ppc/pnv: add a PnvICPState object
[qemu.git] / block.c
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 "qemu/osdep.h"
25 #include "block/trace.h"
26 #include "block/block_int.h"
27 #include "block/blockjob.h"
28 #include "block/nbd.h"
29 #include "qemu/error-report.h"
30 #include "module_block.h"
31 #include "qemu/module.h"
32 #include "qapi/qmp/qerror.h"
33 #include "qapi/qmp/qbool.h"
34 #include "qapi/qmp/qjson.h"
35 #include "sysemu/block-backend.h"
36 #include "sysemu/sysemu.h"
37 #include "qemu/notify.h"
38 #include "qemu/coroutine.h"
39 #include "block/qapi.h"
40 #include "qmp-commands.h"
41 #include "qemu/timer.h"
42 #include "qapi-event.h"
43 #include "qemu/cutils.h"
44 #include "qemu/id.h"
45 #include "qapi/util.h"
46
47 #ifdef CONFIG_BSD
48 #include <sys/ioctl.h>
49 #include <sys/queue.h>
50 #ifndef __DragonFly__
51 #include <sys/disk.h>
52 #endif
53 #endif
54
55 #ifdef _WIN32
56 #include <windows.h>
57 #endif
58
59 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
60
61 static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states =
62 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states);
63
64 static QTAILQ_HEAD(, BlockDriverState) all_bdrv_states =
65 QTAILQ_HEAD_INITIALIZER(all_bdrv_states);
66
67 static QLIST_HEAD(, BlockDriver) bdrv_drivers =
68 QLIST_HEAD_INITIALIZER(bdrv_drivers);
69
70 static BlockDriverState *bdrv_open_inherit(const char *filename,
71 const char *reference,
72 QDict *options, int flags,
73 BlockDriverState *parent,
74 const BdrvChildRole *child_role,
75 Error **errp);
76
77 /* If non-zero, use only whitelisted block drivers */
78 static int use_bdrv_whitelist;
79
80 #ifdef _WIN32
81 static int is_windows_drive_prefix(const char *filename)
82 {
83 return (((filename[0] >= 'a' && filename[0] <= 'z') ||
84 (filename[0] >= 'A' && filename[0] <= 'Z')) &&
85 filename[1] == ':');
86 }
87
88 int is_windows_drive(const char *filename)
89 {
90 if (is_windows_drive_prefix(filename) &&
91 filename[2] == '\0')
92 return 1;
93 if (strstart(filename, "\\\\.\\", NULL) ||
94 strstart(filename, "//./", NULL))
95 return 1;
96 return 0;
97 }
98 #endif
99
100 size_t bdrv_opt_mem_align(BlockDriverState *bs)
101 {
102 if (!bs || !bs->drv) {
103 /* page size or 4k (hdd sector size) should be on the safe side */
104 return MAX(4096, getpagesize());
105 }
106
107 return bs->bl.opt_mem_alignment;
108 }
109
110 size_t bdrv_min_mem_align(BlockDriverState *bs)
111 {
112 if (!bs || !bs->drv) {
113 /* page size or 4k (hdd sector size) should be on the safe side */
114 return MAX(4096, getpagesize());
115 }
116
117 return bs->bl.min_mem_alignment;
118 }
119
120 /* check if the path starts with "<protocol>:" */
121 int path_has_protocol(const char *path)
122 {
123 const char *p;
124
125 #ifdef _WIN32
126 if (is_windows_drive(path) ||
127 is_windows_drive_prefix(path)) {
128 return 0;
129 }
130 p = path + strcspn(path, ":/\\");
131 #else
132 p = path + strcspn(path, ":/");
133 #endif
134
135 return *p == ':';
136 }
137
138 int path_is_absolute(const char *path)
139 {
140 #ifdef _WIN32
141 /* specific case for names like: "\\.\d:" */
142 if (is_windows_drive(path) || is_windows_drive_prefix(path)) {
143 return 1;
144 }
145 return (*path == '/' || *path == '\\');
146 #else
147 return (*path == '/');
148 #endif
149 }
150
151 /* if filename is absolute, just copy it to dest. Otherwise, build a
152 path to it by considering it is relative to base_path. URL are
153 supported. */
154 void path_combine(char *dest, int dest_size,
155 const char *base_path,
156 const char *filename)
157 {
158 const char *p, *p1;
159 int len;
160
161 if (dest_size <= 0)
162 return;
163 if (path_is_absolute(filename)) {
164 pstrcpy(dest, dest_size, filename);
165 } else {
166 p = strchr(base_path, ':');
167 if (p)
168 p++;
169 else
170 p = base_path;
171 p1 = strrchr(base_path, '/');
172 #ifdef _WIN32
173 {
174 const char *p2;
175 p2 = strrchr(base_path, '\\');
176 if (!p1 || p2 > p1)
177 p1 = p2;
178 }
179 #endif
180 if (p1)
181 p1++;
182 else
183 p1 = base_path;
184 if (p1 > p)
185 p = p1;
186 len = p - base_path;
187 if (len > dest_size - 1)
188 len = dest_size - 1;
189 memcpy(dest, base_path, len);
190 dest[len] = '\0';
191 pstrcat(dest, dest_size, filename);
192 }
193 }
194
195 bool bdrv_is_read_only(BlockDriverState *bs)
196 {
197 return bs->read_only;
198 }
199
200 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
201 {
202 /* Do not set read_only if copy_on_read is enabled */
203 if (bs->copy_on_read && read_only) {
204 error_setg(errp, "Can't set node '%s' to r/o with copy-on-read enabled",
205 bdrv_get_device_or_node_name(bs));
206 return -EINVAL;
207 }
208
209 /* Do not clear read_only if it is prohibited */
210 if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR)) {
211 error_setg(errp, "Node '%s' is read only",
212 bdrv_get_device_or_node_name(bs));
213 return -EPERM;
214 }
215
216 return 0;
217 }
218
219 int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
220 {
221 int ret = 0;
222
223 ret = bdrv_can_set_read_only(bs, read_only, errp);
224 if (ret < 0) {
225 return ret;
226 }
227
228 bs->read_only = read_only;
229 return 0;
230 }
231
232 void bdrv_get_full_backing_filename_from_filename(const char *backed,
233 const char *backing,
234 char *dest, size_t sz,
235 Error **errp)
236 {
237 if (backing[0] == '\0' || path_has_protocol(backing) ||
238 path_is_absolute(backing))
239 {
240 pstrcpy(dest, sz, backing);
241 } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) {
242 error_setg(errp, "Cannot use relative backing file names for '%s'",
243 backed);
244 } else {
245 path_combine(dest, sz, backed, backing);
246 }
247 }
248
249 void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz,
250 Error **errp)
251 {
252 char *backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename;
253
254 bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file,
255 dest, sz, errp);
256 }
257
258 void bdrv_register(BlockDriver *bdrv)
259 {
260 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list);
261 }
262
263 BlockDriverState *bdrv_new(void)
264 {
265 BlockDriverState *bs;
266 int i;
267
268 bs = g_new0(BlockDriverState, 1);
269 QLIST_INIT(&bs->dirty_bitmaps);
270 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
271 QLIST_INIT(&bs->op_blockers[i]);
272 }
273 notifier_with_return_list_init(&bs->before_write_notifiers);
274 bs->refcnt = 1;
275 bs->aio_context = qemu_get_aio_context();
276
277 qemu_co_queue_init(&bs->flush_queue);
278
279 QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list);
280
281 return bs;
282 }
283
284 static BlockDriver *bdrv_do_find_format(const char *format_name)
285 {
286 BlockDriver *drv1;
287
288 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
289 if (!strcmp(drv1->format_name, format_name)) {
290 return drv1;
291 }
292 }
293
294 return NULL;
295 }
296
297 BlockDriver *bdrv_find_format(const char *format_name)
298 {
299 BlockDriver *drv1;
300 int i;
301
302 drv1 = bdrv_do_find_format(format_name);
303 if (drv1) {
304 return drv1;
305 }
306
307 /* The driver isn't registered, maybe we need to load a module */
308 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
309 if (!strcmp(block_driver_modules[i].format_name, format_name)) {
310 block_module_load_one(block_driver_modules[i].library_name);
311 break;
312 }
313 }
314
315 return bdrv_do_find_format(format_name);
316 }
317
318 static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
319 {
320 static const char *whitelist_rw[] = {
321 CONFIG_BDRV_RW_WHITELIST
322 };
323 static const char *whitelist_ro[] = {
324 CONFIG_BDRV_RO_WHITELIST
325 };
326 const char **p;
327
328 if (!whitelist_rw[0] && !whitelist_ro[0]) {
329 return 1; /* no whitelist, anything goes */
330 }
331
332 for (p = whitelist_rw; *p; p++) {
333 if (!strcmp(drv->format_name, *p)) {
334 return 1;
335 }
336 }
337 if (read_only) {
338 for (p = whitelist_ro; *p; p++) {
339 if (!strcmp(drv->format_name, *p)) {
340 return 1;
341 }
342 }
343 }
344 return 0;
345 }
346
347 bool bdrv_uses_whitelist(void)
348 {
349 return use_bdrv_whitelist;
350 }
351
352 typedef struct CreateCo {
353 BlockDriver *drv;
354 char *filename;
355 QemuOpts *opts;
356 int ret;
357 Error *err;
358 } CreateCo;
359
360 static void coroutine_fn bdrv_create_co_entry(void *opaque)
361 {
362 Error *local_err = NULL;
363 int ret;
364
365 CreateCo *cco = opaque;
366 assert(cco->drv);
367
368 ret = cco->drv->bdrv_create(cco->filename, cco->opts, &local_err);
369 error_propagate(&cco->err, local_err);
370 cco->ret = ret;
371 }
372
373 int bdrv_create(BlockDriver *drv, const char* filename,
374 QemuOpts *opts, Error **errp)
375 {
376 int ret;
377
378 Coroutine *co;
379 CreateCo cco = {
380 .drv = drv,
381 .filename = g_strdup(filename),
382 .opts = opts,
383 .ret = NOT_DONE,
384 .err = NULL,
385 };
386
387 if (!drv->bdrv_create) {
388 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name);
389 ret = -ENOTSUP;
390 goto out;
391 }
392
393 if (qemu_in_coroutine()) {
394 /* Fast-path if already in coroutine context */
395 bdrv_create_co_entry(&cco);
396 } else {
397 co = qemu_coroutine_create(bdrv_create_co_entry, &cco);
398 qemu_coroutine_enter(co);
399 while (cco.ret == NOT_DONE) {
400 aio_poll(qemu_get_aio_context(), true);
401 }
402 }
403
404 ret = cco.ret;
405 if (ret < 0) {
406 if (cco.err) {
407 error_propagate(errp, cco.err);
408 } else {
409 error_setg_errno(errp, -ret, "Could not create image");
410 }
411 }
412
413 out:
414 g_free(cco.filename);
415 return ret;
416 }
417
418 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
419 {
420 BlockDriver *drv;
421 Error *local_err = NULL;
422 int ret;
423
424 drv = bdrv_find_protocol(filename, true, errp);
425 if (drv == NULL) {
426 return -ENOENT;
427 }
428
429 ret = bdrv_create(drv, filename, opts, &local_err);
430 error_propagate(errp, local_err);
431 return ret;
432 }
433
434 /**
435 * Try to get @bs's logical and physical block size.
436 * On success, store them in @bsz struct and return 0.
437 * On failure return -errno.
438 * @bs must not be empty.
439 */
440 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
441 {
442 BlockDriver *drv = bs->drv;
443
444 if (drv && drv->bdrv_probe_blocksizes) {
445 return drv->bdrv_probe_blocksizes(bs, bsz);
446 }
447
448 return -ENOTSUP;
449 }
450
451 /**
452 * Try to get @bs's geometry (cyls, heads, sectors).
453 * On success, store them in @geo struct and return 0.
454 * On failure return -errno.
455 * @bs must not be empty.
456 */
457 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
458 {
459 BlockDriver *drv = bs->drv;
460
461 if (drv && drv->bdrv_probe_geometry) {
462 return drv->bdrv_probe_geometry(bs, geo);
463 }
464
465 return -ENOTSUP;
466 }
467
468 /*
469 * Create a uniquely-named empty temporary file.
470 * Return 0 upon success, otherwise a negative errno value.
471 */
472 int get_tmp_filename(char *filename, int size)
473 {
474 #ifdef _WIN32
475 char temp_dir[MAX_PATH];
476 /* GetTempFileName requires that its output buffer (4th param)
477 have length MAX_PATH or greater. */
478 assert(size >= MAX_PATH);
479 return (GetTempPath(MAX_PATH, temp_dir)
480 && GetTempFileName(temp_dir, "qem", 0, filename)
481 ? 0 : -GetLastError());
482 #else
483 int fd;
484 const char *tmpdir;
485 tmpdir = getenv("TMPDIR");
486 if (!tmpdir) {
487 tmpdir = "/var/tmp";
488 }
489 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) {
490 return -EOVERFLOW;
491 }
492 fd = mkstemp(filename);
493 if (fd < 0) {
494 return -errno;
495 }
496 if (close(fd) != 0) {
497 unlink(filename);
498 return -errno;
499 }
500 return 0;
501 #endif
502 }
503
504 /*
505 * Detect host devices. By convention, /dev/cdrom[N] is always
506 * recognized as a host CDROM.
507 */
508 static BlockDriver *find_hdev_driver(const char *filename)
509 {
510 int score_max = 0, score;
511 BlockDriver *drv = NULL, *d;
512
513 QLIST_FOREACH(d, &bdrv_drivers, list) {
514 if (d->bdrv_probe_device) {
515 score = d->bdrv_probe_device(filename);
516 if (score > score_max) {
517 score_max = score;
518 drv = d;
519 }
520 }
521 }
522
523 return drv;
524 }
525
526 static BlockDriver *bdrv_do_find_protocol(const char *protocol)
527 {
528 BlockDriver *drv1;
529
530 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
531 if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) {
532 return drv1;
533 }
534 }
535
536 return NULL;
537 }
538
539 BlockDriver *bdrv_find_protocol(const char *filename,
540 bool allow_protocol_prefix,
541 Error **errp)
542 {
543 BlockDriver *drv1;
544 char protocol[128];
545 int len;
546 const char *p;
547 int i;
548
549 /* TODO Drivers without bdrv_file_open must be specified explicitly */
550
551 /*
552 * XXX(hch): we really should not let host device detection
553 * override an explicit protocol specification, but moving this
554 * later breaks access to device names with colons in them.
555 * Thanks to the brain-dead persistent naming schemes on udev-
556 * based Linux systems those actually are quite common.
557 */
558 drv1 = find_hdev_driver(filename);
559 if (drv1) {
560 return drv1;
561 }
562
563 if (!path_has_protocol(filename) || !allow_protocol_prefix) {
564 return &bdrv_file;
565 }
566
567 p = strchr(filename, ':');
568 assert(p != NULL);
569 len = p - filename;
570 if (len > sizeof(protocol) - 1)
571 len = sizeof(protocol) - 1;
572 memcpy(protocol, filename, len);
573 protocol[len] = '\0';
574
575 drv1 = bdrv_do_find_protocol(protocol);
576 if (drv1) {
577 return drv1;
578 }
579
580 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
581 if (block_driver_modules[i].protocol_name &&
582 !strcmp(block_driver_modules[i].protocol_name, protocol)) {
583 block_module_load_one(block_driver_modules[i].library_name);
584 break;
585 }
586 }
587
588 drv1 = bdrv_do_find_protocol(protocol);
589 if (!drv1) {
590 error_setg(errp, "Unknown protocol '%s'", protocol);
591 }
592 return drv1;
593 }
594
595 /*
596 * Guess image format by probing its contents.
597 * This is not a good idea when your image is raw (CVE-2008-2004), but
598 * we do it anyway for backward compatibility.
599 *
600 * @buf contains the image's first @buf_size bytes.
601 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
602 * but can be smaller if the image file is smaller)
603 * @filename is its filename.
604 *
605 * For all block drivers, call the bdrv_probe() method to get its
606 * probing score.
607 * Return the first block driver with the highest probing score.
608 */
609 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
610 const char *filename)
611 {
612 int score_max = 0, score;
613 BlockDriver *drv = NULL, *d;
614
615 QLIST_FOREACH(d, &bdrv_drivers, list) {
616 if (d->bdrv_probe) {
617 score = d->bdrv_probe(buf, buf_size, filename);
618 if (score > score_max) {
619 score_max = score;
620 drv = d;
621 }
622 }
623 }
624
625 return drv;
626 }
627
628 static int find_image_format(BlockBackend *file, const char *filename,
629 BlockDriver **pdrv, Error **errp)
630 {
631 BlockDriver *drv;
632 uint8_t buf[BLOCK_PROBE_BUF_SIZE];
633 int ret = 0;
634
635 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
636 if (blk_is_sg(file) || !blk_is_inserted(file) || blk_getlength(file) == 0) {
637 *pdrv = &bdrv_raw;
638 return ret;
639 }
640
641 ret = blk_pread(file, 0, buf, sizeof(buf));
642 if (ret < 0) {
643 error_setg_errno(errp, -ret, "Could not read image for determining its "
644 "format");
645 *pdrv = NULL;
646 return ret;
647 }
648
649 drv = bdrv_probe_all(buf, ret, filename);
650 if (!drv) {
651 error_setg(errp, "Could not determine image format: No compatible "
652 "driver found");
653 ret = -ENOENT;
654 }
655 *pdrv = drv;
656 return ret;
657 }
658
659 /**
660 * Set the current 'total_sectors' value
661 * Return 0 on success, -errno on error.
662 */
663 static int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
664 {
665 BlockDriver *drv = bs->drv;
666
667 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
668 if (bdrv_is_sg(bs))
669 return 0;
670
671 /* query actual device if possible, otherwise just trust the hint */
672 if (drv->bdrv_getlength) {
673 int64_t length = drv->bdrv_getlength(bs);
674 if (length < 0) {
675 return length;
676 }
677 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE);
678 }
679
680 bs->total_sectors = hint;
681 return 0;
682 }
683
684 /**
685 * Combines a QDict of new block driver @options with any missing options taken
686 * from @old_options, so that leaving out an option defaults to its old value.
687 */
688 static void bdrv_join_options(BlockDriverState *bs, QDict *options,
689 QDict *old_options)
690 {
691 if (bs->drv && bs->drv->bdrv_join_options) {
692 bs->drv->bdrv_join_options(options, old_options);
693 } else {
694 qdict_join(options, old_options, false);
695 }
696 }
697
698 /**
699 * Set open flags for a given discard mode
700 *
701 * Return 0 on success, -1 if the discard mode was invalid.
702 */
703 int bdrv_parse_discard_flags(const char *mode, int *flags)
704 {
705 *flags &= ~BDRV_O_UNMAP;
706
707 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) {
708 /* do nothing */
709 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) {
710 *flags |= BDRV_O_UNMAP;
711 } else {
712 return -1;
713 }
714
715 return 0;
716 }
717
718 /**
719 * Set open flags for a given cache mode
720 *
721 * Return 0 on success, -1 if the cache mode was invalid.
722 */
723 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough)
724 {
725 *flags &= ~BDRV_O_CACHE_MASK;
726
727 if (!strcmp(mode, "off") || !strcmp(mode, "none")) {
728 *writethrough = false;
729 *flags |= BDRV_O_NOCACHE;
730 } else if (!strcmp(mode, "directsync")) {
731 *writethrough = true;
732 *flags |= BDRV_O_NOCACHE;
733 } else if (!strcmp(mode, "writeback")) {
734 *writethrough = false;
735 } else if (!strcmp(mode, "unsafe")) {
736 *writethrough = false;
737 *flags |= BDRV_O_NO_FLUSH;
738 } else if (!strcmp(mode, "writethrough")) {
739 *writethrough = true;
740 } else {
741 return -1;
742 }
743
744 return 0;
745 }
746
747 static char *bdrv_child_get_parent_desc(BdrvChild *c)
748 {
749 BlockDriverState *parent = c->opaque;
750 return g_strdup(bdrv_get_device_or_node_name(parent));
751 }
752
753 static void bdrv_child_cb_drained_begin(BdrvChild *child)
754 {
755 BlockDriverState *bs = child->opaque;
756 bdrv_drained_begin(bs);
757 }
758
759 static void bdrv_child_cb_drained_end(BdrvChild *child)
760 {
761 BlockDriverState *bs = child->opaque;
762 bdrv_drained_end(bs);
763 }
764
765 /*
766 * Returns the options and flags that a temporary snapshot should get, based on
767 * the originally requested flags (the originally requested image will have
768 * flags like a backing file)
769 */
770 static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
771 int parent_flags, QDict *parent_options)
772 {
773 *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY;
774
775 /* For temporary files, unconditional cache=unsafe is fine */
776 qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off");
777 qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
778
779 /* Copy the read-only option from the parent */
780 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
781
782 /* aio=native doesn't work for cache.direct=off, so disable it for the
783 * temporary snapshot */
784 *child_flags &= ~BDRV_O_NATIVE_AIO;
785 }
786
787 /*
788 * Returns the options and flags that bs->file should get if a protocol driver
789 * is expected, based on the given options and flags for the parent BDS
790 */
791 static void bdrv_inherited_options(int *child_flags, QDict *child_options,
792 int parent_flags, QDict *parent_options)
793 {
794 int flags = parent_flags;
795
796 /* Enable protocol handling, disable format probing for bs->file */
797 flags |= BDRV_O_PROTOCOL;
798
799 /* If the cache mode isn't explicitly set, inherit direct and no-flush from
800 * the parent. */
801 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
802 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
803
804 /* Inherit the read-only option from the parent if it's not set */
805 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
806
807 /* Our block drivers take care to send flushes and respect unmap policy,
808 * so we can default to enable both on lower layers regardless of the
809 * corresponding parent options. */
810 qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap");
811
812 /* Clear flags that only apply to the top layer */
813 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ |
814 BDRV_O_NO_IO);
815
816 *child_flags = flags;
817 }
818
819 const BdrvChildRole child_file = {
820 .get_parent_desc = bdrv_child_get_parent_desc,
821 .inherit_options = bdrv_inherited_options,
822 .drained_begin = bdrv_child_cb_drained_begin,
823 .drained_end = bdrv_child_cb_drained_end,
824 };
825
826 /*
827 * Returns the options and flags that bs->file should get if the use of formats
828 * (and not only protocols) is permitted for it, based on the given options and
829 * flags for the parent BDS
830 */
831 static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options,
832 int parent_flags, QDict *parent_options)
833 {
834 child_file.inherit_options(child_flags, child_options,
835 parent_flags, parent_options);
836
837 *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO);
838 }
839
840 const BdrvChildRole child_format = {
841 .get_parent_desc = bdrv_child_get_parent_desc,
842 .inherit_options = bdrv_inherited_fmt_options,
843 .drained_begin = bdrv_child_cb_drained_begin,
844 .drained_end = bdrv_child_cb_drained_end,
845 };
846
847 static void bdrv_backing_attach(BdrvChild *c)
848 {
849 BlockDriverState *parent = c->opaque;
850 BlockDriverState *backing_hd = c->bs;
851
852 assert(!parent->backing_blocker);
853 error_setg(&parent->backing_blocker,
854 "node is used as backing hd of '%s'",
855 bdrv_get_device_or_node_name(parent));
856
857 parent->open_flags &= ~BDRV_O_NO_BACKING;
858 pstrcpy(parent->backing_file, sizeof(parent->backing_file),
859 backing_hd->filename);
860 pstrcpy(parent->backing_format, sizeof(parent->backing_format),
861 backing_hd->drv ? backing_hd->drv->format_name : "");
862
863 bdrv_op_block_all(backing_hd, parent->backing_blocker);
864 /* Otherwise we won't be able to commit or stream */
865 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,
866 parent->backing_blocker);
867 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_STREAM,
868 parent->backing_blocker);
869 /*
870 * We do backup in 3 ways:
871 * 1. drive backup
872 * The target bs is new opened, and the source is top BDS
873 * 2. blockdev backup
874 * Both the source and the target are top BDSes.
875 * 3. internal backup(used for block replication)
876 * Both the source and the target are backing file
877 *
878 * In case 1 and 2, neither the source nor the target is the backing file.
879 * In case 3, we will block the top BDS, so there is only one block job
880 * for the top BDS and its backing chain.
881 */
882 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_SOURCE,
883 parent->backing_blocker);
884 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_TARGET,
885 parent->backing_blocker);
886 }
887
888 static void bdrv_backing_detach(BdrvChild *c)
889 {
890 BlockDriverState *parent = c->opaque;
891
892 assert(parent->backing_blocker);
893 bdrv_op_unblock_all(c->bs, parent->backing_blocker);
894 error_free(parent->backing_blocker);
895 parent->backing_blocker = NULL;
896 }
897
898 /*
899 * Returns the options and flags that bs->backing should get, based on the
900 * given options and flags for the parent BDS
901 */
902 static void bdrv_backing_options(int *child_flags, QDict *child_options,
903 int parent_flags, QDict *parent_options)
904 {
905 int flags = parent_flags;
906
907 /* The cache mode is inherited unmodified for backing files; except WCE,
908 * which is only applied on the top level (BlockBackend) */
909 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
910 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
911
912 /* backing files always opened read-only */
913 qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on");
914 flags &= ~BDRV_O_COPY_ON_READ;
915
916 /* snapshot=on is handled on the top layer */
917 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY);
918
919 *child_flags = flags;
920 }
921
922 const BdrvChildRole child_backing = {
923 .get_parent_desc = bdrv_child_get_parent_desc,
924 .attach = bdrv_backing_attach,
925 .detach = bdrv_backing_detach,
926 .inherit_options = bdrv_backing_options,
927 .drained_begin = bdrv_child_cb_drained_begin,
928 .drained_end = bdrv_child_cb_drained_end,
929 };
930
931 static int bdrv_open_flags(BlockDriverState *bs, int flags)
932 {
933 int open_flags = flags;
934
935 /*
936 * Clear flags that are internal to the block layer before opening the
937 * image.
938 */
939 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL);
940
941 /*
942 * Snapshots should be writable.
943 */
944 if (flags & BDRV_O_TEMPORARY) {
945 open_flags |= BDRV_O_RDWR;
946 }
947
948 return open_flags;
949 }
950
951 static void update_flags_from_options(int *flags, QemuOpts *opts)
952 {
953 *flags &= ~BDRV_O_CACHE_MASK;
954
955 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_NO_FLUSH));
956 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
957 *flags |= BDRV_O_NO_FLUSH;
958 }
959
960 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT));
961 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_DIRECT, false)) {
962 *flags |= BDRV_O_NOCACHE;
963 }
964
965 *flags &= ~BDRV_O_RDWR;
966
967 assert(qemu_opt_find(opts, BDRV_OPT_READ_ONLY));
968 if (!qemu_opt_get_bool(opts, BDRV_OPT_READ_ONLY, false)) {
969 *flags |= BDRV_O_RDWR;
970 }
971
972 }
973
974 static void update_options_from_flags(QDict *options, int flags)
975 {
976 if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) {
977 qdict_put(options, BDRV_OPT_CACHE_DIRECT,
978 qbool_from_bool(flags & BDRV_O_NOCACHE));
979 }
980 if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) {
981 qdict_put(options, BDRV_OPT_CACHE_NO_FLUSH,
982 qbool_from_bool(flags & BDRV_O_NO_FLUSH));
983 }
984 if (!qdict_haskey(options, BDRV_OPT_READ_ONLY)) {
985 qdict_put(options, BDRV_OPT_READ_ONLY,
986 qbool_from_bool(!(flags & BDRV_O_RDWR)));
987 }
988 }
989
990 static void bdrv_assign_node_name(BlockDriverState *bs,
991 const char *node_name,
992 Error **errp)
993 {
994 char *gen_node_name = NULL;
995
996 if (!node_name) {
997 node_name = gen_node_name = id_generate(ID_BLOCK);
998 } else if (!id_wellformed(node_name)) {
999 /*
1000 * Check for empty string or invalid characters, but not if it is
1001 * generated (generated names use characters not available to the user)
1002 */
1003 error_setg(errp, "Invalid node name");
1004 return;
1005 }
1006
1007 /* takes care of avoiding namespaces collisions */
1008 if (blk_by_name(node_name)) {
1009 error_setg(errp, "node-name=%s is conflicting with a device id",
1010 node_name);
1011 goto out;
1012 }
1013
1014 /* takes care of avoiding duplicates node names */
1015 if (bdrv_find_node(node_name)) {
1016 error_setg(errp, "Duplicate node name");
1017 goto out;
1018 }
1019
1020 /* copy node name into the bs and insert it into the graph list */
1021 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
1022 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
1023 out:
1024 g_free(gen_node_name);
1025 }
1026
1027 static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv,
1028 const char *node_name, QDict *options,
1029 int open_flags, Error **errp)
1030 {
1031 Error *local_err = NULL;
1032 int ret;
1033
1034 bdrv_assign_node_name(bs, node_name, &local_err);
1035 if (local_err) {
1036 error_propagate(errp, local_err);
1037 return -EINVAL;
1038 }
1039
1040 bs->drv = drv;
1041 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
1042 bs->opaque = g_malloc0(drv->instance_size);
1043
1044 if (drv->bdrv_file_open) {
1045 assert(!drv->bdrv_needs_filename || bs->filename[0]);
1046 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err);
1047 } else if (drv->bdrv_open) {
1048 ret = drv->bdrv_open(bs, options, open_flags, &local_err);
1049 } else {
1050 ret = 0;
1051 }
1052
1053 if (ret < 0) {
1054 if (local_err) {
1055 error_propagate(errp, local_err);
1056 } else if (bs->filename[0]) {
1057 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename);
1058 } else {
1059 error_setg_errno(errp, -ret, "Could not open image");
1060 }
1061 goto free_and_fail;
1062 }
1063
1064 ret = refresh_total_sectors(bs, bs->total_sectors);
1065 if (ret < 0) {
1066 error_setg_errno(errp, -ret, "Could not refresh total sector count");
1067 goto free_and_fail;
1068 }
1069
1070 bdrv_refresh_limits(bs, &local_err);
1071 if (local_err) {
1072 error_propagate(errp, local_err);
1073 ret = -EINVAL;
1074 goto free_and_fail;
1075 }
1076
1077 assert(bdrv_opt_mem_align(bs) != 0);
1078 assert(bdrv_min_mem_align(bs) != 0);
1079 assert(is_power_of_2(bs->bl.request_alignment));
1080
1081 return 0;
1082
1083 free_and_fail:
1084 /* FIXME Close bs first if already opened*/
1085 g_free(bs->opaque);
1086 bs->opaque = NULL;
1087 bs->drv = NULL;
1088 return ret;
1089 }
1090
1091 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
1092 int flags, Error **errp)
1093 {
1094 BlockDriverState *bs;
1095 int ret;
1096
1097 bs = bdrv_new();
1098 bs->open_flags = flags;
1099 bs->explicit_options = qdict_new();
1100 bs->options = qdict_new();
1101 bs->opaque = NULL;
1102
1103 update_options_from_flags(bs->options, flags);
1104
1105 ret = bdrv_open_driver(bs, drv, node_name, bs->options, flags, errp);
1106 if (ret < 0) {
1107 QDECREF(bs->explicit_options);
1108 QDECREF(bs->options);
1109 bdrv_unref(bs);
1110 return NULL;
1111 }
1112
1113 return bs;
1114 }
1115
1116 QemuOptsList bdrv_runtime_opts = {
1117 .name = "bdrv_common",
1118 .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head),
1119 .desc = {
1120 {
1121 .name = "node-name",
1122 .type = QEMU_OPT_STRING,
1123 .help = "Node name of the block device node",
1124 },
1125 {
1126 .name = "driver",
1127 .type = QEMU_OPT_STRING,
1128 .help = "Block driver to use for the node",
1129 },
1130 {
1131 .name = BDRV_OPT_CACHE_DIRECT,
1132 .type = QEMU_OPT_BOOL,
1133 .help = "Bypass software writeback cache on the host",
1134 },
1135 {
1136 .name = BDRV_OPT_CACHE_NO_FLUSH,
1137 .type = QEMU_OPT_BOOL,
1138 .help = "Ignore flush requests",
1139 },
1140 {
1141 .name = BDRV_OPT_READ_ONLY,
1142 .type = QEMU_OPT_BOOL,
1143 .help = "Node is opened in read-only mode",
1144 },
1145 {
1146 .name = "detect-zeroes",
1147 .type = QEMU_OPT_STRING,
1148 .help = "try to optimize zero writes (off, on, unmap)",
1149 },
1150 {
1151 .name = "discard",
1152 .type = QEMU_OPT_STRING,
1153 .help = "discard operation (ignore/off, unmap/on)",
1154 },
1155 { /* end of list */ }
1156 },
1157 };
1158
1159 /*
1160 * Common part for opening disk images and files
1161 *
1162 * Removes all processed options from *options.
1163 */
1164 static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file,
1165 QDict *options, Error **errp)
1166 {
1167 int ret, open_flags;
1168 const char *filename;
1169 const char *driver_name = NULL;
1170 const char *node_name = NULL;
1171 const char *discard;
1172 const char *detect_zeroes;
1173 QemuOpts *opts;
1174 BlockDriver *drv;
1175 Error *local_err = NULL;
1176
1177 assert(bs->file == NULL);
1178 assert(options != NULL && bs->options != options);
1179
1180 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
1181 qemu_opts_absorb_qdict(opts, options, &local_err);
1182 if (local_err) {
1183 error_propagate(errp, local_err);
1184 ret = -EINVAL;
1185 goto fail_opts;
1186 }
1187
1188 update_flags_from_options(&bs->open_flags, opts);
1189
1190 driver_name = qemu_opt_get(opts, "driver");
1191 drv = bdrv_find_format(driver_name);
1192 assert(drv != NULL);
1193
1194 if (file != NULL) {
1195 filename = blk_bs(file)->filename;
1196 } else {
1197 /*
1198 * Caution: while qdict_get_try_str() is fine, getting
1199 * non-string types would require more care. When @options
1200 * come from -blockdev or blockdev_add, its members are typed
1201 * according to the QAPI schema, but when they come from
1202 * -drive, they're all QString.
1203 */
1204 filename = qdict_get_try_str(options, "filename");
1205 }
1206
1207 if (drv->bdrv_needs_filename && !filename) {
1208 error_setg(errp, "The '%s' block driver requires a file name",
1209 drv->format_name);
1210 ret = -EINVAL;
1211 goto fail_opts;
1212 }
1213
1214 trace_bdrv_open_common(bs, filename ?: "", bs->open_flags,
1215 drv->format_name);
1216
1217 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
1218
1219 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
1220 error_setg(errp,
1221 !bs->read_only && bdrv_is_whitelisted(drv, true)
1222 ? "Driver '%s' can only be used for read-only devices"
1223 : "Driver '%s' is not whitelisted",
1224 drv->format_name);
1225 ret = -ENOTSUP;
1226 goto fail_opts;
1227 }
1228
1229 assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */
1230 if (bs->open_flags & BDRV_O_COPY_ON_READ) {
1231 if (!bs->read_only) {
1232 bdrv_enable_copy_on_read(bs);
1233 } else {
1234 error_setg(errp, "Can't use copy-on-read on read-only device");
1235 ret = -EINVAL;
1236 goto fail_opts;
1237 }
1238 }
1239
1240 discard = qemu_opt_get(opts, "discard");
1241 if (discard != NULL) {
1242 if (bdrv_parse_discard_flags(discard, &bs->open_flags) != 0) {
1243 error_setg(errp, "Invalid discard option");
1244 ret = -EINVAL;
1245 goto fail_opts;
1246 }
1247 }
1248
1249 detect_zeroes = qemu_opt_get(opts, "detect-zeroes");
1250 if (detect_zeroes) {
1251 BlockdevDetectZeroesOptions value =
1252 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
1253 detect_zeroes,
1254 BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX,
1255 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
1256 &local_err);
1257 if (local_err) {
1258 error_propagate(errp, local_err);
1259 ret = -EINVAL;
1260 goto fail_opts;
1261 }
1262
1263 if (value == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
1264 !(bs->open_flags & BDRV_O_UNMAP))
1265 {
1266 error_setg(errp, "setting detect-zeroes to unmap is not allowed "
1267 "without setting discard operation to unmap");
1268 ret = -EINVAL;
1269 goto fail_opts;
1270 }
1271
1272 bs->detect_zeroes = value;
1273 }
1274
1275 if (filename != NULL) {
1276 pstrcpy(bs->filename, sizeof(bs->filename), filename);
1277 } else {
1278 bs->filename[0] = '\0';
1279 }
1280 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename);
1281
1282 /* Open the image, either directly or using a protocol */
1283 open_flags = bdrv_open_flags(bs, bs->open_flags);
1284 node_name = qemu_opt_get(opts, "node-name");
1285
1286 assert(!drv->bdrv_file_open || file == NULL);
1287 ret = bdrv_open_driver(bs, drv, node_name, options, open_flags, errp);
1288 if (ret < 0) {
1289 goto fail_opts;
1290 }
1291
1292 qemu_opts_del(opts);
1293 return 0;
1294
1295 fail_opts:
1296 qemu_opts_del(opts);
1297 return ret;
1298 }
1299
1300 static QDict *parse_json_filename(const char *filename, Error **errp)
1301 {
1302 QObject *options_obj;
1303 QDict *options;
1304 int ret;
1305
1306 ret = strstart(filename, "json:", &filename);
1307 assert(ret);
1308
1309 options_obj = qobject_from_json(filename, errp);
1310 if (!options_obj) {
1311 /* Work around qobject_from_json() lossage TODO fix that */
1312 if (errp && !*errp) {
1313 error_setg(errp, "Could not parse the JSON options");
1314 return NULL;
1315 }
1316 error_prepend(errp, "Could not parse the JSON options: ");
1317 return NULL;
1318 }
1319
1320 options = qobject_to_qdict(options_obj);
1321 if (!options) {
1322 qobject_decref(options_obj);
1323 error_setg(errp, "Invalid JSON object given");
1324 return NULL;
1325 }
1326
1327 qdict_flatten(options);
1328
1329 return options;
1330 }
1331
1332 static void parse_json_protocol(QDict *options, const char **pfilename,
1333 Error **errp)
1334 {
1335 QDict *json_options;
1336 Error *local_err = NULL;
1337
1338 /* Parse json: pseudo-protocol */
1339 if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) {
1340 return;
1341 }
1342
1343 json_options = parse_json_filename(*pfilename, &local_err);
1344 if (local_err) {
1345 error_propagate(errp, local_err);
1346 return;
1347 }
1348
1349 /* Options given in the filename have lower priority than options
1350 * specified directly */
1351 qdict_join(options, json_options, false);
1352 QDECREF(json_options);
1353 *pfilename = NULL;
1354 }
1355
1356 /*
1357 * Fills in default options for opening images and converts the legacy
1358 * filename/flags pair to option QDict entries.
1359 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1360 * block driver has been specified explicitly.
1361 */
1362 static int bdrv_fill_options(QDict **options, const char *filename,
1363 int *flags, Error **errp)
1364 {
1365 const char *drvname;
1366 bool protocol = *flags & BDRV_O_PROTOCOL;
1367 bool parse_filename = false;
1368 BlockDriver *drv = NULL;
1369 Error *local_err = NULL;
1370
1371 /*
1372 * Caution: while qdict_get_try_str() is fine, getting non-string
1373 * types would require more care. When @options come from
1374 * -blockdev or blockdev_add, its members are typed according to
1375 * the QAPI schema, but when they come from -drive, they're all
1376 * QString.
1377 */
1378 drvname = qdict_get_try_str(*options, "driver");
1379 if (drvname) {
1380 drv = bdrv_find_format(drvname);
1381 if (!drv) {
1382 error_setg(errp, "Unknown driver '%s'", drvname);
1383 return -ENOENT;
1384 }
1385 /* If the user has explicitly specified the driver, this choice should
1386 * override the BDRV_O_PROTOCOL flag */
1387 protocol = drv->bdrv_file_open;
1388 }
1389
1390 if (protocol) {
1391 *flags |= BDRV_O_PROTOCOL;
1392 } else {
1393 *flags &= ~BDRV_O_PROTOCOL;
1394 }
1395
1396 /* Translate cache options from flags into options */
1397 update_options_from_flags(*options, *flags);
1398
1399 /* Fetch the file name from the options QDict if necessary */
1400 if (protocol && filename) {
1401 if (!qdict_haskey(*options, "filename")) {
1402 qdict_put(*options, "filename", qstring_from_str(filename));
1403 parse_filename = true;
1404 } else {
1405 error_setg(errp, "Can't specify 'file' and 'filename' options at "
1406 "the same time");
1407 return -EINVAL;
1408 }
1409 }
1410
1411 /* Find the right block driver */
1412 /* See cautionary note on accessing @options above */
1413 filename = qdict_get_try_str(*options, "filename");
1414
1415 if (!drvname && protocol) {
1416 if (filename) {
1417 drv = bdrv_find_protocol(filename, parse_filename, errp);
1418 if (!drv) {
1419 return -EINVAL;
1420 }
1421
1422 drvname = drv->format_name;
1423 qdict_put(*options, "driver", qstring_from_str(drvname));
1424 } else {
1425 error_setg(errp, "Must specify either driver or file");
1426 return -EINVAL;
1427 }
1428 }
1429
1430 assert(drv || !protocol);
1431
1432 /* Driver-specific filename parsing */
1433 if (drv && drv->bdrv_parse_filename && parse_filename) {
1434 drv->bdrv_parse_filename(filename, *options, &local_err);
1435 if (local_err) {
1436 error_propagate(errp, local_err);
1437 return -EINVAL;
1438 }
1439
1440 if (!drv->bdrv_needs_filename) {
1441 qdict_del(*options, "filename");
1442 }
1443 }
1444
1445 return 0;
1446 }
1447
1448 static int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
1449 GSList *ignore_children, Error **errp);
1450 static void bdrv_child_abort_perm_update(BdrvChild *c);
1451 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared);
1452
1453 /*
1454 * Check whether permissions on this node can be changed in a way that
1455 * @cumulative_perms and @cumulative_shared_perms are the new cumulative
1456 * permissions of all its parents. This involves checking whether all necessary
1457 * permission changes to child nodes can be performed.
1458 *
1459 * A call to this function must always be followed by a call to bdrv_set_perm()
1460 * or bdrv_abort_perm_update().
1461 */
1462 static int bdrv_check_perm(BlockDriverState *bs, uint64_t cumulative_perms,
1463 uint64_t cumulative_shared_perms,
1464 GSList *ignore_children, Error **errp)
1465 {
1466 BlockDriver *drv = bs->drv;
1467 BdrvChild *c;
1468 int ret;
1469
1470 /* Write permissions never work with read-only images */
1471 if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) &&
1472 bdrv_is_read_only(bs))
1473 {
1474 error_setg(errp, "Block node is read-only");
1475 return -EPERM;
1476 }
1477
1478 /* Check this node */
1479 if (!drv) {
1480 return 0;
1481 }
1482
1483 if (drv->bdrv_check_perm) {
1484 return drv->bdrv_check_perm(bs, cumulative_perms,
1485 cumulative_shared_perms, errp);
1486 }
1487
1488 /* Drivers that never have children can omit .bdrv_child_perm() */
1489 if (!drv->bdrv_child_perm) {
1490 assert(QLIST_EMPTY(&bs->children));
1491 return 0;
1492 }
1493
1494 /* Check all children */
1495 QLIST_FOREACH(c, &bs->children, next) {
1496 uint64_t cur_perm, cur_shared;
1497 drv->bdrv_child_perm(bs, c, c->role,
1498 cumulative_perms, cumulative_shared_perms,
1499 &cur_perm, &cur_shared);
1500 ret = bdrv_child_check_perm(c, cur_perm, cur_shared, ignore_children,
1501 errp);
1502 if (ret < 0) {
1503 return ret;
1504 }
1505 }
1506
1507 return 0;
1508 }
1509
1510 /*
1511 * Notifies drivers that after a previous bdrv_check_perm() call, the
1512 * permission update is not performed and any preparations made for it (e.g.
1513 * taken file locks) need to be undone.
1514 *
1515 * This function recursively notifies all child nodes.
1516 */
1517 static void bdrv_abort_perm_update(BlockDriverState *bs)
1518 {
1519 BlockDriver *drv = bs->drv;
1520 BdrvChild *c;
1521
1522 if (!drv) {
1523 return;
1524 }
1525
1526 if (drv->bdrv_abort_perm_update) {
1527 drv->bdrv_abort_perm_update(bs);
1528 }
1529
1530 QLIST_FOREACH(c, &bs->children, next) {
1531 bdrv_child_abort_perm_update(c);
1532 }
1533 }
1534
1535 static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms,
1536 uint64_t cumulative_shared_perms)
1537 {
1538 BlockDriver *drv = bs->drv;
1539 BdrvChild *c;
1540
1541 if (!drv) {
1542 return;
1543 }
1544
1545 /* Update this node */
1546 if (drv->bdrv_set_perm) {
1547 drv->bdrv_set_perm(bs, cumulative_perms, cumulative_shared_perms);
1548 }
1549
1550 /* Drivers that never have children can omit .bdrv_child_perm() */
1551 if (!drv->bdrv_child_perm) {
1552 assert(QLIST_EMPTY(&bs->children));
1553 return;
1554 }
1555
1556 /* Update all children */
1557 QLIST_FOREACH(c, &bs->children, next) {
1558 uint64_t cur_perm, cur_shared;
1559 drv->bdrv_child_perm(bs, c, c->role,
1560 cumulative_perms, cumulative_shared_perms,
1561 &cur_perm, &cur_shared);
1562 bdrv_child_set_perm(c, cur_perm, cur_shared);
1563 }
1564 }
1565
1566 static void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm,
1567 uint64_t *shared_perm)
1568 {
1569 BdrvChild *c;
1570 uint64_t cumulative_perms = 0;
1571 uint64_t cumulative_shared_perms = BLK_PERM_ALL;
1572
1573 QLIST_FOREACH(c, &bs->parents, next_parent) {
1574 cumulative_perms |= c->perm;
1575 cumulative_shared_perms &= c->shared_perm;
1576 }
1577
1578 *perm = cumulative_perms;
1579 *shared_perm = cumulative_shared_perms;
1580 }
1581
1582 static char *bdrv_child_user_desc(BdrvChild *c)
1583 {
1584 if (c->role->get_parent_desc) {
1585 return c->role->get_parent_desc(c);
1586 }
1587
1588 return g_strdup("another user");
1589 }
1590
1591 static char *bdrv_perm_names(uint64_t perm)
1592 {
1593 struct perm_name {
1594 uint64_t perm;
1595 const char *name;
1596 } permissions[] = {
1597 { BLK_PERM_CONSISTENT_READ, "consistent read" },
1598 { BLK_PERM_WRITE, "write" },
1599 { BLK_PERM_WRITE_UNCHANGED, "write unchanged" },
1600 { BLK_PERM_RESIZE, "resize" },
1601 { BLK_PERM_GRAPH_MOD, "change children" },
1602 { 0, NULL }
1603 };
1604
1605 char *result = g_strdup("");
1606 struct perm_name *p;
1607
1608 for (p = permissions; p->name; p++) {
1609 if (perm & p->perm) {
1610 char *old = result;
1611 result = g_strdup_printf("%s%s%s", old, *old ? ", " : "", p->name);
1612 g_free(old);
1613 }
1614 }
1615
1616 return result;
1617 }
1618
1619 /*
1620 * Checks whether a new reference to @bs can be added if the new user requires
1621 * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is
1622 * set, the BdrvChild objects in this list are ignored in the calculations;
1623 * this allows checking permission updates for an existing reference.
1624 *
1625 * Needs to be followed by a call to either bdrv_set_perm() or
1626 * bdrv_abort_perm_update(). */
1627 static int bdrv_check_update_perm(BlockDriverState *bs, uint64_t new_used_perm,
1628 uint64_t new_shared_perm,
1629 GSList *ignore_children, Error **errp)
1630 {
1631 BdrvChild *c;
1632 uint64_t cumulative_perms = new_used_perm;
1633 uint64_t cumulative_shared_perms = new_shared_perm;
1634
1635 /* There is no reason why anyone couldn't tolerate write_unchanged */
1636 assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED);
1637
1638 QLIST_FOREACH(c, &bs->parents, next_parent) {
1639 if (g_slist_find(ignore_children, c)) {
1640 continue;
1641 }
1642
1643 if ((new_used_perm & c->shared_perm) != new_used_perm) {
1644 char *user = bdrv_child_user_desc(c);
1645 char *perm_names = bdrv_perm_names(new_used_perm & ~c->shared_perm);
1646 error_setg(errp, "Conflicts with use by %s as '%s', which does not "
1647 "allow '%s' on %s",
1648 user, c->name, perm_names, bdrv_get_node_name(c->bs));
1649 g_free(user);
1650 g_free(perm_names);
1651 return -EPERM;
1652 }
1653
1654 if ((c->perm & new_shared_perm) != c->perm) {
1655 char *user = bdrv_child_user_desc(c);
1656 char *perm_names = bdrv_perm_names(c->perm & ~new_shared_perm);
1657 error_setg(errp, "Conflicts with use by %s as '%s', which uses "
1658 "'%s' on %s",
1659 user, c->name, perm_names, bdrv_get_node_name(c->bs));
1660 g_free(user);
1661 g_free(perm_names);
1662 return -EPERM;
1663 }
1664
1665 cumulative_perms |= c->perm;
1666 cumulative_shared_perms &= c->shared_perm;
1667 }
1668
1669 return bdrv_check_perm(bs, cumulative_perms, cumulative_shared_perms,
1670 ignore_children, errp);
1671 }
1672
1673 /* Needs to be followed by a call to either bdrv_child_set_perm() or
1674 * bdrv_child_abort_perm_update(). */
1675 static int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
1676 GSList *ignore_children, Error **errp)
1677 {
1678 int ret;
1679
1680 ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c);
1681 ret = bdrv_check_update_perm(c->bs, perm, shared, ignore_children, errp);
1682 g_slist_free(ignore_children);
1683
1684 return ret;
1685 }
1686
1687 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared)
1688 {
1689 uint64_t cumulative_perms, cumulative_shared_perms;
1690
1691 c->perm = perm;
1692 c->shared_perm = shared;
1693
1694 bdrv_get_cumulative_perm(c->bs, &cumulative_perms,
1695 &cumulative_shared_perms);
1696 bdrv_set_perm(c->bs, cumulative_perms, cumulative_shared_perms);
1697 }
1698
1699 static void bdrv_child_abort_perm_update(BdrvChild *c)
1700 {
1701 bdrv_abort_perm_update(c->bs);
1702 }
1703
1704 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
1705 Error **errp)
1706 {
1707 int ret;
1708
1709 ret = bdrv_child_check_perm(c, perm, shared, NULL, errp);
1710 if (ret < 0) {
1711 bdrv_child_abort_perm_update(c);
1712 return ret;
1713 }
1714
1715 bdrv_child_set_perm(c, perm, shared);
1716
1717 return 0;
1718 }
1719
1720 #define DEFAULT_PERM_PASSTHROUGH (BLK_PERM_CONSISTENT_READ \
1721 | BLK_PERM_WRITE \
1722 | BLK_PERM_WRITE_UNCHANGED \
1723 | BLK_PERM_RESIZE)
1724 #define DEFAULT_PERM_UNCHANGED (BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH)
1725
1726 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
1727 const BdrvChildRole *role,
1728 uint64_t perm, uint64_t shared,
1729 uint64_t *nperm, uint64_t *nshared)
1730 {
1731 if (c == NULL) {
1732 *nperm = perm & DEFAULT_PERM_PASSTHROUGH;
1733 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
1734 return;
1735 }
1736
1737 *nperm = (perm & DEFAULT_PERM_PASSTHROUGH) |
1738 (c->perm & DEFAULT_PERM_UNCHANGED);
1739 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) |
1740 (c->shared_perm & DEFAULT_PERM_UNCHANGED);
1741 }
1742
1743 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
1744 const BdrvChildRole *role,
1745 uint64_t perm, uint64_t shared,
1746 uint64_t *nperm, uint64_t *nshared)
1747 {
1748 bool backing = (role == &child_backing);
1749 assert(role == &child_backing || role == &child_file);
1750
1751 if (!backing) {
1752 /* Apart from the modifications below, the same permissions are
1753 * forwarded and left alone as for filters */
1754 bdrv_filter_default_perms(bs, c, role, perm, shared, &perm, &shared);
1755
1756 /* Format drivers may touch metadata even if the guest doesn't write */
1757 if (!bdrv_is_read_only(bs)) {
1758 perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
1759 }
1760
1761 /* bs->file always needs to be consistent because of the metadata. We
1762 * can never allow other users to resize or write to it. */
1763 perm |= BLK_PERM_CONSISTENT_READ;
1764 shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
1765 } else {
1766 /* We want consistent read from backing files if the parent needs it.
1767 * No other operations are performed on backing files. */
1768 perm &= BLK_PERM_CONSISTENT_READ;
1769
1770 /* If the parent can deal with changing data, we're okay with a
1771 * writable and resizable backing file. */
1772 /* TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? */
1773 if (shared & BLK_PERM_WRITE) {
1774 shared = BLK_PERM_WRITE | BLK_PERM_RESIZE;
1775 } else {
1776 shared = 0;
1777 }
1778
1779 shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD |
1780 BLK_PERM_WRITE_UNCHANGED;
1781 }
1782
1783 *nperm = perm;
1784 *nshared = shared;
1785 }
1786
1787 static void bdrv_replace_child_noperm(BdrvChild *child,
1788 BlockDriverState *new_bs)
1789 {
1790 BlockDriverState *old_bs = child->bs;
1791
1792 if (old_bs && new_bs) {
1793 assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs));
1794 }
1795 if (old_bs) {
1796 if (old_bs->quiesce_counter && child->role->drained_end) {
1797 child->role->drained_end(child);
1798 }
1799 if (child->role->detach) {
1800 child->role->detach(child);
1801 }
1802 QLIST_REMOVE(child, next_parent);
1803 }
1804
1805 child->bs = new_bs;
1806
1807 if (new_bs) {
1808 QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
1809 if (new_bs->quiesce_counter && child->role->drained_begin) {
1810 child->role->drained_begin(child);
1811 }
1812
1813 if (child->role->attach) {
1814 child->role->attach(child);
1815 }
1816 }
1817 }
1818
1819 /*
1820 * Updates @child to change its reference to point to @new_bs, including
1821 * checking and applying the necessary permisson updates both to the old node
1822 * and to @new_bs.
1823 *
1824 * NULL is passed as @new_bs for removing the reference before freeing @child.
1825 *
1826 * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this
1827 * function uses bdrv_set_perm() to update the permissions according to the new
1828 * reference that @new_bs gets.
1829 */
1830 static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
1831 {
1832 BlockDriverState *old_bs = child->bs;
1833 uint64_t perm, shared_perm;
1834
1835 if (old_bs) {
1836 /* Update permissions for old node. This is guaranteed to succeed
1837 * because we're just taking a parent away, so we're loosening
1838 * restrictions. */
1839 bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm);
1840 bdrv_check_perm(old_bs, perm, shared_perm, NULL, &error_abort);
1841 bdrv_set_perm(old_bs, perm, shared_perm);
1842 }
1843
1844 bdrv_replace_child_noperm(child, new_bs);
1845
1846 if (new_bs) {
1847 bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm);
1848 bdrv_set_perm(new_bs, perm, shared_perm);
1849 }
1850 }
1851
1852 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
1853 const char *child_name,
1854 const BdrvChildRole *child_role,
1855 uint64_t perm, uint64_t shared_perm,
1856 void *opaque, Error **errp)
1857 {
1858 BdrvChild *child;
1859 int ret;
1860
1861 ret = bdrv_check_update_perm(child_bs, perm, shared_perm, NULL, errp);
1862 if (ret < 0) {
1863 bdrv_abort_perm_update(child_bs);
1864 return NULL;
1865 }
1866
1867 child = g_new(BdrvChild, 1);
1868 *child = (BdrvChild) {
1869 .bs = NULL,
1870 .name = g_strdup(child_name),
1871 .role = child_role,
1872 .perm = perm,
1873 .shared_perm = shared_perm,
1874 .opaque = opaque,
1875 };
1876
1877 /* This performs the matching bdrv_set_perm() for the above check. */
1878 bdrv_replace_child(child, child_bs);
1879
1880 return child;
1881 }
1882
1883 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
1884 BlockDriverState *child_bs,
1885 const char *child_name,
1886 const BdrvChildRole *child_role,
1887 Error **errp)
1888 {
1889 BdrvChild *child;
1890 uint64_t perm, shared_perm;
1891
1892 bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm);
1893
1894 assert(parent_bs->drv);
1895 assert(bdrv_get_aio_context(parent_bs) == bdrv_get_aio_context(child_bs));
1896 parent_bs->drv->bdrv_child_perm(parent_bs, NULL, child_role,
1897 perm, shared_perm, &perm, &shared_perm);
1898
1899 child = bdrv_root_attach_child(child_bs, child_name, child_role,
1900 perm, shared_perm, parent_bs, errp);
1901 if (child == NULL) {
1902 return NULL;
1903 }
1904
1905 QLIST_INSERT_HEAD(&parent_bs->children, child, next);
1906 return child;
1907 }
1908
1909 static void bdrv_detach_child(BdrvChild *child)
1910 {
1911 if (child->next.le_prev) {
1912 QLIST_REMOVE(child, next);
1913 child->next.le_prev = NULL;
1914 }
1915
1916 bdrv_replace_child(child, NULL);
1917
1918 g_free(child->name);
1919 g_free(child);
1920 }
1921
1922 void bdrv_root_unref_child(BdrvChild *child)
1923 {
1924 BlockDriverState *child_bs;
1925
1926 child_bs = child->bs;
1927 bdrv_detach_child(child);
1928 bdrv_unref(child_bs);
1929 }
1930
1931 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child)
1932 {
1933 if (child == NULL) {
1934 return;
1935 }
1936
1937 if (child->bs->inherits_from == parent) {
1938 BdrvChild *c;
1939
1940 /* Remove inherits_from only when the last reference between parent and
1941 * child->bs goes away. */
1942 QLIST_FOREACH(c, &parent->children, next) {
1943 if (c != child && c->bs == child->bs) {
1944 break;
1945 }
1946 }
1947 if (c == NULL) {
1948 child->bs->inherits_from = NULL;
1949 }
1950 }
1951
1952 bdrv_root_unref_child(child);
1953 }
1954
1955
1956 static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load)
1957 {
1958 BdrvChild *c;
1959 QLIST_FOREACH(c, &bs->parents, next_parent) {
1960 if (c->role->change_media) {
1961 c->role->change_media(c, load);
1962 }
1963 }
1964 }
1965
1966 static void bdrv_parent_cb_resize(BlockDriverState *bs)
1967 {
1968 BdrvChild *c;
1969 QLIST_FOREACH(c, &bs->parents, next_parent) {
1970 if (c->role->resize) {
1971 c->role->resize(c);
1972 }
1973 }
1974 }
1975
1976 /*
1977 * Sets the backing file link of a BDS. A new reference is created; callers
1978 * which don't need their own reference any more must call bdrv_unref().
1979 */
1980 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
1981 Error **errp)
1982 {
1983 if (backing_hd) {
1984 bdrv_ref(backing_hd);
1985 }
1986
1987 if (bs->backing) {
1988 bdrv_unref_child(bs, bs->backing);
1989 }
1990
1991 if (!backing_hd) {
1992 bs->backing = NULL;
1993 goto out;
1994 }
1995
1996 bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing,
1997 errp);
1998 if (!bs->backing) {
1999 bdrv_unref(backing_hd);
2000 }
2001
2002 bdrv_refresh_filename(bs);
2003
2004 out:
2005 bdrv_refresh_limits(bs, NULL);
2006 }
2007
2008 /*
2009 * Opens the backing file for a BlockDriverState if not yet open
2010 *
2011 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
2012 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2013 * itself, all options starting with "${bdref_key}." are considered part of the
2014 * BlockdevRef.
2015 *
2016 * TODO Can this be unified with bdrv_open_image()?
2017 */
2018 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
2019 const char *bdref_key, Error **errp)
2020 {
2021 char *backing_filename = g_malloc0(PATH_MAX);
2022 char *bdref_key_dot;
2023 const char *reference = NULL;
2024 int ret = 0;
2025 BlockDriverState *backing_hd;
2026 QDict *options;
2027 QDict *tmp_parent_options = NULL;
2028 Error *local_err = NULL;
2029
2030 if (bs->backing != NULL) {
2031 goto free_exit;
2032 }
2033
2034 /* NULL means an empty set of options */
2035 if (parent_options == NULL) {
2036 tmp_parent_options = qdict_new();
2037 parent_options = tmp_parent_options;
2038 }
2039
2040 bs->open_flags &= ~BDRV_O_NO_BACKING;
2041
2042 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
2043 qdict_extract_subqdict(parent_options, &options, bdref_key_dot);
2044 g_free(bdref_key_dot);
2045
2046 /*
2047 * Caution: while qdict_get_try_str() is fine, getting non-string
2048 * types would require more care. When @parent_options come from
2049 * -blockdev or blockdev_add, its members are typed according to
2050 * the QAPI schema, but when they come from -drive, they're all
2051 * QString.
2052 */
2053 reference = qdict_get_try_str(parent_options, bdref_key);
2054 if (reference || qdict_haskey(options, "file.filename")) {
2055 backing_filename[0] = '\0';
2056 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
2057 QDECREF(options);
2058 goto free_exit;
2059 } else {
2060 bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX,
2061 &local_err);
2062 if (local_err) {
2063 ret = -EINVAL;
2064 error_propagate(errp, local_err);
2065 QDECREF(options);
2066 goto free_exit;
2067 }
2068 }
2069
2070 if (!bs->drv || !bs->drv->supports_backing) {
2071 ret = -EINVAL;
2072 error_setg(errp, "Driver doesn't support backing files");
2073 QDECREF(options);
2074 goto free_exit;
2075 }
2076
2077 if (bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) {
2078 qdict_put(options, "driver", qstring_from_str(bs->backing_format));
2079 }
2080
2081 backing_hd = bdrv_open_inherit(*backing_filename ? backing_filename : NULL,
2082 reference, options, 0, bs, &child_backing,
2083 errp);
2084 if (!backing_hd) {
2085 bs->open_flags |= BDRV_O_NO_BACKING;
2086 error_prepend(errp, "Could not open backing file: ");
2087 ret = -EINVAL;
2088 goto free_exit;
2089 }
2090
2091 /* Hook up the backing file link; drop our reference, bs owns the
2092 * backing_hd reference now */
2093 bdrv_set_backing_hd(bs, backing_hd, &local_err);
2094 bdrv_unref(backing_hd);
2095 if (local_err) {
2096 error_propagate(errp, local_err);
2097 ret = -EINVAL;
2098 goto free_exit;
2099 }
2100
2101 qdict_del(parent_options, bdref_key);
2102
2103 free_exit:
2104 g_free(backing_filename);
2105 QDECREF(tmp_parent_options);
2106 return ret;
2107 }
2108
2109 static BlockDriverState *
2110 bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
2111 BlockDriverState *parent, const BdrvChildRole *child_role,
2112 bool allow_none, Error **errp)
2113 {
2114 BlockDriverState *bs = NULL;
2115 QDict *image_options;
2116 char *bdref_key_dot;
2117 const char *reference;
2118
2119 assert(child_role != NULL);
2120
2121 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
2122 qdict_extract_subqdict(options, &image_options, bdref_key_dot);
2123 g_free(bdref_key_dot);
2124
2125 /*
2126 * Caution: while qdict_get_try_str() is fine, getting non-string
2127 * types would require more care. When @options come from
2128 * -blockdev or blockdev_add, its members are typed according to
2129 * the QAPI schema, but when they come from -drive, they're all
2130 * QString.
2131 */
2132 reference = qdict_get_try_str(options, bdref_key);
2133 if (!filename && !reference && !qdict_size(image_options)) {
2134 if (!allow_none) {
2135 error_setg(errp, "A block device must be specified for \"%s\"",
2136 bdref_key);
2137 }
2138 QDECREF(image_options);
2139 goto done;
2140 }
2141
2142 bs = bdrv_open_inherit(filename, reference, image_options, 0,
2143 parent, child_role, errp);
2144 if (!bs) {
2145 goto done;
2146 }
2147
2148 done:
2149 qdict_del(options, bdref_key);
2150 return bs;
2151 }
2152
2153 /*
2154 * Opens a disk image whose options are given as BlockdevRef in another block
2155 * device's options.
2156 *
2157 * If allow_none is true, no image will be opened if filename is false and no
2158 * BlockdevRef is given. NULL will be returned, but errp remains unset.
2159 *
2160 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
2161 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2162 * itself, all options starting with "${bdref_key}." are considered part of the
2163 * BlockdevRef.
2164 *
2165 * The BlockdevRef will be removed from the options QDict.
2166 */
2167 BdrvChild *bdrv_open_child(const char *filename,
2168 QDict *options, const char *bdref_key,
2169 BlockDriverState *parent,
2170 const BdrvChildRole *child_role,
2171 bool allow_none, Error **errp)
2172 {
2173 BdrvChild *c;
2174 BlockDriverState *bs;
2175
2176 bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_role,
2177 allow_none, errp);
2178 if (bs == NULL) {
2179 return NULL;
2180 }
2181
2182 c = bdrv_attach_child(parent, bs, bdref_key, child_role, errp);
2183 if (!c) {
2184 bdrv_unref(bs);
2185 return NULL;
2186 }
2187
2188 return c;
2189 }
2190
2191 static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
2192 int flags,
2193 QDict *snapshot_options,
2194 Error **errp)
2195 {
2196 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
2197 char *tmp_filename = g_malloc0(PATH_MAX + 1);
2198 int64_t total_size;
2199 QemuOpts *opts = NULL;
2200 BlockDriverState *bs_snapshot;
2201 Error *local_err = NULL;
2202 int ret;
2203
2204 /* if snapshot, we create a temporary backing file and open it
2205 instead of opening 'filename' directly */
2206
2207 /* Get the required size from the image */
2208 total_size = bdrv_getlength(bs);
2209 if (total_size < 0) {
2210 error_setg_errno(errp, -total_size, "Could not get image size");
2211 goto out;
2212 }
2213
2214 /* Create the temporary image */
2215 ret = get_tmp_filename(tmp_filename, PATH_MAX + 1);
2216 if (ret < 0) {
2217 error_setg_errno(errp, -ret, "Could not get temporary filename");
2218 goto out;
2219 }
2220
2221 opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0,
2222 &error_abort);
2223 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort);
2224 ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp);
2225 qemu_opts_del(opts);
2226 if (ret < 0) {
2227 error_prepend(errp, "Could not create temporary overlay '%s': ",
2228 tmp_filename);
2229 goto out;
2230 }
2231
2232 /* Prepare options QDict for the temporary file */
2233 qdict_put(snapshot_options, "file.driver",
2234 qstring_from_str("file"));
2235 qdict_put(snapshot_options, "file.filename",
2236 qstring_from_str(tmp_filename));
2237 qdict_put(snapshot_options, "driver",
2238 qstring_from_str("qcow2"));
2239
2240 bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp);
2241 snapshot_options = NULL;
2242 if (!bs_snapshot) {
2243 ret = -EINVAL;
2244 goto out;
2245 }
2246
2247 /* bdrv_append() consumes a strong reference to bs_snapshot (i.e. it will
2248 * call bdrv_unref() on it), so in order to be able to return one, we have
2249 * to increase bs_snapshot's refcount here */
2250 bdrv_ref(bs_snapshot);
2251 bdrv_append(bs_snapshot, bs, &local_err);
2252 if (local_err) {
2253 error_propagate(errp, local_err);
2254 ret = -EINVAL;
2255 goto out;
2256 }
2257
2258 g_free(tmp_filename);
2259 return bs_snapshot;
2260
2261 out:
2262 QDECREF(snapshot_options);
2263 g_free(tmp_filename);
2264 return NULL;
2265 }
2266
2267 /*
2268 * Opens a disk image (raw, qcow2, vmdk, ...)
2269 *
2270 * options is a QDict of options to pass to the block drivers, or NULL for an
2271 * empty set of options. The reference to the QDict belongs to the block layer
2272 * after the call (even on failure), so if the caller intends to reuse the
2273 * dictionary, it needs to use QINCREF() before calling bdrv_open.
2274 *
2275 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
2276 * If it is not NULL, the referenced BDS will be reused.
2277 *
2278 * The reference parameter may be used to specify an existing block device which
2279 * should be opened. If specified, neither options nor a filename may be given,
2280 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
2281 */
2282 static BlockDriverState *bdrv_open_inherit(const char *filename,
2283 const char *reference,
2284 QDict *options, int flags,
2285 BlockDriverState *parent,
2286 const BdrvChildRole *child_role,
2287 Error **errp)
2288 {
2289 int ret;
2290 BlockBackend *file = NULL;
2291 BlockDriverState *bs;
2292 BlockDriver *drv = NULL;
2293 const char *drvname;
2294 const char *backing;
2295 Error *local_err = NULL;
2296 QDict *snapshot_options = NULL;
2297 int snapshot_flags = 0;
2298
2299 assert(!child_role || !flags);
2300 assert(!child_role == !parent);
2301
2302 if (reference) {
2303 bool options_non_empty = options ? qdict_size(options) : false;
2304 QDECREF(options);
2305
2306 if (filename || options_non_empty) {
2307 error_setg(errp, "Cannot reference an existing block device with "
2308 "additional options or a new filename");
2309 return NULL;
2310 }
2311
2312 bs = bdrv_lookup_bs(reference, reference, errp);
2313 if (!bs) {
2314 return NULL;
2315 }
2316
2317 bdrv_ref(bs);
2318 return bs;
2319 }
2320
2321 bs = bdrv_new();
2322
2323 /* NULL means an empty set of options */
2324 if (options == NULL) {
2325 options = qdict_new();
2326 }
2327
2328 /* json: syntax counts as explicit options, as if in the QDict */
2329 parse_json_protocol(options, &filename, &local_err);
2330 if (local_err) {
2331 goto fail;
2332 }
2333
2334 bs->explicit_options = qdict_clone_shallow(options);
2335
2336 if (child_role) {
2337 bs->inherits_from = parent;
2338 child_role->inherit_options(&flags, options,
2339 parent->open_flags, parent->options);
2340 }
2341
2342 ret = bdrv_fill_options(&options, filename, &flags, &local_err);
2343 if (local_err) {
2344 goto fail;
2345 }
2346
2347 /*
2348 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
2349 * Caution: getting a boolean member of @options requires care.
2350 * When @options come from -blockdev or blockdev_add, members are
2351 * typed according to the QAPI schema, but when they come from
2352 * -drive, they're all QString.
2353 */
2354 if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") &&
2355 !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) {
2356 flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR);
2357 } else {
2358 flags &= ~BDRV_O_RDWR;
2359 }
2360
2361 if (flags & BDRV_O_SNAPSHOT) {
2362 snapshot_options = qdict_new();
2363 bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options,
2364 flags, options);
2365 /* Let bdrv_backing_options() override "read-only" */
2366 qdict_del(options, BDRV_OPT_READ_ONLY);
2367 bdrv_backing_options(&flags, options, flags, options);
2368 }
2369
2370 bs->open_flags = flags;
2371 bs->options = options;
2372 options = qdict_clone_shallow(options);
2373
2374 /* Find the right image format driver */
2375 /* See cautionary note on accessing @options above */
2376 drvname = qdict_get_try_str(options, "driver");
2377 if (drvname) {
2378 drv = bdrv_find_format(drvname);
2379 if (!drv) {
2380 error_setg(errp, "Unknown driver: '%s'", drvname);
2381 goto fail;
2382 }
2383 }
2384
2385 assert(drvname || !(flags & BDRV_O_PROTOCOL));
2386
2387 /* See cautionary note on accessing @options above */
2388 backing = qdict_get_try_str(options, "backing");
2389 if (backing && *backing == '\0') {
2390 flags |= BDRV_O_NO_BACKING;
2391 qdict_del(options, "backing");
2392 }
2393
2394 /* Open image file without format layer. This BlockBackend is only used for
2395 * probing, the block drivers will do their own bdrv_open_child() for the
2396 * same BDS, which is why we put the node name back into options. */
2397 if ((flags & BDRV_O_PROTOCOL) == 0) {
2398 BlockDriverState *file_bs;
2399
2400 file_bs = bdrv_open_child_bs(filename, options, "file", bs,
2401 &child_file, true, &local_err);
2402 if (local_err) {
2403 goto fail;
2404 }
2405 if (file_bs != NULL) {
2406 file = blk_new(BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
2407 blk_insert_bs(file, file_bs, &local_err);
2408 bdrv_unref(file_bs);
2409 if (local_err) {
2410 goto fail;
2411 }
2412
2413 qdict_put(options, "file",
2414 qstring_from_str(bdrv_get_node_name(file_bs)));
2415 }
2416 }
2417
2418 /* Image format probing */
2419 bs->probed = !drv;
2420 if (!drv && file) {
2421 ret = find_image_format(file, filename, &drv, &local_err);
2422 if (ret < 0) {
2423 goto fail;
2424 }
2425 /*
2426 * This option update would logically belong in bdrv_fill_options(),
2427 * but we first need to open bs->file for the probing to work, while
2428 * opening bs->file already requires the (mostly) final set of options
2429 * so that cache mode etc. can be inherited.
2430 *
2431 * Adding the driver later is somewhat ugly, but it's not an option
2432 * that would ever be inherited, so it's correct. We just need to make
2433 * sure to update both bs->options (which has the full effective
2434 * options for bs) and options (which has file.* already removed).
2435 */
2436 qdict_put(bs->options, "driver", qstring_from_str(drv->format_name));
2437 qdict_put(options, "driver", qstring_from_str(drv->format_name));
2438 } else if (!drv) {
2439 error_setg(errp, "Must specify either driver or file");
2440 goto fail;
2441 }
2442
2443 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
2444 assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open);
2445 /* file must be NULL if a protocol BDS is about to be created
2446 * (the inverse results in an error message from bdrv_open_common()) */
2447 assert(!(flags & BDRV_O_PROTOCOL) || !file);
2448
2449 /* Open the image */
2450 ret = bdrv_open_common(bs, file, options, &local_err);
2451 if (ret < 0) {
2452 goto fail;
2453 }
2454
2455 if (file) {
2456 blk_unref(file);
2457 file = NULL;
2458 }
2459
2460 /* If there is a backing file, use it */
2461 if ((flags & BDRV_O_NO_BACKING) == 0) {
2462 ret = bdrv_open_backing_file(bs, options, "backing", &local_err);
2463 if (ret < 0) {
2464 goto close_and_fail;
2465 }
2466 }
2467
2468 bdrv_refresh_filename(bs);
2469
2470 /* Check if any unknown options were used */
2471 if (qdict_size(options) != 0) {
2472 const QDictEntry *entry = qdict_first(options);
2473 if (flags & BDRV_O_PROTOCOL) {
2474 error_setg(errp, "Block protocol '%s' doesn't support the option "
2475 "'%s'", drv->format_name, entry->key);
2476 } else {
2477 error_setg(errp,
2478 "Block format '%s' does not support the option '%s'",
2479 drv->format_name, entry->key);
2480 }
2481
2482 goto close_and_fail;
2483 }
2484
2485 if (!bdrv_key_required(bs)) {
2486 bdrv_parent_cb_change_media(bs, true);
2487 } else if (!runstate_check(RUN_STATE_PRELAUNCH)
2488 && !runstate_check(RUN_STATE_INMIGRATE)
2489 && !runstate_check(RUN_STATE_PAUSED)) { /* HACK */
2490 error_setg(errp,
2491 "Guest must be stopped for opening of encrypted image");
2492 goto close_and_fail;
2493 }
2494
2495 QDECREF(options);
2496
2497 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
2498 * temporary snapshot afterwards. */
2499 if (snapshot_flags) {
2500 BlockDriverState *snapshot_bs;
2501 snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags,
2502 snapshot_options, &local_err);
2503 snapshot_options = NULL;
2504 if (local_err) {
2505 goto close_and_fail;
2506 }
2507 /* We are not going to return bs but the overlay on top of it
2508 * (snapshot_bs); thus, we have to drop the strong reference to bs
2509 * (which we obtained by calling bdrv_new()). bs will not be deleted,
2510 * though, because the overlay still has a reference to it. */
2511 bdrv_unref(bs);
2512 bs = snapshot_bs;
2513 }
2514
2515 return bs;
2516
2517 fail:
2518 blk_unref(file);
2519 if (bs->file != NULL) {
2520 bdrv_unref_child(bs, bs->file);
2521 }
2522 QDECREF(snapshot_options);
2523 QDECREF(bs->explicit_options);
2524 QDECREF(bs->options);
2525 QDECREF(options);
2526 bs->options = NULL;
2527 bdrv_unref(bs);
2528 error_propagate(errp, local_err);
2529 return NULL;
2530
2531 close_and_fail:
2532 bdrv_unref(bs);
2533 QDECREF(snapshot_options);
2534 QDECREF(options);
2535 error_propagate(errp, local_err);
2536 return NULL;
2537 }
2538
2539 BlockDriverState *bdrv_open(const char *filename, const char *reference,
2540 QDict *options, int flags, Error **errp)
2541 {
2542 return bdrv_open_inherit(filename, reference, options, flags, NULL,
2543 NULL, errp);
2544 }
2545
2546 typedef struct BlockReopenQueueEntry {
2547 bool prepared;
2548 BDRVReopenState state;
2549 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry;
2550 } BlockReopenQueueEntry;
2551
2552 /*
2553 * Adds a BlockDriverState to a simple queue for an atomic, transactional
2554 * reopen of multiple devices.
2555 *
2556 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT
2557 * already performed, or alternatively may be NULL a new BlockReopenQueue will
2558 * be created and initialized. This newly created BlockReopenQueue should be
2559 * passed back in for subsequent calls that are intended to be of the same
2560 * atomic 'set'.
2561 *
2562 * bs is the BlockDriverState to add to the reopen queue.
2563 *
2564 * options contains the changed options for the associated bs
2565 * (the BlockReopenQueue takes ownership)
2566 *
2567 * flags contains the open flags for the associated bs
2568 *
2569 * returns a pointer to bs_queue, which is either the newly allocated
2570 * bs_queue, or the existing bs_queue being used.
2571 *
2572 */
2573 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
2574 BlockDriverState *bs,
2575 QDict *options,
2576 int flags,
2577 const BdrvChildRole *role,
2578 QDict *parent_options,
2579 int parent_flags)
2580 {
2581 assert(bs != NULL);
2582
2583 BlockReopenQueueEntry *bs_entry;
2584 BdrvChild *child;
2585 QDict *old_options, *explicit_options;
2586
2587 if (bs_queue == NULL) {
2588 bs_queue = g_new0(BlockReopenQueue, 1);
2589 QSIMPLEQ_INIT(bs_queue);
2590 }
2591
2592 if (!options) {
2593 options = qdict_new();
2594 }
2595
2596 /* Check if this BlockDriverState is already in the queue */
2597 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
2598 if (bs == bs_entry->state.bs) {
2599 break;
2600 }
2601 }
2602
2603 /*
2604 * Precedence of options:
2605 * 1. Explicitly passed in options (highest)
2606 * 2. Set in flags (only for top level)
2607 * 3. Retained from explicitly set options of bs
2608 * 4. Inherited from parent node
2609 * 5. Retained from effective options of bs
2610 */
2611
2612 if (!parent_options) {
2613 /*
2614 * Any setting represented by flags is always updated. If the
2615 * corresponding QDict option is set, it takes precedence. Otherwise
2616 * the flag is translated into a QDict option. The old setting of bs is
2617 * not considered.
2618 */
2619 update_options_from_flags(options, flags);
2620 }
2621
2622 /* Old explicitly set values (don't overwrite by inherited value) */
2623 if (bs_entry) {
2624 old_options = qdict_clone_shallow(bs_entry->state.explicit_options);
2625 } else {
2626 old_options = qdict_clone_shallow(bs->explicit_options);
2627 }
2628 bdrv_join_options(bs, options, old_options);
2629 QDECREF(old_options);
2630
2631 explicit_options = qdict_clone_shallow(options);
2632
2633 /* Inherit from parent node */
2634 if (parent_options) {
2635 assert(!flags);
2636 role->inherit_options(&flags, options, parent_flags, parent_options);
2637 }
2638
2639 /* Old values are used for options that aren't set yet */
2640 old_options = qdict_clone_shallow(bs->options);
2641 bdrv_join_options(bs, options, old_options);
2642 QDECREF(old_options);
2643
2644 /* bdrv_open() masks this flag out */
2645 flags &= ~BDRV_O_PROTOCOL;
2646
2647 QLIST_FOREACH(child, &bs->children, next) {
2648 QDict *new_child_options;
2649 char *child_key_dot;
2650
2651 /* reopen can only change the options of block devices that were
2652 * implicitly created and inherited options. For other (referenced)
2653 * block devices, a syntax like "backing.foo" results in an error. */
2654 if (child->bs->inherits_from != bs) {
2655 continue;
2656 }
2657
2658 child_key_dot = g_strdup_printf("%s.", child->name);
2659 qdict_extract_subqdict(options, &new_child_options, child_key_dot);
2660 g_free(child_key_dot);
2661
2662 bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options, 0,
2663 child->role, options, flags);
2664 }
2665
2666 if (!bs_entry) {
2667 bs_entry = g_new0(BlockReopenQueueEntry, 1);
2668 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry);
2669 } else {
2670 QDECREF(bs_entry->state.options);
2671 QDECREF(bs_entry->state.explicit_options);
2672 }
2673
2674 bs_entry->state.bs = bs;
2675 bs_entry->state.options = options;
2676 bs_entry->state.explicit_options = explicit_options;
2677 bs_entry->state.flags = flags;
2678
2679 return bs_queue;
2680 }
2681
2682 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
2683 BlockDriverState *bs,
2684 QDict *options, int flags)
2685 {
2686 return bdrv_reopen_queue_child(bs_queue, bs, options, flags,
2687 NULL, NULL, 0);
2688 }
2689
2690 /*
2691 * Reopen multiple BlockDriverStates atomically & transactionally.
2692 *
2693 * The queue passed in (bs_queue) must have been built up previous
2694 * via bdrv_reopen_queue().
2695 *
2696 * Reopens all BDS specified in the queue, with the appropriate
2697 * flags. All devices are prepared for reopen, and failure of any
2698 * device will cause all device changes to be abandonded, and intermediate
2699 * data cleaned up.
2700 *
2701 * If all devices prepare successfully, then the changes are committed
2702 * to all devices.
2703 *
2704 */
2705 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp)
2706 {
2707 int ret = -1;
2708 BlockReopenQueueEntry *bs_entry, *next;
2709 Error *local_err = NULL;
2710
2711 assert(bs_queue != NULL);
2712
2713 aio_context_release(ctx);
2714 bdrv_drain_all_begin();
2715 aio_context_acquire(ctx);
2716
2717 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
2718 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) {
2719 error_propagate(errp, local_err);
2720 goto cleanup;
2721 }
2722 bs_entry->prepared = true;
2723 }
2724
2725 /* If we reach this point, we have success and just need to apply the
2726 * changes
2727 */
2728 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
2729 bdrv_reopen_commit(&bs_entry->state);
2730 }
2731
2732 ret = 0;
2733
2734 cleanup:
2735 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
2736 if (ret && bs_entry->prepared) {
2737 bdrv_reopen_abort(&bs_entry->state);
2738 } else if (ret) {
2739 QDECREF(bs_entry->state.explicit_options);
2740 }
2741 QDECREF(bs_entry->state.options);
2742 g_free(bs_entry);
2743 }
2744 g_free(bs_queue);
2745
2746 bdrv_drain_all_end();
2747
2748 return ret;
2749 }
2750
2751
2752 /* Reopen a single BlockDriverState with the specified flags. */
2753 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp)
2754 {
2755 int ret = -1;
2756 Error *local_err = NULL;
2757 BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags);
2758
2759 ret = bdrv_reopen_multiple(bdrv_get_aio_context(bs), queue, &local_err);
2760 if (local_err != NULL) {
2761 error_propagate(errp, local_err);
2762 }
2763 return ret;
2764 }
2765
2766
2767 /*
2768 * Prepares a BlockDriverState for reopen. All changes are staged in the
2769 * 'opaque' field of the BDRVReopenState, which is used and allocated by
2770 * the block driver layer .bdrv_reopen_prepare()
2771 *
2772 * bs is the BlockDriverState to reopen
2773 * flags are the new open flags
2774 * queue is the reopen queue
2775 *
2776 * Returns 0 on success, non-zero on error. On error errp will be set
2777 * as well.
2778 *
2779 * On failure, bdrv_reopen_abort() will be called to clean up any data.
2780 * It is the responsibility of the caller to then call the abort() or
2781 * commit() for any other BDS that have been left in a prepare() state
2782 *
2783 */
2784 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
2785 Error **errp)
2786 {
2787 int ret = -1;
2788 Error *local_err = NULL;
2789 BlockDriver *drv;
2790 QemuOpts *opts;
2791 const char *value;
2792 bool read_only;
2793
2794 assert(reopen_state != NULL);
2795 assert(reopen_state->bs->drv != NULL);
2796 drv = reopen_state->bs->drv;
2797
2798 /* Process generic block layer options */
2799 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
2800 qemu_opts_absorb_qdict(opts, reopen_state->options, &local_err);
2801 if (local_err) {
2802 error_propagate(errp, local_err);
2803 ret = -EINVAL;
2804 goto error;
2805 }
2806
2807 update_flags_from_options(&reopen_state->flags, opts);
2808
2809 /* node-name and driver must be unchanged. Put them back into the QDict, so
2810 * that they are checked at the end of this function. */
2811 value = qemu_opt_get(opts, "node-name");
2812 if (value) {
2813 qdict_put(reopen_state->options, "node-name", qstring_from_str(value));
2814 }
2815
2816 value = qemu_opt_get(opts, "driver");
2817 if (value) {
2818 qdict_put(reopen_state->options, "driver", qstring_from_str(value));
2819 }
2820
2821 /* If we are to stay read-only, do not allow permission change
2822 * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is
2823 * not set, or if the BDS still has copy_on_read enabled */
2824 read_only = !(reopen_state->flags & BDRV_O_RDWR);
2825 ret = bdrv_can_set_read_only(reopen_state->bs, read_only, &local_err);
2826 if (local_err) {
2827 error_propagate(errp, local_err);
2828 goto error;
2829 }
2830
2831
2832 ret = bdrv_flush(reopen_state->bs);
2833 if (ret) {
2834 error_setg_errno(errp, -ret, "Error flushing drive");
2835 goto error;
2836 }
2837
2838 if (drv->bdrv_reopen_prepare) {
2839 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err);
2840 if (ret) {
2841 if (local_err != NULL) {
2842 error_propagate(errp, local_err);
2843 } else {
2844 error_setg(errp, "failed while preparing to reopen image '%s'",
2845 reopen_state->bs->filename);
2846 }
2847 goto error;
2848 }
2849 } else {
2850 /* It is currently mandatory to have a bdrv_reopen_prepare()
2851 * handler for each supported drv. */
2852 error_setg(errp, "Block format '%s' used by node '%s' "
2853 "does not support reopening files", drv->format_name,
2854 bdrv_get_device_or_node_name(reopen_state->bs));
2855 ret = -1;
2856 goto error;
2857 }
2858
2859 /* Options that are not handled are only okay if they are unchanged
2860 * compared to the old state. It is expected that some options are only
2861 * used for the initial open, but not reopen (e.g. filename) */
2862 if (qdict_size(reopen_state->options)) {
2863 const QDictEntry *entry = qdict_first(reopen_state->options);
2864
2865 do {
2866 QString *new_obj = qobject_to_qstring(entry->value);
2867 const char *new = qstring_get_str(new_obj);
2868 /*
2869 * Caution: while qdict_get_try_str() is fine, getting
2870 * non-string types would require more care. When
2871 * bs->options come from -blockdev or blockdev_add, its
2872 * members are typed according to the QAPI schema, but
2873 * when they come from -drive, they're all QString.
2874 */
2875 const char *old = qdict_get_try_str(reopen_state->bs->options,
2876 entry->key);
2877
2878 if (!old || strcmp(new, old)) {
2879 error_setg(errp, "Cannot change the option '%s'", entry->key);
2880 ret = -EINVAL;
2881 goto error;
2882 }
2883 } while ((entry = qdict_next(reopen_state->options, entry)));
2884 }
2885
2886 ret = 0;
2887
2888 error:
2889 qemu_opts_del(opts);
2890 return ret;
2891 }
2892
2893 /*
2894 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
2895 * makes them final by swapping the staging BlockDriverState contents into
2896 * the active BlockDriverState contents.
2897 */
2898 void bdrv_reopen_commit(BDRVReopenState *reopen_state)
2899 {
2900 BlockDriver *drv;
2901
2902 assert(reopen_state != NULL);
2903 drv = reopen_state->bs->drv;
2904 assert(drv != NULL);
2905
2906 /* If there are any driver level actions to take */
2907 if (drv->bdrv_reopen_commit) {
2908 drv->bdrv_reopen_commit(reopen_state);
2909 }
2910
2911 /* set BDS specific flags now */
2912 QDECREF(reopen_state->bs->explicit_options);
2913
2914 reopen_state->bs->explicit_options = reopen_state->explicit_options;
2915 reopen_state->bs->open_flags = reopen_state->flags;
2916 reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
2917
2918 bdrv_refresh_limits(reopen_state->bs, NULL);
2919 }
2920
2921 /*
2922 * Abort the reopen, and delete and free the staged changes in
2923 * reopen_state
2924 */
2925 void bdrv_reopen_abort(BDRVReopenState *reopen_state)
2926 {
2927 BlockDriver *drv;
2928
2929 assert(reopen_state != NULL);
2930 drv = reopen_state->bs->drv;
2931 assert(drv != NULL);
2932
2933 if (drv->bdrv_reopen_abort) {
2934 drv->bdrv_reopen_abort(reopen_state);
2935 }
2936
2937 QDECREF(reopen_state->explicit_options);
2938 }
2939
2940
2941 static void bdrv_close(BlockDriverState *bs)
2942 {
2943 BdrvAioNotifier *ban, *ban_next;
2944
2945 assert(!bs->job);
2946 assert(!bs->refcnt);
2947
2948 bdrv_drained_begin(bs); /* complete I/O */
2949 bdrv_flush(bs);
2950 bdrv_drain(bs); /* in case flush left pending I/O */
2951
2952 bdrv_release_named_dirty_bitmaps(bs);
2953 assert(QLIST_EMPTY(&bs->dirty_bitmaps));
2954
2955 if (bs->drv) {
2956 BdrvChild *child, *next;
2957
2958 bs->drv->bdrv_close(bs);
2959 bs->drv = NULL;
2960
2961 bdrv_set_backing_hd(bs, NULL, &error_abort);
2962
2963 if (bs->file != NULL) {
2964 bdrv_unref_child(bs, bs->file);
2965 bs->file = NULL;
2966 }
2967
2968 QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
2969 /* TODO Remove bdrv_unref() from drivers' close function and use
2970 * bdrv_unref_child() here */
2971 if (child->bs->inherits_from == bs) {
2972 child->bs->inherits_from = NULL;
2973 }
2974 bdrv_detach_child(child);
2975 }
2976
2977 g_free(bs->opaque);
2978 bs->opaque = NULL;
2979 bs->copy_on_read = 0;
2980 bs->backing_file[0] = '\0';
2981 bs->backing_format[0] = '\0';
2982 bs->total_sectors = 0;
2983 bs->encrypted = false;
2984 bs->valid_key = false;
2985 bs->sg = false;
2986 QDECREF(bs->options);
2987 QDECREF(bs->explicit_options);
2988 bs->options = NULL;
2989 QDECREF(bs->full_open_options);
2990 bs->full_open_options = NULL;
2991 }
2992
2993 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
2994 g_free(ban);
2995 }
2996 QLIST_INIT(&bs->aio_notifiers);
2997 bdrv_drained_end(bs);
2998 }
2999
3000 void bdrv_close_all(void)
3001 {
3002 block_job_cancel_sync_all();
3003 nbd_export_close_all();
3004
3005 /* Drop references from requests still in flight, such as canceled block
3006 * jobs whose AIO context has not been polled yet */
3007 bdrv_drain_all();
3008
3009 blk_remove_all_bs();
3010 blockdev_close_all_bdrv_states();
3011
3012 assert(QTAILQ_EMPTY(&all_bdrv_states));
3013 }
3014
3015 static bool should_update_child(BdrvChild *c, BlockDriverState *to)
3016 {
3017 BdrvChild *to_c;
3018
3019 if (c->role->stay_at_node) {
3020 return false;
3021 }
3022
3023 if (c->role == &child_backing) {
3024 /* If @from is a backing file of @to, ignore the child to avoid
3025 * creating a loop. We only want to change the pointer of other
3026 * parents. */
3027 QLIST_FOREACH(to_c, &to->children, next) {
3028 if (to_c == c) {
3029 break;
3030 }
3031 }
3032 if (to_c) {
3033 return false;
3034 }
3035 }
3036
3037 return true;
3038 }
3039
3040 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
3041 Error **errp)
3042 {
3043 BdrvChild *c, *next;
3044 GSList *list = NULL, *p;
3045 uint64_t old_perm, old_shared;
3046 uint64_t perm = 0, shared = BLK_PERM_ALL;
3047 int ret;
3048
3049 assert(!atomic_read(&from->in_flight));
3050 assert(!atomic_read(&to->in_flight));
3051
3052 /* Make sure that @from doesn't go away until we have successfully attached
3053 * all of its parents to @to. */
3054 bdrv_ref(from);
3055
3056 /* Put all parents into @list and calculate their cumulative permissions */
3057 QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
3058 if (!should_update_child(c, to)) {
3059 continue;
3060 }
3061 list = g_slist_prepend(list, c);
3062 perm |= c->perm;
3063 shared &= c->shared_perm;
3064 }
3065
3066 /* Check whether the required permissions can be granted on @to, ignoring
3067 * all BdrvChild in @list so that they can't block themselves. */
3068 ret = bdrv_check_update_perm(to, perm, shared, list, errp);
3069 if (ret < 0) {
3070 bdrv_abort_perm_update(to);
3071 goto out;
3072 }
3073
3074 /* Now actually perform the change. We performed the permission check for
3075 * all elements of @list at once, so set the permissions all at once at the
3076 * very end. */
3077 for (p = list; p != NULL; p = p->next) {
3078 c = p->data;
3079
3080 bdrv_ref(to);
3081 bdrv_replace_child_noperm(c, to);
3082 bdrv_unref(from);
3083 }
3084
3085 bdrv_get_cumulative_perm(to, &old_perm, &old_shared);
3086 bdrv_set_perm(to, old_perm | perm, old_shared | shared);
3087
3088 out:
3089 g_slist_free(list);
3090 bdrv_unref(from);
3091 }
3092
3093 /*
3094 * Add new bs contents at the top of an image chain while the chain is
3095 * live, while keeping required fields on the top layer.
3096 *
3097 * This will modify the BlockDriverState fields, and swap contents
3098 * between bs_new and bs_top. Both bs_new and bs_top are modified.
3099 *
3100 * bs_new must not be attached to a BlockBackend.
3101 *
3102 * This function does not create any image files.
3103 *
3104 * bdrv_append() takes ownership of a bs_new reference and unrefs it because
3105 * that's what the callers commonly need. bs_new will be referenced by the old
3106 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a
3107 * reference of its own, it must call bdrv_ref().
3108 */
3109 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
3110 Error **errp)
3111 {
3112 Error *local_err = NULL;
3113
3114 bdrv_set_backing_hd(bs_new, bs_top, &local_err);
3115 if (local_err) {
3116 error_propagate(errp, local_err);
3117 goto out;
3118 }
3119
3120 bdrv_replace_node(bs_top, bs_new, &local_err);
3121 if (local_err) {
3122 error_propagate(errp, local_err);
3123 bdrv_set_backing_hd(bs_new, NULL, &error_abort);
3124 goto out;
3125 }
3126
3127 /* bs_new is now referenced by its new parents, we don't need the
3128 * additional reference any more. */
3129 out:
3130 bdrv_unref(bs_new);
3131 }
3132
3133 static void bdrv_delete(BlockDriverState *bs)
3134 {
3135 assert(!bs->job);
3136 assert(bdrv_op_blocker_is_empty(bs));
3137 assert(!bs->refcnt);
3138
3139 bdrv_close(bs);
3140
3141 /* remove from list, if necessary */
3142 if (bs->node_name[0] != '\0') {
3143 QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list);
3144 }
3145 QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list);
3146
3147 g_free(bs);
3148 }
3149
3150 /*
3151 * Run consistency checks on an image
3152 *
3153 * Returns 0 if the check could be completed (it doesn't mean that the image is
3154 * free of errors) or -errno when an internal error occurred. The results of the
3155 * check are stored in res.
3156 */
3157 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix)
3158 {
3159 if (bs->drv == NULL) {
3160 return -ENOMEDIUM;
3161 }
3162 if (bs->drv->bdrv_check == NULL) {
3163 return -ENOTSUP;
3164 }
3165
3166 memset(res, 0, sizeof(*res));
3167 return bs->drv->bdrv_check(bs, res, fix);
3168 }
3169
3170 /*
3171 * Return values:
3172 * 0 - success
3173 * -EINVAL - backing format specified, but no file
3174 * -ENOSPC - can't update the backing file because no space is left in the
3175 * image file header
3176 * -ENOTSUP - format driver doesn't support changing the backing file
3177 */
3178 int bdrv_change_backing_file(BlockDriverState *bs,
3179 const char *backing_file, const char *backing_fmt)
3180 {
3181 BlockDriver *drv = bs->drv;
3182 int ret;
3183
3184 /* Backing file format doesn't make sense without a backing file */
3185 if (backing_fmt && !backing_file) {
3186 return -EINVAL;
3187 }
3188
3189 if (drv->bdrv_change_backing_file != NULL) {
3190 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
3191 } else {
3192 ret = -ENOTSUP;
3193 }
3194
3195 if (ret == 0) {
3196 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
3197 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
3198 }
3199 return ret;
3200 }
3201
3202 /*
3203 * Finds the image layer in the chain that has 'bs' as its backing file.
3204 *
3205 * active is the current topmost image.
3206 *
3207 * Returns NULL if bs is not found in active's image chain,
3208 * or if active == bs.
3209 *
3210 * Returns the bottommost base image if bs == NULL.
3211 */
3212 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
3213 BlockDriverState *bs)
3214 {
3215 while (active && bs != backing_bs(active)) {
3216 active = backing_bs(active);
3217 }
3218
3219 return active;
3220 }
3221
3222 /* Given a BDS, searches for the base layer. */
3223 BlockDriverState *bdrv_find_base(BlockDriverState *bs)
3224 {
3225 return bdrv_find_overlay(bs, NULL);
3226 }
3227
3228 /*
3229 * Drops images above 'base' up to and including 'top', and sets the image
3230 * above 'top' to have base as its backing file.
3231 *
3232 * Requires that the overlay to 'top' is opened r/w, so that the backing file
3233 * information in 'bs' can be properly updated.
3234 *
3235 * E.g., this will convert the following chain:
3236 * bottom <- base <- intermediate <- top <- active
3237 *
3238 * to
3239 *
3240 * bottom <- base <- active
3241 *
3242 * It is allowed for bottom==base, in which case it converts:
3243 *
3244 * base <- intermediate <- top <- active
3245 *
3246 * to
3247 *
3248 * base <- active
3249 *
3250 * If backing_file_str is non-NULL, it will be used when modifying top's
3251 * overlay image metadata.
3252 *
3253 * Error conditions:
3254 * if active == top, that is considered an error
3255 *
3256 */
3257 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
3258 BlockDriverState *base, const char *backing_file_str)
3259 {
3260 BlockDriverState *new_top_bs = NULL;
3261 Error *local_err = NULL;
3262 int ret = -EIO;
3263
3264 if (!top->drv || !base->drv) {
3265 goto exit;
3266 }
3267
3268 new_top_bs = bdrv_find_overlay(active, top);
3269
3270 if (new_top_bs == NULL) {
3271 /* we could not find the image above 'top', this is an error */
3272 goto exit;
3273 }
3274
3275 /* special case of new_top_bs->backing->bs already pointing to base - nothing
3276 * to do, no intermediate images */
3277 if (backing_bs(new_top_bs) == base) {
3278 ret = 0;
3279 goto exit;
3280 }
3281
3282 /* Make sure that base is in the backing chain of top */
3283 if (!bdrv_chain_contains(top, base)) {
3284 goto exit;
3285 }
3286
3287 /* success - we can delete the intermediate states, and link top->base */
3288 backing_file_str = backing_file_str ? backing_file_str : base->filename;
3289 ret = bdrv_change_backing_file(new_top_bs, backing_file_str,
3290 base->drv ? base->drv->format_name : "");
3291 if (ret) {
3292 goto exit;
3293 }
3294
3295 bdrv_set_backing_hd(new_top_bs, base, &local_err);
3296 if (local_err) {
3297 ret = -EPERM;
3298 error_report_err(local_err);
3299 goto exit;
3300 }
3301
3302 ret = 0;
3303 exit:
3304 return ret;
3305 }
3306
3307 /**
3308 * Truncate file to 'offset' bytes (needed only for file protocols)
3309 */
3310 int bdrv_truncate(BdrvChild *child, int64_t offset)
3311 {
3312 BlockDriverState *bs = child->bs;
3313 BlockDriver *drv = bs->drv;
3314 int ret;
3315
3316 /* FIXME: Some format block drivers use this function instead of implicitly
3317 * growing their file by writing beyond its end.
3318 * See bdrv_aligned_pwritev() for an explanation why we currently
3319 * cannot assert this permission in that case. */
3320 // assert(child->perm & BLK_PERM_RESIZE);
3321
3322 if (!drv)
3323 return -ENOMEDIUM;
3324 if (!drv->bdrv_truncate)
3325 return -ENOTSUP;
3326 if (bs->read_only)
3327 return -EACCES;
3328
3329 ret = drv->bdrv_truncate(bs, offset);
3330 if (ret == 0) {
3331 ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
3332 bdrv_dirty_bitmap_truncate(bs);
3333 bdrv_parent_cb_resize(bs);
3334 ++bs->write_gen;
3335 }
3336 return ret;
3337 }
3338
3339 /**
3340 * Length of a allocated file in bytes. Sparse files are counted by actual
3341 * allocated space. Return < 0 if error or unknown.
3342 */
3343 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs)
3344 {
3345 BlockDriver *drv = bs->drv;
3346 if (!drv) {
3347 return -ENOMEDIUM;
3348 }
3349 if (drv->bdrv_get_allocated_file_size) {
3350 return drv->bdrv_get_allocated_file_size(bs);
3351 }
3352 if (bs->file) {
3353 return bdrv_get_allocated_file_size(bs->file->bs);
3354 }
3355 return -ENOTSUP;
3356 }
3357
3358 /**
3359 * Return number of sectors on success, -errno on error.
3360 */
3361 int64_t bdrv_nb_sectors(BlockDriverState *bs)
3362 {
3363 BlockDriver *drv = bs->drv;
3364
3365 if (!drv)
3366 return -ENOMEDIUM;
3367
3368 if (drv->has_variable_length) {
3369 int ret = refresh_total_sectors(bs, bs->total_sectors);
3370 if (ret < 0) {
3371 return ret;
3372 }
3373 }
3374 return bs->total_sectors;
3375 }
3376
3377 /**
3378 * Return length in bytes on success, -errno on error.
3379 * The length is always a multiple of BDRV_SECTOR_SIZE.
3380 */
3381 int64_t bdrv_getlength(BlockDriverState *bs)
3382 {
3383 int64_t ret = bdrv_nb_sectors(bs);
3384
3385 ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret;
3386 return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE;
3387 }
3388
3389 /* return 0 as number of sectors if no device present or error */
3390 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
3391 {
3392 int64_t nb_sectors = bdrv_nb_sectors(bs);
3393
3394 *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors;
3395 }
3396
3397 bool bdrv_is_sg(BlockDriverState *bs)
3398 {
3399 return bs->sg;
3400 }
3401
3402 bool bdrv_is_encrypted(BlockDriverState *bs)
3403 {
3404 if (bs->backing && bs->backing->bs->encrypted) {
3405 return true;
3406 }
3407 return bs->encrypted;
3408 }
3409
3410 bool bdrv_key_required(BlockDriverState *bs)
3411 {
3412 BdrvChild *backing = bs->backing;
3413
3414 if (backing && backing->bs->encrypted && !backing->bs->valid_key) {
3415 return true;
3416 }
3417 return (bs->encrypted && !bs->valid_key);
3418 }
3419
3420 int bdrv_set_key(BlockDriverState *bs, const char *key)
3421 {
3422 int ret;
3423 if (bs->backing && bs->backing->bs->encrypted) {
3424 ret = bdrv_set_key(bs->backing->bs, key);
3425 if (ret < 0)
3426 return ret;
3427 if (!bs->encrypted)
3428 return 0;
3429 }
3430 if (!bs->encrypted) {
3431 return -EINVAL;
3432 } else if (!bs->drv || !bs->drv->bdrv_set_key) {
3433 return -ENOMEDIUM;
3434 }
3435 ret = bs->drv->bdrv_set_key(bs, key);
3436 if (ret < 0) {
3437 bs->valid_key = false;
3438 } else if (!bs->valid_key) {
3439 /* call the change callback now, we skipped it on open */
3440 bs->valid_key = true;
3441 bdrv_parent_cb_change_media(bs, true);
3442 }
3443 return ret;
3444 }
3445
3446 /*
3447 * Provide an encryption key for @bs.
3448 * If @key is non-null:
3449 * If @bs is not encrypted, fail.
3450 * Else if the key is invalid, fail.
3451 * Else set @bs's key to @key, replacing the existing key, if any.
3452 * If @key is null:
3453 * If @bs is encrypted and still lacks a key, fail.
3454 * Else do nothing.
3455 * On failure, store an error object through @errp if non-null.
3456 */
3457 void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp)
3458 {
3459 if (key) {
3460 if (!bdrv_is_encrypted(bs)) {
3461 error_setg(errp, "Node '%s' is not encrypted",
3462 bdrv_get_device_or_node_name(bs));
3463 } else if (bdrv_set_key(bs, key) < 0) {
3464 error_setg(errp, QERR_INVALID_PASSWORD);
3465 }
3466 } else {
3467 if (bdrv_key_required(bs)) {
3468 error_set(errp, ERROR_CLASS_DEVICE_ENCRYPTED,
3469 "'%s' (%s) is encrypted",
3470 bdrv_get_device_or_node_name(bs),
3471 bdrv_get_encrypted_filename(bs));
3472 }
3473 }
3474 }
3475
3476 const char *bdrv_get_format_name(BlockDriverState *bs)
3477 {
3478 return bs->drv ? bs->drv->format_name : NULL;
3479 }
3480
3481 static int qsort_strcmp(const void *a, const void *b)
3482 {
3483 return strcmp(*(char *const *)a, *(char *const *)b);
3484 }
3485
3486 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
3487 void *opaque)
3488 {
3489 BlockDriver *drv;
3490 int count = 0;
3491 int i;
3492 const char **formats = NULL;
3493
3494 QLIST_FOREACH(drv, &bdrv_drivers, list) {
3495 if (drv->format_name) {
3496 bool found = false;
3497 int i = count;
3498 while (formats && i && !found) {
3499 found = !strcmp(formats[--i], drv->format_name);
3500 }
3501
3502 if (!found) {
3503 formats = g_renew(const char *, formats, count + 1);
3504 formats[count++] = drv->format_name;
3505 }
3506 }
3507 }
3508
3509 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); i++) {
3510 const char *format_name = block_driver_modules[i].format_name;
3511
3512 if (format_name) {
3513 bool found = false;
3514 int j = count;
3515
3516 while (formats && j && !found) {
3517 found = !strcmp(formats[--j], format_name);
3518 }
3519
3520 if (!found) {
3521 formats = g_renew(const char *, formats, count + 1);
3522 formats[count++] = format_name;
3523 }
3524 }
3525 }
3526
3527 qsort(formats, count, sizeof(formats[0]), qsort_strcmp);
3528
3529 for (i = 0; i < count; i++) {
3530 it(opaque, formats[i]);
3531 }
3532
3533 g_free(formats);
3534 }
3535
3536 /* This function is to find a node in the bs graph */
3537 BlockDriverState *bdrv_find_node(const char *node_name)
3538 {
3539 BlockDriverState *bs;
3540
3541 assert(node_name);
3542
3543 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
3544 if (!strcmp(node_name, bs->node_name)) {
3545 return bs;
3546 }
3547 }
3548 return NULL;
3549 }
3550
3551 /* Put this QMP function here so it can access the static graph_bdrv_states. */
3552 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp)
3553 {
3554 BlockDeviceInfoList *list, *entry;
3555 BlockDriverState *bs;
3556
3557 list = NULL;
3558 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
3559 BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, errp);
3560 if (!info) {
3561 qapi_free_BlockDeviceInfoList(list);
3562 return NULL;
3563 }
3564 entry = g_malloc0(sizeof(*entry));
3565 entry->value = info;
3566 entry->next = list;
3567 list = entry;
3568 }
3569
3570 return list;
3571 }
3572
3573 BlockDriverState *bdrv_lookup_bs(const char *device,
3574 const char *node_name,
3575 Error **errp)
3576 {
3577 BlockBackend *blk;