Description of problem:
"ceph fs subvolumegroup ls cephfs" shows "_nogroup"

Version-Release number of selected component (if applicable):
ceph Version 16.2.8-31.el8cp


How reproducible:
After creating cluster,, try to create numbers of subvolumes in a subvolumegroup. After kernel mounting it, clean up the subvolume and subvolume group .

Steps to Reproduce:
1. Create subvolumegroup
2. Create a few subvolumes in the subvolumegroup
3. Kernel mount it
4. Run some IOs in the mount dir
5. Remove the subvolumes
6. Revmoce the subvolumegroup
7. Check if subvolumegroup ls shows "_nogroup"

Actual results:
[cephuser@ceph-julpark-wjyw1m-node7 ~]$ ceph fs subvolumegroup ls cephfs
[
    {
        "name": "_nogroup"
    }
]

Expected results:
[]

Additional info:

[cephuser@ceph-julpark-wjyw1m-node7 ~]$ ceph fs subvolumegroup ls cephfs
[]
(After the reproducible steps)
[cephuser@ceph-julpark-wjyw1m-node7 ~]$ ceph fs subvolumegroup ls cephfs
[
    {
        "name": "_nogroup"
    }
]