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: extend exception store functions
dm snapshot: split out exception store implementations
dm snapshot: rename struct exception_store
dm snapshot: separate out exception store interface
dm mpath: move trigger_event to system workqueue
dm: add name and uuid to sysfs
dm table: rework reference counting
dm: support barriers on simple devices
dm request: extend target interface
dm request: add caches
dm ioctl: allow dm_copy_name_and_uuid to return only one field
dm log: ensure log bitmap fits on log device
dm log: move region_size validation
dm log: avoid reinitialising io_req on every operation
dm: consolidate target deregistration error handling
dm raid1: fix error count
dm log: fix dm_io_client leak on error paths
dm snapshot: change yield to msleep
dm table: drop reference at unbind