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 "qapi/qmp/qerror.h"
  33 #include "qapi/qmp/qjson.h"
  34 #include "block/coroutine.h"
  35 #include "qmp-commands.h"
  36 #include "qemu/timer.h"
  37 #include "qapi-event.h"
  38
  39 void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
  40                        int64_t speed, BlockCompletionFunc *cb,
  41                        void *opaque, Error **errp)
  42 {
  43     BlockJob *job;
  44
  45     if (bs->job) {
  46         error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
  47         return NULL;
  48     }
  49     bdrv_ref(bs);
  50     job = g_malloc0(driver->instance_size);
  51     error_setg(&job->blocker, "block device is in use by block job: %s",
  52                BlockJobType_lookup[driver->job_type]);
  53     bdrv_op_block_all(bs, job->blocker);
  54     bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
  55
  56     job->driver        = driver;
  57     job->id            = g_strdup(bdrv_get_device_name(bs));
  58     job->bs            = bs;
  59     job->cb            = cb;
  60     job->opaque        = opaque;
  61     job->busy          = true;
  62     bs->job = job;
  63
  64     /* Only set speed when necessary to avoid NotSupported error */
  65     if (speed != 0) {
  66         Error *local_err = NULL;
  67
  68         block_job_set_speed(job, speed, &local_err);
  69         if (local_err) {
  70             block_job_release(bs);
  71             error_propagate(errp, local_err);
  72             return NULL;
  73         }
  74     }
  75     return job;
  76 }
  77
  78 void block_job_release(BlockDriverState *bs)
  79 {
  80     BlockJob *job = bs->job;
  81
  82     bs->job = NULL;
  83     bdrv_op_unblock_all(bs, job->blocker);
  84     error_free(job->blocker);
  85     g_free(job->id);
  86     g_free(job);
  87 }
  88
  89 void block_job_completed(BlockJob *job, int ret)
  90 {
  91     BlockDriverState *bs = job->bs;
  92
  93     assert(bs->job == job);
  94     job->cb(job->opaque, ret);
  95     block_job_release(bs);
  96 }
  97
  98 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
  99 {
 100     Error *local_err = NULL;
 101
 102     if (!job->driver->set_speed) {
 103         error_setg(errp, QERR_UNSUPPORTED);
 104         return;
 105     }
 106     job->driver->set_speed(job, speed, &local_err);
 107     if (local_err) {
 108         error_propagate(errp, local_err);
 109         return;
 110     }
 111
 112     job->speed = speed;
 113 }
 114
 115 void block_job_complete(BlockJob *job, Error **errp)
 116 {
 117     if (job->pause_count || job->cancelled || !job->driver->complete) {
 118         error_setg(errp, QERR_BLOCK_JOB_NOT_READY, job->id);
 119         return;
 120     }
 121
 122     job->driver->complete(job, errp);
 123 }
 124
 125 void block_job_pause(BlockJob *job)
 126 {
 127     job->pause_count++;
 128 }
 129
 130 bool block_job_is_paused(BlockJob *job)
 131 {
 132     return job->pause_count > 0;
 133 }
 134
 135 void block_job_resume(BlockJob *job)
 136 {
 137     assert(job->pause_count > 0);
 138     job->pause_count--;
 139     if (job->pause_count) {
 140         return;
 141     }
 142     block_job_enter(job);
 143 }
 144
 145 void block_job_enter(BlockJob *job)
 146 {
 147     block_job_iostatus_reset(job);
 148     if (job->co && !job->busy) {
 149         qemu_coroutine_enter(job->co, NULL);
 150     }
 151 }
 152
 153 void block_job_cancel(BlockJob *job)
 154 {
 155     job->cancelled = true;
 156     block_job_enter(job);
 157 }
 158
 159 bool block_job_is_cancelled(BlockJob *job)
 160 {
 161     return job->cancelled;
 162 }
 163
 164 void block_job_iostatus_reset(BlockJob *job)
 165 {
 166     job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
 167     if (job->driver->iostatus_reset) {
 168         job->driver->iostatus_reset(job);
 169     }
 170 }
 171
 172 struct BlockFinishData {
 173     BlockJob *job;
 174     BlockCompletionFunc *cb;
 175     void *opaque;
 176     bool cancelled;
 177     int ret;
 178 };
 179
 180 static void block_job_finish_cb(void *opaque, int ret)
 181 {
 182     struct BlockFinishData *data = opaque;
 183
 184     data->cancelled = block_job_is_cancelled(data->job);
 185     data->ret = ret;
 186     data->cb(data->opaque, ret);
 187 }
 188
 189 static int block_job_finish_sync(BlockJob *job,
 190                                  void (*finish)(BlockJob *, Error **errp),
 191                                  Error **errp)
 192 {
 193     struct BlockFinishData data;
 194     BlockDriverState *bs = job->bs;
 195     Error *local_err = NULL;
 196
 197     assert(bs->job == job);
 198
 199     /* Set up our own callback to store the result and chain to
 200      * the original callback.
 201      */
 202     data.job = job;
 203     data.cb = job->cb;
 204     data.opaque = job->opaque;
 205     data.ret = -EINPROGRESS;
 206     job->cb = block_job_finish_cb;
 207     job->opaque = &data;
 208     finish(job, &local_err);
 209     if (local_err) {
 210         error_propagate(errp, local_err);
 211         return -EBUSY;
 212     }
 213     while (data.ret == -EINPROGRESS) {
 214         aio_poll(bdrv_get_aio_context(bs), true);
 215     }
 216     return (data.cancelled && data.ret == 0) ? -ECANCELED : data.ret;
 217 }
 218
 219 /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be
 220  * used with block_job_finish_sync() without the need for (rather nasty)
 221  * function pointer casts there. */
 222 static void block_job_cancel_err(BlockJob *job, Error **errp)
 223 {
 224     block_job_cancel(job);
 225 }
 226
 227 int block_job_cancel_sync(BlockJob *job)
 228 {
 229     return block_job_finish_sync(job, &block_job_cancel_err, NULL);
 230 }
 231
 232 int block_job_complete_sync(BlockJob *job, Error **errp)
 233 {
 234     return block_job_finish_sync(job, &block_job_complete, errp);
 235 }
 236
 237 void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
 238 {
 239     assert(job->busy);
 240
 241     /* Check cancellation *before* setting busy = false, too!  */
 242     if (block_job_is_cancelled(job)) {
 243         return;
 244     }
 245
 246     job->busy = false;
 247     if (block_job_is_paused(job)) {
 248         qemu_coroutine_yield();
 249     } else {
 250         co_aio_sleep_ns(bdrv_get_aio_context(job->bs), type, ns);
 251     }
 252     job->busy = true;
 253 }
 254
 255 void block_job_yield(BlockJob *job)
 256 {
 257     assert(job->busy);
 258
 259     /* Check cancellation *before* setting busy = false, too!  */
 260     if (block_job_is_cancelled(job)) {
 261         return;
 262     }
 263
 264     job->busy = false;
 265     qemu_coroutine_yield();
 266     job->busy = true;
 267 }
 268
 269 BlockJobInfo *block_job_query(BlockJob *job)
 270 {
 271     BlockJobInfo *info = g_new0(BlockJobInfo, 1);
 272     info->type      = g_strdup(BlockJobType_lookup[job->driver->job_type]);
 273     info->device    = g_strdup(job->id);
 274     info->len       = job->len;
 275     info->busy      = job->busy;
 276     info->paused    = job->pause_count > 0;
 277     info->offset    = job->offset;
 278     info->speed     = job->speed;
 279     info->io_status = job->iostatus;
 280     info->ready     = job->ready;
 281     return info;
 282 }
 283
 284 static void block_job_iostatus_set_err(BlockJob *job, int error)
 285 {
 286     if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
 287         job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
 288                                           BLOCK_DEVICE_IO_STATUS_FAILED;
 289     }
 290 }
 291
 292 void block_job_event_cancelled(BlockJob *job)
 293 {
 294     qapi_event_send_block_job_cancelled(job->driver->job_type,
 295                                         job->id,
 296                                         job->len,
 297                                         job->offset,
 298                                         job->speed,
 299                                         &error_abort);
 300 }
 301
 302 void block_job_event_completed(BlockJob *job, const char *msg)
 303 {
 304     qapi_event_send_block_job_completed(job->driver->job_type,
 305                                         job->id,
 306                                         job->len,
 307                                         job->offset,
 308                                         job->speed,
 309                                         !!msg,
 310                                         msg,
 311                                         &error_abort);
 312 }
 313
 314 void block_job_event_ready(BlockJob *job)
 315 {
 316     job->ready = true;
 317
 318     qapi_event_send_block_job_ready(job->driver->job_type,
 319                                     job->id,
 320                                     job->len,
 321                                     job->offset,
 322                                     job->speed, &error_abort);
 323 }
 324
 325 BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
 326                                         BlockdevOnError on_err,
 327                                         int is_read, int error)
 328 {
 329     BlockErrorAction action;
 330
 331     switch (on_err) {
 332     case BLOCKDEV_ON_ERROR_ENOSPC:
 333         action = (error == ENOSPC) ?
 334                  BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
 335         break;
 336     case BLOCKDEV_ON_ERROR_STOP:
 337         action = BLOCK_ERROR_ACTION_STOP;
 338         break;
 339     case BLOCKDEV_ON_ERROR_REPORT:
 340         action = BLOCK_ERROR_ACTION_REPORT;
 341         break;
 342     case BLOCKDEV_ON_ERROR_IGNORE:
 343         action = BLOCK_ERROR_ACTION_IGNORE;
 344         break;
 345     default:
 346         abort();
 347     }
 348     qapi_event_send_block_job_error(job->id,
 349                                     is_read ? IO_OPERATION_TYPE_READ :
 350                                     IO_OPERATION_TYPE_WRITE,
 351                                     action, &error_abort);
 352     if (action == BLOCK_ERROR_ACTION_STOP) {
 353         /* make the pause user visible, which will be resumed from QMP. */
 354         job->user_paused = true;
 355         block_job_pause(job);
 356         block_job_iostatus_set_err(job, error);
 357         if (bs != job->bs) {
 358             bdrv_iostatus_set_err(bs, error);
 359         }
 360     }
 361     return action;
 362 }
 363
 364 typedef struct {
 365     BlockJob *job;
 366     QEMUBH *bh;
 367     AioContext *aio_context;
 368     BlockJobDeferToMainLoopFn *fn;
 369     void *opaque;
 370 } BlockJobDeferToMainLoopData;
 371
 372 static void block_job_defer_to_main_loop_bh(void *opaque)
 373 {
 374     BlockJobDeferToMainLoopData *data = opaque;
 375     AioContext *aio_context;
 376
 377     qemu_bh_delete(data->bh);
 378
 379     /* Prevent race with block_job_defer_to_main_loop() */
 380     aio_context_acquire(data->aio_context);
 381
 382     /* Fetch BDS AioContext again, in case it has changed */
 383     aio_context = bdrv_get_aio_context(data->job->bs);
 384     aio_context_acquire(aio_context);
 385
 386     data->fn(data->job, data->opaque);
 387
 388     aio_context_release(aio_context);
 389
 390     aio_context_release(data->aio_context);
 391
 392     g_free(data);
 393 }
 394
 395 void block_job_defer_to_main_loop(BlockJob *job,
 396                                   BlockJobDeferToMainLoopFn *fn,
 397                                   void *opaque)
 398 {
 399     BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data));
 400     data->job = job;
 401     data->bh = qemu_bh_new(block_job_defer_to_main_loop_bh, data);
 402     data->aio_context = bdrv_get_aio_context(job->bs);
 403     data->fn = fn;
 404     data->opaque = opaque;
 405
 406     qemu_bh_schedule(data->bh);
 407 }