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

doc/source/admin/cephfs_driver.rst

@@ -41,7 +41,7 @@ Supported Operations
 
 The following operations are supported with CephFS backend:
 
-- Create/delete share
+- Create, delete, update and list share
 - Allow/deny access to share
 
   * Only ``cephx`` access type is supported for CephFS native protocol.
@@ -49,10 +49,12 @@ The following operations are supported with CephFS backend:
   * ``read-only`` and ``read-write`` access levels are supported.
 
 - Extend/shrink share
-- Create/delete snapshot
-- Create/delete share groups
-- Create/delete share group snapshots
+- Create, delete, update and list snapshot
+- Create, delete, update and list share groups
+- Delete and list share group snapshots
 
+.. important:: Share group snapshot creation is no longer supported in mainline
+               CephFS. This feature has been removed from manila W release.
 
 Prerequisites
 ~~~~~~~~~~~~~

manila/share/drivers/cephfs/driver.py

@@ -601,7 +601,7 @@ class CephFSDriver(driver.ExecuteMixin, driver.GaneshaMixin,
         rados_command(self.rados_client, "fs subvolumegroup create", argdict)
 
     def delete_share_group(self, context, sg_dict, share_server=None):
-        # create a FS group
+        # delete a FS group
         LOG.debug("[%(be)s]: delete_share_group: share_group=%(id)s.",
                   {"be": self.backend_name, "id": sg_dict['id']})
 
@@ -641,16 +641,10 @@ class CephFSDriver(driver.ExecuteMixin, driver.GaneshaMixin,
                   {"be": self.backend_name, "id": snap_dict['share_group_id'],
                    "sn": snap_dict["id"]})
 
-        argdict = {
-            "vol_name": self.volname,
-            "group_name": snap_dict["share_group_id"],
-            "snap_name": snap_dict["id"]
-        }
-
-        rados_command(
-            self.rados_client, "fs subvolumegroup snapshot create", argdict)
-
-        return None, []
+        msg = _("Share group snapshot feature is no longer supported in "
+                "mainline CephFS (existing group snapshots can still be "
+                "listed and deleted).")
+        raise exception.ShareBackendException(msg=msg)
 
     def _get_clone_status(self, share):
         """Check the status of a newly cloned share."""

manila/tests/share/drivers/cephfs/test_driver.py

@@ -409,22 +409,15 @@ class CephFSDriverTestCase(test.TestCase):
             group_delete_prefix, group_delete_dict)
 
     def test_create_share_group_snapshot(self):
-        group_snapshot_create_prefix = "fs subvolumegroup snapshot create"
+        msg = ("Share group snapshot feature is no longer supported in "
+               "mainline CephFS (existing group snapshots can still be "
+               "listed and deleted).")
+        driver.rados_command.side_effect = exception.ShareBackendException(msg)
 
-        group_snapshot_create_dict = {
-            "vol_name": self._driver.volname,
-            "group_name": "sgid",
-            "snap_name": "snapid",
-        }
-
-        self._driver.create_share_group_snapshot(self._context, {
-            'share_group_id': 'sgid',
-            'id': 'snapid',
-        })
-
-        driver.rados_command.assert_called_once_with(
-            self._driver.rados_client,
-            group_snapshot_create_prefix, group_snapshot_create_dict)
+        self.assertRaises(exception.ShareBackendException,
+                          self._driver.create_share_group_snapshot,
+                          self._context, {'share_group_id': 'sgid',
+                                          'id': 'snapid'})
 
     def test_delete_share_group_snapshot(self):
         group_snapshot_delete_prefix = "fs subvolumegroup snapshot rm"

releasenotes/notes/bug-1871252-cephfs-doesnt-support-subvolume-group-snapshots-344efbb9ba74e05c.yaml

@@ -0,0 +1,8 @@
+---
+deprecations:
+  - |
+    Create share group snapshot feature is no longer supported
+    in manila CephFS drivers (both Native and NFS Ganesha) since
+    the subvolume group snapshot feature is no longer supported
+    in mainline CephFS (existing group snapshots can still
+    be listed and deleted).