From mboxrd@z Thu Jan 1 00:00:00 1970 From: Trond Myklebust Subject: Re: [PATCH 4/5] NFS: remove RPC PipeFS mount point reference from blocklayout routines Date: Tue, 29 Nov 2011 10:18:26 -0500 Message-ID: <1322579906.3619.1.camel@lade.trondhjem.org> References: <20111129090754.20730.64567.stgit@localhost6.localdomain6> <20111129091037.20730.59391.stgit@localhost6.localdomain6> <4ED4CDCE.9080804@parallels.com> <2E1EB2CF9ED1CB4AA966F0EB76EAB4430C3CBC23@SACMVEXC2-PRD.hq.netapp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE 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 To: Peng Tao Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tue, 2011-11-29 at 23:10 +0800, Peng Tao wrote:=20 > 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.c= om; > >> neilb@suse.de; netdev@vger.kernel.org; linux-kernel@vger.kernel.or= g; > >> jbottomley@parallels.com; bfields@fieldses.org; davem@davemloft.ne= t; > >> devel@openvz.org > >> Subject: RE: [PATCH 4/5] NFS: remove RPC PipeFS mount point refere= nce > >> 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 refe= rence > >> > from blocklayout routines > >> > > >> > 29.11.2011 16:00, tao.peng@emc.com =D0=BF=D0=B8=D1=88=D0=B5=D1=82= : > >> > >> -----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@sus= e.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 refer= ence > >> > >> from blocklayout routines > >> > >> > >> > >> This is a cleanup patch. We don't need this reference anymore= , > >> > >> because blocklayout pipes dentries now creates and destroys i= n > >> > >> per-net operations and on PipeFS mount/umount notification. > >> > >> Note that nfs4blocklayout_register_net() now returns 0 instea= d of > >> > >> -ENOENT in case of PipeFS superblock absence. This is ok, bec= ause > >> > >> blocklayout pipe dentry will be created on PipeFS mount event= =2E > >> > > When is the "pipefs mount event" going to happen? When inserti= ng > >> > > kernel modules or when user issues > >> > mount command? > >> > > > >> > > >> > When user issues mount command. > >> > Kernel mounts of PipeFS has been removed with all these patch se= ts > >> > 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 pi= pe file > >> when started. > > > > Why on earth is blkmapd doing this instead of listening for file cr= eation 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 delete= d > 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... Trond --=20 Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com