[Qemu-devel] [RFC] block: Is name of BlockBackend deprecated with -blockdev parameter?

[Anton Kuchin]

Hello,

I'm trying to switch from -drive parameter to -blockdev + -device and 
having problems. Looks like with this option I have no way to set the 
name of  created BlockBackend, but some QMP and HMP commands are trying 
to find blk with blk_by_name() and fail to locate my device (e.g. 
hmp_commit, qmp_x_bloc_latency_histogram_set ...). Was it intentional 
and BB names are going to be deprecated?

This also seems to be a the case for all block devices hotplugged with 
QMP as they use the same code path.

As far as I understand all named backends are stored in 
monitor_block_backends list, but I can't get what is the point of having 
this list, and why parse_drive() function doesn't call monitor_add_blk() 
like blockdev_init() does with -drive option. Can someone give me a hint 
on this?

I also noticed that some commands fallback to search by qdev_id or 
BDS->node_name,  but at the creation time (both in bdrv_assing_node_name 
and monitor_add_blk) it is already checked that names are unique across 
these namespaces so may be it would be useful to introduce generic 
search function?

Thanks,
Anton