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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 B9F97C4332F for ; Thu, 9 Sep 2021 02:20:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B2D161139 for ; Thu, 9 Sep 2021 02:20:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348667AbhIICVi (ORCPT ); Wed, 8 Sep 2021 22:21:38 -0400 Received: from out1.migadu.com ([91.121.223.63]:43867 "EHLO out1.migadu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241774AbhIICVe (ORCPT ); Wed, 8 Sep 2021 22:21:34 -0400 Subject: Re: [PATCH -next 2/6] ext4: introduce last_check_time record previous check time DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1631154023; 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=IeoyoE9nFc/8AJQHWEf/XYpBZje7kZZE7EX8W6rfGjg=; b=RmdY+cIxfIOwQ3zyK++oDwDDsCi3JUNnNhKXAV7x5UQQe4+lNv1PzneVIawfLxyoJR7T5C WzKG70apqu3nySSDVh+iEZ70etsEpG0gMgtOjMfOo3jhQT0NuRoxgMIVnatDjQA640cVEJ JfRt1KcJFTfl2jnYbPOzRDLcJIHkxZw= To: Ye Bin , tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org Cc: linux-kernel@vger.kernel.org, jack@suse.cz References: <20210906144754.2601607-1-yebin10@huawei.com> <20210906144754.2601607-3-yebin10@huawei.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Guoqing Jiang Message-ID: <03bd0982-f0ad-78b4-7b98-cbfdbab9deec@linux.dev> Date: Thu, 9 Sep 2021 10:20:17 +0800 MIME-Version: 1.0 In-Reply-To: <20210906144754.2601607-3-yebin10@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: guoqing.jiang@linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/6/21 10:47 PM, Ye Bin wrote: > kmmpd: > ... > diff = jiffies - last_update_time; > if (diff > mmp_check_interval * HZ) { > ... > As "mmp_check_interval = 2 * mmp_update_interval", 'diff' always little > than 'mmp_update_interval', so there will never trigger detection. > Introduce last_check_time record previous check time. > > Signed-off-by: Ye Bin > --- > fs/ext4/mmp.c | 14 +++++++++----- > 1 file changed, 9 insertions(+), 5 deletions(-) > > diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c > index 12af6dc8457b..89797f12a815 100644 > --- a/fs/ext4/mmp.c > +++ b/fs/ext4/mmp.c > @@ -152,6 +152,7 @@ static int kmmpd(void *data) > int mmp_update_interval = le16_to_cpu(es->s_mmp_update_interval); > unsigned mmp_check_interval; > unsigned long last_update_time; > + unsigned long last_check_time; > unsigned long diff; > int retval = 0; > > @@ -170,6 +171,7 @@ static int kmmpd(void *data) > > memcpy(mmp->mmp_nodename, init_utsname()->nodename, > sizeof(mmp->mmp_nodename)); > + last_update_time = jiffies; > > while (!kthread_should_stop() && !sb_rdonly(sb)) { > if (!ext4_has_feature_mmp(sb)) { > @@ -198,17 +200,18 @@ static int kmmpd(void *data) > } > > diff = jiffies - last_update_time; > - if (diff < mmp_update_interval * HZ) > + if (diff < mmp_update_interval * HZ) { > schedule_timeout_interruptible(mmp_update_interval * > HZ - diff); > + diff = jiffies - last_update_time; > + } > > /* > * We need to make sure that more than mmp_check_interval > - * seconds have not passed since writing. If that has happened > - * we need to check if the MMP block is as we left it. > + * seconds have not passed since check. If that has happened > + * we need to check if the MMP block is as we write it. > */ > - diff = jiffies - last_update_time; > - if (diff > mmp_check_interval * HZ) { > + if (jiffies - last_check_time > mmp_check_interval * HZ) { Before the above checking, seems last_check_time is not initialized yet. > struct buffer_head *bh_check = NULL; > struct mmp_struct *mmp_check; > > @@ -234,6 +237,7 @@ static int kmmpd(void *data) > goto wait_to_exit; > } > put_bh(bh_check); > + last_check_time = jiffies; > } > > /* Thanks, Guoqing