From: Qu Wenruo wqu@suse.com
commit 64b5d5b2852661284ccbb038c697562cc56231bf upstream.
[BUG] With block-group-tree feature enabled, mounting it with clear_cache would cause the following transaction abort at mount or remount:
BTRFS info (device dm-4): force clearing of disk cache BTRFS info (device dm-4): using free space tree BTRFS info (device dm-4): auto enabling async discard BTRFS info (device dm-4): clearing free space tree BTRFS info (device dm-4): clearing compat-ro feature flag for FREE_SPACE_TREE (0x1) BTRFS info (device dm-4): clearing compat-ro feature flag for FREE_SPACE_TREE_VALID (0x2) BTRFS error (device dm-4): block-group-tree feature requires fres-space-tree and no-holes BTRFS error (device dm-4): super block corruption detected before writing it to disk BTRFS: error (device dm-4) in write_all_supers:4288: errno=-117 Filesystem corrupted (unexpected superblock corruption detected) BTRFS warning (device dm-4: state E): Skipping commit of aborted transaction.
[CAUSE] For block-group-tree feature, we have an artificial dependency on free-space-tree.
This means if we detect block-group-tree without v2 cache, we consider it a corruption and cause the problem.
For clear_cache mount option, it would temporary disable v2 cache, then re-enable it.
But unfortunately for that temporary v2 cache disabled status, we refuse to write a superblock with bg tree only flag, thus leads to the above transaction abortion.
[FIX] For now, just reject clear_cache and v1 cache mount option for block group tree. So now we got a graceful rejection other than a transaction abort:
BTRFS info (device dm-4): force clearing of disk cache BTRFS error (device dm-4): cannot disable free space tree with block-group-tree feature BTRFS error (device dm-4): open_ctree failed
CC: stable@vger.kernel.org # 6.1+ Signed-off-by: Qu Wenruo wqu@suse.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/super.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1136,7 +1136,12 @@ out: !btrfs_test_opt(info, CLEAR_CACHE)) { btrfs_err(info, "cannot disable free space tree"); ret = -EINVAL; - + } + if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) && + (btrfs_test_opt(info, CLEAR_CACHE) || + !btrfs_test_opt(info, FREE_SPACE_TREE))) { + btrfs_err(info, "cannot disable free space tree with block-group-tree feature"); + ret = -EINVAL; } if (!ret) ret = btrfs_check_mountopts_zoned(info);