unix filename/patch substitution functionality?

[Teus Hagen]

Probably this request/proposal has already been popped up before.
If so my excuses, as I follow this e-mail list just very shortly.

In reality I was looking for a so called "transludent" (spelling error?) filesystem support.
Which is: parts of changes in a (sub)tree of the filesystem are
remembered and only availabe e.g. to one user. It could be of use
in transaction systems?

One need for this functionality can be explained by a situation where
a path/file is changed for one user but will remain invisible for
another user: the path/file one/two/three.txt is translated to 
one/xyz/%u/my_three.txt (effectively to one/xyz/user_name/my_three.txt
(just to show the functionality).
This could be done by string substitution rules.
The %u should be translated to user_name by the convertion of the smb.conf
to the particular user logon session. In this
way this file normally somewhere in the filesystem will appear only
for one particular user in his/her home subtree.

This example does not (yet) describe the read one file and write another
file functionality. But it gives you an idea.

Why is there a need for this?
Many DOS/Windows applications are installed in such a way that there is a need
to have some files write accessable for the world. In this way
your filesystem is looking like a swiss chees with lots of security holes.
It will going to smell well after a while.

The mangling name functionality will not solve this. 
In my humble naive
opinion this function can be easily build into smbd/filename.c.
But maybe (it is dangerous code there) I'm overlooking something?

I would appriciate comments for this "new" (?) function.

Thanks

teus