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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37CEDC433EF for ; Mon, 6 Sep 2021 14:39:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1218A60EE6 for ; Mon, 6 Sep 2021 14:39:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243728AbhIFOjL (ORCPT ); Mon, 6 Sep 2021 10:39:11 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:19013 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243551AbhIFOi6 (ORCPT ); Mon, 6 Sep 2021 10:38:58 -0400 Received: from dggeme754-chm.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4H39rJ4zg3zbmG5; Mon, 6 Sep 2021 22:33:52 +0800 (CST) Received: from huawei.com (10.175.127.227) by dggeme754-chm.china.huawei.com (10.3.19.100) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.8; Mon, 6 Sep 2021 22:37:51 +0800 From: Ye Bin To: , , CC: , , Ye Bin Subject: [PATCH -next 6/6] ext4: fix possible store wrong check interval value in disk when umount Date: Mon, 6 Sep 2021 22:47:54 +0800 Message-ID: <20210906144754.2601607-7-yebin10@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210906144754.2601607-1-yebin10@huawei.com> References: <20210906144754.2601607-1-yebin10@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggeme754-chm.china.huawei.com (10.3.19.100) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Test follow steps: 1. mkfs.ext4 /dev/sda -O mmp 2. mount /dev/sda /mnt 3. wait for about 1 minute 4. umount mnt 5. debugfs /dev/sda 6. dump_mmp 7. fsck.ext4 /dev/sda I found 'check_interval' is range in [5, 10]. And sometime run fsck print "MMP interval is 10 seconds and total wait time is 42 seconds. Please wait...". kmmpd: ... if (diff < mmp_update_interval * HZ) schedule_timeout_interruptible(mmp_update_interval * HZ - diff); diff = jiffies - last_update_time; ... mmp_check_interval = max(min(EXT4_MMP_CHECK_MULT * diff / HZ, EXT4_MMP_MAX_CHECK_INTERVAL), EXT4_MMP_MIN_CHECK_INTERVAL); mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval); ... We will call ext4_stop_mmpd to stop kmmpd kthread when umount, and schedule_timeout_interruptible will be interrupted, so 'diff' maybe little than mmp_update_interval. Then mmp_check_interval will range in [EXT4_MMP_MAX_CHECK_INTERVAL, EXT4_MMP_CHECK_MULT * diff / HZ]. To solve this issue, if 'diff' little then mmp_update_interval * HZ just break loop, don't update check interval. Signed-off-by: Ye Bin --- fs/ext4/mmp.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c index eed854bb6194..41c0a03019db 100644 --- a/fs/ext4/mmp.c +++ b/fs/ext4/mmp.c @@ -205,6 +205,14 @@ static int kmmpd(void *data) schedule_timeout_interruptible(mmp_update_interval * HZ - diff); diff = jiffies - last_update_time; + /* If 'diff' little 'than mmp_update_interval * HZ', it + * means someone call ext4_stop_mmpd to stop kmmpd + * kthread. We don't need to update mmp_check_interval + * any more, as 'diff' is not exact value. + */ + if (unlikely(diff < mmp_update_interval * HZ && + kthread_should_stop())) + break; } /* -- 2.31.1