From: Theodore Tso Subject: Re: [PATCH 3/4]ext4: Fix possible recursive locking warning in EXT4_IOC_MOVE_EXT Date: Tue, 10 Nov 2009 16:55:33 -0500 Message-ID: <20091110215533.GE13262@mit.edu> References: <4AEA98C9.8030707@rs.jp.nec.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: ext4 development To: Akira Fujita Return-path: Received: from THUNK.ORG ([69.25.196.29]:55454 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758373AbZKJVz3 (ORCPT ); Tue, 10 Nov 2009 16:55:29 -0500 Content-Disposition: inline In-Reply-To: <4AEA98C9.8030707@rs.jp.nec.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Oct 30, 2009 at 04:42:01PM +0900, Akira Fujita wrote: > ext4: Fix possible recursive locking warning in EXT4_IOC_MOVE_EXT > > From: Akira Fujita Thanks, I've added this patch to the ext4 patch queue, but with the following updated commit description: ext4: Fix possible recursive locking warning in EXT4_IOC_MOVE_EXT From: Akira Fujita If CONFIG_PROVE_LOCKING is enabled, the double_down_write_data_sem() will trigger a false-positive warning of a recursive lock. Since we take i_data_sem for the two inodes ordered by their inode numbers, this isn't a problem. Use of down_write_nested() will notify the lock dependency checker machinery that there is no problem here. This problem was reported by Brian Rogers: http://marc.info/?l=linux-ext4&m=125115356928011&w=1 Reported-by: Brian Rogers Signed-off-by: Akira Fujita Signed-off-by: "Theodore Ts'o"