Re: [PATCH v3 7/7] iotests: copy-before-write: add cases for cbw-timeout option

[Hanna Reitz]

On 06.04.22 20:08, Vladimir Sementsov-Ogievskiy wrote:
> Add two simple test-cases: timeout failure with
> break-snapshot-on-cbw-error behavior and similar with
> break-guest-write-on-cbw-error behavior.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org>
> ---
>   tests/qemu-iotests/tests/copy-before-write    | 78 +++++++++++++++++++
>   .../qemu-iotests/tests/copy-before-write.out  |  4 +-
>   2 files changed, 80 insertions(+), 2 deletions(-)
>
> diff --git a/tests/qemu-iotests/tests/copy-before-write 
> b/tests/qemu-iotests/tests/copy-before-write
> index a32608f597..5c90b8cd50 100755
> --- a/tests/qemu-iotests/tests/copy-before-write
> +++ b/tests/qemu-iotests/tests/copy-before-write
> @@ -122,6 +122,84 @@ read 1048576/1048576 bytes at offset 0
>   1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
>   """)
>   
> +    def do_cbw_timeout(self, on_cbw_error):
> +        result = self.vm.qmp('object-add', {
> +            'qom-type': 'throttle-group',
> +            'id': 'group0',
> +            'limits': {'bps-write': 300 * 1024}

Hm, yes, I can’t find a way to make this work without your other 
series.  For some reason, not even -accel tcg helps; and using qtest to 
advance the virtual clock doesn’t really help because the qemu-io 
commands block while the request is throttled.

One thing that should work would be to run everything in a 
qemu-storage-daemon instance, and then having qemu-io access an NBD 
export...