code: private void prepareRootFhAndNfsPort() throws IOException {
  
          if (!_prepareLock.tryLock()) {
              return;
          }
  
          try {
              _port = getNfsPortFromServer();
              _rpcWrapper.setPort(_port);
              _rootFileHandle = lookupRootHandle();
          } finally {
              _prepareLock.unlock();
          }
      }
docs: Query the port and root file handle for NFS server.
  @throws IOException