Merge tag 'dm-4.4-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:
 "Five stable fixes:

   - Two DM btree bufio buffer leak fixes that resolve reported BUG_ONs
     during DM thinp metadata close's dm_bufio_client_destroy().

   - A DM thinp range discard fix to handle discarding a partially
     mapped range.

   - A DM thinp metadata snapshot fix to make sure the btree roots saved
     in the metadata snapshot are the most current.

   - A DM space map metadata refcounting fix that improves both DM thinp
     and DM cache metadata"

* tag 'dm-4.4-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm btree: fix bufio buffer leaks in dm_btree_del() error path
  dm space map metadata: fix ref counting bug when bootstrapping a new space map
  dm thin metadata: fix bug when taking a metadata snapshot
  dm thin metadata: fix bug in dm_thin_remove_range()
  dm btree: fix leak of bufio-backed block in btree_split_sibling error path