From owner-dev-commits-src-branches@freebsd.org Sat Apr 24 22:31:11 2021 Return-Path: Delivered-To: dev-commits-src-branches@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 89DB05E2D3B; Sat, 24 Apr 2021 22:31:11 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4FSQqM3Xvyz3qpK; Sat, 24 Apr 2021 22:31:11 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 6C5B37B9; Sat, 24 Apr 2021 22:31:11 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 13OMVBqG024796; Sat, 24 Apr 2021 22:31:11 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 13OMVBQ3024795; Sat, 24 Apr 2021 22:31:11 GMT (envelope-from git) Date: Sat, 24 Apr 2021 22:31:11 GMT Message-Id: <202104242231.13OMVBQ3024795@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Rick Macklem Subject: git: 4543735a5f5c - stable/13 - nfsd: fix replies from session cache for multiple retries MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: rmacklem X-Git-Repository: src X-Git-Refname: refs/heads/stable/13 X-Git-Reftype: branch X-Git-Commit: 4543735a5f5c4ecb0f73382fd3a84fb4b4af169f Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-branches@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commits to the stable branches of the FreeBSD src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 24 Apr 2021 22:31:11 -0000 The branch stable/13 has been updated by rmacklem: URL: https://cgit.FreeBSD.org/src/commit/?id=4543735a5f5c4ecb0f73382fd3a84fb4b4af169f commit 4543735a5f5c4ecb0f73382fd3a84fb4b4af169f Author: Rick Macklem AuthorDate: 2021-04-10 22:50:25 +0000 Commit: Rick Macklem CommitDate: 2021-04-24 22:27:26 +0000 nfsd: fix replies from session cache for multiple retries Recent testing of network partitioning a FreeBSD NFSv4.1 server from a Linux NFSv4.1 client identified problems with both the FreeBSD server and Linux client. Commit 05a39c2c1c18 fixed replying with the cached reply in in the session slot if same session slot sequence#. However, the code uses the reply and, as such, will fail for a subsequent retry of the RPC. A subsequent retry would be an extremely rare event, but this patch fixes this, so long as m_copym(..M_NOWAIT) does not fail, which should also be a rare event. This fix affects the exceedingly rare case where a NFSv4 client retries a non-idempotent RPC, such as a lock operation, multiple times. Note that retries only occur after the client has needed to create a new TCP connection, with a new TCP connection for each retry. (cherry picked from commit 22cefe3d8378f58adcdbb2c7589b9f30c2a38315) --- sys/fs/nfs/nfs_commonsubs.c | 34 ++++++++++++++++++++++++++++++---- 1 file changed, 30 insertions(+), 4 deletions(-) diff --git a/sys/fs/nfs/nfs_commonsubs.c b/sys/fs/nfs/nfs_commonsubs.c index e9b2af17d8b4..43bb396d9cfd 100644 --- a/sys/fs/nfs/nfs_commonsubs.c +++ b/sys/fs/nfs/nfs_commonsubs.c @@ -4619,6 +4619,7 @@ int nfsv4_seqsession(uint32_t seqid, uint32_t slotid, uint32_t highslot, struct nfsslot *slots, struct mbuf **reply, uint16_t maxslot) { + struct mbuf *m; int error; error = 0; @@ -4632,8 +4633,14 @@ nfsv4_seqsession(uint32_t seqid, uint32_t slotid, uint32_t highslot, error = NFSERR_DELAY; else if (slots[slotid].nfssl_reply != NULL) { if (reply != NULL) { - *reply = slots[slotid].nfssl_reply; - slots[slotid].nfssl_reply = NULL; + m = m_copym(slots[slotid].nfssl_reply, 0, + M_COPYALL, M_NOWAIT); + if (m != NULL) + *reply = m; + else { + *reply = slots[slotid].nfssl_reply; + slots[slotid].nfssl_reply = NULL; + } } slots[slotid].nfssl_inprog = 1; error = NFSERR_REPLYFROMCACHE; @@ -4660,10 +4667,29 @@ void nfsv4_seqsess_cacherep(uint32_t slotid, struct nfsslot *slots, int repstat, struct mbuf **rep) { + struct mbuf *m; if (repstat == NFSERR_REPLYFROMCACHE) { - *rep = slots[slotid].nfssl_reply; - slots[slotid].nfssl_reply = NULL; + if (slots[slotid].nfssl_reply != NULL) { + /* + * We cannot sleep here, but copy will usually + * succeed. + */ + m = m_copym(slots[slotid].nfssl_reply, 0, M_COPYALL, + M_NOWAIT); + if (m != NULL) + *rep = m; + else { + /* + * Multiple retries would be extremely rare, + * so using the cached reply will likely + * be ok. + */ + *rep = slots[slotid].nfssl_reply; + slots[slotid].nfssl_reply = NULL; + } + } else + *rep = NULL; } else { if (slots[slotid].nfssl_reply != NULL) m_freem(slots[slotid].nfssl_reply);