Commit cb3806ec authored Nov 27, 2012 by Stefan Behrens Committed by Chris Mason Dec 16, 2012

Btrfs: fix race in check-integrity caused by usage of bitfield



The structure member mirror_num is modified concurrently to the
structure member is_iodone. This doesn't require any locking by
design, unless everything is stored in the same 32 bits of a
bit field. This was the case and xfstest 284 was able to
trigger false warnings from the checker code. This patch
seperates the bits and fixes the race.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

parent b66f00da

fs/btrfs/check-integrity.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -137,7 +137,7 @@ struct btrfsic_block {
		unsigned int never_written:1; /* block was added because it was
		* referenced, not because it was
		* written */
		unsigned int mirror_num:2; /* large enough to hold
		unsigned int mirror_num; /* large enough to hold
		* BTRFS_SUPER_MIRROR_MAX */
		struct btrfsic_dev_state *dev_state;
		u64 dev_bytenr; /* key, physical byte num on disk */