From: Theodore Tso Subject: Re: RFC PATCH: ext4 no journal corruption with locale-gen Date: Sun, 5 Jul 2009 23:41:44 -0400 Message-ID: <20090706034144.GB31532@mit.edu> References: <6601abe90906171148w1431258fvd0afa105cda9b77b@mail.gmail.com> <20090617234604.GF7867@mit.edu> <6601abe90906220942se70fb70w5481e178f1525dd8@mail.gmail.com> <20090701183130.GA31235@skywalker> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Curt Wohlgemuth , ext4 development To: "Aneesh Kumar K.V" Return-path: Received: from thunk.org ([69.25.196.29]:58250 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752346AbZGFDlr (ORCPT ); Sun, 5 Jul 2009 23:41:47 -0400 Content-Disposition: inline In-Reply-To: <20090701183130.GA31235@skywalker> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Jul 02, 2009 at 12:01:30AM +0530, Aneesh Kumar K.V wrote: > > I looked at the patch in detail and I guess we should instead force > a data=writeback mode if the filesystem is created without a journal. > I am not sure what whould be the meaning of data=ordered/data=journal > without a journal. So if we find that file system doesn't have a journal > then either we should update the default mount option in the filesystem > to be of data=writeback. Here's a patch which takes your approach to solving the problem. What do you think? I haven't messed with dealing with the data= mount options in fs/ext4/super.c. That's important from a UI point of view, but we needed to fix ext4_jbd2.h since it was unconditionally returning 0 if there was no journal for all of the ext4_should_*_data() functions. I believe this should DTRT with the -o nobh mount option, but I'd appreciate another pair of eyes taking a look at this. - Ted commit 2a73eff8ba80095a871a6b402dfd24bc454e5bdc Author: Theodore Ts'o Date: Sun Jul 5 23:37:13 2009 -0400 ext4: fix no journal corruption with locale-gen If there is no journal, ext4_should_writeback_data() should return TRUE. This will fix ext4_set_aops() to set ext4_da_ops in the case of delayed allocation; otherwise ext4_journaled_aops gets used by default, which doesn't handle delayed allocation properly. The advantage of using ext4_should_writeback_data() approach is that it should handle nobh better as well. Thanks to Curt Wohlgemuth for investigating this problem, and Aneesh Kumar for suggesting this approach. Signed-off-by: "Theodore Ts'o" diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h index be2f426..f800134 100644 --- a/fs/ext4/ext4_jbd2.h +++ b/fs/ext4/ext4_jbd2.h @@ -282,7 +282,7 @@ static inline int ext4_should_order_data(struct inode *inode) static inline int ext4_should_writeback_data(struct inode *inode) { if (EXT4_JOURNAL(inode) == NULL) - return 0; + return 1; if (!S_ISREG(inode->i_mode)) return 0; if (EXT4_I(inode)->i_flags & EXT4_JOURNAL_DATA_FL)