RBD: Cleanup temporary file during exception

During copy image to encrypted volume operation, we create a
temporary image file to convert source image into an encrypted
image and rename it to source image name.
If any error occurs during this process, there is no code to
cleanup the temporary '.luks' file.
This patch adds the following cleanup.

Change-Id: I05dfc996a635299990fdafba841ab6c4fd7d32c7
Closes-Bug: 1873738

cinder/image/image_utils.py

@@ -243,6 +243,10 @@ def _convert_image(prefix, source, dest, out_format,
                    passphrase_file=None, compress=False):
     """Convert image to other format.
 
+    NOTE: If the qemu-img convert command fails and this function raises an
+    exception, a non-empty dest file may be left in the filesystem.
+    It is the responsibility of the caller to decide what to do with this file.
+
     :param prefix: command prefix, i.e. cgexec for throttling
     :param source: source filename
     :param dest: destination filename

cinder/tests/unit/volume/drivers/test_rbd.py

@@ -1309,6 +1309,39 @@ class RBDTestCase(test.TestCase):
                                     mock_image_service, None]
                             self.driver.copy_image_to_volume(*args)
 
+    @mock.patch('cinder.volume.drivers.rbd.fileutils.delete_if_exists')
+    @mock.patch('cinder.volume.volume_utils.check_encryption_provider',
+                return_value={'encryption_key_id': fake.ENCRYPTION_KEY_ID})
+    @mock.patch('cinder.image.image_utils.convert_image')
+    def _copy_image_encrypted(self, mock_convert, mock_encrypt_key,
+                              mock_temp_delete):
+        key_mgr = fake_keymgr.fake_api()
+        self.mock_object(castellan.key_manager, 'API', return_value=key_mgr)
+        key_id = key_mgr.store(self.context, KeyObject())
+        self.volume_a.encryption_key_id = key_id
+
+        enc_info = {'encryption_key_id': key_id,
+                    'cipher': 'aes-xts-essiv',
+                    'key_size': 256}
+        with mock.patch('cinder.volume.volume_utils.check_encryption_provider',
+                        return_value=enc_info), \
+                mock.patch('cinder.volume.drivers.rbd.open'), \
+                mock.patch('os.rename'):
+            with mock.patch.object(tempfile, 'NamedTemporaryFile'):
+                with mock.patch.object(os.path, 'exists') as mock_exists:
+                    mock_exists.return_value = True
+                    with mock.patch.object(image_utils, 'fetch_to_raw'):
+                        with mock.patch.object(self.driver, 'delete_volume'):
+                            with mock.patch.object(self.driver, '_resize'):
+                                mock_image_service = mock.MagicMock()
+                                args = [self.context, self.volume_a,
+                                        mock_image_service, None]
+                                self.driver.copy_image_to_encrypted_volume(
+                                    *args)
+                                mock_temp_delete.assert_called()
+                                self.assertEqual(1,
+                                                 mock_temp_delete.call_count)
+
     @common_mocks
     def test_copy_image_no_volume_tmp(self):
         self.cfg.image_conversion_dir = None
@@ -1319,6 +1352,11 @@ class RBDTestCase(test.TestCase):
         self.cfg.image_conversion_dir = '/var/run/cinder/tmp'
         self._copy_image()
 
+    @common_mocks
+    def test_copy_image_volume_tmp_encrypted(self):
+        self.cfg.image_conversion_dir = '/var/run/cinder/tmp'
+        self._copy_image_encrypted()
+
     @ddt.data(True, False)
     @common_mocks
     @mock.patch('cinder.volume.drivers.rbd.RBDDriver._get_usage_info')

cinder/volume/drivers/rbd.py

@@ -1580,6 +1580,7 @@ class RBDDriver(driver.CloneableImageVD, driver.MigrateVD,
 
             # Convert the raw image to luks
             dest_image_path = src_image_path + '.luks'
+            try:
                 image_utils.convert_image(src_image_path, dest_image_path,
                                           'luks', src_format='raw',
                                           cipher_spec=cipher_spec,
@@ -1587,6 +1588,8 @@ class RBDDriver(driver.CloneableImageVD, driver.MigrateVD,
 
                 # Replace the original image with the now encrypted image
                 os.rename(dest_image_path, src_image_path)
+            finally:
+                fileutils.delete_if_exists(dest_image_path)
 
     def _copy_image_to_volume(self, context, volume, image_service, image_id,
                               encrypted=False):

releasenotes/notes/cleanup-rbd-temp-file-during-convert-fail-3848e9dbe7e15fc6.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    `Bug #1873738 <https://bugs.launchpad.net/cinder/+bug/1873738>`_: RBD Driver:
+    Added cleanup for residue destination file if the copy image to encrypted volume
+    operation fails.