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
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 "block/module_block.h"
33 #include "qemu/main-loop.h"
34 #include "qemu/module.h"
35 #include "qapi/error.h"
36 #include "qapi/qmp/qdict.h"
37 #include "qapi/qmp/qjson.h"
38 #include "qapi/qmp/qnull.h"
39 #include "qapi/qmp/qstring.h"
40 #include "qapi/qobject-output-visitor.h"
41 #include "qapi/qapi-visit-block-core.h"
42 #include "sysemu/block-backend.h"
43 #include "sysemu/sysemu.h"
44 #include "qemu/notify.h"
45 #include "qemu/option.h"
46 #include "qemu/coroutine.h"
47 #include "block/qapi.h"
48 #include "qemu/timer.h"
49 #include "qemu/cutils.h"
53 #include <sys/ioctl.h>
54 #include <sys/queue.h>
64 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
66 static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states =
67 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states);
69 static QTAILQ_HEAD(, BlockDriverState) all_bdrv_states =
70 QTAILQ_HEAD_INITIALIZER(all_bdrv_states);
72 static QLIST_HEAD(, BlockDriver) bdrv_drivers =
73 QLIST_HEAD_INITIALIZER(bdrv_drivers);
75 static BlockDriverState *bdrv_open_inherit(const char *filename,
76 const char *reference,
77 QDict *options, int flags,
78 BlockDriverState *parent,
79 const BdrvChildClass *child_class,
80 BdrvChildRole child_role,
83 /* If non-zero, use only whitelisted block drivers */
84 static int use_bdrv_whitelist;
87 static int is_windows_drive_prefix(const char *filename)
89 return (((filename[0] >= 'a' && filename[0] <= 'z') ||
90 (filename[0] >= 'A' && filename[0] <= 'Z')) &&
94 int is_windows_drive(const char *filename)
96 if (is_windows_drive_prefix(filename) &&
99 if (strstart(filename, "\\\\.\\", NULL) ||
100 strstart(filename, "//./", NULL))
106 size_t bdrv_opt_mem_align(BlockDriverState *bs)
108 if (!bs || !bs->drv) {
109 /* page size or 4k (hdd sector size) should be on the safe side */
110 return MAX(4096, qemu_real_host_page_size);
113 return bs->bl.opt_mem_alignment;
116 size_t bdrv_min_mem_align(BlockDriverState *bs)
118 if (!bs || !bs->drv) {
119 /* page size or 4k (hdd sector size) should be on the safe side */
120 return MAX(4096, qemu_real_host_page_size);
123 return bs->bl.min_mem_alignment;
126 /* check if the path starts with "<protocol>:" */
127 int path_has_protocol(const char *path)
132 if (is_windows_drive(path) ||
133 is_windows_drive_prefix(path)) {
136 p = path + strcspn(path, ":/\\");
138 p = path + strcspn(path, ":/");
144 int path_is_absolute(const char *path)
147 /* specific case for names like: "\\.\d:" */
148 if (is_windows_drive(path) || is_windows_drive_prefix(path)) {
151 return (*path == '/' || *path == '\\');
153 return (*path == '/');
157 /* if filename is absolute, just return its duplicate. Otherwise, build a
158 path to it by considering it is relative to base_path. URL are
160 char *path_combine(const char *base_path, const char *filename)
162 const char *protocol_stripped = NULL;
167 if (path_is_absolute(filename)) {
168 return g_strdup(filename);
171 if (path_has_protocol(base_path)) {
172 protocol_stripped = strchr(base_path, ':');
173 if (protocol_stripped) {
177 p = protocol_stripped ?: base_path;
179 p1 = strrchr(base_path, '/');
183 p2 = strrchr(base_path, '\\');
184 if (!p1 || p2 > p1) {
199 result = g_malloc(len + strlen(filename) + 1);
200 memcpy(result, base_path, len);
201 strcpy(result + len, filename);
207 * Helper function for bdrv_parse_filename() implementations to remove optional
208 * protocol prefixes (especially "file:") from a filename and for putting the
209 * stripped filename into the options QDict if there is such a prefix.
211 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix,
214 if (strstart(filename, prefix, &filename)) {
215 /* Stripping the explicit protocol prefix may result in a protocol
216 * prefix being (wrongly) detected (if the filename contains a colon) */
217 if (path_has_protocol(filename)) {
218 QString *fat_filename;
220 /* This means there is some colon before the first slash; therefore,
221 * this cannot be an absolute path */
222 assert(!path_is_absolute(filename));
224 /* And we can thus fix the protocol detection issue by prefixing it
226 fat_filename = qstring_from_str("./");
227 qstring_append(fat_filename, filename);
229 assert(!path_has_protocol(qstring_get_str(fat_filename)));
231 qdict_put(options, "filename", fat_filename);
233 /* If no protocol prefix was detected, we can use the shortened
235 qdict_put_str(options, "filename", filename);
241 /* Returns whether the image file is opened as read-only. Note that this can
242 * return false and writing to the image file is still not possible because the
243 * image is inactivated. */
244 bool bdrv_is_read_only(BlockDriverState *bs)
246 return bs->read_only;
249 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
250 bool ignore_allow_rdw, Error **errp)
252 /* Do not set read_only if copy_on_read is enabled */
253 if (bs->copy_on_read && read_only) {
254 error_setg(errp, "Can't set node '%s' to r/o with copy-on-read enabled",
255 bdrv_get_device_or_node_name(bs));
259 /* Do not clear read_only if it is prohibited */
260 if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR) &&
263 error_setg(errp, "Node '%s' is read only",
264 bdrv_get_device_or_node_name(bs));
272 * Called by a driver that can only provide a read-only image.
274 * Returns 0 if the node is already read-only or it could switch the node to
275 * read-only because BDRV_O_AUTO_RDONLY is set.
277 * Returns -EACCES if the node is read-write and BDRV_O_AUTO_RDONLY is not set
278 * or bdrv_can_set_read_only() forbids making the node read-only. If @errmsg
279 * is not NULL, it is used as the error message for the Error object.
281 int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
286 if (!(bs->open_flags & BDRV_O_RDWR)) {
289 if (!(bs->open_flags & BDRV_O_AUTO_RDONLY)) {
293 ret = bdrv_can_set_read_only(bs, true, false, NULL);
298 bs->read_only = true;
299 bs->open_flags &= ~BDRV_O_RDWR;
304 error_setg(errp, "%s", errmsg ?: "Image is read-only");
309 * If @backing is empty, this function returns NULL without setting
310 * @errp. In all other cases, NULL will only be returned with @errp
313 * Therefore, a return value of NULL without @errp set means that
314 * there is no backing file; if @errp is set, there is one but its
315 * absolute filename cannot be generated.
317 char *bdrv_get_full_backing_filename_from_filename(const char *backed,
321 if (backing[0] == '\0') {
323 } else if (path_has_protocol(backing) || path_is_absolute(backing)) {
324 return g_strdup(backing);
325 } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) {
326 error_setg(errp, "Cannot use relative backing file names for '%s'",
330 return path_combine(backed, backing);
335 * If @filename is empty or NULL, this function returns NULL without
336 * setting @errp. In all other cases, NULL will only be returned with
339 static char *bdrv_make_absolute_filename(BlockDriverState *relative_to,
340 const char *filename, Error **errp)
342 char *dir, *full_name;
344 if (!filename || filename[0] == '\0') {
346 } else if (path_has_protocol(filename) || path_is_absolute(filename)) {
347 return g_strdup(filename);
350 dir = bdrv_dirname(relative_to, errp);
355 full_name = g_strconcat(dir, filename, NULL);
360 char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp)
362 return bdrv_make_absolute_filename(bs, bs->backing_file, errp);
365 void bdrv_register(BlockDriver *bdrv)
367 assert(bdrv->format_name);
368 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list);
371 BlockDriverState *bdrv_new(void)
373 BlockDriverState *bs;
376 bs = g_new0(BlockDriverState, 1);
377 QLIST_INIT(&bs->dirty_bitmaps);
378 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
379 QLIST_INIT(&bs->op_blockers[i]);
381 notifier_with_return_list_init(&bs->before_write_notifiers);
382 qemu_co_mutex_init(&bs->reqs_lock);
383 qemu_mutex_init(&bs->dirty_bitmap_mutex);
385 bs->aio_context = qemu_get_aio_context();
387 qemu_co_queue_init(&bs->flush_queue);
389 for (i = 0; i < bdrv_drain_all_count; i++) {
390 bdrv_drained_begin(bs);
393 QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list);
398 static BlockDriver *bdrv_do_find_format(const char *format_name)
402 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
403 if (!strcmp(drv1->format_name, format_name)) {
411 BlockDriver *bdrv_find_format(const char *format_name)
416 drv1 = bdrv_do_find_format(format_name);
421 /* The driver isn't registered, maybe we need to load a module */
422 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
423 if (!strcmp(block_driver_modules[i].format_name, format_name)) {
424 block_module_load_one(block_driver_modules[i].library_name);
429 return bdrv_do_find_format(format_name);
432 static int bdrv_format_is_whitelisted(const char *format_name, bool read_only)
434 static const char *whitelist_rw[] = {
435 CONFIG_BDRV_RW_WHITELIST
438 static const char *whitelist_ro[] = {
439 CONFIG_BDRV_RO_WHITELIST
444 if (!whitelist_rw[0] && !whitelist_ro[0]) {
445 return 1; /* no whitelist, anything goes */
448 for (p = whitelist_rw; *p; p++) {
449 if (!strcmp(format_name, *p)) {
454 for (p = whitelist_ro; *p; p++) {
455 if (!strcmp(format_name, *p)) {
463 int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
465 return bdrv_format_is_whitelisted(drv->format_name, read_only);
468 bool bdrv_uses_whitelist(void)
470 return use_bdrv_whitelist;
473 typedef struct CreateCo {
481 static void coroutine_fn bdrv_create_co_entry(void *opaque)
483 Error *local_err = NULL;
486 CreateCo *cco = opaque;
489 ret = cco->drv->bdrv_co_create_opts(cco->drv,
490 cco->filename, cco->opts, &local_err);
491 error_propagate(&cco->err, local_err);
495 int bdrv_create(BlockDriver *drv, const char* filename,
496 QemuOpts *opts, Error **errp)
503 .filename = g_strdup(filename),
509 if (!drv->bdrv_co_create_opts) {
510 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name);
515 if (qemu_in_coroutine()) {
516 /* Fast-path if already in coroutine context */
517 bdrv_create_co_entry(&cco);
519 co = qemu_coroutine_create(bdrv_create_co_entry, &cco);
520 qemu_coroutine_enter(co);
521 while (cco.ret == NOT_DONE) {
522 aio_poll(qemu_get_aio_context(), true);
529 error_propagate(errp, cco.err);
531 error_setg_errno(errp, -ret, "Could not create image");
536 g_free(cco.filename);
541 * Helper function for bdrv_create_file_fallback(): Resize @blk to at
542 * least the given @minimum_size.
544 * On success, return @blk's actual length.
545 * Otherwise, return -errno.
547 static int64_t create_file_fallback_truncate(BlockBackend *blk,
548 int64_t minimum_size, Error **errp)
550 Error *local_err = NULL;
554 ret = blk_truncate(blk, minimum_size, false, PREALLOC_MODE_OFF, 0,
556 if (ret < 0 && ret != -ENOTSUP) {
557 error_propagate(errp, local_err);
561 size = blk_getlength(blk);
563 error_free(local_err);
564 error_setg_errno(errp, -size,
565 "Failed to inquire the new image file's length");
569 if (size < minimum_size) {
570 /* Need to grow the image, but we failed to do that */
571 error_propagate(errp, local_err);
575 error_free(local_err);
582 * Helper function for bdrv_create_file_fallback(): Zero the first
583 * sector to remove any potentially pre-existing image header.
585 static int create_file_fallback_zero_first_sector(BlockBackend *blk,
586 int64_t current_size,
589 int64_t bytes_to_clear;
592 bytes_to_clear = MIN(current_size, BDRV_SECTOR_SIZE);
593 if (bytes_to_clear) {
594 ret = blk_pwrite_zeroes(blk, 0, bytes_to_clear, BDRV_REQ_MAY_UNMAP);
596 error_setg_errno(errp, -ret,
597 "Failed to clear the new image's first sector");
606 * Simple implementation of bdrv_co_create_opts for protocol drivers
607 * which only support creation via opening a file
608 * (usually existing raw storage device)
610 int coroutine_fn bdrv_co_create_opts_simple(BlockDriver *drv,
611 const char *filename,
619 PreallocMode prealloc;
620 Error *local_err = NULL;
623 size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
624 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
625 prealloc = qapi_enum_parse(&PreallocMode_lookup, buf,
626 PREALLOC_MODE_OFF, &local_err);
629 error_propagate(errp, local_err);
633 if (prealloc != PREALLOC_MODE_OFF) {
634 error_setg(errp, "Unsupported preallocation mode '%s'",
635 PreallocMode_str(prealloc));
639 options = qdict_new();
640 qdict_put_str(options, "driver", drv->format_name);
642 blk = blk_new_open(filename, NULL, options,
643 BDRV_O_RDWR | BDRV_O_RESIZE, errp);
645 error_prepend(errp, "Protocol driver '%s' does not support image "
646 "creation, and opening the image failed: ",
651 size = create_file_fallback_truncate(blk, size, errp);
657 ret = create_file_fallback_zero_first_sector(blk, size, errp);
668 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
672 drv = bdrv_find_protocol(filename, true, errp);
677 return bdrv_create(drv, filename, opts, errp);
680 int coroutine_fn bdrv_co_delete_file(BlockDriverState *bs, Error **errp)
682 Error *local_err = NULL;
688 error_setg(errp, "Block node '%s' is not opened", bs->filename);
692 if (!bs->drv->bdrv_co_delete_file) {
693 error_setg(errp, "Driver '%s' does not support image deletion",
694 bs->drv->format_name);
698 ret = bs->drv->bdrv_co_delete_file(bs, &local_err);
700 error_propagate(errp, local_err);
707 * Try to get @bs's logical and physical block size.
708 * On success, store them in @bsz struct and return 0.
709 * On failure return -errno.
710 * @bs must not be empty.
712 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
714 BlockDriver *drv = bs->drv;
715 BlockDriverState *filtered = bdrv_filter_bs(bs);
717 if (drv && drv->bdrv_probe_blocksizes) {
718 return drv->bdrv_probe_blocksizes(bs, bsz);
719 } else if (filtered) {
720 return bdrv_probe_blocksizes(filtered, bsz);
727 * Try to get @bs's geometry (cyls, heads, sectors).
728 * On success, store them in @geo struct and return 0.
729 * On failure return -errno.
730 * @bs must not be empty.
732 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
734 BlockDriver *drv = bs->drv;
735 BlockDriverState *filtered = bdrv_filter_bs(bs);
737 if (drv && drv->bdrv_probe_geometry) {
738 return drv->bdrv_probe_geometry(bs, geo);
739 } else if (filtered) {
740 return bdrv_probe_geometry(filtered, geo);
747 * Create a uniquely-named empty temporary file.
748 * Return 0 upon success, otherwise a negative errno value.
750 int get_tmp_filename(char *filename, int size)
753 char temp_dir[MAX_PATH];
754 /* GetTempFileName requires that its output buffer (4th param)
755 have length MAX_PATH or greater. */
756 assert(size >= MAX_PATH);
757 return (GetTempPath(MAX_PATH, temp_dir)
758 && GetTempFileName(temp_dir, "qem", 0, filename)
759 ? 0 : -GetLastError());
763 tmpdir = getenv("TMPDIR");
767 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) {
770 fd = mkstemp(filename);
774 if (close(fd) != 0) {
783 * Detect host devices. By convention, /dev/cdrom[N] is always
784 * recognized as a host CDROM.
786 static BlockDriver *find_hdev_driver(const char *filename)
788 int score_max = 0, score;
789 BlockDriver *drv = NULL, *d;
791 QLIST_FOREACH(d, &bdrv_drivers, list) {
792 if (d->bdrv_probe_device) {
793 score = d->bdrv_probe_device(filename);
794 if (score > score_max) {
804 static BlockDriver *bdrv_do_find_protocol(const char *protocol)
808 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
809 if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) {
817 BlockDriver *bdrv_find_protocol(const char *filename,
818 bool allow_protocol_prefix,
827 /* TODO Drivers without bdrv_file_open must be specified explicitly */
830 * XXX(hch): we really should not let host device detection
831 * override an explicit protocol specification, but moving this
832 * later breaks access to device names with colons in them.
833 * Thanks to the brain-dead persistent naming schemes on udev-
834 * based Linux systems those actually are quite common.
836 drv1 = find_hdev_driver(filename);
841 if (!path_has_protocol(filename) || !allow_protocol_prefix) {
845 p = strchr(filename, ':');
848 if (len > sizeof(protocol) - 1)
849 len = sizeof(protocol) - 1;
850 memcpy(protocol, filename, len);
851 protocol[len] = '\0';
853 drv1 = bdrv_do_find_protocol(protocol);
858 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
859 if (block_driver_modules[i].protocol_name &&
860 !strcmp(block_driver_modules[i].protocol_name, protocol)) {
861 block_module_load_one(block_driver_modules[i].library_name);
866 drv1 = bdrv_do_find_protocol(protocol);
868 error_setg(errp, "Unknown protocol '%s'", protocol);
874 * Guess image format by probing its contents.
875 * This is not a good idea when your image is raw (CVE-2008-2004), but
876 * we do it anyway for backward compatibility.
878 * @buf contains the image's first @buf_size bytes.
879 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
880 * but can be smaller if the image file is smaller)
881 * @filename is its filename.
883 * For all block drivers, call the bdrv_probe() method to get its
885 * Return the first block driver with the highest probing score.
887 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
888 const char *filename)
890 int score_max = 0, score;
891 BlockDriver *drv = NULL, *d;
893 QLIST_FOREACH(d, &bdrv_drivers, list) {
895 score = d->bdrv_probe(buf, buf_size, filename);
896 if (score > score_max) {
906 static int find_image_format(BlockBackend *file, const char *filename,
907 BlockDriver **pdrv, Error **errp)
910 uint8_t buf[BLOCK_PROBE_BUF_SIZE];
913 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
914 if (blk_is_sg(file) || !blk_is_inserted(file) || blk_getlength(file) == 0) {
919 ret = blk_pread(file, 0, buf, sizeof(buf));
921 error_setg_errno(errp, -ret, "Could not read image for determining its "
927 drv = bdrv_probe_all(buf, ret, filename);
929 error_setg(errp, "Could not determine image format: No compatible "
938 * Set the current 'total_sectors' value
939 * Return 0 on success, -errno on error.
941 int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
943 BlockDriver *drv = bs->drv;
949 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
953 /* query actual device if possible, otherwise just trust the hint */
954 if (drv->bdrv_getlength) {
955 int64_t length = drv->bdrv_getlength(bs);
959 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE);
962 bs->total_sectors = hint;
967 * Combines a QDict of new block driver @options with any missing options taken
968 * from @old_options, so that leaving out an option defaults to its old value.
970 static void bdrv_join_options(BlockDriverState *bs, QDict *options,
973 if (bs->drv && bs->drv->bdrv_join_options) {
974 bs->drv->bdrv_join_options(options, old_options);
976 qdict_join(options, old_options, false);
980 static BlockdevDetectZeroesOptions bdrv_parse_detect_zeroes(QemuOpts *opts,
984 Error *local_err = NULL;
985 char *value = qemu_opt_get_del(opts, "detect-zeroes");
986 BlockdevDetectZeroesOptions detect_zeroes =
987 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup, value,
988 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF, &local_err);
991 error_propagate(errp, local_err);
992 return detect_zeroes;
995 if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
996 !(open_flags & BDRV_O_UNMAP))
998 error_setg(errp, "setting detect-zeroes to unmap is not allowed "
999 "without setting discard operation to unmap");
1002 return detect_zeroes;
1006 * Set open flags for aio engine
1008 * Return 0 on success, -1 if the engine specified is invalid
1010 int bdrv_parse_aio(const char *mode, int *flags)
1012 if (!strcmp(mode, "threads")) {
1013 /* do nothing, default */
1014 } else if (!strcmp(mode, "native")) {
1015 *flags |= BDRV_O_NATIVE_AIO;
1016 #ifdef CONFIG_LINUX_IO_URING
1017 } else if (!strcmp(mode, "io_uring")) {
1018 *flags |= BDRV_O_IO_URING;
1028 * Set open flags for a given discard mode
1030 * Return 0 on success, -1 if the discard mode was invalid.
1032 int bdrv_parse_discard_flags(const char *mode, int *flags)
1034 *flags &= ~BDRV_O_UNMAP;
1036 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) {
1038 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) {
1039 *flags |= BDRV_O_UNMAP;
1048 * Set open flags for a given cache mode
1050 * Return 0 on success, -1 if the cache mode was invalid.
1052 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough)
1054 *flags &= ~BDRV_O_CACHE_MASK;
1056 if (!strcmp(mode, "off") || !strcmp(mode, "none")) {
1057 *writethrough = false;
1058 *flags |= BDRV_O_NOCACHE;
1059 } else if (!strcmp(mode, "directsync")) {
1060 *writethrough = true;
1061 *flags |= BDRV_O_NOCACHE;
1062 } else if (!strcmp(mode, "writeback")) {
1063 *writethrough = false;
1064 } else if (!strcmp(mode, "unsafe")) {
1065 *writethrough = false;
1066 *flags |= BDRV_O_NO_FLUSH;
1067 } else if (!strcmp(mode, "writethrough")) {
1068 *writethrough = true;
1076 static char *bdrv_child_get_parent_desc(BdrvChild *c)
1078 BlockDriverState *parent = c->opaque;
1079 return g_strdup(bdrv_get_device_or_node_name(parent));
1082 static void bdrv_child_cb_drained_begin(BdrvChild *child)
1084 BlockDriverState *bs = child->opaque;
1085 bdrv_do_drained_begin_quiesce(bs, NULL, false);
1088 static bool bdrv_child_cb_drained_poll(BdrvChild *child)
1090 BlockDriverState *bs = child->opaque;
1091 return bdrv_drain_poll(bs, false, NULL, false);
1094 static void bdrv_child_cb_drained_end(BdrvChild *child,
1095 int *drained_end_counter)
1097 BlockDriverState *bs = child->opaque;
1098 bdrv_drained_end_no_poll(bs, drained_end_counter);
1101 static int bdrv_child_cb_inactivate(BdrvChild *child)
1103 BlockDriverState *bs = child->opaque;
1104 assert(bs->open_flags & BDRV_O_INACTIVE);
1108 static bool bdrv_child_cb_can_set_aio_ctx(BdrvChild *child, AioContext *ctx,
1109 GSList **ignore, Error **errp)
1111 BlockDriverState *bs = child->opaque;
1112 return bdrv_can_set_aio_context(bs, ctx, ignore, errp);
1115 static void bdrv_child_cb_set_aio_ctx(BdrvChild *child, AioContext *ctx,
1118 BlockDriverState *bs = child->opaque;
1119 return bdrv_set_aio_context_ignore(bs, ctx, ignore);
1123 * Returns the options and flags that a temporary snapshot should get, based on
1124 * the originally requested flags (the originally requested image will have
1125 * flags like a backing file)
1127 static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
1128 int parent_flags, QDict *parent_options)
1130 *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY;
1132 /* For temporary files, unconditional cache=unsafe is fine */
1133 qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off");
1134 qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
1136 /* Copy the read-only and discard options from the parent */
1137 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
1138 qdict_copy_default(child_options, parent_options, BDRV_OPT_DISCARD);
1140 /* aio=native doesn't work for cache.direct=off, so disable it for the
1141 * temporary snapshot */
1142 *child_flags &= ~BDRV_O_NATIVE_AIO;
1145 static void bdrv_backing_attach(BdrvChild *c)
1147 BlockDriverState *parent = c->opaque;
1148 BlockDriverState *backing_hd = c->bs;
1150 assert(!parent->backing_blocker);
1151 error_setg(&parent->backing_blocker,
1152 "node is used as backing hd of '%s'",
1153 bdrv_get_device_or_node_name(parent));
1155 bdrv_refresh_filename(backing_hd);
1157 parent->open_flags &= ~BDRV_O_NO_BACKING;
1159 bdrv_op_block_all(backing_hd, parent->backing_blocker);
1160 /* Otherwise we won't be able to commit or stream */
1161 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,
1162 parent->backing_blocker);
1163 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_STREAM,
1164 parent->backing_blocker);
1166 * We do backup in 3 ways:
1168 * The target bs is new opened, and the source is top BDS
1169 * 2. blockdev backup
1170 * Both the source and the target are top BDSes.
1171 * 3. internal backup(used for block replication)
1172 * Both the source and the target are backing file
1174 * In case 1 and 2, neither the source nor the target is the backing file.
1175 * In case 3, we will block the top BDS, so there is only one block job
1176 * for the top BDS and its backing chain.
1178 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_SOURCE,
1179 parent->backing_blocker);
1180 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_TARGET,
1181 parent->backing_blocker);
1184 static void bdrv_backing_detach(BdrvChild *c)
1186 BlockDriverState *parent = c->opaque;
1188 assert(parent->backing_blocker);
1189 bdrv_op_unblock_all(c->bs, parent->backing_blocker);
1190 error_free(parent->backing_blocker);
1191 parent->backing_blocker = NULL;
1194 static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
1195 const char *filename, Error **errp)
1197 BlockDriverState *parent = c->opaque;
1198 bool read_only = bdrv_is_read_only(parent);
1202 ret = bdrv_reopen_set_read_only(parent, false, errp);
1208 ret = bdrv_change_backing_file(parent, filename,
1209 base->drv ? base->drv->format_name : "",
1212 error_setg_errno(errp, -ret, "Could not update backing file link");
1216 bdrv_reopen_set_read_only(parent, true, NULL);
1223 * Returns the options and flags that a generic child of a BDS should
1224 * get, based on the given options and flags for the parent BDS.
1226 static void bdrv_inherited_options(BdrvChildRole role, bool parent_is_format,
1227 int *child_flags, QDict *child_options,
1228 int parent_flags, QDict *parent_options)
1230 int flags = parent_flags;
1233 * First, decide whether to set, clear, or leave BDRV_O_PROTOCOL.
1234 * Generally, the question to answer is: Should this child be
1235 * format-probed by default?
1239 * Pure and non-filtered data children of non-format nodes should
1240 * be probed by default (even when the node itself has BDRV_O_PROTOCOL
1241 * set). This only affects a very limited set of drivers (namely
1242 * quorum and blkverify when this comment was written).
1243 * Force-clear BDRV_O_PROTOCOL then.
1245 if (!parent_is_format &&
1246 (role & BDRV_CHILD_DATA) &&
1247 !(role & (BDRV_CHILD_METADATA | BDRV_CHILD_FILTERED)))
1249 flags &= ~BDRV_O_PROTOCOL;
1253 * All children of format nodes (except for COW children) and all
1254 * metadata children in general should never be format-probed.
1255 * Force-set BDRV_O_PROTOCOL then.
1257 if ((parent_is_format && !(role & BDRV_CHILD_COW)) ||
1258 (role & BDRV_CHILD_METADATA))
1260 flags |= BDRV_O_PROTOCOL;
1264 * If the cache mode isn't explicitly set, inherit direct and no-flush from
1267 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
1268 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
1269 qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
1271 if (role & BDRV_CHILD_COW) {
1272 /* backing files are opened read-only by default */
1273 qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on");
1274 qdict_set_default_str(child_options, BDRV_OPT_AUTO_READ_ONLY, "off");
1276 /* Inherit the read-only option from the parent if it's not set */
1277 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
1278 qdict_copy_default(child_options, parent_options,
1279 BDRV_OPT_AUTO_READ_ONLY);
1283 * bdrv_co_pdiscard() respects unmap policy for the parent, so we
1284 * can default to enable it on lower layers regardless of the
1287 qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap");
1289 /* Clear flags that only apply to the top layer */
1290 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ);
1292 if (role & BDRV_CHILD_METADATA) {
1293 flags &= ~BDRV_O_NO_IO;
1295 if (role & BDRV_CHILD_COW) {
1296 flags &= ~BDRV_O_TEMPORARY;
1299 *child_flags = flags;
1302 static void bdrv_child_cb_attach(BdrvChild *child)
1304 BlockDriverState *bs = child->opaque;
1306 if (child->role & BDRV_CHILD_COW) {
1307 bdrv_backing_attach(child);
1310 bdrv_apply_subtree_drain(child, bs);
1313 static void bdrv_child_cb_detach(BdrvChild *child)
1315 BlockDriverState *bs = child->opaque;
1317 if (child->role & BDRV_CHILD_COW) {
1318 bdrv_backing_detach(child);
1321 bdrv_unapply_subtree_drain(child, bs);
1324 static int bdrv_child_cb_update_filename(BdrvChild *c, BlockDriverState *base,
1325 const char *filename, Error **errp)
1327 if (c->role & BDRV_CHILD_COW) {
1328 return bdrv_backing_update_filename(c, base, filename, errp);
1333 const BdrvChildClass child_of_bds = {
1334 .parent_is_bds = true,
1335 .get_parent_desc = bdrv_child_get_parent_desc,
1336 .inherit_options = bdrv_inherited_options,
1337 .drained_begin = bdrv_child_cb_drained_begin,
1338 .drained_poll = bdrv_child_cb_drained_poll,
1339 .drained_end = bdrv_child_cb_drained_end,
1340 .attach = bdrv_child_cb_attach,
1341 .detach = bdrv_child_cb_detach,
1342 .inactivate = bdrv_child_cb_inactivate,
1343 .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx,
1344 .set_aio_ctx = bdrv_child_cb_set_aio_ctx,
1345 .update_filename = bdrv_child_cb_update_filename,
1348 static int bdrv_open_flags(BlockDriverState *bs, int flags)
1350 int open_flags = flags;
1353 * Clear flags that are internal to the block layer before opening the
1356 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL);
1361 static void update_flags_from_options(int *flags, QemuOpts *opts)
1363 *flags &= ~(BDRV_O_CACHE_MASK | BDRV_O_RDWR | BDRV_O_AUTO_RDONLY);
1365 if (qemu_opt_get_bool_del(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
1366 *flags |= BDRV_O_NO_FLUSH;
1369 if (qemu_opt_get_bool_del(opts, BDRV_OPT_CACHE_DIRECT, false)) {
1370 *flags |= BDRV_O_NOCACHE;
1373 if (!qemu_opt_get_bool_del(opts, BDRV_OPT_READ_ONLY, false)) {
1374 *flags |= BDRV_O_RDWR;
1377 if (qemu_opt_get_bool_del(opts, BDRV_OPT_AUTO_READ_ONLY, false)) {
1378 *flags |= BDRV_O_AUTO_RDONLY;
1382 static void update_options_from_flags(QDict *options, int flags)
1384 if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) {
1385 qdict_put_bool(options, BDRV_OPT_CACHE_DIRECT, flags & BDRV_O_NOCACHE);
1387 if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) {
1388 qdict_put_bool(options, BDRV_OPT_CACHE_NO_FLUSH,
1389 flags & BDRV_O_NO_FLUSH);
1391 if (!qdict_haskey(options, BDRV_OPT_READ_ONLY)) {
1392 qdict_put_bool(options, BDRV_OPT_READ_ONLY, !(flags & BDRV_O_RDWR));
1394 if (!qdict_haskey(options, BDRV_OPT_AUTO_READ_ONLY)) {
1395 qdict_put_bool(options, BDRV_OPT_AUTO_READ_ONLY,
1396 flags & BDRV_O_AUTO_RDONLY);
1400 static void bdrv_assign_node_name(BlockDriverState *bs,
1401 const char *node_name,
1404 char *gen_node_name = NULL;
1407 node_name = gen_node_name = id_generate(ID_BLOCK);
1408 } else if (!id_wellformed(node_name)) {
1410 * Check for empty string or invalid characters, but not if it is
1411 * generated (generated names use characters not available to the user)
1413 error_setg(errp, "Invalid node name");
1417 /* takes care of avoiding namespaces collisions */
1418 if (blk_by_name(node_name)) {
1419 error_setg(errp, "node-name=%s is conflicting with a device id",
1424 /* takes care of avoiding duplicates node names */
1425 if (bdrv_find_node(node_name)) {
1426 error_setg(errp, "Duplicate node name");
1430 /* Make sure that the node name isn't truncated */
1431 if (strlen(node_name) >= sizeof(bs->node_name)) {
1432 error_setg(errp, "Node name too long");
1436 /* copy node name into the bs and insert it into the graph list */
1437 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
1438 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
1440 g_free(gen_node_name);
1443 static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv,
1444 const char *node_name, QDict *options,
1445 int open_flags, Error **errp)
1447 Error *local_err = NULL;
1450 bdrv_assign_node_name(bs, node_name, &local_err);
1452 error_propagate(errp, local_err);
1457 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
1458 bs->opaque = g_malloc0(drv->instance_size);
1460 if (drv->bdrv_file_open) {
1461 assert(!drv->bdrv_needs_filename || bs->filename[0]);
1462 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err);
1463 } else if (drv->bdrv_open) {
1464 ret = drv->bdrv_open(bs, options, open_flags, &local_err);
1471 error_propagate(errp, local_err);
1472 } else if (bs->filename[0]) {
1473 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename);
1475 error_setg_errno(errp, -ret, "Could not open image");
1480 ret = refresh_total_sectors(bs, bs->total_sectors);
1482 error_setg_errno(errp, -ret, "Could not refresh total sector count");
1486 bdrv_refresh_limits(bs, &local_err);
1488 error_propagate(errp, local_err);
1492 assert(bdrv_opt_mem_align(bs) != 0);
1493 assert(bdrv_min_mem_align(bs) != 0);
1494 assert(is_power_of_2(bs->bl.request_alignment));
1496 for (i = 0; i < bs->quiesce_counter; i++) {
1497 if (drv->bdrv_co_drain_begin) {
1498 drv->bdrv_co_drain_begin(bs);
1505 if (bs->file != NULL) {
1506 bdrv_unref_child(bs, bs->file);
1514 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
1515 int flags, Error **errp)
1517 BlockDriverState *bs;
1521 bs->open_flags = flags;
1522 bs->explicit_options = qdict_new();
1523 bs->options = qdict_new();
1526 update_options_from_flags(bs->options, flags);
1528 ret = bdrv_open_driver(bs, drv, node_name, bs->options, flags, errp);
1530 qobject_unref(bs->explicit_options);
1531 bs->explicit_options = NULL;
1532 qobject_unref(bs->options);
1541 QemuOptsList bdrv_runtime_opts = {
1542 .name = "bdrv_common",
1543 .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head),
1546 .name = "node-name",
1547 .type = QEMU_OPT_STRING,
1548 .help = "Node name of the block device node",
1552 .type = QEMU_OPT_STRING,
1553 .help = "Block driver to use for the node",
1556 .name = BDRV_OPT_CACHE_DIRECT,
1557 .type = QEMU_OPT_BOOL,
1558 .help = "Bypass software writeback cache on the host",
1561 .name = BDRV_OPT_CACHE_NO_FLUSH,
1562 .type = QEMU_OPT_BOOL,
1563 .help = "Ignore flush requests",
1566 .name = BDRV_OPT_READ_ONLY,
1567 .type = QEMU_OPT_BOOL,
1568 .help = "Node is opened in read-only mode",
1571 .name = BDRV_OPT_AUTO_READ_ONLY,
1572 .type = QEMU_OPT_BOOL,
1573 .help = "Node can become read-only if opening read-write fails",
1576 .name = "detect-zeroes",
1577 .type = QEMU_OPT_STRING,
1578 .help = "try to optimize zero writes (off, on, unmap)",
1581 .name = BDRV_OPT_DISCARD,
1582 .type = QEMU_OPT_STRING,
1583 .help = "discard operation (ignore/off, unmap/on)",
1586 .name = BDRV_OPT_FORCE_SHARE,
1587 .type = QEMU_OPT_BOOL,
1588 .help = "always accept other writers (default: off)",
1590 { /* end of list */ }
1594 QemuOptsList bdrv_create_opts_simple = {
1595 .name = "simple-create-opts",
1596 .head = QTAILQ_HEAD_INITIALIZER(bdrv_create_opts_simple.head),
1599 .name = BLOCK_OPT_SIZE,
1600 .type = QEMU_OPT_SIZE,
1601 .help = "Virtual disk size"
1604 .name = BLOCK_OPT_PREALLOC,
1605 .type = QEMU_OPT_STRING,
1606 .help = "Preallocation mode (allowed values: off)"
1608 { /* end of list */ }
1613 * Common part for opening disk images and files
1615 * Removes all processed options from *options.
1617 static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file,
1618 QDict *options, Error **errp)
1620 int ret, open_flags;
1621 const char *filename;
1622 const char *driver_name = NULL;
1623 const char *node_name = NULL;
1624 const char *discard;
1627 Error *local_err = NULL;
1629 assert(bs->file == NULL);
1630 assert(options != NULL && bs->options != options);
1632 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
1633 if (!qemu_opts_absorb_qdict(opts, options, errp)) {
1638 update_flags_from_options(&bs->open_flags, opts);
1640 driver_name = qemu_opt_get(opts, "driver");
1641 drv = bdrv_find_format(driver_name);
1642 assert(drv != NULL);
1644 bs->force_share = qemu_opt_get_bool(opts, BDRV_OPT_FORCE_SHARE, false);
1646 if (bs->force_share && (bs->open_flags & BDRV_O_RDWR)) {
1648 BDRV_OPT_FORCE_SHARE
1649 "=on can only be used with read-only images");
1655 bdrv_refresh_filename(blk_bs(file));
1656 filename = blk_bs(file)->filename;
1659 * Caution: while qdict_get_try_str() is fine, getting
1660 * non-string types would require more care. When @options
1661 * come from -blockdev or blockdev_add, its members are typed
1662 * according to the QAPI schema, but when they come from
1663 * -drive, they're all QString.
1665 filename = qdict_get_try_str(options, "filename");
1668 if (drv->bdrv_needs_filename && (!filename || !filename[0])) {
1669 error_setg(errp, "The '%s' block driver requires a file name",
1675 trace_bdrv_open_common(bs, filename ?: "", bs->open_flags,
1678 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
1680 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
1681 if (!bs->read_only && bdrv_is_whitelisted(drv, true)) {
1682 ret = bdrv_apply_auto_read_only(bs, NULL, NULL);
1688 !bs->read_only && bdrv_is_whitelisted(drv, true)
1689 ? "Driver '%s' can only be used for read-only devices"
1690 : "Driver '%s' is not whitelisted",
1696 /* bdrv_new() and bdrv_close() make it so */
1697 assert(atomic_read(&bs->copy_on_read) == 0);
1699 if (bs->open_flags & BDRV_O_COPY_ON_READ) {
1700 if (!bs->read_only) {
1701 bdrv_enable_copy_on_read(bs);
1703 error_setg(errp, "Can't use copy-on-read on read-only device");
1709 discard = qemu_opt_get(opts, BDRV_OPT_DISCARD);
1710 if (discard != NULL) {
1711 if (bdrv_parse_discard_flags(discard, &bs->open_flags) != 0) {
1712 error_setg(errp, "Invalid discard option");
1719 bdrv_parse_detect_zeroes(opts, bs->open_flags, &local_err);
1721 error_propagate(errp, local_err);
1726 if (filename != NULL) {
1727 pstrcpy(bs->filename, sizeof(bs->filename), filename);
1729 bs->filename[0] = '\0';
1731 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename);
1733 /* Open the image, either directly or using a protocol */
1734 open_flags = bdrv_open_flags(bs, bs->open_flags);
1735 node_name = qemu_opt_get(opts, "node-name");
1737 assert(!drv->bdrv_file_open || file == NULL);
1738 ret = bdrv_open_driver(bs, drv, node_name, options, open_flags, errp);
1743 qemu_opts_del(opts);
1747 qemu_opts_del(opts);
1751 static QDict *parse_json_filename(const char *filename, Error **errp)
1753 QObject *options_obj;
1757 ret = strstart(filename, "json:", &filename);
1760 options_obj = qobject_from_json(filename, errp);
1762 error_prepend(errp, "Could not parse the JSON options: ");
1766 options = qobject_to(QDict, options_obj);
1768 qobject_unref(options_obj);
1769 error_setg(errp, "Invalid JSON object given");
1773 qdict_flatten(options);
1778 static void parse_json_protocol(QDict *options, const char **pfilename,
1781 QDict *json_options;
1782 Error *local_err = NULL;
1784 /* Parse json: pseudo-protocol */
1785 if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) {
1789 json_options = parse_json_filename(*pfilename, &local_err);
1791 error_propagate(errp, local_err);
1795 /* Options given in the filename have lower priority than options
1796 * specified directly */
1797 qdict_join(options, json_options, false);
1798 qobject_unref(json_options);
1803 * Fills in default options for opening images and converts the legacy
1804 * filename/flags pair to option QDict entries.
1805 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1806 * block driver has been specified explicitly.
1808 static int bdrv_fill_options(QDict **options, const char *filename,
1809 int *flags, Error **errp)
1811 const char *drvname;
1812 bool protocol = *flags & BDRV_O_PROTOCOL;
1813 bool parse_filename = false;
1814 BlockDriver *drv = NULL;
1815 Error *local_err = NULL;
1818 * Caution: while qdict_get_try_str() is fine, getting non-string
1819 * types would require more care. When @options come from
1820 * -blockdev or blockdev_add, its members are typed according to
1821 * the QAPI schema, but when they come from -drive, they're all
1824 drvname = qdict_get_try_str(*options, "driver");
1826 drv = bdrv_find_format(drvname);
1828 error_setg(errp, "Unknown driver '%s'", drvname);
1831 /* If the user has explicitly specified the driver, this choice should
1832 * override the BDRV_O_PROTOCOL flag */
1833 protocol = drv->bdrv_file_open;
1837 *flags |= BDRV_O_PROTOCOL;
1839 *flags &= ~BDRV_O_PROTOCOL;
1842 /* Translate cache options from flags into options */
1843 update_options_from_flags(*options, *flags);
1845 /* Fetch the file name from the options QDict if necessary */
1846 if (protocol && filename) {
1847 if (!qdict_haskey(*options, "filename")) {
1848 qdict_put_str(*options, "filename", filename);
1849 parse_filename = true;
1851 error_setg(errp, "Can't specify 'file' and 'filename' options at "
1857 /* Find the right block driver */
1858 /* See cautionary note on accessing @options above */
1859 filename = qdict_get_try_str(*options, "filename");
1861 if (!drvname && protocol) {
1863 drv = bdrv_find_protocol(filename, parse_filename, errp);
1868 drvname = drv->format_name;
1869 qdict_put_str(*options, "driver", drvname);
1871 error_setg(errp, "Must specify either driver or file");
1876 assert(drv || !protocol);
1878 /* Driver-specific filename parsing */
1879 if (drv && drv->bdrv_parse_filename && parse_filename) {
1880 drv->bdrv_parse_filename(filename, *options, &local_err);
1882 error_propagate(errp, local_err);
1886 if (!drv->bdrv_needs_filename) {
1887 qdict_del(*options, "filename");
1894 static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q,
1895 uint64_t perm, uint64_t shared,
1896 GSList *ignore_children,
1897 bool *tighten_restrictions, Error **errp);
1898 static void bdrv_child_abort_perm_update(BdrvChild *c);
1899 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared);
1901 typedef struct BlockReopenQueueEntry {
1904 BDRVReopenState state;
1905 QTAILQ_ENTRY(BlockReopenQueueEntry) entry;
1906 } BlockReopenQueueEntry;
1909 * Return the flags that @bs will have after the reopens in @q have
1910 * successfully completed. If @q is NULL (or @bs is not contained in @q),
1911 * return the current flags.
1913 static int bdrv_reopen_get_flags(BlockReopenQueue *q, BlockDriverState *bs)
1915 BlockReopenQueueEntry *entry;
1918 QTAILQ_FOREACH(entry, q, entry) {
1919 if (entry->state.bs == bs) {
1920 return entry->state.flags;
1925 return bs->open_flags;
1928 /* Returns whether the image file can be written to after the reopen queue @q
1929 * has been successfully applied, or right now if @q is NULL. */
1930 static bool bdrv_is_writable_after_reopen(BlockDriverState *bs,
1931 BlockReopenQueue *q)
1933 int flags = bdrv_reopen_get_flags(q, bs);
1935 return (flags & (BDRV_O_RDWR | BDRV_O_INACTIVE)) == BDRV_O_RDWR;
1939 * Return whether the BDS can be written to. This is not necessarily
1940 * the same as !bdrv_is_read_only(bs), as inactivated images may not
1941 * be written to but do not count as read-only images.
1943 bool bdrv_is_writable(BlockDriverState *bs)
1945 return bdrv_is_writable_after_reopen(bs, NULL);
1948 static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs,
1949 BdrvChild *c, BdrvChildRole role,
1950 BlockReopenQueue *reopen_queue,
1951 uint64_t parent_perm, uint64_t parent_shared,
1952 uint64_t *nperm, uint64_t *nshared)
1954 assert(bs->drv && bs->drv->bdrv_child_perm);
1955 bs->drv->bdrv_child_perm(bs, c, role, reopen_queue,
1956 parent_perm, parent_shared,
1958 /* TODO Take force_share from reopen_queue */
1959 if (child_bs && child_bs->force_share) {
1960 *nshared = BLK_PERM_ALL;
1965 * Check whether permissions on this node can be changed in a way that
1966 * @cumulative_perms and @cumulative_shared_perms are the new cumulative
1967 * permissions of all its parents. This involves checking whether all necessary
1968 * permission changes to child nodes can be performed.
1970 * Will set *tighten_restrictions to true if and only if new permissions have to
1971 * be taken or currently shared permissions are to be unshared. Otherwise,
1972 * errors are not fatal as long as the caller accepts that the restrictions
1973 * remain tighter than they need to be. The caller still has to abort the
1975 * @tighten_restrictions cannot be used together with @q: When reopening, we may
1976 * encounter fatal errors even though no restrictions are to be tightened. For
1977 * example, changing a node from RW to RO will fail if the WRITE permission is
1980 * A call to this function must always be followed by a call to bdrv_set_perm()
1981 * or bdrv_abort_perm_update().
1983 static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
1984 uint64_t cumulative_perms,
1985 uint64_t cumulative_shared_perms,
1986 GSList *ignore_children,
1987 bool *tighten_restrictions, Error **errp)
1989 BlockDriver *drv = bs->drv;
1993 assert(!q || !tighten_restrictions);
1995 if (tighten_restrictions) {
1996 uint64_t current_perms, current_shared;
1997 uint64_t added_perms, removed_shared_perms;
1999 bdrv_get_cumulative_perm(bs, ¤t_perms, ¤t_shared);
2001 added_perms = cumulative_perms & ~current_perms;
2002 removed_shared_perms = current_shared & ~cumulative_shared_perms;
2004 *tighten_restrictions = added_perms || removed_shared_perms;
2007 /* Write permissions never work with read-only images */
2008 if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) &&
2009 !bdrv_is_writable_after_reopen(bs, q))
2011 if (!bdrv_is_writable_after_reopen(bs, NULL)) {
2012 error_setg(errp, "Block node is read-only");
2014 uint64_t current_perms, current_shared;
2015 bdrv_get_cumulative_perm(bs, ¤t_perms, ¤t_shared);
2016 if (current_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) {
2017 error_setg(errp, "Cannot make block node read-only, there is "
2020 error_setg(errp, "Cannot make block node read-only and create "
2029 * Unaligned requests will automatically be aligned to bl.request_alignment
2030 * and without RESIZE we can't extend requests to write to space beyond the
2031 * end of the image, so it's required that the image size is aligned.
2033 if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) &&
2034 !(cumulative_perms & BLK_PERM_RESIZE))
2036 if ((bs->total_sectors * BDRV_SECTOR_SIZE) % bs->bl.request_alignment) {
2037 error_setg(errp, "Cannot get 'write' permission without 'resize': "
2038 "Image size is not a multiple of request "
2044 /* Check this node */
2049 if (drv->bdrv_check_perm) {
2050 return drv->bdrv_check_perm(bs, cumulative_perms,
2051 cumulative_shared_perms, errp);
2054 /* Drivers that never have children can omit .bdrv_child_perm() */
2055 if (!drv->bdrv_child_perm) {
2056 assert(QLIST_EMPTY(&bs->children));
2060 /* Check all children */
2061 QLIST_FOREACH(c, &bs->children, next) {
2062 uint64_t cur_perm, cur_shared;
2063 bool child_tighten_restr;
2065 bdrv_child_perm(bs, c->bs, c, c->role, q,
2066 cumulative_perms, cumulative_shared_perms,
2067 &cur_perm, &cur_shared);
2068 ret = bdrv_child_check_perm(c, q, cur_perm, cur_shared, ignore_children,
2069 tighten_restrictions ? &child_tighten_restr
2072 if (tighten_restrictions) {
2073 *tighten_restrictions |= child_tighten_restr;
2084 * Notifies drivers that after a previous bdrv_check_perm() call, the
2085 * permission update is not performed and any preparations made for it (e.g.
2086 * taken file locks) need to be undone.
2088 * This function recursively notifies all child nodes.
2090 static void bdrv_abort_perm_update(BlockDriverState *bs)
2092 BlockDriver *drv = bs->drv;
2099 if (drv->bdrv_abort_perm_update) {
2100 drv->bdrv_abort_perm_update(bs);
2103 QLIST_FOREACH(c, &bs->children, next) {
2104 bdrv_child_abort_perm_update(c);
2108 static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms,
2109 uint64_t cumulative_shared_perms)
2111 BlockDriver *drv = bs->drv;
2118 /* Update this node */
2119 if (drv->bdrv_set_perm) {
2120 drv->bdrv_set_perm(bs, cumulative_perms, cumulative_shared_perms);
2123 /* Drivers that never have children can omit .bdrv_child_perm() */
2124 if (!drv->bdrv_child_perm) {
2125 assert(QLIST_EMPTY(&bs->children));
2129 /* Update all children */
2130 QLIST_FOREACH(c, &bs->children, next) {
2131 uint64_t cur_perm, cur_shared;
2132 bdrv_child_perm(bs, c->bs, c, c->role, NULL,
2133 cumulative_perms, cumulative_shared_perms,
2134 &cur_perm, &cur_shared);
2135 bdrv_child_set_perm(c, cur_perm, cur_shared);
2139 void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm,
2140 uint64_t *shared_perm)
2143 uint64_t cumulative_perms = 0;
2144 uint64_t cumulative_shared_perms = BLK_PERM_ALL;
2146 QLIST_FOREACH(c, &bs->parents, next_parent) {
2147 cumulative_perms |= c->perm;
2148 cumulative_shared_perms &= c->shared_perm;
2151 *perm = cumulative_perms;
2152 *shared_perm = cumulative_shared_perms;
2155 static char *bdrv_child_user_desc(BdrvChild *c)
2157 if (c->klass->get_parent_desc) {
2158 return c->klass->get_parent_desc(c);
2161 return g_strdup("another user");
2164 char *bdrv_perm_names(uint64_t perm)
2170 { BLK_PERM_CONSISTENT_READ, "consistent read" },
2171 { BLK_PERM_WRITE, "write" },
2172 { BLK_PERM_WRITE_UNCHANGED, "write unchanged" },
2173 { BLK_PERM_RESIZE, "resize" },
2174 { BLK_PERM_GRAPH_MOD, "change children" },
2178 GString *result = g_string_sized_new(30);
2179 struct perm_name *p;
2181 for (p = permissions; p->name; p++) {
2182 if (perm & p->perm) {
2183 if (result->len > 0) {
2184 g_string_append(result, ", ");
2186 g_string_append(result, p->name);
2190 return g_string_free(result, FALSE);
2194 * Checks whether a new reference to @bs can be added if the new user requires
2195 * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is
2196 * set, the BdrvChild objects in this list are ignored in the calculations;
2197 * this allows checking permission updates for an existing reference.
2199 * See bdrv_check_perm() for the semantics of @tighten_restrictions.
2201 * Needs to be followed by a call to either bdrv_set_perm() or
2202 * bdrv_abort_perm_update(). */
2203 static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q,
2204 uint64_t new_used_perm,
2205 uint64_t new_shared_perm,
2206 GSList *ignore_children,
2207 bool *tighten_restrictions,
2211 uint64_t cumulative_perms = new_used_perm;
2212 uint64_t cumulative_shared_perms = new_shared_perm;
2214 assert(!q || !tighten_restrictions);
2216 /* There is no reason why anyone couldn't tolerate write_unchanged */
2217 assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED);
2219 QLIST_FOREACH(c, &bs->parents, next_parent) {
2220 if (g_slist_find(ignore_children, c)) {
2224 if ((new_used_perm & c->shared_perm) != new_used_perm) {
2225 char *user = bdrv_child_user_desc(c);
2226 char *perm_names = bdrv_perm_names(new_used_perm & ~c->shared_perm);
2228 if (tighten_restrictions) {
2229 *tighten_restrictions = true;
2232 error_setg(errp, "Conflicts with use by %s as '%s', which does not "
2234 user, c->name, perm_names, bdrv_get_node_name(c->bs));
2240 if ((c->perm & new_shared_perm) != c->perm) {
2241 char *user = bdrv_child_user_desc(c);
2242 char *perm_names = bdrv_perm_names(c->perm & ~new_shared_perm);
2244 if (tighten_restrictions) {
2245 *tighten_restrictions = true;
2248 error_setg(errp, "Conflicts with use by %s as '%s', which uses "
2250 user, c->name, perm_names, bdrv_get_node_name(c->bs));
2256 cumulative_perms |= c->perm;
2257 cumulative_shared_perms &= c->shared_perm;
2260 return bdrv_check_perm(bs, q, cumulative_perms, cumulative_shared_perms,
2261 ignore_children, tighten_restrictions, errp);
2264 /* Needs to be followed by a call to either bdrv_child_set_perm() or
2265 * bdrv_child_abort_perm_update(). */
2266 static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q,
2267 uint64_t perm, uint64_t shared,
2268 GSList *ignore_children,
2269 bool *tighten_restrictions, Error **errp)
2273 ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c);
2274 ret = bdrv_check_update_perm(c->bs, q, perm, shared, ignore_children,
2275 tighten_restrictions, errp);
2276 g_slist_free(ignore_children);
2282 if (!c->has_backup_perm) {
2283 c->has_backup_perm = true;
2284 c->backup_perm = c->perm;
2285 c->backup_shared_perm = c->shared_perm;
2288 * Note: it's OK if c->has_backup_perm was already set, as we can find the
2289 * same child twice during check_perm procedure
2293 c->shared_perm = shared;
2298 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared)
2300 uint64_t cumulative_perms, cumulative_shared_perms;
2302 c->has_backup_perm = false;
2305 c->shared_perm = shared;
2307 bdrv_get_cumulative_perm(c->bs, &cumulative_perms,
2308 &cumulative_shared_perms);
2309 bdrv_set_perm(c->bs, cumulative_perms, cumulative_shared_perms);
2312 static void bdrv_child_abort_perm_update(BdrvChild *c)
2314 if (c->has_backup_perm) {
2315 c->perm = c->backup_perm;
2316 c->shared_perm = c->backup_shared_perm;
2317 c->has_backup_perm = false;
2320 bdrv_abort_perm_update(c->bs);
2323 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
2326 Error *local_err = NULL;
2328 bool tighten_restrictions;
2330 ret = bdrv_child_check_perm(c, NULL, perm, shared, NULL,
2331 &tighten_restrictions, &local_err);
2333 bdrv_child_abort_perm_update(c);
2334 if (tighten_restrictions) {
2335 error_propagate(errp, local_err);
2338 * Our caller may intend to only loosen restrictions and
2339 * does not expect this function to fail. Errors are not
2340 * fatal in such a case, so we can just hide them from our
2343 error_free(local_err);
2349 bdrv_child_set_perm(c, perm, shared);
2354 int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp)
2356 uint64_t parent_perms, parent_shared;
2357 uint64_t perms, shared;
2359 bdrv_get_cumulative_perm(bs, &parent_perms, &parent_shared);
2360 bdrv_child_perm(bs, c->bs, c, c->role, NULL,
2361 parent_perms, parent_shared, &perms, &shared);
2363 return bdrv_child_try_set_perm(c, perms, shared, errp);
2367 * Default implementation for .bdrv_child_perm() for block filters:
2368 * Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED, and RESIZE to the
2371 static void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
2373 BlockReopenQueue *reopen_queue,
2374 uint64_t perm, uint64_t shared,
2375 uint64_t *nperm, uint64_t *nshared)
2377 *nperm = perm & DEFAULT_PERM_PASSTHROUGH;
2378 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
2381 static void bdrv_default_perms_for_cow(BlockDriverState *bs, BdrvChild *c,
2383 BlockReopenQueue *reopen_queue,
2384 uint64_t perm, uint64_t shared,
2385 uint64_t *nperm, uint64_t *nshared)
2387 assert(role & BDRV_CHILD_COW);
2390 * We want consistent read from backing files if the parent needs it.
2391 * No other operations are performed on backing files.
2393 perm &= BLK_PERM_CONSISTENT_READ;
2396 * If the parent can deal with changing data, we're okay with a
2397 * writable and resizable backing file.
2398 * TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too?
2400 if (shared & BLK_PERM_WRITE) {
2401 shared = BLK_PERM_WRITE | BLK_PERM_RESIZE;
2406 shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD |
2407 BLK_PERM_WRITE_UNCHANGED;
2409 if (bs->open_flags & BDRV_O_INACTIVE) {
2410 shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
2417 static void bdrv_default_perms_for_storage(BlockDriverState *bs, BdrvChild *c,
2419 BlockReopenQueue *reopen_queue,
2420 uint64_t perm, uint64_t shared,
2421 uint64_t *nperm, uint64_t *nshared)
2425 assert(role & (BDRV_CHILD_METADATA | BDRV_CHILD_DATA));
2427 flags = bdrv_reopen_get_flags(reopen_queue, bs);
2430 * Apart from the modifications below, the same permissions are
2431 * forwarded and left alone as for filters
2433 bdrv_filter_default_perms(bs, c, role, reopen_queue,
2434 perm, shared, &perm, &shared);
2436 if (role & BDRV_CHILD_METADATA) {
2437 /* Format drivers may touch metadata even if the guest doesn't write */
2438 if (bdrv_is_writable_after_reopen(bs, reopen_queue)) {
2439 perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
2443 * bs->file always needs to be consistent because of the
2444 * metadata. We can never allow other users to resize or write
2447 if (!(flags & BDRV_O_NO_IO)) {
2448 perm |= BLK_PERM_CONSISTENT_READ;
2450 shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
2453 if (role & BDRV_CHILD_DATA) {
2455 * Technically, everything in this block is a subset of the
2456 * BDRV_CHILD_METADATA path taken above, and so this could
2457 * be an "else if" branch. However, that is not obvious, and
2458 * this function is not performance critical, therefore we let
2459 * this be an independent "if".
2463 * We cannot allow other users to resize the file because the
2464 * format driver might have some assumptions about the size
2465 * (e.g. because it is stored in metadata, or because the file
2466 * is split into fixed-size data files).
2468 shared &= ~BLK_PERM_RESIZE;
2471 * WRITE_UNCHANGED often cannot be performed as such on the
2472 * data file. For example, the qcow2 driver may still need to
2473 * write copied clusters on copy-on-read.
2475 if (perm & BLK_PERM_WRITE_UNCHANGED) {
2476 perm |= BLK_PERM_WRITE;
2480 * If the data file is written to, the format driver may
2481 * expect to be able to resize it by writing beyond the EOF.
2483 if (perm & BLK_PERM_WRITE) {
2484 perm |= BLK_PERM_RESIZE;
2488 if (bs->open_flags & BDRV_O_INACTIVE) {
2489 shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
2496 void bdrv_default_perms(BlockDriverState *bs, BdrvChild *c,
2497 BdrvChildRole role, BlockReopenQueue *reopen_queue,
2498 uint64_t perm, uint64_t shared,
2499 uint64_t *nperm, uint64_t *nshared)
2501 if (role & BDRV_CHILD_FILTERED) {
2502 assert(!(role & (BDRV_CHILD_DATA | BDRV_CHILD_METADATA |
2504 bdrv_filter_default_perms(bs, c, role, reopen_queue,
2505 perm, shared, nperm, nshared);
2506 } else if (role & BDRV_CHILD_COW) {
2507 assert(!(role & (BDRV_CHILD_DATA | BDRV_CHILD_METADATA)));
2508 bdrv_default_perms_for_cow(bs, c, role, reopen_queue,
2509 perm, shared, nperm, nshared);
2510 } else if (role & (BDRV_CHILD_METADATA | BDRV_CHILD_DATA)) {
2511 bdrv_default_perms_for_storage(bs, c, role, reopen_queue,
2512 perm, shared, nperm, nshared);
2514 g_assert_not_reached();
2518 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm)
2520 static const uint64_t permissions[] = {
2521 [BLOCK_PERMISSION_CONSISTENT_READ] = BLK_PERM_CONSISTENT_READ,
2522 [BLOCK_PERMISSION_WRITE] = BLK_PERM_WRITE,
2523 [BLOCK_PERMISSION_WRITE_UNCHANGED] = BLK_PERM_WRITE_UNCHANGED,
2524 [BLOCK_PERMISSION_RESIZE] = BLK_PERM_RESIZE,
2525 [BLOCK_PERMISSION_GRAPH_MOD] = BLK_PERM_GRAPH_MOD,
2528 QEMU_BUILD_BUG_ON(ARRAY_SIZE(permissions) != BLOCK_PERMISSION__MAX);
2529 QEMU_BUILD_BUG_ON(1UL << ARRAY_SIZE(permissions) != BLK_PERM_ALL + 1);
2531 assert(qapi_perm < BLOCK_PERMISSION__MAX);
2533 return permissions[qapi_perm];
2536 static void bdrv_replace_child_noperm(BdrvChild *child,
2537 BlockDriverState *new_bs)
2539 BlockDriverState *old_bs = child->bs;
2540 int new_bs_quiesce_counter;
2543 assert(!child->frozen);
2545 if (old_bs && new_bs) {
2546 assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs));
2549 new_bs_quiesce_counter = (new_bs ? new_bs->quiesce_counter : 0);
2550 drain_saldo = new_bs_quiesce_counter - child->parent_quiesce_counter;
2553 * If the new child node is drained but the old one was not, flush
2554 * all outstanding requests to the old child node.
2556 while (drain_saldo > 0 && child->klass->drained_begin) {
2557 bdrv_parent_drained_begin_single(child, true);
2562 /* Detach first so that the recursive drain sections coming from @child
2563 * are already gone and we only end the drain sections that came from
2565 if (child->klass->detach) {
2566 child->klass->detach(child);
2568 QLIST_REMOVE(child, next_parent);
2574 QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
2577 * Detaching the old node may have led to the new node's
2578 * quiesce_counter having been decreased. Not a problem, we
2579 * just need to recognize this here and then invoke
2580 * drained_end appropriately more often.
2582 assert(new_bs->quiesce_counter <= new_bs_quiesce_counter);
2583 drain_saldo += new_bs->quiesce_counter - new_bs_quiesce_counter;
2585 /* Attach only after starting new drained sections, so that recursive
2586 * drain sections coming from @child don't get an extra .drained_begin
2588 if (child->klass->attach) {
2589 child->klass->attach(child);
2594 * If the old child node was drained but the new one is not, allow
2595 * requests to come in only after the new node has been attached.
2597 while (drain_saldo < 0 && child->klass->drained_end) {
2598 bdrv_parent_drained_end_single(child);
2604 * Updates @child to change its reference to point to @new_bs, including
2605 * checking and applying the necessary permission updates both to the old node
2608 * NULL is passed as @new_bs for removing the reference before freeing @child.
2610 * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this
2611 * function uses bdrv_set_perm() to update the permissions according to the new
2612 * reference that @new_bs gets.
2614 * Callers must ensure that child->frozen is false.
2616 static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
2618 BlockDriverState *old_bs = child->bs;
2619 uint64_t perm, shared_perm;
2621 /* Asserts that child->frozen == false */
2622 bdrv_replace_child_noperm(child, new_bs);
2625 * Start with the new node's permissions. If @new_bs is a (direct
2626 * or indirect) child of @old_bs, we must complete the permission
2627 * update on @new_bs before we loosen the restrictions on @old_bs.
2628 * Otherwise, bdrv_check_perm() on @old_bs would re-initiate
2629 * updating the permissions of @new_bs, and thus not purely loosen
2633 bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm);
2634 bdrv_set_perm(new_bs, perm, shared_perm);
2638 /* Update permissions for old node. This is guaranteed to succeed
2639 * because we're just taking a parent away, so we're loosening
2641 bool tighten_restrictions;
2644 bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm);
2645 ret = bdrv_check_perm(old_bs, NULL, perm, shared_perm, NULL,
2646 &tighten_restrictions, NULL);
2647 assert(tighten_restrictions == false);
2649 /* We only tried to loosen restrictions, so errors are not fatal */
2650 bdrv_abort_perm_update(old_bs);
2652 bdrv_set_perm(old_bs, perm, shared_perm);
2655 /* When the parent requiring a non-default AioContext is removed, the
2656 * node moves back to the main AioContext */
2657 bdrv_try_set_aio_context(old_bs, qemu_get_aio_context(), NULL);
2662 * This function steals the reference to child_bs from the caller.
2663 * That reference is later dropped by bdrv_root_unref_child().
2665 * On failure NULL is returned, errp is set and the reference to
2666 * child_bs is also dropped.
2668 * The caller must hold the AioContext lock @child_bs, but not that of @ctx
2669 * (unless @child_bs is already in @ctx).
2671 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
2672 const char *child_name,
2673 const BdrvChildClass *child_class,
2674 BdrvChildRole child_role,
2676 uint64_t perm, uint64_t shared_perm,
2677 void *opaque, Error **errp)
2680 Error *local_err = NULL;
2683 ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, NULL,
2686 bdrv_abort_perm_update(child_bs);
2687 bdrv_unref(child_bs);
2691 child = g_new(BdrvChild, 1);
2692 *child = (BdrvChild) {
2694 .name = g_strdup(child_name),
2695 .klass = child_class,
2698 .shared_perm = shared_perm,
2702 /* If the AioContexts don't match, first try to move the subtree of
2703 * child_bs into the AioContext of the new parent. If this doesn't work,
2704 * try moving the parent into the AioContext of child_bs instead. */
2705 if (bdrv_get_aio_context(child_bs) != ctx) {
2706 ret = bdrv_try_set_aio_context(child_bs, ctx, &local_err);
2707 if (ret < 0 && child_class->can_set_aio_ctx) {
2708 GSList *ignore = g_slist_prepend(NULL, child);
2709 ctx = bdrv_get_aio_context(child_bs);
2710 if (child_class->can_set_aio_ctx(child, ctx, &ignore, NULL)) {
2711 error_free(local_err);
2713 g_slist_free(ignore);
2714 ignore = g_slist_prepend(NULL, child);
2715 child_class->set_aio_ctx(child, ctx, &ignore);
2717 g_slist_free(ignore);
2720 error_propagate(errp, local_err);
2722 bdrv_abort_perm_update(child_bs);
2723 bdrv_unref(child_bs);
2728 /* This performs the matching bdrv_set_perm() for the above check. */
2729 bdrv_replace_child(child, child_bs);
2735 * This function transfers the reference to child_bs from the caller
2736 * to parent_bs. That reference is later dropped by parent_bs on
2737 * bdrv_close() or if someone calls bdrv_unref_child().
2739 * On failure NULL is returned, errp is set and the reference to
2740 * child_bs is also dropped.
2742 * If @parent_bs and @child_bs are in different AioContexts, the caller must
2743 * hold the AioContext lock for @child_bs, but not for @parent_bs.
2745 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
2746 BlockDriverState *child_bs,
2747 const char *child_name,
2748 const BdrvChildClass *child_class,
2749 BdrvChildRole child_role,
2753 uint64_t perm, shared_perm;
2755 bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm);
2757 assert(parent_bs->drv);
2758 bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL,
2759 perm, shared_perm, &perm, &shared_perm);
2761 child = bdrv_root_attach_child(child_bs, child_name, child_class,
2762 child_role, bdrv_get_aio_context(parent_bs),
2763 perm, shared_perm, parent_bs, errp);
2764 if (child == NULL) {
2768 QLIST_INSERT_HEAD(&parent_bs->children, child, next);
2772 static void bdrv_detach_child(BdrvChild *child)
2774 QLIST_SAFE_REMOVE(child, next);
2776 bdrv_replace_child(child, NULL);
2778 g_free(child->name);
2782 /* Callers must ensure that child->frozen is false. */
2783 void bdrv_root_unref_child(BdrvChild *child)
2785 BlockDriverState *child_bs;
2787 child_bs = child->bs;
2788 bdrv_detach_child(child);
2789 bdrv_unref(child_bs);
2793 * Clear all inherits_from pointers from children and grandchildren of
2794 * @root that point to @root, where necessary.
2796 static void bdrv_unset_inherits_from(BlockDriverState *root, BdrvChild *child)
2800 if (child->bs->inherits_from == root) {
2802 * Remove inherits_from only when the last reference between root and
2803 * child->bs goes away.
2805 QLIST_FOREACH(c, &root->children, next) {
2806 if (c != child && c->bs == child->bs) {
2811 child->bs->inherits_from = NULL;
2815 QLIST_FOREACH(c, &child->bs->children, next) {
2816 bdrv_unset_inherits_from(root, c);
2820 /* Callers must ensure that child->frozen is false. */
2821 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child)
2823 if (child == NULL) {
2827 bdrv_unset_inherits_from(parent, child);
2828 bdrv_root_unref_child(child);
2832 static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load)
2835 QLIST_FOREACH(c, &bs->parents, next_parent) {
2836 if (c->klass->change_media) {
2837 c->klass->change_media(c, load);
2842 /* Return true if you can reach parent going through child->inherits_from
2843 * recursively. If parent or child are NULL, return false */
2844 static bool bdrv_inherits_from_recursive(BlockDriverState *child,
2845 BlockDriverState *parent)
2847 while (child && child != parent) {
2848 child = child->inherits_from;
2851 return child != NULL;
2855 * Return the BdrvChildRole for @bs's backing child. bs->backing is
2856 * mostly used for COW backing children (role = COW), but also for
2857 * filtered children (role = FILTERED | PRIMARY).
2859 static BdrvChildRole bdrv_backing_role(BlockDriverState *bs)
2861 if (bs->drv && bs->drv->is_filter) {
2862 return BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY;
2864 return BDRV_CHILD_COW;
2869 * Sets the bs->backing link of a BDS. A new reference is created; callers
2870 * which don't need their own reference any more must call bdrv_unref().
2872 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
2875 bool update_inherits_from = bdrv_chain_contains(bs, backing_hd) &&
2876 bdrv_inherits_from_recursive(backing_hd, bs);
2878 if (bdrv_is_backing_chain_frozen(bs, child_bs(bs->backing), errp)) {
2883 bdrv_ref(backing_hd);
2887 /* Cannot be frozen, we checked that above */
2888 bdrv_unref_child(bs, bs->backing);
2896 bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_of_bds,
2897 bdrv_backing_role(bs), errp);
2898 /* If backing_hd was already part of bs's backing chain, and
2899 * inherits_from pointed recursively to bs then let's update it to
2900 * point directly to bs (else it will become NULL). */
2901 if (bs->backing && update_inherits_from) {
2902 backing_hd->inherits_from = bs;
2906 bdrv_refresh_limits(bs, NULL);
2910 * Opens the backing file for a BlockDriverState if not yet open
2912 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
2913 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2914 * itself, all options starting with "${bdref_key}." are considered part of the
2917 * TODO Can this be unified with bdrv_open_image()?
2919 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
2920 const char *bdref_key, Error **errp)
2922 char *backing_filename = NULL;
2923 char *bdref_key_dot;
2924 const char *reference = NULL;
2926 bool implicit_backing = false;
2927 BlockDriverState *backing_hd;
2929 QDict *tmp_parent_options = NULL;
2930 Error *local_err = NULL;
2932 if (bs->backing != NULL) {
2936 /* NULL means an empty set of options */
2937 if (parent_options == NULL) {
2938 tmp_parent_options = qdict_new();
2939 parent_options = tmp_parent_options;
2942 bs->open_flags &= ~BDRV_O_NO_BACKING;
2944 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
2945 qdict_extract_subqdict(parent_options, &options, bdref_key_dot);
2946 g_free(bdref_key_dot);
2949 * Caution: while qdict_get_try_str() is fine, getting non-string
2950 * types would require more care. When @parent_options come from
2951 * -blockdev or blockdev_add, its members are typed according to
2952 * the QAPI schema, but when they come from -drive, they're all
2955 reference = qdict_get_try_str(parent_options, bdref_key);
2956 if (reference || qdict_haskey(options, "file.filename")) {
2957 /* keep backing_filename NULL */
2958 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
2959 qobject_unref(options);
2962 if (qdict_size(options) == 0) {
2963 /* If the user specifies options that do not modify the
2964 * backing file's behavior, we might still consider it the
2965 * implicit backing file. But it's easier this way, and
2966 * just specifying some of the backing BDS's options is
2967 * only possible with -drive anyway (otherwise the QAPI
2968 * schema forces the user to specify everything). */
2969 implicit_backing = !strcmp(bs->auto_backing_file, bs->backing_file);
2972 backing_filename = bdrv_get_full_backing_filename(bs, &local_err);
2975 error_propagate(errp, local_err);
2976 qobject_unref(options);
2981 if (!bs->drv || !bs->drv->supports_backing) {
2983 error_setg(errp, "Driver doesn't support backing files");
2984 qobject_unref(options);
2989 bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) {
2990 qdict_put_str(options, "driver", bs->backing_format);
2993 backing_hd = bdrv_open_inherit(backing_filename, reference, options, 0, bs,
2994 &child_of_bds, bdrv_backing_role(bs), errp);
2996 bs->open_flags |= BDRV_O_NO_BACKING;
2997 error_prepend(errp, "Could not open backing file: ");
3002 if (implicit_backing) {
3003 bdrv_refresh_filename(backing_hd);
3004 pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file),
3005 backing_hd->filename);
3008 /* Hook up the backing file link; drop our reference, bs owns the
3009 * backing_hd reference now */
3010 bdrv_set_backing_hd(bs, backing_hd, &local_err);
3011 bdrv_unref(backing_hd);
3013 error_propagate(errp, local_err);
3018 qdict_del(parent_options, bdref_key);
3021 g_free(backing_filename);
3022 qobject_unref(tmp_parent_options);
3026 static BlockDriverState *
3027 bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
3028 BlockDriverState *parent, const BdrvChildClass *child_class,
3029 BdrvChildRole child_role, bool allow_none, Error **errp)
3031 BlockDriverState *bs = NULL;
3032 QDict *image_options;
3033 char *bdref_key_dot;
3034 const char *reference;
3036 assert(child_class != NULL);
3038 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
3039 qdict_extract_subqdict(options, &image_options, bdref_key_dot);
3040 g_free(bdref_key_dot);
3043 * Caution: while qdict_get_try_str() is fine, getting non-string
3044 * types would require more care. When @options come from
3045 * -blockdev or blockdev_add, its members are typed according to
3046 * the QAPI schema, but when they come from -drive, they're all
3049 reference = qdict_get_try_str(options, bdref_key);
3050 if (!filename && !reference && !qdict_size(image_options)) {
3052 error_setg(errp, "A block device must be specified for \"%s\"",
3055 qobject_unref(image_options);
3059 bs = bdrv_open_inherit(filename, reference, image_options, 0,
3060 parent, child_class, child_role, errp);
3066 qdict_del(options, bdref_key);
3071 * Opens a disk image whose options are given as BlockdevRef in another block
3074 * If allow_none is true, no image will be opened if filename is false and no
3075 * BlockdevRef is given. NULL will be returned, but errp remains unset.
3077 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
3078 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
3079 * itself, all options starting with "${bdref_key}." are considered part of the
3082 * The BlockdevRef will be removed from the options QDict.
3084 BdrvChild *bdrv_open_child(const char *filename,
3085 QDict *options, const char *bdref_key,
3086 BlockDriverState *parent,
3087 const BdrvChildClass *child_class,
3088 BdrvChildRole child_role,
3089 bool allow_none, Error **errp)
3091 BlockDriverState *bs;
3093 bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_class,
3094 child_role, allow_none, errp);
3099 return bdrv_attach_child(parent, bs, bdref_key, child_class, child_role,
3104 * TODO Future callers may need to specify parent/child_class in order for
3105 * option inheritance to work. Existing callers use it for the root node.
3107 BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp)
3109 BlockDriverState *bs = NULL;
3110 QObject *obj = NULL;
3111 QDict *qdict = NULL;
3112 const char *reference = NULL;
3115 if (ref->type == QTYPE_QSTRING) {
3116 reference = ref->u.reference;
3118 BlockdevOptions *options = &ref->u.definition;
3119 assert(ref->type == QTYPE_QDICT);
3121 v = qobject_output_visitor_new(&obj);
3122 visit_type_BlockdevOptions(v, NULL, &options, &error_abort);
3123 visit_complete(v, &obj);
3125 qdict = qobject_to(QDict, obj);
3126 qdict_flatten(qdict);
3128 /* bdrv_open_inherit() defaults to the values in bdrv_flags (for
3129 * compatibility with other callers) rather than what we want as the
3130 * real defaults. Apply the defaults here instead. */
3131 qdict_set_default_str(qdict, BDRV_OPT_CACHE_DIRECT, "off");
3132 qdict_set_default_str(qdict, BDRV_OPT_CACHE_NO_FLUSH, "off");
3133 qdict_set_default_str(qdict, BDRV_OPT_READ_ONLY, "off");
3134 qdict_set_default_str(qdict, BDRV_OPT_AUTO_READ_ONLY, "off");
3138 bs = bdrv_open_inherit(NULL, reference, qdict, 0, NULL, NULL, 0, errp);
3145 static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
3147 QDict *snapshot_options,
3150 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
3151 char *tmp_filename = g_malloc0(PATH_MAX + 1);
3153 QemuOpts *opts = NULL;
3154 BlockDriverState *bs_snapshot = NULL;
3155 Error *local_err = NULL;
3158 /* if snapshot, we create a temporary backing file and open it
3159 instead of opening 'filename' directly */
3161 /* Get the required size from the image */
3162 total_size = bdrv_getlength(bs);
3163 if (total_size < 0) {
3164 error_setg_errno(errp, -total_size, "Could not get image size");
3168 /* Create the temporary image */
3169 ret = get_tmp_filename(tmp_filename, PATH_MAX + 1);
3171 error_setg_errno(errp, -ret, "Could not get temporary filename");
3175 opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0,
3177 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort);
3178 ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp);
3179 qemu_opts_del(opts);
3181 error_prepend(errp, "Could not create temporary overlay '%s': ",
3186 /* Prepare options QDict for the temporary file */
3187 qdict_put_str(snapshot_options, "file.driver", "file");
3188 qdict_put_str(snapshot_options, "file.filename", tmp_filename);
3189 qdict_put_str(snapshot_options, "driver", "qcow2");
3191 bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp);
3192 snapshot_options = NULL;
3197 /* bdrv_append() consumes a strong reference to bs_snapshot
3198 * (i.e. it will call bdrv_unref() on it) even on error, so in
3199 * order to be able to return one, we have to increase
3200 * bs_snapshot's refcount here */
3201 bdrv_ref(bs_snapshot);
3202 bdrv_append(bs_snapshot, bs, &local_err);
3204 error_propagate(errp, local_err);
3210 qobject_unref(snapshot_options);
3211 g_free(tmp_filename);
3216 * Opens a disk image (raw, qcow2, vmdk, ...)
3218 * options is a QDict of options to pass to the block drivers, or NULL for an
3219 * empty set of options. The reference to the QDict belongs to the block layer
3220 * after the call (even on failure), so if the caller intends to reuse the
3221 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
3223 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
3224 * If it is not NULL, the referenced BDS will be reused.
3226 * The reference parameter may be used to specify an existing block device which
3227 * should be opened. If specified, neither options nor a filename may be given,
3228 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
3230 static BlockDriverState *bdrv_open_inherit(const char *filename,
3231 const char *reference,
3232 QDict *options, int flags,
3233 BlockDriverState *parent,
3234 const BdrvChildClass *child_class,
3235 BdrvChildRole child_role,
3239 BlockBackend *file = NULL;
3240 BlockDriverState *bs;
3241 BlockDriver *drv = NULL;
3243 const char *drvname;
3244 const char *backing;
3245 Error *local_err = NULL;
3246 QDict *snapshot_options = NULL;
3247 int snapshot_flags = 0;
3249 assert(!child_class || !flags);
3250 assert(!child_class == !parent);
3253 bool options_non_empty = options ? qdict_size(options) : false;
3254 qobject_unref(options);
3256 if (filename || options_non_empty) {
3257 error_setg(errp, "Cannot reference an existing block device with "
3258 "additional options or a new filename");
3262 bs = bdrv_lookup_bs(reference, reference, errp);
3273 /* NULL means an empty set of options */
3274 if (options == NULL) {
3275 options = qdict_new();
3278 /* json: syntax counts as explicit options, as if in the QDict */
3279 parse_json_protocol(options, &filename, &local_err);
3284 bs->explicit_options = qdict_clone_shallow(options);
3287 bool parent_is_format;
3290 parent_is_format = parent->drv->is_format;
3293 * parent->drv is not set yet because this node is opened for
3294 * (potential) format probing. That means that @parent is going
3295 * to be a format node.
3297 parent_is_format = true;
3300 bs->inherits_from = parent;
3301 child_class->inherit_options(child_role, parent_is_format,
3303 parent->open_flags, parent->options);
3306 ret = bdrv_fill_options(&options, filename, &flags, &local_err);
3312 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
3313 * Caution: getting a boolean member of @options requires care.
3314 * When @options come from -blockdev or blockdev_add, members are
3315 * typed according to the QAPI schema, but when they come from
3316 * -drive, they're all QString.
3318 if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") &&
3319 !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) {
3320 flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR);
3322 flags &= ~BDRV_O_RDWR;
3325 if (flags & BDRV_O_SNAPSHOT) {
3326 snapshot_options = qdict_new();
3327 bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options,
3329 /* Let bdrv_backing_options() override "read-only" */
3330 qdict_del(options, BDRV_OPT_READ_ONLY);
3331 bdrv_inherited_options(BDRV_CHILD_COW, true,
3332 &flags, options, flags, options);
3335 bs->open_flags = flags;
3336 bs->options = options;
3337 options = qdict_clone_shallow(options);
3339 /* Find the right image format driver */
3340 /* See cautionary note on accessing @options above */
3341 drvname = qdict_get_try_str(options, "driver");
3343 drv = bdrv_find_format(drvname);
3345 error_setg(errp, "Unknown driver: '%s'", drvname);
3350 assert(drvname || !(flags & BDRV_O_PROTOCOL));
3352 /* See cautionary note on accessing @options above */
3353 backing = qdict_get_try_str(options, "backing");
3354 if (qobject_to(QNull, qdict_get(options, "backing")) != NULL ||
3355 (backing && *backing == '\0'))
3358 warn_report("Use of \"backing\": \"\" is deprecated; "
3359 "use \"backing\": null instead");
3361 flags |= BDRV_O_NO_BACKING;
3362 qdict_del(bs->explicit_options, "backing");
3363 qdict_del(bs->options, "backing");
3364 qdict_del(options, "backing");
3367 /* Open image file without format layer. This BlockBackend is only used for
3368 * probing, the block drivers will do their own bdrv_open_child() for the
3369 * same BDS, which is why we put the node name back into options. */
3370 if ((flags & BDRV_O_PROTOCOL) == 0) {
3371 BlockDriverState *file_bs;
3373 file_bs = bdrv_open_child_bs(filename, options, "file", bs,
3374 &child_of_bds, BDRV_CHILD_IMAGE,
3379 if (file_bs != NULL) {
3380 /* Not requesting BLK_PERM_CONSISTENT_READ because we're only
3381 * looking at the header to guess the image format. This works even
3382 * in cases where a guest would not see a consistent state. */
3383 file = blk_new(bdrv_get_aio_context(file_bs), 0, BLK_PERM_ALL);
3384 blk_insert_bs(file, file_bs, &local_err);
3385 bdrv_unref(file_bs);
3390 qdict_put_str(options, "file", bdrv_get_node_name(file_bs));
3394 /* Image format probing */
3397 ret = find_image_format(file, filename, &drv, &local_err);
3402 * This option update would logically belong in bdrv_fill_options(),
3403 * but we first need to open bs->file for the probing to work, while
3404 * opening bs->file already requires the (mostly) final set of options
3405 * so that cache mode etc. can be inherited.
3407 * Adding the driver later is somewhat ugly, but it's not an option
3408 * that would ever be inherited, so it's correct. We just need to make
3409 * sure to update both bs->options (which has the full effective
3410 * options for bs) and options (which has file.* already removed).
3412 qdict_put_str(bs->options, "driver", drv->format_name);
3413 qdict_put_str(options, "driver", drv->format_name);
3415 error_setg(errp, "Must specify either driver or file");
3419 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
3420 assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open);
3421 /* file must be NULL if a protocol BDS is about to be created
3422 * (the inverse results in an error message from bdrv_open_common()) */
3423 assert(!(flags & BDRV_O_PROTOCOL) || !file);
3425 /* Open the image */
3426 ret = bdrv_open_common(bs, file, options, &local_err);
3436 /* If there is a backing file, use it */
3437 if ((flags & BDRV_O_NO_BACKING) == 0) {
3438 ret = bdrv_open_backing_file(bs, options, "backing", &local_err);
3440 goto close_and_fail;
3444 /* Remove all children options and references
3445 * from bs->options and bs->explicit_options */
3446 QLIST_FOREACH(child, &bs->children, next) {
3447 char *child_key_dot;
3448 child_key_dot = g_strdup_printf("%s.", child->name);
3449 qdict_extract_subqdict(bs->explicit_options, NULL, child_key_dot);
3450 qdict_extract_subqdict(bs->options, NULL, child_key_dot);
3451 qdict_del(bs->explicit_options, child->name);
3452 qdict_del(bs->options, child->name);
3453 g_free(child_key_dot);
3456 /* Check if any unknown options were used */
3457 if (qdict_size(options) != 0) {
3458 const QDictEntry *entry = qdict_first(options);
3459 if (flags & BDRV_O_PROTOCOL) {
3460 error_setg(errp, "Block protocol '%s' doesn't support the option "
3461 "'%s'", drv->format_name, entry->key);
3464 "Block format '%s' does not support the option '%s'",
3465 drv->format_name, entry->key);
3468 goto close_and_fail;
3471 bdrv_parent_cb_change_media(bs, true);
3473 qobject_unref(options);
3476 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
3477 * temporary snapshot afterwards. */
3478 if (snapshot_flags) {
3479 BlockDriverState *snapshot_bs;
3480 snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags,
3481 snapshot_options, &local_err);
3482 snapshot_options = NULL;
3484 goto close_and_fail;
3486 /* We are not going to return bs but the overlay on top of it
3487 * (snapshot_bs); thus, we have to drop the strong reference to bs
3488 * (which we obtained by calling bdrv_new()). bs will not be deleted,
3489 * though, because the overlay still has a reference to it. */
3498 qobject_unref(snapshot_options);
3499 qobject_unref(bs->explicit_options);
3500 qobject_unref(bs->options);
3501 qobject_unref(options);
3503 bs->explicit_options = NULL;
3505 error_propagate(errp, local_err);
3510 qobject_unref(snapshot_options);
3511 qobject_unref(options);
3512 error_propagate(errp, local_err);
3516 BlockDriverState *bdrv_open(const char *filename, const char *reference,
3517 QDict *options, int flags, Error **errp)
3519 return bdrv_open_inherit(filename, reference, options, flags, NULL,
3523 /* Return true if the NULL-terminated @list contains @str */
3524 static bool is_str_in_list(const char *str, const char *const *list)
3528 for (i = 0; list[i] != NULL; i++) {
3529 if (!strcmp(str, list[i])) {
3538 * Check that every option set in @bs->options is also set in
3541 * Options listed in the common_options list and in
3542 * @bs->drv->mutable_opts are skipped.
3544 * Return 0 on success, otherwise return -EINVAL and set @errp.
3546 static int bdrv_reset_options_allowed(BlockDriverState *bs,
3547 const QDict *new_opts, Error **errp)
3549 const QDictEntry *e;
3550 /* These options are common to all block drivers and are handled
3551 * in bdrv_reopen_prepare() so they can be left out of @new_opts */
3552 const char *const common_options[] = {
3553 "node-name", "discard", "cache.direct", "cache.no-flush",
3554 "read-only", "auto-read-only", "detect-zeroes", NULL
3557 for (e = qdict_first(bs->options); e; e = qdict_next(bs->options, e)) {
3558 if (!qdict_haskey(new_opts, e->key) &&
3559 !is_str_in_list(e->key, common_options) &&
3560 !is_str_in_list(e->key, bs->drv->mutable_opts)) {
3561 error_setg(errp, "Option '%s' cannot be reset "
3562 "to its default value", e->key);
3571 * Returns true if @child can be reached recursively from @bs
3573 static bool bdrv_recurse_has_child(BlockDriverState *bs,
3574 BlockDriverState *child)
3582 QLIST_FOREACH(c, &bs->children, next) {
3583 if (bdrv_recurse_has_child(c->bs, child)) {
3592 * Adds a BlockDriverState to a simple queue for an atomic, transactional
3593 * reopen of multiple devices.
3595 * bs_queue can either be an existing BlockReopenQueue that has had QTAILQ_INIT
3596 * already performed, or alternatively may be NULL a new BlockReopenQueue will
3597 * be created and initialized. This newly created BlockReopenQueue should be
3598 * passed back in for subsequent calls that are intended to be of the same
3601 * bs is the BlockDriverState to add to the reopen queue.
3603 * options contains the changed options for the associated bs
3604 * (the BlockReopenQueue takes ownership)
3606 * flags contains the open flags for the associated bs
3608 * returns a pointer to bs_queue, which is either the newly allocated
3609 * bs_queue, or the existing bs_queue being used.
3611 * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple().
3613 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
3614 BlockDriverState *bs,
3616 const BdrvChildClass *klass,
3618 bool parent_is_format,
3619 QDict *parent_options,
3625 BlockReopenQueueEntry *bs_entry;
3627 QDict *old_options, *explicit_options, *options_copy;
3631 /* Make sure that the caller remembered to use a drained section. This is
3632 * important to avoid graph changes between the recursive queuing here and
3633 * bdrv_reopen_multiple(). */
3634 assert(bs->quiesce_counter > 0);
3636 if (bs_queue == NULL) {
3637 bs_queue = g_new0(BlockReopenQueue, 1);
3638 QTAILQ_INIT(bs_queue);
3642 options = qdict_new();
3645 /* Check if this BlockDriverState is already in the queue */
3646 QTAILQ_FOREACH(bs_entry, bs_queue, entry) {
3647 if (bs == bs_entry->state.bs) {
3653 * Precedence of options:
3654 * 1. Explicitly passed in options (highest)
3655 * 2. Retained from explicitly set options of bs
3656 * 3. Inherited from parent node
3657 * 4. Retained from effective options of bs
3660 /* Old explicitly set values (don't overwrite by inherited value) */
3661 if (bs_entry || keep_old_opts) {
3662 old_options = qdict_clone_shallow(bs_entry ?
3663 bs_entry->state.explicit_options :
3664 bs->explicit_options);
3665 bdrv_join_options(bs, options, old_options);
3666 qobject_unref(old_options);
3669 explicit_options = qdict_clone_shallow(options);
3671 /* Inherit from parent node */
3672 if (parent_options) {
3674 klass->inherit_options(role, parent_is_format, &flags, options,
3675 parent_flags, parent_options);
3677 flags = bdrv_get_flags(bs);
3680 if (keep_old_opts) {
3681 /* Old values are used for options that aren't set yet */
3682 old_options = qdict_clone_shallow(bs->options);
3683 bdrv_join_options(bs, options, old_options);
3684 qobject_unref(old_options);
3687 /* We have the final set of options so let's update the flags */
3688 options_copy = qdict_clone_shallow(options);
3689 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
3690 qemu_opts_absorb_qdict(opts, options_copy, NULL);
3691 update_flags_from_options(&flags, opts);
3692 qemu_opts_del(opts);
3693 qobject_unref(options_copy);
3695 /* bdrv_open_inherit() sets and clears some additional flags internally */
3696 flags &= ~BDRV_O_PROTOCOL;
3697 if (flags & BDRV_O_RDWR) {
3698 flags |= BDRV_O_ALLOW_RDWR;
3702 bs_entry = g_new0(BlockReopenQueueEntry, 1);
3703 QTAILQ_INSERT_TAIL(bs_queue, bs_entry, entry);
3705 qobject_unref(bs_entry->state.options);
3706 qobject_unref(bs_entry->state.explicit_options);
3709 bs_entry->state.bs = bs;
3710 bs_entry->state.options = options;
3711 bs_entry->state.explicit_options = explicit_options;
3712 bs_entry->state.flags = flags;
3714 /* This needs to be overwritten in bdrv_reopen_prepare() */
3715 bs_entry->state.perm = UINT64_MAX;
3716 bs_entry->state.shared_perm = 0;
3719 * If keep_old_opts is false then it means that unspecified
3720 * options must be reset to their original value. We don't allow
3721 * resetting 'backing' but we need to know if the option is
3722 * missing in order to decide if we have to return an error.
3724 if (!keep_old_opts) {
3725 bs_entry->state.backing_missing =
3726 !qdict_haskey(options, "backing") &&
3727 !qdict_haskey(options, "backing.driver");
3730 QLIST_FOREACH(child, &bs->children, next) {
3731 QDict *new_child_options = NULL;
3732 bool child_keep_old = keep_old_opts;
3734 /* reopen can only change the options of block devices that were
3735 * implicitly created and inherited options. For other (referenced)
3736 * block devices, a syntax like "backing.foo" results in an error. */
3737 if (child->bs->inherits_from != bs) {
3741 /* Check if the options contain a child reference */
3742 if (qdict_haskey(options, child->name)) {
3743 const char *childref = qdict_get_try_str(options, child->name);
3745 * The current child must not be reopened if the child
3746 * reference is null or points to a different node.
3748 if (g_strcmp0(childref, child->bs->node_name)) {
3752 * If the child reference points to the current child then
3753 * reopen it with its existing set of options (note that
3754 * it can still inherit new options from the parent).
3756 child_keep_old = true;
3758 /* Extract child options ("child-name.*") */
3759 char *child_key_dot = g_strdup_printf("%s.", child->name);
3760 qdict_extract_subqdict(explicit_options, NULL, child_key_dot);
3761 qdict_extract_subqdict(options, &new_child_options, child_key_dot);
3762 g_free(child_key_dot);
3765 bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options,
3766 child->klass, child->role, bs->drv->is_format,
3767 options, flags, child_keep_old);
3773 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
3774 BlockDriverState *bs,
3775 QDict *options, bool keep_old_opts)
3777 return bdrv_reopen_queue_child(bs_queue, bs, options, NULL, 0, false,
3778 NULL, 0, keep_old_opts);
3782 * Reopen multiple BlockDriverStates atomically & transactionally.
3784 * The queue passed in (bs_queue) must have been built up previous
3785 * via bdrv_reopen_queue().
3787 * Reopens all BDS specified in the queue, with the appropriate
3788 * flags. All devices are prepared for reopen, and failure of any
3789 * device will cause all device changes to be abandoned, and intermediate
3792 * If all devices prepare successfully, then the changes are committed
3795 * All affected nodes must be drained between bdrv_reopen_queue() and
3796 * bdrv_reopen_multiple().
3798 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
3801 BlockReopenQueueEntry *bs_entry, *next;
3803 assert(bs_queue != NULL);
3805 QTAILQ_FOREACH(bs_entry, bs_queue, entry) {
3806 assert(bs_entry->state.bs->quiesce_counter > 0);
3807 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, errp)) {
3810 bs_entry->prepared = true;
3813 QTAILQ_FOREACH(bs_entry, bs_queue, entry) {
3814 BDRVReopenState *state = &bs_entry->state;
3815 ret = bdrv_check_perm(state->bs, bs_queue, state->perm,
3816 state->shared_perm, NULL, NULL, errp);
3820 /* Check if new_backing_bs would accept the new permissions */
3821 if (state->replace_backing_bs && state->new_backing_bs) {
3822 uint64_t nperm, nshared;
3823 bdrv_child_perm(state->bs, state->new_backing_bs,
3824 NULL, bdrv_backing_role(state->bs),
3825 bs_queue, state->perm, state->shared_perm,
3827 ret = bdrv_check_update_perm(state->new_backing_bs, NULL,
3828 nperm, nshared, NULL, NULL, errp);
3833 bs_entry->perms_checked = true;
3837 * If we reach this point, we have success and just need to apply the
3840 * Reverse order is used to comfort qcow2 driver: on commit it need to write
3841 * IN_USE flag to the image, to mark bitmaps in the image as invalid. But
3842 * children are usually goes after parents in reopen-queue, so go from last
3845 QTAILQ_FOREACH_REVERSE(bs_entry, bs_queue, entry) {
3846 bdrv_reopen_commit(&bs_entry->state);
3851 QTAILQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
3852 BDRVReopenState *state = &bs_entry->state;
3854 if (!bs_entry->perms_checked) {
3859 bdrv_set_perm(state->bs, state->perm, state->shared_perm);
3861 bdrv_abort_perm_update(state->bs);
3862 if (state->replace_backing_bs && state->new_backing_bs) {
3863 bdrv_abort_perm_update(state->new_backing_bs);
3869 QTAILQ_FOREACH_REVERSE(bs_entry, bs_queue, entry) {
3870 BlockDriverState *bs = bs_entry->state.bs;
3872 if (bs->drv->bdrv_reopen_commit_post)
3873 bs->drv->bdrv_reopen_commit_post(&bs_entry->state);
3877 QTAILQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
3879 if (bs_entry->prepared) {
3880 bdrv_reopen_abort(&bs_entry->state);
3882 qobject_unref(bs_entry->state.explicit_options);
3883 qobject_unref(bs_entry->state.options);
3885 if (bs_entry->state.new_backing_bs) {
3886 bdrv_unref(bs_entry->state.new_backing_bs);
3895 int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
3899 BlockReopenQueue *queue;
3900 QDict *opts = qdict_new();
3902 qdict_put_bool(opts, BDRV_OPT_READ_ONLY, read_only);
3904 bdrv_subtree_drained_begin(bs);
3905 queue = bdrv_reopen_queue(NULL, bs, opts, true);
3906 ret = bdrv_reopen_multiple(queue, errp);
3907 bdrv_subtree_drained_end(bs);
3912 static BlockReopenQueueEntry *find_parent_in_reopen_queue(BlockReopenQueue *q,
3915 BlockReopenQueueEntry *entry;
3917 QTAILQ_FOREACH(entry, q, entry) {
3918 BlockDriverState *bs = entry->state.bs;
3921 QLIST_FOREACH(child, &bs->children, next) {
3931 static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs,
3932 uint64_t *perm, uint64_t *shared)
3935 BlockReopenQueueEntry *parent;
3936 uint64_t cumulative_perms = 0;
3937 uint64_t cumulative_shared_perms = BLK_PERM_ALL;
3939 QLIST_FOREACH(c, &bs->parents, next_parent) {
3940 parent = find_parent_in_reopen_queue(q, c);
3942 cumulative_perms |= c->perm;
3943 cumulative_shared_perms &= c->shared_perm;
3945 uint64_t nperm, nshared;
3947 bdrv_child_perm(parent->state.bs, bs, c, c->role, q,
3948 parent->state.perm, parent->state.shared_perm,
3951 cumulative_perms |= nperm;
3952 cumulative_shared_perms &= nshared;
3955 *perm = cumulative_perms;
3956 *shared = cumulative_shared_perms;
3959 static bool bdrv_reopen_can_attach(BlockDriverState *parent,
3961 BlockDriverState *new_child,
3964 AioContext *parent_ctx = bdrv_get_aio_context(parent);
3965 AioContext *child_ctx = bdrv_get_aio_context(new_child);
3969 ignore = g_slist_prepend(NULL, child);
3970 ret = bdrv_can_set_aio_context(new_child, parent_ctx, &ignore, NULL);
3971 g_slist_free(ignore);
3976 ignore = g_slist_prepend(NULL, child);
3977 ret = bdrv_can_set_aio_context(parent, child_ctx, &ignore, errp);
3978 g_slist_free(ignore);
3983 * Take a BDRVReopenState and check if the value of 'backing' in the
3984 * reopen_state->options QDict is valid or not.
3986 * If 'backing' is missing from the QDict then return 0.
3988 * If 'backing' contains the node name of the backing file of
3989 * reopen_state->bs then return 0.
3991 * If 'backing' contains a different node name (or is null) then check
3992 * whether the current backing file can be replaced with the new one.
3993 * If that's the case then reopen_state->replace_backing_bs is set to
3994 * true and reopen_state->new_backing_bs contains a pointer to the new
3995 * backing BlockDriverState (or NULL).
3997 * Return 0 on success, otherwise return < 0 and set @errp.
3999 static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state,
4002 BlockDriverState *bs = reopen_state->bs;
4003 BlockDriverState *overlay_bs, *below_bs, *new_backing_bs;
4007 value = qdict_get(reopen_state->options, "backing");
4008 if (value == NULL) {
4012 switch (qobject_type(value)) {
4014 new_backing_bs = NULL;
4017 str = qobject_get_try_str(value);
4018 new_backing_bs = bdrv_lookup_bs(NULL, str, errp);
4019 if (new_backing_bs == NULL) {
4021 } else if (bdrv_recurse_has_child(new_backing_bs, bs)) {
4022 error_setg(errp, "Making '%s' a backing file of '%s' "
4023 "would create a cycle", str, bs->node_name);
4028 /* 'backing' does not allow any other data type */
4029 g_assert_not_reached();
4033 * Check AioContext compatibility so that the bdrv_set_backing_hd() call in
4034 * bdrv_reopen_commit() won't fail.
4036 if (new_backing_bs) {
4037 if (!bdrv_reopen_can_attach(bs, bs->backing, new_backing_bs, errp)) {
4043 * Ensure that @bs can really handle backing files, because we are
4044 * about to give it one (or swap the existing one)
4046 if (bs->drv->is_filter) {
4047 /* Filters always have a file or a backing child */
4049 error_setg(errp, "'%s' is a %s filter node that does not support a "
4050 "backing child", bs->node_name, bs->drv->format_name);
4053 } else if (!bs->drv->supports_backing) {
4054 error_setg(errp, "Driver '%s' of node '%s' does not support backing "
4055 "files", bs->drv->format_name, bs->node_name);
4060 * Find the "actual" backing file by skipping all links that point
4061 * to an implicit node, if any (e.g. a commit filter node).
4062 * We cannot use any of the bdrv_skip_*() functions here because
4063 * those return the first explicit node, while we are looking for
4067 for (below_bs = bdrv_filter_or_cow_bs(overlay_bs);
4068 below_bs && below_bs->implicit;
4069 below_bs = bdrv_filter_or_cow_bs(overlay_bs))
4071 overlay_bs = below_bs;
4074 /* If we want to replace the backing file we need some extra checks */
4075 if (new_backing_bs != bdrv_filter_or_cow_bs(overlay_bs)) {
4076 /* Check for implicit nodes between bs and its backing file */
4077 if (bs != overlay_bs) {
4078 error_setg(errp, "Cannot change backing link if '%s' has "
4079 "an implicit backing file", bs->node_name);
4083 * Check if the backing link that we want to replace is frozen.
4085 * bdrv_filter_or_cow_child(overlay_bs) == overlay_bs->backing,
4086 * because we know that overlay_bs == bs, and that @bs
4087 * either is a filter that uses ->backing or a COW format BDS
4088 * with bs->drv->supports_backing == true.
4090 if (bdrv_is_backing_chain_frozen(overlay_bs,
4091 child_bs(overlay_bs->backing), errp))
4095 reopen_state->replace_backing_bs = true;
4096 if (new_backing_bs) {
4097 bdrv_ref(new_backing_bs);
4098 reopen_state->new_backing_bs = new_backing_bs;
4106 * Prepares a BlockDriverState for reopen. All changes are staged in the
4107 * 'opaque' field of the BDRVReopenState, which is used and allocated by
4108 * the block driver layer .bdrv_reopen_prepare()
4110 * bs is the BlockDriverState to reopen
4111 * flags are the new open flags
4112 * queue is the reopen queue
4114 * Returns 0 on success, non-zero on error. On error errp will be set
4117 * On failure, bdrv_reopen_abort() will be called to clean up any data.
4118 * It is the responsibility of the caller to then call the abort() or
4119 * commit() for any other BDS that have been left in a prepare() state
4122 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
4127 Error *local_err = NULL;
4130 QDict *orig_reopen_opts;
4131 char *discard = NULL;
4133 bool drv_prepared = false;
4135 assert(reopen_state != NULL);
4136 assert(reopen_state->bs->drv != NULL);
4137 drv = reopen_state->bs->drv;
4139 /* This function and each driver's bdrv_reopen_prepare() remove
4140 * entries from reopen_state->options as they are processed, so
4141 * we need to make a copy of the original QDict. */
4142 orig_reopen_opts = qdict_clone_shallow(reopen_state->options);
4144 /* Process generic block layer options */
4145 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
4146 if (!qemu_opts_absorb_qdict(opts, reopen_state->options, errp)) {
4151 /* This was already called in bdrv_reopen_queue_child() so the flags
4152 * are up-to-date. This time we simply want to remove the options from
4153 * QemuOpts in order to indicate that they have been processed. */
4154 old_flags = reopen_state->flags;
4155 update_flags_from_options(&reopen_state->flags, opts);
4156 assert(old_flags == reopen_state->flags);
4158 discard = qemu_opt_get_del(opts, BDRV_OPT_DISCARD);
4159 if (discard != NULL) {
4160 if (bdrv_parse_discard_flags(discard, &reopen_state->flags) != 0) {
4161 error_setg(errp, "Invalid discard option");
4167 reopen_state->detect_zeroes =
4168 bdrv_parse_detect_zeroes(opts, reopen_state->flags, &local_err);
4170 error_propagate(errp, local_err);
4175 /* All other options (including node-name and driver) must be unchanged.
4176 * Put them back into the QDict, so that they are checked at the end
4177 * of this function. */
4178 qemu_opts_to_qdict(opts, reopen_state->options);
4180 /* If we are to stay read-only, do not allow permission change
4181 * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is
4182 * not set, or if the BDS still has copy_on_read enabled */
4183 read_only = !(reopen_state->flags & BDRV_O_RDWR);
4184 ret = bdrv_can_set_read_only(reopen_state->bs, read_only, true, &local_err);
4186 error_propagate(errp, local_err);
4190 /* Calculate required permissions after reopening */
4191 bdrv_reopen_perm(queue, reopen_state->bs,
4192 &reopen_state->perm, &reopen_state->shared_perm);
4194 ret = bdrv_flush(reopen_state->bs);
4196 error_setg_errno(errp, -ret, "Error flushing drive");
4200 if (drv->bdrv_reopen_prepare) {
4202 * If a driver-specific option is missing, it means that we
4203 * should reset it to its default value.
4204 * But not all options allow that, so we need to check it first.
4206 ret = bdrv_reset_options_allowed(reopen_state->bs,
4207 reopen_state->options, errp);
4212 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err);
4214 if (local_err != NULL) {
4215 error_propagate(errp, local_err);
4217 bdrv_refresh_filename(reopen_state->bs);
4218 error_setg(errp, "failed while preparing to reopen image '%s'",
4219 reopen_state->bs->filename);
4224 /* It is currently mandatory to have a bdrv_reopen_prepare()
4225 * handler for each supported drv. */
4226 error_setg(errp, "Block format '%s' used by node '%s' "
4227 "does not support reopening files", drv->format_name,
4228 bdrv_get_device_or_node_name(reopen_state->bs));
4233 drv_prepared = true;
4236 * We must provide the 'backing' option if the BDS has a backing
4237 * file or if the image file has a backing file name as part of
4238 * its metadata. Otherwise the 'backing' option can be omitted.
4240 if (drv->supports_backing && reopen_state->backing_missing &&
4241 (reopen_state->bs->backing || reopen_state->bs->backing_file[0])) {
4242 error_setg(errp, "backing is missing for '%s'",
4243 reopen_state->bs->node_name);
4249 * Allow changing the 'backing' option. The new value can be
4250 * either a reference to an existing node (using its node name)
4251 * or NULL to simply detach the current backing file.
4253 ret = bdrv_reopen_parse_backing(reopen_state, errp);
4257 qdict_del(reopen_state->options, "backing");
4259 /* Options that are not handled are only okay if they are unchanged
4260 * compared to the old state. It is expected that some options are only
4261 * used for the initial open, but not reopen (e.g. filename) */
4262 if (qdict_size(reopen_state->options)) {
4263 const QDictEntry *entry = qdict_first(reopen_state->options);
4266 QObject *new = entry->value;
4267 QObject *old = qdict_get(reopen_state->bs->options, entry->key);
4269 /* Allow child references (child_name=node_name) as long as they
4270 * point to the current child (i.e. everything stays the same). */
4271 if (qobject_type(new) == QTYPE_QSTRING) {
4273 QLIST_FOREACH(child, &reopen_state->bs->children, next) {
4274 if (!strcmp(child->name, entry->key)) {
4280 const char *str = qobject_get_try_str(new);
4281 if (!strcmp(child->bs->node_name, str)) {
4282 continue; /* Found child with this name, skip option */
4288 * TODO: When using -drive to specify blockdev options, all values
4289 * will be strings; however, when using -blockdev, blockdev-add or
4290 * filenames using the json:{} pseudo-protocol, they will be
4292 * In contrast, reopening options are (currently) always strings
4293 * (because you can only specify them through qemu-io; all other
4294 * callers do not specify any options).
4295 * Therefore, when using anything other than -drive to create a BDS,
4296 * this cannot detect non-string options as unchanged, because
4297 * qobject_is_equal() always returns false for objects of different
4298 * type. In the future, this should be remedied by correctly typing
4299 * all options. For now, this is not too big of an issue because
4300 * the user can simply omit options which cannot be changed anyway,
4301 * so they will stay unchanged.
4303 if (!qobject_is_equal(new, old)) {
4304 error_setg(errp, "Cannot change the option '%s'", entry->key);
4308 } while ((entry = qdict_next(reopen_state->options, entry)));
4313 /* Restore the original reopen_state->options QDict */
4314 qobject_unref(reopen_state->options);
4315 reopen_state->options = qobject_ref(orig_reopen_opts);
4318 if (ret < 0 && drv_prepared) {
4319 /* drv->bdrv_reopen_prepare() has succeeded, so we need to
4320 * call drv->bdrv_reopen_abort() before signaling an error
4321 * (bdrv_reopen_multiple() will not call bdrv_reopen_abort()
4322 * when the respective bdrv_reopen_prepare() has failed) */
4323 if (drv->bdrv_reopen_abort) {
4324 drv->bdrv_reopen_abort(reopen_state);
4327 qemu_opts_del(opts);
4328 qobject_unref(orig_reopen_opts);
4334 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
4335 * makes them final by swapping the staging BlockDriverState contents into
4336 * the active BlockDriverState contents.
4338 void bdrv_reopen_commit(BDRVReopenState *reopen_state)
4341 BlockDriverState *bs;
4344 assert(reopen_state != NULL);
4345 bs = reopen_state->bs;
4347 assert(drv != NULL);
4349 /* If there are any driver level actions to take */
4350 if (drv->bdrv_reopen_commit) {
4351 drv->bdrv_reopen_commit(reopen_state);
4354 /* set BDS specific flags now */
4355 qobject_unref(bs->explicit_options);
4356 qobject_unref(bs->options);
4358 bs->explicit_options = reopen_state->explicit_options;
4359 bs->options = reopen_state->options;
4360 bs->open_flags = reopen_state->flags;
4361 bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
4362 bs->detect_zeroes = reopen_state->detect_zeroes;
4364 if (reopen_state->replace_backing_bs) {
4365 qdict_del(bs->explicit_options, "backing");
4366 qdict_del(bs->options, "backing");
4369 /* Remove child references from bs->options and bs->explicit_options.
4370 * Child options were already removed in bdrv_reopen_queue_child() */
4371 QLIST_FOREACH(child, &bs->children, next) {
4372 qdict_del(bs->explicit_options, child->name);
4373 qdict_del(bs->options, child->name);
4377 * Change the backing file if a new one was specified. We do this
4378 * after updating bs->options, so bdrv_refresh_filename() (called
4379 * from bdrv_set_backing_hd()) has the new values.
4381 if (reopen_state->replace_backing_bs) {
4382 BlockDriverState *old_backing_bs = child_bs(bs->backing);
4383 assert(!old_backing_bs || !old_backing_bs->implicit);
4384 /* Abort the permission update on the backing bs we're detaching */
4385 if (old_backing_bs) {
4386 bdrv_abort_perm_update(old_backing_bs);
4388 bdrv_set_backing_hd(bs, reopen_state->new_backing_bs, &error_abort);
4391 bdrv_refresh_limits(bs, NULL);
4395 * Abort the reopen, and delete and free the staged changes in
4398 void bdrv_reopen_abort(BDRVReopenState *reopen_state)
4402 assert(reopen_state != NULL);
4403 drv = reopen_state->bs->drv;
4404 assert(drv != NULL);
4406 if (drv->bdrv_reopen_abort) {
4407 drv->bdrv_reopen_abort(reopen_state);
4412 static void bdrv_close(BlockDriverState *bs)
4414 BdrvAioNotifier *ban, *ban_next;
4415 BdrvChild *child, *next;
4417 assert(!bs->refcnt);
4419 bdrv_drained_begin(bs); /* complete I/O */
4421 bdrv_drain(bs); /* in case flush left pending I/O */
4424 if (bs->drv->bdrv_close) {
4425 /* Must unfreeze all children, so bdrv_unref_child() works */
4426 bs->drv->bdrv_close(bs);
4431 QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
4432 bdrv_unref_child(bs, child);
4439 atomic_set(&bs->copy_on_read, 0);
4440 bs->backing_file[0] = '\0';
4441 bs->backing_format[0] = '\0';
4442 bs->total_sectors = 0;
4443 bs->encrypted = false;
4445 qobject_unref(bs->options);
4446 qobject_unref(bs->explicit_options);
4448 bs->explicit_options = NULL;
4449 qobject_unref(bs->full_open_options);
4450 bs->full_open_options = NULL;
4452 bdrv_release_named_dirty_bitmaps(bs);
4453 assert(QLIST_EMPTY(&bs->dirty_bitmaps));
4455 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
4458 QLIST_INIT(&bs->aio_notifiers);
4459 bdrv_drained_end(bs);
4462 void bdrv_close_all(void)
4464 assert(job_next(NULL) == NULL);
4465 nbd_export_close_all();
4467 /* Drop references from requests still in flight, such as canceled block
4468 * jobs whose AIO context has not been polled yet */
4471 blk_remove_all_bs();
4472 blockdev_close_all_bdrv_states();
4474 assert(QTAILQ_EMPTY(&all_bdrv_states));
4477 static bool should_update_child(BdrvChild *c, BlockDriverState *to)
4483 if (c->klass->stay_at_node) {
4487 /* If the child @c belongs to the BDS @to, replacing the current
4488 * c->bs by @to would mean to create a loop.
4490 * Such a case occurs when appending a BDS to a backing chain.
4491 * For instance, imagine the following chain:
4493 * guest device -> node A -> further backing chain...
4495 * Now we create a new BDS B which we want to put on top of this
4496 * chain, so we first attach A as its backing node:
4501 * guest device -> node A -> further backing chain...
4503 * Finally we want to replace A by B. When doing that, we want to
4504 * replace all pointers to A by pointers to B -- except for the
4505 * pointer from B because (1) that would create a loop, and (2)
4506 * that pointer should simply stay intact:
4508 * guest device -> node B
4511 * node A -> further backing chain...
4513 * In general, when replacing a node A (c->bs) by a node B (@to),
4514 * if A is a child of B, that means we cannot replace A by B there
4515 * because that would create a loop. Silently detaching A from B
4516 * is also not really an option. So overall just leaving A in
4517 * place there is the most sensible choice.
4519 * We would also create a loop in any cases where @c is only
4520 * indirectly referenced by @to. Prevent this by returning false
4521 * if @c is found (by breadth-first search) anywhere in the whole
4526 found = g_hash_table_new(NULL, NULL);
4527 g_hash_table_add(found, to);
4528 queue = g_queue_new();
4529 g_queue_push_tail(queue, to);
4531 while (!g_queue_is_empty(queue)) {
4532 BlockDriverState *v = g_queue_pop_head(queue);
4535 QLIST_FOREACH(c2, &v->children, next) {
4541 if (g_hash_table_contains(found, c2->bs)) {
4545 g_queue_push_tail(queue, c2->bs);
4546 g_hash_table_add(found, c2->bs);
4550 g_queue_free(queue);
4551 g_hash_table_destroy(found);
4556 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
4559 BdrvChild *c, *next;
4560 GSList *list = NULL, *p;
4561 uint64_t perm = 0, shared = BLK_PERM_ALL;
4564 /* Make sure that @from doesn't go away until we have successfully attached
4565 * all of its parents to @to. */
4568 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
4569 assert(bdrv_get_aio_context(from) == bdrv_get_aio_context(to));
4570 bdrv_drained_begin(from);
4572 /* Put all parents into @list and calculate their cumulative permissions */
4573 QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
4574 assert(c->bs == from);
4575 if (!should_update_child(c, to)) {
4579 error_setg(errp, "Cannot change '%s' link to '%s'",
4580 c->name, from->node_name);
4583 list = g_slist_prepend(list, c);
4585 shared &= c->shared_perm;
4588 /* Check whether the required permissions can be granted on @to, ignoring
4589 * all BdrvChild in @list so that they can't block themselves. */
4590 ret = bdrv_check_update_perm(to, NULL, perm, shared, list, NULL, errp);
4592 bdrv_abort_perm_update(to);
4596 /* Now actually perform the change. We performed the permission check for
4597 * all elements of @list at once, so set the permissions all at once at the
4599 for (p = list; p != NULL; p = p->next) {
4603 bdrv_replace_child_noperm(c, to);
4607 bdrv_get_cumulative_perm(to, &perm, &shared);
4608 bdrv_set_perm(to, perm, shared);
4612 bdrv_drained_end(from);
4617 * Add new bs contents at the top of an image chain while the chain is
4618 * live, while keeping required fields on the top layer.
4620 * This will modify the BlockDriverState fields, and swap contents
4621 * between bs_new and bs_top. Both bs_new and bs_top are modified.
4623 * bs_new must not be attached to a BlockBackend.
4625 * This function does not create any image files.
4627 * bdrv_append() takes ownership of a bs_new reference and unrefs it because
4628 * that's what the callers commonly need. bs_new will be referenced by the old
4629 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a
4630 * reference of its own, it must call bdrv_ref().
4632 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
4635 Error *local_err = NULL;
4637 bdrv_set_backing_hd(bs_new, bs_top, &local_err);
4639 error_propagate(errp, local_err);
4643 bdrv_replace_node(bs_top, bs_new, &local_err);
4645 error_propagate(errp, local_err);
4646 bdrv_set_backing_hd(bs_new, NULL, &error_abort);
4650 /* bs_new is now referenced by its new parents, we don't need the
4651 * additional reference any more. */
4656 static void bdrv_delete(BlockDriverState *bs)
4658 assert(bdrv_op_blocker_is_empty(bs));
4659 assert(!bs->refcnt);
4661 /* remove from list, if necessary */
4662 if (bs->node_name[0] != '\0') {
4663 QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list);
4665 QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list);
4673 * Run consistency checks on an image
4675 * Returns 0 if the check could be completed (it doesn't mean that the image is
4676 * free of errors) or -errno when an internal error occurred. The results of the
4677 * check are stored in res.
4679 static int coroutine_fn bdrv_co_check(BlockDriverState *bs,
4680 BdrvCheckResult *res, BdrvCheckMode fix)
4682 if (bs->drv == NULL) {
4685 if (bs->drv->bdrv_co_check == NULL) {
4689 memset(res, 0, sizeof(*res));
4690 return bs->drv->bdrv_co_check(bs, res, fix);
4693 typedef struct CheckCo {
4694 BlockDriverState *bs;
4695 BdrvCheckResult *res;
4700 static void coroutine_fn bdrv_check_co_entry(void *opaque)
4702 CheckCo *cco = opaque;
4703 cco->ret = bdrv_co_check(cco->bs, cco->res, cco->fix);
4707 int bdrv_check(BlockDriverState *bs,
4708 BdrvCheckResult *res, BdrvCheckMode fix)
4714 .ret = -EINPROGRESS,
4718 if (qemu_in_coroutine()) {
4719 /* Fast-path if already in coroutine context */
4720 bdrv_check_co_entry(&cco);
4722 co = qemu_coroutine_create(bdrv_check_co_entry, &cco);
4723 bdrv_coroutine_enter(bs, co);
4724 BDRV_POLL_WHILE(bs, cco.ret == -EINPROGRESS);
4733 * -EINVAL - backing format specified, but no file
4734 * -ENOSPC - can't update the backing file because no space is left in the
4736 * -ENOTSUP - format driver doesn't support changing the backing file
4738 int bdrv_change_backing_file(BlockDriverState *bs, const char *backing_file,
4739 const char *backing_fmt, bool warn)
4741 BlockDriver *drv = bs->drv;
4748 /* Backing file format doesn't make sense without a backing file */
4749 if (backing_fmt && !backing_file) {
4753 if (warn && backing_file && !backing_fmt) {
4754 warn_report("Deprecated use of backing file without explicit "
4755 "backing format, use of this image requires "
4756 "potentially unsafe format probing");
4759 if (drv->bdrv_change_backing_file != NULL) {
4760 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
4766 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
4767 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
4768 pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file),
4769 backing_file ?: "");
4775 * Finds the first non-filter node above bs in the chain between
4776 * active and bs. The returned node is either an immediate parent of
4777 * bs, or there are only filter nodes between the two.
4779 * Returns NULL if bs is not found in active's image chain,
4780 * or if active == bs.
4782 * Returns the bottommost base image if bs == NULL.
4784 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
4785 BlockDriverState *bs)
4787 bs = bdrv_skip_filters(bs);
4788 active = bdrv_skip_filters(active);
4791 BlockDriverState *next = bdrv_backing_chain_next(active);
4801 /* Given a BDS, searches for the base layer. */
4802 BlockDriverState *bdrv_find_base(BlockDriverState *bs)
4804 return bdrv_find_overlay(bs, NULL);
4808 * Return true if at least one of the COW (backing) and filter links
4809 * between @bs and @base is frozen. @errp is set if that's the case.
4810 * @base must be reachable from @bs, or NULL.
4812 bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
4815 BlockDriverState *i;
4818 for (i = bs; i != base; i = child_bs(child)) {
4819 child = bdrv_filter_or_cow_child(i);
4821 if (child && child->frozen) {
4822 error_setg(errp, "Cannot change '%s' link from '%s' to '%s'",
4823 child->name, i->node_name, child->bs->node_name);
4832 * Freeze all COW (backing) and filter links between @bs and @base.
4833 * If any of the links is already frozen the operation is aborted and
4834 * none of the links are modified.
4835 * @base must be reachable from @bs, or NULL.
4836 * Returns 0 on success. On failure returns < 0 and sets @errp.
4838 int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
4841 BlockDriverState *i;
4844 if (bdrv_is_backing_chain_frozen(bs, base, errp)) {
4848 for (i = bs; i != base; i = child_bs(child)) {
4849 child = bdrv_filter_or_cow_child(i);
4850 if (child && child->bs->never_freeze) {
4851 error_setg(errp, "Cannot freeze '%s' link to '%s'",
4852 child->name, child->bs->node_name);
4857 for (i = bs; i != base; i = child_bs(child)) {
4858 child = bdrv_filter_or_cow_child(i);
4860 child->frozen = true;
4868 * Unfreeze all COW (backing) and filter links between @bs and @base.
4869 * The caller must ensure that all links are frozen before using this
4871 * @base must be reachable from @bs, or NULL.
4873 void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base)
4875 BlockDriverState *i;
4878 for (i = bs; i != base; i = child_bs(child)) {
4879 child = bdrv_filter_or_cow_child(i);
4881 assert(child->frozen);
4882 child->frozen = false;
4888 * Drops images above 'base' up to and including 'top', and sets the image
4889 * above 'top' to have base as its backing file.
4891 * Requires that the overlay to 'top' is opened r/w, so that the backing file
4892 * information in 'bs' can be properly updated.
4894 * E.g., this will convert the following chain:
4895 * bottom <- base <- intermediate <- top <- active
4899 * bottom <- base <- active
4901 * It is allowed for bottom==base, in which case it converts:
4903 * base <- intermediate <- top <- active
4909 * If backing_file_str is non-NULL, it will be used when modifying top's
4910 * overlay image metadata.
4913 * if active == top, that is considered an error
4916 int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
4917 const char *backing_file_str)
4919 BlockDriverState *explicit_top = top;
4920 bool update_inherits_from;
4921 BdrvChild *c, *next;
4922 Error *local_err = NULL;
4926 bdrv_subtree_drained_begin(top);
4928 if (!top->drv || !base->drv) {
4932 /* Make sure that base is in the backing chain of top */
4933 if (!bdrv_chain_contains(top, base)) {
4937 /* This function changes all links that point to top and makes
4938 * them point to base. Check that none of them is frozen. */
4939 QLIST_FOREACH(c, &top->parents, next_parent) {
4945 /* If 'base' recursively inherits from 'top' then we should set
4946 * base->inherits_from to top->inherits_from after 'top' and all
4947 * other intermediate nodes have been dropped.
4948 * If 'top' is an implicit node (e.g. "commit_top") we should skip
4949 * it because no one inherits from it. We use explicit_top for that. */
4950 explicit_top = bdrv_skip_implicit_filters(explicit_top);
4951 update_inherits_from = bdrv_inherits_from_recursive(base, explicit_top);
4953 /* success - we can delete the intermediate states, and link top->base */
4954 /* TODO Check graph modification op blockers (BLK_PERM_GRAPH_MOD) once
4955 * we've figured out how they should work. */
4956 if (!backing_file_str) {
4957 bdrv_refresh_filename(base);
4958 backing_file_str = base->filename;
4961 QLIST_FOREACH_SAFE(c, &top->parents, next_parent, next) {
4962 /* Check whether we are allowed to switch c from top to base */
4963 GSList *ignore_children = g_slist_prepend(NULL, c);
4964 ret = bdrv_check_update_perm(base, NULL, c->perm, c->shared_perm,
4965 ignore_children, NULL, &local_err);
4966 g_slist_free(ignore_children);
4968 error_report_err(local_err);
4972 /* If so, update the backing file path in the image file */
4973 if (c->klass->update_filename) {
4974 ret = c->klass->update_filename(c, base, backing_file_str,
4977 bdrv_abort_perm_update(base);
4978 error_report_err(local_err);
4984 * Do the actual switch in the in-memory graph.
4985 * Completes bdrv_check_update_perm() transaction internally.
4986 * c->frozen is false, we have checked that above.
4989 bdrv_replace_child(c, base);
4993 if (update_inherits_from) {
4994 base->inherits_from = explicit_top->inherits_from;
4999 bdrv_subtree_drained_end(top);
5005 * Implementation of BlockDriver.bdrv_get_allocated_file_size() that
5006 * sums the size of all data-bearing children. (This excludes backing
5009 static int64_t bdrv_sum_allocated_file_size(BlockDriverState *bs)
5012 int64_t child_size, sum = 0;
5014 QLIST_FOREACH(child, &bs->children, next) {
5015 if (child->role & (BDRV_CHILD_DATA | BDRV_CHILD_METADATA |
5016 BDRV_CHILD_FILTERED))
5018 child_size = bdrv_get_allocated_file_size(child->bs);
5019 if (child_size < 0) {
5030 * Length of a allocated file in bytes. Sparse files are counted by actual
5031 * allocated space. Return < 0 if error or unknown.
5033 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs)
5035 BlockDriver *drv = bs->drv;
5039 if (drv->bdrv_get_allocated_file_size) {
5040 return drv->bdrv_get_allocated_file_size(bs);
5043 if (drv->bdrv_file_open) {
5045 * Protocol drivers default to -ENOTSUP (most of their data is
5046 * not stored in any of their children (if they even have any),
5047 * so there is no generic way to figure it out).
5050 } else if (drv->is_filter) {
5051 /* Filter drivers default to the size of their filtered child */
5052 return bdrv_get_allocated_file_size(bdrv_filter_bs(bs));
5054 /* Other drivers default to summing their children's sizes */
5055 return bdrv_sum_allocated_file_size(bs);
5061 * @drv: Format driver
5062 * @opts: Creation options for new image
5063 * @in_bs: Existing image containing data for new image (may be NULL)
5064 * @errp: Error object
5065 * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo())
5068 * Calculate file size required to create a new image.
5070 * If @in_bs is given then space for allocated clusters and zero clusters
5071 * from that image are included in the calculation. If @opts contains a
5072 * backing file that is shared by @in_bs then backing clusters may be omitted
5073 * from the calculation.
5075 * If @in_bs is NULL then the calculation includes no allocated clusters
5076 * unless a preallocation option is given in @opts.
5078 * Note that @in_bs may use a different BlockDriver from @drv.
5080 * If an error occurs the @errp pointer is set.
5082 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
5083 BlockDriverState *in_bs, Error **errp)
5085 if (!drv->bdrv_measure) {
5086 error_setg(errp, "Block driver '%s' does not support size measurement",
5091 return drv->bdrv_measure(opts, in_bs, errp);
5095 * Return number of sectors on success, -errno on error.
5097 int64_t bdrv_nb_sectors(BlockDriverState *bs)
5099 BlockDriver *drv = bs->drv;
5104 if (drv->has_variable_length) {
5105 int ret = refresh_total_sectors(bs, bs->total_sectors);
5110 return bs->total_sectors;
5114 * Return length in bytes on success, -errno on error.
5115 * The length is always a multiple of BDRV_SECTOR_SIZE.
5117 int64_t bdrv_getlength(BlockDriverState *bs)
5119 int64_t ret = bdrv_nb_sectors(bs);
5121 ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret;
5122 return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE;
5125 /* return 0 as number of sectors if no device present or error */
5126 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
5128 int64_t nb_sectors = bdrv_nb_sectors(bs);
5130 *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors;
5133 bool bdrv_is_sg(BlockDriverState *bs)
5139 * Return whether the given node supports compressed writes.
5141 bool bdrv_supports_compressed_writes(BlockDriverState *bs)
5143 BlockDriverState *filtered;
5145 if (!bs->drv || !block_driver_can_compress(bs->drv)) {
5149 filtered = bdrv_filter_bs(bs);
5152 * Filters can only forward compressed writes, so we have to
5155 return bdrv_supports_compressed_writes(filtered);
5161 const char *bdrv_get_format_name(BlockDriverState *bs)
5163 return bs->drv ? bs->drv->format_name : NULL;
5166 static int qsort_strcmp(const void *a, const void *b)
5168 return strcmp(*(char *const *)a, *(char *const *)b);
5171 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
5172 void *opaque, bool read_only)
5177 const char **formats = NULL;
5179 QLIST_FOREACH(drv, &bdrv_drivers, list) {
5180 if (drv->format_name) {
5184 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, read_only)) {
5188 while (formats && i && !found) {
5189 found = !strcmp(formats[--i], drv->format_name);
5193 formats = g_renew(const char *, formats, count + 1);
5194 formats[count++] = drv->format_name;
5199 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); i++) {
5200 const char *format_name = block_driver_modules[i].format_name;
5206 if (use_bdrv_whitelist &&
5207 !bdrv_format_is_whitelisted(format_name, read_only)) {
5211 while (formats && j && !found) {
5212 found = !strcmp(formats[--j], format_name);
5216 formats = g_renew(const char *, formats, count + 1);
5217 formats[count++] = format_name;
5222 qsort(formats, count, sizeof(formats[0]), qsort_strcmp);
5224 for (i = 0; i < count; i++) {
5225 it(opaque, formats[i]);
5231 /* This function is to find a node in the bs graph */
5232 BlockDriverState *bdrv_find_node(const char *node_name)
5234 BlockDriverState *bs;
5238 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
5239 if (!strcmp(node_name, bs->node_name)) {
5246 /* Put this QMP function here so it can access the static graph_bdrv_states. */
5247 BlockDeviceInfoList *bdrv_named_nodes_list(bool flat,
5250 BlockDeviceInfoList *list, *entry;
5251 BlockDriverState *bs;
5254 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
5255 BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, flat, errp);
5257 qapi_free_BlockDeviceInfoList(list);
5260 entry = g_malloc0(sizeof(*entry));
5261 entry->value = info;
5269 #define QAPI_LIST_ADD(list, element) do { \
5270 typeof(list) _tmp = g_new(typeof(*(list)), 1); \
5271 _tmp->value = (element); \
5272 _tmp->next = (list); \
5276 typedef struct XDbgBlockGraphConstructor {
5277 XDbgBlockGraph *graph;
5278 GHashTable *graph_nodes;
5279 } XDbgBlockGraphConstructor;
5281 static XDbgBlockGraphConstructor *xdbg_graph_new(void)
5283 XDbgBlockGraphConstructor *gr = g_new(XDbgBlockGraphConstructor, 1);
5285 gr->graph = g_new0(XDbgBlockGraph, 1);
5286 gr->graph_nodes = g_hash_table_new(NULL, NULL);
5291 static XDbgBlockGraph *xdbg_graph_finalize(XDbgBlockGraphConstructor *gr)
5293 XDbgBlockGraph *graph = gr->graph;
5295 g_hash_table_destroy(gr->graph_nodes);
5301 static uintptr_t xdbg_graph_node_num(XDbgBlockGraphConstructor *gr, void *node)
5303 uintptr_t ret = (uintptr_t)g_hash_table_lookup(gr->graph_nodes, node);
5310 * Start counting from 1, not 0, because 0 interferes with not-found (NULL)
5311 * answer of g_hash_table_lookup.
5313 ret = g_hash_table_size(gr->graph_nodes) + 1;
5314 g_hash_table_insert(gr->graph_nodes, node, (void *)ret);
5319 static void xdbg_graph_add_node(XDbgBlockGraphConstructor *gr, void *node,
5320 XDbgBlockGraphNodeType type, const char *name)
5322 XDbgBlockGraphNode *n;
5324 n = g_new0(XDbgBlockGraphNode, 1);
5326 n->id = xdbg_graph_node_num(gr, node);
5328 n->name = g_strdup(name);
5330 QAPI_LIST_ADD(gr->graph->nodes, n);
5333 static void xdbg_graph_add_edge(XDbgBlockGraphConstructor *gr, void *parent,
5334 const BdrvChild *child)
5336 BlockPermission qapi_perm;
5337 XDbgBlockGraphEdge *edge;
5339 edge = g_new0(XDbgBlockGraphEdge, 1);
5341 edge->parent = xdbg_graph_node_num(gr, parent);
5342 edge->child = xdbg_graph_node_num(gr, child->bs);
5343 edge->name = g_strdup(child->name);
5345 for (qapi_perm = 0; qapi_perm < BLOCK_PERMISSION__MAX; qapi_perm++) {
5346 uint64_t flag = bdrv_qapi_perm_to_blk_perm(qapi_perm);
5348 if (flag & child->perm) {
5349 QAPI_LIST_ADD(edge->perm, qapi_perm);
5351 if (flag & child->shared_perm) {
5352 QAPI_LIST_ADD(edge->shared_perm, qapi_perm);
5356 QAPI_LIST_ADD(gr->graph->edges, edge);
5360 XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp)
5364 BlockDriverState *bs;
5366 XDbgBlockGraphConstructor *gr = xdbg_graph_new();
5368 for (blk = blk_all_next(NULL); blk; blk = blk_all_next(blk)) {
5369 char *allocated_name = NULL;
5370 const char *name = blk_name(blk);
5373 name = allocated_name = blk_get_attached_dev_id(blk);
5375 xdbg_graph_add_node(gr, blk, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND,
5377 g_free(allocated_name);
5378 if (blk_root(blk)) {
5379 xdbg_graph_add_edge(gr, blk, blk_root(blk));
5383 for (job = block_job_next(NULL); job; job = block_job_next(job)) {
5386 xdbg_graph_add_node(gr, job, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB,
5388 for (el = job->nodes; el; el = el->next) {
5389 xdbg_graph_add_edge(gr, job, (BdrvChild *)el->data);
5393 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
5394 xdbg_graph_add_node(gr, bs, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_DRIVER,
5396 QLIST_FOREACH(child, &bs->children, next) {
5397 xdbg_graph_add_edge(gr, bs, child);
5401 return xdbg_graph_finalize(gr);
5404 BlockDriverState *bdrv_lookup_bs(const char *device,
5405 const char *node_name,
5409 BlockDriverState *bs;
5412 blk = blk_by_name(device);
5417 error_setg(errp, "Device '%s' has no medium", device);
5425 bs = bdrv_find_node(node_name);
5432 error_setg(errp, "Cannot find device=%s nor node_name=%s",
5433 device ? device : "",
5434 node_name ? node_name : "");
5438 /* If 'base' is in the same chain as 'top', return true. Otherwise,
5439 * return false. If either argument is NULL, return false. */
5440 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base)
5442 while (top && top != base) {
5443 top = bdrv_filter_or_cow_bs(top);
5449 BlockDriverState *bdrv_next_node(BlockDriverState *bs)
5452 return QTAILQ_FIRST(&graph_bdrv_states);
5454 return QTAILQ_NEXT(bs, node_list);
5457 BlockDriverState *bdrv_next_all_states(BlockDriverState *bs)
5460 return QTAILQ_FIRST(&all_bdrv_states);
5462 return QTAILQ_NEXT(bs, bs_list);
5465 const char *bdrv_get_node_name(const BlockDriverState *bs)
5467 return bs->node_name;
5470 const char *bdrv_get_parent_name(const BlockDriverState *bs)
5475 /* If multiple parents have a name, just pick the first one. */
5476 QLIST_FOREACH(c, &bs->parents, next_parent) {
5477 if (c->klass->get_name) {
5478 name = c->klass->get_name(c);
5479 if (name && *name) {
5488 /* TODO check what callers really want: bs->node_name or blk_name() */
5489 const char *bdrv_get_device_name(const BlockDriverState *bs)
5491 return bdrv_get_parent_name(bs) ?: "";
5494 /* This can be used to identify nodes that might not have a device
5495 * name associated. Since node and device names live in the same
5496 * namespace, the result is unambiguous. The exception is if both are
5497 * absent, then this returns an empty (non-null) string. */
5498 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs)
5500 return bdrv_get_parent_name(bs) ?: bs->node_name;
5503 int bdrv_get_flags(BlockDriverState *bs)
5505 return bs->open_flags;
5508 int bdrv_has_zero_init_1(BlockDriverState *bs)
5513 int bdrv_has_zero_init(BlockDriverState *bs)
5515 BlockDriverState *filtered;
5521 /* If BS is a copy on write image, it is initialized to
5522 the contents of the base image, which may not be zeroes. */
5523 if (bdrv_cow_child(bs)) {
5526 if (bs->drv->bdrv_has_zero_init) {
5527 return bs->drv->bdrv_has_zero_init(bs);
5530 filtered = bdrv_filter_bs(bs);
5532 return bdrv_has_zero_init(filtered);
5539 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
5541 if (!(bs->open_flags & BDRV_O_UNMAP)) {
5545 return bs->supported_zero_flags & BDRV_REQ_MAY_UNMAP;
5548 void bdrv_get_backing_filename(BlockDriverState *bs,
5549 char *filename, int filename_size)
5551 pstrcpy(filename, filename_size, bs->backing_file);
5554 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
5556 BlockDriver *drv = bs->drv;
5557 /* if bs->drv == NULL, bs is closed, so there's nothing to do here */
5561 if (!drv->bdrv_get_info) {
5562 BlockDriverState *filtered = bdrv_filter_bs(bs);
5564 return bdrv_get_info(filtered, bdi);
5568 memset(bdi, 0, sizeof(*bdi));
5569 return drv->bdrv_get_info(bs, bdi);
5572 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
5575 BlockDriver *drv = bs->drv;
5576 if (drv && drv->bdrv_get_specific_info) {
5577 return drv->bdrv_get_specific_info(bs, errp);
5582 BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs)
5584 BlockDriver *drv = bs->drv;
5585 if (!drv || !drv->bdrv_get_specific_stats) {
5588 return drv->bdrv_get_specific_stats(bs);
5591 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event)
5593 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
5597 bs->drv->bdrv_debug_event(bs, event);
5600 static BlockDriverState *bdrv_find_debug_node(BlockDriverState *bs)
5602 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) {
5603 bs = bdrv_primary_bs(bs);
5606 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) {
5607 assert(bs->drv->bdrv_debug_remove_breakpoint);
5614 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
5617 bs = bdrv_find_debug_node(bs);
5619 return bs->drv->bdrv_debug_breakpoint(bs, event, tag);
5625 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag)
5627 bs = bdrv_find_debug_node(bs);
5629 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag);
5635 int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
5637 while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) {
5638 bs = bdrv_primary_bs(bs);
5641 if (bs && bs->drv && bs->drv->bdrv_debug_resume) {
5642 return bs->drv->bdrv_debug_resume(bs, tag);
5648 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag)
5650 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) {
5651 bs = bdrv_primary_bs(bs);
5654 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) {
5655 return bs->drv->bdrv_debug_is_suspended(bs, tag);
5661 /* backing_file can either be relative, or absolute, or a protocol. If it is
5662 * relative, it must be relative to the chain. So, passing in bs->filename
5663 * from a BDS as backing_file should not be done, as that may be relative to
5664 * the CWD rather than the chain. */
5665 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
5666 const char *backing_file)
5668 char *filename_full = NULL;
5669 char *backing_file_full = NULL;
5670 char *filename_tmp = NULL;
5671 int is_protocol = 0;
5672 bool filenames_refreshed = false;
5673 BlockDriverState *curr_bs = NULL;
5674 BlockDriverState *retval = NULL;
5675 BlockDriverState *bs_below;
5677 if (!bs || !bs->drv || !backing_file) {
5681 filename_full = g_malloc(PATH_MAX);
5682 backing_file_full = g_malloc(PATH_MAX);
5684 is_protocol = path_has_protocol(backing_file);
5687 * Being largely a legacy function, skip any filters here
5688 * (because filters do not have normal filenames, so they cannot
5689 * match anyway; and allowing json:{} filenames is a bit out of
5692 for (curr_bs = bdrv_skip_filters(bs);
5693 bdrv_cow_child(curr_bs) != NULL;
5696 bs_below = bdrv_backing_chain_next(curr_bs);
5698 if (bdrv_backing_overridden(curr_bs)) {
5700 * If the backing file was overridden, we can only compare
5701 * directly against the backing node's filename.
5704 if (!filenames_refreshed) {
5706 * This will automatically refresh all of the
5707 * filenames in the rest of the backing chain, so we
5708 * only need to do this once.
5710 bdrv_refresh_filename(bs_below);
5711 filenames_refreshed = true;
5714 if (strcmp(backing_file, bs_below->filename) == 0) {
5718 } else if (is_protocol || path_has_protocol(curr_bs->backing_file)) {
5720 * If either of the filename paths is actually a protocol, then
5721 * compare unmodified paths; otherwise make paths relative.
5723 char *backing_file_full_ret;
5725 if (strcmp(backing_file, curr_bs->backing_file) == 0) {
5729 /* Also check against the full backing filename for the image */
5730 backing_file_full_ret = bdrv_get_full_backing_filename(curr_bs,
5732 if (backing_file_full_ret) {
5733 bool equal = strcmp(backing_file, backing_file_full_ret) == 0;
5734 g_free(backing_file_full_ret);
5741 /* If not an absolute filename path, make it relative to the current
5742 * image's filename path */
5743 filename_tmp = bdrv_make_absolute_filename(curr_bs, backing_file,
5745 /* We are going to compare canonicalized absolute pathnames */
5746 if (!filename_tmp || !realpath(filename_tmp, filename_full)) {
5747 g_free(filename_tmp);
5750 g_free(filename_tmp);
5752 /* We need to make sure the backing filename we are comparing against
5753 * is relative to the current image filename (or absolute) */
5754 filename_tmp = bdrv_get_full_backing_filename(curr_bs, NULL);
5755 if (!filename_tmp || !realpath(filename_tmp, backing_file_full)) {
5756 g_free(filename_tmp);
5759 g_free(filename_tmp);
5761 if (strcmp(backing_file_full, filename_full) == 0) {
5768 g_free(filename_full);
5769 g_free(backing_file_full);
5773 void bdrv_init(void)
5775 module_call_init(MODULE_INIT_BLOCK);
5778 void bdrv_init_with_whitelist(void)
5780 use_bdrv_whitelist = 1;
5784 static void coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs,
5787 BdrvChild *child, *parent;
5788 uint64_t perm, shared_perm;
5789 Error *local_err = NULL;
5791 BdrvDirtyBitmap *bm;
5797 QLIST_FOREACH(child, &bs->children, next) {
5798 bdrv_co_invalidate_cache(child->bs, &local_err);
5800 error_propagate(errp, local_err);
5806 * Update permissions, they may differ for inactive nodes.
5808 * Note that the required permissions of inactive images are always a
5809 * subset of the permissions required after activating the image. This
5810 * allows us to just get the permissions upfront without restricting
5811 * drv->bdrv_invalidate_cache().
5813 * It also means that in error cases, we don't have to try and revert to
5814 * the old permissions (which is an operation that could fail, too). We can
5815 * just keep the extended permissions for the next time that an activation
5816 * of the image is tried.
5818 if (bs->open_flags & BDRV_O_INACTIVE) {
5819 bs->open_flags &= ~BDRV_O_INACTIVE;
5820 bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
5821 ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, NULL, errp);
5823 bs->open_flags |= BDRV_O_INACTIVE;
5826 bdrv_set_perm(bs, perm, shared_perm);
5828 if (bs->drv->bdrv_co_invalidate_cache) {
5829 bs->drv->bdrv_co_invalidate_cache(bs, &local_err);
5831 bs->open_flags |= BDRV_O_INACTIVE;
5832 error_propagate(errp, local_err);
5837 FOR_EACH_DIRTY_BITMAP(bs, bm) {
5838 bdrv_dirty_bitmap_skip_store(bm, false);
5841 ret = refresh_total_sectors(bs, bs->total_sectors);
5843 bs->open_flags |= BDRV_O_INACTIVE;
5844 error_setg_errno(errp, -ret, "Could not refresh total sector count");
5849 QLIST_FOREACH(parent, &bs->parents, next_parent) {
5850 if (parent->klass->activate) {
5851 parent->klass->activate(parent, &local_err);
5853 bs->open_flags |= BDRV_O_INACTIVE;
5854 error_propagate(errp, local_err);
5861 typedef struct InvalidateCacheCo {
5862 BlockDriverState *bs;
5865 } InvalidateCacheCo;
5867 static void coroutine_fn bdrv_invalidate_cache_co_entry(void *opaque)
5869 InvalidateCacheCo *ico = opaque;
5870 bdrv_co_invalidate_cache(ico->bs, ico->errp);
5875 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
5878 InvalidateCacheCo ico = {
5884 if (qemu_in_coroutine()) {
5885 /* Fast-path if already in coroutine context */
5886 bdrv_invalidate_cache_co_entry(&ico);
5888 co = qemu_coroutine_create(bdrv_invalidate_cache_co_entry, &ico);
5889 bdrv_coroutine_enter(bs, co);
5890 BDRV_POLL_WHILE(bs, !ico.done);
5894 void bdrv_invalidate_cache_all(Error **errp)
5896 BlockDriverState *bs;
5897 Error *local_err = NULL;
5898 BdrvNextIterator it;
5900 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
5901 AioContext *aio_context = bdrv_get_aio_context(bs);
5903 aio_context_acquire(aio_context);
5904 bdrv_invalidate_cache(bs, &local_err);
5905 aio_context_release(aio_context);
5907 error_propagate(errp, local_err);
5908 bdrv_next_cleanup(&it);
5914 static bool bdrv_has_bds_parent(BlockDriverState *bs, bool only_active)
5918 QLIST_FOREACH(parent, &bs->parents, next_parent) {
5919 if (parent->klass->parent_is_bds) {
5920 BlockDriverState *parent_bs = parent->opaque;
5921 if (!only_active || !(parent_bs->open_flags & BDRV_O_INACTIVE)) {
5930 static int bdrv_inactivate_recurse(BlockDriverState *bs)
5932 BdrvChild *child, *parent;
5933 bool tighten_restrictions;
5934 uint64_t perm, shared_perm;
5941 /* Make sure that we don't inactivate a child before its parent.
5942 * It will be covered by recursion from the yet active parent. */
5943 if (bdrv_has_bds_parent(bs, true)) {
5947 assert(!(bs->open_flags & BDRV_O_INACTIVE));
5949 /* Inactivate this node */
5950 if (bs->drv->bdrv_inactivate) {
5951 ret = bs->drv->bdrv_inactivate(bs);
5957 QLIST_FOREACH(parent, &bs->parents, next_parent) {
5958 if (parent->klass->inactivate) {
5959 ret = parent->klass->inactivate(parent);
5966 bs->open_flags |= BDRV_O_INACTIVE;
5968 /* Update permissions, they may differ for inactive nodes */
5969 bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
5970 ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL,
5971 &tighten_restrictions, NULL);
5972 assert(tighten_restrictions == false);
5974 /* We only tried to loosen restrictions, so errors are not fatal */
5975 bdrv_abort_perm_update(bs);
5977 bdrv_set_perm(bs, perm, shared_perm);
5981 /* Recursively inactivate children */
5982 QLIST_FOREACH(child, &bs->children, next) {
5983 ret = bdrv_inactivate_recurse(child->bs);
5992 int bdrv_inactivate_all(void)
5994 BlockDriverState *bs = NULL;
5995 BdrvNextIterator it;
5997 GSList *aio_ctxs = NULL, *ctx;
5999 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
6000 AioContext *aio_context = bdrv_get_aio_context(bs);
6002 if (!g_slist_find(aio_ctxs, aio_context)) {
6003 aio_ctxs = g_slist_prepend(aio_ctxs, aio_context);
6004 aio_context_acquire(aio_context);
6008 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
6009 /* Nodes with BDS parents are covered by recursion from the last
6010 * parent that gets inactivated. Don't inactivate them a second
6011 * time if that has already happened. */
6012 if (bdrv_has_bds_parent(bs, false)) {
6015 ret = bdrv_inactivate_recurse(bs);
6017 bdrv_next_cleanup(&it);
6023 for (ctx = aio_ctxs; ctx != NULL; ctx = ctx->next) {
6024 AioContext *aio_context = ctx->data;
6025 aio_context_release(aio_context);
6027 g_slist_free(aio_ctxs);
6032 /**************************************************************/
6033 /* removable device support */
6036 * Return TRUE if the media is present
6038 bool bdrv_is_inserted(BlockDriverState *bs)
6040 BlockDriver *drv = bs->drv;
6046 if (drv->bdrv_is_inserted) {
6047 return drv->bdrv_is_inserted(bs);
6049 QLIST_FOREACH(child, &bs->children, next) {
6050 if (!bdrv_is_inserted(child->bs)) {
6058 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
6060 void bdrv_eject(BlockDriverState *bs, bool eject_flag)
6062 BlockDriver *drv = bs->drv;
6064 if (drv && drv->bdrv_eject) {
6065 drv->bdrv_eject(bs, eject_flag);
6070 * Lock or unlock the media (if it is locked, the user won't be able
6071 * to eject it manually).
6073 void bdrv_lock_medium(BlockDriverState *bs, bool locked)
6075 BlockDriver *drv = bs->drv;
6077 trace_bdrv_lock_medium(bs, locked);
6079 if (drv && drv->bdrv_lock_medium) {
6080 drv->bdrv_lock_medium(bs, locked);
6084 /* Get a reference to bs */
6085 void bdrv_ref(BlockDriverState *bs)
6090 /* Release a previously grabbed reference to bs.
6091 * If after releasing, reference count is zero, the BlockDriverState is
6093 void bdrv_unref(BlockDriverState *bs)
6098 assert(bs->refcnt > 0);
6099 if (--bs->refcnt == 0) {
6104 struct BdrvOpBlocker {
6106 QLIST_ENTRY(BdrvOpBlocker) list;
6109 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp)
6111 BdrvOpBlocker *blocker;
6112 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
6113 if (!QLIST_EMPTY(&bs->op_blockers[op])) {
6114 blocker = QLIST_FIRST(&bs->op_blockers[op]);
6115 error_propagate_prepend(errp, error_copy(blocker->reason),
6116 "Node '%s' is busy: ",
6117 bdrv_get_device_or_node_name(bs));
6123 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason)
6125 BdrvOpBlocker *blocker;
6126 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
6128 blocker = g_new0(BdrvOpBlocker, 1);
6129 blocker->reason = reason;
6130 QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list);
6133 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason)
6135 BdrvOpBlocker *blocker, *next;
6136 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
6137 QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) {
6138 if (blocker->reason == reason) {
6139 QLIST_REMOVE(blocker, list);
6145 void bdrv_op_block_all(BlockDriverState *bs, Error *reason)
6148 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
6149 bdrv_op_block(bs, i, reason);
6153 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason)
6156 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
6157 bdrv_op_unblock(bs, i, reason);
6161 bool bdrv_op_blocker_is_empty(BlockDriverState *bs)
6165 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
6166 if (!QLIST_EMPTY(&bs->op_blockers[i])) {
6173 void bdrv_img_create(const char *filename, const char *fmt,
6174 const char *base_filename, const char *base_fmt,
6175 char *options, uint64_t img_size, int flags, bool quiet,
6178 QemuOptsList *create_opts = NULL;
6179 QemuOpts *opts = NULL;
6180 const char *backing_fmt, *backing_file;
6182 BlockDriver *drv, *proto_drv;
6183 Error *local_err = NULL;
6186 /* Find driver and parse its options */
6187 drv = bdrv_find_format(fmt);
6189 error_setg(errp, "Unknown file format '%s'", fmt);
6193 proto_drv = bdrv_find_protocol(filename, true, errp);
6198 if (!drv->create_opts) {
6199 error_setg(errp, "Format driver '%s' does not support image creation",
6204 if (!proto_drv->create_opts) {
6205 error_setg(errp, "Protocol driver '%s' does not support image creation",
6206 proto_drv->format_name);
6210 /* Create parameter list */
6211 create_opts = qemu_opts_append(create_opts, drv->create_opts);
6212 create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
6214 opts = qemu_opts_create(create_opts, NULL, 0, &error_abort);
6216 /* Parse -o options */
6218 if (!qemu_opts_do_parse(opts, options, NULL, errp)) {
6223 if (!qemu_opt_get(opts, BLOCK_OPT_SIZE)) {
6224 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, img_size, &error_abort);
6225 } else if (img_size != UINT64_C(-1)) {
6226 error_setg(errp, "The image size must be specified only once");
6230 if (base_filename) {
6231 if (!qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename,
6233 error_setg(errp, "Backing file not supported for file format '%s'",
6240 if (!qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt, NULL)) {
6241 error_setg(errp, "Backing file format not supported for file "
6242 "format '%s'", fmt);
6247 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
6249 if (!strcmp(filename, backing_file)) {
6250 error_setg(errp, "Error: Trying to create an image with the "
6251 "same filename as the backing file");
6254 if (backing_file[0] == '\0') {
6255 error_setg(errp, "Expected backing file name, got empty string");
6260 backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
6262 /* The size for the image must always be specified, unless we have a backing
6263 * file and we have not been forbidden from opening it. */
6264 size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, img_size);
6265 if (backing_file && !(flags & BDRV_O_NO_BACKING)) {
6266 BlockDriverState *bs;
6269 QDict *backing_options = NULL;
6272 bdrv_get_full_backing_filename_from_filename(filename, backing_file,
6277 assert(full_backing);
6279 /* backing files always opened read-only */
6281 back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
6283 backing_options = qdict_new();
6285 qdict_put_str(backing_options, "driver", backing_fmt);
6287 qdict_put_bool(backing_options, BDRV_OPT_FORCE_SHARE, true);
6289 bs = bdrv_open(full_backing, NULL, backing_options, back_flags,
6291 g_free(full_backing);
6293 error_append_hint(&local_err, "Could not open backing image.\n");
6297 warn_report("Deprecated use of backing file without explicit "
6298 "backing format (detected format of %s)",
6299 bs->drv->format_name);
6300 if (bs->drv != &bdrv_raw) {
6302 * A probe of raw deserves the most attention:
6303 * leaving the backing format out of the image
6304 * will ensure bs->probed is set (ensuring we
6305 * don't accidentally commit into the backing
6306 * file), and allow more spots to warn the users
6307 * to fix their toolchain when opening this image
6308 * later. For other images, we can safely record
6309 * the format that we probed.
6311 backing_fmt = bs->drv->format_name;
6312 qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, backing_fmt,
6317 /* Opened BS, have no size */
6318 size = bdrv_getlength(bs);
6320 error_setg_errno(errp, -size, "Could not get size of '%s'",
6325 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort);
6329 /* (backing_file && !(flags & BDRV_O_NO_BACKING)) */
6330 } else if (backing_file && !backing_fmt) {
6331 warn_report("Deprecated use of unopened backing file without "
6332 "explicit backing format, use of this image requires "
6333 "potentially unsafe format probing");
6337 error_setg(errp, "Image creation needs a size parameter");
6342 printf("Formatting '%s', fmt=%s ", filename, fmt);
6343 qemu_opts_print(opts, " ");
6348 ret = bdrv_create(drv, filename, opts, &local_err);
6350 if (ret == -EFBIG) {
6351 /* This is generally a better message than whatever the driver would
6352 * deliver (especially because of the cluster_size_hint), since that
6353 * is most probably not much different from "image too large". */
6354 const char *cluster_size_hint = "";
6355 if (qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 0)) {
6356 cluster_size_hint = " (try using a larger cluster size)";
6358 error_setg(errp, "The image size is too large for file format '%s'"
6359 "%s", fmt, cluster_size_hint);
6360 error_free(local_err);
6365 qemu_opts_del(opts);
6366 qemu_opts_free(create_opts);
6367 error_propagate(errp, local_err);
6370 AioContext *bdrv_get_aio_context(BlockDriverState *bs)
6372 return bs ? bs->aio_context : qemu_get_aio_context();
6375 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co)
6377 aio_co_enter(bdrv_get_aio_context(bs), co);
6380 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban)
6382 QLIST_REMOVE(ban, list);
6386 static void bdrv_detach_aio_context(BlockDriverState *bs)
6388 BdrvAioNotifier *baf, *baf_tmp;
6390 assert(!bs->walking_aio_notifiers);
6391 bs->walking_aio_notifiers = true;
6392 QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) {
6394 bdrv_do_remove_aio_context_notifier(baf);
6396 baf->detach_aio_context(baf->opaque);
6399 /* Never mind iterating again to check for ->deleted. bdrv_close() will
6400 * remove remaining aio notifiers if we aren't called again.
6402 bs->walking_aio_notifiers = false;
6404 if (bs->drv && bs->drv->bdrv_detach_aio_context) {
6405 bs->drv->bdrv_detach_aio_context(bs);
6408 if (bs->quiesce_counter) {
6409 aio_enable_external(bs->aio_context);
6411 bs->aio_context = NULL;
6414 static void bdrv_attach_aio_context(BlockDriverState *bs,
6415 AioContext *new_context)
6417 BdrvAioNotifier *ban, *ban_tmp;
6419 if (bs->quiesce_counter) {
6420 aio_disable_external(new_context);
6423 bs->aio_context = new_context;
6425 if (bs->drv && bs->drv->bdrv_attach_aio_context) {
6426 bs->drv->bdrv_attach_aio_context(bs, new_context);
6429 assert(!bs->walking_aio_notifiers);
6430 bs->walking_aio_notifiers = true;
6431 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_tmp) {
6433 bdrv_do_remove_aio_context_notifier(ban);
6435 ban->attached_aio_context(new_context, ban->opaque);
6438 bs->walking_aio_notifiers = false;
6442 * Changes the AioContext used for fd handlers, timers, and BHs by this
6443 * BlockDriverState and all its children and parents.
6445 * Must be called from the main AioContext.
6447 * The caller must own the AioContext lock for the old AioContext of bs, but it
6448 * must not own the AioContext lock for new_context (unless new_context is the
6449 * same as the current context of bs).
6451 * @ignore will accumulate all visited BdrvChild object. The caller is
6452 * responsible for freeing the list afterwards.
6454 void bdrv_set_aio_context_ignore(BlockDriverState *bs,
6455 AioContext *new_context, GSList **ignore)
6457 AioContext *old_context = bdrv_get_aio_context(bs);
6460 g_assert(qemu_get_current_aio_context() == qemu_get_aio_context());
6462 if (old_context == new_context) {
6466 bdrv_drained_begin(bs);
6468 QLIST_FOREACH(child, &bs->children, next) {
6469 if (g_slist_find(*ignore, child)) {
6472 *ignore = g_slist_prepend(*ignore, child);
6473 bdrv_set_aio_context_ignore(child->bs, new_context, ignore);
6475 QLIST_FOREACH(child, &bs->parents, next_parent) {
6476 if (g_slist_find(*ignore, child)) {
6479 assert(child->klass->set_aio_ctx);
6480 *ignore = g_slist_prepend(*ignore, child);
6481 child->klass->set_aio_ctx(child, new_context, ignore);
6484 bdrv_detach_aio_context(bs);
6486 /* Acquire the new context, if necessary */
6487 if (qemu_get_aio_context() != new_context) {
6488 aio_context_acquire(new_context);
6491 bdrv_attach_aio_context(bs, new_context);
6494 * If this function was recursively called from
6495 * bdrv_set_aio_context_ignore(), there may be nodes in the
6496 * subtree that have not yet been moved to the new AioContext.
6497 * Release the old one so bdrv_drained_end() can poll them.
6499 if (qemu_get_aio_context() != old_context) {
6500 aio_context_release(old_context);
6503 bdrv_drained_end(bs);
6505 if (qemu_get_aio_context() != old_context) {
6506 aio_context_acquire(old_context);
6508 if (qemu_get_aio_context() != new_context) {
6509 aio_context_release(new_context);
6513 static bool bdrv_parent_can_set_aio_context(BdrvChild *c, AioContext *ctx,
6514 GSList **ignore, Error **errp)
6516 if (g_slist_find(*ignore, c)) {
6519 *ignore = g_slist_prepend(*ignore, c);
6522 * A BdrvChildClass that doesn't handle AioContext changes cannot
6523 * tolerate any AioContext changes
6525 if (!c->klass->can_set_aio_ctx) {
6526 char *user = bdrv_child_user_desc(c);
6527 error_setg(errp, "Changing iothreads is not supported by %s", user);
6531 if (!c->klass->can_set_aio_ctx(c, ctx, ignore, errp)) {
6532 assert(!errp || *errp);
6538 bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx,
6539 GSList **ignore, Error **errp)
6541 if (g_slist_find(*ignore, c)) {
6544 *ignore = g_slist_prepend(*ignore, c);
6545 return bdrv_can_set_aio_context(c->bs, ctx, ignore, errp);
6548 /* @ignore will accumulate all visited BdrvChild object. The caller is
6549 * responsible for freeing the list afterwards. */
6550 bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx,
6551 GSList **ignore, Error **errp)
6555 if (bdrv_get_aio_context(bs) == ctx) {
6559 QLIST_FOREACH(c, &bs->parents, next_parent) {
6560 if (!bdrv_parent_can_set_aio_context(c, ctx, ignore, errp)) {
6564 QLIST_FOREACH(c, &bs->children, next) {
6565 if (!bdrv_child_can_set_aio_context(c, ctx, ignore, errp)) {
6573 int bdrv_child_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
6574 BdrvChild *ignore_child, Error **errp)
6579 ignore = ignore_child ? g_slist_prepend(NULL, ignore_child) : NULL;
6580 ret = bdrv_can_set_aio_context(bs, ctx, &ignore, errp);
6581 g_slist_free(ignore);
6587 ignore = ignore_child ? g_slist_prepend(NULL, ignore_child) : NULL;
6588 bdrv_set_aio_context_ignore(bs, ctx, &ignore);
6589 g_slist_free(ignore);
6594 int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
6597 return bdrv_child_try_set_aio_context(bs, ctx, NULL, errp);
6600 void bdrv_add_aio_context_notifier(BlockDriverState *bs,
6601 void (*attached_aio_context)(AioContext *new_context, void *opaque),
6602 void (*detach_aio_context)(void *opaque), void *opaque)
6604 BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1);
6605 *ban = (BdrvAioNotifier){
6606 .attached_aio_context = attached_aio_context,
6607 .detach_aio_context = detach_aio_context,
6611 QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list);
6614 void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
6615 void (*attached_aio_context)(AioContext *,
6617 void (*detach_aio_context)(void *),
6620 BdrvAioNotifier *ban, *ban_next;
6622 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
6623 if (ban->attached_aio_context == attached_aio_context &&
6624 ban->detach_aio_context == detach_aio_context &&
6625 ban->opaque == opaque &&
6626 ban->deleted == false)
6628 if (bs->walking_aio_notifiers) {
6629 ban->deleted = true;
6631 bdrv_do_remove_aio_context_notifier(ban);
6640 int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts,
6641 BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
6646 error_setg(errp, "Node is ejected");
6649 if (!bs->drv->bdrv_amend_options) {
6650 error_setg(errp, "Block driver '%s' does not support option amendment",
6651 bs->drv->format_name);
6654 return bs->drv->bdrv_amend_options(bs, opts, status_cb,
6655 cb_opaque, force, errp);
6659 * This function checks whether the given @to_replace is allowed to be
6660 * replaced by a node that always shows the same data as @bs. This is
6661 * used for example to verify whether the mirror job can replace
6662 * @to_replace by the target mirrored from @bs.
6663 * To be replaceable, @bs and @to_replace may either be guaranteed to
6664 * always show the same data (because they are only connected through
6665 * filters), or some driver may allow replacing one of its children
6666 * because it can guarantee that this child's data is not visible at
6667 * all (for example, for dissenting quorum children that have no other
6670 bool bdrv_recurse_can_replace(BlockDriverState *bs,
6671 BlockDriverState *to_replace)
6673 BlockDriverState *filtered;
6675 if (!bs || !bs->drv) {
6679 if (bs == to_replace) {
6683 /* See what the driver can do */
6684 if (bs->drv->bdrv_recurse_can_replace) {
6685 return bs->drv->bdrv_recurse_can_replace(bs, to_replace);
6688 /* For filters without an own implementation, we can recurse on our own */
6689 filtered = bdrv_filter_bs(bs);
6691 return bdrv_recurse_can_replace(filtered, to_replace);
6699 * Check whether the given @node_name can be replaced by a node that
6700 * has the same data as @parent_bs. If so, return @node_name's BDS;
6703 * @node_name must be a (recursive) *child of @parent_bs (or this
6704 * function will return NULL).
6706 * The result (whether the node can be replaced or not) is only valid
6707 * for as long as no graph or permission changes occur.
6709 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
6710 const char *node_name, Error **errp)
6712 BlockDriverState *to_replace_bs = bdrv_find_node(node_name);
6713 AioContext *aio_context;
6715 if (!to_replace_bs) {
6716 error_setg(errp, "Node name '%s' not found", node_name);
6720 aio_context = bdrv_get_aio_context(to_replace_bs);
6721 aio_context_acquire(aio_context);
6723 if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) {
6724 to_replace_bs = NULL;
6728 /* We don't want arbitrary node of the BDS chain to be replaced only the top
6729 * most non filter in order to prevent data corruption.
6730 * Another benefit is that this tests exclude backing files which are
6731 * blocked by the backing blockers.
6733 if (!bdrv_recurse_can_replace(parent_bs, to_replace_bs)) {
6734 error_setg(errp, "Cannot replace '%s' by a node mirrored from '%s', "
6735 "because it cannot be guaranteed that doing so would not "
6736 "lead to an abrupt change of visible data",
6737 node_name, parent_bs->node_name);
6738 to_replace_bs = NULL;
6743 aio_context_release(aio_context);
6744 return to_replace_bs;
6748 * Iterates through the list of runtime option keys that are said to
6749 * be "strong" for a BDS. An option is called "strong" if it changes
6750 * a BDS's data. For example, the null block driver's "size" and
6751 * "read-zeroes" options are strong, but its "latency-ns" option is
6754 * If a key returned by this function ends with a dot, all options
6755 * starting with that prefix are strong.
6757 static const char *const *strong_options(BlockDriverState *bs,
6758 const char *const *curopt)
6760 static const char *const global_options[] = {
6761 "driver", "filename", NULL
6765 return &global_options[0];
6769 if (curopt == &global_options[ARRAY_SIZE(global_options) - 1] && bs->drv) {
6770 curopt = bs->drv->strong_runtime_opts;
6773 return (curopt && *curopt) ? curopt : NULL;
6777 * Copies all strong runtime options from bs->options to the given
6778 * QDict. The set of strong option keys is determined by invoking
6781 * Returns true iff any strong option was present in bs->options (and
6782 * thus copied to the target QDict) with the exception of "filename"
6783 * and "driver". The caller is expected to use this value to decide
6784 * whether the existence of strong options prevents the generation of
6787 static bool append_strong_runtime_options(QDict *d, BlockDriverState *bs)
6789 bool found_any = false;
6790 const char *const *option_name = NULL;
6796 while ((option_name = strong_options(bs, option_name))) {
6797 bool option_given = false;
6799 assert(strlen(*option_name) > 0);
6800 if ((*option_name)[strlen(*option_name) - 1] != '.') {
6801 QObject *entry = qdict_get(bs->options, *option_name);
6806 qdict_put_obj(d, *option_name, qobject_ref(entry));
6807 option_given = true;
6809 const QDictEntry *entry;
6810 for (entry = qdict_first(bs->options); entry;
6811 entry = qdict_next(bs->options, entry))
6813 if (strstart(qdict_entry_key(entry), *option_name, NULL)) {
6814 qdict_put_obj(d, qdict_entry_key(entry),
6815 qobject_ref(qdict_entry_value(entry)));
6816 option_given = true;
6821 /* While "driver" and "filename" need to be included in a JSON filename,
6822 * their existence does not prohibit generation of a plain filename. */
6823 if (!found_any && option_given &&
6824 strcmp(*option_name, "driver") && strcmp(*option_name, "filename"))
6830 if (!qdict_haskey(d, "driver")) {
6831 /* Drivers created with bdrv_new_open_driver() may not have a
6832 * @driver option. Add it here. */
6833 qdict_put_str(d, "driver", bs->drv->format_name);
6839 /* Note: This function may return false positives; it may return true
6840 * even if opening the backing file specified by bs's image header
6841 * would result in exactly bs->backing. */
6842 bool bdrv_backing_overridden(BlockDriverState *bs)
6845 return strcmp(bs->auto_backing_file,
6846 bs->backing->bs->filename);
6848 /* No backing BDS, so if the image header reports any backing
6849 * file, it must have been suppressed */
6850 return bs->auto_backing_file[0] != '\0';
6854 /* Updates the following BDS fields:
6855 * - exact_filename: A filename which may be used for opening a block device
6856 * which (mostly) equals the given BDS (even without any
6857 * other options; so reading and writing must return the same
6858 * results, but caching etc. may be different)
6859 * - full_open_options: Options which, when given when opening a block device
6860 * (without a filename), result in a BDS (mostly)
6861 * equalling the given one
6862 * - filename: If exact_filename is set, it is copied here. Otherwise,
6863 * full_open_options is converted to a JSON object, prefixed with
6864 * "json:" (for use through the JSON pseudo protocol) and put here.
6866 void bdrv_refresh_filename(BlockDriverState *bs)
6868 BlockDriver *drv = bs->drv;
6870 BlockDriverState *primary_child_bs;
6872 bool backing_overridden;
6873 bool generate_json_filename; /* Whether our default implementation should
6874 fill exact_filename (false) or not (true) */
6880 /* This BDS's file name may depend on any of its children's file names, so
6881 * refresh those first */
6882 QLIST_FOREACH(child, &bs->children, next) {
6883 bdrv_refresh_filename(child->bs);
6887 /* For implicit nodes, just copy everything from the single child */
6888 child = QLIST_FIRST(&bs->children);
6889 assert(QLIST_NEXT(child, next) == NULL);
6891 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
6892 child->bs->exact_filename);
6893 pstrcpy(bs->filename, sizeof(bs->filename), child->bs->filename);
6895 qobject_unref(bs->full_open_options);
6896 bs->full_open_options = qobject_ref(child->bs->full_open_options);
6901 backing_overridden = bdrv_backing_overridden(bs);
6903 if (bs->open_flags & BDRV_O_NO_IO) {
6904 /* Without I/O, the backing file does not change anything.
6905 * Therefore, in such a case (primarily qemu-img), we can
6906 * pretend the backing file has not been overridden even if
6907 * it technically has been. */
6908 backing_overridden = false;
6911 /* Gather the options QDict */
6913 generate_json_filename = append_strong_runtime_options(opts, bs);
6914 generate_json_filename |= backing_overridden;
6916 if (drv->bdrv_gather_child_options) {
6917 /* Some block drivers may not want to present all of their children's
6918 * options, or name them differently from BdrvChild.name */
6919 drv->bdrv_gather_child_options(bs, opts, backing_overridden);
6921 QLIST_FOREACH(child, &bs->children, next) {
6922 if (child == bs->backing && !backing_overridden) {
6923 /* We can skip the backing BDS if it has not been overridden */
6927 qdict_put(opts, child->name,
6928 qobject_ref(child->bs->full_open_options));
6931 if (backing_overridden && !bs->backing) {
6932 /* Force no backing file */
6933 qdict_put_null(opts, "backing");
6937 qobject_unref(bs->full_open_options);
6938 bs->full_open_options = opts;
6940 primary_child_bs = bdrv_primary_bs(bs);
6942 if (drv->bdrv_refresh_filename) {
6943 /* Obsolete information is of no use here, so drop the old file name
6944 * information before refreshing it */
6945 bs->exact_filename[0] = '\0';
6947 drv->bdrv_refresh_filename(bs);
6948 } else if (primary_child_bs) {
6950 * Try to reconstruct valid information from the underlying
6951 * file -- this only works for format nodes (filter nodes
6952 * cannot be probed and as such must be selected by the user
6953 * either through an options dict, or through a special
6954 * filename which the filter driver must construct in its
6955 * .bdrv_refresh_filename() implementation).
6958 bs->exact_filename[0] = '\0';
6961 * We can use the underlying file's filename if:
6962 * - it has a filename,
6963 * - the current BDS is not a filter,
6964 * - the file is a protocol BDS, and
6965 * - opening that file (as this BDS's format) will automatically create
6966 * the BDS tree we have right now, that is:
6967 * - the user did not significantly change this BDS's behavior with
6968 * some explicit (strong) options
6969 * - no non-file child of this BDS has been overridden by the user
6970 * Both of these conditions are represented by generate_json_filename.
6972 if (primary_child_bs->exact_filename[0] &&
6973 primary_child_bs->drv->bdrv_file_open &&
6974 !drv->is_filter && !generate_json_filename)
6976 strcpy(bs->exact_filename, primary_child_bs->exact_filename);
6980 if (bs->exact_filename[0]) {
6981 pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename);
6983 QString *json = qobject_to_json(QOBJECT(bs->full_open_options));
6984 if (snprintf(bs->filename, sizeof(bs->filename), "json:%s",
6985 qstring_get_str(json)) >= sizeof(bs->filename)) {
6986 /* Give user a hint if we truncated things. */
6987 strcpy(bs->filename + sizeof(bs->filename) - 4, "...");
6989 qobject_unref(json);
6993 char *bdrv_dirname(BlockDriverState *bs, Error **errp)
6995 BlockDriver *drv = bs->drv;
6996 BlockDriverState *child_bs;
6999 error_setg(errp, "Node '%s' is ejected", bs->node_name);
7003 if (drv->bdrv_dirname) {
7004 return drv->bdrv_dirname(bs, errp);
7007 child_bs = bdrv_primary_bs(bs);
7009 return bdrv_dirname(child_bs, errp);
7012 bdrv_refresh_filename(bs);
7013 if (bs->exact_filename[0] != '\0') {
7014 return path_combine(bs->exact_filename, "");
7017 error_setg(errp, "Cannot generate a base directory for %s nodes",
7023 * Hot add/remove a BDS's child. So the user can take a child offline when
7024 * it is broken and take a new child online
7026 void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs,
7030 if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) {
7031 error_setg(errp, "The node %s does not support adding a child",
7032 bdrv_get_device_or_node_name(parent_bs));
7036 if (!QLIST_EMPTY(&child_bs->parents)) {
7037 error_setg(errp, "The node %s already has a parent",
7038 child_bs->node_name);
7042 parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp);
7045 void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp)
7049 if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) {
7050 error_setg(errp, "The node %s does not support removing a child",
7051 bdrv_get_device_or_node_name(parent_bs));
7055 QLIST_FOREACH(tmp, &parent_bs->children, next) {
7062 error_setg(errp, "The node %s does not have a child named %s",
7063 bdrv_get_device_or_node_name(parent_bs),
7064 bdrv_get_device_or_node_name(child->bs));
7068 parent_bs->drv->bdrv_del_child(parent_bs, child, errp);
7071 int bdrv_make_empty(BdrvChild *c, Error **errp)
7073 BlockDriver *drv = c->bs->drv;
7076 assert(c->perm & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED));
7078 if (!drv->bdrv_make_empty) {
7079 error_setg(errp, "%s does not support emptying nodes",
7084 ret = drv->bdrv_make_empty(c->bs);
7086 error_setg_errno(errp, -ret, "Failed to empty %s",
7095 * Return the child that @bs acts as an overlay for, and from which data may be
7096 * copied in COW or COR operations. Usually this is the backing file.
7098 BdrvChild *bdrv_cow_child(BlockDriverState *bs)
7100 if (!bs || !bs->drv) {
7104 if (bs->drv->is_filter) {
7112 assert(bs->backing->role & BDRV_CHILD_COW);
7117 * If @bs acts as a filter for exactly one of its children, return
7120 BdrvChild *bdrv_filter_child(BlockDriverState *bs)
7124 if (!bs || !bs->drv) {
7128 if (!bs->drv->is_filter) {
7132 /* Only one of @backing or @file may be used */
7133 assert(!(bs->backing && bs->file));
7135 c = bs->backing ?: bs->file;
7140 assert(c->role & BDRV_CHILD_FILTERED);
7145 * Return either the result of bdrv_cow_child() or bdrv_filter_child(),
7146 * whichever is non-NULL.
7148 * Return NULL if both are NULL.
7150 BdrvChild *bdrv_filter_or_cow_child(BlockDriverState *bs)
7152 BdrvChild *cow_child = bdrv_cow_child(bs);
7153 BdrvChild *filter_child = bdrv_filter_child(bs);
7155 /* Filter nodes cannot have COW backing files */
7156 assert(!(cow_child && filter_child));
7158 return cow_child ?: filter_child;
7162 * Return the primary child of this node: For filters, that is the
7163 * filtered child. For other nodes, that is usually the child storing
7165 * (A generally more helpful description is that this is (usually) the
7166 * child that has the same filename as @bs.)
7168 * Drivers do not necessarily have a primary child; for example quorum
7171 BdrvChild *bdrv_primary_child(BlockDriverState *bs)
7173 BdrvChild *c, *found = NULL;
7175 QLIST_FOREACH(c, &bs->children, next) {
7176 if (c->role & BDRV_CHILD_PRIMARY) {
7185 static BlockDriverState *bdrv_do_skip_filters(BlockDriverState *bs,
7186 bool stop_on_explicit_filter)
7194 while (!(stop_on_explicit_filter && !bs->implicit)) {
7195 c = bdrv_filter_child(bs);
7198 * A filter that is embedded in a working block graph must
7199 * have a child. Assert this here so this function does
7200 * not return a filter node that is not expected by the
7203 assert(!bs->drv || !bs->drv->is_filter);
7209 * Note that this treats nodes with bs->drv == NULL as not being
7210 * filters (bs->drv == NULL should be replaced by something else
7212 * The advantage of this behavior is that this function will thus
7213 * always return a non-NULL value (given a non-NULL @bs).
7220 * Return the first BDS that has not been added implicitly or that
7221 * does not have a filtered child down the chain starting from @bs
7222 * (including @bs itself).
7224 BlockDriverState *bdrv_skip_implicit_filters(BlockDriverState *bs)
7226 return bdrv_do_skip_filters(bs, true);
7230 * Return the first BDS that does not have a filtered child down the
7231 * chain starting from @bs (including @bs itself).
7233 BlockDriverState *bdrv_skip_filters(BlockDriverState *bs)
7235 return bdrv_do_skip_filters(bs, false);
7239 * For a backing chain, return the first non-filter backing image of
7240 * the first non-filter image.
7242 BlockDriverState *bdrv_backing_chain_next(BlockDriverState *bs)
7244 return bdrv_skip_filters(bdrv_cow_bs(bdrv_skip_filters(bs)));