Re: [Qemu-devel] [RFC PATCH 02/10] block/qapi: Add qcow2 create options to schema

[Eric Blake]

On 01/11/2018 01:52 PM, Kevin Wolf wrote:
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
>  qapi/block-core.json | 33 ++++++++++++++++++++++++++++++++-
>  1 file changed, 32 insertions(+), 1 deletion(-)
> 
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 1749376c61..9341f6708d 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -3320,6 +3320,37 @@
>  { 'command': 'blockdev-del', 'data': { 'node-name': 'str' } }
>  
>  ##
> +# @BlockdevQcow2CompatLevel:
> +# @0_10:    The original QCOW2 format as introduced in qemu 0.10 (version 2)
> +# @1_1:     The extended QCOW2 format as introduced in qemu 1.1 (version 3)
> +#
> +# Since: 2.10
> +##
> +{ 'enum': 'BlockdevQcow2CompatLevel',
> +  'data': [ '0_10', '1_1' ] }

Enums are allowed to start with digits while struct members are not; so
you can get away with this naming.  Do we really want the names 0_10 and
1_1, or are there better names we could come up with (it already
undergoes translation such that qemu-img reports 0.10 rather than 0_10).

> +
> +
> +##
> +# @BlockdevCreateOptionsQcow2:
> +#
> +# Driver specific image creation options for qcow2.
> +#
> +# TODO Describe fields

Hence this being RFC :)

> +#
> +# Since: 2.12
> +##
> +{ 'struct': 'BlockdevCreateOptionsQcow2',
> +  'data': { 'size':             'size',

Is size mandatory even when we have a backing file specification?  It is
not mandatory for qemu-img create; but on the other hand, I think I can
live with requiring the QMP caller to supply a size.

> +            '*compat':          'BlockdevQcow2CompatLevel',
> +            '*backing-file':    'str',

Given Dan's comments, perhaps name this one 'backing-str' to make it
obvious that it is the string written into the qcow2 header, rather than
the node we open as backing?  Or, maybe we support an optional
'*backing-node' that can be used for allowing a default size and backing
string if not explicitly overridden?

> +            '*backing-fmt':     'BlockdevDriver',
> +            '*encrypt':         'QCryptoBlockCreateOptions',
> +            '*cluster-size':    'size',
> +            '*preallocation':   'PreallocMode',
> +            '*lazy-refcounts':  'bool',
> +            '*refcount-bits':   'int' } }
> +
> +##
>  # @BlockdevCreateDummy:
>  #
>  # FIXME To be removed. Only there to make the QAPI generator happy while 
> we're
> @@ -3365,7 +3396,7 @@
>        'null-aio':       'BlockdevCreateDummy',
>        'null-co':        'BlockdevCreateDummy',
>        'parallels':      'BlockdevCreateDummy',
> -      'qcow2':          'BlockdevCreateDummy',
> +      'qcow2':          'BlockdevCreateOptionsQcow2',
>        'qcow':           'BlockdevCreateDummy',
>        'qed':            'BlockdevCreateDummy',
>        'quorum':         'BlockdevCreateDummy',
> 

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

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