[Qemu-devel] ping Re: [PATCH 4/6] dirty-bitmaps: clean-up bitmaps loading and migration logic

[Vladimir Sementsov-Ogievskiy]

ping

18.09.2018 13:37, Vladimir Sementsov-Ogievskiy wrote:
> 17.09.2018 21:33, John Snow wrote:
>>
>> On 09/17/2018 11:51 AM, Vladimir Sementsov-Ogievskiy wrote:
>>> Hmm, ping, anybody here ?)
>>>
>> Was preparing to stage on Friday, working on it now.
>>
>> I never understood why you forbid the transfer of read only bitmaps
>> though, can you point that out for me?
>>
>> --js
>
> readonly bitmap - means it is not marked in_use in qcow2 file.
>
> Hm, I don't remember exact reason, but at least for shared migration 
> it is unsafe to migrate readonly bitmap without special handling: we 
> migrate it, it becomes not-readonly, it changes in RAM, then (assume) 
> storing failed and we have old version ofthe bitmap in qcow2, which is 
> not marked in_use.. So it should be somehow carefully handled, the 
> simplest option is just to forbid it.
>


-- 
Best regards,
Vladimir