Thank you everybody.  I knew that it's possible to mount a filesystem
in other filesystem's directory tree.  I was tar'ring something into
/mnt and then accidently mounted another /mnt, so I thought everything
went to hell, but it didn't.  :)

BTW: did anybody mounted AmigaFFS on port-i386 for example _without_
crash/hang up?

Thanks, again.

	- Adam