arm: spelling fix: mismatch
[qemu/ar7.git] / block.c
blob101f8c628f06cdcf174785c913e0f3e1ae7dfedc
1 /*
2 * QEMU System Emulator block driver
4 * Copyright (c) 2003 Fabrice Bellard
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
24 #include "qemu/osdep.h"
25 #include "trace.h"
26 #include "block/block_int.h"
27 #include "block/blockjob.h"
28 #include "block/nbd.h"
29 #include "qemu/error-report.h"
30 #include "qemu/module.h"
31 #include "qapi/qmp/qerror.h"
32 #include "qapi/qmp/qbool.h"
33 #include "qapi/qmp/qjson.h"
34 #include "sysemu/block-backend.h"
35 #include "sysemu/sysemu.h"
36 #include "qemu/notify.h"
37 #include "qemu/coroutine.h"
38 #include "block/qapi.h"
39 #include "qmp-commands.h"
40 #include "qemu/timer.h"
41 #include "qapi-event.h"
42 #include "qemu/cutils.h"
43 #include "qemu/id.h"
45 #ifdef CONFIG_BSD
46 #include <sys/ioctl.h>
47 #include <sys/queue.h>
48 #ifndef __DragonFly__
49 #include <sys/disk.h>
50 #endif
51 #endif
53 #ifdef _WIN32
54 #include <windows.h>
55 #endif
57 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
59 static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states =
60 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states);
62 static QTAILQ_HEAD(, BlockDriverState) all_bdrv_states =
63 QTAILQ_HEAD_INITIALIZER(all_bdrv_states);
65 static QLIST_HEAD(, BlockDriver) bdrv_drivers =
66 QLIST_HEAD_INITIALIZER(bdrv_drivers);
68 static BlockDriverState *bdrv_open_inherit(const char *filename,
69 const char *reference,
70 QDict *options, int flags,
71 BlockDriverState *parent,
72 const BdrvChildRole *child_role,
73 Error **errp);
75 /* If non-zero, use only whitelisted block drivers */
76 static int use_bdrv_whitelist;
78 #ifdef _WIN32
79 static int is_windows_drive_prefix(const char *filename)
81 return (((filename[0] >= 'a' && filename[0] <= 'z') ||
82 (filename[0] >= 'A' && filename[0] <= 'Z')) &&
83 filename[1] == ':');
86 int is_windows_drive(const char *filename)
88 if (is_windows_drive_prefix(filename) &&
89 filename[2] == '\0')
90 return 1;
91 if (strstart(filename, "\\\\.\\", NULL) ||
92 strstart(filename, "//./", NULL))
93 return 1;
94 return 0;
96 #endif
98 size_t bdrv_opt_mem_align(BlockDriverState *bs)
100 if (!bs || !bs->drv) {
101 /* page size or 4k (hdd sector size) should be on the safe side */
102 return MAX(4096, getpagesize());
105 return bs->bl.opt_mem_alignment;
108 size_t bdrv_min_mem_align(BlockDriverState *bs)
110 if (!bs || !bs->drv) {
111 /* page size or 4k (hdd sector size) should be on the safe side */
112 return MAX(4096, getpagesize());
115 return bs->bl.min_mem_alignment;
118 /* check if the path starts with "<protocol>:" */
119 int path_has_protocol(const char *path)
121 const char *p;
123 #ifdef _WIN32
124 if (is_windows_drive(path) ||
125 is_windows_drive_prefix(path)) {
126 return 0;
128 p = path + strcspn(path, ":/\\");
129 #else
130 p = path + strcspn(path, ":/");
131 #endif
133 return *p == ':';
136 int path_is_absolute(const char *path)
138 #ifdef _WIN32
139 /* specific case for names like: "\\.\d:" */
140 if (is_windows_drive(path) || is_windows_drive_prefix(path)) {
141 return 1;
143 return (*path == '/' || *path == '\\');
144 #else
145 return (*path == '/');
146 #endif
149 /* if filename is absolute, just copy it to dest. Otherwise, build a
150 path to it by considering it is relative to base_path. URL are
151 supported. */
152 void path_combine(char *dest, int dest_size,
153 const char *base_path,
154 const char *filename)
156 const char *p, *p1;
157 int len;
159 if (dest_size <= 0)
160 return;
161 if (path_is_absolute(filename)) {
162 pstrcpy(dest, dest_size, filename);
163 } else {
164 p = strchr(base_path, ':');
165 if (p)
166 p++;
167 else
168 p = base_path;
169 p1 = strrchr(base_path, '/');
170 #ifdef _WIN32
172 const char *p2;
173 p2 = strrchr(base_path, '\\');
174 if (!p1 || p2 > p1)
175 p1 = p2;
177 #endif
178 if (p1)
179 p1++;
180 else
181 p1 = base_path;
182 if (p1 > p)
183 p = p1;
184 len = p - base_path;
185 if (len > dest_size - 1)
186 len = dest_size - 1;
187 memcpy(dest, base_path, len);
188 dest[len] = '\0';
189 pstrcat(dest, dest_size, filename);
193 void bdrv_get_full_backing_filename_from_filename(const char *backed,
194 const char *backing,
195 char *dest, size_t sz,
196 Error **errp)
198 if (backing[0] == '\0' || path_has_protocol(backing) ||
199 path_is_absolute(backing))
201 pstrcpy(dest, sz, backing);
202 } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) {
203 error_setg(errp, "Cannot use relative backing file names for '%s'",
204 backed);
205 } else {
206 path_combine(dest, sz, backed, backing);
210 void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz,
211 Error **errp)
213 char *backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename;
215 bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file,
216 dest, sz, errp);
219 void bdrv_register(BlockDriver *bdrv)
221 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list);
224 BlockDriverState *bdrv_new(void)
226 BlockDriverState *bs;
227 int i;
229 bs = g_new0(BlockDriverState, 1);
230 QLIST_INIT(&bs->dirty_bitmaps);
231 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
232 QLIST_INIT(&bs->op_blockers[i]);
234 notifier_with_return_list_init(&bs->before_write_notifiers);
235 bs->refcnt = 1;
236 bs->aio_context = qemu_get_aio_context();
238 qemu_co_queue_init(&bs->flush_queue);
240 QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list);
242 return bs;
245 BlockDriver *bdrv_find_format(const char *format_name)
247 BlockDriver *drv1;
248 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
249 if (!strcmp(drv1->format_name, format_name)) {
250 return drv1;
253 return NULL;
256 static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
258 static const char *whitelist_rw[] = {
259 CONFIG_BDRV_RW_WHITELIST
261 static const char *whitelist_ro[] = {
262 CONFIG_BDRV_RO_WHITELIST
264 const char **p;
266 if (!whitelist_rw[0] && !whitelist_ro[0]) {
267 return 1; /* no whitelist, anything goes */
270 for (p = whitelist_rw; *p; p++) {
271 if (!strcmp(drv->format_name, *p)) {
272 return 1;
275 if (read_only) {
276 for (p = whitelist_ro; *p; p++) {
277 if (!strcmp(drv->format_name, *p)) {
278 return 1;
282 return 0;
285 bool bdrv_uses_whitelist(void)
287 return use_bdrv_whitelist;
290 typedef struct CreateCo {
291 BlockDriver *drv;
292 char *filename;
293 QemuOpts *opts;
294 int ret;
295 Error *err;
296 } CreateCo;
298 static void coroutine_fn bdrv_create_co_entry(void *opaque)
300 Error *local_err = NULL;
301 int ret;
303 CreateCo *cco = opaque;
304 assert(cco->drv);
306 ret = cco->drv->bdrv_create(cco->filename, cco->opts, &local_err);
307 error_propagate(&cco->err, local_err);
308 cco->ret = ret;
311 int bdrv_create(BlockDriver *drv, const char* filename,
312 QemuOpts *opts, Error **errp)
314 int ret;
316 Coroutine *co;
317 CreateCo cco = {
318 .drv = drv,
319 .filename = g_strdup(filename),
320 .opts = opts,
321 .ret = NOT_DONE,
322 .err = NULL,
325 if (!drv->bdrv_create) {
326 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name);
327 ret = -ENOTSUP;
328 goto out;
331 if (qemu_in_coroutine()) {
332 /* Fast-path if already in coroutine context */
333 bdrv_create_co_entry(&cco);
334 } else {
335 co = qemu_coroutine_create(bdrv_create_co_entry, &cco);
336 qemu_coroutine_enter(co);
337 while (cco.ret == NOT_DONE) {
338 aio_poll(qemu_get_aio_context(), true);
342 ret = cco.ret;
343 if (ret < 0) {
344 if (cco.err) {
345 error_propagate(errp, cco.err);
346 } else {
347 error_setg_errno(errp, -ret, "Could not create image");
351 out:
352 g_free(cco.filename);
353 return ret;
356 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
358 BlockDriver *drv;
359 Error *local_err = NULL;
360 int ret;
362 drv = bdrv_find_protocol(filename, true, errp);
363 if (drv == NULL) {
364 return -ENOENT;
367 ret = bdrv_create(drv, filename, opts, &local_err);
368 error_propagate(errp, local_err);
369 return ret;
373 * Try to get @bs's logical and physical block size.
374 * On success, store them in @bsz struct and return 0.
375 * On failure return -errno.
376 * @bs must not be empty.
378 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
380 BlockDriver *drv = bs->drv;
382 if (drv && drv->bdrv_probe_blocksizes) {
383 return drv->bdrv_probe_blocksizes(bs, bsz);
386 return -ENOTSUP;
390 * Try to get @bs's geometry (cyls, heads, sectors).
391 * On success, store them in @geo struct and return 0.
392 * On failure return -errno.
393 * @bs must not be empty.
395 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
397 BlockDriver *drv = bs->drv;
399 if (drv && drv->bdrv_probe_geometry) {
400 return drv->bdrv_probe_geometry(bs, geo);
403 return -ENOTSUP;
407 * Create a uniquely-named empty temporary file.
408 * Return 0 upon success, otherwise a negative errno value.
410 int get_tmp_filename(char *filename, int size)
412 #ifdef _WIN32
413 char temp_dir[MAX_PATH];
414 /* GetTempFileName requires that its output buffer (4th param)
415 have length MAX_PATH or greater. */
416 assert(size >= MAX_PATH);
417 return (GetTempPath(MAX_PATH, temp_dir)
418 && GetTempFileName(temp_dir, "qem", 0, filename)
419 ? 0 : -GetLastError());
420 #else
421 int fd;
422 const char *tmpdir;
423 tmpdir = getenv("TMPDIR");
424 if (!tmpdir) {
425 tmpdir = "/var/tmp";
427 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) {
428 return -EOVERFLOW;
430 fd = mkstemp(filename);
431 if (fd < 0) {
432 return -errno;
434 if (close(fd) != 0) {
435 unlink(filename);
436 return -errno;
438 return 0;
439 #endif
443 * Detect host devices. By convention, /dev/cdrom[N] is always
444 * recognized as a host CDROM.
446 static BlockDriver *find_hdev_driver(const char *filename)
448 int score_max = 0, score;
449 BlockDriver *drv = NULL, *d;
451 QLIST_FOREACH(d, &bdrv_drivers, list) {
452 if (d->bdrv_probe_device) {
453 score = d->bdrv_probe_device(filename);
454 if (score > score_max) {
455 score_max = score;
456 drv = d;
461 return drv;
464 BlockDriver *bdrv_find_protocol(const char *filename,
465 bool allow_protocol_prefix,
466 Error **errp)
468 BlockDriver *drv1;
469 char protocol[128];
470 int len;
471 const char *p;
473 /* TODO Drivers without bdrv_file_open must be specified explicitly */
476 * XXX(hch): we really should not let host device detection
477 * override an explicit protocol specification, but moving this
478 * later breaks access to device names with colons in them.
479 * Thanks to the brain-dead persistent naming schemes on udev-
480 * based Linux systems those actually are quite common.
482 drv1 = find_hdev_driver(filename);
483 if (drv1) {
484 return drv1;
487 if (!path_has_protocol(filename) || !allow_protocol_prefix) {
488 return &bdrv_file;
491 p = strchr(filename, ':');
492 assert(p != NULL);
493 len = p - filename;
494 if (len > sizeof(protocol) - 1)
495 len = sizeof(protocol) - 1;
496 memcpy(protocol, filename, len);
497 protocol[len] = '\0';
498 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
499 if (drv1->protocol_name &&
500 !strcmp(drv1->protocol_name, protocol)) {
501 return drv1;
505 error_setg(errp, "Unknown protocol '%s'", protocol);
506 return NULL;
510 * Guess image format by probing its contents.
511 * This is not a good idea when your image is raw (CVE-2008-2004), but
512 * we do it anyway for backward compatibility.
514 * @buf contains the image's first @buf_size bytes.
515 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
516 * but can be smaller if the image file is smaller)
517 * @filename is its filename.
519 * For all block drivers, call the bdrv_probe() method to get its
520 * probing score.
521 * Return the first block driver with the highest probing score.
523 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
524 const char *filename)
526 int score_max = 0, score;
527 BlockDriver *drv = NULL, *d;
529 QLIST_FOREACH(d, &bdrv_drivers, list) {
530 if (d->bdrv_probe) {
531 score = d->bdrv_probe(buf, buf_size, filename);
532 if (score > score_max) {
533 score_max = score;
534 drv = d;
539 return drv;
542 static int find_image_format(BdrvChild *file, const char *filename,
543 BlockDriver **pdrv, Error **errp)
545 BlockDriverState *bs = file->bs;
546 BlockDriver *drv;
547 uint8_t buf[BLOCK_PROBE_BUF_SIZE];
548 int ret = 0;
550 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
551 if (bdrv_is_sg(bs) || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) {
552 *pdrv = &bdrv_raw;
553 return ret;
556 ret = bdrv_pread(file, 0, buf, sizeof(buf));
557 if (ret < 0) {
558 error_setg_errno(errp, -ret, "Could not read image for determining its "
559 "format");
560 *pdrv = NULL;
561 return ret;
564 drv = bdrv_probe_all(buf, ret, filename);
565 if (!drv) {
566 error_setg(errp, "Could not determine image format: No compatible "
567 "driver found");
568 ret = -ENOENT;
570 *pdrv = drv;
571 return ret;
575 * Set the current 'total_sectors' value
576 * Return 0 on success, -errno on error.
578 static int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
580 BlockDriver *drv = bs->drv;
582 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
583 if (bdrv_is_sg(bs))
584 return 0;
586 /* query actual device if possible, otherwise just trust the hint */
587 if (drv->bdrv_getlength) {
588 int64_t length = drv->bdrv_getlength(bs);
589 if (length < 0) {
590 return length;
592 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE);
595 bs->total_sectors = hint;
596 return 0;
600 * Combines a QDict of new block driver @options with any missing options taken
601 * from @old_options, so that leaving out an option defaults to its old value.
603 static void bdrv_join_options(BlockDriverState *bs, QDict *options,
604 QDict *old_options)
606 if (bs->drv && bs->drv->bdrv_join_options) {
607 bs->drv->bdrv_join_options(options, old_options);
608 } else {
609 qdict_join(options, old_options, false);
614 * Set open flags for a given discard mode
616 * Return 0 on success, -1 if the discard mode was invalid.
618 int bdrv_parse_discard_flags(const char *mode, int *flags)
620 *flags &= ~BDRV_O_UNMAP;
622 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) {
623 /* do nothing */
624 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) {
625 *flags |= BDRV_O_UNMAP;
626 } else {
627 return -1;
630 return 0;
634 * Set open flags for a given cache mode
636 * Return 0 on success, -1 if the cache mode was invalid.
638 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough)
640 *flags &= ~BDRV_O_CACHE_MASK;
642 if (!strcmp(mode, "off") || !strcmp(mode, "none")) {
643 *writethrough = false;
644 *flags |= BDRV_O_NOCACHE;
645 } else if (!strcmp(mode, "directsync")) {
646 *writethrough = true;
647 *flags |= BDRV_O_NOCACHE;
648 } else if (!strcmp(mode, "writeback")) {
649 *writethrough = false;
650 } else if (!strcmp(mode, "unsafe")) {
651 *writethrough = false;
652 *flags |= BDRV_O_NO_FLUSH;
653 } else if (!strcmp(mode, "writethrough")) {
654 *writethrough = true;
655 } else {
656 return -1;
659 return 0;
662 static void bdrv_child_cb_drained_begin(BdrvChild *child)
664 BlockDriverState *bs = child->opaque;
665 bdrv_drained_begin(bs);
668 static void bdrv_child_cb_drained_end(BdrvChild *child)
670 BlockDriverState *bs = child->opaque;
671 bdrv_drained_end(bs);
675 * Returns the options and flags that a temporary snapshot should get, based on
676 * the originally requested flags (the originally requested image will have
677 * flags like a backing file)
679 static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
680 int parent_flags, QDict *parent_options)
682 *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY;
684 /* For temporary files, unconditional cache=unsafe is fine */
685 qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off");
686 qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
688 /* aio=native doesn't work for cache.direct=off, so disable it for the
689 * temporary snapshot */
690 *child_flags &= ~BDRV_O_NATIVE_AIO;
694 * Returns the options and flags that bs->file should get if a protocol driver
695 * is expected, based on the given options and flags for the parent BDS
697 static void bdrv_inherited_options(int *child_flags, QDict *child_options,
698 int parent_flags, QDict *parent_options)
700 int flags = parent_flags;
702 /* Enable protocol handling, disable format probing for bs->file */
703 flags |= BDRV_O_PROTOCOL;
705 /* If the cache mode isn't explicitly set, inherit direct and no-flush from
706 * the parent. */
707 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
708 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
710 /* Our block drivers take care to send flushes and respect unmap policy,
711 * so we can default to enable both on lower layers regardless of the
712 * corresponding parent options. */
713 flags |= BDRV_O_UNMAP;
715 /* Clear flags that only apply to the top layer */
716 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ |
717 BDRV_O_NO_IO);
719 *child_flags = flags;
722 const BdrvChildRole child_file = {
723 .inherit_options = bdrv_inherited_options,
724 .drained_begin = bdrv_child_cb_drained_begin,
725 .drained_end = bdrv_child_cb_drained_end,
729 * Returns the options and flags that bs->file should get if the use of formats
730 * (and not only protocols) is permitted for it, based on the given options and
731 * flags for the parent BDS
733 static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options,
734 int parent_flags, QDict *parent_options)
736 child_file.inherit_options(child_flags, child_options,
737 parent_flags, parent_options);
739 *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO);
742 const BdrvChildRole child_format = {
743 .inherit_options = bdrv_inherited_fmt_options,
744 .drained_begin = bdrv_child_cb_drained_begin,
745 .drained_end = bdrv_child_cb_drained_end,
749 * Returns the options and flags that bs->backing should get, based on the
750 * given options and flags for the parent BDS
752 static void bdrv_backing_options(int *child_flags, QDict *child_options,
753 int parent_flags, QDict *parent_options)
755 int flags = parent_flags;
757 /* The cache mode is inherited unmodified for backing files; except WCE,
758 * which is only applied on the top level (BlockBackend) */
759 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
760 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
762 /* backing files always opened read-only */
763 flags &= ~(BDRV_O_RDWR | BDRV_O_COPY_ON_READ);
765 /* snapshot=on is handled on the top layer */
766 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY);
768 *child_flags = flags;
771 static const BdrvChildRole child_backing = {
772 .inherit_options = bdrv_backing_options,
773 .drained_begin = bdrv_child_cb_drained_begin,
774 .drained_end = bdrv_child_cb_drained_end,
777 static int bdrv_open_flags(BlockDriverState *bs, int flags)
779 int open_flags = flags;
782 * Clear flags that are internal to the block layer before opening the
783 * image.
785 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL);
788 * Snapshots should be writable.
790 if (flags & BDRV_O_TEMPORARY) {
791 open_flags |= BDRV_O_RDWR;
794 return open_flags;
797 static void update_flags_from_options(int *flags, QemuOpts *opts)
799 *flags &= ~BDRV_O_CACHE_MASK;
801 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_NO_FLUSH));
802 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
803 *flags |= BDRV_O_NO_FLUSH;
806 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT));
807 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_DIRECT, false)) {
808 *flags |= BDRV_O_NOCACHE;
812 static void update_options_from_flags(QDict *options, int flags)
814 if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) {
815 qdict_put(options, BDRV_OPT_CACHE_DIRECT,
816 qbool_from_bool(flags & BDRV_O_NOCACHE));
818 if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) {
819 qdict_put(options, BDRV_OPT_CACHE_NO_FLUSH,
820 qbool_from_bool(flags & BDRV_O_NO_FLUSH));
824 static void bdrv_assign_node_name(BlockDriverState *bs,
825 const char *node_name,
826 Error **errp)
828 char *gen_node_name = NULL;
830 if (!node_name) {
831 node_name = gen_node_name = id_generate(ID_BLOCK);
832 } else if (!id_wellformed(node_name)) {
834 * Check for empty string or invalid characters, but not if it is
835 * generated (generated names use characters not available to the user)
837 error_setg(errp, "Invalid node name");
838 return;
841 /* takes care of avoiding namespaces collisions */
842 if (blk_by_name(node_name)) {
843 error_setg(errp, "node-name=%s is conflicting with a device id",
844 node_name);
845 goto out;
848 /* takes care of avoiding duplicates node names */
849 if (bdrv_find_node(node_name)) {
850 error_setg(errp, "Duplicate node name");
851 goto out;
854 /* copy node name into the bs and insert it into the graph list */
855 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
856 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
857 out:
858 g_free(gen_node_name);
861 static QemuOptsList bdrv_runtime_opts = {
862 .name = "bdrv_common",
863 .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head),
864 .desc = {
866 .name = "node-name",
867 .type = QEMU_OPT_STRING,
868 .help = "Node name of the block device node",
871 .name = "driver",
872 .type = QEMU_OPT_STRING,
873 .help = "Block driver to use for the node",
876 .name = BDRV_OPT_CACHE_DIRECT,
877 .type = QEMU_OPT_BOOL,
878 .help = "Bypass software writeback cache on the host",
881 .name = BDRV_OPT_CACHE_NO_FLUSH,
882 .type = QEMU_OPT_BOOL,
883 .help = "Ignore flush requests",
885 { /* end of list */ }
890 * Common part for opening disk images and files
892 * Removes all processed options from *options.
894 static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file,
895 QDict *options, Error **errp)
897 int ret, open_flags;
898 const char *filename;
899 const char *driver_name = NULL;
900 const char *node_name = NULL;
901 QemuOpts *opts;
902 BlockDriver *drv;
903 Error *local_err = NULL;
905 assert(bs->file == NULL);
906 assert(options != NULL && bs->options != options);
908 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
909 qemu_opts_absorb_qdict(opts, options, &local_err);
910 if (local_err) {
911 error_propagate(errp, local_err);
912 ret = -EINVAL;
913 goto fail_opts;
916 driver_name = qemu_opt_get(opts, "driver");
917 drv = bdrv_find_format(driver_name);
918 assert(drv != NULL);
920 if (file != NULL) {
921 filename = file->bs->filename;
922 } else {
923 filename = qdict_get_try_str(options, "filename");
926 if (drv->bdrv_needs_filename && !filename) {
927 error_setg(errp, "The '%s' block driver requires a file name",
928 drv->format_name);
929 ret = -EINVAL;
930 goto fail_opts;
933 trace_bdrv_open_common(bs, filename ?: "", bs->open_flags,
934 drv->format_name);
936 node_name = qemu_opt_get(opts, "node-name");
937 bdrv_assign_node_name(bs, node_name, &local_err);
938 if (local_err) {
939 error_propagate(errp, local_err);
940 ret = -EINVAL;
941 goto fail_opts;
944 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
946 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
947 error_setg(errp,
948 !bs->read_only && bdrv_is_whitelisted(drv, true)
949 ? "Driver '%s' can only be used for read-only devices"
950 : "Driver '%s' is not whitelisted",
951 drv->format_name);
952 ret = -ENOTSUP;
953 goto fail_opts;
956 assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */
957 if (bs->open_flags & BDRV_O_COPY_ON_READ) {
958 if (!bs->read_only) {
959 bdrv_enable_copy_on_read(bs);
960 } else {
961 error_setg(errp, "Can't use copy-on-read on read-only device");
962 ret = -EINVAL;
963 goto fail_opts;
967 if (filename != NULL) {
968 pstrcpy(bs->filename, sizeof(bs->filename), filename);
969 } else {
970 bs->filename[0] = '\0';
972 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename);
974 bs->drv = drv;
975 bs->opaque = g_malloc0(drv->instance_size);
977 /* Apply cache mode options */
978 update_flags_from_options(&bs->open_flags, opts);
980 /* Open the image, either directly or using a protocol */
981 open_flags = bdrv_open_flags(bs, bs->open_flags);
982 if (drv->bdrv_file_open) {
983 assert(file == NULL);
984 assert(!drv->bdrv_needs_filename || filename != NULL);
985 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err);
986 } else {
987 if (file == NULL) {
988 error_setg(errp, "Can't use '%s' as a block driver for the "
989 "protocol level", drv->format_name);
990 ret = -EINVAL;
991 goto free_and_fail;
993 bs->file = file;
994 ret = drv->bdrv_open(bs, options, open_flags, &local_err);
997 if (ret < 0) {
998 if (local_err) {
999 error_propagate(errp, local_err);
1000 } else if (bs->filename[0]) {
1001 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename);
1002 } else {
1003 error_setg_errno(errp, -ret, "Could not open image");
1005 goto free_and_fail;
1008 ret = refresh_total_sectors(bs, bs->total_sectors);
1009 if (ret < 0) {
1010 error_setg_errno(errp, -ret, "Could not refresh total sector count");
1011 goto free_and_fail;
1014 bdrv_refresh_limits(bs, &local_err);
1015 if (local_err) {
1016 error_propagate(errp, local_err);
1017 ret = -EINVAL;
1018 goto free_and_fail;
1021 assert(bdrv_opt_mem_align(bs) != 0);
1022 assert(bdrv_min_mem_align(bs) != 0);
1023 assert(is_power_of_2(bs->bl.request_alignment));
1025 qemu_opts_del(opts);
1026 return 0;
1028 free_and_fail:
1029 bs->file = NULL;
1030 g_free(bs->opaque);
1031 bs->opaque = NULL;
1032 bs->drv = NULL;
1033 fail_opts:
1034 qemu_opts_del(opts);
1035 return ret;
1038 static QDict *parse_json_filename(const char *filename, Error **errp)
1040 QObject *options_obj;
1041 QDict *options;
1042 int ret;
1044 ret = strstart(filename, "json:", &filename);
1045 assert(ret);
1047 options_obj = qobject_from_json(filename);
1048 if (!options_obj) {
1049 error_setg(errp, "Could not parse the JSON options");
1050 return NULL;
1053 if (qobject_type(options_obj) != QTYPE_QDICT) {
1054 qobject_decref(options_obj);
1055 error_setg(errp, "Invalid JSON object given");
1056 return NULL;
1059 options = qobject_to_qdict(options_obj);
1060 qdict_flatten(options);
1062 return options;
1065 static void parse_json_protocol(QDict *options, const char **pfilename,
1066 Error **errp)
1068 QDict *json_options;
1069 Error *local_err = NULL;
1071 /* Parse json: pseudo-protocol */
1072 if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) {
1073 return;
1076 json_options = parse_json_filename(*pfilename, &local_err);
1077 if (local_err) {
1078 error_propagate(errp, local_err);
1079 return;
1082 /* Options given in the filename have lower priority than options
1083 * specified directly */
1084 qdict_join(options, json_options, false);
1085 QDECREF(json_options);
1086 *pfilename = NULL;
1090 * Fills in default options for opening images and converts the legacy
1091 * filename/flags pair to option QDict entries.
1092 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1093 * block driver has been specified explicitly.
1095 static int bdrv_fill_options(QDict **options, const char *filename,
1096 int *flags, Error **errp)
1098 const char *drvname;
1099 bool protocol = *flags & BDRV_O_PROTOCOL;
1100 bool parse_filename = false;
1101 BlockDriver *drv = NULL;
1102 Error *local_err = NULL;
1104 drvname = qdict_get_try_str(*options, "driver");
1105 if (drvname) {
1106 drv = bdrv_find_format(drvname);
1107 if (!drv) {
1108 error_setg(errp, "Unknown driver '%s'", drvname);
1109 return -ENOENT;
1111 /* If the user has explicitly specified the driver, this choice should
1112 * override the BDRV_O_PROTOCOL flag */
1113 protocol = drv->bdrv_file_open;
1116 if (protocol) {
1117 *flags |= BDRV_O_PROTOCOL;
1118 } else {
1119 *flags &= ~BDRV_O_PROTOCOL;
1122 /* Translate cache options from flags into options */
1123 update_options_from_flags(*options, *flags);
1125 /* Fetch the file name from the options QDict if necessary */
1126 if (protocol && filename) {
1127 if (!qdict_haskey(*options, "filename")) {
1128 qdict_put(*options, "filename", qstring_from_str(filename));
1129 parse_filename = true;
1130 } else {
1131 error_setg(errp, "Can't specify 'file' and 'filename' options at "
1132 "the same time");
1133 return -EINVAL;
1137 /* Find the right block driver */
1138 filename = qdict_get_try_str(*options, "filename");
1140 if (!drvname && protocol) {
1141 if (filename) {
1142 drv = bdrv_find_protocol(filename, parse_filename, errp);
1143 if (!drv) {
1144 return -EINVAL;
1147 drvname = drv->format_name;
1148 qdict_put(*options, "driver", qstring_from_str(drvname));
1149 } else {
1150 error_setg(errp, "Must specify either driver or file");
1151 return -EINVAL;
1155 assert(drv || !protocol);
1157 /* Driver-specific filename parsing */
1158 if (drv && drv->bdrv_parse_filename && parse_filename) {
1159 drv->bdrv_parse_filename(filename, *options, &local_err);
1160 if (local_err) {
1161 error_propagate(errp, local_err);
1162 return -EINVAL;
1165 if (!drv->bdrv_needs_filename) {
1166 qdict_del(*options, "filename");
1170 return 0;
1173 static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
1175 BlockDriverState *old_bs = child->bs;
1177 if (old_bs) {
1178 if (old_bs->quiesce_counter && child->role->drained_end) {
1179 child->role->drained_end(child);
1181 QLIST_REMOVE(child, next_parent);
1184 child->bs = new_bs;
1186 if (new_bs) {
1187 QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
1188 if (new_bs->quiesce_counter && child->role->drained_begin) {
1189 child->role->drained_begin(child);
1194 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
1195 const char *child_name,
1196 const BdrvChildRole *child_role,
1197 void *opaque)
1199 BdrvChild *child = g_new(BdrvChild, 1);
1200 *child = (BdrvChild) {
1201 .bs = NULL,
1202 .name = g_strdup(child_name),
1203 .role = child_role,
1204 .opaque = opaque,
1207 bdrv_replace_child(child, child_bs);
1209 return child;
1212 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
1213 BlockDriverState *child_bs,
1214 const char *child_name,
1215 const BdrvChildRole *child_role)
1217 BdrvChild *child = bdrv_root_attach_child(child_bs, child_name, child_role,
1218 parent_bs);
1219 QLIST_INSERT_HEAD(&parent_bs->children, child, next);
1220 return child;
1223 static void bdrv_detach_child(BdrvChild *child)
1225 if (child->next.le_prev) {
1226 QLIST_REMOVE(child, next);
1227 child->next.le_prev = NULL;
1230 bdrv_replace_child(child, NULL);
1232 g_free(child->name);
1233 g_free(child);
1236 void bdrv_root_unref_child(BdrvChild *child)
1238 BlockDriverState *child_bs;
1240 child_bs = child->bs;
1241 bdrv_detach_child(child);
1242 bdrv_unref(child_bs);
1245 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child)
1247 if (child == NULL) {
1248 return;
1251 if (child->bs->inherits_from == parent) {
1252 child->bs->inherits_from = NULL;
1255 bdrv_root_unref_child(child);
1259 static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load)
1261 BdrvChild *c;
1262 QLIST_FOREACH(c, &bs->parents, next_parent) {
1263 if (c->role->change_media) {
1264 c->role->change_media(c, load);
1269 static void bdrv_parent_cb_resize(BlockDriverState *bs)
1271 BdrvChild *c;
1272 QLIST_FOREACH(c, &bs->parents, next_parent) {
1273 if (c->role->resize) {
1274 c->role->resize(c);
1280 * Sets the backing file link of a BDS. A new reference is created; callers
1281 * which don't need their own reference any more must call bdrv_unref().
1283 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd)
1285 if (backing_hd) {
1286 bdrv_ref(backing_hd);
1289 if (bs->backing) {
1290 assert(bs->backing_blocker);
1291 bdrv_op_unblock_all(bs->backing->bs, bs->backing_blocker);
1292 bdrv_unref_child(bs, bs->backing);
1293 } else if (backing_hd) {
1294 error_setg(&bs->backing_blocker,
1295 "node is used as backing hd of '%s'",
1296 bdrv_get_device_or_node_name(bs));
1299 if (!backing_hd) {
1300 error_free(bs->backing_blocker);
1301 bs->backing_blocker = NULL;
1302 bs->backing = NULL;
1303 goto out;
1305 bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing);
1306 bs->open_flags &= ~BDRV_O_NO_BACKING;
1307 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_hd->filename);
1308 pstrcpy(bs->backing_format, sizeof(bs->backing_format),
1309 backing_hd->drv ? backing_hd->drv->format_name : "");
1311 bdrv_op_block_all(backing_hd, bs->backing_blocker);
1312 /* Otherwise we won't be able to commit due to check in bdrv_commit */
1313 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,
1314 bs->backing_blocker);
1315 out:
1316 bdrv_refresh_limits(bs, NULL);
1320 * Opens the backing file for a BlockDriverState if not yet open
1322 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
1323 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
1324 * itself, all options starting with "${bdref_key}." are considered part of the
1325 * BlockdevRef.
1327 * TODO Can this be unified with bdrv_open_image()?
1329 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
1330 const char *bdref_key, Error **errp)
1332 char *backing_filename = g_malloc0(PATH_MAX);
1333 char *bdref_key_dot;
1334 const char *reference = NULL;
1335 int ret = 0;
1336 BlockDriverState *backing_hd;
1337 QDict *options;
1338 QDict *tmp_parent_options = NULL;
1339 Error *local_err = NULL;
1341 if (bs->backing != NULL) {
1342 goto free_exit;
1345 /* NULL means an empty set of options */
1346 if (parent_options == NULL) {
1347 tmp_parent_options = qdict_new();
1348 parent_options = tmp_parent_options;
1351 bs->open_flags &= ~BDRV_O_NO_BACKING;
1353 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
1354 qdict_extract_subqdict(parent_options, &options, bdref_key_dot);
1355 g_free(bdref_key_dot);
1357 reference = qdict_get_try_str(parent_options, bdref_key);
1358 if (reference || qdict_haskey(options, "file.filename")) {
1359 backing_filename[0] = '\0';
1360 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
1361 QDECREF(options);
1362 goto free_exit;
1363 } else {
1364 bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX,
1365 &local_err);
1366 if (local_err) {
1367 ret = -EINVAL;
1368 error_propagate(errp, local_err);
1369 QDECREF(options);
1370 goto free_exit;
1374 if (!bs->drv || !bs->drv->supports_backing) {
1375 ret = -EINVAL;
1376 error_setg(errp, "Driver doesn't support backing files");
1377 QDECREF(options);
1378 goto free_exit;
1381 if (bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) {
1382 qdict_put(options, "driver", qstring_from_str(bs->backing_format));
1385 backing_hd = bdrv_open_inherit(*backing_filename ? backing_filename : NULL,
1386 reference, options, 0, bs, &child_backing,
1387 errp);
1388 if (!backing_hd) {
1389 bs->open_flags |= BDRV_O_NO_BACKING;
1390 error_prepend(errp, "Could not open backing file: ");
1391 ret = -EINVAL;
1392 goto free_exit;
1395 /* Hook up the backing file link; drop our reference, bs owns the
1396 * backing_hd reference now */
1397 bdrv_set_backing_hd(bs, backing_hd);
1398 bdrv_unref(backing_hd);
1400 qdict_del(parent_options, bdref_key);
1402 free_exit:
1403 g_free(backing_filename);
1404 QDECREF(tmp_parent_options);
1405 return ret;
1409 * Opens a disk image whose options are given as BlockdevRef in another block
1410 * device's options.
1412 * If allow_none is true, no image will be opened if filename is false and no
1413 * BlockdevRef is given. NULL will be returned, but errp remains unset.
1415 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
1416 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
1417 * itself, all options starting with "${bdref_key}." are considered part of the
1418 * BlockdevRef.
1420 * The BlockdevRef will be removed from the options QDict.
1422 BdrvChild *bdrv_open_child(const char *filename,
1423 QDict *options, const char *bdref_key,
1424 BlockDriverState* parent,
1425 const BdrvChildRole *child_role,
1426 bool allow_none, Error **errp)
1428 BdrvChild *c = NULL;
1429 BlockDriverState *bs;
1430 QDict *image_options;
1431 char *bdref_key_dot;
1432 const char *reference;
1434 assert(child_role != NULL);
1436 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
1437 qdict_extract_subqdict(options, &image_options, bdref_key_dot);
1438 g_free(bdref_key_dot);
1440 reference = qdict_get_try_str(options, bdref_key);
1441 if (!filename && !reference && !qdict_size(image_options)) {
1442 if (!allow_none) {
1443 error_setg(errp, "A block device must be specified for \"%s\"",
1444 bdref_key);
1446 QDECREF(image_options);
1447 goto done;
1450 bs = bdrv_open_inherit(filename, reference, image_options, 0,
1451 parent, child_role, errp);
1452 if (!bs) {
1453 goto done;
1456 c = bdrv_attach_child(parent, bs, bdref_key, child_role);
1458 done:
1459 qdict_del(options, bdref_key);
1460 return c;
1463 static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
1464 int flags,
1465 QDict *snapshot_options,
1466 Error **errp)
1468 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
1469 char *tmp_filename = g_malloc0(PATH_MAX + 1);
1470 int64_t total_size;
1471 QemuOpts *opts = NULL;
1472 BlockDriverState *bs_snapshot;
1473 int ret;
1475 /* if snapshot, we create a temporary backing file and open it
1476 instead of opening 'filename' directly */
1478 /* Get the required size from the image */
1479 total_size = bdrv_getlength(bs);
1480 if (total_size < 0) {
1481 error_setg_errno(errp, -total_size, "Could not get image size");
1482 goto out;
1485 /* Create the temporary image */
1486 ret = get_tmp_filename(tmp_filename, PATH_MAX + 1);
1487 if (ret < 0) {
1488 error_setg_errno(errp, -ret, "Could not get temporary filename");
1489 goto out;
1492 opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0,
1493 &error_abort);
1494 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort);
1495 ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp);
1496 qemu_opts_del(opts);
1497 if (ret < 0) {
1498 error_prepend(errp, "Could not create temporary overlay '%s': ",
1499 tmp_filename);
1500 goto out;
1503 /* Prepare options QDict for the temporary file */
1504 qdict_put(snapshot_options, "file.driver",
1505 qstring_from_str("file"));
1506 qdict_put(snapshot_options, "file.filename",
1507 qstring_from_str(tmp_filename));
1508 qdict_put(snapshot_options, "driver",
1509 qstring_from_str("qcow2"));
1511 bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp);
1512 snapshot_options = NULL;
1513 if (!bs_snapshot) {
1514 ret = -EINVAL;
1515 goto out;
1518 /* bdrv_append() consumes a strong reference to bs_snapshot (i.e. it will
1519 * call bdrv_unref() on it), so in order to be able to return one, we have
1520 * to increase bs_snapshot's refcount here */
1521 bdrv_ref(bs_snapshot);
1522 bdrv_append(bs_snapshot, bs);
1524 g_free(tmp_filename);
1525 return bs_snapshot;
1527 out:
1528 QDECREF(snapshot_options);
1529 g_free(tmp_filename);
1530 return NULL;
1534 * Opens a disk image (raw, qcow2, vmdk, ...)
1536 * options is a QDict of options to pass to the block drivers, or NULL for an
1537 * empty set of options. The reference to the QDict belongs to the block layer
1538 * after the call (even on failure), so if the caller intends to reuse the
1539 * dictionary, it needs to use QINCREF() before calling bdrv_open.
1541 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
1542 * If it is not NULL, the referenced BDS will be reused.
1544 * The reference parameter may be used to specify an existing block device which
1545 * should be opened. If specified, neither options nor a filename may be given,
1546 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
1548 static BlockDriverState *bdrv_open_inherit(const char *filename,
1549 const char *reference,
1550 QDict *options, int flags,
1551 BlockDriverState *parent,
1552 const BdrvChildRole *child_role,
1553 Error **errp)
1555 int ret;
1556 BdrvChild *file = NULL;
1557 BlockDriverState *bs;
1558 BlockDriver *drv = NULL;
1559 const char *drvname;
1560 const char *backing;
1561 Error *local_err = NULL;
1562 QDict *snapshot_options = NULL;
1563 int snapshot_flags = 0;
1565 assert(!child_role || !flags);
1566 assert(!child_role == !parent);
1568 if (reference) {
1569 bool options_non_empty = options ? qdict_size(options) : false;
1570 QDECREF(options);
1572 if (filename || options_non_empty) {
1573 error_setg(errp, "Cannot reference an existing block device with "
1574 "additional options or a new filename");
1575 return NULL;
1578 bs = bdrv_lookup_bs(reference, reference, errp);
1579 if (!bs) {
1580 return NULL;
1583 bdrv_ref(bs);
1584 return bs;
1587 bs = bdrv_new();
1589 /* NULL means an empty set of options */
1590 if (options == NULL) {
1591 options = qdict_new();
1594 /* json: syntax counts as explicit options, as if in the QDict */
1595 parse_json_protocol(options, &filename, &local_err);
1596 if (local_err) {
1597 goto fail;
1600 bs->explicit_options = qdict_clone_shallow(options);
1602 if (child_role) {
1603 bs->inherits_from = parent;
1604 child_role->inherit_options(&flags, options,
1605 parent->open_flags, parent->options);
1608 ret = bdrv_fill_options(&options, filename, &flags, &local_err);
1609 if (local_err) {
1610 goto fail;
1613 bs->open_flags = flags;
1614 bs->options = options;
1615 options = qdict_clone_shallow(options);
1617 /* Find the right image format driver */
1618 drvname = qdict_get_try_str(options, "driver");
1619 if (drvname) {
1620 drv = bdrv_find_format(drvname);
1621 if (!drv) {
1622 error_setg(errp, "Unknown driver: '%s'", drvname);
1623 goto fail;
1627 assert(drvname || !(flags & BDRV_O_PROTOCOL));
1629 backing = qdict_get_try_str(options, "backing");
1630 if (backing && *backing == '\0') {
1631 flags |= BDRV_O_NO_BACKING;
1632 qdict_del(options, "backing");
1635 /* Open image file without format layer */
1636 if ((flags & BDRV_O_PROTOCOL) == 0) {
1637 if (flags & BDRV_O_RDWR) {
1638 flags |= BDRV_O_ALLOW_RDWR;
1640 if (flags & BDRV_O_SNAPSHOT) {
1641 snapshot_options = qdict_new();
1642 bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options,
1643 flags, options);
1644 bdrv_backing_options(&flags, options, flags, options);
1647 bs->open_flags = flags;
1649 file = bdrv_open_child(filename, options, "file", bs,
1650 &child_file, true, &local_err);
1651 if (local_err) {
1652 goto fail;
1656 /* Image format probing */
1657 bs->probed = !drv;
1658 if (!drv && file) {
1659 ret = find_image_format(file, filename, &drv, &local_err);
1660 if (ret < 0) {
1661 goto fail;
1664 * This option update would logically belong in bdrv_fill_options(),
1665 * but we first need to open bs->file for the probing to work, while
1666 * opening bs->file already requires the (mostly) final set of options
1667 * so that cache mode etc. can be inherited.
1669 * Adding the driver later is somewhat ugly, but it's not an option
1670 * that would ever be inherited, so it's correct. We just need to make
1671 * sure to update both bs->options (which has the full effective
1672 * options for bs) and options (which has file.* already removed).
1674 qdict_put(bs->options, "driver", qstring_from_str(drv->format_name));
1675 qdict_put(options, "driver", qstring_from_str(drv->format_name));
1676 } else if (!drv) {
1677 error_setg(errp, "Must specify either driver or file");
1678 goto fail;
1681 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
1682 assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open);
1683 /* file must be NULL if a protocol BDS is about to be created
1684 * (the inverse results in an error message from bdrv_open_common()) */
1685 assert(!(flags & BDRV_O_PROTOCOL) || !file);
1687 /* Open the image */
1688 ret = bdrv_open_common(bs, file, options, &local_err);
1689 if (ret < 0) {
1690 goto fail;
1693 if (file && (bs->file != file)) {
1694 bdrv_unref_child(bs, file);
1695 file = NULL;
1698 /* If there is a backing file, use it */
1699 if ((flags & BDRV_O_NO_BACKING) == 0) {
1700 ret = bdrv_open_backing_file(bs, options, "backing", &local_err);
1701 if (ret < 0) {
1702 goto close_and_fail;
1706 bdrv_refresh_filename(bs);
1708 /* Check if any unknown options were used */
1709 if (options && (qdict_size(options) != 0)) {
1710 const QDictEntry *entry = qdict_first(options);
1711 if (flags & BDRV_O_PROTOCOL) {
1712 error_setg(errp, "Block protocol '%s' doesn't support the option "
1713 "'%s'", drv->format_name, entry->key);
1714 } else {
1715 error_setg(errp,
1716 "Block format '%s' does not support the option '%s'",
1717 drv->format_name, entry->key);
1720 goto close_and_fail;
1723 if (!bdrv_key_required(bs)) {
1724 bdrv_parent_cb_change_media(bs, true);
1725 } else if (!runstate_check(RUN_STATE_PRELAUNCH)
1726 && !runstate_check(RUN_STATE_INMIGRATE)
1727 && !runstate_check(RUN_STATE_PAUSED)) { /* HACK */
1728 error_setg(errp,
1729 "Guest must be stopped for opening of encrypted image");
1730 goto close_and_fail;
1733 QDECREF(options);
1735 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
1736 * temporary snapshot afterwards. */
1737 if (snapshot_flags) {
1738 BlockDriverState *snapshot_bs;
1739 snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags,
1740 snapshot_options, &local_err);
1741 snapshot_options = NULL;
1742 if (local_err) {
1743 goto close_and_fail;
1745 /* We are not going to return bs but the overlay on top of it
1746 * (snapshot_bs); thus, we have to drop the strong reference to bs
1747 * (which we obtained by calling bdrv_new()). bs will not be deleted,
1748 * though, because the overlay still has a reference to it. */
1749 bdrv_unref(bs);
1750 bs = snapshot_bs;
1753 return bs;
1755 fail:
1756 if (file != NULL) {
1757 bdrv_unref_child(bs, file);
1759 QDECREF(snapshot_options);
1760 QDECREF(bs->explicit_options);
1761 QDECREF(bs->options);
1762 QDECREF(options);
1763 bs->options = NULL;
1764 bdrv_unref(bs);
1765 error_propagate(errp, local_err);
1766 return NULL;
1768 close_and_fail:
1769 bdrv_unref(bs);
1770 QDECREF(snapshot_options);
1771 QDECREF(options);
1772 error_propagate(errp, local_err);
1773 return NULL;
1776 BlockDriverState *bdrv_open(const char *filename, const char *reference,
1777 QDict *options, int flags, Error **errp)
1779 return bdrv_open_inherit(filename, reference, options, flags, NULL,
1780 NULL, errp);
1783 typedef struct BlockReopenQueueEntry {
1784 bool prepared;
1785 BDRVReopenState state;
1786 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry;
1787 } BlockReopenQueueEntry;
1790 * Adds a BlockDriverState to a simple queue for an atomic, transactional
1791 * reopen of multiple devices.
1793 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT
1794 * already performed, or alternatively may be NULL a new BlockReopenQueue will
1795 * be created and initialized. This newly created BlockReopenQueue should be
1796 * passed back in for subsequent calls that are intended to be of the same
1797 * atomic 'set'.
1799 * bs is the BlockDriverState to add to the reopen queue.
1801 * options contains the changed options for the associated bs
1802 * (the BlockReopenQueue takes ownership)
1804 * flags contains the open flags for the associated bs
1806 * returns a pointer to bs_queue, which is either the newly allocated
1807 * bs_queue, or the existing bs_queue being used.
1810 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
1811 BlockDriverState *bs,
1812 QDict *options,
1813 int flags,
1814 const BdrvChildRole *role,
1815 QDict *parent_options,
1816 int parent_flags)
1818 assert(bs != NULL);
1820 BlockReopenQueueEntry *bs_entry;
1821 BdrvChild *child;
1822 QDict *old_options, *explicit_options;
1824 if (bs_queue == NULL) {
1825 bs_queue = g_new0(BlockReopenQueue, 1);
1826 QSIMPLEQ_INIT(bs_queue);
1829 if (!options) {
1830 options = qdict_new();
1834 * Precedence of options:
1835 * 1. Explicitly passed in options (highest)
1836 * 2. Set in flags (only for top level)
1837 * 3. Retained from explicitly set options of bs
1838 * 4. Inherited from parent node
1839 * 5. Retained from effective options of bs
1842 if (!parent_options) {
1844 * Any setting represented by flags is always updated. If the
1845 * corresponding QDict option is set, it takes precedence. Otherwise
1846 * the flag is translated into a QDict option. The old setting of bs is
1847 * not considered.
1849 update_options_from_flags(options, flags);
1852 /* Old explicitly set values (don't overwrite by inherited value) */
1853 old_options = qdict_clone_shallow(bs->explicit_options);
1854 bdrv_join_options(bs, options, old_options);
1855 QDECREF(old_options);
1857 explicit_options = qdict_clone_shallow(options);
1859 /* Inherit from parent node */
1860 if (parent_options) {
1861 assert(!flags);
1862 role->inherit_options(&flags, options, parent_flags, parent_options);
1865 /* Old values are used for options that aren't set yet */
1866 old_options = qdict_clone_shallow(bs->options);
1867 bdrv_join_options(bs, options, old_options);
1868 QDECREF(old_options);
1870 /* bdrv_open() masks this flag out */
1871 flags &= ~BDRV_O_PROTOCOL;
1873 QLIST_FOREACH(child, &bs->children, next) {
1874 QDict *new_child_options;
1875 char *child_key_dot;
1877 /* reopen can only change the options of block devices that were
1878 * implicitly created and inherited options. For other (referenced)
1879 * block devices, a syntax like "backing.foo" results in an error. */
1880 if (child->bs->inherits_from != bs) {
1881 continue;
1884 child_key_dot = g_strdup_printf("%s.", child->name);
1885 qdict_extract_subqdict(options, &new_child_options, child_key_dot);
1886 g_free(child_key_dot);
1888 bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options, 0,
1889 child->role, options, flags);
1892 bs_entry = g_new0(BlockReopenQueueEntry, 1);
1893 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry);
1895 bs_entry->state.bs = bs;
1896 bs_entry->state.options = options;
1897 bs_entry->state.explicit_options = explicit_options;
1898 bs_entry->state.flags = flags;
1900 return bs_queue;
1903 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
1904 BlockDriverState *bs,
1905 QDict *options, int flags)
1907 return bdrv_reopen_queue_child(bs_queue, bs, options, flags,
1908 NULL, NULL, 0);
1912 * Reopen multiple BlockDriverStates atomically & transactionally.
1914 * The queue passed in (bs_queue) must have been built up previous
1915 * via bdrv_reopen_queue().
1917 * Reopens all BDS specified in the queue, with the appropriate
1918 * flags. All devices are prepared for reopen, and failure of any
1919 * device will cause all device changes to be abandonded, and intermediate
1920 * data cleaned up.
1922 * If all devices prepare successfully, then the changes are committed
1923 * to all devices.
1926 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
1928 int ret = -1;
1929 BlockReopenQueueEntry *bs_entry, *next;
1930 Error *local_err = NULL;
1932 assert(bs_queue != NULL);
1934 bdrv_drain_all();
1936 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
1937 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) {
1938 error_propagate(errp, local_err);
1939 goto cleanup;
1941 bs_entry->prepared = true;
1944 /* If we reach this point, we have success and just need to apply the
1945 * changes
1947 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
1948 bdrv_reopen_commit(&bs_entry->state);
1951 ret = 0;
1953 cleanup:
1954 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
1955 if (ret && bs_entry->prepared) {
1956 bdrv_reopen_abort(&bs_entry->state);
1957 } else if (ret) {
1958 QDECREF(bs_entry->state.explicit_options);
1960 QDECREF(bs_entry->state.options);
1961 g_free(bs_entry);
1963 g_free(bs_queue);
1964 return ret;
1968 /* Reopen a single BlockDriverState with the specified flags. */
1969 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp)
1971 int ret = -1;
1972 Error *local_err = NULL;
1973 BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags);
1975 ret = bdrv_reopen_multiple(queue, &local_err);
1976 if (local_err != NULL) {
1977 error_propagate(errp, local_err);
1979 return ret;
1984 * Prepares a BlockDriverState for reopen. All changes are staged in the
1985 * 'opaque' field of the BDRVReopenState, which is used and allocated by
1986 * the block driver layer .bdrv_reopen_prepare()
1988 * bs is the BlockDriverState to reopen
1989 * flags are the new open flags
1990 * queue is the reopen queue
1992 * Returns 0 on success, non-zero on error. On error errp will be set
1993 * as well.
1995 * On failure, bdrv_reopen_abort() will be called to clean up any data.
1996 * It is the responsibility of the caller to then call the abort() or
1997 * commit() for any other BDS that have been left in a prepare() state
2000 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
2001 Error **errp)
2003 int ret = -1;
2004 Error *local_err = NULL;
2005 BlockDriver *drv;
2006 QemuOpts *opts;
2007 const char *value;
2009 assert(reopen_state != NULL);
2010 assert(reopen_state->bs->drv != NULL);
2011 drv = reopen_state->bs->drv;
2013 /* Process generic block layer options */
2014 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
2015 qemu_opts_absorb_qdict(opts, reopen_state->options, &local_err);
2016 if (local_err) {
2017 error_propagate(errp, local_err);
2018 ret = -EINVAL;
2019 goto error;
2022 update_flags_from_options(&reopen_state->flags, opts);
2024 /* node-name and driver must be unchanged. Put them back into the QDict, so
2025 * that they are checked at the end of this function. */
2026 value = qemu_opt_get(opts, "node-name");
2027 if (value) {
2028 qdict_put(reopen_state->options, "node-name", qstring_from_str(value));
2031 value = qemu_opt_get(opts, "driver");
2032 if (value) {
2033 qdict_put(reopen_state->options, "driver", qstring_from_str(value));
2036 /* if we are to stay read-only, do not allow permission change
2037 * to r/w */
2038 if (!(reopen_state->bs->open_flags & BDRV_O_ALLOW_RDWR) &&
2039 reopen_state->flags & BDRV_O_RDWR) {
2040 error_setg(errp, "Node '%s' is read only",
2041 bdrv_get_device_or_node_name(reopen_state->bs));
2042 goto error;
2046 ret = bdrv_flush(reopen_state->bs);
2047 if (ret) {
2048 error_setg_errno(errp, -ret, "Error flushing drive");
2049 goto error;
2052 if (drv->bdrv_reopen_prepare) {
2053 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err);
2054 if (ret) {
2055 if (local_err != NULL) {
2056 error_propagate(errp, local_err);
2057 } else {
2058 error_setg(errp, "failed while preparing to reopen image '%s'",
2059 reopen_state->bs->filename);
2061 goto error;
2063 } else {
2064 /* It is currently mandatory to have a bdrv_reopen_prepare()
2065 * handler for each supported drv. */
2066 error_setg(errp, "Block format '%s' used by node '%s' "
2067 "does not support reopening files", drv->format_name,
2068 bdrv_get_device_or_node_name(reopen_state->bs));
2069 ret = -1;
2070 goto error;
2073 /* Options that are not handled are only okay if they are unchanged
2074 * compared to the old state. It is expected that some options are only
2075 * used for the initial open, but not reopen (e.g. filename) */
2076 if (qdict_size(reopen_state->options)) {
2077 const QDictEntry *entry = qdict_first(reopen_state->options);
2079 do {
2080 QString *new_obj = qobject_to_qstring(entry->value);
2081 const char *new = qstring_get_str(new_obj);
2082 const char *old = qdict_get_try_str(reopen_state->bs->options,
2083 entry->key);
2085 if (!old || strcmp(new, old)) {
2086 error_setg(errp, "Cannot change the option '%s'", entry->key);
2087 ret = -EINVAL;
2088 goto error;
2090 } while ((entry = qdict_next(reopen_state->options, entry)));
2093 ret = 0;
2095 error:
2096 qemu_opts_del(opts);
2097 return ret;
2101 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
2102 * makes them final by swapping the staging BlockDriverState contents into
2103 * the active BlockDriverState contents.
2105 void bdrv_reopen_commit(BDRVReopenState *reopen_state)
2107 BlockDriver *drv;
2109 assert(reopen_state != NULL);
2110 drv = reopen_state->bs->drv;
2111 assert(drv != NULL);
2113 /* If there are any driver level actions to take */
2114 if (drv->bdrv_reopen_commit) {
2115 drv->bdrv_reopen_commit(reopen_state);
2118 /* set BDS specific flags now */
2119 QDECREF(reopen_state->bs->explicit_options);
2121 reopen_state->bs->explicit_options = reopen_state->explicit_options;
2122 reopen_state->bs->open_flags = reopen_state->flags;
2123 reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
2125 bdrv_refresh_limits(reopen_state->bs, NULL);
2129 * Abort the reopen, and delete and free the staged changes in
2130 * reopen_state
2132 void bdrv_reopen_abort(BDRVReopenState *reopen_state)
2134 BlockDriver *drv;
2136 assert(reopen_state != NULL);
2137 drv = reopen_state->bs->drv;
2138 assert(drv != NULL);
2140 if (drv->bdrv_reopen_abort) {
2141 drv->bdrv_reopen_abort(reopen_state);
2144 QDECREF(reopen_state->explicit_options);
2148 static void bdrv_close(BlockDriverState *bs)
2150 BdrvAioNotifier *ban, *ban_next;
2152 assert(!bs->job);
2153 assert(!bs->refcnt);
2155 bdrv_drained_begin(bs); /* complete I/O */
2156 bdrv_flush(bs);
2157 bdrv_drain(bs); /* in case flush left pending I/O */
2159 bdrv_release_named_dirty_bitmaps(bs);
2160 assert(QLIST_EMPTY(&bs->dirty_bitmaps));
2162 if (bs->drv) {
2163 BdrvChild *child, *next;
2165 bs->drv->bdrv_close(bs);
2166 bs->drv = NULL;
2168 bdrv_set_backing_hd(bs, NULL);
2170 if (bs->file != NULL) {
2171 bdrv_unref_child(bs, bs->file);
2172 bs->file = NULL;
2175 QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
2176 /* TODO Remove bdrv_unref() from drivers' close function and use
2177 * bdrv_unref_child() here */
2178 if (child->bs->inherits_from == bs) {
2179 child->bs->inherits_from = NULL;
2181 bdrv_detach_child(child);
2184 g_free(bs->opaque);
2185 bs->opaque = NULL;
2186 bs->copy_on_read = 0;
2187 bs->backing_file[0] = '\0';
2188 bs->backing_format[0] = '\0';
2189 bs->total_sectors = 0;
2190 bs->encrypted = false;
2191 bs->valid_key = false;
2192 bs->sg = false;
2193 QDECREF(bs->options);
2194 QDECREF(bs->explicit_options);
2195 bs->options = NULL;
2196 QDECREF(bs->full_open_options);
2197 bs->full_open_options = NULL;
2200 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
2201 g_free(ban);
2203 QLIST_INIT(&bs->aio_notifiers);
2204 bdrv_drained_end(bs);
2207 void bdrv_close_all(void)
2209 block_job_cancel_sync_all();
2210 nbd_export_close_all();
2212 /* Drop references from requests still in flight, such as canceled block
2213 * jobs whose AIO context has not been polled yet */
2214 bdrv_drain_all();
2216 blk_remove_all_bs();
2217 blockdev_close_all_bdrv_states();
2219 assert(QTAILQ_EMPTY(&all_bdrv_states));
2222 static void change_parent_backing_link(BlockDriverState *from,
2223 BlockDriverState *to)
2225 BdrvChild *c, *next, *to_c;
2227 QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
2228 if (c->role == &child_backing) {
2229 /* @from is generally not allowed to be a backing file, except for
2230 * when @to is the overlay. In that case, @from may not be replaced
2231 * by @to as @to's backing node. */
2232 QLIST_FOREACH(to_c, &to->children, next) {
2233 if (to_c == c) {
2234 break;
2237 if (to_c) {
2238 continue;
2242 assert(c->role != &child_backing);
2243 bdrv_ref(to);
2244 bdrv_replace_child(c, to);
2245 bdrv_unref(from);
2250 * Add new bs contents at the top of an image chain while the chain is
2251 * live, while keeping required fields on the top layer.
2253 * This will modify the BlockDriverState fields, and swap contents
2254 * between bs_new and bs_top. Both bs_new and bs_top are modified.
2256 * bs_new must not be attached to a BlockBackend.
2258 * This function does not create any image files.
2260 * bdrv_append() takes ownership of a bs_new reference and unrefs it because
2261 * that's what the callers commonly need. bs_new will be referenced by the old
2262 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a
2263 * reference of its own, it must call bdrv_ref().
2265 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top)
2267 assert(!bdrv_requests_pending(bs_top));
2268 assert(!bdrv_requests_pending(bs_new));
2270 bdrv_ref(bs_top);
2272 change_parent_backing_link(bs_top, bs_new);
2273 bdrv_set_backing_hd(bs_new, bs_top);
2274 bdrv_unref(bs_top);
2276 /* bs_new is now referenced by its new parents, we don't need the
2277 * additional reference any more. */
2278 bdrv_unref(bs_new);
2281 void bdrv_replace_in_backing_chain(BlockDriverState *old, BlockDriverState *new)
2283 assert(!bdrv_requests_pending(old));
2284 assert(!bdrv_requests_pending(new));
2286 bdrv_ref(old);
2288 change_parent_backing_link(old, new);
2290 bdrv_unref(old);
2293 static void bdrv_delete(BlockDriverState *bs)
2295 assert(!bs->job);
2296 assert(bdrv_op_blocker_is_empty(bs));
2297 assert(!bs->refcnt);
2299 bdrv_close(bs);
2301 /* remove from list, if necessary */
2302 if (bs->node_name[0] != '\0') {
2303 QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list);
2305 QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list);
2307 g_free(bs);
2311 * Run consistency checks on an image
2313 * Returns 0 if the check could be completed (it doesn't mean that the image is
2314 * free of errors) or -errno when an internal error occurred. The results of the
2315 * check are stored in res.
2317 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix)
2319 if (bs->drv == NULL) {
2320 return -ENOMEDIUM;
2322 if (bs->drv->bdrv_check == NULL) {
2323 return -ENOTSUP;
2326 memset(res, 0, sizeof(*res));
2327 return bs->drv->bdrv_check(bs, res, fix);
2331 * Return values:
2332 * 0 - success
2333 * -EINVAL - backing format specified, but no file
2334 * -ENOSPC - can't update the backing file because no space is left in the
2335 * image file header
2336 * -ENOTSUP - format driver doesn't support changing the backing file
2338 int bdrv_change_backing_file(BlockDriverState *bs,
2339 const char *backing_file, const char *backing_fmt)
2341 BlockDriver *drv = bs->drv;
2342 int ret;
2344 /* Backing file format doesn't make sense without a backing file */
2345 if (backing_fmt && !backing_file) {
2346 return -EINVAL;
2349 if (drv->bdrv_change_backing_file != NULL) {
2350 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
2351 } else {
2352 ret = -ENOTSUP;
2355 if (ret == 0) {
2356 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
2357 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
2359 return ret;
2363 * Finds the image layer in the chain that has 'bs' as its backing file.
2365 * active is the current topmost image.
2367 * Returns NULL if bs is not found in active's image chain,
2368 * or if active == bs.
2370 * Returns the bottommost base image if bs == NULL.
2372 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
2373 BlockDriverState *bs)
2375 while (active && bs != backing_bs(active)) {
2376 active = backing_bs(active);
2379 return active;
2382 /* Given a BDS, searches for the base layer. */
2383 BlockDriverState *bdrv_find_base(BlockDriverState *bs)
2385 return bdrv_find_overlay(bs, NULL);
2389 * Drops images above 'base' up to and including 'top', and sets the image
2390 * above 'top' to have base as its backing file.
2392 * Requires that the overlay to 'top' is opened r/w, so that the backing file
2393 * information in 'bs' can be properly updated.
2395 * E.g., this will convert the following chain:
2396 * bottom <- base <- intermediate <- top <- active
2398 * to
2400 * bottom <- base <- active
2402 * It is allowed for bottom==base, in which case it converts:
2404 * base <- intermediate <- top <- active
2406 * to
2408 * base <- active
2410 * If backing_file_str is non-NULL, it will be used when modifying top's
2411 * overlay image metadata.
2413 * Error conditions:
2414 * if active == top, that is considered an error
2417 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
2418 BlockDriverState *base, const char *backing_file_str)
2420 BlockDriverState *new_top_bs = NULL;
2421 int ret = -EIO;
2423 if (!top->drv || !base->drv) {
2424 goto exit;
2427 new_top_bs = bdrv_find_overlay(active, top);
2429 if (new_top_bs == NULL) {
2430 /* we could not find the image above 'top', this is an error */
2431 goto exit;
2434 /* special case of new_top_bs->backing->bs already pointing to base - nothing
2435 * to do, no intermediate images */
2436 if (backing_bs(new_top_bs) == base) {
2437 ret = 0;
2438 goto exit;
2441 /* Make sure that base is in the backing chain of top */
2442 if (!bdrv_chain_contains(top, base)) {
2443 goto exit;
2446 /* success - we can delete the intermediate states, and link top->base */
2447 backing_file_str = backing_file_str ? backing_file_str : base->filename;
2448 ret = bdrv_change_backing_file(new_top_bs, backing_file_str,
2449 base->drv ? base->drv->format_name : "");
2450 if (ret) {
2451 goto exit;
2453 bdrv_set_backing_hd(new_top_bs, base);
2455 ret = 0;
2456 exit:
2457 return ret;
2461 * Truncate file to 'offset' bytes (needed only for file protocols)
2463 int bdrv_truncate(BlockDriverState *bs, int64_t offset)
2465 BlockDriver *drv = bs->drv;
2466 int ret;
2467 if (!drv)
2468 return -ENOMEDIUM;
2469 if (!drv->bdrv_truncate)
2470 return -ENOTSUP;
2471 if (bs->read_only)
2472 return -EACCES;
2474 ret = drv->bdrv_truncate(bs, offset);
2475 if (ret == 0) {
2476 ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
2477 bdrv_dirty_bitmap_truncate(bs);
2478 bdrv_parent_cb_resize(bs);
2479 ++bs->write_gen;
2481 return ret;
2485 * Length of a allocated file in bytes. Sparse files are counted by actual
2486 * allocated space. Return < 0 if error or unknown.
2488 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs)
2490 BlockDriver *drv = bs->drv;
2491 if (!drv) {
2492 return -ENOMEDIUM;
2494 if (drv->bdrv_get_allocated_file_size) {
2495 return drv->bdrv_get_allocated_file_size(bs);
2497 if (bs->file) {
2498 return bdrv_get_allocated_file_size(bs->file->bs);
2500 return -ENOTSUP;
2504 * Return number of sectors on success, -errno on error.
2506 int64_t bdrv_nb_sectors(BlockDriverState *bs)
2508 BlockDriver *drv = bs->drv;
2510 if (!drv)
2511 return -ENOMEDIUM;
2513 if (drv->has_variable_length) {
2514 int ret = refresh_total_sectors(bs, bs->total_sectors);
2515 if (ret < 0) {
2516 return ret;
2519 return bs->total_sectors;
2523 * Return length in bytes on success, -errno on error.
2524 * The length is always a multiple of BDRV_SECTOR_SIZE.
2526 int64_t bdrv_getlength(BlockDriverState *bs)
2528 int64_t ret = bdrv_nb_sectors(bs);
2530 ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret;
2531 return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE;
2534 /* return 0 as number of sectors if no device present or error */
2535 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
2537 int64_t nb_sectors = bdrv_nb_sectors(bs);
2539 *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors;
2542 bool bdrv_is_read_only(BlockDriverState *bs)
2544 return bs->read_only;
2547 bool bdrv_is_sg(BlockDriverState *bs)
2549 return bs->sg;
2552 bool bdrv_is_encrypted(BlockDriverState *bs)
2554 if (bs->backing && bs->backing->bs->encrypted) {
2555 return true;
2557 return bs->encrypted;
2560 bool bdrv_key_required(BlockDriverState *bs)
2562 BdrvChild *backing = bs->backing;
2564 if (backing && backing->bs->encrypted && !backing->bs->valid_key) {
2565 return true;
2567 return (bs->encrypted && !bs->valid_key);
2570 int bdrv_set_key(BlockDriverState *bs, const char *key)
2572 int ret;
2573 if (bs->backing && bs->backing->bs->encrypted) {
2574 ret = bdrv_set_key(bs->backing->bs, key);
2575 if (ret < 0)
2576 return ret;
2577 if (!bs->encrypted)
2578 return 0;
2580 if (!bs->encrypted) {
2581 return -EINVAL;
2582 } else if (!bs->drv || !bs->drv->bdrv_set_key) {
2583 return -ENOMEDIUM;
2585 ret = bs->drv->bdrv_set_key(bs, key);
2586 if (ret < 0) {
2587 bs->valid_key = false;
2588 } else if (!bs->valid_key) {
2589 /* call the change callback now, we skipped it on open */
2590 bs->valid_key = true;
2591 bdrv_parent_cb_change_media(bs, true);
2593 return ret;
2597 * Provide an encryption key for @bs.
2598 * If @key is non-null:
2599 * If @bs is not encrypted, fail.
2600 * Else if the key is invalid, fail.
2601 * Else set @bs's key to @key, replacing the existing key, if any.
2602 * If @key is null:
2603 * If @bs is encrypted and still lacks a key, fail.
2604 * Else do nothing.
2605 * On failure, store an error object through @errp if non-null.
2607 void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp)
2609 if (key) {
2610 if (!bdrv_is_encrypted(bs)) {
2611 error_setg(errp, "Node '%s' is not encrypted",
2612 bdrv_get_device_or_node_name(bs));
2613 } else if (bdrv_set_key(bs, key) < 0) {
2614 error_setg(errp, QERR_INVALID_PASSWORD);
2616 } else {
2617 if (bdrv_key_required(bs)) {
2618 error_set(errp, ERROR_CLASS_DEVICE_ENCRYPTED,
2619 "'%s' (%s) is encrypted",
2620 bdrv_get_device_or_node_name(bs),
2621 bdrv_get_encrypted_filename(bs));
2626 const char *bdrv_get_format_name(BlockDriverState *bs)
2628 return bs->drv ? bs->drv->format_name : NULL;
2631 static int qsort_strcmp(const void *a, const void *b)
2633 return strcmp(a, b);
2636 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
2637 void *opaque)
2639 BlockDriver *drv;
2640 int count = 0;
2641 int i;
2642 const char **formats = NULL;
2644 QLIST_FOREACH(drv, &bdrv_drivers, list) {
2645 if (drv->format_name) {
2646 bool found = false;
2647 int i = count;
2648 while (formats && i && !found) {
2649 found = !strcmp(formats[--i], drv->format_name);
2652 if (!found) {
2653 formats = g_renew(const char *, formats, count + 1);
2654 formats[count++] = drv->format_name;
2659 qsort(formats, count, sizeof(formats[0]), qsort_strcmp);
2661 for (i = 0; i < count; i++) {
2662 it(opaque, formats[i]);
2665 g_free(formats);
2668 /* This function is to find a node in the bs graph */
2669 BlockDriverState *bdrv_find_node(const char *node_name)
2671 BlockDriverState *bs;
2673 assert(node_name);
2675 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
2676 if (!strcmp(node_name, bs->node_name)) {
2677 return bs;
2680 return NULL;
2683 /* Put this QMP function here so it can access the static graph_bdrv_states. */
2684 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp)
2686 BlockDeviceInfoList *list, *entry;
2687 BlockDriverState *bs;
2689 list = NULL;
2690 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
2691 BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, errp);
2692 if (!info) {
2693 qapi_free_BlockDeviceInfoList(list);
2694 return NULL;
2696 entry = g_malloc0(sizeof(*entry));
2697 entry->value = info;
2698 entry->next = list;
2699 list = entry;
2702 return list;
2705 BlockDriverState *bdrv_lookup_bs(const char *device,
2706 const char *node_name,
2707 Error **errp)
2709 BlockBackend *blk;
2710 BlockDriverState *bs;
2712 if (device) {
2713 blk = blk_by_name(device);
2715 if (blk) {
2716 bs = blk_bs(blk);
2717 if (!bs) {
2718 error_setg(errp, "Device '%s' has no medium", device);
2721 return bs;
2725 if (node_name) {
2726 bs = bdrv_find_node(node_name);
2728 if (bs) {
2729 return bs;
2733 error_setg(errp, "Cannot find device=%s nor node_name=%s",
2734 device ? device : "",
2735 node_name ? node_name : "");
2736 return NULL;
2739 /* If 'base' is in the same chain as 'top', return true. Otherwise,
2740 * return false. If either argument is NULL, return false. */
2741 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base)
2743 while (top && top != base) {
2744 top = backing_bs(top);
2747 return top != NULL;
2750 BlockDriverState *bdrv_next_node(BlockDriverState *bs)
2752 if (!bs) {
2753 return QTAILQ_FIRST(&graph_bdrv_states);
2755 return QTAILQ_NEXT(bs, node_list);
2758 const char *bdrv_get_node_name(const BlockDriverState *bs)
2760 return bs->node_name;
2763 const char *bdrv_get_parent_name(const BlockDriverState *bs)
2765 BdrvChild *c;
2766 const char *name;
2768 /* If multiple parents have a name, just pick the first one. */
2769 QLIST_FOREACH(c, &bs->parents, next_parent) {
2770 if (c->role->get_name) {
2771 name = c->role->get_name(c);
2772 if (name && *name) {
2773 return name;
2778 return NULL;
2781 /* TODO check what callers really want: bs->node_name or blk_name() */
2782 const char *bdrv_get_device_name(const BlockDriverState *bs)
2784 return bdrv_get_parent_name(bs) ?: "";
2787 /* This can be used to identify nodes that might not have a device
2788 * name associated. Since node and device names live in the same
2789 * namespace, the result is unambiguous. The exception is if both are
2790 * absent, then this returns an empty (non-null) string. */
2791 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs)
2793 return bdrv_get_parent_name(bs) ?: bs->node_name;
2796 int bdrv_get_flags(BlockDriverState *bs)
2798 return bs->open_flags;
2801 int bdrv_has_zero_init_1(BlockDriverState *bs)
2803 return 1;
2806 int bdrv_has_zero_init(BlockDriverState *bs)
2808 assert(bs->drv);
2810 /* If BS is a copy on write image, it is initialized to
2811 the contents of the base image, which may not be zeroes. */
2812 if (bs->backing) {
2813 return 0;
2815 if (bs->drv->bdrv_has_zero_init) {
2816 return bs->drv->bdrv_has_zero_init(bs);
2819 /* safe default */
2820 return 0;
2823 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs)
2825 BlockDriverInfo bdi;
2827 if (bs->backing) {
2828 return false;
2831 if (bdrv_get_info(bs, &bdi) == 0) {
2832 return bdi.unallocated_blocks_are_zero;
2835 return false;
2838 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
2840 BlockDriverInfo bdi;
2842 if (!(bs->open_flags & BDRV_O_UNMAP)) {
2843 return false;
2846 if (bdrv_get_info(bs, &bdi) == 0) {
2847 return bdi.can_write_zeroes_with_unmap;
2850 return false;
2853 const char *bdrv_get_encrypted_filename(BlockDriverState *bs)
2855 if (bs->backing && bs->backing->bs->encrypted)
2856 return bs->backing_file;
2857 else if (bs->encrypted)
2858 return bs->filename;
2859 else
2860 return NULL;
2863 void bdrv_get_backing_filename(BlockDriverState *bs,
2864 char *filename, int filename_size)
2866 pstrcpy(filename, filename_size, bs->backing_file);
2869 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
2871 BlockDriver *drv = bs->drv;
2872 if (!drv)
2873 return -ENOMEDIUM;
2874 if (!drv->bdrv_get_info)
2875 return -ENOTSUP;
2876 memset(bdi, 0, sizeof(*bdi));
2877 return drv->bdrv_get_info(bs, bdi);
2880 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs)
2882 BlockDriver *drv = bs->drv;
2883 if (drv && drv->bdrv_get_specific_info) {
2884 return drv->bdrv_get_specific_info(bs);
2886 return NULL;
2889 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event)
2891 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
2892 return;
2895 bs->drv->bdrv_debug_event(bs, event);
2898 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
2899 const char *tag)
2901 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) {
2902 bs = bs->file ? bs->file->bs : NULL;
2905 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) {
2906 return bs->drv->bdrv_debug_breakpoint(bs, event, tag);
2909 return -ENOTSUP;
2912 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag)
2914 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) {
2915 bs = bs->file ? bs->file->bs : NULL;
2918 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) {
2919 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag);
2922 return -ENOTSUP;
2925 int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
2927 while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) {
2928 bs = bs->file ? bs->file->bs : NULL;
2931 if (bs && bs->drv && bs->drv->bdrv_debug_resume) {
2932 return bs->drv->bdrv_debug_resume(bs, tag);
2935 return -ENOTSUP;
2938 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag)
2940 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) {
2941 bs = bs->file ? bs->file->bs : NULL;
2944 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) {
2945 return bs->drv->bdrv_debug_is_suspended(bs, tag);
2948 return false;
2951 int bdrv_is_snapshot(BlockDriverState *bs)
2953 return !!(bs->open_flags & BDRV_O_SNAPSHOT);
2956 /* backing_file can either be relative, or absolute, or a protocol. If it is
2957 * relative, it must be relative to the chain. So, passing in bs->filename
2958 * from a BDS as backing_file should not be done, as that may be relative to
2959 * the CWD rather than the chain. */
2960 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
2961 const char *backing_file)
2963 char *filename_full = NULL;
2964 char *backing_file_full = NULL;
2965 char *filename_tmp = NULL;
2966 int is_protocol = 0;
2967 BlockDriverState *curr_bs = NULL;
2968 BlockDriverState *retval = NULL;
2970 if (!bs || !bs->drv || !backing_file) {
2971 return NULL;
2974 filename_full = g_malloc(PATH_MAX);
2975 backing_file_full = g_malloc(PATH_MAX);
2976 filename_tmp = g_malloc(PATH_MAX);
2978 is_protocol = path_has_protocol(backing_file);
2980 for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) {
2982 /* If either of the filename paths is actually a protocol, then
2983 * compare unmodified paths; otherwise make paths relative */
2984 if (is_protocol || path_has_protocol(curr_bs->backing_file)) {
2985 if (strcmp(backing_file, curr_bs->backing_file) == 0) {
2986 retval = curr_bs->backing->bs;
2987 break;
2989 } else {
2990 /* If not an absolute filename path, make it relative to the current
2991 * image's filename path */
2992 path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
2993 backing_file);
2995 /* We are going to compare absolute pathnames */
2996 if (!realpath(filename_tmp, filename_full)) {
2997 continue;
3000 /* We need to make sure the backing filename we are comparing against
3001 * is relative to the current image filename (or absolute) */
3002 path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
3003 curr_bs->backing_file);
3005 if (!realpath(filename_tmp, backing_file_full)) {
3006 continue;
3009 if (strcmp(backing_file_full, filename_full) == 0) {
3010 retval = curr_bs->backing->bs;
3011 break;
3016 g_free(filename_full);
3017 g_free(backing_file_full);
3018 g_free(filename_tmp);
3019 return retval;
3022 int bdrv_get_backing_file_depth(BlockDriverState *bs)
3024 if (!bs->drv) {
3025 return 0;
3028 if (!bs->backing) {
3029 return 0;
3032 return 1 + bdrv_get_backing_file_depth(bs->backing->bs);
3035 void bdrv_init(void)
3037 module_call_init(MODULE_INIT_BLOCK);
3040 void bdrv_init_with_whitelist(void)
3042 use_bdrv_whitelist = 1;
3043 bdrv_init();
3046 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
3048 BdrvChild *child;
3049 Error *local_err = NULL;
3050 int ret;
3052 if (!bs->drv) {
3053 return;
3056 if (!(bs->open_flags & BDRV_O_INACTIVE)) {
3057 return;
3059 bs->open_flags &= ~BDRV_O_INACTIVE;
3061 if (bs->drv->bdrv_invalidate_cache) {
3062 bs->drv->bdrv_invalidate_cache(bs, &local_err);
3063 if (local_err) {
3064 bs->open_flags |= BDRV_O_INACTIVE;
3065 error_propagate(errp, local_err);
3066 return;
3070 QLIST_FOREACH(child, &bs->children, next) {
3071 bdrv_invalidate_cache(child->bs, &local_err);
3072 if (local_err) {
3073 bs->open_flags |= BDRV_O_INACTIVE;
3074 error_propagate(errp, local_err);
3075 return;
3079 ret = refresh_total_sectors(bs, bs->total_sectors);
3080 if (ret < 0) {
3081 bs->open_flags |= BDRV_O_INACTIVE;
3082 error_setg_errno(errp, -ret, "Could not refresh total sector count");
3083 return;
3087 void bdrv_invalidate_cache_all(Error **errp)
3089 BlockDriverState *bs;
3090 Error *local_err = NULL;
3091 BdrvNextIterator it;
3093 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3094 AioContext *aio_context = bdrv_get_aio_context(bs);
3096 aio_context_acquire(aio_context);
3097 bdrv_invalidate_cache(bs, &local_err);
3098 aio_context_release(aio_context);
3099 if (local_err) {
3100 error_propagate(errp, local_err);
3101 return;
3106 static int bdrv_inactivate_recurse(BlockDriverState *bs,
3107 bool setting_flag)
3109 BdrvChild *child;
3110 int ret;
3112 if (!setting_flag && bs->drv->bdrv_inactivate) {
3113 ret = bs->drv->bdrv_inactivate(bs);
3114 if (ret < 0) {
3115 return ret;
3119 QLIST_FOREACH(child, &bs->children, next) {
3120 ret = bdrv_inactivate_recurse(child->bs, setting_flag);
3121 if (ret < 0) {
3122 return ret;
3126 if (setting_flag) {
3127 bs->open_flags |= BDRV_O_INACTIVE;
3129 return 0;
3132 int bdrv_inactivate_all(void)
3134 BlockDriverState *bs = NULL;
3135 BdrvNextIterator it;
3136 int ret = 0;
3137 int pass;
3139 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3140 aio_context_acquire(bdrv_get_aio_context(bs));
3143 /* We do two passes of inactivation. The first pass calls to drivers'
3144 * .bdrv_inactivate callbacks recursively so all cache is flushed to disk;
3145 * the second pass sets the BDRV_O_INACTIVE flag so that no further write
3146 * is allowed. */
3147 for (pass = 0; pass < 2; pass++) {
3148 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3149 ret = bdrv_inactivate_recurse(bs, pass);
3150 if (ret < 0) {
3151 goto out;
3156 out:
3157 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3158 aio_context_release(bdrv_get_aio_context(bs));
3161 return ret;
3164 /**************************************************************/
3165 /* removable device support */
3168 * Return TRUE if the media is present
3170 bool bdrv_is_inserted(BlockDriverState *bs)
3172 BlockDriver *drv = bs->drv;
3173 BdrvChild *child;
3175 if (!drv) {
3176 return false;
3178 if (drv->bdrv_is_inserted) {
3179 return drv->bdrv_is_inserted(bs);
3181 QLIST_FOREACH(child, &bs->children, next) {
3182 if (!bdrv_is_inserted(child->bs)) {
3183 return false;
3186 return true;
3190 * Return whether the media changed since the last call to this
3191 * function, or -ENOTSUP if we don't know. Most drivers don't know.
3193 int bdrv_media_changed(BlockDriverState *bs)
3195 BlockDriver *drv = bs->drv;
3197 if (drv && drv->bdrv_media_changed) {
3198 return drv->bdrv_media_changed(bs);
3200 return -ENOTSUP;
3204 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
3206 void bdrv_eject(BlockDriverState *bs, bool eject_flag)
3208 BlockDriver *drv = bs->drv;
3209 const char *device_name;
3211 if (drv && drv->bdrv_eject) {
3212 drv->bdrv_eject(bs, eject_flag);
3215 device_name = bdrv_get_device_name(bs);
3216 if (device_name[0] != '\0') {
3217 qapi_event_send_device_tray_moved(device_name,
3218 eject_flag, &error_abort);
3223 * Lock or unlock the media (if it is locked, the user won't be able
3224 * to eject it manually).
3226 void bdrv_lock_medium(BlockDriverState *bs, bool locked)
3228 BlockDriver *drv = bs->drv;
3230 trace_bdrv_lock_medium(bs, locked);
3232 if (drv && drv->bdrv_lock_medium) {
3233 drv->bdrv_lock_medium(bs, locked);
3237 /* Get a reference to bs */
3238 void bdrv_ref(BlockDriverState *bs)
3240 bs->refcnt++;
3243 /* Release a previously grabbed reference to bs.
3244 * If after releasing, reference count is zero, the BlockDriverState is
3245 * deleted. */
3246 void bdrv_unref(BlockDriverState *bs)
3248 if (!bs) {
3249 return;
3251 assert(bs->refcnt > 0);
3252 if (--bs->refcnt == 0) {
3253 bdrv_delete(bs);
3257 struct BdrvOpBlocker {
3258 Error *reason;
3259 QLIST_ENTRY(BdrvOpBlocker) list;
3262 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp)
3264 BdrvOpBlocker *blocker;
3265 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
3266 if (!QLIST_EMPTY(&bs->op_blockers[op])) {
3267 blocker = QLIST_FIRST(&bs->op_blockers[op]);
3268 if (errp) {
3269 *errp = error_copy(blocker->reason);
3270 error_prepend(errp, "Node '%s' is busy: ",
3271 bdrv_get_device_or_node_name(bs));
3273 return true;
3275 return false;
3278 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason)
3280 BdrvOpBlocker *blocker;
3281 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
3283 blocker = g_new0(BdrvOpBlocker, 1);
3284 blocker->reason = reason;
3285 QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list);
3288 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason)
3290 BdrvOpBlocker *blocker, *next;
3291 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
3292 QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) {
3293 if (blocker->reason == reason) {
3294 QLIST_REMOVE(blocker, list);
3295 g_free(blocker);
3300 void bdrv_op_block_all(BlockDriverState *bs, Error *reason)
3302 int i;
3303 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
3304 bdrv_op_block(bs, i, reason);
3308 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason)
3310 int i;
3311 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
3312 bdrv_op_unblock(bs, i, reason);
3316 bool bdrv_op_blocker_is_empty(BlockDriverState *bs)
3318 int i;
3320 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
3321 if (!QLIST_EMPTY(&bs->op_blockers[i])) {
3322 return false;
3325 return true;
3328 void bdrv_img_create(const char *filename, const char *fmt,
3329 const char *base_filename, const char *base_fmt,
3330 char *options, uint64_t img_size, int flags,
3331 Error **errp, bool quiet)
3333 QemuOptsList *create_opts = NULL;
3334 QemuOpts *opts = NULL;
3335 const char *backing_fmt, *backing_file;
3336 int64_t size;
3337 BlockDriver *drv, *proto_drv;
3338 Error *local_err = NULL;
3339 int ret = 0;
3341 /* Find driver and parse its options */
3342 drv = bdrv_find_format(fmt);
3343 if (!drv) {
3344 error_setg(errp, "Unknown file format '%s'", fmt);
3345 return;
3348 proto_drv = bdrv_find_protocol(filename, true, errp);
3349 if (!proto_drv) {
3350 return;
3353 if (!drv->create_opts) {
3354 error_setg(errp, "Format driver '%s' does not support image creation",
3355 drv->format_name);
3356 return;
3359 if (!proto_drv->create_opts) {
3360 error_setg(errp, "Protocol driver '%s' does not support image creation",
3361 proto_drv->format_name);
3362 return;
3365 create_opts = qemu_opts_append(create_opts, drv->create_opts);
3366 create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
3368 /* Create parameter list with default values */
3369 opts = qemu_opts_create(create_opts, NULL, 0, &error_abort);
3370 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, img_size, &error_abort);
3372 /* Parse -o options */
3373 if (options) {
3374 qemu_opts_do_parse(opts, options, NULL, &local_err);
3375 if (local_err) {
3376 error_report_err(local_err);
3377 local_err = NULL;
3378 error_setg(errp, "Invalid options for file format '%s'", fmt);
3379 goto out;
3383 if (base_filename) {
3384 qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename, &local_err);
3385 if (local_err) {
3386 error_setg(errp, "Backing file not supported for file format '%s'",
3387 fmt);
3388 goto out;
3392 if (base_fmt) {
3393 qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt, &local_err);
3394 if (local_err) {
3395 error_setg(errp, "Backing file format not supported for file "
3396 "format '%s'", fmt);
3397 goto out;
3401 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
3402 if (backing_file) {
3403 if (!strcmp(filename, backing_file)) {
3404 error_setg(errp, "Error: Trying to create an image with the "
3405 "same filename as the backing file");
3406 goto out;
3410 backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
3412 // The size for the image must always be specified, with one exception:
3413 // If we are using a backing file, we can obtain the size from there
3414 size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
3415 if (size == -1) {
3416 if (backing_file) {
3417 BlockDriverState *bs;
3418 char *full_backing = g_new0(char, PATH_MAX);
3419 int64_t size;
3420 int back_flags;
3421 QDict *backing_options = NULL;
3423 bdrv_get_full_backing_filename_from_filename(filename, backing_file,
3424 full_backing, PATH_MAX,
3425 &local_err);
3426 if (local_err) {
3427 g_free(full_backing);
3428 goto out;
3431 /* backing files always opened read-only */
3432 back_flags = flags;
3433 back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
3435 if (backing_fmt) {
3436 backing_options = qdict_new();
3437 qdict_put(backing_options, "driver",
3438 qstring_from_str(backing_fmt));
3441 bs = bdrv_open(full_backing, NULL, backing_options, back_flags,
3442 &local_err);
3443 g_free(full_backing);
3444 if (!bs) {
3445 goto out;
3447 size = bdrv_getlength(bs);
3448 if (size < 0) {
3449 error_setg_errno(errp, -size, "Could not get size of '%s'",
3450 backing_file);
3451 bdrv_unref(bs);
3452 goto out;
3455 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort);
3457 bdrv_unref(bs);
3458 } else {
3459 error_setg(errp, "Image creation needs a size parameter");
3460 goto out;
3464 if (!quiet) {
3465 printf("Formatting '%s', fmt=%s ", filename, fmt);
3466 qemu_opts_print(opts, " ");
3467 puts("");
3470 ret = bdrv_create(drv, filename, opts, &local_err);
3472 if (ret == -EFBIG) {
3473 /* This is generally a better message than whatever the driver would
3474 * deliver (especially because of the cluster_size_hint), since that
3475 * is most probably not much different from "image too large". */
3476 const char *cluster_size_hint = "";
3477 if (qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 0)) {
3478 cluster_size_hint = " (try using a larger cluster size)";
3480 error_setg(errp, "The image size is too large for file format '%s'"
3481 "%s", fmt, cluster_size_hint);
3482 error_free(local_err);
3483 local_err = NULL;
3486 out:
3487 qemu_opts_del(opts);
3488 qemu_opts_free(create_opts);
3489 error_propagate(errp, local_err);
3492 AioContext *bdrv_get_aio_context(BlockDriverState *bs)
3494 return bs->aio_context;
3497 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban)
3499 QLIST_REMOVE(ban, list);
3500 g_free(ban);
3503 void bdrv_detach_aio_context(BlockDriverState *bs)
3505 BdrvAioNotifier *baf, *baf_tmp;
3506 BdrvChild *child;
3508 if (!bs->drv) {
3509 return;
3512 assert(!bs->walking_aio_notifiers);
3513 bs->walking_aio_notifiers = true;
3514 QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) {
3515 if (baf->deleted) {
3516 bdrv_do_remove_aio_context_notifier(baf);
3517 } else {
3518 baf->detach_aio_context(baf->opaque);
3521 /* Never mind iterating again to check for ->deleted. bdrv_close() will
3522 * remove remaining aio notifiers if we aren't called again.
3524 bs->walking_aio_notifiers = false;
3526 if (bs->drv->bdrv_detach_aio_context) {
3527 bs->drv->bdrv_detach_aio_context(bs);
3529 QLIST_FOREACH(child, &bs->children, next) {
3530 bdrv_detach_aio_context(child->bs);
3533 bs->aio_context = NULL;
3536 void bdrv_attach_aio_context(BlockDriverState *bs,
3537 AioContext *new_context)
3539 BdrvAioNotifier *ban, *ban_tmp;
3540 BdrvChild *child;
3542 if (!bs->drv) {
3543 return;
3546 bs->aio_context = new_context;
3548 QLIST_FOREACH(child, &bs->children, next) {
3549 bdrv_attach_aio_context(child->bs, new_context);
3551 if (bs->drv->bdrv_attach_aio_context) {
3552 bs->drv->bdrv_attach_aio_context(bs, new_context);
3555 assert(!bs->walking_aio_notifiers);
3556 bs->walking_aio_notifiers = true;
3557 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_tmp) {
3558 if (ban->deleted) {
3559 bdrv_do_remove_aio_context_notifier(ban);
3560 } else {
3561 ban->attached_aio_context(new_context, ban->opaque);
3564 bs->walking_aio_notifiers = false;
3567 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
3569 bdrv_drain(bs); /* ensure there are no in-flight requests */
3571 bdrv_detach_aio_context(bs);
3573 /* This function executes in the old AioContext so acquire the new one in
3574 * case it runs in a different thread.
3576 aio_context_acquire(new_context);
3577 bdrv_attach_aio_context(bs, new_context);
3578 aio_context_release(new_context);
3581 void bdrv_add_aio_context_notifier(BlockDriverState *bs,
3582 void (*attached_aio_context)(AioContext *new_context, void *opaque),
3583 void (*detach_aio_context)(void *opaque), void *opaque)
3585 BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1);
3586 *ban = (BdrvAioNotifier){
3587 .attached_aio_context = attached_aio_context,
3588 .detach_aio_context = detach_aio_context,
3589 .opaque = opaque
3592 QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list);
3595 void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
3596 void (*attached_aio_context)(AioContext *,
3597 void *),
3598 void (*detach_aio_context)(void *),
3599 void *opaque)
3601 BdrvAioNotifier *ban, *ban_next;
3603 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
3604 if (ban->attached_aio_context == attached_aio_context &&
3605 ban->detach_aio_context == detach_aio_context &&
3606 ban->opaque == opaque &&
3607 ban->deleted == false)
3609 if (bs->walking_aio_notifiers) {
3610 ban->deleted = true;
3611 } else {
3612 bdrv_do_remove_aio_context_notifier(ban);
3614 return;
3618 abort();
3621 int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts,
3622 BlockDriverAmendStatusCB *status_cb, void *cb_opaque)
3624 if (!bs->drv->bdrv_amend_options) {
3625 return -ENOTSUP;
3627 return bs->drv->bdrv_amend_options(bs, opts, status_cb, cb_opaque);
3630 /* This function will be called by the bdrv_recurse_is_first_non_filter method
3631 * of block filter and by bdrv_is_first_non_filter.
3632 * It is used to test if the given bs is the candidate or recurse more in the
3633 * node graph.
3635 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
3636 BlockDriverState *candidate)
3638 /* return false if basic checks fails */
3639 if (!bs || !bs->drv) {
3640 return false;
3643 /* the code reached a non block filter driver -> check if the bs is
3644 * the same as the candidate. It's the recursion termination condition.
3646 if (!bs->drv->is_filter) {
3647 return bs == candidate;
3649 /* Down this path the driver is a block filter driver */
3651 /* If the block filter recursion method is defined use it to recurse down
3652 * the node graph.
3654 if (bs->drv->bdrv_recurse_is_first_non_filter) {
3655 return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate);
3658 /* the driver is a block filter but don't allow to recurse -> return false
3660 return false;
3663 /* This function checks if the candidate is the first non filter bs down it's
3664 * bs chain. Since we don't have pointers to parents it explore all bs chains
3665 * from the top. Some filters can choose not to pass down the recursion.
3667 bool bdrv_is_first_non_filter(BlockDriverState *candidate)
3669 BlockDriverState *bs;
3670 BdrvNextIterator it;
3672 /* walk down the bs forest recursively */
3673 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
3674 bool perm;
3676 /* try to recurse in this top level bs */
3677 perm = bdrv_recurse_is_first_non_filter(bs, candidate);
3679 /* candidate is the first non filter */
3680 if (perm) {
3681 return true;
3685 return false;
3688 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
3689 const char *node_name, Error **errp)
3691 BlockDriverState *to_replace_bs = bdrv_find_node(node_name);
3692 AioContext *aio_context;
3694 if (!to_replace_bs) {
3695 error_setg(errp, "Node name '%s' not found", node_name);
3696 return NULL;
3699 aio_context = bdrv_get_aio_context(to_replace_bs);
3700 aio_context_acquire(aio_context);
3702 if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) {
3703 to_replace_bs = NULL;
3704 goto out;
3707 /* We don't want arbitrary node of the BDS chain to be replaced only the top
3708 * most non filter in order to prevent data corruption.
3709 * Another benefit is that this tests exclude backing files which are
3710 * blocked by the backing blockers.
3712 if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) {
3713 error_setg(errp, "Only top most non filter can be replaced");
3714 to_replace_bs = NULL;
3715 goto out;
3718 out:
3719 aio_context_release(aio_context);
3720 return to_replace_bs;
3723 static bool append_open_options(QDict *d, BlockDriverState *bs)
3725 const QDictEntry *entry;
3726 QemuOptDesc *desc;
3727 BdrvChild *child;
3728 bool found_any = false;
3729 const char *p;
3731 for (entry = qdict_first(bs->options); entry;
3732 entry = qdict_next(bs->options, entry))
3734 /* Exclude options for children */
3735 QLIST_FOREACH(child, &bs->children, next) {
3736 if (strstart(qdict_entry_key(entry), child->name, &p)
3737 && (!*p || *p == '.'))
3739 break;
3742 if (child) {
3743 continue;
3746 /* And exclude all non-driver-specific options */
3747 for (desc = bdrv_runtime_opts.desc; desc->name; desc++) {
3748 if (!strcmp(qdict_entry_key(entry), desc->name)) {
3749 break;
3752 if (desc->name) {
3753 continue;
3756 qobject_incref(qdict_entry_value(entry));
3757 qdict_put_obj(d, qdict_entry_key(entry), qdict_entry_value(entry));
3758 found_any = true;
3761 return found_any;
3764 /* Updates the following BDS fields:
3765 * - exact_filename: A filename which may be used for opening a block device
3766 * which (mostly) equals the given BDS (even without any
3767 * other options; so reading and writing must return the same
3768 * results, but caching etc. may be different)
3769 * - full_open_options: Options which, when given when opening a block device
3770 * (without a filename), result in a BDS (mostly)
3771 * equalling the given one
3772 * - filename: If exact_filename is set, it is copied here. Otherwise,
3773 * full_open_options is converted to a JSON object, prefixed with
3774 * "json:" (for use through the JSON pseudo protocol) and put here.
3776 void bdrv_refresh_filename(BlockDriverState *bs)
3778 BlockDriver *drv = bs->drv;
3779 QDict *opts;
3781 if (!drv) {
3782 return;
3785 /* This BDS's file name will most probably depend on its file's name, so
3786 * refresh that first */
3787 if (bs->file) {
3788 bdrv_refresh_filename(bs->file->bs);
3791 if (drv->bdrv_refresh_filename) {
3792 /* Obsolete information is of no use here, so drop the old file name
3793 * information before refreshing it */
3794 bs->exact_filename[0] = '\0';
3795 if (bs->full_open_options) {
3796 QDECREF(bs->full_open_options);
3797 bs->full_open_options = NULL;
3800 opts = qdict_new();
3801 append_open_options(opts, bs);
3802 drv->bdrv_refresh_filename(bs, opts);
3803 QDECREF(opts);
3804 } else if (bs->file) {
3805 /* Try to reconstruct valid information from the underlying file */
3806 bool has_open_options;
3808 bs->exact_filename[0] = '\0';
3809 if (bs->full_open_options) {
3810 QDECREF(bs->full_open_options);
3811 bs->full_open_options = NULL;
3814 opts = qdict_new();
3815 has_open_options = append_open_options(opts, bs);
3817 /* If no specific options have been given for this BDS, the filename of
3818 * the underlying file should suffice for this one as well */
3819 if (bs->file->bs->exact_filename[0] && !has_open_options) {
3820 strcpy(bs->exact_filename, bs->file->bs->exact_filename);
3822 /* Reconstructing the full options QDict is simple for most format block
3823 * drivers, as long as the full options are known for the underlying
3824 * file BDS. The full options QDict of that file BDS should somehow
3825 * contain a representation of the filename, therefore the following
3826 * suffices without querying the (exact_)filename of this BDS. */
3827 if (bs->file->bs->full_open_options) {
3828 qdict_put_obj(opts, "driver",
3829 QOBJECT(qstring_from_str(drv->format_name)));
3830 QINCREF(bs->file->bs->full_open_options);
3831 qdict_put_obj(opts, "file",
3832 QOBJECT(bs->file->bs->full_open_options));
3834 bs->full_open_options = opts;
3835 } else {
3836 QDECREF(opts);
3838 } else if (!bs->full_open_options && qdict_size(bs->options)) {
3839 /* There is no underlying file BDS (at least referenced by BDS.file),
3840 * so the full options QDict should be equal to the options given
3841 * specifically for this block device when it was opened (plus the
3842 * driver specification).
3843 * Because those options don't change, there is no need to update
3844 * full_open_options when it's already set. */
3846 opts = qdict_new();
3847 append_open_options(opts, bs);
3848 qdict_put_obj(opts, "driver",
3849 QOBJECT(qstring_from_str(drv->format_name)));
3851 if (bs->exact_filename[0]) {
3852 /* This may not work for all block protocol drivers (some may
3853 * require this filename to be parsed), but we have to find some
3854 * default solution here, so just include it. If some block driver
3855 * does not support pure options without any filename at all or
3856 * needs some special format of the options QDict, it needs to
3857 * implement the driver-specific bdrv_refresh_filename() function.
3859 qdict_put_obj(opts, "filename",
3860 QOBJECT(qstring_from_str(bs->exact_filename)));
3863 bs->full_open_options = opts;
3866 if (bs->exact_filename[0]) {
3867 pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename);
3868 } else if (bs->full_open_options) {
3869 QString *json = qobject_to_json(QOBJECT(bs->full_open_options));
3870 snprintf(bs->filename, sizeof(bs->filename), "json:%s",
3871 qstring_get_str(json));
3872 QDECREF(json);
3877 * Hot add/remove a BDS's child. So the user can take a child offline when
3878 * it is broken and take a new child online
3880 void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs,
3881 Error **errp)
3884 if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) {
3885 error_setg(errp, "The node %s does not support adding a child",
3886 bdrv_get_device_or_node_name(parent_bs));
3887 return;
3890 if (!QLIST_EMPTY(&child_bs->parents)) {
3891 error_setg(errp, "The node %s already has a parent",
3892 child_bs->node_name);
3893 return;
3896 parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp);
3899 void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp)
3901 BdrvChild *tmp;
3903 if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) {
3904 error_setg(errp, "The node %s does not support removing a child",
3905 bdrv_get_device_or_node_name(parent_bs));
3906 return;
3909 QLIST_FOREACH(tmp, &parent_bs->children, next) {
3910 if (tmp == child) {
3911 break;
3915 if (!tmp) {
3916 error_setg(errp, "The node %s does not have a child named %s",
3917 bdrv_get_device_or_node_name(parent_bs),
3918 bdrv_get_device_or_node_name(child->bs));
3919 return;
3922 parent_bs->drv->bdrv_del_child(parent_bs, child, errp);