From: Mike Snitzer snitzer@redhat.com
commit 44d8ebf436399a40fcd10dd31b29d37823d62fcc upstream.
Ensure that the pool is locked during calls to __commit_transaction and __destroy_persistent_data_objects. Just being consistent with locking, but reality is dm_pool_metadata_close is called once pool is being destroyed so access to pool shouldn't be contended.
Also, use pmd_write_lock_in_core rather than __pmd_write_lock in dm_pool_commit_metadata and rename __pmd_write_lock to pmd_write_lock_in_core -- there was no need for the alias.
In addition, verify that the pool is locked in __commit_transaction().
Fixes: 873f258becca ("dm thin metadata: do not write metadata if no changes occurred") Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/md/dm-thin-metadata.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -387,16 +387,15 @@ static int subtree_equal(void *context, * Variant that is used for in-core only changes or code that * shouldn't put the pool in service on its own (e.g. commit). */ -static inline void __pmd_write_lock(struct dm_pool_metadata *pmd) +static inline void pmd_write_lock_in_core(struct dm_pool_metadata *pmd) __acquires(pmd->root_lock) { down_write(&pmd->root_lock); } -#define pmd_write_lock_in_core(pmd) __pmd_write_lock((pmd))
static inline void pmd_write_lock(struct dm_pool_metadata *pmd) { - __pmd_write_lock(pmd); + pmd_write_lock_in_core(pmd); if (unlikely(!pmd->in_service)) pmd->in_service = true; } @@ -831,6 +830,7 @@ static int __commit_transaction(struct d * We need to know if the thin_disk_superblock exceeds a 512-byte sector. */ BUILD_BUG_ON(sizeof(struct thin_disk_superblock) > 512); + BUG_ON(!rwsem_is_locked(&pmd->root_lock));
if (unlikely(!pmd->in_service)) return 0; @@ -953,6 +953,7 @@ int dm_pool_metadata_close(struct dm_poo return -EBUSY; }
+ pmd_write_lock_in_core(pmd); if (!dm_bm_is_read_only(pmd->bm) && !pmd->fail_io) { r = __commit_transaction(pmd); if (r < 0) @@ -961,6 +962,7 @@ int dm_pool_metadata_close(struct dm_poo } if (!pmd->fail_io) __destroy_persistent_data_objects(pmd); + pmd_write_unlock(pmd);
kfree(pmd); return 0; @@ -1841,7 +1843,7 @@ int dm_pool_commit_metadata(struct dm_po * Care is taken to not have commit be what * triggers putting the thin-pool in-service. */ - __pmd_write_lock(pmd); + pmd_write_lock_in_core(pmd); if (pmd->fail_io) goto out;