GlusterFS: Use correct base argument when deleting attached snaps

When deleting the most recent snapshot, the 'file_to_merge' field
which translates into the base= field for libvirt's blockRebase
call in Nova must be set depending on whether other snapshots exist.

If there are no other snapshots, base = None, which results in
libvirt clearing the qcow2 backing file pointer for the active
disk image.

If there are other snapshots, pass the parent of the file being
deleted as the new base file.  The snapshot info pointer for the
prior base file must also be updated in this case.

Closes-Bug: #1262880
Change-Id: If7bc8259b031d0406346caafb8f688e65a38dba6

diff --git a/cinder/tests/test_glusterfs.py b/cinder/tests/test_glusterfs.py
index 23874a9b4cdc40e1b067d11ba92e86ba158c398c..69a616e0921896fe1f29ae5151670e6914c2d41b 100644 (file)
--- a/cinder/tests/test_glusterfs.py
+++ b/cinder/tests/test_glusterfs.py
@@ -1175,7 +1175,7 @@ class GlusterFsDriverTestCase(test.TestCase):
                           snap_ref)
 
     def test_delete_snapshot_online_1(self):
-        """Delete the newest snapshot."""
+        """Delete the newest snapshot, with only one snap present."""
         (mox, drv) = self._mox, self._driver
 
         volume = self._simple_volume()
@@ -1226,15 +1226,25 @@ class GlusterFsDriverTestCase(test.TestCase):
         backing file: %s
         """ % (snap_file, volume_file)
         img_info = imageutils.QemuImgInfo(qemu_img_info_output)
+
+        vol_qemu_img_info_output = """image: %s
+        file format: raw
+        virtual size: 1.0G (1073741824 bytes)
+        disk size: 173K
+        """ % volume_file
+        volume_img_info = imageutils.QemuImgInfo(vol_qemu_img_info_output)
+
         image_utils.qemu_img_info(snap_path).AndReturn(img_info)
 
+        image_utils.qemu_img_info(volume_path).AndReturn(volume_img_info)
+
         drv._read_info_file(info_path, empty_if_missing=True).\
             AndReturn(snap_info)
 
         delete_info = {
             'type': 'qcow2',
             'merge_target_file': None,
-            'file_to_merge': volume_file,
+            'file_to_merge': None,
             'volume_id': self.VOLUME_UUID
         }
 
@@ -1265,7 +1275,7 @@ class GlusterFsDriverTestCase(test.TestCase):
         drv.delete_snapshot(snap_ref)
 
     def test_delete_snapshot_online_2(self):
-        """Delete the middle snapshot."""
+        """Delete the middle of 3 snapshots."""
         (mox, drv) = self._mox, self._driver
 
         volume = self._simple_volume()
@@ -1320,8 +1330,17 @@ class GlusterFsDriverTestCase(test.TestCase):
         """ % (snap_file, volume_file)
         img_info = imageutils.QemuImgInfo(qemu_img_info_output)
 
+        vol_qemu_img_info_output = """image: %s
+        file format: raw
+        virtual size: 1.0G (1073741824 bytes)
+        disk size: 173K
+        """ % volume_file
+        volume_img_info = imageutils.QemuImgInfo(vol_qemu_img_info_output)
+
         image_utils.qemu_img_info(snap_path).AndReturn(img_info)
 
+        image_utils.qemu_img_info(volume_path).AndReturn(volume_img_info)
+
         drv._read_info_file(info_path, empty_if_missing=True).\
             AndReturn(snap_info)
 

diff --git a/cinder/volume/drivers/glusterfs.py b/cinder/volume/drivers/glusterfs.py
index 9279692169ceca49aa721598ca60c169070f39b8..a7d27621197431f30d6d5d93c46b3920fb042d38 100644 (file)
--- a/cinder/volume/drivers/glusterfs.py
+++ b/cinder/volume/drivers/glusterfs.py
@@ -596,6 +596,12 @@ class GlusterfsDriver(nfs.RemoteFsDriver):
                 # file as base.
                 msg = _('No base file found for %s.') % snapshot_path
                 raise exception.GlusterfsException(msg)
+
+            base_path = os.path.join(
+                self._local_volume_dir(snapshot['volume']), base_file)
+            base_file_img_info = self._qemu_img_info(base_path)
+            new_base_file = base_file_img_info.backing_file
+
             base_id = None
             info_path = self._local_path_volume(snapshot['volume']) + '.info'
             snap_info = self._read_info_file(info_path)
@@ -614,7 +620,8 @@ class GlusterfsDriver(nfs.RemoteFsDriver):
                 'active_file': active_file,
                 'snapshot_file': snapshot_file,
                 'base_file': base_file,
-                'base_id': base_id
+                'base_id': base_id,
+                'new_base_file': new_base_file
             }
 
             return self._delete_snapshot_online(context,
@@ -724,8 +731,15 @@ class GlusterfsDriver(nfs.RemoteFsDriver):
             # info['base'] => snapshot_file
 
             file_to_delete = info['base_file']
+            if info['base_id'] is None:
+                # Passing base=none to blockRebase ensures that
+                # libvirt blanks out the qcow2 backing file pointer
+                new_base = None
+            else:
+                new_base = info['new_base_file']
+                snap_info[info['base_id']] = info['snapshot_file']
 
-            delete_info = {'file_to_merge': info['base_file'],
+            delete_info = {'file_to_merge': new_base,
                            'merge_target_file': None,  # current
                            'type': 'qcow2',
                            'volume_id': snapshot['volume']['id']}