Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx2.netapp.com ([216.240.18.37]:26386 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755955Ab1K2Qkg convert rfc822-to-8bit (ORCPT ); Tue, 29 Nov 2011 11:40:36 -0500 Message-ID: <1322584830.4174.16.camel@lade.trondhjem.org> Subject: Re: [PATCH 4/5] NFS: remove RPC PipeFS mount point reference from blocklayout routines From: Trond Myklebust To: Peng Tao Cc: tao.peng@emc.com, skinsbursky@parallels.com, linux-nfs@vger.kernel.org, xemul@parallels.com, neilb@suse.de, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jbottomley@parallels.com, bfields@fieldses.org, davem@davemloft.net, devel@openvz.org Date: Tue, 29 Nov 2011 11:40:30 -0500 In-Reply-To: References: <20111129090754.20730.64567.stgit@localhost6.localdomain6> <20111129091037.20730.59391.stgit@localhost6.localdomain6> <4ED4CDCE.9080804@parallels.com> <2E1EB2CF9ED1CB4AA966F0EB76EAB4430C3CBC23@SACMVEXC2-PRD.hq.netapp.com> <1322579906.3619.1.camel@lade.trondhjem.org> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, 2011-11-29 at 23:30 +0800, Peng Tao wrote: > On Tue, Nov 29, 2011 at 11:18 PM, Trond Myklebust > wrote: > > On Tue, 2011-11-29 at 23:10 +0800, Peng Tao wrote: > >> On Tue, Nov 29, 2011 at 9:35 PM, Myklebust, Trond > >> wrote: > >> >> -----Original Message----- > >> >> From: tao.peng@emc.com [mailto:tao.peng@emc.com] > >> >> Sent: Tuesday, November 29, 2011 7:40 AM > >> >> To: skinsbursky@parallels.com > >> >> Cc: Myklebust, Trond; linux-nfs@vger.kernel.org; xemul@parallels.com; > >> >> neilb@suse.de; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; > >> >> jbottomley@parallels.com; bfields@fieldses.org; davem@davemloft.net; > >> >> devel@openvz.org > >> >> Subject: RE: [PATCH 4/5] NFS: remove RPC PipeFS mount point reference > >> >> from blocklayout routines > >> >> > >> >> > -----Original Message----- > >> >> > From: Stanislav Kinsbursky [mailto:skinsbursky@parallels.com] > >> >> > Sent: Tuesday, November 29, 2011 8:19 PM > >> >> > To: Peng, Tao > >> >> > Cc: Trond.Myklebust@netapp.com; linux-nfs@vger.kernel.org; Pavel > >> >> > Emelianov; neilb@suse.de; netdev@vger.kernel.org; > >> >> > linux-kernel@vger.kernel.org; James Bottomley; bfields@fieldses.org; > >> >> > davem@davemloft.net; devel@openvz.org > >> >> > Subject: Re: [PATCH 4/5] NFS: remove RPC PipeFS mount point reference > >> >> > from blocklayout routines > >> >> > > >> >> > 29.11.2011 16:00, tao.peng@emc.com пишет: > >> >> > >> -----Original Message----- > >> >> > >> From: linux-nfs-owner@vger.kernel.org > >> >> > >> [mailto:linux-nfs-owner@vger.kernel.org] On Behalf Of > >> >> > Stanislav > >> >> > >> Kinsbursky > >> >> > >> Sent: Tuesday, November 29, 2011 6:11 PM > >> >> > >> To: Trond.Myklebust@netapp.com > >> >> > >> Cc: linux-nfs@vger.kernel.org; xemul@parallels.com; neilb@suse.de; > >> >> > >> netdev@vger.kernel.org; linux- kernel@vger.kernel.org; > >> >> > >> jbottomley@parallels.com; bfields@fieldses.org; > >> >> > >> davem@davemloft.net; devel@openvz.org > >> >> > >> Subject: [PATCH 4/5] NFS: remove RPC PipeFS mount point reference > >> >> > >> from blocklayout routines > >> >> > >> > >> >> > >> This is a cleanup patch. We don't need this reference anymore, > >> >> > >> because blocklayout pipes dentries now creates and destroys in > >> >> > >> per-net operations and on PipeFS mount/umount notification. > >> >> > >> Note that nfs4blocklayout_register_net() now returns 0 instead of > >> >> > >> -ENOENT in case of PipeFS superblock absence. This is ok, because > >> >> > >> blocklayout pipe dentry will be created on PipeFS mount event. > >> >> > > When is the "pipefs mount event" going to happen? When inserting > >> >> > > kernel modules or when user issues > >> >> > mount command? > >> >> > > > >> >> > > >> >> > When user issues mount command. > >> >> > Kernel mounts of PipeFS has been removed with all these patch sets > >> >> > I've sent already. > >> >> Then it is going to break blocklayout user space program blkmapd, which is > >> >> stared before mounting any file system and it tries to open the pipe file > >> >> when started. > >> > > >> > Why on earth is blkmapd doing this instead of listening for file creation notifications like the other rpc_pipefs daemons do? > >> Not sure how the original implementer chose this but I think it is > >> likely because we do not expect the pipe file to be created or deleted > >> dynamically. > > > > Unless blkmapd can pin the sunrpc module (which it shouldn't be able to) > > then that assumption would be wrong. Please look into fixing blkmapd... > Sorry, I don't quite get it. Do you mean sunrpc module may be removed > while nfs/blocklayout modules are still in use? Please explain it a > bit. Thanks. I mean that I'm perfectly entitled to do 'modprobe -r blocklayoutdriver' and when I do that, then I expect blkmapd to close the rpc pipe and wait for a new one to be created just like rpc.idmapd and rpc.gssd do when I remove the nfs and sunrpc modules. -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com