Address Joao reviews

Author: hsato03

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

@@ -402,8 +402,10 @@ private void migrateKvmIncrementalSnapshotChain(DataObject chosenFileForMigratio
                 migrateBetweenSecondaryStoragesCmd.setWait(StorageManager.AgentMaxDataMigrationWaitTime.valueIn(host.getClusterId()));
                 answer = (MigrateBetweenSecondaryStoragesCommandAnswer) agentManager.send(host.getId(), migrateBetweenSecondaryStoragesCmd);
                 if (answer == null || !answer.getResult()) {
-                    logger.warn("Unable to migrate snapshots [{}].", snapshotChain);
-                    throw new CloudRuntimeException("Unable to migrate KVM incremental snapshots to another secondary storage");
+                    if (answer != null) {
+                        logger.warn(answer.getDetails());
+                    }
+                    throw new CloudRuntimeException("Unable to migrate KVM incremental snapshots to another secondary storage.");
                 }
             } catch (final OperationTimedoutException | AgentUnavailableException e) {
                 throw new CloudRuntimeException("Error while migrating KVM incremental snapshot chain. Check the logs for more information.", e);
@@ -416,7 +418,6 @@ private void migrateKvmIncrementalSnapshotChain(DataObject chosenFileForMigratio
         });
     }
 
-
     private void updateSnapshotsReference(DataStore destDataStore, MigrateBetweenSecondaryStoragesCommandAnswer answer) {
         for (Pair<Long, String> snapshotIdAndUpdatedCheckpointPath : answer.getMigratedResources()) {
             Long snapshotId = snapshotIdAndUpdatedCheckpointPath.first();

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/wrapper/LibvirtMigrateSnapshotsBetweenSecondaryStoragesCommandWrapper.java

@@ -76,29 +76,37 @@ public Answer execute(MigrateSnapshotsBetweenSecondaryStoragesCommand command, L
         boolean parentSnapshotWasMigrated = false;
         Set<Long> snapshotsIdToMigrate = command.getSnapshotsIdToMigrate();
 
+        DataTO currentSnapshot = null;
+
         try {
             for (DataTO snapshot : command.getSnapshotChain()) {
+                currentSnapshot = snapshot;
                 imagePoolUrl = snapshot.getDataStore().getUrl();
                 imagePool = storagePoolManager.getStoragePoolByURI(imagePoolUrl);
                 imagePools.add(imagePool);
 
                 String resourceCurrentPath = imagePool.getLocalPathFor(snapshot.getPath());
 
                 if (imagePoolUrl.equals(srcDataStore.getUrl()) && snapshotsIdToMigrate.contains(snapshot.getId())) {
+                    logger.debug("Migrating snapshot [{}] to destination storage pool [{}].", snapshot.getId(), destImagePool.getUuid());
                     parentSnapshotPath = copyResourceToDestDataStore(snapshot, resourceCurrentPath, destImagePool, parentSnapshotPath);
                     parentSnapshotWasMigrated = true;
+                    logger.debug("Snapshot [{}] migrated successfully. New parent path: [{}]", snapshot.getId(), parentSnapshotPath);
                 } else {
                     if (parentSnapshotWasMigrated) {
+                        logger.debug("Rebasing snapshot [{}] to new parent path: [{}]", snapshot.getId(), parentSnapshotPath);
                         parentSnapshotPath = rebaseResourceToNewParentPath(resourceCurrentPath, parentSnapshotPath);
                     } else {
+                        logger.debug("Skipping migration/rebase for snapshot [{}]. Keeping current path.", snapshot.getId());
                         parentSnapshotPath = resourceCurrentPath;
                     }
                     parentSnapshotWasMigrated = false;
                 }
             }
+            logger.info("Successfully completed migrating snapshot chain [{}].", command.getSnapshotChain());
         }  catch (LibvirtException | QemuImgException e) {
             logger.error("Exception while migrating snapshots [{}] to secondary storage [{}] due to: [{}].", command.getSnapshotChain(), imagePool, e.getMessage(), e);
-            return new MigrateBetweenSecondaryStoragesCommandAnswer(command, false, "Migration of snapshots between secondary storages failed", resourcesToUpdate);
+            return new MigrateBetweenSecondaryStoragesCommandAnswer(command, false, String.format("Unable to migrate snapshot with ID [%s].", currentSnapshot.getId()), resourcesToUpdate);
         } finally {
             for (String file : filesToRemove) {
                 removeResourceFromSourceDataStore(file);