From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D377EB64D7 for ; Tue, 13 Jun 2023 14:44:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241822AbjFMOoG (ORCPT ); Tue, 13 Jun 2023 10:44:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56066 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239644AbjFMOoE (ORCPT ); Tue, 13 Jun 2023 10:44:04 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3B5451732 for ; Tue, 13 Jun 2023 07:43:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1686667404; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qCAk+GrfYv2LlZeL9R4DyIt9sUEULTjaibnxzpvOXzU=; b=UrSyi06Ro7IWOqWp9UL7C/Y9Bm/8nLjtV/Q+j8sct40eVtfLWm+OKAWhtiVmd/TVe6+1al J/zYY9rAV2kusCEVIPNqLN2dBZI6Nmiyxzoo+P0D+29M0fhs+pLocEYX+9aoDNOrIJrreo FiJagTqxcTiUBqLj7wIq6mk2OhSYMzo= Received: from mail-pj1-f71.google.com (mail-pj1-f71.google.com [209.85.216.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-418-_r6EtMvVNpSVmQp2_zvFnQ-1; Tue, 13 Jun 2023 10:43:22 -0400 X-MC-Unique: _r6EtMvVNpSVmQp2_zvFnQ-1 Received: by mail-pj1-f71.google.com with SMTP id 98e67ed59e1d1-25bd6f23032so2056737a91.0 for ; Tue, 13 Jun 2023 07:43:22 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686667401; x=1689259401; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=qCAk+GrfYv2LlZeL9R4DyIt9sUEULTjaibnxzpvOXzU=; b=FOwGVUDV/7klIcTXiBqcPv6Q+RkdVZlnhkyZ69FE9W+i+fHhC0vdxDMIZDrdoRHzfn SDMMaRDc1oAbz5knm1LNvotj1yaqzTDa8aOh1uL1w4lByDVHhnnSjbPpppj4N+zY7Cax uIpI8B/UIVEZzajdKU8SxluERECsVAjGcVu30aY3reIqHLraDBUtg02Lug+SZBQuZOMH W/ulKYtog9G3S+zezK4hR3O3huktOYe9GHSXsEaIZiwyQHqCGsryP9MCe6pjgSogolbG fnuAcDbCQaHL5cjO/UwCuJz67nuzVO5ZOX5y5bcNjpEJP0beayN6WGbm88bvgM/m5A/K Q6ZQ== X-Gm-Message-State: AC+VfDxjBawPIbyt0Fe49rKQznJxzcL+ndKP5cXHJkt3jaB/Lb8hWIy7 JIKy/a/N2qcMU0Zfp/SQ+e/3tlOf5Z8UK1QTI53ORY4tR2CXXsFY9lxqtU8CY2d51VNnI1gfLJS g88MT8M1tUJ9PLeKK1zGm+/f1 X-Received: by 2002:a17:90b:364c:b0:25b:e311:14b9 with SMTP id nh12-20020a17090b364c00b0025be31114b9mr5583551pjb.29.1686667401476; Tue, 13 Jun 2023 07:43:21 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ7pzDK/dX7LQKc/Z1gmMKhXdFjH/ZJbgm6TymQSc9JNchoVhSaDhMC+a+dsmHcntgyeQR8+DA== X-Received: by 2002:a17:90b:364c:b0:25b:e311:14b9 with SMTP id nh12-20020a17090b364c00b0025be31114b9mr5583529pjb.29.1686667401155; Tue, 13 Jun 2023 07:43:21 -0700 (PDT) Received: from [10.72.13.126] ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id s23-20020a17090a1c1700b0025be4c602d5sm4095009pjs.38.2023.06.13.07.43.17 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 13 Jun 2023 07:43:20 -0700 (PDT) Message-ID: Date: Tue, 13 Jun 2023 22:43:11 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.11.2 Subject: Re: [dm-devel] [PATCH -next v2 3/6] md: add a mutex to synchronize idle and frozen in action_store() To: Yu Kuai , guoqing.jiang@linux.dev, agk@redhat.com, snitzer@kernel.org, dm-devel@redhat.com, song@kernel.org Cc: yi.zhang@huawei.com, yangerkun@huawei.com, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, yukuai3@huawei.com References: <20230529132037.2124527-1-yukuai1@huaweicloud.com> <20230529132037.2124527-4-yukuai1@huaweicloud.com> From: Xiao Ni In-Reply-To: <20230529132037.2124527-4-yukuai1@huaweicloud.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2023/5/29 下午9:20, Yu Kuai 写道: > From: Yu Kuai > > Currently, for idle and frozen, action_store will hold 'reconfig_mutex' > and call md_reap_sync_thread() to stop sync thread, however, this will > cause deadlock (explained in the next patch). In order to fix the > problem, following patch will release 'reconfig_mutex' and wait on > 'resync_wait', like md_set_readonly() and do_md_stop() does. > > Consider that action_store() will set/clear 'MD_RECOVERY_FROZEN' > unconditionally, which might cause unexpected problems, for example, > frozen just set 'MD_RECOVERY_FROZEN' and is still in progress, while > 'idle' clear 'MD_RECOVERY_FROZEN' and new sync thread is started, which > might starve in progress frozen. A mutex is added to synchronize idle > and frozen from action_store(). > > Signed-off-by: Yu Kuai > --- > drivers/md/md.c | 5 +++++ > drivers/md/md.h | 3 +++ > 2 files changed, 8 insertions(+) > > diff --git a/drivers/md/md.c b/drivers/md/md.c > index 23e8e7eae062..63a993b52cd7 100644 > --- a/drivers/md/md.c > +++ b/drivers/md/md.c > @@ -644,6 +644,7 @@ void mddev_init(struct mddev *mddev) > mutex_init(&mddev->open_mutex); > mutex_init(&mddev->reconfig_mutex); > mutex_init(&mddev->delete_mutex); > + mutex_init(&mddev->sync_mutex); > mutex_init(&mddev->bitmap_info.mutex); > INIT_LIST_HEAD(&mddev->disks); > INIT_LIST_HEAD(&mddev->all_mddevs); > @@ -4785,14 +4786,18 @@ static void stop_sync_thread(struct mddev *mddev) > > static void idle_sync_thread(struct mddev *mddev) > { > + mutex_lock(&mddev->sync_mutex); > clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); > stop_sync_thread(mddev); > + mutex_unlock(&mddev->sync_mutex); > } > > static void frozen_sync_thread(struct mddev *mddev) > { > + mutex_init(&mddev->delete_mutex); typo error? It should be mutex_lock(&mddev->sync_mutex); ? Regards Xiao > set_bit(MD_RECOVERY_FROZEN, &mddev->recovery); > stop_sync_thread(mddev); > + mutex_unlock(&mddev->sync_mutex); > } > > static ssize_t > diff --git a/drivers/md/md.h b/drivers/md/md.h > index bfd2306bc750..2fa903de5bd0 100644 > --- a/drivers/md/md.h > +++ b/drivers/md/md.h > @@ -537,6 +537,9 @@ struct mddev { > /* Protect the deleting list */ > struct mutex delete_mutex; > > + /* Used to synchronize idle and frozen for action_store() */ > + struct mutex sync_mutex; > + > bool has_superblocks:1; > bool fail_last_dev:1; > bool serialize_policy:1;