> I agree we have a problem with wedges in that they act as independent 
> devices as opposed to magic, free-form partitions. Thus detecting overlap 
> is harder; we don't have a central repository like we do with a partition 
> table. But that's arguably a bug of our wedge implementation. ;-)

dkwedge_add() has code to detect overlapped wedges.
isn't it what you are talking about?

YAMAMOTO Takashi