Pull ext2, ext3 and quota fixes from Jan Kara:
 "Interesting bits are:
   - removal of a special i_mutex locking subclass (I_MUTEX_QUOTA) since
     quota code does not need i_mutex anymore in any unusual way.
   - backport (from ext4) of a fix of a checkpointing bug (missing cache
     flush) that could lead to fs corruption on power failure

  The rest are just random small fixes & cleanups."

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  ext2: trivial fix to comment for ext2_free_blocks
  ext2: remove the redundant comment for ext2_export_ops
  ext3: return 32/64-bit dir name hash according to usage type
  quota: Get rid of nested I_MUTEX_QUOTA locking subclass
  quota: Use precomputed value of sb_dqopt in dquot_quota_sync
  ext2: Remove i_mutex use from ext2_quota_write()
  reiserfs: Remove i_mutex use from reiserfs_quota_write()
  ext4: Remove i_mutex use from ext4_quota_write()
  ext3: Remove i_mutex use from ext3_quota_write()
  quota: Fix double lock in add_dquot_ref() with CONFIG_QUOTA_DEBUG
  jbd: Write journal superblock with WRITE_FUA after checkpointing
  jbd: protect all log tail updates with j_checkpoint_mutex
  jbd: Split updating of journal superblock and marking journal empty
  ext2: do not register write_super within VFS
  ext2: Remove s_dirt handling
  ext2: write superblock only once on unmount
  ext3: update documentation with barrier=1 default
  ext3: remove max_debt in find_group_orlov()
  jbd: Refine commit writeout logic

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

This is based on commit d1f5273e9adb40724a85272f248f210dc4ce919a
ext4: return 32/64-bit dir name hash according to usage type
by Fan Yong <yong.fan@whamcloud.com>

Traditionally ext2/3/4 has returned a 32-bit hash value from llseek()
to appease NFSv2, which can only handle a 32-bit cookie for seekdir()
and telldir().  However, this causes problems if there are 32-bit hash
collisions, since the NFSv2 server can get stuck resending the same
entries from the directory repeatedly.

Allow ext3 to return a full 64-bit hash (both major and minor) for
telldir to decrease the chance of hash collisions.

This patch does implement a new ext3_dir_llseek op, because with 64-bit
hashes, nfs will attempt to seek to a hash "offset" which is much
larger than ext3's s_maxbytes.  So for dx dirs, we call
generic_file_llseek_size() with the appropriate max hash value as the
maximum seekable size.  Otherwise we just pass through to
generic_file_llseek().

Patch-updated-by: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
Patch-updated-by: Eric Sandeen <sandeen@redhat.com>
(blame us if something is not correct)

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>