nfsv42_middle_minorv.xml

<!-- Copyright (C) The IETF Trust (2012) -->
<!-- Copyright (C) The Internet Society (2012) -->
<section anchor="ss:minorv" title="Minor Versioning">
  <t>
    NFSv4.2 is a minor version of NFSv4 and is built upon NFSv4.1
    as documented in <xref target="RFC5661" /> and
    <xref target="RFC5662" />.
  </t>

  <t>
    NFSv4.2 does not modify the rules applicable to the NFSv4
    versioning process and follows the rules set out in
    <xref target="RFC5661" /> or in standard-track documents updating
    that document (e.g., in an RFC based on
    <xref target="I-D.ietf-nfsv4-versioning" />).
  </t>

  <t>
    NFSv4.2 only defines extensions to NFSv4.1, each of which may
    be supported (or not) independently.  It does not

    <list style='symbols'>
      <t>
        introduce infrastructural features 
      </t>

      <t>
        make existing features MANDATORY to NOT implement
      </t>

      <t>
	change the status of existing features (i.e., by changing
	their status among OPTIONAL, RECOMMENDED, REQUIRED).
      </t>
    </list>
  </t>

  <t>
    The following versioning-related considerations should be noted.

    <list style='symbols'>
      <t>
	When a new case is added to an existing switch, servers
	need to report non-support of that new case by returning
	NFS4ERR_UNION_NOTSUPP.
      </t>

      <t>
	As regards the potential cross-minor-version transfer of
	stateids, Parallel NFS (pNFS) (see Section 12 of <xref target="RFC5661" />)
        implementations of the file mapping type may
	support of use of an NFSv4.2 metadata server (see Sections 1.7.2.2
        and 12.2.2 of <xref target="RFC5661" />) with NFSv4.1
	data servers.  In this context, a stateid returned by an
	NFSv4.2 COMPOUND will be used in an NFSv4.1 COMPOUND directed
	to the data server (see Sections
        <xref target='ss:pnfs:stateids' format="counter" />
        and <xref target='ss:pnfs:flt' format="counter" />).
      </t>
    </list>
  </t>
</section>