Re: [PATCH 1/2] qapi: block-dirty-bitmap-merge: support allocation maps

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

27.04.2021 14:11, Vladimir Sementsov-Ogievskiy wrote:
> Add possibility to merge allocation map of specified node into target
> bitmap.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy<vsementsov@virtuozzo.com>
> ---
>   qapi/block-core.json            | 31 +++++++++++++++++--
>   include/block/block_int.h       |  4 +++
>   block/dirty-bitmap.c            | 42 +++++++++++++++++++++++++
>   block/monitor/bitmap-qmp-cmds.c | 55 ++++++++++++++++++++++++++++-----
>   4 files changed, 122 insertions(+), 10 deletions(-)
> 
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 6d227924d0..0fafb043bc 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -2006,6 +2006,32 @@
>     'data': { 'node': 'str', 'name': 'str', '*granularity': 'uint32',
>               '*persistent': 'bool', '*disabled': 'bool' } }
>   
> +##
> +# @AllocationMapMode:
> +#
> +# An enumeration of possible allocation maps that could be merged into target
> +# bitmap.
> +#
> +# @top: The allocation status of the top layer of the attached storage node.
> +#
> +# Since: 6.1
> +##
> +{ 'enum': 'AllocationMapMode',
> +  'data': ['top'] }
> +
> +##
> +# @BlockDirtyBitmapMergeExternalSource:
> +#
> +# @node: name of device/node which the bitmap is tracking
> +#
> +# @name: name of the dirty bitmap
> +#
> +# Since: 6.1
> +##
> +{ 'struct': 'BlockDirtyBitmapMergeExternalSource',
> +  'data': { 'node': 'str', '*name': 'str',
> +            '*allocation-map': 'AllocationMapMode' } }
> +
>   ##
>   # @BlockDirtyBitmapMergeSource:
>   #
> @@ -2017,7 +2043,7 @@
>   ##
>   { 'alternate': 'BlockDirtyBitmapMergeSource',
>     'data': { 'local': 'str',
> -            'external': 'BlockDirtyBitmap' } }
> +            'external': 'BlockDirtyBitmapMergeExternalSource' } }
>   
>   ##
>   # @BlockDirtyBitmapMerge:
> @@ -2176,7 +2202,8 @@
>   #
>   ##
>   { 'command': 'block-dirty-bitmap-merge',
> -  'data': 'BlockDirtyBitmapMerge' }
> +  'data': 'BlockDirtyBitmapMerge',
> +  'coroutine': true }
>   
>   ##


So, what I propose makes possible to issue the following command:

block-dirty-bitmap-merge
   bitmaps: [{"allocation-map": "top", "node": "drive0"}]
   node: target-node-name
   target: target-bitmap-name


I've discussed it with Nikolay, and he requested a possibility of querying allocation status of base..top sub-chain (assume several snapshots was done without creating bitmaps, and we want to restore the bitmap for backup).

So, we actually want something like

block-dirty-bitmap-merge
   bitmaps: [{top: "tpp-node-name", bottom: "bottom-node-name"}]
   node: target-node-name
   target: target-bitmap-name


-- 
Best regards,
Vladimir