Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 bugfixes from Ted Ts'o:
 "More bug fixes for ext4 -- most importantly, a fix for a bug
  introduced in 3.15 that can end up triggering a file system corruption
  error after a journal replay.

  It shouldn't lead to any actual data corruption, but it is scary and
  can force file systems to be remounted read-only, etc"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: fix potential null pointer dereference in ext4_free_inode
  ext4: fix a potential deadlock in __ext4_es_shrink()
  ext4: revert commit which was causing fs corruption after journal replays
  ext4: disable synchronous transaction batching if max_batch_time==0
  ext4: clarify ext4_error message in ext4_mb_generate_buddy_error()
  ext4: clarify error count warning messages
  ext4: fix unjournalled bg descriptor while initializing inode bitmap