Re: [Qemu-devel] [PATCH v4 03/10] iotests: add test-case to 165 to test reopening qcow2 bitmaps to RW

[John Snow]

On 8/7/19 10:12 AM, Vladimir Sementsov-Ogievskiy wrote:
> Reopening bitmaps to RW was broken prior to previous commit. Check that
> it works now.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> ---
>  tests/qemu-iotests/165     | 46 ++++++++++++++++++++++++++++++++++++--
>  tests/qemu-iotests/165.out |  4 ++--
>  2 files changed, 46 insertions(+), 4 deletions(-)
> 
> diff --git a/tests/qemu-iotests/165 b/tests/qemu-iotests/165
> index 88f62d3c6d..dd93b5a2d0 100755
> --- a/tests/qemu-iotests/165
> +++ b/tests/qemu-iotests/165
> @@ -43,10 +43,10 @@ class TestPersistentDirtyBitmap(iotests.QMPTestCase):
>          os.remove(disk)
>  
>      def mkVm(self):
> -        return iotests.VM().add_drive(disk)
> +        return iotests.VM().add_drive(disk, opts='node-name=node0')
>  
>      def mkVmRo(self):
> -        return iotests.VM().add_drive(disk, opts='readonly=on')
> +        return iotests.VM().add_drive(disk, 
> opts='readonly=on,node-name=node0')
>  
>      def getSha256(self):
>          result = self.vm.qmp('x-debug-block-dirty-bitmap-sha256',
> @@ -102,5 +102,47 @@ class TestPersistentDirtyBitmap(iotests.QMPTestCase):
>  
>          self.vm.shutdown()
>  
> +    def test_reopen_rw(self):
> +        self.vm = self.mkVm()
> +        self.vm.launch()
> +        self.qmpAddBitmap()
> +
> +        # Calculate sha256 corresponding to regions1
> +        self.writeRegions(regions1)
> +        sha256 = self.getSha256()
> +        result = self.vm.qmp('block-dirty-bitmap-clear', node='drive0',
> +                             name='bitmap0')
> +        self.assert_qmp(result, 'return', {})
> +
> +        self.vm.shutdown()
> +
> +        self.vm = self.mkVmRo()
> +        self.vm.launch()
> +
> +        # We've loaded empty bitmap
> +        assert sha256 != self.getSha256()
> +
> +        # Check that we are in RO mode
> +        self.writeRegions(regions1)
> +        assert sha256 != self.getSha256()
> +

the HMP monitor lets you attempt writes to a Read Only drive...? Or does
it error out and we just don't check the reply?

I would prefer we use an actual dirty sector count here instead; we have
the new API that should make it easy to do.

If the debug SHA changes this might be a little fragile.

ACK otherwise.

> +        result = self.vm.qmp('x-blockdev-reopen', **{
> +            'node-name': 'node0',
> +            'driver': iotests.imgfmt,
> +            'file': {
> +                'driver': 'file',
> +                'filename': disk
> +            },
> +            'read-only': False
> +        })
> +        self.assert_qmp(result, 'return', {})
> +
> +        # Check that bitmap is reopened to RW and we can write to it.
> +        self.writeRegions(regions1)
> +        assert sha256 == self.getSha256()
> +
> +        self.vm.shutdown()
> +
> +
>  if __name__ == '__main__':
>      iotests.main(supported_fmts=['qcow2'])
> diff --git a/tests/qemu-iotests/165.out b/tests/qemu-iotests/165.out
> index ae1213e6f8..fbc63e62f8 100644
> --- a/tests/qemu-iotests/165.out
> +++ b/tests/qemu-iotests/165.out
> @@ -1,5 +1,5 @@
> -.
> +..
>  ----------------------------------------------------------------------
> -Ran 1 tests
> +Ran 2 tests
>  
>  OK
> 

This is a suggestion for an even more rigorous test:

- Create bitmap
- Write a region or two
- Record the dirty count and the SHA; assert it is equal to known /
predetermined values.
- reopen RO
- verify the bitmap still exists and that the hash and count are the same.
- Stop the VM
- Start the VM in readonly mode
- verify the bitmap still exists and that the hash and count are the same.
- Reopen-RW
- verify the bitmap still exists and that the hash and count are the same.
- Write further region(s)
- Get the new dirty count and SHA, and assert it is equal to known /
predetermined values.