lfs changelog [--follow] <replaceable>mdt_name</replaceable> [startrec [endrec]]
lfs changelog_clear <replaceable>mdt_name id endrec</replaceable>
lfs check <replaceable>mds|osts|servers</replaceable>
+lfs data_version [-nrw] <replaceable>filename</replaceable>
lfs df [-i] [-h] [--pool]-p <replaceable>fsname</replaceable>[.<replaceable>pool</replaceable>] [<replaceable>path</replaceable>] [--lazy]
lfs find [[!] --atime|-A [-+]N] [[!] --mtime|-M [-+]N]
[[!] --ctime|-C [-+]N] [--maxdepth|-D N] [--name|-n <replaceable>pattern</replaceable>]
</row>
<row>
<entry nameend="c2" namest="c1">
+ <para>
+ <literal>data_version [-nrw]
+ <replaceable>filename</replaceable></literal>
+ </para>
+ </entry>
+ <entry>
+ <para>Displays the current version of file data. If
+ <literal>-n</literal> is specified, the data version is read
+ without taking a lock. As a consequence, the data version could
+ be outdated if there are dirty caches on filesystem clients, but
+ this option will not force data flushes and has less of an
+ impact on the filesystem. If <literal>-r</literal> is specified,
+ the data version is read after dirty pages on clients are
+ flushed. If <literal>-w</literal> is specified, the data version
+ is read after all caching pages on clients are flushed.
+ </para>
+ <para>
+ Even with <literal>-r</literal> or <literal>-w</literal>, race
+ conditions are possible and the data version should be checked
+ before and after an operation to be confident the data did not
+ change during it.
+ </para>
+ <para>
+ The data version is the sum of the last committed transaction
+ numbers of all data objects of a file. It is used by HSM policy
+ engines for verifying that file data has not been changed during
+ an archive operation or before a release operation, and by OST
+ migration, primarily for verifying that file data has not been
+ changed during a data copy, when done in non-blocking mode.
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry nameend="c2" namest="c1">
<literal>df [-i] [-h] [--pool|-p
<replaceable>fsname</replaceable>[.
<replaceable>pool</replaceable>] [