Merge tag 'dm-3.6-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm

Pull device-mapper updates from Alasdair G Kergon:
- Flip the thin target into new read-only or failed modes if errors
  are detected;
- Handle chunk sizes that are not powers of two in the snapshot and
  thin targets;
- Provide a way for userspace to avoid replacing an already-loaded
  multipath hardware handler while booting;
- Reduce dm_thin_endio_hook slab size to avoid allocation failures;
- Numerous small changes and cleanups to the code.

* tag 'dm-3.6-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm: (63 commits)
  dm thin: commit before gathering status
  dm thin: add read only and fail io modes
  dm thin metadata: introduce dm_pool_abort_metadata
  dm thin metadata: introduce dm_pool_metadata_set_read_only
  dm persistent data: introduce dm_bm_set_read_only
  dm thin: reduce number of metadata commits
  dm thin metadata: add dm_thin_changed_this_transaction
  dm thin metadata: add format option to dm_pool_metadata_open
  dm thin metadata: tidy up open and format error paths
  dm thin metadata: only check incompat features on open
  dm thin metadata: remove duplicate pmd initialisation
  dm thin metadata: remove create parameter from __create_persistent_data_objects
  dm thin metadata: move __superblock_all_zeroes to __open_or_format_metadata
  dm thin metadata: remove nr_blocks arg from __create_persistent_data_objects
  dm thin metadata: split __open or format metadata
  dm thin metadata: use struct dm_pool_metadata members in __open_or_format_metadata
  dm thin metadata: zero unused superblock uuid
  dm thin metadata: lift __begin_transaction out of __write_initial_superblock
  dm thin metadata: move dm_commit_pool_metadata into __write_initial_superblock
  dm thin metadata: factor out __write_initial_superblock
  ...