Comment 23 for bug 8585

That's interesting, nuking mtab first makes the mount succeed on both the ext3
and xfs boxes. But they're still remaining as "unknown" on boot.

Reading checkroot.sh, the file certainly should be empty before the mount
option. So I had a little fiddle, and watch out, your mind is about to blow out
of your ears:

This is what just worked for both you and I ...

descent /etc# cat mtab
descent /etc# mount -f -o defaults /
descent /etc# cat mtab
/dev/hda3 / ext3 rw,errors=remount-ro 0 0

I added the -o defaults bit just to be a bit more inline with checkroot.sh, it
passes -o $rootopts rather than remount (the -f means it makes no difference
anyway). So that works. But that's not *quite* what checkroot.sh does, it also
passes $fstabroot

descent /etc# :> mtab
descent /etc# cat mtab
descent /etc# mount -f -o defaults /dev/hda3 /
descent /etc# cat mtab
/dev/hda3 / unknown rw 0 0

So that's what makes it fail, by giving the partition there it stops it from
actually guessing the partition type.