It's changed a bit from Knoppix 4, 5, and 5.1. Basically I boot into
runlevel 3 and get lvm started either through lvmchage -a (I think)
or running the init script. This will activate any lvm partitions
that Knoppix can find, but doesn't mount them.
then I can use e2fsck (or equivalent) to fixup or resize any lvm
partitions.