From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shaohua Li Subject: Re: [PATCH V3 1/2] RAID1: a new I/O barrier implementation to remove resync window Date: Tue, 28 Feb 2017 11:42:32 -0800 Message-ID: <20170228194232.ubkw6s3bxnl6nfyt@kernel.org> References: <20170220070430.4mca7clpaw7kpj4j@kernel.org> <7178ADEA-6263-4FB0-95A5-96E5F71A9740@suse.de> <878tp0s7w8.fsf@notabene.neil.brown.name> <20170221174542.rer73ywil3oq26gj@kernel.org> <488f88e0-8111-a320-3abb-c6e6611a957e@suse.de> <20170223173418.qrgjpj6utgceg5f4@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: =?utf-8?B?546L6YeR5rWm?= Cc: Coly Li , NeilBrown , linux-raid , Shaohua Li , Johannes Thumshirn , Guoqing Jiang List-Id: linux-raid.ids On Fri, Feb 24, 2017 at 11:19:05AM +0100, 王金浦 wrote: > Hi Coly, Hi Shaohua, > > > > > > Hi Shaohua, > > > > I try to catch up with you, let me try to follow your mind by the > > split-in-while-loop condition (this is my new I/O barrier patch). I > > assume the original BIO is a write bio, and original bio is split and > > handled in a while loop in raid1_make_request(). > > It's still possible for read bio. We hit a deadlock in the past. > See https://patchwork.kernel.org/patch/9498949/ > > Also: > http://www.spinics.net/lists/raid/msg52792.html Thanks Jinpu. So this is for the read side, where we don't have plug stuff. Yep, that finally makes sense. It's my fault I didn't look at the read side code carefully. Looks we need the patch Neil suggested. Thanks, Shaohua