Re: [Qemu-devel] [PATCH V6 3/6] qemu-iotests: add 058 internal snapshot export with qemu-nbd case

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

于 2013/12/3 21:45, Stefan Hajnoczi 写道:
> On Fri, Nov 22, 2013 at 12:27:09PM +0800, Wenchao Xia wrote:
>> +nbd_snapshot_port=10850
>> +nbd_snapshot_img="nbd:127.0.0.1:$nbd_snapshot_port"
>> +
>> +_export_nbd_snapshot()
>> +{
>> +    $QEMU_NBD -v -t -b 127.0.0.1 -p $nbd_snapshot_port "$TEST_IMG" -l $1 &
>
> Please use a UNIX domain socket so that multiple qemu-iotests instances
> can run on the same host in parallel.  The socket should be in the
> scratch directory just like the temporary image files.
>
>> +    NBD_SNAPSHOT_PID=$!
>> +    sleep 1
>
> qemu-nbd might not start within 1 second on a heavily loaded host.
>
> To make this test case reliable please use a loop (e.g. wait for UNIX
> domain socket to appear for up to 30 seconds).
>
> If you feel qemu-nbd doesn't offer a good interface for reliable
> startup, feel free to extend it.  Test cases must be reliable and
> ideally shouldn't waste time sleeping.
>
   I will improve this case.