Faster mkfs.ext3

[David Shaw <dshaw jabberwocky com>]

I'm currently working with a testing system that involves running
mkfs.ext3 on some pretty large devices on a regular basis.  This is
getting fairly painful, and I was wondering if there was some way to
speed this up.  Understood that the end result might be a filesystem
that has less of a safety factor (say, fewer superblock backups) but
the tradeoff might be worth it in this case.

David