Re: [libvirt] [PATCH 2/3] virsh: prevent destroying a in-used network for net-destroy

On 02/02/2015 09:08 AM, Lin Ma wrote: > * add --system flag for net-dumpxml to show information about the > attached interfaces of the virtual network. I don't like this extra flag - I think it is unnecessary. If we're going to more info to the status, then we can just always add it to the status. As to how it can be provided in the status XML (getting back to patch 1/3 which was using the netcf API in a way that I didn't like), better data can be gathered into a list in the network object as guests are created - this would be done in networkAllocateActualDevice() (and networkNotifyActualDevice()) at the points where connections is incremented for the network, and removed from the list in networkReleaseActualDevice() where connections is decremented. You'll notice that those functions get both the virDomainDefPtr and the virDomainNetDefPtr, so they have enough information to store the name of the domain as well as the namne of the interface. I recall a long time ago considering adding this information to the network XML, but I was dissuaded for some reason; unfortunately I don't remember why... > > * call virNetworkGetXMLDesc in cmdNetworkDestroy to get the live state > info to check whether the virtual network is in use. > > * add --force flag for net-destroy to forcibly destroy the virtual > network even if it's in use. As Michal points out (and I pointed out when you sent your previous patchset), this does change behavior that some scripts may be dependent on. I too like the increased safety, but am concerned about breaking functionality. In cases like this, I always like to hear the learned advice of Dan Berrange - Daniel, what do you say about changing the default behavior of virsh net-destroy? Safe enough?

> -=item B<net-dumpxml> I<network> [I<--inactive>] > +=item B<net-dumpxml> I<network> [I<--inactive>] [I<--system>] > > Output the virtual network information as an XML dump to stdout. > If I<--inactive> is specified, then physical functions are not > expanded into their associated virtual functions. > +If I<--system> is specified, then directly output the current > +live state corresponding to this network from system.