Re: [PATCH] backout the xattr override access checks flag

[Christoph Hellwig <hch@infradead.org>]

On Fri, Feb 21, 2003 at 11:20:25AM +0100, Andreas Gruenbacher wrote:
> > (not that such code even exists yet).
> 
> There is an HSM project for which this feature has been added. I think they 
> are using a loadable module.

URL?

> 
> > Something even better would probably be to move out the xattr access checks
> > to common code.
> 
> There are two problems with that, so this doesn't seem any better to me, 
> either:
> 
> (a) We would have to decode attribute names twice, once for checking 
> permissions, and a second time for determining how to store them.

Doing it in the VFS would probably mean a rather large interface change
so it should be decoded only once.  I.e. moving your current ext2/ext3-specific
handler abstraction to the VFS instead.

> (b) Different file systems may implement different features with different, 
> file system specific limitations. The VFS layer tests would have to accept 
> all potentially useful things. The file system would have to re-check.

What types of EAs do we have?

(1) user attributes - the only access checks needed are the normal DAC ones
(2) system/trusted - only privilegued access

I think that's doable.