Re: [PATCH -V8 00/26] New ACL format for better NFSv4 aclinteroperability

From: J. Bruce Fields
Date: Mon Oct 24 2011 - 07:08:11 EST

On Mon, Oct 24, 2011 at 05:49:10AM -0400, Christoph Hellwig wrote:
> On Mon, Oct 24, 2011 at 05:17:16AM -0400, J. Bruce Fields wrote:
> > > How do we push these changes to Linus tree ? Andrew, Viro, any comment
> > > on how we can get this merged upstream ?
> >
> > Andrew, it sounds like you might be willing to shepherd these through?
> > Let us know what you'd need.
> It really has to through the VFS tree.

Do we have a VFS tree right now?

> And to be honest despite the repostings there's been exactly zero
> progress on getting there.

Apparently some review was missed--do you have pointers to it, if
there's anything that isn't covered below?

> Please as a first thing submit the various small cleanups indepent
> of the other changes. If you can't even those in there's no point
> in trying. Second do not repeat the mistakes of the old ACL code,
> that is don't do too much work inside the filesystems. Al, Linus
> and me spent a lot of working on pushing it into common code and
> it's not done. For any new ACL model I really want to see zero
> per-fs code except for callouts in chmod & co and actually
> setting the xattr vector to a genericly provided one. And please
> wire up all common filesystems to actually prove that point.

Sounds reasonable.

> I also really hate all the duplication - I want to see a really good
> reason why all this code needs to be duplicated. Just look at
> the mess done to check_acl and the ACL caching in the inode and
> any normal person would throw up. There is absolutely no reason
> to not implement Posix ACLs as a subset of the NFSv4 ACL (not actually
> a subset in the strict mathematical sense, but close enough).

Just to make sure I understand: you're just talking about the
implementation here--you want as much as possible to be done by routines
shared by NFSv4 and Posix ACLs--right? (You're not suggesting that e.g.
a user should be able to treat NFSv4 ACLs as if they were Posix ACLs.)

> After all this techical work (which was brought up before) has been
> done you can resubmit it. And that point you'd better have very
> good and very lengthy rationale for why adding an utterly stupid
> ACL model is supposed to be a good idea.

It's the ACL model that Samba and NFSv4 clients use, and we want to do a
better job of exporting linux filesystems to those clients.

I don't know how to make the justification much longer than that.

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