Re: reiser4 plugins

From: Kyle Moffett
Date: Tue Jun 28 2005 - 15:11:49 EST


On Jun 28, 2005, at 13:51:04, Hubert Chan wrote:
On Tue, 28 Jun 2005 02:01:12 -0400, Kyle Moffett <mrmacman_g4@xxxxxxx> 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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