btrfs: forbid creating subvol qgroups

Creating a qgroup 0/subvolid leads to various races and it isn't
helpful, because you can't specify a subvol id when creating a subvol,
so you can't be sure it will be the right one. Any requirements on the
automatic subvol can be gratified by using a higher level qgroup and the
inheritance parameters of subvol creation.

Fixes: cecbb533b5 ("btrfs: record simple quota deltas in delayed refs")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Boris Burkov 2024-01-10 17:51:26 -08:00 committed by David Sterba
parent f884a9f9e5
commit 0c309d66da

View File

@ -3806,6 +3806,11 @@ static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg)
goto out;
}
if (sa->create && is_fstree(sa->qgroupid)) {
ret = -EINVAL;
goto out;
}
trans = btrfs_join_transaction(root);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);