Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm

* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm:
  dm snapshot: allow chunk size to be less than page size
  dm snapshot: use unsigned integer chunk size
  dm snapshot: lock snapshot while supplying status
  dm exception store: fix failed set_chunk_size error path
  dm snapshot: require non zero chunk size by end of ctr
  dm: dec_pending needs locking to save error value
  dm: add missing del_gendisk to alloc_dev error path
  dm log: userspace fix incorrect luid cast in userspace_ctr
  dm snapshot: free exception store on init failure
  dm snapshot: sort by chunk size to fix race