code: public boolean hasBlockMeta(long blockId) {
      for (StorageTier tier : mTiers) {
        for (StorageDir dir : tier.getStorageDirs()) {
          if (dir.hasBlockMeta(blockId)) {
            return true;
          }
        }
      }
      return false;
    }
docs: Checks if the storage has a given block.
  
  @param blockId the block id
  @return true if the block is contained, false otherwise