From patchwork Sat Sep 11 09:00:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "yebin (H)" X-Patchwork-Id: 1526696 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4H660Y5Nbqz9sXk for ; Sat, 11 Sep 2021 18:51:09 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235458AbhIKIwP (ORCPT ); Sat, 11 Sep 2021 04:52:15 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:9419 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235402AbhIKIwO (ORCPT ); Sat, 11 Sep 2021 04:52:14 -0400 Received: from dggeme754-chm.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4H65vK4Tmlz8ySD; Sat, 11 Sep 2021 16:46:37 +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 16:51:00 +0800 From: Ye Bin To: , , CC: , , Ye Bin Subject: [PATCH -next v2 1/6] ext4: init seq with random value in kmmpd Date: Sat, 11 Sep 2021 17:00:54 +0800 Message-ID: <20210911090059.1876456-2-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 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 If two host has the same nodename, and seq start from 0, May cause the detection mechanism to fail. So init seq with random value to accelerate conflict detection. Signed-off-by: Ye Bin --- fs/ext4/mmp.c | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c index cebea4270817..12af6dc8457b 100644 --- a/fs/ext4/mmp.c +++ b/fs/ext4/mmp.c @@ -122,6 +122,21 @@ void __dump_mmp_msg(struct super_block *sb, struct mmp_struct *mmp, (int)sizeof(mmp->mmp_bdevname), mmp->mmp_bdevname); } +/* + * Get a random new sequence number but make sure it is not greater than + * EXT4_MMP_SEQ_MAX. + */ +static unsigned int mmp_new_seq(void) +{ + u32 new_seq; + + do { + new_seq = prandom_u32(); + } while (new_seq > EXT4_MMP_SEQ_MAX); + + return new_seq; +} + /* * kmmpd will update the MMP sequence every s_mmp_update_interval seconds */ @@ -132,7 +147,7 @@ static int kmmpd(void *data) struct buffer_head *bh = EXT4_SB(sb)->s_mmp_bh; struct mmp_struct *mmp; ext4_fsblk_t mmp_block; - u32 seq = 0; + u32 seq = mmp_new_seq(); unsigned long failed_writes = 0; int mmp_update_interval = le16_to_cpu(es->s_mmp_update_interval); unsigned mmp_check_interval; @@ -258,21 +273,6 @@ void ext4_stop_mmpd(struct ext4_sb_info *sbi) } } -/* - * Get a random new sequence number but make sure it is not greater than - * EXT4_MMP_SEQ_MAX. - */ -static unsigned int mmp_new_seq(void) -{ - u32 new_seq; - - do { - new_seq = prandom_u32(); - } while (new_seq > EXT4_MMP_SEQ_MAX); - - return new_seq; -} - /* * Protect the filesystem from being mounted more than once. */