Re: [Qemu-devel] [PATCH 1/5] block: Auto-generate node_names for each BDS entry

[Jeff Cody <jcody@redhat.com>]

On Fri, May 16, 2014 at 11:39:27AM +0200, Kevin Wolf wrote:
> Am 15.05.2014 um 20:41 hat Jeff Cody geschrieben:
> > The only thing I don't like about moving this further back in the
> > patch series is it makes the earlier patches untestable; I can't
> > easily test the usage of the node-names for various intermediate BDS
> > because they don't have node-names set.  So that means I'll just need
> > to rebase the patches prior to sending.
> 
> I don't quite follow. Can't you always manually assign node-names? This
> is how libvirt is supposed to use the interface.
>

How does libvirt assign node-names to all the backing images in a
qcow2 chain, for example?


> I'm not totally sure whether automatically generated node-names are
> a good idea, but I can see how they are useful with human monitor users
> which may not specify a node-name everywhere (I've used device_add
> without an ID often enough, only to find that I can't remove the device
> any more). We should just make sure that they are really only used by
> human users.
>

I don't understand.  What would be the downsides of having an
automatic guaranteed unique id assigned to each BDS?  And why
restrict that to human users only?

If you are worried about node-names potentially being undesired by the
user / management layer for some reason, how about this: we add a
drive option, to either enable or disable automatic node-name
generation for a particular drive?