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 assert(bdrv
->format_name
);
367 QLIST_INSERT_HEAD(&bdrv_drivers
, bdrv
, list
);
370 BlockDriverState
*bdrv_new(void)
372 BlockDriverState
*bs
;
375 bs
= g_new0(BlockDriverState
, 1);
376 QLIST_INIT(&bs
->dirty_bitmaps
);
377 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
378 QLIST_INIT(&bs
->op_blockers
[i
]);
380 notifier_with_return_list_init(&bs
->before_write_notifiers
);
381 qemu_co_mutex_init(&bs
->reqs_lock
);
382 qemu_mutex_init(&bs
->dirty_bitmap_mutex
);
384 bs
->aio_context
= qemu_get_aio_context();
386 qemu_co_queue_init(&bs
->flush_queue
);
388 for (i
= 0; i
< bdrv_drain_all_count
; i
++) {
389 bdrv_drained_begin(bs
);
392 QTAILQ_INSERT_TAIL(&all_bdrv_states
, bs
, bs_list
);
397 static BlockDriver
*bdrv_do_find_format(const char *format_name
)
401 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
402 if (!strcmp(drv1
->format_name
, format_name
)) {
410 BlockDriver
*bdrv_find_format(const char *format_name
)
415 drv1
= bdrv_do_find_format(format_name
);
420 /* The driver isn't registered, maybe we need to load a module */
421 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
422 if (!strcmp(block_driver_modules
[i
].format_name
, format_name
)) {
423 block_module_load_one(block_driver_modules
[i
].library_name
);
428 return bdrv_do_find_format(format_name
);
431 static int bdrv_format_is_whitelisted(const char *format_name
, bool read_only
)
433 static const char *whitelist_rw
[] = {
434 CONFIG_BDRV_RW_WHITELIST
436 static const char *whitelist_ro
[] = {
437 CONFIG_BDRV_RO_WHITELIST
441 if (!whitelist_rw
[0] && !whitelist_ro
[0]) {
442 return 1; /* no whitelist, anything goes */
445 for (p
= whitelist_rw
; *p
; p
++) {
446 if (!strcmp(format_name
, *p
)) {
451 for (p
= whitelist_ro
; *p
; p
++) {
452 if (!strcmp(format_name
, *p
)) {
460 int bdrv_is_whitelisted(BlockDriver
*drv
, bool read_only
)
462 return bdrv_format_is_whitelisted(drv
->format_name
, read_only
);
465 bool bdrv_uses_whitelist(void)
467 return use_bdrv_whitelist
;
470 typedef struct CreateCo
{
478 static void coroutine_fn
bdrv_create_co_entry(void *opaque
)
480 Error
*local_err
= NULL
;
483 CreateCo
*cco
= opaque
;
486 ret
= cco
->drv
->bdrv_co_create_opts(cco
->filename
, cco
->opts
, &local_err
);
487 error_propagate(&cco
->err
, local_err
);
491 int bdrv_create(BlockDriver
*drv
, const char* filename
,
492 QemuOpts
*opts
, Error
**errp
)
499 .filename
= g_strdup(filename
),
505 if (!drv
->bdrv_co_create_opts
) {
506 error_setg(errp
, "Driver '%s' does not support image creation", drv
->format_name
);
511 if (qemu_in_coroutine()) {
512 /* Fast-path if already in coroutine context */
513 bdrv_create_co_entry(&cco
);
515 co
= qemu_coroutine_create(bdrv_create_co_entry
, &cco
);
516 qemu_coroutine_enter(co
);
517 while (cco
.ret
== NOT_DONE
) {
518 aio_poll(qemu_get_aio_context(), true);
525 error_propagate(errp
, cco
.err
);
527 error_setg_errno(errp
, -ret
, "Could not create image");
532 g_free(cco
.filename
);
537 * Helper function for bdrv_create_file_fallback(): Resize @blk to at
538 * least the given @minimum_size.
540 * On success, return @blk's actual length.
541 * Otherwise, return -errno.
543 static int64_t create_file_fallback_truncate(BlockBackend
*blk
,
544 int64_t minimum_size
, Error
**errp
)
546 Error
*local_err
= NULL
;
550 ret
= blk_truncate(blk
, minimum_size
, false, PREALLOC_MODE_OFF
, &local_err
);
551 if (ret
< 0 && ret
!= -ENOTSUP
) {
552 error_propagate(errp
, local_err
);
556 size
= blk_getlength(blk
);
558 error_free(local_err
);
559 error_setg_errno(errp
, -size
,
560 "Failed to inquire the new image file's length");
564 if (size
< minimum_size
) {
565 /* Need to grow the image, but we failed to do that */
566 error_propagate(errp
, local_err
);
570 error_free(local_err
);
577 * Helper function for bdrv_create_file_fallback(): Zero the first
578 * sector to remove any potentially pre-existing image header.
580 static int create_file_fallback_zero_first_sector(BlockBackend
*blk
,
581 int64_t current_size
,
584 int64_t bytes_to_clear
;
587 bytes_to_clear
= MIN(current_size
, BDRV_SECTOR_SIZE
);
588 if (bytes_to_clear
) {
589 ret
= blk_pwrite_zeroes(blk
, 0, bytes_to_clear
, BDRV_REQ_MAY_UNMAP
);
591 error_setg_errno(errp
, -ret
,
592 "Failed to clear the new image's first sector");
600 static int bdrv_create_file_fallback(const char *filename
, BlockDriver
*drv
,
601 QemuOpts
*opts
, Error
**errp
)
607 PreallocMode prealloc
;
608 Error
*local_err
= NULL
;
611 size
= qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0);
612 buf
= qemu_opt_get_del(opts
, BLOCK_OPT_PREALLOC
);
613 prealloc
= qapi_enum_parse(&PreallocMode_lookup
, buf
,
614 PREALLOC_MODE_OFF
, &local_err
);
617 error_propagate(errp
, local_err
);
621 if (prealloc
!= PREALLOC_MODE_OFF
) {
622 error_setg(errp
, "Unsupported preallocation mode '%s'",
623 PreallocMode_str(prealloc
));
627 options
= qdict_new();
628 qdict_put_str(options
, "driver", drv
->format_name
);
630 blk
= blk_new_open(filename
, NULL
, options
,
631 BDRV_O_RDWR
| BDRV_O_RESIZE
, errp
);
633 error_prepend(errp
, "Protocol driver '%s' does not support image "
634 "creation, and opening the image failed: ",
639 size
= create_file_fallback_truncate(blk
, size
, errp
);
645 ret
= create_file_fallback_zero_first_sector(blk
, size
, errp
);
656 int bdrv_create_file(const char *filename
, QemuOpts
*opts
, Error
**errp
)
660 drv
= bdrv_find_protocol(filename
, true, errp
);
665 if (drv
->bdrv_co_create_opts
) {
666 return bdrv_create(drv
, filename
, opts
, errp
);
668 return bdrv_create_file_fallback(filename
, drv
, opts
, errp
);
672 int coroutine_fn
bdrv_co_delete_file(BlockDriverState
*bs
, Error
**errp
)
674 Error
*local_err
= NULL
;
680 error_setg(errp
, "Block node '%s' is not opened", bs
->filename
);
684 if (!bs
->drv
->bdrv_co_delete_file
) {
685 error_setg(errp
, "Driver '%s' does not support image deletion",
686 bs
->drv
->format_name
);
690 ret
= bs
->drv
->bdrv_co_delete_file(bs
, &local_err
);
692 error_propagate(errp
, local_err
);
699 * Try to get @bs's logical and physical block size.
700 * On success, store them in @bsz struct and return 0.
701 * On failure return -errno.
702 * @bs must not be empty.
704 int bdrv_probe_blocksizes(BlockDriverState
*bs
, BlockSizes
*bsz
)
706 BlockDriver
*drv
= bs
->drv
;
708 if (drv
&& drv
->bdrv_probe_blocksizes
) {
709 return drv
->bdrv_probe_blocksizes(bs
, bsz
);
710 } else if (drv
&& drv
->is_filter
&& bs
->file
) {
711 return bdrv_probe_blocksizes(bs
->file
->bs
, bsz
);
718 * Try to get @bs's geometry (cyls, heads, sectors).
719 * On success, store them in @geo struct and return 0.
720 * On failure return -errno.
721 * @bs must not be empty.
723 int bdrv_probe_geometry(BlockDriverState
*bs
, HDGeometry
*geo
)
725 BlockDriver
*drv
= bs
->drv
;
727 if (drv
&& drv
->bdrv_probe_geometry
) {
728 return drv
->bdrv_probe_geometry(bs
, geo
);
729 } else if (drv
&& drv
->is_filter
&& bs
->file
) {
730 return bdrv_probe_geometry(bs
->file
->bs
, geo
);
737 * Create a uniquely-named empty temporary file.
738 * Return 0 upon success, otherwise a negative errno value.
740 int get_tmp_filename(char *filename
, int size
)
743 char temp_dir
[MAX_PATH
];
744 /* GetTempFileName requires that its output buffer (4th param)
745 have length MAX_PATH or greater. */
746 assert(size
>= MAX_PATH
);
747 return (GetTempPath(MAX_PATH
, temp_dir
)
748 && GetTempFileName(temp_dir
, "qem", 0, filename
)
749 ?
0 : -GetLastError());
753 tmpdir
= getenv("TMPDIR");
757 if (snprintf(filename
, size
, "%s/vl.XXXXXX", tmpdir
) >= size
) {
760 fd
= mkstemp(filename
);
764 if (close(fd
) != 0) {
773 * Detect host devices. By convention, /dev/cdrom[N] is always
774 * recognized as a host CDROM.
776 static BlockDriver
*find_hdev_driver(const char *filename
)
778 int score_max
= 0, score
;
779 BlockDriver
*drv
= NULL
, *d
;
781 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
782 if (d
->bdrv_probe_device
) {
783 score
= d
->bdrv_probe_device(filename
);
784 if (score
> score_max
) {
794 static BlockDriver
*bdrv_do_find_protocol(const char *protocol
)
798 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
799 if (drv1
->protocol_name
&& !strcmp(drv1
->protocol_name
, protocol
)) {
807 BlockDriver
*bdrv_find_protocol(const char *filename
,
808 bool allow_protocol_prefix
,
817 /* TODO Drivers without bdrv_file_open must be specified explicitly */
820 * XXX(hch): we really should not let host device detection
821 * override an explicit protocol specification, but moving this
822 * later breaks access to device names with colons in them.
823 * Thanks to the brain-dead persistent naming schemes on udev-
824 * based Linux systems those actually are quite common.
826 drv1
= find_hdev_driver(filename
);
831 if (!path_has_protocol(filename
) || !allow_protocol_prefix
) {
835 p
= strchr(filename
, ':');
838 if (len
> sizeof(protocol
) - 1)
839 len
= sizeof(protocol
) - 1;
840 memcpy(protocol
, filename
, len
);
841 protocol
[len
] = '\0';
843 drv1
= bdrv_do_find_protocol(protocol
);
848 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
849 if (block_driver_modules
[i
].protocol_name
&&
850 !strcmp(block_driver_modules
[i
].protocol_name
, protocol
)) {
851 block_module_load_one(block_driver_modules
[i
].library_name
);
856 drv1
= bdrv_do_find_protocol(protocol
);
858 error_setg(errp
, "Unknown protocol '%s'", protocol
);
864 * Guess image format by probing its contents.
865 * This is not a good idea when your image is raw (CVE-2008-2004), but
866 * we do it anyway for backward compatibility.
868 * @buf contains the image's first @buf_size bytes.
869 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
870 * but can be smaller if the image file is smaller)
871 * @filename is its filename.
873 * For all block drivers, call the bdrv_probe() method to get its
875 * Return the first block driver with the highest probing score.
877 BlockDriver
*bdrv_probe_all(const uint8_t *buf
, int buf_size
,
878 const char *filename
)
880 int score_max
= 0, score
;
881 BlockDriver
*drv
= NULL
, *d
;
883 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
885 score
= d
->bdrv_probe(buf
, buf_size
, filename
);
886 if (score
> score_max
) {
896 static int find_image_format(BlockBackend
*file
, const char *filename
,
897 BlockDriver
**pdrv
, Error
**errp
)
900 uint8_t buf
[BLOCK_PROBE_BUF_SIZE
];
903 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
904 if (blk_is_sg(file
) || !blk_is_inserted(file
) || blk_getlength(file
) == 0) {
909 ret
= blk_pread(file
, 0, buf
, sizeof(buf
));
911 error_setg_errno(errp
, -ret
, "Could not read image for determining its "
917 drv
= bdrv_probe_all(buf
, ret
, filename
);
919 error_setg(errp
, "Could not determine image format: No compatible "
928 * Set the current 'total_sectors' value
929 * Return 0 on success, -errno on error.
931 int refresh_total_sectors(BlockDriverState
*bs
, int64_t hint
)
933 BlockDriver
*drv
= bs
->drv
;
939 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
943 /* query actual device if possible, otherwise just trust the hint */
944 if (drv
->bdrv_getlength
) {
945 int64_t length
= drv
->bdrv_getlength(bs
);
949 hint
= DIV_ROUND_UP(length
, BDRV_SECTOR_SIZE
);
952 bs
->total_sectors
= hint
;
957 * Combines a QDict of new block driver @options with any missing options taken
958 * from @old_options, so that leaving out an option defaults to its old value.
960 static void bdrv_join_options(BlockDriverState
*bs
, QDict
*options
,
963 if (bs
->drv
&& bs
->drv
->bdrv_join_options
) {
964 bs
->drv
->bdrv_join_options(options
, old_options
);
966 qdict_join(options
, old_options
, false);
970 static BlockdevDetectZeroesOptions
bdrv_parse_detect_zeroes(QemuOpts
*opts
,
974 Error
*local_err
= NULL
;
975 char *value
= qemu_opt_get_del(opts
, "detect-zeroes");
976 BlockdevDetectZeroesOptions detect_zeroes
=
977 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup
, value
,
978 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF
, &local_err
);
981 error_propagate(errp
, local_err
);
982 return detect_zeroes
;
985 if (detect_zeroes
== BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP
&&
986 !(open_flags
& BDRV_O_UNMAP
))
988 error_setg(errp
, "setting detect-zeroes to unmap is not allowed "
989 "without setting discard operation to unmap");
992 return detect_zeroes
;
996 * Set open flags for aio engine
998 * Return 0 on success, -1 if the engine specified is invalid
1000 int bdrv_parse_aio(const char *mode
, int *flags
)
1002 if (!strcmp(mode
, "threads")) {
1003 /* do nothing, default */
1004 } else if (!strcmp(mode
, "native")) {
1005 *flags
|= BDRV_O_NATIVE_AIO
;
1006 #ifdef CONFIG_LINUX_IO_URING
1007 } else if (!strcmp(mode
, "io_uring")) {
1008 *flags
|= BDRV_O_IO_URING
;
1018 * Set open flags for a given discard mode
1020 * Return 0 on success, -1 if the discard mode was invalid.
1022 int bdrv_parse_discard_flags(const char *mode
, int *flags
)
1024 *flags
&= ~BDRV_O_UNMAP
;
1026 if (!strcmp(mode
, "off") || !strcmp(mode
, "ignore")) {
1028 } else if (!strcmp(mode
, "on") || !strcmp(mode
, "unmap")) {
1029 *flags
|= BDRV_O_UNMAP
;
1038 * Set open flags for a given cache mode
1040 * Return 0 on success, -1 if the cache mode was invalid.
1042 int bdrv_parse_cache_mode(const char *mode
, int *flags
, bool *writethrough
)
1044 *flags
&= ~BDRV_O_CACHE_MASK
;
1046 if (!strcmp(mode
, "off") || !strcmp(mode
, "none")) {
1047 *writethrough
= false;
1048 *flags
|= BDRV_O_NOCACHE
;
1049 } else if (!strcmp(mode
, "directsync")) {
1050 *writethrough
= true;
1051 *flags
|= BDRV_O_NOCACHE
;
1052 } else if (!strcmp(mode
, "writeback")) {
1053 *writethrough
= false;
1054 } else if (!strcmp(mode
, "unsafe")) {
1055 *writethrough
= false;
1056 *flags
|= BDRV_O_NO_FLUSH
;
1057 } else if (!strcmp(mode
, "writethrough")) {
1058 *writethrough
= true;
1066 static char *bdrv_child_get_parent_desc(BdrvChild
*c
)
1068 BlockDriverState
*parent
= c
->opaque
;
1069 return g_strdup(bdrv_get_device_or_node_name(parent
));
1072 static void bdrv_child_cb_drained_begin(BdrvChild
*child
)
1074 BlockDriverState
*bs
= child
->opaque
;
1075 bdrv_do_drained_begin_quiesce(bs
, NULL
, false);
1078 static bool bdrv_child_cb_drained_poll(BdrvChild
*child
)
1080 BlockDriverState
*bs
= child
->opaque
;
1081 return bdrv_drain_poll(bs
, false, NULL
, false);
1084 static void bdrv_child_cb_drained_end(BdrvChild
*child
,
1085 int *drained_end_counter
)
1087 BlockDriverState
*bs
= child
->opaque
;
1088 bdrv_drained_end_no_poll(bs
, drained_end_counter
);
1091 static void bdrv_child_cb_attach(BdrvChild
*child
)
1093 BlockDriverState
*bs
= child
->opaque
;
1094 bdrv_apply_subtree_drain(child
, bs
);
1097 static void bdrv_child_cb_detach(BdrvChild
*child
)
1099 BlockDriverState
*bs
= child
->opaque
;
1100 bdrv_unapply_subtree_drain(child
, bs
);
1103 static int bdrv_child_cb_inactivate(BdrvChild
*child
)
1105 BlockDriverState
*bs
= child
->opaque
;
1106 assert(bs
->open_flags
& BDRV_O_INACTIVE
);
1110 static bool bdrv_child_cb_can_set_aio_ctx(BdrvChild
*child
, AioContext
*ctx
,
1111 GSList
**ignore
, Error
**errp
)
1113 BlockDriverState
*bs
= child
->opaque
;
1114 return bdrv_can_set_aio_context(bs
, ctx
, ignore
, errp
);
1117 static void bdrv_child_cb_set_aio_ctx(BdrvChild
*child
, AioContext
*ctx
,
1120 BlockDriverState
*bs
= child
->opaque
;
1121 return bdrv_set_aio_context_ignore(bs
, ctx
, ignore
);
1125 * Returns the options and flags that a temporary snapshot should get, based on
1126 * the originally requested flags (the originally requested image will have
1127 * flags like a backing file)
1129 static void bdrv_temp_snapshot_options(int *child_flags
, QDict
*child_options
,
1130 int parent_flags
, QDict
*parent_options
)
1132 *child_flags
= (parent_flags
& ~BDRV_O_SNAPSHOT
) | BDRV_O_TEMPORARY
;
1134 /* For temporary files, unconditional cache=unsafe is fine */
1135 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_DIRECT
, "off");
1136 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_NO_FLUSH
, "on");
1138 /* Copy the read-only and discard options from the parent */
1139 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1140 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_DISCARD
);
1142 /* aio=native doesn't work for cache.direct=off, so disable it for the
1143 * temporary snapshot */
1144 *child_flags
&= ~BDRV_O_NATIVE_AIO
;
1148 * Returns the options and flags that bs->file should get if a protocol driver
1149 * is expected, based on the given options and flags for the parent BDS
1151 static void bdrv_inherited_options(int *child_flags
, QDict
*child_options
,
1152 int parent_flags
, QDict
*parent_options
)
1154 int flags
= parent_flags
;
1156 /* Enable protocol handling, disable format probing for bs->file */
1157 flags
|= BDRV_O_PROTOCOL
;
1159 /* If the cache mode isn't explicitly set, inherit direct and no-flush from
1161 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_DIRECT
);
1162 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_NO_FLUSH
);
1163 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_FORCE_SHARE
);
1165 /* Inherit the read-only option from the parent if it's not set */
1166 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1167 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_AUTO_READ_ONLY
);
1169 /* Our block drivers take care to send flushes and respect unmap policy,
1170 * so we can default to enable both on lower layers regardless of the
1171 * corresponding parent options. */
1172 qdict_set_default_str(child_options
, BDRV_OPT_DISCARD
, "unmap");
1174 /* Clear flags that only apply to the top layer */
1175 flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_COPY_ON_READ
|
1178 *child_flags
= flags
;
1181 const BdrvChildRole child_file
= {
1182 .parent_is_bds
= true,
1183 .get_parent_desc
= bdrv_child_get_parent_desc
,
1184 .inherit_options
= bdrv_inherited_options
,
1185 .drained_begin
= bdrv_child_cb_drained_begin
,
1186 .drained_poll
= bdrv_child_cb_drained_poll
,
1187 .drained_end
= bdrv_child_cb_drained_end
,
1188 .attach
= bdrv_child_cb_attach
,
1189 .detach
= bdrv_child_cb_detach
,
1190 .inactivate
= bdrv_child_cb_inactivate
,
1191 .can_set_aio_ctx
= bdrv_child_cb_can_set_aio_ctx
,
1192 .set_aio_ctx
= bdrv_child_cb_set_aio_ctx
,
1196 * Returns the options and flags that bs->file should get if the use of formats
1197 * (and not only protocols) is permitted for it, based on the given options and
1198 * flags for the parent BDS
1200 static void bdrv_inherited_fmt_options(int *child_flags
, QDict
*child_options
,
1201 int parent_flags
, QDict
*parent_options
)
1203 child_file
.inherit_options(child_flags
, child_options
,
1204 parent_flags
, parent_options
);
1206 *child_flags
&= ~(BDRV_O_PROTOCOL
| BDRV_O_NO_IO
);
1209 const BdrvChildRole child_format
= {
1210 .parent_is_bds
= true,
1211 .get_parent_desc
= bdrv_child_get_parent_desc
,
1212 .inherit_options
= bdrv_inherited_fmt_options
,
1213 .drained_begin
= bdrv_child_cb_drained_begin
,
1214 .drained_poll
= bdrv_child_cb_drained_poll
,
1215 .drained_end
= bdrv_child_cb_drained_end
,
1216 .attach
= bdrv_child_cb_attach
,
1217 .detach
= bdrv_child_cb_detach
,
1218 .inactivate
= bdrv_child_cb_inactivate
,
1219 .can_set_aio_ctx
= bdrv_child_cb_can_set_aio_ctx
,
1220 .set_aio_ctx
= bdrv_child_cb_set_aio_ctx
,
1223 static void bdrv_backing_attach(BdrvChild
*c
)
1225 BlockDriverState
*parent
= c
->opaque
;
1226 BlockDriverState
*backing_hd
= c
->bs
;
1228 assert(!parent
->backing_blocker
);
1229 error_setg(&parent
->backing_blocker
,
1230 "node is used as backing hd of '%s'",
1231 bdrv_get_device_or_node_name(parent
));
1233 bdrv_refresh_filename(backing_hd
);
1235 parent
->open_flags
&= ~BDRV_O_NO_BACKING
;
1236 pstrcpy(parent
->backing_file
, sizeof(parent
->backing_file
),
1237 backing_hd
->filename
);
1238 pstrcpy(parent
->backing_format
, sizeof(parent
->backing_format
),
1239 backing_hd
->drv ? backing_hd
->drv
->format_name
: "");
1241 bdrv_op_block_all(backing_hd
, parent
->backing_blocker
);
1242 /* Otherwise we won't be able to commit or stream */
1243 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_COMMIT_TARGET
,
1244 parent
->backing_blocker
);
1245 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_STREAM
,
1246 parent
->backing_blocker
);
1248 * We do backup in 3 ways:
1250 * The target bs is new opened, and the source is top BDS
1251 * 2. blockdev backup
1252 * Both the source and the target are top BDSes.
1253 * 3. internal backup(used for block replication)
1254 * Both the source and the target are backing file
1256 * In case 1 and 2, neither the source nor the target is the backing file.
1257 * In case 3, we will block the top BDS, so there is only one block job
1258 * for the top BDS and its backing chain.
1260 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_SOURCE
,
1261 parent
->backing_blocker
);
1262 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_TARGET
,
1263 parent
->backing_blocker
);
1265 bdrv_child_cb_attach(c
);
1268 static void bdrv_backing_detach(BdrvChild
*c
)
1270 BlockDriverState
*parent
= c
->opaque
;
1272 assert(parent
->backing_blocker
);
1273 bdrv_op_unblock_all(c
->bs
, parent
->backing_blocker
);
1274 error_free(parent
->backing_blocker
);
1275 parent
->backing_blocker
= NULL
;
1277 bdrv_child_cb_detach(c
);
1281 * Returns the options and flags that bs->backing should get, based on the
1282 * given options and flags for the parent BDS
1284 static void bdrv_backing_options(int *child_flags
, QDict
*child_options
,
1285 int parent_flags
, QDict
*parent_options
)
1287 int flags
= parent_flags
;
1289 /* The cache mode is inherited unmodified for backing files; except WCE,
1290 * which is only applied on the top level (BlockBackend) */
1291 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_DIRECT
);
1292 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_NO_FLUSH
);
1293 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_FORCE_SHARE
);
1295 /* backing files always opened read-only */
1296 qdict_set_default_str(child_options
, BDRV_OPT_READ_ONLY
, "on");
1297 qdict_set_default_str(child_options
, BDRV_OPT_AUTO_READ_ONLY
, "off");
1298 flags
&= ~BDRV_O_COPY_ON_READ
;
1300 /* snapshot=on is handled on the top layer */
1301 flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_TEMPORARY
);
1303 *child_flags
= flags
;
1306 static int bdrv_backing_update_filename(BdrvChild
*c
, BlockDriverState
*base
,
1307 const char *filename
, Error
**errp
)
1309 BlockDriverState
*parent
= c
->opaque
;
1310 bool read_only
= bdrv_is_read_only(parent
);
1314 ret
= bdrv_reopen_set_read_only(parent
, false, errp
);
1320 ret
= bdrv_change_backing_file(parent
, filename
,
1321 base
->drv ? base
->drv
->format_name
: "");
1323 error_setg_errno(errp
, -ret
, "Could not update backing file link");
1327 bdrv_reopen_set_read_only(parent
, true, NULL
);
1333 const BdrvChildRole child_backing
= {
1334 .parent_is_bds
= true,
1335 .get_parent_desc
= bdrv_child_get_parent_desc
,
1336 .attach
= bdrv_backing_attach
,
1337 .detach
= bdrv_backing_detach
,
1338 .inherit_options
= bdrv_backing_options
,
1339 .drained_begin
= bdrv_child_cb_drained_begin
,
1340 .drained_poll
= bdrv_child_cb_drained_poll
,
1341 .drained_end
= bdrv_child_cb_drained_end
,
1342 .inactivate
= bdrv_child_cb_inactivate
,
1343 .update_filename
= bdrv_backing_update_filename
,
1344 .can_set_aio_ctx
= bdrv_child_cb_can_set_aio_ctx
,
1345 .set_aio_ctx
= bdrv_child_cb_set_aio_ctx
,
1348 static int bdrv_open_flags(BlockDriverState
*bs
, int flags
)
1350 int open_flags
= flags
;
1353 * Clear flags that are internal to the block layer before opening the
1356 open_flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_PROTOCOL
);
1361 static void update_flags_from_options(int *flags
, QemuOpts
*opts
)
1363 *flags
&= ~(BDRV_O_CACHE_MASK
| BDRV_O_RDWR
| BDRV_O_AUTO_RDONLY
);
1365 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_NO_FLUSH
, false)) {
1366 *flags
|= BDRV_O_NO_FLUSH
;
1369 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_DIRECT
, false)) {
1370 *flags
|= BDRV_O_NOCACHE
;
1373 if (!qemu_opt_get_bool_del(opts
, BDRV_OPT_READ_ONLY
, false)) {
1374 *flags
|= BDRV_O_RDWR
;
1377 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_AUTO_READ_ONLY
, false)) {
1378 *flags
|= BDRV_O_AUTO_RDONLY
;
1382 static void update_options_from_flags(QDict
*options
, int flags
)
1384 if (!qdict_haskey(options
, BDRV_OPT_CACHE_DIRECT
)) {
1385 qdict_put_bool(options
, BDRV_OPT_CACHE_DIRECT
, flags
& BDRV_O_NOCACHE
);
1387 if (!qdict_haskey(options
, BDRV_OPT_CACHE_NO_FLUSH
)) {
1388 qdict_put_bool(options
, BDRV_OPT_CACHE_NO_FLUSH
,
1389 flags
& BDRV_O_NO_FLUSH
);
1391 if (!qdict_haskey(options
, BDRV_OPT_READ_ONLY
)) {
1392 qdict_put_bool(options
, BDRV_OPT_READ_ONLY
, !(flags
& BDRV_O_RDWR
));
1394 if (!qdict_haskey(options
, BDRV_OPT_AUTO_READ_ONLY
)) {
1395 qdict_put_bool(options
, BDRV_OPT_AUTO_READ_ONLY
,
1396 flags
& BDRV_O_AUTO_RDONLY
);
1400 static void bdrv_assign_node_name(BlockDriverState
*bs
,
1401 const char *node_name
,
1404 char *gen_node_name
= NULL
;
1407 node_name
= gen_node_name
= id_generate(ID_BLOCK
);
1408 } else if (!id_wellformed(node_name
)) {
1410 * Check for empty string or invalid characters, but not if it is
1411 * generated (generated names use characters not available to the user)
1413 error_setg(errp
, "Invalid node name");
1417 /* takes care of avoiding namespaces collisions */
1418 if (blk_by_name(node_name
)) {
1419 error_setg(errp
, "node-name=%s is conflicting with a device id",
1424 /* takes care of avoiding duplicates node names */
1425 if (bdrv_find_node(node_name
)) {
1426 error_setg(errp
, "Duplicate node name");
1430 /* Make sure that the node name isn't truncated */
1431 if (strlen(node_name
) >= sizeof(bs
->node_name
)) {
1432 error_setg(errp
, "Node name too long");
1436 /* copy node name into the bs and insert it into the graph list */
1437 pstrcpy(bs
->node_name
, sizeof(bs
->node_name
), node_name
);
1438 QTAILQ_INSERT_TAIL(&graph_bdrv_states
, bs
, node_list
);
1440 g_free(gen_node_name
);
1443 static int bdrv_open_driver(BlockDriverState
*bs
, BlockDriver
*drv
,
1444 const char *node_name
, QDict
*options
,
1445 int open_flags
, Error
**errp
)
1447 Error
*local_err
= NULL
;
1450 bdrv_assign_node_name(bs
, node_name
, &local_err
);
1452 error_propagate(errp
, local_err
);
1457 bs
->read_only
= !(bs
->open_flags
& BDRV_O_RDWR
);
1458 bs
->opaque
= g_malloc0(drv
->instance_size
);
1460 if (drv
->bdrv_file_open
) {
1461 assert(!drv
->bdrv_needs_filename
|| bs
->filename
[0]);
1462 ret
= drv
->bdrv_file_open(bs
, options
, open_flags
, &local_err
);
1463 } else if (drv
->bdrv_open
) {
1464 ret
= drv
->bdrv_open(bs
, options
, open_flags
, &local_err
);
1471 error_propagate(errp
, local_err
);
1472 } else if (bs
->filename
[0]) {
1473 error_setg_errno(errp
, -ret
, "Could not open '%s'", bs
->filename
);
1475 error_setg_errno(errp
, -ret
, "Could not open image");
1480 ret
= refresh_total_sectors(bs
, bs
->total_sectors
);
1482 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
1486 bdrv_refresh_limits(bs
, &local_err
);
1488 error_propagate(errp
, local_err
);
1492 assert(bdrv_opt_mem_align(bs
) != 0);
1493 assert(bdrv_min_mem_align(bs
) != 0);
1494 assert(is_power_of_2(bs
->bl
.request_alignment
));
1496 for (i
= 0; i
< bs
->quiesce_counter
; i
++) {
1497 if (drv
->bdrv_co_drain_begin
) {
1498 drv
->bdrv_co_drain_begin(bs
);
1505 if (bs
->file
!= NULL
) {
1506 bdrv_unref_child(bs
, bs
->file
);
1514 BlockDriverState
*bdrv_new_open_driver(BlockDriver
*drv
, const char *node_name
,
1515 int flags
, Error
**errp
)
1517 BlockDriverState
*bs
;
1521 bs
->open_flags
= flags
;
1522 bs
->explicit_options
= qdict_new();
1523 bs
->options
= qdict_new();
1526 update_options_from_flags(bs
->options
, flags
);
1528 ret
= bdrv_open_driver(bs
, drv
, node_name
, bs
->options
, flags
, errp
);
1530 qobject_unref(bs
->explicit_options
);
1531 bs
->explicit_options
= NULL
;
1532 qobject_unref(bs
->options
);
1541 QemuOptsList bdrv_runtime_opts
= {
1542 .name
= "bdrv_common",
1543 .head
= QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts
.head
),
1546 .name
= "node-name",
1547 .type
= QEMU_OPT_STRING
,
1548 .help
= "Node name of the block device node",
1552 .type
= QEMU_OPT_STRING
,
1553 .help
= "Block driver to use for the node",
1556 .name
= BDRV_OPT_CACHE_DIRECT
,
1557 .type
= QEMU_OPT_BOOL
,
1558 .help
= "Bypass software writeback cache on the host",
1561 .name
= BDRV_OPT_CACHE_NO_FLUSH
,
1562 .type
= QEMU_OPT_BOOL
,
1563 .help
= "Ignore flush requests",
1566 .name
= BDRV_OPT_READ_ONLY
,
1567 .type
= QEMU_OPT_BOOL
,
1568 .help
= "Node is opened in read-only mode",
1571 .name
= BDRV_OPT_AUTO_READ_ONLY
,
1572 .type
= QEMU_OPT_BOOL
,
1573 .help
= "Node can become read-only if opening read-write fails",
1576 .name
= "detect-zeroes",
1577 .type
= QEMU_OPT_STRING
,
1578 .help
= "try to optimize zero writes (off, on, unmap)",
1581 .name
= BDRV_OPT_DISCARD
,
1582 .type
= QEMU_OPT_STRING
,
1583 .help
= "discard operation (ignore/off, unmap/on)",
1586 .name
= BDRV_OPT_FORCE_SHARE
,
1587 .type
= QEMU_OPT_BOOL
,
1588 .help
= "always accept other writers (default: off)",
1590 { /* end of list */ }
1594 static QemuOptsList fallback_create_opts
= {
1595 .name
= "fallback-create-opts",
1596 .head
= QTAILQ_HEAD_INITIALIZER(fallback_create_opts
.head
),
1599 .name
= BLOCK_OPT_SIZE
,
1600 .type
= QEMU_OPT_SIZE
,
1601 .help
= "Virtual disk size"
1604 .name
= BLOCK_OPT_PREALLOC
,
1605 .type
= QEMU_OPT_STRING
,
1606 .help
= "Preallocation mode (allowed values: off)"
1608 { /* end of list */ }
1613 * Common part for opening disk images and files
1615 * Removes all processed options from *options.
1617 static int bdrv_open_common(BlockDriverState
*bs
, BlockBackend
*file
,
1618 QDict
*options
, Error
**errp
)
1620 int ret
, open_flags
;
1621 const char *filename
;
1622 const char *driver_name
= NULL
;
1623 const char *node_name
= NULL
;
1624 const char *discard
;
1627 Error
*local_err
= NULL
;
1629 assert(bs
->file
== NULL
);
1630 assert(options
!= NULL
&& bs
->options
!= options
);
1632 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
1633 qemu_opts_absorb_qdict(opts
, options
, &local_err
);
1635 error_propagate(errp
, local_err
);
1640 update_flags_from_options(&bs
->open_flags
, opts
);
1642 driver_name
= qemu_opt_get(opts
, "driver");
1643 drv
= bdrv_find_format(driver_name
);
1644 assert(drv
!= NULL
);
1646 bs
->force_share
= qemu_opt_get_bool(opts
, BDRV_OPT_FORCE_SHARE
, false);
1648 if (bs
->force_share
&& (bs
->open_flags
& BDRV_O_RDWR
)) {
1650 BDRV_OPT_FORCE_SHARE
1651 "=on can only be used with read-only images");
1657 bdrv_refresh_filename(blk_bs(file
));
1658 filename
= blk_bs(file
)->filename
;
1661 * Caution: while qdict_get_try_str() is fine, getting
1662 * non-string types would require more care. When @options
1663 * come from -blockdev or blockdev_add, its members are typed
1664 * according to the QAPI schema, but when they come from
1665 * -drive, they're all QString.
1667 filename
= qdict_get_try_str(options
, "filename");
1670 if (drv
->bdrv_needs_filename
&& (!filename
|| !filename
[0])) {
1671 error_setg(errp
, "The '%s' block driver requires a file name",
1677 trace_bdrv_open_common(bs
, filename ?
: "", bs
->open_flags
,
1680 bs
->read_only
= !(bs
->open_flags
& BDRV_O_RDWR
);
1682 if (use_bdrv_whitelist
&& !bdrv_is_whitelisted(drv
, bs
->read_only
)) {
1683 if (!bs
->read_only
&& bdrv_is_whitelisted(drv
, true)) {
1684 ret
= bdrv_apply_auto_read_only(bs
, NULL
, NULL
);
1690 !bs
->read_only
&& bdrv_is_whitelisted(drv
, true)
1691 ?
"Driver '%s' can only be used for read-only devices"
1692 : "Driver '%s' is not whitelisted",
1698 /* bdrv_new() and bdrv_close() make it so */
1699 assert(atomic_read(&bs
->copy_on_read
) == 0);
1701 if (bs
->open_flags
& BDRV_O_COPY_ON_READ
) {
1702 if (!bs
->read_only
) {
1703 bdrv_enable_copy_on_read(bs
);
1705 error_setg(errp
, "Can't use copy-on-read on read-only device");
1711 discard
= qemu_opt_get(opts
, BDRV_OPT_DISCARD
);
1712 if (discard
!= NULL
) {
1713 if (bdrv_parse_discard_flags(discard
, &bs
->open_flags
) != 0) {
1714 error_setg(errp
, "Invalid discard option");
1721 bdrv_parse_detect_zeroes(opts
, bs
->open_flags
, &local_err
);
1723 error_propagate(errp
, local_err
);
1728 if (filename
!= NULL
) {
1729 pstrcpy(bs
->filename
, sizeof(bs
->filename
), filename
);
1731 bs
->filename
[0] = '\0';
1733 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
), bs
->filename
);
1735 /* Open the image, either directly or using a protocol */
1736 open_flags
= bdrv_open_flags(bs
, bs
->open_flags
);
1737 node_name
= qemu_opt_get(opts
, "node-name");
1739 assert(!drv
->bdrv_file_open
|| file
== NULL
);
1740 ret
= bdrv_open_driver(bs
, drv
, node_name
, options
, open_flags
, errp
);
1745 qemu_opts_del(opts
);
1749 qemu_opts_del(opts
);
1753 static QDict
*parse_json_filename(const char *filename
, Error
**errp
)
1755 QObject
*options_obj
;
1759 ret
= strstart(filename
, "json:", &filename
);
1762 options_obj
= qobject_from_json(filename
, errp
);
1764 error_prepend(errp
, "Could not parse the JSON options: ");
1768 options
= qobject_to(QDict
, options_obj
);
1770 qobject_unref(options_obj
);
1771 error_setg(errp
, "Invalid JSON object given");
1775 qdict_flatten(options
);
1780 static void parse_json_protocol(QDict
*options
, const char **pfilename
,
1783 QDict
*json_options
;
1784 Error
*local_err
= NULL
;
1786 /* Parse json: pseudo-protocol */
1787 if (!*pfilename
|| !g_str_has_prefix(*pfilename
, "json:")) {
1791 json_options
= parse_json_filename(*pfilename
, &local_err
);
1793 error_propagate(errp
, local_err
);
1797 /* Options given in the filename have lower priority than options
1798 * specified directly */
1799 qdict_join(options
, json_options
, false);
1800 qobject_unref(json_options
);
1805 * Fills in default options for opening images and converts the legacy
1806 * filename/flags pair to option QDict entries.
1807 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1808 * block driver has been specified explicitly.
1810 static int bdrv_fill_options(QDict
**options
, const char *filename
,
1811 int *flags
, Error
**errp
)
1813 const char *drvname
;
1814 bool protocol
= *flags
& BDRV_O_PROTOCOL
;
1815 bool parse_filename
= false;
1816 BlockDriver
*drv
= NULL
;
1817 Error
*local_err
= NULL
;
1820 * Caution: while qdict_get_try_str() is fine, getting non-string
1821 * types would require more care. When @options come from
1822 * -blockdev or blockdev_add, its members are typed according to
1823 * the QAPI schema, but when they come from -drive, they're all
1826 drvname
= qdict_get_try_str(*options
, "driver");
1828 drv
= bdrv_find_format(drvname
);
1830 error_setg(errp
, "Unknown driver '%s'", drvname
);
1833 /* If the user has explicitly specified the driver, this choice should
1834 * override the BDRV_O_PROTOCOL flag */
1835 protocol
= drv
->bdrv_file_open
;
1839 *flags
|= BDRV_O_PROTOCOL
;
1841 *flags
&= ~BDRV_O_PROTOCOL
;
1844 /* Translate cache options from flags into options */
1845 update_options_from_flags(*options
, *flags
);
1847 /* Fetch the file name from the options QDict if necessary */
1848 if (protocol
&& filename
) {
1849 if (!qdict_haskey(*options
, "filename")) {
1850 qdict_put_str(*options
, "filename", filename
);
1851 parse_filename
= true;
1853 error_setg(errp
, "Can't specify 'file' and 'filename' options at "
1859 /* Find the right block driver */
1860 /* See cautionary note on accessing @options above */
1861 filename
= qdict_get_try_str(*options
, "filename");
1863 if (!drvname
&& protocol
) {
1865 drv
= bdrv_find_protocol(filename
, parse_filename
, errp
);
1870 drvname
= drv
->format_name
;
1871 qdict_put_str(*options
, "driver", drvname
);
1873 error_setg(errp
, "Must specify either driver or file");
1878 assert(drv
|| !protocol
);
1880 /* Driver-specific filename parsing */
1881 if (drv
&& drv
->bdrv_parse_filename
&& parse_filename
) {
1882 drv
->bdrv_parse_filename(filename
, *options
, &local_err
);
1884 error_propagate(errp
, local_err
);
1888 if (!drv
->bdrv_needs_filename
) {
1889 qdict_del(*options
, "filename");
1896 static int bdrv_child_check_perm(BdrvChild
*c
, BlockReopenQueue
*q
,
1897 uint64_t perm
, uint64_t shared
,
1898 GSList
*ignore_children
,
1899 bool *tighten_restrictions
, Error
**errp
);
1900 static void bdrv_child_abort_perm_update(BdrvChild
*c
);
1901 static void bdrv_child_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
);
1903 typedef struct BlockReopenQueueEntry
{
1906 BDRVReopenState state
;
1907 QTAILQ_ENTRY(BlockReopenQueueEntry
) entry
;
1908 } BlockReopenQueueEntry
;
1911 * Return the flags that @bs will have after the reopens in @q have
1912 * successfully completed. If @q is NULL (or @bs is not contained in @q),
1913 * return the current flags.
1915 static int bdrv_reopen_get_flags(BlockReopenQueue
*q
, BlockDriverState
*bs
)
1917 BlockReopenQueueEntry
*entry
;
1920 QTAILQ_FOREACH(entry
, q
, entry
) {
1921 if (entry
->state
.bs
== bs
) {
1922 return entry
->state
.flags
;
1927 return bs
->open_flags
;
1930 /* Returns whether the image file can be written to after the reopen queue @q
1931 * has been successfully applied, or right now if @q is NULL. */
1932 static bool bdrv_is_writable_after_reopen(BlockDriverState
*bs
,
1933 BlockReopenQueue
*q
)
1935 int flags
= bdrv_reopen_get_flags(q
, bs
);
1937 return (flags
& (BDRV_O_RDWR
| BDRV_O_INACTIVE
)) == BDRV_O_RDWR
;
1941 * Return whether the BDS can be written to. This is not necessarily
1942 * the same as !bdrv_is_read_only(bs), as inactivated images may not
1943 * be written to but do not count as read-only images.
1945 bool bdrv_is_writable(BlockDriverState
*bs
)
1947 return bdrv_is_writable_after_reopen(bs
, NULL
);
1950 static void bdrv_child_perm(BlockDriverState
*bs
, BlockDriverState
*child_bs
,
1951 BdrvChild
*c
, const BdrvChildRole
*role
,
1952 BlockReopenQueue
*reopen_queue
,
1953 uint64_t parent_perm
, uint64_t parent_shared
,
1954 uint64_t *nperm
, uint64_t *nshared
)
1956 assert(bs
->drv
&& bs
->drv
->bdrv_child_perm
);
1957 bs
->drv
->bdrv_child_perm(bs
, c
, role
, reopen_queue
,
1958 parent_perm
, parent_shared
,
1960 /* TODO Take force_share from reopen_queue */
1961 if (child_bs
&& child_bs
->force_share
) {
1962 *nshared
= BLK_PERM_ALL
;
1967 * Check whether permissions on this node can be changed in a way that
1968 * @cumulative_perms and @cumulative_shared_perms are the new cumulative
1969 * permissions of all its parents. This involves checking whether all necessary
1970 * permission changes to child nodes can be performed.
1972 * Will set *tighten_restrictions to true if and only if new permissions have to
1973 * be taken or currently shared permissions are to be unshared. Otherwise,
1974 * errors are not fatal as long as the caller accepts that the restrictions
1975 * remain tighter than they need to be. The caller still has to abort the
1977 * @tighten_restrictions cannot be used together with @q: When reopening, we may
1978 * encounter fatal errors even though no restrictions are to be tightened. For
1979 * example, changing a node from RW to RO will fail if the WRITE permission is
1982 * A call to this function must always be followed by a call to bdrv_set_perm()
1983 * or bdrv_abort_perm_update().
1985 static int bdrv_check_perm(BlockDriverState
*bs
, BlockReopenQueue
*q
,
1986 uint64_t cumulative_perms
,
1987 uint64_t cumulative_shared_perms
,
1988 GSList
*ignore_children
,
1989 bool *tighten_restrictions
, Error
**errp
)
1991 BlockDriver
*drv
= bs
->drv
;
1995 assert(!q
|| !tighten_restrictions
);
1997 if (tighten_restrictions
) {
1998 uint64_t current_perms
, current_shared
;
1999 uint64_t added_perms
, removed_shared_perms
;
2001 bdrv_get_cumulative_perm(bs
, ¤t_perms
, ¤t_shared
);
2003 added_perms
= cumulative_perms
& ~current_perms
;
2004 removed_shared_perms
= current_shared
& ~cumulative_shared_perms
;
2006 *tighten_restrictions
= added_perms
|| removed_shared_perms
;
2009 /* Write permissions never work with read-only images */
2010 if ((cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) &&
2011 !bdrv_is_writable_after_reopen(bs
, q
))
2013 if (!bdrv_is_writable_after_reopen(bs
, NULL
)) {
2014 error_setg(errp
, "Block node is read-only");
2016 uint64_t current_perms
, current_shared
;
2017 bdrv_get_cumulative_perm(bs
, ¤t_perms
, ¤t_shared
);
2018 if (current_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) {
2019 error_setg(errp
, "Cannot make block node read-only, there is "
2022 error_setg(errp
, "Cannot make block node read-only and create "
2030 /* Check this node */
2035 if (drv
->bdrv_check_perm
) {
2036 return drv
->bdrv_check_perm(bs
, cumulative_perms
,
2037 cumulative_shared_perms
, errp
);
2040 /* Drivers that never have children can omit .bdrv_child_perm() */
2041 if (!drv
->bdrv_child_perm
) {
2042 assert(QLIST_EMPTY(&bs
->children
));
2046 /* Check all children */
2047 QLIST_FOREACH(c
, &bs
->children
, next
) {
2048 uint64_t cur_perm
, cur_shared
;
2049 bool child_tighten_restr
;
2051 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, q
,
2052 cumulative_perms
, cumulative_shared_perms
,
2053 &cur_perm
, &cur_shared
);
2054 ret
= bdrv_child_check_perm(c
, q
, cur_perm
, cur_shared
, ignore_children
,
2055 tighten_restrictions ?
&child_tighten_restr
2058 if (tighten_restrictions
) {
2059 *tighten_restrictions
|= child_tighten_restr
;
2070 * Notifies drivers that after a previous bdrv_check_perm() call, the
2071 * permission update is not performed and any preparations made for it (e.g.
2072 * taken file locks) need to be undone.
2074 * This function recursively notifies all child nodes.
2076 static void bdrv_abort_perm_update(BlockDriverState
*bs
)
2078 BlockDriver
*drv
= bs
->drv
;
2085 if (drv
->bdrv_abort_perm_update
) {
2086 drv
->bdrv_abort_perm_update(bs
);
2089 QLIST_FOREACH(c
, &bs
->children
, next
) {
2090 bdrv_child_abort_perm_update(c
);
2094 static void bdrv_set_perm(BlockDriverState
*bs
, uint64_t cumulative_perms
,
2095 uint64_t cumulative_shared_perms
)
2097 BlockDriver
*drv
= bs
->drv
;
2104 /* Update this node */
2105 if (drv
->bdrv_set_perm
) {
2106 drv
->bdrv_set_perm(bs
, cumulative_perms
, cumulative_shared_perms
);
2109 /* Drivers that never have children can omit .bdrv_child_perm() */
2110 if (!drv
->bdrv_child_perm
) {
2111 assert(QLIST_EMPTY(&bs
->children
));
2115 /* Update all children */
2116 QLIST_FOREACH(c
, &bs
->children
, next
) {
2117 uint64_t cur_perm
, cur_shared
;
2118 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, NULL
,
2119 cumulative_perms
, cumulative_shared_perms
,
2120 &cur_perm
, &cur_shared
);
2121 bdrv_child_set_perm(c
, cur_perm
, cur_shared
);
2125 void bdrv_get_cumulative_perm(BlockDriverState
*bs
, uint64_t *perm
,
2126 uint64_t *shared_perm
)
2129 uint64_t cumulative_perms
= 0;
2130 uint64_t cumulative_shared_perms
= BLK_PERM_ALL
;
2132 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
2133 cumulative_perms
|= c
->perm
;
2134 cumulative_shared_perms
&= c
->shared_perm
;
2137 *perm
= cumulative_perms
;
2138 *shared_perm
= cumulative_shared_perms
;
2141 static char *bdrv_child_user_desc(BdrvChild
*c
)
2143 if (c
->role
->get_parent_desc
) {
2144 return c
->role
->get_parent_desc(c
);
2147 return g_strdup("another user");
2150 char *bdrv_perm_names(uint64_t perm
)
2156 { BLK_PERM_CONSISTENT_READ
, "consistent read" },
2157 { BLK_PERM_WRITE
, "write" },
2158 { BLK_PERM_WRITE_UNCHANGED
, "write unchanged" },
2159 { BLK_PERM_RESIZE
, "resize" },
2160 { BLK_PERM_GRAPH_MOD
, "change children" },
2164 GString
*result
= g_string_sized_new(30);
2165 struct perm_name
*p
;
2167 for (p
= permissions
; p
->name
; p
++) {
2168 if (perm
& p
->perm
) {
2169 if (result
->len
> 0) {
2170 g_string_append(result
, ", ");
2172 g_string_append(result
, p
->name
);
2176 return g_string_free(result
, FALSE
);
2180 * Checks whether a new reference to @bs can be added if the new user requires
2181 * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is
2182 * set, the BdrvChild objects in this list are ignored in the calculations;
2183 * this allows checking permission updates for an existing reference.
2185 * See bdrv_check_perm() for the semantics of @tighten_restrictions.
2187 * Needs to be followed by a call to either bdrv_set_perm() or
2188 * bdrv_abort_perm_update(). */
2189 static int bdrv_check_update_perm(BlockDriverState
*bs
, BlockReopenQueue
*q
,
2190 uint64_t new_used_perm
,
2191 uint64_t new_shared_perm
,
2192 GSList
*ignore_children
,
2193 bool *tighten_restrictions
,
2197 uint64_t cumulative_perms
= new_used_perm
;
2198 uint64_t cumulative_shared_perms
= new_shared_perm
;
2200 assert(!q
|| !tighten_restrictions
);
2202 /* There is no reason why anyone couldn't tolerate write_unchanged */
2203 assert(new_shared_perm
& BLK_PERM_WRITE_UNCHANGED
);
2205 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
2206 if (g_slist_find(ignore_children
, c
)) {
2210 if ((new_used_perm
& c
->shared_perm
) != new_used_perm
) {
2211 char *user
= bdrv_child_user_desc(c
);
2212 char *perm_names
= bdrv_perm_names(new_used_perm
& ~c
->shared_perm
);
2214 if (tighten_restrictions
) {
2215 *tighten_restrictions
= true;
2218 error_setg(errp
, "Conflicts with use by %s as '%s', which does not "
2220 user
, c
->name
, perm_names
, bdrv_get_node_name(c
->bs
));
2226 if ((c
->perm
& new_shared_perm
) != c
->perm
) {
2227 char *user
= bdrv_child_user_desc(c
);
2228 char *perm_names
= bdrv_perm_names(c
->perm
& ~new_shared_perm
);
2230 if (tighten_restrictions
) {
2231 *tighten_restrictions
= true;
2234 error_setg(errp
, "Conflicts with use by %s as '%s', which uses "
2236 user
, c
->name
, perm_names
, bdrv_get_node_name(c
->bs
));
2242 cumulative_perms
|= c
->perm
;
2243 cumulative_shared_perms
&= c
->shared_perm
;
2246 return bdrv_check_perm(bs
, q
, cumulative_perms
, cumulative_shared_perms
,
2247 ignore_children
, tighten_restrictions
, errp
);
2250 /* Needs to be followed by a call to either bdrv_child_set_perm() or
2251 * bdrv_child_abort_perm_update(). */
2252 static int bdrv_child_check_perm(BdrvChild
*c
, BlockReopenQueue
*q
,
2253 uint64_t perm
, uint64_t shared
,
2254 GSList
*ignore_children
,
2255 bool *tighten_restrictions
, Error
**errp
)
2259 ignore_children
= g_slist_prepend(g_slist_copy(ignore_children
), c
);
2260 ret
= bdrv_check_update_perm(c
->bs
, q
, perm
, shared
, ignore_children
,
2261 tighten_restrictions
, errp
);
2262 g_slist_free(ignore_children
);
2268 if (!c
->has_backup_perm
) {
2269 c
->has_backup_perm
= true;
2270 c
->backup_perm
= c
->perm
;
2271 c
->backup_shared_perm
= c
->shared_perm
;
2274 * Note: it's OK if c->has_backup_perm was already set, as we can find the
2275 * same child twice during check_perm procedure
2279 c
->shared_perm
= shared
;
2284 static void bdrv_child_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
)
2286 uint64_t cumulative_perms
, cumulative_shared_perms
;
2288 c
->has_backup_perm
= false;
2291 c
->shared_perm
= shared
;
2293 bdrv_get_cumulative_perm(c
->bs
, &cumulative_perms
,
2294 &cumulative_shared_perms
);
2295 bdrv_set_perm(c
->bs
, cumulative_perms
, cumulative_shared_perms
);
2298 static void bdrv_child_abort_perm_update(BdrvChild
*c
)
2300 if (c
->has_backup_perm
) {
2301 c
->perm
= c
->backup_perm
;
2302 c
->shared_perm
= c
->backup_shared_perm
;
2303 c
->has_backup_perm
= false;
2306 bdrv_abort_perm_update(c
->bs
);
2309 int bdrv_child_try_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
,
2312 Error
*local_err
= NULL
;
2314 bool tighten_restrictions
;
2316 ret
= bdrv_child_check_perm(c
, NULL
, perm
, shared
, NULL
,
2317 &tighten_restrictions
, &local_err
);
2319 bdrv_child_abort_perm_update(c
);
2320 if (tighten_restrictions
) {
2321 error_propagate(errp
, local_err
);
2324 * Our caller may intend to only loosen restrictions and
2325 * does not expect this function to fail. Errors are not
2326 * fatal in such a case, so we can just hide them from our
2329 error_free(local_err
);
2335 bdrv_child_set_perm(c
, perm
, shared
);
2340 int bdrv_child_refresh_perms(BlockDriverState
*bs
, BdrvChild
*c
, Error
**errp
)
2342 uint64_t parent_perms
, parent_shared
;
2343 uint64_t perms
, shared
;
2345 bdrv_get_cumulative_perm(bs
, &parent_perms
, &parent_shared
);
2346 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, NULL
, parent_perms
, parent_shared
,
2349 return bdrv_child_try_set_perm(c
, perms
, shared
, errp
);
2352 void bdrv_filter_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2353 const BdrvChildRole
*role
,
2354 BlockReopenQueue
*reopen_queue
,
2355 uint64_t perm
, uint64_t shared
,
2356 uint64_t *nperm
, uint64_t *nshared
)
2358 *nperm
= perm
& DEFAULT_PERM_PASSTHROUGH
;
2359 *nshared
= (shared
& DEFAULT_PERM_PASSTHROUGH
) | DEFAULT_PERM_UNCHANGED
;
2362 void bdrv_format_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2363 const BdrvChildRole
*role
,
2364 BlockReopenQueue
*reopen_queue
,
2365 uint64_t perm
, uint64_t shared
,
2366 uint64_t *nperm
, uint64_t *nshared
)
2368 bool backing
= (role
== &child_backing
);
2369 assert(role
== &child_backing
|| role
== &child_file
);
2372 int flags
= bdrv_reopen_get_flags(reopen_queue
, bs
);
2374 /* Apart from the modifications below, the same permissions are
2375 * forwarded and left alone as for filters */
2376 bdrv_filter_default_perms(bs
, c
, role
, reopen_queue
, perm
, shared
,
2379 /* Format drivers may touch metadata even if the guest doesn't write */
2380 if (bdrv_is_writable_after_reopen(bs
, reopen_queue
)) {
2381 perm
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2384 /* bs->file always needs to be consistent because of the metadata. We
2385 * can never allow other users to resize or write to it. */
2386 if (!(flags
& BDRV_O_NO_IO
)) {
2387 perm
|= BLK_PERM_CONSISTENT_READ
;
2389 shared
&= ~(BLK_PERM_WRITE
| BLK_PERM_RESIZE
);
2391 /* We want consistent read from backing files if the parent needs it.
2392 * No other operations are performed on backing files. */
2393 perm
&= BLK_PERM_CONSISTENT_READ
;
2395 /* If the parent can deal with changing data, we're okay with a
2396 * writable and resizable backing file. */
2397 /* TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? */
2398 if (shared
& BLK_PERM_WRITE
) {
2399 shared
= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2404 shared
|= BLK_PERM_CONSISTENT_READ
| BLK_PERM_GRAPH_MOD
|
2405 BLK_PERM_WRITE_UNCHANGED
;
2408 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
2409 shared
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2416 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm
)
2418 static const uint64_t permissions
[] = {
2419 [BLOCK_PERMISSION_CONSISTENT_READ
] = BLK_PERM_CONSISTENT_READ
,
2420 [BLOCK_PERMISSION_WRITE
] = BLK_PERM_WRITE
,
2421 [BLOCK_PERMISSION_WRITE_UNCHANGED
] = BLK_PERM_WRITE_UNCHANGED
,
2422 [BLOCK_PERMISSION_RESIZE
] = BLK_PERM_RESIZE
,
2423 [BLOCK_PERMISSION_GRAPH_MOD
] = BLK_PERM_GRAPH_MOD
,
2426 QEMU_BUILD_BUG_ON(ARRAY_SIZE(permissions
) != BLOCK_PERMISSION__MAX
);
2427 QEMU_BUILD_BUG_ON(1UL << ARRAY_SIZE(permissions
) != BLK_PERM_ALL
+ 1);
2429 assert(qapi_perm
< BLOCK_PERMISSION__MAX
);
2431 return permissions
[qapi_perm
];
2434 static void bdrv_replace_child_noperm(BdrvChild
*child
,
2435 BlockDriverState
*new_bs
)
2437 BlockDriverState
*old_bs
= child
->bs
;
2438 int new_bs_quiesce_counter
;
2441 assert(!child
->frozen
);
2443 if (old_bs
&& new_bs
) {
2444 assert(bdrv_get_aio_context(old_bs
) == bdrv_get_aio_context(new_bs
));
2447 new_bs_quiesce_counter
= (new_bs ? new_bs
->quiesce_counter
: 0);
2448 drain_saldo
= new_bs_quiesce_counter
- child
->parent_quiesce_counter
;
2451 * If the new child node is drained but the old one was not, flush
2452 * all outstanding requests to the old child node.
2454 while (drain_saldo
> 0 && child
->role
->drained_begin
) {
2455 bdrv_parent_drained_begin_single(child
, true);
2460 /* Detach first so that the recursive drain sections coming from @child
2461 * are already gone and we only end the drain sections that came from
2463 if (child
->role
->detach
) {
2464 child
->role
->detach(child
);
2466 QLIST_REMOVE(child
, next_parent
);
2472 QLIST_INSERT_HEAD(&new_bs
->parents
, child
, next_parent
);
2475 * Detaching the old node may have led to the new node's
2476 * quiesce_counter having been decreased. Not a problem, we
2477 * just need to recognize this here and then invoke
2478 * drained_end appropriately more often.
2480 assert(new_bs
->quiesce_counter
<= new_bs_quiesce_counter
);
2481 drain_saldo
+= new_bs
->quiesce_counter
- new_bs_quiesce_counter
;
2483 /* Attach only after starting new drained sections, so that recursive
2484 * drain sections coming from @child don't get an extra .drained_begin
2486 if (child
->role
->attach
) {
2487 child
->role
->attach(child
);
2492 * If the old child node was drained but the new one is not, allow
2493 * requests to come in only after the new node has been attached.
2495 while (drain_saldo
< 0 && child
->role
->drained_end
) {
2496 bdrv_parent_drained_end_single(child
);
2502 * Updates @child to change its reference to point to @new_bs, including
2503 * checking and applying the necessary permisson updates both to the old node
2506 * NULL is passed as @new_bs for removing the reference before freeing @child.
2508 * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this
2509 * function uses bdrv_set_perm() to update the permissions according to the new
2510 * reference that @new_bs gets.
2512 static void bdrv_replace_child(BdrvChild
*child
, BlockDriverState
*new_bs
)
2514 BlockDriverState
*old_bs
= child
->bs
;
2515 uint64_t perm
, shared_perm
;
2517 bdrv_replace_child_noperm(child
, new_bs
);
2520 * Start with the new node's permissions. If @new_bs is a (direct
2521 * or indirect) child of @old_bs, we must complete the permission
2522 * update on @new_bs before we loosen the restrictions on @old_bs.
2523 * Otherwise, bdrv_check_perm() on @old_bs would re-initiate
2524 * updating the permissions of @new_bs, and thus not purely loosen
2528 bdrv_get_cumulative_perm(new_bs
, &perm
, &shared_perm
);
2529 bdrv_set_perm(new_bs
, perm
, shared_perm
);
2533 /* Update permissions for old node. This is guaranteed to succeed
2534 * because we're just taking a parent away, so we're loosening
2536 bool tighten_restrictions
;
2539 bdrv_get_cumulative_perm(old_bs
, &perm
, &shared_perm
);
2540 ret
= bdrv_check_perm(old_bs
, NULL
, perm
, shared_perm
, NULL
,
2541 &tighten_restrictions
, NULL
);
2542 assert(tighten_restrictions
== false);
2544 /* We only tried to loosen restrictions, so errors are not fatal */
2545 bdrv_abort_perm_update(old_bs
);
2547 bdrv_set_perm(old_bs
, perm
, shared_perm
);
2550 /* When the parent requiring a non-default AioContext is removed, the
2551 * node moves back to the main AioContext */
2552 bdrv_try_set_aio_context(old_bs
, qemu_get_aio_context(), NULL
);
2557 * This function steals the reference to child_bs from the caller.
2558 * That reference is later dropped by bdrv_root_unref_child().
2560 * On failure NULL is returned, errp is set and the reference to
2561 * child_bs is also dropped.
2563 * The caller must hold the AioContext lock @child_bs, but not that of @ctx
2564 * (unless @child_bs is already in @ctx).
2566 BdrvChild
*bdrv_root_attach_child(BlockDriverState
*child_bs
,
2567 const char *child_name
,
2568 const BdrvChildRole
*child_role
,
2570 uint64_t perm
, uint64_t shared_perm
,
2571 void *opaque
, Error
**errp
)
2574 Error
*local_err
= NULL
;
2577 ret
= bdrv_check_update_perm(child_bs
, NULL
, perm
, shared_perm
, NULL
, NULL
,
2580 bdrv_abort_perm_update(child_bs
);
2581 bdrv_unref(child_bs
);
2585 child
= g_new(BdrvChild
, 1);
2586 *child
= (BdrvChild
) {
2588 .name
= g_strdup(child_name
),
2591 .shared_perm
= shared_perm
,
2595 /* If the AioContexts don't match, first try to move the subtree of
2596 * child_bs into the AioContext of the new parent. If this doesn't work,
2597 * try moving the parent into the AioContext of child_bs instead. */
2598 if (bdrv_get_aio_context(child_bs
) != ctx
) {
2599 ret
= bdrv_try_set_aio_context(child_bs
, ctx
, &local_err
);
2600 if (ret
< 0 && child_role
->can_set_aio_ctx
) {
2601 GSList
*ignore
= g_slist_prepend(NULL
, child
);
2602 ctx
= bdrv_get_aio_context(child_bs
);
2603 if (child_role
->can_set_aio_ctx(child
, ctx
, &ignore
, NULL
)) {
2604 error_free(local_err
);
2606 g_slist_free(ignore
);
2607 ignore
= g_slist_prepend(NULL
, child
);
2608 child_role
->set_aio_ctx(child
, ctx
, &ignore
);
2610 g_slist_free(ignore
);
2613 error_propagate(errp
, local_err
);
2615 bdrv_abort_perm_update(child_bs
);
2620 /* This performs the matching bdrv_set_perm() for the above check. */
2621 bdrv_replace_child(child
, child_bs
);
2627 * This function transfers the reference to child_bs from the caller
2628 * to parent_bs. That reference is later dropped by parent_bs on
2629 * bdrv_close() or if someone calls bdrv_unref_child().
2631 * On failure NULL is returned, errp is set and the reference to
2632 * child_bs is also dropped.
2634 * If @parent_bs and @child_bs are in different AioContexts, the caller must
2635 * hold the AioContext lock for @child_bs, but not for @parent_bs.
2637 BdrvChild
*bdrv_attach_child(BlockDriverState
*parent_bs
,
2638 BlockDriverState
*child_bs
,
2639 const char *child_name
,
2640 const BdrvChildRole
*child_role
,
2644 uint64_t perm
, shared_perm
;
2646 bdrv_get_cumulative_perm(parent_bs
, &perm
, &shared_perm
);
2648 assert(parent_bs
->drv
);
2649 bdrv_child_perm(parent_bs
, child_bs
, NULL
, child_role
, NULL
,
2650 perm
, shared_perm
, &perm
, &shared_perm
);
2652 child
= bdrv_root_attach_child(child_bs
, child_name
, child_role
,
2653 bdrv_get_aio_context(parent_bs
),
2654 perm
, shared_perm
, parent_bs
, errp
);
2655 if (child
== NULL
) {
2659 QLIST_INSERT_HEAD(&parent_bs
->children
, child
, next
);
2663 static void bdrv_detach_child(BdrvChild
*child
)
2665 QLIST_SAFE_REMOVE(child
, next
);
2667 bdrv_replace_child(child
, NULL
);
2669 g_free(child
->name
);
2673 void bdrv_root_unref_child(BdrvChild
*child
)
2675 BlockDriverState
*child_bs
;
2677 child_bs
= child
->bs
;
2678 bdrv_detach_child(child
);
2679 bdrv_unref(child_bs
);
2683 * Clear all inherits_from pointers from children and grandchildren of
2684 * @root that point to @root, where necessary.
2686 static void bdrv_unset_inherits_from(BlockDriverState
*root
, BdrvChild
*child
)
2690 if (child
->bs
->inherits_from
== root
) {
2692 * Remove inherits_from only when the last reference between root and
2693 * child->bs goes away.
2695 QLIST_FOREACH(c
, &root
->children
, next
) {
2696 if (c
!= child
&& c
->bs
== child
->bs
) {
2701 child
->bs
->inherits_from
= NULL
;
2705 QLIST_FOREACH(c
, &child
->bs
->children
, next
) {
2706 bdrv_unset_inherits_from(root
, c
);
2710 void bdrv_unref_child(BlockDriverState
*parent
, BdrvChild
*child
)
2712 if (child
== NULL
) {
2716 bdrv_unset_inherits_from(parent
, child
);
2717 bdrv_root_unref_child(child
);
2721 static void bdrv_parent_cb_change_media(BlockDriverState
*bs
, bool load
)
2724 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
2725 if (c
->role
->change_media
) {
2726 c
->role
->change_media(c
, load
);
2731 /* Return true if you can reach parent going through child->inherits_from
2732 * recursively. If parent or child are NULL, return false */
2733 static bool bdrv_inherits_from_recursive(BlockDriverState
*child
,
2734 BlockDriverState
*parent
)
2736 while (child
&& child
!= parent
) {
2737 child
= child
->inherits_from
;
2740 return child
!= NULL
;
2744 * Sets the backing file link of a BDS. A new reference is created; callers
2745 * which don't need their own reference any more must call bdrv_unref().
2747 void bdrv_set_backing_hd(BlockDriverState
*bs
, BlockDriverState
*backing_hd
,
2750 bool update_inherits_from
= bdrv_chain_contains(bs
, backing_hd
) &&
2751 bdrv_inherits_from_recursive(backing_hd
, bs
);
2753 if (bdrv_is_backing_chain_frozen(bs
, backing_bs(bs
), errp
)) {
2758 bdrv_ref(backing_hd
);
2762 bdrv_unref_child(bs
, bs
->backing
);
2770 bs
->backing
= bdrv_attach_child(bs
, backing_hd
, "backing", &child_backing
,
2772 /* If backing_hd was already part of bs's backing chain, and
2773 * inherits_from pointed recursively to bs then let's update it to
2774 * point directly to bs (else it will become NULL). */
2775 if (bs
->backing
&& update_inherits_from
) {
2776 backing_hd
->inherits_from
= bs
;
2780 bdrv_refresh_limits(bs
, NULL
);
2784 * Opens the backing file for a BlockDriverState if not yet open
2786 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
2787 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2788 * itself, all options starting with "${bdref_key}." are considered part of the
2791 * TODO Can this be unified with bdrv_open_image()?
2793 int bdrv_open_backing_file(BlockDriverState
*bs
, QDict
*parent_options
,
2794 const char *bdref_key
, Error
**errp
)
2796 char *backing_filename
= NULL
;
2797 char *bdref_key_dot
;
2798 const char *reference
= NULL
;
2800 bool implicit_backing
= false;
2801 BlockDriverState
*backing_hd
;
2803 QDict
*tmp_parent_options
= NULL
;
2804 Error
*local_err
= NULL
;
2806 if (bs
->backing
!= NULL
) {
2810 /* NULL means an empty set of options */
2811 if (parent_options
== NULL
) {
2812 tmp_parent_options
= qdict_new();
2813 parent_options
= tmp_parent_options
;
2816 bs
->open_flags
&= ~BDRV_O_NO_BACKING
;
2818 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
2819 qdict_extract_subqdict(parent_options
, &options
, bdref_key_dot
);
2820 g_free(bdref_key_dot
);
2823 * Caution: while qdict_get_try_str() is fine, getting non-string
2824 * types would require more care. When @parent_options come from
2825 * -blockdev or blockdev_add, its members are typed according to
2826 * the QAPI schema, but when they come from -drive, they're all
2829 reference
= qdict_get_try_str(parent_options
, bdref_key
);
2830 if (reference
|| qdict_haskey(options
, "file.filename")) {
2831 /* keep backing_filename NULL */
2832 } else if (bs
->backing_file
[0] == '\0' && qdict_size(options
) == 0) {
2833 qobject_unref(options
);
2836 if (qdict_size(options
) == 0) {
2837 /* If the user specifies options that do not modify the
2838 * backing file's behavior, we might still consider it the
2839 * implicit backing file. But it's easier this way, and
2840 * just specifying some of the backing BDS's options is
2841 * only possible with -drive anyway (otherwise the QAPI
2842 * schema forces the user to specify everything). */
2843 implicit_backing
= !strcmp(bs
->auto_backing_file
, bs
->backing_file
);
2846 backing_filename
= bdrv_get_full_backing_filename(bs
, &local_err
);
2849 error_propagate(errp
, local_err
);
2850 qobject_unref(options
);
2855 if (!bs
->drv
|| !bs
->drv
->supports_backing
) {
2857 error_setg(errp
, "Driver doesn't support backing files");
2858 qobject_unref(options
);
2863 bs
->backing_format
[0] != '\0' && !qdict_haskey(options
, "driver")) {
2864 qdict_put_str(options
, "driver", bs
->backing_format
);
2867 backing_hd
= bdrv_open_inherit(backing_filename
, reference
, options
, 0, bs
,
2868 &child_backing
, errp
);
2870 bs
->open_flags
|= BDRV_O_NO_BACKING
;
2871 error_prepend(errp
, "Could not open backing file: ");
2876 if (implicit_backing
) {
2877 bdrv_refresh_filename(backing_hd
);
2878 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
2879 backing_hd
->filename
);
2882 /* Hook up the backing file link; drop our reference, bs owns the
2883 * backing_hd reference now */
2884 bdrv_set_backing_hd(bs
, backing_hd
, &local_err
);
2885 bdrv_unref(backing_hd
);
2887 error_propagate(errp
, local_err
);
2892 qdict_del(parent_options
, bdref_key
);
2895 g_free(backing_filename
);
2896 qobject_unref(tmp_parent_options
);
2900 static BlockDriverState
*
2901 bdrv_open_child_bs(const char *filename
, QDict
*options
, const char *bdref_key
,
2902 BlockDriverState
*parent
, const BdrvChildRole
*child_role
,
2903 bool allow_none
, Error
**errp
)
2905 BlockDriverState
*bs
= NULL
;
2906 QDict
*image_options
;
2907 char *bdref_key_dot
;
2908 const char *reference
;
2910 assert(child_role
!= NULL
);
2912 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
2913 qdict_extract_subqdict(options
, &image_options
, bdref_key_dot
);
2914 g_free(bdref_key_dot
);
2917 * Caution: while qdict_get_try_str() is fine, getting non-string
2918 * types would require more care. When @options come from
2919 * -blockdev or blockdev_add, its members are typed according to
2920 * the QAPI schema, but when they come from -drive, they're all
2923 reference
= qdict_get_try_str(options
, bdref_key
);
2924 if (!filename
&& !reference
&& !qdict_size(image_options
)) {
2926 error_setg(errp
, "A block device must be specified for \"%s\"",
2929 qobject_unref(image_options
);
2933 bs
= bdrv_open_inherit(filename
, reference
, image_options
, 0,
2934 parent
, child_role
, errp
);
2940 qdict_del(options
, bdref_key
);
2945 * Opens a disk image whose options are given as BlockdevRef in another block
2948 * If allow_none is true, no image will be opened if filename is false and no
2949 * BlockdevRef is given. NULL will be returned, but errp remains unset.
2951 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
2952 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2953 * itself, all options starting with "${bdref_key}." are considered part of the
2956 * The BlockdevRef will be removed from the options QDict.
2958 BdrvChild
*bdrv_open_child(const char *filename
,
2959 QDict
*options
, const char *bdref_key
,
2960 BlockDriverState
*parent
,
2961 const BdrvChildRole
*child_role
,
2962 bool allow_none
, Error
**errp
)
2964 BlockDriverState
*bs
;
2966 bs
= bdrv_open_child_bs(filename
, options
, bdref_key
, parent
, child_role
,
2972 return bdrv_attach_child(parent
, bs
, bdref_key
, child_role
, errp
);
2975 /* TODO Future callers may need to specify parent/child_role in order for
2976 * option inheritance to work. Existing callers use it for the root node. */
2977 BlockDriverState
*bdrv_open_blockdev_ref(BlockdevRef
*ref
, Error
**errp
)
2979 BlockDriverState
*bs
= NULL
;
2980 Error
*local_err
= NULL
;
2981 QObject
*obj
= NULL
;
2982 QDict
*qdict
= NULL
;
2983 const char *reference
= NULL
;
2986 if (ref
->type
== QTYPE_QSTRING
) {
2987 reference
= ref
->u
.reference
;
2989 BlockdevOptions
*options
= &ref
->u
.definition
;
2990 assert(ref
->type
== QTYPE_QDICT
);
2992 v
= qobject_output_visitor_new(&obj
);
2993 visit_type_BlockdevOptions(v
, NULL
, &options
, &local_err
);
2995 error_propagate(errp
, local_err
);
2998 visit_complete(v
, &obj
);
3000 qdict
= qobject_to(QDict
, obj
);
3001 qdict_flatten(qdict
);
3003 /* bdrv_open_inherit() defaults to the values in bdrv_flags (for
3004 * compatibility with other callers) rather than what we want as the
3005 * real defaults. Apply the defaults here instead. */
3006 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_DIRECT
, "off");
3007 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_NO_FLUSH
, "off");
3008 qdict_set_default_str(qdict
, BDRV_OPT_READ_ONLY
, "off");
3009 qdict_set_default_str(qdict
, BDRV_OPT_AUTO_READ_ONLY
, "off");
3013 bs
= bdrv_open_inherit(NULL
, reference
, qdict
, 0, NULL
, NULL
, errp
);
3022 static BlockDriverState
*bdrv_append_temp_snapshot(BlockDriverState
*bs
,
3024 QDict
*snapshot_options
,
3027 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
3028 char *tmp_filename
= g_malloc0(PATH_MAX
+ 1);
3030 QemuOpts
*opts
= NULL
;
3031 BlockDriverState
*bs_snapshot
= NULL
;
3032 Error
*local_err
= NULL
;
3035 /* if snapshot, we create a temporary backing file and open it
3036 instead of opening 'filename' directly */
3038 /* Get the required size from the image */
3039 total_size
= bdrv_getlength(bs
);
3040 if (total_size
< 0) {
3041 error_setg_errno(errp
, -total_size
, "Could not get image size");
3045 /* Create the temporary image */
3046 ret
= get_tmp_filename(tmp_filename
, PATH_MAX
+ 1);
3048 error_setg_errno(errp
, -ret
, "Could not get temporary filename");
3052 opts
= qemu_opts_create(bdrv_qcow2
.create_opts
, NULL
, 0,
3054 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, total_size
, &error_abort
);
3055 ret
= bdrv_create(&bdrv_qcow2
, tmp_filename
, opts
, errp
);
3056 qemu_opts_del(opts
);
3058 error_prepend(errp
, "Could not create temporary overlay '%s': ",
3063 /* Prepare options QDict for the temporary file */
3064 qdict_put_str(snapshot_options
, "file.driver", "file");
3065 qdict_put_str(snapshot_options
, "file.filename", tmp_filename
);
3066 qdict_put_str(snapshot_options
, "driver", "qcow2");
3068 bs_snapshot
= bdrv_open(NULL
, NULL
, snapshot_options
, flags
, errp
);
3069 snapshot_options
= NULL
;
3074 /* bdrv_append() consumes a strong reference to bs_snapshot
3075 * (i.e. it will call bdrv_unref() on it) even on error, so in
3076 * order to be able to return one, we have to increase
3077 * bs_snapshot's refcount here */
3078 bdrv_ref(bs_snapshot
);
3079 bdrv_append(bs_snapshot
, bs
, &local_err
);
3081 error_propagate(errp
, local_err
);
3087 qobject_unref(snapshot_options
);
3088 g_free(tmp_filename
);
3093 * Opens a disk image (raw, qcow2, vmdk, ...)
3095 * options is a QDict of options to pass to the block drivers, or NULL for an
3096 * empty set of options. The reference to the QDict belongs to the block layer
3097 * after the call (even on failure), so if the caller intends to reuse the
3098 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
3100 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
3101 * If it is not NULL, the referenced BDS will be reused.
3103 * The reference parameter may be used to specify an existing block device which
3104 * should be opened. If specified, neither options nor a filename may be given,
3105 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
3107 static BlockDriverState
*bdrv_open_inherit(const char *filename
,
3108 const char *reference
,
3109 QDict
*options
, int flags
,
3110 BlockDriverState
*parent
,
3111 const BdrvChildRole
*child_role
,
3115 BlockBackend
*file
= NULL
;
3116 BlockDriverState
*bs
;
3117 BlockDriver
*drv
= NULL
;
3119 const char *drvname
;
3120 const char *backing
;
3121 Error
*local_err
= NULL
;
3122 QDict
*snapshot_options
= NULL
;
3123 int snapshot_flags
= 0;
3125 assert(!child_role
|| !flags
);
3126 assert(!child_role
== !parent
);
3129 bool options_non_empty
= options ?
qdict_size(options
) : false;
3130 qobject_unref(options
);
3132 if (filename
|| options_non_empty
) {
3133 error_setg(errp
, "Cannot reference an existing block device with "
3134 "additional options or a new filename");
3138 bs
= bdrv_lookup_bs(reference
, reference
, errp
);
3149 /* NULL means an empty set of options */
3150 if (options
== NULL
) {
3151 options
= qdict_new();
3154 /* json: syntax counts as explicit options, as if in the QDict */
3155 parse_json_protocol(options
, &filename
, &local_err
);
3160 bs
->explicit_options
= qdict_clone_shallow(options
);
3163 bs
->inherits_from
= parent
;
3164 child_role
->inherit_options(&flags
, options
,
3165 parent
->open_flags
, parent
->options
);
3168 ret
= bdrv_fill_options(&options
, filename
, &flags
, &local_err
);
3174 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
3175 * Caution: getting a boolean member of @options requires care.
3176 * When @options come from -blockdev or blockdev_add, members are
3177 * typed according to the QAPI schema, but when they come from
3178 * -drive, they're all QString.
3180 if (g_strcmp0(qdict_get_try_str(options
, BDRV_OPT_READ_ONLY
), "on") &&
3181 !qdict_get_try_bool(options
, BDRV_OPT_READ_ONLY
, false)) {
3182 flags
|= (BDRV_O_RDWR
| BDRV_O_ALLOW_RDWR
);
3184 flags
&= ~BDRV_O_RDWR
;
3187 if (flags
& BDRV_O_SNAPSHOT
) {
3188 snapshot_options
= qdict_new();
3189 bdrv_temp_snapshot_options(&snapshot_flags
, snapshot_options
,
3191 /* Let bdrv_backing_options() override "read-only" */
3192 qdict_del(options
, BDRV_OPT_READ_ONLY
);
3193 bdrv_backing_options(&flags
, options
, flags
, options
);
3196 bs
->open_flags
= flags
;
3197 bs
->options
= options
;
3198 options
= qdict_clone_shallow(options
);
3200 /* Find the right image format driver */
3201 /* See cautionary note on accessing @options above */
3202 drvname
= qdict_get_try_str(options
, "driver");
3204 drv
= bdrv_find_format(drvname
);
3206 error_setg(errp
, "Unknown driver: '%s'", drvname
);
3211 assert(drvname
|| !(flags
& BDRV_O_PROTOCOL
));
3213 /* See cautionary note on accessing @options above */
3214 backing
= qdict_get_try_str(options
, "backing");
3215 if (qobject_to(QNull
, qdict_get(options
, "backing")) != NULL
||
3216 (backing
&& *backing
== '\0'))
3219 warn_report("Use of \"backing\": \"\" is deprecated; "
3220 "use \"backing\": null instead");
3222 flags
|= BDRV_O_NO_BACKING
;
3223 qdict_del(bs
->explicit_options
, "backing");
3224 qdict_del(bs
->options
, "backing");
3225 qdict_del(options
, "backing");
3228 /* Open image file without format layer. This BlockBackend is only used for
3229 * probing, the block drivers will do their own bdrv_open_child() for the
3230 * same BDS, which is why we put the node name back into options. */
3231 if ((flags
& BDRV_O_PROTOCOL
) == 0) {
3232 BlockDriverState
*file_bs
;
3234 file_bs
= bdrv_open_child_bs(filename
, options
, "file", bs
,
3235 &child_file
, true, &local_err
);
3239 if (file_bs
!= NULL
) {
3240 /* Not requesting BLK_PERM_CONSISTENT_READ because we're only
3241 * looking at the header to guess the image format. This works even
3242 * in cases where a guest would not see a consistent state. */
3243 file
= blk_new(bdrv_get_aio_context(file_bs
), 0, BLK_PERM_ALL
);
3244 blk_insert_bs(file
, file_bs
, &local_err
);
3245 bdrv_unref(file_bs
);
3250 qdict_put_str(options
, "file", bdrv_get_node_name(file_bs
));
3254 /* Image format probing */
3257 ret
= find_image_format(file
, filename
, &drv
, &local_err
);
3262 * This option update would logically belong in bdrv_fill_options(),
3263 * but we first need to open bs->file for the probing to work, while
3264 * opening bs->file already requires the (mostly) final set of options
3265 * so that cache mode etc. can be inherited.
3267 * Adding the driver later is somewhat ugly, but it's not an option
3268 * that would ever be inherited, so it's correct. We just need to make
3269 * sure to update both bs->options (which has the full effective
3270 * options for bs) and options (which has file.* already removed).
3272 qdict_put_str(bs
->options
, "driver", drv
->format_name
);
3273 qdict_put_str(options
, "driver", drv
->format_name
);
3275 error_setg(errp
, "Must specify either driver or file");
3279 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
3280 assert(!!(flags
& BDRV_O_PROTOCOL
) == !!drv
->bdrv_file_open
);
3281 /* file must be NULL if a protocol BDS is about to be created
3282 * (the inverse results in an error message from bdrv_open_common()) */
3283 assert(!(flags
& BDRV_O_PROTOCOL
) || !file
);
3285 /* Open the image */
3286 ret
= bdrv_open_common(bs
, file
, options
, &local_err
);
3296 /* If there is a backing file, use it */
3297 if ((flags
& BDRV_O_NO_BACKING
) == 0) {
3298 ret
= bdrv_open_backing_file(bs
, options
, "backing", &local_err
);
3300 goto close_and_fail
;
3304 /* Remove all children options and references
3305 * from bs->options and bs->explicit_options */
3306 QLIST_FOREACH(child
, &bs
->children
, next
) {
3307 char *child_key_dot
;
3308 child_key_dot
= g_strdup_printf("%s.", child
->name
);
3309 qdict_extract_subqdict(bs
->explicit_options
, NULL
, child_key_dot
);
3310 qdict_extract_subqdict(bs
->options
, NULL
, child_key_dot
);
3311 qdict_del(bs
->explicit_options
, child
->name
);
3312 qdict_del(bs
->options
, child
->name
);
3313 g_free(child_key_dot
);
3316 /* Check if any unknown options were used */
3317 if (qdict_size(options
) != 0) {
3318 const QDictEntry
*entry
= qdict_first(options
);
3319 if (flags
& BDRV_O_PROTOCOL
) {
3320 error_setg(errp
, "Block protocol '%s' doesn't support the option "
3321 "'%s'", drv
->format_name
, entry
->key
);
3324 "Block format '%s' does not support the option '%s'",
3325 drv
->format_name
, entry
->key
);
3328 goto close_and_fail
;
3331 bdrv_parent_cb_change_media(bs
, true);
3333 qobject_unref(options
);
3336 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
3337 * temporary snapshot afterwards. */
3338 if (snapshot_flags
) {
3339 BlockDriverState
*snapshot_bs
;
3340 snapshot_bs
= bdrv_append_temp_snapshot(bs
, snapshot_flags
,
3341 snapshot_options
, &local_err
);
3342 snapshot_options
= NULL
;
3344 goto close_and_fail
;
3346 /* We are not going to return bs but the overlay on top of it
3347 * (snapshot_bs); thus, we have to drop the strong reference to bs
3348 * (which we obtained by calling bdrv_new()). bs will not be deleted,
3349 * though, because the overlay still has a reference to it. */
3358 qobject_unref(snapshot_options
);
3359 qobject_unref(bs
->explicit_options
);
3360 qobject_unref(bs
->options
);
3361 qobject_unref(options
);
3363 bs
->explicit_options
= NULL
;
3365 error_propagate(errp
, local_err
);
3370 qobject_unref(snapshot_options
);
3371 qobject_unref(options
);
3372 error_propagate(errp
, local_err
);
3376 BlockDriverState
*bdrv_open(const char *filename
, const char *reference
,
3377 QDict
*options
, int flags
, Error
**errp
)
3379 return bdrv_open_inherit(filename
, reference
, options
, flags
, NULL
,
3383 /* Return true if the NULL-terminated @list contains @str */
3384 static bool is_str_in_list(const char *str
, const char *const *list
)
3388 for (i
= 0; list
[i
] != NULL
; i
++) {
3389 if (!strcmp(str
, list
[i
])) {
3398 * Check that every option set in @bs->options is also set in
3401 * Options listed in the common_options list and in
3402 * @bs->drv->mutable_opts are skipped.
3404 * Return 0 on success, otherwise return -EINVAL and set @errp.
3406 static int bdrv_reset_options_allowed(BlockDriverState
*bs
,
3407 const QDict
*new_opts
, Error
**errp
)
3409 const QDictEntry
*e
;
3410 /* These options are common to all block drivers and are handled
3411 * in bdrv_reopen_prepare() so they can be left out of @new_opts */
3412 const char *const common_options
[] = {
3413 "node-name", "discard", "cache.direct", "cache.no-flush",
3414 "read-only", "auto-read-only", "detect-zeroes", NULL
3417 for (e
= qdict_first(bs
->options
); e
; e
= qdict_next(bs
->options
, e
)) {
3418 if (!qdict_haskey(new_opts
, e
->key
) &&
3419 !is_str_in_list(e
->key
, common_options
) &&
3420 !is_str_in_list(e
->key
, bs
->drv
->mutable_opts
)) {
3421 error_setg(errp
, "Option '%s' cannot be reset "
3422 "to its default value", e
->key
);
3431 * Returns true if @child can be reached recursively from @bs
3433 static bool bdrv_recurse_has_child(BlockDriverState
*bs
,
3434 BlockDriverState
*child
)
3442 QLIST_FOREACH(c
, &bs
->children
, next
) {
3443 if (bdrv_recurse_has_child(c
->bs
, child
)) {
3452 * Adds a BlockDriverState to a simple queue for an atomic, transactional
3453 * reopen of multiple devices.
3455 * bs_queue can either be an existing BlockReopenQueue that has had QTAILQ_INIT
3456 * already performed, or alternatively may be NULL a new BlockReopenQueue will
3457 * be created and initialized. This newly created BlockReopenQueue should be
3458 * passed back in for subsequent calls that are intended to be of the same
3461 * bs is the BlockDriverState to add to the reopen queue.
3463 * options contains the changed options for the associated bs
3464 * (the BlockReopenQueue takes ownership)
3466 * flags contains the open flags for the associated bs
3468 * returns a pointer to bs_queue, which is either the newly allocated
3469 * bs_queue, or the existing bs_queue being used.
3471 * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple().
3473 static BlockReopenQueue
*bdrv_reopen_queue_child(BlockReopenQueue
*bs_queue
,
3474 BlockDriverState
*bs
,
3476 const BdrvChildRole
*role
,
3477 QDict
*parent_options
,
3483 BlockReopenQueueEntry
*bs_entry
;
3485 QDict
*old_options
, *explicit_options
, *options_copy
;
3489 /* Make sure that the caller remembered to use a drained section. This is
3490 * important to avoid graph changes between the recursive queuing here and
3491 * bdrv_reopen_multiple(). */
3492 assert(bs
->quiesce_counter
> 0);
3494 if (bs_queue
== NULL
) {
3495 bs_queue
= g_new0(BlockReopenQueue
, 1);
3496 QTAILQ_INIT(bs_queue
);
3500 options
= qdict_new();
3503 /* Check if this BlockDriverState is already in the queue */
3504 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
3505 if (bs
== bs_entry
->state
.bs
) {
3511 * Precedence of options:
3512 * 1. Explicitly passed in options (highest)
3513 * 2. Retained from explicitly set options of bs
3514 * 3. Inherited from parent node
3515 * 4. Retained from effective options of bs
3518 /* Old explicitly set values (don't overwrite by inherited value) */
3519 if (bs_entry
|| keep_old_opts
) {
3520 old_options
= qdict_clone_shallow(bs_entry ?
3521 bs_entry
->state
.explicit_options
:
3522 bs
->explicit_options
);
3523 bdrv_join_options(bs
, options
, old_options
);
3524 qobject_unref(old_options
);
3527 explicit_options
= qdict_clone_shallow(options
);
3529 /* Inherit from parent node */
3530 if (parent_options
) {
3532 role
->inherit_options(&flags
, options
, parent_flags
, parent_options
);
3534 flags
= bdrv_get_flags(bs
);
3537 if (keep_old_opts
) {
3538 /* Old values are used for options that aren't set yet */
3539 old_options
= qdict_clone_shallow(bs
->options
);
3540 bdrv_join_options(bs
, options
, old_options
);
3541 qobject_unref(old_options
);
3544 /* We have the final set of options so let's update the flags */
3545 options_copy
= qdict_clone_shallow(options
);
3546 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
3547 qemu_opts_absorb_qdict(opts
, options_copy
, NULL
);
3548 update_flags_from_options(&flags
, opts
);
3549 qemu_opts_del(opts
);
3550 qobject_unref(options_copy
);
3552 /* bdrv_open_inherit() sets and clears some additional flags internally */
3553 flags
&= ~BDRV_O_PROTOCOL
;