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/dirty-bitmap.h"
31 #include "block/fuse.h"
32 #include "block/nbd.h"
33 #include "block/qdict.h"
34 #include "qemu/error-report.h"
35 #include "block/module_block.h"
36 #include "qemu/main-loop.h"
37 #include "qemu/module.h"
38 #include "qapi/error.h"
39 #include "qapi/qmp/qdict.h"
40 #include "qapi/qmp/qjson.h"
41 #include "qapi/qmp/qnull.h"
42 #include "qapi/qmp/qstring.h"
43 #include "qapi/qobject-output-visitor.h"
44 #include "qapi/qapi-visit-block-core.h"
45 #include "sysemu/block-backend.h"
46 #include "qemu/notify.h"
47 #include "qemu/option.h"
48 #include "qemu/coroutine.h"
49 #include "block/qapi.h"
50 #include "qemu/timer.h"
51 #include "qemu/cutils.h"
53 #include "qemu/range.h"
55 #include "block/coroutines.h"
58 #include <sys/ioctl.h>
59 #include <sys/queue.h>
60 #if defined(HAVE_SYS_DISK_H)
69 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
71 /* Protected by BQL */
72 static QTAILQ_HEAD(, BlockDriverState
) graph_bdrv_states
=
73 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states
);
75 /* Protected by BQL */
76 static QTAILQ_HEAD(, BlockDriverState
) all_bdrv_states
=
77 QTAILQ_HEAD_INITIALIZER(all_bdrv_states
);
79 /* Protected by BQL */
80 static QLIST_HEAD(, BlockDriver
) bdrv_drivers
=
81 QLIST_HEAD_INITIALIZER(bdrv_drivers
);
83 static BlockDriverState
*bdrv_open_inherit(const char *filename
,
84 const char *reference
,
85 QDict
*options
, int flags
,
86 BlockDriverState
*parent
,
87 const BdrvChildClass
*child_class
,
88 BdrvChildRole child_role
,
91 static bool bdrv_recurse_has_child(BlockDriverState
*bs
,
92 BlockDriverState
*child
);
94 static void bdrv_replace_child_noperm(BdrvChild
*child
,
95 BlockDriverState
*new_bs
);
96 static void bdrv_remove_child(BdrvChild
*child
, Transaction
*tran
);
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 static bool bdrv_backing_overridden(BlockDriverState
*bs
);
106 static bool bdrv_change_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
107 GHashTable
*visited
, Transaction
*tran
,
110 /* If non-zero, use only whitelisted block drivers */
111 static int use_bdrv_whitelist
;
114 static int is_windows_drive_prefix(const char *filename
)
116 return (((filename
[0] >= 'a' && filename
[0] <= 'z') ||
117 (filename
[0] >= 'A' && filename
[0] <= 'Z')) &&
121 int is_windows_drive(const char *filename
)
123 if (is_windows_drive_prefix(filename
) &&
126 if (strstart(filename
, "\\\\.\\", NULL
) ||
127 strstart(filename
, "//./", NULL
))
133 size_t bdrv_opt_mem_align(BlockDriverState
*bs
)
135 if (!bs
|| !bs
->drv
) {
136 /* page size or 4k (hdd sector size) should be on the safe side */
137 return MAX(4096, qemu_real_host_page_size());
141 return bs
->bl
.opt_mem_alignment
;
144 size_t bdrv_min_mem_align(BlockDriverState
*bs
)
146 if (!bs
|| !bs
->drv
) {
147 /* page size or 4k (hdd sector size) should be on the safe side */
148 return MAX(4096, qemu_real_host_page_size());
152 return bs
->bl
.min_mem_alignment
;
155 /* check if the path starts with "<protocol>:" */
156 int path_has_protocol(const char *path
)
161 if (is_windows_drive(path
) ||
162 is_windows_drive_prefix(path
)) {
165 p
= path
+ strcspn(path
, ":/\\");
167 p
= path
+ strcspn(path
, ":/");
173 int path_is_absolute(const char *path
)
176 /* specific case for names like: "\\.\d:" */
177 if (is_windows_drive(path
) || is_windows_drive_prefix(path
)) {
180 return (*path
== '/' || *path
== '\\');
182 return (*path
== '/');
186 /* if filename is absolute, just return its duplicate. Otherwise, build a
187 path to it by considering it is relative to base_path. URL are
189 char *path_combine(const char *base_path
, const char *filename
)
191 const char *protocol_stripped
= NULL
;
196 if (path_is_absolute(filename
)) {
197 return g_strdup(filename
);
200 if (path_has_protocol(base_path
)) {
201 protocol_stripped
= strchr(base_path
, ':');
202 if (protocol_stripped
) {
206 p
= protocol_stripped
?: base_path
;
208 p1
= strrchr(base_path
, '/');
212 p2
= strrchr(base_path
, '\\');
213 if (!p1
|| p2
> p1
) {
228 result
= g_malloc(len
+ strlen(filename
) + 1);
229 memcpy(result
, base_path
, len
);
230 strcpy(result
+ len
, filename
);
236 * Helper function for bdrv_parse_filename() implementations to remove optional
237 * protocol prefixes (especially "file:") from a filename and for putting the
238 * stripped filename into the options QDict if there is such a prefix.
240 void bdrv_parse_filename_strip_prefix(const char *filename
, const char *prefix
,
243 if (strstart(filename
, prefix
, &filename
)) {
244 /* Stripping the explicit protocol prefix may result in a protocol
245 * prefix being (wrongly) detected (if the filename contains a colon) */
246 if (path_has_protocol(filename
)) {
247 GString
*fat_filename
;
249 /* This means there is some colon before the first slash; therefore,
250 * this cannot be an absolute path */
251 assert(!path_is_absolute(filename
));
253 /* And we can thus fix the protocol detection issue by prefixing it
255 fat_filename
= g_string_new("./");
256 g_string_append(fat_filename
, filename
);
258 assert(!path_has_protocol(fat_filename
->str
));
260 qdict_put(options
, "filename",
261 qstring_from_gstring(fat_filename
));
263 /* If no protocol prefix was detected, we can use the shortened
265 qdict_put_str(options
, "filename", filename
);
271 /* Returns whether the image file is opened as read-only. Note that this can
272 * return false and writing to the image file is still not possible because the
273 * image is inactivated. */
274 bool bdrv_is_read_only(BlockDriverState
*bs
)
277 return !(bs
->open_flags
& BDRV_O_RDWR
);
280 static int bdrv_can_set_read_only(BlockDriverState
*bs
, bool read_only
,
281 bool ignore_allow_rdw
, Error
**errp
)
285 /* Do not set read_only if copy_on_read is enabled */
286 if (bs
->copy_on_read
&& read_only
) {
287 error_setg(errp
, "Can't set node '%s' to r/o with copy-on-read enabled",
288 bdrv_get_device_or_node_name(bs
));
292 /* Do not clear read_only if it is prohibited */
293 if (!read_only
&& !(bs
->open_flags
& BDRV_O_ALLOW_RDWR
) &&
296 error_setg(errp
, "Node '%s' is read only",
297 bdrv_get_device_or_node_name(bs
));
305 * Called by a driver that can only provide a read-only image.
307 * Returns 0 if the node is already read-only or it could switch the node to
308 * read-only because BDRV_O_AUTO_RDONLY is set.
310 * Returns -EACCES if the node is read-write and BDRV_O_AUTO_RDONLY is not set
311 * or bdrv_can_set_read_only() forbids making the node read-only. If @errmsg
312 * is not NULL, it is used as the error message for the Error object.
314 int bdrv_apply_auto_read_only(BlockDriverState
*bs
, const char *errmsg
,
320 if (!(bs
->open_flags
& BDRV_O_RDWR
)) {
323 if (!(bs
->open_flags
& BDRV_O_AUTO_RDONLY
)) {
327 ret
= bdrv_can_set_read_only(bs
, true, false, NULL
);
332 bs
->open_flags
&= ~BDRV_O_RDWR
;
337 error_setg(errp
, "%s", errmsg
?: "Image is read-only");
342 * If @backing is empty, this function returns NULL without setting
343 * @errp. In all other cases, NULL will only be returned with @errp
346 * Therefore, a return value of NULL without @errp set means that
347 * there is no backing file; if @errp is set, there is one but its
348 * absolute filename cannot be generated.
350 char *bdrv_get_full_backing_filename_from_filename(const char *backed
,
354 if (backing
[0] == '\0') {
356 } else if (path_has_protocol(backing
) || path_is_absolute(backing
)) {
357 return g_strdup(backing
);
358 } else if (backed
[0] == '\0' || strstart(backed
, "json:", NULL
)) {
359 error_setg(errp
, "Cannot use relative backing file names for '%s'",
363 return path_combine(backed
, backing
);
368 * If @filename is empty or NULL, this function returns NULL without
369 * setting @errp. In all other cases, NULL will only be returned with
372 static char *bdrv_make_absolute_filename(BlockDriverState
*relative_to
,
373 const char *filename
, Error
**errp
)
375 char *dir
, *full_name
;
377 if (!filename
|| filename
[0] == '\0') {
379 } else if (path_has_protocol(filename
) || path_is_absolute(filename
)) {
380 return g_strdup(filename
);
383 dir
= bdrv_dirname(relative_to
, errp
);
388 full_name
= g_strconcat(dir
, filename
, NULL
);
393 char *bdrv_get_full_backing_filename(BlockDriverState
*bs
, Error
**errp
)
396 return bdrv_make_absolute_filename(bs
, bs
->backing_file
, errp
);
399 void bdrv_register(BlockDriver
*bdrv
)
401 assert(bdrv
->format_name
);
403 QLIST_INSERT_HEAD(&bdrv_drivers
, bdrv
, list
);
406 BlockDriverState
*bdrv_new(void)
408 BlockDriverState
*bs
;
413 bs
= g_new0(BlockDriverState
, 1);
414 QLIST_INIT(&bs
->dirty_bitmaps
);
415 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
416 QLIST_INIT(&bs
->op_blockers
[i
]);
418 qemu_co_mutex_init(&bs
->reqs_lock
);
419 qemu_mutex_init(&bs
->dirty_bitmap_mutex
);
421 bs
->aio_context
= qemu_get_aio_context();
423 qemu_co_queue_init(&bs
->flush_queue
);
425 qemu_co_mutex_init(&bs
->bsc_modify_lock
);
426 bs
->block_status_cache
= g_new0(BdrvBlockStatusCache
, 1);
428 for (i
= 0; i
< bdrv_drain_all_count
; i
++) {
429 bdrv_drained_begin(bs
);
432 QTAILQ_INSERT_TAIL(&all_bdrv_states
, bs
, bs_list
);
437 static BlockDriver
*bdrv_do_find_format(const char *format_name
)
442 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
443 if (!strcmp(drv1
->format_name
, format_name
)) {
451 BlockDriver
*bdrv_find_format(const char *format_name
)
458 drv1
= bdrv_do_find_format(format_name
);
463 /* The driver isn't registered, maybe we need to load a module */
464 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
465 if (!strcmp(block_driver_modules
[i
].format_name
, format_name
)) {
466 Error
*local_err
= NULL
;
467 int rv
= block_module_load(block_driver_modules
[i
].library_name
,
470 return bdrv_do_find_format(format_name
);
472 error_report_err(local_err
);
480 static int bdrv_format_is_whitelisted(const char *format_name
, bool read_only
)
482 static const char *whitelist_rw
[] = {
483 CONFIG_BDRV_RW_WHITELIST
486 static const char *whitelist_ro
[] = {
487 CONFIG_BDRV_RO_WHITELIST
492 if (!whitelist_rw
[0] && !whitelist_ro
[0]) {
493 return 1; /* no whitelist, anything goes */
496 for (p
= whitelist_rw
; *p
; p
++) {
497 if (!strcmp(format_name
, *p
)) {
502 for (p
= whitelist_ro
; *p
; p
++) {
503 if (!strcmp(format_name
, *p
)) {
511 int bdrv_is_whitelisted(BlockDriver
*drv
, bool read_only
)
514 return bdrv_format_is_whitelisted(drv
->format_name
, read_only
);
517 bool bdrv_uses_whitelist(void)
519 return use_bdrv_whitelist
;
522 typedef struct CreateCo
{
530 int coroutine_fn
bdrv_co_create(BlockDriver
*drv
, const char *filename
,
531 QemuOpts
*opts
, Error
**errp
)
537 if (!drv
->bdrv_co_create_opts
) {
538 error_setg(errp
, "Driver '%s' does not support image creation",
543 ret
= drv
->bdrv_co_create_opts(drv
, filename
, opts
, errp
);
544 if (ret
< 0 && !*errp
) {
545 error_setg_errno(errp
, -ret
, "Could not create image");
552 * Helper function for bdrv_create_file_fallback(): Resize @blk to at
553 * least the given @minimum_size.
555 * On success, return @blk's actual length.
556 * Otherwise, return -errno.
558 static int64_t create_file_fallback_truncate(BlockBackend
*blk
,
559 int64_t minimum_size
, Error
**errp
)
561 Error
*local_err
= NULL
;
567 ret
= blk_truncate(blk
, minimum_size
, false, PREALLOC_MODE_OFF
, 0,
569 if (ret
< 0 && ret
!= -ENOTSUP
) {
570 error_propagate(errp
, local_err
);
574 size
= blk_getlength(blk
);
576 error_free(local_err
);
577 error_setg_errno(errp
, -size
,
578 "Failed to inquire the new image file's length");
582 if (size
< minimum_size
) {
583 /* Need to grow the image, but we failed to do that */
584 error_propagate(errp
, local_err
);
588 error_free(local_err
);
595 * Helper function for bdrv_create_file_fallback(): Zero the first
596 * sector to remove any potentially pre-existing image header.
598 static int coroutine_fn
599 create_file_fallback_zero_first_sector(BlockBackend
*blk
,
600 int64_t current_size
,
603 int64_t bytes_to_clear
;
608 bytes_to_clear
= MIN(current_size
, BDRV_SECTOR_SIZE
);
609 if (bytes_to_clear
) {
610 ret
= blk_co_pwrite_zeroes(blk
, 0, bytes_to_clear
, BDRV_REQ_MAY_UNMAP
);
612 error_setg_errno(errp
, -ret
,
613 "Failed to clear the new image's first sector");
622 * Simple implementation of bdrv_co_create_opts for protocol drivers
623 * which only support creation via opening a file
624 * (usually existing raw storage device)
626 int coroutine_fn
bdrv_co_create_opts_simple(BlockDriver
*drv
,
627 const char *filename
,
635 PreallocMode prealloc
;
636 Error
*local_err
= NULL
;
641 size
= qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0);
642 buf
= qemu_opt_get_del(opts
, BLOCK_OPT_PREALLOC
);
643 prealloc
= qapi_enum_parse(&PreallocMode_lookup
, buf
,
644 PREALLOC_MODE_OFF
, &local_err
);
647 error_propagate(errp
, local_err
);
651 if (prealloc
!= PREALLOC_MODE_OFF
) {
652 error_setg(errp
, "Unsupported preallocation mode '%s'",
653 PreallocMode_str(prealloc
));
657 options
= qdict_new();
658 qdict_put_str(options
, "driver", drv
->format_name
);
660 blk
= blk_co_new_open(filename
, NULL
, options
,
661 BDRV_O_RDWR
| BDRV_O_RESIZE
, errp
);
663 error_prepend(errp
, "Protocol driver '%s' does not support image "
664 "creation, and opening the image failed: ",
669 size
= create_file_fallback_truncate(blk
, size
, errp
);
675 ret
= create_file_fallback_zero_first_sector(blk
, size
, errp
);
686 int coroutine_fn
bdrv_co_create_file(const char *filename
, QemuOpts
*opts
,
689 QemuOpts
*protocol_opts
;
696 drv
= bdrv_find_protocol(filename
, true, errp
);
701 if (!drv
->create_opts
) {
702 error_setg(errp
, "Driver '%s' does not support image creation",
708 * 'opts' contains a QemuOptsList with a combination of format and protocol
711 * The format properly removes its options, but the default values remain
712 * in 'opts->list'. So if the protocol has options with the same name
713 * (e.g. rbd has 'cluster_size' as qcow2), it will see the default values
714 * of the format, since for overlapping options, the format wins.
716 * To avoid this issue, lets convert QemuOpts to QDict, in this way we take
717 * only the set options, and then convert it back to QemuOpts, using the
718 * create_opts of the protocol. So the new QemuOpts, will contain only the
721 qdict
= qemu_opts_to_qdict(opts
, NULL
);
722 protocol_opts
= qemu_opts_from_qdict(drv
->create_opts
, qdict
, errp
);
723 if (protocol_opts
== NULL
) {
728 ret
= bdrv_co_create(drv
, filename
, protocol_opts
, errp
);
730 qemu_opts_del(protocol_opts
);
731 qobject_unref(qdict
);
735 int coroutine_fn
bdrv_co_delete_file(BlockDriverState
*bs
, Error
**errp
)
737 Error
*local_err
= NULL
;
742 assert_bdrv_graph_readable();
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
;
773 ret
= bdrv_co_delete_file(bs
, &local_err
);
775 * ENOTSUP will happen if the block driver doesn't support
776 * the 'bdrv_co_delete_file' interface. This is a predictable
777 * scenario and shouldn't be reported back to the user.
779 if (ret
== -ENOTSUP
) {
780 error_free(local_err
);
781 } else if (ret
< 0) {
782 error_report_err(local_err
);
787 * Try to get @bs's logical and physical block size.
788 * On success, store them in @bsz struct and return 0.
789 * On failure return -errno.
790 * @bs must not be empty.
792 int bdrv_probe_blocksizes(BlockDriverState
*bs
, BlockSizes
*bsz
)
794 BlockDriver
*drv
= bs
->drv
;
795 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
798 if (drv
&& drv
->bdrv_probe_blocksizes
) {
799 return drv
->bdrv_probe_blocksizes(bs
, bsz
);
800 } else if (filtered
) {
801 return bdrv_probe_blocksizes(filtered
, bsz
);
808 * Try to get @bs's geometry (cyls, heads, sectors).
809 * On success, store them in @geo struct and return 0.
810 * On failure return -errno.
811 * @bs must not be empty.
813 int bdrv_probe_geometry(BlockDriverState
*bs
, HDGeometry
*geo
)
815 BlockDriver
*drv
= bs
->drv
;
816 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
819 if (drv
&& drv
->bdrv_probe_geometry
) {
820 return drv
->bdrv_probe_geometry(bs
, geo
);
821 } else if (filtered
) {
822 return bdrv_probe_geometry(filtered
, geo
);
829 * Create a uniquely-named empty temporary file.
830 * Return the actual file name used upon success, otherwise NULL.
831 * This string should be freed with g_free() when not needed any longer.
833 * Note: creating a temporary file for the caller to (re)open is
834 * inherently racy. Use g_file_open_tmp() instead whenever practical.
836 char *create_tmp_file(Error
**errp
)
840 g_autofree
char *filename
= NULL
;
842 tmpdir
= g_get_tmp_dir();
845 * See commit 69bef79 ("block: use /var/tmp instead of /tmp for -snapshot")
847 * This function is used to create temporary disk images (like -snapshot),
848 * so the files can become very large. /tmp is often a tmpfs where as
849 * /var/tmp is usually on a disk, so more appropriate for disk images.
851 if (!g_strcmp0(tmpdir
, "/tmp")) {
856 filename
= g_strdup_printf("%s/vl.XXXXXX", tmpdir
);
857 fd
= g_mkstemp(filename
);
859 error_setg_errno(errp
, errno
, "Could not open temporary file '%s'",
865 return g_steal_pointer(&filename
);
869 * Detect host devices. By convention, /dev/cdrom[N] is always
870 * recognized as a host CDROM.
872 static BlockDriver
*find_hdev_driver(const char *filename
)
874 int score_max
= 0, score
;
875 BlockDriver
*drv
= NULL
, *d
;
878 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
879 if (d
->bdrv_probe_device
) {
880 score
= d
->bdrv_probe_device(filename
);
881 if (score
> score_max
) {
891 static BlockDriver
*bdrv_do_find_protocol(const char *protocol
)
896 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
897 if (drv1
->protocol_name
&& !strcmp(drv1
->protocol_name
, protocol
)) {
905 BlockDriver
*bdrv_find_protocol(const char *filename
,
906 bool allow_protocol_prefix
,
916 /* TODO Drivers without bdrv_file_open must be specified explicitly */
919 * XXX(hch): we really should not let host device detection
920 * override an explicit protocol specification, but moving this
921 * later breaks access to device names with colons in them.
922 * Thanks to the brain-dead persistent naming schemes on udev-
923 * based Linux systems those actually are quite common.
925 drv1
= find_hdev_driver(filename
);
930 if (!path_has_protocol(filename
) || !allow_protocol_prefix
) {
934 p
= strchr(filename
, ':');
937 if (len
> sizeof(protocol
) - 1)
938 len
= sizeof(protocol
) - 1;
939 memcpy(protocol
, filename
, len
);
940 protocol
[len
] = '\0';
942 drv1
= bdrv_do_find_protocol(protocol
);
947 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
948 if (block_driver_modules
[i
].protocol_name
&&
949 !strcmp(block_driver_modules
[i
].protocol_name
, protocol
)) {
950 int rv
= block_module_load(block_driver_modules
[i
].library_name
, errp
);
952 drv1
= bdrv_do_find_protocol(protocol
);
961 error_setg(errp
, "Unknown protocol '%s'", protocol
);
967 * Guess image format by probing its contents.
968 * This is not a good idea when your image is raw (CVE-2008-2004), but
969 * we do it anyway for backward compatibility.
971 * @buf contains the image's first @buf_size bytes.
972 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
973 * but can be smaller if the image file is smaller)
974 * @filename is its filename.
976 * For all block drivers, call the bdrv_probe() method to get its
978 * Return the first block driver with the highest probing score.
980 BlockDriver
*bdrv_probe_all(const uint8_t *buf
, int buf_size
,
981 const char *filename
)
983 int score_max
= 0, score
;
984 BlockDriver
*drv
= NULL
, *d
;
987 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
989 score
= d
->bdrv_probe(buf
, buf_size
, filename
);
990 if (score
> score_max
) {
1000 static int find_image_format(BlockBackend
*file
, const char *filename
,
1001 BlockDriver
**pdrv
, Error
**errp
)
1004 uint8_t buf
[BLOCK_PROBE_BUF_SIZE
];
1007 GLOBAL_STATE_CODE();
1009 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
1010 if (blk_is_sg(file
) || !blk_is_inserted(file
) || blk_getlength(file
) == 0) {
1015 ret
= blk_pread(file
, 0, sizeof(buf
), buf
, 0);
1017 error_setg_errno(errp
, -ret
, "Could not read image for determining its "
1023 drv
= bdrv_probe_all(buf
, sizeof(buf
), filename
);
1025 error_setg(errp
, "Could not determine image format: No compatible "
1036 * Set the current 'total_sectors' value
1037 * Return 0 on success, -errno on error.
1039 int coroutine_fn
bdrv_co_refresh_total_sectors(BlockDriverState
*bs
,
1042 BlockDriver
*drv
= bs
->drv
;
1044 assert_bdrv_graph_readable();
1050 /* Do not attempt drv->bdrv_co_getlength() on scsi-generic devices */
1054 /* query actual device if possible, otherwise just trust the hint */
1055 if (drv
->bdrv_co_getlength
) {
1056 int64_t length
= drv
->bdrv_co_getlength(bs
);
1060 hint
= DIV_ROUND_UP(length
, BDRV_SECTOR_SIZE
);
1063 bs
->total_sectors
= hint
;
1065 if (bs
->total_sectors
* BDRV_SECTOR_SIZE
> BDRV_MAX_LENGTH
) {
1073 * Combines a QDict of new block driver @options with any missing options taken
1074 * from @old_options, so that leaving out an option defaults to its old value.
1076 static void bdrv_join_options(BlockDriverState
*bs
, QDict
*options
,
1079 GLOBAL_STATE_CODE();
1080 if (bs
->drv
&& bs
->drv
->bdrv_join_options
) {
1081 bs
->drv
->bdrv_join_options(options
, old_options
);
1083 qdict_join(options
, old_options
, false);
1087 static BlockdevDetectZeroesOptions
bdrv_parse_detect_zeroes(QemuOpts
*opts
,
1091 Error
*local_err
= NULL
;
1092 char *value
= qemu_opt_get_del(opts
, "detect-zeroes");
1093 BlockdevDetectZeroesOptions detect_zeroes
=
1094 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup
, value
,
1095 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF
, &local_err
);
1096 GLOBAL_STATE_CODE();
1099 error_propagate(errp
, local_err
);
1100 return detect_zeroes
;
1103 if (detect_zeroes
== BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP
&&
1104 !(open_flags
& BDRV_O_UNMAP
))
1106 error_setg(errp
, "setting detect-zeroes to unmap is not allowed "
1107 "without setting discard operation to unmap");
1110 return detect_zeroes
;
1114 * Set open flags for aio engine
1116 * Return 0 on success, -1 if the engine specified is invalid
1118 int bdrv_parse_aio(const char *mode
, int *flags
)
1120 if (!strcmp(mode
, "threads")) {
1121 /* do nothing, default */
1122 } else if (!strcmp(mode
, "native")) {
1123 *flags
|= BDRV_O_NATIVE_AIO
;
1124 #ifdef CONFIG_LINUX_IO_URING
1125 } else if (!strcmp(mode
, "io_uring")) {
1126 *flags
|= BDRV_O_IO_URING
;
1136 * Set open flags for a given discard mode
1138 * Return 0 on success, -1 if the discard mode was invalid.
1140 int bdrv_parse_discard_flags(const char *mode
, int *flags
)
1142 *flags
&= ~BDRV_O_UNMAP
;
1144 if (!strcmp(mode
, "off") || !strcmp(mode
, "ignore")) {
1146 } else if (!strcmp(mode
, "on") || !strcmp(mode
, "unmap")) {
1147 *flags
|= BDRV_O_UNMAP
;
1156 * Set open flags for a given cache mode
1158 * Return 0 on success, -1 if the cache mode was invalid.
1160 int bdrv_parse_cache_mode(const char *mode
, int *flags
, bool *writethrough
)
1162 *flags
&= ~BDRV_O_CACHE_MASK
;
1164 if (!strcmp(mode
, "off") || !strcmp(mode
, "none")) {
1165 *writethrough
= false;
1166 *flags
|= BDRV_O_NOCACHE
;
1167 } else if (!strcmp(mode
, "directsync")) {
1168 *writethrough
= true;
1169 *flags
|= BDRV_O_NOCACHE
;
1170 } else if (!strcmp(mode
, "writeback")) {
1171 *writethrough
= false;
1172 } else if (!strcmp(mode
, "unsafe")) {
1173 *writethrough
= false;
1174 *flags
|= BDRV_O_NO_FLUSH
;
1175 } else if (!strcmp(mode
, "writethrough")) {
1176 *writethrough
= true;
1184 static char *bdrv_child_get_parent_desc(BdrvChild
*c
)
1186 BlockDriverState
*parent
= c
->opaque
;
1187 return g_strdup_printf("node '%s'", bdrv_get_node_name(parent
));
1190 static void bdrv_child_cb_drained_begin(BdrvChild
*child
)
1192 BlockDriverState
*bs
= child
->opaque
;
1193 bdrv_do_drained_begin_quiesce(bs
, NULL
);
1196 static bool bdrv_child_cb_drained_poll(BdrvChild
*child
)
1198 BlockDriverState
*bs
= child
->opaque
;
1199 return bdrv_drain_poll(bs
, NULL
, false);
1202 static void bdrv_child_cb_drained_end(BdrvChild
*child
)
1204 BlockDriverState
*bs
= child
->opaque
;
1205 bdrv_drained_end(bs
);
1208 static int bdrv_child_cb_inactivate(BdrvChild
*child
)
1210 BlockDriverState
*bs
= child
->opaque
;
1211 GLOBAL_STATE_CODE();
1212 assert(bs
->open_flags
& BDRV_O_INACTIVE
);
1216 static bool bdrv_child_cb_change_aio_ctx(BdrvChild
*child
, AioContext
*ctx
,
1217 GHashTable
*visited
, Transaction
*tran
,
1220 BlockDriverState
*bs
= child
->opaque
;
1221 return bdrv_change_aio_context(bs
, ctx
, visited
, tran
, errp
);
1225 * Returns the options and flags that a temporary snapshot should get, based on
1226 * the originally requested flags (the originally requested image will have
1227 * flags like a backing file)
1229 static void bdrv_temp_snapshot_options(int *child_flags
, QDict
*child_options
,
1230 int parent_flags
, QDict
*parent_options
)
1232 GLOBAL_STATE_CODE();
1233 *child_flags
= (parent_flags
& ~BDRV_O_SNAPSHOT
) | BDRV_O_TEMPORARY
;
1235 /* For temporary files, unconditional cache=unsafe is fine */
1236 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_DIRECT
, "off");
1237 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_NO_FLUSH
, "on");
1239 /* Copy the read-only and discard options from the parent */
1240 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1241 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_DISCARD
);
1243 /* aio=native doesn't work for cache.direct=off, so disable it for the
1244 * temporary snapshot */
1245 *child_flags
&= ~BDRV_O_NATIVE_AIO
;
1248 static void bdrv_backing_attach(BdrvChild
*c
)
1250 BlockDriverState
*parent
= c
->opaque
;
1251 BlockDriverState
*backing_hd
= c
->bs
;
1253 GLOBAL_STATE_CODE();
1254 assert(!parent
->backing_blocker
);
1255 error_setg(&parent
->backing_blocker
,
1256 "node is used as backing hd of '%s'",
1257 bdrv_get_device_or_node_name(parent
));
1259 bdrv_refresh_filename(backing_hd
);
1261 parent
->open_flags
&= ~BDRV_O_NO_BACKING
;
1263 bdrv_op_block_all(backing_hd
, parent
->backing_blocker
);
1264 /* Otherwise we won't be able to commit or stream */
1265 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_COMMIT_TARGET
,
1266 parent
->backing_blocker
);
1267 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_STREAM
,
1268 parent
->backing_blocker
);
1270 * We do backup in 3 ways:
1272 * The target bs is new opened, and the source is top BDS
1273 * 2. blockdev backup
1274 * Both the source and the target are top BDSes.
1275 * 3. internal backup(used for block replication)
1276 * Both the source and the target are backing file
1278 * In case 1 and 2, neither the source nor the target is the backing file.
1279 * In case 3, we will block the top BDS, so there is only one block job
1280 * for the top BDS and its backing chain.
1282 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_SOURCE
,
1283 parent
->backing_blocker
);
1284 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_TARGET
,
1285 parent
->backing_blocker
);
1288 static void bdrv_backing_detach(BdrvChild
*c
)
1290 BlockDriverState
*parent
= c
->opaque
;
1292 GLOBAL_STATE_CODE();
1293 assert(parent
->backing_blocker
);
1294 bdrv_op_unblock_all(c
->bs
, parent
->backing_blocker
);
1295 error_free(parent
->backing_blocker
);
1296 parent
->backing_blocker
= NULL
;
1299 static int bdrv_backing_update_filename(BdrvChild
*c
, BlockDriverState
*base
,
1300 const char *filename
, Error
**errp
)
1302 BlockDriverState
*parent
= c
->opaque
;
1303 bool read_only
= bdrv_is_read_only(parent
);
1305 GLOBAL_STATE_CODE();
1308 ret
= bdrv_reopen_set_read_only(parent
, false, errp
);
1314 ret
= bdrv_change_backing_file(parent
, filename
,
1315 base
->drv
? base
->drv
->format_name
: "",
1318 error_setg_errno(errp
, -ret
, "Could not update backing file link");
1322 bdrv_reopen_set_read_only(parent
, true, NULL
);
1329 * Returns the options and flags that a generic child of a BDS should
1330 * get, based on the given options and flags for the parent BDS.
1332 static void bdrv_inherited_options(BdrvChildRole role
, bool parent_is_format
,
1333 int *child_flags
, QDict
*child_options
,
1334 int parent_flags
, QDict
*parent_options
)
1336 int flags
= parent_flags
;
1337 GLOBAL_STATE_CODE();
1340 * First, decide whether to set, clear, or leave BDRV_O_PROTOCOL.
1341 * Generally, the question to answer is: Should this child be
1342 * format-probed by default?
1346 * Pure and non-filtered data children of non-format nodes should
1347 * be probed by default (even when the node itself has BDRV_O_PROTOCOL
1348 * set). This only affects a very limited set of drivers (namely
1349 * quorum and blkverify when this comment was written).
1350 * Force-clear BDRV_O_PROTOCOL then.
1352 if (!parent_is_format
&&
1353 (role
& BDRV_CHILD_DATA
) &&
1354 !(role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_FILTERED
)))
1356 flags
&= ~BDRV_O_PROTOCOL
;
1360 * All children of format nodes (except for COW children) and all
1361 * metadata children in general should never be format-probed.
1362 * Force-set BDRV_O_PROTOCOL then.
1364 if ((parent_is_format
&& !(role
& BDRV_CHILD_COW
)) ||
1365 (role
& BDRV_CHILD_METADATA
))
1367 flags
|= BDRV_O_PROTOCOL
;
1371 * If the cache mode isn't explicitly set, inherit direct and no-flush from
1374 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_DIRECT
);
1375 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_NO_FLUSH
);
1376 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_FORCE_SHARE
);
1378 if (role
& BDRV_CHILD_COW
) {
1379 /* backing files are opened read-only by default */
1380 qdict_set_default_str(child_options
, BDRV_OPT_READ_ONLY
, "on");
1381 qdict_set_default_str(child_options
, BDRV_OPT_AUTO_READ_ONLY
, "off");
1383 /* Inherit the read-only option from the parent if it's not set */
1384 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1385 qdict_copy_default(child_options
, parent_options
,
1386 BDRV_OPT_AUTO_READ_ONLY
);
1390 * bdrv_co_pdiscard() respects unmap policy for the parent, so we
1391 * can default to enable it on lower layers regardless of the
1394 qdict_set_default_str(child_options
, BDRV_OPT_DISCARD
, "unmap");
1396 /* Clear flags that only apply to the top layer */
1397 flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_COPY_ON_READ
);
1399 if (role
& BDRV_CHILD_METADATA
) {
1400 flags
&= ~BDRV_O_NO_IO
;
1402 if (role
& BDRV_CHILD_COW
) {
1403 flags
&= ~BDRV_O_TEMPORARY
;
1406 *child_flags
= flags
;
1409 static void GRAPH_WRLOCK
bdrv_child_cb_attach(BdrvChild
*child
)
1411 BlockDriverState
*bs
= child
->opaque
;
1413 assert_bdrv_graph_writable();
1414 QLIST_INSERT_HEAD(&bs
->children
, child
, next
);
1415 if (bs
->drv
->is_filter
|| (child
->role
& BDRV_CHILD_FILTERED
)) {
1417 * Here we handle filters and block/raw-format.c when it behave like
1418 * filter. They generally have a single PRIMARY child, which is also the
1419 * FILTERED child, and that they may have multiple more children, which
1420 * are neither PRIMARY nor FILTERED. And never we have a COW child here.
1421 * So bs->file will be the PRIMARY child, unless the PRIMARY child goes
1422 * into bs->backing on exceptional cases; and bs->backing will be
1425 assert(!(child
->role
& BDRV_CHILD_COW
));
1426 if (child
->role
& BDRV_CHILD_PRIMARY
) {
1427 assert(child
->role
& BDRV_CHILD_FILTERED
);
1428 assert(!bs
->backing
);
1431 if (bs
->drv
->filtered_child_is_backing
) {
1432 bs
->backing
= child
;
1437 assert(!(child
->role
& BDRV_CHILD_FILTERED
));
1439 } else if (child
->role
& BDRV_CHILD_COW
) {
1440 assert(bs
->drv
->supports_backing
);
1441 assert(!(child
->role
& BDRV_CHILD_PRIMARY
));
1442 assert(!bs
->backing
);
1443 bs
->backing
= child
;
1444 bdrv_backing_attach(child
);
1445 } else if (child
->role
& BDRV_CHILD_PRIMARY
) {
1451 static void GRAPH_WRLOCK
bdrv_child_cb_detach(BdrvChild
*child
)
1453 BlockDriverState
*bs
= child
->opaque
;
1455 if (child
->role
& BDRV_CHILD_COW
) {
1456 bdrv_backing_detach(child
);
1459 assert_bdrv_graph_writable();
1460 QLIST_REMOVE(child
, next
);
1461 if (child
== bs
->backing
) {
1462 assert(child
!= bs
->file
);
1464 } else if (child
== bs
->file
) {
1469 static int bdrv_child_cb_update_filename(BdrvChild
*c
, BlockDriverState
*base
,
1470 const char *filename
, Error
**errp
)
1472 if (c
->role
& BDRV_CHILD_COW
) {
1473 return bdrv_backing_update_filename(c
, base
, filename
, errp
);
1478 AioContext
*child_of_bds_get_parent_aio_context(BdrvChild
*c
)
1480 BlockDriverState
*bs
= c
->opaque
;
1483 return bdrv_get_aio_context(bs
);
1486 const BdrvChildClass child_of_bds
= {
1487 .parent_is_bds
= true,
1488 .get_parent_desc
= bdrv_child_get_parent_desc
,
1489 .inherit_options
= bdrv_inherited_options
,
1490 .drained_begin
= bdrv_child_cb_drained_begin
,
1491 .drained_poll
= bdrv_child_cb_drained_poll
,
1492 .drained_end
= bdrv_child_cb_drained_end
,
1493 .attach
= bdrv_child_cb_attach
,
1494 .detach
= bdrv_child_cb_detach
,
1495 .inactivate
= bdrv_child_cb_inactivate
,
1496 .change_aio_ctx
= bdrv_child_cb_change_aio_ctx
,
1497 .update_filename
= bdrv_child_cb_update_filename
,
1498 .get_parent_aio_context
= child_of_bds_get_parent_aio_context
,
1501 AioContext
*bdrv_child_get_parent_aio_context(BdrvChild
*c
)
1504 return c
->klass
->get_parent_aio_context(c
);
1507 static int bdrv_open_flags(BlockDriverState
*bs
, int flags
)
1509 int open_flags
= flags
;
1510 GLOBAL_STATE_CODE();
1513 * Clear flags that are internal to the block layer before opening the
1516 open_flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_PROTOCOL
);
1521 static void update_flags_from_options(int *flags
, QemuOpts
*opts
)
1523 GLOBAL_STATE_CODE();
1525 *flags
&= ~(BDRV_O_CACHE_MASK
| BDRV_O_RDWR
| BDRV_O_AUTO_RDONLY
);
1527 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_NO_FLUSH
, false)) {
1528 *flags
|= BDRV_O_NO_FLUSH
;
1531 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_DIRECT
, false)) {
1532 *flags
|= BDRV_O_NOCACHE
;
1535 if (!qemu_opt_get_bool_del(opts
, BDRV_OPT_READ_ONLY
, false)) {
1536 *flags
|= BDRV_O_RDWR
;
1539 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_AUTO_READ_ONLY
, false)) {
1540 *flags
|= BDRV_O_AUTO_RDONLY
;
1544 static void update_options_from_flags(QDict
*options
, int flags
)
1546 GLOBAL_STATE_CODE();
1547 if (!qdict_haskey(options
, BDRV_OPT_CACHE_DIRECT
)) {
1548 qdict_put_bool(options
, BDRV_OPT_CACHE_DIRECT
, flags
& BDRV_O_NOCACHE
);
1550 if (!qdict_haskey(options
, BDRV_OPT_CACHE_NO_FLUSH
)) {
1551 qdict_put_bool(options
, BDRV_OPT_CACHE_NO_FLUSH
,
1552 flags
& BDRV_O_NO_FLUSH
);
1554 if (!qdict_haskey(options
, BDRV_OPT_READ_ONLY
)) {
1555 qdict_put_bool(options
, BDRV_OPT_READ_ONLY
, !(flags
& BDRV_O_RDWR
));
1557 if (!qdict_haskey(options
, BDRV_OPT_AUTO_READ_ONLY
)) {
1558 qdict_put_bool(options
, BDRV_OPT_AUTO_READ_ONLY
,
1559 flags
& BDRV_O_AUTO_RDONLY
);
1563 static void bdrv_assign_node_name(BlockDriverState
*bs
,
1564 const char *node_name
,
1567 char *gen_node_name
= NULL
;
1568 GLOBAL_STATE_CODE();
1571 node_name
= gen_node_name
= id_generate(ID_BLOCK
);
1572 } else if (!id_wellformed(node_name
)) {
1574 * Check for empty string or invalid characters, but not if it is
1575 * generated (generated names use characters not available to the user)
1577 error_setg(errp
, "Invalid node-name: '%s'", node_name
);
1581 /* takes care of avoiding namespaces collisions */
1582 if (blk_by_name(node_name
)) {
1583 error_setg(errp
, "node-name=%s is conflicting with a device id",
1588 /* takes care of avoiding duplicates node names */
1589 if (bdrv_find_node(node_name
)) {
1590 error_setg(errp
, "Duplicate nodes with node-name='%s'", node_name
);
1594 /* Make sure that the node name isn't truncated */
1595 if (strlen(node_name
) >= sizeof(bs
->node_name
)) {
1596 error_setg(errp
, "Node name too long");
1600 /* copy node name into the bs and insert it into the graph list */
1601 pstrcpy(bs
->node_name
, sizeof(bs
->node_name
), node_name
);
1602 QTAILQ_INSERT_TAIL(&graph_bdrv_states
, bs
, node_list
);
1604 g_free(gen_node_name
);
1608 * The caller must always hold @bs AioContext lock, because this function calls
1609 * bdrv_refresh_total_sectors() which polls when called from non-coroutine
1612 static int no_coroutine_fn GRAPH_UNLOCKED
1613 bdrv_open_driver(BlockDriverState
*bs
, BlockDriver
*drv
, const char *node_name
,
1614 QDict
*options
, int open_flags
, Error
**errp
)
1617 Error
*local_err
= NULL
;
1619 GLOBAL_STATE_CODE();
1621 bdrv_assign_node_name(bs
, node_name
, &local_err
);
1623 error_propagate(errp
, local_err
);
1628 bs
->opaque
= g_malloc0(drv
->instance_size
);
1630 if (drv
->bdrv_file_open
) {
1631 assert(!drv
->bdrv_needs_filename
|| bs
->filename
[0]);
1632 ret
= drv
->bdrv_file_open(bs
, options
, open_flags
, &local_err
);
1633 } else if (drv
->bdrv_open
) {
1634 ret
= drv
->bdrv_open(bs
, options
, open_flags
, &local_err
);
1641 error_propagate(errp
, local_err
);
1642 } else if (bs
->filename
[0]) {
1643 error_setg_errno(errp
, -ret
, "Could not open '%s'", bs
->filename
);
1645 error_setg_errno(errp
, -ret
, "Could not open image");
1650 assert(!(bs
->supported_read_flags
& ~BDRV_REQ_MASK
));
1651 assert(!(bs
->supported_write_flags
& ~BDRV_REQ_MASK
));
1654 * Always allow the BDRV_REQ_REGISTERED_BUF optimization hint. This saves
1655 * drivers that pass read/write requests through to a child the trouble of
1656 * declaring support explicitly.
1658 * Drivers must not propagate this flag accidentally when they initiate I/O
1659 * to a bounce buffer. That case should be rare though.
1661 bs
->supported_read_flags
|= BDRV_REQ_REGISTERED_BUF
;
1662 bs
->supported_write_flags
|= BDRV_REQ_REGISTERED_BUF
;
1664 /* Get the context after .bdrv_open, it can change the context */
1665 ctx
= bdrv_get_aio_context(bs
);
1666 aio_context_acquire(ctx
);
1668 ret
= bdrv_refresh_total_sectors(bs
, bs
->total_sectors
);
1670 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
1671 aio_context_release(ctx
);
1675 bdrv_graph_rdlock_main_loop();
1676 bdrv_refresh_limits(bs
, NULL
, &local_err
);
1677 bdrv_graph_rdunlock_main_loop();
1678 aio_context_release(ctx
);
1681 error_propagate(errp
, local_err
);
1685 assert(bdrv_opt_mem_align(bs
) != 0);
1686 assert(bdrv_min_mem_align(bs
) != 0);
1687 assert(is_power_of_2(bs
->bl
.request_alignment
));
1689 for (i
= 0; i
< bs
->quiesce_counter
; i
++) {
1690 if (drv
->bdrv_drain_begin
) {
1691 drv
->bdrv_drain_begin(bs
);
1698 if (bs
->file
!= NULL
) {
1699 bdrv_unref_child(bs
, bs
->file
);
1708 * Create and open a block node.
1710 * @options is a QDict of options to pass to the block drivers, or NULL for an
1711 * empty set of options. The reference to the QDict belongs to the block layer
1712 * after the call (even on failure), so if the caller intends to reuse the
1713 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
1715 BlockDriverState
*bdrv_new_open_driver_opts(BlockDriver
*drv
,
1716 const char *node_name
,
1717 QDict
*options
, int flags
,
1720 BlockDriverState
*bs
;
1723 GLOBAL_STATE_CODE();
1726 bs
->open_flags
= flags
;
1727 bs
->options
= options
?: qdict_new();
1728 bs
->explicit_options
= qdict_clone_shallow(bs
->options
);
1731 update_options_from_flags(bs
->options
, flags
);
1733 ret
= bdrv_open_driver(bs
, drv
, node_name
, bs
->options
, flags
, errp
);
1735 qobject_unref(bs
->explicit_options
);
1736 bs
->explicit_options
= NULL
;
1737 qobject_unref(bs
->options
);
1746 /* Create and open a block node. */
1747 BlockDriverState
*bdrv_new_open_driver(BlockDriver
*drv
, const char *node_name
,
1748 int flags
, Error
**errp
)
1750 GLOBAL_STATE_CODE();
1751 return bdrv_new_open_driver_opts(drv
, node_name
, NULL
, flags
, errp
);
1754 QemuOptsList bdrv_runtime_opts
= {
1755 .name
= "bdrv_common",
1756 .head
= QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts
.head
),
1759 .name
= "node-name",
1760 .type
= QEMU_OPT_STRING
,
1761 .help
= "Node name of the block device node",
1765 .type
= QEMU_OPT_STRING
,
1766 .help
= "Block driver to use for the node",
1769 .name
= BDRV_OPT_CACHE_DIRECT
,
1770 .type
= QEMU_OPT_BOOL
,
1771 .help
= "Bypass software writeback cache on the host",
1774 .name
= BDRV_OPT_CACHE_NO_FLUSH
,
1775 .type
= QEMU_OPT_BOOL
,
1776 .help
= "Ignore flush requests",
1779 .name
= BDRV_OPT_READ_ONLY
,
1780 .type
= QEMU_OPT_BOOL
,
1781 .help
= "Node is opened in read-only mode",
1784 .name
= BDRV_OPT_AUTO_READ_ONLY
,
1785 .type
= QEMU_OPT_BOOL
,
1786 .help
= "Node can become read-only if opening read-write fails",
1789 .name
= "detect-zeroes",
1790 .type
= QEMU_OPT_STRING
,
1791 .help
= "try to optimize zero writes (off, on, unmap)",
1794 .name
= BDRV_OPT_DISCARD
,
1795 .type
= QEMU_OPT_STRING
,
1796 .help
= "discard operation (ignore/off, unmap/on)",
1799 .name
= BDRV_OPT_FORCE_SHARE
,
1800 .type
= QEMU_OPT_BOOL
,
1801 .help
= "always accept other writers (default: off)",
1803 { /* end of list */ }
1807 QemuOptsList bdrv_create_opts_simple
= {
1808 .name
= "simple-create-opts",
1809 .head
= QTAILQ_HEAD_INITIALIZER(bdrv_create_opts_simple
.head
),
1812 .name
= BLOCK_OPT_SIZE
,
1813 .type
= QEMU_OPT_SIZE
,
1814 .help
= "Virtual disk size"
1817 .name
= BLOCK_OPT_PREALLOC
,
1818 .type
= QEMU_OPT_STRING
,
1819 .help
= "Preallocation mode (allowed values: off)"
1821 { /* end of list */ }
1826 * Common part for opening disk images and files
1828 * Removes all processed options from *options.
1830 static int bdrv_open_common(BlockDriverState
*bs
, BlockBackend
*file
,
1831 QDict
*options
, Error
**errp
)
1833 int ret
, open_flags
;
1834 const char *filename
;
1835 const char *driver_name
= NULL
;
1836 const char *node_name
= NULL
;
1837 const char *discard
;
1840 Error
*local_err
= NULL
;
1843 assert(bs
->file
== NULL
);
1844 assert(options
!= NULL
&& bs
->options
!= options
);
1845 GLOBAL_STATE_CODE();
1847 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
1848 if (!qemu_opts_absorb_qdict(opts
, options
, errp
)) {
1853 update_flags_from_options(&bs
->open_flags
, opts
);
1855 driver_name
= qemu_opt_get(opts
, "driver");
1856 drv
= bdrv_find_format(driver_name
);
1857 assert(drv
!= NULL
);
1859 bs
->force_share
= qemu_opt_get_bool(opts
, BDRV_OPT_FORCE_SHARE
, false);
1861 if (bs
->force_share
&& (bs
->open_flags
& BDRV_O_RDWR
)) {
1863 BDRV_OPT_FORCE_SHARE
1864 "=on can only be used with read-only images");
1870 bdrv_refresh_filename(blk_bs(file
));
1871 filename
= blk_bs(file
)->filename
;
1874 * Caution: while qdict_get_try_str() is fine, getting
1875 * non-string types would require more care. When @options
1876 * come from -blockdev or blockdev_add, its members are typed
1877 * according to the QAPI schema, but when they come from
1878 * -drive, they're all QString.
1880 filename
= qdict_get_try_str(options
, "filename");
1883 if (drv
->bdrv_needs_filename
&& (!filename
|| !filename
[0])) {
1884 error_setg(errp
, "The '%s' block driver requires a file name",
1890 trace_bdrv_open_common(bs
, filename
?: "", bs
->open_flags
,
1893 ro
= bdrv_is_read_only(bs
);
1895 if (use_bdrv_whitelist
&& !bdrv_is_whitelisted(drv
, ro
)) {
1896 if (!ro
&& bdrv_is_whitelisted(drv
, true)) {
1897 ret
= bdrv_apply_auto_read_only(bs
, NULL
, NULL
);
1903 !ro
&& bdrv_is_whitelisted(drv
, true)
1904 ? "Driver '%s' can only be used for read-only devices"
1905 : "Driver '%s' is not whitelisted",
1911 /* bdrv_new() and bdrv_close() make it so */
1912 assert(qatomic_read(&bs
->copy_on_read
) == 0);
1914 if (bs
->open_flags
& BDRV_O_COPY_ON_READ
) {
1916 bdrv_enable_copy_on_read(bs
);
1918 error_setg(errp
, "Can't use copy-on-read on read-only device");
1924 discard
= qemu_opt_get(opts
, BDRV_OPT_DISCARD
);
1925 if (discard
!= NULL
) {
1926 if (bdrv_parse_discard_flags(discard
, &bs
->open_flags
) != 0) {
1927 error_setg(errp
, "Invalid discard option");
1934 bdrv_parse_detect_zeroes(opts
, bs
->open_flags
, &local_err
);
1936 error_propagate(errp
, local_err
);
1941 if (filename
!= NULL
) {
1942 pstrcpy(bs
->filename
, sizeof(bs
->filename
), filename
);
1944 bs
->filename
[0] = '\0';
1946 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
), bs
->filename
);
1948 /* Open the image, either directly or using a protocol */
1949 open_flags
= bdrv_open_flags(bs
, bs
->open_flags
);
1950 node_name
= qemu_opt_get(opts
, "node-name");
1952 assert(!drv
->bdrv_file_open
|| file
== NULL
);
1953 ret
= bdrv_open_driver(bs
, drv
, node_name
, options
, open_flags
, errp
);
1958 qemu_opts_del(opts
);
1962 qemu_opts_del(opts
);
1966 static QDict
*parse_json_filename(const char *filename
, Error
**errp
)
1968 QObject
*options_obj
;
1971 GLOBAL_STATE_CODE();
1973 ret
= strstart(filename
, "json:", &filename
);
1976 options_obj
= qobject_from_json(filename
, errp
);
1978 error_prepend(errp
, "Could not parse the JSON options: ");
1982 options
= qobject_to(QDict
, options_obj
);
1984 qobject_unref(options_obj
);
1985 error_setg(errp
, "Invalid JSON object given");
1989 qdict_flatten(options
);
1994 static void parse_json_protocol(QDict
*options
, const char **pfilename
,
1997 QDict
*json_options
;
1998 Error
*local_err
= NULL
;
1999 GLOBAL_STATE_CODE();
2001 /* Parse json: pseudo-protocol */
2002 if (!*pfilename
|| !g_str_has_prefix(*pfilename
, "json:")) {
2006 json_options
= parse_json_filename(*pfilename
, &local_err
);
2008 error_propagate(errp
, local_err
);
2012 /* Options given in the filename have lower priority than options
2013 * specified directly */
2014 qdict_join(options
, json_options
, false);
2015 qobject_unref(json_options
);
2020 * Fills in default options for opening images and converts the legacy
2021 * filename/flags pair to option QDict entries.
2022 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
2023 * block driver has been specified explicitly.
2025 static int bdrv_fill_options(QDict
**options
, const char *filename
,
2026 int *flags
, Error
**errp
)
2028 const char *drvname
;
2029 bool protocol
= *flags
& BDRV_O_PROTOCOL
;
2030 bool parse_filename
= false;
2031 BlockDriver
*drv
= NULL
;
2032 Error
*local_err
= NULL
;
2034 GLOBAL_STATE_CODE();
2037 * Caution: while qdict_get_try_str() is fine, getting non-string
2038 * types would require more care. When @options come from
2039 * -blockdev or blockdev_add, its members are typed according to
2040 * the QAPI schema, but when they come from -drive, they're all
2043 drvname
= qdict_get_try_str(*options
, "driver");
2045 drv
= bdrv_find_format(drvname
);
2047 error_setg(errp
, "Unknown driver '%s'", drvname
);
2050 /* If the user has explicitly specified the driver, this choice should
2051 * override the BDRV_O_PROTOCOL flag */
2052 protocol
= drv
->bdrv_file_open
;
2056 *flags
|= BDRV_O_PROTOCOL
;
2058 *flags
&= ~BDRV_O_PROTOCOL
;
2061 /* Translate cache options from flags into options */
2062 update_options_from_flags(*options
, *flags
);
2064 /* Fetch the file name from the options QDict if necessary */
2065 if (protocol
&& filename
) {
2066 if (!qdict_haskey(*options
, "filename")) {
2067 qdict_put_str(*options
, "filename", filename
);
2068 parse_filename
= true;
2070 error_setg(errp
, "Can't specify 'file' and 'filename' options at "
2076 /* Find the right block driver */
2077 /* See cautionary note on accessing @options above */
2078 filename
= qdict_get_try_str(*options
, "filename");
2080 if (!drvname
&& protocol
) {
2082 drv
= bdrv_find_protocol(filename
, parse_filename
, errp
);
2087 drvname
= drv
->format_name
;
2088 qdict_put_str(*options
, "driver", drvname
);
2090 error_setg(errp
, "Must specify either driver or file");
2095 assert(drv
|| !protocol
);
2097 /* Driver-specific filename parsing */
2098 if (drv
&& drv
->bdrv_parse_filename
&& parse_filename
) {
2099 drv
->bdrv_parse_filename(filename
, *options
, &local_err
);
2101 error_propagate(errp
, local_err
);
2105 if (!drv
->bdrv_needs_filename
) {
2106 qdict_del(*options
, "filename");
2113 typedef struct BlockReopenQueueEntry
{
2116 BDRVReopenState state
;
2117 QTAILQ_ENTRY(BlockReopenQueueEntry
) entry
;
2118 } BlockReopenQueueEntry
;
2121 * Return the flags that @bs will have after the reopens in @q have
2122 * successfully completed. If @q is NULL (or @bs is not contained in @q),
2123 * return the current flags.
2125 static int bdrv_reopen_get_flags(BlockReopenQueue
*q
, BlockDriverState
*bs
)
2127 BlockReopenQueueEntry
*entry
;
2130 QTAILQ_FOREACH(entry
, q
, entry
) {
2131 if (entry
->state
.bs
== bs
) {
2132 return entry
->state
.flags
;
2137 return bs
->open_flags
;
2140 /* Returns whether the image file can be written to after the reopen queue @q
2141 * has been successfully applied, or right now if @q is NULL. */
2142 static bool bdrv_is_writable_after_reopen(BlockDriverState
*bs
,
2143 BlockReopenQueue
*q
)
2145 int flags
= bdrv_reopen_get_flags(q
, bs
);
2147 return (flags
& (BDRV_O_RDWR
| BDRV_O_INACTIVE
)) == BDRV_O_RDWR
;
2151 * Return whether the BDS can be written to. This is not necessarily
2152 * the same as !bdrv_is_read_only(bs), as inactivated images may not
2153 * be written to but do not count as read-only images.
2155 bool bdrv_is_writable(BlockDriverState
*bs
)
2158 return bdrv_is_writable_after_reopen(bs
, NULL
);
2161 static char *bdrv_child_user_desc(BdrvChild
*c
)
2163 GLOBAL_STATE_CODE();
2164 return c
->klass
->get_parent_desc(c
);
2168 * Check that @a allows everything that @b needs. @a and @b must reference same
2171 static bool bdrv_a_allow_b(BdrvChild
*a
, BdrvChild
*b
, Error
**errp
)
2173 const char *child_bs_name
;
2174 g_autofree
char *a_user
= NULL
;
2175 g_autofree
char *b_user
= NULL
;
2176 g_autofree
char *perms
= NULL
;
2179 assert(a
->bs
== b
->bs
);
2180 GLOBAL_STATE_CODE();
2182 if ((b
->perm
& a
->shared_perm
) == b
->perm
) {
2186 child_bs_name
= bdrv_get_node_name(b
->bs
);
2187 a_user
= bdrv_child_user_desc(a
);
2188 b_user
= bdrv_child_user_desc(b
);
2189 perms
= bdrv_perm_names(b
->perm
& ~a
->shared_perm
);
2191 error_setg(errp
, "Permission conflict on node '%s': permissions '%s' are "
2192 "both required by %s (uses node '%s' as '%s' child) and "
2193 "unshared by %s (uses node '%s' as '%s' child).",
2194 child_bs_name
, perms
,
2195 b_user
, child_bs_name
, b
->name
,
2196 a_user
, child_bs_name
, a
->name
);
2201 static bool bdrv_parent_perms_conflict(BlockDriverState
*bs
, Error
**errp
)
2204 GLOBAL_STATE_CODE();
2207 * During the loop we'll look at each pair twice. That's correct because
2208 * bdrv_a_allow_b() is asymmetric and we should check each pair in both
2211 QLIST_FOREACH(a
, &bs
->parents
, next_parent
) {
2212 QLIST_FOREACH(b
, &bs
->parents
, next_parent
) {
2217 if (!bdrv_a_allow_b(a
, b
, errp
)) {
2226 static void bdrv_child_perm(BlockDriverState
*bs
, BlockDriverState
*child_bs
,
2227 BdrvChild
*c
, BdrvChildRole role
,
2228 BlockReopenQueue
*reopen_queue
,
2229 uint64_t parent_perm
, uint64_t parent_shared
,
2230 uint64_t *nperm
, uint64_t *nshared
)
2232 assert(bs
->drv
&& bs
->drv
->bdrv_child_perm
);
2233 GLOBAL_STATE_CODE();
2234 bs
->drv
->bdrv_child_perm(bs
, c
, role
, reopen_queue
,
2235 parent_perm
, parent_shared
,
2237 /* TODO Take force_share from reopen_queue */
2238 if (child_bs
&& child_bs
->force_share
) {
2239 *nshared
= BLK_PERM_ALL
;
2244 * Adds the whole subtree of @bs (including @bs itself) to the @list (except for
2245 * nodes that are already in the @list, of course) so that final list is
2246 * topologically sorted. Return the result (GSList @list object is updated, so
2247 * don't use old reference after function call).
2249 * On function start @list must be already topologically sorted and for any node
2250 * in the @list the whole subtree of the node must be in the @list as well. The
2251 * simplest way to satisfy this criteria: use only result of
2252 * bdrv_topological_dfs() or NULL as @list parameter.
2254 static GSList
*bdrv_topological_dfs(GSList
*list
, GHashTable
*found
,
2255 BlockDriverState
*bs
)
2258 g_autoptr(GHashTable
) local_found
= NULL
;
2260 GLOBAL_STATE_CODE();
2264 found
= local_found
= g_hash_table_new(NULL
, NULL
);
2267 if (g_hash_table_contains(found
, bs
)) {
2270 g_hash_table_add(found
, bs
);
2272 QLIST_FOREACH(child
, &bs
->children
, next
) {
2273 list
= bdrv_topological_dfs(list
, found
, child
->bs
);
2276 return g_slist_prepend(list
, bs
);
2279 typedef struct BdrvChildSetPermState
{
2282 uint64_t old_shared_perm
;
2283 } BdrvChildSetPermState
;
2285 static void bdrv_child_set_perm_abort(void *opaque
)
2287 BdrvChildSetPermState
*s
= opaque
;
2289 GLOBAL_STATE_CODE();
2291 s
->child
->perm
= s
->old_perm
;
2292 s
->child
->shared_perm
= s
->old_shared_perm
;
2295 static TransactionActionDrv bdrv_child_set_pem_drv
= {
2296 .abort
= bdrv_child_set_perm_abort
,
2300 static void bdrv_child_set_perm(BdrvChild
*c
, uint64_t perm
,
2301 uint64_t shared
, Transaction
*tran
)
2303 BdrvChildSetPermState
*s
= g_new(BdrvChildSetPermState
, 1);
2304 GLOBAL_STATE_CODE();
2306 *s
= (BdrvChildSetPermState
) {
2308 .old_perm
= c
->perm
,
2309 .old_shared_perm
= c
->shared_perm
,
2313 c
->shared_perm
= shared
;
2315 tran_add(tran
, &bdrv_child_set_pem_drv
, s
);
2318 static void bdrv_drv_set_perm_commit(void *opaque
)
2320 BlockDriverState
*bs
= opaque
;
2321 uint64_t cumulative_perms
, cumulative_shared_perms
;
2322 GLOBAL_STATE_CODE();
2324 if (bs
->drv
->bdrv_set_perm
) {
2325 bdrv_get_cumulative_perm(bs
, &cumulative_perms
,
2326 &cumulative_shared_perms
);
2327 bs
->drv
->bdrv_set_perm(bs
, cumulative_perms
, cumulative_shared_perms
);
2331 static void bdrv_drv_set_perm_abort(void *opaque
)
2333 BlockDriverState
*bs
= opaque
;
2334 GLOBAL_STATE_CODE();
2336 if (bs
->drv
->bdrv_abort_perm_update
) {
2337 bs
->drv
->bdrv_abort_perm_update(bs
);
2341 TransactionActionDrv bdrv_drv_set_perm_drv
= {
2342 .abort
= bdrv_drv_set_perm_abort
,
2343 .commit
= bdrv_drv_set_perm_commit
,
2346 static int bdrv_drv_set_perm(BlockDriverState
*bs
, uint64_t perm
,
2347 uint64_t shared_perm
, Transaction
*tran
,
2350 GLOBAL_STATE_CODE();
2355 if (bs
->drv
->bdrv_check_perm
) {
2356 int ret
= bs
->drv
->bdrv_check_perm(bs
, perm
, shared_perm
, errp
);
2363 tran_add(tran
, &bdrv_drv_set_perm_drv
, bs
);
2369 typedef struct BdrvReplaceChildState
{
2371 BlockDriverState
*old_bs
;
2372 } BdrvReplaceChildState
;
2374 static void bdrv_replace_child_commit(void *opaque
)
2376 BdrvReplaceChildState
*s
= opaque
;
2377 GLOBAL_STATE_CODE();
2379 bdrv_unref(s
->old_bs
);
2382 static void bdrv_replace_child_abort(void *opaque
)
2384 BdrvReplaceChildState
*s
= opaque
;
2385 BlockDriverState
*new_bs
= s
->child
->bs
;
2387 GLOBAL_STATE_CODE();
2388 /* old_bs reference is transparently moved from @s to @s->child */
2389 if (!s
->child
->bs
) {
2391 * The parents were undrained when removing old_bs from the child. New
2392 * requests can't have been made, though, because the child was empty.
2394 * TODO Make bdrv_replace_child_noperm() transactionable to avoid
2395 * undraining the parent in the first place. Once this is done, having
2396 * new_bs drained when calling bdrv_replace_child_tran() is not a
2397 * requirement any more.
2399 bdrv_parent_drained_begin_single(s
->child
);
2400 assert(!bdrv_parent_drained_poll_single(s
->child
));
2402 assert(s
->child
->quiesced_parent
);
2403 bdrv_replace_child_noperm(s
->child
, s
->old_bs
);
2407 static TransactionActionDrv bdrv_replace_child_drv
= {
2408 .commit
= bdrv_replace_child_commit
,
2409 .abort
= bdrv_replace_child_abort
,
2414 * bdrv_replace_child_tran
2416 * Note: real unref of old_bs is done only on commit.
2418 * Both @child->bs and @new_bs (if non-NULL) must be drained. @new_bs must be
2419 * kept drained until the transaction is completed.
2421 * The function doesn't update permissions, caller is responsible for this.
2423 static void bdrv_replace_child_tran(BdrvChild
*child
, BlockDriverState
*new_bs
,
2426 BdrvReplaceChildState
*s
= g_new(BdrvReplaceChildState
, 1);
2428 assert(child
->quiesced_parent
);
2429 assert(!new_bs
|| new_bs
->quiesce_counter
);
2431 *s
= (BdrvReplaceChildState
) {
2433 .old_bs
= child
->bs
,
2435 tran_add(tran
, &bdrv_replace_child_drv
, s
);
2440 bdrv_replace_child_noperm(child
, new_bs
);
2441 /* old_bs reference is transparently moved from @child to @s */
2445 * Refresh permissions in @bs subtree. The function is intended to be called
2446 * after some graph modification that was done without permission update.
2448 static int bdrv_node_refresh_perm(BlockDriverState
*bs
, BlockReopenQueue
*q
,
2449 Transaction
*tran
, Error
**errp
)
2451 BlockDriver
*drv
= bs
->drv
;
2454 uint64_t cumulative_perms
, cumulative_shared_perms
;
2455 GLOBAL_STATE_CODE();
2457 bdrv_get_cumulative_perm(bs
, &cumulative_perms
, &cumulative_shared_perms
);
2459 /* Write permissions never work with read-only images */
2460 if ((cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) &&
2461 !bdrv_is_writable_after_reopen(bs
, q
))
2463 if (!bdrv_is_writable_after_reopen(bs
, NULL
)) {
2464 error_setg(errp
, "Block node is read-only");
2466 error_setg(errp
, "Read-only block node '%s' cannot support "
2467 "read-write users", bdrv_get_node_name(bs
));
2474 * Unaligned requests will automatically be aligned to bl.request_alignment
2475 * and without RESIZE we can't extend requests to write to space beyond the
2476 * end of the image, so it's required that the image size is aligned.
2478 if ((cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) &&
2479 !(cumulative_perms
& BLK_PERM_RESIZE
))
2481 if ((bs
->total_sectors
* BDRV_SECTOR_SIZE
) % bs
->bl
.request_alignment
) {
2482 error_setg(errp
, "Cannot get 'write' permission without 'resize': "
2483 "Image size is not a multiple of request "
2489 /* Check this node */
2494 ret
= bdrv_drv_set_perm(bs
, cumulative_perms
, cumulative_shared_perms
, tran
,
2500 /* Drivers that never have children can omit .bdrv_child_perm() */
2501 if (!drv
->bdrv_child_perm
) {
2502 assert(QLIST_EMPTY(&bs
->children
));
2506 /* Check all children */
2507 QLIST_FOREACH(c
, &bs
->children
, next
) {
2508 uint64_t cur_perm
, cur_shared
;
2510 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, q
,
2511 cumulative_perms
, cumulative_shared_perms
,
2512 &cur_perm
, &cur_shared
);
2513 bdrv_child_set_perm(c
, cur_perm
, cur_shared
, tran
);
2520 * @list is a product of bdrv_topological_dfs() (may be called several times) -
2521 * a topologically sorted subgraph.
2523 static int bdrv_do_refresh_perms(GSList
*list
, BlockReopenQueue
*q
,
2524 Transaction
*tran
, Error
**errp
)
2527 BlockDriverState
*bs
;
2528 GLOBAL_STATE_CODE();
2530 for ( ; list
; list
= list
->next
) {
2533 if (bdrv_parent_perms_conflict(bs
, errp
)) {
2537 ret
= bdrv_node_refresh_perm(bs
, q
, tran
, errp
);
2547 * @list is any list of nodes. List is completed by all subtrees and
2548 * topologically sorted. It's not a problem if some node occurs in the @list
2551 static int bdrv_list_refresh_perms(GSList
*list
, BlockReopenQueue
*q
,
2552 Transaction
*tran
, Error
**errp
)
2554 g_autoptr(GHashTable
) found
= g_hash_table_new(NULL
, NULL
);
2555 g_autoptr(GSList
) refresh_list
= NULL
;
2557 for ( ; list
; list
= list
->next
) {
2558 refresh_list
= bdrv_topological_dfs(refresh_list
, found
, list
->data
);
2561 return bdrv_do_refresh_perms(refresh_list
, q
, tran
, errp
);
2564 void bdrv_get_cumulative_perm(BlockDriverState
*bs
, uint64_t *perm
,
2565 uint64_t *shared_perm
)
2568 uint64_t cumulative_perms
= 0;
2569 uint64_t cumulative_shared_perms
= BLK_PERM_ALL
;
2571 GLOBAL_STATE_CODE();
2573 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
2574 cumulative_perms
|= c
->perm
;
2575 cumulative_shared_perms
&= c
->shared_perm
;
2578 *perm
= cumulative_perms
;
2579 *shared_perm
= cumulative_shared_perms
;
2582 char *bdrv_perm_names(uint64_t perm
)
2588 { BLK_PERM_CONSISTENT_READ
, "consistent read" },
2589 { BLK_PERM_WRITE
, "write" },
2590 { BLK_PERM_WRITE_UNCHANGED
, "write unchanged" },
2591 { BLK_PERM_RESIZE
, "resize" },
2595 GString
*result
= g_string_sized_new(30);
2596 struct perm_name
*p
;
2598 for (p
= permissions
; p
->name
; p
++) {
2599 if (perm
& p
->perm
) {
2600 if (result
->len
> 0) {
2601 g_string_append(result
, ", ");
2603 g_string_append(result
, p
->name
);
2607 return g_string_free(result
, FALSE
);
2611 /* @tran is allowed to be NULL. In this case no rollback is possible */
2612 static int bdrv_refresh_perms(BlockDriverState
*bs
, Transaction
*tran
,
2616 Transaction
*local_tran
= NULL
;
2617 g_autoptr(GSList
) list
= bdrv_topological_dfs(NULL
, NULL
, bs
);
2618 GLOBAL_STATE_CODE();
2621 tran
= local_tran
= tran_new();
2624 ret
= bdrv_do_refresh_perms(list
, NULL
, tran
, errp
);
2627 tran_finalize(local_tran
, ret
);
2633 int bdrv_child_try_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
,
2636 Error
*local_err
= NULL
;
2637 Transaction
*tran
= tran_new();
2640 GLOBAL_STATE_CODE();
2642 bdrv_child_set_perm(c
, perm
, shared
, tran
);
2644 ret
= bdrv_refresh_perms(c
->bs
, tran
, &local_err
);
2646 tran_finalize(tran
, ret
);
2649 if ((perm
& ~c
->perm
) || (c
->shared_perm
& ~shared
)) {
2650 /* tighten permissions */
2651 error_propagate(errp
, local_err
);
2654 * Our caller may intend to only loosen restrictions and
2655 * does not expect this function to fail. Errors are not
2656 * fatal in such a case, so we can just hide them from our
2659 error_free(local_err
);
2667 int bdrv_child_refresh_perms(BlockDriverState
*bs
, BdrvChild
*c
, Error
**errp
)
2669 uint64_t parent_perms
, parent_shared
;
2670 uint64_t perms
, shared
;
2672 GLOBAL_STATE_CODE();
2674 bdrv_get_cumulative_perm(bs
, &parent_perms
, &parent_shared
);
2675 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, NULL
,
2676 parent_perms
, parent_shared
, &perms
, &shared
);
2678 return bdrv_child_try_set_perm(c
, perms
, shared
, errp
);
2682 * Default implementation for .bdrv_child_perm() for block filters:
2683 * Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED, and RESIZE to the
2686 static void bdrv_filter_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2688 BlockReopenQueue
*reopen_queue
,
2689 uint64_t perm
, uint64_t shared
,
2690 uint64_t *nperm
, uint64_t *nshared
)
2692 GLOBAL_STATE_CODE();
2693 *nperm
= perm
& DEFAULT_PERM_PASSTHROUGH
;
2694 *nshared
= (shared
& DEFAULT_PERM_PASSTHROUGH
) | DEFAULT_PERM_UNCHANGED
;
2697 static void bdrv_default_perms_for_cow(BlockDriverState
*bs
, BdrvChild
*c
,
2699 BlockReopenQueue
*reopen_queue
,
2700 uint64_t perm
, uint64_t shared
,
2701 uint64_t *nperm
, uint64_t *nshared
)
2703 assert(role
& BDRV_CHILD_COW
);
2704 GLOBAL_STATE_CODE();
2707 * We want consistent read from backing files if the parent needs it.
2708 * No other operations are performed on backing files.
2710 perm
&= BLK_PERM_CONSISTENT_READ
;
2713 * If the parent can deal with changing data, we're okay with a
2714 * writable and resizable backing file.
2715 * TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too?
2717 if (shared
& BLK_PERM_WRITE
) {
2718 shared
= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2723 shared
|= BLK_PERM_CONSISTENT_READ
| BLK_PERM_WRITE_UNCHANGED
;
2725 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
2726 shared
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2733 static void bdrv_default_perms_for_storage(BlockDriverState
*bs
, BdrvChild
*c
,
2735 BlockReopenQueue
*reopen_queue
,
2736 uint64_t perm
, uint64_t shared
,
2737 uint64_t *nperm
, uint64_t *nshared
)
2741 GLOBAL_STATE_CODE();
2742 assert(role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_DATA
));
2744 flags
= bdrv_reopen_get_flags(reopen_queue
, bs
);
2747 * Apart from the modifications below, the same permissions are
2748 * forwarded and left alone as for filters
2750 bdrv_filter_default_perms(bs
, c
, role
, reopen_queue
,
2751 perm
, shared
, &perm
, &shared
);
2753 if (role
& BDRV_CHILD_METADATA
) {
2754 /* Format drivers may touch metadata even if the guest doesn't write */
2755 if (bdrv_is_writable_after_reopen(bs
, reopen_queue
)) {
2756 perm
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2760 * bs->file always needs to be consistent because of the
2761 * metadata. We can never allow other users to resize or write
2764 if (!(flags
& BDRV_O_NO_IO
)) {
2765 perm
|= BLK_PERM_CONSISTENT_READ
;
2767 shared
&= ~(BLK_PERM_WRITE
| BLK_PERM_RESIZE
);
2770 if (role
& BDRV_CHILD_DATA
) {
2772 * Technically, everything in this block is a subset of the
2773 * BDRV_CHILD_METADATA path taken above, and so this could
2774 * be an "else if" branch. However, that is not obvious, and
2775 * this function is not performance critical, therefore we let
2776 * this be an independent "if".
2780 * We cannot allow other users to resize the file because the
2781 * format driver might have some assumptions about the size
2782 * (e.g. because it is stored in metadata, or because the file
2783 * is split into fixed-size data files).
2785 shared
&= ~BLK_PERM_RESIZE
;
2788 * WRITE_UNCHANGED often cannot be performed as such on the
2789 * data file. For example, the qcow2 driver may still need to
2790 * write copied clusters on copy-on-read.
2792 if (perm
& BLK_PERM_WRITE_UNCHANGED
) {
2793 perm
|= BLK_PERM_WRITE
;
2797 * If the data file is written to, the format driver may
2798 * expect to be able to resize it by writing beyond the EOF.
2800 if (perm
& BLK_PERM_WRITE
) {
2801 perm
|= BLK_PERM_RESIZE
;
2805 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
2806 shared
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2813 void bdrv_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2814 BdrvChildRole role
, BlockReopenQueue
*reopen_queue
,
2815 uint64_t perm
, uint64_t shared
,
2816 uint64_t *nperm
, uint64_t *nshared
)
2818 GLOBAL_STATE_CODE();
2819 if (role
& BDRV_CHILD_FILTERED
) {
2820 assert(!(role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
|
2822 bdrv_filter_default_perms(bs
, c
, role
, reopen_queue
,
2823 perm
, shared
, nperm
, nshared
);
2824 } else if (role
& BDRV_CHILD_COW
) {
2825 assert(!(role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
)));
2826 bdrv_default_perms_for_cow(bs
, c
, role
, reopen_queue
,
2827 perm
, shared
, nperm
, nshared
);
2828 } else if (role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_DATA
)) {
2829 bdrv_default_perms_for_storage(bs
, c
, role
, reopen_queue
,
2830 perm
, shared
, nperm
, nshared
);
2832 g_assert_not_reached();
2836 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm
)
2838 static const uint64_t permissions
[] = {
2839 [BLOCK_PERMISSION_CONSISTENT_READ
] = BLK_PERM_CONSISTENT_READ
,
2840 [BLOCK_PERMISSION_WRITE
] = BLK_PERM_WRITE
,
2841 [BLOCK_PERMISSION_WRITE_UNCHANGED
] = BLK_PERM_WRITE_UNCHANGED
,
2842 [BLOCK_PERMISSION_RESIZE
] = BLK_PERM_RESIZE
,
2845 QEMU_BUILD_BUG_ON(ARRAY_SIZE(permissions
) != BLOCK_PERMISSION__MAX
);
2846 QEMU_BUILD_BUG_ON(1UL << ARRAY_SIZE(permissions
) != BLK_PERM_ALL
+ 1);
2848 assert(qapi_perm
< BLOCK_PERMISSION__MAX
);
2850 return permissions
[qapi_perm
];
2854 * Replaces the node that a BdrvChild points to without updating permissions.
2856 * If @new_bs is non-NULL, the parent of @child must already be drained through
2859 static void bdrv_replace_child_noperm(BdrvChild
*child
,
2860 BlockDriverState
*new_bs
)
2862 BlockDriverState
*old_bs
= child
->bs
;
2863 int new_bs_quiesce_counter
;
2865 assert(!child
->frozen
);
2868 * If we want to change the BdrvChild to point to a drained node as its new
2869 * child->bs, we need to make sure that its new parent is drained, too. In
2870 * other words, either child->quiesce_parent must already be true or we must
2871 * be able to set it and keep the parent's quiesce_counter consistent with
2872 * that, but without polling or starting new requests (this function
2873 * guarantees that it doesn't poll, and starting new requests would be
2874 * against the invariants of drain sections).
2876 * To keep things simple, we pick the first option (child->quiesce_parent
2877 * must already be true). We also generalise the rule a bit to make it
2878 * easier to verify in callers and more likely to be covered in test cases:
2879 * The parent must be quiesced through this child even if new_bs isn't
2880 * currently drained.
2882 * The only exception is for callers that always pass new_bs == NULL. In
2883 * this case, we obviously never need to consider the case of a drained
2884 * new_bs, so we can keep the callers simpler by allowing them not to drain
2887 assert(!new_bs
|| child
->quiesced_parent
);
2888 assert(old_bs
!= new_bs
);
2889 GLOBAL_STATE_CODE();
2891 if (old_bs
&& new_bs
) {
2892 assert(bdrv_get_aio_context(old_bs
) == bdrv_get_aio_context(new_bs
));
2895 /* TODO Pull this up into the callers to avoid polling here */
2896 bdrv_graph_wrlock();
2898 if (child
->klass
->detach
) {
2899 child
->klass
->detach(child
);
2901 QLIST_REMOVE(child
, next_parent
);
2907 QLIST_INSERT_HEAD(&new_bs
->parents
, child
, next_parent
);
2908 if (child
->klass
->attach
) {
2909 child
->klass
->attach(child
);
2912 bdrv_graph_wrunlock();
2915 * If the parent was drained through this BdrvChild previously, but new_bs
2916 * is not drained, allow requests to come in only after the new node has
2919 new_bs_quiesce_counter
= (new_bs
? new_bs
->quiesce_counter
: 0);
2920 if (!new_bs_quiesce_counter
&& child
->quiesced_parent
) {
2921 bdrv_parent_drained_end_single(child
);
2926 * Free the given @child.
2928 * The child must be empty (i.e. `child->bs == NULL`) and it must be
2929 * unused (i.e. not in a children list).
2931 static void bdrv_child_free(BdrvChild
*child
)
2934 GLOBAL_STATE_CODE();
2935 assert(!child
->next
.le_prev
); /* not in children list */
2937 g_free(child
->name
);
2941 typedef struct BdrvAttachChildCommonState
{
2943 AioContext
*old_parent_ctx
;
2944 AioContext
*old_child_ctx
;
2945 } BdrvAttachChildCommonState
;
2947 static void bdrv_attach_child_common_abort(void *opaque
)
2949 BdrvAttachChildCommonState
*s
= opaque
;
2950 BlockDriverState
*bs
= s
->child
->bs
;
2952 GLOBAL_STATE_CODE();
2953 bdrv_replace_child_noperm(s
->child
, NULL
);
2955 if (bdrv_get_aio_context(bs
) != s
->old_child_ctx
) {
2956 bdrv_try_change_aio_context(bs
, s
->old_child_ctx
, NULL
, &error_abort
);
2959 if (bdrv_child_get_parent_aio_context(s
->child
) != s
->old_parent_ctx
) {
2961 GHashTable
*visited
;
2966 /* No need to visit `child`, because it has been detached already */
2967 visited
= g_hash_table_new(NULL
, NULL
);
2968 ret
= s
->child
->klass
->change_aio_ctx(s
->child
, s
->old_parent_ctx
,
2969 visited
, tran
, &error_abort
);
2970 g_hash_table_destroy(visited
);
2972 /* transaction is supposed to always succeed */
2973 assert(ret
== true);
2978 bdrv_child_free(s
->child
);
2981 static TransactionActionDrv bdrv_attach_child_common_drv
= {
2982 .abort
= bdrv_attach_child_common_abort
,
2987 * Common part of attaching bdrv child to bs or to blk or to job
2989 * Function doesn't update permissions, caller is responsible for this.
2991 * Returns new created child.
2993 * The caller must hold the AioContext lock for @child_bs. Both @parent_bs and
2994 * @child_bs can move to a different AioContext in this function. Callers must
2995 * make sure that their AioContext locking is still correct after this.
2997 static BdrvChild
*bdrv_attach_child_common(BlockDriverState
*child_bs
,
2998 const char *child_name
,
2999 const BdrvChildClass
*child_class
,
3000 BdrvChildRole child_role
,
3001 uint64_t perm
, uint64_t shared_perm
,
3003 Transaction
*tran
, Error
**errp
)
3005 BdrvChild
*new_child
;
3006 AioContext
*parent_ctx
, *new_child_ctx
;
3007 AioContext
*child_ctx
= bdrv_get_aio_context(child_bs
);
3009 assert(child_class
->get_parent_desc
);
3010 GLOBAL_STATE_CODE();
3012 new_child
= g_new(BdrvChild
, 1);
3013 *new_child
= (BdrvChild
) {
3015 .name
= g_strdup(child_name
),
3016 .klass
= child_class
,
3019 .shared_perm
= shared_perm
,
3024 * If the AioContexts don't match, first try to move the subtree of
3025 * child_bs into the AioContext of the new parent. If this doesn't work,
3026 * try moving the parent into the AioContext of child_bs instead.
3028 parent_ctx
= bdrv_child_get_parent_aio_context(new_child
);
3029 if (child_ctx
!= parent_ctx
) {
3030 Error
*local_err
= NULL
;
3031 int ret
= bdrv_try_change_aio_context(child_bs
, parent_ctx
, NULL
,
3034 if (ret
< 0 && child_class
->change_aio_ctx
) {
3035 Transaction
*tran
= tran_new();
3036 GHashTable
*visited
= g_hash_table_new(NULL
, NULL
);
3039 g_hash_table_add(visited
, new_child
);
3040 ret_child
= child_class
->change_aio_ctx(new_child
, child_ctx
,
3041 visited
, tran
, NULL
);
3042 if (ret_child
== true) {
3043 error_free(local_err
);
3046 tran_finalize(tran
, ret_child
== true ? 0 : -1);
3047 g_hash_table_destroy(visited
);
3051 error_propagate(errp
, local_err
);
3052 bdrv_child_free(new_child
);
3057 new_child_ctx
= bdrv_get_aio_context(child_bs
);
3058 if (new_child_ctx
!= child_ctx
) {
3059 aio_context_release(child_ctx
);
3060 aio_context_acquire(new_child_ctx
);
3065 * Let every new BdrvChild start with a drained parent. Inserting the child
3066 * in the graph with bdrv_replace_child_noperm() will undrain it if
3067 * @child_bs is not drained.
3069 * The child was only just created and is not yet visible in global state
3070 * until bdrv_replace_child_noperm() inserts it into the graph, so nobody
3071 * could have sent requests and polling is not necessary.
3073 * Note that this means that the parent isn't fully drained yet, we only
3074 * stop new requests from coming in. This is fine, we don't care about the
3075 * old requests here, they are not for this child. If another place enters a
3076 * drain section for the same parent, but wants it to be fully quiesced, it
3077 * will not run most of the the code in .drained_begin() again (which is not
3078 * a problem, we already did this), but it will still poll until the parent
3079 * is fully quiesced, so it will not be negatively affected either.
3081 bdrv_parent_drained_begin_single(new_child
);
3082 bdrv_replace_child_noperm(new_child
, child_bs
);
3084 BdrvAttachChildCommonState
*s
= g_new(BdrvAttachChildCommonState
, 1);
3085 *s
= (BdrvAttachChildCommonState
) {
3087 .old_parent_ctx
= parent_ctx
,
3088 .old_child_ctx
= child_ctx
,
3090 tran_add(tran
, &bdrv_attach_child_common_drv
, s
);
3092 if (new_child_ctx
!= child_ctx
) {
3093 aio_context_release(new_child_ctx
);
3094 aio_context_acquire(child_ctx
);
3101 * Function doesn't update permissions, caller is responsible for this.
3103 * The caller must hold the AioContext lock for @child_bs. Both @parent_bs and
3104 * @child_bs can move to a different AioContext in this function. Callers must
3105 * make sure that their AioContext locking is still correct after this.
3107 static BdrvChild
*bdrv_attach_child_noperm(BlockDriverState
*parent_bs
,
3108 BlockDriverState
*child_bs
,
3109 const char *child_name
,
3110 const BdrvChildClass
*child_class
,
3111 BdrvChildRole child_role
,
3115 uint64_t perm
, shared_perm
;
3117 assert(parent_bs
->drv
);
3118 GLOBAL_STATE_CODE();
3120 if (bdrv_recurse_has_child(child_bs
, parent_bs
)) {
3121 error_setg(errp
, "Making '%s' a %s child of '%s' would create a cycle",
3122 child_bs
->node_name
, child_name
, parent_bs
->node_name
);
3126 bdrv_get_cumulative_perm(parent_bs
, &perm
, &shared_perm
);
3127 bdrv_child_perm(parent_bs
, child_bs
, NULL
, child_role
, NULL
,
3128 perm
, shared_perm
, &perm
, &shared_perm
);
3130 return bdrv_attach_child_common(child_bs
, child_name
, child_class
,
3131 child_role
, perm
, shared_perm
, parent_bs
,
3136 * This function steals the reference to child_bs from the caller.
3137 * That reference is later dropped by bdrv_root_unref_child().
3139 * On failure NULL is returned, errp is set and the reference to
3140 * child_bs is also dropped.
3142 * The caller must hold the AioContext lock @child_bs, but not that of @ctx
3143 * (unless @child_bs is already in @ctx).
3145 BdrvChild
*bdrv_root_attach_child(BlockDriverState
*child_bs
,
3146 const char *child_name
,
3147 const BdrvChildClass
*child_class
,
3148 BdrvChildRole child_role
,
3149 uint64_t perm
, uint64_t shared_perm
,
3150 void *opaque
, Error
**errp
)
3154 Transaction
*tran
= tran_new();
3156 GLOBAL_STATE_CODE();
3158 child
= bdrv_attach_child_common(child_bs
, child_name
, child_class
,
3159 child_role
, perm
, shared_perm
, opaque
,
3166 ret
= bdrv_refresh_perms(child_bs
, tran
, errp
);
3169 tran_finalize(tran
, ret
);
3171 bdrv_unref(child_bs
);
3173 return ret
< 0 ? NULL
: child
;
3177 * This function transfers the reference to child_bs from the caller
3178 * to parent_bs. That reference is later dropped by parent_bs on
3179 * bdrv_close() or if someone calls bdrv_unref_child().
3181 * On failure NULL is returned, errp is set and the reference to
3182 * child_bs is also dropped.
3184 * If @parent_bs and @child_bs are in different AioContexts, the caller must
3185 * hold the AioContext lock for @child_bs, but not for @parent_bs.
3187 BdrvChild
*bdrv_attach_child(BlockDriverState
*parent_bs
,
3188 BlockDriverState
*child_bs
,
3189 const char *child_name
,
3190 const BdrvChildClass
*child_class
,
3191 BdrvChildRole child_role
,
3196 Transaction
*tran
= tran_new();
3198 GLOBAL_STATE_CODE();
3200 child
= bdrv_attach_child_noperm(parent_bs
, child_bs
, child_name
,
3201 child_class
, child_role
, tran
, errp
);
3207 ret
= bdrv_refresh_perms(parent_bs
, tran
, errp
);
3213 tran_finalize(tran
, ret
);
3215 bdrv_unref(child_bs
);
3217 return ret
< 0 ? NULL
: child
;
3220 /* Callers must ensure that child->frozen is false. */
3221 void bdrv_root_unref_child(BdrvChild
*child
)
3223 BlockDriverState
*child_bs
= child
->bs
;
3225 GLOBAL_STATE_CODE();
3226 bdrv_replace_child_noperm(child
, NULL
);
3227 bdrv_child_free(child
);
3231 * Update permissions for old node. We're just taking a parent away, so
3232 * we're loosening restrictions. Errors of permission update are not
3233 * fatal in this case, ignore them.
3235 bdrv_refresh_perms(child_bs
, NULL
, NULL
);
3238 * When the parent requiring a non-default AioContext is removed, the
3239 * node moves back to the main AioContext
3241 bdrv_try_change_aio_context(child_bs
, qemu_get_aio_context(), NULL
,
3245 bdrv_unref(child_bs
);
3248 typedef struct BdrvSetInheritsFrom
{
3249 BlockDriverState
*bs
;
3250 BlockDriverState
*old_inherits_from
;
3251 } BdrvSetInheritsFrom
;
3253 static void bdrv_set_inherits_from_abort(void *opaque
)
3255 BdrvSetInheritsFrom
*s
= opaque
;
3257 s
->bs
->inherits_from
= s
->old_inherits_from
;
3260 static TransactionActionDrv bdrv_set_inherits_from_drv
= {
3261 .abort
= bdrv_set_inherits_from_abort
,
3265 /* @tran is allowed to be NULL. In this case no rollback is possible */
3266 static void bdrv_set_inherits_from(BlockDriverState
*bs
,
3267 BlockDriverState
*new_inherits_from
,
3271 BdrvSetInheritsFrom
*s
= g_new(BdrvSetInheritsFrom
, 1);
3273 *s
= (BdrvSetInheritsFrom
) {
3275 .old_inherits_from
= bs
->inherits_from
,
3278 tran_add(tran
, &bdrv_set_inherits_from_drv
, s
);
3281 bs
->inherits_from
= new_inherits_from
;
3285 * Clear all inherits_from pointers from children and grandchildren of
3286 * @root that point to @root, where necessary.
3287 * @tran is allowed to be NULL. In this case no rollback is possible
3289 static void bdrv_unset_inherits_from(BlockDriverState
*root
, BdrvChild
*child
,
3294 if (child
->bs
->inherits_from
== root
) {
3296 * Remove inherits_from only when the last reference between root and
3297 * child->bs goes away.
3299 QLIST_FOREACH(c
, &root
->children
, next
) {
3300 if (c
!= child
&& c
->bs
== child
->bs
) {
3305 bdrv_set_inherits_from(child
->bs
, NULL
, tran
);
3309 QLIST_FOREACH(c
, &child
->bs
->children
, next
) {
3310 bdrv_unset_inherits_from(root
, c
, tran
);
3314 /* Callers must ensure that child->frozen is false. */
3315 void bdrv_unref_child(BlockDriverState
*parent
, BdrvChild
*child
)
3317 GLOBAL_STATE_CODE();
3318 if (child
== NULL
) {
3322 bdrv_unset_inherits_from(parent
, child
, NULL
);
3323 bdrv_root_unref_child(child
);
3327 static void bdrv_parent_cb_change_media(BlockDriverState
*bs
, bool load
)
3330 GLOBAL_STATE_CODE();
3331 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
3332 if (c
->klass
->change_media
) {
3333 c
->klass
->change_media(c
, load
);
3338 /* Return true if you can reach parent going through child->inherits_from
3339 * recursively. If parent or child are NULL, return false */
3340 static bool bdrv_inherits_from_recursive(BlockDriverState
*child
,
3341 BlockDriverState
*parent
)
3343 while (child
&& child
!= parent
) {
3344 child
= child
->inherits_from
;
3347 return child
!= NULL
;
3351 * Return the BdrvChildRole for @bs's backing child. bs->backing is
3352 * mostly used for COW backing children (role = COW), but also for
3353 * filtered children (role = FILTERED | PRIMARY).
3355 static BdrvChildRole
bdrv_backing_role(BlockDriverState
*bs
)
3357 if (bs
->drv
&& bs
->drv
->is_filter
) {
3358 return BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
;
3360 return BDRV_CHILD_COW
;
3365 * Sets the bs->backing or bs->file link of a BDS. A new reference is created;
3366 * callers which don't need their own reference any more must call bdrv_unref().
3368 * Function doesn't update permissions, caller is responsible for this.
3370 * The caller must hold the AioContext lock for @child_bs. Both @parent_bs and
3371 * @child_bs can move to a different AioContext in this function. Callers must
3372 * make sure that their AioContext locking is still correct after this.
3374 static int bdrv_set_file_or_backing_noperm(BlockDriverState
*parent_bs
,
3375 BlockDriverState
*child_bs
,
3377 Transaction
*tran
, Error
**errp
)
3379 bool update_inherits_from
=
3380 bdrv_inherits_from_recursive(child_bs
, parent_bs
);
3381 BdrvChild
*child
= is_backing
? parent_bs
->backing
: parent_bs
->file
;
3384 GLOBAL_STATE_CODE();
3386 if (!parent_bs
->drv
) {
3388 * Node without drv is an object without a class :/. TODO: finally fix
3389 * qcow2 driver to never clear bs->drv and implement format corruption
3390 * handling in other way.
3392 error_setg(errp
, "Node corrupted");
3396 if (child
&& child
->frozen
) {
3397 error_setg(errp
, "Cannot change frozen '%s' link from '%s' to '%s'",
3398 child
->name
, parent_bs
->node_name
, child
->bs
->node_name
);
3402 if (is_backing
&& !parent_bs
->drv
->is_filter
&&
3403 !parent_bs
->drv
->supports_backing
)
3405 error_setg(errp
, "Driver '%s' of node '%s' does not support backing "
3406 "files", parent_bs
->drv
->format_name
, parent_bs
->node_name
);
3410 if (parent_bs
->drv
->is_filter
) {
3411 role
= BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
;
3412 } else if (is_backing
) {
3413 role
= BDRV_CHILD_COW
;
3416 * We only can use same role as it is in existing child. We don't have
3417 * infrastructure to determine role of file child in generic way
3420 error_setg(errp
, "Cannot set file child to format node without "
3428 bdrv_unset_inherits_from(parent_bs
, child
, tran
);
3429 bdrv_remove_child(child
, tran
);
3436 child
= bdrv_attach_child_noperm(parent_bs
, child_bs
,
3437 is_backing
? "backing" : "file",
3438 &child_of_bds
, role
,
3446 * If inherits_from pointed recursively to bs then let's update it to
3447 * point directly to bs (else it will become NULL).
3449 if (update_inherits_from
) {
3450 bdrv_set_inherits_from(child_bs
, parent_bs
, tran
);
3454 bdrv_graph_rdlock_main_loop();
3455 bdrv_refresh_limits(parent_bs
, tran
, NULL
);
3456 bdrv_graph_rdunlock_main_loop();
3462 * The caller must hold the AioContext lock for @backing_hd. Both @bs and
3463 * @backing_hd can move to a different AioContext in this function. Callers must
3464 * make sure that their AioContext locking is still correct after this.
3466 static int bdrv_set_backing_noperm(BlockDriverState
*bs
,
3467 BlockDriverState
*backing_hd
,
3468 Transaction
*tran
, Error
**errp
)
3470 GLOBAL_STATE_CODE();
3471 return bdrv_set_file_or_backing_noperm(bs
, backing_hd
, true, tran
, errp
);
3474 int bdrv_set_backing_hd_drained(BlockDriverState
*bs
,
3475 BlockDriverState
*backing_hd
,
3479 Transaction
*tran
= tran_new();
3481 GLOBAL_STATE_CODE();
3482 assert(bs
->quiesce_counter
> 0);
3484 ret
= bdrv_set_backing_noperm(bs
, backing_hd
, tran
, errp
);
3489 ret
= bdrv_refresh_perms(bs
, tran
, errp
);
3491 tran_finalize(tran
, ret
);
3495 int bdrv_set_backing_hd(BlockDriverState
*bs
, BlockDriverState
*backing_hd
,
3499 GLOBAL_STATE_CODE();
3501 bdrv_drained_begin(bs
);
3502 ret
= bdrv_set_backing_hd_drained(bs
, backing_hd
, errp
);
3503 bdrv_drained_end(bs
);
3509 * Opens the backing file for a BlockDriverState if not yet open
3511 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
3512 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
3513 * itself, all options starting with "${bdref_key}." are considered part of the
3516 * The caller must hold the main AioContext lock.
3518 * TODO Can this be unified with bdrv_open_image()?
3520 int bdrv_open_backing_file(BlockDriverState
*bs
, QDict
*parent_options
,
3521 const char *bdref_key
, Error
**errp
)
3523 char *backing_filename
= NULL
;
3524 char *bdref_key_dot
;
3525 const char *reference
= NULL
;
3527 bool implicit_backing
= false;
3528 BlockDriverState
*backing_hd
;
3529 AioContext
*backing_hd_ctx
;
3531 QDict
*tmp_parent_options
= NULL
;
3532 Error
*local_err
= NULL
;
3534 GLOBAL_STATE_CODE();
3536 if (bs
->backing
!= NULL
) {
3540 /* NULL means an empty set of options */
3541 if (parent_options
== NULL
) {
3542 tmp_parent_options
= qdict_new();
3543 parent_options
= tmp_parent_options
;
3546 bs
->open_flags
&= ~BDRV_O_NO_BACKING
;
3548 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
3549 qdict_extract_subqdict(parent_options
, &options
, bdref_key_dot
);
3550 g_free(bdref_key_dot
);
3553 * Caution: while qdict_get_try_str() is fine, getting non-string
3554 * types would require more care. When @parent_options come from
3555 * -blockdev or blockdev_add, its members are typed according to
3556 * the QAPI schema, but when they come from -drive, they're all
3559 reference
= qdict_get_try_str(parent_options
, bdref_key
);
3560 if (reference
|| qdict_haskey(options
, "file.filename")) {
3561 /* keep backing_filename NULL */
3562 } else if (bs
->backing_file
[0] == '\0' && qdict_size(options
) == 0) {
3563 qobject_unref(options
);
3566 if (qdict_size(options
) == 0) {
3567 /* If the user specifies options that do not modify the
3568 * backing file's behavior, we might still consider it the
3569 * implicit backing file. But it's easier this way, and
3570 * just specifying some of the backing BDS's options is
3571 * only possible with -drive anyway (otherwise the QAPI
3572 * schema forces the user to specify everything). */
3573 implicit_backing
= !strcmp(bs
->auto_backing_file
, bs
->backing_file
);
3576 backing_filename
= bdrv_get_full_backing_filename(bs
, &local_err
);
3579 error_propagate(errp
, local_err
);
3580 qobject_unref(options
);
3585 if (!bs
->drv
|| !bs
->drv
->supports_backing
) {
3587 error_setg(errp
, "Driver doesn't support backing files");
3588 qobject_unref(options
);
3593 bs
->backing_format
[0] != '\0' && !qdict_haskey(options
, "driver")) {
3594 qdict_put_str(options
, "driver", bs
->backing_format
);
3597 backing_hd
= bdrv_open_inherit(backing_filename
, reference
, options
, 0, bs
,
3598 &child_of_bds
, bdrv_backing_role(bs
), errp
);
3600 bs
->open_flags
|= BDRV_O_NO_BACKING
;
3601 error_prepend(errp
, "Could not open backing file: ");
3606 if (implicit_backing
) {
3607 bdrv_refresh_filename(backing_hd
);
3608 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
3609 backing_hd
->filename
);
3612 /* Hook up the backing file link; drop our reference, bs owns the
3613 * backing_hd reference now */
3614 backing_hd_ctx
= bdrv_get_aio_context(backing_hd
);
3615 aio_context_acquire(backing_hd_ctx
);
3616 ret
= bdrv_set_backing_hd(bs
, backing_hd
, errp
);
3617 bdrv_unref(backing_hd
);
3618 aio_context_release(backing_hd_ctx
);
3624 qdict_del(parent_options
, bdref_key
);
3627 g_free(backing_filename
);
3628 qobject_unref(tmp_parent_options
);
3632 static BlockDriverState
*
3633 bdrv_open_child_bs(const char *filename
, QDict
*options
, const char *bdref_key
,
3634 BlockDriverState
*parent
, const BdrvChildClass
*child_class
,
3635 BdrvChildRole child_role
, bool allow_none
, Error
**errp
)
3637 BlockDriverState
*bs
= NULL
;
3638 QDict
*image_options
;
3639 char *bdref_key_dot
;
3640 const char *reference
;
3642 assert(child_class
!= NULL
);
3644 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
3645 qdict_extract_subqdict(options
, &image_options
, bdref_key_dot
);
3646 g_free(bdref_key_dot
);
3649 * Caution: while qdict_get_try_str() is fine, getting non-string
3650 * types would require more care. When @options come from
3651 * -blockdev or blockdev_add, its members are typed according to
3652 * the QAPI schema, but when they come from -drive, they're all
3655 reference
= qdict_get_try_str(options
, bdref_key
);
3656 if (!filename
&& !reference
&& !qdict_size(image_options
)) {
3658 error_setg(errp
, "A block device must be specified for \"%s\"",
3661 qobject_unref(image_options
);
3665 bs
= bdrv_open_inherit(filename
, reference
, image_options
, 0,
3666 parent
, child_class
, child_role
, errp
);
3672 qdict_del(options
, bdref_key
);
3677 * Opens a disk image whose options are given as BlockdevRef in another block
3680 * If allow_none is true, no image will be opened if filename is false and no
3681 * BlockdevRef is given. NULL will be returned, but errp remains unset.
3683 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
3684 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
3685 * itself, all options starting with "${bdref_key}." are considered part of the
3688 * The BlockdevRef will be removed from the options QDict.
3690 * The caller must hold the lock of the main AioContext and no other AioContext.
3691 * @parent can move to a different AioContext in this function. Callers must
3692 * make sure that their AioContext locking is still correct after this.
3694 BdrvChild
*bdrv_open_child(const char *filename
,
3695 QDict
*options
, const char *bdref_key
,
3696 BlockDriverState
*parent
,
3697 const BdrvChildClass
*child_class
,
3698 BdrvChildRole child_role
,
3699 bool allow_none
, Error
**errp
)
3701 BlockDriverState
*bs
;
3705 GLOBAL_STATE_CODE();
3707 bs
= bdrv_open_child_bs(filename
, options
, bdref_key
, parent
, child_class
,
3708 child_role
, allow_none
, errp
);
3713 ctx
= bdrv_get_aio_context(bs
);
3714 aio_context_acquire(ctx
);
3715 child
= bdrv_attach_child(parent
, bs
, bdref_key
, child_class
, child_role
,
3717 aio_context_release(ctx
);
3723 * Wrapper on bdrv_open_child() for most popular case: open primary child of bs.
3725 * The caller must hold the lock of the main AioContext and no other AioContext.
3726 * @parent can move to a different AioContext in this function. Callers must
3727 * make sure that their AioContext locking is still correct after this.
3729 int bdrv_open_file_child(const char *filename
,
3730 QDict
*options
, const char *bdref_key
,
3731 BlockDriverState
*parent
, Error
**errp
)
3735 /* commit_top and mirror_top don't use this function */
3736 assert(!parent
->drv
->filtered_child_is_backing
);
3737 role
= parent
->drv
->is_filter
?
3738 (BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
) : BDRV_CHILD_IMAGE
;
3740 if (!bdrv_open_child(filename
, options
, bdref_key
, parent
,
3741 &child_of_bds
, role
, false, errp
))
3750 * TODO Future callers may need to specify parent/child_class in order for
3751 * option inheritance to work. Existing callers use it for the root node.
3753 BlockDriverState
*bdrv_open_blockdev_ref(BlockdevRef
*ref
, Error
**errp
)
3755 BlockDriverState
*bs
= NULL
;
3756 QObject
*obj
= NULL
;
3757 QDict
*qdict
= NULL
;
3758 const char *reference
= NULL
;
3761 GLOBAL_STATE_CODE();
3763 if (ref
->type
== QTYPE_QSTRING
) {
3764 reference
= ref
->u
.reference
;
3766 BlockdevOptions
*options
= &ref
->u
.definition
;
3767 assert(ref
->type
== QTYPE_QDICT
);
3769 v
= qobject_output_visitor_new(&obj
);
3770 visit_type_BlockdevOptions(v
, NULL
, &options
, &error_abort
);
3771 visit_complete(v
, &obj
);
3773 qdict
= qobject_to(QDict
, obj
);
3774 qdict_flatten(qdict
);
3776 /* bdrv_open_inherit() defaults to the values in bdrv_flags (for
3777 * compatibility with other callers) rather than what we want as the
3778 * real defaults. Apply the defaults here instead. */
3779 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_DIRECT
, "off");
3780 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_NO_FLUSH
, "off");
3781 qdict_set_default_str(qdict
, BDRV_OPT_READ_ONLY
, "off");
3782 qdict_set_default_str(qdict
, BDRV_OPT_AUTO_READ_ONLY
, "off");
3786 bs
= bdrv_open_inherit(NULL
, reference
, qdict
, 0, NULL
, NULL
, 0, errp
);
3793 static BlockDriverState
*bdrv_append_temp_snapshot(BlockDriverState
*bs
,
3795 QDict
*snapshot_options
,
3798 g_autofree
char *tmp_filename
= NULL
;
3800 QemuOpts
*opts
= NULL
;
3801 BlockDriverState
*bs_snapshot
= NULL
;
3802 AioContext
*ctx
= bdrv_get_aio_context(bs
);
3805 GLOBAL_STATE_CODE();
3807 /* if snapshot, we create a temporary backing file and open it
3808 instead of opening 'filename' directly */
3810 /* Get the required size from the image */
3811 aio_context_acquire(ctx
);
3812 total_size
= bdrv_getlength(bs
);
3813 aio_context_release(ctx
);
3815 if (total_size
< 0) {
3816 error_setg_errno(errp
, -total_size
, "Could not get image size");
3820 /* Create the temporary image */
3821 tmp_filename
= create_tmp_file(errp
);
3822 if (!tmp_filename
) {
3826 opts
= qemu_opts_create(bdrv_qcow2
.create_opts
, NULL
, 0,
3828 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, total_size
, &error_abort
);
3829 ret
= bdrv_create(&bdrv_qcow2
, tmp_filename
, opts
, errp
);
3830 qemu_opts_del(opts
);
3832 error_prepend(errp
, "Could not create temporary overlay '%s': ",
3837 /* Prepare options QDict for the temporary file */
3838 qdict_put_str(snapshot_options
, "file.driver", "file");
3839 qdict_put_str(snapshot_options
, "file.filename", tmp_filename
);
3840 qdict_put_str(snapshot_options
, "driver", "qcow2");
3842 bs_snapshot
= bdrv_open(NULL
, NULL
, snapshot_options
, flags
, errp
);
3843 snapshot_options
= NULL
;
3848 aio_context_acquire(ctx
);
3849 ret
= bdrv_append(bs_snapshot
, bs
, errp
);
3850 aio_context_release(ctx
);
3858 qobject_unref(snapshot_options
);
3863 * Opens a disk image (raw, qcow2, vmdk, ...)
3865 * options is a QDict of options to pass to the block drivers, or NULL for an
3866 * empty set of options. The reference to the QDict belongs to the block layer
3867 * after the call (even on failure), so if the caller intends to reuse the
3868 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
3870 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
3871 * If it is not NULL, the referenced BDS will be reused.
3873 * The reference parameter may be used to specify an existing block device which
3874 * should be opened. If specified, neither options nor a filename may be given,
3875 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
3877 * The caller must always hold the main AioContext lock.
3879 static BlockDriverState
* no_coroutine_fn
3880 bdrv_open_inherit(const char *filename
, const char *reference
, QDict
*options
,
3881 int flags
, BlockDriverState
*parent
,
3882 const BdrvChildClass
*child_class
, BdrvChildRole child_role
,
3886 BlockBackend
*file
= NULL
;
3887 BlockDriverState
*bs
;
3888 BlockDriver
*drv
= NULL
;
3890 const char *drvname
;
3891 const char *backing
;
3892 Error
*local_err
= NULL
;
3893 QDict
*snapshot_options
= NULL
;
3894 int snapshot_flags
= 0;
3895 AioContext
*ctx
= qemu_get_aio_context();
3897 assert(!child_class
|| !flags
);
3898 assert(!child_class
== !parent
);
3899 GLOBAL_STATE_CODE();
3900 assert(!qemu_in_coroutine());
3903 bool options_non_empty
= options
? qdict_size(options
) : false;
3904 qobject_unref(options
);
3906 if (filename
|| options_non_empty
) {
3907 error_setg(errp
, "Cannot reference an existing block device with "
3908 "additional options or a new filename");
3912 bs
= bdrv_lookup_bs(reference
, reference
, errp
);
3923 /* NULL means an empty set of options */
3924 if (options
== NULL
) {
3925 options
= qdict_new();
3928 /* json: syntax counts as explicit options, as if in the QDict */
3929 parse_json_protocol(options
, &filename
, &local_err
);
3934 bs
->explicit_options
= qdict_clone_shallow(options
);
3937 bool parent_is_format
;
3940 parent_is_format
= parent
->drv
->is_format
;
3943 * parent->drv is not set yet because this node is opened for
3944 * (potential) format probing. That means that @parent is going
3945 * to be a format node.
3947 parent_is_format
= true;
3950 bs
->inherits_from
= parent
;
3951 child_class
->inherit_options(child_role
, parent_is_format
,
3953 parent
->open_flags
, parent
->options
);
3956 ret
= bdrv_fill_options(&options
, filename
, &flags
, &local_err
);
3962 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
3963 * Caution: getting a boolean member of @options requires care.
3964 * When @options come from -blockdev or blockdev_add, members are
3965 * typed according to the QAPI schema, but when they come from
3966 * -drive, they're all QString.
3968 if (g_strcmp0(qdict_get_try_str(options
, BDRV_OPT_READ_ONLY
), "on") &&
3969 !qdict_get_try_bool(options
, BDRV_OPT_READ_ONLY
, false)) {
3970 flags
|= (BDRV_O_RDWR
| BDRV_O_ALLOW_RDWR
);
3972 flags
&= ~BDRV_O_RDWR
;
3975 if (flags
& BDRV_O_SNAPSHOT
) {
3976 snapshot_options
= qdict_new();
3977 bdrv_temp_snapshot_options(&snapshot_flags
, snapshot_options
,
3979 /* Let bdrv_backing_options() override "read-only" */
3980 qdict_del(options
, BDRV_OPT_READ_ONLY
);
3981 bdrv_inherited_options(BDRV_CHILD_COW
, true,
3982 &flags
, options
, flags
, options
);
3985 bs
->open_flags
= flags
;
3986 bs
->options
= options
;
3987 options
= qdict_clone_shallow(options
);
3989 /* Find the right image format driver */
3990 /* See cautionary note on accessing @options above */
3991 drvname
= qdict_get_try_str(options
, "driver");
3993 drv
= bdrv_find_format(drvname
);
3995 error_setg(errp
, "Unknown driver: '%s'", drvname
);
4000 assert(drvname
|| !(flags
& BDRV_O_PROTOCOL
));
4002 /* See cautionary note on accessing @options above */
4003 backing
= qdict_get_try_str(options
, "backing");
4004 if (qobject_to(QNull
, qdict_get(options
, "backing")) != NULL
||
4005 (backing
&& *backing
== '\0'))
4008 warn_report("Use of \"backing\": \"\" is deprecated; "
4009 "use \"backing\": null instead");
4011 flags
|= BDRV_O_NO_BACKING
;
4012 qdict_del(bs
->explicit_options
, "backing");
4013 qdict_del(bs
->options
, "backing");
4014 qdict_del(options
, "backing");
4017 /* Open image file without format layer. This BlockBackend is only used for
4018 * probing, the block drivers will do their own bdrv_open_child() for the
4019 * same BDS, which is why we put the node name back into options. */
4020 if ((flags
& BDRV_O_PROTOCOL
) == 0) {
4021 BlockDriverState
*file_bs
;
4023 file_bs
= bdrv_open_child_bs(filename
, options
, "file", bs
,
4024 &child_of_bds
, BDRV_CHILD_IMAGE
,
4029 if (file_bs
!= NULL
) {
4030 /* Not requesting BLK_PERM_CONSISTENT_READ because we're only
4031 * looking at the header to guess the image format. This works even
4032 * in cases where a guest would not see a consistent state. */
4033 ctx
= bdrv_get_aio_context(file_bs
);
4034 aio_context_acquire(ctx
);
4035 file
= blk_new(ctx
, 0, BLK_PERM_ALL
);
4036 blk_insert_bs(file
, file_bs
, &local_err
);
4037 bdrv_unref(file_bs
);
4038 aio_context_release(ctx
);
4044 qdict_put_str(options
, "file", bdrv_get_node_name(file_bs
));
4048 /* Image format probing */
4051 ret
= find_image_format(file
, filename
, &drv
, &local_err
);
4056 * This option update would logically belong in bdrv_fill_options(),
4057 * but we first need to open bs->file for the probing to work, while
4058 * opening bs->file already requires the (mostly) final set of options
4059 * so that cache mode etc. can be inherited.
4061 * Adding the driver later is somewhat ugly, but it's not an option
4062 * that would ever be inherited, so it's correct. We just need to make
4063 * sure to update both bs->options (which has the full effective
4064 * options for bs) and options (which has file.* already removed).
4066 qdict_put_str(bs
->options
, "driver", drv
->format_name
);
4067 qdict_put_str(options
, "driver", drv
->format_name
);
4069 error_setg(errp
, "Must specify either driver or file");
4073 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
4074 assert(!!(flags
& BDRV_O_PROTOCOL
) == !!drv
->bdrv_file_open
);
4075 /* file must be NULL if a protocol BDS is about to be created
4076 * (the inverse results in an error message from bdrv_open_common()) */
4077 assert(!(flags
& BDRV_O_PROTOCOL
) || !file
);
4079 /* Open the image */
4080 ret
= bdrv_open_common(bs
, file
, options
, &local_err
);
4085 /* The AioContext could have changed during bdrv_open_common() */
4086 ctx
= bdrv_get_aio_context(bs
);
4089 aio_context_acquire(ctx
);
4091 aio_context_release(ctx
);
4095 /* If there is a backing file, use it */
4096 if ((flags
& BDRV_O_NO_BACKING
) == 0) {
4097 ret
= bdrv_open_backing_file(bs
, options
, "backing", &local_err
);
4099 goto close_and_fail
;
4103 /* Remove all children options and references
4104 * from bs->options and bs->explicit_options */
4105 QLIST_FOREACH(child
, &bs
->children
, next
) {
4106 char *child_key_dot
;
4107 child_key_dot
= g_strdup_printf("%s.", child
->name
);
4108 qdict_extract_subqdict(bs
->explicit_options
, NULL
, child_key_dot
);
4109 qdict_extract_subqdict(bs
->options
, NULL
, child_key_dot
);
4110 qdict_del(bs
->explicit_options
, child
->name
);
4111 qdict_del(bs
->options
, child
->name
);
4112 g_free(child_key_dot
);
4115 /* Check if any unknown options were used */
4116 if (qdict_size(options
) != 0) {
4117 const QDictEntry
*entry
= qdict_first(options
);
4118 if (flags
& BDRV_O_PROTOCOL
) {
4119 error_setg(errp
, "Block protocol '%s' doesn't support the option "
4120 "'%s'", drv
->format_name
, entry
->key
);
4123 "Block format '%s' does not support the option '%s'",
4124 drv
->format_name
, entry
->key
);
4127 goto close_and_fail
;
4130 bdrv_parent_cb_change_media(bs
, true);
4132 qobject_unref(options
);
4135 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
4136 * temporary snapshot afterwards. */
4137 if (snapshot_flags
) {
4138 BlockDriverState
*snapshot_bs
;
4139 snapshot_bs
= bdrv_append_temp_snapshot(bs
, snapshot_flags
,
4140 snapshot_options
, &local_err
);
4141 snapshot_options
= NULL
;
4143 goto close_and_fail
;
4145 /* We are not going to return bs but the overlay on top of it
4146 * (snapshot_bs); thus, we have to drop the strong reference to bs
4147 * (which we obtained by calling bdrv_new()). bs will not be deleted,
4148 * though, because the overlay still has a reference to it. */
4149 aio_context_acquire(ctx
);
4151 aio_context_release(ctx
);
4158 aio_context_acquire(ctx
);
4160 qobject_unref(snapshot_options
);
4161 qobject_unref(bs
->explicit_options
);
4162 qobject_unref(bs
->options
);
4163 qobject_unref(options
);
4165 bs
->explicit_options
= NULL
;
4167 aio_context_release(ctx
);
4168 error_propagate(errp
, local_err
);
4172 aio_context_acquire(ctx
);
4174 aio_context_release(ctx
);
4175 qobject_unref(snapshot_options
);
4176 qobject_unref(options
);
4177 error_propagate(errp
, local_err
);
4181 /* The caller must always hold the main AioContext lock. */
4182 BlockDriverState
*bdrv_open(const char *filename
, const char *reference
,
4183 QDict
*options
, int flags
, Error
**errp
)
4185 GLOBAL_STATE_CODE();
4187 return bdrv_open_inherit(filename
, reference
, options
, flags
, NULL
,
4191 /* Return true if the NULL-terminated @list contains @str */
4192 static bool is_str_in_list(const char *str
, const char *const *list
)
4196 for (i
= 0; list
[i
] != NULL
; i
++) {
4197 if (!strcmp(str
, list
[i
])) {
4206 * Check that every option set in @bs->options is also set in
4209 * Options listed in the common_options list and in
4210 * @bs->drv->mutable_opts are skipped.
4212 * Return 0 on success, otherwise return -EINVAL and set @errp.
4214 static int bdrv_reset_options_allowed(BlockDriverState
*bs
,
4215 const QDict
*new_opts
, Error
**errp
)
4217 const QDictEntry
*e
;
4218 /* These options are common to all block drivers and are handled
4219 * in bdrv_reopen_prepare() so they can be left out of @new_opts */
4220 const char *const common_options
[] = {
4221 "node-name", "discard", "cache.direct", "cache.no-flush",
4222 "read-only", "auto-read-only", "detect-zeroes", NULL
4225 for (e
= qdict_first(bs
->options
); e
; e
= qdict_next(bs
->options
, e
)) {
4226 if (!qdict_haskey(new_opts
, e
->key
) &&
4227 !is_str_in_list(e
->key
, common_options
) &&
4228 !is_str_in_list(e
->key
, bs
->drv
->mutable_opts
)) {
4229 error_setg(errp
, "Option '%s' cannot be reset "
4230 "to its default value", e
->key
);
4239 * Returns true if @child can be reached recursively from @bs
4241 static bool bdrv_recurse_has_child(BlockDriverState
*bs
,
4242 BlockDriverState
*child
)
4250 QLIST_FOREACH(c
, &bs
->children
, next
) {
4251 if (bdrv_recurse_has_child(c
->bs
, child
)) {
4260 * Adds a BlockDriverState to a simple queue for an atomic, transactional
4261 * reopen of multiple devices.
4263 * bs_queue can either be an existing BlockReopenQueue that has had QTAILQ_INIT
4264 * already performed, or alternatively may be NULL a new BlockReopenQueue will
4265 * be created and initialized. This newly created BlockReopenQueue should be
4266 * passed back in for subsequent calls that are intended to be of the same
4269 * bs is the BlockDriverState to add to the reopen queue.
4271 * options contains the changed options for the associated bs
4272 * (the BlockReopenQueue takes ownership)
4274 * flags contains the open flags for the associated bs
4276 * returns a pointer to bs_queue, which is either the newly allocated
4277 * bs_queue, or the existing bs_queue being used.
4279 * bs is drained here and undrained by bdrv_reopen_queue_free().
4281 * To be called with bs->aio_context locked.
4283 static BlockReopenQueue
*bdrv_reopen_queue_child(BlockReopenQueue
*bs_queue
,
4284 BlockDriverState
*bs
,
4286 const BdrvChildClass
*klass
,
4288 bool parent_is_format
,
4289 QDict
*parent_options
,
4295 BlockReopenQueueEntry
*bs_entry
;
4297 QDict
*old_options
, *explicit_options
, *options_copy
;
4301 GLOBAL_STATE_CODE();
4303 bdrv_drained_begin(bs
);
4305 if (bs_queue
== NULL
) {
4306 bs_queue
= g_new0(BlockReopenQueue
, 1);
4307 QTAILQ_INIT(bs_queue
);
4311 options
= qdict_new();
4314 /* Check if this BlockDriverState is already in the queue */
4315 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4316 if (bs
== bs_entry
->state
.bs
) {
4322 * Precedence of options:
4323 * 1. Explicitly passed in options (highest)
4324 * 2. Retained from explicitly set options of bs
4325 * 3. Inherited from parent node
4326 * 4. Retained from effective options of bs
4329 /* Old explicitly set values (don't overwrite by inherited value) */
4330 if (bs_entry
|| keep_old_opts
) {
4331 old_options
= qdict_clone_shallow(bs_entry
?
4332 bs_entry
->state
.explicit_options
:
4333 bs
->explicit_options
);
4334 bdrv_join_options(bs
, options
, old_options
);
4335 qobject_unref(old_options
);
4338 explicit_options
= qdict_clone_shallow(options
);
4340 /* Inherit from parent node */
4341 if (parent_options
) {
4343 klass
->inherit_options(role
, parent_is_format
, &flags
, options
,
4344 parent_flags
, parent_options
);
4346 flags
= bdrv_get_flags(bs
);
4349 if (keep_old_opts
) {
4350 /* Old values are used for options that aren't set yet */
4351 old_options
= qdict_clone_shallow(bs
->options
);
4352 bdrv_join_options(bs
, options
, old_options
);
4353 qobject_unref(old_options
);
4356 /* We have the final set of options so let's update the flags */
4357 options_copy
= qdict_clone_shallow(options
);
4358 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
4359 qemu_opts_absorb_qdict(opts
, options_copy
, NULL
);
4360 update_flags_from_options(&flags
, opts
);
4361 qemu_opts_del(opts
);
4362 qobject_unref(options_copy
);
4364 /* bdrv_open_inherit() sets and clears some additional flags internally */
4365 flags
&= ~BDRV_O_PROTOCOL
;
4366 if (flags
& BDRV_O_RDWR
) {
4367 flags
|= BDRV_O_ALLOW_RDWR
;
4371 bs_entry
= g_new0(BlockReopenQueueEntry
, 1);
4372 QTAILQ_INSERT_TAIL(bs_queue
, bs_entry
, entry
);
4374 qobject_unref(bs_entry
->state
.options
);
4375 qobject_unref(bs_entry
->state
.explicit_options
);
4378 bs_entry
->state
.bs
= bs
;
4379 bs_entry
->state
.options
= options
;
4380 bs_entry
->state
.explicit_options
= explicit_options
;
4381 bs_entry
->state
.flags
= flags
;
4384 * If keep_old_opts is false then it means that unspecified
4385 * options must be reset to their original value. We don't allow
4386 * resetting 'backing' but we need to know if the option is
4387 * missing in order to decide if we have to return an error.
4389 if (!keep_old_opts
) {
4390 bs_entry
->state
.backing_missing
=
4391 !qdict_haskey(options
, "backing") &&
4392 !qdict_haskey(options
, "backing.driver");
4395 QLIST_FOREACH(child
, &bs
->children
, next
) {
4396 QDict
*new_child_options
= NULL
;
4397 bool child_keep_old
= keep_old_opts
;
4399 /* reopen can only change the options of block devices that were
4400 * implicitly created and inherited options. For other (referenced)
4401 * block devices, a syntax like "backing.foo" results in an error. */
4402 if (child
->bs
->inherits_from
!= bs
) {
4406 /* Check if the options contain a child reference */
4407 if (qdict_haskey(options
, child
->name
)) {
4408 const char *childref
= qdict_get_try_str(options
, child
->name
);
4410 * The current child must not be reopened if the child
4411 * reference is null or points to a different node.
4413 if (g_strcmp0(childref
, child
->bs
->node_name
)) {
4417 * If the child reference points to the current child then
4418 * reopen it with its existing set of options (note that
4419 * it can still inherit new options from the parent).
4421 child_keep_old
= true;
4423 /* Extract child options ("child-name.*") */
4424 char *child_key_dot
= g_strdup_printf("%s.", child
->name
);
4425 qdict_extract_subqdict(explicit_options
, NULL
, child_key_dot
);
4426 qdict_extract_subqdict(options
, &new_child_options
, child_key_dot
);
4427 g_free(child_key_dot
);
4430 bdrv_reopen_queue_child(bs_queue
, child
->bs
, new_child_options
,
4431 child
->klass
, child
->role
, bs
->drv
->is_format
,
4432 options
, flags
, child_keep_old
);
4438 /* To be called with bs->aio_context locked */
4439 BlockReopenQueue
*bdrv_reopen_queue(BlockReopenQueue
*bs_queue
,
4440 BlockDriverState
*bs
,
4441 QDict
*options
, bool keep_old_opts
)
4443 GLOBAL_STATE_CODE();
4445 return bdrv_reopen_queue_child(bs_queue
, bs
, options
, NULL
, 0, false,
4446 NULL
, 0, keep_old_opts
);
4449 void bdrv_reopen_queue_free(BlockReopenQueue
*bs_queue
)
4451 GLOBAL_STATE_CODE();
4453 BlockReopenQueueEntry
*bs_entry
, *next
;
4454 QTAILQ_FOREACH_SAFE(bs_entry
, bs_queue
, entry
, next
) {
4455 AioContext
*ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4457 aio_context_acquire(ctx
);
4458 bdrv_drained_end(bs_entry
->state
.bs
);
4459 aio_context_release(ctx
);
4461 qobject_unref(bs_entry
->state
.explicit_options
);
4462 qobject_unref(bs_entry
->state
.options
);
4470 * Reopen multiple BlockDriverStates atomically & transactionally.
4472 * The queue passed in (bs_queue) must have been built up previous
4473 * via bdrv_reopen_queue().
4475 * Reopens all BDS specified in the queue, with the appropriate
4476 * flags. All devices are prepared for reopen, and failure of any
4477 * device will cause all device changes to be abandoned, and intermediate
4480 * If all devices prepare successfully, then the changes are committed
4483 * All affected nodes must be drained between bdrv_reopen_queue() and
4484 * bdrv_reopen_multiple().
4486 * To be called from the main thread, with all other AioContexts unlocked.
4488 int bdrv_reopen_multiple(BlockReopenQueue
*bs_queue
, Error
**errp
)
4491 BlockReopenQueueEntry
*bs_entry
, *next
;
4493 Transaction
*tran
= tran_new();
4494 g_autoptr(GSList
) refresh_list
= NULL
;
4496 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
4497 assert(bs_queue
!= NULL
);
4498 GLOBAL_STATE_CODE();
4500 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4501 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4502 aio_context_acquire(ctx
);
4503 ret
= bdrv_flush(bs_entry
->state
.bs
);
4504 aio_context_release(ctx
);
4506 error_setg_errno(errp
, -ret
, "Error flushing drive");
4511 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4512 assert(bs_entry
->state
.bs
->quiesce_counter
> 0);
4513 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4514 aio_context_acquire(ctx
);
4515 ret
= bdrv_reopen_prepare(&bs_entry
->state
, bs_queue
, tran
, errp
);
4516 aio_context_release(ctx
);
4520 bs_entry
->prepared
= true;
4523 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4524 BDRVReopenState
*state
= &bs_entry
->state
;
4526 refresh_list
= g_slist_prepend(refresh_list
, state
->bs
);
4527 if (state
->old_backing_bs
) {
4528 refresh_list
= g_slist_prepend(refresh_list
, state
->old_backing_bs
);
4530 if (state
->old_file_bs
) {
4531 refresh_list
= g_slist_prepend(refresh_list
, state
->old_file_bs
);
4536 * Note that file-posix driver rely on permission update done during reopen
4537 * (even if no permission changed), because it wants "new" permissions for
4538 * reconfiguring the fd and that's why it does it in raw_check_perm(), not
4539 * in raw_reopen_prepare() which is called with "old" permissions.
4541 ret
= bdrv_list_refresh_perms(refresh_list
, bs_queue
, tran
, errp
);
4547 * If we reach this point, we have success and just need to apply the
4550 * Reverse order is used to comfort qcow2 driver: on commit it need to write
4551 * IN_USE flag to the image, to mark bitmaps in the image as invalid. But
4552 * children are usually goes after parents in reopen-queue, so go from last
4555 QTAILQ_FOREACH_REVERSE(bs_entry
, bs_queue
, entry
) {
4556 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4557 aio_context_acquire(ctx
);
4558 bdrv_reopen_commit(&bs_entry
->state
);
4559 aio_context_release(ctx
);
4564 QTAILQ_FOREACH_REVERSE(bs_entry
, bs_queue
, entry
) {
4565 BlockDriverState
*bs
= bs_entry
->state
.bs
;
4567 if (bs
->drv
->bdrv_reopen_commit_post
) {
4568 ctx
= bdrv_get_aio_context(bs
);
4569 aio_context_acquire(ctx
);
4570 bs
->drv
->bdrv_reopen_commit_post(&bs_entry
->state
);
4571 aio_context_release(ctx
);
4580 QTAILQ_FOREACH_SAFE(bs_entry
, bs_queue
, entry
, next
) {
4581 if (bs_entry
->prepared
) {
4582 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4583 aio_context_acquire(ctx
);
4584 bdrv_reopen_abort(&bs_entry
->state
);
4585 aio_context_release(ctx
);
4590 bdrv_reopen_queue_free(bs_queue
);
4595 int bdrv_reopen(BlockDriverState
*bs
, QDict
*opts
, bool keep_old_opts
,
4598 AioContext
*ctx
= bdrv_get_aio_context(bs
);
4599 BlockReopenQueue
*queue
;
4602 GLOBAL_STATE_CODE();
4604 queue
= bdrv_reopen_queue(NULL
, bs
, opts
, keep_old_opts
);
4606 if (ctx
!= qemu_get_aio_context()) {
4607 aio_context_release(ctx
);
4609 ret
= bdrv_reopen_multiple(queue
, errp
);
4611 if (ctx
!= qemu_get_aio_context()) {
4612 aio_context_acquire(ctx
);
4618 int bdrv_reopen_set_read_only(BlockDriverState
*bs
, bool read_only
,
4621 QDict
*opts
= qdict_new();
4623 GLOBAL_STATE_CODE();
4625 qdict_put_bool(opts
, BDRV_OPT_READ_ONLY
, read_only
);
4627 return bdrv_reopen(bs
, opts
, true, errp
);
4631 * Take a BDRVReopenState and check if the value of 'backing' in the
4632 * reopen_state->options QDict is valid or not.
4634 * If 'backing' is missing from the QDict then return 0.
4636 * If 'backing' contains the node name of the backing file of
4637 * reopen_state->bs then return 0.
4639 * If 'backing' contains a different node name (or is null) then check
4640 * whether the current backing file can be replaced with the new one.
4641 * If that's the case then reopen_state->replace_backing_bs is set to
4642 * true and reopen_state->new_backing_bs contains a pointer to the new
4643 * backing BlockDriverState (or NULL).
4645 * Return 0 on success, otherwise return < 0 and set @errp.
4647 * The caller must hold the AioContext lock of @reopen_state->bs.
4648 * @reopen_state->bs can move to a different AioContext in this function.
4649 * Callers must make sure that their AioContext locking is still correct after
4652 static int bdrv_reopen_parse_file_or_backing(BDRVReopenState
*reopen_state
,
4653 bool is_backing
, Transaction
*tran
,
4656 BlockDriverState
*bs
= reopen_state
->bs
;
4657 BlockDriverState
*new_child_bs
;
4658 BlockDriverState
*old_child_bs
= is_backing
? child_bs(bs
->backing
) :
4660 const char *child_name
= is_backing
? "backing" : "file";
4663 AioContext
*ctx
, *old_ctx
;
4666 GLOBAL_STATE_CODE();
4668 value
= qdict_get(reopen_state
->options
, child_name
);
4669 if (value
== NULL
) {
4673 switch (qobject_type(value
)) {
4675 assert(is_backing
); /* The 'file' option does not allow a null value */
4676 new_child_bs
= NULL
;
4679 str
= qstring_get_str(qobject_to(QString
, value
));
4680 new_child_bs
= bdrv_lookup_bs(NULL
, str
, errp
);
4681 if (new_child_bs
== NULL
) {
4683 } else if (bdrv_recurse_has_child(new_child_bs
, bs
)) {
4684 error_setg(errp
, "Making '%s' a %s child of '%s' would create a "
4685 "cycle", str
, child_name
, bs
->node_name
);
4691 * The options QDict has been flattened, so 'backing' and 'file'
4692 * do not allow any other data type here.
4694 g_assert_not_reached();
4697 if (old_child_bs
== new_child_bs
) {
4702 if (bdrv_skip_implicit_filters(old_child_bs
) == new_child_bs
) {
4706 if (old_child_bs
->implicit
) {
4707 error_setg(errp
, "Cannot replace implicit %s child of %s",
4708 child_name
, bs
->node_name
);
4713 if (bs
->drv
->is_filter
&& !old_child_bs
) {
4715 * Filters always have a file or a backing child, so we are trying to
4716 * change wrong child
4718 error_setg(errp
, "'%s' is a %s filter node that does not support a "
4719 "%s child", bs
->node_name
, bs
->drv
->format_name
, child_name
);
4724 reopen_state
->old_backing_bs
= old_child_bs
;
4726 reopen_state
->old_file_bs
= old_child_bs
;
4729 old_ctx
= bdrv_get_aio_context(bs
);
4730 ctx
= bdrv_get_aio_context(new_child_bs
);
4731 if (old_ctx
!= ctx
) {
4732 aio_context_release(old_ctx
);
4733 aio_context_acquire(ctx
);
4736 ret
= bdrv_set_file_or_backing_noperm(bs
, new_child_bs
, is_backing
,
4739 if (old_ctx
!= ctx
) {
4740 aio_context_release(ctx
);
4741 aio_context_acquire(old_ctx
);
4748 * Prepares a BlockDriverState for reopen. All changes are staged in the
4749 * 'opaque' field of the BDRVReopenState, which is used and allocated by
4750 * the block driver layer .bdrv_reopen_prepare()
4752 * bs is the BlockDriverState to reopen
4753 * flags are the new open flags
4754 * queue is the reopen queue
4756 * Returns 0 on success, non-zero on error. On error errp will be set
4759 * On failure, bdrv_reopen_abort() will be called to clean up any data.
4760 * It is the responsibility of the caller to then call the abort() or
4761 * commit() for any other BDS that have been left in a prepare() state
4763 * The caller must hold the AioContext lock of @reopen_state->bs.
4765 static int bdrv_reopen_prepare(BDRVReopenState
*reopen_state
,
4766 BlockReopenQueue
*queue
,
4767 Transaction
*change_child_tran
, Error
**errp
)
4771 Error
*local_err
= NULL
;
4774 QDict
*orig_reopen_opts
;
4775 char *discard
= NULL
;
4777 bool drv_prepared
= false;
4779 assert(reopen_state
!= NULL
);
4780 assert(reopen_state
->bs
->drv
!= NULL
);
4781 GLOBAL_STATE_CODE();
4782 drv
= reopen_state
->bs
->drv
;
4784 /* This function and each driver's bdrv_reopen_prepare() remove
4785 * entries from reopen_state->options as they are processed, so
4786 * we need to make a copy of the original QDict. */
4787 orig_reopen_opts
= qdict_clone_shallow(reopen_state
->options
);
4789 /* Process generic block layer options */
4790 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
4791 if (!qemu_opts_absorb_qdict(opts
, reopen_state
->options
, errp
)) {
4796 /* This was already called in bdrv_reopen_queue_child() so the flags
4797 * are up-to-date. This time we simply want to remove the options from
4798 * QemuOpts in order to indicate that they have been processed. */
4799 old_flags
= reopen_state
->flags
;
4800 update_flags_from_options(&reopen_state
->flags
, opts
);
4801 assert(old_flags
== reopen_state
->flags
);
4803 discard
= qemu_opt_get_del(opts
, BDRV_OPT_DISCARD
);
4804 if (discard
!= NULL
) {
4805 if (bdrv_parse_discard_flags(discard
, &reopen_state
->flags
) != 0) {
4806 error_setg(errp
, "Invalid discard option");
4812 reopen_state
->detect_zeroes
=
4813 bdrv_parse_detect_zeroes(opts
, reopen_state
->flags
, &local_err
);
4815 error_propagate(errp
, local_err
);
4820 /* All other options (including node-name and driver) must be unchanged.
4821 * Put them back into the QDict, so that they are checked at the end
4822 * of this function. */
4823 qemu_opts_to_qdict(opts
, reopen_state
->options
);
4825 /* If we are to stay read-only, do not allow permission change
4826 * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is
4827 * not set, or if the BDS still has copy_on_read enabled */
4828 read_only
= !(reopen_state
->flags
& BDRV_O_RDWR
);
4829 ret
= bdrv_can_set_read_only(reopen_state
->bs
, read_only
, true, &local_err
);
4831 error_propagate(errp
, local_err
);
4835 if (drv
->bdrv_reopen_prepare
) {
4837 * If a driver-specific option is missing, it means that we
4838 * should reset it to its default value.
4839 * But not all options allow that, so we need to check it first.
4841 ret
= bdrv_reset_options_allowed(reopen_state
->bs
,
4842 reopen_state
->options
, errp
);
4847 ret
= drv
->bdrv_reopen_prepare(reopen_state
, queue
, &local_err
);
4849 if (local_err
!= NULL
) {
4850 error_propagate(errp
, local_err
);
4852 bdrv_refresh_filename(reopen_state
->bs
);
4853 error_setg(errp
, "failed while preparing to reopen image '%s'",
4854 reopen_state
->bs
->filename
);
4859 /* It is currently mandatory to have a bdrv_reopen_prepare()
4860 * handler for each supported drv. */
4861 error_setg(errp
, "Block format '%s' used by node '%s' "
4862 "does not support reopening files", drv
->format_name
,
4863 bdrv_get_device_or_node_name(reopen_state
->bs
));
4868 drv_prepared
= true;
4871 * We must provide the 'backing' option if the BDS has a backing
4872 * file or if the image file has a backing file name as part of
4873 * its metadata. Otherwise the 'backing' option can be omitted.
4875 if (drv
->supports_backing
&& reopen_state
->backing_missing
&&
4876 (reopen_state
->bs
->backing
|| reopen_state
->bs
->backing_file
[0])) {
4877 error_setg(errp
, "backing is missing for '%s'",
4878 reopen_state
->bs
->node_name
);
4884 * Allow changing the 'backing' option. The new value can be
4885 * either a reference to an existing node (using its node name)
4886 * or NULL to simply detach the current backing file.
4888 ret
= bdrv_reopen_parse_file_or_backing(reopen_state
, true,
4889 change_child_tran
, errp
);
4893 qdict_del(reopen_state
->options
, "backing");
4895 /* Allow changing the 'file' option. In this case NULL is not allowed */
4896 ret
= bdrv_reopen_parse_file_or_backing(reopen_state
, false,
4897 change_child_tran
, errp
);
4901 qdict_del(reopen_state
->options
, "file");
4903 /* Options that are not handled are only okay if they are unchanged
4904 * compared to the old state. It is expected that some options are only
4905 * used for the initial open, but not reopen (e.g. filename) */
4906 if (qdict_size(reopen_state
->options
)) {
4907 const QDictEntry
*entry
= qdict_first(reopen_state
->options
);
4910 QObject
*new = entry
->value
;
4911 QObject
*old
= qdict_get(reopen_state
->bs
->options
, entry
->key
);
4913 /* Allow child references (child_name=node_name) as long as they
4914 * point to the current child (i.e. everything stays the same). */
4915 if (qobject_type(new) == QTYPE_QSTRING
) {
4917 QLIST_FOREACH(child
, &reopen_state
->bs
->children
, next
) {
4918 if (!strcmp(child
->name
, entry
->key
)) {
4924 if (!strcmp(child
->bs
->node_name
,
4925 qstring_get_str(qobject_to(QString
, new)))) {
4926 continue; /* Found child with this name, skip option */
4932 * TODO: When using -drive to specify blockdev options, all values
4933 * will be strings; however, when using -blockdev, blockdev-add or
4934 * filenames using the json:{} pseudo-protocol, they will be
4936 * In contrast, reopening options are (currently) always strings
4937 * (because you can only specify them through qemu-io; all other
4938 * callers do not specify any options).
4939 * Therefore, when using anything other than -drive to create a BDS,
4940 * this cannot detect non-string options as unchanged, because
4941 * qobject_is_equal() always returns false for objects of different
4942 * type. In the future, this should be remedied by correctly typing
4943 * all options. For now, this is not too big of an issue because
4944 * the user can simply omit options which cannot be changed anyway,
4945 * so they will stay unchanged.
4947 if (!qobject_is_equal(new, old
)) {
4948 error_setg(errp
, "Cannot change the option '%s'", entry
->key
);
4952 } while ((entry
= qdict_next(reopen_state
->options
, entry
)));
4957 /* Restore the original reopen_state->options QDict */
4958 qobject_unref(reopen_state
->options
);
4959 reopen_state
->options
= qobject_ref(orig_reopen_opts
);
4962 if (ret
< 0 && drv_prepared
) {
4963 /* drv->bdrv_reopen_prepare() has succeeded, so we need to
4964 * call drv->bdrv_reopen_abort() before signaling an error
4965 * (bdrv_reopen_multiple() will not call bdrv_reopen_abort()
4966 * when the respective bdrv_reopen_prepare() has failed) */
4967 if (drv
->bdrv_reopen_abort
) {
4968 drv
->bdrv_reopen_abort(reopen_state
);
4971 qemu_opts_del(opts
);
4972 qobject_unref(orig_reopen_opts
);
4978 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
4979 * makes them final by swapping the staging BlockDriverState contents into
4980 * the active BlockDriverState contents.
4982 static void bdrv_reopen_commit(BDRVReopenState
*reopen_state
)
4985 BlockDriverState
*bs
;
4988 assert(reopen_state
!= NULL
);
4989 bs
= reopen_state
->bs
;
4991 assert(drv
!= NULL
);
4992 GLOBAL_STATE_CODE();
4994 /* If there are any driver level actions to take */
4995 if (drv
->bdrv_reopen_commit
) {
4996 drv
->bdrv_reopen_commit(reopen_state
);
4999 /* set BDS specific flags now */
5000 qobject_unref(bs
->explicit_options
);
5001 qobject_unref(bs
->options
);
5002 qobject_ref(reopen_state
->explicit_options
);
5003 qobject_ref(reopen_state
->options
);
5005 bs
->explicit_options
= reopen_state
->explicit_options
;
5006 bs
->options
= reopen_state
->options
;
5007 bs
->open_flags
= reopen_state
->flags
;
5008 bs
->detect_zeroes
= reopen_state
->detect_zeroes
;
5010 /* Remove child references from bs->options and bs->explicit_options.
5011 * Child options were already removed in bdrv_reopen_queue_child() */
5012 QLIST_FOREACH(child
, &bs
->children
, next
) {
5013 qdict_del(bs
->explicit_options
, child
->name
);
5014 qdict_del(bs
->options
, child
->name
);
5016 /* backing is probably removed, so it's not handled by previous loop */
5017 qdict_del(bs
->explicit_options
, "backing");
5018 qdict_del(bs
->options
, "backing");
5020 bdrv_graph_rdlock_main_loop();
5021 bdrv_refresh_limits(bs
, NULL
, NULL
);
5022 bdrv_graph_rdunlock_main_loop();
5023 bdrv_refresh_total_sectors(bs
, bs
->total_sectors
);
5027 * Abort the reopen, and delete and free the staged changes in
5030 static void bdrv_reopen_abort(BDRVReopenState
*reopen_state
)
5034 assert(reopen_state
!= NULL
);
5035 drv
= reopen_state
->bs
->drv
;
5036 assert(drv
!= NULL
);
5037 GLOBAL_STATE_CODE();
5039 if (drv
->bdrv_reopen_abort
) {
5040 drv
->bdrv_reopen_abort(reopen_state
);
5045 static void bdrv_close(BlockDriverState
*bs
)
5047 BdrvAioNotifier
*ban
, *ban_next
;
5048 BdrvChild
*child
, *next
;
5050 GLOBAL_STATE_CODE();
5051 assert(!bs
->refcnt
);
5053 bdrv_drained_begin(bs
); /* complete I/O */
5055 bdrv_drain(bs
); /* in case flush left pending I/O */
5058 if (bs
->drv
->bdrv_close
) {
5059 /* Must unfreeze all children, so bdrv_unref_child() works */
5060 bs
->drv
->bdrv_close(bs
);
5065 QLIST_FOREACH_SAFE(child
, &bs
->children
, next
, next
) {
5066 bdrv_unref_child(bs
, child
);
5069 assert(!bs
->backing
);
5073 qatomic_set(&bs
->copy_on_read
, 0);
5074 bs
->backing_file
[0] = '\0';
5075 bs
->backing_format
[0] = '\0';
5076 bs
->total_sectors
= 0;
5077 bs
->encrypted
= false;
5079 qobject_unref(bs
->options
);
5080 qobject_unref(bs
->explicit_options
);
5082 bs
->explicit_options
= NULL
;
5083 qobject_unref(bs
->full_open_options
);
5084 bs
->full_open_options
= NULL
;
5085 g_free(bs
->block_status_cache
);
5086 bs
->block_status_cache
= NULL
;
5088 bdrv_release_named_dirty_bitmaps(bs
);
5089 assert(QLIST_EMPTY(&bs
->dirty_bitmaps
));
5091 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_next
) {
5094 QLIST_INIT(&bs
->aio_notifiers
);
5095 bdrv_drained_end(bs
);
5098 * If we're still inside some bdrv_drain_all_begin()/end() sections, end
5099 * them now since this BDS won't exist anymore when bdrv_drain_all_end()
5102 if (bs
->quiesce_counter
) {
5103 bdrv_drain_all_end_quiesce(bs
);
5107 void bdrv_close_all(void)
5109 GLOBAL_STATE_CODE();
5110 assert(job_next(NULL
) == NULL
);
5112 /* Drop references from requests still in flight, such as canceled block
5113 * jobs whose AIO context has not been polled yet */
5116 blk_remove_all_bs();
5117 blockdev_close_all_bdrv_states();
5119 assert(QTAILQ_EMPTY(&all_bdrv_states
));
5122 static bool should_update_child(BdrvChild
*c
, BlockDriverState
*to
)
5128 if (c
->klass
->stay_at_node
) {
5132 /* If the child @c belongs to the BDS @to, replacing the current
5133 * c->bs by @to would mean to create a loop.
5135 * Such a case occurs when appending a BDS to a backing chain.
5136 * For instance, imagine the following chain:
5138 * guest device -> node A -> further backing chain...
5140 * Now we create a new BDS B which we want to put on top of this
5141 * chain, so we first attach A as its backing node:
5146 * guest device -> node A -> further backing chain...
5148 * Finally we want to replace A by B. When doing that, we want to
5149 * replace all pointers to A by pointers to B -- except for the
5150 * pointer from B because (1) that would create a loop, and (2)
5151 * that pointer should simply stay intact:
5153 * guest device -> node B
5156 * node A -> further backing chain...
5158 * In general, when replacing a node A (c->bs) by a node B (@to),
5159 * if A is a child of B, that means we cannot replace A by B there
5160 * because that would create a loop. Silently detaching A from B
5161 * is also not really an option. So overall just leaving A in
5162 * place there is the most sensible choice.
5164 * We would also create a loop in any cases where @c is only
5165 * indirectly referenced by @to. Prevent this by returning false
5166 * if @c is found (by breadth-first search) anywhere in the whole
5171 found
= g_hash_table_new(NULL
, NULL
);
5172 g_hash_table_add(found
, to
);
5173 queue
= g_queue_new();
5174 g_queue_push_tail(queue
, to
);
5176 while (!g_queue_is_empty(queue
)) {
5177 BlockDriverState
*v
= g_queue_pop_head(queue
);
5180 QLIST_FOREACH(c2
, &v
->children
, next
) {
5186 if (g_hash_table_contains(found
, c2
->bs
)) {
5190 g_queue_push_tail(queue
, c2
->bs
);
5191 g_hash_table_add(found
, c2
->bs
);
5195 g_queue_free(queue
);
5196 g_hash_table_destroy(found
);
5201 static void bdrv_remove_child_commit(void *opaque
)
5203 GLOBAL_STATE_CODE();
5204 bdrv_child_free(opaque
);
5207 static TransactionActionDrv bdrv_remove_child_drv
= {
5208 .commit
= bdrv_remove_child_commit
,
5211 /* Function doesn't update permissions, caller is responsible for this. */
5212 static void bdrv_remove_child(BdrvChild
*child
, Transaction
*tran
)
5219 BlockDriverState
*bs
= child
->bs
;
5220 bdrv_drained_begin(bs
);
5221 bdrv_replace_child_tran(child
, NULL
, tran
);
5222 bdrv_drained_end(bs
);
5225 tran_add(tran
, &bdrv_remove_child_drv
, child
);
5228 static void undrain_on_clean_cb(void *opaque
)
5230 bdrv_drained_end(opaque
);
5233 static TransactionActionDrv undrain_on_clean
= {
5234 .clean
= undrain_on_clean_cb
,
5237 static int bdrv_replace_node_noperm(BlockDriverState
*from
,
5238 BlockDriverState
*to
,
5239 bool auto_skip
, Transaction
*tran
,
5242 BdrvChild
*c
, *next
;
5244 GLOBAL_STATE_CODE();
5246 bdrv_drained_begin(from
);
5247 bdrv_drained_begin(to
);
5248 tran_add(tran
, &undrain_on_clean
, from
);
5249 tran_add(tran
, &undrain_on_clean
, to
);
5251 QLIST_FOREACH_SAFE(c
, &from
->parents
, next_parent
, next
) {
5252 assert(c
->bs
== from
);
5253 if (!should_update_child(c
, to
)) {
5257 error_setg(errp
, "Should not change '%s' link to '%s'",
5258 c
->name
, from
->node_name
);
5262 error_setg(errp
, "Cannot change '%s' link to '%s'",
5263 c
->name
, from
->node_name
);
5266 bdrv_replace_child_tran(c
, to
, tran
);
5273 * With auto_skip=true bdrv_replace_node_common skips updating from parents
5274 * if it creates a parent-child relation loop or if parent is block-job.
5276 * With auto_skip=false the error is returned if from has a parent which should
5279 * With @detach_subchain=true @to must be in a backing chain of @from. In this
5280 * case backing link of the cow-parent of @to is removed.
5282 static int bdrv_replace_node_common(BlockDriverState
*from
,
5283 BlockDriverState
*to
,
5284 bool auto_skip
, bool detach_subchain
,
5287 Transaction
*tran
= tran_new();
5288 g_autoptr(GSList
) refresh_list
= NULL
;
5289 BlockDriverState
*to_cow_parent
= NULL
;
5292 GLOBAL_STATE_CODE();
5294 if (detach_subchain
) {
5295 assert(bdrv_chain_contains(from
, to
));
5297 for (to_cow_parent
= from
;
5298 bdrv_filter_or_cow_bs(to_cow_parent
) != to
;
5299 to_cow_parent
= bdrv_filter_or_cow_bs(to_cow_parent
))
5305 /* Make sure that @from doesn't go away until we have successfully attached
5306 * all of its parents to @to. */
5309 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
5310 assert(bdrv_get_aio_context(from
) == bdrv_get_aio_context(to
));
5311 bdrv_drained_begin(from
);
5314 * Do the replacement without permission update.
5315 * Replacement may influence the permissions, we should calculate new
5316 * permissions based on new graph. If we fail, we'll roll-back the
5319 ret
= bdrv_replace_node_noperm(from
, to
, auto_skip
, tran
, errp
);
5324 if (detach_subchain
) {
5325 bdrv_remove_child(bdrv_filter_or_cow_child(to_cow_parent
), tran
);
5328 refresh_list
= g_slist_prepend(refresh_list
, to
);
5329 refresh_list
= g_slist_prepend(refresh_list
, from
);
5331 ret
= bdrv_list_refresh_perms(refresh_list
, NULL
, tran
, errp
);
5339 tran_finalize(tran
, ret
);
5341 bdrv_drained_end(from
);
5347 int bdrv_replace_node(BlockDriverState
*from
, BlockDriverState
*to
,
5350 GLOBAL_STATE_CODE();
5352 return bdrv_replace_node_common(from
, to
, true, false, errp
);
5355 int bdrv_drop_filter(BlockDriverState
*bs
, Error
**errp
)
5357 GLOBAL_STATE_CODE();
5359 return bdrv_replace_node_common(bs
, bdrv_filter_or_cow_bs(bs
), true, true,
5364 * Add new bs contents at the top of an image chain while the chain is
5365 * live, while keeping required fields on the top layer.
5367 * This will modify the BlockDriverState fields, and swap contents
5368 * between bs_new and bs_top. Both bs_new and bs_top are modified.
5370 * bs_new must not be attached to a BlockBackend and must not have backing
5373 * This function does not create any image files.
5375 * The caller must hold the AioContext lock for @bs_top.
5377 int bdrv_append(BlockDriverState
*bs_new
, BlockDriverState
*bs_top
,
5382 Transaction
*tran
= tran_new();
5383 AioContext
*old_context
, *new_context
= NULL
;
5385 GLOBAL_STATE_CODE();
5387 assert(!bs_new
->backing
);
5389 old_context
= bdrv_get_aio_context(bs_top
);
5391 child
= bdrv_attach_child_noperm(bs_new
, bs_top
, "backing",
5392 &child_of_bds
, bdrv_backing_role(bs_new
),
5400 * bdrv_attach_child_noperm could change the AioContext of bs_top.
5401 * bdrv_replace_node_noperm calls bdrv_drained_begin, so let's temporarily
5402 * hold the new AioContext, since bdrv_drained_begin calls BDRV_POLL_WHILE
5403 * that assumes the new lock is taken.
5405 new_context
= bdrv_get_aio_context(bs_top
);
5407 if (old_context
!= new_context
) {
5408 aio_context_release(old_context
);
5409 aio_context_acquire(new_context
);
5412 ret
= bdrv_replace_node_noperm(bs_top
, bs_new
, true, tran
, errp
);
5417 ret
= bdrv_refresh_perms(bs_new
, tran
, errp
);
5419 tran_finalize(tran
, ret
);
5421 bdrv_graph_rdlock_main_loop();
5422 bdrv_refresh_limits(bs_top
, NULL
, NULL
);
5423 bdrv_graph_rdunlock_main_loop();
5425 if (new_context
&& old_context
!= new_context
) {
5426 aio_context_release(new_context
);
5427 aio_context_acquire(old_context
);
5433 /* Not for empty child */
5434 int bdrv_replace_child_bs(BdrvChild
*child
, BlockDriverState
*new_bs
,
5438 Transaction
*tran
= tran_new();
5439 g_autoptr(GSList
) refresh_list
= NULL
;
5440 BlockDriverState
*old_bs
= child
->bs
;
5442 GLOBAL_STATE_CODE();
5445 bdrv_drained_begin(old_bs
);
5446 bdrv_drained_begin(new_bs
);
5448 bdrv_replace_child_tran(child
, new_bs
, tran
);
5450 refresh_list
= g_slist_prepend(refresh_list
, old_bs
);
5451 refresh_list
= g_slist_prepend(refresh_list
, new_bs
);
5453 ret
= bdrv_list_refresh_perms(refresh_list
, NULL
, tran
, errp
);
5455 tran_finalize(tran
, ret
);
5457 bdrv_drained_end(old_bs
);
5458 bdrv_drained_end(new_bs
);
5464 static void bdrv_delete(BlockDriverState
*bs
)
5466 assert(bdrv_op_blocker_is_empty(bs
));
5467 assert(!bs
->refcnt
);
5468 GLOBAL_STATE_CODE();
5470 /* remove from list, if necessary */
5471 if (bs
->node_name
[0] != '\0') {
5472 QTAILQ_REMOVE(&graph_bdrv_states
, bs
, node_list
);
5474 QTAILQ_REMOVE(&all_bdrv_states
, bs
, bs_list
);
5483 * Replace @bs by newly created block node.
5485 * @options is a QDict of options to pass to the block drivers, or NULL for an
5486 * empty set of options. The reference to the QDict belongs to the block layer
5487 * after the call (even on failure), so if the caller intends to reuse the
5488 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
5490 * The caller holds the AioContext lock for @bs. It must make sure that @bs
5491 * stays in the same AioContext, i.e. @options must not refer to nodes in a
5492 * different AioContext.
5494 BlockDriverState
*bdrv_insert_node(BlockDriverState
*bs
, QDict
*options
,
5495 int flags
, Error
**errp
)
5499 AioContext
*ctx
= bdrv_get_aio_context(bs
);
5500 BlockDriverState
*new_node_bs
= NULL
;
5501 const char *drvname
, *node_name
;
5504 drvname
= qdict_get_try_str(options
, "driver");
5506 error_setg(errp
, "driver is not specified");
5510 drv
= bdrv_find_format(drvname
);
5512 error_setg(errp
, "Unknown driver: '%s'", drvname
);
5516 node_name
= qdict_get_try_str(options
, "node-name");
5518 GLOBAL_STATE_CODE();
5520 aio_context_release(ctx
);
5521 aio_context_acquire(qemu_get_aio_context());
5522 new_node_bs
= bdrv_new_open_driver_opts(drv
, node_name
, options
, flags
,
5524 aio_context_release(qemu_get_aio_context());
5525 aio_context_acquire(ctx
);
5526 assert(bdrv_get_aio_context(bs
) == ctx
);
5528 options
= NULL
; /* bdrv_new_open_driver() eats options */
5530 error_prepend(errp
, "Could not create node: ");
5534 bdrv_drained_begin(bs
);
5535 ret
= bdrv_replace_node(bs
, new_node_bs
, errp
);
5536 bdrv_drained_end(bs
);
5539 error_prepend(errp
, "Could not replace node: ");
5546 qobject_unref(options
);
5547 bdrv_unref(new_node_bs
);
5552 * Run consistency checks on an image
5554 * Returns 0 if the check could be completed (it doesn't mean that the image is
5555 * free of errors) or -errno when an internal error occurred. The results of the
5556 * check are stored in res.
5558 int coroutine_fn
bdrv_co_check(BlockDriverState
*bs
,
5559 BdrvCheckResult
*res
, BdrvCheckMode fix
)
5562 assert_bdrv_graph_readable();
5563 if (bs
->drv
== NULL
) {
5566 if (bs
->drv
->bdrv_co_check
== NULL
) {
5570 memset(res
, 0, sizeof(*res
));
5571 return bs
->drv
->bdrv_co_check(bs
, res
, fix
);
5577 * -EINVAL - backing format specified, but no file
5578 * -ENOSPC - can't update the backing file because no space is left in the
5580 * -ENOTSUP - format driver doesn't support changing the backing file
5582 int bdrv_change_backing_file(BlockDriverState
*bs
, const char *backing_file
,
5583 const char *backing_fmt
, bool require
)
5585 BlockDriver
*drv
= bs
->drv
;
5588 GLOBAL_STATE_CODE();
5594 /* Backing file format doesn't make sense without a backing file */
5595 if (backing_fmt
&& !backing_file
) {
5599 if (require
&& backing_file
&& !backing_fmt
) {
5603 if (drv
->bdrv_change_backing_file
!= NULL
) {
5604 ret
= drv
->bdrv_change_backing_file(bs
, backing_file
, backing_fmt
);
5610 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
), backing_file
?: "");
5611 pstrcpy(bs
->backing_format
, sizeof(bs
->backing_format
), backing_fmt
?: "");
5612 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
5613 backing_file
?: "");
5619 * Finds the first non-filter node above bs in the chain between
5620 * active and bs. The returned node is either an immediate parent of
5621 * bs, or there are only filter nodes between the two.
5623 * Returns NULL if bs is not found in active's image chain,
5624 * or if active == bs.
5626 * Returns the bottommost base image if bs == NULL.
5628 BlockDriverState
*bdrv_find_overlay(BlockDriverState
*active
,
5629 BlockDriverState
*bs
)
5632 GLOBAL_STATE_CODE();
5634 bs
= bdrv_skip_filters(bs
);
5635 active
= bdrv_skip_filters(active
);
5638 BlockDriverState
*next
= bdrv_backing_chain_next(active
);
5648 /* Given a BDS, searches for the base layer. */
5649 BlockDriverState
*bdrv_find_base(BlockDriverState
*bs
)
5651 GLOBAL_STATE_CODE();
5653 return bdrv_find_overlay(bs
, NULL
);
5657 * Return true if at least one of the COW (backing) and filter links
5658 * between @bs and @base is frozen. @errp is set if that's the case.
5659 * @base must be reachable from @bs, or NULL.
5661 bool bdrv_is_backing_chain_frozen(BlockDriverState
*bs
, BlockDriverState
*base
,
5664 BlockDriverState
*i
;
5667 GLOBAL_STATE_CODE();
5669 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5670 child
= bdrv_filter_or_cow_child(i
);
5672 if (child
&& child
->frozen
) {
5673 error_setg(errp
, "Cannot change '%s' link from '%s' to '%s'",
5674 child
->name
, i
->node_name
, child
->bs
->node_name
);
5683 * Freeze all COW (backing) and filter links between @bs and @base.
5684 * If any of the links is already frozen the operation is aborted and
5685 * none of the links are modified.
5686 * @base must be reachable from @bs, or NULL.
5687 * Returns 0 on success. On failure returns < 0 and sets @errp.
5689 int bdrv_freeze_backing_chain(BlockDriverState
*bs
, BlockDriverState
*base
,
5692 BlockDriverState
*i
;
5695 GLOBAL_STATE_CODE();
5697 if (bdrv_is_backing_chain_frozen(bs
, base
, errp
)) {
5701 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5702 child
= bdrv_filter_or_cow_child(i
);
5703 if (child
&& child
->bs
->never_freeze
) {
5704 error_setg(errp
, "Cannot freeze '%s' link to '%s'",
5705 child
->name
, child
->bs
->node_name
);
5710 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5711 child
= bdrv_filter_or_cow_child(i
);
5713 child
->frozen
= true;
5721 * Unfreeze all COW (backing) and filter links between @bs and @base.
5722 * The caller must ensure that all links are frozen before using this
5724 * @base must be reachable from @bs, or NULL.
5726 void bdrv_unfreeze_backing_chain(BlockDriverState
*bs
, BlockDriverState
*base
)
5728 BlockDriverState
*i
;
5731 GLOBAL_STATE_CODE();
5733 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5734 child
= bdrv_filter_or_cow_child(i
);
5736 assert(child
->frozen
);
5737 child
->frozen
= false;
5743 * Drops images above 'base' up to and including 'top', and sets the image
5744 * above 'top' to have base as its backing file.
5746 * Requires that the overlay to 'top' is opened r/w, so that the backing file
5747 * information in 'bs' can be properly updated.
5749 * E.g., this will convert the following chain:
5750 * bottom <- base <- intermediate <- top <- active
5754 * bottom <- base <- active
5756 * It is allowed for bottom==base, in which case it converts:
5758 * base <- intermediate <- top <- active
5764 * If backing_file_str is non-NULL, it will be used when modifying top's
5765 * overlay image metadata.
5768 * if active == top, that is considered an error
5771 int bdrv_drop_intermediate(BlockDriverState
*top
, BlockDriverState
*base
,
5772 const char *backing_file_str
)
5774 BlockDriverState
*explicit_top
= top
;
5775 bool update_inherits_from
;
5777 Error
*local_err
= NULL
;
5779 g_autoptr(GSList
) updated_children
= NULL
;
5782 GLOBAL_STATE_CODE();
5785 bdrv_drained_begin(base
);
5787 if (!top
->drv
|| !base
->drv
) {
5791 /* Make sure that base is in the backing chain of top */
5792 if (!bdrv_chain_contains(top
, base
)) {
5796 /* If 'base' recursively inherits from 'top' then we should set
5797 * base->inherits_from to top->inherits_from after 'top' and all
5798 * other intermediate nodes have been dropped.
5799 * If 'top' is an implicit node (e.g. "commit_top") we should skip
5800 * it because no one inherits from it. We use explicit_top for that. */
5801 explicit_top
= bdrv_skip_implicit_filters(explicit_top
);
5802 update_inherits_from
= bdrv_inherits_from_recursive(base
, explicit_top
);
5804 /* success - we can delete the intermediate states, and link top->base */
5805 if (!backing_file_str
) {
5806 bdrv_refresh_filename(base
);
5807 backing_file_str
= base
->filename
;
5810 QLIST_FOREACH(c
, &top
->parents
, next_parent
) {
5811 updated_children
= g_slist_prepend(updated_children
, c
);
5815 * It seems correct to pass detach_subchain=true here, but it triggers
5816 * one more yet not fixed bug, when due to nested aio_poll loop we switch to
5817 * another drained section, which modify the graph (for example, removing
5818 * the child, which we keep in updated_children list). So, it's a TODO.
5820 * Note, bug triggered if pass detach_subchain=true here and run
5821 * test-bdrv-drain. test_drop_intermediate_poll() test-case will crash.
5824 bdrv_replace_node_common(top
, base
, false, false, &local_err
);
5826 error_report_err(local_err
);
5830 for (p
= updated_children
; p
; p
= p
->next
) {
5833 if (c
->klass
->update_filename
) {
5834 ret
= c
->klass
->update_filename(c
, base
, backing_file_str
,
5838 * TODO: Actually, we want to rollback all previous iterations
5839 * of this loop, and (which is almost impossible) previous
5840 * bdrv_replace_node()...
5842 * Note, that c->klass->update_filename may lead to permission
5843 * update, so it's a bad idea to call it inside permission
5844 * update transaction of bdrv_replace_node.
5846 error_report_err(local_err
);
5852 if (update_inherits_from
) {
5853 base
->inherits_from
= explicit_top
->inherits_from
;
5858 bdrv_drained_end(base
);
5864 * Implementation of BlockDriver.bdrv_co_get_allocated_file_size() that
5865 * sums the size of all data-bearing children. (This excludes backing
5868 static int64_t coroutine_fn GRAPH_RDLOCK
5869 bdrv_sum_allocated_file_size(BlockDriverState
*bs
)
5872 int64_t child_size
, sum
= 0;
5874 QLIST_FOREACH(child
, &bs
->children
, next
) {
5875 if (child
->role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
|
5876 BDRV_CHILD_FILTERED
))
5878 child_size
= bdrv_co_get_allocated_file_size(child
->bs
);
5879 if (child_size
< 0) {
5890 * Length of a allocated file in bytes. Sparse files are counted by actual
5891 * allocated space. Return < 0 if error or unknown.
5893 int64_t coroutine_fn
bdrv_co_get_allocated_file_size(BlockDriverState
*bs
)
5895 BlockDriver
*drv
= bs
->drv
;
5897 assert_bdrv_graph_readable();
5902 if (drv
->bdrv_co_get_allocated_file_size
) {
5903 return drv
->bdrv_co_get_allocated_file_size(bs
);
5906 if (drv
->bdrv_file_open
) {
5908 * Protocol drivers default to -ENOTSUP (most of their data is
5909 * not stored in any of their children (if they even have any),
5910 * so there is no generic way to figure it out).
5913 } else if (drv
->is_filter
) {
5914 /* Filter drivers default to the size of their filtered child */
5915 return bdrv_co_get_allocated_file_size(bdrv_filter_bs(bs
));
5917 /* Other drivers default to summing their children's sizes */
5918 return bdrv_sum_allocated_file_size(bs
);
5924 * @drv: Format driver
5925 * @opts: Creation options for new image
5926 * @in_bs: Existing image containing data for new image (may be NULL)
5927 * @errp: Error object
5928 * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo())
5931 * Calculate file size required to create a new image.
5933 * If @in_bs is given then space for allocated clusters and zero clusters
5934 * from that image are included in the calculation. If @opts contains a
5935 * backing file that is shared by @in_bs then backing clusters may be omitted
5936 * from the calculation.
5938 * If @in_bs is NULL then the calculation includes no allocated clusters
5939 * unless a preallocation option is given in @opts.
5941 * Note that @in_bs may use a different BlockDriver from @drv.
5943 * If an error occurs the @errp pointer is set.
5945 BlockMeasureInfo
*bdrv_measure(BlockDriver
*drv
, QemuOpts
*opts
,
5946 BlockDriverState
*in_bs
, Error
**errp
)
5949 if (!drv
->bdrv_measure
) {
5950 error_setg(errp
, "Block driver '%s' does not support size measurement",
5955 return drv
->bdrv_measure(opts
, in_bs
, errp
);
5959 * Return number of sectors on success, -errno on error.
5961 int64_t coroutine_fn
bdrv_co_nb_sectors(BlockDriverState
*bs
)
5963 BlockDriver
*drv
= bs
->drv
;
5965 assert_bdrv_graph_readable();
5970 if (bs
->bl
.has_variable_length
) {
5971 int ret
= bdrv_co_refresh_total_sectors(bs
, bs
->total_sectors
);
5976 return bs
->total_sectors
;
5980 * This wrapper is written by hand because this function is in the hot I/O path,
5981 * via blk_get_geometry.
5983 int64_t coroutine_mixed_fn
bdrv_nb_sectors(BlockDriverState
*bs
)
5985 BlockDriver
*drv
= bs
->drv
;
5991 if (bs
->bl
.has_variable_length
) {
5992 int ret
= bdrv_refresh_total_sectors(bs
, bs
->total_sectors
);
5998 return bs
->total_sectors
;
6002 * Return length in bytes on success, -errno on error.
6003 * The length is always a multiple of BDRV_SECTOR_SIZE.
6005 int64_t coroutine_fn
bdrv_co_getlength(BlockDriverState
*bs
)
6009 assert_bdrv_graph_readable();
6011 ret
= bdrv_co_nb_sectors(bs
);
6015 if (ret
> INT64_MAX
/ BDRV_SECTOR_SIZE
) {
6018 return ret
* BDRV_SECTOR_SIZE
;
6021 bool bdrv_is_sg(BlockDriverState
*bs
)
6028 * Return whether the given node supports compressed writes.
6030 bool bdrv_supports_compressed_writes(BlockDriverState
*bs
)
6032 BlockDriverState
*filtered
;
6035 if (!bs
->drv
|| !block_driver_can_compress(bs
->drv
)) {
6039 filtered
= bdrv_filter_bs(bs
);
6042 * Filters can only forward compressed writes, so we have to
6045 return bdrv_supports_compressed_writes(filtered
);
6051 const char *bdrv_get_format_name(BlockDriverState
*bs
)
6054 return bs
->drv
? bs
->drv
->format_name
: NULL
;
6057 static int qsort_strcmp(const void *a
, const void *b
)
6059 return strcmp(*(char *const *)a
, *(char *const *)b
);
6062 void bdrv_iterate_format(void (*it
)(void *opaque
, const char *name
),
6063 void *opaque
, bool read_only
)
6068 const char **formats
= NULL
;
6070 GLOBAL_STATE_CODE();
6072 QLIST_FOREACH(drv
, &bdrv_drivers
, list
) {
6073 if (drv
->format_name
) {
6077 if (use_bdrv_whitelist
&& !bdrv_is_whitelisted(drv
, read_only
)) {
6081 while (formats
&& i
&& !found
) {
6082 found
= !strcmp(formats
[--i
], drv
->format_name
);
6086 formats
= g_renew(const char *, formats
, count
+ 1);
6087 formats
[count
++] = drv
->format_name
;
6092 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); i
++) {
6093 const char *format_name
= block_driver_modules
[i
].format_name
;
6099 if (use_bdrv_whitelist
&&
6100 !bdrv_format_is_whitelisted(format_name
, read_only
)) {
6104 while (formats
&& j
&& !found
) {
6105 found
= !strcmp(formats
[--j
], format_name
);
6109 formats
= g_renew(const char *, formats
, count
+ 1);
6110 formats
[count
++] = format_name
;
6115 qsort(formats
, count
, sizeof(formats
[0]), qsort_strcmp
);
6117 for (i
= 0; i
< count
; i
++) {
6118 it(opaque
, formats
[i
]);
6124 /* This function is to find a node in the bs graph */
6125 BlockDriverState
*bdrv_find_node(const char *node_name
)
6127 BlockDriverState
*bs
;
6130 GLOBAL_STATE_CODE();
6132 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
6133 if (!strcmp(node_name
, bs
->node_name
)) {
6140 /* Put this QMP function here so it can access the static graph_bdrv_states. */
6141 BlockDeviceInfoList
*bdrv_named_nodes_list(bool flat
,
6144 BlockDeviceInfoList
*list
;
6145 BlockDriverState
*bs
;
6147 GLOBAL_STATE_CODE();
6150 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
6151 BlockDeviceInfo
*info
= bdrv_block_device_info(NULL
, bs
, flat
, errp
);
6153 qapi_free_BlockDeviceInfoList(list
);
6156 QAPI_LIST_PREPEND(list
, info
);
6162 typedef struct XDbgBlockGraphConstructor
{
6163 XDbgBlockGraph
*graph
;
6164 GHashTable
*graph_nodes
;
6165 } XDbgBlockGraphConstructor
;
6167 static XDbgBlockGraphConstructor
*xdbg_graph_new(void)
6169 XDbgBlockGraphConstructor
*gr
= g_new(XDbgBlockGraphConstructor
, 1);
6171 gr
->graph
= g_new0(XDbgBlockGraph
, 1);
6172 gr
->graph_nodes
= g_hash_table_new(NULL
, NULL
);
6177 static XDbgBlockGraph
*xdbg_graph_finalize(XDbgBlockGraphConstructor
*gr
)
6179 XDbgBlockGraph
*graph
= gr
->graph
;
6181 g_hash_table_destroy(gr
->graph_nodes
);
6187 static uintptr_t xdbg_graph_node_num(XDbgBlockGraphConstructor
*gr
, void *node
)
6189 uintptr_t ret
= (uintptr_t)g_hash_table_lookup(gr
->graph_nodes
, node
);
6196 * Start counting from 1, not 0, because 0 interferes with not-found (NULL)
6197 * answer of g_hash_table_lookup.
6199 ret
= g_hash_table_size(gr
->graph_nodes
) + 1;
6200 g_hash_table_insert(gr
->graph_nodes
, node
, (void *)ret
);
6205 static void xdbg_graph_add_node(XDbgBlockGraphConstructor
*gr
, void *node
,
6206 XDbgBlockGraphNodeType type
, const char *name
)
6208 XDbgBlockGraphNode
*n
;
6210 n
= g_new0(XDbgBlockGraphNode
, 1);
6212 n
->id
= xdbg_graph_node_num(gr
, node
);
6214 n
->name
= g_strdup(name
);
6216 QAPI_LIST_PREPEND(gr
->graph
->nodes
, n
);
6219 static void xdbg_graph_add_edge(XDbgBlockGraphConstructor
*gr
, void *parent
,
6220 const BdrvChild
*child
)
6222 BlockPermission qapi_perm
;
6223 XDbgBlockGraphEdge
*edge
;
6224 GLOBAL_STATE_CODE();
6226 edge
= g_new0(XDbgBlockGraphEdge
, 1);
6228 edge
->parent
= xdbg_graph_node_num(gr
, parent
);
6229 edge
->child
= xdbg_graph_node_num(gr
, child
->bs
);
6230 edge
->name
= g_strdup(child
->name
);
6232 for (qapi_perm
= 0; qapi_perm
< BLOCK_PERMISSION__MAX
; qapi_perm
++) {
6233 uint64_t flag
= bdrv_qapi_perm_to_blk_perm(qapi_perm
);
6235 if (flag
& child
->perm
) {
6236 QAPI_LIST_PREPEND(edge
->perm
, qapi_perm
);
6238 if (flag
& child
->shared_perm
) {
6239 QAPI_LIST_PREPEND(edge
->shared_perm
, qapi_perm
);
6243 QAPI_LIST_PREPEND(gr
->graph
->edges
, edge
);
6247 XDbgBlockGraph
*bdrv_get_xdbg_block_graph(Error
**errp
)
6251 BlockDriverState
*bs
;
6253 XDbgBlockGraphConstructor
*gr
= xdbg_graph_new();
6255 GLOBAL_STATE_CODE();
6257 for (blk
= blk_all_next(NULL
); blk
; blk
= blk_all_next(blk
)) {
6258 char *allocated_name
= NULL
;
6259 const char *name
= blk_name(blk
);
6262 name
= allocated_name
= blk_get_attached_dev_id(blk
);
6264 xdbg_graph_add_node(gr
, blk
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND
,
6266 g_free(allocated_name
);
6267 if (blk_root(blk
)) {
6268 xdbg_graph_add_edge(gr
, blk
, blk_root(blk
));
6272 WITH_JOB_LOCK_GUARD() {
6273 for (job
= block_job_next_locked(NULL
); job
;
6274 job
= block_job_next_locked(job
)) {
6277 xdbg_graph_add_node(gr
, job
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB
,
6279 for (el
= job
->nodes
; el
; el
= el
->next
) {
6280 xdbg_graph_add_edge(gr
, job
, (BdrvChild
*)el
->data
);
6285 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
6286 xdbg_graph_add_node(gr
, bs
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_DRIVER
,
6288 QLIST_FOREACH(child
, &bs
->children
, next
) {
6289 xdbg_graph_add_edge(gr
, bs
, child
);
6293 return xdbg_graph_finalize(gr
);
6296 BlockDriverState
*bdrv_lookup_bs(const char *device
,
6297 const char *node_name
,
6301 BlockDriverState
*bs
;
6303 GLOBAL_STATE_CODE();
6306 blk
= blk_by_name(device
);
6311 error_setg(errp
, "Device '%s' has no medium", device
);
6319 bs
= bdrv_find_node(node_name
);
6326 error_setg(errp
, "Cannot find device=\'%s\' nor node-name=\'%s\'",
6327 device
? device
: "",
6328 node_name
? node_name
: "");
6332 /* If 'base' is in the same chain as 'top', return true. Otherwise,
6333 * return false. If either argument is NULL, return false. */
6334 bool bdrv_chain_contains(BlockDriverState
*top
, BlockDriverState
*base
)
6337 GLOBAL_STATE_CODE();
6339 while (top
&& top
!= base
) {
6340 top
= bdrv_filter_or_cow_bs(top
);
6346 BlockDriverState
*bdrv_next_node(BlockDriverState
*bs
)
6348 GLOBAL_STATE_CODE();
6350 return QTAILQ_FIRST(&graph_bdrv_states
);
6352 return QTAILQ_NEXT(bs
, node_list
);
6355 BlockDriverState
*bdrv_next_all_states(BlockDriverState
*bs
)
6357 GLOBAL_STATE_CODE();
6359 return QTAILQ_FIRST(&all_bdrv_states
);
6361 return QTAILQ_NEXT(bs
, bs_list
);
6364 const char *bdrv_get_node_name(const BlockDriverState
*bs
)
6367 return bs
->node_name
;
6370 const char *bdrv_get_parent_name(const BlockDriverState
*bs
)
6376 /* If multiple parents have a name, just pick the first one. */
6377 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
6378 if (c
->klass
->get_name
) {
6379 name
= c
->klass
->get_name(c
);
6380 if (name
&& *name
) {
6389 /* TODO check what callers really want: bs->node_name or blk_name() */
6390 const char *bdrv_get_device_name(const BlockDriverState
*bs
)
6393 return bdrv_get_parent_name(bs
) ?: "";
6396 /* This can be used to identify nodes that might not have a device
6397 * name associated. Since node and device names live in the same
6398 * namespace, the result is unambiguous. The exception is if both are
6399 * absent, then this returns an empty (non-null) string. */
6400 const char *bdrv_get_device_or_node_name(const BlockDriverState
*bs
)
6403 return bdrv_get_parent_name(bs
) ?: bs
->node_name
;
6406 int bdrv_get_flags(BlockDriverState
*bs
)
6409 return bs
->open_flags
;
6412 int bdrv_has_zero_init_1(BlockDriverState
*bs
)
6414 GLOBAL_STATE_CODE();
6418 int bdrv_has_zero_init(BlockDriverState
*bs
)
6420 BlockDriverState
*filtered
;
6421 GLOBAL_STATE_CODE();
6427 /* If BS is a copy on write image, it is initialized to
6428 the contents of the base image, which may not be zeroes. */
6429 if (bdrv_cow_child(bs
)) {
6432 if (bs
->drv
->bdrv_has_zero_init
) {
6433 return bs
->drv
->bdrv_has_zero_init(bs
);
6436 filtered
= bdrv_filter_bs(bs
);
6438 return bdrv_has_zero_init(filtered
);
6445 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState
*bs
)
6448 if (!(bs
->open_flags
& BDRV_O_UNMAP
)) {
6452 return bs
->supported_zero_flags
& BDRV_REQ_MAY_UNMAP
;
6455 void bdrv_get_backing_filename(BlockDriverState
*bs
,
6456 char *filename
, int filename_size
)
6459 pstrcpy(filename
, filename_size
, bs
->backing_file
);
6462 int coroutine_fn
bdrv_co_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
6465 BlockDriver
*drv
= bs
->drv
;
6467 assert_bdrv_graph_readable();
6469 /* if bs->drv == NULL, bs is closed, so there's nothing to do here */
6473 if (!drv
->bdrv_co_get_info
) {
6474 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
6476 return bdrv_co_get_info(filtered
, bdi
);
6480 memset(bdi
, 0, sizeof(*bdi
));
6481 ret
= drv
->bdrv_co_get_info(bs
, bdi
);
6486 if (bdi
->cluster_size
> BDRV_MAX_ALIGNMENT
) {
6493 ImageInfoSpecific
*bdrv_get_specific_info(BlockDriverState
*bs
,
6496 BlockDriver
*drv
= bs
->drv
;
6498 if (drv
&& drv
->bdrv_get_specific_info
) {
6499 return drv
->bdrv_get_specific_info(bs
, errp
);
6504 BlockStatsSpecific
*bdrv_get_specific_stats(BlockDriverState
*bs
)
6506 BlockDriver
*drv
= bs
->drv
;
6508 if (!drv
|| !drv
->bdrv_get_specific_stats
) {
6511 return drv
->bdrv_get_specific_stats(bs
);
6514 void coroutine_fn
bdrv_co_debug_event(BlockDriverState
*bs
, BlkdebugEvent event
)
6517 assert_bdrv_graph_readable();
6519 if (!bs
|| !bs
->drv
|| !bs
->drv
->bdrv_co_debug_event
) {
6523 bs
->drv
->bdrv_co_debug_event(bs
, event
);
6526 static BlockDriverState
*bdrv_find_debug_node(BlockDriverState
*bs
)
6528 GLOBAL_STATE_CODE();
6529 while (bs
&& bs
->drv
&& !bs
->drv
->bdrv_debug_breakpoint
) {
6530 bs
= bdrv_primary_bs(bs
);
6533 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_breakpoint
) {
6534 assert(bs
->drv
->bdrv_debug_remove_breakpoint
);
6541 int bdrv_debug_breakpoint(BlockDriverState
*bs
, const char *event
,
6544 GLOBAL_STATE_CODE();
6545 bs
= bdrv_find_debug_node(bs
);
6547 return bs
->drv
->bdrv_debug_breakpoint(bs
, event
, tag
);
6553 int bdrv_debug_remove_breakpoint(BlockDriverState
*bs
, const char *tag
)
6555 GLOBAL_STATE_CODE();
6556 bs
= bdrv_find_debug_node(bs
);
6558 return bs
->drv
->bdrv_debug_remove_breakpoint(bs
, tag
);
6564 int bdrv_debug_resume(BlockDriverState
*bs
, const char *tag
)
6566 GLOBAL_STATE_CODE();
6567 while (bs
&& (!bs
->drv
|| !bs
->drv
->bdrv_debug_resume
)) {
6568 bs
= bdrv_primary_bs(bs
);
6571 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_resume
) {
6572 return bs
->drv
->bdrv_debug_resume(bs
, tag
);
6578 bool bdrv_debug_is_suspended(BlockDriverState
*bs
, const char *tag
)
6580 GLOBAL_STATE_CODE();
6581 while (bs
&& bs
->drv
&& !bs
->drv
->bdrv_debug_is_suspended
) {
6582 bs
= bdrv_primary_bs(bs
);
6585 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_is_suspended
) {
6586 return bs
->drv
->bdrv_debug_is_suspended(bs
, tag
);
6592 /* backing_file can either be relative, or absolute, or a protocol. If it is
6593 * relative, it must be relative to the chain. So, passing in bs->filename
6594 * from a BDS as backing_file should not be done, as that may be relative to
6595 * the CWD rather than the chain. */
6596 BlockDriverState
*bdrv_find_backing_image(BlockDriverState
*bs
,
6597 const char *backing_file
)
6599 char *filename_full
= NULL
;
6600 char *backing_file_full
= NULL
;
6601 char *filename_tmp
= NULL
;
6602 int is_protocol
= 0;
6603 bool filenames_refreshed
= false;
6604 BlockDriverState
*curr_bs
= NULL
;
6605 BlockDriverState
*retval
= NULL
;
6606 BlockDriverState
*bs_below
;
6608 GLOBAL_STATE_CODE();
6610 if (!bs
|| !bs
->drv
|| !backing_file
) {
6614 filename_full
= g_malloc(PATH_MAX
);
6615 backing_file_full
= g_malloc(PATH_MAX
);
6617 is_protocol
= path_has_protocol(backing_file
);
6620 * Being largely a legacy function, skip any filters here
6621 * (because filters do not have normal filenames, so they cannot
6622 * match anyway; and allowing json:{} filenames is a bit out of
6625 for (curr_bs
= bdrv_skip_filters(bs
);
6626 bdrv_cow_child(curr_bs
) != NULL
;
6629 bs_below
= bdrv_backing_chain_next(curr_bs
);
6631 if (bdrv_backing_overridden(curr_bs
)) {
6633 * If the backing file was overridden, we can only compare
6634 * directly against the backing node's filename.
6637 if (!filenames_refreshed
) {
6639 * This will automatically refresh all of the
6640 * filenames in the rest of the backing chain, so we
6641 * only need to do this once.
6643 bdrv_refresh_filename(bs_below
);
6644 filenames_refreshed
= true;
6647 if (strcmp(backing_file
, bs_below
->filename
) == 0) {
6651 } else if (is_protocol
|| path_has_protocol(curr_bs
->backing_file
)) {
6653 * If either of the filename paths is actually a protocol, then
6654 * compare unmodified paths; otherwise make paths relative.
6656 char *backing_file_full_ret
;
6658 if (strcmp(backing_file
, curr_bs
->backing_file
) == 0) {
6662 /* Also check against the full backing filename for the image */
6663 backing_file_full_ret
= bdrv_get_full_backing_filename(curr_bs
,
6665 if (backing_file_full_ret
) {
6666 bool equal
= strcmp(backing_file
, backing_file_full_ret
) == 0;
6667 g_free(backing_file_full_ret
);
6674 /* If not an absolute filename path, make it relative to the current
6675 * image's filename path */
6676 filename_tmp
= bdrv_make_absolute_filename(curr_bs
, backing_file
,
6678 /* We are going to compare canonicalized absolute pathnames */
6679 if (!filename_tmp
|| !realpath(filename_tmp
, filename_full
)) {
6680 g_free(filename_tmp
);
6683 g_free(filename_tmp
);
6685 /* We need to make sure the backing filename we are comparing against
6686 * is relative to the current image filename (or absolute) */
6687 filename_tmp
= bdrv_get_full_backing_filename(curr_bs
, NULL
);
6688 if (!filename_tmp
|| !realpath(filename_tmp
, backing_file_full
)) {
6689 g_free(filename_tmp
);
6692 g_free(filename_tmp
);
6694 if (strcmp(backing_file_full
, filename_full
) == 0) {
6701 g_free(filename_full
);
6702 g_free(backing_file_full
);
6706 void bdrv_init(void)
6708 #ifdef CONFIG_BDRV_WHITELIST_TOOLS
6709 use_bdrv_whitelist
= 1;
6711 module_call_init(MODULE_INIT_BLOCK
);
6714 void bdrv_init_with_whitelist(void)
6716 use_bdrv_whitelist
= 1;
6720 int bdrv_activate(BlockDriverState
*bs
, Error
**errp
)
6722 BdrvChild
*child
, *parent
;
6723 Error
*local_err
= NULL
;
6725 BdrvDirtyBitmap
*bm
;
6727 GLOBAL_STATE_CODE();
6733 QLIST_FOREACH(child
, &bs
->children
, next
) {
6734 bdrv_activate(child
->bs
, &local_err
);
6736 error_propagate(errp
, local_err
);
6742 * Update permissions, they may differ for inactive nodes.
6744 * Note that the required permissions of inactive images are always a
6745 * subset of the permissions required after activating the image. This
6746 * allows us to just get the permissions upfront without restricting
6747 * bdrv_co_invalidate_cache().
6749 * It also means that in error cases, we don't have to try and revert to
6750 * the old permissions (which is an operation that could fail, too). We can
6751 * just keep the extended permissions for the next time that an activation
6752 * of the image is tried.
6754 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
6755 bs
->open_flags
&= ~BDRV_O_INACTIVE
;
6756 ret
= bdrv_refresh_perms(bs
, NULL
, errp
);
6758 bs
->open_flags
|= BDRV_O_INACTIVE
;
6762 ret
= bdrv_invalidate_cache(bs
, errp
);
6764 bs
->open_flags
|= BDRV_O_INACTIVE
;
6768 FOR_EACH_DIRTY_BITMAP(bs
, bm
) {
6769 bdrv_dirty_bitmap_skip_store(bm
, false);
6772 ret
= bdrv_refresh_total_sectors(bs
, bs
->total_sectors
);
6774 bs
->open_flags
|= BDRV_O_INACTIVE
;
6775 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
6780 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6781 if (parent
->klass
->activate
) {
6782 parent
->klass
->activate(parent
, &local_err
);
6784 bs
->open_flags
|= BDRV_O_INACTIVE
;
6785 error_propagate(errp
, local_err
);
6794 int coroutine_fn
bdrv_co_invalidate_cache(BlockDriverState
*bs
, Error
**errp
)
6796 Error
*local_err
= NULL
;
6799 assert(!(bs
->open_flags
& BDRV_O_INACTIVE
));
6800 assert_bdrv_graph_readable();
6802 if (bs
->drv
->bdrv_co_invalidate_cache
) {
6803 bs
->drv
->bdrv_co_invalidate_cache(bs
, &local_err
);
6805 error_propagate(errp
, local_err
);
6813 void bdrv_activate_all(Error
**errp
)
6815 BlockDriverState
*bs
;
6816 BdrvNextIterator it
;
6818 GLOBAL_STATE_CODE();
6820 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
6821 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
6824 aio_context_acquire(aio_context
);
6825 ret
= bdrv_activate(bs
, errp
);
6826 aio_context_release(aio_context
);
6828 bdrv_next_cleanup(&it
);
6834 static bool bdrv_has_bds_parent(BlockDriverState
*bs
, bool only_active
)
6837 GLOBAL_STATE_CODE();
6839 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6840 if (parent
->klass
->parent_is_bds
) {
6841 BlockDriverState
*parent_bs
= parent
->opaque
;
6842 if (!only_active
|| !(parent_bs
->open_flags
& BDRV_O_INACTIVE
)) {
6851 static int bdrv_inactivate_recurse(BlockDriverState
*bs
)
6853 BdrvChild
*child
, *parent
;
6855 uint64_t cumulative_perms
, cumulative_shared_perms
;
6857 GLOBAL_STATE_CODE();
6863 /* Make sure that we don't inactivate a child before its parent.
6864 * It will be covered by recursion from the yet active parent. */
6865 if (bdrv_has_bds_parent(bs
, true)) {
6869 assert(!(bs
->open_flags
& BDRV_O_INACTIVE
));
6871 /* Inactivate this node */
6872 if (bs
->drv
->bdrv_inactivate
) {
6873 ret
= bs
->drv
->bdrv_inactivate(bs
);
6879 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6880 if (parent
->klass
->inactivate
) {
6881 ret
= parent
->klass
->inactivate(parent
);
6888 bdrv_get_cumulative_perm(bs
, &cumulative_perms
,
6889 &cumulative_shared_perms
);
6890 if (cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) {
6891 /* Our inactive parents still need write access. Inactivation failed. */
6895 bs
->open_flags
|= BDRV_O_INACTIVE
;
6898 * Update permissions, they may differ for inactive nodes.
6899 * We only tried to loosen restrictions, so errors are not fatal, ignore
6902 bdrv_refresh_perms(bs
, NULL
, NULL
);
6904 /* Recursively inactivate children */
6905 QLIST_FOREACH(child
, &bs
->children
, next
) {
6906 ret
= bdrv_inactivate_recurse(child
->bs
);
6915 int bdrv_inactivate_all(void)
6917 BlockDriverState
*bs
= NULL
;
6918 BdrvNextIterator it
;
6920 GSList
*aio_ctxs
= NULL
, *ctx
;
6922 GLOBAL_STATE_CODE();
6924 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
6925 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
6927 if (!g_slist_find(aio_ctxs
, aio_context
)) {
6928 aio_ctxs
= g_slist_prepend(aio_ctxs
, aio_context
);
6929 aio_context_acquire(aio_context
);
6933 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
6934 /* Nodes with BDS parents are covered by recursion from the last
6935 * parent that gets inactivated. Don't inactivate them a second
6936 * time if that has already happened. */
6937 if (bdrv_has_bds_parent(bs
, false)) {
6940 ret
= bdrv_inactivate_recurse(bs
);
6942 bdrv_next_cleanup(&it
);
6948 for (ctx
= aio_ctxs
; ctx
!= NULL
; ctx
= ctx
->next
) {
6949 AioContext
*aio_context
= ctx
->data
;
6950 aio_context_release(aio_context
);
6952 g_slist_free(aio_ctxs
);
6957 /**************************************************************/
6958 /* removable device support */
6961 * Return TRUE if the media is present
6963 bool coroutine_fn
bdrv_co_is_inserted(BlockDriverState
*bs
)
6965 BlockDriver
*drv
= bs
->drv
;
6968 assert_bdrv_graph_readable();
6973 if (drv
->bdrv_co_is_inserted
) {
6974 return drv
->bdrv_co_is_inserted(bs
);
6976 QLIST_FOREACH(child
, &bs
->children
, next
) {
6977 if (!bdrv_co_is_inserted(child
->bs
)) {
6985 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
6987 void coroutine_fn
bdrv_co_eject(BlockDriverState
*bs
, bool eject_flag
)
6989 BlockDriver
*drv
= bs
->drv
;
6991 assert_bdrv_graph_readable();
6993 if (drv
&& drv
->bdrv_co_eject
) {
6994 drv
->bdrv_co_eject(bs
, eject_flag
);
6999 * Lock or unlock the media (if it is locked, the user won't be able
7000 * to eject it manually).
7002 void coroutine_fn
bdrv_co_lock_medium(BlockDriverState
*bs
, bool locked
)
7004 BlockDriver
*drv
= bs
->drv
;
7006 assert_bdrv_graph_readable();
7007 trace_bdrv_lock_medium(bs
, locked
);
7009 if (drv
&& drv
->bdrv_co_lock_medium
) {
7010 drv
->bdrv_co_lock_medium(bs
, locked
);
7014 /* Get a reference to bs */
7015 void bdrv_ref(BlockDriverState
*bs
)
7017 GLOBAL_STATE_CODE();
7021 /* Release a previously grabbed reference to bs.
7022 * If after releasing, reference count is zero, the BlockDriverState is
7024 void bdrv_unref(BlockDriverState
*bs
)
7026 GLOBAL_STATE_CODE();
7030 assert(bs
->refcnt
> 0);
7031 if (--bs
->refcnt
== 0) {
7036 struct BdrvOpBlocker
{
7038 QLIST_ENTRY(BdrvOpBlocker
) list
;
7041 bool bdrv_op_is_blocked(BlockDriverState
*bs
, BlockOpType op
, Error
**errp
)
7043 BdrvOpBlocker
*blocker
;
7044 GLOBAL_STATE_CODE();
7045 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
7046 if (!QLIST_EMPTY(&bs
->op_blockers
[op
])) {
7047 blocker
= QLIST_FIRST(&bs
->op_blockers
[op
]);
7048 error_propagate_prepend(errp
, error_copy(blocker
->reason
),
7049 "Node '%s' is busy: ",
7050 bdrv_get_device_or_node_name(bs
));
7056 void bdrv_op_block(BlockDriverState
*bs
, BlockOpType op
, Error
*reason
)
7058 BdrvOpBlocker
*blocker
;
7059 GLOBAL_STATE_CODE();
7060 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
7062 blocker
= g_new0(BdrvOpBlocker
, 1);
7063 blocker
->reason
= reason
;
7064 QLIST_INSERT_HEAD(&bs
->op_blockers
[op
], blocker
, list
);
7067 void bdrv_op_unblock(BlockDriverState
*bs
, BlockOpType op
, Error
*reason
)
7069 BdrvOpBlocker
*blocker
, *next
;
7070 GLOBAL_STATE_CODE();
7071 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
7072 QLIST_FOREACH_SAFE(blocker
, &bs
->op_blockers
[op
], list
, next
) {
7073 if (blocker
->reason
== reason
) {
7074 QLIST_REMOVE(blocker
, list
);
7080 void bdrv_op_block_all(BlockDriverState
*bs
, Error
*reason
)
7083 GLOBAL_STATE_CODE();
7084 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
7085 bdrv_op_block(bs
, i
, reason
);
7089 void bdrv_op_unblock_all(BlockDriverState
*bs
, Error
*reason
)
7092 GLOBAL_STATE_CODE();
7093 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
7094 bdrv_op_unblock(bs
, i
, reason
);
7098 bool bdrv_op_blocker_is_empty(BlockDriverState
*bs
)
7101 GLOBAL_STATE_CODE();
7102 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
7103 if (!QLIST_EMPTY(&bs
->op_blockers
[i
])) {
7111 * Must not be called while holding the lock of an AioContext other than the
7114 void bdrv_img_create(const char *filename
, const char *fmt
,
7115 const char *base_filename
, const char *base_fmt
,
7116 char *options
, uint64_t img_size
, int flags
, bool quiet
,
7119 QemuOptsList
*create_opts
= NULL
;
7120 QemuOpts
*opts
= NULL
;
7121 const char *backing_fmt
, *backing_file
;
7123 BlockDriver
*drv
, *proto_drv
;
7124 Error
*local_err
= NULL
;
7127 GLOBAL_STATE_CODE();
7129 /* Find driver and parse its options */
7130 drv
= bdrv_find_format(fmt
);
7132 error_setg(errp
, "Unknown file format '%s'", fmt
);
7136 proto_drv
= bdrv_find_protocol(filename
, true, errp
);
7141 if (!drv
->create_opts
) {
7142 error_setg(errp
, "Format driver '%s' does not support image creation",
7147 if (!proto_drv
->create_opts
) {
7148 error_setg(errp
, "Protocol driver '%s' does not support image creation",
7149 proto_drv
->format_name
);
7153 aio_context_acquire(qemu_get_aio_context());
7155 /* Create parameter list */
7156 create_opts
= qemu_opts_append(create_opts
, drv
->create_opts
);
7157 create_opts
= qemu_opts_append(create_opts
, proto_drv
->create_opts
);
7159 opts
= qemu_opts_create(create_opts
, NULL
, 0, &error_abort
);
7161 /* Parse -o options */
7163 if (!qemu_opts_do_parse(opts
, options
, NULL
, errp
)) {
7168 if (!qemu_opt_get(opts
, BLOCK_OPT_SIZE
)) {
7169 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, img_size
, &error_abort
);
7170 } else if (img_size
!= UINT64_C(-1)) {
7171 error_setg(errp
, "The image size must be specified only once");
7175 if (base_filename
) {
7176 if (!qemu_opt_set(opts
, BLOCK_OPT_BACKING_FILE
, base_filename
,
7178 error_setg(errp
, "Backing file not supported for file format '%s'",
7185 if (!qemu_opt_set(opts
, BLOCK_OPT_BACKING_FMT
, base_fmt
, NULL
)) {
7186 error_setg(errp
, "Backing file format not supported for file "
7187 "format '%s'", fmt
);
7192 backing_file
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FILE
);
7194 if (!strcmp(filename
, backing_file
)) {
7195 error_setg(errp
, "Error: Trying to create an image with the "
7196 "same filename as the backing file");
7199 if (backing_file
[0] == '\0') {
7200 error_setg(errp
, "Expected backing file name, got empty string");
7205 backing_fmt
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FMT
);
7207 /* The size for the image must always be specified, unless we have a backing
7208 * file and we have not been forbidden from opening it. */
7209 size
= qemu_opt_get_size(opts
, BLOCK_OPT_SIZE
, img_size
);
7210 if (backing_file
&& !(flags
& BDRV_O_NO_BACKING
)) {
7211 BlockDriverState
*bs
;
7214 QDict
*backing_options
= NULL
;
7217 bdrv_get_full_backing_filename_from_filename(filename
, backing_file
,
7222 assert(full_backing
);
7225 * No need to do I/O here, which allows us to open encrypted
7226 * backing images without needing the secret
7229 back_flags
&= ~(BDRV_O_RDWR
| BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
);
7230 back_flags
|= BDRV_O_NO_IO
;
7232 backing_options
= qdict_new();
7234 qdict_put_str(backing_options
, "driver", backing_fmt
);
7236 qdict_put_bool(backing_options
, BDRV_OPT_FORCE_SHARE
, true);
7238 bs
= bdrv_open(full_backing
, NULL
, backing_options
, back_flags
,
7240 g_free(full_backing
);
7242 error_append_hint(&local_err
, "Could not open backing image.\n");
7246 error_setg(&local_err
,
7247 "Backing file specified without backing format");
7248 error_append_hint(&local_err
, "Detected format of %s.\n",
7249 bs
->drv
->format_name
);
7253 /* Opened BS, have no size */
7254 size
= bdrv_getlength(bs
);
7256 error_setg_errno(errp
, -size
, "Could not get size of '%s'",
7261 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, size
, &error_abort
);
7265 /* (backing_file && !(flags & BDRV_O_NO_BACKING)) */
7266 } else if (backing_file
&& !backing_fmt
) {
7267 error_setg(&local_err
,
7268 "Backing file specified without backing format");
7273 error_setg(errp
, "Image creation needs a size parameter");
7278 printf("Formatting '%s', fmt=%s ", filename
, fmt
);
7279 qemu_opts_print(opts
, " ");
7284 ret
= bdrv_create(drv
, filename
, opts
, &local_err
);
7286 if (ret
== -EFBIG
) {
7287 /* This is generally a better message than whatever the driver would
7288 * deliver (especially because of the cluster_size_hint), since that
7289 * is most probably not much different from "image too large". */
7290 const char *cluster_size_hint
= "";
7291 if (qemu_opt_get_size(opts
, BLOCK_OPT_CLUSTER_SIZE
, 0)) {
7292 cluster_size_hint
= " (try using a larger cluster size)";
7294 error_setg(errp
, "The image size is too large for file format '%s'"
7295 "%s", fmt
, cluster_size_hint
);
7296 error_free(local_err
);
7301 qemu_opts_del(opts
);
7302 qemu_opts_free(create_opts
);
7303 error_propagate(errp
, local_err
);
7304 aio_context_release(qemu_get_aio_context());
7307 AioContext
*bdrv_get_aio_context(BlockDriverState
*bs
)
7310 return bs
? bs
->aio_context
: qemu_get_aio_context();
7313 AioContext
*coroutine_fn
bdrv_co_enter(BlockDriverState
*bs
)
7315 Coroutine
*self
= qemu_coroutine_self();
7316 AioContext
*old_ctx
= qemu_coroutine_get_aio_context(self
);
7317 AioContext
*new_ctx
;
7321 * Increase bs->in_flight to ensure that this operation is completed before
7322 * moving the node to a different AioContext. Read new_ctx only afterwards.
7324 bdrv_inc_in_flight(bs
);
7326 new_ctx
= bdrv_get_aio_context(bs
);
7327 aio_co_reschedule_self(new_ctx
);
7331 void coroutine_fn
bdrv_co_leave(BlockDriverState
*bs
, AioContext
*old_ctx
)
7334 aio_co_reschedule_self(old_ctx
);
7335 bdrv_dec_in_flight(bs
);
7338 void coroutine_fn
bdrv_co_lock(BlockDriverState
*bs
)
7340 AioContext
*ctx
= bdrv_get_aio_context(bs
);
7342 /* In the main thread, bs->aio_context won't change concurrently */
7343 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
7346 * We're in coroutine context, so we already hold the lock of the main
7347 * loop AioContext. Don't lock it twice to avoid deadlocks.
7349 assert(qemu_in_coroutine());
7350 if (ctx
!= qemu_get_aio_context()) {
7351 aio_context_acquire(ctx
);
7355 void coroutine_fn
bdrv_co_unlock(BlockDriverState
*bs
)
7357 AioContext
*ctx
= bdrv_get_aio_context(bs
);
7359 assert(qemu_in_coroutine());
7360 if (ctx
!= qemu_get_aio_context()) {
7361 aio_context_release(ctx
);
7365 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier
*ban
)
7367 GLOBAL_STATE_CODE();
7368 QLIST_REMOVE(ban
, list
);
7372 static void bdrv_detach_aio_context(BlockDriverState
*bs
)
7374 BdrvAioNotifier
*baf
, *baf_tmp
;
7376 assert(!bs
->walking_aio_notifiers
);
7377 GLOBAL_STATE_CODE();
7378 bs
->walking_aio_notifiers
= true;
7379 QLIST_FOREACH_SAFE(baf
, &bs
->aio_notifiers
, list
, baf_tmp
) {
7381 bdrv_do_remove_aio_context_notifier(baf
);
7383 baf
->detach_aio_context(baf
->opaque
);
7386 /* Never mind iterating again to check for ->deleted. bdrv_close() will
7387 * remove remaining aio notifiers if we aren't called again.
7389 bs
->walking_aio_notifiers
= false;
7391 if (bs
->drv
&& bs
->drv
->bdrv_detach_aio_context
) {
7392 bs
->drv
->bdrv_detach_aio_context(bs
);
7395 bs
->aio_context
= NULL
;
7398 static void bdrv_attach_aio_context(BlockDriverState
*bs
,
7399 AioContext
*new_context
)
7401 BdrvAioNotifier
*ban
, *ban_tmp
;
7402 GLOBAL_STATE_CODE();
7404 bs
->aio_context
= new_context
;
7406 if (bs
->drv
&& bs
->drv
->bdrv_attach_aio_context
) {
7407 bs
->drv
->bdrv_attach_aio_context(bs
, new_context
);
7410 assert(!bs
->walking_aio_notifiers
);
7411 bs
->walking_aio_notifiers
= true;
7412 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_tmp
) {
7414 bdrv_do_remove_aio_context_notifier(ban
);
7416 ban
->attached_aio_context(new_context
, ban
->opaque
);
7419 bs
->walking_aio_notifiers
= false;
7422 typedef struct BdrvStateSetAioContext
{
7423 AioContext
*new_ctx
;
7424 BlockDriverState
*bs
;
7425 } BdrvStateSetAioContext
;
7427 static bool bdrv_parent_change_aio_context(BdrvChild
*c
, AioContext
*ctx
,
7428 GHashTable
*visited
,
7432 GLOBAL_STATE_CODE();
7433 if (g_hash_table_contains(visited
, c
)) {
7436 g_hash_table_add(visited
, c
);
7439 * A BdrvChildClass that doesn't handle AioContext changes cannot
7440 * tolerate any AioContext changes
7442 if (!c
->klass
->change_aio_ctx
) {
7443 char *user
= bdrv_child_user_desc(c
);
7444 error_setg(errp
, "Changing iothreads is not supported by %s", user
);
7448 if (!c
->klass
->change_aio_ctx(c
, ctx
, visited
, tran
, errp
)) {
7449 assert(!errp
|| *errp
);
7455 bool bdrv_child_change_aio_context(BdrvChild
*c
, AioContext
*ctx
,
7456 GHashTable
*visited
, Transaction
*tran
,
7459 GLOBAL_STATE_CODE();
7460 if (g_hash_table_contains(visited
, c
)) {
7463 g_hash_table_add(visited
, c
);
7464 return bdrv_change_aio_context(c
->bs
, ctx
, visited
, tran
, errp
);
7467 static void bdrv_set_aio_context_clean(void *opaque
)
7469 BdrvStateSetAioContext
*state
= (BdrvStateSetAioContext
*) opaque
;
7470 BlockDriverState
*bs
= (BlockDriverState
*) state
->bs
;
7472 /* Paired with bdrv_drained_begin in bdrv_change_aio_context() */
7473 bdrv_drained_end(bs
);
7478 static void bdrv_set_aio_context_commit(void *opaque
)
7480 BdrvStateSetAioContext
*state
= (BdrvStateSetAioContext
*) opaque
;
7481 BlockDriverState
*bs
= (BlockDriverState
*) state
->bs
;
7482 AioContext
*new_context
= state
->new_ctx
;
7483 AioContext
*old_context
= bdrv_get_aio_context(bs
);
7486 * Take the old AioContex when detaching it from bs.
7487 * At this point, new_context lock is already acquired, and we are now
7488 * also taking old_context. This is safe as long as bdrv_detach_aio_context
7489 * does not call AIO_POLL_WHILE().
7491 if (old_context
!= qemu_get_aio_context()) {
7492 aio_context_acquire(old_context
);
7494 bdrv_detach_aio_context(bs
);
7495 if (old_context
!= qemu_get_aio_context()) {
7496 aio_context_release(old_context
);
7498 bdrv_attach_aio_context(bs
, new_context
);
7501 static TransactionActionDrv set_aio_context
= {
7502 .commit
= bdrv_set_aio_context_commit
,
7503 .clean
= bdrv_set_aio_context_clean
,
7507 * Changes the AioContext used for fd handlers, timers, and BHs by this
7508 * BlockDriverState and all its children and parents.
7510 * Must be called from the main AioContext.
7512 * The caller must own the AioContext lock for the old AioContext of bs, but it
7513 * must not own the AioContext lock for new_context (unless new_context is the
7514 * same as the current context of bs).
7516 * @visited will accumulate all visited BdrvChild objects. The caller is
7517 * responsible for freeing the list afterwards.
7519 static bool bdrv_change_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
7520 GHashTable
*visited
, Transaction
*tran
,
7524 BdrvStateSetAioContext
*state
;
7526 GLOBAL_STATE_CODE();
7528 if (bdrv_get_aio_context(bs
) == ctx
) {
7532 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
7533 if (!bdrv_parent_change_aio_context(c
, ctx
, visited
, tran
, errp
)) {
7538 QLIST_FOREACH(c
, &bs
->children
, next
) {
7539 if (!bdrv_child_change_aio_context(c
, ctx
, visited
, tran
, errp
)) {
7544 state
= g_new(BdrvStateSetAioContext
, 1);
7545 *state
= (BdrvStateSetAioContext
) {
7550 /* Paired with bdrv_drained_end in bdrv_set_aio_context_clean() */
7551 bdrv_drained_begin(bs
);
7553 tran_add(tran
, &set_aio_context
, state
);
7559 * Change bs's and recursively all of its parents' and children's AioContext
7560 * to the given new context, returning an error if that isn't possible.
7562 * If ignore_child is not NULL, that child (and its subgraph) will not
7565 * This function still requires the caller to take the bs current
7566 * AioContext lock, otherwise draining will fail since AIO_WAIT_WHILE
7567 * assumes the lock is always held if bs is in another AioContext.
7568 * For the same reason, it temporarily also holds the new AioContext, since
7569 * bdrv_drained_end calls BDRV_POLL_WHILE that assumes the lock is taken too.
7570 * Therefore the new AioContext lock must not be taken by the caller.
7572 int bdrv_try_change_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
7573 BdrvChild
*ignore_child
, Error
**errp
)
7576 GHashTable
*visited
;
7578 AioContext
*old_context
= bdrv_get_aio_context(bs
);
7579 GLOBAL_STATE_CODE();
7582 * Recursion phase: go through all nodes of the graph.
7583 * Take care of checking that all nodes support changing AioContext
7584 * and drain them, builing a linear list of callbacks to run if everything
7585 * is successful (the transaction itself).
7588 visited
= g_hash_table_new(NULL
, NULL
);
7590 g_hash_table_add(visited
, ignore_child
);
7592 ret
= bdrv_change_aio_context(bs
, ctx
, visited
, tran
, errp
);
7593 g_hash_table_destroy(visited
);
7596 * Linear phase: go through all callbacks collected in the transaction.
7597 * Run all callbacks collected in the recursion to switch all nodes
7598 * AioContext lock (transaction commit), or undo all changes done in the
7599 * recursion (transaction abort).
7603 /* Just run clean() callbacks. No AioContext changed. */
7609 * Release old AioContext, it won't be needed anymore, as all
7610 * bdrv_drained_begin() have been called already.
7612 if (qemu_get_aio_context() != old_context
) {
7613 aio_context_release(old_context
);
7617 * Acquire new AioContext since bdrv_drained_end() is going to be called
7618 * after we switched all nodes in the new AioContext, and the function
7619 * assumes that the lock of the bs is always taken.
7621 if (qemu_get_aio_context() != ctx
) {
7622 aio_context_acquire(ctx
);
7627 if (qemu_get_aio_context() != ctx
) {
7628 aio_context_release(ctx
);
7631 /* Re-acquire the old AioContext, since the caller takes and releases it. */
7632 if (qemu_get_aio_context() != old_context
) {
7633 aio_context_acquire(old_context
);
7639 void bdrv_add_aio_context_notifier(BlockDriverState
*bs
,
7640 void (*attached_aio_context
)(AioContext
*new_context
, void *opaque
),
7641 void (*detach_aio_context
)(void *opaque
), void *opaque
)
7643 BdrvAioNotifier
*ban
= g_new(BdrvAioNotifier
, 1);
7644 *ban
= (BdrvAioNotifier
){
7645 .attached_aio_context
= attached_aio_context
,
7646 .detach_aio_context
= detach_aio_context
,
7649 GLOBAL_STATE_CODE();
7651 QLIST_INSERT_HEAD(&bs
->aio_notifiers
, ban
, list
);
7654 void bdrv_remove_aio_context_notifier(BlockDriverState
*bs
,
7655 void (*attached_aio_context
)(AioContext
*,
7657 void (*detach_aio_context
)(void *),
7660 BdrvAioNotifier
*ban
, *ban_next
;
7661 GLOBAL_STATE_CODE();
7663 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_next
) {
7664 if (ban
->attached_aio_context
== attached_aio_context
&&
7665 ban
->detach_aio_context
== detach_aio_context
&&
7666 ban
->opaque
== opaque
&&
7667 ban
->deleted
== false)
7669 if (bs
->walking_aio_notifiers
) {
7670 ban
->deleted
= true;
7672 bdrv_do_remove_aio_context_notifier(ban
);
7681 int bdrv_amend_options(BlockDriverState
*bs
, QemuOpts
*opts
,
7682 BlockDriverAmendStatusCB
*status_cb
, void *cb_opaque
,
7686 GLOBAL_STATE_CODE();
7688 error_setg(errp
, "Node is ejected");
7691 if (!bs
->drv
->bdrv_amend_options
) {
7692 error_setg(errp
, "Block driver '%s' does not support option amendment",
7693 bs
->drv
->format_name
);
7696 return bs
->drv
->bdrv_amend_options(bs
, opts
, status_cb
,
7697 cb_opaque
, force
, errp
);
7701 * This function checks whether the given @to_replace is allowed to be
7702 * replaced by a node that always shows the same data as @bs. This is
7703 * used for example to verify whether the mirror job can replace
7704 * @to_replace by the target mirrored from @bs.
7705 * To be replaceable, @bs and @to_replace may either be guaranteed to
7706 * always show the same data (because they are only connected through
7707 * filters), or some driver may allow replacing one of its children
7708 * because it can guarantee that this child's data is not visible at
7709 * all (for example, for dissenting quorum children that have no other
7712 bool bdrv_recurse_can_replace(BlockDriverState
*bs
,
7713 BlockDriverState
*to_replace
)
7715 BlockDriverState
*filtered
;
7717 GLOBAL_STATE_CODE();
7719 if (!bs
|| !bs
->drv
) {
7723 if (bs
== to_replace
) {
7727 /* See what the driver can do */
7728 if (bs
->drv
->bdrv_recurse_can_replace
) {
7729 return bs
->drv
->bdrv_recurse_can_replace(bs
, to_replace
);
7732 /* For filters without an own implementation, we can recurse on our own */
7733 filtered
= bdrv_filter_bs(bs
);
7735 return bdrv_recurse_can_replace(filtered
, to_replace
);
7743 * Check whether the given @node_name can be replaced by a node that
7744 * has the same data as @parent_bs. If so, return @node_name's BDS;
7747 * @node_name must be a (recursive) *child of @parent_bs (or this
7748 * function will return NULL).
7750 * The result (whether the node can be replaced or not) is only valid
7751 * for as long as no graph or permission changes occur.
7753 BlockDriverState
*check_to_replace_node(BlockDriverState
*parent_bs
,
7754 const char *node_name
, Error
**errp
)
7756 BlockDriverState
*to_replace_bs
= bdrv_find_node(node_name
);
7757 AioContext
*aio_context
;
7759 GLOBAL_STATE_CODE();
7761 if (!to_replace_bs
) {
7762 error_setg(errp
, "Failed to find node with node-name='%s'", node_name
);
7766 aio_context
= bdrv_get_aio_context(to_replace_bs
);
7767 aio_context_acquire(aio_context
);
7769 if (bdrv_op_is_blocked(to_replace_bs
, BLOCK_OP_TYPE_REPLACE
, errp
)) {
7770 to_replace_bs
= NULL
;
7774 /* We don't want arbitrary node of the BDS chain to be replaced only the top
7775 * most non filter in order to prevent data corruption.
7776 * Another benefit is that this tests exclude backing files which are
7777 * blocked by the backing blockers.
7779 if (!bdrv_recurse_can_replace(parent_bs
, to_replace_bs
)) {
7780 error_setg(errp
, "Cannot replace '%s' by a node mirrored from '%s', "
7781 "because it cannot be guaranteed that doing so would not "
7782 "lead to an abrupt change of visible data",
7783 node_name
, parent_bs
->node_name
);
7784 to_replace_bs
= NULL
;
7789 aio_context_release(aio_context
);
7790 return to_replace_bs
;
7794 * Iterates through the list of runtime option keys that are said to
7795 * be "strong" for a BDS. An option is called "strong" if it changes
7796 * a BDS's data. For example, the null block driver's "size" and
7797 * "read-zeroes" options are strong, but its "latency-ns" option is
7800 * If a key returned by this function ends with a dot, all options
7801 * starting with that prefix are strong.
7803 static const char *const *strong_options(BlockDriverState
*bs
,
7804 const char *const *curopt
)
7806 static const char *const global_options
[] = {
7807 "driver", "filename", NULL
7811 return &global_options
[0];
7815 if (curopt
== &global_options
[ARRAY_SIZE(global_options
) - 1] && bs
->drv
) {
7816 curopt
= bs
->drv
->strong_runtime_opts
;
7819 return (curopt
&& *curopt
) ? curopt
: NULL
;
7823 * Copies all strong runtime options from bs->options to the given
7824 * QDict. The set of strong option keys is determined by invoking
7827 * Returns true iff any strong option was present in bs->options (and
7828 * thus copied to the target QDict) with the exception of "filename"
7829 * and "driver". The caller is expected to use this value to decide
7830 * whether the existence of strong options prevents the generation of
7833 static bool append_strong_runtime_options(QDict
*d
, BlockDriverState
*bs
)
7835 bool found_any
= false;
7836 const char *const *option_name
= NULL
;
7842 while ((option_name
= strong_options(bs
, option_name
))) {
7843 bool option_given
= false;
7845 assert(strlen(*option_name
) > 0);
7846 if ((*option_name
)[strlen(*option_name
) - 1] != '.') {
7847 QObject
*entry
= qdict_get(bs
->options
, *option_name
);
7852 qdict_put_obj(d
, *option_name
, qobject_ref(entry
));
7853 option_given
= true;
7855 const QDictEntry
*entry
;
7856 for (entry
= qdict_first(bs
->options
); entry
;
7857 entry
= qdict_next(bs
->options
, entry
))
7859 if (strstart(qdict_entry_key(entry
), *option_name
, NULL
)) {
7860 qdict_put_obj(d
, qdict_entry_key(entry
),
7861 qobject_ref(qdict_entry_value(entry
)));
7862 option_given
= true;
7867 /* While "driver" and "filename" need to be included in a JSON filename,
7868 * their existence does not prohibit generation of a plain filename. */
7869 if (!found_any
&& option_given
&&
7870 strcmp(*option_name
, "driver") && strcmp(*option_name
, "filename"))
7876 if (!qdict_haskey(d
, "driver")) {
7877 /* Drivers created with bdrv_new_open_driver() may not have a
7878 * @driver option. Add it here. */
7879 qdict_put_str(d
, "driver", bs
->drv
->format_name
);
7885 /* Note: This function may return false positives; it may return true
7886 * even if opening the backing file specified by bs's image header
7887 * would result in exactly bs->backing. */
7888 static bool bdrv_backing_overridden(BlockDriverState
*bs
)
7890 GLOBAL_STATE_CODE();
7892 return strcmp(bs
->auto_backing_file
,
7893 bs
->backing
->bs
->filename
);
7895 /* No backing BDS, so if the image header reports any backing
7896 * file, it must have been suppressed */
7897 return bs
->auto_backing_file
[0] != '\0';
7901 /* Updates the following BDS fields:
7902 * - exact_filename: A filename which may be used for opening a block device
7903 * which (mostly) equals the given BDS (even without any
7904 * other options; so reading and writing must return the same
7905 * results, but caching etc. may be different)
7906 * - full_open_options: Options which, when given when opening a block device
7907 * (without a filename), result in a BDS (mostly)
7908 * equalling the given one
7909 * - filename: If exact_filename is set, it is copied here. Otherwise,
7910 * full_open_options is converted to a JSON object, prefixed with
7911 * "json:" (for use through the JSON pseudo protocol) and put here.
7913 void bdrv_refresh_filename(BlockDriverState
*bs
)
7915 BlockDriver
*drv
= bs
->drv
;
7917 BlockDriverState
*primary_child_bs
;
7919 bool backing_overridden
;
7920 bool generate_json_filename
; /* Whether our default implementation should
7921 fill exact_filename (false) or not (true) */
7923 GLOBAL_STATE_CODE();
7929 /* This BDS's file name may depend on any of its children's file names, so
7930 * refresh those first */
7931 QLIST_FOREACH(child
, &bs
->children
, next
) {
7932 bdrv_refresh_filename(child
->bs
);
7936 /* For implicit nodes, just copy everything from the single child */
7937 child
= QLIST_FIRST(&bs
->children
);
7938 assert(QLIST_NEXT(child
, next
) == NULL
);
7940 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
),
7941 child
->bs
->exact_filename
);
7942 pstrcpy(bs
->filename
, sizeof(bs
->filename
), child
->bs
->filename
);
7944 qobject_unref(bs
->full_open_options
);
7945 bs
->full_open_options
= qobject_ref(child
->bs
->full_open_options
);
7950 backing_overridden
= bdrv_backing_overridden(bs
);
7952 if (bs
->open_flags
& BDRV_O_NO_IO
) {
7953 /* Without I/O, the backing file does not change anything.
7954 * Therefore, in such a case (primarily qemu-img), we can
7955 * pretend the backing file has not been overridden even if
7956 * it technically has been. */
7957 backing_overridden
= false;
7960 /* Gather the options QDict */
7962 generate_json_filename
= append_strong_runtime_options(opts
, bs
);
7963 generate_json_filename
|= backing_overridden
;
7965 if (drv
->bdrv_gather_child_options
) {
7966 /* Some block drivers may not want to present all of their children's
7967 * options, or name them differently from BdrvChild.name */
7968 drv
->bdrv_gather_child_options(bs
, opts
, backing_overridden
);
7970 QLIST_FOREACH(child
, &bs
->children
, next
) {
7971 if (child
== bs
->backing
&& !backing_overridden
) {
7972 /* We can skip the backing BDS if it has not been overridden */
7976 qdict_put(opts
, child
->name
,
7977 qobject_ref(child
->bs
->full_open_options
));
7980 if (backing_overridden
&& !bs
->backing
) {
7981 /* Force no backing file */
7982 qdict_put_null(opts
, "backing");
7986 qobject_unref(bs
->full_open_options
);
7987 bs
->full_open_options
= opts
;
7989 primary_child_bs
= bdrv_primary_bs(bs
);
7991 if (drv
->bdrv_refresh_filename
) {
7992 /* Obsolete information is of no use here, so drop the old file name
7993 * information before refreshing it */
7994 bs
->exact_filename
[0] = '\0';
7996 drv
->bdrv_refresh_filename(bs
);
7997 } else if (primary_child_bs
) {
7999 * Try to reconstruct valid information from the underlying
8000 * file -- this only works for format nodes (filter nodes
8001 * cannot be probed and as such must be selected by the user
8002 * either through an options dict, or through a special
8003 * filename which the filter driver must construct in its
8004 * .bdrv_refresh_filename() implementation).
8007 bs
->exact_filename
[0] = '\0';
8010 * We can use the underlying file's filename if:
8011 * - it has a filename,
8012 * - the current BDS is not a filter,
8013 * - the file is a protocol BDS, and
8014 * - opening that file (as this BDS's format) will automatically create
8015 * the BDS tree we have right now, that is:
8016 * - the user did not significantly change this BDS's behavior with
8017 * some explicit (strong) options
8018 * - no non-file child of this BDS has been overridden by the user
8019 * Both of these conditions are represented by generate_json_filename.
8021 if (primary_child_bs
->exact_filename
[0] &&
8022 primary_child_bs
->drv
->bdrv_file_open
&&
8023 !drv
->is_filter
&& !generate_json_filename
)
8025 strcpy(bs
->exact_filename
, primary_child_bs
->exact_filename
);
8029 if (bs
->exact_filename
[0]) {
8030 pstrcpy(bs
->filename
, sizeof(bs
->filename
), bs
->exact_filename
);
8032 GString
*json
= qobject_to_json(QOBJECT(bs
->full_open_options
));
8033 if (snprintf(bs
->filename
, sizeof(bs
->filename
), "json:%s",
8034 json
->str
) >= sizeof(bs
->filename
)) {
8035 /* Give user a hint if we truncated things. */
8036 strcpy(bs
->filename
+ sizeof(bs
->filename
) - 4, "...");
8038 g_string_free(json
, true);
8042 char *bdrv_dirname(BlockDriverState
*bs
, Error
**errp
)
8044 BlockDriver
*drv
= bs
->drv
;
8045 BlockDriverState
*child_bs
;
8047 GLOBAL_STATE_CODE();
8050 error_setg(errp
, "Node '%s' is ejected", bs
->node_name
);
8054 if (drv
->bdrv_dirname
) {
8055 return drv
->bdrv_dirname(bs
, errp
);
8058 child_bs
= bdrv_primary_bs(bs
);
8060 return bdrv_dirname(child_bs
, errp
);
8063 bdrv_refresh_filename(bs
);
8064 if (bs
->exact_filename
[0] != '\0') {
8065 return path_combine(bs
->exact_filename
, "");
8068 error_setg(errp
, "Cannot generate a base directory for %s nodes",
8074 * Hot add/remove a BDS's child. So the user can take a child offline when
8075 * it is broken and take a new child online
8077 void bdrv_add_child(BlockDriverState
*parent_bs
, BlockDriverState
*child_bs
,
8080 GLOBAL_STATE_CODE();
8081 if (!parent_bs
->drv
|| !parent_bs
->drv
->bdrv_add_child
) {
8082 error_setg(errp
, "The node %s does not support adding a child",
8083 bdrv_get_device_or_node_name(parent_bs
));
8088 * Non-zoned block drivers do not follow zoned storage constraints
8089 * (i.e. sequential writes to zones). Refuse mixing zoned and non-zoned
8090 * drivers in a graph.
8092 if (!parent_bs
->drv
->supports_zoned_children
&&
8093 child_bs
->bl
.zoned
== BLK_Z_HM
) {
8095 * The host-aware model allows zoned storage constraints and random
8096 * write. Allow mixing host-aware and non-zoned drivers. Using
8097 * host-aware device as a regular device.
8099 error_setg(errp
, "Cannot add a %s child to a %s parent",
8100 child_bs
->bl
.zoned
== BLK_Z_HM
? "zoned" : "non-zoned",
8101 parent_bs
->drv
->supports_zoned_children
?
8102 "support zoned children" : "not support zoned children");
8106 if (!QLIST_EMPTY(&child_bs
->parents
)) {
8107 error_setg(errp
, "The node %s already has a parent",
8108 child_bs
->node_name
);
8112 parent_bs
->drv
->bdrv_add_child(parent_bs
, child_bs
, errp
);
8115 void bdrv_del_child(BlockDriverState
*parent_bs
, BdrvChild
*child
, Error
**errp
)
8119 GLOBAL_STATE_CODE();
8120 if (!parent_bs
->drv
|| !parent_bs
->drv
->bdrv_del_child
) {
8121 error_setg(errp
, "The node %s does not support removing a child",
8122 bdrv_get_device_or_node_name(parent_bs
));
8126 QLIST_FOREACH(tmp
, &parent_bs
->children
, next
) {
8133 error_setg(errp
, "The node %s does not have a child named %s",
8134 bdrv_get_device_or_node_name(parent_bs
),
8135 bdrv_get_device_or_node_name(child
->bs
));
8139 parent_bs
->drv
->bdrv_del_child(parent_bs
, child
, errp
);
8142 int bdrv_make_empty(BdrvChild
*c
, Error
**errp
)
8144 BlockDriver
*drv
= c
->bs
->drv
;
8147 GLOBAL_STATE_CODE();
8148 assert(c
->perm
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
));
8150 if (!drv
->bdrv_make_empty
) {
8151 error_setg(errp
, "%s does not support emptying nodes",
8156 ret
= drv
->bdrv_make_empty(c
->bs
);
8158 error_setg_errno(errp
, -ret
, "Failed to empty %s",
8167 * Return the child that @bs acts as an overlay for, and from which data may be
8168 * copied in COW or COR operations. Usually this is the backing file.
8170 BdrvChild
*bdrv_cow_child(BlockDriverState
*bs
)
8174 if (!bs
|| !bs
->drv
) {
8178 if (bs
->drv
->is_filter
) {
8186 assert(bs
->backing
->role
& BDRV_CHILD_COW
);
8191 * If @bs acts as a filter for exactly one of its children, return
8194 BdrvChild
*bdrv_filter_child(BlockDriverState
*bs
)
8199 if (!bs
|| !bs
->drv
) {
8203 if (!bs
->drv
->is_filter
) {
8207 /* Only one of @backing or @file may be used */
8208 assert(!(bs
->backing
&& bs
->file
));
8210 c
= bs
->backing
?: bs
->file
;
8215 assert(c
->role
& BDRV_CHILD_FILTERED
);
8220 * Return either the result of bdrv_cow_child() or bdrv_filter_child(),
8221 * whichever is non-NULL.
8223 * Return NULL if both are NULL.
8225 BdrvChild
*bdrv_filter_or_cow_child(BlockDriverState
*bs
)
8227 BdrvChild
*cow_child
= bdrv_cow_child(bs
);
8228 BdrvChild
*filter_child
= bdrv_filter_child(bs
);
8231 /* Filter nodes cannot have COW backing files */
8232 assert(!(cow_child
&& filter_child
));
8234 return cow_child
?: filter_child
;
8238 * Return the primary child of this node: For filters, that is the
8239 * filtered child. For other nodes, that is usually the child storing
8241 * (A generally more helpful description is that this is (usually) the
8242 * child that has the same filename as @bs.)
8244 * Drivers do not necessarily have a primary child; for example quorum
8247 BdrvChild
*bdrv_primary_child(BlockDriverState
*bs
)
8249 BdrvChild
*c
, *found
= NULL
;
8252 QLIST_FOREACH(c
, &bs
->children
, next
) {
8253 if (c
->role
& BDRV_CHILD_PRIMARY
) {
8262 static BlockDriverState
*bdrv_do_skip_filters(BlockDriverState
*bs
,
8263 bool stop_on_explicit_filter
)
8271 while (!(stop_on_explicit_filter
&& !bs
->implicit
)) {
8272 c
= bdrv_filter_child(bs
);
8275 * A filter that is embedded in a working block graph must
8276 * have a child. Assert this here so this function does
8277 * not return a filter node that is not expected by the
8280 assert(!bs
->drv
|| !bs
->drv
->is_filter
);
8286 * Note that this treats nodes with bs->drv == NULL as not being
8287 * filters (bs->drv == NULL should be replaced by something else
8289 * The advantage of this behavior is that this function will thus
8290 * always return a non-NULL value (given a non-NULL @bs).
8297 * Return the first BDS that has not been added implicitly or that
8298 * does not have a filtered child down the chain starting from @bs
8299 * (including @bs itself).
8301 BlockDriverState
*bdrv_skip_implicit_filters(BlockDriverState
*bs
)
8303 GLOBAL_STATE_CODE();
8304 return bdrv_do_skip_filters(bs
, true);
8308 * Return the first BDS that does not have a filtered child down the
8309 * chain starting from @bs (including @bs itself).
8311 BlockDriverState
*bdrv_skip_filters(BlockDriverState
*bs
)
8314 return bdrv_do_skip_filters(bs
, false);
8318 * For a backing chain, return the first non-filter backing image of
8319 * the first non-filter image.
8321 BlockDriverState
*bdrv_backing_chain_next(BlockDriverState
*bs
)
8324 return bdrv_skip_filters(bdrv_cow_bs(bdrv_skip_filters(bs
)));
8328 * Check whether [offset, offset + bytes) overlaps with the cached
8329 * block-status data region.
8331 * If so, and @pnum is not NULL, set *pnum to `bsc.data_end - offset`,
8332 * which is what bdrv_bsc_is_data()'s interface needs.
8333 * Otherwise, *pnum is not touched.
8335 static bool bdrv_bsc_range_overlaps_locked(BlockDriverState
*bs
,
8336 int64_t offset
, int64_t bytes
,
8339 BdrvBlockStatusCache
*bsc
= qatomic_rcu_read(&bs
->block_status_cache
);
8343 qatomic_read(&bsc
->valid
) &&
8344 ranges_overlap(offset
, bytes
, bsc
->data_start
,
8345 bsc
->data_end
- bsc
->data_start
);
8347 if (overlaps
&& pnum
) {
8348 *pnum
= bsc
->data_end
- offset
;
8355 * See block_int.h for this function's documentation.
8357 bool bdrv_bsc_is_data(BlockDriverState
*bs
, int64_t offset
, int64_t *pnum
)
8360 RCU_READ_LOCK_GUARD();
8361 return bdrv_bsc_range_overlaps_locked(bs
, offset
, 1, pnum
);
8365 * See block_int.h for this function's documentation.
8367 void bdrv_bsc_invalidate_range(BlockDriverState
*bs
,
8368 int64_t offset
, int64_t bytes
)
8371 RCU_READ_LOCK_GUARD();
8373 if (bdrv_bsc_range_overlaps_locked(bs
, offset
, bytes
, NULL
)) {
8374 qatomic_set(&bs
->block_status_cache
->valid
, false);
8379 * See block_int.h for this function's documentation.
8381 void bdrv_bsc_fill(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
)
8383 BdrvBlockStatusCache
*new_bsc
= g_new(BdrvBlockStatusCache
, 1);
8384 BdrvBlockStatusCache
*old_bsc
;
8387 *new_bsc
= (BdrvBlockStatusCache
) {
8389 .data_start
= offset
,
8390 .data_end
= offset
+ bytes
,
8393 QEMU_LOCK_GUARD(&bs
->bsc_modify_lock
);
8395 old_bsc
= qatomic_rcu_read(&bs
->block_status_cache
);
8396 qatomic_rcu_set(&bs
->block_status_cache
, new_bsc
);
8398 g_free_rcu(old_bsc
, rcu
);