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     bs->job = job;
  64
  65     /* Only set speed when necessary to avoid NotSupported error */
  66     if (speed != 0) {
  67         Error *local_err = NULL;
  68
  69         block_job_set_speed(job, speed, &local_err);
  70         if (local_err) {
  71             block_job_release(bs);
  72             error_propagate(errp, local_err);
  73             return NULL;
  74         }
  75     }
  76     return job;
  77 }
  78
  79 void block_job_release(BlockDriverState *bs)
  80 {
  81     BlockJob *job = bs->job;
  82
  83     bs->job = NULL;
  84     bdrv_op_unblock_all(bs, job->blocker);
  85     error_free(job->blocker);
  86     g_free(job->id);
  87     g_free(job);
  88 }
  89
  90 void block_job_completed(BlockJob *job, int ret)
  91 {
  92     BlockDriverState *bs = job->bs;
  93
  94     assert(bs->job == job);
  95     job->cb(job->opaque, ret);
  96     block_job_release(bs);
  97 }
  98
  99 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
 100 {
 101     Error *local_err = NULL;
 102
 103     if (!job->driver->set_speed) {
 104         error_setg(errp, QERR_UNSUPPORTED);
 105         return;
 106     }
 107     job->driver->set_speed(job, speed, &local_err);
 108     if (local_err) {
 109         error_propagate(errp, local_err);
 110         return;
 111     }
 112
 113     job->speed = speed;
 114 }
 115
 116 void block_job_complete(BlockJob *job, Error **errp)
 117 {
 118     if (job->pause_count || job->cancelled || !job->driver->complete) {
 119         error_setg(errp, QERR_BLOCK_JOB_NOT_READY, job->id);
 120         return;
 121     }
 122
 123     job->driver->complete(job, errp);
 124 }
 125
 126 void block_job_pause(BlockJob *job)
 127 {
 128     job->pause_count++;
 129 }
 130
 131 bool block_job_is_paused(BlockJob *job)
 132 {
 133     return job->pause_count > 0;
 134 }
 135
 136 void block_job_resume(BlockJob *job)
 137 {
 138     assert(job->pause_count > 0);
 139     job->pause_count--;
 140     if (job->pause_count) {
 141         return;
 142     }
 143     block_job_enter(job);
 144 }
 145
 146 void block_job_enter(BlockJob *job)
 147 {
 148     block_job_iostatus_reset(job);
 149     if (job->co && !job->busy) {
 150         qemu_coroutine_enter(job->co, NULL);
 151     }
 152 }
 153
 154 void block_job_cancel(BlockJob *job)
 155 {
 156     job->cancelled = true;
 157     block_job_enter(job);
 158 }
 159
 160 bool block_job_is_cancelled(BlockJob *job)
 161 {
 162     return job->cancelled;
 163 }
 164
 165 void block_job_iostatus_reset(BlockJob *job)
 166 {
 167     job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
 168     if (job->driver->iostatus_reset) {
 169         job->driver->iostatus_reset(job);
 170     }
 171 }
 172
 173 struct BlockFinishData {
 174     BlockJob *job;
 175     BlockCompletionFunc *cb;
 176     void *opaque;
 177     bool cancelled;
 178     int ret;
 179 };
 180
 181 static void block_job_finish_cb(void *opaque, int ret)
 182 {
 183     struct BlockFinishData *data = opaque;
 184
 185     data->cancelled = block_job_is_cancelled(data->job);
 186     data->ret = ret;
 187     data->cb(data->opaque, ret);
 188 }
 189
 190 static int block_job_finish_sync(BlockJob *job,
 191                                  void (*finish)(BlockJob *, Error **errp),
 192                                  Error **errp)
 193 {
 194     struct BlockFinishData data;
 195     BlockDriverState *bs = job->bs;
 196     Error *local_err = NULL;
 197
 198     assert(bs->job == job);
 199
 200     /* Set up our own callback to store the result and chain to
 201      * the original callback.
 202      */
 203     data.job = job;
 204     data.cb = job->cb;
 205     data.opaque = job->opaque;
 206     data.ret = -EINPROGRESS;
 207     job->cb = block_job_finish_cb;
 208     job->opaque = &data;
 209     finish(job, &local_err);
 210     if (local_err) {
 211         error_propagate(errp, local_err);
 212         return -EBUSY;
 213     }
 214     while (data.ret == -EINPROGRESS) {
 215         aio_poll(bdrv_get_aio_context(bs), true);
 216     }
 217     return (data.cancelled && data.ret == 0) ? -ECANCELED : data.ret;
 218 }
 219
 220 /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be
 221  * used with block_job_finish_sync() without the need for (rather nasty)
 222  * function pointer casts there. */
 223 static void block_job_cancel_err(BlockJob *job, Error **errp)
 224 {
 225     block_job_cancel(job);
 226 }
 227
 228 int block_job_cancel_sync(BlockJob *job)
 229 {
 230     return block_job_finish_sync(job, &block_job_cancel_err, NULL);
 231 }
 232
 233 int block_job_complete_sync(BlockJob *job, Error **errp)
 234 {
 235     return block_job_finish_sync(job, &block_job_complete, errp);
 236 }
 237
 238 void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
 239 {
 240     assert(job->busy);
 241
 242     /* Check cancellation *before* setting busy = false, too!  */
 243     if (block_job_is_cancelled(job)) {
 244         return;
 245     }
 246
 247     job->busy = false;
 248     if (block_job_is_paused(job)) {
 249         qemu_coroutine_yield();
 250     } else {
 251         co_aio_sleep_ns(bdrv_get_aio_context(job->bs), type, ns);
 252     }
 253     job->busy = true;
 254 }
 255
 256 void block_job_yield(BlockJob *job)
 257 {
 258     assert(job->busy);
 259
 260     /* Check cancellation *before* setting busy = false, too!  */
 261     if (block_job_is_cancelled(job)) {
 262         return;
 263     }
 264
 265     job->busy = false;
 266     qemu_coroutine_yield();
 267     job->busy = true;
 268 }
 269
 270 BlockJobInfo *block_job_query(BlockJob *job)
 271 {
 272     BlockJobInfo *info = g_new0(BlockJobInfo, 1);
 273     info->type      = g_strdup(BlockJobType_lookup[job->driver->job_type]);
 274     info->device    = g_strdup(job->id);
 275     info->len       = job->len;
 276     info->busy      = job->busy;
 277     info->paused    = job->pause_count > 0;
 278     info->offset    = job->offset;
 279     info->speed     = job->speed;
 280     info->io_status = job->iostatus;
 281     info->ready     = job->ready;
 282     return info;
 283 }
 284
 285 static void block_job_iostatus_set_err(BlockJob *job, int error)
 286 {
 287     if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
 288         job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
 289                                           BLOCK_DEVICE_IO_STATUS_FAILED;
 290     }
 291 }
 292
 293 void block_job_event_cancelled(BlockJob *job)
 294 {
 295     qapi_event_send_block_job_cancelled(job->driver->job_type,
 296                                         job->id,
 297                                         job->len,
 298                                         job->offset,
 299                                         job->speed,
 300                                         &error_abort);
 301 }
 302
 303 void block_job_event_completed(BlockJob *job, const char *msg)
 304 {
 305     qapi_event_send_block_job_completed(job->driver->job_type,
 306                                         job->id,
 307                                         job->len,
 308                                         job->offset,
 309                                         job->speed,
 310                                         !!msg,
 311                                         msg,
 312                                         &error_abort);
 313 }
 314
 315 void block_job_event_ready(BlockJob *job)
 316 {
 317     job->ready = true;
 318
 319     qapi_event_send_block_job_ready(job->driver->job_type,
 320                                     job->id,
 321                                     job->len,
 322                                     job->offset,
 323                                     job->speed, &error_abort);
 324 }
 325
 326 BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
 327                                         BlockdevOnError on_err,
 328                                         int is_read, int error)
 329 {
 330     BlockErrorAction action;
 331
 332     switch (on_err) {
 333     case BLOCKDEV_ON_ERROR_ENOSPC:
 334         action = (error == ENOSPC) ?
 335                  BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
 336         break;
 337     case BLOCKDEV_ON_ERROR_STOP:
 338         action = BLOCK_ERROR_ACTION_STOP;
 339         break;
 340     case BLOCKDEV_ON_ERROR_REPORT:
 341         action = BLOCK_ERROR_ACTION_REPORT;
 342         break;
 343     case BLOCKDEV_ON_ERROR_IGNORE:
 344         action = BLOCK_ERROR_ACTION_IGNORE;
 345         break;
 346     default:
 347         abort();
 348     }
 349     qapi_event_send_block_job_error(job->id,
 350                                     is_read ? IO_OPERATION_TYPE_READ :
 351                                     IO_OPERATION_TYPE_WRITE,
 352                                     action, &error_abort);
 353     if (action == BLOCK_ERROR_ACTION_STOP) {
 354         /* make the pause user visible, which will be resumed from QMP. */
 355         job->user_paused = true;
 356         block_job_pause(job);
 357         block_job_iostatus_set_err(job, error);
 358         if (bs->blk && bs != job->bs) {
 359             blk_iostatus_set_err(bs->blk, error);
 360         }
 361     }
 362     return action;
 363 }
 364
 365 typedef struct {
 366     BlockJob *job;
 367     QEMUBH *bh;
 368     AioContext *aio_context;
 369     BlockJobDeferToMainLoopFn *fn;
 370     void *opaque;
 371 } BlockJobDeferToMainLoopData;
 372
 373 static void block_job_defer_to_main_loop_bh(void *opaque)
 374 {
 375     BlockJobDeferToMainLoopData *data = opaque;
 376     AioContext *aio_context;
 377
 378     qemu_bh_delete(data->bh);
 379
 380     /* Prevent race with block_job_defer_to_main_loop() */
 381     aio_context_acquire(data->aio_context);
 382
 383     /* Fetch BDS AioContext again, in case it has changed */
 384     aio_context = bdrv_get_aio_context(data->job->bs);
 385     aio_context_acquire(aio_context);
 386
 387     data->fn(data->job, data->opaque);
 388
 389     aio_context_release(aio_context);
 390
 391     aio_context_release(data->aio_context);
 392
 393     g_free(data);
 394 }
 395
 396 void block_job_defer_to_main_loop(BlockJob *job,
 397                                   BlockJobDeferToMainLoopFn *fn,
 398                                   void *opaque)
 399 {
 400     BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data));
 401     data->job = job;
 402     data->bh = qemu_bh_new(block_job_defer_to_main_loop_bh, data);
 403     data->aio_context = bdrv_get_aio_context(job->bs);
 404     data->fn = fn;
 405     data->opaque = opaque;
 406
 407     qemu_bh_schedule(data->bh);
 408 }