From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754095Ab1GHQEe (ORCPT ); Fri, 8 Jul 2011 12:04:34 -0400 Received: from acsinet15.oracle.com ([141.146.126.227]:21697 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752207Ab1GHQEc (ORCPT ); Fri, 8 Jul 2011 12:04:32 -0400 Date: Fri, 8 Jul 2011 12:04:14 -0400 From: Konrad Rzeszutek Wilk To: Joe Jin Cc: Daniel Stodden , Jens Axboe , annie.li@oracle.com, Jeremy Fitzhardinge , Ian Campbell , Kurt C Hackel , Greg Marsden , "xen-devel@lists.xensource.com" , "linux-kernel@vger.kernel.org" Subject: Re: xen-blkfront: Don't send closing notification to backend in blkfront_closing() Message-ID: <20110708160414.GA30120@dumpdata.com> References: <4E16AE55.50500@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E16AE55.50500@oracle.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: acsinet22.oracle.com [141.146.126.238] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090208.4E172A8C.0076:SCFMA922111,ss=1,re=-4.000,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 08, 2011 at 03:14:29PM +0800, Joe Jin wrote: > When we do block attach detach test with below steps, umount hang and the > guest unable to shutdown: > > 1. start guest with the latest kernel. > 2. attach new disk by xm-attach in Dom0 > 3. mount new disk in guest > 4. detach the disk by xm-detach in dom0 I think you mean xm block-detach and xm-attach? I tried with and without your patch and in both cases I get this in my guest: sh-4.1# mount /dev/xvda /test [ 385.949749] EXT3-fs: barriers not enabled [ 385.960173] kjournald starting. Commit interval 5 seconds [ 385.960418] EXT3-fs (xvda): using internal journal [ 385.960427] EXT3-fs (xvda): mounted filesystem with writeback data mode sh-4.1# [ 411.176887] vbd vbd-51712: 16 Device in use; refusing to close The commands on the other side (Dom0) were: [root@tst009 ~]# xm block-list 6 Vdev BE handle state evt-ch ring-ref BE-path 51712 0 0 4 12 770 /local/domain/0/backend/vbd/6/51712 [root@tst009 ~]# xm block-detach 6 51712 Error: Device 51712 (vbd) could not be disconnected. Usage: xm block-detach [-f|--force] Destroy a domain's virtual block device. [root@tst009 ~]# xm block-detach 6 51712 -f > 5. umount the partition/disk in guest, command hung. exactly at here, any > IO request to the partition/disk will hang. I get that with the patch and without it: sh-4.1# sh-4.1# [ 519.814048] block xvda: device/vbd/51712 was hot-unplugged, 1 stale handles sh-4.1# df -h Filesystem Size Used Avail Use% Mounted on none 490M 120K 490M 1% /dev none 490M 131M 359M 27% /lib/modules/3.0.0-rc6-00052-g3edce4b-dirty shm 10M 0 10M 0% /dev/shm var_tmp 10M 0 10M 0% /var/tmp /dev/xvda 20G 173M 19G 1% /test sh-4.1# umount /test Any ideas? > > Checking the code we found when xm-detach command set backend state to > Closing, will trigger blkback_changed() -> blkfront_closing() call. > At the moment, the disk still opened by guest, so frontend will refuse the > request, but in the blkfront_closing(), it send a notification to backend > said that the frontend 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. > > Per our test, below patch fix this issue. > > Signed-off-by: Joe Jin > Signed-off-by: Annie Li > --- > xen-blkfront.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c > index b536a9c..f6d8ac2 100644 > --- a/drivers/block/xen-blkfront.c > +++ b/drivers/block/xen-blkfront.c > @@ -1088,7 +1088,7 @@ blkfront_closing(struct blkfront_info *info) > if (bdev->bd_openers) { > xenbus_dev_error(xbdev, -EBUSY, > "Device in use; refusing to close"); > - xenbus_switch_state(xbdev, XenbusStateClosing); > + xbdev->state = XenbusStateClosing; > } else { > xlvbd_release_gendisk(info); > xenbus_frontend_closed(xbdev); > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/