From a96295965b600f2dc6ad661c4803c86e87db3d7b Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Mon, 18 May 2015 19:11:40 +0100 Subject: Btrfs: fix racy system chunk allocation when setting block group ro If while setting a block group read-only we end up allocating a system chunk, through check_system_chunk(), we were not doing it while holding the chunk mutex which is a problem if a concurrent chunk allocation is happening, through do_chunk_alloc(), as it means both block groups can end up using the same logical addresses and physical regions in the device(s). So make sure we hold the chunk mutex. Cc: stable@vger.kernel.org # 4.0+ Fixes: 2f0810880f08 ("btrfs: delete chunk allocation attemp when setting block group ro") Signed-off-by: Filipe Manana Signed-off-by: Chris Mason --- fs/btrfs/volumes.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/btrfs/volumes.c') diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 96aebf3bcd5b..174f5e1e00ab 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4625,6 +4625,7 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans, { u64 chunk_offset; + ASSERT(mutex_is_locked(&extent_root->fs_info->chunk_mutex)); chunk_offset = find_next_chunk(extent_root->fs_info); return __btrfs_alloc_chunk(trans, extent_root, chunk_offset, type); } -- cgit v1.2.3-59-g8ed1b