[PATCH] qemu: Don't crash when getting targets for a multipath

[Peter Krempa]

On Thu, Mar 19, 2020 at 18:39:58 +0100, Michal Privoznik wrote:
> On 19. 3. 2020 17:43, Peter Krempa wrote:
> > On Thu, Mar 19, 2020 at 17:22:37 +0100, Michal Privoznik wrote:
> >> In one of my previous commits I've introduced code that creates
> >> all devices for given (possible) multipath target. But I've made
> >> a mistake there - the code accesses src->path without checking if
> >> the disk source is local. Note that the path is NULL if the
> >> source is not local.
> > 
> > Well next->path 'may' be NULL if it's not local, but in this case it is
> > local because NVMe disks are local, but they don't have the path.
> 
> Local as in virStorageSourceIsLocalStorage() == true. And for NVMe we
> return false exactly because src->path has to be NULL (it can't be set
> to any meaningfull path).

Yes. The meaning of virStorageSourceIsLocalStorage shifted after NVMe
disks were added.

> 
> How about this formulation:
> 
> Note that the path is NULL if the
> source is not local as viewed by
> virStorageSourceIsLocalStorage().

That is still misleading, because network disks can have non-null path.

I'd prefer:

'next->path' is NULL/doesn't make sense for VIR_STORAGE_TYPE_NVME