EXT2_ADDR_PER_BLOCK
#define EXT2_ADDR_PER_BLOCK_BITS(s) (log2(EXT2_ADDR_PER_BLOCK(s)))
if (logical_block < EXT2_ADDR_PER_BLOCK (SUPERBLOCK))
logical_block -= EXT2_ADDR_PER_BLOCK (SUPERBLOCK);
[logical_block & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)];
& (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)],
[logical_block & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)];