code: public void recoverFileLease(final FileSystem fs, final Path p,
                                 Configuration conf)
      throws IOException {
      // lease recovery not needed for local file system case.
      if (!(fs instanceof DistributedFileSystem)) {
        return;
      }
      recoverDFSFileLease((DistributedFileSystem) fs, p, conf);
    }
docs: Recover the lease from HDFS, retrying multiple times.