From: Andreas Dilger Subject: Re: [PATCH 2/2] ext4: Automatically enable journal_async_commit on ext4 file systems Date: Sun, 06 Sep 2009 00:57:47 +0200 Message-ID: <20090905225747.GP4197@webber.adilger.int> References: <1252189963-23868-1-git-send-email-tytso@mit.edu> <1252189963-23868-2-git-send-email-tytso@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; CHARSET=US-ASCII Content-Transfer-Encoding: 7BIT Cc: Ext4 Developers List To: "Theodore Ts'o" Return-path: Received: from sca-es-mail-2.Sun.COM ([192.18.43.133]:60229 "EHLO sca-es-mail-2.sun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751896AbZIEW5t (ORCPT ); Sat, 5 Sep 2009 18:57:49 -0400 Received: from fe-sfbay-10.sun.com ([192.18.43.129]) by sca-es-mail-2.sun.com (8.13.7+Sun/8.12.9) with ESMTP id n85MvpIl004373 for ; Sat, 5 Sep 2009 15:57:51 -0700 (PDT) Content-disposition: inline Received: from conversion-daemon.fe-sfbay-10.sun.com by fe-sfbay-10.sun.com (Sun Java(tm) System Messaging Server 7u2-7.04 64bit (built Jul 2 2009)) id <0KPI00F00T3VAA00@fe-sfbay-10.sun.com> for linux-ext4@vger.kernel.org; Sat, 05 Sep 2009 15:57:51 -0700 (PDT) In-reply-to: <1252189963-23868-2-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sep 05, 2009 18:32 -0400, Theodore Ts'o wrote: > Now that we have cleaned up journal_async_commit, it's safe to enable > it all the time. But we only want to do so if ext4-specific INCOMPAT > features are enabled, since otherwise we will prevent the filesystem > from being mounted using ext3. So, the big question is what to do if not-the-last transaction in the journal has a bad block in it? This is fairly unlikely, and IMHO the harm of aborting journal replay too early is likely far outweighed by the benefit of not "recovering" garbage directly over the filesystem metadata. I had thought that you had rejected the e2fsck side of this patch for that reason, but maybe my memory is faulty... We still have some test images for bad journal checksums that you can have if you want. Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc.