On Wed, May 22, 2013 at 11:53:44AM +0200, Kevin Wolf wrote:
> Am 16.05.2013 um 10:36 hat Stefan Hajnoczi geschrieben:
> > + proto_drv = bdrv_find_protocol(target);
> > + if (!proto_drv) {
> > + error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
> > + return;
> > + }
>
> I see that other block job commands are doing the same, but there are
> two things unclear for me about this:
>
> 1. Shouldn't bdrv_img_create() and/or bdrv_open() already return an error
> if the protocol can't be found? The error check is the only thing
> that proto_drv is used for.
>
> 2. Why do we complain about a wrong _format_ here? If I ask for a qcow2
> image called foo:bar.qcow2, qemu won't find the protocol "foo" and
> complain that qcow2 is an invalid format.
You are right. It doesn't seem necessary, we'll get an error message
later from bdrv_open() or bdrv_img_create().
Will drop in the next revision.
> > +
> > + bdrv_get_geometry(bs, &size);
> > + size *= 512;
>
> I was going to suggest BDRV_SECTOR_SIZE at first, but...
>
> Why not use bdrv_getlength() in the first place if you need it in bytes
> anyway? As a nice bonus you would get -errno instead of size 0 on
> failure.
Yes. Will fix and update qmp_drive_mirror() too.
> > + if (mode != NEW_IMAGE_MODE_EXISTING) {
> > + assert(format && drv);
> > + bdrv_img_create(target, format,
> > + NULL, NULL, NULL, size, flags, &local_err, false);
> > + }
> > +
> > + if (error_is_set(&local_err)) {
> > + error_propagate(errp, local_err);
> > + return;
> > + }
> > +
> > + target_bs = bdrv_new("");
> > + ret = bdrv_open(target_bs, target, NULL, flags, drv);
> > +
> > + if (ret < 0) {
>
> Why the empty line between bdrv_open and checking its return value?
A dramatic pause, to build up suspense :).
Will drop in the next revision and update qmp_drive_mirror() too.
