Re: [RFC 2/6] migration: migrate 'inc' command option is deprecated.

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Jun 12, 2023 at 09:33:40PM +0200, Juan Quintela wrote:
> Use 'migrate_set_parameter block_incremental true' instead.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> ---
>  docs/about/deprecated.rst |  7 +++++++
>  qapi/migration.json       | 11 +++++++++--
>  migration/migration.c     |  5 +++++
>  3 files changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
> index e1aa0eafc8..c75a3a8f5a 100644
> --- a/docs/about/deprecated.rst
> +++ b/docs/about/deprecated.rst
> @@ -433,3 +433,10 @@ Migration
>  ``skipped`` field in Migration stats has been deprecated.  It hasn't
>  been used for more than 10 years.
>  
> +``inc`` migrate command option (since 8.1)
> +''''''''''''''''''''''''''''''''''''''''''
> +
> +The new way to modify migration is using migration parameters.
> +``inc`` functionality can be acchieved using
> +``migrate_set_parameter block-incremental true``.

This is a HMP command, but the change affects QMP too. I'd suggest

 ``inc`` functionality can be achieved by setting the
 ``block-incremental`` migration parameter to ``true``.


> +
> diff --git a/qapi/migration.json b/qapi/migration.json
> index bcae193733..4ee28df6da 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -1424,13 +1424,19 @@
>  #
>  # @blk: do block migration (full disk copy)
>  #
> -# @inc: incremental disk copy migration
> +# @inc: incremental disk copy migration.  This option is deprecated.
> +#    Use 'migrate_set_parameter block-incremetantal true' instead.

  @inc: incremental disk copy migration.  This option is deprecated.
    Set the 'block-incremetantal' migration parameter to 'true' instead.


>  #
>  # @detach: this argument exists only for compatibility reasons and is
>  #     ignored by QEMU
>  #
>  # @resume: resume one paused migration, default "off". (since 3.0)
>  #
> +# Features:
> +#
> +# @deprecated: option @inc is better set with
> +#     'migrate_set_parameter block-incremental true'.

  # @deprecated: option @inc should be enabled by 
  #     setting the 'block-incremental' migration parameter to 'true'.

> +#
>  # Returns: nothing on success
>  #
>  # Since: 0.14
> @@ -1452,7 +1458,8 @@
>  # <- { "return": {} }
>  ##
>  { 'command': 'migrate',
> -  'data': {'uri': 'str', '*blk': 'bool', '*inc': 'bool',
> +  'data': {'uri': 'str', '*blk': 'bool',
> +           '*inc': { 'type': 'bool', 'features': ['deprecated'] },
>             '*detach': 'bool', '*resume': 'bool' } }
>  
>  ##
> diff --git a/migration/migration.c b/migration/migration.c
> index dc05c6f6ea..7ebce7c7bf 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -1544,6 +1544,11 @@ static bool migrate_prepare(MigrationState *s, bool blk, bool blk_inc,
>  {
>      Error *local_err = NULL;
>  
> +    if (blk_inc) {
> +        warn_report("-inc migrate option is deprecated, use"
> +                    "'migrate_set_parameter block-incremental true' instead.");

        warn_report("-inc migrate option is deprecated, set the"
                    "'block-incremental' migration parameter to 'true' instead.");

With regards,
Daniel
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