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Commit 6096d91a authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm space map metadata: fix occasional leak of a metadata block on resize 



The metadata space map has a simplified 'bootstrap' mode that is
operational when extending the space maps.  Whilst in this mode it's
possible for some refcount decrement operations to become queued (eg, as
a result of shadowing one of the bitmap indexes).  These decrements were
not being applied when switching out of bootstrap mode.

The effect of this bug was the leaking of a 4k metadata block.  This is
detected by the latest version of thin_check as a non fatal error.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
parent b1f11aff

drivers/md/persistent-data/dm-space-map-metadata.c

+35 −15
Original line number Original line Diff line number Diff line
@@ -204,19 +204,10 @@ static void in(struct sm_metadata *smm) 
	smm->recursion_count++;

	smm->recursion_count++;

}

}





static int out(struct sm_metadata *smm)

static int apply_bops(struct sm_metadata *smm)

{

{

	int r = 0;

	int r = 0;





	/*

	 * If we're not recursing then very bad things are happening.

	 */

	if (!smm->recursion_count) {

		DMERR("lost track of recursion depth");

		return -ENOMEM;

	}



	if (smm->recursion_count == 1) {

	while (!brb_empty(&smm->uncommitted)) {

	while (!brb_empty(&smm->uncommitted)) {

		struct block_op bop;

		struct block_op bop;
@@ -230,8 +221,25 @@ static int out(struct sm_metadata *smm) 
		if (r)

		if (r)

			break;

			break;

	}

	}



	return r;

}



static int out(struct sm_metadata *smm)

{

	int r = 0;



	/*

	 * If we're not recursing then very bad things are happening.

	 */

	if (!smm->recursion_count) {

		DMERR("lost track of recursion depth");

		return -ENOMEM;

	}

	}





	if (smm->recursion_count == 1)

		apply_bops(smm);



	smm->recursion_count--;

	smm->recursion_count--;





	return r;

	return r;
@@ -704,6 +712,12 @@ static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks) 
		}

		}

		old_len = smm->begin;

		old_len = smm->begin;





		r = apply_bops(smm);

		if (r) {

			DMERR("%s: apply_bops failed", __func__);

			goto out;

		}



		r = sm_ll_commit(&smm->ll);

		r = sm_ll_commit(&smm->ll);

		if (r)

		if (r)

			goto out;

			goto out;
@@ -773,6 +787,12 @@ int dm_sm_metadata_create(struct dm_space_map *sm, 
	if (r)

	if (r)

		return r;

		return r;





	r = apply_bops(smm);

	if (r) {

		DMERR("%s: apply_bops failed", __func__);

		return r;

	}



	return sm_metadata_commit(sm);

	return sm_metadata_commit(sm);

}

}