I've just finished a little tool for UFS filesystems.  It allows you to
grow and/or shrink a filesystem, assuming of course in the former case
that the partition is big enough to hold the new filesystem.  (I
haven't done the kernel hooks necessary to do this sort of thing live;
if the filesystem isn't unmounted, you're liable to come to grief, as
with anything that scribbles on raw disk.)  Growing is easy and fast;
little more is involved than creating the new cylinder groups.
Shrinking is of course slower, since it has to move all allocated data
blocks and inodes in the area being shrunk away, but I believe it does
this correctly, assuming of course there's enough free space to do so.
(It makes no attempt to optimize choice of places to put the moved
stuff; this might be a good project if someone's feeling ambitious.)

Is anyone interested in this?  And if so, should I send-pr it as an
enhancement, or put it up for ftp, or mail it out, or what?

					der Mouse

			    mouse@collatz.mcrcim.mcgill.edu