block: avoid recursive AioContext acquire in bdrv_inactivate_all()
[qemu/ar7.git] / block.c
blob1c37ce4554b03ed2e914159013118531431cbfbd
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 "block/trace.h"
26 #include "block/block_int.h"
27 #include "block/blockjob.h"
28 #include "block/nbd.h"
29 #include "qemu/error-report.h"
30 #include "module_block.h"
31 #include "qemu/module.h"
32 #include "qapi/qmp/qerror.h"
33 #include "qapi/qmp/qbool.h"
34 #include "qapi/qmp/qjson.h"
35 #include "sysemu/block-backend.h"
36 #include "sysemu/sysemu.h"
37 #include "qemu/notify.h"
38 #include "qemu/coroutine.h"
39 #include "block/qapi.h"
40 #include "qmp-commands.h"
41 #include "qemu/timer.h"
42 #include "qapi-event.h"
43 #include "qemu/cutils.h"
44 #include "qemu/id.h"
46 #ifdef CONFIG_BSD
47 #include <sys/ioctl.h>
48 #include <sys/queue.h>
49 #ifndef __DragonFly__
50 #include <sys/disk.h>
51 #endif
52 #endif
54 #ifdef _WIN32
55 #include <windows.h>
56 #endif
58 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
60 static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states =
61 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states);
63 static QTAILQ_HEAD(, BlockDriverState) all_bdrv_states =
64 QTAILQ_HEAD_INITIALIZER(all_bdrv_states);
66 static QLIST_HEAD(, BlockDriver) bdrv_drivers =
67 QLIST_HEAD_INITIALIZER(bdrv_drivers);
69 static BlockDriverState *bdrv_open_inherit(const char *filename,
70 const char *reference,
71 QDict *options, int flags,
72 BlockDriverState *parent,
73 const BdrvChildRole *child_role,
74 Error **errp);
76 /* If non-zero, use only whitelisted block drivers */
77 static int use_bdrv_whitelist;
79 #ifdef _WIN32
80 static int is_windows_drive_prefix(const char *filename)
82 return (((filename[0] >= 'a' && filename[0] <= 'z') ||
83 (filename[0] >= 'A' && filename[0] <= 'Z')) &&
84 filename[1] == ':');
87 int is_windows_drive(const char *filename)
89 if (is_windows_drive_prefix(filename) &&
90 filename[2] == '\0')
91 return 1;
92 if (strstart(filename, "\\\\.\\", NULL) ||
93 strstart(filename, "//./", NULL))
94 return 1;
95 return 0;
97 #endif
99 size_t bdrv_opt_mem_align(BlockDriverState *bs)
101 if (!bs || !bs->drv) {
102 /* page size or 4k (hdd sector size) should be on the safe side */
103 return MAX(4096, getpagesize());
106 return bs->bl.opt_mem_alignment;
109 size_t bdrv_min_mem_align(BlockDriverState *bs)
111 if (!bs || !bs->drv) {
112 /* page size or 4k (hdd sector size) should be on the safe side */
113 return MAX(4096, getpagesize());
116 return bs->bl.min_mem_alignment;
119 /* check if the path starts with "<protocol>:" */
120 int path_has_protocol(const char *path)
122 const char *p;
124 #ifdef _WIN32
125 if (is_windows_drive(path) ||
126 is_windows_drive_prefix(path)) {
127 return 0;
129 p = path + strcspn(path, ":/\\");
130 #else
131 p = path + strcspn(path, ":/");
132 #endif
134 return *p == ':';
137 int path_is_absolute(const char *path)
139 #ifdef _WIN32
140 /* specific case for names like: "\\.\d:" */
141 if (is_windows_drive(path) || is_windows_drive_prefix(path)) {
142 return 1;
144 return (*path == '/' || *path == '\\');
145 #else
146 return (*path == '/');
147 #endif
150 /* if filename is absolute, just copy it to dest. Otherwise, build a
151 path to it by considering it is relative to base_path. URL are
152 supported. */
153 void path_combine(char *dest, int dest_size,
154 const char *base_path,
155 const char *filename)
157 const char *p, *p1;
158 int len;
160 if (dest_size <= 0)
161 return;
162 if (path_is_absolute(filename)) {
163 pstrcpy(dest, dest_size, filename);
164 } else {
165 const char *protocol_stripped = NULL;
167 if (path_has_protocol(base_path)) {
168 protocol_stripped = strchr(base_path, ':');
169 if (protocol_stripped) {
170 protocol_stripped++;
173 p = protocol_stripped ?: base_path;
175 p1 = strrchr(base_path, '/');
176 #ifdef _WIN32
178 const char *p2;
179 p2 = strrchr(base_path, '\\');
180 if (!p1 || p2 > p1)
181 p1 = p2;
183 #endif
184 if (p1)
185 p1++;
186 else
187 p1 = base_path;
188 if (p1 > p)
189 p = p1;
190 len = p - base_path;
191 if (len > dest_size - 1)
192 len = dest_size - 1;
193 memcpy(dest, base_path, len);
194 dest[len] = '\0';
195 pstrcat(dest, dest_size, filename);
200 * Helper function for bdrv_parse_filename() implementations to remove optional
201 * protocol prefixes (especially "file:") from a filename and for putting the
202 * stripped filename into the options QDict if there is such a prefix.
204 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix,
205 QDict *options)
207 if (strstart(filename, prefix, &filename)) {
208 /* Stripping the explicit protocol prefix may result in a protocol
209 * prefix being (wrongly) detected (if the filename contains a colon) */
210 if (path_has_protocol(filename)) {
211 QString *fat_filename;
213 /* This means there is some colon before the first slash; therefore,
214 * this cannot be an absolute path */
215 assert(!path_is_absolute(filename));
217 /* And we can thus fix the protocol detection issue by prefixing it
218 * by "./" */
219 fat_filename = qstring_from_str("./");
220 qstring_append(fat_filename, filename);
222 assert(!path_has_protocol(qstring_get_str(fat_filename)));
224 qdict_put(options, "filename", fat_filename);
225 } else {
226 /* If no protocol prefix was detected, we can use the shortened
227 * filename as-is */
228 qdict_put_str(options, "filename", filename);
234 /* Returns whether the image file is opened as read-only. Note that this can
235 * return false and writing to the image file is still not possible because the
236 * image is inactivated. */
237 bool bdrv_is_read_only(BlockDriverState *bs)
239 return bs->read_only;
242 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
243 bool ignore_allow_rdw, Error **errp)
245 /* Do not set read_only if copy_on_read is enabled */
246 if (bs->copy_on_read && read_only) {
247 error_setg(errp, "Can't set node '%s' to r/o with copy-on-read enabled",
248 bdrv_get_device_or_node_name(bs));
249 return -EINVAL;
252 /* Do not clear read_only if it is prohibited */
253 if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR) &&
254 !ignore_allow_rdw)
256 error_setg(errp, "Node '%s' is read only",
257 bdrv_get_device_or_node_name(bs));
258 return -EPERM;
261 return 0;
264 /* TODO Remove (deprecated since 2.11)
265 * Block drivers are not supposed to automatically change bs->read_only.
266 * Instead, they should just check whether they can provide what the user
267 * explicitly requested and error out if read-write is requested, but they can
268 * only provide read-only access. */
269 int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
271 int ret = 0;
273 ret = bdrv_can_set_read_only(bs, read_only, false, errp);
274 if (ret < 0) {
275 return ret;
278 bs->read_only = read_only;
279 return 0;
282 void bdrv_get_full_backing_filename_from_filename(const char *backed,
283 const char *backing,
284 char *dest, size_t sz,
285 Error **errp)
287 if (backing[0] == '\0' || path_has_protocol(backing) ||
288 path_is_absolute(backing))
290 pstrcpy(dest, sz, backing);
291 } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) {
292 error_setg(errp, "Cannot use relative backing file names for '%s'",
293 backed);
294 } else {
295 path_combine(dest, sz, backed, backing);
299 void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz,
300 Error **errp)
302 char *backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename;
304 bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file,
305 dest, sz, errp);
308 void bdrv_register(BlockDriver *bdrv)
310 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list);
313 BlockDriverState *bdrv_new(void)
315 BlockDriverState *bs;
316 int i;
318 bs = g_new0(BlockDriverState, 1);
319 QLIST_INIT(&bs->dirty_bitmaps);
320 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
321 QLIST_INIT(&bs->op_blockers[i]);
323 notifier_with_return_list_init(&bs->before_write_notifiers);
324 qemu_co_mutex_init(&bs->reqs_lock);
325 qemu_mutex_init(&bs->dirty_bitmap_mutex);
326 bs->refcnt = 1;
327 bs->aio_context = qemu_get_aio_context();
329 qemu_co_queue_init(&bs->flush_queue);
331 QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list);
333 return bs;
336 static BlockDriver *bdrv_do_find_format(const char *format_name)
338 BlockDriver *drv1;
340 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
341 if (!strcmp(drv1->format_name, format_name)) {
342 return drv1;
346 return NULL;
349 BlockDriver *bdrv_find_format(const char *format_name)
351 BlockDriver *drv1;
352 int i;
354 drv1 = bdrv_do_find_format(format_name);
355 if (drv1) {
356 return drv1;
359 /* The driver isn't registered, maybe we need to load a module */
360 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
361 if (!strcmp(block_driver_modules[i].format_name, format_name)) {
362 block_module_load_one(block_driver_modules[i].library_name);
363 break;
367 return bdrv_do_find_format(format_name);
370 static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
372 static const char *whitelist_rw[] = {
373 CONFIG_BDRV_RW_WHITELIST
375 static const char *whitelist_ro[] = {
376 CONFIG_BDRV_RO_WHITELIST
378 const char **p;
380 if (!whitelist_rw[0] && !whitelist_ro[0]) {
381 return 1; /* no whitelist, anything goes */
384 for (p = whitelist_rw; *p; p++) {
385 if (!strcmp(drv->format_name, *p)) {
386 return 1;
389 if (read_only) {
390 for (p = whitelist_ro; *p; p++) {
391 if (!strcmp(drv->format_name, *p)) {
392 return 1;
396 return 0;
399 bool bdrv_uses_whitelist(void)
401 return use_bdrv_whitelist;
404 typedef struct CreateCo {
405 BlockDriver *drv;
406 char *filename;
407 QemuOpts *opts;
408 int ret;
409 Error *err;
410 } CreateCo;
412 static void coroutine_fn bdrv_create_co_entry(void *opaque)
414 Error *local_err = NULL;
415 int ret;
417 CreateCo *cco = opaque;
418 assert(cco->drv);
420 ret = cco->drv->bdrv_create(cco->filename, cco->opts, &local_err);
421 error_propagate(&cco->err, local_err);
422 cco->ret = ret;
425 int bdrv_create(BlockDriver *drv, const char* filename,
426 QemuOpts *opts, Error **errp)
428 int ret;
430 Coroutine *co;
431 CreateCo cco = {
432 .drv = drv,
433 .filename = g_strdup(filename),
434 .opts = opts,
435 .ret = NOT_DONE,
436 .err = NULL,
439 if (!drv->bdrv_create) {
440 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name);
441 ret = -ENOTSUP;
442 goto out;
445 if (qemu_in_coroutine()) {
446 /* Fast-path if already in coroutine context */
447 bdrv_create_co_entry(&cco);
448 } else {
449 co = qemu_coroutine_create(bdrv_create_co_entry, &cco);
450 qemu_coroutine_enter(co);
451 while (cco.ret == NOT_DONE) {
452 aio_poll(qemu_get_aio_context(), true);
456 ret = cco.ret;
457 if (ret < 0) {
458 if (cco.err) {
459 error_propagate(errp, cco.err);
460 } else {
461 error_setg_errno(errp, -ret, "Could not create image");
465 out:
466 g_free(cco.filename);
467 return ret;
470 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
472 BlockDriver *drv;
473 Error *local_err = NULL;
474 int ret;
476 drv = bdrv_find_protocol(filename, true, errp);
477 if (drv == NULL) {
478 return -ENOENT;
481 ret = bdrv_create(drv, filename, opts, &local_err);
482 error_propagate(errp, local_err);
483 return ret;
487 * Try to get @bs's logical and physical block size.
488 * On success, store them in @bsz struct and return 0.
489 * On failure return -errno.
490 * @bs must not be empty.
492 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
494 BlockDriver *drv = bs->drv;
496 if (drv && drv->bdrv_probe_blocksizes) {
497 return drv->bdrv_probe_blocksizes(bs, bsz);
498 } else if (drv && drv->is_filter && bs->file) {
499 return bdrv_probe_blocksizes(bs->file->bs, bsz);
502 return -ENOTSUP;
506 * Try to get @bs's geometry (cyls, heads, sectors).
507 * On success, store them in @geo struct and return 0.
508 * On failure return -errno.
509 * @bs must not be empty.
511 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
513 BlockDriver *drv = bs->drv;
515 if (drv && drv->bdrv_probe_geometry) {
516 return drv->bdrv_probe_geometry(bs, geo);
517 } else if (drv && drv->is_filter && bs->file) {
518 return bdrv_probe_geometry(bs->file->bs, geo);
521 return -ENOTSUP;
525 * Create a uniquely-named empty temporary file.
526 * Return 0 upon success, otherwise a negative errno value.
528 int get_tmp_filename(char *filename, int size)
530 #ifdef _WIN32
531 char temp_dir[MAX_PATH];
532 /* GetTempFileName requires that its output buffer (4th param)
533 have length MAX_PATH or greater. */
534 assert(size >= MAX_PATH);
535 return (GetTempPath(MAX_PATH, temp_dir)
536 && GetTempFileName(temp_dir, "qem", 0, filename)
537 ? 0 : -GetLastError());
538 #else
539 int fd;
540 const char *tmpdir;
541 tmpdir = getenv("TMPDIR");
542 if (!tmpdir) {
543 tmpdir = "/var/tmp";
545 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) {
546 return -EOVERFLOW;
548 fd = mkstemp(filename);
549 if (fd < 0) {
550 return -errno;
552 if (close(fd) != 0) {
553 unlink(filename);
554 return -errno;
556 return 0;
557 #endif
561 * Detect host devices. By convention, /dev/cdrom[N] is always
562 * recognized as a host CDROM.
564 static BlockDriver *find_hdev_driver(const char *filename)
566 int score_max = 0, score;
567 BlockDriver *drv = NULL, *d;
569 QLIST_FOREACH(d, &bdrv_drivers, list) {
570 if (d->bdrv_probe_device) {
571 score = d->bdrv_probe_device(filename);
572 if (score > score_max) {
573 score_max = score;
574 drv = d;
579 return drv;
582 static BlockDriver *bdrv_do_find_protocol(const char *protocol)
584 BlockDriver *drv1;
586 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
587 if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) {
588 return drv1;
592 return NULL;
595 BlockDriver *bdrv_find_protocol(const char *filename,
596 bool allow_protocol_prefix,
597 Error **errp)
599 BlockDriver *drv1;
600 char protocol[128];
601 int len;
602 const char *p;
603 int i;
605 /* TODO Drivers without bdrv_file_open must be specified explicitly */
608 * XXX(hch): we really should not let host device detection
609 * override an explicit protocol specification, but moving this
610 * later breaks access to device names with colons in them.
611 * Thanks to the brain-dead persistent naming schemes on udev-
612 * based Linux systems those actually are quite common.
614 drv1 = find_hdev_driver(filename);
615 if (drv1) {
616 return drv1;
619 if (!path_has_protocol(filename) || !allow_protocol_prefix) {
620 return &bdrv_file;
623 p = strchr(filename, ':');
624 assert(p != NULL);
625 len = p - filename;
626 if (len > sizeof(protocol) - 1)
627 len = sizeof(protocol) - 1;
628 memcpy(protocol, filename, len);
629 protocol[len] = '\0';
631 drv1 = bdrv_do_find_protocol(protocol);
632 if (drv1) {
633 return drv1;
636 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
637 if (block_driver_modules[i].protocol_name &&
638 !strcmp(block_driver_modules[i].protocol_name, protocol)) {
639 block_module_load_one(block_driver_modules[i].library_name);
640 break;
644 drv1 = bdrv_do_find_protocol(protocol);
645 if (!drv1) {
646 error_setg(errp, "Unknown protocol '%s'", protocol);
648 return drv1;
652 * Guess image format by probing its contents.
653 * This is not a good idea when your image is raw (CVE-2008-2004), but
654 * we do it anyway for backward compatibility.
656 * @buf contains the image's first @buf_size bytes.
657 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
658 * but can be smaller if the image file is smaller)
659 * @filename is its filename.
661 * For all block drivers, call the bdrv_probe() method to get its
662 * probing score.
663 * Return the first block driver with the highest probing score.
665 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
666 const char *filename)
668 int score_max = 0, score;
669 BlockDriver *drv = NULL, *d;
671 QLIST_FOREACH(d, &bdrv_drivers, list) {
672 if (d->bdrv_probe) {
673 score = d->bdrv_probe(buf, buf_size, filename);
674 if (score > score_max) {
675 score_max = score;
676 drv = d;
681 return drv;
684 static int find_image_format(BlockBackend *file, const char *filename,
685 BlockDriver **pdrv, Error **errp)
687 BlockDriver *drv;
688 uint8_t buf[BLOCK_PROBE_BUF_SIZE];
689 int ret = 0;
691 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
692 if (blk_is_sg(file) || !blk_is_inserted(file) || blk_getlength(file) == 0) {
693 *pdrv = &bdrv_raw;
694 return ret;
697 ret = blk_pread(file, 0, buf, sizeof(buf));
698 if (ret < 0) {
699 error_setg_errno(errp, -ret, "Could not read image for determining its "
700 "format");
701 *pdrv = NULL;
702 return ret;
705 drv = bdrv_probe_all(buf, ret, filename);
706 if (!drv) {
707 error_setg(errp, "Could not determine image format: No compatible "
708 "driver found");
709 ret = -ENOENT;
711 *pdrv = drv;
712 return ret;
716 * Set the current 'total_sectors' value
717 * Return 0 on success, -errno on error.
719 static int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
721 BlockDriver *drv = bs->drv;
723 if (!drv) {
724 return -ENOMEDIUM;
727 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
728 if (bdrv_is_sg(bs))
729 return 0;
731 /* query actual device if possible, otherwise just trust the hint */
732 if (drv->bdrv_getlength) {
733 int64_t length = drv->bdrv_getlength(bs);
734 if (length < 0) {
735 return length;
737 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE);
740 bs->total_sectors = hint;
741 return 0;
745 * Combines a QDict of new block driver @options with any missing options taken
746 * from @old_options, so that leaving out an option defaults to its old value.
748 static void bdrv_join_options(BlockDriverState *bs, QDict *options,
749 QDict *old_options)
751 if (bs->drv && bs->drv->bdrv_join_options) {
752 bs->drv->bdrv_join_options(options, old_options);
753 } else {
754 qdict_join(options, old_options, false);
759 * Set open flags for a given discard mode
761 * Return 0 on success, -1 if the discard mode was invalid.
763 int bdrv_parse_discard_flags(const char *mode, int *flags)
765 *flags &= ~BDRV_O_UNMAP;
767 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) {
768 /* do nothing */
769 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) {
770 *flags |= BDRV_O_UNMAP;
771 } else {
772 return -1;
775 return 0;
779 * Set open flags for a given cache mode
781 * Return 0 on success, -1 if the cache mode was invalid.
783 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough)
785 *flags &= ~BDRV_O_CACHE_MASK;
787 if (!strcmp(mode, "off") || !strcmp(mode, "none")) {
788 *writethrough = false;
789 *flags |= BDRV_O_NOCACHE;
790 } else if (!strcmp(mode, "directsync")) {
791 *writethrough = true;
792 *flags |= BDRV_O_NOCACHE;
793 } else if (!strcmp(mode, "writeback")) {
794 *writethrough = false;
795 } else if (!strcmp(mode, "unsafe")) {
796 *writethrough = false;
797 *flags |= BDRV_O_NO_FLUSH;
798 } else if (!strcmp(mode, "writethrough")) {
799 *writethrough = true;
800 } else {
801 return -1;
804 return 0;
807 static char *bdrv_child_get_parent_desc(BdrvChild *c)
809 BlockDriverState *parent = c->opaque;
810 return g_strdup(bdrv_get_device_or_node_name(parent));
813 static void bdrv_child_cb_drained_begin(BdrvChild *child)
815 BlockDriverState *bs = child->opaque;
816 bdrv_drained_begin(bs);
819 static void bdrv_child_cb_drained_end(BdrvChild *child)
821 BlockDriverState *bs = child->opaque;
822 bdrv_drained_end(bs);
825 static int bdrv_child_cb_inactivate(BdrvChild *child)
827 BlockDriverState *bs = child->opaque;
828 assert(bs->open_flags & BDRV_O_INACTIVE);
829 return 0;
833 * Returns the options and flags that a temporary snapshot should get, based on
834 * the originally requested flags (the originally requested image will have
835 * flags like a backing file)
837 static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
838 int parent_flags, QDict *parent_options)
840 *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY;
842 /* For temporary files, unconditional cache=unsafe is fine */
843 qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off");
844 qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
846 /* Copy the read-only option from the parent */
847 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
849 /* aio=native doesn't work for cache.direct=off, so disable it for the
850 * temporary snapshot */
851 *child_flags &= ~BDRV_O_NATIVE_AIO;
855 * Returns the options and flags that bs->file should get if a protocol driver
856 * is expected, based on the given options and flags for the parent BDS
858 static void bdrv_inherited_options(int *child_flags, QDict *child_options,
859 int parent_flags, QDict *parent_options)
861 int flags = parent_flags;
863 /* Enable protocol handling, disable format probing for bs->file */
864 flags |= BDRV_O_PROTOCOL;
866 /* If the cache mode isn't explicitly set, inherit direct and no-flush from
867 * the parent. */
868 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
869 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
870 qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
872 /* Inherit the read-only option from the parent if it's not set */
873 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
875 /* Our block drivers take care to send flushes and respect unmap policy,
876 * so we can default to enable both on lower layers regardless of the
877 * corresponding parent options. */
878 qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap");
880 /* Clear flags that only apply to the top layer */
881 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ |
882 BDRV_O_NO_IO);
884 *child_flags = flags;
887 const BdrvChildRole child_file = {
888 .get_parent_desc = bdrv_child_get_parent_desc,
889 .inherit_options = bdrv_inherited_options,
890 .drained_begin = bdrv_child_cb_drained_begin,
891 .drained_end = bdrv_child_cb_drained_end,
892 .inactivate = bdrv_child_cb_inactivate,
896 * Returns the options and flags that bs->file should get if the use of formats
897 * (and not only protocols) is permitted for it, based on the given options and
898 * flags for the parent BDS
900 static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options,
901 int parent_flags, QDict *parent_options)
903 child_file.inherit_options(child_flags, child_options,
904 parent_flags, parent_options);
906 *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO);
909 const BdrvChildRole child_format = {
910 .get_parent_desc = bdrv_child_get_parent_desc,
911 .inherit_options = bdrv_inherited_fmt_options,
912 .drained_begin = bdrv_child_cb_drained_begin,
913 .drained_end = bdrv_child_cb_drained_end,
914 .inactivate = bdrv_child_cb_inactivate,
917 static void bdrv_backing_attach(BdrvChild *c)
919 BlockDriverState *parent = c->opaque;
920 BlockDriverState *backing_hd = c->bs;
922 assert(!parent->backing_blocker);
923 error_setg(&parent->backing_blocker,
924 "node is used as backing hd of '%s'",
925 bdrv_get_device_or_node_name(parent));
927 parent->open_flags &= ~BDRV_O_NO_BACKING;
928 pstrcpy(parent->backing_file, sizeof(parent->backing_file),
929 backing_hd->filename);
930 pstrcpy(parent->backing_format, sizeof(parent->backing_format),
931 backing_hd->drv ? backing_hd->drv->format_name : "");
933 bdrv_op_block_all(backing_hd, parent->backing_blocker);
934 /* Otherwise we won't be able to commit or stream */
935 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,
936 parent->backing_blocker);
937 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_STREAM,
938 parent->backing_blocker);
940 * We do backup in 3 ways:
941 * 1. drive backup
942 * The target bs is new opened, and the source is top BDS
943 * 2. blockdev backup
944 * Both the source and the target are top BDSes.
945 * 3. internal backup(used for block replication)
946 * Both the source and the target are backing file
948 * In case 1 and 2, neither the source nor the target is the backing file.
949 * In case 3, we will block the top BDS, so there is only one block job
950 * for the top BDS and its backing chain.
952 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_SOURCE,
953 parent->backing_blocker);
954 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_TARGET,
955 parent->backing_blocker);
958 static void bdrv_backing_detach(BdrvChild *c)
960 BlockDriverState *parent = c->opaque;
962 assert(parent->backing_blocker);
963 bdrv_op_unblock_all(c->bs, parent->backing_blocker);
964 error_free(parent->backing_blocker);
965 parent->backing_blocker = NULL;
969 * Returns the options and flags that bs->backing should get, based on the
970 * given options and flags for the parent BDS
972 static void bdrv_backing_options(int *child_flags, QDict *child_options,
973 int parent_flags, QDict *parent_options)
975 int flags = parent_flags;
977 /* The cache mode is inherited unmodified for backing files; except WCE,
978 * which is only applied on the top level (BlockBackend) */
979 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
980 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
981 qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
983 /* backing files always opened read-only */
984 qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on");
985 flags &= ~BDRV_O_COPY_ON_READ;
987 /* snapshot=on is handled on the top layer */
988 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY);
990 *child_flags = flags;
993 static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
994 const char *filename, Error **errp)
996 BlockDriverState *parent = c->opaque;
997 int orig_flags = bdrv_get_flags(parent);
998 int ret;
1000 if (!(orig_flags & BDRV_O_RDWR)) {
1001 ret = bdrv_reopen(parent, orig_flags | BDRV_O_RDWR, errp);
1002 if (ret < 0) {
1003 return ret;
1007 ret = bdrv_change_backing_file(parent, filename,
1008 base->drv ? base->drv->format_name : "");
1009 if (ret < 0) {
1010 error_setg_errno(errp, -ret, "Could not update backing file link");
1013 if (!(orig_flags & BDRV_O_RDWR)) {
1014 bdrv_reopen(parent, orig_flags, NULL);
1017 return ret;
1020 const BdrvChildRole child_backing = {
1021 .get_parent_desc = bdrv_child_get_parent_desc,
1022 .attach = bdrv_backing_attach,
1023 .detach = bdrv_backing_detach,
1024 .inherit_options = bdrv_backing_options,
1025 .drained_begin = bdrv_child_cb_drained_begin,
1026 .drained_end = bdrv_child_cb_drained_end,
1027 .inactivate = bdrv_child_cb_inactivate,
1028 .update_filename = bdrv_backing_update_filename,
1031 static int bdrv_open_flags(BlockDriverState *bs, int flags)
1033 int open_flags = flags;
1036 * Clear flags that are internal to the block layer before opening the
1037 * image.
1039 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL);
1042 * Snapshots should be writable.
1044 if (flags & BDRV_O_TEMPORARY) {
1045 open_flags |= BDRV_O_RDWR;
1048 return open_flags;
1051 static void update_flags_from_options(int *flags, QemuOpts *opts)
1053 *flags &= ~BDRV_O_CACHE_MASK;
1055 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_NO_FLUSH));
1056 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
1057 *flags |= BDRV_O_NO_FLUSH;
1060 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT));
1061 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_DIRECT, false)) {
1062 *flags |= BDRV_O_NOCACHE;
1065 *flags &= ~BDRV_O_RDWR;
1067 assert(qemu_opt_find(opts, BDRV_OPT_READ_ONLY));
1068 if (!qemu_opt_get_bool(opts, BDRV_OPT_READ_ONLY, false)) {
1069 *flags |= BDRV_O_RDWR;
1074 static void update_options_from_flags(QDict *options, int flags)
1076 if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) {
1077 qdict_put_bool(options, BDRV_OPT_CACHE_DIRECT, flags & BDRV_O_NOCACHE);
1079 if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) {
1080 qdict_put_bool(options, BDRV_OPT_CACHE_NO_FLUSH,
1081 flags & BDRV_O_NO_FLUSH);
1083 if (!qdict_haskey(options, BDRV_OPT_READ_ONLY)) {
1084 qdict_put_bool(options, BDRV_OPT_READ_ONLY, !(flags & BDRV_O_RDWR));
1088 static void bdrv_assign_node_name(BlockDriverState *bs,
1089 const char *node_name,
1090 Error **errp)
1092 char *gen_node_name = NULL;
1094 if (!node_name) {
1095 node_name = gen_node_name = id_generate(ID_BLOCK);
1096 } else if (!id_wellformed(node_name)) {
1098 * Check for empty string or invalid characters, but not if it is
1099 * generated (generated names use characters not available to the user)
1101 error_setg(errp, "Invalid node name");
1102 return;
1105 /* takes care of avoiding namespaces collisions */
1106 if (blk_by_name(node_name)) {
1107 error_setg(errp, "node-name=%s is conflicting with a device id",
1108 node_name);
1109 goto out;
1112 /* takes care of avoiding duplicates node names */
1113 if (bdrv_find_node(node_name)) {
1114 error_setg(errp, "Duplicate node name");
1115 goto out;
1118 /* copy node name into the bs and insert it into the graph list */
1119 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
1120 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
1121 out:
1122 g_free(gen_node_name);
1125 static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv,
1126 const char *node_name, QDict *options,
1127 int open_flags, Error **errp)
1129 Error *local_err = NULL;
1130 int ret;
1132 bdrv_assign_node_name(bs, node_name, &local_err);
1133 if (local_err) {
1134 error_propagate(errp, local_err);
1135 return -EINVAL;
1138 bs->drv = drv;
1139 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
1140 bs->opaque = g_malloc0(drv->instance_size);
1142 if (drv->bdrv_file_open) {
1143 assert(!drv->bdrv_needs_filename || bs->filename[0]);
1144 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err);
1145 } else if (drv->bdrv_open) {
1146 ret = drv->bdrv_open(bs, options, open_flags, &local_err);
1147 } else {
1148 ret = 0;
1151 if (ret < 0) {
1152 if (local_err) {
1153 error_propagate(errp, local_err);
1154 } else if (bs->filename[0]) {
1155 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename);
1156 } else {
1157 error_setg_errno(errp, -ret, "Could not open image");
1159 goto open_failed;
1162 ret = refresh_total_sectors(bs, bs->total_sectors);
1163 if (ret < 0) {
1164 error_setg_errno(errp, -ret, "Could not refresh total sector count");
1165 return ret;
1168 bdrv_refresh_limits(bs, &local_err);
1169 if (local_err) {
1170 error_propagate(errp, local_err);
1171 return -EINVAL;
1174 assert(bdrv_opt_mem_align(bs) != 0);
1175 assert(bdrv_min_mem_align(bs) != 0);
1176 assert(is_power_of_2(bs->bl.request_alignment));
1178 return 0;
1179 open_failed:
1180 bs->drv = NULL;
1181 if (bs->file != NULL) {
1182 bdrv_unref_child(bs, bs->file);
1183 bs->file = NULL;
1185 g_free(bs->opaque);
1186 bs->opaque = NULL;
1187 return ret;
1190 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
1191 int flags, Error **errp)
1193 BlockDriverState *bs;
1194 int ret;
1196 bs = bdrv_new();
1197 bs->open_flags = flags;
1198 bs->explicit_options = qdict_new();
1199 bs->options = qdict_new();
1200 bs->opaque = NULL;
1202 update_options_from_flags(bs->options, flags);
1204 ret = bdrv_open_driver(bs, drv, node_name, bs->options, flags, errp);
1205 if (ret < 0) {
1206 QDECREF(bs->explicit_options);
1207 bs->explicit_options = NULL;
1208 QDECREF(bs->options);
1209 bs->options = NULL;
1210 bdrv_unref(bs);
1211 return NULL;
1214 return bs;
1217 QemuOptsList bdrv_runtime_opts = {
1218 .name = "bdrv_common",
1219 .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head),
1220 .desc = {
1222 .name = "node-name",
1223 .type = QEMU_OPT_STRING,
1224 .help = "Node name of the block device node",
1227 .name = "driver",
1228 .type = QEMU_OPT_STRING,
1229 .help = "Block driver to use for the node",
1232 .name = BDRV_OPT_CACHE_DIRECT,
1233 .type = QEMU_OPT_BOOL,
1234 .help = "Bypass software writeback cache on the host",
1237 .name = BDRV_OPT_CACHE_NO_FLUSH,
1238 .type = QEMU_OPT_BOOL,
1239 .help = "Ignore flush requests",
1242 .name = BDRV_OPT_READ_ONLY,
1243 .type = QEMU_OPT_BOOL,
1244 .help = "Node is opened in read-only mode",
1247 .name = "detect-zeroes",
1248 .type = QEMU_OPT_STRING,
1249 .help = "try to optimize zero writes (off, on, unmap)",
1252 .name = "discard",
1253 .type = QEMU_OPT_STRING,
1254 .help = "discard operation (ignore/off, unmap/on)",
1257 .name = BDRV_OPT_FORCE_SHARE,
1258 .type = QEMU_OPT_BOOL,
1259 .help = "always accept other writers (default: off)",
1261 { /* end of list */ }
1266 * Common part for opening disk images and files
1268 * Removes all processed options from *options.
1270 static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file,
1271 QDict *options, Error **errp)
1273 int ret, open_flags;
1274 const char *filename;
1275 const char *driver_name = NULL;
1276 const char *node_name = NULL;
1277 const char *discard;
1278 const char *detect_zeroes;
1279 QemuOpts *opts;
1280 BlockDriver *drv;
1281 Error *local_err = NULL;
1283 assert(bs->file == NULL);
1284 assert(options != NULL && bs->options != options);
1286 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
1287 qemu_opts_absorb_qdict(opts, options, &local_err);
1288 if (local_err) {
1289 error_propagate(errp, local_err);
1290 ret = -EINVAL;
1291 goto fail_opts;
1294 update_flags_from_options(&bs->open_flags, opts);
1296 driver_name = qemu_opt_get(opts, "driver");
1297 drv = bdrv_find_format(driver_name);
1298 assert(drv != NULL);
1300 bs->force_share = qemu_opt_get_bool(opts, BDRV_OPT_FORCE_SHARE, false);
1302 if (bs->force_share && (bs->open_flags & BDRV_O_RDWR)) {
1303 error_setg(errp,
1304 BDRV_OPT_FORCE_SHARE
1305 "=on can only be used with read-only images");
1306 ret = -EINVAL;
1307 goto fail_opts;
1310 if (file != NULL) {
1311 filename = blk_bs(file)->filename;
1312 } else {
1314 * Caution: while qdict_get_try_str() is fine, getting
1315 * non-string types would require more care. When @options
1316 * come from -blockdev or blockdev_add, its members are typed
1317 * according to the QAPI schema, but when they come from
1318 * -drive, they're all QString.
1320 filename = qdict_get_try_str(options, "filename");
1323 if (drv->bdrv_needs_filename && (!filename || !filename[0])) {
1324 error_setg(errp, "The '%s' block driver requires a file name",
1325 drv->format_name);
1326 ret = -EINVAL;
1327 goto fail_opts;
1330 trace_bdrv_open_common(bs, filename ?: "", bs->open_flags,
1331 drv->format_name);
1333 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
1335 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
1336 error_setg(errp,
1337 !bs->read_only && bdrv_is_whitelisted(drv, true)
1338 ? "Driver '%s' can only be used for read-only devices"
1339 : "Driver '%s' is not whitelisted",
1340 drv->format_name);
1341 ret = -ENOTSUP;
1342 goto fail_opts;
1345 /* bdrv_new() and bdrv_close() make it so */
1346 assert(atomic_read(&bs->copy_on_read) == 0);
1348 if (bs->open_flags & BDRV_O_COPY_ON_READ) {
1349 if (!bs->read_only) {
1350 bdrv_enable_copy_on_read(bs);
1351 } else {
1352 error_setg(errp, "Can't use copy-on-read on read-only device");
1353 ret = -EINVAL;
1354 goto fail_opts;
1358 discard = qemu_opt_get(opts, "discard");
1359 if (discard != NULL) {
1360 if (bdrv_parse_discard_flags(discard, &bs->open_flags) != 0) {
1361 error_setg(errp, "Invalid discard option");
1362 ret = -EINVAL;
1363 goto fail_opts;
1367 detect_zeroes = qemu_opt_get(opts, "detect-zeroes");
1368 if (detect_zeroes) {
1369 BlockdevDetectZeroesOptions value =
1370 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup,
1371 detect_zeroes,
1372 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
1373 &local_err);
1374 if (local_err) {
1375 error_propagate(errp, local_err);
1376 ret = -EINVAL;
1377 goto fail_opts;
1380 if (value == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
1381 !(bs->open_flags & BDRV_O_UNMAP))
1383 error_setg(errp, "setting detect-zeroes to unmap is not allowed "
1384 "without setting discard operation to unmap");
1385 ret = -EINVAL;
1386 goto fail_opts;
1389 bs->detect_zeroes = value;
1392 if (filename != NULL) {
1393 pstrcpy(bs->filename, sizeof(bs->filename), filename);
1394 } else {
1395 bs->filename[0] = '\0';
1397 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename);
1399 /* Open the image, either directly or using a protocol */
1400 open_flags = bdrv_open_flags(bs, bs->open_flags);
1401 node_name = qemu_opt_get(opts, "node-name");
1403 assert(!drv->bdrv_file_open || file == NULL);
1404 ret = bdrv_open_driver(bs, drv, node_name, options, open_flags, errp);
1405 if (ret < 0) {
1406 goto fail_opts;
1409 qemu_opts_del(opts);
1410 return 0;
1412 fail_opts:
1413 qemu_opts_del(opts);
1414 return ret;
1417 static QDict *parse_json_filename(const char *filename, Error **errp)
1419 QObject *options_obj;
1420 QDict *options;
1421 int ret;
1423 ret = strstart(filename, "json:", &filename);
1424 assert(ret);
1426 options_obj = qobject_from_json(filename, errp);
1427 if (!options_obj) {
1428 /* Work around qobject_from_json() lossage TODO fix that */
1429 if (errp && !*errp) {
1430 error_setg(errp, "Could not parse the JSON options");
1431 return NULL;
1433 error_prepend(errp, "Could not parse the JSON options: ");
1434 return NULL;
1437 options = qobject_to_qdict(options_obj);
1438 if (!options) {
1439 qobject_decref(options_obj);
1440 error_setg(errp, "Invalid JSON object given");
1441 return NULL;
1444 qdict_flatten(options);
1446 return options;
1449 static void parse_json_protocol(QDict *options, const char **pfilename,
1450 Error **errp)
1452 QDict *json_options;
1453 Error *local_err = NULL;
1455 /* Parse json: pseudo-protocol */
1456 if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) {
1457 return;
1460 json_options = parse_json_filename(*pfilename, &local_err);
1461 if (local_err) {
1462 error_propagate(errp, local_err);
1463 return;
1466 /* Options given in the filename have lower priority than options
1467 * specified directly */
1468 qdict_join(options, json_options, false);
1469 QDECREF(json_options);
1470 *pfilename = NULL;
1474 * Fills in default options for opening images and converts the legacy
1475 * filename/flags pair to option QDict entries.
1476 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1477 * block driver has been specified explicitly.
1479 static int bdrv_fill_options(QDict **options, const char *filename,
1480 int *flags, Error **errp)
1482 const char *drvname;
1483 bool protocol = *flags & BDRV_O_PROTOCOL;
1484 bool parse_filename = false;
1485 BlockDriver *drv = NULL;
1486 Error *local_err = NULL;
1489 * Caution: while qdict_get_try_str() is fine, getting non-string
1490 * types would require more care. When @options come from
1491 * -blockdev or blockdev_add, its members are typed according to
1492 * the QAPI schema, but when they come from -drive, they're all
1493 * QString.
1495 drvname = qdict_get_try_str(*options, "driver");
1496 if (drvname) {
1497 drv = bdrv_find_format(drvname);
1498 if (!drv) {
1499 error_setg(errp, "Unknown driver '%s'", drvname);
1500 return -ENOENT;
1502 /* If the user has explicitly specified the driver, this choice should
1503 * override the BDRV_O_PROTOCOL flag */
1504 protocol = drv->bdrv_file_open;
1507 if (protocol) {
1508 *flags |= BDRV_O_PROTOCOL;
1509 } else {
1510 *flags &= ~BDRV_O_PROTOCOL;
1513 /* Translate cache options from flags into options */
1514 update_options_from_flags(*options, *flags);
1516 /* Fetch the file name from the options QDict if necessary */
1517 if (protocol && filename) {
1518 if (!qdict_haskey(*options, "filename")) {
1519 qdict_put_str(*options, "filename", filename);
1520 parse_filename = true;
1521 } else {
1522 error_setg(errp, "Can't specify 'file' and 'filename' options at "
1523 "the same time");
1524 return -EINVAL;
1528 /* Find the right block driver */
1529 /* See cautionary note on accessing @options above */
1530 filename = qdict_get_try_str(*options, "filename");
1532 if (!drvname && protocol) {
1533 if (filename) {
1534 drv = bdrv_find_protocol(filename, parse_filename, errp);
1535 if (!drv) {
1536 return -EINVAL;
1539 drvname = drv->format_name;
1540 qdict_put_str(*options, "driver", drvname);
1541 } else {
1542 error_setg(errp, "Must specify either driver or file");
1543 return -EINVAL;
1547 assert(drv || !protocol);
1549 /* Driver-specific filename parsing */
1550 if (drv && drv->bdrv_parse_filename && parse_filename) {
1551 drv->bdrv_parse_filename(filename, *options, &local_err);
1552 if (local_err) {
1553 error_propagate(errp, local_err);
1554 return -EINVAL;
1557 if (!drv->bdrv_needs_filename) {
1558 qdict_del(*options, "filename");
1562 return 0;
1565 static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q,
1566 uint64_t perm, uint64_t shared,
1567 GSList *ignore_children, Error **errp);
1568 static void bdrv_child_abort_perm_update(BdrvChild *c);
1569 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared);
1571 typedef struct BlockReopenQueueEntry {
1572 bool prepared;
1573 BDRVReopenState state;
1574 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry;
1575 } BlockReopenQueueEntry;
1578 * Return the flags that @bs will have after the reopens in @q have
1579 * successfully completed. If @q is NULL (or @bs is not contained in @q),
1580 * return the current flags.
1582 static int bdrv_reopen_get_flags(BlockReopenQueue *q, BlockDriverState *bs)
1584 BlockReopenQueueEntry *entry;
1586 if (q != NULL) {
1587 QSIMPLEQ_FOREACH(entry, q, entry) {
1588 if (entry->state.bs == bs) {
1589 return entry->state.flags;
1594 return bs->open_flags;
1597 /* Returns whether the image file can be written to after the reopen queue @q
1598 * has been successfully applied, or right now if @q is NULL. */
1599 static bool bdrv_is_writable(BlockDriverState *bs, BlockReopenQueue *q)
1601 int flags = bdrv_reopen_get_flags(q, bs);
1603 return (flags & (BDRV_O_RDWR | BDRV_O_INACTIVE)) == BDRV_O_RDWR;
1606 static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs,
1607 BdrvChild *c, const BdrvChildRole *role,
1608 BlockReopenQueue *reopen_queue,
1609 uint64_t parent_perm, uint64_t parent_shared,
1610 uint64_t *nperm, uint64_t *nshared)
1612 if (bs->drv && bs->drv->bdrv_child_perm) {
1613 bs->drv->bdrv_child_perm(bs, c, role, reopen_queue,
1614 parent_perm, parent_shared,
1615 nperm, nshared);
1617 /* TODO Take force_share from reopen_queue */
1618 if (child_bs && child_bs->force_share) {
1619 *nshared = BLK_PERM_ALL;
1624 * Check whether permissions on this node can be changed in a way that
1625 * @cumulative_perms and @cumulative_shared_perms are the new cumulative
1626 * permissions of all its parents. This involves checking whether all necessary
1627 * permission changes to child nodes can be performed.
1629 * A call to this function must always be followed by a call to bdrv_set_perm()
1630 * or bdrv_abort_perm_update().
1632 static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
1633 uint64_t cumulative_perms,
1634 uint64_t cumulative_shared_perms,
1635 GSList *ignore_children, Error **errp)
1637 BlockDriver *drv = bs->drv;
1638 BdrvChild *c;
1639 int ret;
1641 /* Write permissions never work with read-only images */
1642 if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) &&
1643 !bdrv_is_writable(bs, q))
1645 error_setg(errp, "Block node is read-only");
1646 return -EPERM;
1649 /* Check this node */
1650 if (!drv) {
1651 return 0;
1654 if (drv->bdrv_check_perm) {
1655 return drv->bdrv_check_perm(bs, cumulative_perms,
1656 cumulative_shared_perms, errp);
1659 /* Drivers that never have children can omit .bdrv_child_perm() */
1660 if (!drv->bdrv_child_perm) {
1661 assert(QLIST_EMPTY(&bs->children));
1662 return 0;
1665 /* Check all children */
1666 QLIST_FOREACH(c, &bs->children, next) {
1667 uint64_t cur_perm, cur_shared;
1668 bdrv_child_perm(bs, c->bs, c, c->role, q,
1669 cumulative_perms, cumulative_shared_perms,
1670 &cur_perm, &cur_shared);
1671 ret = bdrv_child_check_perm(c, q, cur_perm, cur_shared,
1672 ignore_children, errp);
1673 if (ret < 0) {
1674 return ret;
1678 return 0;
1682 * Notifies drivers that after a previous bdrv_check_perm() call, the
1683 * permission update is not performed and any preparations made for it (e.g.
1684 * taken file locks) need to be undone.
1686 * This function recursively notifies all child nodes.
1688 static void bdrv_abort_perm_update(BlockDriverState *bs)
1690 BlockDriver *drv = bs->drv;
1691 BdrvChild *c;
1693 if (!drv) {
1694 return;
1697 if (drv->bdrv_abort_perm_update) {
1698 drv->bdrv_abort_perm_update(bs);
1701 QLIST_FOREACH(c, &bs->children, next) {
1702 bdrv_child_abort_perm_update(c);
1706 static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms,
1707 uint64_t cumulative_shared_perms)
1709 BlockDriver *drv = bs->drv;
1710 BdrvChild *c;
1712 if (!drv) {
1713 return;
1716 /* Update this node */
1717 if (drv->bdrv_set_perm) {
1718 drv->bdrv_set_perm(bs, cumulative_perms, cumulative_shared_perms);
1721 /* Drivers that never have children can omit .bdrv_child_perm() */
1722 if (!drv->bdrv_child_perm) {
1723 assert(QLIST_EMPTY(&bs->children));
1724 return;
1727 /* Update all children */
1728 QLIST_FOREACH(c, &bs->children, next) {
1729 uint64_t cur_perm, cur_shared;
1730 bdrv_child_perm(bs, c->bs, c, c->role, NULL,
1731 cumulative_perms, cumulative_shared_perms,
1732 &cur_perm, &cur_shared);
1733 bdrv_child_set_perm(c, cur_perm, cur_shared);
1737 static void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm,
1738 uint64_t *shared_perm)
1740 BdrvChild *c;
1741 uint64_t cumulative_perms = 0;
1742 uint64_t cumulative_shared_perms = BLK_PERM_ALL;
1744 QLIST_FOREACH(c, &bs->parents, next_parent) {
1745 cumulative_perms |= c->perm;
1746 cumulative_shared_perms &= c->shared_perm;
1749 *perm = cumulative_perms;
1750 *shared_perm = cumulative_shared_perms;
1753 static char *bdrv_child_user_desc(BdrvChild *c)
1755 if (c->role->get_parent_desc) {
1756 return c->role->get_parent_desc(c);
1759 return g_strdup("another user");
1762 char *bdrv_perm_names(uint64_t perm)
1764 struct perm_name {
1765 uint64_t perm;
1766 const char *name;
1767 } permissions[] = {
1768 { BLK_PERM_CONSISTENT_READ, "consistent read" },
1769 { BLK_PERM_WRITE, "write" },
1770 { BLK_PERM_WRITE_UNCHANGED, "write unchanged" },
1771 { BLK_PERM_RESIZE, "resize" },
1772 { BLK_PERM_GRAPH_MOD, "change children" },
1773 { 0, NULL }
1776 char *result = g_strdup("");
1777 struct perm_name *p;
1779 for (p = permissions; p->name; p++) {
1780 if (perm & p->perm) {
1781 char *old = result;
1782 result = g_strdup_printf("%s%s%s", old, *old ? ", " : "", p->name);
1783 g_free(old);
1787 return result;
1791 * Checks whether a new reference to @bs can be added if the new user requires
1792 * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is
1793 * set, the BdrvChild objects in this list are ignored in the calculations;
1794 * this allows checking permission updates for an existing reference.
1796 * Needs to be followed by a call to either bdrv_set_perm() or
1797 * bdrv_abort_perm_update(). */
1798 static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q,
1799 uint64_t new_used_perm,
1800 uint64_t new_shared_perm,
1801 GSList *ignore_children, Error **errp)
1803 BdrvChild *c;
1804 uint64_t cumulative_perms = new_used_perm;
1805 uint64_t cumulative_shared_perms = new_shared_perm;
1807 /* There is no reason why anyone couldn't tolerate write_unchanged */
1808 assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED);
1810 QLIST_FOREACH(c, &bs->parents, next_parent) {
1811 if (g_slist_find(ignore_children, c)) {
1812 continue;
1815 if ((new_used_perm & c->shared_perm) != new_used_perm) {
1816 char *user = bdrv_child_user_desc(c);
1817 char *perm_names = bdrv_perm_names(new_used_perm & ~c->shared_perm);
1818 error_setg(errp, "Conflicts with use by %s as '%s', which does not "
1819 "allow '%s' on %s",
1820 user, c->name, perm_names, bdrv_get_node_name(c->bs));
1821 g_free(user);
1822 g_free(perm_names);
1823 return -EPERM;
1826 if ((c->perm & new_shared_perm) != c->perm) {
1827 char *user = bdrv_child_user_desc(c);
1828 char *perm_names = bdrv_perm_names(c->perm & ~new_shared_perm);
1829 error_setg(errp, "Conflicts with use by %s as '%s', which uses "
1830 "'%s' on %s",
1831 user, c->name, perm_names, bdrv_get_node_name(c->bs));
1832 g_free(user);
1833 g_free(perm_names);
1834 return -EPERM;
1837 cumulative_perms |= c->perm;
1838 cumulative_shared_perms &= c->shared_perm;
1841 return bdrv_check_perm(bs, q, cumulative_perms, cumulative_shared_perms,
1842 ignore_children, errp);
1845 /* Needs to be followed by a call to either bdrv_child_set_perm() or
1846 * bdrv_child_abort_perm_update(). */
1847 static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q,
1848 uint64_t perm, uint64_t shared,
1849 GSList *ignore_children, Error **errp)
1851 int ret;
1853 ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c);
1854 ret = bdrv_check_update_perm(c->bs, q, perm, shared, ignore_children, errp);
1855 g_slist_free(ignore_children);
1857 return ret;
1860 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared)
1862 uint64_t cumulative_perms, cumulative_shared_perms;
1864 c->perm = perm;
1865 c->shared_perm = shared;
1867 bdrv_get_cumulative_perm(c->bs, &cumulative_perms,
1868 &cumulative_shared_perms);
1869 bdrv_set_perm(c->bs, cumulative_perms, cumulative_shared_perms);
1872 static void bdrv_child_abort_perm_update(BdrvChild *c)
1874 bdrv_abort_perm_update(c->bs);
1877 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
1878 Error **errp)
1880 int ret;
1882 ret = bdrv_child_check_perm(c, NULL, perm, shared, NULL, errp);
1883 if (ret < 0) {
1884 bdrv_child_abort_perm_update(c);
1885 return ret;
1888 bdrv_child_set_perm(c, perm, shared);
1890 return 0;
1893 #define DEFAULT_PERM_PASSTHROUGH (BLK_PERM_CONSISTENT_READ \
1894 | BLK_PERM_WRITE \
1895 | BLK_PERM_WRITE_UNCHANGED \
1896 | BLK_PERM_RESIZE)
1897 #define DEFAULT_PERM_UNCHANGED (BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH)
1899 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
1900 const BdrvChildRole *role,
1901 BlockReopenQueue *reopen_queue,
1902 uint64_t perm, uint64_t shared,
1903 uint64_t *nperm, uint64_t *nshared)
1905 if (c == NULL) {
1906 *nperm = perm & DEFAULT_PERM_PASSTHROUGH;
1907 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
1908 return;
1911 *nperm = (perm & DEFAULT_PERM_PASSTHROUGH) |
1912 (c->perm & DEFAULT_PERM_UNCHANGED);
1913 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) |
1914 (c->shared_perm & DEFAULT_PERM_UNCHANGED);
1917 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
1918 const BdrvChildRole *role,
1919 BlockReopenQueue *reopen_queue,
1920 uint64_t perm, uint64_t shared,
1921 uint64_t *nperm, uint64_t *nshared)
1923 bool backing = (role == &child_backing);
1924 assert(role == &child_backing || role == &child_file);
1926 if (!backing) {
1927 /* Apart from the modifications below, the same permissions are
1928 * forwarded and left alone as for filters */
1929 bdrv_filter_default_perms(bs, c, role, reopen_queue, perm, shared,
1930 &perm, &shared);
1932 /* Format drivers may touch metadata even if the guest doesn't write */
1933 if (bdrv_is_writable(bs, reopen_queue)) {
1934 perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
1937 /* bs->file always needs to be consistent because of the metadata. We
1938 * can never allow other users to resize or write to it. */
1939 perm |= BLK_PERM_CONSISTENT_READ;
1940 shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
1941 } else {
1942 /* We want consistent read from backing files if the parent needs it.
1943 * No other operations are performed on backing files. */
1944 perm &= BLK_PERM_CONSISTENT_READ;
1946 /* If the parent can deal with changing data, we're okay with a
1947 * writable and resizable backing file. */
1948 /* TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? */
1949 if (shared & BLK_PERM_WRITE) {
1950 shared = BLK_PERM_WRITE | BLK_PERM_RESIZE;
1951 } else {
1952 shared = 0;
1955 shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD |
1956 BLK_PERM_WRITE_UNCHANGED;
1959 if (bs->open_flags & BDRV_O_INACTIVE) {
1960 shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
1963 *nperm = perm;
1964 *nshared = shared;
1967 static void bdrv_replace_child_noperm(BdrvChild *child,
1968 BlockDriverState *new_bs)
1970 BlockDriverState *old_bs = child->bs;
1972 if (old_bs && new_bs) {
1973 assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs));
1975 if (old_bs) {
1976 if (old_bs->quiesce_counter && child->role->drained_end) {
1977 child->role->drained_end(child);
1979 if (child->role->detach) {
1980 child->role->detach(child);
1982 QLIST_REMOVE(child, next_parent);
1985 child->bs = new_bs;
1987 if (new_bs) {
1988 QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
1989 if (new_bs->quiesce_counter && child->role->drained_begin) {
1990 child->role->drained_begin(child);
1993 if (child->role->attach) {
1994 child->role->attach(child);
2000 * Updates @child to change its reference to point to @new_bs, including
2001 * checking and applying the necessary permisson updates both to the old node
2002 * and to @new_bs.
2004 * NULL is passed as @new_bs for removing the reference before freeing @child.
2006 * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this
2007 * function uses bdrv_set_perm() to update the permissions according to the new
2008 * reference that @new_bs gets.
2010 static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
2012 BlockDriverState *old_bs = child->bs;
2013 uint64_t perm, shared_perm;
2015 bdrv_replace_child_noperm(child, new_bs);
2017 if (old_bs) {
2018 /* Update permissions for old node. This is guaranteed to succeed
2019 * because we're just taking a parent away, so we're loosening
2020 * restrictions. */
2021 bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm);
2022 bdrv_check_perm(old_bs, NULL, perm, shared_perm, NULL, &error_abort);
2023 bdrv_set_perm(old_bs, perm, shared_perm);
2026 if (new_bs) {
2027 bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm);
2028 bdrv_set_perm(new_bs, perm, shared_perm);
2032 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
2033 const char *child_name,
2034 const BdrvChildRole *child_role,
2035 uint64_t perm, uint64_t shared_perm,
2036 void *opaque, Error **errp)
2038 BdrvChild *child;
2039 int ret;
2041 ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, errp);
2042 if (ret < 0) {
2043 bdrv_abort_perm_update(child_bs);
2044 return NULL;
2047 child = g_new(BdrvChild, 1);
2048 *child = (BdrvChild) {
2049 .bs = NULL,
2050 .name = g_strdup(child_name),
2051 .role = child_role,
2052 .perm = perm,
2053 .shared_perm = shared_perm,
2054 .opaque = opaque,
2057 /* This performs the matching bdrv_set_perm() for the above check. */
2058 bdrv_replace_child(child, child_bs);
2060 return child;
2063 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
2064 BlockDriverState *child_bs,
2065 const char *child_name,
2066 const BdrvChildRole *child_role,
2067 Error **errp)
2069 BdrvChild *child;
2070 uint64_t perm, shared_perm;
2072 bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm);
2074 assert(parent_bs->drv);
2075 assert(bdrv_get_aio_context(parent_bs) == bdrv_get_aio_context(child_bs));
2076 bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL,
2077 perm, shared_perm, &perm, &shared_perm);
2079 child = bdrv_root_attach_child(child_bs, child_name, child_role,
2080 perm, shared_perm, parent_bs, errp);
2081 if (child == NULL) {
2082 return NULL;
2085 QLIST_INSERT_HEAD(&parent_bs->children, child, next);
2086 return child;
2089 static void bdrv_detach_child(BdrvChild *child)
2091 if (child->next.le_prev) {
2092 QLIST_REMOVE(child, next);
2093 child->next.le_prev = NULL;
2096 bdrv_replace_child(child, NULL);
2098 g_free(child->name);
2099 g_free(child);
2102 void bdrv_root_unref_child(BdrvChild *child)
2104 BlockDriverState *child_bs;
2106 child_bs = child->bs;
2107 bdrv_detach_child(child);
2108 bdrv_unref(child_bs);
2111 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child)
2113 if (child == NULL) {
2114 return;
2117 if (child->bs->inherits_from == parent) {
2118 BdrvChild *c;
2120 /* Remove inherits_from only when the last reference between parent and
2121 * child->bs goes away. */
2122 QLIST_FOREACH(c, &parent->children, next) {
2123 if (c != child && c->bs == child->bs) {
2124 break;
2127 if (c == NULL) {
2128 child->bs->inherits_from = NULL;
2132 bdrv_root_unref_child(child);
2136 static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load)
2138 BdrvChild *c;
2139 QLIST_FOREACH(c, &bs->parents, next_parent) {
2140 if (c->role->change_media) {
2141 c->role->change_media(c, load);
2146 static void bdrv_parent_cb_resize(BlockDriverState *bs)
2148 BdrvChild *c;
2149 QLIST_FOREACH(c, &bs->parents, next_parent) {
2150 if (c->role->resize) {
2151 c->role->resize(c);
2157 * Sets the backing file link of a BDS. A new reference is created; callers
2158 * which don't need their own reference any more must call bdrv_unref().
2160 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
2161 Error **errp)
2163 if (backing_hd) {
2164 bdrv_ref(backing_hd);
2167 if (bs->backing) {
2168 bdrv_unref_child(bs, bs->backing);
2171 if (!backing_hd) {
2172 bs->backing = NULL;
2173 goto out;
2176 bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing,
2177 errp);
2178 if (!bs->backing) {
2179 bdrv_unref(backing_hd);
2182 bdrv_refresh_filename(bs);
2184 out:
2185 bdrv_refresh_limits(bs, NULL);
2189 * Opens the backing file for a BlockDriverState if not yet open
2191 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
2192 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2193 * itself, all options starting with "${bdref_key}." are considered part of the
2194 * BlockdevRef.
2196 * TODO Can this be unified with bdrv_open_image()?
2198 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
2199 const char *bdref_key, Error **errp)
2201 char *backing_filename = g_malloc0(PATH_MAX);
2202 char *bdref_key_dot;
2203 const char *reference = NULL;
2204 int ret = 0;
2205 BlockDriverState *backing_hd;
2206 QDict *options;
2207 QDict *tmp_parent_options = NULL;
2208 Error *local_err = NULL;
2210 if (bs->backing != NULL) {
2211 goto free_exit;
2214 /* NULL means an empty set of options */
2215 if (parent_options == NULL) {
2216 tmp_parent_options = qdict_new();
2217 parent_options = tmp_parent_options;
2220 bs->open_flags &= ~BDRV_O_NO_BACKING;
2222 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
2223 qdict_extract_subqdict(parent_options, &options, bdref_key_dot);
2224 g_free(bdref_key_dot);
2227 * Caution: while qdict_get_try_str() is fine, getting non-string
2228 * types would require more care. When @parent_options come from
2229 * -blockdev or blockdev_add, its members are typed according to
2230 * the QAPI schema, but when they come from -drive, they're all
2231 * QString.
2233 reference = qdict_get_try_str(parent_options, bdref_key);
2234 if (reference || qdict_haskey(options, "file.filename")) {
2235 backing_filename[0] = '\0';
2236 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
2237 QDECREF(options);
2238 goto free_exit;
2239 } else {
2240 bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX,
2241 &local_err);
2242 if (local_err) {
2243 ret = -EINVAL;
2244 error_propagate(errp, local_err);
2245 QDECREF(options);
2246 goto free_exit;
2250 if (!bs->drv || !bs->drv->supports_backing) {
2251 ret = -EINVAL;
2252 error_setg(errp, "Driver doesn't support backing files");
2253 QDECREF(options);
2254 goto free_exit;
2257 if (!reference &&
2258 bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) {
2259 qdict_put_str(options, "driver", bs->backing_format);
2262 backing_hd = bdrv_open_inherit(*backing_filename ? backing_filename : NULL,
2263 reference, options, 0, bs, &child_backing,
2264 errp);
2265 if (!backing_hd) {
2266 bs->open_flags |= BDRV_O_NO_BACKING;
2267 error_prepend(errp, "Could not open backing file: ");
2268 ret = -EINVAL;
2269 goto free_exit;
2271 bdrv_set_aio_context(backing_hd, bdrv_get_aio_context(bs));
2273 /* Hook up the backing file link; drop our reference, bs owns the
2274 * backing_hd reference now */
2275 bdrv_set_backing_hd(bs, backing_hd, &local_err);
2276 bdrv_unref(backing_hd);
2277 if (local_err) {
2278 error_propagate(errp, local_err);
2279 ret = -EINVAL;
2280 goto free_exit;
2283 qdict_del(parent_options, bdref_key);
2285 free_exit:
2286 g_free(backing_filename);
2287 QDECREF(tmp_parent_options);
2288 return ret;
2291 static BlockDriverState *
2292 bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
2293 BlockDriverState *parent, const BdrvChildRole *child_role,
2294 bool allow_none, Error **errp)
2296 BlockDriverState *bs = NULL;
2297 QDict *image_options;
2298 char *bdref_key_dot;
2299 const char *reference;
2301 assert(child_role != NULL);
2303 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
2304 qdict_extract_subqdict(options, &image_options, bdref_key_dot);
2305 g_free(bdref_key_dot);
2308 * Caution: while qdict_get_try_str() is fine, getting non-string
2309 * types would require more care. When @options come from
2310 * -blockdev or blockdev_add, its members are typed according to
2311 * the QAPI schema, but when they come from -drive, they're all
2312 * QString.
2314 reference = qdict_get_try_str(options, bdref_key);
2315 if (!filename && !reference && !qdict_size(image_options)) {
2316 if (!allow_none) {
2317 error_setg(errp, "A block device must be specified for \"%s\"",
2318 bdref_key);
2320 QDECREF(image_options);
2321 goto done;
2324 bs = bdrv_open_inherit(filename, reference, image_options, 0,
2325 parent, child_role, errp);
2326 if (!bs) {
2327 goto done;
2330 done:
2331 qdict_del(options, bdref_key);
2332 return bs;
2336 * Opens a disk image whose options are given as BlockdevRef in another block
2337 * device's options.
2339 * If allow_none is true, no image will be opened if filename is false and no
2340 * BlockdevRef is given. NULL will be returned, but errp remains unset.
2342 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
2343 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2344 * itself, all options starting with "${bdref_key}." are considered part of the
2345 * BlockdevRef.
2347 * The BlockdevRef will be removed from the options QDict.
2349 BdrvChild *bdrv_open_child(const char *filename,
2350 QDict *options, const char *bdref_key,
2351 BlockDriverState *parent,
2352 const BdrvChildRole *child_role,
2353 bool allow_none, Error **errp)
2355 BdrvChild *c;
2356 BlockDriverState *bs;
2358 bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_role,
2359 allow_none, errp);
2360 if (bs == NULL) {
2361 return NULL;
2364 c = bdrv_attach_child(parent, bs, bdref_key, child_role, errp);
2365 if (!c) {
2366 bdrv_unref(bs);
2367 return NULL;
2370 return c;
2373 static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
2374 int flags,
2375 QDict *snapshot_options,
2376 Error **errp)
2378 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
2379 char *tmp_filename = g_malloc0(PATH_MAX + 1);
2380 int64_t total_size;
2381 QemuOpts *opts = NULL;
2382 BlockDriverState *bs_snapshot = NULL;
2383 Error *local_err = NULL;
2384 int ret;
2386 /* if snapshot, we create a temporary backing file and open it
2387 instead of opening 'filename' directly */
2389 /* Get the required size from the image */
2390 total_size = bdrv_getlength(bs);
2391 if (total_size < 0) {
2392 error_setg_errno(errp, -total_size, "Could not get image size");
2393 goto out;
2396 /* Create the temporary image */
2397 ret = get_tmp_filename(tmp_filename, PATH_MAX + 1);
2398 if (ret < 0) {
2399 error_setg_errno(errp, -ret, "Could not get temporary filename");
2400 goto out;
2403 opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0,
2404 &error_abort);
2405 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort);
2406 ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp);
2407 qemu_opts_del(opts);
2408 if (ret < 0) {
2409 error_prepend(errp, "Could not create temporary overlay '%s': ",
2410 tmp_filename);
2411 goto out;
2414 /* Prepare options QDict for the temporary file */
2415 qdict_put_str(snapshot_options, "file.driver", "file");
2416 qdict_put_str(snapshot_options, "file.filename", tmp_filename);
2417 qdict_put_str(snapshot_options, "driver", "qcow2");
2419 bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp);
2420 snapshot_options = NULL;
2421 if (!bs_snapshot) {
2422 goto out;
2425 /* bdrv_append() consumes a strong reference to bs_snapshot
2426 * (i.e. it will call bdrv_unref() on it) even on error, so in
2427 * order to be able to return one, we have to increase
2428 * bs_snapshot's refcount here */
2429 bdrv_ref(bs_snapshot);
2430 bdrv_append(bs_snapshot, bs, &local_err);
2431 if (local_err) {
2432 error_propagate(errp, local_err);
2433 bs_snapshot = NULL;
2434 goto out;
2437 out:
2438 QDECREF(snapshot_options);
2439 g_free(tmp_filename);
2440 return bs_snapshot;
2444 * Opens a disk image (raw, qcow2, vmdk, ...)
2446 * options is a QDict of options to pass to the block drivers, or NULL for an
2447 * empty set of options. The reference to the QDict belongs to the block layer
2448 * after the call (even on failure), so if the caller intends to reuse the
2449 * dictionary, it needs to use QINCREF() before calling bdrv_open.
2451 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
2452 * If it is not NULL, the referenced BDS will be reused.
2454 * The reference parameter may be used to specify an existing block device which
2455 * should be opened. If specified, neither options nor a filename may be given,
2456 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
2458 static BlockDriverState *bdrv_open_inherit(const char *filename,
2459 const char *reference,
2460 QDict *options, int flags,
2461 BlockDriverState *parent,
2462 const BdrvChildRole *child_role,
2463 Error **errp)
2465 int ret;
2466 BlockBackend *file = NULL;
2467 BlockDriverState *bs;
2468 BlockDriver *drv = NULL;
2469 const char *drvname;
2470 const char *backing;
2471 Error *local_err = NULL;
2472 QDict *snapshot_options = NULL;
2473 int snapshot_flags = 0;
2475 assert(!child_role || !flags);
2476 assert(!child_role == !parent);
2478 if (reference) {
2479 bool options_non_empty = options ? qdict_size(options) : false;
2480 QDECREF(options);
2482 if (filename || options_non_empty) {
2483 error_setg(errp, "Cannot reference an existing block device with "
2484 "additional options or a new filename");
2485 return NULL;
2488 bs = bdrv_lookup_bs(reference, reference, errp);
2489 if (!bs) {
2490 return NULL;
2493 bdrv_ref(bs);
2494 return bs;
2497 bs = bdrv_new();
2499 /* NULL means an empty set of options */
2500 if (options == NULL) {
2501 options = qdict_new();
2504 /* json: syntax counts as explicit options, as if in the QDict */
2505 parse_json_protocol(options, &filename, &local_err);
2506 if (local_err) {
2507 goto fail;
2510 bs->explicit_options = qdict_clone_shallow(options);
2512 if (child_role) {
2513 bs->inherits_from = parent;
2514 child_role->inherit_options(&flags, options,
2515 parent->open_flags, parent->options);
2518 ret = bdrv_fill_options(&options, filename, &flags, &local_err);
2519 if (local_err) {
2520 goto fail;
2524 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
2525 * Caution: getting a boolean member of @options requires care.
2526 * When @options come from -blockdev or blockdev_add, members are
2527 * typed according to the QAPI schema, but when they come from
2528 * -drive, they're all QString.
2530 if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") &&
2531 !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) {
2532 flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR);
2533 } else {
2534 flags &= ~BDRV_O_RDWR;
2537 if (flags & BDRV_O_SNAPSHOT) {
2538 snapshot_options = qdict_new();
2539 bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options,
2540 flags, options);
2541 /* Let bdrv_backing_options() override "read-only" */
2542 qdict_del(options, BDRV_OPT_READ_ONLY);
2543 bdrv_backing_options(&flags, options, flags, options);
2546 bs->open_flags = flags;
2547 bs->options = options;
2548 options = qdict_clone_shallow(options);
2550 /* Find the right image format driver */
2551 /* See cautionary note on accessing @options above */
2552 drvname = qdict_get_try_str(options, "driver");
2553 if (drvname) {
2554 drv = bdrv_find_format(drvname);
2555 if (!drv) {
2556 error_setg(errp, "Unknown driver: '%s'", drvname);
2557 goto fail;
2561 assert(drvname || !(flags & BDRV_O_PROTOCOL));
2563 /* See cautionary note on accessing @options above */
2564 backing = qdict_get_try_str(options, "backing");
2565 if (backing && *backing == '\0') {
2566 flags |= BDRV_O_NO_BACKING;
2567 qdict_del(options, "backing");
2570 /* Open image file without format layer. This BlockBackend is only used for
2571 * probing, the block drivers will do their own bdrv_open_child() for the
2572 * same BDS, which is why we put the node name back into options. */
2573 if ((flags & BDRV_O_PROTOCOL) == 0) {
2574 BlockDriverState *file_bs;
2576 file_bs = bdrv_open_child_bs(filename, options, "file", bs,
2577 &child_file, true, &local_err);
2578 if (local_err) {
2579 goto fail;
2581 if (file_bs != NULL) {
2582 /* Not requesting BLK_PERM_CONSISTENT_READ because we're only
2583 * looking at the header to guess the image format. This works even
2584 * in cases where a guest would not see a consistent state. */
2585 file = blk_new(0, BLK_PERM_ALL);
2586 blk_insert_bs(file, file_bs, &local_err);
2587 bdrv_unref(file_bs);
2588 if (local_err) {
2589 goto fail;
2592 qdict_put_str(options, "file", bdrv_get_node_name(file_bs));
2596 /* Image format probing */
2597 bs->probed = !drv;
2598 if (!drv && file) {
2599 ret = find_image_format(file, filename, &drv, &local_err);
2600 if (ret < 0) {
2601 goto fail;
2604 * This option update would logically belong in bdrv_fill_options(),
2605 * but we first need to open bs->file for the probing to work, while
2606 * opening bs->file already requires the (mostly) final set of options
2607 * so that cache mode etc. can be inherited.
2609 * Adding the driver later is somewhat ugly, but it's not an option
2610 * that would ever be inherited, so it's correct. We just need to make
2611 * sure to update both bs->options (which has the full effective
2612 * options for bs) and options (which has file.* already removed).
2614 qdict_put_str(bs->options, "driver", drv->format_name);
2615 qdict_put_str(options, "driver", drv->format_name);
2616 } else if (!drv) {
2617 error_setg(errp, "Must specify either driver or file");
2618 goto fail;
2621 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
2622 assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open);
2623 /* file must be NULL if a protocol BDS is about to be created
2624 * (the inverse results in an error message from bdrv_open_common()) */
2625 assert(!(flags & BDRV_O_PROTOCOL) || !file);
2627 /* Open the image */
2628 ret = bdrv_open_common(bs, file, options, &local_err);
2629 if (ret < 0) {
2630 goto fail;
2633 if (file) {
2634 blk_unref(file);
2635 file = NULL;
2638 /* If there is a backing file, use it */
2639 if ((flags & BDRV_O_NO_BACKING) == 0) {
2640 ret = bdrv_open_backing_file(bs, options, "backing", &local_err);
2641 if (ret < 0) {
2642 goto close_and_fail;
2646 bdrv_refresh_filename(bs);
2648 /* Check if any unknown options were used */
2649 if (qdict_size(options) != 0) {
2650 const QDictEntry *entry = qdict_first(options);
2651 if (flags & BDRV_O_PROTOCOL) {
2652 error_setg(errp, "Block protocol '%s' doesn't support the option "
2653 "'%s'", drv->format_name, entry->key);
2654 } else {
2655 error_setg(errp,
2656 "Block format '%s' does not support the option '%s'",
2657 drv->format_name, entry->key);
2660 goto close_and_fail;
2663 bdrv_parent_cb_change_media(bs, true);
2665 QDECREF(options);
2667 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
2668 * temporary snapshot afterwards. */
2669 if (snapshot_flags) {
2670 BlockDriverState *snapshot_bs;
2671 snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags,
2672 snapshot_options, &local_err);
2673 snapshot_options = NULL;
2674 if (local_err) {
2675 goto close_and_fail;
2677 /* We are not going to return bs but the overlay on top of it
2678 * (snapshot_bs); thus, we have to drop the strong reference to bs
2679 * (which we obtained by calling bdrv_new()). bs will not be deleted,
2680 * though, because the overlay still has a reference to it. */
2681 bdrv_unref(bs);
2682 bs = snapshot_bs;
2685 return bs;
2687 fail:
2688 blk_unref(file);
2689 QDECREF(snapshot_options);
2690 QDECREF(bs->explicit_options);
2691 QDECREF(bs->options);
2692 QDECREF(options);
2693 bs->options = NULL;
2694 bs->explicit_options = NULL;
2695 bdrv_unref(bs);
2696 error_propagate(errp, local_err);
2697 return NULL;
2699 close_and_fail:
2700 bdrv_unref(bs);
2701 QDECREF(snapshot_options);
2702 QDECREF(options);
2703 error_propagate(errp, local_err);
2704 return NULL;
2707 BlockDriverState *bdrv_open(const char *filename, const char *reference,
2708 QDict *options, int flags, Error **errp)
2710 return bdrv_open_inherit(filename, reference, options, flags, NULL,
2711 NULL, errp);
2715 * Adds a BlockDriverState to a simple queue for an atomic, transactional
2716 * reopen of multiple devices.
2718 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT
2719 * already performed, or alternatively may be NULL a new BlockReopenQueue will
2720 * be created and initialized. This newly created BlockReopenQueue should be
2721 * passed back in for subsequent calls that are intended to be of the same
2722 * atomic 'set'.
2724 * bs is the BlockDriverState to add to the reopen queue.
2726 * options contains the changed options for the associated bs
2727 * (the BlockReopenQueue takes ownership)
2729 * flags contains the open flags for the associated bs
2731 * returns a pointer to bs_queue, which is either the newly allocated
2732 * bs_queue, or the existing bs_queue being used.
2735 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
2736 BlockDriverState *bs,
2737 QDict *options,
2738 int flags,
2739 const BdrvChildRole *role,
2740 QDict *parent_options,
2741 int parent_flags)
2743 assert(bs != NULL);
2745 BlockReopenQueueEntry *bs_entry;
2746 BdrvChild *child;
2747 QDict *old_options, *explicit_options;
2749 if (bs_queue == NULL) {
2750 bs_queue = g_new0(BlockReopenQueue, 1);
2751 QSIMPLEQ_INIT(bs_queue);
2754 if (!options) {
2755 options = qdict_new();
2758 /* Check if this BlockDriverState is already in the queue */
2759 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
2760 if (bs == bs_entry->state.bs) {
2761 break;
2766 * Precedence of options:
2767 * 1. Explicitly passed in options (highest)
2768 * 2. Set in flags (only for top level)
2769 * 3. Retained from explicitly set options of bs
2770 * 4. Inherited from parent node
2771 * 5. Retained from effective options of bs
2774 if (!parent_options) {
2776 * Any setting represented by flags is always updated. If the
2777 * corresponding QDict option is set, it takes precedence. Otherwise
2778 * the flag is translated into a QDict option. The old setting of bs is
2779 * not considered.
2781 update_options_from_flags(options, flags);
2784 /* Old explicitly set values (don't overwrite by inherited value) */
2785 if (bs_entry) {
2786 old_options = qdict_clone_shallow(bs_entry->state.explicit_options);
2787 } else {
2788 old_options = qdict_clone_shallow(bs->explicit_options);
2790 bdrv_join_options(bs, options, old_options);
2791 QDECREF(old_options);
2793 explicit_options = qdict_clone_shallow(options);
2795 /* Inherit from parent node */
2796 if (parent_options) {
2797 assert(!flags);
2798 role->inherit_options(&flags, options, parent_flags, parent_options);
2801 /* Old values are used for options that aren't set yet */
2802 old_options = qdict_clone_shallow(bs->options);
2803 bdrv_join_options(bs, options, old_options);
2804 QDECREF(old_options);
2806 /* bdrv_open_inherit() sets and clears some additional flags internally */
2807 flags &= ~BDRV_O_PROTOCOL;
2808 if (flags & BDRV_O_RDWR) {
2809 flags |= BDRV_O_ALLOW_RDWR;
2812 if (!bs_entry) {
2813 bs_entry = g_new0(BlockReopenQueueEntry, 1);
2814 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry);
2815 } else {
2816 QDECREF(bs_entry->state.options);
2817 QDECREF(bs_entry->state.explicit_options);
2820 bs_entry->state.bs = bs;
2821 bs_entry->state.options = options;
2822 bs_entry->state.explicit_options = explicit_options;
2823 bs_entry->state.flags = flags;
2825 /* This needs to be overwritten in bdrv_reopen_prepare() */
2826 bs_entry->state.perm = UINT64_MAX;
2827 bs_entry->state.shared_perm = 0;
2829 QLIST_FOREACH(child, &bs->children, next) {
2830 QDict *new_child_options;
2831 char *child_key_dot;
2833 /* reopen can only change the options of block devices that were
2834 * implicitly created and inherited options. For other (referenced)
2835 * block devices, a syntax like "backing.foo" results in an error. */
2836 if (child->bs->inherits_from != bs) {
2837 continue;
2840 child_key_dot = g_strdup_printf("%s.", child->name);
2841 qdict_extract_subqdict(options, &new_child_options, child_key_dot);
2842 g_free(child_key_dot);
2844 bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options, 0,
2845 child->role, options, flags);
2848 return bs_queue;
2851 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
2852 BlockDriverState *bs,
2853 QDict *options, int flags)
2855 return bdrv_reopen_queue_child(bs_queue, bs, options, flags,
2856 NULL, NULL, 0);
2860 * Reopen multiple BlockDriverStates atomically & transactionally.
2862 * The queue passed in (bs_queue) must have been built up previous
2863 * via bdrv_reopen_queue().
2865 * Reopens all BDS specified in the queue, with the appropriate
2866 * flags. All devices are prepared for reopen, and failure of any
2867 * device will cause all device changes to be abandonded, and intermediate
2868 * data cleaned up.
2870 * If all devices prepare successfully, then the changes are committed
2871 * to all devices.
2874 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp)
2876 int ret = -1;
2877 BlockReopenQueueEntry *bs_entry, *next;
2878 Error *local_err = NULL;
2880 assert(bs_queue != NULL);
2882 aio_context_release(ctx);
2883 bdrv_drain_all_begin();
2884 aio_context_acquire(ctx);
2886 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
2887 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) {
2888 error_propagate(errp, local_err);
2889 goto cleanup;
2891 bs_entry->prepared = true;
2894 /* If we reach this point, we have success and just need to apply the
2895 * changes
2897 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
2898 bdrv_reopen_commit(&bs_entry->state);
2901 ret = 0;
2903 cleanup:
2904 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
2905 if (ret && bs_entry->prepared) {
2906 bdrv_reopen_abort(&bs_entry->state);
2907 } else if (ret) {
2908 QDECREF(bs_entry->state.explicit_options);
2910 QDECREF(bs_entry->state.options);
2911 g_free(bs_entry);
2913 g_free(bs_queue);
2915 bdrv_drain_all_end();
2917 return ret;
2921 /* Reopen a single BlockDriverState with the specified flags. */
2922 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp)
2924 int ret = -1;
2925 Error *local_err = NULL;
2926 BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags);
2928 ret = bdrv_reopen_multiple(bdrv_get_aio_context(bs), queue, &local_err);
2929 if (local_err != NULL) {
2930 error_propagate(errp, local_err);
2932 return ret;
2935 static BlockReopenQueueEntry *find_parent_in_reopen_queue(BlockReopenQueue *q,
2936 BdrvChild *c)
2938 BlockReopenQueueEntry *entry;
2940 QSIMPLEQ_FOREACH(entry, q, entry) {
2941 BlockDriverState *bs = entry->state.bs;
2942 BdrvChild *child;
2944 QLIST_FOREACH(child, &bs->children, next) {
2945 if (child == c) {
2946 return entry;
2951 return NULL;
2954 static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs,
2955 uint64_t *perm, uint64_t *shared)
2957 BdrvChild *c;
2958 BlockReopenQueueEntry *parent;
2959 uint64_t cumulative_perms = 0;
2960 uint64_t cumulative_shared_perms = BLK_PERM_ALL;
2962 QLIST_FOREACH(c, &bs->parents, next_parent) {
2963 parent = find_parent_in_reopen_queue(q, c);
2964 if (!parent) {
2965 cumulative_perms |= c->perm;
2966 cumulative_shared_perms &= c->shared_perm;
2967 } else {
2968 uint64_t nperm, nshared;
2970 bdrv_child_perm(parent->state.bs, bs, c, c->role, q,
2971 parent->state.perm, parent->state.shared_perm,
2972 &nperm, &nshared);
2974 cumulative_perms |= nperm;
2975 cumulative_shared_perms &= nshared;
2978 *perm = cumulative_perms;
2979 *shared = cumulative_shared_perms;
2983 * Prepares a BlockDriverState for reopen. All changes are staged in the
2984 * 'opaque' field of the BDRVReopenState, which is used and allocated by
2985 * the block driver layer .bdrv_reopen_prepare()
2987 * bs is the BlockDriverState to reopen
2988 * flags are the new open flags
2989 * queue is the reopen queue
2991 * Returns 0 on success, non-zero on error. On error errp will be set
2992 * as well.
2994 * On failure, bdrv_reopen_abort() will be called to clean up any data.
2995 * It is the responsibility of the caller to then call the abort() or
2996 * commit() for any other BDS that have been left in a prepare() state
2999 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
3000 Error **errp)
3002 int ret = -1;
3003 Error *local_err = NULL;
3004 BlockDriver *drv;
3005 QemuOpts *opts;
3006 const char *value;
3007 bool read_only;
3009 assert(reopen_state != NULL);
3010 assert(reopen_state->bs->drv != NULL);
3011 drv = reopen_state->bs->drv;
3013 /* Process generic block layer options */
3014 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
3015 qemu_opts_absorb_qdict(opts, reopen_state->options, &local_err);
3016 if (local_err) {
3017 error_propagate(errp, local_err);
3018 ret = -EINVAL;
3019 goto error;
3022 update_flags_from_options(&reopen_state->flags, opts);
3024 /* node-name and driver must be unchanged. Put them back into the QDict, so
3025 * that they are checked at the end of this function. */
3026 value = qemu_opt_get(opts, "node-name");
3027 if (value) {
3028 qdict_put_str(reopen_state->options, "node-name", value);
3031 value = qemu_opt_get(opts, "driver");
3032 if (value) {
3033 qdict_put_str(reopen_state->options, "driver", value);
3036 /* If we are to stay read-only, do not allow permission change
3037 * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is
3038 * not set, or if the BDS still has copy_on_read enabled */
3039 read_only = !(reopen_state->flags & BDRV_O_RDWR);
3040 ret = bdrv_can_set_read_only(reopen_state->bs, read_only, true, &local_err);
3041 if (local_err) {
3042 error_propagate(errp, local_err);
3043 goto error;
3046 /* Calculate required permissions after reopening */
3047 bdrv_reopen_perm(queue, reopen_state->bs,
3048 &reopen_state->perm, &reopen_state->shared_perm);
3050 ret = bdrv_flush(reopen_state->bs);
3051 if (ret) {
3052 error_setg_errno(errp, -ret, "Error flushing drive");
3053 goto error;
3056 if (drv->bdrv_reopen_prepare) {
3057 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err);
3058 if (ret) {
3059 if (local_err != NULL) {
3060 error_propagate(errp, local_err);
3061 } else {
3062 error_setg(errp, "failed while preparing to reopen image '%s'",
3063 reopen_state->bs->filename);
3065 goto error;
3067 } else {
3068 /* It is currently mandatory to have a bdrv_reopen_prepare()
3069 * handler for each supported drv. */
3070 error_setg(errp, "Block format '%s' used by node '%s' "
3071 "does not support reopening files", drv->format_name,
3072 bdrv_get_device_or_node_name(reopen_state->bs));
3073 ret = -1;
3074 goto error;
3077 /* Options that are not handled are only okay if they are unchanged
3078 * compared to the old state. It is expected that some options are only
3079 * used for the initial open, but not reopen (e.g. filename) */
3080 if (qdict_size(reopen_state->options)) {
3081 const QDictEntry *entry = qdict_first(reopen_state->options);
3083 do {
3084 QObject *new = entry->value;
3085 QObject *old = qdict_get(reopen_state->bs->options, entry->key);
3088 * TODO: When using -drive to specify blockdev options, all values
3089 * will be strings; however, when using -blockdev, blockdev-add or
3090 * filenames using the json:{} pseudo-protocol, they will be
3091 * correctly typed.
3092 * In contrast, reopening options are (currently) always strings
3093 * (because you can only specify them through qemu-io; all other
3094 * callers do not specify any options).
3095 * Therefore, when using anything other than -drive to create a BDS,
3096 * this cannot detect non-string options as unchanged, because
3097 * qobject_is_equal() always returns false for objects of different
3098 * type. In the future, this should be remedied by correctly typing
3099 * all options. For now, this is not too big of an issue because
3100 * the user can simply omit options which cannot be changed anyway,
3101 * so they will stay unchanged.
3103 if (!qobject_is_equal(new, old)) {
3104 error_setg(errp, "Cannot change the option '%s'", entry->key);
3105 ret = -EINVAL;
3106 goto error;
3108 } while ((entry = qdict_next(reopen_state->options, entry)));
3111 ret = bdrv_check_perm(reopen_state->bs, queue, reopen_state->perm,
3112 reopen_state->shared_perm, NULL, errp);
3113 if (ret < 0) {
3114 goto error;
3117 ret = 0;
3119 error:
3120 qemu_opts_del(opts);
3121 return ret;
3125 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
3126 * makes them final by swapping the staging BlockDriverState contents into
3127 * the active BlockDriverState contents.
3129 void bdrv_reopen_commit(BDRVReopenState *reopen_state)
3131 BlockDriver *drv;
3132 BlockDriverState *bs;
3133 bool old_can_write, new_can_write;
3135 assert(reopen_state != NULL);
3136 bs = reopen_state->bs;
3137 drv = bs->drv;
3138 assert(drv != NULL);
3140 old_can_write =
3141 !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE);
3143 /* If there are any driver level actions to take */
3144 if (drv->bdrv_reopen_commit) {
3145 drv->bdrv_reopen_commit(reopen_state);
3148 /* set BDS specific flags now */
3149 QDECREF(bs->explicit_options);
3151 bs->explicit_options = reopen_state->explicit_options;
3152 bs->open_flags = reopen_state->flags;
3153 bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
3155 bdrv_refresh_limits(bs, NULL);
3157 bdrv_set_perm(reopen_state->bs, reopen_state->perm,
3158 reopen_state->shared_perm);
3160 new_can_write =
3161 !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE);
3162 if (!old_can_write && new_can_write && drv->bdrv_reopen_bitmaps_rw) {
3163 Error *local_err = NULL;
3164 if (drv->bdrv_reopen_bitmaps_rw(bs, &local_err) < 0) {
3165 /* This is not fatal, bitmaps just left read-only, so all following
3166 * writes will fail. User can remove read-only bitmaps to unblock
3167 * writes.
3169 error_reportf_err(local_err,
3170 "%s: Failed to make dirty bitmaps writable: ",
3171 bdrv_get_node_name(bs));
3177 * Abort the reopen, and delete and free the staged changes in
3178 * reopen_state
3180 void bdrv_reopen_abort(BDRVReopenState *reopen_state)
3182 BlockDriver *drv;
3184 assert(reopen_state != NULL);
3185 drv = reopen_state->bs->drv;
3186 assert(drv != NULL);
3188 if (drv->bdrv_reopen_abort) {
3189 drv->bdrv_reopen_abort(reopen_state);
3192 QDECREF(reopen_state->explicit_options);
3194 bdrv_abort_perm_update(reopen_state->bs);
3198 static void bdrv_close(BlockDriverState *bs)
3200 BdrvAioNotifier *ban, *ban_next;
3201 BdrvChild *child, *next;
3203 assert(!bs->job);
3204 assert(!bs->refcnt);
3206 bdrv_drained_begin(bs); /* complete I/O */
3207 bdrv_flush(bs);
3208 bdrv_drain(bs); /* in case flush left pending I/O */
3210 if (bs->drv) {
3211 bs->drv->bdrv_close(bs);
3212 bs->drv = NULL;
3215 bdrv_set_backing_hd(bs, NULL, &error_abort);
3217 if (bs->file != NULL) {
3218 bdrv_unref_child(bs, bs->file);
3219 bs->file = NULL;
3222 QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
3223 /* TODO Remove bdrv_unref() from drivers' close function and use
3224 * bdrv_unref_child() here */
3225 if (child->bs->inherits_from == bs) {
3226 child->bs->inherits_from = NULL;
3228 bdrv_detach_child(child);
3231 g_free(bs->opaque);
3232 bs->opaque = NULL;
3233 atomic_set(&bs->copy_on_read, 0);
3234 bs->backing_file[0] = '\0';
3235 bs->backing_format[0] = '\0';
3236 bs->total_sectors = 0;
3237 bs->encrypted = false;
3238 bs->sg = false;
3239 QDECREF(bs->options);
3240 QDECREF(bs->explicit_options);
3241 bs->options = NULL;
3242 bs->explicit_options = NULL;
3243 QDECREF(bs->full_open_options);
3244 bs->full_open_options = NULL;
3246 bdrv_release_named_dirty_bitmaps(bs);
3247 assert(QLIST_EMPTY(&bs->dirty_bitmaps));
3249 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
3250 g_free(ban);
3252 QLIST_INIT(&bs->aio_notifiers);
3253 bdrv_drained_end(bs);
3256 void bdrv_close_all(void)
3258 block_job_cancel_sync_all();
3259 nbd_export_close_all();
3261 /* Drop references from requests still in flight, such as canceled block
3262 * jobs whose AIO context has not been polled yet */
3263 bdrv_drain_all();
3265 blk_remove_all_bs();
3266 blockdev_close_all_bdrv_states();
3268 assert(QTAILQ_EMPTY(&all_bdrv_states));
3271 static bool should_update_child(BdrvChild *c, BlockDriverState *to)
3273 BdrvChild *to_c;
3275 if (c->role->stay_at_node) {
3276 return false;
3279 if (c->role == &child_backing) {
3280 /* If @from is a backing file of @to, ignore the child to avoid
3281 * creating a loop. We only want to change the pointer of other
3282 * parents. */
3283 QLIST_FOREACH(to_c, &to->children, next) {
3284 if (to_c == c) {
3285 break;
3288 if (to_c) {
3289 return false;
3293 return true;
3296 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
3297 Error **errp)
3299 BdrvChild *c, *next;
3300 GSList *list = NULL, *p;
3301 uint64_t old_perm, old_shared;
3302 uint64_t perm = 0, shared = BLK_PERM_ALL;
3303 int ret;
3305 assert(!atomic_read(&from->in_flight));
3306 assert(!atomic_read(&to->in_flight));
3308 /* Make sure that @from doesn't go away until we have successfully attached
3309 * all of its parents to @to. */
3310 bdrv_ref(from);
3312 /* Put all parents into @list and calculate their cumulative permissions */
3313 QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
3314 if (!should_update_child(c, to)) {
3315 continue;
3317 list = g_slist_prepend(list, c);
3318 perm |= c->perm;
3319 shared &= c->shared_perm;
3322 /* Check whether the required permissions can be granted on @to, ignoring
3323 * all BdrvChild in @list so that they can't block themselves. */
3324 ret = bdrv_check_update_perm(to, NULL, perm, shared, list, errp);
3325 if (ret < 0) {
3326 bdrv_abort_perm_update(to);
3327 goto out;
3330 /* Now actually perform the change. We performed the permission check for
3331 * all elements of @list at once, so set the permissions all at once at the
3332 * very end. */
3333 for (p = list; p != NULL; p = p->next) {
3334 c = p->data;
3336 bdrv_ref(to);
3337 bdrv_replace_child_noperm(c, to);
3338 bdrv_unref(from);
3341 bdrv_get_cumulative_perm(to, &old_perm, &old_shared);
3342 bdrv_set_perm(to, old_perm | perm, old_shared | shared);
3344 out:
3345 g_slist_free(list);
3346 bdrv_unref(from);
3350 * Add new bs contents at the top of an image chain while the chain is
3351 * live, while keeping required fields on the top layer.
3353 * This will modify the BlockDriverState fields, and swap contents
3354 * between bs_new and bs_top. Both bs_new and bs_top are modified.
3356 * bs_new must not be attached to a BlockBackend.
3358 * This function does not create any image files.
3360 * bdrv_append() takes ownership of a bs_new reference and unrefs it because
3361 * that's what the callers commonly need. bs_new will be referenced by the old
3362 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a
3363 * reference of its own, it must call bdrv_ref().
3365 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
3366 Error **errp)
3368 Error *local_err = NULL;
3370 bdrv_set_backing_hd(bs_new, bs_top, &local_err);
3371 if (local_err) {
3372 error_propagate(errp, local_err);
3373 goto out;
3376 bdrv_replace_node(bs_top, bs_new, &local_err);
3377 if (local_err) {
3378 error_propagate(errp, local_err);
3379 bdrv_set_backing_hd(bs_new, NULL, &error_abort);
3380 goto out;
3383 /* bs_new is now referenced by its new parents, we don't need the
3384 * additional reference any more. */
3385 out:
3386 bdrv_unref(bs_new);
3389 static void bdrv_delete(BlockDriverState *bs)
3391 assert(!bs->job);
3392 assert(bdrv_op_blocker_is_empty(bs));
3393 assert(!bs->refcnt);
3395 bdrv_close(bs);
3397 /* remove from list, if necessary */
3398 if (bs->node_name[0] != '\0') {
3399 QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list);
3401 QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list);
3403 g_free(bs);
3407 * Run consistency checks on an image
3409 * Returns 0 if the check could be completed (it doesn't mean that the image is
3410 * free of errors) or -errno when an internal error occurred. The results of the
3411 * check are stored in res.
3413 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix)
3415 if (bs->drv == NULL) {
3416 return -ENOMEDIUM;
3418 if (bs->drv->bdrv_check == NULL) {
3419 return -ENOTSUP;
3422 memset(res, 0, sizeof(*res));
3423 return bs->drv->bdrv_check(bs, res, fix);
3427 * Return values:
3428 * 0 - success
3429 * -EINVAL - backing format specified, but no file
3430 * -ENOSPC - can't update the backing file because no space is left in the
3431 * image file header
3432 * -ENOTSUP - format driver doesn't support changing the backing file
3434 int bdrv_change_backing_file(BlockDriverState *bs,
3435 const char *backing_file, const char *backing_fmt)
3437 BlockDriver *drv = bs->drv;
3438 int ret;
3440 if (!drv) {
3441 return -ENOMEDIUM;
3444 /* Backing file format doesn't make sense without a backing file */
3445 if (backing_fmt && !backing_file) {
3446 return -EINVAL;
3449 if (drv->bdrv_change_backing_file != NULL) {
3450 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
3451 } else {
3452 ret = -ENOTSUP;
3455 if (ret == 0) {
3456 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
3457 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
3459 return ret;
3463 * Finds the image layer in the chain that has 'bs' as its backing file.
3465 * active is the current topmost image.
3467 * Returns NULL if bs is not found in active's image chain,
3468 * or if active == bs.
3470 * Returns the bottommost base image if bs == NULL.
3472 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
3473 BlockDriverState *bs)
3475 while (active && bs != backing_bs(active)) {
3476 active = backing_bs(active);
3479 return active;
3482 /* Given a BDS, searches for the base layer. */
3483 BlockDriverState *bdrv_find_base(BlockDriverState *bs)
3485 return bdrv_find_overlay(bs, NULL);
3489 * Drops images above 'base' up to and including 'top', and sets the image
3490 * above 'top' to have base as its backing file.
3492 * Requires that the overlay to 'top' is opened r/w, so that the backing file
3493 * information in 'bs' can be properly updated.
3495 * E.g., this will convert the following chain:
3496 * bottom <- base <- intermediate <- top <- active
3498 * to
3500 * bottom <- base <- active
3502 * It is allowed for bottom==base, in which case it converts:
3504 * base <- intermediate <- top <- active
3506 * to
3508 * base <- active
3510 * If backing_file_str is non-NULL, it will be used when modifying top's
3511 * overlay image metadata.
3513 * Error conditions:
3514 * if active == top, that is considered an error
3517 int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
3518 const char *backing_file_str)
3520 BdrvChild *c, *next;
3521 Error *local_err = NULL;
3522 int ret = -EIO;
3524 bdrv_ref(top);
3526 if (!top->drv || !base->drv) {
3527 goto exit;
3530 /* Make sure that base is in the backing chain of top */
3531 if (!bdrv_chain_contains(top, base)) {
3532 goto exit;
3535 /* success - we can delete the intermediate states, and link top->base */
3536 /* TODO Check graph modification op blockers (BLK_PERM_GRAPH_MOD) once
3537 * we've figured out how they should work. */
3538 backing_file_str = backing_file_str ? backing_file_str : base->filename;
3540 QLIST_FOREACH_SAFE(c, &top->parents, next_parent, next) {
3541 /* Check whether we are allowed to switch c from top to base */
3542 GSList *ignore_children = g_slist_prepend(NULL, c);
3543 bdrv_check_update_perm(base, NULL, c->perm, c->shared_perm,
3544 ignore_children, &local_err);
3545 if (local_err) {
3546 ret = -EPERM;
3547 error_report_err(local_err);
3548 goto exit;
3550 g_slist_free(ignore_children);
3552 /* If so, update the backing file path in the image file */
3553 if (c->role->update_filename) {
3554 ret = c->role->update_filename(c, base, backing_file_str,
3555 &local_err);
3556 if (ret < 0) {
3557 bdrv_abort_perm_update(base);
3558 error_report_err(local_err);
3559 goto exit;
3563 /* Do the actual switch in the in-memory graph.
3564 * Completes bdrv_check_update_perm() transaction internally. */
3565 bdrv_ref(base);
3566 bdrv_replace_child(c, base);
3567 bdrv_unref(top);
3570 ret = 0;
3571 exit:
3572 bdrv_unref(top);
3573 return ret;
3577 * Truncate file to 'offset' bytes (needed only for file protocols)
3579 int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc,
3580 Error **errp)
3582 BlockDriverState *bs = child->bs;
3583 BlockDriver *drv = bs->drv;
3584 int ret;
3586 assert(child->perm & BLK_PERM_RESIZE);
3588 /* if bs->drv == NULL, bs is closed, so there's nothing to do here */
3589 if (!drv) {
3590 error_setg(errp, "No medium inserted");
3591 return -ENOMEDIUM;
3593 if (!drv->bdrv_truncate) {
3594 if (bs->file && drv->is_filter) {
3595 return bdrv_truncate(bs->file, offset, prealloc, errp);
3597 error_setg(errp, "Image format driver does not support resize");
3598 return -ENOTSUP;
3600 if (bs->read_only) {
3601 error_setg(errp, "Image is read-only");
3602 return -EACCES;
3605 assert(!(bs->open_flags & BDRV_O_INACTIVE));
3607 ret = drv->bdrv_truncate(bs, offset, prealloc, errp);
3608 if (ret < 0) {
3609 return ret;
3611 ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
3612 if (ret < 0) {
3613 error_setg_errno(errp, -ret, "Could not refresh total sector count");
3614 } else {
3615 offset = bs->total_sectors * BDRV_SECTOR_SIZE;
3617 bdrv_dirty_bitmap_truncate(bs, offset);
3618 bdrv_parent_cb_resize(bs);
3619 atomic_inc(&bs->write_gen);
3620 return ret;
3624 * Length of a allocated file in bytes. Sparse files are counted by actual
3625 * allocated space. Return < 0 if error or unknown.
3627 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs)
3629 BlockDriver *drv = bs->drv;
3630 if (!drv) {
3631 return -ENOMEDIUM;
3633 if (drv->bdrv_get_allocated_file_size) {
3634 return drv->bdrv_get_allocated_file_size(bs);
3636 if (bs->file) {
3637 return bdrv_get_allocated_file_size(bs->file->bs);
3639 return -ENOTSUP;
3643 * bdrv_measure:
3644 * @drv: Format driver
3645 * @opts: Creation options for new image
3646 * @in_bs: Existing image containing data for new image (may be NULL)
3647 * @errp: Error object
3648 * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo())
3649 * or NULL on error
3651 * Calculate file size required to create a new image.
3653 * If @in_bs is given then space for allocated clusters and zero clusters
3654 * from that image are included in the calculation. If @opts contains a
3655 * backing file that is shared by @in_bs then backing clusters may be omitted
3656 * from the calculation.
3658 * If @in_bs is NULL then the calculation includes no allocated clusters
3659 * unless a preallocation option is given in @opts.
3661 * Note that @in_bs may use a different BlockDriver from @drv.
3663 * If an error occurs the @errp pointer is set.
3665 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
3666 BlockDriverState *in_bs, Error **errp)
3668 if (!drv->bdrv_measure) {
3669 error_setg(errp, "Block driver '%s' does not support size measurement",
3670 drv->format_name);
3671 return NULL;
3674 return drv->bdrv_measure(opts, in_bs, errp);
3678 * Return number of sectors on success, -errno on error.
3680 int64_t bdrv_nb_sectors(BlockDriverState *bs)
3682 BlockDriver *drv = bs->drv;
3684 if (!drv)
3685 return -ENOMEDIUM;
3687 if (drv->has_variable_length) {
3688 int ret = refresh_total_sectors(bs, bs->total_sectors);
3689 if (ret < 0) {
3690 return ret;
3693 return bs->total_sectors;
3697 * Return length in bytes on success, -errno on error.
3698 * The length is always a multiple of BDRV_SECTOR_SIZE.
3700 int64_t bdrv_getlength(BlockDriverState *bs)
3702 int64_t ret = bdrv_nb_sectors(bs);
3704 ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret;
3705 return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE;
3708 /* return 0 as number of sectors if no device present or error */
3709 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
3711 int64_t nb_sectors = bdrv_nb_sectors(bs);
3713 *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors;
3716 bool bdrv_is_sg(BlockDriverState *bs)
3718 return bs->sg;
3721 bool bdrv_is_encrypted(BlockDriverState *bs)
3723 if (bs->backing && bs->backing->bs->encrypted) {
3724 return true;
3726 return bs->encrypted;
3729 const char *bdrv_get_format_name(BlockDriverState *bs)
3731 return bs->drv ? bs->drv->format_name : NULL;
3734 static int qsort_strcmp(const void *a, const void *b)
3736 return strcmp(*(char *const *)a, *(char *const *)b);
3739 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
3740 void *opaque)
3742 BlockDriver *drv;
3743 int count = 0;
3744 int i;
3745 const char **formats = NULL;
3747 QLIST_FOREACH(drv, &bdrv_drivers, list) {
3748 if (drv->format_name) {
3749 bool found = false;
3750 int i = count;
3751 while (formats && i && !found) {
3752 found = !strcmp(formats[--i], drv->format_name);
3755 if (!found) {
3756 formats = g_renew(const char *, formats, count + 1);
3757 formats[count++] = drv->format_name;
3762 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); i++) {
3763 const char *format_name = block_driver_modules[i].format_name;
3765 if (format_name) {
3766 bool found = false;
3767 int j = count;
3769 while (formats && j && !found) {
3770 found = !strcmp(formats[--j], format_name);
3773 if (!found) {
3774 formats = g_renew(const char *, formats, count + 1);
3775 formats[count++] = format_name;
3780 qsort(formats, count, sizeof(formats[0]), qsort_strcmp);
3782 for (i = 0; i < count; i++) {
3783 it(opaque, formats[i]);
3786 g_free(formats);
3789 /* This function is to find a node in the bs graph */
3790 BlockDriverState *bdrv_find_node(const char *node_name)
3792 BlockDriverState *bs;
3794 assert(node_name);
3796 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
3797 if (!strcmp(node_name, bs->node_name)) {
3798 return bs;
3801 return NULL;
3804 /* Put this QMP function here so it can access the static graph_bdrv_states. */
3805 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp)
3807 BlockDeviceInfoList *list, *entry;
3808 BlockDriverState *bs;
3810 list = NULL;
3811 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
3812 BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, errp);
3813 if (!info) {
3814 qapi_free_BlockDeviceInfoList(list);
3815 return NULL;
3817 entry = g_malloc0(sizeof(*entry));
3818 entry->value = info;
3819 entry->next = list;
3820 list = entry;
3823 return list;
3826 BlockDriverState *bdrv_lookup_bs(const char *device,
3827 const char *node_name,
3828 Error **errp)
3830 BlockBackend *blk;
3831 BlockDriverState *bs;
3833 if (device) {
3834 blk = blk_by_name(device);
3836 if (blk) {
3837 bs = blk_bs(blk);
3838 if (!bs) {
3839 error_setg(errp, "Device '%s' has no medium", device);
3842 return bs;
3846 if (node_name) {
3847 bs = bdrv_find_node(node_name);
3849 if (bs) {
3850 return bs;
3854 error_setg(errp, "Cannot find device=%s nor node_name=%s",
3855 device ? device : "",
3856 node_name ? node_name : "");
3857 return NULL;
3860 /* If 'base' is in the same chain as 'top', return true. Otherwise,
3861 * return false. If either argument is NULL, return false. */
3862 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base)
3864 while (top && top != base) {
3865 top = backing_bs(top);
3868 return top != NULL;
3871 BlockDriverState *bdrv_next_node(BlockDriverState *bs)
3873 if (!bs) {
3874 return QTAILQ_FIRST(&graph_bdrv_states);
3876 return QTAILQ_NEXT(bs, node_list);
3879 const char *bdrv_get_node_name(const BlockDriverState *bs)
3881 return bs->node_name;
3884 const char *bdrv_get_parent_name(const BlockDriverState *bs)
3886 BdrvChild *c;
3887 const char *name;
3889 /* If multiple parents have a name, just pick the first one. */
3890 QLIST_FOREACH(c, &bs->parents, next_parent) {
3891 if (c->role->get_name) {
3892 name = c->role->get_name(c);
3893 if (name && *name) {
3894 return name;
3899 return NULL;
3902 /* TODO check what callers really want: bs->node_name or blk_name() */
3903 const char *bdrv_get_device_name(const BlockDriverState *bs)
3905 return bdrv_get_parent_name(bs) ?: "";
3908 /* This can be used to identify nodes that might not have a device
3909 * name associated. Since node and device names live in the same
3910 * namespace, the result is unambiguous. The exception is if both are
3911 * absent, then this returns an empty (non-null) string. */
3912 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs)
3914 return bdrv_get_parent_name(bs) ?: bs->node_name;
3917 int bdrv_get_flags(BlockDriverState *bs)
3919 return bs->open_flags;
3922 int bdrv_has_zero_init_1(BlockDriverState *bs)
3924 return 1;
3927 int bdrv_has_zero_init(BlockDriverState *bs)
3929 if (!bs->drv) {
3930 return 0;
3933 /* If BS is a copy on write image, it is initialized to
3934 the contents of the base image, which may not be zeroes. */
3935 if (bs->backing) {
3936 return 0;
3938 if (bs->drv->bdrv_has_zero_init) {
3939 return bs->drv->bdrv_has_zero_init(bs);
3941 if (bs->file && bs->drv->is_filter) {
3942 return bdrv_has_zero_init(bs->file->bs);
3945 /* safe default */
3946 return 0;
3949 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs)
3951 BlockDriverInfo bdi;
3953 if (bs->backing) {
3954 return false;
3957 if (bdrv_get_info(bs, &bdi) == 0) {
3958 return bdi.unallocated_blocks_are_zero;
3961 return false;
3964 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
3966 BlockDriverInfo bdi;
3968 if (!(bs->open_flags & BDRV_O_UNMAP)) {
3969 return false;
3972 if (bdrv_get_info(bs, &bdi) == 0) {
3973 return bdi.can_write_zeroes_with_unmap;
3976 return false;
3979 const char *bdrv_get_encrypted_filename(BlockDriverState *bs)
3981 if (bs->backing && bs->backing->bs->encrypted)
3982 return bs->backing_file;
3983 else if (bs->encrypted)
3984 return bs->filename;
3985 else
3986 return NULL;
3989 void bdrv_get_backing_filename(BlockDriverState *bs,
3990 char *filename, int filename_size)
3992 pstrcpy(filename, filename_size, bs->backing_file);
3995 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
3997 BlockDriver *drv = bs->drv;
3998 /* if bs->drv == NULL, bs is closed, so there's nothing to do here */
3999 if (!drv) {
4000 return -ENOMEDIUM;
4002 if (!drv->bdrv_get_info) {
4003 if (bs->file && drv->is_filter) {
4004 return bdrv_get_info(bs->file->bs, bdi);
4006 return -ENOTSUP;
4008 memset(bdi, 0, sizeof(*bdi));
4009 return drv->bdrv_get_info(bs, bdi);
4012 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs)
4014 BlockDriver *drv = bs->drv;
4015 if (drv && drv->bdrv_get_specific_info) {
4016 return drv->bdrv_get_specific_info(bs);
4018 return NULL;
4021 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event)
4023 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
4024 return;
4027 bs->drv->bdrv_debug_event(bs, event);
4030 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
4031 const char *tag)
4033 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) {
4034 bs = bs->file ? bs->file->bs : NULL;
4037 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) {
4038 return bs->drv->bdrv_debug_breakpoint(bs, event, tag);
4041 return -ENOTSUP;
4044 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag)
4046 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) {
4047 bs = bs->file ? bs->file->bs : NULL;
4050 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) {
4051 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag);
4054 return -ENOTSUP;
4057 int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
4059 while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) {
4060 bs = bs->file ? bs->file->bs : NULL;
4063 if (bs && bs->drv && bs->drv->bdrv_debug_resume) {
4064 return bs->drv->bdrv_debug_resume(bs, tag);
4067 return -ENOTSUP;
4070 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag)
4072 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) {
4073 bs = bs->file ? bs->file->bs : NULL;
4076 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) {
4077 return bs->drv->bdrv_debug_is_suspended(bs, tag);
4080 return false;
4083 /* backing_file can either be relative, or absolute, or a protocol. If it is
4084 * relative, it must be relative to the chain. So, passing in bs->filename
4085 * from a BDS as backing_file should not be done, as that may be relative to
4086 * the CWD rather than the chain. */
4087 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
4088 const char *backing_file)
4090 char *filename_full = NULL;
4091 char *backing_file_full = NULL;
4092 char *filename_tmp = NULL;
4093 int is_protocol = 0;
4094 BlockDriverState *curr_bs = NULL;
4095 BlockDriverState *retval = NULL;
4096 Error *local_error = NULL;
4098 if (!bs || !bs->drv || !backing_file) {
4099 return NULL;
4102 filename_full = g_malloc(PATH_MAX);
4103 backing_file_full = g_malloc(PATH_MAX);
4104 filename_tmp = g_malloc(PATH_MAX);
4106 is_protocol = path_has_protocol(backing_file);
4108 for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) {
4110 /* If either of the filename paths is actually a protocol, then
4111 * compare unmodified paths; otherwise make paths relative */
4112 if (is_protocol || path_has_protocol(curr_bs->backing_file)) {
4113 if (strcmp(backing_file, curr_bs->backing_file) == 0) {
4114 retval = curr_bs->backing->bs;
4115 break;
4117 /* Also check against the full backing filename for the image */
4118 bdrv_get_full_backing_filename(curr_bs, backing_file_full, PATH_MAX,
4119 &local_error);
4120 if (local_error == NULL) {
4121 if (strcmp(backing_file, backing_file_full) == 0) {
4122 retval = curr_bs->backing->bs;
4123 break;
4125 } else {
4126 error_free(local_error);
4127 local_error = NULL;
4129 } else {
4130 /* If not an absolute filename path, make it relative to the current
4131 * image's filename path */
4132 path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
4133 backing_file);
4135 /* We are going to compare absolute pathnames */
4136 if (!realpath(filename_tmp, filename_full)) {
4137 continue;
4140 /* We need to make sure the backing filename we are comparing against
4141 * is relative to the current image filename (or absolute) */
4142 path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
4143 curr_bs->backing_file);
4145 if (!realpath(filename_tmp, backing_file_full)) {
4146 continue;
4149 if (strcmp(backing_file_full, filename_full) == 0) {
4150 retval = curr_bs->backing->bs;
4151 break;
4156 g_free(filename_full);
4157 g_free(backing_file_full);
4158 g_free(filename_tmp);
4159 return retval;
4162 void bdrv_init(void)
4164 module_call_init(MODULE_INIT_BLOCK);
4167 void bdrv_init_with_whitelist(void)
4169 use_bdrv_whitelist = 1;
4170 bdrv_init();
4173 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
4175 BdrvChild *child, *parent;
4176 uint64_t perm, shared_perm;
4177 Error *local_err = NULL;
4178 int ret;
4180 if (!bs->drv) {
4181 return;
4184 if (!(bs->open_flags & BDRV_O_INACTIVE)) {
4185 return;
4188 QLIST_FOREACH(child, &bs->children, next) {
4189 bdrv_invalidate_cache(child->bs, &local_err);
4190 if (local_err) {
4191 error_propagate(errp, local_err);
4192 return;
4197 * Update permissions, they may differ for inactive nodes.
4199 * Note that the required permissions of inactive images are always a
4200 * subset of the permissions required after activating the image. This
4201 * allows us to just get the permissions upfront without restricting
4202 * drv->bdrv_invalidate_cache().
4204 * It also means that in error cases, we don't have to try and revert to
4205 * the old permissions (which is an operation that could fail, too). We can
4206 * just keep the extended permissions for the next time that an activation
4207 * of the image is tried.
4209 bs->open_flags &= ~BDRV_O_INACTIVE;
4210 bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
4211 ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, &local_err);
4212 if (ret < 0) {
4213 bs->open_flags |= BDRV_O_INACTIVE;
4214 error_propagate(errp, local_err);
4215 return;
4217 bdrv_set_perm(bs, perm, shared_perm);
4219 if (bs->drv->bdrv_invalidate_cache) {
4220 bs->drv->bdrv_invalidate_cache(bs, &local_err);
4221 if (local_err) {
4222 bs->open_flags |= BDRV_O_INACTIVE;
4223 error_propagate(errp, local_err);
4224 return;
4228 ret = refresh_total_sectors(bs, bs->total_sectors);
4229 if (ret < 0) {
4230 bs->open_flags |= BDRV_O_INACTIVE;
4231 error_setg_errno(errp, -ret, "Could not refresh total sector count");
4232 return;
4235 QLIST_FOREACH(parent, &bs->parents, next_parent) {
4236 if (parent->role->activate) {
4237 parent->role->activate(parent, &local_err);
4238 if (local_err) {
4239 error_propagate(errp, local_err);
4240 return;
4246 void bdrv_invalidate_cache_all(Error **errp)
4248 BlockDriverState *bs;
4249 Error *local_err = NULL;
4250 BdrvNextIterator it;
4252 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
4253 AioContext *aio_context = bdrv_get_aio_context(bs);
4255 aio_context_acquire(aio_context);
4256 bdrv_invalidate_cache(bs, &local_err);
4257 aio_context_release(aio_context);
4258 if (local_err) {
4259 error_propagate(errp, local_err);
4260 bdrv_next_cleanup(&it);
4261 return;
4266 static int bdrv_inactivate_recurse(BlockDriverState *bs,
4267 bool setting_flag)
4269 BdrvChild *child, *parent;
4270 int ret;
4272 if (!bs->drv) {
4273 return -ENOMEDIUM;
4276 if (!setting_flag && bs->drv->bdrv_inactivate) {
4277 ret = bs->drv->bdrv_inactivate(bs);
4278 if (ret < 0) {
4279 return ret;
4283 if (setting_flag && !(bs->open_flags & BDRV_O_INACTIVE)) {
4284 uint64_t perm, shared_perm;
4286 QLIST_FOREACH(parent, &bs->parents, next_parent) {
4287 if (parent->role->inactivate) {
4288 ret = parent->role->inactivate(parent);
4289 if (ret < 0) {
4290 return ret;
4295 bs->open_flags |= BDRV_O_INACTIVE;
4297 /* Update permissions, they may differ for inactive nodes */
4298 bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
4299 bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, &error_abort);
4300 bdrv_set_perm(bs, perm, shared_perm);
4303 QLIST_FOREACH(child, &bs->children, next) {
4304 ret = bdrv_inactivate_recurse(child->bs, setting_flag);
4305 if (ret < 0) {
4306 return ret;
4310 /* At this point persistent bitmaps should be already stored by the format
4311 * driver */
4312 bdrv_release_persistent_dirty_bitmaps(bs);
4314 return 0;
4317 int bdrv_inactivate_all(void)
4319 BlockDriverState *bs = NULL;
4320 BdrvNextIterator it;
4321 int ret = 0;
4322 int pass;
4323 GSList *aio_ctxs = NULL, *ctx;
4325 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
4326 AioContext *aio_context = bdrv_get_aio_context(bs);
4328 if (!g_slist_find(aio_ctxs, aio_context)) {
4329 aio_ctxs = g_slist_prepend(aio_ctxs, aio_context);
4330 aio_context_acquire(aio_context);
4334 /* We do two passes of inactivation. The first pass calls to drivers'
4335 * .bdrv_inactivate callbacks recursively so all cache is flushed to disk;
4336 * the second pass sets the BDRV_O_INACTIVE flag so that no further write
4337 * is allowed. */
4338 for (pass = 0; pass < 2; pass++) {
4339 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
4340 ret = bdrv_inactivate_recurse(bs, pass);
4341 if (ret < 0) {
4342 bdrv_next_cleanup(&it);
4343 goto out;
4348 out:
4349 for (ctx = aio_ctxs; ctx != NULL; ctx = ctx->next) {
4350 AioContext *aio_context = ctx->data;
4351 aio_context_release(aio_context);
4353 g_slist_free(aio_ctxs);
4355 return ret;
4358 /**************************************************************/
4359 /* removable device support */
4362 * Return TRUE if the media is present
4364 bool bdrv_is_inserted(BlockDriverState *bs)
4366 BlockDriver *drv = bs->drv;
4367 BdrvChild *child;
4369 if (!drv) {
4370 return false;
4372 if (drv->bdrv_is_inserted) {
4373 return drv->bdrv_is_inserted(bs);
4375 QLIST_FOREACH(child, &bs->children, next) {
4376 if (!bdrv_is_inserted(child->bs)) {
4377 return false;
4380 return true;
4384 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
4386 void bdrv_eject(BlockDriverState *bs, bool eject_flag)
4388 BlockDriver *drv = bs->drv;
4390 if (drv && drv->bdrv_eject) {
4391 drv->bdrv_eject(bs, eject_flag);
4396 * Lock or unlock the media (if it is locked, the user won't be able
4397 * to eject it manually).
4399 void bdrv_lock_medium(BlockDriverState *bs, bool locked)
4401 BlockDriver *drv = bs->drv;
4403 trace_bdrv_lock_medium(bs, locked);
4405 if (drv && drv->bdrv_lock_medium) {
4406 drv->bdrv_lock_medium(bs, locked);
4410 /* Get a reference to bs */
4411 void bdrv_ref(BlockDriverState *bs)
4413 bs->refcnt++;
4416 /* Release a previously grabbed reference to bs.
4417 * If after releasing, reference count is zero, the BlockDriverState is
4418 * deleted. */
4419 void bdrv_unref(BlockDriverState *bs)
4421 if (!bs) {
4422 return;
4424 assert(bs->refcnt > 0);
4425 if (--bs->refcnt == 0) {
4426 bdrv_delete(bs);
4430 struct BdrvOpBlocker {
4431 Error *reason;
4432 QLIST_ENTRY(BdrvOpBlocker) list;
4435 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp)
4437 BdrvOpBlocker *blocker;
4438 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
4439 if (!QLIST_EMPTY(&bs->op_blockers[op])) {
4440 blocker = QLIST_FIRST(&bs->op_blockers[op]);
4441 error_propagate(errp, error_copy(blocker->reason));
4442 error_prepend(errp, "Node '%s' is busy: ",
4443 bdrv_get_device_or_node_name(bs));
4444 return true;
4446 return false;
4449 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason)
4451 BdrvOpBlocker *blocker;
4452 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
4454 blocker = g_new0(BdrvOpBlocker, 1);
4455 blocker->reason = reason;
4456 QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list);
4459 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason)
4461 BdrvOpBlocker *blocker, *next;
4462 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
4463 QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) {
4464 if (blocker->reason == reason) {
4465 QLIST_REMOVE(blocker, list);
4466 g_free(blocker);
4471 void bdrv_op_block_all(BlockDriverState *bs, Error *reason)
4473 int i;
4474 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
4475 bdrv_op_block(bs, i, reason);
4479 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason)
4481 int i;
4482 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
4483 bdrv_op_unblock(bs, i, reason);
4487 bool bdrv_op_blocker_is_empty(BlockDriverState *bs)
4489 int i;
4491 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
4492 if (!QLIST_EMPTY(&bs->op_blockers[i])) {
4493 return false;
4496 return true;
4499 void bdrv_img_create(const char *filename, const char *fmt,
4500 const char *base_filename, const char *base_fmt,
4501 char *options, uint64_t img_size, int flags, bool quiet,
4502 Error **errp)
4504 QemuOptsList *create_opts = NULL;
4505 QemuOpts *opts = NULL;
4506 const char *backing_fmt, *backing_file;
4507 int64_t size;
4508 BlockDriver *drv, *proto_drv;
4509 Error *local_err = NULL;
4510 int ret = 0;
4512 /* Find driver and parse its options */
4513 drv = bdrv_find_format(fmt);
4514 if (!drv) {
4515 error_setg(errp, "Unknown file format '%s'", fmt);
4516 return;
4519 proto_drv = bdrv_find_protocol(filename, true, errp);
4520 if (!proto_drv) {
4521 return;
4524 if (!drv->create_opts) {
4525 error_setg(errp, "Format driver '%s' does not support image creation",
4526 drv->format_name);
4527 return;
4530 if (!proto_drv->create_opts) {
4531 error_setg(errp, "Protocol driver '%s' does not support image creation",
4532 proto_drv->format_name);
4533 return;
4536 create_opts = qemu_opts_append(create_opts, drv->create_opts);
4537 create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
4539 /* Create parameter list with default values */
4540 opts = qemu_opts_create(create_opts, NULL, 0, &error_abort);
4541 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, img_size, &error_abort);
4543 /* Parse -o options */
4544 if (options) {
4545 qemu_opts_do_parse(opts, options, NULL, &local_err);
4546 if (local_err) {
4547 error_report_err(local_err);
4548 local_err = NULL;
4549 error_setg(errp, "Invalid options for file format '%s'", fmt);
4550 goto out;
4554 if (base_filename) {
4555 qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename, &local_err);
4556 if (local_err) {
4557 error_setg(errp, "Backing file not supported for file format '%s'",
4558 fmt);
4559 goto out;
4563 if (base_fmt) {
4564 qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt, &local_err);
4565 if (local_err) {
4566 error_setg(errp, "Backing file format not supported for file "
4567 "format '%s'", fmt);
4568 goto out;
4572 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
4573 if (backing_file) {
4574 if (!strcmp(filename, backing_file)) {
4575 error_setg(errp, "Error: Trying to create an image with the "
4576 "same filename as the backing file");
4577 goto out;
4581 backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
4583 /* The size for the image must always be specified, unless we have a backing
4584 * file and we have not been forbidden from opening it. */
4585 size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, img_size);
4586 if (backing_file && !(flags & BDRV_O_NO_BACKING)) {
4587 BlockDriverState *bs;
4588 char *full_backing = g_new0(char, PATH_MAX);
4589 int back_flags;
4590 QDict *backing_options = NULL;
4592 bdrv_get_full_backing_filename_from_filename(filename, backing_file,
4593 full_backing, PATH_MAX,
4594 &local_err);
4595 if (local_err) {
4596 g_free(full_backing);
4597 goto out;
4600 /* backing files always opened read-only */
4601 back_flags = flags;
4602 back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
4604 if (backing_fmt) {
4605 backing_options = qdict_new();
4606 qdict_put_str(backing_options, "driver", backing_fmt);
4609 bs = bdrv_open(full_backing, NULL, backing_options, back_flags,
4610 &local_err);
4611 g_free(full_backing);
4612 if (!bs && size != -1) {
4613 /* Couldn't open BS, but we have a size, so it's nonfatal */
4614 warn_reportf_err(local_err,
4615 "Could not verify backing image. "
4616 "This may become an error in future versions.\n");
4617 local_err = NULL;
4618 } else if (!bs) {
4619 /* Couldn't open bs, do not have size */
4620 error_append_hint(&local_err,
4621 "Could not open backing image to determine size.\n");
4622 goto out;
4623 } else {
4624 if (size == -1) {
4625 /* Opened BS, have no size */
4626 size = bdrv_getlength(bs);
4627 if (size < 0) {
4628 error_setg_errno(errp, -size, "Could not get size of '%s'",
4629 backing_file);
4630 bdrv_unref(bs);
4631 goto out;
4633 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort);
4635 bdrv_unref(bs);
4637 } /* (backing_file && !(flags & BDRV_O_NO_BACKING)) */
4639 if (size == -1) {
4640 error_setg(errp, "Image creation needs a size parameter");
4641 goto out;
4644 if (!quiet) {
4645 printf("Formatting '%s', fmt=%s ", filename, fmt);
4646 qemu_opts_print(opts, " ");
4647 puts("");
4650 ret = bdrv_create(drv, filename, opts, &local_err);
4652 if (ret == -EFBIG) {
4653 /* This is generally a better message than whatever the driver would
4654 * deliver (especially because of the cluster_size_hint), since that
4655 * is most probably not much different from "image too large". */
4656 const char *cluster_size_hint = "";
4657 if (qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 0)) {
4658 cluster_size_hint = " (try using a larger cluster size)";
4660 error_setg(errp, "The image size is too large for file format '%s'"
4661 "%s", fmt, cluster_size_hint);
4662 error_free(local_err);
4663 local_err = NULL;
4666 out:
4667 qemu_opts_del(opts);
4668 qemu_opts_free(create_opts);
4669 error_propagate(errp, local_err);
4672 AioContext *bdrv_get_aio_context(BlockDriverState *bs)
4674 return bs->aio_context;
4677 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co)
4679 aio_co_enter(bdrv_get_aio_context(bs), co);
4682 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban)
4684 QLIST_REMOVE(ban, list);
4685 g_free(ban);
4688 void bdrv_detach_aio_context(BlockDriverState *bs)
4690 BdrvAioNotifier *baf, *baf_tmp;
4691 BdrvChild *child;
4693 if (!bs->drv) {
4694 return;
4697 assert(!bs->walking_aio_notifiers);
4698 bs->walking_aio_notifiers = true;
4699 QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) {
4700 if (baf->deleted) {
4701 bdrv_do_remove_aio_context_notifier(baf);
4702 } else {
4703 baf->detach_aio_context(baf->opaque);
4706 /* Never mind iterating again to check for ->deleted. bdrv_close() will
4707 * remove remaining aio notifiers if we aren't called again.
4709 bs->walking_aio_notifiers = false;
4711 if (bs->drv->bdrv_detach_aio_context) {
4712 bs->drv->bdrv_detach_aio_context(bs);
4714 QLIST_FOREACH(child, &bs->children, next) {
4715 bdrv_detach_aio_context(child->bs);
4718 bs->aio_context = NULL;
4721 void bdrv_attach_aio_context(BlockDriverState *bs,
4722 AioContext *new_context)
4724 BdrvAioNotifier *ban, *ban_tmp;
4725 BdrvChild *child;
4727 if (!bs->drv) {
4728 return;
4731 bs->aio_context = new_context;
4733 QLIST_FOREACH(child, &bs->children, next) {
4734 bdrv_attach_aio_context(child->bs, new_context);
4736 if (bs->drv->bdrv_attach_aio_context) {
4737 bs->drv->bdrv_attach_aio_context(bs, new_context);
4740 assert(!bs->walking_aio_notifiers);
4741 bs->walking_aio_notifiers = true;
4742 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_tmp) {
4743 if (ban->deleted) {
4744 bdrv_do_remove_aio_context_notifier(ban);
4745 } else {
4746 ban->attached_aio_context(new_context, ban->opaque);
4749 bs->walking_aio_notifiers = false;
4752 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
4754 AioContext *ctx = bdrv_get_aio_context(bs);
4756 aio_disable_external(ctx);
4757 bdrv_parent_drained_begin(bs);
4758 bdrv_drain(bs); /* ensure there are no in-flight requests */
4760 while (aio_poll(ctx, false)) {
4761 /* wait for all bottom halves to execute */
4764 bdrv_detach_aio_context(bs);
4766 /* This function executes in the old AioContext so acquire the new one in
4767 * case it runs in a different thread.
4769 aio_context_acquire(new_context);
4770 bdrv_attach_aio_context(bs, new_context);
4771 bdrv_parent_drained_end(bs);
4772 aio_enable_external(ctx);
4773 aio_context_release(new_context);
4776 void bdrv_add_aio_context_notifier(BlockDriverState *bs,
4777 void (*attached_aio_context)(AioContext *new_context, void *opaque),
4778 void (*detach_aio_context)(void *opaque), void *opaque)
4780 BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1);
4781 *ban = (BdrvAioNotifier){
4782 .attached_aio_context = attached_aio_context,
4783 .detach_aio_context = detach_aio_context,
4784 .opaque = opaque
4787 QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list);
4790 void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
4791 void (*attached_aio_context)(AioContext *,
4792 void *),
4793 void (*detach_aio_context)(void *),
4794 void *opaque)
4796 BdrvAioNotifier *ban, *ban_next;
4798 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
4799 if (ban->attached_aio_context == attached_aio_context &&
4800 ban->detach_aio_context == detach_aio_context &&
4801 ban->opaque == opaque &&
4802 ban->deleted == false)
4804 if (bs->walking_aio_notifiers) {
4805 ban->deleted = true;
4806 } else {
4807 bdrv_do_remove_aio_context_notifier(ban);
4809 return;
4813 abort();
4816 int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts,
4817 BlockDriverAmendStatusCB *status_cb, void *cb_opaque)
4819 if (!bs->drv) {
4820 return -ENOMEDIUM;
4822 if (!bs->drv->bdrv_amend_options) {
4823 return -ENOTSUP;
4825 return bs->drv->bdrv_amend_options(bs, opts, status_cb, cb_opaque);
4828 /* This function will be called by the bdrv_recurse_is_first_non_filter method
4829 * of block filter and by bdrv_is_first_non_filter.
4830 * It is used to test if the given bs is the candidate or recurse more in the
4831 * node graph.
4833 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
4834 BlockDriverState *candidate)
4836 /* return false if basic checks fails */
4837 if (!bs || !bs->drv) {
4838 return false;
4841 /* the code reached a non block filter driver -> check if the bs is
4842 * the same as the candidate. It's the recursion termination condition.
4844 if (!bs->drv->is_filter) {
4845 return bs == candidate;
4847 /* Down this path the driver is a block filter driver */
4849 /* If the block filter recursion method is defined use it to recurse down
4850 * the node graph.
4852 if (bs->drv->bdrv_recurse_is_first_non_filter) {
4853 return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate);
4856 /* the driver is a block filter but don't allow to recurse -> return false
4858 return false;
4861 /* This function checks if the candidate is the first non filter bs down it's
4862 * bs chain. Since we don't have pointers to parents it explore all bs chains
4863 * from the top. Some filters can choose not to pass down the recursion.
4865 bool bdrv_is_first_non_filter(BlockDriverState *candidate)
4867 BlockDriverState *bs;
4868 BdrvNextIterator it;
4870 /* walk down the bs forest recursively */
4871 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
4872 bool perm;
4874 /* try to recurse in this top level bs */
4875 perm = bdrv_recurse_is_first_non_filter(bs, candidate);
4877 /* candidate is the first non filter */
4878 if (perm) {
4879 bdrv_next_cleanup(&it);
4880 return true;
4884 return false;
4887 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
4888 const char *node_name, Error **errp)
4890 BlockDriverState *to_replace_bs = bdrv_find_node(node_name);
4891 AioContext *aio_context;
4893 if (!to_replace_bs) {
4894 error_setg(errp, "Node name '%s' not found", node_name);
4895 return NULL;
4898 aio_context = bdrv_get_aio_context(to_replace_bs);
4899 aio_context_acquire(aio_context);
4901 if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) {
4902 to_replace_bs = NULL;
4903 goto out;
4906 /* We don't want arbitrary node of the BDS chain to be replaced only the top
4907 * most non filter in order to prevent data corruption.
4908 * Another benefit is that this tests exclude backing files which are
4909 * blocked by the backing blockers.
4911 if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) {
4912 error_setg(errp, "Only top most non filter can be replaced");
4913 to_replace_bs = NULL;
4914 goto out;
4917 out:
4918 aio_context_release(aio_context);
4919 return to_replace_bs;
4922 static bool append_open_options(QDict *d, BlockDriverState *bs)
4924 const QDictEntry *entry;
4925 QemuOptDesc *desc;
4926 BdrvChild *child;
4927 bool found_any = false;
4928 const char *p;
4930 for (entry = qdict_first(bs->options); entry;
4931 entry = qdict_next(bs->options, entry))
4933 /* Exclude options for children */
4934 QLIST_FOREACH(child, &bs->children, next) {
4935 if (strstart(qdict_entry_key(entry), child->name, &p)
4936 && (!*p || *p == '.'))
4938 break;
4941 if (child) {
4942 continue;
4945 /* And exclude all non-driver-specific options */
4946 for (desc = bdrv_runtime_opts.desc; desc->name; desc++) {
4947 if (!strcmp(qdict_entry_key(entry), desc->name)) {
4948 break;
4951 if (desc->name) {
4952 continue;
4955 qobject_incref(qdict_entry_value(entry));
4956 qdict_put_obj(d, qdict_entry_key(entry), qdict_entry_value(entry));
4957 found_any = true;
4960 return found_any;
4963 /* Updates the following BDS fields:
4964 * - exact_filename: A filename which may be used for opening a block device
4965 * which (mostly) equals the given BDS (even without any
4966 * other options; so reading and writing must return the same
4967 * results, but caching etc. may be different)
4968 * - full_open_options: Options which, when given when opening a block device
4969 * (without a filename), result in a BDS (mostly)
4970 * equalling the given one
4971 * - filename: If exact_filename is set, it is copied here. Otherwise,
4972 * full_open_options is converted to a JSON object, prefixed with
4973 * "json:" (for use through the JSON pseudo protocol) and put here.
4975 void bdrv_refresh_filename(BlockDriverState *bs)
4977 BlockDriver *drv = bs->drv;
4978 QDict *opts;
4980 if (!drv) {
4981 return;
4984 /* This BDS's file name will most probably depend on its file's name, so
4985 * refresh that first */
4986 if (bs->file) {
4987 bdrv_refresh_filename(bs->file->bs);
4990 if (drv->bdrv_refresh_filename) {
4991 /* Obsolete information is of no use here, so drop the old file name
4992 * information before refreshing it */
4993 bs->exact_filename[0] = '\0';
4994 if (bs->full_open_options) {
4995 QDECREF(bs->full_open_options);
4996 bs->full_open_options = NULL;
4999 opts = qdict_new();
5000 append_open_options(opts, bs);
5001 drv->bdrv_refresh_filename(bs, opts);
5002 QDECREF(opts);
5003 } else if (bs->file) {
5004 /* Try to reconstruct valid information from the underlying file */
5005 bool has_open_options;
5007 bs->exact_filename[0] = '\0';
5008 if (bs->full_open_options) {
5009 QDECREF(bs->full_open_options);
5010 bs->full_open_options = NULL;
5013 opts = qdict_new();
5014 has_open_options = append_open_options(opts, bs);
5016 /* If no specific options have been given for this BDS, the filename of
5017 * the underlying file should suffice for this one as well */
5018 if (bs->file->bs->exact_filename[0] && !has_open_options) {
5019 strcpy(bs->exact_filename, bs->file->bs->exact_filename);
5021 /* Reconstructing the full options QDict is simple for most format block
5022 * drivers, as long as the full options are known for the underlying
5023 * file BDS. The full options QDict of that file BDS should somehow
5024 * contain a representation of the filename, therefore the following
5025 * suffices without querying the (exact_)filename of this BDS. */
5026 if (bs->file->bs->full_open_options) {
5027 qdict_put_str(opts, "driver", drv->format_name);
5028 QINCREF(bs->file->bs->full_open_options);
5029 qdict_put(opts, "file", bs->file->bs->full_open_options);
5031 bs->full_open_options = opts;
5032 } else {
5033 QDECREF(opts);
5035 } else if (!bs->full_open_options && qdict_size(bs->options)) {
5036 /* There is no underlying file BDS (at least referenced by BDS.file),
5037 * so the full options QDict should be equal to the options given
5038 * specifically for this block device when it was opened (plus the
5039 * driver specification).
5040 * Because those options don't change, there is no need to update
5041 * full_open_options when it's already set. */
5043 opts = qdict_new();
5044 append_open_options(opts, bs);
5045 qdict_put_str(opts, "driver", drv->format_name);
5047 if (bs->exact_filename[0]) {
5048 /* This may not work for all block protocol drivers (some may
5049 * require this filename to be parsed), but we have to find some
5050 * default solution here, so just include it. If some block driver
5051 * does not support pure options without any filename at all or
5052 * needs some special format of the options QDict, it needs to
5053 * implement the driver-specific bdrv_refresh_filename() function.
5055 qdict_put_str(opts, "filename", bs->exact_filename);
5058 bs->full_open_options = opts;
5061 if (bs->exact_filename[0]) {
5062 pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename);
5063 } else if (bs->full_open_options) {
5064 QString *json = qobject_to_json(QOBJECT(bs->full_open_options));
5065 snprintf(bs->filename, sizeof(bs->filename), "json:%s",
5066 qstring_get_str(json));
5067 QDECREF(json);
5072 * Hot add/remove a BDS's child. So the user can take a child offline when
5073 * it is broken and take a new child online
5075 void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs,
5076 Error **errp)
5079 if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) {
5080 error_setg(errp, "The node %s does not support adding a child",
5081 bdrv_get_device_or_node_name(parent_bs));
5082 return;
5085 if (!QLIST_EMPTY(&child_bs->parents)) {
5086 error_setg(errp, "The node %s already has a parent",
5087 child_bs->node_name);
5088 return;
5091 parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp);
5094 void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp)
5096 BdrvChild *tmp;
5098 if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) {
5099 error_setg(errp, "The node %s does not support removing a child",
5100 bdrv_get_device_or_node_name(parent_bs));
5101 return;
5104 QLIST_FOREACH(tmp, &parent_bs->children, next) {
5105 if (tmp == child) {
5106 break;
5110 if (!tmp) {
5111 error_setg(errp, "The node %s does not have a child named %s",
5112 bdrv_get_device_or_node_name(parent_bs),
5113 bdrv_get_device_or_node_name(child->bs));
5114 return;
5117 parent_bs->drv->bdrv_del_child(parent_bs, child, errp);
5120 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
5121 uint32_t granularity, Error **errp)
5123 BlockDriver *drv = bs->drv;
5125 if (!drv) {
5126 error_setg_errno(errp, ENOMEDIUM,
5127 "Can't store persistent bitmaps to %s",
5128 bdrv_get_device_or_node_name(bs));
5129 return false;
5132 if (!drv->bdrv_can_store_new_dirty_bitmap) {
5133 error_setg_errno(errp, ENOTSUP,
5134 "Can't store persistent bitmaps to %s",
5135 bdrv_get_device_or_node_name(bs));
5136 return false;
5139 return drv->bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp);