Comment 11 for bug 1746630

Revision history for this message
In , Peter (peter-redhat-bugs) wrote :

(In reply to Pei Zhang from comment #8)
> Try to reproduce it via libvirt.

[...]

> 2. disconnect with the NFS storage server.
> # iptables -A OUTPUT -d $IP -p tcp --dport 2049 -j DROP

[...]

> 3. on terminal 1, check IO throughttling with the image.
> # virsh domblklist r72
> Target Source
> ------------------------------------------------
> hda -
> vda /tmp/zp/r7.2.img
>
> # virsh blkdeviotune r72 vda

[...]

> 5. change to terminal 3. check block stat info, it will hang for a few
> seconds, then it will report an error.
> # virsh domblkstat r72
> (hang a few seconds)
> error: Timed out during operation: cannot acquire state change lock (held by
> remoteDispatchDomainGetBlockIoTune)

You have to call 'virsh domstats' here and request all, or at least "--block" at the point where the above API is returning failures. That should block the daemon. Listing guests and/or operations on the single guest should then block too.