e2fsck 1.02 (I know, I know) does not detect or correct this problem,
but ext2fs doesn't like it. I don't know which of the two is considered
to have the bug, but one of them does.
Another problem (this is Linux 2.1.17) is that the process doing the
rmdir hangs, unkillably, after deleting the directory when this
happens. I'm not quite sure why yet. the directory is deleted,
but kill -9 doesn't do anything.
Anyway, I thought I'd tell someone.
-- -Colin