From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:26474 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752453AbdK2Bsx (ORCPT ); Tue, 28 Nov 2017 20:48:53 -0500 Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id vAT1mqpl001083 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Wed, 29 Nov 2017 01:48:52 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id vAT1mqYu032313 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Wed, 29 Nov 2017 01:48:52 GMT Received: from abhmp0002.oracle.com (abhmp0002.oracle.com [141.146.116.8]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id vAT1mpxQ025458 for ; Wed, 29 Nov 2017 01:48:52 GMT Date: Tue, 28 Nov 2017 17:48:44 -0800 From: "Darrick J. Wong" Subject: [PATCH] xfsdocs: clarify log item header structure Message-ID: <20171129014844.GE21412@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: xfs From: Darrick J. Wong Make it more explicit that each log item has to start with a type code and size, except for transaction headers. Signed-off-by: Darrick J. Wong --- .../journaling_log.asciidoc | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/design/XFS_Filesystem_Structure/journaling_log.asciidoc b/design/XFS_Filesystem_Structure/journaling_log.asciidoc index 0aec036..6109458 100644 --- a/design/XFS_Filesystem_Structure/journaling_log.asciidoc +++ b/design/XFS_Filesystem_Structure/journaling_log.asciidoc @@ -217,6 +217,18 @@ magic number to distinguish themselves. Buffer data items only appear after | +XFS_LI_BUD+ | 0x1245 | xref:BUD_Log_Item[File Block Mapping Update Done] |===== +Note that all log items (except for transaction headers) MUST start with +the following header structure. The type and size fields are baked into +each log item header, but there is not a separately defined header. + +[source, c] +---- +struct xfs_log_item { + __uint16_t magic; + __uint16_t size; +}; +---- + [[Log_Transaction_Headers]] === Transaction Headers