Commit ecf99cde authored Jul 02, 2019 by Mike Snitzer Committed by Greg Kroah-Hartman Sep 16, 2019

dm thin metadata: check if in fail_io mode when setting needs_check



[ Upstream commit 54fa16ee532705985e6c946da455856f18f63ee1 ]

Check if in fail_io mode at start of dm_pool_metadata_set_needs_check().
Otherwise dm_pool_metadata_set_needs_check()'s superblock_lock() can
crash in dm_bm_write_lock() while accessing the block manager object
that was previously destroyed as part of a failed
dm_pool_abort_metadata() that ultimately set fail_io to begin with.

Also, update DMERR() message to more accurately describe
superblock_lock() failure.

Cc: stable@vger.kernel.org
Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 5e9a2ce6

drivers/md/dm-thin-metadata.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -2001,16 +2001,19 @@ int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd,

		int dm_pool_metadata_set_needs_check(struct dm_pool_metadata *pmd)
		{
		int r;
		int r = -EINVAL;
		struct dm_block *sblock;
		struct thin_disk_superblock *disk_super;

		down_write(&pmd->root_lock);
		if (pmd->fail_io)
		goto out;

		pmd->flags \|= THIN_METADATA_NEEDS_CHECK_FLAG;

		r = superblock_lock(pmd, &sblock);
		if (r) {
		DMERR("couldn't read superblock");
		DMERR("couldn't lock superblock");
		goto out;
		}