From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752501Ab1HDHVw (ORCPT ); Thu, 4 Aug 2011 03:21:52 -0400 Received: from acsinet15.oracle.com ([141.146.126.227]:27008 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751769Ab1HDHVr (ORCPT ); Thu, 4 Aug 2011 03:21:47 -0400 Message-ID: <4E3A486D.7060506@oracle.com> Date: Thu, 04 Aug 2011 15:21:17 +0800 From: Joe Jin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:5.0) Gecko/20110707 Thunderbird/5.0 MIME-Version: 1.0 To: Daniel Stodden , Jens Axboe , Konrad Rzeszutek Wilk , Annie Li , Ian Campbell , Kurt C Hackel CC: Greg Marsden , "xen-devel@lists.xensource.com" , "linux-kernel@vger.kernel.org" , Joe Jin Subject: [PATCH -v3 0/3] xen-blkback: refactor vbd remove/disconnect. Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Source-IP: rtcsinet21.oracle.com [66.248.204.29] X-CT-RefId: str=0001.0A090202.4E3A4885.0088,ss=1,re=0.000,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patchset is a backport and original patch author is Daniel Stodden: http://xenbits.xen.org/hg/XCP/linux-2.6.32.pq.hg/file/tip/CA-7672-blkback-shutdown.patch Initial issue: When we do block device attach/detach test with below steps, umount hang in guest and the guest unable to shutdown: 1. start guest with the latest kernel. 2. attach new block device by xm block-attach in Dom0 3. mount new disk in guest 4. execute xm block-detach to detach the block device in dom0 until timeout 5. try to unmount the disk in guest, umount hung. at here, any IOs to the device will hang. Root cause: This caused by 'xm block-detach' in Dom0 set backend device's state to 'XenbusStateClosing', frontend received the notification and blkfront_closing() be called, at the moment, the disk still using by guest, so frontend refused to close. In the blkfront_closing(), frontend send a notification to backend said that the its state switched to 'Closing', when backend got the event, it will disconnect from real device, at here any IO request will be stuck, even tried to release the disk by umount. So this may fix either frontend or backend, I have send a fix for frontend: https://lkml.org/lkml/2011/7/8/159 Ian think we should fix it from backend and he pointed out Daniel Stodden have submitted a patch(see above link) for xen-blkback, I tried it and it works well. Changes: v3: - Unregister the device when backend state switch to XenbusStateClosed. v2: - Reformat code style. - Per Knoard suggestions, change some int defines to bool. drivers/block/xen-blkback/blkback.c | 10 +-- drivers/block/xen-blkback/common.h | 5 + drivers/block/xen-blkback/xenbus.c | 206 +++++++++++++++++++++++++++++++++++++++++++++++++++++++------- 3 files changed, 195 insertions(+), 26 deletions(-)