target/arm: Factor out 'generate singlestep exception' function
[qemu/ar7.git] / block.c
blobcbd8da5f3bd4e43f651de655b4151b8c4a890bef
1 /*
2 * QEMU System Emulator block driver
4 * Copyright (c) 2003 Fabrice Bellard
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:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
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.
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/module.h"
34 #include "qapi/error.h"
35 #include "qapi/qmp/qdict.h"
36 #include "qapi/qmp/qjson.h"
37 #include "qapi/qmp/qnull.h"
38 #include "qapi/qmp/qstring.h"
39 #include "qapi/qobject-output-visitor.h"
40 #include "qapi/qapi-visit-block-core.h"
41 #include "sysemu/block-backend.h"
42 #include "sysemu/sysemu.h"
43 #include "qemu/notify.h"
44 #include "qemu/option.h"
45 #include "qemu/coroutine.h"
46 #include "block/qapi.h"
47 #include "qemu/timer.h"
48 #include "qemu/cutils.h"
49 #include "qemu/id.h"
51 #ifdef CONFIG_BSD
52 #include <sys/ioctl.h>
53 #include <sys/queue.h>
54 #ifndef __DragonFly__
55 #include <sys/disk.h>
56 #endif
57 #endif
59 #ifdef _WIN32
60 #include <windows.h>
61 #endif
63 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
65 static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states =
66 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states);
68 static QTAILQ_HEAD(, BlockDriverState) all_bdrv_states =
69 QTAILQ_HEAD_INITIALIZER(all_bdrv_states);
71 static QLIST_HEAD(, BlockDriver) bdrv_drivers =
72 QLIST_HEAD_INITIALIZER(bdrv_drivers);
74 static BlockDriverState *bdrv_open_inherit(const char *filename,
75 const char *reference,
76 QDict *options, int flags,
77 BlockDriverState *parent,
78 const BdrvChildRole *child_role,
79 Error **errp);
81 /* If non-zero, use only whitelisted block drivers */
82 static int use_bdrv_whitelist;
84 #ifdef _WIN32
85 static int is_windows_drive_prefix(const char *filename)
87 return (((filename[0] >= 'a' && filename[0] <= 'z') ||
88 (filename[0] >= 'A' && filename[0] <= 'Z')) &&
89 filename[1] == ':');
92 int is_windows_drive(const char *filename)
94 if (is_windows_drive_prefix(filename) &&
95 filename[2] == '\0')
96 return 1;
97 if (strstart(filename, "\\\\.\\", NULL) ||
98 strstart(filename, "//./", NULL))
99 return 1;
100 return 0;
102 #endif
104 size_t bdrv_opt_mem_align(BlockDriverState *bs)
106 if (!bs || !bs->drv) {
107 /* page size or 4k (hdd sector size) should be on the safe side */
108 return MAX(4096, getpagesize());
111 return bs->bl.opt_mem_alignment;
114 size_t bdrv_min_mem_align(BlockDriverState *bs)
116 if (!bs || !bs->drv) {
117 /* page size or 4k (hdd sector size) should be on the safe side */
118 return MAX(4096, getpagesize());
121 return bs->bl.min_mem_alignment;
124 /* check if the path starts with "<protocol>:" */
125 int path_has_protocol(const char *path)
127 const char *p;
129 #ifdef _WIN32
130 if (is_windows_drive(path) ||
131 is_windows_drive_prefix(path)) {
132 return 0;
134 p = path + strcspn(path, ":/\\");
135 #else
136 p = path + strcspn(path, ":/");
137 #endif
139 return *p == ':';
142 int path_is_absolute(const char *path)
144 #ifdef _WIN32
145 /* specific case for names like: "\\.\d:" */
146 if (is_windows_drive(path) || is_windows_drive_prefix(path)) {
147 return 1;
149 return (*path == '/' || *path == '\\');
150 #else
151 return (*path == '/');
152 #endif
155 /* if filename is absolute, just return its duplicate. Otherwise, build a
156 path to it by considering it is relative to base_path. URL are
157 supported. */
158 char *path_combine(const char *base_path, const char *filename)
160 const char *protocol_stripped = NULL;
161 const char *p, *p1;
162 char *result;
163 int len;
165 if (path_is_absolute(filename)) {
166 return g_strdup(filename);
169 if (path_has_protocol(base_path)) {
170 protocol_stripped = strchr(base_path, ':');
171 if (protocol_stripped) {
172 protocol_stripped++;
175 p = protocol_stripped ?: base_path;
177 p1 = strrchr(base_path, '/');
178 #ifdef _WIN32
180 const char *p2;
181 p2 = strrchr(base_path, '\\');
182 if (!p1 || p2 > p1) {
183 p1 = p2;
186 #endif
187 if (p1) {
188 p1++;
189 } else {
190 p1 = base_path;
192 if (p1 > p) {
193 p = p1;
195 len = p - base_path;
197 result = g_malloc(len + strlen(filename) + 1);
198 memcpy(result, base_path, len);
199 strcpy(result + len, filename);
201 return result;
205 * Helper function for bdrv_parse_filename() implementations to remove optional
206 * protocol prefixes (especially "file:") from a filename and for putting the
207 * stripped filename into the options QDict if there is such a prefix.
209 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix,
210 QDict *options)
212 if (strstart(filename, prefix, &filename)) {
213 /* Stripping the explicit protocol prefix may result in a protocol
214 * prefix being (wrongly) detected (if the filename contains a colon) */
215 if (path_has_protocol(filename)) {
216 QString *fat_filename;
218 /* This means there is some colon before the first slash; therefore,
219 * this cannot be an absolute path */
220 assert(!path_is_absolute(filename));
222 /* And we can thus fix the protocol detection issue by prefixing it
223 * by "./" */
224 fat_filename = qstring_from_str("./");
225 qstring_append(fat_filename, filename);
227 assert(!path_has_protocol(qstring_get_str(fat_filename)));
229 qdict_put(options, "filename", fat_filename);
230 } else {
231 /* If no protocol prefix was detected, we can use the shortened
232 * filename as-is */
233 qdict_put_str(options, "filename", filename);
239 /* Returns whether the image file is opened as read-only. Note that this can
240 * return false and writing to the image file is still not possible because the
241 * image is inactivated. */
242 bool bdrv_is_read_only(BlockDriverState *bs)
244 return bs->read_only;
247 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
248 bool ignore_allow_rdw, Error **errp)
250 /* Do not set read_only if copy_on_read is enabled */
251 if (bs->copy_on_read && read_only) {
252 error_setg(errp, "Can't set node '%s' to r/o with copy-on-read enabled",
253 bdrv_get_device_or_node_name(bs));
254 return -EINVAL;
257 /* Do not clear read_only if it is prohibited */
258 if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR) &&
259 !ignore_allow_rdw)
261 error_setg(errp, "Node '%s' is read only",
262 bdrv_get_device_or_node_name(bs));
263 return -EPERM;
266 return 0;
270 * Called by a driver that can only provide a read-only image.
272 * Returns 0 if the node is already read-only or it could switch the node to
273 * read-only because BDRV_O_AUTO_RDONLY is set.
275 * Returns -EACCES if the node is read-write and BDRV_O_AUTO_RDONLY is not set
276 * or bdrv_can_set_read_only() forbids making the node read-only. If @errmsg
277 * is not NULL, it is used as the error message for the Error object.
279 int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
280 Error **errp)
282 int ret = 0;
284 if (!(bs->open_flags & BDRV_O_RDWR)) {
285 return 0;
287 if (!(bs->open_flags & BDRV_O_AUTO_RDONLY)) {
288 goto fail;
291 ret = bdrv_can_set_read_only(bs, true, false, NULL);
292 if (ret < 0) {
293 goto fail;
296 bs->read_only = true;
297 bs->open_flags &= ~BDRV_O_RDWR;
299 return 0;
301 fail:
302 error_setg(errp, "%s", errmsg ?: "Image is read-only");
303 return -EACCES;
307 * If @backing is empty, this function returns NULL without setting
308 * @errp. In all other cases, NULL will only be returned with @errp
309 * set.
311 * Therefore, a return value of NULL without @errp set means that
312 * there is no backing file; if @errp is set, there is one but its
313 * absolute filename cannot be generated.
315 char *bdrv_get_full_backing_filename_from_filename(const char *backed,
316 const char *backing,
317 Error **errp)
319 if (backing[0] == '\0') {
320 return NULL;
321 } else if (path_has_protocol(backing) || path_is_absolute(backing)) {
322 return g_strdup(backing);
323 } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) {
324 error_setg(errp, "Cannot use relative backing file names for '%s'",
325 backed);
326 return NULL;
327 } else {
328 return path_combine(backed, backing);
333 * If @filename is empty or NULL, this function returns NULL without
334 * setting @errp. In all other cases, NULL will only be returned with
335 * @errp set.
337 static char *bdrv_make_absolute_filename(BlockDriverState *relative_to,
338 const char *filename, Error **errp)
340 char *dir, *full_name;
342 if (!filename || filename[0] == '\0') {
343 return NULL;
344 } else if (path_has_protocol(filename) || path_is_absolute(filename)) {
345 return g_strdup(filename);
348 dir = bdrv_dirname(relative_to, errp);
349 if (!dir) {
350 return NULL;
353 full_name = g_strconcat(dir, filename, NULL);
354 g_free(dir);
355 return full_name;
358 char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp)
360 return bdrv_make_absolute_filename(bs, bs->backing_file, errp);
363 void bdrv_register(BlockDriver *bdrv)
365 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list);
368 BlockDriverState *bdrv_new(void)
370 BlockDriverState *bs;
371 int i;
373 bs = g_new0(BlockDriverState, 1);
374 QLIST_INIT(&bs->dirty_bitmaps);
375 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
376 QLIST_INIT(&bs->op_blockers[i]);
378 notifier_with_return_list_init(&bs->before_write_notifiers);
379 qemu_co_mutex_init(&bs->reqs_lock);
380 qemu_mutex_init(&bs->dirty_bitmap_mutex);
381 bs->refcnt = 1;
382 bs->aio_context = qemu_get_aio_context();
384 qemu_co_queue_init(&bs->flush_queue);
386 for (i = 0; i < bdrv_drain_all_count; i++) {
387 bdrv_drained_begin(bs);
390 QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list);
392 return bs;
395 static BlockDriver *bdrv_do_find_format(const char *format_name)
397 BlockDriver *drv1;
399 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
400 if (!strcmp(drv1->format_name, format_name)) {
401 return drv1;
405 return NULL;
408 BlockDriver *bdrv_find_format(const char *format_name)
410 BlockDriver *drv1;
411 int i;
413 drv1 = bdrv_do_find_format(format_name);
414 if (drv1) {
415 return drv1;
418 /* The driver isn't registered, maybe we need to load a module */
419 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
420 if (!strcmp(block_driver_modules[i].format_name, format_name)) {
421 block_module_load_one(block_driver_modules[i].library_name);
422 break;
426 return bdrv_do_find_format(format_name);
429 static int bdrv_format_is_whitelisted(const char *format_name, bool read_only)
431 static const char *whitelist_rw[] = {
432 CONFIG_BDRV_RW_WHITELIST
434 static const char *whitelist_ro[] = {
435 CONFIG_BDRV_RO_WHITELIST
437 const char **p;
439 if (!whitelist_rw[0] && !whitelist_ro[0]) {
440 return 1; /* no whitelist, anything goes */
443 for (p = whitelist_rw; *p; p++) {
444 if (!strcmp(format_name, *p)) {
445 return 1;
448 if (read_only) {
449 for (p = whitelist_ro; *p; p++) {
450 if (!strcmp(format_name, *p)) {
451 return 1;
455 return 0;
458 int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
460 return bdrv_format_is_whitelisted(drv->format_name, read_only);
463 bool bdrv_uses_whitelist(void)
465 return use_bdrv_whitelist;
468 typedef struct CreateCo {
469 BlockDriver *drv;
470 char *filename;
471 QemuOpts *opts;
472 int ret;
473 Error *err;
474 } CreateCo;
476 static void coroutine_fn bdrv_create_co_entry(void *opaque)
478 Error *local_err = NULL;
479 int ret;
481 CreateCo *cco = opaque;
482 assert(cco->drv);
484 ret = cco->drv->bdrv_co_create_opts(cco->filename, cco->opts, &local_err);
485 error_propagate(&cco->err, local_err);
486 cco->ret = ret;
489 int bdrv_create(BlockDriver *drv, const char* filename,
490 QemuOpts *opts, Error **errp)
492 int ret;
494 Coroutine *co;
495 CreateCo cco = {
496 .drv = drv,
497 .filename = g_strdup(filename),
498 .opts = opts,
499 .ret = NOT_DONE,
500 .err = NULL,
503 if (!drv->bdrv_co_create_opts) {
504 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name);
505 ret = -ENOTSUP;
506 goto out;
509 if (qemu_in_coroutine()) {
510 /* Fast-path if already in coroutine context */
511 bdrv_create_co_entry(&cco);
512 } else {
513 co = qemu_coroutine_create(bdrv_create_co_entry, &cco);
514 qemu_coroutine_enter(co);
515 while (cco.ret == NOT_DONE) {
516 aio_poll(qemu_get_aio_context(), true);
520 ret = cco.ret;
521 if (ret < 0) {
522 if (cco.err) {
523 error_propagate(errp, cco.err);
524 } else {
525 error_setg_errno(errp, -ret, "Could not create image");
529 out:
530 g_free(cco.filename);
531 return ret;
534 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
536 BlockDriver *drv;
537 Error *local_err = NULL;
538 int ret;
540 drv = bdrv_find_protocol(filename, true, errp);
541 if (drv == NULL) {
542 return -ENOENT;
545 ret = bdrv_create(drv, filename, opts, &local_err);
546 error_propagate(errp, local_err);
547 return ret;
551 * Try to get @bs's logical and physical block size.
552 * On success, store them in @bsz struct and return 0.
553 * On failure return -errno.
554 * @bs must not be empty.
556 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
558 BlockDriver *drv = bs->drv;
560 if (drv && drv->bdrv_probe_blocksizes) {
561 return drv->bdrv_probe_blocksizes(bs, bsz);
562 } else if (drv && drv->is_filter && bs->file) {
563 return bdrv_probe_blocksizes(bs->file->bs, bsz);
566 return -ENOTSUP;
570 * Try to get @bs's geometry (cyls, heads, sectors).
571 * On success, store them in @geo struct and return 0.
572 * On failure return -errno.
573 * @bs must not be empty.
575 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
577 BlockDriver *drv = bs->drv;
579 if (drv && drv->bdrv_probe_geometry) {
580 return drv->bdrv_probe_geometry(bs, geo);
581 } else if (drv && drv->is_filter && bs->file) {
582 return bdrv_probe_geometry(bs->file->bs, geo);
585 return -ENOTSUP;
589 * Create a uniquely-named empty temporary file.
590 * Return 0 upon success, otherwise a negative errno value.
592 int get_tmp_filename(char *filename, int size)
594 #ifdef _WIN32
595 char temp_dir[MAX_PATH];
596 /* GetTempFileName requires that its output buffer (4th param)
597 have length MAX_PATH or greater. */
598 assert(size >= MAX_PATH);
599 return (GetTempPath(MAX_PATH, temp_dir)
600 && GetTempFileName(temp_dir, "qem", 0, filename)
601 ? 0 : -GetLastError());
602 #else
603 int fd;
604 const char *tmpdir;
605 tmpdir = getenv("TMPDIR");
606 if (!tmpdir) {
607 tmpdir = "/var/tmp";
609 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) {
610 return -EOVERFLOW;
612 fd = mkstemp(filename);
613 if (fd < 0) {
614 return -errno;
616 if (close(fd) != 0) {
617 unlink(filename);
618 return -errno;
620 return 0;
621 #endif
625 * Detect host devices. By convention, /dev/cdrom[N] is always
626 * recognized as a host CDROM.
628 static BlockDriver *find_hdev_driver(const char *filename)
630 int score_max = 0, score;
631 BlockDriver *drv = NULL, *d;
633 QLIST_FOREACH(d, &bdrv_drivers, list) {
634 if (d->bdrv_probe_device) {
635 score = d->bdrv_probe_device(filename);
636 if (score > score_max) {
637 score_max = score;
638 drv = d;
643 return drv;
646 static BlockDriver *bdrv_do_find_protocol(const char *protocol)
648 BlockDriver *drv1;
650 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
651 if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) {
652 return drv1;
656 return NULL;
659 BlockDriver *bdrv_find_protocol(const char *filename,
660 bool allow_protocol_prefix,
661 Error **errp)
663 BlockDriver *drv1;
664 char protocol[128];
665 int len;
666 const char *p;
667 int i;
669 /* TODO Drivers without bdrv_file_open must be specified explicitly */
672 * XXX(hch): we really should not let host device detection
673 * override an explicit protocol specification, but moving this
674 * later breaks access to device names with colons in them.
675 * Thanks to the brain-dead persistent naming schemes on udev-
676 * based Linux systems those actually are quite common.
678 drv1 = find_hdev_driver(filename);
679 if (drv1) {
680 return drv1;
683 if (!path_has_protocol(filename) || !allow_protocol_prefix) {
684 return &bdrv_file;
687 p = strchr(filename, ':');
688 assert(p != NULL);
689 len = p - filename;
690 if (len > sizeof(protocol) - 1)
691 len = sizeof(protocol) - 1;
692 memcpy(protocol, filename, len);
693 protocol[len] = '\0';
695 drv1 = bdrv_do_find_protocol(protocol);
696 if (drv1) {
697 return drv1;
700 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
701 if (block_driver_modules[i].protocol_name &&
702 !strcmp(block_driver_modules[i].protocol_name, protocol)) {
703 block_module_load_one(block_driver_modules[i].library_name);
704 break;
708 drv1 = bdrv_do_find_protocol(protocol);
709 if (!drv1) {
710 error_setg(errp, "Unknown protocol '%s'", protocol);
712 return drv1;
716 * Guess image format by probing its contents.
717 * This is not a good idea when your image is raw (CVE-2008-2004), but
718 * we do it anyway for backward compatibility.
720 * @buf contains the image's first @buf_size bytes.
721 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
722 * but can be smaller if the image file is smaller)
723 * @filename is its filename.
725 * For all block drivers, call the bdrv_probe() method to get its
726 * probing score.
727 * Return the first block driver with the highest probing score.
729 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
730 const char *filename)
732 int score_max = 0, score;
733 BlockDriver *drv = NULL, *d;
735 QLIST_FOREACH(d, &bdrv_drivers, list) {
736 if (d->bdrv_probe) {
737 score = d->bdrv_probe(buf, buf_size, filename);
738 if (score > score_max) {
739 score_max = score;
740 drv = d;
745 return drv;
748 static int find_image_format(BlockBackend *file, const char *filename,
749 BlockDriver **pdrv, Error **errp)
751 BlockDriver *drv;
752 uint8_t buf[BLOCK_PROBE_BUF_SIZE];
753 int ret = 0;
755 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
756 if (blk_is_sg(file) || !blk_is_inserted(file) || blk_getlength(file) == 0) {
757 *pdrv = &bdrv_raw;
758 return ret;
761 ret = blk_pread(file, 0, buf, sizeof(buf));
762 if (ret < 0) {
763 error_setg_errno(errp, -ret, "Could not read image for determining its "
764 "format");
765 *pdrv = NULL;
766 return ret;
769 drv = bdrv_probe_all(buf, ret, filename);
770 if (!drv) {
771 error_setg(errp, "Could not determine image format: No compatible "
772 "driver found");
773 ret = -ENOENT;
775 *pdrv = drv;
776 return ret;
780 * Set the current 'total_sectors' value
781 * Return 0 on success, -errno on error.
783 int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
785 BlockDriver *drv = bs->drv;
787 if (!drv) {
788 return -ENOMEDIUM;
791 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
792 if (bdrv_is_sg(bs))
793 return 0;
795 /* query actual device if possible, otherwise just trust the hint */
796 if (drv->bdrv_getlength) {
797 int64_t length = drv->bdrv_getlength(bs);
798 if (length < 0) {
799 return length;
801 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE);
804 bs->total_sectors = hint;
805 return 0;
809 * Combines a QDict of new block driver @options with any missing options taken
810 * from @old_options, so that leaving out an option defaults to its old value.
812 static void bdrv_join_options(BlockDriverState *bs, QDict *options,
813 QDict *old_options)
815 if (bs->drv && bs->drv->bdrv_join_options) {
816 bs->drv->bdrv_join_options(options, old_options);
817 } else {
818 qdict_join(options, old_options, false);
822 static BlockdevDetectZeroesOptions bdrv_parse_detect_zeroes(QemuOpts *opts,
823 int open_flags,
824 Error **errp)
826 Error *local_err = NULL;
827 char *value = qemu_opt_get_del(opts, "detect-zeroes");
828 BlockdevDetectZeroesOptions detect_zeroes =
829 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup, value,
830 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF, &local_err);
831 g_free(value);
832 if (local_err) {
833 error_propagate(errp, local_err);
834 return detect_zeroes;
837 if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
838 !(open_flags & BDRV_O_UNMAP))
840 error_setg(errp, "setting detect-zeroes to unmap is not allowed "
841 "without setting discard operation to unmap");
844 return detect_zeroes;
848 * Set open flags for a given discard mode
850 * Return 0 on success, -1 if the discard mode was invalid.
852 int bdrv_parse_discard_flags(const char *mode, int *flags)
854 *flags &= ~BDRV_O_UNMAP;
856 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) {
857 /* do nothing */
858 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) {
859 *flags |= BDRV_O_UNMAP;
860 } else {
861 return -1;
864 return 0;
868 * Set open flags for a given cache mode
870 * Return 0 on success, -1 if the cache mode was invalid.
872 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough)
874 *flags &= ~BDRV_O_CACHE_MASK;
876 if (!strcmp(mode, "off") || !strcmp(mode, "none")) {
877 *writethrough = false;
878 *flags |= BDRV_O_NOCACHE;
879 } else if (!strcmp(mode, "directsync")) {
880 *writethrough = true;
881 *flags |= BDRV_O_NOCACHE;
882 } else if (!strcmp(mode, "writeback")) {
883 *writethrough = false;
884 } else if (!strcmp(mode, "unsafe")) {
885 *writethrough = false;
886 *flags |= BDRV_O_NO_FLUSH;
887 } else if (!strcmp(mode, "writethrough")) {
888 *writethrough = true;
889 } else {
890 return -1;
893 return 0;
896 static char *bdrv_child_get_parent_desc(BdrvChild *c)
898 BlockDriverState *parent = c->opaque;
899 return g_strdup(bdrv_get_device_or_node_name(parent));
902 static void bdrv_child_cb_drained_begin(BdrvChild *child)
904 BlockDriverState *bs = child->opaque;
905 bdrv_do_drained_begin_quiesce(bs, NULL, false);
908 static bool bdrv_child_cb_drained_poll(BdrvChild *child)
910 BlockDriverState *bs = child->opaque;
911 return bdrv_drain_poll(bs, false, NULL, false);
914 static void bdrv_child_cb_drained_end(BdrvChild *child,
915 int *drained_end_counter)
917 BlockDriverState *bs = child->opaque;
918 bdrv_drained_end_no_poll(bs, drained_end_counter);
921 static void bdrv_child_cb_attach(BdrvChild *child)
923 BlockDriverState *bs = child->opaque;
924 bdrv_apply_subtree_drain(child, bs);
927 static void bdrv_child_cb_detach(BdrvChild *child)
929 BlockDriverState *bs = child->opaque;
930 bdrv_unapply_subtree_drain(child, bs);
933 static int bdrv_child_cb_inactivate(BdrvChild *child)
935 BlockDriverState *bs = child->opaque;
936 assert(bs->open_flags & BDRV_O_INACTIVE);
937 return 0;
940 static bool bdrv_child_cb_can_set_aio_ctx(BdrvChild *child, AioContext *ctx,
941 GSList **ignore, Error **errp)
943 BlockDriverState *bs = child->opaque;
944 return bdrv_can_set_aio_context(bs, ctx, ignore, errp);
947 static void bdrv_child_cb_set_aio_ctx(BdrvChild *child, AioContext *ctx,
948 GSList **ignore)
950 BlockDriverState *bs = child->opaque;
951 return bdrv_set_aio_context_ignore(bs, ctx, ignore);
955 * Returns the options and flags that a temporary snapshot should get, based on
956 * the originally requested flags (the originally requested image will have
957 * flags like a backing file)
959 static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
960 int parent_flags, QDict *parent_options)
962 *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY;
964 /* For temporary files, unconditional cache=unsafe is fine */
965 qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off");
966 qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
968 /* Copy the read-only and discard options from the parent */
969 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
970 qdict_copy_default(child_options, parent_options, BDRV_OPT_DISCARD);
972 /* aio=native doesn't work for cache.direct=off, so disable it for the
973 * temporary snapshot */
974 *child_flags &= ~BDRV_O_NATIVE_AIO;
978 * Returns the options and flags that bs->file should get if a protocol driver
979 * is expected, based on the given options and flags for the parent BDS
981 static void bdrv_inherited_options(int *child_flags, QDict *child_options,
982 int parent_flags, QDict *parent_options)
984 int flags = parent_flags;
986 /* Enable protocol handling, disable format probing for bs->file */
987 flags |= BDRV_O_PROTOCOL;
989 /* If the cache mode isn't explicitly set, inherit direct and no-flush from
990 * the parent. */
991 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
992 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
993 qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
995 /* Inherit the read-only option from the parent if it's not set */
996 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
997 qdict_copy_default(child_options, parent_options, BDRV_OPT_AUTO_READ_ONLY);
999 /* Our block drivers take care to send flushes and respect unmap policy,
1000 * so we can default to enable both on lower layers regardless of the
1001 * corresponding parent options. */
1002 qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap");
1004 /* Clear flags that only apply to the top layer */
1005 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ |
1006 BDRV_O_NO_IO);
1008 *child_flags = flags;
1011 const BdrvChildRole child_file = {
1012 .parent_is_bds = true,
1013 .get_parent_desc = bdrv_child_get_parent_desc,
1014 .inherit_options = bdrv_inherited_options,
1015 .drained_begin = bdrv_child_cb_drained_begin,
1016 .drained_poll = bdrv_child_cb_drained_poll,
1017 .drained_end = bdrv_child_cb_drained_end,
1018 .attach = bdrv_child_cb_attach,
1019 .detach = bdrv_child_cb_detach,
1020 .inactivate = bdrv_child_cb_inactivate,
1021 .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx,
1022 .set_aio_ctx = bdrv_child_cb_set_aio_ctx,
1026 * Returns the options and flags that bs->file should get if the use of formats
1027 * (and not only protocols) is permitted for it, based on the given options and
1028 * flags for the parent BDS
1030 static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options,
1031 int parent_flags, QDict *parent_options)
1033 child_file.inherit_options(child_flags, child_options,
1034 parent_flags, parent_options);
1036 *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO);
1039 const BdrvChildRole child_format = {
1040 .parent_is_bds = true,
1041 .get_parent_desc = bdrv_child_get_parent_desc,
1042 .inherit_options = bdrv_inherited_fmt_options,
1043 .drained_begin = bdrv_child_cb_drained_begin,
1044 .drained_poll = bdrv_child_cb_drained_poll,
1045 .drained_end = bdrv_child_cb_drained_end,
1046 .attach = bdrv_child_cb_attach,
1047 .detach = bdrv_child_cb_detach,
1048 .inactivate = bdrv_child_cb_inactivate,
1049 .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx,
1050 .set_aio_ctx = bdrv_child_cb_set_aio_ctx,
1053 static void bdrv_backing_attach(BdrvChild *c)
1055 BlockDriverState *parent = c->opaque;
1056 BlockDriverState *backing_hd = c->bs;
1058 assert(!parent->backing_blocker);
1059 error_setg(&parent->backing_blocker,
1060 "node is used as backing hd of '%s'",
1061 bdrv_get_device_or_node_name(parent));
1063 bdrv_refresh_filename(backing_hd);
1065 parent->open_flags &= ~BDRV_O_NO_BACKING;
1066 pstrcpy(parent->backing_file, sizeof(parent->backing_file),
1067 backing_hd->filename);
1068 pstrcpy(parent->backing_format, sizeof(parent->backing_format),
1069 backing_hd->drv ? backing_hd->drv->format_name : "");
1071 bdrv_op_block_all(backing_hd, parent->backing_blocker);
1072 /* Otherwise we won't be able to commit or stream */
1073 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,
1074 parent->backing_blocker);
1075 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_STREAM,
1076 parent->backing_blocker);
1078 * We do backup in 3 ways:
1079 * 1. drive backup
1080 * The target bs is new opened, and the source is top BDS
1081 * 2. blockdev backup
1082 * Both the source and the target are top BDSes.
1083 * 3. internal backup(used for block replication)
1084 * Both the source and the target are backing file
1086 * In case 1 and 2, neither the source nor the target is the backing file.
1087 * In case 3, we will block the top BDS, so there is only one block job
1088 * for the top BDS and its backing chain.
1090 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_SOURCE,
1091 parent->backing_blocker);
1092 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_TARGET,
1093 parent->backing_blocker);
1095 bdrv_child_cb_attach(c);
1098 static void bdrv_backing_detach(BdrvChild *c)
1100 BlockDriverState *parent = c->opaque;
1102 assert(parent->backing_blocker);
1103 bdrv_op_unblock_all(c->bs, parent->backing_blocker);
1104 error_free(parent->backing_blocker);
1105 parent->backing_blocker = NULL;
1107 bdrv_child_cb_detach(c);
1111 * Returns the options and flags that bs->backing should get, based on the
1112 * given options and flags for the parent BDS
1114 static void bdrv_backing_options(int *child_flags, QDict *child_options,
1115 int parent_flags, QDict *parent_options)
1117 int flags = parent_flags;
1119 /* The cache mode is inherited unmodified for backing files; except WCE,
1120 * which is only applied on the top level (BlockBackend) */
1121 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
1122 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
1123 qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
1125 /* backing files always opened read-only */
1126 qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on");
1127 qdict_set_default_str(child_options, BDRV_OPT_AUTO_READ_ONLY, "off");
1128 flags &= ~BDRV_O_COPY_ON_READ;
1130 /* snapshot=on is handled on the top layer */
1131 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY);
1133 *child_flags = flags;
1136 static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
1137 const char *filename, Error **errp)
1139 BlockDriverState *parent = c->opaque;
1140 bool read_only = bdrv_is_read_only(parent);
1141 int ret;
1143 if (read_only) {
1144 ret = bdrv_reopen_set_read_only(parent, false, errp);
1145 if (ret < 0) {
1146 return ret;
1150 ret = bdrv_change_backing_file(parent, filename,
1151 base->drv ? base->drv->format_name : "");
1152 if (ret < 0) {
1153 error_setg_errno(errp, -ret, "Could not update backing file link");
1156 if (read_only) {
1157 bdrv_reopen_set_read_only(parent, true, NULL);
1160 return ret;
1163 const BdrvChildRole child_backing = {
1164 .parent_is_bds = true,
1165 .get_parent_desc = bdrv_child_get_parent_desc,
1166 .attach = bdrv_backing_attach,
1167 .detach = bdrv_backing_detach,
1168 .inherit_options = bdrv_backing_options,
1169 .drained_begin = bdrv_child_cb_drained_begin,
1170 .drained_poll = bdrv_child_cb_drained_poll,
1171 .drained_end = bdrv_child_cb_drained_end,
1172 .inactivate = bdrv_child_cb_inactivate,
1173 .update_filename = bdrv_backing_update_filename,
1174 .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx,
1175 .set_aio_ctx = bdrv_child_cb_set_aio_ctx,
1178 static int bdrv_open_flags(BlockDriverState *bs, int flags)
1180 int open_flags = flags;
1183 * Clear flags that are internal to the block layer before opening the
1184 * image.
1186 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL);
1188 return open_flags;
1191 static void update_flags_from_options(int *flags, QemuOpts *opts)
1193 *flags &= ~(BDRV_O_CACHE_MASK | BDRV_O_RDWR | BDRV_O_AUTO_RDONLY);
1195 if (qemu_opt_get_bool_del(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
1196 *flags |= BDRV_O_NO_FLUSH;
1199 if (qemu_opt_get_bool_del(opts, BDRV_OPT_CACHE_DIRECT, false)) {
1200 *flags |= BDRV_O_NOCACHE;
1203 if (!qemu_opt_get_bool_del(opts, BDRV_OPT_READ_ONLY, false)) {
1204 *flags |= BDRV_O_RDWR;
1207 if (qemu_opt_get_bool_del(opts, BDRV_OPT_AUTO_READ_ONLY, false)) {
1208 *flags |= BDRV_O_AUTO_RDONLY;
1212 static void update_options_from_flags(QDict *options, int flags)
1214 if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) {
1215 qdict_put_bool(options, BDRV_OPT_CACHE_DIRECT, flags & BDRV_O_NOCACHE);
1217 if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) {
1218 qdict_put_bool(options, BDRV_OPT_CACHE_NO_FLUSH,
1219 flags & BDRV_O_NO_FLUSH);
1221 if (!qdict_haskey(options, BDRV_OPT_READ_ONLY)) {
1222 qdict_put_bool(options, BDRV_OPT_READ_ONLY, !(flags & BDRV_O_RDWR));
1224 if (!qdict_haskey(options, BDRV_OPT_AUTO_READ_ONLY)) {
1225 qdict_put_bool(options, BDRV_OPT_AUTO_READ_ONLY,
1226 flags & BDRV_O_AUTO_RDONLY);
1230 static void bdrv_assign_node_name(BlockDriverState *bs,
1231 const char *node_name,
1232 Error **errp)
1234 char *gen_node_name = NULL;
1236 if (!node_name) {
1237 node_name = gen_node_name = id_generate(ID_BLOCK);
1238 } else if (!id_wellformed(node_name)) {
1240 * Check for empty string or invalid characters, but not if it is
1241 * generated (generated names use characters not available to the user)
1243 error_setg(errp, "Invalid node name");
1244 return;
1247 /* takes care of avoiding namespaces collisions */
1248 if (blk_by_name(node_name)) {
1249 error_setg(errp, "node-name=%s is conflicting with a device id",
1250 node_name);
1251 goto out;
1254 /* takes care of avoiding duplicates node names */
1255 if (bdrv_find_node(node_name)) {
1256 error_setg(errp, "Duplicate node name");
1257 goto out;
1260 /* Make sure that the node name isn't truncated */
1261 if (strlen(node_name) >= sizeof(bs->node_name)) {
1262 error_setg(errp, "Node name too long");
1263 goto out;
1266 /* copy node name into the bs and insert it into the graph list */
1267 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
1268 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
1269 out:
1270 g_free(gen_node_name);
1273 static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv,
1274 const char *node_name, QDict *options,
1275 int open_flags, Error **errp)
1277 Error *local_err = NULL;
1278 int i, ret;
1280 bdrv_assign_node_name(bs, node_name, &local_err);
1281 if (local_err) {
1282 error_propagate(errp, local_err);
1283 return -EINVAL;
1286 bs->drv = drv;
1287 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
1288 bs->opaque = g_malloc0(drv->instance_size);
1290 if (drv->bdrv_file_open) {
1291 assert(!drv->bdrv_needs_filename || bs->filename[0]);
1292 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err);
1293 } else if (drv->bdrv_open) {
1294 ret = drv->bdrv_open(bs, options, open_flags, &local_err);
1295 } else {
1296 ret = 0;
1299 if (ret < 0) {
1300 if (local_err) {
1301 error_propagate(errp, local_err);
1302 } else if (bs->filename[0]) {
1303 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename);
1304 } else {
1305 error_setg_errno(errp, -ret, "Could not open image");
1307 goto open_failed;
1310 ret = refresh_total_sectors(bs, bs->total_sectors);
1311 if (ret < 0) {
1312 error_setg_errno(errp, -ret, "Could not refresh total sector count");
1313 return ret;
1316 bdrv_refresh_limits(bs, &local_err);
1317 if (local_err) {
1318 error_propagate(errp, local_err);
1319 return -EINVAL;
1322 assert(bdrv_opt_mem_align(bs) != 0);
1323 assert(bdrv_min_mem_align(bs) != 0);
1324 assert(is_power_of_2(bs->bl.request_alignment));
1326 for (i = 0; i < bs->quiesce_counter; i++) {
1327 if (drv->bdrv_co_drain_begin) {
1328 drv->bdrv_co_drain_begin(bs);
1332 return 0;
1333 open_failed:
1334 bs->drv = NULL;
1335 if (bs->file != NULL) {
1336 bdrv_unref_child(bs, bs->file);
1337 bs->file = NULL;
1339 g_free(bs->opaque);
1340 bs->opaque = NULL;
1341 return ret;
1344 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
1345 int flags, Error **errp)
1347 BlockDriverState *bs;
1348 int ret;
1350 bs = bdrv_new();
1351 bs->open_flags = flags;
1352 bs->explicit_options = qdict_new();
1353 bs->options = qdict_new();
1354 bs->opaque = NULL;
1356 update_options_from_flags(bs->options, flags);
1358 ret = bdrv_open_driver(bs, drv, node_name, bs->options, flags, errp);
1359 if (ret < 0) {
1360 qobject_unref(bs->explicit_options);
1361 bs->explicit_options = NULL;
1362 qobject_unref(bs->options);
1363 bs->options = NULL;
1364 bdrv_unref(bs);
1365 return NULL;
1368 return bs;
1371 QemuOptsList bdrv_runtime_opts = {
1372 .name = "bdrv_common",
1373 .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head),
1374 .desc = {
1376 .name = "node-name",
1377 .type = QEMU_OPT_STRING,
1378 .help = "Node name of the block device node",
1381 .name = "driver",
1382 .type = QEMU_OPT_STRING,
1383 .help = "Block driver to use for the node",
1386 .name = BDRV_OPT_CACHE_DIRECT,
1387 .type = QEMU_OPT_BOOL,
1388 .help = "Bypass software writeback cache on the host",
1391 .name = BDRV_OPT_CACHE_NO_FLUSH,
1392 .type = QEMU_OPT_BOOL,
1393 .help = "Ignore flush requests",
1396 .name = BDRV_OPT_READ_ONLY,
1397 .type = QEMU_OPT_BOOL,
1398 .help = "Node is opened in read-only mode",
1401 .name = BDRV_OPT_AUTO_READ_ONLY,
1402 .type = QEMU_OPT_BOOL,
1403 .help = "Node can become read-only if opening read-write fails",
1406 .name = "detect-zeroes",
1407 .type = QEMU_OPT_STRING,
1408 .help = "try to optimize zero writes (off, on, unmap)",
1411 .name = BDRV_OPT_DISCARD,
1412 .type = QEMU_OPT_STRING,
1413 .help = "discard operation (ignore/off, unmap/on)",
1416 .name = BDRV_OPT_FORCE_SHARE,
1417 .type = QEMU_OPT_BOOL,
1418 .help = "always accept other writers (default: off)",
1420 { /* end of list */ }
1425 * Common part for opening disk images and files
1427 * Removes all processed options from *options.
1429 static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file,
1430 QDict *options, Error **errp)
1432 int ret, open_flags;
1433 const char *filename;
1434 const char *driver_name = NULL;
1435 const char *node_name = NULL;
1436 const char *discard;
1437 QemuOpts *opts;
1438 BlockDriver *drv;
1439 Error *local_err = NULL;
1441 assert(bs->file == NULL);
1442 assert(options != NULL && bs->options != options);
1444 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
1445 qemu_opts_absorb_qdict(opts, options, &local_err);
1446 if (local_err) {
1447 error_propagate(errp, local_err);
1448 ret = -EINVAL;
1449 goto fail_opts;
1452 update_flags_from_options(&bs->open_flags, opts);
1454 driver_name = qemu_opt_get(opts, "driver");
1455 drv = bdrv_find_format(driver_name);
1456 assert(drv != NULL);
1458 bs->force_share = qemu_opt_get_bool(opts, BDRV_OPT_FORCE_SHARE, false);
1460 if (bs->force_share && (bs->open_flags & BDRV_O_RDWR)) {
1461 error_setg(errp,
1462 BDRV_OPT_FORCE_SHARE
1463 "=on can only be used with read-only images");
1464 ret = -EINVAL;
1465 goto fail_opts;
1468 if (file != NULL) {
1469 bdrv_refresh_filename(blk_bs(file));
1470 filename = blk_bs(file)->filename;
1471 } else {
1473 * Caution: while qdict_get_try_str() is fine, getting
1474 * non-string types would require more care. When @options
1475 * come from -blockdev or blockdev_add, its members are typed
1476 * according to the QAPI schema, but when they come from
1477 * -drive, they're all QString.
1479 filename = qdict_get_try_str(options, "filename");
1482 if (drv->bdrv_needs_filename && (!filename || !filename[0])) {
1483 error_setg(errp, "The '%s' block driver requires a file name",
1484 drv->format_name);
1485 ret = -EINVAL;
1486 goto fail_opts;
1489 trace_bdrv_open_common(bs, filename ?: "", bs->open_flags,
1490 drv->format_name);
1492 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
1494 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
1495 if (!bs->read_only && bdrv_is_whitelisted(drv, true)) {
1496 ret = bdrv_apply_auto_read_only(bs, NULL, NULL);
1497 } else {
1498 ret = -ENOTSUP;
1500 if (ret < 0) {
1501 error_setg(errp,
1502 !bs->read_only && bdrv_is_whitelisted(drv, true)
1503 ? "Driver '%s' can only be used for read-only devices"
1504 : "Driver '%s' is not whitelisted",
1505 drv->format_name);
1506 goto fail_opts;
1510 /* bdrv_new() and bdrv_close() make it so */
1511 assert(atomic_read(&bs->copy_on_read) == 0);
1513 if (bs->open_flags & BDRV_O_COPY_ON_READ) {
1514 if (!bs->read_only) {
1515 bdrv_enable_copy_on_read(bs);
1516 } else {
1517 error_setg(errp, "Can't use copy-on-read on read-only device");
1518 ret = -EINVAL;
1519 goto fail_opts;
1523 discard = qemu_opt_get(opts, BDRV_OPT_DISCARD);
1524 if (discard != NULL) {
1525 if (bdrv_parse_discard_flags(discard, &bs->open_flags) != 0) {
1526 error_setg(errp, "Invalid discard option");
1527 ret = -EINVAL;
1528 goto fail_opts;
1532 bs->detect_zeroes =
1533 bdrv_parse_detect_zeroes(opts, bs->open_flags, &local_err);
1534 if (local_err) {
1535 error_propagate(errp, local_err);
1536 ret = -EINVAL;
1537 goto fail_opts;
1540 if (filename != NULL) {
1541 pstrcpy(bs->filename, sizeof(bs->filename), filename);
1542 } else {
1543 bs->filename[0] = '\0';
1545 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename);
1547 /* Open the image, either directly or using a protocol */
1548 open_flags = bdrv_open_flags(bs, bs->open_flags);
1549 node_name = qemu_opt_get(opts, "node-name");
1551 assert(!drv->bdrv_file_open || file == NULL);
1552 ret = bdrv_open_driver(bs, drv, node_name, options, open_flags, errp);
1553 if (ret < 0) {
1554 goto fail_opts;
1557 qemu_opts_del(opts);
1558 return 0;
1560 fail_opts:
1561 qemu_opts_del(opts);
1562 return ret;
1565 static QDict *parse_json_filename(const char *filename, Error **errp)
1567 QObject *options_obj;
1568 QDict *options;
1569 int ret;
1571 ret = strstart(filename, "json:", &filename);
1572 assert(ret);
1574 options_obj = qobject_from_json(filename, errp);
1575 if (!options_obj) {
1576 error_prepend(errp, "Could not parse the JSON options: ");
1577 return NULL;
1580 options = qobject_to(QDict, options_obj);
1581 if (!options) {
1582 qobject_unref(options_obj);
1583 error_setg(errp, "Invalid JSON object given");
1584 return NULL;
1587 qdict_flatten(options);
1589 return options;
1592 static void parse_json_protocol(QDict *options, const char **pfilename,
1593 Error **errp)
1595 QDict *json_options;
1596 Error *local_err = NULL;
1598 /* Parse json: pseudo-protocol */
1599 if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) {
1600 return;
1603 json_options = parse_json_filename(*pfilename, &local_err);
1604 if (local_err) {
1605 error_propagate(errp, local_err);
1606 return;
1609 /* Options given in the filename have lower priority than options
1610 * specified directly */
1611 qdict_join(options, json_options, false);
1612 qobject_unref(json_options);
1613 *pfilename = NULL;
1617 * Fills in default options for opening images and converts the legacy
1618 * filename/flags pair to option QDict entries.
1619 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1620 * block driver has been specified explicitly.
1622 static int bdrv_fill_options(QDict **options, const char *filename,
1623 int *flags, Error **errp)
1625 const char *drvname;
1626 bool protocol = *flags & BDRV_O_PROTOCOL;
1627 bool parse_filename = false;
1628 BlockDriver *drv = NULL;
1629 Error *local_err = NULL;
1632 * Caution: while qdict_get_try_str() is fine, getting non-string
1633 * types would require more care. When @options come from
1634 * -blockdev or blockdev_add, its members are typed according to
1635 * the QAPI schema, but when they come from -drive, they're all
1636 * QString.
1638 drvname = qdict_get_try_str(*options, "driver");
1639 if (drvname) {
1640 drv = bdrv_find_format(drvname);
1641 if (!drv) {
1642 error_setg(errp, "Unknown driver '%s'", drvname);
1643 return -ENOENT;
1645 /* If the user has explicitly specified the driver, this choice should
1646 * override the BDRV_O_PROTOCOL flag */
1647 protocol = drv->bdrv_file_open;
1650 if (protocol) {
1651 *flags |= BDRV_O_PROTOCOL;
1652 } else {
1653 *flags &= ~BDRV_O_PROTOCOL;
1656 /* Translate cache options from flags into options */
1657 update_options_from_flags(*options, *flags);
1659 /* Fetch the file name from the options QDict if necessary */
1660 if (protocol && filename) {
1661 if (!qdict_haskey(*options, "filename")) {
1662 qdict_put_str(*options, "filename", filename);
1663 parse_filename = true;
1664 } else {
1665 error_setg(errp, "Can't specify 'file' and 'filename' options at "
1666 "the same time");
1667 return -EINVAL;
1671 /* Find the right block driver */
1672 /* See cautionary note on accessing @options above */
1673 filename = qdict_get_try_str(*options, "filename");
1675 if (!drvname && protocol) {
1676 if (filename) {
1677 drv = bdrv_find_protocol(filename, parse_filename, errp);
1678 if (!drv) {
1679 return -EINVAL;
1682 drvname = drv->format_name;
1683 qdict_put_str(*options, "driver", drvname);
1684 } else {
1685 error_setg(errp, "Must specify either driver or file");
1686 return -EINVAL;
1690 assert(drv || !protocol);
1692 /* Driver-specific filename parsing */
1693 if (drv && drv->bdrv_parse_filename && parse_filename) {
1694 drv->bdrv_parse_filename(filename, *options, &local_err);
1695 if (local_err) {
1696 error_propagate(errp, local_err);
1697 return -EINVAL;
1700 if (!drv->bdrv_needs_filename) {
1701 qdict_del(*options, "filename");
1705 return 0;
1708 static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q,
1709 uint64_t perm, uint64_t shared,
1710 GSList *ignore_children,
1711 bool *tighten_restrictions, Error **errp);
1712 static void bdrv_child_abort_perm_update(BdrvChild *c);
1713 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared);
1714 static void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm,
1715 uint64_t *shared_perm);
1717 typedef struct BlockReopenQueueEntry {
1718 bool prepared;
1719 bool perms_checked;
1720 BDRVReopenState state;
1721 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry;
1722 } BlockReopenQueueEntry;
1725 * Return the flags that @bs will have after the reopens in @q have
1726 * successfully completed. If @q is NULL (or @bs is not contained in @q),
1727 * return the current flags.
1729 static int bdrv_reopen_get_flags(BlockReopenQueue *q, BlockDriverState *bs)
1731 BlockReopenQueueEntry *entry;
1733 if (q != NULL) {
1734 QSIMPLEQ_FOREACH(entry, q, entry) {
1735 if (entry->state.bs == bs) {
1736 return entry->state.flags;
1741 return bs->open_flags;
1744 /* Returns whether the image file can be written to after the reopen queue @q
1745 * has been successfully applied, or right now if @q is NULL. */
1746 static bool bdrv_is_writable_after_reopen(BlockDriverState *bs,
1747 BlockReopenQueue *q)
1749 int flags = bdrv_reopen_get_flags(q, bs);
1751 return (flags & (BDRV_O_RDWR | BDRV_O_INACTIVE)) == BDRV_O_RDWR;
1755 * Return whether the BDS can be written to. This is not necessarily
1756 * the same as !bdrv_is_read_only(bs), as inactivated images may not
1757 * be written to but do not count as read-only images.
1759 bool bdrv_is_writable(BlockDriverState *bs)
1761 return bdrv_is_writable_after_reopen(bs, NULL);
1764 static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs,
1765 BdrvChild *c, const BdrvChildRole *role,
1766 BlockReopenQueue *reopen_queue,
1767 uint64_t parent_perm, uint64_t parent_shared,
1768 uint64_t *nperm, uint64_t *nshared)
1770 assert(bs->drv && bs->drv->bdrv_child_perm);
1771 bs->drv->bdrv_child_perm(bs, c, role, reopen_queue,
1772 parent_perm, parent_shared,
1773 nperm, nshared);
1774 /* TODO Take force_share from reopen_queue */
1775 if (child_bs && child_bs->force_share) {
1776 *nshared = BLK_PERM_ALL;
1781 * Check whether permissions on this node can be changed in a way that
1782 * @cumulative_perms and @cumulative_shared_perms are the new cumulative
1783 * permissions of all its parents. This involves checking whether all necessary
1784 * permission changes to child nodes can be performed.
1786 * Will set *tighten_restrictions to true if and only if new permissions have to
1787 * be taken or currently shared permissions are to be unshared. Otherwise,
1788 * errors are not fatal as long as the caller accepts that the restrictions
1789 * remain tighter than they need to be. The caller still has to abort the
1790 * transaction.
1791 * @tighten_restrictions cannot be used together with @q: When reopening, we may
1792 * encounter fatal errors even though no restrictions are to be tightened. For
1793 * example, changing a node from RW to RO will fail if the WRITE permission is
1794 * to be kept.
1796 * A call to this function must always be followed by a call to bdrv_set_perm()
1797 * or bdrv_abort_perm_update().
1799 static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
1800 uint64_t cumulative_perms,
1801 uint64_t cumulative_shared_perms,
1802 GSList *ignore_children,
1803 bool *tighten_restrictions, Error **errp)
1805 BlockDriver *drv = bs->drv;
1806 BdrvChild *c;
1807 int ret;
1809 assert(!q || !tighten_restrictions);
1811 if (tighten_restrictions) {
1812 uint64_t current_perms, current_shared;
1813 uint64_t added_perms, removed_shared_perms;
1815 bdrv_get_cumulative_perm(bs, &current_perms, &current_shared);
1817 added_perms = cumulative_perms & ~current_perms;
1818 removed_shared_perms = current_shared & ~cumulative_shared_perms;
1820 *tighten_restrictions = added_perms || removed_shared_perms;
1823 /* Write permissions never work with read-only images */
1824 if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) &&
1825 !bdrv_is_writable_after_reopen(bs, q))
1827 if (!bdrv_is_writable_after_reopen(bs, NULL)) {
1828 error_setg(errp, "Block node is read-only");
1829 } else {
1830 uint64_t current_perms, current_shared;
1831 bdrv_get_cumulative_perm(bs, &current_perms, &current_shared);
1832 if (current_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) {
1833 error_setg(errp, "Cannot make block node read-only, there is "
1834 "a writer on it");
1835 } else {
1836 error_setg(errp, "Cannot make block node read-only and create "
1837 "a writer on it");
1841 return -EPERM;
1844 /* Check this node */
1845 if (!drv) {
1846 return 0;
1849 if (drv->bdrv_check_perm) {
1850 return drv->bdrv_check_perm(bs, cumulative_perms,
1851 cumulative_shared_perms, errp);
1854 /* Drivers that never have children can omit .bdrv_child_perm() */
1855 if (!drv->bdrv_child_perm) {
1856 assert(QLIST_EMPTY(&bs->children));
1857 return 0;
1860 /* Check all children */
1861 QLIST_FOREACH(c, &bs->children, next) {
1862 uint64_t cur_perm, cur_shared;
1863 bool child_tighten_restr;
1865 bdrv_child_perm(bs, c->bs, c, c->role, q,
1866 cumulative_perms, cumulative_shared_perms,
1867 &cur_perm, &cur_shared);
1868 ret = bdrv_child_check_perm(c, q, cur_perm, cur_shared, ignore_children,
1869 tighten_restrictions ? &child_tighten_restr
1870 : NULL,
1871 errp);
1872 if (tighten_restrictions) {
1873 *tighten_restrictions |= child_tighten_restr;
1875 if (ret < 0) {
1876 return ret;
1880 return 0;
1884 * Notifies drivers that after a previous bdrv_check_perm() call, the
1885 * permission update is not performed and any preparations made for it (e.g.
1886 * taken file locks) need to be undone.
1888 * This function recursively notifies all child nodes.
1890 static void bdrv_abort_perm_update(BlockDriverState *bs)
1892 BlockDriver *drv = bs->drv;
1893 BdrvChild *c;
1895 if (!drv) {
1896 return;
1899 if (drv->bdrv_abort_perm_update) {
1900 drv->bdrv_abort_perm_update(bs);
1903 QLIST_FOREACH(c, &bs->children, next) {
1904 bdrv_child_abort_perm_update(c);
1908 static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms,
1909 uint64_t cumulative_shared_perms)
1911 BlockDriver *drv = bs->drv;
1912 BdrvChild *c;
1914 if (!drv) {
1915 return;
1918 /* Update this node */
1919 if (drv->bdrv_set_perm) {
1920 drv->bdrv_set_perm(bs, cumulative_perms, cumulative_shared_perms);
1923 /* Drivers that never have children can omit .bdrv_child_perm() */
1924 if (!drv->bdrv_child_perm) {
1925 assert(QLIST_EMPTY(&bs->children));
1926 return;
1929 /* Update all children */
1930 QLIST_FOREACH(c, &bs->children, next) {
1931 uint64_t cur_perm, cur_shared;
1932 bdrv_child_perm(bs, c->bs, c, c->role, NULL,
1933 cumulative_perms, cumulative_shared_perms,
1934 &cur_perm, &cur_shared);
1935 bdrv_child_set_perm(c, cur_perm, cur_shared);
1939 static void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm,
1940 uint64_t *shared_perm)
1942 BdrvChild *c;
1943 uint64_t cumulative_perms = 0;
1944 uint64_t cumulative_shared_perms = BLK_PERM_ALL;
1946 QLIST_FOREACH(c, &bs->parents, next_parent) {
1947 cumulative_perms |= c->perm;
1948 cumulative_shared_perms &= c->shared_perm;
1951 *perm = cumulative_perms;
1952 *shared_perm = cumulative_shared_perms;
1955 static char *bdrv_child_user_desc(BdrvChild *c)
1957 if (c->role->get_parent_desc) {
1958 return c->role->get_parent_desc(c);
1961 return g_strdup("another user");
1964 char *bdrv_perm_names(uint64_t perm)
1966 struct perm_name {
1967 uint64_t perm;
1968 const char *name;
1969 } permissions[] = {
1970 { BLK_PERM_CONSISTENT_READ, "consistent read" },
1971 { BLK_PERM_WRITE, "write" },
1972 { BLK_PERM_WRITE_UNCHANGED, "write unchanged" },
1973 { BLK_PERM_RESIZE, "resize" },
1974 { BLK_PERM_GRAPH_MOD, "change children" },
1975 { 0, NULL }
1978 char *result = g_strdup("");
1979 struct perm_name *p;
1981 for (p = permissions; p->name; p++) {
1982 if (perm & p->perm) {
1983 char *old = result;
1984 result = g_strdup_printf("%s%s%s", old, *old ? ", " : "", p->name);
1985 g_free(old);
1989 return result;
1993 * Checks whether a new reference to @bs can be added if the new user requires
1994 * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is
1995 * set, the BdrvChild objects in this list are ignored in the calculations;
1996 * this allows checking permission updates for an existing reference.
1998 * See bdrv_check_perm() for the semantics of @tighten_restrictions.
2000 * Needs to be followed by a call to either bdrv_set_perm() or
2001 * bdrv_abort_perm_update(). */
2002 static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q,
2003 uint64_t new_used_perm,
2004 uint64_t new_shared_perm,
2005 GSList *ignore_children,
2006 bool *tighten_restrictions,
2007 Error **errp)
2009 BdrvChild *c;
2010 uint64_t cumulative_perms = new_used_perm;
2011 uint64_t cumulative_shared_perms = new_shared_perm;
2013 assert(!q || !tighten_restrictions);
2015 /* There is no reason why anyone couldn't tolerate write_unchanged */
2016 assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED);
2018 QLIST_FOREACH(c, &bs->parents, next_parent) {
2019 if (g_slist_find(ignore_children, c)) {
2020 continue;
2023 if ((new_used_perm & c->shared_perm) != new_used_perm) {
2024 char *user = bdrv_child_user_desc(c);
2025 char *perm_names = bdrv_perm_names(new_used_perm & ~c->shared_perm);
2027 if (tighten_restrictions) {
2028 *tighten_restrictions = true;
2031 error_setg(errp, "Conflicts with use by %s as '%s', which does not "
2032 "allow '%s' on %s",
2033 user, c->name, perm_names, bdrv_get_node_name(c->bs));
2034 g_free(user);
2035 g_free(perm_names);
2036 return -EPERM;
2039 if ((c->perm & new_shared_perm) != c->perm) {
2040 char *user = bdrv_child_user_desc(c);
2041 char *perm_names = bdrv_perm_names(c->perm & ~new_shared_perm);
2043 if (tighten_restrictions) {
2044 *tighten_restrictions = true;
2047 error_setg(errp, "Conflicts with use by %s as '%s', which uses "
2048 "'%s' on %s",
2049 user, c->name, perm_names, bdrv_get_node_name(c->bs));
2050 g_free(user);
2051 g_free(perm_names);
2052 return -EPERM;
2055 cumulative_perms |= c->perm;
2056 cumulative_shared_perms &= c->shared_perm;
2059 return bdrv_check_perm(bs, q, cumulative_perms, cumulative_shared_perms,
2060 ignore_children, tighten_restrictions, errp);
2063 /* Needs to be followed by a call to either bdrv_child_set_perm() or
2064 * bdrv_child_abort_perm_update(). */
2065 static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q,
2066 uint64_t perm, uint64_t shared,
2067 GSList *ignore_children,
2068 bool *tighten_restrictions, Error **errp)
2070 int ret;
2072 ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c);
2073 ret = bdrv_check_update_perm(c->bs, q, perm, shared, ignore_children,
2074 tighten_restrictions, errp);
2075 g_slist_free(ignore_children);
2077 if (ret < 0) {
2078 return ret;
2081 if (!c->has_backup_perm) {
2082 c->has_backup_perm = true;
2083 c->backup_perm = c->perm;
2084 c->backup_shared_perm = c->shared_perm;
2087 * Note: it's OK if c->has_backup_perm was already set, as we can find the
2088 * same child twice during check_perm procedure
2091 c->perm = perm;
2092 c->shared_perm = shared;
2094 return 0;
2097 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared)
2099 uint64_t cumulative_perms, cumulative_shared_perms;
2101 c->has_backup_perm = false;
2103 c->perm = perm;
2104 c->shared_perm = shared;
2106 bdrv_get_cumulative_perm(c->bs, &cumulative_perms,
2107 &cumulative_shared_perms);
2108 bdrv_set_perm(c->bs, cumulative_perms, cumulative_shared_perms);
2111 static void bdrv_child_abort_perm_update(BdrvChild *c)
2113 if (c->has_backup_perm) {
2114 c->perm = c->backup_perm;
2115 c->shared_perm = c->backup_shared_perm;
2116 c->has_backup_perm = false;
2119 bdrv_abort_perm_update(c->bs);
2122 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
2123 Error **errp)
2125 Error *local_err = NULL;
2126 int ret;
2127 bool tighten_restrictions;
2129 ret = bdrv_child_check_perm(c, NULL, perm, shared, NULL,
2130 &tighten_restrictions, &local_err);
2131 if (ret < 0) {
2132 bdrv_child_abort_perm_update(c);
2133 if (tighten_restrictions) {
2134 error_propagate(errp, local_err);
2135 } else {
2137 * Our caller may intend to only loosen restrictions and
2138 * does not expect this function to fail. Errors are not
2139 * fatal in such a case, so we can just hide them from our
2140 * caller.
2142 error_free(local_err);
2143 ret = 0;
2145 return ret;
2148 bdrv_child_set_perm(c, perm, shared);
2150 return 0;
2153 int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp)
2155 uint64_t parent_perms, parent_shared;
2156 uint64_t perms, shared;
2158 bdrv_get_cumulative_perm(bs, &parent_perms, &parent_shared);
2159 bdrv_child_perm(bs, c->bs, c, c->role, NULL, parent_perms, parent_shared,
2160 &perms, &shared);
2162 return bdrv_child_try_set_perm(c, perms, shared, errp);
2165 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
2166 const BdrvChildRole *role,
2167 BlockReopenQueue *reopen_queue,
2168 uint64_t perm, uint64_t shared,
2169 uint64_t *nperm, uint64_t *nshared)
2171 if (c == NULL) {
2172 *nperm = perm & DEFAULT_PERM_PASSTHROUGH;
2173 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
2174 return;
2177 *nperm = (perm & DEFAULT_PERM_PASSTHROUGH) |
2178 (c->perm & DEFAULT_PERM_UNCHANGED);
2179 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) |
2180 (c->shared_perm & DEFAULT_PERM_UNCHANGED);
2183 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
2184 const BdrvChildRole *role,
2185 BlockReopenQueue *reopen_queue,
2186 uint64_t perm, uint64_t shared,
2187 uint64_t *nperm, uint64_t *nshared)
2189 bool backing = (role == &child_backing);
2190 assert(role == &child_backing || role == &child_file);
2192 if (!backing) {
2193 int flags = bdrv_reopen_get_flags(reopen_queue, bs);
2195 /* Apart from the modifications below, the same permissions are
2196 * forwarded and left alone as for filters */
2197 bdrv_filter_default_perms(bs, c, role, reopen_queue, perm, shared,
2198 &perm, &shared);
2200 /* Format drivers may touch metadata even if the guest doesn't write */
2201 if (bdrv_is_writable_after_reopen(bs, reopen_queue)) {
2202 perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
2205 /* bs->file always needs to be consistent because of the metadata. We
2206 * can never allow other users to resize or write to it. */
2207 if (!(flags & BDRV_O_NO_IO)) {
2208 perm |= BLK_PERM_CONSISTENT_READ;
2210 shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
2211 } else {
2212 /* We want consistent read from backing files if the parent needs it.
2213 * No other operations are performed on backing files. */
2214 perm &= BLK_PERM_CONSISTENT_READ;
2216 /* If the parent can deal with changing data, we're okay with a
2217 * writable and resizable backing file. */
2218 /* TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? */
2219 if (shared & BLK_PERM_WRITE) {
2220 shared = BLK_PERM_WRITE | BLK_PERM_RESIZE;
2221 } else {
2222 shared = 0;
2225 shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD |
2226 BLK_PERM_WRITE_UNCHANGED;
2229 if (bs->open_flags & BDRV_O_INACTIVE) {
2230 shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
2233 *nperm = perm;
2234 *nshared = shared;
2237 static void bdrv_replace_child_noperm(BdrvChild *child,
2238 BlockDriverState *new_bs)
2240 BlockDriverState *old_bs = child->bs;
2241 int i;
2243 assert(!child->frozen);
2245 if (old_bs && new_bs) {
2246 assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs));
2248 if (old_bs) {
2249 /* Detach first so that the recursive drain sections coming from @child
2250 * are already gone and we only end the drain sections that came from
2251 * elsewhere. */
2252 if (child->role->detach) {
2253 child->role->detach(child);
2255 while (child->parent_quiesce_counter) {
2256 bdrv_parent_drained_end_single(child);
2258 QLIST_REMOVE(child, next_parent);
2259 } else {
2260 assert(child->parent_quiesce_counter == 0);
2263 child->bs = new_bs;
2265 if (new_bs) {
2266 QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
2267 if (new_bs->quiesce_counter) {
2268 int num = new_bs->quiesce_counter;
2269 if (child->role->parent_is_bds) {
2270 num -= bdrv_drain_all_count;
2272 assert(num >= 0);
2273 for (i = 0; i < num; i++) {
2274 bdrv_parent_drained_begin_single(child, true);
2278 /* Attach only after starting new drained sections, so that recursive
2279 * drain sections coming from @child don't get an extra .drained_begin
2280 * callback. */
2281 if (child->role->attach) {
2282 child->role->attach(child);
2288 * Updates @child to change its reference to point to @new_bs, including
2289 * checking and applying the necessary permisson updates both to the old node
2290 * and to @new_bs.
2292 * NULL is passed as @new_bs for removing the reference before freeing @child.
2294 * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this
2295 * function uses bdrv_set_perm() to update the permissions according to the new
2296 * reference that @new_bs gets.
2298 static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
2300 BlockDriverState *old_bs = child->bs;
2301 uint64_t perm, shared_perm;
2303 bdrv_replace_child_noperm(child, new_bs);
2306 * Start with the new node's permissions. If @new_bs is a (direct
2307 * or indirect) child of @old_bs, we must complete the permission
2308 * update on @new_bs before we loosen the restrictions on @old_bs.
2309 * Otherwise, bdrv_check_perm() on @old_bs would re-initiate
2310 * updating the permissions of @new_bs, and thus not purely loosen
2311 * restrictions.
2313 if (new_bs) {
2314 bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm);
2315 bdrv_set_perm(new_bs, perm, shared_perm);
2318 if (old_bs) {
2319 /* Update permissions for old node. This is guaranteed to succeed
2320 * because we're just taking a parent away, so we're loosening
2321 * restrictions. */
2322 bool tighten_restrictions;
2323 int ret;
2325 bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm);
2326 ret = bdrv_check_perm(old_bs, NULL, perm, shared_perm, NULL,
2327 &tighten_restrictions, NULL);
2328 assert(tighten_restrictions == false);
2329 if (ret < 0) {
2330 /* We only tried to loosen restrictions, so errors are not fatal */
2331 bdrv_abort_perm_update(old_bs);
2332 } else {
2333 bdrv_set_perm(old_bs, perm, shared_perm);
2336 /* When the parent requiring a non-default AioContext is removed, the
2337 * node moves back to the main AioContext */
2338 bdrv_try_set_aio_context(old_bs, qemu_get_aio_context(), NULL);
2343 * This function steals the reference to child_bs from the caller.
2344 * That reference is later dropped by bdrv_root_unref_child().
2346 * On failure NULL is returned, errp is set and the reference to
2347 * child_bs is also dropped.
2349 * The caller must hold the AioContext lock @child_bs, but not that of @ctx
2350 * (unless @child_bs is already in @ctx).
2352 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
2353 const char *child_name,
2354 const BdrvChildRole *child_role,
2355 AioContext *ctx,
2356 uint64_t perm, uint64_t shared_perm,
2357 void *opaque, Error **errp)
2359 BdrvChild *child;
2360 Error *local_err = NULL;
2361 int ret;
2363 ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, NULL,
2364 errp);
2365 if (ret < 0) {
2366 bdrv_abort_perm_update(child_bs);
2367 bdrv_unref(child_bs);
2368 return NULL;
2371 child = g_new(BdrvChild, 1);
2372 *child = (BdrvChild) {
2373 .bs = NULL,
2374 .name = g_strdup(child_name),
2375 .role = child_role,
2376 .perm = perm,
2377 .shared_perm = shared_perm,
2378 .opaque = opaque,
2381 /* If the AioContexts don't match, first try to move the subtree of
2382 * child_bs into the AioContext of the new parent. If this doesn't work,
2383 * try moving the parent into the AioContext of child_bs instead. */
2384 if (bdrv_get_aio_context(child_bs) != ctx) {
2385 ret = bdrv_try_set_aio_context(child_bs, ctx, &local_err);
2386 if (ret < 0 && child_role->can_set_aio_ctx) {
2387 GSList *ignore = g_slist_prepend(NULL, child);;
2388 ctx = bdrv_get_aio_context(child_bs);
2389 if (child_role->can_set_aio_ctx(child, ctx, &ignore, NULL)) {
2390 error_free(local_err);
2391 ret = 0;
2392 g_slist_free(ignore);
2393 ignore = g_slist_prepend(NULL, child);;
2394 child_role->set_aio_ctx(child, ctx, &ignore);
2396 g_slist_free(ignore);
2398 if (ret < 0) {
2399 error_propagate(errp, local_err);
2400 g_free(child);
2401 bdrv_abort_perm_update(child_bs);
2402 return NULL;
2406 /* This performs the matching bdrv_set_perm() for the above check. */
2407 bdrv_replace_child(child, child_bs);
2409 return child;
2413 * This function transfers the reference to child_bs from the caller
2414 * to parent_bs. That reference is later dropped by parent_bs on
2415 * bdrv_close() or if someone calls bdrv_unref_child().
2417 * On failure NULL is returned, errp is set and the reference to
2418 * child_bs is also dropped.
2420 * If @parent_bs and @child_bs are in different AioContexts, the caller must
2421 * hold the AioContext lock for @child_bs, but not for @parent_bs.
2423 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
2424 BlockDriverState *child_bs,
2425 const char *child_name,
2426 const BdrvChildRole *child_role,
2427 Error **errp)
2429 BdrvChild *child;
2430 uint64_t perm, shared_perm;
2432 bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm);
2434 assert(parent_bs->drv);
2435 bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL,
2436 perm, shared_perm, &perm, &shared_perm);
2438 child = bdrv_root_attach_child(child_bs, child_name, child_role,
2439 bdrv_get_aio_context(parent_bs),
2440 perm, shared_perm, parent_bs, errp);
2441 if (child == NULL) {
2442 return NULL;
2445 QLIST_INSERT_HEAD(&parent_bs->children, child, next);
2446 return child;
2449 static void bdrv_detach_child(BdrvChild *child)
2451 if (child->next.le_prev) {
2452 QLIST_REMOVE(child, next);
2453 child->next.le_prev = NULL;
2456 bdrv_replace_child(child, NULL);
2458 g_free(child->name);
2459 g_free(child);
2462 void bdrv_root_unref_child(BdrvChild *child)
2464 BlockDriverState *child_bs;
2466 child_bs = child->bs;
2467 bdrv_detach_child(child);
2468 bdrv_unref(child_bs);
2472 * Clear all inherits_from pointers from children and grandchildren of
2473 * @root that point to @root, where necessary.
2475 static void bdrv_unset_inherits_from(BlockDriverState *root, BdrvChild *child)
2477 BdrvChild *c;
2479 if (child->bs->inherits_from == root) {
2481 * Remove inherits_from only when the last reference between root and
2482 * child->bs goes away.
2484 QLIST_FOREACH(c, &root->children, next) {
2485 if (c != child && c->bs == child->bs) {
2486 break;
2489 if (c == NULL) {
2490 child->bs->inherits_from = NULL;
2494 QLIST_FOREACH(c, &child->bs->children, next) {
2495 bdrv_unset_inherits_from(root, c);
2499 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child)
2501 if (child == NULL) {
2502 return;
2505 bdrv_unset_inherits_from(parent, child);
2506 bdrv_root_unref_child(child);
2510 static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load)
2512 BdrvChild *c;
2513 QLIST_FOREACH(c, &bs->parents, next_parent) {
2514 if (c->role->change_media) {
2515 c->role->change_media(c, load);
2520 /* Return true if you can reach parent going through child->inherits_from
2521 * recursively. If parent or child are NULL, return false */
2522 static bool bdrv_inherits_from_recursive(BlockDriverState *child,
2523 BlockDriverState *parent)
2525 while (child && child != parent) {
2526 child = child->inherits_from;
2529 return child != NULL;
2533 * Sets the backing file link of a BDS. A new reference is created; callers
2534 * which don't need their own reference any more must call bdrv_unref().
2536 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
2537 Error **errp)
2539 bool update_inherits_from = bdrv_chain_contains(bs, backing_hd) &&
2540 bdrv_inherits_from_recursive(backing_hd, bs);
2542 if (bdrv_is_backing_chain_frozen(bs, backing_bs(bs), errp)) {
2543 return;
2546 if (backing_hd) {
2547 bdrv_ref(backing_hd);
2550 if (bs->backing) {
2551 bdrv_unref_child(bs, bs->backing);
2554 if (!backing_hd) {
2555 bs->backing = NULL;
2556 goto out;
2559 bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing,
2560 errp);
2561 /* If backing_hd was already part of bs's backing chain, and
2562 * inherits_from pointed recursively to bs then let's update it to
2563 * point directly to bs (else it will become NULL). */
2564 if (bs->backing && update_inherits_from) {
2565 backing_hd->inherits_from = bs;
2568 out:
2569 bdrv_refresh_limits(bs, NULL);
2573 * Opens the backing file for a BlockDriverState if not yet open
2575 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
2576 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2577 * itself, all options starting with "${bdref_key}." are considered part of the
2578 * BlockdevRef.
2580 * TODO Can this be unified with bdrv_open_image()?
2582 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
2583 const char *bdref_key, Error **errp)
2585 char *backing_filename = NULL;
2586 char *bdref_key_dot;
2587 const char *reference = NULL;
2588 int ret = 0;
2589 bool implicit_backing = false;
2590 BlockDriverState *backing_hd;
2591 QDict *options;
2592 QDict *tmp_parent_options = NULL;
2593 Error *local_err = NULL;
2595 if (bs->backing != NULL) {
2596 goto free_exit;
2599 /* NULL means an empty set of options */
2600 if (parent_options == NULL) {
2601 tmp_parent_options = qdict_new();
2602 parent_options = tmp_parent_options;
2605 bs->open_flags &= ~BDRV_O_NO_BACKING;
2607 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
2608 qdict_extract_subqdict(parent_options, &options, bdref_key_dot);
2609 g_free(bdref_key_dot);
2612 * Caution: while qdict_get_try_str() is fine, getting non-string
2613 * types would require more care. When @parent_options come from
2614 * -blockdev or blockdev_add, its members are typed according to
2615 * the QAPI schema, but when they come from -drive, they're all
2616 * QString.
2618 reference = qdict_get_try_str(parent_options, bdref_key);
2619 if (reference || qdict_haskey(options, "file.filename")) {
2620 /* keep backing_filename NULL */
2621 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
2622 qobject_unref(options);
2623 goto free_exit;
2624 } else {
2625 if (qdict_size(options) == 0) {
2626 /* If the user specifies options that do not modify the
2627 * backing file's behavior, we might still consider it the
2628 * implicit backing file. But it's easier this way, and
2629 * just specifying some of the backing BDS's options is
2630 * only possible with -drive anyway (otherwise the QAPI
2631 * schema forces the user to specify everything). */
2632 implicit_backing = !strcmp(bs->auto_backing_file, bs->backing_file);
2635 backing_filename = bdrv_get_full_backing_filename(bs, &local_err);
2636 if (local_err) {
2637 ret = -EINVAL;
2638 error_propagate(errp, local_err);
2639 qobject_unref(options);
2640 goto free_exit;
2644 if (!bs->drv || !bs->drv->supports_backing) {
2645 ret = -EINVAL;
2646 error_setg(errp, "Driver doesn't support backing files");
2647 qobject_unref(options);
2648 goto free_exit;
2651 if (!reference &&
2652 bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) {
2653 qdict_put_str(options, "driver", bs->backing_format);
2656 backing_hd = bdrv_open_inherit(backing_filename, reference, options, 0, bs,
2657 &child_backing, errp);
2658 if (!backing_hd) {
2659 bs->open_flags |= BDRV_O_NO_BACKING;
2660 error_prepend(errp, "Could not open backing file: ");
2661 ret = -EINVAL;
2662 goto free_exit;
2665 if (implicit_backing) {
2666 bdrv_refresh_filename(backing_hd);
2667 pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file),
2668 backing_hd->filename);
2671 /* Hook up the backing file link; drop our reference, bs owns the
2672 * backing_hd reference now */
2673 bdrv_set_backing_hd(bs, backing_hd, &local_err);
2674 bdrv_unref(backing_hd);
2675 if (local_err) {
2676 error_propagate(errp, local_err);
2677 ret = -EINVAL;
2678 goto free_exit;
2681 qdict_del(parent_options, bdref_key);
2683 free_exit:
2684 g_free(backing_filename);
2685 qobject_unref(tmp_parent_options);
2686 return ret;
2689 static BlockDriverState *
2690 bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
2691 BlockDriverState *parent, const BdrvChildRole *child_role,
2692 bool allow_none, Error **errp)
2694 BlockDriverState *bs = NULL;
2695 QDict *image_options;
2696 char *bdref_key_dot;
2697 const char *reference;
2699 assert(child_role != NULL);
2701 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
2702 qdict_extract_subqdict(options, &image_options, bdref_key_dot);
2703 g_free(bdref_key_dot);
2706 * Caution: while qdict_get_try_str() is fine, getting non-string
2707 * types would require more care. When @options come from
2708 * -blockdev or blockdev_add, its members are typed according to
2709 * the QAPI schema, but when they come from -drive, they're all
2710 * QString.
2712 reference = qdict_get_try_str(options, bdref_key);
2713 if (!filename && !reference && !qdict_size(image_options)) {
2714 if (!allow_none) {
2715 error_setg(errp, "A block device must be specified for \"%s\"",
2716 bdref_key);
2718 qobject_unref(image_options);
2719 goto done;
2722 bs = bdrv_open_inherit(filename, reference, image_options, 0,
2723 parent, child_role, errp);
2724 if (!bs) {
2725 goto done;
2728 done:
2729 qdict_del(options, bdref_key);
2730 return bs;
2734 * Opens a disk image whose options are given as BlockdevRef in another block
2735 * device's options.
2737 * If allow_none is true, no image will be opened if filename is false and no
2738 * BlockdevRef is given. NULL will be returned, but errp remains unset.
2740 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
2741 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2742 * itself, all options starting with "${bdref_key}." are considered part of the
2743 * BlockdevRef.
2745 * The BlockdevRef will be removed from the options QDict.
2747 BdrvChild *bdrv_open_child(const char *filename,
2748 QDict *options, const char *bdref_key,
2749 BlockDriverState *parent,
2750 const BdrvChildRole *child_role,
2751 bool allow_none, Error **errp)
2753 BlockDriverState *bs;
2755 bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_role,
2756 allow_none, errp);
2757 if (bs == NULL) {
2758 return NULL;
2761 return bdrv_attach_child(parent, bs, bdref_key, child_role, errp);
2764 /* TODO Future callers may need to specify parent/child_role in order for
2765 * option inheritance to work. Existing callers use it for the root node. */
2766 BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp)
2768 BlockDriverState *bs = NULL;
2769 Error *local_err = NULL;
2770 QObject *obj = NULL;
2771 QDict *qdict = NULL;
2772 const char *reference = NULL;
2773 Visitor *v = NULL;
2775 if (ref->type == QTYPE_QSTRING) {
2776 reference = ref->u.reference;
2777 } else {
2778 BlockdevOptions *options = &ref->u.definition;
2779 assert(ref->type == QTYPE_QDICT);
2781 v = qobject_output_visitor_new(&obj);
2782 visit_type_BlockdevOptions(v, NULL, &options, &local_err);
2783 if (local_err) {
2784 error_propagate(errp, local_err);
2785 goto fail;
2787 visit_complete(v, &obj);
2789 qdict = qobject_to(QDict, obj);
2790 qdict_flatten(qdict);
2792 /* bdrv_open_inherit() defaults to the values in bdrv_flags (for
2793 * compatibility with other callers) rather than what we want as the
2794 * real defaults. Apply the defaults here instead. */
2795 qdict_set_default_str(qdict, BDRV_OPT_CACHE_DIRECT, "off");
2796 qdict_set_default_str(qdict, BDRV_OPT_CACHE_NO_FLUSH, "off");
2797 qdict_set_default_str(qdict, BDRV_OPT_READ_ONLY, "off");
2798 qdict_set_default_str(qdict, BDRV_OPT_AUTO_READ_ONLY, "off");
2802 bs = bdrv_open_inherit(NULL, reference, qdict, 0, NULL, NULL, errp);
2803 obj = NULL;
2805 fail:
2806 qobject_unref(obj);
2807 visit_free(v);
2808 return bs;
2811 static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
2812 int flags,
2813 QDict *snapshot_options,
2814 Error **errp)
2816 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
2817 char *tmp_filename = g_malloc0(PATH_MAX + 1);
2818 int64_t total_size;
2819 QemuOpts *opts = NULL;
2820 BlockDriverState *bs_snapshot = NULL;
2821 Error *local_err = NULL;
2822 int ret;
2824 /* if snapshot, we create a temporary backing file and open it
2825 instead of opening 'filename' directly */
2827 /* Get the required size from the image */
2828 total_size = bdrv_getlength(bs);
2829 if (total_size < 0) {
2830 error_setg_errno(errp, -total_size, "Could not get image size");
2831 goto out;
2834 /* Create the temporary image */
2835 ret = get_tmp_filename(tmp_filename, PATH_MAX + 1);
2836 if (ret < 0) {
2837 error_setg_errno(errp, -ret, "Could not get temporary filename");
2838 goto out;
2841 opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0,
2842 &error_abort);
2843 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort);
2844 ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp);
2845 qemu_opts_del(opts);
2846 if (ret < 0) {
2847 error_prepend(errp, "Could not create temporary overlay '%s': ",
2848 tmp_filename);
2849 goto out;
2852 /* Prepare options QDict for the temporary file */
2853 qdict_put_str(snapshot_options, "file.driver", "file");
2854 qdict_put_str(snapshot_options, "file.filename", tmp_filename);
2855 qdict_put_str(snapshot_options, "driver", "qcow2");
2857 bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp);
2858 snapshot_options = NULL;
2859 if (!bs_snapshot) {
2860 goto out;
2863 /* bdrv_append() consumes a strong reference to bs_snapshot
2864 * (i.e. it will call bdrv_unref() on it) even on error, so in
2865 * order to be able to return one, we have to increase
2866 * bs_snapshot's refcount here */
2867 bdrv_ref(bs_snapshot);
2868 bdrv_append(bs_snapshot, bs, &local_err);
2869 if (local_err) {
2870 error_propagate(errp, local_err);
2871 bs_snapshot = NULL;
2872 goto out;
2875 out:
2876 qobject_unref(snapshot_options);
2877 g_free(tmp_filename);
2878 return bs_snapshot;
2882 * Opens a disk image (raw, qcow2, vmdk, ...)
2884 * options is a QDict of options to pass to the block drivers, or NULL for an
2885 * empty set of options. The reference to the QDict belongs to the block layer
2886 * after the call (even on failure), so if the caller intends to reuse the
2887 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
2889 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
2890 * If it is not NULL, the referenced BDS will be reused.
2892 * The reference parameter may be used to specify an existing block device which
2893 * should be opened. If specified, neither options nor a filename may be given,
2894 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
2896 static BlockDriverState *bdrv_open_inherit(const char *filename,
2897 const char *reference,
2898 QDict *options, int flags,
2899 BlockDriverState *parent,
2900 const BdrvChildRole *child_role,
2901 Error **errp)
2903 int ret;
2904 BlockBackend *file = NULL;
2905 BlockDriverState *bs;
2906 BlockDriver *drv = NULL;
2907 BdrvChild *child;
2908 const char *drvname;
2909 const char *backing;
2910 Error *local_err = NULL;
2911 QDict *snapshot_options = NULL;
2912 int snapshot_flags = 0;
2914 assert(!child_role || !flags);
2915 assert(!child_role == !parent);
2917 if (reference) {
2918 bool options_non_empty = options ? qdict_size(options) : false;
2919 qobject_unref(options);
2921 if (filename || options_non_empty) {
2922 error_setg(errp, "Cannot reference an existing block device with "
2923 "additional options or a new filename");
2924 return NULL;
2927 bs = bdrv_lookup_bs(reference, reference, errp);
2928 if (!bs) {
2929 return NULL;
2932 bdrv_ref(bs);
2933 return bs;
2936 bs = bdrv_new();
2938 /* NULL means an empty set of options */
2939 if (options == NULL) {
2940 options = qdict_new();
2943 /* json: syntax counts as explicit options, as if in the QDict */
2944 parse_json_protocol(options, &filename, &local_err);
2945 if (local_err) {
2946 goto fail;
2949 bs->explicit_options = qdict_clone_shallow(options);
2951 if (child_role) {
2952 bs->inherits_from = parent;
2953 child_role->inherit_options(&flags, options,
2954 parent->open_flags, parent->options);
2957 ret = bdrv_fill_options(&options, filename, &flags, &local_err);
2958 if (local_err) {
2959 goto fail;
2963 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
2964 * Caution: getting a boolean member of @options requires care.
2965 * When @options come from -blockdev or blockdev_add, members are
2966 * typed according to the QAPI schema, but when they come from
2967 * -drive, they're all QString.
2969 if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") &&
2970 !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) {
2971 flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR);
2972 } else {
2973 flags &= ~BDRV_O_RDWR;
2976 if (flags & BDRV_O_SNAPSHOT) {
2977 snapshot_options = qdict_new();
2978 bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options,
2979 flags, options);
2980 /* Let bdrv_backing_options() override "read-only" */
2981 qdict_del(options, BDRV_OPT_READ_ONLY);
2982 bdrv_backing_options(&flags, options, flags, options);
2985 bs->open_flags = flags;
2986 bs->options = options;
2987 options = qdict_clone_shallow(options);
2989 /* Find the right image format driver */
2990 /* See cautionary note on accessing @options above */
2991 drvname = qdict_get_try_str(options, "driver");
2992 if (drvname) {
2993 drv = bdrv_find_format(drvname);
2994 if (!drv) {
2995 error_setg(errp, "Unknown driver: '%s'", drvname);
2996 goto fail;
3000 assert(drvname || !(flags & BDRV_O_PROTOCOL));
3002 /* See cautionary note on accessing @options above */
3003 backing = qdict_get_try_str(options, "backing");
3004 if (qobject_to(QNull, qdict_get(options, "backing")) != NULL ||
3005 (backing && *backing == '\0'))
3007 if (backing) {
3008 warn_report("Use of \"backing\": \"\" is deprecated; "
3009 "use \"backing\": null instead");
3011 flags |= BDRV_O_NO_BACKING;
3012 qdict_del(options, "backing");
3015 /* Open image file without format layer. This BlockBackend is only used for
3016 * probing, the block drivers will do their own bdrv_open_child() for the
3017 * same BDS, which is why we put the node name back into options. */
3018 if ((flags & BDRV_O_PROTOCOL) == 0) {
3019 BlockDriverState *file_bs;
3021 file_bs = bdrv_open_child_bs(filename, options, "file", bs,
3022 &child_file, true, &local_err);
3023 if (local_err) {
3024 goto fail;
3026 if (file_bs != NULL) {
3027 /* Not requesting BLK_PERM_CONSISTENT_READ because we're only
3028 * looking at the header to guess the image format. This works even
3029 * in cases where a guest would not see a consistent state. */
3030 file = blk_new(bdrv_get_aio_context(file_bs), 0, BLK_PERM_ALL);
3031 blk_insert_bs(file, file_bs, &local_err);
3032 bdrv_unref(file_bs);
3033 if (local_err) {
3034 goto fail;
3037 qdict_put_str(options, "file", bdrv_get_node_name(file_bs));
3041 /* Image format probing */
3042 bs->probed = !drv;
3043 if (!drv && file) {
3044 ret = find_image_format(file, filename, &drv, &local_err);
3045 if (ret < 0) {
3046 goto fail;
3049 * This option update would logically belong in bdrv_fill_options(),
3050 * but we first need to open bs->file for the probing to work, while
3051 * opening bs->file already requires the (mostly) final set of options
3052 * so that cache mode etc. can be inherited.
3054 * Adding the driver later is somewhat ugly, but it's not an option
3055 * that would ever be inherited, so it's correct. We just need to make
3056 * sure to update both bs->options (which has the full effective
3057 * options for bs) and options (which has file.* already removed).
3059 qdict_put_str(bs->options, "driver", drv->format_name);
3060 qdict_put_str(options, "driver", drv->format_name);
3061 } else if (!drv) {
3062 error_setg(errp, "Must specify either driver or file");
3063 goto fail;
3066 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
3067 assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open);
3068 /* file must be NULL if a protocol BDS is about to be created
3069 * (the inverse results in an error message from bdrv_open_common()) */
3070 assert(!(flags & BDRV_O_PROTOCOL) || !file);
3072 /* Open the image */
3073 ret = bdrv_open_common(bs, file, options, &local_err);
3074 if (ret < 0) {
3075 goto fail;
3078 if (file) {
3079 blk_unref(file);
3080 file = NULL;
3083 /* If there is a backing file, use it */
3084 if ((flags & BDRV_O_NO_BACKING) == 0) {
3085 ret = bdrv_open_backing_file(bs, options, "backing", &local_err);
3086 if (ret < 0) {
3087 goto close_and_fail;
3091 /* Remove all children options and references
3092 * from bs->options and bs->explicit_options */
3093 QLIST_FOREACH(child, &bs->children, next) {
3094 char *child_key_dot;
3095 child_key_dot = g_strdup_printf("%s.", child->name);
3096 qdict_extract_subqdict(bs->explicit_options, NULL, child_key_dot);
3097 qdict_extract_subqdict(bs->options, NULL, child_key_dot);
3098 qdict_del(bs->explicit_options, child->name);
3099 qdict_del(bs->options, child->name);
3100 g_free(child_key_dot);
3103 /* Check if any unknown options were used */
3104 if (qdict_size(options) != 0) {
3105 const QDictEntry *entry = qdict_first(options);
3106 if (flags & BDRV_O_PROTOCOL) {
3107 error_setg(errp, "Block protocol '%s' doesn't support the option "
3108 "'%s'", drv->format_name, entry->key);
3109 } else {
3110 error_setg(errp,
3111 "Block format '%s' does not support the option '%s'",
3112 drv->format_name, entry->key);
3115 goto close_and_fail;
3118 bdrv_parent_cb_change_media(bs, true);
3120 qobject_unref(options);
3121 options = NULL;
3123 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
3124 * temporary snapshot afterwards. */
3125 if (snapshot_flags) {
3126 BlockDriverState *snapshot_bs;
3127 snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags,
3128 snapshot_options, &local_err);
3129 snapshot_options = NULL;
3130 if (local_err) {
3131 goto close_and_fail;
3133 /* We are not going to return bs but the overlay on top of it
3134 * (snapshot_bs); thus, we have to drop the strong reference to bs
3135 * (which we obtained by calling bdrv_new()). bs will not be deleted,
3136 * though, because the overlay still has a reference to it. */
3137 bdrv_unref(bs);
3138 bs = snapshot_bs;
3141 return bs;
3143 fail:
3144 blk_unref(file);
3145 qobject_unref(snapshot_options);
3146 qobject_unref(bs->explicit_options);
3147 qobject_unref(bs->options);
3148 qobject_unref(options);
3149 bs->options = NULL;
3150 bs->explicit_options = NULL;
3151 bdrv_unref(bs);
3152 error_propagate(errp, local_err);
3153 return NULL;
3155 close_and_fail:
3156 bdrv_unref(bs);
3157 qobject_unref(snapshot_options);
3158 qobject_unref(options);
3159 error_propagate(errp, local_err);
3160 return NULL;
3163 BlockDriverState *bdrv_open(const char *filename, const char *reference,
3164 QDict *options, int flags, Error **errp)
3166 return bdrv_open_inherit(filename, reference, options, flags, NULL,
3167 NULL, errp);
3170 /* Return true if the NULL-terminated @list contains @str */
3171 static bool is_str_in_list(const char *str, const char *const *list)
3173 if (str && list) {
3174 int i;
3175 for (i = 0; list[i] != NULL; i++) {
3176 if (!strcmp(str, list[i])) {
3177 return true;
3181 return false;
3185 * Check that every option set in @bs->options is also set in
3186 * @new_opts.
3188 * Options listed in the common_options list and in
3189 * @bs->drv->mutable_opts are skipped.
3191 * Return 0 on success, otherwise return -EINVAL and set @errp.
3193 static int bdrv_reset_options_allowed(BlockDriverState *bs,
3194 const QDict *new_opts, Error **errp)
3196 const QDictEntry *e;
3197 /* These options are common to all block drivers and are handled
3198 * in bdrv_reopen_prepare() so they can be left out of @new_opts */
3199 const char *const common_options[] = {
3200 "node-name", "discard", "cache.direct", "cache.no-flush",
3201 "read-only", "auto-read-only", "detect-zeroes", NULL
3204 for (e = qdict_first(bs->options); e; e = qdict_next(bs->options, e)) {
3205 if (!qdict_haskey(new_opts, e->key) &&
3206 !is_str_in_list(e->key, common_options) &&
3207 !is_str_in_list(e->key, bs->drv->mutable_opts)) {
3208 error_setg(errp, "Option '%s' cannot be reset "
3209 "to its default value", e->key);
3210 return -EINVAL;
3214 return 0;
3218 * Returns true if @child can be reached recursively from @bs
3220 static bool bdrv_recurse_has_child(BlockDriverState *bs,
3221 BlockDriverState *child)
3223 BdrvChild *c;
3225 if (bs == child) {
3226 return true;
3229 QLIST_FOREACH(c, &bs->children, next) {
3230 if (bdrv_recurse_has_child(c->bs, child)) {
3231 return true;
3235 return false;
3239 * Adds a BlockDriverState to a simple queue for an atomic, transactional
3240 * reopen of multiple devices.
3242 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT
3243 * already performed, or alternatively may be NULL a new BlockReopenQueue will
3244 * be created and initialized. This newly created BlockReopenQueue should be
3245 * passed back in for subsequent calls that are intended to be of the same
3246 * atomic 'set'.
3248 * bs is the BlockDriverState to add to the reopen queue.
3250 * options contains the changed options for the associated bs
3251 * (the BlockReopenQueue takes ownership)
3253 * flags contains the open flags for the associated bs
3255 * returns a pointer to bs_queue, which is either the newly allocated
3256 * bs_queue, or the existing bs_queue being used.
3258 * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple().
3260 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
3261 BlockDriverState *bs,
3262 QDict *options,
3263 const BdrvChildRole *role,
3264 QDict *parent_options,
3265 int parent_flags,
3266 bool keep_old_opts)
3268 assert(bs != NULL);
3270 BlockReopenQueueEntry *bs_entry;
3271 BdrvChild *child;
3272 QDict *old_options, *explicit_options, *options_copy;
3273 int flags;
3274 QemuOpts *opts;
3276 /* Make sure that the caller remembered to use a drained section. This is
3277 * important to avoid graph changes between the recursive queuing here and
3278 * bdrv_reopen_multiple(). */
3279 assert(bs->quiesce_counter > 0);
3281 if (bs_queue == NULL) {
3282 bs_queue = g_new0(BlockReopenQueue, 1);
3283 QSIMPLEQ_INIT(bs_queue);
3286 if (!options) {
3287 options = qdict_new();
3290 /* Check if this BlockDriverState is already in the queue */
3291 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
3292 if (bs == bs_entry->state.bs) {
3293 break;
3298 * Precedence of options:
3299 * 1. Explicitly passed in options (highest)
3300 * 2. Retained from explicitly set options of bs
3301 * 3. Inherited from parent node
3302 * 4. Retained from effective options of bs
3305 /* Old explicitly set values (don't overwrite by inherited value) */
3306 if (bs_entry || keep_old_opts) {
3307 old_options = qdict_clone_shallow(bs_entry ?
3308 bs_entry->state.explicit_options :
3309 bs->explicit_options);
3310 bdrv_join_options(bs, options, old_options);
3311 qobject_unref(old_options);
3314 explicit_options = qdict_clone_shallow(options);
3316 /* Inherit from parent node */
3317 if (parent_options) {
3318 flags = 0;
3319 role->inherit_options(&flags, options, parent_flags, parent_options);
3320 } else {
3321 flags = bdrv_get_flags(bs);
3324 if (keep_old_opts) {
3325 /* Old values are used for options that aren't set yet */
3326 old_options = qdict_clone_shallow(bs->options);
3327 bdrv_join_options(bs, options, old_options);
3328 qobject_unref(old_options);
3331 /* We have the final set of options so let's update the flags */
3332 options_copy = qdict_clone_shallow(options);
3333 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
3334 qemu_opts_absorb_qdict(opts, options_copy, NULL);
3335 update_flags_from_options(&flags, opts);
3336 qemu_opts_del(opts);
3337 qobject_unref(options_copy);
3339 /* bdrv_open_inherit() sets and clears some additional flags internally */
3340 flags &= ~BDRV_O_PROTOCOL;
3341 if (flags & BDRV_O_RDWR) {
3342 flags |= BDRV_O_ALLOW_RDWR;
3345 if (!bs_entry) {
3346 bs_entry = g_new0(BlockReopenQueueEntry, 1);
3347 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry);
3348 } else {
3349 qobject_unref(bs_entry->state.options);
3350 qobject_unref(bs_entry->state.explicit_options);
3353 bs_entry->state.bs = bs;
3354 bs_entry->state.options = options;
3355 bs_entry->state.explicit_options = explicit_options;
3356 bs_entry->state.flags = flags;
3358 /* This needs to be overwritten in bdrv_reopen_prepare() */
3359 bs_entry->state.perm = UINT64_MAX;
3360 bs_entry->state.shared_perm = 0;
3363 * If keep_old_opts is false then it means that unspecified
3364 * options must be reset to their original value. We don't allow
3365 * resetting 'backing' but we need to know if the option is
3366 * missing in order to decide if we have to return an error.
3368 if (!keep_old_opts) {
3369 bs_entry->state.backing_missing =
3370 !qdict_haskey(options, "backing") &&
3371 !qdict_haskey(options, "backing.driver");
3374 QLIST_FOREACH(child, &bs->children, next) {
3375 QDict *new_child_options = NULL;
3376 bool child_keep_old = keep_old_opts;
3378 /* reopen can only change the options of block devices that were
3379 * implicitly created and inherited options. For other (referenced)
3380 * block devices, a syntax like "backing.foo" results in an error. */
3381 if (child->bs->inherits_from != bs) {
3382 continue;
3385 /* Check if the options contain a child reference */
3386 if (qdict_haskey(options, child->name)) {
3387 const char *childref = qdict_get_try_str(options, child->name);
3389 * The current child must not be reopened if the child
3390 * reference is null or points to a different node.
3392 if (g_strcmp0(childref, child->bs->node_name)) {
3393 continue;
3396 * If the child reference points to the current child then
3397 * reopen it with its existing set of options (note that
3398 * it can still inherit new options from the parent).
3400 child_keep_old = true;
3401 } else {
3402 /* Extract child options ("child-name.*") */
3403 char *child_key_dot = g_strdup_printf("%s.", child->name);
3404 qdict_extract_subqdict(explicit_options, NULL, child_key_dot);
3405 qdict_extract_subqdict(options, &new_child_options, child_key_dot);
3406 g_free(child_key_dot);
3409 bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options,
3410 child->role, options, flags, child_keep_old);
3413 return bs_queue;
3416 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
3417 BlockDriverState *bs,
3418 QDict *options, bool keep_old_opts)
3420 return bdrv_reopen_queue_child(bs_queue, bs, options, NULL, NULL, 0,
3421 keep_old_opts);
3425 * Reopen multiple BlockDriverStates atomically & transactionally.
3427 * The queue passed in (bs_queue) must have been built up previous
3428 * via bdrv_reopen_queue().
3430 * Reopens all BDS specified in the queue, with the appropriate
3431 * flags. All devices are prepared for reopen, and failure of any
3432 * device will cause all device changes to be abandoned, and intermediate
3433 * data cleaned up.
3435 * If all devices prepare successfully, then the changes are committed
3436 * to all devices.
3438 * All affected nodes must be drained between bdrv_reopen_queue() and
3439 * bdrv_reopen_multiple().
3441 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
3443 int ret = -1;
3444 BlockReopenQueueEntry *bs_entry, *next;
3446 assert(bs_queue != NULL);
3448 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
3449 assert(bs_entry->state.bs->quiesce_counter > 0);
3450 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, errp)) {
3451 goto cleanup;
3453 bs_entry->prepared = true;
3456 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
3457 BDRVReopenState *state = &bs_entry->state;
3458 ret = bdrv_check_perm(state->bs, bs_queue, state->perm,
3459 state->shared_perm, NULL, NULL, errp);
3460 if (ret < 0) {
3461 goto cleanup_perm;
3463 /* Check if new_backing_bs would accept the new permissions */
3464 if (state->replace_backing_bs && state->new_backing_bs) {
3465 uint64_t nperm, nshared;
3466 bdrv_child_perm(state->bs, state->new_backing_bs,
3467 NULL, &child_backing, bs_queue,
3468 state->perm, state->shared_perm,
3469 &nperm, &nshared);
3470 ret = bdrv_check_update_perm(state->new_backing_bs, NULL,
3471 nperm, nshared, NULL, NULL, errp);
3472 if (ret < 0) {
3473 goto cleanup_perm;
3476 bs_entry->perms_checked = true;
3479 /* If we reach this point, we have success and just need to apply the
3480 * changes
3482 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
3483 bdrv_reopen_commit(&bs_entry->state);
3486 ret = 0;
3487 cleanup_perm:
3488 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
3489 BDRVReopenState *state = &bs_entry->state;
3491 if (!bs_entry->perms_checked) {
3492 continue;
3495 if (ret == 0) {
3496 bdrv_set_perm(state->bs, state->perm, state->shared_perm);
3497 } else {
3498 bdrv_abort_perm_update(state->bs);
3499 if (state->replace_backing_bs && state->new_backing_bs) {
3500 bdrv_abort_perm_update(state->new_backing_bs);
3504 cleanup:
3505 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
3506 if (ret) {
3507 if (bs_entry->prepared) {
3508 bdrv_reopen_abort(&bs_entry->state);
3510 qobject_unref(bs_entry->state.explicit_options);
3511 qobject_unref(bs_entry->state.options);
3513 if (bs_entry->state.new_backing_bs) {
3514 bdrv_unref(bs_entry->state.new_backing_bs);
3516 g_free(bs_entry);
3518 g_free(bs_queue);
3520 return ret;
3523 int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
3524 Error **errp)
3526 int ret;
3527 BlockReopenQueue *queue;
3528 QDict *opts = qdict_new();
3530 qdict_put_bool(opts, BDRV_OPT_READ_ONLY, read_only);
3532 bdrv_subtree_drained_begin(bs);
3533 queue = bdrv_reopen_queue(NULL, bs, opts, true);
3534 ret = bdrv_reopen_multiple(queue, errp);
3535 bdrv_subtree_drained_end(bs);
3537 return ret;
3540 static BlockReopenQueueEntry *find_parent_in_reopen_queue(BlockReopenQueue *q,
3541 BdrvChild *c)
3543 BlockReopenQueueEntry *entry;
3545 QSIMPLEQ_FOREACH(entry, q, entry) {
3546 BlockDriverState *bs = entry->state.bs;
3547 BdrvChild *child;
3549 QLIST_FOREACH(child, &bs->children, next) {
3550 if (child == c) {
3551 return entry;
3556 return NULL;
3559 static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs,
3560 uint64_t *perm, uint64_t *shared)
3562 BdrvChild *c;
3563 BlockReopenQueueEntry *parent;
3564 uint64_t cumulative_perms = 0;
3565 uint64_t cumulative_shared_perms = BLK_PERM_ALL;
3567 QLIST_FOREACH(c, &bs->parents, next_parent) {
3568 parent = find_parent_in_reopen_queue(q, c);
3569 if (!parent) {
3570 cumulative_perms |= c->perm;
3571 cumulative_shared_perms &= c->shared_perm;
3572 } else {
3573 uint64_t nperm, nshared;
3575 bdrv_child_perm(parent->state.bs, bs, c, c->role, q,
3576 parent->state.perm, parent->state.shared_perm,
3577 &nperm, &nshared);
3579 cumulative_perms |= nperm;
3580 cumulative_shared_perms &= nshared;
3583 *perm = cumulative_perms;
3584 *shared = cumulative_shared_perms;
3588 * Take a BDRVReopenState and check if the value of 'backing' in the
3589 * reopen_state->options QDict is valid or not.
3591 * If 'backing' is missing from the QDict then return 0.
3593 * If 'backing' contains the node name of the backing file of
3594 * reopen_state->bs then return 0.
3596 * If 'backing' contains a different node name (or is null) then check
3597 * whether the current backing file can be replaced with the new one.
3598 * If that's the case then reopen_state->replace_backing_bs is set to
3599 * true and reopen_state->new_backing_bs contains a pointer to the new
3600 * backing BlockDriverState (or NULL).
3602 * Return 0 on success, otherwise return < 0 and set @errp.
3604 static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state,
3605 Error **errp)
3607 BlockDriverState *bs = reopen_state->bs;
3608 BlockDriverState *overlay_bs, *new_backing_bs;
3609 QObject *value;
3610 const char *str;
3612 value = qdict_get(reopen_state->options, "backing");
3613 if (value == NULL) {
3614 return 0;
3617 switch (qobject_type(value)) {
3618 case QTYPE_QNULL:
3619 new_backing_bs = NULL;
3620 break;
3621 case QTYPE_QSTRING:
3622 str = qobject_get_try_str(value);
3623 new_backing_bs = bdrv_lookup_bs(NULL, str, errp);
3624 if (new_backing_bs == NULL) {
3625 return -EINVAL;
3626 } else if (bdrv_recurse_has_child(new_backing_bs, bs)) {
3627 error_setg(errp, "Making '%s' a backing file of '%s' "
3628 "would create a cycle", str, bs->node_name);
3629 return -EINVAL;
3631 break;
3632 default:
3633 /* 'backing' does not allow any other data type */
3634 g_assert_not_reached();
3638 * TODO: before removing the x- prefix from x-blockdev-reopen we
3639 * should move the new backing file into the right AioContext
3640 * instead of returning an error.
3642 if (new_backing_bs) {
3643 if (bdrv_get_aio_context(new_backing_bs) != bdrv_get_aio_context(bs)) {
3644 error_setg(errp, "Cannot use a new backing file "
3645 "with a different AioContext");
3646 return -EINVAL;
3651 * Find the "actual" backing file by skipping all links that point
3652 * to an implicit node, if any (e.g. a commit filter node).
3654 overlay_bs = bs;
3655 while (backing_bs(overlay_bs) && backing_bs(overlay_bs)->implicit) {
3656 overlay_bs = backing_bs(overlay_bs);
3659 /* If we want to replace the backing file we need some extra checks */
3660 if (new_backing_bs != backing_bs(overlay_bs)) {
3661 /* Check for implicit nodes between bs and its backing file */
3662 if (bs != overlay_bs) {
3663 error_setg(errp, "Cannot change backing link if '%s' has "
3664 "an implicit backing file", bs->node_name);
3665 return -EPERM;
3667 /* Check if the backing link that we want to replace is frozen */
3668 if (bdrv_is_backing_chain_frozen(overlay_bs, backing_bs(overlay_bs),
3669 errp)) {
3670 return -EPERM;
3672 reopen_state->replace_backing_bs = true;
3673 if (new_backing_bs) {
3674 bdrv_ref(new_backing_bs);
3675 reopen_state->new_backing_bs = new_backing_bs;
3679 return 0;
3683 * Prepares a BlockDriverState for reopen. All changes are staged in the
3684 * 'opaque' field of the BDRVReopenState, which is used and allocated by
3685 * the block driver layer .bdrv_reopen_prepare()
3687 * bs is the BlockDriverState to reopen
3688 * flags are the new open flags
3689 * queue is the reopen queue
3691 * Returns 0 on success, non-zero on error. On error errp will be set
3692 * as well.
3694 * On failure, bdrv_reopen_abort() will be called to clean up any data.
3695 * It is the responsibility of the caller to then call the abort() or
3696 * commit() for any other BDS that have been left in a prepare() state
3699 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
3700 Error **errp)
3702 int ret = -1;
3703 int old_flags;
3704 Error *local_err = NULL;
3705 BlockDriver *drv;
3706 QemuOpts *opts;
3707 QDict *orig_reopen_opts;
3708 char *discard = NULL;
3709 bool read_only;
3710 bool drv_prepared = false;
3712 assert(reopen_state != NULL);
3713 assert(reopen_state->bs->drv != NULL);
3714 drv = reopen_state->bs->drv;
3716 /* This function and each driver's bdrv_reopen_prepare() remove
3717 * entries from reopen_state->options as they are processed, so
3718 * we need to make a copy of the original QDict. */
3719 orig_reopen_opts = qdict_clone_shallow(reopen_state->options);
3721 /* Process generic block layer options */
3722 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
3723 qemu_opts_absorb_qdict(opts, reopen_state->options, &local_err);
3724 if (local_err) {
3725 error_propagate(errp, local_err);
3726 ret = -EINVAL;
3727 goto error;
3730 /* This was already called in bdrv_reopen_queue_child() so the flags
3731 * are up-to-date. This time we simply want to remove the options from
3732 * QemuOpts in order to indicate that they have been processed. */
3733 old_flags = reopen_state->flags;
3734 update_flags_from_options(&reopen_state->flags, opts);
3735 assert(old_flags == reopen_state->flags);
3737 discard = qemu_opt_get_del(opts, BDRV_OPT_DISCARD);
3738 if (discard != NULL) {
3739 if (bdrv_parse_discard_flags(discard, &reopen_state->flags) != 0) {
3740 error_setg(errp, "Invalid discard option");
3741 ret = -EINVAL;
3742 goto error;
3746 reopen_state->detect_zeroes =
3747 bdrv_parse_detect_zeroes(opts, reopen_state->flags, &local_err);
3748 if (local_err) {
3749 error_propagate(errp, local_err);
3750 ret = -EINVAL;
3751 goto error;
3754 /* All other options (including node-name and driver) must be unchanged.
3755 * Put them back into the QDict, so that they are checked at the end
3756 * of this function. */
3757 qemu_opts_to_qdict(opts, reopen_state->options);
3759 /* If we are to stay read-only, do not allow permission change
3760 * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is
3761 * not set, or if the BDS still has copy_on_read enabled */
3762 read_only = !(reopen_state->flags & BDRV_O_RDWR);
3763 ret = bdrv_can_set_read_only(reopen_state->bs, read_only, true, &local_err);
3764 if (local_err) {
3765 error_propagate(errp, local_err);
3766 goto error;
3769 /* Calculate required permissions after reopening */
3770 bdrv_reopen_perm(queue, reopen_state->bs,
3771 &reopen_state->perm, &reopen_state->shared_perm);
3773 ret = bdrv_flush(reopen_state->bs);
3774 if (ret) {
3775 error_setg_errno(errp, -ret, "Error flushing drive");
3776 goto error;
3779 if (drv->bdrv_reopen_prepare) {
3781 * If a driver-specific option is missing, it means that we
3782 * should reset it to its default value.
3783 * But not all options allow that, so we need to check it first.
3785 ret = bdrv_reset_options_allowed(reopen_state->bs,
3786 reopen_state->options, errp);
3787 if (ret) {
3788 goto error;
3791 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err);
3792 if (ret) {
3793 if (local_err != NULL) {
3794 error_propagate(errp, local_err);
3795 } else {
3796 bdrv_refresh_filename(reopen_state->bs);
3797 error_setg(errp, "failed while preparing to reopen image '%s'",
3798 reopen_state->bs->filename);
3800 goto error;
3802 } else {
3803 /* It is currently mandatory to have a bdrv_reopen_prepare()
3804 * handler for each supported drv. */
3805 error_setg(errp, "Block format '%s' used by node '%s' "
3806 "does not support reopening files", drv->format_name,
3807 bdrv_get_device_or_node_name(reopen_state->bs));
3808 ret = -1;
3809 goto error;
3812 drv_prepared = true;
3815 * We must provide the 'backing' option if the BDS has a backing
3816 * file or if the image file has a backing file name as part of
3817 * its metadata. Otherwise the 'backing' option can be omitted.
3819 if (drv->supports_backing && reopen_state->backing_missing &&
3820 (backing_bs(reopen_state->bs) || reopen_state->bs->backing_file[0])) {
3821 error_setg(errp, "backing is missing for '%s'",
3822 reopen_state->bs->node_name);
3823 ret = -EINVAL;
3824 goto error;
3828 * Allow changing the 'backing' option. The new value can be
3829 * either a reference to an existing node (using its node name)
3830 * or NULL to simply detach the current backing file.
3832 ret = bdrv_reopen_parse_backing(reopen_state, errp);
3833 if (ret < 0) {
3834 goto error;
3836 qdict_del(reopen_state->options, "backing");
3838 /* Options that are not handled are only okay if they are unchanged
3839 * compared to the old state. It is expected that some options are only
3840 * used for the initial open, but not reopen (e.g. filename) */
3841 if (qdict_size(reopen_state->options)) {
3842 const QDictEntry *entry = qdict_first(reopen_state->options);
3844 do {
3845 QObject *new = entry->value;
3846 QObject *old = qdict_get(reopen_state->bs->options, entry->key);
3848 /* Allow child references (child_name=node_name) as long as they
3849 * point to the current child (i.e. everything stays the same). */
3850 if (qobject_type(new) == QTYPE_QSTRING) {
3851 BdrvChild *child;
3852 QLIST_FOREACH(child, &reopen_state->bs->children, next) {
3853 if (!strcmp(child->name, entry->key)) {
3854 break;
3858 if (child) {
3859 const char *str = qobject_get_try_str(new);
3860 if (!strcmp(child->bs->node_name, str)) {
3861 continue; /* Found child with this name, skip option */
3867 * TODO: When using -drive to specify blockdev options, all values
3868 * will be strings; however, when using -blockdev, blockdev-add or
3869 * filenames using the json:{} pseudo-protocol, they will be
3870 * correctly typed.
3871 * In contrast, reopening options are (currently) always strings
3872 * (because you can only specify them through qemu-io; all other
3873 * callers do not specify any options).
3874 * Therefore, when using anything other than -drive to create a BDS,
3875 * this cannot detect non-string options as unchanged, because
3876 * qobject_is_equal() always returns false for objects of different
3877 * type. In the future, this should be remedied by correctly typing
3878 * all options. For now, this is not too big of an issue because
3879 * the user can simply omit options which cannot be changed anyway,
3880 * so they will stay unchanged.
3882 if (!qobject_is_equal(new, old)) {
3883 error_setg(errp, "Cannot change the option '%s'", entry->key);
3884 ret = -EINVAL;
3885 goto error;
3887 } while ((entry = qdict_next(reopen_state->options, entry)));
3890 ret = 0;
3892 /* Restore the original reopen_state->options QDict */
3893 qobject_unref(reopen_state->options);
3894 reopen_state->options = qobject_ref(orig_reopen_opts);
3896 error:
3897 if (ret < 0 && drv_prepared) {
3898 /* drv->bdrv_reopen_prepare() has succeeded, so we need to
3899 * call drv->bdrv_reopen_abort() before signaling an error
3900 * (bdrv_reopen_multiple() will not call bdrv_reopen_abort()
3901 * when the respective bdrv_reopen_prepare() has failed) */
3902 if (drv->bdrv_reopen_abort) {
3903 drv->bdrv_reopen_abort(reopen_state);
3906 qemu_opts_del(opts);
3907 qobject_unref(orig_reopen_opts);
3908 g_free(discard);
3909 return ret;
3913 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
3914 * makes them final by swapping the staging BlockDriverState contents into
3915 * the active BlockDriverState contents.
3917 void bdrv_reopen_commit(BDRVReopenState *reopen_state)
3919 BlockDriver *drv;
3920 BlockDriverState *bs;
3921 BdrvChild *child;
3922 bool old_can_write, new_can_write;
3924 assert(reopen_state != NULL);
3925 bs = reopen_state->bs;
3926 drv = bs->drv;
3927 assert(drv != NULL);
3929 old_can_write =
3930 !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE);
3932 /* If there are any driver level actions to take */
3933 if (drv->bdrv_reopen_commit) {
3934 drv->bdrv_reopen_commit(reopen_state);
3937 /* set BDS specific flags now */
3938 qobject_unref(bs->explicit_options);
3939 qobject_unref(bs->options);
3941 bs->explicit_options = reopen_state->explicit_options;
3942 bs->options = reopen_state->options;
3943 bs->open_flags = reopen_state->flags;
3944 bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
3945 bs->detect_zeroes = reopen_state->detect_zeroes;
3947 if (reopen_state->replace_backing_bs) {
3948 qdict_del(bs->explicit_options, "backing");
3949 qdict_del(bs->options, "backing");
3952 /* Remove child references from bs->options and bs->explicit_options.
3953 * Child options were already removed in bdrv_reopen_queue_child() */
3954 QLIST_FOREACH(child, &bs->children, next) {
3955 qdict_del(bs->explicit_options, child->name);
3956 qdict_del(bs->options, child->name);
3960 * Change the backing file if a new one was specified. We do this
3961 * after updating bs->options, so bdrv_refresh_filename() (called
3962 * from bdrv_set_backing_hd()) has the new values.
3964 if (reopen_state->replace_backing_bs) {
3965 BlockDriverState *old_backing_bs = backing_bs(bs);
3966 assert(!old_backing_bs || !old_backing_bs->implicit);
3967 /* Abort the permission update on the backing bs we're detaching */
3968 if (old_backing_bs) {
3969 bdrv_abort_perm_update(old_backing_bs);
3971 bdrv_set_backing_hd(bs, reopen_state->new_backing_bs, &error_abort);
3974 bdrv_refresh_limits(bs, NULL);
3976 new_can_write =
3977 !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE);
3978 if (!old_can_write && new_can_write && drv->bdrv_reopen_bitmaps_rw) {
3979 Error *local_err = NULL;
3980 if (drv->bdrv_reopen_bitmaps_rw(bs, &local_err) < 0) {
3981 /* This is not fatal, bitmaps just left read-only, so all following
3982 * writes will fail. User can remove read-only bitmaps to unblock
3983 * writes.
3985 error_reportf_err(local_err,
3986 "%s: Failed to make dirty bitmaps writable: ",
3987 bdrv_get_node_name(bs));
3993 * Abort the reopen, and delete and free the staged changes in
3994 * reopen_state
3996 void bdrv_reopen_abort(BDRVReopenState *reopen_state)
3998 BlockDriver *drv;
4000 assert(reopen_state != NULL);
4001 drv = reopen_state->bs->drv;
4002 assert(drv != NULL);
4004 if (drv->bdrv_reopen_abort) {
4005 drv->bdrv_reopen_abort(reopen_state);
4010 static void bdrv_close(BlockDriverState *bs)
4012 BdrvAioNotifier *ban, *ban_next;
4013 BdrvChild *child, *next;
4015 assert(!bs->refcnt);
4017 bdrv_drained_begin(bs); /* complete I/O */
4018 bdrv_flush(bs);
4019 bdrv_drain(bs); /* in case flush left pending I/O */
4021 if (bs->drv) {
4022 if (bs->drv->bdrv_close) {
4023 bs->drv->bdrv_close(bs);
4025 bs->drv = NULL;
4028 QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
4029 bdrv_unref_child(bs, child);
4032 bs->backing = NULL;
4033 bs->file = NULL;
4034 g_free(bs->opaque);
4035 bs->opaque = NULL;
4036 atomic_set(&bs->copy_on_read, 0);
4037 bs->backing_file[0] = '\0';
4038 bs->backing_format[0] = '\0';
4039 bs->total_sectors = 0;
4040 bs->encrypted = false;
4041 bs->sg = false;
4042 qobject_unref(bs->options);
4043 qobject_unref(bs->explicit_options);
4044 bs->options = NULL;
4045 bs->explicit_options = NULL;
4046 qobject_unref(bs->full_open_options);
4047 bs->full_open_options = NULL;
4049 bdrv_release_named_dirty_bitmaps(bs);
4050 assert(QLIST_EMPTY(&bs->dirty_bitmaps));
4052 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
4053 g_free(ban);
4055 QLIST_INIT(&bs->aio_notifiers);
4056 bdrv_drained_end(bs);
4059 void bdrv_close_all(void)
4061 assert(job_next(NULL) == NULL);
4062 nbd_export_close_all();
4064 /* Drop references from requests still in flight, such as canceled block
4065 * jobs whose AIO context has not been polled yet */
4066 bdrv_drain_all();
4068 blk_remove_all_bs();
4069 blockdev_close_all_bdrv_states();
4071 assert(QTAILQ_EMPTY(&all_bdrv_states));
4074 static bool should_update_child(BdrvChild *c, BlockDriverState *to)
4076 GQueue *queue;
4077 GHashTable *found;
4078 bool ret;
4080 if (c->role->stay_at_node) {
4081 return false;
4084 /* If the child @c belongs to the BDS @to, replacing the current
4085 * c->bs by @to would mean to create a loop.
4087 * Such a case occurs when appending a BDS to a backing chain.
4088 * For instance, imagine the following chain:
4090 * guest device -> node A -> further backing chain...
4092 * Now we create a new BDS B which we want to put on top of this
4093 * chain, so we first attach A as its backing node:
4095 * node B
4098 * guest device -> node A -> further backing chain...
4100 * Finally we want to replace A by B. When doing that, we want to
4101 * replace all pointers to A by pointers to B -- except for the
4102 * pointer from B because (1) that would create a loop, and (2)
4103 * that pointer should simply stay intact:
4105 * guest device -> node B
4108 * node A -> further backing chain...
4110 * In general, when replacing a node A (c->bs) by a node B (@to),
4111 * if A is a child of B, that means we cannot replace A by B there
4112 * because that would create a loop. Silently detaching A from B
4113 * is also not really an option. So overall just leaving A in
4114 * place there is the most sensible choice.
4116 * We would also create a loop in any cases where @c is only
4117 * indirectly referenced by @to. Prevent this by returning false
4118 * if @c is found (by breadth-first search) anywhere in the whole
4119 * subtree of @to.
4122 ret = true;
4123 found = g_hash_table_new(NULL, NULL);
4124 g_hash_table_add(found, to);
4125 queue = g_queue_new();
4126 g_queue_push_tail(queue, to);
4128 while (!g_queue_is_empty(queue)) {
4129 BlockDriverState *v = g_queue_pop_head(queue);
4130 BdrvChild *c2;
4132 QLIST_FOREACH(c2, &v->children, next) {
4133 if (c2 == c) {
4134 ret = false;
4135 break;
4138 if (g_hash_table_contains(found, c2->bs)) {
4139 continue;
4142 g_queue_push_tail(queue, c2->bs);
4143 g_hash_table_add(found, c2->bs);
4147 g_queue_free(queue);
4148 g_hash_table_destroy(found);
4150 return ret;
4153 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
4154 Error **errp)
4156 BdrvChild *c, *next;
4157 GSList *list = NULL, *p;
4158 uint64_t old_perm, old_shared;
4159 uint64_t perm = 0, shared = BLK_PERM_ALL;
4160 int ret;
4162 /* Make sure that @from doesn't go away until we have successfully attached
4163 * all of its parents to @to. */
4164 bdrv_ref(from);
4166 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
4167 bdrv_drained_begin(from);
4169 /* Put all parents into @list and calculate their cumulative permissions */
4170 QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
4171 assert(c->bs == from);
4172 if (!should_update_child(c, to)) {
4173 continue;
4175 if (c->frozen) {
4176 error_setg(errp, "Cannot change '%s' link to '%s'",
4177 c->name, from->node_name);
4178 goto out;
4180 list = g_slist_prepend(list, c);
4181 perm |= c->perm;
4182 shared &= c->shared_perm;
4185 /* Check whether the required permissions can be granted on @to, ignoring
4186 * all BdrvChild in @list so that they can't block themselves. */
4187 ret = bdrv_check_update_perm(to, NULL, perm, shared, list, NULL, errp);
4188 if (ret < 0) {
4189 bdrv_abort_perm_update(to);
4190 goto out;
4193 /* Now actually perform the change. We performed the permission check for
4194 * all elements of @list at once, so set the permissions all at once at the
4195 * very end. */
4196 for (p = list; p != NULL; p = p->next) {
4197 c = p->data;
4199 bdrv_ref(to);
4200 bdrv_replace_child_noperm(c, to);
4201 bdrv_unref(from);
4204 bdrv_get_cumulative_perm(to, &old_perm, &old_shared);
4205 bdrv_set_perm(to, old_perm | perm, old_shared | shared);
4207 out:
4208 g_slist_free(list);
4209 bdrv_drained_end(from);
4210 bdrv_unref(from);
4214 * Add new bs contents at the top of an image chain while the chain is
4215 * live, while keeping required fields on the top layer.
4217 * This will modify the BlockDriverState fields, and swap contents
4218 * between bs_new and bs_top. Both bs_new and bs_top are modified.
4220 * bs_new must not be attached to a BlockBackend.
4222 * This function does not create any image files.
4224 * bdrv_append() takes ownership of a bs_new reference and unrefs it because
4225 * that's what the callers commonly need. bs_new will be referenced by the old
4226 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a
4227 * reference of its own, it must call bdrv_ref().
4229 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
4230 Error **errp)
4232 Error *local_err = NULL;
4234 bdrv_set_backing_hd(bs_new, bs_top, &local_err);
4235 if (local_err) {
4236 error_propagate(errp, local_err);
4237 goto out;
4240 bdrv_replace_node(bs_top, bs_new, &local_err);
4241 if (local_err) {
4242 error_propagate(errp, local_err);
4243 bdrv_set_backing_hd(bs_new, NULL, &error_abort);
4244 goto out;
4247 /* bs_new is now referenced by its new parents, we don't need the
4248 * additional reference any more. */
4249 out:
4250 bdrv_unref(bs_new);
4253 static void bdrv_delete(BlockDriverState *bs)
4255 assert(bdrv_op_blocker_is_empty(bs));
4256 assert(!bs->refcnt);
4258 /* remove from list, if necessary */
4259 if (bs->node_name[0] != '\0') {
4260 QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list);
4262 QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list);
4264 bdrv_close(bs);
4266 g_free(bs);
4270 * Run consistency checks on an image
4272 * Returns 0 if the check could be completed (it doesn't mean that the image is
4273 * free of errors) or -errno when an internal error occurred. The results of the
4274 * check are stored in res.
4276 static int coroutine_fn bdrv_co_check(BlockDriverState *bs,
4277 BdrvCheckResult *res, BdrvCheckMode fix)
4279 if (bs->drv == NULL) {
4280 return -ENOMEDIUM;
4282 if (bs->drv->bdrv_co_check == NULL) {
4283 return -ENOTSUP;
4286 memset(res, 0, sizeof(*res));
4287 return bs->drv->bdrv_co_check(bs, res, fix);
4290 typedef struct CheckCo {
4291 BlockDriverState *bs;
4292 BdrvCheckResult *res;
4293 BdrvCheckMode fix;
4294 int ret;
4295 } CheckCo;
4297 static void coroutine_fn bdrv_check_co_entry(void *opaque)
4299 CheckCo *cco = opaque;
4300 cco->ret = bdrv_co_check(cco->bs, cco->res, cco->fix);
4301 aio_wait_kick();
4304 int bdrv_check(BlockDriverState *bs,
4305 BdrvCheckResult *res, BdrvCheckMode fix)
4307 Coroutine *co;
4308 CheckCo cco = {
4309 .bs = bs,
4310 .res = res,
4311 .ret = -EINPROGRESS,
4312 .fix = fix,
4315 if (qemu_in_coroutine()) {
4316 /* Fast-path if already in coroutine context */
4317 bdrv_check_co_entry(&cco);
4318 } else {
4319 co = qemu_coroutine_create(bdrv_check_co_entry, &cco);
4320 bdrv_coroutine_enter(bs, co);
4321 BDRV_POLL_WHILE(bs, cco.ret == -EINPROGRESS);
4324 return cco.ret;
4328 * Return values:
4329 * 0 - success
4330 * -EINVAL - backing format specified, but no file
4331 * -ENOSPC - can't update the backing file because no space is left in the
4332 * image file header
4333 * -ENOTSUP - format driver doesn't support changing the backing file
4335 int bdrv_change_backing_file(BlockDriverState *bs,
4336 const char *backing_file, const char *backing_fmt)
4338 BlockDriver *drv = bs->drv;
4339 int ret;
4341 if (!drv) {
4342 return -ENOMEDIUM;
4345 /* Backing file format doesn't make sense without a backing file */
4346 if (backing_fmt && !backing_file) {
4347 return -EINVAL;
4350 if (drv->bdrv_change_backing_file != NULL) {
4351 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
4352 } else {
4353 ret = -ENOTSUP;
4356 if (ret == 0) {
4357 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
4358 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
4359 pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file),
4360 backing_file ?: "");
4362 return ret;
4366 * Finds the image layer in the chain that has 'bs' as its backing file.
4368 * active is the current topmost image.
4370 * Returns NULL if bs is not found in active's image chain,
4371 * or if active == bs.
4373 * Returns the bottommost base image if bs == NULL.
4375 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
4376 BlockDriverState *bs)
4378 while (active && bs != backing_bs(active)) {
4379 active = backing_bs(active);
4382 return active;
4385 /* Given a BDS, searches for the base layer. */
4386 BlockDriverState *bdrv_find_base(BlockDriverState *bs)
4388 return bdrv_find_overlay(bs, NULL);
4392 * Return true if at least one of the backing links between @bs and
4393 * @base is frozen. @errp is set if that's the case.
4394 * @base must be reachable from @bs, or NULL.
4396 bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
4397 Error **errp)
4399 BlockDriverState *i;
4401 for (i = bs; i != base; i = backing_bs(i)) {
4402 if (i->backing && i->backing->frozen) {
4403 error_setg(errp, "Cannot change '%s' link from '%s' to '%s'",
4404 i->backing->name, i->node_name,
4405 backing_bs(i)->node_name);
4406 return true;
4410 return false;
4414 * Freeze all backing links between @bs and @base.
4415 * If any of the links is already frozen the operation is aborted and
4416 * none of the links are modified.
4417 * @base must be reachable from @bs, or NULL.
4418 * Returns 0 on success. On failure returns < 0 and sets @errp.
4420 int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
4421 Error **errp)
4423 BlockDriverState *i;
4425 if (bdrv_is_backing_chain_frozen(bs, base, errp)) {
4426 return -EPERM;
4429 for (i = bs; i != base; i = backing_bs(i)) {
4430 if (i->backing && backing_bs(i)->never_freeze) {
4431 error_setg(errp, "Cannot freeze '%s' link to '%s'",
4432 i->backing->name, backing_bs(i)->node_name);
4433 return -EPERM;
4437 for (i = bs; i != base; i = backing_bs(i)) {
4438 if (i->backing) {
4439 i->backing->frozen = true;
4443 return 0;
4447 * Unfreeze all backing links between @bs and @base. The caller must
4448 * ensure that all links are frozen before using this function.
4449 * @base must be reachable from @bs, or NULL.
4451 void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base)
4453 BlockDriverState *i;
4455 for (i = bs; i != base; i = backing_bs(i)) {
4456 if (i->backing) {
4457 assert(i->backing->frozen);
4458 i->backing->frozen = false;
4464 * Drops images above 'base' up to and including 'top', and sets the image
4465 * above 'top' to have base as its backing file.
4467 * Requires that the overlay to 'top' is opened r/w, so that the backing file
4468 * information in 'bs' can be properly updated.
4470 * E.g., this will convert the following chain:
4471 * bottom <- base <- intermediate <- top <- active
4473 * to
4475 * bottom <- base <- active
4477 * It is allowed for bottom==base, in which case it converts:
4479 * base <- intermediate <- top <- active
4481 * to
4483 * base <- active
4485 * If backing_file_str is non-NULL, it will be used when modifying top's
4486 * overlay image metadata.
4488 * Error conditions:
4489 * if active == top, that is considered an error
4492 int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
4493 const char *backing_file_str)
4495 BlockDriverState *explicit_top = top;
4496 bool update_inherits_from;
4497 BdrvChild *c, *next;
4498 Error *local_err = NULL;
4499 int ret = -EIO;
4501 bdrv_ref(top);
4503 if (!top->drv || !base->drv) {
4504 goto exit;
4507 /* Make sure that base is in the backing chain of top */
4508 if (!bdrv_chain_contains(top, base)) {
4509 goto exit;
4512 /* This function changes all links that point to top and makes
4513 * them point to base. Check that none of them is frozen. */
4514 QLIST_FOREACH(c, &top->parents, next_parent) {
4515 if (c->frozen) {
4516 goto exit;
4520 /* If 'base' recursively inherits from 'top' then we should set
4521 * base->inherits_from to top->inherits_from after 'top' and all
4522 * other intermediate nodes have been dropped.
4523 * If 'top' is an implicit node (e.g. "commit_top") we should skip
4524 * it because no one inherits from it. We use explicit_top for that. */
4525 while (explicit_top && explicit_top->implicit) {
4526 explicit_top = backing_bs(explicit_top);
4528 update_inherits_from = bdrv_inherits_from_recursive(base, explicit_top);
4530 /* success - we can delete the intermediate states, and link top->base */
4531 /* TODO Check graph modification op blockers (BLK_PERM_GRAPH_MOD) once
4532 * we've figured out how they should work. */
4533 if (!backing_file_str) {
4534 bdrv_refresh_filename(base);
4535 backing_file_str = base->filename;
4538 QLIST_FOREACH_SAFE(c, &top->parents, next_parent, next) {
4539 /* Check whether we are allowed to switch c from top to base */
4540 GSList *ignore_children = g_slist_prepend(NULL, c);
4541 ret = bdrv_check_update_perm(base, NULL, c->perm, c->shared_perm,
4542 ignore_children, NULL, &local_err);
4543 g_slist_free(ignore_children);
4544 if (ret < 0) {
4545 error_report_err(local_err);
4546 goto exit;
4549 /* If so, update the backing file path in the image file */
4550 if (c->role->update_filename) {
4551 ret = c->role->update_filename(c, base, backing_file_str,
4552 &local_err);
4553 if (ret < 0) {
4554 bdrv_abort_perm_update(base);
4555 error_report_err(local_err);
4556 goto exit;
4560 /* Do the actual switch in the in-memory graph.
4561 * Completes bdrv_check_update_perm() transaction internally. */
4562 bdrv_ref(base);
4563 bdrv_replace_child(c, base);
4564 bdrv_unref(top);
4567 if (update_inherits_from) {
4568 base->inherits_from = explicit_top->inherits_from;
4571 ret = 0;
4572 exit:
4573 bdrv_unref(top);
4574 return ret;
4578 * Length of a allocated file in bytes. Sparse files are counted by actual
4579 * allocated space. Return < 0 if error or unknown.
4581 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs)
4583 BlockDriver *drv = bs->drv;
4584 if (!drv) {
4585 return -ENOMEDIUM;
4587 if (drv->bdrv_get_allocated_file_size) {
4588 return drv->bdrv_get_allocated_file_size(bs);
4590 if (bs->file) {
4591 return bdrv_get_allocated_file_size(bs->file->bs);
4593 return -ENOTSUP;
4597 * bdrv_measure:
4598 * @drv: Format driver
4599 * @opts: Creation options for new image
4600 * @in_bs: Existing image containing data for new image (may be NULL)
4601 * @errp: Error object
4602 * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo())
4603 * or NULL on error
4605 * Calculate file size required to create a new image.
4607 * If @in_bs is given then space for allocated clusters and zero clusters
4608 * from that image are included in the calculation. If @opts contains a
4609 * backing file that is shared by @in_bs then backing clusters may be omitted
4610 * from the calculation.
4612 * If @in_bs is NULL then the calculation includes no allocated clusters
4613 * unless a preallocation option is given in @opts.
4615 * Note that @in_bs may use a different BlockDriver from @drv.
4617 * If an error occurs the @errp pointer is set.
4619 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
4620 BlockDriverState *in_bs, Error **errp)
4622 if (!drv->bdrv_measure) {
4623 error_setg(errp, "Block driver '%s' does not support size measurement",
4624 drv->format_name);
4625 return NULL;
4628 return drv->bdrv_measure(opts, in_bs, errp);
4632 * Return number of sectors on success, -errno on error.
4634 int64_t bdrv_nb_sectors(BlockDriverState *bs)
4636 BlockDriver *drv = bs->drv;
4638 if (!drv)
4639 return -ENOMEDIUM;
4641 if (drv->has_variable_length) {
4642 int ret = refresh_total_sectors(bs, bs->total_sectors);
4643 if (ret < 0) {
4644 return ret;
4647 return bs->total_sectors;
4651 * Return length in bytes on success, -errno on error.
4652 * The length is always a multiple of BDRV_SECTOR_SIZE.
4654 int64_t bdrv_getlength(BlockDriverState *bs)
4656 int64_t ret = bdrv_nb_sectors(bs);
4658 ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret;
4659 return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE;
4662 /* return 0 as number of sectors if no device present or error */
4663 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
4665 int64_t nb_sectors = bdrv_nb_sectors(bs);
4667 *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors;
4670 bool bdrv_is_sg(BlockDriverState *bs)
4672 return bs->sg;
4675 bool bdrv_is_encrypted(BlockDriverState *bs)
4677 if (bs->backing && bs->backing->bs->encrypted) {
4678 return true;
4680 return bs->encrypted;
4683 const char *bdrv_get_format_name(BlockDriverState *bs)
4685 return bs->drv ? bs->drv->format_name : NULL;
4688 static int qsort_strcmp(const void *a, const void *b)
4690 return strcmp(*(char *const *)a, *(char *const *)b);
4693 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
4694 void *opaque, bool read_only)
4696 BlockDriver *drv;
4697 int count = 0;
4698 int i;
4699 const char **formats = NULL;
4701 QLIST_FOREACH(drv, &bdrv_drivers, list) {
4702 if (drv->format_name) {
4703 bool found = false;
4704 int i = count;
4706 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, read_only)) {
4707 continue;
4710 while (formats && i && !found) {
4711 found = !strcmp(formats[--i], drv->format_name);
4714 if (!found) {
4715 formats = g_renew(const char *, formats, count + 1);
4716 formats[count++] = drv->format_name;
4721 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); i++) {
4722 const char *format_name = block_driver_modules[i].format_name;
4724 if (format_name) {
4725 bool found = false;
4726 int j = count;
4728 if (use_bdrv_whitelist &&
4729 !bdrv_format_is_whitelisted(format_name, read_only)) {
4730 continue;
4733 while (formats && j && !found) {
4734 found = !strcmp(formats[--j], format_name);
4737 if (!found) {
4738 formats = g_renew(const char *, formats, count + 1);
4739 formats[count++] = format_name;
4744 qsort(formats, count, sizeof(formats[0]), qsort_strcmp);
4746 for (i = 0; i < count; i++) {
4747 it(opaque, formats[i]);
4750 g_free(formats);
4753 /* This function is to find a node in the bs graph */
4754 BlockDriverState *bdrv_find_node(const char *node_name)
4756 BlockDriverState *bs;
4758 assert(node_name);
4760 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
4761 if (!strcmp(node_name, bs->node_name)) {
4762 return bs;
4765 return NULL;
4768 /* Put this QMP function here so it can access the static graph_bdrv_states. */
4769 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp)
4771 BlockDeviceInfoList *list, *entry;
4772 BlockDriverState *bs;
4774 list = NULL;
4775 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
4776 BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, errp);
4777 if (!info) {
4778 qapi_free_BlockDeviceInfoList(list);
4779 return NULL;
4781 entry = g_malloc0(sizeof(*entry));
4782 entry->value = info;
4783 entry->next = list;
4784 list = entry;
4787 return list;
4790 #define QAPI_LIST_ADD(list, element) do { \
4791 typeof(list) _tmp = g_new(typeof(*(list)), 1); \
4792 _tmp->value = (element); \
4793 _tmp->next = (list); \
4794 (list) = _tmp; \
4795 } while (0)
4797 typedef struct XDbgBlockGraphConstructor {
4798 XDbgBlockGraph *graph;
4799 GHashTable *graph_nodes;
4800 } XDbgBlockGraphConstructor;
4802 static XDbgBlockGraphConstructor *xdbg_graph_new(void)
4804 XDbgBlockGraphConstructor *gr = g_new(XDbgBlockGraphConstructor, 1);
4806 gr->graph = g_new0(XDbgBlockGraph, 1);
4807 gr->graph_nodes = g_hash_table_new(NULL, NULL);
4809 return gr;
4812 static XDbgBlockGraph *xdbg_graph_finalize(XDbgBlockGraphConstructor *gr)
4814 XDbgBlockGraph *graph = gr->graph;
4816 g_hash_table_destroy(gr->graph_nodes);
4817 g_free(gr);
4819 return graph;
4822 static uintptr_t xdbg_graph_node_num(XDbgBlockGraphConstructor *gr, void *node)
4824 uintptr_t ret = (uintptr_t)g_hash_table_lookup(gr->graph_nodes, node);
4826 if (ret != 0) {
4827 return ret;
4831 * Start counting from 1, not 0, because 0 interferes with not-found (NULL)
4832 * answer of g_hash_table_lookup.
4834 ret = g_hash_table_size(gr->graph_nodes) + 1;
4835 g_hash_table_insert(gr->graph_nodes, node, (void *)ret);
4837 return ret;
4840 static void xdbg_graph_add_node(XDbgBlockGraphConstructor *gr, void *node,
4841 XDbgBlockGraphNodeType type, const char *name)
4843 XDbgBlockGraphNode *n;
4845 n = g_new0(XDbgBlockGraphNode, 1);
4847 n->id = xdbg_graph_node_num(gr, node);
4848 n->type = type;
4849 n->name = g_strdup(name);
4851 QAPI_LIST_ADD(gr->graph->nodes, n);
4854 static void xdbg_graph_add_edge(XDbgBlockGraphConstructor *gr, void *parent,
4855 const BdrvChild *child)
4857 typedef struct {
4858 unsigned int flag;
4859 BlockPermission num;
4860 } PermissionMap;
4862 static const PermissionMap permissions[] = {
4863 { BLK_PERM_CONSISTENT_READ, BLOCK_PERMISSION_CONSISTENT_READ },
4864 { BLK_PERM_WRITE, BLOCK_PERMISSION_WRITE },
4865 { BLK_PERM_WRITE_UNCHANGED, BLOCK_PERMISSION_WRITE_UNCHANGED },
4866 { BLK_PERM_RESIZE, BLOCK_PERMISSION_RESIZE },
4867 { BLK_PERM_GRAPH_MOD, BLOCK_PERMISSION_GRAPH_MOD },
4868 { 0, 0 }
4870 const PermissionMap *p;
4871 XDbgBlockGraphEdge *edge;
4873 QEMU_BUILD_BUG_ON(1UL << (ARRAY_SIZE(permissions) - 1) != BLK_PERM_ALL + 1);
4875 edge = g_new0(XDbgBlockGraphEdge, 1);
4877 edge->parent = xdbg_graph_node_num(gr, parent);
4878 edge->child = xdbg_graph_node_num(gr, child->bs);
4879 edge->name = g_strdup(child->name);
4881 for (p = permissions; p->flag; p++) {
4882 if (p->flag & child->perm) {
4883 QAPI_LIST_ADD(edge->perm, p->num);
4885 if (p->flag & child->shared_perm) {
4886 QAPI_LIST_ADD(edge->shared_perm, p->num);
4890 QAPI_LIST_ADD(gr->graph->edges, edge);
4894 XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp)
4896 BlockBackend *blk;
4897 BlockJob *job;
4898 BlockDriverState *bs;
4899 BdrvChild *child;
4900 XDbgBlockGraphConstructor *gr = xdbg_graph_new();
4902 for (blk = blk_all_next(NULL); blk; blk = blk_all_next(blk)) {
4903 char *allocated_name = NULL;
4904 const char *name = blk_name(blk);
4906 if (!*name) {
4907 name = allocated_name = blk_get_attached_dev_id(blk);
4909 xdbg_graph_add_node(gr, blk, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND,
4910 name);
4911 g_free(allocated_name);
4912 if (blk_root(blk)) {
4913 xdbg_graph_add_edge(gr, blk, blk_root(blk));
4917 for (job = block_job_next(NULL); job; job = block_job_next(job)) {
4918 GSList *el;
4920 xdbg_graph_add_node(gr, job, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB,
4921 job->job.id);
4922 for (el = job->nodes; el; el = el->next) {
4923 xdbg_graph_add_edge(gr, job, (BdrvChild *)el->data);
4927 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
4928 xdbg_graph_add_node(gr, bs, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_DRIVER,
4929 bs->node_name);
4930 QLIST_FOREACH(child, &bs->children, next) {
4931 xdbg_graph_add_edge(gr, bs, child);
4935 return xdbg_graph_finalize(gr);
4938 BlockDriverState *bdrv_lookup_bs(const char *device,
4939 const char *node_name,
4940 Error **errp)
4942 BlockBackend *blk;
4943 BlockDriverState *bs;
4945 if (device) {
4946 blk = blk_by_name(device);
4948 if (blk) {
4949 bs = blk_bs(blk);
4950 if (!bs) {
4951 error_setg(errp, "Device '%s' has no medium", device);
4954 return bs;
4958 if (node_name) {
4959 bs = bdrv_find_node(node_name);
4961 if (bs) {
4962 return bs;
4966 error_setg(errp, "Cannot find device=%s nor node_name=%s",
4967 device ? device : "",
4968 node_name ? node_name : "");
4969 return NULL;
4972 /* If 'base' is in the same chain as 'top', return true. Otherwise,
4973 * return false. If either argument is NULL, return false. */
4974 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base)
4976 while (top && top != base) {
4977 top = backing_bs(top);
4980 return top != NULL;
4983 BlockDriverState *bdrv_next_node(BlockDriverState *bs)
4985 if (!bs) {
4986 return QTAILQ_FIRST(&graph_bdrv_states);
4988 return QTAILQ_NEXT(bs, node_list);
4991 BlockDriverState *bdrv_next_all_states(BlockDriverState *bs)
4993 if (!bs) {
4994 return QTAILQ_FIRST(&all_bdrv_states);
4996 return QTAILQ_NEXT(bs, bs_list);
4999 const char *bdrv_get_node_name(const BlockDriverState *bs)
5001 return bs->node_name;
5004 const char *bdrv_get_parent_name(const BlockDriverState *bs)
5006 BdrvChild *c;
5007 const char *name;
5009 /* If multiple parents have a name, just pick the first one. */
5010 QLIST_FOREACH(c, &bs->parents, next_parent) {
5011 if (c->role->get_name) {
5012 name = c->role->get_name(c);
5013 if (name && *name) {
5014 return name;
5019 return NULL;
5022 /* TODO check what callers really want: bs->node_name or blk_name() */
5023 const char *bdrv_get_device_name(const BlockDriverState *bs)
5025 return bdrv_get_parent_name(bs) ?: "";
5028 /* This can be used to identify nodes that might not have a device
5029 * name associated. Since node and device names live in the same
5030 * namespace, the result is unambiguous. The exception is if both are
5031 * absent, then this returns an empty (non-null) string. */
5032 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs)
5034 return bdrv_get_parent_name(bs) ?: bs->node_name;
5037 int bdrv_get_flags(BlockDriverState *bs)
5039 return bs->open_flags;
5042 int bdrv_has_zero_init_1(BlockDriverState *bs)
5044 return 1;
5047 int bdrv_has_zero_init(BlockDriverState *bs)
5049 if (!bs->drv) {
5050 return 0;
5053 /* If BS is a copy on write image, it is initialized to
5054 the contents of the base image, which may not be zeroes. */
5055 if (bs->backing) {
5056 return 0;
5058 if (bs->drv->bdrv_has_zero_init) {
5059 return bs->drv->bdrv_has_zero_init(bs);
5061 if (bs->file && bs->drv->is_filter) {
5062 return bdrv_has_zero_init(bs->file->bs);
5065 /* safe default */
5066 return 0;
5069 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs)
5071 BlockDriverInfo bdi;
5073 if (bs->backing) {
5074 return false;
5077 if (bdrv_get_info(bs, &bdi) == 0) {
5078 return bdi.unallocated_blocks_are_zero;
5081 return false;
5084 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
5086 if (!(bs->open_flags & BDRV_O_UNMAP)) {
5087 return false;
5090 return bs->supported_zero_flags & BDRV_REQ_MAY_UNMAP;
5093 void bdrv_get_backing_filename(BlockDriverState *bs,
5094 char *filename, int filename_size)
5096 pstrcpy(filename, filename_size, bs->backing_file);
5099 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
5101 BlockDriver *drv = bs->drv;
5102 /* if bs->drv == NULL, bs is closed, so there's nothing to do here */
5103 if (!drv) {
5104 return -ENOMEDIUM;
5106 if (!drv->bdrv_get_info) {
5107 if (bs->file && drv->is_filter) {
5108 return bdrv_get_info(bs->file->bs, bdi);
5110 return -ENOTSUP;
5112 memset(bdi, 0, sizeof(*bdi));
5113 return drv->bdrv_get_info(bs, bdi);
5116 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
5117 Error **errp)
5119 BlockDriver *drv = bs->drv;
5120 if (drv && drv->bdrv_get_specific_info) {
5121 return drv->bdrv_get_specific_info(bs, errp);
5123 return NULL;
5126 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event)
5128 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
5129 return;
5132 bs->drv->bdrv_debug_event(bs, event);
5135 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
5136 const char *tag)
5138 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) {
5139 bs = bs->file ? bs->file->bs : NULL;
5142 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) {
5143 return bs->drv->bdrv_debug_breakpoint(bs, event, tag);
5146 return -ENOTSUP;
5149 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag)
5151 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) {
5152 bs = bs->file ? bs->file->bs : NULL;
5155 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) {
5156 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag);
5159 return -ENOTSUP;
5162 int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
5164 while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) {
5165 bs = bs->file ? bs->file->bs : NULL;
5168 if (bs && bs->drv && bs->drv->bdrv_debug_resume) {
5169 return bs->drv->bdrv_debug_resume(bs, tag);
5172 return -ENOTSUP;
5175 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag)
5177 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) {
5178 bs = bs->file ? bs->file->bs : NULL;
5181 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) {
5182 return bs->drv->bdrv_debug_is_suspended(bs, tag);
5185 return false;
5188 /* backing_file can either be relative, or absolute, or a protocol. If it is
5189 * relative, it must be relative to the chain. So, passing in bs->filename
5190 * from a BDS as backing_file should not be done, as that may be relative to
5191 * the CWD rather than the chain. */
5192 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
5193 const char *backing_file)
5195 char *filename_full = NULL;
5196 char *backing_file_full = NULL;
5197 char *filename_tmp = NULL;
5198 int is_protocol = 0;
5199 BlockDriverState *curr_bs = NULL;
5200 BlockDriverState *retval = NULL;
5202 if (!bs || !bs->drv || !backing_file) {
5203 return NULL;
5206 filename_full = g_malloc(PATH_MAX);
5207 backing_file_full = g_malloc(PATH_MAX);
5209 is_protocol = path_has_protocol(backing_file);
5211 for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) {
5213 /* If either of the filename paths is actually a protocol, then
5214 * compare unmodified paths; otherwise make paths relative */
5215 if (is_protocol || path_has_protocol(curr_bs->backing_file)) {
5216 char *backing_file_full_ret;
5218 if (strcmp(backing_file, curr_bs->backing_file) == 0) {
5219 retval = curr_bs->backing->bs;
5220 break;
5222 /* Also check against the full backing filename for the image */
5223 backing_file_full_ret = bdrv_get_full_backing_filename(curr_bs,
5224 NULL);
5225 if (backing_file_full_ret) {
5226 bool equal = strcmp(backing_file, backing_file_full_ret) == 0;
5227 g_free(backing_file_full_ret);
5228 if (equal) {
5229 retval = curr_bs->backing->bs;
5230 break;
5233 } else {
5234 /* If not an absolute filename path, make it relative to the current
5235 * image's filename path */
5236 filename_tmp = bdrv_make_absolute_filename(curr_bs, backing_file,
5237 NULL);
5238 /* We are going to compare canonicalized absolute pathnames */
5239 if (!filename_tmp || !realpath(filename_tmp, filename_full)) {
5240 g_free(filename_tmp);
5241 continue;
5243 g_free(filename_tmp);
5245 /* We need to make sure the backing filename we are comparing against
5246 * is relative to the current image filename (or absolute) */
5247 filename_tmp = bdrv_get_full_backing_filename(curr_bs, NULL);
5248 if (!filename_tmp || !realpath(filename_tmp, backing_file_full)) {
5249 g_free(filename_tmp);
5250 continue;
5252 g_free(filename_tmp);
5254 if (strcmp(backing_file_full, filename_full) == 0) {
5255 retval = curr_bs->backing->bs;
5256 break;
5261 g_free(filename_full);
5262 g_free(backing_file_full);
5263 return retval;
5266 void bdrv_init(void)
5268 module_call_init(MODULE_INIT_BLOCK);
5271 void bdrv_init_with_whitelist(void)
5273 use_bdrv_whitelist = 1;
5274 bdrv_init();
5277 static void coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs,
5278 Error **errp)
5280 BdrvChild *child, *parent;
5281 uint64_t perm, shared_perm;
5282 Error *local_err = NULL;
5283 int ret;
5284 BdrvDirtyBitmap *bm;
5286 if (!bs->drv) {
5287 return;
5290 if (!(bs->open_flags & BDRV_O_INACTIVE)) {
5291 return;
5294 QLIST_FOREACH(child, &bs->children, next) {
5295 bdrv_co_invalidate_cache(child->bs, &local_err);
5296 if (local_err) {
5297 error_propagate(errp, local_err);
5298 return;
5303 * Update permissions, they may differ for inactive nodes.
5305 * Note that the required permissions of inactive images are always a
5306 * subset of the permissions required after activating the image. This
5307 * allows us to just get the permissions upfront without restricting
5308 * drv->bdrv_invalidate_cache().
5310 * It also means that in error cases, we don't have to try and revert to
5311 * the old permissions (which is an operation that could fail, too). We can
5312 * just keep the extended permissions for the next time that an activation
5313 * of the image is tried.
5315 bs->open_flags &= ~BDRV_O_INACTIVE;
5316 bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
5317 ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, NULL, &local_err);
5318 if (ret < 0) {
5319 bs->open_flags |= BDRV_O_INACTIVE;
5320 error_propagate(errp, local_err);
5321 return;
5323 bdrv_set_perm(bs, perm, shared_perm);
5325 if (bs->drv->bdrv_co_invalidate_cache) {
5326 bs->drv->bdrv_co_invalidate_cache(bs, &local_err);
5327 if (local_err) {
5328 bs->open_flags |= BDRV_O_INACTIVE;
5329 error_propagate(errp, local_err);
5330 return;
5334 for (bm = bdrv_dirty_bitmap_next(bs, NULL); bm;
5335 bm = bdrv_dirty_bitmap_next(bs, bm))
5337 bdrv_dirty_bitmap_set_migration(bm, false);
5340 ret = refresh_total_sectors(bs, bs->total_sectors);
5341 if (ret < 0) {
5342 bs->open_flags |= BDRV_O_INACTIVE;
5343 error_setg_errno(errp, -ret, "Could not refresh total sector count");
5344 return;
5347 QLIST_FOREACH(parent, &bs->parents, next_parent) {
5348 if (parent->role->activate) {
5349 parent->role->activate(parent, &local_err);
5350 if (local_err) {
5351 bs->open_flags |= BDRV_O_INACTIVE;
5352 error_propagate(errp, local_err);
5353 return;
5359 typedef struct InvalidateCacheCo {
5360 BlockDriverState *bs;
5361 Error **errp;
5362 bool done;
5363 } InvalidateCacheCo;
5365 static void coroutine_fn bdrv_invalidate_cache_co_entry(void *opaque)
5367 InvalidateCacheCo *ico = opaque;
5368 bdrv_co_invalidate_cache(ico->bs, ico->errp);
5369 ico->done = true;
5370 aio_wait_kick();
5373 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
5375 Coroutine *co;
5376 InvalidateCacheCo ico = {
5377 .bs = bs,
5378 .done = false,
5379 .errp = errp
5382 if (qemu_in_coroutine()) {
5383 /* Fast-path if already in coroutine context */
5384 bdrv_invalidate_cache_co_entry(&ico);
5385 } else {
5386 co = qemu_coroutine_create(bdrv_invalidate_cache_co_entry, &ico);
5387 bdrv_coroutine_enter(bs, co);
5388 BDRV_POLL_WHILE(bs, !ico.done);
5392 void bdrv_invalidate_cache_all(Error **errp)
5394 BlockDriverState *bs;
5395 Error *local_err = NULL;
5396 BdrvNextIterator it;
5398 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
5399 AioContext *aio_context = bdrv_get_aio_context(bs);
5401 aio_context_acquire(aio_context);
5402 bdrv_invalidate_cache(bs, &local_err);
5403 aio_context_release(aio_context);
5404 if (local_err) {
5405 error_propagate(errp, local_err);
5406 bdrv_next_cleanup(&it);
5407 return;
5412 static bool bdrv_has_bds_parent(BlockDriverState *bs, bool only_active)
5414 BdrvChild *parent;
5416 QLIST_FOREACH(parent, &bs->parents, next_parent) {
5417 if (parent->role->parent_is_bds) {
5418 BlockDriverState *parent_bs = parent->opaque;
5419 if (!only_active || !(parent_bs->open_flags & BDRV_O_INACTIVE)) {
5420 return true;
5425 return false;
5428 static int bdrv_inactivate_recurse(BlockDriverState *bs)
5430 BdrvChild *child, *parent;
5431 bool tighten_restrictions;
5432 uint64_t perm, shared_perm;
5433 int ret;
5435 if (!bs->drv) {
5436 return -ENOMEDIUM;
5439 /* Make sure that we don't inactivate a child before its parent.
5440 * It will be covered by recursion from the yet active parent. */
5441 if (bdrv_has_bds_parent(bs, true)) {
5442 return 0;
5445 assert(!(bs->open_flags & BDRV_O_INACTIVE));
5447 /* Inactivate this node */
5448 if (bs->drv->bdrv_inactivate) {
5449 ret = bs->drv->bdrv_inactivate(bs);
5450 if (ret < 0) {
5451 return ret;
5455 QLIST_FOREACH(parent, &bs->parents, next_parent) {
5456 if (parent->role->inactivate) {
5457 ret = parent->role->inactivate(parent);
5458 if (ret < 0) {
5459 return ret;
5464 bs->open_flags |= BDRV_O_INACTIVE;
5466 /* Update permissions, they may differ for inactive nodes */
5467 bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
5468 ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL,
5469 &tighten_restrictions, NULL);
5470 assert(tighten_restrictions == false);
5471 if (ret < 0) {
5472 /* We only tried to loosen restrictions, so errors are not fatal */
5473 bdrv_abort_perm_update(bs);
5474 } else {
5475 bdrv_set_perm(bs, perm, shared_perm);
5479 /* Recursively inactivate children */
5480 QLIST_FOREACH(child, &bs->children, next) {
5481 ret = bdrv_inactivate_recurse(child->bs);
5482 if (ret < 0) {
5483 return ret;
5487 return 0;
5490 int bdrv_inactivate_all(void)
5492 BlockDriverState *bs = NULL;
5493 BdrvNextIterator it;
5494 int ret = 0;
5495 GSList *aio_ctxs = NULL, *ctx;
5497 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
5498 AioContext *aio_context = bdrv_get_aio_context(bs);
5500 if (!g_slist_find(aio_ctxs, aio_context)) {
5501 aio_ctxs = g_slist_prepend(aio_ctxs, aio_context);
5502 aio_context_acquire(aio_context);
5506 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
5507 /* Nodes with BDS parents are covered by recursion from the last
5508 * parent that gets inactivated. Don't inactivate them a second
5509 * time if that has already happened. */
5510 if (bdrv_has_bds_parent(bs, false)) {
5511 continue;
5513 ret = bdrv_inactivate_recurse(bs);
5514 if (ret < 0) {
5515 bdrv_next_cleanup(&it);
5516 goto out;
5520 out:
5521 for (ctx = aio_ctxs; ctx != NULL; ctx = ctx->next) {
5522 AioContext *aio_context = ctx->data;
5523 aio_context_release(aio_context);
5525 g_slist_free(aio_ctxs);
5527 return ret;
5530 /**************************************************************/
5531 /* removable device support */
5534 * Return TRUE if the media is present
5536 bool bdrv_is_inserted(BlockDriverState *bs)
5538 BlockDriver *drv = bs->drv;
5539 BdrvChild *child;
5541 if (!drv) {
5542 return false;
5544 if (drv->bdrv_is_inserted) {
5545 return drv->bdrv_is_inserted(bs);
5547 QLIST_FOREACH(child, &bs->children, next) {
5548 if (!bdrv_is_inserted(child->bs)) {
5549 return false;
5552 return true;
5556 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
5558 void bdrv_eject(BlockDriverState *bs, bool eject_flag)
5560 BlockDriver *drv = bs->drv;
5562 if (drv && drv->bdrv_eject) {
5563 drv->bdrv_eject(bs, eject_flag);
5568 * Lock or unlock the media (if it is locked, the user won't be able
5569 * to eject it manually).
5571 void bdrv_lock_medium(BlockDriverState *bs, bool locked)
5573 BlockDriver *drv = bs->drv;
5575 trace_bdrv_lock_medium(bs, locked);
5577 if (drv && drv->bdrv_lock_medium) {
5578 drv->bdrv_lock_medium(bs, locked);
5582 /* Get a reference to bs */
5583 void bdrv_ref(BlockDriverState *bs)
5585 bs->refcnt++;
5588 /* Release a previously grabbed reference to bs.
5589 * If after releasing, reference count is zero, the BlockDriverState is
5590 * deleted. */
5591 void bdrv_unref(BlockDriverState *bs)
5593 if (!bs) {
5594 return;
5596 assert(bs->refcnt > 0);
5597 if (--bs->refcnt == 0) {
5598 bdrv_delete(bs);
5602 struct BdrvOpBlocker {
5603 Error *reason;
5604 QLIST_ENTRY(BdrvOpBlocker) list;
5607 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp)
5609 BdrvOpBlocker *blocker;
5610 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
5611 if (!QLIST_EMPTY(&bs->op_blockers[op])) {
5612 blocker = QLIST_FIRST(&bs->op_blockers[op]);
5613 error_propagate_prepend(errp, error_copy(blocker->reason),
5614 "Node '%s' is busy: ",
5615 bdrv_get_device_or_node_name(bs));
5616 return true;
5618 return false;
5621 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason)
5623 BdrvOpBlocker *blocker;
5624 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
5626 blocker = g_new0(BdrvOpBlocker, 1);
5627 blocker->reason = reason;
5628 QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list);
5631 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason)
5633 BdrvOpBlocker *blocker, *next;
5634 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
5635 QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) {
5636 if (blocker->reason == reason) {
5637 QLIST_REMOVE(blocker, list);
5638 g_free(blocker);
5643 void bdrv_op_block_all(BlockDriverState *bs, Error *reason)
5645 int i;
5646 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
5647 bdrv_op_block(bs, i, reason);
5651 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason)
5653 int i;
5654 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
5655 bdrv_op_unblock(bs, i, reason);
5659 bool bdrv_op_blocker_is_empty(BlockDriverState *bs)
5661 int i;
5663 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
5664 if (!QLIST_EMPTY(&bs->op_blockers[i])) {
5665 return false;
5668 return true;
5671 void bdrv_img_create(const char *filename, const char *fmt,
5672 const char *base_filename, const char *base_fmt,
5673 char *options, uint64_t img_size, int flags, bool quiet,
5674 Error **errp)
5676 QemuOptsList *create_opts = NULL;
5677 QemuOpts *opts = NULL;
5678 const char *backing_fmt, *backing_file;
5679 int64_t size;
5680 BlockDriver *drv, *proto_drv;
5681 Error *local_err = NULL;
5682 int ret = 0;
5684 /* Find driver and parse its options */
5685 drv = bdrv_find_format(fmt);
5686 if (!drv) {
5687 error_setg(errp, "Unknown file format '%s'", fmt);
5688 return;
5691 proto_drv = bdrv_find_protocol(filename, true, errp);
5692 if (!proto_drv) {
5693 return;
5696 if (!drv->create_opts) {
5697 error_setg(errp, "Format driver '%s' does not support image creation",
5698 drv->format_name);
5699 return;
5702 if (!proto_drv->create_opts) {
5703 error_setg(errp, "Protocol driver '%s' does not support image creation",
5704 proto_drv->format_name);
5705 return;
5708 create_opts = qemu_opts_append(create_opts, drv->create_opts);
5709 create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
5711 /* Create parameter list with default values */
5712 opts = qemu_opts_create(create_opts, NULL, 0, &error_abort);
5713 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, img_size, &error_abort);
5715 /* Parse -o options */
5716 if (options) {
5717 qemu_opts_do_parse(opts, options, NULL, &local_err);
5718 if (local_err) {
5719 goto out;
5723 if (base_filename) {
5724 qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename, &local_err);
5725 if (local_err) {
5726 error_setg(errp, "Backing file not supported for file format '%s'",
5727 fmt);
5728 goto out;
5732 if (base_fmt) {
5733 qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt, &local_err);
5734 if (local_err) {
5735 error_setg(errp, "Backing file format not supported for file "
5736 "format '%s'", fmt);
5737 goto out;
5741 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
5742 if (backing_file) {
5743 if (!strcmp(filename, backing_file)) {
5744 error_setg(errp, "Error: Trying to create an image with the "
5745 "same filename as the backing file");
5746 goto out;
5750 backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
5752 /* The size for the image must always be specified, unless we have a backing
5753 * file and we have not been forbidden from opening it. */
5754 size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, img_size);
5755 if (backing_file && !(flags & BDRV_O_NO_BACKING)) {
5756 BlockDriverState *bs;
5757 char *full_backing;
5758 int back_flags;
5759 QDict *backing_options = NULL;
5761 full_backing =
5762 bdrv_get_full_backing_filename_from_filename(filename, backing_file,
5763 &local_err);
5764 if (local_err) {
5765 goto out;
5767 assert(full_backing);
5769 /* backing files always opened read-only */
5770 back_flags = flags;
5771 back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
5773 backing_options = qdict_new();
5774 if (backing_fmt) {
5775 qdict_put_str(backing_options, "driver", backing_fmt);
5777 qdict_put_bool(backing_options, BDRV_OPT_FORCE_SHARE, true);
5779 bs = bdrv_open(full_backing, NULL, backing_options, back_flags,
5780 &local_err);
5781 g_free(full_backing);
5782 if (!bs && size != -1) {
5783 /* Couldn't open BS, but we have a size, so it's nonfatal */
5784 warn_reportf_err(local_err,
5785 "Could not verify backing image. "
5786 "This may become an error in future versions.\n");
5787 local_err = NULL;
5788 } else if (!bs) {
5789 /* Couldn't open bs, do not have size */
5790 error_append_hint(&local_err,
5791 "Could not open backing image to determine size.\n");
5792 goto out;
5793 } else {
5794 if (size == -1) {
5795 /* Opened BS, have no size */
5796 size = bdrv_getlength(bs);
5797 if (size < 0) {
5798 error_setg_errno(errp, -size, "Could not get size of '%s'",
5799 backing_file);
5800 bdrv_unref(bs);
5801 goto out;
5803 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort);
5805 bdrv_unref(bs);
5807 } /* (backing_file && !(flags & BDRV_O_NO_BACKING)) */
5809 if (size == -1) {
5810 error_setg(errp, "Image creation needs a size parameter");
5811 goto out;
5814 if (!quiet) {
5815 printf("Formatting '%s', fmt=%s ", filename, fmt);
5816 qemu_opts_print(opts, " ");
5817 puts("");
5820 ret = bdrv_create(drv, filename, opts, &local_err);
5822 if (ret == -EFBIG) {
5823 /* This is generally a better message than whatever the driver would
5824 * deliver (especially because of the cluster_size_hint), since that
5825 * is most probably not much different from "image too large". */
5826 const char *cluster_size_hint = "";
5827 if (qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 0)) {
5828 cluster_size_hint = " (try using a larger cluster size)";
5830 error_setg(errp, "The image size is too large for file format '%s'"
5831 "%s", fmt, cluster_size_hint);
5832 error_free(local_err);
5833 local_err = NULL;
5836 out:
5837 qemu_opts_del(opts);
5838 qemu_opts_free(create_opts);
5839 error_propagate(errp, local_err);
5842 AioContext *bdrv_get_aio_context(BlockDriverState *bs)
5844 return bs ? bs->aio_context : qemu_get_aio_context();
5847 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co)
5849 aio_co_enter(bdrv_get_aio_context(bs), co);
5852 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban)
5854 QLIST_REMOVE(ban, list);
5855 g_free(ban);
5858 static void bdrv_detach_aio_context(BlockDriverState *bs)
5860 BdrvAioNotifier *baf, *baf_tmp;
5862 assert(!bs->walking_aio_notifiers);
5863 bs->walking_aio_notifiers = true;
5864 QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) {
5865 if (baf->deleted) {
5866 bdrv_do_remove_aio_context_notifier(baf);
5867 } else {
5868 baf->detach_aio_context(baf->opaque);
5871 /* Never mind iterating again to check for ->deleted. bdrv_close() will
5872 * remove remaining aio notifiers if we aren't called again.
5874 bs->walking_aio_notifiers = false;
5876 if (bs->drv && bs->drv->bdrv_detach_aio_context) {
5877 bs->drv->bdrv_detach_aio_context(bs);
5880 if (bs->quiesce_counter) {
5881 aio_enable_external(bs->aio_context);
5883 bs->aio_context = NULL;
5886 static void bdrv_attach_aio_context(BlockDriverState *bs,
5887 AioContext *new_context)
5889 BdrvAioNotifier *ban, *ban_tmp;
5891 if (bs->quiesce_counter) {
5892 aio_disable_external(new_context);
5895 bs->aio_context = new_context;
5897 if (bs->drv && bs->drv->bdrv_attach_aio_context) {
5898 bs->drv->bdrv_attach_aio_context(bs, new_context);
5901 assert(!bs->walking_aio_notifiers);
5902 bs->walking_aio_notifiers = true;
5903 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_tmp) {
5904 if (ban->deleted) {
5905 bdrv_do_remove_aio_context_notifier(ban);
5906 } else {
5907 ban->attached_aio_context(new_context, ban->opaque);
5910 bs->walking_aio_notifiers = false;
5914 * Changes the AioContext used for fd handlers, timers, and BHs by this
5915 * BlockDriverState and all its children and parents.
5917 * Must be called from the main AioContext.
5919 * The caller must own the AioContext lock for the old AioContext of bs, but it
5920 * must not own the AioContext lock for new_context (unless new_context is the
5921 * same as the current context of bs).
5923 * @ignore will accumulate all visited BdrvChild object. The caller is
5924 * responsible for freeing the list afterwards.
5926 void bdrv_set_aio_context_ignore(BlockDriverState *bs,
5927 AioContext *new_context, GSList **ignore)
5929 AioContext *old_context = bdrv_get_aio_context(bs);
5930 BdrvChild *child;
5932 g_assert(qemu_get_current_aio_context() == qemu_get_aio_context());
5934 if (old_context == new_context) {
5935 return;
5938 bdrv_drained_begin(bs);
5940 QLIST_FOREACH(child, &bs->children, next) {
5941 if (g_slist_find(*ignore, child)) {
5942 continue;
5944 *ignore = g_slist_prepend(*ignore, child);
5945 bdrv_set_aio_context_ignore(child->bs, new_context, ignore);
5947 QLIST_FOREACH(child, &bs->parents, next_parent) {
5948 if (g_slist_find(*ignore, child)) {
5949 continue;
5951 assert(child->role->set_aio_ctx);
5952 *ignore = g_slist_prepend(*ignore, child);
5953 child->role->set_aio_ctx(child, new_context, ignore);
5956 bdrv_detach_aio_context(bs);
5958 /* Acquire the new context, if necessary */
5959 if (qemu_get_aio_context() != new_context) {
5960 aio_context_acquire(new_context);
5963 bdrv_attach_aio_context(bs, new_context);
5966 * If this function was recursively called from
5967 * bdrv_set_aio_context_ignore(), there may be nodes in the
5968 * subtree that have not yet been moved to the new AioContext.
5969 * Release the old one so bdrv_drained_end() can poll them.
5971 if (qemu_get_aio_context() != old_context) {
5972 aio_context_release(old_context);
5975 bdrv_drained_end(bs);
5977 if (qemu_get_aio_context() != old_context) {
5978 aio_context_acquire(old_context);
5980 if (qemu_get_aio_context() != new_context) {
5981 aio_context_release(new_context);
5985 static bool bdrv_parent_can_set_aio_context(BdrvChild *c, AioContext *ctx,
5986 GSList **ignore, Error **errp)
5988 if (g_slist_find(*ignore, c)) {
5989 return true;
5991 *ignore = g_slist_prepend(*ignore, c);
5993 /* A BdrvChildRole that doesn't handle AioContext changes cannot
5994 * tolerate any AioContext changes */
5995 if (!c->role->can_set_aio_ctx) {
5996 char *user = bdrv_child_user_desc(c);
5997 error_setg(errp, "Changing iothreads is not supported by %s", user);
5998 g_free(user);
5999 return false;
6001 if (!c->role->can_set_aio_ctx(c, ctx, ignore, errp)) {
6002 assert(!errp || *errp);
6003 return false;
6005 return true;
6008 bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx,
6009 GSList **ignore, Error **errp)
6011 if (g_slist_find(*ignore, c)) {
6012 return true;
6014 *ignore = g_slist_prepend(*ignore, c);
6015 return bdrv_can_set_aio_context(c->bs, ctx, ignore, errp);
6018 /* @ignore will accumulate all visited BdrvChild object. The caller is
6019 * responsible for freeing the list afterwards. */
6020 bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx,
6021 GSList **ignore, Error **errp)
6023 BdrvChild *c;
6025 if (bdrv_get_aio_context(bs) == ctx) {
6026 return true;
6029 QLIST_FOREACH(c, &bs->parents, next_parent) {
6030 if (!bdrv_parent_can_set_aio_context(c, ctx, ignore, errp)) {
6031 return false;
6034 QLIST_FOREACH(c, &bs->children, next) {
6035 if (!bdrv_child_can_set_aio_context(c, ctx, ignore, errp)) {
6036 return false;
6040 return true;
6043 int bdrv_child_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
6044 BdrvChild *ignore_child, Error **errp)
6046 GSList *ignore;
6047 bool ret;
6049 ignore = ignore_child ? g_slist_prepend(NULL, ignore_child) : NULL;
6050 ret = bdrv_can_set_aio_context(bs, ctx, &ignore, errp);
6051 g_slist_free(ignore);
6053 if (!ret) {
6054 return -EPERM;
6057 ignore = ignore_child ? g_slist_prepend(NULL, ignore_child) : NULL;
6058 bdrv_set_aio_context_ignore(bs, ctx, &ignore);
6059 g_slist_free(ignore);
6061 return 0;
6064 int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
6065 Error **errp)
6067 return bdrv_child_try_set_aio_context(bs, ctx, NULL, errp);
6070 void bdrv_add_aio_context_notifier(BlockDriverState *bs,
6071 void (*attached_aio_context)(AioContext *new_context, void *opaque),
6072 void (*detach_aio_context)(void *opaque), void *opaque)
6074 BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1);
6075 *ban = (BdrvAioNotifier){
6076 .attached_aio_context = attached_aio_context,
6077 .detach_aio_context = detach_aio_context,
6078 .opaque = opaque
6081 QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list);
6084 void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
6085 void (*attached_aio_context)(AioContext *,
6086 void *),
6087 void (*detach_aio_context)(void *),
6088 void *opaque)
6090 BdrvAioNotifier *ban, *ban_next;
6092 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
6093 if (ban->attached_aio_context == attached_aio_context &&
6094 ban->detach_aio_context == detach_aio_context &&
6095 ban->opaque == opaque &&
6096 ban->deleted == false)
6098 if (bs->walking_aio_notifiers) {
6099 ban->deleted = true;
6100 } else {
6101 bdrv_do_remove_aio_context_notifier(ban);
6103 return;
6107 abort();
6110 int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts,
6111 BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
6112 Error **errp)
6114 if (!bs->drv) {
6115 error_setg(errp, "Node is ejected");
6116 return -ENOMEDIUM;
6118 if (!bs->drv->bdrv_amend_options) {
6119 error_setg(errp, "Block driver '%s' does not support option amendment",
6120 bs->drv->format_name);
6121 return -ENOTSUP;
6123 return bs->drv->bdrv_amend_options(bs, opts, status_cb, cb_opaque, errp);
6126 /* This function will be called by the bdrv_recurse_is_first_non_filter method
6127 * of block filter and by bdrv_is_first_non_filter.
6128 * It is used to test if the given bs is the candidate or recurse more in the
6129 * node graph.
6131 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
6132 BlockDriverState *candidate)
6134 /* return false if basic checks fails */
6135 if (!bs || !bs->drv) {
6136 return false;
6139 /* the code reached a non block filter driver -> check if the bs is
6140 * the same as the candidate. It's the recursion termination condition.
6142 if (!bs->drv->is_filter) {
6143 return bs == candidate;
6145 /* Down this path the driver is a block filter driver */
6147 /* If the block filter recursion method is defined use it to recurse down
6148 * the node graph.
6150 if (bs->drv->bdrv_recurse_is_first_non_filter) {
6151 return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate);
6154 /* the driver is a block filter but don't allow to recurse -> return false
6156 return false;
6159 /* This function checks if the candidate is the first non filter bs down it's
6160 * bs chain. Since we don't have pointers to parents it explore all bs chains
6161 * from the top. Some filters can choose not to pass down the recursion.
6163 bool bdrv_is_first_non_filter(BlockDriverState *candidate)
6165 BlockDriverState *bs;
6166 BdrvNextIterator it;
6168 /* walk down the bs forest recursively */
6169 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
6170 bool perm;
6172 /* try to recurse in this top level bs */
6173 perm = bdrv_recurse_is_first_non_filter(bs, candidate);
6175 /* candidate is the first non filter */
6176 if (perm) {
6177 bdrv_next_cleanup(&it);
6178 return true;
6182 return false;
6185 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
6186 const char *node_name, Error **errp)
6188 BlockDriverState *to_replace_bs = bdrv_find_node(node_name);
6189 AioContext *aio_context;
6191 if (!to_replace_bs) {
6192 error_setg(errp, "Node name '%s' not found", node_name);
6193 return NULL;
6196 aio_context = bdrv_get_aio_context(to_replace_bs);
6197 aio_context_acquire(aio_context);
6199 if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) {
6200 to_replace_bs = NULL;
6201 goto out;
6204 /* We don't want arbitrary node of the BDS chain to be replaced only the top
6205 * most non filter in order to prevent data corruption.
6206 * Another benefit is that this tests exclude backing files which are
6207 * blocked by the backing blockers.
6209 if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) {
6210 error_setg(errp, "Only top most non filter can be replaced");
6211 to_replace_bs = NULL;
6212 goto out;
6215 out:
6216 aio_context_release(aio_context);
6217 return to_replace_bs;
6221 * Iterates through the list of runtime option keys that are said to
6222 * be "strong" for a BDS. An option is called "strong" if it changes
6223 * a BDS's data. For example, the null block driver's "size" and
6224 * "read-zeroes" options are strong, but its "latency-ns" option is
6225 * not.
6227 * If a key returned by this function ends with a dot, all options
6228 * starting with that prefix are strong.
6230 static const char *const *strong_options(BlockDriverState *bs,
6231 const char *const *curopt)
6233 static const char *const global_options[] = {
6234 "driver", "filename", NULL
6237 if (!curopt) {
6238 return &global_options[0];
6241 curopt++;
6242 if (curopt == &global_options[ARRAY_SIZE(global_options) - 1] && bs->drv) {
6243 curopt = bs->drv->strong_runtime_opts;
6246 return (curopt && *curopt) ? curopt : NULL;
6250 * Copies all strong runtime options from bs->options to the given
6251 * QDict. The set of strong option keys is determined by invoking
6252 * strong_options().
6254 * Returns true iff any strong option was present in bs->options (and
6255 * thus copied to the target QDict) with the exception of "filename"
6256 * and "driver". The caller is expected to use this value to decide
6257 * whether the existence of strong options prevents the generation of
6258 * a plain filename.
6260 static bool append_strong_runtime_options(QDict *d, BlockDriverState *bs)
6262 bool found_any = false;
6263 const char *const *option_name = NULL;
6265 if (!bs->drv) {
6266 return false;
6269 while ((option_name = strong_options(bs, option_name))) {
6270 bool option_given = false;
6272 assert(strlen(*option_name) > 0);
6273 if ((*option_name)[strlen(*option_name) - 1] != '.') {
6274 QObject *entry = qdict_get(bs->options, *option_name);
6275 if (!entry) {
6276 continue;
6279 qdict_put_obj(d, *option_name, qobject_ref(entry));
6280 option_given = true;
6281 } else {
6282 const QDictEntry *entry;
6283 for (entry = qdict_first(bs->options); entry;
6284 entry = qdict_next(bs->options, entry))
6286 if (strstart(qdict_entry_key(entry), *option_name, NULL)) {
6287 qdict_put_obj(d, qdict_entry_key(entry),
6288 qobject_ref(qdict_entry_value(entry)));
6289 option_given = true;
6294 /* While "driver" and "filename" need to be included in a JSON filename,
6295 * their existence does not prohibit generation of a plain filename. */
6296 if (!found_any && option_given &&
6297 strcmp(*option_name, "driver") && strcmp(*option_name, "filename"))
6299 found_any = true;
6303 if (!qdict_haskey(d, "driver")) {
6304 /* Drivers created with bdrv_new_open_driver() may not have a
6305 * @driver option. Add it here. */
6306 qdict_put_str(d, "driver", bs->drv->format_name);
6309 return found_any;
6312 /* Note: This function may return false positives; it may return true
6313 * even if opening the backing file specified by bs's image header
6314 * would result in exactly bs->backing. */
6315 static bool bdrv_backing_overridden(BlockDriverState *bs)
6317 if (bs->backing) {
6318 return strcmp(bs->auto_backing_file,
6319 bs->backing->bs->filename);
6320 } else {
6321 /* No backing BDS, so if the image header reports any backing
6322 * file, it must have been suppressed */
6323 return bs->auto_backing_file[0] != '\0';
6327 /* Updates the following BDS fields:
6328 * - exact_filename: A filename which may be used for opening a block device
6329 * which (mostly) equals the given BDS (even without any
6330 * other options; so reading and writing must return the same
6331 * results, but caching etc. may be different)
6332 * - full_open_options: Options which, when given when opening a block device
6333 * (without a filename), result in a BDS (mostly)
6334 * equalling the given one
6335 * - filename: If exact_filename is set, it is copied here. Otherwise,
6336 * full_open_options is converted to a JSON object, prefixed with
6337 * "json:" (for use through the JSON pseudo protocol) and put here.
6339 void bdrv_refresh_filename(BlockDriverState *bs)
6341 BlockDriver *drv = bs->drv;
6342 BdrvChild *child;
6343 QDict *opts;
6344 bool backing_overridden;
6345 bool generate_json_filename; /* Whether our default implementation should
6346 fill exact_filename (false) or not (true) */
6348 if (!drv) {
6349 return;
6352 /* This BDS's file name may depend on any of its children's file names, so
6353 * refresh those first */
6354 QLIST_FOREACH(child, &bs->children, next) {
6355 bdrv_refresh_filename(child->bs);
6358 if (bs->implicit) {
6359 /* For implicit nodes, just copy everything from the single child */
6360 child = QLIST_FIRST(&bs->children);
6361 assert(QLIST_NEXT(child, next) == NULL);
6363 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
6364 child->bs->exact_filename);
6365 pstrcpy(bs->filename, sizeof(bs->filename), child->bs->filename);
6367 bs->full_open_options = qobject_ref(child->bs->full_open_options);
6369 return;
6372 backing_overridden = bdrv_backing_overridden(bs);
6374 if (bs->open_flags & BDRV_O_NO_IO) {
6375 /* Without I/O, the backing file does not change anything.
6376 * Therefore, in such a case (primarily qemu-img), we can
6377 * pretend the backing file has not been overridden even if
6378 * it technically has been. */
6379 backing_overridden = false;
6382 /* Gather the options QDict */
6383 opts = qdict_new();
6384 generate_json_filename = append_strong_runtime_options(opts, bs);
6385 generate_json_filename |= backing_overridden;
6387 if (drv->bdrv_gather_child_options) {
6388 /* Some block drivers may not want to present all of their children's
6389 * options, or name them differently from BdrvChild.name */
6390 drv->bdrv_gather_child_options(bs, opts, backing_overridden);
6391 } else {
6392 QLIST_FOREACH(child, &bs->children, next) {
6393 if (child->role == &child_backing && !backing_overridden) {
6394 /* We can skip the backing BDS if it has not been overridden */
6395 continue;
6398 qdict_put(opts, child->name,
6399 qobject_ref(child->bs->full_open_options));
6402 if (backing_overridden && !bs->backing) {
6403 /* Force no backing file */
6404 qdict_put_null(opts, "backing");
6408 qobject_unref(bs->full_open_options);
6409 bs->full_open_options = opts;
6411 if (drv->bdrv_refresh_filename) {
6412 /* Obsolete information is of no use here, so drop the old file name
6413 * information before refreshing it */
6414 bs->exact_filename[0] = '\0';
6416 drv->bdrv_refresh_filename(bs);
6417 } else if (bs->file) {
6418 /* Try to reconstruct valid information from the underlying file */
6420 bs->exact_filename[0] = '\0';
6423 * We can use the underlying file's filename if:
6424 * - it has a filename,
6425 * - the file is a protocol BDS, and
6426 * - opening that file (as this BDS's format) will automatically create
6427 * the BDS tree we have right now, that is:
6428 * - the user did not significantly change this BDS's behavior with
6429 * some explicit (strong) options
6430 * - no non-file child of this BDS has been overridden by the user
6431 * Both of these conditions are represented by generate_json_filename.
6433 if (bs->file->bs->exact_filename[0] &&
6434 bs->file->bs->drv->bdrv_file_open &&
6435 !generate_json_filename)
6437 strcpy(bs->exact_filename, bs->file->bs->exact_filename);
6441 if (bs->exact_filename[0]) {
6442 pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename);
6443 } else {
6444 QString *json = qobject_to_json(QOBJECT(bs->full_open_options));
6445 snprintf(bs->filename, sizeof(bs->filename), "json:%s",
6446 qstring_get_str(json));
6447 qobject_unref(json);
6451 char *bdrv_dirname(BlockDriverState *bs, Error **errp)
6453 BlockDriver *drv = bs->drv;
6455 if (!drv) {
6456 error_setg(errp, "Node '%s' is ejected", bs->node_name);
6457 return NULL;
6460 if (drv->bdrv_dirname) {
6461 return drv->bdrv_dirname(bs, errp);
6464 if (bs->file) {
6465 return bdrv_dirname(bs->file->bs, errp);
6468 bdrv_refresh_filename(bs);
6469 if (bs->exact_filename[0] != '\0') {
6470 return path_combine(bs->exact_filename, "");
6473 error_setg(errp, "Cannot generate a base directory for %s nodes",
6474 drv->format_name);
6475 return NULL;
6479 * Hot add/remove a BDS's child. So the user can take a child offline when
6480 * it is broken and take a new child online
6482 void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs,
6483 Error **errp)
6486 if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) {
6487 error_setg(errp, "The node %s does not support adding a child",
6488 bdrv_get_device_or_node_name(parent_bs));
6489 return;
6492 if (!QLIST_EMPTY(&child_bs->parents)) {
6493 error_setg(errp, "The node %s already has a parent",
6494 child_bs->node_name);
6495 return;
6498 parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp);
6501 void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp)
6503 BdrvChild *tmp;
6505 if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) {
6506 error_setg(errp, "The node %s does not support removing a child",
6507 bdrv_get_device_or_node_name(parent_bs));
6508 return;
6511 QLIST_FOREACH(tmp, &parent_bs->children, next) {
6512 if (tmp == child) {
6513 break;
6517 if (!tmp) {
6518 error_setg(errp, "The node %s does not have a child named %s",
6519 bdrv_get_device_or_node_name(parent_bs),
6520 bdrv_get_device_or_node_name(child->bs));
6521 return;
6524 parent_bs->drv->bdrv_del_child(parent_bs, child, errp);
6527 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
6528 uint32_t granularity, Error **errp)
6530 BlockDriver *drv = bs->drv;
6532 if (!drv) {
6533 error_setg_errno(errp, ENOMEDIUM,
6534 "Can't store persistent bitmaps to %s",
6535 bdrv_get_device_or_node_name(bs));
6536 return false;
6539 if (!drv->bdrv_can_store_new_dirty_bitmap) {
6540 error_setg_errno(errp, ENOTSUP,
6541 "Can't store persistent bitmaps to %s",
6542 bdrv_get_device_or_node_name(bs));
6543 return false;
6546 return drv->bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp);