Re: [libvirt] [PATCH] Fix macvtap device tear down problem on virsh destroy

On Mon, Feb 15, 2010 at 4:39 PM, Stefan Berger <stefanb(a)us.ibm.com&gt;

> This patch fixes the problem with the tear down of the macvtap device > when issuing a 'virsh destroy' by moving the tear down block past the > point of killing the Qemu process. It seems necessary to loop at least > once in the case of 'virsh destory' since the device seems to be busy > for a while after the Qemu process has been killed. This also still > properly tears down the macvtap device when the VM is 'virsh

> or halted from inside. I think it's fine to check just once, before replacing an existing macvtap interface with a new one, that the existing interface's fd can be opened, to avoid stomping on an interface owned by someone else. On shutdown, I think it's safe to assume that an interface whose name, macaddr and type matches is in fact the interface it created. I think it should just go ahead and delete it without again trying to open the fd. Otherwise we end up with such annoying races, e.g. if qemu hangs or takes a long time to shut down, you end up leaving the orphaned interfaces sitting around as well as the hung qemu process.

--Ed