From: Ted Ts'o Subject: Re: [PATCH v2 2/3] jbd2: Add extra parameter in start_this_handle() to control allocation flags. Date: Wed, 8 Jun 2011 10:10:06 -0400 Message-ID: <20110608141006.GG30037@thunk.org> References: <1306563416-4286-1-git-send-email-mkatiyar@gmail.com> <1306563657-4334-1-git-send-email-mkatiyar@gmail.com> <20110531112253.GD5614@quack.suse.cz> <20110531222720.GA3867@thunk.org> <20110602095424.GA5718@quack.suse.cz> <20110606032113.GC7180@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Manish Katiyar , linux-ext4@vger.kernel.org, mfasheh@suse.com, jlbec@evilplan.org To: Jan Kara Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:36283 "EHLO test.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754974Ab1FHOKJ (ORCPT ); Wed, 8 Jun 2011 10:10:09 -0400 Content-Disposition: inline In-Reply-To: <20110606032113.GC7180@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: Ping? - Ted On Sun, Jun 05, 2011 at 11:21:13PM -0400, Ted Ts'o wrote: > On Thu, Jun 02, 2011 at 11:54:24AM +0200, Jan Kara wrote: > > What happens is that direct reclaim sometimes does > > wait_on_page_writeback() (e.g. shrink_page_list()) or it explicitely waits > > for NR_WRITEBACK statistics to go below some threshold > > (throttle_vm_writeout()). And that is deadlockable if we hold i_mutex while > > doing this because we may need i_mutex to actually move the page from > > PageWriteback state... > > We don't actully call set_page_writeback() until right before we > submit the page for writeback. And we convert the unwritten extents > in a workqueue, which gets submitted after we call > end_page_writeback(). So I'm still not seeing a problem; sorry if I'm > being dense! > > - Ted > > > As I'm saying this, I've realized ext4 has this problem also with > > stable-pages patches because there we can wait for PageWriteback in > > grab_cache_page_write_begin() when we also hold i_mutex. So I think we'll > > have to come up with a way to convert unwritten extents without having to > > hold i_mutex. That's going to be interesting. > > > > Honza > > -- > > Jan Kara > > SUSE Labs, CR > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html