[fs which faked up /etc config files from a registry]

> Now this one is interesting to me.  One thing that I'd love to see is
> a well implemented user space filesystem (perhaps just a daemon that
> talks to the kernel's VFS layer).  For example, imagine an RCS filesystem
> built with a user space filesystem and the RCS commands.  When a file is
> opened, the daemon does an 'co -l' on the file.  When the file is closed,
> the daemon does a 'ci -u'.  It could probably even be extended to append
> version numbers to files ala VMS (IMO this is ugly as hell, but it is
> potentially useful in some cases).
> 
> In fact, it would be more useful to have a generic user space filesystem
> daemon that executes shell scripts to implement the VFS operations.  That
> way, we'd have a generic daemon that would be useful for experimenting
> with new filesystems without having to muck around in the kernel.  The
> FTP filesystem would be pretty trivial to implement with such a daemon.
> 
> Yes, this would be slow, insecure and open to all kinds of problems.  But
> it would be useful in some very limited cases and for experimentation.

Check out the kernel option "file-system PORTAL" and mount_portal. It's
a first-step implimentatation of what you describe.

Take care,

Bill