Commit c9c86379 authored Jan 20, 2025 by Qu Wenruo Committed by David Sterba Jan 23, 2025

btrfs: do not output error message if a qgroup has been already cleaned up



[BUG]
There is a bug report that btrfs outputs the following error message:

  BTRFS info (device nvme0n1p2): qgroup scan completed (inconsistency flag cleared)
  BTRFS warning (device nvme0n1p2): failed to cleanup qgroup 0/1179: -2

[CAUSE]
The error itself is pretty harmless, and the end user should ignore it.

When a subvolume is fully dropped, btrfs will call
btrfs_qgroup_cleanup_dropped_subvolume() to delete the qgroup.

However if a qgroup rescan happened before a subvolume fully dropped,
qgroup for that subvolume will not be re-created, as rescan will only
create new qgroup if there is a BTRFS_ROOT_REF_KEY found.

But before we drop a subvolume, the subvolume is unlinked thus there is no
BTRFS_ROOT_REF_KEY.

In that case, btrfs_remove_qgroup() will fail with -ENOENT and trigger
the above error message.

[FIX]
Just ignore -ENOENT error from btrfs_remove_qgroup() inside
btrfs_qgroup_cleanup_dropped_subvolume().

Reported-by: John Shand <jshand2013@gmail.com>
Link: https://bugzilla.suse.com/show_bug.cgi?id=1236056


Fixes: 839d6ea4 ("btrfs: automatically remove the subvolume qgroup")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

parent 0d85f5c2

fs/btrfs/qgroup.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -1897,8 +1897,11 @@ int btrfs_qgroup_cleanup_dropped_subvolume(struct btrfs_fs_info *fs_info, u64 su
		/*
		* It's squota and the subvolume still has numbers needed for future
		* accounting, in this case we can not delete it. Just skip it.
		*
		* Or the qgroup is already removed by a qgroup rescan. For both cases we're
		* safe to ignore them.
		*/
		if (ret == -EBUSY)
		if (ret == -EBUSY \|\| ret == -ENOENT)
		ret = 0;
		return ret;
		}