Date: Mon, 30 Aug 2010 15:08:35 -0400
From: Mike Snitzer <snitzer@redhat.com>
To: Tejun Heo <tj@kernel.org>
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
Subject: Re: [PATCH 4/5] dm: implement REQ_FLUSH/FUA support for
 request-based dm
Message-ID: <20100830190835.GA8458@redhat.com>
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 <20100830132836.GB5283@redhat.com>
 <4C7BB932.1070405@kernel.org>
 <4C7BC942.7070703@kernel.org>
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On Mon, Aug 30 2010 at 11:07am -0400,
Tejun Heo <tj@kernel.org> 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 <snitzer@redhat.com>
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