rfc9766.original.xml		rfc9766.xml
	<?xml version='1.0' encoding='utf-8'?>		<?xml version='1.0' encoding='utf-8'?>
	<!DOCTYPE rfc>
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	<rfc		<!DOCTYPE rfc [
	category='std'		<!ENTITY nbsp "&#160;">
	docName='draft-ietf-nfsv4-layoutwcc-07'		<!ENTITY zwsp "&#8203;">
	ipr='trust200902'		<!ENTITY nbhy "&#8209;">
	obsoletes=''		<!ENTITY wj "&#8288;">
	scripts='Common,Latin'		]>
	sortRefs='true'
	submissionType='IETF'		<rfc xmlns:xi="http://www.w3.org/2001/XInclude" category='std' docName='draft-ie
	symRefs='true'		tf-nfsv4-layoutwcc-07' number="9766" ipr='trust200902' obsoletes='' updates="" s
	tocDepth='3'		ortRefs='true' submissionType='IETF' symRefs='true' tocDepth='3' tocInclude='tru
	tocInclude='true'		e' version='3' consensus='true' xml:lang='en'>
	version='3'
	consensus='true'
	xml:lang='en'>
	<front>		<front>
	<title abbrev='LAYOUT_WCC'>		<title abbrev="WCC in NFSv4.2's Flexible File Layout">Extensions for Weak Cach
	Add LAYOUT_WCC to NFSv4.2's Flex File Layout Type		e Consistency in NFSv4.2's Flexible File Layout
	</title>		</title>
	<seriesInfo name='Internet-Draft' value='draft-ietf-nfsv4-layoutwcc-07'/>		<seriesInfo name='RFC' value='9766'/>
	<author fullname='Thomas Haynes' initials='T.' surname='Haynes'>		<author fullname='Thomas Haynes' initials='T.' surname='Haynes'>
	<organization abbrev='Hammerspace'>Hammerspace</organization>		<organization abbrev='Hammerspace'>Hammerspace</organization>
	<address>		<address>
	<email>loghyr@gmail.com</email>		<email>loghyr@gmail.com</email>
	</address>		</address>
	</author>		</author>
	<author fullname='Trond Myklebust' initials='T.' surname='Myklebust'>		<author fullname='Trond Myklebust' initials='T.' surname='Myklebust'>
	<organization abbrev='Hammerspace'>Hammerspace</organization>		<organization abbrev='Hammerspace'>Hammerspace</organization>
	<address>		<address>
	<email>trondmy@hammerspace.com</email>		<email>trondmy@hammerspace.com</email>
	</address>		</address>
	</author>		</author>
	<date year='2025' month='February' day='07'/>		<date year='2025' month='April'/>
	<area>Transport</area>		<area>WIT</area>
	<workgroup>Network File System Version 4</workgroup>		<workgroup>nfsv4</workgroup>
	<keyword>NFSv4</keyword>
	<abstract>		<abstract>
	<t>		<t>
	This document specifies extensions to the parallel Network		This document specifies extensions to NFSv4.2 for improving Weak Cache
	File System (NFS) version 4 (pNFS) for improving write cache		Consistency (WCC). These extensions introduce mechanisms that ensure
	consistency. These extensions introduce mechanisms that ensure		partial writes performed under a Parallel NFS (pNFS) layout remain
	partial writes performed under a pNFS layout remain coherent and		coherent and correctly tracked. The solution addresses concurrency and
	correctly tracked. The solution addresses concurrency and data		data integrity concerns that may arise when multiple clients write to
	integrity concerns that may arise when multiple clients write to
	the same file through separate data servers. By defining additional		the same file through separate data servers. By defining additional
	interactions among clients, metadata servers, and data servers, this		interactions among clients, metadata servers, and data servers, this
	specification enhances the reliability of NFSv4 in parallel-access		specification enhances the reliability of NFSv4 in parallel-access
	environments and ensures consistency across diverse deployment		environments and ensures consistency across diverse deployment
	scenarios.		scenarios.
	</t>		</t>
	</abstract>		</abstract>
	<note removeInRFC='true'>
	<t>
	Discussion of this draft takes place
	on the NFSv4 working group mailing list (nfsv4@ietf.org),
	which is archived at
	<eref target='https://mailarchive.ietf.org/arch/browse/nfsv4/'/>.
	Working Group information can be found at
	<eref target='https://datatracker.ietf.org/wg/nfsv4/about/'/>.
	</t>
	</note>
	</front>		</front>
	<middle>		<middle>
	<section anchor='sec_intro' numbered='true' removeInRFC='false' toc='default'>		<section anchor='sec_intro' numbered='true' toc='default'>
	<name>Introduction</name>		<name>Introduction</name>
	<t>		<t>
	In the Network File System version 4 (NFSv4) with a Parallel NFS		In the Parallel NFS (pNFS)
	(pNFS) Flexible File Layout (see Section 12 of <xref target='RFC8435' format		flexible file layout (see <xref target='RFC8435'/>), there is no mechanism f
	='default'		or the data servers to
	sectionFormat='of'/>) server, there is no mechanism for the data		update the metadata servers when the data portion of the file is
	servers to update the metadata servers for when the data portion		modified. The metadata server needs this knowledge to correspondingly
	of the file is modified. The metadata server needs this knowledge		update the metadata portion of the file. If the client is using NFSv3 as
	to correspondingly update the metadata portion of the file. If the		the protocol with the data server, it can leverage Weak Cache Consistency
	client is using NFSv3 as the protocol with the data server, it can		(WCC) to update the metadata server of the attribute changes. In this
	leverage weak cache consistency (WCC) to update the metadata server		document, we introduce a new operation called LAYOUT_WCC to NFSv4.2, which
	of the attribute changes. In this document, we introduce a new		allows the client to periodically report the attributes of the data files
	operation called LAYOUT_WCC to NFSv4.2 which allows the client to periodical		to the metadata server.
	ly
	report the attributes of the data files to the metadata server.
	</t>		</t>
	<t>		<t>
	Using the process detailed in <xref target='RFC8178' format='default'		Using the process detailed in <xref target='RFC8178' format='default'/>, the
	sectionFormat='of'/>, the revisions in this document become an		revisions in this document become an
	extension of NFSv4.2 <xref target='RFC7862' format='default'		extension of NFSv4.2 <xref target='RFC7862' format='default'/>. They are bui
	sectionFormat='of'/>. They are built on top of the external data		lt on top of the External Data
	representation (XDR) <xref target='RFC4506' format='default'		Representation (XDR) <xref target='RFC4506' format='default'/> generated fro
	sectionFormat='of'/> generated from <xref target='RFC7863'		m <xref target='RFC7863'
	format='default' sectionFormat='of'/>.		format='default'/>.
	</t>		</t>
	<section anchor='sec_defs' numbered='true' removeInRFC='false' toc='default'>		<section anchor='sec_defs' numbered='true' toc='default'>
	<name>Definitions</name>		<name>Definitions</name>
	<t>		<t>
	For a more comprehensive set of definitions, see Section 1.1 of <xref targ		For a more comprehensive set of definitions, see <xref target='RFC8435'
	et='RFC8435' format='default'		sectionFormat='of' section="1.1"/>.
	sectionFormat='of'/>.
	</t>		</t>
	<dl newline='false' spacing='normal'>		<dl newline='false' spacing='normal'>
	<dt>(file) data:</dt>		<dt>(file) data:</dt>
	<dd>		<dd>
	that part of the file system object that contains the		that part of the file system object that contains the
	data to be read or written. It is the contents of the object		data to be read or written. It is the contents of the object
	rather than the attributes of the object.		rather than the attributes of the object.
	</dd>		</dd>
	<dt>data server (DS):</dt>		<dt>data server (DS):</dt>
	skipping to change at line 136 ¶		skipping to change at line 113 ¶
	<dd>		<dd>
	the pNFS server that provides metadata		the pNFS server that provides metadata
	information for a file system object.		information for a file system object.
	</dd>		</dd>
	<dt>storage device:</dt>		<dt>storage device:</dt>
	<dd>		<dd>
	the target to which clients may direct I/O requests		the target to which clients may direct I/O requests
	when they hold an appropriate layout. Note that each data server		when they hold an appropriate layout. Note that each data server
	is a storage device but that some storage device are not data		is a storage device but that some storage device are not data
	servers. (See Section 2.1 of <xref target='RFC8434' format='default' sec tionFormat='of'/>		servers. (See <xref target='RFC8434' sectionFormat='of' section="2.1"/>
	for a discussion on the difference between a data server		for a discussion on the difference between a data server
	and a storage device.)		and a storage device.)
	</dd>		</dd>
	<dt>weak cache consistency (WCC):</dt>		<dt>weak cache consistency (WCC):</dt>
	<dd>		<dd>
	In NFSv3, WCC allows the client to check for file attribute changes		the mechanism in NFSv3 that allows the client to check for file attribut
	before and after an operation (See Section 2.6 of <xref target='RFC1813'		e changes
	format='default' sectionFormat='of'/>).		before and after an operation (see <xref target='RFC1813'
			sectionFormat='of' section="2.6"/>).
	</dd>		</dd>
	</dl>		</dl>
	</section>		</section>
	<section numbered='true' removeInRFC='false' toc='default'>		<section numbered='true' toc='default'>
	<name>Requirements Language</name>		<name>Requirements Language</name>
	<t>		<t>
	The key words '<bcp14>MUST</bcp14>', '<bcp14>MUST NOT</bcp14>',		The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14>REQU
	'<bcp14>REQUIRED</bcp14>', '<bcp14>SHALL</bcp14>', '<bcp14>SHALL		IRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL
	NOT</bcp14>', '<bcp14>SHOULD</bcp14>', '<bcp14>SHOULD NOT</bcp14>',		NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>
	'<bcp14>RECOMMENDED</bcp14>', '<bcp14>NOT RECOMMENDED</bcp14>',		RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
	'<bcp14>MAY</bcp14>', and '<bcp14>OPTIONAL</bcp14>' in this		"<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are to
	document are to be interpreted as described in BCP 14 <xref		be interpreted as
	target='RFC2119' format='default' sectionFormat='of'/> <xref		described in BCP&nbsp;14 <xref target="RFC2119"/> <xref target="RFC8174"/>
	target='RFC8174' format='default' sectionFormat='of'/> when,		when, and only when, they appear in all capitals, as shown here.
	and only when, they appear in all capitals, as shown here.		</t>
	</t>
	</section>		</section>
	</section>		</section>
	<section anchor='wcc' numbered='true' removeInRFC='false' toc='default'>		<section anchor='wcc' numbered='true' toc='default'>
	<name>Weak Cache Consistency (WCC)</name>		<name>Weak Cache Consistency (WCC)</name>
	<t>		<t>
	A pNFS layout type enables the metadata server to inform the client		A pNFS layout type enables the metadata server to inform the client of
	of both the storage protocol and the locations of the data that the		both the storage protocol and the locations of the data that the client
	client should use when communicating with the storage devices. The		should use when communicating with the storage devices. The flexible
	Flex Files Layout Type, as specified in <xref target='RFC8435'		file layout type, as specified in <xref target='RFC8435' />, describes
	/>, describes how data servers using NFSv3 can be accessed. The		how data servers using NFSv3 can be accessed. The client is restricted
	client is restricted to performing NFSv3 READ (Section 3.3.6		to performing the following NFSv3 operations on the filehandles
	of <xref target='RFC1813'/>), WRITE (Section 3.3.6 of <xref		provided in the layout: READ, WRITE, and COMMIT (see Sections <xref
	target='RFC1813'/>), and COMMIT (Section 3.3.21 of <xref		target='RFC1813' sectionFormat="bare" section="3.3.6"/>, <xref
	target='RFC1813'/>) operations on the file handles provided in the		target='RFC1813' sectionFormat="bare" section="3.3.7"/>, and <xref
	layout. In other words, the client may only use NFSv3 operations		target='RFC1813' sectionFormat="bare" section="3.3.21"/> of <xref
	that act directly on the data portion of the file.		target='RFC1813'/>, respectively). In other words, the client may only us
			e NFSv3
			operations that act directly on the data portion of the file.
	</t>		</t>
	<t>		<t>
	Because		Because there is no control protocol (see <xref target='RFC8434'
	there is no contol protocol (see <xref target='RFC8434' format='default'		format='default' sectionFormat='of'/>) possible with all data servers,
	sectionFormat='of'/>)		NFSv3 is used as the control protocol. As such, the following NFSv3
	possible with all data servers, NFSv3 is used as the control protocol.		operations are commonly used by the metadata server: CREATE, GETATTR,
	As such, the NFSv3 CREATE (see Section 3.3.8 of <xref target='RFC1813'		and SETATTR (see Sections <xref target='RFC1813' section="3.3.8"
	format='default' sectionFormat='of'/>), GETATTR (see Section 3.3.1 of <xr		sectionFormat='bare'/>, <xref target='RFC1813' section="3.3.1"
	ef target='RFC1813'		sectionFormat='bare'/>, and <xref target='RFC1813' section="3.3.2"
	format='default' sectionFormat='of'/>), and SETATTR (see Section 3.3.2 of		sectionFormat='bare'/> of <xref target='RFC1813'/>, respectively). That
	<xref target='RFC1813'		is, the metadata server is only allowed to use NFSv3 operations that
	format='default' sectionFormat='of'/>) are operations commonly		directly act on the metadata portion of the data file. GETATTR allows
	used by the metadata server. I.e., the metadata server is only allowed to		the metadata server to mainly retrieve the mtime (modify time), ctime
	use		(change time), and atime (access time). The metadata server can use
	NFSv3 operations which directly act on the metadata portion of the data f		this information to determine if the client modified the file whilst it
	ile.		held an iomode of LAYOUTIOMODE4_RW (see <xref target='RFC8881'
	GETATTR allows the metadata server to mainly retrieve the mtime (modify t		section="3.3.20" sectionFormat='of'/>). Then it can determine the
	ime),		following for the metadata file: time_modify, time_metadata, and
	ctime (change time), and atime (access time). The metadata server		time_access (see Sections <xref target='RFC8881' section="5.8.2.43"
	can use this information to determine if the client modified the		sectionFormat='bare'/>, <xref target='RFC8881' section="5.8.2.42"
	file whilst it held an iomode of LAYOUTIOMODE4_RW (see Section 3.3.20		sectionFormat='bare'/>, and <xref target='RFC8881' section="5.8.2.37"
	of <xref target='RFC8881' format='default' sectionFormat='of'/>). Then		sectionFormat='bare'/> of <xref target='RFC8881'/>, respectively). That
	it can determine the time_modify (see Section 5.8.2.43		is, it can determine the information to return to clients in an NFSv4.2
	of <xref target='RFC8881' format='default' sectionFormat='of'/>), time_me		GETATTR response.
	tadata (see Section 5.8.2.42
	of <xref target='RFC8881' format='default' sectionFormat='of'/>), and tim
	e_access (see Section 5.8.2.37
	of <xref target='RFC8881' format='default' sectionFormat='of'/>) for
	the metadata file. I.e., the information to return to clients
	in a NFSv4.2 GETATTR response.
	</t>		</t>
	<t>		<t>
	For example, the metadata server might issue an NFSv3 GETATTR		For example, the metadata server might issue an NFSv3 GETATTR operation
	operation to the data server, which is typically triggered by		to the data server, which is typically triggered by a client's NFSv4
	a client's NFSv4 GETATTR request to the metadata server. In		GETATTR request to the metadata server. In addition to the cost of each
	addition to the cost of each individual GETATTR operation,		individual GETATTR operation, the data server can be overwhelmed by a
	the data server can be overwhelmed by a large volume of such		large volume of such requests. NFSv3 addressed a similar challenge by
	requests. NFSv3 addressed a similar challenge by including a		including a post-operation attribute in the READ and WRITE operations
	post-operation attribute in the READ and WRITE operations to		to report WCC data (see <xref target='RFC1813'
	report weak cache consistency (WCC) data (see Section 2.6 of		sectionFormat="of" section="2.6"/>).
	<xref target='RFC1813' />).
	</t>		</t>
	<t>		<t>
	Each NFSv3 operation entails a single round trip between the		Each NFSv3 operation entails a single round trip between the
	client and server. Consequently, issuing a WRITE followed by		client and server. Consequently, issuing a WRITE followed by
	a GETATTR would require two round trips. In that situation, the		a GETATTR would require two round trips. In that situation, the
	retrieved attribute information is regarded as strict server-client		retrieved attribute information is regarded as having strict server-clien t
	consistency. By contrast, NFSv4 enables a WRITE and GETATTR to		consistency. By contrast, NFSv4 enables a WRITE and GETATTR to
	be combined within a compound operation, which requires only		be combined within a compound operation, which requires only
	one round trip. This combined approach is likewise considered		one round trip. This combined approach is likewise considered to have
	strict server-client consistency. Essentially, NFSv4 READ and		strict server-client consistency. Essentially, NFSv4 READ and
	WRITE operations omit post-operation attributes, allowing the		WRITE operations omit post-operation attributes, allowing the
	client to determine whether it requires that information.		client to determine whether it requires that information.
	</t>		</t>
	<t>		<t>
	Whilst NFSv4 got rid of the requirement for WCC information to		Whilst NFSv4 got rid of the requirement for WCC information to
	be supplied by the WRITE or READ operations, the introduction		be supplied by the WRITE or READ operations, the introduction
	of pNFS re-introduces the same problem. The metadata server		of pNFS reintroduces the same problem. The metadata server
	has to communicate with the data server in order to get		has to communicate with the data server in order to get
	at the data which could be provided by a WCC model.		the data that could be provided by a WCC model.
	</t>		</t>
	<t>		<t>
	With the flexible file layout type, the client can leverage		With the flexible file layout type, the client can leverage
	the NFSv3 WCC to service the proxying of times (See Section 4 of <xref		the NFSv3 WCC to service the proxying of times (see <xref
	target='I-D.ietf-nfsv4-delstid' format='default' sectionFormat='of'/>).		target='RFC9754' section="5" sectionFormat='of'/>),
	But the granularity of this data is limited. With client side		but the granularity of this data is limited. With client-side
	mirroring (See Section 8 of <xref target='RFC8435' format='default'		mirroring (see <xref target='RFC8435' section="8"
	sectionFormat='of'/>), the client has to aggregate the N mirrored		sectionFormat='of'/>), the client has to aggregate the N mirrored
	files in order to send one piece of information instead of N		files in order to send one piece of information instead of N
	pieces of information. Also, the client is limited to sending		pieces of information. Also, the client is limited to sending
	that information only when it returns the delegation.		that information only when it returns the delegation.
	</t>		</t>
	<t>		<t>
	This document introduces a new NFSv4.2 operation, LAYOUT_WCC,		This document introduces a new NFSv4.2 operation, LAYOUT_WCC,
	which enables the client to provide the metadata server with		which enables the client to provide the metadata server with
	information obtained from the data server. The client is		information obtained from the data server. The client is
	responsible for gathering the NFSv3 WCC data, returned by the		responsible for gathering the NFSv3 WCC data, returned by the
	three permissible NFSv3 operations, and conveying it back to		three permissible NFSv3 operations, and conveying it back to
	the metadata server as part of NFSv4.2 attributes. The metadata		the metadata server as part of NFSv4.2 attributes. The metadata
	server <bcp14>MAY</bcp14> therefore avoid issuing costly NFSv3		server <bcp14>MAY</bcp14> therefore avoid issuing costly NFSv3
	GETATTR calls to the data servers. Because this approach relies		GETATTR calls to the data servers. Because this approach relies
	on a weak model, the metadata server <bcp14>MAY</bcp14> still		on a weak model, the metadata server <bcp14>MAY</bcp14> still
	perform these calls if it chooses to strengthen the model.		perform these calls if it chooses to strengthen the model.
	</t>		</t>
	</section>		</section>
	<section anchor='op_LAYOUT_WCC' numbered='true' removeInRFC='false' toc='default '>		<section anchor='op_LAYOUT_WCC' numbered='true' toc='default'>
	<name>Operation 77: LAYOUT_WCC - Layout Weak Cache Consistency</name>		<name>Operation 77: LAYOUT_WCC - Layout Weak Cache Consistency</name>
	<section toc='exclude' anchor='ss_op_LAYOUT_WCC_A' numbered='true'>
			<section toc='default' anchor='ss_op_LAYOUT_WCC_A' numbered='true'>
	<name>ARGUMENT</name>		<name>ARGUMENT</name>
	<sourcecode name='' type='' markers='true'><![CDATA[		<sourcecode name='' type='xdr' markers='true'><![CDATA[
	/// struct LAYOUT_WCC4args {		/// struct LAYOUT_WCC4args {
	/// stateid4 lowa_stateid;		/// stateid4 lowa_stateid;
	/// layouttype4 lowa_type;		/// layouttype4 lowa_type;
	/// opaque lowa_body<>;		/// opaque lowa_body<>;
	/// };		/// };
	]]></sourcecode>		]]></sourcecode>
	<t>		<t>
	stateid4 is defined in Section 3.3.12 of <xref target='RFC8881'		stateid4 is defined in <xref target='RFC8881' section="3.3.12"
	format='default' sectionFormat='of'/>.		sectionFormat='of'/>. layouttype4 is defined in <xref target='RFC8881'
	layouttype4 is defined in Section 3.3.13 of <xref target='RFC8881'		section="3.3.13" sectionFormat='of'/>.
	format='default' sectionFormat='of'/>.
	</t>		</t>
	</section>		</section>
	<section toc='exclude' anchor='ss_op_LAYOUT_WCC_R' numbered='true'>		<section toc='default' anchor='ss_op_LAYOUT_WCC_R' numbered='true'>
	<name>RESULT</name>		<name>RESULT</name>
	<sourcecode name='' type='' markers='true'><![CDATA[		<sourcecode name='' type='xdr' markers='true'><![CDATA[
	/// struct LAYOUT_WCC4res {		/// struct LAYOUT_WCC4res {
	/// nfsstat4 lowr_status;		/// nfsstat4 lowr_status;
	/// };		/// };
	]]></sourcecode>		]]></sourcecode>
	<t>		<t>
	nfsstat4 is defined in Section 3.2 of <xref target='RFC8881'		nfsstat4 is defined in <xref target='RFC8881'
	format='default' sectionFormat='of'/>.		section="3.2" sectionFormat='of'/>.
	</t>		</t>
	</section>		</section>
	<section toc='exclude' anchor='ss_op_LAYOUT_WCC_D' numbered='true'>		<section toc='default' anchor='ss_op_LAYOUT_WCC_D' numbered='true'>
	<name>DESCRIPTION</name>		<name>DESCRIPTION</name>
	<t>		<t>
	The current filehandle and the lowa_stateid identify the specific		The current filehandle and the lowa_stateid identify the specific
	layout for the LAYOUT_WCC operation. The lowa_type indicates how		layout for the LAYOUT_WCC operation. The lowa_type indicates how
	to interpret the layout-type-specific payload contained in the		to interpret the layout-type-specific payload contained in the
	lowa_body field. The lowa_type is the corresponding value		lowa_body field. The lowa_type is the corresponding value
	from the IANA registry for 'pNFS Layout Types' for the layout		from the "pNFS Layout Types" IANA registry for the layout
	type being used.		type being used.
	</t>		</t>
	<t>		<t>
	The lowa_body contains the data file attributes. The client is		The lowa_body contains the data file attributes. The client is
	responsible for mapping NFSv3 post-operation attributes to the		responsible for mapping NFSv3 post-operation attributes to the
	fattr4 representation. Similar to the behavior of post-operation		fattr4 representation. Similar to the behavior of post-operation
	attributes, the client may ignore these attributes, and the		attributes, the client may ignore these attributes, and the
	server may also choose to ignore any attributes included in		server may also choose to ignore any attributes included in
	LAYOUT_WCC. However, the server can use these attributes to avoid		LAYOUT_WCC. However, the server can use these attributes to avoid
	querying the data server for data file attributes. Because these		querying the data server for data file attributes. Because these
	attributes are optional and the client has no recourse if the		attributes are optional and the client has no recourse if the
	server opts to disregard them, there is no requirement to return		server opts to disregard them, there is no requirement to return
	a bitmap4 indicating which attributes have been accepted in the		a bitmap4 indicating which attributes have been accepted in the
	LAYOUT_WCC result.		LAYOUT_WCC result.
	</t>		</t>
	</section>		</section>
	<section anchor='ss_op_LAYOUT_WCC_impl' numbered='true' removeInRFC='false' t oc='default'>		<section anchor='ss_op_LAYOUT_WCC_impl' numbered='true' toc='default'>
	<name>Implementation</name>		<name>Implementation</name>
	<section anchor='ss_op_LAYOUT_WCC_examples' numbered='true' removeInRFC='fa		<section anchor='ss_op_LAYOUT_WCC_examples' numbered='true' toc='default'>
	lse' toc='default'>		<name>Examples of When to Use LAYOUT_WCC</name>
	<name>Examples of when to use LAYOUT_WCC</name>
	<t>		<t>
	The only way for the metadata server to detect modifications		The only way for the metadata server to detect modifications
	to the data file is to probe the data servers via a GETATTR. It		to the data file is to probe the data servers via a GETATTR. It
	can compare the mtime results across multiple calls to detect a		can compare the mtime results across multiple calls to detect an
	NFSv3 WRITE operation by the client. Likewise, the atime results		NFSv3 WRITE operation by the client. Likewise, the atime results
	indicate the client having issued a NFSv3 READ operation. As such,		indicate the client having issued an NFSv3 READ operation. As such,
	the client can leverage the LAYOUT_WCC operation whenever it		the client can leverage the LAYOUT_WCC operation whenever it
	has the belief that the metadata server would need to refresh		has the belief that the metadata server would need to refresh
	the attributes of the data files. While the client can send a		the attributes of the data files. While the client can send a
	LAYOUT_WCC at any time, there are times it will want to do this		LAYOUT_WCC at any time, there are times it will want to do this
	operation in order to avoid having the metadata server issue		operation in order to avoid having the metadata server issue
	NFSv3 GETATTR requests to the data servers:		NFSv3 GETATTR requests to the data servers:
	</t>		</t>
	<ul spacing='normal'>		<ul spacing='normal'>
	<li>		<li>
	Whenever it sends a GETATTR for any of the following attributes: size		<t>Whenever it sends a GETATTR for any of the following attributes:</
	(see Section 5.8.1.5		t>
	of <xref target='RFC8881' format='default' sectionFormat='of'/>), spa		<ul spacing='normal'>
	ce_used (see Section 5.8.2.25		<li>size (see <xref target='RFC8881' sectionFormat='of'
	of <xref target='RFC8881' format='default' sectionFormat='of'/>), cha		section="5.8.1.5"/>)</li>
	nge (see Section 5.8.1.4		<li>space_used (see <xref target='RFC8881'
	of <xref target='RFC8881' format='default' sectionFormat='of'/>),		sectionFormat='of' section="5.8.2.35"/>)</li>
	time_access (see Section 5.8.2.37		<li>change (see <xref
	of <xref target='RFC8881' format='default' sectionFormat='of'/>), tim		target='RFC8881' sectionFormat='of' section="5.8.1.4"/>)</li>
	e_metadata (see Section 5.8.2.42		<li>time_access (see <xref target='RFC8881' sectionFormat='of'
	of <xref target='RFC8881' format='default' sectionFormat='of'/>), and		section="5.8.2.37"/>)</li>
	time_modify (see Section 5.8.2.43		<li>time_metadata (see <xref target='RFC8881'
	of <xref target='RFC8881' format='default' sectionFormat='of'/>).		sectionFormat='of' section="5.8.2.42"/>)</li>
			<li>time_modify (see
			<xref target='RFC8881' sectionFormat='of'
			section="5.8.2.43"/>)</li>
			</ul>
	</li>		</li>
	<li>		<li>
	Whenever it sends an NFS4ERR_ACCESS error via LAYOUTRETURN or LAYOUTE RROR - it could		Whenever it sends an NFS4ERR_ACCESS error via LAYOUTRETURN or LAYOUTE RROR. It could
	have already gotten the NFSv3 uid and gid values back in the WCC of t he WRITE,		have already gotten the NFSv3 uid and gid values back in the WCC of t he WRITE,
	READ, or COMMIT operation which got the error. Thus it could report t		READ, or COMMIT operation that got the error. Thus, it could report t
	hat information		hat information
	back to the metadata server, saving it from querying that information		back to the metadata server, saving it from querying that information
	via a NFSv3 GETATTR.		via an NFSv3 GETATTR.
	</li>		</li>
	<li>
	Whenever it sends a SETATTR to refresh the proxied times (See Section		<li>
	4 of <xref		Whenever it sends a SETATTR to refresh the proxied times (see <xref
	target='I-D.ietf-nfsv4-delstid' format='default' sectionFormat='of'/>		target='RFC9754' section="5" sectionFormat='of'/>). The metadata serv
	) - the metadata server is		er will
	going to want to correlate these times in order to detect later modif		correlate these times in order to detect later modification to
	ication to
	the data file.		the data file.
	</li>		</li>
	</ul>		</ul>
	</section>		</section>
	<section anchor='ss_op_LAYOUT_WCC_payload' numbered='true' removeInRFC='fal		<section anchor='ss_op_LAYOUT_WCC_payload' numbered='true' toc='default'>
	se' toc='default'>		<name>Examples of What to Send in LAYOUT_WCC</name>
	<name>Examples of what to send in the LAYOUT_WCC</name>
	<t>		<t>
	The NFSv3 attributes returned in the WCC of WRITE, READ, and COMMIT are		The NFSv3 attributes returned in the WCC of WRITE, READ, and COMMIT ope
	a smaller subset		rations are a smaller subset
	of what can be transmitted as a NFSv4 attribute. The mapping of NFSv3 t		of what can be transmitted as an NFSv4 attribute. The mapping of NFSv3
	o NFSv4 attributes		to NFSv4 attributes
	is shown in <xref target='table_mappings'/>.		is shown in <xref target='table_mappings'/>.
	The LAYOUT_WCC <bcp14>MUST</bcp14> provide all of these attributes to t he metadata server.		The LAYOUT_WCC <bcp14>MUST</bcp14> provide all of these attributes to t he metadata server.
	Both the uid and gid are stringified into their respective attributes o f owner and owner_group.		Both the uid and gid are stringified into their respective attributes o f owner and owner_group.
	The reason to provide these two attributes is in case of NFS4ERR_ACCESS , the metadata		In the case of NFS4ERR_ACCESS, the reason to provide these two attribut es is that the metadata
	server can compare what it expects the values of the uid and gid of the data file		server can compare what it expects the values of the uid and gid of the data file
	to be versus the actual values. It can then repair the permissions as n eeded or		to be versus the actual values. It can then repair the permissions as n eeded or
	modify the expected values it has cached.		modify the expected values it has cached.
	</t>		</t>
	<table anchor='table_mappings'>		<table anchor='table_mappings'>
	<name>NFSv3 to NFSv4.2 Attribute Mappings</name>		<name>NFSv3 to NFSv4.2 Attribute Mappings</name>
	<thead>		<thead>
	<tr><th>NFSv3 Attribute</th> <th>NFSv4.2 Attribute</th></tr>		<tr><th>NFSv3 Attribute</th> <th>NFSv4.2 Attribute</th></tr>
	</thead>		</thead>
	skipping to change at line 391 ¶		skipping to change at line 380 ¶
	<tr><td>gid</td> <td>owner_group</td></tr>		<tr><td>gid</td> <td>owner_group</td></tr>
	<tr><td>atime</td> <td>time_access</td></tr>		<tr><td>atime</td> <td>time_access</td></tr>
	<tr><td>mtime</td> <td>time_modify</td></tr>		<tr><td>mtime</td> <td>time_modify</td></tr>
	<tr><td>ctime</td> <td>time_metadata</td></tr>		<tr><td>ctime</td> <td>time_metadata</td></tr>
	</tbody>		</tbody>
	</table>		</table>
	</section>		</section>
	</section>		</section>
	<section anchor='ss_op_LAYOUT_WCC_errs' numbered='true' removeInRFC='false' t oc='default'>		<section anchor='ss_op_LAYOUT_WCC_errs' numbered='true' toc='default'>
	<name>Allowed Errors</name>		<name>Allowed Errors</name>
	<t>		<t>
	The LAYOUT_WCC operation can raise the errors in		The LAYOUT_WCC operation can raise the errors listed in <xref
	<xref target='tbl_op_error_returns' format='default' sectionFormat='of'/>.		target='tbl_op_error_returns' format='default'/>. When an error is
	When an error is encountered, the metadata server can decide to ignore		encountered, the metadata server can decide to ignore the entire
	the entire operation or depending on the layout type		operation, or depending on the layout-type-specific payload, it could
	specific payload, it could decide to apply a portion of the payload.		decide to apply a portion of the payload. Note that there are no new
	Note that there are no new errors introduced for the LAYOUT_WCC		errors introduced for the LAYOUT_WCC operation and the errors in <xref
	operation and the errors in <xref target='tbl_op_error_returns' format='de		target='tbl_op_error_returns' format='default'/> are each defined in
	fault' sectionFormat='of'/>		<xref target='RFC8881' section="15.1" sectionFormat='of'/>. <xref
	are each defined in Section 15.1 of <xref target='RFC8881'		target='tbl_op_error_returns' format='default'/> can be considered as an
	format='default' sectionFormat='of'/>. <xref target='tbl_op_error_returns'		extension of <xref target='RFC8881' section="15.2" sectionFormat='of'/>.
	format='default' sectionFormat='of'/>
	can be considered as an extension of Section 15.2 of <xref target='RFC8881
	'
	format='default' sectionFormat='of'/>.
	</t>		</t>
	<table anchor='tbl_op_error_returns' align='center'>		<table anchor='tbl_op_error_returns' align='center'>
	<name>Operations and Their Valid Errors</name>		<name>Operations and Their Valid Errors</name>
	<thead>		<thead>
	<tr>		<tr>
	<th>Operation</th>		<th>Operation</th>
	<th>Errors</th>		<th>Errors</th>
	</tr>		</tr>
	</thead>		</thead>
	<tbody>		<tbody>
	skipping to change at line 452 ¶		skipping to change at line 440 ¶
	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
	</td>		</td>
	</tr>		</tr>
	</tbody>		</tbody>
	</table>		</table>
	</section>		</section>
	<section anchor='ss_op_LAYOUT_WCC_opt' numbered='true' removeInRFC='false' toc ='default'>		<section anchor='ss_op_LAYOUT_WCC_opt' numbered='true' toc='default'>
	<name>Extension of Existing Implementations</name>		<name>Extension of Existing Implementations</name>
	<t>		<t>
	The new LAYOUT_WCC operation is <bcp14>OPTIONAL</bcp14> for both		The new LAYOUT_WCC operation is <bcp14>OPTIONAL</bcp14> for both
	NFSv4.2 (<xref target='RFC7863' format='default' sectionFormat='of'/>)		NFSv4.2 <xref target='RFC7863' format='default'/>
	and the flexible file layout type (<xref target='RFC8435' format='default'		and the flexible file layout type <xref target='RFC8435' format='default'/
	sectionFormat='of'/>).		>.
	</t>		</t>
	</section>		</section>
	<section anchor='ss_op_LAYOUT_WCC_ff' numbered='true' removeInRFC='false' toc=		<section anchor='ss_op_LAYOUT_WCC_ff' numbered='true' toc='default'>
	'default'>		<name>Flexible File Layout Type</name>
	<name>Flex Files Layout Type</name>		<sourcecode name='' type='xdr' markers='true'><![CDATA[
	<sourcecode name='' type='' markers='true'><![CDATA[
	/// struct ff_data_server_wcc4 {		/// struct ff_data_server_wcc4 {
	/// deviceid4 ffdsw_deviceid;		/// deviceid4 ffdsw_deviceid;
	/// stateid4 ffdsw_stateid;		/// stateid4 ffdsw_stateid;
	/// nfs_fh4 ffdsw_fh_vers<>;		/// nfs_fh4 ffdsw_fh_vers<>;
	/// fattr4 ffdsw_attributes;		/// fattr4 ffdsw_attributes;
	/// };		/// };
	///		///
	/// struct ff_mirror_wcc4 {		/// struct ff_mirror_wcc4 {
	/// ff_data_server_wcc4 ffmw_data_servers<>;		/// ff_data_server_wcc4 ffmw_data_servers<>;
	/// };		/// };
	///		///
	/// struct ff_layout_wcc4 {		/// struct ff_layout_wcc4 {
	/// ff_mirror_wcc4 fflw_mirrors<>;		/// ff_mirror_wcc4 fflw_mirrors<>;
	/// };		/// };
	]]>		]]></sourcecode>
	</sourcecode>
	<t>		<t>
	The flex file layout type specific results <bcp14>MUST</bcp14> correspond		The results specific to the flexible file layout type <bcp14>MUST</bcp14>
	to the ff_layout4 data structure as defined in Section 5.1 of		correspond to the ff_layout4 data structure as defined in <xref
	<xref target='RFC8435' format='default' sectionFormat='of'/>.		target='RFC8435' section="5.1" sectionFormat='of'/>. There
	There <bcp14>MUST</bcp14> be a one-to-one correspondence between:		<bcp14>MUST</bcp14> be a one-to-one correspondence between the following:
	</t>		</t>
	<ul spacing='normal'>		<ul spacing='normal'>
	<li>		<li>
	ff_data_server4 -&gt; ff_data_server_wcc4		ff_data_server4 -&gt; ff_data_server_wcc4
	</li>		</li>
	<li>		<li>
	ff_mirror4 -&gt; ff_mirror_wcc4		ff_mirror4 -&gt; ff_mirror_wcc4
	</li>		</li>
	<li>		<li>
	ff_layout4 -&gt; ff_layout_wcc4		ff_layout4 -&gt; ff_layout_wcc4
	</li>		</li>
	</ul>		</ul>
	<t>		<t>
	Each ff_layout4 has an array of ff_mirror4, which have an array of ff_data _server4.		Each ff_layout4 has an array of ff_mirror4, which has an array of ff_data_ server4.
	Based on the current filehandle and the lowa_stateid, the server can match the		Based on the current filehandle and the lowa_stateid, the server can match the
	reported attributes.		reported attributes.
	</t>		</t>
	<t>		<t>
	But the positional correspondence between the elements is not		But the positional correspondence between the elements is not
	sufficient to determine the attributes to update. Consider the		sufficient to determine the attributes to update. Consider the
	case where a layout had three mirrors and two of them had updated		case where a layout has three mirrors and two of them have updated
	attributes, but the third did not. A client could decide to present		attributes but the third does not. A client could decide to present
	all three mirrors, with one mirror having an attribute mask with		all three mirrors, with one mirror having an attribute mask with
	no attributes present. Or it could decide to present only the		no attributes present. Or it could decide to present only the
	two mirrors which had been changed.		two mirrors that had been changed.
	</t>		</t>
	<t>		<t>
	In either case, the combination of ffdsw_deviceid, ffdsw_stateid, and		In either case, the combination of ffdsw_deviceid, ffdsw_stateid, and
	ffdsw_fh_vers will uniquely identify the attributes to be updated.		ffdsw_fh_vers will uniquely identify the attributes to be updated.
	All three arguments are required. A layout might have multiple data		All three arguments are required. A layout might have multiple data
	files on the same storage device, in which case the ffdsw_deviceid and		files on the same storage device, in which case the ffdsw_deviceid and
	ffdsw_stateid would match, but the ffdsw_fh_vers would not.		ffdsw_stateid would match, but the ffdsw_fh_vers would not.
	</t>		</t>
	<t>		<t>
	The ffdsw_attributes are processed similar to the obj_attributes in		The ffdsw_attributes are processed similar to the obj_attributes in
	the SETATTR arguments (See Section 18.34 of <xref target='RFC8881' format= 'default' sectionFormat='of'/>).		the SETATTR arguments (see <xref target='RFC8881' section="18.30" sectionF ormat='of'/>).
	</t>		</t>
	</section>		</section>
	</section>		</section>
	<section anchor='xdr_desc' numbered='true' removeInRFC='false' toc='default'>		<section anchor='xdr_desc' numbered='true' toc='default'>
	<name>Extraction of XDR</name>		<name>Extraction of XDR</name>
	<t>		<t>
	This document contains the external data representation (XDR)		This document contains the XDR
	<xref target='RFC4506' format='default' sectionFormat='of'/> description of		<xref target='RFC4506' format='default'/> description of the new NFSv4.2 ope
	the new open		ration LAYOUT_WCC.
	flags for delegating the file to the client.
	The XDR description is embedded in this		The XDR description is embedded in this
	document in a way that makes it simple for the reader to extract		document in a way that makes it simple for the reader to extract
	into a ready-to-compile form. The reader can feed this document		into a ready-to-compile form. The reader can feed this document
	into the following shell script to produce the machine-readable		into the following shell script to produce the machine-readable
	XDR description of the new flags:		XDR description of the new NFSv4.2 operation LAYOUT_WCC.
	</t>		</t>
	<sourcecode name='' type='' markers='true'><![CDATA[		<sourcecode name='' type='shell' markers='true'><![CDATA[
	#!/bin/sh		#!/bin/sh
	grep '^ *///' $* | sed 's?^ */// ??' | sed 's?^ *///$??'		grep '^ *///' $* | sed 's?^ */// ??' | sed 's?^ *///$??'
	]]>		]]></sourcecode>
	</sourcecode>
	<t>		<t>
	That is, if the above script is stored in a file called 'extract.sh', and		That is, if the above script is stored in a file called 'extract.sh', and
	this document is in a file called 'spec.txt', then the reader can do:		this document is in a file called 'spec.txt', then the reader can do:
	</t>		</t>
	<sourcecode name='' type='' markers='true'><![CDATA[		<sourcecode name='' type='shell' markers='true'><![CDATA[
	sh extract.sh < spec.txt > layout_wcc.x		sh extract.sh < spec.txt > layout_wcc.x
	]]>		]]></sourcecode>
	</sourcecode>
	<t>		<t>
	The effect of the script is to remove leading white space from each		The effect of the script is to remove leading blank space from each
	line, plus a sentinel sequence of '///'. XDR descriptions with the		line, plus a sentinel sequence of '///'. XDR descriptions with the
	sentinel sequence are embedded throughout the document.		sentinel sequence are embedded throughout the document.
	</t>		</t>
	<t>		<t>
	Note that the XDR code contained in this document depends on types		Note that the XDR code contained in this document depends on types
	from the NFSv4.2 nfs4_prot.x file (generated from <xref target='RFC7863' for		from the NFSv4.2 nfs4_prot.x file (generated from <xref target='RFC7863' for
	mat='default' sectionFormat='of'/>).		mat='default'/>).
	This includes both nfs types that end with a 4, such as offset4,		This includes both nfs types that end with a 4 (such as offset4 and
	length4, etc., as well as more generic types such as uint32_t and		length4) as well as more generic types (such as uint32_t and
	uint64_t.		uint64_t).
	</t>		</t>
	<t>		<t>
	While the XDR can be appended to that from <xref target='RFC7863' format='de fault' sectionFormat='of'/>,		While the XDR can be appended to that from <xref target='RFC7863' format='de fault' sectionFormat='of'/>,
	the various code snippets belong in their respective areas of		the various code snippets belong in their respective areas of
	that XDR.		that XDR.
	</t>		</t>
	<section anchor='code_copyright' numbered='true' removeInRFC='false' toc='defa
	ult'>
	<name>Code Components Licensing Notice</name>
	<t>
	Both the XDR description and the scripts used for extracting the
	XDR description are Code Components as described in Section 4 of
	<xref target='LEGAL' format='default' sectionFormat='of'>'Legal
	Provisions Relating to IETF Documents'</xref>. These Code
	Components are licensed according to the terms of that document.
	</t>
	</section>
	</section>		</section>
	<section anchor='sec_security' numbered='true' removeInRFC='false' toc='default' >		<section anchor='sec_security' numbered='true' toc='default'>
	<name>Security Considerations</name>		<name>Security Considerations</name>
	<t>		<t>
	There are no new security considerations beyond those in		There are no new security considerations beyond those in
	<xref target='RFC8435' format='default' sectionFormat='of'/>.		<xref target='RFC8435' format='default'/>.
	</t>		</t>
	</section>		</section>
	<section anchor='sec_iana' numbered='true' removeInRFC='true' toc='default'>		<section anchor='sec_iana' numbered='true' toc='default'>
	<name>IANA Considerations</name>		<name>IANA Considerations</name>
	<t>		<t>This document has no IANA actions.
	There are no IANA considerations for this document.
	</t>		</t>
	</section>		</section>
	</middle>		</middle>
	<back>		<back>
	<references>		<references>
	<name>References</name>		<name>References</name>
	<references>		<references>
	<name>Normative References</name>		<name>Normative References</name>
	<xi:include xmlns:xi='http://www.w3.org/2001/XInclude'		<xi:include href='https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2119.
	href='https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.2119		xml'/>
	.xml'/>		<xi:include href='https://bib.ietf.org/public/rfc/bibxml/reference.RFC.4506.
	<xi:include xmlns:xi='http://www.w3.org/2001/XInclude'		xml'/>
	href='https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.4506		<xi:include href='https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7862.
	.xml'/>		xml'/>
	<xi:include xmlns:xi='http://www.w3.org/2001/XInclude'		<xi:include href='https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7863.
	href='https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.7862		xml'/>
	.xml'/>		<xi:include href='https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8174.
	<xi:include xmlns:xi='http://www.w3.org/2001/XInclude'		xml'/>
	href='https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.7863		<xi:include href='https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8178.
	.xml'/>		xml'/>
	<xi:include xmlns:xi='http://www.w3.org/2001/XInclude'		<xi:include href='https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8434.
	href='https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8174		xml'/>
	.xml'/>		<xi:include href='https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8435.
	<xi:include xmlns:xi='http://www.w3.org/2001/XInclude'		xml'/>
	href='https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8178		<xi:include href='https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8881.
	.xml'/>		xml'/>
	<xi:include xmlns:xi='http://www.w3.org/2001/XInclude'
	href='https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8434		<!-- draft-ietf-nfsv4-delstid-08 published as RFC 9754 -->
	.xml'/>
	<xi:include xmlns:xi='http://www.w3.org/2001/XInclude'		<xi:include href='https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9754.
	href='https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8435		xml'/>
	.xml'/>
	<xi:include xmlns:xi='http://www.w3.org/2001/XInclude'
	href='https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8881
	.xml'/>
	<xi:include xmlns:xi='http://www.w3.org/2001/XInclude'
	href='https://bib.ietf.org/public/rfc/bibxml3/reference.I-D.ietf-nfsv4-de
	lstid.xml'/>
	</references>		</references>
	<references>		<references>
	<name>Informative References</name>		<name>Informative References</name>
	<xi:include xmlns:xi='http://www.w3.org/2001/XInclude'		<xi:include href='https://bib.ietf.org/public/rfc/bibxml/reference.RFC.1813.
	href='https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.1813		xml'/>
	.xml'/>
	<reference anchor='LEGAL' target='http://trustee.ietf.org/docs/IETF-Trust-Li
	cense-Policy.pdf'>
	<front>
	<title abbrev='Legal Provisions'>Legal Provisions Relating to IETF Docum
	ents</title>
	<author>
	<organization>IETF Trust</organization>
	</author>
	<date month='November' year='2008'/>
	</front>
	</reference>
	</references>		</references>
	</references>		</references>
	<section numbered='true' removeInRFC='false' toc='default'>		<section numbered='false' toc='default'>
	<name>Acknowledgments</name>		<name>Acknowledgments</name>
	<t>		<t><contact fullname="Dave Noveck"/>, <contact fullname="Tigran
	Dave Noveck, Tigran Mkrtchyan, and Rick Macklem provided reviews of the		Mkrtchyan"/>, and <contact fullname="Rick Macklem"/> provided reviews of
	document.		the document.</t>
	</t>
	</section>		</section>
	</back>		</back>
	</rfc>		</rfc>
End of changes. 80 change blocks.
	306 lines changed or deleted		253 lines changed or added
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