From patchwork Fri Mar 10 00:36:39 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 9614403 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 744B8604D9 for ; Fri, 10 Mar 2017 00:38:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 67000286E6 for ; Fri, 10 Mar 2017 00:38:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5BA29286DC; Fri, 10 Mar 2017 00:38:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BE850286DC for ; Fri, 10 Mar 2017 00:38:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754629AbdCJAi3 (ORCPT ); Thu, 9 Mar 2017 19:38:29 -0500 Received: from mx2.suse.de ([195.135.220.15]:32829 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754539AbdCJAi2 (ORCPT ); Thu, 9 Mar 2017 19:38:28 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 7E586AB5D; Fri, 10 Mar 2017 00:38:21 +0000 (UTC) From: NeilBrown To: "J. Bruce Fields" Date: Fri, 10 Mar 2017 11:36:39 +1100 Subject: [PATCH 1/3] NFSD: further refinement of content of /proc/fs/nfsd/versions Cc: Trond Myklebust , linux-nfs@vger.kernel.org Message-ID: <148910619911.3032.4329058022476162122.stgit@noble> In-Reply-To: <148910618557.3032.8265198632788708076.stgit@noble> References: <148910618557.3032.8265198632788708076.stgit@noble> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Prior to e35659f1b03c ("NFSD: correctly range-check v4.x minor version when setting versions.") v4.0 could not be disabled without disabling all NFSv4 protocols. So the 'versions' file contained ±4 ±4.1 ±4.2. Writing "-4" would disable all v4 completely. Writing +4 would enabled those minor versions that are currently enabled, either by default or otherwise. After that commit, it was possible to disable v4.0 independently. To maximize backward compatibility with use cases which never disabled v4.0, the "versions" file would never contain "+4.0" - that was implied by "+4", unless explicitly negated by "-4.0". This introduced an inconsistency in that it was possible to disable all minor versions, but still have the major version advertised. e.g. "-4.0 -4.1 -4.2 +4" would result in NFSv4 support being advertised, but all attempts to use it rejected. Commit d3635ff07e8c ("nfsd: fix configuration of supported minor versions") and following removed this inconsistency. If all minor version were disabled, the major would be disabled too. If any minor was enabled, the major would be disabled. This patch also treated "+4" as equivalent to "+4.0" and "-4" as "-4.0". A consequence of this is that writing "-4" would only disable 4.0. This is a regression against the earlier behaviour, in a use case that rpc.nfsd actually uses. The command "rpc.nfsd -N 4" will write "+2 +3 -4" to the versions files. Previously, that would disable v4 completely. Now it will only disable v4.0. Also "4.0" never appears in the "versions" file when read. So if only v4.1 is available, the previous kernel would have reported "+4 -4.0 +4.1 -4.2" the current kernel reports "-4 +4.1 -4.2" which could easily confuse. This patch restores the implication that "+4" and "-4" apply more globals and do not imply "4.0". Specifically: writing "-4" will disable all 4.x minor versions. writing "+4" will enable all 4.1 minor version if none are currently enabled. rpc.nfsd will list minor versions before major versions, so rpc.nfsd -V 4.2 -N 4.1 will write "-4.1 +4.2 +2 +3 +4" so it would be a regression for "+4" to enable always all versions. reading "-4" implies that no v4.x are enabled reading "+4" implies that some v4.x are enabled, and that v4.0 is enabled unless "-4.0" is also present. All other minor versions will explicitly be listed. Signed-off-by: NeilBrown --- fs/nfsd/nfsctl.c | 43 +++++++++++++++++++++++++++++++++---------- 1 file changed, 33 insertions(+), 10 deletions(-) -- 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 diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index 73e75ac90525..8bf8f667a8cf 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -538,13 +538,21 @@ static ssize_t write_pool_threads(struct file *file, char *buf, size_t size) static ssize_t nfsd_print_version_support(char *buf, int remaining, const char *sep, - unsigned vers, unsigned minor) + unsigned vers, int minor) { - const char *format = (minor == 0) ? "%s%c%u" : "%s%c%u.%u"; + const char *format = minor < 0 ? "%s%c%u" : "%s%c%u.%u"; bool supported = !!nfsd_vers(vers, NFSD_TEST); - if (vers == 4 && !nfsd_minorversion(minor, NFSD_TEST)) + if (vers == 4 && minor >= 0 && + !nfsd_minorversion(minor, NFSD_TEST)) supported = false; + if (minor == 0 && supported) + /* + * special case for backward compatability. + * +4.0 is never reported, it is implied by + * +4, unless -4.0 is present. + */ + return 0; return snprintf(buf, remaining, format, sep, supported ? '+' : '-', vers, minor); } @@ -554,7 +562,6 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size) char *mesg = buf; char *vers, *minorp, sign; int len, num, remaining; - unsigned minor; ssize_t tlen = 0; char *sep; struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id); @@ -575,6 +582,7 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size) if (len <= 0) return -EINVAL; do { enum vers_op cmd; + unsigned minor; sign = *vers; if (sign == '+' || sign == '-') num = simple_strtol((vers+1), &minorp, 0); @@ -585,8 +593,8 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size) return -EINVAL; if (kstrtouint(minorp+1, 0, &minor) < 0) return -EINVAL; - } else - minor = 0; + } + cmd = sign == '-' ? NFSD_CLEAR : NFSD_SET; switch(num) { case 2: @@ -594,8 +602,20 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size) nfsd_vers(num, cmd); break; case 4: - if (nfsd_minorversion(minor, cmd) >= 0) - break; + if (*minorp == '.') { + if (nfsd_minorversion(minor, cmd) < 0) + return -EINVAL; + } else if ((cmd == NFSD_SET) != nfsd_vers(num, NFSD_TEST)) { + /* + * Either we have +4 and no minors are enabled, + * or we have -4 and at least one minor is enabled. + * In either case, propagate 'cmd' to all minors. + */ + minor = 0; + while (nfsd_minorversion(minor, cmd) >= 0) + minor++; + } + break; default: return -EINVAL; } @@ -612,9 +632,11 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size) sep = ""; remaining = SIMPLE_TRANSACTION_LIMIT; for (num=2 ; num <= 4 ; num++) { + int minor; if (!nfsd_vers(num, NFSD_AVAIL)) continue; - minor = 0; + + minor = -1; do { len = nfsd_print_version_support(buf, remaining, sep, num, minor); @@ -624,7 +646,8 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size) buf += len; tlen += len; minor++; - sep = " "; + if (len) + sep = " "; } while (num == 4 && minor <= NFSD_SUPPORTED_MINOR_VERSION); } out: