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