2 * Declarations for background jobs
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29 #include "qapi/qapi-types-job.h"
30 #include "qemu/queue.h"
31 #include "qemu/progress_meter.h"
32 #include "qemu/coroutine.h"
33 #include "block/aio.h"
35 typedef struct JobDriver JobDriver
;
36 typedef struct JobTxn JobTxn
;
40 * Long-running operation.
43 /** The ID of the job. May be NULL for internal jobs. */
46 /** The type of this job. */
47 const JobDriver
*driver
;
49 /** Reference count of the block job */
52 /** Current state; See @JobStatus for details. */
55 /** AioContext to run the job coroutine in */
56 AioContext
*aio_context
;
59 * The coroutine that executes the job. If not NULL, it is reentered when
60 * busy is false and the job is cancelled.
65 * Timer that is used by @job_sleep_ns. Accessed under job_mutex (in
68 QEMUTimer sleep_timer
;
71 * Counter for pause request. If non-zero, the block job is either paused,
72 * or if busy == true will pause itself as soon as possible.
77 * Set to false by the job while the coroutine has yielded and may be
78 * re-entered by job_enter(). There may still be I/O or event loop activity
79 * pending. Accessed under block_job_mutex (in blockjob.c).
81 * When the job is deferred to the main loop, busy is true as long as the
82 * bottom half is still pending.
87 * Set to true by the job while it is in a quiescent state, where
88 * no I/O or event loop activity is pending.
93 * Set to true if the job is paused by user. Can be unpaused with the
94 * block-job-resume QMP command.
99 * Set to true if the job should cancel itself. The flag must
100 * always be tested just before toggling the busy flag from false
101 * to true. After a job has been cancelled, it should only yield
102 * if #aio_poll will ("sooner or later") reenter the coroutine.
107 * Set to true if the job should abort immediately without waiting
108 * for data to be in sync.
112 /** Set to true when the job has deferred work to the main loop. */
113 bool deferred_to_main_loop
;
115 /** True if this job should automatically finalize itself */
118 /** True if this job should automatically dismiss itself */
121 ProgressMeter progress
;
124 * Return code from @run and/or @prepare callback(s).
125 * Not final until the job has reached the CONCLUDED status.
126 * 0 on success, -errno on failure.
131 * Error object for a failed job.
132 * If job->ret is nonzero and an error object was not set, it will be set
133 * to strerror(-job->ret) during job_completed.
137 /** The completion function that will be called when the job completes. */
138 BlockCompletionFunc
*cb
;
140 /** The opaque value that is passed to the completion function. */
143 /** Notifiers called when a cancelled job is finalised */
144 NotifierList on_finalize_cancelled
;
146 /** Notifiers called when a successfully completed job is finalised */
147 NotifierList on_finalize_completed
;
149 /** Notifiers called when the job transitions to PENDING */
150 NotifierList on_pending
;
152 /** Notifiers called when the job transitions to READY */
153 NotifierList on_ready
;
155 /** Notifiers called when the job coroutine yields or terminates */
156 NotifierList on_idle
;
158 /** Element of the list of jobs */
159 QLIST_ENTRY(Job
) job_list
;
161 /** Transaction this job is part of */
164 /** Element of the list of jobs in a job transaction */
165 QLIST_ENTRY(Job
) txn_list
;
169 * Callbacks and other information about a Job driver.
172 /** Derived Job struct size */
173 size_t instance_size
;
175 /** Enum describing the operation */
179 * Mandatory: Entrypoint for the Coroutine.
181 * This callback will be invoked when moving from CREATED to RUNNING.
183 * If this callback returns nonzero, the job transaction it is part of is
184 * aborted. If it returns zero, the job moves into the WAITING state. If it
185 * is the last job to complete in its transaction, all jobs in the
186 * transaction move from WAITING to PENDING.
188 int coroutine_fn (*run
)(Job
*job
, Error
**errp
);
191 * If the callback is not NULL, it will be invoked when the job transitions
192 * into the paused state. Paused jobs must not perform any asynchronous
193 * I/O or event loop activity. This callback is used to quiesce jobs.
195 void coroutine_fn (*pause
)(Job
*job
);
198 * If the callback is not NULL, it will be invoked when the job transitions
199 * out of the paused state. Any asynchronous I/O or event loop activity
200 * should be restarted from this callback.
202 void coroutine_fn (*resume
)(Job
*job
);
205 * Called when the job is resumed by the user (i.e. user_paused becomes
206 * false). .user_resume is called before .resume.
208 void (*user_resume
)(Job
*job
);
211 * Optional callback for job types whose completion must be triggered
214 void (*complete
)(Job
*job
, Error
**errp
);
217 * If the callback is not NULL, prepare will be invoked when all the jobs
218 * belonging to the same transaction complete; or upon this job's completion
219 * if it is not in a transaction.
221 * This callback will not be invoked if the job has already failed.
222 * If it fails, abort and then clean will be called.
224 int (*prepare
)(Job
*job
);
227 * If the callback is not NULL, it will be invoked when all the jobs
228 * belonging to the same transaction complete; or upon this job's
229 * completion if it is not in a transaction. Skipped if NULL.
231 * All jobs will complete with a call to either .commit() or .abort() but
234 void (*commit
)(Job
*job
);
237 * If the callback is not NULL, it will be invoked when any job in the
238 * same transaction fails; or upon this job's failure (due to error or
239 * cancellation) if it is not in a transaction. Skipped if NULL.
241 * All jobs will complete with a call to either .commit() or .abort() but
244 void (*abort
)(Job
*job
);
247 * If the callback is not NULL, it will be invoked after a call to either
248 * .commit() or .abort(). Regardless of which callback is invoked after
249 * completion, .clean() will always be called, even if the job does not
250 * belong to a transaction group.
252 void (*clean
)(Job
*job
);
255 /** Called when the job is freed */
256 void (*free
)(Job
*job
);
259 typedef enum JobCreateFlags
{
260 /* Default behavior */
262 /* Job is not QMP-created and should not send QMP events */
264 /* Job requires manual finalize step */
265 JOB_MANUAL_FINALIZE
= 0x02,
266 /* Job requires manual dismiss step */
267 JOB_MANUAL_DISMISS
= 0x04,
271 * Allocate and return a new job transaction. Jobs can be added to the
272 * transaction using job_txn_add_job().
274 * The transaction is automatically freed when the last job completes or is
277 * All jobs in the transaction either complete successfully or fail/cancel as a
278 * group. Jobs wait for each other before completing. Cancelling one job
279 * cancels all jobs in the transaction.
281 JobTxn
*job_txn_new(void);
284 * Release a reference that was previously acquired with job_txn_add_job or
285 * job_txn_new. If it's the last reference to the object, it will be freed.
287 void job_txn_unref(JobTxn
*txn
);
290 * @txn: The transaction (may be NULL)
291 * @job: Job to add to the transaction
293 * Add @job to the transaction. The @job must not already be in a transaction.
294 * The caller must call either job_txn_unref() or job_completed() to release
295 * the reference that is automatically grabbed here.
297 * If @txn is NULL, the function does nothing.
299 void job_txn_add_job(JobTxn
*txn
, Job
*job
);
302 * Create a new long-running job and return it.
304 * @job_id: The id of the newly-created job, or %NULL for internal jobs
305 * @driver: The class object for the newly-created job.
306 * @txn: The transaction this job belongs to, if any. %NULL otherwise.
307 * @ctx: The AioContext to run the job coroutine in.
308 * @flags: Creation flags for the job. See @JobCreateFlags.
309 * @cb: Completion function for the job.
310 * @opaque: Opaque pointer value passed to @cb.
311 * @errp: Error object.
313 void *job_create(const char *job_id
, const JobDriver
*driver
, JobTxn
*txn
,
314 AioContext
*ctx
, int flags
, BlockCompletionFunc
*cb
,
315 void *opaque
, Error
**errp
);
318 * Add a reference to Job refcnt, it will be decreased with job_unref, and then
319 * be freed if it comes to be the last reference.
321 void job_ref(Job
*job
);
324 * Release a reference that was previously acquired with job_ref() or
325 * job_create(). If it's the last reference to the object, it will be freed.
327 void job_unref(Job
*job
);
330 * @job: The job that has made progress
331 * @done: How much progress the job made since the last call
333 * Updates the progress counter of the job.
335 void job_progress_update(Job
*job
, uint64_t done
);
338 * @job: The job whose expected progress end value is set
339 * @remaining: Missing progress (on top of the current progress counter value)
340 * until the new expected end value is reached
342 * Sets the expected end value of the progress counter of a job so that a
343 * completion percentage can be calculated when the progress is updated.
345 void job_progress_set_remaining(Job
*job
, uint64_t remaining
);
348 * @job: The job whose expected progress end value is updated
349 * @delta: Value which is to be added to the current expected end
352 * Increases the expected end value of the progress counter of a job.
353 * This is useful for parenthesis operations: If a job has to
354 * conditionally perform a high-priority operation as part of its
355 * progress, it calls this function with the expected operation's
356 * length before, and job_progress_update() afterwards.
357 * (So the operation acts as a parenthesis in regards to the main job
358 * operation running in background.)
360 void job_progress_increase_remaining(Job
*job
, uint64_t delta
);
362 /** To be called when a cancelled job is finalised. */
363 void job_event_cancelled(Job
*job
);
365 /** To be called when a successfully completed job is finalised. */
366 void job_event_completed(Job
*job
);
369 * Conditionally enter the job coroutine if the job is ready to run, not
370 * already busy and fn() returns true. fn() is called while under the job_lock
373 void job_enter_cond(Job
*job
, bool(*fn
)(Job
*job
));
376 * @job: A job that has not yet been started.
378 * Begins execution of a job.
379 * Takes ownership of one reference to the job object.
381 void job_start(Job
*job
);
384 * @job: The job to enter.
386 * Continue the specified job by entering the coroutine.
388 void job_enter(Job
*job
);
391 * @job: The job that is ready to pause.
393 * Pause now if job_pause() has been called. Jobs that perform lots of I/O
394 * must call this between requests so that the job can be paused.
396 void coroutine_fn
job_pause_point(Job
*job
);
399 * @job: The job that calls the function.
401 * Yield the job coroutine.
403 void job_yield(Job
*job
);
406 * @job: The job that calls the function.
407 * @ns: How many nanoseconds to stop for.
409 * Put the job to sleep (assuming that it wasn't canceled) for @ns
410 * %QEMU_CLOCK_REALTIME nanoseconds. Canceling the job will immediately
411 * interrupt the wait.
413 void coroutine_fn
job_sleep_ns(Job
*job
, int64_t ns
);
416 /** Returns the JobType of a given Job. */
417 JobType
job_type(const Job
*job
);
419 /** Returns the enum string for the JobType of a given Job. */
420 const char *job_type_str(const Job
*job
);
422 /** Returns true if the job should not be visible to the management layer. */
423 bool job_is_internal(Job
*job
);
425 /** Returns whether the job is scheduled for cancellation. */
426 bool job_is_cancelled(Job
*job
);
428 /** Returns whether the job is in a completed state. */
429 bool job_is_completed(Job
*job
);
431 /** Returns whether the job is ready to be completed. */
432 bool job_is_ready(Job
*job
);
435 * Request @job to pause at the next pause point. Must be paired with
436 * job_resume(). If the job is supposed to be resumed by user action, call
437 * job_user_pause() instead.
439 void job_pause(Job
*job
);
441 /** Resumes a @job paused with job_pause. */
442 void job_resume(Job
*job
);
445 * Asynchronously pause the specified @job.
446 * Do not allow a resume until a matching call to job_user_resume.
448 void job_user_pause(Job
*job
, Error
**errp
);
450 /** Returns true if the job is user-paused. */
451 bool job_user_paused(Job
*job
);
454 * Resume the specified @job.
455 * Must be paired with a preceding job_user_pause.
457 void job_user_resume(Job
*job
, Error
**errp
);
460 * Get the next element from the list of block jobs after @job, or the
461 * first one if @job is %NULL.
463 * Returns the requested job, or %NULL if there are no more jobs left.
465 Job
*job_next(Job
*job
);
468 * Get the job identified by @id (which must not be %NULL).
470 * Returns the requested job, or %NULL if it doesn't exist.
472 Job
*job_get(const char *id
);
475 * Check whether the verb @verb can be applied to @job in its current state.
476 * Returns 0 if the verb can be applied; otherwise errp is set and -EPERM
479 int job_apply_verb(Job
*job
, JobVerb verb
, Error
**errp
);
481 /** The @job could not be started, free it. */
482 void job_early_fail(Job
*job
);
484 /** Moves the @job from RUNNING to READY */
485 void job_transition_to_ready(Job
*job
);
487 /** Asynchronously complete the specified @job. */
488 void job_complete(Job
*job
, Error
**errp
);
491 * Asynchronously cancel the specified @job. If @force is true, the job should
492 * be cancelled immediately without waiting for a consistent state.
494 void job_cancel(Job
*job
, bool force
);
497 * Cancels the specified job like job_cancel(), but may refuse to do so if the
498 * operation isn't meaningful in the current state of the job.
500 void job_user_cancel(Job
*job
, bool force
, Error
**errp
);
503 * Synchronously cancel the @job. The completion callback is called
504 * before the function returns. The job may actually complete
505 * instead of canceling itself; the circumstances under which this
506 * happens depend on the kind of job that is active.
508 * Returns the return value from the job if the job actually completed
509 * during the call, or -ECANCELED if it was canceled.
511 * Callers must hold the AioContext lock of job->aio_context.
513 int job_cancel_sync(Job
*job
);
515 /** Synchronously cancels all jobs using job_cancel_sync(). */
516 void job_cancel_sync_all(void);
519 * @job: The job to be completed.
520 * @errp: Error object which may be set by job_complete(); this is not
521 * necessarily set on every error, the job return value has to be
524 * Synchronously complete the job. The completion callback is called before the
525 * function returns, unless it is NULL (which is permissible when using this
528 * Returns the return value from the job.
530 * Callers must hold the AioContext lock of job->aio_context.
532 int job_complete_sync(Job
*job
, Error
**errp
);
535 * For a @job that has finished its work and is pending awaiting explicit
536 * acknowledgement to commit its work, this will commit that work.
538 * FIXME: Make the below statement universally true:
539 * For jobs that support the manual workflow mode, all graph changes that occur
540 * as a result will occur after this command and before a successful reply.
542 void job_finalize(Job
*job
, Error
**errp
);
545 * Remove the concluded @job from the query list and resets the passed pointer
546 * to %NULL. Returns an error if the job is not actually concluded.
548 void job_dismiss(Job
**job
, Error
**errp
);
551 * Synchronously finishes the given @job. If @finish is given, it is called to
552 * trigger completion or cancellation of the job.
554 * Returns 0 if the job is successfully completed, -ECANCELED if the job was
555 * cancelled before completing, and -errno in other error cases.
557 * Callers must hold the AioContext lock of job->aio_context.
559 int job_finish_sync(Job
*job
, void (*finish
)(Job
*, Error
**errp
), Error
**errp
);