pxa2xx: Auto-assign name for i2c bus in i2c_init_bus.
[qemu/ar7.git] / block.c
blob7f3e7bcdc3403e6045a03a4861811d2a6c561e3b
1 /*
2 * QEMU System Emulator block driver
4 * Copyright (c) 2003 Fabrice Bellard
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
24 #include "qemu/osdep.h"
25 #include "trace.h"
26 #include "block/block_int.h"
27 #include "block/blockjob.h"
28 #include "block/nbd.h"
29 #include "qemu/error-report.h"
30 #include "module_block.h"
31 #include "qemu/module.h"
32 #include "qapi/qmp/qerror.h"
33 #include "qapi/qmp/qbool.h"
34 #include "qapi/qmp/qjson.h"
35 #include "sysemu/block-backend.h"
36 #include "sysemu/sysemu.h"
37 #include "qemu/notify.h"
38 #include "qemu/coroutine.h"
39 #include "block/qapi.h"
40 #include "qmp-commands.h"
41 #include "qemu/timer.h"
42 #include "qapi-event.h"
43 #include "qemu/cutils.h"
44 #include "qemu/id.h"
45 #include "qapi/util.h"
47 #ifdef CONFIG_BSD
48 #include <sys/ioctl.h>
49 #include <sys/queue.h>
50 #ifndef __DragonFly__
51 #include <sys/disk.h>
52 #endif
53 #endif
55 #ifdef _WIN32
56 #include <windows.h>
57 #endif
59 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
61 static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states =
62 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states);
64 static QTAILQ_HEAD(, BlockDriverState) all_bdrv_states =
65 QTAILQ_HEAD_INITIALIZER(all_bdrv_states);
67 static QLIST_HEAD(, BlockDriver) bdrv_drivers =
68 QLIST_HEAD_INITIALIZER(bdrv_drivers);
70 static BlockDriverState *bdrv_open_inherit(const char *filename,
71 const char *reference,
72 QDict *options, int flags,
73 BlockDriverState *parent,
74 const BdrvChildRole *child_role,
75 Error **errp);
77 /* If non-zero, use only whitelisted block drivers */
78 static int use_bdrv_whitelist;
80 #ifdef _WIN32
81 static int is_windows_drive_prefix(const char *filename)
83 return (((filename[0] >= 'a' && filename[0] <= 'z') ||
84 (filename[0] >= 'A' && filename[0] <= 'Z')) &&
85 filename[1] == ':');
88 int is_windows_drive(const char *filename)
90 if (is_windows_drive_prefix(filename) &&
91 filename[2] == '\0')
92 return 1;
93 if (strstart(filename, "\\\\.\\", NULL) ||
94 strstart(filename, "//./", NULL))
95 return 1;
96 return 0;
98 #endif
100 size_t bdrv_opt_mem_align(BlockDriverState *bs)
102 if (!bs || !bs->drv) {
103 /* page size or 4k (hdd sector size) should be on the safe side */
104 return MAX(4096, getpagesize());
107 return bs->bl.opt_mem_alignment;
110 size_t bdrv_min_mem_align(BlockDriverState *bs)
112 if (!bs || !bs->drv) {
113 /* page size or 4k (hdd sector size) should be on the safe side */
114 return MAX(4096, getpagesize());
117 return bs->bl.min_mem_alignment;
120 /* check if the path starts with "<protocol>:" */
121 int path_has_protocol(const char *path)
123 const char *p;
125 #ifdef _WIN32
126 if (is_windows_drive(path) ||
127 is_windows_drive_prefix(path)) {
128 return 0;
130 p = path + strcspn(path, ":/\\");
131 #else
132 p = path + strcspn(path, ":/");
133 #endif
135 return *p == ':';
138 int path_is_absolute(const char *path)
140 #ifdef _WIN32
141 /* specific case for names like: "\\.\d:" */
142 if (is_windows_drive(path) || is_windows_drive_prefix(path)) {
143 return 1;
145 return (*path == '/' || *path == '\\');
146 #else
147 return (*path == '/');
148 #endif
151 /* if filename is absolute, just copy it to dest. Otherwise, build a
152 path to it by considering it is relative to base_path. URL are
153 supported. */
154 void path_combine(char *dest, int dest_size,
155 const char *base_path,
156 const char *filename)
158 const char *p, *p1;
159 int len;
161 if (dest_size <= 0)
162 return;
163 if (path_is_absolute(filename)) {
164 pstrcpy(dest, dest_size, filename);
165 } else {
166 p = strchr(base_path, ':');
167 if (p)
168 p++;
169 else
170 p = base_path;
171 p1 = strrchr(base_path, '/');
172 #ifdef _WIN32
174 const char *p2;
175 p2 = strrchr(base_path, '\\');
176 if (!p1 || p2 > p1)
177 p1 = p2;
179 #endif
180 if (p1)
181 p1++;
182 else
183 p1 = base_path;
184 if (p1 > p)
185 p = p1;
186 len = p - base_path;
187 if (len > dest_size - 1)
188 len = dest_size - 1;
189 memcpy(dest, base_path, len);
190 dest[len] = '\0';
191 pstrcat(dest, dest_size, filename);
195 void bdrv_get_full_backing_filename_from_filename(const char *backed,
196 const char *backing,
197 char *dest, size_t sz,
198 Error **errp)
200 if (backing[0] == '\0' || path_has_protocol(backing) ||
201 path_is_absolute(backing))
203 pstrcpy(dest, sz, backing);
204 } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) {
205 error_setg(errp, "Cannot use relative backing file names for '%s'",
206 backed);
207 } else {
208 path_combine(dest, sz, backed, backing);
212 void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz,
213 Error **errp)
215 char *backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename;
217 bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file,
218 dest, sz, errp);
221 void bdrv_register(BlockDriver *bdrv)
223 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list);
226 BlockDriverState *bdrv_new(void)
228 BlockDriverState *bs;
229 int i;
231 bs = g_new0(BlockDriverState, 1);
232 QLIST_INIT(&bs->dirty_bitmaps);
233 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
234 QLIST_INIT(&bs->op_blockers[i]);
236 notifier_with_return_list_init(&bs->before_write_notifiers);
237 bs->refcnt = 1;
238 bs->aio_context = qemu_get_aio_context();
240 qemu_co_queue_init(&bs->flush_queue);
242 QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list);
244 return bs;
247 static BlockDriver *bdrv_do_find_format(const char *format_name)
249 BlockDriver *drv1;
251 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
252 if (!strcmp(drv1->format_name, format_name)) {
253 return drv1;
257 return NULL;
260 BlockDriver *bdrv_find_format(const char *format_name)
262 BlockDriver *drv1;
263 int i;
265 drv1 = bdrv_do_find_format(format_name);
266 if (drv1) {
267 return drv1;
270 /* The driver isn't registered, maybe we need to load a module */
271 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
272 if (!strcmp(block_driver_modules[i].format_name, format_name)) {
273 block_module_load_one(block_driver_modules[i].library_name);
274 break;
278 return bdrv_do_find_format(format_name);
281 static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
283 static const char *whitelist_rw[] = {
284 CONFIG_BDRV_RW_WHITELIST
286 static const char *whitelist_ro[] = {
287 CONFIG_BDRV_RO_WHITELIST
289 const char **p;
291 if (!whitelist_rw[0] && !whitelist_ro[0]) {
292 return 1; /* no whitelist, anything goes */
295 for (p = whitelist_rw; *p; p++) {
296 if (!strcmp(drv->format_name, *p)) {
297 return 1;
300 if (read_only) {
301 for (p = whitelist_ro; *p; p++) {
302 if (!strcmp(drv->format_name, *p)) {
303 return 1;
307 return 0;
310 bool bdrv_uses_whitelist(void)
312 return use_bdrv_whitelist;
315 typedef struct CreateCo {
316 BlockDriver *drv;
317 char *filename;
318 QemuOpts *opts;
319 int ret;
320 Error *err;
321 } CreateCo;
323 static void coroutine_fn bdrv_create_co_entry(void *opaque)
325 Error *local_err = NULL;
326 int ret;
328 CreateCo *cco = opaque;
329 assert(cco->drv);
331 ret = cco->drv->bdrv_create(cco->filename, cco->opts, &local_err);
332 error_propagate(&cco->err, local_err);
333 cco->ret = ret;
336 int bdrv_create(BlockDriver *drv, const char* filename,
337 QemuOpts *opts, Error **errp)
339 int ret;
341 Coroutine *co;
342 CreateCo cco = {
343 .drv = drv,
344 .filename = g_strdup(filename),
345 .opts = opts,
346 .ret = NOT_DONE,
347 .err = NULL,
350 if (!drv->bdrv_create) {
351 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name);
352 ret = -ENOTSUP;
353 goto out;
356 if (qemu_in_coroutine()) {
357 /* Fast-path if already in coroutine context */
358 bdrv_create_co_entry(&cco);
359 } else {
360 co = qemu_coroutine_create(bdrv_create_co_entry, &cco);
361 qemu_coroutine_enter(co);
362 while (cco.ret == NOT_DONE) {
363 aio_poll(qemu_get_aio_context(), true);
367 ret = cco.ret;
368 if (ret < 0) {
369 if (cco.err) {
370 error_propagate(errp, cco.err);
371 } else {
372 error_setg_errno(errp, -ret, "Could not create image");
376 out:
377 g_free(cco.filename);
378 return ret;
381 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
383 BlockDriver *drv;
384 Error *local_err = NULL;
385 int ret;
387 drv = bdrv_find_protocol(filename, true, errp);
388 if (drv == NULL) {
389 return -ENOENT;
392 ret = bdrv_create(drv, filename, opts, &local_err);
393 error_propagate(errp, local_err);
394 return ret;
398 * Try to get @bs's logical and physical block size.
399 * On success, store them in @bsz struct and return 0.
400 * On failure return -errno.
401 * @bs must not be empty.
403 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
405 BlockDriver *drv = bs->drv;
407 if (drv && drv->bdrv_probe_blocksizes) {
408 return drv->bdrv_probe_blocksizes(bs, bsz);
411 return -ENOTSUP;
415 * Try to get @bs's geometry (cyls, heads, sectors).
416 * On success, store them in @geo struct and return 0.
417 * On failure return -errno.
418 * @bs must not be empty.
420 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
422 BlockDriver *drv = bs->drv;
424 if (drv && drv->bdrv_probe_geometry) {
425 return drv->bdrv_probe_geometry(bs, geo);
428 return -ENOTSUP;
432 * Create a uniquely-named empty temporary file.
433 * Return 0 upon success, otherwise a negative errno value.
435 int get_tmp_filename(char *filename, int size)
437 #ifdef _WIN32
438 char temp_dir[MAX_PATH];
439 /* GetTempFileName requires that its output buffer (4th param)
440 have length MAX_PATH or greater. */
441 assert(size >= MAX_PATH);
442 return (GetTempPath(MAX_PATH, temp_dir)
443 && GetTempFileName(temp_dir, "qem", 0, filename)
444 ? 0 : -GetLastError());
445 #else
446 int fd;
447 const char *tmpdir;
448 tmpdir = getenv("TMPDIR");
449 if (!tmpdir) {
450 tmpdir = "/var/tmp";
452 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) {
453 return -EOVERFLOW;
455 fd = mkstemp(filename);
456 if (fd < 0) {
457 return -errno;
459 if (close(fd) != 0) {
460 unlink(filename);
461 return -errno;
463 return 0;
464 #endif
468 * Detect host devices. By convention, /dev/cdrom[N] is always
469 * recognized as a host CDROM.
471 static BlockDriver *find_hdev_driver(const char *filename)
473 int score_max = 0, score;
474 BlockDriver *drv = NULL, *d;
476 QLIST_FOREACH(d, &bdrv_drivers, list) {
477 if (d->bdrv_probe_device) {
478 score = d->bdrv_probe_device(filename);
479 if (score > score_max) {
480 score_max = score;
481 drv = d;
486 return drv;
489 static BlockDriver *bdrv_do_find_protocol(const char *protocol)
491 BlockDriver *drv1;
493 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
494 if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) {
495 return drv1;
499 return NULL;
502 BlockDriver *bdrv_find_protocol(const char *filename,
503 bool allow_protocol_prefix,
504 Error **errp)
506 BlockDriver *drv1;
507 char protocol[128];
508 int len;
509 const char *p;
510 int i;
512 /* TODO Drivers without bdrv_file_open must be specified explicitly */
515 * XXX(hch): we really should not let host device detection
516 * override an explicit protocol specification, but moving this
517 * later breaks access to device names with colons in them.
518 * Thanks to the brain-dead persistent naming schemes on udev-
519 * based Linux systems those actually are quite common.
521 drv1 = find_hdev_driver(filename);
522 if (drv1) {
523 return drv1;
526 if (!path_has_protocol(filename) || !allow_protocol_prefix) {
527 return &bdrv_file;
530 p = strchr(filename, ':');
531 assert(p != NULL);
532 len = p - filename;
533 if (len > sizeof(protocol) - 1)
534 len = sizeof(protocol) - 1;
535 memcpy(protocol, filename, len);
536 protocol[len] = '\0';
538 drv1 = bdrv_do_find_protocol(protocol);
539 if (drv1) {
540 return drv1;
543 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
544 if (block_driver_modules[i].protocol_name &&
545 !strcmp(block_driver_modules[i].protocol_name, protocol)) {
546 block_module_load_one(block_driver_modules[i].library_name);
547 break;
551 drv1 = bdrv_do_find_protocol(protocol);
552 if (!drv1) {
553 error_setg(errp, "Unknown protocol '%s'", protocol);
555 return drv1;
559 * Guess image format by probing its contents.
560 * This is not a good idea when your image is raw (CVE-2008-2004), but
561 * we do it anyway for backward compatibility.
563 * @buf contains the image's first @buf_size bytes.
564 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
565 * but can be smaller if the image file is smaller)
566 * @filename is its filename.
568 * For all block drivers, call the bdrv_probe() method to get its
569 * probing score.
570 * Return the first block driver with the highest probing score.
572 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
573 const char *filename)
575 int score_max = 0, score;
576 BlockDriver *drv = NULL, *d;
578 QLIST_FOREACH(d, &bdrv_drivers, list) {
579 if (d->bdrv_probe) {
580 score = d->bdrv_probe(buf, buf_size, filename);
581 if (score > score_max) {
582 score_max = score;
583 drv = d;
588 return drv;
591 static int find_image_format(BdrvChild *file, const char *filename,
592 BlockDriver **pdrv, Error **errp)
594 BlockDriverState *bs = file->bs;
595 BlockDriver *drv;
596 uint8_t buf[BLOCK_PROBE_BUF_SIZE];
597 int ret = 0;
599 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
600 if (bdrv_is_sg(bs) || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) {
601 *pdrv = &bdrv_raw;
602 return ret;
605 ret = bdrv_pread(file, 0, buf, sizeof(buf));
606 if (ret < 0) {
607 error_setg_errno(errp, -ret, "Could not read image for determining its "
608 "format");
609 *pdrv = NULL;
610 return ret;
613 drv = bdrv_probe_all(buf, ret, filename);
614 if (!drv) {
615 error_setg(errp, "Could not determine image format: No compatible "
616 "driver found");
617 ret = -ENOENT;
619 *pdrv = drv;
620 return ret;
624 * Set the current 'total_sectors' value
625 * Return 0 on success, -errno on error.
627 static int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
629 BlockDriver *drv = bs->drv;
631 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
632 if (bdrv_is_sg(bs))
633 return 0;
635 /* query actual device if possible, otherwise just trust the hint */
636 if (drv->bdrv_getlength) {
637 int64_t length = drv->bdrv_getlength(bs);
638 if (length < 0) {
639 return length;
641 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE);
644 bs->total_sectors = hint;
645 return 0;
649 * Combines a QDict of new block driver @options with any missing options taken
650 * from @old_options, so that leaving out an option defaults to its old value.
652 static void bdrv_join_options(BlockDriverState *bs, QDict *options,
653 QDict *old_options)
655 if (bs->drv && bs->drv->bdrv_join_options) {
656 bs->drv->bdrv_join_options(options, old_options);
657 } else {
658 qdict_join(options, old_options, false);
663 * Set open flags for a given discard mode
665 * Return 0 on success, -1 if the discard mode was invalid.
667 int bdrv_parse_discard_flags(const char *mode, int *flags)
669 *flags &= ~BDRV_O_UNMAP;
671 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) {
672 /* do nothing */
673 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) {
674 *flags |= BDRV_O_UNMAP;
675 } else {
676 return -1;
679 return 0;
683 * Set open flags for a given cache mode
685 * Return 0 on success, -1 if the cache mode was invalid.
687 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough)
689 *flags &= ~BDRV_O_CACHE_MASK;
691 if (!strcmp(mode, "off") || !strcmp(mode, "none")) {
692 *writethrough = false;
693 *flags |= BDRV_O_NOCACHE;
694 } else if (!strcmp(mode, "directsync")) {
695 *writethrough = true;
696 *flags |= BDRV_O_NOCACHE;
697 } else if (!strcmp(mode, "writeback")) {
698 *writethrough = false;
699 } else if (!strcmp(mode, "unsafe")) {
700 *writethrough = false;
701 *flags |= BDRV_O_NO_FLUSH;
702 } else if (!strcmp(mode, "writethrough")) {
703 *writethrough = true;
704 } else {
705 return -1;
708 return 0;
711 static void bdrv_child_cb_drained_begin(BdrvChild *child)
713 BlockDriverState *bs = child->opaque;
714 bdrv_drained_begin(bs);
717 static void bdrv_child_cb_drained_end(BdrvChild *child)
719 BlockDriverState *bs = child->opaque;
720 bdrv_drained_end(bs);
724 * Returns the options and flags that a temporary snapshot should get, based on
725 * the originally requested flags (the originally requested image will have
726 * flags like a backing file)
728 static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
729 int parent_flags, QDict *parent_options)
731 *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY;
733 /* For temporary files, unconditional cache=unsafe is fine */
734 qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off");
735 qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
737 /* Copy the read-only option from the parent */
738 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
740 /* aio=native doesn't work for cache.direct=off, so disable it for the
741 * temporary snapshot */
742 *child_flags &= ~BDRV_O_NATIVE_AIO;
746 * Returns the options and flags that bs->file should get if a protocol driver
747 * is expected, based on the given options and flags for the parent BDS
749 static void bdrv_inherited_options(int *child_flags, QDict *child_options,
750 int parent_flags, QDict *parent_options)
752 int flags = parent_flags;
754 /* Enable protocol handling, disable format probing for bs->file */
755 flags |= BDRV_O_PROTOCOL;
757 /* If the cache mode isn't explicitly set, inherit direct and no-flush from
758 * the parent. */
759 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
760 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
762 /* Inherit the read-only option from the parent if it's not set */
763 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
765 /* Our block drivers take care to send flushes and respect unmap policy,
766 * so we can default to enable both on lower layers regardless of the
767 * corresponding parent options. */
768 qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap");
770 /* Clear flags that only apply to the top layer */
771 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ |
772 BDRV_O_NO_IO);
774 *child_flags = flags;
777 const BdrvChildRole child_file = {
778 .inherit_options = bdrv_inherited_options,
779 .drained_begin = bdrv_child_cb_drained_begin,
780 .drained_end = bdrv_child_cb_drained_end,
784 * Returns the options and flags that bs->file should get if the use of formats
785 * (and not only protocols) is permitted for it, based on the given options and
786 * flags for the parent BDS
788 static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options,
789 int parent_flags, QDict *parent_options)
791 child_file.inherit_options(child_flags, child_options,
792 parent_flags, parent_options);
794 *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO);
797 const BdrvChildRole child_format = {
798 .inherit_options = bdrv_inherited_fmt_options,
799 .drained_begin = bdrv_child_cb_drained_begin,
800 .drained_end = bdrv_child_cb_drained_end,
804 * Returns the options and flags that bs->backing should get, based on the
805 * given options and flags for the parent BDS
807 static void bdrv_backing_options(int *child_flags, QDict *child_options,
808 int parent_flags, QDict *parent_options)
810 int flags = parent_flags;
812 /* The cache mode is inherited unmodified for backing files; except WCE,
813 * which is only applied on the top level (BlockBackend) */
814 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
815 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
817 /* backing files always opened read-only */
818 qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on");
819 flags &= ~BDRV_O_COPY_ON_READ;
821 /* snapshot=on is handled on the top layer */
822 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY);
824 *child_flags = flags;
827 static const BdrvChildRole child_backing = {
828 .inherit_options = bdrv_backing_options,
829 .drained_begin = bdrv_child_cb_drained_begin,
830 .drained_end = bdrv_child_cb_drained_end,
833 static int bdrv_open_flags(BlockDriverState *bs, int flags)
835 int open_flags = flags;
838 * Clear flags that are internal to the block layer before opening the
839 * image.
841 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL);
844 * Snapshots should be writable.
846 if (flags & BDRV_O_TEMPORARY) {
847 open_flags |= BDRV_O_RDWR;
850 return open_flags;
853 static void update_flags_from_options(int *flags, QemuOpts *opts)
855 *flags &= ~BDRV_O_CACHE_MASK;
857 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_NO_FLUSH));
858 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
859 *flags |= BDRV_O_NO_FLUSH;
862 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT));
863 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_DIRECT, false)) {
864 *flags |= BDRV_O_NOCACHE;
867 *flags &= ~BDRV_O_RDWR;
869 assert(qemu_opt_find(opts, BDRV_OPT_READ_ONLY));
870 if (!qemu_opt_get_bool(opts, BDRV_OPT_READ_ONLY, false)) {
871 *flags |= BDRV_O_RDWR;
876 static void update_options_from_flags(QDict *options, int flags)
878 if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) {
879 qdict_put(options, BDRV_OPT_CACHE_DIRECT,
880 qbool_from_bool(flags & BDRV_O_NOCACHE));
882 if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) {
883 qdict_put(options, BDRV_OPT_CACHE_NO_FLUSH,
884 qbool_from_bool(flags & BDRV_O_NO_FLUSH));
886 if (!qdict_haskey(options, BDRV_OPT_READ_ONLY)) {
887 qdict_put(options, BDRV_OPT_READ_ONLY,
888 qbool_from_bool(!(flags & BDRV_O_RDWR)));
892 static void bdrv_assign_node_name(BlockDriverState *bs,
893 const char *node_name,
894 Error **errp)
896 char *gen_node_name = NULL;
898 if (!node_name) {
899 node_name = gen_node_name = id_generate(ID_BLOCK);
900 } else if (!id_wellformed(node_name)) {
902 * Check for empty string or invalid characters, but not if it is
903 * generated (generated names use characters not available to the user)
905 error_setg(errp, "Invalid node name");
906 return;
909 /* takes care of avoiding namespaces collisions */
910 if (blk_by_name(node_name)) {
911 error_setg(errp, "node-name=%s is conflicting with a device id",
912 node_name);
913 goto out;
916 /* takes care of avoiding duplicates node names */
917 if (bdrv_find_node(node_name)) {
918 error_setg(errp, "Duplicate node name");
919 goto out;
922 /* copy node name into the bs and insert it into the graph list */
923 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
924 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
925 out:
926 g_free(gen_node_name);
929 QemuOptsList bdrv_runtime_opts = {
930 .name = "bdrv_common",
931 .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head),
932 .desc = {
934 .name = "node-name",
935 .type = QEMU_OPT_STRING,
936 .help = "Node name of the block device node",
939 .name = "driver",
940 .type = QEMU_OPT_STRING,
941 .help = "Block driver to use for the node",
944 .name = BDRV_OPT_CACHE_DIRECT,
945 .type = QEMU_OPT_BOOL,
946 .help = "Bypass software writeback cache on the host",
949 .name = BDRV_OPT_CACHE_NO_FLUSH,
950 .type = QEMU_OPT_BOOL,
951 .help = "Ignore flush requests",
954 .name = BDRV_OPT_READ_ONLY,
955 .type = QEMU_OPT_BOOL,
956 .help = "Node is opened in read-only mode",
959 .name = "detect-zeroes",
960 .type = QEMU_OPT_STRING,
961 .help = "try to optimize zero writes (off, on, unmap)",
964 .name = "discard",
965 .type = QEMU_OPT_STRING,
966 .help = "discard operation (ignore/off, unmap/on)",
968 { /* end of list */ }
973 * Common part for opening disk images and files
975 * Removes all processed options from *options.
977 static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file,
978 QDict *options, Error **errp)
980 int ret, open_flags;
981 const char *filename;
982 const char *driver_name = NULL;
983 const char *node_name = NULL;
984 const char *discard;
985 const char *detect_zeroes;
986 QemuOpts *opts;
987 BlockDriver *drv;
988 Error *local_err = NULL;
990 assert(bs->file == NULL);
991 assert(options != NULL && bs->options != options);
993 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
994 qemu_opts_absorb_qdict(opts, options, &local_err);
995 if (local_err) {
996 error_propagate(errp, local_err);
997 ret = -EINVAL;
998 goto fail_opts;
1001 update_flags_from_options(&bs->open_flags, opts);
1003 driver_name = qemu_opt_get(opts, "driver");
1004 drv = bdrv_find_format(driver_name);
1005 assert(drv != NULL);
1007 if (file != NULL) {
1008 filename = file->bs->filename;
1009 } else {
1010 filename = qdict_get_try_str(options, "filename");
1013 if (drv->bdrv_needs_filename && !filename) {
1014 error_setg(errp, "The '%s' block driver requires a file name",
1015 drv->format_name);
1016 ret = -EINVAL;
1017 goto fail_opts;
1020 trace_bdrv_open_common(bs, filename ?: "", bs->open_flags,
1021 drv->format_name);
1023 node_name = qemu_opt_get(opts, "node-name");
1024 bdrv_assign_node_name(bs, node_name, &local_err);
1025 if (local_err) {
1026 error_propagate(errp, local_err);
1027 ret = -EINVAL;
1028 goto fail_opts;
1031 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
1033 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
1034 error_setg(errp,
1035 !bs->read_only && bdrv_is_whitelisted(drv, true)
1036 ? "Driver '%s' can only be used for read-only devices"
1037 : "Driver '%s' is not whitelisted",
1038 drv->format_name);
1039 ret = -ENOTSUP;
1040 goto fail_opts;
1043 assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */
1044 if (bs->open_flags & BDRV_O_COPY_ON_READ) {
1045 if (!bs->read_only) {
1046 bdrv_enable_copy_on_read(bs);
1047 } else {
1048 error_setg(errp, "Can't use copy-on-read on read-only device");
1049 ret = -EINVAL;
1050 goto fail_opts;
1054 discard = qemu_opt_get(opts, "discard");
1055 if (discard != NULL) {
1056 if (bdrv_parse_discard_flags(discard, &bs->open_flags) != 0) {
1057 error_setg(errp, "Invalid discard option");
1058 ret = -EINVAL;
1059 goto fail_opts;
1063 detect_zeroes = qemu_opt_get(opts, "detect-zeroes");
1064 if (detect_zeroes) {
1065 BlockdevDetectZeroesOptions value =
1066 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
1067 detect_zeroes,
1068 BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX,
1069 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
1070 &local_err);
1071 if (local_err) {
1072 error_propagate(errp, local_err);
1073 ret = -EINVAL;
1074 goto fail_opts;
1077 if (value == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
1078 !(bs->open_flags & BDRV_O_UNMAP))
1080 error_setg(errp, "setting detect-zeroes to unmap is not allowed "
1081 "without setting discard operation to unmap");
1082 ret = -EINVAL;
1083 goto fail_opts;
1086 bs->detect_zeroes = value;
1089 if (filename != NULL) {
1090 pstrcpy(bs->filename, sizeof(bs->filename), filename);
1091 } else {
1092 bs->filename[0] = '\0';
1094 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename);
1096 bs->drv = drv;
1097 bs->opaque = g_malloc0(drv->instance_size);
1099 /* Open the image, either directly or using a protocol */
1100 open_flags = bdrv_open_flags(bs, bs->open_flags);
1101 if (drv->bdrv_file_open) {
1102 assert(file == NULL);
1103 assert(!drv->bdrv_needs_filename || filename != NULL);
1104 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err);
1105 } else {
1106 if (file == NULL) {
1107 error_setg(errp, "Can't use '%s' as a block driver for the "
1108 "protocol level", drv->format_name);
1109 ret = -EINVAL;
1110 goto free_and_fail;
1112 bs->file = file;
1113 ret = drv->bdrv_open(bs, options, open_flags, &local_err);
1116 if (ret < 0) {
1117 if (local_err) {
1118 error_propagate(errp, local_err);
1119 } else if (bs->filename[0]) {
1120 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename);
1121 } else {
1122 error_setg_errno(errp, -ret, "Could not open image");
1124 goto free_and_fail;
1127 ret = refresh_total_sectors(bs, bs->total_sectors);
1128 if (ret < 0) {
1129 error_setg_errno(errp, -ret, "Could not refresh total sector count");
1130 goto free_and_fail;
1133 bdrv_refresh_limits(bs, &local_err);
1134 if (local_err) {
1135 error_propagate(errp, local_err);
1136 ret = -EINVAL;
1137 goto free_and_fail;
1140 assert(bdrv_opt_mem_align(bs) != 0);
1141 assert(bdrv_min_mem_align(bs) != 0);
1142 assert(is_power_of_2(bs->bl.request_alignment));
1144 qemu_opts_del(opts);
1145 return 0;
1147 free_and_fail:
1148 bs->file = NULL;
1149 g_free(bs->opaque);
1150 bs->opaque = NULL;
1151 bs->drv = NULL;
1152 fail_opts:
1153 qemu_opts_del(opts);
1154 return ret;
1157 static QDict *parse_json_filename(const char *filename, Error **errp)
1159 QObject *options_obj;
1160 QDict *options;
1161 int ret;
1163 ret = strstart(filename, "json:", &filename);
1164 assert(ret);
1166 options_obj = qobject_from_json(filename);
1167 if (!options_obj) {
1168 error_setg(errp, "Could not parse the JSON options");
1169 return NULL;
1172 if (qobject_type(options_obj) != QTYPE_QDICT) {
1173 qobject_decref(options_obj);
1174 error_setg(errp, "Invalid JSON object given");
1175 return NULL;
1178 options = qobject_to_qdict(options_obj);
1179 qdict_flatten(options);
1181 return options;
1184 static void parse_json_protocol(QDict *options, const char **pfilename,
1185 Error **errp)
1187 QDict *json_options;
1188 Error *local_err = NULL;
1190 /* Parse json: pseudo-protocol */
1191 if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) {
1192 return;
1195 json_options = parse_json_filename(*pfilename, &local_err);
1196 if (local_err) {
1197 error_propagate(errp, local_err);
1198 return;
1201 /* Options given in the filename have lower priority than options
1202 * specified directly */
1203 qdict_join(options, json_options, false);
1204 QDECREF(json_options);
1205 *pfilename = NULL;
1209 * Fills in default options for opening images and converts the legacy
1210 * filename/flags pair to option QDict entries.
1211 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1212 * block driver has been specified explicitly.
1214 static int bdrv_fill_options(QDict **options, const char *filename,
1215 int *flags, Error **errp)
1217 const char *drvname;
1218 bool protocol = *flags & BDRV_O_PROTOCOL;
1219 bool parse_filename = false;
1220 BlockDriver *drv = NULL;
1221 Error *local_err = NULL;
1223 drvname = qdict_get_try_str(*options, "driver");
1224 if (drvname) {
1225 drv = bdrv_find_format(drvname);
1226 if (!drv) {
1227 error_setg(errp, "Unknown driver '%s'", drvname);
1228 return -ENOENT;
1230 /* If the user has explicitly specified the driver, this choice should
1231 * override the BDRV_O_PROTOCOL flag */
1232 protocol = drv->bdrv_file_open;
1235 if (protocol) {
1236 *flags |= BDRV_O_PROTOCOL;
1237 } else {
1238 *flags &= ~BDRV_O_PROTOCOL;
1241 /* Translate cache options from flags into options */
1242 update_options_from_flags(*options, *flags);
1244 /* Fetch the file name from the options QDict if necessary */
1245 if (protocol && filename) {
1246 if (!qdict_haskey(*options, "filename")) {
1247 qdict_put(*options, "filename", qstring_from_str(filename));
1248 parse_filename = true;
1249 } else {
1250 error_setg(errp, "Can't specify 'file' and 'filename' options at "
1251 "the same time");
1252 return -EINVAL;
1256 /* Find the right block driver */
1257 filename = qdict_get_try_str(*options, "filename");
1259 if (!drvname && protocol) {
1260 if (filename) {
1261 drv = bdrv_find_protocol(filename, parse_filename, errp);
1262 if (!drv) {
1263 return -EINVAL;
1266 drvname = drv->format_name;
1267 qdict_put(*options, "driver", qstring_from_str(drvname));
1268 } else {
1269 error_setg(errp, "Must specify either driver or file");
1270 return -EINVAL;
1274 assert(drv || !protocol);
1276 /* Driver-specific filename parsing */
1277 if (drv && drv->bdrv_parse_filename && parse_filename) {
1278 drv->bdrv_parse_filename(filename, *options, &local_err);
1279 if (local_err) {
1280 error_propagate(errp, local_err);
1281 return -EINVAL;
1284 if (!drv->bdrv_needs_filename) {
1285 qdict_del(*options, "filename");
1289 return 0;
1292 static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
1294 BlockDriverState *old_bs = child->bs;
1296 if (old_bs) {
1297 if (old_bs->quiesce_counter && child->role->drained_end) {
1298 child->role->drained_end(child);
1300 QLIST_REMOVE(child, next_parent);
1303 child->bs = new_bs;
1305 if (new_bs) {
1306 QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
1307 if (new_bs->quiesce_counter && child->role->drained_begin) {
1308 child->role->drained_begin(child);
1313 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
1314 const char *child_name,
1315 const BdrvChildRole *child_role,
1316 void *opaque)
1318 BdrvChild *child = g_new(BdrvChild, 1);
1319 *child = (BdrvChild) {
1320 .bs = NULL,
1321 .name = g_strdup(child_name),
1322 .role = child_role,
1323 .opaque = opaque,
1326 bdrv_replace_child(child, child_bs);
1328 return child;
1331 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
1332 BlockDriverState *child_bs,
1333 const char *child_name,
1334 const BdrvChildRole *child_role)
1336 BdrvChild *child = bdrv_root_attach_child(child_bs, child_name, child_role,
1337 parent_bs);
1338 QLIST_INSERT_HEAD(&parent_bs->children, child, next);
1339 return child;
1342 static void bdrv_detach_child(BdrvChild *child)
1344 if (child->next.le_prev) {
1345 QLIST_REMOVE(child, next);
1346 child->next.le_prev = NULL;
1349 bdrv_replace_child(child, NULL);
1351 g_free(child->name);
1352 g_free(child);
1355 void bdrv_root_unref_child(BdrvChild *child)
1357 BlockDriverState *child_bs;
1359 child_bs = child->bs;
1360 bdrv_detach_child(child);
1361 bdrv_unref(child_bs);
1364 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child)
1366 if (child == NULL) {
1367 return;
1370 if (child->bs->inherits_from == parent) {
1371 child->bs->inherits_from = NULL;
1374 bdrv_root_unref_child(child);
1378 static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load)
1380 BdrvChild *c;
1381 QLIST_FOREACH(c, &bs->parents, next_parent) {
1382 if (c->role->change_media) {
1383 c->role->change_media(c, load);
1388 static void bdrv_parent_cb_resize(BlockDriverState *bs)
1390 BdrvChild *c;
1391 QLIST_FOREACH(c, &bs->parents, next_parent) {
1392 if (c->role->resize) {
1393 c->role->resize(c);
1399 * Sets the backing file link of a BDS. A new reference is created; callers
1400 * which don't need their own reference any more must call bdrv_unref().
1402 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd)
1404 if (backing_hd) {
1405 bdrv_ref(backing_hd);
1408 if (bs->backing) {
1409 assert(bs->backing_blocker);
1410 bdrv_op_unblock_all(bs->backing->bs, bs->backing_blocker);
1411 bdrv_unref_child(bs, bs->backing);
1412 } else if (backing_hd) {
1413 error_setg(&bs->backing_blocker,
1414 "node is used as backing hd of '%s'",
1415 bdrv_get_device_or_node_name(bs));
1418 if (!backing_hd) {
1419 error_free(bs->backing_blocker);
1420 bs->backing_blocker = NULL;
1421 bs->backing = NULL;
1422 goto out;
1424 bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing);
1425 bs->open_flags &= ~BDRV_O_NO_BACKING;
1426 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_hd->filename);
1427 pstrcpy(bs->backing_format, sizeof(bs->backing_format),
1428 backing_hd->drv ? backing_hd->drv->format_name : "");
1430 bdrv_op_block_all(backing_hd, bs->backing_blocker);
1431 /* Otherwise we won't be able to commit due to check in bdrv_commit */
1432 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,
1433 bs->backing_blocker);
1435 * We do backup in 3 ways:
1436 * 1. drive backup
1437 * The target bs is new opened, and the source is top BDS
1438 * 2. blockdev backup
1439 * Both the source and the target are top BDSes.
1440 * 3. internal backup(used for block replication)
1441 * Both the source and the target are backing file
1443 * In case 1 and 2, neither the source nor the target is the backing file.
1444 * In case 3, we will block the top BDS, so there is only one block job
1445 * for the top BDS and its backing chain.
1447 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_SOURCE,
1448 bs->backing_blocker);
1449 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_TARGET,
1450 bs->backing_blocker);
1451 out:
1452 bdrv_refresh_limits(bs, NULL);
1456 * Opens the backing file for a BlockDriverState if not yet open
1458 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
1459 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
1460 * itself, all options starting with "${bdref_key}." are considered part of the
1461 * BlockdevRef.
1463 * TODO Can this be unified with bdrv_open_image()?
1465 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
1466 const char *bdref_key, Error **errp)
1468 char *backing_filename = g_malloc0(PATH_MAX);
1469 char *bdref_key_dot;
1470 const char *reference = NULL;
1471 int ret = 0;
1472 BlockDriverState *backing_hd;
1473 QDict *options;
1474 QDict *tmp_parent_options = NULL;
1475 Error *local_err = NULL;
1477 if (bs->backing != NULL) {
1478 goto free_exit;
1481 /* NULL means an empty set of options */
1482 if (parent_options == NULL) {
1483 tmp_parent_options = qdict_new();
1484 parent_options = tmp_parent_options;
1487 bs->open_flags &= ~BDRV_O_NO_BACKING;
1489 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
1490 qdict_extract_subqdict(parent_options, &options, bdref_key_dot);
1491 g_free(bdref_key_dot);
1493 reference = qdict_get_try_str(parent_options, bdref_key);
1494 if (reference || qdict_haskey(options, "file.filename")) {
1495 backing_filename[0] = '\0';
1496 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
1497 QDECREF(options);
1498 goto free_exit;
1499 } else {
1500 bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX,
1501 &local_err);
1502 if (local_err) {
1503 ret = -EINVAL;
1504 error_propagate(errp, local_err);
1505 QDECREF(options);
1506 goto free_exit;
1510 if (!bs->drv || !bs->drv->supports_backing) {
1511 ret = -EINVAL;
1512 error_setg(errp, "Driver doesn't support backing files");
1513 QDECREF(options);
1514 goto free_exit;
1517 if (bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) {
1518 qdict_put(options, "driver", qstring_from_str(bs->backing_format));
1521 backing_hd = bdrv_open_inherit(*backing_filename ? backing_filename : NULL,
1522 reference, options, 0, bs, &child_backing,
1523 errp);
1524 if (!backing_hd) {
1525 bs->open_flags |= BDRV_O_NO_BACKING;
1526 error_prepend(errp, "Could not open backing file: ");
1527 ret = -EINVAL;
1528 goto free_exit;
1531 /* Hook up the backing file link; drop our reference, bs owns the
1532 * backing_hd reference now */
1533 bdrv_set_backing_hd(bs, backing_hd);
1534 bdrv_unref(backing_hd);
1536 qdict_del(parent_options, bdref_key);
1538 free_exit:
1539 g_free(backing_filename);
1540 QDECREF(tmp_parent_options);
1541 return ret;
1545 * Opens a disk image whose options are given as BlockdevRef in another block
1546 * device's options.
1548 * If allow_none is true, no image will be opened if filename is false and no
1549 * BlockdevRef is given. NULL will be returned, but errp remains unset.
1551 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
1552 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
1553 * itself, all options starting with "${bdref_key}." are considered part of the
1554 * BlockdevRef.
1556 * The BlockdevRef will be removed from the options QDict.
1558 BdrvChild *bdrv_open_child(const char *filename,
1559 QDict *options, const char *bdref_key,
1560 BlockDriverState* parent,
1561 const BdrvChildRole *child_role,
1562 bool allow_none, Error **errp)
1564 BdrvChild *c = NULL;
1565 BlockDriverState *bs;
1566 QDict *image_options;
1567 char *bdref_key_dot;
1568 const char *reference;
1570 assert(child_role != NULL);
1572 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
1573 qdict_extract_subqdict(options, &image_options, bdref_key_dot);
1574 g_free(bdref_key_dot);
1576 reference = qdict_get_try_str(options, bdref_key);
1577 if (!filename && !reference && !qdict_size(image_options)) {
1578 if (!allow_none) {
1579 error_setg(errp, "A block device must be specified for \"%s\"",
1580 bdref_key);
1582 QDECREF(image_options);
1583 goto done;
1586 bs = bdrv_open_inherit(filename, reference, image_options, 0,
1587 parent, child_role, errp);
1588 if (!bs) {
1589 goto done;
1592 c = bdrv_attach_child(parent, bs, bdref_key, child_role);
1594 done:
1595 qdict_del(options, bdref_key);
1596 return c;
1599 static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
1600 int flags,
1601 QDict *snapshot_options,
1602 Error **errp)
1604 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
1605 char *tmp_filename = g_malloc0(PATH_MAX + 1);
1606 int64_t total_size;
1607 QemuOpts *opts = NULL;
1608 BlockDriverState *bs_snapshot;
1609 int ret;
1611 /* if snapshot, we create a temporary backing file and open it
1612 instead of opening 'filename' directly */
1614 /* Get the required size from the image */
1615 total_size = bdrv_getlength(bs);
1616 if (total_size < 0) {
1617 error_setg_errno(errp, -total_size, "Could not get image size");
1618 goto out;
1621 /* Create the temporary image */
1622 ret = get_tmp_filename(tmp_filename, PATH_MAX + 1);
1623 if (ret < 0) {
1624 error_setg_errno(errp, -ret, "Could not get temporary filename");
1625 goto out;
1628 opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0,
1629 &error_abort);
1630 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort);
1631 ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp);
1632 qemu_opts_del(opts);
1633 if (ret < 0) {
1634 error_prepend(errp, "Could not create temporary overlay '%s': ",
1635 tmp_filename);
1636 goto out;
1639 /* Prepare options QDict for the temporary file */
1640 qdict_put(snapshot_options, "file.driver",
1641 qstring_from_str("file"));
1642 qdict_put(snapshot_options, "file.filename",
1643 qstring_from_str(tmp_filename));
1644 qdict_put(snapshot_options, "driver",
1645 qstring_from_str("qcow2"));
1647 bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp);
1648 snapshot_options = NULL;
1649 if (!bs_snapshot) {
1650 ret = -EINVAL;
1651 goto out;
1654 /* bdrv_append() consumes a strong reference to bs_snapshot (i.e. it will
1655 * call bdrv_unref() on it), so in order to be able to return one, we have
1656 * to increase bs_snapshot's refcount here */
1657 bdrv_ref(bs_snapshot);
1658 bdrv_append(bs_snapshot, bs);
1660 g_free(tmp_filename);
1661 return bs_snapshot;
1663 out:
1664 QDECREF(snapshot_options);
1665 g_free(tmp_filename);
1666 return NULL;
1670 * Opens a disk image (raw, qcow2, vmdk, ...)
1672 * options is a QDict of options to pass to the block drivers, or NULL for an
1673 * empty set of options. The reference to the QDict belongs to the block layer
1674 * after the call (even on failure), so if the caller intends to reuse the
1675 * dictionary, it needs to use QINCREF() before calling bdrv_open.
1677 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
1678 * If it is not NULL, the referenced BDS will be reused.
1680 * The reference parameter may be used to specify an existing block device which
1681 * should be opened. If specified, neither options nor a filename may be given,
1682 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
1684 static BlockDriverState *bdrv_open_inherit(const char *filename,
1685 const char *reference,
1686 QDict *options, int flags,
1687 BlockDriverState *parent,
1688 const BdrvChildRole *child_role,
1689 Error **errp)
1691 int ret;
1692 BdrvChild *file = NULL;
1693 BlockDriverState *bs;
1694 BlockDriver *drv = NULL;
1695 const char *drvname;
1696 const char *backing;
1697 Error *local_err = NULL;
1698 QDict *snapshot_options = NULL;
1699 int snapshot_flags = 0;
1701 assert(!child_role || !flags);
1702 assert(!child_role == !parent);
1704 if (reference) {
1705 bool options_non_empty = options ? qdict_size(options) : false;
1706 QDECREF(options);
1708 if (filename || options_non_empty) {
1709 error_setg(errp, "Cannot reference an existing block device with "
1710 "additional options or a new filename");
1711 return NULL;
1714 bs = bdrv_lookup_bs(reference, reference, errp);
1715 if (!bs) {
1716 return NULL;
1719 bdrv_ref(bs);
1720 return bs;
1723 bs = bdrv_new();
1725 /* NULL means an empty set of options */
1726 if (options == NULL) {
1727 options = qdict_new();
1730 /* json: syntax counts as explicit options, as if in the QDict */
1731 parse_json_protocol(options, &filename, &local_err);
1732 if (local_err) {
1733 goto fail;
1736 bs->explicit_options = qdict_clone_shallow(options);
1738 if (child_role) {
1739 bs->inherits_from = parent;
1740 child_role->inherit_options(&flags, options,
1741 parent->open_flags, parent->options);
1744 ret = bdrv_fill_options(&options, filename, &flags, &local_err);
1745 if (local_err) {
1746 goto fail;
1749 /* Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
1750 * FIXME: we're parsing the QDict to avoid having to create a
1751 * QemuOpts just for this, but neither option is optimal. */
1752 if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") &&
1753 !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) {
1754 flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR);
1755 } else {
1756 flags &= ~BDRV_O_RDWR;
1759 if (flags & BDRV_O_SNAPSHOT) {
1760 snapshot_options = qdict_new();
1761 bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options,
1762 flags, options);
1763 /* Let bdrv_backing_options() override "read-only" */
1764 qdict_del(options, BDRV_OPT_READ_ONLY);
1765 bdrv_backing_options(&flags, options, flags, options);
1768 bs->open_flags = flags;
1769 bs->options = options;
1770 options = qdict_clone_shallow(options);
1772 /* Find the right image format driver */
1773 drvname = qdict_get_try_str(options, "driver");
1774 if (drvname) {
1775 drv = bdrv_find_format(drvname);
1776 if (!drv) {
1777 error_setg(errp, "Unknown driver: '%s'", drvname);
1778 goto fail;
1782 assert(drvname || !(flags & BDRV_O_PROTOCOL));
1784 backing = qdict_get_try_str(options, "backing");
1785 if (backing && *backing == '\0') {
1786 flags |= BDRV_O_NO_BACKING;
1787 qdict_del(options, "backing");
1790 /* Open image file without format layer */
1791 if ((flags & BDRV_O_PROTOCOL) == 0) {
1792 file = bdrv_open_child(filename, options, "file", bs,
1793 &child_file, true, &local_err);
1794 if (local_err) {
1795 goto fail;
1799 /* Image format probing */
1800 bs->probed = !drv;
1801 if (!drv && file) {
1802 ret = find_image_format(file, filename, &drv, &local_err);
1803 if (ret < 0) {
1804 goto fail;
1807 * This option update would logically belong in bdrv_fill_options(),
1808 * but we first need to open bs->file for the probing to work, while
1809 * opening bs->file already requires the (mostly) final set of options
1810 * so that cache mode etc. can be inherited.
1812 * Adding the driver later is somewhat ugly, but it's not an option
1813 * that would ever be inherited, so it's correct. We just need to make
1814 * sure to update both bs->options (which has the full effective
1815 * options for bs) and options (which has file.* already removed).
1817 qdict_put(bs->options, "driver", qstring_from_str(drv->format_name));
1818 qdict_put(options, "driver", qstring_from_str(drv->format_name));
1819 } else if (!drv) {
1820 error_setg(errp, "Must specify either driver or file");
1821 goto fail;
1824 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
1825 assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open);
1826 /* file must be NULL if a protocol BDS is about to be created
1827 * (the inverse results in an error message from bdrv_open_common()) */
1828 assert(!(flags & BDRV_O_PROTOCOL) || !file);
1830 /* Open the image */
1831 ret = bdrv_open_common(bs, file, options, &local_err);
1832 if (ret < 0) {
1833 goto fail;
1836 if (file && (bs->file != file)) {
1837 bdrv_unref_child(bs, file);
1838 file = NULL;
1841 /* If there is a backing file, use it */
1842 if ((flags & BDRV_O_NO_BACKING) == 0) {
1843 ret = bdrv_open_backing_file(bs, options, "backing", &local_err);
1844 if (ret < 0) {
1845 goto close_and_fail;
1849 bdrv_refresh_filename(bs);
1851 /* Check if any unknown options were used */
1852 if (options && (qdict_size(options) != 0)) {
1853 const QDictEntry *entry = qdict_first(options);
1854 if (flags & BDRV_O_PROTOCOL) {
1855 error_setg(errp, "Block protocol '%s' doesn't support the option "
1856 "'%s'", drv->format_name, entry->key);
1857 } else {
1858 error_setg(errp,
1859 "Block format '%s' does not support the option '%s'",
1860 drv->format_name, entry->key);
1863 goto close_and_fail;
1866 if (!bdrv_key_required(bs)) {
1867 bdrv_parent_cb_change_media(bs, true);
1868 } else if (!runstate_check(RUN_STATE_PRELAUNCH)
1869 && !runstate_check(RUN_STATE_INMIGRATE)
1870 && !runstate_check(RUN_STATE_PAUSED)) { /* HACK */
1871 error_setg(errp,
1872 "Guest must be stopped for opening of encrypted image");
1873 goto close_and_fail;
1876 QDECREF(options);
1878 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
1879 * temporary snapshot afterwards. */
1880 if (snapshot_flags) {
1881 BlockDriverState *snapshot_bs;
1882 snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags,
1883 snapshot_options, &local_err);
1884 snapshot_options = NULL;
1885 if (local_err) {
1886 goto close_and_fail;
1888 /* We are not going to return bs but the overlay on top of it
1889 * (snapshot_bs); thus, we have to drop the strong reference to bs
1890 * (which we obtained by calling bdrv_new()). bs will not be deleted,
1891 * though, because the overlay still has a reference to it. */
1892 bdrv_unref(bs);
1893 bs = snapshot_bs;
1896 return bs;
1898 fail:
1899 if (file != NULL) {
1900 bdrv_unref_child(bs, file);
1902 QDECREF(snapshot_options);
1903 QDECREF(bs->explicit_options);
1904 QDECREF(bs->options);
1905 QDECREF(options);
1906 bs->options = NULL;
1907 bdrv_unref(bs);
1908 error_propagate(errp, local_err);
1909 return NULL;
1911 close_and_fail:
1912 bdrv_unref(bs);
1913 QDECREF(snapshot_options);
1914 QDECREF(options);
1915 error_propagate(errp, local_err);
1916 return NULL;
1919 BlockDriverState *bdrv_open(const char *filename, const char *reference,
1920 QDict *options, int flags, Error **errp)
1922 return bdrv_open_inherit(filename, reference, options, flags, NULL,
1923 NULL, errp);
1926 typedef struct BlockReopenQueueEntry {
1927 bool prepared;
1928 BDRVReopenState state;
1929 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry;
1930 } BlockReopenQueueEntry;
1933 * Adds a BlockDriverState to a simple queue for an atomic, transactional
1934 * reopen of multiple devices.
1936 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT
1937 * already performed, or alternatively may be NULL a new BlockReopenQueue will
1938 * be created and initialized. This newly created BlockReopenQueue should be
1939 * passed back in for subsequent calls that are intended to be of the same
1940 * atomic 'set'.
1942 * bs is the BlockDriverState to add to the reopen queue.
1944 * options contains the changed options for the associated bs
1945 * (the BlockReopenQueue takes ownership)
1947 * flags contains the open flags for the associated bs
1949 * returns a pointer to bs_queue, which is either the newly allocated
1950 * bs_queue, or the existing bs_queue being used.
1953 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
1954 BlockDriverState *bs,
1955 QDict *options,
1956 int flags,
1957 const BdrvChildRole *role,
1958 QDict *parent_options,
1959 int parent_flags)
1961 assert(bs != NULL);
1963 BlockReopenQueueEntry *bs_entry;
1964 BdrvChild *child;
1965 QDict *old_options, *explicit_options;
1967 if (bs_queue == NULL) {
1968 bs_queue = g_new0(BlockReopenQueue, 1);
1969 QSIMPLEQ_INIT(bs_queue);
1972 if (!options) {
1973 options = qdict_new();
1976 /* Check if this BlockDriverState is already in the queue */
1977 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
1978 if (bs == bs_entry->state.bs) {
1979 break;
1984 * Precedence of options:
1985 * 1. Explicitly passed in options (highest)
1986 * 2. Set in flags (only for top level)
1987 * 3. Retained from explicitly set options of bs
1988 * 4. Inherited from parent node
1989 * 5. Retained from effective options of bs
1992 if (!parent_options) {
1994 * Any setting represented by flags is always updated. If the
1995 * corresponding QDict option is set, it takes precedence. Otherwise
1996 * the flag is translated into a QDict option. The old setting of bs is
1997 * not considered.
1999 update_options_from_flags(options, flags);
2002 /* Old explicitly set values (don't overwrite by inherited value) */
2003 if (bs_entry) {
2004 old_options = qdict_clone_shallow(bs_entry->state.explicit_options);
2005 } else {
2006 old_options = qdict_clone_shallow(bs->explicit_options);
2008 bdrv_join_options(bs, options, old_options);
2009 QDECREF(old_options);
2011 explicit_options = qdict_clone_shallow(options);
2013 /* Inherit from parent node */
2014 if (parent_options) {
2015 assert(!flags);
2016 role->inherit_options(&flags, options, parent_flags, parent_options);
2019 /* Old values are used for options that aren't set yet */
2020 old_options = qdict_clone_shallow(bs->options);
2021 bdrv_join_options(bs, options, old_options);
2022 QDECREF(old_options);
2024 /* bdrv_open() masks this flag out */
2025 flags &= ~BDRV_O_PROTOCOL;
2027 QLIST_FOREACH(child, &bs->children, next) {
2028 QDict *new_child_options;
2029 char *child_key_dot;
2031 /* reopen can only change the options of block devices that were
2032 * implicitly created and inherited options. For other (referenced)
2033 * block devices, a syntax like "backing.foo" results in an error. */
2034 if (child->bs->inherits_from != bs) {
2035 continue;
2038 child_key_dot = g_strdup_printf("%s.", child->name);
2039 qdict_extract_subqdict(options, &new_child_options, child_key_dot);
2040 g_free(child_key_dot);
2042 bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options, 0,
2043 child->role, options, flags);
2046 if (!bs_entry) {
2047 bs_entry = g_new0(BlockReopenQueueEntry, 1);
2048 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry);
2049 } else {
2050 QDECREF(bs_entry->state.options);
2051 QDECREF(bs_entry->state.explicit_options);
2054 bs_entry->state.bs = bs;
2055 bs_entry->state.options = options;
2056 bs_entry->state.explicit_options = explicit_options;
2057 bs_entry->state.flags = flags;
2059 return bs_queue;
2062 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
2063 BlockDriverState *bs,
2064 QDict *options, int flags)
2066 return bdrv_reopen_queue_child(bs_queue, bs, options, flags,
2067 NULL, NULL, 0);
2071 * Reopen multiple BlockDriverStates atomically & transactionally.
2073 * The queue passed in (bs_queue) must have been built up previous
2074 * via bdrv_reopen_queue().
2076 * Reopens all BDS specified in the queue, with the appropriate
2077 * flags. All devices are prepared for reopen, and failure of any
2078 * device will cause all device changes to be abandonded, and intermediate
2079 * data cleaned up.
2081 * If all devices prepare successfully, then the changes are committed
2082 * to all devices.
2085 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
2087 int ret = -1;
2088 BlockReopenQueueEntry *bs_entry, *next;
2089 Error *local_err = NULL;
2091 assert(bs_queue != NULL);
2093 bdrv_drain_all();
2095 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
2096 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) {
2097 error_propagate(errp, local_err);
2098 goto cleanup;
2100 bs_entry->prepared = true;
2103 /* If we reach this point, we have success and just need to apply the
2104 * changes
2106 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
2107 bdrv_reopen_commit(&bs_entry->state);
2110 ret = 0;
2112 cleanup:
2113 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
2114 if (ret && bs_entry->prepared) {
2115 bdrv_reopen_abort(&bs_entry->state);
2116 } else if (ret) {
2117 QDECREF(bs_entry->state.explicit_options);
2119 QDECREF(bs_entry->state.options);
2120 g_free(bs_entry);
2122 g_free(bs_queue);
2123 return ret;
2127 /* Reopen a single BlockDriverState with the specified flags. */
2128 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp)
2130 int ret = -1;
2131 Error *local_err = NULL;
2132 BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags);
2134 ret = bdrv_reopen_multiple(queue, &local_err);
2135 if (local_err != NULL) {
2136 error_propagate(errp, local_err);
2138 return ret;
2143 * Prepares a BlockDriverState for reopen. All changes are staged in the
2144 * 'opaque' field of the BDRVReopenState, which is used and allocated by
2145 * the block driver layer .bdrv_reopen_prepare()
2147 * bs is the BlockDriverState to reopen
2148 * flags are the new open flags
2149 * queue is the reopen queue
2151 * Returns 0 on success, non-zero on error. On error errp will be set
2152 * as well.
2154 * On failure, bdrv_reopen_abort() will be called to clean up any data.
2155 * It is the responsibility of the caller to then call the abort() or
2156 * commit() for any other BDS that have been left in a prepare() state
2159 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
2160 Error **errp)
2162 int ret = -1;
2163 Error *local_err = NULL;
2164 BlockDriver *drv;
2165 QemuOpts *opts;
2166 const char *value;
2168 assert(reopen_state != NULL);
2169 assert(reopen_state->bs->drv != NULL);
2170 drv = reopen_state->bs->drv;
2172 /* Process generic block layer options */
2173 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
2174 qemu_opts_absorb_qdict(opts, reopen_state->options, &local_err);
2175 if (local_err) {
2176 error_propagate(errp, local_err);
2177 ret = -EINVAL;
2178 goto error;
2181 update_flags_from_options(&reopen_state->flags, opts);
2183 /* node-name and driver must be unchanged. Put them back into the QDict, so
2184 * that they are checked at the end of this function. */
2185 value = qemu_opt_get(opts, "node-name");
2186 if (value) {
2187 qdict_put(reopen_state->options, "node-name", qstring_from_str(value));
2190 value = qemu_opt_get(opts, "driver");
2191 if (value) {
2192 qdict_put(reopen_state->options, "driver", qstring_from_str(value));
2195 /* if we are to stay read-only, do not allow permission change
2196 * to r/w */
2197 if (!(reopen_state->bs->open_flags & BDRV_O_ALLOW_RDWR) &&
2198 reopen_state->flags & BDRV_O_RDWR) {
2199 error_setg(errp, "Node '%s' is read only",
2200 bdrv_get_device_or_node_name(reopen_state->bs));
2201 goto error;
2205 ret = bdrv_flush(reopen_state->bs);
2206 if (ret) {
2207 error_setg_errno(errp, -ret, "Error flushing drive");
2208 goto error;
2211 if (drv->bdrv_reopen_prepare) {
2212 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err);
2213 if (ret) {
2214 if (local_err != NULL) {
2215 error_propagate(errp, local_err);
2216 } else {
2217 error_setg(errp, "failed while preparing to reopen image '%s'",
2218 reopen_state->bs->filename);
2220 goto error;
2222 } else {
2223 /* It is currently mandatory to have a bdrv_reopen_prepare()
2224 * handler for each supported drv. */
2225 error_setg(errp, "Block format '%s' used by node '%s' "
2226 "does not support reopening files", drv->format_name,
2227 bdrv_get_device_or_node_name(reopen_state->bs));
2228 ret = -1;
2229 goto error;
2232 /* Options that are not handled are only okay if they are unchanged
2233 * compared to the old state. It is expected that some options are only
2234 * used for the initial open, but not reopen (e.g. filename) */
2235 if (qdict_size(reopen_state->options)) {
2236 const QDictEntry *entry = qdict_first(reopen_state->options);
2238 do {
2239 QString *new_obj = qobject_to_qstring(entry->value);
2240 const char *new = qstring_get_str(new_obj);
2241 const char *old = qdict_get_try_str(reopen_state->bs->options,
2242 entry->key);
2244 if (!old || strcmp(new, old)) {
2245 error_setg(errp, "Cannot change the option '%s'", entry->key);
2246 ret = -EINVAL;
2247 goto error;
2249 } while ((entry = qdict_next(reopen_state->options, entry)));
2252 ret = 0;
2254 error:
2255 qemu_opts_del(opts);
2256 return ret;
2260 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
2261 * makes them final by swapping the staging BlockDriverState contents into
2262 * the active BlockDriverState contents.
2264 void bdrv_reopen_commit(BDRVReopenState *reopen_state)
2266 BlockDriver *drv;
2268 assert(reopen_state != NULL);
2269 drv = reopen_state->bs->drv;
2270 assert(drv != NULL);
2272 /* If there are any driver level actions to take */
2273 if (drv->bdrv_reopen_commit) {
2274 drv->bdrv_reopen_commit(reopen_state);
2277 /* set BDS specific flags now */
2278 QDECREF(reopen_state->bs->explicit_options);
2280 reopen_state->bs->explicit_options = reopen_state->explicit_options;
2281 reopen_state->bs->open_flags = reopen_state->flags;
2282 reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
2284 bdrv_refresh_limits(reopen_state->bs, NULL);
2288 * Abort the reopen, and delete and free the staged changes in
2289 * reopen_state
2291 void bdrv_reopen_abort(BDRVReopenState *reopen_state)
2293 BlockDriver *drv;
2295 assert(reopen_state != NULL);
2296 drv = reopen_state->bs->drv;
2297 assert(drv != NULL);
2299 if (drv->bdrv_reopen_abort) {
2300 drv->bdrv_reopen_abort(reopen_state);
2303 QDECREF(reopen_state->explicit_options);
2307 static void bdrv_close(BlockDriverState *bs)
2309 BdrvAioNotifier *ban, *ban_next;
2311 assert(!bs->job);
2312 assert(!bs->refcnt);
2314 bdrv_drained_begin(bs); /* complete I/O */
2315 bdrv_flush(bs);
2316 bdrv_drain(bs); /* in case flush left pending I/O */
2318 bdrv_release_named_dirty_bitmaps(bs);
2319 assert(QLIST_EMPTY(&bs->dirty_bitmaps));
2321 if (bs->drv) {
2322 BdrvChild *child, *next;
2324 bs->drv->bdrv_close(bs);
2325 bs->drv = NULL;
2327 bdrv_set_backing_hd(bs, NULL);
2329 if (bs->file != NULL) {
2330 bdrv_unref_child(bs, bs->file);
2331 bs->file = NULL;
2334 QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
2335 /* TODO Remove bdrv_unref() from drivers' close function and use
2336 * bdrv_unref_child() here */
2337 if (child->bs->inherits_from == bs) {
2338 child->bs->inherits_from = NULL;
2340 bdrv_detach_child(child);
2343 g_free(bs->opaque);
2344 bs->opaque = NULL;
2345 bs->copy_on_read = 0;
2346 bs->backing_file[0] = '\0';
2347 bs->backing_format[0] = '\0';
2348 bs->total_sectors = 0;
2349 bs->encrypted = false;
2350 bs->valid_key = false;
2351 bs->sg = false;
2352 QDECREF(bs->options);
2353 QDECREF(bs->explicit_options);
2354 bs->options = NULL;
2355 QDECREF(bs->full_open_options);
2356 bs->full_open_options = NULL;
2359 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
2360 g_free(ban);
2362 QLIST_INIT(&bs->aio_notifiers);
2363 bdrv_drained_end(bs);
2366 void bdrv_close_all(void)
2368 block_job_cancel_sync_all();
2369 nbd_export_close_all();
2371 /* Drop references from requests still in flight, such as canceled block
2372 * jobs whose AIO context has not been polled yet */
2373 bdrv_drain_all();
2375 blk_remove_all_bs();
2376 blockdev_close_all_bdrv_states();
2378 assert(QTAILQ_EMPTY(&all_bdrv_states));
2381 static void change_parent_backing_link(BlockDriverState *from,
2382 BlockDriverState *to)
2384 BdrvChild *c, *next, *to_c;
2386 QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
2387 if (c->role == &child_backing) {
2388 /* @from is generally not allowed to be a backing file, except for
2389 * when @to is the overlay. In that case, @from may not be replaced
2390 * by @to as @to's backing node. */
2391 QLIST_FOREACH(to_c, &to->children, next) {
2392 if (to_c == c) {
2393 break;
2396 if (to_c) {
2397 continue;
2401 assert(c->role != &child_backing);
2402 bdrv_ref(to);
2403 bdrv_replace_child(c, to);
2404 bdrv_unref(from);
2409 * Add new bs contents at the top of an image chain while the chain is
2410 * live, while keeping required fields on the top layer.
2412 * This will modify the BlockDriverState fields, and swap contents
2413 * between bs_new and bs_top. Both bs_new and bs_top are modified.
2415 * bs_new must not be attached to a BlockBackend.
2417 * This function does not create any image files.
2419 * bdrv_append() takes ownership of a bs_new reference and unrefs it because
2420 * that's what the callers commonly need. bs_new will be referenced by the old
2421 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a
2422 * reference of its own, it must call bdrv_ref().
2424 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top)
2426 assert(!bdrv_requests_pending(bs_top));
2427 assert(!bdrv_requests_pending(bs_new));
2429 bdrv_ref(bs_top);
2431 change_parent_backing_link(bs_top, bs_new);
2432 bdrv_set_backing_hd(bs_new, bs_top);
2433 bdrv_unref(bs_top);
2435 /* bs_new is now referenced by its new parents, we don't need the
2436 * additional reference any more. */
2437 bdrv_unref(bs_new);
2440 void bdrv_replace_in_backing_chain(BlockDriverState *old, BlockDriverState *new)
2442 assert(!bdrv_requests_pending(old));
2443 assert(!bdrv_requests_pending(new));
2445 bdrv_ref(old);
2447 change_parent_backing_link(old, new);
2449 bdrv_unref(old);
2452 static void bdrv_delete(BlockDriverState *bs)
2454 assert(!bs->job);
2455 assert(bdrv_op_blocker_is_empty(bs));
2456 assert(!bs->refcnt);
2458 bdrv_close(bs);
2460 /* remove from list, if necessary */
2461 if (bs->node_name[0] != '\0') {
2462 QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list);
2464 QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list);
2466 g_free(bs);
2470 * Run consistency checks on an image
2472 * Returns 0 if the check could be completed (it doesn't mean that the image is
2473 * free of errors) or -errno when an internal error occurred. The results of the
2474 * check are stored in res.
2476 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix)
2478 if (bs->drv == NULL) {
2479 return -ENOMEDIUM;
2481 if (bs->drv->bdrv_check == NULL) {
2482 return -ENOTSUP;
2485 memset(res, 0, sizeof(*res));
2486 return bs->drv->bdrv_check(bs, res, fix);
2490 * Return values:
2491 * 0 - success
2492 * -EINVAL - backing format specified, but no file
2493 * -ENOSPC - can't update the backing file because no space is left in the
2494 * image file header
2495 * -ENOTSUP - format driver doesn't support changing the backing file
2497 int bdrv_change_backing_file(BlockDriverState *bs,
2498 const char *backing_file, const char *backing_fmt)
2500 BlockDriver *drv = bs->drv;
2501 int ret;
2503 /* Backing file format doesn't make sense without a backing file */
2504 if (backing_fmt && !backing_file) {
2505 return -EINVAL;
2508 if (drv->bdrv_change_backing_file != NULL) {
2509 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
2510 } else {
2511 ret = -ENOTSUP;
2514 if (ret == 0) {
2515 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
2516 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
2518 return ret;
2522 * Finds the image layer in the chain that has 'bs' as its backing file.
2524 * active is the current topmost image.
2526 * Returns NULL if bs is not found in active's image chain,
2527 * or if active == bs.
2529 * Returns the bottommost base image if bs == NULL.
2531 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
2532 BlockDriverState *bs)
2534 while (active && bs != backing_bs(active)) {
2535 active = backing_bs(active);
2538 return active;
2541 /* Given a BDS, searches for the base layer. */
2542 BlockDriverState *bdrv_find_base(BlockDriverState *bs)
2544 return bdrv_find_overlay(bs, NULL);
2548 * Drops images above 'base' up to and including 'top', and sets the image
2549 * above 'top' to have base as its backing file.
2551 * Requires that the overlay to 'top' is opened r/w, so that the backing file
2552 * information in 'bs' can be properly updated.
2554 * E.g., this will convert the following chain:
2555 * bottom <- base <- intermediate <- top <- active
2557 * to
2559 * bottom <- base <- active
2561 * It is allowed for bottom==base, in which case it converts:
2563 * base <- intermediate <- top <- active
2565 * to
2567 * base <- active
2569 * If backing_file_str is non-NULL, it will be used when modifying top's
2570 * overlay image metadata.
2572 * Error conditions:
2573 * if active == top, that is considered an error
2576 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
2577 BlockDriverState *base, const char *backing_file_str)
2579 BlockDriverState *new_top_bs = NULL;
2580 int ret = -EIO;
2582 if (!top->drv || !base->drv) {
2583 goto exit;
2586 new_top_bs = bdrv_find_overlay(active, top);
2588 if (new_top_bs == NULL) {
2589 /* we could not find the image above 'top', this is an error */
2590 goto exit;
2593 /* special case of new_top_bs->backing->bs already pointing to base - nothing
2594 * to do, no intermediate images */
2595 if (backing_bs(new_top_bs) == base) {
2596 ret = 0;
2597 goto exit;
2600 /* Make sure that base is in the backing chain of top */
2601 if (!bdrv_chain_contains(top, base)) {
2602 goto exit;
2605 /* success - we can delete the intermediate states, and link top->base */
2606 backing_file_str = backing_file_str ? backing_file_str : base->filename;
2607 ret = bdrv_change_backing_file(new_top_bs, backing_file_str,
2608 base->drv ? base->drv->format_name : "");
2609 if (ret) {
2610 goto exit;
2612 bdrv_set_backing_hd(new_top_bs, base);
2614 ret = 0;
2615 exit:
2616 return ret;
2620 * Truncate file to 'offset' bytes (needed only for file protocols)
2622 int bdrv_truncate(BlockDriverState *bs, int64_t offset)
2624 BlockDriver *drv = bs->drv;
2625 int ret;
2626 if (!drv)
2627 return -ENOMEDIUM;
2628 if (!drv->bdrv_truncate)
2629 return -ENOTSUP;
2630 if (bs->read_only)
2631 return -EACCES;
2633 ret = drv->bdrv_truncate(bs, offset);
2634 if (ret == 0) {
2635 ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
2636 bdrv_dirty_bitmap_truncate(bs);
2637 bdrv_parent_cb_resize(bs);
2638 ++bs->write_gen;
2640 return ret;
2644 * Length of a allocated file in bytes. Sparse files are counted by actual
2645 * allocated space. Return < 0 if error or unknown.
2647 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs)
2649 BlockDriver *drv = bs->drv;
2650 if (!drv) {
2651 return -ENOMEDIUM;
2653 if (drv->bdrv_get_allocated_file_size) {
2654 return drv->bdrv_get_allocated_file_size(bs);
2656 if (bs->file) {
2657 return bdrv_get_allocated_file_size(bs->file->bs);
2659 return -ENOTSUP;
2663 * Return number of sectors on success, -errno on error.
2665 int64_t bdrv_nb_sectors(BlockDriverState *bs)
2667 BlockDriver *drv = bs->drv;
2669 if (!drv)
2670 return -ENOMEDIUM;
2672 if (drv->has_variable_length) {
2673 int ret = refresh_total_sectors(bs, bs->total_sectors);
2674 if (ret < 0) {
2675 return ret;
2678 return bs->total_sectors;
2682 * Return length in bytes on success, -errno on error.
2683 * The length is always a multiple of BDRV_SECTOR_SIZE.
2685 int64_t bdrv_getlength(BlockDriverState *bs)
2687 int64_t ret = bdrv_nb_sectors(bs);
2689 ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret;
2690 return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE;
2693 /* return 0 as number of sectors if no device present or error */
2694 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
2696 int64_t nb_sectors = bdrv_nb_sectors(bs);
2698 *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors;
2701 bool bdrv_is_read_only(BlockDriverState *bs)
2703 return bs->read_only;
2706 bool bdrv_is_sg(BlockDriverState *bs)
2708 return bs->sg;
2711 bool bdrv_is_encrypted(BlockDriverState *bs)
2713 if (bs->backing && bs->backing->bs->encrypted) {
2714 return true;
2716 return bs->encrypted;
2719 bool bdrv_key_required(BlockDriverState *bs)
2721 BdrvChild *backing = bs->backing;
2723 if (backing && backing->bs->encrypted && !backing->bs->valid_key) {
2724 return true;
2726 return (bs->encrypted && !bs->valid_key);
2729 int bdrv_set_key(BlockDriverState *bs, const char *key)
2731 int ret;
2732 if (bs->backing && bs->backing->bs->encrypted) {
2733 ret = bdrv_set_key(bs->backing->bs, key);
2734 if (ret < 0)
2735 return ret;
2736 if (!bs->encrypted)
2737 return 0;
2739 if (!bs->encrypted) {
2740 return -EINVAL;
2741 } else if (!bs->drv || !bs->drv->bdrv_set_key) {
2742 return -ENOMEDIUM;
2744 ret = bs->drv->bdrv_set_key(bs, key);
2745 if (ret < 0) {
2746 bs->valid_key = false;
2747 } else if (!bs->valid_key) {
2748 /* call the change callback now, we skipped it on open */
2749 bs->valid_key = true;
2750 bdrv_parent_cb_change_media(bs, true);
2752 return ret;
2756 * Provide an encryption key for @bs.
2757 * If @key is non-null:
2758 * If @bs is not encrypted, fail.
2759 * Else if the key is invalid, fail.
2760 * Else set @bs's key to @key, replacing the existing key, if any.
2761 * If @key is null:
2762 * If @bs is encrypted and still lacks a key, fail.
2763 * Else do nothing.
2764 * On failure, store an error object through @errp if non-null.
2766 void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp)
2768 if (key) {
2769 if (!bdrv_is_encrypted(bs)) {
2770 error_setg(errp, "Node '%s' is not encrypted",
2771 bdrv_get_device_or_node_name(bs));
2772 } else if (bdrv_set_key(bs, key) < 0) {
2773 error_setg(errp, QERR_INVALID_PASSWORD);
2775 } else {
2776 if (bdrv_key_required(bs)) {
2777 error_set(errp, ERROR_CLASS_DEVICE_ENCRYPTED,
2778 "'%s' (%s) is encrypted",
2779 bdrv_get_device_or_node_name(bs),
2780 bdrv_get_encrypted_filename(bs));
2785 const char *bdrv_get_format_name(BlockDriverState *bs)
2787 return bs->drv ? bs->drv->format_name : NULL;
2790 static int qsort_strcmp(const void *a, const void *b)
2792 return strcmp(a, b);
2795 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
2796 void *opaque)
2798 BlockDriver *drv;
2799 int count = 0;
2800 int i;
2801 const char **formats = NULL;
2803 QLIST_FOREACH(drv, &bdrv_drivers, list) {
2804 if (drv->format_name) {
2805 bool found = false;
2806 int i = count;
2807 while (formats && i && !found) {
2808 found = !strcmp(formats[--i], drv->format_name);
2811 if (!found) {
2812 formats = g_renew(const char *, formats, count + 1);
2813 formats[count++] = drv->format_name;
2818 qsort(formats, count, sizeof(formats[0]), qsort_strcmp);
2820 for (i = 0; i < count; i++) {
2821 it(opaque, formats[i]);
2824 g_free(formats);
2827 /* This function is to find a node in the bs graph */
2828 BlockDriverState *bdrv_find_node(const char *node_name)
2830 BlockDriverState *bs;
2832 assert(node_name);
2834 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
2835 if (!strcmp(node_name, bs->node_name)) {
2836 return bs;
2839 return NULL;
2842 /* Put this QMP function here so it can access the static graph_bdrv_states. */
2843 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp)
2845 BlockDeviceInfoList *list, *entry;
2846 BlockDriverState *bs;
2848 list = NULL;
2849 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
2850 BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, errp);
2851 if (!info) {
2852 qapi_free_BlockDeviceInfoList(list);
2853 return NULL;
2855 entry = g_malloc0(sizeof(*entry));
2856 entry->value = info;
2857 entry->next = list;
2858 list = entry;
2861 return list;
2864 BlockDriverState *bdrv_lookup_bs(const char *device,
2865 const char *node_name,
2866 Error **errp)
2868 BlockBackend *blk;
2869 BlockDriverState *bs;
2871 if (device) {
2872 blk = blk_by_name(device);
2874 if (blk) {
2875 bs = blk_bs(blk);
2876 if (!bs) {
2877 error_setg(errp, "Device '%s' has no medium", device);
2880 return bs;
2884 if (node_name) {
2885 bs = bdrv_find_node(node_name);
2887 if (bs) {
2888 return bs;
2892 error_setg(errp, "Cannot find device=%s nor node_name=%s",
2893 device ? device : "",
2894 node_name ? node_name : "");
2895 return NULL;
2898 /* If 'base' is in the same chain as 'top', return true. Otherwise,
2899 * return false. If either argument is NULL, return false. */
2900 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base)
2902 while (top && top != base) {
2903 top = backing_bs(top);
2906 return top != NULL;
2909 BlockDriverState *bdrv_next_node(BlockDriverState *bs)
2911 if (!bs) {
2912 return QTAILQ_FIRST(&graph_bdrv_states);
2914 return QTAILQ_NEXT(bs, node_list);
2917 const char *bdrv_get_node_name(const BlockDriverState *bs)
2919 return bs->node_name;
2922 const char *bdrv_get_parent_name(const BlockDriverState *bs)
2924 BdrvChild *c;
2925 const char *name;
2927 /* If multiple parents have a name, just pick the first one. */
2928 QLIST_FOREACH(c, &bs->parents, next_parent) {
2929 if (c->role->get_name) {
2930 name = c->role->get_name(c);
2931 if (name && *name) {
2932 return name;
2937 return NULL;
2940 /* TODO check what callers really want: bs->node_name or blk_name() */
2941 const char *bdrv_get_device_name(const BlockDriverState *bs)
2943 return bdrv_get_parent_name(bs) ?: "";
2946 /* This can be used to identify nodes that might not have a device
2947 * name associated. Since node and device names live in the same
2948 * namespace, the result is unambiguous. The exception is if both are
2949 * absent, then this returns an empty (non-null) string. */
2950 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs)
2952 return bdrv_get_parent_name(bs) ?: bs->node_name;
2955 int bdrv_get_flags(BlockDriverState *bs)
2957 return bs->open_flags;
2960 int bdrv_has_zero_init_1(BlockDriverState *bs)
2962 return 1;
2965 int bdrv_has_zero_init(BlockDriverState *bs)
2967 assert(bs->drv);
2969 /* If BS is a copy on write image, it is initialized to
2970 the contents of the base image, which may not be zeroes. */
2971 if (bs->backing) {
2972 return 0;
2974 if (bs->drv->bdrv_has_zero_init) {
2975 return bs->drv->bdrv_has_zero_init(bs);
2978 /* safe default */
2979 return 0;
2982 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs)
2984 BlockDriverInfo bdi;
2986 if (bs->backing) {
2987 return false;
2990 if (bdrv_get_info(bs, &bdi) == 0) {
2991 return bdi.unallocated_blocks_are_zero;
2994 return false;
2997 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
2999 BlockDriverInfo bdi;
3001 if (!(bs->open_flags & BDRV_O_UNMAP)) {
3002 return false;
3005 if (bdrv_get_info(bs, &bdi) == 0) {
3006 return bdi.can_write_zeroes_with_unmap;
3009 return false;
3012 const char *bdrv_get_encrypted_filename(BlockDriverState *bs)
3014 if (bs->backing && bs->backing->bs->encrypted)
3015 return bs->backing_file;
3016 else if (bs->encrypted)
3017 return bs->filename;
3018 else
3019 return NULL;
3022 void bdrv_get_backing_filename(BlockDriverState *bs,
3023 char *filename, int filename_size)
3025 pstrcpy(filename, filename_size, bs->backing_file);
3028 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
3030 BlockDriver *drv = bs->drv;
3031 if (!drv)
3032 return -ENOMEDIUM;
3033 if (!drv->bdrv_get_info)
3034 return -ENOTSUP;
3035 memset(bdi, 0, sizeof(*bdi));
3036 return drv->bdrv_get_info(bs, bdi);
3039 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs)
3041 BlockDriver *drv = bs->drv;
3042 if (drv && drv->bdrv_get_specific_info) {
3043 return drv->bdrv_get_specific_info(bs);
3045 return NULL;
3048 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event)
3050 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
3051 return;
3054 bs->drv->bdrv_debug_event(bs, event);
3057 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
3058 const char *tag)
3060 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) {
3061 bs = bs->file ? bs->file->bs : NULL;
3064 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) {
3065 return bs->drv->bdrv_debug_breakpoint(bs, event, tag);
3068 return -ENOTSUP;
3071 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag)
3073 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) {
3074 bs = bs->file ? bs->file->bs : NULL;
3077 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) {
3078 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag);
3081 return -ENOTSUP;
3084 int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
3086 while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) {
3087 bs = bs->file ? bs->file->bs : NULL;
3090 if (bs && bs->drv && bs->drv->bdrv_debug_resume) {
3091 return bs->drv->bdrv_debug_resume(bs, tag);
3094 return -ENOTSUP;
3097 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag)
3099 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) {
3100 bs = bs->file ? bs->file->bs : NULL;
3103 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) {
3104 return bs->drv->bdrv_debug_is_suspended(bs, tag);
3107 return false;
3110 /* backing_file can either be relative, or absolute, or a protocol. If it is
3111 * relative, it must be relative to the chain. So, passing in bs->filename
3112 * from a BDS as backing_file should not be done, as that may be relative to
3113 * the CWD rather than the chain. */
3114 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
3115 const char *backing_file)
3117 char *filename_full = NULL;
3118 char *backing_file_full = NULL;
3119 char *filename_tmp = NULL;
3120 int is_protocol = 0;
3121 BlockDriverState *curr_bs = NULL;
3122 BlockDriverState *retval = NULL;
3124 if (!bs || !bs->drv || !backing_file) {
3125 return NULL;
3128 filename_full = g_malloc(PATH_MAX);
3129 backing_file_full = g_malloc(PATH_MAX);
3130 filename_tmp = g_malloc(PATH_MAX);
3132 is_protocol = path_has_protocol(backing_file);
3134 for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) {
3136 /* If either of the filename paths is actually a protocol, then
3137 * compare unmodified paths; otherwise make paths relative */
3138 if (is_protocol || path_has_protocol(curr_bs->backing_file)) {
3139 if (strcmp(backing_file, curr_bs->backing_file) == 0) {
3140 retval = curr_bs->backing->bs;
3141 break;
3143 } else {
3144 /* If not an absolute filename path, make it relative to the current
3145 * image's filename path */
3146 path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
3147 backing_file);
3149 /* We are going to compare absolute pathnames */
3150 if (!realpath(filename_tmp, filename_full)) {
3151 continue;
3154 /* We need to make sure the backing filename we are comparing against
3155 * is relative to the current image filename (or absolute) */
3156 path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
3157 curr_bs->backing_file);
3159 if (!realpath(filename_tmp, backing_file_full)) {
3160 continue;
3163 if (strcmp(backing_file_full, filename_full) == 0) {
3164 retval = curr_bs->backing->bs;
3165 break;
3170 g_free(filename_full);
3171 g_free(backing_file_full);
3172 g_free(filename_tmp);
3173 return retval;
3176 int bdrv_get_backing_file_depth(BlockDriverState *bs)
3178 if (!bs->drv) {
3179 return 0;
3182 if (!bs->backing) {
3183 return 0;
3186 return 1 + bdrv_get_backing_file_depth(bs->backing->bs);
3189 void bdrv_init(void)
3191 module_call_init(MODULE_INIT_BLOCK);
3194 void bdrv_init_with_whitelist(void)
3196 use_bdrv_whitelist = 1;
3197 bdrv_init();
3200 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
3202 BdrvChild *child;
3203 Error *local_err = NULL;
3204 int ret;
3206 if (!bs->drv) {
3207 return;
3210 if (!(bs->open_flags & BDRV_O_INACTIVE)) {
3211 return;
3213 bs->open_flags &= ~BDRV_O_INACTIVE;
3215 if (bs->drv->bdrv_invalidate_cache) {
3216 bs->drv->bdrv_invalidate_cache(bs, &local_err);
3217 if (local_err) {
3218 bs->open_flags |= BDRV_O_INACTIVE;
3219 error_propagate(errp, local_err);
3220 return;
3224 QLIST_FOREACH(child, &bs->children, next) {
3225 bdrv_invalidate_cache(child->bs, &local_err);
3226 if (local_err) {
3227 bs->open_flags |= BDRV_O_INACTIVE;
3228 error_propagate(errp, local_err);
3229 return;
3233 ret = refresh_total_sectors(bs, bs->total_sectors);
3234 if (ret < 0) {
3235 bs->open_flags |= BDRV_O_INACTIVE;
3236 error_setg_errno(errp, -ret, "Could not refresh total sector count");
3237 return;
3241 void bdrv_invalidate_cache_all(Error **errp)
3243 BlockDriverState *bs;
3244 Error *local_err = NULL;
3245 BdrvNextIterator it;
3247 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3248 AioContext *aio_context = bdrv_get_aio_context(bs);
3250 aio_context_acquire(aio_context);
3251 bdrv_invalidate_cache(bs, &local_err);
3252 aio_context_release(aio_context);
3253 if (local_err) {
3254 error_propagate(errp, local_err);
3255 return;
3260 static int bdrv_inactivate_recurse(BlockDriverState *bs,
3261 bool setting_flag)
3263 BdrvChild *child;
3264 int ret;
3266 if (!setting_flag && bs->drv->bdrv_inactivate) {
3267 ret = bs->drv->bdrv_inactivate(bs);
3268 if (ret < 0) {
3269 return ret;
3273 QLIST_FOREACH(child, &bs->children, next) {
3274 ret = bdrv_inactivate_recurse(child->bs, setting_flag);
3275 if (ret < 0) {
3276 return ret;
3280 if (setting_flag) {
3281 bs->open_flags |= BDRV_O_INACTIVE;
3283 return 0;
3286 int bdrv_inactivate_all(void)
3288 BlockDriverState *bs = NULL;
3289 BdrvNextIterator it;
3290 int ret = 0;
3291 int pass;
3293 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3294 aio_context_acquire(bdrv_get_aio_context(bs));
3297 /* We do two passes of inactivation. The first pass calls to drivers'
3298 * .bdrv_inactivate callbacks recursively so all cache is flushed to disk;
3299 * the second pass sets the BDRV_O_INACTIVE flag so that no further write
3300 * is allowed. */
3301 for (pass = 0; pass < 2; pass++) {
3302 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3303 ret = bdrv_inactivate_recurse(bs, pass);
3304 if (ret < 0) {
3305 goto out;
3310 out:
3311 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3312 aio_context_release(bdrv_get_aio_context(bs));
3315 return ret;
3318 /**************************************************************/
3319 /* removable device support */
3322 * Return TRUE if the media is present
3324 bool bdrv_is_inserted(BlockDriverState *bs)
3326 BlockDriver *drv = bs->drv;
3327 BdrvChild *child;
3329 if (!drv) {
3330 return false;
3332 if (drv->bdrv_is_inserted) {
3333 return drv->bdrv_is_inserted(bs);
3335 QLIST_FOREACH(child, &bs->children, next) {
3336 if (!bdrv_is_inserted(child->bs)) {
3337 return false;
3340 return true;
3344 * Return whether the media changed since the last call to this
3345 * function, or -ENOTSUP if we don't know. Most drivers don't know.
3347 int bdrv_media_changed(BlockDriverState *bs)
3349 BlockDriver *drv = bs->drv;
3351 if (drv && drv->bdrv_media_changed) {
3352 return drv->bdrv_media_changed(bs);
3354 return -ENOTSUP;
3358 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
3360 void bdrv_eject(BlockDriverState *bs, bool eject_flag)
3362 BlockDriver *drv = bs->drv;
3364 if (drv && drv->bdrv_eject) {
3365 drv->bdrv_eject(bs, eject_flag);
3370 * Lock or unlock the media (if it is locked, the user won't be able
3371 * to eject it manually).
3373 void bdrv_lock_medium(BlockDriverState *bs, bool locked)
3375 BlockDriver *drv = bs->drv;
3377 trace_bdrv_lock_medium(bs, locked);
3379 if (drv && drv->bdrv_lock_medium) {
3380 drv->bdrv_lock_medium(bs, locked);
3384 /* Get a reference to bs */
3385 void bdrv_ref(BlockDriverState *bs)
3387 bs->refcnt++;
3390 /* Release a previously grabbed reference to bs.
3391 * If after releasing, reference count is zero, the BlockDriverState is
3392 * deleted. */
3393 void bdrv_unref(BlockDriverState *bs)
3395 if (!bs) {
3396 return;
3398 assert(bs->refcnt > 0);
3399 if (--bs->refcnt == 0) {
3400 bdrv_delete(bs);
3404 struct BdrvOpBlocker {
3405 Error *reason;
3406 QLIST_ENTRY(BdrvOpBlocker) list;
3409 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp)
3411 BdrvOpBlocker *blocker;
3412 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
3413 if (!QLIST_EMPTY(&bs->op_blockers[op])) {
3414 blocker = QLIST_FIRST(&bs->op_blockers[op]);
3415 if (errp) {
3416 *errp = error_copy(blocker->reason);
3417 error_prepend(errp, "Node '%s' is busy: ",
3418 bdrv_get_device_or_node_name(bs));
3420 return true;
3422 return false;
3425 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason)
3427 BdrvOpBlocker *blocker;
3428 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
3430 blocker = g_new0(BdrvOpBlocker, 1);
3431 blocker->reason = reason;
3432 QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list);
3435 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason)
3437 BdrvOpBlocker *blocker, *next;
3438 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
3439 QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) {
3440 if (blocker->reason == reason) {
3441 QLIST_REMOVE(blocker, list);
3442 g_free(blocker);
3447 void bdrv_op_block_all(BlockDriverState *bs, Error *reason)
3449 int i;
3450 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
3451 bdrv_op_block(bs, i, reason);
3455 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason)
3457 int i;
3458 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
3459 bdrv_op_unblock(bs, i, reason);
3463 bool bdrv_op_blocker_is_empty(BlockDriverState *bs)
3465 int i;
3467 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
3468 if (!QLIST_EMPTY(&bs->op_blockers[i])) {
3469 return false;
3472 return true;
3475 void bdrv_img_create(const char *filename, const char *fmt,
3476 const char *base_filename, const char *base_fmt,
3477 char *options, uint64_t img_size, int flags,
3478 Error **errp, bool quiet)
3480 QemuOptsList *create_opts = NULL;
3481 QemuOpts *opts = NULL;
3482 const char *backing_fmt, *backing_file;
3483 int64_t size;
3484 BlockDriver *drv, *proto_drv;
3485 Error *local_err = NULL;
3486 int ret = 0;
3488 /* Find driver and parse its options */
3489 drv = bdrv_find_format(fmt);
3490 if (!drv) {
3491 error_setg(errp, "Unknown file format '%s'", fmt);
3492 return;
3495 proto_drv = bdrv_find_protocol(filename, true, errp);
3496 if (!proto_drv) {
3497 return;
3500 if (!drv->create_opts) {
3501 error_setg(errp, "Format driver '%s' does not support image creation",
3502 drv->format_name);
3503 return;
3506 if (!proto_drv->create_opts) {
3507 error_setg(errp, "Protocol driver '%s' does not support image creation",
3508 proto_drv->format_name);
3509 return;
3512 create_opts = qemu_opts_append(create_opts, drv->create_opts);
3513 create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
3515 /* Create parameter list with default values */
3516 opts = qemu_opts_create(create_opts, NULL, 0, &error_abort);
3517 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, img_size, &error_abort);
3519 /* Parse -o options */
3520 if (options) {
3521 qemu_opts_do_parse(opts, options, NULL, &local_err);
3522 if (local_err) {
3523 error_report_err(local_err);
3524 local_err = NULL;
3525 error_setg(errp, "Invalid options for file format '%s'", fmt);
3526 goto out;
3530 if (base_filename) {
3531 qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename, &local_err);
3532 if (local_err) {
3533 error_setg(errp, "Backing file not supported for file format '%s'",
3534 fmt);
3535 goto out;
3539 if (base_fmt) {
3540 qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt, &local_err);
3541 if (local_err) {
3542 error_setg(errp, "Backing file format not supported for file "
3543 "format '%s'", fmt);
3544 goto out;
3548 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
3549 if (backing_file) {
3550 if (!strcmp(filename, backing_file)) {
3551 error_setg(errp, "Error: Trying to create an image with the "
3552 "same filename as the backing file");
3553 goto out;
3557 backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
3559 // The size for the image must always be specified, with one exception:
3560 // If we are using a backing file, we can obtain the size from there
3561 size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
3562 if (size == -1) {
3563 if (backing_file) {
3564 BlockDriverState *bs;
3565 char *full_backing = g_new0(char, PATH_MAX);
3566 int64_t size;
3567 int back_flags;
3568 QDict *backing_options = NULL;
3570 bdrv_get_full_backing_filename_from_filename(filename, backing_file,
3571 full_backing, PATH_MAX,
3572 &local_err);
3573 if (local_err) {
3574 g_free(full_backing);
3575 goto out;
3578 /* backing files always opened read-only */
3579 back_flags = flags;
3580 back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
3582 if (backing_fmt) {
3583 backing_options = qdict_new();
3584 qdict_put(backing_options, "driver",
3585 qstring_from_str(backing_fmt));
3588 bs = bdrv_open(full_backing, NULL, backing_options, back_flags,
3589 &local_err);
3590 g_free(full_backing);
3591 if (!bs) {
3592 goto out;
3594 size = bdrv_getlength(bs);
3595 if (size < 0) {
3596 error_setg_errno(errp, -size, "Could not get size of '%s'",
3597 backing_file);
3598 bdrv_unref(bs);
3599 goto out;
3602 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort);
3604 bdrv_unref(bs);
3605 } else {
3606 error_setg(errp, "Image creation needs a size parameter");
3607 goto out;
3611 if (!quiet) {
3612 printf("Formatting '%s', fmt=%s ", filename, fmt);
3613 qemu_opts_print(opts, " ");
3614 puts("");
3617 ret = bdrv_create(drv, filename, opts, &local_err);
3619 if (ret == -EFBIG) {
3620 /* This is generally a better message than whatever the driver would
3621 * deliver (especially because of the cluster_size_hint), since that
3622 * is most probably not much different from "image too large". */
3623 const char *cluster_size_hint = "";
3624 if (qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 0)) {
3625 cluster_size_hint = " (try using a larger cluster size)";
3627 error_setg(errp, "The image size is too large for file format '%s'"
3628 "%s", fmt, cluster_size_hint);
3629 error_free(local_err);
3630 local_err = NULL;
3633 out:
3634 qemu_opts_del(opts);
3635 qemu_opts_free(create_opts);
3636 error_propagate(errp, local_err);
3639 AioContext *bdrv_get_aio_context(BlockDriverState *bs)
3641 return bs->aio_context;
3644 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban)
3646 QLIST_REMOVE(ban, list);
3647 g_free(ban);
3650 void bdrv_detach_aio_context(BlockDriverState *bs)
3652 BdrvAioNotifier *baf, *baf_tmp;
3653 BdrvChild *child;
3655 if (!bs->drv) {
3656 return;
3659 assert(!bs->walking_aio_notifiers);
3660 bs->walking_aio_notifiers = true;
3661 QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) {
3662 if (baf->deleted) {
3663 bdrv_do_remove_aio_context_notifier(baf);
3664 } else {
3665 baf->detach_aio_context(baf->opaque);
3668 /* Never mind iterating again to check for ->deleted. bdrv_close() will
3669 * remove remaining aio notifiers if we aren't called again.
3671 bs->walking_aio_notifiers = false;
3673 if (bs->drv->bdrv_detach_aio_context) {
3674 bs->drv->bdrv_detach_aio_context(bs);
3676 QLIST_FOREACH(child, &bs->children, next) {
3677 bdrv_detach_aio_context(child->bs);
3680 bs->aio_context = NULL;
3683 void bdrv_attach_aio_context(BlockDriverState *bs,
3684 AioContext *new_context)
3686 BdrvAioNotifier *ban, *ban_tmp;
3687 BdrvChild *child;
3689 if (!bs->drv) {
3690 return;
3693 bs->aio_context = new_context;
3695 QLIST_FOREACH(child, &bs->children, next) {
3696 bdrv_attach_aio_context(child->bs, new_context);
3698 if (bs->drv->bdrv_attach_aio_context) {
3699 bs->drv->bdrv_attach_aio_context(bs, new_context);
3702 assert(!bs->walking_aio_notifiers);
3703 bs->walking_aio_notifiers = true;
3704 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_tmp) {
3705 if (ban->deleted) {
3706 bdrv_do_remove_aio_context_notifier(ban);
3707 } else {
3708 ban->attached_aio_context(new_context, ban->opaque);
3711 bs->walking_aio_notifiers = false;
3714 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
3716 bdrv_drain(bs); /* ensure there are no in-flight requests */
3718 bdrv_detach_aio_context(bs);
3720 /* This function executes in the old AioContext so acquire the new one in
3721 * case it runs in a different thread.
3723 aio_context_acquire(new_context);
3724 bdrv_attach_aio_context(bs, new_context);
3725 aio_context_release(new_context);
3728 void bdrv_add_aio_context_notifier(BlockDriverState *bs,
3729 void (*attached_aio_context)(AioContext *new_context, void *opaque),
3730 void (*detach_aio_context)(void *opaque), void *opaque)
3732 BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1);
3733 *ban = (BdrvAioNotifier){
3734 .attached_aio_context = attached_aio_context,
3735 .detach_aio_context = detach_aio_context,
3736 .opaque = opaque
3739 QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list);
3742 void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
3743 void (*attached_aio_context)(AioContext *,
3744 void *),
3745 void (*detach_aio_context)(void *),
3746 void *opaque)
3748 BdrvAioNotifier *ban, *ban_next;
3750 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
3751 if (ban->attached_aio_context == attached_aio_context &&
3752 ban->detach_aio_context == detach_aio_context &&
3753 ban->opaque == opaque &&
3754 ban->deleted == false)
3756 if (bs->walking_aio_notifiers) {
3757 ban->deleted = true;
3758 } else {
3759 bdrv_do_remove_aio_context_notifier(ban);
3761 return;
3765 abort();
3768 int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts,
3769 BlockDriverAmendStatusCB *status_cb, void *cb_opaque)
3771 if (!bs->drv->bdrv_amend_options) {
3772 return -ENOTSUP;
3774 return bs->drv->bdrv_amend_options(bs, opts, status_cb, cb_opaque);
3777 /* This function will be called by the bdrv_recurse_is_first_non_filter method
3778 * of block filter and by bdrv_is_first_non_filter.
3779 * It is used to test if the given bs is the candidate or recurse more in the
3780 * node graph.
3782 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
3783 BlockDriverState *candidate)
3785 /* return false if basic checks fails */
3786 if (!bs || !bs->drv) {
3787 return false;
3790 /* the code reached a non block filter driver -> check if the bs is
3791 * the same as the candidate. It's the recursion termination condition.
3793 if (!bs->drv->is_filter) {
3794 return bs == candidate;
3796 /* Down this path the driver is a block filter driver */
3798 /* If the block filter recursion method is defined use it to recurse down
3799 * the node graph.
3801 if (bs->drv->bdrv_recurse_is_first_non_filter) {
3802 return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate);
3805 /* the driver is a block filter but don't allow to recurse -> return false
3807 return false;
3810 /* This function checks if the candidate is the first non filter bs down it's
3811 * bs chain. Since we don't have pointers to parents it explore all bs chains
3812 * from the top. Some filters can choose not to pass down the recursion.
3814 bool bdrv_is_first_non_filter(BlockDriverState *candidate)
3816 BlockDriverState *bs;
3817 BdrvNextIterator it;
3819 /* walk down the bs forest recursively */
3820 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3821 bool perm;
3823 /* try to recurse in this top level bs */
3824 perm = bdrv_recurse_is_first_non_filter(bs, candidate);
3826 /* candidate is the first non filter */
3827 if (perm) {
3828 return true;
3832 return false;
3835 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
3836 const char *node_name, Error **errp)
3838 BlockDriverState *to_replace_bs = bdrv_find_node(node_name);
3839 AioContext *aio_context;
3841 if (!to_replace_bs) {
3842 error_setg(errp, "Node name '%s' not found", node_name);
3843 return NULL;
3846 aio_context = bdrv_get_aio_context(to_replace_bs);
3847 aio_context_acquire(aio_context);
3849 if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) {
3850 to_replace_bs = NULL;
3851 goto out;
3854 /* We don't want arbitrary node of the BDS chain to be replaced only the top
3855 * most non filter in order to prevent data corruption.
3856 * Another benefit is that this tests exclude backing files which are
3857 * blocked by the backing blockers.
3859 if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) {
3860 error_setg(errp, "Only top most non filter can be replaced");
3861 to_replace_bs = NULL;
3862 goto out;
3865 out:
3866 aio_context_release(aio_context);
3867 return to_replace_bs;
3870 static bool append_open_options(QDict *d, BlockDriverState *bs)
3872 const QDictEntry *entry;
3873 QemuOptDesc *desc;
3874 BdrvChild *child;
3875 bool found_any = false;
3876 const char *p;
3878 for (entry = qdict_first(bs->options); entry;
3879 entry = qdict_next(bs->options, entry))
3881 /* Exclude options for children */
3882 QLIST_FOREACH(child, &bs->children, next) {
3883 if (strstart(qdict_entry_key(entry), child->name, &p)
3884 && (!*p || *p == '.'))
3886 break;
3889 if (child) {
3890 continue;
3893 /* And exclude all non-driver-specific options */
3894 for (desc = bdrv_runtime_opts.desc; desc->name; desc++) {
3895 if (!strcmp(qdict_entry_key(entry), desc->name)) {
3896 break;
3899 if (desc->name) {
3900 continue;
3903 qobject_incref(qdict_entry_value(entry));
3904 qdict_put_obj(d, qdict_entry_key(entry), qdict_entry_value(entry));
3905 found_any = true;
3908 return found_any;
3911 /* Updates the following BDS fields:
3912 * - exact_filename: A filename which may be used for opening a block device
3913 * which (mostly) equals the given BDS (even without any
3914 * other options; so reading and writing must return the same
3915 * results, but caching etc. may be different)
3916 * - full_open_options: Options which, when given when opening a block device
3917 * (without a filename), result in a BDS (mostly)
3918 * equalling the given one
3919 * - filename: If exact_filename is set, it is copied here. Otherwise,
3920 * full_open_options is converted to a JSON object, prefixed with
3921 * "json:" (for use through the JSON pseudo protocol) and put here.
3923 void bdrv_refresh_filename(BlockDriverState *bs)
3925 BlockDriver *drv = bs->drv;
3926 QDict *opts;
3928 if (!drv) {
3929 return;
3932 /* This BDS's file name will most probably depend on its file's name, so
3933 * refresh that first */
3934 if (bs->file) {
3935 bdrv_refresh_filename(bs->file->bs);
3938 if (drv->bdrv_refresh_filename) {
3939 /* Obsolete information is of no use here, so drop the old file name
3940 * information before refreshing it */
3941 bs->exact_filename[0] = '\0';
3942 if (bs->full_open_options) {
3943 QDECREF(bs->full_open_options);
3944 bs->full_open_options = NULL;
3947 opts = qdict_new();
3948 append_open_options(opts, bs);
3949 drv->bdrv_refresh_filename(bs, opts);
3950 QDECREF(opts);
3951 } else if (bs->file) {
3952 /* Try to reconstruct valid information from the underlying file */
3953 bool has_open_options;
3955 bs->exact_filename[0] = '\0';
3956 if (bs->full_open_options) {
3957 QDECREF(bs->full_open_options);
3958 bs->full_open_options = NULL;
3961 opts = qdict_new();
3962 has_open_options = append_open_options(opts, bs);
3964 /* If no specific options have been given for this BDS, the filename of
3965 * the underlying file should suffice for this one as well */
3966 if (bs->file->bs->exact_filename[0] && !has_open_options) {
3967 strcpy(bs->exact_filename, bs->file->bs->exact_filename);
3969 /* Reconstructing the full options QDict is simple for most format block
3970 * drivers, as long as the full options are known for the underlying
3971 * file BDS. The full options QDict of that file BDS should somehow
3972 * contain a representation of the filename, therefore the following
3973 * suffices without querying the (exact_)filename of this BDS. */
3974 if (bs->file->bs->full_open_options) {
3975 qdict_put_obj(opts, "driver",
3976 QOBJECT(qstring_from_str(drv->format_name)));
3977 QINCREF(bs->file->bs->full_open_options);
3978 qdict_put_obj(opts, "file",
3979 QOBJECT(bs->file->bs->full_open_options));
3981 bs->full_open_options = opts;
3982 } else {
3983 QDECREF(opts);
3985 } else if (!bs->full_open_options && qdict_size(bs->options)) {
3986 /* There is no underlying file BDS (at least referenced by BDS.file),
3987 * so the full options QDict should be equal to the options given
3988 * specifically for this block device when it was opened (plus the
3989 * driver specification).
3990 * Because those options don't change, there is no need to update
3991 * full_open_options when it's already set. */
3993 opts = qdict_new();
3994 append_open_options(opts, bs);
3995 qdict_put_obj(opts, "driver",
3996 QOBJECT(qstring_from_str(drv->format_name)));
3998 if (bs->exact_filename[0]) {
3999 /* This may not work for all block protocol drivers (some may
4000 * require this filename to be parsed), but we have to find some
4001 * default solution here, so just include it. If some block driver
4002 * does not support pure options without any filename at all or
4003 * needs some special format of the options QDict, it needs to
4004 * implement the driver-specific bdrv_refresh_filename() function.
4006 qdict_put_obj(opts, "filename",
4007 QOBJECT(qstring_from_str(bs->exact_filename)));
4010 bs->full_open_options = opts;
4013 if (bs->exact_filename[0]) {
4014 pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename);
4015 } else if (bs->full_open_options) {
4016 QString *json = qobject_to_json(QOBJECT(bs->full_open_options));
4017 snprintf(bs->filename, sizeof(bs->filename), "json:%s",
4018 qstring_get_str(json));
4019 QDECREF(json);
4024 * Hot add/remove a BDS's child. So the user can take a child offline when
4025 * it is broken and take a new child online
4027 void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs,
4028 Error **errp)
4031 if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) {
4032 error_setg(errp, "The node %s does not support adding a child",
4033 bdrv_get_device_or_node_name(parent_bs));
4034 return;
4037 if (!QLIST_EMPTY(&child_bs->parents)) {
4038 error_setg(errp, "The node %s already has a parent",
4039 child_bs->node_name);
4040 return;
4043 parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp);
4046 void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp)
4048 BdrvChild *tmp;
4050 if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) {
4051 error_setg(errp, "The node %s does not support removing a child",
4052 bdrv_get_device_or_node_name(parent_bs));
4053 return;
4056 QLIST_FOREACH(tmp, &parent_bs->children, next) {
4057 if (tmp == child) {
4058 break;
4062 if (!tmp) {
4063 error_setg(errp, "The node %s does not have a child named %s",
4064 bdrv_get_device_or_node_name(parent_bs),
4065 bdrv_get_device_or_node_name(child->bs));
4066 return;
4069 parent_bs->drv->bdrv_del_child(parent_bs, child, errp);