From cb3806ec88a7e1e9d1fbde34cbc0bf153b7e7c3f Mon Sep 17 00:00:00 2001 From: Stefan Behrens Date: Tue, 27 Nov 2012 16:10:21 +0000 Subject: [PATCH] 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 Signed-off-by: Chris Mason --- fs/btrfs/check-integrity.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c index badc6f141b6f..11d47bfb62b4 100644 --- a/fs/btrfs/check-integrity.c +++ b/fs/btrfs/check-integrity.c @@ -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 */