private void performShutdown() {
   if (myShutDown.compareAndSet(false, true)) {
     LOG.info("VFS dispose started");
     FSRecords.dispose();
     LOG.info("VFS dispose completed");
   }
 }
 private synchronized void performShutdown() {
   if (!myShutDown) {
     myShutDown = true;
     LOG.info("VFS dispose started");
     FSRecords.dispose();
     LOG.info("VFS dispose completed");
   }
 }