CephFS doesn't support subvolume group snapshots

[Goutham Pacha Ravi]

Description
===========
The CephFS driver had the ability to create and delete share group snapshots since Mitaka release. From Ceph Nautilus, there's growing support for a ceph volume interface which can be used via the "ceph fs <subcommand>" command. The manila driver in Wallaby started using this interface and the group snapshot creation is currently done via the "ceph fs subvolumegroup snapshot create" command [1]. This feature is however turned off in CephFS now [2].

Steps to reproduce
==================

A chronological list of steps which will help reproduce the issue you hit:
* Create share group
* Create one or more shares in the group
* Create share group snapshot

Expected result
===============

Actual result
=============
Share group snapshot is set to "error". There's a traceback in the manila-share logs: http://paste.openstack.org/show/804612/

Environment
===========
1. Wallaby release of OpenStack Manila, Native CephFS

[1] https://docs.ceph.com/en/latest/cephfs/fs-volumes/#fs-subvolume-groups
[2] https://github.com/ceph/ceph/blob/9541a976055bdb5ee457da7a4b0a633880faeb2b/src/pybind/mgr/volumes/fs/volume.py#L654-L669

[Vida Haririan (vhariria)]

Additional comments http://eavesdrop.openstack.org/meetings/manila/2021/manila.2021-04-29-15.00.log.html

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/manila/+/801336

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/manila/+/801336
Committed: https://opendev.org/openstack/manila/commit/cf4af616383fe416a11732d4247e48bdb6941f16
Submitter: "Zuul (22348)"
Branch: master

commit cf4af616383fe416a11732d4247e48bdb6941f16
Author: Victoria Martinez de la Cruz <email address hidden>
Date: Mon Jul 19 14:40:57 2021 +0000

    Deprecate create snapshot from share group in CephFS

    Deprecate the create snapshot from share group feature
    in CephFS drivers (both Native and NFS Ganesha).

    This needs to be done since the subvolume group snapshot
    feature is no longer supported in mainline CephFS, meaning that,
    if we leave the call in place, an exception will be raised
    from the backend and lead to an error status for the attempted
    snapshot from share group.

    Existing group snapshots can still be listed and deleted, so these
    operations stay the same.

    Closes-Bug: #1925332
    Change-Id: I49efb7042d38257416875f40c03923e974b2eb8e

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/manila 13.0.0.0rc1 release candidate.