Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-and-misc-271020-1...
[qemu.git] / job.c
1 /*
2 * Background jobs (long-running operations)
3 *
4 * Copyright (c) 2011 IBM Corp.
5 * Copyright (c) 2012, 2018 Red Hat, Inc.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23 * THE SOFTWARE.
24 */
25
26 #include "qemu/osdep.h"
27 #include "qapi/error.h"
28 #include "qemu/job.h"
29 #include "qemu/id.h"
30 #include "qemu/main-loop.h"
31 #include "block/aio-wait.h"
32 #include "trace/trace-root.h"
33 #include "qapi/qapi-events-job.h"
34
35 static QLIST_HEAD(, Job) jobs = QLIST_HEAD_INITIALIZER(jobs);
36
37 /* Job State Transition Table */
38 bool JobSTT[JOB_STATUS__MAX][JOB_STATUS__MAX] = {
39 /* U, C, R, P, Y, S, W, D, X, E, N */
40 /* U: */ [JOB_STATUS_UNDEFINED] = {0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0},
41 /* C: */ [JOB_STATUS_CREATED] = {0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1},
42 /* R: */ [JOB_STATUS_RUNNING] = {0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0},
43 /* P: */ [JOB_STATUS_PAUSED] = {0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0},
44 /* Y: */ [JOB_STATUS_READY] = {0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0},
45 /* S: */ [JOB_STATUS_STANDBY] = {0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0},
46 /* W: */ [JOB_STATUS_WAITING] = {0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0},
47 /* D: */ [JOB_STATUS_PENDING] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0},
48 /* X: */ [JOB_STATUS_ABORTING] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0},
49 /* E: */ [JOB_STATUS_CONCLUDED] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
50 /* N: */ [JOB_STATUS_NULL] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
51 };
52
53 bool JobVerbTable[JOB_VERB__MAX][JOB_STATUS__MAX] = {
54 /* U, C, R, P, Y, S, W, D, X, E, N */
55 [JOB_VERB_CANCEL] = {0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0},
56 [JOB_VERB_PAUSE] = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
57 [JOB_VERB_RESUME] = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
58 [JOB_VERB_SET_SPEED] = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
59 [JOB_VERB_COMPLETE] = {0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0},
60 [JOB_VERB_FINALIZE] = {0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0},
61 [JOB_VERB_DISMISS] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0},
62 };
63
64 /* Transactional group of jobs */
65 struct JobTxn {
66
67 /* Is this txn being cancelled? */
68 bool aborting;
69
70 /* List of jobs */
71 QLIST_HEAD(, Job) jobs;
72
73 /* Reference count */
74 int refcnt;
75 };
76
77 /* Right now, this mutex is only needed to synchronize accesses to job->busy
78 * and job->sleep_timer, such as concurrent calls to job_do_yield and
79 * job_enter. */
80 static QemuMutex job_mutex;
81
82 static void job_lock(void)
83 {
84 qemu_mutex_lock(&job_mutex);
85 }
86
87 static void job_unlock(void)
88 {
89 qemu_mutex_unlock(&job_mutex);
90 }
91
92 static void __attribute__((__constructor__)) job_init(void)
93 {
94 qemu_mutex_init(&job_mutex);
95 }
96
97 JobTxn *job_txn_new(void)
98 {
99 JobTxn *txn = g_new0(JobTxn, 1);
100 QLIST_INIT(&txn->jobs);
101 txn->refcnt = 1;
102 return txn;
103 }
104
105 static void job_txn_ref(JobTxn *txn)
106 {
107 txn->refcnt++;
108 }
109
110 void job_txn_unref(JobTxn *txn)
111 {
112 if (txn && --txn->refcnt == 0) {
113 g_free(txn);
114 }
115 }
116
117 void job_txn_add_job(JobTxn *txn, Job *job)
118 {
119 if (!txn) {
120 return;
121 }
122
123 assert(!job->txn);
124 job->txn = txn;
125
126 QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
127 job_txn_ref(txn);
128 }
129
130 static void job_txn_del_job(Job *job)
131 {
132 if (job->txn) {
133 QLIST_REMOVE(job, txn_list);
134 job_txn_unref(job->txn);
135 job->txn = NULL;
136 }
137 }
138
139 static int job_txn_apply(Job *job, int fn(Job *))
140 {
141 AioContext *inner_ctx;
142 Job *other_job, *next;
143 JobTxn *txn = job->txn;
144 int rc = 0;
145
146 /*
147 * Similar to job_completed_txn_abort, we take each job's lock before
148 * applying fn, but since we assume that outer_ctx is held by the caller,
149 * we need to release it here to avoid holding the lock twice - which would
150 * break AIO_WAIT_WHILE from within fn.
151 */
152 job_ref(job);
153 aio_context_release(job->aio_context);
154
155 QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
156 inner_ctx = other_job->aio_context;
157 aio_context_acquire(inner_ctx);
158 rc = fn(other_job);
159 aio_context_release(inner_ctx);
160 if (rc) {
161 break;
162 }
163 }
164
165 /*
166 * Note that job->aio_context might have been changed by calling fn, so we
167 * can't use a local variable to cache it.
168 */
169 aio_context_acquire(job->aio_context);
170 job_unref(job);
171 return rc;
172 }
173
174 bool job_is_internal(Job *job)
175 {
176 return (job->id == NULL);
177 }
178
179 static void job_state_transition(Job *job, JobStatus s1)
180 {
181 JobStatus s0 = job->status;
182 assert(s1 >= 0 && s1 < JOB_STATUS__MAX);
183 trace_job_state_transition(job, job->ret,
184 JobSTT[s0][s1] ? "allowed" : "disallowed",
185 JobStatus_str(s0), JobStatus_str(s1));
186 assert(JobSTT[s0][s1]);
187 job->status = s1;
188
189 if (!job_is_internal(job) && s1 != s0) {
190 qapi_event_send_job_status_change(job->id, job->status);
191 }
192 }
193
194 int job_apply_verb(Job *job, JobVerb verb, Error **errp)
195 {
196 JobStatus s0 = job->status;
197 assert(verb >= 0 && verb < JOB_VERB__MAX);
198 trace_job_apply_verb(job, JobStatus_str(s0), JobVerb_str(verb),
199 JobVerbTable[verb][s0] ? "allowed" : "prohibited");
200 if (JobVerbTable[verb][s0]) {
201 return 0;
202 }
203 error_setg(errp, "Job '%s' in state '%s' cannot accept command verb '%s'",
204 job->id, JobStatus_str(s0), JobVerb_str(verb));
205 return -EPERM;
206 }
207
208 JobType job_type(const Job *job)
209 {
210 return job->driver->job_type;
211 }
212
213 const char *job_type_str(const Job *job)
214 {
215 return JobType_str(job_type(job));
216 }
217
218 bool job_is_cancelled(Job *job)
219 {
220 return job->cancelled;
221 }
222
223 bool job_is_ready(Job *job)
224 {
225 switch (job->status) {
226 case JOB_STATUS_UNDEFINED:
227 case JOB_STATUS_CREATED:
228 case JOB_STATUS_RUNNING:
229 case JOB_STATUS_PAUSED:
230 case JOB_STATUS_WAITING:
231 case JOB_STATUS_PENDING:
232 case JOB_STATUS_ABORTING:
233 case JOB_STATUS_CONCLUDED:
234 case JOB_STATUS_NULL:
235 return false;
236 case JOB_STATUS_READY:
237 case JOB_STATUS_STANDBY:
238 return true;
239 default:
240 g_assert_not_reached();
241 }
242 return false;
243 }
244
245 bool job_is_completed(Job *job)
246 {
247 switch (job->status) {
248 case JOB_STATUS_UNDEFINED:
249 case JOB_STATUS_CREATED:
250 case JOB_STATUS_RUNNING:
251 case JOB_STATUS_PAUSED:
252 case JOB_STATUS_READY:
253 case JOB_STATUS_STANDBY:
254 return false;
255 case JOB_STATUS_WAITING:
256 case JOB_STATUS_PENDING:
257 case JOB_STATUS_ABORTING:
258 case JOB_STATUS_CONCLUDED:
259 case JOB_STATUS_NULL:
260 return true;
261 default:
262 g_assert_not_reached();
263 }
264 return false;
265 }
266
267 static bool job_started(Job *job)
268 {
269 return job->co;
270 }
271
272 static bool job_should_pause(Job *job)
273 {
274 return job->pause_count > 0;
275 }
276
277 Job *job_next(Job *job)
278 {
279 if (!job) {
280 return QLIST_FIRST(&jobs);
281 }
282 return QLIST_NEXT(job, job_list);
283 }
284
285 Job *job_get(const char *id)
286 {
287 Job *job;
288
289 QLIST_FOREACH(job, &jobs, job_list) {
290 if (job->id && !strcmp(id, job->id)) {
291 return job;
292 }
293 }
294
295 return NULL;
296 }
297
298 static void job_sleep_timer_cb(void *opaque)
299 {
300 Job *job = opaque;
301
302 job_enter(job);
303 }
304
305 void *job_create(const char *job_id, const JobDriver *driver, JobTxn *txn,
306 AioContext *ctx, int flags, BlockCompletionFunc *cb,
307 void *opaque, Error **errp)
308 {
309 Job *job;
310
311 if (job_id) {
312 if (flags & JOB_INTERNAL) {
313 error_setg(errp, "Cannot specify job ID for internal job");
314 return NULL;
315 }
316 if (!id_wellformed(job_id)) {
317 error_setg(errp, "Invalid job ID '%s'", job_id);
318 return NULL;
319 }
320 if (job_get(job_id)) {
321 error_setg(errp, "Job ID '%s' already in use", job_id);
322 return NULL;
323 }
324 } else if (!(flags & JOB_INTERNAL)) {
325 error_setg(errp, "An explicit job ID is required");
326 return NULL;
327 }
328
329 job = g_malloc0(driver->instance_size);
330 job->driver = driver;
331 job->id = g_strdup(job_id);
332 job->refcnt = 1;
333 job->aio_context = ctx;
334 job->busy = false;
335 job->paused = true;
336 job->pause_count = 1;
337 job->auto_finalize = !(flags & JOB_MANUAL_FINALIZE);
338 job->auto_dismiss = !(flags & JOB_MANUAL_DISMISS);
339 job->cb = cb;
340 job->opaque = opaque;
341
342 notifier_list_init(&job->on_finalize_cancelled);
343 notifier_list_init(&job->on_finalize_completed);
344 notifier_list_init(&job->on_pending);
345 notifier_list_init(&job->on_ready);
346
347 job_state_transition(job, JOB_STATUS_CREATED);
348 aio_timer_init(qemu_get_aio_context(), &job->sleep_timer,
349 QEMU_CLOCK_REALTIME, SCALE_NS,
350 job_sleep_timer_cb, job);
351
352 QLIST_INSERT_HEAD(&jobs, job, job_list);
353
354 /* Single jobs are modeled as single-job transactions for sake of
355 * consolidating the job management logic */
356 if (!txn) {
357 txn = job_txn_new();
358 job_txn_add_job(txn, job);
359 job_txn_unref(txn);
360 } else {
361 job_txn_add_job(txn, job);
362 }
363
364 return job;
365 }
366
367 void job_ref(Job *job)
368 {
369 ++job->refcnt;
370 }
371
372 void job_unref(Job *job)
373 {
374 if (--job->refcnt == 0) {
375 assert(job->status == JOB_STATUS_NULL);
376 assert(!timer_pending(&job->sleep_timer));
377 assert(!job->txn);
378
379 if (job->driver->free) {
380 job->driver->free(job);
381 }
382
383 QLIST_REMOVE(job, job_list);
384
385 error_free(job->err);
386 g_free(job->id);
387 g_free(job);
388 }
389 }
390
391 void job_progress_update(Job *job, uint64_t done)
392 {
393 progress_work_done(&job->progress, done);
394 }
395
396 void job_progress_set_remaining(Job *job, uint64_t remaining)
397 {
398 progress_set_remaining(&job->progress, remaining);
399 }
400
401 void job_progress_increase_remaining(Job *job, uint64_t delta)
402 {
403 progress_increase_remaining(&job->progress, delta);
404 }
405
406 void job_event_cancelled(Job *job)
407 {
408 notifier_list_notify(&job->on_finalize_cancelled, job);
409 }
410
411 void job_event_completed(Job *job)
412 {
413 notifier_list_notify(&job->on_finalize_completed, job);
414 }
415
416 static void job_event_pending(Job *job)
417 {
418 notifier_list_notify(&job->on_pending, job);
419 }
420
421 static void job_event_ready(Job *job)
422 {
423 notifier_list_notify(&job->on_ready, job);
424 }
425
426 static void job_event_idle(Job *job)
427 {
428 notifier_list_notify(&job->on_idle, job);
429 }
430
431 void job_enter_cond(Job *job, bool(*fn)(Job *job))
432 {
433 if (!job_started(job)) {
434 return;
435 }
436 if (job->deferred_to_main_loop) {
437 return;
438 }
439
440 job_lock();
441 if (job->busy) {
442 job_unlock();
443 return;
444 }
445
446 if (fn && !fn(job)) {
447 job_unlock();
448 return;
449 }
450
451 assert(!job->deferred_to_main_loop);
452 timer_del(&job->sleep_timer);
453 job->busy = true;
454 job_unlock();
455 aio_co_enter(job->aio_context, job->co);
456 }
457
458 void job_enter(Job *job)
459 {
460 job_enter_cond(job, NULL);
461 }
462
463 /* Yield, and schedule a timer to reenter the coroutine after @ns nanoseconds.
464 * Reentering the job coroutine with job_enter() before the timer has expired
465 * is allowed and cancels the timer.
466 *
467 * If @ns is (uint64_t) -1, no timer is scheduled and job_enter() must be
468 * called explicitly. */
469 static void coroutine_fn job_do_yield(Job *job, uint64_t ns)
470 {
471 job_lock();
472 if (ns != -1) {
473 timer_mod(&job->sleep_timer, ns);
474 }
475 job->busy = false;
476 job_event_idle(job);
477 job_unlock();
478 qemu_coroutine_yield();
479
480 /* Set by job_enter_cond() before re-entering the coroutine. */
481 assert(job->busy);
482 }
483
484 void coroutine_fn job_pause_point(Job *job)
485 {
486 assert(job && job_started(job));
487
488 if (!job_should_pause(job)) {
489 return;
490 }
491 if (job_is_cancelled(job)) {
492 return;
493 }
494
495 if (job->driver->pause) {
496 job->driver->pause(job);
497 }
498
499 if (job_should_pause(job) && !job_is_cancelled(job)) {
500 JobStatus status = job->status;
501 job_state_transition(job, status == JOB_STATUS_READY
502 ? JOB_STATUS_STANDBY
503 : JOB_STATUS_PAUSED);
504 job->paused = true;
505 job_do_yield(job, -1);
506 job->paused = false;
507 job_state_transition(job, status);
508 }
509
510 if (job->driver->resume) {
511 job->driver->resume(job);
512 }
513 }
514
515 void job_yield(Job *job)
516 {
517 assert(job->busy);
518
519 /* Check cancellation *before* setting busy = false, too! */
520 if (job_is_cancelled(job)) {
521 return;
522 }
523
524 if (!job_should_pause(job)) {
525 job_do_yield(job, -1);
526 }
527
528 job_pause_point(job);
529 }
530
531 void coroutine_fn job_sleep_ns(Job *job, int64_t ns)
532 {
533 assert(job->busy);
534
535 /* Check cancellation *before* setting busy = false, too! */
536 if (job_is_cancelled(job)) {
537 return;
538 }
539
540 if (!job_should_pause(job)) {
541 job_do_yield(job, qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + ns);
542 }
543
544 job_pause_point(job);
545 }
546
547 /* Assumes the block_job_mutex is held */
548 static bool job_timer_not_pending(Job *job)
549 {
550 return !timer_pending(&job->sleep_timer);
551 }
552
553 void job_pause(Job *job)
554 {
555 job->pause_count++;
556 }
557
558 void job_resume(Job *job)
559 {
560 assert(job->pause_count > 0);
561 job->pause_count--;
562 if (job->pause_count) {
563 return;
564 }
565
566 /* kick only if no timer is pending */
567 job_enter_cond(job, job_timer_not_pending);
568 }
569
570 void job_user_pause(Job *job, Error **errp)
571 {
572 if (job_apply_verb(job, JOB_VERB_PAUSE, errp)) {
573 return;
574 }
575 if (job->user_paused) {
576 error_setg(errp, "Job is already paused");
577 return;
578 }
579 job->user_paused = true;
580 job_pause(job);
581 }
582
583 bool job_user_paused(Job *job)
584 {
585 return job->user_paused;
586 }
587
588 void job_user_resume(Job *job, Error **errp)
589 {
590 assert(job);
591 if (!job->user_paused || job->pause_count <= 0) {
592 error_setg(errp, "Can't resume a job that was not paused");
593 return;
594 }
595 if (job_apply_verb(job, JOB_VERB_RESUME, errp)) {
596 return;
597 }
598 if (job->driver->user_resume) {
599 job->driver->user_resume(job);
600 }
601 job->user_paused = false;
602 job_resume(job);
603 }
604
605 static void job_do_dismiss(Job *job)
606 {
607 assert(job);
608 job->busy = false;
609 job->paused = false;
610 job->deferred_to_main_loop = true;
611
612 job_txn_del_job(job);
613
614 job_state_transition(job, JOB_STATUS_NULL);
615 job_unref(job);
616 }
617
618 void job_dismiss(Job **jobptr, Error **errp)
619 {
620 Job *job = *jobptr;
621 /* similarly to _complete, this is QMP-interface only. */
622 assert(job->id);
623 if (job_apply_verb(job, JOB_VERB_DISMISS, errp)) {
624 return;
625 }
626
627 job_do_dismiss(job);
628 *jobptr = NULL;
629 }
630
631 void job_early_fail(Job *job)
632 {
633 assert(job->status == JOB_STATUS_CREATED);
634 job_do_dismiss(job);
635 }
636
637 static void job_conclude(Job *job)
638 {
639 job_state_transition(job, JOB_STATUS_CONCLUDED);
640 if (job->auto_dismiss || !job_started(job)) {
641 job_do_dismiss(job);
642 }
643 }
644
645 static void job_update_rc(Job *job)
646 {
647 if (!job->ret && job_is_cancelled(job)) {
648 job->ret = -ECANCELED;
649 }
650 if (job->ret) {
651 if (!job->err) {
652 error_setg(&job->err, "%s", strerror(-job->ret));
653 }
654 job_state_transition(job, JOB_STATUS_ABORTING);
655 }
656 }
657
658 static void job_commit(Job *job)
659 {
660 assert(!job->ret);
661 if (job->driver->commit) {
662 job->driver->commit(job);
663 }
664 }
665
666 static void job_abort(Job *job)
667 {
668 assert(job->ret);
669 if (job->driver->abort) {
670 job->driver->abort(job);
671 }
672 }
673
674 static void job_clean(Job *job)
675 {
676 if (job->driver->clean) {
677 job->driver->clean(job);
678 }
679 }
680
681 static int job_finalize_single(Job *job)
682 {
683 assert(job_is_completed(job));
684
685 /* Ensure abort is called for late-transactional failures */
686 job_update_rc(job);
687
688 if (!job->ret) {
689 job_commit(job);
690 } else {
691 job_abort(job);
692 }
693 job_clean(job);
694
695 if (job->cb) {
696 job->cb(job->opaque, job->ret);
697 }
698
699 /* Emit events only if we actually started */
700 if (job_started(job)) {
701 if (job_is_cancelled(job)) {
702 job_event_cancelled(job);
703 } else {
704 job_event_completed(job);
705 }
706 }
707
708 job_txn_del_job(job);
709 job_conclude(job);
710 return 0;
711 }
712
713 static void job_cancel_async(Job *job, bool force)
714 {
715 if (job->user_paused) {
716 /* Do not call job_enter here, the caller will handle it. */
717 if (job->driver->user_resume) {
718 job->driver->user_resume(job);
719 }
720 job->user_paused = false;
721 assert(job->pause_count > 0);
722 job->pause_count--;
723 }
724 job->cancelled = true;
725 /* To prevent 'force == false' overriding a previous 'force == true' */
726 job->force_cancel |= force;
727 }
728
729 static void job_completed_txn_abort(Job *job)
730 {
731 AioContext *outer_ctx = job->aio_context;
732 AioContext *ctx;
733 JobTxn *txn = job->txn;
734 Job *other_job;
735
736 if (txn->aborting) {
737 /*
738 * We are cancelled by another job, which will handle everything.
739 */
740 return;
741 }
742 txn->aborting = true;
743 job_txn_ref(txn);
744
745 /* We can only hold the single job's AioContext lock while calling
746 * job_finalize_single() because the finalization callbacks can involve
747 * calls of AIO_WAIT_WHILE(), which could deadlock otherwise. */
748 aio_context_release(outer_ctx);
749
750 /* Other jobs are effectively cancelled by us, set the status for
751 * them; this job, however, may or may not be cancelled, depending
752 * on the caller, so leave it. */
753 QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
754 if (other_job != job) {
755 ctx = other_job->aio_context;
756 aio_context_acquire(ctx);
757 job_cancel_async(other_job, false);
758 aio_context_release(ctx);
759 }
760 }
761 while (!QLIST_EMPTY(&txn->jobs)) {
762 other_job = QLIST_FIRST(&txn->jobs);
763 ctx = other_job->aio_context;
764 aio_context_acquire(ctx);
765 if (!job_is_completed(other_job)) {
766 assert(job_is_cancelled(other_job));
767 job_finish_sync(other_job, NULL, NULL);
768 }
769 job_finalize_single(other_job);
770 aio_context_release(ctx);
771 }
772
773 aio_context_acquire(outer_ctx);
774
775 job_txn_unref(txn);
776 }
777
778 static int job_prepare(Job *job)
779 {
780 if (job->ret == 0 && job->driver->prepare) {
781 job->ret = job->driver->prepare(job);
782 job_update_rc(job);
783 }
784 return job->ret;
785 }
786
787 static int job_needs_finalize(Job *job)
788 {
789 return !job->auto_finalize;
790 }
791
792 static void job_do_finalize(Job *job)
793 {
794 int rc;
795 assert(job && job->txn);
796
797 /* prepare the transaction to complete */
798 rc = job_txn_apply(job, job_prepare);
799 if (rc) {
800 job_completed_txn_abort(job);
801 } else {
802 job_txn_apply(job, job_finalize_single);
803 }
804 }
805
806 void job_finalize(Job *job, Error **errp)
807 {
808 assert(job && job->id);
809 if (job_apply_verb(job, JOB_VERB_FINALIZE, errp)) {
810 return;
811 }
812 job_do_finalize(job);
813 }
814
815 static int job_transition_to_pending(Job *job)
816 {
817 job_state_transition(job, JOB_STATUS_PENDING);
818 if (!job->auto_finalize) {
819 job_event_pending(job);
820 }
821 return 0;
822 }
823
824 void job_transition_to_ready(Job *job)
825 {
826 job_state_transition(job, JOB_STATUS_READY);
827 job_event_ready(job);
828 }
829
830 static void job_completed_txn_success(Job *job)
831 {
832 JobTxn *txn = job->txn;
833 Job *other_job;
834
835 job_state_transition(job, JOB_STATUS_WAITING);
836
837 /*
838 * Successful completion, see if there are other running jobs in this
839 * txn.
840 */
841 QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
842 if (!job_is_completed(other_job)) {
843 return;
844 }
845 assert(other_job->ret == 0);
846 }
847
848 job_txn_apply(job, job_transition_to_pending);
849
850 /* If no jobs need manual finalization, automatically do so */
851 if (job_txn_apply(job, job_needs_finalize) == 0) {
852 job_do_finalize(job);
853 }
854 }
855
856 static void job_completed(Job *job)
857 {
858 assert(job && job->txn && !job_is_completed(job));
859
860 job_update_rc(job);
861 trace_job_completed(job, job->ret);
862 if (job->ret) {
863 job_completed_txn_abort(job);
864 } else {
865 job_completed_txn_success(job);
866 }
867 }
868
869 /** Useful only as a type shim for aio_bh_schedule_oneshot. */
870 static void job_exit(void *opaque)
871 {
872 Job *job = (Job *)opaque;
873 AioContext *ctx;
874
875 job_ref(job);
876 aio_context_acquire(job->aio_context);
877
878 /* This is a lie, we're not quiescent, but still doing the completion
879 * callbacks. However, completion callbacks tend to involve operations that
880 * drain block nodes, and if .drained_poll still returned true, we would
881 * deadlock. */
882 job->busy = false;
883 job_event_idle(job);
884
885 job_completed(job);
886
887 /*
888 * Note that calling job_completed can move the job to a different
889 * aio_context, so we cannot cache from above. job_txn_apply takes care of
890 * acquiring the new lock, and we ref/unref to avoid job_completed freeing
891 * the job underneath us.
892 */
893 ctx = job->aio_context;
894 job_unref(job);
895 aio_context_release(ctx);
896 }
897
898 /**
899 * All jobs must allow a pause point before entering their job proper. This
900 * ensures that jobs can be paused prior to being started, then resumed later.
901 */
902 static void coroutine_fn job_co_entry(void *opaque)
903 {
904 Job *job = opaque;
905
906 assert(job && job->driver && job->driver->run);
907 job_pause_point(job);
908 job->ret = job->driver->run(job, &job->err);
909 job->deferred_to_main_loop = true;
910 job->busy = true;
911 aio_bh_schedule_oneshot(qemu_get_aio_context(), job_exit, job);
912 }
913
914 void job_start(Job *job)
915 {
916 assert(job && !job_started(job) && job->paused &&
917 job->driver && job->driver->run);
918 job->co = qemu_coroutine_create(job_co_entry, job);
919 job->pause_count--;
920 job->busy = true;
921 job->paused = false;
922 job_state_transition(job, JOB_STATUS_RUNNING);
923 aio_co_enter(job->aio_context, job->co);
924 }
925
926 void job_cancel(Job *job, bool force)
927 {
928 if (job->status == JOB_STATUS_CONCLUDED) {
929 job_do_dismiss(job);
930 return;
931 }
932 job_cancel_async(job, force);
933 if (!job_started(job)) {
934 job_completed(job);
935 } else if (job->deferred_to_main_loop) {
936 job_completed_txn_abort(job);
937 } else {
938 job_enter(job);
939 }
940 }
941
942 void job_user_cancel(Job *job, bool force, Error **errp)
943 {
944 if (job_apply_verb(job, JOB_VERB_CANCEL, errp)) {
945 return;
946 }
947 job_cancel(job, force);
948 }
949
950 /* A wrapper around job_cancel() taking an Error ** parameter so it may be
951 * used with job_finish_sync() without the need for (rather nasty) function
952 * pointer casts there. */
953 static void job_cancel_err(Job *job, Error **errp)
954 {
955 job_cancel(job, false);
956 }
957
958 int job_cancel_sync(Job *job)
959 {
960 return job_finish_sync(job, &job_cancel_err, NULL);
961 }
962
963 void job_cancel_sync_all(void)
964 {
965 Job *job;
966 AioContext *aio_context;
967
968 while ((job = job_next(NULL))) {
969 aio_context = job->aio_context;
970 aio_context_acquire(aio_context);
971 job_cancel_sync(job);
972 aio_context_release(aio_context);
973 }
974 }
975
976 int job_complete_sync(Job *job, Error **errp)
977 {
978 return job_finish_sync(job, job_complete, errp);
979 }
980
981 void job_complete(Job *job, Error **errp)
982 {
983 /* Should not be reachable via external interface for internal jobs */
984 assert(job->id);
985 if (job_apply_verb(job, JOB_VERB_COMPLETE, errp)) {
986 return;
987 }
988 if (job->pause_count || job_is_cancelled(job) || !job->driver->complete) {
989 error_setg(errp, "The active block job '%s' cannot be completed",
990 job->id);
991 return;
992 }
993
994 job->driver->complete(job, errp);
995 }
996
997 int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp)
998 {
999 Error *local_err = NULL;
1000 int ret;
1001
1002 job_ref(job);
1003
1004 if (finish) {
1005 finish(job, &local_err);
1006 }
1007 if (local_err) {
1008 error_propagate(errp, local_err);
1009 job_unref(job);
1010 return -EBUSY;
1011 }
1012
1013 AIO_WAIT_WHILE(job->aio_context,
1014 (job_enter(job), !job_is_completed(job)));
1015
1016 ret = (job_is_cancelled(job) && job->ret == 0) ? -ECANCELED : job->ret;
1017 job_unref(job);
1018 return ret;
1019 }