Commit 44d8ebf4 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

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: 873f258b ("dm thin metadata: do not write metadata if no changes occurred")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent aa950920

drivers/md/dm-thin-metadata.c

+6 −4
Original line number Diff line number Diff line
@@ -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;

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