From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: [PATCH 4/5] dm: implement REQ_FLUSH/FUA support for request-based dm Date: Mon, 30 Aug 2010 15:08:35 -0400 Message-ID: <20100830190835.GA8458@redhat.com> References: <1283162296-13650-1-git-send-email-tj@kernel.org> <1283162296-13650-5-git-send-email-tj@kernel.org> <20100830132836.GB5283@redhat.com> <4C7BB932.1070405@kernel.org> <4C7BC942.7070703@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: jaxboe@fusionio.com, k-ueda@ct.jp.nec.com, j-nomura@ce.jp.nec.com, jamie@shareable.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-raid@vger.kernel.org, hch@lst.de To: Tejun Heo Return-path: Content-Disposition: inline In-Reply-To: <4C7BC942.7070703@kernel.org> Sender: linux-raid-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Mon, Aug 30 2010 at 11:07am -0400, Tejun Heo wrote: > On 08/30/2010 03:59 PM, Tejun Heo wrote: > > Ah... that's probably from "if (!elv_queue_empty(q))" check below, > > flushes are on a separate queue but I forgot to update > > elv_queue_empty() to check the flush queue. elv_queue_empty() can > > return %true spuriously in which case the queue won't be plugged and > > restarted later leading to queue hang. I'll fix elv_queue_empty(). > > I think I was too quick to blame elv_queue_empty(). Can you please > test whether the following patch fixes the hang? It does, thanks! Tested-by: Mike Snitzer