better type safety and KNF.

better type safety and KNF.

Because ext2fs has only 32-bit inode numbers, use ufsino_t as in FFS.
Disk blocks are u_int32_t as well, because we don't support the 64BIT flag.
When we do, there's going to be a lot more going on than just daddr_t.

While there, add some journaling-related bits into the superblock to play with.

ok guenther