Coda File System

Re: coda looses group ownership

From: <>
Date: Mon, 26 Feb 2007 21:13:03 +0100
On Mon, Feb 26, 2007 at 07:57:21PM +0100, Enrico Weigelt wrote:
> no matter what I do, coda looses the file's group id.

Hi Enrico,

unix mode bits and the corresponding "owner" and "group" are meaningless
on Coda.

The rights on Coda are managed via ACLs and there is no notion of
"ownership", neither for user nor for group. Note that "ownership" is
an artificial concept invented to be able to tag a file with separate access
rights for exactly one chosen account and exactly one chosen group.
It is thus no more than implementation of a very limited case of ACLs.

There have been discussions about what "ownership" and bits Coda might present
to the unix-centric programs like ls or file managers, and there is _no_
correct way. *nix mode bits based on "ownership" connected to a certain
(local to the host) user or group number can not describe rights on
a global file system, they are worthless in such context.

So my advice is - forget about mode bits and ownerships. Use "cfs la" instead.

Coda (unfortunately?) implements a "feature" that the "user bits"
are used by the Coda client as a hint whether to allow writing/reading
on a per file basis (in contrast to ACLs which are enforced on servers,
per directory). Such usage of the mode bits is handy when you know exactly
what it means, otherwise confusing - it has nothing to do with either
Unix semantics or ACLs.
Please do not use this feature so that it could be discontinued :)

Hope this helps,
Received on 2007-02-26 15:14:17