Re: [Qemu-devel] [PATCH v2 2/2] blockjob: use blk_new_pinned in block_job_create

[Vladimir Sementsov-Ogievskiy]

05.06.2019 20:11, Kevin Wolf wrote:
> Am 05.06.2019 um 14:32 hat Vladimir Sementsov-Ogievskiy geschrieben:
>> child_role job already has .stay_at_node=true, so on bdrv_replace_node
>> operation these child are unchanged. Make block job blk behave in same
>> manner, to avoid inconsistent intermediate graph states and workarounds
>> like in mirror.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> 
> This feels dangerous. It does what you want it to do if the only graph
> change below the BlockBackend is the one in mirror_exit_common. But the
> user could also take a snapshot, or in the future hopefully insert a
> filter node, and you would then want the BlockBackend to move.
> 
> To be honest, even BdrvChildRole.stay_at_node is a bit of a hack. But at
> least it's only used for permissions and not for the actual data flow.
> 

Hmm. Than, may be just add a parameter to bdrv_replace_node, which parents
to ignore? Would it work?


-- 
Best regards,
Vladimir