Fiona Ebner <f.eb...@proxmox.com> writes:
> In the context of backup fleecing, discarding the source will not work
> when the fleecing image has a larger granularity than the one used for
> block-copy operations (can happen if the backup target has smaller
> cluster size), because cbw_co_pdiscard_snapshot() will align down the
> discard requests and thus effectively ignore then.
>
> To make @discard-source work in such a scenario, allow specifying the
> minimum cluster size used for block-copy operations and thus in
> particular also the granularity for discard requests to the source.
>
> Suggested-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>
> Signed-off-by: Fiona Ebner <f.eb...@proxmox.com>
[...]
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 8fc0a4b234..f1219a9dfb 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -1551,11 +1551,16 @@
> # it should not be less than job cluster size which is calculated
> # as maximum of target image cluster size and 64k. Default 0.
> #
> +# @min-cluster-size: Minimum size of blocks used by copy-before-write
> +# and background copy operations. Has to be a power of 2. No
> +# effect if smaller than the maximum of the target's cluster size
> +# and 64 KiB. Default 0. (Since 9.1)
> +#
> # Since: 6.0
> ##
> { 'struct': 'BackupPerf',
> - 'data': { '*use-copy-range': 'bool',
> - '*max-workers': 'int', '*max-chunk': 'int64' } }
> + 'data': { '*use-copy-range': 'bool', '*max-workers': 'int',
> + '*max-chunk': 'int64', '*min-cluster-size': 'size' } }
>
> ##
> # @BackupCommon:
QAPI schema
Acked-by: Markus Armbruster <arm...@redhat.com>
