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dm thin metadata: use pool locking at end of dm_pool_metadata_close 

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: 873f258bec ("dm thin metadata: do not write metadata if no changes occurred")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mike Snitzer 2020-01-13 11:18:51 -05:00
parent aa9509209c
commit 44d8ebf436
1 changed files with 6 additions and 4 deletions
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10
drivers/md/dm-thin-metadata.c
View File

@ -387,16 +387,15 @@ static int subtree_equal(void *context, const void *value1_le, const void *value
* 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 dm_pool_metadata *pmd)
* 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_pool_metadata *pmd)
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_pool_metadata *pmd)
}
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_pool_metadata *pmd)
* 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;