> While at USENIX, I saw the _correct_ way to do a union FS. It was done
> as a pre-loaded shared library, and because of that it was a lot more
> flexible than any kernel implementation would ever be (it was not
> limited to the unix mount global state: it was used more like Plan-9's
> dynamic per-process mounting).
You mean by (effectively) wrapping the libc file I/O functions? This seems
feasible, but I wonder about coherency and race conditions with each process
doing it's own "inheritance", and how the information on inheriting mounts
would be disseminated. (I suppose a deamon using IPC could resolve a lot
of this.)
> After having seen that, I don't think I necessarily would even want a
> kernel implementation. It simply was so much better done in user
> space..
If my guess is right, it sounds like it has it's own problems, but even so it
must be less painful then doing it in kernel space.
> The stuff had been done by Dave Korn (or Korn shell fame (and don't
> flame me if his first name isn't "Dave", my mind is going)) at AT&T.
> Damn, but I can't remember his email address..
>
> Linus
-- Kenneth Albanowski (kjahds@kjahds.com, CIS: 70705,126)