[Qemu-devel] Re: [PATCH 6/6] Continue a migrated vm is a bad idea

[Juan Quintela <quintela@redhat.com>]

Avi Kivity <avi@redhat.com> wrote:
> On 08/19/2009 05:07 AM, Juan Quintela wrote:
>> index ea5c33a..762a9a5 100644
>> --- a/monitor.c
>> +++ b/monitor.c
>> @@ -567,6 +567,11 @@ static void do_cont(Monitor *mon)
>>   {
>>       struct bdrv_iterate_context context = { mon, 0 };
>>
>> +    if (unlikely(vm_has_migrated)) {
>> +        monitor_printf(mon, "this vm has migrated to other machine\n");
>> +        monitor_printf(mon, "You have to load other vm\n");
>> +        return;
>> +    }
>>    
>
> You don't know whether the guest is running on the other side.  It may
> be that the control program started the other side stopped, and after
> migration completes decides which side to continue running.

Only works if migration suceeded and was done in _non_ autostart node.
Have to debug this very bug.  User thought that he had done _nothing_
on the destination side, and that then stoping it, and continue in the
source side was a good idea.

He didn't understand why he had disk corruption, obviosly qemu had a
bug.  I haven't found a better approach to fix this bug.  If you have a
better idea of what to do in this case, I am all ears.

The reason that I created the patch is that if the user didn't got it
right, it gets disk corruption.

Later, Juan.