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 "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(job->deferred_to_main_loop ? qemu_get_aio_context() :
 300                                               bdrv_get_aio_context(bs),
 301                  true);
 302     }
 303     ret = (job->cancelled && job->ret == 0) ? -ECANCELED : job->ret;
 304     block_job_unref(job);
 305     return ret;
 306 }
 307
 308 /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be
 309  * used with block_job_finish_sync() without the need for (rather nasty)
 310  * function pointer casts there. */
 311 static void block_job_cancel_err(BlockJob *job, Error **errp)
 312 {
 313     block_job_cancel(job);
 314 }
 315
 316 int block_job_cancel_sync(BlockJob *job)
 317 {
 318     return block_job_finish_sync(job, &block_job_cancel_err, NULL);
 319 }
 320
 321 int block_job_complete_sync(BlockJob *job, Error **errp)
 322 {
 323     return block_job_finish_sync(job, &block_job_complete, errp);
 324 }
 325
 326 void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
 327 {
 328     assert(job->busy);
 329
 330     /* Check cancellation *before* setting busy = false, too!  */
 331     if (block_job_is_cancelled(job)) {
 332         return;
 333     }
 334
 335     job->busy = false;
 336     if (block_job_is_paused(job)) {
 337         qemu_coroutine_yield();
 338     } else {
 339         co_aio_sleep_ns(bdrv_get_aio_context(job->bs), type, ns);
 340     }
 341     job->busy = true;
 342 }
 343
 344 void block_job_yield(BlockJob *job)
 345 {
 346     assert(job->busy);
 347
 348     /* Check cancellation *before* setting busy = false, too!  */
 349     if (block_job_is_cancelled(job)) {
 350         return;
 351     }
 352
 353     job->busy = false;
 354     qemu_coroutine_yield();
 355     job->busy = true;
 356 }
 357
 358 BlockJobInfo *block_job_query(BlockJob *job)
 359 {
 360     BlockJobInfo *info = g_new0(BlockJobInfo, 1);
 361     info->type      = g_strdup(BlockJobType_lookup[job->driver->job_type]);
 362     info->device    = g_strdup(job->id);
 363     info->len       = job->len;
 364     info->busy      = job->busy;
 365     info->paused    = job->pause_count > 0;
 366     info->offset    = job->offset;
 367     info->speed     = job->speed;
 368     info->io_status = job->iostatus;
 369     info->ready     = job->ready;
 370     return info;
 371 }
 372
 373 static void block_job_iostatus_set_err(BlockJob *job, int error)
 374 {
 375     if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
 376         job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
 377                                           BLOCK_DEVICE_IO_STATUS_FAILED;
 378     }
 379 }
 380
 381 void block_job_event_cancelled(BlockJob *job)
 382 {
 383     qapi_event_send_block_job_cancelled(job->driver->job_type,
 384                                         job->id,
 385                                         job->len,
 386                                         job->offset,
 387                                         job->speed,
 388                                         &error_abort);
 389 }
 390
 391 void block_job_event_completed(BlockJob *job, const char *msg)
 392 {
 393     qapi_event_send_block_job_completed(job->driver->job_type,
 394                                         job->id,
 395                                         job->len,
 396                                         job->offset,
 397                                         job->speed,
 398                                         !!msg,
 399                                         msg,
 400                                         &error_abort);
 401 }
 402
 403 void block_job_event_ready(BlockJob *job)
 404 {
 405     job->ready = true;
 406
 407     qapi_event_send_block_job_ready(job->driver->job_type,
 408                                     job->id,
 409                                     job->len,
 410                                     job->offset,
 411                                     job->speed, &error_abort);
 412 }
 413
 414 BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 415                                         int is_read, int error)
 416 {
 417     BlockErrorAction action;
 418
 419     switch (on_err) {
 420     case BLOCKDEV_ON_ERROR_ENOSPC:
 421         action = (error == ENOSPC) ?
 422                  BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
 423         break;
 424     case BLOCKDEV_ON_ERROR_STOP:
 425         action = BLOCK_ERROR_ACTION_STOP;
 426         break;
 427     case BLOCKDEV_ON_ERROR_REPORT:
 428         action = BLOCK_ERROR_ACTION_REPORT;
 429         break;
 430     case BLOCKDEV_ON_ERROR_IGNORE:
 431         action = BLOCK_ERROR_ACTION_IGNORE;
 432         break;
 433     default:
 434         abort();
 435     }
 436     qapi_event_send_block_job_error(job->id,
 437                                     is_read ? IO_OPERATION_TYPE_READ :
 438                                     IO_OPERATION_TYPE_WRITE,
 439                                     action, &error_abort);
 440     if (action == BLOCK_ERROR_ACTION_STOP) {
 441         /* make the pause user visible, which will be resumed from QMP. */
 442         job->user_paused = true;
 443         block_job_pause(job);
 444         block_job_iostatus_set_err(job, error);
 445     }
 446     return action;
 447 }
 448
 449 typedef struct {
 450     BlockJob *job;
 451     QEMUBH *bh;
 452     AioContext *aio_context;
 453     BlockJobDeferToMainLoopFn *fn;
 454     void *opaque;
 455 } BlockJobDeferToMainLoopData;
 456
 457 static void block_job_defer_to_main_loop_bh(void *opaque)
 458 {
 459     BlockJobDeferToMainLoopData *data = opaque;
 460     AioContext *aio_context;
 461
 462     qemu_bh_delete(data->bh);
 463
 464     /* Prevent race with block_job_defer_to_main_loop() */
 465     aio_context_acquire(data->aio_context);
 466
 467     /* Fetch BDS AioContext again, in case it has changed */
 468     aio_context = bdrv_get_aio_context(data->job->bs);
 469     aio_context_acquire(aio_context);
 470
 471     data->job->deferred_to_main_loop = false;
 472     data->fn(data->job, data->opaque);
 473
 474     aio_context_release(aio_context);
 475
 476     aio_context_release(data->aio_context);
 477
 478     g_free(data);
 479 }
 480
 481 void block_job_defer_to_main_loop(BlockJob *job,
 482                                   BlockJobDeferToMainLoopFn *fn,
 483                                   void *opaque)
 484 {
 485     BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data));
 486     data->job = job;
 487     data->bh = qemu_bh_new(block_job_defer_to_main_loop_bh, data);
 488     data->aio_context = bdrv_get_aio_context(job->bs);
 489     data->fn = fn;
 490     data->opaque = opaque;
 491     job->deferred_to_main_loop = true;
 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 }