I have not looked, but I suspect the current cvs works or close to it,
and you'll need to update the kernel module.  There are now patches
for freebsd 4.8-stable, netbsd 1.6 and netbsd current (which lead you
to the current bits).

There have been some vnode changes in NetBSD (different locking rules
on lookup).  I don't know where OpenBSD is w.r.t. these.  But bringing
the kernel bits of openbsd up to realms should not be amazingly
difficult.  I would advise seeing if OpenSBD has Net-like or Free-like
VOP_LOOKUP rules and snarfing from the similar system.

        Greg Troxel <gdt_at_ir.bbn.com>