On 8/14/19 6:07 AM, Vladimir Sementsov-Ogievskiy wrote:
> To get rid of implicit filters related workarounds in future let's
> deprecate them now.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
> ---
> qemu-deprecated.texi | 7 +++++++
> qapi/block-core.json | 6 ++++--
> include/block/block_int.h | 10 +++++++++-
> blockdev.c | 10 ++++++++++
> 4 files changed, 30 insertions(+), 3 deletions(-)
>
> diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi
> index 2753fafd0b..8222440148 100644
> --- a/qemu-deprecated.texi
> +++ b/qemu-deprecated.texi
> @@ -183,6 +183,13 @@ the 'wait' field, which is only applicable to sockets in
> server mode
>
> Use blockdev-mirror and blockdev-backup instead.
>
> +@subsection implicit filters (since 4.2)
> +
> +Mirror and commit jobs inserts filters, which becomes implicit if user
> +omitted filter-node-name parameter. So omitting it is deprecated, set it
> +always. Note, that drive-mirror don't have this parameter, so it will
> +create implicit filter anyway, but drive-mirror is deprecated itself too.
> +
> @section Human Monitor Protocol (HMP) commands
>
> @subsection The hub_id parameter of 'hostfwd_add' / 'hostfwd_remove' (since
> 3.1)
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 4e35526634..0505ac9d8b 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -1596,7 +1596,8 @@
> # @filter-node-name: the node name that should be assigned to the
> # filter driver that the commit job inserts into the graph
> # above @top. If this option is not given, a node name is
> -# autogenerated. (Since: 2.9)
> +# autogenerated. Omitting this option is deprecated, it
> will
> +# be required in future. (Since: 2.9)
> #
> # @auto-finalize: When false, this job will wait in a PENDING state after it
> has
> # finished its work, waiting for @block-job-finalize before
> @@ -2249,7 +2250,8 @@
> # @filter-node-name: the node name that should be assigned to the
> # filter driver that the mirror job inserts into the graph
> # above @device. If this option is not given, a node name
> is
> -# autogenerated. (Since: 2.9)
> +# autogenerated. Omitting this option is deprecated, it
> will
> +# be required in future. (Since: 2.9)
> #
> # @copy-mode: when to copy data to the destination; defaults to 'background'
> # (Since: 3.0)
> diff --git a/include/block/block_int.h b/include/block/block_int.h
> index 3aa1e832a8..624da0b4a2 100644
> --- a/include/block/block_int.h
> +++ b/include/block/block_int.h
> @@ -762,7 +762,15 @@ struct BlockDriverState {
> bool sg; /* if true, the device is a /dev/sg* */
> bool probed; /* if true, format was probed rather than specified */
> bool force_share; /* if true, always allow all shared permissions */
> - bool implicit; /* if true, this filter node was automatically inserted
> */
> +
> + /*
> + * @implicit field is deprecated, don't set it to true for new filters.
> + * If true, this filter node was automatically inserted and user don't
> + * know about it and unprepared for any effects of it. So, implicit
> + * filters are workarounded and skipped in many places of the block
> + * layer code.
> + */
> + bool implicit;
>
> BlockDriver *drv; /* NULL means no media */
> void *opaque;
> diff --git a/blockdev.c b/blockdev.c
> index 36e9368e01..b3cfaccce1 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -3292,6 +3292,11 @@ void qmp_block_commit(bool has_job_id, const char
> *job_id, const char *device,
> BlockdevOnError on_error = BLOCKDEV_ON_ERROR_REPORT;
> int job_flags = JOB_DEFAULT;
>
> + if (!has_filter_node_name) {
> + warn_report("Omitting filter-node-name parameter is deprecated, it "
> + "will be required in future");
> + }
> +
> if (!has_speed) {
> speed = 0;
> }
> @@ -3990,6 +3995,11 @@ void qmp_blockdev_mirror(bool has_job_id, const char
> *job_id,
> Error *local_err = NULL;
> int ret;
>
> + if (!has_filter_node_name) {
> + warn_report("Omitting filter-node-name parameter is deprecated, it "
> + "will be required in future");
> + }
> +
> bs = qmp_get_root_bs(device, errp);
> if (!bs) {
> return;
>
This might be OK to do right away, though.
I asked Markus this not too long ago; do we want to amend the QAPI
schema specification to allow commands to return with "Warning" strings,
or "Deprecated" stings to allow in-band deprecation notices for cases
like these?
example:
{ "return": {},
"deprecated": True,
"warning": "Omitting filter-node-name parameter is deprecated, it will
be required in the future"
}
There's no "error" key, so this should be recognized as success by
compatible clients, but they'll definitely see the extra information.
Part of my motivation is to facilitate a more aggressive deprecation of
legacy features by ensuring that we are able to rigorously notify users
through any means that they need to adjust their scripts.
--js
