xref: /openbmc/qemu/job.c (revision 2c44220d055d12142f27cf513848f17d6007ae35)
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  }
1020