. Fix dm-cache corruption caused by discard_block_size >
cache_block_size
. Fix a lock-inversion detected by LOCKDEP in dm-cache
. Fix a dangling bio bug in the dm-thinp target's process_deferred_bios
error path
. Fix corruption due to non-atomic transaction commit which allowed a
metadata superblock to be written before all other metadata was
successfully written -- this is common to all targets that use the
persistent-data library's transaction manager (dm-thinp, dm-cache and
dm-era).
. Various small cleanups in the DM core
. Add the dm-era target which is useful for keeping track of which
blocks were written within a user defined period of time called an
'era'. Use cases include tracking changed blocks for backup software,
and partially invalidating the contents of a cache to restore cache
coherency after rolling back a vendor snapshot.
. Improve the on-disk layout of multithreaded writes to the dm-thin-pool
by splitting the pool's deferred bio list to be a per-thin device list
and then sorting that list using an rb_tree. The subsequent read
throughput of the data written via multiple threads improved by ~70%.
. Simplify the multipath target's handling of queuing IO by pushing
requests back to the request queue rather than queueing the IO
internally.
dm cache: fix a lock-inversion
When suspending a cache the policy is walked and the individual policy
hints written to the metadata via sync_metadata(). This led to this
lock order:
policy->lock
cache_metadata->root_lock
When loading the cache target the policy is populated while the metadata
lock is held:
cache_metadata->root_lock
policy->lock
Fix this potential lock-inversion (ABBA) deadlock in sync_metadata() by
ensuring the cache_metadata root_lock is held whilst all the hints are
written, rather than being repeatedly locked while policy->lock is held
(as was the case with each callout that policy_walk_mappings() made to
the old save_hint() method).
Found by turning on the CONFIG_PROVE_LOCKING ("Lock debugging: prove
locking correctness") build option. However, it is not clear how the
LOCKDEP reported paths can lead to a deadlock since the two paths,
suspending a target and loading a target, never occur at the same time.
But that doesn't mean the same lock-inversion couldn't have occurred
elsewhere.
Reported-by: Marian Csontos <mcsontos@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
3 files changed
