public static long getFileId(long blockId) {
    return createBlockId(getContainerId(blockId), getMaxSequenceNumber());
  }
@Test
  public void getFileId() {
    assertEquals(MAX_SEQUENCE_NUMBER, BlockId.getFileId(1L));
    assertEquals(MAX_SEQUENCE_NUMBER, BlockId.getFileId(20000L));
    assertEquals(MAX_SEQUENCE_NUMBER * 2 + 1, BlockId.getFileId(2 * MAX_SEQUENCE_NUMBER));
    assertEquals(2071264755711L, BlockId.getFileId(2071248101952L));
  }