qemu: Kill QEMU process if Prepare phase fails

Some failure paths in qemuMigrationPrepareAny forgot to kill the just
started QEMU process. This patch fixes this by combining 'stop' and
'endjob' label into a new label 'stopjob'. This name was chosen to avoid
confusion with the most common semantics of 'endjob'. Normally, 'endjob'
is always called at the end of an API to stop the job we entered at the
beginning. In qemuMigrationPrepareAny we only want to stop the job in
failure path; on success we need to carry the job over to the Finish
phase.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

src/qemu/qemu_migration.c

@@ -3522,7 +3522,7 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
         (pipe(dataFD) < 0 || virSetCloseExec(dataFD[1]) < 0)) {
         virReportSystemError(errno, "%s",
                              _("cannot create pipe for tunnelled migration"));
-        goto endjob;
+        goto stopjob;
     }
 
     virObjectUnref(priv->qemuCaps);
@@ -3530,11 +3530,11 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
                                                 vm->def->emulator,
                                                 vm->def->os.machine);
     if (!priv->qemuCaps)
-        goto endjob;
+        goto stopjob;
 
     if (!(migrateFrom = qemuMigrationPrepareIncoming(vm, tunnel, protocol,
                                                      listenAddress, port)))
-        goto endjob;
+        goto stopjob;
 
     /* Start the QEMU daemon, with the same command-line arguments plus
      * -incoming $migrateFrom
@@ -3545,14 +3545,14 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
                          VIR_QEMU_PROCESS_START_PAUSED |
                          VIR_QEMU_PROCESS_START_AUTODESTROY) < 0) {
         virDomainAuditStart(vm, "migrated", false);
-        goto endjob;
+        goto stopjob;
     }
 
     if (tunnel) {
         if (virFDStreamOpen(st, dataFD[1]) < 0) {
             virReportSystemError(errno, "%s",
                                  _("cannot pass pipe for tunnelled migration"));
-            goto stop;
+            goto stopjob;
         }
         dataFD[1] = -1; /* 'st' owns the FD now & will close it */
     }
@@ -3560,17 +3560,17 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
     if (qemuMigrationSetCompression(driver, vm,
                                     flags & VIR_MIGRATE_COMPRESSED,
                                     QEMU_ASYNC_JOB_MIGRATION_IN) < 0)
-        goto stop;
+        goto stopjob;
 
     if (STREQ_NULLABLE(protocol, "rdma") &&
         virProcessSetMaxMemLock(vm->pid, vm->def->mem.hard_limit << 10) < 0) {
-        goto stop;
+        goto stopjob;
     }
 
     if (qemuMigrationSetPinAll(driver, vm,
                                flags & VIR_MIGRATE_RDMA_PIN_ALL,
                                QEMU_ASYNC_JOB_MIGRATION_IN) < 0)
-        goto stop;
+        goto stopjob;
 
     if (mig->lockState) {
         VIR_DEBUG("Received lockstate %s", mig->lockState);
@@ -3593,7 +3593,7 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
         if (qemuMigrationStartNBDServer(driver, vm, listenAddress,
                                         nmigrate_disks, migrate_disks) < 0) {
             /* error already reported */
-            goto endjob;
+            goto stopjob;
         }
         cookieFlags |= QEMU_MIGRATION_COOKIE_NBD;
     }
@@ -3608,7 +3608,7 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
     }
 
     if (qemuDomainCleanupAdd(vm, qemuMigrationPrepareCleanup) < 0)
-        goto endjob;
+        goto stopjob;
 
     if (!(flags & VIR_MIGRATE_OFFLINE)) {
         virDomainAuditStart(vm, "migrated", true);
@@ -3647,12 +3647,13 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
     virNWFilterUnlockFilterUpdates();
     return ret;
 
- stop:
-    virDomainAuditStart(vm, "migrated", false);
-    qemuProcessStop(driver, vm, VIR_DOMAIN_SHUTOFF_FAILED,
-                    VIR_QEMU_PROCESS_STOP_MIGRATED);
+ stopjob:
+    if (vm->def->id != -1) {
+        virDomainAuditStart(vm, "migrated", false);
+        qemuProcessStop(driver, vm, VIR_DOMAIN_SHUTOFF_FAILED,
+                        VIR_QEMU_PROCESS_STOP_MIGRATED);
+    }
 
- endjob:
     qemuMigrationJobFinish(driver, vm);
     goto cleanup;
 }