code: public void setPermission(String src, FsPermission permission
                              ) throws IOException {
      checkOpen();
      clearFileStatusCache();
      
      try {
        namenode.setPermission(src, permission);
      } catch(RemoteException re) {
        throw re.unwrapRemoteException(AccessControlException.class,
                                       FileNotFoundException.class);
      }
    }
docs: Set permissions to a file or directory.
  @param src path name.
  @param permission
  @throws <code>FileNotFoundException</code> is file does not exist.