block_div
*e = to_dblock(block_div(se, cache->discard_block_size));
origin_blocks = block_div(origin_blocks, ca->block_size);
cache_size = block_div(cache_size, ca->block_size);
oblocks = block_div(oblocks, cache->sectors_per_block);
return to_dblock(block_div(from_oblock(oblock),