From patchwork Thu Nov 29 05:55:37 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sasha Levin X-Patchwork-Id: 10704011 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2630814E2 for ; Thu, 29 Nov 2018 06:12:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 17F522E778 for ; Thu, 29 Nov 2018 06:12:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0ADE02E78D; Thu, 29 Nov 2018 06:12:17 +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=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,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 A29F52E778 for ; Thu, 29 Nov 2018 06:12:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727535AbeK2RDw (ORCPT ); Thu, 29 Nov 2018 12:03:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:38210 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728107AbeK2RDw (ORCPT ); Thu, 29 Nov 2018 12:03:52 -0500 Received: from sasha-vm.mshome.net (unknown [37.142.5.207]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 05708208E7; Thu, 29 Nov 2018 05:59:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1543471181; bh=XZIMpldLM58zbtDq4L6xLhMKLPBlcBIuG/V0QQiwxFY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HrYHqPnvgZjDTqMkWU2e7SYBevvDgvipGP/lz6Ue+rrM3fiRFOOxbI53xc21em+ug pyTzb5wUKcCU0LwnRtjKPyV+mj1ELkrl53SNctb+pG4b6ZEPiOYqrjhahBhkTq+2Mt a2QzYbuoTJ/d328JonSpunUIGfINvs8y3jWoIj1c= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Trond Myklebust , Sasha Levin , linux-nfs@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 46/68] NFSv4: Fix a NFSv4 state manager deadlock Date: Thu, 29 Nov 2018 00:55:37 -0500 Message-Id: <20181129055559.159228-46-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181129055559.159228-1-sashal@kernel.org> References: <20181129055559.159228-1-sashal@kernel.org> 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 From: Trond Myklebust [ Upstream commit aeabb3c96186a0f944fc2b1f25c84d5eb3a93fa9 ] Fix a deadlock whereby the NFSv4 state manager can get stuck in the delegation return code, waiting for a layout return to complete in another thread. If the server reboots before that other thread completes, then we need to be able to start a second state manager thread in order to perform recovery. Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin --- fs/nfs/nfs4_fs.h | 2 ++ fs/nfs/nfs4state.c | 16 +++++++++++----- 2 files changed, 13 insertions(+), 5 deletions(-) diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h index 3a6904173214..63287d911c08 100644 --- a/fs/nfs/nfs4_fs.h +++ b/fs/nfs/nfs4_fs.h @@ -41,6 +41,8 @@ enum nfs4_client_state { NFS4CLNT_MOVED, NFS4CLNT_LEASE_MOVED, NFS4CLNT_DELEGATION_EXPIRED, + NFS4CLNT_RUN_MANAGER, + NFS4CLNT_DELEGRETURN_RUNNING, }; #define NFS4_RENEW_TIMEOUT 0x01 diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index 18920152da14..d2f645d34eb1 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -1210,6 +1210,7 @@ void nfs4_schedule_state_manager(struct nfs_client *clp) struct task_struct *task; char buf[INET6_ADDRSTRLEN + sizeof("-manager") + 1]; + set_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state); if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) != 0) return; __module_get(THIS_MODULE); @@ -2485,6 +2486,7 @@ static void nfs4_state_manager(struct nfs_client *clp) /* Ensure exclusive access to NFSv4 state */ do { + clear_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state); if (test_bit(NFS4CLNT_PURGE_STATE, &clp->cl_state)) { section = "purge state"; status = nfs4_purge_lease(clp); @@ -2575,14 +2577,18 @@ static void nfs4_state_manager(struct nfs_client *clp) } nfs4_end_drain_session(clp); - if (test_and_clear_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state)) { - nfs_client_return_marked_delegations(clp); - continue; + nfs4_clear_state_manager_bit(clp); + + if (!test_and_set_bit(NFS4CLNT_DELEGRETURN_RUNNING, &clp->cl_state)) { + if (test_and_clear_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state)) { + nfs_client_return_marked_delegations(clp); + set_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state); + } + clear_bit(NFS4CLNT_DELEGRETURN_RUNNING, &clp->cl_state); } - nfs4_clear_state_manager_bit(clp); /* Did we race with an attempt to give us more work? */ - if (clp->cl_state == 0) + if (!test_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state)) return; if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) != 0) return;