[libvirt] [PATCH v2 4/4] qemu: Stop guest CPUs before creating a snapshot
This is currently needed because libvirt doesn't support qemu's RESUME
event. I have already implemented it but I need to test it thoroughly
since it has a great potential to break things when libvirt starts
seeing resume events that it wasn't seeing before.
---
src/qemu/qemu_driver.c | 37 ++++++++++++++++++++++++++++++++-----
1 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 2b286bb..d5776d6 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -6044,21 +6044,47 @@ cleanup:
/* The domain is expected to be locked and active. */
static int
-qemuDomainSnapshotCreateActive(struct qemud_driver *driver,
+qemuDomainSnapshotCreateActive(virConnectPtr conn,
+ struct qemud_driver *driver,
virDomainObjPtr *vmptr,
virDomainSnapshotObjPtr snap)
{
virDomainObjPtr vm = *vmptr;
qemuDomainObjPrivatePtr priv = vm->privateData;
- int ret;
+ bool resume = false;
+ int ret = -1;
if (qemuDomainObjBeginJobWithDriver(driver, vm) < 0)
return -1;
+ if (vm->state == VIR_DOMAIN_RUNNING) {
+ /* savevm monitor command pauses the domain emitting an event which
+ * confuses libvirt since it's not notified when qemu resumes the
+ * domain. Thus we stop and start CPUs ourselves.
+ */
+ if (qemuProcessStopCPUs(driver, vm) < 0)
+ goto cleanup;
+
+ resume = true;
+ if (!virDomainObjIsActive(vm)) {
+ qemuReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("guest unexpectedly quit"));
+ goto cleanup;
+ }
+ }
+
qemuDomainObjEnterMonitorWithDriver(driver, vm);
ret = qemuMonitorCreateSnapshot(priv->mon, snap->def->name);
qemuDomainObjExitMonitorWithDriver(driver, vm);
+cleanup:
+ if (resume && virDomainObjIsActive(vm) &&
+ qemuProcessStartCPUs(driver, vm, conn) < 0 &&
+ virGetLastError() == NULL) {
+ qemuReportError(VIR_ERR_OPERATION_FAILED, "%s",
+ _("resuming after snapshot failed"));
+ }
+
if (qemuDomainObjEndJob(vm) == 0)
*vmptr = NULL;
@@ -6103,18 +6129,19 @@ static virDomainSnapshotPtr
qemuDomainSnapshotCreateXML(virDomainPtr domain,
if (!(snap = virDomainSnapshotAssignDef(&vm->snapshots, def)))
goto cleanup;
+ snap->def->state = vm->state;
+
/* actually do the snapshot */
if (!virDomainObjIsActive(vm)) {
if (qemuDomainSnapshotCreateInactive(vm, snap) < 0)
goto cleanup;
}
else {
- if (qemuDomainSnapshotCreateActive(driver, &vm, snap) < 0)
+ if (qemuDomainSnapshotCreateActive(domain->conn, driver,
+ &vm, snap) < 0)
goto cleanup;
}
- snap->def->state = vm->state;
-
/* FIXME: if we fail after this point, there's not a whole lot we can
* do; we've successfully taken the snapshot, and we are now running
* on it, so we have to go forward the best we can
--
1.7.4.1