Pull xfs fixes from Darrick Wong:
 "This week's pile mitigates some decades-old problems in how extent
  size hints interact with realtime volumes, fixes some failures in
  online shrink, and fixes a problem where directory and symlink
  shrinking on extremely fragmented filesystems could fail.

  The most user-notable change here is to point users at our (new) IRC
  channel on OFTC. Freedom isn't free, it costs folks like you and me;
  and if you don't kowtow, they'll expel everyone and take over your
  channel. (Ok, ok, that didn't fit the song lyrics...)

  Summary:

   - Fix a bug where unmapping operations end earlier than expected,
     which can cause chaos on multi-block directory and symlink shrink
     operations.

   - Fix an erroneous assert that can trigger if we try to transition a
     bmap structure from btree format to extents format with zero
     extents. This was exposed by xfs/538"

* tag 'xfs-5.13-fixes-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: bunmapi has unnecessary AG lock ordering issues
  xfs: btree format inode forks can have zero extents
  xfs: add new IRC channel to MAINTAINERS
  xfs: validate extsz hints against rt extent size when rtinherit is set
  xfs: standardize extent size hint validation
  xfs: check free AG space when making per-AG reservations