Re: [Qemu-devel] [PATCH v4 09/11] block: Accept node-name for drive-mirror

[Max Reitz]

On 02.08.2016 18:19, Kevin Wolf wrote:
> Am 18.07.2016 um 16:30 hat Max Reitz geschrieben:
>> On 14.07.2016 15:28, Kevin Wolf wrote:
>>> In order to remove the necessity to use BlockBackend names in the
>>> external API, we want to allow node-names everywhere. This converts
>>> drive-mirror to accept a node-name without lifting the restriction that
>>> we're operating at a root node.
>>>
>>> In case of an invalid device name, the command returns the GenericError
>>> error class now instead of DeviceNotFound, because this is what
>>> qmp_get_root_bs() returns.
>>>
>>> Signed-off-by: Kevin Wolf <address@hidden>
> 
>>> -    aio_context = blk_get_aio_context(blk);
>>> +    aio_context = bdrv_get_aio_context(bs);
>>>      aio_context_acquire(aio_context);
>>>  
>>> -    if (!blk_is_available(blk)) {
>>> -        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
>>> -        goto out;
>>> -    }
>>> -    bs = blk_bs(blk);
>>>      if (!has_mode) {
>>>          mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
>>>      }
>>
>> After this, bs->drv may be used. So I think we should keep a
>> bdrv_is_inserted() or bs->drv check here.
> 
> Do BDSes with bs->drv == NULL still happen normally, i.e. other than in
> cases where a driver gives up on a broken image? If not, maybe doing
> that check in qmp_get_root_bs() would be best.

Well, while corrupt qcow2 images aren't strictly normal, it can happen
and I don't think qemu should crash if one is encountered.

Max

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