So should I drop the "block: rename *_invalidate_cache_* to
*_post_incoming_migration_*" commit ?
On Tue, Mar 20, 2012 at 4:42 PM, Stefan Hajnoczi <stefa...@gmail.com> wrote:
> On Tue, Mar 06, 2012 at 06:32:27PM +0100, Benoît Canet wrote:
> > @@ -1529,6 +1529,19 @@ static int
> bdrv_qed_change_backing_file(BlockDriverState *bs,
> > return ret;
> > }
> >
> > +static void bdrv_qed_check_if_needed(BlockDriverState *bs)
> > +{
> > + /* close the block device if the verification fail */
> > + if (check_image_if_needed(bs)) {
> > + bdrv_close(bs);
> > + }
>
> We open the image for incoming migration while the VM is still running.
> That means the metadata and header can still change before migration
> switchover. So we need to drop everything we know about this image and
> start from scratch.
>
> qcow2 does it like this:
>
> qcow2_close(bs);
> memset(s, 0, sizeof(BDRVQcowState));
> qcow2_open(bs, flags);
>
> We should do something similar so that the QED header is re-read. This
> probably means check_image_if_needed() doesn't need to be factored out
> of qed_open().
>
> (Note that the underlying file and BlockDriverState don't get reopened,
> we're simply reinitializing the QED/QCOW2 image format layer here.)
>
> Stefan
>
