Re: [Qemu-devel] [PATCH v2 27/45] scsi-disk: Preserve tray state on migration

[Paolo Bonzini]

On 08/04/2011 08:23 AM, Hannes Reinecke wrote:
> On 08/03/2011 03:08 PM, Markus Armbruster wrote:
> > Breaks migration of qdevs "scsi-cd" and legacy "scsi-disk" to older
> > versions. We normally use subsections to avoid that. Not possible
> > here, because we don't have a section to begin with. Too bad.
> >
> > Signed-off-by: Markus Armbruster<address@hidden>
> > ---
> > hw/scsi-disk.c | 35 +++++++++++++++++++++++++++++++++++
> > 1 files changed, 35 insertions(+), 0 deletions(-)
> >
> > diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
> > index f223de6..04e0a77 100644
> > --- a/hw/scsi-disk.c
> > +++ b/hw/scsi-disk.c
> > @@ -1301,6 +1301,39 @@ static int scsi_disk_initfn(SCSIDevice *dev)
> > return scsi_initfn(dev, scsi_type);
> > }
> >
> > +static int scsi_cd_post_load(void *opaque, int version_id)
> > +{
> > + SCSIDiskState *s = opaque;
> > +
> > + bdrv_eject(s->bs, s->tray_open);
> > + bdrv_lock_medium(s->bs, s->tray_locked);
> > + return 0;
> > +}
> > +
> > +static const VMStateDescription vmstate_scsi_cd = {
> > + .name = "scsi-cd",
> > + .version_id = 0,
> > + .minimum_version_id = 0,
> > + .post_load = scsi_cd_post_load,
> > + .fields = (VMStateField[]) {
> > + VMSTATE_BOOL(tray_open, SCSIDiskState),
> > + VMSTATE_BOOL(tray_locked, SCSIDiskState),
> > + VMSTATE_END_OF_LIST()
> > + }
> > +};
> > +
> > +static const VMStateDescription vmstate_scsi_disk = {
> > + .name = "scsi-disk",
> > + .version_id = 0,
> > + .minimum_version_id = 0,
> > + .post_load = scsi_cd_post_load,
> > + .fields = (VMStateField[]) {
> > + VMSTATE_BOOL(tray_open, SCSIDiskState),
> > + VMSTATE_BOOL(tray_locked, SCSIDiskState),
> > + VMSTATE_END_OF_LIST()
> > + }
> > +};
> > +
> And again; if we had just one 'flags' value we would have to save only
> one variable. And wouldn't need to touch this one for future states.

Agreed, but we have time until 0.16 to fix this.  I plan to migrate more 
stuff (unit attention state, for one), I'll take care of this too.

Paolo