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