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 "trace.h"
  29 #include "block/block.h"
  30 #include "block/blockjob.h"
  31 #include "block/block_int.h"
  32 #include "sysemu/block-backend.h"
  33 #include "qapi/qmp/qerror.h"
  34 #include "qapi/qmp/qjson.h"
  35 #include "qemu/coroutine.h"
  36 #include "qemu/id.h"
  37 #include "qmp-commands.h"
  38 #include "qemu/timer.h"
  39 #include "qapi-event.h"
  40
  41 /* Transactional group of block jobs */
  42 struct BlockJobTxn {
  43
  44     /* Is this txn being cancelled? */
  45     bool aborting;
  46
  47     /* List of jobs */
  48     QLIST_HEAD(, BlockJob) jobs;
  49
  50     /* Reference count */
  51     int refcnt;
  52 };
  53
  54 static QLIST_HEAD(, BlockJob) block_jobs = QLIST_HEAD_INITIALIZER(block_jobs);
  55
  56 BlockJob *block_job_next(BlockJob *job)
  57 {
  58     if (!job) {
  59         return QLIST_FIRST(&block_jobs);
  60     }
  61     return QLIST_NEXT(job, job_list);
  62 }
  63
  64 BlockJob *block_job_get(const char *id)
  65 {
  66     BlockJob *job;
  67
  68     QLIST_FOREACH(job, &block_jobs, job_list) {
  69         if (!strcmp(id, job->id)) {
  70             return job;
  71         }
  72     }
  73
  74     return NULL;
  75 }
  76
  77 /* Normally the job runs in its BlockBackend's AioContext.  The exception is
  78  * block_job_defer_to_main_loop() where it runs in the QEMU main loop.  Code
  79  * that supports both cases uses this helper function.
  80  */
  81 static AioContext *block_job_get_aio_context(BlockJob *job)
  82 {
  83     return job->deferred_to_main_loop ?
  84            qemu_get_aio_context() :
  85            blk_get_aio_context(job->blk);
  86 }
  87
  88 static void block_job_attached_aio_context(AioContext *new_context,
  89                                            void *opaque)
  90 {
  91     BlockJob *job = opaque;
  92
  93     if (job->driver->attached_aio_context) {
  94         job->driver->attached_aio_context(job, new_context);
  95     }
  96
  97     block_job_resume(job);
  98 }
  99
 100 static void block_job_detach_aio_context(void *opaque)
 101 {
 102     BlockJob *job = opaque;
 103
 104     /* In case the job terminates during aio_poll()... */
 105     block_job_ref(job);
 106
 107     block_job_pause(job);
 108
 109     if (!job->paused) {
 110         /* If job is !job->busy this kicks it into the next pause point. */
 111         block_job_enter(job);
 112     }
 113     while (!job->paused && !job->completed) {
 114         aio_poll(block_job_get_aio_context(job), true);
 115     }
 116
 117     block_job_unref(job);
 118 }
 119
 120 void *block_job_create(const char *job_id, const BlockJobDriver *driver,
 121                        BlockDriverState *bs, int64_t speed,
 122                        BlockCompletionFunc *cb, void *opaque, Error **errp)
 123 {
 124     BlockBackend *blk;
 125     BlockJob *job;
 126
 127     assert(cb);
 128     if (bs->job) {
 129         error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
 130         return NULL;
 131     }
 132
 133     if (job_id == NULL) {
 134         job_id = bdrv_get_device_name(bs);
 135     }
 136
 137     if (!id_wellformed(job_id)) {
 138         error_setg(errp, "Invalid job ID '%s'", job_id);
 139         return NULL;
 140     }
 141
 142     if (block_job_get(job_id)) {
 143         error_setg(errp, "Job ID '%s' already in use", job_id);
 144         return NULL;
 145     }
 146
 147     blk = blk_new();
 148     blk_insert_bs(blk, bs);
 149
 150     job = g_malloc0(driver->instance_size);
 151     error_setg(&job->blocker, "block device is in use by block job: %s",
 152                BlockJobType_lookup[driver->job_type]);
 153     bdrv_op_block_all(bs, job->blocker);
 154     bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
 155
 156     job->driver        = driver;
 157     job->id            = g_strdup(job_id);
 158     job->blk           = blk;
 159     job->cb            = cb;
 160     job->opaque        = opaque;
 161     job->busy          = true;
 162     job->refcnt        = 1;
 163     bs->job = job;
 164
 165     QLIST_INSERT_HEAD(&block_jobs, job, job_list);
 166
 167     blk_add_aio_context_notifier(blk, block_job_attached_aio_context,
 168                                  block_job_detach_aio_context, job);
 169
 170     /* Only set speed when necessary to avoid NotSupported error */
 171     if (speed != 0) {
 172         Error *local_err = NULL;
 173
 174         block_job_set_speed(job, speed, &local_err);
 175         if (local_err) {
 176             block_job_unref(job);
 177             error_propagate(errp, local_err);
 178             return NULL;
 179         }
 180     }
 181     return job;
 182 }
 183
 184 void block_job_ref(BlockJob *job)
 185 {
 186     ++job->refcnt;
 187 }
 188
 189 void block_job_unref(BlockJob *job)
 190 {
 191     if (--job->refcnt == 0) {
 192         BlockDriverState *bs = blk_bs(job->blk);
 193         bs->job = NULL;
 194         bdrv_op_unblock_all(bs, job->blocker);
 195         blk_remove_aio_context_notifier(job->blk,
 196                                         block_job_attached_aio_context,
 197                                         block_job_detach_aio_context, job);
 198         blk_unref(job->blk);
 199         error_free(job->blocker);
 200         g_free(job->id);
 201         QLIST_REMOVE(job, job_list);
 202         g_free(job);
 203     }
 204 }
 205
 206 static void block_job_completed_single(BlockJob *job)
 207 {
 208     if (!job->ret) {
 209         if (job->driver->commit) {
 210             job->driver->commit(job);
 211         }
 212     } else {
 213         if (job->driver->abort) {
 214             job->driver->abort(job);
 215         }
 216     }
 217     job->cb(job->opaque, job->ret);
 218     if (job->txn) {
 219         block_job_txn_unref(job->txn);
 220     }
 221     block_job_unref(job);
 222 }
 223
 224 static void block_job_completed_txn_abort(BlockJob *job)
 225 {
 226     AioContext *ctx;
 227     BlockJobTxn *txn = job->txn;
 228     BlockJob *other_job, *next;
 229
 230     if (txn->aborting) {
 231         /*
 232          * We are cancelled by another job, which will handle everything.
 233          */
 234         return;
 235     }
 236     txn->aborting = true;
 237     /* We are the first failed job. Cancel other jobs. */
 238     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
 239         ctx = blk_get_aio_context(other_job->blk);
 240         aio_context_acquire(ctx);
 241     }
 242     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
 243         if (other_job == job || other_job->completed) {
 244             /* Other jobs are "effectively" cancelled by us, set the status for
 245              * them; this job, however, may or may not be cancelled, depending
 246              * on the caller, so leave it. */
 247             if (other_job != job) {
 248                 other_job->cancelled = true;
 249             }
 250             continue;
 251         }
 252         block_job_cancel_sync(other_job);
 253         assert(other_job->completed);
 254     }
 255     QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
 256         ctx = blk_get_aio_context(other_job->blk);
 257         block_job_completed_single(other_job);
 258         aio_context_release(ctx);
 259     }
 260 }
 261
 262 static void block_job_completed_txn_success(BlockJob *job)
 263 {
 264     AioContext *ctx;
 265     BlockJobTxn *txn = job->txn;
 266     BlockJob *other_job, *next;
 267     /*
 268      * Successful completion, see if there are other running jobs in this
 269      * txn.
 270      */
 271     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
 272         if (!other_job->completed) {
 273             return;
 274         }
 275     }
 276     /* We are the last completed job, commit the transaction. */
 277     QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
 278         ctx = blk_get_aio_context(other_job->blk);
 279         aio_context_acquire(ctx);
 280         assert(other_job->ret == 0);
 281         block_job_completed_single(other_job);
 282         aio_context_release(ctx);
 283     }
 284 }
 285
 286 void block_job_completed(BlockJob *job, int ret)
 287 {
 288     assert(blk_bs(job->blk)->job == job);
 289     assert(!job->completed);
 290     job->completed = true;
 291     job->ret = ret;
 292     if (!job->txn) {
 293         block_job_completed_single(job);
 294     } else if (ret < 0 || block_job_is_cancelled(job)) {
 295         block_job_completed_txn_abort(job);
 296     } else {
 297         block_job_completed_txn_success(job);
 298     }
 299 }
 300
 301 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
 302 {
 303     Error *local_err = NULL;
 304
 305     if (!job->driver->set_speed) {
 306         error_setg(errp, QERR_UNSUPPORTED);
 307         return;
 308     }
 309     job->driver->set_speed(job, speed, &local_err);
 310     if (local_err) {
 311         error_propagate(errp, local_err);
 312         return;
 313     }
 314
 315     job->speed = speed;
 316 }
 317
 318 void block_job_complete(BlockJob *job, Error **errp)
 319 {
 320     if (job->pause_count || job->cancelled || !job->driver->complete) {
 321         error_setg(errp, "The active block job '%s' cannot be completed",
 322                    job->id);
 323         return;
 324     }
 325
 326     job->driver->complete(job, errp);
 327 }
 328
 329 void block_job_pause(BlockJob *job)
 330 {
 331     job->pause_count++;
 332 }
 333
 334 static bool block_job_should_pause(BlockJob *job)
 335 {
 336     return job->pause_count > 0;
 337 }
 338
 339 void coroutine_fn block_job_pause_point(BlockJob *job)
 340 {
 341     if (!block_job_should_pause(job)) {
 342         return;
 343     }
 344     if (block_job_is_cancelled(job)) {
 345         return;
 346     }
 347
 348     if (job->driver->pause) {
 349         job->driver->pause(job);
 350     }
 351
 352     if (block_job_should_pause(job) && !block_job_is_cancelled(job)) {
 353         job->paused = true;
 354         job->busy = false;
 355         qemu_coroutine_yield(); /* wait for block_job_resume() */
 356         job->busy = true;
 357         job->paused = false;
 358     }
 359
 360     if (job->driver->resume) {
 361         job->driver->resume(job);
 362     }
 363 }
 364
 365 void block_job_resume(BlockJob *job)
 366 {
 367     assert(job->pause_count > 0);
 368     job->pause_count--;
 369     if (job->pause_count) {
 370         return;
 371     }
 372     block_job_enter(job);
 373 }
 374
 375 void block_job_enter(BlockJob *job)
 376 {
 377     if (job->co && !job->busy) {
 378         qemu_coroutine_enter(job->co);
 379     }
 380 }
 381
 382 void block_job_cancel(BlockJob *job)
 383 {
 384     job->cancelled = true;
 385     block_job_iostatus_reset(job);
 386     block_job_enter(job);
 387 }
 388
 389 bool block_job_is_cancelled(BlockJob *job)
 390 {
 391     return job->cancelled;
 392 }
 393
 394 void block_job_iostatus_reset(BlockJob *job)
 395 {
 396     job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
 397     if (job->driver->iostatus_reset) {
 398         job->driver->iostatus_reset(job);
 399     }
 400 }
 401
 402 static int block_job_finish_sync(BlockJob *job,
 403                                  void (*finish)(BlockJob *, Error **errp),
 404                                  Error **errp)
 405 {
 406     Error *local_err = NULL;
 407     int ret;
 408
 409     assert(blk_bs(job->blk)->job == job);
 410
 411     block_job_ref(job);
 412     finish(job, &local_err);
 413     if (local_err) {
 414         error_propagate(errp, local_err);
 415         block_job_unref(job);
 416         return -EBUSY;
 417     }
 418     while (!job->completed) {
 419         aio_poll(block_job_get_aio_context(job), true);
 420     }
 421     ret = (job->cancelled && job->ret == 0) ? -ECANCELED : job->ret;
 422     block_job_unref(job);
 423     return ret;
 424 }
 425
 426 /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be
 427  * used with block_job_finish_sync() without the need for (rather nasty)
 428  * function pointer casts there. */
 429 static void block_job_cancel_err(BlockJob *job, Error **errp)
 430 {
 431     block_job_cancel(job);
 432 }
 433
 434 int block_job_cancel_sync(BlockJob *job)
 435 {
 436     return block_job_finish_sync(job, &block_job_cancel_err, NULL);
 437 }
 438
 439 void block_job_cancel_sync_all(void)
 440 {
 441     BlockJob *job;
 442     AioContext *aio_context;
 443
 444     while ((job = QLIST_FIRST(&block_jobs))) {
 445         aio_context = blk_get_aio_context(job->blk);
 446         aio_context_acquire(aio_context);
 447         block_job_cancel_sync(job);
 448         aio_context_release(aio_context);
 449     }
 450 }
 451
 452 int block_job_complete_sync(BlockJob *job, Error **errp)
 453 {
 454     return block_job_finish_sync(job, &block_job_complete, errp);
 455 }
 456
 457 void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
 458 {
 459     assert(job->busy);
 460
 461     /* Check cancellation *before* setting busy = false, too!  */
 462     if (block_job_is_cancelled(job)) {
 463         return;
 464     }
 465
 466     job->busy = false;
 467     if (!block_job_should_pause(job)) {
 468         co_aio_sleep_ns(blk_get_aio_context(job->blk), type, ns);
 469     }
 470     job->busy = true;
 471
 472     block_job_pause_point(job);
 473 }
 474
 475 void block_job_yield(BlockJob *job)
 476 {
 477     assert(job->busy);
 478
 479     /* Check cancellation *before* setting busy = false, too!  */
 480     if (block_job_is_cancelled(job)) {
 481         return;
 482     }
 483
 484     job->busy = false;
 485     if (!block_job_should_pause(job)) {
 486         qemu_coroutine_yield();
 487     }
 488     job->busy = true;
 489
 490     block_job_pause_point(job);
 491 }
 492
 493 BlockJobInfo *block_job_query(BlockJob *job)
 494 {
 495     BlockJobInfo *info = g_new0(BlockJobInfo, 1);
 496     info->type      = g_strdup(BlockJobType_lookup[job->driver->job_type]);
 497     info->device    = g_strdup(job->id);
 498     info->len       = job->len;
 499     info->busy      = job->busy;
 500     info->paused    = job->pause_count > 0;
 501     info->offset    = job->offset;
 502     info->speed     = job->speed;
 503     info->io_status = job->iostatus;
 504     info->ready     = job->ready;
 505     return info;
 506 }
 507
 508 static void block_job_iostatus_set_err(BlockJob *job, int error)
 509 {
 510     if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
 511         job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
 512                                           BLOCK_DEVICE_IO_STATUS_FAILED;
 513     }
 514 }
 515
 516 void block_job_event_cancelled(BlockJob *job)
 517 {
 518     qapi_event_send_block_job_cancelled(job->driver->job_type,
 519                                         job->id,
 520                                         job->len,
 521                                         job->offset,
 522                                         job->speed,
 523                                         &error_abort);
 524 }
 525
 526 void block_job_event_completed(BlockJob *job, const char *msg)
 527 {
 528     qapi_event_send_block_job_completed(job->driver->job_type,
 529                                         job->id,
 530                                         job->len,
 531                                         job->offset,
 532                                         job->speed,
 533                                         !!msg,
 534                                         msg,
 535                                         &error_abort);
 536 }
 537
 538 void block_job_event_ready(BlockJob *job)
 539 {
 540     job->ready = true;
 541
 542     qapi_event_send_block_job_ready(job->driver->job_type,
 543                                     job->id,
 544                                     job->len,
 545                                     job->offset,
 546                                     job->speed, &error_abort);
 547 }
 548
 549 BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 550                                         int is_read, int error)
 551 {
 552     BlockErrorAction action;
 553
 554     switch (on_err) {
 555     case BLOCKDEV_ON_ERROR_ENOSPC:
 556     case BLOCKDEV_ON_ERROR_AUTO:
 557         action = (error == ENOSPC) ?
 558                  BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
 559         break;
 560     case BLOCKDEV_ON_ERROR_STOP:
 561         action = BLOCK_ERROR_ACTION_STOP;
 562         break;
 563     case BLOCKDEV_ON_ERROR_REPORT:
 564         action = BLOCK_ERROR_ACTION_REPORT;
 565         break;
 566     case BLOCKDEV_ON_ERROR_IGNORE:
 567         action = BLOCK_ERROR_ACTION_IGNORE;
 568         break;
 569     default:
 570         abort();
 571     }
 572     qapi_event_send_block_job_error(job->id,
 573                                     is_read ? IO_OPERATION_TYPE_READ :
 574                                     IO_OPERATION_TYPE_WRITE,
 575                                     action, &error_abort);
 576     if (action == BLOCK_ERROR_ACTION_STOP) {
 577         /* make the pause user visible, which will be resumed from QMP. */
 578         job->user_paused = true;
 579         block_job_pause(job);
 580         block_job_iostatus_set_err(job, error);
 581     }
 582     return action;
 583 }
 584
 585 typedef struct {
 586     BlockJob *job;
 587     QEMUBH *bh;
 588     AioContext *aio_context;
 589     BlockJobDeferToMainLoopFn *fn;
 590     void *opaque;
 591 } BlockJobDeferToMainLoopData;
 592
 593 static void block_job_defer_to_main_loop_bh(void *opaque)
 594 {
 595     BlockJobDeferToMainLoopData *data = opaque;
 596     AioContext *aio_context;
 597
 598     qemu_bh_delete(data->bh);
 599
 600     /* Prevent race with block_job_defer_to_main_loop() */
 601     aio_context_acquire(data->aio_context);
 602
 603     /* Fetch BDS AioContext again, in case it has changed */
 604     aio_context = blk_get_aio_context(data->job->blk);
 605     aio_context_acquire(aio_context);
 606
 607     data->job->deferred_to_main_loop = false;
 608     data->fn(data->job, data->opaque);
 609
 610     aio_context_release(aio_context);
 611
 612     aio_context_release(data->aio_context);
 613
 614     g_free(data);
 615 }
 616
 617 void block_job_defer_to_main_loop(BlockJob *job,
 618                                   BlockJobDeferToMainLoopFn *fn,
 619                                   void *opaque)
 620 {
 621     BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data));
 622     data->job = job;
 623     data->bh = qemu_bh_new(block_job_defer_to_main_loop_bh, data);
 624     data->aio_context = blk_get_aio_context(job->blk);
 625     data->fn = fn;
 626     data->opaque = opaque;
 627     job->deferred_to_main_loop = true;
 628
 629     qemu_bh_schedule(data->bh);
 630 }
 631
 632 BlockJobTxn *block_job_txn_new(void)
 633 {
 634     BlockJobTxn *txn = g_new0(BlockJobTxn, 1);
 635     QLIST_INIT(&txn->jobs);
 636     txn->refcnt = 1;
 637     return txn;
 638 }
 639
 640 static void block_job_txn_ref(BlockJobTxn *txn)
 641 {
 642     txn->refcnt++;
 643 }
 644
 645 void block_job_txn_unref(BlockJobTxn *txn)
 646 {
 647     if (txn && --txn->refcnt == 0) {
 648         g_free(txn);
 649     }
 650 }
 651
 652 void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job)
 653 {
 654     if (!txn) {
 655         return;
 656     }
 657
 658     assert(!job->txn);
 659     job->txn = txn;
 660
 661     QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
 662     block_job_txn_ref(txn);
 663 }