code: public void removeBlockMeta(BlockMeta blockMeta) throws BlockDoesNotExistException {
      Preconditions.checkNotNull(blockMeta, "blockMeta");
      long blockId = blockMeta.getBlockId();
      BlockMeta deletedBlockMeta = mBlockIdToBlockMap.remove(blockId);
      if (deletedBlockMeta == null) {
        throw new BlockDoesNotExistException(ExceptionMessage.BLOCK_META_NOT_FOUND, blockId);
      }
      reclaimSpace(blockMeta.getBlockSize(), true);
    }
docs: Removes a block from this storage dir.
  
  @param blockMeta the metadata of the block
  @throws BlockDoesNotExistException if no block is found