Re: FUSE merging?

Frank van Maarseveen
2005-07-03T13:50:19Z

On Sun, Jul 03, 2005 at 03:24:04PM +0200, Miklos Szeredi wrote:
> > > Hmm, do you mean returning different directory contents based on uid?
> >
> > http://clusternfs.sourceforge.net
> >
> > Don't ask me how this plays with the dcache.
>
> But here the decision on what to return is in the _server_.

It still means that name space invariancy cannot be guaranteed.

> There's
> nothing magic about that. It's as if it was N different servers for N
> different clients, only more effective.

Not entirely, there is a UID dependancy.

> I think what you call namespace invariance is basically true for all
> existing filesystems. There could be a filesystem which returns
> different directory contents based on whatever it wants, but it can't
> return a different "dentry" for the same name.

This is not what I mean. The directory contents itself must be identical
for every user. And every name must of course correspond with only one
dentry. That's name-space invariance IMO.

> > IMHO The namespace argument against FUSE is weak for multiple reasons. The
> > only variancy I see is when crossing the mount point. And that disappears
> > once EACCES is returned when non-ptraceable processes try to cross it.
>
> Yes, but still this is just a difference in permission, and not a
> difference in namespace.

Exactly. And such a difference in permission already exists for (sane)
networked file systems such as NFS with "squash_root" in effect on
the server.

--
Frank