On Thu, Jul 18, 2013 at 11:32:52AM -0600, Eric Blake wrote:
> On 07/18/2013 11:27 AM, Eric Blake wrote:
>
> >> if (!has_format) {
> >> - format = mode == NEW_IMAGE_MODE_EXISTING ? NULL :
> >> bs->drv->format_name;
> >> + format = mode == NEW_IMAGE_MODE_EXISTING ? NULL : "qcow2";
> >
> > Is this the right thing to do? Or should we do:
> >
> > if (!has_format) {
> > if (mode == NEW_IMAGE_MODE_EXISTING) {
> > format = NULL;
> > } else {
> > format = bs->drv->format_name ?: "qcow2";
> > }
> > }
> >
> > That is, I think we should default to doing a backup in the format given
> > by the original (what if the original is qed, which also supports
> > backing files), and only use qcow2 when there is no guidance whatsoever.
> >
> > But in practice, I don't care
>
> Well, I _DO_ care about one thing - make sure that the qapi-schema.json
> page accurately documents how this variable is defaulted for callers
> that don't care about the implications of omitting a format.
>
> Or we could simplify life by making 'format' mandatory for drive-backup;
> it was optional for 'drive-mirror' due to incremental implementation,
> but for 'drive-backup', we still have the opportunity to do things right
> from the first release.
Ah, I did make a doc change, I must have forgotten to add it.
I'm all for making format mandatory if that is ok with everyone. Maybe
that is the best solution.
Ian
