From: Chuck Lever Subject: Re: [RFC][PATCH 2/4] sunrpc: Use utsnamespaces Date: Tue, 6 Jan 2009 17:29:05 -0500 Message-ID: References: <20090106011314.534653345@us.ibm.com> <20090106011314.961946803@us.ibm.com> <20090106200229.GA17031@us.ibm.com> Mime-Version: 1.0 (Apple Message framework v930.3) Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Cc: Matt Helsley , Linux Containers , linux-nfs@vger.kernel.org, Linux Kernel Mailing List , Trond Myklebust , "J. Bruce Fields" , "Eric W. Biederman" , Linux Containers , Cedric Le Goater To: "Serge E. Hallyn" Return-path: Received: from rcsinet12.oracle.com ([148.87.113.124]:42904 "EHLO rgminet12.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756249AbZAFWbD (ORCPT ); Tue, 6 Jan 2009 17:31:03 -0500 In-Reply-To: <20090106200229.GA17031@us.ibm.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Jan 6, 2009, at Jan 6, 2009, 3:02 PM, Serge E. Hallyn wrote: > Quoting Matt Helsley (matthltc@us.ibm.com): >> We can often specify the UTS namespace to use when starting an RPC >> client. >> However sometimes no UTS namespace is available (specifically >> during system >> shutdown as the last NFS mount in a container is unmounted) so fall >> back to the initial UTS namespace. > > So what happens if we take this patch and do nothing else? I thought the point of this was to prevent incorrect container nodenames from leaking onto the network. > The only potential problem situation will be rpc requests > made on behalf of a container in which the last task has > exited, right? So let's say a container did an nfs mount > and then exits, causing an nfs umount request. > > That umount request will now be sent with the wrong nodename. > Does that actually cause problems, will the server use the > nodename to try and determine the client sending the request? > > thanks, > -serge > >> Signed-off-by: Matt Helsley >> Cc: Cedric Le Goater >> Cc: Linux Kernel Mailing List >> Cc: linux-nfs@vger.kernel.org >> Cc: Trond Myklebust >> Cc: Chuck Lever >> Cc: Eric W. Biederman >> Cc: Linux Containers >> >> --- >> net/sunrpc/clnt.c | 7 +++++-- >> 1 file changed, 5 insertions(+), 2 deletions(-) >> >> Index: linux-2.6.28/net/sunrpc/clnt.c >> =================================================================== >> --- linux-2.6.28.orig/net/sunrpc/clnt.c >> +++ linux-2.6.28/net/sunrpc/clnt.c >> @@ -128,6 +128,7 @@ static struct rpc_clnt * rpc_new_client( >> struct rpc_version *version; >> struct rpc_clnt *clnt = NULL; >> struct rpc_auth *auth; >> + struct new_utsname *uts_ns = init_utsname(); >> int err; >> size_t len; >> >> @@ -213,10 +214,12 @@ static struct rpc_clnt * rpc_new_client( >> } >> >> /* save the nodename */ >> - clnt->cl_nodelen = strlen(init_utsname()->nodename); >> + if (current->nsproxy != NULL) >> + uts_ns = utsname(); >> + clnt->cl_nodelen = strlen(uts_ns->nodename); >> if (clnt->cl_nodelen > UNX_MAXNODENAME) >> clnt->cl_nodelen = UNX_MAXNODENAME; >> - memcpy(clnt->cl_nodename, init_utsname()->nodename, clnt- >> >cl_nodelen); >> + memcpy(clnt->cl_nodename, uts_ns->nodename, clnt->cl_nodelen); >> rpc_register_client(clnt); >> return clnt; >> >> >> -- >> _______________________________________________ >> Containers mailing list >> Containers@lists.linux-foundation.org >> https://lists.linux-foundation.org/mailman/listinfo/containers -- Chuck Lever chuck[dot]lever[at]oracle[dot]com