blockjob.c

   1 /*
   2  * QEMU System Emulator block driver
   3  *
   4  * Copyright (c) 2011 IBM Corp.
   5  * Copyright (c) 2012 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 "qemu-common.h"
  28 #include "block/block.h"
  29 #include "block/blockjob_int.h"
  30 #include "block/block_int.h"
  31 #include "sysemu/block-backend.h"
  32 #include "qapi/qmp/qerror.h"
  33 #include "qapi/qmp/qjson.h"
  34 #include "qemu/coroutine.h"
  35 #include "qemu/id.h"
  36 #include "qmp-commands.h"
  37 #include "qemu/timer.h"
  38 #include "qapi-event.h"
  39
  40 static void block_job_event_cancelled(BlockJob *job);
  41 static void block_job_event_completed(BlockJob *job, const char *msg);
  42
  43 /* Transactional group of block jobs */
  44 struct BlockJobTxn {
  45
  46     /* Is this txn being cancelled? */
  47     bool aborting;
  48
  49     /* List of jobs */
  50     QLIST_HEAD(, BlockJob) jobs;
  51
  52     /* Reference count */
  53     int refcnt;
  54 };
  55
  56 static QLIST_HEAD(, BlockJob) block_jobs = QLIST_HEAD_INITIALIZER(block_jobs);
  57
  58 /*
  59  * The block job API is composed of two categories of functions.
  60  *
  61  * The first includes functions used by the monitor.  The monitor is
  62  * peculiar in that it accesses the block job list with block_job_get, and
  63  * therefore needs consistency across block_job_get and the actual operation
  64  * (e.g. block_job_set_speed).  The consistency is achieved with
  65  * aio_context_acquire/release.  These functions are declared in blockjob.h.
  66  *
  67  * The second includes functions used by the block job drivers and sometimes
  68  * by the core block layer.  These do not care about locking, because the
  69  * whole coroutine runs under the AioContext lock, and are declared in
  70  * blockjob_int.h.
  71  */
  72
  73 BlockJob *block_job_next(BlockJob *job)
  74 {
  75     if (!job) {
  76         return QLIST_FIRST(&block_jobs);
  77     }
  78     return QLIST_NEXT(job, job_list);
  79 }
  80
  81 BlockJob *block_job_get(const char *id)
  82 {
  83     BlockJob *job;
  84
  85     QLIST_FOREACH(job, &block_jobs, job_list) {
  86         if (job->id && !strcmp(id, job->id)) {
  87             return job;
  88         }
  89     }
  90
  91     return NULL;
  92 }
  93
  94 BlockJobTxn *block_job_txn_new(void)
  95 {
  96     BlockJobTxn *txn = g_new0(BlockJobTxn, 1);
  97     QLIST_INIT(&txn->jobs);
  98     txn->refcnt = 1;
  99     return txn;
 100 }
 101
 102 static void block_job_txn_ref(BlockJobTxn *txn)
 103 {
 104     txn->refcnt++;
 105 }
 106
 107 void block_job_txn_unref(BlockJobTxn *txn)
 108 {
 109     if (txn && --txn->refcnt == 0) {
 110         g_free(txn);
 111     }
 112 }
 113
 114 void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job)
 115 {
 116     if (!txn) {
 117         return;
 118     }
 119
 120     assert(!job->txn);
 121     job->txn = txn;
 122
 123     QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
 124     block_job_txn_ref(txn);
 125 }
 126
 127 static void block_job_pause(BlockJob *job)
 128 {
 129     job->pause_count++;
 130 }
 131
 132 static void block_job_resume(BlockJob *job)
 133 {
 134     assert(job->pause_count > 0);
 135     job->pause_count--;
 136     if (job->pause_count) {
 137         return;
 138     }
 139     block_job_enter(job);
 140 }
 141
 142 static void block_job_ref(BlockJob *job)
 143 {
 144     ++job->refcnt;
 145 }
 146
 147 static void block_job_attached_aio_context(AioContext *new_context,
 148                                            void *opaque);
 149 static void block_job_detach_aio_context(void *opaque);
 150
 151 static void block_job_unref(BlockJob *job)
 152 {
 153     if (--job->refcnt == 0) {
 154         BlockDriverState *bs = blk_bs(job->blk);
 155         bs->job = NULL;
 156         block_job_remove_all_bdrv(job);
 157         blk_remove_aio_context_notifier(job->blk,
 158                                         block_job_attached_aio_context,
 159                                         block_job_detach_aio_context, job);
 160         blk_unref(job->blk);
 161         error_free(job->blocker);
 162         g_free(job->id);
 163         QLIST_REMOVE(job, job_list);
 164         g_free(job);
 165     }
 166 }
 167
 168 static void block_job_attached_aio_context(AioContext *new_context,
 169                                            void *opaque)
 170 {
 171     BlockJob *job = opaque;
 172
 173     if (job->driver->attached_aio_context) {
 174         job->driver->attached_aio_context(job, new_context);
 175     }
 176
 177     block_job_resume(job);
 178 }
 179
 180 static void block_job_drain(BlockJob *job)
 181 {
 182     /* If job is !job->busy this kicks it into the next pause point. */
 183     block_job_enter(job);
 184
 185     blk_drain(job->blk);
 186     if (job->driver->drain) {
 187         job->driver->drain(job);
 188     }
 189 }
 190
 191 static void block_job_detach_aio_context(void *opaque)
 192 {
 193     BlockJob *job = opaque;
 194
 195     /* In case the job terminates during aio_poll()... */
 196     block_job_ref(job);
 197
 198     block_job_pause(job);
 199
 200     while (!job->paused && !job->completed) {
 201         block_job_drain(job);
 202     }
 203
 204     block_job_unref(job);
 205 }
 206
 207 static char *child_job_get_parent_desc(BdrvChild *c)
 208 {
 209     BlockJob *job = c->opaque;
 210     return g_strdup_printf("%s job '%s'",
 211                            BlockJobType_lookup[job->driver->job_type],
 212                            job->id);
 213 }
 214
 215 static const BdrvChildRole child_job = {
 216     .get_parent_desc    = child_job_get_parent_desc,
 217     .stay_at_node       = true,
 218 };
 219
 220 static void block_job_drained_begin(void *opaque)
 221 {
 222     BlockJob *job = opaque;
 223     block_job_pause(job);
 224 }
 225
 226 static void block_job_drained_end(void *opaque)
 227 {
 228     BlockJob *job = opaque;
 229     block_job_resume(job);
 230 }
 231
 232 static const BlockDevOps block_job_dev_ops = {
 233     .drained_begin = block_job_drained_begin,
 234     .drained_end = block_job_drained_end,
 235 };
 236
 237 void block_job_remove_all_bdrv(BlockJob *job)
 238 {
 239     GSList *l;
 240     for (l = job->nodes; l; l = l->next) {
 241         BdrvChild *c = l->data;
 242         bdrv_op_unblock_all(c->bs, job->blocker);
 243         bdrv_root_unref_child(c);
 244     }
 245     g_slist_free(job->nodes);
 246     job->nodes = NULL;
 247 }
 248
 249 int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
 250                        uint64_t perm, uint64_t shared_perm, Error **errp)
 251 {
 252     BdrvChild *c;
 253
 254     c = bdrv_root_attach_child(bs, name, &child_job, perm, shared_perm,
 255                                job, errp);
 256     if (c == NULL) {
 257         return -EPERM;
 258     }
 259
 260     job->nodes = g_slist_prepend(job->nodes, c);
 261     bdrv_ref(bs);
 262     bdrv_op_block_all(bs, job->blocker);
 263
 264     return 0;
 265 }
 266
 267 bool block_job_is_internal(BlockJob *job)
 268 {
 269     return (job->id == NULL);
 270 }
 271
 272 static bool block_job_started(BlockJob *job)
 273 {
 274     return job->co;
 275 }
 276
 277 /**
 278  * All jobs must allow a pause point before entering their job proper. This
 279  * ensures that jobs can be paused prior to being started, then resumed later.
 280  */
 281 static void coroutine_fn block_job_co_entry(void *opaque)
 282 {
 283     BlockJob *job = opaque;
 284
 285     assert(job && job->driver && job->driver->start);
 286     block_job_pause_point(job);
 287     job->driver->start(job);
 288 }
 289
 290 void block_job_start(BlockJob *job)
 291 {
 292     assert(job && !block_job_started(job) && job->paused &&
 293            job->driver && job->driver->start);
 294     job->co = qemu_coroutine_create(block_job_co_entry, job);
 295     job->pause_count--;
 296     job->busy = true;
 297     job->paused = false;
 298     bdrv_coroutine_enter(blk_bs(job->blk), job->co);
 299 }
 300
 301 static void block_job_completed_single(BlockJob *job)
 302 {
 303     assert(job->completed);
 304
 305     if (!job->ret) {
 306         if (job->driver->commit) {
 307             job->driver->commit(job);
 308         }
 309     } else {
 310         if (job->driver->abort) {
 311             job->driver->abort(job);
 312         }
 313     }
 314     if (job->driver->clean) {
 315         job->driver->clean(job);
 316     }
 317
 318     if (job->cb) {
 319         job->cb(job->opaque, job->ret);
 320     }
 321
 322     /* Emit events only if we actually started */
 323     if (block_job_started(job)) {
 324         if (block_job_is_cancelled(job)) {
 325             block_job_event_cancelled(job);
 326         } else {
 327             const char *msg = NULL;
 328             if (job->ret < 0) {
 329                 msg = strerror(-job->ret);
 330             }
 331             block_job_event_completed(job, msg);
 332         }
 333     }
 334
 335     if (job->txn) {
 336         QLIST_REMOVE(job, txn_list);
 337         block_job_txn_unref(job->txn);
 338     }
 339     block_job_unref(job);
 340 }
 341
 342 static void block_job_cancel_async(BlockJob *job)
 343 {
 344     if (job->iostatus != BLOCK_DEVICE_IO_STATUS_OK) {
 345         block_job_iostatus_reset(job);
 346     }
 347     if (job->user_paused) {
 348         /* Do not call block_job_enter here, the caller will handle it.  */
 349         job->user_paused = false;
 350         job->pause_count--;
 351     }
 352     job->cancelled = true;
 353 }
 354
 355 static int block_job_finish_sync(BlockJob *job,
 356                                  void (*finish)(BlockJob *, Error **errp),
 357                                  Error **errp)
 358 {
 359     Error *local_err = NULL;
 360     int ret;
 361
 362     assert(blk_bs(job->blk)->job == job);
 363
 364     block_job_ref(job);
 365
 366     if (finish) {
 367         finish(job, &local_err);
 368     }
 369     if (local_err) {
 370         error_propagate(errp, local_err);
 371         block_job_unref(job);
 372         return -EBUSY;
 373     }
 374     /* block_job_drain calls block_job_enter, and it should be enough to
 375      * induce progress until the job completes or moves to the main thread.
 376     */
 377     while (!job->deferred_to_main_loop && !job->completed) {
 378         block_job_drain(job);
 379     }
 380     while (!job->completed) {
 381         aio_poll(qemu_get_aio_context(), true);
 382     }
 383     ret = (job->cancelled && job->ret == 0) ? -ECANCELED : job->ret;
 384     block_job_unref(job);
 385     return ret;
 386 }
 387
 388 static void block_job_completed_txn_abort(BlockJob *job)
 389 {
 390     AioContext *ctx;
 391     BlockJobTxn *txn = job->txn;
 392     BlockJob *other_job;
 393
 394     if (txn->aborting) {
 395         /*
 396          * We are cancelled by another job, which will handle everything.
 397          */
 398         return;
 399     }
 400     txn->aborting = true;
 401     block_job_txn_ref(txn);
 402
 403     /* We are the first failed job. Cancel other jobs. */
 404     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
 405         ctx = blk_get_aio_context(other_job->blk);
 406         aio_context_acquire(ctx);
 407     }
 408
 409     /* Other jobs are effectively cancelled by us, set the status for
 410      * them; this job, however, may or may not be cancelled, depending
 411      * on the caller, so leave it. */
 412     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
 413         if (other_job != job) {
 414             block_job_cancel_async(other_job);
 415         }
 416     }
 417     while (!QLIST_EMPTY(&txn->jobs)) {
 418         other_job = QLIST_FIRST(&txn->jobs);
 419         ctx = blk_get_aio_context(other_job->blk);
 420         if (!other_job->completed) {
 421             assert(other_job->cancelled);
 422             block_job_finish_sync(other_job, NULL, NULL);
 423         }
 424         block_job_completed_single(other_job);
 425         aio_context_release(ctx);
 426     }
 427
 428     block_job_txn_unref(txn);
 429 }
 430
 431 static void block_job_completed_txn_success(BlockJob *job)
 432 {
 433     AioContext *ctx;
 434     BlockJobTxn *txn = job->txn;
 435     BlockJob *other_job, *next;
 436     /*
 437      * Successful completion, see if there are other running jobs in this
 438      * txn.
 439      */
 440     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
 441         if (!other_job->completed) {
 442             return;
 443         }
 444     }
 445     /* We are the last completed job, commit the transaction. */
 446     QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
 447         ctx = blk_get_aio_context(other_job->blk);
 448         aio_context_acquire(ctx);
 449         assert(other_job->ret == 0);
 450         block_job_completed_single(other_job);
 451         aio_context_release(ctx);
 452     }
 453 }
 454
 455 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
 456 {
 457     Error *local_err = NULL;
 458
 459     if (!job->driver->set_speed) {
 460         error_setg(errp, QERR_UNSUPPORTED);
 461         return;
 462     }
 463     job->driver->set_speed(job, speed, &local_err);
 464     if (local_err) {
 465         error_propagate(errp, local_err);
 466         return;
 467     }
 468
 469     job->speed = speed;
 470 }
 471
 472 void block_job_complete(BlockJob *job, Error **errp)
 473 {
 474     /* Should not be reachable via external interface for internal jobs */
 475     assert(job->id);
 476     if (job->pause_count || job->cancelled ||
 477         !block_job_started(job) || !job->driver->complete) {
 478         error_setg(errp, "The active block job '%s' cannot be completed",
 479                    job->id);
 480         return;
 481     }
 482
 483     job->driver->complete(job, errp);
 484 }
 485
 486 void block_job_user_pause(BlockJob *job)
 487 {
 488     job->user_paused = true;
 489     block_job_pause(job);
 490 }
 491
 492 bool block_job_user_paused(BlockJob *job)
 493 {
 494     return job->user_paused;
 495 }
 496
 497 void block_job_user_resume(BlockJob *job)
 498 {
 499     if (job && job->user_paused && job->pause_count > 0) {
 500         block_job_iostatus_reset(job);
 501         job->user_paused = false;
 502         block_job_resume(job);
 503     }
 504 }
 505
 506 void block_job_cancel(BlockJob *job)
 507 {
 508     if (block_job_started(job)) {
 509         block_job_cancel_async(job);
 510         block_job_enter(job);
 511     } else {
 512         block_job_completed(job, -ECANCELED);
 513     }
 514 }
 515
 516 /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be
 517  * used with block_job_finish_sync() without the need for (rather nasty)
 518  * function pointer casts there. */
 519 static void block_job_cancel_err(BlockJob *job, Error **errp)
 520 {
 521     block_job_cancel(job);
 522 }
 523
 524 int block_job_cancel_sync(BlockJob *job)
 525 {
 526     return block_job_finish_sync(job, &block_job_cancel_err, NULL);
 527 }
 528
 529 void block_job_cancel_sync_all(void)
 530 {
 531     BlockJob *job;
 532     AioContext *aio_context;
 533
 534     while ((job = QLIST_FIRST(&block_jobs))) {
 535         aio_context = blk_get_aio_context(job->blk);
 536         aio_context_acquire(aio_context);
 537         block_job_cancel_sync(job);
 538         aio_context_release(aio_context);
 539     }
 540 }
 541
 542 int block_job_complete_sync(BlockJob *job, Error **errp)
 543 {
 544     return block_job_finish_sync(job, &block_job_complete, errp);
 545 }
 546
 547 BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
 548 {
 549     BlockJobInfo *info;
 550
 551     if (block_job_is_internal(job)) {
 552         error_setg(errp, "Cannot query QEMU internal jobs");
 553         return NULL;
 554     }
 555     info = g_new0(BlockJobInfo, 1);
 556     info->type      = g_strdup(BlockJobType_lookup[job->driver->job_type]);
 557     info->device    = g_strdup(job->id);
 558     info->len       = job->len;
 559     info->busy      = job->busy;
 560     info->paused    = job->pause_count > 0;
 561     info->offset    = job->offset;
 562     info->speed     = job->speed;
 563     info->io_status = job->iostatus;
 564     info->ready     = job->ready;
 565     return info;
 566 }
 567
 568 static void block_job_iostatus_set_err(BlockJob *job, int error)
 569 {
 570     if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
 571         job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
 572                                           BLOCK_DEVICE_IO_STATUS_FAILED;
 573     }
 574 }
 575
 576 static void block_job_event_cancelled(BlockJob *job)
 577 {
 578     if (block_job_is_internal(job)) {
 579         return;
 580     }
 581
 582     qapi_event_send_block_job_cancelled(job->driver->job_type,
 583                                         job->id,
 584                                         job->len,
 585                                         job->offset,
 586                                         job->speed,
 587                                         &error_abort);
 588 }
 589
 590 static void block_job_event_completed(BlockJob *job, const char *msg)
 591 {
 592     if (block_job_is_internal(job)) {
 593         return;
 594     }
 595
 596     qapi_event_send_block_job_completed(job->driver->job_type,
 597                                         job->id,
 598                                         job->len,
 599                                         job->offset,
 600                                         job->speed,
 601                                         !!msg,
 602                                         msg,
 603                                         &error_abort);
 604 }
 605
 606 /*
 607  * API for block job drivers and the block layer.  These functions are
 608  * declared in blockjob_int.h.
 609  */
 610
 611 void *block_job_create(const char *job_id, const BlockJobDriver *driver,
 612                        BlockDriverState *bs, uint64_t perm,
 613                        uint64_t shared_perm, int64_t speed, int flags,
 614                        BlockCompletionFunc *cb, void *opaque, Error **errp)
 615 {
 616     BlockBackend *blk;
 617     BlockJob *job;
 618     int ret;
 619
 620     if (bs->job) {
 621         error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
 622         return NULL;
 623     }
 624
 625     if (job_id == NULL && !(flags & BLOCK_JOB_INTERNAL)) {
 626         job_id = bdrv_get_device_name(bs);
 627         if (!*job_id) {
 628             error_setg(errp, "An explicit job ID is required for this node");
 629             return NULL;
 630         }
 631     }
 632
 633     if (job_id) {
 634         if (flags & BLOCK_JOB_INTERNAL) {
 635             error_setg(errp, "Cannot specify job ID for internal block job");
 636             return NULL;
 637         }
 638
 639         if (!id_wellformed(job_id)) {
 640             error_setg(errp, "Invalid job ID '%s'", job_id);
 641             return NULL;
 642         }
 643
 644         if (block_job_get(job_id)) {
 645             error_setg(errp, "Job ID '%s' already in use", job_id);
 646             return NULL;
 647         }
 648     }
 649
 650     blk = blk_new(perm, shared_perm);
 651     ret = blk_insert_bs(blk, bs, errp);
 652     if (ret < 0) {
 653         blk_unref(blk);
 654         return NULL;
 655     }
 656
 657     job = g_malloc0(driver->instance_size);
 658     job->driver        = driver;
 659     job->id            = g_strdup(job_id);
 660     job->blk           = blk;
 661     job->cb            = cb;
 662     job->opaque        = opaque;
 663     job->busy          = false;
 664     job->paused        = true;
 665     job->pause_count   = 1;
 666     job->refcnt        = 1;
 667
 668     error_setg(&job->blocker, "block device is in use by block job: %s",
 669                BlockJobType_lookup[driver->job_type]);
 670     block_job_add_bdrv(job, "main node", bs, 0, BLK_PERM_ALL, &error_abort);
 671     bs->job = job;
 672
 673     blk_set_dev_ops(blk, &block_job_dev_ops, job);
 674     bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
 675
 676     QLIST_INSERT_HEAD(&block_jobs, job, job_list);
 677
 678     blk_add_aio_context_notifier(blk, block_job_attached_aio_context,
 679                                  block_job_detach_aio_context, job);
 680
 681     /* Only set speed when necessary to avoid NotSupported error */
 682     if (speed != 0) {
 683         Error *local_err = NULL;
 684
 685         block_job_set_speed(job, speed, &local_err);
 686         if (local_err) {
 687             block_job_unref(job);
 688             error_propagate(errp, local_err);
 689             return NULL;
 690         }
 691     }
 692     return job;
 693 }
 694
 695 void block_job_pause_all(void)
 696 {
 697     BlockJob *job = NULL;
 698     while ((job = block_job_next(job))) {
 699         AioContext *aio_context = blk_get_aio_context(job->blk);
 700
 701         aio_context_acquire(aio_context);
 702         block_job_pause(job);
 703         aio_context_release(aio_context);
 704     }
 705 }
 706
 707 void block_job_early_fail(BlockJob *job)
 708 {
 709     block_job_unref(job);
 710 }
 711
 712 void block_job_completed(BlockJob *job, int ret)
 713 {
 714     assert(blk_bs(job->blk)->job == job);
 715     assert(!job->completed);
 716     job->completed = true;
 717     job->ret = ret;
 718     if (!job->txn) {
 719         block_job_completed_single(job);
 720     } else if (ret < 0 || block_job_is_cancelled(job)) {
 721         block_job_completed_txn_abort(job);
 722     } else {
 723         block_job_completed_txn_success(job);
 724     }
 725 }
 726
 727 static bool block_job_should_pause(BlockJob *job)
 728 {
 729     return job->pause_count > 0;
 730 }
 731
 732 void coroutine_fn block_job_pause_point(BlockJob *job)
 733 {
 734     assert(job && block_job_started(job));
 735
 736     if (!block_job_should_pause(job)) {
 737         return;
 738     }
 739     if (block_job_is_cancelled(job)) {
 740         return;
 741     }
 742
 743     if (job->driver->pause) {
 744         job->driver->pause(job);
 745     }
 746
 747     if (block_job_should_pause(job) && !block_job_is_cancelled(job)) {
 748         job->paused = true;
 749         job->busy = false;
 750         qemu_coroutine_yield(); /* wait for block_job_resume() */
 751         job->busy = true;
 752         job->paused = false;
 753     }
 754
 755     if (job->driver->resume) {
 756         job->driver->resume(job);
 757     }
 758 }
 759
 760 void block_job_resume_all(void)
 761 {
 762     BlockJob *job = NULL;
 763     while ((job = block_job_next(job))) {
 764         AioContext *aio_context = blk_get_aio_context(job->blk);
 765
 766         aio_context_acquire(aio_context);
 767         block_job_resume(job);
 768         aio_context_release(aio_context);
 769     }
 770 }
 771
 772 void block_job_enter(BlockJob *job)
 773 {
 774     if (!block_job_started(job)) {
 775         return;
 776     }
 777     if (job->deferred_to_main_loop) {
 778         return;
 779     }
 780
 781     if (!job->busy) {
 782         bdrv_coroutine_enter(blk_bs(job->blk), job->co);
 783     }
 784 }
 785
 786 bool block_job_is_cancelled(BlockJob *job)
 787 {
 788     return job->cancelled;
 789 }
 790
 791 void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
 792 {
 793     assert(job->busy);
 794
 795     /* Check cancellation *before* setting busy = false, too!  */
 796     if (block_job_is_cancelled(job)) {
 797         return;
 798     }
 799
 800     job->busy = false;
 801     if (!block_job_should_pause(job)) {
 802         co_aio_sleep_ns(blk_get_aio_context(job->blk), type, ns);
 803     }
 804     job->busy = true;
 805
 806     block_job_pause_point(job);
 807 }
 808
 809 void block_job_yield(BlockJob *job)
 810 {
 811     assert(job->busy);
 812
 813     /* Check cancellation *before* setting busy = false, too!  */
 814     if (block_job_is_cancelled(job)) {
 815         return;
 816     }
 817
 818     job->busy = false;
 819     if (!block_job_should_pause(job)) {
 820         qemu_coroutine_yield();
 821     }
 822     job->busy = true;
 823
 824     block_job_pause_point(job);
 825 }
 826
 827 void block_job_iostatus_reset(BlockJob *job)
 828 {
 829     if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
 830         return;
 831     }
 832     assert(job->user_paused && job->pause_count > 0);
 833     job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
 834 }
 835
 836 void block_job_event_ready(BlockJob *job)
 837 {
 838     job->ready = true;
 839
 840     if (block_job_is_internal(job)) {
 841         return;
 842     }
 843
 844     qapi_event_send_block_job_ready(job->driver->job_type,
 845                                     job->id,
 846                                     job->len,
 847                                     job->offset,
 848                                     job->speed, &error_abort);
 849 }
 850
 851 BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 852                                         int is_read, int error)
 853 {
 854     BlockErrorAction action;
 855
 856     switch (on_err) {
 857     case BLOCKDEV_ON_ERROR_ENOSPC:
 858     case BLOCKDEV_ON_ERROR_AUTO:
 859         action = (error == ENOSPC) ?
 860                  BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
 861         break;
 862     case BLOCKDEV_ON_ERROR_STOP:
 863         action = BLOCK_ERROR_ACTION_STOP;
 864         break;
 865     case BLOCKDEV_ON_ERROR_REPORT:
 866         action = BLOCK_ERROR_ACTION_REPORT;
 867         break;
 868     case BLOCKDEV_ON_ERROR_IGNORE:
 869         action = BLOCK_ERROR_ACTION_IGNORE;
 870         break;
 871     default:
 872         abort();
 873     }
 874     if (!block_job_is_internal(job)) {
 875         qapi_event_send_block_job_error(job->id,
 876                                         is_read ? IO_OPERATION_TYPE_READ :
 877                                         IO_OPERATION_TYPE_WRITE,
 878                                         action, &error_abort);
 879     }
 880     if (action == BLOCK_ERROR_ACTION_STOP) {
 881         /* make the pause user visible, which will be resumed from QMP. */
 882         block_job_user_pause(job);
 883         block_job_iostatus_set_err(job, error);
 884     }
 885     return action;
 886 }
 887
 888 typedef struct {
 889     BlockJob *job;
 890     AioContext *aio_context;
 891     BlockJobDeferToMainLoopFn *fn;
 892     void *opaque;
 893 } BlockJobDeferToMainLoopData;
 894
 895 static void block_job_defer_to_main_loop_bh(void *opaque)
 896 {
 897     BlockJobDeferToMainLoopData *data = opaque;
 898     AioContext *aio_context;
 899
 900     /* Prevent race with block_job_defer_to_main_loop() */
 901     aio_context_acquire(data->aio_context);
 902
 903     /* Fetch BDS AioContext again, in case it has changed */
 904     aio_context = blk_get_aio_context(data->job->blk);
 905     if (aio_context != data->aio_context) {
 906         aio_context_acquire(aio_context);
 907     }
 908
 909     data->fn(data->job, data->opaque);
 910
 911     if (aio_context != data->aio_context) {
 912         aio_context_release(aio_context);
 913     }
 914
 915     aio_context_release(data->aio_context);
 916
 917     g_free(data);
 918 }
 919
 920 void block_job_defer_to_main_loop(BlockJob *job,
 921                                   BlockJobDeferToMainLoopFn *fn,
 922                                   void *opaque)
 923 {
 924     BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data));
 925     data->job = job;
 926     data->aio_context = blk_get_aio_context(job->blk);
 927     data->fn = fn;
 928     data->opaque = opaque;
 929     job->deferred_to_main_loop = true;
 930
 931     aio_bh_schedule_oneshot(qemu_get_aio_context(),
 932                             block_job_defer_to_main_loop_bh, data);
 933 }