Hi viq! Sorry, I have read your message right now (...I am not subscribed to this mailing list, I was looking at MARC as it seems the most up to date archive, and found your answer.)
Thanks a lot for the excellent reference you provided in your email. Indeed, it is a BSD disklabel related problem not a ffs's one. And it seems a serious one! Better thinking on using each drive on a single operating system from now... Again, thanks a lot for your feedback. Now I see that there are some issues, not related with ffs itself, that can make information in real risk if I continue sharing these filesystems between both OSes. Ok, I think that it is all clear now. I must decide what OS will have access to each drive. Thanks! Igor.