From patchwork Thu Jul 24 08:58:00 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Junxiao Bi X-Patchwork-Id: 4615111 Return-Path: X-Original-To: patchwork-ocfs2-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 62EF4C0514 for ; Thu, 24 Jul 2014 08:59:25 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 76A82201BC for ; Thu, 24 Jul 2014 08:59:24 +0000 (UTC) Received: from userp1040.oracle.com (userp1040.oracle.com [156.151.31.81]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9C8AC201BB for ; Thu, 24 Jul 2014 08:59:22 +0000 (UTC) Received: from acsinet21.oracle.com (acsinet21.oracle.com [141.146.126.237]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id s6O8wdvt006291 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 24 Jul 2014 08:58:40 GMT Received: from oss.oracle.com (oss-external.oracle.com [137.254.96.51]) by acsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id s6O8wZLa022449 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 24 Jul 2014 08:58:35 GMT Received: from localhost ([127.0.0.1] helo=oss.oracle.com) by oss.oracle.com with esmtp (Exim 4.63) (envelope-from ) id 1XAErD-0008RV-8v; Thu, 24 Jul 2014 01:58:35 -0700 Received: from acsinet22.oracle.com ([141.146.126.238]) by oss.oracle.com with esmtp (Exim 4.63) (envelope-from ) id 1XAEqs-0008Qf-Vg for ocfs2-devel@oss.oracle.com; Thu, 24 Jul 2014 01:58:15 -0700 Received: from userz7021.oracle.com (userz7021.oracle.com [156.151.31.85]) by acsinet22.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id s6O8wD1r006784 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL); Thu, 24 Jul 2014 08:58:14 GMT Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userz7021.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id s6O8wDka010866; Thu, 24 Jul 2014 08:58:13 GMT Received: from bijx-OptiPlex-780.cn.oracle.com (/10.182.39.153) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 24 Jul 2014 01:58:13 -0700 From: Junxiao Bi To: ocfs2-devel@oss.oracle.com Date: Thu, 24 Jul 2014 16:58:00 +0800 Message-Id: <1406192280-6643-1-git-send-email-junxiao.bi@oracle.com> X-Mailer: git-send-email 1.7.9.5 Cc: mfasheh@suse.com, joe.jin@oracle.com Subject: [Ocfs2-devel] [PATCH] ocfs2: fix journal commit deadlock X-BeenThere: ocfs2-devel@oss.oracle.com X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: ocfs2-devel-bounces@oss.oracle.com Errors-To: ocfs2-devel-bounces@oss.oracle.com X-Source-IP: acsinet21.oracle.com [141.146.126.237] X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP For buffer write, page lock will be got in write_begin and released in write_end, in ocfs2_write_end_nolock(), before it unlock the page in ocfs2_free_write_ctxt(), it calls ocfs2_run_deallocs(), this will ask for the read lock of journal->j_trans_barrier. Holding page lock and ask for journal->j_trans_barrier breaks the locking order. This will cause a deadlock with journal commit threads, ocfs2cmt will get write lock of journal->j_trans_barrier first, then it wakes up kjournald2 to do the commit work, at last it waits until done. To commit journal, kjournald2 needs flushing data first, it needs get the cache page lock. Since some ocfs2 cluster locks are holding by write process, this deadlock may hung the whole cluster. unlock pages before ocfs2_run_deallocs() can fix the locking order, also put unlock before ocfs2_commit_trans() to make page lock is unlocked before j_trans_barrier to preserve unlocking order. Signed-off-by: Junxiao Bi Cc: Reviewed-by: Wengang Wang --- fs/ocfs2/aops.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index 4a231a1..c04183b 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -894,7 +894,7 @@ void ocfs2_unlock_and_free_pages(struct page **pages, int num_pages) } } -static void ocfs2_free_write_ctxt(struct ocfs2_write_ctxt *wc) +static void ocfs2_unlock_pages(struct ocfs2_write_ctxt *wc) { int i; @@ -915,7 +915,11 @@ static void ocfs2_free_write_ctxt(struct ocfs2_write_ctxt *wc) page_cache_release(wc->w_target_page); } ocfs2_unlock_and_free_pages(wc->w_pages, wc->w_num_pages); +} +static void ocfs2_free_write_ctxt(struct ocfs2_write_ctxt *wc) +{ + ocfs2_unlock_pages(wc); brelse(wc->w_di_bh); kfree(wc); } @@ -2041,11 +2045,19 @@ out_write_size: ocfs2_update_inode_fsync_trans(handle, inode, 1); ocfs2_journal_dirty(handle, wc->w_di_bh); + /* unlock pages before dealloc since it needs acquiring j_trans_barrier + * lock, or it will cause a deadlock since journal commit threads holds + * this lock and will ask for the page lock when flushing the data. + * put it here to preserve the unlock order. + */ + ocfs2_unlock_pages(wc); + ocfs2_commit_trans(osb, handle); ocfs2_run_deallocs(osb, &wc->w_dealloc); - ocfs2_free_write_ctxt(wc); + brelse(wc->w_di_bh); + kfree(wc); return copied; }