Pull device mapper fixes from Mike Snitzer:
 "Two stable fixes for dm-cache and one 3.19 DM core fix:

   - fix potential for dm-cache metadata corruption via stale metadata
     buffers being used when switching an inactive cache table to
     active; this could occur due to each table having it's own bufio
     client rather than sharing the client between tables.

   - fix dm-cache target to properly account for discard IO while
     suspending otherwise IO quiescing could complete prematurely.

   - fix DM core's handling of multiple internal suspends by maintaining
     an 'internal_suspend_count' and only resuming the device when this
     count drops to zero"

* tag 'dm-3.19-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: fix handling of multiple internal suspends
  dm cache: fix problematic dual use of a single migration count variable
  dm cache: share cache-metadata object across inactive and active DM tables