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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6DC7FC433EF for ; Wed, 22 Dec 2021 22:08:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234122AbhLVWIe (ORCPT ); Wed, 22 Dec 2021 17:08:34 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:40148 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230063AbhLVWId (ORCPT ); Wed, 22 Dec 2021 17:08:33 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B8C10B81CFE for ; Wed, 22 Dec 2021 22:08:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7399DC36AE5; Wed, 22 Dec 2021 22:08:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1640210906; bh=pLXNVpLHl2Lz6gE62PZTOGS40oPaX6m/H41TSwbX6lg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=presPs1/jgBYQT/xZfoahLPCZReeDvIIZZ4DyADAc3V7yeJsMcEwHQfhdgLfdcfHC V5EAsOtCMKuPw5yAPymwLQK+ZCShf7UKjOS4k9RdKWNIDxW9ifdo3brDreK9fEniJd QGbRcTSOC+Cs1MV0zs1TLwMKfuLwr5DYaL94HP8pV1DMdq3i4M4fFFuCS55rXG5yi8 KpVzBLvCWhyqj+3dkT6w1bbubfv3CktVUPE0CBuYGH65KDUXKzjEffpl31btLB4q/Q epvVasVeBsxroxzYV5xkH3q/kqUNJbftpnYqQ+Nov1hcvzBJKs4BRw9GtSecUr0LgY nl+cP+xz2c18Q== Date: Wed, 22 Dec 2021 14:08:26 -0800 From: "Darrick J. Wong" To: xfs Cc: Wengang Wang Subject: Re: [PATCH] design: fix computation of buffer log item bitmap size Message-ID: <20211222220826.GD27664@magnolia> References: <20211110015820.GX24307@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211110015820.GX24307@magnolia> Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Tue, Nov 09, 2021 at 05:58:20PM -0800, Darrick J. Wong wrote: > From: Darrick J. Wong > > Wengang Wang was trying to work through a buffer log item by consulting > the ondisk format documentation, and was confused by the formula given > in section 14.3.14 regarding the size of blf_data_map, aka the dirty > bitmap for buffer log items. We noticed that the documentation doesn't > match what the kernel actually does, so let's fix this. > > Reported-by: Wengang Wang > Signed-off-by: Darrick J. Wong This is probably a bad time for this, but... ping? --D > --- > .../journaling_log.asciidoc | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/design/XFS_Filesystem_Structure/journaling_log.asciidoc b/design/XFS_Filesystem_Structure/journaling_log.asciidoc > index 1dba56e..894d3e5 100644 > --- a/design/XFS_Filesystem_Structure/journaling_log.asciidoc > +++ b/design/XFS_Filesystem_Structure/journaling_log.asciidoc > @@ -992,7 +992,7 @@ The size of +blf_data_map+, in 32-bit words. > This variable-sized array acts as a dirty bitmap for the logged buffer. Each > 1 bit represents a dirty region in the buffer, and each run of 1 bits > corresponds to a subsequent log item containing the new contents of the buffer > -area. Each bit represents +(blf_len * 512) / (blf_map_size * NBBY)+ bytes. > +area. Each bit represents +(blf_len * 512) / (blf_map_size * sizeof(unsigned int) * NBBY)+ bytes. > > [[Buffer_Data_Log_Item]] > === Buffer Data Log Item