btrfs: qgroup: do not leak -ENOENT from btrfs_remove_qgroup()

If btrfs_remove_qgroup() is called on a qgroup that only exists in the
rb-tree, then del_qgroup_item() will return -ENOENT, and we tolerate
that -ENOENT.

However if the to-be-deleted qgroup has no parent qgroups, the @ret will
not be updated, and will leak to user space.

It will make the ioctl() caller incorrectly assume the operation failed.

Fix it by resetting @ret to 0 after a successful or tolerated
del_qgroup_item() call, so the -ENOENT from del_qgroup_item() won't be
leaked.

Assisted-by: LLM (exposing this pre-existing problem)
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

0 files changed, 0 insertions, 0 deletions