Avoid possible race condition in task submission and clean-up

Author: Fabricio Duarte

engine/orchestration/src/main/java/org/apache/cloudstack/engine/orchestration/StorageOrchestrator.java

@@ -111,7 +111,7 @@ public class StorageOrchestrator extends ManagerBase implements StorageOrchestra
 
     Integer numConcurrentCopyTasksPerSSVM = 2;
 
-    private final Map<Long, ThreadPoolExecutor> zoneExecutorMap = new ConcurrentHashMap<>();
+    private final Map<Long, ThreadPoolExecutor> zoneExecutorMap = new HashMap<>();
 
     @Override
     public String getConfigComponentName() {
@@ -357,7 +357,7 @@ protected Map<Long, Pair<Long, Long>> migrateAway(
         return storageCapacities;
     }
 
-    protected <T> Future<T> submit(Long zoneId, Callable<T> task) {
+    protected synchronized <T> Future<T> submit(Long zoneId, Callable<T> task) {
         if (!zoneExecutorMap.containsKey(zoneId)) {
             zoneExecutorMap.put(zoneId, new ThreadPoolExecutor(numConcurrentCopyTasksPerSSVM , numConcurrentCopyTasksPerSSVM,
                     30, TimeUnit.MINUTES, new MigrateBlockingQueue<>(numConcurrentCopyTasksPerSSVM)));