Re: Implementing Meta File information in Linux

Kristian Koehntopp (kris@koehntopp.de)
Wed, 2 Sep 1998 12:55:14 +0200


In netuse.lists.linux-kernel you write:
>This definitely is not possible in the directory fashion. Consider the
>normal (for the Mac, at any rate) approach to storing editing info
>(current line & col, for example) as a bit of information in the resource
>fork of a source code file. This works just about perfectly, and trivial
>programs simply ignore the resource information when they read from the
>data fork (which contains the desired source code, in the usual ASCII
>format). But in a directory system, there is no way to transparently
>change "foo.c" into "foo.c/data", at least not without some tricks in the
>VFS, or much smarter applications. (The closest we've ever come is the
>emacs & vi local-data sections, which is hardly transparent.)

Such things do not belong into the data files themselves. Can
you imagine what things like these are doing to your backup
concepts in a multi-user environment? Somebody touched a file
with an editor, did not change anything but the cursor position
in a ressource fork and the whole file goes to amanda the next
night...

Or what if I delete a user from my system. Imagine the system
administrator scanning the whole filesystem for ressource forks
where this particular user has stored now unneeded configuration
data and stripping all these forks from the respective files -
making changes to these files and forcing everything that user
*ever* touched on backup the next night (which is exactly the
opposite of the right thing to do, because I don't want to
backup what is going to stay in my system, but what I am going
to delete, just in case that user needs to be restored. Speaking
of restores: Can you imagine the administration nightmare that
is coming up, if you actually need to restore a user in your
system WITH ALL THE RESSOURCE FORKS BELONGING TO THAT USER IN
ALL FILES THAT THIS USER EVER TOUCHED? What if any of these
files have been modified or renamed in the meantime?)

And then there is the issue of permissions on files and on
forks. There is no way I would let an editor store data in any
fork of a file if that editor does not have write permission on
that file. The editor would then have to store that information
somewhere else, preferably in the users home directory, where
any information local to that user belongs anyway.

But then there is no need for resource forks storing such data
anyway - which is a correct observation, because there isn't.

Put user data in $HOME. Everything else is pain, great pain, NT
pain.

Kristian

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