From: Josef Bacik <jbacik@redhat.com>
Subject: Re: Ordered mode rewrite patch
Date: Fri, 11 Apr 2008 14:42:58 -0400
Message-ID: <20080411184258.GA2757@unused.rdu.redhat.com>
References: <20080408121149.GB6901@duck.suse.cz>
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Cc: Nathan Grennan <jack@cygnusx-1.org>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	linux-ext4@vger.kernel.org
To: Jan Kara <jack@suse.cz>
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In-Reply-To: <20080408121149.GB6901@duck.suse.cz>
Sender: linux-ext4-owner@vger.kernel.org

On Tue, Apr 08, 2008 at 02:11:49PM +0200, Jan Kara wrote:
>   Hello,
> 
>   attached is a jumbo patch that reverses locking order of transaction
> start and page lock in ext3 and rewrites handling of ordered data mode in
> JBD and ext3. Note that the patch will break compilation of ext4 and OCFS2.
> The patch survives LTP run on my test machine so it shouldn't eat your data
> immediately but bugs are of course possible...
>   I'm very interested in any results (both positive and negative) you could
> get with it :). Thanks for testing it.
> 
> 									Honza
>

Hey Jan,

I just hit a problem with your patch.  In journal_destroy() we do a
iput(journal->j_inode) and then kfree the journal, so when the iput comes back
into journal_release_jbd_inode we are doing a use after free which in my case
resulted in a panic.  I was going to fix it but I figure since this is still in
transit you would have to just rewrite it so I'm not going to attach one, just
giving you a heads up.  Let me know if my explanation wasn't clear enough.
Thanks much,

Josef