Re: reiser4 plugins

[Kyle Moffett <mrmacman_g4@mac.com>]

On Jun 28, 2005, at 13:51:04, Hubert Chan wrote:
> On Tue, 28 Jun 2005 02:01:12 -0400, Kyle Moffett  
> <mrmacman_g4@mac.com> said:
> > I don't disagree with the thumbnail/icon/description, but things like
> > POSIX acls and extended attributes have _existing_ interfaces which
> > should be used.
>
> OK.  I agree with that.  Of course, Reiser4 can always present both
> interfaces, just like it presented two interfaces to the stat data --
> the regular interface and the metas (now '...') interface -- before
> file-as-dir got disabled by default.

Yeah, but let's get the normal interface working first and discuss what
form the alternate one should take

> > I don't deny them the right to add other interfaces later, but such
> > should be a secondary or tertiary patch, after the rest of the stuff
> > is in.  In any case, if we were to provide an interface by which one
> > could $EDITOR the POSIX ACLs, it should be done in the VFS where all
> > filesystems can share it.
>
> I don't know if VFS is the right place for it, but I agree that it  
> would
> be good to make it accessible to all filesystems.

That's somewhat of a contradiction in terms.  The whole point of the VFS
is to hold all of the things that multiple filesystems want to  
share :-D.

> > The key difference here is that Mac OS X does all of the bundle mess
> > in userspace where it belongs. :-D (I know, I use it daily)
>
> Yes.  It's handled by NSWorkspace which is approximately equivalent to
> this sort of thing being handled by GnomeVFS or the KDE  
> equivalent.  Of
> course the problem with handling it in userspace is that behaviour  
> isn't
> uniform -- applications that don't use NSWorkspace (e.g. some
> command-line utils, programs ported over from UNIX, etc.) won't  
> have the
> same behaviour.  Whether or not that is an actual problem seems to be
> debatable.  (I don't use MacOS X, but I've done some programming in
> GNUstep.)

Personally, I think that the multiple views is a good thing.  I like
being able to "cd /Applications/Games/UnrealTournament2004.app/System"
and mess with my game files, while double-clicking it in the Finder
just starts it so I can get on with owning my friends :-D.

> Another problem is that it only works with bundle files.  e.g. I can't
> add an icon to a regular txt file.  Tiger now supports xattrs,  
> which you
> could use for that functionality, but then we run into the problem  
> again
> of not being able to edit it with regular applications.

Maybe we just need better regular applications?  I think that for the
icon case, for the Samba/streams case, and for many others I'm probably
forgetting, we should try to come up with a new "data-stream" VFS API,
so that the icon data and other larger quantities can be stored in a
filesystem without much effort.  Such a layer could even be bridged
onto existing filesystems via a VFS-wrapper bind-mount:

# mount -t reiser4 /dev/hda1 /mnt1

# mount -t ext3 /dev/hda2 /mnt2

# cat $(metapath /mnt1/foo)/streams/description
Some random file

# cat $(metapath /mnt2/foo)/streams/description
cat: Unsupported operation

# mount -t none -o bind,streamify /mnt2 /mnt3

# cat $(metapath /mnt3/foo)/streams/description
Another random file

Such a wrapper interface might use the directory '...' to store files on
the underlying filesystem, but I don't think that the meta interface
itself should use those directories.

Cheers,
Kyle Moffett

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