Re: [Qemu-block] [PATCH v6 20/21] iotests: add incremental backup failure recovery test

[Kevin Wolf]

Am 18.04.2015 um 01:50 hat John Snow geschrieben:
> Test the failure case for incremental backups.
> 
> Signed-off-by: John Snow <address@hidden>
> Reviewed-by: Max Reitz <address@hidden>
> ---
>  tests/qemu-iotests/124     | 57 
> ++++++++++++++++++++++++++++++++++++++++++++++
>  tests/qemu-iotests/124.out |  4 ++--
>  2 files changed, 59 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/qemu-iotests/124 b/tests/qemu-iotests/124
> index 5c3b434..95f6de5 100644
> --- a/tests/qemu-iotests/124
> +++ b/tests/qemu-iotests/124
> @@ -240,6 +240,63 @@ class TestIncrementalBackup(iotests.QMPTestCase):
>          self.check_backups()
>  
>  
> +    def test_incremental_failure(self):
> +        '''Test: Verify backups made after a failure are correct.
> +
> +        Simulate a failure during an incremental backup block job,
> +        emulate additional writes, then create another incremental backup
> +        afterwards and verify that the backup created is correct.
> +        '''
> +
> +        # Create a blkdebug interface to this img as 'drive1',
> +        # but don't actually create a new image.
> +        drive1 = self.add_node('drive1', self.drives[0]['fmt'],
> +                               path=self.drives[0]['file'],
> +                               backup=self.drives[0]['backup'])
> +        result = self.vm.qmp('blockdev-add', options={
> +            'id': drive1['id'],
> +            'driver': drive1['fmt'],
> +            'file': {
> +                'driver': 'blkdebug',
> +                'image': {
> +                    'driver': 'file',
> +                    'filename': drive1['file']
> +                },
> +                'set-state': [{
> +                    'event': 'flush_to_disk',
> +                    'state': 1,
> +                    'new_state': 2
> +                }],
> +                'inject-error': [{
> +                    'event': 'read_aio',
> +                    'errno': 5,
> +                    'state': 2,
> +                    'immediately': False,
> +                    'once': True
> +                }],
> +            }
> +        })
> +        self.assert_qmp(result, 'return', {})

John, how naughty of you!

It's interesting how many tests break now that I tried to add some
advisory qcow2 locking so that people don't constantly break their
images with 'qemu-img snapshot' while the VM is running.

I think this one is a bug in the test case. I'm not completely sure how
to fix it, though. Can we move the blkdebug layer to the top level? I
think reusing the same qcow2 BDS (using a node name reference) would be
okay. We just need to avoid opening the qcow2 layer twice for the same
image.

Kevin