From: "J. Bruce Fields" Subject: Re: [PATCH 1/2] nfsd: fix version-setting regression on old kernels Date: Thu, 4 Feb 2010 16:47:09 -0500 Message-ID: <20100204214709.GI8779@fieldses.org> References: <1264631166-21898-1-git-send-email-bfields@citi.umich.edu> <4B6B3E30.8090907@RedHat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-nfs@vger.kernel.org To: Steve Dickson Return-path: Received: from fieldses.org ([174.143.236.118]:43637 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756513Ab0BDVqy (ORCPT ); Thu, 4 Feb 2010 16:46:54 -0500 In-Reply-To: <4B6B3E30.8090907-AfCzQyP5zfLQT0dZR+AlfA@public.gmane.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, Feb 04, 2010 at 04:37:52PM -0500, Steve Dickson wrote: > > > On 01/27/2010 05:26 PM, J. Bruce Fields wrote: > > /proc/fs/nfsd/versions was extended to allow turning on/off minor > > versions by echoing "+4.1" or "-4.1" to /proc/fs/nsfd/versions. > > > > Unfortunately, pre-2.6.30 kernels just stop parsing at first non-digit, > > so "-4.1" is interpreted as "-4". If new nfs-utils (on old kernel) > > writes "+2", "+3", "+4", then "-4.1", result therefore is to turn off > > 4.1. > > > > Given that historical behavior, it may have been a mistake to extend the > > interface the way we did; but at this point we're probably stuck with > > it. So, just reverse the order we write versions in. > > > > Signed-off-by: J. Bruce Fields > > --- > > utils/nfsd/nfssvc.c | 10 +++++----- > > 1 files changed, 5 insertions(+), 5 deletions(-) > > > > diff --git a/utils/nfsd/nfssvc.c b/utils/nfsd/nfssvc.c > > index b8028bb..7bbbaba 100644 > > --- a/utils/nfsd/nfssvc.c > > +++ b/utils/nfsd/nfssvc.c > > @@ -238,17 +238,17 @@ nfssvc_setvers(unsigned int ctlbits, int minorvers4) > > if (fd < 0) > > return; > > > > + n = minorvers4 >= 0 ? minorvers4 : -minorvers4; > > + if (n >= NFSD_MINMINORVERS4 && n <= NFSD_MAXMINORVERS4) > > + off += snprintf(ptr+off, sizeof(buf) - off, "%c4.%d", > There needs to be a space between the %d and ". > > But more importantly what problem is the patch fixing?? I've tested this > on a 2.6.29 and 2.6.31 as well as a 2.6.33 kernel and I see no different > in how the versions are ordered. See the patch description. A test case: - boot 2.6.29 - run 'nfsd -N4.1' - try to mount v4.0. See also https://bugzilla.redhat.com/show_bug.cgi?id=512377. --b. > Note, as you probably already know, the kernel will always display > the versions in descending order... > > steved. > >