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 int block_job_finish_sync(BlockJob *job,
 192                                  void (*finish)(BlockJob *, Error **errp),
 193                                  Error **errp)
 194 {
 195     BlockDriverState *bs = job->bs;
 196     Error *local_err = NULL;
 197     int ret;
 198
 199     assert(bs->job == job);
 200
 201     block_job_ref(job);
 202     finish(job, &local_err);
 203     if (local_err) {
 204         error_propagate(errp, local_err);
 205         block_job_unref(job);
 206         return -EBUSY;
 207     }
 208     while (!job->completed) {
 209         aio_poll(bdrv_get_aio_context(bs), true);
 210     }
 211     ret = (job->cancelled && job->ret == 0) ? -ECANCELED : job->ret;
 212     block_job_unref(job);
 213     return ret;
 214 }
 215
 216 /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be
 217  * used with block_job_finish_sync() without the need for (rather nasty)
 218  * function pointer casts there. */
 219 static void block_job_cancel_err(BlockJob *job, Error **errp)
 220 {
 221     block_job_cancel(job);
 222 }
 223
 224 int block_job_cancel_sync(BlockJob *job)
 225 {
 226     return block_job_finish_sync(job, &block_job_cancel_err, NULL);
 227 }
 228
 229 int block_job_complete_sync(BlockJob *job, Error **errp)
 230 {
 231     return block_job_finish_sync(job, &block_job_complete, errp);
 232 }
 233
 234 void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
 235 {
 236     assert(job->busy);
 237
 238     /* Check cancellation *before* setting busy = false, too!  */
 239     if (block_job_is_cancelled(job)) {
 240         return;
 241     }
 242
 243     job->busy = false;
 244     if (block_job_is_paused(job)) {
 245         qemu_coroutine_yield();
 246     } else {
 247         co_aio_sleep_ns(bdrv_get_aio_context(job->bs), type, ns);
 248     }
 249     job->busy = true;
 250 }
 251
 252 void block_job_yield(BlockJob *job)
 253 {
 254     assert(job->busy);
 255
 256     /* Check cancellation *before* setting busy = false, too!  */
 257     if (block_job_is_cancelled(job)) {
 258         return;
 259     }
 260
 261     job->busy = false;
 262     qemu_coroutine_yield();
 263     job->busy = true;
 264 }
 265
 266 BlockJobInfo *block_job_query(BlockJob *job)
 267 {
 268     BlockJobInfo *info = g_new0(BlockJobInfo, 1);
 269     info->type      = g_strdup(BlockJobType_lookup[job->driver->job_type]);
 270     info->device    = g_strdup(job->id);
 271     info->len       = job->len;
 272     info->busy      = job->busy;
 273     info->paused    = job->pause_count > 0;
 274     info->offset    = job->offset;
 275     info->speed     = job->speed;
 276     info->io_status = job->iostatus;
 277     info->ready     = job->ready;
 278     return info;
 279 }
 280
 281 static void block_job_iostatus_set_err(BlockJob *job, int error)
 282 {
 283     if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
 284         job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
 285                                           BLOCK_DEVICE_IO_STATUS_FAILED;
 286     }
 287 }
 288
 289 void block_job_event_cancelled(BlockJob *job)
 290 {
 291     qapi_event_send_block_job_cancelled(job->driver->job_type,
 292                                         job->id,
 293                                         job->len,
 294                                         job->offset,
 295                                         job->speed,
 296                                         &error_abort);
 297 }
 298
 299 void block_job_event_completed(BlockJob *job, const char *msg)
 300 {
 301     qapi_event_send_block_job_completed(job->driver->job_type,
 302                                         job->id,
 303                                         job->len,
 304                                         job->offset,
 305                                         job->speed,
 306                                         !!msg,
 307                                         msg,
 308                                         &error_abort);
 309 }
 310
 311 void block_job_event_ready(BlockJob *job)
 312 {
 313     job->ready = true;
 314
 315     qapi_event_send_block_job_ready(job->driver->job_type,
 316                                     job->id,
 317                                     job->len,
 318                                     job->offset,
 319                                     job->speed, &error_abort);
 320 }
 321
 322 BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
 323                                         BlockdevOnError on_err,
 324                                         int is_read, int error)
 325 {
 326     BlockErrorAction action;
 327
 328     switch (on_err) {
 329     case BLOCKDEV_ON_ERROR_ENOSPC:
 330         action = (error == ENOSPC) ?
 331                  BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
 332         break;
 333     case BLOCKDEV_ON_ERROR_STOP:
 334         action = BLOCK_ERROR_ACTION_STOP;
 335         break;
 336     case BLOCKDEV_ON_ERROR_REPORT:
 337         action = BLOCK_ERROR_ACTION_REPORT;
 338         break;
 339     case BLOCKDEV_ON_ERROR_IGNORE:
 340         action = BLOCK_ERROR_ACTION_IGNORE;
 341         break;
 342     default:
 343         abort();
 344     }
 345     qapi_event_send_block_job_error(job->id,
 346                                     is_read ? IO_OPERATION_TYPE_READ :
 347                                     IO_OPERATION_TYPE_WRITE,
 348                                     action, &error_abort);
 349     if (action == BLOCK_ERROR_ACTION_STOP) {
 350         /* make the pause user visible, which will be resumed from QMP. */
 351         job->user_paused = true;
 352         block_job_pause(job);
 353         block_job_iostatus_set_err(job, error);
 354         if (bs->blk && bs != job->bs) {
 355             blk_iostatus_set_err(bs->blk, error);
 356         }
 357     }
 358     return action;
 359 }
 360
 361 typedef struct {
 362     BlockJob *job;
 363     QEMUBH *bh;
 364     AioContext *aio_context;
 365     BlockJobDeferToMainLoopFn *fn;
 366     void *opaque;
 367 } BlockJobDeferToMainLoopData;
 368
 369 static void block_job_defer_to_main_loop_bh(void *opaque)
 370 {
 371     BlockJobDeferToMainLoopData *data = opaque;
 372     AioContext *aio_context;
 373
 374     qemu_bh_delete(data->bh);
 375
 376     /* Prevent race with block_job_defer_to_main_loop() */
 377     aio_context_acquire(data->aio_context);
 378
 379     /* Fetch BDS AioContext again, in case it has changed */
 380     aio_context = bdrv_get_aio_context(data->job->bs);
 381     aio_context_acquire(aio_context);
 382
 383     data->fn(data->job, data->opaque);
 384
 385     aio_context_release(aio_context);
 386
 387     aio_context_release(data->aio_context);
 388
 389     g_free(data);
 390 }
 391
 392 void block_job_defer_to_main_loop(BlockJob *job,
 393                                   BlockJobDeferToMainLoopFn *fn,
 394                                   void *opaque)
 395 {
 396     BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data));
 397     data->job = job;
 398     data->bh = qemu_bh_new(block_job_defer_to_main_loop_bh, data);
 399     data->aio_context = bdrv_get_aio_context(job->bs);
 400     data->fn = fn;
 401     data->opaque = opaque;
 402
 403     qemu_bh_schedule(data->bh);
 404 }