From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8CB7DC282D7 for ; Wed, 30 Jan 2019 15:54:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CEA521473 for ; Wed, 30 Jan 2019 15:54:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="G71dg7fP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731494AbfA3PyN (ORCPT ); Wed, 30 Jan 2019 10:54:13 -0500 Received: from mail-it1-f181.google.com ([209.85.166.181]:56261 "EHLO mail-it1-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730879AbfA3PyM (ORCPT ); Wed, 30 Jan 2019 10:54:12 -0500 Received: by mail-it1-f181.google.com with SMTP id m62so10903927ith.5 for ; Wed, 30 Jan 2019 07:54:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=UFXl6eSt7YREHuSXVl+VGiJiGCCG/lipfkwNUV78+c0=; b=G71dg7fPN2FM6D5c2wd1HeUSkUy6tkDT1v2JDJG5Ga82gFxy3ZoQqDvZ04qScXPZwM ViF1ZrvyM72uB/gyGNlEePzCT+M7DRgZdMQRa2hzpeha6N1ccn65nmRMlTJqPc5Io086 DaLuAqxhT9AWMTvaxKcfwK21X3wbMkwe8I106Cx1GqEAxSVoHsCwq+SgP9Qx7A5q+pt4 3+w2sJ7N+/bxUx8a/vK4C5CuKsP+oX1b3Gl5mbFhS7c2nf34Oc/1QUVhpwcU/t2nP1W2 /e2ZDD9Uedhyp3+a5YjOs9+rDY3XiDLTz9jvcknnl36a+/9AAG5qVt5HZ88QDWmKvsGS 3eMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=UFXl6eSt7YREHuSXVl+VGiJiGCCG/lipfkwNUV78+c0=; b=d1da8oiqgoEhLS6u073dtdMKRSgqu5q5YgUeOQQQF12pw02JrNE1EBZew5m54q0dG/ l0khOKoNfbf1oWXEfzfZBIV/tujFfZShyXPLNbUt1JbOBJBRkRWi5voqHvF3r3oZ+6c1 7/np3RAywPbVbWqQAYVNilJhatyWui6bSeOyJW8HC39LrA/LoFOPGNJaX+RxhayyLzq8 wsJNSrDPm3nBFVDq0U+iBFTrI9Nult0GEOlP+tbYymb6uIYxdFsoSzHHtTb8NxYL7i23 o3bWOUVN4BH/DV8aSqp5A8AxtVu18FCPTQfQgDuOvcK/Pu8X5pA9nLsjACQntRWrbyMU eSLA== X-Gm-Message-State: AHQUAubh7f1W5FTK66Ve5ZuZPSUHkg0vCngTH8C8+l7y+06x7PM+EZOP /Eom+4NyRhMG3jjEpT3g/puPP7jPGHM= X-Google-Smtp-Source: AHgI3IY2oQrIgeRKkOH5l1gUeyCviox90H926k55DRaeK3pXxE6nNaSv4CjJAsTBLgEMDSrcwhsx3Q== X-Received: by 2002:a24:be0b:: with SMTP id i11mr6503334itf.0.1548863651077; Wed, 30 Jan 2019 07:54:11 -0800 (PST) Received: from [192.168.1.158] ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id h14sm800356ior.41.2019.01.30.07.54.09 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 30 Jan 2019 07:54:10 -0800 (PST) Subject: Re: [PATCH] blk-mq: fix a hung issue when fsync To: Jianchao Wang Cc: m19@florianstecker.de, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <1548838916-25051-1-git-send-email-jianchao.w.wang@oracle.com> From: Jens Axboe Message-ID: <319fffef-2fa8-afff-8f93-1ce8fd721581@kernel.dk> Date: Wed, 30 Jan 2019 08:54:09 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <1548838916-25051-1-git-send-email-jianchao.w.wang@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/30/19 2:01 AM, Jianchao Wang wrote: > Florian reported a io hung issue when fsync(). It should be > triggered by following race condition. > > data + post flush a flush > > blk_flush_complete_seq > case REQ_FSEQ_DATA > blk_flush_queue_rq > issued to driver blk_mq_dispatch_rq_list > try to issue a flush req > failed due to NON-NCQ command > .queue_rq return BLK_STS_DEV_RESOURCE > > request completion > req->end_io // doesn't check RESTART > mq_flush_data_end_io > case REQ_FSEQ_POSTFLUSH > blk_kick_flush > do nothing because previous flush > has not been completed > blk_mq_run_hw_queue > insert rq to hctx->dispatch > due to RESTART is still set, do nothing > > To fix this, replace the blk_mq_run_hw_queue in mq_flush_data_end_io > with blk_mq_sched_restart to check and clear the RESTART flag. Applied, thanks. -- Jens Axboe