From 59c6ad96ce35c9deecfedb5698c5806f3883a8af Mon Sep 17 00:00:00 2001 From: Dmitry Tantsur Date: Fri, 31 Mar 2023 15:39:50 +0200 Subject: Always fall back from hard linking to copying files The current check is insufficient: it passes for Kubernetes shared volumes, although hard-linking between them is not possible. This patch changes the approach to trying a hard link and falling back to copyfile instead. The patch relies on optimizations in Python 3.8 and thus should not be backported beyond the Zed series to avoid performance regression. Change-Id: I929944685b3ac61b2f63d2549198a2d8a1c8fe35 --- ironic/common/image_service.py | 35 +++---- ironic/tests/unit/common/test_image_service.py | 107 ++++----------------- .../notes/cross-link-1ffd1a4958f14fd7.yaml | 5 + 3 files changed, 40 insertions(+), 107 deletions(-) create mode 100644 releasenotes/notes/cross-link-1ffd1a4958f14fd7.yaml diff --git a/ironic/common/image_service.py b/ironic/common/image_service.py index 5280ee6bc..4b95b5152 100644 --- a/ironic/common/image_service.py +++ b/ironic/common/image_service.py @@ -34,10 +34,6 @@ from ironic.common import utils from ironic.conf import CONF IMAGE_CHUNK_SIZE = 1024 * 1024 # 1mb -# NOTE(kaifeng) Image will be truncated to 2GiB by sendfile, -# we use a large chunk size here for a better performance -# while keep the chunk size less than the size limit. -SENDFILE_CHUNK_SIZE = 1024 * 1024 * 1024 # 1Gb LOG = log.getLogger(__name__) @@ -264,26 +260,23 @@ class FileImageService(BaseImageService): """ source_image_path = self.validate_href(image_href) dest_image_path = image_file.name - local_device = os.stat(dest_image_path).st_dev try: - # We should have read and write access to source file to create - # hard link to it. - if (local_device == os.stat(source_image_path).st_dev - and os.access(source_image_path, os.R_OK | os.W_OK)): - image_file.close() - os.remove(dest_image_path) + image_file.close() + os.remove(dest_image_path) + + try: os.link(source_image_path, dest_image_path) + except OSError as exc: + LOG.debug('Could not create a link from %(src)s to %(dest)s, ' + 'will copy the content instead. Error: %(exc)s.', + {'src': source_image_path, 'dest': dest_image_path, + 'exc': exc}) else: - filesize = os.path.getsize(source_image_path) - offset = 0 - with open(source_image_path, 'rb') as input_img: - while offset < filesize: - count = min(SENDFILE_CHUNK_SIZE, filesize - offset) - nbytes_out = os.sendfile(image_file.fileno(), - input_img.fileno(), - offset, - count) - offset += nbytes_out + return + + # NOTE(dtantsur): starting with Python 3.8, copyfile() uses + # efficient copying (i.e. sendfile) under the hood. + shutil.copyfile(source_image_path, dest_image_path) except Exception as e: raise exception.ImageDownloadFailed(image_href=image_href, reason=str(e)) diff --git a/ironic/tests/unit/common/test_image_service.py b/ironic/tests/unit/common/test_image_service.py index 197518e1a..297a1b4b9 100644 --- a/ironic/tests/unit/common/test_image_service.py +++ b/ironic/tests/unit/common/test_image_service.py @@ -10,7 +10,6 @@ # License for the specific language governing permissions and limitations # under the License. -import builtins import datetime from http import client as http_client import io @@ -483,119 +482,55 @@ class FileImageServiceTestCase(base.TestCase): 'properties': {}, 'no_cache': True}, result) + @mock.patch.object(shutil, 'copyfile', autospec=True) @mock.patch.object(os, 'link', autospec=True) @mock.patch.object(os, 'remove', autospec=True) - @mock.patch.object(os, 'access', return_value=True, autospec=True) - @mock.patch.object(os, 'stat', autospec=True) @mock.patch.object(image_service.FileImageService, 'validate_href', autospec=True) - def test_download_hard_link(self, _validate_mock, stat_mock, access_mock, - remove_mock, link_mock): + def test_download_hard_link(self, _validate_mock, remove_mock, link_mock, + copy_mock): _validate_mock.return_value = self.href_path - stat_mock.return_value.st_dev = 'dev1' file_mock = mock.Mock(spec=io.BytesIO) file_mock.name = 'file' self.service.download(self.href, file_mock) _validate_mock.assert_called_once_with(mock.ANY, self.href) - self.assertEqual(2, stat_mock.call_count) - access_mock.assert_called_once_with(self.href_path, os.R_OK | os.W_OK) remove_mock.assert_called_once_with('file') link_mock.assert_called_once_with(self.href_path, 'file') + copy_mock.assert_not_called() - @mock.patch.object(os, 'sendfile', return_value=42, autospec=True) - @mock.patch.object(os.path, 'getsize', return_value=42, autospec=True) - @mock.patch.object(builtins, 'open', autospec=True) - @mock.patch.object(os, 'access', return_value=False, autospec=True) - @mock.patch.object(os, 'stat', autospec=True) - @mock.patch.object(image_service.FileImageService, 'validate_href', - autospec=True) - def test_download_copy(self, _validate_mock, stat_mock, access_mock, - open_mock, size_mock, copy_mock): - _validate_mock.return_value = self.href_path - stat_mock.return_value.st_dev = 'dev1' - file_mock = mock.MagicMock(spec=io.BytesIO) - file_mock.name = 'file' - input_mock = mock.MagicMock(spec=io.BytesIO) - open_mock.return_value = input_mock - self.service.download(self.href, file_mock) - _validate_mock.assert_called_once_with(mock.ANY, self.href) - self.assertEqual(2, stat_mock.call_count) - access_mock.assert_called_once_with(self.href_path, os.R_OK | os.W_OK) - copy_mock.assert_called_once_with(file_mock.fileno(), - input_mock.__enter__().fileno(), - 0, 42) - - @mock.patch.object(os, 'sendfile', autospec=True) - @mock.patch.object(os.path, 'getsize', return_value=42, autospec=True) - @mock.patch.object(builtins, 'open', autospec=True) - @mock.patch.object(os, 'access', return_value=False, autospec=True) - @mock.patch.object(os, 'stat', autospec=True) + @mock.patch.object(shutil, 'copyfile', autospec=True) + @mock.patch.object(os, 'link', autospec=True) + @mock.patch.object(os, 'remove', autospec=True) @mock.patch.object(image_service.FileImageService, 'validate_href', autospec=True) - def test_download_copy_segmented(self, _validate_mock, stat_mock, - access_mock, open_mock, size_mock, - copy_mock): - # Fake a 3G + 1k image - chunk_size = image_service.SENDFILE_CHUNK_SIZE - fake_image_size = chunk_size * 3 + 1024 - fake_chunk_seq = [chunk_size, chunk_size, chunk_size, 1024] + def test_download_copy(self, _validate_mock, remove_mock, link_mock, + copy_mock): _validate_mock.return_value = self.href_path - stat_mock.return_value.st_dev = 'dev1' + link_mock.side_effect = PermissionError file_mock = mock.MagicMock(spec=io.BytesIO) file_mock.name = 'file' - input_mock = mock.MagicMock(spec=io.BytesIO) - open_mock.return_value = input_mock - size_mock.return_value = fake_image_size - copy_mock.side_effect = fake_chunk_seq self.service.download(self.href, file_mock) _validate_mock.assert_called_once_with(mock.ANY, self.href) - self.assertEqual(2, stat_mock.call_count) - access_mock.assert_called_once_with(self.href_path, os.R_OK | os.W_OK) - copy_calls = [mock.call(file_mock.fileno(), - input_mock.__enter__().fileno(), - chunk_size * i, - fake_chunk_seq[i]) for i in range(4)] - copy_mock.assert_has_calls(copy_calls) - size_mock.assert_called_once_with(self.href_path) - - @mock.patch.object(os, 'remove', side_effect=OSError, autospec=True) - @mock.patch.object(os, 'access', return_value=True, autospec=True) - @mock.patch.object(os, 'stat', autospec=True) - @mock.patch.object(image_service.FileImageService, 'validate_href', - autospec=True) - def test_download_hard_link_fail(self, _validate_mock, stat_mock, - access_mock, remove_mock): - _validate_mock.return_value = self.href_path - stat_mock.return_value.st_dev = 'dev1' - file_mock = mock.MagicMock(spec=io.BytesIO) - file_mock.name = 'file' - self.assertRaises(exception.ImageDownloadFailed, - self.service.download, self.href, file_mock) - _validate_mock.assert_called_once_with(mock.ANY, self.href) - self.assertEqual(2, stat_mock.call_count) - access_mock.assert_called_once_with(self.href_path, os.R_OK | os.W_OK) + link_mock.assert_called_once_with(self.href_path, 'file') + copy_mock.assert_called_once_with(self.href_path, 'file') - @mock.patch.object(os, 'sendfile', side_effect=OSError, autospec=True) - @mock.patch.object(os.path, 'getsize', return_value=42, autospec=True) - @mock.patch.object(builtins, 'open', autospec=True) - @mock.patch.object(os, 'access', return_value=False, autospec=True) - @mock.patch.object(os, 'stat', autospec=True) + @mock.patch.object(shutil, 'copyfile', autospec=True) + @mock.patch.object(os, 'link', autospec=True) + @mock.patch.object(os, 'remove', autospec=True) @mock.patch.object(image_service.FileImageService, 'validate_href', autospec=True) - def test_download_copy_fail(self, _validate_mock, stat_mock, access_mock, - open_mock, size_mock, copy_mock): + def test_download_copy_fail(self, _validate_mock, remove_mock, link_mock, + copy_mock): _validate_mock.return_value = self.href_path - stat_mock.return_value.st_dev = 'dev1' + link_mock.side_effect = PermissionError + copy_mock.side_effect = PermissionError file_mock = mock.MagicMock(spec=io.BytesIO) file_mock.name = 'file' - input_mock = mock.MagicMock(spec=io.BytesIO) - open_mock.return_value = input_mock self.assertRaises(exception.ImageDownloadFailed, self.service.download, self.href, file_mock) _validate_mock.assert_called_once_with(mock.ANY, self.href) - self.assertEqual(2, stat_mock.call_count) - access_mock.assert_called_once_with(self.href_path, os.R_OK | os.W_OK) - size_mock.assert_called_once_with(self.href_path) + link_mock.assert_called_once_with(self.href_path, 'file') + copy_mock.assert_called_once_with(self.href_path, 'file') class ServiceGetterTestCase(base.TestCase): diff --git a/releasenotes/notes/cross-link-1ffd1a4958f14fd7.yaml b/releasenotes/notes/cross-link-1ffd1a4958f14fd7.yaml new file mode 100644 index 000000000..caac13dd4 --- /dev/null +++ b/releasenotes/notes/cross-link-1ffd1a4958f14fd7.yaml @@ -0,0 +1,5 @@ +--- +fixes: + - | + Fixes ``Invalid cross-device link`` in some cases when using ``file://`` + image URLs. -- cgit v1.2.1