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Date: Wed, 11 Dec 2013 11:52:28 +0800
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Subject: Re: [Qemu-devel] [PATCH V4 4/7] qmp: Allow to change password on
 names block driver states.
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To: Luiz Capitulino <lcapitulino@redhat.com>, Kevin Wolf <kwolf@redhat.com>
Cc: =?UTF-8?B?QmVub8OudCBDYW5ldA==?= <benoit@irqsave.net>, jcody@redhat.com, armbru@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com

On 2013=E5=B9=B412=E6=9C=8810=E6=97=A5 23:16, Luiz Capitulino wrote:
> On Tue, 10 Dec 2013 15:25:07 +0100
> Kevin Wolf <kwolf@redhat.com> wrote:
>
>> My objection to your approach is strong because Beno=C3=AEt already se=
nt an
>> alternative which I believe is less worse because with it, arguments
>> actually mean what their names tell instead of having additional bools
>> for "oh, and I said A, but I didn't mean it, I really want B".
>
> Current proposal:
>
> { 'command': 'block_passwd', 'data': {'*device': 'str',
>                                        '*node-name': 'str', 'password':=
 'str'} }
>

I vote for this.

> When I look at it, I ask myself:
>
>   - What happens when device=3DNULL?
>
>   - What happens when node-name=3DNULL?
>
>   - What happens when device=3DNULL and node-name=3DNULL?
>
>   - What happens when device !=3D NULL and node-node !=3D NULL?
>
>   - What happens when device !=3D NULL but node-node=3DNULL?
>
>   - What happens when device=3DNULL but node-node !=3D NULL?
>
> My proposal:
>
> { 'command': 'block_passwd', 'data': {'device': 'str',
>                                        '*device-is-node': 'bool', 'pass=
word': 'str'} }
>
>   - What happens when device-is-node=3DNULL?
>
>   - What happens when device-is-node !=3D NULL?
>

I think our starting point is that device names and node names are=20
separate name spaces. For this reason we should avoid connecting them by=20
reusing one field. From a user's view, "device-is-node", or anything=20
meaning this, just doesn't sound interesting, because we also told them=20
"device-is-not-node".

Fam