Re: [PATCH v4 2/7] qapi: Make parameter 'file' optional for BlockdevCreateOptionsLUKS

[Yong Huang <yong.huang@smartx.com>]

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On Tue, Feb 20, 2024 at 2:31 PM Markus Armbruster <armbru@redhat.com> wrote:

> yong.huang@smartx.com writes:
>
> > From: Hyman Huang <yong.huang@smartx.com>
> >
> > To support detached LUKS header creation, make the existing 'file'
> > field in BlockdevCreateOptionsLUKS optional.
> >
> > Signed-off-by: Hyman Huang <yong.huang@smartx.com>
> > Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
>
> [...]
>
> > diff --git a/qapi/block-core.json b/qapi/block-core.json
> > index ae604c6019..69a88d613d 100644
> > --- a/qapi/block-core.json
> > +++ b/qapi/block-core.json
> > @@ -4957,7 +4957,8 @@
> >  #
> >  # Driver specific image creation options for LUKS.
> >  #
> > -# @file: Node to create the image format on
> > +# @file: Node to create the image format on, mandatory except when
> > +#        'preallocation' is not requested
>
> You mean when @preallocation is "off"?
>
> Cases:
>
> 1. @file is mandatory
>

When @preallocation is specified to PREALLOC_MODE_ON, file
is mandatory because preallocation aims to act on payload data that
@file holds.


> 2. @file is optional and present
>

When @preallocation is not specified or equals to PREALLOC_MODE_OFF,
@file if optional.
If @file present，there are two cases:
1. @header is absent,  the creation process degenerate to the origin action.
2. @header is present,  the creation process would trunk the payload data
image that @file holds and do the LUKS formatting on the image that
@header refers;


>
> 3. @file is optional and absent
>

When @preallocation is not specified or equals to PREALLOC_MODE_OFF,
@file if optional.
If @file is absent, do the LUKS formatting only.
Note that Either the parameter 'header' or 'file' must be specified.

Here's my interpretation; do let me know if any of the points are off or
need to be refactored.


>
> Ignorant question: behavior in each case?
>
> >  #
> >  # @size: Size of the virtual disk in bytes
> >  #
> > @@ -4968,7 +4969,7 @@
> >  ##
> >  { 'struct': 'BlockdevCreateOptionsLUKS',
> >    'base': 'QCryptoBlockCreateOptionsLUKS',
> > -  'data': { 'file':             'BlockdevRef',
> > +  'data': { '*file':            'BlockdevRef',
> >              'size':             'size',
> >              '*preallocation':   'PreallocMode' } }
>
>
Thanks,

Yong

-- 
Best regards

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