lxc: Add destroy support for suspended domains

Destroying a suspended domain needs special action.
We cannot simply terminate all process because they are frozen.
Do deal with that we send them SIGKILL and thaw them.
Upon wakeup the process sees the pending signal and dies immediately.
Signed-off-by: NRichard Weinberger <richard@nod.at>

src/lxc/lxc_process.c

@@ -697,6 +697,30 @@ int virLXCProcessStop(virLXCDriverPtr driver,
         VIR_FREE(vm->def->seclabels[0]->imagelabel);
     }
 
+    /* If the LXC domain is suspended we send all processes a SIGKILL
+     * and thaw them. Upon wakeup the process sees the pending signal
+     * and dies immediately. It is guaranteed that priv->cgroup != NULL
+     * here because the domain has aleady been suspended using the
+     * freezer cgroup.
+     */
+    if (reason == VIR_DOMAIN_SHUTOFF_DESTROYED &&
+        virDomainObjGetState(vm, NULL) == VIR_DOMAIN_PAUSED) {
+        if (virCgroupKillRecursive(priv->cgroup, SIGKILL) <= 0) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("Unable to kill all processes"));
+            return -1;
+        }
+
+        if (virCgroupSetFreezerState(priv->cgroup, "THAWED") < 0) {
+            virReportError(VIR_ERR_OPERATION_FAILED, "%s",
+                           _("Unable to thaw all processes"));
+
+            return -1;
+        }
+
+        goto cleanup;
+    }
+
     if (priv->cgroup) {
         rc = virCgroupKillPainfully(priv->cgroup);
         if (rc < 0)
@@ -716,6 +740,7 @@ int virLXCProcessStop(virLXCDriverPtr driver,
         }
     }
 
+cleanup:
     virLXCProcessCleanup(driver, vm, reason);
 
     return 0;