Re: [PATCH 0/6 v7] overlay filesystem - request for inclusion

[Al Viro <viro@ZenIV.linux.org.uk>]

On Tue, Mar 22, 2011 at 10:36:09AM -0700, Linus Torvalds wrote:
> On Tue, Mar 22, 2011 at 8:26 AM, Miklos Szeredi <miklos@szeredi.hu> wrote:
> > Here's an updated version of the overlay filesystem. ?I'd like to
> > propose it for inclusion into mainline.
> 
> So on the whole it looked pretty small and simple. And most of the VFS
> level changes looked fine and I just reacted to the odd calling
> convention for open (I really think you should aim for ->open to have
> the basically same arguments as you made __dentry_open have: 'struct
> path', 'struct filp' and 'struct cred').
> 
> But I'd want Al's ack on the series. And also hear who uses it and how
> it's been tested?

To be honest, I *really* don't like to touch that before ->atomic_open()
is finished.  We are nearly there (the only remaining prereq is to sort out
revalidate vs. mountpoint crossing issues), so with any luck the neighborhood
of open() will be finished in for-next circa -rc3 or so.

As for the rest of it... I'll need to review that in details, but the first
impression from that code is that I don't like the way copyup is done.
Locking analysis would be really nice; AFAICS, it violates locking order
when called from e.g. ->setattr() and its protection against renames is
nowhere near enough.  I might be missing something subtle, but...