Fix volume_glance_metadata deletion (backport)

Backport patch https://review.openstack.org/#/c/41768/ and
its dependency: https://review.openstack.org/#/c/41601/
(no snapshot handling exception, for this is not trivial
due to specific havana changes)

If volume_glance_metadata does not exist for a certain volume,
it returns an exception and does not delete volume from db.
Avoid deleting it if it does not exist.

Fixes bug: 1209367

Change-Id: Icb34c90b13aac1e92b4645c3016127a2d4b8af6f

cinder/db/sqlalchemy/api.py

@@ -1610,9 +1610,15 @@ def volume_glance_metadata_get(context, volume_id, session=None):
     if not session:
         session = get_session()
 
-    return session.query(models.VolumeGlanceMetadata).\
+    rows = session.query(models.VolumeGlanceMetadata).\
         filter_by(volume_id=volume_id).\
-        filter_by(deleted=False).all()
+        filter_by(deleted=False).\
+        all()
+
+    if not rows:
+        raise exception.GlanceMetadataNotFound(id=volume_id)
+
+    return rows
 
 
 @require_context

cinder/exception.py

@@ -561,6 +561,10 @@ class GlanceMetadataExists(Invalid):
                 " exists for volume id %(volume_id)s")
 
 
+class GlanceMetadataNotFound(NotFound):
+    message = _("Glance metadata for volume/snapshot %(id)s cannot be found.")
+
+
 class ImageCopyFailure(Invalid):
     message = _("Failed to copy image to volume: %(reason)s")
 

cinder/tests/test_volume_glance_metadata.py

@@ -92,11 +92,8 @@ def test_vol_delete_glance_metadata(self):
         vol_metadata = db.volume_glance_metadata_create(ctxt, 1, 'key1',
                                                         'value1')
         db.volume_glance_metadata_delete_by_volume(ctxt, 1)
-        metadata = db.volume_glance_metadata_get(ctxt, 1)
-        self.assertEqual(len(metadata), 0)
-        db.volume_glance_metadata_delete_by_volume(ctxt, 1)
-        metadata = db.volume_glance_metadata_get(ctxt, 1)
-        self.assertEqual(len(metadata), 0)
+        self.assertRaises(exception.GlanceMetadataNotFound,
+                          db.volume_glance_metadata_get, ctxt, 1)
 
     def test_vol_glance_metadata_copy_to_snapshot(self):
         ctxt = context.get_admin_context()
@@ -120,10 +117,9 @@ def test_vol_glance_metadata_copy_to_volume(self):
         db.volume_create(ctxt, {'id': 100, 'source_volid': 1})
         vol_meta = db.volume_glance_metadata_create(ctxt, 1, 'key1',
                                                     'value1')
-        db.volume_glance_metadata_copy_from_volume_to_volume(ctxt, 100, 1)
+        db.volume_glance_metadata_copy_from_volume_to_volume(ctxt, 1, 100)
 
-        expected_meta = {'id': '100',
-                         'key': 'key1',
+        expected_meta = {'key': 'key1',
                          'value': 'value1'}
 
         for meta in db.volume_glance_metadata_get(ctxt, 100):

cinder/volume/manager.py

@@ -442,7 +442,15 @@ def delete_volume(self, context, volume_id):
             reservations = None
             LOG.exception(_("Failed to update usages deleting volume"))
 
-        self.db.volume_glance_metadata_delete_by_volume(context, volume_id)
+        # Delete glance metadata if it exists
+        try:
+            self.db.volume_glance_metadata_delete_by_volume(context, volume_id)
+            LOG.debug(_("volume %s: glance metadata deleted"),
+                      volume_ref['id'])
+        except exception.GlanceMetadataNotFound:
+            LOG.debug(_("no glance metadata found for volume %s"),
+                      volume_ref['id'])
+
         self.db.volume_destroy(context, volume_id)
         LOG.info(_("volume %s: deleted successfully"), volume_ref['name'])
         self._notify_about_volume_usage(context, volume_ref, "delete.end")
@@ -476,9 +484,16 @@ def create_snapshot(self, context, volume_id, snapshot_id):
         self.db.snapshot_update(context,
                                 snapshot_ref['id'], {'status': 'available',
                                                      'progress': '100%'})
-        self.db.volume_glance_metadata_copy_to_snapshot(context,
-                                                        snapshot_ref['id'],
-                                                        volume_id)
+        # only shows the trace for the exception
+        try:
+            self.db.volume_glance_metadata_copy_to_snapshot(
+                            context, snapshot_ref['id'], volume_id)
+        except exception.CinderException as ex:
+            LOG.exception(_("Failed updating %(snapshot_id)s"
+                            " metadata using the provided volumes"
+                            " %(volume_id)s metadata") %
+                          {'volume_id': volume_id,
+                           'snapshot_id': snapshot_id})
         LOG.info(_("snapshot %s: created successfully"), snapshot_ref['name'])
         return snapshot_id