From: Chuck Lever Subject: Re: [NLM] 2.6.27.14 breakage when grace period expires Date: Thu, 12 Feb 2009 15:43:09 -0500 Message-ID: <2171ACCA-5CF5-425D-B7A4-CFB17DA61F75@oracle.com> References: <20090211112318.GA29133@janus> <20090211203555.GC27686@fieldses.org> <20090211203703.GA9662@janus> <20090211203948.GD27686@fieldses.org> <20090212142830.GA28107@janus> <1234451789.7190.38.camel@heimdal.trondhjem.org> <20090212153634.GB28107@janus> <1234462647.7190.53.camel@heimdal.trondhjem.org> <20090212182943.GA1945@janus> <1234465837.7190.62.camel@heimdal.trondhjem.org> <03CEE6BB-D39D-47A5-BB6C-2FB3E206142F@oracle.com> <1234467795.7190.70.camel@heimdal.trondhjem.org> <1234470457.7190.106.camel@heimdal.trondhjem.org> Mime-Version: 1.0 (Apple Message framework v930.3) Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Cc: Frank van Maarseveen , "J. Bruce Fields" , Linux NFS mailing list To: Trond Myklebust Return-path: Received: from rcsinet13.oracle.com ([148.87.113.125]:36465 "EHLO rgminet13.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757647AbZBLUn2 (ORCPT ); Thu, 12 Feb 2009 15:43:28 -0500 In-Reply-To: <1234470457.7190.106.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Feb 12, 2009, at 3:27 PM, Trond Myklebust wrote: > On Thu, 2009-02-12 at 15:11 -0500, Chuck Lever wrote: >> On Feb 12, 2009, at 2:43 PM, Trond Myklebust wrote: >>> On Thu, 2009-02-12 at 14:35 -0500, Chuck Lever wrote: >>>> I wasn't sure exactly where the compared addresses came from. I >>>> had >>>> assumed that they all came through the listener, so we wouldn't >>>> need >>>> this kind of translation. It shouldn't be difficult to map >>>> addresses >>>> passed in via nlmclnt_init() to AF_INET6. >>>> >>>> But this is the kind of thing that makes "falling back" to an >>>> AF_INET >>>> listener a little challenging. We will have to record what flavor >>>> the >>>> listener is and do a translation depending on what listener family >>>> was >>>> actually created. >>> >>> Why? Should we care whether we're receiving IPv4 addresses or IPv6 >>> v4-mapped addresses? They're the same thing... >> >> The problem is the listener family is now decided at run-time. If an >> AF_INET6 listener can't be created, an AF_INET listener is created >> instead, even if CONFIG_IPV6 || CONFIG_IPV6_MODULE is enabled. If an >> AF_INET listener is created, we get only IPv4 addresses in svc_rqst- >>> rq_addr. > > You're missing my point. Why should we care if it's one or the > other? In > the NFSv4 case, we v4map all IPv4 addresses _unconditionally_ if it > turns out that CONFIG_IPV6 is enabled. > > IOW: we always compare IPv6 addresses. The reason we might care in this case is nlm_cmp_addr() is executed more frequently than nfs_sockaddr_match_ipaddr(). Mapping the server address in nlmclnt_init() means we translate the server address once and are done with it. We never have to map incoming AF_INET addresses in NLM requests, and we don't have the extra conditionals every time we go through nlm_cmp_addr(). This keeps nlm_cmp_addr() as simple as it can be: it compares only two AF_INET addresses or two AF_INET6 addresses. -- Chuck Lever chuck[dot]lever[at]oracle[dot]com