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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A4FDC433F5 for ; Tue, 19 Oct 2021 09:10:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 362C960FED for ; Tue, 19 Oct 2021 09:10:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234918AbhJSJMm (ORCPT ); Tue, 19 Oct 2021 05:12:42 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:38218 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234927AbhJSJMi (ORCPT ); Tue, 19 Oct 2021 05:12:38 -0400 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id B4B04219CB; Tue, 19 Oct 2021 09:10:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1634634624; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Gt6nuIzfE5vuSZe4ZA9CcRAzQz3OFqf/MbzOSu8nXv0=; b=jrGdc/z/gp7YCYVnsCW8LLfsGXkRBSwXLscwgzo6H16xoXV+RaQcHOhZLOHexwm9jtcDRf dXPj1/JD4xoJIbeE7saOkQJcJ1JVh0PUj72xiapSIT7WuJk4Mo+M2+ivn4xcGnoqcIaHLo iGO2Qm+X2dhsfaway/ZRRzzQEOY/oEo= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1634634624; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Gt6nuIzfE5vuSZe4ZA9CcRAzQz3OFqf/MbzOSu8nXv0=; b=6ZxVnHZ7i/taV0GT5pIwEfjBw5Nrtiy57ej5KXxqZRXzO6WPZ+0vUgIgDSs90JTBPPmn/M pQIvLkxaZP4cSxDw== Received: from quack2.suse.cz (unknown [10.100.200.198]) by relay2.suse.de (Postfix) with ESMTP id 76F6CA3B81; Tue, 19 Oct 2021 09:10:24 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 56D1A1E0BE5; Tue, 19 Oct 2021 11:10:24 +0200 (CEST) Date: Tue, 19 Oct 2021 11:10:24 +0200 From: Jan Kara To: Ye Bin Cc: tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, jack@suse.cz Subject: Re: [PATCH -next v3 5/5] ext4: avoid to re-read mmp check data get from page cache Message-ID: <20211019091024.GC3255@quack2.suse.cz> References: <20211019064959.625557-1-yebin10@huawei.com> <20211019064959.625557-6-yebin10@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211019064959.625557-6-yebin10@huawei.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Tue 19-10-21 14:49:59, Ye Bin wrote: > 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 This patch needs to go earlier in the series - just after patch 2. Otherwise the read_mmp_block() cleanup is not correct. Otherwise it looks good, just some language corrections: ext4: remove useless bh_check variable Since we initialize 'bh_check' to NULL and pass it to read_mmp_block(), that function will just call sb_getblk() which will just return the buffer_head we have in 'bh'. So just remove the pointless 'bh_check' variable and use 'bh' directly. With this fixed feel free to add: Reviewed-by: Jan Kara Honza > --- > 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 61c765c249b9..8018f6fb6ac2 100644 > --- a/fs/ext4/mmp.c > +++ b/fs/ext4/mmp.c > @@ -186,10 +186,7 @@ static int kmmpd(void *data) > */ > diff = jiffies - last_update_time; > if (diff > mmp_check_interval * HZ) { > - struct buffer_head *bh_check = NULL; > - struct mmp_struct *mmp_check; > - > - retval = read_mmp_block(sb, bh_check); > + retval = read_mmp_block(sb, bh); > if (retval) { > ext4_error_err(sb, -retval, > "error reading MMP data: %d", > @@ -197,20 +194,18 @@ 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); > } > > /* > -- > 2.31.1 > -- Jan Kara SUSE Labs, CR