Re: [Qemu-devel] [PATCH for-4.1 2/2] iotests: Test backup job with two guest writes

[Vladimir Sementsov-Ogievskiy]

01.08.2019 18:12, Max Reitz wrote:
> Perform two guest writes to not yet backed up areas of an image, where
> the former touches an inner area of the latter.
> 
> Before HEAD^, copy offloading broke this in two ways:
> (1) The output differs from the reference output (what the source was
>      before the guest writes).
> (2) But you will not see that in the failing output, because the job
>      offset is reported as being greater than the job length.  This is
>      because one cluster is copied twice, and thus accounted for twice,
>      but of course the job length does not increase.
> 
> Signed-off-by: Max Reitz <address@hidden>
> ---
>   tests/qemu-iotests/056     | 34 ++++++++++++++++++++++++++++++++++
>   tests/qemu-iotests/056.out |  4 ++--
>   2 files changed, 36 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/qemu-iotests/056 b/tests/qemu-iotests/056
> index f40fc11a09..d7198507f5 100755
> --- a/tests/qemu-iotests/056
> +++ b/tests/qemu-iotests/056
> @@ -133,6 +133,7 @@ class BackupTest(iotests.QMPTestCase):
>           self.vm = iotests.VM()
>           self.test_img = img_create('test')
>           self.dest_img = img_create('dest')
> +        self.ref_img = img_create('ref')
>           self.vm.add_drive(self.test_img)
>           self.vm.launch()
>   
> @@ -140,6 +141,7 @@ class BackupTest(iotests.QMPTestCase):
>           self.vm.shutdown()
>           try_remove(self.test_img)
>           try_remove(self.dest_img)
> +        try_remove(self.ref_img)
>   
>       def hmp_io_writes(self, drive, patterns):
>           for pattern in patterns:
> @@ -177,6 +179,38 @@ class BackupTest(iotests.QMPTestCase):
>               self.assert_qmp(event, 'data/error', qerror)
>               return False
>   
> +    def test_overlapping_writes(self):
> +        # Write something to back up
> +        self.hmp_io_writes('drive0', [('42', '0M', '2M')])
> +
> +        # Create a reference backup
> +        self.qmp_backup_and_wait(device='drive0', format=iotests.imgfmt,
> +                                 sync='full', target=self.ref_img)
> +
> +        # Now to the test backup: We simulate the following guest
> +        # writes:
> +        # (1) [1M + 64k, 1M + 128k): Afterwards, everything in that
> +        #     area should be in the target image, and we must not copy
> +        #     it again (because the source image has changed now)
> +        #     (64k is the job's cluster size)
> +        # (2) [1M, 2M): The backup job must not get overeager.  It
> +        #     must copy [1M, 1M + 64k) and [1M + 128k, 2M) separately,
> +        #     but not the area in between.
> +
> +        self.qmp_backup(device='drive0', format=iotests.imgfmt, sync='full',
> +                        target=self.dest_img, speed=1)
> +
> +        self.hmp_io_writes('drive0', [('23', '%ik' % (1024 + 64), '64k'),
> +                                      ('66', '1M', '1M')])
> +
> +        # Let the job complete
> +        res = self.vm.qmp('block-job-set-speed', device='drive0', speed=0)
> +        self.assert_qmp(res, 'return', {})
> +        self.qmp_backup_wait('drive0')
> +
> +        self.assertTrue(iotests.compare_images(self.ref_img, self.dest_img),
> +                        'target image does not match reference image')
> +
>       def test_dismiss_false(self):
>           res = self.vm.qmp('query-block-jobs')
>           self.assert_qmp(res, 'return', [])
> diff --git a/tests/qemu-iotests/056.out b/tests/qemu-iotests/056.out
> index dae404e278..36376bed87 100644
> --- a/tests/qemu-iotests/056.out
> +++ b/tests/qemu-iotests/056.out
> @@ -1,5 +1,5 @@
> -.........
> +..........
>   ----------------------------------------------------------------------
> -Ran 9 tests
> +Ran 10 tests
>   
>   OK
> 

Failed for me:
-..........
+qemu-img: Could not open 
'/work/src/qemu/master/tests/qemu-iotests/scratch/dest.qcow2': Failed to get 
shared "write" lock
+Is another process using the image 
[/work/src/qemu/master/tests/qemu-iotests/scratch/dest.qcow2]?
+......F...
+======================================================================
+FAIL: test_overlapping_writes (__main__.BackupTest)
+----------------------------------------------------------------------
+Traceback (most recent call last):
+  File "056", line 212, in test_overlapping_writes
+    'target image does not match reference image')
+AssertionError: False is not true : target image does not match reference image
+
  ----------------------------------------------------------------------
  Ran 10 tests

-OK
+FAILED (failures=1)



So, with applied

@@ -207,6 +207,7 @@ class BackupTest(iotests.QMPTestCase):
          res = self.vm.qmp('block-job-set-speed', device='drive0', speed=0)
          self.assert_qmp(res, 'return', {})
          self.qmp_backup_wait('drive0')
+        self.vm.shutdown()

          self.assertTrue(iotests.compare_images(self.ref_img, self.dest_img),
                          'target image does not match reference image')



Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>
Tested-by: Vladimir Sementsov-Ogievskiy <address@hidden>

-- 
Best regards,
Vladimir