qemu

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
/*
36
 * The job API is composed of two categories of functions.
37
 *
38
 * The first includes functions used by the monitor.  The monitor is
39
 * peculiar in that it accesses the job list with job_get, and
40
 * therefore needs consistency across job_get and the actual operation
41
 * (e.g. job_user_cancel). To achieve this consistency, the caller
42
 * calls job_lock/job_unlock itself around the whole operation.
43
 *
44
 *
45
 * The second includes functions used by the job drivers and sometimes
46
 * by the core block layer. These delegate the locking to the callee instead.
47
 */
48

49
/*
50
 * job_mutex protects the jobs list, but also makes the
51
 * struct job fields thread-safe.
52
 */
53
QemuMutex job_mutex;
54

55
/* Protected by job_mutex */
56
static QLIST_HEAD(, Job) jobs = QLIST_HEAD_INITIALIZER(jobs);
57

58
/* Job State Transition Table */
59
bool JobSTT[JOB_STATUS__MAX][JOB_STATUS__MAX] = {
60
                                    /* U, C, R, P, Y, S, W, D, X, E, N */
61
    /* U: */ [JOB_STATUS_UNDEFINED] = {0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0},
62
    /* C: */ [JOB_STATUS_CREATED]   = {0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1},
63
    /* R: */ [JOB_STATUS_RUNNING]   = {0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0},
64
    /* P: */ [JOB_STATUS_PAUSED]    = {0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0},
65
    /* Y: */ [JOB_STATUS_READY]     = {0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0},
66
    /* S: */ [JOB_STATUS_STANDBY]   = {0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0},
67
    /* W: */ [JOB_STATUS_WAITING]   = {0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0},
68
    /* D: */ [JOB_STATUS_PENDING]   = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0},
69
    /* X: */ [JOB_STATUS_ABORTING]  = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0},
70
    /* E: */ [JOB_STATUS_CONCLUDED] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
71
    /* N: */ [JOB_STATUS_NULL]      = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
72
};
73

74
bool JobVerbTable[JOB_VERB__MAX][JOB_STATUS__MAX] = {
75
                                    /* U, C, R, P, Y, S, W, D, X, E, N */
76
    [JOB_VERB_CANCEL]               = {0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0},
77
    [JOB_VERB_PAUSE]                = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
78
    [JOB_VERB_RESUME]               = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
79
    [JOB_VERB_SET_SPEED]            = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
80
    [JOB_VERB_COMPLETE]             = {0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0},
81
    [JOB_VERB_FINALIZE]             = {0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0},
82
    [JOB_VERB_DISMISS]              = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0},
83
    [JOB_VERB_CHANGE]               = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
84
};
85

86
/* Transactional group of jobs */
87
struct JobTxn {
88

89
    /* Is this txn being cancelled? */
90
    bool aborting;
91

92
    /* List of jobs */
93
    QLIST_HEAD(, Job) jobs;
94

95
    /* Reference count */
96
    int refcnt;
97
};
98

99
void job_lock(void)
100
{
101
    qemu_mutex_lock(&job_mutex);
102
}
103

104
void job_unlock(void)
105
{
106
    qemu_mutex_unlock(&job_mutex);
107
}
108

109
static void __attribute__((__constructor__)) job_init(void)
110
{
111
    qemu_mutex_init(&job_mutex);
112
}
113

114
JobTxn *job_txn_new(void)
115
{
116
    JobTxn *txn = g_new0(JobTxn, 1);
117
    QLIST_INIT(&txn->jobs);
118
    txn->refcnt = 1;
119
    return txn;
120
}
121

122
/* Called with job_mutex held. */
123
static void job_txn_ref_locked(JobTxn *txn)
124
{
125
    txn->refcnt++;
126
}
127

128
void job_txn_unref_locked(JobTxn *txn)
129
{
130
    if (txn && --txn->refcnt == 0) {
131
        g_free(txn);
132
    }
133
}
134

135
void job_txn_unref(JobTxn *txn)
136
{
137
    JOB_LOCK_GUARD();
138
    job_txn_unref_locked(txn);
139
}
140

141
/**
142
 * @txn: The transaction (may be NULL)
143
 * @job: Job to add to the transaction
144
 *
145
 * Add @job to the transaction.  The @job must not already be in a transaction.
146
 * The caller must call either job_txn_unref() or job_completed() to release
147
 * the reference that is automatically grabbed here.
148
 *
149
 * If @txn is NULL, the function does nothing.
150
 *
151
 * Called with job_mutex held.
152
 */
153
static void job_txn_add_job_locked(JobTxn *txn, Job *job)
154
{
155
    if (!txn) {
156
        return;
157
    }
158

159
    assert(!job->txn);
160
    job->txn = txn;
161

162
    QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
163
    job_txn_ref_locked(txn);
164
}
165

166
/* Called with job_mutex held. */
167
static void job_txn_del_job_locked(Job *job)
168
{
169
    if (job->txn) {
170
        QLIST_REMOVE(job, txn_list);
171
        job_txn_unref_locked(job->txn);
172
        job->txn = NULL;
173
    }
174
}
175

176
/* Called with job_mutex held, but releases it temporarily. */
177
static int job_txn_apply_locked(Job *job, int fn(Job *))
178
{
179
    Job *other_job, *next;
180
    JobTxn *txn = job->txn;
181
    int rc = 0;
182

183
    /*
184
     * Similar to job_completed_txn_abort, we take each job's lock before
185
     * applying fn, but since we assume that outer_ctx is held by the caller,
186
     * we need to release it here to avoid holding the lock twice - which would
187
     * break AIO_WAIT_WHILE from within fn.
188
     */
189
    job_ref_locked(job);
190

191
    QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
192
        rc = fn(other_job);
193
        if (rc) {
194
            break;
195
        }
196
    }
197

198
    job_unref_locked(job);
199
    return rc;
200
}
201

202
bool job_is_internal(Job *job)
203
{
204
    return (job->id == NULL);
205
}
206

207
/* Called with job_mutex held. */
208
static void job_state_transition_locked(Job *job, JobStatus s1)
209
{
210
    JobStatus s0 = job->status;
211
    assert(s1 >= 0 && s1 < JOB_STATUS__MAX);
212
    trace_job_state_transition(job, job->ret,
213
                               JobSTT[s0][s1] ? "allowed" : "disallowed",
214
                               JobStatus_str(s0), JobStatus_str(s1));
215
    assert(JobSTT[s0][s1]);
216
    job->status = s1;
217

218
    if (!job_is_internal(job) && s1 != s0) {
219
        qapi_event_send_job_status_change(job->id, job->status);
220
    }
221
}
222

223
int job_apply_verb_locked(Job *job, JobVerb verb, Error **errp)
224
{
225
    JobStatus s0 = job->status;
226
    assert(verb >= 0 && verb < JOB_VERB__MAX);
227
    trace_job_apply_verb(job, JobStatus_str(s0), JobVerb_str(verb),
228
                         JobVerbTable[verb][s0] ? "allowed" : "prohibited");
229
    if (JobVerbTable[verb][s0]) {
230
        return 0;
231
    }
232
    error_setg(errp, "Job '%s' in state '%s' cannot accept command verb '%s'",
233
               job->id, JobStatus_str(s0), JobVerb_str(verb));
234
    return -EPERM;
235
}
236

237
JobType job_type(const Job *job)
238
{
239
    return job->driver->job_type;
240
}
241

242
const char *job_type_str(const Job *job)
243
{
244
    return JobType_str(job_type(job));
245
}
246

247
bool job_is_cancelled_locked(Job *job)
248
{
249
    /* force_cancel may be true only if cancelled is true, too */
250
    assert(job->cancelled || !job->force_cancel);
251
    return job->force_cancel;
252
}
253

254
bool job_is_cancelled(Job *job)
255
{
256
    JOB_LOCK_GUARD();
257
    return job_is_cancelled_locked(job);
258
}
259

260
/* Called with job_mutex held. */
261
static bool job_cancel_requested_locked(Job *job)
262
{
263
    return job->cancelled;
264
}
265

266
bool job_cancel_requested(Job *job)
267
{
268
    JOB_LOCK_GUARD();
269
    return job_cancel_requested_locked(job);
270
}
271

272
bool job_is_ready_locked(Job *job)
273
{
274
    switch (job->status) {
275
    case JOB_STATUS_UNDEFINED:
276
    case JOB_STATUS_CREATED:
277
    case JOB_STATUS_RUNNING:
278
    case JOB_STATUS_PAUSED:
279
    case JOB_STATUS_WAITING:
280
    case JOB_STATUS_PENDING:
281
    case JOB_STATUS_ABORTING:
282
    case JOB_STATUS_CONCLUDED:
283
    case JOB_STATUS_NULL:
284
        return false;
285
    case JOB_STATUS_READY:
286
    case JOB_STATUS_STANDBY:
287
        return true;
288
    default:
289
        g_assert_not_reached();
290
    }
291
    return false;
292
}
293

294
bool job_is_ready(Job *job)
295
{
296
    JOB_LOCK_GUARD();
297
    return job_is_ready_locked(job);
298
}
299

300
bool job_is_completed_locked(Job *job)
301
{
302
    switch (job->status) {
303
    case JOB_STATUS_UNDEFINED:
304
    case JOB_STATUS_CREATED:
305
    case JOB_STATUS_RUNNING:
306
    case JOB_STATUS_PAUSED:
307
    case JOB_STATUS_READY:
308
    case JOB_STATUS_STANDBY:
309
        return false;
310
    case JOB_STATUS_WAITING:
311
    case JOB_STATUS_PENDING:
312
    case JOB_STATUS_ABORTING:
313
    case JOB_STATUS_CONCLUDED:
314
    case JOB_STATUS_NULL:
315
        return true;
316
    default:
317
        g_assert_not_reached();
318
    }
319
    return false;
320
}
321

322
static bool job_is_completed(Job *job)
323
{
324
    JOB_LOCK_GUARD();
325
    return job_is_completed_locked(job);
326
}
327

328
static bool job_started_locked(Job *job)
329
{
330
    return job->co;
331
}
332

333
/* Called with job_mutex held. */
334
static bool job_should_pause_locked(Job *job)
335
{
336
    return job->pause_count > 0;
337
}
338

339
Job *job_next_locked(Job *job)
340
{
341
    if (!job) {
342
        return QLIST_FIRST(&jobs);
343
    }
344
    return QLIST_NEXT(job, job_list);
345
}
346

347
Job *job_next(Job *job)
348
{
349
    JOB_LOCK_GUARD();
350
    return job_next_locked(job);
351
}
352

353
Job *job_get_locked(const char *id)
354
{
355
    Job *job;
356

357
    QLIST_FOREACH(job, &jobs, job_list) {
358
        if (job->id && !strcmp(id, job->id)) {
359
            return job;
360
        }
361
    }
362

363
    return NULL;
364
}
365

366
void job_set_aio_context(Job *job, AioContext *ctx)
367
{
368
    /* protect against read in job_finish_sync_locked and job_start */
369
    GLOBAL_STATE_CODE();
370
    /* protect against read in job_do_yield_locked */
371
    JOB_LOCK_GUARD();
372
    /* ensure the job is quiescent while the AioContext is changed */
373
    assert(job->paused || job_is_completed_locked(job));
374
    job->aio_context = ctx;
375
}
376

377
/* Called with job_mutex *not* held. */
378
static void job_sleep_timer_cb(void *opaque)
379
{
380
    Job *job = opaque;
381

382
    job_enter(job);
383
}
384

385
void *job_create(const char *job_id, const JobDriver *driver, JobTxn *txn,
386
                 AioContext *ctx, int flags, BlockCompletionFunc *cb,
387
                 void *opaque, Error **errp)
388
{
389
    Job *job;
390

391
    JOB_LOCK_GUARD();
392

393
    if (job_id) {
394
        if (flags & JOB_INTERNAL) {
395
            error_setg(errp, "Cannot specify job ID for internal job");
396
            return NULL;
397
        }
398
        if (!id_wellformed(job_id)) {
399
            error_setg(errp, "Invalid job ID '%s'", job_id);
400
            return NULL;
401
        }
402
        if (job_get_locked(job_id)) {
403
            error_setg(errp, "Job ID '%s' already in use", job_id);
404
            return NULL;
405
        }
406
    } else if (!(flags & JOB_INTERNAL)) {
407
        error_setg(errp, "An explicit job ID is required");
408
        return NULL;
409
    }
410

411
    job = g_malloc0(driver->instance_size);
412
    job->driver        = driver;
413
    job->id            = g_strdup(job_id);
414
    job->refcnt        = 1;
415
    job->aio_context   = ctx;
416
    job->busy          = false;
417
    job->paused        = true;
418
    job->pause_count   = 1;
419
    job->auto_finalize = !(flags & JOB_MANUAL_FINALIZE);
420
    job->auto_dismiss  = !(flags & JOB_MANUAL_DISMISS);
421
    job->cb            = cb;
422
    job->opaque        = opaque;
423

424
    progress_init(&job->progress);
425

426
    notifier_list_init(&job->on_finalize_cancelled);
427
    notifier_list_init(&job->on_finalize_completed);
428
    notifier_list_init(&job->on_pending);
429
    notifier_list_init(&job->on_ready);
430
    notifier_list_init(&job->on_idle);
431

432
    job_state_transition_locked(job, JOB_STATUS_CREATED);
433
    aio_timer_init(qemu_get_aio_context(), &job->sleep_timer,
434
                   QEMU_CLOCK_REALTIME, SCALE_NS,
435
                   job_sleep_timer_cb, job);
436

437
    QLIST_INSERT_HEAD(&jobs, job, job_list);
438

439
    /* Single jobs are modeled as single-job transactions for sake of
440
     * consolidating the job management logic */
441
    if (!txn) {
442
        txn = job_txn_new();
443
        job_txn_add_job_locked(txn, job);
444
        job_txn_unref_locked(txn);
445
    } else {
446
        job_txn_add_job_locked(txn, job);
447
    }
448

449
    return job;
450
}
451

452
void job_ref_locked(Job *job)
453
{
454
    ++job->refcnt;
455
}
456

457
void job_unref_locked(Job *job)
458
{
459
    GLOBAL_STATE_CODE();
460

461
    if (--job->refcnt == 0) {
462
        assert(job->status == JOB_STATUS_NULL);
463
        assert(!timer_pending(&job->sleep_timer));
464
        assert(!job->txn);
465

466
        if (job->driver->free) {
467
            job_unlock();
468
            job->driver->free(job);
469
            job_lock();
470
        }
471

472
        QLIST_REMOVE(job, job_list);
473

474
        progress_destroy(&job->progress);
475
        error_free(job->err);
476
        g_free(job->id);
477
        g_free(job);
478
    }
479
}
480

481
void job_progress_update(Job *job, uint64_t done)
482
{
483
    progress_work_done(&job->progress, done);
484
}
485

486
void job_progress_set_remaining(Job *job, uint64_t remaining)
487
{
488
    progress_set_remaining(&job->progress, remaining);
489
}
490

491
void job_progress_increase_remaining(Job *job, uint64_t delta)
492
{
493
    progress_increase_remaining(&job->progress, delta);
494
}
495

496
/**
497
 * To be called when a cancelled job is finalised.
498
 * Called with job_mutex held.
499
 */
500
static void job_event_cancelled_locked(Job *job)
501
{
502
    notifier_list_notify(&job->on_finalize_cancelled, job);
503
}
504

505
/**
506
 * To be called when a successfully completed job is finalised.
507
 * Called with job_mutex held.
508
 */
509
static void job_event_completed_locked(Job *job)
510
{
511
    notifier_list_notify(&job->on_finalize_completed, job);
512
}
513

514
/* Called with job_mutex held. */
515
static void job_event_pending_locked(Job *job)
516
{
517
    notifier_list_notify(&job->on_pending, job);
518
}
519

520
/* Called with job_mutex held. */
521
static void job_event_ready_locked(Job *job)
522
{
523
    notifier_list_notify(&job->on_ready, job);
524
}
525

526
/* Called with job_mutex held. */
527
static void job_event_idle_locked(Job *job)
528
{
529
    notifier_list_notify(&job->on_idle, job);
530
}
531

532
void job_enter_cond_locked(Job *job, bool(*fn)(Job *job))
533
{
534
    if (!job_started_locked(job)) {
535
        return;
536
    }
537
    if (job->deferred_to_main_loop) {
538
        return;
539
    }
540

541
    if (job->busy) {
542
        return;
543
    }
544

545
    if (fn && !fn(job)) {
546
        return;
547
    }
548

549
    assert(!job->deferred_to_main_loop);
550
    timer_del(&job->sleep_timer);
551
    job->busy = true;
552
    job_unlock();
553
    aio_co_wake(job->co);
554
    job_lock();
555
}
556

557
void job_enter(Job *job)
558
{
559
    JOB_LOCK_GUARD();
560
    job_enter_cond_locked(job, NULL);
561
}
562

563
/* Yield, and schedule a timer to reenter the coroutine after @ns nanoseconds.
564
 * Reentering the job coroutine with job_enter() before the timer has expired
565
 * is allowed and cancels the timer.
566
 *
567
 * If @ns is (uint64_t) -1, no timer is scheduled and job_enter() must be
568
 * called explicitly.
569
 *
570
 * Called with job_mutex held, but releases it temporarily.
571
 */
572
static void coroutine_fn job_do_yield_locked(Job *job, uint64_t ns)
573
{
574
    AioContext *next_aio_context;
575

576
    if (ns != -1) {
577
        timer_mod(&job->sleep_timer, ns);
578
    }
579
    job->busy = false;
580
    job_event_idle_locked(job);
581
    job_unlock();
582
    qemu_coroutine_yield();
583
    job_lock();
584

585
    next_aio_context = job->aio_context;
586
    /*
587
     * Coroutine has resumed, but in the meanwhile the job AioContext
588
     * might have changed via bdrv_try_change_aio_context(), so we need to move
589
     * the coroutine too in the new aiocontext.
590
     */
591
    while (qemu_get_current_aio_context() != next_aio_context) {
592
        job_unlock();
593
        aio_co_reschedule_self(next_aio_context);
594
        job_lock();
595
        next_aio_context = job->aio_context;
596
    }
597

598
    /* Set by job_enter_cond_locked() before re-entering the coroutine.  */
599
    assert(job->busy);
600
}
601

602
/* Called with job_mutex held, but releases it temporarily. */
603
static void coroutine_fn job_pause_point_locked(Job *job)
604
{
605
    assert(job && job_started_locked(job));
606

607
    if (!job_should_pause_locked(job)) {
608
        return;
609
    }
610
    if (job_is_cancelled_locked(job)) {
611
        return;
612
    }
613

614
    if (job->driver->pause) {
615
        job_unlock();
616
        job->driver->pause(job);
617
        job_lock();
618
    }
619

620
    if (job_should_pause_locked(job) && !job_is_cancelled_locked(job)) {
621
        JobStatus status = job->status;
622
        job_state_transition_locked(job, status == JOB_STATUS_READY
623
                                    ? JOB_STATUS_STANDBY
624
                                    : JOB_STATUS_PAUSED);
625
        job->paused = true;
626
        job_do_yield_locked(job, -1);
627
        job->paused = false;
628
        job_state_transition_locked(job, status);
629
    }
630

631
    if (job->driver->resume) {
632
        job_unlock();
633
        job->driver->resume(job);
634
        job_lock();
635
    }
636
}
637

638
void coroutine_fn job_pause_point(Job *job)
639
{
640
    JOB_LOCK_GUARD();
641
    job_pause_point_locked(job);
642
}
643

644
void coroutine_fn job_yield(Job *job)
645
{
646
    JOB_LOCK_GUARD();
647
    assert(job->busy);
648

649
    /* Check cancellation *before* setting busy = false, too!  */
650
    if (job_is_cancelled_locked(job)) {
651
        return;
652
    }
653

654
    if (!job_should_pause_locked(job)) {
655
        job_do_yield_locked(job, -1);
656
    }
657

658
    job_pause_point_locked(job);
659
}
660

661
void coroutine_fn job_sleep_ns(Job *job, int64_t ns)
662
{
663
    JOB_LOCK_GUARD();
664
    assert(job->busy);
665

666
    /* Check cancellation *before* setting busy = false, too!  */
667
    if (job_is_cancelled_locked(job)) {
668
        return;
669
    }
670

671
    if (!job_should_pause_locked(job)) {
672
        job_do_yield_locked(job, qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + ns);
673
    }
674

675
    job_pause_point_locked(job);
676
}
677

678
/* Assumes the job_mutex is held */
679
static bool job_timer_not_pending_locked(Job *job)
680
{
681
    return !timer_pending(&job->sleep_timer);
682
}
683

684
void job_pause_locked(Job *job)
685
{
686
    job->pause_count++;
687
    if (!job->paused) {
688
        job_enter_cond_locked(job, NULL);
689
    }
690
}
691

692
void job_pause(Job *job)
693
{
694
    JOB_LOCK_GUARD();
695
    job_pause_locked(job);
696
}
697

698
void job_resume_locked(Job *job)
699
{
700
    assert(job->pause_count > 0);
701
    job->pause_count--;
702
    if (job->pause_count) {
703
        return;
704
    }
705

706
    /* kick only if no timer is pending */
707
    job_enter_cond_locked(job, job_timer_not_pending_locked);
708
}
709

710
void job_resume(Job *job)
711
{
712
    JOB_LOCK_GUARD();
713
    job_resume_locked(job);
714
}
715

716
void job_user_pause_locked(Job *job, Error **errp)
717
{
718
    if (job_apply_verb_locked(job, JOB_VERB_PAUSE, errp)) {
719
        return;
720
    }
721
    if (job->user_paused) {
722
        error_setg(errp, "Job is already paused");
723
        return;
724
    }
725
    job->user_paused = true;
726
    job_pause_locked(job);
727
}
728

729
bool job_user_paused_locked(Job *job)
730
{
731
    return job->user_paused;
732
}
733

734
void job_user_resume_locked(Job *job, Error **errp)
735
{
736
    assert(job);
737
    GLOBAL_STATE_CODE();
738
    if (!job->user_paused || job->pause_count <= 0) {
739
        error_setg(errp, "Can't resume a job that was not paused");
740
        return;
741
    }
742
    if (job_apply_verb_locked(job, JOB_VERB_RESUME, errp)) {
743
        return;
744
    }
745
    if (job->driver->user_resume) {
746
        job_unlock();
747
        job->driver->user_resume(job);
748
        job_lock();
749
    }
750
    job->user_paused = false;
751
    job_resume_locked(job);
752
}
753

754
/* Called with job_mutex held, but releases it temporarily. */
755
static void job_do_dismiss_locked(Job *job)
756
{
757
    assert(job);
758
    job->busy = false;
759
    job->paused = false;
760
    job->deferred_to_main_loop = true;
761

762
    job_txn_del_job_locked(job);
763

764
    job_state_transition_locked(job, JOB_STATUS_NULL);
765
    job_unref_locked(job);
766
}
767

768
void job_dismiss_locked(Job **jobptr, Error **errp)
769
{
770
    Job *job = *jobptr;
771
    /* similarly to _complete, this is QMP-interface only. */
772
    assert(job->id);
773
    if (job_apply_verb_locked(job, JOB_VERB_DISMISS, errp)) {
774
        return;
775
    }
776

777
    job_do_dismiss_locked(job);
778
    *jobptr = NULL;
779
}
780

781
void job_early_fail(Job *job)
782
{
783
    JOB_LOCK_GUARD();
784
    assert(job->status == JOB_STATUS_CREATED);
785
    job_do_dismiss_locked(job);
786
}
787

788
/* Called with job_mutex held. */
789
static void job_conclude_locked(Job *job)
790
{
791
    job_state_transition_locked(job, JOB_STATUS_CONCLUDED);
792
    if (job->auto_dismiss || !job_started_locked(job)) {
793
        job_do_dismiss_locked(job);
794
    }
795
}
796

797
/* Called with job_mutex held. */
798
static void job_update_rc_locked(Job *job)
799
{
800
    if (!job->ret && job_is_cancelled_locked(job)) {
801
        job->ret = -ECANCELED;
802
    }
803
    if (job->ret) {
804
        if (!job->err) {
805
            error_setg(&job->err, "%s", strerror(-job->ret));
806
        }
807
        job_state_transition_locked(job, JOB_STATUS_ABORTING);
808
    }
809
}
810

811
static void job_commit(Job *job)
812
{
813
    assert(!job->ret);
814
    GLOBAL_STATE_CODE();
815
    if (job->driver->commit) {
816
        job->driver->commit(job);
817
    }
818
}
819

820
static void job_abort(Job *job)
821
{
822
    assert(job->ret);
823
    GLOBAL_STATE_CODE();
824
    if (job->driver->abort) {
825
        job->driver->abort(job);
826
    }
827
}
828

829
static void job_clean(Job *job)
830
{
831
    GLOBAL_STATE_CODE();
832
    if (job->driver->clean) {
833
        job->driver->clean(job);
834
    }
835
}
836

837
/*
838
 * Called with job_mutex held, but releases it temporarily.
839
 */
840
static int job_finalize_single_locked(Job *job)
841
{
842
    int job_ret;
843

844
    assert(job_is_completed_locked(job));
845

846
    /* Ensure abort is called for late-transactional failures */
847
    job_update_rc_locked(job);
848

849
    job_ret = job->ret;
850
    job_unlock();
851

852
    if (!job_ret) {
853
        job_commit(job);
854
    } else {
855
        job_abort(job);
856
    }
857
    job_clean(job);
858

859
    if (job->cb) {
860
        job->cb(job->opaque, job_ret);
861
    }
862

863
    job_lock();
864

865
    /* Emit events only if we actually started */
866
    if (job_started_locked(job)) {
867
        if (job_is_cancelled_locked(job)) {
868
            job_event_cancelled_locked(job);
869
        } else {
870
            job_event_completed_locked(job);
871
        }
872
    }
873

874
    job_txn_del_job_locked(job);
875
    job_conclude_locked(job);
876
    return 0;
877
}
878

879
/*
880
 * Called with job_mutex held, but releases it temporarily.
881
 */
882
static void job_cancel_async_locked(Job *job, bool force)
883
{
884
    GLOBAL_STATE_CODE();
885
    if (job->driver->cancel) {
886
        job_unlock();
887
        force = job->driver->cancel(job, force);
888
        job_lock();
889
    } else {
890
        /* No .cancel() means the job will behave as if force-cancelled */
891
        force = true;
892
    }
893

894
    if (job->user_paused) {
895
        /* Do not call job_enter here, the caller will handle it.  */
896
        if (job->driver->user_resume) {
897
            job_unlock();
898
            job->driver->user_resume(job);
899
            job_lock();
900
        }
901
        job->user_paused = false;
902
        assert(job->pause_count > 0);
903
        job->pause_count--;
904
    }
905

906
    /*
907
     * Ignore soft cancel requests after the job is already done
908
     * (We will still invoke job->driver->cancel() above, but if the
909
     * job driver supports soft cancelling and the job is done, that
910
     * should be a no-op, too.  We still call it so it can override
911
     * @force.)
912
     */
913
    if (force || !job->deferred_to_main_loop) {
914
        job->cancelled = true;
915
        /* To prevent 'force == false' overriding a previous 'force == true' */
916
        job->force_cancel |= force;
917
    }
918
}
919

920
/*
921
 * Called with job_mutex held, but releases it temporarily.
922
 */
923
static void job_completed_txn_abort_locked(Job *job)
924
{
925
    JobTxn *txn = job->txn;
926
    Job *other_job;
927

928
    if (txn->aborting) {
929
        /*
930
         * We are cancelled by another job, which will handle everything.
931
         */
932
        return;
933
    }
934
    txn->aborting = true;
935
    job_txn_ref_locked(txn);
936

937
    job_ref_locked(job);
938

939
    /* Other jobs are effectively cancelled by us, set the status for
940
     * them; this job, however, may or may not be cancelled, depending
941
     * on the caller, so leave it. */
942
    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
943
        if (other_job != job) {
944
            /*
945
             * This is a transaction: If one job failed, no result will matter.
946
             * Therefore, pass force=true to terminate all other jobs as quickly
947
             * as possible.
948
             */
949
            job_cancel_async_locked(other_job, true);
950
        }
951
    }
952
    while (!QLIST_EMPTY(&txn->jobs)) {
953
        other_job = QLIST_FIRST(&txn->jobs);
954
        if (!job_is_completed_locked(other_job)) {
955
            assert(job_cancel_requested_locked(other_job));
956
            job_finish_sync_locked(other_job, NULL, NULL);
957
        }
958
        job_finalize_single_locked(other_job);
959
    }
960

961
    job_unref_locked(job);
962
    job_txn_unref_locked(txn);
963
}
964

965
/* Called with job_mutex held, but releases it temporarily */
966
static int job_prepare_locked(Job *job)
967
{
968
    int ret;
969

970
    GLOBAL_STATE_CODE();
971

972
    if (job->ret == 0 && job->driver->prepare) {
973
        job_unlock();
974
        ret = job->driver->prepare(job);
975
        job_lock();
976
        job->ret = ret;
977
        job_update_rc_locked(job);
978
    }
979

980
    return job->ret;
981
}
982

983
/* Called with job_mutex held */
984
static int job_needs_finalize_locked(Job *job)
985
{
986
    return !job->auto_finalize;
987
}
988

989
/* Called with job_mutex held */
990
static void job_do_finalize_locked(Job *job)
991
{
992
    int rc;
993
    assert(job && job->txn);
994

995
    /* prepare the transaction to complete */
996
    rc = job_txn_apply_locked(job, job_prepare_locked);
997
    if (rc) {
998
        job_completed_txn_abort_locked(job);
999
    } else {
1000
        job_txn_apply_locked(job, job_finalize_single_locked);
1001
    }
1002
}
1003

1004
void job_finalize_locked(Job *job, Error **errp)
1005
{
1006
    assert(job && job->id);
1007
    if (job_apply_verb_locked(job, JOB_VERB_FINALIZE, errp)) {
1008
        return;
1009
    }
1010
    job_do_finalize_locked(job);
1011
}
1012

1013
/* Called with job_mutex held. */
1014
static int job_transition_to_pending_locked(Job *job)
1015
{
1016
    job_state_transition_locked(job, JOB_STATUS_PENDING);
1017
    if (!job->auto_finalize) {
1018
        job_event_pending_locked(job);
1019
    }
1020
    return 0;
1021
}
1022

1023
void job_transition_to_ready(Job *job)
1024
{
1025
    JOB_LOCK_GUARD();
1026
    job_state_transition_locked(job, JOB_STATUS_READY);
1027
    job_event_ready_locked(job);
1028
}
1029

1030
/* Called with job_mutex held. */
1031
static void job_completed_txn_success_locked(Job *job)
1032
{
1033
    JobTxn *txn = job->txn;
1034
    Job *other_job;
1035

1036
    job_state_transition_locked(job, JOB_STATUS_WAITING);
1037

1038
    /*
1039
     * Successful completion, see if there are other running jobs in this
1040
     * txn.
1041
     */
1042
    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
1043
        if (!job_is_completed_locked(other_job)) {
1044
            return;
1045
        }
1046
        assert(other_job->ret == 0);
1047
    }
1048

1049
    job_txn_apply_locked(job, job_transition_to_pending_locked);
1050

1051
    /* If no jobs need manual finalization, automatically do so */
1052
    if (job_txn_apply_locked(job, job_needs_finalize_locked) == 0) {
1053
        job_do_finalize_locked(job);
1054
    }
1055
}
1056

1057
/* Called with job_mutex held. */
1058
static void job_completed_locked(Job *job)
1059
{
1060
    assert(job && job->txn && !job_is_completed_locked(job));
1061

1062
    job_update_rc_locked(job);
1063
    trace_job_completed(job, job->ret);
1064
    if (job->ret) {
1065
        job_completed_txn_abort_locked(job);
1066
    } else {
1067
        job_completed_txn_success_locked(job);
1068
    }
1069
}
1070

1071
/**
1072
 * Useful only as a type shim for aio_bh_schedule_oneshot.
1073
 * Called with job_mutex *not* held.
1074
 */
1075
static void job_exit(void *opaque)
1076
{
1077
    Job *job = (Job *)opaque;
1078
    JOB_LOCK_GUARD();
1079
    job_ref_locked(job);
1080

1081
    /* This is a lie, we're not quiescent, but still doing the completion
1082
     * callbacks. However, completion callbacks tend to involve operations that
1083
     * drain block nodes, and if .drained_poll still returned true, we would
1084
     * deadlock. */
1085
    job->busy = false;
1086
    job_event_idle_locked(job);
1087

1088
    job_completed_locked(job);
1089
    job_unref_locked(job);
1090
}
1091

1092
/**
1093
 * All jobs must allow a pause point before entering their job proper. This
1094
 * ensures that jobs can be paused prior to being started, then resumed later.
1095
 */
1096
static void coroutine_fn job_co_entry(void *opaque)
1097
{
1098
    Job *job = opaque;
1099
    int ret;
1100

1101
    assert(job && job->driver && job->driver->run);
1102
    WITH_JOB_LOCK_GUARD() {
1103
        assert(job->aio_context == qemu_get_current_aio_context());
1104
        job_pause_point_locked(job);
1105
    }
1106
    ret = job->driver->run(job, &job->err);
1107
    WITH_JOB_LOCK_GUARD() {
1108
        job->ret = ret;
1109
        job->deferred_to_main_loop = true;
1110
        job->busy = true;
1111
    }
1112
    aio_bh_schedule_oneshot(qemu_get_aio_context(), job_exit, job);
1113
}
1114

1115
void job_start(Job *job)
1116
{
1117
    assert(qemu_in_main_thread());
1118

1119
    WITH_JOB_LOCK_GUARD() {
1120
        assert(job && !job_started_locked(job) && job->paused &&
1121
            job->driver && job->driver->run);
1122
        job->co = qemu_coroutine_create(job_co_entry, job);
1123
        job->pause_count--;
1124
        job->busy = true;
1125
        job->paused = false;
1126
        job_state_transition_locked(job, JOB_STATUS_RUNNING);
1127
    }
1128
    aio_co_enter(job->aio_context, job->co);
1129
}
1130

1131
void job_cancel_locked(Job *job, bool force)
1132
{
1133
    if (job->status == JOB_STATUS_CONCLUDED) {
1134
        job_do_dismiss_locked(job);
1135
        return;
1136
    }
1137
    job_cancel_async_locked(job, force);
1138
    if (!job_started_locked(job)) {
1139
        job_completed_locked(job);
1140
    } else if (job->deferred_to_main_loop) {
1141
        /*
1142
         * job_cancel_async() ignores soft-cancel requests for jobs
1143
         * that are already done (i.e. deferred to the main loop).  We
1144
         * have to check again whether the job is really cancelled.
1145
         * (job_cancel_requested() and job_is_cancelled() are equivalent
1146
         * here, because job_cancel_async() will make soft-cancel
1147
         * requests no-ops when deferred_to_main_loop is true.  We
1148
         * choose to call job_is_cancelled() to show that we invoke
1149
         * job_completed_txn_abort() only for force-cancelled jobs.)
1150
         */
1151
        if (job_is_cancelled_locked(job)) {
1152
            job_completed_txn_abort_locked(job);
1153
        }
1154
    } else {
1155
        job_enter_cond_locked(job, NULL);
1156
    }
1157
}
1158

1159
void job_user_cancel_locked(Job *job, bool force, Error **errp)
1160
{
1161
    if (job_apply_verb_locked(job, JOB_VERB_CANCEL, errp)) {
1162
        return;
1163
    }
1164
    job_cancel_locked(job, force);
1165
}
1166

1167
/* A wrapper around job_cancel_locked() taking an Error ** parameter so it may
1168
 * be used with job_finish_sync_locked() without the need for (rather nasty)
1169
 * function pointer casts there.
1170
 *
1171
 * Called with job_mutex held.
1172
 */
1173
static void job_cancel_err_locked(Job *job, Error **errp)
1174
{
1175
    job_cancel_locked(job, false);
1176
}
1177

1178
/**
1179
 * Same as job_cancel_err(), but force-cancel.
1180
 * Called with job_mutex held.
1181
 */
1182
static void job_force_cancel_err_locked(Job *job, Error **errp)
1183
{
1184
    job_cancel_locked(job, true);
1185
}
1186

1187
int job_cancel_sync_locked(Job *job, bool force)
1188
{
1189
    if (force) {
1190
        return job_finish_sync_locked(job, &job_force_cancel_err_locked, NULL);
1191
    } else {
1192
        return job_finish_sync_locked(job, &job_cancel_err_locked, NULL);
1193
    }
1194
}
1195

1196
int job_cancel_sync(Job *job, bool force)
1197
{
1198
    JOB_LOCK_GUARD();
1199
    return job_cancel_sync_locked(job, force);
1200
}
1201

1202
void job_cancel_sync_all(void)
1203
{
1204
    Job *job;
1205
    JOB_LOCK_GUARD();
1206

1207
    while ((job = job_next_locked(NULL))) {
1208
        job_cancel_sync_locked(job, true);
1209
    }
1210
}
1211

1212
int job_complete_sync_locked(Job *job, Error **errp)
1213
{
1214
    return job_finish_sync_locked(job, job_complete_locked, errp);
1215
}
1216

1217
void job_complete_locked(Job *job, Error **errp)
1218
{
1219
    /* Should not be reachable via external interface for internal jobs */
1220
    assert(job->id);
1221
    GLOBAL_STATE_CODE();
1222
    if (job_apply_verb_locked(job, JOB_VERB_COMPLETE, errp)) {
1223
        return;
1224
    }
1225
    if (job_cancel_requested_locked(job) || !job->driver->complete) {
1226
        error_setg(errp, "The active block job '%s' cannot be completed",
1227
                   job->id);
1228
        return;
1229
    }
1230

1231
    job_unlock();
1232
    job->driver->complete(job, errp);
1233
    job_lock();
1234
}
1235

1236
int job_finish_sync_locked(Job *job,
1237
                           void (*finish)(Job *, Error **errp),
1238
                           Error **errp)
1239
{
1240
    Error *local_err = NULL;
1241
    int ret;
1242
    GLOBAL_STATE_CODE();
1243

1244
    job_ref_locked(job);
1245

1246
    if (finish) {
1247
        finish(job, &local_err);
1248
    }
1249
    if (local_err) {
1250
        error_propagate(errp, local_err);
1251
        job_unref_locked(job);
1252
        return -EBUSY;
1253
    }
1254

1255
    job_unlock();
1256
    AIO_WAIT_WHILE_UNLOCKED(job->aio_context,
1257
                            (job_enter(job), !job_is_completed(job)));
1258
    job_lock();
1259

1260
    ret = (job_is_cancelled_locked(job) && job->ret == 0)
1261
          ? -ECANCELED : job->ret;
1262
    job_unref_locked(job);
1263
    return ret;
1264
}
1265