From: Eric Harney <eharney@redhat.com>
Date: Thu, 19 Dec 2013 00:11:44 +0000 (-0500)
Subject: GlusterFS: Use correct base argument when deleting attached snaps
X-Git-Url: https://review.fuel-infra.org/gitweb?a=commitdiff_plain;h=186221779a92002ff9fa13c254710c0abb3803be;p=openstack-build%2Fcinder-build.git

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 23874a9b4..69a616e09 100644
--- 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 927969216..a7d276211 100644
--- 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']}