Re: [Qemu-devel] [PATCH V12 06/18] block: add check for VM snapshot in bdrv_query_snapshot_info_list()

[Wenchao Xia]

于 2013-4-18 4:52, Eric Blake 写道:
> On 04/13/2013 02:56 AM, Wenchao Xia wrote:
> >    This patch adds a parameter to tell whether return valid snapshots
> > for whole VM only.
> >    Note that the snapshot check logic is copied from do_info_snapshots(),
> > which is different with load_vmstate() and will be changed in next patch.
> >
> > Signed-off-by: Wenchao Xia <address@hidden>
> > Reviewed-by: Eric Blake <address@hidden>
> > Reviewed-by: Kevin Wolf <address@hidden>
> > ---
>
> > +
> > +    /* Check logic is connected with load_vmstate():
> > +       Only check the devices that can snapshot, other devices that can't
> > +       take snapshot, for example, readonly ones, will be ignored in
> > +       load_vmstate(). */
> > +    while ((bs1 = bdrv_next(bs1))) {
> > +        if (bs1 != bs && bdrv_can_snapshot(bs1)) {
> > +            ret = bdrv_snapshot_find(bs1, sn_info, sn->id_str, NULL);
>
> This says for a snapshot to be consistent, all block devices must share
> the same id but can have different names.  Is that really true?  Or is
> it backwards from reality?  If snapshot ids allocated incrementally per
> block device, can I use hotplug to create a situation where I have a VM
> with two disks
  OK, it would check both.

> where the existing HMP 'loadvm B' should load the snapshot named 'B'
> from both disks, regardless of the different number, and where snapshot
> 'A' is inconsistent unless disk b is hot-unplugged?


--
Best Regards

Wenchao Xia