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 "config-host.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 "qmp-commands.h"
  37 #include "qemu/timer.h"
  38 #include "qapi-event.h"
  39
  40 /* Transactional group of block jobs */
  41 struct BlockJobTxn {
  42
  43     /* Is this txn being cancelled? */
  44     bool aborting;
  45
  46     /* List of jobs */
  47     QLIST_HEAD(, BlockJob) jobs;
  48
  49     /* Reference count */
  50     int refcnt;
  51 };
  52
  53 void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
  54                        int64_t speed, BlockCompletionFunc *cb,
  55                        void *opaque, Error **errp)
  56 {
  57     BlockJob *job;
  58
  59     if (bs->job) {
  60         error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
  61         return NULL;
  62     }
  63     bdrv_ref(bs);
  64     job = g_malloc0(driver->instance_size);
  65     error_setg(&job->blocker, "block device is in use by block job: %s",
  66                BlockJobType_lookup[driver->job_type]);
  67     bdrv_op_block_all(bs, job->blocker);
  68     bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
  69
  70     job->driver        = driver;
  71     job->id            = g_strdup(bdrv_get_device_name(bs));
  72     job->bs            = bs;
  73     job->cb            = cb;
  74     job->opaque        = opaque;
  75     job->busy          = true;
  76     job->refcnt        = 1;
  77     bs->job = job;
  78
  79     /* Only set speed when necessary to avoid NotSupported error */
  80     if (speed != 0) {
  81         Error *local_err = NULL;
  82
  83         block_job_set_speed(job, speed, &local_err);
  84         if (local_err) {
  85             block_job_unref(job);
  86             error_propagate(errp, local_err);
  87             return NULL;
  88         }
  89     }
  90     return job;
  91 }
  92
  93 void block_job_ref(BlockJob *job)
  94 {
  95     ++job->refcnt;
  96 }
  97
  98 void block_job_unref(BlockJob *job)
  99 {
 100     if (--job->refcnt == 0) {
 101         job->bs->job = NULL;
 102         bdrv_op_unblock_all(job->bs, job->blocker);
 103         bdrv_unref(job->bs);
 104         error_free(job->blocker);
 105         g_free(job->id);
 106         g_free(job);
 107     }
 108 }
 109
 110 static void block_job_completed_single(BlockJob *job)
 111 {
 112     if (!job->ret) {
 113         if (job->driver->commit) {
 114             job->driver->commit(job);
 115         }
 116     } else {
 117         if (job->driver->abort) {
 118             job->driver->abort(job);
 119         }
 120     }
 121     job->cb(job->opaque, job->ret);
 122     if (job->txn) {
 123         block_job_txn_unref(job->txn);
 124     }
 125     block_job_unref(job);
 126 }
 127
 128 static void block_job_completed_txn_abort(BlockJob *job)
 129 {
 130     AioContext *ctx;
 131     BlockJobTxn *txn = job->txn;
 132     BlockJob *other_job, *next;
 133
 134     if (txn->aborting) {
 135         /*
 136          * We are cancelled by another job, which will handle everything.
 137          */
 138         return;
 139     }
 140     txn->aborting = true;
 141     /* We are the first failed job. Cancel other jobs. */
 142     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
 143         ctx = bdrv_get_aio_context(other_job->bs);
 144         aio_context_acquire(ctx);
 145     }
 146     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
 147         if (other_job == job || other_job->completed) {
 148             /* Other jobs are "effectively" cancelled by us, set the status for
 149              * them; this job, however, may or may not be cancelled, depending
 150              * on the caller, so leave it. */
 151             if (other_job != job) {
 152                 other_job->cancelled = true;
 153             }
 154             continue;
 155         }
 156         block_job_cancel_sync(other_job);
 157         assert(other_job->completed);
 158     }
 159     QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
 160         ctx = bdrv_get_aio_context(other_job->bs);
 161         block_job_completed_single(other_job);
 162         aio_context_release(ctx);
 163     }
 164 }
 165
 166 static void block_job_completed_txn_success(BlockJob *job)
 167 {
 168     AioContext *ctx;
 169     BlockJobTxn *txn = job->txn;
 170     BlockJob *other_job, *next;
 171     /*
 172      * Successful completion, see if there are other running jobs in this
 173      * txn.
 174      */
 175     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
 176         if (!other_job->completed) {
 177             return;
 178         }
 179     }
 180     /* We are the last completed job, commit the transaction. */
 181     QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
 182         ctx = bdrv_get_aio_context(other_job->bs);
 183         aio_context_acquire(ctx);
 184         assert(other_job->ret == 0);
 185         block_job_completed_single(other_job);
 186         aio_context_release(ctx);
 187     }
 188 }
 189
 190 void block_job_completed(BlockJob *job, int ret)
 191 {
 192     BlockDriverState *bs = job->bs;
 193
 194     assert(bs->job == job);
 195     assert(!job->completed);
 196     job->completed = true;
 197     job->ret = ret;
 198     if (!job->txn) {
 199         block_job_completed_single(job);
 200     } else if (ret < 0 || block_job_is_cancelled(job)) {
 201         block_job_completed_txn_abort(job);
 202     } else {
 203         block_job_completed_txn_success(job);
 204     }
 205 }
 206
 207 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
 208 {
 209     Error *local_err = NULL;
 210
 211     if (!job->driver->set_speed) {
 212         error_setg(errp, QERR_UNSUPPORTED);
 213         return;
 214     }
 215     job->driver->set_speed(job, speed, &local_err);
 216     if (local_err) {
 217         error_propagate(errp, local_err);
 218         return;
 219     }
 220
 221     job->speed = speed;
 222 }
 223
 224 void block_job_complete(BlockJob *job, Error **errp)
 225 {
 226     if (job->pause_count || job->cancelled || !job->driver->complete) {
 227         error_setg(errp, QERR_BLOCK_JOB_NOT_READY, job->id);
 228         return;
 229     }
 230
 231     job->driver->complete(job, errp);
 232 }
 233
 234 void block_job_pause(BlockJob *job)
 235 {
 236     job->pause_count++;
 237 }
 238
 239 bool block_job_is_paused(BlockJob *job)
 240 {
 241     return job->pause_count > 0;
 242 }
 243
 244 void block_job_resume(BlockJob *job)
 245 {
 246     assert(job->pause_count > 0);
 247     job->pause_count--;
 248     if (job->pause_count) {
 249         return;
 250     }
 251     block_job_enter(job);
 252 }
 253
 254 void block_job_enter(BlockJob *job)
 255 {
 256     block_job_iostatus_reset(job);
 257     if (job->co && !job->busy) {
 258         qemu_coroutine_enter(job->co, NULL);
 259     }
 260 }
 261
 262 void block_job_cancel(BlockJob *job)
 263 {
 264     job->cancelled = true;
 265     block_job_enter(job);
 266 }
 267
 268 bool block_job_is_cancelled(BlockJob *job)
 269 {
 270     return job->cancelled;
 271 }
 272
 273 void block_job_iostatus_reset(BlockJob *job)
 274 {
 275     job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
 276     if (job->driver->iostatus_reset) {
 277         job->driver->iostatus_reset(job);
 278     }
 279 }
 280
 281 static int block_job_finish_sync(BlockJob *job,
 282                                  void (*finish)(BlockJob *, Error **errp),
 283                                  Error **errp)
 284 {
 285     BlockDriverState *bs = job->bs;
 286     Error *local_err = NULL;
 287     int ret;
 288
 289     assert(bs->job == job);
 290
 291     block_job_ref(job);
 292     finish(job, &local_err);
 293     if (local_err) {
 294         error_propagate(errp, local_err);
 295         block_job_unref(job);
 296         return -EBUSY;
 297     }
 298     while (!job->completed) {
 299         aio_poll(bdrv_get_aio_context(bs), true);
 300     }
 301     ret = (job->cancelled && job->ret == 0) ? -ECANCELED : job->ret;
 302     block_job_unref(job);
 303     return ret;
 304 }
 305
 306 /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be
 307  * used with block_job_finish_sync() without the need for (rather nasty)
 308  * function pointer casts there. */
 309 static void block_job_cancel_err(BlockJob *job, Error **errp)
 310 {
 311     block_job_cancel(job);
 312 }
 313
 314 int block_job_cancel_sync(BlockJob *job)
 315 {
 316     return block_job_finish_sync(job, &block_job_cancel_err, NULL);
 317 }
 318
 319 int block_job_complete_sync(BlockJob *job, Error **errp)
 320 {
 321     return block_job_finish_sync(job, &block_job_complete, errp);
 322 }
 323
 324 void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
 325 {
 326     assert(job->busy);
 327
 328     /* Check cancellation *before* setting busy = false, too!  */
 329     if (block_job_is_cancelled(job)) {
 330         return;
 331     }
 332
 333     job->busy = false;
 334     if (block_job_is_paused(job)) {
 335         qemu_coroutine_yield();
 336     } else {
 337         co_aio_sleep_ns(bdrv_get_aio_context(job->bs), type, ns);
 338     }
 339     job->busy = true;
 340 }
 341
 342 void block_job_yield(BlockJob *job)
 343 {
 344     assert(job->busy);
 345
 346     /* Check cancellation *before* setting busy = false, too!  */
 347     if (block_job_is_cancelled(job)) {
 348         return;
 349     }
 350
 351     job->busy = false;
 352     qemu_coroutine_yield();
 353     job->busy = true;
 354 }
 355
 356 BlockJobInfo *block_job_query(BlockJob *job)
 357 {
 358     BlockJobInfo *info = g_new0(BlockJobInfo, 1);
 359     info->type      = g_strdup(BlockJobType_lookup[job->driver->job_type]);
 360     info->device    = g_strdup(job->id);
 361     info->len       = job->len;
 362     info->busy      = job->busy;
 363     info->paused    = job->pause_count > 0;
 364     info->offset    = job->offset;
 365     info->speed     = job->speed;
 366     info->io_status = job->iostatus;
 367     info->ready     = job->ready;
 368     return info;
 369 }
 370
 371 static void block_job_iostatus_set_err(BlockJob *job, int error)
 372 {
 373     if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
 374         job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
 375                                           BLOCK_DEVICE_IO_STATUS_FAILED;
 376     }
 377 }
 378
 379 void block_job_event_cancelled(BlockJob *job)
 380 {
 381     qapi_event_send_block_job_cancelled(job->driver->job_type,
 382                                         job->id,
 383                                         job->len,
 384                                         job->offset,
 385                                         job->speed,
 386                                         &error_abort);
 387 }
 388
 389 void block_job_event_completed(BlockJob *job, const char *msg)
 390 {
 391     qapi_event_send_block_job_completed(job->driver->job_type,
 392                                         job->id,
 393                                         job->len,
 394                                         job->offset,
 395                                         job->speed,
 396                                         !!msg,
 397                                         msg,
 398                                         &error_abort);
 399 }
 400
 401 void block_job_event_ready(BlockJob *job)
 402 {
 403     job->ready = true;
 404
 405     qapi_event_send_block_job_ready(job->driver->job_type,
 406                                     job->id,
 407                                     job->len,
 408                                     job->offset,
 409                                     job->speed, &error_abort);
 410 }
 411
 412 BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
 413                                         BlockdevOnError on_err,
 414                                         int is_read, int error)
 415 {
 416     BlockErrorAction action;
 417
 418     switch (on_err) {
 419     case BLOCKDEV_ON_ERROR_ENOSPC:
 420         action = (error == ENOSPC) ?
 421                  BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
 422         break;
 423     case BLOCKDEV_ON_ERROR_STOP:
 424         action = BLOCK_ERROR_ACTION_STOP;
 425         break;
 426     case BLOCKDEV_ON_ERROR_REPORT:
 427         action = BLOCK_ERROR_ACTION_REPORT;
 428         break;
 429     case BLOCKDEV_ON_ERROR_IGNORE:
 430         action = BLOCK_ERROR_ACTION_IGNORE;
 431         break;
 432     default:
 433         abort();
 434     }
 435     qapi_event_send_block_job_error(job->id,
 436                                     is_read ? IO_OPERATION_TYPE_READ :
 437                                     IO_OPERATION_TYPE_WRITE,
 438                                     action, &error_abort);
 439     if (action == BLOCK_ERROR_ACTION_STOP) {
 440         /* make the pause user visible, which will be resumed from QMP. */
 441         job->user_paused = true;
 442         block_job_pause(job);
 443         block_job_iostatus_set_err(job, error);
 444         if (bs->blk && bs != job->bs) {
 445             blk_iostatus_set_err(bs->blk, error);
 446         }
 447     }
 448     return action;
 449 }
 450
 451 typedef struct {
 452     BlockJob *job;
 453     QEMUBH *bh;
 454     AioContext *aio_context;
 455     BlockJobDeferToMainLoopFn *fn;
 456     void *opaque;
 457 } BlockJobDeferToMainLoopData;
 458
 459 static void block_job_defer_to_main_loop_bh(void *opaque)
 460 {
 461     BlockJobDeferToMainLoopData *data = opaque;
 462     AioContext *aio_context;
 463
 464     qemu_bh_delete(data->bh);
 465
 466     /* Prevent race with block_job_defer_to_main_loop() */
 467     aio_context_acquire(data->aio_context);
 468
 469     /* Fetch BDS AioContext again, in case it has changed */
 470     aio_context = bdrv_get_aio_context(data->job->bs);
 471     aio_context_acquire(aio_context);
 472
 473     data->fn(data->job, data->opaque);
 474
 475     aio_context_release(aio_context);
 476
 477     aio_context_release(data->aio_context);
 478
 479     g_free(data);
 480 }
 481
 482 void block_job_defer_to_main_loop(BlockJob *job,
 483                                   BlockJobDeferToMainLoopFn *fn,
 484                                   void *opaque)
 485 {
 486     BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data));
 487     data->job = job;
 488     data->bh = qemu_bh_new(block_job_defer_to_main_loop_bh, data);
 489     data->aio_context = bdrv_get_aio_context(job->bs);
 490     data->fn = fn;
 491     data->opaque = opaque;
 492
 493     qemu_bh_schedule(data->bh);
 494 }
 495
 496 BlockJobTxn *block_job_txn_new(void)
 497 {
 498     BlockJobTxn *txn = g_new0(BlockJobTxn, 1);
 499     QLIST_INIT(&txn->jobs);
 500     txn->refcnt = 1;
 501     return txn;
 502 }
 503
 504 static void block_job_txn_ref(BlockJobTxn *txn)
 505 {
 506     txn->refcnt++;
 507 }
 508
 509 void block_job_txn_unref(BlockJobTxn *txn)
 510 {
 511     if (txn && --txn->refcnt == 0) {
 512         g_free(txn);
 513     }
 514 }
 515
 516 void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job)
 517 {
 518     if (!txn) {
 519         return;
 520     }
 521
 522     assert(!job->txn);
 523     job->txn = txn;
 524
 525     QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
 526     block_job_txn_ref(txn);
 527 }