numa: Fix format string for "Invalid node" message
[qemu.git] / block.c
blobfa1d06d84676f0f40c9119af8068f10d47d777f1
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"
45 #include "qapi/util.h"
47 #ifdef CONFIG_BSD
48 #include <sys/ioctl.h>
49 #include <sys/queue.h>
50 #ifndef __DragonFly__
51 #include <sys/disk.h>
52 #endif
53 #endif
55 #ifdef _WIN32
56 #include <windows.h>
57 #endif
59 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
61 static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states =
62 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states);
64 static QTAILQ_HEAD(, BlockDriverState) all_bdrv_states =
65 QTAILQ_HEAD_INITIALIZER(all_bdrv_states);
67 static QLIST_HEAD(, BlockDriver) bdrv_drivers =
68 QLIST_HEAD_INITIALIZER(bdrv_drivers);
70 static BlockDriverState *bdrv_open_inherit(const char *filename,
71 const char *reference,
72 QDict *options, int flags,
73 BlockDriverState *parent,
74 const BdrvChildRole *child_role,
75 Error **errp);
77 /* If non-zero, use only whitelisted block drivers */
78 static int use_bdrv_whitelist;
80 #ifdef _WIN32
81 static int is_windows_drive_prefix(const char *filename)
83 return (((filename[0] >= 'a' && filename[0] <= 'z') ||
84 (filename[0] >= 'A' && filename[0] <= 'Z')) &&
85 filename[1] == ':');
88 int is_windows_drive(const char *filename)
90 if (is_windows_drive_prefix(filename) &&
91 filename[2] == '\0')
92 return 1;
93 if (strstart(filename, "\\\\.\\", NULL) ||
94 strstart(filename, "//./", NULL))
95 return 1;
96 return 0;
98 #endif
100 size_t bdrv_opt_mem_align(BlockDriverState *bs)
102 if (!bs || !bs->drv) {
103 /* page size or 4k (hdd sector size) should be on the safe side */
104 return MAX(4096, getpagesize());
107 return bs->bl.opt_mem_alignment;
110 size_t bdrv_min_mem_align(BlockDriverState *bs)
112 if (!bs || !bs->drv) {
113 /* page size or 4k (hdd sector size) should be on the safe side */
114 return MAX(4096, getpagesize());
117 return bs->bl.min_mem_alignment;
120 /* check if the path starts with "<protocol>:" */
121 int path_has_protocol(const char *path)
123 const char *p;
125 #ifdef _WIN32
126 if (is_windows_drive(path) ||
127 is_windows_drive_prefix(path)) {
128 return 0;
130 p = path + strcspn(path, ":/\\");
131 #else
132 p = path + strcspn(path, ":/");
133 #endif
135 return *p == ':';
138 int path_is_absolute(const char *path)
140 #ifdef _WIN32
141 /* specific case for names like: "\\.\d:" */
142 if (is_windows_drive(path) || is_windows_drive_prefix(path)) {
143 return 1;
145 return (*path == '/' || *path == '\\');
146 #else
147 return (*path == '/');
148 #endif
151 /* if filename is absolute, just copy it to dest. Otherwise, build a
152 path to it by considering it is relative to base_path. URL are
153 supported. */
154 void path_combine(char *dest, int dest_size,
155 const char *base_path,
156 const char *filename)
158 const char *p, *p1;
159 int len;
161 if (dest_size <= 0)
162 return;
163 if (path_is_absolute(filename)) {
164 pstrcpy(dest, dest_size, filename);
165 } else {
166 const char *protocol_stripped = NULL;
168 if (path_has_protocol(base_path)) {
169 protocol_stripped = strchr(base_path, ':');
170 if (protocol_stripped) {
171 protocol_stripped++;
174 p = protocol_stripped ?: base_path;
176 p1 = strrchr(base_path, '/');
177 #ifdef _WIN32
179 const char *p2;
180 p2 = strrchr(base_path, '\\');
181 if (!p1 || p2 > p1)
182 p1 = p2;
184 #endif
185 if (p1)
186 p1++;
187 else
188 p1 = base_path;
189 if (p1 > p)
190 p = p1;
191 len = p - base_path;
192 if (len > dest_size - 1)
193 len = dest_size - 1;
194 memcpy(dest, base_path, len);
195 dest[len] = '\0';
196 pstrcat(dest, dest_size, filename);
201 * Helper function for bdrv_parse_filename() implementations to remove optional
202 * protocol prefixes (especially "file:") from a filename and for putting the
203 * stripped filename into the options QDict if there is such a prefix.
205 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix,
206 QDict *options)
208 if (strstart(filename, prefix, &filename)) {
209 /* Stripping the explicit protocol prefix may result in a protocol
210 * prefix being (wrongly) detected (if the filename contains a colon) */
211 if (path_has_protocol(filename)) {
212 QString *fat_filename;
214 /* This means there is some colon before the first slash; therefore,
215 * this cannot be an absolute path */
216 assert(!path_is_absolute(filename));
218 /* And we can thus fix the protocol detection issue by prefixing it
219 * by "./" */
220 fat_filename = qstring_from_str("./");
221 qstring_append(fat_filename, filename);
223 assert(!path_has_protocol(qstring_get_str(fat_filename)));
225 qdict_put(options, "filename", fat_filename);
226 } else {
227 /* If no protocol prefix was detected, we can use the shortened
228 * filename as-is */
229 qdict_put_str(options, "filename", filename);
235 /* Returns whether the image file is opened as read-only. Note that this can
236 * return false and writing to the image file is still not possible because the
237 * image is inactivated. */
238 bool bdrv_is_read_only(BlockDriverState *bs)
240 return bs->read_only;
243 /* Returns whether the image file can be written to right now */
244 bool bdrv_is_writable(BlockDriverState *bs)
246 return !bdrv_is_read_only(bs) && !(bs->open_flags & BDRV_O_INACTIVE);
249 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
251 /* Do not set read_only if copy_on_read is enabled */
252 if (bs->copy_on_read && read_only) {
253 error_setg(errp, "Can't set node '%s' to r/o with copy-on-read enabled",
254 bdrv_get_device_or_node_name(bs));
255 return -EINVAL;
258 /* Do not clear read_only if it is prohibited */
259 if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR)) {
260 error_setg(errp, "Node '%s' is read only",
261 bdrv_get_device_or_node_name(bs));
262 return -EPERM;
265 return 0;
268 int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
270 int ret = 0;
272 ret = bdrv_can_set_read_only(bs, read_only, errp);
273 if (ret < 0) {
274 return ret;
277 bs->read_only = read_only;
278 return 0;
281 void bdrv_get_full_backing_filename_from_filename(const char *backed,
282 const char *backing,
283 char *dest, size_t sz,
284 Error **errp)
286 if (backing[0] == '\0' || path_has_protocol(backing) ||
287 path_is_absolute(backing))
289 pstrcpy(dest, sz, backing);
290 } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) {
291 error_setg(errp, "Cannot use relative backing file names for '%s'",
292 backed);
293 } else {
294 path_combine(dest, sz, backed, backing);
298 void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz,
299 Error **errp)
301 char *backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename;
303 bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file,
304 dest, sz, errp);
307 void bdrv_register(BlockDriver *bdrv)
309 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list);
312 BlockDriverState *bdrv_new(void)
314 BlockDriverState *bs;
315 int i;
317 bs = g_new0(BlockDriverState, 1);
318 QLIST_INIT(&bs->dirty_bitmaps);
319 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
320 QLIST_INIT(&bs->op_blockers[i]);
322 notifier_with_return_list_init(&bs->before_write_notifiers);
323 bs->refcnt = 1;
324 bs->aio_context = qemu_get_aio_context();
326 qemu_co_queue_init(&bs->flush_queue);
328 QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list);
330 return bs;
333 static BlockDriver *bdrv_do_find_format(const char *format_name)
335 BlockDriver *drv1;
337 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
338 if (!strcmp(drv1->format_name, format_name)) {
339 return drv1;
343 return NULL;
346 BlockDriver *bdrv_find_format(const char *format_name)
348 BlockDriver *drv1;
349 int i;
351 drv1 = bdrv_do_find_format(format_name);
352 if (drv1) {
353 return drv1;
356 /* The driver isn't registered, maybe we need to load a module */
357 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
358 if (!strcmp(block_driver_modules[i].format_name, format_name)) {
359 block_module_load_one(block_driver_modules[i].library_name);
360 break;
364 return bdrv_do_find_format(format_name);
367 static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
369 static const char *whitelist_rw[] = {
370 CONFIG_BDRV_RW_WHITELIST
372 static const char *whitelist_ro[] = {
373 CONFIG_BDRV_RO_WHITELIST
375 const char **p;
377 if (!whitelist_rw[0] && !whitelist_ro[0]) {
378 return 1; /* no whitelist, anything goes */
381 for (p = whitelist_rw; *p; p++) {
382 if (!strcmp(drv->format_name, *p)) {
383 return 1;
386 if (read_only) {
387 for (p = whitelist_ro; *p; p++) {
388 if (!strcmp(drv->format_name, *p)) {
389 return 1;
393 return 0;
396 bool bdrv_uses_whitelist(void)
398 return use_bdrv_whitelist;
401 typedef struct CreateCo {
402 BlockDriver *drv;
403 char *filename;
404 QemuOpts *opts;
405 int ret;
406 Error *err;
407 } CreateCo;
409 static void coroutine_fn bdrv_create_co_entry(void *opaque)
411 Error *local_err = NULL;
412 int ret;
414 CreateCo *cco = opaque;
415 assert(cco->drv);
417 ret = cco->drv->bdrv_create(cco->filename, cco->opts, &local_err);
418 error_propagate(&cco->err, local_err);
419 cco->ret = ret;
422 int bdrv_create(BlockDriver *drv, const char* filename,
423 QemuOpts *opts, Error **errp)
425 int ret;
427 Coroutine *co;
428 CreateCo cco = {
429 .drv = drv,
430 .filename = g_strdup(filename),
431 .opts = opts,
432 .ret = NOT_DONE,
433 .err = NULL,
436 if (!drv->bdrv_create) {
437 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name);
438 ret = -ENOTSUP;
439 goto out;
442 if (qemu_in_coroutine()) {
443 /* Fast-path if already in coroutine context */
444 bdrv_create_co_entry(&cco);
445 } else {
446 co = qemu_coroutine_create(bdrv_create_co_entry, &cco);
447 qemu_coroutine_enter(co);
448 while (cco.ret == NOT_DONE) {
449 aio_poll(qemu_get_aio_context(), true);
453 ret = cco.ret;
454 if (ret < 0) {
455 if (cco.err) {
456 error_propagate(errp, cco.err);
457 } else {
458 error_setg_errno(errp, -ret, "Could not create image");
462 out:
463 g_free(cco.filename);
464 return ret;
467 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
469 BlockDriver *drv;
470 Error *local_err = NULL;
471 int ret;
473 drv = bdrv_find_protocol(filename, true, errp);
474 if (drv == NULL) {
475 return -ENOENT;
478 ret = bdrv_create(drv, filename, opts, &local_err);
479 error_propagate(errp, local_err);
480 return ret;
484 * Try to get @bs's logical and physical block size.
485 * On success, store them in @bsz struct and return 0.
486 * On failure return -errno.
487 * @bs must not be empty.
489 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
491 BlockDriver *drv = bs->drv;
493 if (drv && drv->bdrv_probe_blocksizes) {
494 return drv->bdrv_probe_blocksizes(bs, bsz);
497 return -ENOTSUP;
501 * Try to get @bs's geometry (cyls, heads, sectors).
502 * On success, store them in @geo struct and return 0.
503 * On failure return -errno.
504 * @bs must not be empty.
506 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
508 BlockDriver *drv = bs->drv;
510 if (drv && drv->bdrv_probe_geometry) {
511 return drv->bdrv_probe_geometry(bs, geo);
514 return -ENOTSUP;
518 * Create a uniquely-named empty temporary file.
519 * Return 0 upon success, otherwise a negative errno value.
521 int get_tmp_filename(char *filename, int size)
523 #ifdef _WIN32
524 char temp_dir[MAX_PATH];
525 /* GetTempFileName requires that its output buffer (4th param)
526 have length MAX_PATH or greater. */
527 assert(size >= MAX_PATH);
528 return (GetTempPath(MAX_PATH, temp_dir)
529 && GetTempFileName(temp_dir, "qem", 0, filename)
530 ? 0 : -GetLastError());
531 #else
532 int fd;
533 const char *tmpdir;
534 tmpdir = getenv("TMPDIR");
535 if (!tmpdir) {
536 tmpdir = "/var/tmp";
538 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) {
539 return -EOVERFLOW;
541 fd = mkstemp(filename);
542 if (fd < 0) {
543 return -errno;
545 if (close(fd) != 0) {
546 unlink(filename);
547 return -errno;
549 return 0;
550 #endif
554 * Detect host devices. By convention, /dev/cdrom[N] is always
555 * recognized as a host CDROM.
557 static BlockDriver *find_hdev_driver(const char *filename)
559 int score_max = 0, score;
560 BlockDriver *drv = NULL, *d;
562 QLIST_FOREACH(d, &bdrv_drivers, list) {
563 if (d->bdrv_probe_device) {
564 score = d->bdrv_probe_device(filename);
565 if (score > score_max) {
566 score_max = score;
567 drv = d;
572 return drv;
575 static BlockDriver *bdrv_do_find_protocol(const char *protocol)
577 BlockDriver *drv1;
579 QLIST_FOREACH(drv1, &bdrv_drivers, list) {
580 if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) {
581 return drv1;
585 return NULL;
588 BlockDriver *bdrv_find_protocol(const char *filename,
589 bool allow_protocol_prefix,
590 Error **errp)
592 BlockDriver *drv1;
593 char protocol[128];
594 int len;
595 const char *p;
596 int i;
598 /* TODO Drivers without bdrv_file_open must be specified explicitly */
601 * XXX(hch): we really should not let host device detection
602 * override an explicit protocol specification, but moving this
603 * later breaks access to device names with colons in them.
604 * Thanks to the brain-dead persistent naming schemes on udev-
605 * based Linux systems those actually are quite common.
607 drv1 = find_hdev_driver(filename);
608 if (drv1) {
609 return drv1;
612 if (!path_has_protocol(filename) || !allow_protocol_prefix) {
613 return &bdrv_file;
616 p = strchr(filename, ':');
617 assert(p != NULL);
618 len = p - filename;
619 if (len > sizeof(protocol) - 1)
620 len = sizeof(protocol) - 1;
621 memcpy(protocol, filename, len);
622 protocol[len] = '\0';
624 drv1 = bdrv_do_find_protocol(protocol);
625 if (drv1) {
626 return drv1;
629 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) {
630 if (block_driver_modules[i].protocol_name &&
631 !strcmp(block_driver_modules[i].protocol_name, protocol)) {
632 block_module_load_one(block_driver_modules[i].library_name);
633 break;
637 drv1 = bdrv_do_find_protocol(protocol);
638 if (!drv1) {
639 error_setg(errp, "Unknown protocol '%s'", protocol);
641 return drv1;
645 * Guess image format by probing its contents.
646 * This is not a good idea when your image is raw (CVE-2008-2004), but
647 * we do it anyway for backward compatibility.
649 * @buf contains the image's first @buf_size bytes.
650 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
651 * but can be smaller if the image file is smaller)
652 * @filename is its filename.
654 * For all block drivers, call the bdrv_probe() method to get its
655 * probing score.
656 * Return the first block driver with the highest probing score.
658 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
659 const char *filename)
661 int score_max = 0, score;
662 BlockDriver *drv = NULL, *d;
664 QLIST_FOREACH(d, &bdrv_drivers, list) {
665 if (d->bdrv_probe) {
666 score = d->bdrv_probe(buf, buf_size, filename);
667 if (score > score_max) {
668 score_max = score;
669 drv = d;
674 return drv;
677 static int find_image_format(BlockBackend *file, const char *filename,
678 BlockDriver **pdrv, Error **errp)
680 BlockDriver *drv;
681 uint8_t buf[BLOCK_PROBE_BUF_SIZE];
682 int ret = 0;
684 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
685 if (blk_is_sg(file) || !blk_is_inserted(file) || blk_getlength(file) == 0) {
686 *pdrv = &bdrv_raw;
687 return ret;
690 ret = blk_pread(file, 0, buf, sizeof(buf));
691 if (ret < 0) {
692 error_setg_errno(errp, -ret, "Could not read image for determining its "
693 "format");
694 *pdrv = NULL;
695 return ret;
698 drv = bdrv_probe_all(buf, ret, filename);
699 if (!drv) {
700 error_setg(errp, "Could not determine image format: No compatible "
701 "driver found");
702 ret = -ENOENT;
704 *pdrv = drv;
705 return ret;
709 * Set the current 'total_sectors' value
710 * Return 0 on success, -errno on error.
712 static int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
714 BlockDriver *drv = bs->drv;
716 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
717 if (bdrv_is_sg(bs))
718 return 0;
720 /* query actual device if possible, otherwise just trust the hint */
721 if (drv->bdrv_getlength) {
722 int64_t length = drv->bdrv_getlength(bs);
723 if (length < 0) {
724 return length;
726 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE);
729 bs->total_sectors = hint;
730 return 0;
734 * Combines a QDict of new block driver @options with any missing options taken
735 * from @old_options, so that leaving out an option defaults to its old value.
737 static void bdrv_join_options(BlockDriverState *bs, QDict *options,
738 QDict *old_options)
740 if (bs->drv && bs->drv->bdrv_join_options) {
741 bs->drv->bdrv_join_options(options, old_options);
742 } else {
743 qdict_join(options, old_options, false);
748 * Set open flags for a given discard mode
750 * Return 0 on success, -1 if the discard mode was invalid.
752 int bdrv_parse_discard_flags(const char *mode, int *flags)
754 *flags &= ~BDRV_O_UNMAP;
756 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) {
757 /* do nothing */
758 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) {
759 *flags |= BDRV_O_UNMAP;
760 } else {
761 return -1;
764 return 0;
768 * Set open flags for a given cache mode
770 * Return 0 on success, -1 if the cache mode was invalid.
772 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough)
774 *flags &= ~BDRV_O_CACHE_MASK;
776 if (!strcmp(mode, "off") || !strcmp(mode, "none")) {
777 *writethrough = false;
778 *flags |= BDRV_O_NOCACHE;
779 } else if (!strcmp(mode, "directsync")) {
780 *writethrough = true;
781 *flags |= BDRV_O_NOCACHE;
782 } else if (!strcmp(mode, "writeback")) {
783 *writethrough = false;
784 } else if (!strcmp(mode, "unsafe")) {
785 *writethrough = false;
786 *flags |= BDRV_O_NO_FLUSH;
787 } else if (!strcmp(mode, "writethrough")) {
788 *writethrough = true;
789 } else {
790 return -1;
793 return 0;
796 static char *bdrv_child_get_parent_desc(BdrvChild *c)
798 BlockDriverState *parent = c->opaque;
799 return g_strdup(bdrv_get_device_or_node_name(parent));
802 static void bdrv_child_cb_drained_begin(BdrvChild *child)
804 BlockDriverState *bs = child->opaque;
805 bdrv_drained_begin(bs);
808 static void bdrv_child_cb_drained_end(BdrvChild *child)
810 BlockDriverState *bs = child->opaque;
811 bdrv_drained_end(bs);
814 static int bdrv_child_cb_inactivate(BdrvChild *child)
816 BlockDriverState *bs = child->opaque;
817 assert(bs->open_flags & BDRV_O_INACTIVE);
818 return 0;
822 * Returns the options and flags that a temporary snapshot should get, based on
823 * the originally requested flags (the originally requested image will have
824 * flags like a backing file)
826 static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
827 int parent_flags, QDict *parent_options)
829 *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY;
831 /* For temporary files, unconditional cache=unsafe is fine */
832 qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off");
833 qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
835 /* Copy the read-only option from the parent */
836 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
838 /* aio=native doesn't work for cache.direct=off, so disable it for the
839 * temporary snapshot */
840 *child_flags &= ~BDRV_O_NATIVE_AIO;
844 * Returns the options and flags that bs->file should get if a protocol driver
845 * is expected, based on the given options and flags for the parent BDS
847 static void bdrv_inherited_options(int *child_flags, QDict *child_options,
848 int parent_flags, QDict *parent_options)
850 int flags = parent_flags;
852 /* Enable protocol handling, disable format probing for bs->file */
853 flags |= BDRV_O_PROTOCOL;
855 /* If the cache mode isn't explicitly set, inherit direct and no-flush from
856 * the parent. */
857 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
858 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
859 qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
861 /* Inherit the read-only option from the parent if it's not set */
862 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
864 /* Our block drivers take care to send flushes and respect unmap policy,
865 * so we can default to enable both on lower layers regardless of the
866 * corresponding parent options. */
867 qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap");
869 /* Clear flags that only apply to the top layer */
870 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ |
871 BDRV_O_NO_IO);
873 *child_flags = flags;
876 const BdrvChildRole child_file = {
877 .get_parent_desc = bdrv_child_get_parent_desc,
878 .inherit_options = bdrv_inherited_options,
879 .drained_begin = bdrv_child_cb_drained_begin,
880 .drained_end = bdrv_child_cb_drained_end,
881 .inactivate = bdrv_child_cb_inactivate,
885 * Returns the options and flags that bs->file should get if the use of formats
886 * (and not only protocols) is permitted for it, based on the given options and
887 * flags for the parent BDS
889 static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options,
890 int parent_flags, QDict *parent_options)
892 child_file.inherit_options(child_flags, child_options,
893 parent_flags, parent_options);
895 *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO);
898 const BdrvChildRole child_format = {
899 .get_parent_desc = bdrv_child_get_parent_desc,
900 .inherit_options = bdrv_inherited_fmt_options,
901 .drained_begin = bdrv_child_cb_drained_begin,
902 .drained_end = bdrv_child_cb_drained_end,
903 .inactivate = bdrv_child_cb_inactivate,
906 static void bdrv_backing_attach(BdrvChild *c)
908 BlockDriverState *parent = c->opaque;
909 BlockDriverState *backing_hd = c->bs;
911 assert(!parent->backing_blocker);
912 error_setg(&parent->backing_blocker,
913 "node is used as backing hd of '%s'",
914 bdrv_get_device_or_node_name(parent));
916 parent->open_flags &= ~BDRV_O_NO_BACKING;
917 pstrcpy(parent->backing_file, sizeof(parent->backing_file),
918 backing_hd->filename);
919 pstrcpy(parent->backing_format, sizeof(parent->backing_format),
920 backing_hd->drv ? backing_hd->drv->format_name : "");
922 bdrv_op_block_all(backing_hd, parent->backing_blocker);
923 /* Otherwise we won't be able to commit or stream */
924 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,
925 parent->backing_blocker);
926 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_STREAM,
927 parent->backing_blocker);
929 * We do backup in 3 ways:
930 * 1. drive backup
931 * The target bs is new opened, and the source is top BDS
932 * 2. blockdev backup
933 * Both the source and the target are top BDSes.
934 * 3. internal backup(used for block replication)
935 * Both the source and the target are backing file
937 * In case 1 and 2, neither the source nor the target is the backing file.
938 * In case 3, we will block the top BDS, so there is only one block job
939 * for the top BDS and its backing chain.
941 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_SOURCE,
942 parent->backing_blocker);
943 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_TARGET,
944 parent->backing_blocker);
947 static void bdrv_backing_detach(BdrvChild *c)
949 BlockDriverState *parent = c->opaque;
951 assert(parent->backing_blocker);
952 bdrv_op_unblock_all(c->bs, parent->backing_blocker);
953 error_free(parent->backing_blocker);
954 parent->backing_blocker = NULL;
958 * Returns the options and flags that bs->backing should get, based on the
959 * given options and flags for the parent BDS
961 static void bdrv_backing_options(int *child_flags, QDict *child_options,
962 int parent_flags, QDict *parent_options)
964 int flags = parent_flags;
966 /* The cache mode is inherited unmodified for backing files; except WCE,
967 * which is only applied on the top level (BlockBackend) */
968 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
969 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
970 qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
972 /* backing files always opened read-only */
973 qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on");
974 flags &= ~BDRV_O_COPY_ON_READ;
976 /* snapshot=on is handled on the top layer */
977 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY);
979 *child_flags = flags;
982 const BdrvChildRole child_backing = {
983 .get_parent_desc = bdrv_child_get_parent_desc,
984 .attach = bdrv_backing_attach,
985 .detach = bdrv_backing_detach,
986 .inherit_options = bdrv_backing_options,
987 .drained_begin = bdrv_child_cb_drained_begin,
988 .drained_end = bdrv_child_cb_drained_end,
989 .inactivate = bdrv_child_cb_inactivate,
992 static int bdrv_open_flags(BlockDriverState *bs, int flags)
994 int open_flags = flags;
997 * Clear flags that are internal to the block layer before opening the
998 * image.
1000 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL);
1003 * Snapshots should be writable.
1005 if (flags & BDRV_O_TEMPORARY) {
1006 open_flags |= BDRV_O_RDWR;
1009 return open_flags;
1012 static void update_flags_from_options(int *flags, QemuOpts *opts)
1014 *flags &= ~BDRV_O_CACHE_MASK;
1016 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_NO_FLUSH));
1017 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
1018 *flags |= BDRV_O_NO_FLUSH;
1021 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT));
1022 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_DIRECT, false)) {
1023 *flags |= BDRV_O_NOCACHE;
1026 *flags &= ~BDRV_O_RDWR;
1028 assert(qemu_opt_find(opts, BDRV_OPT_READ_ONLY));
1029 if (!qemu_opt_get_bool(opts, BDRV_OPT_READ_ONLY, false)) {
1030 *flags |= BDRV_O_RDWR;
1035 static void update_options_from_flags(QDict *options, int flags)
1037 if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) {
1038 qdict_put_bool(options, BDRV_OPT_CACHE_DIRECT, flags & BDRV_O_NOCACHE);
1040 if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) {
1041 qdict_put_bool(options, BDRV_OPT_CACHE_NO_FLUSH,
1042 flags & BDRV_O_NO_FLUSH);
1044 if (!qdict_haskey(options, BDRV_OPT_READ_ONLY)) {
1045 qdict_put_bool(options, BDRV_OPT_READ_ONLY, !(flags & BDRV_O_RDWR));
1049 static void bdrv_assign_node_name(BlockDriverState *bs,
1050 const char *node_name,
1051 Error **errp)
1053 char *gen_node_name = NULL;
1055 if (!node_name) {
1056 node_name = gen_node_name = id_generate(ID_BLOCK);
1057 } else if (!id_wellformed(node_name)) {
1059 * Check for empty string or invalid characters, but not if it is
1060 * generated (generated names use characters not available to the user)
1062 error_setg(errp, "Invalid node name");
1063 return;
1066 /* takes care of avoiding namespaces collisions */
1067 if (blk_by_name(node_name)) {
1068 error_setg(errp, "node-name=%s is conflicting with a device id",
1069 node_name);
1070 goto out;
1073 /* takes care of avoiding duplicates node names */
1074 if (bdrv_find_node(node_name)) {
1075 error_setg(errp, "Duplicate node name");
1076 goto out;
1079 /* copy node name into the bs and insert it into the graph list */
1080 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
1081 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
1082 out:
1083 g_free(gen_node_name);
1086 static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv,
1087 const char *node_name, QDict *options,
1088 int open_flags, Error **errp)
1090 Error *local_err = NULL;
1091 int ret;
1093 bdrv_assign_node_name(bs, node_name, &local_err);
1094 if (local_err) {
1095 error_propagate(errp, local_err);
1096 return -EINVAL;
1099 bs->drv = drv;
1100 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
1101 bs->opaque = g_malloc0(drv->instance_size);
1103 if (drv->bdrv_file_open) {
1104 assert(!drv->bdrv_needs_filename || bs->filename[0]);
1105 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err);
1106 } else if (drv->bdrv_open) {
1107 ret = drv->bdrv_open(bs, options, open_flags, &local_err);
1108 } else {
1109 ret = 0;
1112 if (ret < 0) {
1113 if (local_err) {
1114 error_propagate(errp, local_err);
1115 } else if (bs->filename[0]) {
1116 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename);
1117 } else {
1118 error_setg_errno(errp, -ret, "Could not open image");
1120 goto free_and_fail;
1123 ret = refresh_total_sectors(bs, bs->total_sectors);
1124 if (ret < 0) {
1125 error_setg_errno(errp, -ret, "Could not refresh total sector count");
1126 goto free_and_fail;
1129 bdrv_refresh_limits(bs, &local_err);
1130 if (local_err) {
1131 error_propagate(errp, local_err);
1132 ret = -EINVAL;
1133 goto free_and_fail;
1136 assert(bdrv_opt_mem_align(bs) != 0);
1137 assert(bdrv_min_mem_align(bs) != 0);
1138 assert(is_power_of_2(bs->bl.request_alignment));
1140 return 0;
1142 free_and_fail:
1143 /* FIXME Close bs first if already opened*/
1144 g_free(bs->opaque);
1145 bs->opaque = NULL;
1146 bs->drv = NULL;
1147 return ret;
1150 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
1151 int flags, Error **errp)
1153 BlockDriverState *bs;
1154 int ret;
1156 bs = bdrv_new();
1157 bs->open_flags = flags;
1158 bs->explicit_options = qdict_new();
1159 bs->options = qdict_new();
1160 bs->opaque = NULL;
1162 update_options_from_flags(bs->options, flags);
1164 ret = bdrv_open_driver(bs, drv, node_name, bs->options, flags, errp);
1165 if (ret < 0) {
1166 QDECREF(bs->explicit_options);
1167 QDECREF(bs->options);
1168 bdrv_unref(bs);
1169 return NULL;
1172 return bs;
1175 QemuOptsList bdrv_runtime_opts = {
1176 .name = "bdrv_common",
1177 .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head),
1178 .desc = {
1180 .name = "node-name",
1181 .type = QEMU_OPT_STRING,
1182 .help = "Node name of the block device node",
1185 .name = "driver",
1186 .type = QEMU_OPT_STRING,
1187 .help = "Block driver to use for the node",
1190 .name = BDRV_OPT_CACHE_DIRECT,
1191 .type = QEMU_OPT_BOOL,
1192 .help = "Bypass software writeback cache on the host",
1195 .name = BDRV_OPT_CACHE_NO_FLUSH,
1196 .type = QEMU_OPT_BOOL,
1197 .help = "Ignore flush requests",
1200 .name = BDRV_OPT_READ_ONLY,
1201 .type = QEMU_OPT_BOOL,
1202 .help = "Node is opened in read-only mode",
1205 .name = "detect-zeroes",
1206 .type = QEMU_OPT_STRING,
1207 .help = "try to optimize zero writes (off, on, unmap)",
1210 .name = "discard",
1211 .type = QEMU_OPT_STRING,
1212 .help = "discard operation (ignore/off, unmap/on)",
1215 .name = BDRV_OPT_FORCE_SHARE,
1216 .type = QEMU_OPT_BOOL,
1217 .help = "always accept other writers (default: off)",
1219 { /* end of list */ }
1224 * Common part for opening disk images and files
1226 * Removes all processed options from *options.
1228 static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file,
1229 QDict *options, Error **errp)
1231 int ret, open_flags;
1232 const char *filename;
1233 const char *driver_name = NULL;
1234 const char *node_name = NULL;
1235 const char *discard;
1236 const char *detect_zeroes;
1237 QemuOpts *opts;
1238 BlockDriver *drv;
1239 Error *local_err = NULL;
1241 assert(bs->file == NULL);
1242 assert(options != NULL && bs->options != options);
1244 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
1245 qemu_opts_absorb_qdict(opts, options, &local_err);
1246 if (local_err) {
1247 error_propagate(errp, local_err);
1248 ret = -EINVAL;
1249 goto fail_opts;
1252 update_flags_from_options(&bs->open_flags, opts);
1254 driver_name = qemu_opt_get(opts, "driver");
1255 drv = bdrv_find_format(driver_name);
1256 assert(drv != NULL);
1258 bs->force_share = qemu_opt_get_bool(opts, BDRV_OPT_FORCE_SHARE, false);
1260 if (bs->force_share && (bs->open_flags & BDRV_O_RDWR)) {
1261 error_setg(errp,
1262 BDRV_OPT_FORCE_SHARE
1263 "=on can only be used with read-only images");
1264 ret = -EINVAL;
1265 goto fail_opts;
1268 if (file != NULL) {
1269 filename = blk_bs(file)->filename;
1270 } else {
1272 * Caution: while qdict_get_try_str() is fine, getting
1273 * non-string types would require more care. When @options
1274 * come from -blockdev or blockdev_add, its members are typed
1275 * according to the QAPI schema, but when they come from
1276 * -drive, they're all QString.
1278 filename = qdict_get_try_str(options, "filename");
1281 if (drv->bdrv_needs_filename && (!filename || !filename[0])) {
1282 error_setg(errp, "The '%s' block driver requires a file name",
1283 drv->format_name);
1284 ret = -EINVAL;
1285 goto fail_opts;
1288 trace_bdrv_open_common(bs, filename ?: "", bs->open_flags,
1289 drv->format_name);
1291 bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
1293 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
1294 error_setg(errp,
1295 !bs->read_only && bdrv_is_whitelisted(drv, true)
1296 ? "Driver '%s' can only be used for read-only devices"
1297 : "Driver '%s' is not whitelisted",
1298 drv->format_name);
1299 ret = -ENOTSUP;
1300 goto fail_opts;
1303 assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */
1304 if (bs->open_flags & BDRV_O_COPY_ON_READ) {
1305 if (!bs->read_only) {
1306 bdrv_enable_copy_on_read(bs);
1307 } else {
1308 error_setg(errp, "Can't use copy-on-read on read-only device");
1309 ret = -EINVAL;
1310 goto fail_opts;
1314 discard = qemu_opt_get(opts, "discard");
1315 if (discard != NULL) {
1316 if (bdrv_parse_discard_flags(discard, &bs->open_flags) != 0) {
1317 error_setg(errp, "Invalid discard option");
1318 ret = -EINVAL;
1319 goto fail_opts;
1323 detect_zeroes = qemu_opt_get(opts, "detect-zeroes");
1324 if (detect_zeroes) {
1325 BlockdevDetectZeroesOptions value =
1326 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
1327 detect_zeroes,
1328 BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX,
1329 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
1330 &local_err);
1331 if (local_err) {
1332 error_propagate(errp, local_err);
1333 ret = -EINVAL;
1334 goto fail_opts;
1337 if (value == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
1338 !(bs->open_flags & BDRV_O_UNMAP))
1340 error_setg(errp, "setting detect-zeroes to unmap is not allowed "
1341 "without setting discard operation to unmap");
1342 ret = -EINVAL;
1343 goto fail_opts;
1346 bs->detect_zeroes = value;
1349 if (filename != NULL) {
1350 pstrcpy(bs->filename, sizeof(bs->filename), filename);
1351 } else {
1352 bs->filename[0] = '\0';
1354 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename);
1356 /* Open the image, either directly or using a protocol */
1357 open_flags = bdrv_open_flags(bs, bs->open_flags);
1358 node_name = qemu_opt_get(opts, "node-name");
1360 assert(!drv->bdrv_file_open || file == NULL);
1361 ret = bdrv_open_driver(bs, drv, node_name, options, open_flags, errp);
1362 if (ret < 0) {
1363 goto fail_opts;
1366 qemu_opts_del(opts);
1367 return 0;
1369 fail_opts:
1370 qemu_opts_del(opts);
1371 return ret;
1374 static QDict *parse_json_filename(const char *filename, Error **errp)
1376 QObject *options_obj;
1377 QDict *options;
1378 int ret;
1380 ret = strstart(filename, "json:", &filename);
1381 assert(ret);
1383 options_obj = qobject_from_json(filename, errp);
1384 if (!options_obj) {
1385 /* Work around qobject_from_json() lossage TODO fix that */
1386 if (errp && !*errp) {
1387 error_setg(errp, "Could not parse the JSON options");
1388 return NULL;
1390 error_prepend(errp, "Could not parse the JSON options: ");
1391 return NULL;
1394 options = qobject_to_qdict(options_obj);
1395 if (!options) {
1396 qobject_decref(options_obj);
1397 error_setg(errp, "Invalid JSON object given");
1398 return NULL;
1401 qdict_flatten(options);
1403 return options;
1406 static void parse_json_protocol(QDict *options, const char **pfilename,
1407 Error **errp)
1409 QDict *json_options;
1410 Error *local_err = NULL;
1412 /* Parse json: pseudo-protocol */
1413 if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) {
1414 return;
1417 json_options = parse_json_filename(*pfilename, &local_err);
1418 if (local_err) {
1419 error_propagate(errp, local_err);
1420 return;
1423 /* Options given in the filename have lower priority than options
1424 * specified directly */
1425 qdict_join(options, json_options, false);
1426 QDECREF(json_options);
1427 *pfilename = NULL;
1431 * Fills in default options for opening images and converts the legacy
1432 * filename/flags pair to option QDict entries.
1433 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1434 * block driver has been specified explicitly.
1436 static int bdrv_fill_options(QDict **options, const char *filename,
1437 int *flags, Error **errp)
1439 const char *drvname;
1440 bool protocol = *flags & BDRV_O_PROTOCOL;
1441 bool parse_filename = false;
1442 BlockDriver *drv = NULL;
1443 Error *local_err = NULL;
1446 * Caution: while qdict_get_try_str() is fine, getting non-string
1447 * types would require more care. When @options come from
1448 * -blockdev or blockdev_add, its members are typed according to
1449 * the QAPI schema, but when they come from -drive, they're all
1450 * QString.
1452 drvname = qdict_get_try_str(*options, "driver");
1453 if (drvname) {
1454 drv = bdrv_find_format(drvname);
1455 if (!drv) {
1456 error_setg(errp, "Unknown driver '%s'", drvname);
1457 return -ENOENT;
1459 /* If the user has explicitly specified the driver, this choice should
1460 * override the BDRV_O_PROTOCOL flag */
1461 protocol = drv->bdrv_file_open;
1464 if (protocol) {
1465 *flags |= BDRV_O_PROTOCOL;
1466 } else {
1467 *flags &= ~BDRV_O_PROTOCOL;
1470 /* Translate cache options from flags into options */
1471 update_options_from_flags(*options, *flags);
1473 /* Fetch the file name from the options QDict if necessary */
1474 if (protocol && filename) {
1475 if (!qdict_haskey(*options, "filename")) {
1476 qdict_put_str(*options, "filename", filename);
1477 parse_filename = true;
1478 } else {
1479 error_setg(errp, "Can't specify 'file' and 'filename' options at "
1480 "the same time");
1481 return -EINVAL;
1485 /* Find the right block driver */
1486 /* See cautionary note on accessing @options above */
1487 filename = qdict_get_try_str(*options, "filename");
1489 if (!drvname && protocol) {
1490 if (filename) {
1491 drv = bdrv_find_protocol(filename, parse_filename, errp);
1492 if (!drv) {
1493 return -EINVAL;
1496 drvname = drv->format_name;
1497 qdict_put_str(*options, "driver", drvname);
1498 } else {
1499 error_setg(errp, "Must specify either driver or file");
1500 return -EINVAL;
1504 assert(drv || !protocol);
1506 /* Driver-specific filename parsing */
1507 if (drv && drv->bdrv_parse_filename && parse_filename) {
1508 drv->bdrv_parse_filename(filename, *options, &local_err);
1509 if (local_err) {
1510 error_propagate(errp, local_err);
1511 return -EINVAL;
1514 if (!drv->bdrv_needs_filename) {
1515 qdict_del(*options, "filename");
1519 return 0;
1522 static int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
1523 GSList *ignore_children, Error **errp);
1524 static void bdrv_child_abort_perm_update(BdrvChild *c);
1525 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared);
1527 static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs,
1528 BdrvChild *c,
1529 const BdrvChildRole *role,
1530 uint64_t parent_perm, uint64_t parent_shared,
1531 uint64_t *nperm, uint64_t *nshared)
1533 if (bs->drv && bs->drv->bdrv_child_perm) {
1534 bs->drv->bdrv_child_perm(bs, c, role,
1535 parent_perm, parent_shared,
1536 nperm, nshared);
1538 if (child_bs && child_bs->force_share) {
1539 *nshared = BLK_PERM_ALL;
1544 * Check whether permissions on this node can be changed in a way that
1545 * @cumulative_perms and @cumulative_shared_perms are the new cumulative
1546 * permissions of all its parents. This involves checking whether all necessary
1547 * permission changes to child nodes can be performed.
1549 * A call to this function must always be followed by a call to bdrv_set_perm()
1550 * or bdrv_abort_perm_update().
1552 static int bdrv_check_perm(BlockDriverState *bs, uint64_t cumulative_perms,
1553 uint64_t cumulative_shared_perms,
1554 GSList *ignore_children, Error **errp)
1556 BlockDriver *drv = bs->drv;
1557 BdrvChild *c;
1558 int ret;
1560 /* Write permissions never work with read-only images */
1561 if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) &&
1562 !bdrv_is_writable(bs))
1564 error_setg(errp, "Block node is read-only");
1565 return -EPERM;
1568 /* Check this node */
1569 if (!drv) {
1570 return 0;
1573 if (drv->bdrv_check_perm) {
1574 return drv->bdrv_check_perm(bs, cumulative_perms,
1575 cumulative_shared_perms, errp);
1578 /* Drivers that never have children can omit .bdrv_child_perm() */
1579 if (!drv->bdrv_child_perm) {
1580 assert(QLIST_EMPTY(&bs->children));
1581 return 0;
1584 /* Check all children */
1585 QLIST_FOREACH(c, &bs->children, next) {
1586 uint64_t cur_perm, cur_shared;
1587 bdrv_child_perm(bs, c->bs, c, c->role,
1588 cumulative_perms, cumulative_shared_perms,
1589 &cur_perm, &cur_shared);
1590 ret = bdrv_child_check_perm(c, cur_perm, cur_shared, ignore_children,
1591 errp);
1592 if (ret < 0) {
1593 return ret;
1597 return 0;
1601 * Notifies drivers that after a previous bdrv_check_perm() call, the
1602 * permission update is not performed and any preparations made for it (e.g.
1603 * taken file locks) need to be undone.
1605 * This function recursively notifies all child nodes.
1607 static void bdrv_abort_perm_update(BlockDriverState *bs)
1609 BlockDriver *drv = bs->drv;
1610 BdrvChild *c;
1612 if (!drv) {
1613 return;
1616 if (drv->bdrv_abort_perm_update) {
1617 drv->bdrv_abort_perm_update(bs);
1620 QLIST_FOREACH(c, &bs->children, next) {
1621 bdrv_child_abort_perm_update(c);
1625 static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms,
1626 uint64_t cumulative_shared_perms)
1628 BlockDriver *drv = bs->drv;
1629 BdrvChild *c;
1631 if (!drv) {
1632 return;
1635 /* Update this node */
1636 if (drv->bdrv_set_perm) {
1637 drv->bdrv_set_perm(bs, cumulative_perms, cumulative_shared_perms);
1640 /* Drivers that never have children can omit .bdrv_child_perm() */
1641 if (!drv->bdrv_child_perm) {
1642 assert(QLIST_EMPTY(&bs->children));
1643 return;
1646 /* Update all children */
1647 QLIST_FOREACH(c, &bs->children, next) {
1648 uint64_t cur_perm, cur_shared;
1649 bdrv_child_perm(bs, c->bs, c, c->role,
1650 cumulative_perms, cumulative_shared_perms,
1651 &cur_perm, &cur_shared);
1652 bdrv_child_set_perm(c, cur_perm, cur_shared);
1656 static void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm,
1657 uint64_t *shared_perm)
1659 BdrvChild *c;
1660 uint64_t cumulative_perms = 0;
1661 uint64_t cumulative_shared_perms = BLK_PERM_ALL;
1663 QLIST_FOREACH(c, &bs->parents, next_parent) {
1664 cumulative_perms |= c->perm;
1665 cumulative_shared_perms &= c->shared_perm;
1668 *perm = cumulative_perms;
1669 *shared_perm = cumulative_shared_perms;
1672 static char *bdrv_child_user_desc(BdrvChild *c)
1674 if (c->role->get_parent_desc) {
1675 return c->role->get_parent_desc(c);
1678 return g_strdup("another user");
1681 char *bdrv_perm_names(uint64_t perm)
1683 struct perm_name {
1684 uint64_t perm;
1685 const char *name;
1686 } permissions[] = {
1687 { BLK_PERM_CONSISTENT_READ, "consistent read" },
1688 { BLK_PERM_WRITE, "write" },
1689 { BLK_PERM_WRITE_UNCHANGED, "write unchanged" },
1690 { BLK_PERM_RESIZE, "resize" },
1691 { BLK_PERM_GRAPH_MOD, "change children" },
1692 { 0, NULL }
1695 char *result = g_strdup("");
1696 struct perm_name *p;
1698 for (p = permissions; p->name; p++) {
1699 if (perm & p->perm) {
1700 char *old = result;
1701 result = g_strdup_printf("%s%s%s", old, *old ? ", " : "", p->name);
1702 g_free(old);
1706 return result;
1710 * Checks whether a new reference to @bs can be added if the new user requires
1711 * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is
1712 * set, the BdrvChild objects in this list are ignored in the calculations;
1713 * this allows checking permission updates for an existing reference.
1715 * Needs to be followed by a call to either bdrv_set_perm() or
1716 * bdrv_abort_perm_update(). */
1717 static int bdrv_check_update_perm(BlockDriverState *bs, uint64_t new_used_perm,
1718 uint64_t new_shared_perm,
1719 GSList *ignore_children, Error **errp)
1721 BdrvChild *c;
1722 uint64_t cumulative_perms = new_used_perm;
1723 uint64_t cumulative_shared_perms = new_shared_perm;
1725 /* There is no reason why anyone couldn't tolerate write_unchanged */
1726 assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED);
1728 QLIST_FOREACH(c, &bs->parents, next_parent) {
1729 if (g_slist_find(ignore_children, c)) {
1730 continue;
1733 if ((new_used_perm & c->shared_perm) != new_used_perm) {
1734 char *user = bdrv_child_user_desc(c);
1735 char *perm_names = bdrv_perm_names(new_used_perm & ~c->shared_perm);
1736 error_setg(errp, "Conflicts with use by %s as '%s', which does not "
1737 "allow '%s' on %s",
1738 user, c->name, perm_names, bdrv_get_node_name(c->bs));
1739 g_free(user);
1740 g_free(perm_names);
1741 return -EPERM;
1744 if ((c->perm & new_shared_perm) != c->perm) {
1745 char *user = bdrv_child_user_desc(c);
1746 char *perm_names = bdrv_perm_names(c->perm & ~new_shared_perm);
1747 error_setg(errp, "Conflicts with use by %s as '%s', which uses "
1748 "'%s' on %s",
1749 user, c->name, perm_names, bdrv_get_node_name(c->bs));
1750 g_free(user);
1751 g_free(perm_names);
1752 return -EPERM;
1755 cumulative_perms |= c->perm;
1756 cumulative_shared_perms &= c->shared_perm;
1759 return bdrv_check_perm(bs, cumulative_perms, cumulative_shared_perms,
1760 ignore_children, errp);
1763 /* Needs to be followed by a call to either bdrv_child_set_perm() or
1764 * bdrv_child_abort_perm_update(). */
1765 static int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
1766 GSList *ignore_children, Error **errp)
1768 int ret;
1770 ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c);
1771 ret = bdrv_check_update_perm(c->bs, perm, shared, ignore_children, errp);
1772 g_slist_free(ignore_children);
1774 return ret;
1777 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared)
1779 uint64_t cumulative_perms, cumulative_shared_perms;
1781 c->perm = perm;
1782 c->shared_perm = shared;
1784 bdrv_get_cumulative_perm(c->bs, &cumulative_perms,
1785 &cumulative_shared_perms);
1786 bdrv_set_perm(c->bs, cumulative_perms, cumulative_shared_perms);
1789 static void bdrv_child_abort_perm_update(BdrvChild *c)
1791 bdrv_abort_perm_update(c->bs);
1794 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
1795 Error **errp)
1797 int ret;
1799 ret = bdrv_child_check_perm(c, perm, shared, NULL, errp);
1800 if (ret < 0) {
1801 bdrv_child_abort_perm_update(c);
1802 return ret;
1805 bdrv_child_set_perm(c, perm, shared);
1807 return 0;
1810 #define DEFAULT_PERM_PASSTHROUGH (BLK_PERM_CONSISTENT_READ \
1811 | BLK_PERM_WRITE \
1812 | BLK_PERM_WRITE_UNCHANGED \
1813 | BLK_PERM_RESIZE)
1814 #define DEFAULT_PERM_UNCHANGED (BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH)
1816 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
1817 const BdrvChildRole *role,
1818 uint64_t perm, uint64_t shared,
1819 uint64_t *nperm, uint64_t *nshared)
1821 if (c == NULL) {
1822 *nperm = perm & DEFAULT_PERM_PASSTHROUGH;
1823 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
1824 return;
1827 *nperm = (perm & DEFAULT_PERM_PASSTHROUGH) |
1828 (c->perm & DEFAULT_PERM_UNCHANGED);
1829 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) |
1830 (c->shared_perm & DEFAULT_PERM_UNCHANGED);
1833 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
1834 const BdrvChildRole *role,
1835 uint64_t perm, uint64_t shared,
1836 uint64_t *nperm, uint64_t *nshared)
1838 bool backing = (role == &child_backing);
1839 assert(role == &child_backing || role == &child_file);
1841 if (!backing) {
1842 /* Apart from the modifications below, the same permissions are
1843 * forwarded and left alone as for filters */
1844 bdrv_filter_default_perms(bs, c, role, perm, shared, &perm, &shared);
1846 /* Format drivers may touch metadata even if the guest doesn't write */
1847 if (bdrv_is_writable(bs)) {
1848 perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
1851 /* bs->file always needs to be consistent because of the metadata. We
1852 * can never allow other users to resize or write to it. */
1853 perm |= BLK_PERM_CONSISTENT_READ;
1854 shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
1855 } else {
1856 /* We want consistent read from backing files if the parent needs it.
1857 * No other operations are performed on backing files. */
1858 perm &= BLK_PERM_CONSISTENT_READ;
1860 /* If the parent can deal with changing data, we're okay with a
1861 * writable and resizable backing file. */
1862 /* TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? */
1863 if (shared & BLK_PERM_WRITE) {
1864 shared = BLK_PERM_WRITE | BLK_PERM_RESIZE;
1865 } else {
1866 shared = 0;
1869 shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD |
1870 BLK_PERM_WRITE_UNCHANGED;
1873 if (bs->open_flags & BDRV_O_INACTIVE) {
1874 shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
1877 *nperm = perm;
1878 *nshared = shared;
1881 static void bdrv_replace_child_noperm(BdrvChild *child,
1882 BlockDriverState *new_bs)
1884 BlockDriverState *old_bs = child->bs;
1886 if (old_bs && new_bs) {
1887 assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs));
1889 if (old_bs) {
1890 if (old_bs->quiesce_counter && child->role->drained_end) {
1891 child->role->drained_end(child);
1893 if (child->role->detach) {
1894 child->role->detach(child);
1896 QLIST_REMOVE(child, next_parent);
1899 child->bs = new_bs;
1901 if (new_bs) {
1902 QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
1903 if (new_bs->quiesce_counter && child->role->drained_begin) {
1904 child->role->drained_begin(child);
1907 if (child->role->attach) {
1908 child->role->attach(child);
1914 * Updates @child to change its reference to point to @new_bs, including
1915 * checking and applying the necessary permisson updates both to the old node
1916 * and to @new_bs.
1918 * NULL is passed as @new_bs for removing the reference before freeing @child.
1920 * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this
1921 * function uses bdrv_set_perm() to update the permissions according to the new
1922 * reference that @new_bs gets.
1924 static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
1926 BlockDriverState *old_bs = child->bs;
1927 uint64_t perm, shared_perm;
1929 if (old_bs) {
1930 /* Update permissions for old node. This is guaranteed to succeed
1931 * because we're just taking a parent away, so we're loosening
1932 * restrictions. */
1933 bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm);
1934 bdrv_check_perm(old_bs, perm, shared_perm, NULL, &error_abort);
1935 bdrv_set_perm(old_bs, perm, shared_perm);
1938 bdrv_replace_child_noperm(child, new_bs);
1940 if (new_bs) {
1941 bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm);
1942 bdrv_set_perm(new_bs, perm, shared_perm);
1946 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
1947 const char *child_name,
1948 const BdrvChildRole *child_role,
1949 uint64_t perm, uint64_t shared_perm,
1950 void *opaque, Error **errp)
1952 BdrvChild *child;
1953 int ret;
1955 ret = bdrv_check_update_perm(child_bs, perm, shared_perm, NULL, errp);
1956 if (ret < 0) {
1957 bdrv_abort_perm_update(child_bs);
1958 return NULL;
1961 child = g_new(BdrvChild, 1);
1962 *child = (BdrvChild) {
1963 .bs = NULL,
1964 .name = g_strdup(child_name),
1965 .role = child_role,
1966 .perm = perm,
1967 .shared_perm = shared_perm,
1968 .opaque = opaque,
1971 /* This performs the matching bdrv_set_perm() for the above check. */
1972 bdrv_replace_child(child, child_bs);
1974 return child;
1977 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
1978 BlockDriverState *child_bs,
1979 const char *child_name,
1980 const BdrvChildRole *child_role,
1981 Error **errp)
1983 BdrvChild *child;
1984 uint64_t perm, shared_perm;
1986 bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm);
1988 assert(parent_bs->drv);
1989 assert(bdrv_get_aio_context(parent_bs) == bdrv_get_aio_context(child_bs));
1990 bdrv_child_perm(parent_bs, child_bs, NULL, child_role,
1991 perm, shared_perm, &perm, &shared_perm);
1993 child = bdrv_root_attach_child(child_bs, child_name, child_role,
1994 perm, shared_perm, parent_bs, errp);
1995 if (child == NULL) {
1996 return NULL;
1999 QLIST_INSERT_HEAD(&parent_bs->children, child, next);
2000 return child;
2003 static void bdrv_detach_child(BdrvChild *child)
2005 if (child->next.le_prev) {
2006 QLIST_REMOVE(child, next);
2007 child->next.le_prev = NULL;
2010 bdrv_replace_child(child, NULL);
2012 g_free(child->name);
2013 g_free(child);
2016 void bdrv_root_unref_child(BdrvChild *child)
2018 BlockDriverState *child_bs;
2020 child_bs = child->bs;
2021 bdrv_detach_child(child);
2022 bdrv_unref(child_bs);
2025 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child)
2027 if (child == NULL) {
2028 return;
2031 if (child->bs->inherits_from == parent) {
2032 BdrvChild *c;
2034 /* Remove inherits_from only when the last reference between parent and
2035 * child->bs goes away. */
2036 QLIST_FOREACH(c, &parent->children, next) {
2037 if (c != child && c->bs == child->bs) {
2038 break;
2041 if (c == NULL) {
2042 child->bs->inherits_from = NULL;
2046 bdrv_root_unref_child(child);
2050 static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load)
2052 BdrvChild *c;
2053 QLIST_FOREACH(c, &bs->parents, next_parent) {
2054 if (c->role->change_media) {
2055 c->role->change_media(c, load);
2060 static void bdrv_parent_cb_resize(BlockDriverState *bs)
2062 BdrvChild *c;
2063 QLIST_FOREACH(c, &bs->parents, next_parent) {
2064 if (c->role->resize) {
2065 c->role->resize(c);
2071 * Sets the backing file link of a BDS. A new reference is created; callers
2072 * which don't need their own reference any more must call bdrv_unref().
2074 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
2075 Error **errp)
2077 if (backing_hd) {
2078 bdrv_ref(backing_hd);
2081 if (bs->backing) {
2082 bdrv_unref_child(bs, bs->backing);
2085 if (!backing_hd) {
2086 bs->backing = NULL;
2087 goto out;
2090 bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing,
2091 errp);
2092 if (!bs->backing) {
2093 bdrv_unref(backing_hd);
2096 bdrv_refresh_filename(bs);
2098 out:
2099 bdrv_refresh_limits(bs, NULL);
2103 * Opens the backing file for a BlockDriverState if not yet open
2105 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
2106 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2107 * itself, all options starting with "${bdref_key}." are considered part of the
2108 * BlockdevRef.
2110 * TODO Can this be unified with bdrv_open_image()?
2112 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
2113 const char *bdref_key, Error **errp)
2115 char *backing_filename = g_malloc0(PATH_MAX);
2116 char *bdref_key_dot;
2117 const char *reference = NULL;
2118 int ret = 0;
2119 BlockDriverState *backing_hd;
2120 QDict *options;
2121 QDict *tmp_parent_options = NULL;
2122 Error *local_err = NULL;
2124 if (bs->backing != NULL) {
2125 goto free_exit;
2128 /* NULL means an empty set of options */
2129 if (parent_options == NULL) {
2130 tmp_parent_options = qdict_new();
2131 parent_options = tmp_parent_options;
2134 bs->open_flags &= ~BDRV_O_NO_BACKING;
2136 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
2137 qdict_extract_subqdict(parent_options, &options, bdref_key_dot);
2138 g_free(bdref_key_dot);
2141 * Caution: while qdict_get_try_str() is fine, getting non-string
2142 * types would require more care. When @parent_options come from
2143 * -blockdev or blockdev_add, its members are typed according to
2144 * the QAPI schema, but when they come from -drive, they're all
2145 * QString.
2147 reference = qdict_get_try_str(parent_options, bdref_key);
2148 if (reference || qdict_haskey(options, "file.filename")) {
2149 backing_filename[0] = '\0';
2150 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
2151 QDECREF(options);
2152 goto free_exit;
2153 } else {
2154 bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX,
2155 &local_err);
2156 if (local_err) {
2157 ret = -EINVAL;
2158 error_propagate(errp, local_err);
2159 QDECREF(options);
2160 goto free_exit;
2164 if (!bs->drv || !bs->drv->supports_backing) {
2165 ret = -EINVAL;
2166 error_setg(errp, "Driver doesn't support backing files");
2167 QDECREF(options);
2168 goto free_exit;
2171 if (bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) {
2172 qdict_put_str(options, "driver", bs->backing_format);
2175 backing_hd = bdrv_open_inherit(*backing_filename ? backing_filename : NULL,
2176 reference, options, 0, bs, &child_backing,
2177 errp);
2178 if (!backing_hd) {
2179 bs->open_flags |= BDRV_O_NO_BACKING;
2180 error_prepend(errp, "Could not open backing file: ");
2181 ret = -EINVAL;
2182 goto free_exit;
2185 /* Hook up the backing file link; drop our reference, bs owns the
2186 * backing_hd reference now */
2187 bdrv_set_backing_hd(bs, backing_hd, &local_err);
2188 bdrv_unref(backing_hd);
2189 if (local_err) {
2190 error_propagate(errp, local_err);
2191 ret = -EINVAL;
2192 goto free_exit;
2195 qdict_del(parent_options, bdref_key);
2197 free_exit:
2198 g_free(backing_filename);
2199 QDECREF(tmp_parent_options);
2200 return ret;
2203 static BlockDriverState *
2204 bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
2205 BlockDriverState *parent, const BdrvChildRole *child_role,
2206 bool allow_none, Error **errp)
2208 BlockDriverState *bs = NULL;
2209 QDict *image_options;
2210 char *bdref_key_dot;
2211 const char *reference;
2213 assert(child_role != NULL);
2215 bdref_key_dot = g_strdup_printf("%s.", bdref_key);
2216 qdict_extract_subqdict(options, &image_options, bdref_key_dot);
2217 g_free(bdref_key_dot);
2220 * Caution: while qdict_get_try_str() is fine, getting non-string
2221 * types would require more care. When @options come from
2222 * -blockdev or blockdev_add, its members are typed according to
2223 * the QAPI schema, but when they come from -drive, they're all
2224 * QString.
2226 reference = qdict_get_try_str(options, bdref_key);
2227 if (!filename && !reference && !qdict_size(image_options)) {
2228 if (!allow_none) {
2229 error_setg(errp, "A block device must be specified for \"%s\"",
2230 bdref_key);
2232 QDECREF(image_options);
2233 goto done;
2236 bs = bdrv_open_inherit(filename, reference, image_options, 0,
2237 parent, child_role, errp);
2238 if (!bs) {
2239 goto done;
2242 done:
2243 qdict_del(options, bdref_key);
2244 return bs;
2248 * Opens a disk image whose options are given as BlockdevRef in another block
2249 * device's options.
2251 * If allow_none is true, no image will be opened if filename is false and no
2252 * BlockdevRef is given. NULL will be returned, but errp remains unset.
2254 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
2255 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2256 * itself, all options starting with "${bdref_key}." are considered part of the
2257 * BlockdevRef.
2259 * The BlockdevRef will be removed from the options QDict.
2261 BdrvChild *bdrv_open_child(const char *filename,
2262 QDict *options, const char *bdref_key,
2263 BlockDriverState *parent,
2264 const BdrvChildRole *child_role,
2265 bool allow_none, Error **errp)
2267 BdrvChild *c;
2268 BlockDriverState *bs;
2270 bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_role,
2271 allow_none, errp);
2272 if (bs == NULL) {
2273 return NULL;
2276 c = bdrv_attach_child(parent, bs, bdref_key, child_role, errp);
2277 if (!c) {
2278 bdrv_unref(bs);
2279 return NULL;
2282 return c;
2285 static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
2286 int flags,
2287 QDict *snapshot_options,
2288 Error **errp)
2290 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
2291 char *tmp_filename = g_malloc0(PATH_MAX + 1);
2292 int64_t total_size;
2293 QemuOpts *opts = NULL;
2294 BlockDriverState *bs_snapshot = NULL;
2295 Error *local_err = NULL;
2296 int ret;
2298 /* if snapshot, we create a temporary backing file and open it
2299 instead of opening 'filename' directly */
2301 /* Get the required size from the image */
2302 total_size = bdrv_getlength(bs);
2303 if (total_size < 0) {
2304 error_setg_errno(errp, -total_size, "Could not get image size");
2305 goto out;
2308 /* Create the temporary image */
2309 ret = get_tmp_filename(tmp_filename, PATH_MAX + 1);
2310 if (ret < 0) {
2311 error_setg_errno(errp, -ret, "Could not get temporary filename");
2312 goto out;
2315 opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0,
2316 &error_abort);
2317 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort);
2318 ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp);
2319 qemu_opts_del(opts);
2320 if (ret < 0) {
2321 error_prepend(errp, "Could not create temporary overlay '%s': ",
2322 tmp_filename);
2323 goto out;
2326 /* Prepare options QDict for the temporary file */
2327 qdict_put_str(snapshot_options, "file.driver", "file");
2328 qdict_put_str(snapshot_options, "file.filename", tmp_filename);
2329 qdict_put_str(snapshot_options, "driver", "qcow2");
2331 bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp);
2332 snapshot_options = NULL;
2333 if (!bs_snapshot) {
2334 goto out;
2337 /* bdrv_append() consumes a strong reference to bs_snapshot
2338 * (i.e. it will call bdrv_unref() on it) even on error, so in
2339 * order to be able to return one, we have to increase
2340 * bs_snapshot's refcount here */
2341 bdrv_ref(bs_snapshot);
2342 bdrv_append(bs_snapshot, bs, &local_err);
2343 if (local_err) {
2344 error_propagate(errp, local_err);
2345 bs_snapshot = NULL;
2346 goto out;
2349 out:
2350 QDECREF(snapshot_options);
2351 g_free(tmp_filename);
2352 return bs_snapshot;
2356 * Opens a disk image (raw, qcow2, vmdk, ...)
2358 * options is a QDict of options to pass to the block drivers, or NULL for an
2359 * empty set of options. The reference to the QDict belongs to the block layer
2360 * after the call (even on failure), so if the caller intends to reuse the
2361 * dictionary, it needs to use QINCREF() before calling bdrv_open.
2363 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
2364 * If it is not NULL, the referenced BDS will be reused.
2366 * The reference parameter may be used to specify an existing block device which
2367 * should be opened. If specified, neither options nor a filename may be given,
2368 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
2370 static BlockDriverState *bdrv_open_inherit(const char *filename,
2371 const char *reference,
2372 QDict *options, int flags,
2373 BlockDriverState *parent,
2374 const BdrvChildRole *child_role,
2375 Error **errp)
2377 int ret;
2378 BlockBackend *file = NULL;
2379 BlockDriverState *bs;
2380 BlockDriver *drv = NULL;
2381 const char *drvname;
2382 const char *backing;
2383 Error *local_err = NULL;
2384 QDict *snapshot_options = NULL;
2385 int snapshot_flags = 0;
2387 assert(!child_role || !flags);
2388 assert(!child_role == !parent);
2390 if (reference) {
2391 bool options_non_empty = options ? qdict_size(options) : false;
2392 QDECREF(options);
2394 if (filename || options_non_empty) {
2395 error_setg(errp, "Cannot reference an existing block device with "
2396 "additional options or a new filename");
2397 return NULL;
2400 bs = bdrv_lookup_bs(reference, reference, errp);
2401 if (!bs) {
2402 return NULL;
2405 bdrv_ref(bs);
2406 return bs;
2409 bs = bdrv_new();
2411 /* NULL means an empty set of options */
2412 if (options == NULL) {
2413 options = qdict_new();
2416 /* json: syntax counts as explicit options, as if in the QDict */
2417 parse_json_protocol(options, &filename, &local_err);
2418 if (local_err) {
2419 goto fail;
2422 bs->explicit_options = qdict_clone_shallow(options);
2424 if (child_role) {
2425 bs->inherits_from = parent;
2426 child_role->inherit_options(&flags, options,
2427 parent->open_flags, parent->options);
2430 ret = bdrv_fill_options(&options, filename, &flags, &local_err);
2431 if (local_err) {
2432 goto fail;
2436 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
2437 * Caution: getting a boolean member of @options requires care.
2438 * When @options come from -blockdev or blockdev_add, members are
2439 * typed according to the QAPI schema, but when they come from
2440 * -drive, they're all QString.
2442 if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") &&
2443 !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) {
2444 flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR);
2445 } else {
2446 flags &= ~BDRV_O_RDWR;
2449 if (flags & BDRV_O_SNAPSHOT) {
2450 snapshot_options = qdict_new();
2451 bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options,
2452 flags, options);
2453 /* Let bdrv_backing_options() override "read-only" */
2454 qdict_del(options, BDRV_OPT_READ_ONLY);
2455 bdrv_backing_options(&flags, options, flags, options);
2458 bs->open_flags = flags;
2459 bs->options = options;
2460 options = qdict_clone_shallow(options);
2462 /* Find the right image format driver */
2463 /* See cautionary note on accessing @options above */
2464 drvname = qdict_get_try_str(options, "driver");
2465 if (drvname) {
2466 drv = bdrv_find_format(drvname);
2467 if (!drv) {
2468 error_setg(errp, "Unknown driver: '%s'", drvname);
2469 goto fail;
2473 assert(drvname || !(flags & BDRV_O_PROTOCOL));
2475 /* See cautionary note on accessing @options above */
2476 backing = qdict_get_try_str(options, "backing");
2477 if (backing && *backing == '\0') {
2478 flags |= BDRV_O_NO_BACKING;
2479 qdict_del(options, "backing");
2482 /* Open image file without format layer. This BlockBackend is only used for
2483 * probing, the block drivers will do their own bdrv_open_child() for the
2484 * same BDS, which is why we put the node name back into options. */
2485 if ((flags & BDRV_O_PROTOCOL) == 0) {
2486 BlockDriverState *file_bs;
2488 file_bs = bdrv_open_child_bs(filename, options, "file", bs,
2489 &child_file, true, &local_err);
2490 if (local_err) {
2491 goto fail;
2493 if (file_bs != NULL) {
2494 file = blk_new(BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
2495 blk_insert_bs(file, file_bs, &local_err);
2496 bdrv_unref(file_bs);
2497 if (local_err) {
2498 goto fail;
2501 qdict_put_str(options, "file", bdrv_get_node_name(file_bs));
2505 /* Image format probing */
2506 bs->probed = !drv;
2507 if (!drv && file) {
2508 ret = find_image_format(file, filename, &drv, &local_err);
2509 if (ret < 0) {
2510 goto fail;
2513 * This option update would logically belong in bdrv_fill_options(),
2514 * but we first need to open bs->file for the probing to work, while
2515 * opening bs->file already requires the (mostly) final set of options
2516 * so that cache mode etc. can be inherited.
2518 * Adding the driver later is somewhat ugly, but it's not an option
2519 * that would ever be inherited, so it's correct. We just need to make
2520 * sure to update both bs->options (which has the full effective
2521 * options for bs) and options (which has file.* already removed).
2523 qdict_put_str(bs->options, "driver", drv->format_name);
2524 qdict_put_str(options, "driver", drv->format_name);
2525 } else if (!drv) {
2526 error_setg(errp, "Must specify either driver or file");
2527 goto fail;
2530 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
2531 assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open);
2532 /* file must be NULL if a protocol BDS is about to be created
2533 * (the inverse results in an error message from bdrv_open_common()) */
2534 assert(!(flags & BDRV_O_PROTOCOL) || !file);
2536 /* Open the image */
2537 ret = bdrv_open_common(bs, file, options, &local_err);
2538 if (ret < 0) {
2539 goto fail;
2542 if (file) {
2543 blk_unref(file);
2544 file = NULL;
2547 /* If there is a backing file, use it */
2548 if ((flags & BDRV_O_NO_BACKING) == 0) {
2549 ret = bdrv_open_backing_file(bs, options, "backing", &local_err);
2550 if (ret < 0) {
2551 goto close_and_fail;
2555 bdrv_refresh_filename(bs);
2557 /* Check if any unknown options were used */
2558 if (qdict_size(options) != 0) {
2559 const QDictEntry *entry = qdict_first(options);
2560 if (flags & BDRV_O_PROTOCOL) {
2561 error_setg(errp, "Block protocol '%s' doesn't support the option "
2562 "'%s'", drv->format_name, entry->key);
2563 } else {
2564 error_setg(errp,
2565 "Block format '%s' does not support the option '%s'",
2566 drv->format_name, entry->key);
2569 goto close_and_fail;
2572 if (!bdrv_key_required(bs)) {
2573 bdrv_parent_cb_change_media(bs, true);
2574 } else if (!runstate_check(RUN_STATE_PRELAUNCH)
2575 && !runstate_check(RUN_STATE_INMIGRATE)
2576 && !runstate_check(RUN_STATE_PAUSED)) { /* HACK */
2577 error_setg(errp,
2578 "Guest must be stopped for opening of encrypted image");
2579 goto close_and_fail;
2582 QDECREF(options);
2584 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
2585 * temporary snapshot afterwards. */
2586 if (snapshot_flags) {
2587 BlockDriverState *snapshot_bs;
2588 snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags,
2589 snapshot_options, &local_err);
2590 snapshot_options = NULL;
2591 if (local_err) {
2592 goto close_and_fail;
2594 /* We are not going to return bs but the overlay on top of it
2595 * (snapshot_bs); thus, we have to drop the strong reference to bs
2596 * (which we obtained by calling bdrv_new()). bs will not be deleted,
2597 * though, because the overlay still has a reference to it. */
2598 bdrv_unref(bs);
2599 bs = snapshot_bs;
2602 return bs;
2604 fail:
2605 blk_unref(file);
2606 if (bs->file != NULL) {
2607 bdrv_unref_child(bs, bs->file);
2609 QDECREF(snapshot_options);
2610 QDECREF(bs->explicit_options);
2611 QDECREF(bs->options);
2612 QDECREF(options);
2613 bs->options = NULL;
2614 bdrv_unref(bs);
2615 error_propagate(errp, local_err);
2616 return NULL;
2618 close_and_fail:
2619 bdrv_unref(bs);
2620 QDECREF(snapshot_options);
2621 QDECREF(options);
2622 error_propagate(errp, local_err);
2623 return NULL;
2626 BlockDriverState *bdrv_open(const char *filename, const char *reference,
2627 QDict *options, int flags, Error **errp)
2629 return bdrv_open_inherit(filename, reference, options, flags, NULL,
2630 NULL, errp);
2633 typedef struct BlockReopenQueueEntry {
2634 bool prepared;
2635 BDRVReopenState state;
2636 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry;
2637 } BlockReopenQueueEntry;
2640 * Adds a BlockDriverState to a simple queue for an atomic, transactional
2641 * reopen of multiple devices.
2643 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT
2644 * already performed, or alternatively may be NULL a new BlockReopenQueue will
2645 * be created and initialized. This newly created BlockReopenQueue should be
2646 * passed back in for subsequent calls that are intended to be of the same
2647 * atomic 'set'.
2649 * bs is the BlockDriverState to add to the reopen queue.
2651 * options contains the changed options for the associated bs
2652 * (the BlockReopenQueue takes ownership)
2654 * flags contains the open flags for the associated bs
2656 * returns a pointer to bs_queue, which is either the newly allocated
2657 * bs_queue, or the existing bs_queue being used.
2660 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
2661 BlockDriverState *bs,
2662 QDict *options,
2663 int flags,
2664 const BdrvChildRole *role,
2665 QDict *parent_options,
2666 int parent_flags)
2668 assert(bs != NULL);
2670 BlockReopenQueueEntry *bs_entry;
2671 BdrvChild *child;
2672 QDict *old_options, *explicit_options;
2674 if (bs_queue == NULL) {
2675 bs_queue = g_new0(BlockReopenQueue, 1);
2676 QSIMPLEQ_INIT(bs_queue);
2679 if (!options) {
2680 options = qdict_new();
2683 /* Check if this BlockDriverState is already in the queue */
2684 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
2685 if (bs == bs_entry->state.bs) {
2686 break;
2691 * Precedence of options:
2692 * 1. Explicitly passed in options (highest)
2693 * 2. Set in flags (only for top level)
2694 * 3. Retained from explicitly set options of bs
2695 * 4. Inherited from parent node
2696 * 5. Retained from effective options of bs
2699 if (!parent_options) {
2701 * Any setting represented by flags is always updated. If the
2702 * corresponding QDict option is set, it takes precedence. Otherwise
2703 * the flag is translated into a QDict option. The old setting of bs is
2704 * not considered.
2706 update_options_from_flags(options, flags);
2709 /* Old explicitly set values (don't overwrite by inherited value) */
2710 if (bs_entry) {
2711 old_options = qdict_clone_shallow(bs_entry->state.explicit_options);
2712 } else {
2713 old_options = qdict_clone_shallow(bs->explicit_options);
2715 bdrv_join_options(bs, options, old_options);
2716 QDECREF(old_options);
2718 explicit_options = qdict_clone_shallow(options);
2720 /* Inherit from parent node */
2721 if (parent_options) {
2722 assert(!flags);
2723 role->inherit_options(&flags, options, parent_flags, parent_options);
2726 /* Old values are used for options that aren't set yet */
2727 old_options = qdict_clone_shallow(bs->options);
2728 bdrv_join_options(bs, options, old_options);
2729 QDECREF(old_options);
2731 /* bdrv_open() masks this flag out */
2732 flags &= ~BDRV_O_PROTOCOL;
2734 QLIST_FOREACH(child, &bs->children, next) {
2735 QDict *new_child_options;
2736 char *child_key_dot;
2738 /* reopen can only change the options of block devices that were
2739 * implicitly created and inherited options. For other (referenced)
2740 * block devices, a syntax like "backing.foo" results in an error. */
2741 if (child->bs->inherits_from != bs) {
2742 continue;
2745 child_key_dot = g_strdup_printf("%s.", child->name);
2746 qdict_extract_subqdict(options, &new_child_options, child_key_dot);
2747 g_free(child_key_dot);
2749 bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options, 0,
2750 child->role, options, flags);
2753 if (!bs_entry) {
2754 bs_entry = g_new0(BlockReopenQueueEntry, 1);
2755 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry);
2756 } else {
2757 QDECREF(bs_entry->state.options);
2758 QDECREF(bs_entry->state.explicit_options);
2761 bs_entry->state.bs = bs;
2762 bs_entry->state.options = options;
2763 bs_entry->state.explicit_options = explicit_options;
2764 bs_entry->state.flags = flags;
2766 return bs_queue;
2769 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
2770 BlockDriverState *bs,
2771 QDict *options, int flags)
2773 return bdrv_reopen_queue_child(bs_queue, bs, options, flags,
2774 NULL, NULL, 0);
2778 * Reopen multiple BlockDriverStates atomically & transactionally.
2780 * The queue passed in (bs_queue) must have been built up previous
2781 * via bdrv_reopen_queue().
2783 * Reopens all BDS specified in the queue, with the appropriate
2784 * flags. All devices are prepared for reopen, and failure of any
2785 * device will cause all device changes to be abandonded, and intermediate
2786 * data cleaned up.
2788 * If all devices prepare successfully, then the changes are committed
2789 * to all devices.
2792 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp)
2794 int ret = -1;
2795 BlockReopenQueueEntry *bs_entry, *next;
2796 Error *local_err = NULL;
2798 assert(bs_queue != NULL);
2800 aio_context_release(ctx);
2801 bdrv_drain_all_begin();
2802 aio_context_acquire(ctx);
2804 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
2805 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) {
2806 error_propagate(errp, local_err);
2807 goto cleanup;
2809 bs_entry->prepared = true;
2812 /* If we reach this point, we have success and just need to apply the
2813 * changes
2815 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
2816 bdrv_reopen_commit(&bs_entry->state);
2819 ret = 0;
2821 cleanup:
2822 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
2823 if (ret && bs_entry->prepared) {
2824 bdrv_reopen_abort(&bs_entry->state);
2825 } else if (ret) {
2826 QDECREF(bs_entry->state.explicit_options);
2828 QDECREF(bs_entry->state.options);
2829 g_free(bs_entry);
2831 g_free(bs_queue);
2833 bdrv_drain_all_end();
2835 return ret;
2839 /* Reopen a single BlockDriverState with the specified flags. */
2840 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp)
2842 int ret = -1;
2843 Error *local_err = NULL;
2844 BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags);
2846 ret = bdrv_reopen_multiple(bdrv_get_aio_context(bs), queue, &local_err);
2847 if (local_err != NULL) {
2848 error_propagate(errp, local_err);
2850 return ret;
2855 * Prepares a BlockDriverState for reopen. All changes are staged in the
2856 * 'opaque' field of the BDRVReopenState, which is used and allocated by
2857 * the block driver layer .bdrv_reopen_prepare()
2859 * bs is the BlockDriverState to reopen
2860 * flags are the new open flags
2861 * queue is the reopen queue
2863 * Returns 0 on success, non-zero on error. On error errp will be set
2864 * as well.
2866 * On failure, bdrv_reopen_abort() will be called to clean up any data.
2867 * It is the responsibility of the caller to then call the abort() or
2868 * commit() for any other BDS that have been left in a prepare() state
2871 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
2872 Error **errp)
2874 int ret = -1;
2875 Error *local_err = NULL;
2876 BlockDriver *drv;
2877 QemuOpts *opts;
2878 const char *value;
2879 bool read_only;
2881 assert(reopen_state != NULL);
2882 assert(reopen_state->bs->drv != NULL);
2883 drv = reopen_state->bs->drv;
2885 /* Process generic block layer options */
2886 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
2887 qemu_opts_absorb_qdict(opts, reopen_state->options, &local_err);
2888 if (local_err) {
2889 error_propagate(errp, local_err);
2890 ret = -EINVAL;
2891 goto error;
2894 update_flags_from_options(&reopen_state->flags, opts);
2896 /* node-name and driver must be unchanged. Put them back into the QDict, so
2897 * that they are checked at the end of this function. */
2898 value = qemu_opt_get(opts, "node-name");
2899 if (value) {
2900 qdict_put_str(reopen_state->options, "node-name", value);
2903 value = qemu_opt_get(opts, "driver");
2904 if (value) {
2905 qdict_put_str(reopen_state->options, "driver", value);
2908 /* If we are to stay read-only, do not allow permission change
2909 * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is
2910 * not set, or if the BDS still has copy_on_read enabled */
2911 read_only = !(reopen_state->flags & BDRV_O_RDWR);
2912 ret = bdrv_can_set_read_only(reopen_state->bs, read_only, &local_err);
2913 if (local_err) {
2914 error_propagate(errp, local_err);
2915 goto error;
2919 ret = bdrv_flush(reopen_state->bs);
2920 if (ret) {
2921 error_setg_errno(errp, -ret, "Error flushing drive");
2922 goto error;
2925 if (drv->bdrv_reopen_prepare) {
2926 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err);
2927 if (ret) {
2928 if (local_err != NULL) {
2929 error_propagate(errp, local_err);
2930 } else {
2931 error_setg(errp, "failed while preparing to reopen image '%s'",
2932 reopen_state->bs->filename);
2934 goto error;
2936 } else {
2937 /* It is currently mandatory to have a bdrv_reopen_prepare()
2938 * handler for each supported drv. */
2939 error_setg(errp, "Block format '%s' used by node '%s' "
2940 "does not support reopening files", drv->format_name,
2941 bdrv_get_device_or_node_name(reopen_state->bs));
2942 ret = -1;
2943 goto error;
2946 /* Options that are not handled are only okay if they are unchanged
2947 * compared to the old state. It is expected that some options are only
2948 * used for the initial open, but not reopen (e.g. filename) */
2949 if (qdict_size(reopen_state->options)) {
2950 const QDictEntry *entry = qdict_first(reopen_state->options);
2952 do {
2953 QString *new_obj = qobject_to_qstring(entry->value);
2954 const char *new = qstring_get_str(new_obj);
2956 * Caution: while qdict_get_try_str() is fine, getting
2957 * non-string types would require more care. When
2958 * bs->options come from -blockdev or blockdev_add, its
2959 * members are typed according to the QAPI schema, but
2960 * when they come from -drive, they're all QString.
2962 const char *old = qdict_get_try_str(reopen_state->bs->options,
2963 entry->key);
2965 if (!old || strcmp(new, old)) {
2966 error_setg(errp, "Cannot change the option '%s'", entry->key);
2967 ret = -EINVAL;
2968 goto error;
2970 } while ((entry = qdict_next(reopen_state->options, entry)));
2973 ret = 0;
2975 error:
2976 qemu_opts_del(opts);
2977 return ret;
2981 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
2982 * makes them final by swapping the staging BlockDriverState contents into
2983 * the active BlockDriverState contents.
2985 void bdrv_reopen_commit(BDRVReopenState *reopen_state)
2987 BlockDriver *drv;
2989 assert(reopen_state != NULL);
2990 drv = reopen_state->bs->drv;
2991 assert(drv != NULL);
2993 /* If there are any driver level actions to take */
2994 if (drv->bdrv_reopen_commit) {
2995 drv->bdrv_reopen_commit(reopen_state);
2998 /* set BDS specific flags now */
2999 QDECREF(reopen_state->bs->explicit_options);
3001 reopen_state->bs->explicit_options = reopen_state->explicit_options;
3002 reopen_state->bs->open_flags = reopen_state->flags;
3003 reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
3005 bdrv_refresh_limits(reopen_state->bs, NULL);
3009 * Abort the reopen, and delete and free the staged changes in
3010 * reopen_state
3012 void bdrv_reopen_abort(BDRVReopenState *reopen_state)
3014 BlockDriver *drv;
3016 assert(reopen_state != NULL);
3017 drv = reopen_state->bs->drv;
3018 assert(drv != NULL);
3020 if (drv->bdrv_reopen_abort) {
3021 drv->bdrv_reopen_abort(reopen_state);
3024 QDECREF(reopen_state->explicit_options);
3028 static void bdrv_close(BlockDriverState *bs)
3030 BdrvAioNotifier *ban, *ban_next;
3032 assert(!bs->job);
3033 assert(!bs->refcnt);
3035 bdrv_drained_begin(bs); /* complete I/O */
3036 bdrv_flush(bs);
3037 bdrv_drain(bs); /* in case flush left pending I/O */
3039 bdrv_release_named_dirty_bitmaps(bs);
3040 assert(QLIST_EMPTY(&bs->dirty_bitmaps));
3042 if (bs->drv) {
3043 BdrvChild *child, *next;
3045 bs->drv->bdrv_close(bs);
3046 bs->drv = NULL;
3048 bdrv_set_backing_hd(bs, NULL, &error_abort);
3050 if (bs->file != NULL) {
3051 bdrv_unref_child(bs, bs->file);
3052 bs->file = NULL;
3055 QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
3056 /* TODO Remove bdrv_unref() from drivers' close function and use
3057 * bdrv_unref_child() here */
3058 if (child->bs->inherits_from == bs) {
3059 child->bs->inherits_from = NULL;
3061 bdrv_detach_child(child);
3064 g_free(bs->opaque);
3065 bs->opaque = NULL;
3066 bs->copy_on_read = 0;
3067 bs->backing_file[0] = '\0';
3068 bs->backing_format[0] = '\0';
3069 bs->total_sectors = 0;
3070 bs->encrypted = false;
3071 bs->valid_key = false;
3072 bs->sg = false;
3073 QDECREF(bs->options);
3074 QDECREF(bs->explicit_options);
3075 bs->options = NULL;
3076 QDECREF(bs->full_open_options);
3077 bs->full_open_options = NULL;
3080 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
3081 g_free(ban);
3083 QLIST_INIT(&bs->aio_notifiers);
3084 bdrv_drained_end(bs);
3087 void bdrv_close_all(void)
3089 block_job_cancel_sync_all();
3090 nbd_export_close_all();
3092 /* Drop references from requests still in flight, such as canceled block
3093 * jobs whose AIO context has not been polled yet */
3094 bdrv_drain_all();
3096 blk_remove_all_bs();
3097 blockdev_close_all_bdrv_states();
3099 assert(QTAILQ_EMPTY(&all_bdrv_states));
3102 static bool should_update_child(BdrvChild *c, BlockDriverState *to)
3104 BdrvChild *to_c;
3106 if (c->role->stay_at_node) {
3107 return false;
3110 if (c->role == &child_backing) {
3111 /* If @from is a backing file of @to, ignore the child to avoid
3112 * creating a loop. We only want to change the pointer of other
3113 * parents. */
3114 QLIST_FOREACH(to_c, &to->children, next) {
3115 if (to_c == c) {
3116 break;
3119 if (to_c) {
3120 return false;
3124 return true;
3127 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
3128 Error **errp)
3130 BdrvChild *c, *next;
3131 GSList *list = NULL, *p;
3132 uint64_t old_perm, old_shared;
3133 uint64_t perm = 0, shared = BLK_PERM_ALL;
3134 int ret;
3136 assert(!atomic_read(&from->in_flight));
3137 assert(!atomic_read(&to->in_flight));
3139 /* Make sure that @from doesn't go away until we have successfully attached
3140 * all of its parents to @to. */
3141 bdrv_ref(from);
3143 /* Put all parents into @list and calculate their cumulative permissions */
3144 QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
3145 if (!should_update_child(c, to)) {
3146 continue;
3148 list = g_slist_prepend(list, c);
3149 perm |= c->perm;
3150 shared &= c->shared_perm;
3153 /* Check whether the required permissions can be granted on @to, ignoring
3154 * all BdrvChild in @list so that they can't block themselves. */
3155 ret = bdrv_check_update_perm(to, perm, shared, list, errp);
3156 if (ret < 0) {
3157 bdrv_abort_perm_update(to);
3158 goto out;
3161 /* Now actually perform the change. We performed the permission check for
3162 * all elements of @list at once, so set the permissions all at once at the
3163 * very end. */
3164 for (p = list; p != NULL; p = p->next) {
3165 c = p->data;
3167 bdrv_ref(to);
3168 bdrv_replace_child_noperm(c, to);
3169 bdrv_unref(from);
3172 bdrv_get_cumulative_perm(to, &old_perm, &old_shared);
3173 bdrv_set_perm(to, old_perm | perm, old_shared | shared);
3175 out:
3176 g_slist_free(list);
3177 bdrv_unref(from);
3181 * Add new bs contents at the top of an image chain while the chain is
3182 * live, while keeping required fields on the top layer.
3184 * This will modify the BlockDriverState fields, and swap contents
3185 * between bs_new and bs_top. Both bs_new and bs_top are modified.
3187 * bs_new must not be attached to a BlockBackend.
3189 * This function does not create any image files.
3191 * bdrv_append() takes ownership of a bs_new reference and unrefs it because
3192 * that's what the callers commonly need. bs_new will be referenced by the old
3193 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a
3194 * reference of its own, it must call bdrv_ref().
3196 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
3197 Error **errp)
3199 Error *local_err = NULL;
3201 bdrv_set_backing_hd(bs_new, bs_top, &local_err);
3202 if (local_err) {
3203 error_propagate(errp, local_err);
3204 goto out;
3207 bdrv_replace_node(bs_top, bs_new, &local_err);
3208 if (local_err) {
3209 error_propagate(errp, local_err);
3210 bdrv_set_backing_hd(bs_new, NULL, &error_abort);
3211 goto out;
3214 /* bs_new is now referenced by its new parents, we don't need the
3215 * additional reference any more. */
3216 out:
3217 bdrv_unref(bs_new);
3220 static void bdrv_delete(BlockDriverState *bs)
3222 assert(!bs->job);
3223 assert(bdrv_op_blocker_is_empty(bs));
3224 assert(!bs->refcnt);
3226 bdrv_close(bs);
3228 /* remove from list, if necessary */
3229 if (bs->node_name[0] != '\0') {
3230 QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list);
3232 QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list);
3234 g_free(bs);
3238 * Run consistency checks on an image
3240 * Returns 0 if the check could be completed (it doesn't mean that the image is
3241 * free of errors) or -errno when an internal error occurred. The results of the
3242 * check are stored in res.
3244 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix)
3246 if (bs->drv == NULL) {
3247 return -ENOMEDIUM;
3249 if (bs->drv->bdrv_check == NULL) {
3250 return -ENOTSUP;
3253 memset(res, 0, sizeof(*res));
3254 return bs->drv->bdrv_check(bs, res, fix);
3258 * Return values:
3259 * 0 - success
3260 * -EINVAL - backing format specified, but no file
3261 * -ENOSPC - can't update the backing file because no space is left in the
3262 * image file header
3263 * -ENOTSUP - format driver doesn't support changing the backing file
3265 int bdrv_change_backing_file(BlockDriverState *bs,
3266 const char *backing_file, const char *backing_fmt)
3268 BlockDriver *drv = bs->drv;
3269 int ret;
3271 /* Backing file format doesn't make sense without a backing file */
3272 if (backing_fmt && !backing_file) {
3273 return -EINVAL;
3276 if (drv->bdrv_change_backing_file != NULL) {
3277 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
3278 } else {
3279 ret = -ENOTSUP;
3282 if (ret == 0) {
3283 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
3284 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
3286 return ret;
3290 * Finds the image layer in the chain that has 'bs' as its backing file.
3292 * active is the current topmost image.
3294 * Returns NULL if bs is not found in active's image chain,
3295 * or if active == bs.
3297 * Returns the bottommost base image if bs == NULL.
3299 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
3300 BlockDriverState *bs)
3302 while (active && bs != backing_bs(active)) {
3303 active = backing_bs(active);
3306 return active;
3309 /* Given a BDS, searches for the base layer. */
3310 BlockDriverState *bdrv_find_base(BlockDriverState *bs)
3312 return bdrv_find_overlay(bs, NULL);
3316 * Drops images above 'base' up to and including 'top', and sets the image
3317 * above 'top' to have base as its backing file.
3319 * Requires that the overlay to 'top' is opened r/w, so that the backing file
3320 * information in 'bs' can be properly updated.
3322 * E.g., this will convert the following chain:
3323 * bottom <- base <- intermediate <- top <- active
3325 * to
3327 * bottom <- base <- active
3329 * It is allowed for bottom==base, in which case it converts:
3331 * base <- intermediate <- top <- active
3333 * to
3335 * base <- active
3337 * If backing_file_str is non-NULL, it will be used when modifying top's
3338 * overlay image metadata.
3340 * Error conditions:
3341 * if active == top, that is considered an error
3344 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
3345 BlockDriverState *base, const char *backing_file_str)
3347 BlockDriverState *new_top_bs = NULL;
3348 Error *local_err = NULL;
3349 int ret = -EIO;
3351 if (!top->drv || !base->drv) {
3352 goto exit;
3355 new_top_bs = bdrv_find_overlay(active, top);
3357 if (new_top_bs == NULL) {
3358 /* we could not find the image above 'top', this is an error */
3359 goto exit;
3362 /* special case of new_top_bs->backing->bs already pointing to base - nothing
3363 * to do, no intermediate images */
3364 if (backing_bs(new_top_bs) == base) {
3365 ret = 0;
3366 goto exit;
3369 /* Make sure that base is in the backing chain of top */
3370 if (!bdrv_chain_contains(top, base)) {
3371 goto exit;
3374 /* success - we can delete the intermediate states, and link top->base */
3375 backing_file_str = backing_file_str ? backing_file_str : base->filename;
3376 ret = bdrv_change_backing_file(new_top_bs, backing_file_str,
3377 base->drv ? base->drv->format_name : "");
3378 if (ret) {
3379 goto exit;
3382 bdrv_set_backing_hd(new_top_bs, base, &local_err);
3383 if (local_err) {
3384 ret = -EPERM;
3385 error_report_err(local_err);
3386 goto exit;
3389 ret = 0;
3390 exit:
3391 return ret;
3395 * Truncate file to 'offset' bytes (needed only for file protocols)
3397 int bdrv_truncate(BdrvChild *child, int64_t offset, Error **errp)
3399 BlockDriverState *bs = child->bs;
3400 BlockDriver *drv = bs->drv;
3401 int ret;
3403 assert(child->perm & BLK_PERM_RESIZE);
3405 if (!drv) {
3406 error_setg(errp, "No medium inserted");
3407 return -ENOMEDIUM;
3409 if (!drv->bdrv_truncate) {
3410 error_setg(errp, "Image format driver does not support resize");
3411 return -ENOTSUP;
3413 if (bs->read_only) {
3414 error_setg(errp, "Image is read-only");
3415 return -EACCES;
3418 assert(!(bs->open_flags & BDRV_O_INACTIVE));
3420 ret = drv->bdrv_truncate(bs, offset, errp);
3421 if (ret == 0) {
3422 ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
3423 bdrv_dirty_bitmap_truncate(bs);
3424 bdrv_parent_cb_resize(bs);
3425 ++bs->write_gen;
3427 return ret;
3431 * Length of a allocated file in bytes. Sparse files are counted by actual
3432 * allocated space. Return < 0 if error or unknown.
3434 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs)
3436 BlockDriver *drv = bs->drv;
3437 if (!drv) {
3438 return -ENOMEDIUM;
3440 if (drv->bdrv_get_allocated_file_size) {
3441 return drv->bdrv_get_allocated_file_size(bs);
3443 if (bs->file) {
3444 return bdrv_get_allocated_file_size(bs->file->bs);
3446 return -ENOTSUP;
3450 * Return number of sectors on success, -errno on error.
3452 int64_t bdrv_nb_sectors(BlockDriverState *bs)
3454 BlockDriver *drv = bs->drv;
3456 if (!drv)
3457 return -ENOMEDIUM;
3459 if (drv->has_variable_length) {
3460 int ret = refresh_total_sectors(bs, bs->total_sectors);
3461 if (ret < 0) {
3462 return ret;
3465 return bs->total_sectors;
3469 * Return length in bytes on success, -errno on error.
3470 * The length is always a multiple of BDRV_SECTOR_SIZE.
3472 int64_t bdrv_getlength(BlockDriverState *bs)
3474 int64_t ret = bdrv_nb_sectors(bs);
3476 ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret;
3477 return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE;
3480 /* return 0 as number of sectors if no device present or error */
3481 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
3483 int64_t nb_sectors = bdrv_nb_sectors(bs);
3485 *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors;
3488 bool bdrv_is_sg(BlockDriverState *bs)
3490 return bs->sg;
3493 bool bdrv_is_encrypted(BlockDriverState *bs)
3495 if (bs->backing && bs->backing->bs->encrypted) {
3496 return true;
3498 return bs->encrypted;
3501 bool bdrv_key_required(BlockDriverState *bs)
3503 BdrvChild *backing = bs->backing;
3505 if (backing && backing->bs->encrypted && !backing->bs->valid_key) {
3506 return true;
3508 return (bs->encrypted && !bs->valid_key);
3511 int bdrv_set_key(BlockDriverState *bs, const char *key)
3513 int ret;
3514 if (bs->backing && bs->backing->bs->encrypted) {
3515 ret = bdrv_set_key(bs->backing->bs, key);
3516 if (ret < 0)
3517 return ret;
3518 if (!bs->encrypted)
3519 return 0;
3521 if (!bs->encrypted) {
3522 return -EINVAL;
3523 } else if (!bs->drv || !bs->drv->bdrv_set_key) {
3524 return -ENOMEDIUM;
3526 ret = bs->drv->bdrv_set_key(bs, key);
3527 if (ret < 0) {
3528 bs->valid_key = false;
3529 } else if (!bs->valid_key) {
3530 /* call the change callback now, we skipped it on open */
3531 bs->valid_key = true;
3532 bdrv_parent_cb_change_media(bs, true);
3534 return ret;
3538 * Provide an encryption key for @bs.
3539 * If @key is non-null:
3540 * If @bs is not encrypted, fail.
3541 * Else if the key is invalid, fail.
3542 * Else set @bs's key to @key, replacing the existing key, if any.
3543 * If @key is null:
3544 * If @bs is encrypted and still lacks a key, fail.
3545 * Else do nothing.
3546 * On failure, store an error object through @errp if non-null.
3548 void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp)
3550 if (key) {
3551 if (!bdrv_is_encrypted(bs)) {
3552 error_setg(errp, "Node '%s' is not encrypted",
3553 bdrv_get_device_or_node_name(bs));
3554 } else if (bdrv_set_key(bs, key) < 0) {
3555 error_setg(errp, QERR_INVALID_PASSWORD);
3557 } else {
3558 if (bdrv_key_required(bs)) {
3559 error_set(errp, ERROR_CLASS_DEVICE_ENCRYPTED,
3560 "'%s' (%s) is encrypted",
3561 bdrv_get_device_or_node_name(bs),
3562 bdrv_get_encrypted_filename(bs));
3567 const char *bdrv_get_format_name(BlockDriverState *bs)
3569 return bs->drv ? bs->drv->format_name : NULL;
3572 static int qsort_strcmp(const void *a, const void *b)
3574 return strcmp(*(char *const *)a, *(char *const *)b);
3577 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
3578 void *opaque)
3580 BlockDriver *drv;
3581 int count = 0;
3582 int i;
3583 const char **formats = NULL;
3585 QLIST_FOREACH(drv, &bdrv_drivers, list) {
3586 if (drv->format_name) {
3587 bool found = false;
3588 int i = count;
3589 while (formats && i && !found) {
3590 found = !strcmp(formats[--i], drv->format_name);
3593 if (!found) {
3594 formats = g_renew(const char *, formats, count + 1);
3595 formats[count++] = drv->format_name;
3600 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); i++) {
3601 const char *format_name = block_driver_modules[i].format_name;
3603 if (format_name) {
3604 bool found = false;
3605 int j = count;
3607 while (formats && j && !found) {
3608 found = !strcmp(formats[--j], format_name);
3611 if (!found) {
3612 formats = g_renew(const char *, formats, count + 1);
3613 formats[count++] = format_name;
3618 qsort(formats, count, sizeof(formats[0]), qsort_strcmp);
3620 for (i = 0; i < count; i++) {
3621 it(opaque, formats[i]);
3624 g_free(formats);
3627 /* This function is to find a node in the bs graph */
3628 BlockDriverState *bdrv_find_node(const char *node_name)
3630 BlockDriverState *bs;
3632 assert(node_name);
3634 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
3635 if (!strcmp(node_name, bs->node_name)) {
3636 return bs;
3639 return NULL;
3642 /* Put this QMP function here so it can access the static graph_bdrv_states. */
3643 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp)
3645 BlockDeviceInfoList *list, *entry;
3646 BlockDriverState *bs;
3648 list = NULL;
3649 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
3650 BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, errp);
3651 if (!info) {
3652 qapi_free_BlockDeviceInfoList(list);
3653 return NULL;
3655 entry = g_malloc0(sizeof(*entry));
3656 entry->value = info;
3657 entry->next = list;
3658 list = entry;
3661 return list;
3664 BlockDriverState *bdrv_lookup_bs(const char *device,
3665 const char *node_name,
3666 Error **errp)
3668 BlockBackend *blk;
3669 BlockDriverState *bs;
3671 if (device) {
3672 blk = blk_by_name(device);
3674 if (blk) {
3675 bs = blk_bs(blk);
3676 if (!bs) {
3677 error_setg(errp, "Device '%s' has no medium", device);
3680 return bs;
3684 if (node_name) {
3685 bs = bdrv_find_node(node_name);
3687 if (bs) {
3688 return bs;
3692 error_setg(errp, "Cannot find device=%s nor node_name=%s",
3693 device ? device : "",
3694 node_name ? node_name : "");
3695 return NULL;
3698 /* If 'base' is in the same chain as 'top', return true. Otherwise,
3699 * return false. If either argument is NULL, return false. */
3700 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base)
3702 while (top && top != base) {
3703 top = backing_bs(top);
3706 return top != NULL;
3709 BlockDriverState *bdrv_next_node(BlockDriverState *bs)
3711 if (!bs) {
3712 return QTAILQ_FIRST(&graph_bdrv_states);
3714 return QTAILQ_NEXT(bs, node_list);
3717 const char *bdrv_get_node_name(const BlockDriverState *bs)
3719 return bs->node_name;
3722 const char *bdrv_get_parent_name(const BlockDriverState *bs)
3724 BdrvChild *c;
3725 const char *name;
3727 /* If multiple parents have a name, just pick the first one. */
3728 QLIST_FOREACH(c, &bs->parents, next_parent) {
3729 if (c->role->get_name) {
3730 name = c->role->get_name(c);
3731 if (name && *name) {
3732 return name;
3737 return NULL;
3740 /* TODO check what callers really want: bs->node_name or blk_name() */
3741 const char *bdrv_get_device_name(const BlockDriverState *bs)
3743 return bdrv_get_parent_name(bs) ?: "";
3746 /* This can be used to identify nodes that might not have a device
3747 * name associated. Since node and device names live in the same
3748 * namespace, the result is unambiguous. The exception is if both are
3749 * absent, then this returns an empty (non-null) string. */
3750 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs)
3752 return bdrv_get_parent_name(bs) ?: bs->node_name;
3755 int bdrv_get_flags(BlockDriverState *bs)
3757 return bs->open_flags;
3760 int bdrv_has_zero_init_1(BlockDriverState *bs)
3762 return 1;
3765 int bdrv_has_zero_init(BlockDriverState *bs)
3767 assert(bs->drv);
3769 /* If BS is a copy on write image, it is initialized to
3770 the contents of the base image, which may not be zeroes. */
3771 if (bs->backing) {
3772 return 0;
3774 if (bs->drv->bdrv_has_zero_init) {
3775 return bs->drv->bdrv_has_zero_init(bs);
3778 /* safe default */
3779 return 0;
3782 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs)
3784 BlockDriverInfo bdi;
3786 if (bs->backing) {
3787 return false;
3790 if (bdrv_get_info(bs, &bdi) == 0) {
3791 return bdi.unallocated_blocks_are_zero;
3794 return false;
3797 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
3799 BlockDriverInfo bdi;
3801 if (!(bs->open_flags & BDRV_O_UNMAP)) {
3802 return false;
3805 if (bdrv_get_info(bs, &bdi) == 0) {
3806 return bdi.can_write_zeroes_with_unmap;
3809 return false;
3812 const char *bdrv_get_encrypted_filename(BlockDriverState *bs)
3814 if (bs->backing && bs->backing->bs->encrypted)
3815 return bs->backing_file;
3816 else if (bs->encrypted)
3817 return bs->filename;
3818 else
3819 return NULL;
3822 void bdrv_get_backing_filename(BlockDriverState *bs,
3823 char *filename, int filename_size)
3825 pstrcpy(filename, filename_size, bs->backing_file);
3828 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
3830 BlockDriver *drv = bs->drv;
3831 if (!drv)
3832 return -ENOMEDIUM;
3833 if (!drv->bdrv_get_info)
3834 return -ENOTSUP;
3835 memset(bdi, 0, sizeof(*bdi));
3836 return drv->bdrv_get_info(bs, bdi);
3839 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs)
3841 BlockDriver *drv = bs->drv;
3842 if (drv && drv->bdrv_get_specific_info) {
3843 return drv->bdrv_get_specific_info(bs);
3845 return NULL;
3848 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event)
3850 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
3851 return;
3854 bs->drv->bdrv_debug_event(bs, event);
3857 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
3858 const char *tag)
3860 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) {
3861 bs = bs->file ? bs->file->bs : NULL;
3864 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) {
3865 return bs->drv->bdrv_debug_breakpoint(bs, event, tag);
3868 return -ENOTSUP;
3871 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag)
3873 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) {
3874 bs = bs->file ? bs->file->bs : NULL;
3877 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) {
3878 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag);
3881 return -ENOTSUP;
3884 int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
3886 while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) {
3887 bs = bs->file ? bs->file->bs : NULL;
3890 if (bs && bs->drv && bs->drv->bdrv_debug_resume) {
3891 return bs->drv->bdrv_debug_resume(bs, tag);
3894 return -ENOTSUP;
3897 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag)
3899 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) {
3900 bs = bs->file ? bs->file->bs : NULL;
3903 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) {
3904 return bs->drv->bdrv_debug_is_suspended(bs, tag);
3907 return false;
3910 /* backing_file can either be relative, or absolute, or a protocol. If it is
3911 * relative, it must be relative to the chain. So, passing in bs->filename
3912 * from a BDS as backing_file should not be done, as that may be relative to
3913 * the CWD rather than the chain. */
3914 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
3915 const char *backing_file)
3917 char *filename_full = NULL;
3918 char *backing_file_full = NULL;
3919 char *filename_tmp = NULL;
3920 int is_protocol = 0;
3921 BlockDriverState *curr_bs = NULL;
3922 BlockDriverState *retval = NULL;
3923 Error *local_error = NULL;
3925 if (!bs || !bs->drv || !backing_file) {
3926 return NULL;
3929 filename_full = g_malloc(PATH_MAX);
3930 backing_file_full = g_malloc(PATH_MAX);
3931 filename_tmp = g_malloc(PATH_MAX);
3933 is_protocol = path_has_protocol(backing_file);
3935 for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) {
3937 /* If either of the filename paths is actually a protocol, then
3938 * compare unmodified paths; otherwise make paths relative */
3939 if (is_protocol || path_has_protocol(curr_bs->backing_file)) {
3940 if (strcmp(backing_file, curr_bs->backing_file) == 0) {
3941 retval = curr_bs->backing->bs;
3942 break;
3944 /* Also check against the full backing filename for the image */
3945 bdrv_get_full_backing_filename(curr_bs, backing_file_full, PATH_MAX,
3946 &local_error);
3947 if (local_error == NULL) {
3948 if (strcmp(backing_file, backing_file_full) == 0) {
3949 retval = curr_bs->backing->bs;
3950 break;
3952 } else {
3953 error_free(local_error);
3954 local_error = NULL;
3956 } else {
3957 /* If not an absolute filename path, make it relative to the current
3958 * image's filename path */
3959 path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
3960 backing_file);
3962 /* We are going to compare absolute pathnames */
3963 if (!realpath(filename_tmp, filename_full)) {
3964 continue;
3967 /* We need to make sure the backing filename we are comparing against
3968 * is relative to the current image filename (or absolute) */
3969 path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
3970 curr_bs->backing_file);
3972 if (!realpath(filename_tmp, backing_file_full)) {
3973 continue;
3976 if (strcmp(backing_file_full, filename_full) == 0) {
3977 retval = curr_bs->backing->bs;
3978 break;
3983 g_free(filename_full);
3984 g_free(backing_file_full);
3985 g_free(filename_tmp);
3986 return retval;
3989 int bdrv_get_backing_file_depth(BlockDriverState *bs)
3991 if (!bs->drv) {
3992 return 0;
3995 if (!bs->backing) {
3996 return 0;
3999 return 1 + bdrv_get_backing_file_depth(bs->backing->bs);
4002 void bdrv_init(void)
4004 module_call_init(MODULE_INIT_BLOCK);
4007 void bdrv_init_with_whitelist(void)
4009 use_bdrv_whitelist = 1;
4010 bdrv_init();
4013 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
4015 BdrvChild *child, *parent;
4016 uint64_t perm, shared_perm;
4017 Error *local_err = NULL;
4018 int ret;
4020 if (!bs->drv) {
4021 return;
4024 if (!(bs->open_flags & BDRV_O_INACTIVE)) {
4025 return;
4028 QLIST_FOREACH(child, &bs->children, next) {
4029 bdrv_invalidate_cache(child->bs, &local_err);
4030 if (local_err) {
4031 error_propagate(errp, local_err);
4032 return;
4036 bs->open_flags &= ~BDRV_O_INACTIVE;
4037 if (bs->drv->bdrv_invalidate_cache) {
4038 bs->drv->bdrv_invalidate_cache(bs, &local_err);
4039 if (local_err) {
4040 bs->open_flags |= BDRV_O_INACTIVE;
4041 error_propagate(errp, local_err);
4042 return;
4046 ret = refresh_total_sectors(bs, bs->total_sectors);
4047 if (ret < 0) {
4048 bs->open_flags |= BDRV_O_INACTIVE;
4049 error_setg_errno(errp, -ret, "Could not refresh total sector count");
4050 return;
4053 /* Update permissions, they may differ for inactive nodes */
4054 bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
4055 ret = bdrv_check_perm(bs, perm, shared_perm, NULL, &local_err);
4056 if (ret < 0) {
4057 bs->open_flags |= BDRV_O_INACTIVE;
4058 error_propagate(errp, local_err);
4059 return;
4061 bdrv_set_perm(bs, perm, shared_perm);
4063 QLIST_FOREACH(parent, &bs->parents, next_parent) {
4064 if (parent->role->activate) {
4065 parent->role->activate(parent, &local_err);
4066 if (local_err) {
4067 error_propagate(errp, local_err);
4068 return;
4074 void bdrv_invalidate_cache_all(Error **errp)
4076 BlockDriverState *bs;
4077 Error *local_err = NULL;
4078 BdrvNextIterator it;
4080 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
4081 AioContext *aio_context = bdrv_get_aio_context(bs);
4083 aio_context_acquire(aio_context);
4084 bdrv_invalidate_cache(bs, &local_err);
4085 aio_context_release(aio_context);
4086 if (local_err) {
4087 error_propagate(errp, local_err);
4088 return;
4093 static int bdrv_inactivate_recurse(BlockDriverState *bs,
4094 bool setting_flag)
4096 BdrvChild *child, *parent;
4097 int ret;
4099 if (!setting_flag && bs->drv->bdrv_inactivate) {
4100 ret = bs->drv->bdrv_inactivate(bs);
4101 if (ret < 0) {
4102 return ret;
4106 if (setting_flag) {
4107 uint64_t perm, shared_perm;
4109 bs->open_flags |= BDRV_O_INACTIVE;
4111 QLIST_FOREACH(parent, &bs->parents, next_parent) {
4112 if (parent->role->inactivate) {
4113 ret = parent->role->inactivate(parent);
4114 if (ret < 0) {
4115 bs->open_flags &= ~BDRV_O_INACTIVE;
4116 return ret;
4121 /* Update permissions, they may differ for inactive nodes */
4122 bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
4123 bdrv_check_perm(bs, perm, shared_perm, NULL, &error_abort);
4124 bdrv_set_perm(bs, perm, shared_perm);
4127 QLIST_FOREACH(child, &bs->children, next) {
4128 ret = bdrv_inactivate_recurse(child->bs, setting_flag);
4129 if (ret < 0) {
4130 return ret;
4134 return 0;
4137 int bdrv_inactivate_all(void)
4139 BlockDriverState *bs = NULL;
4140 BdrvNextIterator it;
4141 int ret = 0;
4142 int pass;
4144 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
4145 aio_context_acquire(bdrv_get_aio_context(bs));
4148 /* We do two passes of inactivation. The first pass calls to drivers'
4149 * .bdrv_inactivate callbacks recursively so all cache is flushed to disk;
4150 * the second pass sets the BDRV_O_INACTIVE flag so that no further write
4151 * is allowed. */
4152 for (pass = 0; pass < 2; pass++) {
4153 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
4154 ret = bdrv_inactivate_recurse(bs, pass);
4155 if (ret < 0) {
4156 goto out;
4161 out:
4162 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
4163 aio_context_release(bdrv_get_aio_context(bs));
4166 return ret;
4169 /**************************************************************/
4170 /* removable device support */
4173 * Return TRUE if the media is present
4175 bool bdrv_is_inserted(BlockDriverState *bs)
4177 BlockDriver *drv = bs->drv;
4178 BdrvChild *child;
4180 if (!drv) {
4181 return false;
4183 if (drv->bdrv_is_inserted) {
4184 return drv->bdrv_is_inserted(bs);
4186 QLIST_FOREACH(child, &bs->children, next) {
4187 if (!bdrv_is_inserted(child->bs)) {
4188 return false;
4191 return true;
4195 * Return whether the media changed since the last call to this
4196 * function, or -ENOTSUP if we don't know. Most drivers don't know.
4198 int bdrv_media_changed(BlockDriverState *bs)
4200 BlockDriver *drv = bs->drv;
4202 if (drv && drv->bdrv_media_changed) {
4203 return drv->bdrv_media_changed(bs);
4205 return -ENOTSUP;
4209 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
4211 void bdrv_eject(BlockDriverState *bs, bool eject_flag)
4213 BlockDriver *drv = bs->drv;
4215 if (drv && drv->bdrv_eject) {
4216 drv->bdrv_eject(bs, eject_flag);
4221 * Lock or unlock the media (if it is locked, the user won't be able
4222 * to eject it manually).
4224 void bdrv_lock_medium(BlockDriverState *bs, bool locked)
4226 BlockDriver *drv = bs->drv;
4228 trace_bdrv_lock_medium(bs, locked);
4230 if (drv && drv->bdrv_lock_medium) {
4231 drv->bdrv_lock_medium(bs, locked);
4235 /* Get a reference to bs */
4236 void bdrv_ref(BlockDriverState *bs)
4238 bs->refcnt++;
4241 /* Release a previously grabbed reference to bs.
4242 * If after releasing, reference count is zero, the BlockDriverState is
4243 * deleted. */
4244 void bdrv_unref(BlockDriverState *bs)
4246 if (!bs) {
4247 return;
4249 assert(bs->refcnt > 0);
4250 if (--bs->refcnt == 0) {
4251 bdrv_delete(bs);
4255 struct BdrvOpBlocker {
4256 Error *reason;
4257 QLIST_ENTRY(BdrvOpBlocker) list;
4260 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp)
4262 BdrvOpBlocker *blocker;
4263 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
4264 if (!QLIST_EMPTY(&bs->op_blockers[op])) {
4265 blocker = QLIST_FIRST(&bs->op_blockers[op]);
4266 if (errp) {
4267 *errp = error_copy(blocker->reason);
4268 error_prepend(errp, "Node '%s' is busy: ",
4269 bdrv_get_device_or_node_name(bs));
4271 return true;
4273 return false;
4276 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason)
4278 BdrvOpBlocker *blocker;
4279 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
4281 blocker = g_new0(BdrvOpBlocker, 1);
4282 blocker->reason = reason;
4283 QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list);
4286 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason)
4288 BdrvOpBlocker *blocker, *next;
4289 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
4290 QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) {
4291 if (blocker->reason == reason) {
4292 QLIST_REMOVE(blocker, list);
4293 g_free(blocker);
4298 void bdrv_op_block_all(BlockDriverState *bs, Error *reason)
4300 int i;
4301 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
4302 bdrv_op_block(bs, i, reason);
4306 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason)
4308 int i;
4309 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
4310 bdrv_op_unblock(bs, i, reason);
4314 bool bdrv_op_blocker_is_empty(BlockDriverState *bs)
4316 int i;
4318 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
4319 if (!QLIST_EMPTY(&bs->op_blockers[i])) {
4320 return false;
4323 return true;
4326 void bdrv_img_create(const char *filename, const char *fmt,
4327 const char *base_filename, const char *base_fmt,
4328 char *options, uint64_t img_size, int flags, bool quiet,
4329 Error **errp)
4331 QemuOptsList *create_opts = NULL;
4332 QemuOpts *opts = NULL;
4333 const char *backing_fmt, *backing_file;
4334 int64_t size;
4335 BlockDriver *drv, *proto_drv;
4336 Error *local_err = NULL;
4337 int ret = 0;
4339 /* Find driver and parse its options */
4340 drv = bdrv_find_format(fmt);
4341 if (!drv) {
4342 error_setg(errp, "Unknown file format '%s'", fmt);
4343 return;
4346 proto_drv = bdrv_find_protocol(filename, true, errp);
4347 if (!proto_drv) {
4348 return;
4351 if (!drv->create_opts) {
4352 error_setg(errp, "Format driver '%s' does not support image creation",
4353 drv->format_name);
4354 return;
4357 if (!proto_drv->create_opts) {
4358 error_setg(errp, "Protocol driver '%s' does not support image creation",
4359 proto_drv->format_name);
4360 return;
4363 create_opts = qemu_opts_append(create_opts, drv->create_opts);
4364 create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
4366 /* Create parameter list with default values */
4367 opts = qemu_opts_create(create_opts, NULL, 0, &error_abort);
4368 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, img_size, &error_abort);
4370 /* Parse -o options */
4371 if (options) {
4372 qemu_opts_do_parse(opts, options, NULL, &local_err);
4373 if (local_err) {
4374 error_report_err(local_err);
4375 local_err = NULL;
4376 error_setg(errp, "Invalid options for file format '%s'", fmt);
4377 goto out;
4381 if (base_filename) {
4382 qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename, &local_err);
4383 if (local_err) {
4384 error_setg(errp, "Backing file not supported for file format '%s'",
4385 fmt);
4386 goto out;
4390 if (base_fmt) {
4391 qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt, &local_err);
4392 if (local_err) {
4393 error_setg(errp, "Backing file format not supported for file "
4394 "format '%s'", fmt);
4395 goto out;
4399 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
4400 if (backing_file) {
4401 if (!strcmp(filename, backing_file)) {
4402 error_setg(errp, "Error: Trying to create an image with the "
4403 "same filename as the backing file");
4404 goto out;
4408 backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
4410 // The size for the image must always be specified, with one exception:
4411 // If we are using a backing file, we can obtain the size from there
4412 size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
4413 if (size == -1) {
4414 if (backing_file) {
4415 BlockDriverState *bs;
4416 char *full_backing = g_new0(char, PATH_MAX);
4417 int64_t size;
4418 int back_flags;
4419 QDict *backing_options = NULL;
4421 bdrv_get_full_backing_filename_from_filename(filename, backing_file,
4422 full_backing, PATH_MAX,
4423 &local_err);
4424 if (local_err) {
4425 g_free(full_backing);
4426 goto out;
4429 /* backing files always opened read-only */
4430 back_flags = flags;
4431 back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
4433 if (backing_fmt) {
4434 backing_options = qdict_new();
4435 qdict_put_str(backing_options, "driver", backing_fmt);
4438 bs = bdrv_open(full_backing, NULL, backing_options, back_flags,
4439 &local_err);
4440 g_free(full_backing);
4441 if (!bs) {
4442 goto out;
4444 size = bdrv_getlength(bs);
4445 if (size < 0) {
4446 error_setg_errno(errp, -size, "Could not get size of '%s'",
4447 backing_file);
4448 bdrv_unref(bs);
4449 goto out;
4452 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort);
4454 bdrv_unref(bs);
4455 } else {
4456 error_setg(errp, "Image creation needs a size parameter");
4457 goto out;
4461 if (!quiet) {
4462 printf("Formatting '%s', fmt=%s ", filename, fmt);
4463 qemu_opts_print(opts, " ");
4464 puts("");
4467 ret = bdrv_create(drv, filename, opts, &local_err);
4469 if (ret == -EFBIG) {
4470 /* This is generally a better message than whatever the driver would
4471 * deliver (especially because of the cluster_size_hint), since that
4472 * is most probably not much different from "image too large". */
4473 const char *cluster_size_hint = "";
4474 if (qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 0)) {
4475 cluster_size_hint = " (try using a larger cluster size)";
4477 error_setg(errp, "The image size is too large for file format '%s'"
4478 "%s", fmt, cluster_size_hint);
4479 error_free(local_err);
4480 local_err = NULL;
4483 out:
4484 qemu_opts_del(opts);
4485 qemu_opts_free(create_opts);
4486 error_propagate(errp, local_err);
4489 AioContext *bdrv_get_aio_context(BlockDriverState *bs)
4491 return bs->aio_context;
4494 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co)
4496 aio_co_enter(bdrv_get_aio_context(bs), co);
4499 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban)
4501 QLIST_REMOVE(ban, list);
4502 g_free(ban);
4505 void bdrv_detach_aio_context(BlockDriverState *bs)
4507 BdrvAioNotifier *baf, *baf_tmp;
4508 BdrvChild *child;
4510 if (!bs->drv) {
4511 return;
4514 assert(!bs->walking_aio_notifiers);
4515 bs->walking_aio_notifiers = true;
4516 QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) {
4517 if (baf->deleted) {
4518 bdrv_do_remove_aio_context_notifier(baf);
4519 } else {
4520 baf->detach_aio_context(baf->opaque);
4523 /* Never mind iterating again to check for ->deleted. bdrv_close() will
4524 * remove remaining aio notifiers if we aren't called again.
4526 bs->walking_aio_notifiers = false;
4528 if (bs->drv->bdrv_detach_aio_context) {
4529 bs->drv->bdrv_detach_aio_context(bs);
4531 QLIST_FOREACH(child, &bs->children, next) {
4532 bdrv_detach_aio_context(child->bs);
4535 bs->aio_context = NULL;
4538 void bdrv_attach_aio_context(BlockDriverState *bs,
4539 AioContext *new_context)
4541 BdrvAioNotifier *ban, *ban_tmp;
4542 BdrvChild *child;
4544 if (!bs->drv) {
4545 return;
4548 bs->aio_context = new_context;
4550 QLIST_FOREACH(child, &bs->children, next) {
4551 bdrv_attach_aio_context(child->bs, new_context);
4553 if (bs->drv->bdrv_attach_aio_context) {
4554 bs->drv->bdrv_attach_aio_context(bs, new_context);
4557 assert(!bs->walking_aio_notifiers);
4558 bs->walking_aio_notifiers = true;
4559 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_tmp) {
4560 if (ban->deleted) {
4561 bdrv_do_remove_aio_context_notifier(ban);
4562 } else {
4563 ban->attached_aio_context(new_context, ban->opaque);
4566 bs->walking_aio_notifiers = false;
4569 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
4571 AioContext *ctx = bdrv_get_aio_context(bs);
4573 aio_disable_external(ctx);
4574 bdrv_parent_drained_begin(bs);
4575 bdrv_drain(bs); /* ensure there are no in-flight requests */
4577 while (aio_poll(ctx, false)) {
4578 /* wait for all bottom halves to execute */
4581 bdrv_detach_aio_context(bs);
4583 /* This function executes in the old AioContext so acquire the new one in
4584 * case it runs in a different thread.
4586 aio_context_acquire(new_context);
4587 bdrv_attach_aio_context(bs, new_context);
4588 bdrv_parent_drained_end(bs);
4589 aio_enable_external(ctx);
4590 aio_context_release(new_context);
4593 void bdrv_add_aio_context_notifier(BlockDriverState *bs,
4594 void (*attached_aio_context)(AioContext *new_context, void *opaque),
4595 void (*detach_aio_context)(void *opaque), void *opaque)
4597 BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1);
4598 *ban = (BdrvAioNotifier){
4599 .attached_aio_context = attached_aio_context,
4600 .detach_aio_context = detach_aio_context,
4601 .opaque = opaque
4604 QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list);
4607 void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
4608 void (*attached_aio_context)(AioContext *,
4609 void *),
4610 void (*detach_aio_context)(void *),
4611 void *opaque)
4613 BdrvAioNotifier *ban, *ban_next;
4615 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
4616 if (ban->attached_aio_context == attached_aio_context &&
4617 ban->detach_aio_context == detach_aio_context &&
4618 ban->opaque == opaque &&
4619 ban->deleted == false)
4621 if (bs->walking_aio_notifiers) {
4622 ban->deleted = true;
4623 } else {
4624 bdrv_do_remove_aio_context_notifier(ban);
4626 return;
4630 abort();
4633 int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts,
4634 BlockDriverAmendStatusCB *status_cb, void *cb_opaque)
4636 if (!bs->drv->bdrv_amend_options) {
4637 return -ENOTSUP;
4639 return bs->drv->bdrv_amend_options(bs, opts, status_cb, cb_opaque);
4642 /* This function will be called by the bdrv_recurse_is_first_non_filter method
4643 * of block filter and by bdrv_is_first_non_filter.
4644 * It is used to test if the given bs is the candidate or recurse more in the
4645 * node graph.
4647 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
4648 BlockDriverState *candidate)
4650 /* return false if basic checks fails */
4651 if (!bs || !bs->drv) {
4652 return false;
4655 /* the code reached a non block filter driver -> check if the bs is
4656 * the same as the candidate. It's the recursion termination condition.
4658 if (!bs->drv->is_filter) {
4659 return bs == candidate;
4661 /* Down this path the driver is a block filter driver */
4663 /* If the block filter recursion method is defined use it to recurse down
4664 * the node graph.
4666 if (bs->drv->bdrv_recurse_is_first_non_filter) {
4667 return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate);
4670 /* the driver is a block filter but don't allow to recurse -> return false
4672 return false;
4675 /* This function checks if the candidate is the first non filter bs down it's
4676 * bs chain. Since we don't have pointers to parents it explore all bs chains
4677 * from the top. Some filters can choose not to pass down the recursion.
4679 bool bdrv_is_first_non_filter(BlockDriverState *candidate)
4681 BlockDriverState *bs;
4682 BdrvNextIterator it;
4684 /* walk down the bs forest recursively */
4685 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
4686 bool perm;
4688 /* try to recurse in this top level bs */
4689 perm = bdrv_recurse_is_first_non_filter(bs, candidate);
4691 /* candidate is the first non filter */
4692 if (perm) {
4693 return true;
4697 return false;
4700 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
4701 const char *node_name, Error **errp)
4703 BlockDriverState *to_replace_bs = bdrv_find_node(node_name);
4704 AioContext *aio_context;
4706 if (!to_replace_bs) {
4707 error_setg(errp, "Node name '%s' not found", node_name);
4708 return NULL;
4711 aio_context = bdrv_get_aio_context(to_replace_bs);
4712 aio_context_acquire(aio_context);
4714 if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) {
4715 to_replace_bs = NULL;
4716 goto out;
4719 /* We don't want arbitrary node of the BDS chain to be replaced only the top
4720 * most non filter in order to prevent data corruption.
4721 * Another benefit is that this tests exclude backing files which are
4722 * blocked by the backing blockers.
4724 if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) {
4725 error_setg(errp, "Only top most non filter can be replaced");
4726 to_replace_bs = NULL;
4727 goto out;
4730 out:
4731 aio_context_release(aio_context);
4732 return to_replace_bs;
4735 static bool append_open_options(QDict *d, BlockDriverState *bs)
4737 const QDictEntry *entry;
4738 QemuOptDesc *desc;
4739 BdrvChild *child;
4740 bool found_any = false;
4741 const char *p;
4743 for (entry = qdict_first(bs->options); entry;
4744 entry = qdict_next(bs->options, entry))
4746 /* Exclude options for children */
4747 QLIST_FOREACH(child, &bs->children, next) {
4748 if (strstart(qdict_entry_key(entry), child->name, &p)
4749 && (!*p || *p == '.'))
4751 break;
4754 if (child) {
4755 continue;
4758 /* And exclude all non-driver-specific options */
4759 for (desc = bdrv_runtime_opts.desc; desc->name; desc++) {
4760 if (!strcmp(qdict_entry_key(entry), desc->name)) {
4761 break;
4764 if (desc->name) {
4765 continue;
4768 qobject_incref(qdict_entry_value(entry));
4769 qdict_put_obj(d, qdict_entry_key(entry), qdict_entry_value(entry));
4770 found_any = true;
4773 return found_any;
4776 /* Updates the following BDS fields:
4777 * - exact_filename: A filename which may be used for opening a block device
4778 * which (mostly) equals the given BDS (even without any
4779 * other options; so reading and writing must return the same
4780 * results, but caching etc. may be different)
4781 * - full_open_options: Options which, when given when opening a block device
4782 * (without a filename), result in a BDS (mostly)
4783 * equalling the given one
4784 * - filename: If exact_filename is set, it is copied here. Otherwise,
4785 * full_open_options is converted to a JSON object, prefixed with
4786 * "json:" (for use through the JSON pseudo protocol) and put here.
4788 void bdrv_refresh_filename(BlockDriverState *bs)
4790 BlockDriver *drv = bs->drv;
4791 QDict *opts;
4793 if (!drv) {
4794 return;
4797 /* This BDS's file name will most probably depend on its file's name, so
4798 * refresh that first */
4799 if (bs->file) {
4800 bdrv_refresh_filename(bs->file->bs);
4803 if (drv->bdrv_refresh_filename) {
4804 /* Obsolete information is of no use here, so drop the old file name
4805 * information before refreshing it */
4806 bs->exact_filename[0] = '\0';
4807 if (bs->full_open_options) {
4808 QDECREF(bs->full_open_options);
4809 bs->full_open_options = NULL;
4812 opts = qdict_new();
4813 append_open_options(opts, bs);
4814 drv->bdrv_refresh_filename(bs, opts);
4815 QDECREF(opts);
4816 } else if (bs->file) {
4817 /* Try to reconstruct valid information from the underlying file */
4818 bool has_open_options;
4820 bs->exact_filename[0] = '\0';
4821 if (bs->full_open_options) {
4822 QDECREF(bs->full_open_options);
4823 bs->full_open_options = NULL;
4826 opts = qdict_new();
4827 has_open_options = append_open_options(opts, bs);
4829 /* If no specific options have been given for this BDS, the filename of
4830 * the underlying file should suffice for this one as well */
4831 if (bs->file->bs->exact_filename[0] && !has_open_options) {
4832 strcpy(bs->exact_filename, bs->file->bs->exact_filename);
4834 /* Reconstructing the full options QDict is simple for most format block
4835 * drivers, as long as the full options are known for the underlying
4836 * file BDS. The full options QDict of that file BDS should somehow
4837 * contain a representation of the filename, therefore the following
4838 * suffices without querying the (exact_)filename of this BDS. */
4839 if (bs->file->bs->full_open_options) {
4840 qdict_put_str(opts, "driver", drv->format_name);
4841 QINCREF(bs->file->bs->full_open_options);
4842 qdict_put(opts, "file", bs->file->bs->full_open_options);
4844 bs->full_open_options = opts;
4845 } else {
4846 QDECREF(opts);
4848 } else if (!bs->full_open_options && qdict_size(bs->options)) {
4849 /* There is no underlying file BDS (at least referenced by BDS.file),
4850 * so the full options QDict should be equal to the options given
4851 * specifically for this block device when it was opened (plus the
4852 * driver specification).
4853 * Because those options don't change, there is no need to update
4854 * full_open_options when it's already set. */
4856 opts = qdict_new();
4857 append_open_options(opts, bs);
4858 qdict_put_str(opts, "driver", drv->format_name);
4860 if (bs->exact_filename[0]) {
4861 /* This may not work for all block protocol drivers (some may
4862 * require this filename to be parsed), but we have to find some
4863 * default solution here, so just include it. If some block driver
4864 * does not support pure options without any filename at all or
4865 * needs some special format of the options QDict, it needs to
4866 * implement the driver-specific bdrv_refresh_filename() function.
4868 qdict_put_str(opts, "filename", bs->exact_filename);
4871 bs->full_open_options = opts;
4874 if (bs->exact_filename[0]) {
4875 pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename);
4876 } else if (bs->full_open_options) {
4877 QString *json = qobject_to_json(QOBJECT(bs->full_open_options));
4878 snprintf(bs->filename, sizeof(bs->filename), "json:%s",
4879 qstring_get_str(json));
4880 QDECREF(json);
4885 * Hot add/remove a BDS's child. So the user can take a child offline when
4886 * it is broken and take a new child online
4888 void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs,
4889 Error **errp)
4892 if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) {
4893 error_setg(errp, "The node %s does not support adding a child",
4894 bdrv_get_device_or_node_name(parent_bs));
4895 return;
4898 if (!QLIST_EMPTY(&child_bs->parents)) {
4899 error_setg(errp, "The node %s already has a parent",
4900 child_bs->node_name);
4901 return;
4904 parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp);
4907 void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp)
4909 BdrvChild *tmp;
4911 if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) {
4912 error_setg(errp, "The node %s does not support removing a child",
4913 bdrv_get_device_or_node_name(parent_bs));
4914 return;
4917 QLIST_FOREACH(tmp, &parent_bs->children, next) {
4918 if (tmp == child) {
4919 break;
4923 if (!tmp) {
4924 error_setg(errp, "The node %s does not have a child named %s",
4925 bdrv_get_device_or_node_name(parent_bs),
4926 bdrv_get_device_or_node_name(child->bs));
4927 return;
4930 parent_bs->drv->bdrv_del_child(parent_bs, child, errp);