2 * QEMU System Emulator block driver
4 * Copyright (c) 2003 Fabrice Bellard
5 * Copyright (c) 2020 Virtuozzo International GmbH.
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26 #include "qemu/osdep.h"
27 #include "block/trace.h"
28 #include "block/block_int.h"
29 #include "block/blockjob.h"
30 #include "block/fuse.h"
31 #include "block/nbd.h"
32 #include "block/qdict.h"
33 #include "qemu/error-report.h"
34 #include "block/module_block.h"
35 #include "qemu/main-loop.h"
36 #include "qemu/module.h"
37 #include "qapi/error.h"
38 #include "qapi/qmp/qdict.h"
39 #include "qapi/qmp/qjson.h"
40 #include "qapi/qmp/qnull.h"
41 #include "qapi/qmp/qstring.h"
42 #include "qapi/qobject-output-visitor.h"
43 #include "qapi/qapi-visit-block-core.h"
44 #include "sysemu/block-backend.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 "qemu/range.h"
54 #include "block/coroutines.h"
57 #include <sys/ioctl.h>
58 #include <sys/queue.h>
59 #if defined(HAVE_SYS_DISK_H)
68 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
70 static QTAILQ_HEAD(, BlockDriverState
) graph_bdrv_states
=
71 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states
);
73 static QTAILQ_HEAD(, BlockDriverState
) all_bdrv_states
=
74 QTAILQ_HEAD_INITIALIZER(all_bdrv_states
);
76 static QLIST_HEAD(, BlockDriver
) bdrv_drivers
=
77 QLIST_HEAD_INITIALIZER(bdrv_drivers
);
79 static BlockDriverState
*bdrv_open_inherit(const char *filename
,
80 const char *reference
,
81 QDict
*options
, int flags
,
82 BlockDriverState
*parent
,
83 const BdrvChildClass
*child_class
,
84 BdrvChildRole child_role
,
87 static bool bdrv_recurse_has_child(BlockDriverState
*bs
,
88 BlockDriverState
*child
);
90 static void bdrv_replace_child_noperm(BdrvChild
**child
,
91 BlockDriverState
*new_bs
);
92 static void bdrv_remove_file_or_backing_child(BlockDriverState
*bs
,
95 static void bdrv_remove_filter_or_cow_child(BlockDriverState
*bs
,
98 static int bdrv_reopen_prepare(BDRVReopenState
*reopen_state
,
99 BlockReopenQueue
*queue
,
100 Transaction
*change_child_tran
, Error
**errp
);
101 static void bdrv_reopen_commit(BDRVReopenState
*reopen_state
);
102 static void bdrv_reopen_abort(BDRVReopenState
*reopen_state
);
104 /* If non-zero, use only whitelisted block drivers */
105 static int use_bdrv_whitelist
;
108 static int is_windows_drive_prefix(const char *filename
)
110 return (((filename
[0] >= 'a' && filename
[0] <= 'z') ||
111 (filename
[0] >= 'A' && filename
[0] <= 'Z')) &&
115 int is_windows_drive(const char *filename
)
117 if (is_windows_drive_prefix(filename
) &&
120 if (strstart(filename
, "\\\\.\\", NULL
) ||
121 strstart(filename
, "//./", NULL
))
127 size_t bdrv_opt_mem_align(BlockDriverState
*bs
)
129 if (!bs
|| !bs
->drv
) {
130 /* page size or 4k (hdd sector size) should be on the safe side */
131 return MAX(4096, qemu_real_host_page_size
);
134 return bs
->bl
.opt_mem_alignment
;
137 size_t bdrv_min_mem_align(BlockDriverState
*bs
)
139 if (!bs
|| !bs
->drv
) {
140 /* page size or 4k (hdd sector size) should be on the safe side */
141 return MAX(4096, qemu_real_host_page_size
);
144 return bs
->bl
.min_mem_alignment
;
147 /* check if the path starts with "<protocol>:" */
148 int path_has_protocol(const char *path
)
153 if (is_windows_drive(path
) ||
154 is_windows_drive_prefix(path
)) {
157 p
= path
+ strcspn(path
, ":/\\");
159 p
= path
+ strcspn(path
, ":/");
165 int path_is_absolute(const char *path
)
168 /* specific case for names like: "\\.\d:" */
169 if (is_windows_drive(path
) || is_windows_drive_prefix(path
)) {
172 return (*path
== '/' || *path
== '\\');
174 return (*path
== '/');
178 /* if filename is absolute, just return its duplicate. Otherwise, build a
179 path to it by considering it is relative to base_path. URL are
181 char *path_combine(const char *base_path
, const char *filename
)
183 const char *protocol_stripped
= NULL
;
188 if (path_is_absolute(filename
)) {
189 return g_strdup(filename
);
192 if (path_has_protocol(base_path
)) {
193 protocol_stripped
= strchr(base_path
, ':');
194 if (protocol_stripped
) {
198 p
= protocol_stripped
?: base_path
;
200 p1
= strrchr(base_path
, '/');
204 p2
= strrchr(base_path
, '\\');
205 if (!p1
|| p2
> p1
) {
220 result
= g_malloc(len
+ strlen(filename
) + 1);
221 memcpy(result
, base_path
, len
);
222 strcpy(result
+ len
, filename
);
228 * Helper function for bdrv_parse_filename() implementations to remove optional
229 * protocol prefixes (especially "file:") from a filename and for putting the
230 * stripped filename into the options QDict if there is such a prefix.
232 void bdrv_parse_filename_strip_prefix(const char *filename
, const char *prefix
,
235 if (strstart(filename
, prefix
, &filename
)) {
236 /* Stripping the explicit protocol prefix may result in a protocol
237 * prefix being (wrongly) detected (if the filename contains a colon) */
238 if (path_has_protocol(filename
)) {
239 GString
*fat_filename
;
241 /* This means there is some colon before the first slash; therefore,
242 * this cannot be an absolute path */
243 assert(!path_is_absolute(filename
));
245 /* And we can thus fix the protocol detection issue by prefixing it
247 fat_filename
= g_string_new("./");
248 g_string_append(fat_filename
, filename
);
250 assert(!path_has_protocol(fat_filename
->str
));
252 qdict_put(options
, "filename",
253 qstring_from_gstring(fat_filename
));
255 /* If no protocol prefix was detected, we can use the shortened
257 qdict_put_str(options
, "filename", filename
);
263 /* Returns whether the image file is opened as read-only. Note that this can
264 * return false and writing to the image file is still not possible because the
265 * image is inactivated. */
266 bool bdrv_is_read_only(BlockDriverState
*bs
)
268 return !(bs
->open_flags
& BDRV_O_RDWR
);
271 int bdrv_can_set_read_only(BlockDriverState
*bs
, bool read_only
,
272 bool ignore_allow_rdw
, Error
**errp
)
274 /* Do not set read_only if copy_on_read is enabled */
275 if (bs
->copy_on_read
&& read_only
) {
276 error_setg(errp
, "Can't set node '%s' to r/o with copy-on-read enabled",
277 bdrv_get_device_or_node_name(bs
));
281 /* Do not clear read_only if it is prohibited */
282 if (!read_only
&& !(bs
->open_flags
& BDRV_O_ALLOW_RDWR
) &&
285 error_setg(errp
, "Node '%s' is read only",
286 bdrv_get_device_or_node_name(bs
));
294 * Called by a driver that can only provide a read-only image.
296 * Returns 0 if the node is already read-only or it could switch the node to
297 * read-only because BDRV_O_AUTO_RDONLY is set.
299 * Returns -EACCES if the node is read-write and BDRV_O_AUTO_RDONLY is not set
300 * or bdrv_can_set_read_only() forbids making the node read-only. If @errmsg
301 * is not NULL, it is used as the error message for the Error object.
303 int bdrv_apply_auto_read_only(BlockDriverState
*bs
, const char *errmsg
,
308 if (!(bs
->open_flags
& BDRV_O_RDWR
)) {
311 if (!(bs
->open_flags
& BDRV_O_AUTO_RDONLY
)) {
315 ret
= bdrv_can_set_read_only(bs
, true, false, NULL
);
320 bs
->open_flags
&= ~BDRV_O_RDWR
;
325 error_setg(errp
, "%s", errmsg
?: "Image is read-only");
330 * If @backing is empty, this function returns NULL without setting
331 * @errp. In all other cases, NULL will only be returned with @errp
334 * Therefore, a return value of NULL without @errp set means that
335 * there is no backing file; if @errp is set, there is one but its
336 * absolute filename cannot be generated.
338 char *bdrv_get_full_backing_filename_from_filename(const char *backed
,
342 if (backing
[0] == '\0') {
344 } else if (path_has_protocol(backing
) || path_is_absolute(backing
)) {
345 return g_strdup(backing
);
346 } else if (backed
[0] == '\0' || strstart(backed
, "json:", NULL
)) {
347 error_setg(errp
, "Cannot use relative backing file names for '%s'",
351 return path_combine(backed
, backing
);
356 * If @filename is empty or NULL, this function returns NULL without
357 * setting @errp. In all other cases, NULL will only be returned with
360 static char *bdrv_make_absolute_filename(BlockDriverState
*relative_to
,
361 const char *filename
, Error
**errp
)
363 char *dir
, *full_name
;
365 if (!filename
|| filename
[0] == '\0') {
367 } else if (path_has_protocol(filename
) || path_is_absolute(filename
)) {
368 return g_strdup(filename
);
371 dir
= bdrv_dirname(relative_to
, errp
);
376 full_name
= g_strconcat(dir
, filename
, NULL
);
381 char *bdrv_get_full_backing_filename(BlockDriverState
*bs
, Error
**errp
)
383 return bdrv_make_absolute_filename(bs
, bs
->backing_file
, errp
);
386 void bdrv_register(BlockDriver
*bdrv
)
388 assert(bdrv
->format_name
);
389 QLIST_INSERT_HEAD(&bdrv_drivers
, bdrv
, list
);
392 BlockDriverState
*bdrv_new(void)
394 BlockDriverState
*bs
;
397 bs
= g_new0(BlockDriverState
, 1);
398 QLIST_INIT(&bs
->dirty_bitmaps
);
399 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
400 QLIST_INIT(&bs
->op_blockers
[i
]);
402 qemu_co_mutex_init(&bs
->reqs_lock
);
403 qemu_mutex_init(&bs
->dirty_bitmap_mutex
);
405 bs
->aio_context
= qemu_get_aio_context();
407 qemu_co_queue_init(&bs
->flush_queue
);
409 qemu_co_mutex_init(&bs
->bsc_modify_lock
);
410 bs
->block_status_cache
= g_new0(BdrvBlockStatusCache
, 1);
412 for (i
= 0; i
< bdrv_drain_all_count
; i
++) {
413 bdrv_drained_begin(bs
);
416 QTAILQ_INSERT_TAIL(&all_bdrv_states
, bs
, bs_list
);
421 static BlockDriver
*bdrv_do_find_format(const char *format_name
)
425 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
426 if (!strcmp(drv1
->format_name
, format_name
)) {
434 BlockDriver
*bdrv_find_format(const char *format_name
)
439 drv1
= bdrv_do_find_format(format_name
);
444 /* The driver isn't registered, maybe we need to load a module */
445 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
446 if (!strcmp(block_driver_modules
[i
].format_name
, format_name
)) {
447 block_module_load_one(block_driver_modules
[i
].library_name
);
452 return bdrv_do_find_format(format_name
);
455 static int bdrv_format_is_whitelisted(const char *format_name
, bool read_only
)
457 static const char *whitelist_rw
[] = {
458 CONFIG_BDRV_RW_WHITELIST
461 static const char *whitelist_ro
[] = {
462 CONFIG_BDRV_RO_WHITELIST
467 if (!whitelist_rw
[0] && !whitelist_ro
[0]) {
468 return 1; /* no whitelist, anything goes */
471 for (p
= whitelist_rw
; *p
; p
++) {
472 if (!strcmp(format_name
, *p
)) {
477 for (p
= whitelist_ro
; *p
; p
++) {
478 if (!strcmp(format_name
, *p
)) {
486 int bdrv_is_whitelisted(BlockDriver
*drv
, bool read_only
)
488 return bdrv_format_is_whitelisted(drv
->format_name
, read_only
);
491 bool bdrv_uses_whitelist(void)
493 return use_bdrv_whitelist
;
496 typedef struct CreateCo
{
504 static void coroutine_fn
bdrv_create_co_entry(void *opaque
)
506 Error
*local_err
= NULL
;
509 CreateCo
*cco
= opaque
;
512 ret
= cco
->drv
->bdrv_co_create_opts(cco
->drv
,
513 cco
->filename
, cco
->opts
, &local_err
);
514 error_propagate(&cco
->err
, local_err
);
518 int bdrv_create(BlockDriver
*drv
, const char* filename
,
519 QemuOpts
*opts
, Error
**errp
)
526 .filename
= g_strdup(filename
),
532 if (!drv
->bdrv_co_create_opts
) {
533 error_setg(errp
, "Driver '%s' does not support image creation", drv
->format_name
);
538 if (qemu_in_coroutine()) {
539 /* Fast-path if already in coroutine context */
540 bdrv_create_co_entry(&cco
);
542 co
= qemu_coroutine_create(bdrv_create_co_entry
, &cco
);
543 qemu_coroutine_enter(co
);
544 while (cco
.ret
== NOT_DONE
) {
545 aio_poll(qemu_get_aio_context(), true);
552 error_propagate(errp
, cco
.err
);
554 error_setg_errno(errp
, -ret
, "Could not create image");
559 g_free(cco
.filename
);
564 * Helper function for bdrv_create_file_fallback(): Resize @blk to at
565 * least the given @minimum_size.
567 * On success, return @blk's actual length.
568 * Otherwise, return -errno.
570 static int64_t create_file_fallback_truncate(BlockBackend
*blk
,
571 int64_t minimum_size
, Error
**errp
)
573 Error
*local_err
= NULL
;
577 ret
= blk_truncate(blk
, minimum_size
, false, PREALLOC_MODE_OFF
, 0,
579 if (ret
< 0 && ret
!= -ENOTSUP
) {
580 error_propagate(errp
, local_err
);
584 size
= blk_getlength(blk
);
586 error_free(local_err
);
587 error_setg_errno(errp
, -size
,
588 "Failed to inquire the new image file's length");
592 if (size
< minimum_size
) {
593 /* Need to grow the image, but we failed to do that */
594 error_propagate(errp
, local_err
);
598 error_free(local_err
);
605 * Helper function for bdrv_create_file_fallback(): Zero the first
606 * sector to remove any potentially pre-existing image header.
608 static int create_file_fallback_zero_first_sector(BlockBackend
*blk
,
609 int64_t current_size
,
612 int64_t bytes_to_clear
;
615 bytes_to_clear
= MIN(current_size
, BDRV_SECTOR_SIZE
);
616 if (bytes_to_clear
) {
617 ret
= blk_pwrite_zeroes(blk
, 0, bytes_to_clear
, BDRV_REQ_MAY_UNMAP
);
619 error_setg_errno(errp
, -ret
,
620 "Failed to clear the new image's first sector");
629 * Simple implementation of bdrv_co_create_opts for protocol drivers
630 * which only support creation via opening a file
631 * (usually existing raw storage device)
633 int coroutine_fn
bdrv_co_create_opts_simple(BlockDriver
*drv
,
634 const char *filename
,
642 PreallocMode prealloc
;
643 Error
*local_err
= NULL
;
646 size
= qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0);
647 buf
= qemu_opt_get_del(opts
, BLOCK_OPT_PREALLOC
);
648 prealloc
= qapi_enum_parse(&PreallocMode_lookup
, buf
,
649 PREALLOC_MODE_OFF
, &local_err
);
652 error_propagate(errp
, local_err
);
656 if (prealloc
!= PREALLOC_MODE_OFF
) {
657 error_setg(errp
, "Unsupported preallocation mode '%s'",
658 PreallocMode_str(prealloc
));
662 options
= qdict_new();
663 qdict_put_str(options
, "driver", drv
->format_name
);
665 blk
= blk_new_open(filename
, NULL
, options
,
666 BDRV_O_RDWR
| BDRV_O_RESIZE
, errp
);
668 error_prepend(errp
, "Protocol driver '%s' does not support image "
669 "creation, and opening the image failed: ",
674 size
= create_file_fallback_truncate(blk
, size
, errp
);
680 ret
= create_file_fallback_zero_first_sector(blk
, size
, errp
);
691 int bdrv_create_file(const char *filename
, QemuOpts
*opts
, Error
**errp
)
693 QemuOpts
*protocol_opts
;
698 drv
= bdrv_find_protocol(filename
, true, errp
);
703 if (!drv
->create_opts
) {
704 error_setg(errp
, "Driver '%s' does not support image creation",
710 * 'opts' contains a QemuOptsList with a combination of format and protocol
713 * The format properly removes its options, but the default values remain
714 * in 'opts->list'. So if the protocol has options with the same name
715 * (e.g. rbd has 'cluster_size' as qcow2), it will see the default values
716 * of the format, since for overlapping options, the format wins.
718 * To avoid this issue, lets convert QemuOpts to QDict, in this way we take
719 * only the set options, and then convert it back to QemuOpts, using the
720 * create_opts of the protocol. So the new QemuOpts, will contain only the
723 qdict
= qemu_opts_to_qdict(opts
, NULL
);
724 protocol_opts
= qemu_opts_from_qdict(drv
->create_opts
, qdict
, errp
);
725 if (protocol_opts
== NULL
) {
730 ret
= bdrv_create(drv
, filename
, protocol_opts
, errp
);
732 qemu_opts_del(protocol_opts
);
733 qobject_unref(qdict
);
737 int coroutine_fn
bdrv_co_delete_file(BlockDriverState
*bs
, Error
**errp
)
739 Error
*local_err
= NULL
;
745 error_setg(errp
, "Block node '%s' is not opened", bs
->filename
);
749 if (!bs
->drv
->bdrv_co_delete_file
) {
750 error_setg(errp
, "Driver '%s' does not support image deletion",
751 bs
->drv
->format_name
);
755 ret
= bs
->drv
->bdrv_co_delete_file(bs
, &local_err
);
757 error_propagate(errp
, local_err
);
763 void coroutine_fn
bdrv_co_delete_file_noerr(BlockDriverState
*bs
)
765 Error
*local_err
= NULL
;
772 ret
= bdrv_co_delete_file(bs
, &local_err
);
774 * ENOTSUP will happen if the block driver doesn't support
775 * the 'bdrv_co_delete_file' interface. This is a predictable
776 * scenario and shouldn't be reported back to the user.
778 if (ret
== -ENOTSUP
) {
779 error_free(local_err
);
780 } else if (ret
< 0) {
781 error_report_err(local_err
);
786 * Try to get @bs's logical and physical block size.
787 * On success, store them in @bsz struct and return 0.
788 * On failure return -errno.
789 * @bs must not be empty.
791 int bdrv_probe_blocksizes(BlockDriverState
*bs
, BlockSizes
*bsz
)
793 BlockDriver
*drv
= bs
->drv
;
794 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
796 if (drv
&& drv
->bdrv_probe_blocksizes
) {
797 return drv
->bdrv_probe_blocksizes(bs
, bsz
);
798 } else if (filtered
) {
799 return bdrv_probe_blocksizes(filtered
, bsz
);
806 * Try to get @bs's geometry (cyls, heads, sectors).
807 * On success, store them in @geo struct and return 0.
808 * On failure return -errno.
809 * @bs must not be empty.
811 int bdrv_probe_geometry(BlockDriverState
*bs
, HDGeometry
*geo
)
813 BlockDriver
*drv
= bs
->drv
;
814 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
816 if (drv
&& drv
->bdrv_probe_geometry
) {
817 return drv
->bdrv_probe_geometry(bs
, geo
);
818 } else if (filtered
) {
819 return bdrv_probe_geometry(filtered
, geo
);
826 * Create a uniquely-named empty temporary file.
827 * Return 0 upon success, otherwise a negative errno value.
829 int get_tmp_filename(char *filename
, int size
)
832 char temp_dir
[MAX_PATH
];
833 /* GetTempFileName requires that its output buffer (4th param)
834 have length MAX_PATH or greater. */
835 assert(size
>= MAX_PATH
);
836 return (GetTempPath(MAX_PATH
, temp_dir
)
837 && GetTempFileName(temp_dir
, "qem", 0, filename
)
838 ? 0 : -GetLastError());
842 tmpdir
= getenv("TMPDIR");
846 if (snprintf(filename
, size
, "%s/vl.XXXXXX", tmpdir
) >= size
) {
849 fd
= mkstemp(filename
);
853 if (close(fd
) != 0) {
862 * Detect host devices. By convention, /dev/cdrom[N] is always
863 * recognized as a host CDROM.
865 static BlockDriver
*find_hdev_driver(const char *filename
)
867 int score_max
= 0, score
;
868 BlockDriver
*drv
= NULL
, *d
;
870 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
871 if (d
->bdrv_probe_device
) {
872 score
= d
->bdrv_probe_device(filename
);
873 if (score
> score_max
) {
883 static BlockDriver
*bdrv_do_find_protocol(const char *protocol
)
887 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
888 if (drv1
->protocol_name
&& !strcmp(drv1
->protocol_name
, protocol
)) {
896 BlockDriver
*bdrv_find_protocol(const char *filename
,
897 bool allow_protocol_prefix
,
906 /* TODO Drivers without bdrv_file_open must be specified explicitly */
909 * XXX(hch): we really should not let host device detection
910 * override an explicit protocol specification, but moving this
911 * later breaks access to device names with colons in them.
912 * Thanks to the brain-dead persistent naming schemes on udev-
913 * based Linux systems those actually are quite common.
915 drv1
= find_hdev_driver(filename
);
920 if (!path_has_protocol(filename
) || !allow_protocol_prefix
) {
924 p
= strchr(filename
, ':');
927 if (len
> sizeof(protocol
) - 1)
928 len
= sizeof(protocol
) - 1;
929 memcpy(protocol
, filename
, len
);
930 protocol
[len
] = '\0';
932 drv1
= bdrv_do_find_protocol(protocol
);
937 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
938 if (block_driver_modules
[i
].protocol_name
&&
939 !strcmp(block_driver_modules
[i
].protocol_name
, protocol
)) {
940 block_module_load_one(block_driver_modules
[i
].library_name
);
945 drv1
= bdrv_do_find_protocol(protocol
);
947 error_setg(errp
, "Unknown protocol '%s'", protocol
);
953 * Guess image format by probing its contents.
954 * This is not a good idea when your image is raw (CVE-2008-2004), but
955 * we do it anyway for backward compatibility.
957 * @buf contains the image's first @buf_size bytes.
958 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
959 * but can be smaller if the image file is smaller)
960 * @filename is its filename.
962 * For all block drivers, call the bdrv_probe() method to get its
964 * Return the first block driver with the highest probing score.
966 BlockDriver
*bdrv_probe_all(const uint8_t *buf
, int buf_size
,
967 const char *filename
)
969 int score_max
= 0, score
;
970 BlockDriver
*drv
= NULL
, *d
;
972 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
974 score
= d
->bdrv_probe(buf
, buf_size
, filename
);
975 if (score
> score_max
) {
985 static int find_image_format(BlockBackend
*file
, const char *filename
,
986 BlockDriver
**pdrv
, Error
**errp
)
989 uint8_t buf
[BLOCK_PROBE_BUF_SIZE
];
992 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
993 if (blk_is_sg(file
) || !blk_is_inserted(file
) || blk_getlength(file
) == 0) {
998 ret
= blk_pread(file
, 0, buf
, sizeof(buf
));
1000 error_setg_errno(errp
, -ret
, "Could not read image for determining its "
1006 drv
= bdrv_probe_all(buf
, ret
, filename
);
1008 error_setg(errp
, "Could not determine image format: No compatible "
1017 * Set the current 'total_sectors' value
1018 * Return 0 on success, -errno on error.
1020 int refresh_total_sectors(BlockDriverState
*bs
, int64_t hint
)
1022 BlockDriver
*drv
= bs
->drv
;
1028 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
1032 /* query actual device if possible, otherwise just trust the hint */
1033 if (drv
->bdrv_getlength
) {
1034 int64_t length
= drv
->bdrv_getlength(bs
);
1038 hint
= DIV_ROUND_UP(length
, BDRV_SECTOR_SIZE
);
1041 bs
->total_sectors
= hint
;
1043 if (bs
->total_sectors
* BDRV_SECTOR_SIZE
> BDRV_MAX_LENGTH
) {
1051 * Combines a QDict of new block driver @options with any missing options taken
1052 * from @old_options, so that leaving out an option defaults to its old value.
1054 static void bdrv_join_options(BlockDriverState
*bs
, QDict
*options
,
1057 if (bs
->drv
&& bs
->drv
->bdrv_join_options
) {
1058 bs
->drv
->bdrv_join_options(options
, old_options
);
1060 qdict_join(options
, old_options
, false);
1064 static BlockdevDetectZeroesOptions
bdrv_parse_detect_zeroes(QemuOpts
*opts
,
1068 Error
*local_err
= NULL
;
1069 char *value
= qemu_opt_get_del(opts
, "detect-zeroes");
1070 BlockdevDetectZeroesOptions detect_zeroes
=
1071 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup
, value
,
1072 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF
, &local_err
);
1075 error_propagate(errp
, local_err
);
1076 return detect_zeroes
;
1079 if (detect_zeroes
== BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP
&&
1080 !(open_flags
& BDRV_O_UNMAP
))
1082 error_setg(errp
, "setting detect-zeroes to unmap is not allowed "
1083 "without setting discard operation to unmap");
1086 return detect_zeroes
;
1090 * Set open flags for aio engine
1092 * Return 0 on success, -1 if the engine specified is invalid
1094 int bdrv_parse_aio(const char *mode
, int *flags
)
1096 if (!strcmp(mode
, "threads")) {
1097 /* do nothing, default */
1098 } else if (!strcmp(mode
, "native")) {
1099 *flags
|= BDRV_O_NATIVE_AIO
;
1100 #ifdef CONFIG_LINUX_IO_URING
1101 } else if (!strcmp(mode
, "io_uring")) {
1102 *flags
|= BDRV_O_IO_URING
;
1112 * Set open flags for a given discard mode
1114 * Return 0 on success, -1 if the discard mode was invalid.
1116 int bdrv_parse_discard_flags(const char *mode
, int *flags
)
1118 *flags
&= ~BDRV_O_UNMAP
;
1120 if (!strcmp(mode
, "off") || !strcmp(mode
, "ignore")) {
1122 } else if (!strcmp(mode
, "on") || !strcmp(mode
, "unmap")) {
1123 *flags
|= BDRV_O_UNMAP
;
1132 * Set open flags for a given cache mode
1134 * Return 0 on success, -1 if the cache mode was invalid.
1136 int bdrv_parse_cache_mode(const char *mode
, int *flags
, bool *writethrough
)
1138 *flags
&= ~BDRV_O_CACHE_MASK
;
1140 if (!strcmp(mode
, "off") || !strcmp(mode
, "none")) {
1141 *writethrough
= false;
1142 *flags
|= BDRV_O_NOCACHE
;
1143 } else if (!strcmp(mode
, "directsync")) {
1144 *writethrough
= true;
1145 *flags
|= BDRV_O_NOCACHE
;
1146 } else if (!strcmp(mode
, "writeback")) {
1147 *writethrough
= false;
1148 } else if (!strcmp(mode
, "unsafe")) {
1149 *writethrough
= false;
1150 *flags
|= BDRV_O_NO_FLUSH
;
1151 } else if (!strcmp(mode
, "writethrough")) {
1152 *writethrough
= true;
1160 static char *bdrv_child_get_parent_desc(BdrvChild
*c
)
1162 BlockDriverState
*parent
= c
->opaque
;
1163 return g_strdup_printf("node '%s'", bdrv_get_node_name(parent
));
1166 static void bdrv_child_cb_drained_begin(BdrvChild
*child
)
1168 BlockDriverState
*bs
= child
->opaque
;
1169 bdrv_do_drained_begin_quiesce(bs
, NULL
, false);
1172 static bool bdrv_child_cb_drained_poll(BdrvChild
*child
)
1174 BlockDriverState
*bs
= child
->opaque
;
1175 return bdrv_drain_poll(bs
, false, NULL
, false);
1178 static void bdrv_child_cb_drained_end(BdrvChild
*child
,
1179 int *drained_end_counter
)
1181 BlockDriverState
*bs
= child
->opaque
;
1182 bdrv_drained_end_no_poll(bs
, drained_end_counter
);
1185 static int bdrv_child_cb_inactivate(BdrvChild
*child
)
1187 BlockDriverState
*bs
= child
->opaque
;
1188 assert(bs
->open_flags
& BDRV_O_INACTIVE
);
1192 static bool bdrv_child_cb_can_set_aio_ctx(BdrvChild
*child
, AioContext
*ctx
,
1193 GSList
**ignore
, Error
**errp
)
1195 BlockDriverState
*bs
= child
->opaque
;
1196 return bdrv_can_set_aio_context(bs
, ctx
, ignore
, errp
);
1199 static void bdrv_child_cb_set_aio_ctx(BdrvChild
*child
, AioContext
*ctx
,
1202 BlockDriverState
*bs
= child
->opaque
;
1203 return bdrv_set_aio_context_ignore(bs
, ctx
, ignore
);
1207 * Returns the options and flags that a temporary snapshot should get, based on
1208 * the originally requested flags (the originally requested image will have
1209 * flags like a backing file)
1211 static void bdrv_temp_snapshot_options(int *child_flags
, QDict
*child_options
,
1212 int parent_flags
, QDict
*parent_options
)
1214 *child_flags
= (parent_flags
& ~BDRV_O_SNAPSHOT
) | BDRV_O_TEMPORARY
;
1216 /* For temporary files, unconditional cache=unsafe is fine */
1217 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_DIRECT
, "off");
1218 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_NO_FLUSH
, "on");
1220 /* Copy the read-only and discard options from the parent */
1221 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1222 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_DISCARD
);
1224 /* aio=native doesn't work for cache.direct=off, so disable it for the
1225 * temporary snapshot */
1226 *child_flags
&= ~BDRV_O_NATIVE_AIO
;
1229 static void bdrv_backing_attach(BdrvChild
*c
)
1231 BlockDriverState
*parent
= c
->opaque
;
1232 BlockDriverState
*backing_hd
= c
->bs
;
1234 assert(!parent
->backing_blocker
);
1235 error_setg(&parent
->backing_blocker
,
1236 "node is used as backing hd of '%s'",
1237 bdrv_get_device_or_node_name(parent
));
1239 bdrv_refresh_filename(backing_hd
);
1241 parent
->open_flags
&= ~BDRV_O_NO_BACKING
;
1243 bdrv_op_block_all(backing_hd
, parent
->backing_blocker
);
1244 /* Otherwise we won't be able to commit or stream */
1245 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_COMMIT_TARGET
,
1246 parent
->backing_blocker
);
1247 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_STREAM
,
1248 parent
->backing_blocker
);
1250 * We do backup in 3 ways:
1252 * The target bs is new opened, and the source is top BDS
1253 * 2. blockdev backup
1254 * Both the source and the target are top BDSes.
1255 * 3. internal backup(used for block replication)
1256 * Both the source and the target are backing file
1258 * In case 1 and 2, neither the source nor the target is the backing file.
1259 * In case 3, we will block the top BDS, so there is only one block job
1260 * for the top BDS and its backing chain.
1262 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_SOURCE
,
1263 parent
->backing_blocker
);
1264 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_TARGET
,
1265 parent
->backing_blocker
);
1268 static void bdrv_backing_detach(BdrvChild
*c
)
1270 BlockDriverState
*parent
= c
->opaque
;
1272 assert(parent
->backing_blocker
);
1273 bdrv_op_unblock_all(c
->bs
, parent
->backing_blocker
);
1274 error_free(parent
->backing_blocker
);
1275 parent
->backing_blocker
= NULL
;
1278 static int bdrv_backing_update_filename(BdrvChild
*c
, BlockDriverState
*base
,
1279 const char *filename
, Error
**errp
)
1281 BlockDriverState
*parent
= c
->opaque
;
1282 bool read_only
= bdrv_is_read_only(parent
);
1286 ret
= bdrv_reopen_set_read_only(parent
, false, errp
);
1292 ret
= bdrv_change_backing_file(parent
, filename
,
1293 base
->drv
? base
->drv
->format_name
: "",
1296 error_setg_errno(errp
, -ret
, "Could not update backing file link");
1300 bdrv_reopen_set_read_only(parent
, true, NULL
);
1307 * Returns the options and flags that a generic child of a BDS should
1308 * get, based on the given options and flags for the parent BDS.
1310 static void bdrv_inherited_options(BdrvChildRole role
, bool parent_is_format
,
1311 int *child_flags
, QDict
*child_options
,
1312 int parent_flags
, QDict
*parent_options
)
1314 int flags
= parent_flags
;
1317 * First, decide whether to set, clear, or leave BDRV_O_PROTOCOL.
1318 * Generally, the question to answer is: Should this child be
1319 * format-probed by default?
1323 * Pure and non-filtered data children of non-format nodes should
1324 * be probed by default (even when the node itself has BDRV_O_PROTOCOL
1325 * set). This only affects a very limited set of drivers (namely
1326 * quorum and blkverify when this comment was written).
1327 * Force-clear BDRV_O_PROTOCOL then.
1329 if (!parent_is_format
&&
1330 (role
& BDRV_CHILD_DATA
) &&
1331 !(role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_FILTERED
)))
1333 flags
&= ~BDRV_O_PROTOCOL
;
1337 * All children of format nodes (except for COW children) and all
1338 * metadata children in general should never be format-probed.
1339 * Force-set BDRV_O_PROTOCOL then.
1341 if ((parent_is_format
&& !(role
& BDRV_CHILD_COW
)) ||
1342 (role
& BDRV_CHILD_METADATA
))
1344 flags
|= BDRV_O_PROTOCOL
;
1348 * If the cache mode isn't explicitly set, inherit direct and no-flush from
1351 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_DIRECT
);
1352 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_NO_FLUSH
);
1353 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_FORCE_SHARE
);
1355 if (role
& BDRV_CHILD_COW
) {
1356 /* backing files are opened read-only by default */
1357 qdict_set_default_str(child_options
, BDRV_OPT_READ_ONLY
, "on");
1358 qdict_set_default_str(child_options
, BDRV_OPT_AUTO_READ_ONLY
, "off");
1360 /* Inherit the read-only option from the parent if it's not set */
1361 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1362 qdict_copy_default(child_options
, parent_options
,
1363 BDRV_OPT_AUTO_READ_ONLY
);
1367 * bdrv_co_pdiscard() respects unmap policy for the parent, so we
1368 * can default to enable it on lower layers regardless of the
1371 qdict_set_default_str(child_options
, BDRV_OPT_DISCARD
, "unmap");
1373 /* Clear flags that only apply to the top layer */
1374 flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_COPY_ON_READ
);
1376 if (role
& BDRV_CHILD_METADATA
) {
1377 flags
&= ~BDRV_O_NO_IO
;
1379 if (role
& BDRV_CHILD_COW
) {
1380 flags
&= ~BDRV_O_TEMPORARY
;
1383 *child_flags
= flags
;
1386 static void bdrv_child_cb_attach(BdrvChild
*child
)
1388 BlockDriverState
*bs
= child
->opaque
;
1390 QLIST_INSERT_HEAD(&bs
->children
, child
, next
);
1392 if (child
->role
& BDRV_CHILD_COW
) {
1393 bdrv_backing_attach(child
);
1396 bdrv_apply_subtree_drain(child
, bs
);
1399 static void bdrv_child_cb_detach(BdrvChild
*child
)
1401 BlockDriverState
*bs
= child
->opaque
;
1403 if (child
->role
& BDRV_CHILD_COW
) {
1404 bdrv_backing_detach(child
);
1407 bdrv_unapply_subtree_drain(child
, bs
);
1409 QLIST_REMOVE(child
, next
);
1412 static int bdrv_child_cb_update_filename(BdrvChild
*c
, BlockDriverState
*base
,
1413 const char *filename
, Error
**errp
)
1415 if (c
->role
& BDRV_CHILD_COW
) {
1416 return bdrv_backing_update_filename(c
, base
, filename
, errp
);
1421 AioContext
*child_of_bds_get_parent_aio_context(BdrvChild
*c
)
1423 BlockDriverState
*bs
= c
->opaque
;
1425 return bdrv_get_aio_context(bs
);
1428 const BdrvChildClass child_of_bds
= {
1429 .parent_is_bds
= true,
1430 .get_parent_desc
= bdrv_child_get_parent_desc
,
1431 .inherit_options
= bdrv_inherited_options
,
1432 .drained_begin
= bdrv_child_cb_drained_begin
,
1433 .drained_poll
= bdrv_child_cb_drained_poll
,
1434 .drained_end
= bdrv_child_cb_drained_end
,
1435 .attach
= bdrv_child_cb_attach
,
1436 .detach
= bdrv_child_cb_detach
,
1437 .inactivate
= bdrv_child_cb_inactivate
,
1438 .can_set_aio_ctx
= bdrv_child_cb_can_set_aio_ctx
,
1439 .set_aio_ctx
= bdrv_child_cb_set_aio_ctx
,
1440 .update_filename
= bdrv_child_cb_update_filename
,
1441 .get_parent_aio_context
= child_of_bds_get_parent_aio_context
,
1444 AioContext
*bdrv_child_get_parent_aio_context(BdrvChild
*c
)
1446 return c
->klass
->get_parent_aio_context(c
);
1449 static int bdrv_open_flags(BlockDriverState
*bs
, int flags
)
1451 int open_flags
= flags
;
1454 * Clear flags that are internal to the block layer before opening the
1457 open_flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_PROTOCOL
);
1462 static void update_flags_from_options(int *flags
, QemuOpts
*opts
)
1464 *flags
&= ~(BDRV_O_CACHE_MASK
| BDRV_O_RDWR
| BDRV_O_AUTO_RDONLY
);
1466 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_NO_FLUSH
, false)) {
1467 *flags
|= BDRV_O_NO_FLUSH
;
1470 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_DIRECT
, false)) {
1471 *flags
|= BDRV_O_NOCACHE
;
1474 if (!qemu_opt_get_bool_del(opts
, BDRV_OPT_READ_ONLY
, false)) {
1475 *flags
|= BDRV_O_RDWR
;
1478 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_AUTO_READ_ONLY
, false)) {
1479 *flags
|= BDRV_O_AUTO_RDONLY
;
1483 static void update_options_from_flags(QDict
*options
, int flags
)
1485 if (!qdict_haskey(options
, BDRV_OPT_CACHE_DIRECT
)) {
1486 qdict_put_bool(options
, BDRV_OPT_CACHE_DIRECT
, flags
& BDRV_O_NOCACHE
);
1488 if (!qdict_haskey(options
, BDRV_OPT_CACHE_NO_FLUSH
)) {
1489 qdict_put_bool(options
, BDRV_OPT_CACHE_NO_FLUSH
,
1490 flags
& BDRV_O_NO_FLUSH
);
1492 if (!qdict_haskey(options
, BDRV_OPT_READ_ONLY
)) {
1493 qdict_put_bool(options
, BDRV_OPT_READ_ONLY
, !(flags
& BDRV_O_RDWR
));
1495 if (!qdict_haskey(options
, BDRV_OPT_AUTO_READ_ONLY
)) {
1496 qdict_put_bool(options
, BDRV_OPT_AUTO_READ_ONLY
,
1497 flags
& BDRV_O_AUTO_RDONLY
);
1501 static void bdrv_assign_node_name(BlockDriverState
*bs
,
1502 const char *node_name
,
1505 char *gen_node_name
= NULL
;
1508 node_name
= gen_node_name
= id_generate(ID_BLOCK
);
1509 } else if (!id_wellformed(node_name
)) {
1511 * Check for empty string or invalid characters, but not if it is
1512 * generated (generated names use characters not available to the user)
1514 error_setg(errp
, "Invalid node-name: '%s'", node_name
);
1518 /* takes care of avoiding namespaces collisions */
1519 if (blk_by_name(node_name
)) {
1520 error_setg(errp
, "node-name=%s is conflicting with a device id",
1525 /* takes care of avoiding duplicates node names */
1526 if (bdrv_find_node(node_name
)) {
1527 error_setg(errp
, "Duplicate nodes with node-name='%s'", node_name
);
1531 /* Make sure that the node name isn't truncated */
1532 if (strlen(node_name
) >= sizeof(bs
->node_name
)) {
1533 error_setg(errp
, "Node name too long");
1537 /* copy node name into the bs and insert it into the graph list */
1538 pstrcpy(bs
->node_name
, sizeof(bs
->node_name
), node_name
);
1539 QTAILQ_INSERT_TAIL(&graph_bdrv_states
, bs
, node_list
);
1541 g_free(gen_node_name
);
1544 static int bdrv_open_driver(BlockDriverState
*bs
, BlockDriver
*drv
,
1545 const char *node_name
, QDict
*options
,
1546 int open_flags
, Error
**errp
)
1548 Error
*local_err
= NULL
;
1551 bdrv_assign_node_name(bs
, node_name
, &local_err
);
1553 error_propagate(errp
, local_err
);
1558 bs
->opaque
= g_malloc0(drv
->instance_size
);
1560 if (drv
->bdrv_file_open
) {
1561 assert(!drv
->bdrv_needs_filename
|| bs
->filename
[0]);
1562 ret
= drv
->bdrv_file_open(bs
, options
, open_flags
, &local_err
);
1563 } else if (drv
->bdrv_open
) {
1564 ret
= drv
->bdrv_open(bs
, options
, open_flags
, &local_err
);
1571 error_propagate(errp
, local_err
);
1572 } else if (bs
->filename
[0]) {
1573 error_setg_errno(errp
, -ret
, "Could not open '%s'", bs
->filename
);
1575 error_setg_errno(errp
, -ret
, "Could not open image");
1580 ret
= refresh_total_sectors(bs
, bs
->total_sectors
);
1582 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
1586 bdrv_refresh_limits(bs
, NULL
, &local_err
);
1588 error_propagate(errp
, local_err
);
1592 assert(bdrv_opt_mem_align(bs
) != 0);
1593 assert(bdrv_min_mem_align(bs
) != 0);
1594 assert(is_power_of_2(bs
->bl
.request_alignment
));
1596 for (i
= 0; i
< bs
->quiesce_counter
; i
++) {
1597 if (drv
->bdrv_co_drain_begin
) {
1598 drv
->bdrv_co_drain_begin(bs
);
1605 if (bs
->file
!= NULL
) {
1606 bdrv_unref_child(bs
, bs
->file
);
1615 * Create and open a block node.
1617 * @options is a QDict of options to pass to the block drivers, or NULL for an
1618 * empty set of options. The reference to the QDict belongs to the block layer
1619 * after the call (even on failure), so if the caller intends to reuse the
1620 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
1622 BlockDriverState
*bdrv_new_open_driver_opts(BlockDriver
*drv
,
1623 const char *node_name
,
1624 QDict
*options
, int flags
,
1627 BlockDriverState
*bs
;
1631 bs
->open_flags
= flags
;
1632 bs
->options
= options
?: qdict_new();
1633 bs
->explicit_options
= qdict_clone_shallow(bs
->options
);
1636 update_options_from_flags(bs
->options
, flags
);
1638 ret
= bdrv_open_driver(bs
, drv
, node_name
, bs
->options
, flags
, errp
);
1640 qobject_unref(bs
->explicit_options
);
1641 bs
->explicit_options
= NULL
;
1642 qobject_unref(bs
->options
);
1651 /* Create and open a block node. */
1652 BlockDriverState
*bdrv_new_open_driver(BlockDriver
*drv
, const char *node_name
,
1653 int flags
, Error
**errp
)
1655 return bdrv_new_open_driver_opts(drv
, node_name
, NULL
, flags
, errp
);
1658 QemuOptsList bdrv_runtime_opts
= {
1659 .name
= "bdrv_common",
1660 .head
= QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts
.head
),
1663 .name
= "node-name",
1664 .type
= QEMU_OPT_STRING
,
1665 .help
= "Node name of the block device node",
1669 .type
= QEMU_OPT_STRING
,
1670 .help
= "Block driver to use for the node",
1673 .name
= BDRV_OPT_CACHE_DIRECT
,
1674 .type
= QEMU_OPT_BOOL
,
1675 .help
= "Bypass software writeback cache on the host",
1678 .name
= BDRV_OPT_CACHE_NO_FLUSH
,
1679 .type
= QEMU_OPT_BOOL
,
1680 .help
= "Ignore flush requests",
1683 .name
= BDRV_OPT_READ_ONLY
,
1684 .type
= QEMU_OPT_BOOL
,
1685 .help
= "Node is opened in read-only mode",
1688 .name
= BDRV_OPT_AUTO_READ_ONLY
,
1689 .type
= QEMU_OPT_BOOL
,
1690 .help
= "Node can become read-only if opening read-write fails",
1693 .name
= "detect-zeroes",
1694 .type
= QEMU_OPT_STRING
,
1695 .help
= "try to optimize zero writes (off, on, unmap)",
1698 .name
= BDRV_OPT_DISCARD
,
1699 .type
= QEMU_OPT_STRING
,
1700 .help
= "discard operation (ignore/off, unmap/on)",
1703 .name
= BDRV_OPT_FORCE_SHARE
,
1704 .type
= QEMU_OPT_BOOL
,
1705 .help
= "always accept other writers (default: off)",
1707 { /* end of list */ }
1711 QemuOptsList bdrv_create_opts_simple
= {
1712 .name
= "simple-create-opts",
1713 .head
= QTAILQ_HEAD_INITIALIZER(bdrv_create_opts_simple
.head
),
1716 .name
= BLOCK_OPT_SIZE
,
1717 .type
= QEMU_OPT_SIZE
,
1718 .help
= "Virtual disk size"
1721 .name
= BLOCK_OPT_PREALLOC
,
1722 .type
= QEMU_OPT_STRING
,
1723 .help
= "Preallocation mode (allowed values: off)"
1725 { /* end of list */ }
1730 * Common part for opening disk images and files
1732 * Removes all processed options from *options.
1734 static int bdrv_open_common(BlockDriverState
*bs
, BlockBackend
*file
,
1735 QDict
*options
, Error
**errp
)
1737 int ret
, open_flags
;
1738 const char *filename
;
1739 const char *driver_name
= NULL
;
1740 const char *node_name
= NULL
;
1741 const char *discard
;
1744 Error
*local_err
= NULL
;
1747 assert(bs
->file
== NULL
);
1748 assert(options
!= NULL
&& bs
->options
!= options
);
1750 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
1751 if (!qemu_opts_absorb_qdict(opts
, options
, errp
)) {
1756 update_flags_from_options(&bs
->open_flags
, opts
);
1758 driver_name
= qemu_opt_get(opts
, "driver");
1759 drv
= bdrv_find_format(driver_name
);
1760 assert(drv
!= NULL
);
1762 bs
->force_share
= qemu_opt_get_bool(opts
, BDRV_OPT_FORCE_SHARE
, false);
1764 if (bs
->force_share
&& (bs
->open_flags
& BDRV_O_RDWR
)) {
1766 BDRV_OPT_FORCE_SHARE
1767 "=on can only be used with read-only images");
1773 bdrv_refresh_filename(blk_bs(file
));
1774 filename
= blk_bs(file
)->filename
;
1777 * Caution: while qdict_get_try_str() is fine, getting
1778 * non-string types would require more care. When @options
1779 * come from -blockdev or blockdev_add, its members are typed
1780 * according to the QAPI schema, but when they come from
1781 * -drive, they're all QString.
1783 filename
= qdict_get_try_str(options
, "filename");
1786 if (drv
->bdrv_needs_filename
&& (!filename
|| !filename
[0])) {
1787 error_setg(errp
, "The '%s' block driver requires a file name",
1793 trace_bdrv_open_common(bs
, filename
?: "", bs
->open_flags
,
1796 ro
= bdrv_is_read_only(bs
);
1798 if (use_bdrv_whitelist
&& !bdrv_is_whitelisted(drv
, ro
)) {
1799 if (!ro
&& bdrv_is_whitelisted(drv
, true)) {
1800 ret
= bdrv_apply_auto_read_only(bs
, NULL
, NULL
);
1806 !ro
&& bdrv_is_whitelisted(drv
, true)
1807 ? "Driver '%s' can only be used for read-only devices"
1808 : "Driver '%s' is not whitelisted",
1814 /* bdrv_new() and bdrv_close() make it so */
1815 assert(qatomic_read(&bs
->copy_on_read
) == 0);
1817 if (bs
->open_flags
& BDRV_O_COPY_ON_READ
) {
1819 bdrv_enable_copy_on_read(bs
);
1821 error_setg(errp
, "Can't use copy-on-read on read-only device");
1827 discard
= qemu_opt_get(opts
, BDRV_OPT_DISCARD
);
1828 if (discard
!= NULL
) {
1829 if (bdrv_parse_discard_flags(discard
, &bs
->open_flags
) != 0) {
1830 error_setg(errp
, "Invalid discard option");
1837 bdrv_parse_detect_zeroes(opts
, bs
->open_flags
, &local_err
);
1839 error_propagate(errp
, local_err
);
1844 if (filename
!= NULL
) {
1845 pstrcpy(bs
->filename
, sizeof(bs
->filename
), filename
);
1847 bs
->filename
[0] = '\0';
1849 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
), bs
->filename
);
1851 /* Open the image, either directly or using a protocol */
1852 open_flags
= bdrv_open_flags(bs
, bs
->open_flags
);
1853 node_name
= qemu_opt_get(opts
, "node-name");
1855 assert(!drv
->bdrv_file_open
|| file
== NULL
);
1856 ret
= bdrv_open_driver(bs
, drv
, node_name
, options
, open_flags
, errp
);
1861 qemu_opts_del(opts
);
1865 qemu_opts_del(opts
);
1869 static QDict
*parse_json_filename(const char *filename
, Error
**errp
)
1871 QObject
*options_obj
;
1875 ret
= strstart(filename
, "json:", &filename
);
1878 options_obj
= qobject_from_json(filename
, errp
);
1880 error_prepend(errp
, "Could not parse the JSON options: ");
1884 options
= qobject_to(QDict
, options_obj
);
1886 qobject_unref(options_obj
);
1887 error_setg(errp
, "Invalid JSON object given");
1891 qdict_flatten(options
);
1896 static void parse_json_protocol(QDict
*options
, const char **pfilename
,
1899 QDict
*json_options
;
1900 Error
*local_err
= NULL
;
1902 /* Parse json: pseudo-protocol */
1903 if (!*pfilename
|| !g_str_has_prefix(*pfilename
, "json:")) {
1907 json_options
= parse_json_filename(*pfilename
, &local_err
);
1909 error_propagate(errp
, local_err
);
1913 /* Options given in the filename have lower priority than options
1914 * specified directly */
1915 qdict_join(options
, json_options
, false);
1916 qobject_unref(json_options
);
1921 * Fills in default options for opening images and converts the legacy
1922 * filename/flags pair to option QDict entries.
1923 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1924 * block driver has been specified explicitly.
1926 static int bdrv_fill_options(QDict
**options
, const char *filename
,
1927 int *flags
, Error
**errp
)
1929 const char *drvname
;
1930 bool protocol
= *flags
& BDRV_O_PROTOCOL
;
1931 bool parse_filename
= false;
1932 BlockDriver
*drv
= NULL
;
1933 Error
*local_err
= NULL
;
1936 * Caution: while qdict_get_try_str() is fine, getting non-string
1937 * types would require more care. When @options come from
1938 * -blockdev or blockdev_add, its members are typed according to
1939 * the QAPI schema, but when they come from -drive, they're all
1942 drvname
= qdict_get_try_str(*options
, "driver");
1944 drv
= bdrv_find_format(drvname
);
1946 error_setg(errp
, "Unknown driver '%s'", drvname
);
1949 /* If the user has explicitly specified the driver, this choice should
1950 * override the BDRV_O_PROTOCOL flag */
1951 protocol
= drv
->bdrv_file_open
;
1955 *flags
|= BDRV_O_PROTOCOL
;
1957 *flags
&= ~BDRV_O_PROTOCOL
;
1960 /* Translate cache options from flags into options */
1961 update_options_from_flags(*options
, *flags
);
1963 /* Fetch the file name from the options QDict if necessary */
1964 if (protocol
&& filename
) {
1965 if (!qdict_haskey(*options
, "filename")) {
1966 qdict_put_str(*options
, "filename", filename
);
1967 parse_filename
= true;
1969 error_setg(errp
, "Can't specify 'file' and 'filename' options at "
1975 /* Find the right block driver */
1976 /* See cautionary note on accessing @options above */
1977 filename
= qdict_get_try_str(*options
, "filename");
1979 if (!drvname
&& protocol
) {
1981 drv
= bdrv_find_protocol(filename
, parse_filename
, errp
);
1986 drvname
= drv
->format_name
;
1987 qdict_put_str(*options
, "driver", drvname
);
1989 error_setg(errp
, "Must specify either driver or file");
1994 assert(drv
|| !protocol
);
1996 /* Driver-specific filename parsing */
1997 if (drv
&& drv
->bdrv_parse_filename
&& parse_filename
) {
1998 drv
->bdrv_parse_filename(filename
, *options
, &local_err
);
2000 error_propagate(errp
, local_err
);
2004 if (!drv
->bdrv_needs_filename
) {
2005 qdict_del(*options
, "filename");
2012 typedef struct BlockReopenQueueEntry
{
2015 BDRVReopenState state
;
2016 QTAILQ_ENTRY(BlockReopenQueueEntry
) entry
;
2017 } BlockReopenQueueEntry
;
2020 * Return the flags that @bs will have after the reopens in @q have
2021 * successfully completed. If @q is NULL (or @bs is not contained in @q),
2022 * return the current flags.
2024 static int bdrv_reopen_get_flags(BlockReopenQueue
*q
, BlockDriverState
*bs
)
2026 BlockReopenQueueEntry
*entry
;
2029 QTAILQ_FOREACH(entry
, q
, entry
) {
2030 if (entry
->state
.bs
== bs
) {
2031 return entry
->state
.flags
;
2036 return bs
->open_flags
;
2039 /* Returns whether the image file can be written to after the reopen queue @q
2040 * has been successfully applied, or right now if @q is NULL. */
2041 static bool bdrv_is_writable_after_reopen(BlockDriverState
*bs
,
2042 BlockReopenQueue
*q
)
2044 int flags
= bdrv_reopen_get_flags(q
, bs
);
2046 return (flags
& (BDRV_O_RDWR
| BDRV_O_INACTIVE
)) == BDRV_O_RDWR
;
2050 * Return whether the BDS can be written to. This is not necessarily
2051 * the same as !bdrv_is_read_only(bs), as inactivated images may not
2052 * be written to but do not count as read-only images.
2054 bool bdrv_is_writable(BlockDriverState
*bs
)
2056 return bdrv_is_writable_after_reopen(bs
, NULL
);
2059 static char *bdrv_child_user_desc(BdrvChild
*c
)
2061 return c
->klass
->get_parent_desc(c
);
2065 * Check that @a allows everything that @b needs. @a and @b must reference same
2068 static bool bdrv_a_allow_b(BdrvChild
*a
, BdrvChild
*b
, Error
**errp
)
2070 const char *child_bs_name
;
2071 g_autofree
char *a_user
= NULL
;
2072 g_autofree
char *b_user
= NULL
;
2073 g_autofree
char *perms
= NULL
;
2076 assert(a
->bs
== b
->bs
);
2078 if ((b
->perm
& a
->shared_perm
) == b
->perm
) {
2082 child_bs_name
= bdrv_get_node_name(b
->bs
);
2083 a_user
= bdrv_child_user_desc(a
);
2084 b_user
= bdrv_child_user_desc(b
);
2085 perms
= bdrv_perm_names(b
->perm
& ~a
->shared_perm
);
2087 error_setg(errp
, "Permission conflict on node '%s': permissions '%s' are "
2088 "both required by %s (uses node '%s' as '%s' child) and "
2089 "unshared by %s (uses node '%s' as '%s' child).",
2090 child_bs_name
, perms
,
2091 b_user
, child_bs_name
, b
->name
,
2092 a_user
, child_bs_name
, a
->name
);
2097 static bool bdrv_parent_perms_conflict(BlockDriverState
*bs
, Error
**errp
)
2102 * During the loop we'll look at each pair twice. That's correct because
2103 * bdrv_a_allow_b() is asymmetric and we should check each pair in both
2106 QLIST_FOREACH(a
, &bs
->parents
, next_parent
) {
2107 QLIST_FOREACH(b
, &bs
->parents
, next_parent
) {
2112 if (!bdrv_a_allow_b(a
, b
, errp
)) {
2121 static void bdrv_child_perm(BlockDriverState
*bs
, BlockDriverState
*child_bs
,
2122 BdrvChild
*c
, BdrvChildRole role
,
2123 BlockReopenQueue
*reopen_queue
,
2124 uint64_t parent_perm
, uint64_t parent_shared
,
2125 uint64_t *nperm
, uint64_t *nshared
)
2127 assert(bs
->drv
&& bs
->drv
->bdrv_child_perm
);
2128 bs
->drv
->bdrv_child_perm(bs
, c
, role
, reopen_queue
,
2129 parent_perm
, parent_shared
,
2131 /* TODO Take force_share from reopen_queue */
2132 if (child_bs
&& child_bs
->force_share
) {
2133 *nshared
= BLK_PERM_ALL
;
2138 * Adds the whole subtree of @bs (including @bs itself) to the @list (except for
2139 * nodes that are already in the @list, of course) so that final list is
2140 * topologically sorted. Return the result (GSList @list object is updated, so
2141 * don't use old reference after function call).
2143 * On function start @list must be already topologically sorted and for any node
2144 * in the @list the whole subtree of the node must be in the @list as well. The
2145 * simplest way to satisfy this criteria: use only result of
2146 * bdrv_topological_dfs() or NULL as @list parameter.
2148 static GSList
*bdrv_topological_dfs(GSList
*list
, GHashTable
*found
,
2149 BlockDriverState
*bs
)
2152 g_autoptr(GHashTable
) local_found
= NULL
;
2156 found
= local_found
= g_hash_table_new(NULL
, NULL
);
2159 if (g_hash_table_contains(found
, bs
)) {
2162 g_hash_table_add(found
, bs
);
2164 QLIST_FOREACH(child
, &bs
->children
, next
) {
2165 list
= bdrv_topological_dfs(list
, found
, child
->bs
);
2168 return g_slist_prepend(list
, bs
);
2171 typedef struct BdrvChildSetPermState
{
2174 uint64_t old_shared_perm
;
2175 } BdrvChildSetPermState
;
2177 static void bdrv_child_set_perm_abort(void *opaque
)
2179 BdrvChildSetPermState
*s
= opaque
;
2181 s
->child
->perm
= s
->old_perm
;
2182 s
->child
->shared_perm
= s
->old_shared_perm
;
2185 static TransactionActionDrv bdrv_child_set_pem_drv
= {
2186 .abort
= bdrv_child_set_perm_abort
,
2190 static void bdrv_child_set_perm(BdrvChild
*c
, uint64_t perm
,
2191 uint64_t shared
, Transaction
*tran
)
2193 BdrvChildSetPermState
*s
= g_new(BdrvChildSetPermState
, 1);
2195 *s
= (BdrvChildSetPermState
) {
2197 .old_perm
= c
->perm
,
2198 .old_shared_perm
= c
->shared_perm
,
2202 c
->shared_perm
= shared
;
2204 tran_add(tran
, &bdrv_child_set_pem_drv
, s
);
2207 static void bdrv_drv_set_perm_commit(void *opaque
)
2209 BlockDriverState
*bs
= opaque
;
2210 uint64_t cumulative_perms
, cumulative_shared_perms
;
2212 if (bs
->drv
->bdrv_set_perm
) {
2213 bdrv_get_cumulative_perm(bs
, &cumulative_perms
,
2214 &cumulative_shared_perms
);
2215 bs
->drv
->bdrv_set_perm(bs
, cumulative_perms
, cumulative_shared_perms
);
2219 static void bdrv_drv_set_perm_abort(void *opaque
)
2221 BlockDriverState
*bs
= opaque
;
2223 if (bs
->drv
->bdrv_abort_perm_update
) {
2224 bs
->drv
->bdrv_abort_perm_update(bs
);
2228 TransactionActionDrv bdrv_drv_set_perm_drv
= {
2229 .abort
= bdrv_drv_set_perm_abort
,
2230 .commit
= bdrv_drv_set_perm_commit
,
2233 static int bdrv_drv_set_perm(BlockDriverState
*bs
, uint64_t perm
,
2234 uint64_t shared_perm
, Transaction
*tran
,
2241 if (bs
->drv
->bdrv_check_perm
) {
2242 int ret
= bs
->drv
->bdrv_check_perm(bs
, perm
, shared_perm
, errp
);
2249 tran_add(tran
, &bdrv_drv_set_perm_drv
, bs
);
2255 typedef struct BdrvReplaceChildState
{
2257 BlockDriverState
*old_bs
;
2258 } BdrvReplaceChildState
;
2260 static void bdrv_replace_child_commit(void *opaque
)
2262 BdrvReplaceChildState
*s
= opaque
;
2264 bdrv_unref(s
->old_bs
);
2267 static void bdrv_replace_child_abort(void *opaque
)
2269 BdrvReplaceChildState
*s
= opaque
;
2270 BlockDriverState
*new_bs
= s
->child
->bs
;
2272 /* old_bs reference is transparently moved from @s to @s->child */
2273 bdrv_replace_child_noperm(&s
->child
, s
->old_bs
);
2277 static TransactionActionDrv bdrv_replace_child_drv
= {
2278 .commit
= bdrv_replace_child_commit
,
2279 .abort
= bdrv_replace_child_abort
,
2284 * bdrv_replace_child_tran
2286 * Note: real unref of old_bs is done only on commit.
2288 * The function doesn't update permissions, caller is responsible for this.
2290 static void bdrv_replace_child_tran(BdrvChild
*child
, BlockDriverState
*new_bs
,
2293 BdrvReplaceChildState
*s
= g_new(BdrvReplaceChildState
, 1);
2294 *s
= (BdrvReplaceChildState
) {
2296 .old_bs
= child
->bs
,
2298 tran_add(tran
, &bdrv_replace_child_drv
, s
);
2303 bdrv_replace_child_noperm(&child
, new_bs
);
2304 /* old_bs reference is transparently moved from @child to @s */
2308 * Refresh permissions in @bs subtree. The function is intended to be called
2309 * after some graph modification that was done without permission update.
2311 static int bdrv_node_refresh_perm(BlockDriverState
*bs
, BlockReopenQueue
*q
,
2312 Transaction
*tran
, Error
**errp
)
2314 BlockDriver
*drv
= bs
->drv
;
2317 uint64_t cumulative_perms
, cumulative_shared_perms
;
2319 bdrv_get_cumulative_perm(bs
, &cumulative_perms
, &cumulative_shared_perms
);
2321 /* Write permissions never work with read-only images */
2322 if ((cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) &&
2323 !bdrv_is_writable_after_reopen(bs
, q
))
2325 if (!bdrv_is_writable_after_reopen(bs
, NULL
)) {
2326 error_setg(errp
, "Block node is read-only");
2328 error_setg(errp
, "Read-only block node '%s' cannot support "
2329 "read-write users", bdrv_get_node_name(bs
));
2336 * Unaligned requests will automatically be aligned to bl.request_alignment
2337 * and without RESIZE we can't extend requests to write to space beyond the
2338 * end of the image, so it's required that the image size is aligned.
2340 if ((cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) &&
2341 !(cumulative_perms
& BLK_PERM_RESIZE
))
2343 if ((bs
->total_sectors
* BDRV_SECTOR_SIZE
) % bs
->bl
.request_alignment
) {
2344 error_setg(errp
, "Cannot get 'write' permission without 'resize': "
2345 "Image size is not a multiple of request "
2351 /* Check this node */
2356 ret
= bdrv_drv_set_perm(bs
, cumulative_perms
, cumulative_shared_perms
, tran
,
2362 /* Drivers that never have children can omit .bdrv_child_perm() */
2363 if (!drv
->bdrv_child_perm
) {
2364 assert(QLIST_EMPTY(&bs
->children
));
2368 /* Check all children */
2369 QLIST_FOREACH(c
, &bs
->children
, next
) {
2370 uint64_t cur_perm
, cur_shared
;
2372 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, q
,
2373 cumulative_perms
, cumulative_shared_perms
,
2374 &cur_perm
, &cur_shared
);
2375 bdrv_child_set_perm(c
, cur_perm
, cur_shared
, tran
);
2381 static int bdrv_list_refresh_perms(GSList
*list
, BlockReopenQueue
*q
,
2382 Transaction
*tran
, Error
**errp
)
2385 BlockDriverState
*bs
;
2387 for ( ; list
; list
= list
->next
) {
2390 if (bdrv_parent_perms_conflict(bs
, errp
)) {
2394 ret
= bdrv_node_refresh_perm(bs
, q
, tran
, errp
);
2403 void bdrv_get_cumulative_perm(BlockDriverState
*bs
, uint64_t *perm
,
2404 uint64_t *shared_perm
)
2407 uint64_t cumulative_perms
= 0;
2408 uint64_t cumulative_shared_perms
= BLK_PERM_ALL
;
2410 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
2411 cumulative_perms
|= c
->perm
;
2412 cumulative_shared_perms
&= c
->shared_perm
;
2415 *perm
= cumulative_perms
;
2416 *shared_perm
= cumulative_shared_perms
;
2419 char *bdrv_perm_names(uint64_t perm
)
2425 { BLK_PERM_CONSISTENT_READ
, "consistent read" },
2426 { BLK_PERM_WRITE
, "write" },
2427 { BLK_PERM_WRITE_UNCHANGED
, "write unchanged" },
2428 { BLK_PERM_RESIZE
, "resize" },
2429 { BLK_PERM_GRAPH_MOD
, "change children" },
2433 GString
*result
= g_string_sized_new(30);
2434 struct perm_name
*p
;
2436 for (p
= permissions
; p
->name
; p
++) {
2437 if (perm
& p
->perm
) {
2438 if (result
->len
> 0) {
2439 g_string_append(result
, ", ");
2441 g_string_append(result
, p
->name
);
2445 return g_string_free(result
, FALSE
);
2449 static int bdrv_refresh_perms(BlockDriverState
*bs
, Error
**errp
)
2452 Transaction
*tran
= tran_new();
2453 g_autoptr(GSList
) list
= bdrv_topological_dfs(NULL
, NULL
, bs
);
2455 ret
= bdrv_list_refresh_perms(list
, NULL
, tran
, errp
);
2456 tran_finalize(tran
, ret
);
2461 int bdrv_child_try_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
,
2464 Error
*local_err
= NULL
;
2465 Transaction
*tran
= tran_new();
2468 bdrv_child_set_perm(c
, perm
, shared
, tran
);
2470 ret
= bdrv_refresh_perms(c
->bs
, &local_err
);
2472 tran_finalize(tran
, ret
);
2475 if ((perm
& ~c
->perm
) || (c
->shared_perm
& ~shared
)) {
2476 /* tighten permissions */
2477 error_propagate(errp
, local_err
);
2480 * Our caller may intend to only loosen restrictions and
2481 * does not expect this function to fail. Errors are not
2482 * fatal in such a case, so we can just hide them from our
2485 error_free(local_err
);
2493 int bdrv_child_refresh_perms(BlockDriverState
*bs
, BdrvChild
*c
, Error
**errp
)
2495 uint64_t parent_perms
, parent_shared
;
2496 uint64_t perms
, shared
;
2498 bdrv_get_cumulative_perm(bs
, &parent_perms
, &parent_shared
);
2499 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, NULL
,
2500 parent_perms
, parent_shared
, &perms
, &shared
);
2502 return bdrv_child_try_set_perm(c
, perms
, shared
, errp
);
2506 * Default implementation for .bdrv_child_perm() for block filters:
2507 * Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED, and RESIZE to the
2510 static void bdrv_filter_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2512 BlockReopenQueue
*reopen_queue
,
2513 uint64_t perm
, uint64_t shared
,
2514 uint64_t *nperm
, uint64_t *nshared
)
2516 *nperm
= perm
& DEFAULT_PERM_PASSTHROUGH
;
2517 *nshared
= (shared
& DEFAULT_PERM_PASSTHROUGH
) | DEFAULT_PERM_UNCHANGED
;
2520 static void bdrv_default_perms_for_cow(BlockDriverState
*bs
, BdrvChild
*c
,
2522 BlockReopenQueue
*reopen_queue
,
2523 uint64_t perm
, uint64_t shared
,
2524 uint64_t *nperm
, uint64_t *nshared
)
2526 assert(role
& BDRV_CHILD_COW
);
2529 * We want consistent read from backing files if the parent needs it.
2530 * No other operations are performed on backing files.
2532 perm
&= BLK_PERM_CONSISTENT_READ
;
2535 * If the parent can deal with changing data, we're okay with a
2536 * writable and resizable backing file.
2537 * TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too?
2539 if (shared
& BLK_PERM_WRITE
) {
2540 shared
= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2545 shared
|= BLK_PERM_CONSISTENT_READ
| BLK_PERM_GRAPH_MOD
|
2546 BLK_PERM_WRITE_UNCHANGED
;
2548 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
2549 shared
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2556 static void bdrv_default_perms_for_storage(BlockDriverState
*bs
, BdrvChild
*c
,
2558 BlockReopenQueue
*reopen_queue
,
2559 uint64_t perm
, uint64_t shared
,
2560 uint64_t *nperm
, uint64_t *nshared
)
2564 assert(role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_DATA
));
2566 flags
= bdrv_reopen_get_flags(reopen_queue
, bs
);
2569 * Apart from the modifications below, the same permissions are
2570 * forwarded and left alone as for filters
2572 bdrv_filter_default_perms(bs
, c
, role
, reopen_queue
,
2573 perm
, shared
, &perm
, &shared
);
2575 if (role
& BDRV_CHILD_METADATA
) {
2576 /* Format drivers may touch metadata even if the guest doesn't write */
2577 if (bdrv_is_writable_after_reopen(bs
, reopen_queue
)) {
2578 perm
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2582 * bs->file always needs to be consistent because of the
2583 * metadata. We can never allow other users to resize or write
2586 if (!(flags
& BDRV_O_NO_IO
)) {
2587 perm
|= BLK_PERM_CONSISTENT_READ
;
2589 shared
&= ~(BLK_PERM_WRITE
| BLK_PERM_RESIZE
);
2592 if (role
& BDRV_CHILD_DATA
) {
2594 * Technically, everything in this block is a subset of the
2595 * BDRV_CHILD_METADATA path taken above, and so this could
2596 * be an "else if" branch. However, that is not obvious, and
2597 * this function is not performance critical, therefore we let
2598 * this be an independent "if".
2602 * We cannot allow other users to resize the file because the
2603 * format driver might have some assumptions about the size
2604 * (e.g. because it is stored in metadata, or because the file
2605 * is split into fixed-size data files).
2607 shared
&= ~BLK_PERM_RESIZE
;
2610 * WRITE_UNCHANGED often cannot be performed as such on the
2611 * data file. For example, the qcow2 driver may still need to
2612 * write copied clusters on copy-on-read.
2614 if (perm
& BLK_PERM_WRITE_UNCHANGED
) {
2615 perm
|= BLK_PERM_WRITE
;
2619 * If the data file is written to, the format driver may
2620 * expect to be able to resize it by writing beyond the EOF.
2622 if (perm
& BLK_PERM_WRITE
) {
2623 perm
|= BLK_PERM_RESIZE
;
2627 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
2628 shared
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2635 void bdrv_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2636 BdrvChildRole role
, BlockReopenQueue
*reopen_queue
,
2637 uint64_t perm
, uint64_t shared
,
2638 uint64_t *nperm
, uint64_t *nshared
)
2640 if (role
& BDRV_CHILD_FILTERED
) {
2641 assert(!(role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
|
2643 bdrv_filter_default_perms(bs
, c
, role
, reopen_queue
,
2644 perm
, shared
, nperm
, nshared
);
2645 } else if (role
& BDRV_CHILD_COW
) {
2646 assert(!(role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
)));
2647 bdrv_default_perms_for_cow(bs
, c
, role
, reopen_queue
,
2648 perm
, shared
, nperm
, nshared
);
2649 } else if (role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_DATA
)) {
2650 bdrv_default_perms_for_storage(bs
, c
, role
, reopen_queue
,
2651 perm
, shared
, nperm
, nshared
);
2653 g_assert_not_reached();
2657 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm
)
2659 static const uint64_t permissions
[] = {
2660 [BLOCK_PERMISSION_CONSISTENT_READ
] = BLK_PERM_CONSISTENT_READ
,
2661 [BLOCK_PERMISSION_WRITE
] = BLK_PERM_WRITE
,
2662 [BLOCK_PERMISSION_WRITE_UNCHANGED
] = BLK_PERM_WRITE_UNCHANGED
,
2663 [BLOCK_PERMISSION_RESIZE
] = BLK_PERM_RESIZE
,
2664 [BLOCK_PERMISSION_GRAPH_MOD
] = BLK_PERM_GRAPH_MOD
,
2667 QEMU_BUILD_BUG_ON(ARRAY_SIZE(permissions
) != BLOCK_PERMISSION__MAX
);
2668 QEMU_BUILD_BUG_ON(1UL << ARRAY_SIZE(permissions
) != BLK_PERM_ALL
+ 1);
2670 assert(qapi_perm
< BLOCK_PERMISSION__MAX
);
2672 return permissions
[qapi_perm
];
2675 static void bdrv_replace_child_noperm(BdrvChild
**childp
,
2676 BlockDriverState
*new_bs
)
2678 BdrvChild
*child
= *childp
;
2679 BlockDriverState
*old_bs
= child
->bs
;
2680 int new_bs_quiesce_counter
;
2683 assert(!child
->frozen
);
2684 assert(old_bs
!= new_bs
);
2686 if (old_bs
&& new_bs
) {
2687 assert(bdrv_get_aio_context(old_bs
) == bdrv_get_aio_context(new_bs
));
2690 new_bs_quiesce_counter
= (new_bs
? new_bs
->quiesce_counter
: 0);
2691 drain_saldo
= new_bs_quiesce_counter
- child
->parent_quiesce_counter
;
2694 * If the new child node is drained but the old one was not, flush
2695 * all outstanding requests to the old child node.
2697 while (drain_saldo
> 0 && child
->klass
->drained_begin
) {
2698 bdrv_parent_drained_begin_single(child
, true);
2703 /* Detach first so that the recursive drain sections coming from @child
2704 * are already gone and we only end the drain sections that came from
2706 if (child
->klass
->detach
) {
2707 child
->klass
->detach(child
);
2709 QLIST_REMOVE(child
, next_parent
);
2715 QLIST_INSERT_HEAD(&new_bs
->parents
, child
, next_parent
);
2718 * Detaching the old node may have led to the new node's
2719 * quiesce_counter having been decreased. Not a problem, we
2720 * just need to recognize this here and then invoke
2721 * drained_end appropriately more often.
2723 assert(new_bs
->quiesce_counter
<= new_bs_quiesce_counter
);
2724 drain_saldo
+= new_bs
->quiesce_counter
- new_bs_quiesce_counter
;
2726 /* Attach only after starting new drained sections, so that recursive
2727 * drain sections coming from @child don't get an extra .drained_begin
2729 if (child
->klass
->attach
) {
2730 child
->klass
->attach(child
);
2735 * If the old child node was drained but the new one is not, allow
2736 * requests to come in only after the new node has been attached.
2738 while (drain_saldo
< 0 && child
->klass
->drained_end
) {
2739 bdrv_parent_drained_end_single(child
);
2745 * Free the given @child.
2747 * The child must be empty (i.e. `child->bs == NULL`) and it must be
2748 * unused (i.e. not in a children list).
2750 static void bdrv_child_free(BdrvChild
*child
)
2753 assert(!child
->next
.le_prev
); /* not in children list */
2755 g_free(child
->name
);
2759 typedef struct BdrvAttachChildCommonState
{
2761 AioContext
*old_parent_ctx
;
2762 AioContext
*old_child_ctx
;
2763 } BdrvAttachChildCommonState
;
2765 static void bdrv_attach_child_common_abort(void *opaque
)
2767 BdrvAttachChildCommonState
*s
= opaque
;
2768 BdrvChild
*child
= *s
->child
;
2769 BlockDriverState
*bs
= child
->bs
;
2771 bdrv_replace_child_noperm(s
->child
, NULL
);
2773 if (bdrv_get_aio_context(bs
) != s
->old_child_ctx
) {
2774 bdrv_try_set_aio_context(bs
, s
->old_child_ctx
, &error_abort
);
2777 if (bdrv_child_get_parent_aio_context(child
) != s
->old_parent_ctx
) {
2780 /* No need to ignore `child`, because it has been detached already */
2782 child
->klass
->can_set_aio_ctx(child
, s
->old_parent_ctx
, &ignore
,
2784 g_slist_free(ignore
);
2787 child
->klass
->set_aio_ctx(child
, s
->old_parent_ctx
, &ignore
);
2788 g_slist_free(ignore
);
2792 bdrv_child_free(child
);
2796 static TransactionActionDrv bdrv_attach_child_common_drv
= {
2797 .abort
= bdrv_attach_child_common_abort
,
2802 * Common part of attaching bdrv child to bs or to blk or to job
2804 * Resulting new child is returned through @child.
2805 * At start *@child must be NULL.
2806 * @child is saved to a new entry of @tran, so that *@child could be reverted to
2807 * NULL on abort(). So referenced variable must live at least until transaction
2810 * Function doesn't update permissions, caller is responsible for this.
2812 static int bdrv_attach_child_common(BlockDriverState
*child_bs
,
2813 const char *child_name
,
2814 const BdrvChildClass
*child_class
,
2815 BdrvChildRole child_role
,
2816 uint64_t perm
, uint64_t shared_perm
,
2817 void *opaque
, BdrvChild
**child
,
2818 Transaction
*tran
, Error
**errp
)
2820 BdrvChild
*new_child
;
2821 AioContext
*parent_ctx
;
2822 AioContext
*child_ctx
= bdrv_get_aio_context(child_bs
);
2825 assert(*child
== NULL
);
2826 assert(child_class
->get_parent_desc
);
2828 new_child
= g_new(BdrvChild
, 1);
2829 *new_child
= (BdrvChild
) {
2831 .name
= g_strdup(child_name
),
2832 .klass
= child_class
,
2835 .shared_perm
= shared_perm
,
2840 * If the AioContexts don't match, first try to move the subtree of
2841 * child_bs into the AioContext of the new parent. If this doesn't work,
2842 * try moving the parent into the AioContext of child_bs instead.
2844 parent_ctx
= bdrv_child_get_parent_aio_context(new_child
);
2845 if (child_ctx
!= parent_ctx
) {
2846 Error
*local_err
= NULL
;
2847 int ret
= bdrv_try_set_aio_context(child_bs
, parent_ctx
, &local_err
);
2849 if (ret
< 0 && child_class
->can_set_aio_ctx
) {
2850 GSList
*ignore
= g_slist_prepend(NULL
, new_child
);
2851 if (child_class
->can_set_aio_ctx(new_child
, child_ctx
, &ignore
,
2854 error_free(local_err
);
2856 g_slist_free(ignore
);
2857 ignore
= g_slist_prepend(NULL
, new_child
);
2858 child_class
->set_aio_ctx(new_child
, child_ctx
, &ignore
);
2860 g_slist_free(ignore
);
2864 error_propagate(errp
, local_err
);
2865 bdrv_child_free(new_child
);
2871 bdrv_replace_child_noperm(&new_child
, child_bs
);
2875 BdrvAttachChildCommonState
*s
= g_new(BdrvAttachChildCommonState
, 1);
2876 *s
= (BdrvAttachChildCommonState
) {
2878 .old_parent_ctx
= parent_ctx
,
2879 .old_child_ctx
= child_ctx
,
2881 tran_add(tran
, &bdrv_attach_child_common_drv
, s
);
2887 * Variable referenced by @child must live at least until transaction end.
2888 * (see bdrv_attach_child_common() doc for details)
2890 * Function doesn't update permissions, caller is responsible for this.
2892 static int bdrv_attach_child_noperm(BlockDriverState
*parent_bs
,
2893 BlockDriverState
*child_bs
,
2894 const char *child_name
,
2895 const BdrvChildClass
*child_class
,
2896 BdrvChildRole child_role
,
2902 uint64_t perm
, shared_perm
;
2904 assert(parent_bs
->drv
);
2906 if (bdrv_recurse_has_child(child_bs
, parent_bs
)) {
2907 error_setg(errp
, "Making '%s' a %s child of '%s' would create a cycle",
2908 child_bs
->node_name
, child_name
, parent_bs
->node_name
);
2912 bdrv_get_cumulative_perm(parent_bs
, &perm
, &shared_perm
);
2913 bdrv_child_perm(parent_bs
, child_bs
, NULL
, child_role
, NULL
,
2914 perm
, shared_perm
, &perm
, &shared_perm
);
2916 ret
= bdrv_attach_child_common(child_bs
, child_name
, child_class
,
2917 child_role
, perm
, shared_perm
, parent_bs
,
2926 static void bdrv_detach_child(BdrvChild
**childp
)
2928 BlockDriverState
*old_bs
= (*childp
)->bs
;
2930 bdrv_replace_child_noperm(childp
, NULL
);
2931 bdrv_child_free(*childp
);
2935 * Update permissions for old node. We're just taking a parent away, so
2936 * we're loosening restrictions. Errors of permission update are not
2937 * fatal in this case, ignore them.
2939 bdrv_refresh_perms(old_bs
, NULL
);
2942 * When the parent requiring a non-default AioContext is removed, the
2943 * node moves back to the main AioContext
2945 bdrv_try_set_aio_context(old_bs
, qemu_get_aio_context(), NULL
);
2950 * This function steals the reference to child_bs from the caller.
2951 * That reference is later dropped by bdrv_root_unref_child().
2953 * On failure NULL is returned, errp is set and the reference to
2954 * child_bs is also dropped.
2956 * The caller must hold the AioContext lock @child_bs, but not that of @ctx
2957 * (unless @child_bs is already in @ctx).
2959 BdrvChild
*bdrv_root_attach_child(BlockDriverState
*child_bs
,
2960 const char *child_name
,
2961 const BdrvChildClass
*child_class
,
2962 BdrvChildRole child_role
,
2963 uint64_t perm
, uint64_t shared_perm
,
2964 void *opaque
, Error
**errp
)
2967 BdrvChild
*child
= NULL
;
2968 Transaction
*tran
= tran_new();
2970 ret
= bdrv_attach_child_common(child_bs
, child_name
, child_class
,
2971 child_role
, perm
, shared_perm
, opaque
,
2972 &child
, tran
, errp
);
2977 ret
= bdrv_refresh_perms(child_bs
, errp
);
2980 tran_finalize(tran
, ret
);
2981 /* child is unset on failure by bdrv_attach_child_common_abort() */
2982 assert((ret
< 0) == !child
);
2984 bdrv_unref(child_bs
);
2989 * This function transfers the reference to child_bs from the caller
2990 * to parent_bs. That reference is later dropped by parent_bs on
2991 * bdrv_close() or if someone calls bdrv_unref_child().
2993 * On failure NULL is returned, errp is set and the reference to
2994 * child_bs is also dropped.
2996 * If @parent_bs and @child_bs are in different AioContexts, the caller must
2997 * hold the AioContext lock for @child_bs, but not for @parent_bs.
2999 BdrvChild
*bdrv_attach_child(BlockDriverState
*parent_bs
,
3000 BlockDriverState
*child_bs
,
3001 const char *child_name
,
3002 const BdrvChildClass
*child_class
,
3003 BdrvChildRole child_role
,
3007 BdrvChild
*child
= NULL
;
3008 Transaction
*tran
= tran_new();
3010 ret
= bdrv_attach_child_noperm(parent_bs
, child_bs
, child_name
, child_class
,
3011 child_role
, &child
, tran
, errp
);
3016 ret
= bdrv_refresh_perms(parent_bs
, errp
);
3022 tran_finalize(tran
, ret
);
3023 /* child is unset on failure by bdrv_attach_child_common_abort() */
3024 assert((ret
< 0) == !child
);
3026 bdrv_unref(child_bs
);
3031 /* Callers must ensure that child->frozen is false. */
3032 void bdrv_root_unref_child(BdrvChild
*child
)
3034 BlockDriverState
*child_bs
;
3036 child_bs
= child
->bs
;
3037 bdrv_detach_child(&child
);
3038 bdrv_unref(child_bs
);
3041 typedef struct BdrvSetInheritsFrom
{
3042 BlockDriverState
*bs
;
3043 BlockDriverState
*old_inherits_from
;
3044 } BdrvSetInheritsFrom
;
3046 static void bdrv_set_inherits_from_abort(void *opaque
)
3048 BdrvSetInheritsFrom
*s
= opaque
;
3050 s
->bs
->inherits_from
= s
->old_inherits_from
;
3053 static TransactionActionDrv bdrv_set_inherits_from_drv
= {
3054 .abort
= bdrv_set_inherits_from_abort
,
3058 /* @tran is allowed to be NULL. In this case no rollback is possible */
3059 static void bdrv_set_inherits_from(BlockDriverState
*bs
,
3060 BlockDriverState
*new_inherits_from
,
3064 BdrvSetInheritsFrom
*s
= g_new(BdrvSetInheritsFrom
, 1);
3066 *s
= (BdrvSetInheritsFrom
) {
3068 .old_inherits_from
= bs
->inherits_from
,
3071 tran_add(tran
, &bdrv_set_inherits_from_drv
, s
);
3074 bs
->inherits_from
= new_inherits_from
;
3078 * Clear all inherits_from pointers from children and grandchildren of
3079 * @root that point to @root, where necessary.
3080 * @tran is allowed to be NULL. In this case no rollback is possible
3082 static void bdrv_unset_inherits_from(BlockDriverState
*root
, BdrvChild
*child
,
3087 if (child
->bs
->inherits_from
== root
) {
3089 * Remove inherits_from only when the last reference between root and
3090 * child->bs goes away.
3092 QLIST_FOREACH(c
, &root
->children
, next
) {
3093 if (c
!= child
&& c
->bs
== child
->bs
) {
3098 bdrv_set_inherits_from(child
->bs
, NULL
, tran
);
3102 QLIST_FOREACH(c
, &child
->bs
->children
, next
) {
3103 bdrv_unset_inherits_from(root
, c
, tran
);
3107 /* Callers must ensure that child->frozen is false. */
3108 void bdrv_unref_child(BlockDriverState
*parent
, BdrvChild
*child
)
3110 if (child
== NULL
) {
3114 bdrv_unset_inherits_from(parent
, child
, NULL
);
3115 bdrv_root_unref_child(child
);
3119 static void bdrv_parent_cb_change_media(BlockDriverState
*bs
, bool load
)
3122 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
3123 if (c
->klass
->change_media
) {
3124 c
->klass
->change_media(c
, load
);
3129 /* Return true if you can reach parent going through child->inherits_from
3130 * recursively. If parent or child are NULL, return false */
3131 static bool bdrv_inherits_from_recursive(BlockDriverState
*child
,
3132 BlockDriverState
*parent
)
3134 while (child
&& child
!= parent
) {
3135 child
= child
->inherits_from
;
3138 return child
!= NULL
;
3142 * Return the BdrvChildRole for @bs's backing child. bs->backing is
3143 * mostly used for COW backing children (role = COW), but also for
3144 * filtered children (role = FILTERED | PRIMARY).
3146 static BdrvChildRole
bdrv_backing_role(BlockDriverState
*bs
)
3148 if (bs
->drv
&& bs
->drv
->is_filter
) {
3149 return BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
;
3151 return BDRV_CHILD_COW
;
3156 * Sets the bs->backing or bs->file link of a BDS. A new reference is created;
3157 * callers which don't need their own reference any more must call bdrv_unref().
3159 * Function doesn't update permissions, caller is responsible for this.
3161 static int bdrv_set_file_or_backing_noperm(BlockDriverState
*parent_bs
,
3162 BlockDriverState
*child_bs
,
3164 Transaction
*tran
, Error
**errp
)
3167 bool update_inherits_from
=
3168 bdrv_inherits_from_recursive(child_bs
, parent_bs
);
3169 BdrvChild
*child
= is_backing
? parent_bs
->backing
: parent_bs
->file
;
3172 if (!parent_bs
->drv
) {
3174 * Node without drv is an object without a class :/. TODO: finally fix
3175 * qcow2 driver to never clear bs->drv and implement format corruption
3176 * handling in other way.
3178 error_setg(errp
, "Node corrupted");
3182 if (child
&& child
->frozen
) {
3183 error_setg(errp
, "Cannot change frozen '%s' link from '%s' to '%s'",
3184 child
->name
, parent_bs
->node_name
, child
->bs
->node_name
);
3188 if (is_backing
&& !parent_bs
->drv
->is_filter
&&
3189 !parent_bs
->drv
->supports_backing
)
3191 error_setg(errp
, "Driver '%s' of node '%s' does not support backing "
3192 "files", parent_bs
->drv
->format_name
, parent_bs
->node_name
);
3196 if (parent_bs
->drv
->is_filter
) {
3197 role
= BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
;
3198 } else if (is_backing
) {
3199 role
= BDRV_CHILD_COW
;
3202 * We only can use same role as it is in existing child. We don't have
3203 * infrastructure to determine role of file child in generic way
3206 error_setg(errp
, "Cannot set file child to format node without "
3214 bdrv_unset_inherits_from(parent_bs
, child
, tran
);
3215 bdrv_remove_file_or_backing_child(parent_bs
, child
, tran
);
3222 ret
= bdrv_attach_child_noperm(parent_bs
, child_bs
,
3223 is_backing
? "backing" : "file",
3224 &child_of_bds
, role
,
3225 is_backing
? &parent_bs
->backing
:
3234 * If inherits_from pointed recursively to bs then let's update it to
3235 * point directly to bs (else it will become NULL).
3237 if (update_inherits_from
) {
3238 bdrv_set_inherits_from(child_bs
, parent_bs
, tran
);
3242 bdrv_refresh_limits(parent_bs
, tran
, NULL
);
3247 static int bdrv_set_backing_noperm(BlockDriverState
*bs
,
3248 BlockDriverState
*backing_hd
,
3249 Transaction
*tran
, Error
**errp
)
3251 return bdrv_set_file_or_backing_noperm(bs
, backing_hd
, true, tran
, errp
);
3254 int bdrv_set_backing_hd(BlockDriverState
*bs
, BlockDriverState
*backing_hd
,
3258 Transaction
*tran
= tran_new();
3260 ret
= bdrv_set_backing_noperm(bs
, backing_hd
, tran
, errp
);
3265 ret
= bdrv_refresh_perms(bs
, errp
);
3267 tran_finalize(tran
, ret
);
3273 * Opens the backing file for a BlockDriverState if not yet open
3275 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
3276 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
3277 * itself, all options starting with "${bdref_key}." are considered part of the
3280 * TODO Can this be unified with bdrv_open_image()?
3282 int bdrv_open_backing_file(BlockDriverState
*bs
, QDict
*parent_options
,
3283 const char *bdref_key
, Error
**errp
)
3285 char *backing_filename
= NULL
;
3286 char *bdref_key_dot
;
3287 const char *reference
= NULL
;
3289 bool implicit_backing
= false;
3290 BlockDriverState
*backing_hd
;
3292 QDict
*tmp_parent_options
= NULL
;
3293 Error
*local_err
= NULL
;
3295 if (bs
->backing
!= NULL
) {
3299 /* NULL means an empty set of options */
3300 if (parent_options
== NULL
) {
3301 tmp_parent_options
= qdict_new();
3302 parent_options
= tmp_parent_options
;
3305 bs
->open_flags
&= ~BDRV_O_NO_BACKING
;
3307 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
3308 qdict_extract_subqdict(parent_options
, &options
, bdref_key_dot
);
3309 g_free(bdref_key_dot
);
3312 * Caution: while qdict_get_try_str() is fine, getting non-string
3313 * types would require more care. When @parent_options come from
3314 * -blockdev or blockdev_add, its members are typed according to
3315 * the QAPI schema, but when they come from -drive, they're all
3318 reference
= qdict_get_try_str(parent_options
, bdref_key
);
3319 if (reference
|| qdict_haskey(options
, "file.filename")) {
3320 /* keep backing_filename NULL */
3321 } else if (bs
->backing_file
[0] == '\0' && qdict_size(options
) == 0) {
3322 qobject_unref(options
);
3325 if (qdict_size(options
) == 0) {
3326 /* If the user specifies options that do not modify the
3327 * backing file's behavior, we might still consider it the
3328 * implicit backing file. But it's easier this way, and
3329 * just specifying some of the backing BDS's options is
3330 * only possible with -drive anyway (otherwise the QAPI
3331 * schema forces the user to specify everything). */
3332 implicit_backing
= !strcmp(bs
->auto_backing_file
, bs
->backing_file
);
3335 backing_filename
= bdrv_get_full_backing_filename(bs
, &local_err
);
3338 error_propagate(errp
, local_err
);
3339 qobject_unref(options
);
3344 if (!bs
->drv
|| !bs
->drv
->supports_backing
) {
3346 error_setg(errp
, "Driver doesn't support backing files");
3347 qobject_unref(options
);
3352 bs
->backing_format
[0] != '\0' && !qdict_haskey(options
, "driver")) {
3353 qdict_put_str(options
, "driver", bs
->backing_format
);
3356 backing_hd
= bdrv_open_inherit(backing_filename
, reference
, options
, 0, bs
,
3357 &child_of_bds
, bdrv_backing_role(bs
), errp
);
3359 bs
->open_flags
|= BDRV_O_NO_BACKING
;
3360 error_prepend(errp
, "Could not open backing file: ");
3365 if (implicit_backing
) {
3366 bdrv_refresh_filename(backing_hd
);
3367 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
3368 backing_hd
->filename
);
3371 /* Hook up the backing file link; drop our reference, bs owns the
3372 * backing_hd reference now */
3373 ret
= bdrv_set_backing_hd(bs
, backing_hd
, errp
);
3374 bdrv_unref(backing_hd
);
3379 qdict_del(parent_options
, bdref_key
);
3382 g_free(backing_filename
);
3383 qobject_unref(tmp_parent_options
);
3387 static BlockDriverState
*
3388 bdrv_open_child_bs(const char *filename
, QDict
*options
, const char *bdref_key
,
3389 BlockDriverState
*parent
, const BdrvChildClass
*child_class
,
3390 BdrvChildRole child_role
, bool allow_none
, Error
**errp
)
3392 BlockDriverState
*bs
= NULL
;
3393 QDict
*image_options
;
3394 char *bdref_key_dot
;
3395 const char *reference
;
3397 assert(child_class
!= NULL
);
3399 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
3400 qdict_extract_subqdict(options
, &image_options
, bdref_key_dot
);
3401 g_free(bdref_key_dot
);
3404 * Caution: while qdict_get_try_str() is fine, getting non-string
3405 * types would require more care. When @options come from
3406 * -blockdev or blockdev_add, its members are typed according to
3407 * the QAPI schema, but when they come from -drive, they're all
3410 reference
= qdict_get_try_str(options
, bdref_key
);
3411 if (!filename
&& !reference
&& !qdict_size(image_options
)) {
3413 error_setg(errp
, "A block device must be specified for \"%s\"",
3416 qobject_unref(image_options
);
3420 bs
= bdrv_open_inherit(filename
, reference
, image_options
, 0,
3421 parent
, child_class
, child_role
, errp
);
3427 qdict_del(options
, bdref_key
);
3432 * Opens a disk image whose options are given as BlockdevRef in another block
3435 * If allow_none is true, no image will be opened if filename is false and no
3436 * BlockdevRef is given. NULL will be returned, but errp remains unset.
3438 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
3439 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
3440 * itself, all options starting with "${bdref_key}." are considered part of the
3443 * The BlockdevRef will be removed from the options QDict.
3445 BdrvChild
*bdrv_open_child(const char *filename
,
3446 QDict
*options
, const char *bdref_key
,
3447 BlockDriverState
*parent
,
3448 const BdrvChildClass
*child_class
,
3449 BdrvChildRole child_role
,
3450 bool allow_none
, Error
**errp
)
3452 BlockDriverState
*bs
;
3454 bs
= bdrv_open_child_bs(filename
, options
, bdref_key
, parent
, child_class
,
3455 child_role
, allow_none
, errp
);
3460 return bdrv_attach_child(parent
, bs
, bdref_key
, child_class
, child_role
,
3465 * TODO Future callers may need to specify parent/child_class in order for
3466 * option inheritance to work. Existing callers use it for the root node.
3468 BlockDriverState
*bdrv_open_blockdev_ref(BlockdevRef
*ref
, Error
**errp
)
3470 BlockDriverState
*bs
= NULL
;
3471 QObject
*obj
= NULL
;
3472 QDict
*qdict
= NULL
;
3473 const char *reference
= NULL
;
3476 if (ref
->type
== QTYPE_QSTRING
) {
3477 reference
= ref
->u
.reference
;
3479 BlockdevOptions
*options
= &ref
->u
.definition
;
3480 assert(ref
->type
== QTYPE_QDICT
);
3482 v
= qobject_output_visitor_new(&obj
);
3483 visit_type_BlockdevOptions(v
, NULL
, &options
, &error_abort
);
3484 visit_complete(v
, &obj
);
3486 qdict
= qobject_to(QDict
, obj
);
3487 qdict_flatten(qdict
);
3489 /* bdrv_open_inherit() defaults to the values in bdrv_flags (for
3490 * compatibility with other callers) rather than what we want as the
3491 * real defaults. Apply the defaults here instead. */
3492 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_DIRECT
, "off");
3493 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_NO_FLUSH
, "off");
3494 qdict_set_default_str(qdict
, BDRV_OPT_READ_ONLY
, "off");
3495 qdict_set_default_str(qdict
, BDRV_OPT_AUTO_READ_ONLY
, "off");
3499 bs
= bdrv_open_inherit(NULL
, reference
, qdict
, 0, NULL
, NULL
, 0, errp
);
3506 static BlockDriverState
*bdrv_append_temp_snapshot(BlockDriverState
*bs
,
3508 QDict
*snapshot_options
,
3511 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
3512 char *tmp_filename
= g_malloc0(PATH_MAX
+ 1);
3514 QemuOpts
*opts
= NULL
;
3515 BlockDriverState
*bs_snapshot
= NULL
;
3518 /* if snapshot, we create a temporary backing file and open it
3519 instead of opening 'filename' directly */
3521 /* Get the required size from the image */
3522 total_size
= bdrv_getlength(bs
);
3523 if (total_size
< 0) {
3524 error_setg_errno(errp
, -total_size
, "Could not get image size");
3528 /* Create the temporary image */
3529 ret
= get_tmp_filename(tmp_filename
, PATH_MAX
+ 1);
3531 error_setg_errno(errp
, -ret
, "Could not get temporary filename");
3535 opts
= qemu_opts_create(bdrv_qcow2
.create_opts
, NULL
, 0,
3537 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, total_size
, &error_abort
);
3538 ret
= bdrv_create(&bdrv_qcow2
, tmp_filename
, opts
, errp
);
3539 qemu_opts_del(opts
);
3541 error_prepend(errp
, "Could not create temporary overlay '%s': ",
3546 /* Prepare options QDict for the temporary file */
3547 qdict_put_str(snapshot_options
, "file.driver", "file");
3548 qdict_put_str(snapshot_options
, "file.filename", tmp_filename
);
3549 qdict_put_str(snapshot_options
, "driver", "qcow2");
3551 bs_snapshot
= bdrv_open(NULL
, NULL
, snapshot_options
, flags
, errp
);
3552 snapshot_options
= NULL
;
3557 ret
= bdrv_append(bs_snapshot
, bs
, errp
);
3564 qobject_unref(snapshot_options
);
3565 g_free(tmp_filename
);
3570 * Opens a disk image (raw, qcow2, vmdk, ...)
3572 * options is a QDict of options to pass to the block drivers, or NULL for an
3573 * empty set of options. The reference to the QDict belongs to the block layer
3574 * after the call (even on failure), so if the caller intends to reuse the
3575 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
3577 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
3578 * If it is not NULL, the referenced BDS will be reused.
3580 * The reference parameter may be used to specify an existing block device which
3581 * should be opened. If specified, neither options nor a filename may be given,
3582 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
3584 static BlockDriverState
*bdrv_open_inherit(const char *filename
,
3585 const char *reference
,
3586 QDict
*options
, int flags
,
3587 BlockDriverState
*parent
,
3588 const BdrvChildClass
*child_class
,
3589 BdrvChildRole child_role
,
3593 BlockBackend
*file
= NULL
;
3594 BlockDriverState
*bs
;
3595 BlockDriver
*drv
= NULL
;
3597 const char *drvname
;
3598 const char *backing
;
3599 Error
*local_err
= NULL
;
3600 QDict
*snapshot_options
= NULL
;
3601 int snapshot_flags
= 0;
3603 assert(!child_class
|| !flags
);
3604 assert(!child_class
== !parent
);
3607 bool options_non_empty
= options
? qdict_size(options
) : false;
3608 qobject_unref(options
);
3610 if (filename
|| options_non_empty
) {
3611 error_setg(errp
, "Cannot reference an existing block device with "
3612 "additional options or a new filename");
3616 bs
= bdrv_lookup_bs(reference
, reference
, errp
);
3627 /* NULL means an empty set of options */
3628 if (options
== NULL
) {
3629 options
= qdict_new();
3632 /* json: syntax counts as explicit options, as if in the QDict */
3633 parse_json_protocol(options
, &filename
, &local_err
);
3638 bs
->explicit_options
= qdict_clone_shallow(options
);
3641 bool parent_is_format
;
3644 parent_is_format
= parent
->drv
->is_format
;
3647 * parent->drv is not set yet because this node is opened for
3648 * (potential) format probing. That means that @parent is going
3649 * to be a format node.
3651 parent_is_format
= true;
3654 bs
->inherits_from
= parent
;
3655 child_class
->inherit_options(child_role
, parent_is_format
,
3657 parent
->open_flags
, parent
->options
);
3660 ret
= bdrv_fill_options(&options
, filename
, &flags
, &local_err
);
3666 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
3667 * Caution: getting a boolean member of @options requires care.
3668 * When @options come from -blockdev or blockdev_add, members are
3669 * typed according to the QAPI schema, but when they come from
3670 * -drive, they're all QString.
3672 if (g_strcmp0(qdict_get_try_str(options
, BDRV_OPT_READ_ONLY
), "on") &&
3673 !qdict_get_try_bool(options
, BDRV_OPT_READ_ONLY
, false)) {
3674 flags
|= (BDRV_O_RDWR
| BDRV_O_ALLOW_RDWR
);
3676 flags
&= ~BDRV_O_RDWR
;
3679 if (flags
& BDRV_O_SNAPSHOT
) {
3680 snapshot_options
= qdict_new();
3681 bdrv_temp_snapshot_options(&snapshot_flags
, snapshot_options
,
3683 /* Let bdrv_backing_options() override "read-only" */
3684 qdict_del(options
, BDRV_OPT_READ_ONLY
);
3685 bdrv_inherited_options(BDRV_CHILD_COW
, true,
3686 &flags
, options
, flags
, options
);
3689 bs
->open_flags
= flags
;
3690 bs
->options
= options
;
3691 options
= qdict_clone_shallow(options
);
3693 /* Find the right image format driver */
3694 /* See cautionary note on accessing @options above */
3695 drvname
= qdict_get_try_str(options
, "driver");
3697 drv
= bdrv_find_format(drvname
);
3699 error_setg(errp
, "Unknown driver: '%s'", drvname
);
3704 assert(drvname
|| !(flags
& BDRV_O_PROTOCOL
));
3706 /* See cautionary note on accessing @options above */
3707 backing
= qdict_get_try_str(options
, "backing");
3708 if (qobject_to(QNull
, qdict_get(options
, "backing")) != NULL
||
3709 (backing
&& *backing
== '\0'))
3712 warn_report("Use of \"backing\": \"\" is deprecated; "
3713 "use \"backing\": null instead");
3715 flags
|= BDRV_O_NO_BACKING
;
3716 qdict_del(bs
->explicit_options
, "backing");
3717 qdict_del(bs
->options
, "backing");
3718 qdict_del(options
, "backing");
3721 /* Open image file without format layer. This BlockBackend is only used for
3722 * probing, the block drivers will do their own bdrv_open_child() for the
3723 * same BDS, which is why we put the node name back into options. */
3724 if ((flags
& BDRV_O_PROTOCOL
) == 0) {
3725 BlockDriverState
*file_bs
;
3727 file_bs
= bdrv_open_child_bs(filename
, options
, "file", bs
,
3728 &child_of_bds
, BDRV_CHILD_IMAGE
,
3733 if (file_bs
!= NULL
) {
3734 /* Not requesting BLK_PERM_CONSISTENT_READ because we're only
3735 * looking at the header to guess the image format. This works even
3736 * in cases where a guest would not see a consistent state. */
3737 file
= blk_new(bdrv_get_aio_context(file_bs
), 0, BLK_PERM_ALL
);
3738 blk_insert_bs(file
, file_bs
, &local_err
);
3739 bdrv_unref(file_bs
);
3744 qdict_put_str(options
, "file", bdrv_get_node_name(file_bs
));
3748 /* Image format probing */
3751 ret
= find_image_format(file
, filename
, &drv
, &local_err
);
3756 * This option update would logically belong in bdrv_fill_options(),
3757 * but we first need to open bs->file for the probing to work, while
3758 * opening bs->file already requires the (mostly) final set of options
3759 * so that cache mode etc. can be inherited.
3761 * Adding the driver later is somewhat ugly, but it's not an option
3762 * that would ever be inherited, so it's correct. We just need to make
3763 * sure to update both bs->options (which has the full effective
3764 * options for bs) and options (which has file.* already removed).
3766 qdict_put_str(bs
->options
, "driver", drv
->format_name
);
3767 qdict_put_str(options
, "driver", drv
->format_name
);
3769 error_setg(errp
, "Must specify either driver or file");
3773 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
3774 assert(!!(flags
& BDRV_O_PROTOCOL
) == !!drv
->bdrv_file_open
);
3775 /* file must be NULL if a protocol BDS is about to be created
3776 * (the inverse results in an error message from bdrv_open_common()) */
3777 assert(!(flags
& BDRV_O_PROTOCOL
) || !file
);
3779 /* Open the image */
3780 ret
= bdrv_open_common(bs
, file
, options
, &local_err
);
3790 /* If there is a backing file, use it */
3791 if ((flags
& BDRV_O_NO_BACKING
) == 0) {
3792 ret
= bdrv_open_backing_file(bs
, options
, "backing", &local_err
);
3794 goto close_and_fail
;
3798 /* Remove all children options and references
3799 * from bs->options and bs->explicit_options */
3800 QLIST_FOREACH(child
, &bs
->children
, next
) {
3801 char *child_key_dot
;
3802 child_key_dot
= g_strdup_printf("%s.", child
->name
);
3803 qdict_extract_subqdict(bs
->explicit_options
, NULL
, child_key_dot
);
3804 qdict_extract_subqdict(bs
->options
, NULL
, child_key_dot
);
3805 qdict_del(bs
->explicit_options
, child
->name
);
3806 qdict_del(bs
->options
, child
->name
);
3807 g_free(child_key_dot
);
3810 /* Check if any unknown options were used */
3811 if (qdict_size(options
) != 0) {
3812 const QDictEntry
*entry
= qdict_first(options
);
3813 if (flags
& BDRV_O_PROTOCOL
) {
3814 error_setg(errp
, "Block protocol '%s' doesn't support the option "
3815 "'%s'", drv
->format_name
, entry
->key
);
3818 "Block format '%s' does not support the option '%s'",
3819 drv
->format_name
, entry
->key
);
3822 goto close_and_fail
;
3825 bdrv_parent_cb_change_media(bs
, true);
3827 qobject_unref(options
);
3830 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
3831 * temporary snapshot afterwards. */
3832 if (snapshot_flags
) {
3833 BlockDriverState
*snapshot_bs
;
3834 snapshot_bs
= bdrv_append_temp_snapshot(bs
, snapshot_flags
,
3835 snapshot_options
, &local_err
);
3836 snapshot_options
= NULL
;
3838 goto close_and_fail
;
3840 /* We are not going to return bs but the overlay on top of it
3841 * (snapshot_bs); thus, we have to drop the strong reference to bs
3842 * (which we obtained by calling bdrv_new()). bs will not be deleted,
3843 * though, because the overlay still has a reference to it. */
3852 qobject_unref(snapshot_options
);
3853 qobject_unref(bs
->explicit_options
);
3854 qobject_unref(bs
->options
);
3855 qobject_unref(options
);
3857 bs
->explicit_options
= NULL
;
3859 error_propagate(errp
, local_err
);
3864 qobject_unref(snapshot_options
);
3865 qobject_unref(options
);
3866 error_propagate(errp
, local_err
);
3870 BlockDriverState
*bdrv_open(const char *filename
, const char *reference
,
3871 QDict
*options
, int flags
, Error
**errp
)
3873 return bdrv_open_inherit(filename
, reference
, options
, flags
, NULL
,
3877 /* Return true if the NULL-terminated @list contains @str */
3878 static bool is_str_in_list(const char *str
, const char *const *list
)
3882 for (i
= 0; list
[i
] != NULL
; i
++) {
3883 if (!strcmp(str
, list
[i
])) {
3892 * Check that every option set in @bs->options is also set in
3895 * Options listed in the common_options list and in
3896 * @bs->drv->mutable_opts are skipped.
3898 * Return 0 on success, otherwise return -EINVAL and set @errp.
3900 static int bdrv_reset_options_allowed(BlockDriverState
*bs
,
3901 const QDict
*new_opts
, Error
**errp
)
3903 const QDictEntry
*e
;
3904 /* These options are common to all block drivers and are handled
3905 * in bdrv_reopen_prepare() so they can be left out of @new_opts */
3906 const char *const common_options
[] = {
3907 "node-name", "discard", "cache.direct", "cache.no-flush",
3908 "read-only", "auto-read-only", "detect-zeroes", NULL
3911 for (e
= qdict_first(bs
->options
); e
; e
= qdict_next(bs
->options
, e
)) {
3912 if (!qdict_haskey(new_opts
, e
->key
) &&
3913 !is_str_in_list(e
->key
, common_options
) &&
3914 !is_str_in_list(e
->key
, bs
->drv
->mutable_opts
)) {
3915 error_setg(errp
, "Option '%s' cannot be reset "
3916 "to its default value", e
->key
);
3925 * Returns true if @child can be reached recursively from @bs
3927 static bool bdrv_recurse_has_child(BlockDriverState
*bs
,
3928 BlockDriverState
*child
)
3936 QLIST_FOREACH(c
, &bs
->children
, next
) {
3937 if (bdrv_recurse_has_child(c
->bs
, child
)) {
3946 * Adds a BlockDriverState to a simple queue for an atomic, transactional
3947 * reopen of multiple devices.
3949 * bs_queue can either be an existing BlockReopenQueue that has had QTAILQ_INIT
3950 * already performed, or alternatively may be NULL a new BlockReopenQueue will
3951 * be created and initialized. This newly created BlockReopenQueue should be
3952 * passed back in for subsequent calls that are intended to be of the same
3955 * bs is the BlockDriverState to add to the reopen queue.
3957 * options contains the changed options for the associated bs
3958 * (the BlockReopenQueue takes ownership)
3960 * flags contains the open flags for the associated bs
3962 * returns a pointer to bs_queue, which is either the newly allocated
3963 * bs_queue, or the existing bs_queue being used.
3965 * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple().
3967 static BlockReopenQueue
*bdrv_reopen_queue_child(BlockReopenQueue
*bs_queue
,
3968 BlockDriverState
*bs
,
3970 const BdrvChildClass
*klass
,
3972 bool parent_is_format
,
3973 QDict
*parent_options
,
3979 BlockReopenQueueEntry
*bs_entry
;
3981 QDict
*old_options
, *explicit_options
, *options_copy
;
3985 /* Make sure that the caller remembered to use a drained section. This is
3986 * important to avoid graph changes between the recursive queuing here and
3987 * bdrv_reopen_multiple(). */
3988 assert(bs
->quiesce_counter
> 0);
3990 if (bs_queue
== NULL
) {
3991 bs_queue
= g_new0(BlockReopenQueue
, 1);
3992 QTAILQ_INIT(bs_queue
);
3996 options
= qdict_new();
3999 /* Check if this BlockDriverState is already in the queue */
4000 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4001 if (bs
== bs_entry
->state
.bs
) {
4007 * Precedence of options:
4008 * 1. Explicitly passed in options (highest)
4009 * 2. Retained from explicitly set options of bs
4010 * 3. Inherited from parent node
4011 * 4. Retained from effective options of bs
4014 /* Old explicitly set values (don't overwrite by inherited value) */
4015 if (bs_entry
|| keep_old_opts
) {
4016 old_options
= qdict_clone_shallow(bs_entry
?
4017 bs_entry
->state
.explicit_options
:
4018 bs
->explicit_options
);
4019 bdrv_join_options(bs
, options
, old_options
);
4020 qobject_unref(old_options
);
4023 explicit_options
= qdict_clone_shallow(options
);
4025 /* Inherit from parent node */
4026 if (parent_options
) {
4028 klass
->inherit_options(role
, parent_is_format
, &flags
, options
,
4029 parent_flags
, parent_options
);
4031 flags
= bdrv_get_flags(bs
);
4034 if (keep_old_opts
) {
4035 /* Old values are used for options that aren't set yet */
4036 old_options
= qdict_clone_shallow(bs
->options
);
4037 bdrv_join_options(bs
, options
, old_options
);
4038 qobject_unref(old_options
);
4041 /* We have the final set of options so let's update the flags */
4042 options_copy
= qdict_clone_shallow(options
);
4043 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
4044 qemu_opts_absorb_qdict(opts
, options_copy
, NULL
);
4045 update_flags_from_options(&flags
, opts
);
4046 qemu_opts_del(opts
);
4047 qobject_unref(options_copy
);
4049 /* bdrv_open_inherit() sets and clears some additional flags internally */
4050 flags
&= ~BDRV_O_PROTOCOL
;
4051 if (flags
& BDRV_O_RDWR
) {
4052 flags
|= BDRV_O_ALLOW_RDWR
;
4056 bs_entry
= g_new0(BlockReopenQueueEntry
, 1);
4057 QTAILQ_INSERT_TAIL(bs_queue
, bs_entry
, entry
);
4059 qobject_unref(bs_entry
->state
.options
);
4060 qobject_unref(bs_entry
->state
.explicit_options
);
4063 bs_entry
->state
.bs
= bs
;
4064 bs_entry
->state
.options
= options
;
4065 bs_entry
->state
.explicit_options
= explicit_options
;
4066 bs_entry
->state
.flags
= flags
;
4069 * If keep_old_opts is false then it means that unspecified
4070 * options must be reset to their original value. We don't allow
4071 * resetting 'backing' but we need to know if the option is
4072 * missing in order to decide if we have to return an error.
4074 if (!keep_old_opts
) {
4075 bs_entry
->state
.backing_missing
=
4076 !qdict_haskey(options
, "backing") &&
4077 !qdict_haskey(options
, "backing.driver");
4080 QLIST_FOREACH(child
, &bs
->children
, next
) {
4081 QDict
*new_child_options
= NULL
;
4082 bool child_keep_old
= keep_old_opts
;
4084 /* reopen can only change the options of block devices that were
4085 * implicitly created and inherited options. For other (referenced)
4086 * block devices, a syntax like "backing.foo" results in an error. */
4087 if (child
->bs
->inherits_from
!= bs
) {
4091 /* Check if the options contain a child reference */
4092 if (qdict_haskey(options
, child
->name
)) {
4093 const char *childref
= qdict_get_try_str(options
, child
->name
);
4095 * The current child must not be reopened if the child
4096 * reference is null or points to a different node.
4098 if (g_strcmp0(childref
, child
->bs
->node_name
)) {
4102 * If the child reference points to the current child then
4103 * reopen it with its existing set of options (note that
4104 * it can still inherit new options from the parent).
4106 child_keep_old
= true;
4108 /* Extract child options ("child-name.*") */
4109 char *child_key_dot
= g_strdup_printf("%s.", child
->name
);
4110 qdict_extract_subqdict(explicit_options
, NULL
, child_key_dot
);
4111 qdict_extract_subqdict(options
, &new_child_options
, child_key_dot
);
4112 g_free(child_key_dot
);
4115 bdrv_reopen_queue_child(bs_queue
, child
->bs
, new_child_options
,
4116 child
->klass
, child
->role
, bs
->drv
->is_format
,
4117 options
, flags
, child_keep_old
);
4123 BlockReopenQueue
*bdrv_reopen_queue(BlockReopenQueue
*bs_queue
,
4124 BlockDriverState
*bs
,
4125 QDict
*options
, bool keep_old_opts
)
4127 return bdrv_reopen_queue_child(bs_queue
, bs
, options
, NULL
, 0, false,
4128 NULL
, 0, keep_old_opts
);
4131 void bdrv_reopen_queue_free(BlockReopenQueue
*bs_queue
)
4134 BlockReopenQueueEntry
*bs_entry
, *next
;
4135 QTAILQ_FOREACH_SAFE(bs_entry
, bs_queue
, entry
, next
) {
4136 qobject_unref(bs_entry
->state
.explicit_options
);
4137 qobject_unref(bs_entry
->state
.options
);
4145 * Reopen multiple BlockDriverStates atomically & transactionally.
4147 * The queue passed in (bs_queue) must have been built up previous
4148 * via bdrv_reopen_queue().
4150 * Reopens all BDS specified in the queue, with the appropriate
4151 * flags. All devices are prepared for reopen, and failure of any
4152 * device will cause all device changes to be abandoned, and intermediate
4155 * If all devices prepare successfully, then the changes are committed
4158 * All affected nodes must be drained between bdrv_reopen_queue() and
4159 * bdrv_reopen_multiple().
4161 * To be called from the main thread, with all other AioContexts unlocked.
4163 int bdrv_reopen_multiple(BlockReopenQueue
*bs_queue
, Error
**errp
)
4166 BlockReopenQueueEntry
*bs_entry
, *next
;
4168 Transaction
*tran
= tran_new();
4169 g_autoptr(GHashTable
) found
= NULL
;
4170 g_autoptr(GSList
) refresh_list
= NULL
;
4172 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
4173 assert(bs_queue
!= NULL
);
4175 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4176 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4177 aio_context_acquire(ctx
);
4178 ret
= bdrv_flush(bs_entry
->state
.bs
);
4179 aio_context_release(ctx
);
4181 error_setg_errno(errp
, -ret
, "Error flushing drive");
4186 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4187 assert(bs_entry
->state
.bs
->quiesce_counter
> 0);
4188 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4189 aio_context_acquire(ctx
);
4190 ret
= bdrv_reopen_prepare(&bs_entry
->state
, bs_queue
, tran
, errp
);
4191 aio_context_release(ctx
);
4195 bs_entry
->prepared
= true;
4198 found
= g_hash_table_new(NULL
, NULL
);
4199 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4200 BDRVReopenState
*state
= &bs_entry
->state
;
4202 refresh_list
= bdrv_topological_dfs(refresh_list
, found
, state
->bs
);
4203 if (state
->old_backing_bs
) {
4204 refresh_list
= bdrv_topological_dfs(refresh_list
, found
,
4205 state
->old_backing_bs
);
4207 if (state
->old_file_bs
) {
4208 refresh_list
= bdrv_topological_dfs(refresh_list
, found
,
4209 state
->old_file_bs
);
4214 * Note that file-posix driver rely on permission update done during reopen
4215 * (even if no permission changed), because it wants "new" permissions for
4216 * reconfiguring the fd and that's why it does it in raw_check_perm(), not
4217 * in raw_reopen_prepare() which is called with "old" permissions.
4219 ret
= bdrv_list_refresh_perms(refresh_list
, bs_queue
, tran
, errp
);
4225 * If we reach this point, we have success and just need to apply the
4228 * Reverse order is used to comfort qcow2 driver: on commit it need to write
4229 * IN_USE flag to the image, to mark bitmaps in the image as invalid. But
4230 * children are usually goes after parents in reopen-queue, so go from last
4233 QTAILQ_FOREACH_REVERSE(bs_entry
, bs_queue
, entry
) {
4234 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4235 aio_context_acquire(ctx
);
4236 bdrv_reopen_commit(&bs_entry
->state
);
4237 aio_context_release(ctx
);
4242 QTAILQ_FOREACH_REVERSE(bs_entry
, bs_queue
, entry
) {
4243 BlockDriverState
*bs
= bs_entry
->state
.bs
;
4245 if (bs
->drv
->bdrv_reopen_commit_post
) {
4246 ctx
= bdrv_get_aio_context(bs
);
4247 aio_context_acquire(ctx
);
4248 bs
->drv
->bdrv_reopen_commit_post(&bs_entry
->state
);
4249 aio_context_release(ctx
);
4258 QTAILQ_FOREACH_SAFE(bs_entry
, bs_queue
, entry
, next
) {
4259 if (bs_entry
->prepared
) {
4260 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4261 aio_context_acquire(ctx
);
4262 bdrv_reopen_abort(&bs_entry
->state
);
4263 aio_context_release(ctx
);
4268 bdrv_reopen_queue_free(bs_queue
);
4273 int bdrv_reopen(BlockDriverState
*bs
, QDict
*opts
, bool keep_old_opts
,
4276 AioContext
*ctx
= bdrv_get_aio_context(bs
);
4277 BlockReopenQueue
*queue
;
4280 bdrv_subtree_drained_begin(bs
);
4281 if (ctx
!= qemu_get_aio_context()) {
4282 aio_context_release(ctx
);
4285 queue
= bdrv_reopen_queue(NULL
, bs
, opts
, keep_old_opts
);
4286 ret
= bdrv_reopen_multiple(queue
, errp
);
4288 if (ctx
!= qemu_get_aio_context()) {
4289 aio_context_acquire(ctx
);
4291 bdrv_subtree_drained_end(bs
);
4296 int bdrv_reopen_set_read_only(BlockDriverState
*bs
, bool read_only
,
4299 QDict
*opts
= qdict_new();
4301 qdict_put_bool(opts
, BDRV_OPT_READ_ONLY
, read_only
);
4303 return bdrv_reopen(bs
, opts
, true, errp
);
4307 * Take a BDRVReopenState and check if the value of 'backing' in the
4308 * reopen_state->options QDict is valid or not.
4310 * If 'backing' is missing from the QDict then return 0.
4312 * If 'backing' contains the node name of the backing file of
4313 * reopen_state->bs then return 0.
4315 * If 'backing' contains a different node name (or is null) then check
4316 * whether the current backing file can be replaced with the new one.
4317 * If that's the case then reopen_state->replace_backing_bs is set to
4318 * true and reopen_state->new_backing_bs contains a pointer to the new
4319 * backing BlockDriverState (or NULL).
4321 * Return 0 on success, otherwise return < 0 and set @errp.
4323 static int bdrv_reopen_parse_file_or_backing(BDRVReopenState
*reopen_state
,
4324 bool is_backing
, Transaction
*tran
,
4327 BlockDriverState
*bs
= reopen_state
->bs
;
4328 BlockDriverState
*new_child_bs
;
4329 BlockDriverState
*old_child_bs
= is_backing
? child_bs(bs
->backing
) :
4331 const char *child_name
= is_backing
? "backing" : "file";
4335 value
= qdict_get(reopen_state
->options
, child_name
);
4336 if (value
== NULL
) {
4340 switch (qobject_type(value
)) {
4342 assert(is_backing
); /* The 'file' option does not allow a null value */
4343 new_child_bs
= NULL
;
4346 str
= qstring_get_str(qobject_to(QString
, value
));
4347 new_child_bs
= bdrv_lookup_bs(NULL
, str
, errp
);
4348 if (new_child_bs
== NULL
) {
4350 } else if (bdrv_recurse_has_child(new_child_bs
, bs
)) {
4351 error_setg(errp
, "Making '%s' a %s child of '%s' would create a "
4352 "cycle", str
, child_name
, bs
->node_name
);
4358 * The options QDict has been flattened, so 'backing' and 'file'
4359 * do not allow any other data type here.
4361 g_assert_not_reached();
4364 if (old_child_bs
== new_child_bs
) {
4369 if (bdrv_skip_implicit_filters(old_child_bs
) == new_child_bs
) {
4373 if (old_child_bs
->implicit
) {
4374 error_setg(errp
, "Cannot replace implicit %s child of %s",
4375 child_name
, bs
->node_name
);
4380 if (bs
->drv
->is_filter
&& !old_child_bs
) {
4382 * Filters always have a file or a backing child, so we are trying to
4383 * change wrong child
4385 error_setg(errp
, "'%s' is a %s filter node that does not support a "
4386 "%s child", bs
->node_name
, bs
->drv
->format_name
, child_name
);
4391 reopen_state
->old_backing_bs
= old_child_bs
;
4393 reopen_state
->old_file_bs
= old_child_bs
;
4396 return bdrv_set_file_or_backing_noperm(bs
, new_child_bs
, is_backing
,
4401 * Prepares a BlockDriverState for reopen. All changes are staged in the
4402 * 'opaque' field of the BDRVReopenState, which is used and allocated by
4403 * the block driver layer .bdrv_reopen_prepare()
4405 * bs is the BlockDriverState to reopen
4406 * flags are the new open flags
4407 * queue is the reopen queue
4409 * Returns 0 on success, non-zero on error. On error errp will be set
4412 * On failure, bdrv_reopen_abort() will be called to clean up any data.
4413 * It is the responsibility of the caller to then call the abort() or
4414 * commit() for any other BDS that have been left in a prepare() state
4417 static int bdrv_reopen_prepare(BDRVReopenState
*reopen_state
,
4418 BlockReopenQueue
*queue
,
4419 Transaction
*change_child_tran
, Error
**errp
)
4423 Error
*local_err
= NULL
;
4426 QDict
*orig_reopen_opts
;
4427 char *discard
= NULL
;
4429 bool drv_prepared
= false;
4431 assert(reopen_state
!= NULL
);
4432 assert(reopen_state
->bs
->drv
!= NULL
);
4433 drv
= reopen_state
->bs
->drv
;
4435 /* This function and each driver's bdrv_reopen_prepare() remove
4436 * entries from reopen_state->options as they are processed, so
4437 * we need to make a copy of the original QDict. */
4438 orig_reopen_opts
= qdict_clone_shallow(reopen_state
->options
);
4440 /* Process generic block layer options */
4441 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
4442 if (!qemu_opts_absorb_qdict(opts
, reopen_state
->options
, errp
)) {
4447 /* This was already called in bdrv_reopen_queue_child() so the flags
4448 * are up-to-date. This time we simply want to remove the options from
4449 * QemuOpts in order to indicate that they have been processed. */
4450 old_flags
= reopen_state
->flags
;
4451 update_flags_from_options(&reopen_state
->flags
, opts
);
4452 assert(old_flags
== reopen_state
->flags
);
4454 discard
= qemu_opt_get_del(opts
, BDRV_OPT_DISCARD
);
4455 if (discard
!= NULL
) {
4456 if (bdrv_parse_discard_flags(discard
, &reopen_state
->flags
) != 0) {
4457 error_setg(errp
, "Invalid discard option");
4463 reopen_state
->detect_zeroes
=
4464 bdrv_parse_detect_zeroes(opts
, reopen_state
->flags
, &local_err
);
4466 error_propagate(errp
, local_err
);
4471 /* All other options (including node-name and driver) must be unchanged.
4472 * Put them back into the QDict, so that they are checked at the end
4473 * of this function. */
4474 qemu_opts_to_qdict(opts
, reopen_state
->options
);
4476 /* If we are to stay read-only, do not allow permission change
4477 * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is
4478 * not set, or if the BDS still has copy_on_read enabled */
4479 read_only
= !(reopen_state
->flags
& BDRV_O_RDWR
);
4480 ret
= bdrv_can_set_read_only(reopen_state
->bs
, read_only
, true, &local_err
);
4482 error_propagate(errp
, local_err
);
4486 if (drv
->bdrv_reopen_prepare
) {
4488 * If a driver-specific option is missing, it means that we
4489 * should reset it to its default value.
4490 * But not all options allow that, so we need to check it first.
4492 ret
= bdrv_reset_options_allowed(reopen_state
->bs
,
4493 reopen_state
->options
, errp
);
4498 ret
= drv
->bdrv_reopen_prepare(reopen_state
, queue
, &local_err
);
4500 if (local_err
!= NULL
) {
4501 error_propagate(errp
, local_err
);
4503 bdrv_refresh_filename(reopen_state
->bs
);
4504 error_setg(errp
, "failed while preparing to reopen image '%s'",
4505 reopen_state
->bs
->filename
);
4510 /* It is currently mandatory to have a bdrv_reopen_prepare()
4511 * handler for each supported drv. */
4512 error_setg(errp
, "Block format '%s' used by node '%s' "
4513 "does not support reopening files", drv
->format_name
,
4514 bdrv_get_device_or_node_name(reopen_state
->bs
));
4519 drv_prepared
= true;
4522 * We must provide the 'backing' option if the BDS has a backing
4523 * file or if the image file has a backing file name as part of
4524 * its metadata. Otherwise the 'backing' option can be omitted.
4526 if (drv
->supports_backing
&& reopen_state
->backing_missing
&&
4527 (reopen_state
->bs
->backing
|| reopen_state
->bs
->backing_file
[0])) {
4528 error_setg(errp
, "backing is missing for '%s'",
4529 reopen_state
->bs
->node_name
);
4535 * Allow changing the 'backing' option. The new value can be
4536 * either a reference to an existing node (using its node name)
4537 * or NULL to simply detach the current backing file.
4539 ret
= bdrv_reopen_parse_file_or_backing(reopen_state
, true,
4540 change_child_tran
, errp
);
4544 qdict_del(reopen_state
->options
, "backing");
4546 /* Allow changing the 'file' option. In this case NULL is not allowed */
4547 ret
= bdrv_reopen_parse_file_or_backing(reopen_state
, false,
4548 change_child_tran
, errp
);
4552 qdict_del(reopen_state
->options
, "file");
4554 /* Options that are not handled are only okay if they are unchanged
4555 * compared to the old state. It is expected that some options are only
4556 * used for the initial open, but not reopen (e.g. filename) */
4557 if (qdict_size(reopen_state
->options
)) {
4558 const QDictEntry
*entry
= qdict_first(reopen_state
->options
);
4561 QObject
*new = entry
->value
;
4562 QObject
*old
= qdict_get(reopen_state
->bs
->options
, entry
->key
);
4564 /* Allow child references (child_name=node_name) as long as they
4565 * point to the current child (i.e. everything stays the same). */
4566 if (qobject_type(new) == QTYPE_QSTRING
) {
4568 QLIST_FOREACH(child
, &reopen_state
->bs
->children
, next
) {
4569 if (!strcmp(child
->name
, entry
->key
)) {
4575 if (!strcmp(child
->bs
->node_name
,
4576 qstring_get_str(qobject_to(QString
, new)))) {
4577 continue; /* Found child with this name, skip option */
4583 * TODO: When using -drive to specify blockdev options, all values
4584 * will be strings; however, when using -blockdev, blockdev-add or
4585 * filenames using the json:{} pseudo-protocol, they will be
4587 * In contrast, reopening options are (currently) always strings
4588 * (because you can only specify them through qemu-io; all other
4589 * callers do not specify any options).
4590 * Therefore, when using anything other than -drive to create a BDS,
4591 * this cannot detect non-string options as unchanged, because
4592 * qobject_is_equal() always returns false for objects of different
4593 * type. In the future, this should be remedied by correctly typing
4594 * all options. For now, this is not too big of an issue because
4595 * the user can simply omit options which cannot be changed anyway,
4596 * so they will stay unchanged.
4598 if (!qobject_is_equal(new, old
)) {
4599 error_setg(errp
, "Cannot change the option '%s'", entry
->key
);
4603 } while ((entry
= qdict_next(reopen_state
->options
, entry
)));
4608 /* Restore the original reopen_state->options QDict */
4609 qobject_unref(reopen_state
->options
);
4610 reopen_state
->options
= qobject_ref(orig_reopen_opts
);
4613 if (ret
< 0 && drv_prepared
) {
4614 /* drv->bdrv_reopen_prepare() has succeeded, so we need to
4615 * call drv->bdrv_reopen_abort() before signaling an error
4616 * (bdrv_reopen_multiple() will not call bdrv_reopen_abort()
4617 * when the respective bdrv_reopen_prepare() has failed) */
4618 if (drv
->bdrv_reopen_abort
) {
4619 drv
->bdrv_reopen_abort(reopen_state
);
4622 qemu_opts_del(opts
);
4623 qobject_unref(orig_reopen_opts
);
4629 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
4630 * makes them final by swapping the staging BlockDriverState contents into
4631 * the active BlockDriverState contents.
4633 static void bdrv_reopen_commit(BDRVReopenState
*reopen_state
)
4636 BlockDriverState
*bs
;
4639 assert(reopen_state
!= NULL
);
4640 bs
= reopen_state
->bs
;
4642 assert(drv
!= NULL
);
4644 /* If there are any driver level actions to take */
4645 if (drv
->bdrv_reopen_commit
) {
4646 drv
->bdrv_reopen_commit(reopen_state
);
4649 /* set BDS specific flags now */
4650 qobject_unref(bs
->explicit_options
);
4651 qobject_unref(bs
->options
);
4652 qobject_ref(reopen_state
->explicit_options
);
4653 qobject_ref(reopen_state
->options
);
4655 bs
->explicit_options
= reopen_state
->explicit_options
;
4656 bs
->options
= reopen_state
->options
;
4657 bs
->open_flags
= reopen_state
->flags
;
4658 bs
->detect_zeroes
= reopen_state
->detect_zeroes
;
4660 /* Remove child references from bs->options and bs->explicit_options.
4661 * Child options were already removed in bdrv_reopen_queue_child() */
4662 QLIST_FOREACH(child
, &bs
->children
, next
) {
4663 qdict_del(bs
->explicit_options
, child
->name
);
4664 qdict_del(bs
->options
, child
->name
);
4666 /* backing is probably removed, so it's not handled by previous loop */
4667 qdict_del(bs
->explicit_options
, "backing");
4668 qdict_del(bs
->options
, "backing");
4670 bdrv_refresh_limits(bs
, NULL
, NULL
);
4674 * Abort the reopen, and delete and free the staged changes in
4677 static void bdrv_reopen_abort(BDRVReopenState
*reopen_state
)
4681 assert(reopen_state
!= NULL
);
4682 drv
= reopen_state
->bs
->drv
;
4683 assert(drv
!= NULL
);
4685 if (drv
->bdrv_reopen_abort
) {
4686 drv
->bdrv_reopen_abort(reopen_state
);
4691 static void bdrv_close(BlockDriverState
*bs
)
4693 BdrvAioNotifier
*ban
, *ban_next
;
4694 BdrvChild
*child
, *next
;
4696 assert(!bs
->refcnt
);
4698 bdrv_drained_begin(bs
); /* complete I/O */
4700 bdrv_drain(bs
); /* in case flush left pending I/O */
4703 if (bs
->drv
->bdrv_close
) {
4704 /* Must unfreeze all children, so bdrv_unref_child() works */
4705 bs
->drv
->bdrv_close(bs
);
4710 QLIST_FOREACH_SAFE(child
, &bs
->children
, next
, next
) {
4711 bdrv_unref_child(bs
, child
);
4718 qatomic_set(&bs
->copy_on_read
, 0);
4719 bs
->backing_file
[0] = '\0';
4720 bs
->backing_format
[0] = '\0';
4721 bs
->total_sectors
= 0;
4722 bs
->encrypted
= false;
4724 qobject_unref(bs
->options
);
4725 qobject_unref(bs
->explicit_options
);
4727 bs
->explicit_options
= NULL
;
4728 qobject_unref(bs
->full_open_options
);
4729 bs
->full_open_options
= NULL
;
4730 g_free(bs
->block_status_cache
);
4731 bs
->block_status_cache
= NULL
;
4733 bdrv_release_named_dirty_bitmaps(bs
);
4734 assert(QLIST_EMPTY(&bs
->dirty_bitmaps
));
4736 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_next
) {
4739 QLIST_INIT(&bs
->aio_notifiers
);
4740 bdrv_drained_end(bs
);
4743 * If we're still inside some bdrv_drain_all_begin()/end() sections, end
4744 * them now since this BDS won't exist anymore when bdrv_drain_all_end()
4747 if (bs
->quiesce_counter
) {
4748 bdrv_drain_all_end_quiesce(bs
);
4752 void bdrv_close_all(void)
4754 assert(job_next(NULL
) == NULL
);
4756 /* Drop references from requests still in flight, such as canceled block
4757 * jobs whose AIO context has not been polled yet */
4760 blk_remove_all_bs();
4761 blockdev_close_all_bdrv_states();
4763 assert(QTAILQ_EMPTY(&all_bdrv_states
));
4766 static bool should_update_child(BdrvChild
*c
, BlockDriverState
*to
)
4772 if (c
->klass
->stay_at_node
) {
4776 /* If the child @c belongs to the BDS @to, replacing the current
4777 * c->bs by @to would mean to create a loop.
4779 * Such a case occurs when appending a BDS to a backing chain.
4780 * For instance, imagine the following chain:
4782 * guest device -> node A -> further backing chain...
4784 * Now we create a new BDS B which we want to put on top of this
4785 * chain, so we first attach A as its backing node:
4790 * guest device -> node A -> further backing chain...
4792 * Finally we want to replace A by B. When doing that, we want to
4793 * replace all pointers to A by pointers to B -- except for the
4794 * pointer from B because (1) that would create a loop, and (2)
4795 * that pointer should simply stay intact:
4797 * guest device -> node B
4800 * node A -> further backing chain...
4802 * In general, when replacing a node A (c->bs) by a node B (@to),
4803 * if A is a child of B, that means we cannot replace A by B there
4804 * because that would create a loop. Silently detaching A from B
4805 * is also not really an option. So overall just leaving A in
4806 * place there is the most sensible choice.
4808 * We would also create a loop in any cases where @c is only
4809 * indirectly referenced by @to. Prevent this by returning false
4810 * if @c is found (by breadth-first search) anywhere in the whole
4815 found
= g_hash_table_new(NULL
, NULL
);
4816 g_hash_table_add(found
, to
);
4817 queue
= g_queue_new();
4818 g_queue_push_tail(queue
, to
);
4820 while (!g_queue_is_empty(queue
)) {
4821 BlockDriverState
*v
= g_queue_pop_head(queue
);
4824 QLIST_FOREACH(c2
, &v
->children
, next
) {
4830 if (g_hash_table_contains(found
, c2
->bs
)) {
4834 g_queue_push_tail(queue
, c2
->bs
);
4835 g_hash_table_add(found
, c2
->bs
);
4839 g_queue_free(queue
);
4840 g_hash_table_destroy(found
);
4845 typedef struct BdrvRemoveFilterOrCowChild
{
4848 } BdrvRemoveFilterOrCowChild
;
4850 static void bdrv_remove_filter_or_cow_child_abort(void *opaque
)
4852 BdrvRemoveFilterOrCowChild
*s
= opaque
;
4853 BlockDriverState
*parent_bs
= s
->child
->opaque
;
4855 if (s
->is_backing
) {
4856 parent_bs
->backing
= s
->child
;
4858 parent_bs
->file
= s
->child
;
4862 * We don't have to restore child->bs here to undo bdrv_replace_child_tran()
4863 * because that function is transactionable and it registered own completion
4864 * entries in @tran, so .abort() for bdrv_replace_child_safe() will be
4865 * called automatically.
4869 static void bdrv_remove_filter_or_cow_child_commit(void *opaque
)
4871 BdrvRemoveFilterOrCowChild
*s
= opaque
;
4873 bdrv_child_free(s
->child
);
4876 static TransactionActionDrv bdrv_remove_filter_or_cow_child_drv
= {
4877 .abort
= bdrv_remove_filter_or_cow_child_abort
,
4878 .commit
= bdrv_remove_filter_or_cow_child_commit
,
4883 * A function to remove backing or file child of @bs.
4884 * Function doesn't update permissions, caller is responsible for this.
4886 static void bdrv_remove_file_or_backing_child(BlockDriverState
*bs
,
4890 BdrvRemoveFilterOrCowChild
*s
;
4892 assert(child
== bs
->backing
|| child
== bs
->file
);
4899 bdrv_replace_child_tran(child
, NULL
, tran
);
4902 s
= g_new(BdrvRemoveFilterOrCowChild
, 1);
4903 *s
= (BdrvRemoveFilterOrCowChild
) {
4905 .is_backing
= (child
== bs
->backing
),
4907 tran_add(tran
, &bdrv_remove_filter_or_cow_child_drv
, s
);
4909 if (s
->is_backing
) {
4917 * A function to remove backing-chain child of @bs if exists: cow child for
4918 * format nodes (always .backing) and filter child for filters (may be .file or
4921 static void bdrv_remove_filter_or_cow_child(BlockDriverState
*bs
,
4924 bdrv_remove_file_or_backing_child(bs
, bdrv_filter_or_cow_child(bs
), tran
);
4927 static int bdrv_replace_node_noperm(BlockDriverState
*from
,
4928 BlockDriverState
*to
,
4929 bool auto_skip
, Transaction
*tran
,
4932 BdrvChild
*c
, *next
;
4934 QLIST_FOREACH_SAFE(c
, &from
->parents
, next_parent
, next
) {
4935 assert(c
->bs
== from
);
4936 if (!should_update_child(c
, to
)) {
4940 error_setg(errp
, "Should not change '%s' link to '%s'",
4941 c
->name
, from
->node_name
);
4945 error_setg(errp
, "Cannot change '%s' link to '%s'",
4946 c
->name
, from
->node_name
);
4949 bdrv_replace_child_tran(c
, to
, tran
);
4956 * With auto_skip=true bdrv_replace_node_common skips updating from parents
4957 * if it creates a parent-child relation loop or if parent is block-job.
4959 * With auto_skip=false the error is returned if from has a parent which should
4962 * With @detach_subchain=true @to must be in a backing chain of @from. In this
4963 * case backing link of the cow-parent of @to is removed.
4965 static int bdrv_replace_node_common(BlockDriverState
*from
,
4966 BlockDriverState
*to
,
4967 bool auto_skip
, bool detach_subchain
,
4970 Transaction
*tran
= tran_new();
4971 g_autoptr(GHashTable
) found
= NULL
;
4972 g_autoptr(GSList
) refresh_list
= NULL
;
4973 BlockDriverState
*to_cow_parent
= NULL
;
4976 if (detach_subchain
) {
4977 assert(bdrv_chain_contains(from
, to
));
4979 for (to_cow_parent
= from
;
4980 bdrv_filter_or_cow_bs(to_cow_parent
) != to
;
4981 to_cow_parent
= bdrv_filter_or_cow_bs(to_cow_parent
))
4987 /* Make sure that @from doesn't go away until we have successfully attached
4988 * all of its parents to @to. */
4991 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
4992 assert(bdrv_get_aio_context(from
) == bdrv_get_aio_context(to
));
4993 bdrv_drained_begin(from
);
4996 * Do the replacement without permission update.
4997 * Replacement may influence the permissions, we should calculate new
4998 * permissions based on new graph. If we fail, we'll roll-back the
5001 ret
= bdrv_replace_node_noperm(from
, to
, auto_skip
, tran
, errp
);
5006 if (detach_subchain
) {
5007 bdrv_remove_filter_or_cow_child(to_cow_parent
, tran
);
5010 found
= g_hash_table_new(NULL
, NULL
);
5012 refresh_list
= bdrv_topological_dfs(refresh_list
, found
, to
);
5013 refresh_list
= bdrv_topological_dfs(refresh_list
, found
, from
);
5015 ret
= bdrv_list_refresh_perms(refresh_list
, NULL
, tran
, errp
);
5023 tran_finalize(tran
, ret
);
5025 bdrv_drained_end(from
);
5031 int bdrv_replace_node(BlockDriverState
*from
, BlockDriverState
*to
,
5034 return bdrv_replace_node_common(from
, to
, true, false, errp
);
5037 int bdrv_drop_filter(BlockDriverState
*bs
, Error
**errp
)
5039 return bdrv_replace_node_common(bs
, bdrv_filter_or_cow_bs(bs
), true, true,
5044 * Add new bs contents at the top of an image chain while the chain is
5045 * live, while keeping required fields on the top layer.
5047 * This will modify the BlockDriverState fields, and swap contents
5048 * between bs_new and bs_top. Both bs_new and bs_top are modified.
5050 * bs_new must not be attached to a BlockBackend and must not have backing
5053 * This function does not create any image files.
5055 int bdrv_append(BlockDriverState
*bs_new
, BlockDriverState
*bs_top
,
5059 Transaction
*tran
= tran_new();
5061 assert(!bs_new
->backing
);
5063 ret
= bdrv_attach_child_noperm(bs_new
, bs_top
, "backing",
5064 &child_of_bds
, bdrv_backing_role(bs_new
),
5065 &bs_new
->backing
, tran
, errp
);
5070 ret
= bdrv_replace_node_noperm(bs_top
, bs_new
, true, tran
, errp
);
5075 ret
= bdrv_refresh_perms(bs_new
, errp
);
5077 tran_finalize(tran
, ret
);
5079 bdrv_refresh_limits(bs_top
, NULL
, NULL
);
5084 /* Not for empty child */
5085 int bdrv_replace_child_bs(BdrvChild
*child
, BlockDriverState
*new_bs
,
5089 Transaction
*tran
= tran_new();
5090 g_autoptr(GHashTable
) found
= NULL
;
5091 g_autoptr(GSList
) refresh_list
= NULL
;
5092 BlockDriverState
*old_bs
= child
->bs
;
5095 bdrv_drained_begin(old_bs
);
5096 bdrv_drained_begin(new_bs
);
5098 bdrv_replace_child_tran(child
, new_bs
, tran
);
5100 found
= g_hash_table_new(NULL
, NULL
);
5101 refresh_list
= bdrv_topological_dfs(refresh_list
, found
, old_bs
);
5102 refresh_list
= bdrv_topological_dfs(refresh_list
, found
, new_bs
);
5104 ret
= bdrv_list_refresh_perms(refresh_list
, NULL
, tran
, errp
);
5106 tran_finalize(tran
, ret
);
5108 bdrv_drained_end(old_bs
);
5109 bdrv_drained_end(new_bs
);
5115 static void bdrv_delete(BlockDriverState
*bs
)
5117 assert(bdrv_op_blocker_is_empty(bs
));
5118 assert(!bs
->refcnt
);
5120 /* remove from list, if necessary */
5121 if (bs
->node_name
[0] != '\0') {
5122 QTAILQ_REMOVE(&graph_bdrv_states
, bs
, node_list
);
5124 QTAILQ_REMOVE(&all_bdrv_states
, bs
, bs_list
);
5133 * Replace @bs by newly created block node.
5135 * @options is a QDict of options to pass to the block drivers, or NULL for an
5136 * empty set of options. The reference to the QDict belongs to the block layer
5137 * after the call (even on failure), so if the caller intends to reuse the
5138 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
5140 BlockDriverState
*bdrv_insert_node(BlockDriverState
*bs
, QDict
*options
,
5141 int flags
, Error
**errp
)
5145 BlockDriverState
*new_node_bs
= NULL
;
5146 const char *drvname
, *node_name
;
5149 drvname
= qdict_get_try_str(options
, "driver");
5151 error_setg(errp
, "driver is not specified");
5155 drv
= bdrv_find_format(drvname
);
5157 error_setg(errp
, "Unknown driver: '%s'", drvname
);
5161 node_name
= qdict_get_try_str(options
, "node-name");
5163 new_node_bs
= bdrv_new_open_driver_opts(drv
, node_name
, options
, flags
,
5165 options
= NULL
; /* bdrv_new_open_driver() eats options */
5167 error_prepend(errp
, "Could not create node: ");
5171 bdrv_drained_begin(bs
);
5172 ret
= bdrv_replace_node(bs
, new_node_bs
, errp
);
5173 bdrv_drained_end(bs
);
5176 error_prepend(errp
, "Could not replace node: ");
5183 qobject_unref(options
);
5184 bdrv_unref(new_node_bs
);
5189 * Run consistency checks on an image
5191 * Returns 0 if the check could be completed (it doesn't mean that the image is
5192 * free of errors) or -errno when an internal error occurred. The results of the
5193 * check are stored in res.
5195 int coroutine_fn
bdrv_co_check(BlockDriverState
*bs
,
5196 BdrvCheckResult
*res
, BdrvCheckMode fix
)
5198 if (bs
->drv
== NULL
) {
5201 if (bs
->drv
->bdrv_co_check
== NULL
) {
5205 memset(res
, 0, sizeof(*res
));
5206 return bs
->drv
->bdrv_co_check(bs
, res
, fix
);
5212 * -EINVAL - backing format specified, but no file
5213 * -ENOSPC - can't update the backing file because no space is left in the
5215 * -ENOTSUP - format driver doesn't support changing the backing file
5217 int bdrv_change_backing_file(BlockDriverState
*bs
, const char *backing_file
,
5218 const char *backing_fmt
, bool require
)
5220 BlockDriver
*drv
= bs
->drv
;
5227 /* Backing file format doesn't make sense without a backing file */
5228 if (backing_fmt
&& !backing_file
) {
5232 if (require
&& backing_file
&& !backing_fmt
) {
5236 if (drv
->bdrv_change_backing_file
!= NULL
) {
5237 ret
= drv
->bdrv_change_backing_file(bs
, backing_file
, backing_fmt
);
5243 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
), backing_file
?: "");
5244 pstrcpy(bs
->backing_format
, sizeof(bs
->backing_format
), backing_fmt
?: "");
5245 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
5246 backing_file
?: "");
5252 * Finds the first non-filter node above bs in the chain between
5253 * active and bs. The returned node is either an immediate parent of
5254 * bs, or there are only filter nodes between the two.
5256 * Returns NULL if bs is not found in active's image chain,
5257 * or if active == bs.
5259 * Returns the bottommost base image if bs == NULL.
5261 BlockDriverState
*bdrv_find_overlay(BlockDriverState
*active
,
5262 BlockDriverState
*bs
)
5264 bs
= bdrv_skip_filters(bs
);
5265 active
= bdrv_skip_filters(active
);
5268 BlockDriverState
*next
= bdrv_backing_chain_next(active
);
5278 /* Given a BDS, searches for the base layer. */
5279 BlockDriverState
*bdrv_find_base(BlockDriverState
*bs
)
5281 return bdrv_find_overlay(bs
, NULL
);
5285 * Return true if at least one of the COW (backing) and filter links
5286 * between @bs and @base is frozen. @errp is set if that's the case.
5287 * @base must be reachable from @bs, or NULL.
5289 bool bdrv_is_backing_chain_frozen(BlockDriverState
*bs
, BlockDriverState
*base
,
5292 BlockDriverState
*i
;
5295 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5296 child
= bdrv_filter_or_cow_child(i
);
5298 if (child
&& child
->frozen
) {
5299 error_setg(errp
, "Cannot change '%s' link from '%s' to '%s'",
5300 child
->name
, i
->node_name
, child
->bs
->node_name
);
5309 * Freeze all COW (backing) and filter links between @bs and @base.
5310 * If any of the links is already frozen the operation is aborted and
5311 * none of the links are modified.
5312 * @base must be reachable from @bs, or NULL.
5313 * Returns 0 on success. On failure returns < 0 and sets @errp.
5315 int bdrv_freeze_backing_chain(BlockDriverState
*bs
, BlockDriverState
*base
,
5318 BlockDriverState
*i
;
5321 if (bdrv_is_backing_chain_frozen(bs
, base
, errp
)) {
5325 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5326 child
= bdrv_filter_or_cow_child(i
);
5327 if (child
&& child
->bs
->never_freeze
) {
5328 error_setg(errp
, "Cannot freeze '%s' link to '%s'",
5329 child
->name
, child
->bs
->node_name
);
5334 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5335 child
= bdrv_filter_or_cow_child(i
);
5337 child
->frozen
= true;
5345 * Unfreeze all COW (backing) and filter links between @bs and @base.
5346 * The caller must ensure that all links are frozen before using this
5348 * @base must be reachable from @bs, or NULL.
5350 void bdrv_unfreeze_backing_chain(BlockDriverState
*bs
, BlockDriverState
*base
)
5352 BlockDriverState
*i
;
5355 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5356 child
= bdrv_filter_or_cow_child(i
);
5358 assert(child
->frozen
);
5359 child
->frozen
= false;
5365 * Drops images above 'base' up to and including 'top', and sets the image
5366 * above 'top' to have base as its backing file.
5368 * Requires that the overlay to 'top' is opened r/w, so that the backing file
5369 * information in 'bs' can be properly updated.
5371 * E.g., this will convert the following chain:
5372 * bottom <- base <- intermediate <- top <- active
5376 * bottom <- base <- active
5378 * It is allowed for bottom==base, in which case it converts:
5380 * base <- intermediate <- top <- active
5386 * If backing_file_str is non-NULL, it will be used when modifying top's
5387 * overlay image metadata.
5390 * if active == top, that is considered an error
5393 int bdrv_drop_intermediate(BlockDriverState
*top
, BlockDriverState
*base
,
5394 const char *backing_file_str
)
5396 BlockDriverState
*explicit_top
= top
;
5397 bool update_inherits_from
;
5399 Error
*local_err
= NULL
;
5401 g_autoptr(GSList
) updated_children
= NULL
;
5405 bdrv_subtree_drained_begin(top
);
5407 if (!top
->drv
|| !base
->drv
) {
5411 /* Make sure that base is in the backing chain of top */
5412 if (!bdrv_chain_contains(top
, base
)) {
5416 /* If 'base' recursively inherits from 'top' then we should set
5417 * base->inherits_from to top->inherits_from after 'top' and all
5418 * other intermediate nodes have been dropped.
5419 * If 'top' is an implicit node (e.g. "commit_top") we should skip
5420 * it because no one inherits from it. We use explicit_top for that. */
5421 explicit_top
= bdrv_skip_implicit_filters(explicit_top
);
5422 update_inherits_from
= bdrv_inherits_from_recursive(base
, explicit_top
);
5424 /* success - we can delete the intermediate states, and link top->base */
5425 /* TODO Check graph modification op blockers (BLK_PERM_GRAPH_MOD) once
5426 * we've figured out how they should work. */
5427 if (!backing_file_str
) {
5428 bdrv_refresh_filename(base
);
5429 backing_file_str
= base
->filename
;
5432 QLIST_FOREACH(c
, &top
->parents
, next_parent
) {
5433 updated_children
= g_slist_prepend(updated_children
, c
);
5437 * It seems correct to pass detach_subchain=true here, but it triggers
5438 * one more yet not fixed bug, when due to nested aio_poll loop we switch to
5439 * another drained section, which modify the graph (for example, removing
5440 * the child, which we keep in updated_children list). So, it's a TODO.
5442 * Note, bug triggered if pass detach_subchain=true here and run
5443 * test-bdrv-drain. test_drop_intermediate_poll() test-case will crash.
5446 bdrv_replace_node_common(top
, base
, false, false, &local_err
);
5448 error_report_err(local_err
);
5452 for (p
= updated_children
; p
; p
= p
->next
) {
5455 if (c
->klass
->update_filename
) {
5456 ret
= c
->klass
->update_filename(c
, base
, backing_file_str
,
5460 * TODO: Actually, we want to rollback all previous iterations
5461 * of this loop, and (which is almost impossible) previous
5462 * bdrv_replace_node()...
5464 * Note, that c->klass->update_filename may lead to permission
5465 * update, so it's a bad idea to call it inside permission
5466 * update transaction of bdrv_replace_node.
5468 error_report_err(local_err
);
5474 if (update_inherits_from
) {
5475 base
->inherits_from
= explicit_top
->inherits_from
;
5480 bdrv_subtree_drained_end(top
);
5486 * Implementation of BlockDriver.bdrv_get_allocated_file_size() that
5487 * sums the size of all data-bearing children. (This excludes backing
5490 static int64_t bdrv_sum_allocated_file_size(BlockDriverState
*bs
)
5493 int64_t child_size
, sum
= 0;
5495 QLIST_FOREACH(child
, &bs
->children
, next
) {
5496 if (child
->role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
|
5497 BDRV_CHILD_FILTERED
))
5499 child_size
= bdrv_get_allocated_file_size(child
->bs
);
5500 if (child_size
< 0) {
5511 * Length of a allocated file in bytes. Sparse files are counted by actual
5512 * allocated space. Return < 0 if error or unknown.
5514 int64_t bdrv_get_allocated_file_size(BlockDriverState
*bs
)
5516 BlockDriver
*drv
= bs
->drv
;
5520 if (drv
->bdrv_get_allocated_file_size
) {
5521 return drv
->bdrv_get_allocated_file_size(bs
);
5524 if (drv
->bdrv_file_open
) {
5526 * Protocol drivers default to -ENOTSUP (most of their data is
5527 * not stored in any of their children (if they even have any),
5528 * so there is no generic way to figure it out).
5531 } else if (drv
->is_filter
) {
5532 /* Filter drivers default to the size of their filtered child */
5533 return bdrv_get_allocated_file_size(bdrv_filter_bs(bs
));
5535 /* Other drivers default to summing their children's sizes */
5536 return bdrv_sum_allocated_file_size(bs
);
5542 * @drv: Format driver
5543 * @opts: Creation options for new image
5544 * @in_bs: Existing image containing data for new image (may be NULL)
5545 * @errp: Error object
5546 * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo())
5549 * Calculate file size required to create a new image.
5551 * If @in_bs is given then space for allocated clusters and zero clusters
5552 * from that image are included in the calculation. If @opts contains a
5553 * backing file that is shared by @in_bs then backing clusters may be omitted
5554 * from the calculation.
5556 * If @in_bs is NULL then the calculation includes no allocated clusters
5557 * unless a preallocation option is given in @opts.
5559 * Note that @in_bs may use a different BlockDriver from @drv.
5561 * If an error occurs the @errp pointer is set.
5563 BlockMeasureInfo
*bdrv_measure(BlockDriver
*drv
, QemuOpts
*opts
,
5564 BlockDriverState
*in_bs
, Error
**errp
)
5566 if (!drv
->bdrv_measure
) {
5567 error_setg(errp
, "Block driver '%s' does not support size measurement",
5572 return drv
->bdrv_measure(opts
, in_bs
, errp
);
5576 * Return number of sectors on success, -errno on error.
5578 int64_t bdrv_nb_sectors(BlockDriverState
*bs
)
5580 BlockDriver
*drv
= bs
->drv
;
5585 if (drv
->has_variable_length
) {
5586 int ret
= refresh_total_sectors(bs
, bs
->total_sectors
);
5591 return bs
->total_sectors
;
5595 * Return length in bytes on success, -errno on error.
5596 * The length is always a multiple of BDRV_SECTOR_SIZE.
5598 int64_t bdrv_getlength(BlockDriverState
*bs
)
5600 int64_t ret
= bdrv_nb_sectors(bs
);
5605 if (ret
> INT64_MAX
/ BDRV_SECTOR_SIZE
) {
5608 return ret
* BDRV_SECTOR_SIZE
;
5611 /* return 0 as number of sectors if no device present or error */
5612 void bdrv_get_geometry(BlockDriverState
*bs
, uint64_t *nb_sectors_ptr
)
5614 int64_t nb_sectors
= bdrv_nb_sectors(bs
);
5616 *nb_sectors_ptr
= nb_sectors
< 0 ? 0 : nb_sectors
;
5619 bool bdrv_is_sg(BlockDriverState
*bs
)
5625 * Return whether the given node supports compressed writes.
5627 bool bdrv_supports_compressed_writes(BlockDriverState
*bs
)
5629 BlockDriverState
*filtered
;
5631 if (!bs
->drv
|| !block_driver_can_compress(bs
->drv
)) {
5635 filtered
= bdrv_filter_bs(bs
);
5638 * Filters can only forward compressed writes, so we have to
5641 return bdrv_supports_compressed_writes(filtered
);
5647 const char *bdrv_get_format_name(BlockDriverState
*bs
)
5649 return bs
->drv
? bs
->drv
->format_name
: NULL
;
5652 static int qsort_strcmp(const void *a
, const void *b
)
5654 return strcmp(*(char *const *)a
, *(char *const *)b
);
5657 void bdrv_iterate_format(void (*it
)(void *opaque
, const char *name
),
5658 void *opaque
, bool read_only
)
5663 const char **formats
= NULL
;
5665 QLIST_FOREACH(drv
, &bdrv_drivers
, list
) {
5666 if (drv
->format_name
) {
5670 if (use_bdrv_whitelist
&& !bdrv_is_whitelisted(drv
, read_only
)) {
5674 while (formats
&& i
&& !found
) {
5675 found
= !strcmp(formats
[--i
], drv
->format_name
);
5679 formats
= g_renew(const char *, formats
, count
+ 1);
5680 formats
[count
++] = drv
->format_name
;
5685 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); i
++) {
5686 const char *format_name
= block_driver_modules
[i
].format_name
;
5692 if (use_bdrv_whitelist
&&
5693 !bdrv_format_is_whitelisted(format_name
, read_only
)) {
5697 while (formats
&& j
&& !found
) {
5698 found
= !strcmp(formats
[--j
], format_name
);
5702 formats
= g_renew(const char *, formats
, count
+ 1);
5703 formats
[count
++] = format_name
;
5708 qsort(formats
, count
, sizeof(formats
[0]), qsort_strcmp
);
5710 for (i
= 0; i
< count
; i
++) {
5711 it(opaque
, formats
[i
]);
5717 /* This function is to find a node in the bs graph */
5718 BlockDriverState
*bdrv_find_node(const char *node_name
)
5720 BlockDriverState
*bs
;
5724 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
5725 if (!strcmp(node_name
, bs
->node_name
)) {
5732 /* Put this QMP function here so it can access the static graph_bdrv_states. */
5733 BlockDeviceInfoList
*bdrv_named_nodes_list(bool flat
,
5736 BlockDeviceInfoList
*list
;
5737 BlockDriverState
*bs
;
5740 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
5741 BlockDeviceInfo
*info
= bdrv_block_device_info(NULL
, bs
, flat
, errp
);
5743 qapi_free_BlockDeviceInfoList(list
);
5746 QAPI_LIST_PREPEND(list
, info
);
5752 typedef struct XDbgBlockGraphConstructor
{
5753 XDbgBlockGraph
*graph
;
5754 GHashTable
*graph_nodes
;
5755 } XDbgBlockGraphConstructor
;
5757 static XDbgBlockGraphConstructor
*xdbg_graph_new(void)
5759 XDbgBlockGraphConstructor
*gr
= g_new(XDbgBlockGraphConstructor
, 1);
5761 gr
->graph
= g_new0(XDbgBlockGraph
, 1);
5762 gr
->graph_nodes
= g_hash_table_new(NULL
, NULL
);
5767 static XDbgBlockGraph
*xdbg_graph_finalize(XDbgBlockGraphConstructor
*gr
)
5769 XDbgBlockGraph
*graph
= gr
->graph
;
5771 g_hash_table_destroy(gr
->graph_nodes
);
5777 static uintptr_t xdbg_graph_node_num(XDbgBlockGraphConstructor
*gr
, void *node
)
5779 uintptr_t ret
= (uintptr_t)g_hash_table_lookup(gr
->graph_nodes
, node
);
5786 * Start counting from 1, not 0, because 0 interferes with not-found (NULL)
5787 * answer of g_hash_table_lookup.
5789 ret
= g_hash_table_size(gr
->graph_nodes
) + 1;
5790 g_hash_table_insert(gr
->graph_nodes
, node
, (void *)ret
);
5795 static void xdbg_graph_add_node(XDbgBlockGraphConstructor
*gr
, void *node
,
5796 XDbgBlockGraphNodeType type
, const char *name
)
5798 XDbgBlockGraphNode
*n
;
5800 n
= g_new0(XDbgBlockGraphNode
, 1);
5802 n
->id
= xdbg_graph_node_num(gr
, node
);
5804 n
->name
= g_strdup(name
);
5806 QAPI_LIST_PREPEND(gr
->graph
->nodes
, n
);
5809 static void xdbg_graph_add_edge(XDbgBlockGraphConstructor
*gr
, void *parent
,
5810 const BdrvChild
*child
)
5812 BlockPermission qapi_perm
;
5813 XDbgBlockGraphEdge
*edge
;
5815 edge
= g_new0(XDbgBlockGraphEdge
, 1);
5817 edge
->parent
= xdbg_graph_node_num(gr
, parent
);
5818 edge
->child
= xdbg_graph_node_num(gr
, child
->bs
);
5819 edge
->name
= g_strdup(child
->name
);
5821 for (qapi_perm
= 0; qapi_perm
< BLOCK_PERMISSION__MAX
; qapi_perm
++) {
5822 uint64_t flag
= bdrv_qapi_perm_to_blk_perm(qapi_perm
);
5824 if (flag
& child
->perm
) {
5825 QAPI_LIST_PREPEND(edge
->perm
, qapi_perm
);
5827 if (flag
& child
->shared_perm
) {
5828 QAPI_LIST_PREPEND(edge
->shared_perm
, qapi_perm
);
5832 QAPI_LIST_PREPEND(gr
->graph
->edges
, edge
);
5836 XDbgBlockGraph
*bdrv_get_xdbg_block_graph(Error
**errp
)
5840 BlockDriverState
*bs
;
5842 XDbgBlockGraphConstructor
*gr
= xdbg_graph_new();
5844 for (blk
= blk_all_next(NULL
); blk
; blk
= blk_all_next(blk
)) {
5845 char *allocated_name
= NULL
;
5846 const char *name
= blk_name(blk
);
5849 name
= allocated_name
= blk_get_attached_dev_id(blk
);
5851 xdbg_graph_add_node(gr
, blk
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND
,
5853 g_free(allocated_name
);
5854 if (blk_root(blk
)) {
5855 xdbg_graph_add_edge(gr
, blk
, blk_root(blk
));
5859 for (job
= block_job_next(NULL
); job
; job
= block_job_next(job
)) {
5862 xdbg_graph_add_node(gr
, job
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB
,
5864 for (el
= job
->nodes
; el
; el
= el
->next
) {
5865 xdbg_graph_add_edge(gr
, job
, (BdrvChild
*)el
->data
);
5869 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
5870 xdbg_graph_add_node(gr
, bs
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_DRIVER
,
5872 QLIST_FOREACH(child
, &bs
->children
, next
) {
5873 xdbg_graph_add_edge(gr
, bs
, child
);
5877 return xdbg_graph_finalize(gr
);
5880 BlockDriverState
*bdrv_lookup_bs(const char *device
,
5881 const char *node_name
,
5885 BlockDriverState
*bs
;
5888 blk
= blk_by_name(device
);
5893 error_setg(errp
, "Device '%s' has no medium", device
);
5901 bs
= bdrv_find_node(node_name
);
5908 error_setg(errp
, "Cannot find device=\'%s\' nor node-name=\'%s\'",
5909 device
? device
: "",
5910 node_name
? node_name
: "");
5914 /* If 'base' is in the same chain as 'top', return true. Otherwise,
5915 * return false. If either argument is NULL, return false. */
5916 bool bdrv_chain_contains(BlockDriverState
*top
, BlockDriverState
*base
)
5918 while (top
&& top
!= base
) {
5919 top
= bdrv_filter_or_cow_bs(top
);
5925 BlockDriverState
*bdrv_next_node(BlockDriverState
*bs
)
5928 return QTAILQ_FIRST(&graph_bdrv_states
);
5930 return QTAILQ_NEXT(bs
, node_list
);
5933 BlockDriverState
*bdrv_next_all_states(BlockDriverState
*bs
)
5936 return QTAILQ_FIRST(&all_bdrv_states
);
5938 return QTAILQ_NEXT(bs
, bs_list
);
5941 const char *bdrv_get_node_name(const BlockDriverState
*bs
)
5943 return bs
->node_name
;
5946 const char *bdrv_get_parent_name(const BlockDriverState
*bs
)
5951 /* If multiple parents have a name, just pick the first one. */
5952 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
5953 if (c
->klass
->get_name
) {
5954 name
= c
->klass
->get_name(c
);
5955 if (name
&& *name
) {
5964 /* TODO check what callers really want: bs->node_name or blk_name() */
5965 const char *bdrv_get_device_name(const BlockDriverState
*bs
)
5967 return bdrv_get_parent_name(bs
) ?: "";
5970 /* This can be used to identify nodes that might not have a device
5971 * name associated. Since node and device names live in the same
5972 * namespace, the result is unambiguous. The exception is if both are
5973 * absent, then this returns an empty (non-null) string. */
5974 const char *bdrv_get_device_or_node_name(const BlockDriverState
*bs
)
5976 return bdrv_get_parent_name(bs
) ?: bs
->node_name
;
5979 int bdrv_get_flags(BlockDriverState
*bs
)
5981 return bs
->open_flags
;
5984 int bdrv_has_zero_init_1(BlockDriverState
*bs
)
5989 int bdrv_has_zero_init(BlockDriverState
*bs
)
5991 BlockDriverState
*filtered
;
5997 /* If BS is a copy on write image, it is initialized to
5998 the contents of the base image, which may not be zeroes. */
5999 if (bdrv_cow_child(bs
)) {
6002 if (bs
->drv
->bdrv_has_zero_init
) {
6003 return bs
->drv
->bdrv_has_zero_init(bs
);
6006 filtered
= bdrv_filter_bs(bs
);
6008 return bdrv_has_zero_init(filtered
);
6015 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState
*bs
)
6017 if (!(bs
->open_flags
& BDRV_O_UNMAP
)) {
6021 return bs
->supported_zero_flags
& BDRV_REQ_MAY_UNMAP
;
6024 void bdrv_get_backing_filename(BlockDriverState
*bs
,
6025 char *filename
, int filename_size
)
6027 pstrcpy(filename
, filename_size
, bs
->backing_file
);
6030 int bdrv_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
6033 BlockDriver
*drv
= bs
->drv
;
6034 /* if bs->drv == NULL, bs is closed, so there's nothing to do here */
6038 if (!drv
->bdrv_get_info
) {
6039 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
6041 return bdrv_get_info(filtered
, bdi
);
6045 memset(bdi
, 0, sizeof(*bdi
));
6046 ret
= drv
->bdrv_get_info(bs
, bdi
);
6051 if (bdi
->cluster_size
> BDRV_MAX_ALIGNMENT
) {
6058 ImageInfoSpecific
*bdrv_get_specific_info(BlockDriverState
*bs
,
6061 BlockDriver
*drv
= bs
->drv
;
6062 if (drv
&& drv
->bdrv_get_specific_info
) {
6063 return drv
->bdrv_get_specific_info(bs
, errp
);
6068 BlockStatsSpecific
*bdrv_get_specific_stats(BlockDriverState
*bs
)
6070 BlockDriver
*drv
= bs
->drv
;
6071 if (!drv
|| !drv
->bdrv_get_specific_stats
) {
6074 return drv
->bdrv_get_specific_stats(bs
);
6077 void bdrv_debug_event(BlockDriverState
*bs
, BlkdebugEvent event
)
6079 if (!bs
|| !bs
->drv
|| !bs
->drv
->bdrv_debug_event
) {
6083 bs
->drv
->bdrv_debug_event(bs
, event
);
6086 static BlockDriverState
*bdrv_find_debug_node(BlockDriverState
*bs
)
6088 while (bs
&& bs
->drv
&& !bs
->drv
->bdrv_debug_breakpoint
) {
6089 bs
= bdrv_primary_bs(bs
);
6092 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_breakpoint
) {
6093 assert(bs
->drv
->bdrv_debug_remove_breakpoint
);
6100 int bdrv_debug_breakpoint(BlockDriverState
*bs
, const char *event
,
6103 bs
= bdrv_find_debug_node(bs
);
6105 return bs
->drv
->bdrv_debug_breakpoint(bs
, event
, tag
);
6111 int bdrv_debug_remove_breakpoint(BlockDriverState
*bs
, const char *tag
)
6113 bs
= bdrv_find_debug_node(bs
);
6115 return bs
->drv
->bdrv_debug_remove_breakpoint(bs
, tag
);
6121 int bdrv_debug_resume(BlockDriverState
*bs
, const char *tag
)
6123 while (bs
&& (!bs
->drv
|| !bs
->drv
->bdrv_debug_resume
)) {
6124 bs
= bdrv_primary_bs(bs
);
6127 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_resume
) {
6128 return bs
->drv
->bdrv_debug_resume(bs
, tag
);
6134 bool bdrv_debug_is_suspended(BlockDriverState
*bs
, const char *tag
)
6136 while (bs
&& bs
->drv
&& !bs
->drv
->bdrv_debug_is_suspended
) {
6137 bs
= bdrv_primary_bs(bs
);
6140 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_is_suspended
) {
6141 return bs
->drv
->bdrv_debug_is_suspended(bs
, tag
);
6147 /* backing_file can either be relative, or absolute, or a protocol. If it is
6148 * relative, it must be relative to the chain. So, passing in bs->filename
6149 * from a BDS as backing_file should not be done, as that may be relative to
6150 * the CWD rather than the chain. */
6151 BlockDriverState
*bdrv_find_backing_image(BlockDriverState
*bs
,
6152 const char *backing_file
)
6154 char *filename_full
= NULL
;
6155 char *backing_file_full
= NULL
;
6156 char *filename_tmp
= NULL
;
6157 int is_protocol
= 0;
6158 bool filenames_refreshed
= false;
6159 BlockDriverState
*curr_bs
= NULL
;
6160 BlockDriverState
*retval
= NULL
;
6161 BlockDriverState
*bs_below
;
6163 if (!bs
|| !bs
->drv
|| !backing_file
) {
6167 filename_full
= g_malloc(PATH_MAX
);
6168 backing_file_full
= g_malloc(PATH_MAX
);
6170 is_protocol
= path_has_protocol(backing_file
);
6173 * Being largely a legacy function, skip any filters here
6174 * (because filters do not have normal filenames, so they cannot
6175 * match anyway; and allowing json:{} filenames is a bit out of
6178 for (curr_bs
= bdrv_skip_filters(bs
);
6179 bdrv_cow_child(curr_bs
) != NULL
;
6182 bs_below
= bdrv_backing_chain_next(curr_bs
);
6184 if (bdrv_backing_overridden(curr_bs
)) {
6186 * If the backing file was overridden, we can only compare
6187 * directly against the backing node's filename.
6190 if (!filenames_refreshed
) {
6192 * This will automatically refresh all of the
6193 * filenames in the rest of the backing chain, so we
6194 * only need to do this once.
6196 bdrv_refresh_filename(bs_below
);
6197 filenames_refreshed
= true;
6200 if (strcmp(backing_file
, bs_below
->filename
) == 0) {
6204 } else if (is_protocol
|| path_has_protocol(curr_bs
->backing_file
)) {
6206 * If either of the filename paths is actually a protocol, then
6207 * compare unmodified paths; otherwise make paths relative.
6209 char *backing_file_full_ret
;
6211 if (strcmp(backing_file
, curr_bs
->backing_file
) == 0) {
6215 /* Also check against the full backing filename for the image */
6216 backing_file_full_ret
= bdrv_get_full_backing_filename(curr_bs
,
6218 if (backing_file_full_ret
) {
6219 bool equal
= strcmp(backing_file
, backing_file_full_ret
) == 0;
6220 g_free(backing_file_full_ret
);
6227 /* If not an absolute filename path, make it relative to the current
6228 * image's filename path */
6229 filename_tmp
= bdrv_make_absolute_filename(curr_bs
, backing_file
,
6231 /* We are going to compare canonicalized absolute pathnames */
6232 if (!filename_tmp
|| !realpath(filename_tmp
, filename_full
)) {
6233 g_free(filename_tmp
);
6236 g_free(filename_tmp
);
6238 /* We need to make sure the backing filename we are comparing against
6239 * is relative to the current image filename (or absolute) */
6240 filename_tmp
= bdrv_get_full_backing_filename(curr_bs
, NULL
);
6241 if (!filename_tmp
|| !realpath(filename_tmp
, backing_file_full
)) {
6242 g_free(filename_tmp
);
6245 g_free(filename_tmp
);
6247 if (strcmp(backing_file_full
, filename_full
) == 0) {
6254 g_free(filename_full
);
6255 g_free(backing_file_full
);
6259 void bdrv_init(void)
6261 #ifdef CONFIG_BDRV_WHITELIST_TOOLS
6262 use_bdrv_whitelist
= 1;
6264 module_call_init(MODULE_INIT_BLOCK
);
6267 void bdrv_init_with_whitelist(void)
6269 use_bdrv_whitelist
= 1;
6273 int coroutine_fn
bdrv_co_invalidate_cache(BlockDriverState
*bs
, Error
**errp
)
6275 BdrvChild
*child
, *parent
;
6276 Error
*local_err
= NULL
;
6278 BdrvDirtyBitmap
*bm
;
6284 QLIST_FOREACH(child
, &bs
->children
, next
) {
6285 bdrv_co_invalidate_cache(child
->bs
, &local_err
);
6287 error_propagate(errp
, local_err
);
6293 * Update permissions, they may differ for inactive nodes.
6295 * Note that the required permissions of inactive images are always a
6296 * subset of the permissions required after activating the image. This
6297 * allows us to just get the permissions upfront without restricting
6298 * drv->bdrv_invalidate_cache().
6300 * It also means that in error cases, we don't have to try and revert to
6301 * the old permissions (which is an operation that could fail, too). We can
6302 * just keep the extended permissions for the next time that an activation
6303 * of the image is tried.
6305 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
6306 bs
->open_flags
&= ~BDRV_O_INACTIVE
;
6307 ret
= bdrv_refresh_perms(bs
, errp
);
6309 bs
->open_flags
|= BDRV_O_INACTIVE
;
6313 if (bs
->drv
->bdrv_co_invalidate_cache
) {
6314 bs
->drv
->bdrv_co_invalidate_cache(bs
, &local_err
);
6316 bs
->open_flags
|= BDRV_O_INACTIVE
;
6317 error_propagate(errp
, local_err
);
6322 FOR_EACH_DIRTY_BITMAP(bs
, bm
) {
6323 bdrv_dirty_bitmap_skip_store(bm
, false);
6326 ret
= refresh_total_sectors(bs
, bs
->total_sectors
);
6328 bs
->open_flags
|= BDRV_O_INACTIVE
;
6329 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
6334 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6335 if (parent
->klass
->activate
) {
6336 parent
->klass
->activate(parent
, &local_err
);
6338 bs
->open_flags
|= BDRV_O_INACTIVE
;
6339 error_propagate(errp
, local_err
);
6348 void bdrv_invalidate_cache_all(Error
**errp
)
6350 BlockDriverState
*bs
;
6351 BdrvNextIterator it
;
6353 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
6354 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
6357 aio_context_acquire(aio_context
);
6358 ret
= bdrv_invalidate_cache(bs
, errp
);
6359 aio_context_release(aio_context
);
6361 bdrv_next_cleanup(&it
);
6367 static bool bdrv_has_bds_parent(BlockDriverState
*bs
, bool only_active
)
6371 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6372 if (parent
->klass
->parent_is_bds
) {
6373 BlockDriverState
*parent_bs
= parent
->opaque
;
6374 if (!only_active
|| !(parent_bs
->open_flags
& BDRV_O_INACTIVE
)) {
6383 static int bdrv_inactivate_recurse(BlockDriverState
*bs
)
6385 BdrvChild
*child
, *parent
;
6387 uint64_t cumulative_perms
, cumulative_shared_perms
;
6393 /* Make sure that we don't inactivate a child before its parent.
6394 * It will be covered by recursion from the yet active parent. */
6395 if (bdrv_has_bds_parent(bs
, true)) {
6399 assert(!(bs
->open_flags
& BDRV_O_INACTIVE
));
6401 /* Inactivate this node */
6402 if (bs
->drv
->bdrv_inactivate
) {
6403 ret
= bs
->drv
->bdrv_inactivate(bs
);
6409 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6410 if (parent
->klass
->inactivate
) {
6411 ret
= parent
->klass
->inactivate(parent
);
6418 bdrv_get_cumulative_perm(bs
, &cumulative_perms
,
6419 &cumulative_shared_perms
);
6420 if (cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) {
6421 /* Our inactive parents still need write access. Inactivation failed. */
6425 bs
->open_flags
|= BDRV_O_INACTIVE
;
6428 * Update permissions, they may differ for inactive nodes.
6429 * We only tried to loosen restrictions, so errors are not fatal, ignore
6432 bdrv_refresh_perms(bs
, NULL
);
6434 /* Recursively inactivate children */
6435 QLIST_FOREACH(child
, &bs
->children
, next
) {
6436 ret
= bdrv_inactivate_recurse(child
->bs
);
6445 int bdrv_inactivate_all(void)
6447 BlockDriverState
*bs
= NULL
;
6448 BdrvNextIterator it
;
6450 GSList
*aio_ctxs
= NULL
, *ctx
;
6452 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
6453 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
6455 if (!g_slist_find(aio_ctxs
, aio_context
)) {
6456 aio_ctxs
= g_slist_prepend(aio_ctxs
, aio_context
);
6457 aio_context_acquire(aio_context
);
6461 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
6462 /* Nodes with BDS parents are covered by recursion from the last
6463 * parent that gets inactivated. Don't inactivate them a second
6464 * time if that has already happened. */
6465 if (bdrv_has_bds_parent(bs
, false)) {
6468 ret
= bdrv_inactivate_recurse(bs
);
6470 bdrv_next_cleanup(&it
);
6476 for (ctx
= aio_ctxs
; ctx
!= NULL
; ctx
= ctx
->next
) {
6477 AioContext
*aio_context
= ctx
->data
;
6478 aio_context_release(aio_context
);
6480 g_slist_free(aio_ctxs
);
6485 /**************************************************************/
6486 /* removable device support */
6489 * Return TRUE if the media is present
6491 bool bdrv_is_inserted(BlockDriverState
*bs
)
6493 BlockDriver
*drv
= bs
->drv
;
6499 if (drv
->bdrv_is_inserted
) {
6500 return drv
->bdrv_is_inserted(bs
);
6502 QLIST_FOREACH(child
, &bs
->children
, next
) {
6503 if (!bdrv_is_inserted(child
->bs
)) {
6511 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
6513 void bdrv_eject(BlockDriverState
*bs
, bool eject_flag
)
6515 BlockDriver
*drv
= bs
->drv
;
6517 if (drv
&& drv
->bdrv_eject
) {
6518 drv
->bdrv_eject(bs
, eject_flag
);
6523 * Lock or unlock the media (if it is locked, the user won't be able
6524 * to eject it manually).
6526 void bdrv_lock_medium(BlockDriverState
*bs
, bool locked
)
6528 BlockDriver
*drv
= bs
->drv
;
6530 trace_bdrv_lock_medium(bs
, locked
);
6532 if (drv
&& drv
->bdrv_lock_medium
) {
6533 drv
->bdrv_lock_medium(bs
, locked
);
6537 /* Get a reference to bs */
6538 void bdrv_ref(BlockDriverState
*bs
)
6543 /* Release a previously grabbed reference to bs.
6544 * If after releasing, reference count is zero, the BlockDriverState is
6546 void bdrv_unref(BlockDriverState
*bs
)
6551 assert(bs
->refcnt
> 0);
6552 if (--bs
->refcnt
== 0) {
6557 struct BdrvOpBlocker
{
6559 QLIST_ENTRY(BdrvOpBlocker
) list
;
6562 bool bdrv_op_is_blocked(BlockDriverState
*bs
, BlockOpType op
, Error
**errp
)
6564 BdrvOpBlocker
*blocker
;
6565 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
6566 if (!QLIST_EMPTY(&bs
->op_blockers
[op
])) {
6567 blocker
= QLIST_FIRST(&bs
->op_blockers
[op
]);
6568 error_propagate_prepend(errp
, error_copy(blocker
->reason
),
6569 "Node '%s' is busy: ",
6570 bdrv_get_device_or_node_name(bs
));
6576 void bdrv_op_block(BlockDriverState
*bs
, BlockOpType op
, Error
*reason
)
6578 BdrvOpBlocker
*blocker
;
6579 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
6581 blocker
= g_new0(BdrvOpBlocker
, 1);
6582 blocker
->reason
= reason
;
6583 QLIST_INSERT_HEAD(&bs
->op_blockers
[op
], blocker
, list
);
6586 void bdrv_op_unblock(BlockDriverState
*bs
, BlockOpType op
, Error
*reason
)
6588 BdrvOpBlocker
*blocker
, *next
;
6589 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
6590 QLIST_FOREACH_SAFE(blocker
, &bs
->op_blockers
[op
], list
, next
) {
6591 if (blocker
->reason
== reason
) {
6592 QLIST_REMOVE(blocker
, list
);
6598 void bdrv_op_block_all(BlockDriverState
*bs
, Error
*reason
)
6601 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
6602 bdrv_op_block(bs
, i
, reason
);
6606 void bdrv_op_unblock_all(BlockDriverState
*bs
, Error
*reason
)
6609 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
6610 bdrv_op_unblock(bs
, i
, reason
);
6614 bool bdrv_op_blocker_is_empty(BlockDriverState
*bs
)
6618 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
6619 if (!QLIST_EMPTY(&bs
->op_blockers
[i
])) {
6626 void bdrv_img_create(const char *filename
, const char *fmt
,
6627 const char *base_filename
, const char *base_fmt
,
6628 char *options
, uint64_t img_size
, int flags
, bool quiet
,
6631 QemuOptsList
*create_opts
= NULL
;
6632 QemuOpts
*opts
= NULL
;
6633 const char *backing_fmt
, *backing_file
;
6635 BlockDriver
*drv
, *proto_drv
;
6636 Error
*local_err
= NULL
;
6639 /* Find driver and parse its options */
6640 drv
= bdrv_find_format(fmt
);
6642 error_setg(errp
, "Unknown file format '%s'", fmt
);
6646 proto_drv
= bdrv_find_protocol(filename
, true, errp
);
6651 if (!drv
->create_opts
) {
6652 error_setg(errp
, "Format driver '%s' does not support image creation",
6657 if (!proto_drv
->create_opts
) {
6658 error_setg(errp
, "Protocol driver '%s' does not support image creation",
6659 proto_drv
->format_name
);
6663 /* Create parameter list */
6664 create_opts
= qemu_opts_append(create_opts
, drv
->create_opts
);
6665 create_opts
= qemu_opts_append(create_opts
, proto_drv
->create_opts
);
6667 opts
= qemu_opts_create(create_opts
, NULL
, 0, &error_abort
);
6669 /* Parse -o options */
6671 if (!qemu_opts_do_parse(opts
, options
, NULL
, errp
)) {
6676 if (!qemu_opt_get(opts
, BLOCK_OPT_SIZE
)) {
6677 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, img_size
, &error_abort
);
6678 } else if (img_size
!= UINT64_C(-1)) {
6679 error_setg(errp
, "The image size must be specified only once");
6683 if (base_filename
) {
6684 if (!qemu_opt_set(opts
, BLOCK_OPT_BACKING_FILE
, base_filename
,
6686 error_setg(errp
, "Backing file not supported for file format '%s'",
6693 if (!qemu_opt_set(opts
, BLOCK_OPT_BACKING_FMT
, base_fmt
, NULL
)) {
6694 error_setg(errp
, "Backing file format not supported for file "
6695 "format '%s'", fmt
);
6700 backing_file
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FILE
);
6702 if (!strcmp(filename
, backing_file
)) {
6703 error_setg(errp
, "Error: Trying to create an image with the "
6704 "same filename as the backing file");
6707 if (backing_file
[0] == '\0') {
6708 error_setg(errp
, "Expected backing file name, got empty string");
6713 backing_fmt
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FMT
);
6715 /* The size for the image must always be specified, unless we have a backing
6716 * file and we have not been forbidden from opening it. */
6717 size
= qemu_opt_get_size(opts
, BLOCK_OPT_SIZE
, img_size
);
6718 if (backing_file
&& !(flags
& BDRV_O_NO_BACKING
)) {
6719 BlockDriverState
*bs
;
6722 QDict
*backing_options
= NULL
;
6725 bdrv_get_full_backing_filename_from_filename(filename
, backing_file
,
6730 assert(full_backing
);
6733 * No need to do I/O here, which allows us to open encrypted
6734 * backing images without needing the secret
6737 back_flags
&= ~(BDRV_O_RDWR
| BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
);
6738 back_flags
|= BDRV_O_NO_IO
;
6740 backing_options
= qdict_new();
6742 qdict_put_str(backing_options
, "driver", backing_fmt
);
6744 qdict_put_bool(backing_options
, BDRV_OPT_FORCE_SHARE
, true);
6746 bs
= bdrv_open(full_backing
, NULL
, backing_options
, back_flags
,
6748 g_free(full_backing
);
6750 error_append_hint(&local_err
, "Could not open backing image.\n");
6754 error_setg(&local_err
,
6755 "Backing file specified without backing format");
6756 error_append_hint(&local_err
, "Detected format of %s.",
6757 bs
->drv
->format_name
);
6761 /* Opened BS, have no size */
6762 size
= bdrv_getlength(bs
);
6764 error_setg_errno(errp
, -size
, "Could not get size of '%s'",
6769 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, size
, &error_abort
);
6773 /* (backing_file && !(flags & BDRV_O_NO_BACKING)) */
6774 } else if (backing_file
&& !backing_fmt
) {
6775 error_setg(&local_err
,
6776 "Backing file specified without backing format");
6781 error_setg(errp
, "Image creation needs a size parameter");
6786 printf("Formatting '%s', fmt=%s ", filename
, fmt
);
6787 qemu_opts_print(opts
, " ");
6792 ret
= bdrv_create(drv
, filename
, opts
, &local_err
);
6794 if (ret
== -EFBIG
) {
6795 /* This is generally a better message than whatever the driver would
6796 * deliver (especially because of the cluster_size_hint), since that
6797 * is most probably not much different from "image too large". */
6798 const char *cluster_size_hint
= "";
6799 if (qemu_opt_get_size(opts
, BLOCK_OPT_CLUSTER_SIZE
, 0)) {
6800 cluster_size_hint
= " (try using a larger cluster size)";
6802 error_setg(errp
, "The image size is too large for file format '%s'"
6803 "%s", fmt
, cluster_size_hint
);
6804 error_free(local_err
);
6809 qemu_opts_del(opts
);
6810 qemu_opts_free(create_opts
);
6811 error_propagate(errp
, local_err
);
6814 AioContext
*bdrv_get_aio_context(BlockDriverState
*bs
)
6816 return bs
? bs
->aio_context
: qemu_get_aio_context();
6819 AioContext
*coroutine_fn
bdrv_co_enter(BlockDriverState
*bs
)
6821 Coroutine
*self
= qemu_coroutine_self();
6822 AioContext
*old_ctx
= qemu_coroutine_get_aio_context(self
);
6823 AioContext
*new_ctx
;
6826 * Increase bs->in_flight to ensure that this operation is completed before
6827 * moving the node to a different AioContext. Read new_ctx only afterwards.
6829 bdrv_inc_in_flight(bs
);
6831 new_ctx
= bdrv_get_aio_context(bs
);
6832 aio_co_reschedule_self(new_ctx
);
6836 void coroutine_fn
bdrv_co_leave(BlockDriverState
*bs
, AioContext
*old_ctx
)
6838 aio_co_reschedule_self(old_ctx
);
6839 bdrv_dec_in_flight(bs
);
6842 void coroutine_fn
bdrv_co_lock(BlockDriverState
*bs
)
6844 AioContext
*ctx
= bdrv_get_aio_context(bs
);
6846 /* In the main thread, bs->aio_context won't change concurrently */
6847 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
6850 * We're in coroutine context, so we already hold the lock of the main
6851 * loop AioContext. Don't lock it twice to avoid deadlocks.
6853 assert(qemu_in_coroutine());
6854 if (ctx
!= qemu_get_aio_context()) {
6855 aio_context_acquire(ctx
);
6859 void coroutine_fn
bdrv_co_unlock(BlockDriverState
*bs
)
6861 AioContext
*ctx
= bdrv_get_aio_context(bs
);
6863 assert(qemu_in_coroutine());
6864 if (ctx
!= qemu_get_aio_context()) {
6865 aio_context_release(ctx
);
6869 void bdrv_coroutine_enter(BlockDriverState
*bs
, Coroutine
*co
)
6871 aio_co_enter(bdrv_get_aio_context(bs
), co
);
6874 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier
*ban
)
6876 QLIST_REMOVE(ban
, list
);
6880 static void bdrv_detach_aio_context(BlockDriverState
*bs
)
6882 BdrvAioNotifier
*baf
, *baf_tmp
;
6884 assert(!bs
->walking_aio_notifiers
);
6885 bs
->walking_aio_notifiers
= true;
6886 QLIST_FOREACH_SAFE(baf
, &bs
->aio_notifiers
, list
, baf_tmp
) {
6888 bdrv_do_remove_aio_context_notifier(baf
);
6890 baf
->detach_aio_context(baf
->opaque
);
6893 /* Never mind iterating again to check for ->deleted. bdrv_close() will
6894 * remove remaining aio notifiers if we aren't called again.
6896 bs
->walking_aio_notifiers
= false;
6898 if (bs
->drv
&& bs
->drv
->bdrv_detach_aio_context
) {
6899 bs
->drv
->bdrv_detach_aio_context(bs
);
6902 if (bs
->quiesce_counter
) {
6903 aio_enable_external(bs
->aio_context
);
6905 bs
->aio_context
= NULL
;
6908 static void bdrv_attach_aio_context(BlockDriverState
*bs
,
6909 AioContext
*new_context
)
6911 BdrvAioNotifier
*ban
, *ban_tmp
;
6913 if (bs
->quiesce_counter
) {
6914 aio_disable_external(new_context
);
6917 bs
->aio_context
= new_context
;
6919 if (bs
->drv
&& bs
->drv
->bdrv_attach_aio_context
) {
6920 bs
->drv
->bdrv_attach_aio_context(bs
, new_context
);
6923 assert(!bs
->walking_aio_notifiers
);
6924 bs
->walking_aio_notifiers
= true;
6925 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_tmp
) {
6927 bdrv_do_remove_aio_context_notifier(ban
);
6929 ban
->attached_aio_context(new_context
, ban
->opaque
);
6932 bs
->walking_aio_notifiers
= false;
6936 * Changes the AioContext used for fd handlers, timers, and BHs by this
6937 * BlockDriverState and all its children and parents.
6939 * Must be called from the main AioContext.
6941 * The caller must own the AioContext lock for the old AioContext of bs, but it
6942 * must not own the AioContext lock for new_context (unless new_context is the
6943 * same as the current context of bs).
6945 * @ignore will accumulate all visited BdrvChild object. The caller is
6946 * responsible for freeing the list afterwards.
6948 void bdrv_set_aio_context_ignore(BlockDriverState
*bs
,
6949 AioContext
*new_context
, GSList
**ignore
)
6951 AioContext
*old_context
= bdrv_get_aio_context(bs
);
6952 GSList
*children_to_process
= NULL
;
6953 GSList
*parents_to_process
= NULL
;
6955 BdrvChild
*child
, *parent
;
6957 g_assert(qemu_get_current_aio_context() == qemu_get_aio_context());
6959 if (old_context
== new_context
) {
6963 bdrv_drained_begin(bs
);
6965 QLIST_FOREACH(child
, &bs
->children
, next
) {
6966 if (g_slist_find(*ignore
, child
)) {
6969 *ignore
= g_slist_prepend(*ignore
, child
);
6970 children_to_process
= g_slist_prepend(children_to_process
, child
);
6973 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6974 if (g_slist_find(*ignore
, parent
)) {
6977 *ignore
= g_slist_prepend(*ignore
, parent
);
6978 parents_to_process
= g_slist_prepend(parents_to_process
, parent
);
6981 for (entry
= children_to_process
;
6983 entry
= g_slist_next(entry
)) {
6984 child
= entry
->data
;
6985 bdrv_set_aio_context_ignore(child
->bs
, new_context
, ignore
);
6987 g_slist_free(children_to_process
);
6989 for (entry
= parents_to_process
;
6991 entry
= g_slist_next(entry
)) {
6992 parent
= entry
->data
;
6993 assert(parent
->klass
->set_aio_ctx
);
6994 parent
->klass
->set_aio_ctx(parent
, new_context
, ignore
);
6996 g_slist_free(parents_to_process
);
6998 bdrv_detach_aio_context(bs
);
7000 /* Acquire the new context, if necessary */
7001 if (qemu_get_aio_context() != new_context
) {
7002 aio_context_acquire(new_context
);
7005 bdrv_attach_aio_context(bs
, new_context
);
7008 * If this function was recursively called from
7009 * bdrv_set_aio_context_ignore(), there may be nodes in the
7010 * subtree that have not yet been moved to the new AioContext.
7011 * Release the old one so bdrv_drained_end() can poll them.
7013 if (qemu_get_aio_context() != old_context
) {
7014 aio_context_release(old_context
);
7017 bdrv_drained_end(bs
);
7019 if (qemu_get_aio_context() != old_context
) {
7020 aio_context_acquire(old_context
);
7022 if (qemu_get_aio_context() != new_context
) {
7023 aio_context_release(new_context
);
7027 static bool bdrv_parent_can_set_aio_context(BdrvChild
*c
, AioContext
*ctx
,
7028 GSList
**ignore
, Error
**errp
)
7030 if (g_slist_find(*ignore
, c
)) {
7033 *ignore
= g_slist_prepend(*ignore
, c
);
7036 * A BdrvChildClass that doesn't handle AioContext changes cannot
7037 * tolerate any AioContext changes
7039 if (!c
->klass
->can_set_aio_ctx
) {
7040 char *user
= bdrv_child_user_desc(c
);
7041 error_setg(errp
, "Changing iothreads is not supported by %s", user
);
7045 if (!c
->klass
->can_set_aio_ctx(c
, ctx
, ignore
, errp
)) {
7046 assert(!errp
|| *errp
);
7052 bool bdrv_child_can_set_aio_context(BdrvChild
*c
, AioContext
*ctx
,
7053 GSList
**ignore
, Error
**errp
)
7055 if (g_slist_find(*ignore
, c
)) {
7058 *ignore
= g_slist_prepend(*ignore
, c
);
7059 return bdrv_can_set_aio_context(c
->bs
, ctx
, ignore
, errp
);
7062 /* @ignore will accumulate all visited BdrvChild object. The caller is
7063 * responsible for freeing the list afterwards. */
7064 bool bdrv_can_set_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
7065 GSList
**ignore
, Error
**errp
)
7069 if (bdrv_get_aio_context(bs
) == ctx
) {
7073 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
7074 if (!bdrv_parent_can_set_aio_context(c
, ctx
, ignore
, errp
)) {
7078 QLIST_FOREACH(c
, &bs
->children
, next
) {
7079 if (!bdrv_child_can_set_aio_context(c
, ctx
, ignore
, errp
)) {
7087 int bdrv_child_try_set_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
7088 BdrvChild
*ignore_child
, Error
**errp
)
7093 ignore
= ignore_child
? g_slist_prepend(NULL
, ignore_child
) : NULL
;
7094 ret
= bdrv_can_set_aio_context(bs
, ctx
, &ignore
, errp
);
7095 g_slist_free(ignore
);
7101 ignore
= ignore_child
? g_slist_prepend(NULL
, ignore_child
) : NULL
;
7102 bdrv_set_aio_context_ignore(bs
, ctx
, &ignore
);
7103 g_slist_free(ignore
);
7108 int bdrv_try_set_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
7111 return bdrv_child_try_set_aio_context(bs
, ctx
, NULL
, errp
);
7114 void bdrv_add_aio_context_notifier(BlockDriverState
*bs
,
7115 void (*attached_aio_context
)(AioContext
*new_context
, void *opaque
),
7116 void (*detach_aio_context
)(void *opaque
), void *opaque
)
7118 BdrvAioNotifier
*ban
= g_new(BdrvAioNotifier
, 1);
7119 *ban
= (BdrvAioNotifier
){
7120 .attached_aio_context
= attached_aio_context
,
7121 .detach_aio_context
= detach_aio_context
,
7125 QLIST_INSERT_HEAD(&bs
->aio_notifiers
, ban
, list
);
7128 void bdrv_remove_aio_context_notifier(BlockDriverState
*bs
,
7129 void (*attached_aio_context
)(AioContext
*,
7131 void (*detach_aio_context
)(void *),
7134 BdrvAioNotifier
*ban
, *ban_next
;
7136 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_next
) {
7137 if (ban
->attached_aio_context
== attached_aio_context
&&
7138 ban
->detach_aio_context
== detach_aio_context
&&
7139 ban
->opaque
== opaque
&&
7140 ban
->deleted
== false)
7142 if (bs
->walking_aio_notifiers
) {
7143 ban
->deleted
= true;
7145 bdrv_do_remove_aio_context_notifier(ban
);
7154 int bdrv_amend_options(BlockDriverState
*bs
, QemuOpts
*opts
,
7155 BlockDriverAmendStatusCB
*status_cb
, void *cb_opaque
,
7160 error_setg(errp
, "Node is ejected");
7163 if (!bs
->drv
->bdrv_amend_options
) {
7164 error_setg(errp
, "Block driver '%s' does not support option amendment",
7165 bs
->drv
->format_name
);
7168 return bs
->drv
->bdrv_amend_options(bs
, opts
, status_cb
,
7169 cb_opaque
, force
, errp
);
7173 * This function checks whether the given @to_replace is allowed to be
7174 * replaced by a node that always shows the same data as @bs. This is
7175 * used for example to verify whether the mirror job can replace
7176 * @to_replace by the target mirrored from @bs.
7177 * To be replaceable, @bs and @to_replace may either be guaranteed to
7178 * always show the same data (because they are only connected through
7179 * filters), or some driver may allow replacing one of its children
7180 * because it can guarantee that this child's data is not visible at
7181 * all (for example, for dissenting quorum children that have no other
7184 bool bdrv_recurse_can_replace(BlockDriverState
*bs
,
7185 BlockDriverState
*to_replace
)
7187 BlockDriverState
*filtered
;
7189 if (!bs
|| !bs
->drv
) {
7193 if (bs
== to_replace
) {
7197 /* See what the driver can do */
7198 if (bs
->drv
->bdrv_recurse_can_replace
) {
7199 return bs
->drv
->bdrv_recurse_can_replace(bs
, to_replace
);
7202 /* For filters without an own implementation, we can recurse on our own */
7203 filtered
= bdrv_filter_bs(bs
);
7205 return bdrv_recurse_can_replace(filtered
, to_replace
);
7213 * Check whether the given @node_name can be replaced by a node that
7214 * has the same data as @parent_bs. If so, return @node_name's BDS;
7217 * @node_name must be a (recursive) *child of @parent_bs (or this
7218 * function will return NULL).
7220 * The result (whether the node can be replaced or not) is only valid
7221 * for as long as no graph or permission changes occur.
7223 BlockDriverState
*check_to_replace_node(BlockDriverState
*parent_bs
,
7224 const char *node_name
, Error
**errp
)
7226 BlockDriverState
*to_replace_bs
= bdrv_find_node(node_name
);
7227 AioContext
*aio_context
;
7229 if (!to_replace_bs
) {
7230 error_setg(errp
, "Failed to find node with node-name='%s'", node_name
);
7234 aio_context
= bdrv_get_aio_context(to_replace_bs
);
7235 aio_context_acquire(aio_context
);
7237 if (bdrv_op_is_blocked(to_replace_bs
, BLOCK_OP_TYPE_REPLACE
, errp
)) {
7238 to_replace_bs
= NULL
;
7242 /* We don't want arbitrary node of the BDS chain to be replaced only the top
7243 * most non filter in order to prevent data corruption.
7244 * Another benefit is that this tests exclude backing files which are
7245 * blocked by the backing blockers.
7247 if (!bdrv_recurse_can_replace(parent_bs
, to_replace_bs
)) {
7248 error_setg(errp
, "Cannot replace '%s' by a node mirrored from '%s', "
7249 "because it cannot be guaranteed that doing so would not "
7250 "lead to an abrupt change of visible data",
7251 node_name
, parent_bs
->node_name
);
7252 to_replace_bs
= NULL
;
7257 aio_context_release(aio_context
);
7258 return to_replace_bs
;
7262 * Iterates through the list of runtime option keys that are said to
7263 * be "strong" for a BDS. An option is called "strong" if it changes
7264 * a BDS's data. For example, the null block driver's "size" and
7265 * "read-zeroes" options are strong, but its "latency-ns" option is
7268 * If a key returned by this function ends with a dot, all options
7269 * starting with that prefix are strong.
7271 static const char *const *strong_options(BlockDriverState
*bs
,
7272 const char *const *curopt
)
7274 static const char *const global_options
[] = {
7275 "driver", "filename", NULL
7279 return &global_options
[0];
7283 if (curopt
== &global_options
[ARRAY_SIZE(global_options
) - 1] && bs
->drv
) {
7284 curopt
= bs
->drv
->strong_runtime_opts
;
7287 return (curopt
&& *curopt
) ? curopt
: NULL
;
7291 * Copies all strong runtime options from bs->options to the given
7292 * QDict. The set of strong option keys is determined by invoking
7295 * Returns true iff any strong option was present in bs->options (and
7296 * thus copied to the target QDict) with the exception of "filename"
7297 * and "driver". The caller is expected to use this value to decide
7298 * whether the existence of strong options prevents the generation of
7301 static bool append_strong_runtime_options(QDict
*d
, BlockDriverState
*bs
)
7303 bool found_any
= false;
7304 const char *const *option_name
= NULL
;
7310 while ((option_name
= strong_options(bs
, option_name
))) {
7311 bool option_given
= false;
7313 assert(strlen(*option_name
) > 0);
7314 if ((*option_name
)[strlen(*option_name
) - 1] != '.') {
7315 QObject
*entry
= qdict_get(bs
->options
, *option_name
);
7320 qdict_put_obj(d
, *option_name
, qobject_ref(entry
));
7321 option_given
= true;
7323 const QDictEntry
*entry
;
7324 for (entry
= qdict_first(bs
->options
); entry
;
7325 entry
= qdict_next(bs
->options
, entry
))
7327 if (strstart(qdict_entry_key(entry
), *option_name
, NULL
)) {
7328 qdict_put_obj(d
, qdict_entry_key(entry
),
7329 qobject_ref(qdict_entry_value(entry
)));
7330 option_given
= true;
7335 /* While "driver" and "filename" need to be included in a JSON filename,
7336 * their existence does not prohibit generation of a plain filename. */
7337 if (!found_any
&& option_given
&&
7338 strcmp(*option_name
, "driver") && strcmp(*option_name
, "filename"))
7344 if (!qdict_haskey(d
, "driver")) {
7345 /* Drivers created with bdrv_new_open_driver() may not have a
7346 * @driver option. Add it here. */
7347 qdict_put_str(d
, "driver", bs
->drv
->format_name
);
7353 /* Note: This function may return false positives; it may return true
7354 * even if opening the backing file specified by bs's image header
7355 * would result in exactly bs->backing. */
7356 bool bdrv_backing_overridden(BlockDriverState
*bs
)
7359 return strcmp(bs
->auto_backing_file
,
7360 bs
->backing
->bs
->filename
);
7362 /* No backing BDS, so if the image header reports any backing
7363 * file, it must have been suppressed */
7364 return bs
->auto_backing_file
[0] != '\0';
7368 /* Updates the following BDS fields:
7369 * - exact_filename: A filename which may be used for opening a block device
7370 * which (mostly) equals the given BDS (even without any
7371 * other options; so reading and writing must return the same
7372 * results, but caching etc. may be different)
7373 * - full_open_options: Options which, when given when opening a block device
7374 * (without a filename), result in a BDS (mostly)
7375 * equalling the given one
7376 * - filename: If exact_filename is set, it is copied here. Otherwise,
7377 * full_open_options is converted to a JSON object, prefixed with
7378 * "json:" (for use through the JSON pseudo protocol) and put here.
7380 void bdrv_refresh_filename(BlockDriverState
*bs
)
7382 BlockDriver
*drv
= bs
->drv
;
7384 BlockDriverState
*primary_child_bs
;
7386 bool backing_overridden
;
7387 bool generate_json_filename
; /* Whether our default implementation should
7388 fill exact_filename (false) or not (true) */
7394 /* This BDS's file name may depend on any of its children's file names, so
7395 * refresh those first */
7396 QLIST_FOREACH(child
, &bs
->children
, next
) {
7397 bdrv_refresh_filename(child
->bs
);
7401 /* For implicit nodes, just copy everything from the single child */
7402 child
= QLIST_FIRST(&bs
->children
);
7403 assert(QLIST_NEXT(child
, next
) == NULL
);
7405 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
),
7406 child
->bs
->exact_filename
);
7407 pstrcpy(bs
->filename
, sizeof(bs
->filename
), child
->bs
->filename
);
7409 qobject_unref(bs
->full_open_options
);
7410 bs
->full_open_options
= qobject_ref(child
->bs
->full_open_options
);
7415 backing_overridden
= bdrv_backing_overridden(bs
);
7417 if (bs
->open_flags
& BDRV_O_NO_IO
) {
7418 /* Without I/O, the backing file does not change anything.
7419 * Therefore, in such a case (primarily qemu-img), we can
7420 * pretend the backing file has not been overridden even if
7421 * it technically has been. */
7422 backing_overridden
= false;
7425 /* Gather the options QDict */
7427 generate_json_filename
= append_strong_runtime_options(opts
, bs
);
7428 generate_json_filename
|= backing_overridden
;
7430 if (drv
->bdrv_gather_child_options
) {
7431 /* Some block drivers may not want to present all of their children's
7432 * options, or name them differently from BdrvChild.name */
7433 drv
->bdrv_gather_child_options(bs
, opts
, backing_overridden
);
7435 QLIST_FOREACH(child
, &bs
->children
, next
) {
7436 if (child
== bs
->backing
&& !backing_overridden
) {
7437 /* We can skip the backing BDS if it has not been overridden */
7441 qdict_put(opts
, child
->name
,
7442 qobject_ref(child
->bs
->full_open_options
));
7445 if (backing_overridden
&& !bs
->backing
) {
7446 /* Force no backing file */
7447 qdict_put_null(opts
, "backing");
7451 qobject_unref(bs
->full_open_options
);
7452 bs
->full_open_options
= opts
;
7454 primary_child_bs
= bdrv_primary_bs(bs
);
7456 if (drv
->bdrv_refresh_filename
) {
7457 /* Obsolete information is of no use here, so drop the old file name
7458 * information before refreshing it */
7459 bs
->exact_filename
[0] = '\0';
7461 drv
->bdrv_refresh_filename(bs
);
7462 } else if (primary_child_bs
) {
7464 * Try to reconstruct valid information from the underlying
7465 * file -- this only works for format nodes (filter nodes
7466 * cannot be probed and as such must be selected by the user
7467 * either through an options dict, or through a special
7468 * filename which the filter driver must construct in its
7469 * .bdrv_refresh_filename() implementation).
7472 bs
->exact_filename
[0] = '\0';
7475 * We can use the underlying file's filename if:
7476 * - it has a filename,
7477 * - the current BDS is not a filter,
7478 * - the file is a protocol BDS, and
7479 * - opening that file (as this BDS's format) will automatically create
7480 * the BDS tree we have right now, that is:
7481 * - the user did not significantly change this BDS's behavior with
7482 * some explicit (strong) options
7483 * - no non-file child of this BDS has been overridden by the user
7484 * Both of these conditions are represented by generate_json_filename.
7486 if (primary_child_bs
->exact_filename
[0] &&
7487 primary_child_bs
->drv
->bdrv_file_open
&&
7488 !drv
->is_filter
&& !generate_json_filename
)
7490 strcpy(bs
->exact_filename
, primary_child_bs
->exact_filename
);
7494 if (bs
->exact_filename
[0]) {
7495 pstrcpy(bs
->filename
, sizeof(bs
->filename
), bs
->exact_filename
);
7497 GString
*json
= qobject_to_json(QOBJECT(bs
->full_open_options
));
7498 if (snprintf(bs
->filename
, sizeof(bs
->filename
), "json:%s",
7499 json
->str
) >= sizeof(bs
->filename
)) {
7500 /* Give user a hint if we truncated things. */
7501 strcpy(bs
->filename
+ sizeof(bs
->filename
) - 4, "...");
7503 g_string_free(json
, true);
7507 char *bdrv_dirname(BlockDriverState
*bs
, Error
**errp
)
7509 BlockDriver
*drv
= bs
->drv
;
7510 BlockDriverState
*child_bs
;
7513 error_setg(errp
, "Node '%s' is ejected", bs
->node_name
);
7517 if (drv
->bdrv_dirname
) {
7518 return drv
->bdrv_dirname(bs
, errp
);
7521 child_bs
= bdrv_primary_bs(bs
);
7523 return bdrv_dirname(child_bs
, errp
);
7526 bdrv_refresh_filename(bs
);
7527 if (bs
->exact_filename
[0] != '\0') {
7528 return path_combine(bs
->exact_filename
, "");
7531 error_setg(errp
, "Cannot generate a base directory for %s nodes",
7537 * Hot add/remove a BDS's child. So the user can take a child offline when
7538 * it is broken and take a new child online
7540 void bdrv_add_child(BlockDriverState
*parent_bs
, BlockDriverState
*child_bs
,
7544 if (!parent_bs
->drv
|| !parent_bs
->drv
->bdrv_add_child
) {
7545 error_setg(errp
, "The node %s does not support adding a child",
7546 bdrv_get_device_or_node_name(parent_bs
));
7550 if (!QLIST_EMPTY(&child_bs
->parents
)) {
7551 error_setg(errp
, "The node %s already has a parent",
7552 child_bs
->node_name
);
7556 parent_bs
->drv
->bdrv_add_child(parent_bs
, child_bs
, errp
);
7559 void bdrv_del_child(BlockDriverState
*parent_bs
, BdrvChild
*child
, Error
**errp
)
7563 if (!parent_bs
->drv
|| !parent_bs
->drv
->bdrv_del_child
) {
7564 error_setg(errp
, "The node %s does not support removing a child",
7565 bdrv_get_device_or_node_name(parent_bs
));
7569 QLIST_FOREACH(tmp
, &parent_bs
->children
, next
) {
7576 error_setg(errp
, "The node %s does not have a child named %s",
7577 bdrv_get_device_or_node_name(parent_bs
),
7578 bdrv_get_device_or_node_name(child
->bs
));
7582 parent_bs
->drv
->bdrv_del_child(parent_bs
, child
, errp
);
7585 int bdrv_make_empty(BdrvChild
*c
, Error
**errp
)
7587 BlockDriver
*drv
= c
->bs
->drv
;
7590 assert(c
->perm
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
));
7592 if (!drv
->bdrv_make_empty
) {
7593 error_setg(errp
, "%s does not support emptying nodes",
7598 ret
= drv
->bdrv_make_empty(c
->bs
);
7600 error_setg_errno(errp
, -ret
, "Failed to empty %s",
7609 * Return the child that @bs acts as an overlay for, and from which data may be
7610 * copied in COW or COR operations. Usually this is the backing file.
7612 BdrvChild
*bdrv_cow_child(BlockDriverState
*bs
)
7614 if (!bs
|| !bs
->drv
) {
7618 if (bs
->drv
->is_filter
) {
7626 assert(bs
->backing
->role
& BDRV_CHILD_COW
);
7631 * If @bs acts as a filter for exactly one of its children, return
7634 BdrvChild
*bdrv_filter_child(BlockDriverState
*bs
)
7638 if (!bs
|| !bs
->drv
) {
7642 if (!bs
->drv
->is_filter
) {
7646 /* Only one of @backing or @file may be used */
7647 assert(!(bs
->backing
&& bs
->file
));
7649 c
= bs
->backing
?: bs
->file
;
7654 assert(c
->role
& BDRV_CHILD_FILTERED
);
7659 * Return either the result of bdrv_cow_child() or bdrv_filter_child(),
7660 * whichever is non-NULL.
7662 * Return NULL if both are NULL.
7664 BdrvChild
*bdrv_filter_or_cow_child(BlockDriverState
*bs
)
7666 BdrvChild
*cow_child
= bdrv_cow_child(bs
);
7667 BdrvChild
*filter_child
= bdrv_filter_child(bs
);
7669 /* Filter nodes cannot have COW backing files */
7670 assert(!(cow_child
&& filter_child
));
7672 return cow_child
?: filter_child
;
7676 * Return the primary child of this node: For filters, that is the
7677 * filtered child. For other nodes, that is usually the child storing
7679 * (A generally more helpful description is that this is (usually) the
7680 * child that has the same filename as @bs.)
7682 * Drivers do not necessarily have a primary child; for example quorum
7685 BdrvChild
*bdrv_primary_child(BlockDriverState
*bs
)
7687 BdrvChild
*c
, *found
= NULL
;
7689 QLIST_FOREACH(c
, &bs
->children
, next
) {
7690 if (c
->role
& BDRV_CHILD_PRIMARY
) {
7699 static BlockDriverState
*bdrv_do_skip_filters(BlockDriverState
*bs
,
7700 bool stop_on_explicit_filter
)
7708 while (!(stop_on_explicit_filter
&& !bs
->implicit
)) {
7709 c
= bdrv_filter_child(bs
);
7712 * A filter that is embedded in a working block graph must
7713 * have a child. Assert this here so this function does
7714 * not return a filter node that is not expected by the
7717 assert(!bs
->drv
|| !bs
->drv
->is_filter
);
7723 * Note that this treats nodes with bs->drv == NULL as not being
7724 * filters (bs->drv == NULL should be replaced by something else
7726 * The advantage of this behavior is that this function will thus
7727 * always return a non-NULL value (given a non-NULL @bs).
7734 * Return the first BDS that has not been added implicitly or that
7735 * does not have a filtered child down the chain starting from @bs
7736 * (including @bs itself).
7738 BlockDriverState
*bdrv_skip_implicit_filters(BlockDriverState
*bs
)
7740 return bdrv_do_skip_filters(bs
, true);
7744 * Return the first BDS that does not have a filtered child down the
7745 * chain starting from @bs (including @bs itself).
7747 BlockDriverState
*bdrv_skip_filters(BlockDriverState
*bs
)
7749 return bdrv_do_skip_filters(bs
, false);
7753 * For a backing chain, return the first non-filter backing image of
7754 * the first non-filter image.
7756 BlockDriverState
*bdrv_backing_chain_next(BlockDriverState
*bs
)
7758 return bdrv_skip_filters(bdrv_cow_bs(bdrv_skip_filters(bs
)));
7762 * Check whether [offset, offset + bytes) overlaps with the cached
7763 * block-status data region.
7765 * If so, and @pnum is not NULL, set *pnum to `bsc.data_end - offset`,
7766 * which is what bdrv_bsc_is_data()'s interface needs.
7767 * Otherwise, *pnum is not touched.
7769 static bool bdrv_bsc_range_overlaps_locked(BlockDriverState
*bs
,
7770 int64_t offset
, int64_t bytes
,
7773 BdrvBlockStatusCache
*bsc
= qatomic_rcu_read(&bs
->block_status_cache
);
7777 qatomic_read(&bsc
->valid
) &&
7778 ranges_overlap(offset
, bytes
, bsc
->data_start
,
7779 bsc
->data_end
- bsc
->data_start
);
7781 if (overlaps
&& pnum
) {
7782 *pnum
= bsc
->data_end
- offset
;
7789 * See block_int.h for this function's documentation.
7791 bool bdrv_bsc_is_data(BlockDriverState
*bs
, int64_t offset
, int64_t *pnum
)
7793 RCU_READ_LOCK_GUARD();
7795 return bdrv_bsc_range_overlaps_locked(bs
, offset
, 1, pnum
);
7799 * See block_int.h for this function's documentation.
7801 void bdrv_bsc_invalidate_range(BlockDriverState
*bs
,
7802 int64_t offset
, int64_t bytes
)
7804 RCU_READ_LOCK_GUARD();
7806 if (bdrv_bsc_range_overlaps_locked(bs
, offset
, bytes
, NULL
)) {
7807 qatomic_set(&bs
->block_status_cache
->valid
, false);
7812 * See block_int.h for this function's documentation.
7814 void bdrv_bsc_fill(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
)
7816 BdrvBlockStatusCache
*new_bsc
= g_new(BdrvBlockStatusCache
, 1);
7817 BdrvBlockStatusCache
*old_bsc
;
7819 *new_bsc
= (BdrvBlockStatusCache
) {
7821 .data_start
= offset
,
7822 .data_end
= offset
+ bytes
,
7825 QEMU_LOCK_GUARD(&bs
->bsc_modify_lock
);
7827 old_bsc
= qatomic_rcu_read(&bs
->block_status_cache
);
7828 qatomic_rcu_set(&bs
->block_status_cache
, new_bsc
);
7830 g_free_rcu(old_bsc
, rcu
);