Oops in NFSv4 server in 2.6.23.17

[J. Bruce Fields]

On Mon, Mar 17, 2008 at 10:19:20AM +1100, Neil Brown wrote:
> On Friday March 14, bfields at fieldses.org wrote:
> > On Fri, Mar 14, 2008 at 04:05:10PM -0400, bfields wrote:
> > > I find that a little contorted.  So I'll go ahead and submit this small
> > > patch to 2.6.25 and stable now (I have since managed to reproduce what I
> > > believe is your bug, though my symptoms were a little different), and
> > > then submit to 2.6.26 some cleanup which makes this more understandable,
> > 
> > Here's an attempt.  We could break up fh_verify even more, though.--b.
> 
> Looks like a good attempt.
> 
> My only suggestion would be to put a comment at the top of
> nfsd_set_fh_dentry explaining what it does and who calls it.

OK!  I'm planning to just add:

+/*
+ * Use the given filehandle to look up the corresponding export and
+ * dentry.  On success, the results are used to set fh_export and
+ * fh_dentry.
+ */
 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 {
 	struct knfsd_fh	*fh = &fhp->fh_handle;

(Nothing about "who calls it", but it's static and its only caller is
fh_verify, so that seemed uninteresting.)  Anything else you were
looking for?

> 
> It's long past time that code had some spring cleaning !!

If I had a little more time I think it might be clearer to make this:

	fhp->fh_export = nfsd_fh_get_export(rqstp, &fhp->fh_handle);
	if (IS_ERR(fhp->fh_export))
		return ERR_PTR(fhp->fh_export);
	error = nfsd_setuser_and_check_port(rqstp, exp);
	if (error)
		goto out;
	fhp->fh_export = nfsd_fh_get_dentry(rqstp, &fhp->fh_handle);
	if (IS_ERR(...))

etc., though that's probably not quite right.

--b.