Re: [Qemu-devel] [PATCH V5 02/10] qapi/block-core: add Qcow2Compress parameters

[Eric Blake <eblake@redhat.com>]

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On 07/25/2017 09:41 AM, Peter Lieven wrote:
> Signed-off-by: Peter Lieven <pl@kamp.de>
> ---
>  qapi/block-core.json | 40 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 40 insertions(+)
> 
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 833c602..f652206 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -2455,6 +2455,46 @@
>              '*encrypt': 'BlockdevQcow2Encryption' } }
>  
>  ##
> +# @Qcow2CompressFormat:
> +#
> +# @deflate: standard zlib deflate compression
> +#
> +# Since: 2.11
> +##
> +{ 'enum': 'Qcow2CompressFormat',
> +  'data': [ 'deflate' ] }
> +
> +##
> +# @Qcow2CompressDeflate:
> +#
> +# @level: specifies the compression level. 0 = default compression,
> +#         1 = fastest compression, 9 = best compresion

By putting level here instead of in the common base type, you'll have to
re-implement it for each compression type - but that's also okay since
they (might) have different ranges of valid levels.

s/compresion/compression/

maybe: 0 = default compression (same as level 6), 1=...


> +# @window-size: specifies the window size used for deflate compression.
> +#               8...15 = window size of 2^8 to 2^15 byte (default)

15 is the new default, but it might be worth an explicit mention that a
window of 12 is required for back-compat to older images.

> +#
> +# Since: 2.11
> +##
> +{ 'struct': 'Qcow2CompressDeflate',
> +  'data': { '*level': 'uint8',
> +            '*window-size': 'uint8' } }
> +
> +##
> +# @Qcow2Compress:
> +#
> +# Specifies the compression format and compression level that should
> +# be used for compressed Qcow2 clusters.
> +#
> +# @format: specifies the compression format to use. (defaults to zlib)

s/zlib/deflate/

> +#
> +# Since: 2.11
> +##
> +{ 'union': 'Qcow2Compress',
> +  'base': { 'format': 'Qcow2CompressFormat' },
> +  'discriminator': 'format',
> +  'data': { 'deflate': 'Qcow2CompressDeflate' } }
> +
> +
> +##
>  # @BlockdevOptionsSsh:
>  #
>  # @server:              host address
> 

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


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