[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 detects 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@xxxxxxxxxxxxxxx # 6.1+
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
---
For the proper fix, we need to change the behavior of clear_cache and v1
cache switch.
For pure clear_cache without switch cache version, we should allow
rebuilding v2 cache without fully disable v2 cache.
---
fs/btrfs/super.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 581845bc206a..eefae0318d4f 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -826,7 +826,12 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
!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);
--
2.39.2
