" sectionFormat="bare" section="5"/> and
	<vspace blankLines='1' />		<xref target="RFC2203" sectionFormat="bare" section="5.3.1"/> of
	If an RPCSEC_GSS handle is using the SSV context (see <xref		<xref target="RFC2203" format="default"/>).
	target="ssv_mech"/>), then because each SSV RPCSEC_GSS		</t>
			<t>
			If an RPCSEC_GSS handle is using the SSV context (see <xref target="ssv_m
			ech" format="default"/>), then because each SSV RPCSEC_GSS
	handle shares a common SSV GSS context, there are security		handle shares a common SSV GSS context, there are security
	considerations specific to this situation discussed in <xref		considerations specific to this situation discussed in <xref target="rpcs
	target="rpcsec_ssv_consider"/>.		ec_ssv_consider" format="default"/>.
	<vspace blankLines='1' />		</t>
			</dd>
	</t>		</dl>
	</list>		<t>
	</t>
	<t>
	Once the session is created, the first SEQUENCE or		Once the session is created, the first SEQUENCE or
	CB_SEQUENCE received on a slot MUST have a sequence		CB_SEQUENCE received on a slot <bcp14>MUST</bcp14> have a sequence
	ID equal to 1; if not, the replier MUST return		ID equal to 1; if not, the replier <bcp14>MUST</bcp14> return
	NFS4ERR_SEQ_MISORDERED.		NFS4ERR_SEQ_MISORDERED.
			</t>
	</t>		</section>
	</section>		<section toc="exclude" anchor="OP_CREATE_SESSION_IMPLEMENTATION" numbere
	<section toc="exclude" anchor="OP_CREATE_SESSION_IMPLEMENTATION" title="IMPLEM		d="true">
	ENTATION">		<name>IMPLEMENTATION</name>
	<t>		<t>
	To describe a possible implementation, the same notation for client		To describe a possible implementation, the same notation for client
	records introduced in the description of EXCHANGE_ID is used		records introduced in the description of EXCHANGE_ID is used
	with the following addition:		with the following addition:
	<list style="empty">		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	clientid_arg:		clientid_arg:
	The value of the csa_clientid field of the CREATE_SESSION4args		The value of the csa_clientid field of the CREATE_SESSION4args
	structure of the current request.		structure of the current request.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Since CREATE_SESSION is a non-idempotent operation, we		Since CREATE_SESSION is a non-idempotent operation, we
	need to consider the possibility that retries may occur		need to consider the possibility that retries may occur
	as a result of a client restart, network partition,		as a result of a client restart, network partition,
	malfunctioning router, etc. For each client ID		malfunctioning router, etc. For each client ID
	created by EXCHANGE_ID, the server maintains a		created by EXCHANGE_ID, the server maintains a
	separate reply cache (called the CREATE_SESSION reply cache)		separate reply cache (called the CREATE_SESSION reply cache)
	similar to the session reply		similar to the session reply
	cache used for SEQUENCE operations, with two		cache used for SEQUENCE operations, with two
	distinctions.		distinctions.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	First, this is a reply cache just for		First, this is a reply cache just for
	detecting and processing CREATE_SESSION requests for a		detecting and processing CREATE_SESSION requests for a
	given client ID.		given client ID.
	</t>		</li>
	<t>		<li>
	Second, the size of the client ID		Second, the size of the client ID
	reply cache is of one slot (and as a result, the		reply cache is of one slot (and as a result, the
	CREATE_SESSION request does not carry a slot number).		CREATE_SESSION request does not carry a slot number).
	This means that at most one CREATE_SESSION request for		This means that at most one CREATE_SESSION request for
	a given client ID can be outstanding.		a given client ID can be outstanding.
	</t>		</li>
	</list>		</ul>
			<t>
	As previously stated, CREATE_SESSION can be sent with		As previously stated, CREATE_SESSION can be sent with
	or without a preceding SEQUENCE operation. Even if a		or without a preceding SEQUENCE operation. Even if a
	SEQUENCE precedes CREATE_SESSION, the server MUST		SEQUENCE precedes CREATE_SESSION, the server <bcp14>MUST</bcp14>
	maintain the CREATE_SESSION reply cache, which		maintain the CREATE_SESSION reply cache, which
	is separate from the reply cache for the session		is separate from the reply cache for the session
	associated with a SEQUENCE. If CREATE_SESSION was		associated with a SEQUENCE. If CREATE_SESSION was
	originally sent by itself, the client MAY send		originally sent by itself, the client <bcp14>MAY</bcp14> send
	a retry of the CREATE_SESSION operation within a		a retry of the CREATE_SESSION operation within a
	COMPOUND preceded by a SEQUENCE. If CREATE_SESSION		COMPOUND preceded by a SEQUENCE. If CREATE_SESSION
	was originally sent in a COMPOUND that started with a		was originally sent in a COMPOUND that started with a
	SEQUENCE, then the client SHOULD send a retry in		SEQUENCE, then the client <bcp14>SHOULD</bcp14> send a retry in
	a COMPOUND that starts with a SEQUENCE that has the		a COMPOUND that starts with a SEQUENCE that has the
	same session ID as the SEQUENCE of the original		same session ID as the SEQUENCE of the original
	request. However, the client MAY send a retry in a		request. However, the client <bcp14>MAY</bcp14> send a retry in a
	COMPOUND that either has no preceding SEQUENCE, or		COMPOUND that either has no preceding SEQUENCE, or
	has a preceding SEQUENCE that refers to a different		has a preceding SEQUENCE that refers to a different
	session than the original CREATE_SESSION. This might		session than the original CREATE_SESSION. This might
	be necessary if the client sends a CREATE_SESSION		be necessary if the client sends a CREATE_SESSION
	in a COMPOUND preceded by a SEQUENCE with session		in a COMPOUND preceded by a SEQUENCE with session
	ID X, and session X no longer exists. Regardless, any		ID X, and session X no longer exists. Regardless, any
	retry of CREATE_SESSION, with or without a preceding		retry of CREATE_SESSION, with or without a preceding
	SEQUENCE, MUST use the same value of csa_sequence		SEQUENCE, <bcp14>MUST</bcp14> use the same value of csa_sequence
	as the original.		as the original.
	</t>		</t>
			<t>
	<t>
	After the client received a reply to an EXCHANGE_ID operation that contain s		After the client received a reply to an EXCHANGE_ID operation that contain s
	a new, unconfirmed client ID,		a new, unconfirmed client ID,
	the server expects the client to follow		the server expects the client to follow
	with a CREATE_SESSION operation to confirm the client ID. The		with a CREATE_SESSION operation to confirm the client ID. The
	server expects value of csa_sequenceid in the arguments to		server expects value of csa_sequenceid in the arguments to
	that CREATE_SESSION to be		that CREATE_SESSION to be
	to equal the value of the field eir_sequenceid that was returned in		to equal the value of the field eir_sequenceid that was returned in
	results of the EXCHANGE_ID that returned the unconfirmed		results of the EXCHANGE_ID that returned the unconfirmed
	client ID.		client ID.
	Before the server replies to that EXCHANGE_ID operation,		Before the server replies to that EXCHANGE_ID operation,
	it initializes the client ID slot to be equal		it initializes the client ID slot to be equal
	to eir_sequenceid - 1 (accounting for underflow),		to eir_sequenceid - 1 (accounting for underflow),
	and records a contrived CREATE_SESSION result		and records a contrived CREATE_SESSION result
	with a "cached" result of NFS4ERR_SEQ_MISORDERED.		with a "cached" result of NFS4ERR_SEQ_MISORDERED.
	With the client ID slot thus initialized, the processing of the		With the client ID slot thus initialized, the processing of the
	CREATE_SESSION operation is divided into four phases:		CREATE_SESSION operation is divided into four phases:
	<list style="numbers">		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	Client record look up. The server looks up the client ID		Client record look up. The server looks up the client ID
	in its client record table.		in its client record table.
	If the server contains no records		If the server contains no records
	with client ID equal to clientid_arg, then most		with client ID equal to clientid_arg, then most
	likely the client's state has been purged during a		likely the client's state has been purged during a
	period of inactivity, possibly due to a loss of		period of inactivity, possibly due to a loss of
	connectivity. NFS4ERR_STALE_CLIENTID is returned,		connectivity. NFS4ERR_STALE_CLIENTID is returned,
	and no changes are made to any client records on		and no changes are made to any client records on
	the server. Otherwise, the server goes to phase 2.		the server. Otherwise, the server goes to phase 2.
	</t>		</li>
	<t>		<li>
	Sequence ID processing. If csa_sequenceid is equal to the		Sequence ID processing. If csa_sequenceid is equal to the
	sequence ID in the client ID's slot, then this is a replay		sequence ID in the client ID's slot, then this is a replay
	of the previous CREATE_SESSION request, and the server		of the previous CREATE_SESSION request, and the server
	returns the cached result.		returns the cached result.
	If csa_sequenceid is not equal to the sequence ID in the slot,		If csa_sequenceid is not equal to the sequence ID in the slot,
	and is more than one greater (accounting for wraparound),		and is more than one greater (accounting for wraparound),
	then the server returns the error NFS4ERR_SEQ_MISORDERED,		then the server returns the error NFS4ERR_SEQ_MISORDERED,
	and does not change the slot. If csa_sequenceid is		and does not change the slot. If csa_sequenceid is
	equal to the slot's sequence ID + 1 (accounting for		equal to the slot's sequence ID + 1 (accounting for
	wraparound), then the slot's sequence ID is set to		wraparound), then the slot's sequence ID is set to
	csa_sequenceid, and the CREATE_SESSION processing goes to		csa_sequenceid, and the CREATE_SESSION processing goes to
	the next phase. A subsequent new CREATE_SESSION call		the next phase. A subsequent new CREATE_SESSION call
	over the same client ID MUST		over the same client ID <bcp14>MUST</bcp14>
	use a csa_sequenceid that is one greater than the		use a csa_sequenceid that is one greater than the
	sequence ID in the slot.		sequence ID in the slot.
	</t>		</li>
	<t>		<li>
			<t>
	Client ID confirmation. If this would be the first session for the		Client ID confirmation. If this would be the first session for the
	client ID, the CREATE_SESSION operation serves to confirm the		client ID, the CREATE_SESSION operation serves to confirm the
	client ID.		client ID.
	Otherwise,		Otherwise,
	the client ID confirmation phase is skipped and only		the client ID confirmation phase is skipped and only
	the session creation phase occurs.		the session creation phase occurs.
	Any case in which there is more than one		Any case in which there is more than one
	record with identical values for client ID represents		record with identical values for client ID represents
	a server implementation error.		a server implementation error.
	Operation in the		Operation in the
	potential valid cases is summarized as follows.		potential valid cases is summarized as follows.
	<list style="symbols">		</t>
	<t>Successful Confirmation		<ul spacing="normal">
	<list style="empty">		<li>
	<t>		<t>Successful Confirmation
			</t>
			<ul empty="true" spacing="normal">
			<li>
	If the server has the following unconfirmed record, then this		If the server has the following unconfirmed record, then this
	is the expected confirmation of an unconfirmed record.		is the expected confirmation of an unconfirmed record.
	</t>		</li>
	<t>		<li>
	{ ownerid, verifier, principal_arg, clientid_arg, unconfirmed }		{ ownerid, verifier, principal_arg, clientid_arg, unconfirmed }
	</t>		</li>
	<t>		<li>
	As noted in <xref target="OP_EXCHANGE_ID_IMPLEMENTATION" />,		As noted in <xref target="OP_EXCHANGE_ID_IMPLEMENTATION" format="def
			ault"/>,
	the server might also have the following confirmed record.		the server might also have the following confirmed record.
	</t>		</li>
	<t>		<li>
	{ ownerid, old_verifier, principal_arg, old_clientid, confirmed }		{ ownerid, old_verifier, principal_arg, old_clientid, confirmed }
	</t>		</li>
	<t>		<li>
	The server schedules the replacement of both records with:		The server schedules the replacement of both records with:
	</t>		</li>
	<t>		<li>
	{ ownerid, verifier, principal_arg, clientid_arg, confirmed }		{ ownerid, verifier, principal_arg, clientid_arg, confirmed }
	</t>		</li>
	<t>		<li>
	The processing of CREATE_SESSION continues on to session creation.		The processing of CREATE_SESSION continues on to session creation.
	Once the session is successfully created, the scheduled client		Once the session is successfully created, the scheduled client
	record replacement is committed. If the session is not		record replacement is committed. If the session is not
	successfully created, then no changes are made to any client		successfully created, then no changes are made to any client
	records on the server.		records on the server.
	</t>		</li>
	</list>		</ul>
	</t>		</li>
			<li>
	<t>Unsuccessful Confirmation		<t>Unsuccessful Confirmation
	<list style="empty">		</t>
	<t>		<ul empty="true" spacing="normal">
			<li>
	If the server has the following record, then the client has		If the server has the following record, then the client has
	changed principals after the previous EXCHANGE_ID request,		changed principals after the previous EXCHANGE_ID request,
	or there has been a chance collision between shorthand client		or there has been a chance collision between shorthand client
	identifiers.		identifiers.
	</t>		</li>
	<t>		<li>
	{ *, *, old_principal_arg, clientid_arg, * }		{ *, *, old_principal_arg, clientid_arg, * }
	</t>		</li>
	<t>		<li>
	Neither of these cases is permissible. Processing stops and		Neither of these cases is permissible. Processing stops and
	NFS4ERR_CLID_INUSE is returned to the client. No changes are		NFS4ERR_CLID_INUSE is returned to the client. No changes are
	made to any client records on the server.		made to any client records on the server.
	</t>		</li>
	</list>		</ul>
	</t>		</li>
	</list>		</ul>
	</t>		</li>
			<li>
	<t>		<t>
	Session creation.		Session creation.
	The server confirmed the client ID, either in this		The server confirmed the client ID, either in this
	CREATE_SESSION operation, or a previous CREATE_SESSION		CREATE_SESSION operation, or a previous CREATE_SESSION
	operation.		operation.
	The server examines the remaining fields of the arguments.		The server examines the remaining fields of the arguments.
	<vspace blankLines='1' />		</t>
			<t>
	The server creates the session by recording the		The server creates the session by recording the
	parameter values used (including whether the		parameter values used (including whether the
	CREATE_SESSION4_FLAG_PERSIST flag is set and has		CREATE_SESSION4_FLAG_PERSIST flag is set and has
	been accepted by the server) and allocating space		been accepted by the server) and allocating space
	for the session reply cache (if there is not enough		for the session reply cache (if there is not enough
	space, the server returns NFS4ERR_NOSPC). For each slot in the		space, the server returns NFS4ERR_NOSPC). For each slot in the
	reply cache, the server sets the sequence ID to zero,		reply cache, the server sets the sequence ID to zero,
	and records an entry containing a COMPOUND		and records an entry containing a COMPOUND
	reply with zero operations and the error		reply with zero operations and the error
	NFS4ERR_SEQ_MISORDERED. This way, if the first		NFS4ERR_SEQ_MISORDERED. This way, if the first
	SEQUENCE request sent has a sequence ID equal to		SEQUENCE request sent has a sequence ID equal to
	zero, the server can simply return what is in the		zero, the server can simply return what is in the
	reply cache: NFS4ERR_SEQ_MISORDERED. The client		reply cache: NFS4ERR_SEQ_MISORDERED. The client
	initializes its reply cache for receiving callbacks		initializes its reply cache for receiving callbacks
	in the same way, and similarly, the first CB_SEQUENCE		in the same way, and similarly, the first CB_SEQUENCE
	operation on a slot after session creation MUST have		operation on a slot after session creation <bcp14>MUST</bcp14> have
	a sequence ID of one.		a sequence ID of one.
	<vspace blankLines='1' />		</t>
			<t>
	If the session state is created successfully, the server associates		If the session state is created successfully, the server associates
	the session with the client ID provided by the client.		the session with the client ID provided by the client.
	<vspace blankLines='1' />		</t>
			<t>
	When a request that had CREATE_SESSION4_FLAG_CONN_RDMA set		When a request that had CREATE_SESSION4_FLAG_CONN_RDMA set
	needs to be retried, the retry		needs to be retried, the retry
	MUST be done on a new connection that is in non-RDMA mode.		<bcp14>MUST</bcp14> be done on a new connection that is in non-RDMA mode.
	If properties of the new connection are different enough		If properties of the new connection are different enough
	that the arguments to CREATE_SESSION need to change, then		that the arguments to CREATE_SESSION need to change, then
	a non-retry MUST be sent. The server will eventually dispose		a non-retry <bcp14>MUST</bcp14> be sent. The server will eventually dispo se
	of any session that was created on the original connection.		of any session that was created on the original connection.
	</t>		</t>
	</list>		</li>
	</t>		</ol>
	<t>		<t>
	On the backchannel, the client and server might wish to		On the backchannel, the client and server might wish to
	have many slots, in some cases perhaps more that the fore channel, in		have many slots, in some cases perhaps more that the fore channel, in
	order to deal with the situations where the		order to deal with the situations where the
	network link has high latency and is the primary		network link has high latency and is the primary
	bottleneck for response to recalls. If so, and if the		bottleneck for response to recalls. If so, and if the
	client provides too few slots to the backchannel,		client provides too few slots to the backchannel,
	the server might limit the number of recallable		the server might limit the number of recallable
	objects it gives to the client.		objects it gives to the client.
	</t>		</t>
	<t>		<t>
	Implementing RPCSEC_GSS callback support requires		Implementing RPCSEC_GSS callback support requires
	changes to both the client and server implementations of		changes to both the client and server implementations of
	RPCSEC_GSS. One possible set of changes includes:		RPCSEC_GSS. One possible set of changes includes:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	Adding a data structure that wraps the GSS-API		Adding a data structure that wraps the GSS-API
	context with a reference count.		context with a reference count.
	</t>		</li>
	<t>		<li>
	New functions to increment and decrement the reference		New functions to increment and decrement the reference
	count. If the reference count is decremented to zero,		count. If the reference count is decremented to zero,
	the wrapper data structure and the GSS-API context it		the wrapper data structure and the GSS-API context it
	refers to would be freed.		refers to would be freed.
	</t>		</li>
	<t>		<li>
	Change RPCSEC_GSS to create the wrapper data		Change RPCSEC_GSS to create the wrapper data
	structure upon receiving GSS-API context from		structure upon receiving GSS-API context from
	gss_accept_sec_context() and gss_init_sec_context().		gss_accept_sec_context() and gss_init_sec_context().
	The reference count would be initialized to 1.		The reference count would be initialized to 1.
	</t>		</li>
	<t>		<li>
	Adding a function to map an existing		Adding a function to map an existing
	RPCSEC_GSS handle to a pointer to the wrapper data		RPCSEC_GSS handle to a pointer to the wrapper data
	structure. The reference count would be incremented.		structure. The reference count would be incremented.
	</t>		</li>
	<t>		<li>
	Adding a function to create a new RPCSEC_GSS		Adding a function to create a new RPCSEC_GSS
	handle from a pointer to the wrapper data structure.		handle from a pointer to the wrapper data structure.
	The reference count would be incremented.		The reference count would be incremented.
	</t>		</li>
	<t>		<li>
	Replacing calls from RPCSEC_GSS that free GSS-API		Replacing calls from RPCSEC_GSS that free GSS-API
	contexts, with calls to decrement the reference count		contexts, with calls to decrement the reference count
	on the wrapper data structure.		on the wrapper data structure.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="OP_DESTROY_SESSION" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 44: DESTROY_SESSION - Destroy a Session</name>
	$ -->		<section toc="exclude" anchor="OP_DESTROY_SESSION_ARGUMENT" numbered="tr
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		ue">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_DESTROY_SESSION" title="Operation 44: DESTROY_SESSION - Dest		<sourcecode type="xdr"><![CDATA[
	roy a Session" >
	<section toc="exclude" anchor="OP_DESTROY_SESSION_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct DESTROY_SESSION4args {		struct DESTROY_SESSION4args {
	sessionid4 dsa_sessionid;		sessionid4 dsa_sessionid;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_DESTROY_SESSION_RESULT" numbered="true
	</figure>		">
	</section>		<name>RESULT</name>
	<section toc="exclude" anchor="OP_DESTROY_SESSION_RESULT" title="RESULT">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct DESTROY_SESSION4res {		struct DESTROY_SESSION4res {
	nfsstat4 dsr_status;		nfsstat4 dsr_status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_DESTROY_SESSION_DESCRIPTION" numbered=
	</figure>		"true">
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_DESTROY_SESSION_DESCRIPTION" title="DESCRIPT		<t>
	ION">
	<t>
	The DESTROY_SESSION operation closes the session and discards		The DESTROY_SESSION operation closes the session and discards
	the session's reply cache, if any.		the session's reply cache, if any.
	Any remaining connections associated with the session are		Any remaining connections associated with the session are
	immediately disassociated. If the connection has no remaining		immediately disassociated. If the connection has no remaining
	associated sessions, the connection		associated sessions, the connection
	MAY be closed by the server.		<bcp14>MAY</bcp14> be closed by the server.
	Locks, delegations, layouts, wants, and the lease, which are all		Locks, delegations, layouts, wants, and the lease, which are all
	tied to the client ID, are not affected by DESTROY_SESSION.		tied to the client ID, are not affected by DESTROY_SESSION.
	</t>		</t>
	<t>		<t>
	DESTROY_SESSION MUST be invoked on a connection that		DESTROY_SESSION <bcp14>MUST</bcp14> be invoked on a connection that
	is associated with the session being destroyed.		is associated with the session being destroyed.
	In addition, if SP4_MACH_CRED state protection		In addition, if SP4_MACH_CRED state protection
	was specified when the client ID was created,		was specified when the client ID was created,
	the RPCSEC_GSS principal that created the session MUST be		the RPCSEC_GSS principal that created the session <bcp14>MUST</bcp14> be
	the one that destroys the session, using RPCSEC_GSS		the one that destroys the session, using RPCSEC_GSS
	privacy or integrity. If SP4_SSV state protection was		privacy or integrity. If SP4_SSV state protection was
	specified when the client ID was created, RPCSEC_GSS		specified when the client ID was created, RPCSEC_GSS
	using the SSV mechanism (<xref target="ssv_mech" />)		using the SSV mechanism (<xref target="ssv_mech" format="default"/>)
	MUST be used, with integrity or privacy.		<bcp14>MUST</bcp14> be used, with integrity or privacy.
	</t>		</t>
	<t>		<t>
	If the COMPOUND request starts with SEQUENCE, and		If the COMPOUND request starts with SEQUENCE, and
	if the sessionids specified in SEQUENCE and DESTROY_SESSION		if the sessionids specified in SEQUENCE and DESTROY_SESSION
	are the same, then		are the same, then
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	DESTROY_SESSION MUST be the final operation in the COMPOUND		<li>
			DESTROY_SESSION <bcp14>MUST</bcp14> be the final operation in the COMPOUN
			D
	request.		request.
	</t>		</li>
			<li>
	<t>
	It is advisable to avoid placing DESTROY_SESSION in a		It is advisable to avoid placing DESTROY_SESSION in a
	COMPOUND request with other state-modifying		COMPOUND request with other state-modifying
	operations, because the DESTROY_SESSION will destroy		operations, because the DESTROY_SESSION will destroy
	the reply cache.		the reply cache.
	</t>		</li>
			<li>
	<t>
	Because the session and its reply cache are destroyed, a client that		Because the session and its reply cache are destroyed, a client that
	retries the request may receive an error in		retries the request may receive an error in
	reply to the retry, even though the original request was		reply to the retry, even though the original request was
	successful.		successful.
	</t>		</li>
			</ul>
	</list>		<t>
	</t>
	<t>
	If the COMPOUND request starts with SEQUENCE, and		If the COMPOUND request starts with SEQUENCE, and
	if the sessionids specified in SEQUENCE and DESTROY_SESSION		if the sessionids specified in SEQUENCE and DESTROY_SESSION
	are different, then DESTROY_SESSION can appear in any position		are different, then DESTROY_SESSION can appear in any position
	of the COMPOUND request (except for the first position). The		of the COMPOUND request (except for the first position). The
	two sessionids can belong to different client IDs.		two sessionids can belong to different client IDs.
	</t>		</t>
			<t>
	<t>
	If the COMPOUND request does not start with		If the COMPOUND request does not start with
	SEQUENCE, and if DESTROY_SESSION is not the		SEQUENCE, and if DESTROY_SESSION is not the
	sole operation, then server MUST return		sole operation, then server <bcp14>MUST</bcp14> return
	NFS4ERR_NOT_ONLY_OP.		NFS4ERR_NOT_ONLY_OP.
	</t>		</t>
			<t>
	<t>
	If there is a backchannel on the session and the		If there is a backchannel on the session and the
	server has outstanding CB_COMPOUND operations for the		server has outstanding CB_COMPOUND operations for the
	session which have not been replied to, then the server		session which have not been replied to, then the server
	MAY refuse to destroy the session and return an error.		<bcp14>MAY</bcp14> refuse to destroy the session and return an error.
	If so, then		If so, then
	in the event the backchannel is down, the server		in the event the backchannel is down, the server
	SHOULD return NFS4ERR_CB_PATH_DOWN to inform the		<bcp14>SHOULD</bcp14> return NFS4ERR_CB_PATH_DOWN to inform the
	client that the backchannel needs to be repaired before		client that the backchannel needs to be repaired before
	the server will allow the session to be destroyed.		the server will allow the session to be destroyed.
	Otherwise, the error CB_BACK_CHAN_BUSY SHOULD be		Otherwise, the error CB_BACK_CHAN_BUSY <bcp14>SHOULD</bcp14> be
	returned to indicate that there are CB_COMPOUNDs		returned to indicate that there are CB_COMPOUNDs
	that need to be replied to. The client SHOULD reply		that need to be replied to. The client <bcp14>SHOULD</bcp14> reply
	to all outstanding CB_COMPOUNDs before re-sending		to all outstanding CB_COMPOUNDs before re-sending
	DESTROY_SESSION.		DESTROY_SESSION.
	</t>		</t>
	</section>		</section>
			</section>
	</section>		<section anchor="OP_FREE_STATEID" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 45: FREE_STATEID - Free Stateid with No Locks</name>
	$ -->		<section toc="exclude" anchor="OP_FREE_STATEID_ARGUMENT" numbered="true"
	<!-- Copyright (C) The IETF Trust (2007) -->		>
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_FREE_STATEID" title="Operation 45: FREE_STATEID - Free State		<sourcecode type="xdr"><![CDATA[
	id with No Locks" >
	<section toc="exclude" anchor="OP_FREE_STATEID_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct FREE_STATEID4args {		struct FREE_STATEID4args {
	stateid4 fsa_stateid;		stateid4 fsa_stateid;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_FREE_STATID_RESULT" numbered="true">
	</figure>		<name>RESULT</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_FREE_STATID_RESULT" title="RESULT">
	<figure>
	<artwork>
	struct FREE_STATEID4res {		struct FREE_STATEID4res {
	nfsstat4 fsr_status;		nfsstat4 fsr_status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_FREE_STATEID4_DESCRIPTION" numbered="t
	</figure>		rue">
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_FREE_STATEID4_DESCRIPTION" title="DESCRIPTIO		<t>
	N">
	<t>
	The FREE_STATEID operation is used to free a stateid that no longer		The FREE_STATEID operation is used to free a stateid that no longer
	has any associated locks (including opens, byte-range locks, delegations,		has any associated locks (including opens, byte-range locks, delegations,
	and layouts). This may be because of client LOCKU operations or because		and layouts). This may be because of client LOCKU operations or because
	of server revocation. If there are valid locks (of any kind)		of server revocation. If there are valid locks (of any kind)
	associated with the stateid in question, the error NFS4ERR_LOCKS_HELD		associated with the stateid in question, the error NFS4ERR_LOCKS_HELD
	will be returned, and the associated stateid will not be freed.		will be returned, and the associated stateid will not be freed.
	</t>		</t>
	<t>		<t>
	When a stateid is freed that had been associated with revoked locks,		When a stateid is freed that had been associated with revoked locks,
	by sending the FREE_STATEID operation, the client acknowledges the loss of those		by sending the FREE_STATEID operation, the client acknowledges the loss of those
	locks. This allows the server, once all such revoked state is		locks. This allows the server, once all such revoked state is
	acknowledged,		acknowledged,
	to allow that client again to reclaim locks, without encountering		to allow that client again to reclaim locks, without encountering
	the edge conditions discussed in <xref target="server_failure" />.		the edge conditions discussed in <xref target="server_failure" format="def
	</t>		ault"/>.
	<t>		</t>
			<t>
	Once a successful FREE_STATEID is done for a given stateid, any		Once a successful FREE_STATEID is done for a given stateid, any
	subsequent use of that stateid will result in an NFS4ERR_BAD_STATEID		subsequent use of that stateid will result in an NFS4ERR_BAD_STATEID
	error.		error.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="OP_GET_DIR_DELEGATION" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 46: GET_DIR_DELEGATION - Get a Directory Delegation</nam
	$ -->		e>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_GET_DIR_DELEGATION_ARGUMENT" numbered=
	<!-- Copyright (C) The Internet Society (2006) -->		"true">
	<section anchor="OP_GET_DIR_DELEGATION" title="Operation 46: GET_DIR_DELEGATION		<name>ARGUMENT</name>
	- Get a Directory Delegation" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_GET_DIR_DELEGATION_ARGUMENT" title="ARGUMENT
	">
	<figure>
	<artwork>
	typedef nfstime4 attr_notice4;		typedef nfstime4 attr_notice4;
	struct GET_DIR_DELEGATION4args {		struct GET_DIR_DELEGATION4args {
	/* CURRENT_FH: delegated directory */		/* CURRENT_FH: delegated directory */
	bool gdda_signal_deleg_avail;		bool gdda_signal_deleg_avail;
	bitmap4 gdda_notification_types;		bitmap4 gdda_notification_types;
	attr_notice4 gdda_child_attr_delay;		attr_notice4 gdda_child_attr_delay;
	attr_notice4 gdda_dir_attr_delay;		attr_notice4 gdda_dir_attr_delay;
	bitmap4 gdda_child_attributes;		bitmap4 gdda_child_attributes;
	bitmap4 gdda_dir_attributes;		bitmap4 gdda_dir_attributes;
	};		};]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_GET_DIR_DELEGATION_RESULT" numbered="t
	</section>		rue">
	<section toc="exclude" anchor="OP_GET_DIR_DELEGATION_RESULT" title="RESULT">		<name>RESULT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct GET_DIR_DELEGATION4resok {		struct GET_DIR_DELEGATION4resok {
	verifier4 gddr_cookieverf;		verifier4 gddr_cookieverf;
	/* Stateid for get_dir_delegation */		/* Stateid for get_dir_delegation */
	stateid4 gddr_stateid;		stateid4 gddr_stateid;
	/* Which notifications can the server support */		/* Which notifications can the server support */
	bitmap4 gddr_notification;		bitmap4 gddr_notification;
	bitmap4 gddr_child_attributes;		bitmap4 gddr_child_attributes;
	bitmap4 gddr_dir_attributes;		bitmap4 gddr_dir_attributes;
	};		};
	skipping to change at line 37316 ¶		skipping to change at line 37330 ¶
	case GDD4_UNAVAIL:		case GDD4_UNAVAIL:
	bool gddrnf_will_signal_deleg_avail;		bool gddrnf_will_signal_deleg_avail;
	};		};
	union GET_DIR_DELEGATION4res		union GET_DIR_DELEGATION4res
	switch (nfsstat4 gddr_status) {		switch (nfsstat4 gddr_status) {
	case NFS4_OK:		case NFS4_OK:
	GET_DIR_DELEGATION4res_non_fatal gddr_res_non_fatal4;		GET_DIR_DELEGATION4res_non_fatal gddr_res_non_fatal4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_GET_DIR_DELEGATION_DESCRIPTION" number
	</figure>		ed="true">
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_GET_DIR_DELEGATION_DESCRIPTION" title="DESCR		<t>
	IPTION">
	<t>
	The GET_DIR_DELEGATION operation is used by a client to request		The GET_DIR_DELEGATION operation is used by a client to request
	a directory delegation. The directory is represented by the		a directory delegation. The directory is represented by the
	current filehandle. The client also specifies whether it wants		current filehandle. The client also specifies whether it wants
	the server to notify it when the directory changes in certain		the server to notify it when the directory changes in certain
	ways by setting one or more bits in a bitmap. The server may		ways by setting one or more bits in a bitmap. The server may
	refuse to grant the delegation. In that case, the server		refuse to grant the delegation. In that case, the server
	will return NFS4ERR_DIRDELEG_UNAVAIL. If the server decides to		will return NFS4ERR_DIRDELEG_UNAVAIL. If the server decides to
	hand out the delegation, it will return a cookie verifier for		hand out the delegation, it will return a cookie verifier for
	that directory. If the cookie verifier changes when the client		that directory. If the cookie verifier changes when the client
	is holding the delegation, the delegation will be recalled		is holding the delegation, the delegation will be recalled
	unless the client has asked for notification for this event.		unless the client has asked for notification for this event.
	</t>		</t>
	<t>		<t>
	The server will also return a directory delegation stateid,		The server will also return a directory delegation stateid,
	gddr_stateid, as a result of the		gddr_stateid, as a result of the
	GET_DIR_DELEGATION operation. This stateid will appear in		GET_DIR_DELEGATION operation. This stateid will appear in
	callback messages related to the delegation, such as		callback messages related to the delegation, such as
	notifications and delegation recalls. The client will use this		notifications and delegation recalls. The client will use this
	stateid to return the delegation voluntarily or upon recall. A		stateid to return the delegation voluntarily or upon recall. A
	delegation is returned by calling the DELEGRETURN operation.		delegation is returned by calling the DELEGRETURN operation.
	</t>		</t>
	<t>		<t>
	The server might not be able to support notifications of certain		The server might not be able to support notifications of certain
	events. If the client asks for such notifications, the server		events. If the client asks for such notifications, the server
	MUST inform the client of its inability to do so as part of the		<bcp14>MUST</bcp14> inform the client of its inability to do so as part of the
	GET_DIR_DELEGATION reply by not setting the appropriate bits in		GET_DIR_DELEGATION reply by not setting the appropriate bits in
	the supported notifications bitmask, gddr_notification, contained		the supported notifications bitmask, gddr_notification, contained
	in the reply. The server MUST NOT add bits to gddr_notification		in the reply. The server <bcp14>MUST NOT</bcp14> add bits to gddr_notific ation
	that the client did not request.		that the client did not request.
	</t>		</t>
	<t>		<t>
	The GET_DIR_DELEGATION operation can be used for both normal and		The GET_DIR_DELEGATION operation can be used for both normal and
	named attribute directories.		named attribute directories.
	</t>		</t>
	<t>		<t>
	If client sets gdda_signal_deleg_avail to TRUE, then it is		If client sets gdda_signal_deleg_avail to TRUE, then it is
	registering with the client a "want" for a directory		registering with the client a "want" for a directory
	delegation. If the delegation is not available, and the server		delegation. If the delegation is not available, and the server
	supports and will honor the "want",		supports and will honor the "want",
	the results will have gddrnf_will_signal_deleg_avail set to TRUE		the results will have gddrnf_will_signal_deleg_avail set to TRUE
	and no error will be indicated on return.		and no error will be indicated on return.
	If so, the client should expect a future CB_RECALLABLE_OBJ_AVAIL		If so, the client should expect a future CB_RECALLABLE_OBJ_AVAIL
	operation to indicate that a directory delegation is available.		operation to indicate that a directory delegation is available.
	If the server does not wish to honor the "want" or is not able		If the server does not wish to honor the "want" or is not able
	to do so, it returns the error NFS4ERR_DIRDELEG_UNAVAIL. If the		to do so, it returns the error NFS4ERR_DIRDELEG_UNAVAIL. If the
	delegation is immediately available, the server SHOULD return it with		delegation is immediately available, the server <bcp14>SHOULD</bcp14> retu rn it with
	the response to the operation, rather than via a callback.		the response to the operation, rather than via a callback.
	</t>		</t>
			<t>
	<t>
	When a client makes a request for a		When a client makes a request for a
	directory delegation while it already holds		directory delegation while it already holds
	a directory delegation for that directory		a directory delegation for that directory
	(including the case where it has been		(including the case where it has been
	recalled but not yet returned by the client		recalled but not yet returned by the client
	or revoked by the server), the server MUST		or revoked by the server), the server <bcp14>MUST</bcp14>
	reply with the value of gddr_status set to		reply with the value of gddr_status set to
	NFS4_OK, the value of gddrnf_status set to		NFS4_OK, the value of gddrnf_status set to
	GDD4_UNAVAIL, and the value of		GDD4_UNAVAIL, and the value of
	gddrnf_will_signal_deleg_avail set to		gddrnf_will_signal_deleg_avail set to
	FALSE. The delegation the client held		FALSE. The delegation the client held
	before the request remains intact, and its		before the request remains intact, and its
	state is unchanged. The current stateid is		state is unchanged. The current stateid is
	not changed (see <xref		not changed (see <xref target="current_stateid" format="default"/> for a d
	target="current_stateid"/> for a description		escription
	of the current stateid).		of the current stateid).
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_GET_DIR_DELEGATION_IMPLEMENTATION" title="IM		<section toc="exclude" anchor="OP_GET_DIR_DELEGATION_IMPLEMENTATION" num
	PLEMENTATION">		bered="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	Directory delegations provide the benefit of improving cache		Directory delegations provide the benefit of improving cache
	consistency of namespace information. This is done through		consistency of namespace information. This is done through
	synchronous callbacks. A server must support synchronous		synchronous callbacks. A server must support synchronous
	callbacks in order to support directory delegations. In addition		callbacks in order to support directory delegations. In addition
	to that, asynchronous notifications provide a way to reduce		to that, asynchronous notifications provide a way to reduce
	network traffic as well as improve client performance in certain		network traffic as well as improve client performance in certain
	conditions.		conditions.
	</t>		</t>
	<t>		<t>
	Notifications are specified in terms of potential		Notifications are specified in terms of potential
	changes to the directory. A client can ask to be		changes to the directory. A client can ask to be
	notified of events by setting one or more		notified of events by setting one or more
	bits in gdda_notification_types.		bits in gdda_notification_types.
	The client can ask for notifications on addition of entries		The client can ask for notifications on addition of entries
	to a directory (by setting the		to a directory (by setting the
	NOTIFY4_ADD_ENTRY in gdda_notification_types),		NOTIFY4_ADD_ENTRY in gdda_notification_types),
	notifications on entry removal		notifications on entry removal
	(NOTIFY4_REMOVE_ENTRY), renames		(NOTIFY4_REMOVE_ENTRY), renames
	(NOTIFY4_RENAME_ENTRY), directory attribute		(NOTIFY4_RENAME_ENTRY), directory attribute
	changes (NOTIFY4_CHANGE_DIR_ATTRIBUTES),		changes (NOTIFY4_CHANGE_DIR_ATTRIBUTES),
	and cookie verifier changes		and cookie verifier changes
	(NOTIFY4_CHANGE_COOKIE_VERIFIER) by setting		(NOTIFY4_CHANGE_COOKIE_VERIFIER) by setting
	one or more corresponding bits in the		one or more corresponding bits in the
	gdda_notification_types field.		gdda_notification_types field.
	</t>		</t>
	<t>		<t>
	The client can also ask for		The client can also ask for
	notifications of changes to		notifications of changes to
	attributes of directory entries		attributes of directory entries
	(NOTIFY4_CHANGE_CHILD_ATTRIBUTES)		(NOTIFY4_CHANGE_CHILD_ATTRIBUTES)
	in order to keep its attribute cache up to date. However, any		in order to keep its attribute cache up to date. However, any
	changes made to child attributes do not cause the delegation to		changes made to child attributes do not cause the delegation to
	be recalled. If a client is interested in directory entry		be recalled. If a client is interested in directory entry
	caching or negative name caching, it can set the		caching or negative name caching, it can set the
	gdda_notification_types appropriately to its particular need		gdda_notification_types appropriately to its particular need
	and the server will notify it of		and the server will notify it of
	all changes that would otherwise invalidate its name cache. The		all changes that would otherwise invalidate its name cache. The
	kind of notification a client asks for may depend on the		kind of notification a client asks for may depend on the
	directory size, its rate of change, and the applications being		directory size, its rate of change, and the applications being
	used to access that directory. The enumeration of the conditions under		used to access that directory. The enumeration of the conditions under
	which a client might ask for a notification is out of the scope		which a client might ask for a notification is out of the scope
	of this specification.		of this specification.
	</t>		</t>
	<t>		<t>
	For attribute notifications, the client		For attribute notifications, the client
	will set bits in the gdda_dir_attributes		will set bits in the gdda_dir_attributes
	bitmap to indicate which attributes		bitmap to indicate which attributes
	it wants to be notified of. If the server does not support		it wants to be notified of. If the server does not support
	notifications for changes to a certain attribute, it SHOULD NOT		notifications for changes to a certain attribute, it <bcp14>SHOULD NOT</bc p14>
	set that attribute in the supported attribute bitmap		set that attribute in the supported attribute bitmap
	specified in the reply (gddr_dir_attributes). The client will		specified in the reply (gddr_dir_attributes). The client will
	also set in the gdda_child_attributes bitmap the attributes		also set in the gdda_child_attributes bitmap the attributes
	of directory entries it wants to be notified of, and		of directory entries it wants to be notified of, and
	the server will indicate in gddr_child_attributes which		the server will indicate in gddr_child_attributes which
	attributes of directory entries it will notify the client of.		attributes of directory entries it will notify the client of.
	</t>		</t>
	<t>		<t>
	The client will also let the server know if		The client will also let the server know if
	it wants to get the notification as soon as the attribute change		it wants to get the notification as soon as the attribute change
	occurs or after a certain delay by setting a delay factor;		occurs or after a certain delay by setting a delay factor;
	gdda_child_attr_delay is for attribute changes to directory entries and		gdda_child_attr_delay is for attribute changes to directory entries and
	gdda_dir_attr_delay is for attribute changes to the directory. If this		gdda_dir_attr_delay is for attribute changes to the directory. If this
	delay factor is set to zero, that indicates to the server that		delay factor is set to zero, that indicates to the server that
	the client wants to be notified of any attribute changes as soon		the client wants to be notified of any attribute changes as soon
	as they occur. If the delay factor is set to N seconds, the server will		as they occur. If the delay factor is set to N seconds, the server will
	make a best-effort guarantee that attribute updates are		make a best-effort guarantee that attribute updates are
	synchronized within N seconds.		synchronized within N seconds.
	If the client asks		If the client asks
	for a delay factor that the server does not support or that may		for a delay factor that the server does not support or that may
	cause significant resource consumption on the server by causing		cause significant resource consumption on the server by causing
	the server to send a lot of notifications, the server should not		the server to send a lot of notifications, the server should not
	commit to sending out notifications for attributes and		commit to sending out notifications for attributes and
	therefore must not set the appropriate bit in the		therefore must not set the appropriate bit in the
	gddr_child_attributes and gddr_dir_attributes bitmaps in the response.		gddr_child_attributes and gddr_dir_attributes bitmaps in the response.
	</t>		</t>
	<t>		<t>
	The client MUST use a security tuple (<xref		The client <bcp14>MUST</bcp14> use a security tuple (<xref target="NFSv4_S
	target="NFSv4_Security_Tuples"/>) that the		ecurity_Tuples" format="default"/>) that the
	directory or its applicable ancestor (<xref		directory or its applicable ancestor (<xref target="Security_Service_Negot
	target="Security_Service_Negotiation"/>) is		iation" format="default"/>) is
	exported with. If not, the server MUST return		exported with. If not, the server <bcp14>MUST</bcp14> return
	NFS4ERR_WRONGSEC to the operation that both precedes		NFS4ERR_WRONGSEC to the operation that both precedes
	GET_DIR_DELEGATION and sets the current filehandle		GET_DIR_DELEGATION and sets the current filehandle
	(see <xref target="using_secinfo"/>).		(see <xref target="using_secinfo" format="default"/>).
	</t>		</t>
	<t>		<t>
	The directory delegation covers all the entries in the		The directory delegation covers all the entries in the
	directory except the parent entry. That means if a directory and		directory except the parent entry. That means if a directory and
	its parent both hold directory delegations, any changes to the		its parent both hold directory delegations, any changes to the
	parent will not cause a notification to be sent for the child		parent will not cause a notification to be sent for the child
	even though the child's parent entry points to the parent		even though the child's parent entry points to the parent
	directory.		directory.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_GETDEVICEINFO" numbered="true" toc="default">
	$ -->		<name>Operation 47: GETDEVICEINFO - Get Device Information</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_GETDEVICEINFO_ARGUMENT" numbered="true
	<!-- Copyright (C) The Internet Society (2006) -->		">
	<section anchor="OP_GETDEVICEINFO" title="Operation 47: GETDEVICEINFO - Get Devi		<name>ARGUMENT</name>
	ce Information" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_GETDEVICEINFO_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct GETDEVICEINFO4args {		struct GETDEVICEINFO4args {
	deviceid4 gdia_device_id;		deviceid4 gdia_device_id;
	layouttype4 gdia_layout_type;		layouttype4 gdia_layout_type;
	count4 gdia_maxcount;		count4 gdia_maxcount;
	bitmap4 gdia_notify_types;		bitmap4 gdia_notify_types;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_GETDEVICEINFO_RESULT" numbered="true">
	</figure>		<name>RESULT</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_GETDEVICEINFO_RESULT" title="RESULT">
	<figure>
	<artwork>
	struct GETDEVICEINFO4resok {		struct GETDEVICEINFO4resok {
	device_addr4 gdir_device_addr;		device_addr4 gdir_device_addr;
	bitmap4 gdir_notification;		bitmap4 gdir_notification;
	};		};
	union GETDEVICEINFO4res switch (nfsstat4 gdir_status) {		union GETDEVICEINFO4res switch (nfsstat4 gdir_status) {
	case NFS4_OK:		case NFS4_OK:
	GETDEVICEINFO4resok gdir_resok4;		GETDEVICEINFO4resok gdir_resok4;
	case NFS4ERR_TOOSMALL:		case NFS4ERR_TOOSMALL:
	count4 gdir_mincount;		count4 gdir_mincount;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_GETDEVICEINFO_DESCRIPTION" numbered="t
	</figure>		rue">
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_GETDEVICEINFO_DESCRIPTION" title="DESCRIPTIO		<t>
	N">
	<t>
	The GETDEVICEINFO operation returns pNFS storage device address		The GETDEVICEINFO operation returns pNFS storage device address
	information for the specified device ID.		information for the specified device ID.
	The client identifies the device information to be returned by		The client identifies the device information to be returned by
	providing the gdia_device_id and gdia_layout_type that uniquely		providing the gdia_device_id and gdia_layout_type that uniquely
	identify the device. The client provides gdia_maxcount		identify the device. The client provides gdia_maxcount
	to limit the number of bytes for the result. This maximum size		to limit the number of bytes for the result. This maximum size
	represents all of the data being returned within the		represents all of the data being returned within the
	GETDEVICEINFO4resok structure and includes the XDR overhead.		GETDEVICEINFO4resok structure and includes the XDR overhead.
	The server may return less data. If the server is unable to		The server may return less data. If the server is unable to
	return any information within the gdia_maxcount limit, the error		return any information within the gdia_maxcount limit, the error
	NFS4ERR_TOOSMALL will be returned. However, if gdia_maxcount is		NFS4ERR_TOOSMALL will be returned. However, if gdia_maxcount is
	zero, NFS4ERR_TOOSMALL MUST NOT be returned.		zero, NFS4ERR_TOOSMALL <bcp14>MUST NOT</bcp14> be returned.
	</t>		</t>
	<t>		<t>
	The da_layout_type field of the gdir_device_addr returned		The da_layout_type field of the gdir_device_addr returned
	by the server MUST be equal to the gdia_layout_type specified		by the server <bcp14>MUST</bcp14> be equal to the gdia_layout_type specifi
	by the client. If it is not equal, the client SHOULD ignore		ed
			by the client. If it is not equal, the client <bcp14>SHOULD</bcp14> ignor
			e
	the response as invalid and behave as if the server returned		the response as invalid and behave as if the server returned
	an error, even if the client does have support for the		an error, even if the client does have support for the
	layout type returned.		layout type returned.
	</t>		</t>
	<t>		<t>
	The client also provides a notification bitmap,		The client also provides a notification bitmap,
	gdia_notify_types, for the device ID mapping		gdia_notify_types, for the device ID mapping
	notification for which it is interested in receiving;		notification for which it is interested in receiving;
	the server must support device ID notifications		the server must support device ID notifications
	for the notification request to have affect.		for the notification request to have affect.
	The notification mask is composed in the same		The notification mask is composed in the same
	manner as the bitmap for file attributes (<xref		manner as the bitmap for file attributes (<xref target="fattr4" format="de
	target="fattr4" />). The numbers of bit positions		fault"/>). The numbers of bit positions
	are listed in the notify_device_type4 enumeration type		are listed in the notify_device_type4 enumeration type
	(<xref target="OP_CB_NOTIFY_DEVICEID" />). Only		(<xref target="OP_CB_NOTIFY_DEVICEID" format="default"/>). Only
	two enumerated values of notify_device_type4 currently		two enumerated values of notify_device_type4 currently
	apply to GETDEVICEINFO:		apply to GETDEVICEINFO:
	NOTIFY_DEVICEID4_CHANGE		NOTIFY_DEVICEID4_CHANGE
	and NOTIFY_DEVICEID4_DELETE (see <xref		and NOTIFY_DEVICEID4_DELETE (see <xref target="OP_CB_NOTIFY_DEVICEID" form
	target="OP_CB_NOTIFY_DEVICEID" />).		at="default"/>).
	</t>		</t>
	<t>		<t>
	The notification bitmap applies only to the specified device ID.		The notification bitmap applies only to the specified device ID.
	If a client sends a GETDEVICEINFO operation on a deviceID multiple times,		If a client sends a GETDEVICEINFO operation on a deviceID multiple times,
	the last notification bitmap is used by the server for		the last notification bitmap is used by the server for
	subsequent notifications. If the bitmap is zero or empty,		subsequent notifications. If the bitmap is zero or empty,
	then the device ID's notifications are turned off.		then the device ID's notifications are turned off.
	</t>		</t>
	<t>		<t>
	If the client wants to just update or turn off notifications,		If the client wants to just update or turn off notifications,
	it MAY send a GETDEVICEINFO operation with gdia_maxcount set to zero.		it <bcp14>MAY</bcp14> send a GETDEVICEINFO operation with gdia_maxcount set to zero.
	In that event, if the device ID is valid, the reply's da_addr_body		In that event, if the device ID is valid, the reply's da_addr_body
	field of the gdir_device_addr field will be of zero length.		field of the gdir_device_addr field will be of zero length.
	</t>		</t>
	<t>		<t>
	If an unknown device ID is given in gdia_device_id,		If an unknown device ID is given in gdia_device_id,
	the server returns NFS4ERR_NOENT.		the server returns NFS4ERR_NOENT.
	Otherwise, the device address		Otherwise, the device address
	information is returned in gdir_device_addr.		information is returned in gdir_device_addr.
	Finally, if the server supports		Finally, if the server supports
	notifications for device ID mappings, the gdir_notification		notifications for device ID mappings, the gdir_notification
	result will contain a bitmap of which notifications		result will contain a bitmap of which notifications
	it will actually send to the client (via CB_NOTIFY_DEVICEID,		it will actually send to the client (via CB_NOTIFY_DEVICEID,
	see <xref target="OP_CB_NOTIFY_DEVICEID" />).		see <xref target="OP_CB_NOTIFY_DEVICEID" format="default"/>).
	</t>		</t>
	<t>		<t>
	If NFS4ERR_TOOSMALL is returned, the results also contain		If NFS4ERR_TOOSMALL is returned, the results also contain
	gdir_mincount. The value of gdir_mincount represents the		gdir_mincount. The value of gdir_mincount represents the
	minimum size necessary to obtain the device information.		minimum size necessary to obtain the device information.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_GETDEVICEINFO_IMPLEMENTATION" title="IMPLEME		<section toc="exclude" anchor="OP_GETDEVICEINFO_IMPLEMENTATION" numbered
	NTATION">		="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	Aside from updating or turning off notifications, another		Aside from updating or turning off notifications, another
	use case for gdia_maxcount being set to zero is to validate		use case for gdia_maxcount being set to zero is to validate
	a device ID.		a device ID.
	</t>		</t>
	<t>		<t>
	The client SHOULD request a notification for changes or		The client <bcp14>SHOULD</bcp14> request a notification for changes or
	deletion of a device ID to device address mapping so		deletion of a device ID to device address mapping so
	that the server can allow the client gracefully use a		that the server can allow the client gracefully use a
	new mapping, without having pending I/O fail abruptly,		new mapping, without having pending I/O fail abruptly,
	or force layouts using the device ID to be recalled		or force layouts using the device ID to be recalled
	or revoked.		or revoked.
	</t>		</t>
			<t>
	<t>
	It is possible that GETDEVICEINFO (and		It is possible that GETDEVICEINFO (and
	GETDEVICELIST) will race with CB_NOTIFY_DEVICEID,		GETDEVICELIST) will race with CB_NOTIFY_DEVICEID,
	i.e., CB_NOTIFY_DEVICEID arrives before the client		i.e., CB_NOTIFY_DEVICEID arrives before the client
	gets and processes the response to GETDEVICEINFO or		gets and processes the response to GETDEVICEINFO or
	GETDEVICELIST. The analysis of the race leverages the		GETDEVICELIST. The analysis of the race leverages the
	fact that the server MUST NOT delete a device ID that		fact that the server <bcp14>MUST NOT</bcp14> delete a device ID that
	is referred to by a layout the client has.		is referred to by a layout the client has.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	CB_NOTIFY_DEVICEID deletes a device ID.		CB_NOTIFY_DEVICEID deletes a device ID.
	If the client believes it has layouts that refer to the		If the client believes it has layouts that refer to the
	device ID, then it is possible that layouts referring to		device ID, then it is possible that layouts referring to
	the deleted device ID have been revoked.		the deleted device ID have been revoked.
	The client should send a TEST_STATEID request using the		The client should send a TEST_STATEID request using the
	stateid for each layout that might have been revoked. If		stateid for each layout that might have been revoked. If
	TEST_STATEID indicates that any layouts have been revoked, the		TEST_STATEID indicates that any layouts have been revoked, the
	client must recover from layout revocation as described in		client must recover from layout revocation as described in
	<xref		<xref target="revoke_layout" format="default"/>. If TEST_STATEID indicate
	target="revoke_layout" />. If TEST_STATEID indicates that at least		s that at least
	one layout has not been revoked, the client should send		one layout has not been revoked, the client should send
	a GETDEVICEINFO operation on the supposedly deleted		a GETDEVICEINFO operation on the supposedly deleted
	device ID to verify that the device ID		device ID to verify that the device ID
	has been deleted.		has been deleted.
	<vspace blankLines='1' />		</t>
			<t>
	If GETDEVICEINFO indicates that the device ID		If GETDEVICEINFO indicates that the device ID
	does not exist, then the client assumes the server is faulty		does not exist, then the client assumes the server is faulty
	and recovers by sending an EXCHANGE_ID operation. If GETDEVICEINFO		and recovers by sending an EXCHANGE_ID operation. If GETDEVICEINFO
	indicates that the device ID does exist, then while the server is		indicates that the device ID does exist, then while the server is
	faulty for sending an erroneous device ID deletion notification,		faulty for sending an erroneous device ID deletion notification,
	the degree to which it is faulty does not require the client to		the degree to which it is faulty does not require the client to
	create a new client ID.		create a new client ID.
	<vspace blankLines='1' />		</t>
			<t>
	If the client does not have layouts that refer to the		If the client does not have layouts that refer to the
	device ID, no harm is done.		device ID, no harm is done.
	The client should mark the device ID as deleted, and when		The client should mark the device ID as deleted, and when
	GETDEVICEINFO or GETDEVICELIST results are		GETDEVICEINFO or GETDEVICELIST results are
	received that indicate that the device ID has been		received that indicate that the device ID has been
	in fact deleted, the device ID should be removed from the		in fact deleted, the device ID should be removed from the
	client's cache.		client's cache.
	</t>		</t>
			</li>
	<t>		<li>
	CB_NOTIFY_DEVICEID indicates that a device ID's device		CB_NOTIFY_DEVICEID indicates that a device ID's device
	addressing mappings have changed. The client should assume		addressing mappings have changed. The client should assume
	that the results from the in-progress GETDEVICEINFO		that the results from the in-progress GETDEVICEINFO
	will be stale for the device ID		will be stale for the device ID
	once received, and so it should send another GETDEVICEINFO		once received, and so it should send another GETDEVICEINFO
	on the device ID.		on the device ID.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
			</section>
	</section>		<section anchor="OP_GETDEVICELIST" numbered="true" toc="default">
	</section>		<name>Operation 48: GETDEVICELIST - Get All Device Mappings for a File S
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		ystem</name>
	$ -->		<section toc="exclude" anchor="OP_GETDEVICELIST_ARGUMENT" numbered="true
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_GETDEVICELIST" title="Operation 48: GETDEVICELIST - Get All		<sourcecode type="xdr"><![CDATA[
	Device Mappings for a File System" >
	<section toc="exclude" anchor="OP_GETDEVICELIST_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct GETDEVICELIST4args {		struct GETDEVICELIST4args {
	/* CURRENT_FH: object belonging to the file system */		/* CURRENT_FH: object belonging to the file system */
	layouttype4 gdla_layout_type;		layouttype4 gdla_layout_type;
	/* number of deviceIDs to return */		/* number of deviceIDs to return */
	count4 gdla_maxdevices;		count4 gdla_maxdevices;
	nfs_cookie4 gdla_cookie;		nfs_cookie4 gdla_cookie;
	verifier4 gdla_cookieverf;		verifier4 gdla_cookieverf;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_GETDEVICELIST_RESULT" numbered="true">
	</figure>		<name>RESULT</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_GETDEVICELIST_RESULT" title="RESULT">
	<figure>
	<artwork>
	struct GETDEVICELIST4resok {		struct GETDEVICELIST4resok {
	nfs_cookie4 gdlr_cookie;		nfs_cookie4 gdlr_cookie;
	verifier4 gdlr_cookieverf;		verifier4 gdlr_cookieverf;
	deviceid4 gdlr_deviceid_list&lt;>;		deviceid4 gdlr_deviceid_list<>;
	bool gdlr_eof;		bool gdlr_eof;
	};		};
	union GETDEVICELIST4res switch (nfsstat4 gdlr_status) {		union GETDEVICELIST4res switch (nfsstat4 gdlr_status) {
	case NFS4_OK:		case NFS4_OK:
	GETDEVICELIST4resok gdlr_resok4;		GETDEVICELIST4resok gdlr_resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_GETDEVICELIST_DESCRIPTION" numbered="t
	</figure>		rue">
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_GETDEVICELIST_DESCRIPTION" title="DESCRIPTIO		<t>
	N">
	<t>
	This operation is used by the client to enumerate all of the		This operation is used by the client to enumerate all of the
	device IDs that a server's file system uses.		device IDs that a server's file system uses.
	</t>		</t>
	<t>		<t>
	The client provides a current filehandle of a file object that		The client provides a current filehandle of a file object that
	belongs to the file system (i.e., all file objects sharing the same		belongs to the file system (i.e., all file objects sharing the same
	fsid as that of the current filehandle) and the layout type		fsid as that of the current filehandle) and the layout type
	in gdia_layout_type. Since		in gdia_layout_type. Since
	this operation might require multiple calls to enumerate all the		this operation might require multiple calls to enumerate all the
	device IDs (and is thus		device IDs (and is thus
	similar to the <xref target="OP_READDIR">		similar to the <xref target="OP_READDIR" format="default">
	READDIR</xref> operation), the client also provides gdia_cookie		READDIR</xref> operation), the client also provides gdia_cookie
	and gdia_cookieverf to specify the current cursor position in the		and gdia_cookieverf to specify the current cursor position in the
	list. When the client wants to read from the beginning of the		list. When the client wants to read from the beginning of the
	file system's device mappings, it sets gdla_cookie to zero. The		file system's device mappings, it sets gdla_cookie to zero. The
	field gdla_cookieverf MUST be ignored by the server when		field gdla_cookieverf <bcp14>MUST</bcp14> be ignored by the server when
	gdla_cookie is zero.		gdla_cookie is zero.
	The client provides gdla_maxdevices to limit the number of device IDs		The client provides gdla_maxdevices to limit the number of device IDs
	in the result. If gdla_maxdevices is zero, the server MUST return		in the result. If gdla_maxdevices is zero, the server <bcp14>MUST</bcp14> return
	NFS4ERR_INVAL.		NFS4ERR_INVAL.
	The server MAY return fewer device IDs.		The server <bcp14>MAY</bcp14> return fewer device IDs.
	</t>		</t>
			<t>
	<t>
	The successful response to the operation will contain the		The successful response to the operation will contain the
	cookie, gdlr_cookie, and the cookie verifier, gdlr_cookieverf, to be		cookie, gdlr_cookie, and the cookie verifier, gdlr_cookieverf, to be
	used on the subsequent GETDEVICELIST. A gdlr_eof value of TRUE		used on the subsequent GETDEVICELIST. A gdlr_eof value of TRUE
	signifies that there are no remaining entries in the server's		signifies that there are no remaining entries in the server's
	device list. Each element of gdlr_deviceid_list contains		device list. Each element of gdlr_deviceid_list contains
	a device ID.		a device ID.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_GETDEVICELIST_IMPLEMENTATION" title="IMPLEME		<section toc="exclude" anchor="OP_GETDEVICELIST_IMPLEMENTATION" numbered
	NTATION">		="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	An example of the use of this operation is for pNFS		An example of the use of this operation is for pNFS
	clients and servers that use LAYOUT4_BLOCK_VOLUME		clients and servers that use LAYOUT4_BLOCK_VOLUME
	layouts. In these environments it may be helpful		layouts. In these environments it may be helpful
	for a client to determine device accessibility upon		for a client to determine device accessibility upon
	first file system access.		first file system access.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_LAYOUTCOMMIT" numbered="true" toc="default">
	$ -->		<name>Operation 49: LAYOUTCOMMIT - Commit Writes Made Using a Layout</na
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		me>
	<!-- Copyright (C) The Internet Society (2006) -->		<section toc="exclude" anchor="OP_LAYOUTCOMMIT_ARGUMENT" numbered="true"
	<section anchor="OP_LAYOUTCOMMIT" title="Operation 49: LAYOUTCOMMIT - Commit Wri		>
	tes Made Using a Layout" >		<name>ARGUMENT</name>
			<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_LAYOUTCOMMIT_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	union newtime4 switch (bool nt_timechanged) {		union newtime4 switch (bool nt_timechanged) {
	case TRUE:		case TRUE:
	nfstime4 nt_time;		nfstime4 nt_time;
	case FALSE:		case FALSE:
	void;		void;
	};		};
	union newoffset4 switch (bool no_newoffset) {		union newoffset4 switch (bool no_newoffset) {
	case TRUE:		case TRUE:
	offset4 no_offset;		offset4 no_offset;
	skipping to change at line 37796 ¶		skipping to change at line 37785 ¶
	struct LAYOUTCOMMIT4args {		struct LAYOUTCOMMIT4args {
	/* CURRENT_FH: file */		/* CURRENT_FH: file */
	offset4 loca_offset;		offset4 loca_offset;
	length4 loca_length;		length4 loca_length;
	bool loca_reclaim;		bool loca_reclaim;
	stateid4 loca_stateid;		stateid4 loca_stateid;
	newoffset4 loca_last_write_offset;		newoffset4 loca_last_write_offset;
	newtime4 loca_time_modify;		newtime4 loca_time_modify;
	layoutupdate4 loca_layoutupdate;		layoutupdate4 loca_layoutupdate;
	};		};]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_LAYOUTCOMMIT_RESULT" numbered="true">
	</section>		<name>RESULT</name>
	<section toc="exclude" anchor="OP_LAYOUTCOMMIT_RESULT" title="RESULT">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	union newsize4 switch (bool ns_sizechanged) {		union newsize4 switch (bool ns_sizechanged) {
	case TRUE:		case TRUE:
	length4 ns_size;		length4 ns_size;
	case FALSE:		case FALSE:
	void;		void;
	};		};
	struct LAYOUTCOMMIT4resok {		struct LAYOUTCOMMIT4resok {
	newsize4 locr_newsize;		newsize4 locr_newsize;
	};		};
	union LAYOUTCOMMIT4res switch (nfsstat4 locr_status) {		union LAYOUTCOMMIT4res switch (nfsstat4 locr_status) {
	case NFS4_OK:		case NFS4_OK:
	LAYOUTCOMMIT4resok locr_resok4;		LAYOUTCOMMIT4resok locr_resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LAYOUTCOMMIT_DESCRIPTION" numbered="tr
	</figure>		ue">
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_LAYOUTCOMMIT_DESCRIPTION" title="DESCRIPTION		<t>
	">
	<t>
	The LAYOUTCOMMIT operation commits changes in the layout represented by th e current		The LAYOUTCOMMIT operation commits changes in the layout represented by th e current
	filehandle, client ID (derived from the session ID in the		filehandle, client ID (derived from the session ID in the
	preceding SEQUENCE operation), byte-range, and stateid. Since		preceding SEQUENCE operation), byte-range, and stateid. Since
	layouts are sub-dividable, a smaller portion of a layout,		layouts are sub-dividable, a smaller portion of a layout,
	retrieved via LAYOUTGET, can be committed. The byte-range being		retrieved via LAYOUTGET, can be committed. The byte-range being
	committed is specified through the byte-range (loca_offset and		committed is specified through the byte-range (loca_offset and
	loca_length). This byte-range MUST overlap with one or more existing layou		loca_length). This byte-range <bcp14>MUST</bcp14> overlap with one or more
	ts		existing layouts
	previously granted via LAYOUTGET (<xref target="OP_LAYOUTGET"/>),		previously granted via LAYOUTGET (<xref target="OP_LAYOUTGET" format="defa
			ult"/>),
	each with an iomode of LAYOUTIOMODE4_RW. In the		each with an iomode of LAYOUTIOMODE4_RW. In the
	case where the iomode of any held layout segment is not		case where the iomode of any held layout segment is not
	LAYOUTIOMODE4_RW, the server should return the error		LAYOUTIOMODE4_RW, the server should return the error
	NFS4ERR_BAD_IOMODE. For the case where the client		NFS4ERR_BAD_IOMODE. For the case where the client
	does not hold matching layout segment(s) for the		does not hold matching layout segment(s) for the
	defined byte-range, the server should return the error		defined byte-range, the server should return the error
	NFS4ERR_BAD_LAYOUT.		NFS4ERR_BAD_LAYOUT.
	</t>		</t>
	<t>		<t>
	The LAYOUTCOMMIT operation indicates that the client has		The LAYOUTCOMMIT operation indicates that the client has
	completed writes using a layout obtained by a previous		completed writes using a layout obtained by a previous
	LAYOUTGET. The client may have only written a subset of the		LAYOUTGET. The client may have only written a subset of the
	data range it previously requested. LAYOUTCOMMIT allows it to		data range it previously requested. LAYOUTCOMMIT allows it to
	commit or discard provisionally allocated space and to update		commit or discard provisionally allocated space and to update
	the server with a new end-of-file. The layout referenced by		the server with a new end-of-file. The layout referenced by
	LAYOUTCOMMIT is still valid after the operation completes and		LAYOUTCOMMIT is still valid after the operation completes and
	can be continued to be referenced by the client ID, filehandle,		can be continued to be referenced by the client ID, filehandle,
	byte-range, layout type, and stateid.		byte-range, layout type, and stateid.
	</t>		</t>
	<t>		<t>
	If the loca_reclaim field is set to TRUE, this indicates that		If the loca_reclaim field is set to TRUE, this indicates that
	the client is attempting to commit changes to a layout after the		the client is attempting to commit changes to a layout after the
	restart of the metadata server during the metadata server's		restart of the metadata server during the metadata server's
	recovery grace period (see <xref target="mds_recovery"/>). This type of r equest may be necessary		recovery grace period (see <xref target="mds_recovery" format="default"/>) . This type of request may be necessary
	when the client has uncommitted writes to provisionally		when the client has uncommitted writes to provisionally
	allocated byte-ranges of a file that were sent to the storage		allocated byte-ranges of a file that were sent to the storage
	devices before the restart of the metadata server. In this case,		devices before the restart of the metadata server. In this case,
	the layout provided by the client MUST be a subset of a writable		the layout provided by the client <bcp14>MUST</bcp14> be a subset of a wri table
	layout that the client held immediately before the restart of the		layout that the client held immediately before the restart of the
	metadata server. The value of the field loca_stateid MUST		metadata server. The value of the field loca_stateid <bcp14>MUST</bcp14>
	be a value that the metadata server returned before it restarted.		be a value that the metadata server returned before it restarted.
	The metadata server is free to accept or		The metadata server is free to accept or
	reject this request based on its own internal metadata		reject this request based on its own internal metadata
	consistency checks. If the metadata server finds that the		consistency checks. If the metadata server finds that the
	layout provided by the client does not pass its consistency		layout provided by the client does not pass its consistency
	checks, it MUST reject the request with the status		checks, it <bcp14>MUST</bcp14> reject the request with the status
	NFS4ERR_RECLAIM_BAD. The successful completion of the		NFS4ERR_RECLAIM_BAD. The successful completion of the
	LAYOUTCOMMIT request with loca_reclaim set to TRUE does NOT		LAYOUTCOMMIT request with loca_reclaim set to TRUE does NOT
	provide the client with a layout for the file. It simply		provide the client with a layout for the file. It simply
	commits the changes to the layout specified in the		commits the changes to the layout specified in the
	loca_layoutupdate field. To obtain a layout for the file, the		loca_layoutupdate field. To obtain a layout for the file, the
	client must send a LAYOUTGET request to the server after the		client must send a LAYOUTGET request to the server after the
	server's grace period has expired. If the metadata server		server's grace period has expired. If the metadata server
	receives a LAYOUTCOMMIT request with loca_reclaim set to TRUE		receives a LAYOUTCOMMIT request with loca_reclaim set to TRUE
	when the metadata server is not in its recovery grace period, it		when the metadata server is not in its recovery grace period, it
	MUST reject the request with the status NFS4ERR_NO_GRACE.		<bcp14>MUST</bcp14> reject the request with the status NFS4ERR_NO_GRACE.
	</t>		</t>
	<t>		<t>
	Setting the loca_reclaim field to TRUE is required if and only		Setting the loca_reclaim field to TRUE is required if and only
	if the committed layout was acquired before the metadata server		if the committed layout was acquired before the metadata server
	restart. If the client is committing a layout that was acquired		restart. If the client is committing a layout that was acquired
	during the metadata server's grace period, it MUST set the		during the metadata server's grace period, it <bcp14>MUST</bcp14> set the
	"reclaim" field to FALSE.		"reclaim" field to FALSE.
	</t>		</t>
	<t>		<t>
	The loca_stateid is a layout stateid value as		The loca_stateid is a layout stateid value as
	returned by previously successful layout operations		returned by previously successful layout operations
	(see <xref target="layout_stateid"/>).		(see <xref target="layout_stateid" format="default"/>).
	</t>		</t>
	<t>		<t>
	The loca_last_write_offset field specifies the offset of the		The loca_last_write_offset field specifies the offset of the
	last byte written by the client previous to the LAYOUTCOMMIT.		last byte written by the client previous to the LAYOUTCOMMIT.
	Note that this value is never equal to the file's size (at most		Note that this value is never equal to the file's size (at most
	it is one byte less than the file's size) and MUST be less than		it is one byte less than the file's size) and <bcp14>MUST</bcp14> be less
	or equal to NFS4_MAXFILEOFF. Also, loca_last_write_offset MUST		than
			or equal to NFS4_MAXFILEOFF. Also, loca_last_write_offset <bcp14>MUST</bc
			p14>
	overlap the range described by loca_offset and loca_length.		overlap the range described by loca_offset and loca_length.
	The metadata server		The metadata server
	may use this information to determine whether the file's size		may use this information to determine whether the file's size
	needs to be updated. If the metadata server updates the file's		needs to be updated. If the metadata server updates the file's
	size as the result of the LAYOUTCOMMIT operation, it must return		size as the result of the LAYOUTCOMMIT operation, it must return
	the new size (locr_newsize.ns_size) as part of the results.		the new size (locr_newsize.ns_size) as part of the results.
	</t>		</t>
	<t>		<t>
	The loca_time_modify field		The loca_time_modify field
	allows the client to suggest a modification time it would like the metadat a		allows the client to suggest a modification time it would like the metadat a
	server to set. The metadata server may use the suggestion or		server to set. The metadata server may use the suggestion or
	it may use the time of the LAYOUTCOMMIT operation to set the modification		it may use the time of the LAYOUTCOMMIT operation to set the modification
	time. If the metadata server uses the client-provided		time. If the metadata server uses the client-provided
	modification time, it should ensure that time does not flow backwards. If the		modification time, it should ensure that time does not flow backwards. If the
	client wants to force the metadata server to set an exact time,		client wants to force the metadata server to set an exact time,
	the client should use a SETATTR operation in a COMPOUND right		the client should use a SETATTR operation in a COMPOUND right
	after LAYOUTCOMMIT. See <xref target="committing_layout" /> for		after LAYOUTCOMMIT. See <xref target="committing_layout" format="default" /> for
	more details. If the client desires the resultant modification time,		more details. If the client desires the resultant modification time,
	it should construct the COMPOUND so that a GETATTR		it should construct the COMPOUND so that a GETATTR
	follows the LAYOUTCOMMIT.		follows the LAYOUTCOMMIT.
	</t>		</t>
	<t>		<t>
	The loca_layoutupdate argument to LAYOUTCOMMIT provides a mechanism		The loca_layoutupdate argument to LAYOUTCOMMIT provides a mechanism
	for a client to provide layout-specific updates to the metadata		for a client to provide layout-specific updates to the metadata
	server. For example, the layout update can describe what byte-ranges		server. For example, the layout update can describe what byte-ranges
	of the original layout have been used and what byte-ranges can be		of the original layout have been used and what byte-ranges can be
	deallocated. There is no NFSv4.1 file layout-specific layoutupdate4		deallocated. There is no NFSv4.1 file layout-specific layoutupdate4
	structure.		structure.
	</t>		</t>
	<t>		<t>
	The layout information is more verbose for block devices than for		The layout information is more verbose for block devices than for
	objects and files because the latter two hide the details of block		objects and files because the latter two hide the details of block
	allocation behind their storage protocols. At the minimum, the		allocation behind their storage protocols. At the minimum, the
	client needs to communicate changes to the end-of-file location back		client needs to communicate changes to the end-of-file location back
	to the server, and, if desired, its view of the file's modification		to the server, and, if desired, its view of the file's modification
	time. For block/volume layouts, it needs to specify precisely		time. For block/volume layouts, it needs to specify precisely
	which blocks have been used.		which blocks have been used.
	</t>		</t>
	<t>		<t>
	If the layout identified in the arguments does not exist, the		If the layout identified in the arguments does not exist, the
	error NFS4ERR_BADLAYOUT is returned. The layout being committed		error NFS4ERR_BADLAYOUT is returned. The layout being committed
	may also be rejected if it does not correspond to an existing		may also be rejected if it does not correspond to an existing
	layout with an iomode of LAYOUTIOMODE4_RW.		layout with an iomode of LAYOUTIOMODE4_RW.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value and the		On success, the current filehandle retains its value and the
	current stateid retains its value.		current stateid retains its value.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_LAYOUTCOMMIT_IMPLEMENTATION" title="IMPLEMEN		<section toc="exclude" anchor="OP_LAYOUTCOMMIT_IMPLEMENTATION" numbered=
	TATION">		"true">
	<t>		<name>IMPLEMENTATION</name>
	The client MAY also use LAYOUTCOMMIT with the		<t>
			The client <bcp14>MAY</bcp14> also use LAYOUTCOMMIT with the
	loca_reclaim field set to TRUE to convey hints to modified file		loca_reclaim field set to TRUE to convey hints to modified file
	attributes or to report layout-type specific information such as		attributes or to report layout-type specific information such as
	I/O errors for object-based storage layouts, as normally done		I/O errors for object-based storage layouts, as normally done
	during normal operation. Doing so may help the metadata server		during normal operation. Doing so may help the metadata server
	to recover files more efficiently after restart. For example,		to recover files more efficiently after restart. For example,
	some file system implementations may require expansive recovery		some file system implementations may require expansive recovery
	of file system objects if the metadata server does not get a		of file system objects if the metadata server does not get a
	positive indication from all clients holding a LAYOUTIOMODE4_RW layout tha t		positive indication from all clients holding a LAYOUTIOMODE4_RW layout tha t
	they have successfully completed all their writes. Sending a		they have successfully completed all their writes. Sending a
	LAYOUTCOMMIT (if required) and then following with LAYOUTRETURN		LAYOUTCOMMIT (if required) and then following with LAYOUTRETURN
	can provide such an indication and allow for graceful and		can provide such an indication and allow for graceful and
	efficient recovery.		efficient recovery.
	</t>		</t>
	<t>		<t>
	If loca_reclaim is TRUE, the metadata server is free to		If loca_reclaim is TRUE, the metadata server is free to
	either examine or ignore the value in the field loca_stateid.		either examine or ignore the value in the field loca_stateid.
	The metadata server implementation might or might not		The metadata server implementation might or might not
	encode in its layout		encode in its layout
	stateid information that allows the metadate server to		stateid information that allows the metadata server to
	perform a consistency check on the LAYOUTCOMMIT request.		perform a consistency check on the LAYOUTCOMMIT request.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_LAYOUTGET" numbered="true" toc="default">
	$ -->		<name>Operation 50: LAYOUTGET - Get Layout Information</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_LAYOUTGET_ARGUMENT" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_LAYOUTGET" title="Operation 50: LAYOUTGET - Get Layout Infor		<sourcecode type="xdr"><![CDATA[
	mation" >
	<section toc="exclude" anchor="OP_LAYOUTGET_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct LAYOUTGET4args {		struct LAYOUTGET4args {
	/* CURRENT_FH: file */		/* CURRENT_FH: file */
	bool loga_signal_layout_avail;		bool loga_signal_layout_avail;
	layouttype4 loga_layout_type;		layouttype4 loga_layout_type;
	layoutiomode4 loga_iomode;		layoutiomode4 loga_iomode;
	offset4 loga_offset;		offset4 loga_offset;
	length4 loga_length;		length4 loga_length;
	length4 loga_minlength;		length4 loga_minlength;
	stateid4 loga_stateid;		stateid4 loga_stateid;
	count4 loga_maxcount;		count4 loga_maxcount;
	};		};]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_LAYOUTGET_RESULT" numbered="true">
	</section>		<name>RESULT</name>
	<section toc="exclude" anchor="OP_LAYOUTGET_RESULT" title="RESULT">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct LAYOUTGET4resok {		struct LAYOUTGET4resok {
	bool logr_return_on_close;		bool logr_return_on_close;
	stateid4 logr_stateid;		stateid4 logr_stateid;
	layout4 logr_layout&lt;>;		layout4 logr_layout<>;
	};		};
	union LAYOUTGET4res switch (nfsstat4 logr_status) {		union LAYOUTGET4res switch (nfsstat4 logr_status) {
	case NFS4_OK:		case NFS4_OK:
	LAYOUTGET4resok logr_resok4;		LAYOUTGET4resok logr_resok4;
	case NFS4ERR_LAYOUTTRYLATER:		case NFS4ERR_LAYOUTTRYLATER:
	bool logr_will_signal_layout_avail;		bool logr_will_signal_layout_avail;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LAYOUTGET_DESCRIPTION" numbered="true"
	</figure>		>
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_LAYOUTGET_DESCRIPTION" title="DESCRIPTION">		<t>
	<t>
	The LAYOUTGET operation requests a layout from the metadata server for rea ding or		The LAYOUTGET operation requests a layout from the metadata server for rea ding or
	writing the file given by the filehandle at the		writing the file given by the filehandle at the
	byte-range specified by offset and length. Layouts are		byte-range specified by offset and length. Layouts are
	identified by the client ID (derived from the session ID in the		identified by the client ID (derived from the session ID in the
	preceding SEQUENCE operation), current filehandle, layout type		preceding SEQUENCE operation), current filehandle, layout type
	(loga_layout_type), and the layout stateid (loga_stateid). The		(loga_layout_type), and the layout stateid (loga_stateid). The
	use of the loga_iomode field depends upon the layout type, but should		use of the loga_iomode field depends upon the layout type, but should
	reflect the client's data access intent.		reflect the client's data access intent.
	</t>		</t>
	<t>		<t>
	If the metadata server is in a grace period, and does not		If the metadata server is in a grace period, and does not
	persist layouts and device ID to device address mappings, then		persist layouts and device ID to device address mappings, then
	it MUST return NFS4ERR_GRACE (see <xref target="reclaim_locks"/>).		it <bcp14>MUST</bcp14> return NFS4ERR_GRACE (see <xref target="reclaim_loc
	</t>		ks" format="default"/>).
			</t>
	<t>		<t>
	The LAYOUTGET operation returns layout information		The LAYOUTGET operation returns layout information
	for the specified byte-range: a layout.		for the specified byte-range: a layout.
	The client actually specifies two ranges, both starting		The client actually specifies two ranges, both starting
	at the offset in the loga_offset field. The first		at the offset in the loga_offset field. The first
	range is between loga_offset and loga_offset + loga_length - 1		range is between loga_offset and loga_offset + loga_length - 1
	inclusive. This range indicates the desired range the client		inclusive. This range indicates the desired range the client
	wants the layout to cover. The second range is between		wants the layout to cover. The second range is between
	loga_offset and loga_offset + loga_minlength - 1 inclusive. This		loga_offset and loga_offset + loga_minlength - 1 inclusive. This
	range indicates the required range the client needs the layout		range indicates the required range the client needs the layout
	to cover. Thus, loga_minlength MUST be less than or equal to		to cover. Thus, loga_minlength <bcp14>MUST</bcp14> be less than or equal t o
	loga_length.		loga_length.
	</t>		</t>
			<t>
	<t>
	When a length field is set to NFS4_UINT64_MAX,		When a length field is set to NFS4_UINT64_MAX,
	this indicates a desire (when loga_length is NFS4_UINT64_MAX)		this indicates a desire (when loga_length is NFS4_UINT64_MAX)
	or requirement (when loga_minlength is NFS4_UINT64_MAX)		or requirement (when loga_minlength is NFS4_UINT64_MAX)
	to get a layout from loga_offset through the		to get a layout from loga_offset through the
	end-of-file, regardless of the file's length.		end-of-file, regardless of the file's length.
	</t>		</t>
	<t>		<t>
	The following rules govern the relationships among,		The following rules govern the relationships among,
	and the minima of,		and the minima of,
	loga_length, loga_minlength, and loga_offset.		loga_length, loga_minlength, and loga_offset.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	If loga_length is less than loga_minlength, the metadata server		If loga_length is less than loga_minlength, the metadata server
	MUST return NFS4ERR_INVAL.		<bcp14>MUST</bcp14> return NFS4ERR_INVAL.
	</t>		</li>
	<t>		<li>
	If loga_minlength is zero, this is an indication		If loga_minlength is zero, this is an indication
	to the metadata server that the client desires any layout		to the metadata server that the client desires any layout
	at offset loga_offset or less that the metadata server has		at offset loga_offset or less that the metadata server has
	"readily available". Readily is subjective, and depends on		"readily available". Readily is subjective, and depends on
	the layout type and the pNFS server implementation. For example,		the layout type and the pNFS server implementation. For example,
	some metadata servers might have to pre-allocate stable		some metadata servers might have to pre-allocate stable
	storage when they receive a request for a range of a		storage when they receive a request for a range of a
	file that goes beyond the file's current length.		file that goes beyond the file's current length.
	If loga_minlength is zero and		If loga_minlength is zero and
	loga_length is greater than zero, this tells the		loga_length is greater than zero, this tells the
	metadata server what range of the layout the client would		metadata server what range of the layout the client would
	prefer to have. If loga_length and loga_minlength		prefer to have. If loga_length and loga_minlength
	are both zero, then the client is indicating that it desires		are both zero, then the client is indicating that it desires
	a layout of any length with the ending offset of the range		a layout of any length with the ending offset of the range
	no less than the value specified loga_offset, and the starting offset at or		no less than the value specified loga_offset, and the starting offset at or
	below loga_offset. If the metadata server does not have		below loga_offset. If the metadata server does not have
	a layout that is readily available, then it MUST return		a layout that is readily available, then it <bcp14>MUST</bcp14> return
	NFS4ERR_LAYOUTTRYLATER.		NFS4ERR_LAYOUTTRYLATER.
	</t>		</li>
	<t>		<li>
	If the sum of loga_offset and loga_minlength exceeds		If the sum of loga_offset and loga_minlength exceeds
	NFS4_UINT64_MAX, and loga_minlength is not NFS4_UINT64_MAX,		NFS4_UINT64_MAX, and loga_minlength is not NFS4_UINT64_MAX,
	the error NFS4ERR_INVAL MUST result.		the error NFS4ERR_INVAL <bcp14>MUST</bcp14> result.
	</t>		</li>
	<t>		<li>
	If the sum of loga_offset and loga_length exceeds		If the sum of loga_offset and loga_length exceeds
	NFS4_UINT64_MAX, and loga_length is not NFS4_UINT64_MAX,		NFS4_UINT64_MAX, and loga_length is not NFS4_UINT64_MAX,
	the error NFS4ERR_INVAL MUST result.		the error NFS4ERR_INVAL <bcp14>MUST</bcp14> result.
	</t>		</li>
	</list>		</ul>
			<t>
	After the metadata server has performed the above checks on loga_offset,		After the metadata server has performed the above checks on loga_offset,
	loga_minlength, and loga_offset, the metadata server MUST return a		loga_minlength, and loga_offset, the metadata server <bcp14>MUST</bcp14> r
	layout according to the rules in <xref target="layout_hell"/>.		eturn a
	</t>		layout according to the rules in <xref target="layout_hell" format="defaul
	<texttable anchor='layout_hell'>		t"/>.
			</t>
	<preamble>		<t>
	Acceptable layouts based on loga_minlength.		Acceptable layouts based on loga_minlength.
	Note: u64m = NFS4_UINT64_MAX; a_off = loga_offset;		Note: u64m = NFS4_UINT64_MAX; a_off = loga_offset;
	a_minlen = loga_minlength.		a_minlen = loga_minlength.
	</preamble>		</t>
			<table anchor="layout_hell" align="center">
	<ttcol>Layout iomode of request</ttcol>		<thead>
	<ttcol>Layout a_minlen of request</ttcol>		<tr>
	<ttcol>Layout iomode of reply</ttcol>		<th align="left">Layout iomode of request</th>
	<ttcol>Layout offset of reply</ttcol>		<th align="left">Layout a_minlen of request</th>
	<ttcol>Layout length of reply</ttcol>		<th align="left">Layout iomode of reply</th>
			<th align="left">Layout offset of reply</th>
	<c>_READ</c>		<th align="left">Layout length of reply</th>
	<c>u64m</c>		</tr>
	<c>MAY be _READ</c>		</thead>
	<c>MUST be &lt;= a_off</c>		<tbody>
	<c>MUST be >= file length - layout offset</c>		<tr>
			<td align="left">_READ</td>
	<c>_READ</c>		<td align="left">u64m</td>
	<c>u64m</c>		<td align="left"><bcp14>MAY</bcp14> be _READ</td>
	<c>MAY be _RW</c>		<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
	<c>MUST be &lt;= a_off</c>		<td align="left"><bcp14>MUST</bcp14> be &gt;= file length - layo
	<c>MUST be u64m</c>		ut offset</td>
			</tr>
	<c>_READ</c>		<tr>
	<c>> 0 and &lt; u64m</c>		<td align="left">_READ</td>
	<c>MAY be _READ</c>		<td align="left">u64m</td>
	<c>MUST be &lt;= a_off</c>		<td align="left"><bcp14>MAY</bcp14> be _RW</td>
	<c>MUST be >= MIN(file length, a_minlen + a_off) - layout offset</c>		<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
			<td align="left"><bcp14>MUST</bcp14> be u64m</td>
	<c>_READ</c>		</tr>
	<c>> 0 and &lt; u64m</c>		<tr>
	<c>MAY be _RW</c>		<td align="left">_READ</td>
	<c>MUST be &lt;= a_off</c>		<td align="left">&gt; 0 and &lt; u64m</td>
	<c>MUST be >= a_off - layout offset + a_minlen</c>		<td align="left"><bcp14>MAY</bcp14> be _READ</td>
			<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
	<c>_READ</c>		<td align="left"><bcp14>MUST</bcp14> be &gt;= MIN(file length, a
	<c>0</c>		_minlen + a_off) - layout offset</td>
	<c>MAY be _READ</c>		</tr>
	<c>MUST be &lt;= a_off</c>		<tr>
	<c>MUST be > 0</c>		<td align="left">_READ</td>
			<td align="left">&gt; 0 and &lt; u64m</td>
	<c>_READ</c>		<td align="left"><bcp14>MAY</bcp14> be _RW</td>
	<c>0</c>		<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
	<c>MAY be _RW</c>		<td align="left"><bcp14>MUST</bcp14> be &gt;= a_off - layout off
	<c>MUST be &lt;= a_off</c>		set + a_minlen</td>
	<c>MUST be > 0</c>		</tr>
			<tr>
	<c>_RW</c>		<td align="left">_READ</td>
	<c>u64m</c>		<td align="left">0</td>
	<c>MUST be _RW</c>		<td align="left"><bcp14>MAY</bcp14> be _READ</td>
	<c>MUST be &lt;= a_off</c>		<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
	<c>MUST be u64m</c>		<td align="left"><bcp14>MUST</bcp14> be &gt; 0</td>
			</tr>
	<c>_RW</c>		<tr>
	<c>> 0 and &lt; u64m</c>		<td align="left">_READ</td>
	<c>MUST be _RW</c>		<td align="left">0</td>
	<c>MUST be &lt;= a_off</c>		<td align="left"><bcp14>MAY</bcp14> be _RW</td>
	<c>MUST be >= a_off - layout offset + a_minlen</c>		<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
			<td align="left"><bcp14>MUST</bcp14> be &gt; 0</td>
	<c>_RW</c>		</tr>
	<c>0</c>		<tr>
	<c>MUST be _RW</c>		<td align="left">_RW</td>
	<c>MUST be &lt;= a_off</c>		<td align="left">u64m</td>
	<c>MUST be > 0</c>		<td align="left"><bcp14>MUST</bcp14> be _RW</td>
			<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
	</texttable>		<td align="left"><bcp14>MUST</bcp14> be u64m</td>
	<t>		</tr>
			<tr>
			<td align="left">_RW</td>
			<td align="left">&gt; 0 and &lt; u64m</td>
			<td align="left"><bcp14>MUST</bcp14> be _RW</td>
			<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
			<td align="left"><bcp14>MUST</bcp14> be &gt;= a_off - layout off
			set + a_minlen</td>
			</tr>
			<tr>
			<td align="left">_RW</td>
			<td align="left">0</td>
			<td align="left"><bcp14>MUST</bcp14> be _RW</td>
			<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
			<td align="left"><bcp14>MUST</bcp14> be &gt; 0</td>
			</tr>
			</tbody>
			</table>
			<t>
	If loga_minlength is not zero and the metadata server cannot return a layou t according		If loga_minlength is not zero and the metadata server cannot return a layou t according
	to the rules in <xref target="layout_hell"/>,		to the rules in <xref target="layout_hell" format="default"/>,
	then the metadata server MUST return the error		then the metadata server <bcp14>MUST</bcp14> return the error
	NFS4ERR_BADLAYOUT. If loga_minlength is zero and the metadata server		NFS4ERR_BADLAYOUT. If loga_minlength is zero and the metadata server
	cannot or will not return a layout according		cannot or will not return a layout according
	to the rules in <xref target="layout_hell"/>,		to the rules in <xref target="layout_hell" format="default"/>,
	then the metadata server MUST return the error		then the metadata server <bcp14>MUST</bcp14> return the error
	NFS4ERR_LAYOUTTRYLATER.		NFS4ERR_LAYOUTTRYLATER.
	Assuming that loga_length is greater		Assuming that loga_length is greater
	than loga_minlength or equal to zero, the metadata server SHOULD		than loga_minlength or equal to zero, the metadata server <bcp14>SHOULD</bc
	return a layout according to the rules in <xref		p14>
	target="layout_hell2"/>.		return a layout according to the rules in <xref target="layout_hell2" forma
	</t>		t="default"/>.
			</t>
	<texttable anchor='layout_hell2'>		<t>
	<preamble>
	Desired layouts based on loga_length.		Desired layouts based on loga_length.
	The rules of <xref target='layout_hell'/> MUST be applied first.		The rules of <xref target="layout_hell" format="default"/> <bcp14>MUST</bc p14> be applied first.
	Note: u64m = NFS4_UINT64_MAX; a_off = loga_offset;		Note: u64m = NFS4_UINT64_MAX; a_off = loga_offset;
	a_len = loga_length.		a_len = loga_length.
	</preamble>		</t>
			<table anchor="layout_hell2" align="center">
	<ttcol>Layout iomode of request</ttcol>		<thead>
	<ttcol>Layout a_len of request</ttcol>		<tr>
	<ttcol>Layout iomode of reply</ttcol>		<th align="left">Layout iomode of request</th>
	<ttcol>Layout offset of reply</ttcol>		<th align="left">Layout a_len of request</th>
	<ttcol>Layout length of reply</ttcol>		<th align="left">Layout iomode of reply</th>
			<th align="left">Layout offset of reply</th>
	<c>_READ</c>		<th align="left">Layout length of reply</th>
	<c>u64m</c>		</tr>
	<c>MAY be _READ</c>		</thead>
	<c>MUST be &lt;= a_off</c>		<tbody>
	<c>SHOULD be u64m</c>		<tr>
			<td align="left">_READ</td>
	<c>_READ</c>		<td align="left">u64m</td>
	<c>u64m</c>		<td align="left"><bcp14>MAY</bcp14> be _READ</td>
	<c>MAY be _RW</c>		<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
	<c>MUST be &lt;= a_off</c>		<td align="left"><bcp14>SHOULD</bcp14> be u64m</td>
	<c>SHOULD be u64m</c>		</tr>
			<tr>
	<c>_READ</c>		<td align="left">_READ</td>
	<c>> 0 and &lt; u64m</c>		<td align="left">u64m</td>
	<c>MAY be _READ</c>		<td align="left"><bcp14>MAY</bcp14> be _RW</td>
	<c>MUST be &lt;= a_off</c>		<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
	<c>SHOULD be >= a_off - layout offset + a_len</c>		<td align="left"><bcp14>SHOULD</bcp14> be u64m</td>
			</tr>
	<c>_READ</c>		<tr>
	<c>> 0 and &lt; u64m</c>		<td align="left">_READ</td>
	<c>MAY be _RW</c>		<td align="left">&gt; 0 and &lt; u64m</td>
	<c>MUST be &lt;= a_off</c>		<td align="left"><bcp14>MAY</bcp14> be _READ</td>
	<c>SHOULD be >= a_off - layout offset + a_len</c>		<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
			<td align="left"><bcp14>SHOULD</bcp14> be &gt;= a_off - layout o
	<c>_READ</c>		ffset + a_len</td>
	<c>0</c>		</tr>
	<c>MAY be _READ</c>		<tr>
	<c>MUST be &lt;= a_off</c>		<td align="left">_READ</td>
	<c>SHOULD be > a_off - layout offset</c>		<td align="left">&gt; 0 and &lt; u64m</td>
			<td align="left"><bcp14>MAY</bcp14> be _RW</td>
	<c>_READ</c>		<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
	<c>0</c>		<td align="left"><bcp14>SHOULD</bcp14> be &gt;= a_off - layout o
	<c>MAY be _READ</c>		ffset + a_len</td>
	<c>MUST be &lt;= a_off</c>		</tr>
	<c>SHOULD be > a_off - layout offset</c>		<tr>
			<td align="left">_READ</td>
	<c>_RW</c>		<td align="left">0</td>
	<c>u64m</c>		<td align="left"><bcp14>MAY</bcp14> be _READ</td>
	<c>MUST be _RW</c>		<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
	<c>MUST be &lt;= a_off</c>		<td align="left"><bcp14>SHOULD</bcp14> be &gt; a_off - layout of
	<c>SHOULD be u64m</c>		fset</td>
			</tr>
	<c>_RW</c>		<tr>
	<c>> 0 and &lt; u64m</c>		<td align="left">_READ</td>
	<c>MUST be _RW</c>		<td align="left">0</td>
	<c>MUST be &lt;= a_off</c>		<td align="left"><bcp14>MAY</bcp14> be _READ</td>
	<c>SHOULD be >= a_off - layout offset + a_len</c>		<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
			<td align="left"><bcp14>SHOULD</bcp14> be &gt; a_off - layout of
	<c>_RW</c>		fset</td>
	<c>0</c>		</tr>
	<c>MUST be _RW</c>		<tr>
	<c>MUST be &lt;= a_off</c>		<td align="left">_RW</td>
	<c>SHOULD be > a_off - layout offset</c>		<td align="left">u64m</td>
	</texttable>		<td align="left"><bcp14>MUST</bcp14> be _RW</td>
			<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
	<t>		<td align="left"><bcp14>SHOULD</bcp14> be u64m</td>
			</tr>
			<tr>
			<td align="left">_RW</td>
			<td align="left">&gt; 0 and &lt; u64m</td>
			<td align="left"><bcp14>MUST</bcp14> be _RW</td>
			<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
			<td align="left"><bcp14>SHOULD</bcp14> be &gt;= a_off - layout o
			ffset + a_len</td>
			</tr>
			<tr>
			<td align="left">_RW</td>
			<td align="left">0</td>
			<td align="left"><bcp14>MUST</bcp14> be _RW</td>
			<td align="left"><bcp14>MUST</bcp14> be &lt;= a_off</td>
			<td align="left"><bcp14>SHOULD</bcp14> be &gt; a_off - layout of
			fset</td>
			</tr>
			</tbody>
			</table>
			<t>
	The loga_stateid field specifies a valid stateid.		The loga_stateid field specifies a valid stateid.
	If a layout is not currently held by the client,		If a layout is not currently held by the client,
	the loga_stateid field represents a stateid		the loga_stateid field represents a stateid
	reflecting the correspondingly valid open,		reflecting the correspondingly valid open,
	byte-range lock, or delegation stateid. Once a		byte-range lock, or delegation stateid. Once a
	layout is held on the file by the client, the		layout is held on the file by the client, the
	loga_stateid field MUST be a stateid as returned from		loga_stateid field <bcp14>MUST</bcp14> be a stateid as returned from
	a previous LAYOUTGET or LAYOUTRETURN operation or		a previous LAYOUTGET or LAYOUTRETURN operation or
	provided by a CB_LAYOUTRECALL operation (see <xref		provided by a CB_LAYOUTRECALL operation (see <xref target="layout_stateid"
	target="layout_stateid"/>).		format="default"/>).
	</t>		</t>
	<t>		<t>
	The loga_maxcount field specifies the maximum layout size (in bytes)		The loga_maxcount field specifies the maximum layout size (in bytes)
	that the client can handle. If the size of the layout structure		that the client can handle. If the size of the layout structure
	exceeds the size specified by maxcount, the metadata server will		exceeds the size specified by maxcount, the metadata server will
	return the NFS4ERR_TOOSMALL error.		return the NFS4ERR_TOOSMALL error.
	</t>		</t>
	<t>		<t>
	The returned layout is expressed as an array,		The returned layout is expressed as an array,
	logr_layout, with each element of type layout4. If a		logr_layout, with each element of type layout4. If a
	file has a single striping pattern, then logr_layout		file has a single striping pattern, then logr_layout
	SHOULD contain just one entry. Otherwise, if the		<bcp14>SHOULD</bcp14> contain just one entry. Otherwise, if the
	requested range overlaps more than one striping		requested range overlaps more than one striping
	pattern, logr_layout will contain the required number		pattern, logr_layout will contain the required number
	of entries. The elements of logr_layout MUST be sorted		of entries. The elements of logr_layout <bcp14>MUST</bcp14> be sorted
	in ascending order of the value of the lo_offset field		in ascending order of the value of the lo_offset field
	of each element. There MUST be no gaps or overlaps		of each element. There <bcp14>MUST</bcp14> be no gaps or overlaps
	in the range between two successive elements of		in the range between two successive elements of
	logr_layout. The lo_iomode field in each element of		logr_layout. The lo_iomode field in each element of
	logr_layout MUST be the same.		logr_layout <bcp14>MUST</bcp14> be the same.
	</t>		</t>
			<t>
	<t>		<xref target="layout_hell" format="default"/>
	<xref target="layout_hell" />
	and		and
	<xref target="layout_hell2" />		<xref target="layout_hell2" format="default"/>
	both refer to a returned layout iomode, offset, and length.		both refer to a returned layout iomode, offset, and length.
	Because the returned layout is encoded in the logr_layout array,		Because the returned layout is encoded in the logr_layout array,
	more description is required.		more description is required.
	<list style='hanging'>		</t>
			<dl newline="false" spacing="normal">
	<t hangText='iomode'/>		<dt>iomode</dt>
	<t>		<dd>
	The value of the returned layout iomode listed in		The value of the returned layout iomode listed in
	<xref target="layout_hell" />		<xref target="layout_hell" format="default"/>
	and		and
	<xref target="layout_hell2" />		<xref target="layout_hell2" format="default"/>
	is equal to the value of the lo_iomode field in each		is equal to the value of the lo_iomode field in each
	element of logr_layout.		element of logr_layout.
	As shown in <xref target="layout_hell" />		As shown in <xref target="layout_hell" format="default"/>
	and <xref target="layout_hell2" />,		and <xref target="layout_hell2" format="default"/>,
	the metadata server MAY return a layout with an lo_iomode		the metadata server <bcp14>MAY</bcp14> return a layout with an lo_iomode
	different from the requested iomode (field loga_iomode of the request).		different from the requested iomode (field loga_iomode of the request).
	If it does so, it MUST		If it does so, it <bcp14>MUST</bcp14>
	ensure that the lo_iomode is more permissive than the		ensure that the lo_iomode is more permissive than the
	loga_iomode requested. For example, this behavior allows an		loga_iomode requested. For example, this behavior allows an
	implementation to upgrade LAYOUTIOMODE4_READ requests to LAYOUTIOMODE4_RW		implementation to upgrade LAYOUTIOMODE4_READ requests to LAYOUTIOMODE4_RW
	requests at its discretion, within the limits of the layout type		requests at its discretion, within the limits of the layout type
	specific protocol. A lo_iomode of either LAYOUTIOMODE4_READ or		specific protocol. A lo_iomode of either LAYOUTIOMODE4_READ or
	LAYOUTIOMODE4_RW MUST be returned.		LAYOUTIOMODE4_RW <bcp14>MUST</bcp14> be returned.
	</t>
	<t hangText='offset'/>		</dd>
	<t>		<dt>offset</dt>
			<dd>
	The value of the returned layout offset listed in		The value of the returned layout offset listed in
	<xref target="layout_hell" />		<xref target="layout_hell" format="default"/>
	and		and
	<xref target="layout_hell2" />		<xref target="layout_hell2" format="default"/>
	is always equal to the lo_offset field of the first		is always equal to the lo_offset field of the first
	element logr_layout.		element logr_layout.
	</t>		</dd>
			<dt>length</dt>
	<t hangText='length'/>		<dd>
	<t>		<t>
	When setting the value of the returned layout		When setting the value of the returned layout
	length, the situation is complicated by the		length, the situation is complicated by the
	possibility that the special layout length value		possibility that the special layout length value
	NFS4_UINT64_MAX is involved. For a logr_layout		NFS4_UINT64_MAX is involved. For a logr_layout
	array of N elements, the lo_length field in the		array of N elements, the lo_length field in the
	first N-1 elements MUST NOT be NFS4_UINT64_MAX. The		first N-1 elements <bcp14>MUST NOT</bcp14> be NFS4_UINT64_MAX. The
	lo_length field of the last element of logr_layout		lo_length field of the last element of logr_layout
	can be NFS4_UINT64_MAX under some conditions as		can be NFS4_UINT64_MAX under some conditions as
	described in the following list.		described in the following list.
	<list style='symbols'>		</t>
			<ul spacing="normal">
	<t>		<li>
	If an applicable rule of <xref target="layout_hell"/>		If an applicable rule of <xref target="layout_hell" format="default"/>
	states that the metadata server MUST return a layout of length		states that the metadata server <bcp14>MUST</bcp14> return a layout of le
			ngth
	NFS4_UINT64_MAX, then the lo_length field of the last		NFS4_UINT64_MAX, then the lo_length field of the last
	element of logr_layout MUST be NFS4_UINT64_MAX.		element of logr_layout <bcp14>MUST</bcp14> be NFS4_UINT64_MAX.
	</t>		</li>
	<t>		<li>
	If an applicable rule of <xref target="layout_hell"/>		If an applicable rule of <xref target="layout_hell" format="default"/>
	states that the metadata server MUST NOT return a layout of length		states that the metadata server <bcp14>MUST NOT</bcp14> return a layout o
			f length
	NFS4_UINT64_MAX, then the lo_length field of the last		NFS4_UINT64_MAX, then the lo_length field of the last
	element of logr_layout MUST NOT be NFS4_UINT64_MAX.		element of logr_layout <bcp14>MUST NOT</bcp14> be NFS4_UINT64_MAX.
	</t>		</li>
	<t>		<li>
	If an applicable rule of <xref target="layout_hell2"/>		If an applicable rule of <xref target="layout_hell2" format="default"/>
	states that the metadata server SHOULD return a layout of length		states that the metadata server <bcp14>SHOULD</bcp14> return a layout of
			length
	NFS4_UINT64_MAX, then the lo_length field of the last		NFS4_UINT64_MAX, then the lo_length field of the last
	element of logr_layout SHOULD be NFS4_UINT64_MAX.		element of logr_layout <bcp14>SHOULD</bcp14> be NFS4_UINT64_MAX.
	</t>		</li>
	<t>		<li>
	When the value of the returned layout length of		When the value of the returned layout length of
	<xref target="layout_hell" />		<xref target="layout_hell" format="default"/>
	and		and
	<xref target="layout_hell2" /> is not NFS4_UINT64_MAX, then		<xref target="layout_hell2" format="default"/> is not NFS4_UINT64_MAX, th en
	the returned layout length is equal to the sum of the		the returned layout length is equal to the sum of the
	lo_length fields of each element of logr_layout.		lo_length fields of each element of logr_layout.
	</t>		</li>
			</ul>
	</list>		</dd>
			</dl>
	</t>		<t>
	</list>
	</t>
	<t>
	The logr_return_on_close result field is a directive to return		The logr_return_on_close result field is a directive to return
	the layout before closing the file. When the metadata server sets this		the layout before closing the file. When the metadata server sets this
	return value to TRUE, it MUST be prepared to recall the layout		return value to TRUE, it <bcp14>MUST</bcp14> be prepared to recall the lay out
	in the case in which the client fails to return the layout before close.		in the case in which the client fails to return the layout before close.
	For the metadata server that knows a layout must be returned before a		For the metadata server that knows a layout must be returned before a
	close of the file, this return value can be used to communicate		close of the file, this return value can be used to communicate
	the desired behavior to the client and thus remove one extra		the desired behavior to the client and thus remove one extra
	step from the client's and metadata server's interaction.		step from the client's and metadata server's interaction.
	</t>		</t>
	<t>		<t>
	The logr_stateid stateid is returned to		The logr_stateid stateid is returned to
	the client for use in subsequent layout related operations. See Sections		the client for use in subsequent layout related operations. See Sections
	<xref target="stateid" format="counter" />, <xref target="layout_stateid"		<xref target="stateid" format="counter"/>, <xref target="layout_stateid" f
	format="counter" />, and		ormat="counter"/>, and
	<xref target="pnfs_operation_sequencing" format="counter" /> for a further		<xref target="pnfs_operation_sequencing" format="counter"/> for a further
	discussion and requirements.		discussion and requirements.
	</t>		</t>
	<t>		<t>
	The format of the returned layout (lo_content)		The format of the returned layout (lo_content)
	is specific to the layout type.		is specific to the layout type.
	The value of the layout type (lo_content.loc_type) for each of		The value of the layout type (lo_content.loc_type) for each of
	the elements of the array of layouts returned by the metadata server		the elements of the array of layouts returned by the metadata server
	(logr_layout) MUST be equal to the loga_layout_type specified		(logr_layout) <bcp14>MUST</bcp14> be equal to the loga_layout_type specifi
	by the client. If it is not equal, the client SHOULD ignore		ed
			by the client. If it is not equal, the client <bcp14>SHOULD</bcp14> ignor
			e
	the response as invalid and behave as if the metadata server returned		the response as invalid and behave as if the metadata server returned
	an error, even if the client does have support for the		an error, even if the client does have support for the
	layout type returned.		layout type returned.
	</t>		</t>
	<t>		<t>
	If neither the requested file nor its		If neither the requested file nor its
	containing file system support layouts, the metadata server MUST return		containing file system support layouts, the metadata server <bcp14>MUST</b cp14> return
	NFS4ERR_LAYOUTUNAVAILABLE. If the layout type is not supported,		NFS4ERR_LAYOUTUNAVAILABLE. If the layout type is not supported,
	the metadata server MUST return NFS4ERR_UNKNOWN_LAYOUTTYPE.		the metadata server <bcp14>MUST</bcp14> return NFS4ERR_UNKNOWN_LAYOUTTYPE.
	If layouts are supported but no layout matches the client		If layouts are supported but no layout matches the client
	provided layout identification, the metadata server MUST return		provided layout identification, the metadata server <bcp14>MUST</bcp14> re turn
	NFS4ERR_BADLAYOUT. If an invalid loga_iomode is specified, or a		NFS4ERR_BADLAYOUT. If an invalid loga_iomode is specified, or a
	loga_iomode of LAYOUTIOMODE4_ANY is specified, the metadata server MUST		loga_iomode of LAYOUTIOMODE4_ANY is specified, the metadata server <bcp14> MUST</bcp14>
	return NFS4ERR_BADIOMODE.		return NFS4ERR_BADIOMODE.
	</t>		</t>
	<t>		<t>
	If the layout for the file is unavailable due to transient		If the layout for the file is unavailable due to transient
	conditions, e.g., file sharing prohibits layouts, the metadata server MUST		conditions, e.g., file sharing prohibits layouts, the metadata server <bcp 14>MUST</bcp14>
	return NFS4ERR_LAYOUTTRYLATER.		return NFS4ERR_LAYOUTTRYLATER.
	</t>		</t>
	<t>		<t>
	If the layout request is rejected due to an overlapping layout		If the layout request is rejected due to an overlapping layout
	recall, the metadata server MUST return NFS4ERR_RECALLCONFLICT. See <xref		recall, the metadata server <bcp14>MUST</bcp14> return NFS4ERR_RECALLCONFL
	target="pnfs_operation_sequencing"/> for details.		ICT. See <xref target="pnfs_operation_sequencing" format="default"/> for detail
	</t>		s.
	<t>		</t>
			<t>
	If the layout conflicts with a mandatory byte-range lock held on the		If the layout conflicts with a mandatory byte-range lock held on the
	file, and if the storage devices have no method of enforcing		file, and if the storage devices have no method of enforcing
	mandatory locks, other than through the restriction of layouts, the		mandatory locks, other than through the restriction of layouts, the
	metadata server SHOULD return NFS4ERR_LOCKED.		metadata server <bcp14>SHOULD</bcp14> return NFS4ERR_LOCKED.
	</t>		</t>
	<t>		<t>
	If client sets loga_signal_layout_avail to TRUE, then it is		If client sets loga_signal_layout_avail to TRUE, then it is
	registering with the client a "want" for a layout in the event		registering with the client a "want" for a layout in the event
	the layout cannot be obtained due to resource exhaustion.		the layout cannot be obtained due to resource exhaustion.
	If the metadata server supports and will honor the "want",		If the metadata server supports and will honor the "want",
	the results will have logr_will_signal_layout_avail		the results will have logr_will_signal_layout_avail
	set to TRUE.		set to TRUE.
	If so, the client should expect a CB_RECALLABLE_OBJ_AVAIL		If so, the client should expect a CB_RECALLABLE_OBJ_AVAIL
	operation to indicate that a layout is available.		operation to indicate that a layout is available.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value and the		On success, the current filehandle retains its value and the
	current stateid is updated to match the value as returned in the		current stateid is updated to match the value as returned in the
	results.		results.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_LAYOUTGET_IMPLEMENTATION" title="IMPLEMENTAT		<section toc="exclude" anchor="OP_LAYOUTGET_IMPLEMENTATION" numbered="tr
	ION">		ue">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	Typically, LAYOUTGET will be called as part of a		Typically, LAYOUTGET will be called as part of a
	COMPOUND request after an OPEN operation and results		COMPOUND request after an OPEN operation and results
	in the client having location information for the		in the client having location information for the
	file. This requires that loga_stateid be set to the		file. This requires that loga_stateid be set to the
	special stateid that tells the metadata server to use the		special stateid that tells the metadata server to use the
	current stateid, which is set by OPEN (see <xref		current stateid, which is set by OPEN (see <xref target="current_stateid"
	target="current_stateid"/>). A client may also hold		format="default"/>). A client may also hold
	a layout across multiple OPENs. The client specifies		a layout across multiple OPENs. The client specifies
	a layout type that limits what kind of layout the		a layout type that limits what kind of layout the
	metadata server will return. This prevents metadata servers from		metadata server will return. This prevents metadata servers from
	granting layouts that are unusable by the client.		granting layouts that are unusable by the client.
	</t>		</t>
	<t>		<t>
	As indicated by <xref target="layout_hell" /> and		As indicated by <xref target="layout_hell" format="default"/> and
	<xref target="layout_hell2" />, the specification of		<xref target="layout_hell2" format="default"/>, the specification of
	LAYOUTGET allows a pNFS client and server considerable		LAYOUTGET allows a pNFS client and server considerable
	flexibility.		flexibility.
	A pNFS client can take several strategies for sending		A pNFS client can take several strategies for sending
	LAYOUTGET. Some examples are as follows.		LAYOUTGET. Some examples are as follows.
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	If LAYOUTGET is preceded by OPEN in the same		If LAYOUTGET is preceded by OPEN in the same
	COMPOUND request and the OPEN requests OPEN4_SHARE_ACCESS_READ access,		COMPOUND request and the OPEN requests OPEN4_SHARE_ACCESS_READ access,
	the client might opt to request a _READ layout		the client might opt to request a _READ layout
	with loga_offset set to zero, loga_minlength set to		with loga_offset set to zero, loga_minlength set to
	zero, and loga_length set to NFS4_UINT64_MAX. If		zero, and loga_length set to NFS4_UINT64_MAX. If
	the file has space allocated to it, that space is		the file has space allocated to it, that space is
	striped over one or more storage devices, and there		striped over one or more storage devices, and there
	is either no conflicting layout or the concept of		is either no conflicting layout or the concept of
	a conflicting layout does not apply to the pNFS		a conflicting layout does not apply to the pNFS
	server's layout type or implementation, then the		server's layout type or implementation, then the
	metadata server might return a layout with a starting offset		metadata server might return a layout with a starting offset
	of zero, and a length equal to the length of the		of zero, and a length equal to the length of the
	file, if not NFS4_UINT64_MAX. If the length of the		file, if not NFS4_UINT64_MAX. If the length of the
	file is not a multiple of the		file is not a multiple of the
	pNFS server's stripe		pNFS server's stripe
	width (see <xref target="file_layout_definitions"/>		width (see <xref target="file_layout_definitions" format="default"/>
	for a formal definition), the metadata server might round up		for a formal definition), the metadata server might round up
	the returned layout's length.		the returned layout's length.
	</t>		</li>
			<li>
	<t>
	If LAYOUTGET is preceded by OPEN in the same		If LAYOUTGET is preceded by OPEN in the same
	COMPOUND request, and the OPEN requests OPEN4_SHARE_ACCESS_WRITE access a nd does		COMPOUND request, and the OPEN requests OPEN4_SHARE_ACCESS_WRITE access a nd does
	not truncate the file, the client might		not truncate the file, the client might
	opt to request a _RW layout with loga_offset set		opt to request a _RW layout with loga_offset set
	to zero, loga_minlength set to zero, and loga_length		to zero, loga_minlength set to zero, and loga_length
	set to the file's current length (if known), or		set to the file's current length (if known), or
	NFS4_UINT64_MAX. As with the previous case, under		NFS4_UINT64_MAX. As with the previous case, under
	some conditions the metadata server might return a layout		some conditions the metadata server might return a layout
	that covers the entire length of the file or beyond.		that covers the entire length of the file or beyond.
	</t>		</li>
	<t>		<li>
	This strategy is as above, but the OPEN truncates the file. In this case,		This strategy is as above, but the OPEN truncates the file. In this case,
	the client might anticipate it will be writing to the		the client might anticipate it will be writing to the
	file from offset zero, and so loga_offset and loga_minlength		file from offset zero, and so loga_offset and loga_minlength
	are set to zero, and loga_length is set to the value of		are set to zero, and loga_length is set to the value of
	threshold4_write_iosize. The metadata server might return a layout		threshold4_write_iosize. The metadata server might return a layout
	from offset zero with a length at least as long as		from offset zero with a length at least as long as
	threshold4_write_iosize.		threshold4_write_iosize.
	</t>		</li>
	<t>		<li>
	A process on the client invokes a request to read		A process on the client invokes a request to read
	from offset 10000 for length 50000. The client		from offset 10000 for length 50000. The client
	is using buffered I/O, and has buffer sizes of		is using buffered I/O, and has buffer sizes of
	4096 bytes. The client intends to map the request		4096 bytes. The client intends to map the request
	of the process into a series of READ requests		of the process into a series of READ requests
	starting at offset 8192. The end offset needs to be higher		starting at offset 8192. The end offset needs to be higher
	than 10000 + 50000 = 60000, and the next offset that is		than 10000 + 50000 = 60000, and the next offset that is
	a multiple of 4096 is 61440. The difference between 61440 and		a multiple of 4096 is 61440. The difference between 61440 and
	that starting offset of the layout is 53248 (which is		that starting offset of the layout is 53248 (which is
	the product of 4096 and 15).		the product of 4096 and 15).
	skipping to change at line 38561 ¶		skipping to change at line 38554 ¶
	53248, and loga_length set to the file's length		53248, and loga_length set to the file's length
	(if known) minus 8192 or NFS4_UINT64_MAX (if the		(if known) minus 8192 or NFS4_UINT64_MAX (if the
	file's length is not known). Since this LAYOUTGET		file's length is not known). Since this LAYOUTGET
	request exceeds the metadata server's threshold, it grants		request exceeds the metadata server's threshold, it grants
	the layout, possibly with an initial offset of		the layout, possibly with an initial offset of
	zero, with an end offset of at least 8192 + 53248 -		zero, with an end offset of at least 8192 + 53248 -
	1 = 61439, but preferably a layout with an offset		1 = 61439, but preferably a layout with an offset
	aligned on the stripe width and a length that is		aligned on the stripe width and a length that is
	a multiple of the stripe width.		a multiple of the stripe width.
	</t>		</li>
			<li>
	<t>
	This strategy is as above, but the client is not using buffered I/O, and		This strategy is as above, but the client is not using buffered I/O, and
	instead all internal I/O requests are sent directly to		instead all internal I/O requests are sent directly to
	the server. The LAYOUTGET request has loga_offset equal to		the server. The LAYOUTGET request has loga_offset equal to
	10000 and loga_minlength set to 50000. The value of loga_length		10000 and loga_minlength set to 50000. The value of loga_length
	is set to the length of the file. The metadata server is free to		is set to the length of the file. The metadata server is free to
	return a layout that fully overlaps the requested range, with		return a layout that fully overlaps the requested range, with
	a starting offset and length aligned on the stripe width.		a starting offset and length aligned on the stripe width.
	</t>		</li>
			<li>
	<t>
	Again, a process on the client invokes a request		Again, a process on the client invokes a request
	to read from offset 10000 for length 50000 (i.e. a		to read from offset 10000 for length 50000 (i.e. a
	range with a starting offset of 10000 and an ending		range with a starting offset of 10000 and an ending
	offset of 69999), and		offset of 69999), and
	buffered I/O is in use. The client is expecting		buffered I/O is in use. The client is expecting
	that the server might not be able to return the		that the server might not be able to return the
	layout for the full I/O range.		layout for the full I/O range.
	The client intends to map the request of the		The client intends to map the request of the
	process into a series of thirteen READ requests starting at		process into a series of thirteen READ requests starting at
	skipping to change at line 38605 ¶		skipping to change at line 38596 ¶
	and loga_length set to 53248 or higher. The server		and loga_length set to 53248 or higher. The server
	will grant a layout possibly with an initial offset		will grant a layout possibly with an initial offset
	of zero, with an end offset of at least 8192 + 4096 -		of zero, with an end offset of at least 8192 + 4096 -
	1 = 12287, but preferably a layout with an offset		1 = 12287, but preferably a layout with an offset
	aligned on the stripe width and a length that is a		aligned on the stripe width and a length that is a
	multiple of the stripe width. This will allow the		multiple of the stripe width. This will allow the
	client to make forward progress, possibly		client to make forward progress, possibly
	sending more LAYOUTGET operations for the remainder		sending more LAYOUTGET operations for the remainder
	of the range.		of the range.
	</t>		</li>
			<li>
	<t>
	An NFS client detects a sequential read pattern,		An NFS client detects a sequential read pattern,
	and so sends a LAYOUTGET operation that goes well beyond any		and so sends a LAYOUTGET operation that goes well beyond any
	current or pending read requests to the server. The		current or pending read requests to the server. The
	server might likewise detect this pattern, and		server might likewise detect this pattern, and
	grant the LAYOUTGET request. Once the client		grant the LAYOUTGET request. Once the client
	reads from an offset of the file that represents		reads from an offset of the file that represents
	50% of the way through the range of the last layout		50% of the way through the range of the last layout
	it received, in order to avoid stalling I/O that would wait		it received, in order to avoid stalling I/O that would wait
	for a layout, the client sends more operations		for a layout, the client sends more operations
	from an offset of the file that represents 50%		from an offset of the file that represents 50%
	of the way through the last layout it received. The client		of the way through the last layout it received. The client
	continues to request layouts with byte-ranges that are		continues to request layouts with byte-ranges that are
	well in advance of the byte-ranges of		well in advance of the byte-ranges of
	recent and/or read requests of processes running on the client.		recent and/or read requests of processes running on the client.
	</t>		</li>
	<t>		<li>
	This strategy is as above, but the client fails to detect the		This strategy is as above, but the client fails to detect the
	pattern, but the server does. The next time the		pattern, but the server does. The next time the
	metadata server gets a LAYOUTGET, it returns a layout with		metadata server gets a LAYOUTGET, it returns a layout with
	a length that is well beyond loga_minlength.		a length that is well beyond loga_minlength.
	</t>		</li>
			<li>
	<t>
	A client is using buffered I/O, and has a long		A client is using buffered I/O, and has a long
	queue of write-behinds to process and also detects		queue of write-behinds to process and also detects
	a sequential write pattern. It sends a LAYOUTGET		a sequential write pattern. It sends a LAYOUTGET
	for a layout that spans the range of the queued		for a layout that spans the range of the queued
	write-behinds and well beyond, including ranges		write-behinds and well beyond, including ranges
	beyond the filer's current length. The client		beyond the filer's current length. The client
	continues to send LAYOUTGET operations once the write-behind		continues to send LAYOUTGET operations once the write-behind
	queue reaches 50% of the maximum queue length.		queue reaches 50% of the maximum queue length.
	</t>		</li>
			</ul>
	</list>		<t>
	</t>
	<t>
	Once the client has obtained a layout referring to a		Once the client has obtained a layout referring to a
	particular device ID, the metadata server MUST NOT		particular device ID, the metadata server <bcp14>MUST NOT</bcp14>
	delete the device ID until the layout is returned		delete the device ID until the layout is returned
	or revoked.		or revoked.
	</t>		</t>
	<t>		<t>
	CB_NOTIFY_DEVICEID can race with LAYOUTGET. One race		CB_NOTIFY_DEVICEID can race with LAYOUTGET. One race
	scenario is that LAYOUTGET returns a device ID for which the		scenario is that LAYOUTGET returns a device ID for which the
	client does not have device address mappings,		client does not have device address mappings,
	and the metadata server sends a CB_NOTIFY_DEVICEID		and the metadata server sends a CB_NOTIFY_DEVICEID
	to add the device ID to the client's awareness		to add the device ID to the client's awareness
	and meanwhile the client sends GETDEVICEINFO on		and meanwhile the client sends GETDEVICEINFO on
	the device ID. This scenario is discussed in		the device ID. This scenario is discussed in
	<xref target="OP_GETDEVICEINFO_IMPLEMENTATION"/>.		<xref target="OP_GETDEVICEINFO_IMPLEMENTATION" format="default"/>.
	Another scenario is that the CB_NOTIFY_DEVICEID		Another scenario is that the CB_NOTIFY_DEVICEID
	is processed by the client before it processes		is processed by the client before it processes
	the results from LAYOUTGET. The client will send		the results from LAYOUTGET. The client will send
	a GETDEVICEINFO on the device ID. If the results		a GETDEVICEINFO on the device ID. If the results
	from GETDEVICEINFO are received before the client		from GETDEVICEINFO are received before the client
	gets results from LAYOUTGET, then there is no		gets results from LAYOUTGET, then there is no
	longer a race. If the results from LAYOUTGET are		longer a race. If the results from LAYOUTGET are
	received before the results from GETDEVICEINFO, the		received before the results from GETDEVICEINFO, the
	client can either wait for results of GETDEVICEINFO		client can either wait for results of GETDEVICEINFO
	or send another one to get possibly more up-to-date		or send another one to get possibly more up-to-date
	device address mappings for the device ID.		device address mappings for the device ID.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_LAYOUTRETURN" numbered="true" toc="default">
	$ -->		<name>Operation 51: LAYOUTRETURN - Release Layout Information</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_LAYOUTRETURN_ARGUMENT" numbered="true"
	<!-- Copyright (C) The Internet Society (2006) -->		>
	<section anchor="OP_LAYOUTRETURN" title="Operation 51: LAYOUTRETURN - Release La		<name>ARGUMENT</name>
	yout Information" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_LAYOUTRETURN_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	/* Constants used for LAYOUTRETURN and CB_LAYOUTRECALL */		/* Constants used for LAYOUTRETURN and CB_LAYOUTRECALL */
	const LAYOUT4_RET_REC_FILE = 1;		const LAYOUT4_RET_REC_FILE = 1;
	const LAYOUT4_RET_REC_FSID = 2;		const LAYOUT4_RET_REC_FSID = 2;
	const LAYOUT4_RET_REC_ALL = 3;		const LAYOUT4_RET_REC_ALL = 3;
	enum layoutreturn_type4 {		enum layoutreturn_type4 {
	LAYOUTRETURN4_FILE = LAYOUT4_RET_REC_FILE,		LAYOUTRETURN4_FILE = LAYOUT4_RET_REC_FILE,
	LAYOUTRETURN4_FSID = LAYOUT4_RET_REC_FSID,		LAYOUTRETURN4_FSID = LAYOUT4_RET_REC_FSID,
	LAYOUTRETURN4_ALL = LAYOUT4_RET_REC_ALL		LAYOUTRETURN4_ALL = LAYOUT4_RET_REC_ALL
	};		};
	struct layoutreturn_file4 {		struct layoutreturn_file4 {
	offset4 lrf_offset;		offset4 lrf_offset;
	length4 lrf_length;		length4 lrf_length;
	stateid4 lrf_stateid;		stateid4 lrf_stateid;
	/* layouttype4 specific data */		/* layouttype4 specific data */
	opaque lrf_body&lt;>;		opaque lrf_body<>;
	};		};
	union layoutreturn4 switch(layoutreturn_type4 lr_returntype) {		union layoutreturn4 switch(layoutreturn_type4 lr_returntype) {
	case LAYOUTRETURN4_FILE:		case LAYOUTRETURN4_FILE:
	layoutreturn_file4 lr_layout;		layoutreturn_file4 lr_layout;
	default:		default:
	void;		void;
	};		};
	</artwork>
	</figure>
	<figure>
	<artwork>
	struct LAYOUTRETURN4args {		struct LAYOUTRETURN4args {
	/* CURRENT_FH: file */		/* CURRENT_FH: file */
	bool lora_reclaim;		bool lora_reclaim;
	layouttype4 lora_layout_type;		layouttype4 lora_layout_type;
	layoutiomode4 lora_iomode;		layoutiomode4 lora_iomode;
	layoutreturn4 lora_layoutreturn;		layoutreturn4 lora_layoutreturn;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LAYOUTRETURN_RESULT" numbered="true">
	</figure>		<name>RESULT</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_LAYOUTRETURN_RESULT" title="RESULT">
	<figure>
	<artwork>
	union layoutreturn_stateid switch (bool lrs_present) {		union layoutreturn_stateid switch (bool lrs_present) {
	case TRUE:		case TRUE:
	stateid4 lrs_stateid;		stateid4 lrs_stateid;
	case FALSE:		case FALSE:
	void;		void;
	};		};
	union LAYOUTRETURN4res switch (nfsstat4 lorr_status) {		union LAYOUTRETURN4res switch (nfsstat4 lorr_status) {
	case NFS4_OK:		case NFS4_OK:
	layoutreturn_stateid lorr_stateid;		layoutreturn_stateid lorr_stateid;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_LAYOUTRETURN_DESCRIPTION" numbered="tr
	</figure>		ue">
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_LAYOUTRETURN_DESCRIPTION" title="DESCRIPTION		<t>
	">
	<t>
	This operation returns from the client to the server		This operation returns from the client to the server
	one or more layouts represented by the client ID		one or more layouts represented by the client ID
	(derived from the session ID in the preceding SEQUENCE		(derived from the session ID in the preceding SEQUENCE
	operation), lora_layout_type, and lora_iomode.		operation), lora_layout_type, and lora_iomode.
	When lr_returntype is LAYOUTRETURN4_FILE, the		When lr_returntype is LAYOUTRETURN4_FILE, the
	returned layout is further identified by the current		returned layout is further identified by the current
	filehandle, lrf_offset, lrf_length, and lrf_stateid.		filehandle, lrf_offset, lrf_length, and lrf_stateid.
	If the lrf_length field is NFS4_UINT64_MAX, all bytes		If the lrf_length field is NFS4_UINT64_MAX, all bytes
	of the layout, starting at lrf_offset, are returned.		of the layout, starting at lrf_offset, are returned.
	When lr_returntype is LAYOUTRETURN4_FSID, the		When lr_returntype is LAYOUTRETURN4_FSID, the
	current filehandle is used to identify the file		current filehandle is used to identify the file
	system and all layouts matching the client ID,		system and all layouts matching the client ID,
	the fsid of the file system, lora_layout_type, and		the fsid of the file system, lora_layout_type, and
	lora_iomode are returned. When lr_returntype is		lora_iomode are returned. When lr_returntype is
	LAYOUTRETURN4_ALL, all layouts matching the client		LAYOUTRETURN4_ALL, all layouts matching the client
	ID, lora_layout_type, and lora_iomode are returned		ID, lora_layout_type, and lora_iomode are returned
	and the current filehandle is not used. After this		and the current filehandle is not used. After this
	call, the client MUST NOT use the returned layout(s)		call, the client <bcp14>MUST NOT</bcp14> use the returned layout(s)
	and the associated storage protocol to access the		and the associated storage protocol to access the
	file data.		file data.
	</t>		</t>
	<t>		<t>
	If the set of layouts designated in the case of		If the set of layouts designated in the case of
	LAYOUTRETURN4_FSID or LAYOUTRETURN4_ALL is empty, then no error		LAYOUTRETURN4_FSID or LAYOUTRETURN4_ALL is empty, then no error
	results. In the case of LAYOUTRETURN4_FILE, the byte-range		results. In the case of LAYOUTRETURN4_FILE, the byte-range
	specified is returned even if it is a subdivision of a layout		specified is returned even if it is a subdivision of a layout
	previously obtained with LAYOUTGET, a combination of multiple		previously obtained with LAYOUTGET, a combination of multiple
	layouts previously obtained with LAYOUTGET, or a combination		layouts previously obtained with LAYOUTGET, or a combination
	including some layouts previously obtained with LAYOUTGET,		including some layouts previously obtained with LAYOUTGET,
	and one or more subdivisions of such layouts. When the		and one or more subdivisions of such layouts. When the
	byte-range does not designate any bytes for which a layout		byte-range does not designate any bytes for which a layout
	is held for the specified file, client ID, layout type and		is held for the specified file, client ID, layout type and
	mode, no error results.		mode, no error results.
	See <xref target="bulk_layouts" /> for considerations with		See <xref target="bulk_layouts" format="default"/> for considerations wi th
	"bulk" return of layouts.		"bulk" return of layouts.
	</t>		</t>
	<t>		<t>
	The layout being returned may be a subset		The layout being returned may be a subset
	or superset of a layout specified by CB_LAYOUTRECALL. However,		or superset of a layout specified by CB_LAYOUTRECALL. However,
	if it is a subset, the recall is not complete until the full		if it is a subset, the recall is not complete until the full
	recalled scope has been returned. Recalled scope refers to the		recalled scope has been returned. Recalled scope refers to the
	byte-range in the case of LAYOUTRETURN4_FILE, the use of		byte-range in the case of LAYOUTRETURN4_FILE, the use of
	LAYOUTRETURN4_FSID, or the use of LAYOUTRETURN4_ALL. There must		LAYOUTRETURN4_FSID, or the use of LAYOUTRETURN4_ALL. There must
	be a LAYOUTRETURN with a matching scope to complete the return		be a LAYOUTRETURN with a matching scope to complete the return
	even if all current layout ranges have been previously individually		even if all current layout ranges have been previously individually
	returned.		returned.
	</t>		</t>
	<t>		<t>
	For all lr_returntype values, an iomode of LAYOUTIOMODE4_ANY		For all lr_returntype values, an iomode of LAYOUTIOMODE4_ANY
	specifies that all layouts that match the other arguments to		specifies that all layouts that match the other arguments to
	LAYOUTRETURN (i.e., client ID, lora_layout_type, and one of		LAYOUTRETURN (i.e., client ID, lora_layout_type, and one of
	current filehandle and range; fsid derived from current		current filehandle and range; fsid derived from current
	filehandle; or LAYOUTRETURN4_ALL) are being returned.		filehandle; or LAYOUTRETURN4_ALL) are being returned.
	</t>		</t>
	<t>		<t>
	In the case that lr_returntype is LAYOUTRETURN4_FILE, the		In the case that lr_returntype is LAYOUTRETURN4_FILE, the
	lrf_stateid provided by the client is a layout stateid as		lrf_stateid provided by the client is a layout stateid as
	returned from previous layout operations. Note that the "seqid"		returned from previous layout operations. Note that the "seqid"
	field of lrf_stateid MUST NOT be zero. See Sections		field of lrf_stateid <bcp14>MUST NOT</bcp14> be zero. See Sections
	<xref target="stateid" format="counter" />, <xref		<xref target="stateid" format="counter"/>, <xref target="layout_stateid" f
	target="layout_stateid" format="counter" />, and		ormat="counter"/>, and
	<xref target="pnfs_operation_sequencing" format="counter" /> for a further		<xref target="pnfs_operation_sequencing" format="counter"/> for a further
	discussion and requirements.		discussion and requirements.
	</t>		</t>
	<t>		<t>
	Return of a layout or all layouts does not invalidate the		Return of a layout or all layouts does not invalidate the
	mapping of storage device ID to a storage device address. The		mapping of storage device ID to a storage device address. The
	mapping remains in effect until specifically changed or deleted via		mapping remains in effect until specifically changed or deleted via
	device ID notification callbacks.		device ID notification callbacks.
	Of course if there are no remaining		Of course if there are no remaining
	layouts that refer to a previously used device ID, the server is		layouts that refer to a previously used device ID, the server is
	free to delete a device ID without a notification callback, which		free to delete a device ID without a notification callback, which
	will be the case when notifications are not in effect.		will be the case when notifications are not in effect.
	</t>		</t>
	<t>		<t>
	If the lora_reclaim field is set to TRUE, the		If the lora_reclaim field is set to TRUE, the
	client is attempting to return a layout that		client is attempting to return a layout that
	was acquired before the restart of the metadata		was acquired before the restart of the metadata
	server during the metadata server's grace period.		server during the metadata server's grace period.
	When returning layouts that were acquired during		When returning layouts that were acquired during
	the metadata server's grace period, the client MUST set the		the metadata server's grace period, the client <bcp14>MUST</bcp14> set the
	lora_reclaim field to FALSE. The lora_reclaim field		lora_reclaim field to FALSE. The lora_reclaim field
	MUST be set to FALSE also when lr_layoutreturn is		<bcp14>MUST</bcp14> be set to FALSE also when lr_layoutreturn is
	LAYOUTRETURN4_FSID or LAYOUTRETURN4_ALL. See <xref		LAYOUTRETURN4_FSID or LAYOUTRETURN4_ALL. See <xref target="OP_LAYOUTCOMMIT
	target="OP_LAYOUTCOMMIT">LAYOUTCOMMIT </xref> for		" format="default">LAYOUTCOMMIT </xref> for
	more details.		more details.
	</t>		</t>
	<t>		<t>
	Layouts may be returned when recalled or voluntarily (i.e.,		Layouts may be returned when recalled or voluntarily (i.e.,
	before the server has recalled them). In either case, the client		before the server has recalled them). In either case, the client
	must properly propagate state changed under the context of the		must properly propagate state changed under the context of the
	layout to the storage device(s) or to the metadata server before		layout to the storage device(s) or to the metadata server before
	returning the layout.		returning the layout.
	</t>		</t>
	<t>		<t>
	If the client returns the layout in response to a		If the client returns the layout in response to a
	CB_LAYOUTRECALL where the lor_recalltype field of the		CB_LAYOUTRECALL where the lor_recalltype field of the
	clora_recall field was LAYOUTRECALL4_FILE, the client		clora_recall field was LAYOUTRECALL4_FILE, the client
	should use the lor_stateid value from CB_LAYOUTRECALL		should use the lor_stateid value from CB_LAYOUTRECALL
	as the value for lrf_stateid. Otherwise, it should		as the value for lrf_stateid. Otherwise, it should
	use logr_stateid (from a previous LAYOUTGET result)		use logr_stateid (from a previous LAYOUTGET result)
	or lorr_stateid (from a previous LAYRETURN result).		or lorr_stateid (from a previous LAYRETURN result).
	This is done to indicate the point in time (in terms		This is done to indicate the point in time (in terms
	of layout stateid transitions) when the recall was		of layout stateid transitions) when the recall was
	sent. The client uses the precise lora_recallstateid		sent. The client uses the precise lora_recallstateid
	value and MUST NOT set the stateid's seqid to		value and <bcp14>MUST NOT</bcp14> set the stateid's seqid to
	zero; otherwise, NFS4ERR_BAD_STATEID MUST be		zero; otherwise, NFS4ERR_BAD_STATEID <bcp14>MUST</bcp14> be
	returned. NFS4ERR_OLD_STATEID can be returned if		returned. NFS4ERR_OLD_STATEID can be returned if
	the client is using an old seqid, and the server		the client is using an old seqid, and the server
	knows the client should not be using the old		knows the client should not be using the old
	seqid. For example, the client uses the seqid on slot 1 of		seqid. For example, the client uses the seqid on slot 1 of
	the session, receives the response with the new		the session, receives the response with the new
	seqid, and uses the slot to send another request		seqid, and uses the slot to send another request
	with the old seqid.		with the old seqid.
	</t>		</t>
	<t>		<t>
	If a client fails to return a layout		If a client fails to return a layout
	in a timely manner, then the metadata server SHOULD use its		in a timely manner, then the metadata server <bcp14>SHOULD</bcp14> use its
	control protocol with the storage devices to fence the client		control protocol with the storage devices to fence the client
	from accessing the data referenced by the layout. See		from accessing the data referenced by the layout. See
	<xref target="recalling_layout" /> for more details.		<xref target="recalling_layout" format="default"/> for more details.
	</t>		</t>
	<t>		<t>
	If the LAYOUTRETURN request sets the lora_reclaim field to TRUE after		If the LAYOUTRETURN request sets the lora_reclaim field to TRUE after
	the metadata server's grace period, NFS4ERR_NO_GRACE is returned.		the metadata server's grace period, NFS4ERR_NO_GRACE is returned.
	</t>		</t>
	<t>		<t>
	If the LAYOUTRETURN request sets the lora_reclaim field to TRUE		If the LAYOUTRETURN request sets the lora_reclaim field to TRUE
	and lr_returntype is set to LAYOUTRETURN4_FSID or LAYOUTRETURN4_ALL,		and lr_returntype is set to LAYOUTRETURN4_FSID or LAYOUTRETURN4_ALL,
	NFS4ERR_INVAL is returned.		NFS4ERR_INVAL is returned.
	</t>		</t>
	<t>		<t>
	If the client sets the lr_returntype field to		If the client sets the lr_returntype field to
	LAYOUTRETURN4_FILE, then the lrs_stateid field		LAYOUTRETURN4_FILE, then the lrs_stateid field
	will represent the layout stateid as updated for		will represent the layout stateid as updated for
	this operation's processing; the current stateid		this operation's processing; the current stateid
	will also be updated to match the returned value.		will also be updated to match the returned value.
	If the last byte of any layout for the current		If the last byte of any layout for the current
	file, client ID, and layout type is being returned		file, client ID, and layout type is being returned
	and there are no remaining pending CB_LAYOUTRECALL		and there are no remaining pending CB_LAYOUTRECALL
	operations for which a LAYOUTRETURN operation must be		operations for which a LAYOUTRETURN operation must be
	done, lrs_present MUST be FALSE, and no stateid		done, lrs_present <bcp14>MUST</bcp14> be FALSE, and no stateid
	will be returned. In addition, the COMPOUND request's current		will be returned. In addition, the COMPOUND request's current
	stateid will be set to the all-zeroes special stateid		stateid will be set to the all-zeroes special stateid
	(see <xref target="current_stateid"/>). The server		(see <xref target="current_stateid" format="default"/>). The server
	MUST reject with NFS4ERR_BAD_STATEID any further		<bcp14>MUST</bcp14> reject with NFS4ERR_BAD_STATEID any further
	use of the current stateid in that COMPOUND until		use of the current stateid in that COMPOUND until
	the current stateid is re-established by a later		the current stateid is re-established by a later
	stateid-returning operation.		stateid-returning operation.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle retains its value.		On success, the current filehandle retains its value.
	</t>		</t>
	<t>		<t>
	If the EXCHGID4_FLAG_BIND_PRINC_STATEID		If the EXCHGID4_FLAG_BIND_PRINC_STATEID
	capability is set on the client ID (see <xref		capability is set on the client ID (see <xref target="OP_EXCHANGE_ID" forma
	target="OP_EXCHANGE_ID"/>), the server will		t="default"/>), the server will
	require that the principal, security flavor,		require that the principal, security flavor,
	and if applicable, the GSS mechanism, combination		and if applicable, the GSS mechanism, combination
	that acquired the layout also be the one to send		that acquired the layout also be the one to send
	LAYOUTRETURN. This might not be possible		LAYOUTRETURN. This might not be possible
	if credentials for the principal are no		if credentials for the principal are no
	longer available. The server will allow the		longer available. The server will allow the
	machine credential or SSV credential (see <xref		machine credential or SSV credential (see <xref target="OP_EXCHANGE_ID" for
	target="OP_EXCHANGE_ID" />) to send LAYOUTRETURN		mat="default"/>) to send LAYOUTRETURN
	if LAYOUTRETURN's operation code was set in the		if LAYOUTRETURN's operation code was set in the
	spo_must_allow result of EXCHANGE_ID.		spo_must_allow result of EXCHANGE_ID.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_LAYOUTRETURN_IMPLEMENTATION" title="IMPLEMEN		<section toc="exclude" anchor="OP_LAYOUTRETURN_IMPLEMENTATION" numbered=
	TATION">		"true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	The final LAYOUTRETURN operation in response to a CB_LAYOUTRECALL		The final LAYOUTRETURN operation in response to a CB_LAYOUTRECALL
	callback MUST be serialized with any outstanding, intersecting		callback <bcp14>MUST</bcp14> be serialized with any outstanding, intersectin g
	LAYOUTRETURN operations. Note that it is possible that while a		LAYOUTRETURN operations. Note that it is possible that while a
	client is returning the layout for some recalled range, the server		client is returning the layout for some recalled range, the server
	may recall a superset of that range (e.g., LAYOUTRECALL4_ALL); the final		may recall a superset of that range (e.g., LAYOUTRECALL4_ALL); the final
	return operation for the latter must block until the former layout		return operation for the latter must block until the former layout
	recall is done.		recall is done.
	</t>		</t>
	<t>		<t>
	Returning all layouts in a file system using LAYOUTRETURN4_FSID is		Returning all layouts in a file system using LAYOUTRETURN4_FSID is
	typically done in response to a CB_LAYOUTRECALL for that file system		typically done in response to a CB_LAYOUTRECALL for that file system
	as the final return operation. Similarly, LAYOUTRETURN4_ALL		as the final return operation. Similarly, LAYOUTRETURN4_ALL
	is used in response to a recall callback for all layouts. It is		is used in response to a recall callback for all layouts. It is
	possible that the client already returned some outstanding layouts		possible that the client already returned some outstanding layouts
	via individual LAYOUTRETURN calls and the call for		via individual LAYOUTRETURN calls and the call for
	LAYOUTRETURN4_FSID or LAYOUTRETURN4_ALL marks the end of the		LAYOUTRETURN4_FSID or LAYOUTRETURN4_ALL marks the end of the
	LAYOUTRETURN sequence. See <xref target="recall_robustness" />		LAYOUTRETURN sequence. See <xref target="recall_robustness" format="default "/>
	for more details.		for more details.
	</t>		</t>
	<t>		<t>
	Once the client has returned all layouts referring to a particular		Once the client has returned all layouts referring to a particular
	device ID, the server MAY delete the device ID.		device ID, the server <bcp14>MAY</bcp14> delete the device ID.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_SECINFO_NO_NAME" numbered="true" toc="default">
	$ -->		<name>Operation 52: SECINFO_NO_NAME - Get Security on Unnamed Object</na
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		me>
	<!-- Copyright (C) The Internet Society (2006) -->		<section toc="exclude" anchor="OP_SECINFO_NO_NAME_ARGUMENT" numbered="tr
	<section title="Operation 52: SECINFO_NO_NAME - Get Security on Unnamed Object"		ue">
	anchor="OP_SECINFO_NO_NAME">		<name>ARGUMENT</name>
			<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_SECINFO_NO_NAME_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	enum secinfo_style4 {		enum secinfo_style4 {
	SECINFO_STYLE4_CURRENT_FH = 0,		SECINFO_STYLE4_CURRENT_FH = 0,
	SECINFO_STYLE4_PARENT = 1		SECINFO_STYLE4_PARENT = 1
	};		};
	/* CURRENT_FH: object or child directory */		/* CURRENT_FH: object or child directory */
	typedef secinfo_style4 SECINFO_NO_NAME4args;		typedef secinfo_style4 SECINFO_NO_NAME4args;
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_SECINFO_NO_NAME_RESULT" numbered="true
	</section>		">
	<section toc="exclude" anchor="OP_SECINFO_NO_NAME_RESULT" title="RESULT">		<name>RESULT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	/* CURRENTFH: consumed if status is NFS4_OK */		/* CURRENTFH: consumed if status is NFS4_OK */
	typedef SECINFO4res SECINFO_NO_NAME4res;		typedef SECINFO4res SECINFO_NO_NAME4res;
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_SECINFO_NO_NAME_DESCRIPTION" numbered=
	</section>		"true">
	<section toc="exclude" anchor="OP_SECINFO_NO_NAME_DESCRIPTION" title="DESCRIPT		<name>DESCRIPTION</name>
	ION">		<t>
	<t>
	Like the SECINFO operation, SECINFO_NO_NAME is used by the		Like the SECINFO operation, SECINFO_NO_NAME is used by the
	client to obtain a list of valid RPC authentication flavors for		client to obtain a list of valid RPC authentication flavors for
	a specific file object. Unlike SECINFO, SECINFO_NO_NAME only		a specific file object. Unlike SECINFO, SECINFO_NO_NAME only
	works with objects that are accessed by filehandle.		works with objects that are accessed by filehandle.
	</t>		</t>
	<t>		<t>
	There are two styles of SECINFO_NO_NAME, as determined by the		There are two styles of SECINFO_NO_NAME, as determined by the
	value of the secinfo_style4 enumeration. If SECINFO_STYLE4_CURRENT_FH is		value of the secinfo_style4 enumeration. If SECINFO_STYLE4_CURRENT_FH is
	passed, then SECINFO_NO_NAME is querying for the required		passed, then SECINFO_NO_NAME is querying for the required
	security for the current filehandle. If SECINFO_STYLE4_PARENT is passed, t hen		security for the current filehandle. If SECINFO_STYLE4_PARENT is passed, t hen
	SECINFO_NO_NAME is querying for the required security of the		SECINFO_NO_NAME is querying for the required security of the
	current filehandle's parent. If the style selected is SECINFO_STYLE4_PAREN T,		current filehandle's parent. If the style selected is SECINFO_STYLE4_PAREN T,
	then SECINFO should apply the same access methodology used for		then SECINFO should apply the same access methodology used for
	LOOKUPP when evaluating the traversal to the parent directory.		LOOKUPP when evaluating the traversal to the parent directory.
	Therefore, if the requester does not have the appropriate access		Therefore, if the requester does not have the appropriate access
	to LOOKUPP the parent, then SECINFO_NO_NAME must behave the same		to LOOKUPP the parent, then SECINFO_NO_NAME must behave the same
	way and return NFS4ERR_ACCESS.		way and return NFS4ERR_ACCESS.
	</t>		</t>
	<t>		<t>
	If PUTFH, PUTPUBFH, PUTROOTFH, or RESTOREFH returns		If PUTFH, PUTPUBFH, PUTROOTFH, or RESTOREFH returns
	NFS4ERR_WRONGSEC, then the client resolves the		NFS4ERR_WRONGSEC, then the client resolves the
	situation by sending a COMPOUND request that consists of		situation by sending a COMPOUND request that consists of
	PUTFH, PUTPUBFH, or PUTROOTFH immediately followed by		PUTFH, PUTPUBFH, or PUTROOTFH immediately followed by
	SECINFO_NO_NAME, style SECINFO_STYLE4_CURRENT_FH.		SECINFO_NO_NAME, style SECINFO_STYLE4_CURRENT_FH.
	See <xref target="Security_Service_Negotiation" />		See <xref target="Security_Service_Negotiation" format="default"/>
	for instructions on dealing with NFS4ERR_WRONGSEC error		for instructions on dealing with NFS4ERR_WRONGSEC error
	returns from PUTFH, PUTROOTFH, PUTPUBFH, or RESTOREFH.		returns from PUTFH, PUTROOTFH, PUTPUBFH, or RESTOREFH.
	</t>		</t>
	<t>		<t>
	If SECINFO_STYLE4_PARENT is specified and there is no parent		If SECINFO_STYLE4_PARENT is specified and there is no parent
	directory, SECINFO_NO_NAME MUST return NFS4ERR_NOENT.		directory, SECINFO_NO_NAME <bcp14>MUST</bcp14> return NFS4ERR_NOENT.
	</t>		</t>
	<t>		<t>
	On success, the current filehandle is consumed		On success, the current filehandle is consumed
	(see <xref target="aftersecinfo" />), and if the		(see <xref target="aftersecinfo" format="default"/>), and if the
	next operation after SECINFO_NO_NAME tries to use		next operation after SECINFO_NO_NAME tries to use
	the current filehandle, that operation will fail		the current filehandle, that operation will fail
	with the status NFS4ERR_NOFILEHANDLE.		with the status NFS4ERR_NOFILEHANDLE.
	</t>		</t>
	<t>		<t>
	Everything else about SECINFO_NO_NAME is the same as SECINFO.		Everything else about SECINFO_NO_NAME is the same as SECINFO.
	See the discussion on SECINFO (<xref target="OP_SECINFO_DESCRIPTION"/>).		See the discussion on SECINFO (<xref target="OP_SECINFO_DESCRIPTION" forma
	</t>		t="default"/>).
	</section>		</t>
	<section toc="exclude" anchor="OP_SECINFO_NO_NAME_IMPLEMENTATION" title="IMPLE		</section>
	MENTATION">		<section toc="exclude" anchor="OP_SECINFO_NO_NAME_IMPLEMENTATION" number
	<t>		ed="true">
	See the discussion on SECINFO (<xref target="OP_SECINFO_IMPLEMENTATION" />		<name>IMPLEMENTATION</name>
	).		<t>
	</t>		See the discussion on SECINFO (<xref target="OP_SECINFO_IMPLEMENTATION" fo
	</section>		rmat="default"/>).
	</section>		</t>
			</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		</section>
	$ -->		<section anchor="OP_SEQUENCE" numbered="true" toc="default">
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<name>Operation 53: SEQUENCE - Supply Per-Procedure Sequencing and Contr
	<!-- Copyright (C) The Internet Society (2006) -->		ol</name>
	<section anchor="OP_SEQUENCE" title="Operation 53: SEQUENCE - Supply Per-Procedu		<section toc="exclude" anchor="OP_SEQUENCE_ARGUMENT" numbered="true">
	re Sequencing and Control" >		<name>ARGUMENT</name>
			<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_SEQUENCE_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct SEQUENCE4args {		struct SEQUENCE4args {
	sessionid4 sa_sessionid;		sessionid4 sa_sessionid;
	sequenceid4 sa_sequenceid;		sequenceid4 sa_sequenceid;
	slotid4 sa_slotid;		slotid4 sa_slotid;
	slotid4 sa_highest_slotid;		slotid4 sa_highest_slotid;
	bool sa_cachethis;		bool sa_cachethis;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_SEQUENCE_RESULT" numbered="true">
	</figure>		<name>RESULT</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_SEQUENCE_RESULT" title="RESULT">
	<figure>
	<artwork>
	const SEQ4_STATUS_CB_PATH_DOWN = 0x00000001;		const SEQ4_STATUS_CB_PATH_DOWN = 0x00000001;
	const SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRING = 0x00000002;		const SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRING = 0x00000002;
	const SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRED = 0x00000004;		const SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRED = 0x00000004;
	const SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED = 0x00000008;		const SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED = 0x00000008;
	const SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED = 0x00000010;		const SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED = 0x00000010;
	const SEQ4_STATUS_ADMIN_STATE_REVOKED = 0x00000020;		const SEQ4_STATUS_ADMIN_STATE_REVOKED = 0x00000020;
	const SEQ4_STATUS_RECALLABLE_STATE_REVOKED = 0x00000040;		const SEQ4_STATUS_RECALLABLE_STATE_REVOKED = 0x00000040;
	const SEQ4_STATUS_LEASE_MOVED = 0x00000080;		const SEQ4_STATUS_LEASE_MOVED = 0x00000080;
	const SEQ4_STATUS_RESTART_RECLAIM_NEEDED = 0x00000100;		const SEQ4_STATUS_RESTART_RECLAIM_NEEDED = 0x00000100;
	const SEQ4_STATUS_CB_PATH_DOWN_SESSION = 0x00000200;		const SEQ4_STATUS_CB_PATH_DOWN_SESSION = 0x00000200;
	skipping to change at line 39086 ¶		skipping to change at line 39042 ¶
	slotid4 sr_highest_slotid;		slotid4 sr_highest_slotid;
	slotid4 sr_target_highest_slotid;		slotid4 sr_target_highest_slotid;
	uint32_t sr_status_flags;		uint32_t sr_status_flags;
	};		};
	union SEQUENCE4res switch (nfsstat4 sr_status) {		union SEQUENCE4res switch (nfsstat4 sr_status) {
	case NFS4_OK:		case NFS4_OK:
	SEQUENCE4resok sr_resok4;		SEQUENCE4resok sr_resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_SEQUENCE_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_SEQUENCE_DESCRIPTION" title="DESCRIPTION">
	<t>
	The SEQUENCE operation is		The SEQUENCE operation is
	used by the server to implement session request control		used by the server to implement session request control
	and the reply cache semantics.		and the reply cache semantics.
	</t>		</t>
	<t>		<t>
	SEQUENCE MUST appear as the first operation of any COMPOUND		SEQUENCE <bcp14>MUST</bcp14> appear as the first operation of any COMPOUND
	in which it appears. The error NFS4ERR_SEQUENCE_POS will be		in which it appears. The error NFS4ERR_SEQUENCE_POS will be
	returned when it is found in any position in a COMPOUND		returned when it is found in any position in a COMPOUND
	beyond the first. Operations other than SEQUENCE, BIND_CONN_TO_SESSION,		beyond the first. Operations other than SEQUENCE, BIND_CONN_TO_SESSION,
	EXCHANGE_ID, CREATE_SESSION, and DESTROY_SESSION,		EXCHANGE_ID, CREATE_SESSION, and DESTROY_SESSION,
	MUST NOT appear as the first operation in a		<bcp14>MUST NOT</bcp14> appear as the first operation in a
	COMPOUND. Such operations MUST yield the error NFS4ERR_OP_NOT_IN_SESSION		COMPOUND. Such operations <bcp14>MUST</bcp14> yield the error NFS4ERR_OP_
			NOT_IN_SESSION
	if they do appear at the start of a COMPOUND.		if they do appear at the start of a COMPOUND.
	</t>		</t>
	<t>		<t>
	If SEQUENCE is received on a connection not associated with the		If SEQUENCE is received on a connection not associated with the
	session via CREATE_SESSION or BIND_CONN_TO_SESSION, and		session via CREATE_SESSION or BIND_CONN_TO_SESSION, and
	connection association enforcement is enabled		connection association enforcement is enabled
	(see <xref target="OP_EXCHANGE_ID" />), then		(see <xref target="OP_EXCHANGE_ID" format="default"/>), then
	the server returns NFS4ERR_CONN_NOT_BOUND_TO_SESSION.		the server returns NFS4ERR_CONN_NOT_BOUND_TO_SESSION.
	</t>		</t>
	<t>		<t>
	The sa_sessionid argument identifies the session to which this		The sa_sessionid argument identifies the session to which this
	request applies. The sr_sessionid result MUST equal		request applies. The sr_sessionid result <bcp14>MUST</bcp14> equal
	sa_sessionid.		sa_sessionid.
	</t>		</t>
	<t>		<t>
	The sa_slotid argument is the index in the reply cache		The sa_slotid argument is the index in the reply cache
	for the request. The sa_sequenceid field is the sequence		for the request. The sa_sequenceid field is the sequence
	number of the request for the reply cache entry (slot).		number of the request for the reply cache entry (slot).
	The sr_slotid result MUST equal sa_slotid. The sr_sequenceid		The sr_slotid result <bcp14>MUST</bcp14> equal sa_slotid. The sr_sequenceid
	result MUST equal sa_sequenceid.		result <bcp14>MUST</bcp14> equal sa_sequenceid.
	</t>		</t>
	<t>		<t>
	The sa_highest_slotid argument is the highest slot ID		The sa_highest_slotid argument is the highest slot ID
	for which the client has a request outstanding; it could be		for which the client has a request outstanding; it could be
	equal to sa_slotid.		equal to sa_slotid.
	The server returns two "highest_slotid" values: sr_highest_slotid		The server returns two "highest_slotid" values: sr_highest_slotid
	and sr_target_highest_slotid. The former is the highest slot ID		and sr_target_highest_slotid. The former is the highest slot ID
	the server will accept in future SEQUENCE operation, and		the server will accept in future SEQUENCE operation, and
	SHOULD NOT be less than the value of sa_highest_slotid		<bcp14>SHOULD NOT</bcp14> be less than the value of sa_highest_slotid
	(but see		(but see
	<xref target="Slot_Identifiers_and_Server_Reply_Cache" />		<xref target="Slot_Identifiers_and_Server_Reply_Cache" format="default"/>
	for an exception).		for an exception).
	The latter is the highest slot ID the server would prefer the		The latter is the highest slot ID the server would prefer the
	client use on a future SEQUENCE operation.		client use on a future SEQUENCE operation.
	</t>		</t>
	<t>		<t>
	If sa_cachethis is TRUE, then the client is requesting that		If sa_cachethis is TRUE, then the client is requesting that
	the server cache the entire		the server cache the entire
	reply in the server's reply cache; therefore, the server MUST		reply in the server's reply cache; therefore, the server <bcp14>MUST</bcp14
	cache the reply (see <xref target="optional_reply_caching" />).		>
	The server MAY cache the reply if sa_cachethis is FALSE.		cache the reply (see <xref target="optional_reply_caching" format="default"
			/>).
			The server <bcp14>MAY</bcp14> cache the reply if sa_cachethis is FALSE.
	If the server does not cache the entire reply, it		If the server does not cache the entire reply, it
	MUST still record that it executed the request at		<bcp14>MUST</bcp14> still record that it executed the request at
	the specified slot and sequence ID.		the specified slot and sequence ID.
	</t>		</t>
	<t>		<t>
	The response to the SEQUENCE operation contains a		The response to the SEQUENCE operation contains a
	word of status flags (sr_status_flags) that can		word of status flags (sr_status_flags) that can
	provide to the client information related to the		provide to the client information related to the
	status of the client's lock state and communications		status of the client's lock state and communications
	paths. Note that any status bits relating to lock		paths. Note that any status bits relating to lock
	state MAY be reset when lock state is lost due to a		state <bcp14>MAY</bcp14> be reset when lock state is lost due to a
	server restart (even if the session is persistent across		server restart (even if the session is persistent across
	restarts; session persistence does not imply		restarts; session persistence does not imply
	lock state persistence)		lock state persistence)
	or the establishment of a new client		or the establishment of a new client
	instance.		instance.
	<list style='hanging'>		</t>
	<t hangText="SEQ4_STATUS_CB_PATH_DOWN"><vspace />		<dl newline="true" spacing="normal">
			<dt>SEQ4_STATUS_CB_PATH_DOWN</dt>
			<dd>
	When set, indicates that the client has no		When set, indicates that the client has no
	operational backchannel path for any session		operational backchannel path for any session
	associated with the client ID, making it		associated with the client ID, making it
	necessary for the client to re-establish one.		necessary for the client to re-establish one.
	This bit		This bit
	remains set on all SEQUENCE responses on all sessions		remains set on all SEQUENCE responses on all sessions
	associated with the client ID		associated with the client ID
	until at least one backchannel is		until at least one backchannel is
	available on any session associated with the client ID.		available on any session associated with the client ID.
	If the client fails to re-establish a		If the client fails to re-establish a
	backchannel for the client ID, it is subject to		backchannel for the client ID, it is subject to
	having recallable state revoked.		having recallable state revoked.
	</t>		</dd>
	<t hangText="SEQ4_STATUS_CB_PATH_DOWN_SESSION"><vspace />		<dt>SEQ4_STATUS_CB_PATH_DOWN_SESSION</dt>
			<dd>
	When set, indicates that the session has		When set, indicates that the session has
	no operational backchannel. There are two reasons		no operational backchannel. There are two reasons
	why SEQ4_STATUS_CB_PATH_DOWN_SESSION may be set and not		why SEQ4_STATUS_CB_PATH_DOWN_SESSION may be set and not
	SEQ4_STATUS_CB_PATH_DOWN. First is that a callback operation		SEQ4_STATUS_CB_PATH_DOWN. First is that a callback operation
	that applies specifically to the		that applies specifically to the
	session (e.g., CB_RECALL_SLOT, see <xref		session (e.g., CB_RECALL_SLOT, see <xref target="OP_CB_RECALL_SLOT" fo
	target="OP_CB_RECALL_SLOT" />) needs to be sent.		rmat="default"/>) needs to be sent.
	Second is that the server did send a callback operation,		Second is that the server did send a callback operation,
	but the connection was lost before the reply. The		but the connection was lost before the reply. The
	server cannot be sure whether or not the client received the		server cannot be sure whether or not the client received the
	callback operation, and so, per rules on		callback operation, and so, per rules on
	request retry, the server MUST retry the callback		request retry, the server <bcp14>MUST</bcp14> retry the callback
	operation over the same session. The		operation over the same session. The
	SEQ4_STATUS_CB_PATH_DOWN_SESSION bit is the indication		SEQ4_STATUS_CB_PATH_DOWN_SESSION bit is the indication
	to the client that it needs to associate a connection		to the client that it needs to associate a connection
	to the session's backchannel.		to the session's backchannel.
	This bit remains set on all SEQUENCE responses of the		This bit remains set on all SEQUENCE responses of the
	session until a connection is associated with the		session until a connection is associated with the
	session's a backchannel.		session's a backchannel.
	If the client fails to re-establish a		If the client fails to re-establish a
	backchannel for the session, it is subject to		backchannel for the session, it is subject to
	having recallable state revoked.		having recallable state revoked.
	</t>		</dd>
	<t hangText="SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRING"><vspace />		<dt>SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRING</dt>
			<dd>
			<t>
	When set, indicates that all GSS contexts or RPCSEC_GSS handles		When set, indicates that all GSS contexts or RPCSEC_GSS handles
	assigned to the session's backchannel will expire within a		assigned to the session's backchannel will expire within a
	period equal to the lease time. This bit remains set on all		period equal to the lease time. This bit remains set on all
	SEQUENCE replies until at least one of the following are true:		SEQUENCE replies until at least one of the following are true:
	<list style='symbols'>		</t>
			<ul spacing="normal">
	<t>		<li>
	All SSV RPCSEC_GSS handles on the session's backchannel		All SSV RPCSEC_GSS handles on the session's backchannel
	have been destroyed and all non-SSV GSS contexts have expired.		have been destroyed and all non-SSV GSS contexts have expired.
	</t>		</li>
	<t>		<li>
	At least one more SSV RPCSEC_GSS handle has been added to		At least one more SSV RPCSEC_GSS handle has been added to
	the backchannel.		the backchannel.
	</t>		</li>
	<t>		<li>
	The expiration time of at least one non-SSV GSS context		The expiration time of at least one non-SSV GSS context
	of an RPCSEC_GSS handle		of an RPCSEC_GSS handle
	is beyond the lease period from the current		is beyond the lease period from the current
	time (relative to the time of when a SEQUENCE		time (relative to the time of when a SEQUENCE
	response was sent)		response was sent)
	</t>		</li>
			</ul>
	</list>		</dd>
	</t>		<dt>SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRED</dt>
	<t hangText="SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRED"><vspace />		<dd>
	When set, indicates all non-SSV GSS contexts and all		When set, indicates all non-SSV GSS contexts and all
	SSV RPCSEC_GSS handles assigned		SSV RPCSEC_GSS handles assigned
	to the session's backchannel have expired or have been		to the session's backchannel have expired or have been
	destroyed.		destroyed.
	This bit remains set on all SEQUENCE replies		This bit remains set on all SEQUENCE replies
	until at least one non-expired non-SSV GSS context for the		until at least one non-expired non-SSV GSS context for the
	session's backchannel has been established or at least one		session's backchannel has been established or at least one
	SSV RPCSEC_GSS handle has been assigned to the backchannel.		SSV RPCSEC_GSS handle has been assigned to the backchannel.
	</t>		</dd>
	<t hangText="SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED"><vspace />		<dt>SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED</dt>
			<dd>
	When set, indicates that the lease has expired		When set, indicates that the lease has expired
	and as a result the server released all of the		and as a result the server released all of the
	client's locking state. This status bit remains		client's locking state. This status bit remains
	set on all SEQUENCE replies until the loss of		set on all SEQUENCE replies until the loss of
	all such locks has been acknowledged by use of		all such locks has been acknowledged by use of
	FREE_STATEID (see <xref target="OP_FREE_STATEID"		FREE_STATEID (see <xref target="OP_FREE_STATEID" format="default"/>),
	/>), or by establishing a new client instance by		or by establishing a new client instance by
	destroying all sessions (via DESTROY_SESSION),		destroying all sessions (via DESTROY_SESSION),
	the client ID (via DESTROY_CLIENTID), and then		the client ID (via DESTROY_CLIENTID), and then
	invoking EXCHANGE_ID and CREATE_SESSION to		invoking EXCHANGE_ID and CREATE_SESSION to
	establish a new client ID.		establish a new client ID.
	</t>		</dd>
	<t hangText="SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED"><vspace />		<dt>SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED</dt>
			<dd>
	When set, indicates that some subset of the client's locks		When set, indicates that some subset of the client's locks
	have been revoked due to expiration of the lease period		have been revoked due to expiration of the lease period
	followed by another client's conflicting LOCK operation.		followed by another client's conflicting LOCK operation.
	This status bit remains set on all SEQUENCE replies		This status bit remains set on all SEQUENCE replies
	until the loss of all		until the loss of all
	such locks has been acknowledged by use of FREE_STATEID.		such locks has been acknowledged by use of FREE_STATEID.
	</t>		</dd>
	<t hangText="SEQ4_STATUS_ADMIN_STATE_REVOKED"><vspace />		<dt>SEQ4_STATUS_ADMIN_STATE_REVOKED</dt>
			<dd>
	When set, indicates that one or more locks have been revoked		When set, indicates that one or more locks have been revoked
	without expiration of the lease period, due to administrative		without expiration of the lease period, due to administrative
	action. This status bit remains set on all SEQUENCE replies		action. This status bit remains set on all SEQUENCE replies
	until the loss of all		until the loss of all
	such locks has been acknowledged by use of FREE_STATEID.		such locks has been acknowledged by use of FREE_STATEID.
	</t>		</dd>
	<t hangText="SEQ4_STATUS_RECALLABLE_STATE_REVOKED"><vspace />		<dt>SEQ4_STATUS_RECALLABLE_STATE_REVOKED</dt>
			<dd>
	When set, indicates that one or more recallable		When set, indicates that one or more recallable
	objects have been revoked without expiration		objects have been revoked without expiration
	of the lease period, due to the client's		of the lease period, due to the client's
	failure to return them when recalled, which		failure to return them when recalled, which
	may be a consequence of there being no working		may be a consequence of there being no working
	backchannel and the client failing to re-establish		backchannel and the client failing to re-establish
	a backchannel per the SEQ4_STATUS_CB_PATH_DOWN,		a backchannel per the SEQ4_STATUS_CB_PATH_DOWN,
	SEQ4_STATUS_CB_PATH_DOWN_SESSION, or		SEQ4_STATUS_CB_PATH_DOWN_SESSION, or
	SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRED status flags.		SEQ4_STATUS_CB_GSS_CONTEXTS_EXPIRED status flags.
	This status bit remains set on all SEQUENCE		This status bit remains set on all SEQUENCE
	replies until the loss of all such locks has		replies until the loss of all such locks has
	been acknowledged by use of FREE_STATEID.		been acknowledged by use of FREE_STATEID.
	</t>		</dd>
	<t hangText="SEQ4_STATUS_LEASE_MOVED"><vspace />		<dt>SEQ4_STATUS_LEASE_MOVED</dt>
			<dd>
	When set, indicates that responsibility for lease renewal has		When set, indicates that responsibility for lease renewal has
	been transferred to one or more new servers. This condition		been transferred to one or more new servers. This condition
	will continue until the client receives an NFS4ERR_MOVED		will continue until the client receives an NFS4ERR_MOVED
	error and the server receives the subsequent GETATTR for the		error and the server receives the subsequent GETATTR for the
	fs_locations or fs_locations_info attribute for an access to		fs_locations or fs_locations_info attribute for an access to
	each file system for which a lease has been moved to a new		each file system for which a lease has been moved to a new
	server. See <xref target="transferred_lease" />.		server. See <xref target="transferred_lease" format="default"/>.
	</t>		</dd>
	<t hangText="SEQ4_STATUS_RESTART_RECLAIM_NEEDED"><vspace />		<dt>SEQ4_STATUS_RESTART_RECLAIM_NEEDED</dt>
			<dd>
	When set, indicates that due to server		When set, indicates that due to server
	restart, the client must reclaim locking state.		restart, the client must reclaim locking state.
	Until the client sends a global RECLAIM_COMPLETE		Until the client sends a global RECLAIM_COMPLETE
	(<xref target="OP_RECLAIM_COMPLETE" />), every		(<xref target="OP_RECLAIM_COMPLETE" format="default"/>), every
	SEQUENCE operation will return		SEQUENCE operation will return
	SEQ4_STATUS_RESTART_RECLAIM_NEEDED.		SEQ4_STATUS_RESTART_RECLAIM_NEEDED.
	</t>		</dd>
	<t hangText="SEQ4_STATUS_BACKCHANNEL_FAULT"><vspace />		<dt>SEQ4_STATUS_BACKCHANNEL_FAULT</dt>
			<dd>
	The server has encountered an unrecoverable fault		The server has encountered an unrecoverable fault
	with the backchannel (e.g., it has lost track of the		with the backchannel (e.g., it has lost track of the
	sequence ID for a slot in the backchannel). The		sequence ID for a slot in the backchannel). The
	client MUST stop sending more requests on the		client <bcp14>MUST</bcp14> stop sending more requests on the
	session's fore channel, wait for all outstanding requests to		session's fore channel, wait for all outstanding requests to
	complete on the fore and back channel, and then		complete on the fore and back channel, and then
	destroy the session.		destroy the session.
	</t>		</dd>
	<t hangText="SEQ4_STATUS_DEVID_CHANGED"><vspace />		<dt>SEQ4_STATUS_DEVID_CHANGED</dt>
			<dd>
	The client is using device ID notifications and the server		The client is using device ID notifications and the server
	has changed a device ID mapping held by the client. This		has changed a device ID mapping held by the client. This
	flag will stay present until the client has obtained the new		flag will stay present until the client has obtained the new
	mapping with GETDEVICEINFO.		mapping with GETDEVICEINFO.
	</t>		</dd>
	<t hangText="SEQ4_STATUS_DEVID_DELETED"><vspace />		<dt>SEQ4_STATUS_DEVID_DELETED</dt>
			<dd>
	The client is using device ID notifications and the server		The client is using device ID notifications and the server
	has deleted a device ID mapping held by the client.		has deleted a device ID mapping held by the client.
	This flag will stay in effect until the client sends a GETDEVICEINFO		This flag will stay in effect until the client sends a GETDEVICEINFO
	on the device ID with a null value in the argument gdia_notify_types.		on the device ID with a null value in the argument gdia_notify_types.
	</t>		</dd>
	</list>		</dl>
	</t>		<t>
	<t>
	The value of the sa_sequenceid argument relative to		The value of the sa_sequenceid argument relative to
	the cached sequence ID on the slot falls into one		the cached sequence ID on the slot falls into one
	of three cases.		of three cases.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	If the difference between sa_sequenceid and		If the difference between sa_sequenceid and
	the server's cached sequence ID at the slot ID		the server's cached sequence ID at the slot ID
	is two (2) or more,		is two (2) or more,
	or if sa_sequenceid is less		or if sa_sequenceid is less
	than the cached sequence ID (accounting		than the cached sequence ID (accounting
	for wraparound of the unsigned sequence ID value),		for wraparound of the unsigned sequence ID value),
	then the server MUST return NFS4ERR_SEQ_MISORDERED.		then the server <bcp14>MUST</bcp14> return NFS4ERR_SEQ_MISORDERED.
	</t>		</li>
	<t>		<li>
	If sa_sequenceid and the cached sequence ID are		If sa_sequenceid and the cached sequence ID are
	the same, this is a retry, and the server replies		the same, this is a retry, and the server replies
	with what is recorded in the reply		with what is recorded in the reply
	cache.		cache.
	The lease is possibly renewed as described below.		The lease is possibly renewed as described below.
	</t>		</li>
	<t>		<li>
	If sa_sequenceid is one greater (accounting for		If sa_sequenceid is one greater (accounting for
	wraparound) than the cached sequence ID, then		wraparound) than the cached sequence ID, then
	this is a new request, and the slot's sequence		this is a new request, and the slot's sequence
	ID is incremented. The operations subsequent to		ID is incremented. The operations subsequent to
	SEQUENCE, if any, are processed. If there are no		SEQUENCE, if any, are processed. If there are no
	other operations, the only other effects are to		other operations, the only other effects are to
	cache the SEQUENCE reply in the slot, maintain the		cache the SEQUENCE reply in the slot, maintain the
	session's activity, and possibly renew the lease.		session's activity, and possibly renew the lease.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	If the client reuses a slot ID and sequence ID for		If the client reuses a slot ID and sequence ID for
	a completely different request, the server MAY treat		a completely different request, the server <bcp14>MAY</bcp14> treat
	the request as if it is a retry of what it has already		the request as if it is a retry of what it has already
	executed. The server MAY however detect the client's		executed. The server <bcp14>MAY</bcp14> however detect the client's
	illegal reuse and return NFS4ERR_SEQ_FALSE_RETRY.		illegal reuse and return NFS4ERR_SEQ_FALSE_RETRY.
	</t>		</t>
	<t>		<t>
	If SEQUENCE returns an error, then the state of the		If SEQUENCE returns an error, then the state of the
	slot (sequence ID, cached reply) MUST NOT change,		slot (sequence ID, cached reply) <bcp14>MUST NOT</bcp14> change,
	and the associated lease MUST NOT be renewed.		and the associated lease <bcp14>MUST NOT</bcp14> be renewed.
	</t>		</t>
	<t>		<t>
	If SEQUENCE returns NFS4_OK, then the associated		If SEQUENCE returns NFS4_OK, then the associated
	lease MUST be renewed (see <xref target="lease_renewal"/>),		lease <bcp14>MUST</bcp14> be renewed (see <xref target="lease_renewal" form at="default"/>),
	except if SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED is		except if SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED is
	returned in sr_status_flags.		returned in sr_status_flags.
	</t>		</t>
			</section>
	</section>		<section toc="exclude" anchor="OP_SEQUENCE_IMPLEMENTATION" numbered="tru
	<section toc="exclude" anchor="OP_SEQUENCE_IMPLEMENTATION" title="IMPLEMENTATI		e">
	ON">		<name>IMPLEMENTATION</name>
	<t>		<t>
	The server MUST maintain a mapping of session ID to client ID		The server <bcp14>MUST</bcp14> maintain a mapping of session ID to client
			ID
	in order to validate any operations that follow SEQUENCE		in order to validate any operations that follow SEQUENCE
	that take a stateid as an argument and/or result.		that take a stateid as an argument and/or result.
	</t>		</t>
	<t>		<t>
	If the client establishes a persistent session, then		If the client establishes a persistent session, then
	a SEQUENCE received after a server restart might encounter		a SEQUENCE received after a server restart might encounter
	requests performed and recorded in a persistent reply		requests performed and recorded in a persistent reply
	cache before the server restart. In this case, SEQUENCE		cache before the server restart. In this case, SEQUENCE
	will be processed successfully, while requests that		will be processed successfully, while requests that
	were not previously performed and recorded are rejected with		were not previously performed and recorded are rejected with
	NFS4ERR_DEADSESSION.		NFS4ERR_DEADSESSION.
	</t>		</t>
	<t>		<t>
	Depending on which of the operations within the COMPOUND were		Depending on which of the operations within the COMPOUND were
	successfully		successfully
	performed before the server restart, these operations will		performed before the server restart, these operations will
	also have replies sent from the server reply cache.		also have replies sent from the server reply cache.
	Note that when these operations establish locking state, it		Note that when these operations establish locking state, it
	is locking state that applies to the previous server instance		is locking state that applies to the previous server instance
	and to the previous client ID, even though the		and to the previous client ID, even though the
	server restart, which logically happened after these		server restart, which logically happened after these
	operations, eliminated that state. In the		operations, eliminated that state. In the
	case of a partially executed COMPOUND, processing may reach		case of a partially executed COMPOUND, processing may reach
	an operation not processed during the earlier server instance,		an operation not processed during the earlier server instance,
	making this operation a new one and not performable on the		making this operation a new one and not performable on the
	existing session. In this case, NFS4ERR_DEADSESSION will be		existing session. In this case, NFS4ERR_DEADSESSION will be
	returned from that operation.		returned from that operation.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_SET_SSV" numbered="true" toc="default">
	$ -->		<name>Operation 54: SET_SSV - Update SSV for a Client ID</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_SET_SSV_ARGUMENT" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_SET_SSV"		<sourcecode type="xdr"><![CDATA[
	title="Operation 54: SET_SSV - Update SSV for a Client ID" >
	<section toc="exclude" anchor="OP_SET_SSV_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct ssa_digest_input4 {		struct ssa_digest_input4 {
	SEQUENCE4args sdi_seqargs;		SEQUENCE4args sdi_seqargs;
	};		};
	struct SET_SSV4args {		struct SET_SSV4args {
	opaque ssa_ssv&lt;>;		opaque ssa_ssv<>;
	opaque ssa_digest&lt;>;		opaque ssa_digest<>;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_SET_SSV_RESULT" numbered="true">
	</figure>		<name>RESULT</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_SET_SSV_RESULT" title="RESULT">
	<figure>
	<artwork>
	struct ssr_digest_input4 {		struct ssr_digest_input4 {
	SEQUENCE4res sdi_seqres;		SEQUENCE4res sdi_seqres;
	};		};
	struct SET_SSV4resok {		struct SET_SSV4resok {
	opaque ssr_digest&lt;>;		opaque ssr_digest<>;
	};		};
	union SET_SSV4res switch (nfsstat4 ssr_status) {		union SET_SSV4res switch (nfsstat4 ssr_status) {
	case NFS4_OK:		case NFS4_OK:
	SET_SSV4resok ssr_resok4;		SET_SSV4resok ssr_resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_SET_SSV_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_SET_SSV_DESCRIPTION" title="DESCRIPTION">
	<t>
	This operation is used to update the		This operation is used to update the
	SSV for a client ID. Before SET_SSV is called the		SSV for a client ID. Before SET_SSV is called the
	first time on a client ID, the SSV is zero.		first time on a client ID, the SSV is zero.
	The SSV is the key used for the SSV GSS mechanism		The SSV is the key used for the SSV GSS mechanism
	(<xref target="ssv_mech" />)		(<xref target="ssv_mech" format="default"/>)
	</t>		</t>
	<t>		<t>
	SET_SSV MUST be preceded by a		SET_SSV <bcp14>MUST</bcp14> be preceded by a
	SEQUENCE operation in the same COMPOUND.		SEQUENCE operation in the same COMPOUND.
	It MUST NOT be used if the client		It <bcp14>MUST NOT</bcp14> be used if the client
	did not opt for SP4_SSV state protection when the		did not opt for SP4_SSV state protection when the
	client ID was created		client ID was created
	(see <xref target="OP_EXCHANGE_ID" />);		(see <xref target="OP_EXCHANGE_ID" format="default"/>);
	the server returns NFS4ERR_INVAL in that case.		the server returns NFS4ERR_INVAL in that case.
	</t>		</t>
	<t>		<t>
	The field ssa_digest is computed as the output of		The field ssa_digest is computed as the output of
	the HMAC (<xref target="RFC2104">RFC 2104</xref>) using the subkey derived		the HMAC (<xref target="RFC2104" format="default">RFC 2104</xref>) using t he subkey derived
	from the SSV4_SUBKEY_MIC_I2T and current SSV		from the SSV4_SUBKEY_MIC_I2T and current SSV
	as the key (see <xref target="ssv_mech" /> for a		as the key (see <xref target="ssv_mech" format="default"/> for a
	description of subkeys), and an XDR encoded value of data type ssa_digest_ input4.		description of subkeys), and an XDR encoded value of data type ssa_digest_ input4.
	The field sdi_seqargs is equal to the		The field sdi_seqargs is equal to the
	arguments of the SEQUENCE operation		arguments of the SEQUENCE operation
	for the COMPOUND procedure that		for the COMPOUND procedure that
	SET_SSV is within.		SET_SSV is within.
	</t>		</t>
	<t>		<t>
	The argument ssa_ssv		The argument ssa_ssv
	is XORed with the current SSV to produce		is XORed with the current SSV to produce
	the new SSV. The argument ssa_ssv SHOULD be generated randomly.		the new SSV. The argument ssa_ssv <bcp14>SHOULD</bcp14> be generated rando
	</t>		mly.
	<t>		</t>
			<t>
	In the response, ssr_digest is the output of the HMAC using the		In the response, ssr_digest is the output of the HMAC using the
	subkey derived from SSV4_SUBKEY_MIC_T2I and new SSV as the key,		subkey derived from SSV4_SUBKEY_MIC_T2I and new SSV as the key,
	and an XDR encoded value of data type ssr_digest_input4. The		and an XDR encoded value of data type ssr_digest_input4. The
	field sdi_seqres is equal to the results of the SEQUENCE		field sdi_seqres is equal to the results of the SEQUENCE
	operation for the COMPOUND procedure that SET_SSV is within.		operation for the COMPOUND procedure that SET_SSV is within.
	</t>		</t>
	<t>		<t>
	As noted in <xref target="OP_EXCHANGE_ID" />, the client and		As noted in <xref target="OP_EXCHANGE_ID" format="default"/>, the client a
			nd
	server can maintain multiple concurrent versions of the SSV.		server can maintain multiple concurrent versions of the SSV.
	The client and server each MUST maintain an internal		The client and server each <bcp14>MUST</bcp14> maintain an internal
	SSV version number, which is set to one the first time		SSV version number, which is set to one the first time
	SET_SSV executes on the server and the client		SET_SSV executes on the server and the client
	receives the first SET_SSV reply. Each subsequent		receives the first SET_SSV reply. Each subsequent
	SET_SSV increases the internal SSV version number by one. The		SET_SSV increases the internal SSV version number by one. The
	value of this version number corresponds to the smpt_ssv_seq,		value of this version number corresponds to the smpt_ssv_seq,
	smt_ssv_seq, sspt_ssv_seq, and ssct_ssv_seq fields of the		smt_ssv_seq, sspt_ssv_seq, and ssct_ssv_seq fields of the
	SSV GSS mechanism tokens (see <xref target="ssv_mech"/>).		SSV GSS mechanism tokens (see <xref target="ssv_mech" format="default"/>).
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_SET_SSV_IMPLEMENTATION" title="IMPLEMENTATIO		<section toc="exclude" anchor="OP_SET_SSV_IMPLEMENTATION" numbered="true
	N">		">
	<t>		<name>IMPLEMENTATION</name>
	When the server receives ssa_digest, it MUST verify the digest		<t>
			When the server receives ssa_digest, it <bcp14>MUST</bcp14> verify the dig
			est
	by computing the digest the same way the client did and		by computing the digest the same way the client did and
	comparing it with ssa_digest. If the server gets a different		comparing it with ssa_digest. If the server gets a different
	result, this is an error, NFS4ERR_BAD_SESSION_DIGEST.		result, this is an error, NFS4ERR_BAD_SESSION_DIGEST.
	This error might be the result of another SET_SSV from the		This error might be the result of another SET_SSV from the
	same client ID changing the SSV. If so, the client recovers		same client ID changing the SSV. If so, the client recovers
	by sending a SET_SSV operation again with a recomputed digest based on		by sending a SET_SSV operation again with a recomputed digest based on
	the subkey of the new SSV. If the transport connection is dropped after		the subkey of the new SSV. If the transport connection is dropped after
	the SET_SSV request is sent, but before the		the SET_SSV request is sent, but before the
	SET_SSV reply is received, then there are special considerations		SET_SSV reply is received, then there are special considerations
	for recovery if the client has no more connections associated		for recovery if the client has no more connections associated
	with sessions associated with the client ID of the SSV. See		with sessions associated with the client ID of the SSV. See
	<xref target="OP_BIND_CONN_TO_SESSION_IMPLEMENTATION"/>.		<xref target="OP_BIND_CONN_TO_SESSION_IMPLEMENTATION" format="default"/>.
	</t>		</t>
	<t>		<t>
	Clients SHOULD NOT send an ssa_ssv that is equal to a previous		Clients <bcp14>SHOULD NOT</bcp14> send an ssa_ssv that is equal to a previ
			ous
	ssa_ssv, nor equal to a previous or current SSV (including an ssa_ssv equa l to zero		ssa_ssv, nor equal to a previous or current SSV (including an ssa_ssv equa l to zero
	since the SSV is initialized to zero when the client ID is created).		since the SSV is initialized to zero when the client ID is created).
	</t>		</t>
	<t>		<t>
	Clients SHOULD send SET_SSV with RPCSEC_GSS privacy. Servers		Clients <bcp14>SHOULD</bcp14> send SET_SSV with RPCSEC_GSS privacy. Server
	MUST support RPCSEC_GSS with privacy for any COMPOUND that has {		s
			<bcp14>MUST</bcp14> support RPCSEC_GSS with privacy for any COMPOUND that
			has {
	SEQUENCE, SET_SSV }.		SEQUENCE, SET_SSV }.
	</t>		</t>
	<t>		<t>
	A client SHOULD NOT send SET_SSV with the SSV GSS		A client <bcp14>SHOULD NOT</bcp14> send SET_SSV with the SSV GSS
	mechanism's credential because the purpose of SET_SSV		mechanism's credential because the purpose of SET_SSV
	is to seed the SSV from non-SSV credentials. Instead,		is to seed the SSV from non-SSV credentials. Instead,
	SET_SSV SHOULD be sent with the credential of		SET_SSV <bcp14>SHOULD</bcp14> be sent with the credential of
	a user that is accessing the client ID for the		a user that is accessing the client ID for the
	first time		first time
	(<xref target="protect_state_change" />).		(<xref target="protect_state_change" format="default"/>).
	However, if the client does send SET_SSV with SSV		However, if the client does send SET_SSV with SSV
	credentials, the digest protecting the arguments		credentials, the digest protecting the arguments
	uses the value of the SSV before ssa_ssv is XORed in,		uses the value of the SSV before ssa_ssv is XORed in,
	and the digest protecting the results uses the value		and the digest protecting the results uses the value
	of the SSV after the ssa_ssv is XORed in.		of the SSV after the ssa_ssv is XORed in.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		<section anchor="OP_TEST_STATEID" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 55: TEST_STATEID - Test Stateids for Validity</name>
	$ -->		<section toc="exclude" anchor="OP_TEST_STATEID_ARGUMENT" numbered="true"
	<!-- Copyright (C) The IETF Trust (2007) -->		>
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_TEST_STATEID" title="Operation 55: TEST_STATEID - Test State		<sourcecode type="xdr"><![CDATA[
	ids for Validity" >
	<section toc="exclude" anchor="OP_TEST_STATEID_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct TEST_STATEID4args {		struct TEST_STATEID4args {
	stateid4 ts_stateids&lt;>;		stateid4 ts_stateids<>;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_TEST_STATEID_RESULT" numbered="true">
	</figure>		<name>RESULT</name>
	</section>		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_TEST_STATEID_RESULT" title="RESULT">
	<figure>
	<artwork>
	struct TEST_STATEID4resok {		struct TEST_STATEID4resok {
	nfsstat4 tsr_status_codes&lt;>;		nfsstat4 tsr_status_codes<>;
	};		};
	union TEST_STATEID4res switch (nfsstat4 tsr_status) {		union TEST_STATEID4res switch (nfsstat4 tsr_status) {
	case NFS4_OK:		case NFS4_OK:
	TEST_STATEID4resok tsr_resok4;		TEST_STATEID4resok tsr_resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_TEST_STATEID4_DESCRIPTION" numbered="t
	</figure>		rue">
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_TEST_STATEID4_DESCRIPTION" title="DESCRIPTIO		<t>
	N">
	<t>
	The TEST_STATEID operation is used to check the validity of		The TEST_STATEID operation is used to check the validity of
	a set of stateids. It can be used at any time, but the client		a set of stateids. It can be used at any time, but the client
	should definitely use it when it		should definitely use it when it
	receives an indication that one or more of its stateids have been		receives an indication that one or more of its stateids have been
	invalidated due to lock revocation. This occurs when the SEQUENCE		invalidated due to lock revocation. This occurs when the SEQUENCE
	operation returns with one of the following sr_status_flags set:		operation returns with one of the following sr_status_flags set:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED		SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED
	</t>		</li>
	<t>		<li>
	SEQ4_STATUS_EXPIRED_ADMIN_STATE_REVOKED		SEQ4_STATUS_EXPIRED_ADMIN_STATE_REVOKED
	</t>		</li>
	<t>		<li>
	SEQ4_STATUS_EXPIRED_RECALLABLE_STATE_REVOKED		SEQ4_STATUS_EXPIRED_RECALLABLE_STATE_REVOKED
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The client can use TEST_STATEID one or more times to test the		The client can use TEST_STATEID one or more times to test the
	validity of its stateids. Each use of TEST_STATEID allows a large		validity of its stateids. Each use of TEST_STATEID allows a large
	set of such stateids to be tested and avoids problems with earlier		set of such stateids to be tested and avoids problems with earlier
	stateids in a COMPOUND request from interfering with the checking of		stateids in a COMPOUND request from interfering with the checking of
	subsequent stateids, as would happen if individual stateids were		subsequent stateids, as would happen if individual stateids were
	tested by a series of corresponding by operations in a COMPOUND		tested by a series of corresponding by operations in a COMPOUND
	request.		request.
	</t>		</t>
	<t>		<t>
	For each stateid, the server returns the status code that		For each stateid, the server returns the status code that
	would be returned if that stateid were to be used in normal		would be returned if that stateid were to be used in normal
	operation. Returning such a status indication is not an		operation. Returning such a status indication is not an
	error and does not cause COMPOUND processing to terminate. Checks		error and does not cause COMPOUND processing to terminate. Checks
	for the validity of the stateid proceed as they would for		for the validity of the stateid proceed as they would for
	normal operations with a number of exceptions:		normal operations with a number of exceptions:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	There is no check for the type of stateid object, as would be		There is no check for the type of stateid object, as would be
	the case for normal use of a stateid.		the case for normal use of a stateid.
	</t>		</li>
	<t>		<li>
	There is no reference to the current filehandle.		There is no reference to the current filehandle.
	</t>		</li>
	<t>		<li>
	Special stateids are always considered invalid (they result		Special stateids are always considered invalid (they result
	in the error code NFS4ERR_BAD_STATEID).		in the error code NFS4ERR_BAD_STATEID).
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	All stateids are interpreted as being associated with the client		All stateids are interpreted as being associated with the client
	for the current session. Any possible association with a previous		for the current session. Any possible association with a previous
	instance of the client (as stale stateids) is not considered.		instance of the client (as stale stateids) is not considered.
	</t>		</t>
	<t>		<t>
	The valid status values in the returned status_code array		The valid status values in the returned status_code array
	are NFS4ERR_OK, NFS4ERR_BAD_STATEID, NFS4ERR_OLD_STATEID,		are NFS4ERR_OK, NFS4ERR_BAD_STATEID, NFS4ERR_OLD_STATEID,
	NFS4ERR_EXPIRED, NFS4ERR_ADMIN_REVOKED, and NFS4ERR_DELEG_REVOKED.		NFS4ERR_EXPIRED, NFS4ERR_ADMIN_REVOKED, and NFS4ERR_DELEG_REVOKED.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_TEST_STATEID_IMPLEMENTATION" title="IMPLEMEN		<section toc="exclude" anchor="OP_TEST_STATEID_IMPLEMENTATION" numbered=
	TATION">		"true">
	<t>		<name>IMPLEMENTATION</name>
	See Sections <xref target="stateid_structure" format="counter" /> and		<t>
	<xref target="stateid_lifetime" format="counter" />		See Sections <xref target="stateid_structure" format="counter"/> and
			<xref target="stateid_lifetime" format="counter"/>
	for a discussion of stateid structure, lifetime, and validation.		for a discussion of stateid structure, lifetime, and validation.
	</t>		</t>
	</section>		</section>
	</section>		</section>
			<section anchor="OP_WANT_DELEGATION" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 56: WANT_DELEGATION - Request Delegation</name>
	$ -->		<section toc="exclude" anchor="OP_WANT_DELEGATION_ARGUMENT" numbered="tr
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		ue">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_WANT_DELEGATION"		<sourcecode type="xdr"><![CDATA[
	title="Operation 56: WANT_DELEGATION - Request Delegation" >
	<section toc="exclude" anchor="OP_WANT_DELEGATION_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	union deleg_claim4 switch (open_claim_type4 dc_claim) {		union deleg_claim4 switch (open_claim_type4 dc_claim) {
	/*		/*
	* No special rights to object. Ordinary delegation		* No special rights to object. Ordinary delegation
	* request of the specified object. Object identified		* request of the specified object. Object identified
	* by filehandle.		* by filehandle.
	*/		*/
	case CLAIM_FH: /* new to v4.1 */		case CLAIM_FH: /* new to v4.1 */
	/* CURRENT_FH: object being delegated */		/* CURRENT_FH: object being delegated */
	void;		void;
	skipping to change at line 39699 ¶		skipping to change at line 39643 ¶
	* Used during server reclaim grace period.		* Used during server reclaim grace period.
	*/		*/
	case CLAIM_PREVIOUS:		case CLAIM_PREVIOUS:
	/* CURRENT_FH: object being reclaimed */		/* CURRENT_FH: object being reclaimed */
	open_delegation_type4 dc_delegate_type;		open_delegation_type4 dc_delegate_type;
	};		};
	struct WANT_DELEGATION4args {		struct WANT_DELEGATION4args {
	uint32_t wda_want;		uint32_t wda_want;
	deleg_claim4 wda_claim;		deleg_claim4 wda_claim;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_WANT_DELEGATION_RESULT" numbered="true
	</figure>		">
	</section>		<name>RESULT</name>
	<section toc="exclude" anchor="OP_WANT_DELEGATION_RESULT" title="RESULT">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	union WANT_DELEGATION4res switch (nfsstat4 wdr_status) {		union WANT_DELEGATION4res switch (nfsstat4 wdr_status) {
	case NFS4_OK:		case NFS4_OK:
	open_delegation4 wdr_resok4;		open_delegation4 wdr_resok4;
	default:		default:
	void;		void;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_WANT_DELEGATION_DESCRIPTION" numbered=
	</figure>		"true">
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_WANT_DELEGATION_DESCRIPTION" title="DESCRIPT		<t>
	ION">
	<t>
	Where this description mandates the return of a specific error		Where this description mandates the return of a specific error
	code for a specific condition, and where multiple conditions		code for a specific condition, and where multiple conditions
	apply, the server MAY return any of the mandated error codes.		apply, the server <bcp14>MAY</bcp14> return any of the mandated error code
	</t>		s.
	<t>		</t>
			<t>
	This operation allows a client to:		This operation allows a client to:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	Get a delegation on all types		Get a delegation on all types
	of files except directories.		of files except directories.
	</t>		</li>
	<t>		<li>
	Register a "want" for a delegation for the		Register a "want" for a delegation for the
	specified file object, and be notified via a		specified file object, and be notified via a
	callback when the delegation is available. The		callback when the delegation is available. The
	server MAY support notifications of availability		server <bcp14>MAY</bcp14> support notifications of availability
	via callbacks. If the server does not support		via callbacks. If the server does not support
	registration of wants, it MUST NOT return		registration of wants, it <bcp14>MUST NOT</bcp14> return
	an error to indicate that, and instead MUST		an error to indicate that, and instead <bcp14>MUST</bcp14>
	return with ond_why set to WND4_CONTENTION or		return with ond_why set to WND4_CONTENTION or
	WND4_RESOURCE and ond_server_will_push_deleg or		WND4_RESOURCE and ond_server_will_push_deleg or
	ond_server_will_signal_avail set to FALSE. When the		ond_server_will_signal_avail set to FALSE. When the
	server indicates that it will notify the client		server indicates that it will notify the client
	by means of a callback, it will either provide		by means of a callback, it will either provide
	the delegation using a CB_PUSH_DELEG operation or		the delegation using a CB_PUSH_DELEG operation or
	cancel its promise by sending a CB_WANTS_CANCELLED		cancel its promise by sending a CB_WANTS_CANCELLED
	operation.		operation.
	</t>		</li>
	<t>		<li>
	Cancel a want for a delegation.		Cancel a want for a delegation.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		The client <bcp14>SHOULD NOT</bcp14> set OPEN4_SHARE_ACCESS_READ and <bcp1
	The client SHOULD NOT set OPEN4_SHARE_ACCESS_READ and SHOULD NOT		4>SHOULD NOT</bcp14>
	set OPEN4_SHARE_ACCESS_WRITE in wda_want. If it does, the server		set OPEN4_SHARE_ACCESS_WRITE in wda_want. If it does, the server
	MUST ignore them.		<bcp14>MUST</bcp14> ignore them.
	</t>		</t>
	<t>		<t>
	The meanings of the following flags in wda_want are the same as		The meanings of the following flags in wda_want are the same as
	they are in OPEN, except as noted below.		they are in OPEN, except as noted below.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	OPEN4_SHARE_ACCESS_WANT_READ_DELEG		OPEN4_SHARE_ACCESS_WANT_READ_DELEG
	</t>		</li>
	<t>		<li>
	OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG		OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG
	</t>		</li>
	<t>		<li>
	OPEN4_SHARE_ACCESS_WANT_ANY_DELEG		OPEN4_SHARE_ACCESS_WANT_ANY_DELEG
	</t>		</li>
	<t>		<li>
	OPEN4_SHARE_ACCESS_WANT_NO_DELEG. Unlike the OPEN operation,		OPEN4_SHARE_ACCESS_WANT_NO_DELEG. Unlike the OPEN operation,
	this flag SHOULD NOT be set by the client in the arguments to		this flag <bcp14>SHOULD NOT</bcp14> be set by the client in the argume
	WANT_DELEGATION, and MUST be ignored by the server.		nts to
			WANT_DELEGATION, and <bcp14>MUST</bcp14> be ignored by the server.
	</t>		</li>
	<t>		<li>
	OPEN4_SHARE_ACCESS_WANT_CANCEL		OPEN4_SHARE_ACCESS_WANT_CANCEL
	</t>		</li>
	<t>		<li>
	OPEN4_SHARE_ACCESS_WANT_SIGNAL_DELEG_WHEN_RESRC_AVAIL		OPEN4_SHARE_ACCESS_WANT_SIGNAL_DELEG_WHEN_RESRC_AVAIL
	</t>		</li>
	<t>		<li>
	OPEN4_SHARE_ACCESS_WANT_PUSH_DELEG_WHEN_UNCONTENDED		OPEN4_SHARE_ACCESS_WANT_PUSH_DELEG_WHEN_UNCONTENDED
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	The handling of the above flags in WANT_DELEGATION is the same		The handling of the above flags in WANT_DELEGATION is the same
	as in OPEN. Information about the delegation and/or the		as in OPEN. Information about the delegation and/or the
	promises the server is making regarding future callbacks are		promises the server is making regarding future callbacks are
	the same as those described in the open_delegation4 structure.		the same as those described in the open_delegation4 structure.
	</t>		</t>
	<t>		<t>
	The successful results of WANT_DELEGATION are of data type		The successful results of WANT_DELEGATION are of data type
	open_delegation4, which is the same data type as the "delegation"		open_delegation4, which is the same data type as the "delegation"
	field in the results of the OPEN operation		field in the results of the OPEN operation
	(see <xref target="OP_OPEN_DESCRIPTION" />).		(see <xref target="OP_OPEN_DESCRIPTION" format="default"/>).
	The server constructs wdr_resok4 the same way it constructs		The server constructs wdr_resok4 the same way it constructs
	OPEN's "delegation" with one difference:		OPEN's "delegation" with one difference:
	WANT_DELEGATION MUST NOT return a delegation type of		WANT_DELEGATION <bcp14>MUST NOT</bcp14> return a delegation type of
	OPEN_DELEGATE_NONE.		OPEN_DELEGATE_NONE.
	</t>		</t>
	<t>		<t>
	If ((wda_want &amp; OPEN4_SHARE_ACCESS_WANT_DELEG_MASK) &amp;		If ((wda_want &amp; OPEN4_SHARE_ACCESS_WANT_DELEG_MASK) &amp;
	~OPEN4_SHARE_ACCESS_WANT_NO_DELEG) is zero,		~OPEN4_SHARE_ACCESS_WANT_NO_DELEG) is zero,
	then the client is indicating no		then the client is indicating no
	explicit desire or non-desire for a delegation and the server MUST return		explicit desire or non-desire for a delegation and the server <bcp14>MUST< /bcp14> return
	NFS4ERR_INVAL.		NFS4ERR_INVAL.
	</t>		</t>
	<t>		<t>
	The client uses the		The client uses the
	OPEN4_SHARE_ACCESS_WANT_CANCEL		OPEN4_SHARE_ACCESS_WANT_CANCEL
	flag in the WANT_DELEGATION		flag in the WANT_DELEGATION
	operation to cancel a previously requested want for a delegation.		operation to cancel a previously requested want for a delegation.
	Note that if the server is in the process of sending the		Note that if the server is in the process of sending the
	delegation (via CB_PUSH_DELEG) at the time the client sends		delegation (via CB_PUSH_DELEG) at the time the client sends
	a cancellation of the want, the delegation might still be pushed		a cancellation of the want, the delegation might still be pushed
	to the client.		to the client.
	</t>		</t>
	<t>		<t>
	If WANT_DELEGATION fails to return a delegation, and		If WANT_DELEGATION fails to return a delegation, and
	the server returns NFS4_OK, the server MUST set the		the server returns NFS4_OK, the server <bcp14>MUST</bcp14> set the
	delegation type to OPEN4_DELEGATE_NONE_EXT, and set		delegation type to OPEN4_DELEGATE_NONE_EXT, and set
	od_whynone, as described in <xref target="OP_OPEN"		od_whynone, as described in <xref target="OP_OPEN" format="default"/>. Wri
	/>. Write delegations are not available for		te delegations are not available for
	file types that are not writable. This includes		file types that are not writable. This includes
	file objects of types NF4BLK, NF4CHR, NF4LNK,		file objects of types NF4BLK, NF4CHR, NF4LNK,
	NF4SOCK, and NF4FIFO. If the client requests		NF4SOCK, and NF4FIFO. If the client requests
	OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG without		OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG without
	OPEN4_SHARE_ACCESS_WANT_READ_DELEG on an object with		OPEN4_SHARE_ACCESS_WANT_READ_DELEG on an object with
	one of the aforementioned file types, the server must		one of the aforementioned file types, the server must
	set wdr_resok4.od_whynone.ond_why to		set wdr_resok4.od_whynone.ond_why to
	WND4_WRITE_DELEG_NOT_SUPP_FTYPE.		WND4_WRITE_DELEG_NOT_SUPP_FTYPE.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_WANT_DELEGATION_IMPLEMENTATION" title="IMPLE		<section toc="exclude" anchor="OP_WANT_DELEGATION_IMPLEMENTATION" number
	MENTATION">		ed="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	A request for a conflicting delegation is not normally intended to trigger		A request for a conflicting delegation is not normally intended to trigger
	the recall of the existing delegation. Servers may choose to treat		the recall of the existing delegation. Servers may choose to treat
	some clients as having higher priority such that their wants will		some clients as having higher priority such that their wants will
	trigger recall of an existing delegation, although that is expected		trigger recall of an existing delegation, although that is expected
	to be an unusual situation.		to be an unusual situation.
	</t>		</t>
	<t>		<t>
	Servers will generally recall delegations assigned by WANT_DELEGATION		Servers will generally recall delegations assigned by WANT_DELEGATION
	on the same basis as those assigned by OPEN. CB_RECALL will generally		on the same basis as those assigned by OPEN. CB_RECALL will generally
	be done only when other clients perform operations inconsistent with		be done only when other clients perform operations inconsistent with
	the delegation. The normal response to aging of delegations is to use		the delegation. The normal response to aging of delegations is to use
	CB_RECALL_ANY, in order to give the client the opportunity to keep		CB_RECALL_ANY, in order to give the client the opportunity to keep
	the delegations most useful from its point of view.		the delegations most useful from its point of view.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		<section anchor="OP_DESTROY_CLIENTID" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 57: DESTROY_CLIENTID - Destroy a Client ID</name>
	$ -->		<section toc="exclude" anchor="OP_DESTROY_CLIENTID_ARGUMENT" numbered="t
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		rue">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_DESTROY_CLIENTID" title="Operation 57: DESTROY_CLIENTID - De		<sourcecode type="xdr"><![CDATA[
	stroy a Client ID" >
	<section toc="exclude" anchor="OP_DESTROY_CLIENTID_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct DESTROY_CLIENTID4args {		struct DESTROY_CLIENTID4args {
	clientid4 dca_clientid;		clientid4 dca_clientid;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_DESTROY_CLIENTID_RESULT" numbered="tru
	</figure>		e">
	</section>		<name>RESULT</name>
	<section toc="exclude" anchor="OP_DESTROY_CLIENTID_RESULT" title="RESULT">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct DESTROY_CLIENTID4res {		struct DESTROY_CLIENTID4res {
	nfsstat4 dcr_status;		nfsstat4 dcr_status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_DESTROY_CLIENTID_DESCRIPTION" numbered
	</figure>		="true">
	</section>		<name>DESCRIPTION</name>
	<section toc="exclude" anchor="OP_DESTROY_CLIENTID_DESCRIPTION" title="DESCRIP		<t>
	TION">
	<t>
	The DESTROY_CLIENTID operation destroys the		The DESTROY_CLIENTID operation destroys the
	client ID. If there are sessions (both idle and		client ID. If there are sessions (both idle and
	non-idle), opens, locks, delegations, layouts,		non-idle), opens, locks, delegations, layouts,
	and/or wants (<xref target="OP_WANT_DELEGATION" />)		and/or wants (<xref target="OP_WANT_DELEGATION" format="default"/>)
	associated with the unexpired lease of the client		associated with the unexpired lease of the client
	ID, the server MUST return NFS4ERR_CLIENTID_BUSY.		ID, the server <bcp14>MUST</bcp14> return NFS4ERR_CLIENTID_BUSY.
	DESTROY_CLIENTID MAY be preceded with a SEQUENCE		DESTROY_CLIENTID <bcp14>MAY</bcp14> be preceded with a SEQUENCE
	operation as long as the client ID derived from the		operation as long as the client ID derived from the
	session ID of SEQUENCE is not the same as the client		session ID of SEQUENCE is not the same as the client
	ID to be destroyed. If the client IDs are the same,		ID to be destroyed. If the client IDs are the same,
	then the server MUST return NFS4ERR_CLIENTID_BUSY.		then the server <bcp14>MUST</bcp14> return NFS4ERR_CLIENTID_BUSY.
	</t>
	<t>		</t>
			<t>
	If DESTROY_CLIENTID is not prefixed by SEQUENCE,		If DESTROY_CLIENTID is not prefixed by SEQUENCE,
	it MUST be the only operation in the COMPOUND		it <bcp14>MUST</bcp14> be the only operation in the COMPOUND
	request (otherwise, the server MUST return		request (otherwise, the server <bcp14>MUST</bcp14> return
	NFS4ERR_NOT_ONLY_OP). If the operation is sent		NFS4ERR_NOT_ONLY_OP). If the operation is sent
	without a SEQUENCE preceding it, a client that		without a SEQUENCE preceding it, a client that
	retransmits the request may receive an error in		retransmits the request may receive an error in
	response, because the original request might have		response, because the original request might have
	been successfully executed.		been successfully executed.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_DESTROY_CLIENTID_IMPLEMENTATION" title="IMPL		<section toc="exclude" anchor="OP_DESTROY_CLIENTID_IMPLEMENTATION" numbe
	EMENTATION">		red="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	DESTROY_CLIENTID allows a server to immediately		DESTROY_CLIENTID allows a server to immediately
	reclaim the resources consumed by an unused client		reclaim the resources consumed by an unused client
	ID, and also to forget that it ever generated the		ID, and also to forget that it ever generated the
	client ID. By forgetting that it ever generated the client		client ID. By forgetting that it ever generated the client
	ID, the server can safely reuse the client ID on a		ID, the server can safely reuse the client ID on a
	future EXCHANGE_ID operation.		future EXCHANGE_ID operation.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_RECLAIM_COMPLETE" numbered="true" toc="default">
	$ -->		<name>Operation 58: RECLAIM_COMPLETE - Indicates Reclaims Finished</name
	<!-- Copyright (C) The IETF Trust (2007) -->		>
	<!-- Copyright (C) The Internet Society (2006) -->		<section toc="exclude" anchor="OP_RECLAIM_COMPLETE_ARGUMENT" numbered="t
	<section title="Operation 58: RECLAIM_COMPLETE - Indicates Reclaims Finished		rue">
	"		<name>ARGUMENT</name>
	anchor="OP_RECLAIM_COMPLETE">		<sourcecode type="xdr"><![CDATA[
	<section title="ARGUMENT"
	toc="exclude"
	anchor="OP_RECLAIM_COMPLETE_ARGUMENT">
	<figure>
	<artwork>
	&lt;CODE BEGINS&gt;
	struct RECLAIM_COMPLETE4args {		struct RECLAIM_COMPLETE4args {
	/*		/*
	* If rca_one_fs TRUE,		* If rca_one_fs TRUE,
	*		*
	* CURRENT_FH: object in		* CURRENT_FH: object in
	* file system reclaim is		* file system reclaim is
	* complete for.		* complete for.
	*/		*/
	bool rca_one_fs;		bool rca_one_fs;
	};		};
			]]></sourcecode>
	&lt;CODE ENDS&gt;		</section>
	</artwork>		<section toc="exclude" anchor="OP_RECLAIM_COMPLETE_RESULTS" numbered="tr
	</figure>		ue">
	</section>		<name>RESULTS</name>
			<sourcecode type="xdr"><![CDATA[
	<section title="RESULTS"
	toc="exclude"
	anchor="OP_RECLAIM_COMPLETE_RESULTS">
	<figure>
	<artwork>
	&lt;CODE BEGINS&gt;
	struct RECLAIM_COMPLETE4res {		struct RECLAIM_COMPLETE4res {
	nfsstat4 rcr_status;		nfsstat4 rcr_status;
	};		};
			]]></sourcecode>
	&lt;CODE ENDS&gt;		</section>
	</artwork>		<section toc="exclude" anchor="OP_RECLAIM_COMPLETE_DESCRIPTION" numbered
	</figure>		="true">
	</section>		<name>DESCRIPTION</name>
			<t>
	<section title="DESCRIPTION"
	toc="exclude"
	anchor="OP_RECLAIM_COMPLETE_DESCRIPTION">
	<t>
	A RECLAIM_COMPLETE operation is used to indicate that the client		A RECLAIM_COMPLETE operation is used to indicate that the client
	has reclaimed all of the locking state that it will recover using		has reclaimed all of the locking state that it will recover using
	reclaim,		reclaim,
	when it is recovering state due to either a server restart or the		when it is recovering state due to either a server restart or the
	migration of a file system to another server. There are two types		migration of a file system to another server. There are two types
	of RECLAIM_COMPLETE operations:		of RECLAIM_COMPLETE operations:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	When rca_one_fs is FALSE, a global RECLAIM_COMPLETE is being		When rca_one_fs is FALSE, a global RECLAIM_COMPLETE is being
	done. This indicates that recovery of all		done. This indicates that recovery of all
	locks that the client held on the previous server instance		locks that the client held on the previous server instance
	has been completed. The current filehandle need not be set in		has been completed. The current filehandle need not be set in
	this case.		this case.
	</t>		</li>
	<t>		<li>
	When rca_one_fs is TRUE, a file system-specific RECLAIM_COMPLETE		When rca_one_fs is TRUE, a file system-specific RECLAIM_COMPLETE
	is being done. This indicates that recovery of locks		is being done. This indicates that recovery of locks
	for a single fs (the one designated by the current filehandle)		for a single fs (the one designated by the current filehandle)
	due to the migration of the file system has been completed. Presence		due to the migration of the file system has been completed. Presence
	of a current filehandle is required when rca_one_fs is set to TRUE.		of a current filehandle is required when rca_one_fs is set to TRUE.
	When the current filehandle designates a filehandle in a file system		When the current filehandle designates a filehandle in a file system
	not in the process of migration, the operation returns NFS4_OK and		not in the process of migration, the operation returns NFS4_OK and
	is otherwise ignored.		is otherwise ignored.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Once a RECLAIM_COMPLETE is done, there can be no further		Once a RECLAIM_COMPLETE is done, there can be no further
	reclaim operations for locks whose scope is defined as having		reclaim operations for locks whose scope is defined as having
	completed recovery. Once the client sends RECLAIM_COMPLETE,		completed recovery. Once the client sends RECLAIM_COMPLETE,
	the server will not allow the client to do		the server will not allow the client to do
	subsequent reclaims of locking state for that scope		subsequent reclaims of locking state for that scope
	and, if these are attempted, will return NFS4ERR_NO_GRACE.		and, if these are attempted, will return NFS4ERR_NO_GRACE.
	</t>		</t>
	<t>		<t>
	Whenever a client establishes a new client ID and before it does		Whenever a client establishes a new client ID and before it does
	the first non-reclaim operation that obtains a lock, it MUST send a		the first non-reclaim operation that obtains a lock, it <bcp14>MUST</bcp14 > send a
	RECLAIM_COMPLETE with rca_one_fs set to FALSE, even if there		RECLAIM_COMPLETE with rca_one_fs set to FALSE, even if there
	are no locks to		are no locks to
	reclaim. If non-reclaim		reclaim. If non-reclaim
	locking operations are done before the RECLAIM_COMPLETE, an NFS4ERR_GRACE		locking operations are done before the RECLAIM_COMPLETE, an NFS4ERR_GRACE
	error will be returned.		error will be returned.
	</t>		</t>
	<t>		<t>
	Similarly, when the client accesses a migrated file system on a new		Similarly, when the client accesses a migrated file system on a new
	server, before it sends the first non-reclaim operation that		server, before it sends the first non-reclaim operation that
	obtains a lock on this new server, it MUST send a RECLAIM_COMPLETE		obtains a lock on this new server, it <bcp14>MUST</bcp14> send a RECLAIM_C OMPLETE
	with rca_one_fs set to TRUE and current filehandle within that file system ,		with rca_one_fs set to TRUE and current filehandle within that file system ,
	even if there are no locks to reclaim. If non-reclaim locking		even if there are no locks to reclaim. If non-reclaim locking
	operations are done on that file system before the		operations are done on that file system before the
	RECLAIM_COMPLETE, an NFS4ERR_GRACE error will be returned.		RECLAIM_COMPLETE, an NFS4ERR_GRACE error will be returned.
	</t>		</t>
	<t>		<t>
	It should be noted that there are situations in which a client needs		It should be noted that there are situations in which a client needs
	to issue both forms of RECLAIM_COMPLETE. An example is an instance		to issue both forms of RECLAIM_COMPLETE. An example is an instance
	of file system migration in which the file system is migrated to a		of file system migration in which the file system is migrated to a
	server for which the client has no clientid. As a result, the client		server for which the client has no clientid. As a result, the client
	needs to obtain a clientid from the server (incurring the responsibility		needs to obtain a clientid from the server (incurring the responsibility
	to do RECLAIM_COMPLETE with rca_one_fs set to FALSE) as well as		to do RECLAIM_COMPLETE with rca_one_fs set to FALSE) as well as
	RECLAIM_COMPLETE with rca_one_fs set to TRUE to complete the per-fs		RECLAIM_COMPLETE with rca_one_fs set to TRUE to complete the per-fs
	grace period associated with the file system migration. These two		grace period associated with the file system migration. These two
	may be done in any order as long as all necessary lock reclaims		may be done in any order as long as all necessary lock reclaims
	have been done before		have been done before
	issuing either of them.		issuing either of them.
	</t>		</t>
	<t>		<t>
	Any locks not reclaimed at the point at which RECLAIM_COMPLETE		Any locks not reclaimed at the point at which RECLAIM_COMPLETE
	is done become non-reclaimable. The client MUST NOT attempt		is done become non-reclaimable. The client <bcp14>MUST NOT</bcp14> attemp t
	to reclaim them, either during		to reclaim them, either during
	the current server instance or in any subsequent		the current server instance or in any subsequent
	server instance, or on another server to which responsibility		server instance, or on another server to which responsibility
	for that file system is transferred. If the client were to do so,		for that file system is transferred. If the client were to do so,
	it would be		it would be
	violating the protocol by representing itself as owning locks		violating the protocol by representing itself as owning locks
	that it does not own, and so has no right to reclaim. See		that it does not own, and so has no right to reclaim. See
	Section 8.4.3 of <xref target="RFC5661"/> for a		<xref target="RFC5661" sectionFormat="of" section="8.4.3"/> for a
	discussion of edge conditions related to lock reclaim.		discussion of edge conditions related to lock reclaim.
	</t>		</t>
	<t>		<t>
	By sending a RECLAIM_COMPLETE, the client indicates readiness		By sending a RECLAIM_COMPLETE, the client indicates readiness
	to proceed to do normal non-reclaim locking operations. The client		to proceed to do normal non-reclaim locking operations. The client
	should be aware that such operations may temporarily result in		should be aware that such operations may temporarily result in
	NFS4ERR_GRACE errors until the server is ready to terminate its		NFS4ERR_GRACE errors until the server is ready to terminate its
	grace period.		grace period.
	</t>		</t>
	</section>		</section>
	<section title="IMPLEMENTATION"		<section toc="exclude" anchor="OP_RECLAIM_COMPLETE_IMPLEMENTATION" numbe
	toc="exclude"		red="true">
	anchor="OP_RECLAIM_COMPLETE_IMPLEMENTATION">		<name>IMPLEMENTATION</name>
	<t>		<t>
	Servers will typically use the information as to when reclaim		Servers will typically use the information as to when reclaim
	activity is complete to reduce the length of the grace period.		activity is complete to reduce the length of the grace period.
	When the server maintains in persistent storage		When the server maintains in persistent storage
	a list of clients that might have had locks,		a list of clients that might have had locks,
	it is able to use the fact that		it is able to use the fact that
	all such clients have done a RECLAIM_COMPLETE to terminate the		all such clients have done a RECLAIM_COMPLETE to terminate the
	grace period and begin normal operations (i.e., grant requests		grace period and begin normal operations (i.e., grant requests
	for new locks) sooner than it might otherwise.		for new locks) sooner than it might otherwise.
	</t>		</t>
	<t>		<t>
	Latency can be minimized by doing a RECLAIM_COMPLETE as part of		Latency can be minimized by doing a RECLAIM_COMPLETE as part of
	the COMPOUND request in which the last lock-reclaiming operation		the COMPOUND request in which the last lock-reclaiming operation
	is done. When there are no reclaims to be done, RECLAIM_COMPLETE		is done. When there are no reclaims to be done, RECLAIM_COMPLETE
	should be done immediately in order to allow the grace period		should be done immediately in order to allow the grace period
	to end as soon as possible.		to end as soon as possible.
	</t>		</t>
	<t>		<t>
	RECLAIM_COMPLETE should only be done once for each server instance		RECLAIM_COMPLETE should only be done once for each server instance
	or occasion of the transition of a file system.		or occasion of the transition of a file system.
	If it is done a second time, the error NFS4ERR_COMPLETE_ALREADY will		If it is done a second time, the error NFS4ERR_COMPLETE_ALREADY will
	result. Note that because of the session feature's retry protection,		result. Note that because of the session feature's retry protection,
	retries of COMPOUND		retries of COMPOUND
	requests containing RECLAIM_COMPLETE operation will not result		requests containing RECLAIM_COMPLETE operation will not result
	in this error.		in this error.
	</t>		</t>
	<t>		<t>
	When a RECLAIM_COMPLETE is sent, the client effectively acknowledges		When a RECLAIM_COMPLETE is sent, the client effectively acknowledges
	any locks not yet reclaimed as lost. This allows the server to		any locks not yet reclaimed as lost. This allows the server to
	re-enable the client to recover locks if the occurrence of edge		re-enable the client to recover locks if the occurrence of edge
	conditions, as described in		conditions, as described in
	<xref target="network_partitions_and_recovery"/>,		<xref target="network_partitions_and_recovery" format="default"/>,
	had caused the server to disable the client's ability to		had caused the server to disable the client's ability to
	recover locks.		recover locks.
	</t>		</t>
	<t>		<t>
	Because previous descriptions of RECLAIM_COMPLETE were not		Because previous descriptions of RECLAIM_COMPLETE were not
	sufficiently explicit about the circumstances in which use of		sufficiently explicit about the circumstances in which use of
	RECLAIM_COMPLETE with rca_one_fs set to TRUE was appropriate,		RECLAIM_COMPLETE with rca_one_fs set to TRUE was appropriate,
	there have been cases which it has been misused by clients who		there have been cases in which it has been misused by clients who
	have issued RECLAIM_COMPLETE with rca_one_fs set to TRUE when it		have issued RECLAIM_COMPLETE with rca_one_fs set to TRUE when it
	should have not been. There have also been		should have not been. There have also been
	cases in which servers have, in various ways, not responded to		cases in which servers have, in various ways, not responded to
	such misuse as described above, either ignoring the rca_one_fs		such misuse as described above, either ignoring the rca_one_fs
	setting (treating the operation as a global RECLAIM_COMPLETE) or		setting (treating the operation as a global RECLAIM_COMPLETE) or
	ignoring the entire operation.		ignoring the entire operation.
	</t>		</t>
	<t>		<t>
	While clients SHOULD NOT misuse		While clients <bcp14>SHOULD NOT</bcp14> misuse
	this feature and servers SHOULD respond to such misuse as described		this feature, and servers <bcp14>SHOULD</bcp14> respond to such misuse as
	above, implementers need to be aware of the following considerations		described
	as they make necessary tradeoffs between interoperability with		above, implementors need to be aware of the following considerations
			as they make necessary trade-offs between interoperability with
	existing implementations and proper support for facilities to		existing implementations and proper support for facilities to
	allow lock recovery in the event of file system migration.		allow lock recovery in the event of file system migration.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	When servers have no support for becoming the destination server		When servers have no support for becoming the destination server
	of a file system subject to migration, there is no possibility of		of a file system subject to migration, there is no possibility of
	a per-fs RECLAIM_COMPLETE being done legitimately and occurrences of it		a per-fs RECLAIM_COMPLETE being done legitimately, and occurrences of it
	SHOULD be ignored. However, the negative consequences of accepting		<bcp14>SHOULD</bcp14> be ignored. However, the negative consequences of
			accepting
	such mistaken use are quite limited as long as the client does		such mistaken use are quite limited as long as the client does
	not issue it		not issue it
	before all necessary reclaims are done.		before all necessary reclaims are done.
	</t>		</li>
	<t>		<li>
	When a server might become the destination for a file system being		When a server might become the destination for a file system being
	migrated, inappropriate use of per-fs RECLAIM_COMPLETE is more		migrated, inappropriate use of per-fs RECLAIM_COMPLETE is more
	concerning. In the case in which the file system designated is not		concerning. In the case in which the file system designated is not
	within a per-fs grace period, the per-fs RECLAIM_COMPLETE SHOULD		within a per-fs grace period, the per-fs RECLAIM_COMPLETE <bcp14>SHOULD</ bcp14>
	be ignored, with the		be ignored, with the
	negative consequences of accepting it being limited, as in the		negative consequences of accepting it being limited, as in the
	case in which migration is not supported. However, if the server		case in which migration is not supported. However, if the server
	encounters a file system undergoing migration, the operation		encounters a file system undergoing migration, the operation
	cannot be accepted		cannot be accepted
	as if it were a global RECLAIM_COMPLETE without invalidating its		as if it were a global RECLAIM_COMPLETE without invalidating its
	intended use.		intended use.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="OP_ILLEGAL" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 10044: ILLEGAL - Illegal Operation</name>
	$ -->		<section toc="exclude" anchor="OP_ILLEGAL_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<name>ARGUMENTS</name>
	<!-- Copyright (C) The Internet Society (2006) -->		<sourcecode type="xdr"><![CDATA[
	<section anchor="OP_ILLEGAL" title="Operation 10044: ILLEGAL - Illegal Operation		void;]]></sourcecode>
	" >		</section>
			<section toc="exclude" anchor="OP_ILLEGAL_RESULTS" numbered="true">
	<section toc="exclude" anchor="OP_ILLEGAL_ARGUMENTS" title="ARGUMENTS">		<name>RESULTS</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	void;
	</artwork>
	</figure>
	</section>
	<section toc="exclude" anchor="OP_ILLEGAL_RESULTS" title="RESULTS">
	<figure>
	<artwork>
	struct ILLEGAL4res {		struct ILLEGAL4res {
	nfsstat4 status;		nfsstat4 status;
	};		};]]></sourcecode>
			</section>
	</artwork>		<section toc="exclude" anchor="OP_ILLEGAL_DESCRIPTION" numbered="true">
	</figure>		<name>DESCRIPTION</name>
	</section>		<t>
	<section toc="exclude" anchor="OP_ILLEGAL_DESCRIPTION" title="DESCRIPTION">
	<t>
	This operation is a placeholder for encoding a result to handle the		This operation is a placeholder for encoding a result to handle the
	case of the client sending an operation code within COMPOUND that is		case of the client sending an operation code within COMPOUND that is
	not supported. See the COMPOUND procedure description for more		not supported. See the COMPOUND procedure description for more
	details.		details.
	</t>		</t>
	<t>		<t>
	The status field of ILLEGAL4res MUST be set to NFS4ERR_OP_ILLEGAL.		The status field of ILLEGAL4res <bcp14>MUST</bcp14> be set to NFS4ERR_OP_I
	</t>		LLEGAL.
	</section>		</t>
	<section toc="exclude" anchor="OP_ILLEGAL_IMPLEMENTATION" title="IMPLEMENTATIO		</section>
	N">		<section toc="exclude" anchor="OP_ILLEGAL_IMPLEMENTATION" numbered="true
	<t>		">
			<name>IMPLEMENTATION</name>
			<t>
	A client will probably not send an operation with code OP_ILLEGAL but		A client will probably not send an operation with code OP_ILLEGAL but
	if it does, the response will be ILLEGAL4res just as it would be with		if it does, the response will be ILLEGAL4res just as it would be with
	any other invalid operation code. Note that if the server gets an		any other invalid operation code. Note that if the server gets an
	illegal operation code that is not OP_ILLEGAL, and if the server		illegal operation code that is not OP_ILLEGAL, and if the server
	checks for legal operation codes during the XDR decode phase, then the		checks for legal operation codes during the XDR decode phase, then the
	ILLEGAL4res would not be returned.		ILLEGAL4res would not be returned.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->
	<!-- Copyright (C) The IETF Trust (2007) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="nfsv41callbackprocedures" numbered="true" toc="default">
	$ -->		<name>NFSv4.1 Callback Procedures</name>
	<!-- Copyright (C) The IETF Trust (2007) -->		<t>
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="nfsv41callbackprocedures" title="NFSv4.1 Callback Procedures">
	<t>
	The procedures used for callbacks are defined in the following		The procedures used for callbacks are defined in the following
	sections. In the interest of clarity, the terms "client" and "server"		sections. In the interest of clarity, the terms "client" and "server"
	refer to NFS clients and servers, despite the fact that for an		refer to NFS clients and servers, despite the fact that for an
	individual callback RPC, the sense of these terms would be precisely		individual callback RPC, the sense of these terms would be precisely
	the opposite.		the opposite.
	</t>		</t>
	<t>		<t>
	Both procedures, CB_NULL and CB_COMPOUND, MUST be implemented.		Both procedures, CB_NULL and CB_COMPOUND, <bcp14>MUST</bcp14> be implemented.
	</t>		</t>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="PROC_CB_NULL" numbered="true" toc="default">
	$ -->		<name>Procedure 0: CB_NULL - No Operation</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="PROC_CB_NULL_ARGUMENTS" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENTS</name>
	<section anchor="PROC_CB_NULL" title="Procedure 0: CB_NULL - No Operation" >		<sourcecode type="xdr"><![CDATA[
			void;]]></sourcecode>
	<section toc="exclude" anchor="PROC_CB_NULL_ARGUMENTS" title="ARGUMENTS">		</section>
	<figure>		<section toc="exclude" anchor="PROC_CB_NULL_RESULTS" numbered="true">
	<artwork>		<name>RESULTS</name>
	void;		<sourcecode type="xdr"><![CDATA[
	</artwork>		void;]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="PROC_CB_NULL_DESCRIPTION" numbered="true"
			>
	<section toc="exclude" anchor="PROC_CB_NULL_RESULTS" title="RESULTS">		<name>DESCRIPTION</name>
	<figure>		<t>
	<artwork>
	void;
	</artwork>
	</figure>
	</section>
	<section toc="exclude" anchor="PROC_CB_NULL_DESCRIPTION" title="DESCRIPTION">
	<t>
	CB_NULL is the standard ONC RPC NULL procedure, with the standard void arg ument and void response. Even though		CB_NULL is the standard ONC RPC NULL procedure, with the standard void arg ument and void response. Even though
	there is no direct functionality associated with this procedure, the		there is no direct functionality associated with this procedure, the
	server will use CB_NULL to confirm the existence of a path for RPCs		server will use CB_NULL to confirm the existence of a path for RPCs
	from the server to client.		from the server to client.
	</t>		</t>
			</section>
	</section>		<section toc="exclude" anchor="PROC_CB_NULL_ERRORS" numbered="true">
			<name>ERRORS</name>
	<section toc="exclude" anchor="PROC_CB_NULL_ERRORS" title="ERRORS">		<t>
	<t>
	None.		None.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="PROC_CB_COMPOUND" numbered="true" toc="default">
	$ -->		<name>Procedure 1: CB_COMPOUND - Compound Operations</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="PROC_CB_COMPOUND_ARGUMENTS" numbered="tru
	<!-- Copyright (C) The Internet Society (2006) -->		e">
	<section anchor="PROC_CB_COMPOUND" title="Procedure 1: CB_COMPOUND - Compound Op		<name>ARGUMENTS</name>
	erations" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="PROC_CB_COMPOUND_ARGUMENTS" title="ARGUMENTS">
	<figure>
	<artwork>
	enum nfs_cb_opnum4 {		enum nfs_cb_opnum4 {
	OP_CB_GETATTR = 3,		OP_CB_GETATTR = 3,
	OP_CB_RECALL = 4,		OP_CB_RECALL = 4,
	/* Callback operations new to NFSv4.1 */		/* Callback operations new to NFSv4.1 */
	OP_CB_LAYOUTRECALL = 5,		OP_CB_LAYOUTRECALL = 5,
	OP_CB_NOTIFY = 6,		OP_CB_NOTIFY = 6,
	OP_CB_PUSH_DELEG = 7,		OP_CB_PUSH_DELEG = 7,
	OP_CB_RECALL_ANY = 8,		OP_CB_RECALL_ANY = 8,
	OP_CB_RECALLABLE_OBJ_AVAIL = 9,		OP_CB_RECALLABLE_OBJ_AVAIL = 9,
	OP_CB_RECALL_SLOT = 10,		OP_CB_RECALL_SLOT = 10,
	OP_CB_SEQUENCE = 11,		OP_CB_SEQUENCE = 11,
	OP_CB_WANTS_CANCELLED = 12,		OP_CB_WANTS_CANCELLED = 12,
	OP_CB_NOTIFY_LOCK = 13,		OP_CB_NOTIFY_LOCK = 13,
	OP_CB_NOTIFY_DEVICEID = 14,		OP_CB_NOTIFY_DEVICEID = 14,
	OP_CB_ILLEGAL = 10044		OP_CB_ILLEGAL = 10044
	};		};
	</artwork>
	</figure>
	<figure>
	<artwork>
	union nfs_cb_argop4 switch (unsigned argop) {		union nfs_cb_argop4 switch (unsigned argop) {
	case OP_CB_GETATTR:		case OP_CB_GETATTR:
	CB_GETATTR4args opcbgetattr;		CB_GETATTR4args opcbgetattr;
	case OP_CB_RECALL:		case OP_CB_RECALL:
	CB_RECALL4args opcbrecall;		CB_RECALL4args opcbrecall;
	case OP_CB_LAYOUTRECALL:		case OP_CB_LAYOUTRECALL:
	CB_LAYOUTRECALL4args opcblayoutrecall;		CB_LAYOUTRECALL4args opcblayoutrecall;
	case OP_CB_NOTIFY:		case OP_CB_NOTIFY:
	CB_NOTIFY4args opcbnotify;		CB_NOTIFY4args opcbnotify;
	case OP_CB_PUSH_DELEG:		case OP_CB_PUSH_DELEG:
	skipping to change at line 40299 ¶		skipping to change at line 40177 ¶
	case OP_CB_SEQUENCE:		case OP_CB_SEQUENCE:
	CB_SEQUENCE4args opcbsequence;		CB_SEQUENCE4args opcbsequence;
	case OP_CB_WANTS_CANCELLED:		case OP_CB_WANTS_CANCELLED:
	CB_WANTS_CANCELLED4args opcbwants_cancelled;		CB_WANTS_CANCELLED4args opcbwants_cancelled;
	case OP_CB_NOTIFY_LOCK:		case OP_CB_NOTIFY_LOCK:
	CB_NOTIFY_LOCK4args opcbnotify_lock;		CB_NOTIFY_LOCK4args opcbnotify_lock;
	case OP_CB_NOTIFY_DEVICEID:		case OP_CB_NOTIFY_DEVICEID:
	CB_NOTIFY_DEVICEID4args opcbnotify_deviceid;		CB_NOTIFY_DEVICEID4args opcbnotify_deviceid;
	case OP_CB_ILLEGAL: void;		case OP_CB_ILLEGAL: void;
	};		};
	</artwork>
	</figure>
	<figure>
	<artwork>
	struct CB_COMPOUND4args {		struct CB_COMPOUND4args {
	utf8str_cs tag;		utf8str_cs tag;
	uint32_t minorversion;		uint32_t minorversion;
	uint32_t callback_ident;		uint32_t callback_ident;
	nfs_cb_argop4 argarray&lt;>;		nfs_cb_argop4 argarray<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
			<section toc="exclude" anchor="PROC_CB_COMPOUND_RESULTS" numbered="true"
	</section>		>
			<name>RESULTS</name>
	<section toc="exclude" anchor="PROC_CB_COMPOUND_RESULTS" title="RESULTS">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	union nfs_cb_resop4 switch (unsigned resop) {		union nfs_cb_resop4 switch (unsigned resop) {
	case OP_CB_GETATTR: CB_GETATTR4res opcbgetattr;		case OP_CB_GETATTR: CB_GETATTR4res opcbgetattr;
	case OP_CB_RECALL: CB_RECALL4res opcbrecall;		case OP_CB_RECALL: CB_RECALL4res opcbrecall;
	/* new NFSv4.1 operations */		/* new NFSv4.1 operations */
	case OP_CB_LAYOUTRECALL:		case OP_CB_LAYOUTRECALL:
	CB_LAYOUTRECALL4res		CB_LAYOUTRECALL4res
	opcblayoutrecall;		opcblayoutrecall;
	case OP_CB_NOTIFY: CB_NOTIFY4res opcbnotify;		case OP_CB_NOTIFY: CB_NOTIFY4res opcbnotify;
	skipping to change at line 40359 ¶		skipping to change at line 40231 ¶
	CB_NOTIFY_LOCK4res		CB_NOTIFY_LOCK4res
	opcbnotify_lock;		opcbnotify_lock;
	case OP_CB_NOTIFY_DEVICEID:		case OP_CB_NOTIFY_DEVICEID:
	CB_NOTIFY_DEVICEID4res		CB_NOTIFY_DEVICEID4res
	opcbnotify_deviceid;		opcbnotify_deviceid;
	/* Not new operation */		/* Not new operation */
	case OP_CB_ILLEGAL: CB_ILLEGAL4res opcbillegal;		case OP_CB_ILLEGAL: CB_ILLEGAL4res opcbillegal;
	};		};
	</artwork>
	</figure>
	<figure>
	<artwork>
	struct CB_COMPOUND4res {		struct CB_COMPOUND4res {
	nfsstat4 status;		nfsstat4 status;
	utf8str_cs tag;		utf8str_cs tag;
	nfs_cb_resop4 resarray&lt;>;		nfs_cb_resop4 resarray<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_COMPOUND_DESCRIPTION" numbered="tru
			e">
	<section toc="exclude" anchor="OP_CB_COMPOUND_DESCRIPTION" title="DESCRIPTION"		<name>DESCRIPTION</name>
	>		<t>
	<t>
	The CB_COMPOUND procedure is used to combine one or more of the		The CB_COMPOUND procedure is used to combine one or more of the
	callback procedures into a single RPC request. The main callback RPC		callback procedures into a single RPC request. The main callback RPC
	program has two main procedures: CB_NULL and CB_COMPOUND. All other		program has two main procedures: CB_NULL and CB_COMPOUND. All other
	operations use the CB_COMPOUND procedure as a wrapper.		operations use the CB_COMPOUND procedure as a wrapper.
	</t>		</t>
	<t>		<t>
	During the processing of the CB_COMPOUND procedure, the client may find		During the processing of the CB_COMPOUND procedure, the client may find
	that it does not have the available resources to execute any or all of		that it does not have the available resources to execute any or all of
	the operations within the CB_COMPOUND sequence.		the operations within the CB_COMPOUND sequence.
	Refer to <xref target="COMPOUND_Sizing_Issues" /> for details.		Refer to <xref target="COMPOUND_Sizing_Issues" format="default"/> for deta
	</t>		ils.
	<t>		</t>
	The minorversion field of the arguments MUST be the same as the		<t>
			The minorversion field of the arguments <bcp14>MUST</bcp14> be the same as
			the
	minorversion of the COMPOUND procedure used to create the client ID		minorversion of the COMPOUND procedure used to create the client ID
	and session. For NFSv4.1, minorversion MUST be set to 1.		and session. For NFSv4.1, minorversion <bcp14>MUST</bcp14> be set to 1.
	</t>		</t>
	<t>		<t>
	Contained within the CB_COMPOUND results is a "status" field. This		Contained within the CB_COMPOUND results is a "status" field. This
	status MUST be equal to the status of the last operation that was		status <bcp14>MUST</bcp14> be equal to the status of the last operation th at was
	executed within the CB_COMPOUND procedure. Therefore, if an operation		executed within the CB_COMPOUND procedure. Therefore, if an operation
	incurred an error, then the "status" value will be the same error value		incurred an error, then the "status" value will be the same error value
	as is being returned for the operation that failed.		as is being returned for the operation that failed.
	</t>		</t>
	<t>		<t>
	The "tag" field is handled the same way as that of the COMPOUND		The "tag" field is handled the same way as that of the COMPOUND
	procedure (see <xref target="OP_COMPOUND_DESCRIPTION" />).		procedure (see <xref target="OP_COMPOUND_DESCRIPTION" format="default"/>).
	</t>		</t>
	<t>		<t>
	Illegal operation codes are handled in the same way as they are		Illegal operation codes are handled in the same way as they are
	handled for the COMPOUND procedure.		handled for the COMPOUND procedure.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="PROC_CB_COMPOUND_IMPLEMENTATION" title="IMPLEME		<section toc="exclude" anchor="PROC_CB_COMPOUND_IMPLEMENTATION" numbered
	NTATION">		="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	The CB_COMPOUND procedure is used to combine individual operations		The CB_COMPOUND procedure is used to combine individual operations
	into a single RPC request. The client interprets each of the		into a single RPC request. The client interprets each of the
	operations in turn. If an operation is executed by the client and		operations in turn. If an operation is executed by the client and
	the status of that operation is NFS4_OK, then the next operation in		the status of that operation is NFS4_OK, then the next operation in
	the CB_COMPOUND procedure is executed. The client continues this		the CB_COMPOUND procedure is executed. The client continues this
	process until there are no more operations to be executed or one of		process until there are no more operations to be executed or one of
	the operations has a status value other than NFS4_OK.		the operations has a status value other than NFS4_OK.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_CB_COMPOUND_ERRORS" title="ERRORS">		<section toc="exclude" anchor="OP_CB_COMPOUND_ERRORS" numbered="true">
	<t>		<name>ERRORS</name>
			<t>
	CB_COMPOUND will of course return every error that each operation on		CB_COMPOUND will of course return every error that each operation on
	the backchannel can return (see <xref target="cb_op_error_returns"/>).		the backchannel can return (see <xref target="cb_op_error_returns" format=" default"/>).
	However, if CB_COMPOUND returns zero operations, obviously the error		However, if CB_COMPOUND returns zero operations, obviously the error
	returned by COMPOUND has nothing to do with an error returned by		returned by COMPOUND has nothing to do with an error returned by
	an operation. The list of errors CB_COMPOUND will return if it processes		an operation. The list of errors CB_COMPOUND will return if it processes
	zero operations includes:		zero operations includes:
	</t>		</t>
	<texttable anchor="CB_compounderrs">		<table anchor="CB_compounderrs" align="center">
	<preamble>CB_COMPOUND error returns</preamble>		<name>CB_COMPOUND Error Returns</name>
	<ttcol align='left'>Error</ttcol>		<thead>
	<ttcol align='left'>Notes</ttcol>		<tr>
			<th align="left">Error</th>
	<c>NFS4ERR_BADCHAR</c> <c>The tag argument has a character the replier		<th align="left">Notes</th>
	does not support. </c>		</tr>
			</thead>
	<c>NFS4ERR_BADXDR</c> <c> </c>		<tbody>
			<tr>
	<c>NFS4ERR_DELAY</c> <c> </c>		<td align="left">NFS4ERR_BADCHAR</td>
			<td align="left">The tag argument has a character the replier
	<c>NFS4ERR_INVAL</c> <c>The tag argument is not in UTF-8 encoding.</c>		does not support. </td>
			</tr>
	<c>NFS4ERR_MINOR_VERS_MISMATCH</c> <c> </c>		<tr>
			<td align="left">NFS4ERR_BADXDR</td>
	<c>NFS4ERR_SERVERFAULT</c> <c> </c>		<td align="left"> </td>
			</tr>
	<c>NFS4ERR_TOO_MANY_OPS</c> <c> </c>		<tr>
			<td align="left">NFS4ERR_DELAY</td>
	<c>NFS4ERR_REP_TOO_BIG</c> <c> </c>		<td align="left"> </td>
			</tr>
	<c>NFS4ERR_REP_TOO_BIG_TO_CACHE</c> <c> </c>		<tr>
			<td align="left">NFS4ERR_INVAL</td>
	<c>NFS4ERR_REQ_TOO_BIG</c> <c> </c>		<td align="left">The tag argument is not in UTF-8 encoding.</td>
			</tr>
	</texttable>		<tr>
			<td align="left">NFS4ERR_MINOR_VERS_MISMATCH</td>
	</section>		<td align="left"> </td>
	</section>		</tr>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<tr>
	$ -->		<td align="left">NFS4ERR_SERVERFAULT</td>
	<!-- Copyright (C) The IETF Trust (2007) -->		<td align="left"> </td>
	<!-- Copyright (C) The Internet Society (2006) -->		</tr>
			<tr>
			<td align="left">NFS4ERR_TOO_MANY_OPS</td>
			<td align="left"> </td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_REP_TOO_BIG</td>
			<td align="left"> </td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_REP_TOO_BIG_TO_CACHE</td>
			<td align="left"> </td>
			</tr>
			<tr>
			<td align="left">NFS4ERR_REQ_TOO_BIG</td>
			<td align="left"> </td>
			</tr>
			</tbody>
			</table>
			</section>
			</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="nfsv41cboperations" numbered="true" toc="default">
	$ -->		<name>NFSv4.1 Callback Operations</name>
	<!-- Copyright (C) The IETF Trust (2007) -->		<section anchor="OP_CB_GETATTR" numbered="true" toc="default">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>Operation 3: CB_GETATTR - Get Attributes</name>
	<section anchor="nfsv41cboperations" title="NFSv4.1 Callback Operations">		<section toc="exclude" anchor="OP_CB_GETATTR_ARGUMENT" numbered="true">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>ARGUMENT</name>
	$ -->		<sourcecode type="xdr"><![CDATA[
	<!-- Copyright (C) The IETF Trust (2007) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="OP_CB_GETATTR" title="Operation 3: CB_GETATTR - Get Attributes"
	>
	<section toc="exclude" anchor="OP_CB_GETATTR_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct CB_GETATTR4args {		struct CB_GETATTR4args {
	nfs_fh4 fh;		nfs_fh4 fh;
	bitmap4 attr_request;		bitmap4 attr_request;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_GETATTR_RESULT" numbered="true">
	<section toc="exclude" anchor="OP_CB_GETATTR_RESULT" title="RESULT">		<name>RESULT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct CB_GETATTR4resok {		struct CB_GETATTR4resok {
	fattr4 obj_attributes;		fattr4 obj_attributes;
	};		};
	union CB_GETATTR4res switch (nfsstat4 status) {		union CB_GETATTR4res switch (nfsstat4 status) {
	case NFS4_OK:		case NFS4_OK:
	CB_GETATTR4resok resok4;		CB_GETATTR4resok resok4;
	default:		default:
	void;		void;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_GETATTR_DESCRIPTION" numbered="true
	<section toc="exclude" anchor="OP_CB_GETATTR_DESCRIPTION" title="DESCRIPTION">		">
	<t>		<name>DESCRIPTION</name>
			<t>
	The CB_GETATTR operation is used by the server to obtain the		The CB_GETATTR operation is used by the server to obtain the
	current modified state of a file that has been OPEN_DELEGATE_WRITE delegate d.		current modified state of a file that has been OPEN_DELEGATE_WRITE delegate d.
	The size and change attributes are the only ones guaranteed to be		The size and change attributes are the only ones guaranteed to be
	serviced by the client. See <xref		serviced by the client. See <xref target="handling_cb_getattr" format="def
	target="handling_cb_getattr"/> for a full description		ault"/> for a full description
	of how the client and server are to interact with		of how the client and server are to interact with
	the use of CB_GETATTR.		the use of CB_GETATTR.
	</t>		</t>
	<t>		<t>
	If the filehandle specified is not one for which the client holds an		If the filehandle specified is not one for which the client holds an
	OPEN_DELEGATE_WRITE delegation, an NFS4ERR_BADHANDLE error is returned.		OPEN_DELEGATE_WRITE delegation, an NFS4ERR_BADHANDLE error is returned.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_CB_GETATTR_IMPLEMENTATION" title="IMPLEMENTA		<section toc="exclude" anchor="OP_CB_GETATTR_IMPLEMENTATION" numbered="t
	TION">		rue">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	The client returns attrmask bits and the associated attribute		The client returns attrmask bits and the associated attribute
	values only for the change attribute, and attributes that it may		values only for the change attribute, and attributes that it may
	change (time_modify, and size).		change (time_modify, and size).
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_CB_RECALL" numbered="true" toc="default">
	$ -->		<name>Operation 4: CB_RECALL - Recall a Delegation</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_CB_RECALL_ARGUMENT" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_CB_RECALL" title="Operation 4: CB_RECALL - Recall a Delegati		<sourcecode type="xdr"><![CDATA[
	on" >
	<section toc="exclude" anchor="OP_CB_RECALL_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct CB_RECALL4args {		struct CB_RECALL4args {
	stateid4 stateid;		stateid4 stateid;
	bool truncate;		bool truncate;
	nfs_fh4 fh;		nfs_fh4 fh;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_RECALL_RESULT" numbered="true">
	<section toc="exclude" anchor="OP_CB_RECALL_RESULT" title="RESULT">		<name>RESULT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct CB_RECALL4res {		struct CB_RECALL4res {
	nfsstat4 status;		nfsstat4 status;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_RECALL_DESCRIPTION" numbered="true"
	<section toc="exclude" anchor="OP_CB_RECALL_DESCRIPTION" title="DESCRIPTION">		>
	<t>		<name>DESCRIPTION</name>
			<t>
	The CB_RECALL operation is used to begin the process of recalling		The CB_RECALL operation is used to begin the process of recalling
	a delegation and returning it to the server.		a delegation and returning it to the server.
	</t>		</t>
	<t>		<t>
	The truncate flag is used to optimize recall for a file object that		The truncate flag is used to optimize recall for a file object that
	is a regular file and is		is a regular file and is
	about to be truncated to zero. When it is TRUE, the client is freed		about to be truncated to zero. When it is TRUE, the client is freed
	of the obligation to propagate modified data for the file to the		of the obligation to propagate modified data for the file to the
	server, since this data is irrelevant.		server, since this data is irrelevant.
	</t>		</t>
	<t>		<t>
	If the handle specified is not one for which the client holds a		If the handle specified is not one for which the client holds a
	delegation, an NFS4ERR_BADHANDLE error is returned.		delegation, an NFS4ERR_BADHANDLE error is returned.
	</t>		</t>
	<t>		<t>
	If the stateid specified is not one corresponding to an OPEN		If the stateid specified is not one corresponding to an OPEN
	delegation for the file specified by the filehandle, an		delegation for the file specified by the filehandle, an
	NFS4ERR_BAD_STATEID is returned.		NFS4ERR_BAD_STATEID is returned.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_CB_RECALL_IMPLEMENTATION" title="IMPLEMENTAT		<section toc="exclude" anchor="OP_CB_RECALL_IMPLEMENTATION" numbered="tr
	ION">		ue">
	<t>		<name>IMPLEMENTATION</name>
	The client SHOULD reply to the callback immediately.		<t>
			The client <bcp14>SHOULD</bcp14> reply to the callback immediately.
	Replying does not complete the recall except when		Replying does not complete the recall except when
	the value of the reply's status field is neither		the value of the reply's status field is neither
	NFS4ERR_DELAY nor NFS4_OK. The recall is not complete		NFS4ERR_DELAY nor NFS4_OK. The recall is not complete
	until the delegation is returned using a DELEGRETURN		until the delegation is returned using a DELEGRETURN
	operation.		operation.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_CB_LAYOUTRECALL" numbered="true" toc="default">
	$ -->		<name>Operation 5: CB_LAYOUTRECALL - Recall Layout from Client</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_CB_LAYOUTRECALL_ARGUMENT" numbered="tr
	<!-- Copyright (C) The Internet Society (2006) -->		ue">
	<section anchor="OP_CB_LAYOUTRECALL"		<name>ARGUMENT</name>
	title="Operation 5: CB_LAYOUTRECALL - Recall Layout from Client" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_CB_LAYOUTRECALL_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	/*		/*
	* NFSv4.1 callback arguments and results		* NFSv4.1 callback arguments and results
	*/		*/
	enum layoutrecall_type4 {		enum layoutrecall_type4 {
	LAYOUTRECALL4_FILE = LAYOUT4_RET_REC_FILE,		LAYOUTRECALL4_FILE = LAYOUT4_RET_REC_FILE,
	LAYOUTRECALL4_FSID = LAYOUT4_RET_REC_FSID,		LAYOUTRECALL4_FSID = LAYOUT4_RET_REC_FSID,
	LAYOUTRECALL4_ALL = LAYOUT4_RET_REC_ALL		LAYOUTRECALL4_ALL = LAYOUT4_RET_REC_ALL
	};		};
	skipping to change at line 40623 ¶		skipping to change at line 40501 ¶
	case LAYOUTRECALL4_ALL:		case LAYOUTRECALL4_ALL:
	void;		void;
	};		};
	struct CB_LAYOUTRECALL4args {		struct CB_LAYOUTRECALL4args {
	layouttype4 clora_type;		layouttype4 clora_type;
	layoutiomode4 clora_iomode;		layoutiomode4 clora_iomode;
	bool clora_changed;		bool clora_changed;
	layoutrecall4 clora_recall;		layoutrecall4 clora_recall;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_LAYOUTRECALL_RESULT" numbered="true
	<section toc="exclude" anchor="OP_CB_LAYOUTRECALL_RESULT" title="RESULT">		">
	<figure>		<name>RESULT</name>
	<artwork>		<sourcecode type="xdr"><![CDATA[
	struct CB_LAYOUTRECALL4res {		struct CB_LAYOUTRECALL4res {
	nfsstat4 clorr_status;		nfsstat4 clorr_status;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_LAYOUTRECALL_DESCRIPTION" numbered=
	<section toc="exclude" anchor="OP_CB_LAYOUTRECALL_DESCRIPTION" title="DESCRIPT		"true">
	ION">		<name>DESCRIPTION</name>
	<t>		<t>
	The CB_LAYOUTRECALL operation is used by the server to recall		The CB_LAYOUTRECALL operation is used by the server to recall
	layouts from the client; as a result, the client will begin the		layouts from the client; as a result, the client will begin the
	process of returning layouts via LAYOUTRETURN. The		process of returning layouts via LAYOUTRETURN. The
	CB_LAYOUTRECALL operation specifies one of three forms of recall		CB_LAYOUTRECALL operation specifies one of three forms of recall
	processing with the value of layoutrecall_type4. The recall is		processing with the value of layoutrecall_type4. The recall is
	for one of the following: a specific layout of a specific file		for one of the following: a specific layout of a specific file
	(LAYOUTRECALL4_FILE), an entire file system ID		(LAYOUTRECALL4_FILE), an entire file system ID
	(LAYOUTRECALL4_FSID), or all file systems (LAYOUTRECALL4_ALL).		(LAYOUTRECALL4_FSID), or all file systems (LAYOUTRECALL4_ALL).
	</t>		</t>
	<t>		<t>
	The behavior of the operation varies based on the value of the		The behavior of the operation varies based on the value of the
	layoutrecall_type4. The value and behaviors are:		layoutrecall_type4. The value and behaviors are:
	<list style="hanging">		</t>
	<t hangText="LAYOUTRECALL4_FILE"></t>		<dl newline="true" spacing="normal">
	<t>		<dt>LAYOUTRECALL4_FILE</dt>
			<dd><t>
	For a layout to match the recall request, the values of the following fi elds		For a layout to match the recall request, the values of the following fi elds
	must match those of the layout: clora_type, clora_iomode,		must match those of the layout: clora_type, clora_iomode,
	lor_fh, and the byte-range specified by lor_offset and		lor_fh, and the byte-range specified by lor_offset and
	lor_length. The clora_iomode field may have a special value		lor_length. The clora_iomode field may have a special value
	of LAYOUTIOMODE4_ANY. The special value LAYOUTIOMODE4_ANY will match an y		of LAYOUTIOMODE4_ANY. The special value LAYOUTIOMODE4_ANY will match an y
	iomode originally returned in a layout; therefore, it acts as a		iomode originally returned in a layout; therefore, it acts as a
	wild card. The other special value used is for		wild card. The other special value used is for
	lor_length. If lor_length has a value of NFS4_UINT64_MAX, the		lor_length. If lor_length has a value of NFS4_UINT64_MAX, the
	lor_length field means the maximum possible file size. If a		lor_length field means the maximum possible file size. If a
	matching layout is found, it MUST be returned using the		matching layout is found, it <bcp14>MUST</bcp14> be returned using the
	LAYOUTRETURN operation (see <xref target="OP_LAYOUTRETURN" />).		LAYOUTRETURN operation (see <xref target="OP_LAYOUTRETURN" format="defau
			lt"/>).
	An example of the field's special value use is if clora_iomode		An example of the field's special value use is if clora_iomode
	is LAYOUTIOMODE4_ANY, lor_offset is zero, and lor_length is		is LAYOUTIOMODE4_ANY, lor_offset is zero, and lor_length is
	NFS4_UINT64_MAX, then the entire layout is to be returned.		NFS4_UINT64_MAX, then the entire layout is to be returned.</t>
	</t>		<t>
	<t>
	The NFS4ERR_NOMATCHING_LAYOUT error is only returned when the		The NFS4ERR_NOMATCHING_LAYOUT error is only returned when the
	client does not hold layouts for the file or if the client		client does not hold layouts for the file or if the client
	does not have any overlapping layouts for the specification in		does not have any overlapping layouts for the specification in
	the layout recall.		the layout recall.</t>
	</t>		</dd>
	<t hangText="LAYOUTRECALL4_FSID and LAYOUTRECALL4_ALL"></t>		<dt>LAYOUTRECALL4_FSID and LAYOUTRECALL4_ALL</dt>
	<t>		<dd><t>
	If LAYOUTRECALL4_FSID is specified, the fsid specifies the		If LAYOUTRECALL4_FSID is specified, the fsid specifies the
	file system for which any outstanding layouts MUST be		file system for which any outstanding layouts <bcp14>MUST</bcp14> be
	returned. If LAYOUTRECALL4_ALL is specified, all outstanding		returned. If LAYOUTRECALL4_ALL is specified, all outstanding
	layouts MUST be returned. In addition, LAYOUTRECALL4_FSID and		layouts <bcp14>MUST</bcp14> be returned. In addition, LAYOUTRECALL4_FSI D and
	LAYOUTRECALL4_ALL specify that all the storage device ID to		LAYOUTRECALL4_ALL specify that all the storage device ID to
	storage device address mappings in the affected file system(s)		storage device address mappings in the affected file system(s)
	are also recalled. The respective LAYOUTRETURN with either		are also recalled. The respective LAYOUTRETURN with either
	LAYOUTRETURN4_FSID or LAYOUTRETURN4_ALL acknowledges to the		LAYOUTRETURN4_FSID or LAYOUTRETURN4_ALL acknowledges to the
	server that the client invalidated the said device mappings.		server that the client invalidated the said device mappings.
	See <xref target="bulk_layouts" /> for considerations with		See <xref target="bulk_layouts" format="default"/> for considerations wi th
	"bulk" recall of layouts.		"bulk" recall of layouts.
	</t>		</t>
	<t>		<t>
	The NFS4ERR_NOMATCHING_LAYOUT error is only returned when the		The NFS4ERR_NOMATCHING_LAYOUT error is only returned when the
	client does not hold layouts and does not have valid deviceid		client does not hold layouts and does not have valid deviceid
	mappings.		mappings.</t>
	</t>		</dd>
	</list>		</dl>
	</t>		<t>
	<t>
	In processing the layout recall request, the client also varies		In processing the layout recall request, the client also varies
	its behavior based on the value of the clora_changed field. This		its behavior based on the value of the clora_changed field. This
	field is used by the server to provide additional context for		field is used by the server to provide additional context for
	the reason why the layout is being recalled. A FALSE value for		the reason why the layout is being recalled. A FALSE value for
	clora_changed indicates that no change in the layout is expected		clora_changed indicates that no change in the layout is expected
	and the client may write modified data to the storage devices		and the client may write modified data to the storage devices
	involved; this must be done prior to returning the layout via		involved; this must be done prior to returning the layout via
	LAYOUTRETURN. A TRUE value for clora_changed indicates that the		LAYOUTRETURN. A TRUE value for clora_changed indicates that the
	server is changing the layout. Examples of layout changes and		server is changing the layout. Examples of layout changes and
	reasons for a TRUE indication are the following: the metadata server is re striping		reasons for a TRUE indication are the following: the metadata server is re striping
	the file or a permanent error has occurred on a storage device		the file or a permanent error has occurred on a storage device
	and the metadata server would like to provide a new layout for		and the metadata server would like to provide a new layout for
	the file. Therefore, a clora_changed value of TRUE indicates		the file. Therefore, a clora_changed value of TRUE indicates
	some level of change for the layout and the client SHOULD NOT		some level of change for the layout and the client <bcp14>SHOULD NOT</bcp1 4>
	write and commit modified data to the storage devices. In this		write and commit modified data to the storage devices. In this
	case, the client writes and commits data through the metadata		case, the client writes and commits data through the metadata
	server.		server.
	</t>		</t>
	<t>		<t>
	See <xref target="layout_stateid"/> for a description of how the		See <xref target="layout_stateid" format="default"/> for a description of
			how the
	lor_stateid field in the arguments is to be constructed. Note		lor_stateid field in the arguments is to be constructed. Note
	that the "seqid" field of lor_stateid MUST NOT be zero. See Sections		that the "seqid" field of lor_stateid <bcp14>MUST NOT</bcp14> be zero. Se
	<xref target="stateid" format="counter" />, <xref		e Sections
	target="layout_stateid" format="counter" />, and		<xref target="stateid" format="counter"/>, <xref target="layout_stateid" f
	<xref target="pnfs_operation_sequencing" format="counter" /> for a further		ormat="counter"/>, and
			<xref target="pnfs_operation_sequencing" format="counter"/> for a further
	discussion and requirements.		discussion and requirements.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_CB_LAYOUTRECALL_IMPLEMENTATION" title="IMPLE		<section toc="exclude" anchor="OP_CB_LAYOUTRECALL_IMPLEMENTATION" number
	MENTATION">		ed="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	The client's processing for CB_LAYOUTRECALL is similar to		The client's processing for CB_LAYOUTRECALL is similar to
	CB_RECALL (recall of file delegations) in that		CB_RECALL (recall of file delegations) in that
	the client responds to		the client responds to
	the request before actually returning layouts via the		the request before actually returning layouts via the
	LAYOUTRETURN operation. While the client responds to the		LAYOUTRETURN operation. While the client responds to the
	CB_LAYOUTRECALL immediately, the operation is not considered		CB_LAYOUTRECALL immediately, the operation is not considered
	complete (i.e., considered pending) until all affected layouts are returne d to the server		complete (i.e., considered pending) until all affected layouts are returne d to the server
	via the LAYOUTRETURN operation.		via the LAYOUTRETURN operation.
	</t>		</t>
	<t>		<t>
	Before returning the layout to the server via LAYOUTRETURN, the		Before returning the layout to the server via LAYOUTRETURN, the
	client should wait for the response from in-process or in-flight		client should wait for the response from in-process or in-flight
	READ, WRITE, or COMMIT operations that use the recalled layout.		READ, WRITE, or COMMIT operations that use the recalled layout.
	</t>		</t>
	<t>		<t>
	If the client is holding modified data that is affected by a		If the client is holding modified data that is affected by a
	recalled layout, the client has various options for writing the		recalled layout, the client has various options for writing the
	data to the server. As always, the client may write the data		data to the server. As always, the client may write the data
	through the metadata server. In fact, the client may not have a		through the metadata server. In fact, the client may not have a
	choice other than writing to the metadata server when the		choice other than writing to the metadata server when the
	clora_changed argument is TRUE and a new layout is unavailable		clora_changed argument is TRUE and a new layout is unavailable
	from the server. However, the client may be able to write the		from the server. However, the client may be able to write the
	modified data to the storage device if the clora_changed		modified data to the storage device if the clora_changed
	argument is FALSE; this needs to be done before returning the		argument is FALSE; this needs to be done before returning the
	layout via LAYOUTRETURN. If the client were to obtain a new		layout via LAYOUTRETURN. If the client were to obtain a new
	layout covering the modified data's byte-range, then writing to the		layout covering the modified data's byte-range, then writing to the
	storage devices is an available alternative. Note that before		storage devices is an available alternative. Note that before
	obtaining a new layout, the client must first return the		obtaining a new layout, the client must first return the
	original layout.		original layout.
	</t>		</t>
	<t>		<t>
	In the case of modified data being written while the layout is		In the case of modified data being written while the layout is
	held, the client must use LAYOUTCOMMIT operations at the		held, the client must use LAYOUTCOMMIT operations at the
	appropriate time; as required LAYOUTCOMMIT must be done before		appropriate time; as required LAYOUTCOMMIT must be done before
	the LAYOUTRETURN. If a large amount of modified data is		the LAYOUTRETURN. If a large amount of modified data is
	outstanding, the client may send LAYOUTRETURNs for portions of		outstanding, the client may send LAYOUTRETURNs for portions of
	the recalled layout; this allows the server to monitor the		the recalled layout; this allows the server to monitor the
	client's progress and adherence to the original recall request.		client's progress and adherence to the original recall request.
	However, the last LAYOUTRETURN in a sequence of returns MUST		However, the last LAYOUTRETURN in a sequence of returns <bcp14>MUST</bcp14
	specify the full range being recalled (see <xref		>
	target="recall_robustness" /> for details).		specify the full range being recalled (see <xref target="recall_robustness
	</t>		" format="default"/> for details).
	<t>		</t>
			<t>
	If a server needs to delete a device ID and there are layouts		If a server needs to delete a device ID and there are layouts
	referring to the device ID, CB_LAYOUTRECALL MUST be invoked to		referring to the device ID, CB_LAYOUTRECALL <bcp14>MUST</bcp14> be invoked to
	cause the client to return all layouts referring to the device ID		cause the client to return all layouts referring to the device ID
	before the server can delete the device ID. If the client		before the server can delete the device ID. If the client
	does not return the affected layouts, the server MAY revoke		does not return the affected layouts, the server <bcp14>MAY</bcp14> revoke
	the layouts.		the layouts.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_CB_NOTIFY" numbered="true" toc="default">
	$ -->		<name>Operation 6: CB_NOTIFY - Notify Client of Directory Changes</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_CB_NOTIFY_ARGUMENT" numbered="true">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_CB_NOTIFY" title="Operation 6: CB_NOTIFY - Notify Client of		<sourcecode type="xdr"><![CDATA[
	Directory Changes" >
	<section toc="exclude" anchor="OP_CB_NOTIFY_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	/*		/*
	* Directory notification types.		* Directory notification types.
	*/		*/
	enum notify_type4 {		enum notify_type4 {
	NOTIFY4_CHANGE_CHILD_ATTRS = 0,		NOTIFY4_CHANGE_CHILD_ATTRS = 0,
	NOTIFY4_CHANGE_DIR_ATTRS = 1,		NOTIFY4_CHANGE_DIR_ATTRS = 1,
	NOTIFY4_REMOVE_ENTRY = 2,		NOTIFY4_REMOVE_ENTRY = 2,
	NOTIFY4_ADD_ENTRY = 3,		NOTIFY4_ADD_ENTRY = 3,
	NOTIFY4_RENAME_ENTRY = 4,		NOTIFY4_RENAME_ENTRY = 4,
	NOTIFY4_CHANGE_COOKIE_VERIFIER = 5		NOTIFY4_CHANGE_COOKIE_VERIFIER = 5
	skipping to change at line 40821 ¶		skipping to change at line 40693 ¶
	struct notify_remove4 {		struct notify_remove4 {
	notify_entry4 nrm_old_entry;		notify_entry4 nrm_old_entry;
	nfs_cookie4 nrm_old_entry_cookie;		nfs_cookie4 nrm_old_entry_cookie;
	};		};
	struct notify_add4 {		struct notify_add4 {
	/*		/*
	* Information on object		* Information on object
	* possibly renamed over.		* possibly renamed over.
	*/		*/
	notify_remove4 nad_old_entry&lt;1>;		notify_remove4 nad_old_entry<1>;
	notify_entry4 nad_new_entry;		notify_entry4 nad_new_entry;
	/* what READDIR would have returned for this entry */		/* what READDIR would have returned for this entry */
	nfs_cookie4 nad_new_entry_cookie&lt;1>;		nfs_cookie4 nad_new_entry_cookie<1>;
	prev_entry4 nad_prev_entry&lt;1>;		prev_entry4 nad_prev_entry<1>;
	bool nad_last_entry;		bool nad_last_entry;
	};		};
	struct notify_attr4 {		struct notify_attr4 {
	notify_entry4 na_changed_entry;		notify_entry4 na_changed_entry;
	};		};
	struct notify_rename4 {		struct notify_rename4 {
	notify_remove4 nrn_old_entry;		notify_remove4 nrn_old_entry;
	notify_add4 nrn_new_entry;		notify_add4 nrn_new_entry;
	};		};
	struct notify_verifier4 {		struct notify_verifier4 {
	verifier4 nv_old_cookieverf;		verifier4 nv_old_cookieverf;
	verifier4 nv_new_cookieverf;		verifier4 nv_new_cookieverf;
	};		};
	/*		/*
	* Objects of type notify_&lt;>4 and		* Objects of type notify_<>4 and
	* notify_device_&lt;>4 are encoded in this.		* notify_device_<>4 are encoded in this.
	*/		*/
	typedef opaque notifylist4&lt;>;		typedef opaque notifylist4<>;
	struct notify4 {		struct notify4 {
	/* composed from notify_type4 or notify_deviceid_type4 */		/* composed from notify_type4 or notify_deviceid_type4 */
	bitmap4 notify_mask;		bitmap4 notify_mask;
	notifylist4 notify_vals;		notifylist4 notify_vals;
	};		};
	struct CB_NOTIFY4args {		struct CB_NOTIFY4args {
	stateid4 cna_stateid;		stateid4 cna_stateid;
	nfs_fh4 cna_fh;		nfs_fh4 cna_fh;
	notify4 cna_changes&lt;>;		notify4 cna_changes<>;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_NOTIFY_RESULT" numbered="true">
	<section toc="exclude" anchor="OP_CB_NOTIFY_RESULT" title="RESULT">		<name>RESULT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct CB_NOTIFY4res {		struct CB_NOTIFY4res {
	nfsstat4 cnr_status;		nfsstat4 cnr_status;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_NOTIFY_DESCRIPTION" numbered="true"
	<section toc="exclude" anchor="OP_CB_NOTIFY_DESCRIPTION" title="DESCRIPTION">		>
	<t>		<name>DESCRIPTION</name>
			<t>
	The CB_NOTIFY operation is used by the server to		The CB_NOTIFY operation is used by the server to
	send notifications to clients about changes to		send notifications to clients about changes to
	delegated directories.		delegated directories.
	The registration of notifications for the directories		The registration of notifications for the directories
	occurs when the delegation is established using		occurs when the delegation is established using
	GET_DIR_DELEGATION.		GET_DIR_DELEGATION.
	These notifications are sent over the backchannel. The		These notifications are sent over the backchannel. The
	notification is sent once the original request has been		notification is sent once the original request has been
	processed on the server. The server will send an array of		processed on the server. The server will send an array of
	notifications for changes that might have occurred in the		notifications for changes that might have occurred in the
	directory. The notifications are sent as list of pairs of		directory. The notifications are sent as list of pairs of
	bitmaps and values.		bitmaps and values.
	See <xref target="fattr4" />		See <xref target="fattr4" format="default"/>
	for a description of how NFSv4.1 bitmaps work.		for a description of how NFSv4.1 bitmaps work.
	</t>		</t>
	<t>		<t>
	If the server has more notifications than can fit in		If the server has more notifications than can fit in
	the CB_COMPOUND request, it SHOULD send a sequence of		the CB_COMPOUND request, it <bcp14>SHOULD</bcp14> send a sequence of
	serial CB_COMPOUND requests so that the client's view		serial CB_COMPOUND requests so that the client's view
	of the directory does not become confused. For example, if the		of the directory does not become confused. For example, if the
	server indicates that a file named "foo" is added and that the		server indicates that a file named "foo" is added and that the
	file "foo" is removed, the order in which the client receives		file "foo" is removed, the order in which the client receives
	these notifications needs to be the same as the		these notifications needs to be the same as the
	order in which the corresponding operations occurred on the server.		order in which the corresponding operations occurred on the server.
	</t>		</t>
			<t>
	<t>
	If the client holding the delegation makes any		If the client holding the delegation makes any
	changes in the directory that cause files or sub-directories to		changes in the directory that cause files or sub-directories to
	be added or removed, the server will		be added or removed, the server will
	notify that client of the resulting change(s). If the		notify that client of the resulting change(s). If the
	client holding the delegation is making attribute		client holding the delegation is making attribute
	or cookie verifier changes only, the server does		or cookie verifier changes only, the server does
	not need to send notifications to that client.		not need to send notifications to that client.
	The server will send the following information for		The server will send the following information for
	each operation:		each operation:
	<list style="hanging">		</t>
	<t hangText="NOTIFY4_ADD_ENTRY"><vspace />		<dl newline="true" spacing="normal">
			<dt>NOTIFY4_ADD_ENTRY</dt>
			<dd>
	The server will send		The server will send
	information about the new directory entry being created along with the		information about the new directory entry being created along with the
	cookie for that entry. The entry information (data type		cookie for that entry. The entry information (data type
	notify_add4) includes the component name of the entry and		notify_add4) includes the component name of the entry and
	attributes. The server will send this type of entry when a		attributes. The server will send this type of entry when a
	file is actually being created, when an entry is being added		file is actually being created, when an entry is being added
	to a directory as a result of a rename across directories		to a directory as a result of a rename across directories
	(see below), and when a hard link is being created to an		(see below), and when a hard link is being created to an
	existing file. If this entry is added to the end of the		existing file. If this entry is added to the end of the
	directory, the server will set the nad_last_entry flag to		directory, the server will set the nad_last_entry flag to
	skipping to change at line 40941 ¶		skipping to change at line 40813 ¶
	of up to one element. If the array is of zero length, there		of up to one element. If the array is of zero length, there
	is no previous entry), along with its cookie. This is to		is no previous entry), along with its cookie. This is to
	help clients find the right location in their file name caches and		help clients find the right location in their file name caches and
	directory caches where this entry should be cached. If the		directory caches where this entry should be cached. If the
	new entry's cookie is available, it will be in		new entry's cookie is available, it will be in
	the nad_new_entry_cookie (another variable-length array of up to		the nad_new_entry_cookie (another variable-length array of up to
	one element) field. If the addition of the entry causes another		one element) field. If the addition of the entry causes another
	entry to be deleted (which can only happen in the rename		entry to be deleted (which can only happen in the rename
	case) atomically with the addition, then information on		case) atomically with the addition, then information on
	this entry is reported in nad_old_entry.		this entry is reported in nad_old_entry.
	</t>		</dd>
	<t hangText="NOTIFY4_REMOVE_ENTRY"><vspace />		<dt>NOTIFY4_REMOVE_ENTRY</dt>
			<dd>
	The server will send information about the directory entry		The server will send information about the directory entry
	being deleted. The server will also send the cookie value		being deleted. The server will also send the cookie value
	for the deleted entry so that clients can get to the cached		for the deleted entry so that clients can get to the cached
	information for this entry.		information for this entry.
	</t>		</dd>
	<t hangText="NOTIFY4_RENAME_ENTRY"><vspace />		<dt>NOTIFY4_RENAME_ENTRY</dt>
			<dd>
	The server will send information about both		The server will send information about both
	the old entry and the new entry. This includes the name and		the old entry and the new entry. This includes the name and
	attributes for each entry. In addition, if the rename		attributes for each entry. In addition, if the rename
	causes the deletion of an entry (i.e., the case of a file		causes the deletion of an entry (i.e., the case of a file
	renamed over), then this is reported in		renamed over), then this is reported in
	nrn_new_new_entry.nad_old_entry.		nrn_new_new_entry.nad_old_entry.
	This notification is only sent if		This notification is only sent if
	both entries are in the same directory. If the rename is		both entries are in the same directory. If the rename is
	across directories, the server will send a remove		across directories, the server will send a remove
	notification to one directory and an add notification to the		notification to one directory and an add notification to the
	other directory, assuming both have a directory delegation.		other directory, assuming both have a directory delegation.
	</t>		</dd>
	<t		<dt>NOTIFY4_CHANGE_CHILD_ATTRS/NOTIFY4_CHANGE_DIR_ATTRS</dt>
	hangText="NOTIFY4_CHANGE_CHILD_ATTRS/NOTIFY4_CHANGE_DIR_ATTRS"><vspace		<dd>
	/>
	The client will use the attribute		The client will use the attribute
	mask to inform the server of attributes for which it wants to		mask to inform the server of attributes for which it wants to
	receive notifications. This change notification can be		receive notifications. This change notification can be
	requested for changes to the attributes of the directory		requested for changes to the attributes of the directory
	as well as changes to any file's attributes in the directory by		as well as changes to any file's attributes in the directory by
	using two separate attribute masks. The client cannot ask		using two separate attribute masks. The client cannot ask
	for change attribute notification for a specific file. One attribute		for change attribute notification for a specific file. One attribute
	mask covers all the files in the directory. Upon any		mask covers all the files in the directory. Upon any
	attribute change, the server will send back the values of		attribute change, the server will send back the values of
	changed attributes. Notifications might not make sense for		changed attributes. Notifications might not make sense for
	some file system-wide attributes, and it is up to the server to		some file system-wide attributes, and it is up to the server to
	decide which subset it wants to support. The client can		decide which subset it wants to support. The client can
	negotiate the frequency of attribute notifications by letting		negotiate the frequency of attribute notifications by letting
	the server know how often it wants to be notified of an		the server know how often it wants to be notified of an
	attribute change. The server will return supported		attribute change. The server will return supported
	notification frequencies or an indication that no		notification frequencies or an indication that no
	notification is permitted for directory or child attributes		notification is permitted for directory or child attributes
	by setting the dir_notif_delay and		by setting the dir_notif_delay and
	dir_entry_notif_delay attributes, respectively.		dir_entry_notif_delay attributes, respectively.
	</t>		</dd>
	<t hangText="NOTIFY4_CHANGE_COOKIE_VERIFIER"><vspace />		<dt>NOTIFY4_CHANGE_COOKIE_VERIFIER</dt>
			<dd>
	If the cookie verifier changes while		If the cookie verifier changes while
	a client is holding a delegation, the server will notify the		a client is holding a delegation, the server will notify the
	client so that it can invalidate its cookies and re-send a		client so that it can invalidate its cookies and re-send a
	READDIR to get the new set of cookies.		READDIR to get the new set of cookies.
	</t>		</dd>
	</list>		</dl>
	</t>		</section>
	</section>		</section>
	</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->
	<!-- Copyright (C) The IETF Trust (2007-2008) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="OP_CB_PUSH_DELEG"
	title="Operation 7: CB_PUSH_DELEG - Offer Previously Requested Delegati
	on to Client" >
	<section toc="exclude" anchor="OP_CB_PUSH_DELEG_ARGUMENT" title="ARGUMENT">		<section anchor="OP_CB_PUSH_DELEG" numbered="true" toc="default">
	<figure>		<name>Operation 7: CB_PUSH_DELEG - Offer Previously Requested Delegation
	<artwork>		to Client</name>
			<section toc="exclude" anchor="OP_CB_PUSH_DELEG_ARGUMENT" numbered="true
			">
			<name>ARGUMENT</name>
			<sourcecode type="xdr"><![CDATA[
	struct CB_PUSH_DELEG4args {		struct CB_PUSH_DELEG4args {
	nfs_fh4 cpda_fh;		nfs_fh4 cpda_fh;
	open_delegation4 cpda_delegation;		open_delegation4 cpda_delegation;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_PUSH_DELEG_RESULT" numbered="true">
	<section toc="exclude" anchor="OP_CB_PUSH_DELEG_RESULT" title="RESULT">		<name>RESULT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct CB_PUSH_DELEG4res {		struct CB_PUSH_DELEG4res {
	nfsstat4 cpdr_status;		nfsstat4 cpdr_status;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_PUSH_DELEG_DESCRIPTION" numbered="t
	<section toc="exclude" anchor="OP_CB_PUSH_DELEG_DESCRIPTION" title="DESCRIPTIO		rue">
	N">		<name>DESCRIPTION</name>
	<t>		<t>
	CB_PUSH_DELEG is used by the server both to signal to the		CB_PUSH_DELEG is used by the server both to signal to the
	client that the delegation it wants (previously indicated		client that the delegation it wants (previously indicated
	via a want established from an		via a want established from an
	OPEN or WANT_DELEGATION operation) is available and to		OPEN or WANT_DELEGATION operation) is available and to
	simultaneously offer the delegation to the client. The client		simultaneously offer the delegation to the client. The client
	has the choice of accepting the delegation by returning		has the choice of accepting the delegation by returning
	NFS4_OK to the server, delaying the decision to accept the		NFS4_OK to the server, delaying the decision to accept the
	offered delegation by returning NFS4ERR_DELAY,		offered delegation by returning NFS4ERR_DELAY,
	or permanently rejecting the offer of the		or permanently rejecting the offer of the
	delegation by returning NFS4ERR_REJECT_DELEG.		delegation by returning NFS4ERR_REJECT_DELEG.
	When a delegation is rejected in this fashion, the want		When a delegation is rejected in this fashion, the want
	previously established is permanently deleted and the delegation		previously established is permanently deleted and the delegation
	is subject to acquisition by another client.		is subject to acquisition by another client.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_CB_PUSH_DELEG_IMPLEMENTATION" title="IMPLEME		<section toc="exclude" anchor="OP_CB_PUSH_DELEG_IMPLEMENTATION" numbered
	NTATION">		="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	If the client does return NFS4ERR_DELAY		If the client does return NFS4ERR_DELAY
	and there is a conflicting delegation request, the server MAY		and there is a conflicting delegation request, the server <bcp14>MAY</bcp 14>
	process it at the expense of the client that returned		process it at the expense of the client that returned
	NFS4ERR_DELAY. The client's want will not be cancelled, but		NFS4ERR_DELAY. The client's want will not be cancelled, but
	MAY be processed behind other delegation requests or registered		<bcp14>MAY</bcp14> be processed behind other delegation requests or regis tered
	wants.		wants.
	</t>		</t>
	<t>		<t>
	When a client returns a status other than NFS4_OK, NFS4ERR_DELAY,		When a client returns a status other than NFS4_OK, NFS4ERR_DELAY,
	or NFS4ERR_REJECT_DELAY, the want remains pending, although		or NFS4ERR_REJECT_DELAY, the want remains pending, although
	servers may decide to cancel the want by sending a CB_WANTS_CANCELLED.		servers may decide to cancel the want by sending a CB_WANTS_CANCELLED.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_CB_RECALL_ANY" numbered="true" toc="default">
	$ -->		<name>Operation 8: CB_RECALL_ANY - Keep Any N Recallable Objects</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_CB_RECALL_ANY_ARGUMENT" numbered="true
	<!-- Copyright (C) The Internet Society (2006) -->		">
	<section anchor="OP_CB_RECALL_ANY" title="Operation 8: CB_RECALL_ANY - Keep Any		<name>ARGUMENT</name>
	N Recallable Objects" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_CB_RECALL_ANY_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	const RCA4_TYPE_MASK_RDATA_DLG = 0;		const RCA4_TYPE_MASK_RDATA_DLG = 0;
	const RCA4_TYPE_MASK_WDATA_DLG = 1;		const RCA4_TYPE_MASK_WDATA_DLG = 1;
	const RCA4_TYPE_MASK_DIR_DLG = 2;		const RCA4_TYPE_MASK_DIR_DLG = 2;
	const RCA4_TYPE_MASK_FILE_LAYOUT = 3;		const RCA4_TYPE_MASK_FILE_LAYOUT = 3;
	const RCA4_TYPE_MASK_BLK_LAYOUT = 4;		const RCA4_TYPE_MASK_BLK_LAYOUT = 4;
	const RCA4_TYPE_MASK_OBJ_LAYOUT_MIN = 8;		const RCA4_TYPE_MASK_OBJ_LAYOUT_MIN = 8;
	const RCA4_TYPE_MASK_OBJ_LAYOUT_MAX = 9;		const RCA4_TYPE_MASK_OBJ_LAYOUT_MAX = 9;
	const RCA4_TYPE_MASK_OTHER_LAYOUT_MIN = 12;		const RCA4_TYPE_MASK_OTHER_LAYOUT_MIN = 12;
	const RCA4_TYPE_MASK_OTHER_LAYOUT_MAX = 15;		const RCA4_TYPE_MASK_OTHER_LAYOUT_MAX = 15;
	struct CB_RECALL_ANY4args {		struct CB_RECALL_ANY4args {
	uint32_t craa_objects_to_keep;		uint32_t craa_objects_to_keep;
	bitmap4 craa_type_mask;		bitmap4 craa_type_mask;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_RECALL_ANY_RESULT" numbered="true">
	<section toc="exclude" anchor="OP_CB_RECALL_ANY_RESULT" title="RESULT">		<name>RESULT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct CB_RECALL_ANY4res {		struct CB_RECALL_ANY4res {
	nfsstat4 crar_status;		nfsstat4 crar_status;
	};		};
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_RECALL_ANY_DESCRIPTION" numbered="t
	<section toc="exclude" anchor="OP_CB_RECALL_ANY_DESCRIPTION" title="DESCRIPTIO		rue">
	N">		<name>DESCRIPTION</name>
	<t>		<t>
	The server may decide that it cannot hold all of the state for		The server may decide that it cannot hold all of the state for
	recallable objects, such as delegations and layouts, without		recallable objects, such as delegations and layouts, without
	running out of resources. In such a case, while not optimal,		running out of resources. In such a case, while not optimal,
	the server is free to recall individual objects to reduce the load.		the server is free to recall individual objects to reduce the load.
	</t>		</t>
	<t>		<t>
	Because the general purpose of such recallable objects as		Because the general purpose of such recallable objects as
	delegations is to eliminate client interaction with the server,		delegations is to eliminate client interaction with the server,
	the server cannot interpret lack of recent use as indicating		the server cannot interpret lack of recent use as indicating
	that the object is no longer useful. The absence of visible		that the object is no longer useful. The absence of visible
	use is consistent with a delegation keeping potential operations		use is consistent with a delegation keeping potential operations
	from being sent to the server. In the case of layouts, while it		from being sent to the server. In the case of layouts, while it
	is true that the usefulness of a layout		is true that the usefulness of a layout
	is indicated by the use of the layout when storage devices receive		is indicated by the use of the layout when storage devices receive
	I/O requests, because there is no mandate that a storage		I/O requests, because there is no mandate that a storage
	device indicate to the metadata server any past or		device indicate to the metadata server any past or
	present use of a layout, the metadata server is not likely to know		present use of a layout, the metadata server is not likely to know
	which layouts are good candidates to recall in response to		which layouts are good candidates to recall in response to
	low resources.		low resources.
	</t>		</t>
	<t>		<t>
	In order to implement an effective reclaim scheme for such		In order to implement an effective reclaim scheme for such
	objects, the server's knowledge of available resources must be		objects, the server's knowledge of available resources must be
	used to determine when objects must be recalled with the		used to determine when objects must be recalled with the
	clients selecting the actual objects to be returned.		clients selecting the actual objects to be returned.
	</t>		</t>
	<t>		<t>
	Server implementations may differ in their resource allocation		Server implementations may differ in their resource allocation
	requirements. For example, one server may share resources among		requirements. For example, one server may share resources among
	all classes of recallable objects, whereas another may use		all classes of recallable objects, whereas another may use
	separate resource pools for layouts and for delegations, or		separate resource pools for layouts and for delegations, or
	further separate resources by types of delegations.		further separate resources by types of delegations.
	</t>		</t>
	<t>		<t>
	When a given resource pool is over-utilized, the server can		When a given resource pool is over-utilized, the server can
	send a CB_RECALL_ANY to clients holding recallable objects of		send a CB_RECALL_ANY to clients holding recallable objects of
	the types involved, allowing it to keep a certain number of		the types involved, allowing it to keep a certain number of
	such objects and return any excess. A mask specifies which		such objects and return any excess. A mask specifies which
	types of objects are to be limited. The client chooses, based		types of objects are to be limited. The client chooses, based
	on its own knowledge of current usefulness, which of the objects		on its own knowledge of current usefulness, which of the objects
	in that class should be returned.		in that class should be returned.
	</t>		</t>
	<t>		<t>
	A number of bits are defined. For some of these, ranges		A number of bits are defined. For some of these, ranges
	are defined and it is up to the definition of the storage		are defined and it is up to the definition of the storage
	protocol to specify how these are to be used. There are ranges		protocol to specify how these are to be used. There are ranges
	reserved for object-based storage		reserved for object-based storage
	protocols and for other experimental storage		protocols and for other experimental storage
	protocols. An RFC defining such a storage protocol needs to		protocols. An RFC defining such a storage protocol needs to
	specify how particular bits within its range are to be used.		specify how particular bits within its range are to be used.
	For example, it may specify a mapping between attributes of		For example, it may specify a mapping between attributes of
	the layout (read vs. write, size of area) and the bit to be		the layout (read vs. write, size of area) and the bit to be
	used, or it may define a field in the layout where the associated		used, or it may define a field in the layout where the associated
	bit position is made available by the server to the client.		bit position is made available by the server to the client.
	<list style='hanging'>		</t>
	<t hangText='RCA4_TYPE_MASK_RDATA_DLG'>		<dl newline="true" spacing="normal">
	</t>		<dt>RCA4_TYPE_MASK_RDATA_DLG</dt>
	<t>		<dd>
	The client is to return OPEN_DELEGATE_READ delegations on		The client is to return OPEN_DELEGATE_READ delegations on
	non-directory file objects.		non-directory file objects.
	</t>		</dd>
			<dt>RCA4_TYPE_MASK_WDATA_DLG</dt>
	<t hangText='RCA4_TYPE_MASK_WDATA_DLG'>		<dd>
	</t>
	<t>
	The client is to return OPEN_DELEGATE_WRITE delegations on		The client is to return OPEN_DELEGATE_WRITE delegations on
	regular file objects.		regular file objects.
	</t>		</dd>
			<dt>RCA4_TYPE_MASK_DIR_DLG</dt>
	<t hangText='RCA4_TYPE_MASK_DIR_DLG'>		<dd>
	</t>
	<t>
	The client is to return directory delegations.		The client is to return directory delegations.
	</t>		</dd>
			<dt>RCA4_TYPE_MASK_FILE_LAYOUT</dt>
	<t hangText='RCA4_TYPE_MASK_FILE_LAYOUT'>		<dd>
	</t>
	<t>
	The client is to return layouts of type LAYOUT4_NFSV4_1_FILES.		The client is to return layouts of type LAYOUT4_NFSV4_1_FILES.
	</t>		</dd>
	<t hangText='RCA4_TYPE_MASK_BLK_LAYOUT'>		<dt>RCA4_TYPE_MASK_BLK_LAYOUT</dt>
	</t>		<dd>
	<t>		See <xref target="RFC5663" format="default"/> for a description.
	See <xref target='RFC5663' /> for a description.
	</t>
	<t hangText='RCA4_TYPE_MASK_OBJ_LAYOUT_MIN to RCA4_TYPE_MASK_OBJ_LAYOUT_MA		</dd>
	X'>		<dt>RCA4_TYPE_MASK_OBJ_LAYOUT_MIN to RCA4_TYPE_MASK_OBJ_LAYOUT_MAX</
	</t>		dt>
	<t>		<dd>
	See <xref target='RFC5664' /> for a description.		See <xref target="RFC5664" format="default"/> for a description.
	</t>		</dd>
	<t hangText='RCA4_TYPE_MASK_OTHER_LAYOUT_MIN to RCA4_TYPE_MASK_OTHER_LAYOU		<dt>RCA4_TYPE_MASK_OTHER_LAYOUT_MIN to RCA4_TYPE_MASK_OTHER_LAYOUT_M
	T_MAX'>		AX</dt>
	</t>		<dd>
	<t>
	This range is reserved for telling the client to recall		This range is reserved for telling the client to recall
	layouts of experimental		layouts of experimental
	or site-specific layout types (see <xref		or site-specific layout types (see <xref target="layouttype4" format="de
	target='layouttype4'/>).		fault"/>).
	</t>
	</list>
	</t>		</dd>
	<t>		</dl>
			<t>
	When a bit is set in the type mask that corresponds		When a bit is set in the type mask that corresponds
	to an undefined type of recallable object,		to an undefined type of recallable object,
	NFS4ERR_INVAL MUST be returned. When a bit is set		NFS4ERR_INVAL <bcp14>MUST</bcp14> be returned. When a bit is set
	that corresponds to a defined type of object but		that corresponds to a defined type of object but
	the client does not support an object of the type,		the client does not support an object of the type,
	NFS4ERR_INVAL MUST NOT be returned. Future minor		NFS4ERR_INVAL <bcp14>MUST NOT</bcp14> be returned. Future minor
	versions of NFSv4 may expand the set of valid type		versions of NFSv4 may expand the set of valid type
	mask bits.		mask bits.
	</t>		</t>
	<t>		<t>
	CB_RECALL_ANY specifies a count of objects that the client may		CB_RECALL_ANY specifies a count of objects that the client may
	keep as opposed to a count that the client must return. This		keep as opposed to a count that the client must return. This
	is to avoid a potential race between a CB_RECALL_ANY that had a		is to avoid a potential race between a CB_RECALL_ANY that had a
	count of objects to free with a set of client-originated		count of objects to free with a set of client-originated
	operations to return layouts or delegations. As a result of the		operations to return layouts or delegations. As a result of the
	race, the client and server would have differing ideas as to how		race, the client and server would have differing ideas as to how
	many objects to return. Hence, the client could mistakenly free		many objects to return. Hence, the client could mistakenly free
	too many.		too many.
	</t>		</t>
	<t>		<t>
	If resource demands prompt it, the server may send another		If resource demands prompt it, the server may send another
	CB_RECALL_ANY with a lower count, even if it has not yet received		CB_RECALL_ANY with a lower count, even if it has not yet received
	an acknowledgment from the client for a previous CB_RECALL_ANY		an acknowledgment from the client for a previous CB_RECALL_ANY
	with the same type mask. Although the possibility exists that		with the same type mask. Although the possibility exists that
	these will be received by the client in an order different from		these will be received by the client in an order different from
	the order in which they were sent, any such permutation of		the order in which they were sent, any such permutation of
	the callback stream is harmless. It is the job of the client		the callback stream is harmless. It is the job of the client
	to bring down the size of the recallable object set in line		to bring down the size of the recallable object set in line
	with each CB_RECALL_ANY received, and until that obligation is		with each CB_RECALL_ANY received, and until that obligation is
	met, it cannot be cancelled or modified by any subsequent		met, it cannot be cancelled or modified by any subsequent
	CB_RECALL_ANY for the same type mask. Thus, if the server		CB_RECALL_ANY for the same type mask. Thus, if the server
	sends two CB_RECALL_ANYs, the effect will be the same as		sends two CB_RECALL_ANYs, the effect will be the same as
	if the lower count was sent, whatever the order of recall		if the lower count was sent, whatever the order of recall
	receipt. Note that this means that a server may not cancel		receipt. Note that this means that a server may not cancel
	the effect of a CB_RECALL_ANY by sending another recall with		the effect of a CB_RECALL_ANY by sending another recall with
	a higher count. When a CB_RECALL_ANY is received and the		a higher count. When a CB_RECALL_ANY is received and the
	count is already within the limit set or is above a limit		count is already within the limit set or is above a limit
	that the client is working to get down to, that callback has no		that the client is working to get down to, that callback has no
	effect.		effect.
	</t>		</t>
	<t>		<t>
	Servers are generally free to deny recallable objects		Servers are generally free to deny recallable objects
	when insufficient resources are available. Note that the		when insufficient resources are available. Note that the
	effect of such a policy is implicitly to give precedence to		effect of such a policy is implicitly to give precedence to
	existing objects relative to requested ones, with the result		existing objects relative to requested ones, with the result
	that resources might not be optimally used. To prevent this,		that resources might not be optimally used. To prevent this,
	servers are well advised to make the point at which they start		servers are well advised to make the point at which they start
	sending CB_RECALL_ANY callbacks somewhat below that at which they		sending CB_RECALL_ANY callbacks somewhat below that at which they
	cease to give out new delegations and layouts. This allows the		cease to give out new delegations and layouts. This allows the
	client to purge its less-used objects whenever appropriate and		client to purge its less-used objects whenever appropriate and
	so continue to have its subsequent requests given new resources		so continue to have its subsequent requests given new resources
	freed up by object returns.		freed up by object returns.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_CB_RECALL_ANY_IMPLEMENTATION" title="IMPLEME		<section toc="exclude" anchor="OP_CB_RECALL_ANY_IMPLEMENTATION" numbered
	NTATION">		="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	The client can choose to return any type of object specified		The client can choose to return any type of object specified
	by the mask. If a server wishes to limit the use of objects of a		by the mask. If a server wishes to limit the use of objects of a
	specific type, it should only specify that type in the mask		specific type, it should only specify that type in the mask
	it sends. Should the client fail to return requested objects, it is		it sends. Should the client fail to return requested objects, it is
	up to the server to handle this situation, typically by sending		up to the server to handle this situation, typically by sending
	specific recalls (i.e., sending CB_RECALL operations)		specific recalls (i.e., sending CB_RECALL operations)
	to properly limit resource usage. The server		to properly limit resource usage. The server
	should give the client enough time to return objects before		should give the client enough time to return objects before
	proceeding to specific recalls. This time should not be less		proceeding to specific recalls. This time should not be less
	than the lease period.		than the lease period.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_CB_RECALLABLE_OBJ_AVAIL" numbered="true" toc="default">
	$ -->		<name>Operation 9: CB_RECALLABLE_OBJ_AVAIL - Signal Resources for Recall
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		able Objects</name>
	<!-- Copyright (C) The Internet Society (2006) -->		<section toc="exclude" anchor="OP_CB_RECALLABLE_OBJ_AVAIL_ARGUMENT" numb
	<section anchor="OP_CB_RECALLABLE_OBJ_AVAIL"		ered="true">
	title="Operation 9: CB_RECALLABLE_OBJ_AVAIL - Signal Resources for Reca		<name>ARGUMENT</name>
	llable Objects" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_CB_RECALLABLE_OBJ_AVAIL_ARGUMENT" title="ARG
	UMENT">
	<figure>
	<artwork>
	typedef CB_RECALL_ANY4args CB_RECALLABLE_OBJ_AVAIL4args;		typedef CB_RECALL_ANY4args CB_RECALLABLE_OBJ_AVAIL4args;
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_CB_RECALLABLE_OBJ_AVAIL_RESULT" number
	</section>		ed="true">
	<section toc="exclude" anchor="OP_CB_RECALLABLE_OBJ_AVAIL_RESULT" title="RESUL		<name>RESULT</name>
	T">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct CB_RECALLABLE_OBJ_AVAIL4res {		struct CB_RECALLABLE_OBJ_AVAIL4res {
	nfsstat4 croa_status;		nfsstat4 croa_status;
	};		};
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_CB_RECALLABLE_OBJ_AVAIL_DESCRIPTION" n
	</section>		umbered="true">
	<section toc="exclude" anchor="OP_CB_RECALLABLE_OBJ_AVAIL_DESCRIPTION" title="		<name>DESCRIPTION</name>
	DESCRIPTION">		<t>
	<t>
	CB_RECALLABLE_OBJ_AVAIL is used by the server to signal the		CB_RECALLABLE_OBJ_AVAIL is used by the server to signal the
	client that the server has resources to grant recallable		client that the server has resources to grant recallable
	objects that might previously have been denied by OPEN,		objects that might previously have been denied by OPEN,
	WANT_DELEGATION, GET_DIR_DELEG, or LAYOUTGET.		WANT_DELEGATION, GET_DIR_DELEG, or LAYOUTGET.
	</t>		</t>
	<t>		<t>
	The argument craa_objects_to_keep means the total number of		The argument craa_objects_to_keep means the total number of
	recallable objects of the types indicated in the argument		recallable objects of the types indicated in the argument
	type_mask that the server believes it can allow the client to		type_mask that the server believes it can allow the client to
	have, including the number of such objects the client already		have, including the number of such objects the client already
	has. A client that tries to acquire more recallable objects		has. A client that tries to acquire more recallable objects
	than the server informs it can have runs the risk of having		than the server informs it can have runs the risk of having
	objects recalled.		objects recalled.
	</t>		</t>
	<t>		<t>
	The server is not obligated to reserve the		The server is not obligated to reserve the
	difference between the number of the objects		difference between the number of the objects
	the client currently has and the value of		the client currently has and the value of
	craa_objects_to_keep, nor does delaying the reply		craa_objects_to_keep, nor does delaying the reply
	to CB_RECALLABLE_OBJ_AVAIL prevent the server		to CB_RECALLABLE_OBJ_AVAIL prevent the server
	from using the resources of the recallable objects		from using the resources of the recallable objects
	for another purpose. Indeed, if a client responds		for another purpose. Indeed, if a client responds
	slowly to CB_RECALLABLE_OBJ_AVAIL, the server might		slowly to CB_RECALLABLE_OBJ_AVAIL, the server might
	interpret the client as having reduced capability		interpret the client as having reduced capability
	to manage recallable objects, and so cancel		to manage recallable objects, and so cancel
	or reduce any reservation it is maintaining on behalf		or reduce any reservation it is maintaining on behalf
	of the client.		of the client.
	Thus, if the client desires to acquire more		Thus, if the client desires to acquire more
	recallable objects, it needs to reply quickly		recallable objects, it needs to reply quickly
	to CB_RECALLABLE_OBJ_AVAIL, and then send the		to CB_RECALLABLE_OBJ_AVAIL, and then send the
	appropriate operations to acquire recallable		appropriate operations to acquire recallable
	objects.		objects.
	</t>		</t>
	</section>		</section>
			</section>
	</section>		<section anchor="OP_CB_RECALL_SLOT" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 10: CB_RECALL_SLOT - Change Flow Control Limits</name>
	$ -->		<section toc="exclude" anchor="OP_CB_RECALL_SLOT_ARGUMENT" numbered="tru
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		e">
	<!-- Copyright (C) The Internet Society (2006) -->		<name>ARGUMENT</name>
	<section anchor="OP_CB_RECALL_SLOT" title="Operation 10: CB_RECALL_SLOT - Change		<sourcecode type="xdr"><![CDATA[
	Flow Control Limits" >
	<section toc="exclude" anchor="OP_CB_RECALL_SLOT_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct CB_RECALL_SLOT4args {		struct CB_RECALL_SLOT4args {
	slotid4 rsa_target_highest_slotid;		slotid4 rsa_target_highest_slotid;
	};		};
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_CB_RECALL_SLOT_RESULT" numbered="true"
	</section>		>
	<section toc="exclude" anchor="OP_CB_RECALL_SLOT_RESULT" title="RESULT">		<name>RESULT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct CB_RECALL_SLOT4res {		struct CB_RECALL_SLOT4res {
	nfsstat4 rsr_status;		nfsstat4 rsr_status;
	};		};
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_CB_RECALL_SLOT_DESCRIPTION" numbered="
	</section>		true">
	<section toc="exclude" anchor="OP_CB_RECALL_SLOT_DESCRIPTION" title="DESCRIPTI		<name>DESCRIPTION</name>
	ON">		<t>
	<t>
	The CB_RECALL_SLOT operation requests the client to		The CB_RECALL_SLOT operation requests the client to
	return session slots, and if applicable, transport		return session slots, and if applicable, transport
	credits (e.g., RDMA credits for connections associated with		credits (e.g., RDMA credits for connections associated with
	the operations channel) of the session's fore channel.		the operations channel) of the session's fore channel.
	CB_RECALL_SLOT specifies		CB_RECALL_SLOT specifies
	rsa_target_highest_slotid, the value of the target highest slot ID the ser ver wants		rsa_target_highest_slotid, the value of the target highest slot ID the ser ver wants
	for the session. The client MUST then progress toward reducing		for the session. The client <bcp14>MUST</bcp14> then progress toward reduc ing
	the session's highest slot ID to the target value.		the session's highest slot ID to the target value.
	</t>		</t>
	<t>		<t>
	If the session has only non-RDMA connections associated with its		If the session has only non-RDMA connections associated with its
	operations channel, then the client need only wait		operations channel, then the client need only wait
	for all outstanding requests with a slot ID >		for all outstanding requests with a slot ID &gt;
	rsa_target_highest_slotid to complete, then send		rsa_target_highest_slotid to complete, then send
	a single COMPOUND consisting of a single SEQUENCE operation,		a single COMPOUND consisting of a single SEQUENCE operation,
	with the sa_highestslot field set to rsa_target_highest_slotid.		with the sa_highestslot field set to rsa_target_highest_slotid.
	If there are RDMA-based connections associated with		If there are RDMA-based connections associated with
	operation channel, then the client needs to also		operation channel, then the client needs to also
	send enough zero-length "RDMA Send" messages to take the total		send enough zero-length "RDMA Send" messages to take the total
	<!-- Please leave this use of "Send" capitalized in order to denote
	an artifact particular to RDMA-based communication. Thanks. -->
	RDMA credit count to rsa_target_highest_slotid + 1 or below.		RDMA credit count to rsa_target_highest_slotid + 1 or below.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_CB_RECALL_SLOT_IMPLEMENTATION" title="IMPLEM		<section toc="exclude" anchor="OP_CB_RECALL_SLOT_IMPLEMENTATION" numbere
	ENTATION">		d="true">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	If the client fails to reduce highest slot it has on the fore channel		If the client fails to reduce highest slot it has on the fore channel
	to what the server requests, the server can force the issue		to what the server requests, the server can force the issue
	by asserting flow control on the receive side of		by asserting flow control on the receive side of
	all connections bound to the fore channel, and then		all connections bound to the fore channel, and then
	finish servicing all outstanding requests that are		finish servicing all outstanding requests that are
	in slots greater than rsa_target_highest_slotid. Once that		in slots greater than rsa_target_highest_slotid. Once that
	is done, the server can then open the flow control, and any time		is done, the server can then open the flow control, and any time
	the client sends a new request on a slot greater than		the client sends a new request on a slot greater than
	rsa_target_highest_slotid, the server can return NFS4ERR_BADSLOT.		rsa_target_highest_slotid, the server can return NFS4ERR_BADSLOT.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_CB_SEQUENCE" numbered="true" toc="default">
	$ -->		<name>Operation 11: CB_SEQUENCE - Supply Backchannel Sequencing and Cont
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		rol</name>
	<!-- Copyright (C) The Internet Society (2006) -->		<section toc="exclude" anchor="OP_CB_SEQUENCE_ARGUMENT" numbered="true">
	<section anchor="OP_CB_SEQUENCE" title="Operation 11: CB_SEQUENCE - Supply Backc		<name>ARGUMENT</name>
	hannel Sequencing and Control" >		<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_CB_SEQUENCE_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	struct referring_call4 {		struct referring_call4 {
	sequenceid4 rc_sequenceid;		sequenceid4 rc_sequenceid;
	slotid4 rc_slotid;		slotid4 rc_slotid;
	};		};
	struct referring_call_list4 {		struct referring_call_list4 {
	sessionid4 rcl_sessionid;		sessionid4 rcl_sessionid;
	referring_call4 rcl_referring_calls&lt;>;		referring_call4 rcl_referring_calls<>;
	};		};
	struct CB_SEQUENCE4args {		struct CB_SEQUENCE4args {
	sessionid4 csa_sessionid;		sessionid4 csa_sessionid;
	sequenceid4 csa_sequenceid;		sequenceid4 csa_sequenceid;
	slotid4 csa_slotid;		slotid4 csa_slotid;
	slotid4 csa_highest_slotid;		slotid4 csa_highest_slotid;
	bool csa_cachethis;		bool csa_cachethis;
	referring_call_list4 csa_referring_call_lists&lt;>;		referring_call_list4 csa_referring_call_lists<>;
	};		};
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_CB_SEQUENCE_RESULT" numbered="true">
	</section>		<name>RESULT</name>
	<section toc="exclude" anchor="OP_CB_SEQUENCE_RESULT" title="RESULT">		<sourcecode type="xdr"><![CDATA[
	<figure>
	<artwork>
	struct CB_SEQUENCE4resok {		struct CB_SEQUENCE4resok {
	sessionid4 csr_sessionid;		sessionid4 csr_sessionid;
	sequenceid4 csr_sequenceid;		sequenceid4 csr_sequenceid;
	slotid4 csr_slotid;		slotid4 csr_slotid;
	slotid4 csr_highest_slotid;		slotid4 csr_highest_slotid;
	slotid4 csr_target_highest_slotid;		slotid4 csr_target_highest_slotid;
	};		};
	union CB_SEQUENCE4res switch (nfsstat4 csr_status) {		union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
	case NFS4_OK:		case NFS4_OK:
	CB_SEQUENCE4resok csr_resok4;		CB_SEQUENCE4resok csr_resok4;
	default:		default:
	void;		void;
	};		};
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_CB_SEQUENCE_DESCRIPTION" numbered="tru
	</section>		e">
	<section toc="exclude" anchor="OP_CB_SEQUENCE_DESCRIPTION" title="DESCRIPTION"		<name>DESCRIPTION</name>
	>		<t>
	<t>
	The CB_SEQUENCE operation is used to manage operational accounting		The CB_SEQUENCE operation is used to manage operational accounting
	for the backchannel of the session on which a request is		for the backchannel of the session on which a request is
	sent. The contents include the session ID to which this		sent. The contents include the session ID to which this
	request belongs, the slot ID and sequence ID used by the server to		request belongs, the slot ID and sequence ID used by the server to
	implement session request control and exactly once		implement session request control and exactly once
	semantics, and exchanged slot ID maxima that are used to adjust the		semantics, and exchanged slot ID maxima that are used to adjust the
	size of the reply cache. In each CB_COMPOUND request, CB_SEQUENCE		size of the reply cache. In each CB_COMPOUND request, CB_SEQUENCE
	MUST appear once and MUST be the first operation. The error		<bcp14>MUST</bcp14> appear once and <bcp14>MUST</bcp14> be the first opera
	NFS4ERR_SEQUENCE_POS MUST be returned when CB_SEQUENCE is found in		tion. The error
			NFS4ERR_SEQUENCE_POS <bcp14>MUST</bcp14> be returned when CB_SEQUENCE is f
			ound in
	any position in a CB_COMPOUND beyond the first. If any		any position in a CB_COMPOUND beyond the first. If any
	other operation is in the first position of CB_COMPOUND,		other operation is in the first position of CB_COMPOUND,
	NFS4ERR_OP_NOT_IN_SESSION MUST be returned.		NFS4ERR_OP_NOT_IN_SESSION <bcp14>MUST</bcp14> be returned.
	</t>		</t>
	<t>		<t>
	See <xref target="OP_SEQUENCE_DESCRIPTION"/> for a description of		See <xref target="OP_SEQUENCE_DESCRIPTION" format="default"/> for a descri
			ption of
	how slots are processed.		how slots are processed.
	</t>		</t>
	<t>		<t>
	If csa_cachethis is TRUE, then the server is requesting that		If csa_cachethis is TRUE, then the server is requesting that
	the client cache the reply in the callback reply cache. The client MUST		the client cache the reply in the callback reply cache. The client <bcp14>M
	cache the reply (see <xref target="optional_reply_caching" />).		UST</bcp14>
	</t>		cache the reply (see <xref target="optional_reply_caching" format="default"
	<t>		/>).
			</t>
			<t>
	The csa_referring_call_lists array is the list of COMPOUND		The csa_referring_call_lists array is the list of COMPOUND
	requests, identified by session ID, slot ID, and sequence ID. These		requests, identified by session ID, slot ID, and sequence ID. These
	are requests that the client previously sent to the server.		are requests that the client previously sent to the server.
	These previous requests created state that some operation(s)		These previous requests created state that some operation(s)
	in the same CB_COMPOUND as the csa_referring_call_lists are		in the same CB_COMPOUND as the csa_referring_call_lists are
	identifying.		identifying.
	A session ID is included because		A session ID is included because
	leased state is tied to a client ID, and a client ID can have		leased state is tied to a client ID, and a client ID can have
	multiple sessions. See		multiple sessions. See
	<xref target="sessions_callback_races" />.		<xref target="sessions_callback_races" format="default"/>.
	</t>		</t>
	<t>		<t>
	The value of the csa_sequenceid argument relative to		The value of the csa_sequenceid argument relative to
	the cached sequence ID on the slot falls into one		the cached sequence ID on the slot falls into one
	of three cases.		of three cases.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	If the difference between csa_sequenceid and		If the difference between csa_sequenceid and
	the client's cached sequence ID at the slot ID		the client's cached sequence ID at the slot ID
	is two (2) or more,		is two (2) or more,
	or if csa_sequenceid is less		or if csa_sequenceid is less
	than the cached sequence ID (accounting		than the cached sequence ID (accounting
	for wraparound of the unsigned sequence ID value),		for wraparound of the unsigned sequence ID value),
	then the client MUST return NFS4ERR_SEQ_MISORDERED.		then the client <bcp14>MUST</bcp14> return NFS4ERR_SEQ_MISORDERED.
	</t>		</li>
	<t>		<li>
	If csa_sequenceid and the cached sequence ID are the		If csa_sequenceid and the cached sequence ID are the
	same, this is a retry, and the client returns the		same, this is a retry, and the client returns the
	CB_COMPOUND request's cached reply.		CB_COMPOUND request's cached reply.
	</t>		</li>
	<t>		<li>
	If csa_sequenceid is one greater (accounting for		If csa_sequenceid is one greater (accounting for
	wraparound) than the cached sequence ID, then		wraparound) than the cached sequence ID, then
	this is a new request, and the slot's sequence		this is a new request, and the slot's sequence
	ID is incremented. The operations subsequent to		ID is incremented. The operations subsequent to
	CB_SEQUENCE, if any, are processed. If there are no		CB_SEQUENCE, if any, are processed. If there are no
	other operations, the only other effects are to		other operations, the only other effects are to
	cache the CB_SEQUENCE reply in the slot, maintain the		cache the CB_SEQUENCE reply in the slot, maintain the
	session's activity, and when the server receives the		session's activity, and when the server receives the
	CB_SEQUENCE reply, renew the lease of state		CB_SEQUENCE reply, renew the lease of state
	related to the client ID.		related to the client ID.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	If the server reuses a slot ID and sequence ID for		If the server reuses a slot ID and sequence ID for
	a completely different request, the client MAY		a completely different request, the client <bcp14>MAY</bcp14>
	treat the request as if it is a retry		treat the request as if it is a retry
	of what it has already executed. The client MAY however		of what it has already executed. The client <bcp14>MAY</bcp14> however
	detect the server's illegal reuse and return NFS4ERR_SEQ_FALSE_RETRY.		detect the server's illegal reuse and return NFS4ERR_SEQ_FALSE_RETRY.
	</t>		</t>
	<t>		<t>
	If CB_SEQUENCE returns an error, then the state of the slot (sequence ID,		If CB_SEQUENCE returns an error, then the state of the slot (sequence ID,
	cached reply) MUST NOT change.		cached reply) <bcp14>MUST NOT</bcp14> change.
	See <xref target="optional_reply_caching"/> for the conditions when the		See <xref target="optional_reply_caching" format="default"/> for the condit
			ions when the
	error NFS4ERR_RETRY_UNCACHED_REP might be returned.		error NFS4ERR_RETRY_UNCACHED_REP might be returned.
	</t>		</t>
	<t>		<t>
	The client returns two "highest_slotid" values:		The client returns two "highest_slotid" values:
	csr_highest_slotid and csr_target_highest_slotid. The		csr_highest_slotid and csr_target_highest_slotid. The
	former is the highest slot ID the client will accept		former is the highest slot ID the client will accept
	in a future CB_SEQUENCE operation, and SHOULD NOT be		in a future CB_SEQUENCE operation, and <bcp14>SHOULD NOT</bcp14> be
	less than the value of csa_highest_slotid (but see		less than the value of csa_highest_slotid (but see
	<xref target="Slot_Identifiers_and_Server_Reply_Cache"		<xref target="Slot_Identifiers_and_Server_Reply_Cache" format="default"/> f
	/> for an exception). The latter is the highest slot		or an exception). The latter is the highest slot
	ID the client would prefer the server use on a future		ID the client would prefer the server use on a future
	CB_SEQUENCE operation.		CB_SEQUENCE operation.
	</t>		</t>
	</section>		</section>
			</section>
	</section>		<section anchor="OP_CB_WANTS_CANCELLED" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 12: CB_WANTS_CANCELLED - Cancel Pending Delegation Wants
	$ -->		</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<section toc="exclude" anchor="OP_CB_WANTS_CANCELLED_ARGUMENT" numbered=
	<!-- Copyright (C) The Internet Society (2006) -->		"true">
	<section anchor="OP_CB_WANTS_CANCELLED"		<name>ARGUMENT</name>
	title="Operation 12: CB_WANTS_CANCELLED - Cancel Pending Delegation Wan		<sourcecode type="xdr"><![CDATA[
	ts " >
	<section toc="exclude" anchor="OP_CB_WANTS_CANCELLED_ARGUMENT" title="ARGUMENT
	">
	<figure>
	<artwork>
	struct CB_WANTS_CANCELLED4args {		struct CB_WANTS_CANCELLED4args {
	bool cwca_contended_wants_cancelled;		bool cwca_contended_wants_cancelled;
	bool cwca_resourced_wants_cancelled;		bool cwca_resourced_wants_cancelled;
	};		};
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_CB_WANTS_CANCELLED_RESULT" numbered="t
	</section>		rue">
	<section toc="exclude" anchor="OP_CB_WANTS_CANCELLED_RESULT" title="RESULT">		<name>RESULT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct CB_WANTS_CANCELLED4res {		struct CB_WANTS_CANCELLED4res {
	nfsstat4 cwcr_status;		nfsstat4 cwcr_status;
	};		};
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_CB_WANTS_CANCELLED_DESCRIPTION" number
	</section>		ed="true">
	<section toc="exclude" anchor="OP_CB_WANTS_CANCELLED_DESCRIPTION" title="DESCR		<name>DESCRIPTION</name>
	IPTION">		<t>
	<t>
	The CB_WANTS_CANCELLED operation is used to notify the client that		The CB_WANTS_CANCELLED operation is used to notify the client that
	some or all of the wants it registered for recallable delegations and layo uts		some or all of the wants it registered for recallable delegations and layo uts
	have been cancelled.		have been cancelled.
	</t>		</t>
	<t>		<t>
	If cwca_contended_wants_cancelled is TRUE, this indicates that		If cwca_contended_wants_cancelled is TRUE, this indicates that
	the server will not be pushing to the client any delegations		the server will not be pushing to the client any delegations
	that become available after contention passes.		that become available after contention passes.
	</t>		</t>
	<t>		<t>
	If cwca_resourced_wants_cancelled is TRUE, this indicates that		If cwca_resourced_wants_cancelled is TRUE, this indicates that
	the server will not notify the client when there are resources		the server will not notify the client when there are resources
	on the server to grant delegations or layouts.		on the server to grant delegations or layouts.
	</t>		</t>
	<t>		<t>
	After receiving a CB_WANTS_CANCELLED operation, the		After receiving a CB_WANTS_CANCELLED operation, the
	client is free to attempt to acquire the delegations or		client is free to attempt to acquire the delegations or
	layouts it was waiting for, and possibly re-register wants.		layouts it was waiting for, and possibly re-register wants.
	</t>		</t>
			</section>
	</section>		<section toc="exclude" anchor="OP_CB_WANTS_CANCELLED_IMPLEMENTATION" num
	<section toc="exclude" anchor="OP_CB_WANTS_CANCELLED_IMPLEMENTATION" title="IM		bered="true">
	PLEMENTATION">		<name>IMPLEMENTATION</name>
	<t>		<t>
	When a client has an OPEN, WANT_DELEGATION, or GET_DIR_DELEGATION request		When a client has an OPEN, WANT_DELEGATION, or GET_DIR_DELEGATION request
	outstanding, when a CB_WANTS_CANCELLED is sent, the server may need to		outstanding, when a CB_WANTS_CANCELLED is sent, the server may need to
	make clear to the client whether a promise to signal delegation availabili ty		make clear to the client whether a promise to signal delegation availabili ty
	happened before the CB_WANTS_CANCELLED and is thus covered by it, or after		happened before the CB_WANTS_CANCELLED and is thus covered by it, or after
	the CB_WANTS_CANCELLED in which case it was not covered by it. The server		the CB_WANTS_CANCELLED in which case it was not covered by it. The server
	can make this distinction by putting the appropriate requests into the		can make this distinction by putting the appropriate requests into the
	list of referring calls in the associated CB_SEQUENCE.		list of referring calls in the associated CB_SEQUENCE.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- Copyright (C) The Internet Society (2006) -->		<section anchor="OP_CB_NOTIFY_LOCK" numbered="true" toc="default">
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<name>Operation 13: CB_NOTIFY_LOCK - Notify Client of Possible Lock Avai
	<section anchor="OP_CB_NOTIFY_LOCK" title="Operation 13: CB_NOTIFY_LOCK - Notify		lability</name>
	Client of Possible Lock Availability" >		<section toc="exclude" anchor="OP_CB_NOTIFY_LOCK_ARGUMENT" numbered="tru
			e">
	<section toc="exclude" anchor="OP_CB_NOTIFY_LOCK_ARGUMENT" title="ARGUMENT">		<name>ARGUMENT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct CB_NOTIFY_LOCK4args {		struct CB_NOTIFY_LOCK4args {
	nfs_fh4 cnla_fh;		nfs_fh4 cnla_fh;
	lock_owner4 cnla_lock_owner;		lock_owner4 cnla_lock_owner;
	};		};
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_CB_NOTIFY_LOCK_RESULT" numbered="true"
	</section>		>
	<section toc="exclude" anchor="OP_CB_NOTIFY_LOCK_RESULT" title="RESULT">		<name>RESULT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct CB_NOTIFY_LOCK4res {		struct CB_NOTIFY_LOCK4res {
	nfsstat4 cnlr_status;		nfsstat4 cnlr_status;
	};		};
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_CB_NOTIFY_LOCK_DESCRIPTION" numbered="
	</section>		true">
	<section toc="exclude" anchor="OP_CB_NOTIFY_LOCK_DESCRIPTION" title="DESCRIPTI		<name>DESCRIPTION</name>
	ON">		<t>
	<t>
	The server can use this operation to indicate that a byte-range lock for t he given		The server can use this operation to indicate that a byte-range lock for t he given
	file and lock-owner, previously requested by the client via an unsuccessfu l		file and lock-owner, previously requested by the client via an unsuccessfu l
	LOCK operation, might be available.		LOCK operation, might be available.
	</t>		</t>
	<t>		<t>
	This callback is meant to be used by servers to help reduce the latency of		This callback is meant to be used by servers to help reduce the latency of
	blocking locks in the case where they recognize that a client that has		blocking locks in the case where they recognize that a client that has
	been polling for a blocking byte-range lock may now be able to acquire the lock.		been polling for a blocking byte-range lock may now be able to acquire the lock.
	If the server supports this callback for a given file, it MUST set the		If the server supports this callback for a given file, it <bcp14>MUST</bcp 14> set the
	OPEN4_RESULT_MAY_NOTIFY_LOCK flag when responding to successful opens		OPEN4_RESULT_MAY_NOTIFY_LOCK flag when responding to successful opens
	for that file. This does not commit the server to the use of CB_NOTIFY_LO CK,		for that file. This does not commit the server to the use of CB_NOTIFY_LO CK,
	but the client may use this as a hint to decide how frequently to poll		but the client may use this as a hint to decide how frequently to poll
	for locks derived from that open.		for locks derived from that open.
	</t>		</t>
	<t>		<t>
	If an OPEN operation results in an upgrade, in which the stateid returned		If an OPEN operation results in an upgrade, in which the stateid returned
	has an "other" value matching that of a stateid already allocated, with a		has an "other" value matching that of a stateid already allocated, with a
	new "seqid" indicating a change in the lock being represented, then the		new "seqid" indicating a change in the lock being represented, then the
	value of the OPEN4_RESULT_MAY_NOTIFY_LOCK flag when responding to that new		value of the OPEN4_RESULT_MAY_NOTIFY_LOCK flag when responding to that new
	OPEN controls handling from that point going forward. When parallel OPENs		OPEN controls handling from that point going forward. When parallel OPENs
	are done on the same file and open-owner, the ordering of the "seqid" fiel ds		are done on the same file and open-owner, the ordering of the "seqid" fiel ds
	of the returned stateids (subject to wraparound) are to be used to select		of the returned stateids (subject to wraparound) are to be used to select
	the controlling value of the OPEN4_RESULT_MAY_NOTIFY_LOCK flag.		the controlling value of the OPEN4_RESULT_MAY_NOTIFY_LOCK flag.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_CB_NOTIFY_LOCK_IMPLEMENTATION" title="IMPLEM		<section toc="exclude" anchor="OP_CB_NOTIFY_LOCK_IMPLEMENTATION" numbere
	ENTATION">		d="true">
	<t>		<name>IMPLEMENTATION</name>
	The server MUST NOT grant the byte-range lock to the client unless and unti		<t>
	l it		The server <bcp14>MUST NOT</bcp14> grant the byte-range lock to the client
			unless and until it
	receives a LOCK operation from the client. Similarly, the client		receives a LOCK operation from the client. Similarly, the client
	receiving this callback cannot assume that it now has the lock or that a		receiving this callback cannot assume that it now has the lock or that a
	subsequent LOCK operation for the lock will be successful.		subsequent LOCK operation for the lock will be successful.
	</t>		</t>
	<t>		<t>
	The server is not required to implement this callback, and even if it		The server is not required to implement this callback, and even if it
	does, it is not required to use it in any particular case. Therefore, the		does, it is not required to use it in any particular case. Therefore, the
	client must still rely on polling for blocking locks, as described in		client must still rely on polling for blocking locks, as described in
	<xref target="blocking_locks"/>.		<xref target="blocking_locks" format="default"/>.
	</t>		</t>
	<t>		<t>
	Similarly, the client is not required to implement this callback, and even		Similarly, the client is not required to implement this callback, and even
	it does, is still free to ignore it. Therefore, the server MUST NOT assume		it does, is still free to ignore it. Therefore, the server <bcp14>MUST NOT </bcp14> assume
	that the client will act based on the callback.		that the client will act based on the callback.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="OP_CB_NOTIFY_DEVICEID" numbered="true" toc="default">
	$ -->		<name>Operation 14: CB_NOTIFY_DEVICEID - Notify Client of Device ID Chan
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		ges</name>
	<!-- Copyright (C) The Internet Society (2006) -->		<section toc="exclude" anchor="OP_CB_NOTIFY_DEVICEID_ARGUMENT" numbered=
	<section anchor="OP_CB_NOTIFY_DEVICEID" title="Operation 14: CB_NOTIFY_DEVICEID		"true">
	- Notify Client of Device ID Changes" >		<name>ARGUMENT</name>
			<sourcecode type="xdr"><![CDATA[
	<section toc="exclude" anchor="OP_CB_NOTIFY_DEVICEID_ARGUMENT" title="ARGUMENT
	">
	<figure>
	<artwork>
	/*		/*
	* Device notification types.		* Device notification types.
	*/		*/
	enum notify_deviceid_type4 {		enum notify_deviceid_type4 {
	NOTIFY_DEVICEID4_CHANGE = 1,		NOTIFY_DEVICEID4_CHANGE = 1,
	NOTIFY_DEVICEID4_DELETE = 2		NOTIFY_DEVICEID4_DELETE = 2
	};		};
	/* For NOTIFY4_DEVICEID4_DELETE */		/* For NOTIFY4_DEVICEID4_DELETE */
	struct notify_deviceid_delete4 {		struct notify_deviceid_delete4 {
	skipping to change at line 41715 ¶		skipping to change at line 41531 ¶
	};		};
	/* For NOTIFY4_DEVICEID4_CHANGE */		/* For NOTIFY4_DEVICEID4_CHANGE */
	struct notify_deviceid_change4 {		struct notify_deviceid_change4 {
	layouttype4 ndc_layouttype;		layouttype4 ndc_layouttype;
	deviceid4 ndc_deviceid;		deviceid4 ndc_deviceid;
	bool ndc_immediate;		bool ndc_immediate;
	};		};
	struct CB_NOTIFY_DEVICEID4args {		struct CB_NOTIFY_DEVICEID4args {
	notify4 cnda_changes&lt;>;		notify4 cnda_changes<>;
	};		};
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_CB_NOTIFY_DEVICEID_RESULT" numbered="t
	</section>		rue">
	<section toc="exclude" anchor="OP_CB_NOTIFY_DEVICEID_RESULT" title="RESULT">		<name>RESULT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	struct CB_NOTIFY_DEVICEID4res {		struct CB_NOTIFY_DEVICEID4res {
	nfsstat4 cndr_status;		nfsstat4 cndr_status;
	};		};
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_CB_NOTIFY_DEVICEID_DESCRIPTION" number
	</section>		ed="true">
	<section toc="exclude" anchor="OP_CB_NOTIFY_DEVICEID_DESCRIPTION" title="DESCR		<name>DESCRIPTION</name>
	IPTION">		<t>
	<t>
	The CB_NOTIFY_DEVICEID operation is used by the		The CB_NOTIFY_DEVICEID operation is used by the
	server to send notifications to clients about		server to send notifications to clients about
	changes to pNFS device IDs. The registration of		changes to pNFS device IDs. The registration of
	device ID notifications is optional and is done via		device ID notifications is optional and is done via
	GETDEVICEINFO. These notifications are sent		GETDEVICEINFO. These notifications are sent
	over the backchannel		over the backchannel
	once the original request has been processed		once the original request has been processed
	on the server. The server will send an array of		on the server. The server will send an array of
	notifications, cnda_changes, as a list of pairs of		notifications, cnda_changes, as a list of pairs of
	bitmaps and values. See <xref target="fattr4" />		bitmaps and values. See <xref target="fattr4" format="default"/>
	for a description of how NFSv4.1 bitmaps work.		for a description of how NFSv4.1 bitmaps work.
	</t>		</t>
			<t>
	<t>		As with CB_NOTIFY (<xref target="OP_CB_NOTIFY_DESCRIPTION" format="default"/
	As with CB_NOTIFY (<xref		>), it is
	target="OP_CB_NOTIFY_DESCRIPTION"/>), it is
	possible the server has more notifications than		possible the server has more notifications than
	can fit in a CB_COMPOUND, thus requiring multiple		can fit in a CB_COMPOUND, thus requiring multiple
	CB_COMPOUNDs. Unlike CB_NOTIFY, serialization is not		CB_COMPOUNDs. Unlike CB_NOTIFY, serialization is not
	an issue because unlike directory entries, device		an issue because unlike directory entries, device
	IDs cannot be re-used after being deleted (<xref		IDs cannot be re-used after being deleted (<xref target="device_ids" format=
	target="device_ids" />).		"default"/>).
	</t>
	<t>		</t>
			<t>
	All device ID notifications contain a device ID and a		All device ID notifications contain a device ID and a
	layout type. The layout type is necessary because two		layout type. The layout type is necessary because two
	different layout types can share the same device ID,		different layout types can share the same device ID,
	and the common device ID can have completely different		and the common device ID can have completely different
	mappings for each layout type.		mappings for each layout type.
	</t>		</t>
			<t>
	<t>
	The server will send the following notifications:		The server will send the following notifications:
	<list style="hanging">		</t>
			<dl newline="true" spacing="normal">
	<t hangText="NOTIFY_DEVICEID4_CHANGE"><vspace />		<dt>NOTIFY_DEVICEID4_CHANGE</dt>
			<dd>
	A previously provided device-ID-to-device-address		A previously provided device-ID-to-device-address
	mapping has changed and the client uses		mapping has changed and the client uses
	GETDEVICEINFO to obtain the		GETDEVICEINFO to obtain the
	updated mapping.		updated mapping.
	The notification is encoded in a value of data		The notification is encoded in a value of data
	type notify_deviceid_change4. This data type		type notify_deviceid_change4. This data type
	also contains a boolean field, ndc_immediate,		also contains a boolean field, ndc_immediate,
	which if TRUE indicates that the change will be		which if TRUE indicates that the change will be
	enforced immediately, and so the client might not		enforced immediately, and so the client might not
	be able to complete any pending I/O to the device		be able to complete any pending I/O to the device
	ID. If ndc_immediate is FALSE, then for an		ID. If ndc_immediate is FALSE, then for an
	indefinite time, the client can complete pending		indefinite time, the client can complete pending
	I/O. After pending I/O is complete, the client		I/O. After pending I/O is complete, the client
	SHOULD get the new device-ID-to-device-address		<bcp14>SHOULD</bcp14> get the new device-ID-to-device-address
	mappings before sending new I/O requests to the		mappings before sending new I/O requests to the
	storage devices addressed by the device ID.		storage devices addressed by the device ID.
	</t>		</dd>
			<dt>NOTIFY4_DEVICEID_DELETE</dt>
	<t hangText="NOTIFY4_DEVICEID_DELETE"><vspace />		<dd>
			<t>
	Deletes a device ID from the mappings. This		Deletes a device ID from the mappings. This
	notification MUST NOT be sent if the client has		notification <bcp14>MUST NOT</bcp14> be sent if the client has
	a layout that refers to the device ID. In other		a layout that refers to the device ID. In other
	words, if the server is sending a delete device ID		words, if the server is sending a delete device ID
	notification, one of the following is true for layouts		notification, one of the following is true for layouts
	associated with the layout type:		associated with the layout type:
	<list style="symbols">		</t>
			<ul spacing="normal">
	<t>		<li>
	The client never had a layout referring to that device ID.		The client never had a layout referring to that device ID.
	</t>		</li>
			<li>
	<t>
	The client has returned all layouts referring to that device ID.		The client has returned all layouts referring to that device ID.
	</t>		</li>
			<li>
	<t>
	The server has revoked all layouts referring to that device ID.		The server has revoked all layouts referring to that device ID.
	</t>		</li>
			</ul>
	</list>		<t>
	The notification is encoded in a value of data		The notification is encoded in a value of data
	type notify_deviceid_delete4.		type notify_deviceid_delete4.
	After a server deletes a device ID, it MUST NOT		After a server deletes a device ID, it <bcp14>MUST NOT</bcp14>
	reuse that device ID for the same layout type until the		reuse that device ID for the same layout type until the
	client ID is deleted.		client ID is deleted.
	</t>		</t>
	</list>		</dd>
	</t>		</dl>
	</section>		</section>
			</section>
	</section>		<section anchor="OP_CB_ILLEGAL" numbered="true" toc="default">
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<name>Operation 10044: CB_ILLEGAL - Illegal Callback Operation</name>
	$ -->		<section toc="exclude" anchor="OP_CB_ILLEGAL_ARGUMENT" numbered="true">
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<name>ARGUMENT</name>
	<!-- Copyright (C) The Internet Society (2006) -->		<sourcecode type="xdr"><![CDATA[
	<section anchor="OP_CB_ILLEGAL" title="Operation 10044: CB_ILLEGAL - Illegal Cal
	lback Operation" >
	<section toc="exclude" anchor="OP_CB_ILLEGAL_ARGUMENT" title="ARGUMENT">
	<figure>
	<artwork>
	void;		void;
	</artwork>		]]></sourcecode>
	</figure>		</section>
	</section>		<section toc="exclude" anchor="OP_CB_ILLEGAL_RESULT" numbered="true">
	<section toc="exclude" anchor="OP_CB_ILLEGAL_RESULT" title="RESULT">		<name>RESULT</name>
	<figure>		<sourcecode type="xdr"><![CDATA[
	<artwork>
	/*		/*
	* CB_ILLEGAL: Response for illegal operation numbers		* CB_ILLEGAL: Response for illegal operation numbers
	*/		*/
	struct CB_ILLEGAL4res {		struct CB_ILLEGAL4res {
	nfsstat4 status;		nfsstat4 status;
	};		};
			]]></sourcecode>
	</artwork>		</section>
	</figure>		<section toc="exclude" anchor="OP_CB_ILLEGAL_DESCRIPTION" numbered="true
	</section>		">
	<section toc="exclude" anchor="OP_CB_ILLEGAL_DESCRIPTION" title="DESCRIPTION">		<name>DESCRIPTION</name>
	<t>		<t>
	This operation is a placeholder for encoding a		This operation is a placeholder for encoding a
	result to handle the case of the server sending		result to handle the case of the server sending
	an operation code within CB_COMPOUND that is not		an operation code within CB_COMPOUND that is not
	defined in the NFSv4.1 specification. See <xref		defined in the NFSv4.1 specification. See <xref target="OP_CB_COMPOUND_DESC
	target="OP_CB_COMPOUND_DESCRIPTION"/> for more details.		RIPTION" format="default"/> for more details.
	</t>		</t>
	<t>		<t>
	The status field of CB_ILLEGAL4res MUST be set to		The status field of CB_ILLEGAL4res <bcp14>MUST</bcp14> be set to
	NFS4ERR_OP_ILLEGAL.		NFS4ERR_OP_ILLEGAL.
	</t>		</t>
	</section>		</section>
	<section toc="exclude" anchor="OP_CB_ILLEGAL_IMPLEMENTATION" title="IMPLEMENTA		<section toc="exclude" anchor="OP_CB_ILLEGAL_IMPLEMENTATION" numbered="t
	TION">		rue">
	<t>		<name>IMPLEMENTATION</name>
			<t>
	A server will probably not send an operation with code		A server will probably not send an operation with code
	OP_CB_ILLEGAL, but if it does, the response will be CB_ILLEGAL4res		OP_CB_ILLEGAL, but if it does, the response will be CB_ILLEGAL4res
	just as it would be with any other invalid operation code. Note		just as it would be with any other invalid operation code. Note
	that if the client gets an illegal operation code that is not		that if the client gets an illegal operation code that is not
	OP_ILLEGAL, and if the client checks for legal operation codes		OP_ILLEGAL, and if the client checks for legal operation codes
	during the XDR decode phase, then an instance of		during the XDR decode phase, then an instance of
	data type CB_ILLEGAL4res will not be returned.		data type CB_ILLEGAL4res will not be returned.
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->
	<!-- Copyright (C) The IETF Trust (2007) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<section anchor="SECCON" numbered="true" toc="default">
	$ -->		<name>Security Considerations</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<t>
	<!-- Copyright (C) The Internet Society (2006) -->
	<section anchor="SECCON" title="Security Considerations">
	<t>
	Historically, the authentication model of NFS		Historically, the authentication model of NFS
	was based on the entire machine being the NFS client, with the		was based on the entire machine being the NFS client, with the
	NFS server trusting the NFS client		NFS server trusting the NFS client
	to authenticate the end-user.		to authenticate the end-user.
	The NFS server in turn shared its files only to		The NFS server in turn shared its files only to
	specific clients, as identified by the client's source		specific clients, as identified by the client's source
	network address. Given this model, the AUTH_SYS		network address. Given this model, the AUTH_SYS
	RPC security flavor simply identified the end-user		RPC security flavor simply identified the end-user
	using the client to the NFS server. When processing		using the client to the NFS server. When processing
	NFS responses, the client ensured that the responses		NFS responses, the client ensured that the responses
	came from the same network address and port number		came from the same network address and port number
	to which the request was sent. While such a model is		to which the request was sent. While such a model is
	easy to implement and simple to deploy and use, it is		easy to implement and simple to deploy and use, it is
	unsafe. Thus, NFSv4.1		unsafe. Thus, NFSv4.1
	implementations are REQUIRED to support a security model that uses		implementations are <bcp14>REQUIRED</bcp14> to support a security model that uses
	end-to-end authentication, where an end-user on a client		end-to-end authentication, where an end-user on a client
	mutually authenticates (via cryptographic schemes that		mutually authenticates (via cryptographic schemes that
	do not expose passwords or keys in the clear on the		do not expose passwords or keys in the clear on the
	network) to a principal on an NFS server. Consideration		network) to a principal on an NFS server. Consideration
	is also given to the integrity and privacy of		is also given to the integrity and privacy of
	NFS requests and responses. The issues of end-to-end		NFS requests and responses. The issues of end-to-end
	mutual authentication, integrity, and privacy are		mutual authentication, integrity, and privacy are
	discussed in <xref target="RPCSEC_GSS_and_Security_Services" />.		discussed in <xref target="RPCSEC_GSS_and_Security_Services" format="default" />.
	There are specific considerations when using Kerberos V5 as described		There are specific considerations when using Kerberos V5 as described
	in <xref target="krb5_sec_consider"/>.		in <xref target="krb5_sec_consider" format="default"/>.
	</t>		</t>
	<t>		<t>
	Note that being REQUIRED to implement does not mean REQUIRED to		Note that being <bcp14>REQUIRED</bcp14> to implement does not mean <bcp14>REQ
			UIRED</bcp14> to
	use; AUTH_SYS can be used by NFSv4.1 clients and servers.		use; AUTH_SYS can be used by NFSv4.1 clients and servers.
	However, AUTH_SYS is merely an OPTIONAL security flavor in NFSv4.1,		However, AUTH_SYS is merely an <bcp14>OPTIONAL</bcp14> security flavor in NFS v4.1,
	and so interoperability via AUTH_SYS is not assured.		and so interoperability via AUTH_SYS is not assured.
	</t>		</t>
	<t>		<t>
	For reasons of reduced administration overhead, better		For reasons of reduced administration overhead, better
	performance, and/or reduction of CPU utilization,		performance, and/or reduction of CPU utilization,
	users of NFSv4.1 implementations might decline to use		users of NFSv4.1 implementations might decline to use
	security mechanisms that enable integrity protection		security mechanisms that enable integrity protection
	on each remote procedure call and response. The		on each remote procedure call and response. The
	use of mechanisms without integrity leaves the user		use of mechanisms without integrity leaves the user
	vulnerable to a man-in-the-middle of the NFS		vulnerable to a man-in-the-middle of the NFS
	client and server that modifies the RPC request and/or		client and server that modifies the RPC request and/or
	the response. While implementations are free to provide		the response. While implementations are free to provide
	the option to use weaker security mechanisms, there		the option to use weaker security mechanisms, there
	are three operations in particular that warrant the		are three operations in particular that warrant the
	implementation overriding user choices.		implementation overriding user choices.
	<list style='symbols'>		</t>
			<ul spacing="normal">
	<t>		<li>
	The first two such operations are SECINFO and		The first two such operations are SECINFO and
	SECINFO_NO_NAME. It is RECOMMENDED that the client send		SECINFO_NO_NAME. It is <bcp14>RECOMMENDED</bcp14> that the client send
	both operations such that they are protected with a		both operations such that they are protected with a
	security flavor that has integrity protection, such		security flavor that has integrity protection, such
	as RPCSEC_GSS with either the rpc_gss_svc_integrity		as RPCSEC_GSS with either the rpc_gss_svc_integrity
	or rpc_gss_svc_privacy service. Without integrity		or rpc_gss_svc_privacy service. Without integrity
	protection encapsulating SECINFO and SECINFO_NO_NAME		protection encapsulating SECINFO and SECINFO_NO_NAME
	and their results, a man-in-the-middle could		and their results, a man-in-the-middle could
	modify results such that the client might select a		modify results such that the client might select a
	weaker algorithm in the set allowed by the server, making		weaker algorithm in the set allowed by the server, making
	the client and/or server vulnerable to further attacks.		the client and/or server vulnerable to further attacks.
	</t>		</li>
	<t>		<li>
	The third operation that SHOULD use integrity protection		The third operation that <bcp14>SHOULD</bcp14> use integrity protection
	is any GETATTR for the fs_locations and fs_locations_info attributes,		is any GETATTR for the fs_locations and fs_locations_info attributes,
	in order to mitigate the severity of a man-in-the-middle attack.		in order to mitigate the severity of a man-in-the-middle attack.
	The attack has two		The attack has two
	steps. First the attacker modifies the unprotected results of some		steps. First the attacker modifies the unprotected results of some
	operation to return NFS4ERR_MOVED. Second, when the client follows up		operation to return NFS4ERR_MOVED. Second, when the client follows up
	with a GETATTR for the fs_locations or fs_locations_info attributes,		with a GETATTR for the fs_locations or fs_locations_info attributes,
	the attacker modifies		the attacker modifies
	the results to cause the client to migrate its traffic to a server		the results to cause the client to migrate its traffic to a server
	controlled by the attacker. With integrity protection, this attack is mitigat ed.		controlled by the attacker. With integrity protection, this attack is mitigat ed.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Relative to previous NFS versions, NFSv4.1 has additional security		Relative to previous NFS versions, NFSv4.1 has additional security
	considerations for pNFS (see Sections <xref target="security_considerations_pn		considerations for pNFS (see Sections <xref target="security_considerations_pn
	fs" format="counter" />		fs" format="counter"/>
	and <xref target="file_security_considerations" format="counter" />), locking		and <xref target="file_security_considerations" format="counter"/>), locking
	and session state (see <xref target="protect_state_change"/>),		and session state (see <xref target="protect_state_change" format="default"/>)
	and state recovery during grace period (see <xref		,
	target="reclaim_security_considerations"/>).		and state recovery during grace period (see <xref target="reclaim_security_con
			siderations" format="default"/>).
	With respect to locking and session state, if SP4_SSV state protection		With respect to locking and session state, if SP4_SSV state protection
	is being used, <xref target="rpcsec_ssv_consider"/> has specific		is being used, <xref target="rpcsec_ssv_consider" format="default"/> has speci fic
	security considerations for the NFSv4.1 client and server.		security considerations for the NFSv4.1 client and server.
	</t>		</t>
	<t>		<t>
	Security considerations for lock reclaim differ between the two different		Security considerations for lock reclaim differ between the two different
	situations in which state reclaim is to be done.		situations in which state reclaim is to be done.
	The server failure situation is discussed in		The server failure situation is discussed in
	<xref target="reclaim_security_considerations"/> while the per-fs state		<xref target="reclaim_security_considerations" format="default"/>, while the p er-fs state
	reclaim done in support of migration/replication is discussed in		reclaim done in support of migration/replication is discussed in
	<xref target="SEC11-EFF-lock-sc"/>.		<xref target="SEC11-EFF-lock-sc" format="default"/>.
	</t>		</t>
	<t>		<t>
	The use of the multi-server namespace features described in		The use of the multi-server namespace features described in
	<xref target="NEW11"/> raises		<xref target="NEW11" format="default"/> raises
	the possibility that requests to determine the set of network		the possibility that requests to determine the set of network
	addresses corresponding to a given server might be interfered		addresses corresponding to a given server might be interfered
	with or have their responses modified in flight.		with or have their responses modified in flight.
	In light of this possibility, the following considerations		In light of this possibility, the following considerations
	should be taken note of:		should be noted:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	When DNS is used to convert server names to addresses and		When DNS is used to convert server names to addresses and
	DNSSEC <xref target="RFC4033"/> is not available, the validity of		DNSSEC <xref target="RFC4033" format="default"/> is not available, the val idity of
	the network addresses returned generally cannot be relied upon.		the network addresses returned generally cannot be relied upon.
	However, when combined with a trusted resolver, DNS over TLS		However, when combined with a trusted resolver, DNS over TLS
	<xref target="RFC7858"/>, and DNS over HTTPS		<xref target="RFC7858" format="default"/> and DNS over HTTPS
	<xref target="RFC8484"/> can also be relied upon to provide		<xref target="RFC8484" format="default"/> can be relied upon to provide
	valid address resolutions.		valid address resolutions.
	<vspace blankLines="1"/>		</t>
			<t>
	In situations in which the validity of the provided addresses		In situations in which the validity of the provided addresses
	cannot be relied upon and the client uses RPCSEC_GSS to access the		cannot be relied upon and the client uses RPCSEC_GSS to access the
	designated server, it is possible for mutual authentication to		designated server, it is possible for mutual authentication to
	discover invalid server addresses as long as the RPCSEC_GSS		discover invalid server addresses as long as the RPCSEC_GSS
	implementation used does not use insecure DNS queries to canonicalize		implementation used does not use insecure DNS queries to canonicalize
	the hostname components of the service principal names, as		the hostname components of the service principal names, as
	explained in <xref target="RFC4120"/>.		explained in <xref target="RFC4120" format="default"/>.
	</t>		</t>
	<t>		</li>
	The fetching of		<li>
	attributes containing file system location information SHOULD be		The fetching of attributes containing file system location
	performed using integrity protection.		information <bcp14>SHOULD</bcp14> be
	It is important to note here that		performed using integrity protection. It is important to note here that
	a client making a request of this sort without using		a client making a request of this sort without using
	integrity protection needs be aware of		integrity protection needs be aware of
	the negative consequences of doing so, which can lead to		the negative consequences of doing so, which can lead to
	invalid host names or network addresses being returned. These		invalid hostnames or network addresses being returned. These
	include cases in which the		include cases in which the
	client is directed to a server under the control of an		client is directed to a server under the control of an
	attacker, who might get access to data written or provide		attacker, who might get access to data written or provide
	incorrect values for data read.		incorrect values for data read. In light of
	In light of
	this, the client needs to recognize that using such returned		this, the client needs to recognize that using such returned
	location information to access an NFSv4 server		location information to access an NFSv4 server
	without use of RPCSEC_GSS (i.e.		without use of RPCSEC_GSS (i.e.,
	by using AUTH_SYS) poses dangers as it can result in the client		by using AUTH_SYS) poses dangers as it can result in the client
	interacting with such an attacker-controlled server, without		interacting with such an attacker-controlled server without
	any authentication facilities to verify the server's identity.		any authentication facilities to verify the server's identity.
	</t>		</li>
	<t>		<li>
	Despite the fact that it is a requirement that		Despite the fact that it is a requirement that implementations provide
	implementations provide
	"support" for use of RPCSEC_GSS, it cannot be assumed that		"support" for use of RPCSEC_GSS, it cannot be assumed that
	use of RPCSEC_GSS is always available between any particular		use of RPCSEC_GSS is always available between any particular
	client-server pair.		client-server pair.
	</t>		</li>
	<t>		<li>
	When a client has the network addresses of a server but not the		When a client has the network addresses of a server but not the
	associated host names, that would interfere with its ability		associated hostnames, that would interfere with its ability
	to use RPCSEC_GSS.		to use RPCSEC_GSS.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		In light of the above, a server <bcp14>SHOULD</bcp14> present file system loca
	In light of the above, a server SHOULD present file system location		tion
	entries that correspond to file systems on other servers using a		entries that correspond to file systems on other servers using a
	host name. This would allow the client to interrogate the		hostname. This would allow the client to interrogate the
	fs_locations on the destination server to obtain trunking information		fs_locations on the destination server to obtain trunking information
	(as well as replica information) using integrity protection,		(as well as replica information) using integrity protection,
	validating the name provided while assuring that the response has		validating the name provided while assuring that the response has
	not been modified in flight.		not been modified in flight.
	</t>		</t>
	<t>		<t>
	When RPCSEC_GSS is not available on a server, the client needs		When RPCSEC_GSS is not available on a server, the client needs
	to be aware of the fact that the location entries are subject to		to be aware of the fact that the location entries are subject to
	modification in flight and so cannot be relied upon.		modification in flight and so cannot be relied upon.
	In the case of a		In the case of a client being directed to another server after NFS4ERR_MOVED,
	client being directed to another server after NFS4ERR_MOVED,
	this could vitiate the		this could vitiate the
	authentication provided by the use of RPCSEC_GSS on the designated		authentication provided by the use of RPCSEC_GSS on the designated
	destination server.		destination server. Even when RPCSEC_GSS authentication is available
	Even when RPCSEC_GSS authentication is available
	on the destination, the server might still properly authenticate as the		on the destination, the server might still properly authenticate as the
	server to which the client was erroneously directed.		server to which the client was erroneously directed.
	Without a way to decide whether		Without a way to decide whether
	the server is a valid one, the client can only determine, using		the server is a valid one, the client can only determine, using
	RPCSEC_GSS, that the server corresponds to the name provided, with		RPCSEC_GSS, that the server corresponds to the name provided, with
	no basis for trusting that server. As a result, the client SHOULD		no basis for trusting that server. As a result, the client <bcp14>SHOULD
	NOT use such unverified location entries as a basis for migration,		NOT</bcp14> use such unverified location entries as a basis for migration,
	even though RPCSEC_GSS might be available on the destination.		even though RPCSEC_GSS might be available on the destination.
	</t>		</t>
	<t>		<t>
	When a file system location attribute is fetched		When a file system location attribute is fetched upon connecting with an
	upon connecting with an		NFS server, it <bcp14>SHOULD</bcp14>, as stated above, be done with integrity
	NFS server, it SHOULD, as stated above, be done with integrity protection.		protection.
	When this not possible, it is generally		When this not possible, it is generally
	best for the client to ignore trunking and replica information or		best for the client to ignore trunking and replica information or
	simply not fetch the location information for these purposes.		simply not fetch the location information for these purposes.
	</t>		</t>
	<t>		<t>
	When location information cannot be verified, it can be subjected		When location information cannot be verified, it can be subjected
	to additional filtering to prevent the client from being		to additional filtering to prevent the client from being
	inappropriately directed. For example, if a range of network		inappropriately directed. For example, if a range of network
	addresses can be determined that assure that the servers and		addresses can be determined that assure that the servers and
	clients using AUTH_SYS are subject to the appropriate set of		clients using AUTH_SYS are subject to the appropriate set of
	constraints (e.g. physical network isolation, administrative		constraints (e.g., physical network isolation, administrative
	controls on the operating systems used), then network addresses		controls on the operating systems used), then network addresses
	in the appropriate range can be used with others discarded		in the appropriate range can be used with others discarded
	or restricted in their use of AUTH_SYS.		or restricted in their use of AUTH_SYS.
	</t>		</t>
	<t>		<t>
	To summarize considerations regarding the use of RPCSEC_GSS in		To summarize considerations regarding the use of RPCSEC_GSS in
	fetching location information, we need to consider the following		fetching location information, we need to consider the following
	possibilities for requests to interrogate location information, with		possibilities for requests to interrogate location information, with
	interrogation approaches on the referring and destination servers		interrogation approaches on the referring and destination servers
	arrived at separately:		arrived at separately:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	The use of integrity protection is RECOMMENDED		<li>
			The use of integrity protection is <bcp14>RECOMMENDED</bcp14>
	in all cases, since the absence of integrity protection exposes		in all cases, since the absence of integrity protection exposes
	the client to the possibility of the results		the client to the possibility of the results being modified in transit.
	being modified in transit.		</li>
	</t>		<li>
	<t>
	The use of requests issued without RPCSEC_GSS		The use of requests issued without RPCSEC_GSS
	(i.e. using AUTH_SYS which has no provision to avoid		(i.e., using AUTH_SYS, which has no provision to avoid
	modification of data in flight),		modification of data in flight),
	while undesirable and a potential security exposure,		while undesirable and a potential security exposure,
	may not be avoidable in all cases.		may not be avoidable in all cases. Where the use
	Where the use
	of the returned information cannot be avoided, it is made		of the returned information cannot be avoided, it is made
	subject to filtering as described above to		subject to filtering as described above to
	eliminate the possibility that the		eliminate the possibility that the client would
	client would
	treat an invalid address as if it were a NFSv4 server. The		treat an invalid address as if it were a NFSv4 server. The
	specifics will vary depending on the degree of network isolation		specifics will vary depending on the degree of network isolation
	and whether the request is to the referring or destination servers.		and whether the request is to the referring or destination servers.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	Even if such requests are not interfered with in flight, it is possible		Even if such requests are not interfered with in flight, it is possible
	for a compromised server to direct the client to use inappropriate servers,		for a compromised server to direct the client to use inappropriate servers,
	such as those under the control of the attacker. It is not clear that being		such as those under the control of the attacker. It is not clear that being
	directed to such servers represents a greater threat to the client than the		directed to such servers represents a greater threat to the client than the
	damage that could be done by the compromised server itself. However, it		damage that could be done by the compromised server itself. However, it
	is possible that some sorts of transient server compromises might be taken		is possible that some sorts of transient server compromises might be
	advantage of to direct a client to a server capable of doing greater		exploited to direct a client to a server capable of doing greater
	damage over a longer time. One useful step to guard against this		damage over a longer time. One useful step to guard against this
	possibility is to issue requests to fetch location data using RPCSEC_GSS,		possibility is to issue requests to fetch location data using RPCSEC_GSS,
	even if no mapping to an RPCSEC_GSS principal is available. In this case,		even if no mapping to an RPCSEC_GSS principal is available. In this case,
	RPCSEC_GSS would not be used, as it typically is, to identify the client		RPCSEC_GSS would not be used, as it typically is, to identify the client
	principal to the server, but rather to make sure (via RPCSEC_GSS mutual		principal to the server, but rather to make sure (via RPCSEC_GSS mutual
	authentication) that the server being contacted is the one intended.		authentication) that the server being contacted is the one intended.
	</t>		</t>
	<t>		<t>
	Similar considerations apply if the threat to be avoided is the redirection		Similar considerations apply if the threat to be avoided is the redirection
	of client traffic to inappropriate (i.e. poorly performing) servers. In		of client traffic to inappropriate (i.e., poorly performing) servers. In
	both cases, there is no reason for the information returned to depend on		both cases, there is no reason for the information returned to depend on
	the identity of the client principal requesting it, while the validity of the		the identity of the client principal requesting it, while the validity of the
	server information, which has the capability to affect all client principals,		server information, which has the capability to affect all client principals,
	is of considerable importance.		is of considerable importance.
	</t>		</t>
	</section>		</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->		<section anchor="ianaconsider" numbered="true" toc="default">
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<name>IANA Considerations</name>
	<!-- Copyright (C) The Internet Society (2006) -->		<t>
	<section anchor="ianaconsider"		This section uses terms that are defined in <xref target="RFC8126" format="def
	title="IANA Considerations">		ault"/>.
	<t>
	This section uses terms that are defined in <xref target="RFC5226"/>.
	</t>		</t>
	<section anchor="Iana-actions"		<section anchor="Iana-actions" numbered="true" toc="default">
	title="IANA Actions Needed">		<name>IANA Actions</name>
	<t>		<t>
	This update does not require any modification of or additions to registry		This update does not require any modification of, or additions to, registr
			y
	entries or registry rules associated with NFSv4.1. However, since		entries or registry rules associated with NFSv4.1. However, since
	this document is intended to obsolete RFC5661, it will be necessary		this document obsoletes RFC 5661, IANA has updated all registry entries an
	for IANA to update all registry entries and registry rules references		d registry rules references
	that points to RFC5661 to point to this document instead.		that point to RFC 5661 to point to this document instead.
	</t>		</t>
	<t>		<t>
	Previous actions by IANA related to NFSv4.1 are listed in the remaining		Previous actions by IANA related to NFSv4.1 are listed in the remaining
	subsections of <xref target="ianaconsider"/>.		subsections of <xref target="ianaconsider" format="default"/>.
	</t>		</t>
	</section>		</section>
	<section anchor="namedattributesiana"		<section anchor="namedattributesiana" numbered="true" toc="default">
	title="Named Attribute Definitions">		<name>Named Attribute Definitions</name>
	<t>		<t>
	IANA created a registry called the "NFSv4 Named Attribute Definitions Regis try".		IANA created a registry called the "NFSv4 Named Attribute Definitions Regis try".
	</t>		</t>
	<t>		<t>
	The NFSv4.1 protocol supports the association of a file with zero or		The NFSv4.1 protocol supports the association of a file with zero or
	more named attributes. The namespace identifiers for these attributes		more named attributes. The namespace identifiers for these attributes
	are defined as string names. The protocol does not define the		are defined as string names. The protocol does not define the
	specific assignment of the namespace for these file attributes.		specific assignment of the namespace for these file attributes.
	The IANA registry promotes interoperability where common interests exist.		The IANA registry promotes interoperability where common interests exist.
	While application developers are allowed to define and use		While application developers are allowed to define and use
	attributes as needed, they are encouraged to register the		attributes as needed, they are encouraged to register the
	attributes with IANA.		attributes with IANA.
	</t>		</t>
	<t>		<t>
	Such registered named attributes are presumed to apply to all minor		Such registered named attributes are presumed to apply to all minor
	versions of NFSv4, including those defined subsequently to the		versions of NFSv4, including those defined subsequently to the
	registration. If the named attribute is intended to be		registration. If the named attribute is intended to be
	limited to specific minor versions, this will be clearly stated in		limited to specific minor versions, this will be clearly stated in
	the registry's assignment.		the registry's assignment.
	</t>		</t>
	<t>		<t>
	All assignments to the registry are made on a First Come First Served basis ,		All assignments to the registry are made on a First Come First Served basis ,
	per Section 4.1 of <xref target="RFC5226"/>.		per <xref target="RFC8126" sectionFormat="of" section="4.4"/>.
	The policy for each assignment is Specification Required,		The policy for each assignment is Specification Required,
	per Section 4.1 of <xref target="RFC5226"/>.		per <xref target="RFC8126" sectionFormat="of" section="4.6"/>.
	</t>		</t>
	<t>		<t>
	Under the NFSv4.1 specification, the name of a named		Under the NFSv4.1 specification, the name of a named
	attribute can in theory be up to 2^32 - 1 bytes in		attribute can in theory be up to 2<sup>32</sup> - 1 bytes in
	length, but in practice NFSv4.1 clients and servers		length, but in practice NFSv4.1 clients and servers
	will be unable to handle a string that long. IANA		will be unable to handle a string that long. IANA
	should reject any assignment request with a named		should reject any assignment request with a named
	attribute that exceeds 128 UTF-8 characters. To give the		attribute that exceeds 128 UTF-8 characters. To give the
	IESG the flexibility to set up bases of assignment of		IESG the flexibility to set up bases of assignment of
	Experimental Use and Standards Action,		Experimental Use and Standards Action,
	the prefixes of "EXPE" and "STDS" are Reserved.		the prefixes of "EXPE" and "STDS" are Reserved.
	The named attribute with a zero-length name is Reserved.		The named attribute with a zero-length name is Reserved.
	</t>		</t>
	<t>		<t>
	The prefix "PRIV" is designated for Private Use. A		The prefix "PRIV" is designated for Private Use. A
	site that wants to make use of unregistered named		site that wants to make use of unregistered named
	attributes without risk of conflicting with an		attributes without risk of conflicting with an
	assignment in IANA's registry should use the prefix		assignment in IANA's registry should use the prefix
	"PRIV" in all of its named attributes.		"PRIV" in all of its named attributes.
			</t>
	</t>		<t>
	<t>
	Because some NFSv4.1 clients and servers have case-insensitive		Because some NFSv4.1 clients and servers have case-insensitive
	semantics, the fifteen additional lower case and mixed case		semantics, the fifteen additional lower case and mixed case
	permutations of each of "EXPE", "PRIV", and "STDS" are Reserved (e.g.,		permutations of each of "EXPE", "PRIV", and "STDS" are Reserved (e.g.,
	"expe", "expE", "exPe", etc. are Reserved).		"expe", "expE", "exPe", etc. are Reserved).
	Similarly, IANA must not allow two assignments that would conflict		Similarly, IANA must not allow two assignments that would conflict
	if both named attributes were converted to a common case.		if both named attributes were converted to a common case.
	</t>		</t>
			<t>
	<t>
	The registry of named attributes is a list of assignments, each		The registry of named attributes is a list of assignments, each
	containing three fields for each assignment.		containing three fields for each assignment.
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	A US-ASCII string name that is the actual name of		A US-ASCII string name that is the actual name of
	the attribute. This name must be unique. This		the attribute. This name must be unique. This
	string name can be 1 to 128 UTF-8 characters		string name can be 1 to 128 UTF-8 characters
	long.		long.
	</t>		</li>
			<li>
	<t>
	A reference to the specification of the named attribute.		A reference to the specification of the named attribute.
	The reference can consume up to 256 bytes (or more if IANA		The reference can consume up to 256 bytes (or more if IANA
	permits).		permits).
	</t>		</li>
			<li>
	<t>
	The point of contact of the registrant. The point		The point of contact of the registrant. The point
	of contact can consume up to 256 bytes (or more if IANA		of contact can consume up to 256 bytes (or more if IANA
	permits).		permits).
	</t>		</li>
	</list>		</ol>
	</t>		<section numbered="true" toc="default">
			<name>Initial Registry</name>
	<section title="Initial Registry">		<t>
	<t>
	There is no initial registry.		There is no initial registry.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="Updating Registrations">		<name>Updating Registrations</name>
	<t>		<t>
	The registrant is always permitted to update the point of contact		The registrant is always permitted to update the point of contact
	field. Any other change will require Expert Review or IESG		field. Any other change will require Expert Review or IESG
	Approval.		Approval.
	</t>		</t>
	</section>		</section>
			</section>
	</section>		<section anchor="notifyiana" numbered="true" toc="default">
			<name>Device ID Notifications</name>
	<section anchor="notifyiana" title="Device ID Notifications">		<t>
	<t>
	IANA created a registry called the "NFSv4 Device ID		IANA created a registry called the "NFSv4 Device ID
	Notifications Registry".		Notifications Registry".
	</t>		</t>
			<t>
	<t>
	The potential exists for new notification types to be		The potential exists for new notification types to be
	added to the CB_NOTIFY_DEVICEID operation (see <xref		added to the CB_NOTIFY_DEVICEID operation (see <xref target="OP_CB_NOTIFY_
	target="OP_CB_NOTIFY_DEVICEID" />). This can be done		DEVICEID" format="default"/>). This can be done
	via changes to the operations that register		via changes to the operations that register
	notifications, or by adding new operations to NFSv4.		notifications, or by adding new operations to NFSv4.
	This requires a new minor version of NFSv4, and		This requires a new minor version of NFSv4, and
	requires a Standards Track document from the IETF.		requires a Standards Track document from the IETF.
	Another way to add a notification is to specify a new		Another way to add a notification is to specify a new
	layout type (see <xref target="pnfsiana" />).		layout type (see <xref target="pnfsiana" format="default"/>).
	</t>		</t>
	<t>		<t>
	Hence, all assignments to the registry are made on a Standards Action		Hence, all assignments to the registry are made on a Standards Action
	basis per Section 4.1 of <xref target="RFC5226"/>, with		basis per <xref target="RFC8126" section="4.6" sectionFormat="of" format="d efault"/>, with
	Expert Review required.		Expert Review required.
	</t>		</t>
	<t>		<t>
	The registry is a list of assignments, each containing		The registry is a list of assignments, each containing
	five fields per assignment.		five fields per assignment.
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	The name of the notification type. This name must have the		The name of the notification type. This name must have the
	prefix "NOTIFY_DEVICEID4_". This name must be unique.		prefix "NOTIFY_DEVICEID4_". This name must be unique.
	</t>		</li>
	<t>		<li>
	The value of the notification. IANA will assign		The value of the notification. IANA will assign
	this number, and the request from the registrant		this number, and the request from the registrant
	will use TBD1 instead of an actual value. IANA		will use TBD1 instead of an actual value. IANA
	MUST use a whole number that can be no higher		<bcp14>MUST</bcp14> use a whole number that can be no higher
	than 2^32-1, and should be the next available		than 2<sup>32</sup>-1, and should be the next available
	value. The value assigned must be unique.		value. The value assigned must be unique.
	A Designated Expert must be used to		A Designated Expert must be used to
	ensure that when the name of the notification		ensure that when the name of the notification
	type and its value are added to the NFSv4.1		type and its value are added to the NFSv4.1
	notify_deviceid_type4 enumerated data type in the		notify_deviceid_type4 enumerated data type in the
	NFSv4.1 XDR description (<xref		NFSv4.1 XDR description <xref target="RFC5662" format="default"/>, the
	target="RFC5662"/>), the result continues to		result continues to
	be a valid XDR description.		be a valid XDR description.
			</li>
	</t>		<li>
	<t>
	The Standards Track RFC(s) that describe the		The Standards Track RFC(s) that describe the
	notification. If the RFC(s) have not yet been		notification. If the RFC(s) have not yet been
	published, the registrant will use RFCTBD2, RFCTBD3, etc. instead		published, the registrant will use RFCTBD2, RFCTBD3, etc. instead
	of an actual RFC number.		of an actual RFC number.
			</li>
	</t>		<li>
	<t>
	How the RFC introduces the notification. This is		How the RFC introduces the notification. This is
	indicated by a single US-ASCII value. If the		indicated by a single US-ASCII value. If the
	value is N, it means a minor revision to the		value is N, it means a minor revision to the
	NFSv4 protocol. If the value is L, it means a new		NFSv4 protocol. If the value is L, it means a new
	pNFS layout type. Other values can be used with		pNFS layout type. Other values can be used with
	IESG Approval.		IESG Approval.
			</li>
	</t>		<li>
	<t>
	The minor versions of NFSv4 that are allowed to		The minor versions of NFSv4 that are allowed to
	use the notification. While these are numeric		use the notification. While these are numeric
	values, IANA will not allocate and assign them;		values, IANA will not allocate and assign them;
	the author of the relevant RFCs with IESG		the author of the relevant RFCs with IESG
	Approval assigns these numbers. Each time there is a		Approval assigns these numbers. Each time there is a
	new minor version of NFSv4 approved, a Designated		new minor version of NFSv4 approved, a Designated
	Expert should review the registry to make recommended		Expert should review the registry to make recommended
	updates as needed.		updates as needed.
			</li>
	</t>		</ol>
	</list>		<section numbered="true" toc="default">
	</t>		<name>Initial Registry</name>
			<t>
	<section title="Initial Registry">		The initial registry is in <xref target="devnotelist" format="default"/>. Not
	<t>		e that the
	The initial registry is in <xref target="devnotelist"/>. Note that the
	next available value is zero.		next available value is zero.
	</t>		</t>
			<table anchor="devnotelist" align="center">
	<texttable title="Initial Device ID Notification Assignments" anchor='devnotel		<name>Initial Device ID Notification Assignments</name>
	ist'>		<thead>
			<tr>
	<ttcol>Notification Name</ttcol>		<th align="left">Notification Name</th>
	<ttcol>Value</ttcol>		<th align="left">Value</th>
	<ttcol>RFC</ttcol>		<th align="left">RFC</th>
	<ttcol>How</ttcol>		<th align="left">How</th>
	<ttcol>Minor Versions</ttcol>		<th align="left">Minor Versions</th>
			</tr>
	<c>NOTIFY_DEVICEID4_CHANGE</c> <c>1</c> <c>RFC5661</c> <c>N</c> <c>1</c>		</thead>
			<tbody>
	<c>NOTIFY_DEVICEID4_DELETE</c> <c>2</c> <c>RFC5661</c> <c>N</c> <c>1</c>		<tr>
			<td align="left">NOTIFY_DEVICEID4_CHANGE</td>
	</texttable>		<td align="left">1</td>
			<td align="left">RFC 8881</td>
	</section>		<td align="left">N</td>
			<td align="left">1</td>
	<section title="Updating Registrations">		</tr>
	<t>		<tr>
			<td align="left">NOTIFY_DEVICEID4_DELETE</td>
			<td align="left">2</td>
			<td align="left">RFC 8881</td>
			<td align="left">N</td>
			<td align="left">1</td>
			</tr>
			</tbody>
			</table>
			</section>
			<section numbered="true" toc="default">
			<name>Updating Registrations</name>
			<t>
	The update of a registration will require IESG		The update of a registration will require IESG
	Approval on the advice of a Designated Expert.		Approval on the advice of a Designated Expert.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		<section anchor="recalliana" numbered="true" toc="default">
			<name>Object Recall Types</name>
	<section anchor="recalliana" title="Object Recall Types">		<t>
	<t>
	IANA created a registry called the "NFSv4 Recallable Object Types Registry" .		IANA created a registry called the "NFSv4 Recallable Object Types Registry" .
	</t>		</t>
	<t>		<t>
	The potential exists for new object types to be added to the CB_RECALL_ANY operation (see		The potential exists for new object types to be added to the CB_RECALL_ANY operation (see
	<xref target="OP_CB_RECALL_ANY" />). This can be done via changes to		<xref target="OP_CB_RECALL_ANY" format="default"/>). This can be done via changes to
	the operations that add recallable types, or by adding new operations		the operations that add recallable types, or by adding new operations
	to NFSv4. This requires a new minor version of NFSv4, and requires		to NFSv4. This requires a new minor version of NFSv4, and requires
	a Standards Track document from IETF. Another way to		a Standards Track document from IETF. Another way to
	add a new recallable object is to specify a new layout type (see <xref tar		add a new recallable object is to specify a new layout type (see <xref tar
	get="pnfsiana" />).		get="pnfsiana" format="default"/>).
	</t>		</t>
	<t>		<t>
	All assignments to the registry are made on a Standards Action		All assignments to the registry are made on a Standards Action
	basis per Section 4.1 of <xref target="RFC5226"/>, with		basis per <xref target="RFC8126" sectionFormat="of" section="4.9"/>, with
	Expert Review required.		Expert Review required.
	</t>		</t>
	<t>		<t>
	Recallable object types are 32-bit unsigned numbers. There are no Reserved		Recallable object types are 32-bit unsigned numbers. There are no Reserved
	values. Values in the range 12 through 15, inclusive, are designated for Pri vate		values. Values in the range 12 through 15, inclusive, are designated for Pri vate
	Use.		Use.
	</t>		</t>
			<t>
	<t>
	The registry is a list of assignments, each containing		The registry is a list of assignments, each containing
	five fields per assignment.		five fields per assignment.
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	The name of the recallable object type. This name must have the		The name of the recallable object type. This name must have the
	prefix "RCA4_TYPE_MASK_". The name must be unique.		prefix "RCA4_TYPE_MASK_". The name must be unique.
	</t>		</li>
	<t>		<li>
	The value of the recallable object type. IANA		The value of the recallable object type. IANA
	will assign this number, and the request from the		will assign this number, and the request from the
	registrant will use TBD1 instead of an actual		registrant will use TBD1 instead of an actual
	value. IANA MUST use a whole number that can be		value. IANA <bcp14>MUST</bcp14> use a whole number that can be
	no higher than 2^32-1, and should be the next		no higher than 2<sup>32</sup>-1, and should be the next
	available value. The value must be unique. A		available value. The value must be unique. A
	Designated Expert must be used to ensure that		Designated Expert must be used to ensure that
	when the name of the recallable type and its		when the name of the recallable type and its
	value are added to the NFSv4 XDR description		value are added to the NFSv4 XDR description
	<xref target="RFC5662"/>,		<xref target="RFC5662" format="default"/>,
	the result continues to be a valid XDR		the result continues to be a valid XDR
	description.		description.
			</li>
	</t>		<li>
	<t>
	The Standards Track RFC(s) that describe the		The Standards Track RFC(s) that describe the
	recallable object type. If the RFC(s) have not yet been		recallable object type. If the RFC(s) have not yet been
	published, the registrant will use RFCTBD2, RFCTBD3, etc. instead		published, the registrant will use RFCTBD2, RFCTBD3, etc. instead
	of an actual RFC number.		of an actual RFC number.
			</li>
	</t>		<li>
	<t>
	How the RFC introduces the recallable object type. This is		How the RFC introduces the recallable object type. This is
	indicated by a single US-ASCII value. If the		indicated by a single US-ASCII value. If the
	value is N, it means a minor revision to the		value is N, it means a minor revision to the
	NFSv4 protocol. If the value is L, it means a new		NFSv4 protocol. If the value is L, it means a new
	pNFS layout type. Other values can be used with		pNFS layout type. Other values can be used with
	IESG Approval.		IESG Approval.
			</li>
	</t>		<li>
	<t>
	The minor versions of NFSv4 that are allowed to		The minor versions of NFSv4 that are allowed to
	use the recallable object type. While these		use the recallable object type. While these
	are numeric values, IANA will not allocate and		are numeric values, IANA will not allocate and
	assign them; the author of the relevant RFCs with		assign them; the author of the relevant RFCs with
	IESG Approval assigns these numbers. Each time		IESG Approval assigns these numbers. Each time
	there is a new minor version of NFSv4 approved, a		there is a new minor version of NFSv4 approved, a
	Designated Expert should review the registry to		Designated Expert should review the registry to
	make recommended updates as needed.		make recommended updates as needed.
			</li>
	</t>		</ol>
	</list>		<section numbered="true" toc="default">
	</t>		<name>Initial Registry</name>
			<t>
	<section title="Initial Registry">		The initial registry is in <xref target="recalllist" format="default"/>. Note
	<t>		that
	The initial registry is in <xref target="recalllist"/>. Note that
	the next available value is five.		the next available value is five.
	</t>		</t>
			<table anchor="recalllist" align="center">
	<texttable title="Initial Recallable Object Type Assignments" anchor='recallli		<name>Initial Recallable Object Type Assignments</name>
	st'>		<thead>
			<tr>
	<ttcol>Recallable Object Type Name</ttcol>		<th align="left">Recallable Object Type Name</th>
	<ttcol>Value</ttcol>		<th align="left">Value</th>
	<ttcol>RFC</ttcol>		<th align="left">RFC</th>
	<ttcol>How</ttcol>		<th align="left">How</th>
	<ttcol>Minor Versions</ttcol>		<th align="left">Minor Versions</th>
			</tr>
	<c>RCA4_TYPE_MASK_RDATA_DLG</c> <c>0</c> <c>RFC 5661</c> <c>N</c> <c>1</c		</thead>
	>		<tbody>
			<tr>
	<c>RCA4_TYPE_MASK_WDATA_DLG</c> <c>1</c> <c>RFC 5661</c> <c>N</c> <c>1</c		<td align="left">RCA4_TYPE_MASK_RDATA_DLG</td>
	>		<td align="left">0</td>
			<td align="left">RFC 8881</td>
	<c>RCA4_TYPE_MASK_DIR_DLG</c> <c>2</c> <c>RFC 5661</c> <c>N</c> <c>1</c>		<td align="left">N</td>
			<td align="left">1</td>
	<c>RCA4_TYPE_MASK_FILE_LAYOUT</c> <c>3</c> <c>RFC 5661</c> <c>N</c> <c>1<		</tr>
	/c>		<tr>
			<td align="left">RCA4_TYPE_MASK_WDATA_DLG</td>
	<c>RCA4_TYPE_MASK_BLK_LAYOUT</c> <c>4</c> <c>RFC 5661</c> <c>L</c> <c>1</		<td align="left">1</td>
	c>		<td align="left">RFC 8881</td>
			<td align="left">N</td>
	<c>RCA4_TYPE_MASK_OBJ_LAYOUT_MIN</c> <c>8</c> <c>RFC 5661</c> <c>L</c> <c		<td align="left">1</td>
	>1</c>		</tr>
	<c>RCA4_TYPE_MASK_OBJ_LAYOUT_MAX</c> <c>9</c> <c>RFC 5661</c> <c>L</c> <c		<tr>
	>1</c>		<td align="left">RCA4_TYPE_MASK_DIR_DLG</td>
			<td align="left">2</td>
	</texttable>		<td align="left">RFC 8881</td>
			<td align="left">N</td>
	</section>		<td align="left">1</td>
			</tr>
	<section title="Updating Registrations">		<tr>
	<t>		<td align="left">RCA4_TYPE_MASK_FILE_LAYOUT</td>
			<td align="left">3</td>
			<td align="left">RFC 8881</td>
			<td align="left">N</td>
			<td align="left">1</td>
			</tr>
			<tr>
			<td align="left">RCA4_TYPE_MASK_BLK_LAYOUT</td>
			<td align="left">4</td>
			<td align="left">RFC 8881</td>
			<td align="left">L</td>
			<td align="left">1</td>
			</tr>
			<tr>
			<td align="left">RCA4_TYPE_MASK_OBJ_LAYOUT_MIN</td>
			<td align="left">8</td>
			<td align="left">RFC 8881</td>
			<td align="left">L</td>
			<td align="left">1</td>
			</tr>
			<tr>
			<td align="left">RCA4_TYPE_MASK_OBJ_LAYOUT_MAX</td>
			<td align="left">9</td>
			<td align="left">RFC 8881</td>
			<td align="left">L</td>
			<td align="left">1</td>
			</tr>
			</tbody>
			</table>
			</section>
			<section numbered="true" toc="default">
			<name>Updating Registrations</name>
			<t>
	The update of a registration will require IESG		The update of a registration will require IESG
	Approval on the advice of a Designated Expert.		Approval on the advice of a Designated Expert.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		<section anchor="pnfsiana" numbered="true" toc="default">
			<name>Layout Types</name>
	<section anchor="pnfsiana" title="Layout Types">		<t>
	<t>
	IANA created a registry called the "pNFS Layout Types Registry".		IANA created a registry called the "pNFS Layout Types Registry".
	</t>		</t>
	<t>		<t>
	All assignments to the registry are made on a Standards Action basis,		All assignments to the registry are made on a Standards Action basis,
	with Expert Review required.		with Expert Review required.
	</t>		</t>
	<t>		<t>
	Layout types are 32-bit numbers. The value zero is Reserved.		Layout types are 32-bit numbers. The value zero is Reserved.
	Values in the range 0x80000000 to 0xFFFFFFFF inclusive are designated for Private Use.		Values in the range 0x80000000 to 0xFFFFFFFF inclusive are designated for Private Use.
	IANA will assign numbers from the range		IANA will assign numbers from the range
	0x00000001 to 0x7FFFFFFF inclusive.		0x00000001 to 0x7FFFFFFF inclusive.
	</t>		</t>
	<t>		<t>
	The registry is a list of assignments, each		The registry is a list of assignments, each
	containing five fields.		containing five fields.
			</t>
	<list style='numbers'>		<ol spacing="normal" type="1">
	<t>		<li>
	The name of the layout type. This name must have the		The name of the layout type. This name must have the
	prefix "LAYOUT4_". The name must be unique.		prefix "LAYOUT4_". The name must be unique.
	</t>		</li>
			<li>
	<t>
	The value of the layout type. IANA will assign		The value of the layout type. IANA will assign
	this number, and the request from the registrant		this number, and the request from the registrant
	will use TBD1 instead of an actual value. The value		will use TBD1 instead of an actual value. The value
	assigned must be unique.		assigned must be unique.
	A Designated Expert must be used to ensure		A Designated Expert must be used to ensure
	that when the name of the layout type and		that when the name of the layout type and
	its value are added to the NFSv4.1 layouttype4		its value are added to the NFSv4.1 layouttype4
	enumerated data type in the NFSv4.1 XDR		enumerated data type in the NFSv4.1 XDR
	description (<xref		description <xref target="RFC5662" format="default"/>,
	target="RFC5662"/>),
	the result continues to be a valid XDR		the result continues to be a valid XDR
	description.		description.
			</li>
	</t>		<li>
	<t>
	The Standards Track RFC(s) that describe the		The Standards Track RFC(s) that describe the
	notification. If the RFC(s) have not yet been		notification. If the RFC(s) have not yet been
	published, the registrant will use RFCTBD2, RFCTBD3, etc. instead		published, the registrant will use RFCTBD2, RFCTBD3, etc. instead
	of an actual RFC number. Collectively, the RFC(s) must adhere to		of an actual RFC number. Collectively, the RFC(s) must adhere to
	the guidelines listed in <xref target="layout_guidelines"/>.		the guidelines listed in <xref target="layout_guidelines" format="defa
			ult"/>.
	</t>		</li>
			<li>
	<t>
	How the RFC introduces the layout type. This is		How the RFC introduces the layout type. This is
	indicated by a single US-ASCII value. If the		indicated by a single US-ASCII value. If the
	value is N, it means a minor revision to the		value is N, it means a minor revision to the
	NFSv4 protocol. If the value is L, it means a new		NFSv4 protocol. If the value is L, it means a new
	pNFS layout type. Other values can be used with		pNFS layout type. Other values can be used with
	IESG Approval.		IESG Approval.
			</li>
	</t>		<li>
	<t>
	The minor versions of NFSv4 that are allowed to		The minor versions of NFSv4 that are allowed to
	use the notification. While these are numeric		use the notification. While these are numeric
	values, IANA will not allocate and assign them;		values, IANA will not allocate and assign them;
	the author of the relevant RFCs with IESG		the author of the relevant RFCs with IESG
	Approval assigns these numbers. Each time there is		Approval assigns these numbers. Each time there is
	a new minor version of NFSv4 approved, a Designated		a new minor version of NFSv4 approved, a Designated
	Expert should review the registry to make recommended		Expert should review the registry to make recommended
	updates as needed.		updates as needed.
			</li>
	</t>		</ol>
			<section numbered="true" toc="default">
	</list>		<name>Initial Registry</name>
			<t>
	</t>		The initial registry is in <xref target="layoutlist" format="default"/>.
			</t>
	<section title="Initial Registry">		<table anchor="layoutlist" align="center">
	<t>		<name>Initial Layout Type Assignments</name>
	The initial registry is in <xref target="layoutlist"/>.		<thead>
	</t>		<tr>
			<th align="left">Layout Type Name</th>
	<texttable title="Initial Layout Type Assignments" anchor='layoutlist'>		<th align="left">Value</th>
			<th align="left">RFC</th>
	<ttcol>Layout Type Name</ttcol>		<th align="left">How</th>
	<ttcol>Value</ttcol>		<th align="left">Minor Versions</th>
	<ttcol>RFC</ttcol>		</tr>
	<ttcol>How</ttcol>		</thead>
	<ttcol>Minor Versions</ttcol>		<tbody>
			<tr>
	<c>LAYOUT4_NFSV4_1_FILES</c> <c>0x1</c> <c>RFC 5661</c> <c>N</c> <c>1</c		<td align="left">LAYOUT4_NFSV4_1_FILES</td>
	>		<td align="left">0x1</td>
			<td align="left">RFC 8881</td>
	<c>LAYOUT4_OSD2_OBJECTS</c> <c>0x2</c> <c>RFC 5664</c> <c>L</c> <c>1</c>		<td align="left">N</td>
	<c>LAYOUT4_BLOCK_VOLUME</c> <c>0x3</c> <c>RFC 5663</c> <c>L</c> <c>1</c>		<td align="left">1</td>
	<!-- [rfced] The IANA site lists this document (RFC 5661) as the		</tr>
	reference for values 0x2 and 0x3, instead of RFCs 5664 and 5663,		<tr>
	respectively. Does the IANA site need to be updated?		<td align="left">LAYOUT4_OSD2_OBJECTS</td>
			<td align="left">0x2</td>
	[Eisler]: The IANA site needs to be updated. -->		<td align="left">RFC 5664</td>
	</texttable>		<td align="left">L</td>
			<td align="left">1</td>
	</section>		</tr>
			<tr>
	<section title="Updating Registrations">		<td align="left">LAYOUT4_BLOCK_VOLUME</td>
	<t>		<td align="left">0x3</td>
			<td align="left">RFC 5663</td>
			<td align="left">L</td>
			<td align="left">1</td>
			</tr>
			</tbody>
			</table>
			</section>
			<section numbered="true" toc="default">
			<name>Updating Registrations</name>
			<t>
	The update of a registration will require IESG		The update of a registration will require IESG
	Approval on the advice of a Designated Expert.		Approval on the advice of a Designated Expert.
	</t>		</t>
			</section>
	</section>		<section anchor="layout_guidelines" numbered="true" toc="default">
			<name>Guidelines for Writing Layout Type Specifications</name>
	<section anchor="layout_guidelines" title="Guidelines for Writing Layout Typ		<t>
	e Specifications">
	<t>
	The author of a new pNFS layout specification must follow these		The author of a new pNFS layout specification must follow these
	steps to obtain acceptance of the layout type as a Standards Track RFC:		steps to obtain acceptance of the layout type as a Standards Track RFC:
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	The author devises the new layout specification.		The author devises the new layout specification.
	</t>		</li>
	<t>		<li>
	The new layout type specification MUST, at a minimum:		<t>
	<list style='symbols'>		The new layout type specification <bcp14>MUST</bcp14>, at a minimum:
	<t>		</t>
			<ul spacing="normal">
			<li>
			<t>
	Define the contents of the layout-type-specific fields of the		Define the contents of the layout-type-specific fields of the
	following data types:		following data types:
	<list style='symbols'>		</t>
	<t>		<ul spacing="normal">
			<li>
	the da_addr_body field of the device_addr4		the da_addr_body field of the device_addr4
	data type;		data type;
	</t>		</li>
	<t>		<li>
	the loh_body field of the layouthint4		the loh_body field of the layouthint4
	data type;		data type;
	</t>		</li>
	<t>		<li>
	the loc_body field of layout_content4		the loc_body field of layout_content4
	data type (which in turn is the lo_content field of the		data type (which in turn is the lo_content field of the
	layout4 data type);		layout4 data type);
	</t>		</li>
	<t>		<li>
	the lou_body field of the layoutupdate4		the lou_body field of the layoutupdate4
	data type;		data type;
	</t>		</li>
	</list>		</ul>
	</t>		</li>
	<t>		<li>
	Describe or define the storage access protocol used to access		Describe or define the storage access protocol used to access
	the storage devices.		the storage devices.
	</t>		</li>
	<t>		<li>
	Describe whether revocation of layouts is supported.		Describe whether revocation of layouts is supported.
	</t>		</li>
	<t>		<li>
			<t>
	At a minimum, describe the methods of recovery from:		At a minimum, describe the methods of recovery from:
	<list style="numbers">		</t>
	<t> Failure and restart for client, server, storage device.		<ol spacing="normal" type="1">
	</t>		<li> Failure and restart for client, server, storage device.
	<t> Lease expiration from perspective of the active client,		</li>
			<li> Lease expiration from perspective of the active client,
	server, storage device.		server, storage device.
	</t>		</li>
	<t> Loss of layout state resulting in fencing of client		<li> Loss of layout state resulting in fencing of client
	access to storage devices (for an example, see		access to storage devices (for an example, see
	<xref target="lease_expiration_mds" />).		<xref target="lease_expiration_mds" format="default"/>).
	</t>		</li>
	</list>		</ol>
	</t>		</li>
	<t>		<li>
			<t>
	Include an IANA considerations section, which will		Include an IANA considerations section, which will
	in turn include:		in turn include:
			</t>
	<list style="symbols">		<ul spacing="normal">
	<t>		<li>
	A request to IANA		A request to IANA
	for a new layout type per <xref		for a new layout type per <xref target="pnfsiana" format="default
	target="pnfsiana"/>.		"/>.
			</li>
	</t>		<li>
	<t>
	A list of requests to IANA for		A list of requests to IANA for
	any new recallable object types for		any new recallable object types for
	CB_RECALL_ANY; each entry is to be presented in the form describe d		CB_RECALL_ANY; each entry is to be presented in the form describe d
	in <xref target="recalliana"/>.		in <xref target="recalliana" format="default"/>.
			</li>
	</t>		<li>
	<t>
	A list of requests to IANA for		A list of requests to IANA for
	any new notification values for		any new notification values for
	CB_NOTIFY_DEVICEID; each entry is to be presented in the form		CB_NOTIFY_DEVICEID; each entry is to be presented in the form
	described in <xref target="notifyiana"/>.		described in <xref target="notifyiana" format="default"/>.
			</li>
	</t>		</ul>
	</list>		</li>
			<li>
	</t>		Include a security considerations section. This section <bcp14>MUST
	<t>		</bcp14>
	Include a security considerations section. This section MUST
	explain how the NFSv4.1 authentication, authorization, and		explain how the NFSv4.1 authentication, authorization, and
	access-control models are preserved. That is, if a metadata server		access-control models are preserved. That is, if a metadata server
	would restrict a READ or WRITE operation, how would pNFS via		would restrict a READ or WRITE operation, how would pNFS via
	the layout similarly restrict a corresponding input or		the layout similarly restrict a corresponding input or
	output operation?		output operation?
	</t>		</li>
			</ul>
	</list>		</li>
	</t>		<li>
	<t>
	The author documents the new layout specification as an Internet-Draft.		The author documents the new layout specification as an Internet-Draft.
	</t>		</li>
	<t>
			<li>
	The author submits the Internet-Draft for review through the		The author submits the Internet-Draft for review through the
	IETF standards process as defined in "The Internet Standards		IETF standards process as defined in "The Internet Standards
	Process--Revision 3" (BCP 9).		Process--Revision 3" (BCP 9 <xref target="BCP09" format="default"/>).
			The new layout specification will be
	The new layout specification will be
	submitted for eventual publication as a Standards Track RFC.		submitted for eventual publication as a Standards Track RFC.
	</t>		</li>
	<t>		<li>
	The layout specification progresses through the IETF standards		The layout specification progresses through the IETF standards
	process.		process.
	</t>		</li>
	</list>		</ol>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="path_var_iana" numbered="true" toc="default">
			<name>Path Variable Definitions</name>
	<section anchor="path_var_iana" title="Path Variable Definitions">		<t>
	<t>
	This section deals with the IANA considerations associated with		This section deals with the IANA considerations associated with
	the variable substitution feature for location names as		the variable substitution feature for location names as
	described in <xref target="SEC11-fsli-item" />. As		described in <xref target="SEC11-fsli-item" format="default"/>. As
	described there, variables subject to substitution consist		described there, variables subject to substitution consist
	of a domain name and a specific name within that domain, with the		of a domain name and a specific name within that domain, with the
	two separated by a colon. There are two sets of IANA considerations		two separated by a colon. There are two sets of IANA considerations
	here:		here:
	<list style='numbers'>
	<t>
	The list of variable names.
	</t>		</t>
			<ol spacing="normal" type="1">
	<t>		<li>
			The list of variable names.
			</li>
			<li>
	For each variable name, the list of possible values.		For each variable name, the list of possible values.
	</t>		</li>
			</ol>
	</list>		<t>
	Thus, there will be one registry for the list of variable names, and		Thus, there will be one registry for the list of variable names, and
	possibly one registry for listing the values of each variable name.		possibly one registry for listing the values of each variable name.
	</t>		</t>
			<section anchor="path_variables_iana" numbered="true" toc="default">
	<section anchor="path_variables_iana" title="Path Variables Registry">		<name>Path Variables Registry</name>
	<t>		<t>
	IANA created a registry called the "NFSv4 Path Variables Registry".		IANA created a registry called the "NFSv4 Path Variables Registry".
	</t>		</t>
			<section anchor="path_values_iana" numbered="true" toc="default">
	<section anchor="path_values_iana" title="Path Variable Values">		<name>Path Variable Values</name>
	<t>		<t>
	Variable names are of the form "${", followed by a		Variable names are of the form "${", followed by a
	domain name, followed by a colon (":"), followed by		domain name, followed by a colon (":"), followed by
	a domain-specific portion of the variable name,		a domain-specific portion of the variable name,
	followed by "}". When the domain name is "ietf.org",		followed by "}". When the domain name is "ietf.org",
	all variables names must be registered with IANA on		all variables names must be registered with IANA on
	a Standards Action basis, with Expert Review		a Standards Action basis, with Expert Review
	required. Path variables with registered domain		required. Path variables with registered domain
	names neither part of nor equal to ietf.org are		names neither part of nor equal to ietf.org are
	assigned on a Hierarchical Allocation basis		assigned on a Hierarchical Allocation basis
	(delegating to the domain owner) and thus of no		(delegating to the domain owner) and thus of no
	skipping to change at line 42776 ¶		skipping to change at line 42596 ¶
	domain owner chooses to do so, IANA will do so on a		domain owner chooses to do so, IANA will do so on a
	First Come First Serve basis. To accommodate		First Come First Serve basis. To accommodate
	registrants who do not have their own domain, IANA		registrants who do not have their own domain, IANA
	will accept requests to register variables with the		will accept requests to register variables with the
	prefix "${FCFS.ietf.org:" on a First Come First		prefix "${FCFS.ietf.org:" on a First Come First
	Served basis. Assignments on a First Come First Basis		Served basis. Assignments on a First Come First Basis
	do not require Expert Review, unless the registrant also		do not require Expert Review, unless the registrant also
	wants IANA to establish a registry for the values of the		wants IANA to establish a registry for the values of the
	registered variable.		registered variable.
	</t>		</t>
			<t>
	<t>
	The registry is a list of assignments, each		The registry is a list of assignments, each
	containing three fields.		containing three fields.
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	The name of the variable. The name of this		The name of the variable. The name of this
	variable must start with a "${" followed by a		variable must start with a "${" followed by a
	registered domain name, followed by ":", or it		registered domain name, followed by ":", or it
	must start with "${FCFS.ietf.org". The name must		must start with "${FCFS.ietf.org". The name must
	be no more than 64 UTF-8 characters long. The		be no more than 64 UTF-8 characters long. The
	name must be unique.		name must be unique.
	</t>		</li>
			<li>
	<t>
	For assignments made on Standards Action basis,		For assignments made on Standards Action basis,
	the Standards Track RFC(s) that describe the		the Standards Track RFC(s) that describe the
	variable. If the RFC(s) have not yet been		variable. If the RFC(s) have not yet been
	published, the registrant will use RFCTBD1,		published, the registrant will use RFCTBD1,
	RFCTBD2, etc. instead of an actual RFC number.		RFCTBD2, etc. instead of an actual RFC number.
	Note that the RFCs do not have to be a part of an NFS minor version.		Note that the RFCs do not have to be a part of an NFS minor version.
	For assignments made on a First Come First Serve basis, an explanation		For assignments made on a First Come First Serve basis, an explanation
	(consuming no more than 1024 bytes, or more if IANA permits)		(consuming no more than 1024 bytes, or more if IANA permits)
	of the purpose of the variable. A reference to the explanation can		of the purpose of the variable. A reference to the explanation can
	be substituted.		be substituted.
	</t>		</li>
	<t>		<li>
	The point of contact, including an email address. The point of		The point of contact, including an email address. The point of
	contact can consume up to 256 bytes (or more if IANA permits).		contact can consume up to 256 bytes (or more if IANA permits).
	For assignments made on a Standards Action basis, the point of		For assignments made on a Standards Action basis, the point of
	contact is always IESG.		contact is always IESG.
	</t>		</li>
			</ol>
	</list>		<section numbered="true" toc="default">
	</t>		<name>Initial Registry</name>
			<t>
	<section title="Initial Registry">		The initial registry is in <xref target="varlist" format="default"/>.
	<t>		</t>
	The initial registry is in <xref target="varlist"/>.		<table anchor="varlist" align="center">
	</t>		<name>Initial List of Path Variables</name>
			<thead>
	<texttable title="Initial List of Path Variables" anchor='varlist'>		<tr>
			<th align="left">Variable Name</th>
	<ttcol>Variable Name</ttcol>		<th align="left">RFC</th>
	<ttcol>RFC</ttcol>		<th align="left">Point of Contact</th>
	<ttcol>Point of Contact</ttcol>		</tr>
			</thead>
	<c>${ietf.org:CPU_ARCH}</c> <c>RFC 5661</c> <c>IESG</c>		<tbody>
	<c>${ietf.org:OS_TYPE}</c> <c>RFC 5661</c> <c>IESG</c>		<tr>
	<c>${ietf.org:OS_VERSION}</c> <c>RFC 5661</c> <c>IESG</c>		<td align="left">${ietf.org:CPU_ARCH}</td>
			<td align="left">RFC 8881</td>
	</texttable>		<td align="left">IESG</td>
			</tr>
	<t>		<tr>
			<td align="left">${ietf.org:OS_TYPE}</td>
			<td align="left">RFC 8881</td>
			<td align="left">IESG</td>
			</tr>
			<tr>
			<td align="left">${ietf.org:OS_VERSION}</td>
			<td align="left">RFC 8881</td>
			<td align="left">IESG</td>
			</tr>
			</tbody>
			</table>
			<t>
	IANA has created registries for the values		IANA has created registries for the values
	of the variable names ${ietf.org:CPU_ARCH} and		of the variable names ${ietf.org:CPU_ARCH} and
	${ietf.org:OS_TYPE}. See Sections <xref target="cpu_arch"		${ietf.org:OS_TYPE}. See Sections <xref target="cpu_arch" format="counter
	format="counter" />		"/>
	and <xref target="os_type" format="counter" />.		and <xref target="os_type" format="counter"/>.
	</t>		</t>
	<t>		<t>
	For the values of the variable		For the values of the variable
	${ietf.org:OS_VERSION}, no registry is needed as		${ietf.org:OS_VERSION}, no registry is needed as
	the specifics of the values of the variable will		the specifics of the values of the variable will
	vary with the value of ${ietf.org:OS_TYPE}. Thus,		vary with the value of ${ietf.org:OS_TYPE}. Thus,
	values for ${ietf.org:OS_VERSION} are on a		values for ${ietf.org:OS_VERSION} are on a
	Hierarchical Allocation basis and are of no concern		Hierarchical Allocation basis and are of no concern
	to IANA.		to IANA.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="Updating Registrations">		<name>Updating Registrations</name>
	<t>		<t>
	The update of an assignment made on a Standards Action basis		The update of an assignment made on a Standards Action basis
	will require IESG Approval on the advice of a Designated Expert.		will require IESG Approval on the advice of a Designated Expert.
	</t>		</t>
			<t>
	<t>
	The registrant can always update the point of contact of an assignment		The registrant can always update the point of contact of an assignment
	made on a First Come First Serve basis. Any other update will require		made on a First Come First Serve basis. Any other update will require
	Expert Review.		Expert Review.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		</section>
	</section>		<section anchor="cpu_arch" numbered="true" toc="default">
	<section title="Values for the ${ietf.org:CPU_ARCH} Variable" anchor="cpu_arch		<name>Values for the ${ietf.org:CPU_ARCH} Variable</name>
	">		<t>
	<t>
	IANA created a registry called the "NFSv4 ${ietf.org:CPU_ARCH} Value Regist ry".		IANA created a registry called the "NFSv4 ${ietf.org:CPU_ARCH} Value Regist ry".
	</t>		</t>
			<t>
	<t>
	Assignments to the registry are made on a First Come First Serve		Assignments to the registry are made on a First Come First Serve
	basis. The zero-length value of ${ietf.org:CPU_ARCH} is Reserved.		basis. The zero-length value of ${ietf.org:CPU_ARCH} is Reserved.
	Values with a prefix of "PRIV" are designated for Private Use.		Values with a prefix of "PRIV" are designated for Private Use.
	</t>		</t>
			<t>
	<t>
	The registry is a list of assignments, each		The registry is a list of assignments, each
	containing three fields.		containing three fields.
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	A value of the ${ietf.org:CPU_ARCH} variable. The value		A value of the ${ietf.org:CPU_ARCH} variable. The value
	must be 1 to 32 UTF-8 characters long. The value must be unique.		must be 1 to 32 UTF-8 characters long. The value must be unique.
	</t>		</li>
			<li>
	<t>
	An explanation (consuming no more than 1024		An explanation (consuming no more than 1024
	bytes, or more if IANA permits) of what CPU		bytes, or more if IANA permits) of what CPU
	architecture the value denotes. A reference to		architecture the value denotes. A reference to
	the explanation can be substituted.		the explanation can be substituted.
	</t>		</li>
			<li>
	<t>
	The point of contact, including an email address. The point of		The point of contact, including an email address. The point of
	contact can consume up to 256 bytes (or more if IANA permits).		contact can consume up to 256 bytes (or more if IANA permits).
	</t>		</li>
			</ol>
	</list>		<section numbered="true" toc="default">
	</t>		<name>Initial Registry</name>
			<t>
	<section title="Initial Registry">
	<t>
	There is no initial registry.		There is no initial registry.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="Updating Registrations">		<name>Updating Registrations</name>
	<t>		<t>
	The registrant is free to update the assignment, i.e., change the		The registrant is free to update the assignment, i.e., change the
	explanation and/or point-of-contact fields.		explanation and/or point-of-contact fields.
	</t>		</t>
			</section>
	</section>		</section>
	</section>		<section anchor="os_type" numbered="true" toc="default">
	<section title="Values for the ${ietf.org:OS_TYPE} Variable" anchor="os_type">		<name>Values for the ${ietf.org:OS_TYPE} Variable</name>
	<t>		<t>
	IANA created a registry called the "NFSv4 ${ietf.org:OS_TYPE} Value Registr y".		IANA created a registry called the "NFSv4 ${ietf.org:OS_TYPE} Value Registr y".
	</t>		</t>
			<t>
	<t>
	Assignments to the registry are made on a First Come First Serve		Assignments to the registry are made on a First Come First Serve
	basis. The zero-length value of ${ietf.org:OS_TYPE} is Reserved.		basis. The zero-length value of ${ietf.org:OS_TYPE} is Reserved.
	Values with a prefix of "PRIV" are designated for Private Use.		Values with a prefix of "PRIV" are designated for Private Use.
	</t>		</t>
			<t>
	<t>
	The registry is a list of assignments, each		The registry is a list of assignments, each
	containing three fields.		containing three fields.
	<list style='numbers'>		</t>
	<t>		<ol spacing="normal" type="1">
			<li>
	A value of the ${ietf.org:OS_TYPE} variable. The value		A value of the ${ietf.org:OS_TYPE} variable. The value
	must be 1 to 32 UTF-8 characters long. The value must be unique.		must be 1 to 32 UTF-8 characters long. The value must be unique.
	</t>		</li>
			<li>
	<t>
	An explanation (consuming no more than 1024		An explanation (consuming no more than 1024
	bytes, or more if IANA permits) of what CPU		bytes, or more if IANA permits) of what CPU
	architecture the value denotes. A reference to		architecture the value denotes. A reference to
	the explanation can be substituted.		the explanation can be substituted.
	</t>		</li>
			<li>
	<t>
	The point of contact, including an email address. The point of		The point of contact, including an email address. The point of
	contact can consume up to 256 bytes (or more if IANA permits).		contact can consume up to 256 bytes (or more if IANA permits).
	</t>		</li>
			</ol>
	</list>		<section numbered="true" toc="default">
	</t>		<name>Initial Registry</name>
			<t>
	<section title="Initial Registry">
	<t>
	There is no initial registry.		There is no initial registry.
	</t>		</t>
	</section>		</section>
			<section numbered="true" toc="default">
	<section title="Updating Registrations">		<name>Updating Registrations</name>
	<t>		<t>
	The registrant is free to update the assignment, i.e., change the		The registrant is free to update the assignment, i.e., change the
	explanation and/or point of contact fields.		explanation and/or point of contact fields.
	</t>		</t>
			</section>
			</section>
	</section>		</section>
			</section>
	</section>
	</section>
	</section>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->
	<!-- Copyright (C) The IETF Trust (2007) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	</middle>		</middle>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp
	$ -->
	<!-- Copyright (C) The IETF Trust (2007) -->
	<!-- Copyright (C) The Internet Society (2006) -->
	<back>		<back>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<references>
	$ -->		<name>References</name>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<references>
	<!-- Copyright (C) The Internet Society (2006) -->		<name>Normative References</name>
	<references title="Normative References">		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<reference anchor='RFC2119'>		FC.2119.xml"/>
	<front>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<title abbrev='RFC Key Words'>Key words for use in RFCs to Indicate Requi		FC.4506.xml"/>
	rement Levels</title>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<author initials='S.' surname='Bradner' fullname='Scott Bradner'>		FC.5531.xml"/>
	<organization>Harvard University</organization>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<address>		FC.2203.xml"/>
	<postal>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<street>1350 Mass. Ave.</street>		FC.4121.xml"/>
	<street>Cambridge</street>
	<street>MA 02138</street></postal>
	<phone>- +1 617 495 3864</phone>
	<email>sob@harvard.edu</email></address></author>
	<date year='1997' month='March' />
	</front>
	<seriesInfo name='BCP' value='14' />
	<seriesInfo name='RFC' value='2119' />
	<format type='TXT' target='http://www.rfc-editor.org/rfc/rfc2119.txt' />
	</reference>
	<reference anchor='RFC4506'>
	<front>
	<title>XDR: External Data Representation Standard</title>
	<author initials='M.' surname='Eisler' fullname='M. Eisler' role='editor'>
	<organization /></author>
	<date year='2006' month='May' />
	<abstract>
	<t>&lt;p>This document describes the External Data
	Representation Standard (XDR) protocol as it is currently
	deployed and accepted. This document obsoletes RFC
	1832. [STANDARDS TRACK]&lt;/p></t></abstract></front>
	<seriesInfo name='STD' value='67' />
	<seriesInfo name='RFC' value='4506' />
	<format type='TXT' octets='55477' target='http://www.rfc-editor.org/rfc/rf
	c4506.txt' />
	</reference>
	<reference anchor='RFC5531'>
	<front>
	<title>
	RPC: Remote Procedure Call Protocol Specification Version 2
	</title>
	<author initials='R.' surname='Thurlow' fullname='R. Thurlow'>
	<organization />
	</author>
	<date year='2009' month='May' />
	<abstract>
	<t>This document describes the Open Network Computing (ONC) Remote
	Procedure Call (RPC) version 2 protocol as it is currently deployed
	and accepted. This document obsoletes RFC 1831. [STANDARDS
	TRACK]</t></abstract></front>
	<seriesInfo name='RFC' value='5531' />
	<format type='TXT' octets='161720'
	target='ftp://ftp.isi.edu/in-notes/rfc5531.txt' />
	</reference>
	<reference anchor='RFC2203'>
	<front>
	<title>RPCSEC_GSS Protocol Specification</title>
	<author initials='M.' surname='Eisler' fullname='Michael Eisler'>
	<organization>Sun Microsystems, Inc.</organization>
	<address>
	<postal>
	<street>M/S UCOS03</street>
	<street>2550 Garcia Avenue</street>
	<street>Mountain View</street>
	<street>CA 94043</street></postal>
	<phone>+1 (719) 599-9026</phone>
	<email>mre@eng.sun.com</email></address></author>
	<author initials='A.' surname='Chiu' fullname='Alex Chiu'>
	<organization>Sun Microsystems, Inc.</organization>
	<address>
	<postal>
	<street>M/S UMPK17-203</street>
	<street>2550 Garcia Avenue</street>
	<street>Mountain View</street>
	<street>CA 94043</street></postal>
	<phone>+1 (415) 786-6465</phone>
	<email>hacker@eng.sun.com</email></address></author>
	<author initials='L.' surname='Ling' fullname='Lin Ling'>
	<organization>Sun Microsystems, Inc.</organization>
	<address>
	<postal>
	<street>M/S UMPK17-201</street>
	<street>2550 Garcia Avenue</street>
	<street>Mountain View</street>
	<street>CA 94043</street></postal>
	<phone>+1 (415) 786-5084</phone>
	<email>lling@eng.sun.com</email></address></author>
	<date year='1997' month='September' />
	<area>Security</area>
	<keyword>generic security service</keyword>
	<keyword>remote procedure call</keyword>
	<keyword>security</keyword>
	<abstract>
	<t>
	This memo describes an ONC/RPC security flavor that allows RPC
	protocols to access the Generic Security Services Application
	Programming Interface (referred to henceforth as GSS-API).
	</t></abstract></front>
	<seriesInfo name='RFC' value='2203' />
	<format type='TXT' octets='50937' target='http://www.rfc-editor.org/rfc/rf
	c2203.txt' />
	<format type='HTML' octets='64234' target='http://xml.resource.org/public/
	rfc/html/rfc2203.html' />
	<format type='XML' octets='50069' target='http://xml.resource.org/public/r
	fc/xml/rfc2203.xml' />
	</reference>
	<reference anchor='RFC4121'>
	<front>
	<title>The Kerberos Version 5 Generic Security Service Application Progr
	am Interface (GSS-API) Mechanism Version 2</title>
	<author initials='L.' surname='Zhu'>
	<organization>Microsoft</organization>
	</author>
	<author initials='K.' surname='Jaganathan'>
	<organization>Microsoft</organization>
	</author>
	<author initials='S.' surname='Hartman'>
	<organization>MIT</organization>
	</author>
	<date year='2005' month='July' />
	<abstract>
	<t>
	RFC 1964 is updated and incremental changes are proposed in
	response to recent developments such as the introduction of
	Kerberos crypto-system framework. These changes support the
	inclusion of new crypto-systems, by defining new per-message
	tokens along with their encryption and checksum algorithms
	based on the crypto-system profiles.
	</t>
	</abstract>
	</front>
	<seriesInfo name='RFC' value='4121' />
	<format type='TXT' target='http://www.rfc-editor.org/rfc/rfc4121.txt' />
	</reference>
	<reference anchor="hardlink">
	<front>
	<title abbrev="Open Group">
	Section 3.191 of Chapter 3 of Base Definitions of
	The Open Group Base Specifications Issue 6
	IEEE Std 1003.1, 2004 Edition, HTML Version (www.opengroup.org), ISBN
	1931624232 </title>
	<author>
	<organization>The Open Group </organization>
	</author>
	<date year="2004"/>
	</front>
	</reference>
	<reference anchor='RFC2743'>
	<front>
	<title abbrev='GSS-API'>Generic Security Service Application
	Program Interface Version 2, Update 1</title>
	<author initials='J.' surname='Linn' fullname='John Linn'>
	<organization>RSA Laboratories</organization>
	<address>
	<postal>
	<street>20 Crosby Drive</street>
	<city>Bedford</city>
	<region>MA</region>
	<code>01730</code>
	<country>US</country></postal>
	<phone>+1 781 687 7817</phone>
	<email>jlinn@rsasecurity.com</email></address></author>
	<date year='2000' month='January' />
	<abstract>
	<t>The Generic Security Service Application Program
	Interface (GSS-API), Version 2, as defined in, provides
	security services to callers in a generic fashion,
	supportable with a range of underlying mechanisms and
	technologies and hence allowing source-level portability of
	applications to different environments. This specification
	defines GSS-API services and primitives at a level
	independent of underlying mechanism and programming language
	environment, and is to be complemented by other, related
	specifications:</t>
	<t>documents defining specific parameter bindings for
	particular language environments</t>
	<t>documents defining token formats, protocols, and
	procedures to be implemented in order to realize GSS-API
	services atop particular security mechanisms</t> <t>This
	memo obsoletesmaking specific, incremental changes in
	response to implementation experience and liaison
	requests. It is intended, therefore, that this memo or a
	successor version thereto will become the basis for
	subsequent progression of the GSS-API specification on the
	standards track.</t></abstract></front>
	<seriesInfo name='RFC' value='2743' />
	<format type='TXT' octets='229418'
	target='http://www.rfc-editor.org/rfc/rfc2743.txt' />
	</reference>
	<reference anchor='RDMAP'>
	<front>
	<title abbrev='RDMAP - WIP'>A Remote Direct Memory Access Protocol
	Specification
	</title>
	<author initials='R.' surname='Recio'>
	<organization>IBM Corporation</organization>
	</author>
	<author initials='B.' surname='Metzler'>
	<organization>IBM Corporation</organization>
	</author>
	<author initials='P.' surname='Culley'>
	<organization>Hewlett-Packard Company</organization>
	</author>
	<author initials='J.' surname='Hilland'>
	<organization>Hewlett-Packard Company</organization>
	</author>
	<author initials='D.' surname='Garcia'>
	<organization></organization>
	</author>
	<date year='2007' month='October' />
	<abstract>
	<t>
	This document defines a Remote Direct Memory Access Protocol
	(RDMAP) that operates over the Direct Data Placement Protocol (DDP
	protocol). RDMAP provides read and write services directly to
	applications and enables data to be transferred directly into
	Upper Layer Protocol (ULP) buffers without intermediate data
	copies. It also enables a kernel bypass implementation.
	</t></abstract></front>
	<seriesInfo name='RFC' value='5040' />
	<format type='TXT' target='http://www.rfc-editor.org/rfc/rfc5040.txt' />
	</reference>
	<reference anchor='RFC5403'>
	<front>
	<title>RPCSEC_GSS Version 2</title>
	<author initials='M.' surname='Eisler' fullname='M. Eisler'>
	<organization /></author>
	<date year='2009' month='February' />
	<abstract>
	<t>This document describes version 2 of the RPCSEC_GSS protocol. Version
	2 is the same as version 1 (specified in RFC 2203) except that support for chan
	nel bindings has been added. RPCSEC_GSS allows remote procedure call (RPC) prot
	ocols to access the Generic Security Services Application Programming Interface
	(GSS-API). [STANDARDS TRACK]</t></abstract></front>
	<seriesInfo name='RFC' value='5403' />
	<format type='TXT' octets='30812' target='ftp://ftp.isi.edu/in-notes/rfc5
	403.txt' />
	</reference>
	<reference anchor='RFC5662'>
	<front>
	<title>
	Network File System (NFS) Version 4 Minor Version 1 External Data
	Representation Standard (XDR) Description
	</title>
	<author initials='S' surname='Shepler' fullname='Spencer Shepler' role='editor'>
	<organization />
	</author>
	<author initials='M' surname='Eisler' fullname='Mike Eisler' role='editor'>
	<organization />
	</author>
	<author initials='D' surname='Noveck' fullname='David Noveck' role='editor'>
	<organization />
	</author>
	<date month='January' year='2010' />
	<abstract><t>This Internet-Draft provides the XDR description for NFSv4 minor ve
	rsion one.</t></abstract>
	</front>
	<seriesInfo name='RFC' value='5662' />
	</reference>
	<reference anchor="symlink">
	<front>
	<title>Section 3.372 of Chapter 3 of Base Definitions of
	The Open Group Base Specifications Issue 6
	IEEE Std 1003.1, 2004 Edition, HTML Version (www.opengroup.org), ISBN
	1931624232 </title>
	<author>
	<organization>The Open Group </organization>
	</author>
	<date year="2004"/>
	</front>
	</reference>
	<reference anchor='RFC5665'>
	<front>
	<title>
	IANA Considerations for Remote Procedure Call (RPC) Network
	Identifiers and Universal Address Formats
	</title>
	<author initials='M' surname='Eisler' fullname='Mike Eisler'>
	<organization />
	</author>
	<date month='January' year='2010' />
	<abstract>
	<t>
	IANA Considerations for RPC Net Identifiers and Universal Address Formats.
	</t>
	</abstract>
	</front>
	<seriesInfo name='RFC' value='5665' />
	</reference>
	<reference anchor="read_atime">
	<front>
	<title>Section 'read()' of System Interfaces of
	The Open Group Base Specifications Issue 6
	IEEE Std 1003.1, 2004 Edition, HTML Version (www.opengroup.org), ISBN
	1931624232 </title>
	<author>
	<organization>The Open Group </organization>
	</author>
	<date year="2004"/>
	</front>
	</reference>
	<reference anchor="readdir_atime">
	<front>
	<title>Section 'readdir()' of System Interfaces of
	The Open Group Base Specifications Issue 6
	IEEE Std 1003.1, 2004 Edition, HTML Version (www.opengroup.org), ISBN
	1931624232 </title>
	<author>
	<organization>The Open Group </organization>
	</author>
	<date year="2004"/>
	</front>
	</reference>
	<reference anchor="write_atime">
	<front>
	<title>Section 'write()' of System Interfaces of
	The Open Group Base Specifications Issue 6
	IEEE Std 1003.1, 2004 Edition, HTML Version (www.opengroup.org), ISBN
	1931624232 </title>
	<author>
	<organization>The Open Group </organization>
	</author>
	<date year="2004"/>
	</front>
	</reference>
	<reference anchor='RFC3454'>
	<front>
	<title>Preparation of Internationalized Strings ("stringprep")</title>
	<author initials='P.' surname='Hoffman' fullname='P. Hoffman'>
	<organization /></author>
	<author initials='M.' surname='Blanchet' fullname='M. Blanchet'>
	<organization /></author>
	<date year='2002' month='December' />
	<abstract>
	<t>
	&lt;p>This document describes a framework for preparing
	Unicode text strings in order to increase the likelihood
	that string input and string comparison work in ways that
	make sense for typical users throughout the world. The
	stringprep protocol is useful for protocol identifier
	values, company and personal names, internationalized
	domain names, and other text strings. This document does
	not specify how protocols should prepare text
	strings. Protocols must create profiles of stringprep in
	order to fully specify the processing options. [STANDARDS
	TRACK] &lt;/p>
	</t>
	</abstract>
	</front>
	<seriesInfo name='RFC' value='3454' />
	<format type='TXT' octets='138684' target='http://www.rfc-editor.org/rfc/r
	fc3454.txt' />
	</reference>
	<reference anchor="chmod">
	<front>
	<title>Section 'chmod()' of System Interfaces of
	The Open Group Base Specifications Issue 6
	IEEE Std 1003.1, 2004 Edition, HTML Version (www.opengroup.org), ISBN
	1931624232 </title>
	<author>
	<organization>The Open Group </organization>
	</author>
	<date year="2004"/>
	</front>
	</reference>
	<reference anchor="ISO.10646-1.1993">
	<front>
	<title>Information Technology - Universal Multiple-octet coded
	Character Set (UCS) - Part 1: Architecture and Basic Multilingual
	Plane</title>
	<author>
	<organization>International Organization for Standardization
	</organization>
	</author>
	<date month="May" year="1993" />
	</front>
	<seriesInfo name="ISO" value="Standard 10646-1" />
	</reference>
	<reference anchor='RFC2277'>
	<front>
	<title abbrev='Charset Policy'>
	IETF Policy on Character Sets and Languages</title>
	<author initials='H.' surname='Alvestrand'
	fullname='Harald Tveit Alvestrand'>
	<organization>UNINETT</organization>
	<address>
	<postal>
	<street>P.O.Box 6883 Elgeseter</street>
	<street>N-7002 TRONDHEIM</street>
	<country>NORWAY</country></postal>
	<phone>+47 73 59 70 94</phone>
	<email>Harald.T.Alvestrand@uninett.no</email></address></author>
	<date year='1998' month='January' />
	<area>Applications</area>
	<keyword>Internet Engineering Task Force</keyword>
	<keyword>character encoding</keyword></front>
	<seriesInfo name='BCP' value='18' />
	<seriesInfo name='RFC' value='2277' />
	<format type='TXT' octets='16622'
	target='http://www.rfc-editor.org/rfc/rfc2277.txt' />
	<format type='HTML' octets='26556'
	target='http://xml.resource.org/public/rfc/html/rfc2277.html' />
	<format type='XML' octets='15544'
	target='http://xml.resource.org/public/rfc/xml/rfc2277.xml' />
	</reference>
	<reference anchor='RFC3491'>
	<front>
	<title>Nameprep: A Stringprep Profile for Internationalized Domain Names
	(IDN)</title>
	<author initials='P.' surname='Hoffman' fullname='P. Hoffman'>
	<organization /></author>
	<author initials='M.' surname='Blanchet' fullname='M. Blanchet'>
	<organization /></author>
	<date year='2003' month='March' />
	<abstract>
	<t>
	&lt;p>This document describes how to prepare
	internationalized domain name (IDN) labels in order to
	increase the likelihood that name input and name
	comparison work in ways that make sense for typical users
	throughout the world. This profile of the stringprep
	protocol is used as part of a suite of on-the-wire
	protocols for internationalizing the Domain Name System
	(DNS). [STANDARDS TRACK] &lt;/p>
	</t>
	</abstract>
	</front>
	<seriesInfo name='RFC' value='3491' />
	<format type='TXT' octets='10316' target='http://www.rfc-editor.org/rfc/rf
	c3491.txt' />
	</reference>
	<reference anchor="fcntl">
	<front>
	<title>Section 'fcntl()' of System Interfaces of
	The Open Group Base Specifications Issue 6
	IEEE Std 1003.1, 2004 Edition, HTML Version (www.opengroup.org), ISBN
	1931624232 </title>
	<author>
	<organization>The Open Group </organization>
	</author>
	<date year="2004"/>
	</front>
	</reference>
	<reference anchor="fsync">
	<front>
	<title>Section 'fsync()' of System Interfaces of
	The Open Group Base Specifications Issue 6
	IEEE Std 1003.1, 2004 Edition, HTML Version (www.opengroup.org), ISBN
	1931624232 </title>
	<author>
	<organization>The Open Group </organization>
	</author>
	<date year="2004"/>
	</front>
	</reference>
	<reference anchor="passwd">
	<front>
	<title>Section 'getpwnam()' of System Interfaces of
	The Open Group Base Specifications Issue 6
	IEEE Std 1003.1, 2004 Edition, HTML Version (www.opengroup.org), ISBN
	1931624232 </title>
	<author>
	<organization>The Open Group </organization>
	</author>
	<date year="2004"/>
	</front>
	</reference>
	<reference anchor="unlink">
	<front>
	<title>Section 'unlink()' of System Interfaces of
	The Open Group Base Specifications Issue 6
	IEEE Std 1003.1, 2004 Edition, HTML Version (www.opengroup.org), ISBN
	1931624232 </title>
	<author>
	<organization>The Open Group </organization>
	</author>
	<date year="2004"/>
	</front>
	</reference>
	<!-- obsoleted by RFC 5531
	<reference anchor='RFC1831'>
	<front>
	<title abbrev='Remote Procedure Call Protocol Version 2'>RPC:
	Remote Procedure Call Protocol Specification Version 2</title>
	<author initials='R.' surname='Srinivasan' fullname='Raj Srinivasan'>
	<organization>Sun Microsystems, Inc., ONC Technologies</organization>
	<address>
	<postal>
	<street>2550 Garcia Avenue</street>
	<street>M/S MTV-5-40</street>
	<city>Mountain View</city>
	<region>CA</region>
	<code>94043</code>
	<country>US</country></postal>
	<phone>+1 415 336 2478</phone>
	<facsimile>+1 415 336 6015</facsimile>
	<email>raj@eng.sun.com</email></address></author>
	<date year='1995' month='August' />
	<abstract>
	<t>This document describes the ONC Remote Procedure Call (ONC
	RPC Version 2) protocol as it is currently deployed and
	accepted. "ONC" stands for "Open Network
	Computing".</t></abstract></front>
	<seriesInfo name='RFC' value='1831' />
	<format type='TXT' octets='37798' target='ftp://ftp.isi.edu/in-notes/rfc18
	31.txt' />
	</reference> -->
	<reference anchor='RFC4055'>
	<front>		<reference anchor="hardlink" target="https://www.opengroup.org">
	<title>		<front>
	Additional Algorithms and Identifiers for RSA Cryptography for use in		<title abbrev="Open Group">Section 3.191 of Chapter 3 of
	the Internet X.509 Public Key Infrastructure Certificate and		Base Definitions of The Open Group Base Specifications Issue 6
	Certificate Revocation List (CRL) Profile		IEEE Std 1003.1, 2004 Edition, HTML Version </title>
	</title>		<seriesInfo name="ISBN" value="1931624232"/>
	<author initials='J.' surname='Schaad' fullname='J. Schaad'>		<author>
	<organization /></author>		<organization>The Open Group </organization>
	<author initials='B.' surname='Kaliski' fullname='B. Kaliski'>		</author>
	<organization /></author>		<date year="2004"/>
	<author initials='R.' surname='Housley' fullname='R. Housley'>		</front>
	<organization /></author>		</reference>
	<date year='2005' month='June' />
	<abstract>
	<t>&lt;p>This document supplements RFC 3279. It describes the
	conventions for using the RSA Probabilistic Signature Scheme
	(RSASSA-PSS) signature algorithm, the RSA Encryption Scheme -
	Optimal Asymmetric Encryption Padding (RSAES-OAEP) key transport
	algorithm and additional one-way hash functions with the
	Public-Key Cryptography Standards (PKCS) #1 version 1.5 signature
	algorithm in the Internet X.509 Public Key Infrastructure
	(PKI). Encoding formats, algorithm identifiers, and parameter
	formats are specified. [STANDARDS
	TRACK]&lt;/p>
	</t>
	</abstract>
	</front>
	<seriesInfo name='RFC' value='4055' />		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<format type='TXT' octets='57479' target='http://www.rfc-editor.org/rfc/rfc4		FC.2743.xml"/>
	055.txt' />		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	</reference>		FC.5040.xml"/>
	<reference anchor="CSOR_AES">		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<front>		FC.5403.xml"/>
	<title>Cryptographic Algorithm Object Registration		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	</title>		FC.5662.xml"/>
	<author>
	<organization>National Institute of Standards and Technology
	</organization>
	</author>
	<date month="November" year="2007" />
	</front>
	<seriesInfo name="URL" value="http://csrc.nist.gov/groups/ST/crypto_apps_i
	nfra/csor/algorithms.html" />
	</reference>
	<?rfc include="reference.RFC.7861.xml"?>
	<?rfc include="reference.RFC.4120.xml"?>
	<?rfc include="reference.RFC.4033.xml"?>
	<?rfc include="reference.RFC.7858.xml"?>
	<?rfc include="reference.RFC.8000.xml"?>
	<?rfc include="reference.RFC.8166.xml"?>
	<?rfc include="reference.RFC.8267.xml"?>
	<?rfc include="reference.RFC.8484.xml"?>
	</references>
	<references title="Informative References">		<reference anchor="symlink" target="https://www.opengroup.org">
	<?rfc include="reference.I-D.roach-bis-documents.xml"?>		<front>
	<reference anchor='RFC3530'>		<title>Section 3.372 of Chapter 3 of
	<front>		Base Definitions of The Open Group Base Specifications Issue 6
	<title>Network File System (NFS) version 4 Protocol</title>		IEEE Std 1003.1, 2004 Edition, HTML Version </title>
	<author initials="S." surname="Shepler" fullname="S. Shepler">		<seriesInfo name="ISBN" value="1931624232"/>
	<organization>Sun Microsystems, Inc.</organization>		<author>
	</author>		<organization>The Open Group </organization>
	<author initials="B." surname="Callaghan" fullname="B. Callaghan">		</author>
	<organization>Sun Microsystems, Inc.</organization>		<date year="2004"/>
	</author>		</front>
	<author initials="D." surname="Robinson" fullname="D. Robinson">		</reference>
	<organization>Sun Microsystems, Inc.</organization>
	</author>
	<author initials="R." surname="Thurlow" fullname="R. Thurlow">
	<organization>Sun Microsystems, Inc.</organization>
	</author>
	<author initials="C." surname="Beame" fullname="C. Beame">
	<organization>Hummingbird, Ltd.</organization>
	</author>
	<author initials="M." surname="Eisler" fullname="M. Eisler">
	<organization>NetApp</organization>
	</author>
	<author initials="D." surname="Noveck" fullname="D. Noveck">
	<organization>NetApp</organization>
	</author>
	<date year="2003" month="April"/>
	</front>
	<seriesInfo name="RFC" value="3530"/>
	<format type="TXT" octets="600988"
	target="http://www.rfc-editor.org/rfc/rfc3530.txt"/>
	</reference>
	<reference anchor='RFC1813'>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R FC.5665.xml"/>
	<front>		<reference anchor="read_atime" target="https://www.opengroup.org">
	<title abbrev='NFSv3 Protocol'>NFS Version 3 Protocol Specification</title>		<front>
	<author initials='B.' surname='Callaghan' fullname='Brent Callaghan'>		<title>Section 'read()' of
	<organization>Sun Microsystems, Inc.</organization>		System Interfaces of The Open Group Base Specifications Issue 6
	<address>		IEEE Std 1003.1, 2004 Edition, HTML Version </title>
	<postal>		<seriesInfo name="ISBN" value="1931624232"/>
	<street>2550 Garcia Avenue</street>		<author>
	<street>Mailstop UMTV05-44</street>		<organization>The Open Group </organization>
	<city>Mountain View</city>		</author>
	<region>CA</region>		<date year="2004"/>
	<code>94043-1100</code>		</front>
	<country>US</country></postal>		</reference>
	<phone>+1 415 336 1051</phone>
	<facsimile>+1 415 336 6015</facsimile>
	<email>brent.callaghan@eng.sun.com</email></address></author>
	<author initials='B.' surname='Pawlowski' fullname='Brian Pawlowski'>		<reference anchor="readdir_atime" target="https://www.opengroup.org">
	<organization>NetApp</organization>		<front>
	<address>		<title>Section 'readdir()' of
	<postal>		System Interfaces of The Open Group Base Specifications Issue 6
	<street>319 North Bernardo Ave.</street>		IEEE Std 1003.1, 2004 Edition, HTML Version </title>
	<city>Mountain View</city>		<seriesInfo name="ISBN" value="1931624232"/>
	<region>CA</region>		<author>
	<code>94043</code>		<organization>The Open Group </organization>
	<country>US</country></postal>		</author>
	<phone>+1 415 428 5136</phone>		<date year="2004"/>
	<facsimile>+1 415 428 5151</facsimile>		</front>
	<email>beepy@netapp.com</email></address></author>		</reference>
	<author initials='P.' surname='Staubach' fullname='Peter Staubach'>		<reference anchor="write_atime" target="https://www.opengroup.org">
	<organization>Sun Microsystems, Inc.</organization>		<front>
	<address>		<title>Section 'write()' of
	<postal>		System Interfaces of The Open Group Base Specifications Issue 6
	<street>2550 Garcia Avenue</street>		IEEE Std 1003.1, 2004 Edition, HTML Version </title>
	<street>Mailstop UMTV05-44</street>		<seriesInfo name="ISBN" value="1931624232"/>
	<city>Mountain View</city>		<author>
	<region>CA</region>		<organization>The Open Group </organization>
	<code>94043-1100</code>		</author>
	<country>US</country></postal>		<date year="2004"/>
	<phone>+1 415 336 5615</phone>		</front>
	<facsimile>+1 415 336 6015</facsimile>		</reference>
	<email>peter.staubach@eng.sun.com</email></address></author>
	<date year='1995' month='June' />		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<abstract>		FC.3454.xml"/>
	<t>This paper describes the NFSv3 protocol. This paper is provided so that peop
	le can write compatible implementations.</t></abstract></front>
	<seriesInfo name='RFC' value='1813' />		<reference anchor="chmod" target="https://www.opengroup.org">
	<format type='TXT' octets='229793' target='http://www.rfc-editor.org/rfc/rfc1813		<front>
	.txt' />		<title>Section 'chmod()' of
	</reference>		System Interfaces of The Open Group Base Specifications Issue 6
			IEEE Std 1003.1, 2004 Edition, HTML Version </title>
			<seriesInfo name="ISBN" value="1931624232"/>
			<author>
			<organization>The Open Group </organization>
			</author>
			<date year="2004"/>
			</front>
			</reference>
	<reference anchor='RFC2847'>		<reference anchor="ISO.10646-1.1993">
			<front>
			<title>Information Technology -
			Universal Multiple-octet coded Character Set (UCS) -
			Part 1: Architecture and Basic Multilingual Plane </title>
			<seriesInfo name="ISO" value="Standard 10646-1"/>
			<author>
			<organization>International Organization for Standardization
			</organization>
			</author>
			<date month="May" year="1993"/>
			</front>
			</reference>
	<front>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<title>LIPKEY - A Low Infrastructure Public Key Mechanism Using SPKM</titl		FC.2277.xml"/>
	e>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<author initials='M.' surname='Eisler' fullname='M. Eisler'>		FC.3491.xml"/>
	<organization /></author>
	<date year='2000' month='June' />
	<abstract>		<reference anchor="fcntl" target="https://www.opengroup.org">
	<t>&lt;p>This memorandum describes a method whereby one can		<front>
	use GSS-API (Generic Security Service Application Program		<title>Section 'fcntl()' of
	Interface) to supply a secure channel between a client and		System Interfaces of The Open Group Base Specifications Issue 6
	server, authenticating the client with a password, and a		IEEE Std 1003.1, 2004 Edition, HTML Version </title>
	server with a public key certificate. [STANDARDS TRACK]		<seriesInfo name="ISBN" value="1931624232"/>
	&lt;/p></t>		<author>
	</abstract>		<organization>The Open Group </organization>
	</front>		</author>
			<date year="2004"/>
			</front>
			</reference>
	<seriesInfo name='RFC' value='2847' />		<reference anchor="fsync" target="https://www.opengroup.org">
	<format type='TXT' octets='50045' target='http://www.rfc-editor.org/rfc/rf		<front>
	c2847.txt' />		<title>Section 'fsync()' of
	</reference>		System Interfaces of The Open Group Base Specifications Issue 6
			IEEE Std 1003.1, 2004 Edition, HTML Version </title>
			<seriesInfo name="ISBN" value="1931624232"/>
			<author>
			<organization>The Open Group </organization>
			</author>
			<date year="2004"/>
			</front>
			</reference>
	<reference anchor='RFC2623'>		<reference anchor="passwd" target="https://www.opengroup.org">
			<front>
			<title>Section 'getpwnam()' of
			System Interfaces of The Open Group Base Specifications Issue 6
			IEEE Std 1003.1, 2004 Edition, HTML Version </title>
			<seriesInfo name="ISBN" value="1931624232"/>
			<author>
			<organization>The Open Group </organization>
			</author>
			<date year="2004"/>
			</front>
			</reference>
	<front>		<reference anchor="unlink" target="https://www.opengroup.org">
	<title abbrev='NFS Security, RPCSEC_GSS, and Kerberos V5'>		<front>
	NFS Version 2 and Version 3 Security Issues and the NFS Protocol's Use		<title>Section 'unlink()' of
	of RPCSEC_GSS and Kerberos V5		System Interfaces of The Open Group Base Specifications Issue 6
	</title>		IEEE Std 1003.1, 2004 Edition, HTML Version </title>
			<seriesInfo name="ISBN" value="1931624232"/>
			<author>
			<organization>The Open Group </organization>
			</author>
			<date year="2004"/>
			</front>
			</reference>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4
			055.xml"/>
	<author initials='M.' surname='Eisler' fullname='Mike Eisler'>		<reference anchor="CSOR_AES" target="https://csrc.nist.gov/projects/computer
	<organization>Sun Microsystems, Inc.</organization>		-security-objects-register/algorithm-registration">
	<address>		<front>
	<postal>		<title>Computer Security Objects Register
	<street>5565 Wilson Road</street>		</title>
	<city>Colorado Springs</city>		<author>
	<region>CO</region>		<organization>National Institute of Standards and Technology
	<code>80919</code>		</organization>
	<country>US</country></postal>		</author>
	<phone>+1 719 599 9026</phone>		<date month="May" year="2016"/>
	<email>mre@eng.sun.com</email></address></author>		</front>
			</reference>
	<date year='1999' month='June' />		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.7861.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.4120.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.4033.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.7858.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.8000.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.8166.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.8267.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.8484.xml"/>
	<abstract>		<referencegroup anchor="BCP09" target="https://www.rfc-editor.org/info/bcp
			9">
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RF
			C.2026.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RF
			C.7127.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RF
			C.5657.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RF
			C.6410.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RF
			C.7100.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RF
			C.7475.xml"/>
			</referencegroup>
	<t>This memorandum clarifies various security issues involving		</references>
	the NFSv2 and NFSv3 protocols and then
	describes how the NFS protocol
	use the RPCSEC_GSS security flavor protocol and Kerberos V5.
	This memorandum is provided so that people can write compatible
	implementations.</t>
	</abstract>
	</front>
	<seriesInfo name='RFC' value='2623' />		<references>
	<format type='TXT' octets='42521' target='http://www.rfc-editor.org/rfc/rf		<name>Informative References</name>
	c2623.txt' />		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml3/reference.
	</reference>		I-D.draft-roach-bis-documents-00.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.3530.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.1813.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.2847.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.2623.xml"/>
	<reference anchor="Chet">		<reference anchor="Chet">
	<front>		<front>
	<title>Improving the Performance		<title>Improving the Performance
	and Correctness of an NFS Server</title>		and Correctness of an NFS Server</title>
			<author initials="C." surname="Juszczak" fullname="Chet Juszczak">
	<author initials="C." surname="Juszczak" fullname="Chet Juszczak">		<organization>Digital Equipment Corporation</organization>
	<organization>Digital Equipment Corporation</organization>		</author>
	</author>		<date month="June" year="1990"/>
	<date month="June" year="1990"/>		<abstract>
	<abstract>		<t>
	<t>
	Describes reply cache implementation that		Describes reply cache implementation that
	avoids work in the server by handling		avoids work in the server by handling
	duplicate requests. More important, though		duplicate requests. More important, though
	listed as a side-effect, the reply cache		listed as a side-effect, the reply cache
	aids in the avoidance of destructive non-		aids in the avoidance of destructive non-
	idempotent operation re-application --		idempotent operation re-application --
	improving correctness.		improving correctness.
			</t>
			</abstract>
			</front>
			<refcontent>USENIX Conference Proceedings</refcontent>
			</reference>
	</t>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	</abstract>		FC.3232.xml"/>
	</front>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<seriesInfo name="USENIX Conference Proceedings" value="" />		FC.1833.xml"/>
	</reference>
	<reference anchor='RFC3232'>
	<front>
	<title>Assigned Numbers: RFC 1700 is Replaced by an On-line Database</ti
	tle>
	<author initials='J.' surname='Reynolds'
	fullname='J. Reynolds' role='editor'>
	<organization /></author>
	<date year='2002' month='January' />
	<abstract>
	<t>&lt;p>This memo obsoletes RFC 1700 (STD 2) "Assigned
	Numbers", which contained an October 1994 snapshot of assigned
	Internet protocol parameters. This memo provides information
	for the Internet community. &lt;/p></t>
	</abstract></front>
	<seriesInfo name='RFC' value='3232' />
	<format type='TXT' octets='3849' target='http://www.rfc-editor.org/rfc/rfc
	3232.txt' />
	</reference>
	<reference anchor='RFC1833'>
	<front>
	<title>Binding Protocols for ONC RPC Version 2</title>
	<author initials='R.' surname='Srinivasan' fullname='Raj Srinivasan'>
	<organization>Sun Microsystems, Inc., ONC Technologies</organization>
	<address>
	<postal>
	<street>2550 Garcia Avenue</street>
	<street>M/S MTV-5-40</street>
	<city>Mountain View</city>
	<region>CA</region>
	<code>94043</code>
	<country>US</country></postal>
	<phone>+1 415 336 2478</phone>
	<facsimile>+1 415 336 6015</facsimile>
	<email>raj@eng.sun.com</email></address></author>
	<date year='1995' month='August' />
	<abstract>
	<t>This document describes the binding protocols used in
	conjunction with the ONC Remote Procedure Call (ONC RPC Version
	2) protocols.</t></abstract></front>
	<seriesInfo name='RFC' value='1833' />
	<format type='TXT' octets='24449' target='http://www.rfc-editor.org/rfc/rf
	c1833.txt' />
	</reference>
	<reference anchor="rpc_xid_issues">
	<front>
	<title>RPC XID Issues</title>
	<author initials="R." surname="Werme" fullname="Ric Werme">		<reference anchor="rpc_xid_issues">
	<organization>Digital Equipment Corporation</organization>		<front>
	</author>		<title>RPC XID Issues</title>
	<date month="February" year="1996"/>		<author initials="R." surname="Werme" fullname="Ric Werme">
	<abstract>		<organization>Digital Equipment Corporation</organization>
	<t>		</author>
			<date month="February" year="1996"/>
			<abstract>
			<t>
	The presentation provides implementation advice for		The presentation provides implementation advice for
	ONC RPC transaction identifier (xid) generation.		ONC RPC transaction identifier (xid) generation.
	</t>		</t>
	</abstract>		</abstract>
	</front>		</front>
	<seriesInfo name="USENIX Conference Proceedings" value="" />		<refcontent>USENIX Conference Proceedings</refcontent>
	</reference>		</reference>
	<reference anchor='RFC1094'>
	<front>
	<title abbrev='NFS: Network File System'>NFS: Network File System Protocol speci
	fication</title>
	<author initials='B.' surname='Nowicki' fullname='Bill Nowicki'>
	<organization>Sun Microsystems, Inc.</organization>
	<address>
	<postal>
	<street>2550 Garcia Avenue</street>
	<street>Mail Stop 1-40</street>
	<city>Mountain View</city>
	<region>CA</region>
	<code>94043</code>
	<country>US</country></postal>
	<phone>+1 415 336 7278</phone>
	<email>nowicki@SUN.COM</email></address></author>
	<date year='1989' month='March' /></front>
	<seriesInfo name='RFC' value='1094' />
	<format type='TXT' octets='51454' target='http://www.rfc-editor.org/rfc/rfc1094.
	txt' />
	</reference>
	<reference anchor="ha_nfs_ibm">		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<front>		FC.1094.xml"/>
	<title>A Highly Available Network Server</title>
	<author initials="A." surname="Bhide" fullname="Anupam Bhide">		<reference anchor="ha_nfs_ibm">
	<organization>IBM T.J. Watson Research Center</organization>		<front>
	</author>		<title>A Highly Available Network Server</title>
	<author initials="E. N." surname="Elnozahy" fullname="Elmootazbellah		<author initials="A." surname="Bhide" fullname="Anupam Bhide">
	N. Elnozahy">		<organization>IBM T.J. Watson Research Center</organization>
	<organization>IBM T.J. Watson Research Center</organization>		</author>
	</author>		<author initials="E. N." surname="Elnozahy" fullname="Elmootazbellah
	<author initials="S. P." surname="Morgan" fullname="Stephen P. Morgan		N. Elnozahy">
	">		<organization>IBM T.J. Watson Research Center</organization>
	<organization>IBM T.J. Watson Research Center</organization>		</author>
	</author>		<author initials="S. P." surname="Morgan" fullname="Stephen P. Morga
	<date month="January" year="1991"/>		n ">
	<abstract>		<organization>IBM T.J. Watson Research Center</organization>
	<t>		</author>
			<date month="January" year="1991"/>
			<abstract>
			<t>
	This paper presents the design and implementation		This paper presents the design and implementation
	of a Highly Available Network File Server		of a Highly Available Network File Server
	(HA-NFS). We separate the problem of network		(HA-NFS). We separate the problem of network
	file server reliability into three different subproblems:		file server reliability into three different subproblems:
	server reliability, disk reliability, and network		server reliability, disk reliability, and network
	reliability. HA-NFS offers a different solution		reliability. HA-NFS offers a different solution
	for each: dual-ported disks and impersonation		for each: dual-ported disks and impersonation
	are used to provide server reliability, disk mirroring		are used to provide server reliability, disk mirroring
	can be used to provide disk reliability, and optional		can be used to provide disk reliability, and optional
	network replication can be used to provide		network replication can be used to provide
	network reliability. The implementation shows		network reliability. The implementation shows
	that HA-NFS provides high availability without		that HA-NFS provides high availability without
	the excessive resource overhead or the performance		the excessive resource overhead or the performance
	degradation that characterize traditional replication		degradation that characterize traditional replication
	methods. Ongoing operations are not aborted		methods. Ongoing operations are not aborted
	during fail-over and recovery is completely transparent		during fail-over and recovery is completely transparent
	to applications. HA-NFS adheres to the		to applications. HA-NFS adheres to the
	NFS protocol standard and can be used by existing		NFS protocol standard and can be used by existing
	NFS clients without modification.		NFS clients without modification.
	</t>		</t>
	</abstract>		</abstract>
	</front>		</front>
	<seriesInfo name="USENIX Conference Proceedings" value="" />		<refcontent>USENIX Conference Proceedings</refcontent>
	</reference>		</reference>
	<reference anchor='RFC5664'>
	<front>
	<title>
	Object-Based Parallel NFS (pNFS) Operations
	</title>
	<author initials='B' surname='Halevy' fullname='Benny Halevy'>
	<organization />
	</author>
	<author initials='B' surname='Welch' fullname='Brent Welch'>
	<organization />
	</author>
	<author initials='J' surname='Zelenka' fullname='Jim Zelenka'>
	<organization />
	</author>
	<date month='January' year='2010' />
	<abstract><t>This Internet-Draft provides a description of the object-based pNFS
	extension for NFSv4. This is a companion to the main pnfs specification in the
	NFSv4 Minor Version 1 Internet Draft, which is currently draft-ietf-nfsv4-minor
	version1-23.</t></abstract>
	</front>
	<seriesInfo name='RFC' value='5664' />
	<format type='TXT'
	target='http://www.ietf.org/internet-drafts/draft-ietf-nfsv4-pnfs-obj-12
	.txt' />
	</reference>
	<reference anchor='RFC5663'>
	<front>
	<title>
	Parallel NFS (pNFS) Block/Volume Layout
	</title>
	<author initials='D' surname='Black' fullname='David Black'>
	<organization />
	</author>
	<author initials='J' surname='Glasgow' fullname='Jason Glasgow'>
	<organization />
	</author>
	<author initials='S' surname='Fridella' fullname='Stephen Fridella'>
	<organization />
	</author>
	<date month='January' year='2010' />
	<abstract><t>Parallel NFS (pNFS) extends NFSv4 to allow clients to
	directly access file data on the storage used by the NFSv4 server.
	This ability to bypass the server for data access can increase both
	performance and parallelism, but requires additional client
	functionality for data access, some of which is dependent on the class
	of storage used. The main pNFS operations draft specifies
	storage-class-independent extensions to NFS; this draft specifies the
	additional extensions (primarily data structures) for use of pNFS with
	block and volume based storage.</t></abstract>
	</front>
	<seriesInfo name='RFC' value='5663' />
	<format type='TXT'
	target='http://www.ietf.org/internet-drafts/draft-ietf-nfsv4-pnfs-block-
	11.txt' />
	</reference>
	<reference anchor='RFC2054'>
	<front>
	<title>WebNFS Client Specification</title>
	<author initials='B.' surname='Callaghan' fullname='Brent Callaghan'>
	<organization>Sun Microsystems, Inc.</organization>
	<address>
	<postal>
	<street>2550 Garcia Avenue</street>
	<street>Mailstop Mpk17-201</street>
	<city>Mountain View</city>
	<region>CA</region>
	<code>94043-1100</code>
	<country>US</country></postal>
	<phone>+1 415 786 5067</phone>
	<facsimile>+1 415 786 5896</facsimile>
	<email>brent.callaghan@eng.sun.com</email></address></author>
	<date year='1996' month='October' />
	<abstract>
	<t>This document describes a lightweight binding mechanism that allows
	NFS clients to obtain service from WebNFS-enabled servers with a
	minimum of protocol overhead. In removing this overhead, WebNFS
	clients see benefits in faster response to requests, easy transit of
	packet filter firewalls and TCP-based proxies, and better server
	scalability.</t></abstract></front>
	<seriesInfo name='RFC' value='2054' />
	<format type='TXT' octets='36354' target='http://www.rfc-editor.org/rfc/rf
	c2054.txt' />
	</reference>
	<reference anchor='RFC2055'>
	<front>
	<title>WebNFS Server Specification</title>
	<author initials='B.' surname='Callaghan' fullname='Brent Callaghan'>
	<organization>Sun Microsystems, Inc.</organization>
	<address>
	<postal>
	<street>2550 Garcia Avenue</street>
	<street>Mailstop Mpk17-201</street>
	<city>Mountain View</city>
	<region>CA</region>
	<code>94043-1100</code>
	<country>US</country></postal>
	<phone>+1 415 786 5067</phone>
	<facsimile>+1 415 786 5896</facsimile>
	<email>brent.callaghan@eng.sun.com</email></address></author>
	<date year='1996' month='October' />
	<abstract>
	<t>This document describes the specifications for a server of WebNFS
	clients. WebNFS extends the semantics of the NFSv3
	protocol to allow clients to obtain filehandles more easily, without
	recourse to the portmap or MOUNT protocols. In removing the need for
	these protocols, WebNFS clients see benefits in faster response to
	requests, easy transit of firewalls and better server scalability Thi
	s
	description is provided to facilitate compatible implementations of
	WebNFS servers.</t></abstract></front>
	<seriesInfo name='RFC' value='2055' />
	<format type='TXT' octets='20498' target='http://www.rfc-editor.org/rfc/rf
	c2055.txt' />
	</reference>
	<reference anchor="errata">
	<front>
	<title>IESG Processing of RFC Errata for the IETF Stream
	</title>
	<author>
	<organization>IESG
	</organization>
	</author>
	<date month="July" year="2008" />
	</front>
	<format type='TXT' target='http://www.ietf.org/IESG/STATEMENTS/iesg-statem
	ent-07-30-2008.txt' />
	</reference>
	<reference anchor='RFC2104'>
	<front>
	<title abbrev='HMAC'>HMAC: Keyed-Hashing for Message Authentication</titl
	e>
	<author initials='H.' surname='Krawczyk' fullname='Hugo Krawczyk'>
	<organization>IBM, T.J. Watson Research Center</organization>
	<address>
	<postal>
	<street>P.O.Box 704</street>
	<city>Yorktown Heights</city>
	<region>NY</region>
	<code>10598</code>
	<country>US</country></postal>
	<email>hugo@watson.ibm.com</email></address></author>
	<author initials='M.' surname='Bellare' fullname='Mihir Bellare'>
	<organization>University of California at San Diego, Dept of Computer S
	cience and Engineering</organization>
	<address>
	<postal>
	<street>9500 Gilman Drive</street>
	<street>Mail Code 0114</street>
	<city>La Jolla</city>
	<region>CA</region>
	<code>92093</code>
	<country>US</country></postal>
	<email>mihir@cs.ucsd.edu</email></address></author>
	<author initials='R.' surname='Canetti' fullname='Ran Canetti'>
	<organization>IBM T.J. Watson Research Center</organization>
	<address>
	<postal>
	<street>P.O.Box 704</street>
	<city>Yorktown Heights</city>
	<region>NY</region>
	<code>10598</code>
	<country>US</country></postal>
	<email>canetti@watson.ibm.com</email></address></author>
	<date year='1997' month='February' />
	<abstract>
	<t>This document describes HMAC, a mechanism for message
	authentication using cryptographic hash functions. HMAC can
	be used with any iterative cryptographic hash function,
	e.g., MD5, SHA-1, in combination with a secret shared key.
	The cryptographic strength of HMAC depends on the properties
	of the underlying hash function.</t></abstract></front>
	<seriesInfo name='RFC' value='2104' />
	<format type='TXT' octets='22297' target='http://www.rfc-editor.org/rfc/rf
	c2104.txt' />
	</reference>
	<reference anchor='RFC2624'>
	<front>
	<title abbrev='NFSv4 Design Considerations'>NFS Version 4 Design Considerations<
	/title>
	<author initials='S.' surname='Shepler' fullname='Spencer Shepler'>
	<organization>Sun Microsystems, Inc.</organization>
	<address>
	<postal>
	<street>7808 Moonflower Drive</street>
	<city>Austin</city>
	<region>TX</region>
	<code>78750</code>
	<country>US</country></postal>
	<phone>+1 512 349 9376</phone>
	<email>spencer.shepler@eng.sun.com</email></address></author>
	<date year='1999' month='June' />
	<abstract>
	<t>The main task of the NFSv4 working group is to create a
	protocol definition for a distributed file system that focuses on the
	following items: improved access and good performance on the Internet,
	strong security with negotiation built into the protocol, better
	cross-platform interoperability, and designed for protocol extensions.
	NFSv4 will owe its general design to the previous versions of
	NFS. It is expected, however, that many features will be quite
	different in NFSv4 than previous versions to facilitate the
	goals of the working group and to address areas that NFSv2 and
	NFSv3 have not.</t>
	<t>This design considerations document is meant to present more detail
	than the working group charter. Specifically, it presents the areas
	that the working group will investigate and consider while developing
	a protocol specification for NFSv4. Based on this
	investigation the working group will decide the features of the new
	protocol based on the cost and benefits within the specific feature
	areas.</t></abstract> <note title='Key Words'>
	<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in RFC
	2119.</t></note></front>
	<seriesInfo name='RFC' value='2624' />		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<format type='TXT' octets='52891' target='http://www.rfc-editor.org/rfc/rfc2624.		FC.5664.xml"/>
	txt' />		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	</reference>		FC.5663.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.2054.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.2055.xml"/>
	<reference anchor="xnfs">		<reference anchor="errata" target="https://www.ietf.org/about/groups/ies
	<front>		g/statements/processing-rfc-errata/">
	<title> Protocols for Interworking: XNFS, Version 3W, ISBN 1-85912-18		<front>
	4-5 </title>		<title>IESG Processing of RFC Errata for the IETF Stream
			</title>
			<author>
			<organization>IESG
			</organization>
			</author>
			<date month="July" year="2008"/>
			</front>
			</reference>
	<author>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<organization>The Open Group </organization>		FC.2104.xml"/>
	</author>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<date month="February" year="1998"/>		FC.2624.xml"/>
	</front>
	</reference>
	<reference anchor="Floyd">		<reference anchor="xnfs">
	<front>		<front>
	<title> The Synchronization of Periodic Routing Messages </title>		<title> Protocols for Interworking: XNFS, Version 3W</title>
			<seriesInfo name="ISBN" value="1-85912-184-5"/>
			<author>
			<organization>The Open Group </organization>
			</author>
			<date month="February" year="1998"/>
			</front>
			</reference>
	<author initials="S." surname="Floyd" >		<reference anchor="Floyd">
	<organization></organization>		<front>
			<title> The Synchronization of Periodic Routing Messages </title>
			<author initials="S." surname="Floyd">
			<organization/>
	</author>		</author>
	<author initials="V." surname="Jacobson">		<author initials="V." surname="Jacobson">
	<organization></organization>		<organization/>
	</author>		</author>
	<date month="April" year="1994"/>		<date month="April" year="1994"/>
	</front>		</front>
			<refcontent>IEEE/ACM Transactions on Networking, 2(2), pp. 122-136</re
	<seriesInfo name="IEEE/ACM Transactions on Networking" value="2(2), pp.		fcontent>
	122-136" />		</reference>
	</reference>
	<reference anchor="RFC3720">		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<front>		FC.7143.xml"/>
	<title>Internet Small Computer Systems Interface (iSCSI)</title>
	<author initials="J." surname="Satran" fullname="J. Satran">
	<organization/>
	</author>
	<author initials="K." surname="Meth" fullname="K. Meth">
	<organization/>
	</author>
	<author initials="C." surname="Sapuntzakis" fullname="C. Sapuntzakis">
	<organization/>
	</author>
	<author initials="M." surname="Chadalapaka" fullname="M. Chadalapaka">
	<organization/>
	</author>
	<author initials="E." surname="Zeidner" fullname="E. Zeidner">
	<organization/>
	</author>
	<date year="2004" month="April"/>
	</front>
	<seriesInfo name="RFC" value="3720"/>
	<format type="TXT" octets="578468" target="http://www.rfc-editor.org/rfc/r
	fc3720.txt"/>
	</reference>
	<reference anchor="FCP-2">		<reference anchor="FCP-2">
	<front>		<front>
	<title>Fibre Channel Protocol for SCSI, 2nd Version (FCP-2)</title>		<title>Fibre Channel Protocol for SCSI, 2nd Version (FCP-2)</title>
	<author initials="R." surname="Snively" fullname="Robert Snively">		<author initials="R." surname="Snively" fullname="Robert Snively">
	<organization>Brocade Communication Systems, Inc.</organization>		<organization>Brocade Communication Systems, Inc.</organization>
	</author>		</author>
	<date month="Oct" year="2003" />		<date month="Oct" year="2003"/>
	</front>		</front>
	<seriesInfo name="ANSI/INCITS" value="350-2003" />		<refcontent>ANSI/INCITS, 350-2003</refcontent>
	</reference>		</reference>
	<reference anchor='OSD-T10'		<reference anchor="OSD-T10" target="https://www.t10.org/drafts.htm">
	target='http://www.t10.org/ftp/t10/drafts/osd/osd-r10.pdf'>		<front>
	<front>		<title>Object-Based Storage Device Commands (OSD)</title>
	<title>Object-Based Storage Device Commands (OSD)</title>		<author initials="R.O." surname="Weber" fullname="Ralph O. Weber">
	<author initials="R.O." surname="Weber" fullname="Ralph O. Weber">		<organization>ENDL Texas</organization>
	<organization>ENDL Texas</organization>		</author>
	</author>		<date month="July" year="2004"/>
	<date month="July" year="2004"/>		</front>
	</front>		<refcontent>ANSI/INCITS, 400-2004</refcontent>
	<seriesInfo name="ANSI/INCITS" value="400-2004"/>		</reference>
	</reference>
	<reference anchor="PVFS">		<reference anchor="PVFS">
	<front>		<front>
	<title>PVFS: A Parallel File System for Linux Clusters.</title>		<title>PVFS: A Parallel File System for Linux Clusters.</title>
			<author initials="P. H." surname="Carns">
	<author initials="P. H." surname="Carns">		<organization> Parallel Architecture Research Laboratory,
	<organization> Parallel Architecture Research Laboratory,
	Clemson University, Clemson, SC 29634 </organization>		Clemson University, Clemson, SC 29634 </organization>
			</author>
	</author>		<author initials="W. B." surname="Ligon III">
	<author initials="W. B." surname="Ligon III">		<organization> Parallel Architecture Research Laboratory,
	<organization> Parallel Architecture Research Laboratory,
	Clemson University, Clemson, SC 29634 </organization>		Clemson University, Clemson, SC 29634 </organization>
	</author>		</author>
			<author initials="R. B." surname="Ross">
	<author initials="R. B." surname="Ross">		<organization> Parallel Architecture Research Laboratory,
	<organization> Parallel Architecture Research Laboratory,
	Clemson University, Clemson, SC 29634 </organization>		Clemson University, Clemson, SC 29634 </organization>
	</author>		</author>
			<author initials="R." surname="Thakur">
	<author initials="R." surname="Thakur">		<organization>Mathematics and Computer Science Division,
	<organization>Mathematics and Computer Science Division,
	Argonne National Laboratory, Argonne, IL 60439</organization>		Argonne National Laboratory, Argonne, IL 60439</organization>
	</author>		</author>
			<date year="2000"/>
	<date year="2000"/>		</front>
	</front>		<refcontent>Proceedings of the 4th Annual Linux Showcase and Conferenc
	<seriesInfo name="Proceedings of the 4th Annual Linux Showcase and Confe		e</refcontent>
	rence" value=""/>		</reference>
	</reference>
	<reference anchor="access_api">		<reference anchor="access_api" target="https://www.opengroup.org">
	<front>		<front>
	<title>The Open Group Base Specifications Issue 6, IEEE Std 1003.1, 2004 Ed		<title>The Open Group Base Specifications Issue 6, IEEE Std 1003.1,
	ition		2004 Edition
	</title>		</title>
	<author>		<author>
	<organization>The Open Group		<organization>The Open Group
	</organization>		</organization>
	</author>		</author>
	<date year="2004" />		<date year="2004"/>
	<abstract>		<abstract>
	<t>		<t>
	The description of the access() function states: "If the process has a ppropriate privileges, an implementation may indicate success for X_OK even if n one of the execute file permission bits are set."		The description of the access() function states: "If the process has a ppropriate privileges, an implementation may indicate success for X_OK even if n one of the execute file permission bits are set."
	</t>		</t>
	</abstract>		</abstract>
			</front>
	</front>		</reference>
	</reference>
	<reference anchor='RFC2224'>
	<front>
	<title>NFS URL Scheme</title>
	<author initials='B.' surname='Callaghan' fullname='Brent Callaghan'>
	<organization>Sun Microsystems, Inc.</organization>
	<address>
	<postal>
	<street>Mailstop Mpk17-201</street>
	<street>901 San Antonio Road</street>
	<street>Palo Alto</street>
	<street>California 94303</street></postal>
	<phone>1-415-786-5067</phone>
	<facsimile>1-415-786-5896</facsimile>
	<email>brent.callaghan@eng.sun.com</email></address></author>
	<date year='1997' month='October' />
	<area>Applications</area>
	<keyword>NFS</keyword>
	<keyword>network file system</keyword>
	<keyword>uniform resource</keyword>
	<abstract>
	<t>
	A new URL scheme, &apos;nfs&apos; is defined. It is used to refer to files a
	nd
	directories on NFS servers using the general URL syntax defined in
	RFC 1738, &quot;Uniform Resource Locators (URL)&quot;.
	</t>
	<t>
	This scheme uses the public filehandle and multi-component look up
	[RFC2054, RFC2055] to access server data with a minimum of protocol
	overhead.
	</t>
	<t>
	The NFS protocol provides access to shared file systems across
	networks. It is designed to be machine, operating system, network
	architecture, and transport protocol independent.
	</t></abstract></front>
	<seriesInfo name='RFC' value='2224' />
	<format type='TXT' octets='22726' target='http://www.rfc-editor.org/rfc/rfc2224.
	txt' />
	<format type='HTML' octets='35259' target='http://xml.resource.org/public/rfc/ht
	ml/rfc2224.html' />
	<format type='XML' octets='24805' target='http://xml.resource.org/public/rfc/xml
	/rfc2224.xml' />
	</reference>
	<reference anchor='RFC2755'>
	<front>
	<title>Security Negotiation for WebNFS</title>
	<author initials='A.' surname='Chiu' fullname='Alex Chiu'>
	<organization>Sun Microsystems, Inc.</organization>
	<address>
	<postal>
	<street>901 San Antonio Road</street>
	<city>Palo Alto</city>
	<region>CA</region>
	<code>94303</code>
	<country>US</country></postal>
	<phone>+1 650 786 6465</phone>
	<email>alex.chiu@Eng.sun.com</email></address></author>
	<author initials='M.' surname='Eisler' fullname='Mike Eisler'>
	<organization>Sun Microsystems, Inc.</organization>
	<address>
	<postal>
	<street>901 San Antonio Road</street>
	<city>Palo Alto</city>
	<region>CA</region>
	<code>94303</code>
	<country>US</country></postal>
	<phone>+1 719 599 9026</phone>
	<email>michael.eisler@Eng.sun.com</email></address></author>
	<author initials='B.' surname='Callaghan' fullname='Brent Callaghan'>
	<organization>Sun Microsystems, Inc.</organization>
	<address>
	<postal>
	<street>901 San Antonio Road</street>
	<city>Palo Alto</city>
	<region>CA</region>
	<code>94303</code>
	<country>US</country></postal>
	<phone>+1 650 786 5067</phone>
	<email>brent.callaghan@Eng.sun.com</email></address></author>
	<date year='2000' month='January' />
	<abstract>
	<t>This document describes a protocol for a WebNFS clientto negotiate the desire
	d security mechanism with a WebNFS serverbefore the WebNFS client falls back to
	the MOUNT v3 protocol. This document is provided so that people can write compat
	ible implementations.</t></abstract></front>
	<seriesInfo name='RFC' value='2755' />
	<format type='TXT' octets='23493' target='http://www.rfc-editor.org/rfc/rfc2755.
	txt' />
	</reference>
	<reference anchor='RFC5226'>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.2224.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.2755.xml"/>
			<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
			FC.8126.xml"/>
	<front>		<reference anchor="Err2006" quote-title="false" target="https://www.rfc-
	<title>Guidelines for Writing an IANA Considerations Section in RFCs</title>		editor.org/errata/eid2006">
	<author initials='T.' surname='Narten' fullname='T. Narten'>		<front>
	<organization /></author>		<title>Erratum ID 2006</title>
	<author initials='H.' surname='Alvestrand' fullname='H. Alvestrand'>		<author>
	<organization /></author>		<organization>RFC Errata</organization>
	<date year='2008' month='May' />		</author>
	<abstract>		</front>
	<t>Many protocols make use of identifiers consisting of constants and other w		<refcontent>RFC 5661</refcontent>
	ell-known values. Even after a protocol has been defined and deployment has begu		</reference>
	n, new values may need to be assigned (e.g., for a new option type in DHCP, or a
	new encryption or authentication transform for IPsec). To ensure that such quan
	tities have consistent values and interpretations across all implementations, th
	eir assignment must be administered by a central authority. For IETF protocols,
	that role is provided by the Internet Assigned Numbers Authority (IANA).&lt;/t>&
	lt;t> In order for IANA to manage a given namespace prudently, it needs guidelin
	es describing the conditions under which new values can be assigned or when modi
	fications to existing values can be made. If IANA is expected to play a role in
	the management of a namespace, IANA must be given clear and concise instructions
	describing that role. This document discusses issues that should be considered
	in formulating a policy for assigning values to a namespace and provides guideli
	nes for authors on the specific text that must be included in documents that pla
	ce demands on IANA.&lt;/t>&lt;t> This document obsoletes RFC 2434. This document
	specifies an Internet Best Current Practices for the Internet Community, and re
	quests discussion and suggestions for improvements.</t></abstract></front>
	<seriesInfo name='BCP' value='26' />		<reference anchor="AFS">
	<seriesInfo name='RFC' value='5226' />		<front>
	<format type='TXT' octets='66160' target='http://www.rfc-editor.org/rfc/rfc52		<title>
	26.txt' />
	</reference>
	<reference anchor="Err2006"
	target="https://www.rfc-editor.org/errata_search.php?eid=2006">
	<front>
	<title>Errata 2006 for RFC 5661</title>
	<author initials='M.' surname='Eisler' fullname='Mike Eisler'>
	</author>
	<date year='2010' month='January' />
	</front>
	</reference>
	<reference anchor="AFS"
	target="https://www.cs.cmu.edu/~satya/docdir/spasojevic-tocs-afs-m
	easurement-1996.pdf">
	<front>
	<title>
	An Empirical Study of a Wide-Area Distributed File System		An Empirical Study of a Wide-Area Distributed File System
	</title>		</title>
	<author initials='M.' surname='Spasojevic' fullname='Mirjana Spasojevic'>		<author initials="M." surname="Spasojevic" fullname="Mirjana Spasoje
			vic">
	</author>		</author>
	<author initials='M.' surname='Satayanarayanan' fullname='Mahadev Satayan arayanan'>		<author initials="M." surname="Satayanarayanan" fullname="Mahadev Sa tayanarayanan">
	</author>		</author>
	<date year='1996' month='May' />		<date year="1996" month="May"/>
	</front>		</front>
	</reference>		<refcontent>ACM Transactions on Computer Systems</refcontent>
			<refcontent>Vol. 14</refcontent>
			<refcontent>No. 2</refcontent>
			<refcontent>pp. 200-222</refcontent>
			<seriesInfo name="DOI" value="10.1145/227695.227698"/>
			</reference>
	<?rfc include="reference.RFC.5661.xml"?>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<?rfc include="reference.RFC.8178.xml"?>		FC.5661.xml"/>
	<?rfc include="reference.RFC.7530.xml"?>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<?rfc include="reference.RFC.7931.xml"?>		FC.8178.xml"/>
	<?rfc include="reference.RFC.8434.xml"?>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<?rfc include="reference.RFC.7258.xml"?>		FC.7530.xml"/>
	<?rfc include="reference.RFC.3552.xml"?>		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	</references>		FC.7931.xml"/>
	<!-- $Id: 2009-12-20-TO-rfc5661.xml,v 1.2 2009/12/21 05:59:32 shepler.mre Exp		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	$ -->		FC.8434.xml"/>
	<!-- Copyright (C) The IETF Trust (2007-2008) -->		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	<!-- Copyright (C) The Internet Society (2006) -->		FC.7258.xml"/>
	<section anchor="NEED"		<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
	title="Need for this Update">		FC.3552.xml"/>
	<t>		</references>
	This document includes an explanation of how clients and		</references>
	servers are to determine		<section anchor="NEED" numbered="true" toc="default">
	the particular network access paths to be used to access a		<name>The Need for This Update</name>
	file system. This includes describing		<t>
	how changes to the specific replica to be used or to		This document includes an explanation of how clients and servers
	the set of addresses to be used to access it are to be		are to determine the particular network access paths to be used to access
	dealt with, and how transfers of responsibility that need to be		a
	made can be dealt with transparently. This includes cases in which		file system. This includes descriptions of
			how to handle changes to the specific replica to be used or to
			the set of addresses to be used to access it,
			and how to deal transparently with transfers of responsibility that need t
			o be
			made. This includes cases in which
	there is a shift between one replica and another and those in		there is a shift between one replica and another and those in
	which different network access paths are used to access the		which different network access paths are used to access the
	same replica.		same replica.
	</t>		</t>
	<t>
	As a result of the following problems in RFC5661
	<xref target="RFC5661"/>, it
	is necessary to provide the specific updates which are made by this
	document. These updates are described in <xref target="CHG"/>
	<list style="symbols">
	<t>		<t>
	RFC5661 <xref target="RFC5661"/>, while it dealt with situations in		As a result of the following problems in RFC 5661
	which various forms of clustering allowed co-ordination		<xref target="RFC5661" format="default"/>, it
	of the state assigned by co-operating servers to be used,		was necessary to provide the specific updates that are made by this
			document. These updates are described in <xref target="CHG" format="defaul
			t"/>.
			</t>
			<ul spacing="normal">
			<li>
			RFC 5661 <xref target="RFC5661" format="default"/>, while it dealt with s
			ituations in
			which various forms of clustering allowed coordination
			of the state assigned by cooperating servers to be used,
	made no provisions for Transparent State Migration. Within NFSv4.0,		made no provisions for Transparent State Migration. Within NFSv4.0,
	Transparent Migration was first explained clearly in		Transparent State Migration was first explained clearly in
	RFC7530 <xref target="RFC7530"/> and corrected and		RFC 7530 <xref target="RFC7530" format="default"/> and corrected and
	clarified by RFC7931 <xref target="RFC7931"/>. No corresponding		clarified by RFC 7931 <xref target="RFC7931" format="default"/>. No corr
			esponding
	explanation for NFSv4.1 had been provided.		explanation for NFSv4.1 had been provided.
	</t>		</li>
	<t>		<li>
	Although NFSv4.1 was defined with a clear definition of how		Although NFSv4.1 provided a clear definition of how
	trunking detection was to be done, there was no clear specification		trunking detection was to be done, there was no clear specification
	of how trunking discovery was to be done, despite the fact that		of how trunking discovery was to be done, despite the fact that
	the specification clearly indicated that this information		the specification clearly indicated that this information
	could be made available via the file system location attributes.		could be made available via the file system location attributes.
	</t>		</li>
	<t>		<li>
	Because the existence of multiple network access paths to the same		Because the existence of multiple network access paths to the same
	file system was		file system was dealt with as if there were multiple replicas, issues re
	dealt with as if there were multiple replicas, issues relating to		lating to
	transitions between replicas could never be clearly distinguished		transitions between replicas could never be clearly distinguished
	from trunking-related transitions between the addresses used to		from trunking-related transitions between the addresses used to
	access a particular file system instance.		access a particular file system instance. As a result, in situations i
	As a result, in situations in		n
	which both migration and trunking configuration changes		which both migration and trunking configuration changes
	were involved, neither of these		were involved, neither of these could be clearly dealt with, and the re
	could be clearly dealt with and the relationship between		lationship between
	these two features was not seriously addressed.		these two features was not seriously addressed.
	</t>		</li>
	<t>		<li>
	Because use of two network access paths to the same file system		Because use of two network access paths to the same file system
	instance		instance (i.e., trunking) was often treated as if two replicas were
	(i.e. trunking) was often treated as if two replicas were		involved, it was considered that two replicas were being used simultaneou
	involved, it was considered that		sly.
	two replicas were being used simultaneously. As a		As a result, the treatment of replicas being used simultaneously
	result, the treatment of replicas being used simultaneously		in RFC 5661 <xref target="RFC5661" format="default"/> was not clear, as i
	in RFC5661 <xref target="RFC5661" /> was not clear as it covered the		t covered the
	two distinct cases of a		two distinct cases of a single file system instance being accessed by
	single file system instance being accessed by		two different network access paths and two
	two different network access
	paths and two
	replicas being accessed simultaneously, with the limitations		replicas being accessed simultaneously, with the limitations
	of the latter case not being clearly laid out.		of the latter case not being clearly laid out.
	</t>		</li>
	</list>		</ul>
	</t>
	<t>
	The majority of the consequences of these issues are dealt with
	by presenting in <xref target="NEW11"/> a replacement for
	Section 11 within RFC5661 <xref target="RFC5661"/>. This replacement
	modifies existing sub-sections within that section and adds new
	ones, as described in <xref target="CHG-11"/>. Also, some existing
	sections are deleted. These changes
	were made in order to:
	<list style="symbols">
	<t>		<t>
	Reorganize the description so that the case		The majority of the consequences of these issues are dealt with
	of two network		by presenting in <xref target="NEW11" format="default"/> a replacement
	access paths to		for Section <xref target="RFC5661" sectionFormat="bare" section="11"/>
	the same file system instance		of RFC 5661 <xref target="RFC5661"/>. This replacement
	needs to be distinguished clearly from the case of		modifies existing subsections within that section and adds new
	two different replicas		ones as described in <xref target="CHG-11" format="default"/>. Also, som
	since, in the		e existing
	former case, locking state is shared and there also		sections were deleted. These changes were made in order to do the
	can be sharing of session state.		following:
	</t>		</t>
	<t>		<ul spacing="normal">
			<li>
			Reorganize the description so that the case of two network access paths
			to
			the same file system instance is distinguished clearly from the case of
			two different replicas since, in the former case, locking state is shared
			and there also
			can be sharing of session state.
			</li>
			<li>
	Provide a clear statement regarding the desirability of		Provide a clear statement regarding the desirability of
	transparent transfer of state between replicas		transparent transfer of state between replicas together with a recommend
	together with a recommendation		ation
	that either that or a single-fs grace period be provided.		that either transparent transfer or a single-fs grace period be provided
	</t>		.
	<t>		</li>
	Specifically delineate how such transfers are to be dealt		<li>
	with by		Specifically delineate how a client is to handle such transfers,
	the client, taking into account the differences from the treatment		taking into account the differences from the treatment
	in <xref target="RFC7931"/> made necessary by the major protocol		in <xref target="RFC7931" format="default"/> made necessary by the major
	changes made in NFSv4.1.		protocol
	</t>		changes to NFSv4.1.
	<t>		</li>
	Provide discussion of the relationship between transparent		<li>
			Discuss the relationship between transparent
	state transfer and Parallel NFS (pNFS).		state transfer and Parallel NFS (pNFS).
	</t>		</li>
	<t>		<li>
	Provide clarification of the fs_locations_info attribute		Clarify the fs_locations_info attribute in order to specify
	in order to specify		which portions of the provided information apply to a specific
	which portions of the information provided apply to a specific		network access path and which apply to the replica that the path
	network access path and which to the replica which that path
	is used to access.		is used to access.
	</t>		</li>
	</list>		</ul>
	</t>
	<t>
	In addition, there are also updates to other sections of
	RFC5661 <xref target="RFC5661"/>, where the consequences of the
	incorrect assumptions
	underlying the current treatment of multi-server namespace
	issues also needed to be corrected. These are to be dealt with as
	described in Sections
	<xref target="CHG-ops" format="counter"/> through
	<xref target="CHG-other" format="counter"/>.
	<list style="symbols">
	<t>		<t>
			In addition, other sections of RFC 5661 <xref target="RFC5661" format="def
			ault"/>
			were updated to correct the consequences of the
			incorrect assumptions underlying the treatment of multi-server namespace
			issues. These are described in Appendices <xref target="CHG-ops" format="
			counter"/> through
			<xref target="CHG-other" format="counter"/>.
			</t>
			<ul spacing="normal">
			<li>
	A revised introductory section regarding multi-server namespace		A revised introductory section regarding multi-server namespace
	facilities is provided.		facilities is provided.
	</t>		</li>
	<t>		<li>
	A more realistic treatment of server scope is provided, which		A more realistic treatment of server scope is provided. This treatment
	reflects the more limited co-ordination of locking state		reflects the more limited coordination of locking state
	adopted by servers actually sharing a common server scope.		adopted by servers actually sharing a common server scope.
	</t>		</li>
	<t>		<li>
	Some confusing text regarding changes in server_owner has		Some confusing text regarding changes in server_owner has
	been clarified.		been clarified.
	</t>		</li>
	<t>		<li>
	The description of some existing errors has been modified		The description of some existing errors has been modified
	to more clearly explain certain errors situations to reflect		to more clearly explain certain error situations to reflect
	the existence of trunking and the possible use of fs-specific grace		the existence of trunking and the possible use of fs-specific grace
	periods. For details, see <xref target="CHG-errs"/>.		periods. For details, see <xref target="CHG-errs" format="default"/>.
	</t>		</li>
	<t>		<li>
	New descriptions of certain existing operations are		New descriptions of certain existing operations are
	provided, either because the existing treatment did not		provided, either because the existing treatment did not
	account for situations that would arise in dealing with		account for situations that would arise in dealing with
	transparent state migration, or because some types of reclaim		Transparent State Migration, or because some types of reclaim
	issues were not adequately dealt with in the context of fs-specific		issues were not adequately dealt with in the context of fs-specific
	grace periods. For details, see <xref target="CHG-ops"/>.		grace periods. For details, see <xref target="CHG-ops" format="default"/>
	</t>		.
	</list>		</li>
	</t>		</ul>
	</section>		</section>
			<section anchor="CHG" numbered="true" toc="default">
	<section anchor="CHG"		<name>Changes in This Update</name>
	title="Changes in this Update">		<section anchor="CHG-11" numbered="true" toc="default">
	<section title="Revisions Made to Section 11 of RFC5661"		<name>Revisions Made to Section 11 of RFC 5661</name>
	anchor="CHG-11">		<t>
	<t>		A number of areas have been revised or extended, in many cases
	A number of areas needed to be revised or extended, in many case		replacing subsections within Section
	replacing existing		<xref target="RFC5661" sectionFormat="bare" section="11"/> of RFC 5661 <xr
	sub-sections		ef target="RFC5661"/>:
	within section 11 of RFC5661 <xref target="RFC5661"/>:		</t>
	<list style="symbols">		<ul spacing="normal">
	<t>		<li>
	New introductory material, including a terminology section,		New introductory material, including a terminology section,
	replaces the existing material		replaces the material in RFC 5661 <xref target="RFC5661" format="default"
	in RFC5661 <xref target="RFC5661"/>		/>,
	ranging from the start of the existing Section 11		ranging from the start of the original Section
	up to and including the existing Section		<xref target="RFC5661" sectionFormat="bare" section="11"/> up to and inc
	11.1. The new material starts at the beginning of		luding
	<xref target="NEW11"/> and continues		Section <xref target="RFC5661" sectionFormat="bare" section="11.1"/>.
	through <xref target="SEC11-loc-attr" format="counter"/>		The new material starts at the beginning of
	below.		<xref target="NEW11" format="default"/> and continues
	</t>		through <xref target="SEC11-loc-attr" format="counter"/>.
	<t>		</li>
	A significant reorganization of the material in the		<li>
	existing Sections 11.4 and 11.5 (of RFC5661		<t>
	<xref target="RFC5661"/>)		A significant reorganization of the material in Sections
	is necessary.		<xref target="RFC5661" sectionFormat="bare" section="11.4"/> and
	The reasons for the reorganization of		<xref target="RFC5661" sectionFormat="bare" section="11.5"/> of RFC 5661
			<xref target="RFC5661"/> was necessary. The reasons for the reorganizati
			on of
	these sections into a single section with multiple subsections		these sections into a single section with multiple subsections
	are discussed in		are discussed in <xref target="SEC11-uses-reorg" format="default"/> belo
	<xref target="SEC11-uses-reorg"/> below.		w.
	This replacement appears as <xref target="SEC11-USES"/>		This replacement appears as <xref target="SEC11-USES" format="default"/>.
	below.		</t>
	<vspace blankLines='1' />		<t>
	New material relating to the handling of the file system location		New material relating to the handling of the file system location
	attributes is contained		attributes is contained in Sections <xref target="SEC11-USES-mult" forma
	in Sections <xref target="SEC11-USES-mult" format="counter"/> and		t="counter"/> and
	<xref target="SEC11-USES-changes" format="counter"/> below.		<xref target="SEC11-USES-changes" format="counter"/>.
	</t>		</t>
	<t>		</li>
			<li>
	A new section describing requirements for user and group		A new section describing requirements for user and group
	handling within a multi-server namespace has been added as		handling within a multi-server namespace has been added as
	<xref target="SEC11-users"/>		<xref target="SEC11-users" format="default"/>.
	</t>		</li>
	<t>		<li>
	A major replacement for the existing Section 11.7 of		A major replacement for Section
	RFC5661 <xref target="RFC5661" /> entitled		<xref target="RFC5661" sectionFormat="bare" section="11.7"/> of RFC 5661
	"Effecting File System Transitions", will appear as Sections		<xref target="RFC5661"/>,
	<xref target="SEC11-trans-oview" format="counter"/>		entitled "Effecting File System Transitions", appears as Sections
	through <xref target="SEC11-trans-server" format="counter"/>.		<xref target="SEC11-trans-oview" format="counter"/> through
			<xref target="SEC11-trans-server" format="counter"/>.
	The reasons for the reorganization of		The reasons for the reorganization of
	this section into multiple sections are discussed in		this section into multiple sections are discussed in
	<xref target="SEC11-trans-reorg"/>.		<xref target="SEC11-trans-reorg" format="default"/>.
	</t>		</li>
	<t>		<li>
	A replacement for the existing Section 11.10 of		A replacement for Section
	RFC5661 <xref target="RFC5661" /> entitled		<xref target="RFC5661" sectionFormat="bare" section="11.10"/> of RFC 566
	"The Attribute fs_locations_info", will appear as		1 <xref target="RFC5661"/>,
	<xref target="SEC11-li-new"/>, with		entitled "The Attribute fs_locations_info", appears as
	<xref target="SEC11-li-changes"/> describing the differences		<xref target="SEC11-li-new" format="default"/>, with
			<xref target="SEC11-li-changes" format="default"/> describing the differe
			nces
	between the new section and the treatment within		between the new section and the treatment within
	<xref target="RFC5661" />.		<xref target="RFC5661" format="default"/>.
	A revised treatment is necessary because the existing treatment		A revised treatment was necessary because the original treatment
	did not make clear how the added attribute information relates		did not make clear how the added attribute information relates
	to the case of trunked paths to the same replica. These issues		to the case of trunked paths to the same replica. These issues
	were not addressed in RFC5661 <xref target="RFC5661" /> where the		were not addressed in RFC 5661 <xref target="RFC5661" format="default"/> where the
	concepts of a replica and a network path used to access a replica		concepts of a replica and a network path used to access a replica
	were not clearly distinguished.		were not clearly distinguished.
	</t>		</li>
	</list>		</ul>
			<section anchor="SEC11-uses-reorg" toc="exclude" numbered="true">
	</t>		<name>Reorganization of Sections 11.4 and 11.5 of RFC 5661</name>
			<t>
	<section title="Re-organization of Sections 11.4 and 11.5 of RFC5661"
	anchor="SEC11-uses-reorg"
	toc="exclude">
	<t>
	Previously, issues related to the fact that multiple location		Previously, issues related to the fact that multiple location
	entries directed the client to the same file system instance		entries directed the client to the same file system instance
	were dealt with		were dealt with in Section <xref target="RFC5661" sectionFormat="bare" se
	in a separate Section 11.5 of RFC5661 <xref target="RFC5661"/>.		ction="11.5"/> of RFC 5661 <xref target="RFC5661"/>.
	Because of the new treatment of		Because of the new treatment of trunking, these issues now belong
	trunking, these issues now belong within <xref target="SEC11-USES"/>		within <xref target="SEC11-USES" format="default"/>.
	below.		</t>
	</t>		<t>
	<t>		In this new section, trunking is covered in
	In this new section,		<xref target="SEC11-USES-trunk" format="default"/> together with the oth
	trunking is dealt with in		er uses
	<xref target="SEC11-USES-trunk"/> together with the other uses
	of file system location information described in Sections		of file system location information described in Sections
	<xref target="SEC11-USES-types"/> through		<xref target="SEC11-USES-types" format="counter"/> through
	<xref target="SEC11-USES-ref" format="counter"/>.		<xref target="SEC11-USES-ref" format="counter"/>.
	</t>		</t>
	<t>		<t>
	As a result, <xref target="SEC11-USES"/> which will replace		As a result, <xref target="SEC11-USES" format="default"/>, which replaces
	Section 11.4 of RFC5661 <xref target="RFC5661"/> is substantially		Section <xref target="RFC5661" sectionFormat="bare" section="11.4"/>
	different than the section it replaces in that some existing		of RFC 5661 <xref target="RFC5661"/>, is substantially
	sections will be replaced by corresponding sections below while,		different than the section it replaces in that some original
	at the same time, new sections will be added, resulting in		sections have been replaced by corresponding sections as described below,
	a replacement containing some renumbered sections, as follows:		while
	<list style ='symbols'>		new sections have been added:
	<t>		</t>
	The material in <xref target="SEC11-USES"/>,		<ul spacing="normal">
			<li>
			The material in <xref target="SEC11-USES" format="default"/>,
	exclusive of subsections, replaces the material		exclusive of subsections, replaces the material
	in Section 11.4 of RFC5661 <xref target="RFC5661"/> exclusive of		in Section <xref target="RFC5661" sectionFormat="bare" section="11.4"/> of RFC 5661 <xref target="RFC5661"/> exclusive of
	subsections.		subsections.
	</t>		</li>
	<t>		<li>
	<xref target="SEC11-USES-mult"/>		<xref target="SEC11-USES-mult" format="default"/>
	is a new first subsection of the overall section.		is the new first subsection of the overall section.
			</li>
	</t>		<li>
	<t>		<xref target="SEC11-USES-trunk" format="default"/>
	<xref target="SEC11-USES-trunk"/>		is the new second subsection of the overall section.
	is a new second subsection of the overall section.		</li>
	</t>		<li>
	<t>
	Each of the Sections		Each of the Sections
	<xref target="SEC11-USES-repl" format="counter"/>,		<xref target="SEC11-USES-repl" format="counter"/>,
	<xref target="SEC11-USES-migr" format="counter"/>, and		<xref target="SEC11-USES-migr" format="counter"/>, and
	<xref target="SEC11-USES-ref" format="counter"/>		<xref target="SEC11-USES-ref" format="counter"/>
	replaces (in order) one of		replaces (in order) one of the corresponding Sections
	the corresponding		<xref target="RFC5661" sectionFormat="bare" section="11.4.1"/>,
	Sections 11.4.1, 11.4.2, and 11.4.3 of		<xref target="RFC5661" sectionFormat="bare" section="11.4.2"/>, and
	RFC5661 <xref target="RFC5661"/>.		<xref target="RFC5661" sectionFormat="bare" section="11.4.3"/> of RFC
	11.4.4, and 11.4.5.		5661
	</t>		<xref target="RFC5661"/>.
	<t>		</li>
	<xref target="SEC11-USES-changes"/>		<li>
	is a new final subsection of the overall section.		<xref target="SEC11-USES-changes" format="default"/>
	</t>		is the new final subsection of the overall section.
	</list>		</li>
	</t>		</ul>
	</section>		</section>
	<section title="Re-organization of Material Dealing with File System Transit		<section anchor="SEC11-trans-reorg" toc="exclude" numbered="true">
	ions"		<name>Reorganization of Material Dealing with File System Transitions<
	anchor="SEC11-trans-reorg"		/name>
	toc="exclude">		<t>
	<t>
	The material relating to file system transition, previously contained		The material relating to file system transition, previously contained
	in Section 11.7 of RFC5661 <xref target="RFC5661"/> has		in Section <xref target="RFC5661" sectionFormat="bare" section="11.7"/> o f RFC 5661 <xref target="RFC5661"/> has
	been reorganized and augmented as described below:		been reorganized and augmented as described below:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	Because there can be a shift of the network access paths used to		Because there can be a shift of the network access paths used to
	access a file system instance without any shift between replicas,		access a file system instance without any shift between replicas,
	a new <xref target="SEC11-trans-oview"/> distinguishes		a new <xref target="SEC11-trans-oview" format="default"/> distinguishes
	between those cases in which there is a shift between		between those cases in which there is a shift between
	distinct replicas and those involving a shift in network		distinct replicas and those involving a shift in network
	access paths		access paths with no shift between replicas.
	with no shift between replicas.		</t>
	<vspace blankLines="1"/>		<t>
	As a result, a new <xref target="SEC11-nwa"/> deals with network		As a result, the new <xref target="SEC11-nwa" format="default"/> deals
	address transitions while the bulk of the former Section 11.7		with network
	(in RFC5661 <xref target="RFC5661"/>)		address transitions, while the bulk of the original Section
	is extensively modified as reflected in		<xref target="RFC5661" sectionFormat="bare" section="11.7"/> of RFC
	<xref target="SEC11-EFF"/>		5661 <xref target="RFC5661"/> has been extensively modified as reflecte
	which is now limited to cases		d in
			<xref target="SEC11-EFF" format="default"/>, which is now limited to ca
			ses
	in which there is a shift between two different sets of replicas.		in which there is a shift between two different sets of replicas.
			</t>
	</t>		</li>
	<t>		<li>
	The additional <xref target="SEC11-trans-locking"/> discusses the		The additional <xref target="SEC11-trans-locking" format="default"/> di
			scusses the
	case in which a shift to a different replica is made and state		case in which a shift to a different replica is made and state
	is transferred to allow the client the ability to have continued		is transferred to allow the client the ability to have continued
	access to its accumulated locking state on the new server.		access to its accumulated locking state on the new server.
	</t>		</li>
	<t>		<li>
	The additional <xref target="SEC11-trans-client"/> discusses		The additional <xref target="SEC11-trans-client" format="default"/> dis
	the client's response to access transitions and how it determines		cusses
			the client's response to access transitions, how it determines
	whether migration has occurred, and how it gets access to any		whether migration has occurred, and how it gets access to any
	transferred		transferred locking and session state.
	locking and session state.		</li>
	</t>		<li>
	<t>		The additional <xref target="SEC11-trans-server" format="default"/> dis
	The additional <xref target="SEC11-trans-server"/> discusses the		cusses the
	responsibilities of the source and destination servers when		responsibilities of the source and destination servers when
	transferring locking and session state.		transferring locking and session state.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		This reorganization has caused a renumbering of the sections
	This re-organization has caused a renumbering of the sections		within <xref target="RFC5661" sectionFormat="of" section="11"/> as descri
	within Section 11 of <xref target="RFC5661"/> as described below:		bed below:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
	The new Sections <xref target="SEC11-trans-oview" format="counter"/>		The new Sections <xref target="SEC11-trans-oview" format="counter"/>
	and <xref target="SEC11-nwa" format="counter"/> have resulted		and <xref target="SEC11-nwa" format="counter"/> have resulted
	in existing sections with these numbers to be renumbered.		in the renumbering of existing sections with these numbers.
	</t>		</li>
	<t>		<li>
	Section 11.7 of <xref target="RFC5661"/> will be substantially		<xref target="RFC5661" sectionFormat="of" section="11.7"/> has been sub
	modified and appear as		stantially
	<xref target="SEC11-EFF"/>. The necessary		modified and appears as <xref target="SEC11-EFF" format="default"/>.
	modifications reflect the fact that this section will only deal		The necessary
	with transitions between replicas while transitions between		modifications reflect the fact that this section only deals
			with transitions between replicas, while transitions between
	network addresses are dealt with in other sections. Details		network addresses are dealt with in other sections. Details
	of the reorganization are described later in this section.		of the reorganization are described later in this section.
	</t>		</li>
	<t>		<li>
	The additional Sections		Sections
	<xref target="SEC11-trans-locking" format="counter"/>,		<xref target="SEC11-trans-locking" format="counter"/>,
	<xref target="SEC11-trans-client" format="counter"/>, and		<xref target="SEC11-trans-client" format="counter"/>, and
	<xref target="SEC11-trans-server" format="counter"/> have been		<xref target="SEC11-trans-server" format="counter"/> have been
	added.		added.
	</t>		</li>
	<t>		<li>
	Consequently, Sections 11.8, 11.9, 11.10, and 11.11 in		Consequently, Sections <xref target="RFC5661" sectionFormat="bare" sect
	<xref target="RFC5661"/> now appear		ion="11.8"/>,
	as Sections 11.13, 11.14, 11.15, and 11.16,		<xref target="RFC5661" sectionFormat="bare" section="11.9"/>,
			<xref target="RFC5661" sectionFormat="bare" section="11.10"/>, and
			<xref target="RFC5661" sectionFormat="bare" section="11.11"/> in
			<xref target="RFC5661" format="default"/> now appear
			as Sections <xref target="effecting_referrals" format="counter"/>,
			<xref target="fs_locations" format="counter"/>,
			<xref target="SEC11-li-new" format="counter"/>, and
			<xref target="fs_status" format="counter"/>,
	respectively.		respectively.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		As part of this general reorganization,
	As part of this general re-organization, Section 11.7 of		Section <xref target="RFC5661" sectionFormat="bare" section="11.7"/> of
	RFC5661 <xref target="RFC5661"/> will be modified as described below:		RFC 5661 <xref target="RFC5661"/>
	<list style="symbols">		has been modified as described below:
	<t>		</t>
	Sections 11.7 and 11.7.1 of RFC5661 <xref target="RFC5661"/>		<ul spacing="normal">
	are to be		<li>
	replaced by Sections <xref target="SEC11-EFF" format="counter"/>		Sections <xref target="RFC5661" sectionFormat="bare" section="11.7"/> a
	and <xref target="SEC11-EFF-simul" format="counter"/>, respectively.		nd
	</t>		<xref target="RFC5661" sectionFormat="bare" section="11.7.1"/> of RFC
	<t>		5661 <xref target="RFC5661" format="default"/>
	Section 11.7.2 (and included subsections)		have been replaced by Sections
	of RFC5661 <xref target="RFC5661"/> are to be deleted.		<xref target="SEC11-EFF" format="counter"/> and
	</t>		<xref target="SEC11-EFF-simul" format="counter"/>, respectively.
	<t>		</li>
	Sections 11.7.3, 11.7.4. 11.7.5, 11.7.5.1, and 11.7.6		<li>
	of RFC5661 <xref target="RFC5661"/> are to be replaced by Sections		Section <xref target="RFC5661" sectionFormat="bare" section="11.7.2"/>
			of RFC 5661 (and included subsections) has been deleted.
			</li>
			<li>
			Sections <xref target="RFC5661" sectionFormat="bare" section="11.7.3"/>
			,
			<xref target="RFC5661" sectionFormat="bare" section="11.7.4"/>,
			<xref target="RFC5661" sectionFormat="bare" section="11.7.5"/>,
			<xref target="RFC5661" sectionFormat="bare" section="11.7.5.1"/>, and
			<xref target="RFC5661" sectionFormat="bare" section="11.7.6"/> of RFC
			5661
			<xref target="RFC5661" format="default"/> have been replaced by Sectio
			ns
	<xref target="SEC11-EFF-fh" format="counter"/>,		<xref target="SEC11-EFF-fh" format="counter"/>,
	<xref target="SEC11-EFF-fileid" format="counter"/>,		<xref target="SEC11-EFF-fileid" format="counter"/>,
	<xref target="SEC11-EFF-fsid" format="counter"/>,		<xref target="SEC11-EFF-fsid" format="counter"/>,
	<xref target="SEC11-EFF-fsid-split" format="counter"/>, and		<xref target="SEC11-EFF-fsid-split" format="counter"/>, and
	<xref target="SEC11-EFF-change" format="counter"/>		<xref target="SEC11-EFF-change" format="counter"/>
	respectively in this document.		respectively in this document.
	</t>		</li>
	<t>		<li>
	Section 11.7.7 of RFC5661 <xref target="RFC5661"/>		Section <xref target="RFC5661" sectionFormat="bare" section="11.7.7"/>
	is to be replaced by		of RFC 5661 <xref target="RFC5661"/> has been replaced by
	<xref target="SEC11-EFF-lock"/> This sub-section has been		<xref target="SEC11-EFF-lock" format="default"/>. This subsection has
	moved to the end of the section dealing with file system		been
	transitions.		moved to the end of the section dealing with file system transitions.
	</t>		</li>
	<t>		<li>
	Sections 11.7.8, 11.7.9. and 11.7.10 of		Sections <xref target="RFC5661" sectionFormat="bare" section="11.7.8"/>
	RFC5661 <xref target="RFC5661"/> are to be replaced by Sections		,
			<xref target="RFC5661" sectionFormat="bare" section="11.7.9"/>, and
			<xref target="RFC5661" sectionFormat="bare" section="11.7.10"/> of RFC
			5661
			<xref target="RFC5661" format="default"/> have been replaced by Sectio
			ns
	<xref target="SEC11-EFF-wv" format="counter"/>,		<xref target="SEC11-EFF-wv" format="counter"/>,
	<xref target="SEC11-EFF-rdc" format="counter"/>, and		<xref target="SEC11-EFF-rdc" format="counter"/>, and
	<xref target="SEC11-EFF-data" format="counter"/>		<xref target="SEC11-EFF-data" format="counter"/>
	respectively in this document.		respectively in this document.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section anchor="SEC11-li-changes" toc="exclude" numbered="true">
	<section title="Updates to treatment of fs_locations_info"		<name>Updates to the Treatment of fs_locations_info</name>
	anchor="SEC11-li-changes"		<t>
	toc="exclude">
	<t>
	Various elements of the fs_locations_info attribute contain		Various elements of the fs_locations_info attribute contain
	information that applies to either a specific file system replica		information that applies to either a specific file system replica
	or to a network path or set of network paths used to access such		or to a network path or set of network paths used to access such a replic
	a replica.		a.
	The existing treatment of fs_locations info (in Section 11.10 of		The original treatment of fs_locations_info (Section <xref target="RFC566
	RFC5661 <xref target="RFC5661"/>) does not clearly		1" sectionFormat="bare" section="11.10"/> of RFC 5661 <xref target="RFC5661"/>)
	distinguish these cases, in		did not clearly distinguish these cases, in
	part because the document did not clearly distinguish replicas from		part because the document did not clearly distinguish replicas from
	the paths used to access them.		the paths used to access them.
	</t>		</t>
	<t>		<t>
	In addition, special clarification needed to be provided with regard		In addition, special clarification has been provided with regard
	to the following fields:		to the following fields:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	With regard to the handling of FSLI4GF_GOING, it needs to be		<li>
	made clear that this only applies to the unavailability of a		With regard to the handling of FSLI4GF_GOING, it was
			clarified that this only applies to the unavailability of a
	replica rather than to a path to access a replica.		replica rather than to a path to access a replica.
	</t>		</li>
	<t>		<li>
	In describing the appropriate value for a server to use for		In describing the appropriate value for a server to use for
	fli_valid_for, it needs to be made clear that there is no		fli_valid_for, it was clarified that there is no
	need for the client to frequently fetch the fs_locations_info		need for the client to frequently fetch the fs_locations_info
	value to be prepared for shifts in trunking patterns.		value to be prepared for shifts in trunking patterns.
	</t>		</li>
	<t>		<li>
	Clarification of the rules for extensions to the fls_info needs		Clarification of the rules for extensions to the fls_info has
	to be provided. The existing treatment reflects the extension		been provided. The original treatment reflected the extension
	model in effect at the time RFC5661 <xref target="RFC5661"/>		model that was in effect at the time RFC 5661 <xref target="RFC5661" fo
	was written,		rmat="default"/>
	and needed to be updated in accordance with the extension model		was written, but has been updated in accordance with the extension mode
	described in RFC8178 <xref target="RFC8178"/>.		l
	</t>		described in RFC 8178 <xref target="RFC8178" format="default"/>.
	</list>		</li>
	</t>		</ul>
	</section>		</section>
	</section>		</section>
	<section title="Revisions Made to Operations in RFC5661"		<section anchor="CHG-ops" numbered="true" toc="default">
	anchor="CHG-ops">		<name>Revisions Made to Operations in RFC 5661</name>
	<t>		<t>
	Revised descriptions were needed to address issues that arose in		Descriptions have been revised to address issues that arose in
	effecting necessary changes to multi-server namespace features.		effecting necessary changes to multi-server namespace features.
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	The existing treatment of EXCHANGE_ID (in Section 18.35 of		<li>
	RFC5661 <xref target="RFC5661"/>) assumes that client IDs		The treatment of EXCHANGE_ID (Section <xref target="RFC5661" sectionForm
	cannot be created/		at="bare" section="18.35"/> of RFC 5661 <xref target="RFC5661"/>) assumed that c
	confirmed other than by the EXCHANGE_ID and CREATE_SESSION		lient IDs
			cannot be created/confirmed other than by the EXCHANGE_ID and CREATE_SESS
			ION
	operations. Also, the necessary use of EXCHANGE_ID in recovery		operations. Also, the necessary use of EXCHANGE_ID in recovery
	from migration and related situations is not addressed clearly.		from migration and related situations was not clearly addressed.
	A revised treatment of EXCHANGE_ID is necessary and it appears in		A revised treatment of EXCHANGE_ID was necessary, and it appears in
	<xref target="OP_EXCHANGE_ID"/> while the specific differences		<xref target="OP_EXCHANGE_ID" format="default"/>, while the specific dif
	between it and the treatment within <xref target="RFC5661"/>		ferences
	are explained in <xref target="OTH-eid"/> below.		between it and the treatment within <xref target="RFC5661" format="defaul
	</t>		t"/>
	<t>		are explained in <xref target="OTH-eid" format="default"/> below.
	The existing treatment of RECLAIM_COMPLETE in section 18.51 of		</li>
	RFC5661 <xref target="RFC5661"/>) is not sufficiently clear about the		<li>
	purpose and use of the rca_one_fs and how the server is to deal		The treatment of RECLAIM_COMPLETE in Section <xref target="RFC5661" secti
			onFormat="bare" section="18.51"/> of RFC 5661 <xref target="RFC5661"/> was not s
			ufficiently clear about the
			purpose and use of the rca_one_fs and how the server was to deal
	with inappropriate values of this argument. Because the		with inappropriate values of this argument. Because the
	resulting confusion raises interoperability issues, a new treatment		resulting confusion raised interoperability issues, a new treatment
	of RECLAIM_COMPLETE is necessary and it appears in		of RECLAIM_COMPLETE was necessary, and it appears in
	<xref target="OP_RECLAIM_COMPLETE"/> below while the specific differences		<xref target="OP_RECLAIM_COMPLETE" format="default"/>, while the specific
	between it and the treatment within RFC5661 <xref target="RFC5661"/>		differences
	are discussed in <xref target="OTH-rc"/> below. In addition, the		between it and the treatment within RFC 5661 <xref target="RFC5661" forma
	definitions of the reclaim-related errors receive an updated		t="default"/>
	treatment in <xref target="errors_reclaim"/> to reflect the fact		are discussed in <xref target="OTH-rc" format="default"/> below. In addi
			tion, the
			definitions of the reclaim-related errors have received an updated
			treatment in <xref target="errors_reclaim" format="default"/> to reflect
			the fact
	that there are multiple contexts for lock reclaim operations.		that there are multiple contexts for lock reclaim operations.
	</t>		</li>
	</list>		</ul>
	</t>		<section anchor="OTH-eid" toc="exclude" numbered="true">
	<section title="Revision to Treatment of EXCHANGE_ID"		<name>Revision of Treatment of EXCHANGE_ID</name>
	anchor="OTH-eid"		<t>
	toc="exclude">		There was a number of issues in the original treatment of
			EXCHANGE_ID in RFC 5661 <xref target="RFC5661" format="default"/> that ca
	<t>		used problems
	There are a number of issues in the original treatment of
	EXCHANGE_ID (in RFC5661 <xref target="RFC5661"/>) that cause problems
	for Transparent State Migration and for the transfer of access		for Transparent State Migration and for the transfer of access
	between different network access paths		between different network access paths to the same file system instance.
	to the same file system instance.		</t>
	</t>		<t>
	<t>		These issues arose from the fact that this treatment was written:
	These issues arise from the fact that this treatment was		</t>
	written,		<ul spacing="normal">
	<list style="symbols">		<li>
	<t>
	Assuming that a client ID can only become known to a server		Assuming that a client ID can only become known to a server
	by having been created by executing an EXCHANGE_ID, with		by having been created by executing an EXCHANGE_ID, with
	confirmation of the ID only possible by execution of a		confirmation of the ID only possible by execution of a
	CREATE_SESSION.		CREATE_SESSION.
	</t>		</li>
	<t>		<li>
	Considering the interactions between a client and a server only		Considering the interactions between a client and a server only
	occurring on a single network address		occurring on a single network address.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>
	As these assumptions have become invalid in the context of		As these assumptions have become invalid in the context of
	Transparent State Migration and active use of trunking,		Transparent State Migration and active use of trunking,
	the treatment has been modified in		the treatment has been modified in several respects:
	several respects.		</t>
	<list style="symbols">		<ul spacing="normal">
	<t>		<li>
	It had been assumed that an		<t>
	EXCHANGED_ID executed when the server is already aware of a		It had been assumed that an EXCHANGE_ID executed when the server
	given client instance must be either updating associated		was already aware that a given client instance was either updating
	parameters (e.g. with respect to callbacks) or a lingering		associated parameters (e.g., with respect to callbacks) or dealing
	retransmission to deal with a previously lost reply. As		with a previously lost reply by retransmitting. As a
	result, any slot sequence returned by that operation		result, any slot sequence returned by that operation
	would be of no use.		would be of no use. The original treatment
	The existing treatment		went so far as to say that it "<bcp14>MUST NOT</bcp14>" be used, altho
	goes so far as to say that it "MUST NOT" be used, although		ugh
	this usage is not in accord with <xref target="RFC2119"/>.		this usage was not in accord with <xref target="RFC2119" format="defau
	This created		lt"/>.
	a difficulty when an EXCHANGE_ID is done after Transparent State		This created a difficulty when an EXCHANGE_ID is done after Transparen
			t State
	Migration since that slot sequence would need to be used in a		Migration since that slot sequence would need to be used in a
	subsequent CREATE_SESSION.		subsequent CREATE_SESSION.
	<vspace blankLines="1"/>		</t>
			<t>
	In the updated treatment, CREATE_SESSION is a way that client		In the updated treatment, CREATE_SESSION is a way that client
	IDs are confirmed but it is understood that other ways are		IDs are confirmed, but it is understood that other ways are
	possible. The slot sequence can be used as needed and cases		possible. The slot sequence can be used as needed, and cases
	in which it would be of no use are appropriately noted.		in which it would be of no use are appropriately noted.
	</t>		</t>
	<t>		</li>
	It was assumed that the only functions of EXCHANGE_ID were to		<li>
	inform the server of the client, create the client ID,		<t>
	and communicate it to the client. When multiple		It had been assumed that the only functions of EXCHANGE_ID were to
			inform the server of the client, to create the client ID,
			and to communicate it to the client. When multiple
	simultaneous connections are involved, as often happens when		simultaneous connections are involved, as often happens when
	trunking, that treatment was inadequate in that it ignored the		trunking, that treatment was inadequate in that it ignored the
	role of EXCHANGE_ID in associating the client ID with the		role of EXCHANGE_ID in associating the client ID with the
	connection on which it was done, so that it could be used		connection on which it was done, so that it could be used
	by a subsequent CREATE_SESSSION, whose parameters do not		by a subsequent CREATE_SESSION whose parameters do not
	include an explicit client ID.		include an explicit client ID.
	<vspace blankLines="1"/>		</t>
			<t>
	The new treatment explicitly discusses the role of EXCHANGE_ID		The new treatment explicitly discusses the role of EXCHANGE_ID
	in associating the client ID with the connection so it		in associating the client ID with the connection so it
	can be used		can be used by CREATE_SESSION and in associating a connection with an
	by CREATE_SESSION and in associating a connection with an
	existing session.		existing session.
	</t>		</t>
			</li>
	</list>		</ul>
	</t>		<t>
	<t>		The new treatment can be found in <xref target="OP_EXCHANGE_ID" format="
	The new treatment can be found in <xref target="OP_EXCHANGE_ID"/>		default"/>
	above.		above. It supersedes the treatment in Section
	It supersedes the treatment in Section 18.35 of		<xref target="RFC5661" sectionFormat="bare" section="18.35"/> of RFC 566
	RFC5661 <xref target="RFC5661"/>.		1 <xref target="RFC5661"/>.
	</t>		</t>
	</section>		</section>
	<section title="Revision to Treatment of RECLAIM_COMPLETE"		<section anchor="OTH-rc" toc="exclude" numbered="true">
	anchor="OTH-rc"		<name>Revision of Treatment of RECLAIM_COMPLETE</name>
	toc="exclude">		<t>
	<t>
	The following changes were made to the treatment of		The following changes were made to the treatment of
	RECLAIM_COMPLETE in RFC5661 <xref target="RFC5661"/> to arrive at the		RECLAIM_COMPLETE in RFC 5661 <xref target="RFC5661" format="default"/> to
	treatment in <xref target="OP_RECLAIM_COMPLETE"/>.		arrive at the
	<list style="symbols">		treatment in <xref target="OP_RECLAIM_COMPLETE" format="default"/>:
	<t>		</t>
	In a number of places the text is made more explicit about the		<ul spacing="normal">
			<li>
			In a number of places, the text was made more explicit about the
	purpose of rca_one_fs and its connection to file system		purpose of rca_one_fs and its connection to file system
	migration.		migration.
	</t>		</li>
	<t>		<li>
	There is a discussion of situations in which particular forms of		There is a discussion of situations in which particular forms of
	RECLAIM_COMPLETE would need to be done.		RECLAIM_COMPLETE would need to be done.
	</t>		</li>
	<t>		<li>
	There is a discussion of interoperability issues that result		There is a discussion of interoperability issues between
	from implementations that may have arisen due to the lack of		implementations that may have arisen due to the lack of
	clarity of the previous treatment of RECLAIM_COMPLETE.		clarity of the previous treatment of RECLAIM_COMPLETE.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="CHG-errs" numbered="true" toc="default">
			<name>Revisions Made to Error Definitions in RFC 5661</name>
	<section title="Revisions Made to Error Definitions in RFC5661"		<t>
	anchor="CHG-errs">		The new handling of various situations required revisions to
	<t>		some existing error definitions:
	The new handling of various situations required revisions of		</t>
	some existing error definition:		<ul spacing="normal">
	<list style="symbols">		<li>
	<t>		<t>
	Because of the need to appropriately address trunking-related		Because of the need to appropriately address trunking-related
	issues, some uses of the term "replica" in RFC5661		issues, some uses of the term "replica" in RFC 5661
	<xref target="RFC5661"/>		<xref target="RFC5661" format="default"/>
	have become problematic since a shift in network access paths was		became problematic because a shift in network access paths was
	considered to be a shift to a different replica. As a result,		considered to be a shift to a different replica. As a result,
	the existing definition of NFS4ERR_MOVED (in Section 15.1.2.4 of		the original definition of NFS4ERR_MOVED (in Section <xref target="RFC56
	RFC5661 <xref target="RFC5661"/>) needs to be updated to reflect the		61" sectionFormat="bare" section="15.1.2.4"/> of RFC 5661 <xref target="RFC5661"
			/>) was updated to reflect the
	different handling of unavailability of a particular fs via a		different handling of unavailability of a particular fs via a
	specific network address.		specific network address.
	<vspace blankLines="1"/>		</t>
			<t>
	Since such a situation is no longer		Since such a situation is no longer
	considered to constitute unavailability of a file system		considered to constitute unavailability of a file system
	instance, the description needs		instance, the description has been changed, even though the set of circu
	to change even though the set of circumstances in		mstances in
	which it is to be returned remain the same.		which it is to be returned remains the same.
	The new paragraph explicitly recognizes that a different network		The new paragraph explicitly recognizes that a different network
	address might be used, while the previous description, misleadingly,		address might be used, while the previous description, misleadingly,
	treated this as a shift between two replicas while only a single		treated this as a shift between two replicas while only a single
	file system instance might be involved.		file system instance might be involved. The updated description
	The updated description		appears in <xref target="err_MOVED" format="default"/>.
	appears in <xref target="err_MOVED"/> below.		</t>
	</t>		</li>
	<t>		<li>
	Because of the need to accommodate use of fs-specific grace periods,		Because of the need to accommodate the use of fs-specific grace periods,
	it is necessary to clarify some of the error definitions of		it was necessary to clarify some of the definitions of
	reclaim-related errors in Section 15 of RFC5661		reclaim-related errors in Section
	<xref target="RFC5661"/>,		<xref target="RFC5661" sectionFormat="bare" section="15"/> of RFC 5661
	so the text applies properly to reclaims for all types of grace		<xref target="RFC5661"/>
	periods.		so that the text applies properly to reclaims for all types of grace
	The updated descriptions		periods. The updated descriptions
	appear within <xref target="errors_reclaim"/> below.		appear within <xref target="errors_reclaim" format="default"/>.
	</t>		</li>
	<t>		<li>
	Because of the need to provide the clarifications in errata		Because of the need to provide the clarifications in errata
	report 2006		report 2006 <xref target="Err2006" format="default"/>
	<xref target="Err2006"/>
	and to adapt these to properly explain the interaction of		and to adapt these to properly explain the interaction of
	NFS4ERR_DELAY with the replay cache, a revised description		NFS4ERR_DELAY with the reply cache, a revised description
	of NFS4ERR_DELAY appears in <xref target="err_DELAY"/>. This		of NFS4ERR_DELAY appears in <xref target="err_DELAY" format="default"/>.
	errata report, unlike many other RFC5661 errata reports, is		This
			errata report, unlike many other RFC 5661 errata reports, is
	addressed in this		addressed in this
	document because of the extensive use of NFS4ERR_DELAY		document because of the extensive use of NFS4ERR_DELAY
	in connection with state migration and session migration.		in connection with state migration and session migration.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		<section anchor="CHG-other" numbered="true" toc="default">
	<section title="Other Revisions Made to RFC5661"		<name>Other Revisions Made to RFC 5661</name>
	anchor="CHG-other">		<t>
	<t>		Besides the major reworking of Section <xref target="RFC5661" sectionForma
	Beside the major reworking of Section 11 and the associated revisions to		t="bare" section="11"/> of RFC 5661 <xref target="RFC5661"/> and the associated
	existing operations and errors,		revisions to
	there are a number of		existing operations and errors, there were a number of related changes tha
	related changes that are necessary:		t were necessary:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
	The summary that appeared in Section 1.7.3.3 of		<li>
	RFC5661 <xref target="RFC5661"/> was revised to reflect the changes		The summary in Section <xref target="RFC5661" sectionFormat="bare" secti
	made in the revised <xref target="NEW11"/> above.		on="1.7.3.3"/>
	The updated summary		of RFC 5661 <xref target="RFC5661"/> was revised to reflect the changes
	appears as <xref target="PREP-intro"/> above.		made to
	</t>		<xref target="NEW11" format="default"/> above. The updated summary appe
	<t>		ars as
	The discussion of server scope which appeared in Section 2.10.4 of		<xref target="PREP-intro" format="default"/> above.
	RFC5661 <xref target="RFC5661"/> needed to be replaced,		</li>
	since the previous		<li>
	text appears to require a level of inter-server co-ordination		The discussion of server scope in Section
			<xref target="RFC5661" sectionFormat="bare" section="2.10.4"/> of RFC 56
			61
			<xref target="RFC5661"/> was replaced since it
			appeared to require a level of inter-server coordination
	incompatible with its basic function of avoiding the need for		incompatible with its basic function of avoiding the need for
	a globally uniform means of assigning server_owner values.		a globally uniform means of assigning server_owner values.
	A revised treatment appears in <xref target="Server_Scope"/>.		A revised treatment appears in <xref target="Server_Scope" format="defau
	</t>		lt"/>.
	<t>		</li>
	The discussion of trunking which appeared in Section 2.10.5 of		<li>
	RFC5661 <xref target="RFC5661"/> needed to be revised, to more clearly		The discussion of trunking in Section
			<xref target="RFC5661" sectionFormat="bare" section="2.10.5"/> of RFC 56
			61 <xref target="RFC5661"/>
			was revised to more clearly
	explain the multiple types of trunking support and how the		explain the multiple types of trunking support and how the
	client can be made aware of the existing trunking configuration.		client can be made aware of the existing trunking configuration.
	In addition, while the last paragraph (exclusive of sub-sections) of		In addition, while the last paragraph (exclusive of subsections) of
	that section, dealing with		that section dealing with server_owner changes was literally true,
	server_owner changes, is literally true, it has been a source		it had been a source of confusion. Since the original paragraph could b
	of confusion. Since the existing paragraph can be read as		e read as
	suggesting that such changes be dealt with non-disruptively, the		suggesting that such changes be handled nondisruptively, the
	issue needs to be clarified in the revised section, which appears		issue was clarified in the revised <xref target="Trunking" format="defau
	in <xref target="Trunking"/>.		lt"/>.
	</t>		</li>
	</list>		</ul>
	</t>		</section>
	</section>		</section>
	</section>		<section anchor="SECBAD" numbered="true" toc="default">
	<section title="Security Issues that Need to be Addressed"		<name>Security Issues That Need to Be Addressed</name>
	anchor="SECBAD">		<t>
	<t>
	The following issues in the treatment of security within the NFSv4.1		The following issues in the treatment of security within the NFSv4.1
	specification need to be addressed:		specification need to be addressed:
	<list style="symbols">
	<t>
	The Security Considerations Section of RFC5661 <xref target="RFC5661" />
	is not written in accord with RFC3552 <xref target="RFC3552" />
	(also BCP72). Of particular concern is the fact that the section
	does not
	contain a threat analysis.
	</t>		</t>
	<t>		<ul spacing="normal">
			<li>
			The Security Considerations Section of RFC 5661 <xref target="RFC5661" fo
			rmat="default"/>
			was not written in accordance with RFC 3552 (BCP 72) <xref target="RFC355
			2" format="default"/>.
			Of particular concern was the fact that the section
			did not contain a threat analysis.
			</li>
			<li>
	Initial analysis of the existing security issues with NFSv4.1 has made		Initial analysis of the existing security issues with NFSv4.1 has made
	it likely that a revised Security Considerations		it likely that a revised Security Considerations section for the
	Section for the
	existing protocol (one containing a threat analysis) would be likely		existing protocol (one containing a threat analysis) would be likely
	to conclude that NFSv4.1 does not meet the goal of secure use on the		to conclude that NFSv4.1 does not meet the goal of secure use on the
	internet.		Internet.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		The Security Considerations section of
	The Security Considerations Section of		this document (<xref target="SECCON" format="default"/>) has not been thor
	this document (in <xref target="SECCON"/>) has not been thoroughly		oughly
	revised to correct the difficulties mentioned above. Instead, it has been		revised to correct the difficulties mentioned above. Instead, it has been
	modified to take proper account of issues related to the multi-server		modified to take proper account of issues related to the multi-server
	namespace features discussed in <xref target="NEW11"/>, leaving the		namespace features discussed in <xref target="NEW11" format="default"/>, l eaving the
	incomplete discussion and security weaknesses pretty much as they were.		incomplete discussion and security weaknesses pretty much as they were.
	</t>		</t>
	<t>		<t>
	The following major security issues need to be addressed in a		The following major security issues need to be addressed in a
	satisfactory fashion before an updated Security Considerations section		satisfactory fashion before an updated Security Considerations section
	can be published as part of a bis document for NFSv4.1:		can be published as part of a bis document for NFSv4.1:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li>
			<t>
	The continued use of AUTH_SYS and the security exposures it creates		The continued use of AUTH_SYS and the security exposures it creates
	needs to be addressed. Addressing this issue must not be limited to		need to be addressed. Addressing this issue must not be limited to
	the questions of whether the designation of this as OPTIONAL was		the questions of whether the designation of this as <bcp14>OPTIONAL</bcp1
			4> was
	justified and whether it should be changed.		justified and whether it should be changed.
	<vspace blankLines='1'/>		</t>
	In any event, it may not be possible, at this point, to correct the		<t>
			In any event, it may not be possible at this point to correct the
	security problems created by continued use of AUTH_SYS simply by		security problems created by continued use of AUTH_SYS simply by
	revising this designation.		revising this designation.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	The lack of attention within the protocol to the possibility of		The lack of attention within the protocol to the possibility of
	pervasive monitoring attacks such as those described in RFC7258		pervasive monitoring attacks such as those described in RFC 7258
	<xref target="RFC7258"/> (also BCP188).		<xref target="RFC7258" format="default"/> (also BCP 188).
	<vspace blankLines='1'/>		</t>
	In that connection, the use		<t>
	of CREATE_SESSION without privacy protection needs to be addressed		In that connection, the use of CREATE_SESSION without privacy protection
	as it exposes the session ID to		needs to be addressed
	view by an attacker. This is worrisome as this is precisely the type		as it exposes the session ID to view by an attacker. This is worrisome a
	of protocol artifact alluded to in RFC7258,		s this is precisely the type
			of protocol artifact alluded to in RFC 7258,
	which can enable further mischief on the part of		which can enable further mischief on the part of
	the attacker as it enables denial-of-service attacks which can be		the attacker as it enables denial-of-service attacks that can be
	executed effectively with only a single, normally low-value,		executed effectively with only a single, normally low-value,
	credential, even when RPCSEC_GSS authentication is in use.		credential, even when RPCSEC_GSS authentication is in use.
	</t>		</t>
	<t>		</li>
			<li>
			<t>
	The lack of effective use of privacy and integrity, even where the		The lack of effective use of privacy and integrity, even where the
	infrastructure to support use of RPCSEC_GSS in present,		infrastructure to support use of RPCSEC_GSS is present,
	needs to be addressed.		needs to be addressed.
	<vspace blankLines='1'/>		</t>
			<t>
	In light of the security exposures that		In light of the security exposures that
	this situation creates, it is not enough to define a protocol that		this situation creates, it is not enough to define a protocol that
	could, with the provision of sufficient resources, address the problem.		could address this problem with the provision of sufficient resources.
	Instead, what is needed is a way to provide the necessary security,		Instead, what is needed is a way to provide the necessary security
	with very limited performance costs and without requiring		with very limited performance costs and without requiring
	security infrastructure that experience has shown is difficult for		security infrastructure, which experience has shown is difficult for
	many clients and servers to provide.		many clients and servers to provide.
	</t>		</t>
	</list>		</li>
	</t>		</ul>
	<t>		<t>
	In trying to provide a major security upgrade for a deployed protocol		In trying to provide a major security upgrade for a deployed protocol
	such as NFSv4.1, the working group, and the internet community is likely		such as NFSv4.1, the working group and the Internet community are likely
	to find itself dealing with a number of considerations such as the		to find themselves dealing with a number of considerations such as the
	following:		following:
	<list style="symbols">
	<t>
	The need to accommodate existing deployments of existing protocols
	as specified previously in existing Proposed Standards.
	</t>		</t>
	<t>		<ul spacing="normal">
	The difficulty of effecting changes to existing interoperating		<li>
			The need to accommodate existing deployments of protocols
			specified previously in existing Proposed Standards.
			</li>
			<li>
			The difficulty of effecting changes to existing, interoperating
	implementations.		implementations.
	</t>		</li>
	<t>		<li>
	The difficulty of making changes to NFSv4 protocols other than those in		The difficulty of making changes to NFSv4 protocols other than those in
	the form of OPTIONAL extensions.		the form of <bcp14>OPTIONAL</bcp14> extensions.
	</t>		</li>
	<t>		<li>
	The tendency of those responsible for existing NFSv4 deployments to		The tendency of those responsible for existing NFSv4 deployments to
	ignore security flaws in the context of local area networks under		ignore security flaws in the context of local area networks under
	the mistaken		the mistaken impression that network isolation provides, in and of itself
	impression		, isolation from
	that network isolation provides, in and of itself, isolation from
	all potential attackers.		all potential attackers.
	</t>		</li>
	</list>		</ul>
	</t>		<t>
	<t>		Given that the above-mentioned difficulties apply to minor
	Given that the difficulties mentioned above apply to minor
	version zero as well, it may make sense to deal with these security issues		version zero as well, it may make sense to deal with these security issues
	in a common document applying to all NFSv4 minor versions. If		in a common document that applies to all NFSv4 minor versions. If
	that approach		that approach is taken, the Security Considerations section of an eventual
	is taken the, Security Considerations section of an eventual NFv4.1 bis		NFv4.1 bis
	document would reference that common document and the defining		document would reference that common document, and the defining
	RFCs for other minor versions might do so as well.		RFCs for other minor versions might do so as well.
	</t>		</t>
			</section>
	</section>		<section numbered="false" toc="default">
	<section title="Acknowledgments">		<name>Acknowledgments</name>
	<section title="Acknowledgments for this Update"		<section toc="exclude" numbered="false">
	toc="exclude">		<name>Acknowledgments for This Update</name>
	<t>		<t>
	The authors wish to acknowledge the important role		The authors wish to acknowledge the important role
	of Andy Adamson of Netapp		of <contact fullname="Andy Adamson"/> of Netapp
	in clarifying the need for trunking discovery functionality, and		in clarifying the need for trunking discovery functionality, and
	exploring the role of the file system location attributes in		exploring the role of the file system location attributes in
	providing the		providing the
	necessary support.		necessary support.
	</t>		</t>
	<t>		<t>
	The authors wish to thank Tom Haynes of Hammerspace for drawing our		The authors wish to thank <contact fullname="Tom Haynes"/> of Hammerspace
			for drawing our
	attention to the fact that internationalization and security might		attention to the fact that internationalization and security might
	best be handled in documents dealing with such protocol issues as they		best be handled in documents dealing with such protocol issues as they
	apply to all NFSv4 minor versions.		apply to all NFSv4 minor versions.
	</t>		</t>
	<t>		<t>
	The authors also wish to acknowledge the work of Xuan Qi of Oracle		The authors also wish to acknowledge the work of <contact fullname="Xuan
	with NFSv4.1 client and server prototypes of transparent state		Qi"/> of Oracle
	migration functionality.		with NFSv4.1 client and server prototypes of Transparent State
	</t>		Migration functionality.
	<t>		</t>
			<t>
	The authors wish to thank others that brought attention to important		The authors wish to thank others that brought attention to important
	issues. The comments of Trond Myklebust of Primary Data related		issues. The comments of <contact fullname="Trond Myklebust"/> of Primary Data related
	to trunking helped to clarify the role of DNS in		to trunking helped to clarify the role of DNS in
	trunking discovery. Rick Macklem's comments brought attention to		trunking discovery. <contact fullname="Rick Macklem"/>'s comments broug ht attention to
	problems in the handling of the per-fs version of		problems in the handling of the per-fs version of
	RECLAIM_COMPLETE.		RECLAIM_COMPLETE.
	</t>		</t>
	<t>		<t>
	The authors wish to thank Olga Kornievskaia of Netapp for her helpful		The authors wish to thank <contact fullname="Olga Kornievskaia"/> of Net
			app for her helpful
	review comments.		review comments.
	</t>		</t>
	</section>		</section>
	<section title="Acknowledgments for RFC5661"		<section toc="exclude" numbered="false">
	toc="exclude">		<name>Acknowledgments for RFC 5661</name>
			<t>
	<t>
	The initial text for the SECINFO extensions were edited by		The initial text for the SECINFO extensions were edited by
	Mike Eisler with contributions from Peng Dai, Sergey Klyushin, and		<contact fullname="Mike Eisler"/> with contributions from <contact fullnam
	Carl Burnett.		e="Peng Dai"/>, <contact fullname="Sergey Klyushin"/>, and
	</t>		<contact fullname="Carl Burnett"/>.
	<t>		</t>
			<t>
	The initial text for the SESSIONS extensions were edited by		The initial text for the SESSIONS extensions were edited by
	Tom Talpey, Spencer Shepler, Jon Bauman with contributions from		<contact fullname="Tom Talpey"/>, <contact fullname="Spencer Shepler"/>,
	Charles Antonelli, Brent Callaghan, Mike Eisler, John Howard, Chet		<contact fullname="Jon Bauman"/> with contributions from
	Juszczak, Trond Myklebust, Dave Noveck, John Scott, Mike		<contact fullname="Charles Antonelli"/>, <contact fullname="Brent Ca
	Stolarchuk, and Mark Wittle.		llaghan"/>, <contact fullname="Mike Eisler"/>, <contact fullname="John How
	</t>		ard"/>, <contact fullname="Chet Juszczak"/>, <contact fullname="Trond Mykl
	<t>		ebust"/>, <contact fullname="Dave Noveck"/>, <contact fullname="John Scott
			"/>, <contact fullname="Mike Stolarchuk"/>, and <contact fullname="Mark Wittle"/
			>.
			</t>
			<t>
	Initial text relating to multi-server namespace features,		Initial text relating to multi-server namespace features,
	including the concept of referrals, were contributed by		including the concept of referrals, were contributed by
	Dave Noveck, Carl Burnett, and Charles Fan with contributions		<contact fullname="Dave Noveck"/>, <contact fullname="Carl Burnett"/>,
	from Ted Anderson, Neil Brown, and Jon Haswell.		and <contact fullname="Charles Fan"/> with contributions
	</t>		from <contact fullname="Ted Anderson"/>, <contact fullname="Neil Bro
	<t>		wn"/>, and <contact fullname="Jon Haswell"/>.
			</t>
			<t>
	The initial text for the Directory Delegations support were		The initial text for the Directory Delegations support were
	contributed by Saadia Khan with input from Dave Noveck, Mike		contributed by <contact fullname="Saadia Khan"/> with input from
	Eisler, Carl Burnett, Ted Anderson, and Tom Talpey.		<contact fullname="Dave Noveck"/>, <contact fullname="Mike Eisler"/>,
	</t>		<contact fullname="Carl Burnett"/>, <contact fullname="Ted Anderson"/>,
	<t>		and <contact fullname="Tom Talpey"/>.
			</t>
			<t>
	The initial text for the ACL explanations were contributed by		The initial text for the ACL explanations were contributed by
	Sam Falkner and Lisa Week.		<contact fullname="Sam Falkner"/> and <contact fullname="Lisa Week"/>.
	</t>		</t>
	<t>		<t>
	The pNFS work was inspired by the NASD and OSD		The pNFS work was inspired by the NASD and OSD
	work done by Garth Gibson. Gary Grider has also		work done by <contact fullname="Garth Gibson"/>. <contact fullname="Gary Grider"/> has also
	been a champion of high-performance parallel I/O.		been a champion of high-performance parallel I/O.
	Garth Gibson and Peter Corbett started the pNFS		<contact fullname="Garth Gibson"/> and <contact fullname="Peter Corbett"/> started the pNFS
	effort with a problem statement document for the IETF		effort with a problem statement document for the IETF
	that formed the basis for the pNFS work in NFSv4.1.		that formed the basis for the pNFS work in NFSv4.1.
	</t>		</t>
	<t>		<t>
	The initial text for the parallel NFS support was edited by		The initial text for the parallel NFS support was edited by
	Brent Welch and Garth Goodson. Additional authors for those		<contact fullname="Brent Welch"/> and <contact fullname="Garth Goodson"/>.
	documents were Benny Halevy, David Black, and Andy Adamson.		Additional authors for those
			documents were <contact fullname="Benny Halevy"/>, <contact fullname="Davi
			d Black"/>, and <contact fullname="Andy Adamson"/>.
	Additional input came from the informal group that contributed		Additional input came from the informal group that contributed
	to the construction of the initial pNFS drafts; specific		to the construction of the initial pNFS drafts; specific
	acknowledgment goes to Gary Grider, Peter Corbett, Dave Noveck,		acknowledgment goes to <contact fullname="Gary Grider"/>, <contact fullnam
	Peter Honeyman, and Stephen Fridella.		e="Peter Corbett"/>, <contact fullname="Dave Noveck"/>,
	</t>		<contact fullname="Peter Honeyman"/>, and <contact fullname="Stephen Fride
	<t>		lla"/>.
	Fredric Isaman found several errors in draft versions of the		</t>
			<t>
			<contact fullname="Fredric Isaman"/> found several errors in draft version
			s of the
	ONC RPC XDR description of the NFSv4.1 protocol.		ONC RPC XDR description of the NFSv4.1 protocol.
	</t>		</t>
	<t>		<t>
	Audrey Van Belleghem provided, in numerous ways, essential		<contact fullname="Audrey Van Belleghem"/> provided, in numerous ways, ess
	co-ordination and management of the process of editing the		ential
			coordination and management of the process of editing the
	specification documents.		specification documents.
	</t>		</t>
	<t>		<t>
	Richard Jernigan gave feedback on the file layout's striping		<contact fullname="Richard Jernigan"/> gave feedback on the file layout's
			striping
	pattern design.		pattern design.
	</t>		</t>
	<t>		<t>
	Several formal inspection teams were formed to review various		Several formal inspection teams were formed to review various
	areas of the protocol. All the inspections found significant		areas of the protocol. All the inspections found significant
	errors and room for improvement. NFSv4.1's inspection teams		errors and room for improvement. NFSv4.1's inspection teams
	were:		were:
	<list style="symbols">		</t>
	<t>		<ul spacing="normal">
			<li><t>
	ACLs, with the following inspectors:		ACLs, with the following inspectors:
	Sam Falkner,		<contact fullname="Sam Falkner"/>,
	Bruce Fields,		<contact fullname="Bruce Fields"/>,
	Rahul Iyer,		<contact fullname="Rahul Iyer"/>,
	Saadia Khan,		<contact fullname="Saadia Khan"/>,
	Dave Noveck,		<contact fullname="Dave Noveck"/>,
	Lisa Week,		<contact fullname="Lisa Week"/>,
	Mario Wurzl,		<contact fullname="Mario Wurzl"/>,
	and		and
			<contact fullname="Alan Yoder"/>.</t>
	Alan Yoder.		</li>
			<li><t>
	</t>
	<t>
	Sessions, with the following inspectors:		Sessions, with the following inspectors:
	William Brown,		<contact fullname="William Brown"/>,
	Tom Doeppner,		<contact fullname="Tom Doeppner"/>,
	Robert Gordon,		<contact fullname="Robert Gordon"/>,
	Benny Halevy,		<contact fullname="Benny Halevy"/>,
	Fredric Isaman,		<contact fullname="Fredric Isaman"/>,
	Rick Macklem,		<contact fullname="Rick Macklem"/>,
	Trond Myklebust,		<contact fullname="Trond Myklebust"/>,
	Dave Noveck,		<contact fullname="Dave Noveck"/>,
	Karen Rochford,		<contact fullname="Karen Rochford"/>,
	John Scott,		<contact fullname="John Scott"/>,
	and		and
			<contact fullname="Peter Shah"/>.</t>
	Peter Shah.		</li>
			<li><t>
	</t>
	<t>
	Initial pNFS inspection, with the following inspectors:		Initial pNFS inspection, with the following inspectors:
	Andy Adamson,		<contact fullname="Andy Adamson"/>,
	David Black,		<contact fullname="David Black"/>,
	Mike Eisler,		<contact fullname="Mike Eisler"/>,
	Marc Eshel,		<contact fullname="Marc Eshel"/>,
	Sam Falkner,		<contact fullname="Sam Falkner"/>,
	Garth Goodson,		<contact fullname="Garth Goodson"/>,
	Benny Halevy,		<contact fullname="Benny Halevy"/>,
	Rahul Iyer,		<contact fullname="Rahul Iyer"/>,
	Trond Myklebust,		<contact fullname="Trond Myklebust"/>,
	Spencer Shepler,		<contact fullname="Spencer Shepler"/>,
	and		and
			<contact fullname="Lisa Week"/>.</t>
	Lisa Week.		</li>
			<li><t>
	</t>
	<t>
	Global namespace, with the following inspectors:		Global namespace, with the following inspectors:
	Mike Eisler,		<contact fullname="Mike Eisler"/>,
	Dan Ellard,		<contact fullname="Dan Ellard"/>,
	Craig Everhart,		<contact fullname="Craig Everhart"/>,
	Fredric Isaman,		<contact fullname="Fredric Isaman"/>,
	Trond Myklebust,		<contact fullname="Trond Myklebust"/>,
	Dave Noveck,		<contact fullname="Dave Noveck"/>,
	Theresa Raj,		<contact fullname="Theresa Raj"/>,
	Spencer Shepler,		<contact fullname="Spencer Shepler"/>,
	Renu Tewari,		<contact fullname="Renu Tewari"/>,
			and
	and		<contact fullname="Robert Thurlow"/>.</t>
			</li>
	Robert Thurlow.		<li><t>
	</t>
	<t>
	NFSv4.1 file layout type, with the following inspectors:		NFSv4.1 file layout type, with the following inspectors:
	Andy Adamson,		<contact fullname="Andy Adamson"/>,
	Marc Eshel,		<contact fullname="Marc Eshel"/>,
	Sam Falkner,		<contact fullname="Sam Falkner"/>,
	Garth Goodson,		<contact fullname="Garth Goodson"/>,
	Rahul Iyer,		<contact fullname="Rahul Iyer"/>,
	Trond Myklebust,		<contact fullname="Trond Myklebust"/>,
	and		and
	Lisa Week.		<contact fullname="Lisa Week"/>.</t>
	</t>		</li>
			<li><t>
	<t>
	NFSv4.1 locking and directory delegations, with the following inspectors:		NFSv4.1 locking and directory delegations, with the following inspectors:
	Mike Eisler,		<contact fullname="Mike Eisler"/>,
	Pranoop Erasani,		<contact fullname="Pranoop Erasani"/>,
	Robert Gordon,		<contact fullname="Robert Gordon"/>,
	Saadia Khan,		<contact fullname="Saadia Khan"/>,
	Eric Kustarz,		<contact fullname="Eric Kustarz"/>,
	Dave Noveck,		<contact fullname="Dave Noveck"/>,
	Spencer Shepler,		<contact fullname="Spencer Shepler"/>,
	and		and
	Amy Weaver.		<contact fullname="Amy Weaver"/>.</t>
	</t>		</li>
			<li><t>
	<t>
	EXCHANGE_ID and DESTROY_CLIENTID, with the following inspectors:		EXCHANGE_ID and DESTROY_CLIENTID, with the following inspectors:
	Mike Eisler,		<contact fullname="Mike Eisler"/>,
	Pranoop Erasani,		<contact fullname="Pranoop Erasani"/>,
	Robert Gordon,		<contact fullname="Robert Gordon"/>,
	Benny Halevy,		<contact fullname="Benny Halevy"/>,
	Fredric Isaman,		<contact fullname="Fredric Isaman"/>,
	Saadia Khan,		<contact fullname="Saadia Khan"/>,
	Ricardo Labiaga,		<contact fullname="Ricardo Labiaga"/>,
	Rick Macklem,		<contact fullname="Rick Macklem"/>,
	Trond Myklebust,		<contact fullname="Trond Myklebust"/>,
	Spencer Shepler,		<contact fullname="Spencer Shepler"/>,
	and		and
			<contact fullname="Brent Welch"/>.</t>
			</li>
	Brent Welch.		<li><t>
	</t>
	<t>
	Final pNFS inspection, with the following inspectors:		Final pNFS inspection, with the following inspectors:
	Andy Adamson,		<contact fullname="Andy Adamson"/>,
	Mike Eisler,		<contact fullname="Mike Eisler"/>,
	Mark Eshel,		<contact fullname="Mark Eshel"/>,
	Sam Falkner,		<contact fullname="Sam Falkner"/>,
	Jason Glasgow,		<contact fullname="Jason Glasgow"/>,
	Garth Goodson,		<contact fullname="Garth Goodson"/>,
	Robert Gordon,		<contact fullname="Robert Gordon"/>,
	Benny Halevy,		<contact fullname="Benny Halevy"/>,
	Dean Hildebrand,		<contact fullname="Dean Hildebrand"/>,
	Rahul Iyer,		<contact fullname="Rahul Iyer"/>,
	Suchit Kaura,		<contact fullname="Suchit Kaura"/>,
	Trond Myklebust,		<contact fullname="Trond Myklebust"/>,
	Anatoly Pinchuk,		<contact fullname="Anatoly Pinchuk"/>,
	Spencer Shepler,		<contact fullname="Spencer Shepler"/>,
	Renu Tewari,		<contact fullname="Renu Tewari"/>,
	Lisa Week,		<contact fullname="Lisa Week"/>,
	and		and
			<contact fullname="Brent Welch"/>.</t>
	Brent Welch.		</li>
			</ul>
	</t>		<t>
	</list>
	</t>
	<t>
	A review team worked together to generate the tables of assignments of		A review team worked together to generate the tables of assignments of
	error sets to operations and make sure that each such assignment had		error sets to operations and make sure that each such assignment had
	two or more people validating it. Participating in the process were		two or more people validating it. Participating in the process were
	Andy Adamson,		<contact fullname="Andy Adamson"/>,
	Mike Eisler,		<contact fullname="Mike Eisler"/>,
	Sam Falkner,		<contact fullname="Sam Falkner"/>,
	Garth Goodson,		<contact fullname="Garth Goodson"/>,
	Robert Gordon,		<contact fullname="Robert Gordon"/>,
	Trond Myklebust,		<contact fullname="Trond Myklebust"/>,
	Dave Noveck,		<contact fullname="Dave Noveck"/>,
	Spencer Shepler,		<contact fullname="Spencer Shepler"/>,
	Tom Talpey,		<contact fullname="Tom Talpey"/>,
	Amy Weaver,		<contact fullname="Amy Weaver"/>,
	and		and
	Lisa Week.		<contact fullname="Lisa Week"/>.
	</t>		</t>
	<t>		<t>
	Jari Arkko, David Black, Scott Bradner, Lisa		<contact fullname="Jari Arkko"/>, <contact fullname="David Black"/>,
	Dusseault, Lars Eggert, Chris Newman, and Tim		<contact fullname="Scott Bradner"/>, <contact fullname="Lisa Dusseault"/
	Polk provided valuable review and guidance.		>, <contact fullname="Lars Eggert"/>, <contact fullname="Chris Newman"/>, an
			d <contact fullname="Tim Polk"/> provided valuable review and guidance.
	</t>
	<t>
	Olga Kornievskaia found several errors in the SSV specification.
	</t>
	<t>		</t>
	Ricardo Labiaga found several places where the use of RPCSEC_GSS		<t>
			<contact fullname="Olga Kornievskaia"/> found several errors in the SSV speci
			fication.
			</t>
			<t>
			<contact fullname="Ricardo Labiaga"/> found several places where the use of R
			PCSEC_GSS
	was underspecified.		was underspecified.
	</t>		</t>
			<t>
	<t>
	Those who provided miscellaneous comments include:		Those who provided miscellaneous comments include:
	Andy Adamson, Sunil Bhargo, Alex Burlyga, Pranoop Erasani,		<contact fullname="Andy Adamson"/>, <contact fullname="Sunil Bhargo"/>,
	Bruce Fields, Vadim Finkelstein, Jason Goldschmidt, Vijay		<contact fullname="Alex Burlyga"/>, <contact fullname="Pranoop Erasani"/>,
	K. Gurbani, Sergey Klyushin, Ricardo Labiaga, James Lentini, Anshul		<contact fullname="Bruce Fields"/>, <contact fullname="Vadim Finkelstein"/
	Madan, Daniel Muntz, Daniel Picken, Archana Ramani, Jim Rees, Mahesh		>, <contact fullname="Jason Goldschmidt"/>, <contact fullname="Vijay K. Gurba
	Siddheshwar, Tom Talpey, and Peter Varga.		ni"/>, <contact fullname="Sergey Klyushin"/>, <contact fullname="Ricardo Labiaga
			"/>, <contact fullname="James Lentini"/>, <contact fullname="Anshul Madan"/>,
	</t>		<contact fullname="Daniel Muntz"/>, <contact fullname="Daniel Picken"/>, <co
			ntact fullname="Archana Ramani"/>, <contact fullname="Jim Rees"/>, <contact f
	</section>		ullname="Mahesh Siddheshwar"/>, <contact fullname="Tom Talpey"/>, and <contac
	</section>		t fullname="Peter Varga"/>.
	</back>
			</t>
			</section>
			</section>
			</back>
	</rfc>		</rfc>
End of changes. 5934 change blocks.
	21265 lines changed or deleted		20627 lines changed or added
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