2 * Declarations for background jobs
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29 #include "qapi/qapi-types-block-core.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).
83 * Set to true by the job while it is in a quiescent state, where
84 * no I/O or event loop activity is pending.
89 * Set to true if the job is paused by user. Can be unpaused with the
90 * block-job-resume QMP command.
95 * Set to true if the job should cancel itself. The flag must
96 * always be tested just before toggling the busy flag from false
97 * to true. After a job has been cancelled, it should only yield
98 * if #aio_poll will ("sooner or later") reenter the coroutine.
103 * Set to true if the job should abort immediately without waiting
104 * for data to be in sync.
108 /** Set to true when the job has deferred work to the main loop. */
109 bool deferred_to_main_loop
;
111 /** True if this job should automatically finalize itself */
114 /** True if this job should automatically dismiss itself */
117 /** ret code passed to job_completed. */
120 /** The completion function that will be called when the job completes. */
121 BlockCompletionFunc
*cb
;
123 /** The opaque value that is passed to the completion function. */
126 /** Notifiers called when a cancelled job is finalised */
127 NotifierList on_finalize_cancelled
;
129 /** Notifiers called when a successfully completed job is finalised */
130 NotifierList on_finalize_completed
;
132 /** Notifiers called when the job transitions to PENDING */
133 NotifierList on_pending
;
135 /** Element of the list of jobs */
136 QLIST_ENTRY(Job
) job_list
;
138 /** Transaction this job is part of */
141 /** Element of the list of jobs in a job transaction */
142 QLIST_ENTRY(Job
) txn_list
;
146 * Callbacks and other information about a Job driver.
149 /** Derived Job struct size */
150 size_t instance_size
;
152 /** Enum describing the operation */
155 /** Mandatory: Entrypoint for the Coroutine. */
156 CoroutineEntry
*start
;
159 * If the callback is not NULL, it will be invoked when the job transitions
160 * into the paused state. Paused jobs must not perform any asynchronous
161 * I/O or event loop activity. This callback is used to quiesce jobs.
163 void coroutine_fn (*pause
)(Job
*job
);
166 * If the callback is not NULL, it will be invoked when the job transitions
167 * out of the paused state. Any asynchronous I/O or event loop activity
168 * should be restarted from this callback.
170 void coroutine_fn (*resume
)(Job
*job
);
173 * Called when the job is resumed by the user (i.e. user_paused becomes
174 * false). .user_resume is called before .resume.
176 void (*user_resume
)(Job
*job
);
179 * Optional callback for job types whose completion must be triggered
182 void (*complete
)(Job
*job
, Error
**errp
);
185 * If the callback is not NULL, it will be invoked when the job has to be
186 * synchronously cancelled or completed; it should drain any activities
187 * as required to ensure progress.
189 void (*drain
)(Job
*job
);
192 * If the callback is not NULL, prepare will be invoked when all the jobs
193 * belonging to the same transaction complete; or upon this job's completion
194 * if it is not in a transaction.
196 * This callback will not be invoked if the job has already failed.
197 * If it fails, abort and then clean will be called.
199 int (*prepare
)(Job
*job
);
202 * If the callback is not NULL, it will be invoked when all the jobs
203 * belonging to the same transaction complete; or upon this job's
204 * completion if it is not in a transaction. Skipped if NULL.
206 * All jobs will complete with a call to either .commit() or .abort() but
209 void (*commit
)(Job
*job
);
212 * If the callback is not NULL, it will be invoked when any job in the
213 * same transaction fails; or upon this job's failure (due to error or
214 * cancellation) if it is not in a transaction. Skipped if NULL.
216 * All jobs will complete with a call to either .commit() or .abort() but
219 void (*abort
)(Job
*job
);
222 * If the callback is not NULL, it will be invoked after a call to either
223 * .commit() or .abort(). Regardless of which callback is invoked after
224 * completion, .clean() will always be called, even if the job does not
225 * belong to a transaction group.
227 void (*clean
)(Job
*job
);
230 /** Called when the job is freed */
231 void (*free
)(Job
*job
);
234 typedef enum JobCreateFlags
{
235 /* Default behavior */
237 /* Job is not QMP-created and should not send QMP events */
239 /* Job requires manual finalize step */
240 JOB_MANUAL_FINALIZE
= 0x02,
241 /* Job requires manual dismiss step */
242 JOB_MANUAL_DISMISS
= 0x04,
246 * Allocate and return a new job transaction. Jobs can be added to the
247 * transaction using job_txn_add_job().
249 * The transaction is automatically freed when the last job completes or is
252 * All jobs in the transaction either complete successfully or fail/cancel as a
253 * group. Jobs wait for each other before completing. Cancelling one job
254 * cancels all jobs in the transaction.
256 JobTxn
*job_txn_new(void);
259 * Release a reference that was previously acquired with job_txn_add_job or
260 * job_txn_new. If it's the last reference to the object, it will be freed.
262 void job_txn_unref(JobTxn
*txn
);
265 * @txn: The transaction (may be NULL)
266 * @job: Job to add to the transaction
268 * Add @job to the transaction. The @job must not already be in a transaction.
269 * The caller must call either job_txn_unref() or job_completed() to release
270 * the reference that is automatically grabbed here.
272 * If @txn is NULL, the function does nothing.
274 void job_txn_add_job(JobTxn
*txn
, Job
*job
);
277 * Create a new long-running job and return it.
279 * @job_id: The id of the newly-created job, or %NULL for internal jobs
280 * @driver: The class object for the newly-created job.
281 * @txn: The transaction this job belongs to, if any. %NULL otherwise.
282 * @ctx: The AioContext to run the job coroutine in.
283 * @flags: Creation flags for the job. See @JobCreateFlags.
284 * @cb: Completion function for the job.
285 * @opaque: Opaque pointer value passed to @cb.
286 * @errp: Error object.
288 void *job_create(const char *job_id
, const JobDriver
*driver
, JobTxn
*txn
,
289 AioContext
*ctx
, int flags
, BlockCompletionFunc
*cb
,
290 void *opaque
, Error
**errp
);
293 * Add a reference to Job refcnt, it will be decreased with job_unref, and then
294 * be freed if it comes to be the last reference.
296 void job_ref(Job
*job
);
299 * Release a reference that was previously acquired with job_ref() or
300 * job_create(). If it's the last reference to the object, it will be freed.
302 void job_unref(Job
*job
);
304 /** To be called when a cancelled job is finalised. */
305 void job_event_cancelled(Job
*job
);
307 /** To be called when a successfully completed job is finalised. */
308 void job_event_completed(Job
*job
);
311 * Conditionally enter the job coroutine if the job is ready to run, not
312 * already busy and fn() returns true. fn() is called while under the job_lock
315 void job_enter_cond(Job
*job
, bool(*fn
)(Job
*job
));
318 * @job: A job that has not yet been started.
320 * Begins execution of a job.
321 * Takes ownership of one reference to the job object.
323 void job_start(Job
*job
);
326 * @job: The job to enter.
328 * Continue the specified job by entering the coroutine.
330 void job_enter(Job
*job
);
333 * @job: The job that is ready to pause.
335 * Pause now if job_pause() has been called. Jobs that perform lots of I/O
336 * must call this between requests so that the job can be paused.
338 void coroutine_fn
job_pause_point(Job
*job
);
341 * @job: The job that calls the function.
343 * Yield the job coroutine.
345 void job_yield(Job
*job
);
348 * @job: The job that calls the function.
349 * @ns: How many nanoseconds to stop for.
351 * Put the job to sleep (assuming that it wasn't canceled) for @ns
352 * %QEMU_CLOCK_REALTIME nanoseconds. Canceling the job will immediately
353 * interrupt the wait.
355 void coroutine_fn
job_sleep_ns(Job
*job
, int64_t ns
);
358 /** Returns the JobType of a given Job. */
359 JobType
job_type(const Job
*job
);
361 /** Returns the enum string for the JobType of a given Job. */
362 const char *job_type_str(const Job
*job
);
364 /** Returns whether the job is scheduled for cancellation. */
365 bool job_is_cancelled(Job
*job
);
367 /** Returns whether the job is in a completed state. */
368 bool job_is_completed(Job
*job
);
370 /** Returns whether the job is ready to be completed. */
371 bool job_is_ready(Job
*job
);
374 * Request @job to pause at the next pause point. Must be paired with
375 * job_resume(). If the job is supposed to be resumed by user action, call
376 * job_user_pause() instead.
378 void job_pause(Job
*job
);
380 /** Resumes a @job paused with job_pause. */
381 void job_resume(Job
*job
);
384 * Asynchronously pause the specified @job.
385 * Do not allow a resume until a matching call to job_user_resume.
387 void job_user_pause(Job
*job
, Error
**errp
);
389 /** Returns true if the job is user-paused. */
390 bool job_user_paused(Job
*job
);
393 * Resume the specified @job.
394 * Must be paired with a preceding job_user_pause.
396 void job_user_resume(Job
*job
, Error
**errp
);
399 * Drain any activities as required to ensure progress. This can be called in a
400 * loop to synchronously complete a job.
402 void job_drain(Job
*job
);
405 * Get the next element from the list of block jobs after @job, or the
406 * first one if @job is %NULL.
408 * Returns the requested job, or %NULL if there are no more jobs left.
410 Job
*job_next(Job
*job
);
413 * Get the job identified by @id (which must not be %NULL).
415 * Returns the requested job, or %NULL if it doesn't exist.
417 Job
*job_get(const char *id
);
420 * Check whether the verb @verb can be applied to @job in its current state.
421 * Returns 0 if the verb can be applied; otherwise errp is set and -EPERM
424 int job_apply_verb(Job
*job
, JobVerb verb
, Error
**errp
);
426 /** The @job could not be started, free it. */
427 void job_early_fail(Job
*job
);
430 * @job: The job being completed.
431 * @ret: The status code.
433 * Marks @job as completed. If @ret is non-zero, the job transaction it is part
434 * of is aborted. If @ret is zero, the job moves into the WAITING state. If it
435 * is the last job to complete in its transaction, all jobs in the transaction
436 * move from WAITING to PENDING.
438 void job_completed(Job
*job
, int ret
);
440 /** Asynchronously complete the specified @job. */
441 void job_complete(Job
*job
, Error
**errp
);
444 * Asynchronously cancel the specified @job. If @force is true, the job should
445 * be cancelled immediately without waiting for a consistent state.
447 void job_cancel(Job
*job
, bool force
);
450 * Cancels the specified job like job_cancel(), but may refuse to do so if the
451 * operation isn't meaningful in the current state of the job.
453 void job_user_cancel(Job
*job
, bool force
, Error
**errp
);
456 * Synchronously cancel the @job. The completion callback is called
457 * before the function returns. The job may actually complete
458 * instead of canceling itself; the circumstances under which this
459 * happens depend on the kind of job that is active.
461 * Returns the return value from the job if the job actually completed
462 * during the call, or -ECANCELED if it was canceled.
464 int job_cancel_sync(Job
*job
);
466 /** Synchronously cancels all jobs using job_cancel_sync(). */
467 void job_cancel_sync_all(void);
470 * @job: The job to be completed.
471 * @errp: Error object which may be set by job_complete(); this is not
472 * necessarily set on every error, the job return value has to be
475 * Synchronously complete the job. The completion callback is called before the
476 * function returns, unless it is NULL (which is permissible when using this
479 * Returns the return value from the job.
481 int job_complete_sync(Job
*job
, Error
**errp
);
484 * For a @job that has finished its work and is pending awaiting explicit
485 * acknowledgement to commit its work, this will commit that work.
487 * FIXME: Make the below statement universally true:
488 * For jobs that support the manual workflow mode, all graph changes that occur
489 * as a result will occur after this command and before a successful reply.
491 void job_finalize(Job
*job
, Error
**errp
);
494 * Remove the concluded @job from the query list and resets the passed pointer
495 * to %NULL. Returns an error if the job is not actually concluded.
497 void job_dismiss(Job
**job
, Error
**errp
);
499 typedef void JobDeferToMainLoopFn(Job
*job
, void *opaque
);
503 * @fn: The function to run in the main loop
504 * @opaque: The opaque value that is passed to @fn
506 * This function must be called by the main job coroutine just before it
507 * returns. @fn is executed in the main loop with the job AioContext acquired.
509 * Block jobs must call bdrv_unref(), bdrv_close(), and anything that uses
510 * bdrv_drain_all() in the main loop.
512 * The @job AioContext is held while @fn executes.
514 void job_defer_to_main_loop(Job
*job
, JobDeferToMainLoopFn
*fn
, void *opaque
);
517 * Synchronously finishes the given @job. If @finish is given, it is called to
518 * trigger completion or cancellation of the job.
520 * Returns 0 if the job is successfully completed, -ECANCELED if the job was
521 * cancelled before completing, and -errno in other error cases.
523 int job_finish_sync(Job
*job
, void (*finish
)(Job
*, Error
**errp
), Error
**errp
);
525 /* TODO To be removed from the public interface */
526 void job_state_transition(Job
*job
, JobStatus s1
);