[libvirt] [PATCHv2 07/26] snapshot: track current snapshot across restarts

[Eric Blake]

On 08/15/2011 05:33 PM, Eric Blake wrote:
> Audit all changes to the qemu vm->current_snapshot, and make them
> update the saved xml file for both the previous and the new
> snapshot, so that there is always at most one snapshot with
> <active>1</active>  in the xml, and that snapshot is used as the
> current snapshot even across libvirtd restarts.
>
>       if (snap == vm->current_snapshot) {
>           if (snap->def->parent) {
>               parentsnap = virDomainSnapshotFindByName(&vm->snapshots,
>                                                        snap->def->parent);
>               if (!parentsnap) {
> -                qemuReportError(VIR_ERR_NO_DOMAIN_SNAPSHOT,
> -                                _("no domain snapshot parent with matching name '%s'"),
> -                                snap->def->parent);
> -                goto cleanup;
> +                VIR_WARN("missing parent snapshot matching name '%s'",
> +                         snap->def->parent);
> +            } else {
> +                parentsnap->def->current = true;
> +                if (qemuDomainSnapshotWriteMetadata(vm, snap,
> +                                                    driver->snapshotDir)<  0) {

It helps to write to the correct file.  Squash this in:

diff --git i/src/qemu/qemu_driver.c w/src/qemu/qemu_driver.c
index 76c5549..f3b5fd8 100644
--- i/src/qemu/qemu_driver.c
+++ w/src/qemu/qemu_driver.c
@@ -8995,7 +8995,7 @@ static int qemuDomainSnapshotDiscard(struct 
qemud_driver *driver,
                           snap->def->parent);
              } else {
                  parentsnap->def->current = true;
-                if (qemuDomainSnapshotWriteMetadata(vm, snap,
+                if (qemuDomainSnapshotWriteMetadata(vm, parentsnap,
 
driver->snapshotDir) < 0) {
                      VIR_WARN("failed to set parent snapshot '%s' as 
current",
                               snap->def->parent);

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org