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