From: Benny Halevy Subject: Re: [PATCH] nfsd: use nfs client rpc callback program Date: Wed, 17 Sep 2008 18:34:06 -0500 Message-ID: <48D193EE.2020805@panasas.com> References: <48D15DF0.4000406@panasas.com> <20080917231018.GA5723@fieldses.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: Olga Kornievskaia , linux-nfs@vger.kernel.org, pnfs mailing list , Fred Isaman To: "J. Bruce Fields" Return-path: Received: from gw-ca.panasas.com ([66.104.249.162]:19055 "EHLO laguna.int.panasas.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751707AbYIQXdk (ORCPT ); Wed, 17 Sep 2008 19:33:40 -0400 In-Reply-To: <20080917231018.GA5723@fieldses.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Sep. 17, 2008, 18:10 -0500, "J. Bruce Fields" wrote: > On Wed, Sep 17, 2008 at 02:43:44PM -0500, Benny Halevy wrote: >> From: Benny Halevy >> >> since commit ff7d9756b501744540be65e172d27ee321d86103 >> "nfsd: use static memory for callback program and stats" >> do_probe_callback uses a static callback program >> (NFS4_CALLBACK) rather than the one set in clp->cl_callback.cb_prog >> as passed in by the client in setclientid (4.0) >> or create_session (4.1). > > Ugh, yes, sorry about that. (I wonder why pynfs testing didn't catch > this? Oh, I guess it's because NFS4_CALLBACK is the program number our > client always gives us.) Well, Fred (thanks!) added a test today which uses a non-default callback program and he sees a corresponding callback coming back. (Note that this test is not absolutely generic as the server is not required to probe the callback immediately, or at all, after setclientid or create_session.) > >> @@ -371,6 +356,8 @@ static int do_probe_callback(void *data) >> .to_maxval = (NFSD_LEASE_TIME/2) * HZ, >> .to_exponential = 1, >> }; >> + static struct rpc_stat cb_stats; >> + struct rpc_program cb_program; >> struct rpc_create_args args = { >> .protocol = IPPROTO_TCP, >> .address = (struct sockaddr *)&addr, >> @@ -394,6 +381,20 @@ static int do_probe_callback(void *data) >> addr.sin_port = htons(cb->cb_port); >> addr.sin_addr.s_addr = htonl(cb->cb_addr); >> >> + /* Initialize rpc_program */ >> + memset(&cb_program, 0, sizeof(cb_program)); >> + cb_program.name = "nfs4_cb"; >> + cb_program.number = clp->cl_callback.cb_prog; >> + cb_program.nrvers = ARRAY_SIZE(nfs_cb_version); >> + cb_program.version = nfs_cb_version; >> + cb_program.stats = &cb_stats; >> + memset(&cb_stats, 0, sizeof(cb_stats)); >> + cb_stats.program = &cb_program; > > You don't want a pointer to data on the stack here, do you? Hmm, you're right... I went back and forth whether this should be allocated statically, dynamically, or on the stack. I was mislead by the fact we're doing a sync rpc call, but indeed this needs to live until the nfs client is destroyed. I'm trying to fully understand what Olga saw before coming up with a new proposal... maybe putting the cb_program back into struct nfs4_callback and just make cb_stats static would provide a solution of the problem Olga witnessed and keep everybody happy. Benny > > --b.