Volume migration (#4043)

* Update AncientDataMotionStrategy.java

fix When secondary storage usage is> 90%, VOLUME migration across primary storage will cause the migration to fail and lose VOLUME

* Update AncientDataMotionStrategy.java

Volume is migrated across Primary storage. If no secondary storage is available(Or used capacity> 90% ), the migration is canceled.
Before modification, if secondary storage cannot be found, copyVolumeBetweenPools return NUll

copyAsync considers answer = null to be a sign of successful task execution, so it deletes the VOLUME on the old primary storage. This is the root cause of data loss, because VOLUME did not perform the migration at all.

* code in comment removed

Co-authored-by: div8cn <35140268+div8cn@users.noreply.github.com>
Co-authored-by: Daan Hoogland <dahn@onecht.net>
diff --git a/engine/storage/datamotion/src/main/java/org/apache/cloudstack/storage/motion/AncientDataMotionStrategy.java b/engine/storage/datamotion/src/main/java/org/apache/cloudstack/storage/motion/AncientDataMotionStrategy.java
index bc49a53..a5b01c7 100644
--- a/engine/storage/datamotion/src/main/java/org/apache/cloudstack/storage/motion/AncientDataMotionStrategy.java
+++ b/engine/storage/datamotion/src/main/java/org/apache/cloudstack/storage/motion/AncientDataMotionStrategy.java
@@ -330,8 +330,9 @@
             // directly to s3
             ImageStoreEntity imageStore = (ImageStoreEntity)dataStoreMgr.getImageStoreWithFreeCapacity(destScope.getScopeId());
             if (imageStore == null || !imageStore.getProtocol().equalsIgnoreCase("nfs") && !imageStore.getProtocol().equalsIgnoreCase("cifs")) {
-                s_logger.debug("can't find a nfs (or cifs) image store to satisfy the need for a staging store");
-                return null;
+                String errMsg = "can't find a nfs (or cifs) image store to satisfy the need for a staging store";
+                Answer answer = new Answer(null, false, errMsg);
+                return answer;
             }
 
             DataObject objOnImageStore = imageStore.create(srcData);