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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 "qemu/osdep.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 | static QLIST_HEAD(, BlockJob) block_jobs = QLIST_HEAD_INITIALIZER(block_jobs); | |
54 | ||
55 | BlockJob *block_job_next(BlockJob *job) | |
56 | { | |
57 | if (!job) { | |
58 | return QLIST_FIRST(&block_jobs); | |
59 | } | |
60 | return QLIST_NEXT(job, job_list); | |
61 | } | |
62 | ||
63 | /* Normally the job runs in its BlockBackend's AioContext. The exception is | |
64 | * block_job_defer_to_main_loop() where it runs in the QEMU main loop. Code | |
65 | * that supports both cases uses this helper function. | |
66 | */ | |
67 | static AioContext *block_job_get_aio_context(BlockJob *job) | |
68 | { | |
69 | return job->deferred_to_main_loop ? | |
70 | qemu_get_aio_context() : | |
71 | blk_get_aio_context(job->blk); | |
72 | } | |
73 | ||
74 | static void block_job_attached_aio_context(AioContext *new_context, | |
75 | void *opaque) | |
76 | { | |
77 | BlockJob *job = opaque; | |
78 | ||
79 | if (job->driver->attached_aio_context) { | |
80 | job->driver->attached_aio_context(job, new_context); | |
81 | } | |
82 | ||
83 | block_job_resume(job); | |
84 | } | |
85 | ||
86 | static void block_job_detach_aio_context(void *opaque) | |
87 | { | |
88 | BlockJob *job = opaque; | |
89 | ||
90 | /* In case the job terminates during aio_poll()... */ | |
91 | block_job_ref(job); | |
92 | ||
93 | block_job_pause(job); | |
94 | ||
95 | if (!job->paused) { | |
96 | /* If job is !job->busy this kicks it into the next pause point. */ | |
97 | block_job_enter(job); | |
98 | } | |
99 | while (!job->paused && !job->completed) { | |
100 | aio_poll(block_job_get_aio_context(job), true); | |
101 | } | |
102 | ||
103 | block_job_unref(job); | |
104 | } | |
105 | ||
106 | void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs, | |
107 | int64_t speed, BlockCompletionFunc *cb, | |
108 | void *opaque, Error **errp) | |
109 | { | |
110 | BlockBackend *blk; | |
111 | BlockJob *job; | |
112 | ||
113 | if (bs->job) { | |
114 | error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs)); | |
115 | return NULL; | |
116 | } | |
117 | ||
118 | blk = blk_new(); | |
119 | blk_insert_bs(blk, bs); | |
120 | ||
121 | job = g_malloc0(driver->instance_size); | |
122 | error_setg(&job->blocker, "block device is in use by block job: %s", | |
123 | BlockJobType_lookup[driver->job_type]); | |
124 | bdrv_op_block_all(bs, job->blocker); | |
125 | bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker); | |
126 | ||
127 | job->driver = driver; | |
128 | job->id = g_strdup(bdrv_get_device_name(bs)); | |
129 | job->blk = blk; | |
130 | job->cb = cb; | |
131 | job->opaque = opaque; | |
132 | job->busy = true; | |
133 | job->refcnt = 1; | |
134 | bs->job = job; | |
135 | ||
136 | QLIST_INSERT_HEAD(&block_jobs, job, job_list); | |
137 | ||
138 | blk_add_aio_context_notifier(blk, block_job_attached_aio_context, | |
139 | block_job_detach_aio_context, job); | |
140 | ||
141 | /* Only set speed when necessary to avoid NotSupported error */ | |
142 | if (speed != 0) { | |
143 | Error *local_err = NULL; | |
144 | ||
145 | block_job_set_speed(job, speed, &local_err); | |
146 | if (local_err) { | |
147 | block_job_unref(job); | |
148 | error_propagate(errp, local_err); | |
149 | return NULL; | |
150 | } | |
151 | } | |
152 | return job; | |
153 | } | |
154 | ||
155 | void block_job_ref(BlockJob *job) | |
156 | { | |
157 | ++job->refcnt; | |
158 | } | |
159 | ||
160 | void block_job_unref(BlockJob *job) | |
161 | { | |
162 | if (--job->refcnt == 0) { | |
163 | BlockDriverState *bs = blk_bs(job->blk); | |
164 | bs->job = NULL; | |
165 | bdrv_op_unblock_all(bs, job->blocker); | |
166 | blk_remove_aio_context_notifier(job->blk, | |
167 | block_job_attached_aio_context, | |
168 | block_job_detach_aio_context, job); | |
169 | blk_unref(job->blk); | |
170 | error_free(job->blocker); | |
171 | g_free(job->id); | |
172 | QLIST_REMOVE(job, job_list); | |
173 | g_free(job); | |
174 | } | |
175 | } | |
176 | ||
177 | static void block_job_completed_single(BlockJob *job) | |
178 | { | |
179 | if (!job->ret) { | |
180 | if (job->driver->commit) { | |
181 | job->driver->commit(job); | |
182 | } | |
183 | } else { | |
184 | if (job->driver->abort) { | |
185 | job->driver->abort(job); | |
186 | } | |
187 | } | |
188 | job->cb(job->opaque, job->ret); | |
189 | if (job->txn) { | |
190 | block_job_txn_unref(job->txn); | |
191 | } | |
192 | block_job_unref(job); | |
193 | } | |
194 | ||
195 | static void block_job_completed_txn_abort(BlockJob *job) | |
196 | { | |
197 | AioContext *ctx; | |
198 | BlockJobTxn *txn = job->txn; | |
199 | BlockJob *other_job, *next; | |
200 | ||
201 | if (txn->aborting) { | |
202 | /* | |
203 | * We are cancelled by another job, which will handle everything. | |
204 | */ | |
205 | return; | |
206 | } | |
207 | txn->aborting = true; | |
208 | /* We are the first failed job. Cancel other jobs. */ | |
209 | QLIST_FOREACH(other_job, &txn->jobs, txn_list) { | |
210 | ctx = blk_get_aio_context(other_job->blk); | |
211 | aio_context_acquire(ctx); | |
212 | } | |
213 | QLIST_FOREACH(other_job, &txn->jobs, txn_list) { | |
214 | if (other_job == job || other_job->completed) { | |
215 | /* Other jobs are "effectively" cancelled by us, set the status for | |
216 | * them; this job, however, may or may not be cancelled, depending | |
217 | * on the caller, so leave it. */ | |
218 | if (other_job != job) { | |
219 | other_job->cancelled = true; | |
220 | } | |
221 | continue; | |
222 | } | |
223 | block_job_cancel_sync(other_job); | |
224 | assert(other_job->completed); | |
225 | } | |
226 | QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) { | |
227 | ctx = blk_get_aio_context(other_job->blk); | |
228 | block_job_completed_single(other_job); | |
229 | aio_context_release(ctx); | |
230 | } | |
231 | } | |
232 | ||
233 | static void block_job_completed_txn_success(BlockJob *job) | |
234 | { | |
235 | AioContext *ctx; | |
236 | BlockJobTxn *txn = job->txn; | |
237 | BlockJob *other_job, *next; | |
238 | /* | |
239 | * Successful completion, see if there are other running jobs in this | |
240 | * txn. | |
241 | */ | |
242 | QLIST_FOREACH(other_job, &txn->jobs, txn_list) { | |
243 | if (!other_job->completed) { | |
244 | return; | |
245 | } | |
246 | } | |
247 | /* We are the last completed job, commit the transaction. */ | |
248 | QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) { | |
249 | ctx = blk_get_aio_context(other_job->blk); | |
250 | aio_context_acquire(ctx); | |
251 | assert(other_job->ret == 0); | |
252 | block_job_completed_single(other_job); | |
253 | aio_context_release(ctx); | |
254 | } | |
255 | } | |
256 | ||
257 | void block_job_completed(BlockJob *job, int ret) | |
258 | { | |
259 | assert(blk_bs(job->blk)->job == job); | |
260 | assert(!job->completed); | |
261 | job->completed = true; | |
262 | job->ret = ret; | |
263 | if (!job->txn) { | |
264 | block_job_completed_single(job); | |
265 | } else if (ret < 0 || block_job_is_cancelled(job)) { | |
266 | block_job_completed_txn_abort(job); | |
267 | } else { | |
268 | block_job_completed_txn_success(job); | |
269 | } | |
270 | } | |
271 | ||
272 | void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp) | |
273 | { | |
274 | Error *local_err = NULL; | |
275 | ||
276 | if (!job->driver->set_speed) { | |
277 | error_setg(errp, QERR_UNSUPPORTED); | |
278 | return; | |
279 | } | |
280 | job->driver->set_speed(job, speed, &local_err); | |
281 | if (local_err) { | |
282 | error_propagate(errp, local_err); | |
283 | return; | |
284 | } | |
285 | ||
286 | job->speed = speed; | |
287 | } | |
288 | ||
289 | void block_job_complete(BlockJob *job, Error **errp) | |
290 | { | |
291 | if (job->pause_count || job->cancelled || !job->driver->complete) { | |
292 | error_setg(errp, QERR_BLOCK_JOB_NOT_READY, job->id); | |
293 | return; | |
294 | } | |
295 | ||
296 | job->driver->complete(job, errp); | |
297 | } | |
298 | ||
299 | void block_job_pause(BlockJob *job) | |
300 | { | |
301 | job->pause_count++; | |
302 | } | |
303 | ||
304 | static bool block_job_should_pause(BlockJob *job) | |
305 | { | |
306 | return job->pause_count > 0; | |
307 | } | |
308 | ||
309 | void coroutine_fn block_job_pause_point(BlockJob *job) | |
310 | { | |
311 | if (!block_job_should_pause(job)) { | |
312 | return; | |
313 | } | |
314 | if (block_job_is_cancelled(job)) { | |
315 | return; | |
316 | } | |
317 | ||
318 | if (job->driver->pause) { | |
319 | job->driver->pause(job); | |
320 | } | |
321 | ||
322 | if (block_job_should_pause(job) && !block_job_is_cancelled(job)) { | |
323 | job->paused = true; | |
324 | job->busy = false; | |
325 | qemu_coroutine_yield(); /* wait for block_job_resume() */ | |
326 | job->busy = true; | |
327 | job->paused = false; | |
328 | } | |
329 | ||
330 | if (job->driver->resume) { | |
331 | job->driver->resume(job); | |
332 | } | |
333 | } | |
334 | ||
335 | void block_job_resume(BlockJob *job) | |
336 | { | |
337 | assert(job->pause_count > 0); | |
338 | job->pause_count--; | |
339 | if (job->pause_count) { | |
340 | return; | |
341 | } | |
342 | block_job_enter(job); | |
343 | } | |
344 | ||
345 | void block_job_enter(BlockJob *job) | |
346 | { | |
347 | if (job->co && !job->busy) { | |
348 | qemu_coroutine_enter(job->co, NULL); | |
349 | } | |
350 | } | |
351 | ||
352 | void block_job_cancel(BlockJob *job) | |
353 | { | |
354 | job->cancelled = true; | |
355 | block_job_iostatus_reset(job); | |
356 | block_job_enter(job); | |
357 | } | |
358 | ||
359 | bool block_job_is_cancelled(BlockJob *job) | |
360 | { | |
361 | return job->cancelled; | |
362 | } | |
363 | ||
364 | void block_job_iostatus_reset(BlockJob *job) | |
365 | { | |
366 | job->iostatus = BLOCK_DEVICE_IO_STATUS_OK; | |
367 | if (job->driver->iostatus_reset) { | |
368 | job->driver->iostatus_reset(job); | |
369 | } | |
370 | } | |
371 | ||
372 | static int block_job_finish_sync(BlockJob *job, | |
373 | void (*finish)(BlockJob *, Error **errp), | |
374 | Error **errp) | |
375 | { | |
376 | Error *local_err = NULL; | |
377 | int ret; | |
378 | ||
379 | assert(blk_bs(job->blk)->job == job); | |
380 | ||
381 | block_job_ref(job); | |
382 | finish(job, &local_err); | |
383 | if (local_err) { | |
384 | error_propagate(errp, local_err); | |
385 | block_job_unref(job); | |
386 | return -EBUSY; | |
387 | } | |
388 | while (!job->completed) { | |
389 | aio_poll(block_job_get_aio_context(job), true); | |
390 | } | |
391 | ret = (job->cancelled && job->ret == 0) ? -ECANCELED : job->ret; | |
392 | block_job_unref(job); | |
393 | return ret; | |
394 | } | |
395 | ||
396 | /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be | |
397 | * used with block_job_finish_sync() without the need for (rather nasty) | |
398 | * function pointer casts there. */ | |
399 | static void block_job_cancel_err(BlockJob *job, Error **errp) | |
400 | { | |
401 | block_job_cancel(job); | |
402 | } | |
403 | ||
404 | int block_job_cancel_sync(BlockJob *job) | |
405 | { | |
406 | return block_job_finish_sync(job, &block_job_cancel_err, NULL); | |
407 | } | |
408 | ||
409 | void block_job_cancel_sync_all(void) | |
410 | { | |
411 | BlockJob *job; | |
412 | AioContext *aio_context; | |
413 | ||
414 | while ((job = QLIST_FIRST(&block_jobs))) { | |
415 | aio_context = blk_get_aio_context(job->blk); | |
416 | aio_context_acquire(aio_context); | |
417 | block_job_cancel_sync(job); | |
418 | aio_context_release(aio_context); | |
419 | } | |
420 | } | |
421 | ||
422 | int block_job_complete_sync(BlockJob *job, Error **errp) | |
423 | { | |
424 | return block_job_finish_sync(job, &block_job_complete, errp); | |
425 | } | |
426 | ||
427 | void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns) | |
428 | { | |
429 | assert(job->busy); | |
430 | ||
431 | /* Check cancellation *before* setting busy = false, too! */ | |
432 | if (block_job_is_cancelled(job)) { | |
433 | return; | |
434 | } | |
435 | ||
436 | job->busy = false; | |
437 | if (!block_job_should_pause(job)) { | |
438 | co_aio_sleep_ns(blk_get_aio_context(job->blk), type, ns); | |
439 | } | |
440 | job->busy = true; | |
441 | ||
442 | block_job_pause_point(job); | |
443 | } | |
444 | ||
445 | void block_job_yield(BlockJob *job) | |
446 | { | |
447 | assert(job->busy); | |
448 | ||
449 | /* Check cancellation *before* setting busy = false, too! */ | |
450 | if (block_job_is_cancelled(job)) { | |
451 | return; | |
452 | } | |
453 | ||
454 | job->busy = false; | |
455 | if (!block_job_should_pause(job)) { | |
456 | qemu_coroutine_yield(); | |
457 | } | |
458 | job->busy = true; | |
459 | ||
460 | block_job_pause_point(job); | |
461 | } | |
462 | ||
463 | BlockJobInfo *block_job_query(BlockJob *job) | |
464 | { | |
465 | BlockJobInfo *info = g_new0(BlockJobInfo, 1); | |
466 | info->type = g_strdup(BlockJobType_lookup[job->driver->job_type]); | |
467 | info->device = g_strdup(job->id); | |
468 | info->len = job->len; | |
469 | info->busy = job->busy; | |
470 | info->paused = job->pause_count > 0; | |
471 | info->offset = job->offset; | |
472 | info->speed = job->speed; | |
473 | info->io_status = job->iostatus; | |
474 | info->ready = job->ready; | |
475 | return info; | |
476 | } | |
477 | ||
478 | static void block_job_iostatus_set_err(BlockJob *job, int error) | |
479 | { | |
480 | if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) { | |
481 | job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE : | |
482 | BLOCK_DEVICE_IO_STATUS_FAILED; | |
483 | } | |
484 | } | |
485 | ||
486 | void block_job_event_cancelled(BlockJob *job) | |
487 | { | |
488 | qapi_event_send_block_job_cancelled(job->driver->job_type, | |
489 | job->id, | |
490 | job->len, | |
491 | job->offset, | |
492 | job->speed, | |
493 | &error_abort); | |
494 | } | |
495 | ||
496 | void block_job_event_completed(BlockJob *job, const char *msg) | |
497 | { | |
498 | qapi_event_send_block_job_completed(job->driver->job_type, | |
499 | job->id, | |
500 | job->len, | |
501 | job->offset, | |
502 | job->speed, | |
503 | !!msg, | |
504 | msg, | |
505 | &error_abort); | |
506 | } | |
507 | ||
508 | void block_job_event_ready(BlockJob *job) | |
509 | { | |
510 | job->ready = true; | |
511 | ||
512 | qapi_event_send_block_job_ready(job->driver->job_type, | |
513 | job->id, | |
514 | job->len, | |
515 | job->offset, | |
516 | job->speed, &error_abort); | |
517 | } | |
518 | ||
519 | BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err, | |
520 | int is_read, int error) | |
521 | { | |
522 | BlockErrorAction action; | |
523 | ||
524 | switch (on_err) { | |
525 | case BLOCKDEV_ON_ERROR_ENOSPC: | |
526 | action = (error == ENOSPC) ? | |
527 | BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT; | |
528 | break; | |
529 | case BLOCKDEV_ON_ERROR_STOP: | |
530 | action = BLOCK_ERROR_ACTION_STOP; | |
531 | break; | |
532 | case BLOCKDEV_ON_ERROR_REPORT: | |
533 | action = BLOCK_ERROR_ACTION_REPORT; | |
534 | break; | |
535 | case BLOCKDEV_ON_ERROR_IGNORE: | |
536 | action = BLOCK_ERROR_ACTION_IGNORE; | |
537 | break; | |
538 | default: | |
539 | abort(); | |
540 | } | |
541 | qapi_event_send_block_job_error(job->id, | |
542 | is_read ? IO_OPERATION_TYPE_READ : | |
543 | IO_OPERATION_TYPE_WRITE, | |
544 | action, &error_abort); | |
545 | if (action == BLOCK_ERROR_ACTION_STOP) { | |
546 | /* make the pause user visible, which will be resumed from QMP. */ | |
547 | job->user_paused = true; | |
548 | block_job_pause(job); | |
549 | block_job_iostatus_set_err(job, error); | |
550 | } | |
551 | return action; | |
552 | } | |
553 | ||
554 | typedef struct { | |
555 | BlockJob *job; | |
556 | QEMUBH *bh; | |
557 | AioContext *aio_context; | |
558 | BlockJobDeferToMainLoopFn *fn; | |
559 | void *opaque; | |
560 | } BlockJobDeferToMainLoopData; | |
561 | ||
562 | static void block_job_defer_to_main_loop_bh(void *opaque) | |
563 | { | |
564 | BlockJobDeferToMainLoopData *data = opaque; | |
565 | AioContext *aio_context; | |
566 | ||
567 | qemu_bh_delete(data->bh); | |
568 | ||
569 | /* Prevent race with block_job_defer_to_main_loop() */ | |
570 | aio_context_acquire(data->aio_context); | |
571 | ||
572 | /* Fetch BDS AioContext again, in case it has changed */ | |
573 | aio_context = blk_get_aio_context(data->job->blk); | |
574 | aio_context_acquire(aio_context); | |
575 | ||
576 | data->job->deferred_to_main_loop = false; | |
577 | data->fn(data->job, data->opaque); | |
578 | ||
579 | aio_context_release(aio_context); | |
580 | ||
581 | aio_context_release(data->aio_context); | |
582 | ||
583 | g_free(data); | |
584 | } | |
585 | ||
586 | void block_job_defer_to_main_loop(BlockJob *job, | |
587 | BlockJobDeferToMainLoopFn *fn, | |
588 | void *opaque) | |
589 | { | |
590 | BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data)); | |
591 | data->job = job; | |
592 | data->bh = qemu_bh_new(block_job_defer_to_main_loop_bh, data); | |
593 | data->aio_context = blk_get_aio_context(job->blk); | |
594 | data->fn = fn; | |
595 | data->opaque = opaque; | |
596 | job->deferred_to_main_loop = true; | |
597 | ||
598 | qemu_bh_schedule(data->bh); | |
599 | } | |
600 | ||
601 | BlockJobTxn *block_job_txn_new(void) | |
602 | { | |
603 | BlockJobTxn *txn = g_new0(BlockJobTxn, 1); | |
604 | QLIST_INIT(&txn->jobs); | |
605 | txn->refcnt = 1; | |
606 | return txn; | |
607 | } | |
608 | ||
609 | static void block_job_txn_ref(BlockJobTxn *txn) | |
610 | { | |
611 | txn->refcnt++; | |
612 | } | |
613 | ||
614 | void block_job_txn_unref(BlockJobTxn *txn) | |
615 | { | |
616 | if (txn && --txn->refcnt == 0) { | |
617 | g_free(txn); | |
618 | } | |
619 | } | |
620 | ||
621 | void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job) | |
622 | { | |
623 | if (!txn) { | |
624 | return; | |
625 | } | |
626 | ||
627 | assert(!job->txn); | |
628 | job->txn = txn; | |
629 | ||
630 | QLIST_INSERT_HEAD(&txn->jobs, job, txn_list); | |
631 | block_job_txn_ref(txn); | |
632 | } |