Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx1.redhat.com ([209.132.183.28]:22212 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751888Ab3DJLLY (ORCPT ); Wed, 10 Apr 2013 07:11:24 -0400 Message-ID: <516548D8.3070707@redhat.com> Date: Wed, 10 Apr 2013 12:11:20 +0100 From: Jose Castillo MIME-Version: 1.0 To: "J. Bruce Fields" CC: Linux NFS Mailing list , steved@redhat.com Subject: Re: [PATCH] Add the missing '$' in auth_unix_ip() References: <1365522899-29123-1-git-send-email-jcastillo@redhat.com> <20130409191113.GC3800@fieldses.org> In-Reply-To: <20130409191113.GC3800@fieldses.org> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-nfs-owner@vger.kernel.org List-ID: On 04/09/2013 08:11 PM, J. Bruce Fields wrote: > Could you explain a little more? > > I assume this is something I forgot to do as part of > c2544b77566690ebec32a2d47c9249548b1a0941 "mountd: prepend '$' to > make use_ipaddr clients self-describing" but I haven't thought > about that in a while.... > Hello, Yes, sorry, a bit more of background: We found this problem because NFS clients to a RHEL6 NFS server were experiencing periods of ESTALE errors after being mounted and initially working successfully. Tests were run which snapshotted the nfs/sunrpc caches before and after the issue, and it was found that the '$' character at the beginning of the ID strings, used when in use_ipaddr mode, was getting lost: GOOD, while mount was working: #class IP domain # expiry=1362416801 refcnt=2 flags=1 nfsd 1.2.3.4 $1.2.3.4 BAD, after mount started returning ESTALE: #class IP domain # expiry=1362418641 refcnt=2 flags=1 nfsd 1.2.3.4 1.2.3.4 This would then cause the export checks to fail by passing '1.2.3.4' instead of '$1.2.3.4' up to rpc.mountd. The problem appears to be in the auth_unix_ip() function when renewing the auth.unix.ip cache entry. It would fail to add the '$' character back to the beginning of the string used for the domain string, breaking the use_ipaddr mode. The issue is reliably repeatable with large numbers of exports and netgroups to cause rpc.mountd to enter use_ipaddr mode. Steps to reproduce: 1. Export several hundred exports each with its own unique netgroup 2. Mount from a client (NFS3). check /proc/net/rpc/auth.unix.ip/content to ensure the '$' character is there from use_ipaddr mode. 3. Wait long enough for the entry to expire (1 hour was used), and try and access a file from the client. It returned ESTALE and the /proc/net/rpc/auth.unix.ip/content was now missing the '$' character. Actual results: Mount returns ESTALE on the client after being mounted for an extended period of time. Expected results: File access should succeed on the mount. The patch was tested in a reproduction environment, and the issue could no longer be reproduced. > --b. > > On Tue, Apr 09, 2013 at 04:54:59PM +0100, Jose Castillo wrote: >> Signed-off-by: Jose Castillo --- >> utils/mountd/cache.c | 10 ++++++---- 1 file changed, 6 >> insertions(+), 4 deletions(-) >> >> diff --git a/utils/mountd/cache.c b/utils/mountd/cache.c index >> 978698d..e1027f3 100644 --- a/utils/mountd/cache.c +++ >> b/utils/mountd/cache.c @@ -80,7 +80,7 @@ static void >> auth_unix_ip(FILE *f) */ char *cp; char class[20]; - char >> ipaddr[INET6_ADDRSTRLEN]; + char ipaddr[INET6_ADDRSTRLEN + 1]; >> char *client = NULL; struct addrinfo *tmp = NULL; if >> (readline(fileno(f), &lbuf, &lbuflen) != 1) @@ -94,7 +94,7 @@ >> static void auth_unix_ip(FILE *f) strcmp(class, "nfsd") != 0) >> return; >> >> - if (qword_get(&cp, ipaddr, sizeof(ipaddr)) <= 0) + if >> (qword_get(&cp, ipaddr, sizeof(ipaddr) - 1) <= 0) return; >> >> tmp = host_pton(ipaddr); @@ -116,9 +116,11 @@ static void >> auth_unix_ip(FILE *f) qword_print(f, "nfsd"); qword_print(f, >> ipaddr); qword_printtimefrom(f, DEFAULT_TTL); - if (use_ipaddr) + >> if (use_ipaddr) { + memmove(ipaddr + 1, ipaddr, strlen(ipaddr) + >> 1); + ipaddr[0] = '$'; qword_print(f, ipaddr); - else if >> (client) + } else if (client) qword_print(f, >> *client?client:"DEFAULT"); qword_eol(f); xlog(D_CALL, >> "auth_unix_ip: client %p '%s'", client, client?client: >> "DEFAULT"); -- 1.7.11.7 >> >> -- 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