From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH 0/2] splice: i_mutex vs splice write deadlock V2
Date: Wed, 10 Aug 2011 06:19:21 -0400
Message-ID: <20110810101921.GD27114@infradead.org>
References: <1312785927-10662-1-git-send-email-david@fromorbit.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: xfs@oss.sgi.com, linux-fsdevel@vger.kernel.org, mfasheh@suse.com,
	jlbec@evilplan.org
To: Dave Chinner <david@fromorbit.com>
Return-path: <linux-fsdevel-owner@vger.kernel.org>
Received: from 173-166-109-252-newengland.hfc.comcastbusiness.net ([173.166.109.252]:58180
	"EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK)
	by vger.kernel.org with ESMTP id S1751144Ab1HJKTY (ORCPT
	<rfc822;linux-fsdevel@vger.kernel.org>);
	Wed, 10 Aug 2011 06:19:24 -0400
Content-Disposition: inline
In-Reply-To: <1312785927-10662-1-git-send-email-david@fromorbit.com>
Sender: linux-fsdevel-owner@vger.kernel.org
List-ID: <linux-fsdevel.vger.kernel.org>

On Mon, Aug 08, 2011 at 04:45:25PM +1000, Dave Chinner wrote:
> generic_file_splice_write() takes the inode->i_mutex after the
> filesystem has taken whatever locks it needs to ensure sanity.
> however, this typically violates the locking order of filesystems
> with their own locks in that the order is usually i_mutex ->
> filesystem lock.
> 
> XFS is such a case, and generic_file_splice_write() is generating
> lockdep warnings because of lock inversions between the
> inode->i_mutex and the XFS_I(inode)->i_iolock. There is also a
> reported case of fio causing a deadlock when it mixes IO types
> (e.g. splice vs direct IO).

Another case is ocfs2, which looks like a perfect candidate to be
converted over to your infrastructure.