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Re: [Qemu-devel] [RFC v3 05/14] blockjobs: add block_job_dismiss
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [RFC v3 05/14] blockjobs: add block_job_dismiss |
Date: |
Mon, 29 Jan 2018 18:38:02 +0100 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
Am 27.01.2018 um 03:05 hat John Snow geschrieben:
> For jobs that have reached their terminal state, prior to having their
> last reference put down (meaning jobs that have completed successfully,
> unsuccessfully, or have been canceled), allow the user to dismiss the
> job's lingering status report via block-job-dismiss.
>
> This gives management APIs the chance to conclusively determine if a job
> failed or succeeded, even if the event broadcast was missed.
>
> Note that jobs do not yet linger in any such state, they are freed
> immediately upon reaching this previously-unnamed state. such a state is
> added immediately in the next commit.
>
> Valid objects:
> Concluded: (added in a future commit); dismisses the concluded job.
>
> Signed-off-by: John Snow <address@hidden>
> ---
> block/trace-events | 1 +
> blockdev.c | 14 ++++++++++++++
> blockjob.c | 30 ++++++++++++++++++++++++++++++
> include/block/blockjob.h | 9 +++++++++
> qapi/block-core.json | 19 +++++++++++++++++++
> 5 files changed, 73 insertions(+)
>
> diff --git a/block/trace-events b/block/trace-events
> index 11c8d5f590..8f61566770 100644
> --- a/block/trace-events
> +++ b/block/trace-events
> @@ -46,6 +46,7 @@ qmp_block_job_cancel(void *job) "job %p"
> qmp_block_job_pause(void *job) "job %p"
> qmp_block_job_resume(void *job) "job %p"
> qmp_block_job_complete(void *job) "job %p"
> +qmp_block_job_dismiss(void *job) "job %p"
> qmp_block_stream(void *bs, void *job) "bs %p job %p"
>
> # block/file-win32.c
> diff --git a/blockdev.c b/blockdev.c
> index 2c0773bba7..5e8edff322 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -3849,6 +3849,20 @@ void qmp_block_job_complete(const char *device, Error
> **errp)
> aio_context_release(aio_context);
> }
>
> +void qmp_block_job_dismiss(const char *id, Error **errp)
> +{
> + AioContext *aio_context;
> + BlockJob *job = find_block_job(id, &aio_context, errp);
> +
> + if (!job) {
> + return;
> + }
> +
> + trace_qmp_block_job_dismiss(job);
> + block_job_dismiss(&job, errp);
> + aio_context_release(aio_context);
> +}
> +
> void qmp_change_backing_file(const char *device,
> const char *image_node_name,
> const char *backing_file,
> diff --git a/blockjob.c b/blockjob.c
> index ea216aca5e..5531f5c2ab 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -58,6 +58,7 @@ enum BlockJobVerb {
> BLOCK_JOB_VERB_RESUME,
> BLOCK_JOB_VERB_SET_SPEED,
> BLOCK_JOB_VERB_COMPLETE,
> + BLOCK_JOB_VERB_DISMISS,
> BLOCK_JOB_VERB__MAX
> };
>
> @@ -68,6 +69,7 @@ bool
> BlockJobVerb[BLOCK_JOB_VERB__MAX][BLOCK_JOB_STATUS__MAX] = {
> [BLOCK_JOB_VERB_RESUME] = {0, 0, 0, 1, 0},
> [BLOCK_JOB_VERB_SET_SPEED] = {0, 1, 1, 1, 1},
> [BLOCK_JOB_VERB_COMPLETE] = {0, 0, 0, 0, 1},
> + [BLOCK_JOB_VERB_DISMISS] = {0, 0, 0, 0, 0},
This makes it very obvious that the patches should probably be
reordered.
> };
>
> static void block_job_state_transition(BlockJob *job, BlockJobStatus s1)
> @@ -426,6 +428,13 @@ static void block_job_cancel_async(BlockJob *job)
> job->cancelled = true;
> }
>
> +static void block_job_do_dismiss(BlockJob *job)
> +{
> + assert(job && job->manual == true);
> + block_job_state_transition(job, BLOCK_JOB_STATUS_UNDEFINED);
I don't think you made that an allowed transition from anywhere?
> + block_job_unref(job);
> +}
> +
> static int block_job_finish_sync(BlockJob *job,
> void (*finish)(BlockJob *, Error **errp),
> Error **errp)
> @@ -455,6 +464,9 @@ static int block_job_finish_sync(BlockJob *job,
> aio_poll(qemu_get_aio_context(), true);
> }
> ret = (job->cancelled && job->ret == 0) ? -ECANCELED : job->ret;
> + if (job->manual) {
> + block_job_do_dismiss(job);
> + }
> block_job_unref(job);
> return ret;
> }
> @@ -570,6 +582,24 @@ void block_job_complete(BlockJob *job, Error **errp)
> job->driver->complete(job, errp);
> }
>
> +void block_job_dismiss(BlockJob **jobptr, Error **errp)
> +{
> + BlockJob *job = *jobptr;
> + /* similarly to _complete, this is QMP-interface only. */
> + assert(job->id);
> + if (!job->manual) {
> + error_setg(errp, "The active block job '%s' was not started with "
> + "\'manual\': true, and so cannot be dismissed as it will "
> + "clean up after itself automatically", job->id);
> + return;
> + }
If you check instead that the job is in the right state to be dismissed
(CONCLUDED), the job->manual check wouldn't be needed any more because
the user can never catch an automatically completed job in CONCLUDED.
> + error_setg(errp, "unimplemented");
This should hopefully go away when you reorder the patches.
> + block_job_do_dismiss(job);
> + *jobptr = NULL;
> +}
Kevin
- [Qemu-devel] [RFC v3 04/14] blockjobs: RFC add block_job_verb permission table, (continued)
[Qemu-devel] [RFC v3 05/14] blockjobs: add block_job_dismiss, John Snow, 2018/01/26
- Re: [Qemu-devel] [RFC v3 05/14] blockjobs: add block_job_dismiss,
Kevin Wolf <=
[Qemu-devel] [RFC v3 06/14] blockjobs: add CONCLUDED state, John Snow, 2018/01/26
[Qemu-devel] [RFC v3 07/14] blockjobs: ensure abort is called for cancelled jobs, John Snow, 2018/01/26
[Qemu-devel] [RFC v3 08/14] blockjobs: add commit, abort, clean helpers, John Snow, 2018/01/26
[Qemu-devel] [RFC v3 13/14] blockjobs: Expose manual property, John Snow, 2018/01/26
[Qemu-devel] [RFC v3 09/14] blockjobs: add prepare callback, John Snow, 2018/01/26
[Qemu-devel] [RFC v3 12/14] blockjobs: add block-job-finalize, John Snow, 2018/01/26
[Qemu-devel] [RFC v3 11/14] blockjobs: add PENDING status and event, John Snow, 2018/01/26
[Qemu-devel] [RFC v3 10/14] blockjobs: Add waiting event, John Snow, 2018/01/26
[Qemu-devel] [RFC v3 14/14] iotests: test manual job dismissal, John Snow, 2018/01/26