From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B0ACD8494 for ; Thu, 5 Jan 2023 12:59:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 19B24C433EF; Thu, 5 Jan 2023 12:59:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672923599; bh=kT+tZkfoPA2CK4HYdymBpTMcoWrO+1CZzLouiah/qPE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z2daSca/sR0JyY1zH3ycRn1PkjTsV7iJC9vi0x3QRPPmfVvnf+HGbydh03Ghot1Sd 8JCkpdFJY1PAHysZTxzjEv2dz1weHV3DfuCGa3mXCpvWVIM2GwY/gssnfde3dao4uG sDVLcs/k6u3vVfLvI2jFEpvIh13FlKEoeFPzGP9Y= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Trond Myklebust , Sasha Levin Subject: [PATCH 4.9 072/251] NFSv4: Fix a deadlock between nfs4_open_recover_helper() and delegreturn Date: Thu, 5 Jan 2023 13:53:29 +0100 Message-Id: <20230105125338.070611225@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230105125334.727282894@linuxfoundation.org> References: <20230105125334.727282894@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Trond Myklebust [ Upstream commit 51069e4aef6257b0454057359faed0ab0c9af083 ] If we're asked to recover open state while a delegation return is outstanding, then the state manager thread cannot use a cached open, so if the server returns a delegation, we can end up deadlocked behind the pending delegreturn. To avoid this problem, let's just ask the server not to give us a delegation unless we're explicitly reclaiming one. Fixes: be36e185bd26 ("NFSv4: nfs4_open_recover_helper() must set share access") Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin --- fs/nfs/nfs4proc.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 5baf6ed7732d..4771fc16d7d1 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -1822,18 +1822,18 @@ static struct nfs4_opendata *nfs4_open_recoverdata_alloc(struct nfs_open_context } static int nfs4_open_recover_helper(struct nfs4_opendata *opendata, - fmode_t fmode) + fmode_t fmode) { struct nfs4_state *newstate; + struct nfs_server *server = NFS_SB(opendata->dentry->d_sb); + int openflags = opendata->o_arg.open_flags; int ret; if (!nfs4_mode_match_open_stateid(opendata->state, fmode)) return 0; - opendata->o_arg.open_flags = 0; opendata->o_arg.fmode = fmode; - opendata->o_arg.share_access = nfs4_map_atomic_open_share( - NFS_SB(opendata->dentry->d_sb), - fmode, 0); + opendata->o_arg.share_access = + nfs4_map_atomic_open_share(server, fmode, openflags); memset(&opendata->o_res, 0, sizeof(opendata->o_res)); memset(&opendata->c_res, 0, sizeof(opendata->c_res)); nfs4_init_opendata_res(opendata); @@ -2411,10 +2411,15 @@ static int _nfs4_open_expired(struct nfs_open_context *ctx, struct nfs4_state *s struct nfs4_opendata *opendata; int ret; - opendata = nfs4_open_recoverdata_alloc(ctx, state, - NFS4_OPEN_CLAIM_FH); + opendata = nfs4_open_recoverdata_alloc(ctx, state, NFS4_OPEN_CLAIM_FH); if (IS_ERR(opendata)) return PTR_ERR(opendata); + /* + * We're not recovering a delegation, so ask for no delegation. + * Otherwise the recovery thread could deadlock with an outstanding + * delegation return. + */ + opendata->o_arg.open_flags = O_DIRECT; ret = nfs4_open_recover(opendata, state); if (ret == -ESTALE) d_drop(ctx->dentry); -- 2.35.1