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

[Kevin Wolf]

Am 04.08.2011 08:23, schrieb Hannes Reinecke:
> 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.

I think the policy is that you need to add a subsection anyway, even if
you just add a flag to an existing field.

Kevin