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
25 #include "qemu/osdep.h"
26 #include "block/trace.h"
27 #include "block/block_int.h"
28 #include "block/blockjob.h"
29 #include "block/nbd.h"
30 #include "block/qdict.h"
31 #include "qemu/error-report.h"
32 #include "module_block.h"
33 #include "qemu/main-loop.h"
34 #include "qemu/module.h"
35 #include "qapi/error.h"
36 #include "qapi/qmp/qdict.h"
37 #include "qapi/qmp/qjson.h"
38 #include "qapi/qmp/qnull.h"
39 #include "qapi/qmp/qstring.h"
40 #include "qapi/qobject-output-visitor.h"
41 #include "qapi/qapi-visit-block-core.h"
42 #include "sysemu/block-backend.h"
43 #include "sysemu/sysemu.h"
44 #include "qemu/notify.h"
45 #include "qemu/option.h"
46 #include "qemu/coroutine.h"
47 #include "block/qapi.h"
48 #include "qemu/timer.h"
49 #include "qemu/cutils.h"
53 #include <sys/ioctl.h>
54 #include <sys/queue.h>
64 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
66 static QTAILQ_HEAD(, BlockDriverState
) graph_bdrv_states
=
67 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states
);
69 static QTAILQ_HEAD(, BlockDriverState
) all_bdrv_states
=
70 QTAILQ_HEAD_INITIALIZER(all_bdrv_states
);
72 static QLIST_HEAD(, BlockDriver
) bdrv_drivers
=
73 QLIST_HEAD_INITIALIZER(bdrv_drivers
);
75 static BlockDriverState
*bdrv_open_inherit(const char *filename
,
76 const char *reference
,
77 QDict
*options
, int flags
,
78 BlockDriverState
*parent
,
79 const BdrvChildRole
*child_role
,
82 /* If non-zero, use only whitelisted block drivers */
83 static int use_bdrv_whitelist
;
86 static int is_windows_drive_prefix(const char *filename
)
88 return (((filename
[0] >= 'a' && filename
[0] <= 'z') ||
89 (filename
[0] >= 'A' && filename
[0] <= 'Z')) &&
93 int is_windows_drive(const char *filename
)
95 if (is_windows_drive_prefix(filename
) &&
98 if (strstart(filename
, "\\\\.\\", NULL
) ||
99 strstart(filename
, "//./", NULL
))
105 size_t bdrv_opt_mem_align(BlockDriverState
*bs
)
107 if (!bs
|| !bs
->drv
) {
108 /* page size or 4k (hdd sector size) should be on the safe side */
109 return MAX(4096, qemu_real_host_page_size
);
112 return bs
->bl
.opt_mem_alignment
;
115 size_t bdrv_min_mem_align(BlockDriverState
*bs
)
117 if (!bs
|| !bs
->drv
) {
118 /* page size or 4k (hdd sector size) should be on the safe side */
119 return MAX(4096, qemu_real_host_page_size
);
122 return bs
->bl
.min_mem_alignment
;
125 /* check if the path starts with "<protocol>:" */
126 int path_has_protocol(const char *path
)
131 if (is_windows_drive(path
) ||
132 is_windows_drive_prefix(path
)) {
135 p
= path
+ strcspn(path
, ":/\\");
137 p
= path
+ strcspn(path
, ":/");
143 int path_is_absolute(const char *path
)
146 /* specific case for names like: "\\.\d:" */
147 if (is_windows_drive(path
) || is_windows_drive_prefix(path
)) {
150 return (*path
== '/' || *path
== '\\');
152 return (*path
== '/');
156 /* if filename is absolute, just return its duplicate. Otherwise, build a
157 path to it by considering it is relative to base_path. URL are
159 char *path_combine(const char *base_path
, const char *filename
)
161 const char *protocol_stripped
= NULL
;
166 if (path_is_absolute(filename
)) {
167 return g_strdup(filename
);
170 if (path_has_protocol(base_path
)) {
171 protocol_stripped
= strchr(base_path
, ':');
172 if (protocol_stripped
) {
176 p
= protocol_stripped ?
: base_path
;
178 p1
= strrchr(base_path
, '/');
182 p2
= strrchr(base_path
, '\\');
183 if (!p1
|| p2
> p1
) {
198 result
= g_malloc(len
+ strlen(filename
) + 1);
199 memcpy(result
, base_path
, len
);
200 strcpy(result
+ len
, filename
);
206 * Helper function for bdrv_parse_filename() implementations to remove optional
207 * protocol prefixes (especially "file:") from a filename and for putting the
208 * stripped filename into the options QDict if there is such a prefix.
210 void bdrv_parse_filename_strip_prefix(const char *filename
, const char *prefix
,
213 if (strstart(filename
, prefix
, &filename
)) {
214 /* Stripping the explicit protocol prefix may result in a protocol
215 * prefix being (wrongly) detected (if the filename contains a colon) */
216 if (path_has_protocol(filename
)) {
217 QString
*fat_filename
;
219 /* This means there is some colon before the first slash; therefore,
220 * this cannot be an absolute path */
221 assert(!path_is_absolute(filename
));
223 /* And we can thus fix the protocol detection issue by prefixing it
225 fat_filename
= qstring_from_str("./");
226 qstring_append(fat_filename
, filename
);
228 assert(!path_has_protocol(qstring_get_str(fat_filename
)));
230 qdict_put(options
, "filename", fat_filename
);
232 /* If no protocol prefix was detected, we can use the shortened
234 qdict_put_str(options
, "filename", filename
);
240 /* Returns whether the image file is opened as read-only. Note that this can
241 * return false and writing to the image file is still not possible because the
242 * image is inactivated. */
243 bool bdrv_is_read_only(BlockDriverState
*bs
)
245 return bs
->read_only
;
248 int bdrv_can_set_read_only(BlockDriverState
*bs
, bool read_only
,
249 bool ignore_allow_rdw
, 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
));
258 /* Do not clear read_only if it is prohibited */
259 if (!read_only
&& !(bs
->open_flags
& BDRV_O_ALLOW_RDWR
) &&
262 error_setg(errp
, "Node '%s' is read only",
263 bdrv_get_device_or_node_name(bs
));
271 * Called by a driver that can only provide a read-only image.
273 * Returns 0 if the node is already read-only or it could switch the node to
274 * read-only because BDRV_O_AUTO_RDONLY is set.
276 * Returns -EACCES if the node is read-write and BDRV_O_AUTO_RDONLY is not set
277 * or bdrv_can_set_read_only() forbids making the node read-only. If @errmsg
278 * is not NULL, it is used as the error message for the Error object.
280 int bdrv_apply_auto_read_only(BlockDriverState
*bs
, const char *errmsg
,
285 if (!(bs
->open_flags
& BDRV_O_RDWR
)) {
288 if (!(bs
->open_flags
& BDRV_O_AUTO_RDONLY
)) {
292 ret
= bdrv_can_set_read_only(bs
, true, false, NULL
);
297 bs
->read_only
= true;
298 bs
->open_flags
&= ~BDRV_O_RDWR
;
303 error_setg(errp
, "%s", errmsg ?
: "Image is read-only");
308 * If @backing is empty, this function returns NULL without setting
309 * @errp. In all other cases, NULL will only be returned with @errp
312 * Therefore, a return value of NULL without @errp set means that
313 * there is no backing file; if @errp is set, there is one but its
314 * absolute filename cannot be generated.
316 char *bdrv_get_full_backing_filename_from_filename(const char *backed
,
320 if (backing
[0] == '\0') {
322 } else if (path_has_protocol(backing
) || path_is_absolute(backing
)) {
323 return g_strdup(backing
);
324 } else if (backed
[0] == '\0' || strstart(backed
, "json:", NULL
)) {
325 error_setg(errp
, "Cannot use relative backing file names for '%s'",
329 return path_combine(backed
, backing
);
334 * If @filename is empty or NULL, this function returns NULL without
335 * setting @errp. In all other cases, NULL will only be returned with
338 static char *bdrv_make_absolute_filename(BlockDriverState
*relative_to
,
339 const char *filename
, Error
**errp
)
341 char *dir
, *full_name
;
343 if (!filename
|| filename
[0] == '\0') {
345 } else if (path_has_protocol(filename
) || path_is_absolute(filename
)) {
346 return g_strdup(filename
);
349 dir
= bdrv_dirname(relative_to
, errp
);
354 full_name
= g_strconcat(dir
, filename
, NULL
);
359 char *bdrv_get_full_backing_filename(BlockDriverState
*bs
, Error
**errp
)
361 return bdrv_make_absolute_filename(bs
, bs
->backing_file
, errp
);
364 void bdrv_register(BlockDriver
*bdrv
)
366 QLIST_INSERT_HEAD(&bdrv_drivers
, bdrv
, list
);
369 BlockDriverState
*bdrv_new(void)
371 BlockDriverState
*bs
;
374 bs
= g_new0(BlockDriverState
, 1);
375 QLIST_INIT(&bs
->dirty_bitmaps
);
376 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
377 QLIST_INIT(&bs
->op_blockers
[i
]);
379 notifier_with_return_list_init(&bs
->before_write_notifiers
);
380 qemu_co_mutex_init(&bs
->reqs_lock
);
381 qemu_mutex_init(&bs
->dirty_bitmap_mutex
);
383 bs
->aio_context
= qemu_get_aio_context();
385 qemu_co_queue_init(&bs
->flush_queue
);
387 for (i
= 0; i
< bdrv_drain_all_count
; i
++) {
388 bdrv_drained_begin(bs
);
391 QTAILQ_INSERT_TAIL(&all_bdrv_states
, bs
, bs_list
);
396 static BlockDriver
*bdrv_do_find_format(const char *format_name
)
400 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
401 if (!strcmp(drv1
->format_name
, format_name
)) {
409 BlockDriver
*bdrv_find_format(const char *format_name
)
414 drv1
= bdrv_do_find_format(format_name
);
419 /* The driver isn't registered, maybe we need to load a module */
420 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
421 if (!strcmp(block_driver_modules
[i
].format_name
, format_name
)) {
422 block_module_load_one(block_driver_modules
[i
].library_name
);
427 return bdrv_do_find_format(format_name
);
430 static int bdrv_format_is_whitelisted(const char *format_name
, bool read_only
)
432 static const char *whitelist_rw
[] = {
433 CONFIG_BDRV_RW_WHITELIST
435 static const char *whitelist_ro
[] = {
436 CONFIG_BDRV_RO_WHITELIST
440 if (!whitelist_rw
[0] && !whitelist_ro
[0]) {
441 return 1; /* no whitelist, anything goes */
444 for (p
= whitelist_rw
; *p
; p
++) {
445 if (!strcmp(format_name
, *p
)) {
450 for (p
= whitelist_ro
; *p
; p
++) {
451 if (!strcmp(format_name
, *p
)) {
459 int bdrv_is_whitelisted(BlockDriver
*drv
, bool read_only
)
461 return bdrv_format_is_whitelisted(drv
->format_name
, read_only
);
464 bool bdrv_uses_whitelist(void)
466 return use_bdrv_whitelist
;
469 typedef struct CreateCo
{
477 static void coroutine_fn
bdrv_create_co_entry(void *opaque
)
479 Error
*local_err
= NULL
;
482 CreateCo
*cco
= opaque
;
485 ret
= cco
->drv
->bdrv_co_create_opts(cco
->filename
, cco
->opts
, &local_err
);
486 error_propagate(&cco
->err
, local_err
);
490 int bdrv_create(BlockDriver
*drv
, const char* filename
,
491 QemuOpts
*opts
, Error
**errp
)
498 .filename
= g_strdup(filename
),
504 if (!drv
->bdrv_co_create_opts
) {
505 error_setg(errp
, "Driver '%s' does not support image creation", drv
->format_name
);
510 if (qemu_in_coroutine()) {
511 /* Fast-path if already in coroutine context */
512 bdrv_create_co_entry(&cco
);
514 co
= qemu_coroutine_create(bdrv_create_co_entry
, &cco
);
515 qemu_coroutine_enter(co
);
516 while (cco
.ret
== NOT_DONE
) {
517 aio_poll(qemu_get_aio_context(), true);
524 error_propagate(errp
, cco
.err
);
526 error_setg_errno(errp
, -ret
, "Could not create image");
531 g_free(cco
.filename
);
536 * Helper function for bdrv_create_file_fallback(): Resize @blk to at
537 * least the given @minimum_size.
539 * On success, return @blk's actual length.
540 * Otherwise, return -errno.
542 static int64_t create_file_fallback_truncate(BlockBackend
*blk
,
543 int64_t minimum_size
, Error
**errp
)
545 Error
*local_err
= NULL
;
549 ret
= blk_truncate(blk
, minimum_size
, false, PREALLOC_MODE_OFF
, &local_err
);
550 if (ret
< 0 && ret
!= -ENOTSUP
) {
551 error_propagate(errp
, local_err
);
555 size
= blk_getlength(blk
);
557 error_free(local_err
);
558 error_setg_errno(errp
, -size
,
559 "Failed to inquire the new image file's length");
563 if (size
< minimum_size
) {
564 /* Need to grow the image, but we failed to do that */
565 error_propagate(errp
, local_err
);
569 error_free(local_err
);
576 * Helper function for bdrv_create_file_fallback(): Zero the first
577 * sector to remove any potentially pre-existing image header.
579 static int create_file_fallback_zero_first_sector(BlockBackend
*blk
,
580 int64_t current_size
,
583 int64_t bytes_to_clear
;
586 bytes_to_clear
= MIN(current_size
, BDRV_SECTOR_SIZE
);
587 if (bytes_to_clear
) {
588 ret
= blk_pwrite_zeroes(blk
, 0, bytes_to_clear
, BDRV_REQ_MAY_UNMAP
);
590 error_setg_errno(errp
, -ret
,
591 "Failed to clear the new image's first sector");
599 static int bdrv_create_file_fallback(const char *filename
, BlockDriver
*drv
,
600 QemuOpts
*opts
, Error
**errp
)
606 PreallocMode prealloc
;
607 Error
*local_err
= NULL
;
610 size
= qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0);
611 buf
= qemu_opt_get_del(opts
, BLOCK_OPT_PREALLOC
);
612 prealloc
= qapi_enum_parse(&PreallocMode_lookup
, buf
,
613 PREALLOC_MODE_OFF
, &local_err
);
616 error_propagate(errp
, local_err
);
620 if (prealloc
!= PREALLOC_MODE_OFF
) {
621 error_setg(errp
, "Unsupported preallocation mode '%s'",
622 PreallocMode_str(prealloc
));
626 options
= qdict_new();
627 qdict_put_str(options
, "driver", drv
->format_name
);
629 blk
= blk_new_open(filename
, NULL
, options
,
630 BDRV_O_RDWR
| BDRV_O_RESIZE
, errp
);
632 error_prepend(errp
, "Protocol driver '%s' does not support image "
633 "creation, and opening the image failed: ",
638 size
= create_file_fallback_truncate(blk
, size
, errp
);
644 ret
= create_file_fallback_zero_first_sector(blk
, size
, errp
);
655 int bdrv_create_file(const char *filename
, QemuOpts
*opts
, Error
**errp
)
659 drv
= bdrv_find_protocol(filename
, true, errp
);
664 if (drv
->bdrv_co_create_opts
) {
665 return bdrv_create(drv
, filename
, opts
, errp
);
667 return bdrv_create_file_fallback(filename
, drv
, opts
, errp
);
672 * Try to get @bs's logical and physical block size.
673 * On success, store them in @bsz struct and return 0.
674 * On failure return -errno.
675 * @bs must not be empty.
677 int bdrv_probe_blocksizes(BlockDriverState
*bs
, BlockSizes
*bsz
)
679 BlockDriver
*drv
= bs
->drv
;
681 if (drv
&& drv
->bdrv_probe_blocksizes
) {
682 return drv
->bdrv_probe_blocksizes(bs
, bsz
);
683 } else if (drv
&& drv
->is_filter
&& bs
->file
) {
684 return bdrv_probe_blocksizes(bs
->file
->bs
, bsz
);
691 * Try to get @bs's geometry (cyls, heads, sectors).
692 * On success, store them in @geo struct and return 0.
693 * On failure return -errno.
694 * @bs must not be empty.
696 int bdrv_probe_geometry(BlockDriverState
*bs
, HDGeometry
*geo
)
698 BlockDriver
*drv
= bs
->drv
;
700 if (drv
&& drv
->bdrv_probe_geometry
) {
701 return drv
->bdrv_probe_geometry(bs
, geo
);
702 } else if (drv
&& drv
->is_filter
&& bs
->file
) {
703 return bdrv_probe_geometry(bs
->file
->bs
, geo
);
710 * Create a uniquely-named empty temporary file.
711 * Return 0 upon success, otherwise a negative errno value.
713 int get_tmp_filename(char *filename
, int size
)
716 char temp_dir
[MAX_PATH
];
717 /* GetTempFileName requires that its output buffer (4th param)
718 have length MAX_PATH or greater. */
719 assert(size
>= MAX_PATH
);
720 return (GetTempPath(MAX_PATH
, temp_dir
)
721 && GetTempFileName(temp_dir
, "qem", 0, filename
)
722 ?
0 : -GetLastError());
726 tmpdir
= getenv("TMPDIR");
730 if (snprintf(filename
, size
, "%s/vl.XXXXXX", tmpdir
) >= size
) {
733 fd
= mkstemp(filename
);
737 if (close(fd
) != 0) {
746 * Detect host devices. By convention, /dev/cdrom[N] is always
747 * recognized as a host CDROM.
749 static BlockDriver
*find_hdev_driver(const char *filename
)
751 int score_max
= 0, score
;
752 BlockDriver
*drv
= NULL
, *d
;
754 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
755 if (d
->bdrv_probe_device
) {
756 score
= d
->bdrv_probe_device(filename
);
757 if (score
> score_max
) {
767 static BlockDriver
*bdrv_do_find_protocol(const char *protocol
)
771 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
772 if (drv1
->protocol_name
&& !strcmp(drv1
->protocol_name
, protocol
)) {
780 BlockDriver
*bdrv_find_protocol(const char *filename
,
781 bool allow_protocol_prefix
,
790 /* TODO Drivers without bdrv_file_open must be specified explicitly */
793 * XXX(hch): we really should not let host device detection
794 * override an explicit protocol specification, but moving this
795 * later breaks access to device names with colons in them.
796 * Thanks to the brain-dead persistent naming schemes on udev-
797 * based Linux systems those actually are quite common.
799 drv1
= find_hdev_driver(filename
);
804 if (!path_has_protocol(filename
) || !allow_protocol_prefix
) {
808 p
= strchr(filename
, ':');
811 if (len
> sizeof(protocol
) - 1)
812 len
= sizeof(protocol
) - 1;
813 memcpy(protocol
, filename
, len
);
814 protocol
[len
] = '\0';
816 drv1
= bdrv_do_find_protocol(protocol
);
821 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
822 if (block_driver_modules
[i
].protocol_name
&&
823 !strcmp(block_driver_modules
[i
].protocol_name
, protocol
)) {
824 block_module_load_one(block_driver_modules
[i
].library_name
);
829 drv1
= bdrv_do_find_protocol(protocol
);
831 error_setg(errp
, "Unknown protocol '%s'", protocol
);
837 * Guess image format by probing its contents.
838 * This is not a good idea when your image is raw (CVE-2008-2004), but
839 * we do it anyway for backward compatibility.
841 * @buf contains the image's first @buf_size bytes.
842 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
843 * but can be smaller if the image file is smaller)
844 * @filename is its filename.
846 * For all block drivers, call the bdrv_probe() method to get its
848 * Return the first block driver with the highest probing score.
850 BlockDriver
*bdrv_probe_all(const uint8_t *buf
, int buf_size
,
851 const char *filename
)
853 int score_max
= 0, score
;
854 BlockDriver
*drv
= NULL
, *d
;
856 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
858 score
= d
->bdrv_probe(buf
, buf_size
, filename
);
859 if (score
> score_max
) {
869 static int find_image_format(BlockBackend
*file
, const char *filename
,
870 BlockDriver
**pdrv
, Error
**errp
)
873 uint8_t buf
[BLOCK_PROBE_BUF_SIZE
];
876 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
877 if (blk_is_sg(file
) || !blk_is_inserted(file
) || blk_getlength(file
) == 0) {
882 ret
= blk_pread(file
, 0, buf
, sizeof(buf
));
884 error_setg_errno(errp
, -ret
, "Could not read image for determining its "
890 drv
= bdrv_probe_all(buf
, ret
, filename
);
892 error_setg(errp
, "Could not determine image format: No compatible "
901 * Set the current 'total_sectors' value
902 * Return 0 on success, -errno on error.
904 int refresh_total_sectors(BlockDriverState
*bs
, int64_t hint
)
906 BlockDriver
*drv
= bs
->drv
;
912 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
916 /* query actual device if possible, otherwise just trust the hint */
917 if (drv
->bdrv_getlength
) {
918 int64_t length
= drv
->bdrv_getlength(bs
);
922 hint
= DIV_ROUND_UP(length
, BDRV_SECTOR_SIZE
);
925 bs
->total_sectors
= hint
;
930 * Combines a QDict of new block driver @options with any missing options taken
931 * from @old_options, so that leaving out an option defaults to its old value.
933 static void bdrv_join_options(BlockDriverState
*bs
, QDict
*options
,
936 if (bs
->drv
&& bs
->drv
->bdrv_join_options
) {
937 bs
->drv
->bdrv_join_options(options
, old_options
);
939 qdict_join(options
, old_options
, false);
943 static BlockdevDetectZeroesOptions
bdrv_parse_detect_zeroes(QemuOpts
*opts
,
947 Error
*local_err
= NULL
;
948 char *value
= qemu_opt_get_del(opts
, "detect-zeroes");
949 BlockdevDetectZeroesOptions detect_zeroes
=
950 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup
, value
,
951 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF
, &local_err
);
954 error_propagate(errp
, local_err
);
955 return detect_zeroes
;
958 if (detect_zeroes
== BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP
&&
959 !(open_flags
& BDRV_O_UNMAP
))
961 error_setg(errp
, "setting detect-zeroes to unmap is not allowed "
962 "without setting discard operation to unmap");
965 return detect_zeroes
;
969 * Set open flags for aio engine
971 * Return 0 on success, -1 if the engine specified is invalid
973 int bdrv_parse_aio(const char *mode
, int *flags
)
975 if (!strcmp(mode
, "threads")) {
976 /* do nothing, default */
977 } else if (!strcmp(mode
, "native")) {
978 *flags
|= BDRV_O_NATIVE_AIO
;
979 #ifdef CONFIG_LINUX_IO_URING
980 } else if (!strcmp(mode
, "io_uring")) {
981 *flags
|= BDRV_O_IO_URING
;
991 * Set open flags for a given discard mode
993 * Return 0 on success, -1 if the discard mode was invalid.
995 int bdrv_parse_discard_flags(const char *mode
, int *flags
)
997 *flags
&= ~BDRV_O_UNMAP
;
999 if (!strcmp(mode
, "off") || !strcmp(mode
, "ignore")) {
1001 } else if (!strcmp(mode
, "on") || !strcmp(mode
, "unmap")) {
1002 *flags
|= BDRV_O_UNMAP
;
1011 * Set open flags for a given cache mode
1013 * Return 0 on success, -1 if the cache mode was invalid.
1015 int bdrv_parse_cache_mode(const char *mode
, int *flags
, bool *writethrough
)
1017 *flags
&= ~BDRV_O_CACHE_MASK
;
1019 if (!strcmp(mode
, "off") || !strcmp(mode
, "none")) {
1020 *writethrough
= false;
1021 *flags
|= BDRV_O_NOCACHE
;
1022 } else if (!strcmp(mode
, "directsync")) {
1023 *writethrough
= true;
1024 *flags
|= BDRV_O_NOCACHE
;
1025 } else if (!strcmp(mode
, "writeback")) {
1026 *writethrough
= false;
1027 } else if (!strcmp(mode
, "unsafe")) {
1028 *writethrough
= false;
1029 *flags
|= BDRV_O_NO_FLUSH
;
1030 } else if (!strcmp(mode
, "writethrough")) {
1031 *writethrough
= true;
1039 static char *bdrv_child_get_parent_desc(BdrvChild
*c
)
1041 BlockDriverState
*parent
= c
->opaque
;
1042 return g_strdup(bdrv_get_device_or_node_name(parent
));
1045 static void bdrv_child_cb_drained_begin(BdrvChild
*child
)
1047 BlockDriverState
*bs
= child
->opaque
;
1048 bdrv_do_drained_begin_quiesce(bs
, NULL
, false);
1051 static bool bdrv_child_cb_drained_poll(BdrvChild
*child
)
1053 BlockDriverState
*bs
= child
->opaque
;
1054 return bdrv_drain_poll(bs
, false, NULL
, false);
1057 static void bdrv_child_cb_drained_end(BdrvChild
*child
,
1058 int *drained_end_counter
)
1060 BlockDriverState
*bs
= child
->opaque
;
1061 bdrv_drained_end_no_poll(bs
, drained_end_counter
);
1064 static void bdrv_child_cb_attach(BdrvChild
*child
)
1066 BlockDriverState
*bs
= child
->opaque
;
1067 bdrv_apply_subtree_drain(child
, bs
);
1070 static void bdrv_child_cb_detach(BdrvChild
*child
)
1072 BlockDriverState
*bs
= child
->opaque
;
1073 bdrv_unapply_subtree_drain(child
, bs
);
1076 static int bdrv_child_cb_inactivate(BdrvChild
*child
)
1078 BlockDriverState
*bs
= child
->opaque
;
1079 assert(bs
->open_flags
& BDRV_O_INACTIVE
);
1083 static bool bdrv_child_cb_can_set_aio_ctx(BdrvChild
*child
, AioContext
*ctx
,
1084 GSList
**ignore
, Error
**errp
)
1086 BlockDriverState
*bs
= child
->opaque
;
1087 return bdrv_can_set_aio_context(bs
, ctx
, ignore
, errp
);
1090 static void bdrv_child_cb_set_aio_ctx(BdrvChild
*child
, AioContext
*ctx
,
1093 BlockDriverState
*bs
= child
->opaque
;
1094 return bdrv_set_aio_context_ignore(bs
, ctx
, ignore
);
1098 * Returns the options and flags that a temporary snapshot should get, based on
1099 * the originally requested flags (the originally requested image will have
1100 * flags like a backing file)
1102 static void bdrv_temp_snapshot_options(int *child_flags
, QDict
*child_options
,
1103 int parent_flags
, QDict
*parent_options
)
1105 *child_flags
= (parent_flags
& ~BDRV_O_SNAPSHOT
) | BDRV_O_TEMPORARY
;
1107 /* For temporary files, unconditional cache=unsafe is fine */
1108 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_DIRECT
, "off");
1109 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_NO_FLUSH
, "on");
1111 /* Copy the read-only and discard options from the parent */
1112 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1113 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_DISCARD
);
1115 /* aio=native doesn't work for cache.direct=off, so disable it for the
1116 * temporary snapshot */
1117 *child_flags
&= ~BDRV_O_NATIVE_AIO
;
1121 * Returns the options and flags that bs->file should get if a protocol driver
1122 * is expected, based on the given options and flags for the parent BDS
1124 static void bdrv_inherited_options(int *child_flags
, QDict
*child_options
,
1125 int parent_flags
, QDict
*parent_options
)
1127 int flags
= parent_flags
;
1129 /* Enable protocol handling, disable format probing for bs->file */
1130 flags
|= BDRV_O_PROTOCOL
;
1132 /* If the cache mode isn't explicitly set, inherit direct and no-flush from
1134 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_DIRECT
);
1135 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_NO_FLUSH
);
1136 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_FORCE_SHARE
);
1138 /* Inherit the read-only option from the parent if it's not set */
1139 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1140 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_AUTO_READ_ONLY
);
1142 /* Our block drivers take care to send flushes and respect unmap policy,
1143 * so we can default to enable both on lower layers regardless of the
1144 * corresponding parent options. */
1145 qdict_set_default_str(child_options
, BDRV_OPT_DISCARD
, "unmap");
1147 /* Clear flags that only apply to the top layer */
1148 flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_COPY_ON_READ
|
1151 *child_flags
= flags
;
1154 const BdrvChildRole child_file
= {
1155 .parent_is_bds
= true,
1156 .get_parent_desc
= bdrv_child_get_parent_desc
,
1157 .inherit_options
= bdrv_inherited_options
,
1158 .drained_begin
= bdrv_child_cb_drained_begin
,
1159 .drained_poll
= bdrv_child_cb_drained_poll
,
1160 .drained_end
= bdrv_child_cb_drained_end
,
1161 .attach
= bdrv_child_cb_attach
,
1162 .detach
= bdrv_child_cb_detach
,
1163 .inactivate
= bdrv_child_cb_inactivate
,
1164 .can_set_aio_ctx
= bdrv_child_cb_can_set_aio_ctx
,
1165 .set_aio_ctx
= bdrv_child_cb_set_aio_ctx
,
1169 * Returns the options and flags that bs->file should get if the use of formats
1170 * (and not only protocols) is permitted for it, based on the given options and
1171 * flags for the parent BDS
1173 static void bdrv_inherited_fmt_options(int *child_flags
, QDict
*child_options
,
1174 int parent_flags
, QDict
*parent_options
)
1176 child_file
.inherit_options(child_flags
, child_options
,
1177 parent_flags
, parent_options
);
1179 *child_flags
&= ~(BDRV_O_PROTOCOL
| BDRV_O_NO_IO
);
1182 const BdrvChildRole child_format
= {
1183 .parent_is_bds
= true,
1184 .get_parent_desc
= bdrv_child_get_parent_desc
,
1185 .inherit_options
= bdrv_inherited_fmt_options
,
1186 .drained_begin
= bdrv_child_cb_drained_begin
,
1187 .drained_poll
= bdrv_child_cb_drained_poll
,
1188 .drained_end
= bdrv_child_cb_drained_end
,
1189 .attach
= bdrv_child_cb_attach
,
1190 .detach
= bdrv_child_cb_detach
,
1191 .inactivate
= bdrv_child_cb_inactivate
,
1192 .can_set_aio_ctx
= bdrv_child_cb_can_set_aio_ctx
,
1193 .set_aio_ctx
= bdrv_child_cb_set_aio_ctx
,
1196 static void bdrv_backing_attach(BdrvChild
*c
)
1198 BlockDriverState
*parent
= c
->opaque
;
1199 BlockDriverState
*backing_hd
= c
->bs
;
1201 assert(!parent
->backing_blocker
);
1202 error_setg(&parent
->backing_blocker
,
1203 "node is used as backing hd of '%s'",
1204 bdrv_get_device_or_node_name(parent
));
1206 bdrv_refresh_filename(backing_hd
);
1208 parent
->open_flags
&= ~BDRV_O_NO_BACKING
;
1209 pstrcpy(parent
->backing_file
, sizeof(parent
->backing_file
),
1210 backing_hd
->filename
);
1211 pstrcpy(parent
->backing_format
, sizeof(parent
->backing_format
),
1212 backing_hd
->drv ? backing_hd
->drv
->format_name
: "");
1214 bdrv_op_block_all(backing_hd
, parent
->backing_blocker
);
1215 /* Otherwise we won't be able to commit or stream */
1216 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_COMMIT_TARGET
,
1217 parent
->backing_blocker
);
1218 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_STREAM
,
1219 parent
->backing_blocker
);
1221 * We do backup in 3 ways:
1223 * The target bs is new opened, and the source is top BDS
1224 * 2. blockdev backup
1225 * Both the source and the target are top BDSes.
1226 * 3. internal backup(used for block replication)
1227 * Both the source and the target are backing file
1229 * In case 1 and 2, neither the source nor the target is the backing file.
1230 * In case 3, we will block the top BDS, so there is only one block job
1231 * for the top BDS and its backing chain.
1233 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_SOURCE
,
1234 parent
->backing_blocker
);
1235 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_TARGET
,
1236 parent
->backing_blocker
);
1238 bdrv_child_cb_attach(c
);
1241 static void bdrv_backing_detach(BdrvChild
*c
)
1243 BlockDriverState
*parent
= c
->opaque
;
1245 assert(parent
->backing_blocker
);
1246 bdrv_op_unblock_all(c
->bs
, parent
->backing_blocker
);
1247 error_free(parent
->backing_blocker
);
1248 parent
->backing_blocker
= NULL
;
1250 bdrv_child_cb_detach(c
);
1254 * Returns the options and flags that bs->backing should get, based on the
1255 * given options and flags for the parent BDS
1257 static void bdrv_backing_options(int *child_flags
, QDict
*child_options
,
1258 int parent_flags
, QDict
*parent_options
)
1260 int flags
= parent_flags
;
1262 /* The cache mode is inherited unmodified for backing files; except WCE,
1263 * which is only applied on the top level (BlockBackend) */
1264 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_DIRECT
);
1265 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_NO_FLUSH
);
1266 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_FORCE_SHARE
);
1268 /* backing files always opened read-only */
1269 qdict_set_default_str(child_options
, BDRV_OPT_READ_ONLY
, "on");
1270 qdict_set_default_str(child_options
, BDRV_OPT_AUTO_READ_ONLY
, "off");
1271 flags
&= ~BDRV_O_COPY_ON_READ
;
1273 /* snapshot=on is handled on the top layer */
1274 flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_TEMPORARY
);
1276 *child_flags
= flags
;
1279 static int bdrv_backing_update_filename(BdrvChild
*c
, BlockDriverState
*base
,
1280 const char *filename
, Error
**errp
)
1282 BlockDriverState
*parent
= c
->opaque
;
1283 bool read_only
= bdrv_is_read_only(parent
);
1287 ret
= bdrv_reopen_set_read_only(parent
, false, errp
);
1293 ret
= bdrv_change_backing_file(parent
, filename
,
1294 base
->drv ? base
->drv
->format_name
: "");
1296 error_setg_errno(errp
, -ret
, "Could not update backing file link");
1300 bdrv_reopen_set_read_only(parent
, true, NULL
);
1306 const BdrvChildRole child_backing
= {
1307 .parent_is_bds
= true,
1308 .get_parent_desc
= bdrv_child_get_parent_desc
,
1309 .attach
= bdrv_backing_attach
,
1310 .detach
= bdrv_backing_detach
,
1311 .inherit_options
= bdrv_backing_options
,
1312 .drained_begin
= bdrv_child_cb_drained_begin
,
1313 .drained_poll
= bdrv_child_cb_drained_poll
,
1314 .drained_end
= bdrv_child_cb_drained_end
,
1315 .inactivate
= bdrv_child_cb_inactivate
,
1316 .update_filename
= bdrv_backing_update_filename
,
1317 .can_set_aio_ctx
= bdrv_child_cb_can_set_aio_ctx
,
1318 .set_aio_ctx
= bdrv_child_cb_set_aio_ctx
,
1321 static int bdrv_open_flags(BlockDriverState
*bs
, int flags
)
1323 int open_flags
= flags
;
1326 * Clear flags that are internal to the block layer before opening the
1329 open_flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_PROTOCOL
);
1334 static void update_flags_from_options(int *flags
, QemuOpts
*opts
)
1336 *flags
&= ~(BDRV_O_CACHE_MASK
| BDRV_O_RDWR
| BDRV_O_AUTO_RDONLY
);
1338 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_NO_FLUSH
, false)) {
1339 *flags
|= BDRV_O_NO_FLUSH
;
1342 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_DIRECT
, false)) {
1343 *flags
|= BDRV_O_NOCACHE
;
1346 if (!qemu_opt_get_bool_del(opts
, BDRV_OPT_READ_ONLY
, false)) {
1347 *flags
|= BDRV_O_RDWR
;
1350 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_AUTO_READ_ONLY
, false)) {
1351 *flags
|= BDRV_O_AUTO_RDONLY
;
1355 static void update_options_from_flags(QDict
*options
, int flags
)
1357 if (!qdict_haskey(options
, BDRV_OPT_CACHE_DIRECT
)) {
1358 qdict_put_bool(options
, BDRV_OPT_CACHE_DIRECT
, flags
& BDRV_O_NOCACHE
);
1360 if (!qdict_haskey(options
, BDRV_OPT_CACHE_NO_FLUSH
)) {
1361 qdict_put_bool(options
, BDRV_OPT_CACHE_NO_FLUSH
,
1362 flags
& BDRV_O_NO_FLUSH
);
1364 if (!qdict_haskey(options
, BDRV_OPT_READ_ONLY
)) {
1365 qdict_put_bool(options
, BDRV_OPT_READ_ONLY
, !(flags
& BDRV_O_RDWR
));
1367 if (!qdict_haskey(options
, BDRV_OPT_AUTO_READ_ONLY
)) {
1368 qdict_put_bool(options
, BDRV_OPT_AUTO_READ_ONLY
,
1369 flags
& BDRV_O_AUTO_RDONLY
);
1373 static void bdrv_assign_node_name(BlockDriverState
*bs
,
1374 const char *node_name
,
1377 char *gen_node_name
= NULL
;
1380 node_name
= gen_node_name
= id_generate(ID_BLOCK
);
1381 } else if (!id_wellformed(node_name
)) {
1383 * Check for empty string or invalid characters, but not if it is
1384 * generated (generated names use characters not available to the user)
1386 error_setg(errp
, "Invalid node name");
1390 /* takes care of avoiding namespaces collisions */
1391 if (blk_by_name(node_name
)) {
1392 error_setg(errp
, "node-name=%s is conflicting with a device id",
1397 /* takes care of avoiding duplicates node names */
1398 if (bdrv_find_node(node_name
)) {
1399 error_setg(errp
, "Duplicate node name");
1403 /* Make sure that the node name isn't truncated */
1404 if (strlen(node_name
) >= sizeof(bs
->node_name
)) {
1405 error_setg(errp
, "Node name too long");
1409 /* copy node name into the bs and insert it into the graph list */
1410 pstrcpy(bs
->node_name
, sizeof(bs
->node_name
), node_name
);
1411 QTAILQ_INSERT_TAIL(&graph_bdrv_states
, bs
, node_list
);
1413 g_free(gen_node_name
);
1416 static int bdrv_open_driver(BlockDriverState
*bs
, BlockDriver
*drv
,
1417 const char *node_name
, QDict
*options
,
1418 int open_flags
, Error
**errp
)
1420 Error
*local_err
= NULL
;
1423 bdrv_assign_node_name(bs
, node_name
, &local_err
);
1425 error_propagate(errp
, local_err
);
1430 bs
->read_only
= !(bs
->open_flags
& BDRV_O_RDWR
);
1431 bs
->opaque
= g_malloc0(drv
->instance_size
);
1433 if (drv
->bdrv_file_open
) {
1434 assert(!drv
->bdrv_needs_filename
|| bs
->filename
[0]);
1435 ret
= drv
->bdrv_file_open(bs
, options
, open_flags
, &local_err
);
1436 } else if (drv
->bdrv_open
) {
1437 ret
= drv
->bdrv_open(bs
, options
, open_flags
, &local_err
);
1444 error_propagate(errp
, local_err
);
1445 } else if (bs
->filename
[0]) {
1446 error_setg_errno(errp
, -ret
, "Could not open '%s'", bs
->filename
);
1448 error_setg_errno(errp
, -ret
, "Could not open image");
1453 ret
= refresh_total_sectors(bs
, bs
->total_sectors
);
1455 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
1459 bdrv_refresh_limits(bs
, &local_err
);
1461 error_propagate(errp
, local_err
);
1465 assert(bdrv_opt_mem_align(bs
) != 0);
1466 assert(bdrv_min_mem_align(bs
) != 0);
1467 assert(is_power_of_2(bs
->bl
.request_alignment
));
1469 for (i
= 0; i
< bs
->quiesce_counter
; i
++) {
1470 if (drv
->bdrv_co_drain_begin
) {
1471 drv
->bdrv_co_drain_begin(bs
);
1478 if (bs
->file
!= NULL
) {
1479 bdrv_unref_child(bs
, bs
->file
);
1487 BlockDriverState
*bdrv_new_open_driver(BlockDriver
*drv
, const char *node_name
,
1488 int flags
, Error
**errp
)
1490 BlockDriverState
*bs
;
1494 bs
->open_flags
= flags
;
1495 bs
->explicit_options
= qdict_new();
1496 bs
->options
= qdict_new();
1499 update_options_from_flags(bs
->options
, flags
);
1501 ret
= bdrv_open_driver(bs
, drv
, node_name
, bs
->options
, flags
, errp
);
1503 qobject_unref(bs
->explicit_options
);
1504 bs
->explicit_options
= NULL
;
1505 qobject_unref(bs
->options
);
1514 QemuOptsList bdrv_runtime_opts
= {
1515 .name
= "bdrv_common",
1516 .head
= QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts
.head
),
1519 .name
= "node-name",
1520 .type
= QEMU_OPT_STRING
,
1521 .help
= "Node name of the block device node",
1525 .type
= QEMU_OPT_STRING
,
1526 .help
= "Block driver to use for the node",
1529 .name
= BDRV_OPT_CACHE_DIRECT
,
1530 .type
= QEMU_OPT_BOOL
,
1531 .help
= "Bypass software writeback cache on the host",
1534 .name
= BDRV_OPT_CACHE_NO_FLUSH
,
1535 .type
= QEMU_OPT_BOOL
,
1536 .help
= "Ignore flush requests",
1539 .name
= BDRV_OPT_READ_ONLY
,
1540 .type
= QEMU_OPT_BOOL
,
1541 .help
= "Node is opened in read-only mode",
1544 .name
= BDRV_OPT_AUTO_READ_ONLY
,
1545 .type
= QEMU_OPT_BOOL
,
1546 .help
= "Node can become read-only if opening read-write fails",
1549 .name
= "detect-zeroes",
1550 .type
= QEMU_OPT_STRING
,
1551 .help
= "try to optimize zero writes (off, on, unmap)",
1554 .name
= BDRV_OPT_DISCARD
,
1555 .type
= QEMU_OPT_STRING
,
1556 .help
= "discard operation (ignore/off, unmap/on)",
1559 .name
= BDRV_OPT_FORCE_SHARE
,
1560 .type
= QEMU_OPT_BOOL
,
1561 .help
= "always accept other writers (default: off)",
1563 { /* end of list */ }
1567 static QemuOptsList fallback_create_opts
= {
1568 .name
= "fallback-create-opts",
1569 .head
= QTAILQ_HEAD_INITIALIZER(fallback_create_opts
.head
),
1572 .name
= BLOCK_OPT_SIZE
,
1573 .type
= QEMU_OPT_SIZE
,
1574 .help
= "Virtual disk size"
1577 .name
= BLOCK_OPT_PREALLOC
,
1578 .type
= QEMU_OPT_STRING
,
1579 .help
= "Preallocation mode (allowed values: off)"
1581 { /* end of list */ }
1586 * Common part for opening disk images and files
1588 * Removes all processed options from *options.
1590 static int bdrv_open_common(BlockDriverState
*bs
, BlockBackend
*file
,
1591 QDict
*options
, Error
**errp
)
1593 int ret
, open_flags
;
1594 const char *filename
;
1595 const char *driver_name
= NULL
;
1596 const char *node_name
= NULL
;
1597 const char *discard
;
1600 Error
*local_err
= NULL
;
1602 assert(bs
->file
== NULL
);
1603 assert(options
!= NULL
&& bs
->options
!= options
);
1605 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
1606 qemu_opts_absorb_qdict(opts
, options
, &local_err
);
1608 error_propagate(errp
, local_err
);
1613 update_flags_from_options(&bs
->open_flags
, opts
);
1615 driver_name
= qemu_opt_get(opts
, "driver");
1616 drv
= bdrv_find_format(driver_name
);
1617 assert(drv
!= NULL
);
1619 bs
->force_share
= qemu_opt_get_bool(opts
, BDRV_OPT_FORCE_SHARE
, false);
1621 if (bs
->force_share
&& (bs
->open_flags
& BDRV_O_RDWR
)) {
1623 BDRV_OPT_FORCE_SHARE
1624 "=on can only be used with read-only images");
1630 bdrv_refresh_filename(blk_bs(file
));
1631 filename
= blk_bs(file
)->filename
;
1634 * Caution: while qdict_get_try_str() is fine, getting
1635 * non-string types would require more care. When @options
1636 * come from -blockdev or blockdev_add, its members are typed
1637 * according to the QAPI schema, but when they come from
1638 * -drive, they're all QString.
1640 filename
= qdict_get_try_str(options
, "filename");
1643 if (drv
->bdrv_needs_filename
&& (!filename
|| !filename
[0])) {
1644 error_setg(errp
, "The '%s' block driver requires a file name",
1650 trace_bdrv_open_common(bs
, filename ?
: "", bs
->open_flags
,
1653 bs
->read_only
= !(bs
->open_flags
& BDRV_O_RDWR
);
1655 if (use_bdrv_whitelist
&& !bdrv_is_whitelisted(drv
, bs
->read_only
)) {
1656 if (!bs
->read_only
&& bdrv_is_whitelisted(drv
, true)) {
1657 ret
= bdrv_apply_auto_read_only(bs
, NULL
, NULL
);
1663 !bs
->read_only
&& bdrv_is_whitelisted(drv
, true)
1664 ?
"Driver '%s' can only be used for read-only devices"
1665 : "Driver '%s' is not whitelisted",
1671 /* bdrv_new() and bdrv_close() make it so */
1672 assert(atomic_read(&bs
->copy_on_read
) == 0);
1674 if (bs
->open_flags
& BDRV_O_COPY_ON_READ
) {
1675 if (!bs
->read_only
) {
1676 bdrv_enable_copy_on_read(bs
);
1678 error_setg(errp
, "Can't use copy-on-read on read-only device");
1684 discard
= qemu_opt_get(opts
, BDRV_OPT_DISCARD
);
1685 if (discard
!= NULL
) {
1686 if (bdrv_parse_discard_flags(discard
, &bs
->open_flags
) != 0) {
1687 error_setg(errp
, "Invalid discard option");
1694 bdrv_parse_detect_zeroes(opts
, bs
->open_flags
, &local_err
);
1696 error_propagate(errp
, local_err
);
1701 if (filename
!= NULL
) {
1702 pstrcpy(bs
->filename
, sizeof(bs
->filename
), filename
);
1704 bs
->filename
[0] = '\0';
1706 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
), bs
->filename
);
1708 /* Open the image, either directly or using a protocol */
1709 open_flags
= bdrv_open_flags(bs
, bs
->open_flags
);
1710 node_name
= qemu_opt_get(opts
, "node-name");
1712 assert(!drv
->bdrv_file_open
|| file
== NULL
);
1713 ret
= bdrv_open_driver(bs
, drv
, node_name
, options
, open_flags
, errp
);
1718 qemu_opts_del(opts
);
1722 qemu_opts_del(opts
);
1726 static QDict
*parse_json_filename(const char *filename
, Error
**errp
)
1728 QObject
*options_obj
;
1732 ret
= strstart(filename
, "json:", &filename
);
1735 options_obj
= qobject_from_json(filename
, errp
);
1737 error_prepend(errp
, "Could not parse the JSON options: ");
1741 options
= qobject_to(QDict
, options_obj
);
1743 qobject_unref(options_obj
);
1744 error_setg(errp
, "Invalid JSON object given");
1748 qdict_flatten(options
);
1753 static void parse_json_protocol(QDict
*options
, const char **pfilename
,
1756 QDict
*json_options
;
1757 Error
*local_err
= NULL
;
1759 /* Parse json: pseudo-protocol */
1760 if (!*pfilename
|| !g_str_has_prefix(*pfilename
, "json:")) {
1764 json_options
= parse_json_filename(*pfilename
, &local_err
);
1766 error_propagate(errp
, local_err
);
1770 /* Options given in the filename have lower priority than options
1771 * specified directly */
1772 qdict_join(options
, json_options
, false);
1773 qobject_unref(json_options
);
1778 * Fills in default options for opening images and converts the legacy
1779 * filename/flags pair to option QDict entries.
1780 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1781 * block driver has been specified explicitly.
1783 static int bdrv_fill_options(QDict
**options
, const char *filename
,
1784 int *flags
, Error
**errp
)
1786 const char *drvname
;
1787 bool protocol
= *flags
& BDRV_O_PROTOCOL
;
1788 bool parse_filename
= false;
1789 BlockDriver
*drv
= NULL
;
1790 Error
*local_err
= NULL
;
1793 * Caution: while qdict_get_try_str() is fine, getting non-string
1794 * types would require more care. When @options come from
1795 * -blockdev or blockdev_add, its members are typed according to
1796 * the QAPI schema, but when they come from -drive, they're all
1799 drvname
= qdict_get_try_str(*options
, "driver");
1801 drv
= bdrv_find_format(drvname
);
1803 error_setg(errp
, "Unknown driver '%s'", drvname
);
1806 /* If the user has explicitly specified the driver, this choice should
1807 * override the BDRV_O_PROTOCOL flag */
1808 protocol
= drv
->bdrv_file_open
;
1812 *flags
|= BDRV_O_PROTOCOL
;
1814 *flags
&= ~BDRV_O_PROTOCOL
;
1817 /* Translate cache options from flags into options */
1818 update_options_from_flags(*options
, *flags
);
1820 /* Fetch the file name from the options QDict if necessary */
1821 if (protocol
&& filename
) {
1822 if (!qdict_haskey(*options
, "filename")) {
1823 qdict_put_str(*options
, "filename", filename
);
1824 parse_filename
= true;
1826 error_setg(errp
, "Can't specify 'file' and 'filename' options at "
1832 /* Find the right block driver */
1833 /* See cautionary note on accessing @options above */
1834 filename
= qdict_get_try_str(*options
, "filename");
1836 if (!drvname
&& protocol
) {
1838 drv
= bdrv_find_protocol(filename
, parse_filename
, errp
);
1843 drvname
= drv
->format_name
;
1844 qdict_put_str(*options
, "driver", drvname
);
1846 error_setg(errp
, "Must specify either driver or file");
1851 assert(drv
|| !protocol
);
1853 /* Driver-specific filename parsing */
1854 if (drv
&& drv
->bdrv_parse_filename
&& parse_filename
) {
1855 drv
->bdrv_parse_filename(filename
, *options
, &local_err
);
1857 error_propagate(errp
, local_err
);
1861 if (!drv
->bdrv_needs_filename
) {
1862 qdict_del(*options
, "filename");
1869 static int bdrv_child_check_perm(BdrvChild
*c
, BlockReopenQueue
*q
,
1870 uint64_t perm
, uint64_t shared
,
1871 GSList
*ignore_children
,
1872 bool *tighten_restrictions
, Error
**errp
);
1873 static void bdrv_child_abort_perm_update(BdrvChild
*c
);
1874 static void bdrv_child_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
);
1875 static void bdrv_get_cumulative_perm(BlockDriverState
*bs
, uint64_t *perm
,
1876 uint64_t *shared_perm
);
1878 typedef struct BlockReopenQueueEntry
{
1881 BDRVReopenState state
;
1882 QTAILQ_ENTRY(BlockReopenQueueEntry
) entry
;
1883 } BlockReopenQueueEntry
;
1886 * Return the flags that @bs will have after the reopens in @q have
1887 * successfully completed. If @q is NULL (or @bs is not contained in @q),
1888 * return the current flags.
1890 static int bdrv_reopen_get_flags(BlockReopenQueue
*q
, BlockDriverState
*bs
)
1892 BlockReopenQueueEntry
*entry
;
1895 QTAILQ_FOREACH(entry
, q
, entry
) {
1896 if (entry
->state
.bs
== bs
) {
1897 return entry
->state
.flags
;
1902 return bs
->open_flags
;
1905 /* Returns whether the image file can be written to after the reopen queue @q
1906 * has been successfully applied, or right now if @q is NULL. */
1907 static bool bdrv_is_writable_after_reopen(BlockDriverState
*bs
,
1908 BlockReopenQueue
*q
)
1910 int flags
= bdrv_reopen_get_flags(q
, bs
);
1912 return (flags
& (BDRV_O_RDWR
| BDRV_O_INACTIVE
)) == BDRV_O_RDWR
;
1916 * Return whether the BDS can be written to. This is not necessarily
1917 * the same as !bdrv_is_read_only(bs), as inactivated images may not
1918 * be written to but do not count as read-only images.
1920 bool bdrv_is_writable(BlockDriverState
*bs
)
1922 return bdrv_is_writable_after_reopen(bs
, NULL
);
1925 static void bdrv_child_perm(BlockDriverState
*bs
, BlockDriverState
*child_bs
,
1926 BdrvChild
*c
, const BdrvChildRole
*role
,
1927 BlockReopenQueue
*reopen_queue
,
1928 uint64_t parent_perm
, uint64_t parent_shared
,
1929 uint64_t *nperm
, uint64_t *nshared
)
1931 assert(bs
->drv
&& bs
->drv
->bdrv_child_perm
);
1932 bs
->drv
->bdrv_child_perm(bs
, c
, role
, reopen_queue
,
1933 parent_perm
, parent_shared
,
1935 /* TODO Take force_share from reopen_queue */
1936 if (child_bs
&& child_bs
->force_share
) {
1937 *nshared
= BLK_PERM_ALL
;
1942 * Check whether permissions on this node can be changed in a way that
1943 * @cumulative_perms and @cumulative_shared_perms are the new cumulative
1944 * permissions of all its parents. This involves checking whether all necessary
1945 * permission changes to child nodes can be performed.
1947 * Will set *tighten_restrictions to true if and only if new permissions have to
1948 * be taken or currently shared permissions are to be unshared. Otherwise,
1949 * errors are not fatal as long as the caller accepts that the restrictions
1950 * remain tighter than they need to be. The caller still has to abort the
1952 * @tighten_restrictions cannot be used together with @q: When reopening, we may
1953 * encounter fatal errors even though no restrictions are to be tightened. For
1954 * example, changing a node from RW to RO will fail if the WRITE permission is
1957 * A call to this function must always be followed by a call to bdrv_set_perm()
1958 * or bdrv_abort_perm_update().
1960 static int bdrv_check_perm(BlockDriverState
*bs
, BlockReopenQueue
*q
,
1961 uint64_t cumulative_perms
,
1962 uint64_t cumulative_shared_perms
,
1963 GSList
*ignore_children
,
1964 bool *tighten_restrictions
, Error
**errp
)
1966 BlockDriver
*drv
= bs
->drv
;
1970 assert(!q
|| !tighten_restrictions
);
1972 if (tighten_restrictions
) {
1973 uint64_t current_perms
, current_shared
;
1974 uint64_t added_perms
, removed_shared_perms
;
1976 bdrv_get_cumulative_perm(bs
, ¤t_perms
, ¤t_shared
);
1978 added_perms
= cumulative_perms
& ~current_perms
;
1979 removed_shared_perms
= current_shared
& ~cumulative_shared_perms
;
1981 *tighten_restrictions
= added_perms
|| removed_shared_perms
;
1984 /* Write permissions never work with read-only images */
1985 if ((cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) &&
1986 !bdrv_is_writable_after_reopen(bs
, q
))
1988 if (!bdrv_is_writable_after_reopen(bs
, NULL
)) {
1989 error_setg(errp
, "Block node is read-only");
1991 uint64_t current_perms
, current_shared
;
1992 bdrv_get_cumulative_perm(bs
, ¤t_perms
, ¤t_shared
);
1993 if (current_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) {
1994 error_setg(errp
, "Cannot make block node read-only, there is "
1997 error_setg(errp
, "Cannot make block node read-only and create "
2005 /* Check this node */
2010 if (drv
->bdrv_check_perm
) {
2011 return drv
->bdrv_check_perm(bs
, cumulative_perms
,
2012 cumulative_shared_perms
, errp
);
2015 /* Drivers that never have children can omit .bdrv_child_perm() */
2016 if (!drv
->bdrv_child_perm
) {
2017 assert(QLIST_EMPTY(&bs
->children
));
2021 /* Check all children */
2022 QLIST_FOREACH(c
, &bs
->children
, next
) {
2023 uint64_t cur_perm
, cur_shared
;
2024 bool child_tighten_restr
;
2026 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, q
,
2027 cumulative_perms
, cumulative_shared_perms
,
2028 &cur_perm
, &cur_shared
);
2029 ret
= bdrv_child_check_perm(c
, q
, cur_perm
, cur_shared
, ignore_children
,
2030 tighten_restrictions ?
&child_tighten_restr
2033 if (tighten_restrictions
) {
2034 *tighten_restrictions
|= child_tighten_restr
;
2045 * Notifies drivers that after a previous bdrv_check_perm() call, the
2046 * permission update is not performed and any preparations made for it (e.g.
2047 * taken file locks) need to be undone.
2049 * This function recursively notifies all child nodes.
2051 static void bdrv_abort_perm_update(BlockDriverState
*bs
)
2053 BlockDriver
*drv
= bs
->drv
;
2060 if (drv
->bdrv_abort_perm_update
) {
2061 drv
->bdrv_abort_perm_update(bs
);
2064 QLIST_FOREACH(c
, &bs
->children
, next
) {
2065 bdrv_child_abort_perm_update(c
);
2069 static void bdrv_set_perm(BlockDriverState
*bs
, uint64_t cumulative_perms
,
2070 uint64_t cumulative_shared_perms
)
2072 BlockDriver
*drv
= bs
->drv
;
2079 /* Update this node */
2080 if (drv
->bdrv_set_perm
) {
2081 drv
->bdrv_set_perm(bs
, cumulative_perms
, cumulative_shared_perms
);
2084 /* Drivers that never have children can omit .bdrv_child_perm() */
2085 if (!drv
->bdrv_child_perm
) {
2086 assert(QLIST_EMPTY(&bs
->children
));
2090 /* Update all children */
2091 QLIST_FOREACH(c
, &bs
->children
, next
) {
2092 uint64_t cur_perm
, cur_shared
;
2093 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, NULL
,
2094 cumulative_perms
, cumulative_shared_perms
,
2095 &cur_perm
, &cur_shared
);
2096 bdrv_child_set_perm(c
, cur_perm
, cur_shared
);
2100 static void bdrv_get_cumulative_perm(BlockDriverState
*bs
, uint64_t *perm
,
2101 uint64_t *shared_perm
)
2104 uint64_t cumulative_perms
= 0;
2105 uint64_t cumulative_shared_perms
= BLK_PERM_ALL
;
2107 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
2108 cumulative_perms
|= c
->perm
;
2109 cumulative_shared_perms
&= c
->shared_perm
;
2112 *perm
= cumulative_perms
;
2113 *shared_perm
= cumulative_shared_perms
;
2116 static char *bdrv_child_user_desc(BdrvChild
*c
)
2118 if (c
->role
->get_parent_desc
) {
2119 return c
->role
->get_parent_desc(c
);
2122 return g_strdup("another user");
2125 char *bdrv_perm_names(uint64_t perm
)
2131 { BLK_PERM_CONSISTENT_READ
, "consistent read" },
2132 { BLK_PERM_WRITE
, "write" },
2133 { BLK_PERM_WRITE_UNCHANGED
, "write unchanged" },
2134 { BLK_PERM_RESIZE
, "resize" },
2135 { BLK_PERM_GRAPH_MOD
, "change children" },
2139 GString
*result
= g_string_sized_new(30);
2140 struct perm_name
*p
;
2142 for (p
= permissions
; p
->name
; p
++) {
2143 if (perm
& p
->perm
) {
2144 if (result
->len
> 0) {
2145 g_string_append(result
, ", ");
2147 g_string_append(result
, p
->name
);
2151 return g_string_free(result
, FALSE
);
2155 * Checks whether a new reference to @bs can be added if the new user requires
2156 * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is
2157 * set, the BdrvChild objects in this list are ignored in the calculations;
2158 * this allows checking permission updates for an existing reference.
2160 * See bdrv_check_perm() for the semantics of @tighten_restrictions.
2162 * Needs to be followed by a call to either bdrv_set_perm() or
2163 * bdrv_abort_perm_update(). */
2164 static int bdrv_check_update_perm(BlockDriverState
*bs
, BlockReopenQueue
*q
,
2165 uint64_t new_used_perm
,
2166 uint64_t new_shared_perm
,
2167 GSList
*ignore_children
,
2168 bool *tighten_restrictions
,
2172 uint64_t cumulative_perms
= new_used_perm
;
2173 uint64_t cumulative_shared_perms
= new_shared_perm
;
2175 assert(!q
|| !tighten_restrictions
);
2177 /* There is no reason why anyone couldn't tolerate write_unchanged */
2178 assert(new_shared_perm
& BLK_PERM_WRITE_UNCHANGED
);
2180 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
2181 if (g_slist_find(ignore_children
, c
)) {
2185 if ((new_used_perm
& c
->shared_perm
) != new_used_perm
) {
2186 char *user
= bdrv_child_user_desc(c
);
2187 char *perm_names
= bdrv_perm_names(new_used_perm
& ~c
->shared_perm
);
2189 if (tighten_restrictions
) {
2190 *tighten_restrictions
= true;
2193 error_setg(errp
, "Conflicts with use by %s as '%s', which does not "
2195 user
, c
->name
, perm_names
, bdrv_get_node_name(c
->bs
));
2201 if ((c
->perm
& new_shared_perm
) != c
->perm
) {
2202 char *user
= bdrv_child_user_desc(c
);
2203 char *perm_names
= bdrv_perm_names(c
->perm
& ~new_shared_perm
);
2205 if (tighten_restrictions
) {
2206 *tighten_restrictions
= true;
2209 error_setg(errp
, "Conflicts with use by %s as '%s', which uses "
2211 user
, c
->name
, perm_names
, bdrv_get_node_name(c
->bs
));
2217 cumulative_perms
|= c
->perm
;
2218 cumulative_shared_perms
&= c
->shared_perm
;
2221 return bdrv_check_perm(bs
, q
, cumulative_perms
, cumulative_shared_perms
,
2222 ignore_children
, tighten_restrictions
, errp
);
2225 /* Needs to be followed by a call to either bdrv_child_set_perm() or
2226 * bdrv_child_abort_perm_update(). */
2227 static int bdrv_child_check_perm(BdrvChild
*c
, BlockReopenQueue
*q
,
2228 uint64_t perm
, uint64_t shared
,
2229 GSList
*ignore_children
,
2230 bool *tighten_restrictions
, Error
**errp
)
2234 ignore_children
= g_slist_prepend(g_slist_copy(ignore_children
), c
);
2235 ret
= bdrv_check_update_perm(c
->bs
, q
, perm
, shared
, ignore_children
,
2236 tighten_restrictions
, errp
);
2237 g_slist_free(ignore_children
);
2243 if (!c
->has_backup_perm
) {
2244 c
->has_backup_perm
= true;
2245 c
->backup_perm
= c
->perm
;
2246 c
->backup_shared_perm
= c
->shared_perm
;
2249 * Note: it's OK if c->has_backup_perm was already set, as we can find the
2250 * same child twice during check_perm procedure
2254 c
->shared_perm
= shared
;
2259 static void bdrv_child_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
)
2261 uint64_t cumulative_perms
, cumulative_shared_perms
;
2263 c
->has_backup_perm
= false;
2266 c
->shared_perm
= shared
;
2268 bdrv_get_cumulative_perm(c
->bs
, &cumulative_perms
,
2269 &cumulative_shared_perms
);
2270 bdrv_set_perm(c
->bs
, cumulative_perms
, cumulative_shared_perms
);
2273 static void bdrv_child_abort_perm_update(BdrvChild
*c
)
2275 if (c
->has_backup_perm
) {
2276 c
->perm
= c
->backup_perm
;
2277 c
->shared_perm
= c
->backup_shared_perm
;
2278 c
->has_backup_perm
= false;
2281 bdrv_abort_perm_update(c
->bs
);
2284 int bdrv_child_try_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
,
2287 Error
*local_err
= NULL
;
2289 bool tighten_restrictions
;
2291 ret
= bdrv_child_check_perm(c
, NULL
, perm
, shared
, NULL
,
2292 &tighten_restrictions
, &local_err
);
2294 bdrv_child_abort_perm_update(c
);
2295 if (tighten_restrictions
) {
2296 error_propagate(errp
, local_err
);
2299 * Our caller may intend to only loosen restrictions and
2300 * does not expect this function to fail. Errors are not
2301 * fatal in such a case, so we can just hide them from our
2304 error_free(local_err
);
2310 bdrv_child_set_perm(c
, perm
, shared
);
2315 int bdrv_child_refresh_perms(BlockDriverState
*bs
, BdrvChild
*c
, Error
**errp
)
2317 uint64_t parent_perms
, parent_shared
;
2318 uint64_t perms
, shared
;
2320 bdrv_get_cumulative_perm(bs
, &parent_perms
, &parent_shared
);
2321 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, NULL
, parent_perms
, parent_shared
,
2324 return bdrv_child_try_set_perm(c
, perms
, shared
, errp
);
2327 void bdrv_filter_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2328 const BdrvChildRole
*role
,
2329 BlockReopenQueue
*reopen_queue
,
2330 uint64_t perm
, uint64_t shared
,
2331 uint64_t *nperm
, uint64_t *nshared
)
2333 *nperm
= perm
& DEFAULT_PERM_PASSTHROUGH
;
2334 *nshared
= (shared
& DEFAULT_PERM_PASSTHROUGH
) | DEFAULT_PERM_UNCHANGED
;
2337 void bdrv_format_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2338 const BdrvChildRole
*role
,
2339 BlockReopenQueue
*reopen_queue
,
2340 uint64_t perm
, uint64_t shared
,
2341 uint64_t *nperm
, uint64_t *nshared
)
2343 bool backing
= (role
== &child_backing
);
2344 assert(role
== &child_backing
|| role
== &child_file
);
2347 int flags
= bdrv_reopen_get_flags(reopen_queue
, bs
);
2349 /* Apart from the modifications below, the same permissions are
2350 * forwarded and left alone as for filters */
2351 bdrv_filter_default_perms(bs
, c
, role
, reopen_queue
, perm
, shared
,
2354 /* Format drivers may touch metadata even if the guest doesn't write */
2355 if (bdrv_is_writable_after_reopen(bs
, reopen_queue
)) {
2356 perm
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2359 /* bs->file always needs to be consistent because of the metadata. We
2360 * can never allow other users to resize or write to it. */
2361 if (!(flags
& BDRV_O_NO_IO
)) {
2362 perm
|= BLK_PERM_CONSISTENT_READ
;
2364 shared
&= ~(BLK_PERM_WRITE
| BLK_PERM_RESIZE
);
2366 /* We want consistent read from backing files if the parent needs it.
2367 * No other operations are performed on backing files. */
2368 perm
&= BLK_PERM_CONSISTENT_READ
;
2370 /* If the parent can deal with changing data, we're okay with a
2371 * writable and resizable backing file. */
2372 /* TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? */
2373 if (shared
& BLK_PERM_WRITE
) {
2374 shared
= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2379 shared
|= BLK_PERM_CONSISTENT_READ
| BLK_PERM_GRAPH_MOD
|
2380 BLK_PERM_WRITE_UNCHANGED
;
2383 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
2384 shared
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2391 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm
)
2393 static const uint64_t permissions
[] = {
2394 [BLOCK_PERMISSION_CONSISTENT_READ
] = BLK_PERM_CONSISTENT_READ
,
2395 [BLOCK_PERMISSION_WRITE
] = BLK_PERM_WRITE
,
2396 [BLOCK_PERMISSION_WRITE_UNCHANGED
] = BLK_PERM_WRITE_UNCHANGED
,
2397 [BLOCK_PERMISSION_RESIZE
] = BLK_PERM_RESIZE
,
2398 [BLOCK_PERMISSION_GRAPH_MOD
] = BLK_PERM_GRAPH_MOD
,
2401 QEMU_BUILD_BUG_ON(ARRAY_SIZE(permissions
) != BLOCK_PERMISSION__MAX
);
2402 QEMU_BUILD_BUG_ON(1UL << ARRAY_SIZE(permissions
) != BLK_PERM_ALL
+ 1);
2404 assert(qapi_perm
< BLOCK_PERMISSION__MAX
);
2406 return permissions
[qapi_perm
];
2409 static void bdrv_replace_child_noperm(BdrvChild
*child
,
2410 BlockDriverState
*new_bs
)
2412 BlockDriverState
*old_bs
= child
->bs
;
2413 int new_bs_quiesce_counter
;
2416 assert(!child
->frozen
);
2418 if (old_bs
&& new_bs
) {
2419 assert(bdrv_get_aio_context(old_bs
) == bdrv_get_aio_context(new_bs
));
2422 new_bs_quiesce_counter
= (new_bs ? new_bs
->quiesce_counter
: 0);
2423 drain_saldo
= new_bs_quiesce_counter
- child
->parent_quiesce_counter
;
2426 * If the new child node is drained but the old one was not, flush
2427 * all outstanding requests to the old child node.
2429 while (drain_saldo
> 0 && child
->role
->drained_begin
) {
2430 bdrv_parent_drained_begin_single(child
, true);
2435 /* Detach first so that the recursive drain sections coming from @child
2436 * are already gone and we only end the drain sections that came from
2438 if (child
->role
->detach
) {
2439 child
->role
->detach(child
);
2441 QLIST_REMOVE(child
, next_parent
);
2447 QLIST_INSERT_HEAD(&new_bs
->parents
, child
, next_parent
);
2450 * Detaching the old node may have led to the new node's
2451 * quiesce_counter having been decreased. Not a problem, we
2452 * just need to recognize this here and then invoke
2453 * drained_end appropriately more often.
2455 assert(new_bs
->quiesce_counter
<= new_bs_quiesce_counter
);
2456 drain_saldo
+= new_bs
->quiesce_counter
- new_bs_quiesce_counter
;
2458 /* Attach only after starting new drained sections, so that recursive
2459 * drain sections coming from @child don't get an extra .drained_begin
2461 if (child
->role
->attach
) {
2462 child
->role
->attach(child
);
2467 * If the old child node was drained but the new one is not, allow
2468 * requests to come in only after the new node has been attached.
2470 while (drain_saldo
< 0 && child
->role
->drained_end
) {
2471 bdrv_parent_drained_end_single(child
);
2477 * Updates @child to change its reference to point to @new_bs, including
2478 * checking and applying the necessary permisson updates both to the old node
2481 * NULL is passed as @new_bs for removing the reference before freeing @child.
2483 * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this
2484 * function uses bdrv_set_perm() to update the permissions according to the new
2485 * reference that @new_bs gets.
2487 static void bdrv_replace_child(BdrvChild
*child
, BlockDriverState
*new_bs
)
2489 BlockDriverState
*old_bs
= child
->bs
;
2490 uint64_t perm
, shared_perm
;
2492 bdrv_replace_child_noperm(child
, new_bs
);
2495 * Start with the new node's permissions. If @new_bs is a (direct
2496 * or indirect) child of @old_bs, we must complete the permission
2497 * update on @new_bs before we loosen the restrictions on @old_bs.
2498 * Otherwise, bdrv_check_perm() on @old_bs would re-initiate
2499 * updating the permissions of @new_bs, and thus not purely loosen
2503 bdrv_get_cumulative_perm(new_bs
, &perm
, &shared_perm
);
2504 bdrv_set_perm(new_bs
, perm
, shared_perm
);
2508 /* Update permissions for old node. This is guaranteed to succeed
2509 * because we're just taking a parent away, so we're loosening
2511 bool tighten_restrictions
;
2514 bdrv_get_cumulative_perm(old_bs
, &perm
, &shared_perm
);
2515 ret
= bdrv_check_perm(old_bs
, NULL
, perm
, shared_perm
, NULL
,
2516 &tighten_restrictions
, NULL
);
2517 assert(tighten_restrictions
== false);
2519 /* We only tried to loosen restrictions, so errors are not fatal */
2520 bdrv_abort_perm_update(old_bs
);
2522 bdrv_set_perm(old_bs
, perm
, shared_perm
);
2525 /* When the parent requiring a non-default AioContext is removed, the
2526 * node moves back to the main AioContext */
2527 bdrv_try_set_aio_context(old_bs
, qemu_get_aio_context(), NULL
);
2532 * This function steals the reference to child_bs from the caller.
2533 * That reference is later dropped by bdrv_root_unref_child().
2535 * On failure NULL is returned, errp is set and the reference to
2536 * child_bs is also dropped.
2538 * The caller must hold the AioContext lock @child_bs, but not that of @ctx
2539 * (unless @child_bs is already in @ctx).
2541 BdrvChild
*bdrv_root_attach_child(BlockDriverState
*child_bs
,
2542 const char *child_name
,
2543 const BdrvChildRole
*child_role
,
2545 uint64_t perm
, uint64_t shared_perm
,
2546 void *opaque
, Error
**errp
)
2549 Error
*local_err
= NULL
;
2552 ret
= bdrv_check_update_perm(child_bs
, NULL
, perm
, shared_perm
, NULL
, NULL
,
2555 bdrv_abort_perm_update(child_bs
);
2556 bdrv_unref(child_bs
);
2560 child
= g_new(BdrvChild
, 1);
2561 *child
= (BdrvChild
) {
2563 .name
= g_strdup(child_name
),
2566 .shared_perm
= shared_perm
,
2570 /* If the AioContexts don't match, first try to move the subtree of
2571 * child_bs into the AioContext of the new parent. If this doesn't work,
2572 * try moving the parent into the AioContext of child_bs instead. */
2573 if (bdrv_get_aio_context(child_bs
) != ctx
) {
2574 ret
= bdrv_try_set_aio_context(child_bs
, ctx
, &local_err
);
2575 if (ret
< 0 && child_role
->can_set_aio_ctx
) {
2576 GSList
*ignore
= g_slist_prepend(NULL
, child
);
2577 ctx
= bdrv_get_aio_context(child_bs
);
2578 if (child_role
->can_set_aio_ctx(child
, ctx
, &ignore
, NULL
)) {
2579 error_free(local_err
);
2581 g_slist_free(ignore
);
2582 ignore
= g_slist_prepend(NULL
, child
);
2583 child_role
->set_aio_ctx(child
, ctx
, &ignore
);
2585 g_slist_free(ignore
);
2588 error_propagate(errp
, local_err
);
2590 bdrv_abort_perm_update(child_bs
);
2595 /* This performs the matching bdrv_set_perm() for the above check. */
2596 bdrv_replace_child(child
, child_bs
);
2602 * This function transfers the reference to child_bs from the caller
2603 * to parent_bs. That reference is later dropped by parent_bs on
2604 * bdrv_close() or if someone calls bdrv_unref_child().
2606 * On failure NULL is returned, errp is set and the reference to
2607 * child_bs is also dropped.
2609 * If @parent_bs and @child_bs are in different AioContexts, the caller must
2610 * hold the AioContext lock for @child_bs, but not for @parent_bs.
2612 BdrvChild
*bdrv_attach_child(BlockDriverState
*parent_bs
,
2613 BlockDriverState
*child_bs
,
2614 const char *child_name
,
2615 const BdrvChildRole
*child_role
,
2619 uint64_t perm
, shared_perm
;
2621 bdrv_get_cumulative_perm(parent_bs
, &perm
, &shared_perm
);
2623 assert(parent_bs
->drv
);
2624 bdrv_child_perm(parent_bs
, child_bs
, NULL
, child_role
, NULL
,
2625 perm
, shared_perm
, &perm
, &shared_perm
);
2627 child
= bdrv_root_attach_child(child_bs
, child_name
, child_role
,
2628 bdrv_get_aio_context(parent_bs
),
2629 perm
, shared_perm
, parent_bs
, errp
);
2630 if (child
== NULL
) {
2634 QLIST_INSERT_HEAD(&parent_bs
->children
, child
, next
);
2638 static void bdrv_detach_child(BdrvChild
*child
)
2640 QLIST_SAFE_REMOVE(child
, next
);
2642 bdrv_replace_child(child
, NULL
);
2644 g_free(child
->name
);
2648 void bdrv_root_unref_child(BdrvChild
*child
)
2650 BlockDriverState
*child_bs
;
2652 child_bs
= child
->bs
;
2653 bdrv_detach_child(child
);
2654 bdrv_unref(child_bs
);
2658 * Clear all inherits_from pointers from children and grandchildren of
2659 * @root that point to @root, where necessary.
2661 static void bdrv_unset_inherits_from(BlockDriverState
*root
, BdrvChild
*child
)
2665 if (child
->bs
->inherits_from
== root
) {
2667 * Remove inherits_from only when the last reference between root and
2668 * child->bs goes away.
2670 QLIST_FOREACH(c
, &root
->children
, next
) {
2671 if (c
!= child
&& c
->bs
== child
->bs
) {
2676 child
->bs
->inherits_from
= NULL
;
2680 QLIST_FOREACH(c
, &child
->bs
->children
, next
) {
2681 bdrv_unset_inherits_from(root
, c
);
2685 void bdrv_unref_child(BlockDriverState
*parent
, BdrvChild
*child
)
2687 if (child
== NULL
) {
2691 bdrv_unset_inherits_from(parent
, child
);
2692 bdrv_root_unref_child(child
);
2696 static void bdrv_parent_cb_change_media(BlockDriverState
*bs
, bool load
)
2699 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
2700 if (c
->role
->change_media
) {
2701 c
->role
->change_media(c
, load
);
2706 /* Return true if you can reach parent going through child->inherits_from
2707 * recursively. If parent or child are NULL, return false */
2708 static bool bdrv_inherits_from_recursive(BlockDriverState
*child
,
2709 BlockDriverState
*parent
)
2711 while (child
&& child
!= parent
) {
2712 child
= child
->inherits_from
;
2715 return child
!= NULL
;
2719 * Sets the backing file link of a BDS. A new reference is created; callers
2720 * which don't need their own reference any more must call bdrv_unref().
2722 void bdrv_set_backing_hd(BlockDriverState
*bs
, BlockDriverState
*backing_hd
,
2725 bool update_inherits_from
= bdrv_chain_contains(bs
, backing_hd
) &&
2726 bdrv_inherits_from_recursive(backing_hd
, bs
);
2728 if (bdrv_is_backing_chain_frozen(bs
, backing_bs(bs
), errp
)) {
2733 bdrv_ref(backing_hd
);
2737 bdrv_unref_child(bs
, bs
->backing
);
2745 bs
->backing
= bdrv_attach_child(bs
, backing_hd
, "backing", &child_backing
,
2747 /* If backing_hd was already part of bs's backing chain, and
2748 * inherits_from pointed recursively to bs then let's update it to
2749 * point directly to bs (else it will become NULL). */
2750 if (bs
->backing
&& update_inherits_from
) {
2751 backing_hd
->inherits_from
= bs
;
2755 bdrv_refresh_limits(bs
, NULL
);
2759 * Opens the backing file for a BlockDriverState if not yet open
2761 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
2762 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2763 * itself, all options starting with "${bdref_key}." are considered part of the
2766 * TODO Can this be unified with bdrv_open_image()?
2768 int bdrv_open_backing_file(BlockDriverState
*bs
, QDict
*parent_options
,
2769 const char *bdref_key
, Error
**errp
)
2771 char *backing_filename
= NULL
;
2772 char *bdref_key_dot
;
2773 const char *reference
= NULL
;
2775 bool implicit_backing
= false;
2776 BlockDriverState
*backing_hd
;
2778 QDict
*tmp_parent_options
= NULL
;
2779 Error
*local_err
= NULL
;
2781 if (bs
->backing
!= NULL
) {
2785 /* NULL means an empty set of options */
2786 if (parent_options
== NULL
) {
2787 tmp_parent_options
= qdict_new();
2788 parent_options
= tmp_parent_options
;
2791 bs
->open_flags
&= ~BDRV_O_NO_BACKING
;
2793 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
2794 qdict_extract_subqdict(parent_options
, &options
, bdref_key_dot
);
2795 g_free(bdref_key_dot
);
2798 * Caution: while qdict_get_try_str() is fine, getting non-string
2799 * types would require more care. When @parent_options come from
2800 * -blockdev or blockdev_add, its members are typed according to
2801 * the QAPI schema, but when they come from -drive, they're all
2804 reference
= qdict_get_try_str(parent_options
, bdref_key
);
2805 if (reference
|| qdict_haskey(options
, "file.filename")) {
2806 /* keep backing_filename NULL */
2807 } else if (bs
->backing_file
[0] == '\0' && qdict_size(options
) == 0) {
2808 qobject_unref(options
);
2811 if (qdict_size(options
) == 0) {
2812 /* If the user specifies options that do not modify the
2813 * backing file's behavior, we might still consider it the
2814 * implicit backing file. But it's easier this way, and
2815 * just specifying some of the backing BDS's options is
2816 * only possible with -drive anyway (otherwise the QAPI
2817 * schema forces the user to specify everything). */
2818 implicit_backing
= !strcmp(bs
->auto_backing_file
, bs
->backing_file
);
2821 backing_filename
= bdrv_get_full_backing_filename(bs
, &local_err
);
2824 error_propagate(errp
, local_err
);
2825 qobject_unref(options
);
2830 if (!bs
->drv
|| !bs
->drv
->supports_backing
) {
2832 error_setg(errp
, "Driver doesn't support backing files");
2833 qobject_unref(options
);
2838 bs
->backing_format
[0] != '\0' && !qdict_haskey(options
, "driver")) {
2839 qdict_put_str(options
, "driver", bs
->backing_format
);
2842 backing_hd
= bdrv_open_inherit(backing_filename
, reference
, options
, 0, bs
,
2843 &child_backing
, errp
);
2845 bs
->open_flags
|= BDRV_O_NO_BACKING
;
2846 error_prepend(errp
, "Could not open backing file: ");
2851 if (implicit_backing
) {
2852 bdrv_refresh_filename(backing_hd
);
2853 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
2854 backing_hd
->filename
);
2857 /* Hook up the backing file link; drop our reference, bs owns the
2858 * backing_hd reference now */
2859 bdrv_set_backing_hd(bs
, backing_hd
, &local_err
);
2860 bdrv_unref(backing_hd
);
2862 error_propagate(errp
, local_err
);
2867 qdict_del(parent_options
, bdref_key
);
2870 g_free(backing_filename
);
2871 qobject_unref(tmp_parent_options
);
2875 static BlockDriverState
*
2876 bdrv_open_child_bs(const char *filename
, QDict
*options
, const char *bdref_key
,
2877 BlockDriverState
*parent
, const BdrvChildRole
*child_role
,
2878 bool allow_none
, Error
**errp
)
2880 BlockDriverState
*bs
= NULL
;
2881 QDict
*image_options
;
2882 char *bdref_key_dot
;
2883 const char *reference
;
2885 assert(child_role
!= NULL
);
2887 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
2888 qdict_extract_subqdict(options
, &image_options
, bdref_key_dot
);
2889 g_free(bdref_key_dot
);
2892 * Caution: while qdict_get_try_str() is fine, getting non-string
2893 * types would require more care. When @options come from
2894 * -blockdev or blockdev_add, its members are typed according to
2895 * the QAPI schema, but when they come from -drive, they're all
2898 reference
= qdict_get_try_str(options
, bdref_key
);
2899 if (!filename
&& !reference
&& !qdict_size(image_options
)) {
2901 error_setg(errp
, "A block device must be specified for \"%s\"",
2904 qobject_unref(image_options
);
2908 bs
= bdrv_open_inherit(filename
, reference
, image_options
, 0,
2909 parent
, child_role
, errp
);
2915 qdict_del(options
, bdref_key
);
2920 * Opens a disk image whose options are given as BlockdevRef in another block
2923 * If allow_none is true, no image will be opened if filename is false and no
2924 * BlockdevRef is given. NULL will be returned, but errp remains unset.
2926 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
2927 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2928 * itself, all options starting with "${bdref_key}." are considered part of the
2931 * The BlockdevRef will be removed from the options QDict.
2933 BdrvChild
*bdrv_open_child(const char *filename
,
2934 QDict
*options
, const char *bdref_key
,
2935 BlockDriverState
*parent
,
2936 const BdrvChildRole
*child_role
,
2937 bool allow_none
, Error
**errp
)
2939 BlockDriverState
*bs
;
2941 bs
= bdrv_open_child_bs(filename
, options
, bdref_key
, parent
, child_role
,
2947 return bdrv_attach_child(parent
, bs
, bdref_key
, child_role
, errp
);
2950 /* TODO Future callers may need to specify parent/child_role in order for
2951 * option inheritance to work. Existing callers use it for the root node. */
2952 BlockDriverState
*bdrv_open_blockdev_ref(BlockdevRef
*ref
, Error
**errp
)
2954 BlockDriverState
*bs
= NULL
;
2955 Error
*local_err
= NULL
;
2956 QObject
*obj
= NULL
;
2957 QDict
*qdict
= NULL
;
2958 const char *reference
= NULL
;
2961 if (ref
->type
== QTYPE_QSTRING
) {
2962 reference
= ref
->u
.reference
;
2964 BlockdevOptions
*options
= &ref
->u
.definition
;
2965 assert(ref
->type
== QTYPE_QDICT
);
2967 v
= qobject_output_visitor_new(&obj
);
2968 visit_type_BlockdevOptions(v
, NULL
, &options
, &local_err
);
2970 error_propagate(errp
, local_err
);
2973 visit_complete(v
, &obj
);
2975 qdict
= qobject_to(QDict
, obj
);
2976 qdict_flatten(qdict
);
2978 /* bdrv_open_inherit() defaults to the values in bdrv_flags (for
2979 * compatibility with other callers) rather than what we want as the
2980 * real defaults. Apply the defaults here instead. */
2981 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_DIRECT
, "off");
2982 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_NO_FLUSH
, "off");
2983 qdict_set_default_str(qdict
, BDRV_OPT_READ_ONLY
, "off");
2984 qdict_set_default_str(qdict
, BDRV_OPT_AUTO_READ_ONLY
, "off");
2988 bs
= bdrv_open_inherit(NULL
, reference
, qdict
, 0, NULL
, NULL
, errp
);
2997 static BlockDriverState
*bdrv_append_temp_snapshot(BlockDriverState
*bs
,
2999 QDict
*snapshot_options
,
3002 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
3003 char *tmp_filename
= g_malloc0(PATH_MAX
+ 1);
3005 QemuOpts
*opts
= NULL
;
3006 BlockDriverState
*bs_snapshot
= NULL
;
3007 Error
*local_err
= NULL
;
3010 /* if snapshot, we create a temporary backing file and open it
3011 instead of opening 'filename' directly */
3013 /* Get the required size from the image */
3014 total_size
= bdrv_getlength(bs
);
3015 if (total_size
< 0) {
3016 error_setg_errno(errp
, -total_size
, "Could not get image size");
3020 /* Create the temporary image */
3021 ret
= get_tmp_filename(tmp_filename
, PATH_MAX
+ 1);
3023 error_setg_errno(errp
, -ret
, "Could not get temporary filename");
3027 opts
= qemu_opts_create(bdrv_qcow2
.create_opts
, NULL
, 0,
3029 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, total_size
, &error_abort
);
3030 ret
= bdrv_create(&bdrv_qcow2
, tmp_filename
, opts
, errp
);
3031 qemu_opts_del(opts
);
3033 error_prepend(errp
, "Could not create temporary overlay '%s': ",
3038 /* Prepare options QDict for the temporary file */
3039 qdict_put_str(snapshot_options
, "file.driver", "file");
3040 qdict_put_str(snapshot_options
, "file.filename", tmp_filename
);
3041 qdict_put_str(snapshot_options
, "driver", "qcow2");
3043 bs_snapshot
= bdrv_open(NULL
, NULL
, snapshot_options
, flags
, errp
);
3044 snapshot_options
= NULL
;
3049 /* bdrv_append() consumes a strong reference to bs_snapshot
3050 * (i.e. it will call bdrv_unref() on it) even on error, so in
3051 * order to be able to return one, we have to increase
3052 * bs_snapshot's refcount here */
3053 bdrv_ref(bs_snapshot
);
3054 bdrv_append(bs_snapshot
, bs
, &local_err
);
3056 error_propagate(errp
, local_err
);
3062 qobject_unref(snapshot_options
);
3063 g_free(tmp_filename
);
3068 * Opens a disk image (raw, qcow2, vmdk, ...)
3070 * options is a QDict of options to pass to the block drivers, or NULL for an
3071 * empty set of options. The reference to the QDict belongs to the block layer
3072 * after the call (even on failure), so if the caller intends to reuse the
3073 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
3075 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
3076 * If it is not NULL, the referenced BDS will be reused.
3078 * The reference parameter may be used to specify an existing block device which
3079 * should be opened. If specified, neither options nor a filename may be given,
3080 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
3082 static BlockDriverState
*bdrv_open_inherit(const char *filename
,
3083 const char *reference
,
3084 QDict
*options
, int flags
,
3085 BlockDriverState
*parent
,
3086 const BdrvChildRole
*child_role
,
3090 BlockBackend
*file
= NULL
;
3091 BlockDriverState
*bs
;
3092 BlockDriver
*drv
= NULL
;
3094 const char *drvname
;
3095 const char *backing
;
3096 Error
*local_err
= NULL
;
3097 QDict
*snapshot_options
= NULL
;
3098 int snapshot_flags
= 0;
3100 assert(!child_role
|| !flags
);
3101 assert(!child_role
== !parent
);
3104 bool options_non_empty
= options ?
qdict_size(options
) : false;
3105 qobject_unref(options
);
3107 if (filename
|| options_non_empty
) {
3108 error_setg(errp
, "Cannot reference an existing block device with "
3109 "additional options or a new filename");
3113 bs
= bdrv_lookup_bs(reference
, reference
, errp
);
3124 /* NULL means an empty set of options */
3125 if (options
== NULL
) {
3126 options
= qdict_new();
3129 /* json: syntax counts as explicit options, as if in the QDict */
3130 parse_json_protocol(options
, &filename
, &local_err
);
3135 bs
->explicit_options
= qdict_clone_shallow(options
);
3138 bs
->inherits_from
= parent
;
3139 child_role
->inherit_options(&flags
, options
,
3140 parent
->open_flags
, parent
->options
);
3143 ret
= bdrv_fill_options(&options
, filename
, &flags
, &local_err
);
3149 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
3150 * Caution: getting a boolean member of @options requires care.
3151 * When @options come from -blockdev or blockdev_add, members are
3152 * typed according to the QAPI schema, but when they come from
3153 * -drive, they're all QString.
3155 if (g_strcmp0(qdict_get_try_str(options
, BDRV_OPT_READ_ONLY
), "on") &&
3156 !qdict_get_try_bool(options
, BDRV_OPT_READ_ONLY
, false)) {
3157 flags
|= (BDRV_O_RDWR
| BDRV_O_ALLOW_RDWR
);
3159 flags
&= ~BDRV_O_RDWR
;
3162 if (flags
& BDRV_O_SNAPSHOT
) {
3163 snapshot_options
= qdict_new();
3164 bdrv_temp_snapshot_options(&snapshot_flags
, snapshot_options
,
3166 /* Let bdrv_backing_options() override "read-only" */
3167 qdict_del(options
, BDRV_OPT_READ_ONLY
);
3168 bdrv_backing_options(&flags
, options
, flags
, options
);
3171 bs
->open_flags
= flags
;
3172 bs
->options
= options
;
3173 options
= qdict_clone_shallow(options
);
3175 /* Find the right image format driver */
3176 /* See cautionary note on accessing @options above */
3177 drvname
= qdict_get_try_str(options
, "driver");
3179 drv
= bdrv_find_format(drvname
);
3181 error_setg(errp
, "Unknown driver: '%s'", drvname
);
3186 assert(drvname
|| !(flags
& BDRV_O_PROTOCOL
));
3188 /* See cautionary note on accessing @options above */
3189 backing
= qdict_get_try_str(options
, "backing");
3190 if (qobject_to(QNull
, qdict_get(options
, "backing")) != NULL
||
3191 (backing
&& *backing
== '\0'))
3194 warn_report("Use of \"backing\": \"\" is deprecated; "
3195 "use \"backing\": null instead");
3197 flags
|= BDRV_O_NO_BACKING
;
3198 qdict_del(bs
->explicit_options
, "backing");
3199 qdict_del(bs
->options
, "backing");
3200 qdict_del(options
, "backing");
3203 /* Open image file without format layer. This BlockBackend is only used for
3204 * probing, the block drivers will do their own bdrv_open_child() for the
3205 * same BDS, which is why we put the node name back into options. */
3206 if ((flags
& BDRV_O_PROTOCOL
) == 0) {
3207 BlockDriverState
*file_bs
;
3209 file_bs
= bdrv_open_child_bs(filename
, options
, "file", bs
,
3210 &child_file
, true, &local_err
);
3214 if (file_bs
!= NULL
) {
3215 /* Not requesting BLK_PERM_CONSISTENT_READ because we're only
3216 * looking at the header to guess the image format. This works even
3217 * in cases where a guest would not see a consistent state. */
3218 file
= blk_new(bdrv_get_aio_context(file_bs
), 0, BLK_PERM_ALL
);
3219 blk_insert_bs(file
, file_bs
, &local_err
);
3220 bdrv_unref(file_bs
);
3225 qdict_put_str(options
, "file", bdrv_get_node_name(file_bs
));
3229 /* Image format probing */
3232 ret
= find_image_format(file
, filename
, &drv
, &local_err
);
3237 * This option update would logically belong in bdrv_fill_options(),
3238 * but we first need to open bs->file for the probing to work, while
3239 * opening bs->file already requires the (mostly) final set of options
3240 * so that cache mode etc. can be inherited.
3242 * Adding the driver later is somewhat ugly, but it's not an option
3243 * that would ever be inherited, so it's correct. We just need to make
3244 * sure to update both bs->options (which has the full effective
3245 * options for bs) and options (which has file.* already removed).
3247 qdict_put_str(bs
->options
, "driver", drv
->format_name
);
3248 qdict_put_str(options
, "driver", drv
->format_name
);
3250 error_setg(errp
, "Must specify either driver or file");
3254 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
3255 assert(!!(flags
& BDRV_O_PROTOCOL
) == !!drv
->bdrv_file_open
);
3256 /* file must be NULL if a protocol BDS is about to be created
3257 * (the inverse results in an error message from bdrv_open_common()) */
3258 assert(!(flags
& BDRV_O_PROTOCOL
) || !file
);
3260 /* Open the image */
3261 ret
= bdrv_open_common(bs
, file
, options
, &local_err
);
3271 /* If there is a backing file, use it */
3272 if ((flags
& BDRV_O_NO_BACKING
) == 0) {
3273 ret
= bdrv_open_backing_file(bs
, options
, "backing", &local_err
);
3275 goto close_and_fail
;
3279 /* Remove all children options and references
3280 * from bs->options and bs->explicit_options */
3281 QLIST_FOREACH(child
, &bs
->children
, next
) {
3282 char *child_key_dot
;
3283 child_key_dot
= g_strdup_printf("%s.", child
->name
);
3284 qdict_extract_subqdict(bs
->explicit_options
, NULL
, child_key_dot
);
3285 qdict_extract_subqdict(bs
->options
, NULL
, child_key_dot
);
3286 qdict_del(bs
->explicit_options
, child
->name
);
3287 qdict_del(bs
->options
, child
->name
);
3288 g_free(child_key_dot
);
3291 /* Check if any unknown options were used */
3292 if (qdict_size(options
) != 0) {
3293 const QDictEntry
*entry
= qdict_first(options
);
3294 if (flags
& BDRV_O_PROTOCOL
) {
3295 error_setg(errp
, "Block protocol '%s' doesn't support the option "
3296 "'%s'", drv
->format_name
, entry
->key
);
3299 "Block format '%s' does not support the option '%s'",
3300 drv
->format_name
, entry
->key
);
3303 goto close_and_fail
;
3306 bdrv_parent_cb_change_media(bs
, true);
3308 qobject_unref(options
);
3311 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
3312 * temporary snapshot afterwards. */
3313 if (snapshot_flags
) {
3314 BlockDriverState
*snapshot_bs
;
3315 snapshot_bs
= bdrv_append_temp_snapshot(bs
, snapshot_flags
,
3316 snapshot_options
, &local_err
);
3317 snapshot_options
= NULL
;
3319 goto close_and_fail
;
3321 /* We are not going to return bs but the overlay on top of it
3322 * (snapshot_bs); thus, we have to drop the strong reference to bs
3323 * (which we obtained by calling bdrv_new()). bs will not be deleted,
3324 * though, because the overlay still has a reference to it. */
3333 qobject_unref(snapshot_options
);
3334 qobject_unref(bs
->explicit_options
);
3335 qobject_unref(bs
->options
);
3336 qobject_unref(options
);
3338 bs
->explicit_options
= NULL
;
3340 error_propagate(errp
, local_err
);
3345 qobject_unref(snapshot_options
);
3346 qobject_unref(options
);
3347 error_propagate(errp
, local_err
);
3351 BlockDriverState
*bdrv_open(const char *filename
, const char *reference
,
3352 QDict
*options
, int flags
, Error
**errp
)
3354 return bdrv_open_inherit(filename
, reference
, options
, flags
, NULL
,
3358 /* Return true if the NULL-terminated @list contains @str */
3359 static bool is_str_in_list(const char *str
, const char *const *list
)
3363 for (i
= 0; list
[i
] != NULL
; i
++) {
3364 if (!strcmp(str
, list
[i
])) {
3373 * Check that every option set in @bs->options is also set in
3376 * Options listed in the common_options list and in
3377 * @bs->drv->mutable_opts are skipped.
3379 * Return 0 on success, otherwise return -EINVAL and set @errp.
3381 static int bdrv_reset_options_allowed(BlockDriverState
*bs
,
3382 const QDict
*new_opts
, Error
**errp
)
3384 const QDictEntry
*e
;
3385 /* These options are common to all block drivers and are handled
3386 * in bdrv_reopen_prepare() so they can be left out of @new_opts */
3387 const char *const common_options
[] = {
3388 "node-name", "discard", "cache.direct", "cache.no-flush",
3389 "read-only", "auto-read-only", "detect-zeroes", NULL
3392 for (e
= qdict_first(bs
->options
); e
; e
= qdict_next(bs
->options
, e
)) {
3393 if (!qdict_haskey(new_opts
, e
->key
) &&
3394 !is_str_in_list(e
->key
, common_options
) &&
3395 !is_str_in_list(e
->key
, bs
->drv
->mutable_opts
)) {
3396 error_setg(errp
, "Option '%s' cannot be reset "
3397 "to its default value", e
->key
);
3406 * Returns true if @child can be reached recursively from @bs
3408 static bool bdrv_recurse_has_child(BlockDriverState
*bs
,
3409 BlockDriverState
*child
)
3417 QLIST_FOREACH(c
, &bs
->children
, next
) {
3418 if (bdrv_recurse_has_child(c
->bs
, child
)) {
3427 * Adds a BlockDriverState to a simple queue for an atomic, transactional
3428 * reopen of multiple devices.
3430 * bs_queue can either be an existing BlockReopenQueue that has had QTAILQ_INIT
3431 * already performed, or alternatively may be NULL a new BlockReopenQueue will
3432 * be created and initialized. This newly created BlockReopenQueue should be
3433 * passed back in for subsequent calls that are intended to be of the same
3436 * bs is the BlockDriverState to add to the reopen queue.
3438 * options contains the changed options for the associated bs
3439 * (the BlockReopenQueue takes ownership)
3441 * flags contains the open flags for the associated bs
3443 * returns a pointer to bs_queue, which is either the newly allocated
3444 * bs_queue, or the existing bs_queue being used.
3446 * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple().
3448 static BlockReopenQueue
*bdrv_reopen_queue_child(BlockReopenQueue
*bs_queue
,
3449 BlockDriverState
*bs
,
3451 const BdrvChildRole
*role
,
3452 QDict
*parent_options
,
3458 BlockReopenQueueEntry
*bs_entry
;
3460 QDict
*old_options
, *explicit_options
, *options_copy
;
3464 /* Make sure that the caller remembered to use a drained section. This is
3465 * important to avoid graph changes between the recursive queuing here and
3466 * bdrv_reopen_multiple(). */
3467 assert(bs
->quiesce_counter
> 0);
3469 if (bs_queue
== NULL
) {
3470 bs_queue
= g_new0(BlockReopenQueue
, 1);
3471 QTAILQ_INIT(bs_queue
);
3475 options
= qdict_new();
3478 /* Check if this BlockDriverState is already in the queue */
3479 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
3480 if (bs
== bs_entry
->state
.bs
) {
3486 * Precedence of options:
3487 * 1. Explicitly passed in options (highest)
3488 * 2. Retained from explicitly set options of bs
3489 * 3. Inherited from parent node
3490 * 4. Retained from effective options of bs
3493 /* Old explicitly set values (don't overwrite by inherited value) */
3494 if (bs_entry
|| keep_old_opts
) {
3495 old_options
= qdict_clone_shallow(bs_entry ?
3496 bs_entry
->state
.explicit_options
:
3497 bs
->explicit_options
);
3498 bdrv_join_options(bs
, options
, old_options
);
3499 qobject_unref(old_options
);
3502 explicit_options
= qdict_clone_shallow(options
);
3504 /* Inherit from parent node */
3505 if (parent_options
) {
3507 role
->inherit_options(&flags
, options
, parent_flags
, parent_options
);
3509 flags
= bdrv_get_flags(bs
);
3512 if (keep_old_opts
) {
3513 /* Old values are used for options that aren't set yet */
3514 old_options
= qdict_clone_shallow(bs
->options
);
3515 bdrv_join_options(bs
, options
, old_options
);
3516 qobject_unref(old_options
);
3519 /* We have the final set of options so let's update the flags */
3520 options_copy
= qdict_clone_shallow(options
);
3521 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
3522 qemu_opts_absorb_qdict(opts
, options_copy
, NULL
);
3523 update_flags_from_options(&flags
, opts
);
3524 qemu_opts_del(opts
);
3525 qobject_unref(options_copy
);
3527 /* bdrv_open_inherit() sets and clears some additional flags internally */
3528 flags
&= ~BDRV_O_PROTOCOL
;
3529 if (flags
& BDRV_O_RDWR
) {
3530 flags
|= BDRV_O_ALLOW_RDWR
;
3534 bs_entry
= g_new0(BlockReopenQueueEntry
, 1);
3535 QTAILQ_INSERT_TAIL(bs_queue
, bs_entry
, entry
);
3537 qobject_unref(bs_entry
->state
.options
);
3538 qobject_unref(bs_entry
->state
.explicit_options
);
3541 bs_entry
->state
.bs
= bs
;
3542 bs_entry
->state
.options
= options
;
3543 bs_entry
->state
.explicit_options
= explicit_options
;
3544 bs_entry
->state
.flags
= flags
;
3546 /* This needs to be overwritten in bdrv_reopen_prepare() */
3547 bs_entry
->state
.perm
= UINT64_MAX
;
3548 bs_entry
->state
.shared_perm
= 0;
3551 * If keep_old_opts is false then it means that unspecified
3552 * options must be reset to their original value. We don't allow