Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru> writes:
> For change, pause, resume, complete, dismiss and finalize actions
> corresponding job- and block-job commands are almost equal. The
> difference is in find_block_job_locked() vs find_job_locked()
> functions. What's different?
>
> 1. find_block_job_locked() do check, is found job a block-job. This OK
> when moving to more generic API, no needs to document this change.
>
> 2. find_block_job_locked() reports DeviceNotActive on failure, when
> find_job_locked() reports GenericError. So, lets document this
> difference in deprecated.txt. Still, for dismiss and finalize errors
> are not documented at all, so be silent in deprecated.txt as well.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>
> ---
>
> Hi all!
>
> That's a continuation of my "[RFC 00/15] block job API"[1], exactly, the
> simplest part of it - deprecating block-job-* commands which simply
> duplicate job-* ones.
>
> Note that the old series was started with trying to introduce job-change
> command as substitution to both block-job-change (which only can change
> mirror copy-mode parameter), and block-job-set-speed. It was rather
> complicated and controversial attempt, which latest implemenation was
> "[PATCH v3 0/7] introduce job-change qmp command"[2].
>
> In [2] Kevin noted, that we'd better follow existing blockdev-reopen
> approach of changing options (i.e. specify all options) than introduce a
> new one. But, on the other hand, now I'm afraid, that rewriting in
> third tools simple call to (old good) block-job-set-speed into
> job-change(_all_options_ + changed speed) is too much work just for
> "having nice interface". And too much for the only two options we want
> to change.
>
> So, let's just start from something more obvious. Finally,
> we can simple keep block-job-set-speed and block-job-change as is,
> as they (unlike other block-job-* commands) are not duplicated by
> similar job-* commands.
>
> [1]
> https://patchew.org/QEMU/20240313150907.623462-1-vsement...@yandex-team.ru/
> [2]
> https://patchew.org/QEMU/20241002140616.561652-1-vsement...@yandex-team.ru/
Thank you for your efforts at making the interfaces cleaner, simpler,
and less redundant.
> docs/about/deprecated.rst | 31 +++++++++++++++++++++++++++++++
> qapi/block-core.json | 30 ++++++++++++++++++++++++++++++
> 2 files changed, 61 insertions(+)
>
> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
> index e2b4f077d4..eed3356359 100644
> --- a/docs/about/deprecated.rst
> +++ b/docs/about/deprecated.rst
> @@ -148,6 +148,37 @@ options are removed in favor of using explicit
> ``blockdev-create`` and
> ``blockdev-add`` calls. See :doc:`/interop/live-block-operations` for
> details.
>
> +``block-job-pause`` (since 10.1)
> +'''''''''''''''''''''''''''''''
> +
> +Use ``job-pause`` instead. The only difference is that ``job-pause``
> +always reports GenericError on failure when ``block-job-pause`` reports
> +DeviceNotActive when block-job is not found.
block-job-pause's doc comment:
# The operation will pause as soon as possible. No event is emitted
# when the operation is actually paused. [...]
job-pause's:
# The job will pause as soon as possible, which means transitioning
# into the PAUSED state if it was RUNNING, or into STANDBY if it was
# READY. The corresponding JOB_STATUS_CHANGE event will be emitted.
Either one of them is incorrect about event emission, or there is
another difference.
> +
> +``block-job-resume`` (since 10.1)
> +''''''''''''''''''''''''''''''''
> +
> +Use ``job-resume`` instead. The only difference is that ``job-resume``
> +always reports GenericError on failure when ``block-job-resume`` reports
> +DeviceNotActive when block-job is not found.
block-job-resume's doc comment:
# This command also clears the error status of the job.
Nothing like that job-resume's. Either one of them is incorrect /
incomplete about the error status clearance, or there is another
difference.
> +
> +``block-job-complete`` (since 10.1)
> +''''''''''''''''''''''''''''''''''
> +
> +Use ``job-complete`` instead. The only difference is that ``job-complete``
> +always reports GenericError on failure when ``block-job-complete`` reports
> +DeviceNotActive when block-job is not found.
block-job-complete's doc comment:
# Manually trigger completion of an active background block operation.
# This is supported for drive mirroring, where it also switches the
# device to write to the target path only. The ability to complete is
# signaled with a BLOCK_JOB_READY event.
#
# This command completes an active background block operation
# synchronously. The ordering of this command's return with the
# BLOCK_JOB_COMPLETED event is not defined. Note that if an I/O error
# occurs during the processing of this command: 1) the command itself
# will fail; 2) the error will be processed according to the
# rerror/werror arguments that were specified when starting the
# operation.
job-complete's:
# Manually trigger completion of an active job in the READY state.
Is the latter lacking useful information?
> +
> +``block-job-dismiss`` (since 10.1)
> +'''''''''''''''''''''''''''''''''
> +
> +Use ``job-dismiss`` instead.
block-job-dismiss's doc comment:
# For jobs that have already concluded, remove them from the
# block-job-query list. This command only needs to be run for jobs
# which were started with QEMU 2.12+ job lifetime management
# semantics.
I figure "started with QEMU 2.12+ job lifetime management semantics" is
an awkward way to say "auto-dismiss is false".
job-dismiss's doc comment:
# Deletes a job that is in the CONCLUDED state. This command only
# needs to be run explicitly for jobs that don't have automatic
# dismiss enabled.
@auto-dismiss defaults to true for jobs that support controlling it:
drive-backup, blockdev-backup, block-commit, drive-mirror,
blockdev-mirror, block-stream. I guess these are exactly the commands
that already existed when we added "QEMU 2.12+ lifetime management".
I figure it's always false for the other jobs, but that doesn't seem to
be documented anywhere.
> +
> +``block-job-finalize`` (since 10.1)
> +''''''''''''''''''''''''''''''''''
> +
> +Use ``job-finalize`` instead.
> +
block-job-finalize's doc comment:
# Once a job that has manual=true reaches the pending state, it can be
# instructed to finalize any graph changes and do any necessary
# cleanup via this command. [...]
There is no member @manual anywhere in the QAPI schema. I figure this
should be @auto-finalize.
job-finalize's doc comment:
# Instructs all jobs in a transaction (or a single job if it is not
# part of any transaction) to finalize any graph changes and do any
# necessary cleanup. This command requires that all involved jobs are
# in the PENDING state.
Nothing on @auto-finalize.
@auto-finalize defaults to true for jobs that support controlling it.
These are exactly the ones that support @auto-dismiss.
I figure @auto-dismiss is always false for the other jobs, but that
doesn't seem to be documented anywhere.
The only other bits related to @auto-dismiss and @auto-finalize seem to
be two states in JobStatus:
# @pending: The job has finished its work, but has finalization steps
# that it needs to make prior to completing. These changes will
# require manual intervention via @job-finalize if auto-finalize
# was set to false. These pending changes may still fail.
[...]
# @concluded: The job has finished all work. If auto-dismiss was set
# to false, the job will remain in the query list until it is
# dismissed via @job-dismiss.
Is it possible to observe @concluded via QMP when @auto-dismiss is on?
What about @pending?
Aside: getting rid of auto-dismiss and auto-finalize some day would be
nice.
> ``query-migrationthreads`` (since 9.2)
> ''''''''''''''''''''''''''''''''''''''
>
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index b1937780e1..264be8413b 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -2968,6 +2968,11 @@
> # the name of the parameter), but since QEMU 2.7 it can have other
> # values.
> #
> +# Features:
> +#
> +# @deprecated: This command is deprecated. Use @job-pause
> +# instead.
> +#
> # Errors:
> # - If no background operation is active on this device,
> # DeviceNotActive
> @@ -2975,6 +2980,7 @@
> # Since: 1.3
> ##
> { 'command': 'block-job-pause', 'data': { 'device': 'str' },
> + 'features': ['deprecated'],
> 'allow-preconfig': true }
>
> ##
> @@ -2992,6 +2998,11 @@
> # the name of the parameter), but since QEMU 2.7 it can have other
> # values.
> #
> +# Features:
> +#
> +# @deprecated: This command is deprecated. Use @job-resume
> +# instead.
> +#
> # Errors:
> # - If no background operation is active on this device,
> # DeviceNotActive
> @@ -2999,6 +3010,7 @@
> # Since: 1.3
> ##
> { 'command': 'block-job-resume', 'data': { 'device': 'str' },
> + 'features': ['deprecated'],
> 'allow-preconfig': true }
>
> ##
> @@ -3023,6 +3035,11 @@
> # the name of the parameter), but since QEMU 2.7 it can have other
> # values.
> #
> +# Features:
> +#
> +# @deprecated: This command is deprecated. Use @job-complete
> +# instead.
> +#
> # Errors:
> # - If no background operation is active on this device,
> # DeviceNotActive
> @@ -3030,6 +3047,7 @@
> # Since: 1.3
> ##
> { 'command': 'block-job-complete', 'data': { 'device': 'str' },
> + 'features': ['deprecated'],
> 'allow-preconfig': true }
>
> ##
> @@ -3047,9 +3065,15 @@
> #
> # @id: The job identifier.
> #
> +# Features:
> +#
> +# @deprecated: This command is deprecated. Use @job-dismiss
> +# instead.
> +#
> # Since: 2.12
> ##
> { 'command': 'block-job-dismiss', 'data': { 'id': 'str' },
> + 'features': ['deprecated'],
> 'allow-preconfig': true }
>
> ##
> @@ -3064,9 +3088,15 @@
> #
> # @id: The job identifier.
> #
> +# Features:
> +#
> +# @deprecated: This command is deprecated. Use @job-finalize
> +# instead.
> +#
> # Since: 2.12
> ##
> { 'command': 'block-job-finalize', 'data': { 'id': 'str' },
> + 'features': ['deprecated'],
> 'allow-preconfig': true }
>
> ##
