Re: [Qemu-block] [PATCH] proto: add 'shift' extension.

[Denis V. Lunev]

On 09/28/2016 11:34 AM, Kevin Wolf wrote:
> Am 27.09.2016 um 20:59 hat Denis V. Lunev geschrieben:
>> On 09/27/2016 08:04 PM, Paolo Bonzini wrote:
>>> On 27/09/2016 15:28, Denis V. Lunev wrote:
>>>> On 09/27/2016 03:07 PM, Paolo Bonzini wrote:
>>>>> ----- Original Message -----
>>>>>> From: "Denis V. Lunev" <address@hidden>
>>>>>> To: "Paolo Bonzini" <address@hidden>
>>>>>> Cc: "Vladimir Sementsov-Ogievskiy" <address@hidden>, address@hidden, 
>>>>>> address@hidden,
>>>>>> address@hidden, address@hidden, address@hidden, address@hidden, 
>>>>>> address@hidden,
>>>>>> address@hidden
>>>>>> Sent: Tuesday, September 27, 2016 12:25:54 PM
>>>>>> Subject: Re: [PATCH] proto: add 'shift' extension.
>>>>>>
>>>>>> On 09/27/2016 01:15 PM, Paolo Bonzini wrote:
>>>>>>>> We could go in a different direction and export flag
>>>>>>>> 'has_zero_init' which will report that the storage is
>>>>>>>> initialized with all zeroes at the moment. In this
>>>>>>>> case mirroring code will not fall into this
>>>>>>>> branch.
>>>>>>> Why don't you add the zero_init flag to QEMU's NBD driver instead?
>>>>>> for all cases without knowing real backend on the server side?
>>>>>> I think this would be wrong.
>>>>> Add it to the command line, and leave it to libvirt or the user to
>>>>> pass "-drive file.driver=nbd,...,file.zero-init=on".
>>>> I have started with something very similar for 'drive-mirror' command.
>>>> We have added additional flag for this to improve migration speed
>>>> and this was rejected.
>>> You can add it through the filename path too, through a URI option
>>> "nbd://...?zero-init=on".
>>>
>>> Paolo
>> ha, cool idea! Thanks!
> What's the advantage of writing "?zero-init=on" instead of
> ",zero-init=on"? Doesn't it only add more string parsing code for no
> benefit?
>
> Kevin
Here I appreciate the idea to pass command line options in the
target file name. Will it be performed via comma or '?' - there
is no difference for us. We will check and use what is already
implemented.

The most important for us is an approach.

Den