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