Re: [nfsv4] open(O_CREAT) returns EEXISTS on symbolic link created on another system until stat()ed

[Dr James Bruce Fields <bfields@fieldses.org>]

On Thu, Mar 29, 2012 at 08:16:05PM +0000, Myklebust, Trond wrote:
> On Thu, 2012-03-29 at 15:31 -0400, Dr James Bruce Fields wrote:
> > On Thu, Mar 29, 2012 at 12:07:17PM -0600, Orion Poplawski wrote:
> > > On 03/29/2012 11:40 AM, Myklebust, Trond wrote:
> > > >>Going back to v4 on EL5.8 server: nfsv4el.log, nfsv4f18.log
> > > >>
> > > >>Both get NFS4ERR_EXIST in this case.
> > > >
> > > >Which is an obvious server bug: it should be sending NFS4ERR_SYMLINK in
> > > >reply to that OPEN.
> > > >
> > > >Bruce?
> > > >
> > > 
> > > I can reproduce with a 3.4.0-0.rc0.git1.2.fc18 server as well.
> > 
> > Hm.  So how about this?  (Untested.)
> > 
> > Probably there should be a pynfs test too.
> > 
> > I'm assuming it should still be ERR_EXIST in the exclusive,
> > exclusive4_1, and guarded cases.
> > 
> > --b.
> > 
> > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> > index 7423d71..2bfcad4 100644
> > --- a/fs/nfsd/vfs.c
> > +++ b/fs/nfsd/vfs.c
> > @@ -1457,9 +1457,12 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
> >  
> >  		switch (createmode) {
> >  		case NFS3_CREATE_UNCHECKED:
> > -			if (! S_ISREG(dchild->d_inode->i_mode))
> > -				err = nfserr_exist;
> > -			else if (truncp) {
> > +			if (! S_ISREG(dchild->d_inode->i_mode)) {
> > +				if (rqstp->rq_vers == 4)
> > +					err = nfserr_symlink;
> > +				else
> > +					err = nfserr_exist;
> 
> No. This should _never_ return NFS4ERR_EXIST.

That "else" is the v3 CREATE case.  I don't see the alternative there?

> It should return
>       * NFS4ERR_ISDIR if the object is a directory
>       * NFS4ERR_SYMLINK if it is symbolic link,
>       * either NFS4ERR_WRONG_TYPE (NFSv4.1) or NFS4ERR_SYMLINK (NFSv4.0)
>         if the object is any other non-regular file.

Makes sense.

--b.

> 
> 
> > +			} else if (truncp) {
> >  				/* in nfsv4, we need to treat this case a little
> >  				 * differently.  we don't want to truncate the
> >  				 * file now; this would be wrong if the OPEN
> 
> -- 
> Trond Myklebust
> Linux NFS client maintainer
> 
> NetApp
> Trond.Myklebust@netapp.com
> www.netapp.com
>