[PATCH][WIP] Make vfs_acl_xattr use hash of the posix ACL

[Jeremy Allison]

On Tue, Oct 09, 2012 at 10:58:17PM +1100, Andrew Bartlett wrote:
> This patch (still a work in progress, as I know it fails some tests) is
> what I've been talking about for months, and which I got VFS changes in
> (almost - one small change in this patch) into 4.0.0rc1.
> 
> The idea is simple, have the ACL modules (the posix ACL modules in
> particular) provide a blob form of the ACL, and then hash that, rather
> than an NT ACL that might change if our ACL mapping code changes. 
> 
> So far I've made it simply fall back in the NFSv4 case, but we can
> define these in IDL as well if we want to do the same there. 
> 
> The idea is to insulate these on-disk values from any required change we
> have to make. 
> 
> I'm proposing these changes (once finished) for master, and will son
> have some more tests for this code.
> 
> Any thoughts or comments most appreciated.

One more thing, this needs to be split up into micro-changes, as
this will make it much easier to review (for example adding the
new hash type IDL and struct should be a separate change, etc.).

Don't worry too much about breaking the build between changes
(although it's better not to if you can avoid it), what is more
important is breaking the changes up into small chunks that are
easier to digest and understand !

Hope you don't think I'm being too negative, I actually like
what you're trying to do here, I just want to make sure it's
an easy, logical change-set to work through for anyone reading
the changes.

Cheers,

	Jeremy.