Re: [Qemu-devel] Re: KVM call agenda for July 27

[Anthony Liguori <anthony@codemonkey.ws>]

On 07/27/2010 10:22 AM, Markus Armbruster wrote:
> Kevin Wolf<kwolf@redhat.com>  writes:
>
>    
>> Am 27.07.2010 15:00, schrieb Anthony Liguori:
>>      
>>> On 07/27/2010 02:19 AM, Markus Armbruster wrote:
>>>        
>>>> Anthony Liguori<anthony@codemonkey.ws>   writes:
>>>>
>>>>
>>>>          
>>>>> - any additional input on probed_raw?
>>>>>
>>>>>            
>>>> Isn't it a fait accompli?  I stopped providing input when commit
>>>> 79368c81 appeared.
>>>>
>>>>          
>>> No.  79368c81 was to close the security hole (and I do consider it a
>>> security hole).  But as I mentioned on the list, I'm also not satisfied
>>> with it and that's why I proposed probed_raw.  I was hoping to get a
>>> little more input from those that objected to 79368c81 as to whether
>>> probed_raw was more agreeable.
>>>        
>> Actually I believe qraw is less agreeable. It just too much magic. You
>> wouldn't expect that your raw images are turned into some other format
>> that you can't mount or use with any other program any more.
>>      
> I also dislike probed_raw, for the same reasons.
>
> Raw can't be probed safely, by its very nature.  For historical reasons,
> we try anyway.  I think we should stop doing that, even though that
> breaks existing use relying on the misfeature.  Announce it now, spit
> out scary warnings, kill it for good 1-2 releases later.
>
> If we're unwilling to do that, then I'd *strongly* prefer doing nothing
> over silently messing with the raw writes to sector 0 (so does
> Christoph, and he explained why).

If we add docs/deprecated-features.txt, schedule removal for at least 1 
year in the future, and put a warning in the code that prints whenever 
raw is probed, I think I could warm up to this.

Since libvirt should be insulating users from this today, I think the 
fall out might not be terrible.

Regards,

Anthony Liguori

>    But since it's already committed, I
> figure it's here to stay.
>