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/fuse.h"
30 #include "block/nbd.h"
31 #include "block/qdict.h"
32 #include "qemu/error-report.h"
33 #include "block/module_block.h"
34 #include "qemu/main-loop.h"
35 #include "qemu/module.h"
36 #include "qapi/error.h"
37 #include "qapi/qmp/qdict.h"
38 #include "qapi/qmp/qjson.h"
39 #include "qapi/qmp/qnull.h"
40 #include "qapi/qmp/qstring.h"
41 #include "qapi/qobject-output-visitor.h"
42 #include "qapi/qapi-visit-block-core.h"
43 #include "sysemu/block-backend.h"
44 #include "sysemu/sysemu.h"
45 #include "qemu/notify.h"
46 #include "qemu/option.h"
47 #include "qemu/coroutine.h"
48 #include "block/qapi.h"
49 #include "qemu/timer.h"
50 #include "qemu/cutils.h"
52 #include "block/coroutines.h"
55 #include <sys/ioctl.h>
56 #include <sys/queue.h>
66 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
68 static QTAILQ_HEAD(, BlockDriverState
) graph_bdrv_states
=
69 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states
);
71 static QTAILQ_HEAD(, BlockDriverState
) all_bdrv_states
=
72 QTAILQ_HEAD_INITIALIZER(all_bdrv_states
);
74 static QLIST_HEAD(, BlockDriver
) bdrv_drivers
=
75 QLIST_HEAD_INITIALIZER(bdrv_drivers
);
77 static BlockDriverState
*bdrv_open_inherit(const char *filename
,
78 const char *reference
,
79 QDict
*options
, int flags
,
80 BlockDriverState
*parent
,
81 const BdrvChildClass
*child_class
,
82 BdrvChildRole child_role
,
85 /* If non-zero, use only whitelisted block drivers */
86 static int use_bdrv_whitelist
;
89 static int is_windows_drive_prefix(const char *filename
)
91 return (((filename
[0] >= 'a' && filename
[0] <= 'z') ||
92 (filename
[0] >= 'A' && filename
[0] <= 'Z')) &&
96 int is_windows_drive(const char *filename
)
98 if (is_windows_drive_prefix(filename
) &&
101 if (strstart(filename
, "\\\\.\\", NULL
) ||
102 strstart(filename
, "//./", NULL
))
108 size_t bdrv_opt_mem_align(BlockDriverState
*bs
)
110 if (!bs
|| !bs
->drv
) {
111 /* page size or 4k (hdd sector size) should be on the safe side */
112 return MAX(4096, qemu_real_host_page_size
);
115 return bs
->bl
.opt_mem_alignment
;
118 size_t bdrv_min_mem_align(BlockDriverState
*bs
)
120 if (!bs
|| !bs
->drv
) {
121 /* page size or 4k (hdd sector size) should be on the safe side */
122 return MAX(4096, qemu_real_host_page_size
);
125 return bs
->bl
.min_mem_alignment
;
128 /* check if the path starts with "<protocol>:" */
129 int path_has_protocol(const char *path
)
134 if (is_windows_drive(path
) ||
135 is_windows_drive_prefix(path
)) {
138 p
= path
+ strcspn(path
, ":/\\");
140 p
= path
+ strcspn(path
, ":/");
146 int path_is_absolute(const char *path
)
149 /* specific case for names like: "\\.\d:" */
150 if (is_windows_drive(path
) || is_windows_drive_prefix(path
)) {
153 return (*path
== '/' || *path
== '\\');
155 return (*path
== '/');
159 /* if filename is absolute, just return its duplicate. Otherwise, build a
160 path to it by considering it is relative to base_path. URL are
162 char *path_combine(const char *base_path
, const char *filename
)
164 const char *protocol_stripped
= NULL
;
169 if (path_is_absolute(filename
)) {
170 return g_strdup(filename
);
173 if (path_has_protocol(base_path
)) {
174 protocol_stripped
= strchr(base_path
, ':');
175 if (protocol_stripped
) {
179 p
= protocol_stripped
?: base_path
;
181 p1
= strrchr(base_path
, '/');
185 p2
= strrchr(base_path
, '\\');
186 if (!p1
|| p2
> p1
) {
201 result
= g_malloc(len
+ strlen(filename
) + 1);
202 memcpy(result
, base_path
, len
);
203 strcpy(result
+ len
, filename
);
209 * Helper function for bdrv_parse_filename() implementations to remove optional
210 * protocol prefixes (especially "file:") from a filename and for putting the
211 * stripped filename into the options QDict if there is such a prefix.
213 void bdrv_parse_filename_strip_prefix(const char *filename
, const char *prefix
,
216 if (strstart(filename
, prefix
, &filename
)) {
217 /* Stripping the explicit protocol prefix may result in a protocol
218 * prefix being (wrongly) detected (if the filename contains a colon) */
219 if (path_has_protocol(filename
)) {
220 GString
*fat_filename
;
222 /* This means there is some colon before the first slash; therefore,
223 * this cannot be an absolute path */
224 assert(!path_is_absolute(filename
));
226 /* And we can thus fix the protocol detection issue by prefixing it
228 fat_filename
= g_string_new("./");
229 g_string_append(fat_filename
, filename
);
231 assert(!path_has_protocol(fat_filename
->str
));
233 qdict_put(options
, "filename",
234 qstring_from_gstring(fat_filename
));
236 /* If no protocol prefix was detected, we can use the shortened
238 qdict_put_str(options
, "filename", filename
);
244 /* Returns whether the image file is opened as read-only. Note that this can
245 * return false and writing to the image file is still not possible because the
246 * image is inactivated. */
247 bool bdrv_is_read_only(BlockDriverState
*bs
)
249 return bs
->read_only
;
252 int bdrv_can_set_read_only(BlockDriverState
*bs
, bool read_only
,
253 bool ignore_allow_rdw
, Error
**errp
)
255 /* Do not set read_only if copy_on_read is enabled */
256 if (bs
->copy_on_read
&& read_only
) {
257 error_setg(errp
, "Can't set node '%s' to r/o with copy-on-read enabled",
258 bdrv_get_device_or_node_name(bs
));
262 /* Do not clear read_only if it is prohibited */
263 if (!read_only
&& !(bs
->open_flags
& BDRV_O_ALLOW_RDWR
) &&
266 error_setg(errp
, "Node '%s' is read only",
267 bdrv_get_device_or_node_name(bs
));
275 * Called by a driver that can only provide a read-only image.
277 * Returns 0 if the node is already read-only or it could switch the node to
278 * read-only because BDRV_O_AUTO_RDONLY is set.
280 * Returns -EACCES if the node is read-write and BDRV_O_AUTO_RDONLY is not set
281 * or bdrv_can_set_read_only() forbids making the node read-only. If @errmsg
282 * is not NULL, it is used as the error message for the Error object.
284 int bdrv_apply_auto_read_only(BlockDriverState
*bs
, const char *errmsg
,
289 if (!(bs
->open_flags
& BDRV_O_RDWR
)) {
292 if (!(bs
->open_flags
& BDRV_O_AUTO_RDONLY
)) {
296 ret
= bdrv_can_set_read_only(bs
, true, false, NULL
);
301 bs
->read_only
= true;
302 bs
->open_flags
&= ~BDRV_O_RDWR
;
307 error_setg(errp
, "%s", errmsg
?: "Image is read-only");
312 * If @backing is empty, this function returns NULL without setting
313 * @errp. In all other cases, NULL will only be returned with @errp
316 * Therefore, a return value of NULL without @errp set means that
317 * there is no backing file; if @errp is set, there is one but its
318 * absolute filename cannot be generated.
320 char *bdrv_get_full_backing_filename_from_filename(const char *backed
,
324 if (backing
[0] == '\0') {
326 } else if (path_has_protocol(backing
) || path_is_absolute(backing
)) {
327 return g_strdup(backing
);
328 } else if (backed
[0] == '\0' || strstart(backed
, "json:", NULL
)) {
329 error_setg(errp
, "Cannot use relative backing file names for '%s'",
333 return path_combine(backed
, backing
);
338 * If @filename is empty or NULL, this function returns NULL without
339 * setting @errp. In all other cases, NULL will only be returned with
342 static char *bdrv_make_absolute_filename(BlockDriverState
*relative_to
,
343 const char *filename
, Error
**errp
)
345 char *dir
, *full_name
;
347 if (!filename
|| filename
[0] == '\0') {
349 } else if (path_has_protocol(filename
) || path_is_absolute(filename
)) {
350 return g_strdup(filename
);
353 dir
= bdrv_dirname(relative_to
, errp
);
358 full_name
= g_strconcat(dir
, filename
, NULL
);
363 char *bdrv_get_full_backing_filename(BlockDriverState
*bs
, Error
**errp
)
365 return bdrv_make_absolute_filename(bs
, bs
->backing_file
, errp
);
368 void bdrv_register(BlockDriver
*bdrv
)
370 assert(bdrv
->format_name
);
371 QLIST_INSERT_HEAD(&bdrv_drivers
, bdrv
, list
);
374 BlockDriverState
*bdrv_new(void)
376 BlockDriverState
*bs
;
379 bs
= g_new0(BlockDriverState
, 1);
380 QLIST_INIT(&bs
->dirty_bitmaps
);
381 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
382 QLIST_INIT(&bs
->op_blockers
[i
]);
384 notifier_with_return_list_init(&bs
->before_write_notifiers
);
385 qemu_co_mutex_init(&bs
->reqs_lock
);
386 qemu_mutex_init(&bs
->dirty_bitmap_mutex
);
388 bs
->aio_context
= qemu_get_aio_context();
390 qemu_co_queue_init(&bs
->flush_queue
);
392 for (i
= 0; i
< bdrv_drain_all_count
; i
++) {
393 bdrv_drained_begin(bs
);
396 QTAILQ_INSERT_TAIL(&all_bdrv_states
, bs
, bs_list
);
401 static BlockDriver
*bdrv_do_find_format(const char *format_name
)
405 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
406 if (!strcmp(drv1
->format_name
, format_name
)) {
414 BlockDriver
*bdrv_find_format(const char *format_name
)
419 drv1
= bdrv_do_find_format(format_name
);
424 /* The driver isn't registered, maybe we need to load a module */
425 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
426 if (!strcmp(block_driver_modules
[i
].format_name
, format_name
)) {
427 block_module_load_one(block_driver_modules
[i
].library_name
);
432 return bdrv_do_find_format(format_name
);
435 static int bdrv_format_is_whitelisted(const char *format_name
, bool read_only
)
437 static const char *whitelist_rw
[] = {
438 CONFIG_BDRV_RW_WHITELIST
441 static const char *whitelist_ro
[] = {
442 CONFIG_BDRV_RO_WHITELIST
447 if (!whitelist_rw
[0] && !whitelist_ro
[0]) {
448 return 1; /* no whitelist, anything goes */
451 for (p
= whitelist_rw
; *p
; p
++) {
452 if (!strcmp(format_name
, *p
)) {
457 for (p
= whitelist_ro
; *p
; p
++) {
458 if (!strcmp(format_name
, *p
)) {
466 int bdrv_is_whitelisted(BlockDriver
*drv
, bool read_only
)
468 return bdrv_format_is_whitelisted(drv
->format_name
, read_only
);
471 bool bdrv_uses_whitelist(void)
473 return use_bdrv_whitelist
;
476 typedef struct CreateCo
{
484 static void coroutine_fn
bdrv_create_co_entry(void *opaque
)
486 Error
*local_err
= NULL
;
489 CreateCo
*cco
= opaque
;
492 ret
= cco
->drv
->bdrv_co_create_opts(cco
->drv
,
493 cco
->filename
, cco
->opts
, &local_err
);
494 error_propagate(&cco
->err
, local_err
);
498 int bdrv_create(BlockDriver
*drv
, const char* filename
,
499 QemuOpts
*opts
, Error
**errp
)
506 .filename
= g_strdup(filename
),
512 if (!drv
->bdrv_co_create_opts
) {
513 error_setg(errp
, "Driver '%s' does not support image creation", drv
->format_name
);
518 if (qemu_in_coroutine()) {
519 /* Fast-path if already in coroutine context */
520 bdrv_create_co_entry(&cco
);
522 co
= qemu_coroutine_create(bdrv_create_co_entry
, &cco
);
523 qemu_coroutine_enter(co
);
524 while (cco
.ret
== NOT_DONE
) {
525 aio_poll(qemu_get_aio_context(), true);
532 error_propagate(errp
, cco
.err
);
534 error_setg_errno(errp
, -ret
, "Could not create image");
539 g_free(cco
.filename
);
544 * Helper function for bdrv_create_file_fallback(): Resize @blk to at
545 * least the given @minimum_size.
547 * On success, return @blk's actual length.
548 * Otherwise, return -errno.
550 static int64_t create_file_fallback_truncate(BlockBackend
*blk
,
551 int64_t minimum_size
, Error
**errp
)
553 Error
*local_err
= NULL
;
557 ret
= blk_truncate(blk
, minimum_size
, false, PREALLOC_MODE_OFF
, 0,
559 if (ret
< 0 && ret
!= -ENOTSUP
) {
560 error_propagate(errp
, local_err
);
564 size
= blk_getlength(blk
);
566 error_free(local_err
);
567 error_setg_errno(errp
, -size
,
568 "Failed to inquire the new image file's length");
572 if (size
< minimum_size
) {
573 /* Need to grow the image, but we failed to do that */
574 error_propagate(errp
, local_err
);
578 error_free(local_err
);
585 * Helper function for bdrv_create_file_fallback(): Zero the first
586 * sector to remove any potentially pre-existing image header.
588 static int create_file_fallback_zero_first_sector(BlockBackend
*blk
,
589 int64_t current_size
,
592 int64_t bytes_to_clear
;
595 bytes_to_clear
= MIN(current_size
, BDRV_SECTOR_SIZE
);
596 if (bytes_to_clear
) {
597 ret
= blk_pwrite_zeroes(blk
, 0, bytes_to_clear
, BDRV_REQ_MAY_UNMAP
);
599 error_setg_errno(errp
, -ret
,
600 "Failed to clear the new image's first sector");
609 * Simple implementation of bdrv_co_create_opts for protocol drivers
610 * which only support creation via opening a file
611 * (usually existing raw storage device)
613 int coroutine_fn
bdrv_co_create_opts_simple(BlockDriver
*drv
,
614 const char *filename
,
622 PreallocMode prealloc
;
623 Error
*local_err
= NULL
;
626 size
= qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0);
627 buf
= qemu_opt_get_del(opts
, BLOCK_OPT_PREALLOC
);
628 prealloc
= qapi_enum_parse(&PreallocMode_lookup
, buf
,
629 PREALLOC_MODE_OFF
, &local_err
);
632 error_propagate(errp
, local_err
);
636 if (prealloc
!= PREALLOC_MODE_OFF
) {
637 error_setg(errp
, "Unsupported preallocation mode '%s'",
638 PreallocMode_str(prealloc
));
642 options
= qdict_new();
643 qdict_put_str(options
, "driver", drv
->format_name
);
645 blk
= blk_new_open(filename
, NULL
, options
,
646 BDRV_O_RDWR
| BDRV_O_RESIZE
, errp
);
648 error_prepend(errp
, "Protocol driver '%s' does not support image "
649 "creation, and opening the image failed: ",
654 size
= create_file_fallback_truncate(blk
, size
, errp
);
660 ret
= create_file_fallback_zero_first_sector(blk
, size
, errp
);
671 int bdrv_create_file(const char *filename
, QemuOpts
*opts
, Error
**errp
)
675 drv
= bdrv_find_protocol(filename
, true, errp
);
680 return bdrv_create(drv
, filename
, opts
, errp
);
683 int coroutine_fn
bdrv_co_delete_file(BlockDriverState
*bs
, Error
**errp
)
685 Error
*local_err
= NULL
;
691 error_setg(errp
, "Block node '%s' is not opened", bs
->filename
);
695 if (!bs
->drv
->bdrv_co_delete_file
) {
696 error_setg(errp
, "Driver '%s' does not support image deletion",
697 bs
->drv
->format_name
);
701 ret
= bs
->drv
->bdrv_co_delete_file(bs
, &local_err
);
703 error_propagate(errp
, local_err
);
710 * Try to get @bs's logical and physical block size.
711 * On success, store them in @bsz struct and return 0.
712 * On failure return -errno.
713 * @bs must not be empty.
715 int bdrv_probe_blocksizes(BlockDriverState
*bs
, BlockSizes
*bsz
)
717 BlockDriver
*drv
= bs
->drv
;
718 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
720 if (drv
&& drv
->bdrv_probe_blocksizes
) {
721 return drv
->bdrv_probe_blocksizes(bs
, bsz
);
722 } else if (filtered
) {
723 return bdrv_probe_blocksizes(filtered
, bsz
);
730 * Try to get @bs's geometry (cyls, heads, sectors).
731 * On success, store them in @geo struct and return 0.
732 * On failure return -errno.
733 * @bs must not be empty.
735 int bdrv_probe_geometry(BlockDriverState
*bs
, HDGeometry
*geo
)
737 BlockDriver
*drv
= bs
->drv
;
738 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
740 if (drv
&& drv
->bdrv_probe_geometry
) {
741 return drv
->bdrv_probe_geometry(bs
, geo
);
742 } else if (filtered
) {
743 return bdrv_probe_geometry(filtered
, geo
);
750 * Create a uniquely-named empty temporary file.
751 * Return 0 upon success, otherwise a negative errno value.
753 int get_tmp_filename(char *filename
, int size
)
756 char temp_dir
[MAX_PATH
];
757 /* GetTempFileName requires that its output buffer (4th param)
758 have length MAX_PATH or greater. */
759 assert(size
>= MAX_PATH
);
760 return (GetTempPath(MAX_PATH
, temp_dir
)
761 && GetTempFileName(temp_dir
, "qem", 0, filename
)
762 ? 0 : -GetLastError());
766 tmpdir
= getenv("TMPDIR");
770 if (snprintf(filename
, size
, "%s/vl.XXXXXX", tmpdir
) >= size
) {
773 fd
= mkstemp(filename
);
777 if (close(fd
) != 0) {
786 * Detect host devices. By convention, /dev/cdrom[N] is always
787 * recognized as a host CDROM.
789 static BlockDriver
*find_hdev_driver(const char *filename
)
791 int score_max
= 0, score
;
792 BlockDriver
*drv
= NULL
, *d
;
794 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
795 if (d
->bdrv_probe_device
) {
796 score
= d
->bdrv_probe_device(filename
);
797 if (score
> score_max
) {
807 static BlockDriver
*bdrv_do_find_protocol(const char *protocol
)
811 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
812 if (drv1
->protocol_name
&& !strcmp(drv1
->protocol_name
, protocol
)) {
820 BlockDriver
*bdrv_find_protocol(const char *filename
,
821 bool allow_protocol_prefix
,
830 /* TODO Drivers without bdrv_file_open must be specified explicitly */
833 * XXX(hch): we really should not let host device detection
834 * override an explicit protocol specification, but moving this
835 * later breaks access to device names with colons in them.
836 * Thanks to the brain-dead persistent naming schemes on udev-
837 * based Linux systems those actually are quite common.
839 drv1
= find_hdev_driver(filename
);
844 if (!path_has_protocol(filename
) || !allow_protocol_prefix
) {
848 p
= strchr(filename
, ':');
851 if (len
> sizeof(protocol
) - 1)
852 len
= sizeof(protocol
) - 1;
853 memcpy(protocol
, filename
, len
);
854 protocol
[len
] = '\0';
856 drv1
= bdrv_do_find_protocol(protocol
);
861 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
862 if (block_driver_modules
[i
].protocol_name
&&
863 !strcmp(block_driver_modules
[i
].protocol_name
, protocol
)) {
864 block_module_load_one(block_driver_modules
[i
].library_name
);
869 drv1
= bdrv_do_find_protocol(protocol
);
871 error_setg(errp
, "Unknown protocol '%s'", protocol
);
877 * Guess image format by probing its contents.
878 * This is not a good idea when your image is raw (CVE-2008-2004), but
879 * we do it anyway for backward compatibility.
881 * @buf contains the image's first @buf_size bytes.
882 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
883 * but can be smaller if the image file is smaller)
884 * @filename is its filename.
886 * For all block drivers, call the bdrv_probe() method to get its
888 * Return the first block driver with the highest probing score.
890 BlockDriver
*bdrv_probe_all(const uint8_t *buf
, int buf_size
,
891 const char *filename
)
893 int score_max
= 0, score
;
894 BlockDriver
*drv
= NULL
, *d
;
896 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
898 score
= d
->bdrv_probe(buf
, buf_size
, filename
);
899 if (score
> score_max
) {
909 static int find_image_format(BlockBackend
*file
, const char *filename
,
910 BlockDriver
**pdrv
, Error
**errp
)
913 uint8_t buf
[BLOCK_PROBE_BUF_SIZE
];
916 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
917 if (blk_is_sg(file
) || !blk_is_inserted(file
) || blk_getlength(file
) == 0) {
922 ret
= blk_pread(file
, 0, buf
, sizeof(buf
));
924 error_setg_errno(errp
, -ret
, "Could not read image for determining its "
930 drv
= bdrv_probe_all(buf
, ret
, filename
);
932 error_setg(errp
, "Could not determine image format: No compatible "
941 * Set the current 'total_sectors' value
942 * Return 0 on success, -errno on error.
944 int refresh_total_sectors(BlockDriverState
*bs
, int64_t hint
)
946 BlockDriver
*drv
= bs
->drv
;
952 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
956 /* query actual device if possible, otherwise just trust the hint */
957 if (drv
->bdrv_getlength
) {
958 int64_t length
= drv
->bdrv_getlength(bs
);
962 hint
= DIV_ROUND_UP(length
, BDRV_SECTOR_SIZE
);
965 bs
->total_sectors
= hint
;
967 if (bs
->total_sectors
* BDRV_SECTOR_SIZE
> BDRV_MAX_LENGTH
) {
975 * Combines a QDict of new block driver @options with any missing options taken
976 * from @old_options, so that leaving out an option defaults to its old value.
978 static void bdrv_join_options(BlockDriverState
*bs
, QDict
*options
,
981 if (bs
->drv
&& bs
->drv
->bdrv_join_options
) {
982 bs
->drv
->bdrv_join_options(options
, old_options
);
984 qdict_join(options
, old_options
, false);
988 static BlockdevDetectZeroesOptions
bdrv_parse_detect_zeroes(QemuOpts
*opts
,
992 Error
*local_err
= NULL
;
993 char *value
= qemu_opt_get_del(opts
, "detect-zeroes");
994 BlockdevDetectZeroesOptions detect_zeroes
=
995 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup
, value
,
996 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF
, &local_err
);
999 error_propagate(errp
, local_err
);
1000 return detect_zeroes
;
1003 if (detect_zeroes
== BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP
&&
1004 !(open_flags
& BDRV_O_UNMAP
))
1006 error_setg(errp
, "setting detect-zeroes to unmap is not allowed "
1007 "without setting discard operation to unmap");
1010 return detect_zeroes
;
1014 * Set open flags for aio engine
1016 * Return 0 on success, -1 if the engine specified is invalid
1018 int bdrv_parse_aio(const char *mode
, int *flags
)
1020 if (!strcmp(mode
, "threads")) {
1021 /* do nothing, default */
1022 } else if (!strcmp(mode
, "native")) {
1023 *flags
|= BDRV_O_NATIVE_AIO
;
1024 #ifdef CONFIG_LINUX_IO_URING
1025 } else if (!strcmp(mode
, "io_uring")) {
1026 *flags
|= BDRV_O_IO_URING
;
1036 * Set open flags for a given discard mode
1038 * Return 0 on success, -1 if the discard mode was invalid.
1040 int bdrv_parse_discard_flags(const char *mode
, int *flags
)
1042 *flags
&= ~BDRV_O_UNMAP
;
1044 if (!strcmp(mode
, "off") || !strcmp(mode
, "ignore")) {
1046 } else if (!strcmp(mode
, "on") || !strcmp(mode
, "unmap")) {
1047 *flags
|= BDRV_O_UNMAP
;
1056 * Set open flags for a given cache mode
1058 * Return 0 on success, -1 if the cache mode was invalid.
1060 int bdrv_parse_cache_mode(const char *mode
, int *flags
, bool *writethrough
)
1062 *flags
&= ~BDRV_O_CACHE_MASK
;
1064 if (!strcmp(mode
, "off") || !strcmp(mode
, "none")) {
1065 *writethrough
= false;
1066 *flags
|= BDRV_O_NOCACHE
;
1067 } else if (!strcmp(mode
, "directsync")) {
1068 *writethrough
= true;
1069 *flags
|= BDRV_O_NOCACHE
;
1070 } else if (!strcmp(mode
, "writeback")) {
1071 *writethrough
= false;
1072 } else if (!strcmp(mode
, "unsafe")) {
1073 *writethrough
= false;
1074 *flags
|= BDRV_O_NO_FLUSH
;
1075 } else if (!strcmp(mode
, "writethrough")) {
1076 *writethrough
= true;
1084 static char *bdrv_child_get_parent_desc(BdrvChild
*c
)
1086 BlockDriverState
*parent
= c
->opaque
;
1087 return g_strdup(bdrv_get_device_or_node_name(parent
));
1090 static void bdrv_child_cb_drained_begin(BdrvChild
*child
)
1092 BlockDriverState
*bs
= child
->opaque
;
1093 bdrv_do_drained_begin_quiesce(bs
, NULL
, false);
1096 static bool bdrv_child_cb_drained_poll(BdrvChild
*child
)
1098 BlockDriverState
*bs
= child
->opaque
;
1099 return bdrv_drain_poll(bs
, false, NULL
, false);
1102 static void bdrv_child_cb_drained_end(BdrvChild
*child
,
1103 int *drained_end_counter
)
1105 BlockDriverState
*bs
= child
->opaque
;
1106 bdrv_drained_end_no_poll(bs
, drained_end_counter
);
1109 static int bdrv_child_cb_inactivate(BdrvChild
*child
)
1111 BlockDriverState
*bs
= child
->opaque
;
1112 assert(bs
->open_flags
& BDRV_O_INACTIVE
);
1116 static bool bdrv_child_cb_can_set_aio_ctx(BdrvChild
*child
, AioContext
*ctx
,
1117 GSList
**ignore
, Error
**errp
)
1119 BlockDriverState
*bs
= child
->opaque
;
1120 return bdrv_can_set_aio_context(bs
, ctx
, ignore
, errp
);
1123 static void bdrv_child_cb_set_aio_ctx(BdrvChild
*child
, AioContext
*ctx
,
1126 BlockDriverState
*bs
= child
->opaque
;
1127 return bdrv_set_aio_context_ignore(bs
, ctx
, ignore
);
1131 * Returns the options and flags that a temporary snapshot should get, based on
1132 * the originally requested flags (the originally requested image will have
1133 * flags like a backing file)
1135 static void bdrv_temp_snapshot_options(int *child_flags
, QDict
*child_options
,
1136 int parent_flags
, QDict
*parent_options
)
1138 *child_flags
= (parent_flags
& ~BDRV_O_SNAPSHOT
) | BDRV_O_TEMPORARY
;
1140 /* For temporary files, unconditional cache=unsafe is fine */
1141 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_DIRECT
, "off");
1142 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_NO_FLUSH
, "on");
1144 /* Copy the read-only and discard options from the parent */
1145 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1146 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_DISCARD
);
1148 /* aio=native doesn't work for cache.direct=off, so disable it for the
1149 * temporary snapshot */
1150 *child_flags
&= ~BDRV_O_NATIVE_AIO
;
1153 static void bdrv_backing_attach(BdrvChild
*c
)
1155 BlockDriverState
*parent
= c
->opaque
;
1156 BlockDriverState
*backing_hd
= c
->bs
;
1158 assert(!parent
->backing_blocker
);
1159 error_setg(&parent
->backing_blocker
,
1160 "node is used as backing hd of '%s'",
1161 bdrv_get_device_or_node_name(parent
));
1163 bdrv_refresh_filename(backing_hd
);
1165 parent
->open_flags
&= ~BDRV_O_NO_BACKING
;
1167 bdrv_op_block_all(backing_hd
, parent
->backing_blocker
);
1168 /* Otherwise we won't be able to commit or stream */
1169 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_COMMIT_TARGET
,
1170 parent
->backing_blocker
);
1171 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_STREAM
,
1172 parent
->backing_blocker
);
1174 * We do backup in 3 ways:
1176 * The target bs is new opened, and the source is top BDS
1177 * 2. blockdev backup
1178 * Both the source and the target are top BDSes.
1179 * 3. internal backup(used for block replication)
1180 * Both the source and the target are backing file
1182 * In case 1 and 2, neither the source nor the target is the backing file.
1183 * In case 3, we will block the top BDS, so there is only one block job
1184 * for the top BDS and its backing chain.
1186 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_SOURCE
,
1187 parent
->backing_blocker
);
1188 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_TARGET
,
1189 parent
->backing_blocker
);
1192 static void bdrv_backing_detach(BdrvChild
*c
)
1194 BlockDriverState
*parent
= c
->opaque
;
1196 assert(parent
->backing_blocker
);
1197 bdrv_op_unblock_all(c
->bs
, parent
->backing_blocker
);
1198 error_free(parent
->backing_blocker
);
1199 parent
->backing_blocker
= NULL
;
1202 static int bdrv_backing_update_filename(BdrvChild
*c
, BlockDriverState
*base
,
1203 const char *filename
, Error
**errp
)
1205 BlockDriverState
*parent
= c
->opaque
;
1206 bool read_only
= bdrv_is_read_only(parent
);
1210 ret
= bdrv_reopen_set_read_only(parent
, false, errp
);
1216 ret
= bdrv_change_backing_file(parent
, filename
,
1217 base
->drv
? base
->drv
->format_name
: "",
1220 error_setg_errno(errp
, -ret
, "Could not update backing file link");
1224 bdrv_reopen_set_read_only(parent
, true, NULL
);
1231 * Returns the options and flags that a generic child of a BDS should
1232 * get, based on the given options and flags for the parent BDS.
1234 static void bdrv_inherited_options(BdrvChildRole role
, bool parent_is_format
,
1235 int *child_flags
, QDict
*child_options
,
1236 int parent_flags
, QDict
*parent_options
)
1238 int flags
= parent_flags
;
1241 * First, decide whether to set, clear, or leave BDRV_O_PROTOCOL.
1242 * Generally, the question to answer is: Should this child be
1243 * format-probed by default?
1247 * Pure and non-filtered data children of non-format nodes should
1248 * be probed by default (even when the node itself has BDRV_O_PROTOCOL
1249 * set). This only affects a very limited set of drivers (namely
1250 * quorum and blkverify when this comment was written).
1251 * Force-clear BDRV_O_PROTOCOL then.
1253 if (!parent_is_format
&&
1254 (role
& BDRV_CHILD_DATA
) &&
1255 !(role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_FILTERED
)))
1257 flags
&= ~BDRV_O_PROTOCOL
;
1261 * All children of format nodes (except for COW children) and all
1262 * metadata children in general should never be format-probed.
1263 * Force-set BDRV_O_PROTOCOL then.
1265 if ((parent_is_format
&& !(role
& BDRV_CHILD_COW
)) ||
1266 (role
& BDRV_CHILD_METADATA
))
1268 flags
|= BDRV_O_PROTOCOL
;
1272 * If the cache mode isn't explicitly set, inherit direct and no-flush from
1275 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_DIRECT
);
1276 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_NO_FLUSH
);
1277 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_FORCE_SHARE
);
1279 if (role
& BDRV_CHILD_COW
) {
1280 /* backing files are opened read-only by default */
1281 qdict_set_default_str(child_options
, BDRV_OPT_READ_ONLY
, "on");
1282 qdict_set_default_str(child_options
, BDRV_OPT_AUTO_READ_ONLY
, "off");
1284 /* Inherit the read-only option from the parent if it's not set */
1285 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1286 qdict_copy_default(child_options
, parent_options
,
1287 BDRV_OPT_AUTO_READ_ONLY
);
1291 * bdrv_co_pdiscard() respects unmap policy for the parent, so we
1292 * can default to enable it on lower layers regardless of the
1295 qdict_set_default_str(child_options
, BDRV_OPT_DISCARD
, "unmap");
1297 /* Clear flags that only apply to the top layer */
1298 flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_COPY_ON_READ
);
1300 if (role
& BDRV_CHILD_METADATA
) {
1301 flags
&= ~BDRV_O_NO_IO
;
1303 if (role
& BDRV_CHILD_COW
) {
1304 flags
&= ~BDRV_O_TEMPORARY
;
1307 *child_flags
= flags
;
1310 static void bdrv_child_cb_attach(BdrvChild
*child
)
1312 BlockDriverState
*bs
= child
->opaque
;
1314 if (child
->role
& BDRV_CHILD_COW
) {
1315 bdrv_backing_attach(child
);
1318 bdrv_apply_subtree_drain(child
, bs
);
1321 static void bdrv_child_cb_detach(BdrvChild
*child
)
1323 BlockDriverState
*bs
= child
->opaque
;
1325 if (child
->role
& BDRV_CHILD_COW
) {
1326 bdrv_backing_detach(child
);
1329 bdrv_unapply_subtree_drain(child
, bs
);
1332 static int bdrv_child_cb_update_filename(BdrvChild
*c
, BlockDriverState
*base
,
1333 const char *filename
, Error
**errp
)
1335 if (c
->role
& BDRV_CHILD_COW
) {
1336 return bdrv_backing_update_filename(c
, base
, filename
, errp
);
1341 const BdrvChildClass child_of_bds
= {
1342 .parent_is_bds
= true,
1343 .get_parent_desc
= bdrv_child_get_parent_desc
,
1344 .inherit_options
= bdrv_inherited_options
,
1345 .drained_begin
= bdrv_child_cb_drained_begin
,
1346 .drained_poll
= bdrv_child_cb_drained_poll
,
1347 .drained_end
= bdrv_child_cb_drained_end
,
1348 .attach
= bdrv_child_cb_attach
,
1349 .detach
= bdrv_child_cb_detach
,
1350 .inactivate
= bdrv_child_cb_inactivate
,
1351 .can_set_aio_ctx
= bdrv_child_cb_can_set_aio_ctx
,
1352 .set_aio_ctx
= bdrv_child_cb_set_aio_ctx
,
1353 .update_filename
= bdrv_child_cb_update_filename
,
1356 static int bdrv_open_flags(BlockDriverState
*bs
, int flags
)
1358 int open_flags
= flags
;
1361 * Clear flags that are internal to the block layer before opening the
1364 open_flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_PROTOCOL
);
1369 static void update_flags_from_options(int *flags
, QemuOpts
*opts
)
1371 *flags
&= ~(BDRV_O_CACHE_MASK
| BDRV_O_RDWR
| BDRV_O_AUTO_RDONLY
);
1373 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_NO_FLUSH
, false)) {
1374 *flags
|= BDRV_O_NO_FLUSH
;
1377 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_DIRECT
, false)) {
1378 *flags
|= BDRV_O_NOCACHE
;
1381 if (!qemu_opt_get_bool_del(opts
, BDRV_OPT_READ_ONLY
, false)) {
1382 *flags
|= BDRV_O_RDWR
;
1385 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_AUTO_READ_ONLY
, false)) {
1386 *flags
|= BDRV_O_AUTO_RDONLY
;
1390 static void update_options_from_flags(QDict
*options
, int flags
)
1392 if (!qdict_haskey(options
, BDRV_OPT_CACHE_DIRECT
)) {
1393 qdict_put_bool(options
, BDRV_OPT_CACHE_DIRECT
, flags
& BDRV_O_NOCACHE
);
1395 if (!qdict_haskey(options
, BDRV_OPT_CACHE_NO_FLUSH
)) {
1396 qdict_put_bool(options
, BDRV_OPT_CACHE_NO_FLUSH
,
1397 flags
& BDRV_O_NO_FLUSH
);
1399 if (!qdict_haskey(options
, BDRV_OPT_READ_ONLY
)) {
1400 qdict_put_bool(options
, BDRV_OPT_READ_ONLY
, !(flags
& BDRV_O_RDWR
));
1402 if (!qdict_haskey(options
, BDRV_OPT_AUTO_READ_ONLY
)) {
1403 qdict_put_bool(options
, BDRV_OPT_AUTO_READ_ONLY
,
1404 flags
& BDRV_O_AUTO_RDONLY
);
1408 static void bdrv_assign_node_name(BlockDriverState
*bs
,
1409 const char *node_name
,
1412 char *gen_node_name
= NULL
;
1415 node_name
= gen_node_name
= id_generate(ID_BLOCK
);
1416 } else if (!id_wellformed(node_name
)) {
1418 * Check for empty string or invalid characters, but not if it is
1419 * generated (generated names use characters not available to the user)
1421 error_setg(errp
, "Invalid node name");
1425 /* takes care of avoiding namespaces collisions */
1426 if (blk_by_name(node_name
)) {
1427 error_setg(errp
, "node-name=%s is conflicting with a device id",
1432 /* takes care of avoiding duplicates node names */
1433 if (bdrv_find_node(node_name
)) {
1434 error_setg(errp
, "Duplicate node name");
1438 /* Make sure that the node name isn't truncated */
1439 if (strlen(node_name
) >= sizeof(bs
->node_name
)) {
1440 error_setg(errp
, "Node name too long");
1444 /* copy node name into the bs and insert it into the graph list */
1445 pstrcpy(bs
->node_name
, sizeof(bs
->node_name
), node_name
);
1446 QTAILQ_INSERT_TAIL(&graph_bdrv_states
, bs
, node_list
);
1448 g_free(gen_node_name
);
1451 static int bdrv_open_driver(BlockDriverState
*bs
, BlockDriver
*drv
,
1452 const char *node_name
, QDict
*options
,
1453 int open_flags
, Error
**errp
)
1455 Error
*local_err
= NULL
;
1458 bdrv_assign_node_name(bs
, node_name
, &local_err
);
1460 error_propagate(errp
, local_err
);
1465 bs
->read_only
= !(bs
->open_flags
& BDRV_O_RDWR
);
1466 bs
->opaque
= g_malloc0(drv
->instance_size
);
1468 if (drv
->bdrv_file_open
) {
1469 assert(!drv
->bdrv_needs_filename
|| bs
->filename
[0]);
1470 ret
= drv
->bdrv_file_open(bs
, options
, open_flags
, &local_err
);
1471 } else if (drv
->bdrv_open
) {
1472 ret
= drv
->bdrv_open(bs
, options
, open_flags
, &local_err
);
1479 error_propagate(errp
, local_err
);
1480 } else if (bs
->filename
[0]) {
1481 error_setg_errno(errp
, -ret
, "Could not open '%s'", bs
->filename
);
1483 error_setg_errno(errp
, -ret
, "Could not open image");
1488 ret
= refresh_total_sectors(bs
, bs
->total_sectors
);
1490 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
1494 bdrv_refresh_limits(bs
, &local_err
);
1496 error_propagate(errp
, local_err
);
1500 assert(bdrv_opt_mem_align(bs
) != 0);
1501 assert(bdrv_min_mem_align(bs
) != 0);
1502 assert(is_power_of_2(bs
->bl
.request_alignment
));
1504 for (i
= 0; i
< bs
->quiesce_counter
; i
++) {
1505 if (drv
->bdrv_co_drain_begin
) {
1506 drv
->bdrv_co_drain_begin(bs
);
1513 if (bs
->file
!= NULL
) {
1514 bdrv_unref_child(bs
, bs
->file
);
1522 BlockDriverState
*bdrv_new_open_driver(BlockDriver
*drv
, const char *node_name
,
1523 int flags
, Error
**errp
)
1525 BlockDriverState
*bs
;
1529 bs
->open_flags
= flags
;
1530 bs
->explicit_options
= qdict_new();
1531 bs
->options
= qdict_new();
1534 update_options_from_flags(bs
->options
, flags
);
1536 ret
= bdrv_open_driver(bs
, drv
, node_name
, bs
->options
, flags
, errp
);
1538 qobject_unref(bs
->explicit_options
);
1539 bs
->explicit_options
= NULL
;
1540 qobject_unref(bs
->options
);
1549 QemuOptsList bdrv_runtime_opts
= {
1550 .name
= "bdrv_common",
1551 .head
= QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts
.head
),
1554 .name
= "node-name",
1555 .type
= QEMU_OPT_STRING
,
1556 .help
= "Node name of the block device node",
1560 .type
= QEMU_OPT_STRING
,
1561 .help
= "Block driver to use for the node",
1564 .name
= BDRV_OPT_CACHE_DIRECT
,
1565 .type
= QEMU_OPT_BOOL
,
1566 .help
= "Bypass software writeback cache on the host",
1569 .name
= BDRV_OPT_CACHE_NO_FLUSH
,
1570 .type
= QEMU_OPT_BOOL
,
1571 .help
= "Ignore flush requests",
1574 .name
= BDRV_OPT_READ_ONLY
,
1575 .type
= QEMU_OPT_BOOL
,
1576 .help
= "Node is opened in read-only mode",
1579 .name
= BDRV_OPT_AUTO_READ_ONLY
,
1580 .type
= QEMU_OPT_BOOL
,
1581 .help
= "Node can become read-only if opening read-write fails",
1584 .name
= "detect-zeroes",
1585 .type
= QEMU_OPT_STRING
,
1586 .help
= "try to optimize zero writes (off, on, unmap)",
1589 .name
= BDRV_OPT_DISCARD
,
1590 .type
= QEMU_OPT_STRING
,
1591 .help
= "discard operation (ignore/off, unmap/on)",
1594 .name
= BDRV_OPT_FORCE_SHARE
,
1595 .type
= QEMU_OPT_BOOL
,
1596 .help
= "always accept other writers (default: off)",
1598 { /* end of list */ }
1602 QemuOptsList bdrv_create_opts_simple
= {
1603 .name
= "simple-create-opts",
1604 .head
= QTAILQ_HEAD_INITIALIZER(bdrv_create_opts_simple
.head
),
1607 .name
= BLOCK_OPT_SIZE
,
1608 .type
= QEMU_OPT_SIZE
,
1609 .help
= "Virtual disk size"
1612 .name
= BLOCK_OPT_PREALLOC
,
1613 .type
= QEMU_OPT_STRING
,
1614 .help
= "Preallocation mode (allowed values: off)"
1616 { /* end of list */ }
1621 * Common part for opening disk images and files
1623 * Removes all processed options from *options.
1625 static int bdrv_open_common(BlockDriverState
*bs
, BlockBackend
*file
,
1626 QDict
*options
, Error
**errp
)
1628 int ret
, open_flags
;
1629 const char *filename
;
1630 const char *driver_name
= NULL
;
1631 const char *node_name
= NULL
;
1632 const char *discard
;
1635 Error
*local_err
= NULL
;
1637 assert(bs
->file
== NULL
);
1638 assert(options
!= NULL
&& bs
->options
!= options
);
1640 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
1641 if (!qemu_opts_absorb_qdict(opts
, options
, errp
)) {
1646 update_flags_from_options(&bs
->open_flags
, opts
);
1648 driver_name
= qemu_opt_get(opts
, "driver");
1649 drv
= bdrv_find_format(driver_name
);
1650 assert(drv
!= NULL
);
1652 bs
->force_share
= qemu_opt_get_bool(opts
, BDRV_OPT_FORCE_SHARE
, false);
1654 if (bs
->force_share
&& (bs
->open_flags
& BDRV_O_RDWR
)) {
1656 BDRV_OPT_FORCE_SHARE
1657 "=on can only be used with read-only images");
1663 bdrv_refresh_filename(blk_bs(file
));
1664 filename
= blk_bs(file
)->filename
;
1667 * Caution: while qdict_get_try_str() is fine, getting
1668 * non-string types would require more care. When @options
1669 * come from -blockdev or blockdev_add, its members are typed
1670 * according to the QAPI schema, but when they come from
1671 * -drive, they're all QString.
1673 filename
= qdict_get_try_str(options
, "filename");
1676 if (drv
->bdrv_needs_filename
&& (!filename
|| !filename
[0])) {
1677 error_setg(errp
, "The '%s' block driver requires a file name",
1683 trace_bdrv_open_common(bs
, filename
?: "", bs
->open_flags
,
1686 bs
->read_only
= !(bs
->open_flags
& BDRV_O_RDWR
);
1688 if (use_bdrv_whitelist
&& !bdrv_is_whitelisted(drv
, bs
->read_only
)) {
1689 if (!bs
->read_only
&& bdrv_is_whitelisted(drv
, true)) {
1690 ret
= bdrv_apply_auto_read_only(bs
, NULL
, NULL
);
1696 !bs
->read_only
&& bdrv_is_whitelisted(drv
, true)
1697 ? "Driver '%s' can only be used for read-only devices"
1698 : "Driver '%s' is not whitelisted",
1704 /* bdrv_new() and bdrv_close() make it so */
1705 assert(qatomic_read(&bs
->copy_on_read
) == 0);
1707 if (bs
->open_flags
& BDRV_O_COPY_ON_READ
) {
1708 if (!bs
->read_only
) {
1709 bdrv_enable_copy_on_read(bs
);
1711 error_setg(errp
, "Can't use copy-on-read on read-only device");
1717 discard
= qemu_opt_get(opts
, BDRV_OPT_DISCARD
);
1718 if (discard
!= NULL
) {
1719 if (bdrv_parse_discard_flags(discard
, &bs
->open_flags
) != 0) {
1720 error_setg(errp
, "Invalid discard option");
1727 bdrv_parse_detect_zeroes(opts
, bs
->open_flags
, &local_err
);
1729 error_propagate(errp
, local_err
);
1734 if (filename
!= NULL
) {
1735 pstrcpy(bs
->filename
, sizeof(bs
->filename
), filename
);
1737 bs
->filename
[0] = '\0';
1739 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
), bs
->filename
);
1741 /* Open the image, either directly or using a protocol */
1742 open_flags
= bdrv_open_flags(bs
, bs
->open_flags
);
1743 node_name
= qemu_opt_get(opts
, "node-name");
1745 assert(!drv
->bdrv_file_open
|| file
== NULL
);
1746 ret
= bdrv_open_driver(bs
, drv
, node_name
, options
, open_flags
, errp
);
1751 qemu_opts_del(opts
);
1755 qemu_opts_del(opts
);
1759 static QDict
*parse_json_filename(const char *filename
, Error
**errp
)
1761 QObject
*options_obj
;
1765 ret
= strstart(filename
, "json:", &filename
);
1768 options_obj
= qobject_from_json(filename
, errp
);
1770 error_prepend(errp
, "Could not parse the JSON options: ");
1774 options
= qobject_to(QDict
, options_obj
);
1776 qobject_unref(options_obj
);
1777 error_setg(errp
, "Invalid JSON object given");
1781 qdict_flatten(options
);
1786 static void parse_json_protocol(QDict
*options
, const char **pfilename
,
1789 QDict
*json_options
;
1790 Error
*local_err
= NULL
;
1792 /* Parse json: pseudo-protocol */
1793 if (!*pfilename
|| !g_str_has_prefix(*pfilename
, "json:")) {
1797 json_options
= parse_json_filename(*pfilename
, &local_err
);
1799 error_propagate(errp
, local_err
);
1803 /* Options given in the filename have lower priority than options
1804 * specified directly */
1805 qdict_join(options
, json_options
, false);
1806 qobject_unref(json_options
);
1811 * Fills in default options for opening images and converts the legacy
1812 * filename/flags pair to option QDict entries.
1813 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1814 * block driver has been specified explicitly.
1816 static int bdrv_fill_options(QDict
**options
, const char *filename
,
1817 int *flags
, Error
**errp
)
1819 const char *drvname
;
1820 bool protocol
= *flags
& BDRV_O_PROTOCOL
;
1821 bool parse_filename
= false;
1822 BlockDriver
*drv
= NULL
;
1823 Error
*local_err
= NULL
;
1826 * Caution: while qdict_get_try_str() is fine, getting non-string
1827 * types would require more care. When @options come from
1828 * -blockdev or blockdev_add, its members are typed according to
1829 * the QAPI schema, but when they come from -drive, they're all
1832 drvname
= qdict_get_try_str(*options
, "driver");
1834 drv
= bdrv_find_format(drvname
);
1836 error_setg(errp
, "Unknown driver '%s'", drvname
);
1839 /* If the user has explicitly specified the driver, this choice should
1840 * override the BDRV_O_PROTOCOL flag */
1841 protocol
= drv
->bdrv_file_open
;
1845 *flags
|= BDRV_O_PROTOCOL
;
1847 *flags
&= ~BDRV_O_PROTOCOL
;
1850 /* Translate cache options from flags into options */
1851 update_options_from_flags(*options
, *flags
);
1853 /* Fetch the file name from the options QDict if necessary */
1854 if (protocol
&& filename
) {
1855 if (!qdict_haskey(*options
, "filename")) {
1856 qdict_put_str(*options
, "filename", filename
);
1857 parse_filename
= true;
1859 error_setg(errp
, "Can't specify 'file' and 'filename' options at "
1865 /* Find the right block driver */
1866 /* See cautionary note on accessing @options above */
1867 filename
= qdict_get_try_str(*options
, "filename");
1869 if (!drvname
&& protocol
) {
1871 drv
= bdrv_find_protocol(filename
, parse_filename
, errp
);
1876 drvname
= drv
->format_name
;
1877 qdict_put_str(*options
, "driver", drvname
);
1879 error_setg(errp
, "Must specify either driver or file");
1884 assert(drv
|| !protocol
);
1886 /* Driver-specific filename parsing */
1887 if (drv
&& drv
->bdrv_parse_filename
&& parse_filename
) {
1888 drv
->bdrv_parse_filename(filename
, *options
, &local_err
);
1890 error_propagate(errp
, local_err
);
1894 if (!drv
->bdrv_needs_filename
) {
1895 qdict_del(*options
, "filename");
1902 static int bdrv_child_check_perm(BdrvChild
*c
, BlockReopenQueue
*q
,
1903 uint64_t perm
, uint64_t shared
,
1904 GSList
*ignore_children
, Error
**errp
);
1905 static void bdrv_child_abort_perm_update(BdrvChild
*c
);
1906 static void bdrv_child_set_perm(BdrvChild
*c
);
1908 typedef struct BlockReopenQueueEntry
{
1911 BDRVReopenState state
;
1912 QTAILQ_ENTRY(BlockReopenQueueEntry
) entry
;
1913 } BlockReopenQueueEntry
;
1916 * Return the flags that @bs will have after the reopens in @q have
1917 * successfully completed. If @q is NULL (or @bs is not contained in @q),
1918 * return the current flags.
1920 static int bdrv_reopen_get_flags(BlockReopenQueue
*q
, BlockDriverState
*bs
)
1922 BlockReopenQueueEntry
*entry
;
1925 QTAILQ_FOREACH(entry
, q
, entry
) {
1926 if (entry
->state
.bs
== bs
) {
1927 return entry
->state
.flags
;
1932 return bs
->open_flags
;
1935 /* Returns whether the image file can be written to after the reopen queue @q
1936 * has been successfully applied, or right now if @q is NULL. */
1937 static bool bdrv_is_writable_after_reopen(BlockDriverState
*bs
,
1938 BlockReopenQueue
*q
)
1940 int flags
= bdrv_reopen_get_flags(q
, bs
);
1942 return (flags
& (BDRV_O_RDWR
| BDRV_O_INACTIVE
)) == BDRV_O_RDWR
;
1946 * Return whether the BDS can be written to. This is not necessarily
1947 * the same as !bdrv_is_read_only(bs), as inactivated images may not
1948 * be written to but do not count as read-only images.
1950 bool bdrv_is_writable(BlockDriverState
*bs
)
1952 return bdrv_is_writable_after_reopen(bs
, NULL
);
1955 static void bdrv_child_perm(BlockDriverState
*bs
, BlockDriverState
*child_bs
,
1956 BdrvChild
*c
, BdrvChildRole role
,
1957 BlockReopenQueue
*reopen_queue
,
1958 uint64_t parent_perm
, uint64_t parent_shared
,
1959 uint64_t *nperm
, uint64_t *nshared
)
1961 assert(bs
->drv
&& bs
->drv
->bdrv_child_perm
);
1962 bs
->drv
->bdrv_child_perm(bs
, c
, role
, reopen_queue
,
1963 parent_perm
, parent_shared
,
1965 /* TODO Take force_share from reopen_queue */
1966 if (child_bs
&& child_bs
->force_share
) {
1967 *nshared
= BLK_PERM_ALL
;
1972 * Check whether permissions on this node can be changed in a way that
1973 * @cumulative_perms and @cumulative_shared_perms are the new cumulative
1974 * permissions of all its parents. This involves checking whether all necessary
1975 * permission changes to child nodes can be performed.
1977 * A call to this function must always be followed by a call to bdrv_set_perm()
1978 * or bdrv_abort_perm_update().
1980 static int bdrv_check_perm(BlockDriverState
*bs
, BlockReopenQueue
*q
,
1981 uint64_t cumulative_perms
,
1982 uint64_t cumulative_shared_perms
,
1983 GSList
*ignore_children
, Error
**errp
)
1985 BlockDriver
*drv
= bs
->drv
;
1989 /* Write permissions never work with read-only images */
1990 if ((cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) &&
1991 !bdrv_is_writable_after_reopen(bs
, q
))
1993 if (!bdrv_is_writable_after_reopen(bs
, NULL
)) {
1994 error_setg(errp
, "Block node is read-only");
1996 uint64_t current_perms
, current_shared
;
1997 bdrv_get_cumulative_perm(bs
, ¤t_perms
, ¤t_shared
);
1998 if (current_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) {
1999 error_setg(errp
, "Cannot make block node read-only, there is "
2002 error_setg(errp
, "Cannot make block node read-only and create "
2011 * Unaligned requests will automatically be aligned to bl.request_alignment
2012 * and without RESIZE we can't extend requests to write to space beyond the
2013 * end of the image, so it's required that the image size is aligned.
2015 if ((cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) &&
2016 !(cumulative_perms
& BLK_PERM_RESIZE
))
2018 if ((bs
->total_sectors
* BDRV_SECTOR_SIZE
) % bs
->bl
.request_alignment
) {
2019 error_setg(errp
, "Cannot get 'write' permission without 'resize': "
2020 "Image size is not a multiple of request "
2026 /* Check this node */
2031 if (drv
->bdrv_check_perm
) {
2032 ret
= drv
->bdrv_check_perm(bs
, cumulative_perms
,
2033 cumulative_shared_perms
, errp
);
2039 /* Drivers that never have children can omit .bdrv_child_perm() */
2040 if (!drv
->bdrv_child_perm
) {
2041 assert(QLIST_EMPTY(&bs
->children
));
2045 /* Check all children */
2046 QLIST_FOREACH(c
, &bs
->children
, next
) {
2047 uint64_t cur_perm
, cur_shared
;
2049 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, q
,
2050 cumulative_perms
, cumulative_shared_perms
,
2051 &cur_perm
, &cur_shared
);
2052 ret
= bdrv_child_check_perm(c
, q
, cur_perm
, cur_shared
, ignore_children
,
2063 * Notifies drivers that after a previous bdrv_check_perm() call, the
2064 * permission update is not performed and any preparations made for it (e.g.
2065 * taken file locks) need to be undone.
2067 * This function recursively notifies all child nodes.
2069 static void bdrv_abort_perm_update(BlockDriverState
*bs
)
2071 BlockDriver
*drv
= bs
->drv
;
2078 if (drv
->bdrv_abort_perm_update
) {
2079 drv
->bdrv_abort_perm_update(bs
);
2082 QLIST_FOREACH(c
, &bs
->children
, next
) {
2083 bdrv_child_abort_perm_update(c
);
2087 static void bdrv_set_perm(BlockDriverState
*bs
)
2089 uint64_t cumulative_perms
, cumulative_shared_perms
;
2090 BlockDriver
*drv
= bs
->drv
;
2097 bdrv_get_cumulative_perm(bs
, &cumulative_perms
, &cumulative_shared_perms
);
2099 /* Update this node */
2100 if (drv
->bdrv_set_perm
) {
2101 drv
->bdrv_set_perm(bs
, cumulative_perms
, cumulative_shared_perms
);
2104 /* Drivers that never have children can omit .bdrv_child_perm() */
2105 if (!drv
->bdrv_child_perm
) {
2106 assert(QLIST_EMPTY(&bs
->children
));
2110 /* Update all children */
2111 QLIST_FOREACH(c
, &bs
->children
, next
) {
2112 bdrv_child_set_perm(c
);
2116 void bdrv_get_cumulative_perm(BlockDriverState
*bs
, uint64_t *perm
,
2117 uint64_t *shared_perm
)
2120 uint64_t cumulative_perms
= 0;
2121 uint64_t cumulative_shared_perms
= BLK_PERM_ALL
;
2123 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
2124 cumulative_perms
|= c
->perm
;
2125 cumulative_shared_perms
&= c
->shared_perm
;
2128 *perm
= cumulative_perms
;
2129 *shared_perm
= cumulative_shared_perms
;
2132 static char *bdrv_child_user_desc(BdrvChild
*c
)
2134 if (c
->klass
->get_parent_desc
) {
2135 return c
->klass
->get_parent_desc(c
);
2138 return g_strdup("another user");
2141 char *bdrv_perm_names(uint64_t perm
)
2147 { BLK_PERM_CONSISTENT_READ
, "consistent read" },
2148 { BLK_PERM_WRITE
, "write" },
2149 { BLK_PERM_WRITE_UNCHANGED
, "write unchanged" },
2150 { BLK_PERM_RESIZE
, "resize" },
2151 { BLK_PERM_GRAPH_MOD
, "change children" },
2155 GString
*result
= g_string_sized_new(30);
2156 struct perm_name
*p
;
2158 for (p
= permissions
; p
->name
; p
++) {
2159 if (perm
& p
->perm
) {
2160 if (result
->len
> 0) {
2161 g_string_append(result
, ", ");
2163 g_string_append(result
, p
->name
);
2167 return g_string_free(result
, FALSE
);
2171 * Checks whether a new reference to @bs can be added if the new user requires
2172 * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is
2173 * set, the BdrvChild objects in this list are ignored in the calculations;
2174 * this allows checking permission updates for an existing reference.
2176 * Needs to be followed by a call to either bdrv_set_perm() or
2177 * bdrv_abort_perm_update(). */
2178 static int bdrv_check_update_perm(BlockDriverState
*bs
, BlockReopenQueue
*q
,
2179 uint64_t new_used_perm
,
2180 uint64_t new_shared_perm
,
2181 GSList
*ignore_children
,
2185 uint64_t cumulative_perms
= new_used_perm
;
2186 uint64_t cumulative_shared_perms
= new_shared_perm
;
2189 /* There is no reason why anyone couldn't tolerate write_unchanged */
2190 assert(new_shared_perm
& BLK_PERM_WRITE_UNCHANGED
);
2192 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
2193 if (g_slist_find(ignore_children
, c
)) {
2197 if ((new_used_perm
& c
->shared_perm
) != new_used_perm
) {
2198 char *user
= bdrv_child_user_desc(c
);
2199 char *perm_names
= bdrv_perm_names(new_used_perm
& ~c
->shared_perm
);
2201 error_setg(errp
, "Conflicts with use by %s as '%s', which does not "
2203 user
, c
->name
, perm_names
, bdrv_get_node_name(c
->bs
));
2209 if ((c
->perm
& new_shared_perm
) != c
->perm
) {
2210 char *user
= bdrv_child_user_desc(c
);
2211 char *perm_names
= bdrv_perm_names(c
->perm
& ~new_shared_perm
);
2213 error_setg(errp
, "Conflicts with use by %s as '%s', which uses "
2215 user
, c
->name
, perm_names
, bdrv_get_node_name(c
->bs
));
2221 cumulative_perms
|= c
->perm
;
2222 cumulative_shared_perms
&= c
->shared_perm
;
2225 return bdrv_check_perm(bs
, q
, cumulative_perms
, cumulative_shared_perms
,
2226 ignore_children
, errp
);
2229 /* Needs to be followed by a call to either bdrv_child_set_perm() or
2230 * bdrv_child_abort_perm_update(). */
2231 static int bdrv_child_check_perm(BdrvChild
*c
, BlockReopenQueue
*q
,
2232 uint64_t perm
, uint64_t shared
,
2233 GSList
*ignore_children
, Error
**errp
)
2237 ignore_children
= g_slist_prepend(g_slist_copy(ignore_children
), c
);
2238 ret
= bdrv_check_update_perm(c
->bs
, q
, perm
, shared
, ignore_children
, errp
);
2239 g_slist_free(ignore_children
);
2245 if (!c
->has_backup_perm
) {
2246 c
->has_backup_perm
= true;
2247 c
->backup_perm
= c
->perm
;
2248 c
->backup_shared_perm
= c
->shared_perm
;
2251 * Note: it's OK if c->has_backup_perm was already set, as we can find the
2252 * same child twice during check_perm procedure
2256 c
->shared_perm
= shared
;
2261 static void bdrv_child_set_perm(BdrvChild
*c
)
2263 c
->has_backup_perm
= false;
2265 bdrv_set_perm(c
->bs
);
2268 static void bdrv_child_abort_perm_update(BdrvChild
*c
)
2270 if (c
->has_backup_perm
) {
2271 c
->perm
= c
->backup_perm
;
2272 c
->shared_perm
= c
->backup_shared_perm
;
2273 c
->has_backup_perm
= false;
2276 bdrv_abort_perm_update(c
->bs
);
2279 static int bdrv_refresh_perms(BlockDriverState
*bs
, Error
**errp
)
2282 uint64_t perm
, shared_perm
;
2284 bdrv_get_cumulative_perm(bs
, &perm
, &shared_perm
);
2285 ret
= bdrv_check_perm(bs
, NULL
, perm
, shared_perm
, NULL
, errp
);
2287 bdrv_abort_perm_update(bs
);
2295 int bdrv_child_try_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
,
2298 Error
*local_err
= NULL
;
2301 ret
= bdrv_child_check_perm(c
, NULL
, perm
, shared
, NULL
, &local_err
);
2303 bdrv_child_abort_perm_update(c
);
2304 if ((perm
& ~c
->perm
) || (c
->shared_perm
& ~shared
)) {
2305 /* tighten permissions */
2306 error_propagate(errp
, local_err
);
2309 * Our caller may intend to only loosen restrictions and
2310 * does not expect this function to fail. Errors are not
2311 * fatal in such a case, so we can just hide them from our
2314 error_free(local_err
);
2320 bdrv_child_set_perm(c
);
2325 int bdrv_child_refresh_perms(BlockDriverState
*bs
, BdrvChild
*c
, Error
**errp
)
2327 uint64_t parent_perms
, parent_shared
;
2328 uint64_t perms
, shared
;
2330 bdrv_get_cumulative_perm(bs
, &parent_perms
, &parent_shared
);
2331 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, NULL
,
2332 parent_perms
, parent_shared
, &perms
, &shared
);
2334 return bdrv_child_try_set_perm(c
, perms
, shared
, errp
);
2338 * Default implementation for .bdrv_child_perm() for block filters:
2339 * Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED, and RESIZE to the
2342 static void bdrv_filter_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2344 BlockReopenQueue
*reopen_queue
,
2345 uint64_t perm
, uint64_t shared
,
2346 uint64_t *nperm
, uint64_t *nshared
)
2348 *nperm
= perm
& DEFAULT_PERM_PASSTHROUGH
;
2349 *nshared
= (shared
& DEFAULT_PERM_PASSTHROUGH
) | DEFAULT_PERM_UNCHANGED
;
2352 static void bdrv_default_perms_for_cow(BlockDriverState
*bs
, BdrvChild
*c
,
2354 BlockReopenQueue
*reopen_queue
,
2355 uint64_t perm
, uint64_t shared
,
2356 uint64_t *nperm
, uint64_t *nshared
)
2358 assert(role
& BDRV_CHILD_COW
);
2361 * We want consistent read from backing files if the parent needs it.
2362 * No other operations are performed on backing files.
2364 perm
&= BLK_PERM_CONSISTENT_READ
;
2367 * If the parent can deal with changing data, we're okay with a
2368 * writable and resizable backing file.
2369 * TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too?
2371 if (shared
& BLK_PERM_WRITE
) {
2372 shared
= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2377 shared
|= BLK_PERM_CONSISTENT_READ
| BLK_PERM_GRAPH_MOD
|
2378 BLK_PERM_WRITE_UNCHANGED
;
2380 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
2381 shared
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2388 static void bdrv_default_perms_for_storage(BlockDriverState
*bs
, BdrvChild
*c
,
2390 BlockReopenQueue
*reopen_queue
,
2391 uint64_t perm
, uint64_t shared
,
2392 uint64_t *nperm
, uint64_t *nshared
)
2396 assert(role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_DATA
));
2398 flags
= bdrv_reopen_get_flags(reopen_queue
, bs
);
2401 * Apart from the modifications below, the same permissions are
2402 * forwarded and left alone as for filters
2404 bdrv_filter_default_perms(bs
, c
, role
, reopen_queue
,
2405 perm
, shared
, &perm
, &shared
);
2407 if (role
& BDRV_CHILD_METADATA
) {
2408 /* Format drivers may touch metadata even if the guest doesn't write */
2409 if (bdrv_is_writable_after_reopen(bs
, reopen_queue
)) {
2410 perm
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2414 * bs->file always needs to be consistent because of the
2415 * metadata. We can never allow other users to resize or write
2418 if (!(flags
& BDRV_O_NO_IO
)) {
2419 perm
|= BLK_PERM_CONSISTENT_READ
;
2421 shared
&= ~(BLK_PERM_WRITE
| BLK_PERM_RESIZE
);
2424 if (role
& BDRV_CHILD_DATA
) {
2426 * Technically, everything in this block is a subset of the
2427 * BDRV_CHILD_METADATA path taken above, and so this could
2428 * be an "else if" branch. However, that is not obvious, and
2429 * this function is not performance critical, therefore we let
2430 * this be an independent "if".
2434 * We cannot allow other users to resize the file because the
2435 * format driver might have some assumptions about the size
2436 * (e.g. because it is stored in metadata, or because the file
2437 * is split into fixed-size data files).
2439 shared
&= ~BLK_PERM_RESIZE
;
2442 * WRITE_UNCHANGED often cannot be performed as such on the
2443 * data file. For example, the qcow2 driver may still need to
2444 * write copied clusters on copy-on-read.
2446 if (perm
& BLK_PERM_WRITE_UNCHANGED
) {
2447 perm
|= BLK_PERM_WRITE
;
2451 * If the data file is written to, the format driver may
2452 * expect to be able to resize it by writing beyond the EOF.
2454 if (perm
& BLK_PERM_WRITE
) {
2455 perm
|= BLK_PERM_RESIZE
;
2459 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
2460 shared
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2467 void bdrv_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2468 BdrvChildRole role
, BlockReopenQueue
*reopen_queue
,
2469 uint64_t perm
, uint64_t shared
,
2470 uint64_t *nperm
, uint64_t *nshared
)
2472 if (role
& BDRV_CHILD_FILTERED
) {
2473 assert(!(role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
|
2475 bdrv_filter_default_perms(bs
, c
, role
, reopen_queue
,
2476 perm
, shared
, nperm
, nshared
);
2477 } else if (role
& BDRV_CHILD_COW
) {
2478 assert(!(role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
)));
2479 bdrv_default_perms_for_cow(bs
, c
, role
, reopen_queue
,
2480 perm
, shared
, nperm
, nshared
);
2481 } else if (role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_DATA
)) {
2482 bdrv_default_perms_for_storage(bs
, c
, role
, reopen_queue
,
2483 perm
, shared
, nperm
, nshared
);
2485 g_assert_not_reached();
2489 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm
)
2491 static const uint64_t permissions
[] = {
2492 [BLOCK_PERMISSION_CONSISTENT_READ
] = BLK_PERM_CONSISTENT_READ
,
2493 [BLOCK_PERMISSION_WRITE
] = BLK_PERM_WRITE
,
2494 [BLOCK_PERMISSION_WRITE_UNCHANGED
] = BLK_PERM_WRITE_UNCHANGED
,
2495 [BLOCK_PERMISSION_RESIZE
] = BLK_PERM_RESIZE
,
2496 [BLOCK_PERMISSION_GRAPH_MOD
] = BLK_PERM_GRAPH_MOD
,
2499 QEMU_BUILD_BUG_ON(ARRAY_SIZE(permissions
) != BLOCK_PERMISSION__MAX
);
2500 QEMU_BUILD_BUG_ON(1UL << ARRAY_SIZE(permissions
) != BLK_PERM_ALL
+ 1);
2502 assert(qapi_perm
< BLOCK_PERMISSION__MAX
);
2504 return permissions
[qapi_perm
];
2507 static void bdrv_replace_child_noperm(BdrvChild
*child
,
2508 BlockDriverState
*new_bs
)
2510 BlockDriverState
*old_bs
= child
->bs
;
2511 int new_bs_quiesce_counter
;
2514 assert(!child
->frozen
);
2516 if (old_bs
&& new_bs
) {
2517 assert(bdrv_get_aio_context(old_bs
) == bdrv_get_aio_context(new_bs
));
2520 new_bs_quiesce_counter
= (new_bs
? new_bs
->quiesce_counter
: 0);
2521 drain_saldo
= new_bs_quiesce_counter
- child
->parent_quiesce_counter
;
2524 * If the new child node is drained but the old one was not, flush
2525 * all outstanding requests to the old child node.
2527 while (drain_saldo
> 0 && child
->klass
->drained_begin
) {
2528 bdrv_parent_drained_begin_single(child
, true);
2533 /* Detach first so that the recursive drain sections coming from @child
2534 * are already gone and we only end the drain sections that came from
2536 if (child
->klass
->detach
) {
2537 child
->klass
->detach(child
);
2539 QLIST_REMOVE(child
, next_parent
);
2545 QLIST_INSERT_HEAD(&new_bs
->parents
, child
, next_parent
);
2548 * Detaching the old node may have led to the new node's
2549 * quiesce_counter having been decreased. Not a problem, we
2550 * just need to recognize this here and then invoke
2551 * drained_end appropriately more often.
2553 assert(new_bs
->quiesce_counter
<= new_bs_quiesce_counter
);
2554 drain_saldo
+= new_bs
->quiesce_counter
- new_bs_quiesce_counter
;
2556 /* Attach only after starting new drained sections, so that recursive
2557 * drain sections coming from @child don't get an extra .drained_begin
2559 if (child
->klass
->attach
) {
2560 child
->klass
->attach(child
);
2565 * If the old child node was drained but the new one is not, allow
2566 * requests to come in only after the new node has been attached.
2568 while (drain_saldo
< 0 && child
->klass
->drained_end
) {
2569 bdrv_parent_drained_end_single(child
);
2575 * Updates @child to change its reference to point to @new_bs, including
2576 * checking and applying the necessary permission updates both to the old node
2579 * NULL is passed as @new_bs for removing the reference before freeing @child.
2581 * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this
2582 * function uses bdrv_set_perm() to update the permissions according to the new
2583 * reference that @new_bs gets.
2585 * Callers must ensure that child->frozen is false.
2587 static void bdrv_replace_child(BdrvChild
*child
, BlockDriverState
*new_bs
)
2589 BlockDriverState
*old_bs
= child
->bs
;
2591 /* Asserts that child->frozen == false */
2592 bdrv_replace_child_noperm(child
, new_bs
);
2595 * Start with the new node's permissions. If @new_bs is a (direct
2596 * or indirect) child of @old_bs, we must complete the permission
2597 * update on @new_bs before we loosen the restrictions on @old_bs.
2598 * Otherwise, bdrv_check_perm() on @old_bs would re-initiate
2599 * updating the permissions of @new_bs, and thus not purely loosen
2603 bdrv_set_perm(new_bs
);
2608 * Update permissions for old node. We're just taking a parent away, so
2609 * we're loosening restrictions. Errors of permission update are not
2610 * fatal in this case, ignore them.
2612 bdrv_refresh_perms(old_bs
, NULL
);
2614 /* When the parent requiring a non-default AioContext is removed, the
2615 * node moves back to the main AioContext */
2616 bdrv_try_set_aio_context(old_bs
, qemu_get_aio_context(), NULL
);
2621 * This function steals the reference to child_bs from the caller.
2622 * That reference is later dropped by bdrv_root_unref_child().
2624 * On failure NULL is returned, errp is set and the reference to
2625 * child_bs is also dropped.
2627 * The caller must hold the AioContext lock @child_bs, but not that of @ctx
2628 * (unless @child_bs is already in @ctx).
2630 BdrvChild
*bdrv_root_attach_child(BlockDriverState
*child_bs
,
2631 const char *child_name
,
2632 const BdrvChildClass
*child_class
,
2633 BdrvChildRole child_role
,
2635 uint64_t perm
, uint64_t shared_perm
,
2636 void *opaque
, Error
**errp
)
2639 Error
*local_err
= NULL
;
2642 ret
= bdrv_check_update_perm(child_bs
, NULL
, perm
, shared_perm
, NULL
, errp
);
2644 bdrv_abort_perm_update(child_bs
);
2645 bdrv_unref(child_bs
);
2649 child
= g_new(BdrvChild
, 1);
2650 *child
= (BdrvChild
) {
2652 .name
= g_strdup(child_name
),
2653 .klass
= child_class
,
2656 .shared_perm
= shared_perm
,
2660 /* If the AioContexts don't match, first try to move the subtree of
2661 * child_bs into the AioContext of the new parent. If this doesn't work,
2662 * try moving the parent into the AioContext of child_bs instead. */
2663 if (bdrv_get_aio_context(child_bs
) != ctx
) {
2664 ret
= bdrv_try_set_aio_context(child_bs
, ctx
, &local_err
);
2665 if (ret
< 0 && child_class
->can_set_aio_ctx
) {
2666 GSList
*ignore
= g_slist_prepend(NULL
, child
);
2667 ctx
= bdrv_get_aio_context(child_bs
);
2668 if (child_class
->can_set_aio_ctx(child
, ctx
, &ignore
, NULL
)) {
2669 error_free(local_err
);
2671 g_slist_free(ignore
);
2672 ignore
= g_slist_prepend(NULL
, child
);
2673 child_class
->set_aio_ctx(child
, ctx
, &ignore
);
2675 g_slist_free(ignore
);
2678 error_propagate(errp
, local_err
);
2680 bdrv_abort_perm_update(child_bs
);
2681 bdrv_unref(child_bs
);
2686 /* This performs the matching bdrv_set_perm() for the above check. */
2687 bdrv_replace_child(child
, child_bs
);
2693 * This function transfers the reference to child_bs from the caller
2694 * to parent_bs. That reference is later dropped by parent_bs on
2695 * bdrv_close() or if someone calls bdrv_unref_child().
2697 * On failure NULL is returned, errp is set and the reference to
2698 * child_bs is also dropped.
2700 * If @parent_bs and @child_bs are in different AioContexts, the caller must
2701 * hold the AioContext lock for @child_bs, but not for @parent_bs.
2703 BdrvChild
*bdrv_attach_child(BlockDriverState
*parent_bs
,
2704 BlockDriverState
*child_bs
,
2705 const char *child_name
,
2706 const BdrvChildClass
*child_class
,
2707 BdrvChildRole child_role
,
2711 uint64_t perm
, shared_perm
;
2713 bdrv_get_cumulative_perm(parent_bs
, &perm
, &shared_perm
);
2715 assert(parent_bs
->drv
);
2716 bdrv_child_perm(parent_bs
, child_bs
, NULL
, child_role
, NULL
,
2717 perm
, shared_perm
, &perm
, &shared_perm
);
2719 child
= bdrv_root_attach_child(child_bs
, child_name
, child_class
,
2720 child_role
, bdrv_get_aio_context(parent_bs
),
2721 perm
, shared_perm
, parent_bs
, errp
);
2722 if (child
== NULL
) {
2726 QLIST_INSERT_HEAD(&parent_bs
->children
, child
, next
);
2730 static void bdrv_detach_child(BdrvChild
*child
)
2732 QLIST_SAFE_REMOVE(child
, next
);
2734 bdrv_replace_child(child
, NULL
);
2736 g_free(child
->name
);
2740 /* Callers must ensure that child->frozen is false. */
2741 void bdrv_root_unref_child(BdrvChild
*child
)
2743 BlockDriverState
*child_bs
;
2745 child_bs
= child
->bs
;
2746 bdrv_detach_child(child
);
2747 bdrv_unref(child_bs
);
2751 * Clear all inherits_from pointers from children and grandchildren of
2752 * @root that point to @root, where necessary.
2754 static void bdrv_unset_inherits_from(BlockDriverState
*root
, BdrvChild
*child
)
2758 if (child
->bs
->inherits_from
== root
) {
2760 * Remove inherits_from only when the last reference between root and
2761 * child->bs goes away.
2763 QLIST_FOREACH(c
, &root
->children
, next
) {
2764 if (c
!= child
&& c
->bs
== child
->bs
) {
2769 child
->bs
->inherits_from
= NULL
;
2773 QLIST_FOREACH(c
, &child
->bs
->children
, next
) {
2774 bdrv_unset_inherits_from(root
, c
);
2778 /* Callers must ensure that child->frozen is false. */
2779 void bdrv_unref_child(BlockDriverState
*parent
, BdrvChild
*child
)
2781 if (child
== NULL
) {
2785 bdrv_unset_inherits_from(parent
, child
);
2786 bdrv_root_unref_child(child
);
2790 static void bdrv_parent_cb_change_media(BlockDriverState
*bs
, bool load
)
2793 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
2794 if (c
->klass
->change_media
) {
2795 c
->klass
->change_media(c
, load
);
2800 /* Return true if you can reach parent going through child->inherits_from
2801 * recursively. If parent or child are NULL, return false */
2802 static bool bdrv_inherits_from_recursive(BlockDriverState
*child
,
2803 BlockDriverState
*parent
)
2805 while (child
&& child
!= parent
) {
2806 child
= child
->inherits_from
;
2809 return child
!= NULL
;
2813 * Return the BdrvChildRole for @bs's backing child. bs->backing is
2814 * mostly used for COW backing children (role = COW), but also for
2815 * filtered children (role = FILTERED | PRIMARY).
2817 static BdrvChildRole
bdrv_backing_role(BlockDriverState
*bs
)
2819 if (bs
->drv
&& bs
->drv
->is_filter
) {
2820 return BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
;
2822 return BDRV_CHILD_COW
;
2827 * Sets the bs->backing link of a BDS. A new reference is created; callers
2828 * which don't need their own reference any more must call bdrv_unref().
2830 int bdrv_set_backing_hd(BlockDriverState
*bs
, BlockDriverState
*backing_hd
,
2834 bool update_inherits_from
= bdrv_chain_contains(bs
, backing_hd
) &&
2835 bdrv_inherits_from_recursive(backing_hd
, bs
);
2837 if (bdrv_is_backing_chain_frozen(bs
, child_bs(bs
->backing
), errp
)) {
2842 bdrv_ref(backing_hd
);
2846 /* Cannot be frozen, we checked that above */
2847 bdrv_unref_child(bs
, bs
->backing
);
2855 bs
->backing
= bdrv_attach_child(bs
, backing_hd
, "backing", &child_of_bds
,
2856 bdrv_backing_role(bs
), errp
);
2862 /* If backing_hd was already part of bs's backing chain, and
2863 * inherits_from pointed recursively to bs then let's update it to
2864 * point directly to bs (else it will become NULL). */
2865 if (update_inherits_from
) {
2866 backing_hd
->inherits_from
= bs
;
2870 bdrv_refresh_limits(bs
, NULL
);
2876 * Opens the backing file for a BlockDriverState if not yet open
2878 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
2879 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
2880 * itself, all options starting with "${bdref_key}." are considered part of the
2883 * TODO Can this be unified with bdrv_open_image()?
2885 int bdrv_open_backing_file(BlockDriverState
*bs
, QDict
*parent_options
,
2886 const char *bdref_key
, Error
**errp
)
2888 char *backing_filename
= NULL
;
2889 char *bdref_key_dot
;
2890 const char *reference
= NULL
;
2892 bool implicit_backing
= false;
2893 BlockDriverState
*backing_hd
;
2895 QDict
*tmp_parent_options
= NULL
;
2896 Error
*local_err
= NULL
;
2898 if (bs
->backing
!= NULL
) {
2902 /* NULL means an empty set of options */
2903 if (parent_options
== NULL
) {
2904 tmp_parent_options
= qdict_new();
2905 parent_options
= tmp_parent_options
;
2908 bs
->open_flags
&= ~BDRV_O_NO_BACKING
;
2910 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
2911 qdict_extract_subqdict(parent_options
, &options
, bdref_key_dot
);
2912 g_free(bdref_key_dot
);
2915 * Caution: while qdict_get_try_str() is fine, getting non-string
2916 * types would require more care. When @parent_options come from
2917 * -blockdev or blockdev_add, its members are typed according to
2918 * the QAPI schema, but when they come from -drive, they're all
2921 reference
= qdict_get_try_str(parent_options
, bdref_key
);
2922 if (reference
|| qdict_haskey(options
, "file.filename")) {
2923 /* keep backing_filename NULL */
2924 } else if (bs
->backing_file
[0] == '\0' && qdict_size(options
) == 0) {
2925 qobject_unref(options
);
2928 if (qdict_size(options
) == 0) {
2929 /* If the user specifies options that do not modify the
2930 * backing file's behavior, we might still consider it the
2931 * implicit backing file. But it's easier this way, and
2932 * just specifying some of the backing BDS's options is
2933 * only possible with -drive anyway (otherwise the QAPI
2934 * schema forces the user to specify everything). */
2935 implicit_backing
= !strcmp(bs
->auto_backing_file
, bs
->backing_file
);
2938 backing_filename
= bdrv_get_full_backing_filename(bs
, &local_err
);
2941 error_propagate(errp
, local_err
);
2942 qobject_unref(options
);
2947 if (!bs
->drv
|| !bs
->drv
->supports_backing
) {
2949 error_setg(errp
, "Driver doesn't support backing files");
2950 qobject_unref(options
);
2955 bs
->backing_format
[0] != '\0' && !qdict_haskey(options
, "driver")) {
2956 qdict_put_str(options
, "driver", bs
->backing_format
);
2959 backing_hd
= bdrv_open_inherit(backing_filename
, reference
, options
, 0, bs
,
2960 &child_of_bds
, bdrv_backing_role(bs
), errp
);
2962 bs
->open_flags
|= BDRV_O_NO_BACKING
;
2963 error_prepend(errp
, "Could not open backing file: ");
2968 if (implicit_backing
) {
2969 bdrv_refresh_filename(backing_hd
);
2970 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
2971 backing_hd
->filename
);
2974 /* Hook up the backing file link; drop our reference, bs owns the
2975 * backing_hd reference now */
2976 bdrv_set_backing_hd(bs
, backing_hd
, &local_err
);
2977 bdrv_unref(backing_hd
);
2979 error_propagate(errp
, local_err
);
2984 qdict_del(parent_options
, bdref_key
);
2987 g_free(backing_filename
);
2988 qobject_unref(tmp_parent_options
);
2992 static BlockDriverState
*
2993 bdrv_open_child_bs(const char *filename
, QDict
*options
, const char *bdref_key
,
2994 BlockDriverState
*parent
, const BdrvChildClass
*child_class
,
2995 BdrvChildRole child_role
, bool allow_none
, Error
**errp
)
2997 BlockDriverState
*bs
= NULL
;
2998 QDict
*image_options
;
2999 char *bdref_key_dot
;
3000 const char *reference
;
3002 assert(child_class
!= NULL
);
3004 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
3005 qdict_extract_subqdict(options
, &image_options
, bdref_key_dot
);
3006 g_free(bdref_key_dot
);
3009 * Caution: while qdict_get_try_str() is fine, getting non-string
3010 * types would require more care. When @options come from
3011 * -blockdev or blockdev_add, its members are typed according to
3012 * the QAPI schema, but when they come from -drive, they're all
3015 reference
= qdict_get_try_str(options
, bdref_key
);
3016 if (!filename
&& !reference
&& !qdict_size(image_options
)) {
3018 error_setg(errp
, "A block device must be specified for \"%s\"",
3021 qobject_unref(image_options
);
3025 bs
= bdrv_open_inherit(filename
, reference
, image_options
, 0,
3026 parent
, child_class
, child_role
, errp
);
3032 qdict_del(options
, bdref_key
);
3037 * Opens a disk image whose options are given as BlockdevRef in another block
3040 * If allow_none is true, no image will be opened if filename is false and no
3041 * BlockdevRef is given. NULL will be returned, but errp remains unset.
3043 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
3044 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
3045 * itself, all options starting with "${bdref_key}." are considered part of the
3048 * The BlockdevRef will be removed from the options QDict.
3050 BdrvChild
*bdrv_open_child(const char *filename
,
3051 QDict
*options
, const char *bdref_key
,
3052 BlockDriverState
*parent
,
3053 const BdrvChildClass
*child_class
,
3054 BdrvChildRole child_role
,
3055 bool allow_none
, Error
**errp
)
3057 BlockDriverState
*bs
;
3059 bs
= bdrv_open_child_bs(filename
, options
, bdref_key
, parent
, child_class
,
3060 child_role
, allow_none
, errp
);
3065 return bdrv_attach_child(parent
, bs
, bdref_key
, child_class
, child_role
,
3070 * TODO Future callers may need to specify parent/child_class in order for
3071 * option inheritance to work. Existing callers use it for the root node.
3073 BlockDriverState
*bdrv_open_blockdev_ref(BlockdevRef
*ref
, Error
**errp
)
3075 BlockDriverState
*bs
= NULL
;
3076 QObject
*obj
= NULL
;
3077 QDict
*qdict
= NULL
;
3078 const char *reference
= NULL
;
3081 if (ref
->type
== QTYPE_QSTRING
) {
3082 reference
= ref
->u
.reference
;
3084 BlockdevOptions
*options
= &ref
->u
.definition
;
3085 assert(ref
->type
== QTYPE_QDICT
);
3087 v
= qobject_output_visitor_new(&obj
);
3088 visit_type_BlockdevOptions(v
, NULL
, &options
, &error_abort
);
3089 visit_complete(v
, &obj
);
3091 qdict
= qobject_to(QDict
, obj
);
3092 qdict_flatten(qdict
);
3094 /* bdrv_open_inherit() defaults to the values in bdrv_flags (for
3095 * compatibility with other callers) rather than what we want as the
3096 * real defaults. Apply the defaults here instead. */
3097 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_DIRECT
, "off");
3098 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_NO_FLUSH
, "off");
3099 qdict_set_default_str(qdict
, BDRV_OPT_READ_ONLY
, "off");
3100 qdict_set_default_str(qdict
, BDRV_OPT_AUTO_READ_ONLY
, "off");
3104 bs
= bdrv_open_inherit(NULL
, reference
, qdict
, 0, NULL
, NULL
, 0, errp
);
3111 static BlockDriverState
*bdrv_append_temp_snapshot(BlockDriverState
*bs
,
3113 QDict
*snapshot_options
,
3116 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
3117 char *tmp_filename
= g_malloc0(PATH_MAX
+ 1);
3119 QemuOpts
*opts
= NULL
;
3120 BlockDriverState
*bs_snapshot
= NULL
;
3123 /* if snapshot, we create a temporary backing file and open it
3124 instead of opening 'filename' directly */
3126 /* Get the required size from the image */
3127 total_size
= bdrv_getlength(bs
);
3128 if (total_size
< 0) {
3129 error_setg_errno(errp
, -total_size
, "Could not get image size");
3133 /* Create the temporary image */
3134 ret
= get_tmp_filename(tmp_filename
, PATH_MAX
+ 1);
3136 error_setg_errno(errp
, -ret
, "Could not get temporary filename");
3140 opts
= qemu_opts_create(bdrv_qcow2
.create_opts
, NULL
, 0,
3142 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, total_size
, &error_abort
);
3143 ret
= bdrv_create(&bdrv_qcow2
, tmp_filename
, opts
, errp
);
3144 qemu_opts_del(opts
);
3146 error_prepend(errp
, "Could not create temporary overlay '%s': ",
3151 /* Prepare options QDict for the temporary file */
3152 qdict_put_str(snapshot_options
, "file.driver", "file");
3153 qdict_put_str(snapshot_options
, "file.filename", tmp_filename
);
3154 qdict_put_str(snapshot_options
, "driver", "qcow2");
3156 bs_snapshot
= bdrv_open(NULL
, NULL
, snapshot_options
, flags
, errp
);
3157 snapshot_options
= NULL
;
3162 /* bdrv_append() consumes a strong reference to bs_snapshot
3163 * (i.e. it will call bdrv_unref() on it) even on error, so in
3164 * order to be able to return one, we have to increase
3165 * bs_snapshot's refcount here */
3166 bdrv_ref(bs_snapshot
);
3167 ret
= bdrv_append(bs_snapshot
, bs
, errp
);
3174 qobject_unref(snapshot_options
);
3175 g_free(tmp_filename
);
3180 * Opens a disk image (raw, qcow2, vmdk, ...)
3182 * options is a QDict of options to pass to the block drivers, or NULL for an
3183 * empty set of options. The reference to the QDict belongs to the block layer
3184 * after the call (even on failure), so if the caller intends to reuse the
3185 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
3187 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
3188 * If it is not NULL, the referenced BDS will be reused.
3190 * The reference parameter may be used to specify an existing block device which
3191 * should be opened. If specified, neither options nor a filename may be given,
3192 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
3194 static BlockDriverState
*bdrv_open_inherit(const char *filename
,
3195 const char *reference
,
3196 QDict
*options
, int flags
,
3197 BlockDriverState
*parent
,
3198 const BdrvChildClass
*child_class
,
3199 BdrvChildRole child_role
,
3203 BlockBackend
*file
= NULL
;
3204 BlockDriverState
*bs
;
3205 BlockDriver
*drv
= NULL
;
3207 const char *drvname
;
3208 const char *backing
;
3209 Error
*local_err
= NULL
;
3210 QDict
*snapshot_options
= NULL
;
3211 int snapshot_flags
= 0;
3213 assert(!child_class
|| !flags
);
3214 assert(!child_class
== !parent
);
3217 bool options_non_empty
= options
? qdict_size(options
) : false;
3218 qobject_unref(options
);
3220 if (filename
|| options_non_empty
) {
3221 error_setg(errp
, "Cannot reference an existing block device with "
3222 "additional options or a new filename");
3226 bs
= bdrv_lookup_bs(reference
, reference
, errp
);
3237 /* NULL means an empty set of options */
3238 if (options
== NULL
) {
3239 options
= qdict_new();
3242 /* json: syntax counts as explicit options, as if in the QDict */
3243 parse_json_protocol(options
, &filename
, &local_err
);
3248 bs
->explicit_options
= qdict_clone_shallow(options
);
3251 bool parent_is_format
;
3254 parent_is_format
= parent
->drv
->is_format
;
3257 * parent->drv is not set yet because this node is opened for
3258 * (potential) format probing. That means that @parent is going
3259 * to be a format node.
3261 parent_is_format
= true;
3264 bs
->inherits_from
= parent
;
3265 child_class
->inherit_options(child_role
, parent_is_format
,
3267 parent
->open_flags
, parent
->options
);
3270 ret
= bdrv_fill_options(&options
, filename
, &flags
, &local_err
);
3276 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
3277 * Caution: getting a boolean member of @options requires care.
3278 * When @options come from -blockdev or blockdev_add, members are
3279 * typed according to the QAPI schema, but when they come from
3280 * -drive, they're all QString.
3282 if (g_strcmp0(qdict_get_try_str(options
, BDRV_OPT_READ_ONLY
), "on") &&
3283 !qdict_get_try_bool(options
, BDRV_OPT_READ_ONLY
, false)) {
3284 flags
|= (BDRV_O_RDWR
| BDRV_O_ALLOW_RDWR
);
3286 flags
&= ~BDRV_O_RDWR
;
3289 if (flags
& BDRV_O_SNAPSHOT
) {
3290 snapshot_options
= qdict_new();
3291 bdrv_temp_snapshot_options(&snapshot_flags
, snapshot_options
,
3293 /* Let bdrv_backing_options() override "read-only" */
3294 qdict_del(options
, BDRV_OPT_READ_ONLY
);
3295 bdrv_inherited_options(BDRV_CHILD_COW
, true,
3296 &flags
, options
, flags
, options
);
3299 bs
->open_flags
= flags
;
3300 bs
->options
= options
;
3301 options
= qdict_clone_shallow(options
);
3303 /* Find the right image format driver */
3304 /* See cautionary note on accessing @options above */
3305 drvname
= qdict_get_try_str(options
, "driver");
3307 drv
= bdrv_find_format(drvname
);
3309 error_setg(errp
, "Unknown driver: '%s'", drvname
);
3314 assert(drvname
|| !(flags
& BDRV_O_PROTOCOL
));
3316 /* See cautionary note on accessing @options above */
3317 backing
= qdict_get_try_str(options
, "backing");
3318 if (qobject_to(QNull
, qdict_get(options
, "backing")) != NULL
||
3319 (backing
&& *backing
== '\0'))
3322 warn_report("Use of \"backing\": \"\" is deprecated; "
3323 "use \"backing\": null instead");
3325 flags
|= BDRV_O_NO_BACKING
;
3326 qdict_del(bs
->explicit_options
, "backing");
3327 qdict_del(bs
->options
, "backing");
3328 qdict_del(options
, "backing");
3331 /* Open image file without format layer. This BlockBackend is only used for
3332 * probing, the block drivers will do their own bdrv_open_child() for the
3333 * same BDS, which is why we put the node name back into options. */
3334 if ((flags
& BDRV_O_PROTOCOL
) == 0) {
3335 BlockDriverState
*file_bs
;
3337 file_bs
= bdrv_open_child_bs(filename
, options
, "file", bs
,
3338 &child_of_bds
, BDRV_CHILD_IMAGE
,
3343 if (file_bs
!= NULL
) {
3344 /* Not requesting BLK_PERM_CONSISTENT_READ because we're only
3345 * looking at the header to guess the image format. This works even
3346 * in cases where a guest would not see a consistent state. */
3347 file
= blk_new(bdrv_get_aio_context(file_bs
), 0, BLK_PERM_ALL
);
3348 blk_insert_bs(file
, file_bs
, &local_err
);
3349 bdrv_unref(file_bs
);
3354 qdict_put_str(options
, "file", bdrv_get_node_name(file_bs
));
3358 /* Image format probing */
3361 ret
= find_image_format(file
, filename
, &drv
, &local_err
);
3366 * This option update would logically belong in bdrv_fill_options(),
3367 * but we first need to open bs->file for the probing to work, while
3368 * opening bs->file already requires the (mostly) final set of options
3369 * so that cache mode etc. can be inherited.
3371 * Adding the driver later is somewhat ugly, but it's not an option
3372 * that would ever be inherited, so it's correct. We just need to make
3373 * sure to update both bs->options (which has the full effective
3374 * options for bs) and options (which has file.* already removed).
3376 qdict_put_str(bs
->options
, "driver", drv
->format_name
);
3377 qdict_put_str(options
, "driver", drv
->format_name
);
3379 error_setg(errp
, "Must specify either driver or file");
3383 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
3384 assert(!!(flags
& BDRV_O_PROTOCOL
) == !!drv
->bdrv_file_open
);
3385 /* file must be NULL if a protocol BDS is about to be created
3386 * (the inverse results in an error message from bdrv_open_common()) */
3387 assert(!(flags
& BDRV_O_PROTOCOL
) || !file
);
3389 /* Open the image */
3390 ret
= bdrv_open_common(bs
, file
, options
, &local_err
);
3400 /* If there is a backing file, use it */
3401 if ((flags
& BDRV_O_NO_BACKING
) == 0) {
3402 ret
= bdrv_open_backing_file(bs
, options
, "backing", &local_err
);
3404 goto close_and_fail
;
3408 /* Remove all children options and references
3409 * from bs->options and bs->explicit_options */
3410 QLIST_FOREACH(child
, &bs
->children
, next
) {
3411 char *child_key_dot
;
3412 child_key_dot
= g_strdup_printf("%s.", child
->name
);
3413 qdict_extract_subqdict(bs
->explicit_options
, NULL
, child_key_dot
);
3414 qdict_extract_subqdict(bs
->options
, NULL
, child_key_dot
);
3415 qdict_del(bs
->explicit_options
, child
->name
);
3416 qdict_del(bs
->options
, child
->name
);
3417 g_free(child_key_dot
);
3420 /* Check if any unknown options were used */
3421 if (qdict_size(options
) != 0) {
3422 const QDictEntry
*entry
= qdict_first(options
);
3423 if (flags
& BDRV_O_PROTOCOL
) {
3424 error_setg(errp
, "Block protocol '%s' doesn't support the option "
3425 "'%s'", drv
->format_name
, entry
->key
);
3428 "Block format '%s' does not support the option '%s'",
3429 drv
->format_name
, entry
->key
);
3432 goto close_and_fail
;
3435 bdrv_parent_cb_change_media(bs
, true);
3437 qobject_unref(options
);
3440 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
3441 * temporary snapshot afterwards. */
3442 if (snapshot_flags
) {
3443 BlockDriverState
*snapshot_bs
;
3444 snapshot_bs
= bdrv_append_temp_snapshot(bs
, snapshot_flags
,
3445 snapshot_options
, &local_err
);
3446 snapshot_options
= NULL
;
3448 goto close_and_fail
;
3450 /* We are not going to return bs but the overlay on top of it
3451 * (snapshot_bs); thus, we have to drop the strong reference to bs
3452 * (which we obtained by calling bdrv_new()). bs will not be deleted,
3453 * though, because the overlay still has a reference to it. */
3462 qobject_unref(snapshot_options
);
3463 qobject_unref(bs
->explicit_options
);
3464 qobject_unref(bs
->options
);
3465 qobject_unref(options
);
3467 bs
->explicit_options
= NULL
;
3469 error_propagate(errp
, local_err
);
3474 qobject_unref(snapshot_options
);
3475 qobject_unref(options
);
3476 error_propagate(errp
, local_err
);
3480 BlockDriverState
*bdrv_open(const char *filename
, const char *reference
,
3481 QDict
*options
, int flags
, Error
**errp
)
3483 return bdrv_open_inherit(filename
, reference
, options
, flags
, NULL
,
3487 /* Return true if the NULL-terminated @list contains @str */
3488 static bool is_str_in_list(const char *str
, const char *const *list
)
3492 for (i
= 0; list
[i
] != NULL
; i
++) {
3493 if (!strcmp(str
, list
[i
])) {
3502 * Check that every option set in @bs->options is also set in
3505 * Options listed in the common_options list and in
3506 * @bs->drv->mutable_opts are skipped.
3508 * Return 0 on success, otherwise return -EINVAL and set @errp.
3510 static int bdrv_reset_options_allowed(BlockDriverState
*bs
,
3511 const QDict
*new_opts
, Error
**errp
)
3513 const QDictEntry
*e
;
3514 /* These options are common to all block drivers and are handled
3515 * in bdrv_reopen_prepare() so they can be left out of @new_opts */
3516 const char *const common_options
[] = {
3517 "node-name", "discard", "cache.direct", "cache.no-flush",
3518 "read-only", "auto-read-only", "detect-zeroes", NULL
3521 for (e
= qdict_first(bs
->options
); e
; e
= qdict_next(bs
->options
, e
)) {
3522 if (!qdict_haskey(new_opts
, e
->key
) &&
3523 !is_str_in_list(e
->key
, common_options
) &&
3524 !is_str_in_list(e
->key
, bs
->drv
->mutable_opts
)) {
3525 error_setg(errp
, "Option '%s' cannot be reset "
3526 "to its default value", e
->key
);
3535 * Returns true if @child can be reached recursively from @bs
3537 static bool bdrv_recurse_has_child(BlockDriverState
*bs
,
3538 BlockDriverState
*child
)
3546 QLIST_FOREACH(c
, &bs
->children
, next
) {
3547 if (bdrv_recurse_has_child(c
->bs
, child
)) {
3556 * Adds a BlockDriverState to a simple queue for an atomic, transactional
3557 * reopen of multiple devices.
3559 * bs_queue can either be an existing BlockReopenQueue that has had QTAILQ_INIT
3560 * already performed, or alternatively may be NULL a new BlockReopenQueue will
3561 * be created and initialized. This newly created BlockReopenQueue should be
3562 * passed back in for subsequent calls that are intended to be of the same
3565 * bs is the BlockDriverState to add to the reopen queue.
3567 * options contains the changed options for the associated bs
3568 * (the BlockReopenQueue takes ownership)
3570 * flags contains the open flags for the associated bs
3572 * returns a pointer to bs_queue, which is either the newly allocated
3573 * bs_queue, or the existing bs_queue being used.
3575 * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple().
3577 static BlockReopenQueue
*bdrv_reopen_queue_child(BlockReopenQueue
*bs_queue
,
3578 BlockDriverState
*bs
,
3580 const BdrvChildClass
*klass
,
3582 bool parent_is_format
,
3583 QDict
*parent_options
,
3589 BlockReopenQueueEntry
*bs_entry
;
3591 QDict
*old_options
, *explicit_options
, *options_copy
;
3595 /* Make sure that the caller remembered to use a drained section. This is
3596 * important to avoid graph changes between the recursive queuing here and
3597 * bdrv_reopen_multiple(). */
3598 assert(bs
->quiesce_counter
> 0);
3600 if (bs_queue
== NULL
) {
3601 bs_queue
= g_new0(BlockReopenQueue
, 1);
3602 QTAILQ_INIT(bs_queue
);
3606 options
= qdict_new();
3609 /* Check if this BlockDriverState is already in the queue */
3610 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
3611 if (bs
== bs_entry
->state
.bs
) {
3617 * Precedence of options:
3618 * 1. Explicitly passed in options (highest)
3619 * 2. Retained from explicitly set options of bs
3620 * 3. Inherited from parent node
3621 * 4. Retained from effective options of bs
3624 /* Old explicitly set values (don't overwrite by inherited value) */
3625 if (bs_entry
|| keep_old_opts
) {
3626 old_options
= qdict_clone_shallow(bs_entry
?
3627 bs_entry
->state
.explicit_options
:
3628 bs
->explicit_options
);
3629 bdrv_join_options(bs
, options
, old_options
);
3630 qobject_unref(old_options
);
3633 explicit_options
= qdict_clone_shallow(options
);
3635 /* Inherit from parent node */
3636 if (parent_options
) {
3638 klass
->inherit_options(role
, parent_is_format
, &flags
, options
,
3639 parent_flags
, parent_options
);
3641 flags
= bdrv_get_flags(bs
);
3644 if (keep_old_opts
) {
3645 /* Old values are used for options that aren't set yet */
3646 old_options
= qdict_clone_shallow(bs
->options
);
3647 bdrv_join_options(bs
, options
, old_options
);
3648 qobject_unref(old_options
);
3651 /* We have the final set of options so let's update the flags */
3652 options_copy
= qdict_clone_shallow(options
);
3653 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
3654 qemu_opts_absorb_qdict(opts
, options_copy
, NULL
);
3655 update_flags_from_options(&flags
, opts
);
3656 qemu_opts_del(opts
);
3657 qobject_unref(options_copy
);
3659 /* bdrv_open_inherit() sets and clears some additional flags internally */
3660 flags
&= ~BDRV_O_PROTOCOL
;
3661 if (flags
& BDRV_O_RDWR
) {
3662 flags
|= BDRV_O_ALLOW_RDWR
;
3666 bs_entry
= g_new0(BlockReopenQueueEntry
, 1);
3667 QTAILQ_INSERT_TAIL(bs_queue
, bs_entry
, entry
);
3669 qobject_unref(bs_entry
->state
.options
);
3670 qobject_unref(bs_entry
->state
.explicit_options
);
3673 bs_entry
->state
.bs
= bs
;
3674 bs_entry
->state
.options
= options
;
3675 bs_entry
->state
.explicit_options
= explicit_options
;
3676 bs_entry
->state
.flags
= flags
;
3678 /* This needs to be overwritten in bdrv_reopen_prepare() */
3679 bs_entry
->state
.perm
= UINT64_MAX
;
3680 bs_entry
->state
.shared_perm
= 0;
3683 * If keep_old_opts is false then it means that unspecified
3684 * options must be reset to their original value. We don't allow
3685 * resetting 'backing' but we need to know if the option is
3686 * missing in order to decide if we have to return an error.
3688 if (!keep_old_opts
) {
3689 bs_entry
->state
.backing_missing
=
3690 !qdict_haskey(options
, "backing") &&
3691 !qdict_haskey(options
, "backing.driver");
3694 QLIST_FOREACH(child
, &bs
->children
, next
) {
3695 QDict
*new_child_options
= NULL
;
3696 bool child_keep_old
= keep_old_opts
;
3698 /* reopen can only change the options of block devices that were
3699 * implicitly created and inherited options. For other (referenced)
3700 * block devices, a syntax like "backing.foo" results in an error. */
3701 if (child
->bs
->inherits_from
!= bs
) {
3705 /* Check if the options contain a child reference */
3706 if (qdict_haskey(options
, child
->name
)) {
3707 const char *childref
= qdict_get_try_str(options
, child
->name
);
3709 * The current child must not be reopened if the child
3710 * reference is null or points to a different node.
3712 if (g_strcmp0(childref
, child
->bs
->node_name
)) {
3716 * If the child reference points to the current child then
3717 * reopen it with its existing set of options (note that
3718 * it can still inherit new options from the parent).
3720 child_keep_old
= true;
3722 /* Extract child options ("child-name.*") */
3723 char *child_key_dot
= g_strdup_printf("%s.", child
->name
);
3724 qdict_extract_subqdict(explicit_options
, NULL
, child_key_dot
);
3725 qdict_extract_subqdict(options
, &new_child_options
, child_key_dot
);
3726 g_free(child_key_dot
);
3729 bdrv_reopen_queue_child(bs_queue
, child
->bs
, new_child_options
,
3730 child
->klass
, child
->role
, bs
->drv
->is_format
,
3731 options
, flags
, child_keep_old
);
3737 BlockReopenQueue
*bdrv_reopen_queue(BlockReopenQueue
*bs_queue
,
3738 BlockDriverState
*bs
,
3739 QDict
*options
, bool keep_old_opts
)
3741 return bdrv_reopen_queue_child(bs_queue
, bs
, options
, NULL
, 0, false,
3742 NULL
, 0, keep_old_opts
);
3746 * Reopen multiple BlockDriverStates atomically & transactionally.
3748 * The queue passed in (bs_queue) must have been built up previous
3749 * via bdrv_reopen_queue().
3751 * Reopens all BDS specified in the queue, with the appropriate
3752 * flags. All devices are prepared for reopen, and failure of any
3753 * device will cause all device changes to be abandoned, and intermediate
3756 * If all devices prepare successfully, then the changes are committed
3759 * All affected nodes must be drained between bdrv_reopen_queue() and
3760 * bdrv_reopen_multiple().
3762 int bdrv_reopen_multiple(BlockReopenQueue
*bs_queue
, Error
**errp
)
3765 BlockReopenQueueEntry
*bs_entry
, *next
;
3767 assert(bs_queue
!= NULL
);
3769 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
3770 assert(bs_entry
->state
.bs
->quiesce_counter
> 0);
3771 if (bdrv_reopen_prepare(&bs_entry
->state
, bs_queue
, errp
)) {
3774 bs_entry
->prepared
= true;
3777 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
3778 BDRVReopenState
*state
= &bs_entry
->state
;
3779 ret
= bdrv_check_perm(state
->bs
, bs_queue
, state
->perm
,
3780 state
->shared_perm
, NULL
, errp
);
3784 /* Check if new_backing_bs would accept the new permissions */
3785 if (state
->replace_backing_bs
&& state
->new_backing_bs
) {
3786 uint64_t nperm
, nshared
;
3787 bdrv_child_perm(state
->bs
, state
->new_backing_bs
,
3788 NULL
, bdrv_backing_role(state
->bs
),
3789 bs_queue
, state
->perm
, state
->shared_perm
,
3791 ret
= bdrv_check_update_perm(state
->new_backing_bs
, NULL
,
3792 nperm
, nshared
, NULL
, errp
);
3797 bs_entry
->perms_checked
= true;
3801 * If we reach this point, we have success and just need to apply the
3804 * Reverse order is used to comfort qcow2 driver: on commit it need to write
3805 * IN_USE flag to the image, to mark bitmaps in the image as invalid. But
3806 * children are usually goes after parents in reopen-queue, so go from last
3809 QTAILQ_FOREACH_REVERSE(bs_entry
, bs_queue
, entry
) {
3810 bdrv_reopen_commit(&bs_entry
->state
);
3815 QTAILQ_FOREACH_SAFE(bs_entry
, bs_queue
, entry
, next
) {
3816 BDRVReopenState
*state
= &bs_entry
->state
;
3818 if (!bs_entry
->perms_checked
) {
3823 uint64_t perm
, shared
;
3825 bdrv_get_cumulative_perm(state
->bs
, &perm
, &shared
);
3826 assert(perm
== state
->perm
);
3827 assert(shared
== state
->shared_perm
);
3829 bdrv_set_perm(state
->bs
);
3831 bdrv_abort_perm_update(state
->bs
);
3832 if (state
->replace_backing_bs
&& state
->new_backing_bs
) {
3833 bdrv_abort_perm_update(state
->new_backing_bs
);
3839 QTAILQ_FOREACH_REVERSE(bs_entry
, bs_queue
, entry
) {
3840 BlockDriverState
*bs
= bs_entry
->state
.bs
;
3842 if (bs
->drv
->bdrv_reopen_commit_post
)
3843 bs
->drv
->bdrv_reopen_commit_post(&bs_entry
->state
);
3847 QTAILQ_FOREACH_SAFE(bs_entry
, bs_queue
, entry
, next
) {
3849 if (bs_entry
->prepared
) {
3850 bdrv_reopen_abort(&bs_entry
->state
);
3852 qobject_unref(bs_entry
->state
.explicit_options
);
3853 qobject_unref(bs_entry
->state
.options
);
3855 if (bs_entry
->state
.new_backing_bs
) {
3856 bdrv_unref(bs_entry
->state
.new_backing_bs
);
3865 int bdrv_reopen_set_read_only(BlockDriverState
*bs
, bool read_only
,
3869 BlockReopenQueue
*queue
;
3870 QDict
*opts
= qdict_new();
3872 qdict_put_bool(opts
, BDRV_OPT_READ_ONLY
, read_only
);
3874 bdrv_subtree_drained_begin(bs
);
3875 queue
= bdrv_reopen_queue(NULL
, bs
, opts
, true);
3876 ret
= bdrv_reopen_multiple(queue
, errp
);
3877 bdrv_subtree_drained_end(bs
);
3882 static BlockReopenQueueEntry
*find_parent_in_reopen_queue(BlockReopenQueue
*q
,
3885 BlockReopenQueueEntry
*entry
;
3887 QTAILQ_FOREACH(entry
, q
, entry
) {
3888 BlockDriverState
*bs
= entry
->state
.bs
;
3891 QLIST_FOREACH(child
, &bs
->children
, next
) {
3901 static void bdrv_reopen_perm(BlockReopenQueue
*q
, BlockDriverState
*bs
,
3902 uint64_t *perm
, uint64_t *shared
)
3905 BlockReopenQueueEntry
*parent
;
3906 uint64_t cumulative_perms
= 0;
3907 uint64_t cumulative_shared_perms
= BLK_PERM_ALL
;
3909 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
3910 parent
= find_parent_in_reopen_queue(q
, c
);
3912 cumulative_perms
|= c
->perm
;
3913 cumulative_shared_perms
&= c
->shared_perm
;
3915 uint64_t nperm
, nshared
;
3917 bdrv_child_perm(parent
->state
.bs
, bs
, c
, c
->role
, q
,
3918 parent
->state
.perm
, parent
->state
.shared_perm
,
3921 cumulative_perms
|= nperm
;
3922 cumulative_shared_perms
&= nshared
;
3925 *perm
= cumulative_perms
;
3926 *shared
= cumulative_shared_perms
;
3929 static bool bdrv_reopen_can_attach(BlockDriverState
*parent
,
3931 BlockDriverState
*new_child
,
3934 AioContext
*parent_ctx
= bdrv_get_aio_context(parent
);
3935 AioContext
*child_ctx
= bdrv_get_aio_context(new_child
);
3939 ignore
= g_slist_prepend(NULL
, child
);
3940 ret
= bdrv_can_set_aio_context(new_child
, parent_ctx
, &ignore
, NULL
);
3941 g_slist_free(ignore
);
3946 ignore
= g_slist_prepend(NULL
, child
);
3947 ret
= bdrv_can_set_aio_context(parent
, child_ctx
, &ignore
, errp
);
3948 g_slist_free(ignore
);
3953 * Take a BDRVReopenState and check if the value of 'backing' in the
3954 * reopen_state->options QDict is valid or not.
3956 * If 'backing' is missing from the QDict then return 0.
3958 * If 'backing' contains the node name of the backing file of
3959 * reopen_state->bs then return 0.
3961 * If 'backing' contains a different node name (or is null) then check
3962 * whether the current backing file can be replaced with the new one.
3963 * If that's the case then reopen_state->replace_backing_bs is set to
3964 * true and reopen_state->new_backing_bs contains a pointer to the new
3965 * backing BlockDriverState (or NULL).
3967 * Return 0 on success, otherwise return < 0 and set @errp.
3969 static int bdrv_reopen_parse_backing(BDRVReopenState
*reopen_state
,
3972 BlockDriverState
*bs
= reopen_state
->bs
;
3973 BlockDriverState
*overlay_bs
, *below_bs
, *new_backing_bs
;
3977 value
= qdict_get(reopen_state
->options
, "backing");
3978 if (value
== NULL
) {
3982 switch (qobject_type(value
)) {
3984 new_backing_bs
= NULL
;
3987 str
= qstring_get_str(qobject_to(QString
, value
));
3988 new_backing_bs
= bdrv_lookup_bs(NULL
, str
, errp
);
3989 if (new_backing_bs
== NULL
) {
3991 } else if (bdrv_recurse_has_child(new_backing_bs
, bs
)) {
3992 error_setg(errp
, "Making '%s' a backing file of '%s' "
3993 "would create a cycle", str
, bs
->node_name
);
3998 /* 'backing' does not allow any other data type */
3999 g_assert_not_reached();
4003 * Check AioContext compatibility so that the bdrv_set_backing_hd() call in
4004 * bdrv_reopen_commit() won't fail.
4006 if (new_backing_bs
) {
4007 if (!bdrv_reopen_can_attach(bs
, bs
->backing
, new_backing_bs
, errp
)) {
4013 * Ensure that @bs can really handle backing files, because we are
4014 * about to give it one (or swap the existing one)
4016 if (bs
->drv
->is_filter
) {
4017 /* Filters always have a file or a backing child */
4019 error_setg(errp
, "'%s' is a %s filter node that does not support a "
4020 "backing child", bs
->node_name
, bs
->drv
->format_name
);
4023 } else if (!bs
->drv
->supports_backing
) {
4024 error_setg(errp
, "Driver '%s' of node '%s' does not support backing "
4025 "files", bs
->drv
->format_name
, bs
->node_name
);
4030 * Find the "actual" backing file by skipping all links that point
4031 * to an implicit node, if any (e.g. a commit filter node).
4032 * We cannot use any of the bdrv_skip_*() functions here because
4033 * those return the first explicit node, while we are looking for
4037 for (below_bs
= bdrv_filter_or_cow_bs(overlay_bs
);
4038 below_bs
&& below_bs
->implicit
;
4039 below_bs
= bdrv_filter_or_cow_bs(overlay_bs
))
4041 overlay_bs
= below_bs
;
4044 /* If we want to replace the backing file we need some extra checks */
4045 if (new_backing_bs
!= bdrv_filter_or_cow_bs(overlay_bs
)) {
4046 /* Check for implicit nodes between bs and its backing file */
4047 if (bs
!= overlay_bs
) {
4048 error_setg(errp
, "Cannot change backing link if '%s' has "
4049 "an implicit backing file", bs
->node_name
);
4053 * Check if the backing link that we want to replace is frozen.
4055 * bdrv_filter_or_cow_child(overlay_bs) == overlay_bs->backing,
4056 * because we know that overlay_bs == bs, and that @bs
4057 * either is a filter that uses ->backing or a COW format BDS
4058 * with bs->drv->supports_backing == true.
4060 if (bdrv_is_backing_chain_frozen(overlay_bs
,
4061 child_bs(overlay_bs
->backing
), errp
))
4065 reopen_state
->replace_backing_bs
= true;
4066 if (new_backing_bs
) {
4067 bdrv_ref(new_backing_bs
);
4068 reopen_state
->new_backing_bs
= new_backing_bs
;
4076 * Prepares a BlockDriverState for reopen. All changes are staged in the
4077 * 'opaque' field of the BDRVReopenState, which is used and allocated by
4078 * the block driver layer .bdrv_reopen_prepare()
4080 * bs is the BlockDriverState to reopen
4081 * flags are the new open flags
4082 * queue is the reopen queue
4084 * Returns 0 on success, non-zero on error. On error errp will be set
4087 * On failure, bdrv_reopen_abort() will be called to clean up any data.
4088 * It is the responsibility of the caller to then call the abort() or
4089 * commit() for any other BDS that have been left in a prepare() state
4092 int bdrv_reopen_prepare(BDRVReopenState
*reopen_state
, BlockReopenQueue
*queue
,
4097 Error
*local_err
= NULL
;
4100 QDict
*orig_reopen_opts
;
4101 char *discard
= NULL
;
4103 bool drv_prepared
= false;
4105 assert(reopen_state
!= NULL
);
4106 assert(reopen_state
->bs
->drv
!= NULL
);
4107 drv
= reopen_state
->bs
->drv
;
4109 /* This function and each driver's bdrv_reopen_prepare() remove
4110 * entries from reopen_state->options as they are processed, so
4111 * we need to make a copy of the original QDict. */
4112 orig_reopen_opts
= qdict_clone_shallow(reopen_state
->options
);
4114 /* Process generic block layer options */
4115 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
4116 if (!qemu_opts_absorb_qdict(opts
, reopen_state
->options
, errp
)) {
4121 /* This was already called in bdrv_reopen_queue_child() so the flags
4122 * are up-to-date. This time we simply want to remove the options from
4123 * QemuOpts in order to indicate that they have been processed. */
4124 old_flags
= reopen_state
->flags
;
4125 update_flags_from_options(&reopen_state
->flags
, opts
);
4126 assert(old_flags
== reopen_state
->flags
);
4128 discard
= qemu_opt_get_del(opts
, BDRV_OPT_DISCARD
);
4129 if (discard
!= NULL
) {
4130 if (bdrv_parse_discard_flags(discard
, &reopen_state
->flags
) != 0) {
4131 error_setg(errp
, "Invalid discard option");
4137 reopen_state
->detect_zeroes
=
4138 bdrv_parse_detect_zeroes(opts
, reopen_state
->flags
, &local_err
);
4140 error_propagate(errp
, local_err
);
4145 /* All other options (including node-name and driver) must be unchanged.
4146 * Put them back into the QDict, so that they are checked at the end
4147 * of this function. */
4148 qemu_opts_to_qdict(opts
, reopen_state
->options
);
4150 /* If we are to stay read-only, do not allow permission change
4151 * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is
4152 * not set, or if the BDS still has copy_on_read enabled */
4153 read_only
= !(reopen_state
->flags
& BDRV_O_RDWR
);
4154 ret
= bdrv_can_set_read_only(reopen_state
->bs
, read_only
, true, &local_err
);
4156 error_propagate(errp
, local_err
);
4160 /* Calculate required permissions after reopening */
4161 bdrv_reopen_perm(queue
, reopen_state
->bs
,
4162 &reopen_state
->perm
, &reopen_state
->shared_perm
);
4164 ret
= bdrv_flush(reopen_state
->bs
);
4166 error_setg_errno(errp
, -ret
, "Error flushing drive");
4170 if (drv
->bdrv_reopen_prepare
) {
4172 * If a driver-specific option is missing, it means that we
4173 * should reset it to its default value.
4174 * But not all options allow that, so we need to check it first.
4176 ret
= bdrv_reset_options_allowed(reopen_state
->bs
,
4177 reopen_state
->options
, errp
);
4182 ret
= drv
->bdrv_reopen_prepare(reopen_state
, queue
, &local_err
);
4184 if (local_err
!= NULL
) {
4185 error_propagate(errp
, local_err
);
4187 bdrv_refresh_filename(reopen_state
->bs
);
4188 error_setg(errp
, "failed while preparing to reopen image '%s'",
4189 reopen_state
->bs
->filename
);
4194 /* It is currently mandatory to have a bdrv_reopen_prepare()
4195 * handler for each supported drv. */
4196 error_setg(errp
, "Block format '%s' used by node '%s' "
4197 "does not support reopening files", drv
->format_name
,
4198 bdrv_get_device_or_node_name(reopen_state
->bs
));
4203 drv_prepared
= true;
4206 * We must provide the 'backing' option if the BDS has a backing
4207 * file or if the image file has a backing file name as part of
4208 * its metadata. Otherwise the 'backing' option can be omitted.
4210 if (drv
->supports_backing
&& reopen_state
->backing_missing
&&
4211 (reopen_state
->bs
->backing
|| reopen_state
->bs
->backing_file
[0])) {
4212 error_setg(errp
, "backing is missing for '%s'",
4213 reopen_state
->bs
->node_name
);
4219 * Allow changing the 'backing' option. The new value can be
4220 * either a reference to an existing node (using its node name)
4221 * or NULL to simply detach the current backing file.
4223 ret
= bdrv_reopen_parse_backing(reopen_state
, errp
);
4227 qdict_del(reopen_state
->options
, "backing");
4229 /* Options that are not handled are only okay if they are unchanged
4230 * compared to the old state. It is expected that some options are only
4231 * used for the initial open, but not reopen (e.g. filename) */
4232 if (qdict_size(reopen_state
->options
)) {
4233 const QDictEntry
*entry
= qdict_first(reopen_state
->options
);
4236 QObject
*new = entry
->value
;
4237 QObject
*old
= qdict_get(reopen_state
->bs
->options
, entry
->key
);
4239 /* Allow child references (child_name=node_name) as long as they
4240 * point to the current child (i.e. everything stays the same). */
4241 if (qobject_type(new) == QTYPE_QSTRING
) {
4243 QLIST_FOREACH(child
, &reopen_state
->bs
->children
, next
) {
4244 if (!strcmp(child
->name
, entry
->key
)) {
4250 if (!strcmp(child
->bs
->node_name
,
4251 qstring_get_str(qobject_to(QString
, new)))) {
4252 continue; /* Found child with this name, skip option */
4258 * TODO: When using -drive to specify blockdev options, all values
4259 * will be strings; however, when using -blockdev, blockdev-add or
4260 * filenames using the json:{} pseudo-protocol, they will be
4262 * In contrast, reopening options are (currently) always strings
4263 * (because you can only specify them through qemu-io; all other
4264 * callers do not specify any options).
4265 * Therefore, when using anything other than -drive to create a BDS,
4266 * this cannot detect non-string options as unchanged, because
4267 * qobject_is_equal() always returns false for objects of different
4268 * type. In the future, this should be remedied by correctly typing
4269 * all options. For now, this is not too big of an issue because
4270 * the user can simply omit options which cannot be changed anyway,
4271 * so they will stay unchanged.
4273 if (!qobject_is_equal(new, old
)) {
4274 error_setg(errp
, "Cannot change the option '%s'", entry
->key
);
4278 } while ((entry
= qdict_next(reopen_state
->options
, entry
)));
4283 /* Restore the original reopen_state->options QDict */
4284 qobject_unref(reopen_state
->options
);
4285 reopen_state
->options
= qobject_ref(orig_reopen_opts
);
4288 if (ret
< 0 && drv_prepared
) {
4289 /* drv->bdrv_reopen_prepare() has succeeded, so we need to
4290 * call drv->bdrv_reopen_abort() before signaling an error
4291 * (bdrv_reopen_multiple() will not call bdrv_reopen_abort()
4292 * when the respective bdrv_reopen_prepare() has failed) */
4293 if (drv
->bdrv_reopen_abort
) {
4294 drv
->bdrv_reopen_abort(reopen_state
);
4297 qemu_opts_del(opts
);
4298 qobject_unref(orig_reopen_opts
);
4304 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
4305 * makes them final by swapping the staging BlockDriverState contents into
4306 * the active BlockDriverState contents.
4308 void bdrv_reopen_commit(BDRVReopenState
*reopen_state
)
4311 BlockDriverState
*bs
;
4314 assert(reopen_state
!= NULL
);
4315 bs
= reopen_state
->bs
;
4317 assert(drv
!= NULL
);
4319 /* If there are any driver level actions to take */
4320 if (drv
->bdrv_reopen_commit
) {
4321 drv
->bdrv_reopen_commit(reopen_state
);
4324 /* set BDS specific flags now */
4325 qobject_unref(bs
->explicit_options
);
4326 qobject_unref(bs
->options
);
4328 bs
->explicit_options
= reopen_state
->explicit_options
;
4329 bs
->options
= reopen_state
->options
;
4330 bs
->open_flags
= reopen_state
->flags
;
4331 bs
->read_only
= !(reopen_state
->flags
& BDRV_O_RDWR
);
4332 bs
->detect_zeroes
= reopen_state
->detect_zeroes
;
4334 if (reopen_state
->replace_backing_bs
) {
4335 qdict_del(bs
->explicit_options
, "backing");
4336 qdict_del(bs
->options
, "backing");
4339 /* Remove child references from bs->options and bs->explicit_options.
4340 * Child options were already removed in bdrv_reopen_queue_child() */
4341 QLIST_FOREACH(child
, &bs
->children
, next
) {
4342 qdict_del(bs
->explicit_options
, child
->name
);
4343 qdict_del(bs
->options
, child
->name
);
4347 * Change the backing file if a new one was specified. We do this
4348 * after updating bs->options, so bdrv_refresh_filename() (called
4349 * from bdrv_set_backing_hd()) has the new values.
4351 if (reopen_state
->replace_backing_bs
) {
4352 BlockDriverState
*old_backing_bs
= child_bs(bs
->backing
);
4353 assert(!old_backing_bs
|| !old_backing_bs
->implicit
);
4354 /* Abort the permission update on the backing bs we're detaching */
4355 if (old_backing_bs
) {
4356 bdrv_abort_perm_update(old_backing_bs
);
4358 bdrv_set_backing_hd(bs
, reopen_state
->new_backing_bs
, &error_abort
);
4361 bdrv_refresh_limits(bs
, NULL
);
4365 * Abort the reopen, and delete and free the staged changes in
4368 void bdrv_reopen_abort(BDRVReopenState
*reopen_state
)
4372 assert(reopen_state
!= NULL
);
4373 drv
= reopen_state
->bs
->drv
;
4374 assert(drv
!= NULL
);
4376 if (drv
->bdrv_reopen_abort
) {
4377 drv
->bdrv_reopen_abort(reopen_state
);
4382 static void bdrv_close(BlockDriverState
*bs
)
4384 BdrvAioNotifier
*ban
, *ban_next
;
4385 BdrvChild
*child
, *next
;
4387 assert(!bs
->refcnt
);
4389 bdrv_drained_begin(bs
); /* complete I/O */
4391 bdrv_drain(bs
); /* in case flush left pending I/O */
4394 if (bs
->drv
->bdrv_close
) {
4395 /* Must unfreeze all children, so bdrv_unref_child() works */
4396 bs
->drv
->bdrv_close(bs
);
4401 QLIST_FOREACH_SAFE(child
, &bs
->children
, next
, next
) {
4402 bdrv_unref_child(bs
, child
);
4409 qatomic_set(&bs
->copy_on_read
, 0);
4410 bs
->backing_file
[0] = '\0';
4411 bs
->backing_format
[0] = '\0';
4412 bs
->total_sectors
= 0;
4413 bs
->encrypted
= false;
4415 qobject_unref(bs
->options
);
4416 qobject_unref(bs
->explicit_options
);
4418 bs
->explicit_options
= NULL
;
4419 qobject_unref(bs
->full_open_options
);
4420 bs
->full_open_options
= NULL
;
4422 bdrv_release_named_dirty_bitmaps(bs
);
4423 assert(QLIST_EMPTY(&bs
->dirty_bitmaps
));
4425 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_next
) {
4428 QLIST_INIT(&bs
->aio_notifiers
);
4429 bdrv_drained_end(bs
);
4432 * If we're still inside some bdrv_drain_all_begin()/end() sections, end
4433 * them now since this BDS won't exist anymore when bdrv_drain_all_end()
4436 if (bs
->quiesce_counter
) {
4437 bdrv_drain_all_end_quiesce(bs
);
4441 void bdrv_close_all(void)
4443 assert(job_next(NULL
) == NULL
);
4445 /* Drop references from requests still in flight, such as canceled block
4446 * jobs whose AIO context has not been polled yet */
4449 blk_remove_all_bs();
4450 blockdev_close_all_bdrv_states();
4452 assert(QTAILQ_EMPTY(&all_bdrv_states
));
4455 static bool should_update_child(BdrvChild
*c
, BlockDriverState
*to
)
4461 if (c
->klass
->stay_at_node
) {
4465 /* If the child @c belongs to the BDS @to, replacing the current
4466 * c->bs by @to would mean to create a loop.
4468 * Such a case occurs when appending a BDS to a backing chain.
4469 * For instance, imagine the following chain:
4471 * guest device -> node A -> further backing chain...
4473 * Now we create a new BDS B which we want to put on top of this
4474 * chain, so we first attach A as its backing node:
4479 * guest device -> node A -> further backing chain...
4481 * Finally we want to replace A by B. When doing that, we want to
4482 * replace all pointers to A by pointers to B -- except for the
4483 * pointer from B because (1) that would create a loop, and (2)
4484 * that pointer should simply stay intact:
4486 * guest device -> node B
4489 * node A -> further backing chain...
4491 * In general, when replacing a node A (c->bs) by a node B (@to),
4492 * if A is a child of B, that means we cannot replace A by B there
4493 * because that would create a loop. Silently detaching A from B
4494 * is also not really an option. So overall just leaving A in
4495 * place there is the most sensible choice.
4497 * We would also create a loop in any cases where @c is only
4498 * indirectly referenced by @to. Prevent this by returning false
4499 * if @c is found (by breadth-first search) anywhere in the whole
4504 found
= g_hash_table_new(NULL
, NULL
);
4505 g_hash_table_add(found
, to
);
4506 queue
= g_queue_new();
4507 g_queue_push_tail(queue
, to
);
4509 while (!g_queue_is_empty(queue
)) {
4510 BlockDriverState
*v
= g_queue_pop_head(queue
);
4513 QLIST_FOREACH(c2
, &v
->children
, next
) {
4519 if (g_hash_table_contains(found
, c2
->bs
)) {
4523 g_queue_push_tail(queue
, c2
->bs
);
4524 g_hash_table_add(found
, c2
->bs
);
4528 g_queue_free(queue
);
4529 g_hash_table_destroy(found
);
4535 * With auto_skip=true bdrv_replace_node_common skips updating from parents
4536 * if it creates a parent-child relation loop or if parent is block-job.
4538 * With auto_skip=false the error is returned if from has a parent which should
4541 static int bdrv_replace_node_common(BlockDriverState
*from
,
4542 BlockDriverState
*to
,
4543 bool auto_skip
, Error
**errp
)
4545 BdrvChild
*c
, *next
;
4546 GSList
*list
= NULL
, *p
;
4547 uint64_t perm
= 0, shared
= BLK_PERM_ALL
;
4550 /* Make sure that @from doesn't go away until we have successfully attached
4551 * all of its parents to @to. */
4554 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
4555 assert(bdrv_get_aio_context(from
) == bdrv_get_aio_context(to
));
4556 bdrv_drained_begin(from
);
4558 /* Put all parents into @list and calculate their cumulative permissions */
4559 QLIST_FOREACH_SAFE(c
, &from
->parents
, next_parent
, next
) {
4560 assert(c
->bs
== from
);
4561 if (!should_update_child(c
, to
)) {
4566 error_setg(errp
, "Should not change '%s' link to '%s'",
4567 c
->name
, from
->node_name
);
4572 error_setg(errp
, "Cannot change '%s' link to '%s'",
4573 c
->name
, from
->node_name
);
4576 list
= g_slist_prepend(list
, c
);
4578 shared
&= c
->shared_perm
;
4581 /* Check whether the required permissions can be granted on @to, ignoring
4582 * all BdrvChild in @list so that they can't block themselves. */
4583 ret
= bdrv_check_update_perm(to
, NULL
, perm
, shared
, list
, errp
);
4585 bdrv_abort_perm_update(to
);
4589 /* Now actually perform the change. We performed the permission check for
4590 * all elements of @list at once, so set the permissions all at once at the
4592 for (p
= list
; p
!= NULL
; p
= p
->next
) {
4596 bdrv_replace_child_noperm(c
, to
);
4606 bdrv_drained_end(from
);
4612 int bdrv_replace_node(BlockDriverState
*from
, BlockDriverState
*to
,
4615 return bdrv_replace_node_common(from
, to
, true, errp
);
4619 * Add new bs contents at the top of an image chain while the chain is
4620 * live, while keeping required fields on the top layer.
4622 * This will modify the BlockDriverState fields, and swap contents
4623 * between bs_new and bs_top. Both bs_new and bs_top are modified.
4625 * bs_new must not be attached to a BlockBackend.
4627 * This function does not create any image files.
4629 * bdrv_append() takes ownership of a bs_new reference and unrefs it because
4630 * that's what the callers commonly need. bs_new will be referenced by the old
4631 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a
4632 * reference of its own, it must call bdrv_ref().
4634 int bdrv_append(BlockDriverState
*bs_new
, BlockDriverState
*bs_top
,
4637 int ret
= bdrv_set_backing_hd(bs_new
, bs_top
, errp
);
4642 ret
= bdrv_replace_node(bs_top
, bs_new
, errp
);
4644 bdrv_set_backing_hd(bs_new
, NULL
, &error_abort
);
4652 * bs_new is now referenced by its new parents, we don't need the
4653 * additional reference any more.
4660 static void bdrv_delete(BlockDriverState
*bs
)
4662 assert(bdrv_op_blocker_is_empty(bs
));
4663 assert(!bs
->refcnt
);
4665 /* remove from list, if necessary */
4666 if (bs
->node_name
[0] != '\0') {
4667 QTAILQ_REMOVE(&graph_bdrv_states
, bs
, node_list
);
4669 QTAILQ_REMOVE(&all_bdrv_states
, bs
, bs_list
);
4676 BlockDriverState
*bdrv_insert_node(BlockDriverState
*bs
, QDict
*node_options
,
4677 int flags
, Error
**errp
)
4679 BlockDriverState
*new_node_bs
;
4680 Error
*local_err
= NULL
;
4682 new_node_bs
= bdrv_open(NULL
, NULL
, node_options
, flags
, errp
);
4683 if (new_node_bs
== NULL
) {
4684 error_prepend(errp
, "Could not create node: ");
4688 bdrv_drained_begin(bs
);
4689 bdrv_replace_node(bs
, new_node_bs
, &local_err
);
4690 bdrv_drained_end(bs
);
4693 bdrv_unref(new_node_bs
);
4694 error_propagate(errp
, local_err
);
4702 * Run consistency checks on an image
4704 * Returns 0 if the check could be completed (it doesn't mean that the image is
4705 * free of errors) or -errno when an internal error occurred. The results of the
4706 * check are stored in res.
4708 int coroutine_fn
bdrv_co_check(BlockDriverState
*bs
,
4709 BdrvCheckResult
*res
, BdrvCheckMode fix
)
4711 if (bs
->drv
== NULL
) {
4714 if (bs
->drv
->bdrv_co_check
== NULL
) {
4718 memset(res
, 0, sizeof(*res
));
4719 return bs
->drv
->bdrv_co_check(bs
, res
, fix
);
4725 * -EINVAL - backing format specified, but no file
4726 * -ENOSPC - can't update the backing file because no space is left in the
4728 * -ENOTSUP - format driver doesn't support changing the backing file
4730 int bdrv_change_backing_file(BlockDriverState
*bs
, const char *backing_file
,
4731 const char *backing_fmt
, bool warn
)
4733 BlockDriver
*drv
= bs
->drv
;
4740 /* Backing file format doesn't make sense without a backing file */
4741 if (backing_fmt
&& !backing_file
) {
4745 if (warn
&& backing_file
&& !backing_fmt
) {
4746 warn_report("Deprecated use of backing file without explicit "
4747 "backing format, use of this image requires "
4748 "potentially unsafe format probing");
4751 if (drv
->bdrv_change_backing_file
!= NULL
) {
4752 ret
= drv
->bdrv_change_backing_file(bs
, backing_file
, backing_fmt
);
4758 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
), backing_file
?: "");
4759 pstrcpy(bs
->backing_format
, sizeof(bs
->backing_format
), backing_fmt
?: "");
4760 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
4761 backing_file
?: "");
4767 * Finds the first non-filter node above bs in the chain between
4768 * active and bs. The returned node is either an immediate parent of
4769 * bs, or there are only filter nodes between the two.
4771 * Returns NULL if bs is not found in active's image chain,
4772 * or if active == bs.
4774 * Returns the bottommost base image if bs == NULL.
4776 BlockDriverState
*bdrv_find_overlay(BlockDriverState
*active
,
4777 BlockDriverState
*bs
)
4779 bs
= bdrv_skip_filters(bs
);
4780 active
= bdrv_skip_filters(active
);
4783 BlockDriverState
*next
= bdrv_backing_chain_next(active
);
4793 /* Given a BDS, searches for the base layer. */
4794 BlockDriverState
*bdrv_find_base(BlockDriverState
*bs
)
4796 return bdrv_find_overlay(bs
, NULL
);
4800 * Return true if at least one of the COW (backing) and filter links
4801 * between @bs and @base is frozen. @errp is set if that's the case.
4802 * @base must be reachable from @bs, or NULL.
4804 bool bdrv_is_backing_chain_frozen(BlockDriverState
*bs
, BlockDriverState
*base
,
4807 BlockDriverState
*i
;
4810 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
4811 child
= bdrv_filter_or_cow_child(i
);
4813 if (child
&& child
->frozen
) {
4814 error_setg(errp
, "Cannot change '%s' link from '%s' to '%s'",
4815 child
->name
, i
->node_name
, child
->bs
->node_name
);
4824 * Freeze all COW (backing) and filter links between @bs and @base.
4825 * If any of the links is already frozen the operation is aborted and
4826 * none of the links are modified.
4827 * @base must be reachable from @bs, or NULL.
4828 * Returns 0 on success. On failure returns < 0 and sets @errp.
4830 int bdrv_freeze_backing_chain(BlockDriverState
*bs
, BlockDriverState
*base
,
4833 BlockDriverState
*i
;
4836 if (bdrv_is_backing_chain_frozen(bs
, base
, errp
)) {
4840 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
4841 child
= bdrv_filter_or_cow_child(i
);
4842 if (child
&& child
->bs
->never_freeze
) {
4843 error_setg(errp
, "Cannot freeze '%s' link to '%s'",
4844 child
->name
, child
->bs
->node_name
);
4849 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
4850 child
= bdrv_filter_or_cow_child(i
);
4852 child
->frozen
= true;
4860 * Unfreeze all COW (backing) and filter links between @bs and @base.
4861 * The caller must ensure that all links are frozen before using this
4863 * @base must be reachable from @bs, or NULL.
4865 void bdrv_unfreeze_backing_chain(BlockDriverState
*bs
, BlockDriverState
*base
)
4867 BlockDriverState
*i
;
4870 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
4871 child
= bdrv_filter_or_cow_child(i
);
4873 assert(child
->frozen
);
4874 child
->frozen
= false;
4880 * Drops images above 'base' up to and including 'top', and sets the image
4881 * above 'top' to have base as its backing file.
4883 * Requires that the overlay to 'top' is opened r/w, so that the backing file
4884 * information in 'bs' can be properly updated.
4886 * E.g., this will convert the following chain:
4887 * bottom <- base <- intermediate <- top <- active
4891 * bottom <- base <- active
4893 * It is allowed for bottom==base, in which case it converts:
4895 * base <- intermediate <- top <- active
4901 * If backing_file_str is non-NULL, it will be used when modifying top's
4902 * overlay image metadata.
4905 * if active == top, that is considered an error
4908 int bdrv_drop_intermediate(BlockDriverState
*top
, BlockDriverState
*base
,
4909 const char *backing_file_str
)
4911 BlockDriverState
*explicit_top
= top
;
4912 bool update_inherits_from
;
4914 Error
*local_err
= NULL
;
4916 g_autoptr(GSList
) updated_children
= NULL
;
4920 bdrv_subtree_drained_begin(top
);
4922 if (!top
->drv
|| !base
->drv
) {
4926 /* Make sure that base is in the backing chain of top */
4927 if (!bdrv_chain_contains(top
, base
)) {
4931 /* If 'base' recursively inherits from 'top' then we should set
4932 * base->inherits_from to top->inherits_from after 'top' and all
4933 * other intermediate nodes have been dropped.
4934 * If 'top' is an implicit node (e.g. "commit_top") we should skip
4935 * it because no one inherits from it. We use explicit_top for that. */
4936 explicit_top
= bdrv_skip_implicit_filters(explicit_top
);
4937 update_inherits_from
= bdrv_inherits_from_recursive(base
, explicit_top
);
4939 /* success - we can delete the intermediate states, and link top->base */
4940 /* TODO Check graph modification op blockers (BLK_PERM_GRAPH_MOD) once
4941 * we've figured out how they should work. */
4942 if (!backing_file_str
) {
4943 bdrv_refresh_filename(base
);
4944 backing_file_str
= base
->filename
;
4947 QLIST_FOREACH(c
, &top
->parents
, next_parent
) {
4948 updated_children
= g_slist_prepend(updated_children
, c
);
4951 bdrv_replace_node_common(top
, base
, false, &local_err
);
4953 error_report_err(local_err
);
4957 for (p
= updated_children
; p
; p
= p
->next
) {
4960 if (c
->klass
->update_filename
) {
4961 ret
= c
->klass
->update_filename(c
, base
, backing_file_str
,
4965 * TODO: Actually, we want to rollback all previous iterations
4966 * of this loop, and (which is almost impossible) previous
4967 * bdrv_replace_node()...
4969 * Note, that c->klass->update_filename may lead to permission
4970 * update, so it's a bad idea to call it inside permission
4971 * update transaction of bdrv_replace_node.
4973 error_report_err(local_err
);
4979 if (update_inherits_from
) {
4980 base
->inherits_from
= explicit_top
->inherits_from
;
4985 bdrv_subtree_drained_end(top
);
4991 * Implementation of BlockDriver.bdrv_get_allocated_file_size() that
4992 * sums the size of all data-bearing children. (This excludes backing
4995 static int64_t bdrv_sum_allocated_file_size(BlockDriverState
*bs
)
4998 int64_t child_size
, sum
= 0;
5000 QLIST_FOREACH(child
, &bs
->children
, next
) {
5001 if (child
->role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
|
5002 BDRV_CHILD_FILTERED
))
5004 child_size
= bdrv_get_allocated_file_size(child
->bs
);
5005 if (child_size
< 0) {
5016 * Length of a allocated file in bytes. Sparse files are counted by actual
5017 * allocated space. Return < 0 if error or unknown.
5019 int64_t bdrv_get_allocated_file_size(BlockDriverState
*bs
)
5021 BlockDriver
*drv
= bs
->drv
;
5025 if (drv
->bdrv_get_allocated_file_size
) {
5026 return drv
->bdrv_get_allocated_file_size(bs
);
5029 if (drv
->bdrv_file_open
) {
5031 * Protocol drivers default to -ENOTSUP (most of their data is
5032 * not stored in any of their children (if they even have any),
5033 * so there is no generic way to figure it out).
5036 } else if (drv
->is_filter
) {
5037 /* Filter drivers default to the size of their filtered child */
5038 return bdrv_get_allocated_file_size(bdrv_filter_bs(bs
));
5040 /* Other drivers default to summing their children's sizes */
5041 return bdrv_sum_allocated_file_size(bs
);
5047 * @drv: Format driver
5048 * @opts: Creation options for new image
5049 * @in_bs: Existing image containing data for new image (may be NULL)
5050 * @errp: Error object
5051 * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo())
5054 * Calculate file size required to create a new image.
5056 * If @in_bs is given then space for allocated clusters and zero clusters
5057 * from that image are included in the calculation. If @opts contains a
5058 * backing file that is shared by @in_bs then backing clusters may be omitted
5059 * from the calculation.
5061 * If @in_bs is NULL then the calculation includes no allocated clusters
5062 * unless a preallocation option is given in @opts.
5064 * Note that @in_bs may use a different BlockDriver from @drv.
5066 * If an error occurs the @errp pointer is set.
5068 BlockMeasureInfo
*bdrv_measure(BlockDriver
*drv
, QemuOpts
*opts
,
5069 BlockDriverState
*in_bs
, Error
**errp
)
5071 if (!drv
->bdrv_measure
) {
5072 error_setg(errp
, "Block driver '%s' does not support size measurement",
5077 return drv
->bdrv_measure(opts
, in_bs
, errp
);
5081 * Return number of sectors on success, -errno on error.
5083 int64_t bdrv_nb_sectors(BlockDriverState
*bs
)
5085 BlockDriver
*drv
= bs
->drv
;
5090 if (drv
->has_variable_length
) {
5091 int ret
= refresh_total_sectors(bs
, bs
->total_sectors
);
5096 return bs
->total_sectors
;
5100 * Return length in bytes on success, -errno on error.
5101 * The length is always a multiple of BDRV_SECTOR_SIZE.
5103 int64_t bdrv_getlength(BlockDriverState
*bs
)
5105 int64_t ret
= bdrv_nb_sectors(bs
);
5110 if (ret
> INT64_MAX
/ BDRV_SECTOR_SIZE
) {
5113 return ret
* BDRV_SECTOR_SIZE
;
5116 /* return 0 as number of sectors if no device present or error */
5117 void bdrv_get_geometry(BlockDriverState
*bs
, uint64_t *nb_sectors_ptr
)
5119 int64_t nb_sectors
= bdrv_nb_sectors(bs
);
5121 *nb_sectors_ptr
= nb_sectors
< 0 ? 0 : nb_sectors
;
5124 bool bdrv_is_sg(BlockDriverState
*bs
)
5130 * Return whether the given node supports compressed writes.
5132 bool bdrv_supports_compressed_writes(BlockDriverState
*bs
)
5134 BlockDriverState
*filtered
;
5136 if (!bs
->drv
|| !block_driver_can_compress(bs
->drv
)) {
5140 filtered
= bdrv_filter_bs(bs
);
5143 * Filters can only forward compressed writes, so we have to
5146 return bdrv_supports_compressed_writes(filtered
);
5152 const char *bdrv_get_format_name(BlockDriverState
*bs
)
5154 return bs
->drv
? bs
->drv
->format_name
: NULL
;
5157 static int qsort_strcmp(const void *a
, const void *b
)
5159 return strcmp(*(char *const *)a
, *(char *const *)b
);
5162 void bdrv_iterate_format(void (*it
)(void *opaque
, const char *name
),
5163 void *opaque
, bool read_only
)
5168 const char **formats
= NULL
;
5170 QLIST_FOREACH(drv
, &bdrv_drivers
, list
) {
5171 if (drv
->format_name
) {
5175 if (use_bdrv_whitelist
&& !bdrv_is_whitelisted(drv
, read_only
)) {
5179 while (formats
&& i
&& !found
) {
5180 found
= !strcmp(formats
[--i
], drv
->format_name
);
5184 formats
= g_renew(const char *, formats
, count
+ 1);
5185 formats
[count
++] = drv
->format_name
;
5190 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); i
++) {
5191 const char *format_name
= block_driver_modules
[i
].format_name
;
5197 if (use_bdrv_whitelist
&&
5198 !bdrv_format_is_whitelisted(format_name
, read_only
)) {
5202 while (formats
&& j
&& !found
) {
5203 found
= !strcmp(formats
[--j
], format_name
);
5207 formats
= g_renew(const char *, formats
, count
+ 1);
5208 formats
[count
++] = format_name
;
5213 qsort(formats
, count
, sizeof(formats
[0]), qsort_strcmp
);
5215 for (i
= 0; i
< count
; i
++) {
5216 it(opaque
, formats
[i
]);
5222 /* This function is to find a node in the bs graph */
5223 BlockDriverState
*bdrv_find_node(const char *node_name
)
5225 BlockDriverState
*bs
;
5229 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
5230 if (!strcmp(node_name
, bs
->node_name
)) {
5237 /* Put this QMP function here so it can access the static graph_bdrv_states. */
5238 BlockDeviceInfoList
*bdrv_named_nodes_list(bool flat
,
5241 BlockDeviceInfoList
*list
;
5242 BlockDriverState
*bs
;
5245 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
5246 BlockDeviceInfo
*info
= bdrv_block_device_info(NULL
, bs
, flat
, errp
);
5248 qapi_free_BlockDeviceInfoList(list
);
5251 QAPI_LIST_PREPEND(list
, info
);
5257 typedef struct XDbgBlockGraphConstructor
{
5258 XDbgBlockGraph
*graph
;
5259 GHashTable
*graph_nodes
;
5260 } XDbgBlockGraphConstructor
;
5262 static XDbgBlockGraphConstructor
*xdbg_graph_new(void)
5264 XDbgBlockGraphConstructor
*gr
= g_new(XDbgBlockGraphConstructor
, 1);
5266 gr
->graph
= g_new0(XDbgBlockGraph
, 1);
5267 gr
->graph_nodes
= g_hash_table_new(NULL
, NULL
);
5272 static XDbgBlockGraph
*xdbg_graph_finalize(XDbgBlockGraphConstructor
*gr
)
5274 XDbgBlockGraph
*graph
= gr
->graph
;
5276 g_hash_table_destroy(gr
->graph_nodes
);
5282 static uintptr_t xdbg_graph_node_num(XDbgBlockGraphConstructor
*gr
, void *node
)
5284 uintptr_t ret
= (uintptr_t)g_hash_table_lookup(gr
->graph_nodes
, node
);
5291 * Start counting from 1, not 0, because 0 interferes with not-found (NULL)
5292 * answer of g_hash_table_lookup.
5294 ret
= g_hash_table_size(gr
->graph_nodes
) + 1;
5295 g_hash_table_insert(gr
->graph_nodes
, node
, (void *)ret
);
5300 static void xdbg_graph_add_node(XDbgBlockGraphConstructor
*gr
, void *node
,
5301 XDbgBlockGraphNodeType type
, const char *name
)
5303 XDbgBlockGraphNode
*n
;
5305 n
= g_new0(XDbgBlockGraphNode
, 1);
5307 n
->id
= xdbg_graph_node_num(gr
, node
);
5309 n
->name
= g_strdup(name
);
5311 QAPI_LIST_PREPEND(gr
->graph
->nodes
, n
);
5314 static void xdbg_graph_add_edge(XDbgBlockGraphConstructor
*gr
, void *parent
,
5315 const BdrvChild
*child
)
5317 BlockPermission qapi_perm
;
5318 XDbgBlockGraphEdge
*edge
;
5320 edge
= g_new0(XDbgBlockGraphEdge
, 1);
5322 edge
->parent
= xdbg_graph_node_num(gr
, parent
);
5323 edge
->child
= xdbg_graph_node_num(gr
, child
->bs
);
5324 edge
->name
= g_strdup(child
->name
);
5326 for (qapi_perm
= 0; qapi_perm
< BLOCK_PERMISSION__MAX
; qapi_perm
++) {
5327 uint64_t flag
= bdrv_qapi_perm_to_blk_perm(qapi_perm
);
5329 if (flag
& child
->perm
) {
5330 QAPI_LIST_PREPEND(edge
->perm
, qapi_perm
);
5332 if (flag
& child
->shared_perm
) {
5333 QAPI_LIST_PREPEND(edge
->shared_perm
, qapi_perm
);
5337 QAPI_LIST_PREPEND(gr
->graph
->edges
, edge
);
5341 XDbgBlockGraph
*bdrv_get_xdbg_block_graph(Error
**errp
)
5345 BlockDriverState
*bs
;
5347 XDbgBlockGraphConstructor
*gr
= xdbg_graph_new();
5349 for (blk
= blk_all_next(NULL
); blk
; blk
= blk_all_next(blk
)) {
5350 char *allocated_name
= NULL
;
5351 const char *name
= blk_name(blk
);
5354 name
= allocated_name
= blk_get_attached_dev_id(blk
);
5356 xdbg_graph_add_node(gr
, blk
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND
,
5358 g_free(allocated_name
);
5359 if (blk_root(blk
)) {
5360 xdbg_graph_add_edge(gr
, blk
, blk_root(blk
));
5364 for (job
= block_job_next(NULL
); job
; job
= block_job_next(job
)) {
5367 xdbg_graph_add_node(gr
, job
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB
,
5369 for (el
= job
->nodes
; el
; el
= el
->next
) {
5370 xdbg_graph_add_edge(gr
, job
, (BdrvChild
*)el
->data
);
5374 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
5375 xdbg_graph_add_node(gr
, bs
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_DRIVER
,
5377 QLIST_FOREACH(child
, &bs
->children
, next
) {
5378 xdbg_graph_add_edge(gr
, bs
, child
);
5382 return xdbg_graph_finalize(gr
);
5385 BlockDriverState
*bdrv_lookup_bs(const char *device
,
5386 const char *node_name
,
5390 BlockDriverState
*bs
;
5393 blk
= blk_by_name(device
);
5398 error_setg(errp
, "Device '%s' has no medium", device
);
5406 bs
= bdrv_find_node(node_name
);
5413 error_setg(errp
, "Cannot find device=%s nor node_name=%s",
5414 device
? device
: "",
5415 node_name
? node_name
: "");
5419 /* If 'base' is in the same chain as 'top', return true. Otherwise,
5420 * return false. If either argument is NULL, return false. */
5421 bool bdrv_chain_contains(BlockDriverState
*top
, BlockDriverState
*base
)
5423 while (top
&& top
!= base
) {
5424 top
= bdrv_filter_or_cow_bs(top
);
5430 BlockDriverState
*bdrv_next_node(BlockDriverState
*bs
)
5433 return QTAILQ_FIRST(&graph_bdrv_states
);
5435 return QTAILQ_NEXT(bs
, node_list
);
5438 BlockDriverState
*bdrv_next_all_states(BlockDriverState
*bs
)
5441 return QTAILQ_FIRST(&all_bdrv_states
);
5443 return QTAILQ_NEXT(bs
, bs_list
);
5446 const char *bdrv_get_node_name(const BlockDriverState
*bs
)
5448 return bs
->node_name
;
5451 const char *bdrv_get_parent_name(const BlockDriverState
*bs
)
5456 /* If multiple parents have a name, just pick the first one. */
5457 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
5458 if (c
->klass
->get_name
) {
5459 name
= c
->klass
->get_name(c
);
5460 if (name
&& *name
) {
5469 /* TODO check what callers really want: bs->node_name or blk_name() */
5470 const char *bdrv_get_device_name(const BlockDriverState
*bs
)
5472 return bdrv_get_parent_name(bs
) ?: "";
5475 /* This can be used to identify nodes that might not have a device
5476 * name associated. Since node and device names live in the same
5477 * namespace, the result is unambiguous. The exception is if both are
5478 * absent, then this returns an empty (non-null) string. */
5479 const char *bdrv_get_device_or_node_name(const BlockDriverState
*bs
)
5481 return bdrv_get_parent_name(bs
) ?: bs
->node_name
;
5484 int bdrv_get_flags(BlockDriverState
*bs
)
5486 return bs
->open_flags
;
5489 int bdrv_has_zero_init_1(BlockDriverState
*bs
)
5494 int bdrv_has_zero_init(BlockDriverState
*bs
)
5496 BlockDriverState
*filtered
;
5502 /* If BS is a copy on write image, it is initialized to
5503 the contents of the base image, which may not be zeroes. */
5504 if (bdrv_cow_child(bs
)) {
5507 if (bs
->drv
->bdrv_has_zero_init
) {
5508 return bs
->drv
->bdrv_has_zero_init(bs
);
5511 filtered
= bdrv_filter_bs(bs
);
5513 return bdrv_has_zero_init(filtered
);
5520 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState
*bs
)
5522 if (!(bs
->open_flags
& BDRV_O_UNMAP
)) {
5526 return bs
->supported_zero_flags
& BDRV_REQ_MAY_UNMAP
;
5529 void bdrv_get_backing_filename(BlockDriverState
*bs
,
5530 char *filename
, int filename_size
)
5532 pstrcpy(filename
, filename_size
, bs
->backing_file
);
5535 int bdrv_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
5538 BlockDriver
*drv
= bs
->drv
;
5539 /* if bs->drv == NULL, bs is closed, so there's nothing to do here */
5543 if (!drv
->bdrv_get_info
) {
5544 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
5546 return bdrv_get_info(filtered
, bdi
);
5550 memset(bdi
, 0, sizeof(*bdi
));
5551 ret
= drv
->bdrv_get_info(bs
, bdi
);
5556 if (bdi
->cluster_size
> BDRV_MAX_ALIGNMENT
) {
5563 ImageInfoSpecific
*bdrv_get_specific_info(BlockDriverState
*bs
,
5566 BlockDriver
*drv
= bs
->drv
;
5567 if (drv
&& drv
->bdrv_get_specific_info
) {
5568 return drv
->bdrv_get_specific_info(bs
, errp
);
5573 BlockStatsSpecific
*bdrv_get_specific_stats(BlockDriverState
*bs
)
5575 BlockDriver
*drv
= bs
->drv
;
5576 if (!drv
|| !drv
->bdrv_get_specific_stats
) {
5579 return drv
->bdrv_get_specific_stats(bs
);
5582 void bdrv_debug_event(BlockDriverState
*bs
, BlkdebugEvent event
)
5584 if (!bs
|| !bs
->drv
|| !bs
->drv
->bdrv_debug_event
) {
5588 bs
->drv
->bdrv_debug_event(bs
, event
);
5591 static BlockDriverState
*bdrv_find_debug_node(BlockDriverState
*bs
)
5593 while (bs
&& bs
->drv
&& !bs
->drv
->bdrv_debug_breakpoint
) {
5594 bs
= bdrv_primary_bs(bs
);
5597 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_breakpoint
) {
5598 assert(bs
->drv
->bdrv_debug_remove_breakpoint
);
5605 int bdrv_debug_breakpoint(BlockDriverState
*bs
, const char *event
,
5608 bs
= bdrv_find_debug_node(bs
);
5610 return bs
->drv
->bdrv_debug_breakpoint(bs
, event
, tag
);
5616 int bdrv_debug_remove_breakpoint(BlockDriverState
*bs
, const char *tag
)
5618 bs
= bdrv_find_debug_node(bs
);
5620 return bs
->drv
->bdrv_debug_remove_breakpoint(bs
, tag
);
5626 int bdrv_debug_resume(BlockDriverState
*bs
, const char *tag
)
5628 while (bs
&& (!bs
->drv
|| !bs
->drv
->bdrv_debug_resume
)) {
5629 bs
= bdrv_primary_bs(bs
);
5632 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_resume
) {
5633 return bs
->drv
->bdrv_debug_resume(bs
, tag
);
5639 bool bdrv_debug_is_suspended(BlockDriverState
*bs
, const char *tag
)
5641 while (bs
&& bs
->drv
&& !bs
->drv
->bdrv_debug_is_suspended
) {
5642 bs
= bdrv_primary_bs(bs
);
5645 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_is_suspended
) {
5646 return bs
->drv
->bdrv_debug_is_suspended(bs
, tag
);
5652 /* backing_file can either be relative, or absolute, or a protocol. If it is
5653 * relative, it must be relative to the chain. So, passing in bs->filename
5654 * from a BDS as backing_file should not be done, as that may be relative to
5655 * the CWD rather than the chain. */
5656 BlockDriverState
*bdrv_find_backing_image(BlockDriverState
*bs
,
5657 const char *backing_file
)
5659 char *filename_full
= NULL
;
5660 char *backing_file_full
= NULL
;
5661 char *filename_tmp
= NULL
;
5662 int is_protocol
= 0;
5663 bool filenames_refreshed
= false;
5664 BlockDriverState
*curr_bs
= NULL
;
5665 BlockDriverState
*retval
= NULL
;
5666 BlockDriverState
*bs_below
;
5668 if (!bs
|| !bs
->drv
|| !backing_file
) {
5672 filename_full
= g_malloc(PATH_MAX
);
5673 backing_file_full
= g_malloc(PATH_MAX
);
5675 is_protocol
= path_has_protocol(backing_file
);
5678 * Being largely a legacy function, skip any filters here
5679 * (because filters do not have normal filenames, so they cannot
5680 * match anyway; and allowing json:{} filenames is a bit out of
5683 for (curr_bs
= bdrv_skip_filters(bs
);
5684 bdrv_cow_child(curr_bs
) != NULL
;
5687 bs_below
= bdrv_backing_chain_next(curr_bs
);
5689 if (bdrv_backing_overridden(curr_bs
)) {
5691 * If the backing file was overridden, we can only compare
5692 * directly against the backing node's filename.
5695 if (!filenames_refreshed
) {
5697 * This will automatically refresh all of the
5698 * filenames in the rest of the backing chain, so we
5699 * only need to do this once.
5701 bdrv_refresh_filename(bs_below
);
5702 filenames_refreshed
= true;
5705 if (strcmp(backing_file
, bs_below
->filename
) == 0) {
5709 } else if (is_protocol
|| path_has_protocol(curr_bs
->backing_file
)) {
5711 * If either of the filename paths is actually a protocol, then
5712 * compare unmodified paths; otherwise make paths relative.
5714 char *backing_file_full_ret
;
5716 if (strcmp(backing_file
, curr_bs
->backing_file
) == 0) {
5720 /* Also check against the full backing filename for the image */
5721 backing_file_full_ret
= bdrv_get_full_backing_filename(curr_bs
,
5723 if (backing_file_full_ret
) {
5724 bool equal
= strcmp(backing_file
, backing_file_full_ret
) == 0;
5725 g_free(backing_file_full_ret
);
5732 /* If not an absolute filename path, make it relative to the current
5733 * image's filename path */
5734 filename_tmp
= bdrv_make_absolute_filename(curr_bs
, backing_file
,
5736 /* We are going to compare canonicalized absolute pathnames */
5737 if (!filename_tmp
|| !realpath(filename_tmp
, filename_full
)) {
5738 g_free(filename_tmp
);
5741 g_free(filename_tmp
);
5743 /* We need to make sure the backing filename we are comparing against
5744 * is relative to the current image filename (or absolute) */
5745 filename_tmp
= bdrv_get_full_backing_filename(curr_bs
, NULL
);
5746 if (!filename_tmp
|| !realpath(filename_tmp
, backing_file_full
)) {
5747 g_free(filename_tmp
);
5750 g_free(filename_tmp
);
5752 if (strcmp(backing_file_full
, filename_full
) == 0) {
5759 g_free(filename_full
);
5760 g_free(backing_file_full
);
5764 void bdrv_init(void)
5766 module_call_init(MODULE_INIT_BLOCK
);
5769 void bdrv_init_with_whitelist(void)
5771 use_bdrv_whitelist
= 1;
5775 int coroutine_fn
bdrv_co_invalidate_cache(BlockDriverState
*bs
, Error
**errp
)
5777 BdrvChild
*child
, *parent
;
5778 Error
*local_err
= NULL
;
5780 BdrvDirtyBitmap
*bm
;
5786 QLIST_FOREACH(child
, &bs
->children
, next
) {
5787 bdrv_co_invalidate_cache(child
->bs
, &local_err
);
5789 error_propagate(errp
, local_err
);
5795 * Update permissions, they may differ for inactive nodes.
5797 * Note that the required permissions of inactive images are always a
5798 * subset of the permissions required after activating the image. This
5799 * allows us to just get the permissions upfront without restricting
5800 * drv->bdrv_invalidate_cache().
5802 * It also means that in error cases, we don't have to try and revert to
5803 * the old permissions (which is an operation that could fail, too). We can
5804 * just keep the extended permissions for the next time that an activation
5805 * of the image is tried.
5807 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
5808 bs
->open_flags
&= ~BDRV_O_INACTIVE
;
5809 ret
= bdrv_refresh_perms(bs
, errp
);
5811 bs
->open_flags
|= BDRV_O_INACTIVE
;
5815 if (bs
->drv
->bdrv_co_invalidate_cache
) {
5816 bs
->drv
->bdrv_co_invalidate_cache(bs
, &local_err
);
5818 bs
->open_flags
|= BDRV_O_INACTIVE
;
5819 error_propagate(errp
, local_err
);
5824 FOR_EACH_DIRTY_BITMAP(bs
, bm
) {
5825 bdrv_dirty_bitmap_skip_store(bm
, false);
5828 ret
= refresh_total_sectors(bs
, bs
->total_sectors
);
5830 bs
->open_flags
|= BDRV_O_INACTIVE
;
5831 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
5836 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
5837 if (parent
->klass
->activate
) {
5838 parent
->klass
->activate(parent
, &local_err
);
5840 bs
->open_flags
|= BDRV_O_INACTIVE
;
5841 error_propagate(errp
, local_err
);
5850 void bdrv_invalidate_cache_all(Error
**errp
)
5852 BlockDriverState
*bs
;
5853 BdrvNextIterator it
;
5855 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
5856 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
5859 aio_context_acquire(aio_context
);
5860 ret
= bdrv_invalidate_cache(bs
, errp
);
5861 aio_context_release(aio_context
);
5863 bdrv_next_cleanup(&it
);
5869 static bool bdrv_has_bds_parent(BlockDriverState
*bs
, bool only_active
)
5873 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
5874 if (parent
->klass
->parent_is_bds
) {
5875 BlockDriverState
*parent_bs
= parent
->opaque
;
5876 if (!only_active
|| !(parent_bs
->open_flags
& BDRV_O_INACTIVE
)) {
5885 static int bdrv_inactivate_recurse(BlockDriverState
*bs
)
5887 BdrvChild
*child
, *parent
;
5894 /* Make sure that we don't inactivate a child before its parent.
5895 * It will be covered by recursion from the yet active parent. */
5896 if (bdrv_has_bds_parent(bs
, true)) {
5900 assert(!(bs
->open_flags
& BDRV_O_INACTIVE
));
5902 /* Inactivate this node */
5903 if (bs
->drv
->bdrv_inactivate
) {
5904 ret
= bs
->drv
->bdrv_inactivate(bs
);
5910 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
5911 if (parent
->klass
->inactivate
) {
5912 ret
= parent
->klass
->inactivate(parent
);
5919 bs
->open_flags
|= BDRV_O_INACTIVE
;
5922 * Update permissions, they may differ for inactive nodes.
5923 * We only tried to loosen restrictions, so errors are not fatal, ignore
5926 bdrv_refresh_perms(bs
, NULL
);
5928 /* Recursively inactivate children */
5929 QLIST_FOREACH(child
, &bs
->children
, next
) {
5930 ret
= bdrv_inactivate_recurse(child
->bs
);
5939 int bdrv_inactivate_all(void)
5941 BlockDriverState
*bs
= NULL
;
5942 BdrvNextIterator it
;
5944 GSList
*aio_ctxs
= NULL
, *ctx
;
5946 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
5947 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
5949 if (!g_slist_find(aio_ctxs
, aio_context
)) {
5950 aio_ctxs
= g_slist_prepend(aio_ctxs
, aio_context
);
5951 aio_context_acquire(aio_context
);
5955 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
5956 /* Nodes with BDS parents are covered by recursion from the last
5957 * parent that gets inactivated. Don't inactivate them a second
5958 * time if that has already happened. */
5959 if (bdrv_has_bds_parent(bs
, false)) {
5962 ret
= bdrv_inactivate_recurse(bs
);
5964 bdrv_next_cleanup(&it
);
5970 for (ctx
= aio_ctxs
; ctx
!= NULL
; ctx
= ctx
->next
) {
5971 AioContext
*aio_context
= ctx
->data
;
5972 aio_context_release(aio_context
);
5974 g_slist_free(aio_ctxs
);
5979 /**************************************************************/
5980 /* removable device support */
5983 * Return TRUE if the media is present
5985 bool bdrv_is_inserted(BlockDriverState
*bs
)
5987 BlockDriver
*drv
= bs
->drv
;
5993 if (drv
->bdrv_is_inserted
) {
5994 return drv
->bdrv_is_inserted(bs
);
5996 QLIST_FOREACH(child
, &bs
->children
, next
) {
5997 if (!bdrv_is_inserted(child
->bs
)) {
6005 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
6007 void bdrv_eject(BlockDriverState
*bs
, bool eject_flag
)
6009 BlockDriver
*drv
= bs
->drv
;
6011 if (drv
&& drv
->bdrv_eject
) {
6012 drv
->bdrv_eject(bs
, eject_flag
);
6017 * Lock or unlock the media (if it is locked, the user won't be able
6018 * to eject it manually).
6020 void bdrv_lock_medium(BlockDriverState
*bs
, bool locked
)
6022 BlockDriver
*drv
= bs
->drv
;
6024 trace_bdrv_lock_medium(bs
, locked
);
6026 if (drv
&& drv
->bdrv_lock_medium
) {
6027 drv
->bdrv_lock_medium(bs
, locked
);
6031 /* Get a reference to bs */
6032 void bdrv_ref(BlockDriverState
*bs
)
6037 /* Release a previously grabbed reference to bs.
6038 * If after releasing, reference count is zero, the BlockDriverState is
6040 void bdrv_unref(BlockDriverState
*bs
)
6045 assert(bs
->refcnt
> 0);
6046 if (--bs
->refcnt
== 0) {
6051 struct BdrvOpBlocker
{
6053 QLIST_ENTRY(BdrvOpBlocker
) list
;
6056 bool bdrv_op_is_blocked(BlockDriverState
*bs
, BlockOpType op
, Error
**errp
)
6058 BdrvOpBlocker
*blocker
;
6059 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
6060 if (!QLIST_EMPTY(&bs
->op_blockers
[op
])) {
6061 blocker
= QLIST_FIRST(&bs
->op_blockers
[op
]);
6062 error_propagate_prepend(errp
, error_copy(blocker
->reason
),
6063 "Node '%s' is busy: ",
6064 bdrv_get_device_or_node_name(bs
));
6070 void bdrv_op_block(BlockDriverState
*bs
, BlockOpType op
, Error
*reason
)
6072 BdrvOpBlocker
*blocker
;
6073 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
6075 blocker
= g_new0(BdrvOpBlocker
, 1);
6076 blocker
->reason
= reason
;
6077 QLIST_INSERT_HEAD(&bs
->op_blockers
[op
], blocker
, list
);
6080 void bdrv_op_unblock(BlockDriverState
*bs
, BlockOpType op
, Error
*reason
)
6082 BdrvOpBlocker
*blocker
, *next
;
6083 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
6084 QLIST_FOREACH_SAFE(blocker
, &bs
->op_blockers
[op
], list
, next
) {
6085 if (blocker
->reason
== reason
) {
6086 QLIST_REMOVE(blocker
, list
);
6092 void bdrv_op_block_all(BlockDriverState
*bs
, Error
*reason
)
6095 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
6096 bdrv_op_block(bs
, i
, reason
);
6100 void bdrv_op_unblock_all(BlockDriverState
*bs
, Error
*reason
)
6103 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
6104 bdrv_op_unblock(bs
, i
, reason
);
6108 bool bdrv_op_blocker_is_empty(BlockDriverState
*bs
)
6112 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
6113 if (!QLIST_EMPTY(&bs
->op_blockers
[i
])) {
6120 void bdrv_img_create(const char *filename
, const char *fmt
,
6121 const char *base_filename
, const char *base_fmt
,
6122 char *options
, uint64_t img_size
, int flags
, bool quiet
,
6125 QemuOptsList
*create_opts
= NULL
;
6126 QemuOpts
*opts
= NULL
;
6127 const char *backing_fmt
, *backing_file
;
6129 BlockDriver
*drv
, *proto_drv
;
6130 Error
*local_err
= NULL
;
6133 /* Find driver and parse its options */
6134 drv
= bdrv_find_format(fmt
);
6136 error_setg(errp
, "Unknown file format '%s'", fmt
);
6140 proto_drv
= bdrv_find_protocol(filename
, true, errp
);
6145 if (!drv
->create_opts
) {
6146 error_setg(errp
, "Format driver '%s' does not support image creation",
6151 if (!proto_drv
->create_opts
) {
6152 error_setg(errp
, "Protocol driver '%s' does not support image creation",
6153 proto_drv
->format_name
);
6157 /* Create parameter list */
6158 create_opts
= qemu_opts_append(create_opts
, drv
->create_opts
);
6159 create_opts
= qemu_opts_append(create_opts
, proto_drv
->create_opts
);
6161 opts
= qemu_opts_create(create_opts
, NULL
, 0, &error_abort
);
6163 /* Parse -o options */
6165 if (!qemu_opts_do_parse(opts
, options
, NULL
, errp
)) {
6170 if (!qemu_opt_get(opts
, BLOCK_OPT_SIZE
)) {
6171 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, img_size
, &error_abort
);
6172 } else if (img_size
!= UINT64_C(-1)) {
6173 error_setg(errp
, "The image size must be specified only once");
6177 if (base_filename
) {
6178 if (!qemu_opt_set(opts
, BLOCK_OPT_BACKING_FILE
, base_filename
,
6180 error_setg(errp
, "Backing file not supported for file format '%s'",
6187 if (!qemu_opt_set(opts
, BLOCK_OPT_BACKING_FMT
, base_fmt
, NULL
)) {
6188 error_setg(errp
, "Backing file format not supported for file "
6189 "format '%s'", fmt
);
6194 backing_file
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FILE
);
6196 if (!strcmp(filename
, backing_file
)) {
6197 error_setg(errp
, "Error: Trying to create an image with the "
6198 "same filename as the backing file");
6201 if (backing_file
[0] == '\0') {
6202 error_setg(errp
, "Expected backing file name, got empty string");
6207 backing_fmt
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FMT
);
6209 /* The size for the image must always be specified, unless we have a backing
6210 * file and we have not been forbidden from opening it. */
6211 size
= qemu_opt_get_size(opts
, BLOCK_OPT_SIZE
, img_size
);
6212 if (backing_file
&& !(flags
& BDRV_O_NO_BACKING
)) {
6213 BlockDriverState
*bs
;
6216 QDict
*backing_options
= NULL
;
6219 bdrv_get_full_backing_filename_from_filename(filename
, backing_file
,
6224 assert(full_backing
);
6226 /* backing files always opened read-only */
6228 back_flags
&= ~(BDRV_O_RDWR
| BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
);
6230 backing_options
= qdict_new();
6232 qdict_put_str(backing_options
, "driver", backing_fmt
);
6234 qdict_put_bool(backing_options
, BDRV_OPT_FORCE_SHARE
, true);
6236 bs
= bdrv_open(full_backing
, NULL
, backing_options
, back_flags
,
6238 g_free(full_backing
);
6240 error_append_hint(&local_err
, "Could not open backing image.\n");
6244 warn_report("Deprecated use of backing file without explicit "
6245 "backing format (detected format of %s)",
6246 bs
->drv
->format_name
);
6247 if (bs
->drv
!= &bdrv_raw
) {
6249 * A probe of raw deserves the most attention:
6250 * leaving the backing format out of the image
6251 * will ensure bs->probed is set (ensuring we
6252 * don't accidentally commit into the backing
6253 * file), and allow more spots to warn the users
6254 * to fix their toolchain when opening this image
6255 * later. For other images, we can safely record
6256 * the format that we probed.
6258 backing_fmt
= bs
->drv
->format_name
;
6259 qemu_opt_set(opts
, BLOCK_OPT_BACKING_FMT
, backing_fmt
,
6264 /* Opened BS, have no size */
6265 size
= bdrv_getlength(bs
);
6267 error_setg_errno(errp
, -size
, "Could not get size of '%s'",
6272 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, size
, &error_abort
);
6276 /* (backing_file && !(flags & BDRV_O_NO_BACKING)) */
6277 } else if (backing_file
&& !backing_fmt
) {
6278 warn_report("Deprecated use of unopened backing file without "
6279 "explicit backing format, use of this image requires "
6280 "potentially unsafe format probing");
6284 error_setg(errp
, "Image creation needs a size parameter");
6289 printf("Formatting '%s', fmt=%s ", filename
, fmt
);
6290 qemu_opts_print(opts
, " ");
6295 ret
= bdrv_create(drv
, filename
, opts
, &local_err
);
6297 if (ret
== -EFBIG
) {
6298 /* This is generally a better message than whatever the driver would
6299 * deliver (especially because of the cluster_size_hint), since that
6300 * is most probably not much different from "image too large". */
6301 const char *cluster_size_hint
= "";
6302 if (qemu_opt_get_size(opts
, BLOCK_OPT_CLUSTER_SIZE
, 0)) {
6303 cluster_size_hint
= " (try using a larger cluster size)";
6305 error_setg(errp
, "The image size is too large for file format '%s'"
6306 "%s", fmt
, cluster_size_hint
);
6307 error_free(local_err
);
6312 qemu_opts_del(opts
);
6313 qemu_opts_free(create_opts
);
6314 error_propagate(errp
, local_err
);
6317 AioContext
*bdrv_get_aio_context(BlockDriverState
*bs
)
6319 return bs
? bs
->aio_context
: qemu_get_aio_context();
6322 AioContext
*coroutine_fn
bdrv_co_enter(BlockDriverState
*bs
)
6324 Coroutine
*self
= qemu_coroutine_self();
6325 AioContext
*old_ctx
= qemu_coroutine_get_aio_context(self
);
6326 AioContext
*new_ctx
;
6329 * Increase bs->in_flight to ensure that this operation is completed before
6330 * moving the node to a different AioContext. Read new_ctx only afterwards.
6332 bdrv_inc_in_flight(bs
);
6334 new_ctx
= bdrv_get_aio_context(bs
);
6335 aio_co_reschedule_self(new_ctx
);
6339 void coroutine_fn
bdrv_co_leave(BlockDriverState
*bs
, AioContext
*old_ctx
)
6341 aio_co_reschedule_self(old_ctx
);
6342 bdrv_dec_in_flight(bs
);
6345 void coroutine_fn
bdrv_co_lock(BlockDriverState
*bs
)
6347 AioContext
*ctx
= bdrv_get_aio_context(bs
);
6349 /* In the main thread, bs->aio_context won't change concurrently */
6350 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
6353 * We're in coroutine context, so we already hold the lock of the main
6354 * loop AioContext. Don't lock it twice to avoid deadlocks.
6356 assert(qemu_in_coroutine());
6357 if (ctx
!= qemu_get_aio_context()) {
6358 aio_context_acquire(ctx
);
6362 void coroutine_fn
bdrv_co_unlock(BlockDriverState
*bs
)
6364 AioContext
*ctx
= bdrv_get_aio_context(bs
);
6366 assert(qemu_in_coroutine());
6367 if (ctx
!= qemu_get_aio_context()) {
6368 aio_context_release(ctx
);
6372 void bdrv_coroutine_enter(BlockDriverState
*bs
, Coroutine
*co
)
6374 aio_co_enter(bdrv_get_aio_context(bs
), co
);
6377 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier
*ban
)
6379 QLIST_REMOVE(ban
, list
);
6383 static void bdrv_detach_aio_context(BlockDriverState
*bs
)
6385 BdrvAioNotifier
*baf
, *baf_tmp
;
6387 assert(!bs
->walking_aio_notifiers
);
6388 bs
->walking_aio_notifiers
= true;
6389 QLIST_FOREACH_SAFE(baf
, &bs
->aio_notifiers
, list
, baf_tmp
) {
6391 bdrv_do_remove_aio_context_notifier(baf
);
6393 baf
->detach_aio_context(baf
->opaque
);
6396 /* Never mind iterating again to check for ->deleted. bdrv_close() will
6397 * remove remaining aio notifiers if we aren't called again.
6399 bs
->walking_aio_notifiers
= false;
6401 if (bs
->drv
&& bs
->drv
->bdrv_detach_aio_context
) {
6402 bs
->drv
->bdrv_detach_aio_context(bs
);
6405 if (bs
->quiesce_counter
) {
6406 aio_enable_external(bs
->aio_context
);
6408 bs
->aio_context
= NULL
;
6411 static void bdrv_attach_aio_context(BlockDriverState
*bs
,
6412 AioContext
*new_context
)
6414 BdrvAioNotifier
*ban
, *ban_tmp
;
6416 if (bs
->quiesce_counter
) {
6417 aio_disable_external(new_context
);
6420 bs
->aio_context
= new_context
;
6422 if (bs
->drv
&& bs
->drv
->bdrv_attach_aio_context
) {
6423 bs
->drv
->bdrv_attach_aio_context(bs
, new_context
);
6426 assert(!bs
->walking_aio_notifiers
);
6427 bs
->walking_aio_notifiers
= true;
6428 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_tmp
) {
6430 bdrv_do_remove_aio_context_notifier(ban
);
6432 ban
->attached_aio_context(new_context
, ban
->opaque
);
6435 bs
->walking_aio_notifiers
= false;
6439 * Changes the AioContext used for fd handlers, timers, and BHs by this
6440 * BlockDriverState and all its children and parents.
6442 * Must be called from the main AioContext.
6444 * The caller must own the AioContext lock for the old AioContext of bs, but it
6445 * must not own the AioContext lock for new_context (unless new_context is the
6446 * same as the current context of bs).
6448 * @ignore will accumulate all visited BdrvChild object. The caller is
6449 * responsible for freeing the list afterwards.
6451 void bdrv_set_aio_context_ignore(BlockDriverState
*bs
,
6452 AioContext
*new_context
, GSList
**ignore
)
6454 AioContext
*old_context
= bdrv_get_aio_context(bs
);
6455 GSList
*children_to_process
= NULL
;
6456 GSList
*parents_to_process
= NULL
;
6458 BdrvChild
*child
, *parent
;
6460 g_assert(qemu_get_current_aio_context() == qemu_get_aio_context());
6462 if (old_context
== new_context
) {
6466 bdrv_drained_begin(bs
);
6468 QLIST_FOREACH(child
, &bs
->children
, next
) {
6469 if (g_slist_find(*ignore
, child
)) {
6472 *ignore
= g_slist_prepend(*ignore
, child
);
6473 children_to_process
= g_slist_prepend(children_to_process
, child
);
6476 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6477 if (g_slist_find(*ignore
, parent
)) {
6480 *ignore
= g_slist_prepend(*ignore
, parent
);
6481 parents_to_process
= g_slist_prepend(parents_to_process
, parent
);
6484 for (entry
= children_to_process
;
6486 entry
= g_slist_next(entry
)) {
6487 child
= entry
->data
;
6488 bdrv_set_aio_context_ignore(child
->bs
, new_context
, ignore
);
6490 g_slist_free(children_to_process
);
6492 for (entry
= parents_to_process
;
6494 entry
= g_slist_next(entry
)) {
6495 parent
= entry
->data
;
6496 assert(parent
->klass
->set_aio_ctx
);
6497 parent
->klass
->set_aio_ctx(parent
, new_context
, ignore
);
6499 g_slist_free(parents_to_process
);
6501 bdrv_detach_aio_context(bs
);
6503 /* Acquire the new context, if necessary */
6504 if (qemu_get_aio_context() != new_context
) {
6505 aio_context_acquire(new_context
);
6508 bdrv_attach_aio_context(bs
, new_context
);
6511 * If this function was recursively called from
6512 * bdrv_set_aio_context_ignore(), there may be nodes in the
6513 * subtree that have not yet been moved to the new AioContext.
6514 * Release the old one so bdrv_drained_end() can poll them.
6516 if (qemu_get_aio_context() != old_context
) {
6517 aio_context_release(old_context
);
6520 bdrv_drained_end(bs
);
6522 if (qemu_get_aio_context() != old_context
) {
6523 aio_context_acquire(old_context
);
6525 if (qemu_get_aio_context() != new_context
) {
6526 aio_context_release(new_context
);
6530 static bool bdrv_parent_can_set_aio_context(BdrvChild
*c
, AioContext
*ctx
,
6531 GSList
**ignore
, Error
**errp
)
6533 if (g_slist_find(*ignore
, c
)) {
6536 *ignore
= g_slist_prepend(*ignore
, c
);
6539 * A BdrvChildClass that doesn't handle AioContext changes cannot
6540 * tolerate any AioContext changes
6542 if (!c
->klass
->can_set_aio_ctx
) {
6543 char *user
= bdrv_child_user_desc(c
);
6544 error_setg(errp
, "Changing iothreads is not supported by %s", user
);
6548 if (!c
->klass
->can_set_aio_ctx(c
, ctx
, ignore
, errp
)) {
6549 assert(!errp
|| *errp
);
6555 bool bdrv_child_can_set_aio_context(BdrvChild
*c
, AioContext
*ctx
,
6556 GSList
**ignore
, Error
**errp
)
6558 if (g_slist_find(*ignore
, c
)) {
6561 *ignore
= g_slist_prepend(*ignore
, c
);
6562 return bdrv_can_set_aio_context(c
->bs
, ctx
, ignore
, errp
);
6565 /* @ignore will accumulate all visited BdrvChild object. The caller is
6566 * responsible for freeing the list afterwards. */
6567 bool bdrv_can_set_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
6568 GSList
**ignore
, Error
**errp
)
6572 if (bdrv_get_aio_context(bs
) == ctx
) {
6576 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
6577 if (!bdrv_parent_can_set_aio_context(c
, ctx
, ignore
, errp
)) {
6581 QLIST_FOREACH(c
, &bs
->children
, next
) {
6582 if (!bdrv_child_can_set_aio_context(c
, ctx
, ignore
, errp
)) {
6590 int bdrv_child_try_set_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
6591 BdrvChild
*ignore_child
, Error
**errp
)
6596 ignore
= ignore_child
? g_slist_prepend(NULL
, ignore_child
) : NULL
;
6597 ret
= bdrv_can_set_aio_context(bs
, ctx
, &ignore
, errp
);
6598 g_slist_free(ignore
);
6604 ignore
= ignore_child
? g_slist_prepend(NULL
, ignore_child
) : NULL
;
6605 bdrv_set_aio_context_ignore(bs
, ctx
, &ignore
);
6606 g_slist_free(ignore
);
6611 int bdrv_try_set_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
6614 return bdrv_child_try_set_aio_context(bs
, ctx
, NULL
, errp
);
6617 void bdrv_add_aio_context_notifier(BlockDriverState
*bs
,
6618 void (*attached_aio_context
)(AioContext
*new_context
, void *opaque
),
6619 void (*detach_aio_context
)(void *opaque
), void *opaque
)
6621 BdrvAioNotifier
*ban
= g_new(BdrvAioNotifier
, 1);
6622 *ban
= (BdrvAioNotifier
){
6623 .attached_aio_context
= attached_aio_context
,
6624 .detach_aio_context
= detach_aio_context
,
6628 QLIST_INSERT_HEAD(&bs
->aio_notifiers
, ban
, list
);
6631 void bdrv_remove_aio_context_notifier(BlockDriverState
*bs
,
6632 void (*attached_aio_context
)(AioContext
*,
6634 void (*detach_aio_context
)(void *),
6637 BdrvAioNotifier
*ban
, *ban_next
;
6639 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_next
) {
6640 if (ban
->attached_aio_context
== attached_aio_context
&&
6641 ban
->detach_aio_context
== detach_aio_context
&&
6642 ban
->opaque
== opaque
&&
6643 ban
->deleted
== false)
6645 if (bs
->walking_aio_notifiers
) {
6646 ban
->deleted
= true;
6648 bdrv_do_remove_aio_context_notifier(ban
);
6657 int bdrv_amend_options(BlockDriverState
*bs
, QemuOpts
*opts
,
6658 BlockDriverAmendStatusCB
*status_cb
, void *cb_opaque
,
6663 error_setg(errp
, "Node is ejected");
6666 if (!bs
->drv
->bdrv_amend_options
) {
6667 error_setg(errp
, "Block driver '%s' does not support option amendment",
6668 bs
->drv
->format_name
);
6671 return bs
->drv
->bdrv_amend_options(bs
, opts
, status_cb
,
6672 cb_opaque
, force
, errp
);
6676 * This function checks whether the given @to_replace is allowed to be
6677 * replaced by a node that always shows the same data as @bs. This is
6678 * used for example to verify whether the mirror job can replace
6679 * @to_replace by the target mirrored from @bs.
6680 * To be replaceable, @bs and @to_replace may either be guaranteed to
6681 * always show the same data (because they are only connected through
6682 * filters), or some driver may allow replacing one of its children
6683 * because it can guarantee that this child's data is not visible at
6684 * all (for example, for dissenting quorum children that have no other
6687 bool bdrv_recurse_can_replace(BlockDriverState
*bs
,
6688 BlockDriverState
*to_replace
)
6690 BlockDriverState
*filtered
;
6692 if (!bs
|| !bs
->drv
) {
6696 if (bs
== to_replace
) {
6700 /* See what the driver can do */
6701 if (bs
->drv
->bdrv_recurse_can_replace
) {
6702 return bs
->drv
->bdrv_recurse_can_replace(bs
, to_replace
);
6705 /* For filters without an own implementation, we can recurse on our own */
6706 filtered
= bdrv_filter_bs(bs
);
6708 return bdrv_recurse_can_replace(filtered
, to_replace
);
6716 * Check whether the given @node_name can be replaced by a node that
6717 * has the same data as @parent_bs. If so, return @node_name's BDS;
6720 * @node_name must be a (recursive) *child of @parent_bs (or this
6721 * function will return NULL).
6723 * The result (whether the node can be replaced or not) is only valid
6724 * for as long as no graph or permission changes occur.
6726 BlockDriverState
*check_to_replace_node(BlockDriverState
*parent_bs
,
6727 const char *node_name
, Error
**errp
)
6729 BlockDriverState
*to_replace_bs
= bdrv_find_node(node_name
);
6730 AioContext
*aio_context
;
6732 if (!to_replace_bs
) {
6733 error_setg(errp
, "Node name '%s' not found", node_name
);
6737 aio_context
= bdrv_get_aio_context(to_replace_bs
);
6738 aio_context_acquire(aio_context
);
6740 if (bdrv_op_is_blocked(to_replace_bs
, BLOCK_OP_TYPE_REPLACE
, errp
)) {
6741 to_replace_bs
= NULL
;
6745 /* We don't want arbitrary node of the BDS chain to be replaced only the top
6746 * most non filter in order to prevent data corruption.
6747 * Another benefit is that this tests exclude backing files which are
6748 * blocked by the backing blockers.
6750 if (!bdrv_recurse_can_replace(parent_bs
, to_replace_bs
)) {
6751 error_setg(errp
, "Cannot replace '%s' by a node mirrored from '%s', "
6752 "because it cannot be guaranteed that doing so would not "
6753 "lead to an abrupt change of visible data",
6754 node_name
, parent_bs
->node_name
);
6755 to_replace_bs
= NULL
;
6760 aio_context_release(aio_context
);
6761 return to_replace_bs
;
6765 * Iterates through the list of runtime option keys that are said to
6766 * be "strong" for a BDS. An option is called "strong" if it changes
6767 * a BDS's data. For example, the null block driver's "size" and
6768 * "read-zeroes" options are strong, but its "latency-ns" option is
6771 * If a key returned by this function ends with a dot, all options
6772 * starting with that prefix are strong.
6774 static const char *const *strong_options(BlockDriverState
*bs
,
6775 const char *const *curopt
)
6777 static const char *const global_options
[] = {
6778 "driver", "filename", NULL
6782 return &global_options
[0];
6786 if (curopt
== &global_options
[ARRAY_SIZE(global_options
) - 1] && bs
->drv
) {
6787 curopt
= bs
->drv
->strong_runtime_opts
;
6790 return (curopt
&& *curopt
) ? curopt
: NULL
;
6794 * Copies all strong runtime options from bs->options to the given
6795 * QDict. The set of strong option keys is determined by invoking
6798 * Returns true iff any strong option was present in bs->options (and
6799 * thus copied to the target QDict) with the exception of "filename"
6800 * and "driver". The caller is expected to use this value to decide
6801 * whether the existence of strong options prevents the generation of
6804 static bool append_strong_runtime_options(QDict
*d
, BlockDriverState
*bs
)
6806 bool found_any
= false;
6807 const char *const *option_name
= NULL
;
6813 while ((option_name
= strong_options(bs
, option_name
))) {
6814 bool option_given
= false;
6816 assert(strlen(*option_name
) > 0);
6817 if ((*option_name
)[strlen(*option_name
) - 1] != '.') {
6818 QObject
*entry
= qdict_get(bs
->options
, *option_name
);
6823 qdict_put_obj(d
, *option_name
, qobject_ref(entry
));
6824 option_given
= true;
6826 const QDictEntry
*entry
;
6827 for (entry
= qdict_first(bs
->options
); entry
;
6828 entry
= qdict_next(bs
->options
, entry
))
6830 if (strstart(qdict_entry_key(entry
), *option_name
, NULL
)) {
6831 qdict_put_obj(d
, qdict_entry_key(entry
),
6832 qobject_ref(qdict_entry_value(entry
)));
6833 option_given
= true;
6838 /* While "driver" and "filename" need to be included in a JSON filename,
6839 * their existence does not prohibit generation of a plain filename. */
6840 if (!found_any
&& option_given
&&
6841 strcmp(*option_name
, "driver") && strcmp(*option_name
, "filename"))
6847 if (!qdict_haskey(d
, "driver")) {
6848 /* Drivers created with bdrv_new_open_driver() may not have a
6849 * @driver option. Add it here. */
6850 qdict_put_str(d
, "driver", bs
->drv
->format_name
);
6856 /* Note: This function may return false positives; it may return true
6857 * even if opening the backing file specified by bs's image header
6858 * would result in exactly bs->backing. */
6859 bool bdrv_backing_overridden(BlockDriverState
*bs
)
6862 return strcmp(bs
->auto_backing_file
,
6863 bs
->backing
->bs
->filename
);
6865 /* No backing BDS, so if the image header reports any backing
6866 * file, it must have been suppressed */
6867 return bs
->auto_backing_file
[0] != '\0';
6871 /* Updates the following BDS fields:
6872 * - exact_filename: A filename which may be used for opening a block device
6873 * which (mostly) equals the given BDS (even without any
6874 * other options; so reading and writing must return the same
6875 * results, but caching etc. may be different)
6876 * - full_open_options: Options which, when given when opening a block device
6877 * (without a filename), result in a BDS (mostly)
6878 * equalling the given one
6879 * - filename: If exact_filename is set, it is copied here. Otherwise,
6880 * full_open_options is converted to a JSON object, prefixed with
6881 * "json:" (for use through the JSON pseudo protocol) and put here.
6883 void bdrv_refresh_filename(BlockDriverState
*bs
)
6885 BlockDriver
*drv
= bs
->drv
;
6887 BlockDriverState
*primary_child_bs
;
6889 bool backing_overridden
;
6890 bool generate_json_filename
; /* Whether our default implementation should
6891 fill exact_filename (false) or not (true) */
6897 /* This BDS's file name may depend on any of its children's file names, so
6898 * refresh those first */
6899 QLIST_FOREACH(child
, &bs
->children
, next
) {
6900 bdrv_refresh_filename(child
->bs
);
6904 /* For implicit nodes, just copy everything from the single child */
6905 child
= QLIST_FIRST(&bs
->children
);
6906 assert(QLIST_NEXT(child
, next
) == NULL
);
6908 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
),
6909 child
->bs
->exact_filename
);
6910 pstrcpy(bs
->filename
, sizeof(bs
->filename
), child
->bs
->filename
);
6912 qobject_unref(bs
->full_open_options
);
6913 bs
->full_open_options
= qobject_ref(child
->bs
->full_open_options
);
6918 backing_overridden
= bdrv_backing_overridden(bs
);
6920 if (bs
->open_flags
& BDRV_O_NO_IO
) {
6921 /* Without I/O, the backing file does not change anything.
6922 * Therefore, in such a case (primarily qemu-img), we can
6923 * pretend the backing file has not been overridden even if
6924 * it technically has been. */
6925 backing_overridden
= false;
6928 /* Gather the options QDict */
6930 generate_json_filename
= append_strong_runtime_options(opts
, bs
);
6931 generate_json_filename
|= backing_overridden
;
6933 if (drv
->bdrv_gather_child_options
) {
6934 /* Some block drivers may not want to present all of their children's
6935 * options, or name them differently from BdrvChild.name */
6936 drv
->bdrv_gather_child_options(bs
, opts
, backing_overridden
);
6938 QLIST_FOREACH(child
, &bs
->children
, next
) {
6939 if (child
== bs
->backing
&& !backing_overridden
) {
6940 /* We can skip the backing BDS if it has not been overridden */
6944 qdict_put(opts
, child
->name
,
6945 qobject_ref(child
->bs
->full_open_options
));
6948 if (backing_overridden
&& !bs
->backing
) {
6949 /* Force no backing file */
6950 qdict_put_null(opts
, "backing");
6954 qobject_unref(bs
->full_open_options
);
6955 bs
->full_open_options
= opts
;
6957 primary_child_bs
= bdrv_primary_bs(bs
);
6959 if (drv
->bdrv_refresh_filename
) {
6960 /* Obsolete information is of no use here, so drop the old file name
6961 * information before refreshing it */
6962 bs
->exact_filename
[0] = '\0';
6964 drv
->bdrv_refresh_filename(bs
);
6965 } else if (primary_child_bs
) {
6967 * Try to reconstruct valid information from the underlying
6968 * file -- this only works for format nodes (filter nodes
6969 * cannot be probed and as such must be selected by the user
6970 * either through an options dict, or through a special
6971 * filename which the filter driver must construct in its
6972 * .bdrv_refresh_filename() implementation).
6975 bs
->exact_filename
[0] = '\0';
6978 * We can use the underlying file's filename if:
6979 * - it has a filename,
6980 * - the current BDS is not a filter,
6981 * - the file is a protocol BDS, and
6982 * - opening that file (as this BDS's format) will automatically create
6983 * the BDS tree we have right now, that is:
6984 * - the user did not significantly change this BDS's behavior with
6985 * some explicit (strong) options
6986 * - no non-file child of this BDS has been overridden by the user
6987 * Both of these conditions are represented by generate_json_filename.
6989 if (primary_child_bs
->exact_filename
[0] &&
6990 primary_child_bs
->drv
->bdrv_file_open
&&
6991 !drv
->is_filter
&& !generate_json_filename
)
6993 strcpy(bs
->exact_filename
, primary_child_bs
->exact_filename
);
6997 if (bs
->exact_filename
[0]) {
6998 pstrcpy(bs
->filename
, sizeof(bs
->filename
), bs
->exact_filename
);
7000 GString
*json
= qobject_to_json(QOBJECT(bs
->full_open_options
));
7001 if (snprintf(bs
->filename
, sizeof(bs
->filename
), "json:%s",
7002 json
->str
) >= sizeof(bs
->filename
)) {
7003 /* Give user a hint if we truncated things. */
7004 strcpy(bs
->filename
+ sizeof(bs
->filename
) - 4, "...");
7006 g_string_free(json
, true);
7010 char *bdrv_dirname(BlockDriverState
*bs
, Error
**errp
)
7012 BlockDriver
*drv
= bs
->drv
;
7013 BlockDriverState
*child_bs
;
7016 error_setg(errp
, "Node '%s' is ejected", bs
->node_name
);
7020 if (drv
->bdrv_dirname
) {
7021 return drv
->bdrv_dirname(bs
, errp
);
7024 child_bs
= bdrv_primary_bs(bs
);
7026 return bdrv_dirname(child_bs
, errp
);
7029 bdrv_refresh_filename(bs
);
7030 if (bs
->exact_filename
[0] != '\0') {
7031 return path_combine(bs
->exact_filename
, "");
7034 error_setg(errp
, "Cannot generate a base directory for %s nodes",
7040 * Hot add/remove a BDS's child. So the user can take a child offline when
7041 * it is broken and take a new child online
7043 void bdrv_add_child(BlockDriverState
*parent_bs
, BlockDriverState
*child_bs
,
7047 if (!parent_bs
->drv
|| !parent_bs
->drv
->bdrv_add_child
) {
7048 error_setg(errp
, "The node %s does not support adding a child",
7049 bdrv_get_device_or_node_name(parent_bs
));
7053 if (!QLIST_EMPTY(&child_bs
->parents
)) {
7054 error_setg(errp
, "The node %s already has a parent",
7055 child_bs
->node_name
);
7059 parent_bs
->drv
->bdrv_add_child(parent_bs
, child_bs
, errp
);
7062 void bdrv_del_child(BlockDriverState
*parent_bs
, BdrvChild
*child
, Error
**errp
)
7066 if (!parent_bs
->drv
|| !parent_bs
->drv
->bdrv_del_child
) {
7067 error_setg(errp
, "The node %s does not support removing a child",
7068 bdrv_get_device_or_node_name(parent_bs
));
7072 QLIST_FOREACH(tmp
, &parent_bs
->children
, next
) {
7079 error_setg(errp
, "The node %s does not have a child named %s",
7080 bdrv_get_device_or_node_name(parent_bs
),
7081 bdrv_get_device_or_node_name(child
->bs
));
7085 parent_bs
->drv
->bdrv_del_child(parent_bs
, child
, errp
);
7088 int bdrv_make_empty(BdrvChild
*c
, Error
**errp
)
7090 BlockDriver
*drv
= c
->bs
->drv
;
7093 assert(c
->perm
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
));
7095 if (!drv
->bdrv_make_empty
) {
7096 error_setg(errp
, "%s does not support emptying nodes",
7101 ret
= drv
->bdrv_make_empty(c
->bs
);
7103 error_setg_errno(errp
, -ret
, "Failed to empty %s",
7112 * Return the child that @bs acts as an overlay for, and from which data may be
7113 * copied in COW or COR operations. Usually this is the backing file.
7115 BdrvChild
*bdrv_cow_child(BlockDriverState
*bs
)
7117 if (!bs
|| !bs
->drv
) {
7121 if (bs
->drv
->is_filter
) {
7129 assert(bs
->backing
->role
& BDRV_CHILD_COW
);
7134 * If @bs acts as a filter for exactly one of its children, return
7137 BdrvChild
*bdrv_filter_child(BlockDriverState
*bs
)
7141 if (!bs
|| !bs
->drv
) {
7145 if (!bs
->drv
->is_filter
) {
7149 /* Only one of @backing or @file may be used */
7150 assert(!(bs
->backing
&& bs
->file
));
7152 c
= bs
->backing
?: bs
->file
;
7157 assert(c
->role
& BDRV_CHILD_FILTERED
);
7162 * Return either the result of bdrv_cow_child() or bdrv_filter_child(),
7163 * whichever is non-NULL.
7165 * Return NULL if both are NULL.
7167 BdrvChild
*bdrv_filter_or_cow_child(BlockDriverState
*bs
)
7169 BdrvChild
*cow_child
= bdrv_cow_child(bs
);
7170 BdrvChild
*filter_child
= bdrv_filter_child(bs
);
7172 /* Filter nodes cannot have COW backing files */
7173 assert(!(cow_child
&& filter_child
));
7175 return cow_child
?: filter_child
;
7179 * Return the primary child of this node: For filters, that is the
7180 * filtered child. For other nodes, that is usually the child storing
7182 * (A generally more helpful description is that this is (usually) the
7183 * child that has the same filename as @bs.)
7185 * Drivers do not necessarily have a primary child; for example quorum
7188 BdrvChild
*bdrv_primary_child(BlockDriverState
*bs
)
7190 BdrvChild
*c
, *found
= NULL
;
7192 QLIST_FOREACH(c
, &bs
->children
, next
) {
7193 if (c
->role
& BDRV_CHILD_PRIMARY
) {
7202 static BlockDriverState
*bdrv_do_skip_filters(BlockDriverState
*bs
,
7203 bool stop_on_explicit_filter
)
7211 while (!(stop_on_explicit_filter
&& !bs
->implicit
)) {
7212 c
= bdrv_filter_child(bs
);
7215 * A filter that is embedded in a working block graph must
7216 * have a child. Assert this here so this function does
7217 * not return a filter node that is not expected by the
7220 assert(!bs
->drv
|| !bs
->drv
->is_filter
);
7226 * Note that this treats nodes with bs->drv == NULL as not being
7227 * filters (bs->drv == NULL should be replaced by something else
7229 * The advantage of this behavior is that this function will thus
7230 * always return a non-NULL value (given a non-NULL @bs).
7237 * Return the first BDS that has not been added implicitly or that
7238 * does not have a filtered child down the chain starting from @bs
7239 * (including @bs itself).
7241 BlockDriverState
*bdrv_skip_implicit_filters(BlockDriverState
*bs
)
7243 return bdrv_do_skip_filters(bs
, true);
7247 * Return the first BDS that does not have a filtered child down the
7248 * chain starting from @bs (including @bs itself).
7250 BlockDriverState
*bdrv_skip_filters(BlockDriverState
*bs
)
7252 return bdrv_do_skip_filters(bs
, false);
7256 * For a backing chain, return the first non-filter backing image of
7257 * the first non-filter image.
7259 BlockDriverState
*bdrv_backing_chain_next(BlockDriverState
*bs
)
7261 return bdrv_skip_filters(bdrv_cow_bs(bdrv_skip_filters(bs
)));