fsdev: spelling fix
[qemu.git] / block.c
blob736432f67edde405b6d765025f6f7c6d8ac1cc45
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 "qemu/error-report.h"
29 #include "qemu/module.h"
30 #include "qapi/qmp/qerror.h"
31 #include "qapi/qmp/qbool.h"
32 #include "qapi/qmp/qjson.h"
33 #include "sysemu/block-backend.h"
34 #include "sysemu/sysemu.h"
35 #include "qemu/notify.h"
36 #include "qemu/coroutine.h"
37 #include "block/qapi.h"
38 #include "qmp-commands.h"
39 #include "qemu/timer.h"
40 #include "qapi-event.h"
41 #include "qemu/cutils.h"
42 #include "qemu/id.h"
44 #ifdef CONFIG_BSD
45 #include <sys/ioctl.h>
46 #include <sys/queue.h>
47 #ifndef __DragonFly__
48 #include <sys/disk.h>
49 #endif
50 #endif
52 #ifdef _WIN32
53 #include <windows.h>
54 #endif
56 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
58 static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states =
59 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states);
61 static QTAILQ_HEAD(, BlockDriverState) all_bdrv_states =
62 QTAILQ_HEAD_INITIALIZER(all_bdrv_states);
64 static QLIST_HEAD(, BlockDriver) bdrv_drivers =
65 QLIST_HEAD_INITIALIZER(bdrv_drivers);
67 static BlockDriverState *bdrv_open_inherit(const char *filename,
68 const char *reference,
69 QDict *options, int flags,
70 BlockDriverState *parent,
71 const BdrvChildRole *child_role,
72 Error **errp);
74 /* If non-zero, use only whitelisted block drivers */
75 static int use_bdrv_whitelist;
77 #ifdef _WIN32
78 static int is_windows_drive_prefix(const char *filename)
80 return (((filename[0] >= 'a' && filename[0] <= 'z') ||
81 (filename[0] >= 'A' && filename[0] <= 'Z')) &&
82 filename[1] == ':');
85 int is_windows_drive(const char *filename)
87 if (is_windows_drive_prefix(filename) &&
88 filename[2] == '\0')
89 return 1;
90 if (strstart(filename, "\\\\.\\", NULL) ||
91 strstart(filename, "//./", NULL))
92 return 1;
93 return 0;
95 #endif
97 size_t bdrv_opt_mem_align(BlockDriverState *bs)
99 if (!bs || !bs->drv) {
100 /* page size or 4k (hdd sector size) should be on the safe side */
101 return MAX(4096, getpagesize());
104 return bs->bl.opt_mem_alignment;
107 size_t bdrv_min_mem_align(BlockDriverState *bs)
109 if (!bs || !bs->drv) {
110 /* page size or 4k (hdd sector size) should be on the safe side */
111 return MAX(4096, getpagesize());
114 return bs->bl.min_mem_alignment;
117 /* check if the path starts with "<protocol>:" */
118 int path_has_protocol(const char *path)
120 const char *p;
122 #ifdef _WIN32
123 if (is_windows_drive(path) ||
124 is_windows_drive_prefix(path)) {
125 return 0;
127 p = path + strcspn(path, ":/\\");
128 #else
129 p = path + strcspn(path, ":/");
130 #endif
132 return *p == ':';
135 int path_is_absolute(const char *path)
137 #ifdef _WIN32
138 /* specific case for names like: "\\.\d:" */
139 if (is_windows_drive(path) || is_windows_drive_prefix(path)) {
140 return 1;
142 return (*path == '/' || *path == '\\');
143 #else
144 return (*path == '/');
145 #endif
148 /* if filename is absolute, just copy it to dest. Otherwise, build a
149 path to it by considering it is relative to base_path. URL are
150 supported. */
151 void path_combine(char *dest, int dest_size,
152 const char *base_path,
153 const char *filename)
155 const char *p, *p1;
156 int len;
158 if (dest_size <= 0)
159 return;
160 if (path_is_absolute(filename)) {
161 pstrcpy(dest, dest_size, filename);
162 } else {
163 p = strchr(base_path, ':');
164 if (p)
165 p++;
166 else
167 p = base_path;
168 p1 = strrchr(base_path, '/');
169 #ifdef _WIN32
171 const char *p2;
172 p2 = strrchr(base_path, '\\');
173 if (!p1 || p2 > p1)
174 p1 = p2;
176 #endif
177 if (p1)
178 p1++;
179 else
180 p1 = base_path;
181 if (p1 > p)
182 p = p1;
183 len = p - base_path;
184 if (len > dest_size - 1)
185 len = dest_size - 1;
186 memcpy(dest, base_path, len);
187 dest[len] = '\0';
188 pstrcat(dest, dest_size, filename);
192 void bdrv_get_full_backing_filename_from_filename(const char *backed,
193 const char *backing,
194 char *dest, size_t sz,
195 Error **errp)
197 if (backing[0] == '\0' || path_has_protocol(backing) ||
198 path_is_absolute(backing))
200 pstrcpy(dest, sz, backing);
201 } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) {
202 error_setg(errp, "Cannot use relative backing file names for '%s'",
203 backed);
204 } else {
205 path_combine(dest, sz, backed, backing);
209 void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz,
210 Error **errp)
212 char *backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename;
214 bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file,
215 dest, sz, errp);
218 void bdrv_register(BlockDriver *bdrv)
220 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list);
223 BlockDriverState *bdrv_new(void)
225 BlockDriverState *bs;
226 int i;
228 bs = g_new0(BlockDriverState, 1);
229 QLIST_INIT(&bs->dirty_bitmaps);
230 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
231 QLIST_INIT(&bs->op_blockers[i]);
233 notifier_with_return_list_init(&bs->before_write_notifiers);
234 bs->refcnt = 1;
235 bs->aio_context = qemu_get_aio_context();
237 QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list);
239 return bs;
242 BlockDriver *bdrv_find_format(const char *format_name)
244 BlockDriver *drv1;
245 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
246 if (!strcmp(drv1->format_name, format_name)) {
247 return drv1;
250 return NULL;
253 static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
255 static const char *whitelist_rw[] = {
256 CONFIG_BDRV_RW_WHITELIST
258 static const char *whitelist_ro[] = {
259 CONFIG_BDRV_RO_WHITELIST
261 const char **p;
263 if (!whitelist_rw[0] && !whitelist_ro[0]) {
264 return 1; /* no whitelist, anything goes */
267 for (p = whitelist_rw; *p; p++) {
268 if (!strcmp(drv->format_name, *p)) {
269 return 1;
272 if (read_only) {
273 for (p = whitelist_ro; *p; p++) {
274 if (!strcmp(drv->format_name, *p)) {
275 return 1;
279 return 0;
282 bool bdrv_uses_whitelist(void)
284 return use_bdrv_whitelist;
287 typedef struct CreateCo {
288 BlockDriver *drv;
289 char *filename;
290 QemuOpts *opts;
291 int ret;
292 Error *err;
293 } CreateCo;
295 static void coroutine_fn bdrv_create_co_entry(void *opaque)
297 Error *local_err = NULL;
298 int ret;
300 CreateCo *cco = opaque;
301 assert(cco->drv);
303 ret = cco->drv->bdrv_create(cco->filename, cco->opts, &local_err);
304 if (local_err) {
305 error_propagate(&cco->err, local_err);
307 cco->ret = ret;
310 int bdrv_create(BlockDriver *drv, const char* filename,
311 QemuOpts *opts, Error **errp)
313 int ret;
315 Coroutine *co;
316 CreateCo cco = {
317 .drv = drv,
318 .filename = g_strdup(filename),
319 .opts = opts,
320 .ret = NOT_DONE,
321 .err = NULL,
324 if (!drv->bdrv_create) {
325 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name);
326 ret = -ENOTSUP;
327 goto out;
330 if (qemu_in_coroutine()) {
331 /* Fast-path if already in coroutine context */
332 bdrv_create_co_entry(&cco);
333 } else {
334 co = qemu_coroutine_create(bdrv_create_co_entry);
335 qemu_coroutine_enter(co, &cco);
336 while (cco.ret == NOT_DONE) {
337 aio_poll(qemu_get_aio_context(), true);
341 ret = cco.ret;
342 if (ret < 0) {
343 if (cco.err) {
344 error_propagate(errp, cco.err);
345 } else {
346 error_setg_errno(errp, -ret, "Could not create image");
350 out:
351 g_free(cco.filename);
352 return ret;
355 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
357 BlockDriver *drv;
358 Error *local_err = NULL;
359 int ret;
361 drv = bdrv_find_protocol(filename, true, errp);
362 if (drv == NULL) {
363 return -ENOENT;
366 ret = bdrv_create(drv, filename, opts, &local_err);
367 if (local_err) {
368 error_propagate(errp, local_err);
370 return ret;
374 * Try to get @bs's logical and physical block size.
375 * On success, store them in @bsz struct and return 0.
376 * On failure return -errno.
377 * @bs must not be empty.
379 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
381 BlockDriver *drv = bs->drv;
383 if (drv && drv->bdrv_probe_blocksizes) {
384 return drv->bdrv_probe_blocksizes(bs, bsz);
387 return -ENOTSUP;
391 * Try to get @bs's geometry (cyls, heads, sectors).
392 * On success, store them in @geo struct and return 0.
393 * On failure return -errno.
394 * @bs must not be empty.
396 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
398 BlockDriver *drv = bs->drv;
400 if (drv && drv->bdrv_probe_geometry) {
401 return drv->bdrv_probe_geometry(bs, geo);
404 return -ENOTSUP;
408 * Create a uniquely-named empty temporary file.
409 * Return 0 upon success, otherwise a negative errno value.
411 int get_tmp_filename(char *filename, int size)
413 #ifdef _WIN32
414 char temp_dir[MAX_PATH];
415 /* GetTempFileName requires that its output buffer (4th param)
416 have length MAX_PATH or greater. */
417 assert(size >= MAX_PATH);
418 return (GetTempPath(MAX_PATH, temp_dir)
419 && GetTempFileName(temp_dir, "qem", 0, filename)
420 ? 0 : -GetLastError());
421 #else
422 int fd;
423 const char *tmpdir;
424 tmpdir = getenv("TMPDIR");
425 if (!tmpdir) {
426 tmpdir = "/var/tmp";
428 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) {
429 return -EOVERFLOW;
431 fd = mkstemp(filename);
432 if (fd < 0) {
433 return -errno;
435 if (close(fd) != 0) {
436 unlink(filename);
437 return -errno;
439 return 0;
440 #endif
444 * Detect host devices. By convention, /dev/cdrom[N] is always
445 * recognized as a host CDROM.
447 static BlockDriver *find_hdev_driver(const char *filename)
449 int score_max = 0, score;
450 BlockDriver *drv = NULL, *d;
452 QLIST_FOREACH(d, &bdrv_drivers, list) {
453 if (d->bdrv_probe_device) {
454 score = d->bdrv_probe_device(filename);
455 if (score > score_max) {
456 score_max = score;
457 drv = d;
462 return drv;
465 BlockDriver *bdrv_find_protocol(const char *filename,
466 bool allow_protocol_prefix,
467 Error **errp)
469 BlockDriver *drv1;
470 char protocol[128];
471 int len;
472 const char *p;
474 /* TODO Drivers without bdrv_file_open must be specified explicitly */
477 * XXX(hch): we really should not let host device detection
478 * override an explicit protocol specification, but moving this
479 * later breaks access to device names with colons in them.
480 * Thanks to the brain-dead persistent naming schemes on udev-
481 * based Linux systems those actually are quite common.
483 drv1 = find_hdev_driver(filename);
484 if (drv1) {
485 return drv1;
488 if (!path_has_protocol(filename) || !allow_protocol_prefix) {
489 return &bdrv_file;
492 p = strchr(filename, ':');
493 assert(p != NULL);
494 len = p - filename;
495 if (len > sizeof(protocol) - 1)
496 len = sizeof(protocol) - 1;
497 memcpy(protocol, filename, len);
498 protocol[len] = '\0';
499 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
500 if (drv1->protocol_name &&
501 !strcmp(drv1->protocol_name, protocol)) {
502 return drv1;
506 error_setg(errp, "Unknown protocol '%s'", protocol);
507 return NULL;
511 * Guess image format by probing its contents.
512 * This is not a good idea when your image is raw (CVE-2008-2004), but
513 * we do it anyway for backward compatibility.
515 * @buf contains the image's first @buf_size bytes.
516 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
517 * but can be smaller if the image file is smaller)
518 * @filename is its filename.
520 * For all block drivers, call the bdrv_probe() method to get its
521 * probing score.
522 * Return the first block driver with the highest probing score.
524 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
525 const char *filename)
527 int score_max = 0, score;
528 BlockDriver *drv = NULL, *d;
530 QLIST_FOREACH(d, &bdrv_drivers, list) {
531 if (d->bdrv_probe) {
532 score = d->bdrv_probe(buf, buf_size, filename);
533 if (score > score_max) {
534 score_max = score;
535 drv = d;
540 return drv;
543 static int find_image_format(BlockDriverState *bs, const char *filename,
544 BlockDriver **pdrv, Error **errp)
546 BlockDriver *drv;
547 uint8_t buf[BLOCK_PROBE_BUF_SIZE];
548 int ret = 0;
550 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
551 if (bdrv_is_sg(bs) || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) {
552 *pdrv = &bdrv_raw;
553 return ret;
556 ret = bdrv_pread(bs, 0, buf, sizeof(buf));
557 if (ret < 0) {
558 error_setg_errno(errp, -ret, "Could not read image for determining its "
559 "format");
560 *pdrv = NULL;
561 return ret;
564 drv = bdrv_probe_all(buf, ret, filename);
565 if (!drv) {
566 error_setg(errp, "Could not determine image format: No compatible "
567 "driver found");
568 ret = -ENOENT;
570 *pdrv = drv;
571 return ret;
575 * Set the current 'total_sectors' value
576 * Return 0 on success, -errno on error.
578 static int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
580 BlockDriver *drv = bs->drv;
582 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
583 if (bdrv_is_sg(bs))
584 return 0;
586 /* query actual device if possible, otherwise just trust the hint */
587 if (drv->bdrv_getlength) {
588 int64_t length = drv->bdrv_getlength(bs);
589 if (length < 0) {
590 return length;
592 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE);
595 bs->total_sectors = hint;
596 return 0;
600 * Combines a QDict of new block driver @options with any missing options taken
601 * from @old_options, so that leaving out an option defaults to its old value.
603 static void bdrv_join_options(BlockDriverState *bs, QDict *options,
604 QDict *old_options)
606 if (bs->drv && bs->drv->bdrv_join_options) {
607 bs->drv->bdrv_join_options(options, old_options);
608 } else {
609 qdict_join(options, old_options, false);
614 * Set open flags for a given discard mode
616 * Return 0 on success, -1 if the discard mode was invalid.
618 int bdrv_parse_discard_flags(const char *mode, int *flags)
620 *flags &= ~BDRV_O_UNMAP;
622 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) {
623 /* do nothing */
624 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) {
625 *flags |= BDRV_O_UNMAP;
626 } else {
627 return -1;
630 return 0;
634 * Set open flags for a given cache mode
636 * Return 0 on success, -1 if the cache mode was invalid.
638 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough)
640 *flags &= ~BDRV_O_CACHE_MASK;
642 if (!strcmp(mode, "off") || !strcmp(mode, "none")) {
643 *writethrough = false;
644 *flags |= BDRV_O_NOCACHE;
645 } else if (!strcmp(mode, "directsync")) {
646 *writethrough = true;
647 *flags |= BDRV_O_NOCACHE;
648 } else if (!strcmp(mode, "writeback")) {
649 *writethrough = false;
650 } else if (!strcmp(mode, "unsafe")) {
651 *writethrough = false;
652 *flags |= BDRV_O_NO_FLUSH;
653 } else if (!strcmp(mode, "writethrough")) {
654 *writethrough = true;
655 } else {
656 return -1;
659 return 0;
662 static void bdrv_child_cb_drained_begin(BdrvChild *child)
664 BlockDriverState *bs = child->opaque;
665 bdrv_drained_begin(bs);
668 static void bdrv_child_cb_drained_end(BdrvChild *child)
670 BlockDriverState *bs = child->opaque;
671 bdrv_drained_end(bs);
675 * Returns the options and flags that a temporary snapshot should get, based on
676 * the originally requested flags (the originally requested image will have
677 * flags like a backing file)
679 static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
680 int parent_flags, QDict *parent_options)
682 *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY;
684 /* For temporary files, unconditional cache=unsafe is fine */
685 qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off");
686 qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
690 * Returns the options and flags that bs->file should get if a protocol driver
691 * is expected, based on the given options and flags for the parent BDS
693 static void bdrv_inherited_options(int *child_flags, QDict *child_options,
694 int parent_flags, QDict *parent_options)
696 int flags = parent_flags;
698 /* Enable protocol handling, disable format probing for bs->file */
699 flags |= BDRV_O_PROTOCOL;
701 /* If the cache mode isn't explicitly set, inherit direct and no-flush from
702 * the parent. */
703 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
704 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
706 /* Our block drivers take care to send flushes and respect unmap policy,
707 * so we can default to enable both on lower layers regardless of the
708 * corresponding parent options. */
709 flags |= BDRV_O_UNMAP;
711 /* Clear flags that only apply to the top layer */
712 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ |
713 BDRV_O_NO_IO);
715 *child_flags = flags;
718 const BdrvChildRole child_file = {
719 .inherit_options = bdrv_inherited_options,
720 .drained_begin = bdrv_child_cb_drained_begin,
721 .drained_end = bdrv_child_cb_drained_end,
725 * Returns the options and flags that bs->file should get if the use of formats
726 * (and not only protocols) is permitted for it, based on the given options and
727 * flags for the parent BDS
729 static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options,
730 int parent_flags, QDict *parent_options)
732 child_file.inherit_options(child_flags, child_options,
733 parent_flags, parent_options);
735 *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO);
738 const BdrvChildRole child_format = {
739 .inherit_options = bdrv_inherited_fmt_options,
740 .drained_begin = bdrv_child_cb_drained_begin,
741 .drained_end = bdrv_child_cb_drained_end,
745 * Returns the options and flags that bs->backing should get, based on the
746 * given options and flags for the parent BDS
748 static void bdrv_backing_options(int *child_flags, QDict *child_options,
749 int parent_flags, QDict *parent_options)
751 int flags = parent_flags;
753 /* The cache mode is inherited unmodified for backing files; except WCE,
754 * which is only applied on the top level (BlockBackend) */
755 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
756 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
758 /* backing files always opened read-only */
759 flags &= ~(BDRV_O_RDWR | BDRV_O_COPY_ON_READ);
761 /* snapshot=on is handled on the top layer */
762 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY);
764 *child_flags = flags;
767 static const BdrvChildRole child_backing = {
768 .inherit_options = bdrv_backing_options,
769 .drained_begin = bdrv_child_cb_drained_begin,
770 .drained_end = bdrv_child_cb_drained_end,
773 static int bdrv_open_flags(BlockDriverState *bs, int flags)
775 int open_flags = flags;
778 * Clear flags that are internal to the block layer before opening the
779 * image.
781 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL);
784 * Snapshots should be writable.
786 if (flags & BDRV_O_TEMPORARY) {
787 open_flags |= BDRV_O_RDWR;
790 return open_flags;
793 static void update_flags_from_options(int *flags, QemuOpts *opts)
795 *flags &= ~BDRV_O_CACHE_MASK;
797 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_NO_FLUSH));
798 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
799 *flags |= BDRV_O_NO_FLUSH;
802 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT));
803 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_DIRECT, false)) {
804 *flags |= BDRV_O_NOCACHE;
808 static void update_options_from_flags(QDict *options, int flags)
810 if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) {
811 qdict_put(options, BDRV_OPT_CACHE_DIRECT,
812 qbool_from_bool(flags & BDRV_O_NOCACHE));
814 if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) {
815 qdict_put(options, BDRV_OPT_CACHE_NO_FLUSH,
816 qbool_from_bool(flags & BDRV_O_NO_FLUSH));
820 static void bdrv_assign_node_name(BlockDriverState *bs,
821 const char *node_name,
822 Error **errp)
824 char *gen_node_name = NULL;
826 if (!node_name) {
827 node_name = gen_node_name = id_generate(ID_BLOCK);
828 } else if (!id_wellformed(node_name)) {
830 * Check for empty string or invalid characters, but not if it is
831 * generated (generated names use characters not available to the user)
833 error_setg(errp, "Invalid node name");
834 return;
837 /* takes care of avoiding namespaces collisions */
838 if (blk_by_name(node_name)) {
839 error_setg(errp, "node-name=%s is conflicting with a device id",
840 node_name);
841 goto out;
844 /* takes care of avoiding duplicates node names */
845 if (bdrv_find_node(node_name)) {
846 error_setg(errp, "Duplicate node name");
847 goto out;
850 /* copy node name into the bs and insert it into the graph list */
851 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
852 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
853 out:
854 g_free(gen_node_name);
857 static QemuOptsList bdrv_runtime_opts = {
858 .name = "bdrv_common",
859 .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head),
860 .desc = {
862 .name = "node-name",
863 .type = QEMU_OPT_STRING,
864 .help = "Node name of the block device node",
867 .name = "driver",
868 .type = QEMU_OPT_STRING,
869 .help = "Block driver to use for the node",
872 .name = BDRV_OPT_CACHE_DIRECT,
873 .type = QEMU_OPT_BOOL,
874 .help = "Bypass software writeback cache on the host",
877 .name = BDRV_OPT_CACHE_NO_FLUSH,
878 .type = QEMU_OPT_BOOL,
879 .help = "Ignore flush requests",
881 { /* end of list */ }
886 * Common part for opening disk images and files
888 * Removes all processed options from *options.
890 static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file,
891 QDict *options, Error **errp)
893 int ret, open_flags;
894 const char *filename;
895 const char *driver_name = NULL;
896 const char *node_name = NULL;
897 QemuOpts *opts;
898 BlockDriver *drv;
899 Error *local_err = NULL;
901 assert(bs->file == NULL);
902 assert(options != NULL && bs->options != options);
904 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
905 qemu_opts_absorb_qdict(opts, options, &local_err);
906 if (local_err) {
907 error_propagate(errp, local_err);
908 ret = -EINVAL;
909 goto fail_opts;
912 driver_name = qemu_opt_get(opts, "driver");
913 drv = bdrv_find_format(driver_name);
914 assert(drv != NULL);
916 if (file != NULL) {
917 filename = file->bs->filename;
918 } else {
919 filename = qdict_get_try_str(options, "filename");
922 if (drv->bdrv_needs_filename && !filename) {
923 error_setg(errp, "The '%s' block driver requires a file name",
924 drv->format_name);
925 ret = -EINVAL;
926 goto fail_opts;
929 trace_bdrv_open_common(bs, filename ?: "", bs->open_flags,
930 drv->format_name);
932 node_name = qemu_opt_get(opts, "node-name");
933 bdrv_assign_node_name(bs, node_name, &local_err);
934 if (local_err) {
935 error_propagate(errp, local_err);
936 ret = -EINVAL;
937 goto fail_opts;
940 bs->request_alignment = 512;
941 bs->zero_beyond_eof = true;
942 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
944 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
945 error_setg(errp,
946 !bs->read_only && bdrv_is_whitelisted(drv, true)
947 ? "Driver '%s' can only be used for read-only devices"
948 : "Driver '%s' is not whitelisted",
949 drv->format_name);
950 ret = -ENOTSUP;
951 goto fail_opts;
954 assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */
955 if (bs->open_flags & BDRV_O_COPY_ON_READ) {
956 if (!bs->read_only) {
957 bdrv_enable_copy_on_read(bs);
958 } else {
959 error_setg(errp, "Can't use copy-on-read on read-only device");
960 ret = -EINVAL;
961 goto fail_opts;
965 if (filename != NULL) {
966 pstrcpy(bs->filename, sizeof(bs->filename), filename);
967 } else {
968 bs->filename[0] = '\0';
970 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename);
972 bs->drv = drv;
973 bs->opaque = g_malloc0(drv->instance_size);
975 /* Apply cache mode options */
976 update_flags_from_options(&bs->open_flags, opts);
978 /* Open the image, either directly or using a protocol */
979 open_flags = bdrv_open_flags(bs, bs->open_flags);
980 if (drv->bdrv_file_open) {
981 assert(file == NULL);
982 assert(!drv->bdrv_needs_filename || filename != NULL);
983 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err);
984 } else {
985 if (file == NULL) {
986 error_setg(errp, "Can't use '%s' as a block driver for the "
987 "protocol level", drv->format_name);
988 ret = -EINVAL;
989 goto free_and_fail;
991 bs->file = file;
992 ret = drv->bdrv_open(bs, options, open_flags, &local_err);
995 if (ret < 0) {
996 if (local_err) {
997 error_propagate(errp, local_err);
998 } else if (bs->filename[0]) {
999 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename);
1000 } else {
1001 error_setg_errno(errp, -ret, "Could not open image");
1003 goto free_and_fail;
1006 ret = refresh_total_sectors(bs, bs->total_sectors);
1007 if (ret < 0) {
1008 error_setg_errno(errp, -ret, "Could not refresh total sector count");
1009 goto free_and_fail;
1012 bdrv_refresh_limits(bs, &local_err);
1013 if (local_err) {
1014 error_propagate(errp, local_err);
1015 ret = -EINVAL;
1016 goto free_and_fail;
1019 assert(bdrv_opt_mem_align(bs) != 0);
1020 assert(bdrv_min_mem_align(bs) != 0);
1021 assert((bs->request_alignment != 0) || bdrv_is_sg(bs));
1023 qemu_opts_del(opts);
1024 return 0;
1026 free_and_fail:
1027 bs->file = NULL;
1028 g_free(bs->opaque);
1029 bs->opaque = NULL;
1030 bs->drv = NULL;
1031 fail_opts:
1032 qemu_opts_del(opts);
1033 return ret;
1036 static QDict *parse_json_filename(const char *filename, Error **errp)
1038 QObject *options_obj;
1039 QDict *options;
1040 int ret;
1042 ret = strstart(filename, "json:", &filename);
1043 assert(ret);
1045 options_obj = qobject_from_json(filename);
1046 if (!options_obj) {
1047 error_setg(errp, "Could not parse the JSON options");
1048 return NULL;
1051 if (qobject_type(options_obj) != QTYPE_QDICT) {
1052 qobject_decref(options_obj);
1053 error_setg(errp, "Invalid JSON object given");
1054 return NULL;
1057 options = qobject_to_qdict(options_obj);
1058 qdict_flatten(options);
1060 return options;
1063 static void parse_json_protocol(QDict *options, const char **pfilename,
1064 Error **errp)
1066 QDict *json_options;
1067 Error *local_err = NULL;
1069 /* Parse json: pseudo-protocol */
1070 if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) {
1071 return;
1074 json_options = parse_json_filename(*pfilename, &local_err);
1075 if (local_err) {
1076 error_propagate(errp, local_err);
1077 return;
1080 /* Options given in the filename have lower priority than options
1081 * specified directly */
1082 qdict_join(options, json_options, false);
1083 QDECREF(json_options);
1084 *pfilename = NULL;
1088 * Fills in default options for opening images and converts the legacy
1089 * filename/flags pair to option QDict entries.
1090 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1091 * block driver has been specified explicitly.
1093 static int bdrv_fill_options(QDict **options, const char *filename,
1094 int *flags, Error **errp)
1096 const char *drvname;
1097 bool protocol = *flags & BDRV_O_PROTOCOL;
1098 bool parse_filename = false;
1099 BlockDriver *drv = NULL;
1100 Error *local_err = NULL;
1102 drvname = qdict_get_try_str(*options, "driver");
1103 if (drvname) {
1104 drv = bdrv_find_format(drvname);
1105 if (!drv) {
1106 error_setg(errp, "Unknown driver '%s'", drvname);
1107 return -ENOENT;
1109 /* If the user has explicitly specified the driver, this choice should
1110 * override the BDRV_O_PROTOCOL flag */
1111 protocol = drv->bdrv_file_open;
1114 if (protocol) {
1115 *flags |= BDRV_O_PROTOCOL;
1116 } else {
1117 *flags &= ~BDRV_O_PROTOCOL;
1120 /* Translate cache options from flags into options */
1121 update_options_from_flags(*options, *flags);
1123 /* Fetch the file name from the options QDict if necessary */
1124 if (protocol && filename) {
1125 if (!qdict_haskey(*options, "filename")) {
1126 qdict_put(*options, "filename", qstring_from_str(filename));
1127 parse_filename = true;
1128 } else {
1129 error_setg(errp, "Can't specify 'file' and 'filename' options at "
1130 "the same time");
1131 return -EINVAL;
1135 /* Find the right block driver */
1136 filename = qdict_get_try_str(*options, "filename");
1138 if (!drvname && protocol) {
1139 if (filename) {
1140 drv = bdrv_find_protocol(filename, parse_filename, errp);
1141 if (!drv) {
1142 return -EINVAL;
1145 drvname = drv->format_name;
1146 qdict_put(*options, "driver", qstring_from_str(drvname));
1147 } else {
1148 error_setg(errp, "Must specify either driver or file");
1149 return -EINVAL;
1153 assert(drv || !protocol);
1155 /* Driver-specific filename parsing */
1156 if (drv && drv->bdrv_parse_filename && parse_filename) {
1157 drv->bdrv_parse_filename(filename, *options, &local_err);
1158 if (local_err) {
1159 error_propagate(errp, local_err);
1160 return -EINVAL;
1163 if (!drv->bdrv_needs_filename) {
1164 qdict_del(*options, "filename");
1168 return 0;
1171 static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
1173 BlockDriverState *old_bs = child->bs;
1175 if (old_bs) {
1176 if (old_bs->quiesce_counter && child->role->drained_end) {
1177 child->role->drained_end(child);
1179 QLIST_REMOVE(child, next_parent);
1182 child->bs = new_bs;
1184 if (new_bs) {
1185 QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
1186 if (new_bs->quiesce_counter && child->role->drained_begin) {
1187 child->role->drained_begin(child);
1192 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
1193 const char *child_name,
1194 const BdrvChildRole *child_role,
1195 void *opaque)
1197 BdrvChild *child = g_new(BdrvChild, 1);
1198 *child = (BdrvChild) {
1199 .bs = NULL,
1200 .name = g_strdup(child_name),
1201 .role = child_role,
1202 .opaque = opaque,
1205 bdrv_replace_child(child, child_bs);
1207 return child;
1210 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
1211 BlockDriverState *child_bs,
1212 const char *child_name,
1213 const BdrvChildRole *child_role)
1215 BdrvChild *child = bdrv_root_attach_child(child_bs, child_name, child_role,
1216 parent_bs);
1217 QLIST_INSERT_HEAD(&parent_bs->children, child, next);
1218 return child;
1221 static void bdrv_detach_child(BdrvChild *child)
1223 if (child->next.le_prev) {
1224 QLIST_REMOVE(child, next);
1225 child->next.le_prev = NULL;
1228 bdrv_replace_child(child, NULL);
1230 g_free(child->name);
1231 g_free(child);
1234 void bdrv_root_unref_child(BdrvChild *child)
1236 BlockDriverState *child_bs;
1238 child_bs = child->bs;
1239 bdrv_detach_child(child);
1240 bdrv_unref(child_bs);
1243 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child)
1245 if (child == NULL) {
1246 return;
1249 if (child->bs->inherits_from == parent) {
1250 child->bs->inherits_from = NULL;
1253 bdrv_root_unref_child(child);
1257 static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load)
1259 BdrvChild *c;
1260 QLIST_FOREACH(c, &bs->parents, next_parent) {
1261 if (c->role->change_media) {
1262 c->role->change_media(c, load);
1267 static void bdrv_parent_cb_resize(BlockDriverState *bs)
1269 BdrvChild *c;
1270 QLIST_FOREACH(c, &bs->parents, next_parent) {
1271 if (c->role->resize) {
1272 c->role->resize(c);
1278 * Sets the backing file link of a BDS. A new reference is created; callers
1279 * which don't need their own reference any more must call bdrv_unref().
1281 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd)
1283 if (backing_hd) {
1284 bdrv_ref(backing_hd);
1287 if (bs->backing) {
1288 assert(bs->backing_blocker);
1289 bdrv_op_unblock_all(bs->backing->bs, bs->backing_blocker);
1290 bdrv_unref_child(bs, bs->backing);
1291 } else if (backing_hd) {
1292 error_setg(&bs->backing_blocker,
1293 "node is used as backing hd of '%s'",
1294 bdrv_get_device_or_node_name(bs));
1297 if (!backing_hd) {
1298 error_free(bs->backing_blocker);
1299 bs->backing_blocker = NULL;
1300 bs->backing = NULL;
1301 goto out;
1303 bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing);
1304 bs->open_flags &= ~BDRV_O_NO_BACKING;
1305 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_hd->filename);
1306 pstrcpy(bs->backing_format, sizeof(bs->backing_format),
1307 backing_hd->drv ? backing_hd->drv->format_name : "");
1309 bdrv_op_block_all(backing_hd, bs->backing_blocker);
1310 /* Otherwise we won't be able to commit due to check in bdrv_commit */
1311 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,
1312 bs->backing_blocker);
1313 out:
1314 bdrv_refresh_limits(bs, NULL);
1318 * Opens the backing file for a BlockDriverState if not yet open
1320 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
1321 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
1322 * itself, all options starting with "${bdref_key}." are considered part of the
1323 * BlockdevRef.
1325 * TODO Can this be unified with bdrv_open_image()?
1327 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
1328 const char *bdref_key, Error **errp)
1330 char *backing_filename = g_malloc0(PATH_MAX);
1331 char *bdref_key_dot;
1332 const char *reference = NULL;
1333 int ret = 0;
1334 BlockDriverState *backing_hd;
1335 QDict *options;
1336 QDict *tmp_parent_options = NULL;
1337 Error *local_err = NULL;
1339 if (bs->backing != NULL) {
1340 goto free_exit;
1343 /* NULL means an empty set of options */
1344 if (parent_options == NULL) {
1345 tmp_parent_options = qdict_new();
1346 parent_options = tmp_parent_options;
1349 bs->open_flags &= ~BDRV_O_NO_BACKING;
1351 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
1352 qdict_extract_subqdict(parent_options, &options, bdref_key_dot);
1353 g_free(bdref_key_dot);
1355 reference = qdict_get_try_str(parent_options, bdref_key);
1356 if (reference || qdict_haskey(options, "file.filename")) {
1357 backing_filename[0] = '\0';
1358 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
1359 QDECREF(options);
1360 goto free_exit;
1361 } else {
1362 bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX,
1363 &local_err);
1364 if (local_err) {
1365 ret = -EINVAL;
1366 error_propagate(errp, local_err);
1367 QDECREF(options);
1368 goto free_exit;
1372 if (!bs->drv || !bs->drv->supports_backing) {
1373 ret = -EINVAL;
1374 error_setg(errp, "Driver doesn't support backing files");
1375 QDECREF(options);
1376 goto free_exit;
1379 if (bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) {
1380 qdict_put(options, "driver", qstring_from_str(bs->backing_format));
1383 backing_hd = bdrv_open_inherit(*backing_filename ? backing_filename : NULL,
1384 reference, options, 0, bs, &child_backing,
1385 errp);
1386 if (!backing_hd) {
1387 bs->open_flags |= BDRV_O_NO_BACKING;
1388 error_prepend(errp, "Could not open backing file: ");
1389 ret = -EINVAL;
1390 goto free_exit;
1393 /* Hook up the backing file link; drop our reference, bs owns the
1394 * backing_hd reference now */
1395 bdrv_set_backing_hd(bs, backing_hd);
1396 bdrv_unref(backing_hd);
1398 qdict_del(parent_options, bdref_key);
1400 free_exit:
1401 g_free(backing_filename);
1402 QDECREF(tmp_parent_options);
1403 return ret;
1407 * Opens a disk image whose options are given as BlockdevRef in another block
1408 * device's options.
1410 * If allow_none is true, no image will be opened if filename is false and no
1411 * BlockdevRef is given. NULL will be returned, but errp remains unset.
1413 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
1414 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
1415 * itself, all options starting with "${bdref_key}." are considered part of the
1416 * BlockdevRef.
1418 * The BlockdevRef will be removed from the options QDict.
1420 BdrvChild *bdrv_open_child(const char *filename,
1421 QDict *options, const char *bdref_key,
1422 BlockDriverState* parent,
1423 const BdrvChildRole *child_role,
1424 bool allow_none, Error **errp)
1426 BdrvChild *c = NULL;
1427 BlockDriverState *bs;
1428 QDict *image_options;
1429 char *bdref_key_dot;
1430 const char *reference;
1432 assert(child_role != NULL);
1434 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
1435 qdict_extract_subqdict(options, &image_options, bdref_key_dot);
1436 g_free(bdref_key_dot);
1438 reference = qdict_get_try_str(options, bdref_key);
1439 if (!filename && !reference && !qdict_size(image_options)) {
1440 if (!allow_none) {
1441 error_setg(errp, "A block device must be specified for \"%s\"",
1442 bdref_key);
1444 QDECREF(image_options);
1445 goto done;
1448 bs = bdrv_open_inherit(filename, reference, image_options, 0,
1449 parent, child_role, errp);
1450 if (!bs) {
1451 goto done;
1454 c = bdrv_attach_child(parent, bs, bdref_key, child_role);
1456 done:
1457 qdict_del(options, bdref_key);
1458 return c;
1461 static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
1462 int flags,
1463 QDict *snapshot_options,
1464 Error **errp)
1466 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
1467 char *tmp_filename = g_malloc0(PATH_MAX + 1);
1468 int64_t total_size;
1469 QemuOpts *opts = NULL;
1470 BlockDriverState *bs_snapshot;
1471 int ret;
1473 /* if snapshot, we create a temporary backing file and open it
1474 instead of opening 'filename' directly */
1476 /* Get the required size from the image */
1477 total_size = bdrv_getlength(bs);
1478 if (total_size < 0) {
1479 error_setg_errno(errp, -total_size, "Could not get image size");
1480 goto out;
1483 /* Create the temporary image */
1484 ret = get_tmp_filename(tmp_filename, PATH_MAX + 1);
1485 if (ret < 0) {
1486 error_setg_errno(errp, -ret, "Could not get temporary filename");
1487 goto out;
1490 opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0,
1491 &error_abort);
1492 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort);
1493 ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp);
1494 qemu_opts_del(opts);
1495 if (ret < 0) {
1496 error_prepend(errp, "Could not create temporary overlay '%s': ",
1497 tmp_filename);
1498 goto out;
1501 /* Prepare options QDict for the temporary file */
1502 qdict_put(snapshot_options, "file.driver",
1503 qstring_from_str("file"));
1504 qdict_put(snapshot_options, "file.filename",
1505 qstring_from_str(tmp_filename));
1506 qdict_put(snapshot_options, "driver",
1507 qstring_from_str("qcow2"));
1509 bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp);
1510 snapshot_options = NULL;
1511 if (!bs_snapshot) {
1512 ret = -EINVAL;
1513 goto out;
1516 /* bdrv_append() consumes a strong reference to bs_snapshot (i.e. it will
1517 * call bdrv_unref() on it), so in order to be able to return one, we have
1518 * to increase bs_snapshot's refcount here */
1519 bdrv_ref(bs_snapshot);
1520 bdrv_append(bs_snapshot, bs);
1522 g_free(tmp_filename);
1523 return bs_snapshot;
1525 out:
1526 QDECREF(snapshot_options);
1527 g_free(tmp_filename);
1528 return NULL;
1532 * Opens a disk image (raw, qcow2, vmdk, ...)
1534 * options is a QDict of options to pass to the block drivers, or NULL for an
1535 * empty set of options. The reference to the QDict belongs to the block layer
1536 * after the call (even on failure), so if the caller intends to reuse the
1537 * dictionary, it needs to use QINCREF() before calling bdrv_open.
1539 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
1540 * If it is not NULL, the referenced BDS will be reused.
1542 * The reference parameter may be used to specify an existing block device which
1543 * should be opened. If specified, neither options nor a filename may be given,
1544 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
1546 static BlockDriverState *bdrv_open_inherit(const char *filename,
1547 const char *reference,
1548 QDict *options, int flags,
1549 BlockDriverState *parent,
1550 const BdrvChildRole *child_role,
1551 Error **errp)
1553 int ret;
1554 BdrvChild *file = NULL;
1555 BlockDriverState *bs;
1556 BlockDriver *drv = NULL;
1557 const char *drvname;
1558 const char *backing;
1559 Error *local_err = NULL;
1560 QDict *snapshot_options = NULL;
1561 int snapshot_flags = 0;
1563 assert(!child_role || !flags);
1564 assert(!child_role == !parent);
1566 if (reference) {
1567 bool options_non_empty = options ? qdict_size(options) : false;
1568 QDECREF(options);
1570 if (filename || options_non_empty) {
1571 error_setg(errp, "Cannot reference an existing block device with "
1572 "additional options or a new filename");
1573 return NULL;
1576 bs = bdrv_lookup_bs(reference, reference, errp);
1577 if (!bs) {
1578 return NULL;
1581 bdrv_ref(bs);
1582 return bs;
1585 bs = bdrv_new();
1587 /* NULL means an empty set of options */
1588 if (options == NULL) {
1589 options = qdict_new();
1592 /* json: syntax counts as explicit options, as if in the QDict */
1593 parse_json_protocol(options, &filename, &local_err);
1594 if (local_err) {
1595 goto fail;
1598 bs->explicit_options = qdict_clone_shallow(options);
1600 if (child_role) {
1601 bs->inherits_from = parent;
1602 child_role->inherit_options(&flags, options,
1603 parent->open_flags, parent->options);
1606 ret = bdrv_fill_options(&options, filename, &flags, &local_err);
1607 if (local_err) {
1608 goto fail;
1611 bs->open_flags = flags;
1612 bs->options = options;
1613 options = qdict_clone_shallow(options);
1615 /* Find the right image format driver */
1616 drvname = qdict_get_try_str(options, "driver");
1617 if (drvname) {
1618 drv = bdrv_find_format(drvname);
1619 if (!drv) {
1620 error_setg(errp, "Unknown driver: '%s'", drvname);
1621 goto fail;
1625 assert(drvname || !(flags & BDRV_O_PROTOCOL));
1627 backing = qdict_get_try_str(options, "backing");
1628 if (backing && *backing == '\0') {
1629 flags |= BDRV_O_NO_BACKING;
1630 qdict_del(options, "backing");
1633 /* Open image file without format layer */
1634 if ((flags & BDRV_O_PROTOCOL) == 0) {
1635 if (flags & BDRV_O_RDWR) {
1636 flags |= BDRV_O_ALLOW_RDWR;
1638 if (flags & BDRV_O_SNAPSHOT) {
1639 snapshot_options = qdict_new();
1640 bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options,
1641 flags, options);
1642 bdrv_backing_options(&flags, options, flags, options);
1645 bs->open_flags = flags;
1647 file = bdrv_open_child(filename, options, "file", bs,
1648 &child_file, true, &local_err);
1649 if (local_err) {
1650 goto fail;
1654 /* Image format probing */
1655 bs->probed = !drv;
1656 if (!drv && file) {
1657 ret = find_image_format(file->bs, filename, &drv, &local_err);
1658 if (ret < 0) {
1659 goto fail;
1662 * This option update would logically belong in bdrv_fill_options(),
1663 * but we first need to open bs->file for the probing to work, while
1664 * opening bs->file already requires the (mostly) final set of options
1665 * so that cache mode etc. can be inherited.
1667 * Adding the driver later is somewhat ugly, but it's not an option
1668 * that would ever be inherited, so it's correct. We just need to make
1669 * sure to update both bs->options (which has the full effective
1670 * options for bs) and options (which has file.* already removed).
1672 qdict_put(bs->options, "driver", qstring_from_str(drv->format_name));
1673 qdict_put(options, "driver", qstring_from_str(drv->format_name));
1674 } else if (!drv) {
1675 error_setg(errp, "Must specify either driver or file");
1676 goto fail;
1679 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
1680 assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open);
1681 /* file must be NULL if a protocol BDS is about to be created
1682 * (the inverse results in an error message from bdrv_open_common()) */
1683 assert(!(flags & BDRV_O_PROTOCOL) || !file);
1685 /* Open the image */
1686 ret = bdrv_open_common(bs, file, options, &local_err);
1687 if (ret < 0) {
1688 goto fail;
1691 if (file && (bs->file != file)) {
1692 bdrv_unref_child(bs, file);
1693 file = NULL;
1696 /* If there is a backing file, use it */
1697 if ((flags & BDRV_O_NO_BACKING) == 0) {
1698 ret = bdrv_open_backing_file(bs, options, "backing", &local_err);
1699 if (ret < 0) {
1700 goto close_and_fail;
1704 bdrv_refresh_filename(bs);
1706 /* Check if any unknown options were used */
1707 if (options && (qdict_size(options) != 0)) {
1708 const QDictEntry *entry = qdict_first(options);
1709 if (flags & BDRV_O_PROTOCOL) {
1710 error_setg(errp, "Block protocol '%s' doesn't support the option "
1711 "'%s'", drv->format_name, entry->key);
1712 } else {
1713 error_setg(errp,
1714 "Block format '%s' does not support the option '%s'",
1715 drv->format_name, entry->key);
1718 goto close_and_fail;
1721 if (!bdrv_key_required(bs)) {
1722 bdrv_parent_cb_change_media(bs, true);
1723 } else if (!runstate_check(RUN_STATE_PRELAUNCH)
1724 && !runstate_check(RUN_STATE_INMIGRATE)
1725 && !runstate_check(RUN_STATE_PAUSED)) { /* HACK */
1726 error_setg(errp,
1727 "Guest must be stopped for opening of encrypted image");
1728 goto close_and_fail;
1731 QDECREF(options);
1733 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
1734 * temporary snapshot afterwards. */
1735 if (snapshot_flags) {
1736 BlockDriverState *snapshot_bs;
1737 snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags,
1738 snapshot_options, &local_err);
1739 snapshot_options = NULL;
1740 if (local_err) {
1741 goto close_and_fail;
1743 /* We are not going to return bs but the overlay on top of it
1744 * (snapshot_bs); thus, we have to drop the strong reference to bs
1745 * (which we obtained by calling bdrv_new()). bs will not be deleted,
1746 * though, because the overlay still has a reference to it. */
1747 bdrv_unref(bs);
1748 bs = snapshot_bs;
1751 return bs;
1753 fail:
1754 if (file != NULL) {
1755 bdrv_unref_child(bs, file);
1757 QDECREF(snapshot_options);
1758 QDECREF(bs->explicit_options);
1759 QDECREF(bs->options);
1760 QDECREF(options);
1761 bs->options = NULL;
1762 bdrv_unref(bs);
1763 if (local_err) {
1764 error_propagate(errp, local_err);
1766 return NULL;
1768 close_and_fail:
1769 bdrv_unref(bs);
1770 QDECREF(snapshot_options);
1771 QDECREF(options);
1772 if (local_err) {
1773 error_propagate(errp, local_err);
1775 return NULL;
1778 BlockDriverState *bdrv_open(const char *filename, const char *reference,
1779 QDict *options, int flags, Error **errp)
1781 return bdrv_open_inherit(filename, reference, options, flags, NULL,
1782 NULL, errp);
1785 typedef struct BlockReopenQueueEntry {
1786 bool prepared;
1787 BDRVReopenState state;
1788 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry;
1789 } BlockReopenQueueEntry;
1792 * Adds a BlockDriverState to a simple queue for an atomic, transactional
1793 * reopen of multiple devices.
1795 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT
1796 * already performed, or alternatively may be NULL a new BlockReopenQueue will
1797 * be created and initialized. This newly created BlockReopenQueue should be
1798 * passed back in for subsequent calls that are intended to be of the same
1799 * atomic 'set'.
1801 * bs is the BlockDriverState to add to the reopen queue.
1803 * options contains the changed options for the associated bs
1804 * (the BlockReopenQueue takes ownership)
1806 * flags contains the open flags for the associated bs
1808 * returns a pointer to bs_queue, which is either the newly allocated
1809 * bs_queue, or the existing bs_queue being used.
1812 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
1813 BlockDriverState *bs,
1814 QDict *options,
1815 int flags,
1816 const BdrvChildRole *role,
1817 QDict *parent_options,
1818 int parent_flags)
1820 assert(bs != NULL);
1822 BlockReopenQueueEntry *bs_entry;
1823 BdrvChild *child;
1824 QDict *old_options, *explicit_options;
1826 if (bs_queue == NULL) {
1827 bs_queue = g_new0(BlockReopenQueue, 1);
1828 QSIMPLEQ_INIT(bs_queue);
1831 if (!options) {
1832 options = qdict_new();
1836 * Precedence of options:
1837 * 1. Explicitly passed in options (highest)
1838 * 2. Set in flags (only for top level)
1839 * 3. Retained from explicitly set options of bs
1840 * 4. Inherited from parent node
1841 * 5. Retained from effective options of bs
1844 if (!parent_options) {
1846 * Any setting represented by flags is always updated. If the
1847 * corresponding QDict option is set, it takes precedence. Otherwise
1848 * the flag is translated into a QDict option. The old setting of bs is
1849 * not considered.
1851 update_options_from_flags(options, flags);
1854 /* Old explicitly set values (don't overwrite by inherited value) */
1855 old_options = qdict_clone_shallow(bs->explicit_options);
1856 bdrv_join_options(bs, options, old_options);
1857 QDECREF(old_options);
1859 explicit_options = qdict_clone_shallow(options);
1861 /* Inherit from parent node */
1862 if (parent_options) {
1863 assert(!flags);
1864 role->inherit_options(&flags, options, parent_flags, parent_options);
1867 /* Old values are used for options that aren't set yet */
1868 old_options = qdict_clone_shallow(bs->options);
1869 bdrv_join_options(bs, options, old_options);
1870 QDECREF(old_options);
1872 /* bdrv_open() masks this flag out */
1873 flags &= ~BDRV_O_PROTOCOL;
1875 QLIST_FOREACH(child, &bs->children, next) {
1876 QDict *new_child_options;
1877 char *child_key_dot;
1879 /* reopen can only change the options of block devices that were
1880 * implicitly created and inherited options. For other (referenced)
1881 * block devices, a syntax like "backing.foo" results in an error. */
1882 if (child->bs->inherits_from != bs) {
1883 continue;
1886 child_key_dot = g_strdup_printf("%s.", child->name);
1887 qdict_extract_subqdict(options, &new_child_options, child_key_dot);
1888 g_free(child_key_dot);
1890 bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options, 0,
1891 child->role, options, flags);
1894 bs_entry = g_new0(BlockReopenQueueEntry, 1);
1895 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry);
1897 bs_entry->state.bs = bs;
1898 bs_entry->state.options = options;
1899 bs_entry->state.explicit_options = explicit_options;
1900 bs_entry->state.flags = flags;
1902 return bs_queue;
1905 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
1906 BlockDriverState *bs,
1907 QDict *options, int flags)
1909 return bdrv_reopen_queue_child(bs_queue, bs, options, flags,
1910 NULL, NULL, 0);
1914 * Reopen multiple BlockDriverStates atomically & transactionally.
1916 * The queue passed in (bs_queue) must have been built up previous
1917 * via bdrv_reopen_queue().
1919 * Reopens all BDS specified in the queue, with the appropriate
1920 * flags. All devices are prepared for reopen, and failure of any
1921 * device will cause all device changes to be abandonded, and intermediate
1922 * data cleaned up.
1924 * If all devices prepare successfully, then the changes are committed
1925 * to all devices.
1928 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
1930 int ret = -1;
1931 BlockReopenQueueEntry *bs_entry, *next;
1932 Error *local_err = NULL;
1934 assert(bs_queue != NULL);
1936 bdrv_drain_all();
1938 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
1939 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) {
1940 error_propagate(errp, local_err);
1941 goto cleanup;
1943 bs_entry->prepared = true;
1946 /* If we reach this point, we have success and just need to apply the
1947 * changes
1949 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
1950 bdrv_reopen_commit(&bs_entry->state);
1953 ret = 0;
1955 cleanup:
1956 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
1957 if (ret && bs_entry->prepared) {
1958 bdrv_reopen_abort(&bs_entry->state);
1959 } else if (ret) {
1960 QDECREF(bs_entry->state.explicit_options);
1962 QDECREF(bs_entry->state.options);
1963 g_free(bs_entry);
1965 g_free(bs_queue);
1966 return ret;
1970 /* Reopen a single BlockDriverState with the specified flags. */
1971 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp)
1973 int ret = -1;
1974 Error *local_err = NULL;
1975 BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags);
1977 ret = bdrv_reopen_multiple(queue, &local_err);
1978 if (local_err != NULL) {
1979 error_propagate(errp, local_err);
1981 return ret;
1986 * Prepares a BlockDriverState for reopen. All changes are staged in the
1987 * 'opaque' field of the BDRVReopenState, which is used and allocated by
1988 * the block driver layer .bdrv_reopen_prepare()
1990 * bs is the BlockDriverState to reopen
1991 * flags are the new open flags
1992 * queue is the reopen queue
1994 * Returns 0 on success, non-zero on error. On error errp will be set
1995 * as well.
1997 * On failure, bdrv_reopen_abort() will be called to clean up any data.
1998 * It is the responsibility of the caller to then call the abort() or
1999 * commit() for any other BDS that have been left in a prepare() state
2002 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
2003 Error **errp)
2005 int ret = -1;
2006 Error *local_err = NULL;
2007 BlockDriver *drv;
2008 QemuOpts *opts;
2009 const char *value;
2011 assert(reopen_state != NULL);
2012 assert(reopen_state->bs->drv != NULL);
2013 drv = reopen_state->bs->drv;
2015 /* Process generic block layer options */
2016 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
2017 qemu_opts_absorb_qdict(opts, reopen_state->options, &local_err);
2018 if (local_err) {
2019 error_propagate(errp, local_err);
2020 ret = -EINVAL;
2021 goto error;
2024 update_flags_from_options(&reopen_state->flags, opts);
2026 /* node-name and driver must be unchanged. Put them back into the QDict, so
2027 * that they are checked at the end of this function. */
2028 value = qemu_opt_get(opts, "node-name");
2029 if (value) {
2030 qdict_put(reopen_state->options, "node-name", qstring_from_str(value));
2033 value = qemu_opt_get(opts, "driver");
2034 if (value) {
2035 qdict_put(reopen_state->options, "driver", qstring_from_str(value));
2038 /* if we are to stay read-only, do not allow permission change
2039 * to r/w */
2040 if (!(reopen_state->bs->open_flags & BDRV_O_ALLOW_RDWR) &&
2041 reopen_state->flags & BDRV_O_RDWR) {
2042 error_setg(errp, "Node '%s' is read only",
2043 bdrv_get_device_or_node_name(reopen_state->bs));
2044 goto error;
2048 ret = bdrv_flush(reopen_state->bs);
2049 if (ret) {
2050 error_setg_errno(errp, -ret, "Error flushing drive");
2051 goto error;
2054 if (drv->bdrv_reopen_prepare) {
2055 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err);
2056 if (ret) {
2057 if (local_err != NULL) {
2058 error_propagate(errp, local_err);
2059 } else {
2060 error_setg(errp, "failed while preparing to reopen image '%s'",
2061 reopen_state->bs->filename);
2063 goto error;
2065 } else {
2066 /* It is currently mandatory to have a bdrv_reopen_prepare()
2067 * handler for each supported drv. */
2068 error_setg(errp, "Block format '%s' used by node '%s' "
2069 "does not support reopening files", drv->format_name,
2070 bdrv_get_device_or_node_name(reopen_state->bs));
2071 ret = -1;
2072 goto error;
2075 /* Options that are not handled are only okay if they are unchanged
2076 * compared to the old state. It is expected that some options are only
2077 * used for the initial open, but not reopen (e.g. filename) */
2078 if (qdict_size(reopen_state->options)) {
2079 const QDictEntry *entry = qdict_first(reopen_state->options);
2081 do {
2082 QString *new_obj = qobject_to_qstring(entry->value);
2083 const char *new = qstring_get_str(new_obj);
2084 const char *old = qdict_get_try_str(reopen_state->bs->options,
2085 entry->key);
2087 if (!old || strcmp(new, old)) {
2088 error_setg(errp, "Cannot change the option '%s'", entry->key);
2089 ret = -EINVAL;
2090 goto error;
2092 } while ((entry = qdict_next(reopen_state->options, entry)));
2095 ret = 0;
2097 error:
2098 qemu_opts_del(opts);
2099 return ret;
2103 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
2104 * makes them final by swapping the staging BlockDriverState contents into
2105 * the active BlockDriverState contents.
2107 void bdrv_reopen_commit(BDRVReopenState *reopen_state)
2109 BlockDriver *drv;
2111 assert(reopen_state != NULL);
2112 drv = reopen_state->bs->drv;
2113 assert(drv != NULL);
2115 /* If there are any driver level actions to take */
2116 if (drv->bdrv_reopen_commit) {
2117 drv->bdrv_reopen_commit(reopen_state);
2120 /* set BDS specific flags now */
2121 QDECREF(reopen_state->bs->explicit_options);
2123 reopen_state->bs->explicit_options = reopen_state->explicit_options;
2124 reopen_state->bs->open_flags = reopen_state->flags;
2125 reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
2127 bdrv_refresh_limits(reopen_state->bs, NULL);
2131 * Abort the reopen, and delete and free the staged changes in
2132 * reopen_state
2134 void bdrv_reopen_abort(BDRVReopenState *reopen_state)
2136 BlockDriver *drv;
2138 assert(reopen_state != NULL);
2139 drv = reopen_state->bs->drv;
2140 assert(drv != NULL);
2142 if (drv->bdrv_reopen_abort) {
2143 drv->bdrv_reopen_abort(reopen_state);
2146 QDECREF(reopen_state->explicit_options);
2150 static void bdrv_close(BlockDriverState *bs)
2152 BdrvAioNotifier *ban, *ban_next;
2154 assert(!bs->job);
2155 assert(!bs->refcnt);
2157 bdrv_drained_begin(bs); /* complete I/O */
2158 bdrv_flush(bs);
2159 bdrv_drain(bs); /* in case flush left pending I/O */
2161 bdrv_release_named_dirty_bitmaps(bs);
2162 assert(QLIST_EMPTY(&bs->dirty_bitmaps));
2164 if (bs->drv) {
2165 BdrvChild *child, *next;
2167 bs->drv->bdrv_close(bs);
2168 bs->drv = NULL;
2170 bdrv_set_backing_hd(bs, NULL);
2172 if (bs->file != NULL) {
2173 bdrv_unref_child(bs, bs->file);
2174 bs->file = NULL;
2177 QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
2178 /* TODO Remove bdrv_unref() from drivers' close function and use
2179 * bdrv_unref_child() here */
2180 if (child->bs->inherits_from == bs) {
2181 child->bs->inherits_from = NULL;
2183 bdrv_detach_child(child);
2186 g_free(bs->opaque);
2187 bs->opaque = NULL;
2188 bs->copy_on_read = 0;
2189 bs->backing_file[0] = '\0';
2190 bs->backing_format[0] = '\0';
2191 bs->total_sectors = 0;
2192 bs->encrypted = 0;
2193 bs->valid_key = 0;
2194 bs->sg = 0;
2195 bs->zero_beyond_eof = false;
2196 QDECREF(bs->options);
2197 QDECREF(bs->explicit_options);
2198 bs->options = NULL;
2199 QDECREF(bs->full_open_options);
2200 bs->full_open_options = NULL;
2203 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
2204 g_free(ban);
2206 QLIST_INIT(&bs->aio_notifiers);
2207 bdrv_drained_end(bs);
2210 void bdrv_close_all(void)
2212 block_job_cancel_sync_all();
2214 /* Drop references from requests still in flight, such as canceled block
2215 * jobs whose AIO context has not been polled yet */
2216 bdrv_drain_all();
2218 blk_remove_all_bs();
2219 blockdev_close_all_bdrv_states();
2221 assert(QTAILQ_EMPTY(&all_bdrv_states));
2224 static void change_parent_backing_link(BlockDriverState *from,
2225 BlockDriverState *to)
2227 BdrvChild *c, *next;
2229 QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
2230 assert(c->role != &child_backing);
2231 bdrv_ref(to);
2232 bdrv_replace_child(c, to);
2233 bdrv_unref(from);
2238 * Add new bs contents at the top of an image chain while the chain is
2239 * live, while keeping required fields on the top layer.
2241 * This will modify the BlockDriverState fields, and swap contents
2242 * between bs_new and bs_top. Both bs_new and bs_top are modified.
2244 * bs_new must not be attached to a BlockBackend.
2246 * This function does not create any image files.
2248 * bdrv_append() takes ownership of a bs_new reference and unrefs it because
2249 * that's what the callers commonly need. bs_new will be referenced by the old
2250 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a
2251 * reference of its own, it must call bdrv_ref().
2253 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top)
2255 assert(!bdrv_requests_pending(bs_top));
2256 assert(!bdrv_requests_pending(bs_new));
2258 bdrv_ref(bs_top);
2260 change_parent_backing_link(bs_top, bs_new);
2261 bdrv_set_backing_hd(bs_new, bs_top);
2262 bdrv_unref(bs_top);
2264 /* bs_new is now referenced by its new parents, we don't need the
2265 * additional reference any more. */
2266 bdrv_unref(bs_new);
2269 void bdrv_replace_in_backing_chain(BlockDriverState *old, BlockDriverState *new)
2271 assert(!bdrv_requests_pending(old));
2272 assert(!bdrv_requests_pending(new));
2274 bdrv_ref(old);
2276 change_parent_backing_link(old, new);
2278 /* Change backing files if a previously independent node is added to the
2279 * chain. For active commit, we replace top by its own (indirect) backing
2280 * file and don't do anything here so we don't build a loop. */
2281 if (new->backing == NULL && !bdrv_chain_contains(backing_bs(old), new)) {
2282 bdrv_set_backing_hd(new, backing_bs(old));
2283 bdrv_set_backing_hd(old, NULL);
2286 bdrv_unref(old);
2289 static void bdrv_delete(BlockDriverState *bs)
2291 assert(!bs->job);
2292 assert(bdrv_op_blocker_is_empty(bs));
2293 assert(!bs->refcnt);
2295 bdrv_close(bs);
2297 /* remove from list, if necessary */
2298 if (bs->node_name[0] != '\0') {
2299 QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list);
2301 QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list);
2303 g_free(bs);
2307 * Run consistency checks on an image
2309 * Returns 0 if the check could be completed (it doesn't mean that the image is
2310 * free of errors) or -errno when an internal error occurred. The results of the
2311 * check are stored in res.
2313 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix)
2315 if (bs->drv == NULL) {
2316 return -ENOMEDIUM;
2318 if (bs->drv->bdrv_check == NULL) {
2319 return -ENOTSUP;
2322 memset(res, 0, sizeof(*res));
2323 return bs->drv->bdrv_check(bs, res, fix);
2326 #define COMMIT_BUF_SECTORS 2048
2328 /* commit COW file into the raw image */
2329 int bdrv_commit(BlockDriverState *bs)
2331 BlockDriver *drv = bs->drv;
2332 int64_t sector, total_sectors, length, backing_length;
2333 int n, ro, open_flags;
2334 int ret = 0;
2335 uint8_t *buf = NULL;
2337 if (!drv)
2338 return -ENOMEDIUM;
2340 if (!bs->backing) {
2341 return -ENOTSUP;
2344 if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) ||
2345 bdrv_op_is_blocked(bs->backing->bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) {
2346 return -EBUSY;
2349 ro = bs->backing->bs->read_only;
2350 open_flags = bs->backing->bs->open_flags;
2352 if (ro) {
2353 if (bdrv_reopen(bs->backing->bs, open_flags | BDRV_O_RDWR, NULL)) {
2354 return -EACCES;
2358 length = bdrv_getlength(bs);
2359 if (length < 0) {
2360 ret = length;
2361 goto ro_cleanup;
2364 backing_length = bdrv_getlength(bs->backing->bs);
2365 if (backing_length < 0) {
2366 ret = backing_length;
2367 goto ro_cleanup;
2370 /* If our top snapshot is larger than the backing file image,
2371 * grow the backing file image if possible. If not possible,
2372 * we must return an error */
2373 if (length > backing_length) {
2374 ret = bdrv_truncate(bs->backing->bs, length);
2375 if (ret < 0) {
2376 goto ro_cleanup;
2380 total_sectors = length >> BDRV_SECTOR_BITS;
2382 /* qemu_try_blockalign() for bs will choose an alignment that works for
2383 * bs->backing->bs as well, so no need to compare the alignment manually. */
2384 buf = qemu_try_blockalign(bs, COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE);
2385 if (buf == NULL) {
2386 ret = -ENOMEM;
2387 goto ro_cleanup;
2390 for (sector = 0; sector < total_sectors; sector += n) {
2391 ret = bdrv_is_allocated(bs, sector, COMMIT_BUF_SECTORS, &n);
2392 if (ret < 0) {
2393 goto ro_cleanup;
2395 if (ret) {
2396 ret = bdrv_read(bs, sector, buf, n);
2397 if (ret < 0) {
2398 goto ro_cleanup;
2401 ret = bdrv_write(bs->backing->bs, sector, buf, n);
2402 if (ret < 0) {
2403 goto ro_cleanup;
2408 if (drv->bdrv_make_empty) {
2409 ret = drv->bdrv_make_empty(bs);
2410 if (ret < 0) {
2411 goto ro_cleanup;
2413 bdrv_flush(bs);
2417 * Make sure all data we wrote to the backing device is actually
2418 * stable on disk.
2420 if (bs->backing) {
2421 bdrv_flush(bs->backing->bs);
2424 ret = 0;
2425 ro_cleanup:
2426 qemu_vfree(buf);
2428 if (ro) {
2429 /* ignoring error return here */
2430 bdrv_reopen(bs->backing->bs, open_flags & ~BDRV_O_RDWR, NULL);
2433 return ret;
2437 * Return values:
2438 * 0 - success
2439 * -EINVAL - backing format specified, but no file
2440 * -ENOSPC - can't update the backing file because no space is left in the
2441 * image file header
2442 * -ENOTSUP - format driver doesn't support changing the backing file
2444 int bdrv_change_backing_file(BlockDriverState *bs,
2445 const char *backing_file, const char *backing_fmt)
2447 BlockDriver *drv = bs->drv;
2448 int ret;
2450 /* Backing file format doesn't make sense without a backing file */
2451 if (backing_fmt && !backing_file) {
2452 return -EINVAL;
2455 if (drv->bdrv_change_backing_file != NULL) {
2456 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
2457 } else {
2458 ret = -ENOTSUP;
2461 if (ret == 0) {
2462 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
2463 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
2465 return ret;
2469 * Finds the image layer in the chain that has 'bs' as its backing file.
2471 * active is the current topmost image.
2473 * Returns NULL if bs is not found in active's image chain,
2474 * or if active == bs.
2476 * Returns the bottommost base image if bs == NULL.
2478 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
2479 BlockDriverState *bs)
2481 while (active && bs != backing_bs(active)) {
2482 active = backing_bs(active);
2485 return active;
2488 /* Given a BDS, searches for the base layer. */
2489 BlockDriverState *bdrv_find_base(BlockDriverState *bs)
2491 return bdrv_find_overlay(bs, NULL);
2495 * Drops images above 'base' up to and including 'top', and sets the image
2496 * above 'top' to have base as its backing file.
2498 * Requires that the overlay to 'top' is opened r/w, so that the backing file
2499 * information in 'bs' can be properly updated.
2501 * E.g., this will convert the following chain:
2502 * bottom <- base <- intermediate <- top <- active
2504 * to
2506 * bottom <- base <- active
2508 * It is allowed for bottom==base, in which case it converts:
2510 * base <- intermediate <- top <- active
2512 * to
2514 * base <- active
2516 * If backing_file_str is non-NULL, it will be used when modifying top's
2517 * overlay image metadata.
2519 * Error conditions:
2520 * if active == top, that is considered an error
2523 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
2524 BlockDriverState *base, const char *backing_file_str)
2526 BlockDriverState *new_top_bs = NULL;
2527 int ret = -EIO;
2529 if (!top->drv || !base->drv) {
2530 goto exit;
2533 new_top_bs = bdrv_find_overlay(active, top);
2535 if (new_top_bs == NULL) {
2536 /* we could not find the image above 'top', this is an error */
2537 goto exit;
2540 /* special case of new_top_bs->backing->bs already pointing to base - nothing
2541 * to do, no intermediate images */
2542 if (backing_bs(new_top_bs) == base) {
2543 ret = 0;
2544 goto exit;
2547 /* Make sure that base is in the backing chain of top */
2548 if (!bdrv_chain_contains(top, base)) {
2549 goto exit;
2552 /* success - we can delete the intermediate states, and link top->base */
2553 backing_file_str = backing_file_str ? backing_file_str : base->filename;
2554 ret = bdrv_change_backing_file(new_top_bs, backing_file_str,
2555 base->drv ? base->drv->format_name : "");
2556 if (ret) {
2557 goto exit;
2559 bdrv_set_backing_hd(new_top_bs, base);
2561 ret = 0;
2562 exit:
2563 return ret;
2567 * Truncate file to 'offset' bytes (needed only for file protocols)
2569 int bdrv_truncate(BlockDriverState *bs, int64_t offset)
2571 BlockDriver *drv = bs->drv;
2572 int ret;
2573 if (!drv)
2574 return -ENOMEDIUM;
2575 if (!drv->bdrv_truncate)
2576 return -ENOTSUP;
2577 if (bs->read_only)
2578 return -EACCES;
2580 ret = drv->bdrv_truncate(bs, offset);
2581 if (ret == 0) {
2582 ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
2583 bdrv_dirty_bitmap_truncate(bs);
2584 bdrv_parent_cb_resize(bs);
2586 return ret;
2590 * Length of a allocated file in bytes. Sparse files are counted by actual
2591 * allocated space. Return < 0 if error or unknown.
2593 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs)
2595 BlockDriver *drv = bs->drv;
2596 if (!drv) {
2597 return -ENOMEDIUM;
2599 if (drv->bdrv_get_allocated_file_size) {
2600 return drv->bdrv_get_allocated_file_size(bs);
2602 if (bs->file) {
2603 return bdrv_get_allocated_file_size(bs->file->bs);
2605 return -ENOTSUP;
2609 * Return number of sectors on success, -errno on error.
2611 int64_t bdrv_nb_sectors(BlockDriverState *bs)
2613 BlockDriver *drv = bs->drv;
2615 if (!drv)
2616 return -ENOMEDIUM;
2618 if (drv->has_variable_length) {
2619 int ret = refresh_total_sectors(bs, bs->total_sectors);
2620 if (ret < 0) {
2621 return ret;
2624 return bs->total_sectors;
2628 * Return length in bytes on success, -errno on error.
2629 * The length is always a multiple of BDRV_SECTOR_SIZE.
2631 int64_t bdrv_getlength(BlockDriverState *bs)
2633 int64_t ret = bdrv_nb_sectors(bs);
2635 ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret;
2636 return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE;
2639 /* return 0 as number of sectors if no device present or error */
2640 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
2642 int64_t nb_sectors = bdrv_nb_sectors(bs);
2644 *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors;
2647 int bdrv_is_read_only(BlockDriverState *bs)
2649 return bs->read_only;
2652 int bdrv_is_sg(BlockDriverState *bs)
2654 return bs->sg;
2657 int bdrv_is_encrypted(BlockDriverState *bs)
2659 if (bs->backing && bs->backing->bs->encrypted) {
2660 return 1;
2662 return bs->encrypted;
2665 int bdrv_key_required(BlockDriverState *bs)
2667 BdrvChild *backing = bs->backing;
2669 if (backing && backing->bs->encrypted && !backing->bs->valid_key) {
2670 return 1;
2672 return (bs->encrypted && !bs->valid_key);
2675 int bdrv_set_key(BlockDriverState *bs, const char *key)
2677 int ret;
2678 if (bs->backing && bs->backing->bs->encrypted) {
2679 ret = bdrv_set_key(bs->backing->bs, key);
2680 if (ret < 0)
2681 return ret;
2682 if (!bs->encrypted)
2683 return 0;
2685 if (!bs->encrypted) {
2686 return -EINVAL;
2687 } else if (!bs->drv || !bs->drv->bdrv_set_key) {
2688 return -ENOMEDIUM;
2690 ret = bs->drv->bdrv_set_key(bs, key);
2691 if (ret < 0) {
2692 bs->valid_key = 0;
2693 } else if (!bs->valid_key) {
2694 /* call the change callback now, we skipped it on open */
2695 bs->valid_key = 1;
2696 bdrv_parent_cb_change_media(bs, true);
2698 return ret;
2702 * Provide an encryption key for @bs.
2703 * If @key is non-null:
2704 * If @bs is not encrypted, fail.
2705 * Else if the key is invalid, fail.
2706 * Else set @bs's key to @key, replacing the existing key, if any.
2707 * If @key is null:
2708 * If @bs is encrypted and still lacks a key, fail.
2709 * Else do nothing.
2710 * On failure, store an error object through @errp if non-null.
2712 void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp)
2714 if (key) {
2715 if (!bdrv_is_encrypted(bs)) {
2716 error_setg(errp, "Node '%s' is not encrypted",
2717 bdrv_get_device_or_node_name(bs));
2718 } else if (bdrv_set_key(bs, key) < 0) {
2719 error_setg(errp, QERR_INVALID_PASSWORD);
2721 } else {
2722 if (bdrv_key_required(bs)) {
2723 error_set(errp, ERROR_CLASS_DEVICE_ENCRYPTED,
2724 "'%s' (%s) is encrypted",
2725 bdrv_get_device_or_node_name(bs),
2726 bdrv_get_encrypted_filename(bs));
2731 const char *bdrv_get_format_name(BlockDriverState *bs)
2733 return bs->drv ? bs->drv->format_name : NULL;
2736 static int qsort_strcmp(const void *a, const void *b)
2738 return strcmp(a, b);
2741 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
2742 void *opaque)
2744 BlockDriver *drv;
2745 int count = 0;
2746 int i;
2747 const char **formats = NULL;
2749 QLIST_FOREACH(drv, &bdrv_drivers, list) {
2750 if (drv->format_name) {
2751 bool found = false;
2752 int i = count;
2753 while (formats && i && !found) {
2754 found = !strcmp(formats[--i], drv->format_name);
2757 if (!found) {
2758 formats = g_renew(const char *, formats, count + 1);
2759 formats[count++] = drv->format_name;
2764 qsort(formats, count, sizeof(formats[0]), qsort_strcmp);
2766 for (i = 0; i < count; i++) {
2767 it(opaque, formats[i]);
2770 g_free(formats);
2773 /* This function is to find a node in the bs graph */
2774 BlockDriverState *bdrv_find_node(const char *node_name)
2776 BlockDriverState *bs;
2778 assert(node_name);
2780 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
2781 if (!strcmp(node_name, bs->node_name)) {
2782 return bs;
2785 return NULL;
2788 /* Put this QMP function here so it can access the static graph_bdrv_states. */
2789 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp)
2791 BlockDeviceInfoList *list, *entry;
2792 BlockDriverState *bs;
2794 list = NULL;
2795 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
2796 BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, errp);
2797 if (!info) {
2798 qapi_free_BlockDeviceInfoList(list);
2799 return NULL;
2801 entry = g_malloc0(sizeof(*entry));
2802 entry->value = info;
2803 entry->next = list;
2804 list = entry;
2807 return list;
2810 BlockDriverState *bdrv_lookup_bs(const char *device,
2811 const char *node_name,
2812 Error **errp)
2814 BlockBackend *blk;
2815 BlockDriverState *bs;
2817 if (device) {
2818 blk = blk_by_name(device);
2820 if (blk) {
2821 bs = blk_bs(blk);
2822 if (!bs) {
2823 error_setg(errp, "Device '%s' has no medium", device);
2826 return bs;
2830 if (node_name) {
2831 bs = bdrv_find_node(node_name);
2833 if (bs) {
2834 return bs;
2838 error_setg(errp, "Cannot find device=%s nor node_name=%s",
2839 device ? device : "",
2840 node_name ? node_name : "");
2841 return NULL;
2844 /* If 'base' is in the same chain as 'top', return true. Otherwise,
2845 * return false. If either argument is NULL, return false. */
2846 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base)
2848 while (top && top != base) {
2849 top = backing_bs(top);
2852 return top != NULL;
2855 BlockDriverState *bdrv_next_node(BlockDriverState *bs)
2857 if (!bs) {
2858 return QTAILQ_FIRST(&graph_bdrv_states);
2860 return QTAILQ_NEXT(bs, node_list);
2863 const char *bdrv_get_node_name(const BlockDriverState *bs)
2865 return bs->node_name;
2868 const char *bdrv_get_parent_name(const BlockDriverState *bs)
2870 BdrvChild *c;
2871 const char *name;
2873 /* If multiple parents have a name, just pick the first one. */
2874 QLIST_FOREACH(c, &bs->parents, next_parent) {
2875 if (c->role->get_name) {
2876 name = c->role->get_name(c);
2877 if (name && *name) {
2878 return name;
2883 return NULL;
2886 /* TODO check what callers really want: bs->node_name or blk_name() */
2887 const char *bdrv_get_device_name(const BlockDriverState *bs)
2889 return bdrv_get_parent_name(bs) ?: "";
2892 /* This can be used to identify nodes that might not have a device
2893 * name associated. Since node and device names live in the same
2894 * namespace, the result is unambiguous. The exception is if both are
2895 * absent, then this returns an empty (non-null) string. */
2896 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs)
2898 return bdrv_get_parent_name(bs) ?: bs->node_name;
2901 int bdrv_get_flags(BlockDriverState *bs)
2903 return bs->open_flags;
2906 int bdrv_has_zero_init_1(BlockDriverState *bs)
2908 return 1;
2911 int bdrv_has_zero_init(BlockDriverState *bs)
2913 assert(bs->drv);
2915 /* If BS is a copy on write image, it is initialized to
2916 the contents of the base image, which may not be zeroes. */
2917 if (bs->backing) {
2918 return 0;
2920 if (bs->drv->bdrv_has_zero_init) {
2921 return bs->drv->bdrv_has_zero_init(bs);
2924 /* safe default */
2925 return 0;
2928 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs)
2930 BlockDriverInfo bdi;
2932 if (bs->backing) {
2933 return false;
2936 if (bdrv_get_info(bs, &bdi) == 0) {
2937 return bdi.unallocated_blocks_are_zero;
2940 return false;
2943 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
2945 BlockDriverInfo bdi;
2947 if (bs->backing || !(bs->open_flags & BDRV_O_UNMAP)) {
2948 return false;
2951 if (bdrv_get_info(bs, &bdi) == 0) {
2952 return bdi.can_write_zeroes_with_unmap;
2955 return false;
2958 const char *bdrv_get_encrypted_filename(BlockDriverState *bs)
2960 if (bs->backing && bs->backing->bs->encrypted)
2961 return bs->backing_file;
2962 else if (bs->encrypted)
2963 return bs->filename;
2964 else
2965 return NULL;
2968 void bdrv_get_backing_filename(BlockDriverState *bs,
2969 char *filename, int filename_size)
2971 pstrcpy(filename, filename_size, bs->backing_file);
2974 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
2976 BlockDriver *drv = bs->drv;
2977 if (!drv)
2978 return -ENOMEDIUM;
2979 if (!drv->bdrv_get_info)
2980 return -ENOTSUP;
2981 memset(bdi, 0, sizeof(*bdi));
2982 return drv->bdrv_get_info(bs, bdi);
2985 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs)
2987 BlockDriver *drv = bs->drv;
2988 if (drv && drv->bdrv_get_specific_info) {
2989 return drv->bdrv_get_specific_info(bs);
2991 return NULL;
2994 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event)
2996 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
2997 return;
3000 bs->drv->bdrv_debug_event(bs, event);
3003 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
3004 const char *tag)
3006 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) {
3007 bs = bs->file ? bs->file->bs : NULL;
3010 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) {
3011 return bs->drv->bdrv_debug_breakpoint(bs, event, tag);
3014 return -ENOTSUP;
3017 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag)
3019 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) {
3020 bs = bs->file ? bs->file->bs : NULL;
3023 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) {
3024 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag);
3027 return -ENOTSUP;
3030 int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
3032 while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) {
3033 bs = bs->file ? bs->file->bs : NULL;
3036 if (bs && bs->drv && bs->drv->bdrv_debug_resume) {
3037 return bs->drv->bdrv_debug_resume(bs, tag);
3040 return -ENOTSUP;
3043 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag)
3045 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) {
3046 bs = bs->file ? bs->file->bs : NULL;
3049 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) {
3050 return bs->drv->bdrv_debug_is_suspended(bs, tag);
3053 return false;
3056 int bdrv_is_snapshot(BlockDriverState *bs)
3058 return !!(bs->open_flags & BDRV_O_SNAPSHOT);
3061 /* backing_file can either be relative, or absolute, or a protocol. If it is
3062 * relative, it must be relative to the chain. So, passing in bs->filename
3063 * from a BDS as backing_file should not be done, as that may be relative to
3064 * the CWD rather than the chain. */
3065 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
3066 const char *backing_file)
3068 char *filename_full = NULL;
3069 char *backing_file_full = NULL;
3070 char *filename_tmp = NULL;
3071 int is_protocol = 0;
3072 BlockDriverState *curr_bs = NULL;
3073 BlockDriverState *retval = NULL;
3075 if (!bs || !bs->drv || !backing_file) {
3076 return NULL;
3079 filename_full = g_malloc(PATH_MAX);
3080 backing_file_full = g_malloc(PATH_MAX);
3081 filename_tmp = g_malloc(PATH_MAX);
3083 is_protocol = path_has_protocol(backing_file);
3085 for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) {
3087 /* If either of the filename paths is actually a protocol, then
3088 * compare unmodified paths; otherwise make paths relative */
3089 if (is_protocol || path_has_protocol(curr_bs->backing_file)) {
3090 if (strcmp(backing_file, curr_bs->backing_file) == 0) {
3091 retval = curr_bs->backing->bs;
3092 break;
3094 } else {
3095 /* If not an absolute filename path, make it relative to the current
3096 * image's filename path */
3097 path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
3098 backing_file);
3100 /* We are going to compare absolute pathnames */
3101 if (!realpath(filename_tmp, filename_full)) {
3102 continue;
3105 /* We need to make sure the backing filename we are comparing against
3106 * is relative to the current image filename (or absolute) */
3107 path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
3108 curr_bs->backing_file);
3110 if (!realpath(filename_tmp, backing_file_full)) {
3111 continue;
3114 if (strcmp(backing_file_full, filename_full) == 0) {
3115 retval = curr_bs->backing->bs;
3116 break;
3121 g_free(filename_full);
3122 g_free(backing_file_full);
3123 g_free(filename_tmp);
3124 return retval;
3127 int bdrv_get_backing_file_depth(BlockDriverState *bs)
3129 if (!bs->drv) {
3130 return 0;
3133 if (!bs->backing) {
3134 return 0;
3137 return 1 + bdrv_get_backing_file_depth(bs->backing->bs);
3140 void bdrv_init(void)
3142 module_call_init(MODULE_INIT_BLOCK);
3145 void bdrv_init_with_whitelist(void)
3147 use_bdrv_whitelist = 1;
3148 bdrv_init();
3151 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
3153 BdrvChild *child;
3154 Error *local_err = NULL;
3155 int ret;
3157 if (!bs->drv) {
3158 return;
3161 if (!(bs->open_flags & BDRV_O_INACTIVE)) {
3162 return;
3164 bs->open_flags &= ~BDRV_O_INACTIVE;
3166 if (bs->drv->bdrv_invalidate_cache) {
3167 bs->drv->bdrv_invalidate_cache(bs, &local_err);
3168 if (local_err) {
3169 bs->open_flags |= BDRV_O_INACTIVE;
3170 error_propagate(errp, local_err);
3171 return;
3175 QLIST_FOREACH(child, &bs->children, next) {
3176 bdrv_invalidate_cache(child->bs, &local_err);
3177 if (local_err) {
3178 bs->open_flags |= BDRV_O_INACTIVE;
3179 error_propagate(errp, local_err);
3180 return;
3184 ret = refresh_total_sectors(bs, bs->total_sectors);
3185 if (ret < 0) {
3186 bs->open_flags |= BDRV_O_INACTIVE;
3187 error_setg_errno(errp, -ret, "Could not refresh total sector count");
3188 return;
3192 void bdrv_invalidate_cache_all(Error **errp)
3194 BlockDriverState *bs;
3195 Error *local_err = NULL;
3196 BdrvNextIterator it;
3198 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3199 AioContext *aio_context = bdrv_get_aio_context(bs);
3201 aio_context_acquire(aio_context);
3202 bdrv_invalidate_cache(bs, &local_err);
3203 aio_context_release(aio_context);
3204 if (local_err) {
3205 error_propagate(errp, local_err);
3206 return;
3211 static int bdrv_inactivate_recurse(BlockDriverState *bs,
3212 bool setting_flag)
3214 BdrvChild *child;
3215 int ret;
3217 if (!setting_flag && bs->drv->bdrv_inactivate) {
3218 ret = bs->drv->bdrv_inactivate(bs);
3219 if (ret < 0) {
3220 return ret;
3224 QLIST_FOREACH(child, &bs->children, next) {
3225 ret = bdrv_inactivate_recurse(child->bs, setting_flag);
3226 if (ret < 0) {
3227 return ret;
3231 if (setting_flag) {
3232 bs->open_flags |= BDRV_O_INACTIVE;
3234 return 0;
3237 int bdrv_inactivate_all(void)
3239 BlockDriverState *bs = NULL;
3240 BdrvNextIterator it;
3241 int ret = 0;
3242 int pass;
3244 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3245 aio_context_acquire(bdrv_get_aio_context(bs));
3248 /* We do two passes of inactivation. The first pass calls to drivers'
3249 * .bdrv_inactivate callbacks recursively so all cache is flushed to disk;
3250 * the second pass sets the BDRV_O_INACTIVE flag so that no further write
3251 * is allowed. */
3252 for (pass = 0; pass < 2; pass++) {
3253 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3254 ret = bdrv_inactivate_recurse(bs, pass);
3255 if (ret < 0) {
3256 goto out;
3261 out:
3262 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3263 aio_context_release(bdrv_get_aio_context(bs));
3266 return ret;
3269 /**************************************************************/
3270 /* removable device support */
3273 * Return TRUE if the media is present
3275 bool bdrv_is_inserted(BlockDriverState *bs)
3277 BlockDriver *drv = bs->drv;
3278 BdrvChild *child;
3280 if (!drv) {
3281 return false;
3283 if (drv->bdrv_is_inserted) {
3284 return drv->bdrv_is_inserted(bs);
3286 QLIST_FOREACH(child, &bs->children, next) {
3287 if (!bdrv_is_inserted(child->bs)) {
3288 return false;
3291 return true;
3295 * Return whether the media changed since the last call to this
3296 * function, or -ENOTSUP if we don't know. Most drivers don't know.
3298 int bdrv_media_changed(BlockDriverState *bs)
3300 BlockDriver *drv = bs->drv;
3302 if (drv && drv->bdrv_media_changed) {
3303 return drv->bdrv_media_changed(bs);
3305 return -ENOTSUP;
3309 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
3311 void bdrv_eject(BlockDriverState *bs, bool eject_flag)
3313 BlockDriver *drv = bs->drv;
3314 const char *device_name;
3316 if (drv && drv->bdrv_eject) {
3317 drv->bdrv_eject(bs, eject_flag);
3320 device_name = bdrv_get_device_name(bs);
3321 if (device_name[0] != '\0') {
3322 qapi_event_send_device_tray_moved(device_name,
3323 eject_flag, &error_abort);
3328 * Lock or unlock the media (if it is locked, the user won't be able
3329 * to eject it manually).
3331 void bdrv_lock_medium(BlockDriverState *bs, bool locked)
3333 BlockDriver *drv = bs->drv;
3335 trace_bdrv_lock_medium(bs, locked);
3337 if (drv && drv->bdrv_lock_medium) {
3338 drv->bdrv_lock_medium(bs, locked);
3342 /* Get a reference to bs */
3343 void bdrv_ref(BlockDriverState *bs)
3345 bs->refcnt++;
3348 /* Release a previously grabbed reference to bs.
3349 * If after releasing, reference count is zero, the BlockDriverState is
3350 * deleted. */
3351 void bdrv_unref(BlockDriverState *bs)
3353 if (!bs) {
3354 return;
3356 assert(bs->refcnt > 0);
3357 if (--bs->refcnt == 0) {
3358 bdrv_delete(bs);
3362 struct BdrvOpBlocker {
3363 Error *reason;
3364 QLIST_ENTRY(BdrvOpBlocker) list;
3367 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp)
3369 BdrvOpBlocker *blocker;
3370 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
3371 if (!QLIST_EMPTY(&bs->op_blockers[op])) {
3372 blocker = QLIST_FIRST(&bs->op_blockers[op]);
3373 if (errp) {
3374 *errp = error_copy(blocker->reason);
3375 error_prepend(errp, "Node '%s' is busy: ",
3376 bdrv_get_device_or_node_name(bs));
3378 return true;
3380 return false;
3383 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason)
3385 BdrvOpBlocker *blocker;
3386 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
3388 blocker = g_new0(BdrvOpBlocker, 1);
3389 blocker->reason = reason;
3390 QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list);
3393 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason)
3395 BdrvOpBlocker *blocker, *next;
3396 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
3397 QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) {
3398 if (blocker->reason == reason) {
3399 QLIST_REMOVE(blocker, list);
3400 g_free(blocker);
3405 void bdrv_op_block_all(BlockDriverState *bs, Error *reason)
3407 int i;
3408 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
3409 bdrv_op_block(bs, i, reason);
3413 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason)
3415 int i;
3416 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
3417 bdrv_op_unblock(bs, i, reason);
3421 bool bdrv_op_blocker_is_empty(BlockDriverState *bs)
3423 int i;
3425 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
3426 if (!QLIST_EMPTY(&bs->op_blockers[i])) {
3427 return false;
3430 return true;
3433 void bdrv_img_create(const char *filename, const char *fmt,
3434 const char *base_filename, const char *base_fmt,
3435 char *options, uint64_t img_size, int flags,
3436 Error **errp, bool quiet)
3438 QemuOptsList *create_opts = NULL;
3439 QemuOpts *opts = NULL;
3440 const char *backing_fmt, *backing_file;
3441 int64_t size;
3442 BlockDriver *drv, *proto_drv;
3443 Error *local_err = NULL;
3444 int ret = 0;
3446 /* Find driver and parse its options */
3447 drv = bdrv_find_format(fmt);
3448 if (!drv) {
3449 error_setg(errp, "Unknown file format '%s'", fmt);
3450 return;
3453 proto_drv = bdrv_find_protocol(filename, true, errp);
3454 if (!proto_drv) {
3455 return;
3458 if (!drv->create_opts) {
3459 error_setg(errp, "Format driver '%s' does not support image creation",
3460 drv->format_name);
3461 return;
3464 if (!proto_drv->create_opts) {
3465 error_setg(errp, "Protocol driver '%s' does not support image creation",
3466 proto_drv->format_name);
3467 return;
3470 create_opts = qemu_opts_append(create_opts, drv->create_opts);
3471 create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
3473 /* Create parameter list with default values */
3474 opts = qemu_opts_create(create_opts, NULL, 0, &error_abort);
3475 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, img_size, &error_abort);
3477 /* Parse -o options */
3478 if (options) {
3479 qemu_opts_do_parse(opts, options, NULL, &local_err);
3480 if (local_err) {
3481 error_report_err(local_err);
3482 local_err = NULL;
3483 error_setg(errp, "Invalid options for file format '%s'", fmt);
3484 goto out;
3488 if (base_filename) {
3489 qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename, &local_err);
3490 if (local_err) {
3491 error_setg(errp, "Backing file not supported for file format '%s'",
3492 fmt);
3493 goto out;
3497 if (base_fmt) {
3498 qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt, &local_err);
3499 if (local_err) {
3500 error_setg(errp, "Backing file format not supported for file "
3501 "format '%s'", fmt);
3502 goto out;
3506 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
3507 if (backing_file) {
3508 if (!strcmp(filename, backing_file)) {
3509 error_setg(errp, "Error: Trying to create an image with the "
3510 "same filename as the backing file");
3511 goto out;
3515 backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
3517 // The size for the image must always be specified, with one exception:
3518 // If we are using a backing file, we can obtain the size from there
3519 size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
3520 if (size == -1) {
3521 if (backing_file) {
3522 BlockDriverState *bs;
3523 char *full_backing = g_new0(char, PATH_MAX);
3524 int64_t size;
3525 int back_flags;
3526 QDict *backing_options = NULL;
3528 bdrv_get_full_backing_filename_from_filename(filename, backing_file,
3529 full_backing, PATH_MAX,
3530 &local_err);
3531 if (local_err) {
3532 g_free(full_backing);
3533 goto out;
3536 /* backing files always opened read-only */
3537 back_flags = flags;
3538 back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
3540 if (backing_fmt) {
3541 backing_options = qdict_new();
3542 qdict_put(backing_options, "driver",
3543 qstring_from_str(backing_fmt));
3546 bs = bdrv_open(full_backing, NULL, backing_options, back_flags,
3547 &local_err);
3548 g_free(full_backing);
3549 if (!bs) {
3550 goto out;
3552 size = bdrv_getlength(bs);
3553 if (size < 0) {
3554 error_setg_errno(errp, -size, "Could not get size of '%s'",
3555 backing_file);
3556 bdrv_unref(bs);
3557 goto out;
3560 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort);
3562 bdrv_unref(bs);
3563 } else {
3564 error_setg(errp, "Image creation needs a size parameter");
3565 goto out;
3569 if (!quiet) {
3570 printf("Formatting '%s', fmt=%s ", filename, fmt);
3571 qemu_opts_print(opts, " ");
3572 puts("");
3575 ret = bdrv_create(drv, filename, opts, &local_err);
3577 if (ret == -EFBIG) {
3578 /* This is generally a better message than whatever the driver would
3579 * deliver (especially because of the cluster_size_hint), since that
3580 * is most probably not much different from "image too large". */
3581 const char *cluster_size_hint = "";
3582 if (qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 0)) {
3583 cluster_size_hint = " (try using a larger cluster size)";
3585 error_setg(errp, "The image size is too large for file format '%s'"
3586 "%s", fmt, cluster_size_hint);
3587 error_free(local_err);
3588 local_err = NULL;
3591 out:
3592 qemu_opts_del(opts);
3593 qemu_opts_free(create_opts);
3594 if (local_err) {
3595 error_propagate(errp, local_err);
3599 AioContext *bdrv_get_aio_context(BlockDriverState *bs)
3601 return bs->aio_context;
3604 void bdrv_detach_aio_context(BlockDriverState *bs)
3606 BdrvAioNotifier *baf;
3607 BdrvChild *child;
3609 if (!bs->drv) {
3610 return;
3613 QLIST_FOREACH(baf, &bs->aio_notifiers, list) {
3614 baf->detach_aio_context(baf->opaque);
3617 if (bs->drv->bdrv_detach_aio_context) {
3618 bs->drv->bdrv_detach_aio_context(bs);
3620 QLIST_FOREACH(child, &bs->children, next) {
3621 bdrv_detach_aio_context(child->bs);
3624 bs->aio_context = NULL;
3627 void bdrv_attach_aio_context(BlockDriverState *bs,
3628 AioContext *new_context)
3630 BdrvAioNotifier *ban;
3631 BdrvChild *child;
3633 if (!bs->drv) {
3634 return;
3637 bs->aio_context = new_context;
3639 QLIST_FOREACH(child, &bs->children, next) {
3640 bdrv_attach_aio_context(child->bs, new_context);
3642 if (bs->drv->bdrv_attach_aio_context) {
3643 bs->drv->bdrv_attach_aio_context(bs, new_context);
3646 QLIST_FOREACH(ban, &bs->aio_notifiers, list) {
3647 ban->attached_aio_context(new_context, ban->opaque);
3651 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
3653 bdrv_drain(bs); /* ensure there are no in-flight requests */
3655 bdrv_detach_aio_context(bs);
3657 /* This function executes in the old AioContext so acquire the new one in
3658 * case it runs in a different thread.
3660 aio_context_acquire(new_context);
3661 bdrv_attach_aio_context(bs, new_context);
3662 aio_context_release(new_context);
3665 void bdrv_add_aio_context_notifier(BlockDriverState *bs,
3666 void (*attached_aio_context)(AioContext *new_context, void *opaque),
3667 void (*detach_aio_context)(void *opaque), void *opaque)
3669 BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1);
3670 *ban = (BdrvAioNotifier){
3671 .attached_aio_context = attached_aio_context,
3672 .detach_aio_context = detach_aio_context,
3673 .opaque = opaque
3676 QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list);
3679 void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
3680 void (*attached_aio_context)(AioContext *,
3681 void *),
3682 void (*detach_aio_context)(void *),
3683 void *opaque)
3685 BdrvAioNotifier *ban, *ban_next;
3687 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
3688 if (ban->attached_aio_context == attached_aio_context &&
3689 ban->detach_aio_context == detach_aio_context &&
3690 ban->opaque == opaque)
3692 QLIST_REMOVE(ban, list);
3693 g_free(ban);
3695 return;
3699 abort();
3702 int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts,
3703 BlockDriverAmendStatusCB *status_cb, void *cb_opaque)
3705 if (!bs->drv->bdrv_amend_options) {
3706 return -ENOTSUP;
3708 return bs->drv->bdrv_amend_options(bs, opts, status_cb, cb_opaque);
3711 /* This function will be called by the bdrv_recurse_is_first_non_filter method
3712 * of block filter and by bdrv_is_first_non_filter.
3713 * It is used to test if the given bs is the candidate or recurse more in the
3714 * node graph.
3716 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
3717 BlockDriverState *candidate)
3719 /* return false if basic checks fails */
3720 if (!bs || !bs->drv) {
3721 return false;
3724 /* the code reached a non block filter driver -> check if the bs is
3725 * the same as the candidate. It's the recursion termination condition.
3727 if (!bs->drv->is_filter) {
3728 return bs == candidate;
3730 /* Down this path the driver is a block filter driver */
3732 /* If the block filter recursion method is defined use it to recurse down
3733 * the node graph.
3735 if (bs->drv->bdrv_recurse_is_first_non_filter) {
3736 return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate);
3739 /* the driver is a block filter but don't allow to recurse -> return false
3741 return false;
3744 /* This function checks if the candidate is the first non filter bs down it's
3745 * bs chain. Since we don't have pointers to parents it explore all bs chains
3746 * from the top. Some filters can choose not to pass down the recursion.
3748 bool bdrv_is_first_non_filter(BlockDriverState *candidate)
3750 BlockDriverState *bs;
3751 BdrvNextIterator it;
3753 /* walk down the bs forest recursively */
3754 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3755 bool perm;
3757 /* try to recurse in this top level bs */
3758 perm = bdrv_recurse_is_first_non_filter(bs, candidate);
3760 /* candidate is the first non filter */
3761 if (perm) {
3762 return true;
3766 return false;
3769 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
3770 const char *node_name, Error **errp)
3772 BlockDriverState *to_replace_bs = bdrv_find_node(node_name);
3773 AioContext *aio_context;
3775 if (!to_replace_bs) {
3776 error_setg(errp, "Node name '%s' not found", node_name);
3777 return NULL;
3780 aio_context = bdrv_get_aio_context(to_replace_bs);
3781 aio_context_acquire(aio_context);
3783 if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) {
3784 to_replace_bs = NULL;
3785 goto out;
3788 /* We don't want arbitrary node of the BDS chain to be replaced only the top
3789 * most non filter in order to prevent data corruption.
3790 * Another benefit is that this tests exclude backing files which are
3791 * blocked by the backing blockers.
3793 if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) {
3794 error_setg(errp, "Only top most non filter can be replaced");
3795 to_replace_bs = NULL;
3796 goto out;
3799 out:
3800 aio_context_release(aio_context);
3801 return to_replace_bs;
3804 static bool append_open_options(QDict *d, BlockDriverState *bs)
3806 const QDictEntry *entry;
3807 QemuOptDesc *desc;
3808 BdrvChild *child;
3809 bool found_any = false;
3810 const char *p;
3812 for (entry = qdict_first(bs->options); entry;
3813 entry = qdict_next(bs->options, entry))
3815 /* Exclude options for children */
3816 QLIST_FOREACH(child, &bs->children, next) {
3817 if (strstart(qdict_entry_key(entry), child->name, &p)
3818 && (!*p || *p == '.'))
3820 break;
3823 if (child) {
3824 continue;
3827 /* And exclude all non-driver-specific options */
3828 for (desc = bdrv_runtime_opts.desc; desc->name; desc++) {
3829 if (!strcmp(qdict_entry_key(entry), desc->name)) {
3830 break;
3833 if (desc->name) {
3834 continue;
3837 qobject_incref(qdict_entry_value(entry));
3838 qdict_put_obj(d, qdict_entry_key(entry), qdict_entry_value(entry));
3839 found_any = true;
3842 return found_any;
3845 /* Updates the following BDS fields:
3846 * - exact_filename: A filename which may be used for opening a block device
3847 * which (mostly) equals the given BDS (even without any
3848 * other options; so reading and writing must return the same
3849 * results, but caching etc. may be different)
3850 * - full_open_options: Options which, when given when opening a block device
3851 * (without a filename), result in a BDS (mostly)
3852 * equalling the given one
3853 * - filename: If exact_filename is set, it is copied here. Otherwise,
3854 * full_open_options is converted to a JSON object, prefixed with
3855 * "json:" (for use through the JSON pseudo protocol) and put here.
3857 void bdrv_refresh_filename(BlockDriverState *bs)
3859 BlockDriver *drv = bs->drv;
3860 QDict *opts;
3862 if (!drv) {
3863 return;
3866 /* This BDS's file name will most probably depend on its file's name, so
3867 * refresh that first */
3868 if (bs->file) {
3869 bdrv_refresh_filename(bs->file->bs);
3872 if (drv->bdrv_refresh_filename) {
3873 /* Obsolete information is of no use here, so drop the old file name
3874 * information before refreshing it */
3875 bs->exact_filename[0] = '\0';
3876 if (bs->full_open_options) {
3877 QDECREF(bs->full_open_options);
3878 bs->full_open_options = NULL;
3881 opts = qdict_new();
3882 append_open_options(opts, bs);
3883 drv->bdrv_refresh_filename(bs, opts);
3884 QDECREF(opts);
3885 } else if (bs->file) {
3886 /* Try to reconstruct valid information from the underlying file */
3887 bool has_open_options;
3889 bs->exact_filename[0] = '\0';
3890 if (bs->full_open_options) {
3891 QDECREF(bs->full_open_options);
3892 bs->full_open_options = NULL;
3895 opts = qdict_new();
3896 has_open_options = append_open_options(opts, bs);
3898 /* If no specific options have been given for this BDS, the filename of
3899 * the underlying file should suffice for this one as well */
3900 if (bs->file->bs->exact_filename[0] && !has_open_options) {
3901 strcpy(bs->exact_filename, bs->file->bs->exact_filename);
3903 /* Reconstructing the full options QDict is simple for most format block
3904 * drivers, as long as the full options are known for the underlying
3905 * file BDS. The full options QDict of that file BDS should somehow
3906 * contain a representation of the filename, therefore the following
3907 * suffices without querying the (exact_)filename of this BDS. */
3908 if (bs->file->bs->full_open_options) {
3909 qdict_put_obj(opts, "driver",
3910 QOBJECT(qstring_from_str(drv->format_name)));
3911 QINCREF(bs->file->bs->full_open_options);
3912 qdict_put_obj(opts, "file",
3913 QOBJECT(bs->file->bs->full_open_options));
3915 bs->full_open_options = opts;
3916 } else {
3917 QDECREF(opts);
3919 } else if (!bs->full_open_options && qdict_size(bs->options)) {
3920 /* There is no underlying file BDS (at least referenced by BDS.file),
3921 * so the full options QDict should be equal to the options given
3922 * specifically for this block device when it was opened (plus the
3923 * driver specification).
3924 * Because those options don't change, there is no need to update
3925 * full_open_options when it's already set. */
3927 opts = qdict_new();
3928 append_open_options(opts, bs);
3929 qdict_put_obj(opts, "driver",
3930 QOBJECT(qstring_from_str(drv->format_name)));
3932 if (bs->exact_filename[0]) {
3933 /* This may not work for all block protocol drivers (some may
3934 * require this filename to be parsed), but we have to find some
3935 * default solution here, so just include it. If some block driver
3936 * does not support pure options without any filename at all or
3937 * needs some special format of the options QDict, it needs to
3938 * implement the driver-specific bdrv_refresh_filename() function.
3940 qdict_put_obj(opts, "filename",
3941 QOBJECT(qstring_from_str(bs->exact_filename)));
3944 bs->full_open_options = opts;
3947 if (bs->exact_filename[0]) {
3948 pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename);
3949 } else if (bs->full_open_options) {
3950 QString *json = qobject_to_json(QOBJECT(bs->full_open_options));
3951 snprintf(bs->filename, sizeof(bs->filename), "json:%s",
3952 qstring_get_str(json));
3953 QDECREF(json);
3958 * Hot add/remove a BDS's child. So the user can take a child offline when
3959 * it is broken and take a new child online
3961 void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs,
3962 Error **errp)
3965 if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) {
3966 error_setg(errp, "The node %s does not support adding a child",
3967 bdrv_get_device_or_node_name(parent_bs));
3968 return;
3971 if (!QLIST_EMPTY(&child_bs->parents)) {
3972 error_setg(errp, "The node %s already has a parent",
3973 child_bs->node_name);
3974 return;
3977 parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp);
3980 void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp)
3982 BdrvChild *tmp;
3984 if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) {
3985 error_setg(errp, "The node %s does not support removing a child",
3986 bdrv_get_device_or_node_name(parent_bs));
3987 return;
3990 QLIST_FOREACH(tmp, &parent_bs->children, next) {
3991 if (tmp == child) {
3992 break;
3996 if (!tmp) {
3997 error_setg(errp, "The node %s does not have a child named %s",
3998 bdrv_get_device_or_node_name(parent_bs),
3999 bdrv_get_device_or_node_name(child->bs));
4000 return;
4003 parent_bs->drv->bdrv_del_child(parent_bs, child, errp);