From: Ted Ts'o Subject: Re: [PATCH 1/2] libext2fs: add metadata checksum and snapshot feature flags Date: Fri, 16 Sep 2011 10:28:25 -0400 Message-ID: <20110916142825.GB6342@thunk.org> References: <1316127052-1890-1-git-send-email-tytso@mit.edu> <1316127052-1890-2-git-send-email-tytso@mit.edu> <20110915231127.GK28181@thunk.org> <14955E98-C987-40D6-A881-5D40077C2FB2@dilger.ca> <20110915234131.GL28181@thunk.org> <20110916010604.GM28181@thunk.org> <036188D0-DA3B-4DD1-A097-F0B6AC4B4BB4@dilger.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Ext4 Developers List , "Darrick J. Wong" , Amir Goldstein To: Andreas Dilger Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:60067 "EHLO test.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753017Ab1IPO2a (ORCPT ); Fri, 16 Sep 2011 10:28:30 -0400 Content-Disposition: inline In-Reply-To: <036188D0-DA3B-4DD1-A097-F0B6AC4B4BB4@dilger.ca> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Sep 15, 2011 at 09:57:33PM -0600, Andreas Dilger wrote: > True, but at the same time is there a reason _not_ to put the checksum > at the end? For the superblock in particular it seems easy to do and > simplifies the code either way. For the superblock, OK. I'll buy that and I'll make the change so that tail end of the superblock looks like this: __u32 s_overhead_blocks; /* overhead blocks/clusters in fs */ __u32 s_reserved[108]; /* Padding to the end of the block */ __u32 s_checksum; /* crc32c(superblock) */ }; - Ted