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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 "qemu/osdep.h" | |
26 | #include "trace.h" | |
27 | #include "sysemu/block-backend.h" | |
28 | #include "block/aio-wait.h" | |
29 | #include "block/blockjob.h" | |
30 | #include "block/blockjob_int.h" | |
31 | #include "block/block_int.h" | |
32 | #include "block/coroutines.h" | |
33 | #include "block/dirty-bitmap.h" | |
34 | #include "block/write-threshold.h" | |
35 | #include "qemu/cutils.h" | |
36 | #include "qemu/memalign.h" | |
37 | #include "qapi/error.h" | |
38 | #include "qemu/error-report.h" | |
39 | #include "qemu/main-loop.h" | |
40 | #include "sysemu/replay.h" | |
41 | ||
42 | /* Maximum bounce buffer for copy-on-read and write zeroes, in bytes */ | |
43 | #define MAX_BOUNCE_BUFFER (32768 << BDRV_SECTOR_BITS) | |
44 | ||
45 | static void bdrv_parent_cb_resize(BlockDriverState *bs); | |
46 | static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, | |
47 | int64_t offset, int64_t bytes, BdrvRequestFlags flags); | |
48 | ||
49 | static void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore) | |
50 | { | |
51 | BdrvChild *c, *next; | |
52 | ||
53 | QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) { | |
54 | if (c == ignore) { | |
55 | continue; | |
56 | } | |
57 | bdrv_parent_drained_begin_single(c); | |
58 | } | |
59 | } | |
60 | ||
61 | void bdrv_parent_drained_end_single(BdrvChild *c) | |
62 | { | |
63 | GLOBAL_STATE_CODE(); | |
64 | ||
65 | assert(c->quiesced_parent); | |
66 | c->quiesced_parent = false; | |
67 | ||
68 | if (c->klass->drained_end) { | |
69 | c->klass->drained_end(c); | |
70 | } | |
71 | } | |
72 | ||
73 | static void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore) | |
74 | { | |
75 | BdrvChild *c; | |
76 | ||
77 | QLIST_FOREACH(c, &bs->parents, next_parent) { | |
78 | if (c == ignore) { | |
79 | continue; | |
80 | } | |
81 | bdrv_parent_drained_end_single(c); | |
82 | } | |
83 | } | |
84 | ||
85 | bool bdrv_parent_drained_poll_single(BdrvChild *c) | |
86 | { | |
87 | if (c->klass->drained_poll) { | |
88 | return c->klass->drained_poll(c); | |
89 | } | |
90 | return false; | |
91 | } | |
92 | ||
93 | static bool bdrv_parent_drained_poll(BlockDriverState *bs, BdrvChild *ignore, | |
94 | bool ignore_bds_parents) | |
95 | { | |
96 | BdrvChild *c, *next; | |
97 | bool busy = false; | |
98 | ||
99 | QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) { | |
100 | if (c == ignore || (ignore_bds_parents && c->klass->parent_is_bds)) { | |
101 | continue; | |
102 | } | |
103 | busy |= bdrv_parent_drained_poll_single(c); | |
104 | } | |
105 | ||
106 | return busy; | |
107 | } | |
108 | ||
109 | void bdrv_parent_drained_begin_single(BdrvChild *c) | |
110 | { | |
111 | GLOBAL_STATE_CODE(); | |
112 | ||
113 | assert(!c->quiesced_parent); | |
114 | c->quiesced_parent = true; | |
115 | ||
116 | if (c->klass->drained_begin) { | |
117 | c->klass->drained_begin(c); | |
118 | } | |
119 | } | |
120 | ||
121 | static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src) | |
122 | { | |
123 | dst->pdiscard_alignment = MAX(dst->pdiscard_alignment, | |
124 | src->pdiscard_alignment); | |
125 | dst->opt_transfer = MAX(dst->opt_transfer, src->opt_transfer); | |
126 | dst->max_transfer = MIN_NON_ZERO(dst->max_transfer, src->max_transfer); | |
127 | dst->max_hw_transfer = MIN_NON_ZERO(dst->max_hw_transfer, | |
128 | src->max_hw_transfer); | |
129 | dst->opt_mem_alignment = MAX(dst->opt_mem_alignment, | |
130 | src->opt_mem_alignment); | |
131 | dst->min_mem_alignment = MAX(dst->min_mem_alignment, | |
132 | src->min_mem_alignment); | |
133 | dst->max_iov = MIN_NON_ZERO(dst->max_iov, src->max_iov); | |
134 | dst->max_hw_iov = MIN_NON_ZERO(dst->max_hw_iov, src->max_hw_iov); | |
135 | } | |
136 | ||
137 | typedef struct BdrvRefreshLimitsState { | |
138 | BlockDriverState *bs; | |
139 | BlockLimits old_bl; | |
140 | } BdrvRefreshLimitsState; | |
141 | ||
142 | static void bdrv_refresh_limits_abort(void *opaque) | |
143 | { | |
144 | BdrvRefreshLimitsState *s = opaque; | |
145 | ||
146 | s->bs->bl = s->old_bl; | |
147 | } | |
148 | ||
149 | static TransactionActionDrv bdrv_refresh_limits_drv = { | |
150 | .abort = bdrv_refresh_limits_abort, | |
151 | .clean = g_free, | |
152 | }; | |
153 | ||
154 | /* @tran is allowed to be NULL, in this case no rollback is possible. */ | |
155 | void bdrv_refresh_limits(BlockDriverState *bs, Transaction *tran, Error **errp) | |
156 | { | |
157 | ERRP_GUARD(); | |
158 | BlockDriver *drv = bs->drv; | |
159 | BdrvChild *c; | |
160 | bool have_limits; | |
161 | ||
162 | GLOBAL_STATE_CODE(); | |
163 | ||
164 | if (tran) { | |
165 | BdrvRefreshLimitsState *s = g_new(BdrvRefreshLimitsState, 1); | |
166 | *s = (BdrvRefreshLimitsState) { | |
167 | .bs = bs, | |
168 | .old_bl = bs->bl, | |
169 | }; | |
170 | tran_add(tran, &bdrv_refresh_limits_drv, s); | |
171 | } | |
172 | ||
173 | memset(&bs->bl, 0, sizeof(bs->bl)); | |
174 | ||
175 | if (!drv) { | |
176 | return; | |
177 | } | |
178 | ||
179 | /* Default alignment based on whether driver has byte interface */ | |
180 | bs->bl.request_alignment = (drv->bdrv_co_preadv || | |
181 | drv->bdrv_aio_preadv || | |
182 | drv->bdrv_co_preadv_part) ? 1 : 512; | |
183 | ||
184 | /* Take some limits from the children as a default */ | |
185 | have_limits = false; | |
186 | QLIST_FOREACH(c, &bs->children, next) { | |
187 | if (c->role & (BDRV_CHILD_DATA | BDRV_CHILD_FILTERED | BDRV_CHILD_COW)) | |
188 | { | |
189 | bdrv_merge_limits(&bs->bl, &c->bs->bl); | |
190 | have_limits = true; | |
191 | } | |
192 | ||
193 | if (c->role & BDRV_CHILD_FILTERED) { | |
194 | bs->bl.has_variable_length |= c->bs->bl.has_variable_length; | |
195 | } | |
196 | } | |
197 | ||
198 | if (!have_limits) { | |
199 | bs->bl.min_mem_alignment = 512; | |
200 | bs->bl.opt_mem_alignment = qemu_real_host_page_size(); | |
201 | ||
202 | /* Safe default since most protocols use readv()/writev()/etc */ | |
203 | bs->bl.max_iov = IOV_MAX; | |
204 | } | |
205 | ||
206 | /* Then let the driver override it */ | |
207 | if (drv->bdrv_refresh_limits) { | |
208 | drv->bdrv_refresh_limits(bs, errp); | |
209 | if (*errp) { | |
210 | return; | |
211 | } | |
212 | } | |
213 | ||
214 | if (bs->bl.request_alignment > BDRV_MAX_ALIGNMENT) { | |
215 | error_setg(errp, "Driver requires too large request alignment"); | |
216 | } | |
217 | } | |
218 | ||
219 | /** | |
220 | * The copy-on-read flag is actually a reference count so multiple users may | |
221 | * use the feature without worrying about clobbering its previous state. | |
222 | * Copy-on-read stays enabled until all users have called to disable it. | |
223 | */ | |
224 | void bdrv_enable_copy_on_read(BlockDriverState *bs) | |
225 | { | |
226 | IO_CODE(); | |
227 | qatomic_inc(&bs->copy_on_read); | |
228 | } | |
229 | ||
230 | void bdrv_disable_copy_on_read(BlockDriverState *bs) | |
231 | { | |
232 | int old = qatomic_fetch_dec(&bs->copy_on_read); | |
233 | IO_CODE(); | |
234 | assert(old >= 1); | |
235 | } | |
236 | ||
237 | typedef struct { | |
238 | Coroutine *co; | |
239 | BlockDriverState *bs; | |
240 | bool done; | |
241 | bool begin; | |
242 | bool poll; | |
243 | BdrvChild *parent; | |
244 | } BdrvCoDrainData; | |
245 | ||
246 | /* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */ | |
247 | bool bdrv_drain_poll(BlockDriverState *bs, BdrvChild *ignore_parent, | |
248 | bool ignore_bds_parents) | |
249 | { | |
250 | GLOBAL_STATE_CODE(); | |
251 | ||
252 | if (bdrv_parent_drained_poll(bs, ignore_parent, ignore_bds_parents)) { | |
253 | return true; | |
254 | } | |
255 | ||
256 | if (qatomic_read(&bs->in_flight)) { | |
257 | return true; | |
258 | } | |
259 | ||
260 | return false; | |
261 | } | |
262 | ||
263 | static bool bdrv_drain_poll_top_level(BlockDriverState *bs, | |
264 | BdrvChild *ignore_parent) | |
265 | { | |
266 | return bdrv_drain_poll(bs, ignore_parent, false); | |
267 | } | |
268 | ||
269 | static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, | |
270 | bool poll); | |
271 | static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent); | |
272 | ||
273 | static void bdrv_co_drain_bh_cb(void *opaque) | |
274 | { | |
275 | BdrvCoDrainData *data = opaque; | |
276 | Coroutine *co = data->co; | |
277 | BlockDriverState *bs = data->bs; | |
278 | ||
279 | if (bs) { | |
280 | AioContext *ctx = bdrv_get_aio_context(bs); | |
281 | aio_context_acquire(ctx); | |
282 | bdrv_dec_in_flight(bs); | |
283 | if (data->begin) { | |
284 | bdrv_do_drained_begin(bs, data->parent, data->poll); | |
285 | } else { | |
286 | assert(!data->poll); | |
287 | bdrv_do_drained_end(bs, data->parent); | |
288 | } | |
289 | aio_context_release(ctx); | |
290 | } else { | |
291 | assert(data->begin); | |
292 | bdrv_drain_all_begin(); | |
293 | } | |
294 | ||
295 | data->done = true; | |
296 | aio_co_wake(co); | |
297 | } | |
298 | ||
299 | static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, | |
300 | bool begin, | |
301 | BdrvChild *parent, | |
302 | bool poll) | |
303 | { | |
304 | BdrvCoDrainData data; | |
305 | Coroutine *self = qemu_coroutine_self(); | |
306 | AioContext *ctx = bdrv_get_aio_context(bs); | |
307 | AioContext *co_ctx = qemu_coroutine_get_aio_context(self); | |
308 | ||
309 | /* Calling bdrv_drain() from a BH ensures the current coroutine yields and | |
310 | * other coroutines run if they were queued by aio_co_enter(). */ | |
311 | ||
312 | assert(qemu_in_coroutine()); | |
313 | data = (BdrvCoDrainData) { | |
314 | .co = self, | |
315 | .bs = bs, | |
316 | .done = false, | |
317 | .begin = begin, | |
318 | .parent = parent, | |
319 | .poll = poll, | |
320 | }; | |
321 | ||
322 | if (bs) { | |
323 | bdrv_inc_in_flight(bs); | |
324 | } | |
325 | ||
326 | /* | |
327 | * Temporarily drop the lock across yield or we would get deadlocks. | |
328 | * bdrv_co_drain_bh_cb() reaquires the lock as needed. | |
329 | * | |
330 | * When we yield below, the lock for the current context will be | |
331 | * released, so if this is actually the lock that protects bs, don't drop | |
332 | * it a second time. | |
333 | */ | |
334 | if (ctx != co_ctx) { | |
335 | aio_context_release(ctx); | |
336 | } | |
337 | replay_bh_schedule_oneshot_event(qemu_get_aio_context(), | |
338 | bdrv_co_drain_bh_cb, &data); | |
339 | ||
340 | qemu_coroutine_yield(); | |
341 | /* If we are resumed from some other event (such as an aio completion or a | |
342 | * timer callback), it is a bug in the caller that should be fixed. */ | |
343 | assert(data.done); | |
344 | ||
345 | /* Reacquire the AioContext of bs if we dropped it */ | |
346 | if (ctx != co_ctx) { | |
347 | aio_context_acquire(ctx); | |
348 | } | |
349 | } | |
350 | ||
351 | static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, | |
352 | bool poll) | |
353 | { | |
354 | IO_OR_GS_CODE(); | |
355 | ||
356 | if (qemu_in_coroutine()) { | |
357 | bdrv_co_yield_to_drain(bs, true, parent, poll); | |
358 | return; | |
359 | } | |
360 | ||
361 | GLOBAL_STATE_CODE(); | |
362 | ||
363 | /* Stop things in parent-to-child order */ | |
364 | if (qatomic_fetch_inc(&bs->quiesce_counter) == 0) { | |
365 | bdrv_parent_drained_begin(bs, parent); | |
366 | if (bs->drv && bs->drv->bdrv_drain_begin) { | |
367 | bs->drv->bdrv_drain_begin(bs); | |
368 | } | |
369 | } | |
370 | ||
371 | /* | |
372 | * Wait for drained requests to finish. | |
373 | * | |
374 | * Calling BDRV_POLL_WHILE() only once for the top-level node is okay: The | |
375 | * call is needed so things in this AioContext can make progress even | |
376 | * though we don't return to the main AioContext loop - this automatically | |
377 | * includes other nodes in the same AioContext and therefore all child | |
378 | * nodes. | |
379 | */ | |
380 | if (poll) { | |
381 | BDRV_POLL_WHILE(bs, bdrv_drain_poll_top_level(bs, parent)); | |
382 | } | |
383 | } | |
384 | ||
385 | void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent) | |
386 | { | |
387 | bdrv_do_drained_begin(bs, parent, false); | |
388 | } | |
389 | ||
390 | void bdrv_drained_begin(BlockDriverState *bs) | |
391 | { | |
392 | IO_OR_GS_CODE(); | |
393 | bdrv_do_drained_begin(bs, NULL, true); | |
394 | } | |
395 | ||
396 | /** | |
397 | * This function does not poll, nor must any of its recursively called | |
398 | * functions. | |
399 | */ | |
400 | static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent) | |
401 | { | |
402 | int old_quiesce_counter; | |
403 | ||
404 | IO_OR_GS_CODE(); | |
405 | ||
406 | if (qemu_in_coroutine()) { | |
407 | bdrv_co_yield_to_drain(bs, false, parent, false); | |
408 | return; | |
409 | } | |
410 | assert(bs->quiesce_counter > 0); | |
411 | GLOBAL_STATE_CODE(); | |
412 | ||
413 | /* Re-enable things in child-to-parent order */ | |
414 | old_quiesce_counter = qatomic_fetch_dec(&bs->quiesce_counter); | |
415 | if (old_quiesce_counter == 1) { | |
416 | if (bs->drv && bs->drv->bdrv_drain_end) { | |
417 | bs->drv->bdrv_drain_end(bs); | |
418 | } | |
419 | bdrv_parent_drained_end(bs, parent); | |
420 | } | |
421 | } | |
422 | ||
423 | void bdrv_drained_end(BlockDriverState *bs) | |
424 | { | |
425 | IO_OR_GS_CODE(); | |
426 | bdrv_do_drained_end(bs, NULL); | |
427 | } | |
428 | ||
429 | void bdrv_drain(BlockDriverState *bs) | |
430 | { | |
431 | IO_OR_GS_CODE(); | |
432 | bdrv_drained_begin(bs); | |
433 | bdrv_drained_end(bs); | |
434 | } | |
435 | ||
436 | static void bdrv_drain_assert_idle(BlockDriverState *bs) | |
437 | { | |
438 | BdrvChild *child, *next; | |
439 | ||
440 | assert(qatomic_read(&bs->in_flight) == 0); | |
441 | QLIST_FOREACH_SAFE(child, &bs->children, next, next) { | |
442 | bdrv_drain_assert_idle(child->bs); | |
443 | } | |
444 | } | |
445 | ||
446 | unsigned int bdrv_drain_all_count = 0; | |
447 | ||
448 | static bool bdrv_drain_all_poll(void) | |
449 | { | |
450 | BlockDriverState *bs = NULL; | |
451 | bool result = false; | |
452 | GLOBAL_STATE_CODE(); | |
453 | ||
454 | /* bdrv_drain_poll() can't make changes to the graph and we are holding the | |
455 | * main AioContext lock, so iterating bdrv_next_all_states() is safe. */ | |
456 | while ((bs = bdrv_next_all_states(bs))) { | |
457 | AioContext *aio_context = bdrv_get_aio_context(bs); | |
458 | aio_context_acquire(aio_context); | |
459 | result |= bdrv_drain_poll(bs, NULL, true); | |
460 | aio_context_release(aio_context); | |
461 | } | |
462 | ||
463 | return result; | |
464 | } | |
465 | ||
466 | /* | |
467 | * Wait for pending requests to complete across all BlockDriverStates | |
468 | * | |
469 | * This function does not flush data to disk, use bdrv_flush_all() for that | |
470 | * after calling this function. | |
471 | * | |
472 | * This pauses all block jobs and disables external clients. It must | |
473 | * be paired with bdrv_drain_all_end(). | |
474 | * | |
475 | * NOTE: no new block jobs or BlockDriverStates can be created between | |
476 | * the bdrv_drain_all_begin() and bdrv_drain_all_end() calls. | |
477 | */ | |
478 | void bdrv_drain_all_begin_nopoll(void) | |
479 | { | |
480 | BlockDriverState *bs = NULL; | |
481 | GLOBAL_STATE_CODE(); | |
482 | ||
483 | /* | |
484 | * bdrv queue is managed by record/replay, | |
485 | * waiting for finishing the I/O requests may | |
486 | * be infinite | |
487 | */ | |
488 | if (replay_events_enabled()) { | |
489 | return; | |
490 | } | |
491 | ||
492 | /* AIO_WAIT_WHILE() with a NULL context can only be called from the main | |
493 | * loop AioContext, so make sure we're in the main context. */ | |
494 | assert(qemu_get_current_aio_context() == qemu_get_aio_context()); | |
495 | assert(bdrv_drain_all_count < INT_MAX); | |
496 | bdrv_drain_all_count++; | |
497 | ||
498 | /* Quiesce all nodes, without polling in-flight requests yet. The graph | |
499 | * cannot change during this loop. */ | |
500 | while ((bs = bdrv_next_all_states(bs))) { | |
501 | AioContext *aio_context = bdrv_get_aio_context(bs); | |
502 | ||
503 | aio_context_acquire(aio_context); | |
504 | bdrv_do_drained_begin(bs, NULL, false); | |
505 | aio_context_release(aio_context); | |
506 | } | |
507 | } | |
508 | ||
509 | void bdrv_drain_all_begin(void) | |
510 | { | |
511 | BlockDriverState *bs = NULL; | |
512 | ||
513 | if (qemu_in_coroutine()) { | |
514 | bdrv_co_yield_to_drain(NULL, true, NULL, true); | |
515 | return; | |
516 | } | |
517 | ||
518 | /* | |
519 | * bdrv queue is managed by record/replay, | |
520 | * waiting for finishing the I/O requests may | |
521 | * be infinite | |
522 | */ | |
523 | if (replay_events_enabled()) { | |
524 | return; | |
525 | } | |
526 | ||
527 | bdrv_drain_all_begin_nopoll(); | |
528 | ||
529 | /* Now poll the in-flight requests */ | |
530 | AIO_WAIT_WHILE_UNLOCKED(NULL, bdrv_drain_all_poll()); | |
531 | ||
532 | while ((bs = bdrv_next_all_states(bs))) { | |
533 | bdrv_drain_assert_idle(bs); | |
534 | } | |
535 | } | |
536 | ||
537 | void bdrv_drain_all_end_quiesce(BlockDriverState *bs) | |
538 | { | |
539 | GLOBAL_STATE_CODE(); | |
540 | ||
541 | g_assert(bs->quiesce_counter > 0); | |
542 | g_assert(!bs->refcnt); | |
543 | ||
544 | while (bs->quiesce_counter) { | |
545 | bdrv_do_drained_end(bs, NULL); | |
546 | } | |
547 | } | |
548 | ||
549 | void bdrv_drain_all_end(void) | |
550 | { | |
551 | BlockDriverState *bs = NULL; | |
552 | GLOBAL_STATE_CODE(); | |
553 | ||
554 | /* | |
555 | * bdrv queue is managed by record/replay, | |
556 | * waiting for finishing the I/O requests may | |
557 | * be endless | |
558 | */ | |
559 | if (replay_events_enabled()) { | |
560 | return; | |
561 | } | |
562 | ||
563 | while ((bs = bdrv_next_all_states(bs))) { | |
564 | AioContext *aio_context = bdrv_get_aio_context(bs); | |
565 | ||
566 | aio_context_acquire(aio_context); | |
567 | bdrv_do_drained_end(bs, NULL); | |
568 | aio_context_release(aio_context); | |
569 | } | |
570 | ||
571 | assert(qemu_get_current_aio_context() == qemu_get_aio_context()); | |
572 | assert(bdrv_drain_all_count > 0); | |
573 | bdrv_drain_all_count--; | |
574 | } | |
575 | ||
576 | void bdrv_drain_all(void) | |
577 | { | |
578 | GLOBAL_STATE_CODE(); | |
579 | bdrv_drain_all_begin(); | |
580 | bdrv_drain_all_end(); | |
581 | } | |
582 | ||
583 | /** | |
584 | * Remove an active request from the tracked requests list | |
585 | * | |
586 | * This function should be called when a tracked request is completing. | |
587 | */ | |
588 | static void coroutine_fn tracked_request_end(BdrvTrackedRequest *req) | |
589 | { | |
590 | if (req->serialising) { | |
591 | qatomic_dec(&req->bs->serialising_in_flight); | |
592 | } | |
593 | ||
594 | qemu_mutex_lock(&req->bs->reqs_lock); | |
595 | QLIST_REMOVE(req, list); | |
596 | qemu_mutex_unlock(&req->bs->reqs_lock); | |
597 | ||
598 | /* | |
599 | * At this point qemu_co_queue_wait(&req->wait_queue, ...) won't be called | |
600 | * anymore because the request has been removed from the list, so it's safe | |
601 | * to restart the queue outside reqs_lock to minimize the critical section. | |
602 | */ | |
603 | qemu_co_queue_restart_all(&req->wait_queue); | |
604 | } | |
605 | ||
606 | /** | |
607 | * Add an active request to the tracked requests list | |
608 | */ | |
609 | static void coroutine_fn tracked_request_begin(BdrvTrackedRequest *req, | |
610 | BlockDriverState *bs, | |
611 | int64_t offset, | |
612 | int64_t bytes, | |
613 | enum BdrvTrackedRequestType type) | |
614 | { | |
615 | bdrv_check_request(offset, bytes, &error_abort); | |
616 | ||
617 | *req = (BdrvTrackedRequest){ | |
618 | .bs = bs, | |
619 | .offset = offset, | |
620 | .bytes = bytes, | |
621 | .type = type, | |
622 | .co = qemu_coroutine_self(), | |
623 | .serialising = false, | |
624 | .overlap_offset = offset, | |
625 | .overlap_bytes = bytes, | |
626 | }; | |
627 | ||
628 | qemu_co_queue_init(&req->wait_queue); | |
629 | ||
630 | qemu_mutex_lock(&bs->reqs_lock); | |
631 | QLIST_INSERT_HEAD(&bs->tracked_requests, req, list); | |
632 | qemu_mutex_unlock(&bs->reqs_lock); | |
633 | } | |
634 | ||
635 | static bool tracked_request_overlaps(BdrvTrackedRequest *req, | |
636 | int64_t offset, int64_t bytes) | |
637 | { | |
638 | bdrv_check_request(offset, bytes, &error_abort); | |
639 | ||
640 | /* aaaa bbbb */ | |
641 | if (offset >= req->overlap_offset + req->overlap_bytes) { | |
642 | return false; | |
643 | } | |
644 | /* bbbb aaaa */ | |
645 | if (req->overlap_offset >= offset + bytes) { | |
646 | return false; | |
647 | } | |
648 | return true; | |
649 | } | |
650 | ||
651 | /* Called with self->bs->reqs_lock held */ | |
652 | static coroutine_fn BdrvTrackedRequest * | |
653 | bdrv_find_conflicting_request(BdrvTrackedRequest *self) | |
654 | { | |
655 | BdrvTrackedRequest *req; | |
656 | ||
657 | QLIST_FOREACH(req, &self->bs->tracked_requests, list) { | |
658 | if (req == self || (!req->serialising && !self->serialising)) { | |
659 | continue; | |
660 | } | |
661 | if (tracked_request_overlaps(req, self->overlap_offset, | |
662 | self->overlap_bytes)) | |
663 | { | |
664 | /* | |
665 | * Hitting this means there was a reentrant request, for | |
666 | * example, a block driver issuing nested requests. This must | |
667 | * never happen since it means deadlock. | |
668 | */ | |
669 | assert(qemu_coroutine_self() != req->co); | |
670 | ||
671 | /* | |
672 | * If the request is already (indirectly) waiting for us, or | |
673 | * will wait for us as soon as it wakes up, then just go on | |
674 | * (instead of producing a deadlock in the former case). | |
675 | */ | |
676 | if (!req->waiting_for) { | |
677 | return req; | |
678 | } | |
679 | } | |
680 | } | |
681 | ||
682 | return NULL; | |
683 | } | |
684 | ||
685 | /* Called with self->bs->reqs_lock held */ | |
686 | static void coroutine_fn | |
687 | bdrv_wait_serialising_requests_locked(BdrvTrackedRequest *self) | |
688 | { | |
689 | BdrvTrackedRequest *req; | |
690 | ||
691 | while ((req = bdrv_find_conflicting_request(self))) { | |
692 | self->waiting_for = req; | |
693 | qemu_co_queue_wait(&req->wait_queue, &self->bs->reqs_lock); | |
694 | self->waiting_for = NULL; | |
695 | } | |
696 | } | |
697 | ||
698 | /* Called with req->bs->reqs_lock held */ | |
699 | static void tracked_request_set_serialising(BdrvTrackedRequest *req, | |
700 | uint64_t align) | |
701 | { | |
702 | int64_t overlap_offset = req->offset & ~(align - 1); | |
703 | int64_t overlap_bytes = | |
704 | ROUND_UP(req->offset + req->bytes, align) - overlap_offset; | |
705 | ||
706 | bdrv_check_request(req->offset, req->bytes, &error_abort); | |
707 | ||
708 | if (!req->serialising) { | |
709 | qatomic_inc(&req->bs->serialising_in_flight); | |
710 | req->serialising = true; | |
711 | } | |
712 | ||
713 | req->overlap_offset = MIN(req->overlap_offset, overlap_offset); | |
714 | req->overlap_bytes = MAX(req->overlap_bytes, overlap_bytes); | |
715 | } | |
716 | ||
717 | /** | |
718 | * Return the tracked request on @bs for the current coroutine, or | |
719 | * NULL if there is none. | |
720 | */ | |
721 | BdrvTrackedRequest *coroutine_fn bdrv_co_get_self_request(BlockDriverState *bs) | |
722 | { | |
723 | BdrvTrackedRequest *req; | |
724 | Coroutine *self = qemu_coroutine_self(); | |
725 | IO_CODE(); | |
726 | ||
727 | QLIST_FOREACH(req, &bs->tracked_requests, list) { | |
728 | if (req->co == self) { | |
729 | return req; | |
730 | } | |
731 | } | |
732 | ||
733 | return NULL; | |
734 | } | |
735 | ||
736 | /** | |
737 | * Round a region to subcluster (if supported) or cluster boundaries | |
738 | */ | |
739 | void coroutine_fn GRAPH_RDLOCK | |
740 | bdrv_round_to_subclusters(BlockDriverState *bs, int64_t offset, int64_t bytes, | |
741 | int64_t *align_offset, int64_t *align_bytes) | |
742 | { | |
743 | BlockDriverInfo bdi; | |
744 | IO_CODE(); | |
745 | if (bdrv_co_get_info(bs, &bdi) < 0 || bdi.subcluster_size == 0) { | |
746 | *align_offset = offset; | |
747 | *align_bytes = bytes; | |
748 | } else { | |
749 | int64_t c = bdi.subcluster_size; | |
750 | *align_offset = QEMU_ALIGN_DOWN(offset, c); | |
751 | *align_bytes = QEMU_ALIGN_UP(offset - *align_offset + bytes, c); | |
752 | } | |
753 | } | |
754 | ||
755 | static int coroutine_fn GRAPH_RDLOCK bdrv_get_cluster_size(BlockDriverState *bs) | |
756 | { | |
757 | BlockDriverInfo bdi; | |
758 | int ret; | |
759 | ||
760 | ret = bdrv_co_get_info(bs, &bdi); | |
761 | if (ret < 0 || bdi.cluster_size == 0) { | |
762 | return bs->bl.request_alignment; | |
763 | } else { | |
764 | return bdi.cluster_size; | |
765 | } | |
766 | } | |
767 | ||
768 | void bdrv_inc_in_flight(BlockDriverState *bs) | |
769 | { | |
770 | IO_CODE(); | |
771 | qatomic_inc(&bs->in_flight); | |
772 | } | |
773 | ||
774 | void bdrv_wakeup(BlockDriverState *bs) | |
775 | { | |
776 | IO_CODE(); | |
777 | aio_wait_kick(); | |
778 | } | |
779 | ||
780 | void bdrv_dec_in_flight(BlockDriverState *bs) | |
781 | { | |
782 | IO_CODE(); | |
783 | qatomic_dec(&bs->in_flight); | |
784 | bdrv_wakeup(bs); | |
785 | } | |
786 | ||
787 | static void coroutine_fn | |
788 | bdrv_wait_serialising_requests(BdrvTrackedRequest *self) | |
789 | { | |
790 | BlockDriverState *bs = self->bs; | |
791 | ||
792 | if (!qatomic_read(&bs->serialising_in_flight)) { | |
793 | return; | |
794 | } | |
795 | ||
796 | qemu_mutex_lock(&bs->reqs_lock); | |
797 | bdrv_wait_serialising_requests_locked(self); | |
798 | qemu_mutex_unlock(&bs->reqs_lock); | |
799 | } | |
800 | ||
801 | void coroutine_fn bdrv_make_request_serialising(BdrvTrackedRequest *req, | |
802 | uint64_t align) | |
803 | { | |
804 | IO_CODE(); | |
805 | ||
806 | qemu_mutex_lock(&req->bs->reqs_lock); | |
807 | ||
808 | tracked_request_set_serialising(req, align); | |
809 | bdrv_wait_serialising_requests_locked(req); | |
810 | ||
811 | qemu_mutex_unlock(&req->bs->reqs_lock); | |
812 | } | |
813 | ||
814 | int bdrv_check_qiov_request(int64_t offset, int64_t bytes, | |
815 | QEMUIOVector *qiov, size_t qiov_offset, | |
816 | Error **errp) | |
817 | { | |
818 | /* | |
819 | * Check generic offset/bytes correctness | |
820 | */ | |
821 | ||
822 | if (offset < 0) { | |
823 | error_setg(errp, "offset is negative: %" PRIi64, offset); | |
824 | return -EIO; | |
825 | } | |
826 | ||
827 | if (bytes < 0) { | |
828 | error_setg(errp, "bytes is negative: %" PRIi64, bytes); | |
829 | return -EIO; | |
830 | } | |
831 | ||
832 | if (bytes > BDRV_MAX_LENGTH) { | |
833 | error_setg(errp, "bytes(%" PRIi64 ") exceeds maximum(%" PRIi64 ")", | |
834 | bytes, BDRV_MAX_LENGTH); | |
835 | return -EIO; | |
836 | } | |
837 | ||
838 | if (offset > BDRV_MAX_LENGTH) { | |
839 | error_setg(errp, "offset(%" PRIi64 ") exceeds maximum(%" PRIi64 ")", | |
840 | offset, BDRV_MAX_LENGTH); | |
841 | return -EIO; | |
842 | } | |
843 | ||
844 | if (offset > BDRV_MAX_LENGTH - bytes) { | |
845 | error_setg(errp, "sum of offset(%" PRIi64 ") and bytes(%" PRIi64 ") " | |
846 | "exceeds maximum(%" PRIi64 ")", offset, bytes, | |
847 | BDRV_MAX_LENGTH); | |
848 | return -EIO; | |
849 | } | |
850 | ||
851 | if (!qiov) { | |
852 | return 0; | |
853 | } | |
854 | ||
855 | /* | |
856 | * Check qiov and qiov_offset | |
857 | */ | |
858 | ||
859 | if (qiov_offset > qiov->size) { | |
860 | error_setg(errp, "qiov_offset(%zu) overflow io vector size(%zu)", | |
861 | qiov_offset, qiov->size); | |
862 | return -EIO; | |
863 | } | |
864 | ||
865 | if (bytes > qiov->size - qiov_offset) { | |
866 | error_setg(errp, "bytes(%" PRIi64 ") + qiov_offset(%zu) overflow io " | |
867 | "vector size(%zu)", bytes, qiov_offset, qiov->size); | |
868 | return -EIO; | |
869 | } | |
870 | ||
871 | return 0; | |
872 | } | |
873 | ||
874 | int bdrv_check_request(int64_t offset, int64_t bytes, Error **errp) | |
875 | { | |
876 | return bdrv_check_qiov_request(offset, bytes, NULL, 0, errp); | |
877 | } | |
878 | ||
879 | static int bdrv_check_request32(int64_t offset, int64_t bytes, | |
880 | QEMUIOVector *qiov, size_t qiov_offset) | |
881 | { | |
882 | int ret = bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, NULL); | |
883 | if (ret < 0) { | |
884 | return ret; | |
885 | } | |
886 | ||
887 | if (bytes > BDRV_REQUEST_MAX_BYTES) { | |
888 | return -EIO; | |
889 | } | |
890 | ||
891 | return 0; | |
892 | } | |
893 | ||
894 | /* | |
895 | * Completely zero out a block device with the help of bdrv_pwrite_zeroes. | |
896 | * The operation is sped up by checking the block status and only writing | |
897 | * zeroes to the device if they currently do not return zeroes. Optional | |
898 | * flags are passed through to bdrv_pwrite_zeroes (e.g. BDRV_REQ_MAY_UNMAP, | |
899 | * BDRV_REQ_FUA). | |
900 | * | |
901 | * Returns < 0 on error, 0 on success. For error codes see bdrv_pwrite(). | |
902 | */ | |
903 | int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags) | |
904 | { | |
905 | int ret; | |
906 | int64_t target_size, bytes, offset = 0; | |
907 | BlockDriverState *bs = child->bs; | |
908 | IO_CODE(); | |
909 | ||
910 | target_size = bdrv_getlength(bs); | |
911 | if (target_size < 0) { | |
912 | return target_size; | |
913 | } | |
914 | ||
915 | for (;;) { | |
916 | bytes = MIN(target_size - offset, BDRV_REQUEST_MAX_BYTES); | |
917 | if (bytes <= 0) { | |
918 | return 0; | |
919 | } | |
920 | ret = bdrv_block_status(bs, offset, bytes, &bytes, NULL, NULL); | |
921 | if (ret < 0) { | |
922 | return ret; | |
923 | } | |
924 | if (ret & BDRV_BLOCK_ZERO) { | |
925 | offset += bytes; | |
926 | continue; | |
927 | } | |
928 | ret = bdrv_pwrite_zeroes(child, offset, bytes, flags); | |
929 | if (ret < 0) { | |
930 | return ret; | |
931 | } | |
932 | offset += bytes; | |
933 | } | |
934 | } | |
935 | ||
936 | /* | |
937 | * Writes to the file and ensures that no writes are reordered across this | |
938 | * request (acts as a barrier) | |
939 | * | |
940 | * Returns 0 on success, -errno in error cases. | |
941 | */ | |
942 | int coroutine_fn bdrv_co_pwrite_sync(BdrvChild *child, int64_t offset, | |
943 | int64_t bytes, const void *buf, | |
944 | BdrvRequestFlags flags) | |
945 | { | |
946 | int ret; | |
947 | IO_CODE(); | |
948 | assert_bdrv_graph_readable(); | |
949 | ||
950 | ret = bdrv_co_pwrite(child, offset, bytes, buf, flags); | |
951 | if (ret < 0) { | |
952 | return ret; | |
953 | } | |
954 | ||
955 | ret = bdrv_co_flush(child->bs); | |
956 | if (ret < 0) { | |
957 | return ret; | |
958 | } | |
959 | ||
960 | return 0; | |
961 | } | |
962 | ||
963 | typedef struct CoroutineIOCompletion { | |
964 | Coroutine *coroutine; | |
965 | int ret; | |
966 | } CoroutineIOCompletion; | |
967 | ||
968 | static void bdrv_co_io_em_complete(void *opaque, int ret) | |
969 | { | |
970 | CoroutineIOCompletion *co = opaque; | |
971 | ||
972 | co->ret = ret; | |
973 | aio_co_wake(co->coroutine); | |
974 | } | |
975 | ||
976 | static int coroutine_fn GRAPH_RDLOCK | |
977 | bdrv_driver_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, | |
978 | QEMUIOVector *qiov, size_t qiov_offset, int flags) | |
979 | { | |
980 | BlockDriver *drv = bs->drv; | |
981 | int64_t sector_num; | |
982 | unsigned int nb_sectors; | |
983 | QEMUIOVector local_qiov; | |
984 | int ret; | |
985 | assert_bdrv_graph_readable(); | |
986 | ||
987 | bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort); | |
988 | assert(!(flags & ~bs->supported_read_flags)); | |
989 | ||
990 | if (!drv) { | |
991 | return -ENOMEDIUM; | |
992 | } | |
993 | ||
994 | if (drv->bdrv_co_preadv_part) { | |
995 | return drv->bdrv_co_preadv_part(bs, offset, bytes, qiov, qiov_offset, | |
996 | flags); | |
997 | } | |
998 | ||
999 | if (qiov_offset > 0 || bytes != qiov->size) { | |
1000 | qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes); | |
1001 | qiov = &local_qiov; | |
1002 | } | |
1003 | ||
1004 | if (drv->bdrv_co_preadv) { | |
1005 | ret = drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags); | |
1006 | goto out; | |
1007 | } | |
1008 | ||
1009 | if (drv->bdrv_aio_preadv) { | |
1010 | BlockAIOCB *acb; | |
1011 | CoroutineIOCompletion co = { | |
1012 | .coroutine = qemu_coroutine_self(), | |
1013 | }; | |
1014 | ||
1015 | acb = drv->bdrv_aio_preadv(bs, offset, bytes, qiov, flags, | |
1016 | bdrv_co_io_em_complete, &co); | |
1017 | if (acb == NULL) { | |
1018 | ret = -EIO; | |
1019 | goto out; | |
1020 | } else { | |
1021 | qemu_coroutine_yield(); | |
1022 | ret = co.ret; | |
1023 | goto out; | |
1024 | } | |
1025 | } | |
1026 | ||
1027 | sector_num = offset >> BDRV_SECTOR_BITS; | |
1028 | nb_sectors = bytes >> BDRV_SECTOR_BITS; | |
1029 | ||
1030 | assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE)); | |
1031 | assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE)); | |
1032 | assert(bytes <= BDRV_REQUEST_MAX_BYTES); | |
1033 | assert(drv->bdrv_co_readv); | |
1034 | ||
1035 | ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); | |
1036 | ||
1037 | out: | |
1038 | if (qiov == &local_qiov) { | |
1039 | qemu_iovec_destroy(&local_qiov); | |
1040 | } | |
1041 | ||
1042 | return ret; | |
1043 | } | |
1044 | ||
1045 | static int coroutine_fn GRAPH_RDLOCK | |
1046 | bdrv_driver_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes, | |
1047 | QEMUIOVector *qiov, size_t qiov_offset, | |
1048 | BdrvRequestFlags flags) | |
1049 | { | |
1050 | BlockDriver *drv = bs->drv; | |
1051 | bool emulate_fua = false; | |
1052 | int64_t sector_num; | |
1053 | unsigned int nb_sectors; | |
1054 | QEMUIOVector local_qiov; | |
1055 | int ret; | |
1056 | assert_bdrv_graph_readable(); | |
1057 | ||
1058 | bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort); | |
1059 | ||
1060 | if (!drv) { | |
1061 | return -ENOMEDIUM; | |
1062 | } | |
1063 | ||
1064 | if ((flags & BDRV_REQ_FUA) && | |
1065 | (~bs->supported_write_flags & BDRV_REQ_FUA)) { | |
1066 | flags &= ~BDRV_REQ_FUA; | |
1067 | emulate_fua = true; | |
1068 | } | |
1069 | ||
1070 | flags &= bs->supported_write_flags; | |
1071 | ||
1072 | if (drv->bdrv_co_pwritev_part) { | |
1073 | ret = drv->bdrv_co_pwritev_part(bs, offset, bytes, qiov, qiov_offset, | |
1074 | flags); | |
1075 | goto emulate_flags; | |
1076 | } | |
1077 | ||
1078 | if (qiov_offset > 0 || bytes != qiov->size) { | |
1079 | qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes); | |
1080 | qiov = &local_qiov; | |
1081 | } | |
1082 | ||
1083 | if (drv->bdrv_co_pwritev) { | |
1084 | ret = drv->bdrv_co_pwritev(bs, offset, bytes, qiov, flags); | |
1085 | goto emulate_flags; | |
1086 | } | |
1087 | ||
1088 | if (drv->bdrv_aio_pwritev) { | |
1089 | BlockAIOCB *acb; | |
1090 | CoroutineIOCompletion co = { | |
1091 | .coroutine = qemu_coroutine_self(), | |
1092 | }; | |
1093 | ||
1094 | acb = drv->bdrv_aio_pwritev(bs, offset, bytes, qiov, flags, | |
1095 | bdrv_co_io_em_complete, &co); | |
1096 | if (acb == NULL) { | |
1097 | ret = -EIO; | |
1098 | } else { | |
1099 | qemu_coroutine_yield(); | |
1100 | ret = co.ret; | |
1101 | } | |
1102 | goto emulate_flags; | |
1103 | } | |
1104 | ||
1105 | sector_num = offset >> BDRV_SECTOR_BITS; | |
1106 | nb_sectors = bytes >> BDRV_SECTOR_BITS; | |
1107 | ||
1108 | assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE)); | |
1109 | assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE)); | |
1110 | assert(bytes <= BDRV_REQUEST_MAX_BYTES); | |
1111 | ||
1112 | assert(drv->bdrv_co_writev); | |
1113 | ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov, flags); | |
1114 | ||
1115 | emulate_flags: | |
1116 | if (ret == 0 && emulate_fua) { | |
1117 | ret = bdrv_co_flush(bs); | |
1118 | } | |
1119 | ||
1120 | if (qiov == &local_qiov) { | |
1121 | qemu_iovec_destroy(&local_qiov); | |
1122 | } | |
1123 | ||
1124 | return ret; | |
1125 | } | |
1126 | ||
1127 | static int coroutine_fn GRAPH_RDLOCK | |
1128 | bdrv_driver_pwritev_compressed(BlockDriverState *bs, int64_t offset, | |
1129 | int64_t bytes, QEMUIOVector *qiov, | |
1130 | size_t qiov_offset) | |
1131 | { | |
1132 | BlockDriver *drv = bs->drv; | |
1133 | QEMUIOVector local_qiov; | |
1134 | int ret; | |
1135 | assert_bdrv_graph_readable(); | |
1136 | ||
1137 | bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort); | |
1138 | ||
1139 | if (!drv) { | |
1140 | return -ENOMEDIUM; | |
1141 | } | |
1142 | ||
1143 | if (!block_driver_can_compress(drv)) { | |
1144 | return -ENOTSUP; | |
1145 | } | |
1146 | ||
1147 | if (drv->bdrv_co_pwritev_compressed_part) { | |
1148 | return drv->bdrv_co_pwritev_compressed_part(bs, offset, bytes, | |
1149 | qiov, qiov_offset); | |
1150 | } | |
1151 | ||
1152 | if (qiov_offset == 0) { | |
1153 | return drv->bdrv_co_pwritev_compressed(bs, offset, bytes, qiov); | |
1154 | } | |
1155 | ||
1156 | qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes); | |
1157 | ret = drv->bdrv_co_pwritev_compressed(bs, offset, bytes, &local_qiov); | |
1158 | qemu_iovec_destroy(&local_qiov); | |
1159 | ||
1160 | return ret; | |
1161 | } | |
1162 | ||
1163 | static int coroutine_fn GRAPH_RDLOCK | |
1164 | bdrv_co_do_copy_on_readv(BdrvChild *child, int64_t offset, int64_t bytes, | |
1165 | QEMUIOVector *qiov, size_t qiov_offset, int flags) | |
1166 | { | |
1167 | BlockDriverState *bs = child->bs; | |
1168 | ||
1169 | /* Perform I/O through a temporary buffer so that users who scribble over | |
1170 | * their read buffer while the operation is in progress do not end up | |
1171 | * modifying the image file. This is critical for zero-copy guest I/O | |
1172 | * where anything might happen inside guest memory. | |
1173 | */ | |
1174 | void *bounce_buffer = NULL; | |
1175 | ||
1176 | BlockDriver *drv = bs->drv; | |
1177 | int64_t align_offset; | |
1178 | int64_t align_bytes; | |
1179 | int64_t skip_bytes; | |
1180 | int ret; | |
1181 | int max_transfer = MIN_NON_ZERO(bs->bl.max_transfer, | |
1182 | BDRV_REQUEST_MAX_BYTES); | |
1183 | int64_t progress = 0; | |
1184 | bool skip_write; | |
1185 | ||
1186 | bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort); | |
1187 | ||
1188 | if (!drv) { | |
1189 | return -ENOMEDIUM; | |
1190 | } | |
1191 | ||
1192 | /* | |
1193 | * Do not write anything when the BDS is inactive. That is not | |
1194 | * allowed, and it would not help. | |
1195 | */ | |
1196 | skip_write = (bs->open_flags & BDRV_O_INACTIVE); | |
1197 | ||
1198 | /* FIXME We cannot require callers to have write permissions when all they | |
1199 | * are doing is a read request. If we did things right, write permissions | |
1200 | * would be obtained anyway, but internally by the copy-on-read code. As | |
1201 | * long as it is implemented here rather than in a separate filter driver, | |
1202 | * the copy-on-read code doesn't have its own BdrvChild, however, for which | |
1203 | * it could request permissions. Therefore we have to bypass the permission | |
1204 | * system for the moment. */ | |
1205 | // assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE)); | |
1206 | ||
1207 | /* Cover entire cluster so no additional backing file I/O is required when | |
1208 | * allocating cluster in the image file. Note that this value may exceed | |
1209 | * BDRV_REQUEST_MAX_BYTES (even when the original read did not), which | |
1210 | * is one reason we loop rather than doing it all at once. | |
1211 | */ | |
1212 | bdrv_round_to_subclusters(bs, offset, bytes, &align_offset, &align_bytes); | |
1213 | skip_bytes = offset - align_offset; | |
1214 | ||
1215 | trace_bdrv_co_do_copy_on_readv(bs, offset, bytes, | |
1216 | align_offset, align_bytes); | |
1217 | ||
1218 | while (align_bytes) { | |
1219 | int64_t pnum; | |
1220 | ||
1221 | if (skip_write) { | |
1222 | ret = 1; /* "already allocated", so nothing will be copied */ | |
1223 | pnum = MIN(align_bytes, max_transfer); | |
1224 | } else { | |
1225 | ret = bdrv_is_allocated(bs, align_offset, | |
1226 | MIN(align_bytes, max_transfer), &pnum); | |
1227 | if (ret < 0) { | |
1228 | /* | |
1229 | * Safe to treat errors in querying allocation as if | |
1230 | * unallocated; we'll probably fail again soon on the | |
1231 | * read, but at least that will set a decent errno. | |
1232 | */ | |
1233 | pnum = MIN(align_bytes, max_transfer); | |
1234 | } | |
1235 | ||
1236 | /* Stop at EOF if the image ends in the middle of the cluster */ | |
1237 | if (ret == 0 && pnum == 0) { | |
1238 | assert(progress >= bytes); | |
1239 | break; | |
1240 | } | |
1241 | ||
1242 | assert(skip_bytes < pnum); | |
1243 | } | |
1244 | ||
1245 | if (ret <= 0) { | |
1246 | QEMUIOVector local_qiov; | |
1247 | ||
1248 | /* Must copy-on-read; use the bounce buffer */ | |
1249 | pnum = MIN(pnum, MAX_BOUNCE_BUFFER); | |
1250 | if (!bounce_buffer) { | |
1251 | int64_t max_we_need = MAX(pnum, align_bytes - pnum); | |
1252 | int64_t max_allowed = MIN(max_transfer, MAX_BOUNCE_BUFFER); | |
1253 | int64_t bounce_buffer_len = MIN(max_we_need, max_allowed); | |
1254 | ||
1255 | bounce_buffer = qemu_try_blockalign(bs, bounce_buffer_len); | |
1256 | if (!bounce_buffer) { | |
1257 | ret = -ENOMEM; | |
1258 | goto err; | |
1259 | } | |
1260 | } | |
1261 | qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum); | |
1262 | ||
1263 | ret = bdrv_driver_preadv(bs, align_offset, pnum, | |
1264 | &local_qiov, 0, 0); | |
1265 | if (ret < 0) { | |
1266 | goto err; | |
1267 | } | |
1268 | ||
1269 | bdrv_co_debug_event(bs, BLKDBG_COR_WRITE); | |
1270 | if (drv->bdrv_co_pwrite_zeroes && | |
1271 | buffer_is_zero(bounce_buffer, pnum)) { | |
1272 | /* FIXME: Should we (perhaps conditionally) be setting | |
1273 | * BDRV_REQ_MAY_UNMAP, if it will allow for a sparser copy | |
1274 | * that still correctly reads as zero? */ | |
1275 | ret = bdrv_co_do_pwrite_zeroes(bs, align_offset, pnum, | |
1276 | BDRV_REQ_WRITE_UNCHANGED); | |
1277 | } else { | |
1278 | /* This does not change the data on the disk, it is not | |
1279 | * necessary to flush even in cache=writethrough mode. | |
1280 | */ | |
1281 | ret = bdrv_driver_pwritev(bs, align_offset, pnum, | |
1282 | &local_qiov, 0, | |
1283 | BDRV_REQ_WRITE_UNCHANGED); | |
1284 | } | |
1285 | ||
1286 | if (ret < 0) { | |
1287 | /* It might be okay to ignore write errors for guest | |
1288 | * requests. If this is a deliberate copy-on-read | |
1289 | * then we don't want to ignore the error. Simply | |
1290 | * report it in all cases. | |
1291 | */ | |
1292 | goto err; | |
1293 | } | |
1294 | ||
1295 | if (!(flags & BDRV_REQ_PREFETCH)) { | |
1296 | qemu_iovec_from_buf(qiov, qiov_offset + progress, | |
1297 | bounce_buffer + skip_bytes, | |
1298 | MIN(pnum - skip_bytes, bytes - progress)); | |
1299 | } | |
1300 | } else if (!(flags & BDRV_REQ_PREFETCH)) { | |
1301 | /* Read directly into the destination */ | |
1302 | ret = bdrv_driver_preadv(bs, offset + progress, | |
1303 | MIN(pnum - skip_bytes, bytes - progress), | |
1304 | qiov, qiov_offset + progress, 0); | |
1305 | if (ret < 0) { | |
1306 | goto err; | |
1307 | } | |
1308 | } | |
1309 | ||
1310 | align_offset += pnum; | |
1311 | align_bytes -= pnum; | |
1312 | progress += pnum - skip_bytes; | |
1313 | skip_bytes = 0; | |
1314 | } | |
1315 | ret = 0; | |
1316 | ||
1317 | err: | |
1318 | qemu_vfree(bounce_buffer); | |
1319 | return ret; | |
1320 | } | |
1321 | ||
1322 | /* | |
1323 | * Forwards an already correctly aligned request to the BlockDriver. This | |
1324 | * handles copy on read, zeroing after EOF, and fragmentation of large | |
1325 | * reads; any other features must be implemented by the caller. | |
1326 | */ | |
1327 | static int coroutine_fn GRAPH_RDLOCK | |
1328 | bdrv_aligned_preadv(BdrvChild *child, BdrvTrackedRequest *req, | |
1329 | int64_t offset, int64_t bytes, int64_t align, | |
1330 | QEMUIOVector *qiov, size_t qiov_offset, int flags) | |
1331 | { | |
1332 | BlockDriverState *bs = child->bs; | |
1333 | int64_t total_bytes, max_bytes; | |
1334 | int ret = 0; | |
1335 | int64_t bytes_remaining = bytes; | |
1336 | int max_transfer; | |
1337 | ||
1338 | bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort); | |
1339 | assert(is_power_of_2(align)); | |
1340 | assert((offset & (align - 1)) == 0); | |
1341 | assert((bytes & (align - 1)) == 0); | |
1342 | assert((bs->open_flags & BDRV_O_NO_IO) == 0); | |
1343 | max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX), | |
1344 | align); | |
1345 | ||
1346 | /* | |
1347 | * TODO: We would need a per-BDS .supported_read_flags and | |
1348 | * potential fallback support, if we ever implement any read flags | |
1349 | * to pass through to drivers. For now, there aren't any | |
1350 | * passthrough flags except the BDRV_REQ_REGISTERED_BUF optimization hint. | |
1351 | */ | |
1352 | assert(!(flags & ~(BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH | | |
1353 | BDRV_REQ_REGISTERED_BUF))); | |
1354 | ||
1355 | /* Handle Copy on Read and associated serialisation */ | |
1356 | if (flags & BDRV_REQ_COPY_ON_READ) { | |
1357 | /* If we touch the same cluster it counts as an overlap. This | |
1358 | * guarantees that allocating writes will be serialized and not race | |
1359 | * with each other for the same cluster. For example, in copy-on-read | |
1360 | * it ensures that the CoR read and write operations are atomic and | |
1361 | * guest writes cannot interleave between them. */ | |
1362 | bdrv_make_request_serialising(req, bdrv_get_cluster_size(bs)); | |
1363 | } else { | |
1364 | bdrv_wait_serialising_requests(req); | |
1365 | } | |
1366 | ||
1367 | if (flags & BDRV_REQ_COPY_ON_READ) { | |
1368 | int64_t pnum; | |
1369 | ||
1370 | /* The flag BDRV_REQ_COPY_ON_READ has reached its addressee */ | |
1371 | flags &= ~BDRV_REQ_COPY_ON_READ; | |
1372 | ||
1373 | ret = bdrv_is_allocated(bs, offset, bytes, &pnum); | |
1374 | if (ret < 0) { | |
1375 | goto out; | |
1376 | } | |
1377 | ||
1378 | if (!ret || pnum != bytes) { | |
1379 | ret = bdrv_co_do_copy_on_readv(child, offset, bytes, | |
1380 | qiov, qiov_offset, flags); | |
1381 | goto out; | |
1382 | } else if (flags & BDRV_REQ_PREFETCH) { | |
1383 | goto out; | |
1384 | } | |
1385 | } | |
1386 | ||
1387 | /* Forward the request to the BlockDriver, possibly fragmenting it */ | |
1388 | total_bytes = bdrv_co_getlength(bs); | |
1389 | if (total_bytes < 0) { | |
1390 | ret = total_bytes; | |
1391 | goto out; | |
1392 | } | |
1393 | ||
1394 | assert(!(flags & ~(bs->supported_read_flags | BDRV_REQ_REGISTERED_BUF))); | |
1395 | ||
1396 | max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align); | |
1397 | if (bytes <= max_bytes && bytes <= max_transfer) { | |
1398 | ret = bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, flags); | |
1399 | goto out; | |
1400 | } | |
1401 | ||
1402 | while (bytes_remaining) { | |
1403 | int64_t num; | |
1404 | ||
1405 | if (max_bytes) { | |
1406 | num = MIN(bytes_remaining, MIN(max_bytes, max_transfer)); | |
1407 | assert(num); | |
1408 | ||
1409 | ret = bdrv_driver_preadv(bs, offset + bytes - bytes_remaining, | |
1410 | num, qiov, | |
1411 | qiov_offset + bytes - bytes_remaining, | |
1412 | flags); | |
1413 | max_bytes -= num; | |
1414 | } else { | |
1415 | num = bytes_remaining; | |
1416 | ret = qemu_iovec_memset(qiov, qiov_offset + bytes - bytes_remaining, | |
1417 | 0, bytes_remaining); | |
1418 | } | |
1419 | if (ret < 0) { | |
1420 | goto out; | |
1421 | } | |
1422 | bytes_remaining -= num; | |
1423 | } | |
1424 | ||
1425 | out: | |
1426 | return ret < 0 ? ret : 0; | |
1427 | } | |
1428 | ||
1429 | /* | |
1430 | * Request padding | |
1431 | * | |
1432 | * |<---- align ----->| |<----- align ---->| | |
1433 | * |<- head ->|<------------- bytes ------------->|<-- tail -->| | |
1434 | * | | | | | | | |
1435 | * -*----------$-------*-------- ... --------*-----$------------*--- | |
1436 | * | | | | | | | |
1437 | * | offset | | end | | |
1438 | * ALIGN_DOWN(offset) ALIGN_UP(offset) ALIGN_DOWN(end) ALIGN_UP(end) | |
1439 | * [buf ... ) [tail_buf ) | |
1440 | * | |
1441 | * @buf is an aligned allocation needed to store @head and @tail paddings. @head | |
1442 | * is placed at the beginning of @buf and @tail at the @end. | |
1443 | * | |
1444 | * @tail_buf is a pointer to sub-buffer, corresponding to align-sized chunk | |
1445 | * around tail, if tail exists. | |
1446 | * | |
1447 | * @merge_reads is true for small requests, | |
1448 | * if @buf_len == @head + bytes + @tail. In this case it is possible that both | |
1449 | * head and tail exist but @buf_len == align and @tail_buf == @buf. | |
1450 | * | |
1451 | * @write is true for write requests, false for read requests. | |
1452 | * | |
1453 | * If padding makes the vector too long (exceeding IOV_MAX), then we need to | |
1454 | * merge existing vector elements into a single one. @collapse_bounce_buf acts | |
1455 | * as the bounce buffer in such cases. @pre_collapse_qiov has the pre-collapse | |
1456 | * I/O vector elements so for read requests, the data can be copied back after | |
1457 | * the read is done. | |
1458 | */ | |
1459 | typedef struct BdrvRequestPadding { | |
1460 | uint8_t *buf; | |
1461 | size_t buf_len; | |
1462 | uint8_t *tail_buf; | |
1463 | size_t head; | |
1464 | size_t tail; | |
1465 | bool merge_reads; | |
1466 | bool write; | |
1467 | QEMUIOVector local_qiov; | |
1468 | ||
1469 | uint8_t *collapse_bounce_buf; | |
1470 | size_t collapse_len; | |
1471 | QEMUIOVector pre_collapse_qiov; | |
1472 | } BdrvRequestPadding; | |
1473 | ||
1474 | static bool bdrv_init_padding(BlockDriverState *bs, | |
1475 | int64_t offset, int64_t bytes, | |
1476 | bool write, | |
1477 | BdrvRequestPadding *pad) | |
1478 | { | |
1479 | int64_t align = bs->bl.request_alignment; | |
1480 | int64_t sum; | |
1481 | ||
1482 | bdrv_check_request(offset, bytes, &error_abort); | |
1483 | assert(align <= INT_MAX); /* documented in block/block_int.h */ | |
1484 | assert(align <= SIZE_MAX / 2); /* so we can allocate the buffer */ | |
1485 | ||
1486 | memset(pad, 0, sizeof(*pad)); | |
1487 | ||
1488 | pad->head = offset & (align - 1); | |
1489 | pad->tail = ((offset + bytes) & (align - 1)); | |
1490 | if (pad->tail) { | |
1491 | pad->tail = align - pad->tail; | |
1492 | } | |
1493 | ||
1494 | if (!pad->head && !pad->tail) { | |
1495 | return false; | |
1496 | } | |
1497 | ||
1498 | assert(bytes); /* Nothing good in aligning zero-length requests */ | |
1499 | ||
1500 | sum = pad->head + bytes + pad->tail; | |
1501 | pad->buf_len = (sum > align && pad->head && pad->tail) ? 2 * align : align; | |
1502 | pad->buf = qemu_blockalign(bs, pad->buf_len); | |
1503 | pad->merge_reads = sum == pad->buf_len; | |
1504 | if (pad->tail) { | |
1505 | pad->tail_buf = pad->buf + pad->buf_len - align; | |
1506 | } | |
1507 | ||
1508 | pad->write = write; | |
1509 | ||
1510 | return true; | |
1511 | } | |
1512 | ||
1513 | static int coroutine_fn GRAPH_RDLOCK | |
1514 | bdrv_padding_rmw_read(BdrvChild *child, BdrvTrackedRequest *req, | |
1515 | BdrvRequestPadding *pad, bool zero_middle) | |
1516 | { | |
1517 | QEMUIOVector local_qiov; | |
1518 | BlockDriverState *bs = child->bs; | |
1519 | uint64_t align = bs->bl.request_alignment; | |
1520 | int ret; | |
1521 | ||
1522 | assert(req->serialising && pad->buf); | |
1523 | ||
1524 | if (pad->head || pad->merge_reads) { | |
1525 | int64_t bytes = pad->merge_reads ? pad->buf_len : align; | |
1526 | ||
1527 | qemu_iovec_init_buf(&local_qiov, pad->buf, bytes); | |
1528 | ||
1529 | if (pad->head) { | |
1530 | bdrv_co_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD); | |
1531 | } | |
1532 | if (pad->merge_reads && pad->tail) { | |
1533 | bdrv_co_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL); | |
1534 | } | |
1535 | ret = bdrv_aligned_preadv(child, req, req->overlap_offset, bytes, | |
1536 | align, &local_qiov, 0, 0); | |
1537 | if (ret < 0) { | |
1538 | return ret; | |
1539 | } | |
1540 | if (pad->head) { | |
1541 | bdrv_co_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD); | |
1542 | } | |
1543 | if (pad->merge_reads && pad->tail) { | |
1544 | bdrv_co_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL); | |
1545 | } | |
1546 | ||
1547 | if (pad->merge_reads) { | |
1548 | goto zero_mem; | |
1549 | } | |
1550 | } | |
1551 | ||
1552 | if (pad->tail) { | |
1553 | qemu_iovec_init_buf(&local_qiov, pad->tail_buf, align); | |
1554 | ||
1555 | bdrv_co_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL); | |
1556 | ret = bdrv_aligned_preadv( | |
1557 | child, req, | |
1558 | req->overlap_offset + req->overlap_bytes - align, | |
1559 | align, align, &local_qiov, 0, 0); | |
1560 | if (ret < 0) { | |
1561 | return ret; | |
1562 | } | |
1563 | bdrv_co_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL); | |
1564 | } | |
1565 | ||
1566 | zero_mem: | |
1567 | if (zero_middle) { | |
1568 | memset(pad->buf + pad->head, 0, pad->buf_len - pad->head - pad->tail); | |
1569 | } | |
1570 | ||
1571 | return 0; | |
1572 | } | |
1573 | ||
1574 | /** | |
1575 | * Free *pad's associated buffers, and perform any necessary finalization steps. | |
1576 | */ | |
1577 | static void bdrv_padding_finalize(BdrvRequestPadding *pad) | |
1578 | { | |
1579 | if (pad->collapse_bounce_buf) { | |
1580 | if (!pad->write) { | |
1581 | /* | |
1582 | * If padding required elements in the vector to be collapsed into a | |
1583 | * bounce buffer, copy the bounce buffer content back | |
1584 | */ | |
1585 | qemu_iovec_from_buf(&pad->pre_collapse_qiov, 0, | |
1586 | pad->collapse_bounce_buf, pad->collapse_len); | |
1587 | } | |
1588 | qemu_vfree(pad->collapse_bounce_buf); | |
1589 | qemu_iovec_destroy(&pad->pre_collapse_qiov); | |
1590 | } | |
1591 | if (pad->buf) { | |
1592 | qemu_vfree(pad->buf); | |
1593 | qemu_iovec_destroy(&pad->local_qiov); | |
1594 | } | |
1595 | memset(pad, 0, sizeof(*pad)); | |
1596 | } | |
1597 | ||
1598 | /* | |
1599 | * Create pad->local_qiov by wrapping @iov in the padding head and tail, while | |
1600 | * ensuring that the resulting vector will not exceed IOV_MAX elements. | |
1601 | * | |
1602 | * To ensure this, when necessary, the first two or three elements of @iov are | |
1603 | * merged into pad->collapse_bounce_buf and replaced by a reference to that | |
1604 | * bounce buffer in pad->local_qiov. | |
1605 | * | |
1606 | * After performing a read request, the data from the bounce buffer must be | |
1607 | * copied back into pad->pre_collapse_qiov (e.g. by bdrv_padding_finalize()). | |
1608 | */ | |
1609 | static int bdrv_create_padded_qiov(BlockDriverState *bs, | |
1610 | BdrvRequestPadding *pad, | |
1611 | struct iovec *iov, int niov, | |
1612 | size_t iov_offset, size_t bytes) | |
1613 | { | |
1614 | int padded_niov, surplus_count, collapse_count; | |
1615 | ||
1616 | /* Assert this invariant */ | |
1617 | assert(niov <= IOV_MAX); | |
1618 | ||
1619 | /* | |
1620 | * Cannot pad if resulting length would exceed SIZE_MAX. Returning an error | |
1621 | * to the guest is not ideal, but there is little else we can do. At least | |
1622 | * this will practically never happen on 64-bit systems. | |
1623 | */ | |
1624 | if (SIZE_MAX - pad->head < bytes || | |
1625 | SIZE_MAX - pad->head - bytes < pad->tail) | |
1626 | { | |
1627 | return -EINVAL; | |
1628 | } | |
1629 | ||
1630 | /* Length of the resulting IOV if we just concatenated everything */ | |
1631 | padded_niov = !!pad->head + niov + !!pad->tail; | |
1632 | ||
1633 | qemu_iovec_init(&pad->local_qiov, MIN(padded_niov, IOV_MAX)); | |
1634 | ||
1635 | if (pad->head) { | |
1636 | qemu_iovec_add(&pad->local_qiov, pad->buf, pad->head); | |
1637 | } | |
1638 | ||
1639 | /* | |
1640 | * If padded_niov > IOV_MAX, we cannot just concatenate everything. | |
1641 | * Instead, merge the first two or three elements of @iov to reduce the | |
1642 | * number of vector elements as necessary. | |
1643 | */ | |
1644 | if (padded_niov > IOV_MAX) { | |
1645 | /* | |
1646 | * Only head and tail can have lead to the number of entries exceeding | |
1647 | * IOV_MAX, so we can exceed it by the head and tail at most. We need | |
1648 | * to reduce the number of elements by `surplus_count`, so we merge that | |
1649 | * many elements plus one into one element. | |
1650 | */ | |
1651 | surplus_count = padded_niov - IOV_MAX; | |
1652 | assert(surplus_count <= !!pad->head + !!pad->tail); | |
1653 | collapse_count = surplus_count + 1; | |
1654 | ||
1655 | /* | |
1656 | * Move the elements to collapse into `pad->pre_collapse_qiov`, then | |
1657 | * advance `iov` (and associated variables) by those elements. | |
1658 | */ | |
1659 | qemu_iovec_init(&pad->pre_collapse_qiov, collapse_count); | |
1660 | qemu_iovec_concat_iov(&pad->pre_collapse_qiov, iov, | |
1661 | collapse_count, iov_offset, SIZE_MAX); | |
1662 | iov += collapse_count; | |
1663 | iov_offset = 0; | |
1664 | niov -= collapse_count; | |
1665 | bytes -= pad->pre_collapse_qiov.size; | |
1666 | ||
1667 | /* | |
1668 | * Construct the bounce buffer to match the length of the to-collapse | |
1669 | * vector elements, and for write requests, initialize it with the data | |
1670 | * from those elements. Then add it to `pad->local_qiov`. | |
1671 | */ | |
1672 | pad->collapse_len = pad->pre_collapse_qiov.size; | |
1673 | pad->collapse_bounce_buf = qemu_blockalign(bs, pad->collapse_len); | |
1674 | if (pad->write) { | |
1675 | qemu_iovec_to_buf(&pad->pre_collapse_qiov, 0, | |
1676 | pad->collapse_bounce_buf, pad->collapse_len); | |
1677 | } | |
1678 | qemu_iovec_add(&pad->local_qiov, | |
1679 | pad->collapse_bounce_buf, pad->collapse_len); | |
1680 | } | |
1681 | ||
1682 | qemu_iovec_concat_iov(&pad->local_qiov, iov, niov, iov_offset, bytes); | |
1683 | ||
1684 | if (pad->tail) { | |
1685 | qemu_iovec_add(&pad->local_qiov, | |
1686 | pad->buf + pad->buf_len - pad->tail, pad->tail); | |
1687 | } | |
1688 | ||
1689 | assert(pad->local_qiov.niov == MIN(padded_niov, IOV_MAX)); | |
1690 | return 0; | |
1691 | } | |
1692 | ||
1693 | /* | |
1694 | * bdrv_pad_request | |
1695 | * | |
1696 | * Exchange request parameters with padded request if needed. Don't include RMW | |
1697 | * read of padding, bdrv_padding_rmw_read() should be called separately if | |
1698 | * needed. | |
1699 | * | |
1700 | * @write is true for write requests, false for read requests. | |
1701 | * | |
1702 | * Request parameters (@qiov, &qiov_offset, &offset, &bytes) are in-out: | |
1703 | * - on function start they represent original request | |
1704 | * - on failure or when padding is not needed they are unchanged | |
1705 | * - on success when padding is needed they represent padded request | |
1706 | */ | |
1707 | static int bdrv_pad_request(BlockDriverState *bs, | |
1708 | QEMUIOVector **qiov, size_t *qiov_offset, | |
1709 | int64_t *offset, int64_t *bytes, | |
1710 | bool write, | |
1711 | BdrvRequestPadding *pad, bool *padded, | |
1712 | BdrvRequestFlags *flags) | |
1713 | { | |
1714 | int ret; | |
1715 | struct iovec *sliced_iov; | |
1716 | int sliced_niov; | |
1717 | size_t sliced_head, sliced_tail; | |
1718 | ||
1719 | /* Should have been checked by the caller already */ | |
1720 | ret = bdrv_check_request32(*offset, *bytes, *qiov, *qiov_offset); | |
1721 | if (ret < 0) { | |
1722 | return ret; | |
1723 | } | |
1724 | ||
1725 | if (!bdrv_init_padding(bs, *offset, *bytes, write, pad)) { | |
1726 | if (padded) { | |
1727 | *padded = false; | |
1728 | } | |
1729 | return 0; | |
1730 | } | |
1731 | ||
1732 | sliced_iov = qemu_iovec_slice(*qiov, *qiov_offset, *bytes, | |
1733 | &sliced_head, &sliced_tail, | |
1734 | &sliced_niov); | |
1735 | ||
1736 | /* Guaranteed by bdrv_check_request32() */ | |
1737 | assert(*bytes <= SIZE_MAX); | |
1738 | ret = bdrv_create_padded_qiov(bs, pad, sliced_iov, sliced_niov, | |
1739 | sliced_head, *bytes); | |
1740 | if (ret < 0) { | |
1741 | bdrv_padding_finalize(pad); | |
1742 | return ret; | |
1743 | } | |
1744 | *bytes += pad->head + pad->tail; | |
1745 | *offset -= pad->head; | |
1746 | *qiov = &pad->local_qiov; | |
1747 | *qiov_offset = 0; | |
1748 | if (padded) { | |
1749 | *padded = true; | |
1750 | } | |
1751 | if (flags) { | |
1752 | /* Can't use optimization hint with bounce buffer */ | |
1753 | *flags &= ~BDRV_REQ_REGISTERED_BUF; | |
1754 | } | |
1755 | ||
1756 | return 0; | |
1757 | } | |
1758 | ||
1759 | int coroutine_fn bdrv_co_preadv(BdrvChild *child, | |
1760 | int64_t offset, int64_t bytes, QEMUIOVector *qiov, | |
1761 | BdrvRequestFlags flags) | |
1762 | { | |
1763 | IO_CODE(); | |
1764 | return bdrv_co_preadv_part(child, offset, bytes, qiov, 0, flags); | |
1765 | } | |
1766 | ||
1767 | int coroutine_fn bdrv_co_preadv_part(BdrvChild *child, | |
1768 | int64_t offset, int64_t bytes, | |
1769 | QEMUIOVector *qiov, size_t qiov_offset, | |
1770 | BdrvRequestFlags flags) | |
1771 | { | |
1772 | BlockDriverState *bs = child->bs; | |
1773 | BdrvTrackedRequest req; | |
1774 | BdrvRequestPadding pad; | |
1775 | int ret; | |
1776 | IO_CODE(); | |
1777 | ||
1778 | trace_bdrv_co_preadv_part(bs, offset, bytes, flags); | |
1779 | ||
1780 | if (!bdrv_co_is_inserted(bs)) { | |
1781 | return -ENOMEDIUM; | |
1782 | } | |
1783 | ||
1784 | ret = bdrv_check_request32(offset, bytes, qiov, qiov_offset); | |
1785 | if (ret < 0) { | |
1786 | return ret; | |
1787 | } | |
1788 | ||
1789 | if (bytes == 0 && !QEMU_IS_ALIGNED(offset, bs->bl.request_alignment)) { | |
1790 | /* | |
1791 | * Aligning zero request is nonsense. Even if driver has special meaning | |
1792 | * of zero-length (like qcow2_co_pwritev_compressed_part), we can't pass | |
1793 | * it to driver due to request_alignment. | |
1794 | * | |
1795 | * Still, no reason to return an error if someone do unaligned | |
1796 | * zero-length read occasionally. | |
1797 | */ | |
1798 | return 0; | |
1799 | } | |
1800 | ||
1801 | bdrv_inc_in_flight(bs); | |
1802 | ||
1803 | /* Don't do copy-on-read if we read data before write operation */ | |
1804 | if (qatomic_read(&bs->copy_on_read)) { | |
1805 | flags |= BDRV_REQ_COPY_ON_READ; | |
1806 | } | |
1807 | ||
1808 | ret = bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, false, | |
1809 | &pad, NULL, &flags); | |
1810 | if (ret < 0) { | |
1811 | goto fail; | |
1812 | } | |
1813 | ||
1814 | tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_READ); | |
1815 | ret = bdrv_aligned_preadv(child, &req, offset, bytes, | |
1816 | bs->bl.request_alignment, | |
1817 | qiov, qiov_offset, flags); | |
1818 | tracked_request_end(&req); | |
1819 | bdrv_padding_finalize(&pad); | |
1820 | ||
1821 | fail: | |
1822 | bdrv_dec_in_flight(bs); | |
1823 | ||
1824 | return ret; | |
1825 | } | |
1826 | ||
1827 | static int coroutine_fn GRAPH_RDLOCK | |
1828 | bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int64_t bytes, | |
1829 | BdrvRequestFlags flags) | |
1830 | { | |
1831 | BlockDriver *drv = bs->drv; | |
1832 | QEMUIOVector qiov; | |
1833 | void *buf = NULL; | |
1834 | int ret = 0; | |
1835 | bool need_flush = false; | |
1836 | int head = 0; | |
1837 | int tail = 0; | |
1838 | ||
1839 | int64_t max_write_zeroes = MIN_NON_ZERO(bs->bl.max_pwrite_zeroes, | |
1840 | INT64_MAX); | |
1841 | int alignment = MAX(bs->bl.pwrite_zeroes_alignment, | |
1842 | bs->bl.request_alignment); | |
1843 | int max_transfer = MIN_NON_ZERO(bs->bl.max_transfer, MAX_BOUNCE_BUFFER); | |
1844 | ||
1845 | assert_bdrv_graph_readable(); | |
1846 | bdrv_check_request(offset, bytes, &error_abort); | |
1847 | ||
1848 | if (!drv) { | |
1849 | return -ENOMEDIUM; | |
1850 | } | |
1851 | ||
1852 | if ((flags & ~bs->supported_zero_flags) & BDRV_REQ_NO_FALLBACK) { | |
1853 | return -ENOTSUP; | |
1854 | } | |
1855 | ||
1856 | /* By definition there is no user buffer so this flag doesn't make sense */ | |
1857 | if (flags & BDRV_REQ_REGISTERED_BUF) { | |
1858 | return -EINVAL; | |
1859 | } | |
1860 | ||
1861 | /* Invalidate the cached block-status data range if this write overlaps */ | |
1862 | bdrv_bsc_invalidate_range(bs, offset, bytes); | |
1863 | ||
1864 | assert(alignment % bs->bl.request_alignment == 0); | |
1865 | head = offset % alignment; | |
1866 | tail = (offset + bytes) % alignment; | |
1867 | max_write_zeroes = QEMU_ALIGN_DOWN(max_write_zeroes, alignment); | |
1868 | assert(max_write_zeroes >= bs->bl.request_alignment); | |
1869 | ||
1870 | while (bytes > 0 && !ret) { | |
1871 | int64_t num = bytes; | |
1872 | ||
1873 | /* Align request. Block drivers can expect the "bulk" of the request | |
1874 | * to be aligned, and that unaligned requests do not cross cluster | |
1875 | * boundaries. | |
1876 | */ | |
1877 | if (head) { | |
1878 | /* Make a small request up to the first aligned sector. For | |
1879 | * convenience, limit this request to max_transfer even if | |
1880 | * we don't need to fall back to writes. */ | |
1881 | num = MIN(MIN(bytes, max_transfer), alignment - head); | |
1882 | head = (head + num) % alignment; | |
1883 | assert(num < max_write_zeroes); | |
1884 | } else if (tail && num > alignment) { | |
1885 | /* Shorten the request to the last aligned sector. */ | |
1886 | num -= tail; | |
1887 | } | |
1888 | ||
1889 | /* limit request size */ | |
1890 | if (num > max_write_zeroes) { | |
1891 | num = max_write_zeroes; | |
1892 | } | |
1893 | ||
1894 | ret = -ENOTSUP; | |
1895 | /* First try the efficient write zeroes operation */ | |
1896 | if (drv->bdrv_co_pwrite_zeroes) { | |
1897 | ret = drv->bdrv_co_pwrite_zeroes(bs, offset, num, | |
1898 | flags & bs->supported_zero_flags); | |
1899 | if (ret != -ENOTSUP && (flags & BDRV_REQ_FUA) && | |
1900 | !(bs->supported_zero_flags & BDRV_REQ_FUA)) { | |
1901 | need_flush = true; | |
1902 | } | |
1903 | } else { | |
1904 | assert(!bs->supported_zero_flags); | |
1905 | } | |
1906 | ||
1907 | if (ret == -ENOTSUP && !(flags & BDRV_REQ_NO_FALLBACK)) { | |
1908 | /* Fall back to bounce buffer if write zeroes is unsupported */ | |
1909 | BdrvRequestFlags write_flags = flags & ~BDRV_REQ_ZERO_WRITE; | |
1910 | ||
1911 | if ((flags & BDRV_REQ_FUA) && | |
1912 | !(bs->supported_write_flags & BDRV_REQ_FUA)) { | |
1913 | /* No need for bdrv_driver_pwrite() to do a fallback | |
1914 | * flush on each chunk; use just one at the end */ | |
1915 | write_flags &= ~BDRV_REQ_FUA; | |
1916 | need_flush = true; | |
1917 | } | |
1918 | num = MIN(num, max_transfer); | |
1919 | if (buf == NULL) { | |
1920 | buf = qemu_try_blockalign0(bs, num); | |
1921 | if (buf == NULL) { | |
1922 | ret = -ENOMEM; | |
1923 | goto fail; | |
1924 | } | |
1925 | } | |
1926 | qemu_iovec_init_buf(&qiov, buf, num); | |
1927 | ||
1928 | ret = bdrv_driver_pwritev(bs, offset, num, &qiov, 0, write_flags); | |
1929 | ||
1930 | /* Keep bounce buffer around if it is big enough for all | |
1931 | * all future requests. | |
1932 | */ | |
1933 | if (num < max_transfer) { | |
1934 | qemu_vfree(buf); | |
1935 | buf = NULL; | |
1936 | } | |
1937 | } | |
1938 | ||
1939 | offset += num; | |
1940 | bytes -= num; | |
1941 | } | |
1942 | ||
1943 | fail: | |
1944 | if (ret == 0 && need_flush) { | |
1945 | ret = bdrv_co_flush(bs); | |
1946 | } | |
1947 | qemu_vfree(buf); | |
1948 | return ret; | |
1949 | } | |
1950 | ||
1951 | static inline int coroutine_fn GRAPH_RDLOCK | |
1952 | bdrv_co_write_req_prepare(BdrvChild *child, int64_t offset, int64_t bytes, | |
1953 | BdrvTrackedRequest *req, int flags) | |
1954 | { | |
1955 | BlockDriverState *bs = child->bs; | |
1956 | ||
1957 | bdrv_check_request(offset, bytes, &error_abort); | |
1958 | ||
1959 | if (bdrv_is_read_only(bs)) { | |
1960 | return -EPERM; | |
1961 | } | |
1962 | ||
1963 | assert(!(bs->open_flags & BDRV_O_INACTIVE)); | |
1964 | assert((bs->open_flags & BDRV_O_NO_IO) == 0); | |
1965 | assert(!(flags & ~BDRV_REQ_MASK)); | |
1966 | assert(!((flags & BDRV_REQ_NO_WAIT) && !(flags & BDRV_REQ_SERIALISING))); | |
1967 | ||
1968 | if (flags & BDRV_REQ_SERIALISING) { | |
1969 | QEMU_LOCK_GUARD(&bs->reqs_lock); | |
1970 | ||
1971 | tracked_request_set_serialising(req, bdrv_get_cluster_size(bs)); | |
1972 | ||
1973 | if ((flags & BDRV_REQ_NO_WAIT) && bdrv_find_conflicting_request(req)) { | |
1974 | return -EBUSY; | |
1975 | } | |
1976 | ||
1977 | bdrv_wait_serialising_requests_locked(req); | |
1978 | } else { | |
1979 | bdrv_wait_serialising_requests(req); | |
1980 | } | |
1981 | ||
1982 | assert(req->overlap_offset <= offset); | |
1983 | assert(offset + bytes <= req->overlap_offset + req->overlap_bytes); | |
1984 | assert(offset + bytes <= bs->total_sectors * BDRV_SECTOR_SIZE || | |
1985 | child->perm & BLK_PERM_RESIZE); | |
1986 | ||
1987 | switch (req->type) { | |
1988 | case BDRV_TRACKED_WRITE: | |
1989 | case BDRV_TRACKED_DISCARD: | |
1990 | if (flags & BDRV_REQ_WRITE_UNCHANGED) { | |
1991 | assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE)); | |
1992 | } else { | |
1993 | assert(child->perm & BLK_PERM_WRITE); | |
1994 | } | |
1995 | bdrv_write_threshold_check_write(bs, offset, bytes); | |
1996 | return 0; | |
1997 | case BDRV_TRACKED_TRUNCATE: | |
1998 | assert(child->perm & BLK_PERM_RESIZE); | |
1999 | return 0; | |
2000 | default: | |
2001 | abort(); | |
2002 | } | |
2003 | } | |
2004 | ||
2005 | static inline void coroutine_fn | |
2006 | bdrv_co_write_req_finish(BdrvChild *child, int64_t offset, int64_t bytes, | |
2007 | BdrvTrackedRequest *req, int ret) | |
2008 | { | |
2009 | int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE); | |
2010 | BlockDriverState *bs = child->bs; | |
2011 | ||
2012 | bdrv_check_request(offset, bytes, &error_abort); | |
2013 | ||
2014 | qatomic_inc(&bs->write_gen); | |
2015 | ||
2016 | /* | |
2017 | * Discard cannot extend the image, but in error handling cases, such as | |
2018 | * when reverting a qcow2 cluster allocation, the discarded range can pass | |
2019 | * the end of image file, so we cannot assert about BDRV_TRACKED_DISCARD | |
2020 | * here. Instead, just skip it, since semantically a discard request | |
2021 | * beyond EOF cannot expand the image anyway. | |
2022 | */ | |
2023 | if (ret == 0 && | |
2024 | (req->type == BDRV_TRACKED_TRUNCATE || | |
2025 | end_sector > bs->total_sectors) && | |
2026 | req->type != BDRV_TRACKED_DISCARD) { | |
2027 | bs->total_sectors = end_sector; | |
2028 | bdrv_parent_cb_resize(bs); | |
2029 | bdrv_dirty_bitmap_truncate(bs, end_sector << BDRV_SECTOR_BITS); | |
2030 | } | |
2031 | if (req->bytes) { | |
2032 | switch (req->type) { | |
2033 | case BDRV_TRACKED_WRITE: | |
2034 | stat64_max(&bs->wr_highest_offset, offset + bytes); | |
2035 | /* fall through, to set dirty bits */ | |
2036 | case BDRV_TRACKED_DISCARD: | |
2037 | bdrv_set_dirty(bs, offset, bytes); | |
2038 | break; | |
2039 | default: | |
2040 | break; | |
2041 | } | |
2042 | } | |
2043 | } | |
2044 | ||
2045 | /* | |
2046 | * Forwards an already correctly aligned write request to the BlockDriver, | |
2047 | * after possibly fragmenting it. | |
2048 | */ | |
2049 | static int coroutine_fn GRAPH_RDLOCK | |
2050 | bdrv_aligned_pwritev(BdrvChild *child, BdrvTrackedRequest *req, | |
2051 | int64_t offset, int64_t bytes, int64_t align, | |
2052 | QEMUIOVector *qiov, size_t qiov_offset, | |
2053 | BdrvRequestFlags flags) | |
2054 | { | |
2055 | BlockDriverState *bs = child->bs; | |
2056 | BlockDriver *drv = bs->drv; | |
2057 | int ret; | |
2058 | ||
2059 | int64_t bytes_remaining = bytes; | |
2060 | int max_transfer; | |
2061 | ||
2062 | bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort); | |
2063 | ||
2064 | if (!drv) { | |
2065 | return -ENOMEDIUM; | |
2066 | } | |
2067 | ||
2068 | if (bdrv_has_readonly_bitmaps(bs)) { | |
2069 | return -EPERM; | |
2070 | } | |
2071 | ||
2072 | assert(is_power_of_2(align)); | |
2073 | assert((offset & (align - 1)) == 0); | |
2074 | assert((bytes & (align - 1)) == 0); | |
2075 | max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX), | |
2076 | align); | |
2077 | ||
2078 | ret = bdrv_co_write_req_prepare(child, offset, bytes, req, flags); | |
2079 | ||
2080 | if (!ret && bs->detect_zeroes != BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF && | |
2081 | !(flags & BDRV_REQ_ZERO_WRITE) && drv->bdrv_co_pwrite_zeroes && | |
2082 | qemu_iovec_is_zero(qiov, qiov_offset, bytes)) { | |
2083 | flags |= BDRV_REQ_ZERO_WRITE; | |
2084 | if (bs->detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP) { | |
2085 | flags |= BDRV_REQ_MAY_UNMAP; | |
2086 | } | |
2087 | ||
2088 | /* Can't use optimization hint with bufferless zero write */ | |
2089 | flags &= ~BDRV_REQ_REGISTERED_BUF; | |
2090 | } | |
2091 | ||
2092 | if (ret < 0) { | |
2093 | /* Do nothing, write notifier decided to fail this request */ | |
2094 | } else if (flags & BDRV_REQ_ZERO_WRITE) { | |
2095 | bdrv_co_debug_event(bs, BLKDBG_PWRITEV_ZERO); | |
2096 | ret = bdrv_co_do_pwrite_zeroes(bs, offset, bytes, flags); | |
2097 | } else if (flags & BDRV_REQ_WRITE_COMPRESSED) { | |
2098 | ret = bdrv_driver_pwritev_compressed(bs, offset, bytes, | |
2099 | qiov, qiov_offset); | |
2100 | } else if (bytes <= max_transfer) { | |
2101 | bdrv_co_debug_event(bs, BLKDBG_PWRITEV); | |
2102 | ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, qiov_offset, flags); | |
2103 | } else { | |
2104 | bdrv_co_debug_event(bs, BLKDBG_PWRITEV); | |
2105 | while (bytes_remaining) { | |
2106 | int num = MIN(bytes_remaining, max_transfer); | |
2107 | int local_flags = flags; | |
2108 | ||
2109 | assert(num); | |
2110 | if (num < bytes_remaining && (flags & BDRV_REQ_FUA) && | |
2111 | !(bs->supported_write_flags & BDRV_REQ_FUA)) { | |
2112 | /* If FUA is going to be emulated by flush, we only | |
2113 | * need to flush on the last iteration */ | |
2114 | local_flags &= ~BDRV_REQ_FUA; | |
2115 | } | |
2116 | ||
2117 | ret = bdrv_driver_pwritev(bs, offset + bytes - bytes_remaining, | |
2118 | num, qiov, | |
2119 | qiov_offset + bytes - bytes_remaining, | |
2120 | local_flags); | |
2121 | if (ret < 0) { | |
2122 | break; | |
2123 | } | |
2124 | bytes_remaining -= num; | |
2125 | } | |
2126 | } | |
2127 | bdrv_co_debug_event(bs, BLKDBG_PWRITEV_DONE); | |
2128 | ||
2129 | if (ret >= 0) { | |
2130 | ret = 0; | |
2131 | } | |
2132 | bdrv_co_write_req_finish(child, offset, bytes, req, ret); | |
2133 | ||
2134 | return ret; | |
2135 | } | |
2136 | ||
2137 | static int coroutine_fn GRAPH_RDLOCK | |
2138 | bdrv_co_do_zero_pwritev(BdrvChild *child, int64_t offset, int64_t bytes, | |
2139 | BdrvRequestFlags flags, BdrvTrackedRequest *req) | |
2140 | { | |
2141 | BlockDriverState *bs = child->bs; | |
2142 | QEMUIOVector local_qiov; | |
2143 | uint64_t align = bs->bl.request_alignment; | |
2144 | int ret = 0; | |
2145 | bool padding; | |
2146 | BdrvRequestPadding pad; | |
2147 | ||
2148 | /* This flag doesn't make sense for padding or zero writes */ | |
2149 | flags &= ~BDRV_REQ_REGISTERED_BUF; | |
2150 | ||
2151 | padding = bdrv_init_padding(bs, offset, bytes, true, &pad); | |
2152 | if (padding) { | |
2153 | assert(!(flags & BDRV_REQ_NO_WAIT)); | |
2154 | bdrv_make_request_serialising(req, align); | |
2155 | ||
2156 | bdrv_padding_rmw_read(child, req, &pad, true); | |
2157 | ||
2158 | if (pad.head || pad.merge_reads) { | |
2159 | int64_t aligned_offset = offset & ~(align - 1); | |
2160 | int64_t write_bytes = pad.merge_reads ? pad.buf_len : align; | |
2161 | ||
2162 | qemu_iovec_init_buf(&local_qiov, pad.buf, write_bytes); | |
2163 | ret = bdrv_aligned_pwritev(child, req, aligned_offset, write_bytes, | |
2164 | align, &local_qiov, 0, | |
2165 | flags & ~BDRV_REQ_ZERO_WRITE); | |
2166 | if (ret < 0 || pad.merge_reads) { | |
2167 | /* Error or all work is done */ | |
2168 | goto out; | |
2169 | } | |
2170 | offset += write_bytes - pad.head; | |
2171 | bytes -= write_bytes - pad.head; | |
2172 | } | |
2173 | } | |
2174 | ||
2175 | assert(!bytes || (offset & (align - 1)) == 0); | |
2176 | if (bytes >= align) { | |
2177 | /* Write the aligned part in the middle. */ | |
2178 | int64_t aligned_bytes = bytes & ~(align - 1); | |
2179 | ret = bdrv_aligned_pwritev(child, req, offset, aligned_bytes, align, | |
2180 | NULL, 0, flags); | |
2181 | if (ret < 0) { | |
2182 | goto out; | |
2183 | } | |
2184 | bytes -= aligned_bytes; | |
2185 | offset += aligned_bytes; | |
2186 | } | |
2187 | ||
2188 | assert(!bytes || (offset & (align - 1)) == 0); | |
2189 | if (bytes) { | |
2190 | assert(align == pad.tail + bytes); | |
2191 | ||
2192 | qemu_iovec_init_buf(&local_qiov, pad.tail_buf, align); | |
2193 | ret = bdrv_aligned_pwritev(child, req, offset, align, align, | |
2194 | &local_qiov, 0, | |
2195 | flags & ~BDRV_REQ_ZERO_WRITE); | |
2196 | } | |
2197 | ||
2198 | out: | |
2199 | bdrv_padding_finalize(&pad); | |
2200 | ||
2201 | return ret; | |
2202 | } | |
2203 | ||
2204 | /* | |
2205 | * Handle a write request in coroutine context | |
2206 | */ | |
2207 | int coroutine_fn bdrv_co_pwritev(BdrvChild *child, | |
2208 | int64_t offset, int64_t bytes, QEMUIOVector *qiov, | |
2209 | BdrvRequestFlags flags) | |
2210 | { | |
2211 | IO_CODE(); | |
2212 | return bdrv_co_pwritev_part(child, offset, bytes, qiov, 0, flags); | |
2213 | } | |
2214 | ||
2215 | int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child, | |
2216 | int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset, | |
2217 | BdrvRequestFlags flags) | |
2218 | { | |
2219 | BlockDriverState *bs = child->bs; | |
2220 | BdrvTrackedRequest req; | |
2221 | uint64_t align = bs->bl.request_alignment; | |
2222 | BdrvRequestPadding pad; | |
2223 | int ret; | |
2224 | bool padded = false; | |
2225 | IO_CODE(); | |
2226 | ||
2227 | trace_bdrv_co_pwritev_part(child->bs, offset, bytes, flags); | |
2228 | ||
2229 | if (!bdrv_co_is_inserted(bs)) { | |
2230 | return -ENOMEDIUM; | |
2231 | } | |
2232 | ||
2233 | if (flags & BDRV_REQ_ZERO_WRITE) { | |
2234 | ret = bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, NULL); | |
2235 | } else { | |
2236 | ret = bdrv_check_request32(offset, bytes, qiov, qiov_offset); | |
2237 | } | |
2238 | if (ret < 0) { | |
2239 | return ret; | |
2240 | } | |
2241 | ||
2242 | /* If the request is misaligned then we can't make it efficient */ | |
2243 | if ((flags & BDRV_REQ_NO_FALLBACK) && | |
2244 | !QEMU_IS_ALIGNED(offset | bytes, align)) | |
2245 | { | |
2246 | return -ENOTSUP; | |
2247 | } | |
2248 | ||
2249 | if (bytes == 0 && !QEMU_IS_ALIGNED(offset, bs->bl.request_alignment)) { | |
2250 | /* | |
2251 | * Aligning zero request is nonsense. Even if driver has special meaning | |
2252 | * of zero-length (like qcow2_co_pwritev_compressed_part), we can't pass | |
2253 | * it to driver due to request_alignment. | |
2254 | * | |
2255 | * Still, no reason to return an error if someone do unaligned | |
2256 | * zero-length write occasionally. | |
2257 | */ | |
2258 | return 0; | |
2259 | } | |
2260 | ||
2261 | if (!(flags & BDRV_REQ_ZERO_WRITE)) { | |
2262 | /* | |
2263 | * Pad request for following read-modify-write cycle. | |
2264 | * bdrv_co_do_zero_pwritev() does aligning by itself, so, we do | |
2265 | * alignment only if there is no ZERO flag. | |
2266 | */ | |
2267 | ret = bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, true, | |
2268 | &pad, &padded, &flags); | |
2269 | if (ret < 0) { | |
2270 | return ret; | |
2271 | } | |
2272 | } | |
2273 | ||
2274 | bdrv_inc_in_flight(bs); | |
2275 | tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_WRITE); | |
2276 | ||
2277 | if (flags & BDRV_REQ_ZERO_WRITE) { | |
2278 | assert(!padded); | |
2279 | ret = bdrv_co_do_zero_pwritev(child, offset, bytes, flags, &req); | |
2280 | goto out; | |
2281 | } | |
2282 | ||
2283 | if (padded) { | |
2284 | /* | |
2285 | * Request was unaligned to request_alignment and therefore | |
2286 | * padded. We are going to do read-modify-write, and must | |
2287 | * serialize the request to prevent interactions of the | |
2288 | * widened region with other transactions. | |
2289 | */ | |
2290 | assert(!(flags & BDRV_REQ_NO_WAIT)); | |
2291 | bdrv_make_request_serialising(&req, align); | |
2292 | bdrv_padding_rmw_read(child, &req, &pad, false); | |
2293 | } | |
2294 | ||
2295 | ret = bdrv_aligned_pwritev(child, &req, offset, bytes, align, | |
2296 | qiov, qiov_offset, flags); | |
2297 | ||
2298 | bdrv_padding_finalize(&pad); | |
2299 | ||
2300 | out: | |
2301 | tracked_request_end(&req); | |
2302 | bdrv_dec_in_flight(bs); | |
2303 | ||
2304 | return ret; | |
2305 | } | |
2306 | ||
2307 | int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset, | |
2308 | int64_t bytes, BdrvRequestFlags flags) | |
2309 | { | |
2310 | IO_CODE(); | |
2311 | trace_bdrv_co_pwrite_zeroes(child->bs, offset, bytes, flags); | |
2312 | assert_bdrv_graph_readable(); | |
2313 | ||
2314 | if (!(child->bs->open_flags & BDRV_O_UNMAP)) { | |
2315 | flags &= ~BDRV_REQ_MAY_UNMAP; | |
2316 | } | |
2317 | ||
2318 | return bdrv_co_pwritev(child, offset, bytes, NULL, | |
2319 | BDRV_REQ_ZERO_WRITE | flags); | |
2320 | } | |
2321 | ||
2322 | /* | |
2323 | * Flush ALL BDSes regardless of if they are reachable via a BlkBackend or not. | |
2324 | */ | |
2325 | int bdrv_flush_all(void) | |
2326 | { | |
2327 | BdrvNextIterator it; | |
2328 | BlockDriverState *bs = NULL; | |
2329 | int result = 0; | |
2330 | ||
2331 | GLOBAL_STATE_CODE(); | |
2332 | ||
2333 | /* | |
2334 | * bdrv queue is managed by record/replay, | |
2335 | * creating new flush request for stopping | |
2336 | * the VM may break the determinism | |
2337 | */ | |
2338 | if (replay_events_enabled()) { | |
2339 | return result; | |
2340 | } | |
2341 | ||
2342 | for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { | |
2343 | AioContext *aio_context = bdrv_get_aio_context(bs); | |
2344 | int ret; | |
2345 | ||
2346 | aio_context_acquire(aio_context); | |
2347 | ret = bdrv_flush(bs); | |
2348 | if (ret < 0 && !result) { | |
2349 | result = ret; | |
2350 | } | |
2351 | aio_context_release(aio_context); | |
2352 | } | |
2353 | ||
2354 | return result; | |
2355 | } | |
2356 | ||
2357 | /* | |
2358 | * Returns the allocation status of the specified sectors. | |
2359 | * Drivers not implementing the functionality are assumed to not support | |
2360 | * backing files, hence all their sectors are reported as allocated. | |
2361 | * | |
2362 | * If 'want_zero' is true, the caller is querying for mapping | |
2363 | * purposes, with a focus on valid BDRV_BLOCK_OFFSET_VALID, _DATA, and | |
2364 | * _ZERO where possible; otherwise, the result favors larger 'pnum', | |
2365 | * with a focus on accurate BDRV_BLOCK_ALLOCATED. | |
2366 | * | |
2367 | * If 'offset' is beyond the end of the disk image the return value is | |
2368 | * BDRV_BLOCK_EOF and 'pnum' is set to 0. | |
2369 | * | |
2370 | * 'bytes' is the max value 'pnum' should be set to. If bytes goes | |
2371 | * beyond the end of the disk image it will be clamped; if 'pnum' is set to | |
2372 | * the end of the image, then the returned value will include BDRV_BLOCK_EOF. | |
2373 | * | |
2374 | * 'pnum' is set to the number of bytes (including and immediately | |
2375 | * following the specified offset) that are easily known to be in the | |
2376 | * same allocated/unallocated state. Note that a second call starting | |
2377 | * at the original offset plus returned pnum may have the same status. | |
2378 | * The returned value is non-zero on success except at end-of-file. | |
2379 | * | |
2380 | * Returns negative errno on failure. Otherwise, if the | |
2381 | * BDRV_BLOCK_OFFSET_VALID bit is set, 'map' and 'file' (if non-NULL) are | |
2382 | * set to the host mapping and BDS corresponding to the guest offset. | |
2383 | */ | |
2384 | static int coroutine_fn GRAPH_RDLOCK | |
2385 | bdrv_co_block_status(BlockDriverState *bs, bool want_zero, | |
2386 | int64_t offset, int64_t bytes, | |
2387 | int64_t *pnum, int64_t *map, BlockDriverState **file) | |
2388 | { | |
2389 | int64_t total_size; | |
2390 | int64_t n; /* bytes */ | |
2391 | int ret; | |
2392 | int64_t local_map = 0; | |
2393 | BlockDriverState *local_file = NULL; | |
2394 | int64_t aligned_offset, aligned_bytes; | |
2395 | uint32_t align; | |
2396 | bool has_filtered_child; | |
2397 | ||
2398 | assert(pnum); | |
2399 | assert_bdrv_graph_readable(); | |
2400 | *pnum = 0; | |
2401 | total_size = bdrv_co_getlength(bs); | |
2402 | if (total_size < 0) { | |
2403 | ret = total_size; | |
2404 | goto early_out; | |
2405 | } | |
2406 | ||
2407 | if (offset >= total_size) { | |
2408 | ret = BDRV_BLOCK_EOF; | |
2409 | goto early_out; | |
2410 | } | |
2411 | if (!bytes) { | |
2412 | ret = 0; | |
2413 | goto early_out; | |
2414 | } | |
2415 | ||
2416 | n = total_size - offset; | |
2417 | if (n < bytes) { | |
2418 | bytes = n; | |
2419 | } | |
2420 | ||
2421 | /* Must be non-NULL or bdrv_co_getlength() would have failed */ | |
2422 | assert(bs->drv); | |
2423 | has_filtered_child = bdrv_filter_child(bs); | |
2424 | if (!bs->drv->bdrv_co_block_status && !has_filtered_child) { | |
2425 | *pnum = bytes; | |
2426 | ret = BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED; | |
2427 | if (offset + bytes == total_size) { | |
2428 | ret |= BDRV_BLOCK_EOF; | |
2429 | } | |
2430 | if (bs->drv->protocol_name) { | |
2431 | ret |= BDRV_BLOCK_OFFSET_VALID; | |
2432 | local_map = offset; | |
2433 | local_file = bs; | |
2434 | } | |
2435 | goto early_out; | |
2436 | } | |
2437 | ||
2438 | bdrv_inc_in_flight(bs); | |
2439 | ||
2440 | /* Round out to request_alignment boundaries */ | |
2441 | align = bs->bl.request_alignment; | |
2442 | aligned_offset = QEMU_ALIGN_DOWN(offset, align); | |
2443 | aligned_bytes = ROUND_UP(offset + bytes, align) - aligned_offset; | |
2444 | ||
2445 | if (bs->drv->bdrv_co_block_status) { | |
2446 | /* | |
2447 | * Use the block-status cache only for protocol nodes: Format | |
2448 | * drivers are generally quick to inquire the status, but protocol | |
2449 | * drivers often need to get information from outside of qemu, so | |
2450 | * we do not have control over the actual implementation. There | |
2451 | * have been cases where inquiring the status took an unreasonably | |
2452 | * long time, and we can do nothing in qemu to fix it. | |
2453 | * This is especially problematic for images with large data areas, | |
2454 | * because finding the few holes in them and giving them special | |
2455 | * treatment does not gain much performance. Therefore, we try to | |
2456 | * cache the last-identified data region. | |
2457 | * | |
2458 | * Second, limiting ourselves to protocol nodes allows us to assume | |
2459 | * the block status for data regions to be DATA | OFFSET_VALID, and | |
2460 | * that the host offset is the same as the guest offset. | |
2461 | * | |
2462 | * Note that it is possible that external writers zero parts of | |
2463 | * the cached regions without the cache being invalidated, and so | |
2464 | * we may report zeroes as data. This is not catastrophic, | |
2465 | * however, because reporting zeroes as data is fine. | |
2466 | */ | |
2467 | if (QLIST_EMPTY(&bs->children) && | |
2468 | bdrv_bsc_is_data(bs, aligned_offset, pnum)) | |
2469 | { | |
2470 | ret = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; | |
2471 | local_file = bs; | |
2472 | local_map = aligned_offset; | |
2473 | } else { | |
2474 | ret = bs->drv->bdrv_co_block_status(bs, want_zero, aligned_offset, | |
2475 | aligned_bytes, pnum, &local_map, | |
2476 | &local_file); | |
2477 | ||
2478 | /* | |
2479 | * Note that checking QLIST_EMPTY(&bs->children) is also done when | |
2480 | * the cache is queried above. Technically, we do not need to check | |
2481 | * it here; the worst that can happen is that we fill the cache for | |
2482 | * non-protocol nodes, and then it is never used. However, filling | |
2483 | * the cache requires an RCU update, so double check here to avoid | |
2484 | * such an update if possible. | |
2485 | * | |
2486 | * Check want_zero, because we only want to update the cache when we | |
2487 | * have accurate information about what is zero and what is data. | |
2488 | */ | |
2489 | if (want_zero && | |
2490 | ret == (BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID) && | |
2491 | QLIST_EMPTY(&bs->children)) | |
2492 | { | |
2493 | /* | |
2494 | * When a protocol driver reports BLOCK_OFFSET_VALID, the | |
2495 | * returned local_map value must be the same as the offset we | |
2496 | * have passed (aligned_offset), and local_bs must be the node | |
2497 | * itself. | |
2498 | * Assert this, because we follow this rule when reading from | |
2499 | * the cache (see the `local_file = bs` and | |
2500 | * `local_map = aligned_offset` assignments above), and the | |
2501 | * result the cache delivers must be the same as the driver | |
2502 | * would deliver. | |
2503 | */ | |
2504 | assert(local_file == bs); | |
2505 | assert(local_map == aligned_offset); | |
2506 | bdrv_bsc_fill(bs, aligned_offset, *pnum); | |
2507 | } | |
2508 | } | |
2509 | } else { | |
2510 | /* Default code for filters */ | |
2511 | ||
2512 | local_file = bdrv_filter_bs(bs); | |
2513 | assert(local_file); | |
2514 | ||
2515 | *pnum = aligned_bytes; | |
2516 | local_map = aligned_offset; | |
2517 | ret = BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID; | |
2518 | } | |
2519 | if (ret < 0) { | |
2520 | *pnum = 0; | |
2521 | goto out; | |
2522 | } | |
2523 | ||
2524 | /* | |
2525 | * The driver's result must be a non-zero multiple of request_alignment. | |
2526 | * Clamp pnum and adjust map to original request. | |
2527 | */ | |
2528 | assert(*pnum && QEMU_IS_ALIGNED(*pnum, align) && | |
2529 | align > offset - aligned_offset); | |
2530 | if (ret & BDRV_BLOCK_RECURSE) { | |
2531 | assert(ret & BDRV_BLOCK_DATA); | |
2532 | assert(ret & BDRV_BLOCK_OFFSET_VALID); | |
2533 | assert(!(ret & BDRV_BLOCK_ZERO)); | |
2534 | } | |
2535 | ||
2536 | *pnum -= offset - aligned_offset; | |
2537 | if (*pnum > bytes) { | |
2538 | *pnum = bytes; | |
2539 | } | |
2540 | if (ret & BDRV_BLOCK_OFFSET_VALID) { | |
2541 | local_map += offset - aligned_offset; | |
2542 | } | |
2543 | ||
2544 | if (ret & BDRV_BLOCK_RAW) { | |
2545 | assert(ret & BDRV_BLOCK_OFFSET_VALID && local_file); | |
2546 | ret = bdrv_co_block_status(local_file, want_zero, local_map, | |
2547 | *pnum, pnum, &local_map, &local_file); | |
2548 | goto out; | |
2549 | } | |
2550 | ||
2551 | if (ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ZERO)) { | |
2552 | ret |= BDRV_BLOCK_ALLOCATED; | |
2553 | } else if (bs->drv->supports_backing) { | |
2554 | BlockDriverState *cow_bs = bdrv_cow_bs(bs); | |
2555 | ||
2556 | if (!cow_bs) { | |
2557 | ret |= BDRV_BLOCK_ZERO; | |
2558 | } else if (want_zero) { | |
2559 | int64_t size2 = bdrv_co_getlength(cow_bs); | |
2560 | ||
2561 | if (size2 >= 0 && offset >= size2) { | |
2562 | ret |= BDRV_BLOCK_ZERO; | |
2563 | } | |
2564 | } | |
2565 | } | |
2566 | ||
2567 | if (want_zero && ret & BDRV_BLOCK_RECURSE && | |
2568 | local_file && local_file != bs && | |
2569 | (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) && | |
2570 | (ret & BDRV_BLOCK_OFFSET_VALID)) { | |
2571 | int64_t file_pnum; | |
2572 | int ret2; | |
2573 | ||
2574 | ret2 = bdrv_co_block_status(local_file, want_zero, local_map, | |
2575 | *pnum, &file_pnum, NULL, NULL); | |
2576 | if (ret2 >= 0) { | |
2577 | /* Ignore errors. This is just providing extra information, it | |
2578 | * is useful but not necessary. | |
2579 | */ | |
2580 | if (ret2 & BDRV_BLOCK_EOF && | |
2581 | (!file_pnum || ret2 & BDRV_BLOCK_ZERO)) { | |
2582 | /* | |
2583 | * It is valid for the format block driver to read | |
2584 | * beyond the end of the underlying file's current | |
2585 | * size; such areas read as zero. | |
2586 | */ | |
2587 | ret |= BDRV_BLOCK_ZERO; | |
2588 | } else { | |
2589 | /* Limit request to the range reported by the protocol driver */ | |
2590 | *pnum = file_pnum; | |
2591 | ret |= (ret2 & BDRV_BLOCK_ZERO); | |
2592 | } | |
2593 | } | |
2594 | } | |
2595 | ||
2596 | out: | |
2597 | bdrv_dec_in_flight(bs); | |
2598 | if (ret >= 0 && offset + *pnum == total_size) { | |
2599 | ret |= BDRV_BLOCK_EOF; | |
2600 | } | |
2601 | early_out: | |
2602 | if (file) { | |
2603 | *file = local_file; | |
2604 | } | |
2605 | if (map) { | |
2606 | *map = local_map; | |
2607 | } | |
2608 | return ret; | |
2609 | } | |
2610 | ||
2611 | int coroutine_fn | |
2612 | bdrv_co_common_block_status_above(BlockDriverState *bs, | |
2613 | BlockDriverState *base, | |
2614 | bool include_base, | |
2615 | bool want_zero, | |
2616 | int64_t offset, | |
2617 | int64_t bytes, | |
2618 | int64_t *pnum, | |
2619 | int64_t *map, | |
2620 | BlockDriverState **file, | |
2621 | int *depth) | |
2622 | { | |
2623 | int ret; | |
2624 | BlockDriverState *p; | |
2625 | int64_t eof = 0; | |
2626 | int dummy; | |
2627 | IO_CODE(); | |
2628 | ||
2629 | assert(!include_base || base); /* Can't include NULL base */ | |
2630 | assert_bdrv_graph_readable(); | |
2631 | ||
2632 | if (!depth) { | |
2633 | depth = &dummy; | |
2634 | } | |
2635 | *depth = 0; | |
2636 | ||
2637 | if (!include_base && bs == base) { | |
2638 | *pnum = bytes; | |
2639 | return 0; | |
2640 | } | |
2641 | ||
2642 | ret = bdrv_co_block_status(bs, want_zero, offset, bytes, pnum, map, file); | |
2643 | ++*depth; | |
2644 | if (ret < 0 || *pnum == 0 || ret & BDRV_BLOCK_ALLOCATED || bs == base) { | |
2645 | return ret; | |
2646 | } | |
2647 | ||
2648 | if (ret & BDRV_BLOCK_EOF) { | |
2649 | eof = offset + *pnum; | |
2650 | } | |
2651 | ||
2652 | assert(*pnum <= bytes); | |
2653 | bytes = *pnum; | |
2654 | ||
2655 | for (p = bdrv_filter_or_cow_bs(bs); include_base || p != base; | |
2656 | p = bdrv_filter_or_cow_bs(p)) | |
2657 | { | |
2658 | ret = bdrv_co_block_status(p, want_zero, offset, bytes, pnum, map, | |
2659 | file); | |
2660 | ++*depth; | |
2661 | if (ret < 0) { | |
2662 | return ret; | |
2663 | } | |
2664 | if (*pnum == 0) { | |
2665 | /* | |
2666 | * The top layer deferred to this layer, and because this layer is | |
2667 | * short, any zeroes that we synthesize beyond EOF behave as if they | |
2668 | * were allocated at this layer. | |
2669 | * | |
2670 | * We don't include BDRV_BLOCK_EOF into ret, as upper layer may be | |
2671 | * larger. We'll add BDRV_BLOCK_EOF if needed at function end, see | |
2672 | * below. | |
2673 | */ | |
2674 | assert(ret & BDRV_BLOCK_EOF); | |
2675 | *pnum = bytes; | |
2676 | if (file) { | |
2677 | *file = p; | |
2678 | } | |
2679 | ret = BDRV_BLOCK_ZERO | BDRV_BLOCK_ALLOCATED; | |
2680 | break; | |
2681 | } | |
2682 | if (ret & BDRV_BLOCK_ALLOCATED) { | |
2683 | /* | |
2684 | * We've found the node and the status, we must break. | |
2685 | * | |
2686 | * Drop BDRV_BLOCK_EOF, as it's not for upper layer, which may be | |
2687 | * larger. We'll add BDRV_BLOCK_EOF if needed at function end, see | |
2688 | * below. | |
2689 | */ | |
2690 | ret &= ~BDRV_BLOCK_EOF; | |
2691 | break; | |
2692 | } | |
2693 | ||
2694 | if (p == base) { | |
2695 | assert(include_base); | |
2696 | break; | |
2697 | } | |
2698 | ||
2699 | /* | |
2700 | * OK, [offset, offset + *pnum) region is unallocated on this layer, | |
2701 | * let's continue the diving. | |
2702 | */ | |
2703 | assert(*pnum <= bytes); | |
2704 | bytes = *pnum; | |
2705 | } | |
2706 | ||
2707 | if (offset + *pnum == eof) { | |
2708 | ret |= BDRV_BLOCK_EOF; | |
2709 | } | |
2710 | ||
2711 | return ret; | |
2712 | } | |
2713 | ||
2714 | int coroutine_fn bdrv_co_block_status_above(BlockDriverState *bs, | |
2715 | BlockDriverState *base, | |
2716 | int64_t offset, int64_t bytes, | |
2717 | int64_t *pnum, int64_t *map, | |
2718 | BlockDriverState **file) | |
2719 | { | |
2720 | IO_CODE(); | |
2721 | return bdrv_co_common_block_status_above(bs, base, false, true, offset, | |
2722 | bytes, pnum, map, file, NULL); | |
2723 | } | |
2724 | ||
2725 | int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base, | |
2726 | int64_t offset, int64_t bytes, int64_t *pnum, | |
2727 | int64_t *map, BlockDriverState **file) | |
2728 | { | |
2729 | IO_CODE(); | |
2730 | return bdrv_common_block_status_above(bs, base, false, true, offset, bytes, | |
2731 | pnum, map, file, NULL); | |
2732 | } | |
2733 | ||
2734 | int bdrv_block_status(BlockDriverState *bs, int64_t offset, int64_t bytes, | |
2735 | int64_t *pnum, int64_t *map, BlockDriverState **file) | |
2736 | { | |
2737 | IO_CODE(); | |
2738 | return bdrv_block_status_above(bs, bdrv_filter_or_cow_bs(bs), | |
2739 | offset, bytes, pnum, map, file); | |
2740 | } | |
2741 | ||
2742 | /* | |
2743 | * Check @bs (and its backing chain) to see if the range defined | |
2744 | * by @offset and @bytes is known to read as zeroes. | |
2745 | * Return 1 if that is the case, 0 otherwise and -errno on error. | |
2746 | * This test is meant to be fast rather than accurate so returning 0 | |
2747 | * does not guarantee non-zero data. | |
2748 | */ | |
2749 | int coroutine_fn bdrv_co_is_zero_fast(BlockDriverState *bs, int64_t offset, | |
2750 | int64_t bytes) | |
2751 | { | |
2752 | int ret; | |
2753 | int64_t pnum = bytes; | |
2754 | IO_CODE(); | |
2755 | ||
2756 | if (!bytes) { | |
2757 | return 1; | |
2758 | } | |
2759 | ||
2760 | ret = bdrv_co_common_block_status_above(bs, NULL, false, false, offset, | |
2761 | bytes, &pnum, NULL, NULL, NULL); | |
2762 | ||
2763 | if (ret < 0) { | |
2764 | return ret; | |
2765 | } | |
2766 | ||
2767 | return (pnum == bytes) && (ret & BDRV_BLOCK_ZERO); | |
2768 | } | |
2769 | ||
2770 | int coroutine_fn bdrv_co_is_allocated(BlockDriverState *bs, int64_t offset, | |
2771 | int64_t bytes, int64_t *pnum) | |
2772 | { | |
2773 | int ret; | |
2774 | int64_t dummy; | |
2775 | IO_CODE(); | |
2776 | ||
2777 | ret = bdrv_co_common_block_status_above(bs, bs, true, false, offset, | |
2778 | bytes, pnum ? pnum : &dummy, NULL, | |
2779 | NULL, NULL); | |
2780 | if (ret < 0) { | |
2781 | return ret; | |
2782 | } | |
2783 | return !!(ret & BDRV_BLOCK_ALLOCATED); | |
2784 | } | |
2785 | ||
2786 | int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes, | |
2787 | int64_t *pnum) | |
2788 | { | |
2789 | int ret; | |
2790 | int64_t dummy; | |
2791 | IO_CODE(); | |
2792 | ||
2793 | ret = bdrv_common_block_status_above(bs, bs, true, false, offset, | |
2794 | bytes, pnum ? pnum : &dummy, NULL, | |
2795 | NULL, NULL); | |
2796 | if (ret < 0) { | |
2797 | return ret; | |
2798 | } | |
2799 | return !!(ret & BDRV_BLOCK_ALLOCATED); | |
2800 | } | |
2801 | ||
2802 | /* See bdrv_is_allocated_above for documentation */ | |
2803 | int coroutine_fn bdrv_co_is_allocated_above(BlockDriverState *top, | |
2804 | BlockDriverState *base, | |
2805 | bool include_base, int64_t offset, | |
2806 | int64_t bytes, int64_t *pnum) | |
2807 | { | |
2808 | int depth; | |
2809 | int ret; | |
2810 | IO_CODE(); | |
2811 | ||
2812 | ret = bdrv_co_common_block_status_above(top, base, include_base, false, | |
2813 | offset, bytes, pnum, NULL, NULL, | |
2814 | &depth); | |
2815 | if (ret < 0) { | |
2816 | return ret; | |
2817 | } | |
2818 | ||
2819 | if (ret & BDRV_BLOCK_ALLOCATED) { | |
2820 | return depth; | |
2821 | } | |
2822 | return 0; | |
2823 | } | |
2824 | ||
2825 | /* | |
2826 | * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP] | |
2827 | * | |
2828 | * Return a positive depth if (a prefix of) the given range is allocated | |
2829 | * in any image between BASE and TOP (BASE is only included if include_base | |
2830 | * is set). Depth 1 is TOP, 2 is the first backing layer, and so forth. | |
2831 | * BASE can be NULL to check if the given offset is allocated in any | |
2832 | * image of the chain. Return 0 otherwise, or negative errno on | |
2833 | * failure. | |
2834 | * | |
2835 | * 'pnum' is set to the number of bytes (including and immediately | |
2836 | * following the specified offset) that are known to be in the same | |
2837 | * allocated/unallocated state. Note that a subsequent call starting | |
2838 | * at 'offset + *pnum' may return the same allocation status (in other | |
2839 | * words, the result is not necessarily the maximum possible range); | |
2840 | * but 'pnum' will only be 0 when end of file is reached. | |
2841 | */ | |
2842 | int bdrv_is_allocated_above(BlockDriverState *top, | |
2843 | BlockDriverState *base, | |
2844 | bool include_base, int64_t offset, | |
2845 | int64_t bytes, int64_t *pnum) | |
2846 | { | |
2847 | int depth; | |
2848 | int ret; | |
2849 | IO_CODE(); | |
2850 | ||
2851 | ret = bdrv_common_block_status_above(top, base, include_base, false, | |
2852 | offset, bytes, pnum, NULL, NULL, | |
2853 | &depth); | |
2854 | if (ret < 0) { | |
2855 | return ret; | |
2856 | } | |
2857 | ||
2858 | if (ret & BDRV_BLOCK_ALLOCATED) { | |
2859 | return depth; | |
2860 | } | |
2861 | return 0; | |
2862 | } | |
2863 | ||
2864 | int coroutine_fn | |
2865 | bdrv_co_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) | |
2866 | { | |
2867 | BlockDriver *drv = bs->drv; | |
2868 | BlockDriverState *child_bs = bdrv_primary_bs(bs); | |
2869 | int ret; | |
2870 | IO_CODE(); | |
2871 | assert_bdrv_graph_readable(); | |
2872 | ||
2873 | ret = bdrv_check_qiov_request(pos, qiov->size, qiov, 0, NULL); | |
2874 | if (ret < 0) { | |
2875 | return ret; | |
2876 | } | |
2877 | ||
2878 | if (!drv) { | |
2879 | return -ENOMEDIUM; | |
2880 | } | |
2881 | ||
2882 | bdrv_inc_in_flight(bs); | |
2883 | ||
2884 | if (drv->bdrv_co_load_vmstate) { | |
2885 | ret = drv->bdrv_co_load_vmstate(bs, qiov, pos); | |
2886 | } else if (child_bs) { | |
2887 | ret = bdrv_co_readv_vmstate(child_bs, qiov, pos); | |
2888 | } else { | |
2889 | ret = -ENOTSUP; | |
2890 | } | |
2891 | ||
2892 | bdrv_dec_in_flight(bs); | |
2893 | ||
2894 | return ret; | |
2895 | } | |
2896 | ||
2897 | int coroutine_fn | |
2898 | bdrv_co_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) | |
2899 | { | |
2900 | BlockDriver *drv = bs->drv; | |
2901 | BlockDriverState *child_bs = bdrv_primary_bs(bs); | |
2902 | int ret; | |
2903 | IO_CODE(); | |
2904 | assert_bdrv_graph_readable(); | |
2905 | ||
2906 | ret = bdrv_check_qiov_request(pos, qiov->size, qiov, 0, NULL); | |
2907 | if (ret < 0) { | |
2908 | return ret; | |
2909 | } | |
2910 | ||
2911 | if (!drv) { | |
2912 | return -ENOMEDIUM; | |
2913 | } | |
2914 | ||
2915 | bdrv_inc_in_flight(bs); | |
2916 | ||
2917 | if (drv->bdrv_co_save_vmstate) { | |
2918 | ret = drv->bdrv_co_save_vmstate(bs, qiov, pos); | |
2919 | } else if (child_bs) { | |
2920 | ret = bdrv_co_writev_vmstate(child_bs, qiov, pos); | |
2921 | } else { | |
2922 | ret = -ENOTSUP; | |
2923 | } | |
2924 | ||
2925 | bdrv_dec_in_flight(bs); | |
2926 | ||
2927 | return ret; | |
2928 | } | |
2929 | ||
2930 | int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf, | |
2931 | int64_t pos, int size) | |
2932 | { | |
2933 | QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, size); | |
2934 | int ret = bdrv_writev_vmstate(bs, &qiov, pos); | |
2935 | IO_CODE(); | |
2936 | ||
2937 | return ret < 0 ? ret : size; | |
2938 | } | |
2939 | ||
2940 | int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf, | |
2941 | int64_t pos, int size) | |
2942 | { | |
2943 | QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, size); | |
2944 | int ret = bdrv_readv_vmstate(bs, &qiov, pos); | |
2945 | IO_CODE(); | |
2946 | ||
2947 | return ret < 0 ? ret : size; | |
2948 | } | |
2949 | ||
2950 | /**************************************************************/ | |
2951 | /* async I/Os */ | |
2952 | ||
2953 | void bdrv_aio_cancel(BlockAIOCB *acb) | |
2954 | { | |
2955 | IO_CODE(); | |
2956 | qemu_aio_ref(acb); | |
2957 | bdrv_aio_cancel_async(acb); | |
2958 | while (acb->refcnt > 1) { | |
2959 | if (acb->aiocb_info->get_aio_context) { | |
2960 | aio_poll(acb->aiocb_info->get_aio_context(acb), true); | |
2961 | } else if (acb->bs) { | |
2962 | /* qemu_aio_ref and qemu_aio_unref are not thread-safe, so | |
2963 | * assert that we're not using an I/O thread. Thread-safe | |
2964 | * code should use bdrv_aio_cancel_async exclusively. | |
2965 | */ | |
2966 | assert(bdrv_get_aio_context(acb->bs) == qemu_get_aio_context()); | |
2967 | aio_poll(bdrv_get_aio_context(acb->bs), true); | |
2968 | } else { | |
2969 | abort(); | |
2970 | } | |
2971 | } | |
2972 | qemu_aio_unref(acb); | |
2973 | } | |
2974 | ||
2975 | /* Async version of aio cancel. The caller is not blocked if the acb implements | |
2976 | * cancel_async, otherwise we do nothing and let the request normally complete. | |
2977 | * In either case the completion callback must be called. */ | |
2978 | void bdrv_aio_cancel_async(BlockAIOCB *acb) | |
2979 | { | |
2980 | IO_CODE(); | |
2981 | if (acb->aiocb_info->cancel_async) { | |
2982 | acb->aiocb_info->cancel_async(acb); | |
2983 | } | |
2984 | } | |
2985 | ||
2986 | /**************************************************************/ | |
2987 | /* Coroutine block device emulation */ | |
2988 | ||
2989 | int coroutine_fn bdrv_co_flush(BlockDriverState *bs) | |
2990 | { | |
2991 | BdrvChild *primary_child = bdrv_primary_child(bs); | |
2992 | BdrvChild *child; | |
2993 | int current_gen; | |
2994 | int ret = 0; | |
2995 | IO_CODE(); | |
2996 | ||
2997 | assert_bdrv_graph_readable(); | |
2998 | bdrv_inc_in_flight(bs); | |
2999 | ||
3000 | if (!bdrv_co_is_inserted(bs) || bdrv_is_read_only(bs) || | |
3001 | bdrv_is_sg(bs)) { | |
3002 | goto early_exit; | |
3003 | } | |
3004 | ||
3005 | qemu_mutex_lock(&bs->reqs_lock); | |
3006 | current_gen = qatomic_read(&bs->write_gen); | |
3007 | ||
3008 | /* Wait until any previous flushes are completed */ | |
3009 | while (bs->active_flush_req) { | |
3010 | qemu_co_queue_wait(&bs->flush_queue, &bs->reqs_lock); | |
3011 | } | |
3012 | ||
3013 | /* Flushes reach this point in nondecreasing current_gen order. */ | |
3014 | bs->active_flush_req = true; | |
3015 | qemu_mutex_unlock(&bs->reqs_lock); | |
3016 | ||
3017 | /* Write back all layers by calling one driver function */ | |
3018 | if (bs->drv->bdrv_co_flush) { | |
3019 | ret = bs->drv->bdrv_co_flush(bs); | |
3020 | goto out; | |
3021 | } | |
3022 | ||
3023 | /* Write back cached data to the OS even with cache=unsafe */ | |
3024 | BLKDBG_CO_EVENT(primary_child, BLKDBG_FLUSH_TO_OS); | |
3025 | if (bs->drv->bdrv_co_flush_to_os) { | |
3026 | ret = bs->drv->bdrv_co_flush_to_os(bs); | |
3027 | if (ret < 0) { | |
3028 | goto out; | |
3029 | } | |
3030 | } | |
3031 | ||
3032 | /* But don't actually force it to the disk with cache=unsafe */ | |
3033 | if (bs->open_flags & BDRV_O_NO_FLUSH) { | |
3034 | goto flush_children; | |
3035 | } | |
3036 | ||
3037 | /* Check if we really need to flush anything */ | |
3038 | if (bs->flushed_gen == current_gen) { | |
3039 | goto flush_children; | |
3040 | } | |
3041 | ||
3042 | BLKDBG_CO_EVENT(primary_child, BLKDBG_FLUSH_TO_DISK); | |
3043 | if (!bs->drv) { | |
3044 | /* bs->drv->bdrv_co_flush() might have ejected the BDS | |
3045 | * (even in case of apparent success) */ | |
3046 | ret = -ENOMEDIUM; | |
3047 | goto out; | |
3048 | } | |
3049 | if (bs->drv->bdrv_co_flush_to_disk) { | |
3050 | ret = bs->drv->bdrv_co_flush_to_disk(bs); | |
3051 | } else if (bs->drv->bdrv_aio_flush) { | |
3052 | BlockAIOCB *acb; | |
3053 | CoroutineIOCompletion co = { | |
3054 | .coroutine = qemu_coroutine_self(), | |
3055 | }; | |
3056 | ||
3057 | acb = bs->drv->bdrv_aio_flush(bs, bdrv_co_io_em_complete, &co); | |
3058 | if (acb == NULL) { | |
3059 | ret = -EIO; | |
3060 | } else { | |
3061 | qemu_coroutine_yield(); | |
3062 | ret = co.ret; | |
3063 | } | |
3064 | } else { | |
3065 | /* | |
3066 | * Some block drivers always operate in either writethrough or unsafe | |
3067 | * mode and don't support bdrv_flush therefore. Usually qemu doesn't | |
3068 | * know how the server works (because the behaviour is hardcoded or | |
3069 | * depends on server-side configuration), so we can't ensure that | |
3070 | * everything is safe on disk. Returning an error doesn't work because | |
3071 | * that would break guests even if the server operates in writethrough | |
3072 | * mode. | |
3073 | * | |
3074 | * Let's hope the user knows what he's doing. | |
3075 | */ | |
3076 | ret = 0; | |
3077 | } | |
3078 | ||
3079 | if (ret < 0) { | |
3080 | goto out; | |
3081 | } | |
3082 | ||
3083 | /* Now flush the underlying protocol. It will also have BDRV_O_NO_FLUSH | |
3084 | * in the case of cache=unsafe, so there are no useless flushes. | |
3085 | */ | |
3086 | flush_children: | |
3087 | ret = 0; | |
3088 | QLIST_FOREACH(child, &bs->children, next) { | |
3089 | if (child->perm & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) { | |
3090 | int this_child_ret = bdrv_co_flush(child->bs); | |
3091 | if (!ret) { | |
3092 | ret = this_child_ret; | |
3093 | } | |
3094 | } | |
3095 | } | |
3096 | ||
3097 | out: | |
3098 | /* Notify any pending flushes that we have completed */ | |
3099 | if (ret == 0) { | |
3100 | bs->flushed_gen = current_gen; | |
3101 | } | |
3102 | ||
3103 | qemu_mutex_lock(&bs->reqs_lock); | |
3104 | bs->active_flush_req = false; | |
3105 | /* Return value is ignored - it's ok if wait queue is empty */ | |
3106 | qemu_co_queue_next(&bs->flush_queue); | |
3107 | qemu_mutex_unlock(&bs->reqs_lock); | |
3108 | ||
3109 | early_exit: | |
3110 | bdrv_dec_in_flight(bs); | |
3111 | return ret; | |
3112 | } | |
3113 | ||
3114 | int coroutine_fn bdrv_co_pdiscard(BdrvChild *child, int64_t offset, | |
3115 | int64_t bytes) | |
3116 | { | |
3117 | BdrvTrackedRequest req; | |
3118 | int ret; | |
3119 | int64_t max_pdiscard; | |
3120 | int head, tail, align; | |
3121 | BlockDriverState *bs = child->bs; | |
3122 | IO_CODE(); | |
3123 | assert_bdrv_graph_readable(); | |
3124 | ||
3125 | if (!bs || !bs->drv || !bdrv_co_is_inserted(bs)) { | |
3126 | return -ENOMEDIUM; | |
3127 | } | |
3128 | ||
3129 | if (bdrv_has_readonly_bitmaps(bs)) { | |
3130 | return -EPERM; | |
3131 | } | |
3132 | ||
3133 | ret = bdrv_check_request(offset, bytes, NULL); | |
3134 | if (ret < 0) { | |
3135 | return ret; | |
3136 | } | |
3137 | ||
3138 | /* Do nothing if disabled. */ | |
3139 | if (!(bs->open_flags & BDRV_O_UNMAP)) { | |
3140 | return 0; | |
3141 | } | |
3142 | ||
3143 | if (!bs->drv->bdrv_co_pdiscard && !bs->drv->bdrv_aio_pdiscard) { | |
3144 | return 0; | |
3145 | } | |
3146 | ||
3147 | /* Invalidate the cached block-status data range if this discard overlaps */ | |
3148 | bdrv_bsc_invalidate_range(bs, offset, bytes); | |
3149 | ||
3150 | /* Discard is advisory, but some devices track and coalesce | |
3151 | * unaligned requests, so we must pass everything down rather than | |
3152 | * round here. Still, most devices will just silently ignore | |
3153 | * unaligned requests (by returning -ENOTSUP), so we must fragment | |
3154 | * the request accordingly. */ | |
3155 | align = MAX(bs->bl.pdiscard_alignment, bs->bl.request_alignment); | |
3156 | assert(align % bs->bl.request_alignment == 0); | |
3157 | head = offset % align; | |
3158 | tail = (offset + bytes) % align; | |
3159 | ||
3160 | bdrv_inc_in_flight(bs); | |
3161 | tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_DISCARD); | |
3162 | ||
3163 | ret = bdrv_co_write_req_prepare(child, offset, bytes, &req, 0); | |
3164 | if (ret < 0) { | |
3165 | goto out; | |
3166 | } | |
3167 | ||
3168 | max_pdiscard = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_pdiscard, INT64_MAX), | |
3169 | align); | |
3170 | assert(max_pdiscard >= bs->bl.request_alignment); | |
3171 | ||
3172 | while (bytes > 0) { | |
3173 | int64_t num = bytes; | |
3174 | ||
3175 | if (head) { | |
3176 | /* Make small requests to get to alignment boundaries. */ | |
3177 | num = MIN(bytes, align - head); | |
3178 | if (!QEMU_IS_ALIGNED(num, bs->bl.request_alignment)) { | |
3179 | num %= bs->bl.request_alignment; | |
3180 | } | |
3181 | head = (head + num) % align; | |
3182 | assert(num < max_pdiscard); | |
3183 | } else if (tail) { | |
3184 | if (num > align) { | |
3185 | /* Shorten the request to the last aligned cluster. */ | |
3186 | num -= tail; | |
3187 | } else if (!QEMU_IS_ALIGNED(tail, bs->bl.request_alignment) && | |
3188 | tail > bs->bl.request_alignment) { | |
3189 | tail %= bs->bl.request_alignment; | |
3190 | num -= tail; | |
3191 | } | |
3192 | } | |
3193 | /* limit request size */ | |
3194 | if (num > max_pdiscard) { | |
3195 | num = max_pdiscard; | |
3196 | } | |
3197 | ||
3198 | if (!bs->drv) { | |
3199 | ret = -ENOMEDIUM; | |
3200 | goto out; | |
3201 | } | |
3202 | if (bs->drv->bdrv_co_pdiscard) { | |
3203 | ret = bs->drv->bdrv_co_pdiscard(bs, offset, num); | |
3204 | } else { | |
3205 | BlockAIOCB *acb; | |
3206 | CoroutineIOCompletion co = { | |
3207 | .coroutine = qemu_coroutine_self(), | |
3208 | }; | |
3209 | ||
3210 | acb = bs->drv->bdrv_aio_pdiscard(bs, offset, num, | |
3211 | bdrv_co_io_em_complete, &co); | |
3212 | if (acb == NULL) { | |
3213 | ret = -EIO; | |
3214 | goto out; | |
3215 | } else { | |
3216 | qemu_coroutine_yield(); | |
3217 | ret = co.ret; | |
3218 | } | |
3219 | } | |
3220 | if (ret && ret != -ENOTSUP) { | |
3221 | goto out; | |
3222 | } | |
3223 | ||
3224 | offset += num; | |
3225 | bytes -= num; | |
3226 | } | |
3227 | ret = 0; | |
3228 | out: | |
3229 | bdrv_co_write_req_finish(child, req.offset, req.bytes, &req, ret); | |
3230 | tracked_request_end(&req); | |
3231 | bdrv_dec_in_flight(bs); | |
3232 | return ret; | |
3233 | } | |
3234 | ||
3235 | int coroutine_fn bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf) | |
3236 | { | |
3237 | BlockDriver *drv = bs->drv; | |
3238 | CoroutineIOCompletion co = { | |
3239 | .coroutine = qemu_coroutine_self(), | |
3240 | }; | |
3241 | BlockAIOCB *acb; | |
3242 | IO_CODE(); | |
3243 | assert_bdrv_graph_readable(); | |
3244 | ||
3245 | bdrv_inc_in_flight(bs); | |
3246 | if (!drv || (!drv->bdrv_aio_ioctl && !drv->bdrv_co_ioctl)) { | |
3247 | co.ret = -ENOTSUP; | |
3248 | goto out; | |
3249 | } | |
3250 | ||
3251 | if (drv->bdrv_co_ioctl) { | |
3252 | co.ret = drv->bdrv_co_ioctl(bs, req, buf); | |
3253 | } else { | |
3254 | acb = drv->bdrv_aio_ioctl(bs, req, buf, bdrv_co_io_em_complete, &co); | |
3255 | if (!acb) { | |
3256 | co.ret = -ENOTSUP; | |
3257 | goto out; | |
3258 | } | |
3259 | qemu_coroutine_yield(); | |
3260 | } | |
3261 | out: | |
3262 | bdrv_dec_in_flight(bs); | |
3263 | return co.ret; | |
3264 | } | |
3265 | ||
3266 | int coroutine_fn bdrv_co_zone_report(BlockDriverState *bs, int64_t offset, | |
3267 | unsigned int *nr_zones, | |
3268 | BlockZoneDescriptor *zones) | |
3269 | { | |
3270 | BlockDriver *drv = bs->drv; | |
3271 | CoroutineIOCompletion co = { | |
3272 | .coroutine = qemu_coroutine_self(), | |
3273 | }; | |
3274 | IO_CODE(); | |
3275 | ||
3276 | bdrv_inc_in_flight(bs); | |
3277 | if (!drv || !drv->bdrv_co_zone_report || bs->bl.zoned == BLK_Z_NONE) { | |
3278 | co.ret = -ENOTSUP; | |
3279 | goto out; | |
3280 | } | |
3281 | co.ret = drv->bdrv_co_zone_report(bs, offset, nr_zones, zones); | |
3282 | out: | |
3283 | bdrv_dec_in_flight(bs); | |
3284 | return co.ret; | |
3285 | } | |
3286 | ||
3287 | int coroutine_fn bdrv_co_zone_mgmt(BlockDriverState *bs, BlockZoneOp op, | |
3288 | int64_t offset, int64_t len) | |
3289 | { | |
3290 | BlockDriver *drv = bs->drv; | |
3291 | CoroutineIOCompletion co = { | |
3292 | .coroutine = qemu_coroutine_self(), | |
3293 | }; | |
3294 | IO_CODE(); | |
3295 | ||
3296 | bdrv_inc_in_flight(bs); | |
3297 | if (!drv || !drv->bdrv_co_zone_mgmt || bs->bl.zoned == BLK_Z_NONE) { | |
3298 | co.ret = -ENOTSUP; | |
3299 | goto out; | |
3300 | } | |
3301 | co.ret = drv->bdrv_co_zone_mgmt(bs, op, offset, len); | |
3302 | out: | |
3303 | bdrv_dec_in_flight(bs); | |
3304 | return co.ret; | |
3305 | } | |
3306 | ||
3307 | int coroutine_fn bdrv_co_zone_append(BlockDriverState *bs, int64_t *offset, | |
3308 | QEMUIOVector *qiov, | |
3309 | BdrvRequestFlags flags) | |
3310 | { | |
3311 | int ret; | |
3312 | BlockDriver *drv = bs->drv; | |
3313 | CoroutineIOCompletion co = { | |
3314 | .coroutine = qemu_coroutine_self(), | |
3315 | }; | |
3316 | IO_CODE(); | |
3317 | ||
3318 | ret = bdrv_check_qiov_request(*offset, qiov->size, qiov, 0, NULL); | |
3319 | if (ret < 0) { | |
3320 | return ret; | |
3321 | } | |
3322 | ||
3323 | bdrv_inc_in_flight(bs); | |
3324 | if (!drv || !drv->bdrv_co_zone_append || bs->bl.zoned == BLK_Z_NONE) { | |
3325 | co.ret = -ENOTSUP; | |
3326 | goto out; | |
3327 | } | |
3328 | co.ret = drv->bdrv_co_zone_append(bs, offset, qiov, flags); | |
3329 | out: | |
3330 | bdrv_dec_in_flight(bs); | |
3331 | return co.ret; | |
3332 | } | |
3333 | ||
3334 | void *qemu_blockalign(BlockDriverState *bs, size_t size) | |
3335 | { | |
3336 | IO_CODE(); | |
3337 | return qemu_memalign(bdrv_opt_mem_align(bs), size); | |
3338 | } | |
3339 | ||
3340 | void *qemu_blockalign0(BlockDriverState *bs, size_t size) | |
3341 | { | |
3342 | IO_CODE(); | |
3343 | return memset(qemu_blockalign(bs, size), 0, size); | |
3344 | } | |
3345 | ||
3346 | void *qemu_try_blockalign(BlockDriverState *bs, size_t size) | |
3347 | { | |
3348 | size_t align = bdrv_opt_mem_align(bs); | |
3349 | IO_CODE(); | |
3350 | ||
3351 | /* Ensure that NULL is never returned on success */ | |
3352 | assert(align > 0); | |
3353 | if (size == 0) { | |
3354 | size = align; | |
3355 | } | |
3356 | ||
3357 | return qemu_try_memalign(align, size); | |
3358 | } | |
3359 | ||
3360 | void *qemu_try_blockalign0(BlockDriverState *bs, size_t size) | |
3361 | { | |
3362 | void *mem = qemu_try_blockalign(bs, size); | |
3363 | IO_CODE(); | |
3364 | ||
3365 | if (mem) { | |
3366 | memset(mem, 0, size); | |
3367 | } | |
3368 | ||
3369 | return mem; | |
3370 | } | |
3371 | ||
3372 | /* Helper that undoes bdrv_register_buf() when it fails partway through */ | |
3373 | static void GRAPH_RDLOCK | |
3374 | bdrv_register_buf_rollback(BlockDriverState *bs, void *host, size_t size, | |
3375 | BdrvChild *final_child) | |
3376 | { | |
3377 | BdrvChild *child; | |
3378 | ||
3379 | GLOBAL_STATE_CODE(); | |
3380 | assert_bdrv_graph_readable(); | |
3381 | ||
3382 | QLIST_FOREACH(child, &bs->children, next) { | |
3383 | if (child == final_child) { | |
3384 | break; | |
3385 | } | |
3386 | ||
3387 | bdrv_unregister_buf(child->bs, host, size); | |
3388 | } | |
3389 | ||
3390 | if (bs->drv && bs->drv->bdrv_unregister_buf) { | |
3391 | bs->drv->bdrv_unregister_buf(bs, host, size); | |
3392 | } | |
3393 | } | |
3394 | ||
3395 | bool bdrv_register_buf(BlockDriverState *bs, void *host, size_t size, | |
3396 | Error **errp) | |
3397 | { | |
3398 | BdrvChild *child; | |
3399 | ||
3400 | GLOBAL_STATE_CODE(); | |
3401 | GRAPH_RDLOCK_GUARD_MAINLOOP(); | |
3402 | ||
3403 | if (bs->drv && bs->drv->bdrv_register_buf) { | |
3404 | if (!bs->drv->bdrv_register_buf(bs, host, size, errp)) { | |
3405 | return false; | |
3406 | } | |
3407 | } | |
3408 | QLIST_FOREACH(child, &bs->children, next) { | |
3409 | if (!bdrv_register_buf(child->bs, host, size, errp)) { | |
3410 | bdrv_register_buf_rollback(bs, host, size, child); | |
3411 | return false; | |
3412 | } | |
3413 | } | |
3414 | return true; | |
3415 | } | |
3416 | ||
3417 | void bdrv_unregister_buf(BlockDriverState *bs, void *host, size_t size) | |
3418 | { | |
3419 | BdrvChild *child; | |
3420 | ||
3421 | GLOBAL_STATE_CODE(); | |
3422 | GRAPH_RDLOCK_GUARD_MAINLOOP(); | |
3423 | ||
3424 | if (bs->drv && bs->drv->bdrv_unregister_buf) { | |
3425 | bs->drv->bdrv_unregister_buf(bs, host, size); | |
3426 | } | |
3427 | QLIST_FOREACH(child, &bs->children, next) { | |
3428 | bdrv_unregister_buf(child->bs, host, size); | |
3429 | } | |
3430 | } | |
3431 | ||
3432 | static int coroutine_fn GRAPH_RDLOCK bdrv_co_copy_range_internal( | |
3433 | BdrvChild *src, int64_t src_offset, BdrvChild *dst, | |
3434 | int64_t dst_offset, int64_t bytes, | |
3435 | BdrvRequestFlags read_flags, BdrvRequestFlags write_flags, | |
3436 | bool recurse_src) | |
3437 | { | |
3438 | BdrvTrackedRequest req; | |
3439 | int ret; | |
3440 | assert_bdrv_graph_readable(); | |
3441 | ||
3442 | /* TODO We can support BDRV_REQ_NO_FALLBACK here */ | |
3443 | assert(!(read_flags & BDRV_REQ_NO_FALLBACK)); | |
3444 | assert(!(write_flags & BDRV_REQ_NO_FALLBACK)); | |
3445 | assert(!(read_flags & BDRV_REQ_NO_WAIT)); | |
3446 | assert(!(write_flags & BDRV_REQ_NO_WAIT)); | |
3447 | ||
3448 | if (!dst || !dst->bs || !bdrv_co_is_inserted(dst->bs)) { | |
3449 | return -ENOMEDIUM; | |
3450 | } | |
3451 | ret = bdrv_check_request32(dst_offset, bytes, NULL, 0); | |
3452 | if (ret) { | |
3453 | return ret; | |
3454 | } | |
3455 | if (write_flags & BDRV_REQ_ZERO_WRITE) { | |
3456 | return bdrv_co_pwrite_zeroes(dst, dst_offset, bytes, write_flags); | |
3457 | } | |
3458 | ||
3459 | if (!src || !src->bs || !bdrv_co_is_inserted(src->bs)) { | |
3460 | return -ENOMEDIUM; | |
3461 | } | |
3462 | ret = bdrv_check_request32(src_offset, bytes, NULL, 0); | |
3463 | if (ret) { | |
3464 | return ret; | |
3465 | } | |
3466 | ||
3467 | if (!src->bs->drv->bdrv_co_copy_range_from | |
3468 | || !dst->bs->drv->bdrv_co_copy_range_to | |
3469 | || src->bs->encrypted || dst->bs->encrypted) { | |
3470 | return -ENOTSUP; | |
3471 | } | |
3472 | ||
3473 | if (recurse_src) { | |
3474 | bdrv_inc_in_flight(src->bs); | |
3475 | tracked_request_begin(&req, src->bs, src_offset, bytes, | |
3476 | BDRV_TRACKED_READ); | |
3477 | ||
3478 | /* BDRV_REQ_SERIALISING is only for write operation */ | |
3479 | assert(!(read_flags & BDRV_REQ_SERIALISING)); | |
3480 | bdrv_wait_serialising_requests(&req); | |
3481 | ||
3482 | ret = src->bs->drv->bdrv_co_copy_range_from(src->bs, | |
3483 | src, src_offset, | |
3484 | dst, dst_offset, | |
3485 | bytes, | |
3486 | read_flags, write_flags); | |
3487 | ||
3488 | tracked_request_end(&req); | |
3489 | bdrv_dec_in_flight(src->bs); | |
3490 | } else { | |
3491 | bdrv_inc_in_flight(dst->bs); | |
3492 | tracked_request_begin(&req, dst->bs, dst_offset, bytes, | |
3493 | BDRV_TRACKED_WRITE); | |
3494 | ret = bdrv_co_write_req_prepare(dst, dst_offset, bytes, &req, | |
3495 | write_flags); | |
3496 | if (!ret) { | |
3497 | ret = dst->bs->drv->bdrv_co_copy_range_to(dst->bs, | |
3498 | src, src_offset, | |
3499 | dst, dst_offset, | |
3500 | bytes, | |
3501 | read_flags, write_flags); | |
3502 | } | |
3503 | bdrv_co_write_req_finish(dst, dst_offset, bytes, &req, ret); | |
3504 | tracked_request_end(&req); | |
3505 | bdrv_dec_in_flight(dst->bs); | |
3506 | } | |
3507 | ||
3508 | return ret; | |
3509 | } | |
3510 | ||
3511 | /* Copy range from @src to @dst. | |
3512 | * | |
3513 | * See the comment of bdrv_co_copy_range for the parameter and return value | |
3514 | * semantics. */ | |
3515 | int coroutine_fn bdrv_co_copy_range_from(BdrvChild *src, int64_t src_offset, | |
3516 | BdrvChild *dst, int64_t dst_offset, | |
3517 | int64_t bytes, | |
3518 | BdrvRequestFlags read_flags, | |
3519 | BdrvRequestFlags write_flags) | |
3520 | { | |
3521 | IO_CODE(); | |
3522 | assert_bdrv_graph_readable(); | |
3523 | trace_bdrv_co_copy_range_from(src, src_offset, dst, dst_offset, bytes, | |
3524 | read_flags, write_flags); | |
3525 | return bdrv_co_copy_range_internal(src, src_offset, dst, dst_offset, | |
3526 | bytes, read_flags, write_flags, true); | |
3527 | } | |
3528 | ||
3529 | /* Copy range from @src to @dst. | |
3530 | * | |
3531 | * See the comment of bdrv_co_copy_range for the parameter and return value | |
3532 | * semantics. */ | |
3533 | int coroutine_fn bdrv_co_copy_range_to(BdrvChild *src, int64_t src_offset, | |
3534 | BdrvChild *dst, int64_t dst_offset, | |
3535 | int64_t bytes, | |
3536 | BdrvRequestFlags read_flags, | |
3537 | BdrvRequestFlags write_flags) | |
3538 | { | |
3539 | IO_CODE(); | |
3540 | assert_bdrv_graph_readable(); | |
3541 | trace_bdrv_co_copy_range_to(src, src_offset, dst, dst_offset, bytes, | |
3542 | read_flags, write_flags); | |
3543 | return bdrv_co_copy_range_internal(src, src_offset, dst, dst_offset, | |
3544 | bytes, read_flags, write_flags, false); | |
3545 | } | |
3546 | ||
3547 | int coroutine_fn bdrv_co_copy_range(BdrvChild *src, int64_t src_offset, | |
3548 | BdrvChild *dst, int64_t dst_offset, | |
3549 | int64_t bytes, BdrvRequestFlags read_flags, | |
3550 | BdrvRequestFlags write_flags) | |
3551 | { | |
3552 | IO_CODE(); | |
3553 | assert_bdrv_graph_readable(); | |
3554 | ||
3555 | return bdrv_co_copy_range_from(src, src_offset, | |
3556 | dst, dst_offset, | |
3557 | bytes, read_flags, write_flags); | |
3558 | } | |
3559 | ||
3560 | static void bdrv_parent_cb_resize(BlockDriverState *bs) | |
3561 | { | |
3562 | BdrvChild *c; | |
3563 | QLIST_FOREACH(c, &bs->parents, next_parent) { | |
3564 | if (c->klass->resize) { | |
3565 | c->klass->resize(c); | |
3566 | } | |
3567 | } | |
3568 | } | |
3569 | ||
3570 | /** | |
3571 | * Truncate file to 'offset' bytes (needed only for file protocols) | |
3572 | * | |
3573 | * If 'exact' is true, the file must be resized to exactly the given | |
3574 | * 'offset'. Otherwise, it is sufficient for the node to be at least | |
3575 | * 'offset' bytes in length. | |
3576 | */ | |
3577 | int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact, | |
3578 | PreallocMode prealloc, BdrvRequestFlags flags, | |
3579 | Error **errp) | |
3580 | { | |
3581 | BlockDriverState *bs = child->bs; | |
3582 | BdrvChild *filtered, *backing; | |
3583 | BlockDriver *drv = bs->drv; | |
3584 | BdrvTrackedRequest req; | |
3585 | int64_t old_size, new_bytes; | |
3586 | int ret; | |
3587 | IO_CODE(); | |
3588 | assert_bdrv_graph_readable(); | |
3589 | ||
3590 | /* if bs->drv == NULL, bs is closed, so there's nothing to do here */ | |
3591 | if (!drv) { | |
3592 | error_setg(errp, "No medium inserted"); | |
3593 | return -ENOMEDIUM; | |
3594 | } | |
3595 | if (offset < 0) { | |
3596 | error_setg(errp, "Image size cannot be negative"); | |
3597 | return -EINVAL; | |
3598 | } | |
3599 | ||
3600 | ret = bdrv_check_request(offset, 0, errp); | |
3601 | if (ret < 0) { | |
3602 | return ret; | |
3603 | } | |
3604 | ||
3605 | old_size = bdrv_co_getlength(bs); | |
3606 | if (old_size < 0) { | |
3607 | error_setg_errno(errp, -old_size, "Failed to get old image size"); | |
3608 | return old_size; | |
3609 | } | |
3610 | ||
3611 | if (bdrv_is_read_only(bs)) { | |
3612 | error_setg(errp, "Image is read-only"); | |
3613 | return -EACCES; | |
3614 | } | |
3615 | ||
3616 | if (offset > old_size) { | |
3617 | new_bytes = offset - old_size; | |
3618 | } else { | |
3619 | new_bytes = 0; | |
3620 | } | |
3621 | ||
3622 | bdrv_inc_in_flight(bs); | |
3623 | tracked_request_begin(&req, bs, offset - new_bytes, new_bytes, | |
3624 | BDRV_TRACKED_TRUNCATE); | |
3625 | ||
3626 | /* If we are growing the image and potentially using preallocation for the | |
3627 | * new area, we need to make sure that no write requests are made to it | |
3628 | * concurrently or they might be overwritten by preallocation. */ | |
3629 | if (new_bytes) { | |
3630 | bdrv_make_request_serialising(&req, 1); | |
3631 | } | |
3632 | ret = bdrv_co_write_req_prepare(child, offset - new_bytes, new_bytes, &req, | |
3633 | 0); | |
3634 | if (ret < 0) { | |
3635 | error_setg_errno(errp, -ret, | |
3636 | "Failed to prepare request for truncation"); | |
3637 | goto out; | |
3638 | } | |
3639 | ||
3640 | filtered = bdrv_filter_child(bs); | |
3641 | backing = bdrv_cow_child(bs); | |
3642 | ||
3643 | /* | |
3644 | * If the image has a backing file that is large enough that it would | |
3645 | * provide data for the new area, we cannot leave it unallocated because | |
3646 | * then the backing file content would become visible. Instead, zero-fill | |
3647 | * the new area. | |
3648 | * | |
3649 | * Note that if the image has a backing file, but was opened without the | |
3650 | * backing file, taking care of keeping things consistent with that backing | |
3651 | * file is the user's responsibility. | |
3652 | */ | |
3653 | if (new_bytes && backing) { | |
3654 | int64_t backing_len; | |
3655 | ||
3656 | backing_len = bdrv_co_getlength(backing->bs); | |
3657 | if (backing_len < 0) { | |
3658 | ret = backing_len; | |
3659 | error_setg_errno(errp, -ret, "Could not get backing file size"); | |
3660 | goto out; | |
3661 | } | |
3662 | ||
3663 | if (backing_len > old_size) { | |
3664 | flags |= BDRV_REQ_ZERO_WRITE; | |
3665 | } | |
3666 | } | |
3667 | ||
3668 | if (drv->bdrv_co_truncate) { | |
3669 | if (flags & ~bs->supported_truncate_flags) { | |
3670 | error_setg(errp, "Block driver does not support requested flags"); | |
3671 | ret = -ENOTSUP; | |
3672 | goto out; | |
3673 | } | |
3674 | ret = drv->bdrv_co_truncate(bs, offset, exact, prealloc, flags, errp); | |
3675 | } else if (filtered) { | |
3676 | ret = bdrv_co_truncate(filtered, offset, exact, prealloc, flags, errp); | |
3677 | } else { | |
3678 | error_setg(errp, "Image format driver does not support resize"); | |
3679 | ret = -ENOTSUP; | |
3680 | goto out; | |
3681 | } | |
3682 | if (ret < 0) { | |
3683 | goto out; | |
3684 | } | |
3685 | ||
3686 | ret = bdrv_co_refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS); | |
3687 | if (ret < 0) { | |
3688 | error_setg_errno(errp, -ret, "Could not refresh total sector count"); | |
3689 | } else { | |
3690 | offset = bs->total_sectors * BDRV_SECTOR_SIZE; | |
3691 | } | |
3692 | /* | |
3693 | * It's possible that truncation succeeded but bdrv_refresh_total_sectors | |
3694 | * failed, but the latter doesn't affect how we should finish the request. | |
3695 | * Pass 0 as the last parameter so that dirty bitmaps etc. are handled. | |
3696 | */ | |
3697 | bdrv_co_write_req_finish(child, offset - new_bytes, new_bytes, &req, 0); | |
3698 | ||
3699 | out: | |
3700 | tracked_request_end(&req); | |
3701 | bdrv_dec_in_flight(bs); | |
3702 | ||
3703 | return ret; | |
3704 | } | |
3705 | ||
3706 | void bdrv_cancel_in_flight(BlockDriverState *bs) | |
3707 | { | |
3708 | GLOBAL_STATE_CODE(); | |
3709 | if (!bs || !bs->drv) { | |
3710 | return; | |
3711 | } | |
3712 | ||
3713 | if (bs->drv->bdrv_cancel_in_flight) { | |
3714 | bs->drv->bdrv_cancel_in_flight(bs); | |
3715 | } | |
3716 | } | |
3717 | ||
3718 | int coroutine_fn | |
3719 | bdrv_co_preadv_snapshot(BdrvChild *child, int64_t offset, int64_t bytes, | |
3720 | QEMUIOVector *qiov, size_t qiov_offset) | |
3721 | { | |
3722 | BlockDriverState *bs = child->bs; | |
3723 | BlockDriver *drv = bs->drv; | |
3724 | int ret; | |
3725 | IO_CODE(); | |
3726 | assert_bdrv_graph_readable(); | |
3727 | ||
3728 | if (!drv) { | |
3729 | return -ENOMEDIUM; | |
3730 | } | |
3731 | ||
3732 | if (!drv->bdrv_co_preadv_snapshot) { | |
3733 | return -ENOTSUP; | |
3734 | } | |
3735 | ||
3736 | bdrv_inc_in_flight(bs); | |
3737 | ret = drv->bdrv_co_preadv_snapshot(bs, offset, bytes, qiov, qiov_offset); | |
3738 | bdrv_dec_in_flight(bs); | |
3739 | ||
3740 | return ret; | |
3741 | } | |
3742 | ||
3743 | int coroutine_fn | |
3744 | bdrv_co_snapshot_block_status(BlockDriverState *bs, | |
3745 | bool want_zero, int64_t offset, int64_t bytes, | |
3746 | int64_t *pnum, int64_t *map, | |
3747 | BlockDriverState **file) | |
3748 | { | |
3749 | BlockDriver *drv = bs->drv; | |
3750 | int ret; | |
3751 | IO_CODE(); | |
3752 | assert_bdrv_graph_readable(); | |
3753 | ||
3754 | if (!drv) { | |
3755 | return -ENOMEDIUM; | |
3756 | } | |
3757 | ||
3758 | if (!drv->bdrv_co_snapshot_block_status) { | |
3759 | return -ENOTSUP; | |
3760 | } | |
3761 | ||
3762 | bdrv_inc_in_flight(bs); | |
3763 | ret = drv->bdrv_co_snapshot_block_status(bs, want_zero, offset, bytes, | |
3764 | pnum, map, file); | |
3765 | bdrv_dec_in_flight(bs); | |
3766 | ||
3767 | return ret; | |
3768 | } | |
3769 | ||
3770 | int coroutine_fn | |
3771 | bdrv_co_pdiscard_snapshot(BlockDriverState *bs, int64_t offset, int64_t bytes) | |
3772 | { | |
3773 | BlockDriver *drv = bs->drv; | |
3774 | int ret; | |
3775 | IO_CODE(); | |
3776 | assert_bdrv_graph_readable(); | |
3777 | ||
3778 | if (!drv) { | |
3779 | return -ENOMEDIUM; | |
3780 | } | |
3781 | ||
3782 | if (!drv->bdrv_co_pdiscard_snapshot) { | |
3783 | return -ENOTSUP; | |
3784 | } | |
3785 | ||
3786 | bdrv_inc_in_flight(bs); | |
3787 | ret = drv->bdrv_co_pdiscard_snapshot(bs, offset, bytes); | |
3788 | bdrv_dec_in_flight(bs); | |
3789 | ||
3790 | return ret; | |
3791 | } |