On 11/19/2012 09:06 AM, Peter Krempa wrote: > Some hypervisors require a respawn of the hypervisor to allow reverting > to some snapshot states. This patch adds flag to remove the default > safe approach to not allow this. When this flag is specified the > hypervisor driver should re-emit events to allow management apps to > reconnect. > > This flag is meant as a lesser way to enforce the restart of the > hypervisor, that is a fairly common possibility compared to other > meanings that the existing force flag has. > --- > Force now selects this flag and this flag can be used with internal snapshots > too. > ---
> @@ -12129,7 +12129,11 @@ static int > qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot, > > virCheckFlags(VIR_DOMAIN_SNAPSHOT_REVERT_RUNNING | > VIR_DOMAIN_SNAPSHOT_REVERT_PAUSED | > - VIR_DOMAIN_SNAPSHOT_REVERT_FORCE, -1); > + VIR_DOMAIN_SNAPSHOT_REVERT_FORCE | > + VIR_DOMAIN_SNAPSHOT_REVERT_RESPAWN, -1); > + > + if (flags & VIR_DOMAIN_SNAPSHOT_REVERT_FORCE) > + flags |= VIR_DOMAIN_SNAPSHOT_REVERT_RESPAWN; Up to here looks fine. > > /* We have the following transitions, which create the following events: > * 1. inactive -> inactive: none > @@ -12249,7 +12253,7 @@ static int > qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot, Hmm, this is incomplete. Earlier, inside a VIR_DOMAIN_SNAPSHOT_REVERT_FORCE check, we have: if (virDomainObjIsActive(vm) && !(snap->def->state == VIR_DOMAIN_RUNNING || snap->def->state == VIR_DOMAIN_PAUSED) && (flags & (VIR_DOMAIN_SNAPSHOT_REVERT_RUNNING | VIR_DOMAIN_SNAPSHOT_REVERT_PAUSED))) { virReportError(VIR_ERR_SNAPSHOT_REVERT_RISKY, "%s", _("must respawn qemu to start inactive snapshot")); goto cleanup; which should be converted to the new flag. > if (config && !virDomainDefCheckABIStability(vm->def, config)) { > virErrorPtr err = virGetLastError(); > > - if (!(flags & VIR_DOMAIN_SNAPSHOT_REVERT_FORCE)) { > + if (!(flags & VIR_DOMAIN_SNAPSHOT_REVERT_RESPAWN)) { > /* Re-spawn error using correct category. */ I think this one is correct, though. > @@ -2830,6 +2830,10 @@ I<--running> or I<--paused> flags when reverting to a > disk snapshot of a > transient domain. The I<--stopped> flag cannot be used on snapshots > of transient domains. > > +Some snapshot revert approaches may require a respawn of the hypervisor > +process. This is not allowed by default. You may specify I<--allow-respawn> > +to override this limit. It might be worth mentioning that --force implies --allow-respawn (that is, --force is a supserset of --allow-respawn, in that it can force situations that --allow-respawn will not). -- Eric Blake ebl...@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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