Re: [Qemu-devel] [PATCH 5/7] block: allow migration to work with image files (v2)

[Anthony Liguori <anthony@codemonkey.ws>]

On 11/14/2011 02:36 PM, Kevin Wolf wrote:
> Am 14.11.2011 21:12, schrieb Anthony Liguori:
>>> I don't think it makes even sense logically: bdrv_invalidate_cache()
>>> means "throw all your caches away and refetch everything from disk".
>>> What do we gain from doing this on stop? To some degree I could
>>> understand if you did it on cont, so that you can modify an image on the
>>> host while the VM is stopped (though I would still consider it criminal
>>> :-)).
>>
>> Michael basically was trying to avoid having a VM's state change after you
>> stopped the guest.
>>
>> With something like cache=unsafe that periodically flushes based on a timer (I
>> think), you want to make sure that that doesn't happen after stop occurs.
>
> This is a good point, but neither does cache=unsafe use a timer nor can
> I see how invalidating the cache would avoid such behaviour. And
> throwing away any unwritten changes doesn't really make it better.

I don't think there's any real harm to removing it so I'll remove it in the next 
rev.

Regards,

Anthony Liguori

>
> Kevin
>