From patchwork Fri Feb 2 22:13:19 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Heinz Mauelshagen X-Patchwork-Id: 10198161 X-Patchwork-Delegate: snitzer@redhat.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 48C0860388 for ; Fri, 2 Feb 2018 22:13:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2DC5A28F7C for ; Fri, 2 Feb 2018 22:13:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2284C28F92; Fri, 2 Feb 2018 22:13:44 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id B532628F7C for ; Fri, 2 Feb 2018 22:13:43 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 458AC87624; Fri, 2 Feb 2018 22:13:42 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id ED78C6F105; Fri, 2 Feb 2018 22:13:40 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 584805FBD8; Fri, 2 Feb 2018 22:13:38 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id w12MDaRe013755 for ; Fri, 2 Feb 2018 17:13:36 -0500 Received: by smtp.corp.redhat.com (Postfix) id B23D66A97B; Fri, 2 Feb 2018 22:13:36 +0000 (UTC) Delivered-To: dm-devel@redhat.com Received: from redhat.com.com (ovpn-117-145.ams2.redhat.com [10.36.117.145]) by smtp.corp.redhat.com (Postfix) with ESMTP id 961536766F; Fri, 2 Feb 2018 22:13:33 +0000 (UTC) From: Heinz Mauelshagen To: heinzm@redhat.com, dm-devel@redhat.com, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, shli@kernel.org Date: Fri, 2 Feb 2018 23:13:19 +0100 Message-Id: <054eff295e0cd2df2b11a3f9ba3b3d66e89beb47.1517609290.git.heinzm@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-loop: dm-devel@redhat.com Subject: [dm-devel] [PATCH] md: fix md_write_start() deadlock w/o metadata devices X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Fri, 02 Feb 2018 22:13:43 +0000 (UTC) X-Virus-Scanned: ClamAV using ClamSMTP If no metadata devices are configured on raid1/4/5/6/10 (e.g. via dm-raid), md_write_start() unconditionally waits for superblocks to be written thus deadlocking. Fix introduces mddev->has_superblocks bool, defines it in md_run() and checks for it in md_write_start() to conditionally avoid waiting. Once on it, check for non-existing superblocks in md_super_write(). Link: https://bugzilla.kernel.org/show_bug.cgi?id=198647 Fixes: cc27b0c78c796 ("md: fix deadlock between mddev_suspend() and md_write_start()") Signed-off-by: Heinz Mauelshagen --- drivers/md/md.c | 10 ++++++++++ drivers/md/md.h | 2 ++ 2 files changed, 12 insertions(+) diff --git a/drivers/md/md.c b/drivers/md/md.c index 0081ace39a64..8a7e7034962c 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -801,6 +801,9 @@ void md_super_write(struct mddev *mddev, struct md_rdev *rdev, struct bio *bio; int ff = 0; + if (!page) + return; + if (test_bit(Faulty, &rdev->flags)) return; @@ -5452,6 +5455,7 @@ int md_run(struct mddev *mddev) * the only valid external interface is through the md * device. */ + mddev->has_superblocks = false; rdev_for_each(rdev, mddev) { if (test_bit(Faulty, &rdev->flags)) continue; @@ -5465,6 +5469,9 @@ int md_run(struct mddev *mddev) set_disk_ro(mddev->gendisk, 1); } + if (rdev->sb_page) + mddev->has_superblocks = true; + /* perform some consistency tests on the device. * We don't want the data to overlap the metadata, * Internal Bitmap issues have been handled elsewhere. @@ -8049,6 +8056,7 @@ EXPORT_SYMBOL(md_done_sync); bool md_write_start(struct mddev *mddev, struct bio *bi) { int did_change = 0; + if (bio_data_dir(bi) != WRITE) return true; @@ -8081,6 +8089,8 @@ bool md_write_start(struct mddev *mddev, struct bio *bi) rcu_read_unlock(); if (did_change) sysfs_notify_dirent_safe(mddev->sysfs_state); + if (!mddev->has_superblocks) + return true; wait_event(mddev->sb_wait, !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) || mddev->suspended); diff --git a/drivers/md/md.h b/drivers/md/md.h index 58cd20a5e85e..fbc925cce810 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -468,6 +468,8 @@ struct mddev { void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev); struct md_cluster_info *cluster_info; unsigned int good_device_nr; /* good device num within cluster raid */ + + bool has_superblocks:1; }; enum recovery_flags {