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 void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
  41                        int64_t speed, BlockCompletionFunc *cb,
  42                        void *opaque, Error **errp)
  43 {
  44     BlockJob *job;
  45
  46     if (bs->job) {
  47         error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
  48         return NULL;
  49     }
  50     bdrv_ref(bs);
  51     job = g_malloc0(driver->instance_size);
  52     error_setg(&job->blocker, "block device is in use by block job: %s",
  53                BlockJobType_lookup[driver->job_type]);
  54     bdrv_op_block_all(bs, job->blocker);
  55     bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
  56
  57     job->driver        = driver;
  58     job->id            = g_strdup(bdrv_get_device_name(bs));
  59     job->bs            = bs;
  60     job->cb            = cb;
  61     job->opaque        = opaque;
  62     job->busy          = true;
  63     job->refcnt        = 1;
  64     bs->job = job;
  65
  66     /* Only set speed when necessary to avoid NotSupported error */
  67     if (speed != 0) {
  68         Error *local_err = NULL;
  69
  70         block_job_set_speed(job, speed, &local_err);
  71         if (local_err) {
  72             block_job_unref(job);
  73             error_propagate(errp, local_err);
  74             return NULL;
  75         }
  76     }
  77     return job;
  78 }
  79
  80 void block_job_ref(BlockJob *job)
  81 {
  82     ++job->refcnt;
  83 }
  84
  85 void block_job_unref(BlockJob *job)
  86 {
  87     if (--job->refcnt == 0) {
  88         job->bs->job = NULL;
  89         bdrv_op_unblock_all(job->bs, job->blocker);
  90         bdrv_unref(job->bs);
  91         error_free(job->blocker);
  92         g_free(job->id);
  93         g_free(job);
  94     }
  95 }
  96
  97 void block_job_completed(BlockJob *job, int ret)
  98 {
  99     BlockDriverState *bs = job->bs;
 100
 101     assert(bs->job == job);
 102     assert(!job->completed);
 103     job->completed = true;
 104     job->ret = ret;
 105     job->cb(job->opaque, ret);
 106     block_job_unref(job);
 107 }
 108
 109 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
 110 {
 111     Error *local_err = NULL;
 112
 113     if (!job->driver->set_speed) {
 114         error_setg(errp, QERR_UNSUPPORTED);
 115         return;
 116     }
 117     job->driver->set_speed(job, speed, &local_err);
 118     if (local_err) {
 119         error_propagate(errp, local_err);
 120         return;
 121     }
 122
 123     job->speed = speed;
 124 }
 125
 126 void block_job_complete(BlockJob *job, Error **errp)
 127 {
 128     if (job->pause_count || job->cancelled || !job->driver->complete) {
 129         error_setg(errp, QERR_BLOCK_JOB_NOT_READY, job->id);
 130         return;
 131     }
 132
 133     job->driver->complete(job, errp);
 134 }
 135
 136 void block_job_pause(BlockJob *job)
 137 {
 138     job->pause_count++;
 139 }
 140
 141 bool block_job_is_paused(BlockJob *job)
 142 {
 143     return job->pause_count > 0;
 144 }
 145
 146 void block_job_resume(BlockJob *job)
 147 {
 148     assert(job->pause_count > 0);
 149     job->pause_count--;
 150     if (job->pause_count) {
 151         return;
 152     }
 153     block_job_enter(job);
 154 }
 155
 156 void block_job_enter(BlockJob *job)
 157 {
 158     block_job_iostatus_reset(job);
 159     if (job->co && !job->busy) {
 160         qemu_coroutine_enter(job->co, NULL);
 161     }
 162 }
 163
 164 void block_job_cancel(BlockJob *job)
 165 {
 166     job->cancelled = true;
 167     block_job_enter(job);
 168 }
 169
 170 bool block_job_is_cancelled(BlockJob *job)
 171 {
 172     return job->cancelled;
 173 }
 174
 175 void block_job_iostatus_reset(BlockJob *job)
 176 {
 177     job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
 178     if (job->driver->iostatus_reset) {
 179         job->driver->iostatus_reset(job);
 180     }
 181 }
 182
 183 struct BlockFinishData {
 184     BlockJob *job;
 185     BlockCompletionFunc *cb;
 186     void *opaque;
 187     bool cancelled;
 188     int ret;
 189 };
 190
 191 static void block_job_finish_cb(void *opaque, int ret)
 192 {
 193     struct BlockFinishData *data = opaque;
 194
 195     data->cancelled = block_job_is_cancelled(data->job);
 196     data->ret = ret;
 197     data->cb(data->opaque, ret);
 198 }
 199
 200 static int block_job_finish_sync(BlockJob *job,
 201                                  void (*finish)(BlockJob *, Error **errp),
 202                                  Error **errp)
 203 {
 204     struct BlockFinishData data;
 205     BlockDriverState *bs = job->bs;
 206     Error *local_err = NULL;
 207
 208     assert(bs->job == job);
 209
 210     /* Set up our own callback to store the result and chain to
 211      * the original callback.
 212      */
 213     data.job = job;
 214     data.cb = job->cb;
 215     data.opaque = job->opaque;
 216     data.ret = -EINPROGRESS;
 217     job->cb = block_job_finish_cb;
 218     job->opaque = &data;
 219     finish(job, &local_err);
 220     if (local_err) {
 221         error_propagate(errp, local_err);
 222         return -EBUSY;
 223     }
 224     while (data.ret == -EINPROGRESS) {
 225         aio_poll(bdrv_get_aio_context(bs), true);
 226     }
 227     return (data.cancelled && data.ret == 0) ? -ECANCELED : data.ret;
 228 }
 229
 230 /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be
 231  * used with block_job_finish_sync() without the need for (rather nasty)
 232  * function pointer casts there. */
 233 static void block_job_cancel_err(BlockJob *job, Error **errp)
 234 {
 235     block_job_cancel(job);
 236 }
 237
 238 int block_job_cancel_sync(BlockJob *job)
 239 {
 240     return block_job_finish_sync(job, &block_job_cancel_err, NULL);
 241 }
 242
 243 int block_job_complete_sync(BlockJob *job, Error **errp)
 244 {
 245     return block_job_finish_sync(job, &block_job_complete, errp);
 246 }
 247
 248 void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
 249 {
 250     assert(job->busy);
 251
 252     /* Check cancellation *before* setting busy = false, too!  */
 253     if (block_job_is_cancelled(job)) {
 254         return;
 255     }
 256
 257     job->busy = false;
 258     if (block_job_is_paused(job)) {
 259         qemu_coroutine_yield();
 260     } else {
 261         co_aio_sleep_ns(bdrv_get_aio_context(job->bs), type, ns);
 262     }
 263     job->busy = true;
 264 }
 265
 266 void block_job_yield(BlockJob *job)
 267 {
 268     assert(job->busy);
 269
 270     /* Check cancellation *before* setting busy = false, too!  */
 271     if (block_job_is_cancelled(job)) {
 272         return;
 273     }
 274
 275     job->busy = false;
 276     qemu_coroutine_yield();
 277     job->busy = true;
 278 }
 279
 280 BlockJobInfo *block_job_query(BlockJob *job)
 281 {
 282     BlockJobInfo *info = g_new0(BlockJobInfo, 1);
 283     info->type      = g_strdup(BlockJobType_lookup[job->driver->job_type]);
 284     info->device    = g_strdup(job->id);
 285     info->len       = job->len;
 286     info->busy      = job->busy;
 287     info->paused    = job->pause_count > 0;
 288     info->offset    = job->offset;
 289     info->speed     = job->speed;
 290     info->io_status = job->iostatus;
 291     info->ready     = job->ready;
 292     return info;
 293 }
 294
 295 static void block_job_iostatus_set_err(BlockJob *job, int error)
 296 {
 297     if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
 298         job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
 299                                           BLOCK_DEVICE_IO_STATUS_FAILED;
 300     }
 301 }
 302
 303 void block_job_event_cancelled(BlockJob *job)
 304 {
 305     qapi_event_send_block_job_cancelled(job->driver->job_type,
 306                                         job->id,
 307                                         job->len,
 308                                         job->offset,
 309                                         job->speed,
 310                                         &error_abort);
 311 }
 312
 313 void block_job_event_completed(BlockJob *job, const char *msg)
 314 {
 315     qapi_event_send_block_job_completed(job->driver->job_type,
 316                                         job->id,
 317                                         job->len,
 318                                         job->offset,
 319                                         job->speed,
 320                                         !!msg,
 321                                         msg,
 322                                         &error_abort);
 323 }
 324
 325 void block_job_event_ready(BlockJob *job)
 326 {
 327     job->ready = true;
 328
 329     qapi_event_send_block_job_ready(job->driver->job_type,
 330                                     job->id,
 331                                     job->len,
 332                                     job->offset,
 333                                     job->speed, &error_abort);
 334 }
 335
 336 BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
 337                                         BlockdevOnError on_err,
 338                                         int is_read, int error)
 339 {
 340     BlockErrorAction action;
 341
 342     switch (on_err) {
 343     case BLOCKDEV_ON_ERROR_ENOSPC:
 344         action = (error == ENOSPC) ?
 345                  BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
 346         break;
 347     case BLOCKDEV_ON_ERROR_STOP:
 348         action = BLOCK_ERROR_ACTION_STOP;
 349         break;
 350     case BLOCKDEV_ON_ERROR_REPORT:
 351         action = BLOCK_ERROR_ACTION_REPORT;
 352         break;
 353     case BLOCKDEV_ON_ERROR_IGNORE:
 354         action = BLOCK_ERROR_ACTION_IGNORE;
 355         break;
 356     default:
 357         abort();
 358     }
 359     qapi_event_send_block_job_error(job->id,
 360                                     is_read ? IO_OPERATION_TYPE_READ :
 361                                     IO_OPERATION_TYPE_WRITE,
 362                                     action, &error_abort);
 363     if (action == BLOCK_ERROR_ACTION_STOP) {
 364         /* make the pause user visible, which will be resumed from QMP. */
 365         job->user_paused = true;
 366         block_job_pause(job);
 367         block_job_iostatus_set_err(job, error);
 368         if (bs->blk && bs != job->bs) {
 369             blk_iostatus_set_err(bs->blk, error);
 370         }
 371     }
 372     return action;
 373 }
 374
 375 typedef struct {
 376     BlockJob *job;
 377     QEMUBH *bh;
 378     AioContext *aio_context;
 379     BlockJobDeferToMainLoopFn *fn;
 380     void *opaque;
 381 } BlockJobDeferToMainLoopData;
 382
 383 static void block_job_defer_to_main_loop_bh(void *opaque)
 384 {
 385     BlockJobDeferToMainLoopData *data = opaque;
 386     AioContext *aio_context;
 387
 388     qemu_bh_delete(data->bh);
 389
 390     /* Prevent race with block_job_defer_to_main_loop() */
 391     aio_context_acquire(data->aio_context);
 392
 393     /* Fetch BDS AioContext again, in case it has changed */
 394     aio_context = bdrv_get_aio_context(data->job->bs);
 395     aio_context_acquire(aio_context);
 396
 397     data->fn(data->job, data->opaque);
 398
 399     aio_context_release(aio_context);
 400
 401     aio_context_release(data->aio_context);
 402
 403     g_free(data);
 404 }
 405
 406 void block_job_defer_to_main_loop(BlockJob *job,
 407                                   BlockJobDeferToMainLoopFn *fn,
 408                                   void *opaque)
 409 {
 410     BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data));
 411     data->job = job;
 412     data->bh = qemu_bh_new(block_job_defer_to_main_loop_bh, data);
 413     data->aio_context = bdrv_get_aio_context(job->bs);
 414     data->fn = fn;
 415     data->opaque = opaque;
 416
 417     qemu_bh_schedule(data->bh);
 418 }