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From: Juan Quintela <quintela@redhat.com>
In-Reply-To: <4A8D0C00.6080402@redhat.com> (Avi Kivity's message of "Thu, 20
	Aug 2009 11:40:32 +0300")
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Date: Thu, 20 Aug 2009 11:10:28 +0200
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Subject: [Qemu-devel] Re: [PATCH 6/6] Continue a migrated vm is a bad idea
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To: Avi Kivity <avi@redhat.com>
Cc: qemu-devel@nongnu.org

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.