[Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes"

[Michael Tokarev]

24.08.2010 16:21, Stefan Hajnoczi wrote:
> On Tue, Aug 24, 2010 at 12:40 PM, Kevin Wolf <address@hidden> wrote:
>> Am 24.08.2010 13:02, schrieb Stefan Hajnoczi:
>>> QEMU 0.12.5 has qcow2 sync metadata writes in commit
>>> 37060c28e522843fbf6f7e59af745dfcb05b132c.  Was the performance
>>> regression spotted on 0.12.5 or 0.13?
>>
>> Both. You mean we should consider a 0.12.6 if we decide to revert? I
>> think so far 0.12.5 was planned to be last 0.12.x release.
> 
> Yes, especially if distros will revert the patches manually without an
> upstream release.  I can see arguments for either way though.

Note that for 0.12 there's no other option than to revert the
whole thing.  Because, well, there's no "cache=unsafe" there,
not to say about it being the default.  And quemu-kvm breaks
the user's systems in the middle of stable series (by "breaks"
I mean making their working guests unusable).

/mjt