CLOUDSTACK-10222: Clean snaphosts from primary storage when taking new (#2398)

When user creates a snapshot (manual or recurring), snapshot remains on
the primary storage, even if the snapshot is transferred successfully to
secondary storage. This is causing issues because XenServer can only hold
a limited number of snapshots in its VDI chain, preventing the user from
creating new snapshots after some time, when too many old snapshots are
present on the primary storage.

Author: khos2ow

plugins/hypervisors/xenserver/src/com/cloud/hypervisor/xenserver/resource/XenServerStorageProcessor.java

@@ -1071,7 +1071,7 @@ protected boolean destroySnapshotOnPrimaryStorageExceptThis(final Connection con
         return false;
     }
 
-    private boolean destroySnapshotOnPrimaryStorage(final Connection conn, final String lastSnapshotUuid) {
+    protected boolean destroySnapshotOnPrimaryStorage(final Connection conn, final String lastSnapshotUuid) {
         try {
             final VDI snapshot = getVDIbyUuid(conn, lastSnapshotUuid);
             if (snapshot == null) {

plugins/hypervisors/xenserver/src/com/cloud/hypervisor/xenserver/resource/Xenserver625StorageProcessor.java

@@ -559,12 +559,12 @@ public Answer backupSnapshot(final CopyCommand cmd) {
                     physicalSize = Long.parseLong(tmp[1]);
                     finalPath = folder + File.separator + snapshotBackupUuid + ".vhd";
                 }
-
-                final String volumeUuid = snapshotTO.getVolume().getPath();
-
-                destroySnapshotOnPrimaryStorageExceptThis(conn, volumeUuid, snapshotUuid);
             }
 
+            // remove every snapshot except this one from primary storage
+            final String volumeUuid = snapshotTO.getVolume().getPath();
+            destroySnapshotOnPrimaryStorageExceptThis(conn, volumeUuid, snapshotUuid);
+
             final SnapshotObjectTO newSnapshot = new SnapshotObjectTO();
             newSnapshot.setPath(finalPath);
             newSnapshot.setPhysicalSize(physicalSize);
@@ -577,12 +577,13 @@ public Answer backupSnapshot(final CopyCommand cmd) {
             s_logger.info("New snapshot physical utilization: "+physicalSize);
 
             return new CopyCmdAnswer(newSnapshot);
-        } catch (final Types.XenAPIException e) {
-            details = "BackupSnapshot Failed due to " + e.toString();
-            s_logger.warn(details, e);
         } catch (final Exception e) {
-            details = "BackupSnapshot Failed due to " + e.getMessage();
+            final String reason = e instanceof Types.XenAPIException ? e.toString() : e.getMessage();
+            details = "BackupSnapshot Failed due to " + reason;
             s_logger.warn(details, e);
+
+            // remove last bad primary snapshot when exception happens
+            destroySnapshotOnPrimaryStorage(conn, snapshotUuid);
         }
 
         return new CopyCmdAnswer(details);