Pull more fscache updates from David Howells:
 "A set of fixes and minor updates for the fscache rewrite:

   - Fix mishandling of volume collisions (the wait condition is
     inverted and so it was only waiting if the volume collision was
     already resolved).

   - Fix miscalculation of whether there's space available in
     cachefiles.

   - Make sure a default cache name is set on a cache if the user hasn't
     set one by the time they bind the cache.

   - Adjust the way the backing inode is presented in tracepoints, add a
     tracepoint for mkdir and trace directory lookup.

   - Add a tracepoint for failure to set the active file mark.

   - Add an explanation of the checks made on the backing filesystem.

   - Check that the backing filesystem supports tmpfile.

   - Document how the page-release cancellation of the read-skip
     optimisation works.

  And I've included a change for netfslib:

   - Make ops->init_rreq() optional"

* tag 'fscache-fixes-20220121' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  netfs: Make ops->init_rreq() optional
  fscache: Add a comment explaining how page-release optimisation works
  cachefiles: Check that the backing filesystem supports tmpfiles
  cachefiles: Explain checks in a comment
  cachefiles: Trace active-mark failure
  cachefiles: Make some tracepoint adjustments
  cachefiles: set default tag name if it's unspecified
  cachefiles: Calculate the blockshift in terms of bytes, not pages
  fscache: Fix the volume collision wait condition