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 "qemu/cutils.h" |
33 | #include "qapi/error.h" |
34 | #include "qemu/error-report.h" |
35 | #include "qemu/main-loop.h" |
36 | |
37 | #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ |
38 | |
39 | /* Maximum bounce buffer for copy-on-read and write zeroes, in bytes */ |
40 | #define MAX_BOUNCE_BUFFER (32768 << BDRV_SECTOR_BITS) |
41 | |
42 | static void bdrv_parent_cb_resize(BlockDriverState *bs); |
43 | static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, |
44 | int64_t offset, int bytes, BdrvRequestFlags flags); |
45 | |
46 | static void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore, |
47 | bool ignore_bds_parents) |
48 | { |
49 | BdrvChild *c, *next; |
50 | |
51 | QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) { |
52 | if (c == ignore || (ignore_bds_parents && c->role->parent_is_bds)) { |
53 | continue; |
54 | } |
55 | bdrv_parent_drained_begin_single(c, false); |
56 | } |
57 | } |
58 | |
59 | static void bdrv_parent_drained_end_single_no_poll(BdrvChild *c, |
60 | int *drained_end_counter) |
61 | { |
62 | assert(c->parent_quiesce_counter > 0); |
63 | c->parent_quiesce_counter--; |
64 | if (c->role->drained_end) { |
65 | c->role->drained_end(c, drained_end_counter); |
66 | } |
67 | } |
68 | |
69 | void bdrv_parent_drained_end_single(BdrvChild *c) |
70 | { |
71 | int drained_end_counter = 0; |
72 | bdrv_parent_drained_end_single_no_poll(c, &drained_end_counter); |
73 | BDRV_POLL_WHILE(c->bs, atomic_read(&drained_end_counter) > 0); |
74 | } |
75 | |
76 | static void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore, |
77 | bool ignore_bds_parents, |
78 | int *drained_end_counter) |
79 | { |
80 | BdrvChild *c; |
81 | |
82 | QLIST_FOREACH(c, &bs->parents, next_parent) { |
83 | if (c == ignore || (ignore_bds_parents && c->role->parent_is_bds)) { |
84 | continue; |
85 | } |
86 | bdrv_parent_drained_end_single_no_poll(c, drained_end_counter); |
87 | } |
88 | } |
89 | |
90 | static bool bdrv_parent_drained_poll_single(BdrvChild *c) |
91 | { |
92 | if (c->role->drained_poll) { |
93 | return c->role->drained_poll(c); |
94 | } |
95 | return false; |
96 | } |
97 | |
98 | static bool bdrv_parent_drained_poll(BlockDriverState *bs, BdrvChild *ignore, |
99 | bool ignore_bds_parents) |
100 | { |
101 | BdrvChild *c, *next; |
102 | bool busy = false; |
103 | |
104 | QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) { |
105 | if (c == ignore || (ignore_bds_parents && c->role->parent_is_bds)) { |
106 | continue; |
107 | } |
108 | busy |= bdrv_parent_drained_poll_single(c); |
109 | } |
110 | |
111 | return busy; |
112 | } |
113 | |
114 | void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll) |
115 | { |
116 | c->parent_quiesce_counter++; |
117 | if (c->role->drained_begin) { |
118 | c->role->drained_begin(c); |
119 | } |
120 | if (poll) { |
121 | BDRV_POLL_WHILE(c->bs, bdrv_parent_drained_poll_single(c)); |
122 | } |
123 | } |
124 | |
125 | static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src) |
126 | { |
127 | dst->opt_transfer = MAX(dst->opt_transfer, src->opt_transfer); |
128 | dst->max_transfer = MIN_NON_ZERO(dst->max_transfer, src->max_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 | } |
135 | |
136 | void bdrv_refresh_limits(BlockDriverState *bs, Error **errp) |
137 | { |
138 | BlockDriver *drv = bs->drv; |
139 | Error *local_err = NULL; |
140 | |
141 | memset(&bs->bl, 0, sizeof(bs->bl)); |
142 | |
143 | if (!drv) { |
144 | return; |
145 | } |
146 | |
147 | /* Default alignment based on whether driver has byte interface */ |
148 | bs->bl.request_alignment = (drv->bdrv_co_preadv || |
149 | drv->bdrv_aio_preadv || |
150 | drv->bdrv_co_preadv_part) ? 1 : 512; |
151 | |
152 | /* Take some limits from the children as a default */ |
153 | if (bs->file) { |
154 | bdrv_refresh_limits(bs->file->bs, &local_err); |
155 | if (local_err) { |
156 | error_propagate(errp, local_err); |
157 | return; |
158 | } |
159 | bdrv_merge_limits(&bs->bl, &bs->file->bs->bl); |
160 | } else { |
161 | bs->bl.min_mem_alignment = 512; |
162 | bs->bl.opt_mem_alignment = getpagesize(); |
163 | |
164 | /* Safe default since most protocols use readv()/writev()/etc */ |
165 | bs->bl.max_iov = IOV_MAX; |
166 | } |
167 | |
168 | if (bs->backing) { |
169 | bdrv_refresh_limits(bs->backing->bs, &local_err); |
170 | if (local_err) { |
171 | error_propagate(errp, local_err); |
172 | return; |
173 | } |
174 | bdrv_merge_limits(&bs->bl, &bs->backing->bs->bl); |
175 | } |
176 | |
177 | /* Then let the driver override it */ |
178 | if (drv->bdrv_refresh_limits) { |
179 | drv->bdrv_refresh_limits(bs, errp); |
180 | } |
181 | } |
182 | |
183 | /** |
184 | * The copy-on-read flag is actually a reference count so multiple users may |
185 | * use the feature without worrying about clobbering its previous state. |
186 | * Copy-on-read stays enabled until all users have called to disable it. |
187 | */ |
188 | void bdrv_enable_copy_on_read(BlockDriverState *bs) |
189 | { |
190 | atomic_inc(&bs->copy_on_read); |
191 | } |
192 | |
193 | void bdrv_disable_copy_on_read(BlockDriverState *bs) |
194 | { |
195 | int old = atomic_fetch_dec(&bs->copy_on_read); |
196 | assert(old >= 1); |
197 | } |
198 | |
199 | typedef struct { |
200 | Coroutine *co; |
201 | BlockDriverState *bs; |
202 | bool done; |
203 | bool begin; |
204 | bool recursive; |
205 | bool poll; |
206 | BdrvChild *parent; |
207 | bool ignore_bds_parents; |
208 | int *drained_end_counter; |
209 | } BdrvCoDrainData; |
210 | |
211 | static void coroutine_fn bdrv_drain_invoke_entry(void *opaque) |
212 | { |
213 | BdrvCoDrainData *data = opaque; |
214 | BlockDriverState *bs = data->bs; |
215 | |
216 | if (data->begin) { |
217 | bs->drv->bdrv_co_drain_begin(bs); |
218 | } else { |
219 | bs->drv->bdrv_co_drain_end(bs); |
220 | } |
221 | |
222 | /* Set data->done and decrement drained_end_counter before bdrv_wakeup() */ |
223 | atomic_mb_set(&data->done, true); |
224 | if (!data->begin) { |
225 | atomic_dec(data->drained_end_counter); |
226 | } |
227 | bdrv_dec_in_flight(bs); |
228 | |
229 | g_free(data); |
230 | } |
231 | |
232 | /* Recursively call BlockDriver.bdrv_co_drain_begin/end callbacks */ |
233 | static void bdrv_drain_invoke(BlockDriverState *bs, bool begin, |
234 | int *drained_end_counter) |
235 | { |
236 | BdrvCoDrainData *data; |
237 | |
238 | if (!bs->drv || (begin && !bs->drv->bdrv_co_drain_begin) || |
239 | (!begin && !bs->drv->bdrv_co_drain_end)) { |
240 | return; |
241 | } |
242 | |
243 | data = g_new(BdrvCoDrainData, 1); |
244 | *data = (BdrvCoDrainData) { |
245 | .bs = bs, |
246 | .done = false, |
247 | .begin = begin, |
248 | .drained_end_counter = drained_end_counter, |
249 | }; |
250 | |
251 | if (!begin) { |
252 | atomic_inc(drained_end_counter); |
253 | } |
254 | |
255 | /* Make sure the driver callback completes during the polling phase for |
256 | * drain_begin. */ |
257 | bdrv_inc_in_flight(bs); |
258 | data->co = qemu_coroutine_create(bdrv_drain_invoke_entry, data); |
259 | aio_co_schedule(bdrv_get_aio_context(bs), data->co); |
260 | } |
261 | |
262 | /* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */ |
263 | bool bdrv_drain_poll(BlockDriverState *bs, bool recursive, |
264 | BdrvChild *ignore_parent, bool ignore_bds_parents) |
265 | { |
266 | BdrvChild *child, *next; |
267 | |
268 | if (bdrv_parent_drained_poll(bs, ignore_parent, ignore_bds_parents)) { |
269 | return true; |
270 | } |
271 | |
272 | if (atomic_read(&bs->in_flight)) { |
273 | return true; |
274 | } |
275 | |
276 | if (recursive) { |
277 | assert(!ignore_bds_parents); |
278 | QLIST_FOREACH_SAFE(child, &bs->children, next, next) { |
279 | if (bdrv_drain_poll(child->bs, recursive, child, false)) { |
280 | return true; |
281 | } |
282 | } |
283 | } |
284 | |
285 | return false; |
286 | } |
287 | |
288 | static bool bdrv_drain_poll_top_level(BlockDriverState *bs, bool recursive, |
289 | BdrvChild *ignore_parent) |
290 | { |
291 | return bdrv_drain_poll(bs, recursive, ignore_parent, false); |
292 | } |
293 | |
294 | static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive, |
295 | BdrvChild *parent, bool ignore_bds_parents, |
296 | bool poll); |
297 | static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive, |
298 | BdrvChild *parent, bool ignore_bds_parents, |
299 | int *drained_end_counter); |
300 | |
301 | static void bdrv_co_drain_bh_cb(void *opaque) |
302 | { |
303 | BdrvCoDrainData *data = opaque; |
304 | Coroutine *co = data->co; |
305 | BlockDriverState *bs = data->bs; |
306 | |
307 | if (bs) { |
308 | AioContext *ctx = bdrv_get_aio_context(bs); |
309 | AioContext *co_ctx = qemu_coroutine_get_aio_context(co); |
310 | |
311 | /* |
312 | * When the coroutine yielded, the lock for its home context was |
313 | * released, so we need to re-acquire it here. If it explicitly |
314 | * acquired a different context, the lock is still held and we don't |
315 | * want to lock it a second time (or AIO_WAIT_WHILE() would hang). |
316 | */ |
317 | if (ctx == co_ctx) { |
318 | aio_context_acquire(ctx); |
319 | } |
320 | bdrv_dec_in_flight(bs); |
321 | if (data->begin) { |
322 | assert(!data->drained_end_counter); |
323 | bdrv_do_drained_begin(bs, data->recursive, data->parent, |
324 | data->ignore_bds_parents, data->poll); |
325 | } else { |
326 | assert(!data->poll); |
327 | bdrv_do_drained_end(bs, data->recursive, data->parent, |
328 | data->ignore_bds_parents, |
329 | data->drained_end_counter); |
330 | } |
331 | if (ctx == co_ctx) { |
332 | aio_context_release(ctx); |
333 | } |
334 | } else { |
335 | assert(data->begin); |
336 | bdrv_drain_all_begin(); |
337 | } |
338 | |
339 | data->done = true; |
340 | aio_co_wake(co); |
341 | } |
342 | |
343 | static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, |
344 | bool begin, bool recursive, |
345 | BdrvChild *parent, |
346 | bool ignore_bds_parents, |
347 | bool poll, |
348 | int *drained_end_counter) |
349 | { |
350 | BdrvCoDrainData data; |
351 | |
352 | /* Calling bdrv_drain() from a BH ensures the current coroutine yields and |
353 | * other coroutines run if they were queued by aio_co_enter(). */ |
354 | |
355 | assert(qemu_in_coroutine()); |
356 | data = (BdrvCoDrainData) { |
357 | .co = qemu_coroutine_self(), |
358 | .bs = bs, |
359 | .done = false, |
360 | .begin = begin, |
361 | .recursive = recursive, |
362 | .parent = parent, |
363 | .ignore_bds_parents = ignore_bds_parents, |
364 | .poll = poll, |
365 | .drained_end_counter = drained_end_counter, |
366 | }; |
367 | |
368 | if (bs) { |
369 | bdrv_inc_in_flight(bs); |
370 | } |
371 | aio_bh_schedule_oneshot(bdrv_get_aio_context(bs), |
372 | bdrv_co_drain_bh_cb, &data); |
373 | |
374 | qemu_coroutine_yield(); |
375 | /* If we are resumed from some other event (such as an aio completion or a |
376 | * timer callback), it is a bug in the caller that should be fixed. */ |
377 | assert(data.done); |
378 | } |
379 | |
380 | void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, |
381 | BdrvChild *parent, bool ignore_bds_parents) |
382 | { |
383 | assert(!qemu_in_coroutine()); |
384 | |
385 | /* Stop things in parent-to-child order */ |
386 | if (atomic_fetch_inc(&bs->quiesce_counter) == 0) { |
387 | aio_disable_external(bdrv_get_aio_context(bs)); |
388 | } |
389 | |
390 | bdrv_parent_drained_begin(bs, parent, ignore_bds_parents); |
391 | bdrv_drain_invoke(bs, true, NULL); |
392 | } |
393 | |
394 | static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive, |
395 | BdrvChild *parent, bool ignore_bds_parents, |
396 | bool poll) |
397 | { |
398 | BdrvChild *child, *next; |
399 | |
400 | if (qemu_in_coroutine()) { |
401 | bdrv_co_yield_to_drain(bs, true, recursive, parent, ignore_bds_parents, |
402 | poll, NULL); |
403 | return; |
404 | } |
405 | |
406 | bdrv_do_drained_begin_quiesce(bs, parent, ignore_bds_parents); |
407 | |
408 | if (recursive) { |
409 | assert(!ignore_bds_parents); |
410 | bs->recursive_quiesce_counter++; |
411 | QLIST_FOREACH_SAFE(child, &bs->children, next, next) { |
412 | bdrv_do_drained_begin(child->bs, true, child, ignore_bds_parents, |
413 | false); |
414 | } |
415 | } |
416 | |
417 | /* |
418 | * Wait for drained requests to finish. |
419 | * |
420 | * Calling BDRV_POLL_WHILE() only once for the top-level node is okay: The |
421 | * call is needed so things in this AioContext can make progress even |
422 | * though we don't return to the main AioContext loop - this automatically |
423 | * includes other nodes in the same AioContext and therefore all child |
424 | * nodes. |
425 | */ |
426 | if (poll) { |
427 | assert(!ignore_bds_parents); |
428 | BDRV_POLL_WHILE(bs, bdrv_drain_poll_top_level(bs, recursive, parent)); |
429 | } |
430 | } |
431 | |
432 | void bdrv_drained_begin(BlockDriverState *bs) |
433 | { |
434 | bdrv_do_drained_begin(bs, false, NULL, false, true); |
435 | } |
436 | |
437 | void bdrv_subtree_drained_begin(BlockDriverState *bs) |
438 | { |
439 | bdrv_do_drained_begin(bs, true, NULL, false, true); |
440 | } |
441 | |
442 | /** |
443 | * This function does not poll, nor must any of its recursively called |
444 | * functions. The *drained_end_counter pointee will be incremented |
445 | * once for every background operation scheduled, and decremented once |
446 | * the operation settles. Therefore, the pointer must remain valid |
447 | * until the pointee reaches 0. That implies that whoever sets up the |
448 | * pointee has to poll until it is 0. |
449 | * |
450 | * We use atomic operations to access *drained_end_counter, because |
451 | * (1) when called from bdrv_set_aio_context_ignore(), the subgraph of |
452 | * @bs may contain nodes in different AioContexts, |
453 | * (2) bdrv_drain_all_end() uses the same counter for all nodes, |
454 | * regardless of which AioContext they are in. |
455 | */ |
456 | static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive, |
457 | BdrvChild *parent, bool ignore_bds_parents, |
458 | int *drained_end_counter) |
459 | { |
460 | BdrvChild *child; |
461 | int old_quiesce_counter; |
462 | |
463 | assert(drained_end_counter != NULL); |
464 | |
465 | if (qemu_in_coroutine()) { |
466 | bdrv_co_yield_to_drain(bs, false, recursive, parent, ignore_bds_parents, |
467 | false, drained_end_counter); |
468 | return; |
469 | } |
470 | assert(bs->quiesce_counter > 0); |
471 | |
472 | /* Re-enable things in child-to-parent order */ |
473 | bdrv_drain_invoke(bs, false, drained_end_counter); |
474 | bdrv_parent_drained_end(bs, parent, ignore_bds_parents, |
475 | drained_end_counter); |
476 | |
477 | old_quiesce_counter = atomic_fetch_dec(&bs->quiesce_counter); |
478 | if (old_quiesce_counter == 1) { |
479 | aio_enable_external(bdrv_get_aio_context(bs)); |
480 | } |
481 | |
482 | if (recursive) { |
483 | assert(!ignore_bds_parents); |
484 | bs->recursive_quiesce_counter--; |
485 | QLIST_FOREACH(child, &bs->children, next) { |
486 | bdrv_do_drained_end(child->bs, true, child, ignore_bds_parents, |
487 | drained_end_counter); |
488 | } |
489 | } |
490 | } |
491 | |
492 | void bdrv_drained_end(BlockDriverState *bs) |
493 | { |
494 | int drained_end_counter = 0; |
495 | bdrv_do_drained_end(bs, false, NULL, false, &drained_end_counter); |
496 | BDRV_POLL_WHILE(bs, atomic_read(&drained_end_counter) > 0); |
497 | } |
498 | |
499 | void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter) |
500 | { |
501 | bdrv_do_drained_end(bs, false, NULL, false, drained_end_counter); |
502 | } |
503 | |
504 | void bdrv_subtree_drained_end(BlockDriverState *bs) |
505 | { |
506 | int drained_end_counter = 0; |
507 | bdrv_do_drained_end(bs, true, NULL, false, &drained_end_counter); |
508 | BDRV_POLL_WHILE(bs, atomic_read(&drained_end_counter) > 0); |
509 | } |
510 | |
511 | void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent) |
512 | { |
513 | int i; |
514 | |
515 | for (i = 0; i < new_parent->recursive_quiesce_counter; i++) { |
516 | bdrv_do_drained_begin(child->bs, true, child, false, true); |
517 | } |
518 | } |
519 | |
520 | void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent) |
521 | { |
522 | int drained_end_counter = 0; |
523 | int i; |
524 | |
525 | for (i = 0; i < old_parent->recursive_quiesce_counter; i++) { |
526 | bdrv_do_drained_end(child->bs, true, child, false, |
527 | &drained_end_counter); |
528 | } |
529 | |
530 | BDRV_POLL_WHILE(child->bs, atomic_read(&drained_end_counter) > 0); |
531 | } |
532 | |
533 | /* |
534 | * Wait for pending requests to complete on a single BlockDriverState subtree, |
535 | * and suspend block driver's internal I/O until next request arrives. |
536 | * |
537 | * Note that unlike bdrv_drain_all(), the caller must hold the BlockDriverState |
538 | * AioContext. |
539 | */ |
540 | void coroutine_fn bdrv_co_drain(BlockDriverState *bs) |
541 | { |
542 | assert(qemu_in_coroutine()); |
543 | bdrv_drained_begin(bs); |
544 | bdrv_drained_end(bs); |
545 | } |
546 | |
547 | void bdrv_drain(BlockDriverState *bs) |
548 | { |
549 | bdrv_drained_begin(bs); |
550 | bdrv_drained_end(bs); |
551 | } |
552 | |
553 | static void bdrv_drain_assert_idle(BlockDriverState *bs) |
554 | { |
555 | BdrvChild *child, *next; |
556 | |
557 | assert(atomic_read(&bs->in_flight) == 0); |
558 | QLIST_FOREACH_SAFE(child, &bs->children, next, next) { |
559 | bdrv_drain_assert_idle(child->bs); |
560 | } |
561 | } |
562 | |
563 | unsigned int bdrv_drain_all_count = 0; |
564 | |
565 | static bool bdrv_drain_all_poll(void) |
566 | { |
567 | BlockDriverState *bs = NULL; |
568 | bool result = false; |
569 | |
570 | /* bdrv_drain_poll() can't make changes to the graph and we are holding the |
571 | * main AioContext lock, so iterating bdrv_next_all_states() is safe. */ |
572 | while ((bs = bdrv_next_all_states(bs))) { |
573 | AioContext *aio_context = bdrv_get_aio_context(bs); |
574 | aio_context_acquire(aio_context); |
575 | result |= bdrv_drain_poll(bs, false, NULL, true); |
576 | aio_context_release(aio_context); |
577 | } |
578 | |
579 | return result; |
580 | } |
581 | |
582 | /* |
583 | * Wait for pending requests to complete across all BlockDriverStates |
584 | * |
585 | * This function does not flush data to disk, use bdrv_flush_all() for that |
586 | * after calling this function. |
587 | * |
588 | * This pauses all block jobs and disables external clients. It must |
589 | * be paired with bdrv_drain_all_end(). |
590 | * |
591 | * NOTE: no new block jobs or BlockDriverStates can be created between |
592 | * the bdrv_drain_all_begin() and bdrv_drain_all_end() calls. |
593 | */ |
594 | void bdrv_drain_all_begin(void) |
595 | { |
596 | BlockDriverState *bs = NULL; |
597 | |
598 | if (qemu_in_coroutine()) { |
599 | bdrv_co_yield_to_drain(NULL, true, false, NULL, true, true, NULL); |
600 | return; |
601 | } |
602 | |
603 | /* AIO_WAIT_WHILE() with a NULL context can only be called from the main |
604 | * loop AioContext, so make sure we're in the main context. */ |
605 | assert(qemu_get_current_aio_context() == qemu_get_aio_context()); |
606 | assert(bdrv_drain_all_count < INT_MAX); |
607 | bdrv_drain_all_count++; |
608 | |
609 | /* Quiesce all nodes, without polling in-flight requests yet. The graph |
610 | * cannot change during this loop. */ |
611 | while ((bs = bdrv_next_all_states(bs))) { |
612 | AioContext *aio_context = bdrv_get_aio_context(bs); |
613 | |
614 | aio_context_acquire(aio_context); |
615 | bdrv_do_drained_begin(bs, false, NULL, true, false); |
616 | aio_context_release(aio_context); |
617 | } |
618 | |
619 | /* Now poll the in-flight requests */ |
620 | AIO_WAIT_WHILE(NULL, bdrv_drain_all_poll()); |
621 | |
622 | while ((bs = bdrv_next_all_states(bs))) { |
623 | bdrv_drain_assert_idle(bs); |
624 | } |
625 | } |
626 | |
627 | void bdrv_drain_all_end(void) |
628 | { |
629 | BlockDriverState *bs = NULL; |
630 | int drained_end_counter = 0; |
631 | |
632 | while ((bs = bdrv_next_all_states(bs))) { |
633 | AioContext *aio_context = bdrv_get_aio_context(bs); |
634 | |
635 | aio_context_acquire(aio_context); |
636 | bdrv_do_drained_end(bs, false, NULL, true, &drained_end_counter); |
637 | aio_context_release(aio_context); |
638 | } |
639 | |
640 | assert(qemu_get_current_aio_context() == qemu_get_aio_context()); |
641 | AIO_WAIT_WHILE(NULL, atomic_read(&drained_end_counter) > 0); |
642 | |
643 | assert(bdrv_drain_all_count > 0); |
644 | bdrv_drain_all_count--; |
645 | } |
646 | |
647 | void bdrv_drain_all(void) |
648 | { |
649 | bdrv_drain_all_begin(); |
650 | bdrv_drain_all_end(); |
651 | } |
652 | |
653 | /** |
654 | * Remove an active request from the tracked requests list |
655 | * |
656 | * This function should be called when a tracked request is completing. |
657 | */ |
658 | static void tracked_request_end(BdrvTrackedRequest *req) |
659 | { |
660 | if (req->serialising) { |
661 | atomic_dec(&req->bs->serialising_in_flight); |
662 | } |
663 | |
664 | qemu_co_mutex_lock(&req->bs->reqs_lock); |
665 | QLIST_REMOVE(req, list); |
666 | qemu_co_queue_restart_all(&req->wait_queue); |
667 | qemu_co_mutex_unlock(&req->bs->reqs_lock); |
668 | } |
669 | |
670 | /** |
671 | * Add an active request to the tracked requests list |
672 | */ |
673 | static void tracked_request_begin(BdrvTrackedRequest *req, |
674 | BlockDriverState *bs, |
675 | int64_t offset, |
676 | uint64_t bytes, |
677 | enum BdrvTrackedRequestType type) |
678 | { |
679 | assert(bytes <= INT64_MAX && offset <= INT64_MAX - bytes); |
680 | |
681 | *req = (BdrvTrackedRequest){ |
682 | .bs = bs, |
683 | .offset = offset, |
684 | .bytes = bytes, |
685 | .type = type, |
686 | .co = qemu_coroutine_self(), |
687 | .serialising = false, |
688 | .overlap_offset = offset, |
689 | .overlap_bytes = bytes, |
690 | }; |
691 | |
692 | qemu_co_queue_init(&req->wait_queue); |
693 | |
694 | qemu_co_mutex_lock(&bs->reqs_lock); |
695 | QLIST_INSERT_HEAD(&bs->tracked_requests, req, list); |
696 | qemu_co_mutex_unlock(&bs->reqs_lock); |
697 | } |
698 | |
699 | static void mark_request_serialising(BdrvTrackedRequest *req, uint64_t align) |
700 | { |
701 | int64_t overlap_offset = req->offset & ~(align - 1); |
702 | uint64_t overlap_bytes = ROUND_UP(req->offset + req->bytes, align) |
703 | - overlap_offset; |
704 | |
705 | if (!req->serialising) { |
706 | atomic_inc(&req->bs->serialising_in_flight); |
707 | req->serialising = true; |
708 | } |
709 | |
710 | req->overlap_offset = MIN(req->overlap_offset, overlap_offset); |
711 | req->overlap_bytes = MAX(req->overlap_bytes, overlap_bytes); |
712 | } |
713 | |
714 | static bool is_request_serialising_and_aligned(BdrvTrackedRequest *req) |
715 | { |
716 | /* |
717 | * If the request is serialising, overlap_offset and overlap_bytes are set, |
718 | * so we can check if the request is aligned. Otherwise, don't care and |
719 | * return false. |
720 | */ |
721 | |
722 | return req->serialising && (req->offset == req->overlap_offset) && |
723 | (req->bytes == req->overlap_bytes); |
724 | } |
725 | |
726 | /** |
727 | * Round a region to cluster boundaries |
728 | */ |
729 | void bdrv_round_to_clusters(BlockDriverState *bs, |
730 | int64_t offset, int64_t bytes, |
731 | int64_t *cluster_offset, |
732 | int64_t *cluster_bytes) |
733 | { |
734 | BlockDriverInfo bdi; |
735 | |
736 | if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) { |
737 | *cluster_offset = offset; |
738 | *cluster_bytes = bytes; |
739 | } else { |
740 | int64_t c = bdi.cluster_size; |
741 | *cluster_offset = QEMU_ALIGN_DOWN(offset, c); |
742 | *cluster_bytes = QEMU_ALIGN_UP(offset - *cluster_offset + bytes, c); |
743 | } |
744 | } |
745 | |
746 | static int bdrv_get_cluster_size(BlockDriverState *bs) |
747 | { |
748 | BlockDriverInfo bdi; |
749 | int ret; |
750 | |
751 | ret = bdrv_get_info(bs, &bdi); |
752 | if (ret < 0 || bdi.cluster_size == 0) { |
753 | return bs->bl.request_alignment; |
754 | } else { |
755 | return bdi.cluster_size; |
756 | } |
757 | } |
758 | |
759 | static bool tracked_request_overlaps(BdrvTrackedRequest *req, |
760 | int64_t offset, uint64_t bytes) |
761 | { |
762 | /* aaaa bbbb */ |
763 | if (offset >= req->overlap_offset + req->overlap_bytes) { |
764 | return false; |
765 | } |
766 | /* bbbb aaaa */ |
767 | if (req->overlap_offset >= offset + bytes) { |
768 | return false; |
769 | } |
770 | return true; |
771 | } |
772 | |
773 | void bdrv_inc_in_flight(BlockDriverState *bs) |
774 | { |
775 | atomic_inc(&bs->in_flight); |
776 | } |
777 | |
778 | void bdrv_wakeup(BlockDriverState *bs) |
779 | { |
780 | aio_wait_kick(); |
781 | } |
782 | |
783 | void bdrv_dec_in_flight(BlockDriverState *bs) |
784 | { |
785 | atomic_dec(&bs->in_flight); |
786 | bdrv_wakeup(bs); |
787 | } |
788 | |
789 | static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self) |
790 | { |
791 | BlockDriverState *bs = self->bs; |
792 | BdrvTrackedRequest *req; |
793 | bool retry; |
794 | bool waited = false; |
795 | |
796 | if (!atomic_read(&bs->serialising_in_flight)) { |
797 | return false; |
798 | } |
799 | |
800 | do { |
801 | retry = false; |
802 | qemu_co_mutex_lock(&bs->reqs_lock); |
803 | QLIST_FOREACH(req, &bs->tracked_requests, list) { |
804 | if (req == self || (!req->serialising && !self->serialising)) { |
805 | continue; |
806 | } |
807 | if (tracked_request_overlaps(req, self->overlap_offset, |
808 | self->overlap_bytes)) |
809 | { |
810 | /* Hitting this means there was a reentrant request, for |
811 | * example, a block driver issuing nested requests. This must |
812 | * never happen since it means deadlock. |
813 | */ |
814 | assert(qemu_coroutine_self() != req->co); |
815 | |
816 | /* If the request is already (indirectly) waiting for us, or |
817 | * will wait for us as soon as it wakes up, then just go on |
818 | * (instead of producing a deadlock in the former case). */ |
819 | if (!req->waiting_for) { |
820 | self->waiting_for = req; |
821 | qemu_co_queue_wait(&req->wait_queue, &bs->reqs_lock); |
822 | self->waiting_for = NULL; |
823 | retry = true; |
824 | waited = true; |
825 | break; |
826 | } |
827 | } |
828 | } |
829 | qemu_co_mutex_unlock(&bs->reqs_lock); |
830 | } while (retry); |
831 | |
832 | return waited; |
833 | } |
834 | |
835 | static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset, |
836 | size_t size) |
837 | { |
838 | if (size > BDRV_REQUEST_MAX_BYTES) { |
839 | return -EIO; |
840 | } |
841 | |
842 | if (!bdrv_is_inserted(bs)) { |
843 | return -ENOMEDIUM; |
844 | } |
845 | |
846 | if (offset < 0) { |
847 | return -EIO; |
848 | } |
849 | |
850 | return 0; |
851 | } |
852 | |
853 | typedef struct RwCo { |
854 | BdrvChild *child; |
855 | int64_t offset; |
856 | QEMUIOVector *qiov; |
857 | bool is_write; |
858 | int ret; |
859 | BdrvRequestFlags flags; |
860 | } RwCo; |
861 | |
862 | static void coroutine_fn bdrv_rw_co_entry(void *opaque) |
863 | { |
864 | RwCo *rwco = opaque; |
865 | |
866 | if (!rwco->is_write) { |
867 | rwco->ret = bdrv_co_preadv(rwco->child, rwco->offset, |
868 | rwco->qiov->size, rwco->qiov, |
869 | rwco->flags); |
870 | } else { |
871 | rwco->ret = bdrv_co_pwritev(rwco->child, rwco->offset, |
872 | rwco->qiov->size, rwco->qiov, |
873 | rwco->flags); |
874 | } |
875 | aio_wait_kick(); |
876 | } |
877 | |
878 | /* |
879 | * Process a vectored synchronous request using coroutines |
880 | */ |
881 | static int bdrv_prwv_co(BdrvChild *child, int64_t offset, |
882 | QEMUIOVector *qiov, bool is_write, |
883 | BdrvRequestFlags flags) |
884 | { |
885 | Coroutine *co; |
886 | RwCo rwco = { |
887 | .child = child, |
888 | .offset = offset, |
889 | .qiov = qiov, |
890 | .is_write = is_write, |
891 | .ret = NOT_DONE, |
892 | .flags = flags, |
893 | }; |
894 | |
895 | if (qemu_in_coroutine()) { |
896 | /* Fast-path if already in coroutine context */ |
897 | bdrv_rw_co_entry(&rwco); |
898 | } else { |
899 | co = qemu_coroutine_create(bdrv_rw_co_entry, &rwco); |
900 | bdrv_coroutine_enter(child->bs, co); |
901 | BDRV_POLL_WHILE(child->bs, rwco.ret == NOT_DONE); |
902 | } |
903 | return rwco.ret; |
904 | } |
905 | |
906 | int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset, |
907 | int bytes, BdrvRequestFlags flags) |
908 | { |
909 | QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, bytes); |
910 | |
911 | return bdrv_prwv_co(child, offset, &qiov, true, |
912 | BDRV_REQ_ZERO_WRITE | flags); |
913 | } |
914 | |
915 | /* |
916 | * Completely zero out a block device with the help of bdrv_pwrite_zeroes. |
917 | * The operation is sped up by checking the block status and only writing |
918 | * zeroes to the device if they currently do not return zeroes. Optional |
919 | * flags are passed through to bdrv_pwrite_zeroes (e.g. BDRV_REQ_MAY_UNMAP, |
920 | * BDRV_REQ_FUA). |
921 | * |
922 | * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). |
923 | */ |
924 | int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags) |
925 | { |
926 | int ret; |
927 | int64_t target_size, bytes, offset = 0; |
928 | BlockDriverState *bs = child->bs; |
929 | |
930 | target_size = bdrv_getlength(bs); |
931 | if (target_size < 0) { |
932 | return target_size; |
933 | } |
934 | |
935 | for (;;) { |
936 | bytes = MIN(target_size - offset, BDRV_REQUEST_MAX_BYTES); |
937 | if (bytes <= 0) { |
938 | return 0; |
939 | } |
940 | ret = bdrv_block_status(bs, offset, bytes, &bytes, NULL, NULL); |
941 | if (ret < 0) { |
942 | return ret; |
943 | } |
944 | if (ret & BDRV_BLOCK_ZERO) { |
945 | offset += bytes; |
946 | continue; |
947 | } |
948 | ret = bdrv_pwrite_zeroes(child, offset, bytes, flags); |
949 | if (ret < 0) { |
950 | return ret; |
951 | } |
952 | offset += bytes; |
953 | } |
954 | } |
955 | |
956 | int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov) |
957 | { |
958 | int ret; |
959 | |
960 | ret = bdrv_prwv_co(child, offset, qiov, false, 0); |
961 | if (ret < 0) { |
962 | return ret; |
963 | } |
964 | |
965 | return qiov->size; |
966 | } |
967 | |
968 | /* See bdrv_pwrite() for the return codes */ |
969 | int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes) |
970 | { |
971 | QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); |
972 | |
973 | if (bytes < 0) { |
974 | return -EINVAL; |
975 | } |
976 | |
977 | return bdrv_preadv(child, offset, &qiov); |
978 | } |
979 | |
980 | int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov) |
981 | { |
982 | int ret; |
983 | |
984 | ret = bdrv_prwv_co(child, offset, qiov, true, 0); |
985 | if (ret < 0) { |
986 | return ret; |
987 | } |
988 | |
989 | return qiov->size; |
990 | } |
991 | |
992 | /* Return no. of bytes on success or < 0 on error. Important errors are: |
993 | -EIO generic I/O error (may happen for all errors) |
994 | -ENOMEDIUM No media inserted. |
995 | -EINVAL Invalid offset or number of bytes |
996 | -EACCES Trying to write a read-only device |
997 | */ |
998 | int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes) |
999 | { |
1000 | QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); |
1001 | |
1002 | if (bytes < 0) { |
1003 | return -EINVAL; |
1004 | } |
1005 | |
1006 | return bdrv_pwritev(child, offset, &qiov); |
1007 | } |
1008 | |
1009 | /* |
1010 | * Writes to the file and ensures that no writes are reordered across this |
1011 | * request (acts as a barrier) |
1012 | * |
1013 | * Returns 0 on success, -errno in error cases. |
1014 | */ |
1015 | int bdrv_pwrite_sync(BdrvChild *child, int64_t offset, |
1016 | const void *buf, int count) |
1017 | { |
1018 | int ret; |
1019 | |
1020 | ret = bdrv_pwrite(child, offset, buf, count); |
1021 | if (ret < 0) { |
1022 | return ret; |
1023 | } |
1024 | |
1025 | ret = bdrv_flush(child->bs); |
1026 | if (ret < 0) { |
1027 | return ret; |
1028 | } |
1029 | |
1030 | return 0; |
1031 | } |
1032 | |
1033 | typedef struct CoroutineIOCompletion { |
1034 | Coroutine *coroutine; |
1035 | int ret; |
1036 | } CoroutineIOCompletion; |
1037 | |
1038 | static void bdrv_co_io_em_complete(void *opaque, int ret) |
1039 | { |
1040 | CoroutineIOCompletion *co = opaque; |
1041 | |
1042 | co->ret = ret; |
1043 | aio_co_wake(co->coroutine); |
1044 | } |
1045 | |
1046 | static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs, |
1047 | uint64_t offset, uint64_t bytes, |
1048 | QEMUIOVector *qiov, |
1049 | size_t qiov_offset, int flags) |
1050 | { |
1051 | BlockDriver *drv = bs->drv; |
1052 | int64_t sector_num; |
1053 | unsigned int nb_sectors; |
1054 | QEMUIOVector local_qiov; |
1055 | int ret; |
1056 | |
1057 | assert(!(flags & ~BDRV_REQ_MASK)); |
1058 | assert(!(flags & BDRV_REQ_NO_FALLBACK)); |
1059 | |
1060 | if (!drv) { |
1061 | return -ENOMEDIUM; |
1062 | } |
1063 | |
1064 | if (drv->bdrv_co_preadv_part) { |
1065 | return drv->bdrv_co_preadv_part(bs, offset, bytes, qiov, qiov_offset, |
1066 | flags); |
1067 | } |
1068 | |
1069 | if (qiov_offset > 0 || bytes != qiov->size) { |
1070 | qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes); |
1071 | qiov = &local_qiov; |
1072 | } |
1073 | |
1074 | if (drv->bdrv_co_preadv) { |
1075 | ret = drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags); |
1076 | goto out; |
1077 | } |
1078 | |
1079 | if (drv->bdrv_aio_preadv) { |
1080 | BlockAIOCB *acb; |
1081 | CoroutineIOCompletion co = { |
1082 | .coroutine = qemu_coroutine_self(), |
1083 | }; |
1084 | |
1085 | acb = drv->bdrv_aio_preadv(bs, offset, bytes, qiov, flags, |
1086 | bdrv_co_io_em_complete, &co); |
1087 | if (acb == NULL) { |
1088 | ret = -EIO; |
1089 | goto out; |
1090 | } else { |
1091 | qemu_coroutine_yield(); |
1092 | ret = co.ret; |
1093 | goto out; |
1094 | } |
1095 | } |
1096 | |
1097 | sector_num = offset >> BDRV_SECTOR_BITS; |
1098 | nb_sectors = bytes >> BDRV_SECTOR_BITS; |
1099 | |
1100 | assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); |
1101 | assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); |
1102 | assert(bytes <= BDRV_REQUEST_MAX_BYTES); |
1103 | assert(drv->bdrv_co_readv); |
1104 | |
1105 | ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); |
1106 | |
1107 | out: |
1108 | if (qiov == &local_qiov) { |
1109 | qemu_iovec_destroy(&local_qiov); |
1110 | } |
1111 | |
1112 | return ret; |
1113 | } |
1114 | |
1115 | static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs, |
1116 | uint64_t offset, uint64_t bytes, |
1117 | QEMUIOVector *qiov, |
1118 | size_t qiov_offset, int flags) |
1119 | { |
1120 | BlockDriver *drv = bs->drv; |
1121 | int64_t sector_num; |
1122 | unsigned int nb_sectors; |
1123 | QEMUIOVector local_qiov; |
1124 | int ret; |
1125 | |
1126 | assert(!(flags & ~BDRV_REQ_MASK)); |
1127 | assert(!(flags & BDRV_REQ_NO_FALLBACK)); |
1128 | |
1129 | if (!drv) { |
1130 | return -ENOMEDIUM; |
1131 | } |
1132 | |
1133 | if (drv->bdrv_co_pwritev_part) { |
1134 | ret = drv->bdrv_co_pwritev_part(bs, offset, bytes, qiov, qiov_offset, |
1135 | flags & bs->supported_write_flags); |
1136 | flags &= ~bs->supported_write_flags; |
1137 | goto emulate_flags; |
1138 | } |
1139 | |
1140 | if (qiov_offset > 0 || bytes != qiov->size) { |
1141 | qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes); |
1142 | qiov = &local_qiov; |
1143 | } |
1144 | |
1145 | if (drv->bdrv_co_pwritev) { |
1146 | ret = drv->bdrv_co_pwritev(bs, offset, bytes, qiov, |
1147 | flags & bs->supported_write_flags); |
1148 | flags &= ~bs->supported_write_flags; |
1149 | goto emulate_flags; |
1150 | } |
1151 | |
1152 | if (drv->bdrv_aio_pwritev) { |
1153 | BlockAIOCB *acb; |
1154 | CoroutineIOCompletion co = { |
1155 | .coroutine = qemu_coroutine_self(), |
1156 | }; |
1157 | |
1158 | acb = drv->bdrv_aio_pwritev(bs, offset, bytes, qiov, |
1159 | flags & bs->supported_write_flags, |
1160 | bdrv_co_io_em_complete, &co); |
1161 | flags &= ~bs->supported_write_flags; |
1162 | if (acb == NULL) { |
1163 | ret = -EIO; |
1164 | } else { |
1165 | qemu_coroutine_yield(); |
1166 | ret = co.ret; |
1167 | } |
1168 | goto emulate_flags; |
1169 | } |
1170 | |
1171 | sector_num = offset >> BDRV_SECTOR_BITS; |
1172 | nb_sectors = bytes >> BDRV_SECTOR_BITS; |
1173 | |
1174 | assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); |
1175 | assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); |
1176 | assert(bytes <= BDRV_REQUEST_MAX_BYTES); |
1177 | |
1178 | assert(drv->bdrv_co_writev); |
1179 | ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov, |
1180 | flags & bs->supported_write_flags); |
1181 | flags &= ~bs->supported_write_flags; |
1182 | |
1183 | emulate_flags: |
1184 | if (ret == 0 && (flags & BDRV_REQ_FUA)) { |
1185 | ret = bdrv_co_flush(bs); |
1186 | } |
1187 | |
1188 | if (qiov == &local_qiov) { |
1189 | qemu_iovec_destroy(&local_qiov); |
1190 | } |
1191 | |
1192 | return ret; |
1193 | } |
1194 | |
1195 | static int coroutine_fn |
1196 | bdrv_driver_pwritev_compressed(BlockDriverState *bs, uint64_t offset, |
1197 | uint64_t bytes, QEMUIOVector *qiov, |
1198 | size_t qiov_offset) |
1199 | { |
1200 | BlockDriver *drv = bs->drv; |
1201 | QEMUIOVector local_qiov; |
1202 | int ret; |
1203 | |
1204 | if (!drv) { |
1205 | return -ENOMEDIUM; |
1206 | } |
1207 | |
1208 | if (!block_driver_can_compress(drv)) { |
1209 | return -ENOTSUP; |
1210 | } |
1211 | |
1212 | if (drv->bdrv_co_pwritev_compressed_part) { |
1213 | return drv->bdrv_co_pwritev_compressed_part(bs, offset, bytes, |
1214 | qiov, qiov_offset); |
1215 | } |
1216 | |
1217 | if (qiov_offset == 0) { |
1218 | return drv->bdrv_co_pwritev_compressed(bs, offset, bytes, qiov); |
1219 | } |
1220 | |
1221 | qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes); |
1222 | ret = drv->bdrv_co_pwritev_compressed(bs, offset, bytes, &local_qiov); |
1223 | qemu_iovec_destroy(&local_qiov); |
1224 | |
1225 | return ret; |
1226 | } |
1227 | |
1228 | static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child, |
1229 | int64_t offset, unsigned int bytes, QEMUIOVector *qiov, |
1230 | size_t qiov_offset, int flags) |
1231 | { |
1232 | BlockDriverState *bs = child->bs; |
1233 | |
1234 | /* Perform I/O through a temporary buffer so that users who scribble over |
1235 | * their read buffer while the operation is in progress do not end up |
1236 | * modifying the image file. This is critical for zero-copy guest I/O |
1237 | * where anything might happen inside guest memory. |
1238 | */ |
1239 | void *bounce_buffer = NULL; |
1240 | |
1241 | BlockDriver *drv = bs->drv; |
1242 | int64_t cluster_offset; |
1243 | int64_t cluster_bytes; |
1244 | size_t skip_bytes; |
1245 | int ret; |
1246 | int max_transfer = MIN_NON_ZERO(bs->bl.max_transfer, |
1247 | BDRV_REQUEST_MAX_BYTES); |
1248 | unsigned int progress = 0; |
1249 | |
1250 | if (!drv) { |
1251 | return -ENOMEDIUM; |
1252 | } |
1253 | |
1254 | /* FIXME We cannot require callers to have write permissions when all they |
1255 | * are doing is a read request. If we did things right, write permissions |
1256 | * would be obtained anyway, but internally by the copy-on-read code. As |
1257 | * long as it is implemented here rather than in a separate filter driver, |
1258 | * the copy-on-read code doesn't have its own BdrvChild, however, for which |
1259 | * it could request permissions. Therefore we have to bypass the permission |
1260 | * system for the moment. */ |
1261 | // assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE)); |
1262 | |
1263 | /* Cover entire cluster so no additional backing file I/O is required when |
1264 | * allocating cluster in the image file. Note that this value may exceed |
1265 | * BDRV_REQUEST_MAX_BYTES (even when the original read did not), which |
1266 | * is one reason we loop rather than doing it all at once. |
1267 | */ |
1268 | bdrv_round_to_clusters(bs, offset, bytes, &cluster_offset, &cluster_bytes); |
1269 | skip_bytes = offset - cluster_offset; |
1270 | |
1271 | trace_bdrv_co_do_copy_on_readv(bs, offset, bytes, |
1272 | cluster_offset, cluster_bytes); |
1273 | |
1274 | while (cluster_bytes) { |
1275 | int64_t pnum; |
1276 | |
1277 | ret = bdrv_is_allocated(bs, cluster_offset, |
1278 | MIN(cluster_bytes, max_transfer), &pnum); |
1279 | if (ret < 0) { |
1280 | /* Safe to treat errors in querying allocation as if |
1281 | * unallocated; we'll probably fail again soon on the |
1282 | * read, but at least that will set a decent errno. |
1283 | */ |
1284 | pnum = MIN(cluster_bytes, max_transfer); |
1285 | } |
1286 | |
1287 | /* Stop at EOF if the image ends in the middle of the cluster */ |
1288 | if (ret == 0 && pnum == 0) { |
1289 | assert(progress >= bytes); |
1290 | break; |
1291 | } |
1292 | |
1293 | assert(skip_bytes < pnum); |
1294 | |
1295 | if (ret <= 0) { |
1296 | QEMUIOVector local_qiov; |
1297 | |
1298 | /* Must copy-on-read; use the bounce buffer */ |
1299 | pnum = MIN(pnum, MAX_BOUNCE_BUFFER); |
1300 | if (!bounce_buffer) { |
1301 | int64_t max_we_need = MAX(pnum, cluster_bytes - pnum); |
1302 | int64_t max_allowed = MIN(max_transfer, MAX_BOUNCE_BUFFER); |
1303 | int64_t bounce_buffer_len = MIN(max_we_need, max_allowed); |
1304 | |
1305 | bounce_buffer = qemu_try_blockalign(bs, bounce_buffer_len); |
1306 | if (!bounce_buffer) { |
1307 | ret = -ENOMEM; |
1308 | goto err; |
1309 | } |
1310 | } |
1311 | qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum); |
1312 | |
1313 | ret = bdrv_driver_preadv(bs, cluster_offset, pnum, |
1314 | &local_qiov, 0, 0); |
1315 | if (ret < 0) { |
1316 | goto err; |
1317 | } |
1318 | |
1319 | bdrv_debug_event(bs, BLKDBG_COR_WRITE); |
1320 | if (drv->bdrv_co_pwrite_zeroes && |
1321 | buffer_is_zero(bounce_buffer, pnum)) { |
1322 | /* FIXME: Should we (perhaps conditionally) be setting |
1323 | * BDRV_REQ_MAY_UNMAP, if it will allow for a sparser copy |
1324 | * that still correctly reads as zero? */ |
1325 | ret = bdrv_co_do_pwrite_zeroes(bs, cluster_offset, pnum, |
1326 | BDRV_REQ_WRITE_UNCHANGED); |
1327 | } else { |
1328 | /* This does not change the data on the disk, it is not |
1329 | * necessary to flush even in cache=writethrough mode. |
1330 | */ |
1331 | ret = bdrv_driver_pwritev(bs, cluster_offset, pnum, |
1332 | &local_qiov, 0, |
1333 | BDRV_REQ_WRITE_UNCHANGED); |
1334 | } |
1335 | |
1336 | if (ret < 0) { |
1337 | /* It might be okay to ignore write errors for guest |
1338 | * requests. If this is a deliberate copy-on-read |
1339 | * then we don't want to ignore the error. Simply |
1340 | * report it in all cases. |
1341 | */ |
1342 | goto err; |
1343 | } |
1344 | |
1345 | if (!(flags & BDRV_REQ_PREFETCH)) { |
1346 | qemu_iovec_from_buf(qiov, qiov_offset + progress, |
1347 | bounce_buffer + skip_bytes, |
1348 | pnum - skip_bytes); |
1349 | } |
1350 | } else if (!(flags & BDRV_REQ_PREFETCH)) { |
1351 | /* Read directly into the destination */ |
1352 | ret = bdrv_driver_preadv(bs, offset + progress, |
1353 | MIN(pnum - skip_bytes, bytes - progress), |
1354 | qiov, qiov_offset + progress, 0); |
1355 | if (ret < 0) { |
1356 | goto err; |
1357 | } |
1358 | } |
1359 | |
1360 | cluster_offset += pnum; |
1361 | cluster_bytes -= pnum; |
1362 | progress += pnum - skip_bytes; |
1363 | skip_bytes = 0; |
1364 | } |
1365 | ret = 0; |
1366 | |
1367 | err: |
1368 | qemu_vfree(bounce_buffer); |
1369 | return ret; |
1370 | } |
1371 | |
1372 | /* |
1373 | * Forwards an already correctly aligned request to the BlockDriver. This |
1374 | * handles copy on read, zeroing after EOF, and fragmentation of large |
1375 | * reads; any other features must be implemented by the caller. |
1376 | */ |
1377 | static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child, |
1378 | BdrvTrackedRequest *req, int64_t offset, unsigned int bytes, |
1379 | int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags) |
1380 | { |
1381 | BlockDriverState *bs = child->bs; |
1382 | int64_t total_bytes, max_bytes; |
1383 | int ret = 0; |
1384 | uint64_t bytes_remaining = bytes; |
1385 | int max_transfer; |
1386 | |
1387 | assert(is_power_of_2(align)); |
1388 | assert((offset & (align - 1)) == 0); |
1389 | assert((bytes & (align - 1)) == 0); |
1390 | assert((bs->open_flags & BDRV_O_NO_IO) == 0); |
1391 | max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX), |
1392 | align); |
1393 | |
1394 | /* TODO: We would need a per-BDS .supported_read_flags and |
1395 | * potential fallback support, if we ever implement any read flags |
1396 | * to pass through to drivers. For now, there aren't any |
1397 | * passthrough flags. */ |
1398 | assert(!(flags & ~(BDRV_REQ_NO_SERIALISING | BDRV_REQ_COPY_ON_READ | |
1399 | BDRV_REQ_PREFETCH))); |
1400 | |
1401 | /* Handle Copy on Read and associated serialisation */ |
1402 | if (flags & BDRV_REQ_COPY_ON_READ) { |
1403 | /* If we touch the same cluster it counts as an overlap. This |
1404 | * guarantees that allocating writes will be serialized and not race |
1405 | * with each other for the same cluster. For example, in copy-on-read |
1406 | * it ensures that the CoR read and write operations are atomic and |
1407 | * guest writes cannot interleave between them. */ |
1408 | mark_request_serialising(req, bdrv_get_cluster_size(bs)); |
1409 | } |
1410 | |
1411 | /* BDRV_REQ_SERIALISING is only for write operation */ |
1412 | assert(!(flags & BDRV_REQ_SERIALISING)); |
1413 | |
1414 | if (!(flags & BDRV_REQ_NO_SERIALISING)) { |
1415 | wait_serialising_requests(req); |
1416 | } |
1417 | |
1418 | if (flags & BDRV_REQ_COPY_ON_READ) { |
1419 | int64_t pnum; |
1420 | |
1421 | ret = bdrv_is_allocated(bs, offset, bytes, &pnum); |
1422 | if (ret < 0) { |
1423 | goto out; |
1424 | } |
1425 | |
1426 | if (!ret || pnum != bytes) { |
1427 | ret = bdrv_co_do_copy_on_readv(child, offset, bytes, |
1428 | qiov, qiov_offset, flags); |
1429 | goto out; |
1430 | } else if (flags & BDRV_REQ_PREFETCH) { |
1431 | goto out; |
1432 | } |
1433 | } |
1434 | |
1435 | /* Forward the request to the BlockDriver, possibly fragmenting it */ |
1436 | total_bytes = bdrv_getlength(bs); |
1437 | if (total_bytes < 0) { |
1438 | ret = total_bytes; |
1439 | goto out; |
1440 | } |
1441 | |
1442 | max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align); |
1443 | if (bytes <= max_bytes && bytes <= max_transfer) { |
1444 | ret = bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, 0); |
1445 | goto out; |
1446 | } |
1447 | |
1448 | while (bytes_remaining) { |
1449 | int num; |
1450 | |
1451 | if (max_bytes) { |
1452 | num = MIN(bytes_remaining, MIN(max_bytes, max_transfer)); |
1453 | assert(num); |
1454 | |
1455 | ret = bdrv_driver_preadv(bs, offset + bytes - bytes_remaining, |
1456 | num, qiov, bytes - bytes_remaining, 0); |
1457 | max_bytes -= num; |
1458 | } else { |
1459 | num = bytes_remaining; |
1460 | ret = qemu_iovec_memset(qiov, bytes - bytes_remaining, 0, |
1461 | bytes_remaining); |
1462 | } |
1463 | if (ret < 0) { |
1464 | goto out; |
1465 | } |
1466 | bytes_remaining -= num; |
1467 | } |
1468 | |
1469 | out: |
1470 | return ret < 0 ? ret : 0; |
1471 | } |
1472 | |
1473 | /* |
1474 | * Request padding |
1475 | * |
1476 | * |<---- align ----->| |<----- align ---->| |
1477 | * |<- head ->|<------------- bytes ------------->|<-- tail -->| |
1478 | * | | | | | | |
1479 | * -*----------$-------*-------- ... --------*-----$------------*--- |
1480 | * | | | | | | |
1481 | * | offset | | end | |
1482 | * ALIGN_DOWN(offset) ALIGN_UP(offset) ALIGN_DOWN(end) ALIGN_UP(end) |
1483 | * [buf ... ) [tail_buf ) |
1484 | * |
1485 | * @buf is an aligned allocation needed to store @head and @tail paddings. @head |
1486 | * is placed at the beginning of @buf and @tail at the @end. |
1487 | * |
1488 | * @tail_buf is a pointer to sub-buffer, corresponding to align-sized chunk |
1489 | * around tail, if tail exists. |
1490 | * |
1491 | * @merge_reads is true for small requests, |
1492 | * if @buf_len == @head + bytes + @tail. In this case it is possible that both |
1493 | * head and tail exist but @buf_len == align and @tail_buf == @buf. |
1494 | */ |
1495 | typedef struct BdrvRequestPadding { |
1496 | uint8_t *buf; |
1497 | size_t buf_len; |
1498 | uint8_t *tail_buf; |
1499 | size_t head; |
1500 | size_t tail; |
1501 | bool merge_reads; |
1502 | QEMUIOVector local_qiov; |
1503 | } BdrvRequestPadding; |
1504 | |
1505 | static bool bdrv_init_padding(BlockDriverState *bs, |
1506 | int64_t offset, int64_t bytes, |
1507 | BdrvRequestPadding *pad) |
1508 | { |
1509 | uint64_t align = bs->bl.request_alignment; |
1510 | size_t sum; |
1511 | |
1512 | memset(pad, 0, sizeof(*pad)); |
1513 | |
1514 | pad->head = offset & (align - 1); |
1515 | pad->tail = ((offset + bytes) & (align - 1)); |
1516 | if (pad->tail) { |
1517 | pad->tail = align - pad->tail; |
1518 | } |
1519 | |
1520 | if ((!pad->head && !pad->tail) || !bytes) { |
1521 | return false; |
1522 | } |
1523 | |
1524 | sum = pad->head + bytes + pad->tail; |
1525 | pad->buf_len = (sum > align && pad->head && pad->tail) ? 2 * align : align; |
1526 | pad->buf = qemu_blockalign(bs, pad->buf_len); |
1527 | pad->merge_reads = sum == pad->buf_len; |
1528 | if (pad->tail) { |
1529 | pad->tail_buf = pad->buf + pad->buf_len - align; |
1530 | } |
1531 | |
1532 | return true; |
1533 | } |
1534 | |
1535 | static int bdrv_padding_rmw_read(BdrvChild *child, |
1536 | BdrvTrackedRequest *req, |
1537 | BdrvRequestPadding *pad, |
1538 | bool zero_middle) |
1539 | { |
1540 | QEMUIOVector local_qiov; |
1541 | BlockDriverState *bs = child->bs; |
1542 | uint64_t align = bs->bl.request_alignment; |
1543 | int ret; |
1544 | |
1545 | assert(req->serialising && pad->buf); |
1546 | |
1547 | if (pad->head || pad->merge_reads) { |
1548 | uint64_t bytes = pad->merge_reads ? pad->buf_len : align; |
1549 | |
1550 | qemu_iovec_init_buf(&local_qiov, pad->buf, bytes); |
1551 | |
1552 | if (pad->head) { |
1553 | bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD); |
1554 | } |
1555 | if (pad->merge_reads && pad->tail) { |
1556 | bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL); |
1557 | } |
1558 | ret = bdrv_aligned_preadv(child, req, req->overlap_offset, bytes, |
1559 | align, &local_qiov, 0, 0); |
1560 | if (ret < 0) { |
1561 | return ret; |
1562 | } |
1563 | if (pad->head) { |
1564 | bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD); |
1565 | } |
1566 | if (pad->merge_reads && pad->tail) { |
1567 | bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL); |
1568 | } |
1569 | |
1570 | if (pad->merge_reads) { |
1571 | goto zero_mem; |
1572 | } |
1573 | } |
1574 | |
1575 | if (pad->tail) { |
1576 | qemu_iovec_init_buf(&local_qiov, pad->tail_buf, align); |
1577 | |
1578 | bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL); |
1579 | ret = bdrv_aligned_preadv( |
1580 | child, req, |
1581 | req->overlap_offset + req->overlap_bytes - align, |
1582 | align, align, &local_qiov, 0, 0); |
1583 | if (ret < 0) { |
1584 | return ret; |
1585 | } |
1586 | bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL); |
1587 | } |
1588 | |
1589 | zero_mem: |
1590 | if (zero_middle) { |
1591 | memset(pad->buf + pad->head, 0, pad->buf_len - pad->head - pad->tail); |
1592 | } |
1593 | |
1594 | return 0; |
1595 | } |
1596 | |
1597 | static void bdrv_padding_destroy(BdrvRequestPadding *pad) |
1598 | { |
1599 | if (pad->buf) { |
1600 | qemu_vfree(pad->buf); |
1601 | qemu_iovec_destroy(&pad->local_qiov); |
1602 | } |
1603 | } |
1604 | |
1605 | /* |
1606 | * bdrv_pad_request |
1607 | * |
1608 | * Exchange request parameters with padded request if needed. Don't include RMW |
1609 | * read of padding, bdrv_padding_rmw_read() should be called separately if |
1610 | * needed. |
1611 | * |
1612 | * All parameters except @bs are in-out: they represent original request at |
1613 | * function call and padded (if padding needed) at function finish. |
1614 | * |
1615 | * Function always succeeds. |
1616 | */ |
1617 | static bool bdrv_pad_request(BlockDriverState *bs, |
1618 | QEMUIOVector **qiov, size_t *qiov_offset, |
1619 | int64_t *offset, unsigned int *bytes, |
1620 | BdrvRequestPadding *pad) |
1621 | { |
1622 | if (!bdrv_init_padding(bs, *offset, *bytes, pad)) { |
1623 | return false; |
1624 | } |
1625 | |
1626 | qemu_iovec_init_extended(&pad->local_qiov, pad->buf, pad->head, |
1627 | *qiov, *qiov_offset, *bytes, |
1628 | pad->buf + pad->buf_len - pad->tail, pad->tail); |
1629 | *bytes += pad->head + pad->tail; |
1630 | *offset -= pad->head; |
1631 | *qiov = &pad->local_qiov; |
1632 | *qiov_offset = 0; |
1633 | |
1634 | return true; |
1635 | } |
1636 | |
1637 | int coroutine_fn bdrv_co_preadv(BdrvChild *child, |
1638 | int64_t offset, unsigned int bytes, QEMUIOVector *qiov, |
1639 | BdrvRequestFlags flags) |
1640 | { |
1641 | return bdrv_co_preadv_part(child, offset, bytes, qiov, 0, flags); |
1642 | } |
1643 | |
1644 | int coroutine_fn bdrv_co_preadv_part(BdrvChild *child, |
1645 | int64_t offset, unsigned int bytes, |
1646 | QEMUIOVector *qiov, size_t qiov_offset, |
1647 | BdrvRequestFlags flags) |
1648 | { |
1649 | BlockDriverState *bs = child->bs; |
1650 | BdrvTrackedRequest req; |
1651 | BdrvRequestPadding pad; |
1652 | int ret; |
1653 | |
1654 | trace_bdrv_co_preadv(bs, offset, bytes, flags); |
1655 | |
1656 | ret = bdrv_check_byte_request(bs, offset, bytes); |
1657 | if (ret < 0) { |
1658 | return ret; |
1659 | } |
1660 | |
1661 | bdrv_inc_in_flight(bs); |
1662 | |
1663 | /* Don't do copy-on-read if we read data before write operation */ |
1664 | if (atomic_read(&bs->copy_on_read) && !(flags & BDRV_REQ_NO_SERIALISING)) { |
1665 | flags |= BDRV_REQ_COPY_ON_READ; |
1666 | } |
1667 | |
1668 | bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, &pad); |
1669 | |
1670 | tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_READ); |
1671 | ret = bdrv_aligned_preadv(child, &req, offset, bytes, |
1672 | bs->bl.request_alignment, |
1673 | qiov, qiov_offset, flags); |
1674 | tracked_request_end(&req); |
1675 | bdrv_dec_in_flight(bs); |
1676 | |
1677 | bdrv_padding_destroy(&pad); |
1678 | |
1679 | return ret; |
1680 | } |
1681 | |
1682 | static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, |
1683 | int64_t offset, int bytes, BdrvRequestFlags flags) |
1684 | { |
1685 | BlockDriver *drv = bs->drv; |
1686 | QEMUIOVector qiov; |
1687 | void *buf = NULL; |
1688 | int ret = 0; |
1689 | bool need_flush = false; |
1690 | int head = 0; |
1691 | int tail = 0; |
1692 | |
1693 | int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_pwrite_zeroes, INT_MAX); |
1694 | int alignment = MAX(bs->bl.pwrite_zeroes_alignment, |
1695 | bs->bl.request_alignment); |
1696 | int max_transfer = MIN_NON_ZERO(bs->bl.max_transfer, MAX_BOUNCE_BUFFER); |
1697 | |
1698 | if (!drv) { |
1699 | return -ENOMEDIUM; |
1700 | } |
1701 | |
1702 | if ((flags & ~bs->supported_zero_flags) & BDRV_REQ_NO_FALLBACK) { |
1703 | return -ENOTSUP; |
1704 | } |
1705 | |
1706 | assert(alignment % bs->bl.request_alignment == 0); |
1707 | head = offset % alignment; |
1708 | tail = (offset + bytes) % alignment; |
1709 | max_write_zeroes = QEMU_ALIGN_DOWN(max_write_zeroes, alignment); |
1710 | assert(max_write_zeroes >= bs->bl.request_alignment); |
1711 | |
1712 | while (bytes > 0 && !ret) { |
1713 | int num = bytes; |
1714 | |
1715 | /* Align request. Block drivers can expect the "bulk" of the request |
1716 | * to be aligned, and that unaligned requests do not cross cluster |
1717 | * boundaries. |
1718 | */ |
1719 | if (head) { |
1720 | /* Make a small request up to the first aligned sector. For |
1721 | * convenience, limit this request to max_transfer even if |
1722 | * we don't need to fall back to writes. */ |
1723 | num = MIN(MIN(bytes, max_transfer), alignment - head); |
1724 | head = (head + num) % alignment; |
1725 | assert(num < max_write_zeroes); |
1726 | } else if (tail && num > alignment) { |
1727 | /* Shorten the request to the last aligned sector. */ |
1728 | num -= tail; |
1729 | } |
1730 | |
1731 | /* limit request size */ |
1732 | if (num > max_write_zeroes) { |
1733 | num = max_write_zeroes; |
1734 | } |
1735 | |
1736 | ret = -ENOTSUP; |
1737 | /* First try the efficient write zeroes operation */ |
1738 | if (drv->bdrv_co_pwrite_zeroes) { |
1739 | ret = drv->bdrv_co_pwrite_zeroes(bs, offset, num, |
1740 | flags & bs->supported_zero_flags); |
1741 | if (ret != -ENOTSUP && (flags & BDRV_REQ_FUA) && |
1742 | !(bs->supported_zero_flags & BDRV_REQ_FUA)) { |
1743 | need_flush = true; |
1744 | } |
1745 | } else { |
1746 | assert(!bs->supported_zero_flags); |
1747 | } |
1748 | |
1749 | if (ret < 0 && !(flags & BDRV_REQ_NO_FALLBACK)) { |
1750 | /* Fall back to bounce buffer if write zeroes is unsupported */ |
1751 | BdrvRequestFlags write_flags = flags & ~BDRV_REQ_ZERO_WRITE; |
1752 | |
1753 | if ((flags & BDRV_REQ_FUA) && |
1754 | !(bs->supported_write_flags & BDRV_REQ_FUA)) { |
1755 | /* No need for bdrv_driver_pwrite() to do a fallback |
1756 | * flush on each chunk; use just one at the end */ |
1757 | write_flags &= ~BDRV_REQ_FUA; |
1758 | need_flush = true; |
1759 | } |
1760 | num = MIN(num, max_transfer); |
1761 | if (buf == NULL) { |
1762 | buf = qemu_try_blockalign0(bs, num); |
1763 | if (buf == NULL) { |
1764 | ret = -ENOMEM; |
1765 | goto fail; |
1766 | } |
1767 | } |
1768 | qemu_iovec_init_buf(&qiov, buf, num); |
1769 | |
1770 | ret = bdrv_driver_pwritev(bs, offset, num, &qiov, 0, write_flags); |
1771 | |
1772 | /* Keep bounce buffer around if it is big enough for all |
1773 | * all future requests. |
1774 | */ |
1775 | if (num < max_transfer) { |
1776 | qemu_vfree(buf); |
1777 | buf = NULL; |
1778 | } |
1779 | } |
1780 | |
1781 | offset += num; |
1782 | bytes -= num; |
1783 | } |
1784 | |
1785 | fail: |
1786 | if (ret == 0 && need_flush) { |
1787 | ret = bdrv_co_flush(bs); |
1788 | } |
1789 | qemu_vfree(buf); |
1790 | return ret; |
1791 | } |
1792 | |
1793 | static inline int coroutine_fn |
1794 | bdrv_co_write_req_prepare(BdrvChild *child, int64_t offset, uint64_t bytes, |
1795 | BdrvTrackedRequest *req, int flags) |
1796 | { |
1797 | BlockDriverState *bs = child->bs; |
1798 | bool waited; |
1799 | int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE); |
1800 | |
1801 | if (bs->read_only) { |
1802 | return -EPERM; |
1803 | } |
1804 | |
1805 | /* BDRV_REQ_NO_SERIALISING is only for read operation */ |
1806 | assert(!(flags & BDRV_REQ_NO_SERIALISING)); |
1807 | assert(!(bs->open_flags & BDRV_O_INACTIVE)); |
1808 | assert((bs->open_flags & BDRV_O_NO_IO) == 0); |
1809 | assert(!(flags & ~BDRV_REQ_MASK)); |
1810 | |
1811 | if (flags & BDRV_REQ_SERIALISING) { |
1812 | mark_request_serialising(req, bdrv_get_cluster_size(bs)); |
1813 | } |
1814 | |
1815 | waited = wait_serialising_requests(req); |
1816 | |
1817 | assert(!waited || !req->serialising || |
1818 | is_request_serialising_and_aligned(req)); |
1819 | assert(req->overlap_offset <= offset); |
1820 | assert(offset + bytes <= req->overlap_offset + req->overlap_bytes); |
1821 | assert(end_sector <= bs->total_sectors || child->perm & BLK_PERM_RESIZE); |
1822 | |
1823 | switch (req->type) { |
1824 | case BDRV_TRACKED_WRITE: |
1825 | case BDRV_TRACKED_DISCARD: |
1826 | if (flags & BDRV_REQ_WRITE_UNCHANGED) { |
1827 | assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE)); |
1828 | } else { |
1829 | assert(child->perm & BLK_PERM_WRITE); |
1830 | } |
1831 | return notifier_with_return_list_notify(&bs->before_write_notifiers, |
1832 | req); |
1833 | case BDRV_TRACKED_TRUNCATE: |
1834 | assert(child->perm & BLK_PERM_RESIZE); |
1835 | return 0; |
1836 | default: |
1837 | abort(); |
1838 | } |
1839 | } |
1840 | |
1841 | static inline void coroutine_fn |
1842 | bdrv_co_write_req_finish(BdrvChild *child, int64_t offset, uint64_t bytes, |
1843 | BdrvTrackedRequest *req, int ret) |
1844 | { |
1845 | int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE); |
1846 | BlockDriverState *bs = child->bs; |
1847 | |
1848 | atomic_inc(&bs->write_gen); |
1849 | |
1850 | /* |
1851 | * Discard cannot extend the image, but in error handling cases, such as |
1852 | * when reverting a qcow2 cluster allocation, the discarded range can pass |
1853 | * the end of image file, so we cannot assert about BDRV_TRACKED_DISCARD |
1854 | * here. Instead, just skip it, since semantically a discard request |
1855 | * beyond EOF cannot expand the image anyway. |
1856 | */ |
1857 | if (ret == 0 && |
1858 | (req->type == BDRV_TRACKED_TRUNCATE || |
1859 | end_sector > bs->total_sectors) && |
1860 | req->type != BDRV_TRACKED_DISCARD) { |
1861 | bs->total_sectors = end_sector; |
1862 | bdrv_parent_cb_resize(bs); |
1863 | bdrv_dirty_bitmap_truncate(bs, end_sector << BDRV_SECTOR_BITS); |
1864 | } |
1865 | if (req->bytes) { |
1866 | switch (req->type) { |
1867 | case BDRV_TRACKED_WRITE: |
1868 | stat64_max(&bs->wr_highest_offset, offset + bytes); |
1869 | /* fall through, to set dirty bits */ |
1870 | case BDRV_TRACKED_DISCARD: |
1871 | bdrv_set_dirty(bs, offset, bytes); |
1872 | break; |
1873 | default: |
1874 | break; |
1875 | } |
1876 | } |
1877 | } |
1878 | |
1879 | /* |
1880 | * Forwards an already correctly aligned write request to the BlockDriver, |
1881 | * after possibly fragmenting it. |
1882 | */ |
1883 | static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child, |
1884 | BdrvTrackedRequest *req, int64_t offset, unsigned int bytes, |
1885 | int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags) |
1886 | { |
1887 | BlockDriverState *bs = child->bs; |
1888 | BlockDriver *drv = bs->drv; |
1889 | int ret; |
1890 | |
1891 | uint64_t bytes_remaining = bytes; |
1892 | int max_transfer; |
1893 | |
1894 | if (!drv) { |
1895 | return -ENOMEDIUM; |
1896 | } |
1897 | |
1898 | if (bdrv_has_readonly_bitmaps(bs)) { |
1899 | return -EPERM; |
1900 | } |
1901 | |
1902 | assert(is_power_of_2(align)); |
1903 | assert((offset & (align - 1)) == 0); |
1904 | assert((bytes & (align - 1)) == 0); |
1905 | assert(!qiov || qiov_offset + bytes <= qiov->size); |
1906 | max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX), |
1907 | align); |
1908 | |
1909 | ret = bdrv_co_write_req_prepare(child, offset, bytes, req, flags); |
1910 | |
1911 | if (!ret && bs->detect_zeroes != BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF && |
1912 | !(flags & BDRV_REQ_ZERO_WRITE) && drv->bdrv_co_pwrite_zeroes && |
1913 | qemu_iovec_is_zero(qiov, qiov_offset, bytes)) { |
1914 | flags |= BDRV_REQ_ZERO_WRITE; |
1915 | if (bs->detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP) { |
1916 | flags |= BDRV_REQ_MAY_UNMAP; |
1917 | } |
1918 | } |
1919 | |
1920 | if (ret < 0) { |
1921 | /* Do nothing, write notifier decided to fail this request */ |
1922 | } else if (flags & BDRV_REQ_ZERO_WRITE) { |
1923 | bdrv_debug_event(bs, BLKDBG_PWRITEV_ZERO); |
1924 | ret = bdrv_co_do_pwrite_zeroes(bs, offset, bytes, flags); |
1925 | } else if (flags & BDRV_REQ_WRITE_COMPRESSED) { |
1926 | ret = bdrv_driver_pwritev_compressed(bs, offset, bytes, |
1927 | qiov, qiov_offset); |
1928 | } else if (bytes <= max_transfer) { |
1929 | bdrv_debug_event(bs, BLKDBG_PWRITEV); |
1930 | ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, qiov_offset, flags); |
1931 | } else { |
1932 | bdrv_debug_event(bs, BLKDBG_PWRITEV); |
1933 | while (bytes_remaining) { |
1934 | int num = MIN(bytes_remaining, max_transfer); |
1935 | int local_flags = flags; |
1936 | |
1937 | assert(num); |
1938 | if (num < bytes_remaining && (flags & BDRV_REQ_FUA) && |
1939 | !(bs->supported_write_flags & BDRV_REQ_FUA)) { |
1940 | /* If FUA is going to be emulated by flush, we only |
1941 | * need to flush on the last iteration */ |
1942 | local_flags &= ~BDRV_REQ_FUA; |
1943 | } |
1944 | |
1945 | ret = bdrv_driver_pwritev(bs, offset + bytes - bytes_remaining, |
1946 | num, qiov, bytes - bytes_remaining, |
1947 | local_flags); |
1948 | if (ret < 0) { |
1949 | break; |
1950 | } |
1951 | bytes_remaining -= num; |
1952 | } |
1953 | } |
1954 | bdrv_debug_event(bs, BLKDBG_PWRITEV_DONE); |
1955 | |
1956 | if (ret >= 0) { |
1957 | ret = 0; |
1958 | } |
1959 | bdrv_co_write_req_finish(child, offset, bytes, req, ret); |
1960 | |
1961 | return ret; |
1962 | } |
1963 | |
1964 | static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child, |
1965 | int64_t offset, |
1966 | unsigned int bytes, |
1967 | BdrvRequestFlags flags, |
1968 | BdrvTrackedRequest *req) |
1969 | { |
1970 | BlockDriverState *bs = child->bs; |
1971 | QEMUIOVector local_qiov; |
1972 | uint64_t align = bs->bl.request_alignment; |
1973 | int ret = 0; |
1974 | bool padding; |
1975 | BdrvRequestPadding pad; |
1976 | |
1977 | padding = bdrv_init_padding(bs, offset, bytes, &pad); |
1978 | if (padding) { |
1979 | mark_request_serialising(req, align); |
1980 | wait_serialising_requests(req); |
1981 | |
1982 | bdrv_padding_rmw_read(child, req, &pad, true); |
1983 | |
1984 | if (pad.head || pad.merge_reads) { |
1985 | int64_t aligned_offset = offset & ~(align - 1); |
1986 | int64_t write_bytes = pad.merge_reads ? pad.buf_len : align; |
1987 | |
1988 | qemu_iovec_init_buf(&local_qiov, pad.buf, write_bytes); |
1989 | ret = bdrv_aligned_pwritev(child, req, aligned_offset, write_bytes, |
1990 | align, &local_qiov, 0, |
1991 | flags & ~BDRV_REQ_ZERO_WRITE); |
1992 | if (ret < 0 || pad.merge_reads) { |
1993 | /* Error or all work is done */ |
1994 | goto out; |
1995 | } |
1996 | offset += write_bytes - pad.head; |
1997 | bytes -= write_bytes - pad.head; |
1998 | } |
1999 | } |
2000 | |
2001 | assert(!bytes || (offset & (align - 1)) == 0); |
2002 | if (bytes >= align) { |
2003 | /* Write the aligned part in the middle. */ |
2004 | uint64_t aligned_bytes = bytes & ~(align - 1); |
2005 | ret = bdrv_aligned_pwritev(child, req, offset, aligned_bytes, align, |
2006 | NULL, 0, flags); |
2007 | if (ret < 0) { |
2008 | goto out; |
2009 | } |
2010 | bytes -= aligned_bytes; |
2011 | offset += aligned_bytes; |
2012 | } |
2013 | |
2014 | assert(!bytes || (offset & (align - 1)) == 0); |
2015 | if (bytes) { |
2016 | assert(align == pad.tail + bytes); |
2017 | |
2018 | qemu_iovec_init_buf(&local_qiov, pad.tail_buf, align); |
2019 | ret = bdrv_aligned_pwritev(child, req, offset, align, align, |
2020 | &local_qiov, 0, |
2021 | flags & ~BDRV_REQ_ZERO_WRITE); |
2022 | } |
2023 | |
2024 | out: |
2025 | bdrv_padding_destroy(&pad); |
2026 | |
2027 | return ret; |
2028 | } |
2029 | |
2030 | /* |
2031 | * Handle a write request in coroutine context |
2032 | */ |
2033 | int coroutine_fn bdrv_co_pwritev(BdrvChild *child, |
2034 | int64_t offset, unsigned int bytes, QEMUIOVector *qiov, |
2035 | BdrvRequestFlags flags) |
2036 | { |
2037 | return bdrv_co_pwritev_part(child, offset, bytes, qiov, 0, flags); |
2038 | } |
2039 | |
2040 | int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child, |
2041 | int64_t offset, unsigned int bytes, QEMUIOVector *qiov, size_t qiov_offset, |
2042 | BdrvRequestFlags flags) |
2043 | { |
2044 | BlockDriverState *bs = child->bs; |
2045 | BdrvTrackedRequest req; |
2046 | uint64_t align = bs->bl.request_alignment; |
2047 | BdrvRequestPadding pad; |
2048 | int ret; |
2049 | |
2050 | trace_bdrv_co_pwritev(child->bs, offset, bytes, flags); |
2051 | |
2052 | if (!bs->drv) { |
2053 | return -ENOMEDIUM; |
2054 | } |
2055 | |
2056 | ret = bdrv_check_byte_request(bs, offset, bytes); |
2057 | if (ret < 0) { |
2058 | return ret; |
2059 | } |
2060 | |
2061 | bdrv_inc_in_flight(bs); |
2062 | /* |
2063 | * Align write if necessary by performing a read-modify-write cycle. |
2064 | * Pad qiov with the read parts and be sure to have a tracked request not |
2065 | * only for bdrv_aligned_pwritev, but also for the reads of the RMW cycle. |
2066 | */ |
2067 | tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_WRITE); |
2068 | |
2069 | if (flags & BDRV_REQ_ZERO_WRITE) { |
2070 | ret = bdrv_co_do_zero_pwritev(child, offset, bytes, flags, &req); |
2071 | goto out; |
2072 | } |
2073 | |
2074 | if (bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, &pad)) { |
2075 | mark_request_serialising(&req, align); |
2076 | wait_serialising_requests(&req); |
2077 | bdrv_padding_rmw_read(child, &req, &pad, false); |
2078 | } |
2079 | |
2080 | ret = bdrv_aligned_pwritev(child, &req, offset, bytes, align, |
2081 | qiov, qiov_offset, flags); |
2082 | |
2083 | bdrv_padding_destroy(&pad); |
2084 | |
2085 | out: |
2086 | tracked_request_end(&req); |
2087 | bdrv_dec_in_flight(bs); |
2088 | |
2089 | return ret; |
2090 | } |
2091 | |
2092 | int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset, |
2093 | int bytes, BdrvRequestFlags flags) |
2094 | { |
2095 | trace_bdrv_co_pwrite_zeroes(child->bs, offset, bytes, flags); |
2096 | |
2097 | if (!(child->bs->open_flags & BDRV_O_UNMAP)) { |
2098 | flags &= ~BDRV_REQ_MAY_UNMAP; |
2099 | } |
2100 | |
2101 | return bdrv_co_pwritev(child, offset, bytes, NULL, |
2102 | BDRV_REQ_ZERO_WRITE | flags); |
2103 | } |
2104 | |
2105 | /* |
2106 | * Flush ALL BDSes regardless of if they are reachable via a BlkBackend or not. |
2107 | */ |
2108 | int bdrv_flush_all(void) |
2109 | { |
2110 | BdrvNextIterator it; |
2111 | BlockDriverState *bs = NULL; |
2112 | int result = 0; |
2113 | |
2114 | for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
2115 | AioContext *aio_context = bdrv_get_aio_context(bs); |
2116 | int ret; |
2117 | |
2118 | aio_context_acquire(aio_context); |
2119 | ret = bdrv_flush(bs); |
2120 | if (ret < 0 && !result) { |
2121 | result = ret; |
2122 | } |
2123 | aio_context_release(aio_context); |
2124 | } |
2125 | |
2126 | return result; |
2127 | } |
2128 | |
2129 | |
2130 | typedef struct BdrvCoBlockStatusData { |
2131 | BlockDriverState *bs; |
2132 | BlockDriverState *base; |
2133 | bool want_zero; |
2134 | int64_t offset; |
2135 | int64_t bytes; |
2136 | int64_t *pnum; |
2137 | int64_t *map; |
2138 | BlockDriverState **file; |
2139 | int ret; |
2140 | bool done; |
2141 | } BdrvCoBlockStatusData; |
2142 | |
2143 | int coroutine_fn bdrv_co_block_status_from_file(BlockDriverState *bs, |
2144 | bool want_zero, |
2145 | int64_t offset, |
2146 | int64_t bytes, |
2147 | int64_t *pnum, |
2148 | int64_t *map, |
2149 | BlockDriverState **file) |
2150 | { |
2151 | assert(bs->file && bs->file->bs); |
2152 | *pnum = bytes; |
2153 | *map = offset; |
2154 | *file = bs->file->bs; |
2155 | return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID; |
2156 | } |
2157 | |
2158 | int coroutine_fn bdrv_co_block_status_from_backing(BlockDriverState *bs, |
2159 | bool want_zero, |
2160 | int64_t offset, |
2161 | int64_t bytes, |
2162 | int64_t *pnum, |
2163 | int64_t *map, |
2164 | BlockDriverState **file) |
2165 | { |
2166 | assert(bs->backing && bs->backing->bs); |
2167 | *pnum = bytes; |
2168 | *map = offset; |
2169 | *file = bs->backing->bs; |
2170 | return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID; |
2171 | } |
2172 | |
2173 | /* |
2174 | * Returns the allocation status of the specified sectors. |
2175 | * Drivers not implementing the functionality are assumed to not support |
2176 | * backing files, hence all their sectors are reported as allocated. |
2177 | * |
2178 | * If 'want_zero' is true, the caller is querying for mapping |
2179 | * purposes, with a focus on valid BDRV_BLOCK_OFFSET_VALID, _DATA, and |
2180 | * _ZERO where possible; otherwise, the result favors larger 'pnum', |
2181 | * with a focus on accurate BDRV_BLOCK_ALLOCATED. |
2182 | * |
2183 | * If 'offset' is beyond the end of the disk image the return value is |
2184 | * BDRV_BLOCK_EOF and 'pnum' is set to 0. |
2185 | * |
2186 | * 'bytes' is the max value 'pnum' should be set to. If bytes goes |
2187 | * beyond the end of the disk image it will be clamped; if 'pnum' is set to |
2188 | * the end of the image, then the returned value will include BDRV_BLOCK_EOF. |
2189 | * |
2190 | * 'pnum' is set to the number of bytes (including and immediately |
2191 | * following the specified offset) that are easily known to be in the |
2192 | * same allocated/unallocated state. Note that a second call starting |
2193 | * at the original offset plus returned pnum may have the same status. |
2194 | * The returned value is non-zero on success except at end-of-file. |
2195 | * |
2196 | * Returns negative errno on failure. Otherwise, if the |
2197 | * BDRV_BLOCK_OFFSET_VALID bit is set, 'map' and 'file' (if non-NULL) are |
2198 | * set to the host mapping and BDS corresponding to the guest offset. |
2199 | */ |
2200 | static int coroutine_fn bdrv_co_block_status(BlockDriverState *bs, |
2201 | bool want_zero, |
2202 | int64_t offset, int64_t bytes, |
2203 | int64_t *pnum, int64_t *map, |
2204 | BlockDriverState **file) |
2205 | { |
2206 | int64_t total_size; |
2207 | int64_t n; /* bytes */ |
2208 | int ret; |
2209 | int64_t local_map = 0; |
2210 | BlockDriverState *local_file = NULL; |
2211 | int64_t aligned_offset, aligned_bytes; |
2212 | uint32_t align; |
2213 | |
2214 | assert(pnum); |
2215 | *pnum = 0; |
2216 | total_size = bdrv_getlength(bs); |
2217 | if (total_size < 0) { |
2218 | ret = total_size; |
2219 | goto early_out; |
2220 | } |
2221 | |
2222 | if (offset >= total_size) { |
2223 | ret = BDRV_BLOCK_EOF; |
2224 | goto early_out; |
2225 | } |
2226 | if (!bytes) { |
2227 | ret = 0; |
2228 | goto early_out; |
2229 | } |
2230 | |
2231 | n = total_size - offset; |
2232 | if (n < bytes) { |
2233 | bytes = n; |
2234 | } |
2235 | |
2236 | /* Must be non-NULL or bdrv_getlength() would have failed */ |
2237 | assert(bs->drv); |
2238 | if (!bs->drv->bdrv_co_block_status) { |
2239 | *pnum = bytes; |
2240 | ret = BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED; |
2241 | if (offset + bytes == total_size) { |
2242 | ret |= BDRV_BLOCK_EOF; |
2243 | } |
2244 | if (bs->drv->protocol_name) { |
2245 | ret |= BDRV_BLOCK_OFFSET_VALID; |
2246 | local_map = offset; |
2247 | local_file = bs; |
2248 | } |
2249 | goto early_out; |
2250 | } |
2251 | |
2252 | bdrv_inc_in_flight(bs); |
2253 | |
2254 | /* Round out to request_alignment boundaries */ |
2255 | align = bs->bl.request_alignment; |
2256 | aligned_offset = QEMU_ALIGN_DOWN(offset, align); |
2257 | aligned_bytes = ROUND_UP(offset + bytes, align) - aligned_offset; |
2258 | |
2259 | ret = bs->drv->bdrv_co_block_status(bs, want_zero, aligned_offset, |
2260 | aligned_bytes, pnum, &local_map, |
2261 | &local_file); |
2262 | if (ret < 0) { |
2263 | *pnum = 0; |
2264 | goto out; |
2265 | } |
2266 | |
2267 | /* |
2268 | * The driver's result must be a non-zero multiple of request_alignment. |
2269 | * Clamp pnum and adjust map to original request. |
2270 | */ |
2271 | assert(*pnum && QEMU_IS_ALIGNED(*pnum, align) && |
2272 | align > offset - aligned_offset); |
2273 | if (ret & BDRV_BLOCK_RECURSE) { |
2274 | assert(ret & BDRV_BLOCK_DATA); |
2275 | assert(ret & BDRV_BLOCK_OFFSET_VALID); |
2276 | assert(!(ret & BDRV_BLOCK_ZERO)); |
2277 | } |
2278 | |
2279 | *pnum -= offset - aligned_offset; |
2280 | if (*pnum > bytes) { |
2281 | *pnum = bytes; |
2282 | } |
2283 | if (ret & BDRV_BLOCK_OFFSET_VALID) { |
2284 | local_map += offset - aligned_offset; |
2285 | } |
2286 | |
2287 | if (ret & BDRV_BLOCK_RAW) { |
2288 | assert(ret & BDRV_BLOCK_OFFSET_VALID && local_file); |
2289 | ret = bdrv_co_block_status(local_file, want_zero, local_map, |
2290 | *pnum, pnum, &local_map, &local_file); |
2291 | goto out; |
2292 | } |
2293 | |
2294 | if (ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ZERO)) { |
2295 | ret |= BDRV_BLOCK_ALLOCATED; |
2296 | } else if (want_zero) { |
2297 | if (bdrv_unallocated_blocks_are_zero(bs)) { |
2298 | ret |= BDRV_BLOCK_ZERO; |
2299 | } else if (bs->backing) { |
2300 | BlockDriverState *bs2 = bs->backing->bs; |
2301 | int64_t size2 = bdrv_getlength(bs2); |
2302 | |
2303 | if (size2 >= 0 && offset >= size2) { |
2304 | ret |= BDRV_BLOCK_ZERO; |
2305 | } |
2306 | } |
2307 | } |
2308 | |
2309 | if (want_zero && ret & BDRV_BLOCK_RECURSE && |
2310 | local_file && local_file != bs && |
2311 | (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) && |
2312 | (ret & BDRV_BLOCK_OFFSET_VALID)) { |
2313 | int64_t file_pnum; |
2314 | int ret2; |
2315 | |
2316 | ret2 = bdrv_co_block_status(local_file, want_zero, local_map, |
2317 | *pnum, &file_pnum, NULL, NULL); |
2318 | if (ret2 >= 0) { |
2319 | /* Ignore errors. This is just providing extra information, it |
2320 | * is useful but not necessary. |
2321 | */ |
2322 | if (ret2 & BDRV_BLOCK_EOF && |
2323 | (!file_pnum || ret2 & BDRV_BLOCK_ZERO)) { |
2324 | /* |
2325 | * It is valid for the format block driver to read |
2326 | * beyond the end of the underlying file's current |
2327 | * size; such areas read as zero. |
2328 | */ |
2329 | ret |= BDRV_BLOCK_ZERO; |
2330 | } else { |
2331 | /* Limit request to the range reported by the protocol driver */ |
2332 | *pnum = file_pnum; |
2333 | ret |= (ret2 & BDRV_BLOCK_ZERO); |
2334 | } |
2335 | } |
2336 | } |
2337 | |
2338 | out: |
2339 | bdrv_dec_in_flight(bs); |
2340 | if (ret >= 0 && offset + *pnum == total_size) { |
2341 | ret |= BDRV_BLOCK_EOF; |
2342 | } |
2343 | early_out: |
2344 | if (file) { |
2345 | *file = local_file; |
2346 | } |
2347 | if (map) { |
2348 | *map = local_map; |
2349 | } |
2350 | return ret; |
2351 | } |
2352 | |
2353 | static int coroutine_fn bdrv_co_block_status_above(BlockDriverState *bs, |
2354 | BlockDriverState *base, |
2355 | bool want_zero, |
2356 | int64_t offset, |
2357 | int64_t bytes, |
2358 | int64_t *pnum, |
2359 | int64_t *map, |
2360 | BlockDriverState **file) |
2361 | { |
2362 | BlockDriverState *p; |
2363 | int ret = 0; |
2364 | bool first = true; |
2365 | |
2366 | assert(bs != base); |
2367 | for (p = bs; p != base; p = backing_bs(p)) { |
2368 | ret = bdrv_co_block_status(p, want_zero, offset, bytes, pnum, map, |
2369 | file); |
2370 | if (ret < 0) { |
2371 | break; |
2372 | } |
2373 | if (ret & BDRV_BLOCK_ZERO && ret & BDRV_BLOCK_EOF && !first) { |
2374 | /* |
2375 | * Reading beyond the end of the file continues to read |
2376 | * zeroes, but we can only widen the result to the |
2377 | * unallocated length we learned from an earlier |
2378 | * iteration. |
2379 | */ |
2380 | *pnum = bytes; |
2381 | } |
2382 | if (ret & (BDRV_BLOCK_ZERO | BDRV_BLOCK_DATA)) { |
2383 | break; |
2384 | } |
2385 | /* [offset, pnum] unallocated on this layer, which could be only |
2386 | * the first part of [offset, bytes]. */ |
2387 | bytes = MIN(bytes, *pnum); |
2388 | first = false; |
2389 | } |
2390 | return ret; |
2391 | } |
2392 | |
2393 | /* Coroutine wrapper for bdrv_block_status_above() */ |
2394 | static void coroutine_fn bdrv_block_status_above_co_entry(void *opaque) |
2395 | { |
2396 | BdrvCoBlockStatusData *data = opaque; |
2397 | |
2398 | data->ret = bdrv_co_block_status_above(data->bs, data->base, |
2399 | data->want_zero, |
2400 | data->offset, data->bytes, |
2401 | data->pnum, data->map, data->file); |
2402 | data->done = true; |
2403 | aio_wait_kick(); |
2404 | } |
2405 | |
2406 | /* |
2407 | * Synchronous wrapper around bdrv_co_block_status_above(). |
2408 | * |
2409 | * See bdrv_co_block_status_above() for details. |
2410 | */ |
2411 | static int bdrv_common_block_status_above(BlockDriverState *bs, |
2412 | BlockDriverState *base, |
2413 | bool want_zero, int64_t offset, |
2414 | int64_t bytes, int64_t *pnum, |
2415 | int64_t *map, |
2416 | BlockDriverState **file) |
2417 | { |
2418 | Coroutine *co; |
2419 | BdrvCoBlockStatusData data = { |
2420 | .bs = bs, |
2421 | .base = base, |
2422 | .want_zero = want_zero, |
2423 | .offset = offset, |
2424 | .bytes = bytes, |
2425 | .pnum = pnum, |
2426 | .map = map, |
2427 | .file = file, |
2428 | .done = false, |
2429 | }; |
2430 | |
2431 | if (qemu_in_coroutine()) { |
2432 | /* Fast-path if already in coroutine context */ |
2433 | bdrv_block_status_above_co_entry(&data); |
2434 | } else { |
2435 | co = qemu_coroutine_create(bdrv_block_status_above_co_entry, &data); |
2436 | bdrv_coroutine_enter(bs, co); |
2437 | BDRV_POLL_WHILE(bs, !data.done); |
2438 | } |
2439 | return data.ret; |
2440 | } |
2441 | |
2442 | int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base, |
2443 | int64_t offset, int64_t bytes, int64_t *pnum, |
2444 | int64_t *map, BlockDriverState **file) |
2445 | { |
2446 | return bdrv_common_block_status_above(bs, base, true, offset, bytes, |
2447 | pnum, map, file); |
2448 | } |
2449 | |
2450 | int bdrv_block_status(BlockDriverState *bs, int64_t offset, int64_t bytes, |
2451 | int64_t *pnum, int64_t *map, BlockDriverState **file) |
2452 | { |
2453 | return bdrv_block_status_above(bs, backing_bs(bs), |
2454 | offset, bytes, pnum, map, file); |
2455 | } |
2456 | |
2457 | int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset, |
2458 | int64_t bytes, int64_t *pnum) |
2459 | { |
2460 | int ret; |
2461 | int64_t dummy; |
2462 | |
2463 | ret = bdrv_common_block_status_above(bs, backing_bs(bs), false, offset, |
2464 | bytes, pnum ? pnum : &dummy, NULL, |
2465 | NULL); |
2466 | if (ret < 0) { |
2467 | return ret; |
2468 | } |
2469 | return !!(ret & BDRV_BLOCK_ALLOCATED); |
2470 | } |
2471 | |
2472 | /* |
2473 | * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP] |
2474 | * |
2475 | * Return 1 if (a prefix of) the given range is allocated in any image |
2476 | * between BASE and TOP (BASE is only included if include_base is set). |
2477 | * BASE can be NULL to check if the given offset is allocated in any |
2478 | * image of the chain. Return 0 otherwise, or negative errno on |
2479 | * failure. |
2480 | * |
2481 | * 'pnum' is set to the number of bytes (including and immediately |
2482 | * following the specified offset) that are known to be in the same |
2483 | * allocated/unallocated state. Note that a subsequent call starting |
2484 | * at 'offset + *pnum' may return the same allocation status (in other |
2485 | * words, the result is not necessarily the maximum possible range); |
2486 | * but 'pnum' will only be 0 when end of file is reached. |
2487 | * |
2488 | */ |
2489 | int bdrv_is_allocated_above(BlockDriverState *top, |
2490 | BlockDriverState *base, |
2491 | bool include_base, int64_t offset, |
2492 | int64_t bytes, int64_t *pnum) |
2493 | { |
2494 | BlockDriverState *intermediate; |
2495 | int ret; |
2496 | int64_t n = bytes; |
2497 | |
2498 | assert(base || !include_base); |
2499 | |
2500 | intermediate = top; |
2501 | while (include_base || intermediate != base) { |
2502 | int64_t pnum_inter; |
2503 | int64_t size_inter; |
2504 | |
2505 | assert(intermediate); |
2506 | ret = bdrv_is_allocated(intermediate, offset, bytes, &pnum_inter); |
2507 | if (ret < 0) { |
2508 | return ret; |
2509 | } |
2510 | if (ret) { |
2511 | *pnum = pnum_inter; |
2512 | return 1; |
2513 | } |
2514 | |
2515 | size_inter = bdrv_getlength(intermediate); |
2516 | if (size_inter < 0) { |
2517 | return size_inter; |
2518 | } |
2519 | if (n > pnum_inter && |
2520 | (intermediate == top || offset + pnum_inter < size_inter)) { |
2521 | n = pnum_inter; |
2522 | } |
2523 | |
2524 | if (intermediate == base) { |
2525 | break; |
2526 | } |
2527 | |
2528 | intermediate = backing_bs(intermediate); |
2529 | } |
2530 | |
2531 | *pnum = n; |
2532 | return 0; |
2533 | } |
2534 | |
2535 | typedef struct BdrvVmstateCo { |
2536 | BlockDriverState *bs; |
2537 | QEMUIOVector *qiov; |
2538 | int64_t pos; |
2539 | bool is_read; |
2540 | int ret; |
2541 | } BdrvVmstateCo; |
2542 | |
2543 | static int coroutine_fn |
2544 | bdrv_co_rw_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos, |
2545 | bool is_read) |
2546 | { |
2547 | BlockDriver *drv = bs->drv; |
2548 | int ret = -ENOTSUP; |
2549 | |
2550 | bdrv_inc_in_flight(bs); |
2551 | |
2552 | if (!drv) { |
2553 | ret = -ENOMEDIUM; |
2554 | } else if (drv->bdrv_load_vmstate) { |
2555 | if (is_read) { |
2556 | ret = drv->bdrv_load_vmstate(bs, qiov, pos); |
2557 | } else { |
2558 | ret = drv->bdrv_save_vmstate(bs, qiov, pos); |
2559 | } |
2560 | } else if (bs->file) { |
2561 | ret = bdrv_co_rw_vmstate(bs->file->bs, qiov, pos, is_read); |
2562 | } |
2563 | |
2564 | bdrv_dec_in_flight(bs); |
2565 | return ret; |
2566 | } |
2567 | |
2568 | static void coroutine_fn bdrv_co_rw_vmstate_entry(void *opaque) |
2569 | { |
2570 | BdrvVmstateCo *co = opaque; |
2571 | co->ret = bdrv_co_rw_vmstate(co->bs, co->qiov, co->pos, co->is_read); |
2572 | aio_wait_kick(); |
2573 | } |
2574 | |
2575 | static inline int |
2576 | bdrv_rw_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos, |
2577 | bool is_read) |
2578 | { |
2579 | if (qemu_in_coroutine()) { |
2580 | return bdrv_co_rw_vmstate(bs, qiov, pos, is_read); |
2581 | } else { |
2582 | BdrvVmstateCo data = { |
2583 | .bs = bs, |
2584 | .qiov = qiov, |
2585 | .pos = pos, |
2586 | .is_read = is_read, |
2587 | .ret = -EINPROGRESS, |
2588 | }; |
2589 | Coroutine *co = qemu_coroutine_create(bdrv_co_rw_vmstate_entry, &data); |
2590 | |
2591 | bdrv_coroutine_enter(bs, co); |
2592 | BDRV_POLL_WHILE(bs, data.ret == -EINPROGRESS); |
2593 | return data.ret; |
2594 | } |
2595 | } |
2596 | |
2597 | int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf, |
2598 | int64_t pos, int size) |
2599 | { |
2600 | QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, size); |
2601 | int ret; |
2602 | |
2603 | ret = bdrv_writev_vmstate(bs, &qiov, pos); |
2604 | if (ret < 0) { |
2605 | return ret; |
2606 | } |
2607 | |
2608 | return size; |
2609 | } |
2610 | |
2611 | int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) |
2612 | { |
2613 | return bdrv_rw_vmstate(bs, qiov, pos, false); |
2614 | } |
2615 | |
2616 | int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf, |
2617 | int64_t pos, int size) |
2618 | { |
2619 | QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, size); |
2620 | int ret; |
2621 | |
2622 | ret = bdrv_readv_vmstate(bs, &qiov, pos); |
2623 | if (ret < 0) { |
2624 | return ret; |
2625 | } |
2626 | |
2627 | return size; |
2628 | } |
2629 | |
2630 | int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) |
2631 | { |
2632 | return bdrv_rw_vmstate(bs, qiov, pos, true); |
2633 | } |
2634 | |
2635 | /**************************************************************/ |
2636 | /* async I/Os */ |
2637 | |
2638 | void bdrv_aio_cancel(BlockAIOCB *acb) |
2639 | { |
2640 | qemu_aio_ref(acb); |
2641 | bdrv_aio_cancel_async(acb); |
2642 | while (acb->refcnt > 1) { |
2643 | if (acb->aiocb_info->get_aio_context) { |
2644 | aio_poll(acb->aiocb_info->get_aio_context(acb), true); |
2645 | } else if (acb->bs) { |
2646 | /* qemu_aio_ref and qemu_aio_unref are not thread-safe, so |
2647 | * assert that we're not using an I/O thread. Thread-safe |
2648 | * code should use bdrv_aio_cancel_async exclusively. |
2649 | */ |
2650 | assert(bdrv_get_aio_context(acb->bs) == qemu_get_aio_context()); |
2651 | aio_poll(bdrv_get_aio_context(acb->bs), true); |
2652 | } else { |
2653 | abort(); |
2654 | } |
2655 | } |
2656 | qemu_aio_unref(acb); |
2657 | } |
2658 | |
2659 | /* Async version of aio cancel. The caller is not blocked if the acb implements |
2660 | * cancel_async, otherwise we do nothing and let the request normally complete. |
2661 | * In either case the completion callback must be called. */ |
2662 | void bdrv_aio_cancel_async(BlockAIOCB *acb) |
2663 | { |
2664 | if (acb->aiocb_info->cancel_async) { |
2665 | acb->aiocb_info->cancel_async(acb); |
2666 | } |
2667 | } |
2668 | |
2669 | /**************************************************************/ |
2670 | /* Coroutine block device emulation */ |
2671 | |
2672 | typedef struct FlushCo { |
2673 | BlockDriverState *bs; |
2674 | int ret; |
2675 | } FlushCo; |
2676 | |
2677 | |
2678 | static void coroutine_fn bdrv_flush_co_entry(void *opaque) |
2679 | { |
2680 | FlushCo *rwco = opaque; |
2681 | |
2682 | rwco->ret = bdrv_co_flush(rwco->bs); |
2683 | aio_wait_kick(); |
2684 | } |
2685 | |
2686 | int coroutine_fn bdrv_co_flush(BlockDriverState *bs) |
2687 | { |
2688 | int current_gen; |
2689 | int ret = 0; |
2690 | |
2691 | bdrv_inc_in_flight(bs); |
2692 | |
2693 | if (!bdrv_is_inserted(bs) || bdrv_is_read_only(bs) || |
2694 | bdrv_is_sg(bs)) { |
2695 | goto early_exit; |
2696 | } |
2697 | |
2698 | qemu_co_mutex_lock(&bs->reqs_lock); |
2699 | current_gen = atomic_read(&bs->write_gen); |
2700 | |
2701 | /* Wait until any previous flushes are completed */ |
2702 | while (bs->active_flush_req) { |
2703 | qemu_co_queue_wait(&bs->flush_queue, &bs->reqs_lock); |
2704 | } |
2705 | |
2706 | /* Flushes reach this point in nondecreasing current_gen order. */ |
2707 | bs->active_flush_req = true; |
2708 | qemu_co_mutex_unlock(&bs->reqs_lock); |
2709 | |
2710 | /* Write back all layers by calling one driver function */ |
2711 | if (bs->drv->bdrv_co_flush) { |
2712 | ret = bs->drv->bdrv_co_flush(bs); |
2713 | goto out; |
2714 | } |
2715 | |
2716 | /* Write back cached data to the OS even with cache=unsafe */ |
2717 | BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS); |
2718 | if (bs->drv->bdrv_co_flush_to_os) { |
2719 | ret = bs->drv->bdrv_co_flush_to_os(bs); |
2720 | if (ret < 0) { |
2721 | goto out; |
2722 | } |
2723 | } |
2724 | |
2725 | /* But don't actually force it to the disk with cache=unsafe */ |
2726 | if (bs->open_flags & BDRV_O_NO_FLUSH) { |
2727 | goto flush_parent; |
2728 | } |
2729 | |
2730 | /* Check if we really need to flush anything */ |
2731 | if (bs->flushed_gen == current_gen) { |
2732 | goto flush_parent; |
2733 | } |
2734 | |
2735 | BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_DISK); |
2736 | if (!bs->drv) { |
2737 | /* bs->drv->bdrv_co_flush() might have ejected the BDS |
2738 | * (even in case of apparent success) */ |
2739 | ret = -ENOMEDIUM; |
2740 | goto out; |
2741 | } |
2742 | if (bs->drv->bdrv_co_flush_to_disk) { |
2743 | ret = bs->drv->bdrv_co_flush_to_disk(bs); |
2744 | } else if (bs->drv->bdrv_aio_flush) { |
2745 | BlockAIOCB *acb; |
2746 | CoroutineIOCompletion co = { |
2747 | .coroutine = qemu_coroutine_self(), |
2748 | }; |
2749 | |
2750 | acb = bs->drv->bdrv_aio_flush(bs, bdrv_co_io_em_complete, &co); |
2751 | if (acb == NULL) { |
2752 | ret = -EIO; |
2753 | } else { |
2754 | qemu_coroutine_yield(); |
2755 | ret = co.ret; |
2756 | } |
2757 | } else { |
2758 | /* |
2759 | * Some block drivers always operate in either writethrough or unsafe |
2760 | * mode and don't support bdrv_flush therefore. Usually qemu doesn't |
2761 | * know how the server works (because the behaviour is hardcoded or |
2762 | * depends on server-side configuration), so we can't ensure that |
2763 | * everything is safe on disk. Returning an error doesn't work because |
2764 | * that would break guests even if the server operates in writethrough |
2765 | * mode. |
2766 | * |
2767 | * Let's hope the user knows what he's doing. |
2768 | */ |
2769 | ret = 0; |
2770 | } |
2771 | |
2772 | if (ret < 0) { |
2773 | goto out; |
2774 | } |
2775 | |
2776 | /* Now flush the underlying protocol. It will also have BDRV_O_NO_FLUSH |
2777 | * in the case of cache=unsafe, so there are no useless flushes. |
2778 | */ |
2779 | flush_parent: |
2780 | ret = bs->file ? bdrv_co_flush(bs->file->bs) : 0; |
2781 | out: |
2782 | /* Notify any pending flushes that we have completed */ |
2783 | if (ret == 0) { |
2784 | bs->flushed_gen = current_gen; |
2785 | } |
2786 | |
2787 | qemu_co_mutex_lock(&bs->reqs_lock); |
2788 | bs->active_flush_req = false; |
2789 | /* Return value is ignored - it's ok if wait queue is empty */ |
2790 | qemu_co_queue_next(&bs->flush_queue); |
2791 | qemu_co_mutex_unlock(&bs->reqs_lock); |
2792 | |
2793 | early_exit: |
2794 | bdrv_dec_in_flight(bs); |
2795 | return ret; |
2796 | } |
2797 | |
2798 | int bdrv_flush(BlockDriverState *bs) |
2799 | { |
2800 | Coroutine *co; |
2801 | FlushCo flush_co = { |
2802 | .bs = bs, |
2803 | .ret = NOT_DONE, |
2804 | }; |
2805 | |
2806 | if (qemu_in_coroutine()) { |
2807 | /* Fast-path if already in coroutine context */ |
2808 | bdrv_flush_co_entry(&flush_co); |
2809 | } else { |
2810 | co = qemu_coroutine_create(bdrv_flush_co_entry, &flush_co); |
2811 | bdrv_coroutine_enter(bs, co); |
2812 | BDRV_POLL_WHILE(bs, flush_co.ret == NOT_DONE); |
2813 | } |
2814 | |
2815 | return flush_co.ret; |
2816 | } |
2817 | |
2818 | typedef struct DiscardCo { |
2819 | BdrvChild *child; |
2820 | int64_t offset; |
2821 | int64_t bytes; |
2822 | int ret; |
2823 | } DiscardCo; |
2824 | static void coroutine_fn bdrv_pdiscard_co_entry(void *opaque) |
2825 | { |
2826 | DiscardCo *rwco = opaque; |
2827 | |
2828 | rwco->ret = bdrv_co_pdiscard(rwco->child, rwco->offset, rwco->bytes); |
2829 | aio_wait_kick(); |
2830 | } |
2831 | |
2832 | int coroutine_fn bdrv_co_pdiscard(BdrvChild *child, int64_t offset, |
2833 | int64_t bytes) |
2834 | { |
2835 | BdrvTrackedRequest req; |
2836 | int max_pdiscard, ret; |
2837 | int head, tail, align; |
2838 | BlockDriverState *bs = child->bs; |
2839 | |
2840 | if (!bs || !bs->drv || !bdrv_is_inserted(bs)) { |
2841 | return -ENOMEDIUM; |
2842 | } |
2843 | |
2844 | if (bdrv_has_readonly_bitmaps(bs)) { |
2845 | return -EPERM; |
2846 | } |
2847 | |
2848 | if (offset < 0 || bytes < 0 || bytes > INT64_MAX - offset) { |
2849 | return -EIO; |
2850 | } |
2851 | |
2852 | /* Do nothing if disabled. */ |
2853 | if (!(bs->open_flags & BDRV_O_UNMAP)) { |
2854 | return 0; |
2855 | } |
2856 | |
2857 | if (!bs->drv->bdrv_co_pdiscard && !bs->drv->bdrv_aio_pdiscard) { |
2858 | return 0; |
2859 | } |
2860 | |
2861 | /* Discard is advisory, but some devices track and coalesce |
2862 | * unaligned requests, so we must pass everything down rather than |
2863 | * round here. Still, most devices will just silently ignore |
2864 | * unaligned requests (by returning -ENOTSUP), so we must fragment |
2865 | * the request accordingly. */ |
2866 | align = MAX(bs->bl.pdiscard_alignment, bs->bl.request_alignment); |
2867 | assert(align % bs->bl.request_alignment == 0); |
2868 | head = offset % align; |
2869 | tail = (offset + bytes) % align; |
2870 | |
2871 | bdrv_inc_in_flight(bs); |
2872 | tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_DISCARD); |
2873 | |
2874 | ret = bdrv_co_write_req_prepare(child, offset, bytes, &req, 0); |
2875 | if (ret < 0) { |
2876 | goto out; |
2877 | } |
2878 | |
2879 | max_pdiscard = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_pdiscard, INT_MAX), |
2880 | align); |
2881 | assert(max_pdiscard >= bs->bl.request_alignment); |
2882 | |
2883 | while (bytes > 0) { |
2884 | int64_t num = bytes; |
2885 | |
2886 | if (head) { |
2887 | /* Make small requests to get to alignment boundaries. */ |
2888 | num = MIN(bytes, align - head); |
2889 | if (!QEMU_IS_ALIGNED(num, bs->bl.request_alignment)) { |
2890 | num %= bs->bl.request_alignment; |
2891 | } |
2892 | head = (head + num) % align; |
2893 | assert(num < max_pdiscard); |
2894 | } else if (tail) { |
2895 | if (num > align) { |
2896 | /* Shorten the request to the last aligned cluster. */ |
2897 | num -= tail; |
2898 | } else if (!QEMU_IS_ALIGNED(tail, bs->bl.request_alignment) && |
2899 | tail > bs->bl.request_alignment) { |
2900 | tail %= bs->bl.request_alignment; |
2901 | num -= tail; |
2902 | } |
2903 | } |
2904 | /* limit request size */ |
2905 | if (num > max_pdiscard) { |
2906 | num = max_pdiscard; |
2907 | } |
2908 | |
2909 | if (!bs->drv) { |
2910 | ret = -ENOMEDIUM; |
2911 | goto out; |
2912 | } |
2913 | if (bs->drv->bdrv_co_pdiscard) { |
2914 | ret = bs->drv->bdrv_co_pdiscard(bs, offset, num); |
2915 | } else { |
2916 | BlockAIOCB *acb; |
2917 | CoroutineIOCompletion co = { |
2918 | .coroutine = qemu_coroutine_self(), |
2919 | }; |
2920 | |
2921 | acb = bs->drv->bdrv_aio_pdiscard(bs, offset, num, |
2922 | bdrv_co_io_em_complete, &co); |
2923 | if (acb == NULL) { |
2924 | ret = -EIO; |
2925 | goto out; |
2926 | } else { |
2927 | qemu_coroutine_yield(); |
2928 | ret = co.ret; |
2929 | } |
2930 | } |
2931 | if (ret && ret != -ENOTSUP) { |
2932 | goto out; |
2933 | } |
2934 | |
2935 | offset += num; |
2936 | bytes -= num; |
2937 | } |
2938 | ret = 0; |
2939 | out: |
2940 | bdrv_co_write_req_finish(child, req.offset, req.bytes, &req, ret); |
2941 | tracked_request_end(&req); |
2942 | bdrv_dec_in_flight(bs); |
2943 | return ret; |
2944 | } |
2945 | |
2946 | int bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes) |
2947 | { |
2948 | Coroutine *co; |
2949 | DiscardCo rwco = { |
2950 | .child = child, |
2951 | .offset = offset, |
2952 | .bytes = bytes, |
2953 | .ret = NOT_DONE, |
2954 | }; |
2955 | |
2956 | if (qemu_in_coroutine()) { |
2957 | /* Fast-path if already in coroutine context */ |
2958 | bdrv_pdiscard_co_entry(&rwco); |
2959 | } else { |
2960 | co = qemu_coroutine_create(bdrv_pdiscard_co_entry, &rwco); |
2961 | bdrv_coroutine_enter(child->bs, co); |
2962 | BDRV_POLL_WHILE(child->bs, rwco.ret == NOT_DONE); |
2963 | } |
2964 | |
2965 | return rwco.ret; |
2966 | } |
2967 | |
2968 | int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf) |
2969 | { |
2970 | BlockDriver *drv = bs->drv; |
2971 | CoroutineIOCompletion co = { |
2972 | .coroutine = qemu_coroutine_self(), |
2973 | }; |
2974 | BlockAIOCB *acb; |
2975 | |
2976 | bdrv_inc_in_flight(bs); |
2977 | if (!drv || (!drv->bdrv_aio_ioctl && !drv->bdrv_co_ioctl)) { |
2978 | co.ret = -ENOTSUP; |
2979 | goto out; |
2980 | } |
2981 | |
2982 | if (drv->bdrv_co_ioctl) { |
2983 | co.ret = drv->bdrv_co_ioctl(bs, req, buf); |
2984 | } else { |
2985 | acb = drv->bdrv_aio_ioctl(bs, req, buf, bdrv_co_io_em_complete, &co); |
2986 | if (!acb) { |
2987 | co.ret = -ENOTSUP; |
2988 | goto out; |
2989 | } |
2990 | qemu_coroutine_yield(); |
2991 | } |
2992 | out: |
2993 | bdrv_dec_in_flight(bs); |
2994 | return co.ret; |
2995 | } |
2996 | |
2997 | void *qemu_blockalign(BlockDriverState *bs, size_t size) |
2998 | { |
2999 | return qemu_memalign(bdrv_opt_mem_align(bs), size); |
3000 | } |
3001 | |
3002 | void *qemu_blockalign0(BlockDriverState *bs, size_t size) |
3003 | { |
3004 | return memset(qemu_blockalign(bs, size), 0, size); |
3005 | } |
3006 | |
3007 | void *qemu_try_blockalign(BlockDriverState *bs, size_t size) |
3008 | { |
3009 | size_t align = bdrv_opt_mem_align(bs); |
3010 | |
3011 | /* Ensure that NULL is never returned on success */ |
3012 | assert(align > 0); |
3013 | if (size == 0) { |
3014 | size = align; |
3015 | } |
3016 | |
3017 | return qemu_try_memalign(align, size); |
3018 | } |
3019 | |
3020 | void *qemu_try_blockalign0(BlockDriverState *bs, size_t size) |
3021 | { |
3022 | void *mem = qemu_try_blockalign(bs, size); |
3023 | |
3024 | if (mem) { |
3025 | memset(mem, 0, size); |
3026 | } |
3027 | |
3028 | return mem; |
3029 | } |
3030 | |
3031 | /* |
3032 | * Check if all memory in this vector is sector aligned. |
3033 | */ |
3034 | bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov) |
3035 | { |
3036 | int i; |
3037 | size_t alignment = bdrv_min_mem_align(bs); |
3038 | |
3039 | for (i = 0; i < qiov->niov; i++) { |
3040 | if ((uintptr_t) qiov->iov[i].iov_base % alignment) { |
3041 | return false; |
3042 | } |
3043 | if (qiov->iov[i].iov_len % alignment) { |
3044 | return false; |
3045 | } |
3046 | } |
3047 | |
3048 | return true; |
3049 | } |
3050 | |
3051 | void bdrv_add_before_write_notifier(BlockDriverState *bs, |
3052 | NotifierWithReturn *notifier) |
3053 | { |
3054 | notifier_with_return_list_add(&bs->before_write_notifiers, notifier); |
3055 | } |
3056 | |
3057 | void bdrv_io_plug(BlockDriverState *bs) |
3058 | { |
3059 | BdrvChild *child; |
3060 | |
3061 | QLIST_FOREACH(child, &bs->children, next) { |
3062 | bdrv_io_plug(child->bs); |
3063 | } |
3064 | |
3065 | if (atomic_fetch_inc(&bs->io_plugged) == 0) { |
3066 | BlockDriver *drv = bs->drv; |
3067 | if (drv && drv->bdrv_io_plug) { |
3068 | drv->bdrv_io_plug(bs); |
3069 | } |
3070 | } |
3071 | } |
3072 | |
3073 | void bdrv_io_unplug(BlockDriverState *bs) |
3074 | { |
3075 | BdrvChild *child; |
3076 | |
3077 | assert(bs->io_plugged); |
3078 | if (atomic_fetch_dec(&bs->io_plugged) == 1) { |
3079 | BlockDriver *drv = bs->drv; |
3080 | if (drv && drv->bdrv_io_unplug) { |
3081 | drv->bdrv_io_unplug(bs); |
3082 | } |
3083 | } |
3084 | |
3085 | QLIST_FOREACH(child, &bs->children, next) { |
3086 | bdrv_io_unplug(child->bs); |
3087 | } |
3088 | } |
3089 | |
3090 | void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size) |
3091 | { |
3092 | BdrvChild *child; |
3093 | |
3094 | if (bs->drv && bs->drv->bdrv_register_buf) { |
3095 | bs->drv->bdrv_register_buf(bs, host, size); |
3096 | } |
3097 | QLIST_FOREACH(child, &bs->children, next) { |
3098 | bdrv_register_buf(child->bs, host, size); |
3099 | } |
3100 | } |
3101 | |
3102 | void bdrv_unregister_buf(BlockDriverState *bs, void *host) |
3103 | { |
3104 | BdrvChild *child; |
3105 | |
3106 | if (bs->drv && bs->drv->bdrv_unregister_buf) { |
3107 | bs->drv->bdrv_unregister_buf(bs, host); |
3108 | } |
3109 | QLIST_FOREACH(child, &bs->children, next) { |
3110 | bdrv_unregister_buf(child->bs, host); |
3111 | } |
3112 | } |
3113 | |
3114 | static int coroutine_fn bdrv_co_copy_range_internal( |
3115 | BdrvChild *src, uint64_t src_offset, BdrvChild *dst, |
3116 | uint64_t dst_offset, uint64_t bytes, |
3117 | BdrvRequestFlags read_flags, BdrvRequestFlags write_flags, |
3118 | bool recurse_src) |
3119 | { |
3120 | BdrvTrackedRequest req; |
3121 | int ret; |
3122 | |
3123 | /* TODO We can support BDRV_REQ_NO_FALLBACK here */ |
3124 | assert(!(read_flags & BDRV_REQ_NO_FALLBACK)); |
3125 | assert(!(write_flags & BDRV_REQ_NO_FALLBACK)); |
3126 | |
3127 | if (!dst || !dst->bs) { |
3128 | return -ENOMEDIUM; |
3129 | } |
3130 | ret = bdrv_check_byte_request(dst->bs, dst_offset, bytes); |
3131 | if (ret) { |
3132 | return ret; |
3133 | } |
3134 | if (write_flags & BDRV_REQ_ZERO_WRITE) { |
3135 | return bdrv_co_pwrite_zeroes(dst, dst_offset, bytes, write_flags); |
3136 | } |
3137 | |
3138 | if (!src || !src->bs) { |
3139 | return -ENOMEDIUM; |
3140 | } |
3141 | ret = bdrv_check_byte_request(src->bs, src_offset, bytes); |
3142 | if (ret) { |
3143 | return ret; |
3144 | } |
3145 | |
3146 | if (!src->bs->drv->bdrv_co_copy_range_from |
3147 | || !dst->bs->drv->bdrv_co_copy_range_to |
3148 | || src->bs->encrypted || dst->bs->encrypted) { |
3149 | return -ENOTSUP; |
3150 | } |
3151 | |
3152 | if (recurse_src) { |
3153 | bdrv_inc_in_flight(src->bs); |
3154 | tracked_request_begin(&req, src->bs, src_offset, bytes, |
3155 | BDRV_TRACKED_READ); |
3156 | |
3157 | /* BDRV_REQ_SERIALISING is only for write operation */ |
3158 | assert(!(read_flags & BDRV_REQ_SERIALISING)); |
3159 | if (!(read_flags & BDRV_REQ_NO_SERIALISING)) { |
3160 | wait_serialising_requests(&req); |
3161 | } |
3162 | |
3163 | ret = src->bs->drv->bdrv_co_copy_range_from(src->bs, |
3164 | src, src_offset, |
3165 | dst, dst_offset, |
3166 | bytes, |
3167 | read_flags, write_flags); |
3168 | |
3169 | tracked_request_end(&req); |
3170 | bdrv_dec_in_flight(src->bs); |
3171 | } else { |
3172 | bdrv_inc_in_flight(dst->bs); |
3173 | tracked_request_begin(&req, dst->bs, dst_offset, bytes, |
3174 | BDRV_TRACKED_WRITE); |
3175 | ret = bdrv_co_write_req_prepare(dst, dst_offset, bytes, &req, |
3176 | write_flags); |
3177 | if (!ret) { |
3178 | ret = dst->bs->drv->bdrv_co_copy_range_to(dst->bs, |
3179 | src, src_offset, |
3180 | dst, dst_offset, |
3181 | bytes, |
3182 | read_flags, write_flags); |
3183 | } |
3184 | bdrv_co_write_req_finish(dst, dst_offset, bytes, &req, ret); |
3185 | tracked_request_end(&req); |
3186 | bdrv_dec_in_flight(dst->bs); |
3187 | } |
3188 | |
3189 | return ret; |
3190 | } |
3191 | |
3192 | /* Copy range from @src to @dst. |
3193 | * |
3194 | * See the comment of bdrv_co_copy_range for the parameter and return value |
3195 | * semantics. */ |
3196 | int coroutine_fn bdrv_co_copy_range_from(BdrvChild *src, uint64_t src_offset, |
3197 | BdrvChild *dst, uint64_t dst_offset, |
3198 | uint64_t bytes, |
3199 | BdrvRequestFlags read_flags, |
3200 | BdrvRequestFlags write_flags) |
3201 | { |
3202 | trace_bdrv_co_copy_range_from(src, src_offset, dst, dst_offset, bytes, |
3203 | read_flags, write_flags); |
3204 | return bdrv_co_copy_range_internal(src, src_offset, dst, dst_offset, |
3205 | bytes, read_flags, write_flags, true); |
3206 | } |
3207 | |
3208 | /* Copy range from @src to @dst. |
3209 | * |
3210 | * See the comment of bdrv_co_copy_range for the parameter and return value |
3211 | * semantics. */ |
3212 | int coroutine_fn bdrv_co_copy_range_to(BdrvChild *src, uint64_t src_offset, |
3213 | BdrvChild *dst, uint64_t dst_offset, |
3214 | uint64_t bytes, |
3215 | BdrvRequestFlags read_flags, |
3216 | BdrvRequestFlags write_flags) |
3217 | { |
3218 | trace_bdrv_co_copy_range_to(src, src_offset, dst, dst_offset, bytes, |
3219 | read_flags, write_flags); |
3220 | return bdrv_co_copy_range_internal(src, src_offset, dst, dst_offset, |
3221 | bytes, read_flags, write_flags, false); |
3222 | } |
3223 | |
3224 | int coroutine_fn bdrv_co_copy_range(BdrvChild *src, uint64_t src_offset, |
3225 | BdrvChild *dst, uint64_t dst_offset, |
3226 | uint64_t bytes, BdrvRequestFlags read_flags, |
3227 | BdrvRequestFlags write_flags) |
3228 | { |
3229 | return bdrv_co_copy_range_from(src, src_offset, |
3230 | dst, dst_offset, |
3231 | bytes, read_flags, write_flags); |
3232 | } |
3233 | |
3234 | static void bdrv_parent_cb_resize(BlockDriverState *bs) |
3235 | { |
3236 | BdrvChild *c; |
3237 | QLIST_FOREACH(c, &bs->parents, next_parent) { |
3238 | if (c->role->resize) { |
3239 | c->role->resize(c); |
3240 | } |
3241 | } |
3242 | } |
3243 | |
3244 | /** |
3245 | * Truncate file to 'offset' bytes (needed only for file protocols) |
3246 | */ |
3247 | int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, |
3248 | PreallocMode prealloc, Error **errp) |
3249 | { |
3250 | BlockDriverState *bs = child->bs; |
3251 | BlockDriver *drv = bs->drv; |
3252 | BdrvTrackedRequest req; |
3253 | int64_t old_size, new_bytes; |
3254 | int ret; |
3255 | |
3256 | |
3257 | /* if bs->drv == NULL, bs is closed, so there's nothing to do here */ |
3258 | if (!drv) { |
3259 | error_setg(errp, "No medium inserted" ); |
3260 | return -ENOMEDIUM; |
3261 | } |
3262 | if (offset < 0) { |
3263 | error_setg(errp, "Image size cannot be negative" ); |
3264 | return -EINVAL; |
3265 | } |
3266 | |
3267 | old_size = bdrv_getlength(bs); |
3268 | if (old_size < 0) { |
3269 | error_setg_errno(errp, -old_size, "Failed to get old image size" ); |
3270 | return old_size; |
3271 | } |
3272 | |
3273 | if (offset > old_size) { |
3274 | new_bytes = offset - old_size; |
3275 | } else { |
3276 | new_bytes = 0; |
3277 | } |
3278 | |
3279 | bdrv_inc_in_flight(bs); |
3280 | tracked_request_begin(&req, bs, offset - new_bytes, new_bytes, |
3281 | BDRV_TRACKED_TRUNCATE); |
3282 | |
3283 | /* If we are growing the image and potentially using preallocation for the |
3284 | * new area, we need to make sure that no write requests are made to it |
3285 | * concurrently or they might be overwritten by preallocation. */ |
3286 | if (new_bytes) { |
3287 | mark_request_serialising(&req, 1); |
3288 | } |
3289 | if (bs->read_only) { |
3290 | error_setg(errp, "Image is read-only" ); |
3291 | ret = -EACCES; |
3292 | goto out; |
3293 | } |
3294 | ret = bdrv_co_write_req_prepare(child, offset - new_bytes, new_bytes, &req, |
3295 | 0); |
3296 | if (ret < 0) { |
3297 | error_setg_errno(errp, -ret, |
3298 | "Failed to prepare request for truncation" ); |
3299 | goto out; |
3300 | } |
3301 | |
3302 | if (!drv->bdrv_co_truncate) { |
3303 | if (bs->file && drv->is_filter) { |
3304 | ret = bdrv_co_truncate(bs->file, offset, prealloc, errp); |
3305 | goto out; |
3306 | } |
3307 | error_setg(errp, "Image format driver does not support resize" ); |
3308 | ret = -ENOTSUP; |
3309 | goto out; |
3310 | } |
3311 | |
3312 | ret = drv->bdrv_co_truncate(bs, offset, prealloc, errp); |
3313 | if (ret < 0) { |
3314 | goto out; |
3315 | } |
3316 | ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS); |
3317 | if (ret < 0) { |
3318 | error_setg_errno(errp, -ret, "Could not refresh total sector count" ); |
3319 | } else { |
3320 | offset = bs->total_sectors * BDRV_SECTOR_SIZE; |
3321 | } |
3322 | /* It's possible that truncation succeeded but refresh_total_sectors |
3323 | * failed, but the latter doesn't affect how we should finish the request. |
3324 | * Pass 0 as the last parameter so that dirty bitmaps etc. are handled. */ |
3325 | bdrv_co_write_req_finish(child, offset - new_bytes, new_bytes, &req, 0); |
3326 | |
3327 | out: |
3328 | tracked_request_end(&req); |
3329 | bdrv_dec_in_flight(bs); |
3330 | |
3331 | return ret; |
3332 | } |
3333 | |
3334 | typedef struct TruncateCo { |
3335 | BdrvChild *child; |
3336 | int64_t offset; |
3337 | PreallocMode prealloc; |
3338 | Error **errp; |
3339 | int ret; |
3340 | } TruncateCo; |
3341 | |
3342 | static void coroutine_fn bdrv_truncate_co_entry(void *opaque) |
3343 | { |
3344 | TruncateCo *tco = opaque; |
3345 | tco->ret = bdrv_co_truncate(tco->child, tco->offset, tco->prealloc, |
3346 | tco->errp); |
3347 | aio_wait_kick(); |
3348 | } |
3349 | |
3350 | int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc, |
3351 | Error **errp) |
3352 | { |
3353 | Coroutine *co; |
3354 | TruncateCo tco = { |
3355 | .child = child, |
3356 | .offset = offset, |
3357 | .prealloc = prealloc, |
3358 | .errp = errp, |
3359 | .ret = NOT_DONE, |
3360 | }; |
3361 | |
3362 | if (qemu_in_coroutine()) { |
3363 | /* Fast-path if already in coroutine context */ |
3364 | bdrv_truncate_co_entry(&tco); |
3365 | } else { |
3366 | co = qemu_coroutine_create(bdrv_truncate_co_entry, &tco); |
3367 | bdrv_coroutine_enter(child->bs, co); |
3368 | BDRV_POLL_WHILE(child->bs, tco.ret == NOT_DONE); |
3369 | } |
3370 | |
3371 | return tco.ret; |
3372 | } |
3373 | |