2 * Declarations for background jobs
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29 #include "qapi/qapi-types-job.h"
30 #include "qemu/queue.h"
31 #include "qemu/coroutine.h"
32 #include "block/aio.h"
34 typedef struct JobDriver JobDriver
;
35 typedef struct JobTxn JobTxn
;
39 * Long-running operation.
42 /** The ID of the job. May be NULL for internal jobs. */
45 /** The type of this job. */
46 const JobDriver
*driver
;
48 /** Reference count of the block job */
51 /** Current state; See @JobStatus for details. */
54 /** AioContext to run the job coroutine in */
55 AioContext
*aio_context
;
58 * The coroutine that executes the job. If not NULL, it is reentered when
59 * busy is false and the job is cancelled.
64 * Timer that is used by @job_sleep_ns. Accessed under job_mutex (in
67 QEMUTimer sleep_timer
;
70 * Counter for pause request. If non-zero, the block job is either paused,
71 * or if busy == true will pause itself as soon as possible.
76 * Set to false by the job while the coroutine has yielded and may be
77 * re-entered by job_enter(). There may still be I/O or event loop activity
78 * pending. Accessed under block_job_mutex (in blockjob.c).
80 * When the job is deferred to the main loop, busy is true as long as the
81 * bottom half is still pending.
86 * Set to true by the job while it is in a quiescent state, where
87 * no I/O or event loop activity is pending.
92 * Set to true if the job is paused by user. Can be unpaused with the
93 * block-job-resume QMP command.
98 * Set to true if the job should cancel itself. The flag must
99 * always be tested just before toggling the busy flag from false
100 * to true. After a job has been cancelled, it should only yield
101 * if #aio_poll will ("sooner or later") reenter the coroutine.
106 * Set to true if the job should abort immediately without waiting
107 * for data to be in sync.
111 /** Set to true when the job has deferred work to the main loop. */
112 bool deferred_to_main_loop
;
114 /** True if this job should automatically finalize itself */
117 /** True if this job should automatically dismiss itself */
121 * Current progress. The unit is arbitrary as long as the ratio between
122 * progress_current and progress_total represents the estimated percentage
123 * of work already done.
125 int64_t progress_current
;
127 /** Estimated progress_current value at the completion of the job */
128 int64_t progress_total
;
131 * Return code from @run and/or @prepare callback(s).
132 * Not final until the job has reached the CONCLUDED status.
133 * 0 on success, -errno on failure.
138 * Error object for a failed job.
139 * If job->ret is nonzero and an error object was not set, it will be set
140 * to strerror(-job->ret) during job_completed.
144 /** The completion function that will be called when the job completes. */
145 BlockCompletionFunc
*cb
;
147 /** The opaque value that is passed to the completion function. */
150 /** Notifiers called when a cancelled job is finalised */
151 NotifierList on_finalize_cancelled
;
153 /** Notifiers called when a successfully completed job is finalised */
154 NotifierList on_finalize_completed
;
156 /** Notifiers called when the job transitions to PENDING */
157 NotifierList on_pending
;
159 /** Notifiers called when the job transitions to READY */
160 NotifierList on_ready
;
162 /** Notifiers called when the job coroutine yields or terminates */
163 NotifierList on_idle
;
165 /** Element of the list of jobs */
166 QLIST_ENTRY(Job
) job_list
;
168 /** Transaction this job is part of */
171 /** Element of the list of jobs in a job transaction */
172 QLIST_ENTRY(Job
) txn_list
;
176 * Callbacks and other information about a Job driver.
179 /** Derived Job struct size */
180 size_t instance_size
;
182 /** Enum describing the operation */
186 * Mandatory: Entrypoint for the Coroutine.
188 * This callback will be invoked when moving from CREATED to RUNNING.
190 * If this callback returns nonzero, the job transaction it is part of is
191 * aborted. If it returns zero, the job moves into the WAITING state. If it
192 * is the last job to complete in its transaction, all jobs in the
193 * transaction move from WAITING to PENDING.
195 int coroutine_fn (*run
)(Job
*job
, Error
**errp
);
198 * If the callback is not NULL, it will be invoked when the job transitions
199 * into the paused state. Paused jobs must not perform any asynchronous
200 * I/O or event loop activity. This callback is used to quiesce jobs.
202 void coroutine_fn (*pause
)(Job
*job
);
205 * If the callback is not NULL, it will be invoked when the job transitions
206 * out of the paused state. Any asynchronous I/O or event loop activity
207 * should be restarted from this callback.
209 void coroutine_fn (*resume
)(Job
*job
);
212 * Called when the job is resumed by the user (i.e. user_paused becomes
213 * false). .user_resume is called before .resume.
215 void (*user_resume
)(Job
*job
);
218 * Optional callback for job types whose completion must be triggered
221 void (*complete
)(Job
*job
, Error
**errp
);
224 * If the callback is not NULL, prepare will be invoked when all the jobs
225 * belonging to the same transaction complete; or upon this job's completion
226 * if it is not in a transaction.
228 * This callback will not be invoked if the job has already failed.
229 * If it fails, abort and then clean will be called.
231 int (*prepare
)(Job
*job
);
234 * If the callback is not NULL, it will be invoked when all the jobs
235 * belonging to the same transaction complete; or upon this job's
236 * completion if it is not in a transaction. Skipped if NULL.
238 * All jobs will complete with a call to either .commit() or .abort() but
241 void (*commit
)(Job
*job
);
244 * If the callback is not NULL, it will be invoked when any job in the
245 * same transaction fails; or upon this job's failure (due to error or
246 * cancellation) if it is not in a transaction. Skipped if NULL.
248 * All jobs will complete with a call to either .commit() or .abort() but
251 void (*abort
)(Job
*job
);
254 * If the callback is not NULL, it will be invoked after a call to either
255 * .commit() or .abort(). Regardless of which callback is invoked after
256 * completion, .clean() will always be called, even if the job does not
257 * belong to a transaction group.
259 void (*clean
)(Job
*job
);
262 /** Called when the job is freed */
263 void (*free
)(Job
*job
);
266 typedef enum JobCreateFlags
{
267 /* Default behavior */
269 /* Job is not QMP-created and should not send QMP events */
271 /* Job requires manual finalize step */
272 JOB_MANUAL_FINALIZE
= 0x02,
273 /* Job requires manual dismiss step */
274 JOB_MANUAL_DISMISS
= 0x04,
278 * Allocate and return a new job transaction. Jobs can be added to the
279 * transaction using job_txn_add_job().
281 * The transaction is automatically freed when the last job completes or is
284 * All jobs in the transaction either complete successfully or fail/cancel as a
285 * group. Jobs wait for each other before completing. Cancelling one job
286 * cancels all jobs in the transaction.
288 JobTxn
*job_txn_new(void);
291 * Release a reference that was previously acquired with job_txn_add_job or
292 * job_txn_new. If it's the last reference to the object, it will be freed.
294 void job_txn_unref(JobTxn
*txn
);
297 * @txn: The transaction (may be NULL)
298 * @job: Job to add to the transaction
300 * Add @job to the transaction. The @job must not already be in a transaction.
301 * The caller must call either job_txn_unref() or job_completed() to release
302 * the reference that is automatically grabbed here.
304 * If @txn is NULL, the function does nothing.
306 void job_txn_add_job(JobTxn
*txn
, Job
*job
);
309 * Create a new long-running job and return it.
311 * @job_id: The id of the newly-created job, or %NULL for internal jobs
312 * @driver: The class object for the newly-created job.
313 * @txn: The transaction this job belongs to, if any. %NULL otherwise.
314 * @ctx: The AioContext to run the job coroutine in.
315 * @flags: Creation flags for the job. See @JobCreateFlags.
316 * @cb: Completion function for the job.
317 * @opaque: Opaque pointer value passed to @cb.
318 * @errp: Error object.
320 void *job_create(const char *job_id
, const JobDriver
*driver
, JobTxn
*txn
,
321 AioContext
*ctx
, int flags
, BlockCompletionFunc
*cb
,
322 void *opaque
, Error
**errp
);
325 * Add a reference to Job refcnt, it will be decreased with job_unref, and then
326 * be freed if it comes to be the last reference.
328 void job_ref(Job
*job
);
331 * Release a reference that was previously acquired with job_ref() or
332 * job_create(). If it's the last reference to the object, it will be freed.
334 void job_unref(Job
*job
);
337 * @job: The job that has made progress
338 * @done: How much progress the job made since the last call
340 * Updates the progress counter of the job.
342 void job_progress_update(Job
*job
, uint64_t done
);
345 * @job: The job whose expected progress end value is set
346 * @remaining: Missing progress (on top of the current progress counter value)
347 * until the new expected end value is reached
349 * Sets the expected end value of the progress counter of a job so that a
350 * completion percentage can be calculated when the progress is updated.
352 void job_progress_set_remaining(Job
*job
, uint64_t remaining
);
355 * @job: The job whose expected progress end value is updated
356 * @delta: Value which is to be added to the current expected end
359 * Increases the expected end value of the progress counter of a job.
360 * This is useful for parenthesis operations: If a job has to
361 * conditionally perform a high-priority operation as part of its
362 * progress, it calls this function with the expected operation's
363 * length before, and job_progress_update() afterwards.
364 * (So the operation acts as a parenthesis in regards to the main job
365 * operation running in background.)
367 void job_progress_increase_remaining(Job
*job
, uint64_t delta
);
369 /** To be called when a cancelled job is finalised. */
370 void job_event_cancelled(Job
*job
);
372 /** To be called when a successfully completed job is finalised. */
373 void job_event_completed(Job
*job
);
376 * Conditionally enter the job coroutine if the job is ready to run, not
377 * already busy and fn() returns true. fn() is called while under the job_lock
380 void job_enter_cond(Job
*job
, bool(*fn
)(Job
*job
));
383 * @job: A job that has not yet been started.
385 * Begins execution of a job.
386 * Takes ownership of one reference to the job object.
388 void job_start(Job
*job
);
391 * @job: The job to enter.
393 * Continue the specified job by entering the coroutine.
395 void job_enter(Job
*job
);
398 * @job: The job that is ready to pause.
400 * Pause now if job_pause() has been called. Jobs that perform lots of I/O
401 * must call this between requests so that the job can be paused.
403 void coroutine_fn
job_pause_point(Job
*job
);
406 * @job: The job that calls the function.
408 * Yield the job coroutine.
410 void job_yield(Job
*job
);
413 * @job: The job that calls the function.
414 * @ns: How many nanoseconds to stop for.
416 * Put the job to sleep (assuming that it wasn't canceled) for @ns
417 * %QEMU_CLOCK_REALTIME nanoseconds. Canceling the job will immediately
418 * interrupt the wait.
420 void coroutine_fn
job_sleep_ns(Job
*job
, int64_t ns
);
423 /** Returns the JobType of a given Job. */
424 JobType
job_type(const Job
*job
);
426 /** Returns the enum string for the JobType of a given Job. */
427 const char *job_type_str(const Job
*job
);
429 /** Returns true if the job should not be visible to the management layer. */
430 bool job_is_internal(Job
*job
);
432 /** Returns whether the job is scheduled for cancellation. */
433 bool job_is_cancelled(Job
*job
);
435 /** Returns whether the job is in a completed state. */
436 bool job_is_completed(Job
*job
);
438 /** Returns whether the job is ready to be completed. */
439 bool job_is_ready(Job
*job
);
442 * Request @job to pause at the next pause point. Must be paired with
443 * job_resume(). If the job is supposed to be resumed by user action, call
444 * job_user_pause() instead.
446 void job_pause(Job
*job
);
448 /** Resumes a @job paused with job_pause. */
449 void job_resume(Job
*job
);
452 * Asynchronously pause the specified @job.
453 * Do not allow a resume until a matching call to job_user_resume.
455 void job_user_pause(Job
*job
, Error
**errp
);
457 /** Returns true if the job is user-paused. */
458 bool job_user_paused(Job
*job
);
461 * Resume the specified @job.
462 * Must be paired with a preceding job_user_pause.
464 void job_user_resume(Job
*job
, Error
**errp
);
467 * Get the next element from the list of block jobs after @job, or the
468 * first one if @job is %NULL.
470 * Returns the requested job, or %NULL if there are no more jobs left.
472 Job
*job_next(Job
*job
);
475 * Get the job identified by @id (which must not be %NULL).
477 * Returns the requested job, or %NULL if it doesn't exist.
479 Job
*job_get(const char *id
);
482 * Check whether the verb @verb can be applied to @job in its current state.
483 * Returns 0 if the verb can be applied; otherwise errp is set and -EPERM
486 int job_apply_verb(Job
*job
, JobVerb verb
, Error
**errp
);
488 /** The @job could not be started, free it. */
489 void job_early_fail(Job
*job
);
491 /** Moves the @job from RUNNING to READY */
492 void job_transition_to_ready(Job
*job
);
494 /** Asynchronously complete the specified @job. */
495 void job_complete(Job
*job
, Error
**errp
);
498 * Asynchronously cancel the specified @job. If @force is true, the job should
499 * be cancelled immediately without waiting for a consistent state.
501 void job_cancel(Job
*job
, bool force
);
504 * Cancels the specified job like job_cancel(), but may refuse to do so if the
505 * operation isn't meaningful in the current state of the job.
507 void job_user_cancel(Job
*job
, bool force
, Error
**errp
);
510 * Synchronously cancel the @job. The completion callback is called
511 * before the function returns. The job may actually complete
512 * instead of canceling itself; the circumstances under which this
513 * happens depend on the kind of job that is active.
515 * Returns the return value from the job if the job actually completed
516 * during the call, or -ECANCELED if it was canceled.
518 * Callers must hold the AioContext lock of job->aio_context.
520 int job_cancel_sync(Job
*job
);
522 /** Synchronously cancels all jobs using job_cancel_sync(). */
523 void job_cancel_sync_all(void);
526 * @job: The job to be completed.
527 * @errp: Error object which may be set by job_complete(); this is not
528 * necessarily set on every error, the job return value has to be
531 * Synchronously complete the job. The completion callback is called before the
532 * function returns, unless it is NULL (which is permissible when using this
535 * Returns the return value from the job.
537 * Callers must hold the AioContext lock of job->aio_context.
539 int job_complete_sync(Job
*job
, Error
**errp
);
542 * For a @job that has finished its work and is pending awaiting explicit
543 * acknowledgement to commit its work, this will commit that work.
545 * FIXME: Make the below statement universally true:
546 * For jobs that support the manual workflow mode, all graph changes that occur
547 * as a result will occur after this command and before a successful reply.
549 void job_finalize(Job
*job
, Error
**errp
);
552 * Remove the concluded @job from the query list and resets the passed pointer
553 * to %NULL. Returns an error if the job is not actually concluded.
555 void job_dismiss(Job
**job
, Error
**errp
);
558 * Synchronously finishes the given @job. If @finish is given, it is called to
559 * trigger completion or cancellation of the job.
561 * Returns 0 if the job is successfully completed, -ECANCELED if the job was
562 * cancelled before completing, and -errno in other error cases.
564 * Callers must hold the AioContext lock of job->aio_context.
566 int job_finish_sync(Job
*job
, void (*finish
)(Job
*, Error
**errp
), Error
**errp
);