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