Knoppix still uses Reiserfs?
I can't imagine why a fsck tool would dive into payload like that - do you have some more information about this bug, as I can't find reference to it. Most of my residual reiserfs boxes are VM's themselves, so I'm unlikely to hit it, but some mitigation would be comforting.
Yep exactly that. The whole reason it did it was that it sometimes needed to recover from a corrupted b-tree but it leaves enough markers around that it could rebuild the b-tree by scanning all the blocks.
https://en.wikipedia.org/wiki/ReiserFS#fsck
I can't find a better link at the moment, the lkml link on wikipedia is dead and it's hard to search for, but at the time it was well known for this kind of bug.
EDIT:
Until I learned about that bug (the hard way at first) the ability of it to rebuild itself after a problem like that was actually incredibly useful, it'd recover really nicely from a bad disk, finding just what it could manage to find.
Unfortunately ... if you let it ride much above 80% disk usage for very long (or less time the fuller it got) it would fragment bad and the performance just fell off a cliff bad.