From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: [PATCH UPDATED 4/5] dm: implement REQ_FLUSH/FUA support for request-based dm Date: Wed, 1 Sep 2010 23:22:46 -0400 Message-ID: <20100902032246.GA31484@redhat.com> References: <4C7BB932.1070405@kernel.org> <4C7BD202.4040700@kernel.org> <20100830194731.GA10702@redhat.com> <4C7E36E8.2000705@kernel.org> <20100901152053.GA25644@redhat.com> <20100901170743.GB25644@redhat.com> <20100901185907.GA26411@redhat.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20100901185907.GA26411@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Tejun Heo Cc: dm-devel@redhat.com, Mikulas Patocka , Vivek Goyal List-Id: dm-devel.ids On Wed, Sep 01 2010 at 2:59pm -0400, Mike Snitzer wrote: > But we can meet in the middle. I've reordered the DM FLUSH+FUA patches > so that the more intrusive bio-based relaxed ordering patch is at the > very end. > > My hope was that the request-based deadlock I'm seeing would disappear > if that relaxed ordering patch wasn't applied. Unfortunately, I still > see the hang. Turns out I can reproduce the hang on a stock 2.6.36-rc3 (without _any_ FLUSH+FUA patches)! I'll try to pin-point the root cause but I think my test is somehow exposing a bug in my virt setup. So this hang is definitely starting to look like a red herring. Tejun, This news should clear the way for you to re-post your patches. I think it would be best if you reordered the DM patches like I did here in this series: http://people.redhat.com/msnitzer/patches/flush-fua/series In particular, the dm-relax-ordering-of-bio-based-flush-implementation patch should go at the end. I think it makes for a more logical evolution of the DM code. Thanks, Mike