Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:50180 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750978Ab3I0BMq (ORCPT ); Thu, 26 Sep 2013 21:12:46 -0400 Date: Thu, 26 Sep 2013 21:12:46 -0400 From: "J. Bruce Fields" To: Jongman Heo Cc: "linux-nfs@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: Re: Re: Regression caused by commit 4bdc33ed ("NFSDv4.2: Add NFS v4.2 support to the NFS server") Message-ID: <20130927011246.GA10245@fieldses.org> References: <26120922.5161380239877162.JavaMail.weblogic@epml04> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <26120922.5161380239877162.JavaMail.weblogic@epml04> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, Sep 26, 2013 at 11:57:57PM +0000, Jongman Heo wrote: > >------- Original Message ------- > >Sender : J. Bruce Fields > >This is pretty weird--it's not at all obvious how that patch would > >affect this. > > > >You're absolutely positive that the *only* thing you're changing on the > >server between the "good" and "bad" cases is that one kernel patch? > >You're not changing anything in userspace? > > > > Yes, pretty sure. > > >What does "cat /proc/fs/nfsd/versions" report in the good and bad cases? > > > >(BTW, out of curiosity: what kind of client is this that only supports > >NFSv2 and NFSv3? Even for an embedded system that's a bit surprising.) > > > >--b. > > > > Here are /proc/fs/nfsd/versions information for good and bad cases ; > > good (commit 4bdc33ed reverted) > > # cat /proc/fs/nfsd/versions > +2 +3 +4 +4.1 > > > bad (current linus git) > > # cat /proc/fs/nfsd/versions > -2 +3 +4 +4.1 -4.2 > > > I don't know why the commit 4bdc33ed makes this difference ( from +2 to -2 ). > > My NFS server just uses Fedora 19 + latest kernel (which is not a rare setup...), The thing is, nfs-utils *did* make exactly this change with commit 6b4e4965a6b82e8d49cea1c0316b951ba4e9e83e "rpc.nfsd: No longer advertise NFS v2 support." in 1.2.9-rc4 which entered f19 recently. And that kernel commit doesn't look related. So I strongly suspect that you got the nfs-utils update (or rebooted after the update) at the same time as bisecting, and that confused the bisect results. > so I think some people can verify if this version information change happens w/ and w/o the commit revert. > > Don't know the detail of NFS protocol, but our NFS client seems not to try with v3 and v4 in case v2 fails... > Is this an unexpected (buggy) behavior of my old embedded box (NFS client of kernel 2.6.35), or expected one from the NFS protocol? Digging into a historical git repo just for fun.... It looks like NFSv3 support was added in 2.3.99pre4-3, probably in 2000? (The date on that commit is 2007, so obviously this repo I have is very confused. Maybe I should go find if there's a better one someplace.) So anyway it's either configured out of the kernel or the mount commandline's asking for v2, or I don't know what.... --b.