[PATCH v3 2/9] iotests/040: cover large and fragmented commit runs

["Denis V. Lunev" <den@openvz.org>]

From: Denis V. Lunev <den@openvz.org>

040 never commits runs long enough to span more than one block-status
query, so the answer that commit_iteration() is about to start caching
goes untested.

Add two cases on a base <- mid <- active chain, committing mid so the
job takes the regular commit path rather than active commit, and compare
base against a snapshot of mid taken before the commit. One case mixes
multi-megabyte data, zero and hole runs, the other fragments them down
to single clusters with every transition off the 512K boundary.

Reviewed-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
CC: John Snow <jsnow@redhat.com>
CC: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
---
 tests/qemu-iotests/040     | 102 ++++++++++++++++++++++++++++++++++++-
 tests/qemu-iotests/040.out |   4 +-
 2 files changed, 103 insertions(+), 3 deletions(-)

diff --git a/tests/qemu-iotests/040 b/tests/qemu-iotests/040
index 5c18e413ec..e01c9385ba 100755
--- a/tests/qemu-iotests/040
+++ b/tests/qemu-iotests/040
@@ -25,13 +25,14 @@
 import time
 import os
 import iotests
-from iotests import qemu_img, qemu_io
+from iotests import qemu_img, qemu_img_create, qemu_io, compare_images
 import struct
 import errno
 
 backing_img = os.path.join(iotests.test_dir, 'backing.img')
 mid_img = os.path.join(iotests.test_dir, 'mid.img')
 test_img = os.path.join(iotests.test_dir, 'test.img')
+reference_img = os.path.join(iotests.test_dir, 'reference.img')
 
 class ImageCommitTestCase(iotests.QMPTestCase):
     '''Abstract base class for image commit test cases'''
@@ -951,6 +952,105 @@ class TestCommitWithOverriddenBacking(iotests.QMPTestCase):
         self.vm.qmp('block-job-complete', device='commit')
         self.vm.event_wait('BLOCK_JOB_COMPLETED')
 
+class TestCommitLargeRuns(iotests.QMPTestCase):
+    """Commit runs long enough to cross commit_iteration()'s cached span."""
+
+    MB = 1024 * 1024
+    CLUSTER = 64 * 1024
+
+    # Runs several COMMIT_BUFFER_SIZE (512K) chunks long, of every kind.
+    SIZE = 32 * MB
+    LAYOUT = [
+        (0, 4 * MB, 'data'),
+        (4 * MB, 6 * MB, 'hole'),
+        (10 * MB, 4 * MB, 'data'),
+        (14 * MB, 6 * MB, 'zero'),
+        (20 * MB, 4 * MB, 'data'),
+        (24 * MB, 8 * MB, 'hole'),
+    ]
+
+    # The same, with every transition off the 512K boundary.
+    SIZE_FRAGMENTED = 384 * CLUSTER  # 24M
+    LAYOUT_FRAGMENTED = [
+        (0, 45 * CLUSTER, 'data'),
+        (45 * CLUSTER, 55 * CLUSTER, 'hole'),
+        (100 * CLUSTER, CLUSTER, 'data'),
+        (101 * CLUSTER, 49 * CLUSTER, 'zero'),
+        (150 * CLUSTER, 80 * CLUSTER, 'data'),
+        (230 * CLUSTER, CLUSTER, 'hole'),
+        (231 * CLUSTER, 69 * CLUSTER, 'data'),
+        (300 * CLUSTER, 83 * CLUSTER, 'zero'),
+        (383 * CLUSTER, CLUSTER, 'hole'),
+    ]
+
+    def setUp(self):
+        self.vm = iotests.VM()
+        self.vm.launch()
+
+    def tearDown(self):
+        self.vm.shutdown()
+        for img in (backing_img, mid_img, test_img, reference_img):
+            if os.path.exists(img):
+                os.remove(img)
+
+    def build_images(self, layout, size):
+        # A pattern of its own in base, so a misplaced cluster shows up.
+        qemu_img_create('-f', iotests.imgfmt, backing_img, str(size))
+        qemu_io('-c', f'write -P 0x11 0 {size}', backing_img)
+
+        qemu_img_create('-f', iotests.imgfmt, '-b', backing_img, '-F',
+                        iotests.imgfmt, mid_img, str(size))
+        for offset, length, kind in layout:
+            if kind == 'data':
+                qemu_io('-c', f'write -P 0x22 {offset} {length}', mid_img)
+            elif kind == 'zero':
+                qemu_io('-c', f'write -z {offset} {length}', mid_img)
+
+        # What base must equal once mid is committed into it.
+        qemu_img('convert', '-f', iotests.imgfmt, '-O', iotests.imgfmt,
+                 mid_img, reference_img)
+
+        # An empty layer above mid, so top_node=mid is not the active one.
+        qemu_img_create('-f', iotests.imgfmt, '-b', mid_img, '-F',
+                        iotests.imgfmt, test_img, str(size))
+
+        self.vm.cmd('blockdev-add', {
+            'node-name': 'base',
+            'driver': iotests.imgfmt,
+            'file': {'driver': 'file', 'filename': backing_img},
+        })
+        self.vm.cmd('blockdev-add', {
+            'node-name': 'mid',
+            'driver': iotests.imgfmt,
+            'file': {'driver': 'file', 'filename': mid_img},
+            'backing': 'base',
+        })
+        self.vm.cmd('blockdev-add', {
+            'node-name': 'active',
+            'driver': iotests.imgfmt,
+            'file': {'driver': 'file', 'filename': test_img},
+            'backing': 'mid',
+        })
+
+    def commit_and_verify(self):
+        self.vm.cmd('block-commit', job_id='commit0', device='active',
+                    top_node='mid', base_node='base')
+        self.wait_until_completed(drive='commit0')
+
+        self.vm.cmd('blockdev-del', node_name='active')
+        self.vm.cmd('blockdev-del', node_name='mid')
+        self.vm.cmd('blockdev-del', node_name='base')
+        self.assertTrue(compare_images(reference_img, backing_img))
+
+    def test_commit_large_runs(self):
+        self.build_images(self.LAYOUT, self.SIZE)
+        self.commit_and_verify()
+
+    def test_commit_fragmented_runs(self):
+        self.build_images(self.LAYOUT_FRAGMENTED, self.SIZE_FRAGMENTED)
+        self.commit_and_verify()
+
+
 if __name__ == '__main__':
     iotests.main(supported_fmts=['qcow2', 'qed'],
                  supported_protocols=['file'])
diff --git a/tests/qemu-iotests/040.out b/tests/qemu-iotests/040.out
index 1bb1dc5f0e..d2e2a2d98f 100644
--- a/tests/qemu-iotests/040.out
+++ b/tests/qemu-iotests/040.out
@@ -1,5 +1,5 @@
-.................................................................
+...................................................................
 ----------------------------------------------------------------------
-Ran 65 tests
+Ran 67 tests
 
 OK
-- 
2.53.0