From: "Aneesh Kumar K.V" Subject: Re: RFC PATCH: ext4 no journal corruption with locale-gen Date: Fri, 10 Jul 2009 12:58:41 +0530 Message-ID: <20090710072841.GB19408@skywalker> References: <6601abe90906171148w1431258fvd0afa105cda9b77b@mail.gmail.com> <20090617234604.GF7867@mit.edu> <6601abe90906220942se70fb70w5481e178f1525dd8@mail.gmail.com> <20090701183130.GA31235@skywalker> <20090706034144.GB31532@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Theodore Tso , Curt Wohlgemuth , ext4 development To: Xiang Wang Return-path: Received: from e23smtp02.au.ibm.com ([202.81.31.144]:52437 "EHLO e23smtp02.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750848AbZGJH2u (ORCPT ); Fri, 10 Jul 2009 03:28:50 -0400 Received: from d23relay02.au.ibm.com (d23relay02.au.ibm.com [202.81.31.244]) by e23smtp02.au.ibm.com (8.13.1/8.13.1) with ESMTP id n6A7Qt6C023172 for ; Fri, 10 Jul 2009 17:26:55 +1000 Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay02.au.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n6A7SmFF1269834 for ; Fri, 10 Jul 2009 17:28:48 +1000 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n6A7SmlH017153 for ; Fri, 10 Jul 2009 17:28:48 +1000 Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Jul 09, 2009 at 11:30:58AM -0700, Xiang Wang wrote: > When working on the patch of adding the data=nojournal mount option, > I start to wonder whether this mount option is actually needed. > > When we mount a filesystem that was mkfs'ed with journal, using the > "noload" mount option > can help specify we do not load the journal. > > When we mount a filesystem that was mkfs'ed without journal, we simply > go into the > nojournal mode. > > That said, I do not really feel this data=nojournal option is necessary. > But I am still working on the patch to print appropriate messages when > people mount a filesystem > created without a journal but explicitly specify the "data=" option. > Any comments? > Now that I look at commit 0390131ba84fd3f726f9e24fc4553828125700bb if i understood correctly, that should always force a no journal mount to data=writeback ? I tested it as below mkfs.ext4 -O ^has_journal /home/opensource/images/ext3.img sudo mount -o loop /home/opensource/images/ext3.img /mnt/ [master@linux-2.6]$ cat /proc/mounts | grep mnt /dev/loop0 /mnt ext4 rw,relatime,barrier=1,data=writeback 0 0 So what we really need is to update ext4_should_writeback_data not to return 0 when we don't have a journal. Ted already have a patch in the patch queue that does the same. I guess that patch should get everything working fine. So if mke2fs have created a journal to run in no journal mode one can say -o noload. I guess that is more or less what we wanted. -aneesh