Revert "Ceph driver should respect the `--incremental` option for backups"

This reverts commit 797c5aa785.

That patch doesn't really fix the Ceph full backup issue.

When doing a non incremental Ceph to Ceph backup, instead of doing a
full backup that is ussable by the incremental feature, it creates a
full backup as if it where a backup from a non Ceph volume, which then
cannot be used by the incremental feature.

Change-Id: I73a40babf5cb13956e44d4caef3d0ff7ef698048

cinder/backup/drivers/ceph.py

@@ -169,9 +169,9 @@ class CephBackupDriver(driver.BackupDriver):
     Backups may be stored in their own pool or even cluster. Store location is
     defined by the Ceph conf file and service config options supplied.
 
-    Only if the incremental option is specified and the source volume is itself
-    an RBD volume, the backup will be performed using incremental differential
-    backups which *should* give a performance gain.
+    If the source volume is itself an RBD volume, the backup will be performed
+    using incremental differential backups which *should* give a performance
+    gain.
     """
 
     def __init__(self, context, db=None, execute=None):
@@ -910,9 +910,8 @@ class CephBackupDriver(driver.BackupDriver):
     def backup(self, backup, volume_file, backup_metadata=True):
         """Backup volume and metadata (if available) to Ceph object store.
 
-        If the source volume is an RBD and we use the `incremental`
-        option we will attempt to do an incremental/differential backup,
-        otherwise a full copy is performed.
+        If the source volume is an RBD we will attempt to do an
+        incremental/differential backup, otherwise a full copy is performed.
         If this fails we will attempt to fall back to full copy.
         """
         volume = self.db.volume_get(self.context, backup.volume_id)
@@ -927,13 +926,13 @@ class CephBackupDriver(driver.BackupDriver):
         volume_file.seek(0)
         length = self._get_volume_size_gb(volume)
 
-        if backup.parent_id and self._file_is_rbd(volume_file):
+        do_full_backup = False
+        if self._file_is_rbd(volume_file):
             # If volume an RBD, attempt incremental backup.
             LOG.debug("Volume file is RBD: attempting incremental backup.")
             try:
                 updates = self._backup_rbd(backup, volume_file,
                                            volume.name, length)
-                do_full_backup = False
             except exception.BackupRBDOperationFailed:
                 LOG.debug("Forcing full backup of volume %s.", volume.id)
                 do_full_backup = True

cinder/tests/unit/backup/drivers/test_backup_ceph.py

@@ -483,15 +483,8 @@ class BackupCephTestCase(test.TestCase):
                                  {'name': 'backup.mock.snap.15341241.90'},
                                  {'name': 'backup.mock.snap.199994362.10'}])
 
-                            self.backup.parent_id = fake.UUID1
                             output = self.service.backup(self.backup, rbdio)
-
-                            # Confirm that the backup process is not able to
-                            # find the parent backup for incremental (creates
-                            # a full backup) and requests the DB to be changed
-                            # to reflect that there's no parent (is full
-                            # backup).
-                            self.assertIsNone(output['parent_id'])
+                            self.assertDictEqual({}, output)
 
                             self.assertEqual(['popen_init',
                                               'read',
@@ -509,16 +502,10 @@ class BackupCephTestCase(test.TestCase):
 
     @common_mocks
     def test_backup_volume_from_rbd_set_parent_id(self):
-        """Test volume from rbd with parent id.
-
-        If the backup has parent_id an incremental backup should
-        be performance.
-        """
         with mock.patch.object(self.service, '_backup_rbd') as \
                 mock_backup_rbd, mock.patch.object(self.service,
                                                    '_backup_metadata'):
-            self.backup.parent_id = fake.UUID1
-            mock_backup_rbd.return_value = {'parent_id': fake.UUID1}
+            mock_backup_rbd.return_value = {'parent_id': 'mock'}
             image = self.service.rbd.Image()
             meta = linuxrbd.RBDImageMetadata(image,
                                              'pool_foo',
@@ -526,7 +513,7 @@ class BackupCephTestCase(test.TestCase):
                                              'conf_foo')
             rbdio = linuxrbd.RBDVolumeIOWrapper(meta)
             output = self.service.backup(self.backup, rbdio)
-            self.assertDictEqual({'parent_id': fake.UUID1}, output)
+            self.assertDictEqual({'parent_id': 'mock'}, output)
 
     @common_mocks
     def test_backup_volume_from_rbd_set_parent_id_none(self):
@@ -609,7 +596,6 @@ class BackupCephTestCase(test.TestCase):
         """
         backup_name = self.service._get_backup_base_name(self.backup_id,
                                                          diff_format=True)
-        self.backup.parent_id = fake.UUID1
 
         def mock_write_data():
             self.volume_file.seek(0)

releasenotes/notes/ceph-driver-full-backups-by-default-c0677d4b6358cf14.yaml

@@ -1,10 +0,0 @@
----
-upgrade:
-  - Default behavior of ceph backups upgraded (no longer incremental by
-    default) to keep consistency between drivers.
-fixes:
-  - Volume backup service with Ceph driver will now respect the `--incremental`
-    option for backups (this new behavior will be only available for Ceph
-    volumes, we still don't support incremental for non Ceph volumes).
-    If the incremental flag is not specified then a new full backup will
-    always be created.