commit: Add 'job-id' parameter to 'block-commit'
[qemu.git] / block.c
blob823ff1d7abdd73ec97a76fb7795be5b0a7fa53cf
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 error_propagate(&cco->err, local_err);
305 cco->ret = ret;
308 int bdrv_create(BlockDriver *drv, const char* filename,
309 QemuOpts *opts, Error **errp)
311 int ret;
313 Coroutine *co;
314 CreateCo cco = {
315 .drv = drv,
316 .filename = g_strdup(filename),
317 .opts = opts,
318 .ret = NOT_DONE,
319 .err = NULL,
322 if (!drv->bdrv_create) {
323 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name);
324 ret = -ENOTSUP;
325 goto out;
328 if (qemu_in_coroutine()) {
329 /* Fast-path if already in coroutine context */
330 bdrv_create_co_entry(&cco);
331 } else {
332 co = qemu_coroutine_create(bdrv_create_co_entry);
333 qemu_coroutine_enter(co, &cco);
334 while (cco.ret == NOT_DONE) {
335 aio_poll(qemu_get_aio_context(), true);
339 ret = cco.ret;
340 if (ret < 0) {
341 if (cco.err) {
342 error_propagate(errp, cco.err);
343 } else {
344 error_setg_errno(errp, -ret, "Could not create image");
348 out:
349 g_free(cco.filename);
350 return ret;
353 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
355 BlockDriver *drv;
356 Error *local_err = NULL;
357 int ret;
359 drv = bdrv_find_protocol(filename, true, errp);
360 if (drv == NULL) {
361 return -ENOENT;
364 ret = bdrv_create(drv, filename, opts, &local_err);
365 error_propagate(errp, local_err);
366 return ret;
370 * Try to get @bs's logical and physical block size.
371 * On success, store them in @bsz struct and return 0.
372 * On failure return -errno.
373 * @bs must not be empty.
375 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
377 BlockDriver *drv = bs->drv;
379 if (drv && drv->bdrv_probe_blocksizes) {
380 return drv->bdrv_probe_blocksizes(bs, bsz);
383 return -ENOTSUP;
387 * Try to get @bs's geometry (cyls, heads, sectors).
388 * On success, store them in @geo struct and return 0.
389 * On failure return -errno.
390 * @bs must not be empty.
392 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
394 BlockDriver *drv = bs->drv;
396 if (drv && drv->bdrv_probe_geometry) {
397 return drv->bdrv_probe_geometry(bs, geo);
400 return -ENOTSUP;
404 * Create a uniquely-named empty temporary file.
405 * Return 0 upon success, otherwise a negative errno value.
407 int get_tmp_filename(char *filename, int size)
409 #ifdef _WIN32
410 char temp_dir[MAX_PATH];
411 /* GetTempFileName requires that its output buffer (4th param)
412 have length MAX_PATH or greater. */
413 assert(size >= MAX_PATH);
414 return (GetTempPath(MAX_PATH, temp_dir)
415 && GetTempFileName(temp_dir, "qem", 0, filename)
416 ? 0 : -GetLastError());
417 #else
418 int fd;
419 const char *tmpdir;
420 tmpdir = getenv("TMPDIR");
421 if (!tmpdir) {
422 tmpdir = "/var/tmp";
424 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) {
425 return -EOVERFLOW;
427 fd = mkstemp(filename);
428 if (fd < 0) {
429 return -errno;
431 if (close(fd) != 0) {
432 unlink(filename);
433 return -errno;
435 return 0;
436 #endif
440 * Detect host devices. By convention, /dev/cdrom[N] is always
441 * recognized as a host CDROM.
443 static BlockDriver *find_hdev_driver(const char *filename)
445 int score_max = 0, score;
446 BlockDriver *drv = NULL, *d;
448 QLIST_FOREACH(d, &bdrv_drivers, list) {
449 if (d->bdrv_probe_device) {
450 score = d->bdrv_probe_device(filename);
451 if (score > score_max) {
452 score_max = score;
453 drv = d;
458 return drv;
461 BlockDriver *bdrv_find_protocol(const char *filename,
462 bool allow_protocol_prefix,
463 Error **errp)
465 BlockDriver *drv1;
466 char protocol[128];
467 int len;
468 const char *p;
470 /* TODO Drivers without bdrv_file_open must be specified explicitly */
473 * XXX(hch): we really should not let host device detection
474 * override an explicit protocol specification, but moving this
475 * later breaks access to device names with colons in them.
476 * Thanks to the brain-dead persistent naming schemes on udev-
477 * based Linux systems those actually are quite common.
479 drv1 = find_hdev_driver(filename);
480 if (drv1) {
481 return drv1;
484 if (!path_has_protocol(filename) || !allow_protocol_prefix) {
485 return &bdrv_file;
488 p = strchr(filename, ':');
489 assert(p != NULL);
490 len = p - filename;
491 if (len > sizeof(protocol) - 1)
492 len = sizeof(protocol) - 1;
493 memcpy(protocol, filename, len);
494 protocol[len] = '\0';
495 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
496 if (drv1->protocol_name &&
497 !strcmp(drv1->protocol_name, protocol)) {
498 return drv1;
502 error_setg(errp, "Unknown protocol '%s'", protocol);
503 return NULL;
507 * Guess image format by probing its contents.
508 * This is not a good idea when your image is raw (CVE-2008-2004), but
509 * we do it anyway for backward compatibility.
511 * @buf contains the image's first @buf_size bytes.
512 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
513 * but can be smaller if the image file is smaller)
514 * @filename is its filename.
516 * For all block drivers, call the bdrv_probe() method to get its
517 * probing score.
518 * Return the first block driver with the highest probing score.
520 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
521 const char *filename)
523 int score_max = 0, score;
524 BlockDriver *drv = NULL, *d;
526 QLIST_FOREACH(d, &bdrv_drivers, list) {
527 if (d->bdrv_probe) {
528 score = d->bdrv_probe(buf, buf_size, filename);
529 if (score > score_max) {
530 score_max = score;
531 drv = d;
536 return drv;
539 static int find_image_format(BdrvChild *file, const char *filename,
540 BlockDriver **pdrv, Error **errp)
542 BlockDriverState *bs = file->bs;
543 BlockDriver *drv;
544 uint8_t buf[BLOCK_PROBE_BUF_SIZE];
545 int ret = 0;
547 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
548 if (bdrv_is_sg(bs) || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) {
549 *pdrv = &bdrv_raw;
550 return ret;
553 ret = bdrv_pread(file, 0, buf, sizeof(buf));
554 if (ret < 0) {
555 error_setg_errno(errp, -ret, "Could not read image for determining its "
556 "format");
557 *pdrv = NULL;
558 return ret;
561 drv = bdrv_probe_all(buf, ret, filename);
562 if (!drv) {
563 error_setg(errp, "Could not determine image format: No compatible "
564 "driver found");
565 ret = -ENOENT;
567 *pdrv = drv;
568 return ret;
572 * Set the current 'total_sectors' value
573 * Return 0 on success, -errno on error.
575 static int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
577 BlockDriver *drv = bs->drv;
579 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
580 if (bdrv_is_sg(bs))
581 return 0;
583 /* query actual device if possible, otherwise just trust the hint */
584 if (drv->bdrv_getlength) {
585 int64_t length = drv->bdrv_getlength(bs);
586 if (length < 0) {
587 return length;
589 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE);
592 bs->total_sectors = hint;
593 return 0;
597 * Combines a QDict of new block driver @options with any missing options taken
598 * from @old_options, so that leaving out an option defaults to its old value.
600 static void bdrv_join_options(BlockDriverState *bs, QDict *options,
601 QDict *old_options)
603 if (bs->drv && bs->drv->bdrv_join_options) {
604 bs->drv->bdrv_join_options(options, old_options);
605 } else {
606 qdict_join(options, old_options, false);
611 * Set open flags for a given discard mode
613 * Return 0 on success, -1 if the discard mode was invalid.
615 int bdrv_parse_discard_flags(const char *mode, int *flags)
617 *flags &= ~BDRV_O_UNMAP;
619 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) {
620 /* do nothing */
621 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) {
622 *flags |= BDRV_O_UNMAP;
623 } else {
624 return -1;
627 return 0;
631 * Set open flags for a given cache mode
633 * Return 0 on success, -1 if the cache mode was invalid.
635 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough)
637 *flags &= ~BDRV_O_CACHE_MASK;
639 if (!strcmp(mode, "off") || !strcmp(mode, "none")) {
640 *writethrough = false;
641 *flags |= BDRV_O_NOCACHE;
642 } else if (!strcmp(mode, "directsync")) {
643 *writethrough = true;
644 *flags |= BDRV_O_NOCACHE;
645 } else if (!strcmp(mode, "writeback")) {
646 *writethrough = false;
647 } else if (!strcmp(mode, "unsafe")) {
648 *writethrough = false;
649 *flags |= BDRV_O_NO_FLUSH;
650 } else if (!strcmp(mode, "writethrough")) {
651 *writethrough = true;
652 } else {
653 return -1;
656 return 0;
659 static void bdrv_child_cb_drained_begin(BdrvChild *child)
661 BlockDriverState *bs = child->opaque;
662 bdrv_drained_begin(bs);
665 static void bdrv_child_cb_drained_end(BdrvChild *child)
667 BlockDriverState *bs = child->opaque;
668 bdrv_drained_end(bs);
672 * Returns the options and flags that a temporary snapshot should get, based on
673 * the originally requested flags (the originally requested image will have
674 * flags like a backing file)
676 static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
677 int parent_flags, QDict *parent_options)
679 *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY;
681 /* For temporary files, unconditional cache=unsafe is fine */
682 qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off");
683 qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
685 /* aio=native doesn't work for cache.direct=off, so disable it for the
686 * temporary snapshot */
687 *child_flags &= ~BDRV_O_NATIVE_AIO;
691 * Returns the options and flags that bs->file should get if a protocol driver
692 * is expected, based on the given options and flags for the parent BDS
694 static void bdrv_inherited_options(int *child_flags, QDict *child_options,
695 int parent_flags, QDict *parent_options)
697 int flags = parent_flags;
699 /* Enable protocol handling, disable format probing for bs->file */
700 flags |= BDRV_O_PROTOCOL;
702 /* If the cache mode isn't explicitly set, inherit direct and no-flush from
703 * the parent. */
704 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
705 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
707 /* Our block drivers take care to send flushes and respect unmap policy,
708 * so we can default to enable both on lower layers regardless of the
709 * corresponding parent options. */
710 flags |= BDRV_O_UNMAP;
712 /* Clear flags that only apply to the top layer */
713 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ |
714 BDRV_O_NO_IO);
716 *child_flags = flags;
719 const BdrvChildRole child_file = {
720 .inherit_options = bdrv_inherited_options,
721 .drained_begin = bdrv_child_cb_drained_begin,
722 .drained_end = bdrv_child_cb_drained_end,
726 * Returns the options and flags that bs->file should get if the use of formats
727 * (and not only protocols) is permitted for it, based on the given options and
728 * flags for the parent BDS
730 static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options,
731 int parent_flags, QDict *parent_options)
733 child_file.inherit_options(child_flags, child_options,
734 parent_flags, parent_options);
736 *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO);
739 const BdrvChildRole child_format = {
740 .inherit_options = bdrv_inherited_fmt_options,
741 .drained_begin = bdrv_child_cb_drained_begin,
742 .drained_end = bdrv_child_cb_drained_end,
746 * Returns the options and flags that bs->backing should get, based on the
747 * given options and flags for the parent BDS
749 static void bdrv_backing_options(int *child_flags, QDict *child_options,
750 int parent_flags, QDict *parent_options)
752 int flags = parent_flags;
754 /* The cache mode is inherited unmodified for backing files; except WCE,
755 * which is only applied on the top level (BlockBackend) */
756 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
757 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
759 /* backing files always opened read-only */
760 flags &= ~(BDRV_O_RDWR | BDRV_O_COPY_ON_READ);
762 /* snapshot=on is handled on the top layer */
763 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY);
765 *child_flags = flags;
768 static const BdrvChildRole child_backing = {
769 .inherit_options = bdrv_backing_options,
770 .drained_begin = bdrv_child_cb_drained_begin,
771 .drained_end = bdrv_child_cb_drained_end,
774 static int bdrv_open_flags(BlockDriverState *bs, int flags)
776 int open_flags = flags;
779 * Clear flags that are internal to the block layer before opening the
780 * image.
782 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL);
785 * Snapshots should be writable.
787 if (flags & BDRV_O_TEMPORARY) {
788 open_flags |= BDRV_O_RDWR;
791 return open_flags;
794 static void update_flags_from_options(int *flags, QemuOpts *opts)
796 *flags &= ~BDRV_O_CACHE_MASK;
798 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_NO_FLUSH));
799 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
800 *flags |= BDRV_O_NO_FLUSH;
803 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT));
804 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_DIRECT, false)) {
805 *flags |= BDRV_O_NOCACHE;
809 static void update_options_from_flags(QDict *options, int flags)
811 if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) {
812 qdict_put(options, BDRV_OPT_CACHE_DIRECT,
813 qbool_from_bool(flags & BDRV_O_NOCACHE));
815 if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) {
816 qdict_put(options, BDRV_OPT_CACHE_NO_FLUSH,
817 qbool_from_bool(flags & BDRV_O_NO_FLUSH));
821 static void bdrv_assign_node_name(BlockDriverState *bs,
822 const char *node_name,
823 Error **errp)
825 char *gen_node_name = NULL;
827 if (!node_name) {
828 node_name = gen_node_name = id_generate(ID_BLOCK);
829 } else if (!id_wellformed(node_name)) {
831 * Check for empty string or invalid characters, but not if it is
832 * generated (generated names use characters not available to the user)
834 error_setg(errp, "Invalid node name");
835 return;
838 /* takes care of avoiding namespaces collisions */
839 if (blk_by_name(node_name)) {
840 error_setg(errp, "node-name=%s is conflicting with a device id",
841 node_name);
842 goto out;
845 /* takes care of avoiding duplicates node names */
846 if (bdrv_find_node(node_name)) {
847 error_setg(errp, "Duplicate node name");
848 goto out;
851 /* copy node name into the bs and insert it into the graph list */
852 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
853 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
854 out:
855 g_free(gen_node_name);
858 static QemuOptsList bdrv_runtime_opts = {
859 .name = "bdrv_common",
860 .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head),
861 .desc = {
863 .name = "node-name",
864 .type = QEMU_OPT_STRING,
865 .help = "Node name of the block device node",
868 .name = "driver",
869 .type = QEMU_OPT_STRING,
870 .help = "Block driver to use for the node",
873 .name = BDRV_OPT_CACHE_DIRECT,
874 .type = QEMU_OPT_BOOL,
875 .help = "Bypass software writeback cache on the host",
878 .name = BDRV_OPT_CACHE_NO_FLUSH,
879 .type = QEMU_OPT_BOOL,
880 .help = "Ignore flush requests",
882 { /* end of list */ }
887 * Common part for opening disk images and files
889 * Removes all processed options from *options.
891 static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file,
892 QDict *options, Error **errp)
894 int ret, open_flags;
895 const char *filename;
896 const char *driver_name = NULL;
897 const char *node_name = NULL;
898 QemuOpts *opts;
899 BlockDriver *drv;
900 Error *local_err = NULL;
902 assert(bs->file == NULL);
903 assert(options != NULL && bs->options != options);
905 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
906 qemu_opts_absorb_qdict(opts, options, &local_err);
907 if (local_err) {
908 error_propagate(errp, local_err);
909 ret = -EINVAL;
910 goto fail_opts;
913 driver_name = qemu_opt_get(opts, "driver");
914 drv = bdrv_find_format(driver_name);
915 assert(drv != NULL);
917 if (file != NULL) {
918 filename = file->bs->filename;
919 } else {
920 filename = qdict_get_try_str(options, "filename");
923 if (drv->bdrv_needs_filename && !filename) {
924 error_setg(errp, "The '%s' block driver requires a file name",
925 drv->format_name);
926 ret = -EINVAL;
927 goto fail_opts;
930 trace_bdrv_open_common(bs, filename ?: "", bs->open_flags,
931 drv->format_name);
933 node_name = qemu_opt_get(opts, "node-name");
934 bdrv_assign_node_name(bs, node_name, &local_err);
935 if (local_err) {
936 error_propagate(errp, local_err);
937 ret = -EINVAL;
938 goto fail_opts;
941 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
943 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
944 error_setg(errp,
945 !bs->read_only && bdrv_is_whitelisted(drv, true)
946 ? "Driver '%s' can only be used for read-only devices"
947 : "Driver '%s' is not whitelisted",
948 drv->format_name);
949 ret = -ENOTSUP;
950 goto fail_opts;
953 assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */
954 if (bs->open_flags & BDRV_O_COPY_ON_READ) {
955 if (!bs->read_only) {
956 bdrv_enable_copy_on_read(bs);
957 } else {
958 error_setg(errp, "Can't use copy-on-read on read-only device");
959 ret = -EINVAL;
960 goto fail_opts;
964 if (filename != NULL) {
965 pstrcpy(bs->filename, sizeof(bs->filename), filename);
966 } else {
967 bs->filename[0] = '\0';
969 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename);
971 bs->drv = drv;
972 bs->opaque = g_malloc0(drv->instance_size);
974 /* Apply cache mode options */
975 update_flags_from_options(&bs->open_flags, opts);
977 /* Open the image, either directly or using a protocol */
978 open_flags = bdrv_open_flags(bs, bs->open_flags);
979 if (drv->bdrv_file_open) {
980 assert(file == NULL);
981 assert(!drv->bdrv_needs_filename || filename != NULL);
982 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err);
983 } else {
984 if (file == NULL) {
985 error_setg(errp, "Can't use '%s' as a block driver for the "
986 "protocol level", drv->format_name);
987 ret = -EINVAL;
988 goto free_and_fail;
990 bs->file = file;
991 ret = drv->bdrv_open(bs, options, open_flags, &local_err);
994 if (ret < 0) {
995 if (local_err) {
996 error_propagate(errp, local_err);
997 } else if (bs->filename[0]) {
998 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename);
999 } else {
1000 error_setg_errno(errp, -ret, "Could not open image");
1002 goto free_and_fail;
1005 ret = refresh_total_sectors(bs, bs->total_sectors);
1006 if (ret < 0) {
1007 error_setg_errno(errp, -ret, "Could not refresh total sector count");
1008 goto free_and_fail;
1011 bdrv_refresh_limits(bs, &local_err);
1012 if (local_err) {
1013 error_propagate(errp, local_err);
1014 ret = -EINVAL;
1015 goto free_and_fail;
1018 assert(bdrv_opt_mem_align(bs) != 0);
1019 assert(bdrv_min_mem_align(bs) != 0);
1020 assert(is_power_of_2(bs->bl.request_alignment));
1022 qemu_opts_del(opts);
1023 return 0;
1025 free_and_fail:
1026 bs->file = NULL;
1027 g_free(bs->opaque);
1028 bs->opaque = NULL;
1029 bs->drv = NULL;
1030 fail_opts:
1031 qemu_opts_del(opts);
1032 return ret;
1035 static QDict *parse_json_filename(const char *filename, Error **errp)
1037 QObject *options_obj;
1038 QDict *options;
1039 int ret;
1041 ret = strstart(filename, "json:", &filename);
1042 assert(ret);
1044 options_obj = qobject_from_json(filename);
1045 if (!options_obj) {
1046 error_setg(errp, "Could not parse the JSON options");
1047 return NULL;
1050 if (qobject_type(options_obj) != QTYPE_QDICT) {
1051 qobject_decref(options_obj);
1052 error_setg(errp, "Invalid JSON object given");
1053 return NULL;
1056 options = qobject_to_qdict(options_obj);
1057 qdict_flatten(options);
1059 return options;
1062 static void parse_json_protocol(QDict *options, const char **pfilename,
1063 Error **errp)
1065 QDict *json_options;
1066 Error *local_err = NULL;
1068 /* Parse json: pseudo-protocol */
1069 if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) {
1070 return;
1073 json_options = parse_json_filename(*pfilename, &local_err);
1074 if (local_err) {
1075 error_propagate(errp, local_err);
1076 return;
1079 /* Options given in the filename have lower priority than options
1080 * specified directly */
1081 qdict_join(options, json_options, false);
1082 QDECREF(json_options);
1083 *pfilename = NULL;
1087 * Fills in default options for opening images and converts the legacy
1088 * filename/flags pair to option QDict entries.
1089 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1090 * block driver has been specified explicitly.
1092 static int bdrv_fill_options(QDict **options, const char *filename,
1093 int *flags, Error **errp)
1095 const char *drvname;
1096 bool protocol = *flags & BDRV_O_PROTOCOL;
1097 bool parse_filename = false;
1098 BlockDriver *drv = NULL;
1099 Error *local_err = NULL;
1101 drvname = qdict_get_try_str(*options, "driver");
1102 if (drvname) {
1103 drv = bdrv_find_format(drvname);
1104 if (!drv) {
1105 error_setg(errp, "Unknown driver '%s'", drvname);
1106 return -ENOENT;
1108 /* If the user has explicitly specified the driver, this choice should
1109 * override the BDRV_O_PROTOCOL flag */
1110 protocol = drv->bdrv_file_open;
1113 if (protocol) {
1114 *flags |= BDRV_O_PROTOCOL;
1115 } else {
1116 *flags &= ~BDRV_O_PROTOCOL;
1119 /* Translate cache options from flags into options */
1120 update_options_from_flags(*options, *flags);
1122 /* Fetch the file name from the options QDict if necessary */
1123 if (protocol && filename) {
1124 if (!qdict_haskey(*options, "filename")) {
1125 qdict_put(*options, "filename", qstring_from_str(filename));
1126 parse_filename = true;
1127 } else {
1128 error_setg(errp, "Can't specify 'file' and 'filename' options at "
1129 "the same time");
1130 return -EINVAL;
1134 /* Find the right block driver */
1135 filename = qdict_get_try_str(*options, "filename");
1137 if (!drvname && protocol) {
1138 if (filename) {
1139 drv = bdrv_find_protocol(filename, parse_filename, errp);
1140 if (!drv) {
1141 return -EINVAL;
1144 drvname = drv->format_name;
1145 qdict_put(*options, "driver", qstring_from_str(drvname));
1146 } else {
1147 error_setg(errp, "Must specify either driver or file");
1148 return -EINVAL;
1152 assert(drv || !protocol);
1154 /* Driver-specific filename parsing */
1155 if (drv && drv->bdrv_parse_filename && parse_filename) {
1156 drv->bdrv_parse_filename(filename, *options, &local_err);
1157 if (local_err) {
1158 error_propagate(errp, local_err);
1159 return -EINVAL;
1162 if (!drv->bdrv_needs_filename) {
1163 qdict_del(*options, "filename");
1167 return 0;
1170 static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
1172 BlockDriverState *old_bs = child->bs;
1174 if (old_bs) {
1175 if (old_bs->quiesce_counter && child->role->drained_end) {
1176 child->role->drained_end(child);
1178 QLIST_REMOVE(child, next_parent);
1181 child->bs = new_bs;
1183 if (new_bs) {
1184 QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
1185 if (new_bs->quiesce_counter && child->role->drained_begin) {
1186 child->role->drained_begin(child);
1191 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
1192 const char *child_name,
1193 const BdrvChildRole *child_role,
1194 void *opaque)
1196 BdrvChild *child = g_new(BdrvChild, 1);
1197 *child = (BdrvChild) {
1198 .bs = NULL,
1199 .name = g_strdup(child_name),
1200 .role = child_role,
1201 .opaque = opaque,
1204 bdrv_replace_child(child, child_bs);
1206 return child;
1209 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
1210 BlockDriverState *child_bs,
1211 const char *child_name,
1212 const BdrvChildRole *child_role)
1214 BdrvChild *child = bdrv_root_attach_child(child_bs, child_name, child_role,
1215 parent_bs);
1216 QLIST_INSERT_HEAD(&parent_bs->children, child, next);
1217 return child;
1220 static void bdrv_detach_child(BdrvChild *child)
1222 if (child->next.le_prev) {
1223 QLIST_REMOVE(child, next);
1224 child->next.le_prev = NULL;
1227 bdrv_replace_child(child, NULL);
1229 g_free(child->name);
1230 g_free(child);
1233 void bdrv_root_unref_child(BdrvChild *child)
1235 BlockDriverState *child_bs;
1237 child_bs = child->bs;
1238 bdrv_detach_child(child);
1239 bdrv_unref(child_bs);
1242 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child)
1244 if (child == NULL) {
1245 return;
1248 if (child->bs->inherits_from == parent) {
1249 child->bs->inherits_from = NULL;
1252 bdrv_root_unref_child(child);
1256 static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load)
1258 BdrvChild *c;
1259 QLIST_FOREACH(c, &bs->parents, next_parent) {
1260 if (c->role->change_media) {
1261 c->role->change_media(c, load);
1266 static void bdrv_parent_cb_resize(BlockDriverState *bs)
1268 BdrvChild *c;
1269 QLIST_FOREACH(c, &bs->parents, next_parent) {
1270 if (c->role->resize) {
1271 c->role->resize(c);
1277 * Sets the backing file link of a BDS. A new reference is created; callers
1278 * which don't need their own reference any more must call bdrv_unref().
1280 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd)
1282 if (backing_hd) {
1283 bdrv_ref(backing_hd);
1286 if (bs->backing) {
1287 assert(bs->backing_blocker);
1288 bdrv_op_unblock_all(bs->backing->bs, bs->backing_blocker);
1289 bdrv_unref_child(bs, bs->backing);
1290 } else if (backing_hd) {
1291 error_setg(&bs->backing_blocker,
1292 "node is used as backing hd of '%s'",
1293 bdrv_get_device_or_node_name(bs));
1296 if (!backing_hd) {
1297 error_free(bs->backing_blocker);
1298 bs->backing_blocker = NULL;
1299 bs->backing = NULL;
1300 goto out;
1302 bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing);
1303 bs->open_flags &= ~BDRV_O_NO_BACKING;
1304 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_hd->filename);
1305 pstrcpy(bs->backing_format, sizeof(bs->backing_format),
1306 backing_hd->drv ? backing_hd->drv->format_name : "");
1308 bdrv_op_block_all(backing_hd, bs->backing_blocker);
1309 /* Otherwise we won't be able to commit due to check in bdrv_commit */
1310 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,
1311 bs->backing_blocker);
1312 out:
1313 bdrv_refresh_limits(bs, NULL);
1317 * Opens the backing file for a BlockDriverState if not yet open
1319 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
1320 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
1321 * itself, all options starting with "${bdref_key}." are considered part of the
1322 * BlockdevRef.
1324 * TODO Can this be unified with bdrv_open_image()?
1326 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
1327 const char *bdref_key, Error **errp)
1329 char *backing_filename = g_malloc0(PATH_MAX);
1330 char *bdref_key_dot;
1331 const char *reference = NULL;
1332 int ret = 0;
1333 BlockDriverState *backing_hd;
1334 QDict *options;
1335 QDict *tmp_parent_options = NULL;
1336 Error *local_err = NULL;
1338 if (bs->backing != NULL) {
1339 goto free_exit;
1342 /* NULL means an empty set of options */
1343 if (parent_options == NULL) {
1344 tmp_parent_options = qdict_new();
1345 parent_options = tmp_parent_options;
1348 bs->open_flags &= ~BDRV_O_NO_BACKING;
1350 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
1351 qdict_extract_subqdict(parent_options, &options, bdref_key_dot);
1352 g_free(bdref_key_dot);
1354 reference = qdict_get_try_str(parent_options, bdref_key);
1355 if (reference || qdict_haskey(options, "file.filename")) {
1356 backing_filename[0] = '\0';
1357 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
1358 QDECREF(options);
1359 goto free_exit;
1360 } else {
1361 bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX,
1362 &local_err);
1363 if (local_err) {
1364 ret = -EINVAL;
1365 error_propagate(errp, local_err);
1366 QDECREF(options);
1367 goto free_exit;
1371 if (!bs->drv || !bs->drv->supports_backing) {
1372 ret = -EINVAL;
1373 error_setg(errp, "Driver doesn't support backing files");
1374 QDECREF(options);
1375 goto free_exit;
1378 if (bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) {
1379 qdict_put(options, "driver", qstring_from_str(bs->backing_format));
1382 backing_hd = bdrv_open_inherit(*backing_filename ? backing_filename : NULL,
1383 reference, options, 0, bs, &child_backing,
1384 errp);
1385 if (!backing_hd) {
1386 bs->open_flags |= BDRV_O_NO_BACKING;
1387 error_prepend(errp, "Could not open backing file: ");
1388 ret = -EINVAL;
1389 goto free_exit;
1392 /* Hook up the backing file link; drop our reference, bs owns the
1393 * backing_hd reference now */
1394 bdrv_set_backing_hd(bs, backing_hd);
1395 bdrv_unref(backing_hd);
1397 qdict_del(parent_options, bdref_key);
1399 free_exit:
1400 g_free(backing_filename);
1401 QDECREF(tmp_parent_options);
1402 return ret;
1406 * Opens a disk image whose options are given as BlockdevRef in another block
1407 * device's options.
1409 * If allow_none is true, no image will be opened if filename is false and no
1410 * BlockdevRef is given. NULL will be returned, but errp remains unset.
1412 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
1413 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
1414 * itself, all options starting with "${bdref_key}." are considered part of the
1415 * BlockdevRef.
1417 * The BlockdevRef will be removed from the options QDict.
1419 BdrvChild *bdrv_open_child(const char *filename,
1420 QDict *options, const char *bdref_key,
1421 BlockDriverState* parent,
1422 const BdrvChildRole *child_role,
1423 bool allow_none, Error **errp)
1425 BdrvChild *c = NULL;
1426 BlockDriverState *bs;
1427 QDict *image_options;
1428 char *bdref_key_dot;
1429 const char *reference;
1431 assert(child_role != NULL);
1433 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
1434 qdict_extract_subqdict(options, &image_options, bdref_key_dot);
1435 g_free(bdref_key_dot);
1437 reference = qdict_get_try_str(options, bdref_key);
1438 if (!filename && !reference && !qdict_size(image_options)) {
1439 if (!allow_none) {
1440 error_setg(errp, "A block device must be specified for \"%s\"",
1441 bdref_key);
1443 QDECREF(image_options);
1444 goto done;
1447 bs = bdrv_open_inherit(filename, reference, image_options, 0,
1448 parent, child_role, errp);
1449 if (!bs) {
1450 goto done;
1453 c = bdrv_attach_child(parent, bs, bdref_key, child_role);
1455 done:
1456 qdict_del(options, bdref_key);
1457 return c;
1460 static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
1461 int flags,
1462 QDict *snapshot_options,
1463 Error **errp)
1465 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
1466 char *tmp_filename = g_malloc0(PATH_MAX + 1);
1467 int64_t total_size;
1468 QemuOpts *opts = NULL;
1469 BlockDriverState *bs_snapshot;
1470 int ret;
1472 /* if snapshot, we create a temporary backing file and open it
1473 instead of opening 'filename' directly */
1475 /* Get the required size from the image */
1476 total_size = bdrv_getlength(bs);
1477 if (total_size < 0) {
1478 error_setg_errno(errp, -total_size, "Could not get image size");
1479 goto out;
1482 /* Create the temporary image */
1483 ret = get_tmp_filename(tmp_filename, PATH_MAX + 1);
1484 if (ret < 0) {
1485 error_setg_errno(errp, -ret, "Could not get temporary filename");
1486 goto out;
1489 opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0,
1490 &error_abort);
1491 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort);
1492 ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp);
1493 qemu_opts_del(opts);
1494 if (ret < 0) {
1495 error_prepend(errp, "Could not create temporary overlay '%s': ",
1496 tmp_filename);
1497 goto out;
1500 /* Prepare options QDict for the temporary file */
1501 qdict_put(snapshot_options, "file.driver",
1502 qstring_from_str("file"));
1503 qdict_put(snapshot_options, "file.filename",
1504 qstring_from_str(tmp_filename));
1505 qdict_put(snapshot_options, "driver",
1506 qstring_from_str("qcow2"));
1508 bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp);
1509 snapshot_options = NULL;
1510 if (!bs_snapshot) {
1511 ret = -EINVAL;
1512 goto out;
1515 /* bdrv_append() consumes a strong reference to bs_snapshot (i.e. it will
1516 * call bdrv_unref() on it), so in order to be able to return one, we have
1517 * to increase bs_snapshot's refcount here */
1518 bdrv_ref(bs_snapshot);
1519 bdrv_append(bs_snapshot, bs);
1521 g_free(tmp_filename);
1522 return bs_snapshot;
1524 out:
1525 QDECREF(snapshot_options);
1526 g_free(tmp_filename);
1527 return NULL;
1531 * Opens a disk image (raw, qcow2, vmdk, ...)
1533 * options is a QDict of options to pass to the block drivers, or NULL for an
1534 * empty set of options. The reference to the QDict belongs to the block layer
1535 * after the call (even on failure), so if the caller intends to reuse the
1536 * dictionary, it needs to use QINCREF() before calling bdrv_open.
1538 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
1539 * If it is not NULL, the referenced BDS will be reused.
1541 * The reference parameter may be used to specify an existing block device which
1542 * should be opened. If specified, neither options nor a filename may be given,
1543 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
1545 static BlockDriverState *bdrv_open_inherit(const char *filename,
1546 const char *reference,
1547 QDict *options, int flags,
1548 BlockDriverState *parent,
1549 const BdrvChildRole *child_role,
1550 Error **errp)
1552 int ret;
1553 BdrvChild *file = NULL;
1554 BlockDriverState *bs;
1555 BlockDriver *drv = NULL;
1556 const char *drvname;
1557 const char *backing;
1558 Error *local_err = NULL;
1559 QDict *snapshot_options = NULL;
1560 int snapshot_flags = 0;
1562 assert(!child_role || !flags);
1563 assert(!child_role == !parent);
1565 if (reference) {
1566 bool options_non_empty = options ? qdict_size(options) : false;
1567 QDECREF(options);
1569 if (filename || options_non_empty) {
1570 error_setg(errp, "Cannot reference an existing block device with "
1571 "additional options or a new filename");
1572 return NULL;
1575 bs = bdrv_lookup_bs(reference, reference, errp);
1576 if (!bs) {
1577 return NULL;
1580 bdrv_ref(bs);
1581 return bs;
1584 bs = bdrv_new();
1586 /* NULL means an empty set of options */
1587 if (options == NULL) {
1588 options = qdict_new();
1591 /* json: syntax counts as explicit options, as if in the QDict */
1592 parse_json_protocol(options, &filename, &local_err);
1593 if (local_err) {
1594 goto fail;
1597 bs->explicit_options = qdict_clone_shallow(options);
1599 if (child_role) {
1600 bs->inherits_from = parent;
1601 child_role->inherit_options(&flags, options,
1602 parent->open_flags, parent->options);
1605 ret = bdrv_fill_options(&options, filename, &flags, &local_err);
1606 if (local_err) {
1607 goto fail;
1610 bs->open_flags = flags;
1611 bs->options = options;
1612 options = qdict_clone_shallow(options);
1614 /* Find the right image format driver */
1615 drvname = qdict_get_try_str(options, "driver");
1616 if (drvname) {
1617 drv = bdrv_find_format(drvname);
1618 if (!drv) {
1619 error_setg(errp, "Unknown driver: '%s'", drvname);
1620 goto fail;
1624 assert(drvname || !(flags & BDRV_O_PROTOCOL));
1626 backing = qdict_get_try_str(options, "backing");
1627 if (backing && *backing == '\0') {
1628 flags |= BDRV_O_NO_BACKING;
1629 qdict_del(options, "backing");
1632 /* Open image file without format layer */
1633 if ((flags & BDRV_O_PROTOCOL) == 0) {
1634 if (flags & BDRV_O_RDWR) {
1635 flags |= BDRV_O_ALLOW_RDWR;
1637 if (flags & BDRV_O_SNAPSHOT) {
1638 snapshot_options = qdict_new();
1639 bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options,
1640 flags, options);
1641 bdrv_backing_options(&flags, options, flags, options);
1644 bs->open_flags = flags;
1646 file = bdrv_open_child(filename, options, "file", bs,
1647 &child_file, true, &local_err);
1648 if (local_err) {
1649 goto fail;
1653 /* Image format probing */
1654 bs->probed = !drv;
1655 if (!drv && file) {
1656 ret = find_image_format(file, filename, &drv, &local_err);
1657 if (ret < 0) {
1658 goto fail;
1661 * This option update would logically belong in bdrv_fill_options(),
1662 * but we first need to open bs->file for the probing to work, while
1663 * opening bs->file already requires the (mostly) final set of options
1664 * so that cache mode etc. can be inherited.
1666 * Adding the driver later is somewhat ugly, but it's not an option
1667 * that would ever be inherited, so it's correct. We just need to make
1668 * sure to update both bs->options (which has the full effective
1669 * options for bs) and options (which has file.* already removed).
1671 qdict_put(bs->options, "driver", qstring_from_str(drv->format_name));
1672 qdict_put(options, "driver", qstring_from_str(drv->format_name));
1673 } else if (!drv) {
1674 error_setg(errp, "Must specify either driver or file");
1675 goto fail;
1678 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
1679 assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open);
1680 /* file must be NULL if a protocol BDS is about to be created
1681 * (the inverse results in an error message from bdrv_open_common()) */
1682 assert(!(flags & BDRV_O_PROTOCOL) || !file);
1684 /* Open the image */
1685 ret = bdrv_open_common(bs, file, options, &local_err);
1686 if (ret < 0) {
1687 goto fail;
1690 if (file && (bs->file != file)) {
1691 bdrv_unref_child(bs, file);
1692 file = NULL;
1695 /* If there is a backing file, use it */
1696 if ((flags & BDRV_O_NO_BACKING) == 0) {
1697 ret = bdrv_open_backing_file(bs, options, "backing", &local_err);
1698 if (ret < 0) {
1699 goto close_and_fail;
1703 bdrv_refresh_filename(bs);
1705 /* Check if any unknown options were used */
1706 if (options && (qdict_size(options) != 0)) {
1707 const QDictEntry *entry = qdict_first(options);
1708 if (flags & BDRV_O_PROTOCOL) {
1709 error_setg(errp, "Block protocol '%s' doesn't support the option "
1710 "'%s'", drv->format_name, entry->key);
1711 } else {
1712 error_setg(errp,
1713 "Block format '%s' does not support the option '%s'",
1714 drv->format_name, entry->key);
1717 goto close_and_fail;
1720 if (!bdrv_key_required(bs)) {
1721 bdrv_parent_cb_change_media(bs, true);
1722 } else if (!runstate_check(RUN_STATE_PRELAUNCH)
1723 && !runstate_check(RUN_STATE_INMIGRATE)
1724 && !runstate_check(RUN_STATE_PAUSED)) { /* HACK */
1725 error_setg(errp,
1726 "Guest must be stopped for opening of encrypted image");
1727 goto close_and_fail;
1730 QDECREF(options);
1732 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
1733 * temporary snapshot afterwards. */
1734 if (snapshot_flags) {
1735 BlockDriverState *snapshot_bs;
1736 snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags,
1737 snapshot_options, &local_err);
1738 snapshot_options = NULL;
1739 if (local_err) {
1740 goto close_and_fail;
1742 /* We are not going to return bs but the overlay on top of it
1743 * (snapshot_bs); thus, we have to drop the strong reference to bs
1744 * (which we obtained by calling bdrv_new()). bs will not be deleted,
1745 * though, because the overlay still has a reference to it. */
1746 bdrv_unref(bs);
1747 bs = snapshot_bs;
1750 return bs;
1752 fail:
1753 if (file != NULL) {
1754 bdrv_unref_child(bs, file);
1756 QDECREF(snapshot_options);
1757 QDECREF(bs->explicit_options);
1758 QDECREF(bs->options);
1759 QDECREF(options);
1760 bs->options = NULL;
1761 bdrv_unref(bs);
1762 error_propagate(errp, local_err);
1763 return NULL;
1765 close_and_fail:
1766 bdrv_unref(bs);
1767 QDECREF(snapshot_options);
1768 QDECREF(options);
1769 error_propagate(errp, local_err);
1770 return NULL;
1773 BlockDriverState *bdrv_open(const char *filename, const char *reference,
1774 QDict *options, int flags, Error **errp)
1776 return bdrv_open_inherit(filename, reference, options, flags, NULL,
1777 NULL, errp);
1780 typedef struct BlockReopenQueueEntry {
1781 bool prepared;
1782 BDRVReopenState state;
1783 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry;
1784 } BlockReopenQueueEntry;
1787 * Adds a BlockDriverState to a simple queue for an atomic, transactional
1788 * reopen of multiple devices.
1790 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT
1791 * already performed, or alternatively may be NULL a new BlockReopenQueue will
1792 * be created and initialized. This newly created BlockReopenQueue should be
1793 * passed back in for subsequent calls that are intended to be of the same
1794 * atomic 'set'.
1796 * bs is the BlockDriverState to add to the reopen queue.
1798 * options contains the changed options for the associated bs
1799 * (the BlockReopenQueue takes ownership)
1801 * flags contains the open flags for the associated bs
1803 * returns a pointer to bs_queue, which is either the newly allocated
1804 * bs_queue, or the existing bs_queue being used.
1807 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
1808 BlockDriverState *bs,
1809 QDict *options,
1810 int flags,
1811 const BdrvChildRole *role,
1812 QDict *parent_options,
1813 int parent_flags)
1815 assert(bs != NULL);
1817 BlockReopenQueueEntry *bs_entry;
1818 BdrvChild *child;
1819 QDict *old_options, *explicit_options;
1821 if (bs_queue == NULL) {
1822 bs_queue = g_new0(BlockReopenQueue, 1);
1823 QSIMPLEQ_INIT(bs_queue);
1826 if (!options) {
1827 options = qdict_new();
1831 * Precedence of options:
1832 * 1. Explicitly passed in options (highest)
1833 * 2. Set in flags (only for top level)
1834 * 3. Retained from explicitly set options of bs
1835 * 4. Inherited from parent node
1836 * 5. Retained from effective options of bs
1839 if (!parent_options) {
1841 * Any setting represented by flags is always updated. If the
1842 * corresponding QDict option is set, it takes precedence. Otherwise
1843 * the flag is translated into a QDict option. The old setting of bs is
1844 * not considered.
1846 update_options_from_flags(options, flags);
1849 /* Old explicitly set values (don't overwrite by inherited value) */
1850 old_options = qdict_clone_shallow(bs->explicit_options);
1851 bdrv_join_options(bs, options, old_options);
1852 QDECREF(old_options);
1854 explicit_options = qdict_clone_shallow(options);
1856 /* Inherit from parent node */
1857 if (parent_options) {
1858 assert(!flags);
1859 role->inherit_options(&flags, options, parent_flags, parent_options);
1862 /* Old values are used for options that aren't set yet */
1863 old_options = qdict_clone_shallow(bs->options);
1864 bdrv_join_options(bs, options, old_options);
1865 QDECREF(old_options);
1867 /* bdrv_open() masks this flag out */
1868 flags &= ~BDRV_O_PROTOCOL;
1870 QLIST_FOREACH(child, &bs->children, next) {
1871 QDict *new_child_options;
1872 char *child_key_dot;
1874 /* reopen can only change the options of block devices that were
1875 * implicitly created and inherited options. For other (referenced)
1876 * block devices, a syntax like "backing.foo" results in an error. */
1877 if (child->bs->inherits_from != bs) {
1878 continue;
1881 child_key_dot = g_strdup_printf("%s.", child->name);
1882 qdict_extract_subqdict(options, &new_child_options, child_key_dot);
1883 g_free(child_key_dot);
1885 bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options, 0,
1886 child->role, options, flags);
1889 bs_entry = g_new0(BlockReopenQueueEntry, 1);
1890 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry);
1892 bs_entry->state.bs = bs;
1893 bs_entry->state.options = options;
1894 bs_entry->state.explicit_options = explicit_options;
1895 bs_entry->state.flags = flags;
1897 return bs_queue;
1900 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
1901 BlockDriverState *bs,
1902 QDict *options, int flags)
1904 return bdrv_reopen_queue_child(bs_queue, bs, options, flags,
1905 NULL, NULL, 0);
1909 * Reopen multiple BlockDriverStates atomically & transactionally.
1911 * The queue passed in (bs_queue) must have been built up previous
1912 * via bdrv_reopen_queue().
1914 * Reopens all BDS specified in the queue, with the appropriate
1915 * flags. All devices are prepared for reopen, and failure of any
1916 * device will cause all device changes to be abandonded, and intermediate
1917 * data cleaned up.
1919 * If all devices prepare successfully, then the changes are committed
1920 * to all devices.
1923 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
1925 int ret = -1;
1926 BlockReopenQueueEntry *bs_entry, *next;
1927 Error *local_err = NULL;
1929 assert(bs_queue != NULL);
1931 bdrv_drain_all();
1933 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
1934 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) {
1935 error_propagate(errp, local_err);
1936 goto cleanup;
1938 bs_entry->prepared = true;
1941 /* If we reach this point, we have success and just need to apply the
1942 * changes
1944 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
1945 bdrv_reopen_commit(&bs_entry->state);
1948 ret = 0;
1950 cleanup:
1951 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
1952 if (ret && bs_entry->prepared) {
1953 bdrv_reopen_abort(&bs_entry->state);
1954 } else if (ret) {
1955 QDECREF(bs_entry->state.explicit_options);
1957 QDECREF(bs_entry->state.options);
1958 g_free(bs_entry);
1960 g_free(bs_queue);
1961 return ret;
1965 /* Reopen a single BlockDriverState with the specified flags. */
1966 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp)
1968 int ret = -1;
1969 Error *local_err = NULL;
1970 BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags);
1972 ret = bdrv_reopen_multiple(queue, &local_err);
1973 if (local_err != NULL) {
1974 error_propagate(errp, local_err);
1976 return ret;
1981 * Prepares a BlockDriverState for reopen. All changes are staged in the
1982 * 'opaque' field of the BDRVReopenState, which is used and allocated by
1983 * the block driver layer .bdrv_reopen_prepare()
1985 * bs is the BlockDriverState to reopen
1986 * flags are the new open flags
1987 * queue is the reopen queue
1989 * Returns 0 on success, non-zero on error. On error errp will be set
1990 * as well.
1992 * On failure, bdrv_reopen_abort() will be called to clean up any data.
1993 * It is the responsibility of the caller to then call the abort() or
1994 * commit() for any other BDS that have been left in a prepare() state
1997 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
1998 Error **errp)
2000 int ret = -1;
2001 Error *local_err = NULL;
2002 BlockDriver *drv;
2003 QemuOpts *opts;
2004 const char *value;
2006 assert(reopen_state != NULL);
2007 assert(reopen_state->bs->drv != NULL);
2008 drv = reopen_state->bs->drv;
2010 /* Process generic block layer options */
2011 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
2012 qemu_opts_absorb_qdict(opts, reopen_state->options, &local_err);
2013 if (local_err) {
2014 error_propagate(errp, local_err);
2015 ret = -EINVAL;
2016 goto error;
2019 update_flags_from_options(&reopen_state->flags, opts);
2021 /* node-name and driver must be unchanged. Put them back into the QDict, so
2022 * that they are checked at the end of this function. */
2023 value = qemu_opt_get(opts, "node-name");
2024 if (value) {
2025 qdict_put(reopen_state->options, "node-name", qstring_from_str(value));
2028 value = qemu_opt_get(opts, "driver");
2029 if (value) {
2030 qdict_put(reopen_state->options, "driver", qstring_from_str(value));
2033 /* if we are to stay read-only, do not allow permission change
2034 * to r/w */
2035 if (!(reopen_state->bs->open_flags & BDRV_O_ALLOW_RDWR) &&
2036 reopen_state->flags & BDRV_O_RDWR) {
2037 error_setg(errp, "Node '%s' is read only",
2038 bdrv_get_device_or_node_name(reopen_state->bs));
2039 goto error;
2043 ret = bdrv_flush(reopen_state->bs);
2044 if (ret) {
2045 error_setg_errno(errp, -ret, "Error flushing drive");
2046 goto error;
2049 if (drv->bdrv_reopen_prepare) {
2050 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err);
2051 if (ret) {
2052 if (local_err != NULL) {
2053 error_propagate(errp, local_err);
2054 } else {
2055 error_setg(errp, "failed while preparing to reopen image '%s'",
2056 reopen_state->bs->filename);
2058 goto error;
2060 } else {
2061 /* It is currently mandatory to have a bdrv_reopen_prepare()
2062 * handler for each supported drv. */
2063 error_setg(errp, "Block format '%s' used by node '%s' "
2064 "does not support reopening files", drv->format_name,
2065 bdrv_get_device_or_node_name(reopen_state->bs));
2066 ret = -1;
2067 goto error;
2070 /* Options that are not handled are only okay if they are unchanged
2071 * compared to the old state. It is expected that some options are only
2072 * used for the initial open, but not reopen (e.g. filename) */
2073 if (qdict_size(reopen_state->options)) {
2074 const QDictEntry *entry = qdict_first(reopen_state->options);
2076 do {
2077 QString *new_obj = qobject_to_qstring(entry->value);
2078 const char *new = qstring_get_str(new_obj);
2079 const char *old = qdict_get_try_str(reopen_state->bs->options,
2080 entry->key);
2082 if (!old || strcmp(new, old)) {
2083 error_setg(errp, "Cannot change the option '%s'", entry->key);
2084 ret = -EINVAL;
2085 goto error;
2087 } while ((entry = qdict_next(reopen_state->options, entry)));
2090 ret = 0;
2092 error:
2093 qemu_opts_del(opts);
2094 return ret;
2098 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
2099 * makes them final by swapping the staging BlockDriverState contents into
2100 * the active BlockDriverState contents.
2102 void bdrv_reopen_commit(BDRVReopenState *reopen_state)
2104 BlockDriver *drv;
2106 assert(reopen_state != NULL);
2107 drv = reopen_state->bs->drv;
2108 assert(drv != NULL);
2110 /* If there are any driver level actions to take */
2111 if (drv->bdrv_reopen_commit) {
2112 drv->bdrv_reopen_commit(reopen_state);
2115 /* set BDS specific flags now */
2116 QDECREF(reopen_state->bs->explicit_options);
2118 reopen_state->bs->explicit_options = reopen_state->explicit_options;
2119 reopen_state->bs->open_flags = reopen_state->flags;
2120 reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
2122 bdrv_refresh_limits(reopen_state->bs, NULL);
2126 * Abort the reopen, and delete and free the staged changes in
2127 * reopen_state
2129 void bdrv_reopen_abort(BDRVReopenState *reopen_state)
2131 BlockDriver *drv;
2133 assert(reopen_state != NULL);
2134 drv = reopen_state->bs->drv;
2135 assert(drv != NULL);
2137 if (drv->bdrv_reopen_abort) {
2138 drv->bdrv_reopen_abort(reopen_state);
2141 QDECREF(reopen_state->explicit_options);
2145 static void bdrv_close(BlockDriverState *bs)
2147 BdrvAioNotifier *ban, *ban_next;
2149 assert(!bs->job);
2150 assert(!bs->refcnt);
2152 bdrv_drained_begin(bs); /* complete I/O */
2153 bdrv_flush(bs);
2154 bdrv_drain(bs); /* in case flush left pending I/O */
2156 bdrv_release_named_dirty_bitmaps(bs);
2157 assert(QLIST_EMPTY(&bs->dirty_bitmaps));
2159 if (bs->drv) {
2160 BdrvChild *child, *next;
2162 bs->drv->bdrv_close(bs);
2163 bs->drv = NULL;
2165 bdrv_set_backing_hd(bs, NULL);
2167 if (bs->file != NULL) {
2168 bdrv_unref_child(bs, bs->file);
2169 bs->file = NULL;
2172 QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
2173 /* TODO Remove bdrv_unref() from drivers' close function and use
2174 * bdrv_unref_child() here */
2175 if (child->bs->inherits_from == bs) {
2176 child->bs->inherits_from = NULL;
2178 bdrv_detach_child(child);
2181 g_free(bs->opaque);
2182 bs->opaque = NULL;
2183 bs->copy_on_read = 0;
2184 bs->backing_file[0] = '\0';
2185 bs->backing_format[0] = '\0';
2186 bs->total_sectors = 0;
2187 bs->encrypted = false;
2188 bs->valid_key = false;
2189 bs->sg = false;
2190 QDECREF(bs->options);
2191 QDECREF(bs->explicit_options);
2192 bs->options = NULL;
2193 QDECREF(bs->full_open_options);
2194 bs->full_open_options = NULL;
2197 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
2198 g_free(ban);
2200 QLIST_INIT(&bs->aio_notifiers);
2201 bdrv_drained_end(bs);
2204 void bdrv_close_all(void)
2206 block_job_cancel_sync_all();
2208 /* Drop references from requests still in flight, such as canceled block
2209 * jobs whose AIO context has not been polled yet */
2210 bdrv_drain_all();
2212 blk_remove_all_bs();
2213 blockdev_close_all_bdrv_states();
2215 assert(QTAILQ_EMPTY(&all_bdrv_states));
2218 static void change_parent_backing_link(BlockDriverState *from,
2219 BlockDriverState *to)
2221 BdrvChild *c, *next, *to_c;
2223 QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
2224 if (c->role == &child_backing) {
2225 /* @from is generally not allowed to be a backing file, except for
2226 * when @to is the overlay. In that case, @from may not be replaced
2227 * by @to as @to's backing node. */
2228 QLIST_FOREACH(to_c, &to->children, next) {
2229 if (to_c == c) {
2230 break;
2233 if (to_c) {
2234 continue;
2238 assert(c->role != &child_backing);
2239 bdrv_ref(to);
2240 bdrv_replace_child(c, to);
2241 bdrv_unref(from);
2246 * Add new bs contents at the top of an image chain while the chain is
2247 * live, while keeping required fields on the top layer.
2249 * This will modify the BlockDriverState fields, and swap contents
2250 * between bs_new and bs_top. Both bs_new and bs_top are modified.
2252 * bs_new must not be attached to a BlockBackend.
2254 * This function does not create any image files.
2256 * bdrv_append() takes ownership of a bs_new reference and unrefs it because
2257 * that's what the callers commonly need. bs_new will be referenced by the old
2258 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a
2259 * reference of its own, it must call bdrv_ref().
2261 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top)
2263 assert(!bdrv_requests_pending(bs_top));
2264 assert(!bdrv_requests_pending(bs_new));
2266 bdrv_ref(bs_top);
2268 change_parent_backing_link(bs_top, bs_new);
2269 bdrv_set_backing_hd(bs_new, bs_top);
2270 bdrv_unref(bs_top);
2272 /* bs_new is now referenced by its new parents, we don't need the
2273 * additional reference any more. */
2274 bdrv_unref(bs_new);
2277 void bdrv_replace_in_backing_chain(BlockDriverState *old, BlockDriverState *new)
2279 assert(!bdrv_requests_pending(old));
2280 assert(!bdrv_requests_pending(new));
2282 bdrv_ref(old);
2284 change_parent_backing_link(old, new);
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);
2327 * Return values:
2328 * 0 - success
2329 * -EINVAL - backing format specified, but no file
2330 * -ENOSPC - can't update the backing file because no space is left in the
2331 * image file header
2332 * -ENOTSUP - format driver doesn't support changing the backing file
2334 int bdrv_change_backing_file(BlockDriverState *bs,
2335 const char *backing_file, const char *backing_fmt)
2337 BlockDriver *drv = bs->drv;
2338 int ret;
2340 /* Backing file format doesn't make sense without a backing file */
2341 if (backing_fmt && !backing_file) {
2342 return -EINVAL;
2345 if (drv->bdrv_change_backing_file != NULL) {
2346 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
2347 } else {
2348 ret = -ENOTSUP;
2351 if (ret == 0) {
2352 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
2353 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
2355 return ret;
2359 * Finds the image layer in the chain that has 'bs' as its backing file.
2361 * active is the current topmost image.
2363 * Returns NULL if bs is not found in active's image chain,
2364 * or if active == bs.
2366 * Returns the bottommost base image if bs == NULL.
2368 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
2369 BlockDriverState *bs)
2371 while (active && bs != backing_bs(active)) {
2372 active = backing_bs(active);
2375 return active;
2378 /* Given a BDS, searches for the base layer. */
2379 BlockDriverState *bdrv_find_base(BlockDriverState *bs)
2381 return bdrv_find_overlay(bs, NULL);
2385 * Drops images above 'base' up to and including 'top', and sets the image
2386 * above 'top' to have base as its backing file.
2388 * Requires that the overlay to 'top' is opened r/w, so that the backing file
2389 * information in 'bs' can be properly updated.
2391 * E.g., this will convert the following chain:
2392 * bottom <- base <- intermediate <- top <- active
2394 * to
2396 * bottom <- base <- active
2398 * It is allowed for bottom==base, in which case it converts:
2400 * base <- intermediate <- top <- active
2402 * to
2404 * base <- active
2406 * If backing_file_str is non-NULL, it will be used when modifying top's
2407 * overlay image metadata.
2409 * Error conditions:
2410 * if active == top, that is considered an error
2413 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
2414 BlockDriverState *base, const char *backing_file_str)
2416 BlockDriverState *new_top_bs = NULL;
2417 int ret = -EIO;
2419 if (!top->drv || !base->drv) {
2420 goto exit;
2423 new_top_bs = bdrv_find_overlay(active, top);
2425 if (new_top_bs == NULL) {
2426 /* we could not find the image above 'top', this is an error */
2427 goto exit;
2430 /* special case of new_top_bs->backing->bs already pointing to base - nothing
2431 * to do, no intermediate images */
2432 if (backing_bs(new_top_bs) == base) {
2433 ret = 0;
2434 goto exit;
2437 /* Make sure that base is in the backing chain of top */
2438 if (!bdrv_chain_contains(top, base)) {
2439 goto exit;
2442 /* success - we can delete the intermediate states, and link top->base */
2443 backing_file_str = backing_file_str ? backing_file_str : base->filename;
2444 ret = bdrv_change_backing_file(new_top_bs, backing_file_str,
2445 base->drv ? base->drv->format_name : "");
2446 if (ret) {
2447 goto exit;
2449 bdrv_set_backing_hd(new_top_bs, base);
2451 ret = 0;
2452 exit:
2453 return ret;
2457 * Truncate file to 'offset' bytes (needed only for file protocols)
2459 int bdrv_truncate(BlockDriverState *bs, int64_t offset)
2461 BlockDriver *drv = bs->drv;
2462 int ret;
2463 if (!drv)
2464 return -ENOMEDIUM;
2465 if (!drv->bdrv_truncate)
2466 return -ENOTSUP;
2467 if (bs->read_only)
2468 return -EACCES;
2470 ret = drv->bdrv_truncate(bs, offset);
2471 if (ret == 0) {
2472 ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
2473 bdrv_dirty_bitmap_truncate(bs);
2474 bdrv_parent_cb_resize(bs);
2476 return ret;
2480 * Length of a allocated file in bytes. Sparse files are counted by actual
2481 * allocated space. Return < 0 if error or unknown.
2483 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs)
2485 BlockDriver *drv = bs->drv;
2486 if (!drv) {
2487 return -ENOMEDIUM;
2489 if (drv->bdrv_get_allocated_file_size) {
2490 return drv->bdrv_get_allocated_file_size(bs);
2492 if (bs->file) {
2493 return bdrv_get_allocated_file_size(bs->file->bs);
2495 return -ENOTSUP;
2499 * Return number of sectors on success, -errno on error.
2501 int64_t bdrv_nb_sectors(BlockDriverState *bs)
2503 BlockDriver *drv = bs->drv;
2505 if (!drv)
2506 return -ENOMEDIUM;
2508 if (drv->has_variable_length) {
2509 int ret = refresh_total_sectors(bs, bs->total_sectors);
2510 if (ret < 0) {
2511 return ret;
2514 return bs->total_sectors;
2518 * Return length in bytes on success, -errno on error.
2519 * The length is always a multiple of BDRV_SECTOR_SIZE.
2521 int64_t bdrv_getlength(BlockDriverState *bs)
2523 int64_t ret = bdrv_nb_sectors(bs);
2525 ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret;
2526 return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE;
2529 /* return 0 as number of sectors if no device present or error */
2530 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
2532 int64_t nb_sectors = bdrv_nb_sectors(bs);
2534 *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors;
2537 bool bdrv_is_read_only(BlockDriverState *bs)
2539 return bs->read_only;
2542 bool bdrv_is_sg(BlockDriverState *bs)
2544 return bs->sg;
2547 bool bdrv_is_encrypted(BlockDriverState *bs)
2549 if (bs->backing && bs->backing->bs->encrypted) {
2550 return true;
2552 return bs->encrypted;
2555 bool bdrv_key_required(BlockDriverState *bs)
2557 BdrvChild *backing = bs->backing;
2559 if (backing && backing->bs->encrypted && !backing->bs->valid_key) {
2560 return true;
2562 return (bs->encrypted && !bs->valid_key);
2565 int bdrv_set_key(BlockDriverState *bs, const char *key)
2567 int ret;
2568 if (bs->backing && bs->backing->bs->encrypted) {
2569 ret = bdrv_set_key(bs->backing->bs, key);
2570 if (ret < 0)
2571 return ret;
2572 if (!bs->encrypted)
2573 return 0;
2575 if (!bs->encrypted) {
2576 return -EINVAL;
2577 } else if (!bs->drv || !bs->drv->bdrv_set_key) {
2578 return -ENOMEDIUM;
2580 ret = bs->drv->bdrv_set_key(bs, key);
2581 if (ret < 0) {
2582 bs->valid_key = false;
2583 } else if (!bs->valid_key) {
2584 /* call the change callback now, we skipped it on open */
2585 bs->valid_key = true;
2586 bdrv_parent_cb_change_media(bs, true);
2588 return ret;
2592 * Provide an encryption key for @bs.
2593 * If @key is non-null:
2594 * If @bs is not encrypted, fail.
2595 * Else if the key is invalid, fail.
2596 * Else set @bs's key to @key, replacing the existing key, if any.
2597 * If @key is null:
2598 * If @bs is encrypted and still lacks a key, fail.
2599 * Else do nothing.
2600 * On failure, store an error object through @errp if non-null.
2602 void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp)
2604 if (key) {
2605 if (!bdrv_is_encrypted(bs)) {
2606 error_setg(errp, "Node '%s' is not encrypted",
2607 bdrv_get_device_or_node_name(bs));
2608 } else if (bdrv_set_key(bs, key) < 0) {
2609 error_setg(errp, QERR_INVALID_PASSWORD);
2611 } else {
2612 if (bdrv_key_required(bs)) {
2613 error_set(errp, ERROR_CLASS_DEVICE_ENCRYPTED,
2614 "'%s' (%s) is encrypted",
2615 bdrv_get_device_or_node_name(bs),
2616 bdrv_get_encrypted_filename(bs));
2621 const char *bdrv_get_format_name(BlockDriverState *bs)
2623 return bs->drv ? bs->drv->format_name : NULL;
2626 static int qsort_strcmp(const void *a, const void *b)
2628 return strcmp(a, b);
2631 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
2632 void *opaque)
2634 BlockDriver *drv;
2635 int count = 0;
2636 int i;
2637 const char **formats = NULL;
2639 QLIST_FOREACH(drv, &bdrv_drivers, list) {
2640 if (drv->format_name) {
2641 bool found = false;
2642 int i = count;
2643 while (formats && i && !found) {
2644 found = !strcmp(formats[--i], drv->format_name);
2647 if (!found) {
2648 formats = g_renew(const char *, formats, count + 1);
2649 formats[count++] = drv->format_name;
2654 qsort(formats, count, sizeof(formats[0]), qsort_strcmp);
2656 for (i = 0; i < count; i++) {
2657 it(opaque, formats[i]);
2660 g_free(formats);
2663 /* This function is to find a node in the bs graph */
2664 BlockDriverState *bdrv_find_node(const char *node_name)
2666 BlockDriverState *bs;
2668 assert(node_name);
2670 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
2671 if (!strcmp(node_name, bs->node_name)) {
2672 return bs;
2675 return NULL;
2678 /* Put this QMP function here so it can access the static graph_bdrv_states. */
2679 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp)
2681 BlockDeviceInfoList *list, *entry;
2682 BlockDriverState *bs;
2684 list = NULL;
2685 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
2686 BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, errp);
2687 if (!info) {
2688 qapi_free_BlockDeviceInfoList(list);
2689 return NULL;
2691 entry = g_malloc0(sizeof(*entry));
2692 entry->value = info;
2693 entry->next = list;
2694 list = entry;
2697 return list;
2700 BlockDriverState *bdrv_lookup_bs(const char *device,
2701 const char *node_name,
2702 Error **errp)
2704 BlockBackend *blk;
2705 BlockDriverState *bs;
2707 if (device) {
2708 blk = blk_by_name(device);
2710 if (blk) {
2711 bs = blk_bs(blk);
2712 if (!bs) {
2713 error_setg(errp, "Device '%s' has no medium", device);
2716 return bs;
2720 if (node_name) {
2721 bs = bdrv_find_node(node_name);
2723 if (bs) {
2724 return bs;
2728 error_setg(errp, "Cannot find device=%s nor node_name=%s",
2729 device ? device : "",
2730 node_name ? node_name : "");
2731 return NULL;
2734 /* If 'base' is in the same chain as 'top', return true. Otherwise,
2735 * return false. If either argument is NULL, return false. */
2736 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base)
2738 while (top && top != base) {
2739 top = backing_bs(top);
2742 return top != NULL;
2745 BlockDriverState *bdrv_next_node(BlockDriverState *bs)
2747 if (!bs) {
2748 return QTAILQ_FIRST(&graph_bdrv_states);
2750 return QTAILQ_NEXT(bs, node_list);
2753 const char *bdrv_get_node_name(const BlockDriverState *bs)
2755 return bs->node_name;
2758 const char *bdrv_get_parent_name(const BlockDriverState *bs)
2760 BdrvChild *c;
2761 const char *name;
2763 /* If multiple parents have a name, just pick the first one. */
2764 QLIST_FOREACH(c, &bs->parents, next_parent) {
2765 if (c->role->get_name) {
2766 name = c->role->get_name(c);
2767 if (name && *name) {
2768 return name;
2773 return NULL;
2776 /* TODO check what callers really want: bs->node_name or blk_name() */
2777 const char *bdrv_get_device_name(const BlockDriverState *bs)
2779 return bdrv_get_parent_name(bs) ?: "";
2782 /* This can be used to identify nodes that might not have a device
2783 * name associated. Since node and device names live in the same
2784 * namespace, the result is unambiguous. The exception is if both are
2785 * absent, then this returns an empty (non-null) string. */
2786 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs)
2788 return bdrv_get_parent_name(bs) ?: bs->node_name;
2791 int bdrv_get_flags(BlockDriverState *bs)
2793 return bs->open_flags;
2796 int bdrv_has_zero_init_1(BlockDriverState *bs)
2798 return 1;
2801 int bdrv_has_zero_init(BlockDriverState *bs)
2803 assert(bs->drv);
2805 /* If BS is a copy on write image, it is initialized to
2806 the contents of the base image, which may not be zeroes. */
2807 if (bs->backing) {
2808 return 0;
2810 if (bs->drv->bdrv_has_zero_init) {
2811 return bs->drv->bdrv_has_zero_init(bs);
2814 /* safe default */
2815 return 0;
2818 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs)
2820 BlockDriverInfo bdi;
2822 if (bs->backing) {
2823 return false;
2826 if (bdrv_get_info(bs, &bdi) == 0) {
2827 return bdi.unallocated_blocks_are_zero;
2830 return false;
2833 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
2835 BlockDriverInfo bdi;
2837 if (bs->backing || !(bs->open_flags & BDRV_O_UNMAP)) {
2838 return false;
2841 if (bdrv_get_info(bs, &bdi) == 0) {
2842 return bdi.can_write_zeroes_with_unmap;
2845 return false;
2848 const char *bdrv_get_encrypted_filename(BlockDriverState *bs)
2850 if (bs->backing && bs->backing->bs->encrypted)
2851 return bs->backing_file;
2852 else if (bs->encrypted)
2853 return bs->filename;
2854 else
2855 return NULL;
2858 void bdrv_get_backing_filename(BlockDriverState *bs,
2859 char *filename, int filename_size)
2861 pstrcpy(filename, filename_size, bs->backing_file);
2864 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
2866 BlockDriver *drv = bs->drv;
2867 if (!drv)
2868 return -ENOMEDIUM;
2869 if (!drv->bdrv_get_info)
2870 return -ENOTSUP;
2871 memset(bdi, 0, sizeof(*bdi));
2872 return drv->bdrv_get_info(bs, bdi);
2875 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs)
2877 BlockDriver *drv = bs->drv;
2878 if (drv && drv->bdrv_get_specific_info) {
2879 return drv->bdrv_get_specific_info(bs);
2881 return NULL;
2884 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event)
2886 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
2887 return;
2890 bs->drv->bdrv_debug_event(bs, event);
2893 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
2894 const char *tag)
2896 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) {
2897 bs = bs->file ? bs->file->bs : NULL;
2900 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) {
2901 return bs->drv->bdrv_debug_breakpoint(bs, event, tag);
2904 return -ENOTSUP;
2907 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag)
2909 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) {
2910 bs = bs->file ? bs->file->bs : NULL;
2913 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) {
2914 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag);
2917 return -ENOTSUP;
2920 int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
2922 while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) {
2923 bs = bs->file ? bs->file->bs : NULL;
2926 if (bs && bs->drv && bs->drv->bdrv_debug_resume) {
2927 return bs->drv->bdrv_debug_resume(bs, tag);
2930 return -ENOTSUP;
2933 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag)
2935 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) {
2936 bs = bs->file ? bs->file->bs : NULL;
2939 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) {
2940 return bs->drv->bdrv_debug_is_suspended(bs, tag);
2943 return false;
2946 int bdrv_is_snapshot(BlockDriverState *bs)
2948 return !!(bs->open_flags & BDRV_O_SNAPSHOT);
2951 /* backing_file can either be relative, or absolute, or a protocol. If it is
2952 * relative, it must be relative to the chain. So, passing in bs->filename
2953 * from a BDS as backing_file should not be done, as that may be relative to
2954 * the CWD rather than the chain. */
2955 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
2956 const char *backing_file)
2958 char *filename_full = NULL;
2959 char *backing_file_full = NULL;
2960 char *filename_tmp = NULL;
2961 int is_protocol = 0;
2962 BlockDriverState *curr_bs = NULL;
2963 BlockDriverState *retval = NULL;
2965 if (!bs || !bs->drv || !backing_file) {
2966 return NULL;
2969 filename_full = g_malloc(PATH_MAX);
2970 backing_file_full = g_malloc(PATH_MAX);
2971 filename_tmp = g_malloc(PATH_MAX);
2973 is_protocol = path_has_protocol(backing_file);
2975 for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) {
2977 /* If either of the filename paths is actually a protocol, then
2978 * compare unmodified paths; otherwise make paths relative */
2979 if (is_protocol || path_has_protocol(curr_bs->backing_file)) {
2980 if (strcmp(backing_file, curr_bs->backing_file) == 0) {
2981 retval = curr_bs->backing->bs;
2982 break;
2984 } else {
2985 /* If not an absolute filename path, make it relative to the current
2986 * image's filename path */
2987 path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
2988 backing_file);
2990 /* We are going to compare absolute pathnames */
2991 if (!realpath(filename_tmp, filename_full)) {
2992 continue;
2995 /* We need to make sure the backing filename we are comparing against
2996 * is relative to the current image filename (or absolute) */
2997 path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
2998 curr_bs->backing_file);
3000 if (!realpath(filename_tmp, backing_file_full)) {
3001 continue;
3004 if (strcmp(backing_file_full, filename_full) == 0) {
3005 retval = curr_bs->backing->bs;
3006 break;
3011 g_free(filename_full);
3012 g_free(backing_file_full);
3013 g_free(filename_tmp);
3014 return retval;
3017 int bdrv_get_backing_file_depth(BlockDriverState *bs)
3019 if (!bs->drv) {
3020 return 0;
3023 if (!bs->backing) {
3024 return 0;
3027 return 1 + bdrv_get_backing_file_depth(bs->backing->bs);
3030 void bdrv_init(void)
3032 module_call_init(MODULE_INIT_BLOCK);
3035 void bdrv_init_with_whitelist(void)
3037 use_bdrv_whitelist = 1;
3038 bdrv_init();
3041 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
3043 BdrvChild *child;
3044 Error *local_err = NULL;
3045 int ret;
3047 if (!bs->drv) {
3048 return;
3051 if (!(bs->open_flags & BDRV_O_INACTIVE)) {
3052 return;
3054 bs->open_flags &= ~BDRV_O_INACTIVE;
3056 if (bs->drv->bdrv_invalidate_cache) {
3057 bs->drv->bdrv_invalidate_cache(bs, &local_err);
3058 if (local_err) {
3059 bs->open_flags |= BDRV_O_INACTIVE;
3060 error_propagate(errp, local_err);
3061 return;
3065 QLIST_FOREACH(child, &bs->children, next) {
3066 bdrv_invalidate_cache(child->bs, &local_err);
3067 if (local_err) {
3068 bs->open_flags |= BDRV_O_INACTIVE;
3069 error_propagate(errp, local_err);
3070 return;
3074 ret = refresh_total_sectors(bs, bs->total_sectors);
3075 if (ret < 0) {
3076 bs->open_flags |= BDRV_O_INACTIVE;
3077 error_setg_errno(errp, -ret, "Could not refresh total sector count");
3078 return;
3082 void bdrv_invalidate_cache_all(Error **errp)
3084 BlockDriverState *bs;
3085 Error *local_err = NULL;
3086 BdrvNextIterator it;
3088 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3089 AioContext *aio_context = bdrv_get_aio_context(bs);
3091 aio_context_acquire(aio_context);
3092 bdrv_invalidate_cache(bs, &local_err);
3093 aio_context_release(aio_context);
3094 if (local_err) {
3095 error_propagate(errp, local_err);
3096 return;
3101 static int bdrv_inactivate_recurse(BlockDriverState *bs,
3102 bool setting_flag)
3104 BdrvChild *child;
3105 int ret;
3107 if (!setting_flag && bs->drv->bdrv_inactivate) {
3108 ret = bs->drv->bdrv_inactivate(bs);
3109 if (ret < 0) {
3110 return ret;
3114 QLIST_FOREACH(child, &bs->children, next) {
3115 ret = bdrv_inactivate_recurse(child->bs, setting_flag);
3116 if (ret < 0) {
3117 return ret;
3121 if (setting_flag) {
3122 bs->open_flags |= BDRV_O_INACTIVE;
3124 return 0;
3127 int bdrv_inactivate_all(void)
3129 BlockDriverState *bs = NULL;
3130 BdrvNextIterator it;
3131 int ret = 0;
3132 int pass;
3134 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3135 aio_context_acquire(bdrv_get_aio_context(bs));
3138 /* We do two passes of inactivation. The first pass calls to drivers'
3139 * .bdrv_inactivate callbacks recursively so all cache is flushed to disk;
3140 * the second pass sets the BDRV_O_INACTIVE flag so that no further write
3141 * is allowed. */
3142 for (pass = 0; pass < 2; pass++) {
3143 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3144 ret = bdrv_inactivate_recurse(bs, pass);
3145 if (ret < 0) {
3146 goto out;
3151 out:
3152 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3153 aio_context_release(bdrv_get_aio_context(bs));
3156 return ret;
3159 /**************************************************************/
3160 /* removable device support */
3163 * Return TRUE if the media is present
3165 bool bdrv_is_inserted(BlockDriverState *bs)
3167 BlockDriver *drv = bs->drv;
3168 BdrvChild *child;
3170 if (!drv) {
3171 return false;
3173 if (drv->bdrv_is_inserted) {
3174 return drv->bdrv_is_inserted(bs);
3176 QLIST_FOREACH(child, &bs->children, next) {
3177 if (!bdrv_is_inserted(child->bs)) {
3178 return false;
3181 return true;
3185 * Return whether the media changed since the last call to this
3186 * function, or -ENOTSUP if we don't know. Most drivers don't know.
3188 int bdrv_media_changed(BlockDriverState *bs)
3190 BlockDriver *drv = bs->drv;
3192 if (drv && drv->bdrv_media_changed) {
3193 return drv->bdrv_media_changed(bs);
3195 return -ENOTSUP;
3199 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
3201 void bdrv_eject(BlockDriverState *bs, bool eject_flag)
3203 BlockDriver *drv = bs->drv;
3204 const char *device_name;
3206 if (drv && drv->bdrv_eject) {
3207 drv->bdrv_eject(bs, eject_flag);
3210 device_name = bdrv_get_device_name(bs);
3211 if (device_name[0] != '\0') {
3212 qapi_event_send_device_tray_moved(device_name,
3213 eject_flag, &error_abort);
3218 * Lock or unlock the media (if it is locked, the user won't be able
3219 * to eject it manually).
3221 void bdrv_lock_medium(BlockDriverState *bs, bool locked)
3223 BlockDriver *drv = bs->drv;
3225 trace_bdrv_lock_medium(bs, locked);
3227 if (drv && drv->bdrv_lock_medium) {
3228 drv->bdrv_lock_medium(bs, locked);
3232 /* Get a reference to bs */
3233 void bdrv_ref(BlockDriverState *bs)
3235 bs->refcnt++;
3238 /* Release a previously grabbed reference to bs.
3239 * If after releasing, reference count is zero, the BlockDriverState is
3240 * deleted. */
3241 void bdrv_unref(BlockDriverState *bs)
3243 if (!bs) {
3244 return;
3246 assert(bs->refcnt > 0);
3247 if (--bs->refcnt == 0) {
3248 bdrv_delete(bs);
3252 struct BdrvOpBlocker {
3253 Error *reason;
3254 QLIST_ENTRY(BdrvOpBlocker) list;
3257 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp)
3259 BdrvOpBlocker *blocker;
3260 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
3261 if (!QLIST_EMPTY(&bs->op_blockers[op])) {
3262 blocker = QLIST_FIRST(&bs->op_blockers[op]);
3263 if (errp) {
3264 *errp = error_copy(blocker->reason);
3265 error_prepend(errp, "Node '%s' is busy: ",
3266 bdrv_get_device_or_node_name(bs));
3268 return true;
3270 return false;
3273 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason)
3275 BdrvOpBlocker *blocker;
3276 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
3278 blocker = g_new0(BdrvOpBlocker, 1);
3279 blocker->reason = reason;
3280 QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list);
3283 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason)
3285 BdrvOpBlocker *blocker, *next;
3286 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
3287 QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) {
3288 if (blocker->reason == reason) {
3289 QLIST_REMOVE(blocker, list);
3290 g_free(blocker);
3295 void bdrv_op_block_all(BlockDriverState *bs, Error *reason)
3297 int i;
3298 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
3299 bdrv_op_block(bs, i, reason);
3303 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason)
3305 int i;
3306 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
3307 bdrv_op_unblock(bs, i, reason);
3311 bool bdrv_op_blocker_is_empty(BlockDriverState *bs)
3313 int i;
3315 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
3316 if (!QLIST_EMPTY(&bs->op_blockers[i])) {
3317 return false;
3320 return true;
3323 void bdrv_img_create(const char *filename, const char *fmt,
3324 const char *base_filename, const char *base_fmt,
3325 char *options, uint64_t img_size, int flags,
3326 Error **errp, bool quiet)
3328 QemuOptsList *create_opts = NULL;
3329 QemuOpts *opts = NULL;
3330 const char *backing_fmt, *backing_file;
3331 int64_t size;
3332 BlockDriver *drv, *proto_drv;
3333 Error *local_err = NULL;
3334 int ret = 0;
3336 /* Find driver and parse its options */
3337 drv = bdrv_find_format(fmt);
3338 if (!drv) {
3339 error_setg(errp, "Unknown file format '%s'", fmt);
3340 return;
3343 proto_drv = bdrv_find_protocol(filename, true, errp);
3344 if (!proto_drv) {
3345 return;
3348 if (!drv->create_opts) {
3349 error_setg(errp, "Format driver '%s' does not support image creation",
3350 drv->format_name);
3351 return;
3354 if (!proto_drv->create_opts) {
3355 error_setg(errp, "Protocol driver '%s' does not support image creation",
3356 proto_drv->format_name);
3357 return;
3360 create_opts = qemu_opts_append(create_opts, drv->create_opts);
3361 create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
3363 /* Create parameter list with default values */
3364 opts = qemu_opts_create(create_opts, NULL, 0, &error_abort);
3365 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, img_size, &error_abort);
3367 /* Parse -o options */
3368 if (options) {
3369 qemu_opts_do_parse(opts, options, NULL, &local_err);
3370 if (local_err) {
3371 error_report_err(local_err);
3372 local_err = NULL;
3373 error_setg(errp, "Invalid options for file format '%s'", fmt);
3374 goto out;
3378 if (base_filename) {
3379 qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename, &local_err);
3380 if (local_err) {
3381 error_setg(errp, "Backing file not supported for file format '%s'",
3382 fmt);
3383 goto out;
3387 if (base_fmt) {
3388 qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt, &local_err);
3389 if (local_err) {
3390 error_setg(errp, "Backing file format not supported for file "
3391 "format '%s'", fmt);
3392 goto out;
3396 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
3397 if (backing_file) {
3398 if (!strcmp(filename, backing_file)) {
3399 error_setg(errp, "Error: Trying to create an image with the "
3400 "same filename as the backing file");
3401 goto out;
3405 backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
3407 // The size for the image must always be specified, with one exception:
3408 // If we are using a backing file, we can obtain the size from there
3409 size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
3410 if (size == -1) {
3411 if (backing_file) {
3412 BlockDriverState *bs;
3413 char *full_backing = g_new0(char, PATH_MAX);
3414 int64_t size;
3415 int back_flags;
3416 QDict *backing_options = NULL;
3418 bdrv_get_full_backing_filename_from_filename(filename, backing_file,
3419 full_backing, PATH_MAX,
3420 &local_err);
3421 if (local_err) {
3422 g_free(full_backing);
3423 goto out;
3426 /* backing files always opened read-only */
3427 back_flags = flags;
3428 back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
3430 if (backing_fmt) {
3431 backing_options = qdict_new();
3432 qdict_put(backing_options, "driver",
3433 qstring_from_str(backing_fmt));
3436 bs = bdrv_open(full_backing, NULL, backing_options, back_flags,
3437 &local_err);
3438 g_free(full_backing);
3439 if (!bs) {
3440 goto out;
3442 size = bdrv_getlength(bs);
3443 if (size < 0) {
3444 error_setg_errno(errp, -size, "Could not get size of '%s'",
3445 backing_file);
3446 bdrv_unref(bs);
3447 goto out;
3450 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort);
3452 bdrv_unref(bs);
3453 } else {
3454 error_setg(errp, "Image creation needs a size parameter");
3455 goto out;
3459 if (!quiet) {
3460 printf("Formatting '%s', fmt=%s ", filename, fmt);
3461 qemu_opts_print(opts, " ");
3462 puts("");
3465 ret = bdrv_create(drv, filename, opts, &local_err);
3467 if (ret == -EFBIG) {
3468 /* This is generally a better message than whatever the driver would
3469 * deliver (especially because of the cluster_size_hint), since that
3470 * is most probably not much different from "image too large". */
3471 const char *cluster_size_hint = "";
3472 if (qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 0)) {
3473 cluster_size_hint = " (try using a larger cluster size)";
3475 error_setg(errp, "The image size is too large for file format '%s'"
3476 "%s", fmt, cluster_size_hint);
3477 error_free(local_err);
3478 local_err = NULL;
3481 out:
3482 qemu_opts_del(opts);
3483 qemu_opts_free(create_opts);
3484 error_propagate(errp, local_err);
3487 AioContext *bdrv_get_aio_context(BlockDriverState *bs)
3489 return bs->aio_context;
3492 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban)
3494 QLIST_REMOVE(ban, list);
3495 g_free(ban);
3498 void bdrv_detach_aio_context(BlockDriverState *bs)
3500 BdrvAioNotifier *baf, *baf_tmp;
3501 BdrvChild *child;
3503 if (!bs->drv) {
3504 return;
3507 assert(!bs->walking_aio_notifiers);
3508 bs->walking_aio_notifiers = true;
3509 QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) {
3510 if (baf->deleted) {
3511 bdrv_do_remove_aio_context_notifier(baf);
3512 } else {
3513 baf->detach_aio_context(baf->opaque);
3516 /* Never mind iterating again to check for ->deleted. bdrv_close() will
3517 * remove remaining aio notifiers if we aren't called again.
3519 bs->walking_aio_notifiers = false;
3521 if (bs->drv->bdrv_detach_aio_context) {
3522 bs->drv->bdrv_detach_aio_context(bs);
3524 QLIST_FOREACH(child, &bs->children, next) {
3525 bdrv_detach_aio_context(child->bs);
3528 bs->aio_context = NULL;
3531 void bdrv_attach_aio_context(BlockDriverState *bs,
3532 AioContext *new_context)
3534 BdrvAioNotifier *ban, *ban_tmp;
3535 BdrvChild *child;
3537 if (!bs->drv) {
3538 return;
3541 bs->aio_context = new_context;
3543 QLIST_FOREACH(child, &bs->children, next) {
3544 bdrv_attach_aio_context(child->bs, new_context);
3546 if (bs->drv->bdrv_attach_aio_context) {
3547 bs->drv->bdrv_attach_aio_context(bs, new_context);
3550 assert(!bs->walking_aio_notifiers);
3551 bs->walking_aio_notifiers = true;
3552 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_tmp) {
3553 if (ban->deleted) {
3554 bdrv_do_remove_aio_context_notifier(ban);
3555 } else {
3556 ban->attached_aio_context(new_context, ban->opaque);
3559 bs->walking_aio_notifiers = false;
3562 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
3564 bdrv_drain(bs); /* ensure there are no in-flight requests */
3566 bdrv_detach_aio_context(bs);
3568 /* This function executes in the old AioContext so acquire the new one in
3569 * case it runs in a different thread.
3571 aio_context_acquire(new_context);
3572 bdrv_attach_aio_context(bs, new_context);
3573 aio_context_release(new_context);
3576 void bdrv_add_aio_context_notifier(BlockDriverState *bs,
3577 void (*attached_aio_context)(AioContext *new_context, void *opaque),
3578 void (*detach_aio_context)(void *opaque), void *opaque)
3580 BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1);
3581 *ban = (BdrvAioNotifier){
3582 .attached_aio_context = attached_aio_context,
3583 .detach_aio_context = detach_aio_context,
3584 .opaque = opaque
3587 QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list);
3590 void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
3591 void (*attached_aio_context)(AioContext *,
3592 void *),
3593 void (*detach_aio_context)(void *),
3594 void *opaque)
3596 BdrvAioNotifier *ban, *ban_next;
3598 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
3599 if (ban->attached_aio_context == attached_aio_context &&
3600 ban->detach_aio_context == detach_aio_context &&
3601 ban->opaque == opaque &&
3602 ban->deleted == false)
3604 if (bs->walking_aio_notifiers) {
3605 ban->deleted = true;
3606 } else {
3607 bdrv_do_remove_aio_context_notifier(ban);
3609 return;
3613 abort();
3616 int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts,
3617 BlockDriverAmendStatusCB *status_cb, void *cb_opaque)
3619 if (!bs->drv->bdrv_amend_options) {
3620 return -ENOTSUP;
3622 return bs->drv->bdrv_amend_options(bs, opts, status_cb, cb_opaque);
3625 /* This function will be called by the bdrv_recurse_is_first_non_filter method
3626 * of block filter and by bdrv_is_first_non_filter.
3627 * It is used to test if the given bs is the candidate or recurse more in the
3628 * node graph.
3630 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
3631 BlockDriverState *candidate)
3633 /* return false if basic checks fails */
3634 if (!bs || !bs->drv) {
3635 return false;
3638 /* the code reached a non block filter driver -> check if the bs is
3639 * the same as the candidate. It's the recursion termination condition.
3641 if (!bs->drv->is_filter) {
3642 return bs == candidate;
3644 /* Down this path the driver is a block filter driver */
3646 /* If the block filter recursion method is defined use it to recurse down
3647 * the node graph.
3649 if (bs->drv->bdrv_recurse_is_first_non_filter) {
3650 return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate);
3653 /* the driver is a block filter but don't allow to recurse -> return false
3655 return false;
3658 /* This function checks if the candidate is the first non filter bs down it's
3659 * bs chain. Since we don't have pointers to parents it explore all bs chains
3660 * from the top. Some filters can choose not to pass down the recursion.
3662 bool bdrv_is_first_non_filter(BlockDriverState *candidate)
3664 BlockDriverState *bs;
3665 BdrvNextIterator it;
3667 /* walk down the bs forest recursively */
3668 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3669 bool perm;
3671 /* try to recurse in this top level bs */
3672 perm = bdrv_recurse_is_first_non_filter(bs, candidate);
3674 /* candidate is the first non filter */
3675 if (perm) {
3676 return true;
3680 return false;
3683 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
3684 const char *node_name, Error **errp)
3686 BlockDriverState *to_replace_bs = bdrv_find_node(node_name);
3687 AioContext *aio_context;
3689 if (!to_replace_bs) {
3690 error_setg(errp, "Node name '%s' not found", node_name);
3691 return NULL;
3694 aio_context = bdrv_get_aio_context(to_replace_bs);
3695 aio_context_acquire(aio_context);
3697 if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) {
3698 to_replace_bs = NULL;
3699 goto out;
3702 /* We don't want arbitrary node of the BDS chain to be replaced only the top
3703 * most non filter in order to prevent data corruption.
3704 * Another benefit is that this tests exclude backing files which are
3705 * blocked by the backing blockers.
3707 if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) {
3708 error_setg(errp, "Only top most non filter can be replaced");
3709 to_replace_bs = NULL;
3710 goto out;
3713 out:
3714 aio_context_release(aio_context);
3715 return to_replace_bs;
3718 static bool append_open_options(QDict *d, BlockDriverState *bs)
3720 const QDictEntry *entry;
3721 QemuOptDesc *desc;
3722 BdrvChild *child;
3723 bool found_any = false;
3724 const char *p;
3726 for (entry = qdict_first(bs->options); entry;
3727 entry = qdict_next(bs->options, entry))
3729 /* Exclude options for children */
3730 QLIST_FOREACH(child, &bs->children, next) {
3731 if (strstart(qdict_entry_key(entry), child->name, &p)
3732 && (!*p || *p == '.'))
3734 break;
3737 if (child) {
3738 continue;
3741 /* And exclude all non-driver-specific options */
3742 for (desc = bdrv_runtime_opts.desc; desc->name; desc++) {
3743 if (!strcmp(qdict_entry_key(entry), desc->name)) {
3744 break;
3747 if (desc->name) {
3748 continue;
3751 qobject_incref(qdict_entry_value(entry));
3752 qdict_put_obj(d, qdict_entry_key(entry), qdict_entry_value(entry));
3753 found_any = true;
3756 return found_any;
3759 /* Updates the following BDS fields:
3760 * - exact_filename: A filename which may be used for opening a block device
3761 * which (mostly) equals the given BDS (even without any
3762 * other options; so reading and writing must return the same
3763 * results, but caching etc. may be different)
3764 * - full_open_options: Options which, when given when opening a block device
3765 * (without a filename), result in a BDS (mostly)
3766 * equalling the given one
3767 * - filename: If exact_filename is set, it is copied here. Otherwise,
3768 * full_open_options is converted to a JSON object, prefixed with
3769 * "json:" (for use through the JSON pseudo protocol) and put here.
3771 void bdrv_refresh_filename(BlockDriverState *bs)
3773 BlockDriver *drv = bs->drv;
3774 QDict *opts;
3776 if (!drv) {
3777 return;
3780 /* This BDS's file name will most probably depend on its file's name, so
3781 * refresh that first */
3782 if (bs->file) {
3783 bdrv_refresh_filename(bs->file->bs);
3786 if (drv->bdrv_refresh_filename) {
3787 /* Obsolete information is of no use here, so drop the old file name
3788 * information before refreshing it */
3789 bs->exact_filename[0] = '\0';
3790 if (bs->full_open_options) {
3791 QDECREF(bs->full_open_options);
3792 bs->full_open_options = NULL;
3795 opts = qdict_new();
3796 append_open_options(opts, bs);
3797 drv->bdrv_refresh_filename(bs, opts);
3798 QDECREF(opts);
3799 } else if (bs->file) {
3800 /* Try to reconstruct valid information from the underlying file */
3801 bool has_open_options;
3803 bs->exact_filename[0] = '\0';
3804 if (bs->full_open_options) {
3805 QDECREF(bs->full_open_options);
3806 bs->full_open_options = NULL;
3809 opts = qdict_new();
3810 has_open_options = append_open_options(opts, bs);
3812 /* If no specific options have been given for this BDS, the filename of
3813 * the underlying file should suffice for this one as well */
3814 if (bs->file->bs->exact_filename[0] && !has_open_options) {
3815 strcpy(bs->exact_filename, bs->file->bs->exact_filename);
3817 /* Reconstructing the full options QDict is simple for most format block
3818 * drivers, as long as the full options are known for the underlying
3819 * file BDS. The full options QDict of that file BDS should somehow
3820 * contain a representation of the filename, therefore the following
3821 * suffices without querying the (exact_)filename of this BDS. */
3822 if (bs->file->bs->full_open_options) {
3823 qdict_put_obj(opts, "driver",
3824 QOBJECT(qstring_from_str(drv->format_name)));
3825 QINCREF(bs->file->bs->full_open_options);
3826 qdict_put_obj(opts, "file",
3827 QOBJECT(bs->file->bs->full_open_options));
3829 bs->full_open_options = opts;
3830 } else {
3831 QDECREF(opts);
3833 } else if (!bs->full_open_options && qdict_size(bs->options)) {
3834 /* There is no underlying file BDS (at least referenced by BDS.file),
3835 * so the full options QDict should be equal to the options given
3836 * specifically for this block device when it was opened (plus the
3837 * driver specification).
3838 * Because those options don't change, there is no need to update
3839 * full_open_options when it's already set. */
3841 opts = qdict_new();
3842 append_open_options(opts, bs);
3843 qdict_put_obj(opts, "driver",
3844 QOBJECT(qstring_from_str(drv->format_name)));
3846 if (bs->exact_filename[0]) {
3847 /* This may not work for all block protocol drivers (some may
3848 * require this filename to be parsed), but we have to find some
3849 * default solution here, so just include it. If some block driver
3850 * does not support pure options without any filename at all or
3851 * needs some special format of the options QDict, it needs to
3852 * implement the driver-specific bdrv_refresh_filename() function.
3854 qdict_put_obj(opts, "filename",
3855 QOBJECT(qstring_from_str(bs->exact_filename)));
3858 bs->full_open_options = opts;
3861 if (bs->exact_filename[0]) {
3862 pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename);
3863 } else if (bs->full_open_options) {
3864 QString *json = qobject_to_json(QOBJECT(bs->full_open_options));
3865 snprintf(bs->filename, sizeof(bs->filename), "json:%s",
3866 qstring_get_str(json));
3867 QDECREF(json);
3872 * Hot add/remove a BDS's child. So the user can take a child offline when
3873 * it is broken and take a new child online
3875 void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs,
3876 Error **errp)
3879 if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) {
3880 error_setg(errp, "The node %s does not support adding a child",
3881 bdrv_get_device_or_node_name(parent_bs));
3882 return;
3885 if (!QLIST_EMPTY(&child_bs->parents)) {
3886 error_setg(errp, "The node %s already has a parent",
3887 child_bs->node_name);
3888 return;
3891 parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp);
3894 void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp)
3896 BdrvChild *tmp;
3898 if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) {
3899 error_setg(errp, "The node %s does not support removing a child",
3900 bdrv_get_device_or_node_name(parent_bs));
3901 return;
3904 QLIST_FOREACH(tmp, &parent_bs->children, next) {
3905 if (tmp == child) {
3906 break;
3910 if (!tmp) {
3911 error_setg(errp, "The node %s does not have a child named %s",
3912 bdrv_get_device_or_node_name(parent_bs),
3913 bdrv_get_device_or_node_name(child->bs));
3914 return;
3917 parent_bs->drv->bdrv_del_child(parent_bs, child, errp);