I proposed something like this a while ago, and now that I have a little
time to get some pending ideas done, I'd like to propose a ffs (and related
fs's) mount option that can turn on SVR4-style directory entry gid handling.
That is, files created in a directory have the owner's default gid, not the
gid of the directory, unless the directory itself is set-gid.

This would also involve adding appropriate set-gid bits to the base mtree
files, so that the proper places would work as expected if the option were
turned on for /.

Thoughts?

-- 
-- Todd Vierling (tv@pobox.com)