Creating image-volume cache on NFS backend fails

snapshot.id doesn't have `tmp-snap` in it as id
is not passed as a option while creating snapshot
object. This should be change to
`snapshot.display_name` at same location
Also includes regression and NITs from other
patches
(I33da9c65ef56b3e4967170e3a0fb25f12e067876)
(Ia620043904f4f31a81bc8463fb36476a149f9808)
(Id0b4981be5bf4e79aedcdad2258fc64aad8eeb72)

Closes-Bug: #1875570
Change-Id: I66da0212a61d778fe9795d382b3af5b225a8aa54
(cherry picked from commit f68a64540f)
(cherry picked from commit 193f3e97ce)

cinder/tests/unit/volume/drivers/test_remotefs.py

@@ -256,10 +256,13 @@ class RemoteFsSnapDriverTestCase(test.TestCase):
                  mock.call(*command3, run_as_root=True)]
         self._driver._execute.assert_has_calls(calls)
 
-    def _test_create_snapshot(self, volume_in_use=False, tmp_snap=False):
+    def _test_create_snapshot(self, volume_in_use=False, tmp_snap=False,
+                              display_name=None):
         fake_snapshot_info = {}
         fake_snapshot_file_name = os.path.basename(self._fake_snapshot_path)
 
+        snapshot = self._fake_snapshot
+        snapshot.display_name = display_name
         self._driver._local_path_volume_info = mock.Mock(
             return_value=mock.sentinel.fake_info_path)
         self._driver._read_info_file = mock.Mock(
@@ -278,16 +281,15 @@ class RemoteFsSnapDriverTestCase(test.TestCase):
             self._fake_snapshot.id: fake_snapshot_file_name
         }
         exp_acceptable_states = ['available', 'in-use', 'backing-up']
-        if tmp_snap:
+        if display_name and display_name.startswith('tmp-snap-'):
             exp_acceptable_states.append('downloading')
-            self._fake_snapshot.id = 'tmp-snap-%s' % self._fake_snapshot.id
+            self._fake_snapshot.volume.status = 'downloading'
 
         if volume_in_use:
             self._fake_snapshot.volume.status = 'backing-up'
             self._fake_snapshot.volume.attach_status = 'attached'
             expected_method_called = '_create_snapshot_online'
         else:
-            self._fake_snapshot.volume.status = 'available'
             expected_method_called = '_do_create_snapshot'
 
         self._driver._create_snapshot(self._fake_snapshot)
@@ -315,6 +317,10 @@ class RemoteFsSnapDriverTestCase(test.TestCase):
                           self._driver._create_snapshot,
                           self._fake_snapshot)
 
+    @ddt.data(None, 'test', 'tmp-snap-404f-404')
+    def test_create_snapshot_names(self, display_name):
+        self._test_create_snapshot(display_name=display_name)
+
     @mock.patch('cinder.db.snapshot_get')
     @mock.patch('time.sleep')
     def test_create_snapshot_online_with_concurrent_delete(

cinder/volume/drivers/remotefs.py

@@ -1439,7 +1439,8 @@ class RemoteFSSnapDriverBase(RemoteFSDriver):
         status = snapshot.volume.status
 
         acceptable_states = ['available', 'in-use', 'backing-up']
-        if snapshot.id.startswith('tmp-snap-'):
+        if (snapshot.display_name and
+                snapshot.display_name.startswith('tmp-snap-')):
             # This is an internal volume snapshot. In order to support
             # image caching, we'll allow creating/deleting such snapshots
             # while having volumes in 'downloading' state.

releasenotes/notes/bug-1875570-nfs-image-volume-cache-c45e840a6ec2a702.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    `Bug #1875570 <https://bugs.launchpad.net/cinder/+bug/1875570>`_:
+    Fixed issue with NFS backend where the image-volume cache was
+    never used to create a volume, even when the cache was enabled.