HEAD: no rootfs in jail

[Matthew Dillon]

:> > I don't remember when I started seeing this, but `df' doesn't show
:> > the rootfs from inside jail, but any other mountpoints are visible.
:> 
:> Correction: this is NOT specific to jail, but the same goes for chroot'ed
:> environment.
:
:I still got no clue for this, but the getfsstat(2) behavior is
:definitely wrong:
:

     I'll fix it.  It's the new namecache code.  chroot_visible_mnt()
     is not aware of the new way filesystems are glued together.

					-Matt