RFC: evolution of file management

[Eric Pouech]

Keith Matthews wrote:
> On Tue, 19 Aug 2003 23:48:53 +0200
> Ferenc Wagner <wferi at afavant.elte.hu> wrote:
> 
> 
>>Do we need attributes like hidden, system, etc?
>>                                                Feri.
>>
> 
> 
> More to the point we need attributes to allow support of NT ACLs.  I've
> been looking at the problem and progressing only very slowly, some of
> the problems are technical, others are nothing to do with Wine at all.
> 
> At the level we are dealing with here the essential problems (for those
> who have not examined the issues) are :-
> 
> 	Not all supported O/S s offer ACLs.
> 
> 	Those that do support POSIX ACLs which do not map exactly to NT ACLs
> 
> 	Even in Systems which do support POSIX ACLs there is no guarantee that
> 	all disc filesystems at any one host will offer it, Of the Linux
> 	filesystem types only XFS supports ACLs out of the box. Work is in
> 	progress for ReiserFS and due to start for JFS. There is a patch for
> 	ext2/3. One map currently favoured is to use ext2/3/Reiser for the root
> 	filesystem and XFS for (some of) the rest).
> 
> All of the systems that do support ACLs use Extended Attributes to store
> them. I am still looking at limitations on number of EAs, but there is a
> possibility that an extreme case on NT may not be supported on Linux.
> 
> Since I've not yet got round to looking at TrustedBSD there's
> potentially another can of worms there.
> 
> My conclusion is that we do (regrettably) need a VFS layer to harmonise
> handling of all this lot and respond correctly when wine-ver is 9X.
> 
> 
I think Wine's goal is to provide this kind of feature of top of what 
the underlying OS provides (this is also the case for DOS HIDDEN and 
SYSTEM attributes => there are not available in standard Posix FS, so 
are managed by wine(*)). So IMO, file (protected by ACL) access should 
be provided by the underlying OS.
ACL manipulation (from windows to posix - even if 1003.1e hasn't been 
voted by POSIX) should be added (I'm not sure we have a 1:1 mapping anyway)
however, I don't understand your remark about the winver 9x... IMO, if 
the Linux user mounts a NT partition with ACL (and has the proper 
privileges) it should run Wine on this partition rather transparently 
(except for ACL manipulation function)
it's not my goal to support:
- real FS mounting in wine => this is the job of the OS, not wine's
- a real VFS (as Linux does)
- the (V)FS I'm talking about is more related to adaptation (as you 
mention), but I'm not sure I got you right

A+

(*) except files starting with a . which get the HIDDEN attribute
-- 
Eric Pouech