Re: [Qemu-devel] [PATCH v11 2/3] qemu-img info lists bitmap directory entries

[Markus Armbruster <armbru@redhat.com>]

Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> writes:

> In the 'Format specific information' section of the 'qemu-img info'
> command output, the supplemental information about existing QCOW2
> bitmaps will be shown, such as a bitmap name, flags and granularity:
>
> image: /vz/vmprivate/VM1/harddisk.hdd
> file format: qcow2
> virtual size: 64G (68719476736 bytes)
> disk size: 3.0M
> cluster_size: 1048576
> Format specific information:
>     compat: 1.1
>     lazy refcounts: true
>     bitmaps:
>         [0]:
>             flags:
>                 [0]: in-use
>                 [1]: auto
>             name: back-up1
>             unknown flags: 4
>             granularity: 65536
>         [1]:
>             flags:
>                 [0]: in-use
>                 [1]: auto
>             name: back-up2
>             unknown flags: 8
>             granularity: 65536
>     refcount bits: 16
>     corrupt: false
>
> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> ---
[...]
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 91685be..271e0df 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -69,6 +69,8 @@
>  # @encrypt: details about encryption parameters; only set if image
>  #           is encrypted (since 2.10)
>  #
> +# @bitmaps: A list of qcow2 bitmap details (since 4.0)
> +#
>  # Since: 1.7
>  ##
>  { 'struct': 'ImageInfoSpecificQCow2',
> @@ -77,7 +79,8 @@
>        '*lazy-refcounts': 'bool',
>        '*corrupt': 'bool',
>        'refcount-bits': 'int',
> -      '*encrypt': 'ImageInfoSpecificQCow2Encryption'
> +      '*encrypt': 'ImageInfoSpecificQCow2Encryption',
> +      '*bitmaps': ['Qcow2BitmapInfo']
>    } }
>  
>  ##
> @@ -454,6 +457,41 @@
>             'status': 'DirtyBitmapStatus'} }
>  
>  ##
> +# @Qcow2BitmapInfoFlags:
> +#
> +# An enumeration of flags that a bitmap can report to the user.
> +#
> +# @in-use: The bitmap was not saved correctly and may be inconsistent.

I doubt the casual reader could guess the meaning from the name.  What
about @dirty?

> +#
> +# @auto: The bitmap must reflect all changes of the virtual disk by any
> +#        application that would write to this qcow2 file.
> +#
> +# Since: 4.0
> +##
> +{ 'enum': 'Qcow2BitmapInfoFlags',
> +  'data': ['in-use', 'auto'] }
> +
> +##
> +# @Qcow2BitmapInfo:
> +#
> +# Qcow2 bitmap information.
> +#
> +# @name: the name of the bitmap
> +#
> +# @granularity: granularity of the bitmap in bytes
> +#
> +# @flags: recognized flags of the bitmap
> +#
> +# @unknown-flags: any remaining flags not recognized by the current qemu version

Intended use cases for @unknown-flags?

> +#
> +# Since: 4.0
> +##
> +{ 'struct': 'Qcow2BitmapInfo',
> +  'data': {'name': 'str', 'granularity': 'uint32',
> +           'flags': ['Qcow2BitmapInfoFlags'],
> +           '*unknown-flags': 'uint32' } }
> +
> +##
>  # @BlockLatencyHistogramInfo:
>  #
>  # Block latency histogram.