cinder-kilo-rbd-delete-snapshot.patch

diff --git a/cinder/volume/drivers/rbd.py b/cinder/volume/drivers/rbd.py
index 7dae2ec..f1d4d85 100644
--- a/cinder/volume/drivers/rbd.py
+++ b/cinder/volume/drivers/rbd.py
@@ -710,9 +710,27 @@ class RBDDriver(driver.VolumeDriver):
         with RBDVolumeProxy(self, volume_name) as volume:
             try:
                 volume.unprotect_snap(snap_name)
+            except self.rbd.InvalidArgument:
+                LOG.info(_LI("Unable to unprotect snapshot %s. InvalidArgument"), snap_name)
+            except self.rbd.ImageNotFound:
+                LOG.info(_LI("Unable to unprotect snapshot %s. ImageNotFound"), snap_name)
             except self.rbd.ImageBusy:
+                children_list = self._get_children_info(volume, snap_name)
+
+                if children_list:
+                    for (pool, image) in children_list:
+                        LOG.info(_LI('Image %(pool)s/%(image)s is dependent '
+                                     'on the snapshot %(snap)s.'),
+                                 {'pool': pool,
+                                  'image': image,
+                                  'snap': snap_name})
+
                 raise exception.SnapshotIsBusy(snapshot_name=snap_name)
-            volume.remove_snap(snap_name)
+            try:
+                volume.remove_snap(snap_name)
+            except self.rbd.ImageNotFound:
+                LOG.info(_LI("Snapshot %s does not exist in backend."),
+                         snap_name)

     def retype(self, context, volume, new_type, diff, host):
         """Retypes a volume, allows QoS change only."""