EXT2_INODES_PER_BLOCK
>> log2 (EXT2_INODES_PER_BLOCK (SUPERBLOCK)));
((current_ino - 1) & (EXT2_INODES_PER_BLOCK (SUPERBLOCK) - 1)) *
EXT2_INODES_PER_BLOCK (SUPERBLOCK), EXT2_INODE_SIZE (SUPERBLOCK));