From: David Sterba dsterba@suse.com
[ Upstream commit 7411055db5ce64f836aaffd422396af0075fdc99 ]
The unhandled case in btrfs_relocate_sys_chunks() loop is a corruption, as it could be caused only by two impossible conditions:
- at first the search key is set up to look for a chunk tree item, with offset -1, this is an inexact search and the key->offset will contain the correct offset upon a successful search, a valid chunk tree item cannot have an offset -1
- after first successful search, the found_key corresponds to a chunk item, the offset is decremented by 1 before the next loop, it's impossible to find a chunk item there due to alignment and size constraints
Reviewed-by: Josef Bacik josef@toxicpanda.com Reviewed-by: Anand Jain anand.jain@oracle.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/volumes.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index ceced5e56c5a9..30b5646b2c0de 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2948,7 +2948,17 @@ static int btrfs_relocate_sys_chunks(struct btrfs_fs_info *fs_info) mutex_unlock(&fs_info->delete_unused_bgs_mutex); goto error; } - BUG_ON(ret == 0); /* Corruption */ + if (ret == 0) { + /* + * On the first search we would find chunk tree with + * offset -1, which is not possible. On subsequent + * loops this would find an existing item on an invalid + * offset (one less than the previous one, wrong + * alignment and size). + */ + ret = -EUCLEAN; + goto error; + }
ret = btrfs_previous_item(chunk_root, path, key.objectid, key.type);