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61007b31 SH |
1 | /* |
2 | * Block layer I/O functions | |
3 | * | |
4 | * Copyright (c) 2003 Fabrice Bellard | |
5 | * | |
6 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
7 | * of this software and associated documentation files (the "Software"), to deal | |
8 | * in the Software without restriction, including without limitation the rights | |
9 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
10 | * copies of the Software, and to permit persons to whom the Software is | |
11 | * furnished to do so, subject to the following conditions: | |
12 | * | |
13 | * The above copyright notice and this permission notice shall be included in | |
14 | * all copies or substantial portions of the Software. | |
15 | * | |
16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
17 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
19 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
20 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
21 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
22 | * THE SOFTWARE. | |
23 | */ | |
24 | ||
25 | #include "trace.h" | |
61007b31 SH |
26 | #include "block/blockjob.h" |
27 | #include "block/block_int.h" | |
76f4afb4 | 28 | #include "block/throttle-groups.h" |
d49b6836 | 29 | #include "qemu/error-report.h" |
61007b31 SH |
30 | |
31 | #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ | |
32 | ||
33 | static BlockAIOCB *bdrv_aio_readv_em(BlockDriverState *bs, | |
34 | int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, | |
35 | BlockCompletionFunc *cb, void *opaque); | |
36 | static BlockAIOCB *bdrv_aio_writev_em(BlockDriverState *bs, | |
37 | int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, | |
38 | BlockCompletionFunc *cb, void *opaque); | |
39 | static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs, | |
40 | int64_t sector_num, int nb_sectors, | |
41 | QEMUIOVector *iov); | |
42 | static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, | |
43 | int64_t sector_num, int nb_sectors, | |
44 | QEMUIOVector *iov); | |
45 | static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs, | |
46 | int64_t offset, unsigned int bytes, QEMUIOVector *qiov, | |
47 | BdrvRequestFlags flags); | |
48 | static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs, | |
49 | int64_t offset, unsigned int bytes, QEMUIOVector *qiov, | |
50 | BdrvRequestFlags flags); | |
51 | static BlockAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs, | |
52 | int64_t sector_num, | |
53 | QEMUIOVector *qiov, | |
54 | int nb_sectors, | |
55 | BdrvRequestFlags flags, | |
56 | BlockCompletionFunc *cb, | |
57 | void *opaque, | |
58 | bool is_write); | |
59 | static void coroutine_fn bdrv_co_do_rw(void *opaque); | |
60 | static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs, | |
61 | int64_t sector_num, int nb_sectors, BdrvRequestFlags flags); | |
62 | ||
63 | /* throttling disk I/O limits */ | |
64 | void bdrv_set_io_limits(BlockDriverState *bs, | |
65 | ThrottleConfig *cfg) | |
66 | { | |
67 | int i; | |
68 | ||
76f4afb4 | 69 | throttle_group_config(bs, cfg); |
61007b31 SH |
70 | |
71 | for (i = 0; i < 2; i++) { | |
72 | qemu_co_enter_next(&bs->throttled_reqs[i]); | |
73 | } | |
74 | } | |
75 | ||
76 | /* this function drain all the throttled IOs */ | |
77 | static bool bdrv_start_throttled_reqs(BlockDriverState *bs) | |
78 | { | |
79 | bool drained = false; | |
80 | bool enabled = bs->io_limits_enabled; | |
81 | int i; | |
82 | ||
83 | bs->io_limits_enabled = false; | |
84 | ||
85 | for (i = 0; i < 2; i++) { | |
86 | while (qemu_co_enter_next(&bs->throttled_reqs[i])) { | |
87 | drained = true; | |
88 | } | |
89 | } | |
90 | ||
91 | bs->io_limits_enabled = enabled; | |
92 | ||
93 | return drained; | |
94 | } | |
95 | ||
96 | void bdrv_io_limits_disable(BlockDriverState *bs) | |
97 | { | |
98 | bs->io_limits_enabled = false; | |
61007b31 | 99 | bdrv_start_throttled_reqs(bs); |
76f4afb4 | 100 | throttle_group_unregister_bs(bs); |
61007b31 SH |
101 | } |
102 | ||
103 | /* should be called before bdrv_set_io_limits if a limit is set */ | |
76f4afb4 | 104 | void bdrv_io_limits_enable(BlockDriverState *bs, const char *group) |
61007b31 | 105 | { |
61007b31 | 106 | assert(!bs->io_limits_enabled); |
76f4afb4 | 107 | throttle_group_register_bs(bs, group); |
61007b31 SH |
108 | bs->io_limits_enabled = true; |
109 | } | |
110 | ||
76f4afb4 | 111 | void bdrv_io_limits_update_group(BlockDriverState *bs, const char *group) |
61007b31 | 112 | { |
76f4afb4 AG |
113 | /* this bs is not part of any group */ |
114 | if (!bs->throttle_state) { | |
115 | return; | |
61007b31 SH |
116 | } |
117 | ||
76f4afb4 AG |
118 | /* this bs is a part of the same group than the one we want */ |
119 | if (!g_strcmp0(throttle_group_get_name(bs), group)) { | |
61007b31 SH |
120 | return; |
121 | } | |
122 | ||
76f4afb4 AG |
123 | /* need to change the group this bs belong to */ |
124 | bdrv_io_limits_disable(bs); | |
125 | bdrv_io_limits_enable(bs, group); | |
61007b31 SH |
126 | } |
127 | ||
128 | void bdrv_setup_io_funcs(BlockDriver *bdrv) | |
129 | { | |
130 | /* Block drivers without coroutine functions need emulation */ | |
131 | if (!bdrv->bdrv_co_readv) { | |
132 | bdrv->bdrv_co_readv = bdrv_co_readv_em; | |
133 | bdrv->bdrv_co_writev = bdrv_co_writev_em; | |
134 | ||
135 | /* bdrv_co_readv_em()/brdv_co_writev_em() work in terms of aio, so if | |
136 | * the block driver lacks aio we need to emulate that too. | |
137 | */ | |
138 | if (!bdrv->bdrv_aio_readv) { | |
139 | /* add AIO emulation layer */ | |
140 | bdrv->bdrv_aio_readv = bdrv_aio_readv_em; | |
141 | bdrv->bdrv_aio_writev = bdrv_aio_writev_em; | |
142 | } | |
143 | } | |
144 | } | |
145 | ||
146 | void bdrv_refresh_limits(BlockDriverState *bs, Error **errp) | |
147 | { | |
148 | BlockDriver *drv = bs->drv; | |
149 | Error *local_err = NULL; | |
150 | ||
151 | memset(&bs->bl, 0, sizeof(bs->bl)); | |
152 | ||
153 | if (!drv) { | |
154 | return; | |
155 | } | |
156 | ||
157 | /* Take some limits from the children as a default */ | |
158 | if (bs->file) { | |
159 | bdrv_refresh_limits(bs->file, &local_err); | |
160 | if (local_err) { | |
161 | error_propagate(errp, local_err); | |
162 | return; | |
163 | } | |
164 | bs->bl.opt_transfer_length = bs->file->bl.opt_transfer_length; | |
165 | bs->bl.max_transfer_length = bs->file->bl.max_transfer_length; | |
4196d2f0 | 166 | bs->bl.min_mem_alignment = bs->file->bl.min_mem_alignment; |
61007b31 SH |
167 | bs->bl.opt_mem_alignment = bs->file->bl.opt_mem_alignment; |
168 | } else { | |
4196d2f0 | 169 | bs->bl.min_mem_alignment = 512; |
459b4e66 | 170 | bs->bl.opt_mem_alignment = getpagesize(); |
61007b31 SH |
171 | } |
172 | ||
173 | if (bs->backing_hd) { | |
174 | bdrv_refresh_limits(bs->backing_hd, &local_err); | |
175 | if (local_err) { | |
176 | error_propagate(errp, local_err); | |
177 | return; | |
178 | } | |
179 | bs->bl.opt_transfer_length = | |
180 | MAX(bs->bl.opt_transfer_length, | |
181 | bs->backing_hd->bl.opt_transfer_length); | |
182 | bs->bl.max_transfer_length = | |
183 | MIN_NON_ZERO(bs->bl.max_transfer_length, | |
184 | bs->backing_hd->bl.max_transfer_length); | |
185 | bs->bl.opt_mem_alignment = | |
186 | MAX(bs->bl.opt_mem_alignment, | |
187 | bs->backing_hd->bl.opt_mem_alignment); | |
4196d2f0 DL |
188 | bs->bl.min_mem_alignment = |
189 | MAX(bs->bl.min_mem_alignment, | |
190 | bs->backing_hd->bl.min_mem_alignment); | |
61007b31 SH |
191 | } |
192 | ||
193 | /* Then let the driver override it */ | |
194 | if (drv->bdrv_refresh_limits) { | |
195 | drv->bdrv_refresh_limits(bs, errp); | |
196 | } | |
197 | } | |
198 | ||
199 | /** | |
200 | * The copy-on-read flag is actually a reference count so multiple users may | |
201 | * use the feature without worrying about clobbering its previous state. | |
202 | * Copy-on-read stays enabled until all users have called to disable it. | |
203 | */ | |
204 | void bdrv_enable_copy_on_read(BlockDriverState *bs) | |
205 | { | |
206 | bs->copy_on_read++; | |
207 | } | |
208 | ||
209 | void bdrv_disable_copy_on_read(BlockDriverState *bs) | |
210 | { | |
211 | assert(bs->copy_on_read > 0); | |
212 | bs->copy_on_read--; | |
213 | } | |
214 | ||
215 | /* Check if any requests are in-flight (including throttled requests) */ | |
216 | static bool bdrv_requests_pending(BlockDriverState *bs) | |
217 | { | |
218 | if (!QLIST_EMPTY(&bs->tracked_requests)) { | |
219 | return true; | |
220 | } | |
221 | if (!qemu_co_queue_empty(&bs->throttled_reqs[0])) { | |
222 | return true; | |
223 | } | |
224 | if (!qemu_co_queue_empty(&bs->throttled_reqs[1])) { | |
225 | return true; | |
226 | } | |
227 | if (bs->file && bdrv_requests_pending(bs->file)) { | |
228 | return true; | |
229 | } | |
230 | if (bs->backing_hd && bdrv_requests_pending(bs->backing_hd)) { | |
231 | return true; | |
232 | } | |
233 | return false; | |
234 | } | |
235 | ||
236 | static bool bdrv_drain_one(BlockDriverState *bs) | |
237 | { | |
238 | bool bs_busy; | |
239 | ||
240 | bdrv_flush_io_queue(bs); | |
241 | bdrv_start_throttled_reqs(bs); | |
242 | bs_busy = bdrv_requests_pending(bs); | |
243 | bs_busy |= aio_poll(bdrv_get_aio_context(bs), bs_busy); | |
244 | return bs_busy; | |
245 | } | |
246 | ||
247 | /* | |
248 | * Wait for pending requests to complete on a single BlockDriverState subtree | |
249 | * | |
250 | * See the warning in bdrv_drain_all(). This function can only be called if | |
251 | * you are sure nothing can generate I/O because you have op blockers | |
252 | * installed. | |
253 | * | |
254 | * Note that unlike bdrv_drain_all(), the caller must hold the BlockDriverState | |
255 | * AioContext. | |
256 | */ | |
257 | void bdrv_drain(BlockDriverState *bs) | |
258 | { | |
259 | while (bdrv_drain_one(bs)) { | |
260 | /* Keep iterating */ | |
261 | } | |
262 | } | |
263 | ||
264 | /* | |
265 | * Wait for pending requests to complete across all BlockDriverStates | |
266 | * | |
267 | * This function does not flush data to disk, use bdrv_flush_all() for that | |
268 | * after calling this function. | |
269 | * | |
270 | * Note that completion of an asynchronous I/O operation can trigger any | |
271 | * number of other I/O operations on other devices---for example a coroutine | |
272 | * can be arbitrarily complex and a constant flow of I/O can come until the | |
273 | * coroutine is complete. Because of this, it is not possible to have a | |
274 | * function to drain a single device's I/O queue. | |
275 | */ | |
276 | void bdrv_drain_all(void) | |
277 | { | |
278 | /* Always run first iteration so any pending completion BHs run */ | |
279 | bool busy = true; | |
280 | BlockDriverState *bs = NULL; | |
281 | ||
282 | while ((bs = bdrv_next(bs))) { | |
283 | AioContext *aio_context = bdrv_get_aio_context(bs); | |
284 | ||
285 | aio_context_acquire(aio_context); | |
286 | if (bs->job) { | |
287 | block_job_pause(bs->job); | |
288 | } | |
289 | aio_context_release(aio_context); | |
290 | } | |
291 | ||
292 | while (busy) { | |
293 | busy = false; | |
294 | bs = NULL; | |
295 | ||
296 | while ((bs = bdrv_next(bs))) { | |
297 | AioContext *aio_context = bdrv_get_aio_context(bs); | |
298 | ||
299 | aio_context_acquire(aio_context); | |
300 | busy |= bdrv_drain_one(bs); | |
301 | aio_context_release(aio_context); | |
302 | } | |
303 | } | |
304 | ||
305 | bs = NULL; | |
306 | while ((bs = bdrv_next(bs))) { | |
307 | AioContext *aio_context = bdrv_get_aio_context(bs); | |
308 | ||
309 | aio_context_acquire(aio_context); | |
310 | if (bs->job) { | |
311 | block_job_resume(bs->job); | |
312 | } | |
313 | aio_context_release(aio_context); | |
314 | } | |
315 | } | |
316 | ||
317 | /** | |
318 | * Remove an active request from the tracked requests list | |
319 | * | |
320 | * This function should be called when a tracked request is completing. | |
321 | */ | |
322 | static void tracked_request_end(BdrvTrackedRequest *req) | |
323 | { | |
324 | if (req->serialising) { | |
325 | req->bs->serialising_in_flight--; | |
326 | } | |
327 | ||
328 | QLIST_REMOVE(req, list); | |
329 | qemu_co_queue_restart_all(&req->wait_queue); | |
330 | } | |
331 | ||
332 | /** | |
333 | * Add an active request to the tracked requests list | |
334 | */ | |
335 | static void tracked_request_begin(BdrvTrackedRequest *req, | |
336 | BlockDriverState *bs, | |
337 | int64_t offset, | |
338 | unsigned int bytes, bool is_write) | |
339 | { | |
340 | *req = (BdrvTrackedRequest){ | |
341 | .bs = bs, | |
342 | .offset = offset, | |
343 | .bytes = bytes, | |
344 | .is_write = is_write, | |
345 | .co = qemu_coroutine_self(), | |
346 | .serialising = false, | |
347 | .overlap_offset = offset, | |
348 | .overlap_bytes = bytes, | |
349 | }; | |
350 | ||
351 | qemu_co_queue_init(&req->wait_queue); | |
352 | ||
353 | QLIST_INSERT_HEAD(&bs->tracked_requests, req, list); | |
354 | } | |
355 | ||
356 | static void mark_request_serialising(BdrvTrackedRequest *req, uint64_t align) | |
357 | { | |
358 | int64_t overlap_offset = req->offset & ~(align - 1); | |
359 | unsigned int overlap_bytes = ROUND_UP(req->offset + req->bytes, align) | |
360 | - overlap_offset; | |
361 | ||
362 | if (!req->serialising) { | |
363 | req->bs->serialising_in_flight++; | |
364 | req->serialising = true; | |
365 | } | |
366 | ||
367 | req->overlap_offset = MIN(req->overlap_offset, overlap_offset); | |
368 | req->overlap_bytes = MAX(req->overlap_bytes, overlap_bytes); | |
369 | } | |
370 | ||
371 | /** | |
372 | * Round a region to cluster boundaries | |
373 | */ | |
374 | void bdrv_round_to_clusters(BlockDriverState *bs, | |
375 | int64_t sector_num, int nb_sectors, | |
376 | int64_t *cluster_sector_num, | |
377 | int *cluster_nb_sectors) | |
378 | { | |
379 | BlockDriverInfo bdi; | |
380 | ||
381 | if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) { | |
382 | *cluster_sector_num = sector_num; | |
383 | *cluster_nb_sectors = nb_sectors; | |
384 | } else { | |
385 | int64_t c = bdi.cluster_size / BDRV_SECTOR_SIZE; | |
386 | *cluster_sector_num = QEMU_ALIGN_DOWN(sector_num, c); | |
387 | *cluster_nb_sectors = QEMU_ALIGN_UP(sector_num - *cluster_sector_num + | |
388 | nb_sectors, c); | |
389 | } | |
390 | } | |
391 | ||
392 | static int bdrv_get_cluster_size(BlockDriverState *bs) | |
393 | { | |
394 | BlockDriverInfo bdi; | |
395 | int ret; | |
396 | ||
397 | ret = bdrv_get_info(bs, &bdi); | |
398 | if (ret < 0 || bdi.cluster_size == 0) { | |
399 | return bs->request_alignment; | |
400 | } else { | |
401 | return bdi.cluster_size; | |
402 | } | |
403 | } | |
404 | ||
405 | static bool tracked_request_overlaps(BdrvTrackedRequest *req, | |
406 | int64_t offset, unsigned int bytes) | |
407 | { | |
408 | /* aaaa bbbb */ | |
409 | if (offset >= req->overlap_offset + req->overlap_bytes) { | |
410 | return false; | |
411 | } | |
412 | /* bbbb aaaa */ | |
413 | if (req->overlap_offset >= offset + bytes) { | |
414 | return false; | |
415 | } | |
416 | return true; | |
417 | } | |
418 | ||
419 | static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self) | |
420 | { | |
421 | BlockDriverState *bs = self->bs; | |
422 | BdrvTrackedRequest *req; | |
423 | bool retry; | |
424 | bool waited = false; | |
425 | ||
426 | if (!bs->serialising_in_flight) { | |
427 | return false; | |
428 | } | |
429 | ||
430 | do { | |
431 | retry = false; | |
432 | QLIST_FOREACH(req, &bs->tracked_requests, list) { | |
433 | if (req == self || (!req->serialising && !self->serialising)) { | |
434 | continue; | |
435 | } | |
436 | if (tracked_request_overlaps(req, self->overlap_offset, | |
437 | self->overlap_bytes)) | |
438 | { | |
439 | /* Hitting this means there was a reentrant request, for | |
440 | * example, a block driver issuing nested requests. This must | |
441 | * never happen since it means deadlock. | |
442 | */ | |
443 | assert(qemu_coroutine_self() != req->co); | |
444 | ||
445 | /* If the request is already (indirectly) waiting for us, or | |
446 | * will wait for us as soon as it wakes up, then just go on | |
447 | * (instead of producing a deadlock in the former case). */ | |
448 | if (!req->waiting_for) { | |
449 | self->waiting_for = req; | |
450 | qemu_co_queue_wait(&req->wait_queue); | |
451 | self->waiting_for = NULL; | |
452 | retry = true; | |
453 | waited = true; | |
454 | break; | |
455 | } | |
456 | } | |
457 | } | |
458 | } while (retry); | |
459 | ||
460 | return waited; | |
461 | } | |
462 | ||
463 | static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset, | |
464 | size_t size) | |
465 | { | |
466 | if (size > BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS) { | |
467 | return -EIO; | |
468 | } | |
469 | ||
470 | if (!bdrv_is_inserted(bs)) { | |
471 | return -ENOMEDIUM; | |
472 | } | |
473 | ||
474 | if (offset < 0) { | |
475 | return -EIO; | |
476 | } | |
477 | ||
478 | return 0; | |
479 | } | |
480 | ||
481 | static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num, | |
482 | int nb_sectors) | |
483 | { | |
484 | if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) { | |
485 | return -EIO; | |
486 | } | |
487 | ||
488 | return bdrv_check_byte_request(bs, sector_num * BDRV_SECTOR_SIZE, | |
489 | nb_sectors * BDRV_SECTOR_SIZE); | |
490 | } | |
491 | ||
492 | typedef struct RwCo { | |
493 | BlockDriverState *bs; | |
494 | int64_t offset; | |
495 | QEMUIOVector *qiov; | |
496 | bool is_write; | |
497 | int ret; | |
498 | BdrvRequestFlags flags; | |
499 | } RwCo; | |
500 | ||
501 | static void coroutine_fn bdrv_rw_co_entry(void *opaque) | |
502 | { | |
503 | RwCo *rwco = opaque; | |
504 | ||
505 | if (!rwco->is_write) { | |
506 | rwco->ret = bdrv_co_do_preadv(rwco->bs, rwco->offset, | |
507 | rwco->qiov->size, rwco->qiov, | |
508 | rwco->flags); | |
509 | } else { | |
510 | rwco->ret = bdrv_co_do_pwritev(rwco->bs, rwco->offset, | |
511 | rwco->qiov->size, rwco->qiov, | |
512 | rwco->flags); | |
513 | } | |
514 | } | |
515 | ||
516 | /* | |
517 | * Process a vectored synchronous request using coroutines | |
518 | */ | |
519 | static int bdrv_prwv_co(BlockDriverState *bs, int64_t offset, | |
520 | QEMUIOVector *qiov, bool is_write, | |
521 | BdrvRequestFlags flags) | |
522 | { | |
523 | Coroutine *co; | |
524 | RwCo rwco = { | |
525 | .bs = bs, | |
526 | .offset = offset, | |
527 | .qiov = qiov, | |
528 | .is_write = is_write, | |
529 | .ret = NOT_DONE, | |
530 | .flags = flags, | |
531 | }; | |
532 | ||
533 | /** | |
534 | * In sync call context, when the vcpu is blocked, this throttling timer | |
535 | * will not fire; so the I/O throttling function has to be disabled here | |
536 | * if it has been enabled. | |
537 | */ | |
538 | if (bs->io_limits_enabled) { | |
539 | fprintf(stderr, "Disabling I/O throttling on '%s' due " | |
540 | "to synchronous I/O.\n", bdrv_get_device_name(bs)); | |
541 | bdrv_io_limits_disable(bs); | |
542 | } | |
543 | ||
544 | if (qemu_in_coroutine()) { | |
545 | /* Fast-path if already in coroutine context */ | |
546 | bdrv_rw_co_entry(&rwco); | |
547 | } else { | |
548 | AioContext *aio_context = bdrv_get_aio_context(bs); | |
549 | ||
550 | co = qemu_coroutine_create(bdrv_rw_co_entry); | |
551 | qemu_coroutine_enter(co, &rwco); | |
552 | while (rwco.ret == NOT_DONE) { | |
553 | aio_poll(aio_context, true); | |
554 | } | |
555 | } | |
556 | return rwco.ret; | |
557 | } | |
558 | ||
559 | /* | |
560 | * Process a synchronous request using coroutines | |
561 | */ | |
562 | static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, | |
563 | int nb_sectors, bool is_write, BdrvRequestFlags flags) | |
564 | { | |
565 | QEMUIOVector qiov; | |
566 | struct iovec iov = { | |
567 | .iov_base = (void *)buf, | |
568 | .iov_len = nb_sectors * BDRV_SECTOR_SIZE, | |
569 | }; | |
570 | ||
571 | if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) { | |
572 | return -EINVAL; | |
573 | } | |
574 | ||
575 | qemu_iovec_init_external(&qiov, &iov, 1); | |
576 | return bdrv_prwv_co(bs, sector_num << BDRV_SECTOR_BITS, | |
577 | &qiov, is_write, flags); | |
578 | } | |
579 | ||
580 | /* return < 0 if error. See bdrv_write() for the return codes */ | |
581 | int bdrv_read(BlockDriverState *bs, int64_t sector_num, | |
582 | uint8_t *buf, int nb_sectors) | |
583 | { | |
584 | return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false, 0); | |
585 | } | |
586 | ||
587 | /* Just like bdrv_read(), but with I/O throttling temporarily disabled */ | |
588 | int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num, | |
589 | uint8_t *buf, int nb_sectors) | |
590 | { | |
591 | bool enabled; | |
592 | int ret; | |
593 | ||
594 | enabled = bs->io_limits_enabled; | |
595 | bs->io_limits_enabled = false; | |
596 | ret = bdrv_read(bs, sector_num, buf, nb_sectors); | |
597 | bs->io_limits_enabled = enabled; | |
598 | return ret; | |
599 | } | |
600 | ||
601 | /* Return < 0 if error. Important errors are: | |
602 | -EIO generic I/O error (may happen for all errors) | |
603 | -ENOMEDIUM No media inserted. | |
604 | -EINVAL Invalid sector number or nb_sectors | |
605 | -EACCES Trying to write a read-only device | |
606 | */ | |
607 | int bdrv_write(BlockDriverState *bs, int64_t sector_num, | |
608 | const uint8_t *buf, int nb_sectors) | |
609 | { | |
610 | return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true, 0); | |
611 | } | |
612 | ||
613 | int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, | |
614 | int nb_sectors, BdrvRequestFlags flags) | |
615 | { | |
616 | return bdrv_rw_co(bs, sector_num, NULL, nb_sectors, true, | |
617 | BDRV_REQ_ZERO_WRITE | flags); | |
618 | } | |
619 | ||
620 | /* | |
621 | * Completely zero out a block device with the help of bdrv_write_zeroes. | |
622 | * The operation is sped up by checking the block status and only writing | |
623 | * zeroes to the device if they currently do not return zeroes. Optional | |
624 | * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP). | |
625 | * | |
626 | * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). | |
627 | */ | |
628 | int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags) | |
629 | { | |
630 | int64_t target_sectors, ret, nb_sectors, sector_num = 0; | |
631 | int n; | |
632 | ||
633 | target_sectors = bdrv_nb_sectors(bs); | |
634 | if (target_sectors < 0) { | |
635 | return target_sectors; | |
636 | } | |
637 | ||
638 | for (;;) { | |
639 | nb_sectors = MIN(target_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS); | |
640 | if (nb_sectors <= 0) { | |
641 | return 0; | |
642 | } | |
643 | ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n); | |
644 | if (ret < 0) { | |
645 | error_report("error getting block status at sector %" PRId64 ": %s", | |
646 | sector_num, strerror(-ret)); | |
647 | return ret; | |
648 | } | |
649 | if (ret & BDRV_BLOCK_ZERO) { | |
650 | sector_num += n; | |
651 | continue; | |
652 | } | |
653 | ret = bdrv_write_zeroes(bs, sector_num, n, flags); | |
654 | if (ret < 0) { | |
655 | error_report("error writing zeroes at sector %" PRId64 ": %s", | |
656 | sector_num, strerror(-ret)); | |
657 | return ret; | |
658 | } | |
659 | sector_num += n; | |
660 | } | |
661 | } | |
662 | ||
663 | int bdrv_pread(BlockDriverState *bs, int64_t offset, void *buf, int bytes) | |
664 | { | |
665 | QEMUIOVector qiov; | |
666 | struct iovec iov = { | |
667 | .iov_base = (void *)buf, | |
668 | .iov_len = bytes, | |
669 | }; | |
670 | int ret; | |
671 | ||
672 | if (bytes < 0) { | |
673 | return -EINVAL; | |
674 | } | |
675 | ||
676 | qemu_iovec_init_external(&qiov, &iov, 1); | |
677 | ret = bdrv_prwv_co(bs, offset, &qiov, false, 0); | |
678 | if (ret < 0) { | |
679 | return ret; | |
680 | } | |
681 | ||
682 | return bytes; | |
683 | } | |
684 | ||
685 | int bdrv_pwritev(BlockDriverState *bs, int64_t offset, QEMUIOVector *qiov) | |
686 | { | |
687 | int ret; | |
688 | ||
689 | ret = bdrv_prwv_co(bs, offset, qiov, true, 0); | |
690 | if (ret < 0) { | |
691 | return ret; | |
692 | } | |
693 | ||
694 | return qiov->size; | |
695 | } | |
696 | ||
697 | int bdrv_pwrite(BlockDriverState *bs, int64_t offset, | |
698 | const void *buf, int bytes) | |
699 | { | |
700 | QEMUIOVector qiov; | |
701 | struct iovec iov = { | |
702 | .iov_base = (void *) buf, | |
703 | .iov_len = bytes, | |
704 | }; | |
705 | ||
706 | if (bytes < 0) { | |
707 | return -EINVAL; | |
708 | } | |
709 | ||
710 | qemu_iovec_init_external(&qiov, &iov, 1); | |
711 | return bdrv_pwritev(bs, offset, &qiov); | |
712 | } | |
713 | ||
714 | /* | |
715 | * Writes to the file and ensures that no writes are reordered across this | |
716 | * request (acts as a barrier) | |
717 | * | |
718 | * Returns 0 on success, -errno in error cases. | |
719 | */ | |
720 | int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset, | |
721 | const void *buf, int count) | |
722 | { | |
723 | int ret; | |
724 | ||
725 | ret = bdrv_pwrite(bs, offset, buf, count); | |
726 | if (ret < 0) { | |
727 | return ret; | |
728 | } | |
729 | ||
730 | /* No flush needed for cache modes that already do it */ | |
731 | if (bs->enable_write_cache) { | |
732 | bdrv_flush(bs); | |
733 | } | |
734 | ||
735 | return 0; | |
736 | } | |
737 | ||
738 | static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, | |
739 | int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) | |
740 | { | |
741 | /* Perform I/O through a temporary buffer so that users who scribble over | |
742 | * their read buffer while the operation is in progress do not end up | |
743 | * modifying the image file. This is critical for zero-copy guest I/O | |
744 | * where anything might happen inside guest memory. | |
745 | */ | |
746 | void *bounce_buffer; | |
747 | ||
748 | BlockDriver *drv = bs->drv; | |
749 | struct iovec iov; | |
750 | QEMUIOVector bounce_qiov; | |
751 | int64_t cluster_sector_num; | |
752 | int cluster_nb_sectors; | |
753 | size_t skip_bytes; | |
754 | int ret; | |
755 | ||
756 | /* Cover entire cluster so no additional backing file I/O is required when | |
757 | * allocating cluster in the image file. | |
758 | */ | |
759 | bdrv_round_to_clusters(bs, sector_num, nb_sectors, | |
760 | &cluster_sector_num, &cluster_nb_sectors); | |
761 | ||
762 | trace_bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, | |
763 | cluster_sector_num, cluster_nb_sectors); | |
764 | ||
765 | iov.iov_len = cluster_nb_sectors * BDRV_SECTOR_SIZE; | |
766 | iov.iov_base = bounce_buffer = qemu_try_blockalign(bs, iov.iov_len); | |
767 | if (bounce_buffer == NULL) { | |
768 | ret = -ENOMEM; | |
769 | goto err; | |
770 | } | |
771 | ||
772 | qemu_iovec_init_external(&bounce_qiov, &iov, 1); | |
773 | ||
774 | ret = drv->bdrv_co_readv(bs, cluster_sector_num, cluster_nb_sectors, | |
775 | &bounce_qiov); | |
776 | if (ret < 0) { | |
777 | goto err; | |
778 | } | |
779 | ||
780 | if (drv->bdrv_co_write_zeroes && | |
781 | buffer_is_zero(bounce_buffer, iov.iov_len)) { | |
782 | ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num, | |
783 | cluster_nb_sectors, 0); | |
784 | } else { | |
785 | /* This does not change the data on the disk, it is not necessary | |
786 | * to flush even in cache=writethrough mode. | |
787 | */ | |
788 | ret = drv->bdrv_co_writev(bs, cluster_sector_num, cluster_nb_sectors, | |
789 | &bounce_qiov); | |
790 | } | |
791 | ||
792 | if (ret < 0) { | |
793 | /* It might be okay to ignore write errors for guest requests. If this | |
794 | * is a deliberate copy-on-read then we don't want to ignore the error. | |
795 | * Simply report it in all cases. | |
796 | */ | |
797 | goto err; | |
798 | } | |
799 | ||
800 | skip_bytes = (sector_num - cluster_sector_num) * BDRV_SECTOR_SIZE; | |
801 | qemu_iovec_from_buf(qiov, 0, bounce_buffer + skip_bytes, | |
802 | nb_sectors * BDRV_SECTOR_SIZE); | |
803 | ||
804 | err: | |
805 | qemu_vfree(bounce_buffer); | |
806 | return ret; | |
807 | } | |
808 | ||
809 | /* | |
810 | * Forwards an already correctly aligned request to the BlockDriver. This | |
811 | * handles copy on read and zeroing after EOF; any other features must be | |
812 | * implemented by the caller. | |
813 | */ | |
814 | static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs, | |
815 | BdrvTrackedRequest *req, int64_t offset, unsigned int bytes, | |
816 | int64_t align, QEMUIOVector *qiov, int flags) | |
817 | { | |
818 | BlockDriver *drv = bs->drv; | |
819 | int ret; | |
820 | ||
821 | int64_t sector_num = offset >> BDRV_SECTOR_BITS; | |
822 | unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS; | |
823 | ||
824 | assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); | |
825 | assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); | |
826 | assert(!qiov || bytes == qiov->size); | |
827 | ||
828 | /* Handle Copy on Read and associated serialisation */ | |
829 | if (flags & BDRV_REQ_COPY_ON_READ) { | |
830 | /* If we touch the same cluster it counts as an overlap. This | |
831 | * guarantees that allocating writes will be serialized and not race | |
832 | * with each other for the same cluster. For example, in copy-on-read | |
833 | * it ensures that the CoR read and write operations are atomic and | |
834 | * guest writes cannot interleave between them. */ | |
835 | mark_request_serialising(req, bdrv_get_cluster_size(bs)); | |
836 | } | |
837 | ||
838 | wait_serialising_requests(req); | |
839 | ||
840 | if (flags & BDRV_REQ_COPY_ON_READ) { | |
841 | int pnum; | |
842 | ||
843 | ret = bdrv_is_allocated(bs, sector_num, nb_sectors, &pnum); | |
844 | if (ret < 0) { | |
845 | goto out; | |
846 | } | |
847 | ||
848 | if (!ret || pnum != nb_sectors) { | |
849 | ret = bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, qiov); | |
850 | goto out; | |
851 | } | |
852 | } | |
853 | ||
854 | /* Forward the request to the BlockDriver */ | |
855 | if (!bs->zero_beyond_eof) { | |
856 | ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); | |
857 | } else { | |
858 | /* Read zeros after EOF */ | |
859 | int64_t total_sectors, max_nb_sectors; | |
860 | ||
861 | total_sectors = bdrv_nb_sectors(bs); | |
862 | if (total_sectors < 0) { | |
863 | ret = total_sectors; | |
864 | goto out; | |
865 | } | |
866 | ||
867 | max_nb_sectors = ROUND_UP(MAX(0, total_sectors - sector_num), | |
868 | align >> BDRV_SECTOR_BITS); | |
869 | if (nb_sectors < max_nb_sectors) { | |
870 | ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); | |
871 | } else if (max_nb_sectors > 0) { | |
872 | QEMUIOVector local_qiov; | |
873 | ||
874 | qemu_iovec_init(&local_qiov, qiov->niov); | |
875 | qemu_iovec_concat(&local_qiov, qiov, 0, | |
876 | max_nb_sectors * BDRV_SECTOR_SIZE); | |
877 | ||
878 | ret = drv->bdrv_co_readv(bs, sector_num, max_nb_sectors, | |
879 | &local_qiov); | |
880 | ||
881 | qemu_iovec_destroy(&local_qiov); | |
882 | } else { | |
883 | ret = 0; | |
884 | } | |
885 | ||
886 | /* Reading beyond end of file is supposed to produce zeroes */ | |
887 | if (ret == 0 && total_sectors < sector_num + nb_sectors) { | |
888 | uint64_t offset = MAX(0, total_sectors - sector_num); | |
889 | uint64_t bytes = (sector_num + nb_sectors - offset) * | |
890 | BDRV_SECTOR_SIZE; | |
891 | qemu_iovec_memset(qiov, offset * BDRV_SECTOR_SIZE, 0, bytes); | |
892 | } | |
893 | } | |
894 | ||
895 | out: | |
896 | return ret; | |
897 | } | |
898 | ||
61007b31 SH |
899 | /* |
900 | * Handle a read request in coroutine context | |
901 | */ | |
902 | static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs, | |
903 | int64_t offset, unsigned int bytes, QEMUIOVector *qiov, | |
904 | BdrvRequestFlags flags) | |
905 | { | |
906 | BlockDriver *drv = bs->drv; | |
907 | BdrvTrackedRequest req; | |
908 | ||
d01c07f2 FZ |
909 | /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */ |
910 | uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment); | |
61007b31 SH |
911 | uint8_t *head_buf = NULL; |
912 | uint8_t *tail_buf = NULL; | |
913 | QEMUIOVector local_qiov; | |
914 | bool use_local_qiov = false; | |
915 | int ret; | |
916 | ||
917 | if (!drv) { | |
918 | return -ENOMEDIUM; | |
919 | } | |
920 | ||
921 | ret = bdrv_check_byte_request(bs, offset, bytes); | |
922 | if (ret < 0) { | |
923 | return ret; | |
924 | } | |
925 | ||
926 | if (bs->copy_on_read) { | |
927 | flags |= BDRV_REQ_COPY_ON_READ; | |
928 | } | |
929 | ||
930 | /* throttling disk I/O */ | |
931 | if (bs->io_limits_enabled) { | |
76f4afb4 | 932 | throttle_group_co_io_limits_intercept(bs, bytes, false); |
61007b31 SH |
933 | } |
934 | ||
935 | /* Align read if necessary by padding qiov */ | |
936 | if (offset & (align - 1)) { | |
937 | head_buf = qemu_blockalign(bs, align); | |
938 | qemu_iovec_init(&local_qiov, qiov->niov + 2); | |
939 | qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1)); | |
940 | qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); | |
941 | use_local_qiov = true; | |
942 | ||
943 | bytes += offset & (align - 1); | |
944 | offset = offset & ~(align - 1); | |
945 | } | |
946 | ||
947 | if ((offset + bytes) & (align - 1)) { | |
948 | if (!use_local_qiov) { | |
949 | qemu_iovec_init(&local_qiov, qiov->niov + 1); | |
950 | qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); | |
951 | use_local_qiov = true; | |
952 | } | |
953 | tail_buf = qemu_blockalign(bs, align); | |
954 | qemu_iovec_add(&local_qiov, tail_buf, | |
955 | align - ((offset + bytes) & (align - 1))); | |
956 | ||
957 | bytes = ROUND_UP(bytes, align); | |
958 | } | |
959 | ||
960 | tracked_request_begin(&req, bs, offset, bytes, false); | |
961 | ret = bdrv_aligned_preadv(bs, &req, offset, bytes, align, | |
962 | use_local_qiov ? &local_qiov : qiov, | |
963 | flags); | |
964 | tracked_request_end(&req); | |
965 | ||
966 | if (use_local_qiov) { | |
967 | qemu_iovec_destroy(&local_qiov); | |
968 | qemu_vfree(head_buf); | |
969 | qemu_vfree(tail_buf); | |
970 | } | |
971 | ||
972 | return ret; | |
973 | } | |
974 | ||
975 | static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, | |
976 | int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, | |
977 | BdrvRequestFlags flags) | |
978 | { | |
979 | if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) { | |
980 | return -EINVAL; | |
981 | } | |
982 | ||
983 | return bdrv_co_do_preadv(bs, sector_num << BDRV_SECTOR_BITS, | |
984 | nb_sectors << BDRV_SECTOR_BITS, qiov, flags); | |
985 | } | |
986 | ||
987 | int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num, | |
988 | int nb_sectors, QEMUIOVector *qiov) | |
989 | { | |
990 | trace_bdrv_co_readv(bs, sector_num, nb_sectors); | |
991 | ||
992 | return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 0); | |
993 | } | |
994 | ||
995 | int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs, | |
996 | int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) | |
997 | { | |
998 | trace_bdrv_co_copy_on_readv(bs, sector_num, nb_sectors); | |
999 | ||
1000 | return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, | |
1001 | BDRV_REQ_COPY_ON_READ); | |
1002 | } | |
1003 | ||
1004 | #define MAX_WRITE_ZEROES_BOUNCE_BUFFER 32768 | |
1005 | ||
1006 | static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs, | |
1007 | int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) | |
1008 | { | |
1009 | BlockDriver *drv = bs->drv; | |
1010 | QEMUIOVector qiov; | |
1011 | struct iovec iov = {0}; | |
1012 | int ret = 0; | |
1013 | ||
1014 | int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_write_zeroes, | |
1015 | BDRV_REQUEST_MAX_SECTORS); | |
1016 | ||
1017 | while (nb_sectors > 0 && !ret) { | |
1018 | int num = nb_sectors; | |
1019 | ||
1020 | /* Align request. Block drivers can expect the "bulk" of the request | |
1021 | * to be aligned. | |
1022 | */ | |
1023 | if (bs->bl.write_zeroes_alignment | |
1024 | && num > bs->bl.write_zeroes_alignment) { | |
1025 | if (sector_num % bs->bl.write_zeroes_alignment != 0) { | |
1026 | /* Make a small request up to the first aligned sector. */ | |
1027 | num = bs->bl.write_zeroes_alignment; | |
1028 | num -= sector_num % bs->bl.write_zeroes_alignment; | |
1029 | } else if ((sector_num + num) % bs->bl.write_zeroes_alignment != 0) { | |
1030 | /* Shorten the request to the last aligned sector. num cannot | |
1031 | * underflow because num > bs->bl.write_zeroes_alignment. | |
1032 | */ | |
1033 | num -= (sector_num + num) % bs->bl.write_zeroes_alignment; | |
1034 | } | |
1035 | } | |
1036 | ||
1037 | /* limit request size */ | |
1038 | if (num > max_write_zeroes) { | |
1039 | num = max_write_zeroes; | |
1040 | } | |
1041 | ||
1042 | ret = -ENOTSUP; | |
1043 | /* First try the efficient write zeroes operation */ | |
1044 | if (drv->bdrv_co_write_zeroes) { | |
1045 | ret = drv->bdrv_co_write_zeroes(bs, sector_num, num, flags); | |
1046 | } | |
1047 | ||
1048 | if (ret == -ENOTSUP) { | |
1049 | /* Fall back to bounce buffer if write zeroes is unsupported */ | |
1050 | int max_xfer_len = MIN_NON_ZERO(bs->bl.max_transfer_length, | |
1051 | MAX_WRITE_ZEROES_BOUNCE_BUFFER); | |
1052 | num = MIN(num, max_xfer_len); | |
1053 | iov.iov_len = num * BDRV_SECTOR_SIZE; | |
1054 | if (iov.iov_base == NULL) { | |
1055 | iov.iov_base = qemu_try_blockalign(bs, num * BDRV_SECTOR_SIZE); | |
1056 | if (iov.iov_base == NULL) { | |
1057 | ret = -ENOMEM; | |
1058 | goto fail; | |
1059 | } | |
1060 | memset(iov.iov_base, 0, num * BDRV_SECTOR_SIZE); | |
1061 | } | |
1062 | qemu_iovec_init_external(&qiov, &iov, 1); | |
1063 | ||
1064 | ret = drv->bdrv_co_writev(bs, sector_num, num, &qiov); | |
1065 | ||
1066 | /* Keep bounce buffer around if it is big enough for all | |
1067 | * all future requests. | |
1068 | */ | |
1069 | if (num < max_xfer_len) { | |
1070 | qemu_vfree(iov.iov_base); | |
1071 | iov.iov_base = NULL; | |
1072 | } | |
1073 | } | |
1074 | ||
1075 | sector_num += num; | |
1076 | nb_sectors -= num; | |
1077 | } | |
1078 | ||
1079 | fail: | |
1080 | qemu_vfree(iov.iov_base); | |
1081 | return ret; | |
1082 | } | |
1083 | ||
1084 | /* | |
1085 | * Forwards an already correctly aligned write request to the BlockDriver. | |
1086 | */ | |
1087 | static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs, | |
1088 | BdrvTrackedRequest *req, int64_t offset, unsigned int bytes, | |
1089 | QEMUIOVector *qiov, int flags) | |
1090 | { | |
1091 | BlockDriver *drv = bs->drv; | |
1092 | bool waited; | |
1093 | int ret; | |
1094 | ||
1095 | int64_t sector_num = offset >> BDRV_SECTOR_BITS; | |
1096 | unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS; | |
1097 | ||
1098 | assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); | |
1099 | assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); | |
1100 | assert(!qiov || bytes == qiov->size); | |
1101 | ||
1102 | waited = wait_serialising_requests(req); | |
1103 | assert(!waited || !req->serialising); | |
1104 | assert(req->overlap_offset <= offset); | |
1105 | assert(offset + bytes <= req->overlap_offset + req->overlap_bytes); | |
1106 | ||
1107 | ret = notifier_with_return_list_notify(&bs->before_write_notifiers, req); | |
1108 | ||
1109 | if (!ret && bs->detect_zeroes != BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF && | |
1110 | !(flags & BDRV_REQ_ZERO_WRITE) && drv->bdrv_co_write_zeroes && | |
1111 | qemu_iovec_is_zero(qiov)) { | |
1112 | flags |= BDRV_REQ_ZERO_WRITE; | |
1113 | if (bs->detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP) { | |
1114 | flags |= BDRV_REQ_MAY_UNMAP; | |
1115 | } | |
1116 | } | |
1117 | ||
1118 | if (ret < 0) { | |
1119 | /* Do nothing, write notifier decided to fail this request */ | |
1120 | } else if (flags & BDRV_REQ_ZERO_WRITE) { | |
1121 | BLKDBG_EVENT(bs, BLKDBG_PWRITEV_ZERO); | |
1122 | ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags); | |
1123 | } else { | |
1124 | BLKDBG_EVENT(bs, BLKDBG_PWRITEV); | |
1125 | ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov); | |
1126 | } | |
1127 | BLKDBG_EVENT(bs, BLKDBG_PWRITEV_DONE); | |
1128 | ||
1129 | if (ret == 0 && !bs->enable_write_cache) { | |
1130 | ret = bdrv_co_flush(bs); | |
1131 | } | |
1132 | ||
1133 | bdrv_set_dirty(bs, sector_num, nb_sectors); | |
1134 | ||
1135 | block_acct_highest_sector(&bs->stats, sector_num, nb_sectors); | |
1136 | ||
1137 | if (ret >= 0) { | |
1138 | bs->total_sectors = MAX(bs->total_sectors, sector_num + nb_sectors); | |
1139 | } | |
1140 | ||
1141 | return ret; | |
1142 | } | |
1143 | ||
9eeb6dd1 FZ |
1144 | static int coroutine_fn bdrv_co_do_zero_pwritev(BlockDriverState *bs, |
1145 | int64_t offset, | |
1146 | unsigned int bytes, | |
1147 | BdrvRequestFlags flags, | |
1148 | BdrvTrackedRequest *req) | |
1149 | { | |
1150 | uint8_t *buf = NULL; | |
1151 | QEMUIOVector local_qiov; | |
1152 | struct iovec iov; | |
1153 | uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment); | |
1154 | unsigned int head_padding_bytes, tail_padding_bytes; | |
1155 | int ret = 0; | |
1156 | ||
1157 | head_padding_bytes = offset & (align - 1); | |
1158 | tail_padding_bytes = align - ((offset + bytes) & (align - 1)); | |
1159 | ||
1160 | ||
1161 | assert(flags & BDRV_REQ_ZERO_WRITE); | |
1162 | if (head_padding_bytes || tail_padding_bytes) { | |
1163 | buf = qemu_blockalign(bs, align); | |
1164 | iov = (struct iovec) { | |
1165 | .iov_base = buf, | |
1166 | .iov_len = align, | |
1167 | }; | |
1168 | qemu_iovec_init_external(&local_qiov, &iov, 1); | |
1169 | } | |
1170 | if (head_padding_bytes) { | |
1171 | uint64_t zero_bytes = MIN(bytes, align - head_padding_bytes); | |
1172 | ||
1173 | /* RMW the unaligned part before head. */ | |
1174 | mark_request_serialising(req, align); | |
1175 | wait_serialising_requests(req); | |
1176 | BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_HEAD); | |
1177 | ret = bdrv_aligned_preadv(bs, req, offset & ~(align - 1), align, | |
1178 | align, &local_qiov, 0); | |
1179 | if (ret < 0) { | |
1180 | goto fail; | |
1181 | } | |
1182 | BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD); | |
1183 | ||
1184 | memset(buf + head_padding_bytes, 0, zero_bytes); | |
1185 | ret = bdrv_aligned_pwritev(bs, req, offset & ~(align - 1), align, | |
1186 | &local_qiov, | |
1187 | flags & ~BDRV_REQ_ZERO_WRITE); | |
1188 | if (ret < 0) { | |
1189 | goto fail; | |
1190 | } | |
1191 | offset += zero_bytes; | |
1192 | bytes -= zero_bytes; | |
1193 | } | |
1194 | ||
1195 | assert(!bytes || (offset & (align - 1)) == 0); | |
1196 | if (bytes >= align) { | |
1197 | /* Write the aligned part in the middle. */ | |
1198 | uint64_t aligned_bytes = bytes & ~(align - 1); | |
1199 | ret = bdrv_aligned_pwritev(bs, req, offset, aligned_bytes, | |
1200 | NULL, flags); | |
1201 | if (ret < 0) { | |
1202 | goto fail; | |
1203 | } | |
1204 | bytes -= aligned_bytes; | |
1205 | offset += aligned_bytes; | |
1206 | } | |
1207 | ||
1208 | assert(!bytes || (offset & (align - 1)) == 0); | |
1209 | if (bytes) { | |
1210 | assert(align == tail_padding_bytes + bytes); | |
1211 | /* RMW the unaligned part after tail. */ | |
1212 | mark_request_serialising(req, align); | |
1213 | wait_serialising_requests(req); | |
1214 | BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_TAIL); | |
1215 | ret = bdrv_aligned_preadv(bs, req, offset, align, | |
1216 | align, &local_qiov, 0); | |
1217 | if (ret < 0) { | |
1218 | goto fail; | |
1219 | } | |
1220 | BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL); | |
1221 | ||
1222 | memset(buf, 0, bytes); | |
1223 | ret = bdrv_aligned_pwritev(bs, req, offset, align, | |
1224 | &local_qiov, flags & ~BDRV_REQ_ZERO_WRITE); | |
1225 | } | |
1226 | fail: | |
1227 | qemu_vfree(buf); | |
1228 | return ret; | |
1229 | ||
1230 | } | |
1231 | ||
61007b31 SH |
1232 | /* |
1233 | * Handle a write request in coroutine context | |
1234 | */ | |
1235 | static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs, | |
1236 | int64_t offset, unsigned int bytes, QEMUIOVector *qiov, | |
1237 | BdrvRequestFlags flags) | |
1238 | { | |
1239 | BdrvTrackedRequest req; | |
d01c07f2 FZ |
1240 | /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */ |
1241 | uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment); | |
61007b31 SH |
1242 | uint8_t *head_buf = NULL; |
1243 | uint8_t *tail_buf = NULL; | |
1244 | QEMUIOVector local_qiov; | |
1245 | bool use_local_qiov = false; | |
1246 | int ret; | |
1247 | ||
1248 | if (!bs->drv) { | |
1249 | return -ENOMEDIUM; | |
1250 | } | |
1251 | if (bs->read_only) { | |
eaf5fe2d | 1252 | return -EPERM; |
61007b31 SH |
1253 | } |
1254 | ||
1255 | ret = bdrv_check_byte_request(bs, offset, bytes); | |
1256 | if (ret < 0) { | |
1257 | return ret; | |
1258 | } | |
1259 | ||
1260 | /* throttling disk I/O */ | |
1261 | if (bs->io_limits_enabled) { | |
76f4afb4 | 1262 | throttle_group_co_io_limits_intercept(bs, bytes, true); |
61007b31 SH |
1263 | } |
1264 | ||
1265 | /* | |
1266 | * Align write if necessary by performing a read-modify-write cycle. | |
1267 | * Pad qiov with the read parts and be sure to have a tracked request not | |
1268 | * only for bdrv_aligned_pwritev, but also for the reads of the RMW cycle. | |
1269 | */ | |
1270 | tracked_request_begin(&req, bs, offset, bytes, true); | |
1271 | ||
9eeb6dd1 FZ |
1272 | if (!qiov) { |
1273 | ret = bdrv_co_do_zero_pwritev(bs, offset, bytes, flags, &req); | |
1274 | goto out; | |
1275 | } | |
1276 | ||
61007b31 SH |
1277 | if (offset & (align - 1)) { |
1278 | QEMUIOVector head_qiov; | |
1279 | struct iovec head_iov; | |
1280 | ||
1281 | mark_request_serialising(&req, align); | |
1282 | wait_serialising_requests(&req); | |
1283 | ||
1284 | head_buf = qemu_blockalign(bs, align); | |
1285 | head_iov = (struct iovec) { | |
1286 | .iov_base = head_buf, | |
1287 | .iov_len = align, | |
1288 | }; | |
1289 | qemu_iovec_init_external(&head_qiov, &head_iov, 1); | |
1290 | ||
1291 | BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_HEAD); | |
1292 | ret = bdrv_aligned_preadv(bs, &req, offset & ~(align - 1), align, | |
1293 | align, &head_qiov, 0); | |
1294 | if (ret < 0) { | |
1295 | goto fail; | |
1296 | } | |
1297 | BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD); | |
1298 | ||
1299 | qemu_iovec_init(&local_qiov, qiov->niov + 2); | |
1300 | qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1)); | |
1301 | qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); | |
1302 | use_local_qiov = true; | |
1303 | ||
1304 | bytes += offset & (align - 1); | |
1305 | offset = offset & ~(align - 1); | |
1306 | } | |
1307 | ||
1308 | if ((offset + bytes) & (align - 1)) { | |
1309 | QEMUIOVector tail_qiov; | |
1310 | struct iovec tail_iov; | |
1311 | size_t tail_bytes; | |
1312 | bool waited; | |
1313 | ||
1314 | mark_request_serialising(&req, align); | |
1315 | waited = wait_serialising_requests(&req); | |
1316 | assert(!waited || !use_local_qiov); | |
1317 | ||
1318 | tail_buf = qemu_blockalign(bs, align); | |
1319 | tail_iov = (struct iovec) { | |
1320 | .iov_base = tail_buf, | |
1321 | .iov_len = align, | |
1322 | }; | |
1323 | qemu_iovec_init_external(&tail_qiov, &tail_iov, 1); | |
1324 | ||
1325 | BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_TAIL); | |
1326 | ret = bdrv_aligned_preadv(bs, &req, (offset + bytes) & ~(align - 1), align, | |
1327 | align, &tail_qiov, 0); | |
1328 | if (ret < 0) { | |
1329 | goto fail; | |
1330 | } | |
1331 | BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL); | |
1332 | ||
1333 | if (!use_local_qiov) { | |
1334 | qemu_iovec_init(&local_qiov, qiov->niov + 1); | |
1335 | qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); | |
1336 | use_local_qiov = true; | |
1337 | } | |
1338 | ||
1339 | tail_bytes = (offset + bytes) & (align - 1); | |
1340 | qemu_iovec_add(&local_qiov, tail_buf + tail_bytes, align - tail_bytes); | |
1341 | ||
1342 | bytes = ROUND_UP(bytes, align); | |
1343 | } | |
1344 | ||
61007b31 SH |
1345 | ret = bdrv_aligned_pwritev(bs, &req, offset, bytes, |
1346 | use_local_qiov ? &local_qiov : qiov, | |
1347 | flags); | |
1348 | ||
1349 | fail: | |
61007b31 SH |
1350 | |
1351 | if (use_local_qiov) { | |
1352 | qemu_iovec_destroy(&local_qiov); | |
1353 | } | |
1354 | qemu_vfree(head_buf); | |
1355 | qemu_vfree(tail_buf); | |
9eeb6dd1 FZ |
1356 | out: |
1357 | tracked_request_end(&req); | |
61007b31 SH |
1358 | return ret; |
1359 | } | |
1360 | ||
1361 | static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, | |
1362 | int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, | |
1363 | BdrvRequestFlags flags) | |
1364 | { | |
1365 | if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) { | |
1366 | return -EINVAL; | |
1367 | } | |
1368 | ||
1369 | return bdrv_co_do_pwritev(bs, sector_num << BDRV_SECTOR_BITS, | |
1370 | nb_sectors << BDRV_SECTOR_BITS, qiov, flags); | |
1371 | } | |
1372 | ||
1373 | int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num, | |
1374 | int nb_sectors, QEMUIOVector *qiov) | |
1375 | { | |
1376 | trace_bdrv_co_writev(bs, sector_num, nb_sectors); | |
1377 | ||
1378 | return bdrv_co_do_writev(bs, sector_num, nb_sectors, qiov, 0); | |
1379 | } | |
1380 | ||
1381 | int coroutine_fn bdrv_co_write_zeroes(BlockDriverState *bs, | |
1382 | int64_t sector_num, int nb_sectors, | |
1383 | BdrvRequestFlags flags) | |
1384 | { | |
61007b31 SH |
1385 | trace_bdrv_co_write_zeroes(bs, sector_num, nb_sectors, flags); |
1386 | ||
1387 | if (!(bs->open_flags & BDRV_O_UNMAP)) { | |
1388 | flags &= ~BDRV_REQ_MAY_UNMAP; | |
1389 | } | |
61007b31 | 1390 | |
d01c07f2 FZ |
1391 | return bdrv_co_do_writev(bs, sector_num, nb_sectors, NULL, |
1392 | BDRV_REQ_ZERO_WRITE | flags); | |
61007b31 SH |
1393 | } |
1394 | ||
1395 | int bdrv_flush_all(void) | |
1396 | { | |
1397 | BlockDriverState *bs = NULL; | |
1398 | int result = 0; | |
1399 | ||
1400 | while ((bs = bdrv_next(bs))) { | |
1401 | AioContext *aio_context = bdrv_get_aio_context(bs); | |
1402 | int ret; | |
1403 | ||
1404 | aio_context_acquire(aio_context); | |
1405 | ret = bdrv_flush(bs); | |
1406 | if (ret < 0 && !result) { | |
1407 | result = ret; | |
1408 | } | |
1409 | aio_context_release(aio_context); | |
1410 | } | |
1411 | ||
1412 | return result; | |
1413 | } | |
1414 | ||
1415 | typedef struct BdrvCoGetBlockStatusData { | |
1416 | BlockDriverState *bs; | |
1417 | BlockDriverState *base; | |
1418 | int64_t sector_num; | |
1419 | int nb_sectors; | |
1420 | int *pnum; | |
1421 | int64_t ret; | |
1422 | bool done; | |
1423 | } BdrvCoGetBlockStatusData; | |
1424 | ||
1425 | /* | |
1426 | * Returns the allocation status of the specified sectors. | |
1427 | * Drivers not implementing the functionality are assumed to not support | |
1428 | * backing files, hence all their sectors are reported as allocated. | |
1429 | * | |
1430 | * If 'sector_num' is beyond the end of the disk image the return value is 0 | |
1431 | * and 'pnum' is set to 0. | |
1432 | * | |
1433 | * 'pnum' is set to the number of sectors (including and immediately following | |
1434 | * the specified sector) that are known to be in the same | |
1435 | * allocated/unallocated state. | |
1436 | * | |
1437 | * 'nb_sectors' is the max value 'pnum' should be set to. If nb_sectors goes | |
1438 | * beyond the end of the disk image it will be clamped. | |
1439 | */ | |
1440 | static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, | |
1441 | int64_t sector_num, | |
1442 | int nb_sectors, int *pnum) | |
1443 | { | |
1444 | int64_t total_sectors; | |
1445 | int64_t n; | |
1446 | int64_t ret, ret2; | |
1447 | ||
1448 | total_sectors = bdrv_nb_sectors(bs); | |
1449 | if (total_sectors < 0) { | |
1450 | return total_sectors; | |
1451 | } | |
1452 | ||
1453 | if (sector_num >= total_sectors) { | |
1454 | *pnum = 0; | |
1455 | return 0; | |
1456 | } | |
1457 | ||
1458 | n = total_sectors - sector_num; | |
1459 | if (n < nb_sectors) { | |
1460 | nb_sectors = n; | |
1461 | } | |
1462 | ||
1463 | if (!bs->drv->bdrv_co_get_block_status) { | |
1464 | *pnum = nb_sectors; | |
1465 | ret = BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED; | |
1466 | if (bs->drv->protocol_name) { | |
1467 | ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE); | |
1468 | } | |
1469 | return ret; | |
1470 | } | |
1471 | ||
1472 | ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum); | |
1473 | if (ret < 0) { | |
1474 | *pnum = 0; | |
1475 | return ret; | |
1476 | } | |
1477 | ||
1478 | if (ret & BDRV_BLOCK_RAW) { | |
1479 | assert(ret & BDRV_BLOCK_OFFSET_VALID); | |
1480 | return bdrv_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS, | |
1481 | *pnum, pnum); | |
1482 | } | |
1483 | ||
1484 | if (ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ZERO)) { | |
1485 | ret |= BDRV_BLOCK_ALLOCATED; | |
a53f1a95 | 1486 | } else { |
61007b31 SH |
1487 | if (bdrv_unallocated_blocks_are_zero(bs)) { |
1488 | ret |= BDRV_BLOCK_ZERO; | |
1489 | } else if (bs->backing_hd) { | |
1490 | BlockDriverState *bs2 = bs->backing_hd; | |
1491 | int64_t nb_sectors2 = bdrv_nb_sectors(bs2); | |
1492 | if (nb_sectors2 >= 0 && sector_num >= nb_sectors2) { | |
1493 | ret |= BDRV_BLOCK_ZERO; | |
1494 | } | |
1495 | } | |
1496 | } | |
1497 | ||
1498 | if (bs->file && | |
1499 | (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) && | |
1500 | (ret & BDRV_BLOCK_OFFSET_VALID)) { | |
1501 | int file_pnum; | |
1502 | ||
1503 | ret2 = bdrv_co_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS, | |
1504 | *pnum, &file_pnum); | |
1505 | if (ret2 >= 0) { | |
1506 | /* Ignore errors. This is just providing extra information, it | |
1507 | * is useful but not necessary. | |
1508 | */ | |
1509 | if (!file_pnum) { | |
1510 | /* !file_pnum indicates an offset at or beyond the EOF; it is | |
1511 | * perfectly valid for the format block driver to point to such | |
1512 | * offsets, so catch it and mark everything as zero */ | |
1513 | ret |= BDRV_BLOCK_ZERO; | |
1514 | } else { | |
1515 | /* Limit request to the range reported by the protocol driver */ | |
1516 | *pnum = file_pnum; | |
1517 | ret |= (ret2 & BDRV_BLOCK_ZERO); | |
1518 | } | |
1519 | } | |
1520 | } | |
1521 | ||
1522 | return ret; | |
1523 | } | |
1524 | ||
1525 | /* Coroutine wrapper for bdrv_get_block_status() */ | |
1526 | static void coroutine_fn bdrv_get_block_status_co_entry(void *opaque) | |
1527 | { | |
1528 | BdrvCoGetBlockStatusData *data = opaque; | |
1529 | BlockDriverState *bs = data->bs; | |
1530 | ||
1531 | data->ret = bdrv_co_get_block_status(bs, data->sector_num, data->nb_sectors, | |
1532 | data->pnum); | |
1533 | data->done = true; | |
1534 | } | |
1535 | ||
1536 | /* | |
1537 | * Synchronous wrapper around bdrv_co_get_block_status(). | |
1538 | * | |
1539 | * See bdrv_co_get_block_status() for details. | |
1540 | */ | |
1541 | int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num, | |
1542 | int nb_sectors, int *pnum) | |
1543 | { | |
1544 | Coroutine *co; | |
1545 | BdrvCoGetBlockStatusData data = { | |
1546 | .bs = bs, | |
1547 | .sector_num = sector_num, | |
1548 | .nb_sectors = nb_sectors, | |
1549 | .pnum = pnum, | |
1550 | .done = false, | |
1551 | }; | |
1552 | ||
1553 | if (qemu_in_coroutine()) { | |
1554 | /* Fast-path if already in coroutine context */ | |
1555 | bdrv_get_block_status_co_entry(&data); | |
1556 | } else { | |
1557 | AioContext *aio_context = bdrv_get_aio_context(bs); | |
1558 | ||
1559 | co = qemu_coroutine_create(bdrv_get_block_status_co_entry); | |
1560 | qemu_coroutine_enter(co, &data); | |
1561 | while (!data.done) { | |
1562 | aio_poll(aio_context, true); | |
1563 | } | |
1564 | } | |
1565 | return data.ret; | |
1566 | } | |
1567 | ||
1568 | int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, | |
1569 | int nb_sectors, int *pnum) | |
1570 | { | |
1571 | int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum); | |
1572 | if (ret < 0) { | |
1573 | return ret; | |
1574 | } | |
1575 | return !!(ret & BDRV_BLOCK_ALLOCATED); | |
1576 | } | |
1577 | ||
1578 | /* | |
1579 | * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP] | |
1580 | * | |
1581 | * Return true if the given sector is allocated in any image between | |
1582 | * BASE and TOP (inclusive). BASE can be NULL to check if the given | |
1583 | * sector is allocated in any image of the chain. Return false otherwise. | |
1584 | * | |
1585 | * 'pnum' is set to the number of sectors (including and immediately following | |
1586 | * the specified sector) that are known to be in the same | |
1587 | * allocated/unallocated state. | |
1588 | * | |
1589 | */ | |
1590 | int bdrv_is_allocated_above(BlockDriverState *top, | |
1591 | BlockDriverState *base, | |
1592 | int64_t sector_num, | |
1593 | int nb_sectors, int *pnum) | |
1594 | { | |
1595 | BlockDriverState *intermediate; | |
1596 | int ret, n = nb_sectors; | |
1597 | ||
1598 | intermediate = top; | |
1599 | while (intermediate && intermediate != base) { | |
1600 | int pnum_inter; | |
1601 | ret = bdrv_is_allocated(intermediate, sector_num, nb_sectors, | |
1602 | &pnum_inter); | |
1603 | if (ret < 0) { | |
1604 | return ret; | |
1605 | } else if (ret) { | |
1606 | *pnum = pnum_inter; | |
1607 | return 1; | |
1608 | } | |
1609 | ||
1610 | /* | |
1611 | * [sector_num, nb_sectors] is unallocated on top but intermediate | |
1612 | * might have | |
1613 | * | |
1614 | * [sector_num+x, nr_sectors] allocated. | |
1615 | */ | |
1616 | if (n > pnum_inter && | |
1617 | (intermediate == top || | |
1618 | sector_num + pnum_inter < intermediate->total_sectors)) { | |
1619 | n = pnum_inter; | |
1620 | } | |
1621 | ||
1622 | intermediate = intermediate->backing_hd; | |
1623 | } | |
1624 | ||
1625 | *pnum = n; | |
1626 | return 0; | |
1627 | } | |
1628 | ||
1629 | int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num, | |
1630 | const uint8_t *buf, int nb_sectors) | |
1631 | { | |
1632 | BlockDriver *drv = bs->drv; | |
1633 | int ret; | |
1634 | ||
1635 | if (!drv) { | |
1636 | return -ENOMEDIUM; | |
1637 | } | |
1638 | if (!drv->bdrv_write_compressed) { | |
1639 | return -ENOTSUP; | |
1640 | } | |
1641 | ret = bdrv_check_request(bs, sector_num, nb_sectors); | |
1642 | if (ret < 0) { | |
1643 | return ret; | |
1644 | } | |
1645 | ||
1646 | assert(QLIST_EMPTY(&bs->dirty_bitmaps)); | |
1647 | ||
1648 | return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors); | |
1649 | } | |
1650 | ||
1651 | int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf, | |
1652 | int64_t pos, int size) | |
1653 | { | |
1654 | QEMUIOVector qiov; | |
1655 | struct iovec iov = { | |
1656 | .iov_base = (void *) buf, | |
1657 | .iov_len = size, | |
1658 | }; | |
1659 | ||
1660 | qemu_iovec_init_external(&qiov, &iov, 1); | |
1661 | return bdrv_writev_vmstate(bs, &qiov, pos); | |
1662 | } | |
1663 | ||
1664 | int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) | |
1665 | { | |
1666 | BlockDriver *drv = bs->drv; | |
1667 | ||
1668 | if (!drv) { | |
1669 | return -ENOMEDIUM; | |
1670 | } else if (drv->bdrv_save_vmstate) { | |
1671 | return drv->bdrv_save_vmstate(bs, qiov, pos); | |
1672 | } else if (bs->file) { | |
1673 | return bdrv_writev_vmstate(bs->file, qiov, pos); | |
1674 | } | |
1675 | ||
1676 | return -ENOTSUP; | |
1677 | } | |
1678 | ||
1679 | int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf, | |
1680 | int64_t pos, int size) | |
1681 | { | |
1682 | BlockDriver *drv = bs->drv; | |
1683 | if (!drv) | |
1684 | return -ENOMEDIUM; | |
1685 | if (drv->bdrv_load_vmstate) | |
1686 | return drv->bdrv_load_vmstate(bs, buf, pos, size); | |
1687 | if (bs->file) | |
1688 | return bdrv_load_vmstate(bs->file, buf, pos, size); | |
1689 | return -ENOTSUP; | |
1690 | } | |
1691 | ||
1692 | /**************************************************************/ | |
1693 | /* async I/Os */ | |
1694 | ||
1695 | BlockAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num, | |
1696 | QEMUIOVector *qiov, int nb_sectors, | |
1697 | BlockCompletionFunc *cb, void *opaque) | |
1698 | { | |
1699 | trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque); | |
1700 | ||
1701 | return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0, | |
1702 | cb, opaque, false); | |
1703 | } | |
1704 | ||
1705 | BlockAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, | |
1706 | QEMUIOVector *qiov, int nb_sectors, | |
1707 | BlockCompletionFunc *cb, void *opaque) | |
1708 | { | |
1709 | trace_bdrv_aio_writev(bs, sector_num, nb_sectors, opaque); | |
1710 | ||
1711 | return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0, | |
1712 | cb, opaque, true); | |
1713 | } | |
1714 | ||
1715 | BlockAIOCB *bdrv_aio_write_zeroes(BlockDriverState *bs, | |
1716 | int64_t sector_num, int nb_sectors, BdrvRequestFlags flags, | |
1717 | BlockCompletionFunc *cb, void *opaque) | |
1718 | { | |
1719 | trace_bdrv_aio_write_zeroes(bs, sector_num, nb_sectors, flags, opaque); | |
1720 | ||
1721 | return bdrv_co_aio_rw_vector(bs, sector_num, NULL, nb_sectors, | |
1722 | BDRV_REQ_ZERO_WRITE | flags, | |
1723 | cb, opaque, true); | |
1724 | } | |
1725 | ||
1726 | ||
1727 | typedef struct MultiwriteCB { | |
1728 | int error; | |
1729 | int num_requests; | |
1730 | int num_callbacks; | |
1731 | struct { | |
1732 | BlockCompletionFunc *cb; | |
1733 | void *opaque; | |
1734 | QEMUIOVector *free_qiov; | |
1735 | } callbacks[]; | |
1736 | } MultiwriteCB; | |
1737 | ||
1738 | static void multiwrite_user_cb(MultiwriteCB *mcb) | |
1739 | { | |
1740 | int i; | |
1741 | ||
1742 | for (i = 0; i < mcb->num_callbacks; i++) { | |
1743 | mcb->callbacks[i].cb(mcb->callbacks[i].opaque, mcb->error); | |
1744 | if (mcb->callbacks[i].free_qiov) { | |
1745 | qemu_iovec_destroy(mcb->callbacks[i].free_qiov); | |
1746 | } | |
1747 | g_free(mcb->callbacks[i].free_qiov); | |
1748 | } | |
1749 | } | |
1750 | ||
1751 | static void multiwrite_cb(void *opaque, int ret) | |
1752 | { | |
1753 | MultiwriteCB *mcb = opaque; | |
1754 | ||
1755 | trace_multiwrite_cb(mcb, ret); | |
1756 | ||
1757 | if (ret < 0 && !mcb->error) { | |
1758 | mcb->error = ret; | |
1759 | } | |
1760 | ||
1761 | mcb->num_requests--; | |
1762 | if (mcb->num_requests == 0) { | |
1763 | multiwrite_user_cb(mcb); | |
1764 | g_free(mcb); | |
1765 | } | |
1766 | } | |
1767 | ||
1768 | static int multiwrite_req_compare(const void *a, const void *b) | |
1769 | { | |
1770 | const BlockRequest *req1 = a, *req2 = b; | |
1771 | ||
1772 | /* | |
1773 | * Note that we can't simply subtract req2->sector from req1->sector | |
1774 | * here as that could overflow the return value. | |
1775 | */ | |
1776 | if (req1->sector > req2->sector) { | |
1777 | return 1; | |
1778 | } else if (req1->sector < req2->sector) { | |
1779 | return -1; | |
1780 | } else { | |
1781 | return 0; | |
1782 | } | |
1783 | } | |
1784 | ||
1785 | /* | |
1786 | * Takes a bunch of requests and tries to merge them. Returns the number of | |
1787 | * requests that remain after merging. | |
1788 | */ | |
1789 | static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs, | |
1790 | int num_reqs, MultiwriteCB *mcb) | |
1791 | { | |
1792 | int i, outidx; | |
1793 | ||
1794 | // Sort requests by start sector | |
1795 | qsort(reqs, num_reqs, sizeof(*reqs), &multiwrite_req_compare); | |
1796 | ||
1797 | // Check if adjacent requests touch the same clusters. If so, combine them, | |
1798 | // filling up gaps with zero sectors. | |
1799 | outidx = 0; | |
1800 | for (i = 1; i < num_reqs; i++) { | |
1801 | int merge = 0; | |
1802 | int64_t oldreq_last = reqs[outidx].sector + reqs[outidx].nb_sectors; | |
1803 | ||
1804 | // Handle exactly sequential writes and overlapping writes. | |
1805 | if (reqs[i].sector <= oldreq_last) { | |
1806 | merge = 1; | |
1807 | } | |
1808 | ||
1809 | if (reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1 > IOV_MAX) { | |
1810 | merge = 0; | |
1811 | } | |
1812 | ||
1813 | if (bs->bl.max_transfer_length && reqs[outidx].nb_sectors + | |
1814 | reqs[i].nb_sectors > bs->bl.max_transfer_length) { | |
1815 | merge = 0; | |
1816 | } | |
1817 | ||
1818 | if (merge) { | |
1819 | size_t size; | |
1820 | QEMUIOVector *qiov = g_malloc0(sizeof(*qiov)); | |
1821 | qemu_iovec_init(qiov, | |
1822 | reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1); | |
1823 | ||
1824 | // Add the first request to the merged one. If the requests are | |
1825 | // overlapping, drop the last sectors of the first request. | |
1826 | size = (reqs[i].sector - reqs[outidx].sector) << 9; | |
1827 | qemu_iovec_concat(qiov, reqs[outidx].qiov, 0, size); | |
1828 | ||
1829 | // We should need to add any zeros between the two requests | |
1830 | assert (reqs[i].sector <= oldreq_last); | |
1831 | ||
1832 | // Add the second request | |
1833 | qemu_iovec_concat(qiov, reqs[i].qiov, 0, reqs[i].qiov->size); | |
1834 | ||
1835 | // Add tail of first request, if necessary | |
1836 | if (qiov->size < reqs[outidx].qiov->size) { | |
1837 | qemu_iovec_concat(qiov, reqs[outidx].qiov, qiov->size, | |
1838 | reqs[outidx].qiov->size - qiov->size); | |
1839 | } | |
1840 | ||
1841 | reqs[outidx].nb_sectors = qiov->size >> 9; | |
1842 | reqs[outidx].qiov = qiov; | |
1843 | ||
1844 | mcb->callbacks[i].free_qiov = reqs[outidx].qiov; | |
1845 | } else { | |
1846 | outidx++; | |
1847 | reqs[outidx].sector = reqs[i].sector; | |
1848 | reqs[outidx].nb_sectors = reqs[i].nb_sectors; | |
1849 | reqs[outidx].qiov = reqs[i].qiov; | |
1850 | } | |
1851 | } | |
1852 | ||
1853 | block_acct_merge_done(&bs->stats, BLOCK_ACCT_WRITE, num_reqs - outidx - 1); | |
1854 | ||
1855 | return outidx + 1; | |
1856 | } | |
1857 | ||
1858 | /* | |
1859 | * Submit multiple AIO write requests at once. | |
1860 | * | |
1861 | * On success, the function returns 0 and all requests in the reqs array have | |
1862 | * been submitted. In error case this function returns -1, and any of the | |
1863 | * requests may or may not be submitted yet. In particular, this means that the | |
1864 | * callback will be called for some of the requests, for others it won't. The | |
1865 | * caller must check the error field of the BlockRequest to wait for the right | |
1866 | * callbacks (if error != 0, no callback will be called). | |
1867 | * | |
1868 | * The implementation may modify the contents of the reqs array, e.g. to merge | |
1869 | * requests. However, the fields opaque and error are left unmodified as they | |
1870 | * are used to signal failure for a single request to the caller. | |
1871 | */ | |
1872 | int bdrv_aio_multiwrite(BlockDriverState *bs, BlockRequest *reqs, int num_reqs) | |
1873 | { | |
1874 | MultiwriteCB *mcb; | |
1875 | int i; | |
1876 | ||
1877 | /* don't submit writes if we don't have a medium */ | |
1878 | if (bs->drv == NULL) { | |
1879 | for (i = 0; i < num_reqs; i++) { | |
1880 | reqs[i].error = -ENOMEDIUM; | |
1881 | } | |
1882 | return -1; | |
1883 | } | |
1884 | ||
1885 | if (num_reqs == 0) { | |
1886 | return 0; | |
1887 | } | |
1888 | ||
1889 | // Create MultiwriteCB structure | |
1890 | mcb = g_malloc0(sizeof(*mcb) + num_reqs * sizeof(*mcb->callbacks)); | |
1891 | mcb->num_requests = 0; | |
1892 | mcb->num_callbacks = num_reqs; | |
1893 | ||
1894 | for (i = 0; i < num_reqs; i++) { | |
1895 | mcb->callbacks[i].cb = reqs[i].cb; | |
1896 | mcb->callbacks[i].opaque = reqs[i].opaque; | |
1897 | } | |
1898 | ||
1899 | // Check for mergable requests | |
1900 | num_reqs = multiwrite_merge(bs, reqs, num_reqs, mcb); | |
1901 | ||
1902 | trace_bdrv_aio_multiwrite(mcb, mcb->num_callbacks, num_reqs); | |
1903 | ||
1904 | /* Run the aio requests. */ | |
1905 | mcb->num_requests = num_reqs; | |
1906 | for (i = 0; i < num_reqs; i++) { | |
1907 | bdrv_co_aio_rw_vector(bs, reqs[i].sector, reqs[i].qiov, | |
1908 | reqs[i].nb_sectors, reqs[i].flags, | |
1909 | multiwrite_cb, mcb, | |
1910 | true); | |
1911 | } | |
1912 | ||
1913 | return 0; | |
1914 | } | |
1915 | ||
1916 | void bdrv_aio_cancel(BlockAIOCB *acb) | |
1917 | { | |
1918 | qemu_aio_ref(acb); | |
1919 | bdrv_aio_cancel_async(acb); | |
1920 | while (acb->refcnt > 1) { | |
1921 | if (acb->aiocb_info->get_aio_context) { | |
1922 | aio_poll(acb->aiocb_info->get_aio_context(acb), true); | |
1923 | } else if (acb->bs) { | |
1924 | aio_poll(bdrv_get_aio_context(acb->bs), true); | |
1925 | } else { | |
1926 | abort(); | |
1927 | } | |
1928 | } | |
1929 | qemu_aio_unref(acb); | |
1930 | } | |
1931 | ||
1932 | /* Async version of aio cancel. The caller is not blocked if the acb implements | |
1933 | * cancel_async, otherwise we do nothing and let the request normally complete. | |
1934 | * In either case the completion callback must be called. */ | |
1935 | void bdrv_aio_cancel_async(BlockAIOCB *acb) | |
1936 | { | |
1937 | if (acb->aiocb_info->cancel_async) { | |
1938 | acb->aiocb_info->cancel_async(acb); | |
1939 | } | |
1940 | } | |
1941 | ||
1942 | /**************************************************************/ | |
1943 | /* async block device emulation */ | |
1944 | ||
1945 | typedef struct BlockAIOCBSync { | |
1946 | BlockAIOCB common; | |
1947 | QEMUBH *bh; | |
1948 | int ret; | |
1949 | /* vector translation state */ | |
1950 | QEMUIOVector *qiov; | |
1951 | uint8_t *bounce; | |
1952 | int is_write; | |
1953 | } BlockAIOCBSync; | |
1954 | ||
1955 | static const AIOCBInfo bdrv_em_aiocb_info = { | |
1956 | .aiocb_size = sizeof(BlockAIOCBSync), | |
1957 | }; | |
1958 | ||
1959 | static void bdrv_aio_bh_cb(void *opaque) | |
1960 | { | |
1961 | BlockAIOCBSync *acb = opaque; | |
1962 | ||
1963 | if (!acb->is_write && acb->ret >= 0) { | |
1964 | qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size); | |
1965 | } | |
1966 | qemu_vfree(acb->bounce); | |
1967 | acb->common.cb(acb->common.opaque, acb->ret); | |
1968 | qemu_bh_delete(acb->bh); | |
1969 | acb->bh = NULL; | |
1970 | qemu_aio_unref(acb); | |
1971 | } | |
1972 | ||
1973 | static BlockAIOCB *bdrv_aio_rw_vector(BlockDriverState *bs, | |
1974 | int64_t sector_num, | |
1975 | QEMUIOVector *qiov, | |
1976 | int nb_sectors, | |
1977 | BlockCompletionFunc *cb, | |
1978 | void *opaque, | |
1979 | int is_write) | |
1980 | ||
1981 | { | |
1982 | BlockAIOCBSync *acb; | |
1983 | ||
1984 | acb = qemu_aio_get(&bdrv_em_aiocb_info, bs, cb, opaque); | |
1985 | acb->is_write = is_write; | |
1986 | acb->qiov = qiov; | |
1987 | acb->bounce = qemu_try_blockalign(bs, qiov->size); | |
1988 | acb->bh = aio_bh_new(bdrv_get_aio_context(bs), bdrv_aio_bh_cb, acb); | |
1989 | ||
1990 | if (acb->bounce == NULL) { | |
1991 | acb->ret = -ENOMEM; | |
1992 | } else if (is_write) { | |
1993 | qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size); | |
1994 | acb->ret = bs->drv->bdrv_write(bs, sector_num, acb->bounce, nb_sectors); | |
1995 | } else { | |
1996 | acb->ret = bs->drv->bdrv_read(bs, sector_num, acb->bounce, nb_sectors); | |
1997 | } | |
1998 | ||
1999 | qemu_bh_schedule(acb->bh); | |
2000 | ||
2001 | return &acb->common; | |
2002 | } | |
2003 | ||
2004 | static BlockAIOCB *bdrv_aio_readv_em(BlockDriverState *bs, | |
2005 | int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, | |
2006 | BlockCompletionFunc *cb, void *opaque) | |
2007 | { | |
2008 | return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); | |
2009 | } | |
2010 | ||
2011 | static BlockAIOCB *bdrv_aio_writev_em(BlockDriverState *bs, | |
2012 | int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, | |
2013 | BlockCompletionFunc *cb, void *opaque) | |
2014 | { | |
2015 | return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1); | |
2016 | } | |
2017 | ||
2018 | ||
2019 | typedef struct BlockAIOCBCoroutine { | |
2020 | BlockAIOCB common; | |
2021 | BlockRequest req; | |
2022 | bool is_write; | |
2023 | bool need_bh; | |
2024 | bool *done; | |
2025 | QEMUBH* bh; | |
2026 | } BlockAIOCBCoroutine; | |
2027 | ||
2028 | static const AIOCBInfo bdrv_em_co_aiocb_info = { | |
2029 | .aiocb_size = sizeof(BlockAIOCBCoroutine), | |
2030 | }; | |
2031 | ||
2032 | static void bdrv_co_complete(BlockAIOCBCoroutine *acb) | |
2033 | { | |
2034 | if (!acb->need_bh) { | |
2035 | acb->common.cb(acb->common.opaque, acb->req.error); | |
2036 | qemu_aio_unref(acb); | |
2037 | } | |
2038 | } | |
2039 | ||
2040 | static void bdrv_co_em_bh(void *opaque) | |
2041 | { | |
2042 | BlockAIOCBCoroutine *acb = opaque; | |
2043 | ||
2044 | assert(!acb->need_bh); | |
2045 | qemu_bh_delete(acb->bh); | |
2046 | bdrv_co_complete(acb); | |
2047 | } | |
2048 | ||
2049 | static void bdrv_co_maybe_schedule_bh(BlockAIOCBCoroutine *acb) | |
2050 | { | |
2051 | acb->need_bh = false; | |
2052 | if (acb->req.error != -EINPROGRESS) { | |
2053 | BlockDriverState *bs = acb->common.bs; | |
2054 | ||
2055 | acb->bh = aio_bh_new(bdrv_get_aio_context(bs), bdrv_co_em_bh, acb); | |
2056 | qemu_bh_schedule(acb->bh); | |
2057 | } | |
2058 | } | |
2059 | ||
2060 | /* Invoke bdrv_co_do_readv/bdrv_co_do_writev */ | |
2061 | static void coroutine_fn bdrv_co_do_rw(void *opaque) | |
2062 | { | |
2063 | BlockAIOCBCoroutine *acb = opaque; | |
2064 | BlockDriverState *bs = acb->common.bs; | |
2065 | ||
2066 | if (!acb->is_write) { | |
2067 | acb->req.error = bdrv_co_do_readv(bs, acb->req.sector, | |
2068 | acb->req.nb_sectors, acb->req.qiov, acb->req.flags); | |
2069 | } else { | |
2070 | acb->req.error = bdrv_co_do_writev(bs, acb->req.sector, | |
2071 | acb->req.nb_sectors, acb->req.qiov, acb->req.flags); | |
2072 | } | |
2073 | ||
2074 | bdrv_co_complete(acb); | |
2075 | } | |
2076 | ||
2077 | static BlockAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs, | |
2078 | int64_t sector_num, | |
2079 | QEMUIOVector *qiov, | |
2080 | int nb_sectors, | |
2081 | BdrvRequestFlags flags, | |
2082 | BlockCompletionFunc *cb, | |
2083 | void *opaque, | |
2084 | bool is_write) | |
2085 | { | |
2086 | Coroutine *co; | |
2087 | BlockAIOCBCoroutine *acb; | |
2088 | ||
2089 | acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); | |
2090 | acb->need_bh = true; | |
2091 | acb->req.error = -EINPROGRESS; | |
2092 | acb->req.sector = sector_num; | |
2093 | acb->req.nb_sectors = nb_sectors; | |
2094 | acb->req.qiov = qiov; | |
2095 | acb->req.flags = flags; | |
2096 | acb->is_write = is_write; | |
2097 | ||
2098 | co = qemu_coroutine_create(bdrv_co_do_rw); | |
2099 | qemu_coroutine_enter(co, acb); | |
2100 | ||
2101 | bdrv_co_maybe_schedule_bh(acb); | |
2102 | return &acb->common; | |
2103 | } | |
2104 | ||
2105 | static void coroutine_fn bdrv_aio_flush_co_entry(void *opaque) | |
2106 | { | |
2107 | BlockAIOCBCoroutine *acb = opaque; | |
2108 | BlockDriverState *bs = acb->common.bs; | |
2109 | ||
2110 | acb->req.error = bdrv_co_flush(bs); | |
2111 | bdrv_co_complete(acb); | |
2112 | } | |
2113 | ||
2114 | BlockAIOCB *bdrv_aio_flush(BlockDriverState *bs, | |
2115 | BlockCompletionFunc *cb, void *opaque) | |
2116 | { | |
2117 | trace_bdrv_aio_flush(bs, opaque); | |
2118 | ||
2119 | Coroutine *co; | |
2120 | BlockAIOCBCoroutine *acb; | |
2121 | ||
2122 | acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); | |
2123 | acb->need_bh = true; | |
2124 | acb->req.error = -EINPROGRESS; | |
2125 | ||
2126 | co = qemu_coroutine_create(bdrv_aio_flush_co_entry); | |
2127 | qemu_coroutine_enter(co, acb); | |
2128 | ||
2129 | bdrv_co_maybe_schedule_bh(acb); | |
2130 | return &acb->common; | |
2131 | } | |
2132 | ||
2133 | static void coroutine_fn bdrv_aio_discard_co_entry(void *opaque) | |
2134 | { | |
2135 | BlockAIOCBCoroutine *acb = opaque; | |
2136 | BlockDriverState *bs = acb->common.bs; | |
2137 | ||
2138 | acb->req.error = bdrv_co_discard(bs, acb->req.sector, acb->req.nb_sectors); | |
2139 | bdrv_co_complete(acb); | |
2140 | } | |
2141 | ||
2142 | BlockAIOCB *bdrv_aio_discard(BlockDriverState *bs, | |
2143 | int64_t sector_num, int nb_sectors, | |
2144 | BlockCompletionFunc *cb, void *opaque) | |
2145 | { | |
2146 | Coroutine *co; | |
2147 | BlockAIOCBCoroutine *acb; | |
2148 | ||
2149 | trace_bdrv_aio_discard(bs, sector_num, nb_sectors, opaque); | |
2150 | ||
2151 | acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); | |
2152 | acb->need_bh = true; | |
2153 | acb->req.error = -EINPROGRESS; | |
2154 | acb->req.sector = sector_num; | |
2155 | acb->req.nb_sectors = nb_sectors; | |
2156 | co = qemu_coroutine_create(bdrv_aio_discard_co_entry); | |
2157 | qemu_coroutine_enter(co, acb); | |
2158 | ||
2159 | bdrv_co_maybe_schedule_bh(acb); | |
2160 | return &acb->common; | |
2161 | } | |
2162 | ||
2163 | void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs, | |
2164 | BlockCompletionFunc *cb, void *opaque) | |
2165 | { | |
2166 | BlockAIOCB *acb; | |
2167 | ||
2168 | acb = g_slice_alloc(aiocb_info->aiocb_size); | |
2169 | acb->aiocb_info = aiocb_info; | |
2170 | acb->bs = bs; | |
2171 | acb->cb = cb; | |
2172 | acb->opaque = opaque; | |
2173 | acb->refcnt = 1; | |
2174 | return acb; | |
2175 | } | |
2176 | ||
2177 | void qemu_aio_ref(void *p) | |
2178 | { | |
2179 | BlockAIOCB *acb = p; | |
2180 | acb->refcnt++; | |
2181 | } | |
2182 | ||
2183 | void qemu_aio_unref(void *p) | |
2184 | { | |
2185 | BlockAIOCB *acb = p; | |
2186 | assert(acb->refcnt > 0); | |
2187 | if (--acb->refcnt == 0) { | |
2188 | g_slice_free1(acb->aiocb_info->aiocb_size, acb); | |
2189 | } | |
2190 | } | |
2191 | ||
2192 | /**************************************************************/ | |
2193 | /* Coroutine block device emulation */ | |
2194 | ||
2195 | typedef struct CoroutineIOCompletion { | |
2196 | Coroutine *coroutine; | |
2197 | int ret; | |
2198 | } CoroutineIOCompletion; | |
2199 | ||
2200 | static void bdrv_co_io_em_complete(void *opaque, int ret) | |
2201 | { | |
2202 | CoroutineIOCompletion *co = opaque; | |
2203 | ||
2204 | co->ret = ret; | |
2205 | qemu_coroutine_enter(co->coroutine, NULL); | |
2206 | } | |
2207 | ||
2208 | static int coroutine_fn bdrv_co_io_em(BlockDriverState *bs, int64_t sector_num, | |
2209 | int nb_sectors, QEMUIOVector *iov, | |
2210 | bool is_write) | |
2211 | { | |
2212 | CoroutineIOCompletion co = { | |
2213 | .coroutine = qemu_coroutine_self(), | |
2214 | }; | |
2215 | BlockAIOCB *acb; | |
2216 | ||
2217 | if (is_write) { | |
2218 | acb = bs->drv->bdrv_aio_writev(bs, sector_num, iov, nb_sectors, | |
2219 | bdrv_co_io_em_complete, &co); | |
2220 | } else { | |
2221 | acb = bs->drv->bdrv_aio_readv(bs, sector_num, iov, nb_sectors, | |
2222 | bdrv_co_io_em_complete, &co); | |
2223 | } | |
2224 | ||
2225 | trace_bdrv_co_io_em(bs, sector_num, nb_sectors, is_write, acb); | |
2226 | if (!acb) { | |
2227 | return -EIO; | |
2228 | } | |
2229 | qemu_coroutine_yield(); | |
2230 | ||
2231 | return co.ret; | |
2232 | } | |
2233 | ||
2234 | static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs, | |
2235 | int64_t sector_num, int nb_sectors, | |
2236 | QEMUIOVector *iov) | |
2237 | { | |
2238 | return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, false); | |
2239 | } | |
2240 | ||
2241 | static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, | |
2242 | int64_t sector_num, int nb_sectors, | |
2243 | QEMUIOVector *iov) | |
2244 | { | |
2245 | return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, true); | |
2246 | } | |
2247 | ||
2248 | static void coroutine_fn bdrv_flush_co_entry(void *opaque) | |
2249 | { | |
2250 | RwCo *rwco = opaque; | |
2251 | ||
2252 | rwco->ret = bdrv_co_flush(rwco->bs); | |
2253 | } | |
2254 | ||
2255 | int coroutine_fn bdrv_co_flush(BlockDriverState *bs) | |
2256 | { | |
2257 | int ret; | |
2258 | ||
2259 | if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) { | |
2260 | return 0; | |
2261 | } | |
2262 | ||
2263 | /* Write back cached data to the OS even with cache=unsafe */ | |
2264 | BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS); | |
2265 | if (bs->drv->bdrv_co_flush_to_os) { | |
2266 | ret = bs->drv->bdrv_co_flush_to_os(bs); | |
2267 | if (ret < 0) { | |
2268 | return ret; | |
2269 | } | |
2270 | } | |
2271 | ||
2272 | /* But don't actually force it to the disk with cache=unsafe */ | |
2273 | if (bs->open_flags & BDRV_O_NO_FLUSH) { | |
2274 | goto flush_parent; | |
2275 | } | |
2276 | ||
2277 | BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_DISK); | |
2278 | if (bs->drv->bdrv_co_flush_to_disk) { | |
2279 | ret = bs->drv->bdrv_co_flush_to_disk(bs); | |
2280 | } else if (bs->drv->bdrv_aio_flush) { | |
2281 | BlockAIOCB *acb; | |
2282 | CoroutineIOCompletion co = { | |
2283 | .coroutine = qemu_coroutine_self(), | |
2284 | }; | |
2285 | ||
2286 | acb = bs->drv->bdrv_aio_flush(bs, bdrv_co_io_em_complete, &co); | |
2287 | if (acb == NULL) { | |
2288 | ret = -EIO; | |
2289 | } else { | |
2290 | qemu_coroutine_yield(); | |
2291 | ret = co.ret; | |
2292 | } | |
2293 | } else { | |
2294 | /* | |
2295 | * Some block drivers always operate in either writethrough or unsafe | |
2296 | * mode and don't support bdrv_flush therefore. Usually qemu doesn't | |
2297 | * know how the server works (because the behaviour is hardcoded or | |
2298 | * depends on server-side configuration), so we can't ensure that | |
2299 | * everything is safe on disk. Returning an error doesn't work because | |
2300 | * that would break guests even if the server operates in writethrough | |
2301 | * mode. | |
2302 | * | |
2303 | * Let's hope the user knows what he's doing. | |
2304 | */ | |
2305 | ret = 0; | |
2306 | } | |
2307 | if (ret < 0) { | |
2308 | return ret; | |
2309 | } | |
2310 | ||
2311 | /* Now flush the underlying protocol. It will also have BDRV_O_NO_FLUSH | |
2312 | * in the case of cache=unsafe, so there are no useless flushes. | |
2313 | */ | |
2314 | flush_parent: | |
2315 | return bdrv_co_flush(bs->file); | |
2316 | } | |
2317 | ||
2318 | int bdrv_flush(BlockDriverState *bs) | |
2319 | { | |
2320 | Coroutine *co; | |
2321 | RwCo rwco = { | |
2322 | .bs = bs, | |
2323 | .ret = NOT_DONE, | |
2324 | }; | |
2325 | ||
2326 | if (qemu_in_coroutine()) { | |
2327 | /* Fast-path if already in coroutine context */ | |
2328 | bdrv_flush_co_entry(&rwco); | |
2329 | } else { | |
2330 | AioContext *aio_context = bdrv_get_aio_context(bs); | |
2331 | ||
2332 | co = qemu_coroutine_create(bdrv_flush_co_entry); | |
2333 | qemu_coroutine_enter(co, &rwco); | |
2334 | while (rwco.ret == NOT_DONE) { | |
2335 | aio_poll(aio_context, true); | |
2336 | } | |
2337 | } | |
2338 | ||
2339 | return rwco.ret; | |
2340 | } | |
2341 | ||
2342 | typedef struct DiscardCo { | |
2343 | BlockDriverState *bs; | |
2344 | int64_t sector_num; | |
2345 | int nb_sectors; | |
2346 | int ret; | |
2347 | } DiscardCo; | |
2348 | static void coroutine_fn bdrv_discard_co_entry(void *opaque) | |
2349 | { | |
2350 | DiscardCo *rwco = opaque; | |
2351 | ||
2352 | rwco->ret = bdrv_co_discard(rwco->bs, rwco->sector_num, rwco->nb_sectors); | |
2353 | } | |
2354 | ||
2355 | int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, | |
2356 | int nb_sectors) | |
2357 | { | |
2358 | int max_discard, ret; | |
2359 | ||
2360 | if (!bs->drv) { | |
2361 | return -ENOMEDIUM; | |
2362 | } | |
2363 | ||
2364 | ret = bdrv_check_request(bs, sector_num, nb_sectors); | |
2365 | if (ret < 0) { | |
2366 | return ret; | |
2367 | } else if (bs->read_only) { | |
eaf5fe2d | 2368 | return -EPERM; |
61007b31 SH |
2369 | } |
2370 | ||
2371 | bdrv_reset_dirty(bs, sector_num, nb_sectors); | |
2372 | ||
2373 | /* Do nothing if disabled. */ | |
2374 | if (!(bs->open_flags & BDRV_O_UNMAP)) { | |
2375 | return 0; | |
2376 | } | |
2377 | ||
2378 | if (!bs->drv->bdrv_co_discard && !bs->drv->bdrv_aio_discard) { | |
2379 | return 0; | |
2380 | } | |
2381 | ||
2382 | max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS); | |
2383 | while (nb_sectors > 0) { | |
2384 | int ret; | |
2385 | int num = nb_sectors; | |
2386 | ||
2387 | /* align request */ | |
2388 | if (bs->bl.discard_alignment && | |
2389 | num >= bs->bl.discard_alignment && | |
2390 | sector_num % bs->bl.discard_alignment) { | |
2391 | if (num > bs->bl.discard_alignment) { | |
2392 | num = bs->bl.discard_alignment; | |
2393 | } | |
2394 | num -= sector_num % bs->bl.discard_alignment; | |
2395 | } | |
2396 | ||
2397 | /* limit request size */ | |
2398 | if (num > max_discard) { | |
2399 | num = max_discard; | |
2400 | } | |
2401 | ||
2402 | if (bs->drv->bdrv_co_discard) { | |
2403 | ret = bs->drv->bdrv_co_discard(bs, sector_num, num); | |
2404 | } else { | |
2405 | BlockAIOCB *acb; | |
2406 | CoroutineIOCompletion co = { | |
2407 | .coroutine = qemu_coroutine_self(), | |
2408 | }; | |
2409 | ||
2410 | acb = bs->drv->bdrv_aio_discard(bs, sector_num, nb_sectors, | |
2411 | bdrv_co_io_em_complete, &co); | |
2412 | if (acb == NULL) { | |
2413 | return -EIO; | |
2414 | } else { | |
2415 | qemu_coroutine_yield(); | |
2416 | ret = co.ret; | |
2417 | } | |
2418 | } | |
2419 | if (ret && ret != -ENOTSUP) { | |
2420 | return ret; | |
2421 | } | |
2422 | ||
2423 | sector_num += num; | |
2424 | nb_sectors -= num; | |
2425 | } | |
2426 | return 0; | |
2427 | } | |
2428 | ||
2429 | int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors) | |
2430 | { | |
2431 | Coroutine *co; | |
2432 | DiscardCo rwco = { | |
2433 | .bs = bs, | |
2434 | .sector_num = sector_num, | |
2435 | .nb_sectors = nb_sectors, | |
2436 | .ret = NOT_DONE, | |
2437 | }; | |
2438 | ||
2439 | if (qemu_in_coroutine()) { | |
2440 | /* Fast-path if already in coroutine context */ | |
2441 | bdrv_discard_co_entry(&rwco); | |
2442 | } else { | |
2443 | AioContext *aio_context = bdrv_get_aio_context(bs); | |
2444 | ||
2445 | co = qemu_coroutine_create(bdrv_discard_co_entry); | |
2446 | qemu_coroutine_enter(co, &rwco); | |
2447 | while (rwco.ret == NOT_DONE) { | |
2448 | aio_poll(aio_context, true); | |
2449 | } | |
2450 | } | |
2451 | ||
2452 | return rwco.ret; | |
2453 | } | |
2454 | ||
2455 | /* needed for generic scsi interface */ | |
2456 | ||
2457 | int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf) | |
2458 | { | |
2459 | BlockDriver *drv = bs->drv; | |
2460 | ||
2461 | if (drv && drv->bdrv_ioctl) | |
2462 | return drv->bdrv_ioctl(bs, req, buf); | |
2463 | return -ENOTSUP; | |
2464 | } | |
2465 | ||
2466 | BlockAIOCB *bdrv_aio_ioctl(BlockDriverState *bs, | |
2467 | unsigned long int req, void *buf, | |
2468 | BlockCompletionFunc *cb, void *opaque) | |
2469 | { | |
2470 | BlockDriver *drv = bs->drv; | |
2471 | ||
2472 | if (drv && drv->bdrv_aio_ioctl) | |
2473 | return drv->bdrv_aio_ioctl(bs, req, buf, cb, opaque); | |
2474 | return NULL; | |
2475 | } | |
2476 | ||
2477 | void *qemu_blockalign(BlockDriverState *bs, size_t size) | |
2478 | { | |
2479 | return qemu_memalign(bdrv_opt_mem_align(bs), size); | |
2480 | } | |
2481 | ||
2482 | void *qemu_blockalign0(BlockDriverState *bs, size_t size) | |
2483 | { | |
2484 | return memset(qemu_blockalign(bs, size), 0, size); | |
2485 | } | |
2486 | ||
2487 | void *qemu_try_blockalign(BlockDriverState *bs, size_t size) | |
2488 | { | |
2489 | size_t align = bdrv_opt_mem_align(bs); | |
2490 | ||
2491 | /* Ensure that NULL is never returned on success */ | |
2492 | assert(align > 0); | |
2493 | if (size == 0) { | |
2494 | size = align; | |
2495 | } | |
2496 | ||
2497 | return qemu_try_memalign(align, size); | |
2498 | } | |
2499 | ||
2500 | void *qemu_try_blockalign0(BlockDriverState *bs, size_t size) | |
2501 | { | |
2502 | void *mem = qemu_try_blockalign(bs, size); | |
2503 | ||
2504 | if (mem) { | |
2505 | memset(mem, 0, size); | |
2506 | } | |
2507 | ||
2508 | return mem; | |
2509 | } | |
2510 | ||
2511 | /* | |
2512 | * Check if all memory in this vector is sector aligned. | |
2513 | */ | |
2514 | bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov) | |
2515 | { | |
2516 | int i; | |
4196d2f0 | 2517 | size_t alignment = bdrv_min_mem_align(bs); |
61007b31 SH |
2518 | |
2519 | for (i = 0; i < qiov->niov; i++) { | |
2520 | if ((uintptr_t) qiov->iov[i].iov_base % alignment) { | |
2521 | return false; | |
2522 | } | |
2523 | if (qiov->iov[i].iov_len % alignment) { | |
2524 | return false; | |
2525 | } | |
2526 | } | |
2527 | ||
2528 | return true; | |
2529 | } | |
2530 | ||
2531 | void bdrv_add_before_write_notifier(BlockDriverState *bs, | |
2532 | NotifierWithReturn *notifier) | |
2533 | { | |
2534 | notifier_with_return_list_add(&bs->before_write_notifiers, notifier); | |
2535 | } | |
2536 | ||
2537 | void bdrv_io_plug(BlockDriverState *bs) | |
2538 | { | |
2539 | BlockDriver *drv = bs->drv; | |
2540 | if (drv && drv->bdrv_io_plug) { | |
2541 | drv->bdrv_io_plug(bs); | |
2542 | } else if (bs->file) { | |
2543 | bdrv_io_plug(bs->file); | |
2544 | } | |
2545 | } | |
2546 | ||
2547 | void bdrv_io_unplug(BlockDriverState *bs) | |
2548 | { | |
2549 | BlockDriver *drv = bs->drv; | |
2550 | if (drv && drv->bdrv_io_unplug) { | |
2551 | drv->bdrv_io_unplug(bs); | |
2552 | } else if (bs->file) { | |
2553 | bdrv_io_unplug(bs->file); | |
2554 | } | |
2555 | } | |
2556 | ||
2557 | void bdrv_flush_io_queue(BlockDriverState *bs) | |
2558 | { | |
2559 | BlockDriver *drv = bs->drv; | |
2560 | if (drv && drv->bdrv_flush_io_queue) { | |
2561 | drv->bdrv_flush_io_queue(bs); | |
2562 | } else if (bs->file) { | |
2563 | bdrv_flush_io_queue(bs->file); | |
2564 | } | |
2565 | } |