[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Re: xen-blkfront: Don't send closing notification to backend in blkfront_closing()
Konrad, Thanks for the reply, see comments in lines. On 07/09/11 00:04, Konrad Rzeszutek Wilk wrote: > 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? You are right and sorry for confusing. > > 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 <Domain> <DevId> [-f|--force] > The error caused by xm block-detach timeout to waiting the dev's state switch to Closed. > Destroy a domain's virtual block device. > [root@tst009 ~]# xm block-detach 6 51712 -f > With "--force", it always success but frontend did not disconnected if device opened by someone. > >> 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? This caused by backend kthread stopped, any IO request to the real device will hang, that is the patch intend to resolving. Thanks, Joe >> >> 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 <joe.jin@xxxxxxxxxx> >> Signed-off-by: Annie Li <annie.li@xxxxxxxxxx> >> --- >> 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); _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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