Re: qemu : rbd block driver internal snapshot and vm_stop is hanging forever

[Alexandre DERUMIER <aderumier@odiso.com>]

Also, 

this occur only with rbd_cache=false or qemu drive cache=none.


If I use rbd_cache=true or qemu drive cache=writeback, I don't have this bug.


----- Mail original -----
De: "aderumier" <aderumier@odiso.com>
À: "ceph-devel" <ceph-devel@vger.kernel.org>, "qemu-devel" <qemu-devel@nongnu.org>
Envoyé: Lundi 9 Novembre 2015 04:23:10
Objet: Re: qemu : rbd block driver internal snapshot and vm_stop is hanging forever

Some other infos: 

I can reproduce it too with manual snapshot with rbd command 


#rbd --image myrbdvolume snap create --snap snap1 

qemu monitor: 

#stop 


This is with ceph hammer 0.94.5. 


in qemu vm_stop, the only thing related to block driver are 

bdrv_drain_all(); 
ret = bdrv_flush_all(); 


----- Mail original ----- 
De: "aderumier" <aderumier@odiso.com> 
À: "ceph-devel" <ceph-devel@vger.kernel.org>, "qemu-devel" <qemu-devel@nongnu.org> 
Envoyé: Lundi 9 Novembre 2015 04:10:45 
Objet: qemu : rbd block driver internal snapshot and vm_stop is hanging forever 

Hi, 

with qemu (2.4.1), if I do an internal snapshot of an rbd device, 
then I pause the vm with vm_stop, 

the qemu process is hanging forever 


monitor commands to reproduce: 


# snapshot_blkdev_internal drive-virtio0 yoursnapname 
# stop 




I don't see this with qcow2 or sheepdog block driver for example. 


Regards, 

Alexandre 
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