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