From: "Myklebust, Trond" <Trond.Myklebust@netapp.com>
To: "J. Bruce Fields" <bfields@fieldses.org>
CC: Simo Sorce <simo@redhat.com>,
        Linux NFS Mailing list <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH 2/2] Document new -z/-Z options
Date: Wed, 3 Apr 2013 14:35:48 +0000
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References: <515B2F8D.3030302@RedHat.com>
	 <1364931149-18484-3-git-send-email-simo@redhat.com>
	 <20130403142003.GC13951@fieldses.org>
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On Wed, 2013-04-03 at 10:20 -0400, J. Bruce Fields wrote:
> On Tue, Apr 02, 2013 at 03:32:29PM -0400, Simo Sorce wrote:
> > Options are not in alphabetical order but -z/-Z clearly always come last.
> > 
> > Signed-off-by: Simo Sorce <simo@redhat.com>
> > ---
> >  utils/gssd/gssd.man |   13 ++++++++++++-
> >  1 files changed, 12 insertions(+), 1 deletions(-)
> > 
> > diff --git a/utils/gssd/gssd.man b/utils/gssd/gssd.man
> > index 79d9bf91ac6b976c57d167e60d07f828a3ff5b1f..7918c2a0ff76c3918449cf3e1420f0a289929ac1 100644
> > --- a/utils/gssd/gssd.man
> > +++ b/utils/gssd/gssd.man
> > @@ -8,7 +8,7 @@
> >  rpc.gssd \- RPCSEC_GSS daemon
> >  .SH SYNOPSIS
> >  .B rpc.gssd
> > -.RB [ \-fMnlvr ]
> > +.RB [ \-fMnlvrzZ ]
> >  .RB [ \-k
> >  .IR keytab ]
> >  .RB [ \-p
> > @@ -266,6 +266,17 @@ new kernel contexts to be negotiated after
> >  seconds, which allows changing Kerberos tickets and identities frequently.
> >  The default is no explicit timeout, which means the kernel context will live
> >  the lifetime of the Kerberos service ticket used in its creation.
> > +.TP
> > +.B -z
> > +This option tries to avoid DNS Reverse (PTR) lookups for determining the 
> > +server name to pass to GSSAPI if the name passed at mount point is not an IP 
> > +address. Currently off by default for compatibility reasons.
> > +.TP
> > +.B -Z
> > +This is the inverse of 
> > +.B -z
> > +and forces the use of DNS Reverse resolution of the server's IP address to
> > +retrieve the server name to use in GSAPI authentication.
> 
> By the way I think with the "new" upcall, gssd ignores whatever it got
> out of the info file if the "target=" parameter is provided in the
> upcall.

Correct.

> (But looking at the code I think that's only used in the nfsv4.0
> callback case, and isn't worth mentioning here.)

Wrong. It is also used for NFSv4 and NFSv4.1 state management.
IOW: SETCLIENTID/RENEW and for NFSv4.1 EXCHANGE_ID/SEQUENCE; anything
that uses clp->cl_machine_cred.

-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com