On Thu, Jun 11, 2015 at 12:21:31PM -0400, John Snow wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA256 > > > > On 06/11/2015 09:03 AM, Stefan Hajnoczi wrote: > > On Thu, Jun 11, 2015 at 01:19:24PM +0300, Vladimir > > Sementsov-Ogievskiy wrote: > >> On 10.06.2015 16:24, Stefan Hajnoczi wrote: > >>> On Wed, Jun 10, 2015 at 11:19:30AM +0300, Vladimir > >>> Sementsov-Ogievskiy wrote: > >>>> On 09.06.2015 20:03, Stefan Hajnoczi wrote: > >>>>> On Mon, Jun 08, 2015 at 06:21:19PM +0300, Vladimir > >>>>> Sementsov-Ogievskiy wrote: > >>>>>> @@ -166,6 +167,19 @@ the header extension data. Each > >>>>>> entry look like this: terminated if it has full length) > >>>>>> +== Dirty bitmaps == + +Dirty bitmaps is an optional > >>>>>> header extension. It provides a possibility of +storing > >>>>>> dirty bitmaps in qcow2 image. The fields are: + + > >>>>>> 0 - 3: nb_dirty_bitmaps + Number of > >>>>>> dirty bitmaps contained in the image > >>>>> Is there a maximum? > >>>> hmm. any proposals for this? > >>> 65535 seems practical. > >> > >> So, you suggest to reduce this field width to 2b? And additional > >> 2 bytes reserved field, to achieve 8b-alignment? > > > > No, I would leave it 32-bit but impose a little (which can be s/little/limit/ > > increased later if necessary). That's how nb_snapshots works too. > > > > Doesn't the code already limit the number of bitmaps via +#define > QCOW_MAX_DIRTY_BITMAPS 65536, from patch 2? It needs to be in the specification.