> I've wondered if there's enough context information > that the fs driver could "fake" per-process mount points > directly.
A totally uneducated shot in the dark: would having a userspace "mount" command that creates a private namespace (vaguely what you describe in your note) not be a good starting point? I'd use /ns rather than /n as the root, but that's really a small thing. Unfortunately, I have no idea (yet) of the machinery provided by Linux to construct private namespaces. And I am not aware of any equivalent work in the NetBSD world. ++L
