BLOCK_ROUND_UP
uint64 blockCount = BLOCK_ROUND_UP(size) / B_PAGE_SIZE;
uint64 newBlockCount = BLOCK_ROUND_UP(newSize) / B_PAGE_SIZE;
uint64 neededBlockCount = BLOCK_ROUND_UP((uint64)size + inBlockOffset)
uint64 fileBlockCount = BLOCK_ROUND_UP(Size()) / B_PAGE_SIZE;