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qcow2: Remove unnecessary flush after L2 write
[qemu/qemu-dev-zwu.git] / block.c
bloba5514e361ae6e979f53c22e6e8c5b3ff4e6600c8
1 /*
2 * QEMU System Emulator block driver
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 #include "config-host.h"
25 #include "qemu-common.h"
26 #include "monitor.h"
27 #include "block_int.h"
28 #include "module.h"
29 #include "qemu-objects.h"
30
31 #ifdef CONFIG_BSD
32 #include <sys/types.h>
33 #include <sys/stat.h>
34 #include <sys/ioctl.h>
35 #include <sys/queue.h>
36 #ifndef __DragonFly__
37 #include <sys/disk.h>
38 #endif
39 #endif
40
41 #ifdef _WIN32
42 #include <windows.h>
43 #endif
44
45 static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs,
46 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
47 BlockDriverCompletionFunc *cb, void *opaque);
48 static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs,
49 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
50 BlockDriverCompletionFunc *cb, void *opaque);
51 static BlockDriverAIOCB *bdrv_aio_flush_em(BlockDriverState *bs,
52 BlockDriverCompletionFunc *cb, void *opaque);
53 static BlockDriverAIOCB *bdrv_aio_noop_em(BlockDriverState *bs,
54 BlockDriverCompletionFunc *cb, void *opaque);
55 static int bdrv_read_em(BlockDriverState *bs, int64_t sector_num,
56 uint8_t *buf, int nb_sectors);
57 static int bdrv_write_em(BlockDriverState *bs, int64_t sector_num,
58 const uint8_t *buf, int nb_sectors);
59
60 static QTAILQ_HEAD(, BlockDriverState) bdrv_states =
61 QTAILQ_HEAD_INITIALIZER(bdrv_states);
62
63 static QLIST_HEAD(, BlockDriver) bdrv_drivers =
64 QLIST_HEAD_INITIALIZER(bdrv_drivers);
65
66 /* The device to use for VM snapshots */
67 static BlockDriverState *bs_snapshots;
68
69 /* If non-zero, use only whitelisted block drivers */
70 static int use_bdrv_whitelist;
71
72 int path_is_absolute(const char *path)
73 {
74 const char *p;
75 #ifdef _WIN32
76 /* specific case for names like: "\\.\d:" */
77 if (*path == '/' || *path == '\\')
78 return 1;
79 #endif
80 p = strchr(path, ':');
81 if (p)
82 p++;
83 else
84 p = path;
85 #ifdef _WIN32
86 return (*p == '/' || *p == '\\');
87 #else
88 return (*p == '/');
89 #endif
90 }
91
92 /* if filename is absolute, just copy it to dest. Otherwise, build a
93 path to it by considering it is relative to base_path. URL are
94 supported. */
95 void path_combine(char *dest, int dest_size,
96 const char *base_path,
97 const char *filename)
98 {
99 const char *p, *p1;
100 int len;
101
102 if (dest_size <= 0)
103 return;
104 if (path_is_absolute(filename)) {
105 pstrcpy(dest, dest_size, filename);
106 } else {
107 p = strchr(base_path, ':');
108 if (p)
109 p++;
110 else
111 p = base_path;
112 p1 = strrchr(base_path, '/');
113 #ifdef _WIN32
114 {
115 const char *p2;
116 p2 = strrchr(base_path, '\\');
117 if (!p1 || p2 > p1)
118 p1 = p2;
119 }
120 #endif
121 if (p1)
122 p1++;
123 else
124 p1 = base_path;
125 if (p1 > p)
126 p = p1;
127 len = p - base_path;
128 if (len > dest_size - 1)
129 len = dest_size - 1;
130 memcpy(dest, base_path, len);
131 dest[len] = '\0';
132 pstrcat(dest, dest_size, filename);
133 }
134 }
135
136 void bdrv_register(BlockDriver *bdrv)
137 {
138 if (!bdrv->bdrv_aio_readv) {
139 /* add AIO emulation layer */
140 bdrv->bdrv_aio_readv = bdrv_aio_readv_em;
141 bdrv->bdrv_aio_writev = bdrv_aio_writev_em;
142 } else if (!bdrv->bdrv_read) {
143 /* add synchronous IO emulation layer */
144 bdrv->bdrv_read = bdrv_read_em;
145 bdrv->bdrv_write = bdrv_write_em;
146 }
147
148 if (!bdrv->bdrv_aio_flush)
149 bdrv->bdrv_aio_flush = bdrv_aio_flush_em;
150
151 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list);
152 }
153
154 /* create a new block device (by default it is empty) */
155 BlockDriverState *bdrv_new(const char *device_name)
156 {
157 BlockDriverState *bs;
158
159 bs = qemu_mallocz(sizeof(BlockDriverState));
160 pstrcpy(bs->device_name, sizeof(bs->device_name), device_name);
161 if (device_name[0] != '\0') {
162 QTAILQ_INSERT_TAIL(&bdrv_states, bs, list);
163 }
164 return bs;
165 }
166
167 BlockDriver *bdrv_find_format(const char *format_name)
168 {
169 BlockDriver *drv1;
170 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
171 if (!strcmp(drv1->format_name, format_name)) {
172 return drv1;
173 }
174 }
175 return NULL;
176 }
177
178 static int bdrv_is_whitelisted(BlockDriver *drv)
179 {
180 static const char *whitelist[] = {
181 CONFIG_BDRV_WHITELIST
182 };
183 const char **p;
184
185 if (!whitelist[0])
186 return 1; /* no whitelist, anything goes */
187
188 for (p = whitelist; *p; p++) {
189 if (!strcmp(drv->format_name, *p)) {
190 return 1;
191 }
192 }
193 return 0;
194 }
195
196 BlockDriver *bdrv_find_whitelisted_format(const char *format_name)
197 {
198 BlockDriver *drv = bdrv_find_format(format_name);
199 return drv && bdrv_is_whitelisted(drv) ? drv : NULL;
200 }
201
202 int bdrv_create(BlockDriver *drv, const char* filename,
203 QEMUOptionParameter *options)
204 {
205 if (!drv->bdrv_create)
206 return -ENOTSUP;
207
208 return drv->bdrv_create(filename, options);
209 }
210
211 int bdrv_create_file(const char* filename, QEMUOptionParameter *options)
212 {
213 BlockDriver *drv;
214
215 drv = bdrv_find_protocol(filename);
216 if (drv == NULL) {
217 drv = bdrv_find_format("file");
218 }
219
220 return bdrv_create(drv, filename, options);
221 }
222
223 #ifdef _WIN32
224 void get_tmp_filename(char *filename, int size)
225 {
226 char temp_dir[MAX_PATH];
227
228 GetTempPath(MAX_PATH, temp_dir);
229 GetTempFileName(temp_dir, "qem", 0, filename);
230 }
231 #else
232 void get_tmp_filename(char *filename, int size)
233 {
234 int fd;
235 const char *tmpdir;
236 /* XXX: race condition possible */
237 tmpdir = getenv("TMPDIR");
238 if (!tmpdir)
239 tmpdir = "/tmp";
240 snprintf(filename, size, "%s/vl.XXXXXX", tmpdir);
241 fd = mkstemp(filename);
242 close(fd);
243 }
244 #endif
245
246 #ifdef _WIN32
247 static int is_windows_drive_prefix(const char *filename)
248 {
249 return (((filename[0] >= 'a' && filename[0] <= 'z') ||
250 (filename[0] >= 'A' && filename[0] <= 'Z')) &&
251 filename[1] == ':');
252 }
253
254 int is_windows_drive(const char *filename)
255 {
256 if (is_windows_drive_prefix(filename) &&
257 filename[2] == '\0')
258 return 1;
259 if (strstart(filename, "\\\\.\\", NULL) ||
260 strstart(filename, "//./", NULL))
261 return 1;
262 return 0;
263 }
264 #endif
265
266 /*
267 * Detect host devices. By convention, /dev/cdrom[N] is always
268 * recognized as a host CDROM.
269 */
270 static BlockDriver *find_hdev_driver(const char *filename)
271 {
272 int score_max = 0, score;
273 BlockDriver *drv = NULL, *d;
274
275 QLIST_FOREACH(d, &bdrv_drivers, list) {
276 if (d->bdrv_probe_device) {
277 score = d->bdrv_probe_device(filename);
278 if (score > score_max) {
279 score_max = score;
280 drv = d;
281 }
282 }
283 }
284
285 return drv;
286 }
287
288 BlockDriver *bdrv_find_protocol(const char *filename)
289 {
290 BlockDriver *drv1;
291 char protocol[128];
292 int len;
293 const char *p;
294
295 /* TODO Drivers without bdrv_file_open must be specified explicitly */
296
297 /*
298 * XXX(hch): we really should not let host device detection
299 * override an explicit protocol specification, but moving this
300 * later breaks access to device names with colons in them.
301 * Thanks to the brain-dead persistent naming schemes on udev-
302 * based Linux systems those actually are quite common.
303 */
304 drv1 = find_hdev_driver(filename);
305 if (drv1) {
306 return drv1;
307 }
308
309 #ifdef _WIN32
310 if (is_windows_drive(filename) ||
311 is_windows_drive_prefix(filename))
312 return bdrv_find_format("file");
313 #endif
314
315 p = strchr(filename, ':');
316 if (!p) {
317 return bdrv_find_format("file");
318 }
319 len = p - filename;
320 if (len > sizeof(protocol) - 1)
321 len = sizeof(protocol) - 1;
322 memcpy(protocol, filename, len);
323 protocol[len] = '\0';
324 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
325 if (drv1->protocol_name &&
326 !strcmp(drv1->protocol_name, protocol)) {
327 return drv1;
328 }
329 }
330 return NULL;
331 }
332
333 static int find_image_format(const char *filename, BlockDriver **pdrv)
334 {
335 int ret, score, score_max;
336 BlockDriver *drv1, *drv;
337 uint8_t buf[2048];
338 BlockDriverState *bs;
339
340 ret = bdrv_file_open(&bs, filename, 0);
341 if (ret < 0) {
342 *pdrv = NULL;
343 return ret;
344 }
345
346 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
347 if (bs->sg || !bdrv_is_inserted(bs)) {
348 bdrv_delete(bs);
349 drv = bdrv_find_format("raw");
350 if (!drv) {
351 ret = -ENOENT;
352 }
353 *pdrv = drv;
354 return ret;
355 }
356
357 ret = bdrv_pread(bs, 0, buf, sizeof(buf));
358 bdrv_delete(bs);
359 if (ret < 0) {
360 *pdrv = NULL;
361 return ret;
362 }
363
364 score_max = 0;
365 drv = NULL;
366 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
367 if (drv1->bdrv_probe) {
368 score = drv1->bdrv_probe(buf, ret, filename);
369 if (score > score_max) {
370 score_max = score;
371 drv = drv1;
372 }
373 }
374 }
375 if (!drv) {
376 ret = -ENOENT;
377 }
378 *pdrv = drv;
379 return ret;
380 }
381
382 /**
383 * Set the current 'total_sectors' value
384 */
385 static int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
386 {
387 BlockDriver *drv = bs->drv;
388
389 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
390 if (bs->sg)
391 return 0;
392
393 /* query actual device if possible, otherwise just trust the hint */
394 if (drv->bdrv_getlength) {
395 int64_t length = drv->bdrv_getlength(bs);
396 if (length < 0) {
397 return length;
398 }
399 hint = length >> BDRV_SECTOR_BITS;
400 }
401
402 bs->total_sectors = hint;
403 return 0;
404 }
405
406 /*
407 * Common part for opening disk images and files
408 */
409 static int bdrv_open_common(BlockDriverState *bs, const char *filename,
410 int flags, BlockDriver *drv)
411 {
412 int ret, open_flags;
413
414 assert(drv != NULL);
415
416 bs->file = NULL;
417 bs->total_sectors = 0;
418 bs->encrypted = 0;
419 bs->valid_key = 0;
420 bs->open_flags = flags;
421 /* buffer_alignment defaulted to 512, drivers can change this value */
422 bs->buffer_alignment = 512;
423
424 pstrcpy(bs->filename, sizeof(bs->filename), filename);
425
426 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv)) {
427 return -ENOTSUP;
428 }
429
430 bs->drv = drv;
431 bs->opaque = qemu_mallocz(drv->instance_size);
432
433 /*
434 * Yes, BDRV_O_NOCACHE aka O_DIRECT means we have to present a
435 * write cache to the guest. We do need the fdatasync to flush
436 * out transactions for block allocations, and we maybe have a
437 * volatile write cache in our backing device to deal with.
438 */
439 if (flags & (BDRV_O_CACHE_WB|BDRV_O_NOCACHE))
440 bs->enable_write_cache = 1;
441
442 /*
443 * Clear flags that are internal to the block layer before opening the
444 * image.
445 */
446 open_flags = flags & ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
447
448 /*
449 * Snapshots should be writeable.
450 */
451 if (bs->is_temporary) {
452 open_flags |= BDRV_O_RDWR;
453 }
454
455 /* Open the image, either directly or using a protocol */
456 if (drv->bdrv_file_open) {
457 ret = drv->bdrv_file_open(bs, filename, open_flags);
458 } else {
459 ret = bdrv_file_open(&bs->file, filename, open_flags);
460 if (ret >= 0) {
461 ret = drv->bdrv_open(bs, open_flags);
462 }
463 }
464
465 if (ret < 0) {
466 goto free_and_fail;
467 }
468
469 bs->keep_read_only = bs->read_only = !(open_flags & BDRV_O_RDWR);
470
471 ret = refresh_total_sectors(bs, bs->total_sectors);
472 if (ret < 0) {
473 goto free_and_fail;
474 }
475
476 #ifndef _WIN32
477 if (bs->is_temporary) {
478 unlink(filename);
479 }
480 #endif
481 return 0;
482
483 free_and_fail:
484 if (bs->file) {
485 bdrv_delete(bs->file);
486 bs->file = NULL;
487 }
488 qemu_free(bs->opaque);
489 bs->opaque = NULL;
490 bs->drv = NULL;
491 return ret;
492 }
493
494 /*
495 * Opens a file using a protocol (file, host_device, nbd, ...)
496 */
497 int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags)
498 {
499 BlockDriverState *bs;
500 BlockDriver *drv;
501 int ret;
502
503 drv = bdrv_find_protocol(filename);
504 if (!drv) {
505 return -ENOENT;
506 }
507
508 bs = bdrv_new("");
509 ret = bdrv_open_common(bs, filename, flags, drv);
510 if (ret < 0) {
511 bdrv_delete(bs);
512 return ret;
513 }
514 bs->growable = 1;
515 *pbs = bs;
516 return 0;
517 }
518
519 /*
520 * Opens a disk image (raw, qcow2, vmdk, ...)
521 */
522 int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
523 BlockDriver *drv)
524 {
525 int ret;
526 int probed = 0;
527
528 if (flags & BDRV_O_SNAPSHOT) {
529 BlockDriverState *bs1;
530 int64_t total_size;
531 int is_protocol = 0;
532 BlockDriver *bdrv_qcow2;
533 QEMUOptionParameter *options;
534 char tmp_filename[PATH_MAX];
535 char backing_filename[PATH_MAX];
536
537 /* if snapshot, we create a temporary backing file and open it
538 instead of opening 'filename' directly */
539
540 /* if there is a backing file, use it */
541 bs1 = bdrv_new("");
542 ret = bdrv_open(bs1, filename, 0, drv);
543 if (ret < 0) {
544 bdrv_delete(bs1);
545 return ret;
546 }
547 total_size = bdrv_getlength(bs1) & BDRV_SECTOR_MASK;
548
549 if (bs1->drv && bs1->drv->protocol_name)
550 is_protocol = 1;
551
552 bdrv_delete(bs1);
553
554 get_tmp_filename(tmp_filename, sizeof(tmp_filename));
555
556 /* Real path is meaningless for protocols */
557 if (is_protocol)
558 snprintf(backing_filename, sizeof(backing_filename),
559 "%s", filename);
560 else if (!realpath(filename, backing_filename))
561 return -errno;
562
563 bdrv_qcow2 = bdrv_find_format("qcow2");
564 options = parse_option_parameters("", bdrv_qcow2->create_options, NULL);
565
566 set_option_parameter_int(options, BLOCK_OPT_SIZE, total_size);
567 set_option_parameter(options, BLOCK_OPT_BACKING_FILE, backing_filename);
568 if (drv) {
569 set_option_parameter(options, BLOCK_OPT_BACKING_FMT,
570 drv->format_name);
571 }
572
573 ret = bdrv_create(bdrv_qcow2, tmp_filename, options);
574 free_option_parameters(options);
575 if (ret < 0) {
576 return ret;
577 }
578
579 filename = tmp_filename;
580 drv = bdrv_qcow2;
581 bs->is_temporary = 1;
582 }
583
584 /* Find the right image format driver */
585 if (!drv) {
586 ret = find_image_format(filename, &drv);
587 probed = 1;
588 }
589
590 if (!drv) {
591 goto unlink_and_fail;
592 }
593
594 /* Open the image */
595 ret = bdrv_open_common(bs, filename, flags, drv);
596 if (ret < 0) {
597 goto unlink_and_fail;
598 }
599
600 bs->probed = probed;
601
602 /* If there is a backing file, use it */
603 if ((flags & BDRV_O_NO_BACKING) == 0 && bs->backing_file[0] != '\0') {
604 char backing_filename[PATH_MAX];
605 int back_flags;
606 BlockDriver *back_drv = NULL;
607
608 bs->backing_hd = bdrv_new("");
609 path_combine(backing_filename, sizeof(backing_filename),
610 filename, bs->backing_file);
611 if (bs->backing_format[0] != '\0')
612 back_drv = bdrv_find_format(bs->backing_format);
613
614 /* backing files always opened read-only */
615 back_flags =
616 flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
617
618 ret = bdrv_open(bs->backing_hd, backing_filename, back_flags, back_drv);
619 if (ret < 0) {
620 bdrv_close(bs);
621 return ret;
622 }
623 if (bs->is_temporary) {
624 bs->backing_hd->keep_read_only = !(flags & BDRV_O_RDWR);
625 } else {
626 /* base image inherits from "parent" */
627 bs->backing_hd->keep_read_only = bs->keep_read_only;
628 }
629 }
630
631 if (!bdrv_key_required(bs)) {
632 /* call the change callback */
633 bs->media_changed = 1;
634 if (bs->change_cb)
635 bs->change_cb(bs->change_opaque);
636 }
637
638 return 0;
639
640 unlink_and_fail:
641 if (bs->is_temporary) {
642 unlink(filename);
643 }
644 return ret;
645 }
646
647 void bdrv_close(BlockDriverState *bs)
648 {
649 if (bs->drv) {
650 if (bs == bs_snapshots) {
651 bs_snapshots = NULL;
652 }
653 if (bs->backing_hd) {
654 bdrv_delete(bs->backing_hd);
655 bs->backing_hd = NULL;
656 }
657 bs->drv->bdrv_close(bs);
658 qemu_free(bs->opaque);
659 #ifdef _WIN32
660 if (bs->is_temporary) {
661 unlink(bs->filename);
662 }
663 #endif
664 bs->opaque = NULL;
665 bs->drv = NULL;
666
667 if (bs->file != NULL) {
668 bdrv_close(bs->file);
669 }
670
671 /* call the change callback */
672 bs->media_changed = 1;
673 if (bs->change_cb)
674 bs->change_cb(bs->change_opaque);
675 }
676 }
677
678 void bdrv_close_all(void)
679 {
680 BlockDriverState *bs;
681
682 QTAILQ_FOREACH(bs, &bdrv_states, list) {
683 bdrv_close(bs);
684 }
685 }
686
687 void bdrv_delete(BlockDriverState *bs)
688 {
689 assert(!bs->peer);
690
691 /* remove from list, if necessary */
692 if (bs->device_name[0] != '\0') {
693 QTAILQ_REMOVE(&bdrv_states, bs, list);
694 }
695
696 bdrv_close(bs);
697 if (bs->file != NULL) {
698 bdrv_delete(bs->file);
699 }
700
701 assert(bs != bs_snapshots);
702 qemu_free(bs);
703 }
704
705 int bdrv_attach(BlockDriverState *bs, DeviceState *qdev)
706 {
707 if (bs->peer) {
708 return -EBUSY;
709 }
710 bs->peer = qdev;
711 return 0;
712 }
713
714 void bdrv_detach(BlockDriverState *bs, DeviceState *qdev)
715 {
716 assert(bs->peer == qdev);
717 bs->peer = NULL;
718 }
719
720 DeviceState *bdrv_get_attached(BlockDriverState *bs)
721 {
722 return bs->peer;
723 }
724
725 /*
726 * Run consistency checks on an image
727 *
728 * Returns 0 if the check could be completed (it doesn't mean that the image is
729 * free of errors) or -errno when an internal error occured. The results of the
730 * check are stored in res.
731 */
732 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res)
733 {
734 if (bs->drv->bdrv_check == NULL) {
735 return -ENOTSUP;
736 }
737
738 memset(res, 0, sizeof(*res));
739 return bs->drv->bdrv_check(bs, res);
740 }
741
742 #define COMMIT_BUF_SECTORS 2048
743
744 /* commit COW file into the raw image */
745 int bdrv_commit(BlockDriverState *bs)
746 {
747 BlockDriver *drv = bs->drv;
748 BlockDriver *backing_drv;
749 int64_t sector, total_sectors;
750 int n, ro, open_flags;
751 int ret = 0, rw_ret = 0;
752 uint8_t *buf;
753 char filename[1024];
754 BlockDriverState *bs_rw, *bs_ro;
755
756 if (!drv)
757 return -ENOMEDIUM;
758
759 if (!bs->backing_hd) {
760 return -ENOTSUP;
761 }
762
763 if (bs->backing_hd->keep_read_only) {
764 return -EACCES;
765 }
766
767 backing_drv = bs->backing_hd->drv;
768 ro = bs->backing_hd->read_only;
769 strncpy(filename, bs->backing_hd->filename, sizeof(filename));
770 open_flags = bs->backing_hd->open_flags;
771
772 if (ro) {
773 /* re-open as RW */
774 bdrv_delete(bs->backing_hd);
775 bs->backing_hd = NULL;
776 bs_rw = bdrv_new("");
777 rw_ret = bdrv_open(bs_rw, filename, open_flags | BDRV_O_RDWR,
778 backing_drv);
779 if (rw_ret < 0) {
780 bdrv_delete(bs_rw);
781 /* try to re-open read-only */
782 bs_ro = bdrv_new("");
783 ret = bdrv_open(bs_ro, filename, open_flags & ~BDRV_O_RDWR,
784 backing_drv);
785 if (ret < 0) {
786 bdrv_delete(bs_ro);
787 /* drive not functional anymore */
788 bs->drv = NULL;
789 return ret;
790 }
791 bs->backing_hd = bs_ro;
792 return rw_ret;
793 }
794 bs->backing_hd = bs_rw;
795 }
796
797 total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
798 buf = qemu_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE);
799
800 for (sector = 0; sector < total_sectors; sector += n) {
801 if (drv->bdrv_is_allocated(bs, sector, COMMIT_BUF_SECTORS, &n)) {
802
803 if (bdrv_read(bs, sector, buf, n) != 0) {
804 ret = -EIO;
805 goto ro_cleanup;
806 }
807
808 if (bdrv_write(bs->backing_hd, sector, buf, n) != 0) {
809 ret = -EIO;
810 goto ro_cleanup;
811 }
812 }
813 }
814
815 if (drv->bdrv_make_empty) {
816 ret = drv->bdrv_make_empty(bs);
817 bdrv_flush(bs);
818 }
819
820 /*
821 * Make sure all data we wrote to the backing device is actually
822 * stable on disk.
823 */
824 if (bs->backing_hd)
825 bdrv_flush(bs->backing_hd);
826
827 ro_cleanup:
828 qemu_free(buf);
829
830 if (ro) {
831 /* re-open as RO */
832 bdrv_delete(bs->backing_hd);
833 bs->backing_hd = NULL;
834 bs_ro = bdrv_new("");
835 ret = bdrv_open(bs_ro, filename, open_flags & ~BDRV_O_RDWR,
836 backing_drv);
837 if (ret < 0) {
838 bdrv_delete(bs_ro);
839 /* drive not functional anymore */
840 bs->drv = NULL;
841 return ret;
842 }
843 bs->backing_hd = bs_ro;
844 bs->backing_hd->keep_read_only = 0;
845 }
846
847 return ret;
848 }
849
850 void bdrv_commit_all(void)
851 {
852 BlockDriverState *bs;
853
854 QTAILQ_FOREACH(bs, &bdrv_states, list) {
855 bdrv_commit(bs);
856 }
857 }
858
859 /*
860 * Return values:
861 * 0 - success
862 * -EINVAL - backing format specified, but no file
863 * -ENOSPC - can't update the backing file because no space is left in the
864 * image file header
865 * -ENOTSUP - format driver doesn't support changing the backing file
866 */
867 int bdrv_change_backing_file(BlockDriverState *bs,
868 const char *backing_file, const char *backing_fmt)
869 {
870 BlockDriver *drv = bs->drv;
871
872 if (drv->bdrv_change_backing_file != NULL) {
873 return drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
874 } else {
875 return -ENOTSUP;
876 }
877 }
878
879 static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset,
880 size_t size)
881 {
882 int64_t len;
883
884 if (!bdrv_is_inserted(bs))
885 return -ENOMEDIUM;
886
887 if (bs->growable)
888 return 0;
889
890 len = bdrv_getlength(bs);
891
892 if (offset < 0)
893 return -EIO;
894
895 if ((offset > len) || (len - offset < size))
896 return -EIO;
897
898 return 0;
899 }
900
901 static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num,
902 int nb_sectors)
903 {
904 return bdrv_check_byte_request(bs, sector_num * BDRV_SECTOR_SIZE,
905 nb_sectors * BDRV_SECTOR_SIZE);
906 }
907
908 /* return < 0 if error. See bdrv_write() for the return codes */
909 int bdrv_read(BlockDriverState *bs, int64_t sector_num,
910 uint8_t *buf, int nb_sectors)
911 {
912 BlockDriver *drv = bs->drv;
913
914 if (!drv)
915 return -ENOMEDIUM;
916 if (bdrv_check_request(bs, sector_num, nb_sectors))
917 return -EIO;
918
919 return drv->bdrv_read(bs, sector_num, buf, nb_sectors);
920 }
921
922 static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num,
923 int nb_sectors, int dirty)
924 {
925 int64_t start, end;
926 unsigned long val, idx, bit;
927
928 start = sector_num / BDRV_SECTORS_PER_DIRTY_CHUNK;
929 end = (sector_num + nb_sectors - 1) / BDRV_SECTORS_PER_DIRTY_CHUNK;
930
931 for (; start <= end; start++) {
932 idx = start / (sizeof(unsigned long) * 8);
933 bit = start % (sizeof(unsigned long) * 8);
934 val = bs->dirty_bitmap[idx];
935 if (dirty) {
936 if (!(val & (1 << bit))) {
937 bs->dirty_count++;
938 val |= 1 << bit;
939 }
940 } else {
941 if (val & (1 << bit)) {
942 bs->dirty_count--;
943 val &= ~(1 << bit);
944 }
945 }
946 bs->dirty_bitmap[idx] = val;
947 }
948 }
949
950 /* Return < 0 if error. Important errors are:
951 -EIO generic I/O error (may happen for all errors)
952 -ENOMEDIUM No media inserted.
953 -EINVAL Invalid sector number or nb_sectors
954 -EACCES Trying to write a read-only device
955 */
956 int bdrv_write(BlockDriverState *bs, int64_t sector_num,
957 const uint8_t *buf, int nb_sectors)
958 {
959 BlockDriver *drv = bs->drv;
960 if (!bs->drv)
961 return -ENOMEDIUM;
962 if (bs->read_only)
963 return -EACCES;
964 if (bdrv_check_request(bs, sector_num, nb_sectors))
965 return -EIO;
966
967 if (bs->dirty_bitmap) {
968 set_dirty_bitmap(bs, sector_num, nb_sectors, 1);
969 }
970
971 if (bs->wr_highest_sector < sector_num + nb_sectors - 1) {
972 bs->wr_highest_sector = sector_num + nb_sectors - 1;
973 }
974
975 return drv->bdrv_write(bs, sector_num, buf, nb_sectors);
976 }
977
978 int bdrv_pread(BlockDriverState *bs, int64_t offset,
979 void *buf, int count1)
980 {
981 uint8_t tmp_buf[BDRV_SECTOR_SIZE];
982 int len, nb_sectors, count;
983 int64_t sector_num;
984 int ret;
985
986 count = count1;
987 /* first read to align to sector start */
988 len = (BDRV_SECTOR_SIZE - offset) & (BDRV_SECTOR_SIZE - 1);
989 if (len > count)
990 len = count;
991 sector_num = offset >> BDRV_SECTOR_BITS;
992 if (len > 0) {
993 if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0)
994 return ret;
995 memcpy(buf, tmp_buf + (offset & (BDRV_SECTOR_SIZE - 1)), len);
996 count -= len;
997 if (count == 0)
998 return count1;
999 sector_num++;
1000 buf += len;
1001 }
1002
1003 /* read the sectors "in place" */
1004 nb_sectors = count >> BDRV_SECTOR_BITS;
1005 if (nb_sectors > 0) {
1006 if ((ret = bdrv_read(bs, sector_num, buf, nb_sectors)) < 0)
1007 return ret;
1008 sector_num += nb_sectors;
1009 len = nb_sectors << BDRV_SECTOR_BITS;
1010 buf += len;
1011 count -= len;
1012 }
1013
1014 /* add data from the last sector */
1015 if (count > 0) {
1016 if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0)
1017 return ret;
1018 memcpy(buf, tmp_buf, count);
1019 }
1020 return count1;
1021 }
1022
1023 int bdrv_pwrite(BlockDriverState *bs, int64_t offset,
1024 const void *buf, int count1)
1025 {
1026 uint8_t tmp_buf[BDRV_SECTOR_SIZE];
1027 int len, nb_sectors, count;
1028 int64_t sector_num;
1029 int ret;
1030
1031 count = count1;
1032 /* first write to align to sector start */
1033 len = (BDRV_SECTOR_SIZE - offset) & (BDRV_SECTOR_SIZE - 1);
1034 if (len > count)
1035 len = count;
1036 sector_num = offset >> BDRV_SECTOR_BITS;
1037 if (len > 0) {
1038 if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0)
1039 return ret;
1040 memcpy(tmp_buf + (offset & (BDRV_SECTOR_SIZE - 1)), buf, len);
1041 if ((ret = bdrv_write(bs, sector_num, tmp_buf, 1)) < 0)
1042 return ret;
1043 count -= len;
1044 if (count == 0)
1045 return count1;
1046 sector_num++;
1047 buf += len;
1048 }
1049
1050 /* write the sectors "in place" */
1051 nb_sectors = count >> BDRV_SECTOR_BITS;
1052 if (nb_sectors > 0) {
1053 if ((ret = bdrv_write(bs, sector_num, buf, nb_sectors)) < 0)
1054 return ret;
1055 sector_num += nb_sectors;
1056 len = nb_sectors << BDRV_SECTOR_BITS;
1057 buf += len;
1058 count -= len;
1059 }
1060
1061 /* add data from the last sector */
1062 if (count > 0) {
1063 if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0)
1064 return ret;
1065 memcpy(tmp_buf, buf, count);
1066 if ((ret = bdrv_write(bs, sector_num, tmp_buf, 1)) < 0)
1067 return ret;
1068 }
1069 return count1;
1070 }
1071
1072 /*
1073 * Writes to the file and ensures that no writes are reordered across this
1074 * request (acts as a barrier)
1075 *
1076 * Returns 0 on success, -errno in error cases.
1077 */
1078 int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset,
1079 const void *buf, int count)
1080 {
1081 int ret;
1082
1083 ret = bdrv_pwrite(bs, offset, buf, count);
1084 if (ret < 0) {
1085 return ret;
1086 }
1087
1088 /* No flush needed for cache=writethrough, it uses O_DSYNC */
1089 if ((bs->open_flags & BDRV_O_CACHE_MASK) != 0) {
1090 bdrv_flush(bs);
1091 }
1092
1093 return 0;
1094 }
1095
1096 /*
1097 * Writes to the file and ensures that no writes are reordered across this
1098 * request (acts as a barrier)
1099 *
1100 * Returns 0 on success, -errno in error cases.
1101 */
1102 int bdrv_write_sync(BlockDriverState *bs, int64_t sector_num,
1103 const uint8_t *buf, int nb_sectors)
1104 {
1105 return bdrv_pwrite_sync(bs, BDRV_SECTOR_SIZE * sector_num,
1106 buf, BDRV_SECTOR_SIZE * nb_sectors);
1107 }
1108
1109 /**
1110 * Truncate file to 'offset' bytes (needed only for file protocols)
1111 */
1112 int bdrv_truncate(BlockDriverState *bs, int64_t offset)
1113 {
1114 BlockDriver *drv = bs->drv;
1115 int ret;
1116 if (!drv)
1117 return -ENOMEDIUM;
1118 if (!drv->bdrv_truncate)
1119 return -ENOTSUP;
1120 if (bs->read_only)
1121 return -EACCES;
1122 ret = drv->bdrv_truncate(bs, offset);
1123 if (ret == 0) {
1124 ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
1125 }
1126 return ret;
1127 }
1128
1129 /**
1130 * Length of a file in bytes. Return < 0 if error or unknown.
1131 */
1132 int64_t bdrv_getlength(BlockDriverState *bs)
1133 {
1134 BlockDriver *drv = bs->drv;
1135 if (!drv)
1136 return -ENOMEDIUM;
1137
1138 /* Fixed size devices use the total_sectors value for speed instead of
1139 issuing a length query (like lseek) on each call. Also, legacy block
1140 drivers don't provide a bdrv_getlength function and must use
1141 total_sectors. */
1142 if (!bs->growable || !drv->bdrv_getlength) {
1143 return bs->total_sectors * BDRV_SECTOR_SIZE;
1144 }
1145 return drv->bdrv_getlength(bs);
1146 }
1147
1148 /* return 0 as number of sectors if no device present or error */
1149 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
1150 {
1151 int64_t length;
1152 length = bdrv_getlength(bs);
1153 if (length < 0)
1154 length = 0;
1155 else
1156 length = length >> BDRV_SECTOR_BITS;
1157 *nb_sectors_ptr = length;
1158 }
1159
1160 struct partition {
1161 uint8_t boot_ind; /* 0x80 - active */
1162 uint8_t head; /* starting head */
1163 uint8_t sector; /* starting sector */
1164 uint8_t cyl; /* starting cylinder */
1165 uint8_t sys_ind; /* What partition type */
1166 uint8_t end_head; /* end head */
1167 uint8_t end_sector; /* end sector */
1168 uint8_t end_cyl; /* end cylinder */
1169 uint32_t start_sect; /* starting sector counting from 0 */
1170 uint32_t nr_sects; /* nr of sectors in partition */
1171 } __attribute__((packed));
1172
1173 /* try to guess the disk logical geometry from the MSDOS partition table. Return 0 if OK, -1 if could not guess */
1174 static int guess_disk_lchs(BlockDriverState *bs,
1175 int *pcylinders, int *pheads, int *psectors)
1176 {
1177 uint8_t buf[BDRV_SECTOR_SIZE];
1178 int ret, i, heads, sectors, cylinders;
1179 struct partition *p;
1180 uint32_t nr_sects;
1181 uint64_t nb_sectors;
1182
1183 bdrv_get_geometry(bs, &nb_sectors);
1184
1185 ret = bdrv_read(bs, 0, buf, 1);
1186 if (ret < 0)
1187 return -1;
1188 /* test msdos magic */
1189 if (buf[510] != 0x55 || buf[511] != 0xaa)
1190 return -1;
1191 for(i = 0; i < 4; i++) {
1192 p = ((struct partition *)(buf + 0x1be)) + i;
1193 nr_sects = le32_to_cpu(p->nr_sects);
1194 if (nr_sects && p->end_head) {
1195 /* We make the assumption that the partition terminates on
1196 a cylinder boundary */
1197 heads = p->end_head + 1;
1198 sectors = p->end_sector & 63;
1199 if (sectors == 0)
1200 continue;
1201 cylinders = nb_sectors / (heads * sectors);
1202 if (cylinders < 1 || cylinders > 16383)
1203 continue;
1204 *pheads = heads;
1205 *psectors = sectors;
1206 *pcylinders = cylinders;
1207 #if 0
1208 printf("guessed geometry: LCHS=%d %d %d\n",
1209 cylinders, heads, sectors);
1210 #endif
1211 return 0;
1212 }
1213 }
1214 return -1;
1215 }
1216
1217 void bdrv_guess_geometry(BlockDriverState *bs, int *pcyls, int *pheads, int *psecs)
1218 {
1219 int translation, lba_detected = 0;
1220 int cylinders, heads, secs;
1221 uint64_t nb_sectors;
1222
1223 /* if a geometry hint is available, use it */
1224 bdrv_get_geometry(bs, &nb_sectors);
1225 bdrv_get_geometry_hint(bs, &cylinders, &heads, &secs);
1226 translation = bdrv_get_translation_hint(bs);
1227 if (cylinders != 0) {
1228 *pcyls = cylinders;
1229 *pheads = heads;
1230 *psecs = secs;
1231 } else {
1232 if (guess_disk_lchs(bs, &cylinders, &heads, &secs) == 0) {
1233 if (heads > 16) {
1234 /* if heads > 16, it means that a BIOS LBA
1235 translation was active, so the default
1236 hardware geometry is OK */
1237 lba_detected = 1;
1238 goto default_geometry;
1239 } else {
1240 *pcyls = cylinders;
1241 *pheads = heads;
1242 *psecs = secs;
1243 /* disable any translation to be in sync with
1244 the logical geometry */
1245 if (translation == BIOS_ATA_TRANSLATION_AUTO) {
1246 bdrv_set_translation_hint(bs,
1247 BIOS_ATA_TRANSLATION_NONE);
1248 }
1249 }
1250 } else {
1251 default_geometry:
1252 /* if no geometry, use a standard physical disk geometry */
1253 cylinders = nb_sectors / (16 * 63);
1254
1255 if (cylinders > 16383)
1256 cylinders = 16383;
1257 else if (cylinders < 2)
1258 cylinders = 2;
1259 *pcyls = cylinders;
1260 *pheads = 16;
1261 *psecs = 63;
1262 if ((lba_detected == 1) && (translation == BIOS_ATA_TRANSLATION_AUTO)) {
1263 if ((*pcyls * *pheads) <= 131072) {
1264 bdrv_set_translation_hint(bs,
1265 BIOS_ATA_TRANSLATION_LARGE);
1266 } else {
1267 bdrv_set_translation_hint(bs,
1268 BIOS_ATA_TRANSLATION_LBA);
1269 }
1270 }
1271 }
1272 bdrv_set_geometry_hint(bs, *pcyls, *pheads, *psecs);
1273 }
1274 }
1275
1276 void bdrv_set_geometry_hint(BlockDriverState *bs,
1277 int cyls, int heads, int secs)
1278 {
1279 bs->cyls = cyls;
1280 bs->heads = heads;
1281 bs->secs = secs;
1282 }
1283
1284 void bdrv_set_type_hint(BlockDriverState *bs, int type)
1285 {
1286 bs->type = type;
1287 bs->removable = ((type == BDRV_TYPE_CDROM ||
1288 type == BDRV_TYPE_FLOPPY));
1289 }
1290
1291 void bdrv_set_translation_hint(BlockDriverState *bs, int translation)
1292 {
1293 bs->translation = translation;
1294 }
1295
1296 void bdrv_get_geometry_hint(BlockDriverState *bs,
1297 int *pcyls, int *pheads, int *psecs)
1298 {
1299 *pcyls = bs->cyls;
1300 *pheads = bs->heads;
1301 *psecs = bs->secs;
1302 }
1303
1304 int bdrv_get_type_hint(BlockDriverState *bs)
1305 {
1306 return bs->type;
1307 }
1308
1309 int bdrv_get_translation_hint(BlockDriverState *bs)
1310 {
1311 return bs->translation;
1312 }
1313
1314 void bdrv_set_on_error(BlockDriverState *bs, BlockErrorAction on_read_error,
1315 BlockErrorAction on_write_error)
1316 {
1317 bs->on_read_error = on_read_error;
1318 bs->on_write_error = on_write_error;
1319 }
1320
1321 BlockErrorAction bdrv_get_on_error(BlockDriverState *bs, int is_read)
1322 {
1323 return is_read ? bs->on_read_error : bs->on_write_error;
1324 }
1325
1326 void bdrv_set_removable(BlockDriverState *bs, int removable)
1327 {
1328 bs->removable = removable;
1329 if (removable && bs == bs_snapshots) {
1330 bs_snapshots = NULL;
1331 }
1332 }
1333
1334 int bdrv_is_removable(BlockDriverState *bs)
1335 {
1336 return bs->removable;
1337 }
1338
1339 int bdrv_is_read_only(BlockDriverState *bs)
1340 {
1341 return bs->read_only;
1342 }
1343
1344 int bdrv_is_sg(BlockDriverState *bs)
1345 {
1346 return bs->sg;
1347 }
1348
1349 int bdrv_enable_write_cache(BlockDriverState *bs)
1350 {
1351 return bs->enable_write_cache;
1352 }
1353
1354 /* XXX: no longer used */
1355 void bdrv_set_change_cb(BlockDriverState *bs,
1356 void (*change_cb)(void *opaque), void *opaque)
1357 {
1358 bs->change_cb = change_cb;
1359 bs->change_opaque = opaque;
1360 }
1361
1362 int bdrv_is_encrypted(BlockDriverState *bs)
1363 {
1364 if (bs->backing_hd && bs->backing_hd->encrypted)
1365 return 1;
1366 return bs->encrypted;
1367 }
1368
1369 int bdrv_key_required(BlockDriverState *bs)
1370 {
1371 BlockDriverState *backing_hd = bs->backing_hd;
1372
1373 if (backing_hd && backing_hd->encrypted && !backing_hd->valid_key)
1374 return 1;
1375 return (bs->encrypted && !bs->valid_key);
1376 }
1377
1378 int bdrv_set_key(BlockDriverState *bs, const char *key)
1379 {
1380 int ret;
1381 if (bs->backing_hd && bs->backing_hd->encrypted) {
1382 ret = bdrv_set_key(bs->backing_hd, key);
1383 if (ret < 0)
1384 return ret;
1385 if (!bs->encrypted)
1386 return 0;
1387 }
1388 if (!bs->encrypted) {
1389 return -EINVAL;
1390 } else if (!bs->drv || !bs->drv->bdrv_set_key) {
1391 return -ENOMEDIUM;
1392 }
1393 ret = bs->drv->bdrv_set_key(bs, key);
1394 if (ret < 0) {
1395 bs->valid_key = 0;
1396 } else if (!bs->valid_key) {
1397 bs->valid_key = 1;
1398 /* call the change callback now, we skipped it on open */
1399 bs->media_changed = 1;
1400 if (bs->change_cb)
1401 bs->change_cb(bs->change_opaque);
1402 }
1403 return ret;
1404 }
1405
1406 void bdrv_get_format(BlockDriverState *bs, char *buf, int buf_size)
1407 {
1408 if (!bs->drv) {
1409 buf[0] = '\0';
1410 } else {
1411 pstrcpy(buf, buf_size, bs->drv->format_name);
1412 }
1413 }
1414
1415 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
1416 void *opaque)
1417 {
1418 BlockDriver *drv;
1419
1420 QLIST_FOREACH(drv, &bdrv_drivers, list) {
1421 it(opaque, drv->format_name);
1422 }
1423 }
1424
1425 BlockDriverState *bdrv_find(const char *name)
1426 {
1427 BlockDriverState *bs;
1428
1429 QTAILQ_FOREACH(bs, &bdrv_states, list) {
1430 if (!strcmp(name, bs->device_name)) {
1431 return bs;
1432 }
1433 }
1434 return NULL;
1435 }
1436
1437 BlockDriverState *bdrv_next(BlockDriverState *bs)
1438 {
1439 if (!bs) {
1440 return QTAILQ_FIRST(&bdrv_states);
1441 }
1442 return QTAILQ_NEXT(bs, list);
1443 }
1444
1445 void bdrv_iterate(void (*it)(void *opaque, BlockDriverState *bs), void *opaque)
1446 {
1447 BlockDriverState *bs;
1448
1449 QTAILQ_FOREACH(bs, &bdrv_states, list) {
1450 it(opaque, bs);
1451 }
1452 }
1453
1454 const char *bdrv_get_device_name(BlockDriverState *bs)
1455 {
1456 return bs->device_name;
1457 }
1458
1459 void bdrv_flush(BlockDriverState *bs)
1460 {
1461 if (bs->open_flags & BDRV_O_NO_FLUSH) {
1462 return;
1463 }
1464
1465 if (bs->drv && bs->drv->bdrv_flush)
1466 bs->drv->bdrv_flush(bs);
1467 }
1468
1469 void bdrv_flush_all(void)
1470 {
1471 BlockDriverState *bs;
1472
1473 QTAILQ_FOREACH(bs, &bdrv_states, list) {
1474 if (bs->drv && !bdrv_is_read_only(bs) &&
1475 (!bdrv_is_removable(bs) || bdrv_is_inserted(bs))) {
1476 bdrv_flush(bs);
1477 }
1478 }
1479 }
1480
1481 int bdrv_has_zero_init(BlockDriverState *bs)
1482 {
1483 assert(bs->drv);
1484
1485 if (bs->drv->bdrv_has_zero_init) {
1486 return bs->drv->bdrv_has_zero_init(bs);
1487 }
1488
1489 return 1;
1490 }
1491
1492 /*
1493 * Returns true iff the specified sector is present in the disk image. Drivers
1494 * not implementing the functionality are assumed to not support backing files,
1495 * hence all their sectors are reported as allocated.
1496 *
1497 * 'pnum' is set to the number of sectors (including and immediately following
1498 * the specified sector) that are known to be in the same
1499 * allocated/unallocated state.
1500 *
1501 * 'nb_sectors' is the max value 'pnum' should be set to.
1502 */
1503 int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
1504 int *pnum)
1505 {
1506 int64_t n;
1507 if (!bs->drv->bdrv_is_allocated) {
1508 if (sector_num >= bs->total_sectors) {
1509 *pnum = 0;
1510 return 0;
1511 }
1512 n = bs->total_sectors - sector_num;
1513 *pnum = (n < nb_sectors) ? (n) : (nb_sectors);
1514 return 1;
1515 }
1516 return bs->drv->bdrv_is_allocated(bs, sector_num, nb_sectors, pnum);
1517 }
1518
1519 void bdrv_mon_event(const BlockDriverState *bdrv,
1520 BlockMonEventAction action, int is_read)
1521 {
1522 QObject *data;
1523 const char *action_str;
1524
1525 switch (action) {
1526 case BDRV_ACTION_REPORT:
1527 action_str = "report";
1528 break;
1529 case BDRV_ACTION_IGNORE:
1530 action_str = "ignore";
1531 break;
1532 case BDRV_ACTION_STOP:
1533 action_str = "stop";
1534 break;
1535 default:
1536 abort();
1537 }
1538
1539 data = qobject_from_jsonf("{ 'device': %s, 'action': %s, 'operation': %s }",
1540 bdrv->device_name,
1541 action_str,
1542 is_read ? "read" : "write");
1543 monitor_protocol_event(QEVENT_BLOCK_IO_ERROR, data);
1544
1545 qobject_decref(data);
1546 }
1547
1548 static void bdrv_print_dict(QObject *obj, void *opaque)
1549 {
1550 QDict *bs_dict;
1551 Monitor *mon = opaque;
1552
1553 bs_dict = qobject_to_qdict(obj);
1554
1555 monitor_printf(mon, "%s: type=%s removable=%d",
1556 qdict_get_str(bs_dict, "device"),
1557 qdict_get_str(bs_dict, "type"),
1558 qdict_get_bool(bs_dict, "removable"));
1559
1560 if (qdict_get_bool(bs_dict, "removable")) {
1561 monitor_printf(mon, " locked=%d", qdict_get_bool(bs_dict, "locked"));
1562 }
1563
1564 if (qdict_haskey(bs_dict, "inserted")) {
1565 QDict *qdict = qobject_to_qdict(qdict_get(bs_dict, "inserted"));
1566
1567 monitor_printf(mon, " file=");
1568 monitor_print_filename(mon, qdict_get_str(qdict, "file"));
1569 if (qdict_haskey(qdict, "backing_file")) {
1570 monitor_printf(mon, " backing_file=");
1571 monitor_print_filename(mon, qdict_get_str(qdict, "backing_file"));
1572 }
1573 monitor_printf(mon, " ro=%d drv=%s encrypted=%d",
1574 qdict_get_bool(qdict, "ro"),
1575 qdict_get_str(qdict, "drv"),
1576 qdict_get_bool(qdict, "encrypted"));
1577 } else {
1578 monitor_printf(mon, " [not inserted]");
1579 }
1580
1581 monitor_printf(mon, "\n");
1582 }
1583
1584 void bdrv_info_print(Monitor *mon, const QObject *data)
1585 {
1586 qlist_iter(qobject_to_qlist(data), bdrv_print_dict, mon);
1587 }
1588
1589 void bdrv_info(Monitor *mon, QObject **ret_data)
1590 {
1591 QList *bs_list;
1592 BlockDriverState *bs;
1593
1594 bs_list = qlist_new();
1595
1596 QTAILQ_FOREACH(bs, &bdrv_states, list) {
1597 QObject *bs_obj;
1598 const char *type = "unknown";
1599
1600 switch(bs->type) {
1601 case BDRV_TYPE_HD:
1602 type = "hd";
1603 break;
1604 case BDRV_TYPE_CDROM:
1605 type = "cdrom";
1606 break;
1607 case BDRV_TYPE_FLOPPY:
1608 type = "floppy";
1609 break;
1610 }
1611
1612 bs_obj = qobject_from_jsonf("{ 'device': %s, 'type': %s, "
1613 "'removable': %i, 'locked': %i }",
1614 bs->device_name, type, bs->removable,
1615 bs->locked);
1616
1617 if (bs->drv) {
1618 QObject *obj;
1619 QDict *bs_dict = qobject_to_qdict(bs_obj);
1620
1621 obj = qobject_from_jsonf("{ 'file': %s, 'ro': %i, 'drv': %s, "
1622 "'encrypted': %i }",
1623 bs->filename, bs->read_only,
1624 bs->drv->format_name,
1625 bdrv_is_encrypted(bs));
1626 if (bs->backing_file[0] != '\0') {
1627 QDict *qdict = qobject_to_qdict(obj);
1628 qdict_put(qdict, "backing_file",
1629 qstring_from_str(bs->backing_file));
1630 }
1631
1632 qdict_put_obj(bs_dict, "inserted", obj);
1633 }
1634 qlist_append_obj(bs_list, bs_obj);
1635 }
1636
1637 *ret_data = QOBJECT(bs_list);
1638 }
1639
1640 static void bdrv_stats_iter(QObject *data, void *opaque)
1641 {
1642 QDict *qdict;
1643 Monitor *mon = opaque;
1644
1645 qdict = qobject_to_qdict(data);
1646 monitor_printf(mon, "%s:", qdict_get_str(qdict, "device"));
1647
1648 qdict = qobject_to_qdict(qdict_get(qdict, "stats"));
1649 monitor_printf(mon, " rd_bytes=%" PRId64
1650 " wr_bytes=%" PRId64
1651 " rd_operations=%" PRId64
1652 " wr_operations=%" PRId64
1653 "\n",
1654 qdict_get_int(qdict, "rd_bytes"),
1655 qdict_get_int(qdict, "wr_bytes"),
1656 qdict_get_int(qdict, "rd_operations"),
1657 qdict_get_int(qdict, "wr_operations"));
1658 }
1659
1660 void bdrv_stats_print(Monitor *mon, const QObject *data)
1661 {
1662 qlist_iter(qobject_to_qlist(data), bdrv_stats_iter, mon);
1663 }
1664
1665 static QObject* bdrv_info_stats_bs(BlockDriverState *bs)
1666 {
1667 QObject *res;
1668 QDict *dict;
1669
1670 res = qobject_from_jsonf("{ 'stats': {"
1671 "'rd_bytes': %" PRId64 ","
1672 "'wr_bytes': %" PRId64 ","
1673 "'rd_operations': %" PRId64 ","
1674 "'wr_operations': %" PRId64 ","
1675 "'wr_highest_offset': %" PRId64
1676 "} }",
1677 bs->rd_bytes, bs->wr_bytes,
1678 bs->rd_ops, bs->wr_ops,
1679 bs->wr_highest_sector *
1680 (uint64_t)BDRV_SECTOR_SIZE);
1681 dict = qobject_to_qdict(res);
1682
1683 if (*bs->device_name) {
1684 qdict_put(dict, "device", qstring_from_str(bs->device_name));
1685 }
1686
1687 if (bs->file) {
1688 QObject *parent = bdrv_info_stats_bs(bs->file);
1689 qdict_put_obj(dict, "parent", parent);
1690 }
1691
1692 return res;
1693 }
1694
1695 void bdrv_info_stats(Monitor *mon, QObject **ret_data)
1696 {
1697 QObject *obj;
1698 QList *devices;
1699 BlockDriverState *bs;
1700
1701 devices = qlist_new();
1702
1703 QTAILQ_FOREACH(bs, &bdrv_states, list) {
1704 obj = bdrv_info_stats_bs(bs);
1705 qlist_append_obj(devices, obj);
1706 }
1707
1708 *ret_data = QOBJECT(devices);
1709 }
1710
1711 const char *bdrv_get_encrypted_filename(BlockDriverState *bs)
1712 {
1713 if (bs->backing_hd && bs->backing_hd->encrypted)
1714 return bs->backing_file;
1715 else if (bs->encrypted)
1716 return bs->filename;
1717 else
1718 return NULL;
1719 }
1720
1721 void bdrv_get_backing_filename(BlockDriverState *bs,
1722 char *filename, int filename_size)
1723 {
1724 if (!bs->backing_file) {
1725 pstrcpy(filename, filename_size, "");
1726 } else {
1727 pstrcpy(filename, filename_size, bs->backing_file);
1728 }
1729 }
1730
1731 int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num,
1732 const uint8_t *buf, int nb_sectors)
1733 {
1734 BlockDriver *drv = bs->drv;
1735 if (!drv)
1736 return -ENOMEDIUM;
1737 if (!drv->bdrv_write_compressed)
1738 return -ENOTSUP;
1739 if (bdrv_check_request(bs, sector_num, nb_sectors))
1740 return -EIO;
1741
1742 if (bs->dirty_bitmap) {
1743 set_dirty_bitmap(bs, sector_num, nb_sectors, 1);
1744 }
1745
1746 return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors);
1747 }
1748
1749 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1750 {
1751 BlockDriver *drv = bs->drv;
1752 if (!drv)
1753 return -ENOMEDIUM;
1754 if (!drv->bdrv_get_info)
1755 return -ENOTSUP;
1756 memset(bdi, 0, sizeof(*bdi));
1757 return drv->bdrv_get_info(bs, bdi);
1758 }
1759
1760 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
1761 int64_t pos, int size)
1762 {
1763 BlockDriver *drv = bs->drv;
1764 if (!drv)
1765 return -ENOMEDIUM;
1766 if (drv->bdrv_save_vmstate)
1767 return drv->bdrv_save_vmstate(bs, buf, pos, size);
1768 if (bs->file)
1769 return bdrv_save_vmstate(bs->file, buf, pos, size);
1770 return -ENOTSUP;
1771 }
1772
1773 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
1774 int64_t pos, int size)
1775 {
1776 BlockDriver *drv = bs->drv;
1777 if (!drv)
1778 return -ENOMEDIUM;
1779 if (drv->bdrv_load_vmstate)
1780 return drv->bdrv_load_vmstate(bs, buf, pos, size);
1781 if (bs->file)
1782 return bdrv_load_vmstate(bs->file, buf, pos, size);
1783 return -ENOTSUP;
1784 }
1785
1786 void bdrv_debug_event(BlockDriverState *bs, BlkDebugEvent event)
1787 {
1788 BlockDriver *drv = bs->drv;
1789
1790 if (!drv || !drv->bdrv_debug_event) {
1791 return;
1792 }
1793
1794 return drv->bdrv_debug_event(bs, event);
1795
1796 }
1797
1798 /**************************************************************/
1799 /* handling of snapshots */
1800
1801 int bdrv_can_snapshot(BlockDriverState *bs)
1802 {
1803 BlockDriver *drv = bs->drv;
1804 if (!drv || bdrv_is_removable(bs) || bdrv_is_read_only(bs)) {
1805 return 0;
1806 }
1807
1808 if (!drv->bdrv_snapshot_create) {
1809 if (bs->file != NULL) {
1810 return bdrv_can_snapshot(bs->file);
1811 }
1812 return 0;
1813 }
1814
1815 return 1;
1816 }
1817
1818 int bdrv_is_snapshot(BlockDriverState *bs)
1819 {
1820 return !!(bs->open_flags & BDRV_O_SNAPSHOT);
1821 }
1822
1823 BlockDriverState *bdrv_snapshots(void)
1824 {
1825 BlockDriverState *bs;
1826
1827 if (bs_snapshots) {
1828 return bs_snapshots;
1829 }
1830
1831 bs = NULL;
1832 while ((bs = bdrv_next(bs))) {
1833 if (bdrv_can_snapshot(bs)) {
1834 bs_snapshots = bs;
1835 return bs;
1836 }
1837 }
1838 return NULL;
1839 }
1840
1841 int bdrv_snapshot_create(BlockDriverState *bs,
1842 QEMUSnapshotInfo *sn_info)
1843 {
1844 BlockDriver *drv = bs->drv;
1845 if (!drv)
1846 return -ENOMEDIUM;
1847 if (drv->bdrv_snapshot_create)
1848 return drv->bdrv_snapshot_create(bs, sn_info);
1849 if (bs->file)
1850 return bdrv_snapshot_create(bs->file, sn_info);
1851 return -ENOTSUP;
1852 }
1853
1854 int bdrv_snapshot_goto(BlockDriverState *bs,
1855 const char *snapshot_id)
1856 {
1857 BlockDriver *drv = bs->drv;
1858 int ret, open_ret;
1859
1860 if (!drv)
1861 return -ENOMEDIUM;
1862 if (drv->bdrv_snapshot_goto)
1863 return drv->bdrv_snapshot_goto(bs, snapshot_id);
1864
1865 if (bs->file) {
1866 drv->bdrv_close(bs);
1867 ret = bdrv_snapshot_goto(bs->file, snapshot_id);
1868 open_ret = drv->bdrv_open(bs, bs->open_flags);
1869 if (open_ret < 0) {
1870 bdrv_delete(bs->file);
1871 bs->drv = NULL;
1872 return open_ret;
1873 }
1874 return ret;
1875 }
1876
1877 return -ENOTSUP;
1878 }
1879
1880 int bdrv_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
1881 {
1882 BlockDriver *drv = bs->drv;
1883 if (!drv)
1884 return -ENOMEDIUM;
1885 if (drv->bdrv_snapshot_delete)
1886 return drv->bdrv_snapshot_delete(bs, snapshot_id);
1887 if (bs->file)
1888 return bdrv_snapshot_delete(bs->file, snapshot_id);
1889 return -ENOTSUP;
1890 }
1891
1892 int bdrv_snapshot_list(BlockDriverState *bs,
1893 QEMUSnapshotInfo **psn_info)
1894 {
1895 BlockDriver *drv = bs->drv;
1896 if (!drv)
1897 return -ENOMEDIUM;
1898 if (drv->bdrv_snapshot_list)
1899 return drv->bdrv_snapshot_list(bs, psn_info);
1900 if (bs->file)
1901 return bdrv_snapshot_list(bs->file, psn_info);
1902 return -ENOTSUP;
1903 }
1904
1905 #define NB_SUFFIXES 4
1906
1907 char *get_human_readable_size(char *buf, int buf_size, int64_t size)
1908 {
1909 static const char suffixes[NB_SUFFIXES] = "KMGT";
1910 int64_t base;
1911 int i;
1912
1913 if (size <= 999) {
1914 snprintf(buf, buf_size, "%" PRId64, size);
1915 } else {
1916 base = 1024;
1917 for(i = 0; i < NB_SUFFIXES; i++) {
1918 if (size < (10 * base)) {
1919 snprintf(buf, buf_size, "%0.1f%c",
1920 (double)size / base,
1921 suffixes[i]);
1922 break;
1923 } else if (size < (1000 * base) || i == (NB_SUFFIXES - 1)) {
1924 snprintf(buf, buf_size, "%" PRId64 "%c",
1925 ((size + (base >> 1)) / base),
1926 suffixes[i]);
1927 break;
1928 }
1929 base = base * 1024;
1930 }
1931 }
1932 return buf;
1933 }
1934
1935 char *bdrv_snapshot_dump(char *buf, int buf_size, QEMUSnapshotInfo *sn)
1936 {
1937 char buf1[128], date_buf[128], clock_buf[128];
1938 #ifdef _WIN32
1939 struct tm *ptm;
1940 #else
1941 struct tm tm;
1942 #endif
1943 time_t ti;
1944 int64_t secs;
1945
1946 if (!sn) {
1947 snprintf(buf, buf_size,
1948 "%-10s%-20s%7s%20s%15s",
1949 "ID", "TAG", "VM SIZE", "DATE", "VM CLOCK");
1950 } else {
1951 ti = sn->date_sec;
1952 #ifdef _WIN32
1953 ptm = localtime(&ti);
1954 strftime(date_buf, sizeof(date_buf),
1955 "%Y-%m-%d %H:%M:%S", ptm);
1956 #else
1957 localtime_r(&ti, &tm);
1958 strftime(date_buf, sizeof(date_buf),
1959 "%Y-%m-%d %H:%M:%S", &tm);
1960 #endif
1961 secs = sn->vm_clock_nsec / 1000000000;
1962 snprintf(clock_buf, sizeof(clock_buf),
1963 "%02d:%02d:%02d.%03d",
1964 (int)(secs / 3600),
1965 (int)((secs / 60) % 60),
1966 (int)(secs % 60),
1967 (int)((sn->vm_clock_nsec / 1000000) % 1000));
1968 snprintf(buf, buf_size,
1969 "%-10s%-20s%7s%20s%15s",
1970 sn->id_str, sn->name,
1971 get_human_readable_size(buf1, sizeof(buf1), sn->vm_state_size),
1972 date_buf,
1973 clock_buf);
1974 }
1975 return buf;
1976 }
1977
1978
1979 /**************************************************************/
1980 /* async I/Os */
1981
1982 BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num,
1983 QEMUIOVector *qiov, int nb_sectors,
1984 BlockDriverCompletionFunc *cb, void *opaque)
1985 {
1986 BlockDriver *drv = bs->drv;
1987 BlockDriverAIOCB *ret;
1988
1989 if (!drv)
1990 return NULL;
1991 if (bdrv_check_request(bs, sector_num, nb_sectors))
1992 return NULL;
1993
1994 ret = drv->bdrv_aio_readv(bs, sector_num, qiov, nb_sectors,
1995 cb, opaque);
1996
1997 if (ret) {
1998 /* Update stats even though technically transfer has not happened. */
1999 bs->rd_bytes += (unsigned) nb_sectors * BDRV_SECTOR_SIZE;
2000 bs->rd_ops ++;
2001 }
2002
2003 return ret;
2004 }
2005
2006 BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num,
2007 QEMUIOVector *qiov, int nb_sectors,
2008 BlockDriverCompletionFunc *cb, void *opaque)
2009 {
2010 BlockDriver *drv = bs->drv;
2011 BlockDriverAIOCB *ret;
2012
2013 if (!drv)
2014 return NULL;
2015 if (bs->read_only)
2016 return NULL;
2017 if (bdrv_check_request(bs, sector_num, nb_sectors))
2018 return NULL;
2019
2020 if (bs->dirty_bitmap) {
2021 set_dirty_bitmap(bs, sector_num, nb_sectors, 1);
2022 }
2023
2024 ret = drv->bdrv_aio_writev(bs, sector_num, qiov, nb_sectors,
2025 cb, opaque);
2026
2027 if (ret) {
2028 /* Update stats even though technically transfer has not happened. */
2029 bs->wr_bytes += (unsigned) nb_sectors * BDRV_SECTOR_SIZE;
2030 bs->wr_ops ++;
2031 if (bs->wr_highest_sector < sector_num + nb_sectors - 1) {
2032 bs->wr_highest_sector = sector_num + nb_sectors - 1;
2033 }
2034 }
2035
2036 return ret;
2037 }
2038
2039
2040 typedef struct MultiwriteCB {
2041 int error;
2042 int num_requests;
2043 int num_callbacks;
2044 struct {
2045 BlockDriverCompletionFunc *cb;
2046 void *opaque;
2047 QEMUIOVector *free_qiov;
2048 void *free_buf;
2049 } callbacks[];
2050 } MultiwriteCB;
2051
2052 static void multiwrite_user_cb(MultiwriteCB *mcb)
2053 {
2054 int i;
2055
2056 for (i = 0; i < mcb->num_callbacks; i++) {
2057 mcb->callbacks[i].cb(mcb->callbacks[i].opaque, mcb->error);
2058 if (mcb->callbacks[i].free_qiov) {
2059 qemu_iovec_destroy(mcb->callbacks[i].free_qiov);
2060 }
2061 qemu_free(mcb->callbacks[i].free_qiov);
2062 qemu_vfree(mcb->callbacks[i].free_buf);
2063 }
2064 }
2065
2066 static void multiwrite_cb(void *opaque, int ret)
2067 {
2068 MultiwriteCB *mcb = opaque;
2069
2070 if (ret < 0 && !mcb->error) {
2071 mcb->error = ret;
2072 }
2073
2074 mcb->num_requests--;
2075 if (mcb->num_requests == 0) {
2076 multiwrite_user_cb(mcb);
2077 qemu_free(mcb);
2078 }
2079 }
2080
2081 static int multiwrite_req_compare(const void *a, const void *b)
2082 {
2083 const BlockRequest *req1 = a, *req2 = b;
2084
2085 /*
2086 * Note that we can't simply subtract req2->sector from req1->sector
2087 * here as that could overflow the return value.
2088 */
2089 if (req1->sector > req2->sector) {
2090 return 1;
2091 } else if (req1->sector < req2->sector) {
2092 return -1;
2093 } else {
2094 return 0;
2095 }
2096 }
2097
2098 /*
2099 * Takes a bunch of requests and tries to merge them. Returns the number of
2100 * requests that remain after merging.
2101 */
2102 static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs,
2103 int num_reqs, MultiwriteCB *mcb)
2104 {
2105 int i, outidx;
2106
2107 // Sort requests by start sector
2108 qsort(reqs, num_reqs, sizeof(*reqs), &multiwrite_req_compare);
2109
2110 // Check if adjacent requests touch the same clusters. If so, combine them,
2111 // filling up gaps with zero sectors.
2112 outidx = 0;
2113 for (i = 1; i < num_reqs; i++) {
2114 int merge = 0;
2115 int64_t oldreq_last = reqs[outidx].sector + reqs[outidx].nb_sectors;
2116
2117 // This handles the cases that are valid for all block drivers, namely
2118 // exactly sequential writes and overlapping writes.
2119 if (reqs[i].sector <= oldreq_last) {
2120 merge = 1;
2121 }
2122
2123 // The block driver may decide that it makes sense to combine requests
2124 // even if there is a gap of some sectors between them. In this case,
2125 // the gap is filled with zeros (therefore only applicable for yet
2126 // unused space in format like qcow2).
2127 if (!merge && bs->drv->bdrv_merge_requests) {
2128 merge = bs->drv->bdrv_merge_requests(bs, &reqs[outidx], &reqs[i]);
2129 }
2130
2131 if (reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1 > IOV_MAX) {
2132 merge = 0;
2133 }
2134
2135 if (merge) {
2136 size_t size;
2137 QEMUIOVector *qiov = qemu_mallocz(sizeof(*qiov));
2138 qemu_iovec_init(qiov,
2139 reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1);
2140
2141 // Add the first request to the merged one. If the requests are
2142 // overlapping, drop the last sectors of the first request.
2143 size = (reqs[i].sector - reqs[outidx].sector) << 9;
2144 qemu_iovec_concat(qiov, reqs[outidx].qiov, size);
2145
2146 // We might need to add some zeros between the two requests
2147 if (reqs[i].sector > oldreq_last) {
2148 size_t zero_bytes = (reqs[i].sector - oldreq_last) << 9;
2149 uint8_t *buf = qemu_blockalign(bs, zero_bytes);
2150 memset(buf, 0, zero_bytes);
2151 qemu_iovec_add(qiov, buf, zero_bytes);
2152 mcb->callbacks[i].free_buf = buf;
2153 }
2154
2155 // Add the second request
2156 qemu_iovec_concat(qiov, reqs[i].qiov, reqs[i].qiov->size);
2157
2158 reqs[outidx].nb_sectors = qiov->size >> 9;
2159 reqs[outidx].qiov = qiov;
2160
2161 mcb->callbacks[i].free_qiov = reqs[outidx].qiov;
2162 } else {
2163 outidx++;
2164 reqs[outidx].sector = reqs[i].sector;
2165 reqs[outidx].nb_sectors = reqs[i].nb_sectors;
2166 reqs[outidx].qiov = reqs[i].qiov;
2167 }
2168 }
2169
2170 return outidx + 1;
2171 }
2172
2173 /*
2174 * Submit multiple AIO write requests at once.
2175 *
2176 * On success, the function returns 0 and all requests in the reqs array have
2177 * been submitted. In error case this function returns -1, and any of the
2178 * requests may or may not be submitted yet. In particular, this means that the
2179 * callback will be called for some of the requests, for others it won't. The
2180 * caller must check the error field of the BlockRequest to wait for the right
2181 * callbacks (if error != 0, no callback will be called).
2182 *
2183 * The implementation may modify the contents of the reqs array, e.g. to merge
2184 * requests. However, the fields opaque and error are left unmodified as they
2185 * are used to signal failure for a single request to the caller.
2186 */
2187 int bdrv_aio_multiwrite(BlockDriverState *bs, BlockRequest *reqs, int num_reqs)
2188 {
2189 BlockDriverAIOCB *acb;
2190 MultiwriteCB *mcb;
2191 int i;
2192
2193 if (num_reqs == 0) {
2194 return 0;
2195 }
2196
2197 // Create MultiwriteCB structure
2198 mcb = qemu_mallocz(sizeof(*mcb) + num_reqs * sizeof(*mcb->callbacks));
2199 mcb->num_requests = 0;
2200 mcb->num_callbacks = num_reqs;
2201
2202 for (i = 0; i < num_reqs; i++) {
2203 mcb->callbacks[i].cb = reqs[i].cb;
2204 mcb->callbacks[i].opaque = reqs[i].opaque;
2205 }
2206
2207 // Check for mergable requests
2208 num_reqs = multiwrite_merge(bs, reqs, num_reqs, mcb);
2209
2210 /*
2211 * Run the aio requests. As soon as one request can't be submitted
2212 * successfully, fail all requests that are not yet submitted (we must
2213 * return failure for all requests anyway)
2214 *
2215 * num_requests cannot be set to the right value immediately: If
2216 * bdrv_aio_writev fails for some request, num_requests would be too high
2217 * and therefore multiwrite_cb() would never recognize the multiwrite
2218 * request as completed. We also cannot use the loop variable i to set it
2219 * when the first request fails because the callback may already have been
2220 * called for previously submitted requests. Thus, num_requests must be
2221 * incremented for each request that is submitted.
2222 *
2223 * The problem that callbacks may be called early also means that we need
2224 * to take care that num_requests doesn't become 0 before all requests are
2225 * submitted - multiwrite_cb() would consider the multiwrite request
2226 * completed. A dummy request that is "completed" by a manual call to
2227 * multiwrite_cb() takes care of this.
2228 */
2229 mcb->num_requests = 1;
2230
2231 for (i = 0; i < num_reqs; i++) {
2232 mcb->num_requests++;
2233 acb = bdrv_aio_writev(bs, reqs[i].sector, reqs[i].qiov,
2234 reqs[i].nb_sectors, multiwrite_cb, mcb);
2235
2236 if (acb == NULL) {
2237 // We can only fail the whole thing if no request has been
2238 // submitted yet. Otherwise we'll wait for the submitted AIOs to
2239 // complete and report the error in the callback.
2240 if (i == 0) {
2241 goto fail;
2242 } else {
2243 multiwrite_cb(mcb, -EIO);
2244 break;
2245 }
2246 }
2247 }
2248
2249 /* Complete the dummy request */
2250 multiwrite_cb(mcb, 0);
2251
2252 return 0;
2253
2254 fail:
2255 for (i = 0; i < mcb->num_callbacks; i++) {
2256 reqs[i].error = -EIO;
2257 }
2258 qemu_free(mcb);
2259 return -1;
2260 }
2261
2262 BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs,
2263 BlockDriverCompletionFunc *cb, void *opaque)
2264 {
2265 BlockDriver *drv = bs->drv;
2266
2267 if (bs->open_flags & BDRV_O_NO_FLUSH) {
2268 return bdrv_aio_noop_em(bs, cb, opaque);
2269 }
2270
2271 if (!drv)
2272 return NULL;
2273 return drv->bdrv_aio_flush(bs, cb, opaque);
2274 }
2275
2276 void bdrv_aio_cancel(BlockDriverAIOCB *acb)
2277 {
2278 acb->pool->cancel(acb);
2279 }
2280
2281
2282 /**************************************************************/
2283 /* async block device emulation */
2284
2285 typedef struct BlockDriverAIOCBSync {
2286 BlockDriverAIOCB common;
2287 QEMUBH *bh;
2288 int ret;
2289 /* vector translation state */
2290 QEMUIOVector *qiov;
2291 uint8_t *bounce;
2292 int is_write;
2293 } BlockDriverAIOCBSync;
2294
2295 static void bdrv_aio_cancel_em(BlockDriverAIOCB *blockacb)
2296 {
2297 BlockDriverAIOCBSync *acb =
2298 container_of(blockacb, BlockDriverAIOCBSync, common);
2299 qemu_bh_delete(acb->bh);
2300 acb->bh = NULL;
2301 qemu_aio_release(acb);
2302 }
2303
2304 static AIOPool bdrv_em_aio_pool = {
2305 .aiocb_size = sizeof(BlockDriverAIOCBSync),
2306 .cancel = bdrv_aio_cancel_em,
2307 };
2308
2309 static void bdrv_aio_bh_cb(void *opaque)
2310 {
2311 BlockDriverAIOCBSync *acb = opaque;
2312
2313 if (!acb->is_write)
2314 qemu_iovec_from_buffer(acb->qiov, acb->bounce, acb->qiov->size);
2315 qemu_vfree(acb->bounce);
2316 acb->common.cb(acb->common.opaque, acb->ret);
2317 qemu_bh_delete(acb->bh);
2318 acb->bh = NULL;
2319 qemu_aio_release(acb);
2320 }
2321
2322 static BlockDriverAIOCB *bdrv_aio_rw_vector(BlockDriverState *bs,
2323 int64_t sector_num,
2324 QEMUIOVector *qiov,
2325 int nb_sectors,
2326 BlockDriverCompletionFunc *cb,
2327 void *opaque,
2328 int is_write)
2329
2330 {
2331 BlockDriverAIOCBSync *acb;
2332
2333 acb = qemu_aio_get(&bdrv_em_aio_pool, bs, cb, opaque);
2334 acb->is_write = is_write;
2335 acb->qiov = qiov;
2336 acb->bounce = qemu_blockalign(bs, qiov->size);
2337
2338 if (!acb->bh)
2339 acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb);
2340
2341 if (is_write) {
2342 qemu_iovec_to_buffer(acb->qiov, acb->bounce);
2343 acb->ret = bdrv_write(bs, sector_num, acb->bounce, nb_sectors);
2344 } else {
2345 acb->ret = bdrv_read(bs, sector_num, acb->bounce, nb_sectors);
2346 }
2347
2348 qemu_bh_schedule(acb->bh);
2349
2350 return &acb->common;
2351 }
2352
2353 static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs,
2354 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
2355 BlockDriverCompletionFunc *cb, void *opaque)
2356 {
2357 return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
2358 }
2359
2360 static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs,
2361 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
2362 BlockDriverCompletionFunc *cb, void *opaque)
2363 {
2364 return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
2365 }
2366
2367 static BlockDriverAIOCB *bdrv_aio_flush_em(BlockDriverState *bs,
2368 BlockDriverCompletionFunc *cb, void *opaque)
2369 {
2370 BlockDriverAIOCBSync *acb;
2371
2372 acb = qemu_aio_get(&bdrv_em_aio_pool, bs, cb, opaque);
2373 acb->is_write = 1; /* don't bounce in the completion hadler */
2374 acb->qiov = NULL;
2375 acb->bounce = NULL;
2376 acb->ret = 0;
2377
2378 if (!acb->bh)
2379 acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb);
2380
2381 bdrv_flush(bs);
2382 qemu_bh_schedule(acb->bh);
2383 return &acb->common;
2384 }
2385
2386 static BlockDriverAIOCB *bdrv_aio_noop_em(BlockDriverState *bs,
2387 BlockDriverCompletionFunc *cb, void *opaque)
2388 {
2389 BlockDriverAIOCBSync *acb;
2390
2391 acb = qemu_aio_get(&bdrv_em_aio_pool, bs, cb, opaque);
2392 acb->is_write = 1; /* don't bounce in the completion handler */
2393 acb->qiov = NULL;
2394 acb->bounce = NULL;
2395 acb->ret = 0;
2396
2397 if (!acb->bh) {
2398 acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb);
2399 }
2400
2401 qemu_bh_schedule(acb->bh);
2402 return &acb->common;
2403 }
2404
2405 /**************************************************************/
2406 /* sync block device emulation */
2407
2408 static void bdrv_rw_em_cb(void *opaque, int ret)
2409 {
2410 *(int *)opaque = ret;
2411 }
2412
2413 #define NOT_DONE 0x7fffffff
2414
2415 static int bdrv_read_em(BlockDriverState *bs, int64_t sector_num,
2416 uint8_t *buf, int nb_sectors)
2417 {
2418 int async_ret;
2419 BlockDriverAIOCB *acb;
2420 struct iovec iov;
2421 QEMUIOVector qiov;
2422
2423 async_context_push();
2424
2425 async_ret = NOT_DONE;
2426 iov.iov_base = (void *)buf;
2427 iov.iov_len = nb_sectors * BDRV_SECTOR_SIZE;
2428 qemu_iovec_init_external(&qiov, &iov, 1);
2429 acb = bdrv_aio_readv(bs, sector_num, &qiov, nb_sectors,
2430 bdrv_rw_em_cb, &async_ret);
2431 if (acb == NULL) {
2432 async_ret = -1;
2433 goto fail;
2434 }
2435
2436 while (async_ret == NOT_DONE) {
2437 qemu_aio_wait();
2438 }
2439
2440
2441 fail:
2442 async_context_pop();
2443 return async_ret;
2444 }
2445
2446 static int bdrv_write_em(BlockDriverState *bs, int64_t sector_num,
2447 const uint8_t *buf, int nb_sectors)
2448 {
2449 int async_ret;
2450 BlockDriverAIOCB *acb;
2451 struct iovec iov;
2452 QEMUIOVector qiov;
2453
2454 async_context_push();
2455
2456 async_ret = NOT_DONE;
2457 iov.iov_base = (void *)buf;
2458 iov.iov_len = nb_sectors * BDRV_SECTOR_SIZE;
2459 qemu_iovec_init_external(&qiov, &iov, 1);
2460 acb = bdrv_aio_writev(bs, sector_num, &qiov, nb_sectors,
2461 bdrv_rw_em_cb, &async_ret);
2462 if (acb == NULL) {
2463 async_ret = -1;
2464 goto fail;
2465 }
2466 while (async_ret == NOT_DONE) {
2467 qemu_aio_wait();
2468 }
2469
2470 fail:
2471 async_context_pop();
2472 return async_ret;
2473 }
2474
2475 void bdrv_init(void)
2476 {
2477 module_call_init(MODULE_INIT_BLOCK);
2478 }
2479
2480 void bdrv_init_with_whitelist(void)
2481 {
2482 use_bdrv_whitelist = 1;
2483 bdrv_init();
2484 }
2485
2486 void *qemu_aio_get(AIOPool *pool, BlockDriverState *bs,
2487 BlockDriverCompletionFunc *cb, void *opaque)
2488 {
2489 BlockDriverAIOCB *acb;
2490
2491 if (pool->free_aiocb) {
2492 acb = pool->free_aiocb;
2493 pool->free_aiocb = acb->next;
2494 } else {
2495 acb = qemu_mallocz(pool->aiocb_size);
2496 acb->pool = pool;
2497 }
2498 acb->bs = bs;
2499 acb->cb = cb;
2500 acb->opaque = opaque;
2501 return acb;
2502 }
2503
2504 void qemu_aio_release(void *p)
2505 {
2506 BlockDriverAIOCB *acb = (BlockDriverAIOCB *)p;
2507 AIOPool *pool = acb->pool;
2508 acb->next = pool->free_aiocb;
2509 pool->free_aiocb = acb;
2510 }
2511
2512 /**************************************************************/
2513 /* removable device support */
2514
2515 /**
2516 * Return TRUE if the media is present
2517 */
2518 int bdrv_is_inserted(BlockDriverState *bs)
2519 {
2520 BlockDriver *drv = bs->drv;
2521 int ret;
2522 if (!drv)
2523 return 0;
2524 if (!drv->bdrv_is_inserted)
2525 return !bs->tray_open;
2526 ret = drv->bdrv_is_inserted(bs);
2527 return ret;
2528 }
2529
2530 /**
2531 * Return TRUE if the media changed since the last call to this
2532 * function. It is currently only used for floppy disks
2533 */
2534 int bdrv_media_changed(BlockDriverState *bs)
2535 {
2536 BlockDriver *drv = bs->drv;
2537 int ret;
2538
2539 if (!drv || !drv->bdrv_media_changed)
2540 ret = -ENOTSUP;
2541 else
2542 ret = drv->bdrv_media_changed(bs);
2543 if (ret == -ENOTSUP)
2544 ret = bs->media_changed;
2545 bs->media_changed = 0;
2546 return ret;
2547 }
2548
2549 /**
2550 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
2551 */
2552 int bdrv_eject(BlockDriverState *bs, int eject_flag)
2553 {
2554 BlockDriver *drv = bs->drv;
2555 int ret;
2556
2557 if (bs->locked) {
2558 return -EBUSY;
2559 }
2560
2561 if (!drv || !drv->bdrv_eject) {
2562 ret = -ENOTSUP;
2563 } else {
2564 ret = drv->bdrv_eject(bs, eject_flag);
2565 }
2566 if (ret == -ENOTSUP) {
2567 ret = 0;
2568 }
2569 if (ret >= 0) {
2570 bs->tray_open = eject_flag;
2571 }
2572
2573 return ret;
2574 }
2575
2576 int bdrv_is_locked(BlockDriverState *bs)
2577 {
2578 return bs->locked;
2579 }
2580
2581 /**
2582 * Lock or unlock the media (if it is locked, the user won't be able
2583 * to eject it manually).
2584 */
2585 void bdrv_set_locked(BlockDriverState *bs, int locked)
2586 {
2587 BlockDriver *drv = bs->drv;
2588
2589 bs->locked = locked;
2590 if (drv && drv->bdrv_set_locked) {
2591 drv->bdrv_set_locked(bs, locked);
2592 }
2593 }
2594
2595 /* needed for generic scsi interface */
2596
2597 int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
2598 {
2599 BlockDriver *drv = bs->drv;
2600
2601 if (drv && drv->bdrv_ioctl)
2602 return drv->bdrv_ioctl(bs, req, buf);
2603 return -ENOTSUP;
2604 }
2605
2606 BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs,
2607 unsigned long int req, void *buf,
2608 BlockDriverCompletionFunc *cb, void *opaque)
2609 {
2610 BlockDriver *drv = bs->drv;
2611
2612 if (drv && drv->bdrv_aio_ioctl)
2613 return drv->bdrv_aio_ioctl(bs, req, buf, cb, opaque);
2614 return NULL;
2615 }
2616
2617
2618
2619 void *qemu_blockalign(BlockDriverState *bs, size_t size)
2620 {
2621 return qemu_memalign((bs && bs->buffer_alignment) ? bs->buffer_alignment : 512, size);
2622 }
2623
2624 void bdrv_set_dirty_tracking(BlockDriverState *bs, int enable)
2625 {
2626 int64_t bitmap_size;
2627
2628 bs->dirty_count = 0;
2629 if (enable) {
2630 if (!bs->dirty_bitmap) {
2631 bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS) +
2632 BDRV_SECTORS_PER_DIRTY_CHUNK * 8 - 1;
2633 bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * 8;
2634
2635 bs->dirty_bitmap = qemu_mallocz(bitmap_size);
2636 }
2637 } else {
2638 if (bs->dirty_bitmap) {
2639 qemu_free(bs->dirty_bitmap);
2640 bs->dirty_bitmap = NULL;
2641 }
2642 }
2643 }
2644
2645 int bdrv_get_dirty(BlockDriverState *bs, int64_t sector)
2646 {
2647 int64_t chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK;
2648
2649 if (bs->dirty_bitmap &&
2650 (sector << BDRV_SECTOR_BITS) < bdrv_getlength(bs)) {
2651 return bs->dirty_bitmap[chunk / (sizeof(unsigned long) * 8)] &
2652 (1 << (chunk % (sizeof(unsigned long) * 8)));
2653 } else {
2654 return 0;
2655 }
2656 }
2657
2658 void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector,
2659 int nr_sectors)
2660 {
2661 set_dirty_bitmap(bs, cur_sector, nr_sectors, 0);
2662 }
2663
2664 int64_t bdrv_get_dirty_count(BlockDriverState *bs)
2665 {
2666 return bs->dirty_count;
2667 }
Zhi Yong Wu's QEmu Source Tree - dev