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,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 61DC1C4321E for ; Sat, 11 Sep 2021 08:51:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 496A6611BF for ; Sat, 11 Sep 2021 08:51:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235501AbhIKIwT (ORCPT ); Sat, 11 Sep 2021 04:52:19 -0400 Received: from szxga08-in.huawei.com ([45.249.212.255]:16191 "EHLO szxga08-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235439AbhIKIwP (ORCPT ); Sat, 11 Sep 2021 04:52:15 -0400 Received: from dggeme754-chm.china.huawei.com (unknown [172.30.72.55]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4H65zL4vNNz1DGps; Sat, 11 Sep 2021 16:50:06 +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; Sat, 11 Sep 2021 16:51:01 +0800 From: Ye Bin To: , , CC: , , Ye Bin Subject: [PATCH -next v2 4/6] ext4: avoid to re-read mmp check data get from page cache Date: Sat, 11 Sep 2021 17:00:57 +0800 Message-ID: <20210911090059.1876456-5-yebin10@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210911090059.1876456-1-yebin10@huawei.com> References: <20210911090059.1876456-1-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: dggems706-chm.china.huawei.com (10.3.19.183) To dggeme754-chm.china.huawei.com (10.3.19.100) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org As call read_mmp_block pass bh_check which value is NULL, then call sb_getblk to get buffer_head. But mmp_block's buffer_head is already exist which also is uptodate. Lead to compare the same data. Signed-off-by: Ye Bin --- fs/ext4/mmp.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c index 4433fe7e9e86..007bde3c12b8 100644 --- a/fs/ext4/mmp.c +++ b/fs/ext4/mmp.c @@ -213,10 +213,7 @@ static int kmmpd(void *data) * we need to check if the MMP block is as we write it. */ if (jiffies - last_check_time > mmp_check_interval * HZ) { - struct buffer_head *bh_check = NULL; - struct mmp_struct *mmp_check; - - retval = read_mmp_block(sb, &bh_check, mmp_block); + retval = read_mmp_block(sb, &bh, mmp_block); if (retval) { ext4_error_err(sb, -retval, "error reading MMP data: %d", @@ -224,20 +221,18 @@ static int kmmpd(void *data) goto wait_to_exit; } - mmp_check = (struct mmp_struct *)(bh_check->b_data); - if (seq != mmp_check->mmp_seq || - memcmp(nodename, mmp_check->mmp_nodename, - sizeof(mmp->mmp_nodename))) { - dump_mmp_msg(sb, mmp_check, + mmp = (struct mmp_struct *)(bh->b_data); + if (seq != le32_to_cpu(mmp->mmp_seq) || + memcmp(nodename, mmp->mmp_nodename, + sizeof(nodename))) { + dump_mmp_msg(sb, mmp, "Error while updating MMP info. " "The filesystem seems to have been" " multiply mounted."); ext4_error_err(sb, EBUSY, "abort"); - put_bh(bh_check); retval = -EBUSY; goto wait_to_exit; } - put_bh(bh_check); last_check_time = jiffies; } -- 2.31.1