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 "block/block.h"
  28 #include "block/blockjob_int.h"
  29 #include "block/block_int.h"
  30 #include "block/trace.h"
  31 #include "sysemu/block-backend.h"
  32 #include "qapi/error.h"
  33 #include "qapi/qapi-events-block-core.h"
  34 #include "qapi/qmp/qerror.h"
  35 #include "qemu/coroutine.h"
  36 #include "qemu/main-loop.h"
  37 #include "qemu/timer.h"
  38
  39 /*
  40  * The block job API is composed of two categories of functions.
  41  *
  42  * The first includes functions used by the monitor.  The monitor is
  43  * peculiar in that it accesses the block job list with block_job_get, and
  44  * therefore needs consistency across block_job_get and the actual operation
  45  * (e.g. block_job_set_speed).  The consistency is achieved with
  46  * aio_context_acquire/release.  These functions are declared in blockjob.h.
  47  *
  48  * The second includes functions used by the block job drivers and sometimes
  49  * by the core block layer.  These do not care about locking, because the
  50  * whole coroutine runs under the AioContext lock, and are declared in
  51  * blockjob_int.h.
  52  */
  53
  54 static bool is_block_job(Job *job)
  55 {
  56     return job_type(job) == JOB_TYPE_BACKUP ||
  57            job_type(job) == JOB_TYPE_COMMIT ||
  58            job_type(job) == JOB_TYPE_MIRROR ||
  59            job_type(job) == JOB_TYPE_STREAM;
  60 }
  61
  62 BlockJob *block_job_next(BlockJob *bjob)
  63 {
  64     Job *job = bjob ? &bjob->job : NULL;
  65     GLOBAL_STATE_CODE();
  66
  67     do {
  68         job = job_next(job);
  69     } while (job && !is_block_job(job));
  70
  71     return job ? container_of(job, BlockJob, job) : NULL;
  72 }
  73
  74 BlockJob *block_job_get(const char *id)
  75 {
  76     Job *job = job_get(id);
  77     GLOBAL_STATE_CODE();
  78
  79     if (job && is_block_job(job)) {
  80         return container_of(job, BlockJob, job);
  81     } else {
  82         return NULL;
  83     }
  84 }
  85
  86 void block_job_free(Job *job)
  87 {
  88     BlockJob *bjob = container_of(job, BlockJob, job);
  89     GLOBAL_STATE_CODE();
  90
  91     block_job_remove_all_bdrv(bjob);
  92     ratelimit_destroy(&bjob->limit);
  93     error_free(bjob->blocker);
  94 }
  95
  96 static char *child_job_get_parent_desc(BdrvChild *c)
  97 {
  98     BlockJob *job = c->opaque;
  99     return g_strdup_printf("%s job '%s'", job_type_str(&job->job), job->job.id);
 100 }
 101
 102 static void child_job_drained_begin(BdrvChild *c)
 103 {
 104     BlockJob *job = c->opaque;
 105     job_pause(&job->job);
 106 }
 107
 108 static bool child_job_drained_poll(BdrvChild *c)
 109 {
 110     BlockJob *bjob = c->opaque;
 111     Job *job = &bjob->job;
 112     const BlockJobDriver *drv = block_job_driver(bjob);
 113
 114     /* An inactive or completed job doesn't have any pending requests. Jobs
 115      * with !job->busy are either already paused or have a pause point after
 116      * being reentered, so no job driver code will run before they pause. */
 117     if (!job->busy || job_is_completed(job)) {
 118         return false;
 119     }
 120
 121     /* Otherwise, assume that it isn't fully stopped yet, but allow the job to
 122      * override this assumption. */
 123     if (drv->drained_poll) {
 124         return drv->drained_poll(bjob);
 125     } else {
 126         return true;
 127     }
 128 }
 129
 130 static void child_job_drained_end(BdrvChild *c, int *drained_end_counter)
 131 {
 132     BlockJob *job = c->opaque;
 133     job_resume(&job->job);
 134 }
 135
 136 static bool child_job_can_set_aio_ctx(BdrvChild *c, AioContext *ctx,
 137                                       GSList **ignore, Error **errp)
 138 {
 139     BlockJob *job = c->opaque;
 140     GSList *l;
 141
 142     for (l = job->nodes; l; l = l->next) {
 143         BdrvChild *sibling = l->data;
 144         if (!bdrv_child_can_set_aio_context(sibling, ctx, ignore, errp)) {
 145             return false;
 146         }
 147     }
 148     return true;
 149 }
 150
 151 static void child_job_set_aio_ctx(BdrvChild *c, AioContext *ctx,
 152                                   GSList **ignore)
 153 {
 154     BlockJob *job = c->opaque;
 155     GSList *l;
 156
 157     for (l = job->nodes; l; l = l->next) {
 158         BdrvChild *sibling = l->data;
 159         if (g_slist_find(*ignore, sibling)) {
 160             continue;
 161         }
 162         *ignore = g_slist_prepend(*ignore, sibling);
 163         bdrv_set_aio_context_ignore(sibling->bs, ctx, ignore);
 164     }
 165
 166     job->job.aio_context = ctx;
 167 }
 168
 169 static AioContext *child_job_get_parent_aio_context(BdrvChild *c)
 170 {
 171     BlockJob *job = c->opaque;
 172
 173     return job->job.aio_context;
 174 }
 175
 176 static const BdrvChildClass child_job = {
 177     .get_parent_desc    = child_job_get_parent_desc,
 178     .drained_begin      = child_job_drained_begin,
 179     .drained_poll       = child_job_drained_poll,
 180     .drained_end        = child_job_drained_end,
 181     .can_set_aio_ctx    = child_job_can_set_aio_ctx,
 182     .set_aio_ctx        = child_job_set_aio_ctx,
 183     .stay_at_node       = true,
 184     .get_parent_aio_context = child_job_get_parent_aio_context,
 185 };
 186
 187 void block_job_remove_all_bdrv(BlockJob *job)
 188 {
 189     GLOBAL_STATE_CODE();
 190     /*
 191      * bdrv_root_unref_child() may reach child_job_[can_]set_aio_ctx(),
 192      * which will also traverse job->nodes, so consume the list one by
 193      * one to make sure that such a concurrent access does not attempt
 194      * to process an already freed BdrvChild.
 195      */
 196     while (job->nodes) {
 197         GSList *l = job->nodes;
 198         BdrvChild *c = l->data;
 199
 200         job->nodes = l->next;
 201
 202         bdrv_op_unblock_all(c->bs, job->blocker);
 203         bdrv_root_unref_child(c);
 204
 205         g_slist_free_1(l);
 206     }
 207 }
 208
 209 bool block_job_has_bdrv(BlockJob *job, BlockDriverState *bs)
 210 {
 211     GSList *el;
 212     GLOBAL_STATE_CODE();
 213
 214     for (el = job->nodes; el; el = el->next) {
 215         BdrvChild *c = el->data;
 216         if (c->bs == bs) {
 217             return true;
 218         }
 219     }
 220
 221     return false;
 222 }
 223
 224 int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
 225                        uint64_t perm, uint64_t shared_perm, Error **errp)
 226 {
 227     BdrvChild *c;
 228     bool need_context_ops;
 229     GLOBAL_STATE_CODE();
 230
 231     bdrv_ref(bs);
 232
 233     need_context_ops = bdrv_get_aio_context(bs) != job->job.aio_context;
 234
 235     if (need_context_ops && job->job.aio_context != qemu_get_aio_context()) {
 236         aio_context_release(job->job.aio_context);
 237     }
 238     c = bdrv_root_attach_child(bs, name, &child_job, 0, perm, shared_perm, job,
 239                                errp);
 240     if (need_context_ops && job->job.aio_context != qemu_get_aio_context()) {
 241         aio_context_acquire(job->job.aio_context);
 242     }
 243     if (c == NULL) {
 244         return -EPERM;
 245     }
 246
 247     job->nodes = g_slist_prepend(job->nodes, c);
 248     bdrv_op_block_all(bs, job->blocker);
 249
 250     return 0;
 251 }
 252
 253 static void block_job_on_idle(Notifier *n, void *opaque)
 254 {
 255     aio_wait_kick();
 256 }
 257
 258 bool block_job_is_internal(BlockJob *job)
 259 {
 260     return (job->job.id == NULL);
 261 }
 262
 263 const BlockJobDriver *block_job_driver(BlockJob *job)
 264 {
 265     return container_of(job->job.driver, BlockJobDriver, job_driver);
 266 }
 267
 268 /* Assumes the job_mutex is held */
 269 static bool job_timer_pending(Job *job)
 270 {
 271     return timer_pending(&job->sleep_timer);
 272 }
 273
 274 bool block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
 275 {
 276     const BlockJobDriver *drv = block_job_driver(job);
 277     int64_t old_speed = job->speed;
 278
 279     GLOBAL_STATE_CODE();
 280
 281     if (job_apply_verb(&job->job, JOB_VERB_SET_SPEED, errp) < 0) {
 282         return false;
 283     }
 284     if (speed < 0) {
 285         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "speed",
 286                    "a non-negative value");
 287         return false;
 288     }
 289
 290     ratelimit_set_speed(&job->limit, speed, BLOCK_JOB_SLICE_TIME);
 291
 292     job->speed = speed;
 293
 294     if (drv->set_speed) {
 295         drv->set_speed(job, speed);
 296     }
 297
 298     if (speed && speed <= old_speed) {
 299         return true;
 300     }
 301
 302     /* kick only if a timer is pending */
 303     job_enter_cond(&job->job, job_timer_pending);
 304
 305     return true;
 306 }
 307
 308 int64_t block_job_ratelimit_get_delay(BlockJob *job, uint64_t n)
 309 {
 310     IO_CODE();
 311     return ratelimit_calculate_delay(&job->limit, n);
 312 }
 313
 314 BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
 315 {
 316     BlockJobInfo *info;
 317     uint64_t progress_current, progress_total;
 318
 319     GLOBAL_STATE_CODE();
 320
 321     if (block_job_is_internal(job)) {
 322         error_setg(errp, "Cannot query QEMU internal jobs");
 323         return NULL;
 324     }
 325
 326     progress_get_snapshot(&job->job.progress, &progress_current,
 327                           &progress_total);
 328
 329     info = g_new0(BlockJobInfo, 1);
 330     info->type      = g_strdup(job_type_str(&job->job));
 331     info->device    = g_strdup(job->job.id);
 332     info->busy      = qatomic_read(&job->job.busy);
 333     info->paused    = job->job.pause_count > 0;
 334     info->offset    = progress_current;
 335     info->len       = progress_total;
 336     info->speed     = job->speed;
 337     info->io_status = job->iostatus;
 338     info->ready     = job_is_ready(&job->job),
 339     info->status    = job->job.status;
 340     info->auto_finalize = job->job.auto_finalize;
 341     info->auto_dismiss  = job->job.auto_dismiss;
 342     if (job->job.ret) {
 343         info->has_error = true;
 344         info->error = job->job.err ?
 345                         g_strdup(error_get_pretty(job->job.err)) :
 346                         g_strdup(strerror(-job->job.ret));
 347     }
 348     return info;
 349 }
 350
 351 static void block_job_iostatus_set_err(BlockJob *job, int error)
 352 {
 353     if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
 354         job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
 355                                           BLOCK_DEVICE_IO_STATUS_FAILED;
 356     }
 357 }
 358
 359 static void block_job_event_cancelled(Notifier *n, void *opaque)
 360 {
 361     BlockJob *job = opaque;
 362     uint64_t progress_current, progress_total;
 363
 364     if (block_job_is_internal(job)) {
 365         return;
 366     }
 367
 368     progress_get_snapshot(&job->job.progress, &progress_current,
 369                           &progress_total);
 370
 371     qapi_event_send_block_job_cancelled(job_type(&job->job),
 372                                         job->job.id,
 373                                         progress_total,
 374                                         progress_current,
 375                                         job->speed);
 376 }
 377
 378 static void block_job_event_completed(Notifier *n, void *opaque)
 379 {
 380     BlockJob *job = opaque;
 381     const char *msg = NULL;
 382     uint64_t progress_current, progress_total;
 383
 384     if (block_job_is_internal(job)) {
 385         return;
 386     }
 387
 388     if (job->job.ret < 0) {
 389         msg = error_get_pretty(job->job.err);
 390     }
 391
 392     progress_get_snapshot(&job->job.progress, &progress_current,
 393                           &progress_total);
 394
 395     qapi_event_send_block_job_completed(job_type(&job->job),
 396                                         job->job.id,
 397                                         progress_total,
 398                                         progress_current,
 399                                         job->speed,
 400                                         !!msg,
 401                                         msg);
 402 }
 403
 404 static void block_job_event_pending(Notifier *n, void *opaque)
 405 {
 406     BlockJob *job = opaque;
 407
 408     if (block_job_is_internal(job)) {
 409         return;
 410     }
 411
 412     qapi_event_send_block_job_pending(job_type(&job->job),
 413                                       job->job.id);
 414 }
 415
 416 static void block_job_event_ready(Notifier *n, void *opaque)
 417 {
 418     BlockJob *job = opaque;
 419     uint64_t progress_current, progress_total;
 420
 421     if (block_job_is_internal(job)) {
 422         return;
 423     }
 424
 425     progress_get_snapshot(&job->job.progress, &progress_current,
 426                           &progress_total);
 427
 428     qapi_event_send_block_job_ready(job_type(&job->job),
 429                                     job->job.id,
 430                                     progress_total,
 431                                     progress_current,
 432                                     job->speed);
 433 }
 434
 435
 436 /*
 437  * API for block job drivers and the block layer.  These functions are
 438  * declared in blockjob_int.h.
 439  */
 440
 441 void *block_job_create(const char *job_id, const BlockJobDriver *driver,
 442                        JobTxn *txn, BlockDriverState *bs, uint64_t perm,
 443                        uint64_t shared_perm, int64_t speed, int flags,
 444                        BlockCompletionFunc *cb, void *opaque, Error **errp)
 445 {
 446     BlockJob *job;
 447     int ret;
 448     GLOBAL_STATE_CODE();
 449
 450     if (job_id == NULL && !(flags & JOB_INTERNAL)) {
 451         job_id = bdrv_get_device_name(bs);
 452     }
 453
 454     job = job_create(job_id, &driver->job_driver, txn, bdrv_get_aio_context(bs),
 455                      flags, cb, opaque, errp);
 456     if (job == NULL) {
 457         return NULL;
 458     }
 459
 460     assert(is_block_job(&job->job));
 461     assert(job->job.driver->free == &block_job_free);
 462     assert(job->job.driver->user_resume == &block_job_user_resume);
 463
 464     ratelimit_init(&job->limit);
 465
 466     job->finalize_cancelled_notifier.notify = block_job_event_cancelled;
 467     job->finalize_completed_notifier.notify = block_job_event_completed;
 468     job->pending_notifier.notify = block_job_event_pending;
 469     job->ready_notifier.notify = block_job_event_ready;
 470     job->idle_notifier.notify = block_job_on_idle;
 471
 472     notifier_list_add(&job->job.on_finalize_cancelled,
 473                       &job->finalize_cancelled_notifier);
 474     notifier_list_add(&job->job.on_finalize_completed,
 475                       &job->finalize_completed_notifier);
 476     notifier_list_add(&job->job.on_pending, &job->pending_notifier);
 477     notifier_list_add(&job->job.on_ready, &job->ready_notifier);
 478     notifier_list_add(&job->job.on_idle, &job->idle_notifier);
 479
 480     error_setg(&job->blocker, "block device is in use by block job: %s",
 481                job_type_str(&job->job));
 482
 483     ret = block_job_add_bdrv(job, "main node", bs, perm, shared_perm, errp);
 484     if (ret < 0) {
 485         goto fail;
 486     }
 487
 488     bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
 489
 490     if (!block_job_set_speed(job, speed, errp)) {
 491         goto fail;
 492     }
 493
 494     return job;
 495
 496 fail:
 497     job_early_fail(&job->job);
 498     return NULL;
 499 }
 500
 501 void block_job_iostatus_reset(BlockJob *job)
 502 {
 503     GLOBAL_STATE_CODE();
 504     if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
 505         return;
 506     }
 507     assert(job->job.user_paused && job->job.pause_count > 0);
 508     job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
 509 }
 510
 511 void block_job_user_resume(Job *job)
 512 {
 513     BlockJob *bjob = container_of(job, BlockJob, job);
 514     GLOBAL_STATE_CODE();
 515     block_job_iostatus_reset(bjob);
 516 }
 517
 518 BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 519                                         int is_read, int error)
 520 {
 521     BlockErrorAction action;
 522     IO_CODE();
 523
 524     switch (on_err) {
 525     case BLOCKDEV_ON_ERROR_ENOSPC:
 526     case BLOCKDEV_ON_ERROR_AUTO:
 527         action = (error == ENOSPC) ?
 528                  BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
 529         break;
 530     case BLOCKDEV_ON_ERROR_STOP:
 531         action = BLOCK_ERROR_ACTION_STOP;
 532         break;
 533     case BLOCKDEV_ON_ERROR_REPORT:
 534         action = BLOCK_ERROR_ACTION_REPORT;
 535         break;
 536     case BLOCKDEV_ON_ERROR_IGNORE:
 537         action = BLOCK_ERROR_ACTION_IGNORE;
 538         break;
 539     default:
 540         abort();
 541     }
 542     if (!block_job_is_internal(job)) {
 543         qapi_event_send_block_job_error(job->job.id,
 544                                         is_read ? IO_OPERATION_TYPE_READ :
 545                                         IO_OPERATION_TYPE_WRITE,
 546                                         action);
 547     }
 548     if (action == BLOCK_ERROR_ACTION_STOP) {
 549         if (!job->job.user_paused) {
 550             job_pause(&job->job);
 551             /* make the pause user visible, which will be resumed from QMP. */
 552             job->job.user_paused = true;
 553         }
 554         block_job_iostatus_set_err(job, error);
 555     }
 556     return action;
 557 }
 558
 559 AioContext *block_job_get_aio_context(BlockJob *job)
 560 {
 561     GLOBAL_STATE_CODE();
 562     return job->job.aio_context;
 563 }