On Mon, Feb 15, 2010 at 4:39 PM, Stefan Berger <stefanb@us.ibm.com> wrote:
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 shutdown'ed 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