From: "J. Bruce Fields" Subject: Re: [PATCH 2/2] nfsd4: fix callback program version Date: Tue, 18 May 2010 18:48:49 -0400 Message-ID: <20100518224848.GA26911@fieldses.org> References: <1273877123-23617-1-git-send-email-bfields@citi.umich.edu> <1273877123-23617-2-git-send-email-bfields@citi.umich.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: linux-nfs@vger.kernel.org Return-path: Received: from fieldses.org ([174.143.236.118]:60889 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752432Ab0ERWst (ORCPT ); Tue, 18 May 2010 18:48:49 -0400 Received: from bfields by fieldses.org with local (Exim 4.69) (envelope-from ) id 1OEVaj-00070m-3j for linux-nfs@vger.kernel.org; Tue, 18 May 2010 18:48:49 -0400 In-Reply-To: <1273877123-23617-2-git-send-email-bfields@citi.umich.edu> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Fri, May 14, 2010 at 06:45:23PM -0400, J. Bruce Fields wrote: > The 4.1 rfc actually specifices that the callback program must have > version 4. > > As far as I can tell, this was unspecified in rfc 3530. But it looks to > me like the NFSv4 client only ever accepted version 1! > > Newer linux clients allow either 1 or 4, for either minor version. > > So, the safest approach seems to be to use version 1 for 4.0 clients, > and version 4 for 4.1 clients. OK, following further discussion on the ietf list, let's stick to version 1 for now and just add a comment. --b. commit b7299f44394336f51b526247a870d47d28f4f97c Author: J. Bruce Fields Date: Fri May 14 17:57:35 2010 -0400 nfs4: minor callback code simplification, comment Note the position in the version array doesn't have to match the actual rpc version number--to me it seems clearer to maintain the distinction. Also document choice of rpc callback version number, as discussed in e.g. http://www.ietf.org/mail-archive/web/nfsv4/current/msg07985.html and followups. Signed-off-by: J. Bruce Fields diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c index 77bc9d3..eb78e7e 100644 --- a/fs/nfsd/nfs4callback.c +++ b/fs/nfsd/nfs4callback.c @@ -424,13 +424,19 @@ static struct rpc_procinfo nfs4_cb_procedures[] = { }; static struct rpc_version nfs_cb_version4 = { +/* + * Note on the callback rpc program version number: despite language in rfc + * 5661 section 18.36.3 requiring servers to use 4 in this field, the + * official xdr descriptions for both 4.0 and 4.1 specify version 1, and + * in practice that appears to be what implementations use. The section + * 18.36.3 language is expected to be fixed in an erratum. + */ .number = 1, .nrprocs = ARRAY_SIZE(nfs4_cb_procedures), .procs = nfs4_cb_procedures }; static struct rpc_version * nfs_cb_version[] = { - NULL, &nfs_cb_version4, }; @@ -471,7 +477,7 @@ int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *cb) .timeout = &timeparms, .program = &cb_program, .prognumber = cb->cb_prog, - .version = nfs_cb_version[1]->number, + .version = 0, .authflavor = clp->cl_flavor, .flags = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET), .client_name = clp->cl_principal,