Re: [PATCH 4/4] fs: take the ACL checks to common code

[Christoph Hellwig <hch@lst.de>]

On Sat, Jul 23, 2011 at 08:56:12AM -0700, Linus Torvalds wrote:
> On Sat, Jul 23, 2011 at 8:37 AM, Christoph Hellwig <hch@lst.de> wrote:
> >
> > Replace the ->check_acl method with a ->get_acl method that simply reads an
> > ACL from disk after having a cache miss. ?This means we can replace the ACL
> > checking boilerplate code with a single implementation in namei.c.
> 
> Hmm. If we just had a rule for locking (i_mutex?), we could make the
> cache update be in namei.c too..

Yes, and if we add a ->set_acl we can take most of the existing boilerplate
code completely into posix_acl.c.  I'll see if I can do something like that
for v3.2.

> Things that want to use timeouts etc to make for more complicated
> permissions rules than the straightforward acl cache have to use
> ->permission anyway, so it would make sense to make the ->get_acl
> method as trivial as possible for filesystems.

At this point no one does that anyway, the only real complications
are the cluster filesystems having remote cache invalidations.