Hi,

I tried to configure qgroups on a btrfs filesystem but was really surprised that when you snapshot a subvolume, the snapshot will not be assigned to the qgroup the subvolume was in.

As an example consider the small terminal session in the attachment: I create a subvol A, assign it to qgroup 1/1 and set a limit of 5M on that qgroup. Then I write a file into A and eventually get "disk quota exceeded". Then I create a snapshot of A and call it B. B will not be assigned to 1/1 and writing a file into B confirms that no limits at all are imposed for B.

I feel like I must be missing something here. Considering that creating a snapshot does not require root privileges this would mean that any user can just circumvent any quota and therefore make them useless.

Is there a way to enforce quotas even when a user creates snapshots?


Moritz