From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755734Ab2I0V1Q (ORCPT ); Thu, 27 Sep 2012 17:27:16 -0400 Received: from li9-11.members.linode.com ([67.18.176.11]:52770 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754850Ab2I0V1P (ORCPT ); Thu, 27 Sep 2012 17:27:15 -0400 Date: Thu, 27 Sep 2012 17:27:08 -0400 From: "Theodore Ts'o" To: Hugh Dickins Cc: Andrew Morton , Christoph Hellwig , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: next/mmotm: ext4 causes !rwsem_is_locked warnings Message-ID: <20120927212708.GA10044@thunk.org> Mail-Followup-To: Theodore Ts'o , Hugh Dickins , Andrew Morton , Christoph Hellwig , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 27, 2012 at 02:05:00PM -0700, Hugh Dickins wrote: > Hi Ted, > > mmotm (or next) now gives me lots of WARNING at fs/fs-writeback.c:1312 from > writeback_inodes_sb_nr(). That's WARN_ON(!rwsem_is_locked(&sb->s_umount)) > (some useful safety from hch) in writeback_inodes_sb_nr(). > > Your commit 40e684e5c597a98996cf4616e31fb2581ec82060 > "ext4: fix potential deadlock in ext4_nonda_switch()" needs more change > to fs/fs-writeback.c. I guess I'm the only one using a nearly full ext4. > > I am, of course, applying the patch at the bottom to my tree for now; > but I think you'd do better not to eliminate that check. Maybe add a > special wb_reason for your case, and skip rwsem check in that case. Yeah, we were just discussing this on another thread. I didn't think of the option of creating a new special wb_reason option, but that's a much better option than the other ones I had been considering, so I think I will give that a try. Thanks for the suggestion!! - Ted