Re: [Qemu-devel] [PATCH 6/8] qcow2: add autoclear bit for dirty bitmaps

[Vladimir Sementsov-Ogievskiy]

On 27.08.2015 10:45, Vladimir Sementsov-Ogievskiy wrote:
> On 09.06.2015 18:50, Stefan Hajnoczi wrote:
> > On Mon, Jun 08, 2015 at 06:21:24PM +0300, Vladimir 
> > Sementsov-Ogievskiy wrote:
> > > diff --git a/block/qcow2.c b/block/qcow2.c
> > > index 406e55d..f85a55a 100644
> > > --- a/block/qcow2.c
> > > +++ b/block/qcow2.c
> > > @@ -182,6 +182,14 @@ static int 
> > > qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
> > >                   return ret;
> > >               }
> > >   +            if (!(s->autoclear_features & 
> > > QCOW2_AUTOCLEAR_DIRTY_BITMAPS) &&
> > > +                s->nb_dirty_bitmaps > 0) {
> > > +                ret = qcow2_delete_all_dirty_bitmaps(bs, errp);
> > > +                if (ret < 0) {
> > > +                    return ret;
> > > +                }
> > > +            }
> > > +
> > What if the file is read-only?
> >
> > We shouldn't modify the file in qcow2_read_extensions().
> But where? In qcow2_open? Or nowhere? I think auto clear extensions 
> should be cleared automatically..

May be, move clearing to qemu-img, and just warn here?

--
Best regards,
Vladimir
* now, @virtuozzo.com instead of @parallels.com. Sorry for this inconvenience.