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
25#include "qemu/osdep.h"
26#include "block/trace.h"
27#include "block/block_int.h"
28#include "block/blockjob.h"
29#include "block/nbd.h"
30#include "block/qdict.h"
31#include "qemu/error-report.h"
32#include "module_block.h"
33#include "qemu/main-loop.h"
34#include "qemu/module.h"
35#include "qapi/error.h"
36#include "qapi/qmp/qdict.h"
37#include "qapi/qmp/qjson.h"
38#include "qapi/qmp/qnull.h"
39#include "qapi/qmp/qstring.h"
40#include "qapi/qobject-output-visitor.h"
41#include "qapi/qapi-visit-block-core.h"
42#include "sysemu/block-backend.h"
43#include "sysemu/sysemu.h"
44#include "qemu/notify.h"
45#include "qemu/option.h"
46#include "qemu/coroutine.h"
47#include "block/qapi.h"
48#include "qemu/timer.h"
49#include "qemu/cutils.h"
50#include "qemu/id.h"
51
52#ifdef CONFIG_BSD
53#include <sys/ioctl.h>
54#include <sys/queue.h>
55#ifndef __DragonFly__
56#include <sys/disk.h>
57#endif
58#endif
59
60#ifdef _WIN32
61#include <windows.h>
62#endif
63
64#define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
65
66static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states =
67 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states);
68
69static QTAILQ_HEAD(, BlockDriverState) all_bdrv_states =
70 QTAILQ_HEAD_INITIALIZER(all_bdrv_states);
71
72static QLIST_HEAD(, BlockDriver) bdrv_drivers =
73 QLIST_HEAD_INITIALIZER(bdrv_drivers);
74
75static BlockDriverState *bdrv_open_inherit(const char *filename,
76 const char *reference,
77 QDict *options, int flags,
78 BlockDriverState *parent,
79 const BdrvChildRole *child_role,
80 Error **errp);
81
82/* If non-zero, use only whitelisted block drivers */
83static int use_bdrv_whitelist;
84
85#ifdef _WIN32
86static int is_windows_drive_prefix(const char *filename)
87{
88 return (((filename[0] >= 'a' && filename[0] <= 'z') ||
89 (filename[0] >= 'A' && filename[0] <= 'Z')) &&
90 filename[1] == ':');
91}
92
93int is_windows_drive(const char *filename)
94{
95 if (is_windows_drive_prefix(filename) &&
96 filename[2] == '\0')
97 return 1;
98 if (strstart(filename, "\\\\.\\", NULL) ||
99 strstart(filename, "//./", NULL))
100 return 1;
101 return 0;
102}
103#endif
104
105size_t bdrv_opt_mem_align(BlockDriverState *bs)
106{
107 if (!bs || !bs->drv) {
108 /* page size or 4k (hdd sector size) should be on the safe side */
109 return MAX(4096, getpagesize());
110 }
111
112 return bs->bl.opt_mem_alignment;
113}
114
115size_t bdrv_min_mem_align(BlockDriverState *bs)
116{
117 if (!bs || !bs->drv) {
118 /* page size or 4k (hdd sector size) should be on the safe side */
119 return MAX(4096, getpagesize());
120 }
121
122 return bs->bl.min_mem_alignment;
123}
124
125/* check if the path starts with "<protocol>:" */
126int path_has_protocol(const char *path)
127{
128 const char *p;
129
130#ifdef _WIN32
131 if (is_windows_drive(path) ||
132 is_windows_drive_prefix(path)) {
133 return 0;
134 }
135 p = path + strcspn(path, ":/\\");
136#else
137 p = path + strcspn(path, ":/");
138#endif
139
140 return *p == ':';
141}
142
143int path_is_absolute(const char *path)
144{
145#ifdef _WIN32
146 /* specific case for names like: "\\.\d:" */
147 if (is_windows_drive(path) || is_windows_drive_prefix(path)) {
148 return 1;
149 }
150 return (*path == '/' || *path == '\\');
151#else
152 return (*path == '/');
153#endif
154}
155
156/* if filename is absolute, just return its duplicate. Otherwise, build a
157 path to it by considering it is relative to base_path. URL are
158 supported. */
159char *path_combine(const char *base_path, const char *filename)
160{
161 const char *protocol_stripped = NULL;
162 const char *p, *p1;
163 char *result;
164 int len;
165
166 if (path_is_absolute(filename)) {
167 return g_strdup(filename);
168 }
169
170 if (path_has_protocol(base_path)) {
171 protocol_stripped = strchr(base_path, ':');
172 if (protocol_stripped) {
173 protocol_stripped++;
174 }
175 }
176 p = protocol_stripped ?: base_path;
177
178 p1 = strrchr(base_path, '/');
179#ifdef _WIN32
180 {
181 const char *p2;
182 p2 = strrchr(base_path, '\\');
183 if (!p1 || p2 > p1) {
184 p1 = p2;
185 }
186 }
187#endif
188 if (p1) {
189 p1++;
190 } else {
191 p1 = base_path;
192 }
193 if (p1 > p) {
194 p = p1;
195 }
196 len = p - base_path;
197
198 result = g_malloc(len + strlen(filename) + 1);
199 memcpy(result, base_path, len);
200 strcpy(result + len, filename);
201
202 return result;
203}
204
205/*
206 * Helper function for bdrv_parse_filename() implementations to remove optional
207 * protocol prefixes (especially "file:") from a filename and for putting the
208 * stripped filename into the options QDict if there is such a prefix.
209 */
210void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix,
211 QDict *options)
212{
213 if (strstart(filename, prefix, &filename)) {
214 /* Stripping the explicit protocol prefix may result in a protocol
215 * prefix being (wrongly) detected (if the filename contains a colon) */
216 if (path_has_protocol(filename)) {
217 QString *fat_filename;
218
219 /* This means there is some colon before the first slash; therefore,
220 * this cannot be an absolute path */
221 assert(!path_is_absolute(filename));
222
223 /* And we can thus fix the protocol detection issue by prefixing it
224 * by "./" */
225 fat_filename = qstring_from_str("./");
226 qstring_append(fat_filename, filename);
227
228 assert(!path_has_protocol(qstring_get_str(fat_filename)));
229
230 qdict_put(options, "filename", fat_filename);
231 } else {
232 /* If no protocol prefix was detected, we can use the shortened
233 * filename as-is */
234 qdict_put_str(options, "filename", filename);
235 }
236 }
237}
238
239
240/* Returns whether the image file is opened as read-only. Note that this can
241 * return false and writing to the image file is still not possible because the
242 * image is inactivated. */
243bool bdrv_is_read_only(BlockDriverState *bs)
244{
245 return bs->read_only;
246}
247
248int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
249 bool ignore_allow_rdw, Error **errp)
250{
251 /* Do not set read_only if copy_on_read is enabled */
252 if (bs->copy_on_read && read_only) {
253 error_setg(errp, "Can't set node '%s' to r/o with copy-on-read enabled",
254 bdrv_get_device_or_node_name(bs));
255 return -EINVAL;
256 }
257
258 /* Do not clear read_only if it is prohibited */
259 if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR) &&
260 !ignore_allow_rdw)
261 {
262 error_setg(errp, "Node '%s' is read only",
263 bdrv_get_device_or_node_name(bs));
264 return -EPERM;
265 }
266
267 return 0;
268}
269
270/*
271 * Called by a driver that can only provide a read-only image.
272 *
273 * Returns 0 if the node is already read-only or it could switch the node to
274 * read-only because BDRV_O_AUTO_RDONLY is set.
275 *
276 * Returns -EACCES if the node is read-write and BDRV_O_AUTO_RDONLY is not set
277 * or bdrv_can_set_read_only() forbids making the node read-only. If @errmsg
278 * is not NULL, it is used as the error message for the Error object.
279 */
280int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
281 Error **errp)
282{
283 int ret = 0;
284
285 if (!(bs->open_flags & BDRV_O_RDWR)) {
286 return 0;
287 }
288 if (!(bs->open_flags & BDRV_O_AUTO_RDONLY)) {
289 goto fail;
290 }
291
292 ret = bdrv_can_set_read_only(bs, true, false, NULL);
293 if (ret < 0) {
294 goto fail;
295 }
296
297 bs->read_only = true;
298 bs->open_flags &= ~BDRV_O_RDWR;
299
300 return 0;
301
302fail:
303 error_setg(errp, "%s", errmsg ?: "Image is read-only");
304 return -EACCES;
305}
306
307/*
308 * If @backing is empty, this function returns NULL without setting
309 * @errp. In all other cases, NULL will only be returned with @errp
310 * set.
311 *
312 * Therefore, a return value of NULL without @errp set means that
313 * there is no backing file; if @errp is set, there is one but its
314 * absolute filename cannot be generated.
315 */
316char *bdrv_get_full_backing_filename_from_filename(const char *backed,
317 const char *backing,
318 Error **errp)
319{
320 if (backing[0] == '\0') {
321 return NULL;
322 } else if (path_has_protocol(backing) || path_is_absolute(backing)) {
323 return g_strdup(backing);
324 } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) {
325 error_setg(errp, "Cannot use relative backing file names for '%s'",
326 backed);
327 return NULL;
328 } else {
329 return path_combine(backed, backing);
330 }
331}
332
333/*
334 * If @filename is empty or NULL, this function returns NULL without
335 * setting @errp. In all other cases, NULL will only be returned with
336 * @errp set.
337 */
338static char *bdrv_make_absolute_filename(BlockDriverState *relative_to,
339 const char *filename, Error **errp)
340{
341 char *dir, *full_name;
342
343 if (!filename || filename[0] == '\0') {
344 return NULL;
345 } else if (path_has_protocol(filename) || path_is_absolute(filename)) {
346 return g_strdup(filename);
347 }
348
349 dir = bdrv_dirname(relative_to, errp);
350 if (!dir) {
351 return NULL;
352 }
353
354 full_name = g_strconcat(dir, filename, NULL);
355 g_free(dir);
356 return full_name;
357}
358
359char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp)
360{
361 return bdrv_make_absolute_filename(bs, bs->backing_file, errp);
362}
363
364void bdrv_register(BlockDriver *bdrv)
365{
366 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list);
367}
368
369BlockDriverState *bdrv_new(void)
370{
371 BlockDriverState *bs;
372 int i;
373
374 bs = g_new0(BlockDriverState, 1);
375 QLIST_INIT(&bs->dirty_bitmaps);
376 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
377 QLIST_INIT(&bs->op_blockers[i]);
378 }
379 notifier_with_return_list_init(&bs->before_write_notifiers);
380 qemu_co_mutex_init(&bs->reqs_lock);
381 qemu_mutex_init(&bs->dirty_bitmap_mutex);
382 bs->refcnt = 1;
383 bs->aio_context = qemu_get_aio_context();
384
385 qemu_co_queue_init(&bs->flush_queue);
386
387 for (i = 0; i < bdrv_drain_all_count; i++) {
388 bdrv_drained_begin(bs);
389 }
390
391 QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list);
392
393 return bs;
394}
395
396static BlockDriver *bdrv_do_find_format(const char *format_name)
397{
398 BlockDriver *drv1;
399
400 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
401 if (!strcmp(drv1->format_name, format_name)) {
402 return drv1;
403 }
404 }
405
406 return NULL;
407}
408
409BlockDriver *bdrv_find_format(const char *format_name)
410{
411 BlockDriver *drv1;
412 int i;
413
414 drv1 = bdrv_do_find_format(format_name);
415 if (drv1) {
416 return drv1;
417 }
418
419 /* The driver isn't registered, maybe we need to load a module */
420 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
421 if (!strcmp(block_driver_modules[i].format_name, format_name)) {
422 block_module_load_one(block_driver_modules[i].library_name);
423 break;
424 }
425 }
426
427 return bdrv_do_find_format(format_name);
428}
429
430static int bdrv_format_is_whitelisted(const char *format_name, bool read_only)
431{
432 static const char *whitelist_rw[] = {
433 CONFIG_BDRV_RW_WHITELIST
434 };
435 static const char *whitelist_ro[] = {
436 CONFIG_BDRV_RO_WHITELIST
437 };
438 const char **p;
439
440 if (!whitelist_rw[0] && !whitelist_ro[0]) {
441 return 1; /* no whitelist, anything goes */
442 }
443
444 for (p = whitelist_rw; *p; p++) {
445 if (!strcmp(format_name, *p)) {
446 return 1;
447 }
448 }
449 if (read_only) {
450 for (p = whitelist_ro; *p; p++) {
451 if (!strcmp(format_name, *p)) {
452 return 1;
453 }
454 }
455 }
456 return 0;
457}
458
459int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
460{
461 return bdrv_format_is_whitelisted(drv->format_name, read_only);
462}
463
464bool bdrv_uses_whitelist(void)
465{
466 return use_bdrv_whitelist;
467}
468
469typedef struct CreateCo {
470 BlockDriver *drv;
471 char *filename;
472 QemuOpts *opts;
473 int ret;
474 Error *err;
475} CreateCo;
476
477static void coroutine_fn bdrv_create_co_entry(void *opaque)
478{
479 Error *local_err = NULL;
480 int ret;
481
482 CreateCo *cco = opaque;
483 assert(cco->drv);
484
485 ret = cco->drv->bdrv_co_create_opts(cco->filename, cco->opts, &local_err);
486 error_propagate(&cco->err, local_err);
487 cco->ret = ret;
488}
489
490int bdrv_create(BlockDriver *drv, const char* filename,
491 QemuOpts *opts, Error **errp)
492{
493 int ret;
494
495 Coroutine *co;
496 CreateCo cco = {
497 .drv = drv,
498 .filename = g_strdup(filename),
499 .opts = opts,
500 .ret = NOT_DONE,
501 .err = NULL,
502 };
503
504 if (!drv->bdrv_co_create_opts) {
505 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name);
506 ret = -ENOTSUP;
507 goto out;
508 }
509
510 if (qemu_in_coroutine()) {
511 /* Fast-path if already in coroutine context */
512 bdrv_create_co_entry(&cco);
513 } else {
514 co = qemu_coroutine_create(bdrv_create_co_entry, &cco);
515 qemu_coroutine_enter(co);
516 while (cco.ret == NOT_DONE) {
517 aio_poll(qemu_get_aio_context(), true);
518 }
519 }
520
521 ret = cco.ret;
522 if (ret < 0) {
523 if (cco.err) {
524 error_propagate(errp, cco.err);
525 } else {
526 error_setg_errno(errp, -ret, "Could not create image");
527 }
528 }
529
530out:
531 g_free(cco.filename);
532 return ret;
533}
534
535int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
536{
537 BlockDriver *drv;
538 Error *local_err = NULL;
539 int ret;
540
541 drv = bdrv_find_protocol(filename, true, errp);
542 if (drv == NULL) {
543 return -ENOENT;
544 }
545
546 ret = bdrv_create(drv, filename, opts, &local_err);
547 error_propagate(errp, local_err);
548 return ret;
549}
550
551/**
552 * Try to get @bs's logical and physical block size.
553 * On success, store them in @bsz struct and return 0.
554 * On failure return -errno.
555 * @bs must not be empty.
556 */
557int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
558{
559 BlockDriver *drv = bs->drv;
560
561 if (drv && drv->bdrv_probe_blocksizes) {
562 return drv->bdrv_probe_blocksizes(bs, bsz);
563 } else if (drv && drv->is_filter && bs->file) {
564 return bdrv_probe_blocksizes(bs->file->bs, bsz);
565 }
566
567 return -ENOTSUP;
568}
569
570/**
571 * Try to get @bs's geometry (cyls, heads, sectors).
572 * On success, store them in @geo struct and return 0.
573 * On failure return -errno.
574 * @bs must not be empty.
575 */
576int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
577{
578 BlockDriver *drv = bs->drv;
579
580 if (drv && drv->bdrv_probe_geometry) {
581 return drv->bdrv_probe_geometry(bs, geo);
582 } else if (drv && drv->is_filter && bs->file) {
583 return bdrv_probe_geometry(bs->file->bs, geo);
584 }
585
586 return -ENOTSUP;
587}
588
589/*
590 * Create a uniquely-named empty temporary file.
591 * Return 0 upon success, otherwise a negative errno value.
592 */
593int get_tmp_filename(char *filename, int size)
594{
595#ifdef _WIN32
596 char temp_dir[MAX_PATH];
597 /* GetTempFileName requires that its output buffer (4th param)
598 have length MAX_PATH or greater. */
599 assert(size >= MAX_PATH);
600 return (GetTempPath(MAX_PATH, temp_dir)
601 && GetTempFileName(temp_dir, "qem", 0, filename)
602 ? 0 : -GetLastError());
603#else
604 int fd;
605 const char *tmpdir;
606 tmpdir = getenv("TMPDIR");
607 if (!tmpdir) {
608 tmpdir = "/var/tmp";
609 }
610 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) {
611 return -EOVERFLOW;
612 }
613 fd = mkstemp(filename);
614 if (fd < 0) {
615 return -errno;
616 }
617 if (close(fd) != 0) {
618 unlink(filename);
619 return -errno;
620 }
621 return 0;
622#endif
623}
624
625/*
626 * Detect host devices. By convention, /dev/cdrom[N] is always
627 * recognized as a host CDROM.
628 */
629static BlockDriver *find_hdev_driver(const char *filename)
630{
631 int score_max = 0, score;
632 BlockDriver *drv = NULL, *d;
633
634 QLIST_FOREACH(d, &bdrv_drivers, list) {
635 if (d->bdrv_probe_device) {
636 score = d->bdrv_probe_device(filename);
637 if (score > score_max) {
638 score_max = score;
639 drv = d;
640 }
641 }
642 }
643
644 return drv;
645}
646
647static BlockDriver *bdrv_do_find_protocol(const char *protocol)
648{
649 BlockDriver *drv1;
650
651 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
652 if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) {
653 return drv1;
654 }
655 }
656
657 return NULL;
658}
659
660BlockDriver *bdrv_find_protocol(const char *filename,
661 bool allow_protocol_prefix,
662 Error **errp)
663{
664 BlockDriver *drv1;
665 char protocol[128];
666 int len;
667 const char *p;
668 int i;
669
670 /* TODO Drivers without bdrv_file_open must be specified explicitly */
671
672 /*
673 * XXX(hch): we really should not let host device detection
674 * override an explicit protocol specification, but moving this
675 * later breaks access to device names with colons in them.
676 * Thanks to the brain-dead persistent naming schemes on udev-
677 * based Linux systems those actually are quite common.
678 */
679 drv1 = find_hdev_driver(filename);
680 if (drv1) {
681 return drv1;
682 }
683
684 if (!path_has_protocol(filename) || !allow_protocol_prefix) {
685 return &bdrv_file;
686 }
687
688 p = strchr(filename, ':');
689 assert(p != NULL);
690 len = p - filename;
691 if (len > sizeof(protocol) - 1)
692 len = sizeof(protocol) - 1;
693 memcpy(protocol, filename, len);
694 protocol[len] = '\0';
695
696 drv1 = bdrv_do_find_protocol(protocol);
697 if (drv1) {
698 return drv1;
699 }
700
701 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
702 if (block_driver_modules[i].protocol_name &&
703 !strcmp(block_driver_modules[i].protocol_name, protocol)) {
704 block_module_load_one(block_driver_modules[i].library_name);
705 break;
706 }
707 }
708
709 drv1 = bdrv_do_find_protocol(protocol);
710 if (!drv1) {
711 error_setg(errp, "Unknown protocol '%s'", protocol);
712 }
713 return drv1;
714}
715
716/*
717 * Guess image format by probing its contents.
718 * This is not a good idea when your image is raw (CVE-2008-2004), but
719 * we do it anyway for backward compatibility.
720 *
721 * @buf contains the image's first @buf_size bytes.
722 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
723 * but can be smaller if the image file is smaller)
724 * @filename is its filename.
725 *
726 * For all block drivers, call the bdrv_probe() method to get its
727 * probing score.
728 * Return the first block driver with the highest probing score.
729 */
730BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
731 const char *filename)
732{
733 int score_max = 0, score;
734 BlockDriver *drv = NULL, *d;
735
736 QLIST_FOREACH(d, &bdrv_drivers, list) {
737 if (d->bdrv_probe) {
738 score = d->bdrv_probe(buf, buf_size, filename);
739 if (score > score_max) {
740 score_max = score;
741 drv = d;
742 }
743 }
744 }
745
746 return drv;
747}
748
749static int find_image_format(BlockBackend *file, const char *filename,
750 BlockDriver **pdrv, Error **errp)
751{
752 BlockDriver *drv;
753 uint8_t buf[BLOCK_PROBE_BUF_SIZE];
754 int ret = 0;
755
756 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
757 if (blk_is_sg(file) || !blk_is_inserted(file) || blk_getlength(file) == 0) {
758 *pdrv = &bdrv_raw;
759 return ret;
760 }
761
762 ret = blk_pread(file, 0, buf, sizeof(buf));
763 if (ret < 0) {
764 error_setg_errno(errp, -ret, "Could not read image for determining its "
765 "format");
766 *pdrv = NULL;
767 return ret;
768 }
769
770 drv = bdrv_probe_all(buf, ret, filename);
771 if (!drv) {
772 error_setg(errp, "Could not determine image format: No compatible "
773 "driver found");
774 ret = -ENOENT;
775 }
776 *pdrv = drv;
777 return ret;
778}
779
780/**
781 * Set the current 'total_sectors' value
782 * Return 0 on success, -errno on error.
783 */
784int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
785{
786 BlockDriver *drv = bs->drv;
787
788 if (!drv) {
789 return -ENOMEDIUM;
790 }
791
792 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
793 if (bdrv_is_sg(bs))
794 return 0;
795
796 /* query actual device if possible, otherwise just trust the hint */
797 if (drv->bdrv_getlength) {
798 int64_t length = drv->bdrv_getlength(bs);
799 if (length < 0) {
800 return length;
801 }
802 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE);
803 }
804
805 bs->total_sectors = hint;
806 return 0;
807}
808
809/**
810 * Combines a QDict of new block driver @options with any missing options taken
811 * from @old_options, so that leaving out an option defaults to its old value.
812 */
813static void bdrv_join_options(BlockDriverState *bs, QDict *options,
814 QDict *old_options)
815{
816 if (bs->drv && bs->drv->bdrv_join_options) {
817 bs->drv->bdrv_join_options(options, old_options);
818 } else {
819 qdict_join(options, old_options, false);
820 }
821}
822
823static BlockdevDetectZeroesOptions bdrv_parse_detect_zeroes(QemuOpts *opts,
824 int open_flags,
825 Error **errp)
826{
827 Error *local_err = NULL;
828 char *value = qemu_opt_get_del(opts, "detect-zeroes");
829 BlockdevDetectZeroesOptions detect_zeroes =
830 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup, value,
831 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF, &local_err);
832 g_free(value);
833 if (local_err) {
834 error_propagate(errp, local_err);
835 return detect_zeroes;
836 }
837
838 if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
839 !(open_flags & BDRV_O_UNMAP))
840 {
841 error_setg(errp, "setting detect-zeroes to unmap is not allowed "
842 "without setting discard operation to unmap");
843 }
844
845 return detect_zeroes;
846}
847
848/**
849 * Set open flags for a given discard mode
850 *
851 * Return 0 on success, -1 if the discard mode was invalid.
852 */
853int bdrv_parse_discard_flags(const char *mode, int *flags)
854{
855 *flags &= ~BDRV_O_UNMAP;
856
857 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) {
858 /* do nothing */
859 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) {
860 *flags |= BDRV_O_UNMAP;
861 } else {
862 return -1;
863 }
864
865 return 0;
866}
867
868/**
869 * Set open flags for a given cache mode
870 *
871 * Return 0 on success, -1 if the cache mode was invalid.
872 */
873int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough)
874{
875 *flags &= ~BDRV_O_CACHE_MASK;
876
877 if (!strcmp(mode, "off") || !strcmp(mode, "none")) {
878 *writethrough = false;
879 *flags |= BDRV_O_NOCACHE;
880 } else if (!strcmp(mode, "directsync")) {
881 *writethrough = true;
882 *flags |= BDRV_O_NOCACHE;
883 } else if (!strcmp(mode, "writeback")) {
884 *writethrough = false;
885 } else if (!strcmp(mode, "unsafe")) {
886 *writethrough = false;
887 *flags |= BDRV_O_NO_FLUSH;
888 } else if (!strcmp(mode, "writethrough")) {
889 *writethrough = true;
890 } else {
891 return -1;
892 }
893
894 return 0;
895}
896
897static char *bdrv_child_get_parent_desc(BdrvChild *c)
898{
899 BlockDriverState *parent = c->opaque;
900 return g_strdup(bdrv_get_device_or_node_name(parent));
901}
902
903static void bdrv_child_cb_drained_begin(BdrvChild *child)
904{
905 BlockDriverState *bs = child->opaque;
906 bdrv_do_drained_begin_quiesce(bs, NULL, false);
907}
908
909static bool bdrv_child_cb_drained_poll(BdrvChild *child)
910{
911 BlockDriverState *bs = child->opaque;
912 return bdrv_drain_poll(bs, false, NULL, false);
913}
914
915static void bdrv_child_cb_drained_end(BdrvChild *child,
916 int *drained_end_counter)
917{
918 BlockDriverState *bs = child->opaque;
919 bdrv_drained_end_no_poll(bs, drained_end_counter);
920}
921
922static void bdrv_child_cb_attach(BdrvChild *child)
923{
924 BlockDriverState *bs = child->opaque;
925 bdrv_apply_subtree_drain(child, bs);
926}
927
928static void bdrv_child_cb_detach(BdrvChild *child)
929{
930 BlockDriverState *bs = child->opaque;
931 bdrv_unapply_subtree_drain(child, bs);
932}
933
934static int bdrv_child_cb_inactivate(BdrvChild *child)
935{
936 BlockDriverState *bs = child->opaque;
937 assert(bs->open_flags & BDRV_O_INACTIVE);
938 return 0;
939}
940
941static bool bdrv_child_cb_can_set_aio_ctx(BdrvChild *child, AioContext *ctx,
942 GSList **ignore, Error **errp)
943{
944 BlockDriverState *bs = child->opaque;
945 return bdrv_can_set_aio_context(bs, ctx, ignore, errp);
946}
947
948static void bdrv_child_cb_set_aio_ctx(BdrvChild *child, AioContext *ctx,
949 GSList **ignore)
950{
951 BlockDriverState *bs = child->opaque;
952 return bdrv_set_aio_context_ignore(bs, ctx, ignore);
953}
954
955/*
956 * Returns the options and flags that a temporary snapshot should get, based on
957 * the originally requested flags (the originally requested image will have
958 * flags like a backing file)
959 */
960static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
961 int parent_flags, QDict *parent_options)
962{
963 *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY;
964
965 /* For temporary files, unconditional cache=unsafe is fine */
966 qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off");
967 qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
968
969 /* Copy the read-only and discard options from the parent */
970 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
971 qdict_copy_default(child_options, parent_options, BDRV_OPT_DISCARD);
972
973 /* aio=native doesn't work for cache.direct=off, so disable it for the
974 * temporary snapshot */
975 *child_flags &= ~BDRV_O_NATIVE_AIO;
976}
977
978/*
979 * Returns the options and flags that bs->file should get if a protocol driver
980 * is expected, based on the given options and flags for the parent BDS
981 */
982static void bdrv_inherited_options(int *child_flags, QDict *child_options,
983 int parent_flags, QDict *parent_options)
984{
985 int flags = parent_flags;
986
987 /* Enable protocol handling, disable format probing for bs->file */
988 flags |= BDRV_O_PROTOCOL;
989
990 /* If the cache mode isn't explicitly set, inherit direct and no-flush from
991 * the parent. */
992 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
993 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
994 qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
995
996 /* Inherit the read-only option from the parent if it's not set */
997 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
998 qdict_copy_default(child_options, parent_options, BDRV_OPT_AUTO_READ_ONLY);
999
1000 /* Our block drivers take care to send flushes and respect unmap policy,
1001 * so we can default to enable both on lower layers regardless of the
1002 * corresponding parent options. */
1003 qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap");
1004
1005 /* Clear flags that only apply to the top layer */
1006 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ |
1007 BDRV_O_NO_IO);
1008
1009 *child_flags = flags;
1010}
1011
1012const BdrvChildRole child_file = {
1013 .parent_is_bds = true,
1014 .get_parent_desc = bdrv_child_get_parent_desc,
1015 .inherit_options = bdrv_inherited_options,
1016 .drained_begin = bdrv_child_cb_drained_begin,
1017 .drained_poll = bdrv_child_cb_drained_poll,
1018 .drained_end = bdrv_child_cb_drained_end,
1019 .attach = bdrv_child_cb_attach,
1020 .detach = bdrv_child_cb_detach,
1021 .inactivate = bdrv_child_cb_inactivate,
1022 .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx,
1023 .set_aio_ctx = bdrv_child_cb_set_aio_ctx,
1024};
1025
1026/*
1027 * Returns the options and flags that bs->file should get if the use of formats
1028 * (and not only protocols) is permitted for it, based on the given options and
1029 * flags for the parent BDS
1030 */
1031static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options,
1032 int parent_flags, QDict *parent_options)
1033{
1034 child_file.inherit_options(child_flags, child_options,
1035 parent_flags, parent_options);
1036
1037 *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO);
1038}
1039
1040const BdrvChildRole child_format = {
1041 .parent_is_bds = true,
1042 .get_parent_desc = bdrv_child_get_parent_desc,
1043 .inherit_options = bdrv_inherited_fmt_options,
1044 .drained_begin = bdrv_child_cb_drained_begin,
1045 .drained_poll = bdrv_child_cb_drained_poll,
1046 .drained_end = bdrv_child_cb_drained_end,
1047 .attach = bdrv_child_cb_attach,
1048 .detach = bdrv_child_cb_detach,
1049 .inactivate = bdrv_child_cb_inactivate,
1050 .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx,
1051 .set_aio_ctx = bdrv_child_cb_set_aio_ctx,
1052};
1053
1054static void bdrv_backing_attach(BdrvChild *c)
1055{
1056 BlockDriverState *parent = c->opaque;
1057 BlockDriverState *backing_hd = c->bs;
1058
1059 assert(!parent->backing_blocker);
1060 error_setg(&parent->backing_blocker,
1061 "node is used as backing hd of '%s'",
1062 bdrv_get_device_or_node_name(parent));
1063
1064 bdrv_refresh_filename(backing_hd);
1065
1066 parent->open_flags &= ~BDRV_O_NO_BACKING;
1067 pstrcpy(parent->backing_file, sizeof(parent->backing_file),
1068 backing_hd->filename);
1069 pstrcpy(parent->backing_format, sizeof(parent->backing_format),
1070 backing_hd->drv ? backing_hd->drv->format_name : "");
1071
1072 bdrv_op_block_all(backing_hd, parent->backing_blocker);
1073 /* Otherwise we won't be able to commit or stream */
1074 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,
1075 parent->backing_blocker);
1076 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_STREAM,
1077 parent->backing_blocker);
1078 /*
1079 * We do backup in 3 ways:
1080 * 1. drive backup
1081 * The target bs is new opened, and the source is top BDS
1082 * 2. blockdev backup
1083 * Both the source and the target are top BDSes.
1084 * 3. internal backup(used for block replication)
1085 * Both the source and the target are backing file
1086 *
1087 * In case 1 and 2, neither the source nor the target is the backing file.
1088 * In case 3, we will block the top BDS, so there is only one block job
1089 * for the top BDS and its backing chain.
1090 */
1091 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_SOURCE,
1092 parent->backing_blocker);
1093 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_TARGET,
1094 parent->backing_blocker);
1095
1096 bdrv_child_cb_attach(c);
1097}
1098
1099static void bdrv_backing_detach(BdrvChild *c)
1100{
1101 BlockDriverState *parent = c->opaque;
1102
1103 assert(parent->backing_blocker);
1104 bdrv_op_unblock_all(c->bs, parent->backing_blocker);
1105 error_free(parent->backing_blocker);
1106 parent->backing_blocker = NULL;
1107
1108 bdrv_child_cb_detach(c);
1109}
1110
1111/*
1112 * Returns the options and flags that bs->backing should get, based on the
1113 * given options and flags for the parent BDS
1114 */
1115static void bdrv_backing_options(int *child_flags, QDict *child_options,
1116 int parent_flags, QDict *parent_options)
1117{
1118 int flags = parent_flags;
1119
1120 /* The cache mode is inherited unmodified for backing files; except WCE,
1121 * which is only applied on the top level (BlockBackend) */
1122 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
1123 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
1124 qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
1125
1126 /* backing files always opened read-only */
1127 qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on");
1128 qdict_set_default_str(child_options, BDRV_OPT_AUTO_READ_ONLY, "off");
1129 flags &= ~BDRV_O_COPY_ON_READ;
1130
1131 /* snapshot=on is handled on the top layer */
1132 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY);
1133
1134 *child_flags = flags;
1135}
1136
1137static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
1138 const char *filename, Error **errp)
1139{
1140 BlockDriverState *parent = c->opaque;
1141 bool read_only = bdrv_is_read_only(parent);
1142 int ret;
1143
1144 if (read_only) {
1145 ret = bdrv_reopen_set_read_only(parent, false, errp);
1146 if (ret < 0) {
1147 return ret;
1148 }
1149 }
1150
1151 ret = bdrv_change_backing_file(parent, filename,
1152 base->drv ? base->drv->format_name : "");
1153 if (ret < 0) {
1154 error_setg_errno(errp, -ret, "Could not update backing file link");
1155 }
1156
1157 if (read_only) {
1158 bdrv_reopen_set_read_only(parent, true, NULL);
1159 }
1160
1161 return ret;
1162}
1163
1164const BdrvChildRole child_backing = {
1165 .parent_is_bds = true,
1166 .get_parent_desc = bdrv_child_get_parent_desc,
1167 .attach = bdrv_backing_attach,
1168 .detach = bdrv_backing_detach,
1169 .inherit_options = bdrv_backing_options,
1170 .drained_begin = bdrv_child_cb_drained_begin,
1171 .drained_poll = bdrv_child_cb_drained_poll,
1172 .drained_end = bdrv_child_cb_drained_end,
1173 .inactivate = bdrv_child_cb_inactivate,
1174 .update_filename = bdrv_backing_update_filename,
1175 .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx,
1176 .set_aio_ctx = bdrv_child_cb_set_aio_ctx,
1177};
1178
1179static int bdrv_open_flags(BlockDriverState *bs, int flags)
1180{
1181 int open_flags = flags;
1182
1183 /*
1184 * Clear flags that are internal to the block layer before opening the
1185 * image.
1186 */
1187 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL);
1188
1189 return open_flags;
1190}
1191
1192static void update_flags_from_options(int *flags, QemuOpts *opts)
1193{
1194 *flags &= ~(BDRV_O_CACHE_MASK | BDRV_O_RDWR | BDRV_O_AUTO_RDONLY);
1195
1196 if (qemu_opt_get_bool_del(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
1197 *flags |= BDRV_O_NO_FLUSH;
1198 }
1199
1200 if (qemu_opt_get_bool_del(opts, BDRV_OPT_CACHE_DIRECT, false)) {
1201 *flags |= BDRV_O_NOCACHE;
1202 }
1203
1204 if (!qemu_opt_get_bool_del(opts, BDRV_OPT_READ_ONLY, false)) {
1205 *flags |= BDRV_O_RDWR;
1206 }
1207
1208 if (qemu_opt_get_bool_del(opts, BDRV_OPT_AUTO_READ_ONLY, false)) {
1209 *flags |= BDRV_O_AUTO_RDONLY;
1210 }
1211}
1212
1213static void update_options_from_flags(QDict *options, int flags)
1214{
1215 if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) {
1216 qdict_put_bool(options, BDRV_OPT_CACHE_DIRECT, flags & BDRV_O_NOCACHE);
1217 }
1218 if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) {
1219 qdict_put_bool(options, BDRV_OPT_CACHE_NO_FLUSH,
1220 flags & BDRV_O_NO_FLUSH);
1221 }
1222 if (!qdict_haskey(options, BDRV_OPT_READ_ONLY)) {
1223 qdict_put_bool(options, BDRV_OPT_READ_ONLY, !(flags & BDRV_O_RDWR));
1224 }
1225 if (!qdict_haskey(options, BDRV_OPT_AUTO_READ_ONLY)) {
1226 qdict_put_bool(options, BDRV_OPT_AUTO_READ_ONLY,
1227 flags & BDRV_O_AUTO_RDONLY);
1228 }
1229}
1230
1231static void bdrv_assign_node_name(BlockDriverState *bs,
1232 const char *node_name,
1233 Error **errp)
1234{
1235 char *gen_node_name = NULL;
1236
1237 if (!node_name) {
1238 node_name = gen_node_name = id_generate(ID_BLOCK);
1239 } else if (!id_wellformed(node_name)) {
1240 /*
1241 * Check for empty string or invalid characters, but not if it is
1242 * generated (generated names use characters not available to the user)
1243 */
1244 error_setg(errp, "Invalid node name");
1245 return;
1246 }
1247
1248 /* takes care of avoiding namespaces collisions */
1249 if (blk_by_name(node_name)) {
1250 error_setg(errp, "node-name=%s is conflicting with a device id",
1251 node_name);
1252 goto out;
1253 }
1254
1255 /* takes care of avoiding duplicates node names */
1256 if (bdrv_find_node(node_name)) {
1257 error_setg(errp, "Duplicate node name");
1258 goto out;
1259 }
1260
1261 /* Make sure that the node name isn't truncated */
1262 if (strlen(node_name) >= sizeof(bs->node_name)) {
1263 error_setg(errp, "Node name too long");
1264 goto out;
1265 }
1266
1267 /* copy node name into the bs and insert it into the graph list */
1268 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
1269 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
1270out:
1271 g_free(gen_node_name);
1272}
1273
1274static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv,
1275 const char *node_name, QDict *options,
1276 int open_flags, Error **errp)
1277{
1278 Error *local_err = NULL;
1279 int i, ret;
1280
1281 bdrv_assign_node_name(bs, node_name, &local_err);
1282 if (local_err) {
1283 error_propagate(errp, local_err);
1284 return -EINVAL;
1285 }
1286
1287 bs->drv = drv;
1288 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
1289 bs->opaque = g_malloc0(drv->instance_size);
1290
1291 if (drv->bdrv_file_open) {
1292 assert(!drv->bdrv_needs_filename || bs->filename[0]);
1293 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err);
1294 } else if (drv->bdrv_open) {
1295 ret = drv->bdrv_open(bs, options, open_flags, &local_err);
1296 } else {
1297 ret = 0;
1298 }
1299
1300 if (ret < 0) {
1301 if (local_err) {
1302 error_propagate(errp, local_err);
1303 } else if (bs->filename[0]) {
1304 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename);
1305 } else {
1306 error_setg_errno(errp, -ret, "Could not open image");
1307 }
1308 goto open_failed;
1309 }
1310
1311 ret = refresh_total_sectors(bs, bs->total_sectors);
1312 if (ret < 0) {
1313 error_setg_errno(errp, -ret, "Could not refresh total sector count");
1314 return ret;
1315 }
1316
1317 bdrv_refresh_limits(bs, &local_err);
1318 if (local_err) {
1319 error_propagate(errp, local_err);
1320 return -EINVAL;
1321 }
1322
1323 assert(bdrv_opt_mem_align(bs) != 0);
1324 assert(bdrv_min_mem_align(bs) != 0);
1325 assert(is_power_of_2(bs->bl.request_alignment));
1326
1327 for (i = 0; i < bs->quiesce_counter; i++) {
1328 if (drv->bdrv_co_drain_begin) {
1329 drv->bdrv_co_drain_begin(bs);
1330 }
1331 }
1332
1333 return 0;
1334open_failed:
1335 bs->drv = NULL;
1336 if (bs->file != NULL) {
1337 bdrv_unref_child(bs, bs->file);
1338 bs->file = NULL;
1339 }
1340 g_free(bs->opaque);
1341 bs->opaque = NULL;
1342 return ret;
1343}
1344
1345BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
1346 int flags, Error **errp)
1347{
1348 BlockDriverState *bs;
1349 int ret;
1350
1351 bs = bdrv_new();
1352 bs->open_flags = flags;
1353 bs->explicit_options = qdict_new();
1354 bs->options = qdict_new();
1355 bs->opaque = NULL;
1356
1357 update_options_from_flags(bs->options, flags);
1358
1359 ret = bdrv_open_driver(bs, drv, node_name, bs->options, flags, errp);
1360 if (ret < 0) {
1361 qobject_unref(bs->explicit_options);
1362 bs->explicit_options = NULL;
1363 qobject_unref(bs->options);
1364 bs->options = NULL;
1365 bdrv_unref(bs);
1366 return NULL;
1367 }
1368
1369 return bs;
1370}
1371
1372QemuOptsList bdrv_runtime_opts = {
1373 .name = "bdrv_common",
1374 .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head),
1375 .desc = {
1376 {
1377 .name = "node-name",
1378 .type = QEMU_OPT_STRING,
1379 .help = "Node name of the block device node",
1380 },
1381 {
1382 .name = "driver",
1383 .type = QEMU_OPT_STRING,
1384 .help = "Block driver to use for the node",
1385 },
1386 {
1387 .name = BDRV_OPT_CACHE_DIRECT,
1388 .type = QEMU_OPT_BOOL,
1389 .help = "Bypass software writeback cache on the host",
1390 },
1391 {
1392 .name = BDRV_OPT_CACHE_NO_FLUSH,
1393 .type = QEMU_OPT_BOOL,
1394 .help = "Ignore flush requests",
1395 },
1396 {
1397 .name = BDRV_OPT_READ_ONLY,
1398 .type = QEMU_OPT_BOOL,
1399 .help = "Node is opened in read-only mode",
1400 },
1401 {
1402 .name = BDRV_OPT_AUTO_READ_ONLY,
1403 .type = QEMU_OPT_BOOL,
1404 .help = "Node can become read-only if opening read-write fails",
1405 },
1406 {
1407 .name = "detect-zeroes",
1408 .type = QEMU_OPT_STRING,
1409 .help = "try to optimize zero writes (off, on, unmap)",
1410 },
1411 {
1412 .name = BDRV_OPT_DISCARD,
1413 .type = QEMU_OPT_STRING,
1414 .help = "discard operation (ignore/off, unmap/on)",
1415 },
1416 {
1417 .name = BDRV_OPT_FORCE_SHARE,
1418 .type = QEMU_OPT_BOOL,
1419 .help = "always accept other writers (default: off)",
1420 },
1421 { /* end of list */ }
1422 },
1423};
1424
1425/*
1426 * Common part for opening disk images and files
1427 *
1428 * Removes all processed options from *options.
1429 */
1430static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file,
1431 QDict *options, Error **errp)
1432{
1433 int ret, open_flags;
1434 const char *filename;
1435 const char *driver_name = NULL;
1436 const char *node_name = NULL;
1437 const char *discard;
1438 QemuOpts *opts;
1439 BlockDriver *drv;
1440 Error *local_err = NULL;
1441
1442 assert(bs->file == NULL);
1443 assert(options != NULL && bs->options != options);
1444
1445 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
1446 qemu_opts_absorb_qdict(opts, options, &local_err);
1447 if (local_err) {
1448 error_propagate(errp, local_err);
1449 ret = -EINVAL;
1450 goto fail_opts;
1451 }
1452
1453 update_flags_from_options(&bs->open_flags, opts);
1454
1455 driver_name = qemu_opt_get(opts, "driver");
1456 drv = bdrv_find_format(driver_name);
1457 assert(drv != NULL);
1458
1459 bs->force_share = qemu_opt_get_bool(opts, BDRV_OPT_FORCE_SHARE, false);
1460
1461 if (bs->force_share && (bs->open_flags & BDRV_O_RDWR)) {
1462 error_setg(errp,
1463 BDRV_OPT_FORCE_SHARE
1464 "=on can only be used with read-only images");
1465 ret = -EINVAL;
1466 goto fail_opts;
1467 }
1468
1469 if (file != NULL) {
1470 bdrv_refresh_filename(blk_bs(file));
1471 filename = blk_bs(file)->filename;
1472 } else {
1473 /*
1474 * Caution: while qdict_get_try_str() is fine, getting
1475 * non-string types would require more care. When @options
1476 * come from -blockdev or blockdev_add, its members are typed
1477 * according to the QAPI schema, but when they come from
1478 * -drive, they're all QString.
1479 */
1480 filename = qdict_get_try_str(options, "filename");
1481 }
1482
1483 if (drv->bdrv_needs_filename && (!filename || !filename[0])) {
1484 error_setg(errp, "The '%s' block driver requires a file name",
1485 drv->format_name);
1486 ret = -EINVAL;
1487 goto fail_opts;
1488 }
1489
1490 trace_bdrv_open_common(bs, filename ?: "", bs->open_flags,
1491 drv->format_name);
1492
1493 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
1494
1495 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
1496 if (!bs->read_only && bdrv_is_whitelisted(drv, true)) {
1497 ret = bdrv_apply_auto_read_only(bs, NULL, NULL);
1498 } else {
1499 ret = -ENOTSUP;
1500 }
1501 if (ret < 0) {
1502 error_setg(errp,
1503 !bs->read_only && bdrv_is_whitelisted(drv, true)
1504 ? "Driver '%s' can only be used for read-only devices"
1505 : "Driver '%s' is not whitelisted",
1506 drv->format_name);
1507 goto fail_opts;
1508 }
1509 }
1510
1511 /* bdrv_new() and bdrv_close() make it so */
1512 assert(atomic_read(&bs->copy_on_read) == 0);
1513
1514 if (bs->open_flags & BDRV_O_COPY_ON_READ) {
1515 if (!bs->read_only) {
1516 bdrv_enable_copy_on_read(bs);
1517 } else {
1518 error_setg(errp, "Can't use copy-on-read on read-only device");
1519 ret = -EINVAL;
1520 goto fail_opts;
1521 }
1522 }
1523
1524 discard = qemu_opt_get(opts, BDRV_OPT_DISCARD);
1525 if (discard != NULL) {
1526 if (bdrv_parse_discard_flags(discard, &bs->open_flags) != 0) {
1527 error_setg(errp, "Invalid discard option");
1528 ret = -EINVAL;
1529 goto fail_opts;
1530 }
1531 }
1532
1533 bs->detect_zeroes =
1534 bdrv_parse_detect_zeroes(opts, bs->open_flags, &local_err);
1535 if (local_err) {
1536 error_propagate(errp, local_err);
1537 ret = -EINVAL;
1538 goto fail_opts;
1539 }
1540
1541 if (filename != NULL) {
1542 pstrcpy(bs->filename, sizeof(bs->filename), filename);
1543 } else {
1544 bs->filename[0] = '\0';
1545 }
1546 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename);
1547
1548 /* Open the image, either directly or using a protocol */
1549 open_flags = bdrv_open_flags(bs, bs->open_flags);
1550 node_name = qemu_opt_get(opts, "node-name");
1551
1552 assert(!drv->bdrv_file_open || file == NULL);
1553 ret = bdrv_open_driver(bs, drv, node_name, options, open_flags, errp);
1554 if (ret < 0) {
1555 goto fail_opts;
1556 }
1557
1558 qemu_opts_del(opts);
1559 return 0;
1560
1561fail_opts:
1562 qemu_opts_del(opts);
1563 return ret;
1564}
1565
1566static QDict *parse_json_filename(const char *filename, Error **errp)
1567{
1568 QObject *options_obj;
1569 QDict *options;
1570 int ret;
1571
1572 ret = strstart(filename, "json:", &filename);
1573 assert(ret);
1574
1575 options_obj = qobject_from_json(filename, errp);
1576 if (!options_obj) {
1577 error_prepend(errp, "Could not parse the JSON options: ");
1578 return NULL;
1579 }
1580
1581 options = qobject_to(QDict, options_obj);
1582 if (!options) {
1583 qobject_unref(options_obj);
1584 error_setg(errp, "Invalid JSON object given");
1585 return NULL;
1586 }
1587
1588 qdict_flatten(options);
1589
1590 return options;
1591}
1592
1593static void parse_json_protocol(QDict *options, const char **pfilename,
1594 Error **errp)
1595{
1596 QDict *json_options;
1597 Error *local_err = NULL;
1598
1599 /* Parse json: pseudo-protocol */
1600 if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) {
1601 return;
1602 }
1603
1604 json_options = parse_json_filename(*pfilename, &local_err);
1605 if (local_err) {
1606 error_propagate(errp, local_err);
1607 return;
1608 }
1609
1610 /* Options given in the filename have lower priority than options
1611 * specified directly */
1612 qdict_join(options, json_options, false);
1613 qobject_unref(json_options);
1614 *pfilename = NULL;
1615}
1616
1617/*
1618 * Fills in default options for opening images and converts the legacy
1619 * filename/flags pair to option QDict entries.
1620 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1621 * block driver has been specified explicitly.
1622 */
1623static int bdrv_fill_options(QDict **options, const char *filename,
1624 int *flags, Error **errp)
1625{
1626 const char *drvname;
1627 bool protocol = *flags & BDRV_O_PROTOCOL;
1628 bool parse_filename = false;
1629 BlockDriver *drv = NULL;
1630 Error *local_err = NULL;
1631
1632 /*
1633 * Caution: while qdict_get_try_str() is fine, getting non-string
1634 * types would require more care. When @options come from
1635 * -blockdev or blockdev_add, its members are typed according to
1636 * the QAPI schema, but when they come from -drive, they're all
1637 * QString.
1638 */
1639 drvname = qdict_get_try_str(*options, "driver");
1640 if (drvname) {
1641 drv = bdrv_find_format(drvname);
1642 if (!drv) {
1643 error_setg(errp, "Unknown driver '%s'", drvname);
1644 return -ENOENT;
1645 }
1646 /* If the user has explicitly specified the driver, this choice should
1647 * override the BDRV_O_PROTOCOL flag */
1648 protocol = drv->bdrv_file_open;
1649 }
1650
1651 if (protocol) {
1652 *flags |= BDRV_O_PROTOCOL;
1653 } else {
1654 *flags &= ~BDRV_O_PROTOCOL;
1655 }
1656
1657 /* Translate cache options from flags into options */
1658 update_options_from_flags(*options, *flags);
1659
1660 /* Fetch the file name from the options QDict if necessary */
1661 if (protocol && filename) {
1662 if (!qdict_haskey(*options, "filename")) {
1663 qdict_put_str(*options, "filename", filename);
1664 parse_filename = true;
1665 } else {
1666 error_setg(errp, "Can't specify 'file' and 'filename' options at "
1667 "the same time");
1668 return -EINVAL;
1669 }
1670 }
1671
1672 /* Find the right block driver */
1673 /* See cautionary note on accessing @options above */
1674 filename = qdict_get_try_str(*options, "filename");
1675
1676 if (!drvname && protocol) {
1677 if (filename) {
1678 drv = bdrv_find_protocol(filename, parse_filename, errp);
1679 if (!drv) {
1680 return -EINVAL;
1681 }
1682
1683 drvname = drv->format_name;
1684 qdict_put_str(*options, "driver", drvname);
1685 } else {
1686 error_setg(errp, "Must specify either driver or file");
1687 return -EINVAL;
1688 }
1689 }
1690
1691 assert(drv || !protocol);
1692
1693 /* Driver-specific filename parsing */
1694 if (drv && drv->bdrv_parse_filename && parse_filename) {
1695 drv->bdrv_parse_filename(filename, *options, &local_err);
1696 if (local_err) {
1697 error_propagate(errp, local_err);
1698 return -EINVAL;
1699 }
1700
1701 if (!drv->bdrv_needs_filename) {
1702 qdict_del(*options, "filename");
1703 }
1704 }
1705
1706 return 0;
1707}
1708
1709static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q,
1710 uint64_t perm, uint64_t shared,
1711 GSList *ignore_children,
1712 bool *tighten_restrictions, Error **errp);
1713static void bdrv_child_abort_perm_update(BdrvChild *c);
1714static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared);
1715static void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm,
1716 uint64_t *shared_perm);
1717
1718typedef struct BlockReopenQueueEntry {
1719 bool prepared;
1720 bool perms_checked;
1721 BDRVReopenState state;
1722 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry;
1723} BlockReopenQueueEntry;
1724
1725/*
1726 * Return the flags that @bs will have after the reopens in @q have
1727 * successfully completed. If @q is NULL (or @bs is not contained in @q),
1728 * return the current flags.
1729 */
1730static int bdrv_reopen_get_flags(BlockReopenQueue *q, BlockDriverState *bs)
1731{
1732 BlockReopenQueueEntry *entry;
1733
1734 if (q != NULL) {
1735 QSIMPLEQ_FOREACH(entry, q, entry) {
1736 if (entry->state.bs == bs) {
1737 return entry->state.flags;
1738 }
1739 }
1740 }
1741
1742 return bs->open_flags;
1743}
1744
1745/* Returns whether the image file can be written to after the reopen queue @q
1746 * has been successfully applied, or right now if @q is NULL. */
1747static bool bdrv_is_writable_after_reopen(BlockDriverState *bs,
1748 BlockReopenQueue *q)
1749{
1750 int flags = bdrv_reopen_get_flags(q, bs);
1751
1752 return (flags & (BDRV_O_RDWR | BDRV_O_INACTIVE)) == BDRV_O_RDWR;
1753}
1754
1755/*
1756 * Return whether the BDS can be written to. This is not necessarily
1757 * the same as !bdrv_is_read_only(bs), as inactivated images may not
1758 * be written to but do not count as read-only images.
1759 */
1760bool bdrv_is_writable(BlockDriverState *bs)
1761{
1762 return bdrv_is_writable_after_reopen(bs, NULL);
1763}
1764
1765static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs,
1766 BdrvChild *c, const BdrvChildRole *role,
1767 BlockReopenQueue *reopen_queue,
1768 uint64_t parent_perm, uint64_t parent_shared,
1769 uint64_t *nperm, uint64_t *nshared)
1770{
1771 assert(bs->drv && bs->drv->bdrv_child_perm);
1772 bs->drv->bdrv_child_perm(bs, c, role, reopen_queue,
1773 parent_perm, parent_shared,
1774 nperm, nshared);
1775 /* TODO Take force_share from reopen_queue */
1776 if (child_bs && child_bs->force_share) {
1777 *nshared = BLK_PERM_ALL;
1778 }
1779}
1780
1781/*
1782 * Check whether permissions on this node can be changed in a way that
1783 * @cumulative_perms and @cumulative_shared_perms are the new cumulative
1784 * permissions of all its parents. This involves checking whether all necessary
1785 * permission changes to child nodes can be performed.
1786 *
1787 * Will set *tighten_restrictions to true if and only if new permissions have to
1788 * be taken or currently shared permissions are to be unshared. Otherwise,
1789 * errors are not fatal as long as the caller accepts that the restrictions
1790 * remain tighter than they need to be. The caller still has to abort the
1791 * transaction.
1792 * @tighten_restrictions cannot be used together with @q: When reopening, we may
1793 * encounter fatal errors even though no restrictions are to be tightened. For
1794 * example, changing a node from RW to RO will fail if the WRITE permission is
1795 * to be kept.
1796 *
1797 * A call to this function must always be followed by a call to bdrv_set_perm()
1798 * or bdrv_abort_perm_update().
1799 */
1800static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
1801 uint64_t cumulative_perms,
1802 uint64_t cumulative_shared_perms,
1803 GSList *ignore_children,
1804 bool *tighten_restrictions, Error **errp)
1805{
1806 BlockDriver *drv = bs->drv;
1807 BdrvChild *c;
1808 int ret;
1809
1810 assert(!q || !tighten_restrictions);
1811
1812 if (tighten_restrictions) {
1813 uint64_t current_perms, current_shared;
1814 uint64_t added_perms, removed_shared_perms;
1815
1816 bdrv_get_cumulative_perm(bs, &current_perms, &current_shared);
1817
1818 added_perms = cumulative_perms & ~current_perms;
1819 removed_shared_perms = current_shared & ~cumulative_shared_perms;
1820
1821 *tighten_restrictions = added_perms || removed_shared_perms;
1822 }
1823
1824 /* Write permissions never work with read-only images */
1825 if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) &&
1826 !bdrv_is_writable_after_reopen(bs, q))
1827 {
1828 if (!bdrv_is_writable_after_reopen(bs, NULL)) {
1829 error_setg(errp, "Block node is read-only");
1830 } else {
1831 uint64_t current_perms, current_shared;
1832 bdrv_get_cumulative_perm(bs, &current_perms, &current_shared);
1833 if (current_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) {
1834 error_setg(errp, "Cannot make block node read-only, there is "
1835 "a writer on it");
1836 } else {
1837 error_setg(errp, "Cannot make block node read-only and create "
1838 "a writer on it");
1839 }
1840 }
1841
1842 return -EPERM;
1843 }
1844
1845 /* Check this node */
1846 if (!drv) {
1847 return 0;
1848 }
1849
1850 if (drv->bdrv_check_perm) {
1851 return drv->bdrv_check_perm(bs, cumulative_perms,
1852 cumulative_shared_perms, errp);
1853 }
1854
1855 /* Drivers that never have children can omit .bdrv_child_perm() */
1856 if (!drv->bdrv_child_perm) {
1857 assert(QLIST_EMPTY(&bs->children));
1858 return 0;
1859 }
1860
1861 /* Check all children */
1862 QLIST_FOREACH(c, &bs->children, next) {
1863 uint64_t cur_perm, cur_shared;
1864 bool child_tighten_restr;
1865
1866 bdrv_child_perm(bs, c->bs, c, c->role, q,
1867 cumulative_perms, cumulative_shared_perms,
1868 &cur_perm, &cur_shared);
1869 ret = bdrv_child_check_perm(c, q, cur_perm, cur_shared, ignore_children,
1870 tighten_restrictions ? &child_tighten_restr
1871 : NULL,
1872 errp);
1873 if (tighten_restrictions) {
1874 *tighten_restrictions |= child_tighten_restr;
1875 }
1876 if (ret < 0) {
1877 return ret;
1878 }
1879 }
1880
1881 return 0;
1882}
1883
1884/*
1885 * Notifies drivers that after a previous bdrv_check_perm() call, the
1886 * permission update is not performed and any preparations made for it (e.g.
1887 * taken file locks) need to be undone.
1888 *
1889 * This function recursively notifies all child nodes.
1890 */
1891static void bdrv_abort_perm_update(BlockDriverState *bs)
1892{
1893 BlockDriver *drv = bs->drv;
1894 BdrvChild *c;
1895
1896 if (!drv) {
1897 return;
1898 }
1899
1900 if (drv->bdrv_abort_perm_update) {
1901 drv->bdrv_abort_perm_update(bs);
1902 }
1903
1904 QLIST_FOREACH(c, &bs->children, next) {
1905 bdrv_child_abort_perm_update(c);
1906 }
1907}
1908
1909static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms,
1910 uint64_t cumulative_shared_perms)
1911{
1912 BlockDriver *drv = bs->drv;
1913 BdrvChild *c;
1914
1915 if (!drv) {
1916 return;
1917 }
1918
1919 /* Update this node */
1920 if (drv->bdrv_set_perm) {
1921 drv->bdrv_set_perm(bs, cumulative_perms, cumulative_shared_perms);
1922 }
1923
1924 /* Drivers that never have children can omit .bdrv_child_perm() */
1925 if (!drv->bdrv_child_perm) {
1926 assert(QLIST_EMPTY(&bs->children));
1927 return;
1928 }
1929
1930 /* Update all children */
1931 QLIST_FOREACH(c, &bs->children, next) {
1932 uint64_t cur_perm, cur_shared;
1933 bdrv_child_perm(bs, c->bs, c, c->role, NULL,
1934 cumulative_perms, cumulative_shared_perms,
1935 &cur_perm, &cur_shared);
1936 bdrv_child_set_perm(c, cur_perm, cur_shared);
1937 }
1938}
1939
1940static void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm,
1941 uint64_t *shared_perm)
1942{
1943 BdrvChild *c;
1944 uint64_t cumulative_perms = 0;
1945 uint64_t cumulative_shared_perms = BLK_PERM_ALL;
1946
1947 QLIST_FOREACH(c, &bs->parents, next_parent) {
1948 cumulative_perms |= c->perm;
1949 cumulative_shared_perms &= c->shared_perm;
1950 }
1951
1952 *perm = cumulative_perms;
1953 *shared_perm = cumulative_shared_perms;
1954}
1955
1956static char *bdrv_child_user_desc(BdrvChild *c)
1957{
1958 if (c->role->get_parent_desc) {
1959 return c->role->get_parent_desc(c);
1960 }
1961
1962 return g_strdup("another user");
1963}
1964
1965char *bdrv_perm_names(uint64_t perm)
1966{
1967 struct perm_name {
1968 uint64_t perm;
1969 const char *name;
1970 } permissions[] = {
1971 { BLK_PERM_CONSISTENT_READ, "consistent read" },
1972 { BLK_PERM_WRITE, "write" },
1973 { BLK_PERM_WRITE_UNCHANGED, "write unchanged" },
1974 { BLK_PERM_RESIZE, "resize" },
1975 { BLK_PERM_GRAPH_MOD, "change children" },
1976 { 0, NULL }
1977 };
1978
1979 char *result = g_strdup("");
1980 struct perm_name *p;
1981
1982 for (p = permissions; p->name; p++) {
1983 if (perm & p->perm) {
1984 char *old = result;
1985 result = g_strdup_printf("%s%s%s", old, *old ? ", " : "", p->name);
1986 g_free(old);
1987 }
1988 }
1989
1990 return result;
1991}
1992
1993/*
1994 * Checks whether a new reference to @bs can be added if the new user requires
1995 * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is
1996 * set, the BdrvChild objects in this list are ignored in the calculations;
1997 * this allows checking permission updates for an existing reference.
1998 *
1999 * See bdrv_check_perm() for the semantics of @tighten_restrictions.
2000 *
2001 * Needs to be followed by a call to either bdrv_set_perm() or
2002 * bdrv_abort_perm_update(). */
2003static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q,
2004 uint64_t new_used_perm,
2005 uint64_t new_shared_perm,
2006 GSList *ignore_children,
2007 bool *tighten_restrictions,
2008 Error **errp)
2009{
2010 BdrvChild *c;
2011 uint64_t cumulative_perms = new_used_perm;
2012 uint64_t cumulative_shared_perms = new_shared_perm;
2013
2014 assert(!q || !tighten_restrictions);
2015
2016 /* There is no reason why anyone couldn't tolerate write_unchanged */
2017 assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED);
2018
2019 QLIST_FOREACH(c, &bs->parents, next_parent) {
2020 if (g_slist_find(ignore_children, c)) {
2021 continue;
2022 }
2023
2024 if ((new_used_perm & c->shared_perm) != new_used_perm) {
2025 char *user = bdrv_child_user_desc(c);
2026 char *perm_names = bdrv_perm_names(new_used_perm & ~c->shared_perm);
2027
2028 if (tighten_restrictions) {
2029 *tighten_restrictions = true;
2030 }
2031
2032 error_setg(errp, "Conflicts with use by %s as '%s', which does not "
2033 "allow '%s' on %s",
2034 user, c->name, perm_names, bdrv_get_node_name(c->bs));
2035 g_free(user);
2036 g_free(perm_names);
2037 return -EPERM;
2038 }
2039
2040 if ((c->perm & new_shared_perm) != c->perm) {
2041 char *user = bdrv_child_user_desc(c);
2042 char *perm_names = bdrv_perm_names(c->perm & ~new_shared_perm);
2043
2044 if (tighten_restrictions) {
2045 *tighten_restrictions = true;
2046 }
2047
2048 error_setg(errp, "Conflicts with use by %s as '%s', which uses "
2049 "'%s' on %s",
2050 user, c->name, perm_names, bdrv_get_node_name(c->bs));
2051 g_free(user);
2052 g_free(perm_names);
2053 return -EPERM;
2054 }
2055
2056 cumulative_perms |= c->perm;
2057 cumulative_shared_perms &= c->shared_perm;
2058 }
2059
2060 return bdrv_check_perm(bs, q, cumulative_perms, cumulative_shared_perms,
2061 ignore_children, tighten_restrictions, errp);
2062}
2063
2064/* Needs to be followed by a call to either bdrv_child_set_perm() or
2065 * bdrv_child_abort_perm_update(). */
2066static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q,
2067 uint64_t perm, uint64_t shared,
2068 GSList *ignore_children,
2069 bool *tighten_restrictions, Error **errp)
2070{
2071 int ret;
2072
2073 ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c);
2074 ret = bdrv_check_update_perm(c->bs, q, perm, shared, ignore_children,
2075 tighten_restrictions, errp);
2076 g_slist_free(ignore_children);
2077
2078 if (ret < 0) {
2079 return ret;
2080 }
2081
2082 if (!c->has_backup_perm) {
2083 c->has_backup_perm = true;
2084 c->backup_perm = c->perm;
2085 c->backup_shared_perm = c->shared_perm;
2086 }
2087 /*
2088 * Note: it's OK if c->has_backup_perm was already set, as we can find the
2089 * same child twice during check_perm procedure
2090 */
2091
2092 c->perm = perm;
2093 c->shared_perm = shared;
2094
2095 return 0;
2096}
2097
2098static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared)
2099{
2100 uint64_t cumulative_perms, cumulative_shared_perms;
2101
2102 c->has_backup_perm = false;
2103
2104 c->perm = perm;
2105 c->shared_perm = shared;
2106
2107 bdrv_get_cumulative_perm(c->bs, &cumulative_perms,
2108 &cumulative_shared_perms);
2109 bdrv_set_perm(c->bs, cumulative_perms, cumulative_shared_perms);
2110}
2111
2112static void bdrv_child_abort_perm_update(BdrvChild *c)
2113{
2114 if (c->has_backup_perm) {
2115 c->perm = c->backup_perm;
2116 c->shared_perm = c->backup_shared_perm;
2117 c->has_backup_perm = false;
2118 }
2119
2120 bdrv_abort_perm_update(c->bs);
2121}
2122
2123int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
2124 Error **errp)
2125{
2126 Error *local_err = NULL;
2127 int ret;
2128 bool tighten_restrictions;
2129
2130 ret = bdrv_child_check_perm(c, NULL, perm, shared, NULL,
2131 &tighten_restrictions, &local_err);
2132 if (ret < 0) {
2133 bdrv_child_abort_perm_update(c);
2134 if (tighten_restrictions) {
2135 error_propagate(errp, local_err);
2136 } else {
2137 /*
2138 * Our caller may intend to only loosen restrictions and
2139 * does not expect this function to fail. Errors are not
2140 * fatal in such a case, so we can just hide them from our
2141 * caller.
2142 */
2143 error_free(local_err);
2144 ret = 0;
2145 }
2146 return ret;
2147 }
2148
2149 bdrv_child_set_perm(c, perm, shared);
2150
2151 return 0;
2152}
2153
2154int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp)
2155{
2156 uint64_t parent_perms, parent_shared;
2157 uint64_t perms, shared;
2158
2159 bdrv_get_cumulative_perm(bs, &parent_perms, &parent_shared);
2160 bdrv_child_perm(bs, c->bs, c, c->role, NULL, parent_perms, parent_shared,
2161 &perms, &shared);
2162
2163 return bdrv_child_try_set_perm(c, perms, shared, errp);
2164}
2165
2166void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
2167 const BdrvChildRole *role,
2168 BlockReopenQueue *reopen_queue,
2169 uint64_t perm, uint64_t shared,
2170 uint64_t *nperm, uint64_t *nshared)
2171{
2172 *nperm = perm & DEFAULT_PERM_PASSTHROUGH;
2173 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
2174}
2175
2176void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
2177 const BdrvChildRole *role,
2178 BlockReopenQueue *reopen_queue,
2179 uint64_t perm, uint64_t shared,
2180 uint64_t *nperm, uint64_t *nshared)
2181{
2182 bool backing = (role == &child_backing);
2183 assert(role == &child_backing || role == &child_file);
2184
2185 if (!backing) {
2186 int flags = bdrv_reopen_get_flags(reopen_queue, bs);
2187
2188 /* Apart from the modifications below, the same permissions are
2189 * forwarded and left alone as for filters */
2190 bdrv_filter_default_perms(bs, c, role, reopen_queue, perm, shared,
2191 &perm, &shared);
2192
2193 /* Format drivers may touch metadata even if the guest doesn't write */
2194 if (bdrv_is_writable_after_reopen(bs, reopen_queue)) {
2195 perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
2196 }
2197
2198 /* bs->file always needs to be consistent because of the metadata. We
2199 * can never allow other users to resize or write to it. */
2200 if (!(flags & BDRV_O_NO_IO)) {
2201 perm |= BLK_PERM_CONSISTENT_READ;
2202 }
2203 shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
2204 } else {
2205 /* We want consistent read from backing files if the parent needs it.
2206 * No other operations are performed on backing files. */
2207 perm &= BLK_PERM_CONSISTENT_READ;
2208
2209 /* If the parent can deal with changing data, we're okay with a
2210 * writable and resizable backing file. */
2211 /* TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? */
2212 if (shared & BLK_PERM_WRITE) {
2213 shared = BLK_PERM_WRITE | BLK_PERM_RESIZE;
2214 } else {
2215 shared = 0;
2216 }
2217
2218 shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD |
2219 BLK_PERM_WRITE_UNCHANGED;
2220 }
2221
2222 if (bs->open_flags & BDRV_O_INACTIVE) {
2223 shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
2224 }
2225
2226 *nperm = perm;
2227 *nshared = shared;
2228}
2229
2230static void bdrv_replace_child_noperm(BdrvChild *child,
2231 BlockDriverState *new_bs)
2232{
2233 BlockDriverState *old_bs = child->bs;
2234 int new_bs_quiesce_counter;
2235 int drain_saldo;
2236
2237 assert(!child->frozen);
2238
2239 if (old_bs && new_bs) {
2240 assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs));
2241 }
2242
2243 new_bs_quiesce_counter = (new_bs ? new_bs->quiesce_counter : 0);
2244 drain_saldo = new_bs_quiesce_counter - child->parent_quiesce_counter;
2245
2246 /*
2247 * If the new child node is drained but the old one was not, flush
2248 * all outstanding requests to the old child node.
2249 */
2250 while (drain_saldo > 0 && child->role->drained_begin) {
2251 bdrv_parent_drained_begin_single(child, true);
2252 drain_saldo--;
2253 }
2254
2255 if (old_bs) {
2256 /* Detach first so that the recursive drain sections coming from @child
2257 * are already gone and we only end the drain sections that came from
2258 * elsewhere. */
2259 if (child->role->detach) {
2260 child->role->detach(child);
2261 }
2262 QLIST_REMOVE(child, next_parent);
2263 }
2264
2265 child->bs = new_bs;
2266
2267 if (new_bs) {
2268 QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
2269
2270 /*
2271 * Detaching the old node may have led to the new node's
2272 * quiesce_counter having been decreased. Not a problem, we
2273 * just need to recognize this here and then invoke
2274 * drained_end appropriately more often.
2275 */
2276 assert(new_bs->quiesce_counter <= new_bs_quiesce_counter);
2277 drain_saldo += new_bs->quiesce_counter - new_bs_quiesce_counter;
2278
2279 /* Attach only after starting new drained sections, so that recursive
2280 * drain sections coming from @child don't get an extra .drained_begin
2281 * callback. */
2282 if (child->role->attach) {
2283 child->role->attach(child);
2284 }
2285 }
2286
2287 /*
2288 * If the old child node was drained but the new one is not, allow
2289 * requests to come in only after the new node has been attached.
2290 */
2291 while (drain_saldo < 0 && child->role->drained_end) {
2292 bdrv_parent_drained_end_single(child);
2293 drain_saldo++;
2294 }
2295}
2296
2297/*
2298 * Updates @child to change its reference to point to @new_bs, including
2299 * checking and applying the necessary permisson updates both to the old node
2300 * and to @new_bs.
2301 *
2302 * NULL is passed as @new_bs for removing the reference before freeing @child.
2303 *
2304 * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this
2305 * function uses bdrv_set_perm() to update the permissions according to the new
2306 * reference that @new_bs gets.
2307 */
2308static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
2309{
2310 BlockDriverState *old_bs = child->bs;
2311 uint64_t perm, shared_perm;
2312
2313 bdrv_replace_child_noperm(child, new_bs);
2314
2315 /*
2316 * Start with the new node's permissions. If @new_bs is a (direct
2317 * or indirect) child of @old_bs, we must complete the permission
2318 * update on @new_bs before we loosen the restrictions on @old_bs.
2319 * Otherwise, bdrv_check_perm() on @old_bs would re-initiate
2320 * updating the permissions of @new_bs, and thus not purely loosen
2321 * restrictions.
2322 */
2323 if (new_bs) {
2324 bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm);
2325 bdrv_set_perm(new_bs, perm, shared_perm);
2326 }
2327
2328 if (old_bs) {
2329 /* Update permissions for old node. This is guaranteed to succeed
2330 * because we're just taking a parent away, so we're loosening
2331 * restrictions. */
2332 bool tighten_restrictions;
2333 int ret;
2334
2335 bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm);
2336 ret = bdrv_check_perm(old_bs, NULL, perm, shared_perm, NULL,
2337 &tighten_restrictions, NULL);
2338 assert(tighten_restrictions == false);
2339 if (ret < 0) {
2340 /* We only tried to loosen restrictions, so errors are not fatal */
2341 bdrv_abort_perm_update(old_bs);
2342 } else {
2343 bdrv_set_perm(old_bs, perm, shared_perm);
2344 }
2345
2346 /* When the parent requiring a non-default AioContext is removed, the
2347 * node moves back to the main AioContext */
2348 bdrv_try_set_aio_context(old_bs, qemu_get_aio_context(), NULL);
2349 }
2350}
2351
2352/*
2353 * This function steals the reference to child_bs from the caller.
2354 * That reference is later dropped by bdrv_root_unref_child().
2355 *
2356 * On failure NULL is returned, errp is set and the reference to
2357 * child_bs is also dropped.
2358 *
2359 * The caller must hold the AioContext lock @child_bs, but not that of @ctx
2360 * (unless @child_bs is already in @ctx).
2361 */
2362BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
2363 const char *child_name,
2364 const BdrvChildRole *child_role,
2365 AioContext *ctx,
2366 uint64_t perm, uint64_t shared_perm,
2367 void *opaque, Error **errp)
2368{
2369 BdrvChild *child;
2370 Error *local_err = NULL;
2371 int ret;
2372
2373 ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, NULL,
2374 errp);
2375 if (ret < 0) {
2376 bdrv_abort_perm_update(child_bs);
2377 bdrv_unref(child_bs);
2378 return NULL;
2379 }
2380
2381 child = g_new(BdrvChild, 1);
2382 *child = (BdrvChild) {
2383 .bs = NULL,
2384 .name = g_strdup(child_name),
2385 .role = child_role,
2386 .perm = perm,
2387 .shared_perm = shared_perm,
2388 .opaque = opaque,
2389 };
2390
2391 /* If the AioContexts don't match, first try to move the subtree of
2392 * child_bs into the AioContext of the new parent. If this doesn't work,
2393 * try moving the parent into the AioContext of child_bs instead. */
2394 if (bdrv_get_aio_context(child_bs) != ctx) {
2395 ret = bdrv_try_set_aio_context(child_bs, ctx, &local_err);
2396 if (ret < 0 && child_role->can_set_aio_ctx) {
2397 GSList *ignore = g_slist_prepend(NULL, child);;
2398 ctx = bdrv_get_aio_context(child_bs);
2399 if (child_role->can_set_aio_ctx(child, ctx, &ignore, NULL)) {
2400 error_free(local_err);
2401 ret = 0;
2402 g_slist_free(ignore);
2403 ignore = g_slist_prepend(NULL, child);;
2404 child_role->set_aio_ctx(child, ctx, &ignore);
2405 }
2406 g_slist_free(ignore);
2407 }
2408 if (ret < 0) {
2409 error_propagate(errp, local_err);
2410 g_free(child);
2411 bdrv_abort_perm_update(child_bs);
2412 return NULL;
2413 }
2414 }
2415
2416 /* This performs the matching bdrv_set_perm() for the above check. */
2417 bdrv_replace_child(child, child_bs);
2418
2419 return child;
2420}
2421
2422/*
2423 * This function transfers the reference to child_bs from the caller
2424 * to parent_bs. That reference is later dropped by parent_bs on
2425 * bdrv_close() or if someone calls bdrv_unref_child().
2426 *
2427 * On failure NULL is returned, errp is set and the reference to
2428 * child_bs is also dropped.
2429 *
2430 * If @parent_bs and @child_bs are in different AioContexts, the caller must
2431 * hold the AioContext lock for @child_bs, but not for @parent_bs.
2432 */
2433BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
2434 BlockDriverState *child_bs,
2435 const char *child_name,
2436 const BdrvChildRole *child_role,
2437 Error **errp)
2438{
2439 BdrvChild *child;
2440 uint64_t perm, shared_perm;
2441
2442 bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm);
2443
2444 assert(parent_bs->drv);
2445 bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL,
2446 perm, shared_perm, &perm, &shared_perm);
2447
2448 child = bdrv_root_attach_child(child_bs, child_name, child_role,
2449 bdrv_get_aio_context(parent_bs),
2450 perm, shared_perm, parent_bs, errp);
2451 if (child == NULL) {
2452 return NULL;
2453 }
2454
2455 QLIST_INSERT_HEAD(&parent_bs->children, child, next);
2456 return child;
2457}
2458
2459static void bdrv_detach_child(BdrvChild *child)
2460{
2461 if (child->next.le_prev) {
2462 QLIST_REMOVE(child, next);
2463 child->next.le_prev = NULL;
2464 }
2465
2466 bdrv_replace_child(child, NULL);
2467
2468 g_free(child->name);
2469 g_free(child);
2470}
2471
2472void bdrv_root_unref_child(BdrvChild *child)
2473{
2474 BlockDriverState *child_bs;
2475
2476 child_bs = child->bs;
2477 bdrv_detach_child(child);
2478 bdrv_unref(child_bs);
2479}
2480
2481/**
2482 * Clear all inherits_from pointers from children and grandchildren of
2483 * @root that point to @root, where necessary.
2484 */
2485static void bdrv_unset_inherits_from(BlockDriverState *root, BdrvChild *child)
2486{
2487 BdrvChild *c;
2488
2489 if (child->bs->inherits_from == root) {
2490 /*
2491 * Remove inherits_from only when the last reference between root and
2492 * child->bs goes away.
2493 */
2494 QLIST_FOREACH(c, &root->children, next) {
2495 if (c != child && c->bs == child->bs) {
2496 break;
2497 }
2498 }
2499 if (c == NULL) {
2500 child->bs->inherits_from = NULL;
2501 }
2502 }
2503
2504 QLIST_FOREACH(c, &child->bs->children, next) {
2505 bdrv_unset_inherits_from(root, c);
2506 }
2507}
2508
2509void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child)
2510{
2511 if (child == NULL) {
2512 return;
2513 }
2514
2515 bdrv_unset_inherits_from(parent, child);
2516 bdrv_root_unref_child(child);
2517}
2518
2519
2520static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load)
2521{
2522 BdrvChild *c;
2523 QLIST_FOREACH(c, &bs->parents, next_parent) {
2524 if (c->role->change_media) {
2525 c->role->change_media(c, load);
2526 }
2527 }
2528}
2529
2530/* Return true if you can reach parent going through child->inherits_from
2531 * recursively. If parent or child are NULL, return false */
2532static bool bdrv_inherits_from_recursive(BlockDriverState *child,
2533 BlockDriverState *parent)
2534{
2535 while (child && child != parent) {
2536 child = child->inherits_from;
2537 }
2538
2539 return child != NULL;
2540}
2541
2542/*
2543 * Sets the backing file link of a BDS. A new reference is created; callers
2544 * which don't need their own reference any more must call bdrv_unref().
2545 */
2546void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
2547 Error **errp)
2548{
2549 bool update_inherits_from = bdrv_chain_contains(bs, backing_hd) &&
2550 bdrv_inherits_from_recursive(backing_hd, bs);
2551
2552 if (bdrv_is_backing_chain_frozen(bs, backing_bs(bs), errp)) {
2553 return;
2554 }
2555
2556 if (backing_hd) {
2557 bdrv_ref(backing_hd);
2558 }
2559
2560 if (bs->backing) {
2561 bdrv_unref_child(bs, bs->backing);
2562 }
2563
2564 if (!backing_hd) {
2565 bs->backing = NULL;
2566 goto out;
2567 }
2568
2569 bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing,
2570 errp);
2571 /* If backing_hd was already part of bs's backing chain, and
2572 * inherits_from pointed recursively to bs then let's update it to
2573 * point directly to bs (else it will become NULL). */
2574 if (bs->backing && update_inherits_from) {
2575 backing_hd->inherits_from = bs;
2576 }
2577
2578out:
2579 bdrv_refresh_limits(bs, NULL);
2580}
2581
2582/*
2583 * Opens the backing file for a BlockDriverState if not yet open
2584 *
2585 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
2586 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2587 * itself, all options starting with "${bdref_key}." are considered part of the
2588 * BlockdevRef.
2589 *
2590 * TODO Can this be unified with bdrv_open_image()?
2591 */
2592int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
2593 const char *bdref_key, Error **errp)
2594{
2595 char *backing_filename = NULL;
2596 char *bdref_key_dot;
2597 const char *reference = NULL;
2598 int ret = 0;
2599 bool implicit_backing = false;
2600 BlockDriverState *backing_hd;
2601 QDict *options;
2602 QDict *tmp_parent_options = NULL;
2603 Error *local_err = NULL;
2604
2605 if (bs->backing != NULL) {
2606 goto free_exit;
2607 }
2608
2609 /* NULL means an empty set of options */
2610 if (parent_options == NULL) {
2611 tmp_parent_options = qdict_new();
2612 parent_options = tmp_parent_options;
2613 }
2614
2615 bs->open_flags &= ~BDRV_O_NO_BACKING;
2616
2617 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
2618 qdict_extract_subqdict(parent_options, &options, bdref_key_dot);
2619 g_free(bdref_key_dot);
2620
2621 /*
2622 * Caution: while qdict_get_try_str() is fine, getting non-string
2623 * types would require more care. When @parent_options come from
2624 * -blockdev or blockdev_add, its members are typed according to
2625 * the QAPI schema, but when they come from -drive, they're all
2626 * QString.
2627 */
2628 reference = qdict_get_try_str(parent_options, bdref_key);
2629 if (reference || qdict_haskey(options, "file.filename")) {
2630 /* keep backing_filename NULL */
2631 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
2632 qobject_unref(options);
2633 goto free_exit;
2634 } else {
2635 if (qdict_size(options) == 0) {
2636 /* If the user specifies options that do not modify the
2637 * backing file's behavior, we might still consider it the
2638 * implicit backing file. But it's easier this way, and
2639 * just specifying some of the backing BDS's options is
2640 * only possible with -drive anyway (otherwise the QAPI
2641 * schema forces the user to specify everything). */
2642 implicit_backing = !strcmp(bs->auto_backing_file, bs->backing_file);
2643 }
2644
2645 backing_filename = bdrv_get_full_backing_filename(bs, &local_err);
2646 if (local_err) {
2647 ret = -EINVAL;
2648 error_propagate(errp, local_err);
2649 qobject_unref(options);
2650 goto free_exit;
2651 }
2652 }
2653
2654 if (!bs->drv || !bs->drv->supports_backing) {
2655 ret = -EINVAL;
2656 error_setg(errp, "Driver doesn't support backing files");
2657 qobject_unref(options);
2658 goto free_exit;
2659 }
2660
2661 if (!reference &&
2662 bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) {
2663 qdict_put_str(options, "driver", bs->backing_format);
2664 }
2665
2666 backing_hd = bdrv_open_inherit(backing_filename, reference, options, 0, bs,
2667 &child_backing, errp);
2668 if (!backing_hd) {
2669 bs->open_flags |= BDRV_O_NO_BACKING;
2670 error_prepend(errp, "Could not open backing file: ");
2671 ret = -EINVAL;
2672 goto free_exit;
2673 }
2674
2675 if (implicit_backing) {
2676 bdrv_refresh_filename(backing_hd);
2677 pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file),
2678 backing_hd->filename);
2679 }
2680
2681 /* Hook up the backing file link; drop our reference, bs owns the
2682 * backing_hd reference now */
2683 bdrv_set_backing_hd(bs, backing_hd, &local_err);
2684 bdrv_unref(backing_hd);
2685 if (local_err) {
2686 error_propagate(errp, local_err);
2687 ret = -EINVAL;
2688 goto free_exit;
2689 }
2690
2691 qdict_del(parent_options, bdref_key);
2692
2693free_exit:
2694 g_free(backing_filename);
2695 qobject_unref(tmp_parent_options);
2696 return ret;
2697}
2698
2699static BlockDriverState *
2700bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
2701 BlockDriverState *parent, const BdrvChildRole *child_role,
2702 bool allow_none, Error **errp)
2703{
2704 BlockDriverState *bs = NULL;
2705 QDict *image_options;
2706 char *bdref_key_dot;
2707 const char *reference;
2708
2709 assert(child_role != NULL);
2710
2711 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
2712 qdict_extract_subqdict(options, &image_options, bdref_key_dot);
2713 g_free(bdref_key_dot);
2714
2715 /*
2716 * Caution: while qdict_get_try_str() is fine, getting non-string
2717 * types would require more care. When @options come from
2718 * -blockdev or blockdev_add, its members are typed according to
2719 * the QAPI schema, but when they come from -drive, they're all
2720 * QString.
2721 */
2722 reference = qdict_get_try_str(options, bdref_key);
2723 if (!filename && !reference && !qdict_size(image_options)) {
2724 if (!allow_none) {
2725 error_setg(errp, "A block device must be specified for \"%s\"",
2726 bdref_key);
2727 }
2728 qobject_unref(image_options);
2729 goto done;
2730 }
2731
2732 bs = bdrv_open_inherit(filename, reference, image_options, 0,
2733 parent, child_role, errp);
2734 if (!bs) {
2735 goto done;
2736 }
2737
2738done:
2739 qdict_del(options, bdref_key);
2740 return bs;
2741}
2742
2743/*
2744 * Opens a disk image whose options are given as BlockdevRef in another block
2745 * device's options.
2746 *
2747 * If allow_none is true, no image will be opened if filename is false and no
2748 * BlockdevRef is given. NULL will be returned, but errp remains unset.
2749 *
2750 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
2751 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2752 * itself, all options starting with "${bdref_key}." are considered part of the
2753 * BlockdevRef.
2754 *
2755 * The BlockdevRef will be removed from the options QDict.
2756 */
2757BdrvChild *bdrv_open_child(const char *filename,
2758 QDict *options, const char *bdref_key,
2759 BlockDriverState *parent,
2760 const BdrvChildRole *child_role,
2761 bool allow_none, Error **errp)
2762{
2763 BlockDriverState *bs;
2764
2765 bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_role,
2766 allow_none, errp);
2767 if (bs == NULL) {
2768 return NULL;
2769 }
2770
2771 return bdrv_attach_child(parent, bs, bdref_key, child_role, errp);
2772}
2773
2774/* TODO Future callers may need to specify parent/child_role in order for
2775 * option inheritance to work. Existing callers use it for the root node. */
2776BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp)
2777{
2778 BlockDriverState *bs = NULL;
2779 Error *local_err = NULL;
2780 QObject *obj = NULL;
2781 QDict *qdict = NULL;
2782 const char *reference = NULL;
2783 Visitor *v = NULL;
2784
2785 if (ref->type == QTYPE_QSTRING) {
2786 reference = ref->u.reference;
2787 } else {
2788 BlockdevOptions *options = &ref->u.definition;
2789 assert(ref->type == QTYPE_QDICT);
2790
2791 v = qobject_output_visitor_new(&obj);
2792 visit_type_BlockdevOptions(v, NULL, &options, &local_err);
2793 if (local_err) {
2794 error_propagate(errp, local_err);
2795 goto fail;
2796 }
2797 visit_complete(v, &obj);
2798
2799 qdict = qobject_to(QDict, obj);
2800 qdict_flatten(qdict);
2801
2802 /* bdrv_open_inherit() defaults to the values in bdrv_flags (for
2803 * compatibility with other callers) rather than what we want as the
2804 * real defaults. Apply the defaults here instead. */
2805 qdict_set_default_str(qdict, BDRV_OPT_CACHE_DIRECT, "off");
2806 qdict_set_default_str(qdict, BDRV_OPT_CACHE_NO_FLUSH, "off");
2807 qdict_set_default_str(qdict, BDRV_OPT_READ_ONLY, "off");
2808 qdict_set_default_str(qdict, BDRV_OPT_AUTO_READ_ONLY, "off");
2809
2810 }
2811
2812 bs = bdrv_open_inherit(NULL, reference, qdict, 0, NULL, NULL, errp);
2813 obj = NULL;
2814
2815fail:
2816 qobject_unref(obj);
2817 visit_free(v);
2818 return bs;
2819}
2820
2821static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
2822 int flags,
2823 QDict *snapshot_options,
2824 Error **errp)
2825{
2826 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
2827 char *tmp_filename = g_malloc0(PATH_MAX + 1);
2828 int64_t total_size;
2829 QemuOpts *opts = NULL;
2830 BlockDriverState *bs_snapshot = NULL;
2831 Error *local_err = NULL;
2832 int ret;
2833
2834 /* if snapshot, we create a temporary backing file and open it
2835 instead of opening 'filename' directly */
2836
2837 /* Get the required size from the image */
2838 total_size = bdrv_getlength(bs);
2839 if (total_size < 0) {
2840 error_setg_errno(errp, -total_size, "Could not get image size");
2841 goto out;
2842 }
2843
2844 /* Create the temporary image */
2845 ret = get_tmp_filename(tmp_filename, PATH_MAX + 1);
2846 if (ret < 0) {
2847 error_setg_errno(errp, -ret, "Could not get temporary filename");
2848 goto out;
2849 }
2850
2851 opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0,
2852 &error_abort);
2853 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort);
2854 ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp);
2855 qemu_opts_del(opts);
2856 if (ret < 0) {
2857 error_prepend(errp, "Could not create temporary overlay '%s': ",
2858 tmp_filename);
2859 goto out;
2860 }
2861
2862 /* Prepare options QDict for the temporary file */
2863 qdict_put_str(snapshot_options, "file.driver", "file");
2864 qdict_put_str(snapshot_options, "file.filename", tmp_filename);
2865 qdict_put_str(snapshot_options, "driver", "qcow2");
2866
2867 bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp);
2868 snapshot_options = NULL;
2869 if (!bs_snapshot) {
2870 goto out;
2871 }
2872
2873 /* bdrv_append() consumes a strong reference to bs_snapshot
2874 * (i.e. it will call bdrv_unref() on it) even on error, so in
2875 * order to be able to return one, we have to increase
2876 * bs_snapshot's refcount here */
2877 bdrv_ref(bs_snapshot);
2878 bdrv_append(bs_snapshot, bs, &local_err);
2879 if (local_err) {
2880 error_propagate(errp, local_err);
2881 bs_snapshot = NULL;
2882 goto out;
2883 }
2884
2885out:
2886 qobject_unref(snapshot_options);
2887 g_free(tmp_filename);
2888 return bs_snapshot;
2889}
2890
2891/*
2892 * Opens a disk image (raw, qcow2, vmdk, ...)
2893 *
2894 * options is a QDict of options to pass to the block drivers, or NULL for an
2895 * empty set of options. The reference to the QDict belongs to the block layer
2896 * after the call (even on failure), so if the caller intends to reuse the
2897 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
2898 *
2899 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
2900 * If it is not NULL, the referenced BDS will be reused.
2901 *
2902 * The reference parameter may be used to specify an existing block device which
2903 * should be opened. If specified, neither options nor a filename may be given,
2904 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
2905 */
2906static BlockDriverState *bdrv_open_inherit(const char *filename,
2907 const char *reference,
2908 QDict *options, int flags,
2909 BlockDriverState *parent,
2910 const BdrvChildRole *child_role,
2911 Error **errp)
2912{
2913 int ret;
2914 BlockBackend *file = NULL;
2915 BlockDriverState *bs;
2916 BlockDriver *drv = NULL;
2917 BdrvChild *child;
2918 const char *drvname;
2919 const char *backing;
2920 Error *local_err = NULL;
2921 QDict *snapshot_options = NULL;
2922 int snapshot_flags = 0;
2923
2924 assert(!child_role || !flags);
2925 assert(!child_role == !parent);
2926
2927 if (reference) {
2928 bool options_non_empty = options ? qdict_size(options) : false;
2929 qobject_unref(options);
2930
2931 if (filename || options_non_empty) {
2932 error_setg(errp, "Cannot reference an existing block device with "
2933 "additional options or a new filename");
2934 return NULL;
2935 }
2936
2937 bs = bdrv_lookup_bs(reference, reference, errp);
2938 if (!bs) {
2939 return NULL;
2940 }
2941
2942 bdrv_ref(bs);
2943 return bs;
2944 }
2945
2946 bs = bdrv_new();
2947
2948 /* NULL means an empty set of options */
2949 if (options == NULL) {
2950 options = qdict_new();
2951 }
2952
2953 /* json: syntax counts as explicit options, as if in the QDict */
2954 parse_json_protocol(options, &filename, &local_err);
2955 if (local_err) {
2956 goto fail;
2957 }
2958
2959 bs->explicit_options = qdict_clone_shallow(options);
2960
2961 if (child_role) {
2962 bs->inherits_from = parent;
2963 child_role->inherit_options(&flags, options,
2964 parent->open_flags, parent->options);
2965 }
2966
2967 ret = bdrv_fill_options(&options, filename, &flags, &local_err);
2968 if (local_err) {
2969 goto fail;
2970 }
2971
2972 /*
2973 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
2974 * Caution: getting a boolean member of @options requires care.
2975 * When @options come from -blockdev or blockdev_add, members are
2976 * typed according to the QAPI schema, but when they come from
2977 * -drive, they're all QString.
2978 */
2979 if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") &&
2980 !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) {
2981 flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR);
2982 } else {
2983 flags &= ~BDRV_O_RDWR;
2984 }
2985
2986 if (flags & BDRV_O_SNAPSHOT) {
2987 snapshot_options = qdict_new();
2988 bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options,
2989 flags, options);
2990 /* Let bdrv_backing_options() override "read-only" */
2991 qdict_del(options, BDRV_OPT_READ_ONLY);
2992 bdrv_backing_options(&flags, options, flags, options);
2993 }
2994
2995 bs->open_flags = flags;
2996 bs->options = options;
2997 options = qdict_clone_shallow(options);
2998
2999 /* Find the right image format driver */
3000 /* See cautionary note on accessing @options above */
3001 drvname = qdict_get_try_str(options, "driver");
3002 if (drvname) {
3003 drv = bdrv_find_format(drvname);
3004 if (!drv) {
3005 error_setg(errp, "Unknown driver: '%s'", drvname);
3006 goto fail;
3007 }
3008 }
3009
3010 assert(drvname || !(flags & BDRV_O_PROTOCOL));
3011
3012 /* See cautionary note on accessing @options above */
3013 backing = qdict_get_try_str(options, "backing");
3014 if (qobject_to(QNull, qdict_get(options, "backing")) != NULL ||
3015 (backing && *backing == '\0'))
3016 {
3017 if (backing) {
3018 warn_report("Use of \"backing\": \"\" is deprecated; "
3019 "use \"backing\": null instead");
3020 }
3021 flags |= BDRV_O_NO_BACKING;
3022 qdict_del(options, "backing");
3023 }
3024
3025 /* Open image file without format layer. This BlockBackend is only used for
3026 * probing, the block drivers will do their own bdrv_open_child() for the
3027 * same BDS, which is why we put the node name back into options. */
3028 if ((flags & BDRV_O_PROTOCOL) == 0) {
3029 BlockDriverState *file_bs;
3030
3031 file_bs = bdrv_open_child_bs(filename, options, "file", bs,
3032 &child_file, true, &local_err);
3033 if (local_err) {
3034 goto fail;
3035 }
3036 if (file_bs != NULL) {
3037 /* Not requesting BLK_PERM_CONSISTENT_READ because we're only
3038 * looking at the header to guess the image format. This works even
3039 * in cases where a guest would not see a consistent state. */
3040 file = blk_new(bdrv_get_aio_context(file_bs), 0, BLK_PERM_ALL);
3041 blk_insert_bs(file, file_bs, &local_err);
3042 bdrv_unref(file_bs);
3043 if (local_err) {
3044 goto fail;
3045 }
3046
3047 qdict_put_str(options, "file", bdrv_get_node_name(file_bs));
3048 }
3049 }
3050
3051 /* Image format probing */
3052 bs->probed = !drv;
3053 if (!drv && file) {
3054 ret = find_image_format(file, filename, &drv, &local_err);
3055 if (ret < 0) {
3056 goto fail;
3057 }
3058 /*
3059 * This option update would logically belong in bdrv_fill_options(),
3060 * but we first need to open bs->file for the probing to work, while
3061 * opening bs->file already requires the (mostly) final set of options
3062 * so that cache mode etc. can be inherited.
3063 *
3064 * Adding the driver later is somewhat ugly, but it's not an option
3065 * that would ever be inherited, so it's correct. We just need to make
3066 * sure to update both bs->options (which has the full effective
3067 * options for bs) and options (which has file.* already removed).
3068 */
3069 qdict_put_str(bs->options, "driver", drv->format_name);
3070 qdict_put_str(options, "driver", drv->format_name);
3071 } else if (!drv) {
3072 error_setg(errp, "Must specify either driver or file");
3073 goto fail;
3074 }
3075
3076 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
3077 assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open);
3078 /* file must be NULL if a protocol BDS is about to be created
3079 * (the inverse results in an error message from bdrv_open_common()) */
3080 assert(!(flags & BDRV_O_PROTOCOL) || !file);
3081
3082 /* Open the image */
3083 ret = bdrv_open_common(bs, file, options, &local_err);
3084 if (ret < 0) {
3085 goto fail;
3086 }
3087
3088 if (file) {
3089 blk_unref(file);
3090 file = NULL;
3091 }
3092
3093 /* If there is a backing file, use it */
3094 if ((flags & BDRV_O_NO_BACKING) == 0) {
3095 ret = bdrv_open_backing_file(bs, options, "backing", &local_err);
3096 if (ret < 0) {
3097 goto close_and_fail;
3098 }
3099 }
3100
3101 /* Remove all children options and references
3102 * from bs->options and bs->explicit_options */
3103 QLIST_FOREACH(child, &bs->children, next) {
3104 char *child_key_dot;
3105 child_key_dot = g_strdup_printf("%s.", child->name);
3106 qdict_extract_subqdict(bs->explicit_options, NULL, child_key_dot);
3107 qdict_extract_subqdict(bs->options, NULL, child_key_dot);
3108 qdict_del(bs->explicit_options, child->name);
3109 qdict_del(bs->options, child->name);
3110 g_free(child_key_dot);
3111 }
3112
3113 /* Check if any unknown options were used */
3114 if (qdict_size(options) != 0) {
3115 const QDictEntry *entry = qdict_first(options);
3116 if (flags & BDRV_O_PROTOCOL) {
3117 error_setg(errp, "Block protocol '%s' doesn't support the option "
3118 "'%s'", drv->format_name, entry->key);
3119 } else {
3120 error_setg(errp,
3121 "Block format '%s' does not support the option '%s'",
3122 drv->format_name, entry->key);
3123 }
3124
3125 goto close_and_fail;
3126 }
3127
3128 bdrv_parent_cb_change_media(bs, true);
3129
3130 qobject_unref(options);
3131 options = NULL;
3132
3133 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
3134 * temporary snapshot afterwards. */
3135 if (snapshot_flags) {
3136 BlockDriverState *snapshot_bs;
3137 snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags,
3138 snapshot_options, &local_err);
3139 snapshot_options = NULL;
3140 if (local_err) {
3141 goto close_and_fail;
3142 }
3143 /* We are not going to return bs but the overlay on top of it
3144 * (snapshot_bs); thus, we have to drop the strong reference to bs
3145 * (which we obtained by calling bdrv_new()). bs will not be deleted,
3146 * though, because the overlay still has a reference to it. */
3147 bdrv_unref(bs);
3148 bs = snapshot_bs;
3149 }
3150
3151 return bs;
3152
3153fail:
3154 blk_unref(file);
3155 qobject_unref(snapshot_options);
3156 qobject_unref(bs->explicit_options);
3157 qobject_unref(bs->options);
3158 qobject_unref(options);
3159 bs->options = NULL;
3160 bs->explicit_options = NULL;
3161 bdrv_unref(bs);
3162 error_propagate(errp, local_err);
3163 return NULL;
3164
3165close_and_fail:
3166 bdrv_unref(bs);
3167 qobject_unref(snapshot_options);
3168 qobject_unref(options);
3169 error_propagate(errp, local_err);
3170 return NULL;
3171}
3172
3173BlockDriverState *bdrv_open(const char *filename, const char *reference,
3174 QDict *options, int flags, Error **errp)
3175{
3176 return bdrv_open_inherit(filename, reference, options, flags, NULL,
3177 NULL, errp);
3178}
3179
3180/* Return true if the NULL-terminated @list contains @str */
3181static bool is_str_in_list(const char *str, const char *const *list)
3182{
3183 if (str && list) {
3184 int i;
3185 for (i = 0; list[i] != NULL; i++) {
3186 if (!strcmp(str, list[i])) {
3187 return true;
3188 }
3189 }
3190 }
3191 return false;
3192}
3193
3194/*
3195 * Check that every option set in @bs->options is also set in
3196 * @new_opts.
3197 *
3198 * Options listed in the common_options list and in
3199 * @bs->drv->mutable_opts are skipped.
3200 *
3201 * Return 0 on success, otherwise return -EINVAL and set @errp.
3202 */
3203static int bdrv_reset_options_allowed(BlockDriverState *bs,
3204 const QDict *new_opts, Error **errp)
3205{
3206 const QDictEntry *e;
3207 /* These options are common to all block drivers and are handled
3208 * in bdrv_reopen_prepare() so they can be left out of @new_opts */
3209 const char *const common_options[] = {
3210 "node-name", "discard", "cache.direct", "cache.no-flush",
3211 "read-only", "auto-read-only", "detect-zeroes", NULL
3212 };
3213
3214 for (e = qdict_first(bs->options); e; e = qdict_next(bs->options, e)) {
3215 if (!qdict_haskey(new_opts, e->key) &&
3216 !is_str_in_list(e->key, common_options) &&
3217 !is_str_in_list(e->key, bs->drv->mutable_opts)) {
3218 error_setg(errp, "Option '%s' cannot be reset "
3219 "to its default value", e->key);
3220 return -EINVAL;
3221 }
3222 }
3223
3224 return 0;
3225}
3226
3227/*
3228 * Returns true if @child can be reached recursively from @bs
3229 */
3230static bool bdrv_recurse_has_child(BlockDriverState *bs,
3231 BlockDriverState *child)
3232{
3233 BdrvChild *c;
3234
3235 if (bs == child) {
3236 return true;
3237 }
3238
3239 QLIST_FOREACH(c, &bs->children, next) {
3240 if (bdrv_recurse_has_child(c->bs, child)) {
3241 return true;
3242 }
3243 }
3244
3245 return false;
3246}
3247
3248/*
3249 * Adds a BlockDriverState to a simple queue for an atomic, transactional
3250 * reopen of multiple devices.
3251 *
3252 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT
3253 * already performed, or alternatively may be NULL a new BlockReopenQueue will
3254 * be created and initialized. This newly created BlockReopenQueue should be
3255 * passed back in for subsequent calls that are intended to be of the same
3256 * atomic 'set'.
3257 *
3258 * bs is the BlockDriverState to add to the reopen queue.
3259 *
3260 * options contains the changed options for the associated bs
3261 * (the BlockReopenQueue takes ownership)
3262 *
3263 * flags contains the open flags for the associated bs
3264 *
3265 * returns a pointer to bs_queue, which is either the newly allocated
3266 * bs_queue, or the existing bs_queue being used.
3267 *
3268 * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple().
3269 */
3270static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
3271 BlockDriverState *bs,
3272 QDict *options,
3273 const BdrvChildRole *role,
3274 QDict *parent_options,
3275 int parent_flags,
3276 bool keep_old_opts)
3277{
3278 assert(bs != NULL);
3279
3280 BlockReopenQueueEntry *bs_entry;
3281 BdrvChild *child;
3282 QDict *old_options, *explicit_options, *options_copy;
3283 int flags;
3284 QemuOpts *opts;
3285
3286 /* Make sure that the caller remembered to use a drained section. This is
3287 * important to avoid graph changes between the recursive queuing here and
3288 * bdrv_reopen_multiple(). */
3289 assert(bs->quiesce_counter > 0);
3290
3291 if (bs_queue == NULL) {
3292 bs_queue = g_new0(BlockReopenQueue, 1);
3293 QSIMPLEQ_INIT(bs_queue);
3294 }
3295
3296 if (!options) {
3297 options = qdict_new();
3298 }
3299
3300 /* Check if this BlockDriverState is already in the queue */
3301 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
3302 if (bs == bs_entry->state.bs) {
3303 break;
3304 }
3305 }
3306
3307 /*
3308 * Precedence of options:
3309 * 1. Explicitly passed in options (highest)
3310 * 2. Retained from explicitly set options of bs
3311 * 3. Inherited from parent node
3312 * 4. Retained from effective options of bs
3313 */
3314
3315 /* Old explicitly set values (don't overwrite by inherited value) */
3316 if (bs_entry || keep_old_opts) {
3317 old_options = qdict_clone_shallow(bs_entry ?
3318 bs_entry->state.explicit_options :
3319 bs->explicit_options);
3320 bdrv_join_options(bs, options, old_options);
3321 qobject_unref(old_options);
3322 }
3323
3324 explicit_options = qdict_clone_shallow(options);
3325
3326 /* Inherit from parent node */
3327 if (parent_options) {
3328 flags = 0;
3329 role->inherit_options(&flags, options, parent_flags, parent_options);
3330 } else {
3331 flags = bdrv_get_flags(bs);
3332 }
3333
3334 if (keep_old_opts) {
3335 /* Old values are used for options that aren't set yet */
3336 old_options = qdict_clone_shallow(bs->options);
3337 bdrv_join_options(bs, options, old_options);
3338 qobject_unref(old_options);
3339 }
3340
3341 /* We have the final set of options so let's update the flags */
3342 options_copy = qdict_clone_shallow(options);
3343 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
3344 qemu_opts_absorb_qdict(opts, options_copy, NULL);
3345 update_flags_from_options(&flags, opts);
3346 qemu_opts_del(opts);
3347 qobject_unref(options_copy);
3348
3349 /* bdrv_open_inherit() sets and clears some additional flags internally */
3350 flags &= ~BDRV_O_PROTOCOL;
3351 if (flags & BDRV_O_RDWR) {
3352 flags |= BDRV_O_ALLOW_RDWR;
3353 }
3354
3355 if (!bs_entry) {
3356 bs_entry = g_new0(BlockReopenQueueEntry, 1);
3357 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry);
3358 } else {
3359 qobject_unref(bs_entry->state.options);
3360 qobject_unref(bs_entry->state.explicit_options);
3361 }
3362
3363 bs_entry->state.bs = bs;
3364 bs_entry->state.options = options;
3365 bs_entry->state.explicit_options = explicit_options;
3366 bs_entry->state.flags = flags;
3367
3368 /* This needs to be overwritten in bdrv_reopen_prepare() */
3369 bs_entry->state.perm = UINT64_MAX;
3370 bs_entry->state.shared_perm = 0;
3371
3372 /*
3373 * If keep_old_opts is false then it means that unspecified
3374 * options must be reset to their original value. We don't allow
3375 * resetting 'backing' but we need to know if the option is
3376 * missing in order to decide if we have to return an error.
3377 */
3378 if (!keep_old_opts) {
3379 bs_entry->state.backing_missing =
3380 !qdict_haskey(options, "backing") &&
3381 !qdict_haskey(options, "backing.driver");
3382 }
3383
3384 QLIST_FOREACH(child, &bs->children, next) {
3385 QDict *new_child_options = NULL;
3386 bool child_keep_old = keep_old_opts;
3387
3388 /* reopen can only change the options of block devices that were
3389 * implicitly created and inherited options. For other (referenced)
3390 * block devices, a syntax like "backing.foo" results in an error. */
3391 if (child->bs->inherits_from != bs) {
3392 continue;
3393 }
3394
3395 /* Check if the options contain a child reference */
3396 if (qdict_haskey(options, child->name)) {
3397 const char *childref = qdict_get_try_str(options, child->name);
3398 /*
3399 * The current child must not be reopened if the child
3400 * reference is null or points to a different node.
3401 */
3402 if (g_strcmp0(childref, child->bs->node_name)) {
3403 continue;
3404 }
3405 /*
3406 * If the child reference points to the current child then
3407 * reopen it with its existing set of options (note that
3408 * it can still inherit new options from the parent).
3409 */
3410 child_keep_old = true;
3411 } else {
3412 /* Extract child options ("child-name.*") */
3413 char *child_key_dot = g_strdup_printf("%s.", child->name);
3414 qdict_extract_subqdict(explicit_options, NULL, child_key_dot);
3415 qdict_extract_subqdict(options, &new_child_options, child_key_dot);
3416 g_free(child_key_dot);
3417 }
3418
3419 bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options,
3420 child->role, options, flags, child_keep_old);
3421 }
3422
3423 return bs_queue;
3424}
3425
3426BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
3427 BlockDriverState *bs,
3428 QDict *options, bool keep_old_opts)
3429{
3430 return bdrv_reopen_queue_child(bs_queue, bs, options, NULL, NULL, 0,
3431 keep_old_opts);
3432}
3433
3434/*
3435 * Reopen multiple BlockDriverStates atomically & transactionally.
3436 *
3437 * The queue passed in (bs_queue) must have been built up previous
3438 * via bdrv_reopen_queue().
3439 *
3440 * Reopens all BDS specified in the queue, with the appropriate
3441 * flags. All devices are prepared for reopen, and failure of any
3442 * device will cause all device changes to be abandoned, and intermediate
3443 * data cleaned up.
3444 *
3445 * If all devices prepare successfully, then the changes are committed
3446 * to all devices.
3447 *
3448 * All affected nodes must be drained between bdrv_reopen_queue() and
3449 * bdrv_reopen_multiple().
3450 */
3451int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
3452{
3453 int ret = -1;
3454 BlockReopenQueueEntry *bs_entry, *next;
3455
3456 assert(bs_queue != NULL);
3457
3458 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
3459 assert(bs_entry->state.bs->quiesce_counter > 0);
3460 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, errp)) {
3461 goto cleanup;
3462 }
3463 bs_entry->prepared = true;
3464 }
3465
3466 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
3467 BDRVReopenState *state = &bs_entry->state;
3468 ret = bdrv_check_perm(state->bs, bs_queue, state->perm,
3469 state->shared_perm, NULL, NULL, errp);
3470 if (ret < 0) {
3471 goto cleanup_perm;
3472 }
3473 /* Check if new_backing_bs would accept the new permissions */
3474 if (state->replace_backing_bs && state->new_backing_bs) {
3475 uint64_t nperm, nshared;
3476 bdrv_child_perm(state->bs, state->new_backing_bs,
3477 NULL, &child_backing, bs_queue,
3478 state->perm, state->shared_perm,
3479 &nperm, &nshared);
3480 ret = bdrv_check_update_perm(state->new_backing_bs, NULL,
3481 nperm, nshared, NULL, NULL, errp);
3482 if (ret < 0) {
3483 goto cleanup_perm;
3484 }
3485 }
3486 bs_entry->perms_checked = true;
3487 }
3488
3489 /* If we reach this point, we have success and just need to apply the
3490 * changes
3491 */
3492 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
3493 bdrv_reopen_commit(&bs_entry->state);
3494 }
3495
3496 ret = 0;
3497cleanup_perm:
3498 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
3499 BDRVReopenState *state = &bs_entry->state;
3500
3501 if (!bs_entry->perms_checked) {
3502 continue;
3503 }
3504
3505 if (ret == 0) {
3506 bdrv_set_perm(state->bs, state->perm, state->shared_perm);
3507 } else {
3508 bdrv_abort_perm_update(state->bs);
3509 if (state->replace_backing_bs && state->new_backing_bs) {
3510 bdrv_abort_perm_update(state->new_backing_bs);
3511 }
3512 }
3513 }
3514cleanup:
3515 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
3516 if (ret) {
3517 if (bs_entry->prepared) {
3518 bdrv_reopen_abort(&bs_entry->state);
3519 }
3520 qobject_unref(bs_entry->state.explicit_options);
3521 qobject_unref(bs_entry->state.options);
3522 }
3523 if (bs_entry->state.new_backing_bs) {
3524 bdrv_unref(bs_entry->state.new_backing_bs);
3525 }
3526 g_free(bs_entry);
3527 }
3528 g_free(bs_queue);
3529
3530 return ret;
3531}
3532
3533int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
3534 Error **errp)
3535{
3536 int ret;
3537 BlockReopenQueue *queue;
3538 QDict *opts = qdict_new();
3539
3540 qdict_put_bool(opts, BDRV_OPT_READ_ONLY, read_only);
3541
3542 bdrv_subtree_drained_begin(bs);
3543 queue = bdrv_reopen_queue(NULL, bs, opts, true);
3544 ret = bdrv_reopen_multiple(queue, errp);
3545 bdrv_subtree_drained_end(bs);
3546
3547 return ret;
3548}
3549
3550static BlockReopenQueueEntry *find_parent_in_reopen_queue(BlockReopenQueue *q,
3551 BdrvChild *c)
3552{
3553 BlockReopenQueueEntry *entry;
3554
3555 QSIMPLEQ_FOREACH(entry, q, entry) {
3556 BlockDriverState *bs = entry->state.bs;
3557 BdrvChild *child;
3558
3559 QLIST_FOREACH(child, &bs->children, next) {
3560 if (child == c) {
3561 return entry;
3562 }
3563 }
3564 }
3565
3566 return NULL;
3567}
3568
3569static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs,
3570 uint64_t *perm, uint64_t *shared)
3571{
3572 BdrvChild *c;
3573 BlockReopenQueueEntry *parent;
3574 uint64_t cumulative_perms = 0;
3575 uint64_t cumulative_shared_perms = BLK_PERM_ALL;
3576
3577 QLIST_FOREACH(c, &bs->parents, next_parent) {
3578 parent = find_parent_in_reopen_queue(q, c);
3579 if (!parent) {
3580 cumulative_perms |= c->perm;
3581 cumulative_shared_perms &= c->shared_perm;
3582 } else {
3583 uint64_t nperm, nshared;
3584
3585 bdrv_child_perm(parent->state.bs, bs, c, c->role, q,
3586 parent->state.perm, parent->state.shared_perm,
3587 &nperm, &nshared);
3588
3589 cumulative_perms |= nperm;
3590 cumulative_shared_perms &= nshared;
3591 }
3592 }
3593 *perm = cumulative_perms;
3594 *shared = cumulative_shared_perms;
3595}
3596
3597/*
3598 * Take a BDRVReopenState and check if the value of 'backing' in the
3599 * reopen_state->options QDict is valid or not.
3600 *
3601 * If 'backing' is missing from the QDict then return 0.
3602 *
3603 * If 'backing' contains the node name of the backing file of
3604 * reopen_state->bs then return 0.
3605 *
3606 * If 'backing' contains a different node name (or is null) then check
3607 * whether the current backing file can be replaced with the new one.
3608 * If that's the case then reopen_state->replace_backing_bs is set to
3609 * true and reopen_state->new_backing_bs contains a pointer to the new
3610 * backing BlockDriverState (or NULL).
3611 *
3612 * Return 0 on success, otherwise return < 0 and set @errp.
3613 */
3614static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state,
3615 Error **errp)
3616{
3617 BlockDriverState *bs = reopen_state->bs;
3618 BlockDriverState *overlay_bs, *new_backing_bs;
3619 QObject *value;
3620 const char *str;
3621
3622 value = qdict_get(reopen_state->options, "backing");
3623 if (value == NULL) {
3624 return 0;
3625 }
3626
3627 switch (qobject_type(value)) {
3628 case QTYPE_QNULL:
3629 new_backing_bs = NULL;
3630 break;
3631 case QTYPE_QSTRING:
3632 str = qobject_get_try_str(value);
3633 new_backing_bs = bdrv_lookup_bs(NULL, str, errp);
3634 if (new_backing_bs == NULL) {
3635 return -EINVAL;
3636 } else if (bdrv_recurse_has_child(new_backing_bs, bs)) {
3637 error_setg(errp, "Making '%s' a backing file of '%s' "
3638 "would create a cycle", str, bs->node_name);
3639 return -EINVAL;
3640 }
3641 break;
3642 default:
3643 /* 'backing' does not allow any other data type */
3644 g_assert_not_reached();
3645 }
3646
3647 /*
3648 * TODO: before removing the x- prefix from x-blockdev-reopen we
3649 * should move the new backing file into the right AioContext
3650 * instead of returning an error.
3651 */
3652 if (new_backing_bs) {
3653 if (bdrv_get_aio_context(new_backing_bs) != bdrv_get_aio_context(bs)) {
3654 error_setg(errp, "Cannot use a new backing file "
3655 "with a different AioContext");
3656 return -EINVAL;
3657 }
3658 }
3659
3660 /*
3661 * Find the "actual" backing file by skipping all links that point
3662 * to an implicit node, if any (e.g. a commit filter node).
3663 */
3664 overlay_bs = bs;
3665 while (backing_bs(overlay_bs) && backing_bs(overlay_bs)->implicit) {
3666 overlay_bs = backing_bs(overlay_bs);
3667 }
3668
3669 /* If we want to replace the backing file we need some extra checks */
3670 if (new_backing_bs != backing_bs(overlay_bs)) {
3671 /* Check for implicit nodes between bs and its backing file */
3672 if (bs != overlay_bs) {
3673 error_setg(errp, "Cannot change backing link if '%s' has "
3674 "an implicit backing file", bs->node_name);
3675 return -EPERM;
3676 }
3677 /* Check if the backing link that we want to replace is frozen */
3678 if (bdrv_is_backing_chain_frozen(overlay_bs, backing_bs(overlay_bs),
3679 errp)) {
3680 return -EPERM;
3681 }
3682 reopen_state->replace_backing_bs = true;
3683 if (new_backing_bs) {
3684 bdrv_ref(new_backing_bs);
3685 reopen_state->new_backing_bs = new_backing_bs;
3686 }
3687 }
3688
3689 return 0;
3690}
3691
3692/*
3693 * Prepares a BlockDriverState for reopen. All changes are staged in the
3694 * 'opaque' field of the BDRVReopenState, which is used and allocated by
3695 * the block driver layer .bdrv_reopen_prepare()
3696 *
3697 * bs is the BlockDriverState to reopen
3698 * flags are the new open flags
3699 * queue is the reopen queue
3700 *
3701 * Returns 0 on success, non-zero on error. On error errp will be set
3702 * as well.
3703 *
3704 * On failure, bdrv_reopen_abort() will be called to clean up any data.
3705 * It is the responsibility of the caller to then call the abort() or
3706 * commit() for any other BDS that have been left in a prepare() state
3707 *
3708 */
3709int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
3710 Error **errp)
3711{
3712 int ret = -1;
3713 int old_flags;
3714 Error *local_err = NULL;
3715 BlockDriver *drv;
3716 QemuOpts *opts;
3717 QDict *orig_reopen_opts;
3718 char *discard = NULL;
3719 bool read_only;
3720 bool drv_prepared = false;
3721
3722 assert(reopen_state != NULL);
3723 assert(reopen_state->bs->drv != NULL);
3724 drv = reopen_state->bs->drv;
3725
3726 /* This function and each driver's bdrv_reopen_prepare() remove
3727 * entries from reopen_state->options as they are processed, so
3728 * we need to make a copy of the original QDict. */
3729 orig_reopen_opts = qdict_clone_shallow(reopen_state->options);
3730
3731 /* Process generic block layer options */
3732 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
3733 qemu_opts_absorb_qdict(opts, reopen_state->options, &local_err);
3734 if (local_err) {
3735 error_propagate(errp, local_err);
3736 ret = -EINVAL;
3737 goto error;
3738 }
3739
3740 /* This was already called in bdrv_reopen_queue_child() so the flags
3741 * are up-to-date. This time we simply want to remove the options from
3742 * QemuOpts in order to indicate that they have been processed. */
3743 old_flags = reopen_state->flags;
3744 update_flags_from_options(&reopen_state->flags, opts);
3745 assert(old_flags == reopen_state->flags);
3746
3747 discard = qemu_opt_get_del(opts, BDRV_OPT_DISCARD);
3748 if (discard != NULL) {
3749 if (bdrv_parse_discard_flags(discard, &reopen_state->flags) != 0) {
3750 error_setg(errp, "Invalid discard option");
3751 ret = -EINVAL;
3752 goto error;
3753 }
3754 }
3755
3756 reopen_state->detect_zeroes =
3757 bdrv_parse_detect_zeroes(opts, reopen_state->flags, &local_err);
3758 if (local_err) {
3759 error_propagate(errp, local_err);
3760 ret = -EINVAL;
3761 goto error;
3762 }
3763
3764 /* All other options (including node-name and driver) must be unchanged.
3765 * Put them back into the QDict, so that they are checked at the end
3766 * of this function. */
3767 qemu_opts_to_qdict(opts, reopen_state->options);
3768
3769 /* If we are to stay read-only, do not allow permission change
3770 * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is
3771 * not set, or if the BDS still has copy_on_read enabled */
3772 read_only = !(reopen_state->flags & BDRV_O_RDWR);
3773 ret = bdrv_can_set_read_only(reopen_state->bs, read_only, true, &local_err);
3774 if (local_err) {
3775 error_propagate(errp, local_err);
3776 goto error;
3777 }
3778
3779 /* Calculate required permissions after reopening */
3780 bdrv_reopen_perm(queue, reopen_state->bs,
3781 &reopen_state->perm, &reopen_state->shared_perm);
3782
3783 ret = bdrv_flush(reopen_state->bs);
3784 if (ret) {
3785 error_setg_errno(errp, -ret, "Error flushing drive");
3786 goto error;
3787 }
3788
3789 if (drv->bdrv_reopen_prepare) {
3790 /*
3791 * If a driver-specific option is missing, it means that we
3792 * should reset it to its default value.
3793 * But not all options allow that, so we need to check it first.
3794 */
3795 ret = bdrv_reset_options_allowed(reopen_state->bs,
3796 reopen_state->options, errp);
3797 if (ret) {
3798 goto error;
3799 }
3800
3801 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err);
3802 if (ret) {
3803 if (local_err != NULL) {
3804 error_propagate(errp, local_err);
3805 } else {
3806 bdrv_refresh_filename(reopen_state->bs);
3807 error_setg(errp, "failed while preparing to reopen image '%s'",
3808 reopen_state->bs->filename);
3809 }
3810 goto error;
3811 }
3812 } else {
3813 /* It is currently mandatory to have a bdrv_reopen_prepare()
3814 * handler for each supported drv. */
3815 error_setg(errp, "Block format '%s' used by node '%s' "
3816 "does not support reopening files", drv->format_name,
3817 bdrv_get_device_or_node_name(reopen_state->bs));
3818 ret = -1;
3819 goto error;
3820 }
3821
3822 drv_prepared = true;
3823
3824 /*
3825 * We must provide the 'backing' option if the BDS has a backing
3826 * file or if the image file has a backing file name as part of
3827 * its metadata. Otherwise the 'backing' option can be omitted.
3828 */
3829 if (drv->supports_backing && reopen_state->backing_missing &&
3830 (backing_bs(reopen_state->bs) || reopen_state->bs->backing_file[0])) {
3831 error_setg(errp, "backing is missing for '%s'",
3832 reopen_state->bs->node_name);
3833 ret = -EINVAL;
3834 goto error;
3835 }
3836
3837 /*
3838 * Allow changing the 'backing' option. The new value can be
3839 * either a reference to an existing node (using its node name)
3840 * or NULL to simply detach the current backing file.
3841 */
3842 ret = bdrv_reopen_parse_backing(reopen_state, errp);
3843 if (ret < 0) {
3844 goto error;
3845 }
3846 qdict_del(reopen_state->options, "backing");
3847
3848 /* Options that are not handled are only okay if they are unchanged
3849 * compared to the old state. It is expected that some options are only
3850 * used for the initial open, but not reopen (e.g. filename) */
3851 if (qdict_size(reopen_state->options)) {
3852 const QDictEntry *entry = qdict_first(reopen_state->options);
3853
3854 do {
3855 QObject *new = entry->value;
3856 QObject *old = qdict_get(reopen_state->bs->options, entry->key);
3857
3858 /* Allow child references (child_name=node_name) as long as they
3859 * point to the current child (i.e. everything stays the same). */
3860 if (qobject_type(new) == QTYPE_QSTRING) {
3861 BdrvChild *child;
3862 QLIST_FOREACH(child, &reopen_state->bs->children, next) {
3863 if (!strcmp(child->name, entry->key)) {
3864 break;
3865 }
3866 }
3867
3868 if (child) {
3869 const char *str = qobject_get_try_str(new);
3870 if (!strcmp(child->bs->node_name, str)) {
3871 continue; /* Found child with this name, skip option */
3872 }
3873 }
3874 }
3875
3876 /*
3877 * TODO: When using -drive to specify blockdev options, all values
3878 * will be strings; however, when using -blockdev, blockdev-add or
3879 * filenames using the json:{} pseudo-protocol, they will be
3880 * correctly typed.
3881 * In contrast, reopening options are (currently) always strings
3882 * (because you can only specify them through qemu-io; all other
3883 * callers do not specify any options).
3884 * Therefore, when using anything other than -drive to create a BDS,
3885 * this cannot detect non-string options as unchanged, because
3886 * qobject_is_equal() always returns false for objects of different
3887 * type. In the future, this should be remedied by correctly typing
3888 * all options. For now, this is not too big of an issue because
3889 * the user can simply omit options which cannot be changed anyway,
3890 * so they will stay unchanged.
3891 */
3892 if (!qobject_is_equal(new, old)) {
3893 error_setg(errp, "Cannot change the option '%s'", entry->key);
3894 ret = -EINVAL;
3895 goto error;
3896 }
3897 } while ((entry = qdict_next(reopen_state->options, entry)));
3898 }
3899
3900 ret = 0;
3901
3902 /* Restore the original reopen_state->options QDict */
3903 qobject_unref(reopen_state->options);
3904 reopen_state->options = qobject_ref(orig_reopen_opts);
3905
3906error:
3907 if (ret < 0 && drv_prepared) {
3908 /* drv->bdrv_reopen_prepare() has succeeded, so we need to
3909 * call drv->bdrv_reopen_abort() before signaling an error
3910 * (bdrv_reopen_multiple() will not call bdrv_reopen_abort()
3911 * when the respective bdrv_reopen_prepare() has failed) */
3912 if (drv->bdrv_reopen_abort) {
3913 drv->bdrv_reopen_abort(reopen_state);
3914 }
3915 }
3916 qemu_opts_del(opts);
3917 qobject_unref(orig_reopen_opts);
3918 g_free(discard);
3919 return ret;
3920}
3921
3922/*
3923 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
3924 * makes them final by swapping the staging BlockDriverState contents into
3925 * the active BlockDriverState contents.
3926 */
3927void bdrv_reopen_commit(BDRVReopenState *reopen_state)
3928{
3929 BlockDriver *drv;
3930 BlockDriverState *bs;
3931 BdrvChild *child;
3932 bool old_can_write, new_can_write;
3933
3934 assert(reopen_state != NULL);
3935 bs = reopen_state->bs;
3936 drv = bs->drv;
3937 assert(drv != NULL);
3938
3939 old_can_write =
3940 !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE);
3941
3942 /* If there are any driver level actions to take */
3943 if (drv->bdrv_reopen_commit) {
3944 drv->bdrv_reopen_commit(reopen_state);
3945 }
3946
3947 /* set BDS specific flags now */
3948 qobject_unref(bs->explicit_options);
3949 qobject_unref(bs->options);
3950
3951 bs->explicit_options = reopen_state->explicit_options;
3952 bs->options = reopen_state->options;
3953 bs->open_flags = reopen_state->flags;
3954 bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
3955 bs->detect_zeroes = reopen_state->detect_zeroes;
3956
3957 if (reopen_state->replace_backing_bs) {
3958 qdict_del(bs->explicit_options, "backing");
3959 qdict_del(bs->options, "backing");
3960 }
3961
3962 /* Remove child references from bs->options and bs->explicit_options.
3963 * Child options were already removed in bdrv_reopen_queue_child() */
3964 QLIST_FOREACH(child, &bs->children, next) {
3965 qdict_del(bs->explicit_options, child->name);
3966 qdict_del(bs->options, child->name);
3967 }
3968
3969 /*
3970 * Change the backing file if a new one was specified. We do this
3971 * after updating bs->options, so bdrv_refresh_filename() (called
3972 * from bdrv_set_backing_hd()) has the new values.
3973 */
3974 if (reopen_state->replace_backing_bs) {
3975 BlockDriverState *old_backing_bs = backing_bs(bs);
3976 assert(!old_backing_bs || !old_backing_bs->implicit);
3977 /* Abort the permission update on the backing bs we're detaching */
3978 if (old_backing_bs) {
3979 bdrv_abort_perm_update(old_backing_bs);
3980 }
3981 bdrv_set_backing_hd(bs, reopen_state->new_backing_bs, &error_abort);
3982 }
3983
3984 bdrv_refresh_limits(bs, NULL);
3985
3986 new_can_write =
3987 !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE);
3988 if (!old_can_write && new_can_write && drv->bdrv_reopen_bitmaps_rw) {
3989 Error *local_err = NULL;
3990 if (drv->bdrv_reopen_bitmaps_rw(bs, &local_err) < 0) {
3991 /* This is not fatal, bitmaps just left read-only, so all following
3992 * writes will fail. User can remove read-only bitmaps to unblock
3993 * writes.
3994 */
3995 error_reportf_err(local_err,
3996 "%s: Failed to make dirty bitmaps writable: ",
3997 bdrv_get_node_name(bs));
3998 }
3999 }
4000}
4001
4002/*
4003 * Abort the reopen, and delete and free the staged changes in
4004 * reopen_state
4005 */
4006void bdrv_reopen_abort(BDRVReopenState *reopen_state)
4007{
4008 BlockDriver *drv;
4009
4010 assert(reopen_state != NULL);
4011 drv = reopen_state->bs->drv;
4012 assert(drv != NULL);
4013
4014 if (drv->bdrv_reopen_abort) {
4015 drv->bdrv_reopen_abort(reopen_state);
4016 }
4017}
4018
4019
4020static void bdrv_close(BlockDriverState *bs)
4021{
4022 BdrvAioNotifier *ban, *ban_next;
4023 BdrvChild *child, *next;
4024
4025 assert(!bs->refcnt);
4026
4027 bdrv_drained_begin(bs); /* complete I/O */
4028 bdrv_flush(bs);
4029 bdrv_drain(bs); /* in case flush left pending I/O */
4030
4031 if (bs->drv) {
4032 if (bs->drv->bdrv_close) {
4033 bs->drv->bdrv_close(bs);
4034 }
4035 bs->drv = NULL;
4036 }
4037
4038 QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
4039 bdrv_unref_child(bs, child);
4040 }
4041
4042 bs->backing = NULL;
4043 bs->file = NULL;
4044 g_free(bs->opaque);
4045 bs->opaque = NULL;
4046 atomic_set(&bs->copy_on_read, 0);
4047 bs->backing_file[0] = '\0';
4048 bs->backing_format[0] = '\0';
4049 bs->total_sectors = 0;
4050 bs->encrypted = false;
4051 bs->sg = false;
4052 qobject_unref(bs->options);
4053 qobject_unref(bs->explicit_options);
4054 bs->options = NULL;
4055 bs->explicit_options = NULL;
4056 qobject_unref(bs->full_open_options);
4057 bs->full_open_options = NULL;
4058
4059 bdrv_release_named_dirty_bitmaps(bs);
4060 assert(QLIST_EMPTY(&bs->dirty_bitmaps));
4061
4062 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
4063 g_free(ban);
4064 }
4065 QLIST_INIT(&bs->aio_notifiers);
4066 bdrv_drained_end(bs);
4067}
4068
4069void bdrv_close_all(void)
4070{
4071 assert(job_next(NULL) == NULL);
4072 nbd_export_close_all();
4073
4074 /* Drop references from requests still in flight, such as canceled block
4075 * jobs whose AIO context has not been polled yet */
4076 bdrv_drain_all();
4077
4078 blk_remove_all_bs();
4079 blockdev_close_all_bdrv_states();
4080
4081 assert(QTAILQ_EMPTY(&all_bdrv_states));
4082}
4083
4084static bool should_update_child(BdrvChild *c, BlockDriverState *to)
4085{
4086 GQueue *queue;
4087 GHashTable *found;
4088 bool ret;
4089
4090 if (c->role->stay_at_node) {
4091 return false;
4092 }
4093
4094 /* If the child @c belongs to the BDS @to, replacing the current
4095 * c->bs by @to would mean to create a loop.
4096 *
4097 * Such a case occurs when appending a BDS to a backing chain.
4098 * For instance, imagine the following chain:
4099 *
4100 * guest device -> node A -> further backing chain...
4101 *
4102 * Now we create a new BDS B which we want to put on top of this
4103 * chain, so we first attach A as its backing node:
4104 *
4105 * node B
4106 * |
4107 * v
4108 * guest device -> node A -> further backing chain...
4109 *
4110 * Finally we want to replace A by B. When doing that, we want to
4111 * replace all pointers to A by pointers to B -- except for the
4112 * pointer from B because (1) that would create a loop, and (2)
4113 * that pointer should simply stay intact:
4114 *
4115 * guest device -> node B
4116 * |
4117 * v
4118 * node A -> further backing chain...
4119 *
4120 * In general, when replacing a node A (c->bs) by a node B (@to),
4121 * if A is a child of B, that means we cannot replace A by B there
4122 * because that would create a loop. Silently detaching A from B
4123 * is also not really an option. So overall just leaving A in
4124 * place there is the most sensible choice.
4125 *
4126 * We would also create a loop in any cases where @c is only
4127 * indirectly referenced by @to. Prevent this by returning false
4128 * if @c is found (by breadth-first search) anywhere in the whole
4129 * subtree of @to.
4130 */
4131
4132 ret = true;
4133 found = g_hash_table_new(NULL, NULL);
4134 g_hash_table_add(found, to);
4135 queue = g_queue_new();
4136 g_queue_push_tail(queue, to);
4137
4138 while (!g_queue_is_empty(queue)) {
4139 BlockDriverState *v = g_queue_pop_head(queue);
4140 BdrvChild *c2;
4141
4142 QLIST_FOREACH(c2, &v->children, next) {
4143 if (c2 == c) {
4144 ret = false;
4145 break;
4146 }
4147
4148 if (g_hash_table_contains(found, c2->bs)) {
4149 continue;
4150 }
4151
4152 g_queue_push_tail(queue, c2->bs);
4153 g_hash_table_add(found, c2->bs);
4154 }
4155 }
4156
4157 g_queue_free(queue);
4158 g_hash_table_destroy(found);
4159
4160 return ret;
4161}
4162
4163void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
4164 Error **errp)
4165{
4166 BdrvChild *c, *next;
4167 GSList *list = NULL, *p;
4168 uint64_t perm = 0, shared = BLK_PERM_ALL;
4169 int ret;
4170
4171 /* Make sure that @from doesn't go away until we have successfully attached
4172 * all of its parents to @to. */
4173 bdrv_ref(from);
4174
4175 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
4176 bdrv_drained_begin(from);
4177
4178 /* Put all parents into @list and calculate their cumulative permissions */
4179 QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
4180 assert(c->bs == from);
4181 if (!should_update_child(c, to)) {
4182 continue;
4183 }
4184 if (c->frozen) {
4185 error_setg(errp, "Cannot change '%s' link to '%s'",
4186 c->name, from->node_name);
4187 goto out;
4188 }
4189 list = g_slist_prepend(list, c);
4190 perm |= c->perm;
4191 shared &= c->shared_perm;
4192 }
4193
4194 /* Check whether the required permissions can be granted on @to, ignoring
4195 * all BdrvChild in @list so that they can't block themselves. */
4196 ret = bdrv_check_update_perm(to, NULL, perm, shared, list, NULL, errp);
4197 if (ret < 0) {
4198 bdrv_abort_perm_update(to);
4199 goto out;
4200 }
4201
4202 /* Now actually perform the change. We performed the permission check for
4203 * all elements of @list at once, so set the permissions all at once at the
4204 * very end. */
4205 for (p = list; p != NULL; p = p->next) {
4206 c = p->data;
4207
4208 bdrv_ref(to);
4209 bdrv_replace_child_noperm(c, to);
4210 bdrv_unref(from);
4211 }
4212
4213 bdrv_get_cumulative_perm(to, &perm, &shared);
4214 bdrv_set_perm(to, perm, shared);
4215
4216out:
4217 g_slist_free(list);
4218 bdrv_drained_end(from);
4219 bdrv_unref(from);
4220}
4221
4222/*
4223 * Add new bs contents at the top of an image chain while the chain is
4224 * live, while keeping required fields on the top layer.
4225 *
4226 * This will modify the BlockDriverState fields, and swap contents
4227 * between bs_new and bs_top. Both bs_new and bs_top are modified.
4228 *
4229 * bs_new must not be attached to a BlockBackend.
4230 *
4231 * This function does not create any image files.
4232 *
4233 * bdrv_append() takes ownership of a bs_new reference and unrefs it because
4234 * that's what the callers commonly need. bs_new will be referenced by the old
4235 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a
4236 * reference of its own, it must call bdrv_ref().
4237 */
4238void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
4239 Error **errp)
4240{
4241 Error *local_err = NULL;
4242
4243 bdrv_set_backing_hd(bs_new, bs_top, &local_err);
4244 if (local_err) {
4245 error_propagate(errp, local_err);
4246 goto out;
4247 }
4248
4249 bdrv_replace_node(bs_top, bs_new, &local_err);
4250 if (local_err) {
4251 error_propagate(errp, local_err);
4252 bdrv_set_backing_hd(bs_new, NULL, &error_abort);
4253 goto out;
4254 }
4255
4256 /* bs_new is now referenced by its new parents, we don't need the
4257 * additional reference any more. */
4258out:
4259 bdrv_unref(bs_new);
4260}
4261
4262static void bdrv_delete(BlockDriverState *bs)
4263{
4264 assert(bdrv_op_blocker_is_empty(bs));
4265 assert(!bs->refcnt);
4266
4267 /* remove from list, if necessary */
4268 if (bs->node_name[0] != '\0') {
4269 QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list);
4270 }
4271 QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list);
4272
4273 bdrv_close(bs);
4274
4275 g_free(bs);
4276}
4277
4278/*
4279 * Run consistency checks on an image
4280 *
4281 * Returns 0 if the check could be completed (it doesn't mean that the image is
4282 * free of errors) or -errno when an internal error occurred. The results of the
4283 * check are stored in res.
4284 */
4285static int coroutine_fn bdrv_co_check(BlockDriverState *bs,
4286 BdrvCheckResult *res, BdrvCheckMode fix)
4287{
4288 if (bs->drv == NULL) {
4289 return -ENOMEDIUM;
4290 }
4291 if (bs->drv->bdrv_co_check == NULL) {
4292 return -ENOTSUP;
4293 }
4294
4295 memset(res, 0, sizeof(*res));
4296 return bs->drv->bdrv_co_check(bs, res, fix);
4297}
4298
4299typedef struct CheckCo {
4300 BlockDriverState *bs;
4301 BdrvCheckResult *res;
4302 BdrvCheckMode fix;
4303 int ret;
4304} CheckCo;
4305
4306static void coroutine_fn bdrv_check_co_entry(void *opaque)
4307{
4308 CheckCo *cco = opaque;
4309 cco->ret = bdrv_co_check(cco->bs, cco->res, cco->fix);
4310 aio_wait_kick();
4311}
4312
4313int bdrv_check(BlockDriverState *bs,
4314 BdrvCheckResult *res, BdrvCheckMode fix)
4315{
4316 Coroutine *co;
4317 CheckCo cco = {
4318 .bs = bs,
4319 .res = res,
4320 .ret = -EINPROGRESS,
4321 .fix = fix,
4322 };
4323
4324 if (qemu_in_coroutine()) {
4325 /* Fast-path if already in coroutine context */
4326 bdrv_check_co_entry(&cco);
4327 } else {
4328 co = qemu_coroutine_create(bdrv_check_co_entry, &cco);
4329 bdrv_coroutine_enter(bs, co);
4330 BDRV_POLL_WHILE(bs, cco.ret == -EINPROGRESS);
4331 }
4332
4333 return cco.ret;
4334}
4335
4336/*
4337 * Return values:
4338 * 0 - success
4339 * -EINVAL - backing format specified, but no file
4340 * -ENOSPC - can't update the backing file because no space is left in the
4341 * image file header
4342 * -ENOTSUP - format driver doesn't support changing the backing file
4343 */
4344int bdrv_change_backing_file(BlockDriverState *bs,
4345 const char *backing_file, const char *backing_fmt)
4346{
4347 BlockDriver *drv = bs->drv;
4348 int ret;
4349
4350 if (!drv) {
4351 return -ENOMEDIUM;
4352 }
4353
4354 /* Backing file format doesn't make sense without a backing file */
4355 if (backing_fmt && !backing_file) {
4356 return -EINVAL;
4357 }
4358
4359 if (drv->bdrv_change_backing_file != NULL) {
4360 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
4361 } else {
4362 ret = -ENOTSUP;
4363 }
4364
4365 if (ret == 0) {
4366 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
4367 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
4368 pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file),
4369 backing_file ?: "");
4370 }
4371 return ret;
4372}
4373
4374/*
4375 * Finds the image layer in the chain that has 'bs' as its backing file.
4376 *
4377 * active is the current topmost image.
4378 *
4379 * Returns NULL if bs is not found in active's image chain,
4380 * or if active == bs.
4381 *
4382 * Returns the bottommost base image if bs == NULL.
4383 */
4384BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
4385 BlockDriverState *bs)
4386{
4387 while (active && bs != backing_bs(active)) {
4388 active = backing_bs(active);
4389 }
4390
4391 return active;
4392}
4393
4394/* Given a BDS, searches for the base layer. */
4395BlockDriverState *bdrv_find_base(BlockDriverState *bs)
4396{
4397 return bdrv_find_overlay(bs, NULL);
4398}
4399
4400/*
4401 * Return true if at least one of the backing links between @bs and
4402 * @base is frozen. @errp is set if that's the case.
4403 * @base must be reachable from @bs, or NULL.
4404 */
4405bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
4406 Error **errp)
4407{
4408 BlockDriverState *i;
4409
4410 for (i = bs; i != base; i = backing_bs(i)) {
4411 if (i->backing && i->backing->frozen) {
4412 error_setg(errp, "Cannot change '%s' link from '%s' to '%s'",
4413 i->backing->name, i->node_name,
4414 backing_bs(i)->node_name);
4415 return true;
4416 }
4417 }
4418
4419 return false;
4420}
4421
4422/*
4423 * Freeze all backing links between @bs and @base.
4424 * If any of the links is already frozen the operation is aborted and
4425 * none of the links are modified.
4426 * @base must be reachable from @bs, or NULL.
4427 * Returns 0 on success. On failure returns < 0 and sets @errp.
4428 */
4429int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
4430 Error **errp)
4431{
4432 BlockDriverState *i;
4433
4434 if (bdrv_is_backing_chain_frozen(bs, base, errp)) {
4435 return -EPERM;
4436 }
4437
4438 for (i = bs; i != base; i = backing_bs(i)) {
4439 if (i->backing && backing_bs(i)->never_freeze) {
4440 error_setg(errp, "Cannot freeze '%s' link to '%s'",
4441 i->backing->name, backing_bs(i)->node_name);
4442 return -EPERM;
4443 }
4444 }
4445
4446 for (i = bs; i != base; i = backing_bs(i)) {
4447 if (i->backing) {
4448 i->backing->frozen = true;
4449 }
4450 }
4451
4452 return 0;
4453}
4454
4455/*
4456 * Unfreeze all backing links between @bs and @base. The caller must
4457 * ensure that all links are frozen before using this function.
4458 * @base must be reachable from @bs, or NULL.
4459 */
4460void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base)
4461{
4462 BlockDriverState *i;
4463
4464 for (i = bs; i != base; i = backing_bs(i)) {
4465 if (i->backing) {
4466 assert(i->backing->frozen);
4467 i->backing->frozen = false;
4468 }
4469 }
4470}
4471
4472/*
4473 * Drops images above 'base' up to and including 'top', and sets the image
4474 * above 'top' to have base as its backing file.
4475 *
4476 * Requires that the overlay to 'top' is opened r/w, so that the backing file
4477 * information in 'bs' can be properly updated.
4478 *
4479 * E.g., this will convert the following chain:
4480 * bottom <- base <- intermediate <- top <- active
4481 *
4482 * to
4483 *
4484 * bottom <- base <- active
4485 *
4486 * It is allowed for bottom==base, in which case it converts:
4487 *
4488 * base <- intermediate <- top <- active
4489 *
4490 * to
4491 *
4492 * base <- active
4493 *
4494 * If backing_file_str is non-NULL, it will be used when modifying top's
4495 * overlay image metadata.
4496 *
4497 * Error conditions:
4498 * if active == top, that is considered an error
4499 *
4500 */
4501int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
4502 const char *backing_file_str)
4503{
4504 BlockDriverState *explicit_top = top;
4505 bool update_inherits_from;
4506 BdrvChild *c, *next;
4507 Error *local_err = NULL;
4508 int ret = -EIO;
4509
4510 bdrv_ref(top);
4511 bdrv_subtree_drained_begin(top);
4512
4513 if (!top->drv || !base->drv) {
4514 goto exit;
4515 }
4516
4517 /* Make sure that base is in the backing chain of top */
4518 if (!bdrv_chain_contains(top, base)) {
4519 goto exit;
4520 }
4521
4522 /* This function changes all links that point to top and makes
4523 * them point to base. Check that none of them is frozen. */
4524 QLIST_FOREACH(c, &top->parents, next_parent) {
4525 if (c->frozen) {
4526 goto exit;
4527 }
4528 }
4529
4530 /* If 'base' recursively inherits from 'top' then we should set
4531 * base->inherits_from to top->inherits_from after 'top' and all
4532 * other intermediate nodes have been dropped.
4533 * If 'top' is an implicit node (e.g. "commit_top") we should skip
4534 * it because no one inherits from it. We use explicit_top for that. */
4535 while (explicit_top && explicit_top->implicit) {
4536 explicit_top = backing_bs(explicit_top);
4537 }
4538 update_inherits_from = bdrv_inherits_from_recursive(base, explicit_top);
4539
4540 /* success - we can delete the intermediate states, and link top->base */
4541 /* TODO Check graph modification op blockers (BLK_PERM_GRAPH_MOD) once
4542 * we've figured out how they should work. */
4543 if (!backing_file_str) {
4544 bdrv_refresh_filename(base);
4545 backing_file_str = base->filename;
4546 }
4547
4548 QLIST_FOREACH_SAFE(c, &top->parents, next_parent, next) {
4549 /* Check whether we are allowed to switch c from top to base */
4550 GSList *ignore_children = g_slist_prepend(NULL, c);
4551 ret = bdrv_check_update_perm(base, NULL, c->perm, c->shared_perm,
4552 ignore_children, NULL, &local_err);
4553 g_slist_free(ignore_children);
4554 if (ret < 0) {
4555 error_report_err(local_err);
4556 goto exit;
4557 }
4558
4559 /* If so, update the backing file path in the image file */
4560 if (c->role->update_filename) {
4561 ret = c->role->update_filename(c, base, backing_file_str,
4562 &local_err);
4563 if (ret < 0) {
4564 bdrv_abort_perm_update(base);
4565 error_report_err(local_err);
4566 goto exit;
4567 }
4568 }
4569
4570 /* Do the actual switch in the in-memory graph.
4571 * Completes bdrv_check_update_perm() transaction internally. */
4572 bdrv_ref(base);
4573 bdrv_replace_child(c, base);
4574 bdrv_unref(top);
4575 }
4576
4577 if (update_inherits_from) {
4578 base->inherits_from = explicit_top->inherits_from;
4579 }
4580
4581 ret = 0;
4582exit:
4583 bdrv_subtree_drained_end(top);
4584 bdrv_unref(top);
4585 return ret;
4586}
4587
4588/**
4589 * Length of a allocated file in bytes. Sparse files are counted by actual
4590 * allocated space. Return < 0 if error or unknown.
4591 */
4592int64_t bdrv_get_allocated_file_size(BlockDriverState *bs)
4593{
4594 BlockDriver *drv = bs->drv;
4595 if (!drv) {
4596 return -ENOMEDIUM;
4597 }
4598 if (drv->bdrv_get_allocated_file_size) {
4599 return drv->bdrv_get_allocated_file_size(bs);
4600 }
4601 if (bs->file) {
4602 return bdrv_get_allocated_file_size(bs->file->bs);
4603 }
4604 return -ENOTSUP;
4605}
4606
4607/*
4608 * bdrv_measure:
4609 * @drv: Format driver
4610 * @opts: Creation options for new image
4611 * @in_bs: Existing image containing data for new image (may be NULL)
4612 * @errp: Error object
4613 * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo())
4614 * or NULL on error
4615 *
4616 * Calculate file size required to create a new image.
4617 *
4618 * If @in_bs is given then space for allocated clusters and zero clusters
4619 * from that image are included in the calculation. If @opts contains a
4620 * backing file that is shared by @in_bs then backing clusters may be omitted
4621 * from the calculation.
4622 *
4623 * If @in_bs is NULL then the calculation includes no allocated clusters
4624 * unless a preallocation option is given in @opts.
4625 *
4626 * Note that @in_bs may use a different BlockDriver from @drv.
4627 *
4628 * If an error occurs the @errp pointer is set.
4629 */
4630BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
4631 BlockDriverState *in_bs, Error **errp)
4632{
4633 if (!drv->bdrv_measure) {
4634 error_setg(errp, "Block driver '%s' does not support size measurement",
4635 drv->format_name);
4636 return NULL;
4637 }
4638
4639 return drv->bdrv_measure(opts, in_bs, errp);
4640}
4641
4642/**
4643 * Return number of sectors on success, -errno on error.
4644 */
4645int64_t bdrv_nb_sectors(BlockDriverState *bs)
4646{
4647 BlockDriver *drv = bs->drv;
4648
4649 if (!drv)
4650 return -ENOMEDIUM;
4651
4652 if (drv->has_variable_length) {
4653 int ret = refresh_total_sectors(bs, bs->total_sectors);
4654 if (ret < 0) {
4655 return ret;
4656 }
4657 }
4658 return bs->total_sectors;
4659}
4660
4661/**
4662 * Return length in bytes on success, -errno on error.
4663 * The length is always a multiple of BDRV_SECTOR_SIZE.
4664 */
4665int64_t bdrv_getlength(BlockDriverState *bs)
4666{
4667 int64_t ret = bdrv_nb_sectors(bs);
4668
4669 ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret;
4670 return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE;
4671}
4672
4673/* return 0 as number of sectors if no device present or error */
4674void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
4675{
4676 int64_t nb_sectors = bdrv_nb_sectors(bs);
4677
4678 *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors;
4679}
4680
4681bool bdrv_is_sg(BlockDriverState *bs)
4682{
4683 return bs->sg;
4684}
4685
4686bool bdrv_is_encrypted(BlockDriverState *bs)
4687{
4688 if (bs->backing && bs->backing->bs->encrypted) {
4689 return true;
4690 }
4691 return bs->encrypted;
4692}
4693
4694const char *bdrv_get_format_name(BlockDriverState *bs)
4695{
4696 return bs->drv ? bs->drv->format_name : NULL;
4697}
4698
4699static int qsort_strcmp(const void *a, const void *b)
4700{
4701 return strcmp(*(char *const *)a, *(char *const *)b);
4702}
4703
4704void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
4705 void *opaque, bool read_only)
4706{
4707 BlockDriver *drv;
4708 int count = 0;
4709 int i;
4710 const char **formats = NULL;
4711
4712 QLIST_FOREACH(drv, &bdrv_drivers, list) {
4713 if (drv->format_name) {
4714 bool found = false;
4715 int i = count;
4716
4717 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, read_only)) {
4718 continue;
4719 }
4720
4721 while (formats && i && !found) {
4722 found = !strcmp(formats[--i], drv->format_name);
4723 }
4724
4725 if (!found) {
4726 formats = g_renew(const char *, formats, count + 1);
4727 formats[count++] = drv->format_name;
4728 }
4729 }
4730 }
4731
4732 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); i++) {
4733 const char *format_name = block_driver_modules[i].format_name;
4734
4735 if (format_name) {
4736 bool found = false;
4737 int j = count;
4738
4739 if (use_bdrv_whitelist &&
4740 !bdrv_format_is_whitelisted(format_name, read_only)) {
4741 continue;
4742 }
4743
4744 while (formats && j && !found) {
4745 found = !strcmp(formats[--j], format_name);
4746 }
4747
4748 if (!found) {
4749 formats = g_renew(const char *, formats, count + 1);
4750 formats[count++] = format_name;
4751 }
4752 }
4753 }
4754
4755 qsort(formats, count, sizeof(formats[0]), qsort_strcmp);
4756
4757 for (i = 0; i < count; i++) {
4758 it(opaque, formats[i]);
4759 }
4760
4761 g_free(formats);
4762}
4763
4764/* This function is to find a node in the bs graph */
4765BlockDriverState *bdrv_find_node(const char *node_name)
4766{
4767 BlockDriverState *bs;
4768
4769 assert(node_name);
4770
4771 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
4772 if (!strcmp(node_name, bs->node_name)) {
4773 return bs;
4774 }
4775 }
4776 return NULL;
4777}
4778
4779/* Put this QMP function here so it can access the static graph_bdrv_states. */
4780BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp)
4781{
4782 BlockDeviceInfoList *list, *entry;
4783 BlockDriverState *bs;
4784
4785 list = NULL;
4786 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
4787 BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, errp);
4788 if (!info) {
4789 qapi_free_BlockDeviceInfoList(list);
4790 return NULL;
4791 }
4792 entry = g_malloc0(sizeof(*entry));
4793 entry->value = info;
4794 entry->next = list;
4795 list = entry;
4796 }
4797
4798 return list;
4799}
4800
4801#define QAPI_LIST_ADD(list, element) do { \
4802 typeof(list) _tmp = g_new(typeof(*(list)), 1); \
4803 _tmp->value = (element); \
4804 _tmp->next = (list); \
4805 (list) = _tmp; \
4806} while (0)
4807
4808typedef struct XDbgBlockGraphConstructor {
4809 XDbgBlockGraph *graph;
4810 GHashTable *graph_nodes;
4811} XDbgBlockGraphConstructor;
4812
4813static XDbgBlockGraphConstructor *xdbg_graph_new(void)
4814{
4815 XDbgBlockGraphConstructor *gr = g_new(XDbgBlockGraphConstructor, 1);
4816
4817 gr->graph = g_new0(XDbgBlockGraph, 1);
4818 gr->graph_nodes = g_hash_table_new(NULL, NULL);
4819
4820 return gr;
4821}
4822
4823static XDbgBlockGraph *xdbg_graph_finalize(XDbgBlockGraphConstructor *gr)
4824{
4825 XDbgBlockGraph *graph = gr->graph;
4826
4827 g_hash_table_destroy(gr->graph_nodes);
4828 g_free(gr);
4829
4830 return graph;
4831}
4832
4833static uintptr_t xdbg_graph_node_num(XDbgBlockGraphConstructor *gr, void *node)
4834{
4835 uintptr_t ret = (uintptr_t)g_hash_table_lookup(gr->graph_nodes, node);
4836
4837 if (ret != 0) {
4838 return ret;
4839 }
4840
4841 /*
4842 * Start counting from 1, not 0, because 0 interferes with not-found (NULL)
4843 * answer of g_hash_table_lookup.
4844 */
4845 ret = g_hash_table_size(gr->graph_nodes) + 1;
4846 g_hash_table_insert(gr->graph_nodes, node, (void *)ret);
4847
4848 return ret;
4849}
4850
4851static void xdbg_graph_add_node(XDbgBlockGraphConstructor *gr, void *node,
4852 XDbgBlockGraphNodeType type, const char *name)
4853{
4854 XDbgBlockGraphNode *n;
4855
4856 n = g_new0(XDbgBlockGraphNode, 1);
4857
4858 n->id = xdbg_graph_node_num(gr, node);
4859 n->type = type;
4860 n->name = g_strdup(name);
4861
4862 QAPI_LIST_ADD(gr->graph->nodes, n);
4863}
4864
4865static void xdbg_graph_add_edge(XDbgBlockGraphConstructor *gr, void *parent,
4866 const BdrvChild *child)
4867{
4868 typedef struct {
4869 unsigned int flag;
4870 BlockPermission num;
4871 } PermissionMap;
4872
4873 static const PermissionMap permissions[] = {
4874 { BLK_PERM_CONSISTENT_READ, BLOCK_PERMISSION_CONSISTENT_READ },
4875 { BLK_PERM_WRITE, BLOCK_PERMISSION_WRITE },
4876 { BLK_PERM_WRITE_UNCHANGED, BLOCK_PERMISSION_WRITE_UNCHANGED },
4877 { BLK_PERM_RESIZE, BLOCK_PERMISSION_RESIZE },
4878 { BLK_PERM_GRAPH_MOD, BLOCK_PERMISSION_GRAPH_MOD },
4879 { 0, 0 }
4880 };
4881 const PermissionMap *p;
4882 XDbgBlockGraphEdge *edge;
4883
4884 QEMU_BUILD_BUG_ON(1UL << (ARRAY_SIZE(permissions) - 1) != BLK_PERM_ALL + 1);
4885
4886 edge = g_new0(XDbgBlockGraphEdge, 1);
4887
4888 edge->parent = xdbg_graph_node_num(gr, parent);
4889 edge->child = xdbg_graph_node_num(gr, child->bs);
4890 edge->name = g_strdup(child->name);
4891
4892 for (p = permissions; p->flag; p++) {
4893 if (p->flag & child->perm) {
4894 QAPI_LIST_ADD(edge->perm, p->num);
4895 }
4896 if (p->flag & child->shared_perm) {
4897 QAPI_LIST_ADD(edge->shared_perm, p->num);
4898 }
4899 }
4900
4901 QAPI_LIST_ADD(gr->graph->edges, edge);
4902}
4903
4904
4905XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp)
4906{
4907 BlockBackend *blk;
4908 BlockJob *job;
4909 BlockDriverState *bs;
4910 BdrvChild *child;
4911 XDbgBlockGraphConstructor *gr = xdbg_graph_new();
4912
4913 for (blk = blk_all_next(NULL); blk; blk = blk_all_next(blk)) {
4914 char *allocated_name = NULL;
4915 const char *name = blk_name(blk);
4916
4917 if (!*name) {
4918 name = allocated_name = blk_get_attached_dev_id(blk);
4919 }
4920 xdbg_graph_add_node(gr, blk, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND,
4921 name);
4922 g_free(allocated_name);
4923 if (blk_root(blk)) {
4924 xdbg_graph_add_edge(gr, blk, blk_root(blk));
4925 }
4926 }
4927
4928 for (job = block_job_next(NULL); job; job = block_job_next(job)) {
4929 GSList *el;
4930
4931 xdbg_graph_add_node(gr, job, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB,
4932 job->job.id);
4933 for (el = job->nodes; el; el = el->next) {
4934 xdbg_graph_add_edge(gr, job, (BdrvChild *)el->data);
4935 }
4936 }
4937
4938 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
4939 xdbg_graph_add_node(gr, bs, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_DRIVER,
4940 bs->node_name);
4941 QLIST_FOREACH(child, &bs->children, next) {
4942 xdbg_graph_add_edge(gr, bs, child);
4943 }
4944 }
4945
4946 return xdbg_graph_finalize(gr);
4947}
4948
4949BlockDriverState *bdrv_lookup_bs(const char *device,
4950 const char *node_name,
4951 Error **errp)
4952{
4953 BlockBackend *blk;
4954 BlockDriverState *bs;
4955
4956 if (device) {
4957 blk = blk_by_name(device);
4958
4959 if (blk) {
4960 bs = blk_bs(blk);
4961 if (!bs) {
4962 error_setg(errp, "Device '%s' has no medium", device);
4963 }
4964
4965 return bs;
4966 }
4967 }
4968
4969 if (node_name) {
4970 bs = bdrv_find_node(node_name);
4971
4972 if (bs) {
4973 return bs;
4974 }
4975 }
4976
4977 error_setg(errp, "Cannot find device=%s nor node_name=%s",
4978 device ? device : "",
4979 node_name ? node_name : "");
4980 return NULL;
4981}
4982
4983/* If 'base' is in the same chain as 'top', return true. Otherwise,
4984 * return false. If either argument is NULL, return false. */
4985bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base)
4986{
4987 while (top && top != base) {
4988 top = backing_bs(top);
4989 }
4990
4991 return top != NULL;
4992}
4993
4994BlockDriverState *bdrv_next_node(BlockDriverState *bs)
4995{
4996 if (!bs) {
4997 return QTAILQ_FIRST(&graph_bdrv_states);
4998 }
4999 return QTAILQ_NEXT(bs, node_list);
5000}
5001
5002BlockDriverState *bdrv_next_all_states(BlockDriverState *bs)
5003{
5004 if (!bs) {
5005 return QTAILQ_FIRST(&all_bdrv_states);
5006 }
5007 return QTAILQ_NEXT(bs, bs_list);
5008}
5009
5010const char *bdrv_get_node_name(const BlockDriverState *bs)
5011{
5012 return bs->node_name;
5013}
5014
5015const char *bdrv_get_parent_name(const BlockDriverState *bs)
5016{
5017 BdrvChild *c;
5018 const char *name;
5019
5020 /* If multiple parents have a name, just pick the first one. */
5021 QLIST_FOREACH(c, &bs->parents, next_parent) {
5022 if (c->role->get_name) {
5023 name = c->role->get_name(c);
5024 if (name && *name) {
5025 return name;
5026 }
5027 }
5028 }
5029
5030 return NULL;
5031}
5032
5033/* TODO check what callers really want: bs->node_name or blk_name() */
5034const char *bdrv_get_device_name(const BlockDriverState *bs)
5035{
5036 return bdrv_get_parent_name(bs) ?: "";
5037}
5038
5039/* This can be used to identify nodes that might not have a device
5040 * name associated. Since node and device names live in the same
5041 * namespace, the result is unambiguous. The exception is if both are
5042 * absent, then this returns an empty (non-null) string. */
5043const char *bdrv_get_device_or_node_name(const BlockDriverState *bs)
5044{
5045 return bdrv_get_parent_name(bs) ?: bs->node_name;
5046}
5047
5048int bdrv_get_flags(BlockDriverState *bs)
5049{
5050 return bs->open_flags;
5051}
5052
5053int bdrv_has_zero_init_1(BlockDriverState *bs)
5054{
5055 return 1;
5056}
5057
5058int bdrv_has_zero_init(BlockDriverState *bs)
5059{
5060 if (!bs->drv) {
5061 return 0;
5062 }
5063
5064 /* If BS is a copy on write image, it is initialized to
5065 the contents of the base image, which may not be zeroes. */
5066 if (bs->backing) {
5067 return 0;
5068 }
5069 if (bs->drv->bdrv_has_zero_init) {
5070 return bs->drv->bdrv_has_zero_init(bs);
5071 }
5072 if (bs->file && bs->drv->is_filter) {
5073 return bdrv_has_zero_init(bs->file->bs);
5074 }
5075
5076 /* safe default */
5077 return 0;
5078}
5079
5080int bdrv_has_zero_init_truncate(BlockDriverState *bs)
5081{
5082 if (!bs->drv) {
5083 return 0;
5084 }
5085
5086 if (bs->backing) {
5087 /* Depends on the backing image length, but better safe than sorry */
5088 return 0;
5089 }
5090 if (bs->drv->bdrv_has_zero_init_truncate) {
5091 return bs->drv->bdrv_has_zero_init_truncate(bs);
5092 }
5093 if (bs->file && bs->drv->is_filter) {
5094 return bdrv_has_zero_init_truncate(bs->file->bs);
5095 }
5096
5097 /* safe default */
5098 return 0;
5099}
5100
5101bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs)
5102{
5103 BlockDriverInfo bdi;
5104
5105 if (bs->backing) {
5106 return false;
5107 }
5108
5109 if (bdrv_get_info(bs, &bdi) == 0) {
5110 return bdi.unallocated_blocks_are_zero;
5111 }
5112
5113 return false;
5114}
5115
5116bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
5117{
5118 if (!(bs->open_flags & BDRV_O_UNMAP)) {
5119 return false;
5120 }
5121
5122 return bs->supported_zero_flags & BDRV_REQ_MAY_UNMAP;
5123}
5124
5125void bdrv_get_backing_filename(BlockDriverState *bs,
5126 char *filename, int filename_size)
5127{
5128 pstrcpy(filename, filename_size, bs->backing_file);
5129}
5130
5131int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
5132{
5133 BlockDriver *drv = bs->drv;
5134 /* if bs->drv == NULL, bs is closed, so there's nothing to do here */
5135 if (!drv) {
5136 return -ENOMEDIUM;
5137 }
5138 if (!drv->bdrv_get_info) {
5139 if (bs->file && drv->is_filter) {
5140 return bdrv_get_info(bs->file->bs, bdi);
5141 }
5142 return -ENOTSUP;
5143 }
5144 memset(bdi, 0, sizeof(*bdi));
5145 return drv->bdrv_get_info(bs, bdi);
5146}
5147
5148ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
5149 Error **errp)
5150{
5151 BlockDriver *drv = bs->drv;
5152 if (drv && drv->bdrv_get_specific_info) {
5153 return drv->bdrv_get_specific_info(bs, errp);
5154 }
5155 return NULL;
5156}
5157
5158void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event)
5159{
5160 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
5161 return;
5162 }
5163
5164 bs->drv->bdrv_debug_event(bs, event);
5165}
5166
5167int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
5168 const char *tag)
5169{
5170 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) {
5171 bs = bs->file ? bs->file->bs : NULL;
5172 }
5173
5174 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) {
5175 return bs->drv->bdrv_debug_breakpoint(bs, event, tag);
5176 }
5177
5178 return -ENOTSUP;
5179}
5180
5181int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag)
5182{
5183 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) {
5184 bs = bs->file ? bs->file->bs : NULL;
5185 }
5186
5187 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) {
5188 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag);
5189 }
5190
5191 return -ENOTSUP;
5192}
5193
5194int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
5195{
5196 while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) {
5197 bs = bs->file ? bs->file->bs : NULL;
5198 }
5199
5200 if (bs && bs->drv && bs->drv->bdrv_debug_resume) {
5201 return bs->drv->bdrv_debug_resume(bs, tag);
5202 }
5203
5204 return -ENOTSUP;
5205}
5206
5207bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag)
5208{
5209 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) {
5210 bs = bs->file ? bs->file->bs : NULL;
5211 }
5212
5213 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) {
5214 return bs->drv->bdrv_debug_is_suspended(bs, tag);
5215 }
5216
5217 return false;
5218}
5219
5220/* backing_file can either be relative, or absolute, or a protocol. If it is
5221 * relative, it must be relative to the chain. So, passing in bs->filename
5222 * from a BDS as backing_file should not be done, as that may be relative to
5223 * the CWD rather than the chain. */
5224BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
5225 const char *backing_file)
5226{
5227 char *filename_full = NULL;
5228 char *backing_file_full = NULL;
5229 char *filename_tmp = NULL;
5230 int is_protocol = 0;
5231 BlockDriverState *curr_bs = NULL;
5232 BlockDriverState *retval = NULL;
5233
5234 if (!bs || !bs->drv || !backing_file) {
5235 return NULL;
5236 }
5237
5238 filename_full = g_malloc(PATH_MAX);
5239 backing_file_full = g_malloc(PATH_MAX);
5240
5241 is_protocol = path_has_protocol(backing_file);
5242
5243 for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) {
5244
5245 /* If either of the filename paths is actually a protocol, then
5246 * compare unmodified paths; otherwise make paths relative */
5247 if (is_protocol || path_has_protocol(curr_bs->backing_file)) {
5248 char *backing_file_full_ret;
5249
5250 if (strcmp(backing_file, curr_bs->backing_file) == 0) {
5251 retval = curr_bs->backing->bs;
5252 break;
5253 }
5254 /* Also check against the full backing filename for the image */
5255 backing_file_full_ret = bdrv_get_full_backing_filename(curr_bs,
5256 NULL);
5257 if (backing_file_full_ret) {
5258 bool equal = strcmp(backing_file, backing_file_full_ret) == 0;
5259 g_free(backing_file_full_ret);
5260 if (equal) {
5261 retval = curr_bs->backing->bs;
5262 break;
5263 }
5264 }
5265 } else {
5266 /* If not an absolute filename path, make it relative to the current
5267 * image's filename path */
5268 filename_tmp = bdrv_make_absolute_filename(curr_bs, backing_file,
5269 NULL);
5270 /* We are going to compare canonicalized absolute pathnames */
5271 if (!filename_tmp || !realpath(filename_tmp, filename_full)) {
5272 g_free(filename_tmp);
5273 continue;
5274 }
5275 g_free(filename_tmp);
5276
5277 /* We need to make sure the backing filename we are comparing against
5278 * is relative to the current image filename (or absolute) */
5279 filename_tmp = bdrv_get_full_backing_filename(curr_bs, NULL);
5280 if (!filename_tmp || !realpath(filename_tmp, backing_file_full)) {
5281 g_free(filename_tmp);
5282 continue;
5283 }
5284 g_free(filename_tmp);
5285
5286 if (strcmp(backing_file_full, filename_full) == 0) {
5287 retval = curr_bs->backing->bs;
5288 break;
5289 }
5290 }
5291 }
5292
5293 g_free(filename_full);
5294 g_free(backing_file_full);
5295 return retval;
5296}
5297
5298void bdrv_init(void)
5299{
5300 module_call_init(MODULE_INIT_BLOCK);
5301}
5302
5303void bdrv_init_with_whitelist(void)
5304{
5305 use_bdrv_whitelist = 1;
5306 bdrv_init();
5307}
5308
5309static void coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs,
5310 Error **errp)
5311{
5312 BdrvChild *child, *parent;
5313 uint64_t perm, shared_perm;
5314 Error *local_err = NULL;
5315 int ret;
5316 BdrvDirtyBitmap *bm;
5317
5318 if (!bs->drv) {
5319 return;
5320 }
5321
5322 if (!(bs->open_flags & BDRV_O_INACTIVE)) {
5323 return;
5324 }
5325
5326 QLIST_FOREACH(child, &bs->children, next) {
5327 bdrv_co_invalidate_cache(child->bs, &local_err);
5328 if (local_err) {
5329 error_propagate(errp, local_err);
5330 return;
5331 }
5332 }
5333
5334 /*
5335 * Update permissions, they may differ for inactive nodes.
5336 *
5337 * Note that the required permissions of inactive images are always a
5338 * subset of the permissions required after activating the image. This
5339 * allows us to just get the permissions upfront without restricting
5340 * drv->bdrv_invalidate_cache().
5341 *
5342 * It also means that in error cases, we don't have to try and revert to
5343 * the old permissions (which is an operation that could fail, too). We can
5344 * just keep the extended permissions for the next time that an activation
5345 * of the image is tried.
5346 */
5347 bs->open_flags &= ~BDRV_O_INACTIVE;
5348 bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
5349 ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, NULL, &local_err);
5350 if (ret < 0) {
5351 bs->open_flags |= BDRV_O_INACTIVE;
5352 error_propagate(errp, local_err);
5353 return;
5354 }
5355 bdrv_set_perm(bs, perm, shared_perm);
5356
5357 if (bs->drv->bdrv_co_invalidate_cache) {
5358 bs->drv->bdrv_co_invalidate_cache(bs, &local_err);
5359 if (local_err) {
5360 bs->open_flags |= BDRV_O_INACTIVE;
5361 error_propagate(errp, local_err);
5362 return;
5363 }
5364 }
5365
5366 for (bm = bdrv_dirty_bitmap_next(bs, NULL); bm;
5367 bm = bdrv_dirty_bitmap_next(bs, bm))
5368 {
5369 bdrv_dirty_bitmap_skip_store(bm, false);
5370 }
5371
5372 ret = refresh_total_sectors(bs, bs->total_sectors);
5373 if (ret < 0) {
5374 bs->open_flags |= BDRV_O_INACTIVE;
5375 error_setg_errno(errp, -ret, "Could not refresh total sector count");
5376 return;
5377 }
5378
5379 QLIST_FOREACH(parent, &bs->parents, next_parent) {
5380 if (parent->role->activate) {
5381 parent->role->activate(parent, &local_err);
5382 if (local_err) {
5383 bs->open_flags |= BDRV_O_INACTIVE;
5384 error_propagate(errp, local_err);
5385 return;
5386 }
5387 }
5388 }
5389}
5390
5391typedef struct InvalidateCacheCo {
5392 BlockDriverState *bs;
5393 Error **errp;
5394 bool done;
5395} InvalidateCacheCo;
5396
5397static void coroutine_fn bdrv_invalidate_cache_co_entry(void *opaque)
5398{
5399 InvalidateCacheCo *ico = opaque;
5400 bdrv_co_invalidate_cache(ico->bs, ico->errp);
5401 ico->done = true;
5402 aio_wait_kick();
5403}
5404
5405void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
5406{
5407 Coroutine *co;
5408 InvalidateCacheCo ico = {
5409 .bs = bs,
5410 .done = false,
5411 .errp = errp
5412 };
5413
5414 if (qemu_in_coroutine()) {
5415 /* Fast-path if already in coroutine context */
5416 bdrv_invalidate_cache_co_entry(&ico);
5417 } else {
5418 co = qemu_coroutine_create(bdrv_invalidate_cache_co_entry, &ico);
5419 bdrv_coroutine_enter(bs, co);
5420 BDRV_POLL_WHILE(bs, !ico.done);
5421 }
5422}
5423
5424void bdrv_invalidate_cache_all(Error **errp)
5425{
5426 BlockDriverState *bs;
5427 Error *local_err = NULL;
5428 BdrvNextIterator it;
5429
5430 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
5431 AioContext *aio_context = bdrv_get_aio_context(bs);
5432
5433 aio_context_acquire(aio_context);
5434 bdrv_invalidate_cache(bs, &local_err);
5435 aio_context_release(aio_context);
5436 if (local_err) {
5437 error_propagate(errp, local_err);
5438 bdrv_next_cleanup(&it);
5439 return;
5440 }
5441 }
5442}
5443
5444static bool bdrv_has_bds_parent(BlockDriverState *bs, bool only_active)
5445{
5446 BdrvChild *parent;
5447
5448 QLIST_FOREACH(parent, &bs->parents, next_parent) {
5449 if (parent->role->parent_is_bds) {
5450 BlockDriverState *parent_bs = parent->opaque;
5451 if (!only_active || !(parent_bs->open_flags & BDRV_O_INACTIVE)) {
5452 return true;
5453 }
5454 }
5455 }
5456
5457 return false;
5458}
5459
5460static int bdrv_inactivate_recurse(BlockDriverState *bs)
5461{
5462 BdrvChild *child, *parent;
5463 bool tighten_restrictions;
5464 uint64_t perm, shared_perm;
5465 int ret;
5466
5467 if (!bs->drv) {
5468 return -ENOMEDIUM;
5469 }
5470
5471 /* Make sure that we don't inactivate a child before its parent.
5472 * It will be covered by recursion from the yet active parent. */
5473 if (bdrv_has_bds_parent(bs, true)) {
5474 return 0;
5475 }
5476
5477 assert(!(bs->open_flags & BDRV_O_INACTIVE));
5478
5479 /* Inactivate this node */
5480 if (bs->drv->bdrv_inactivate) {
5481 ret = bs->drv->bdrv_inactivate(bs);
5482 if (ret < 0) {
5483 return ret;
5484 }
5485 }
5486
5487 QLIST_FOREACH(parent, &bs->parents, next_parent) {
5488 if (parent->role->inactivate) {
5489 ret = parent->role->inactivate(parent);
5490 if (ret < 0) {
5491 return ret;
5492 }
5493 }
5494 }
5495
5496 bs->open_flags |= BDRV_O_INACTIVE;
5497
5498 /* Update permissions, they may differ for inactive nodes */
5499 bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
5500 ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL,
5501 &tighten_restrictions, NULL);
5502 assert(tighten_restrictions == false);
5503 if (ret < 0) {
5504 /* We only tried to loosen restrictions, so errors are not fatal */
5505 bdrv_abort_perm_update(bs);
5506 } else {
5507 bdrv_set_perm(bs, perm, shared_perm);
5508 }
5509
5510
5511 /* Recursively inactivate children */
5512 QLIST_FOREACH(child, &bs->children, next) {
5513 ret = bdrv_inactivate_recurse(child->bs);
5514 if (ret < 0) {
5515 return ret;
5516 }
5517 }
5518
5519 return 0;
5520}
5521
5522int bdrv_inactivate_all(void)
5523{
5524 BlockDriverState *bs = NULL;
5525 BdrvNextIterator it;
5526 int ret = 0;
5527 GSList *aio_ctxs = NULL, *ctx;
5528
5529 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
5530 AioContext *aio_context = bdrv_get_aio_context(bs);
5531
5532 if (!g_slist_find(aio_ctxs, aio_context)) {
5533 aio_ctxs = g_slist_prepend(aio_ctxs, aio_context);
5534 aio_context_acquire(aio_context);
5535 }
5536 }
5537
5538 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
5539 /* Nodes with BDS parents are covered by recursion from the last
5540 * parent that gets inactivated. Don't inactivate them a second
5541 * time if that has already happened. */
5542 if (bdrv_has_bds_parent(bs, false)) {
5543 continue;
5544 }
5545 ret = bdrv_inactivate_recurse(bs);
5546 if (ret < 0) {
5547 bdrv_next_cleanup(&it);
5548 goto out;
5549 }
5550 }
5551
5552out:
5553 for (ctx = aio_ctxs; ctx != NULL; ctx = ctx->next) {
5554 AioContext *aio_context = ctx->data;
5555 aio_context_release(aio_context);
5556 }
5557 g_slist_free(aio_ctxs);
5558
5559 return ret;
5560}
5561
5562/**************************************************************/
5563/* removable device support */
5564
5565/**
5566 * Return TRUE if the media is present
5567 */
5568bool bdrv_is_inserted(BlockDriverState *bs)
5569{
5570 BlockDriver *drv = bs->drv;
5571 BdrvChild *child;
5572
5573 if (!drv) {
5574 return false;
5575 }
5576 if (drv->bdrv_is_inserted) {
5577 return drv->bdrv_is_inserted(bs);
5578 }
5579 QLIST_FOREACH(child, &bs->children, next) {
5580 if (!bdrv_is_inserted(child->bs)) {
5581 return false;
5582 }
5583 }
5584 return true;
5585}
5586
5587/**
5588 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
5589 */
5590void bdrv_eject(BlockDriverState *bs, bool eject_flag)
5591{
5592 BlockDriver *drv = bs->drv;
5593
5594 if (drv && drv->bdrv_eject) {
5595 drv->bdrv_eject(bs, eject_flag);
5596 }
5597}
5598
5599/**
5600 * Lock or unlock the media (if it is locked, the user won't be able
5601 * to eject it manually).
5602 */
5603void bdrv_lock_medium(BlockDriverState *bs, bool locked)
5604{
5605 BlockDriver *drv = bs->drv;
5606
5607 trace_bdrv_lock_medium(bs, locked);
5608
5609 if (drv && drv->bdrv_lock_medium) {
5610 drv->bdrv_lock_medium(bs, locked);
5611 }
5612}
5613
5614/* Get a reference to bs */
5615void bdrv_ref(BlockDriverState *bs)
5616{
5617 bs->refcnt++;
5618}
5619
5620/* Release a previously grabbed reference to bs.
5621 * If after releasing, reference count is zero, the BlockDriverState is
5622 * deleted. */
5623void bdrv_unref(BlockDriverState *bs)
5624{
5625 if (!bs) {
5626 return;
5627 }
5628 assert(bs->refcnt > 0);
5629 if (--bs->refcnt == 0) {
5630 bdrv_delete(bs);
5631 }
5632}
5633
5634struct BdrvOpBlocker {
5635 Error *reason;
5636 QLIST_ENTRY(BdrvOpBlocker) list;
5637};
5638
5639bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp)
5640{
5641 BdrvOpBlocker *blocker;
5642 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
5643 if (!QLIST_EMPTY(&bs->op_blockers[op])) {
5644 blocker = QLIST_FIRST(&bs->op_blockers[op]);
5645 error_propagate_prepend(errp, error_copy(blocker->reason),
5646 "Node '%s' is busy: ",
5647 bdrv_get_device_or_node_name(bs));
5648 return true;
5649 }
5650 return false;
5651}
5652
5653void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason)
5654{
5655 BdrvOpBlocker *blocker;
5656 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
5657
5658 blocker = g_new0(BdrvOpBlocker, 1);
5659 blocker->reason = reason;
5660 QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list);
5661}
5662
5663void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason)
5664{
5665 BdrvOpBlocker *blocker, *next;
5666 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
5667 QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) {
5668 if (blocker->reason == reason) {
5669 QLIST_REMOVE(blocker, list);
5670 g_free(blocker);
5671 }
5672 }
5673}
5674
5675void bdrv_op_block_all(BlockDriverState *bs, Error *reason)
5676{
5677 int i;
5678 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
5679 bdrv_op_block(bs, i, reason);
5680 }
5681}
5682
5683void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason)
5684{
5685 int i;
5686 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
5687 bdrv_op_unblock(bs, i, reason);
5688 }
5689}
5690
5691bool bdrv_op_blocker_is_empty(BlockDriverState *bs)
5692{
5693 int i;
5694
5695 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
5696 if (!QLIST_EMPTY(&bs->op_blockers[i])) {
5697 return false;
5698 }
5699 }
5700 return true;
5701}
5702
5703void bdrv_img_create(const char *filename, const char *fmt,
5704 const char *base_filename, const char *base_fmt,
5705 char *options, uint64_t img_size, int flags, bool quiet,
5706 Error **errp)
5707{
5708 QemuOptsList *create_opts = NULL;
5709 QemuOpts *opts = NULL;
5710 const char *backing_fmt, *backing_file;
5711 int64_t size;
5712 BlockDriver *drv, *proto_drv;
5713 Error *local_err = NULL;
5714 int ret = 0;
5715
5716 /* Find driver and parse its options */
5717 drv = bdrv_find_format(fmt);
5718 if (!drv) {
5719 error_setg(errp, "Unknown file format '%s'", fmt);
5720 return;
5721 }
5722
5723 proto_drv = bdrv_find_protocol(filename, true, errp);
5724 if (!proto_drv) {
5725 return;
5726 }
5727
5728 if (!drv->create_opts) {
5729 error_setg(errp, "Format driver '%s' does not support image creation",
5730 drv->format_name);
5731 return;
5732 }
5733
5734 if (!proto_drv->create_opts) {
5735 error_setg(errp, "Protocol driver '%s' does not support image creation",
5736 proto_drv->format_name);
5737 return;
5738 }
5739
5740 create_opts = qemu_opts_append(create_opts, drv->create_opts);
5741 create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
5742
5743 /* Create parameter list with default values */
5744 opts = qemu_opts_create(create_opts, NULL, 0, &error_abort);
5745 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, img_size, &error_abort);
5746
5747 /* Parse -o options */
5748 if (options) {
5749 qemu_opts_do_parse(opts, options, NULL, &local_err);
5750 if (local_err) {
5751 goto out;
5752 }
5753 }
5754
5755 if (base_filename) {
5756 qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename, &local_err);
5757 if (local_err) {
5758 error_setg(errp, "Backing file not supported for file format '%s'",
5759 fmt);
5760 goto out;
5761 }
5762 }
5763
5764 if (base_fmt) {
5765 qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt, &local_err);
5766 if (local_err) {
5767 error_setg(errp, "Backing file format not supported for file "
5768 "format '%s'", fmt);
5769 goto out;
5770 }
5771 }
5772
5773 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
5774 if (backing_file) {
5775 if (!strcmp(filename, backing_file)) {
5776 error_setg(errp, "Error: Trying to create an image with the "
5777 "same filename as the backing file");
5778 goto out;
5779 }
5780 }
5781
5782 backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
5783
5784 /* The size for the image must always be specified, unless we have a backing
5785 * file and we have not been forbidden from opening it. */
5786 size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, img_size);
5787 if (backing_file && !(flags & BDRV_O_NO_BACKING)) {
5788 BlockDriverState *bs;
5789 char *full_backing;
5790 int back_flags;
5791 QDict *backing_options = NULL;
5792
5793 full_backing =
5794 bdrv_get_full_backing_filename_from_filename(filename, backing_file,
5795 &local_err);
5796 if (local_err) {
5797 goto out;
5798 }
5799 assert(full_backing);
5800
5801 /* backing files always opened read-only */
5802 back_flags = flags;
5803 back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
5804
5805 backing_options = qdict_new();
5806 if (backing_fmt) {
5807 qdict_put_str(backing_options, "driver", backing_fmt);
5808 }
5809 qdict_put_bool(backing_options, BDRV_OPT_FORCE_SHARE, true);
5810
5811 bs = bdrv_open(full_backing, NULL, backing_options, back_flags,
5812 &local_err);
5813 g_free(full_backing);
5814 if (!bs && size != -1) {
5815 /* Couldn't open BS, but we have a size, so it's nonfatal */
5816 warn_reportf_err(local_err,
5817 "Could not verify backing image. "
5818 "This may become an error in future versions.\n");
5819 local_err = NULL;
5820 } else if (!bs) {
5821 /* Couldn't open bs, do not have size */
5822 error_append_hint(&local_err,
5823 "Could not open backing image to determine size.\n");
5824 goto out;
5825 } else {
5826 if (size == -1) {
5827 /* Opened BS, have no size */
5828 size = bdrv_getlength(bs);
5829 if (size < 0) {
5830 error_setg_errno(errp, -size, "Could not get size of '%s'",
5831 backing_file);
5832 bdrv_unref(bs);
5833 goto out;
5834 }
5835 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort);
5836 }
5837 bdrv_unref(bs);
5838 }
5839 } /* (backing_file && !(flags & BDRV_O_NO_BACKING)) */
5840
5841 if (size == -1) {
5842 error_setg(errp, "Image creation needs a size parameter");
5843 goto out;
5844 }
5845
5846 if (!quiet) {
5847 printf("Formatting '%s', fmt=%s ", filename, fmt);
5848 qemu_opts_print(opts, " ");
5849 puts("");
5850 }
5851
5852 ret = bdrv_create(drv, filename, opts, &local_err);
5853
5854 if (ret == -EFBIG) {
5855 /* This is generally a better message than whatever the driver would
5856 * deliver (especially because of the cluster_size_hint), since that
5857 * is most probably not much different from "image too large". */
5858 const char *cluster_size_hint = "";
5859 if (qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 0)) {
5860 cluster_size_hint = " (try using a larger cluster size)";
5861 }
5862 error_setg(errp, "The image size is too large for file format '%s'"
5863 "%s", fmt, cluster_size_hint);
5864 error_free(local_err);
5865 local_err = NULL;
5866 }
5867
5868out:
5869 qemu_opts_del(opts);
5870 qemu_opts_free(create_opts);
5871 error_propagate(errp, local_err);
5872}
5873
5874AioContext *bdrv_get_aio_context(BlockDriverState *bs)
5875{
5876 return bs ? bs->aio_context : qemu_get_aio_context();
5877}
5878
5879void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co)
5880{
5881 aio_co_enter(bdrv_get_aio_context(bs), co);
5882}
5883
5884static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban)
5885{
5886 QLIST_REMOVE(ban, list);
5887 g_free(ban);
5888}
5889
5890static void bdrv_detach_aio_context(BlockDriverState *bs)
5891{
5892 BdrvAioNotifier *baf, *baf_tmp;
5893
5894 assert(!bs->walking_aio_notifiers);
5895 bs->walking_aio_notifiers = true;
5896 QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) {
5897 if (baf->deleted) {
5898 bdrv_do_remove_aio_context_notifier(baf);
5899 } else {
5900 baf->detach_aio_context(baf->opaque);
5901 }
5902 }
5903 /* Never mind iterating again to check for ->deleted. bdrv_close() will
5904 * remove remaining aio notifiers if we aren't called again.
5905 */
5906 bs->walking_aio_notifiers = false;
5907
5908 if (bs->drv && bs->drv->bdrv_detach_aio_context) {
5909 bs->drv->bdrv_detach_aio_context(bs);
5910 }
5911
5912 if (bs->quiesce_counter) {
5913 aio_enable_external(bs->aio_context);
5914 }
5915 bs->aio_context = NULL;
5916}
5917
5918static void bdrv_attach_aio_context(BlockDriverState *bs,
5919 AioContext *new_context)
5920{
5921 BdrvAioNotifier *ban, *ban_tmp;
5922
5923 if (bs->quiesce_counter) {
5924 aio_disable_external(new_context);
5925 }
5926
5927 bs->aio_context = new_context;
5928
5929 if (bs->drv && bs->drv->bdrv_attach_aio_context) {
5930 bs->drv->bdrv_attach_aio_context(bs, new_context);
5931 }
5932
5933 assert(!bs->walking_aio_notifiers);
5934 bs->walking_aio_notifiers = true;
5935 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_tmp) {
5936 if (ban->deleted) {
5937 bdrv_do_remove_aio_context_notifier(ban);
5938 } else {
5939 ban->attached_aio_context(new_context, ban->opaque);
5940 }
5941 }
5942 bs->walking_aio_notifiers = false;
5943}
5944
5945/*
5946 * Changes the AioContext used for fd handlers, timers, and BHs by this
5947 * BlockDriverState and all its children and parents.
5948 *
5949 * Must be called from the main AioContext.
5950 *
5951 * The caller must own the AioContext lock for the old AioContext of bs, but it
5952 * must not own the AioContext lock for new_context (unless new_context is the
5953 * same as the current context of bs).
5954 *
5955 * @ignore will accumulate all visited BdrvChild object. The caller is
5956 * responsible for freeing the list afterwards.
5957 */
5958void bdrv_set_aio_context_ignore(BlockDriverState *bs,
5959 AioContext *new_context, GSList **ignore)
5960{
5961 AioContext *old_context = bdrv_get_aio_context(bs);
5962 BdrvChild *child;
5963
5964 g_assert(qemu_get_current_aio_context() == qemu_get_aio_context());
5965
5966 if (old_context == new_context) {
5967 return;
5968 }
5969
5970 bdrv_drained_begin(bs);
5971
5972 QLIST_FOREACH(child, &bs->children, next) {
5973 if (g_slist_find(*ignore, child)) {
5974 continue;
5975 }
5976 *ignore = g_slist_prepend(*ignore, child);
5977 bdrv_set_aio_context_ignore(child->bs, new_context, ignore);
5978 }
5979 QLIST_FOREACH(child, &bs->parents, next_parent) {
5980 if (g_slist_find(*ignore, child)) {
5981 continue;
5982 }
5983 assert(child->role->set_aio_ctx);
5984 *ignore = g_slist_prepend(*ignore, child);
5985 child->role->set_aio_ctx(child, new_context, ignore);
5986 }
5987
5988 bdrv_detach_aio_context(bs);
5989
5990 /* Acquire the new context, if necessary */
5991 if (qemu_get_aio_context() != new_context) {
5992 aio_context_acquire(new_context);
5993 }
5994
5995 bdrv_attach_aio_context(bs, new_context);
5996
5997 /*
5998 * If this function was recursively called from
5999 * bdrv_set_aio_context_ignore(), there may be nodes in the
6000 * subtree that have not yet been moved to the new AioContext.
6001 * Release the old one so bdrv_drained_end() can poll them.
6002 */
6003 if (qemu_get_aio_context() != old_context) {
6004 aio_context_release(old_context);
6005 }
6006
6007 bdrv_drained_end(bs);
6008
6009 if (qemu_get_aio_context() != old_context) {
6010 aio_context_acquire(old_context);
6011 }
6012 if (qemu_get_aio_context() != new_context) {
6013 aio_context_release(new_context);
6014 }
6015}
6016
6017static bool bdrv_parent_can_set_aio_context(BdrvChild *c, AioContext *ctx,
6018 GSList **ignore, Error **errp)
6019{
6020 if (g_slist_find(*ignore, c)) {
6021 return true;
6022 }
6023 *ignore = g_slist_prepend(*ignore, c);
6024
6025 /* A BdrvChildRole that doesn't handle AioContext changes cannot
6026 * tolerate any AioContext changes */
6027 if (!c->role->can_set_aio_ctx) {
6028 char *user = bdrv_child_user_desc(c);
6029 error_setg(errp, "Changing iothreads is not supported by %s", user);
6030 g_free(user);
6031 return false;
6032 }
6033 if (!c->role->can_set_aio_ctx(c, ctx, ignore, errp)) {
6034 assert(!errp || *errp);
6035 return false;
6036 }
6037 return true;
6038}
6039
6040bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx,
6041 GSList **ignore, Error **errp)
6042{
6043 if (g_slist_find(*ignore, c)) {
6044 return true;
6045 }
6046 *ignore = g_slist_prepend(*ignore, c);
6047 return bdrv_can_set_aio_context(c->bs, ctx, ignore, errp);
6048}
6049
6050/* @ignore will accumulate all visited BdrvChild object. The caller is
6051 * responsible for freeing the list afterwards. */
6052bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx,
6053 GSList **ignore, Error **errp)
6054{
6055 BdrvChild *c;
6056
6057 if (bdrv_get_aio_context(bs) == ctx) {
6058 return true;
6059 }
6060
6061 QLIST_FOREACH(c, &bs->parents, next_parent) {
6062 if (!bdrv_parent_can_set_aio_context(c, ctx, ignore, errp)) {
6063 return false;
6064 }
6065 }
6066 QLIST_FOREACH(c, &bs->children, next) {
6067 if (!bdrv_child_can_set_aio_context(c, ctx, ignore, errp)) {
6068 return false;
6069 }
6070 }
6071
6072 return true;
6073}
6074
6075int bdrv_child_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
6076 BdrvChild *ignore_child, Error **errp)
6077{
6078 GSList *ignore;
6079 bool ret;
6080
6081 ignore = ignore_child ? g_slist_prepend(NULL, ignore_child) : NULL;
6082 ret = bdrv_can_set_aio_context(bs, ctx, &ignore, errp);
6083 g_slist_free(ignore);
6084
6085 if (!ret) {
6086 return -EPERM;
6087 }
6088
6089 ignore = ignore_child ? g_slist_prepend(NULL, ignore_child) : NULL;
6090 bdrv_set_aio_context_ignore(bs, ctx, &ignore);
6091 g_slist_free(ignore);
6092
6093 return 0;
6094}
6095
6096int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
6097 Error **errp)
6098{
6099 return bdrv_child_try_set_aio_context(bs, ctx, NULL, errp);
6100}
6101
6102void bdrv_add_aio_context_notifier(BlockDriverState *bs,
6103 void (*attached_aio_context)(AioContext *new_context, void *opaque),
6104 void (*detach_aio_context)(void *opaque), void *opaque)
6105{
6106 BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1);
6107 *ban = (BdrvAioNotifier){
6108 .attached_aio_context = attached_aio_context,
6109 .detach_aio_context = detach_aio_context,
6110 .opaque = opaque
6111 };
6112
6113 QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list);
6114}
6115
6116void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
6117 void (*attached_aio_context)(AioContext *,
6118 void *),
6119 void (*detach_aio_context)(void *),
6120 void *opaque)
6121{
6122 BdrvAioNotifier *ban, *ban_next;
6123
6124 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
6125 if (ban->attached_aio_context == attached_aio_context &&
6126 ban->detach_aio_context == detach_aio_context &&
6127 ban->opaque == opaque &&
6128 ban->deleted == false)
6129 {
6130 if (bs->walking_aio_notifiers) {
6131 ban->deleted = true;
6132 } else {
6133 bdrv_do_remove_aio_context_notifier(ban);
6134 }
6135 return;
6136 }
6137 }
6138
6139 abort();
6140}
6141
6142int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts,
6143 BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
6144 Error **errp)
6145{
6146 if (!bs->drv) {
6147 error_setg(errp, "Node is ejected");
6148 return -ENOMEDIUM;
6149 }
6150 if (!bs->drv->bdrv_amend_options) {
6151 error_setg(errp, "Block driver '%s' does not support option amendment",
6152 bs->drv->format_name);
6153 return -ENOTSUP;
6154 }
6155 return bs->drv->bdrv_amend_options(bs, opts, status_cb, cb_opaque, errp);
6156}
6157
6158/* This function will be called by the bdrv_recurse_is_first_non_filter method
6159 * of block filter and by bdrv_is_first_non_filter.
6160 * It is used to test if the given bs is the candidate or recurse more in the
6161 * node graph.
6162 */
6163bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
6164 BlockDriverState *candidate)
6165{
6166 /* return false if basic checks fails */
6167 if (!bs || !bs->drv) {
6168 return false;
6169 }
6170
6171 /* the code reached a non block filter driver -> check if the bs is
6172 * the same as the candidate. It's the recursion termination condition.
6173 */
6174 if (!bs->drv->is_filter) {
6175 return bs == candidate;
6176 }
6177 /* Down this path the driver is a block filter driver */
6178
6179 /* If the block filter recursion method is defined use it to recurse down
6180 * the node graph.
6181 */
6182 if (bs->drv->bdrv_recurse_is_first_non_filter) {
6183 return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate);
6184 }
6185
6186 /* the driver is a block filter but don't allow to recurse -> return false
6187 */
6188 return false;
6189}
6190
6191/* This function checks if the candidate is the first non filter bs down it's
6192 * bs chain. Since we don't have pointers to parents it explore all bs chains
6193 * from the top. Some filters can choose not to pass down the recursion.
6194 */
6195bool bdrv_is_first_non_filter(BlockDriverState *candidate)
6196{
6197 BlockDriverState *bs;
6198 BdrvNextIterator it;
6199
6200 /* walk down the bs forest recursively */
6201 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
6202 bool perm;
6203
6204 /* try to recurse in this top level bs */
6205 perm = bdrv_recurse_is_first_non_filter(bs, candidate);
6206
6207 /* candidate is the first non filter */
6208 if (perm) {
6209 bdrv_next_cleanup(&it);
6210 return true;
6211 }
6212 }
6213
6214 return false;
6215}
6216
6217BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
6218 const char *node_name, Error **errp)
6219{
6220 BlockDriverState *to_replace_bs = bdrv_find_node(node_name);
6221 AioContext *aio_context;
6222
6223 if (!to_replace_bs) {
6224 error_setg(errp, "Node name '%s' not found", node_name);
6225 return NULL;
6226 }
6227
6228 aio_context = bdrv_get_aio_context(to_replace_bs);
6229 aio_context_acquire(aio_context);
6230
6231 if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) {
6232 to_replace_bs = NULL;
6233 goto out;
6234 }
6235
6236 /* We don't want arbitrary node of the BDS chain to be replaced only the top
6237 * most non filter in order to prevent data corruption.
6238 * Another benefit is that this tests exclude backing files which are
6239 * blocked by the backing blockers.
6240 */
6241 if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) {
6242 error_setg(errp, "Only top most non filter can be replaced");
6243 to_replace_bs = NULL;
6244 goto out;
6245 }
6246
6247out:
6248 aio_context_release(aio_context);
6249 return to_replace_bs;
6250}
6251
6252/**
6253 * Iterates through the list of runtime option keys that are said to
6254 * be "strong" for a BDS. An option is called "strong" if it changes
6255 * a BDS's data. For example, the null block driver's "size" and
6256 * "read-zeroes" options are strong, but its "latency-ns" option is
6257 * not.
6258 *
6259 * If a key returned by this function ends with a dot, all options
6260 * starting with that prefix are strong.
6261 */
6262static const char *const *strong_options(BlockDriverState *bs,
6263 const char *const *curopt)
6264{
6265 static const char *const global_options[] = {
6266 "driver", "filename", NULL
6267 };
6268
6269 if (!curopt) {
6270 return &global_options[0];
6271 }
6272
6273 curopt++;
6274 if (curopt == &global_options[ARRAY_SIZE(global_options) - 1] && bs->drv) {
6275 curopt = bs->drv->strong_runtime_opts;
6276 }
6277
6278 return (curopt && *curopt) ? curopt : NULL;
6279}
6280
6281/**
6282 * Copies all strong runtime options from bs->options to the given
6283 * QDict. The set of strong option keys is determined by invoking
6284 * strong_options().
6285 *
6286 * Returns true iff any strong option was present in bs->options (and
6287 * thus copied to the target QDict) with the exception of "filename"
6288 * and "driver". The caller is expected to use this value to decide
6289 * whether the existence of strong options prevents the generation of
6290 * a plain filename.
6291 */
6292static bool append_strong_runtime_options(QDict *d, BlockDriverState *bs)
6293{
6294 bool found_any = false;
6295 const char *const *option_name = NULL;
6296
6297 if (!bs->drv) {
6298 return false;
6299 }
6300
6301 while ((option_name = strong_options(bs, option_name))) {
6302 bool option_given = false;
6303
6304 assert(strlen(*option_name) > 0);
6305 if ((*option_name)[strlen(*option_name) - 1] != '.') {
6306 QObject *entry = qdict_get(bs->options, *option_name);
6307 if (!entry) {
6308 continue;
6309 }
6310
6311 qdict_put_obj(d, *option_name, qobject_ref(entry));
6312 option_given = true;
6313 } else {
6314 const QDictEntry *entry;
6315 for (entry = qdict_first(bs->options); entry;
6316 entry = qdict_next(bs->options, entry))
6317 {
6318 if (strstart(qdict_entry_key(entry), *option_name, NULL)) {
6319 qdict_put_obj(d, qdict_entry_key(entry),
6320 qobject_ref(qdict_entry_value(entry)));
6321 option_given = true;
6322 }
6323 }
6324 }
6325
6326 /* While "driver" and "filename" need to be included in a JSON filename,
6327 * their existence does not prohibit generation of a plain filename. */
6328 if (!found_any && option_given &&
6329 strcmp(*option_name, "driver") && strcmp(*option_name, "filename"))
6330 {
6331 found_any = true;
6332 }
6333 }
6334
6335 if (!qdict_haskey(d, "driver")) {
6336 /* Drivers created with bdrv_new_open_driver() may not have a
6337 * @driver option. Add it here. */
6338 qdict_put_str(d, "driver", bs->drv->format_name);
6339 }
6340
6341 return found_any;
6342}
6343
6344/* Note: This function may return false positives; it may return true
6345 * even if opening the backing file specified by bs's image header
6346 * would result in exactly bs->backing. */
6347static bool bdrv_backing_overridden(BlockDriverState *bs)
6348{
6349 if (bs->backing) {
6350 return strcmp(bs->auto_backing_file,
6351 bs->backing->bs->filename);
6352 } else {
6353 /* No backing BDS, so if the image header reports any backing
6354 * file, it must have been suppressed */
6355 return bs->auto_backing_file[0] != '\0';
6356 }
6357}
6358
6359/* Updates the following BDS fields:
6360 * - exact_filename: A filename which may be used for opening a block device
6361 * which (mostly) equals the given BDS (even without any
6362 * other options; so reading and writing must return the same
6363 * results, but caching etc. may be different)
6364 * - full_open_options: Options which, when given when opening a block device
6365 * (without a filename), result in a BDS (mostly)
6366 * equalling the given one
6367 * - filename: If exact_filename is set, it is copied here. Otherwise,
6368 * full_open_options is converted to a JSON object, prefixed with
6369 * "json:" (for use through the JSON pseudo protocol) and put here.
6370 */
6371void bdrv_refresh_filename(BlockDriverState *bs)
6372{
6373 BlockDriver *drv = bs->drv;
6374 BdrvChild *child;
6375 QDict *opts;
6376 bool backing_overridden;
6377 bool generate_json_filename; /* Whether our default implementation should
6378 fill exact_filename (false) or not (true) */
6379
6380 if (!drv) {
6381 return;
6382 }
6383
6384 /* This BDS's file name may depend on any of its children's file names, so
6385 * refresh those first */
6386 QLIST_FOREACH(child, &bs->children, next) {
6387 bdrv_refresh_filename(child->bs);
6388 }
6389
6390 if (bs->implicit) {
6391 /* For implicit nodes, just copy everything from the single child */
6392 child = QLIST_FIRST(&bs->children);
6393 assert(QLIST_NEXT(child, next) == NULL);
6394
6395 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
6396 child->bs->exact_filename);
6397 pstrcpy(bs->filename, sizeof(bs->filename), child->bs->filename);
6398
6399 bs->full_open_options = qobject_ref(child->bs->full_open_options);
6400
6401 return;
6402 }
6403
6404 backing_overridden = bdrv_backing_overridden(bs);
6405
6406 if (bs->open_flags & BDRV_O_NO_IO) {
6407 /* Without I/O, the backing file does not change anything.
6408 * Therefore, in such a case (primarily qemu-img), we can
6409 * pretend the backing file has not been overridden even if
6410 * it technically has been. */
6411 backing_overridden = false;
6412 }
6413
6414 /* Gather the options QDict */
6415 opts = qdict_new();
6416 generate_json_filename = append_strong_runtime_options(opts, bs);
6417 generate_json_filename |= backing_overridden;
6418
6419 if (drv->bdrv_gather_child_options) {
6420 /* Some block drivers may not want to present all of their children's
6421 * options, or name them differently from BdrvChild.name */
6422 drv->bdrv_gather_child_options(bs, opts, backing_overridden);
6423 } else {
6424 QLIST_FOREACH(child, &bs->children, next) {
6425 if (child->role == &child_backing && !backing_overridden) {
6426 /* We can skip the backing BDS if it has not been overridden */
6427 continue;
6428 }
6429
6430 qdict_put(opts, child->name,
6431 qobject_ref(child->bs->full_open_options));
6432 }
6433
6434 if (backing_overridden && !bs->backing) {
6435 /* Force no backing file */
6436 qdict_put_null(opts, "backing");
6437 }
6438 }
6439
6440 qobject_unref(bs->full_open_options);
6441 bs->full_open_options = opts;
6442
6443 if (drv->bdrv_refresh_filename) {
6444 /* Obsolete information is of no use here, so drop the old file name
6445 * information before refreshing it */
6446 bs->exact_filename[0] = '\0';
6447
6448 drv->bdrv_refresh_filename(bs);
6449 } else if (bs->file) {
6450 /* Try to reconstruct valid information from the underlying file */
6451
6452 bs->exact_filename[0] = '\0';
6453
6454 /*
6455 * We can use the underlying file's filename if:
6456 * - it has a filename,
6457 * - the file is a protocol BDS, and
6458 * - opening that file (as this BDS's format) will automatically create
6459 * the BDS tree we have right now, that is:
6460 * - the user did not significantly change this BDS's behavior with
6461 * some explicit (strong) options
6462 * - no non-file child of this BDS has been overridden by the user
6463 * Both of these conditions are represented by generate_json_filename.
6464 */
6465 if (bs->file->bs->exact_filename[0] &&
6466 bs->file->bs->drv->bdrv_file_open &&
6467 !generate_json_filename)
6468 {
6469 strcpy(bs->exact_filename, bs->file->bs->exact_filename);
6470 }
6471 }
6472
6473 if (bs->exact_filename[0]) {
6474 pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename);
6475 } else {
6476 QString *json = qobject_to_json(QOBJECT(bs->full_open_options));
6477 snprintf(bs->filename, sizeof(bs->filename), "json:%s",
6478 qstring_get_str(json));
6479 qobject_unref(json);
6480 }
6481}
6482
6483char *bdrv_dirname(BlockDriverState *bs, Error **errp)
6484{
6485 BlockDriver *drv = bs->drv;
6486
6487 if (!drv) {
6488 error_setg(errp, "Node '%s' is ejected", bs->node_name);
6489 return NULL;
6490 }
6491
6492 if (drv->bdrv_dirname) {
6493 return drv->bdrv_dirname(bs, errp);
6494 }
6495
6496 if (bs->file) {
6497 return bdrv_dirname(bs->file->bs, errp);
6498 }
6499
6500 bdrv_refresh_filename(bs);
6501 if (bs->exact_filename[0] != '\0') {
6502 return path_combine(bs->exact_filename, "");
6503 }
6504
6505 error_setg(errp, "Cannot generate a base directory for %s nodes",
6506 drv->format_name);
6507 return NULL;
6508}
6509
6510/*
6511 * Hot add/remove a BDS's child. So the user can take a child offline when
6512 * it is broken and take a new child online
6513 */
6514void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs,
6515 Error **errp)
6516{
6517
6518 if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) {
6519 error_setg(errp, "The node %s does not support adding a child",
6520 bdrv_get_device_or_node_name(parent_bs));
6521 return;
6522 }
6523
6524 if (!QLIST_EMPTY(&child_bs->parents)) {
6525 error_setg(errp, "The node %s already has a parent",
6526 child_bs->node_name);
6527 return;
6528 }
6529
6530 parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp);
6531}
6532
6533void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp)
6534{
6535 BdrvChild *tmp;
6536
6537 if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) {
6538 error_setg(errp, "The node %s does not support removing a child",
6539 bdrv_get_device_or_node_name(parent_bs));
6540 return;
6541 }
6542
6543 QLIST_FOREACH(tmp, &parent_bs->children, next) {
6544 if (tmp == child) {
6545 break;
6546 }
6547 }
6548
6549 if (!tmp) {
6550 error_setg(errp, "The node %s does not have a child named %s",
6551 bdrv_get_device_or_node_name(parent_bs),
6552 bdrv_get_device_or_node_name(child->bs));
6553 return;
6554 }
6555
6556 parent_bs->drv->bdrv_del_child(parent_bs, child, errp);
6557}
6558
6559bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
6560 uint32_t granularity, Error **errp)
6561{
6562 BlockDriver *drv = bs->drv;
6563
6564 if (!drv) {
6565 error_setg_errno(errp, ENOMEDIUM,
6566 "Can't store persistent bitmaps to %s",
6567 bdrv_get_device_or_node_name(bs));
6568 return false;
6569 }
6570
6571 if (!drv->bdrv_can_store_new_dirty_bitmap) {
6572 error_setg_errno(errp, ENOTSUP,
6573 "Can't store persistent bitmaps to %s",
6574 bdrv_get_device_or_node_name(bs));
6575 return false;
6576 }
6577
6578 return drv->bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp);
6579}
6580