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