From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754720Ab2IHOdQ (ORCPT ); Sat, 8 Sep 2012 10:33:16 -0400 Received: from mx2.netapp.com ([216.240.18.37]:63349 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754117Ab2IHOdN (ORCPT ); Sat, 8 Sep 2012 10:33:13 -0400 X-IronPort-AV: E=Sophos;i="4.80,391,1344236400"; d="scan'208";a="687249983" From: "Myklebust, Trond" To: Stanislav Kinsbursky CC: Jeff Layton , "bfields@fieldses.org" , "linux-nfs@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "devel@openvz.org" Subject: Re: [PATCH v2] SUNRPC: check current nsproxy before set of node name on client creation Thread-Topic: [PATCH v2] SUNRPC: check current nsproxy before set of node name on client creation Thread-Index: AQHNeUylwnVjh2tbW02Id+IcJKD75ZeAFAKAgAB9EYCAAI9kAA== Date: Sat, 8 Sep 2012 14:33:09 +0000 Message-ID: <4FA345DA4F4AE44899BD2B03EEEC2FA908F914D4@SACEXCMBX04-PRD.hq.netapp.com> References: <20120813113731.9629.31906.stgit@localhost.localdomain> <20120813081054.0ee39037@corrin.poochiereds.net> <4FA345DA4F4AE44899BD2B03EEEC2FA908F90888@SACEXCMBX04-PRD.hq.netapp.com> <504ADED9.2020607@parallels.com> In-Reply-To: <504ADED9.2020607@parallels.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.104.60.116] Content-Type: text/plain; charset="utf-8" Content-ID: <5D2A4604819E8E4EBF59B9360EA0265C@tahoe.netapp.com> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id q88EYFQo011512 On Sat, 2012-09-08 at 08:59 +0300, Stanislav Kinsbursky wrote: > 08.09.2012 01:32, Myklebust, Trond пишет: > > On Mon, 2012-08-13 at 08:10 -0400, Jeff Layton wrote: > >> On Mon, 13 Aug 2012 15:37:31 +0400 > >> Stanislav Kinsbursky wrote: > >> > >>> v2: > >>> 1) rpc_clnt_set_nodename() prototype updated. > >>> 2) fixed errors in comment. > >>> > >>> When child reaper exits, it can destroy mount namespace it belongs to, and if > >>> there are NFS mounts inside, then it will try to umount them. But in this > >>> point current->nsproxy is set to NULL and all namespaces will be destroyed one > >>> by one. I.e. we can't dereference current->nsproxy to obtain uts namespace. > >>> > >>> Signed-off-by: Stanislav Kinsbursky > >>> --- > >>> net/sunrpc/clnt.c | 16 +++++++++++++--- > >>> 1 files changed, 13 insertions(+), 3 deletions(-) > >>> > >>> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c > >>> index 9a9676e..8fbcbc8 100644 > >>> --- a/net/sunrpc/clnt.c > >>> +++ b/net/sunrpc/clnt.c > >>> @@ -277,8 +277,18 @@ void rpc_clients_notifier_unregister(void) > >>> return rpc_pipefs_notifier_unregister(&rpc_clients_block); > >>> } > >>> > >>> -static void rpc_clnt_set_nodename(struct rpc_clnt *clnt, const char *nodename) > >>> +static void rpc_clnt_set_nodename(struct rpc_clnt *clnt) > >>> { > >>> + const char *nodename; > >>> + > >>> + /* > >>> + * We have to protect against dying child reaper, which has released > >>> + * its nsproxy already and is trying to destroy mount namespace. > >>> + */ > >>> + if (current->nsproxy == NULL) > >>> + return; > >>> + > >>> + nodename = utsname()->nodename; > >>> clnt->cl_nodelen = strlen(nodename); > >>> if (clnt->cl_nodelen > UNX_MAXNODENAME) > >>> clnt->cl_nodelen = UNX_MAXNODENAME; > >>> @@ -365,7 +375,7 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru > >>> } > >>> > >>> /* save the nodename */ > >>> - rpc_clnt_set_nodename(clnt, utsname()->nodename); > >>> + rpc_clnt_set_nodename(clnt); > >>> rpc_register_client(clnt); > >>> return clnt; > >>> > >>> @@ -524,7 +534,7 @@ rpc_clone_client(struct rpc_clnt *clnt) > >>> err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name); > >>> if (err != 0) > >>> goto out_no_path; > >>> - rpc_clnt_set_nodename(new, utsname()->nodename); > >>> + rpc_clnt_set_nodename(new); > >>> if (new->cl_auth) > >>> atomic_inc(&new->cl_auth->au_count); > >>> atomic_inc(&clnt->cl_count); > >>> > >>> -- > >>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > >>> the body of a message to majordomo@vger.kernel.org > >>> More majordomo info at http://vger.kernel.org/majordomo-info.html > >> Acked-by: Jeff Layton > > OK, colour me confused (again). > > What color? > > > Why should a umount trigger an > > rpc_create() or rpc_clone_client()? > > It calls nsm_create(). > Here is the trace (https://bugzilla.redhat.com/show_bug.cgi?id=830862, > comment 68): Right, but if we're using NFSv3 lock monitoring, we know in advance that we're going to need an nsm call to localhost. Why can't we just cache the one that we used to start lock monitoring in the first place? -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I