xref: /openbmc/qemu/blockjob.c (revision f1f7e4bf) 
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 /* Transactional group of block jobs */
41 struct BlockJobTxn {
42 
43     /* Is this txn being cancelled? */
44     bool aborting;
45 
46     /* List of jobs */
47     QLIST_HEAD(, BlockJob) jobs;
48 
49     /* Reference count */
50     int refcnt;
51 };
52 
53 void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
54                        int64_t speed, BlockCompletionFunc *cb,
55                        void *opaque, Error **errp)
56 {
57     BlockJob *job;
58 
59     if (bs->job) {
60         error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
61         return NULL;
62     }
63     bdrv_ref(bs);
64     job = g_malloc0(driver->instance_size);
65     error_setg(&job->blocker, "block device is in use by block job: %s",
66                BlockJobType_lookup[driver->job_type]);
67     bdrv_op_block_all(bs, job->blocker);
68     bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
69 
70     job->driver        = driver;
71     job->id            = g_strdup(bdrv_get_device_name(bs));
72     job->bs            = bs;
73     job->cb            = cb;
74     job->opaque        = opaque;
75     job->busy          = true;
76     job->refcnt        = 1;
77     bs->job = job;
78 
79     /* Only set speed when necessary to avoid NotSupported error */
80     if (speed != 0) {
81         Error *local_err = NULL;
82 
83         block_job_set_speed(job, speed, &local_err);
84         if (local_err) {
85             block_job_unref(job);
86             error_propagate(errp, local_err);
87             return NULL;
88         }
89     }
90     return job;
91 }
92 
93 void block_job_ref(BlockJob *job)
94 {
95     ++job->refcnt;
96 }
97 
98 void block_job_unref(BlockJob *job)
99 {
100     if (--job->refcnt == 0) {
101         job->bs->job = NULL;
102         bdrv_op_unblock_all(job->bs, job->blocker);
103         bdrv_unref(job->bs);
104         error_free(job->blocker);
105         g_free(job->id);
106         g_free(job);
107     }
108 }
109 
110 static void block_job_completed_single(BlockJob *job)
111 {
112     if (!job->ret) {
113         if (job->driver->commit) {
114             job->driver->commit(job);
115         }
116     } else {
117         if (job->driver->abort) {
118             job->driver->abort(job);
119         }
120     }
121     job->cb(job->opaque, job->ret);
122     if (job->txn) {
123         block_job_txn_unref(job->txn);
124     }
125     block_job_unref(job);
126 }
127 
128 static void block_job_completed_txn_abort(BlockJob *job)
129 {
130     AioContext *ctx;
131     BlockJobTxn *txn = job->txn;
132     BlockJob *other_job, *next;
133 
134     if (txn->aborting) {
135         /*
136          * We are cancelled by another job, which will handle everything.
137          */
138         return;
139     }
140     txn->aborting = true;
141     /* We are the first failed job. Cancel other jobs. */
142     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
143         ctx = bdrv_get_aio_context(other_job->bs);
144         aio_context_acquire(ctx);
145     }
146     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
147         if (other_job == job || other_job->completed) {
148             /* Other jobs are "effectively" cancelled by us, set the status for
149              * them; this job, however, may or may not be cancelled, depending
150              * on the caller, so leave it. */
151             if (other_job != job) {
152                 other_job->cancelled = true;
153             }
154             continue;
155         }
156         block_job_cancel_sync(other_job);
157         assert(other_job->completed);
158     }
159     QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
160         ctx = bdrv_get_aio_context(other_job->bs);
161         block_job_completed_single(other_job);
162         aio_context_release(ctx);
163     }
164 }
165 
166 static void block_job_completed_txn_success(BlockJob *job)
167 {
168     AioContext *ctx;
169     BlockJobTxn *txn = job->txn;
170     BlockJob *other_job, *next;
171     /*
172      * Successful completion, see if there are other running jobs in this
173      * txn.
174      */
175     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
176         if (!other_job->completed) {
177             return;
178         }
179     }
180     /* We are the last completed job, commit the transaction. */
181     QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
182         ctx = bdrv_get_aio_context(other_job->bs);
183         aio_context_acquire(ctx);
184         assert(other_job->ret == 0);
185         block_job_completed_single(other_job);
186         aio_context_release(ctx);
187     }
188 }
189 
190 void block_job_completed(BlockJob *job, int ret)
191 {
192     BlockDriverState *bs = job->bs;
193 
194     assert(bs->job == job);
195     assert(!job->completed);
196     job->completed = true;
197     job->ret = ret;
198     if (!job->txn) {
199         block_job_completed_single(job);
200     } else if (ret < 0 || block_job_is_cancelled(job)) {
201         block_job_completed_txn_abort(job);
202     } else {
203         block_job_completed_txn_success(job);
204     }
205 }
206 
207 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
208 {
209     Error *local_err = NULL;
210 
211     if (!job->driver->set_speed) {
212         error_setg(errp, QERR_UNSUPPORTED);
213         return;
214     }
215     job->driver->set_speed(job, speed, &local_err);
216     if (local_err) {
217         error_propagate(errp, local_err);
218         return;
219     }
220 
221     job->speed = speed;
222 }
223 
224 void block_job_complete(BlockJob *job, Error **errp)
225 {
226     if (job->pause_count || job->cancelled || !job->driver->complete) {
227         error_setg(errp, QERR_BLOCK_JOB_NOT_READY, job->id);
228         return;
229     }
230 
231     job->driver->complete(job, errp);
232 }
233 
234 void block_job_pause(BlockJob *job)
235 {
236     job->pause_count++;
237 }
238 
239 bool block_job_is_paused(BlockJob *job)
240 {
241     return job->pause_count > 0;
242 }
243 
244 void block_job_resume(BlockJob *job)
245 {
246     assert(job->pause_count > 0);
247     job->pause_count--;
248     if (job->pause_count) {
249         return;
250     }
251     block_job_enter(job);
252 }
253 
254 void block_job_enter(BlockJob *job)
255 {
256     block_job_iostatus_reset(job);
257     if (job->co && !job->busy) {
258         qemu_coroutine_enter(job->co, NULL);
259     }
260 }
261 
262 void block_job_cancel(BlockJob *job)
263 {
264     job->cancelled = true;
265     block_job_enter(job);
266 }
267 
268 bool block_job_is_cancelled(BlockJob *job)
269 {
270     return job->cancelled;
271 }
272 
273 void block_job_iostatus_reset(BlockJob *job)
274 {
275     job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
276     if (job->driver->iostatus_reset) {
277         job->driver->iostatus_reset(job);
278     }
279 }
280 
281 struct BlockFinishData {
282     BlockJob *job;
283     BlockCompletionFunc *cb;
284     void *opaque;
285     bool cancelled;
286     int ret;
287 };
288 
289 static int block_job_finish_sync(BlockJob *job,
290                                  void (*finish)(BlockJob *, Error **errp),
291                                  Error **errp)
292 {
293     BlockDriverState *bs = job->bs;
294     Error *local_err = NULL;
295     int ret;
296 
297     assert(bs->job == job);
298 
299     block_job_ref(job);
300     finish(job, &local_err);
301     if (local_err) {
302         error_propagate(errp, local_err);
303         block_job_unref(job);
304         return -EBUSY;
305     }
306     while (!job->completed) {
307         aio_poll(bdrv_get_aio_context(bs), true);
308     }
309     ret = (job->cancelled && job->ret == 0) ? -ECANCELED : job->ret;
310     block_job_unref(job);
311     return ret;
312 }
313 
314 /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be
315  * used with block_job_finish_sync() without the need for (rather nasty)
316  * function pointer casts there. */
317 static void block_job_cancel_err(BlockJob *job, Error **errp)
318 {
319     block_job_cancel(job);
320 }
321 
322 int block_job_cancel_sync(BlockJob *job)
323 {
324     return block_job_finish_sync(job, &block_job_cancel_err, NULL);
325 }
326 
327 int block_job_complete_sync(BlockJob *job, Error **errp)
328 {
329     return block_job_finish_sync(job, &block_job_complete, errp);
330 }
331 
332 void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
333 {
334     assert(job->busy);
335 
336     /* Check cancellation *before* setting busy = false, too!  */
337     if (block_job_is_cancelled(job)) {
338         return;
339     }
340 
341     job->busy = false;
342     if (block_job_is_paused(job)) {
343         qemu_coroutine_yield();
344     } else {
345         co_aio_sleep_ns(bdrv_get_aio_context(job->bs), type, ns);
346     }
347     job->busy = true;
348 }
349 
350 void block_job_yield(BlockJob *job)
351 {
352     assert(job->busy);
353 
354     /* Check cancellation *before* setting busy = false, too!  */
355     if (block_job_is_cancelled(job)) {
356         return;
357     }
358 
359     job->busy = false;
360     qemu_coroutine_yield();
361     job->busy = true;
362 }
363 
364 BlockJobInfo *block_job_query(BlockJob *job)
365 {
366     BlockJobInfo *info = g_new0(BlockJobInfo, 1);
367     info->type      = g_strdup(BlockJobType_lookup[job->driver->job_type]);
368     info->device    = g_strdup(job->id);
369     info->len       = job->len;
370     info->busy      = job->busy;
371     info->paused    = job->pause_count > 0;
372     info->offset    = job->offset;
373     info->speed     = job->speed;
374     info->io_status = job->iostatus;
375     info->ready     = job->ready;
376     return info;
377 }
378 
379 static void block_job_iostatus_set_err(BlockJob *job, int error)
380 {
381     if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
382         job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
383                                           BLOCK_DEVICE_IO_STATUS_FAILED;
384     }
385 }
386 
387 void block_job_event_cancelled(BlockJob *job)
388 {
389     qapi_event_send_block_job_cancelled(job->driver->job_type,
390                                         job->id,
391                                         job->len,
392                                         job->offset,
393                                         job->speed,
394                                         &error_abort);
395 }
396 
397 void block_job_event_completed(BlockJob *job, const char *msg)
398 {
399     qapi_event_send_block_job_completed(job->driver->job_type,
400                                         job->id,
401                                         job->len,
402                                         job->offset,
403                                         job->speed,
404                                         !!msg,
405                                         msg,
406                                         &error_abort);
407 }
408 
409 void block_job_event_ready(BlockJob *job)
410 {
411     job->ready = true;
412 
413     qapi_event_send_block_job_ready(job->driver->job_type,
414                                     job->id,
415                                     job->len,
416                                     job->offset,
417                                     job->speed, &error_abort);
418 }
419 
420 BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
421                                         BlockdevOnError on_err,
422                                         int is_read, int error)
423 {
424     BlockErrorAction action;
425 
426     switch (on_err) {
427     case BLOCKDEV_ON_ERROR_ENOSPC:
428         action = (error == ENOSPC) ?
429                  BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
430         break;
431     case BLOCKDEV_ON_ERROR_STOP:
432         action = BLOCK_ERROR_ACTION_STOP;
433         break;
434     case BLOCKDEV_ON_ERROR_REPORT:
435         action = BLOCK_ERROR_ACTION_REPORT;
436         break;
437     case BLOCKDEV_ON_ERROR_IGNORE:
438         action = BLOCK_ERROR_ACTION_IGNORE;
439         break;
440     default:
441         abort();
442     }
443     qapi_event_send_block_job_error(job->id,
444                                     is_read ? IO_OPERATION_TYPE_READ :
445                                     IO_OPERATION_TYPE_WRITE,
446                                     action, &error_abort);
447     if (action == BLOCK_ERROR_ACTION_STOP) {
448         /* make the pause user visible, which will be resumed from QMP. */
449         job->user_paused = true;
450         block_job_pause(job);
451         block_job_iostatus_set_err(job, error);
452         if (bs->blk && bs != job->bs) {
453             blk_iostatus_set_err(bs->blk, error);
454         }
455     }
456     return action;
457 }
458 
459 typedef struct {
460     BlockJob *job;
461     QEMUBH *bh;
462     AioContext *aio_context;
463     BlockJobDeferToMainLoopFn *fn;
464     void *opaque;
465 } BlockJobDeferToMainLoopData;
466 
467 static void block_job_defer_to_main_loop_bh(void *opaque)
468 {
469     BlockJobDeferToMainLoopData *data = opaque;
470     AioContext *aio_context;
471 
472     qemu_bh_delete(data->bh);
473 
474     /* Prevent race with block_job_defer_to_main_loop() */
475     aio_context_acquire(data->aio_context);
476 
477     /* Fetch BDS AioContext again, in case it has changed */
478     aio_context = bdrv_get_aio_context(data->job->bs);
479     aio_context_acquire(aio_context);
480 
481     data->fn(data->job, data->opaque);
482 
483     aio_context_release(aio_context);
484 
485     aio_context_release(data->aio_context);
486 
487     g_free(data);
488 }
489 
490 void block_job_defer_to_main_loop(BlockJob *job,
491                                   BlockJobDeferToMainLoopFn *fn,
492                                   void *opaque)
493 {
494     BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data));
495     data->job = job;
496     data->bh = qemu_bh_new(block_job_defer_to_main_loop_bh, data);
497     data->aio_context = bdrv_get_aio_context(job->bs);
498     data->fn = fn;
499     data->opaque = opaque;
500 
501     qemu_bh_schedule(data->bh);
502 }
503 
504 BlockJobTxn *block_job_txn_new(void)
505 {
506     BlockJobTxn *txn = g_new0(BlockJobTxn, 1);
507     QLIST_INIT(&txn->jobs);
508     txn->refcnt = 1;
509     return txn;
510 }
511 
512 static void block_job_txn_ref(BlockJobTxn *txn)
513 {
514     txn->refcnt++;
515 }
516 
517 void block_job_txn_unref(BlockJobTxn *txn)
518 {
519     if (txn && --txn->refcnt == 0) {
520         g_free(txn);
521     }
522 }
523 
524 void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job)
525 {
526     if (!txn) {
527         return;
528     }
529 
530     assert(!job->txn);
531     job->txn = txn;
532 
533     QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
534     block_job_txn_ref(txn);
535 }
536