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 GRAPH_WRLOCK
95 bdrv_replace_child_noperm(BdrvChild
*child
, BlockDriverState
*new_bs
);
97 static void bdrv_remove_child(BdrvChild
*child
, Transaction
*tran
);
99 static int bdrv_reopen_prepare(BDRVReopenState
*reopen_state
,
100 BlockReopenQueue
*queue
,
101 Transaction
*change_child_tran
, Error
**errp
);
102 static void bdrv_reopen_commit(BDRVReopenState
*reopen_state
);
103 static void bdrv_reopen_abort(BDRVReopenState
*reopen_state
);
105 static bool bdrv_backing_overridden(BlockDriverState
*bs
);
107 static bool bdrv_change_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
108 GHashTable
*visited
, Transaction
*tran
,
111 /* If non-zero, use only whitelisted block drivers */
112 static int use_bdrv_whitelist
;
115 static int is_windows_drive_prefix(const char *filename
)
117 return (((filename
[0] >= 'a' && filename
[0] <= 'z') ||
118 (filename
[0] >= 'A' && filename
[0] <= 'Z')) &&
122 int is_windows_drive(const char *filename
)
124 if (is_windows_drive_prefix(filename
) &&
127 if (strstart(filename
, "\\\\.\\", NULL
) ||
128 strstart(filename
, "//./", NULL
))
134 size_t bdrv_opt_mem_align(BlockDriverState
*bs
)
136 if (!bs
|| !bs
->drv
) {
137 /* page size or 4k (hdd sector size) should be on the safe side */
138 return MAX(4096, qemu_real_host_page_size());
142 return bs
->bl
.opt_mem_alignment
;
145 size_t bdrv_min_mem_align(BlockDriverState
*bs
)
147 if (!bs
|| !bs
->drv
) {
148 /* page size or 4k (hdd sector size) should be on the safe side */
149 return MAX(4096, qemu_real_host_page_size());
153 return bs
->bl
.min_mem_alignment
;
156 /* check if the path starts with "<protocol>:" */
157 int path_has_protocol(const char *path
)
162 if (is_windows_drive(path
) ||
163 is_windows_drive_prefix(path
)) {
166 p
= path
+ strcspn(path
, ":/\\");
168 p
= path
+ strcspn(path
, ":/");
174 int path_is_absolute(const char *path
)
177 /* specific case for names like: "\\.\d:" */
178 if (is_windows_drive(path
) || is_windows_drive_prefix(path
)) {
181 return (*path
== '/' || *path
== '\\');
183 return (*path
== '/');
187 /* if filename is absolute, just return its duplicate. Otherwise, build a
188 path to it by considering it is relative to base_path. URL are
190 char *path_combine(const char *base_path
, const char *filename
)
192 const char *protocol_stripped
= NULL
;
197 if (path_is_absolute(filename
)) {
198 return g_strdup(filename
);
201 if (path_has_protocol(base_path
)) {
202 protocol_stripped
= strchr(base_path
, ':');
203 if (protocol_stripped
) {
207 p
= protocol_stripped
?: base_path
;
209 p1
= strrchr(base_path
, '/');
213 p2
= strrchr(base_path
, '\\');
214 if (!p1
|| p2
> p1
) {
229 result
= g_malloc(len
+ strlen(filename
) + 1);
230 memcpy(result
, base_path
, len
);
231 strcpy(result
+ len
, filename
);
237 * Helper function for bdrv_parse_filename() implementations to remove optional
238 * protocol prefixes (especially "file:") from a filename and for putting the
239 * stripped filename into the options QDict if there is such a prefix.
241 void bdrv_parse_filename_strip_prefix(const char *filename
, const char *prefix
,
244 if (strstart(filename
, prefix
, &filename
)) {
245 /* Stripping the explicit protocol prefix may result in a protocol
246 * prefix being (wrongly) detected (if the filename contains a colon) */
247 if (path_has_protocol(filename
)) {
248 GString
*fat_filename
;
250 /* This means there is some colon before the first slash; therefore,
251 * this cannot be an absolute path */
252 assert(!path_is_absolute(filename
));
254 /* And we can thus fix the protocol detection issue by prefixing it
256 fat_filename
= g_string_new("./");
257 g_string_append(fat_filename
, filename
);
259 assert(!path_has_protocol(fat_filename
->str
));
261 qdict_put(options
, "filename",
262 qstring_from_gstring(fat_filename
));
264 /* If no protocol prefix was detected, we can use the shortened
266 qdict_put_str(options
, "filename", filename
);
272 /* Returns whether the image file is opened as read-only. Note that this can
273 * return false and writing to the image file is still not possible because the
274 * image is inactivated. */
275 bool bdrv_is_read_only(BlockDriverState
*bs
)
278 return !(bs
->open_flags
& BDRV_O_RDWR
);
281 static int bdrv_can_set_read_only(BlockDriverState
*bs
, bool read_only
,
282 bool ignore_allow_rdw
, Error
**errp
)
286 /* Do not set read_only if copy_on_read is enabled */
287 if (bs
->copy_on_read
&& read_only
) {
288 error_setg(errp
, "Can't set node '%s' to r/o with copy-on-read enabled",
289 bdrv_get_device_or_node_name(bs
));
293 /* Do not clear read_only if it is prohibited */
294 if (!read_only
&& !(bs
->open_flags
& BDRV_O_ALLOW_RDWR
) &&
297 error_setg(errp
, "Node '%s' is read only",
298 bdrv_get_device_or_node_name(bs
));
306 * Called by a driver that can only provide a read-only image.
308 * Returns 0 if the node is already read-only or it could switch the node to
309 * read-only because BDRV_O_AUTO_RDONLY is set.
311 * Returns -EACCES if the node is read-write and BDRV_O_AUTO_RDONLY is not set
312 * or bdrv_can_set_read_only() forbids making the node read-only. If @errmsg
313 * is not NULL, it is used as the error message for the Error object.
315 int bdrv_apply_auto_read_only(BlockDriverState
*bs
, const char *errmsg
,
321 if (!(bs
->open_flags
& BDRV_O_RDWR
)) {
324 if (!(bs
->open_flags
& BDRV_O_AUTO_RDONLY
)) {
328 ret
= bdrv_can_set_read_only(bs
, true, false, NULL
);
333 bs
->open_flags
&= ~BDRV_O_RDWR
;
338 error_setg(errp
, "%s", errmsg
?: "Image is read-only");
343 * If @backing is empty, this function returns NULL without setting
344 * @errp. In all other cases, NULL will only be returned with @errp
347 * Therefore, a return value of NULL without @errp set means that
348 * there is no backing file; if @errp is set, there is one but its
349 * absolute filename cannot be generated.
351 char *bdrv_get_full_backing_filename_from_filename(const char *backed
,
355 if (backing
[0] == '\0') {
357 } else if (path_has_protocol(backing
) || path_is_absolute(backing
)) {
358 return g_strdup(backing
);
359 } else if (backed
[0] == '\0' || strstart(backed
, "json:", NULL
)) {
360 error_setg(errp
, "Cannot use relative backing file names for '%s'",
364 return path_combine(backed
, backing
);
369 * If @filename is empty or NULL, this function returns NULL without
370 * setting @errp. In all other cases, NULL will only be returned with
373 static char *bdrv_make_absolute_filename(BlockDriverState
*relative_to
,
374 const char *filename
, Error
**errp
)
376 char *dir
, *full_name
;
378 if (!filename
|| filename
[0] == '\0') {
380 } else if (path_has_protocol(filename
) || path_is_absolute(filename
)) {
381 return g_strdup(filename
);
384 dir
= bdrv_dirname(relative_to
, errp
);
389 full_name
= g_strconcat(dir
, filename
, NULL
);
394 char *bdrv_get_full_backing_filename(BlockDriverState
*bs
, Error
**errp
)
397 return bdrv_make_absolute_filename(bs
, bs
->backing_file
, errp
);
400 void bdrv_register(BlockDriver
*bdrv
)
402 assert(bdrv
->format_name
);
404 QLIST_INSERT_HEAD(&bdrv_drivers
, bdrv
, list
);
407 BlockDriverState
*bdrv_new(void)
409 BlockDriverState
*bs
;
414 bs
= g_new0(BlockDriverState
, 1);
415 QLIST_INIT(&bs
->dirty_bitmaps
);
416 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
417 QLIST_INIT(&bs
->op_blockers
[i
]);
419 qemu_mutex_init(&bs
->reqs_lock
);
420 qemu_mutex_init(&bs
->dirty_bitmap_mutex
);
422 bs
->aio_context
= qemu_get_aio_context();
424 qemu_co_queue_init(&bs
->flush_queue
);
426 qemu_co_mutex_init(&bs
->bsc_modify_lock
);
427 bs
->block_status_cache
= g_new0(BdrvBlockStatusCache
, 1);
429 for (i
= 0; i
< bdrv_drain_all_count
; i
++) {
430 bdrv_drained_begin(bs
);
433 QTAILQ_INSERT_TAIL(&all_bdrv_states
, bs
, bs_list
);
438 static BlockDriver
*bdrv_do_find_format(const char *format_name
)
443 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
444 if (!strcmp(drv1
->format_name
, format_name
)) {
452 BlockDriver
*bdrv_find_format(const char *format_name
)
459 drv1
= bdrv_do_find_format(format_name
);
464 /* The driver isn't registered, maybe we need to load a module */
465 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
466 if (!strcmp(block_driver_modules
[i
].format_name
, format_name
)) {
467 Error
*local_err
= NULL
;
468 int rv
= block_module_load(block_driver_modules
[i
].library_name
,
471 return bdrv_do_find_format(format_name
);
473 error_report_err(local_err
);
481 static int bdrv_format_is_whitelisted(const char *format_name
, bool read_only
)
483 static const char *whitelist_rw
[] = {
484 CONFIG_BDRV_RW_WHITELIST
487 static const char *whitelist_ro
[] = {
488 CONFIG_BDRV_RO_WHITELIST
493 if (!whitelist_rw
[0] && !whitelist_ro
[0]) {
494 return 1; /* no whitelist, anything goes */
497 for (p
= whitelist_rw
; *p
; p
++) {
498 if (!strcmp(format_name
, *p
)) {
503 for (p
= whitelist_ro
; *p
; p
++) {
504 if (!strcmp(format_name
, *p
)) {
512 int bdrv_is_whitelisted(BlockDriver
*drv
, bool read_only
)
515 return bdrv_format_is_whitelisted(drv
->format_name
, read_only
);
518 bool bdrv_uses_whitelist(void)
520 return use_bdrv_whitelist
;
523 typedef struct CreateCo
{
531 int coroutine_fn
bdrv_co_create(BlockDriver
*drv
, const char *filename
,
532 QemuOpts
*opts
, Error
**errp
)
538 if (!drv
->bdrv_co_create_opts
) {
539 error_setg(errp
, "Driver '%s' does not support image creation",
544 ret
= drv
->bdrv_co_create_opts(drv
, filename
, opts
, errp
);
545 if (ret
< 0 && !*errp
) {
546 error_setg_errno(errp
, -ret
, "Could not create image");
553 * Helper function for bdrv_create_file_fallback(): Resize @blk to at
554 * least the given @minimum_size.
556 * On success, return @blk's actual length.
557 * Otherwise, return -errno.
559 static int64_t coroutine_fn GRAPH_UNLOCKED
560 create_file_fallback_truncate(BlockBackend
*blk
, int64_t minimum_size
,
563 Error
*local_err
= NULL
;
569 ret
= blk_co_truncate(blk
, minimum_size
, false, PREALLOC_MODE_OFF
, 0,
571 if (ret
< 0 && ret
!= -ENOTSUP
) {
572 error_propagate(errp
, local_err
);
576 size
= blk_co_getlength(blk
);
578 error_free(local_err
);
579 error_setg_errno(errp
, -size
,
580 "Failed to inquire the new image file's length");
584 if (size
< minimum_size
) {
585 /* Need to grow the image, but we failed to do that */
586 error_propagate(errp
, local_err
);
590 error_free(local_err
);
597 * Helper function for bdrv_create_file_fallback(): Zero the first
598 * sector to remove any potentially pre-existing image header.
600 static int coroutine_fn
601 create_file_fallback_zero_first_sector(BlockBackend
*blk
,
602 int64_t current_size
,
605 int64_t bytes_to_clear
;
610 bytes_to_clear
= MIN(current_size
, BDRV_SECTOR_SIZE
);
611 if (bytes_to_clear
) {
612 ret
= blk_co_pwrite_zeroes(blk
, 0, bytes_to_clear
, BDRV_REQ_MAY_UNMAP
);
614 error_setg_errno(errp
, -ret
,
615 "Failed to clear the new image's first sector");
624 * Simple implementation of bdrv_co_create_opts for protocol drivers
625 * which only support creation via opening a file
626 * (usually existing raw storage device)
628 int coroutine_fn
bdrv_co_create_opts_simple(BlockDriver
*drv
,
629 const char *filename
,
637 PreallocMode prealloc
;
638 Error
*local_err
= NULL
;
643 size
= qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0);
644 buf
= qemu_opt_get_del(opts
, BLOCK_OPT_PREALLOC
);
645 prealloc
= qapi_enum_parse(&PreallocMode_lookup
, buf
,
646 PREALLOC_MODE_OFF
, &local_err
);
649 error_propagate(errp
, local_err
);
653 if (prealloc
!= PREALLOC_MODE_OFF
) {
654 error_setg(errp
, "Unsupported preallocation mode '%s'",
655 PreallocMode_str(prealloc
));
659 options
= qdict_new();
660 qdict_put_str(options
, "driver", drv
->format_name
);
662 blk
= blk_co_new_open(filename
, NULL
, options
,
663 BDRV_O_RDWR
| BDRV_O_RESIZE
, errp
);
665 error_prepend(errp
, "Protocol driver '%s' does not support creating "
666 "new images, so an existing image must be selected as "
667 "the target; however, opening the given target as an "
668 "existing image failed: ",
673 size
= create_file_fallback_truncate(blk
, size
, errp
);
679 ret
= create_file_fallback_zero_first_sector(blk
, size
, errp
);
690 int coroutine_fn
bdrv_co_create_file(const char *filename
, QemuOpts
*opts
,
693 QemuOpts
*protocol_opts
;
700 drv
= bdrv_find_protocol(filename
, true, errp
);
705 if (!drv
->create_opts
) {
706 error_setg(errp
, "Driver '%s' does not support image creation",
712 * 'opts' contains a QemuOptsList with a combination of format and protocol
715 * The format properly removes its options, but the default values remain
716 * in 'opts->list'. So if the protocol has options with the same name
717 * (e.g. rbd has 'cluster_size' as qcow2), it will see the default values
718 * of the format, since for overlapping options, the format wins.
720 * To avoid this issue, lets convert QemuOpts to QDict, in this way we take
721 * only the set options, and then convert it back to QemuOpts, using the
722 * create_opts of the protocol. So the new QemuOpts, will contain only the
725 qdict
= qemu_opts_to_qdict(opts
, NULL
);
726 protocol_opts
= qemu_opts_from_qdict(drv
->create_opts
, qdict
, errp
);
727 if (protocol_opts
== NULL
) {
732 ret
= bdrv_co_create(drv
, filename
, protocol_opts
, errp
);
734 qemu_opts_del(protocol_opts
);
735 qobject_unref(qdict
);
739 int coroutine_fn
bdrv_co_delete_file(BlockDriverState
*bs
, Error
**errp
)
741 Error
*local_err
= NULL
;
746 assert_bdrv_graph_readable();
749 error_setg(errp
, "Block node '%s' is not opened", bs
->filename
);
753 if (!bs
->drv
->bdrv_co_delete_file
) {
754 error_setg(errp
, "Driver '%s' does not support image deletion",
755 bs
->drv
->format_name
);
759 ret
= bs
->drv
->bdrv_co_delete_file(bs
, &local_err
);
761 error_propagate(errp
, local_err
);
767 void coroutine_fn
bdrv_co_delete_file_noerr(BlockDriverState
*bs
)
769 Error
*local_err
= NULL
;
777 ret
= bdrv_co_delete_file(bs
, &local_err
);
779 * ENOTSUP will happen if the block driver doesn't support
780 * the 'bdrv_co_delete_file' interface. This is a predictable
781 * scenario and shouldn't be reported back to the user.
783 if (ret
== -ENOTSUP
) {
784 error_free(local_err
);
785 } else if (ret
< 0) {
786 error_report_err(local_err
);
791 * Try to get @bs's logical and physical block size.
792 * On success, store them in @bsz struct and return 0.
793 * On failure return -errno.
794 * @bs must not be empty.
796 int bdrv_probe_blocksizes(BlockDriverState
*bs
, BlockSizes
*bsz
)
798 BlockDriver
*drv
= bs
->drv
;
799 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
802 if (drv
&& drv
->bdrv_probe_blocksizes
) {
803 return drv
->bdrv_probe_blocksizes(bs
, bsz
);
804 } else if (filtered
) {
805 return bdrv_probe_blocksizes(filtered
, bsz
);
812 * Try to get @bs's geometry (cyls, heads, sectors).
813 * On success, store them in @geo struct and return 0.
814 * On failure return -errno.
815 * @bs must not be empty.
817 int bdrv_probe_geometry(BlockDriverState
*bs
, HDGeometry
*geo
)
819 BlockDriver
*drv
= bs
->drv
;
820 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
823 if (drv
&& drv
->bdrv_probe_geometry
) {
824 return drv
->bdrv_probe_geometry(bs
, geo
);
825 } else if (filtered
) {
826 return bdrv_probe_geometry(filtered
, geo
);
833 * Create a uniquely-named empty temporary file.
834 * Return the actual file name used upon success, otherwise NULL.
835 * This string should be freed with g_free() when not needed any longer.
837 * Note: creating a temporary file for the caller to (re)open is
838 * inherently racy. Use g_file_open_tmp() instead whenever practical.
840 char *create_tmp_file(Error
**errp
)
844 g_autofree
char *filename
= NULL
;
846 tmpdir
= g_get_tmp_dir();
849 * See commit 69bef79 ("block: use /var/tmp instead of /tmp for -snapshot")
851 * This function is used to create temporary disk images (like -snapshot),
852 * so the files can become very large. /tmp is often a tmpfs where as
853 * /var/tmp is usually on a disk, so more appropriate for disk images.
855 if (!g_strcmp0(tmpdir
, "/tmp")) {
860 filename
= g_strdup_printf("%s/vl.XXXXXX", tmpdir
);
861 fd
= g_mkstemp(filename
);
863 error_setg_errno(errp
, errno
, "Could not open temporary file '%s'",
869 return g_steal_pointer(&filename
);
873 * Detect host devices. By convention, /dev/cdrom[N] is always
874 * recognized as a host CDROM.
876 static BlockDriver
*find_hdev_driver(const char *filename
)
878 int score_max
= 0, score
;
879 BlockDriver
*drv
= NULL
, *d
;
882 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
883 if (d
->bdrv_probe_device
) {
884 score
= d
->bdrv_probe_device(filename
);
885 if (score
> score_max
) {
895 static BlockDriver
*bdrv_do_find_protocol(const char *protocol
)
900 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
901 if (drv1
->protocol_name
&& !strcmp(drv1
->protocol_name
, protocol
)) {
909 BlockDriver
*bdrv_find_protocol(const char *filename
,
910 bool allow_protocol_prefix
,
920 /* TODO Drivers without bdrv_file_open must be specified explicitly */
923 * XXX(hch): we really should not let host device detection
924 * override an explicit protocol specification, but moving this
925 * later breaks access to device names with colons in them.
926 * Thanks to the brain-dead persistent naming schemes on udev-
927 * based Linux systems those actually are quite common.
929 drv1
= find_hdev_driver(filename
);
934 if (!path_has_protocol(filename
) || !allow_protocol_prefix
) {
938 p
= strchr(filename
, ':');
941 if (len
> sizeof(protocol
) - 1)
942 len
= sizeof(protocol
) - 1;
943 memcpy(protocol
, filename
, len
);
944 protocol
[len
] = '\0';
946 drv1
= bdrv_do_find_protocol(protocol
);
951 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
952 if (block_driver_modules
[i
].protocol_name
&&
953 !strcmp(block_driver_modules
[i
].protocol_name
, protocol
)) {
954 int rv
= block_module_load(block_driver_modules
[i
].library_name
, errp
);
956 drv1
= bdrv_do_find_protocol(protocol
);
965 error_setg(errp
, "Unknown protocol '%s'", protocol
);
971 * Guess image format by probing its contents.
972 * This is not a good idea when your image is raw (CVE-2008-2004), but
973 * we do it anyway for backward compatibility.
975 * @buf contains the image's first @buf_size bytes.
976 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
977 * but can be smaller if the image file is smaller)
978 * @filename is its filename.
980 * For all block drivers, call the bdrv_probe() method to get its
982 * Return the first block driver with the highest probing score.
984 BlockDriver
*bdrv_probe_all(const uint8_t *buf
, int buf_size
,
985 const char *filename
)
987 int score_max
= 0, score
;
988 BlockDriver
*drv
= NULL
, *d
;
991 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
993 score
= d
->bdrv_probe(buf
, buf_size
, filename
);
994 if (score
> score_max
) {
1004 static int find_image_format(BlockBackend
*file
, const char *filename
,
1005 BlockDriver
**pdrv
, Error
**errp
)
1008 uint8_t buf
[BLOCK_PROBE_BUF_SIZE
];
1011 GLOBAL_STATE_CODE();
1013 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
1014 if (blk_is_sg(file
) || !blk_is_inserted(file
) || blk_getlength(file
) == 0) {
1019 ret
= blk_pread(file
, 0, sizeof(buf
), buf
, 0);
1021 error_setg_errno(errp
, -ret
, "Could not read image for determining its "
1027 drv
= bdrv_probe_all(buf
, sizeof(buf
), filename
);
1029 error_setg(errp
, "Could not determine image format: No compatible "
1040 * Set the current 'total_sectors' value
1041 * Return 0 on success, -errno on error.
1043 int coroutine_fn
bdrv_co_refresh_total_sectors(BlockDriverState
*bs
,
1046 BlockDriver
*drv
= bs
->drv
;
1048 assert_bdrv_graph_readable();
1054 /* Do not attempt drv->bdrv_co_getlength() on scsi-generic devices */
1058 /* query actual device if possible, otherwise just trust the hint */
1059 if (drv
->bdrv_co_getlength
) {
1060 int64_t length
= drv
->bdrv_co_getlength(bs
);
1064 hint
= DIV_ROUND_UP(length
, BDRV_SECTOR_SIZE
);
1067 bs
->total_sectors
= hint
;
1069 if (bs
->total_sectors
* BDRV_SECTOR_SIZE
> BDRV_MAX_LENGTH
) {
1077 * Combines a QDict of new block driver @options with any missing options taken
1078 * from @old_options, so that leaving out an option defaults to its old value.
1080 static void bdrv_join_options(BlockDriverState
*bs
, QDict
*options
,
1083 GLOBAL_STATE_CODE();
1084 if (bs
->drv
&& bs
->drv
->bdrv_join_options
) {
1085 bs
->drv
->bdrv_join_options(options
, old_options
);
1087 qdict_join(options
, old_options
, false);
1091 static BlockdevDetectZeroesOptions
bdrv_parse_detect_zeroes(QemuOpts
*opts
,
1095 Error
*local_err
= NULL
;
1096 char *value
= qemu_opt_get_del(opts
, "detect-zeroes");
1097 BlockdevDetectZeroesOptions detect_zeroes
=
1098 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup
, value
,
1099 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF
, &local_err
);
1100 GLOBAL_STATE_CODE();
1103 error_propagate(errp
, local_err
);
1104 return detect_zeroes
;
1107 if (detect_zeroes
== BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP
&&
1108 !(open_flags
& BDRV_O_UNMAP
))
1110 error_setg(errp
, "setting detect-zeroes to unmap is not allowed "
1111 "without setting discard operation to unmap");
1114 return detect_zeroes
;
1118 * Set open flags for aio engine
1120 * Return 0 on success, -1 if the engine specified is invalid
1122 int bdrv_parse_aio(const char *mode
, int *flags
)
1124 if (!strcmp(mode
, "threads")) {
1125 /* do nothing, default */
1126 } else if (!strcmp(mode
, "native")) {
1127 *flags
|= BDRV_O_NATIVE_AIO
;
1128 #ifdef CONFIG_LINUX_IO_URING
1129 } else if (!strcmp(mode
, "io_uring")) {
1130 *flags
|= BDRV_O_IO_URING
;
1140 * Set open flags for a given discard mode
1142 * Return 0 on success, -1 if the discard mode was invalid.
1144 int bdrv_parse_discard_flags(const char *mode
, int *flags
)
1146 *flags
&= ~BDRV_O_UNMAP
;
1148 if (!strcmp(mode
, "off") || !strcmp(mode
, "ignore")) {
1150 } else if (!strcmp(mode
, "on") || !strcmp(mode
, "unmap")) {
1151 *flags
|= BDRV_O_UNMAP
;
1160 * Set open flags for a given cache mode
1162 * Return 0 on success, -1 if the cache mode was invalid.
1164 int bdrv_parse_cache_mode(const char *mode
, int *flags
, bool *writethrough
)
1166 *flags
&= ~BDRV_O_CACHE_MASK
;
1168 if (!strcmp(mode
, "off") || !strcmp(mode
, "none")) {
1169 *writethrough
= false;
1170 *flags
|= BDRV_O_NOCACHE
;
1171 } else if (!strcmp(mode
, "directsync")) {
1172 *writethrough
= true;
1173 *flags
|= BDRV_O_NOCACHE
;
1174 } else if (!strcmp(mode
, "writeback")) {
1175 *writethrough
= false;
1176 } else if (!strcmp(mode
, "unsafe")) {
1177 *writethrough
= false;
1178 *flags
|= BDRV_O_NO_FLUSH
;
1179 } else if (!strcmp(mode
, "writethrough")) {
1180 *writethrough
= true;
1188 static char *bdrv_child_get_parent_desc(BdrvChild
*c
)
1190 BlockDriverState
*parent
= c
->opaque
;
1191 return g_strdup_printf("node '%s'", bdrv_get_node_name(parent
));
1194 static void bdrv_child_cb_drained_begin(BdrvChild
*child
)
1196 BlockDriverState
*bs
= child
->opaque
;
1197 bdrv_do_drained_begin_quiesce(bs
, NULL
);
1200 static bool bdrv_child_cb_drained_poll(BdrvChild
*child
)
1202 BlockDriverState
*bs
= child
->opaque
;
1203 return bdrv_drain_poll(bs
, NULL
, false);
1206 static void bdrv_child_cb_drained_end(BdrvChild
*child
)
1208 BlockDriverState
*bs
= child
->opaque
;
1209 bdrv_drained_end(bs
);
1212 static int bdrv_child_cb_inactivate(BdrvChild
*child
)
1214 BlockDriverState
*bs
= child
->opaque
;
1215 GLOBAL_STATE_CODE();
1216 assert(bs
->open_flags
& BDRV_O_INACTIVE
);
1220 static bool bdrv_child_cb_change_aio_ctx(BdrvChild
*child
, AioContext
*ctx
,
1221 GHashTable
*visited
, Transaction
*tran
,
1224 BlockDriverState
*bs
= child
->opaque
;
1225 return bdrv_change_aio_context(bs
, ctx
, visited
, tran
, errp
);
1229 * Returns the options and flags that a temporary snapshot should get, based on
1230 * the originally requested flags (the originally requested image will have
1231 * flags like a backing file)
1233 static void bdrv_temp_snapshot_options(int *child_flags
, QDict
*child_options
,
1234 int parent_flags
, QDict
*parent_options
)
1236 GLOBAL_STATE_CODE();
1237 *child_flags
= (parent_flags
& ~BDRV_O_SNAPSHOT
) | BDRV_O_TEMPORARY
;
1239 /* For temporary files, unconditional cache=unsafe is fine */
1240 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_DIRECT
, "off");
1241 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_NO_FLUSH
, "on");
1243 /* Copy the read-only and discard options from the parent */
1244 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1245 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_DISCARD
);
1247 /* aio=native doesn't work for cache.direct=off, so disable it for the
1248 * temporary snapshot */
1249 *child_flags
&= ~BDRV_O_NATIVE_AIO
;
1252 static void bdrv_backing_attach(BdrvChild
*c
)
1254 BlockDriverState
*parent
= c
->opaque
;
1255 BlockDriverState
*backing_hd
= c
->bs
;
1257 GLOBAL_STATE_CODE();
1258 assert(!parent
->backing_blocker
);
1259 error_setg(&parent
->backing_blocker
,
1260 "node is used as backing hd of '%s'",
1261 bdrv_get_device_or_node_name(parent
));
1263 bdrv_refresh_filename(backing_hd
);
1265 parent
->open_flags
&= ~BDRV_O_NO_BACKING
;
1267 bdrv_op_block_all(backing_hd
, parent
->backing_blocker
);
1268 /* Otherwise we won't be able to commit or stream */
1269 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_COMMIT_TARGET
,
1270 parent
->backing_blocker
);
1271 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_STREAM
,
1272 parent
->backing_blocker
);
1274 * We do backup in 3 ways:
1276 * The target bs is new opened, and the source is top BDS
1277 * 2. blockdev backup
1278 * Both the source and the target are top BDSes.
1279 * 3. internal backup(used for block replication)
1280 * Both the source and the target are backing file
1282 * In case 1 and 2, neither the source nor the target is the backing file.
1283 * In case 3, we will block the top BDS, so there is only one block job
1284 * for the top BDS and its backing chain.
1286 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_SOURCE
,
1287 parent
->backing_blocker
);
1288 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_TARGET
,
1289 parent
->backing_blocker
);
1292 static void bdrv_backing_detach(BdrvChild
*c
)
1294 BlockDriverState
*parent
= c
->opaque
;
1296 GLOBAL_STATE_CODE();
1297 assert(parent
->backing_blocker
);
1298 bdrv_op_unblock_all(c
->bs
, parent
->backing_blocker
);
1299 error_free(parent
->backing_blocker
);
1300 parent
->backing_blocker
= NULL
;
1303 static int bdrv_backing_update_filename(BdrvChild
*c
, BlockDriverState
*base
,
1304 const char *filename
, Error
**errp
)
1306 BlockDriverState
*parent
= c
->opaque
;
1307 bool read_only
= bdrv_is_read_only(parent
);
1309 GLOBAL_STATE_CODE();
1312 ret
= bdrv_reopen_set_read_only(parent
, false, errp
);
1318 ret
= bdrv_change_backing_file(parent
, filename
,
1319 base
->drv
? base
->drv
->format_name
: "",
1322 error_setg_errno(errp
, -ret
, "Could not update backing file link");
1326 bdrv_reopen_set_read_only(parent
, true, NULL
);
1333 * Returns the options and flags that a generic child of a BDS should
1334 * get, based on the given options and flags for the parent BDS.
1336 static void bdrv_inherited_options(BdrvChildRole role
, bool parent_is_format
,
1337 int *child_flags
, QDict
*child_options
,
1338 int parent_flags
, QDict
*parent_options
)
1340 int flags
= parent_flags
;
1341 GLOBAL_STATE_CODE();
1344 * First, decide whether to set, clear, or leave BDRV_O_PROTOCOL.
1345 * Generally, the question to answer is: Should this child be
1346 * format-probed by default?
1350 * Pure and non-filtered data children of non-format nodes should
1351 * be probed by default (even when the node itself has BDRV_O_PROTOCOL
1352 * set). This only affects a very limited set of drivers (namely
1353 * quorum and blkverify when this comment was written).
1354 * Force-clear BDRV_O_PROTOCOL then.
1356 if (!parent_is_format
&&
1357 (role
& BDRV_CHILD_DATA
) &&
1358 !(role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_FILTERED
)))
1360 flags
&= ~BDRV_O_PROTOCOL
;
1364 * All children of format nodes (except for COW children) and all
1365 * metadata children in general should never be format-probed.
1366 * Force-set BDRV_O_PROTOCOL then.
1368 if ((parent_is_format
&& !(role
& BDRV_CHILD_COW
)) ||
1369 (role
& BDRV_CHILD_METADATA
))
1371 flags
|= BDRV_O_PROTOCOL
;
1375 * If the cache mode isn't explicitly set, inherit direct and no-flush from
1378 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_DIRECT
);
1379 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_NO_FLUSH
);
1380 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_FORCE_SHARE
);
1382 if (role
& BDRV_CHILD_COW
) {
1383 /* backing files are opened read-only by default */
1384 qdict_set_default_str(child_options
, BDRV_OPT_READ_ONLY
, "on");
1385 qdict_set_default_str(child_options
, BDRV_OPT_AUTO_READ_ONLY
, "off");
1387 /* Inherit the read-only option from the parent if it's not set */
1388 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1389 qdict_copy_default(child_options
, parent_options
,
1390 BDRV_OPT_AUTO_READ_ONLY
);
1394 * bdrv_co_pdiscard() respects unmap policy for the parent, so we
1395 * can default to enable it on lower layers regardless of the
1398 qdict_set_default_str(child_options
, BDRV_OPT_DISCARD
, "unmap");
1400 /* Clear flags that only apply to the top layer */
1401 flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_COPY_ON_READ
);
1403 if (role
& BDRV_CHILD_METADATA
) {
1404 flags
&= ~BDRV_O_NO_IO
;
1406 if (role
& BDRV_CHILD_COW
) {
1407 flags
&= ~BDRV_O_TEMPORARY
;
1410 *child_flags
= flags
;
1413 static void GRAPH_WRLOCK
bdrv_child_cb_attach(BdrvChild
*child
)
1415 BlockDriverState
*bs
= child
->opaque
;
1417 assert_bdrv_graph_writable();
1418 QLIST_INSERT_HEAD(&bs
->children
, child
, next
);
1419 if (bs
->drv
->is_filter
|| (child
->role
& BDRV_CHILD_FILTERED
)) {
1421 * Here we handle filters and block/raw-format.c when it behave like
1422 * filter. They generally have a single PRIMARY child, which is also the
1423 * FILTERED child, and that they may have multiple more children, which
1424 * are neither PRIMARY nor FILTERED. And never we have a COW child here.
1425 * So bs->file will be the PRIMARY child, unless the PRIMARY child goes
1426 * into bs->backing on exceptional cases; and bs->backing will be
1429 assert(!(child
->role
& BDRV_CHILD_COW
));
1430 if (child
->role
& BDRV_CHILD_PRIMARY
) {
1431 assert(child
->role
& BDRV_CHILD_FILTERED
);
1432 assert(!bs
->backing
);
1435 if (bs
->drv
->filtered_child_is_backing
) {
1436 bs
->backing
= child
;
1441 assert(!(child
->role
& BDRV_CHILD_FILTERED
));
1443 } else if (child
->role
& BDRV_CHILD_COW
) {
1444 assert(bs
->drv
->supports_backing
);
1445 assert(!(child
->role
& BDRV_CHILD_PRIMARY
));
1446 assert(!bs
->backing
);
1447 bs
->backing
= child
;
1448 bdrv_backing_attach(child
);
1449 } else if (child
->role
& BDRV_CHILD_PRIMARY
) {
1455 static void GRAPH_WRLOCK
bdrv_child_cb_detach(BdrvChild
*child
)
1457 BlockDriverState
*bs
= child
->opaque
;
1459 if (child
->role
& BDRV_CHILD_COW
) {
1460 bdrv_backing_detach(child
);
1463 assert_bdrv_graph_writable();
1464 QLIST_REMOVE(child
, next
);
1465 if (child
== bs
->backing
) {
1466 assert(child
!= bs
->file
);
1468 } else if (child
== bs
->file
) {
1473 static int bdrv_child_cb_update_filename(BdrvChild
*c
, BlockDriverState
*base
,
1474 const char *filename
, Error
**errp
)
1476 if (c
->role
& BDRV_CHILD_COW
) {
1477 return bdrv_backing_update_filename(c
, base
, filename
, errp
);
1482 AioContext
*child_of_bds_get_parent_aio_context(BdrvChild
*c
)
1484 BlockDriverState
*bs
= c
->opaque
;
1487 return bdrv_get_aio_context(bs
);
1490 const BdrvChildClass child_of_bds
= {
1491 .parent_is_bds
= true,
1492 .get_parent_desc
= bdrv_child_get_parent_desc
,
1493 .inherit_options
= bdrv_inherited_options
,
1494 .drained_begin
= bdrv_child_cb_drained_begin
,
1495 .drained_poll
= bdrv_child_cb_drained_poll
,
1496 .drained_end
= bdrv_child_cb_drained_end
,
1497 .attach
= bdrv_child_cb_attach
,
1498 .detach
= bdrv_child_cb_detach
,
1499 .inactivate
= bdrv_child_cb_inactivate
,
1500 .change_aio_ctx
= bdrv_child_cb_change_aio_ctx
,
1501 .update_filename
= bdrv_child_cb_update_filename
,
1502 .get_parent_aio_context
= child_of_bds_get_parent_aio_context
,
1505 AioContext
*bdrv_child_get_parent_aio_context(BdrvChild
*c
)
1508 return c
->klass
->get_parent_aio_context(c
);
1511 static int bdrv_open_flags(BlockDriverState
*bs
, int flags
)
1513 int open_flags
= flags
;
1514 GLOBAL_STATE_CODE();
1517 * Clear flags that are internal to the block layer before opening the
1520 open_flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_PROTOCOL
);
1525 static void update_flags_from_options(int *flags
, QemuOpts
*opts
)
1527 GLOBAL_STATE_CODE();
1529 *flags
&= ~(BDRV_O_CACHE_MASK
| BDRV_O_RDWR
| BDRV_O_AUTO_RDONLY
);
1531 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_NO_FLUSH
, false)) {
1532 *flags
|= BDRV_O_NO_FLUSH
;
1535 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_DIRECT
, false)) {
1536 *flags
|= BDRV_O_NOCACHE
;
1539 if (!qemu_opt_get_bool_del(opts
, BDRV_OPT_READ_ONLY
, false)) {
1540 *flags
|= BDRV_O_RDWR
;
1543 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_AUTO_READ_ONLY
, false)) {
1544 *flags
|= BDRV_O_AUTO_RDONLY
;
1548 static void update_options_from_flags(QDict
*options
, int flags
)
1550 GLOBAL_STATE_CODE();
1551 if (!qdict_haskey(options
, BDRV_OPT_CACHE_DIRECT
)) {
1552 qdict_put_bool(options
, BDRV_OPT_CACHE_DIRECT
, flags
& BDRV_O_NOCACHE
);
1554 if (!qdict_haskey(options
, BDRV_OPT_CACHE_NO_FLUSH
)) {
1555 qdict_put_bool(options
, BDRV_OPT_CACHE_NO_FLUSH
,
1556 flags
& BDRV_O_NO_FLUSH
);
1558 if (!qdict_haskey(options
, BDRV_OPT_READ_ONLY
)) {
1559 qdict_put_bool(options
, BDRV_OPT_READ_ONLY
, !(flags
& BDRV_O_RDWR
));
1561 if (!qdict_haskey(options
, BDRV_OPT_AUTO_READ_ONLY
)) {
1562 qdict_put_bool(options
, BDRV_OPT_AUTO_READ_ONLY
,
1563 flags
& BDRV_O_AUTO_RDONLY
);
1567 static void bdrv_assign_node_name(BlockDriverState
*bs
,
1568 const char *node_name
,
1571 char *gen_node_name
= NULL
;
1572 GLOBAL_STATE_CODE();
1575 node_name
= gen_node_name
= id_generate(ID_BLOCK
);
1576 } else if (!id_wellformed(node_name
)) {
1578 * Check for empty string or invalid characters, but not if it is
1579 * generated (generated names use characters not available to the user)
1581 error_setg(errp
, "Invalid node-name: '%s'", node_name
);
1585 /* takes care of avoiding namespaces collisions */
1586 if (blk_by_name(node_name
)) {
1587 error_setg(errp
, "node-name=%s is conflicting with a device id",
1592 /* takes care of avoiding duplicates node names */
1593 if (bdrv_find_node(node_name
)) {
1594 error_setg(errp
, "Duplicate nodes with node-name='%s'", node_name
);
1598 /* Make sure that the node name isn't truncated */
1599 if (strlen(node_name
) >= sizeof(bs
->node_name
)) {
1600 error_setg(errp
, "Node name too long");
1604 /* copy node name into the bs and insert it into the graph list */
1605 pstrcpy(bs
->node_name
, sizeof(bs
->node_name
), node_name
);
1606 QTAILQ_INSERT_TAIL(&graph_bdrv_states
, bs
, node_list
);
1608 g_free(gen_node_name
);
1612 * The caller must always hold @bs AioContext lock, because this function calls
1613 * bdrv_refresh_total_sectors() which polls when called from non-coroutine
1616 static int no_coroutine_fn GRAPH_UNLOCKED
1617 bdrv_open_driver(BlockDriverState
*bs
, BlockDriver
*drv
, const char *node_name
,
1618 QDict
*options
, int open_flags
, Error
**errp
)
1621 Error
*local_err
= NULL
;
1623 GLOBAL_STATE_CODE();
1625 bdrv_assign_node_name(bs
, node_name
, &local_err
);
1627 error_propagate(errp
, local_err
);
1632 bs
->opaque
= g_malloc0(drv
->instance_size
);
1634 if (drv
->bdrv_file_open
) {
1635 assert(!drv
->bdrv_needs_filename
|| bs
->filename
[0]);
1636 ret
= drv
->bdrv_file_open(bs
, options
, open_flags
, &local_err
);
1637 } else if (drv
->bdrv_open
) {
1638 ret
= drv
->bdrv_open(bs
, options
, open_flags
, &local_err
);
1645 error_propagate(errp
, local_err
);
1646 } else if (bs
->filename
[0]) {
1647 error_setg_errno(errp
, -ret
, "Could not open '%s'", bs
->filename
);
1649 error_setg_errno(errp
, -ret
, "Could not open image");
1654 assert(!(bs
->supported_read_flags
& ~BDRV_REQ_MASK
));
1655 assert(!(bs
->supported_write_flags
& ~BDRV_REQ_MASK
));
1658 * Always allow the BDRV_REQ_REGISTERED_BUF optimization hint. This saves
1659 * drivers that pass read/write requests through to a child the trouble of
1660 * declaring support explicitly.
1662 * Drivers must not propagate this flag accidentally when they initiate I/O
1663 * to a bounce buffer. That case should be rare though.
1665 bs
->supported_read_flags
|= BDRV_REQ_REGISTERED_BUF
;
1666 bs
->supported_write_flags
|= BDRV_REQ_REGISTERED_BUF
;
1668 /* Get the context after .bdrv_open, it can change the context */
1669 ctx
= bdrv_get_aio_context(bs
);
1670 aio_context_acquire(ctx
);
1672 ret
= bdrv_refresh_total_sectors(bs
, bs
->total_sectors
);
1674 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
1675 aio_context_release(ctx
);
1679 bdrv_graph_rdlock_main_loop();
1680 bdrv_refresh_limits(bs
, NULL
, &local_err
);
1681 bdrv_graph_rdunlock_main_loop();
1682 aio_context_release(ctx
);
1685 error_propagate(errp
, local_err
);
1689 assert(bdrv_opt_mem_align(bs
) != 0);
1690 assert(bdrv_min_mem_align(bs
) != 0);
1691 assert(is_power_of_2(bs
->bl
.request_alignment
));
1693 for (i
= 0; i
< bs
->quiesce_counter
; i
++) {
1694 if (drv
->bdrv_drain_begin
) {
1695 drv
->bdrv_drain_begin(bs
);
1702 if (bs
->file
!= NULL
) {
1703 bdrv_unref_child(bs
, bs
->file
);
1712 * Create and open a block node.
1714 * @options is a QDict of options to pass to the block drivers, or NULL for an
1715 * empty set of options. The reference to the QDict belongs to the block layer
1716 * after the call (even on failure), so if the caller intends to reuse the
1717 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
1719 BlockDriverState
*bdrv_new_open_driver_opts(BlockDriver
*drv
,
1720 const char *node_name
,
1721 QDict
*options
, int flags
,
1724 BlockDriverState
*bs
;
1727 GLOBAL_STATE_CODE();
1730 bs
->open_flags
= flags
;
1731 bs
->options
= options
?: qdict_new();
1732 bs
->explicit_options
= qdict_clone_shallow(bs
->options
);
1735 update_options_from_flags(bs
->options
, flags
);
1737 ret
= bdrv_open_driver(bs
, drv
, node_name
, bs
->options
, flags
, errp
);
1739 qobject_unref(bs
->explicit_options
);
1740 bs
->explicit_options
= NULL
;
1741 qobject_unref(bs
->options
);
1750 /* Create and open a block node. */
1751 BlockDriverState
*bdrv_new_open_driver(BlockDriver
*drv
, const char *node_name
,
1752 int flags
, Error
**errp
)
1754 GLOBAL_STATE_CODE();
1755 return bdrv_new_open_driver_opts(drv
, node_name
, NULL
, flags
, errp
);
1758 QemuOptsList bdrv_runtime_opts
= {
1759 .name
= "bdrv_common",
1760 .head
= QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts
.head
),
1763 .name
= "node-name",
1764 .type
= QEMU_OPT_STRING
,
1765 .help
= "Node name of the block device node",
1769 .type
= QEMU_OPT_STRING
,
1770 .help
= "Block driver to use for the node",
1773 .name
= BDRV_OPT_CACHE_DIRECT
,
1774 .type
= QEMU_OPT_BOOL
,
1775 .help
= "Bypass software writeback cache on the host",
1778 .name
= BDRV_OPT_CACHE_NO_FLUSH
,
1779 .type
= QEMU_OPT_BOOL
,
1780 .help
= "Ignore flush requests",
1783 .name
= BDRV_OPT_READ_ONLY
,
1784 .type
= QEMU_OPT_BOOL
,
1785 .help
= "Node is opened in read-only mode",
1788 .name
= BDRV_OPT_AUTO_READ_ONLY
,
1789 .type
= QEMU_OPT_BOOL
,
1790 .help
= "Node can become read-only if opening read-write fails",
1793 .name
= "detect-zeroes",
1794 .type
= QEMU_OPT_STRING
,
1795 .help
= "try to optimize zero writes (off, on, unmap)",
1798 .name
= BDRV_OPT_DISCARD
,
1799 .type
= QEMU_OPT_STRING
,
1800 .help
= "discard operation (ignore/off, unmap/on)",
1803 .name
= BDRV_OPT_FORCE_SHARE
,
1804 .type
= QEMU_OPT_BOOL
,
1805 .help
= "always accept other writers (default: off)",
1807 { /* end of list */ }
1811 QemuOptsList bdrv_create_opts_simple
= {
1812 .name
= "simple-create-opts",
1813 .head
= QTAILQ_HEAD_INITIALIZER(bdrv_create_opts_simple
.head
),
1816 .name
= BLOCK_OPT_SIZE
,
1817 .type
= QEMU_OPT_SIZE
,
1818 .help
= "Virtual disk size"
1821 .name
= BLOCK_OPT_PREALLOC
,
1822 .type
= QEMU_OPT_STRING
,
1823 .help
= "Preallocation mode (allowed values: off)"
1825 { /* end of list */ }
1830 * Common part for opening disk images and files
1832 * Removes all processed options from *options.
1834 static int bdrv_open_common(BlockDriverState
*bs
, BlockBackend
*file
,
1835 QDict
*options
, Error
**errp
)
1837 int ret
, open_flags
;
1838 const char *filename
;
1839 const char *driver_name
= NULL
;
1840 const char *node_name
= NULL
;
1841 const char *discard
;
1844 Error
*local_err
= NULL
;
1847 assert(bs
->file
== NULL
);
1848 assert(options
!= NULL
&& bs
->options
!= options
);
1849 GLOBAL_STATE_CODE();
1851 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
1852 if (!qemu_opts_absorb_qdict(opts
, options
, errp
)) {
1857 update_flags_from_options(&bs
->open_flags
, opts
);
1859 driver_name
= qemu_opt_get(opts
, "driver");
1860 drv
= bdrv_find_format(driver_name
);
1861 assert(drv
!= NULL
);
1863 bs
->force_share
= qemu_opt_get_bool(opts
, BDRV_OPT_FORCE_SHARE
, false);
1865 if (bs
->force_share
&& (bs
->open_flags
& BDRV_O_RDWR
)) {
1867 BDRV_OPT_FORCE_SHARE
1868 "=on can only be used with read-only images");
1874 bdrv_refresh_filename(blk_bs(file
));
1875 filename
= blk_bs(file
)->filename
;
1878 * Caution: while qdict_get_try_str() is fine, getting
1879 * non-string types would require more care. When @options
1880 * come from -blockdev or blockdev_add, its members are typed
1881 * according to the QAPI schema, but when they come from
1882 * -drive, they're all QString.
1884 filename
= qdict_get_try_str(options
, "filename");
1887 if (drv
->bdrv_needs_filename
&& (!filename
|| !filename
[0])) {
1888 error_setg(errp
, "The '%s' block driver requires a file name",
1894 trace_bdrv_open_common(bs
, filename
?: "", bs
->open_flags
,
1897 ro
= bdrv_is_read_only(bs
);
1899 if (use_bdrv_whitelist
&& !bdrv_is_whitelisted(drv
, ro
)) {
1900 if (!ro
&& bdrv_is_whitelisted(drv
, true)) {
1901 ret
= bdrv_apply_auto_read_only(bs
, NULL
, NULL
);
1907 !ro
&& bdrv_is_whitelisted(drv
, true)
1908 ? "Driver '%s' can only be used for read-only devices"
1909 : "Driver '%s' is not whitelisted",
1915 /* bdrv_new() and bdrv_close() make it so */
1916 assert(qatomic_read(&bs
->copy_on_read
) == 0);
1918 if (bs
->open_flags
& BDRV_O_COPY_ON_READ
) {
1920 bdrv_enable_copy_on_read(bs
);
1922 error_setg(errp
, "Can't use copy-on-read on read-only device");
1928 discard
= qemu_opt_get(opts
, BDRV_OPT_DISCARD
);
1929 if (discard
!= NULL
) {
1930 if (bdrv_parse_discard_flags(discard
, &bs
->open_flags
) != 0) {
1931 error_setg(errp
, "Invalid discard option");
1938 bdrv_parse_detect_zeroes(opts
, bs
->open_flags
, &local_err
);
1940 error_propagate(errp
, local_err
);
1945 if (filename
!= NULL
) {
1946 pstrcpy(bs
->filename
, sizeof(bs
->filename
), filename
);
1948 bs
->filename
[0] = '\0';
1950 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
), bs
->filename
);
1952 /* Open the image, either directly or using a protocol */
1953 open_flags
= bdrv_open_flags(bs
, bs
->open_flags
);
1954 node_name
= qemu_opt_get(opts
, "node-name");
1956 assert(!drv
->bdrv_file_open
|| file
== NULL
);
1957 ret
= bdrv_open_driver(bs
, drv
, node_name
, options
, open_flags
, errp
);
1962 qemu_opts_del(opts
);
1966 qemu_opts_del(opts
);
1970 static QDict
*parse_json_filename(const char *filename
, Error
**errp
)
1972 QObject
*options_obj
;
1975 GLOBAL_STATE_CODE();
1977 ret
= strstart(filename
, "json:", &filename
);
1980 options_obj
= qobject_from_json(filename
, errp
);
1982 error_prepend(errp
, "Could not parse the JSON options: ");
1986 options
= qobject_to(QDict
, options_obj
);
1988 qobject_unref(options_obj
);
1989 error_setg(errp
, "Invalid JSON object given");
1993 qdict_flatten(options
);
1998 static void parse_json_protocol(QDict
*options
, const char **pfilename
,
2001 QDict
*json_options
;
2002 Error
*local_err
= NULL
;
2003 GLOBAL_STATE_CODE();
2005 /* Parse json: pseudo-protocol */
2006 if (!*pfilename
|| !g_str_has_prefix(*pfilename
, "json:")) {
2010 json_options
= parse_json_filename(*pfilename
, &local_err
);
2012 error_propagate(errp
, local_err
);
2016 /* Options given in the filename have lower priority than options
2017 * specified directly */
2018 qdict_join(options
, json_options
, false);
2019 qobject_unref(json_options
);
2024 * Fills in default options for opening images and converts the legacy
2025 * filename/flags pair to option QDict entries.
2026 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
2027 * block driver has been specified explicitly.
2029 static int bdrv_fill_options(QDict
**options
, const char *filename
,
2030 int *flags
, Error
**errp
)
2032 const char *drvname
;
2033 bool protocol
= *flags
& BDRV_O_PROTOCOL
;
2034 bool parse_filename
= false;
2035 BlockDriver
*drv
= NULL
;
2036 Error
*local_err
= NULL
;
2038 GLOBAL_STATE_CODE();
2041 * Caution: while qdict_get_try_str() is fine, getting non-string
2042 * types would require more care. When @options come from
2043 * -blockdev or blockdev_add, its members are typed according to
2044 * the QAPI schema, but when they come from -drive, they're all
2047 drvname
= qdict_get_try_str(*options
, "driver");
2049 drv
= bdrv_find_format(drvname
);
2051 error_setg(errp
, "Unknown driver '%s'", drvname
);
2054 /* If the user has explicitly specified the driver, this choice should
2055 * override the BDRV_O_PROTOCOL flag */
2056 protocol
= drv
->bdrv_file_open
;
2060 *flags
|= BDRV_O_PROTOCOL
;
2062 *flags
&= ~BDRV_O_PROTOCOL
;
2065 /* Translate cache options from flags into options */
2066 update_options_from_flags(*options
, *flags
);
2068 /* Fetch the file name from the options QDict if necessary */
2069 if (protocol
&& filename
) {
2070 if (!qdict_haskey(*options
, "filename")) {
2071 qdict_put_str(*options
, "filename", filename
);
2072 parse_filename
= true;
2074 error_setg(errp
, "Can't specify 'file' and 'filename' options at "
2080 /* Find the right block driver */
2081 /* See cautionary note on accessing @options above */
2082 filename
= qdict_get_try_str(*options
, "filename");
2084 if (!drvname
&& protocol
) {
2086 drv
= bdrv_find_protocol(filename
, parse_filename
, errp
);
2091 drvname
= drv
->format_name
;
2092 qdict_put_str(*options
, "driver", drvname
);
2094 error_setg(errp
, "Must specify either driver or file");
2099 assert(drv
|| !protocol
);
2101 /* Driver-specific filename parsing */
2102 if (drv
&& drv
->bdrv_parse_filename
&& parse_filename
) {
2103 drv
->bdrv_parse_filename(filename
, *options
, &local_err
);
2105 error_propagate(errp
, local_err
);
2109 if (!drv
->bdrv_needs_filename
) {
2110 qdict_del(*options
, "filename");
2117 typedef struct BlockReopenQueueEntry
{
2119 BDRVReopenState state
;
2120 QTAILQ_ENTRY(BlockReopenQueueEntry
) entry
;
2121 } BlockReopenQueueEntry
;
2124 * Return the flags that @bs will have after the reopens in @q have
2125 * successfully completed. If @q is NULL (or @bs is not contained in @q),
2126 * return the current flags.
2128 static int bdrv_reopen_get_flags(BlockReopenQueue
*q
, BlockDriverState
*bs
)
2130 BlockReopenQueueEntry
*entry
;
2133 QTAILQ_FOREACH(entry
, q
, entry
) {
2134 if (entry
->state
.bs
== bs
) {
2135 return entry
->state
.flags
;
2140 return bs
->open_flags
;
2143 /* Returns whether the image file can be written to after the reopen queue @q
2144 * has been successfully applied, or right now if @q is NULL. */
2145 static bool bdrv_is_writable_after_reopen(BlockDriverState
*bs
,
2146 BlockReopenQueue
*q
)
2148 int flags
= bdrv_reopen_get_flags(q
, bs
);
2150 return (flags
& (BDRV_O_RDWR
| BDRV_O_INACTIVE
)) == BDRV_O_RDWR
;
2154 * Return whether the BDS can be written to. This is not necessarily
2155 * the same as !bdrv_is_read_only(bs), as inactivated images may not
2156 * be written to but do not count as read-only images.
2158 bool bdrv_is_writable(BlockDriverState
*bs
)
2161 return bdrv_is_writable_after_reopen(bs
, NULL
);
2164 static char *bdrv_child_user_desc(BdrvChild
*c
)
2166 GLOBAL_STATE_CODE();
2167 return c
->klass
->get_parent_desc(c
);
2171 * Check that @a allows everything that @b needs. @a and @b must reference same
2174 static bool bdrv_a_allow_b(BdrvChild
*a
, BdrvChild
*b
, Error
**errp
)
2176 const char *child_bs_name
;
2177 g_autofree
char *a_user
= NULL
;
2178 g_autofree
char *b_user
= NULL
;
2179 g_autofree
char *perms
= NULL
;
2182 assert(a
->bs
== b
->bs
);
2183 GLOBAL_STATE_CODE();
2185 if ((b
->perm
& a
->shared_perm
) == b
->perm
) {
2189 child_bs_name
= bdrv_get_node_name(b
->bs
);
2190 a_user
= bdrv_child_user_desc(a
);
2191 b_user
= bdrv_child_user_desc(b
);
2192 perms
= bdrv_perm_names(b
->perm
& ~a
->shared_perm
);
2194 error_setg(errp
, "Permission conflict on node '%s': permissions '%s' are "
2195 "both required by %s (uses node '%s' as '%s' child) and "
2196 "unshared by %s (uses node '%s' as '%s' child).",
2197 child_bs_name
, perms
,
2198 b_user
, child_bs_name
, b
->name
,
2199 a_user
, child_bs_name
, a
->name
);
2204 static bool bdrv_parent_perms_conflict(BlockDriverState
*bs
, Error
**errp
)
2207 GLOBAL_STATE_CODE();
2210 * During the loop we'll look at each pair twice. That's correct because
2211 * bdrv_a_allow_b() is asymmetric and we should check each pair in both
2214 QLIST_FOREACH(a
, &bs
->parents
, next_parent
) {
2215 QLIST_FOREACH(b
, &bs
->parents
, next_parent
) {
2220 if (!bdrv_a_allow_b(a
, b
, errp
)) {
2229 static void bdrv_child_perm(BlockDriverState
*bs
, BlockDriverState
*child_bs
,
2230 BdrvChild
*c
, BdrvChildRole role
,
2231 BlockReopenQueue
*reopen_queue
,
2232 uint64_t parent_perm
, uint64_t parent_shared
,
2233 uint64_t *nperm
, uint64_t *nshared
)
2235 assert(bs
->drv
&& bs
->drv
->bdrv_child_perm
);
2236 GLOBAL_STATE_CODE();
2237 bs
->drv
->bdrv_child_perm(bs
, c
, role
, reopen_queue
,
2238 parent_perm
, parent_shared
,
2240 /* TODO Take force_share from reopen_queue */
2241 if (child_bs
&& child_bs
->force_share
) {
2242 *nshared
= BLK_PERM_ALL
;
2247 * Adds the whole subtree of @bs (including @bs itself) to the @list (except for
2248 * nodes that are already in the @list, of course) so that final list is
2249 * topologically sorted. Return the result (GSList @list object is updated, so
2250 * don't use old reference after function call).
2252 * On function start @list must be already topologically sorted and for any node
2253 * in the @list the whole subtree of the node must be in the @list as well. The
2254 * simplest way to satisfy this criteria: use only result of
2255 * bdrv_topological_dfs() or NULL as @list parameter.
2257 static GSList
*bdrv_topological_dfs(GSList
*list
, GHashTable
*found
,
2258 BlockDriverState
*bs
)
2261 g_autoptr(GHashTable
) local_found
= NULL
;
2263 GLOBAL_STATE_CODE();
2267 found
= local_found
= g_hash_table_new(NULL
, NULL
);
2270 if (g_hash_table_contains(found
, bs
)) {
2273 g_hash_table_add(found
, bs
);
2275 QLIST_FOREACH(child
, &bs
->children
, next
) {
2276 list
= bdrv_topological_dfs(list
, found
, child
->bs
);
2279 return g_slist_prepend(list
, bs
);
2282 typedef struct BdrvChildSetPermState
{
2285 uint64_t old_shared_perm
;
2286 } BdrvChildSetPermState
;
2288 static void bdrv_child_set_perm_abort(void *opaque
)
2290 BdrvChildSetPermState
*s
= opaque
;
2292 GLOBAL_STATE_CODE();
2294 s
->child
->perm
= s
->old_perm
;
2295 s
->child
->shared_perm
= s
->old_shared_perm
;
2298 static TransactionActionDrv bdrv_child_set_pem_drv
= {
2299 .abort
= bdrv_child_set_perm_abort
,
2303 static void bdrv_child_set_perm(BdrvChild
*c
, uint64_t perm
,
2304 uint64_t shared
, Transaction
*tran
)
2306 BdrvChildSetPermState
*s
= g_new(BdrvChildSetPermState
, 1);
2307 GLOBAL_STATE_CODE();
2309 *s
= (BdrvChildSetPermState
) {
2311 .old_perm
= c
->perm
,
2312 .old_shared_perm
= c
->shared_perm
,
2316 c
->shared_perm
= shared
;
2318 tran_add(tran
, &bdrv_child_set_pem_drv
, s
);
2321 static void bdrv_drv_set_perm_commit(void *opaque
)
2323 BlockDriverState
*bs
= opaque
;
2324 uint64_t cumulative_perms
, cumulative_shared_perms
;
2325 GLOBAL_STATE_CODE();
2327 if (bs
->drv
->bdrv_set_perm
) {
2328 bdrv_get_cumulative_perm(bs
, &cumulative_perms
,
2329 &cumulative_shared_perms
);
2330 bs
->drv
->bdrv_set_perm(bs
, cumulative_perms
, cumulative_shared_perms
);
2334 static void bdrv_drv_set_perm_abort(void *opaque
)
2336 BlockDriverState
*bs
= opaque
;
2337 GLOBAL_STATE_CODE();
2339 if (bs
->drv
->bdrv_abort_perm_update
) {
2340 bs
->drv
->bdrv_abort_perm_update(bs
);
2344 TransactionActionDrv bdrv_drv_set_perm_drv
= {
2345 .abort
= bdrv_drv_set_perm_abort
,
2346 .commit
= bdrv_drv_set_perm_commit
,
2349 static int bdrv_drv_set_perm(BlockDriverState
*bs
, uint64_t perm
,
2350 uint64_t shared_perm
, Transaction
*tran
,
2353 GLOBAL_STATE_CODE();
2358 if (bs
->drv
->bdrv_check_perm
) {
2359 int ret
= bs
->drv
->bdrv_check_perm(bs
, perm
, shared_perm
, errp
);
2366 tran_add(tran
, &bdrv_drv_set_perm_drv
, bs
);
2372 typedef struct BdrvReplaceChildState
{
2374 BlockDriverState
*old_bs
;
2375 } BdrvReplaceChildState
;
2377 static void bdrv_replace_child_commit(void *opaque
)
2379 BdrvReplaceChildState
*s
= opaque
;
2380 GLOBAL_STATE_CODE();
2382 bdrv_unref(s
->old_bs
);
2385 static void bdrv_replace_child_abort(void *opaque
)
2387 BdrvReplaceChildState
*s
= opaque
;
2388 BlockDriverState
*new_bs
= s
->child
->bs
;
2390 GLOBAL_STATE_CODE();
2391 bdrv_graph_wrlock(s
->old_bs
);
2393 /* old_bs reference is transparently moved from @s to @s->child */
2394 if (!s
->child
->bs
) {
2396 * The parents were undrained when removing old_bs from the child. New
2397 * requests can't have been made, though, because the child was empty.
2399 * TODO Make bdrv_replace_child_noperm() transactionable to avoid
2400 * undraining the parent in the first place. Once this is done, having
2401 * new_bs drained when calling bdrv_replace_child_tran() is not a
2402 * requirement any more.
2404 bdrv_parent_drained_begin_single(s
->child
);
2405 assert(!bdrv_parent_drained_poll_single(s
->child
));
2407 assert(s
->child
->quiesced_parent
);
2408 bdrv_replace_child_noperm(s
->child
, s
->old_bs
);
2410 bdrv_graph_wrunlock();
2414 static TransactionActionDrv bdrv_replace_child_drv
= {
2415 .commit
= bdrv_replace_child_commit
,
2416 .abort
= bdrv_replace_child_abort
,
2421 * bdrv_replace_child_tran
2423 * Note: real unref of old_bs is done only on commit.
2425 * Both @child->bs and @new_bs (if non-NULL) must be drained. @new_bs must be
2426 * kept drained until the transaction is completed.
2428 * The function doesn't update permissions, caller is responsible for this.
2430 static void bdrv_replace_child_tran(BdrvChild
*child
, BlockDriverState
*new_bs
,
2433 BdrvReplaceChildState
*s
= g_new(BdrvReplaceChildState
, 1);
2435 assert(child
->quiesced_parent
);
2436 assert(!new_bs
|| new_bs
->quiesce_counter
);
2438 *s
= (BdrvReplaceChildState
) {
2440 .old_bs
= child
->bs
,
2442 tran_add(tran
, &bdrv_replace_child_drv
, s
);
2448 bdrv_graph_wrlock(new_bs
);
2449 bdrv_replace_child_noperm(child
, new_bs
);
2450 bdrv_graph_wrunlock();
2451 /* old_bs reference is transparently moved from @child to @s */
2455 * Refresh permissions in @bs subtree. The function is intended to be called
2456 * after some graph modification that was done without permission update.
2458 static int bdrv_node_refresh_perm(BlockDriverState
*bs
, BlockReopenQueue
*q
,
2459 Transaction
*tran
, Error
**errp
)
2461 BlockDriver
*drv
= bs
->drv
;
2464 uint64_t cumulative_perms
, cumulative_shared_perms
;
2465 GLOBAL_STATE_CODE();
2467 bdrv_get_cumulative_perm(bs
, &cumulative_perms
, &cumulative_shared_perms
);
2469 /* Write permissions never work with read-only images */
2470 if ((cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) &&
2471 !bdrv_is_writable_after_reopen(bs
, q
))
2473 if (!bdrv_is_writable_after_reopen(bs
, NULL
)) {
2474 error_setg(errp
, "Block node is read-only");
2476 error_setg(errp
, "Read-only block node '%s' cannot support "
2477 "read-write users", bdrv_get_node_name(bs
));
2484 * Unaligned requests will automatically be aligned to bl.request_alignment
2485 * and without RESIZE we can't extend requests to write to space beyond the
2486 * end of the image, so it's required that the image size is aligned.
2488 if ((cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) &&
2489 !(cumulative_perms
& BLK_PERM_RESIZE
))
2491 if ((bs
->total_sectors
* BDRV_SECTOR_SIZE
) % bs
->bl
.request_alignment
) {
2492 error_setg(errp
, "Cannot get 'write' permission without 'resize': "
2493 "Image size is not a multiple of request "
2499 /* Check this node */
2504 ret
= bdrv_drv_set_perm(bs
, cumulative_perms
, cumulative_shared_perms
, tran
,
2510 /* Drivers that never have children can omit .bdrv_child_perm() */
2511 if (!drv
->bdrv_child_perm
) {
2512 assert(QLIST_EMPTY(&bs
->children
));
2516 /* Check all children */
2517 QLIST_FOREACH(c
, &bs
->children
, next
) {
2518 uint64_t cur_perm
, cur_shared
;
2520 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, q
,
2521 cumulative_perms
, cumulative_shared_perms
,
2522 &cur_perm
, &cur_shared
);
2523 bdrv_child_set_perm(c
, cur_perm
, cur_shared
, tran
);
2530 * @list is a product of bdrv_topological_dfs() (may be called several times) -
2531 * a topologically sorted subgraph.
2533 static int bdrv_do_refresh_perms(GSList
*list
, BlockReopenQueue
*q
,
2534 Transaction
*tran
, Error
**errp
)
2537 BlockDriverState
*bs
;
2538 GLOBAL_STATE_CODE();
2540 for ( ; list
; list
= list
->next
) {
2543 if (bdrv_parent_perms_conflict(bs
, errp
)) {
2547 ret
= bdrv_node_refresh_perm(bs
, q
, tran
, errp
);
2557 * @list is any list of nodes. List is completed by all subtrees and
2558 * topologically sorted. It's not a problem if some node occurs in the @list
2561 static int bdrv_list_refresh_perms(GSList
*list
, BlockReopenQueue
*q
,
2562 Transaction
*tran
, Error
**errp
)
2564 g_autoptr(GHashTable
) found
= g_hash_table_new(NULL
, NULL
);
2565 g_autoptr(GSList
) refresh_list
= NULL
;
2567 for ( ; list
; list
= list
->next
) {
2568 refresh_list
= bdrv_topological_dfs(refresh_list
, found
, list
->data
);
2571 return bdrv_do_refresh_perms(refresh_list
, q
, tran
, errp
);
2574 void bdrv_get_cumulative_perm(BlockDriverState
*bs
, uint64_t *perm
,
2575 uint64_t *shared_perm
)
2578 uint64_t cumulative_perms
= 0;
2579 uint64_t cumulative_shared_perms
= BLK_PERM_ALL
;
2581 GLOBAL_STATE_CODE();
2583 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
2584 cumulative_perms
|= c
->perm
;
2585 cumulative_shared_perms
&= c
->shared_perm
;
2588 *perm
= cumulative_perms
;
2589 *shared_perm
= cumulative_shared_perms
;
2592 char *bdrv_perm_names(uint64_t perm
)
2598 { BLK_PERM_CONSISTENT_READ
, "consistent read" },
2599 { BLK_PERM_WRITE
, "write" },
2600 { BLK_PERM_WRITE_UNCHANGED
, "write unchanged" },
2601 { BLK_PERM_RESIZE
, "resize" },
2605 GString
*result
= g_string_sized_new(30);
2606 struct perm_name
*p
;
2608 for (p
= permissions
; p
->name
; p
++) {
2609 if (perm
& p
->perm
) {
2610 if (result
->len
> 0) {
2611 g_string_append(result
, ", ");
2613 g_string_append(result
, p
->name
);
2617 return g_string_free(result
, FALSE
);
2621 /* @tran is allowed to be NULL. In this case no rollback is possible */
2622 static int bdrv_refresh_perms(BlockDriverState
*bs
, Transaction
*tran
,
2626 Transaction
*local_tran
= NULL
;
2627 g_autoptr(GSList
) list
= bdrv_topological_dfs(NULL
, NULL
, bs
);
2628 GLOBAL_STATE_CODE();
2631 tran
= local_tran
= tran_new();
2634 ret
= bdrv_do_refresh_perms(list
, NULL
, tran
, errp
);
2637 tran_finalize(local_tran
, ret
);
2643 int bdrv_child_try_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
,
2646 Error
*local_err
= NULL
;
2647 Transaction
*tran
= tran_new();
2650 GLOBAL_STATE_CODE();
2652 bdrv_child_set_perm(c
, perm
, shared
, tran
);
2654 ret
= bdrv_refresh_perms(c
->bs
, tran
, &local_err
);
2656 tran_finalize(tran
, ret
);
2659 if ((perm
& ~c
->perm
) || (c
->shared_perm
& ~shared
)) {
2660 /* tighten permissions */
2661 error_propagate(errp
, local_err
);
2664 * Our caller may intend to only loosen restrictions and
2665 * does not expect this function to fail. Errors are not
2666 * fatal in such a case, so we can just hide them from our
2669 error_free(local_err
);
2677 int bdrv_child_refresh_perms(BlockDriverState
*bs
, BdrvChild
*c
, Error
**errp
)
2679 uint64_t parent_perms
, parent_shared
;
2680 uint64_t perms
, shared
;
2682 GLOBAL_STATE_CODE();
2684 bdrv_get_cumulative_perm(bs
, &parent_perms
, &parent_shared
);
2685 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, NULL
,
2686 parent_perms
, parent_shared
, &perms
, &shared
);
2688 return bdrv_child_try_set_perm(c
, perms
, shared
, errp
);
2692 * Default implementation for .bdrv_child_perm() for block filters:
2693 * Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED, and RESIZE to the
2696 static void bdrv_filter_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2698 BlockReopenQueue
*reopen_queue
,
2699 uint64_t perm
, uint64_t shared
,
2700 uint64_t *nperm
, uint64_t *nshared
)
2702 GLOBAL_STATE_CODE();
2703 *nperm
= perm
& DEFAULT_PERM_PASSTHROUGH
;
2704 *nshared
= (shared
& DEFAULT_PERM_PASSTHROUGH
) | DEFAULT_PERM_UNCHANGED
;
2707 static void bdrv_default_perms_for_cow(BlockDriverState
*bs
, BdrvChild
*c
,
2709 BlockReopenQueue
*reopen_queue
,
2710 uint64_t perm
, uint64_t shared
,
2711 uint64_t *nperm
, uint64_t *nshared
)
2713 assert(role
& BDRV_CHILD_COW
);
2714 GLOBAL_STATE_CODE();
2717 * We want consistent read from backing files if the parent needs it.
2718 * No other operations are performed on backing files.
2720 perm
&= BLK_PERM_CONSISTENT_READ
;
2723 * If the parent can deal with changing data, we're okay with a
2724 * writable and resizable backing file.
2725 * TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too?
2727 if (shared
& BLK_PERM_WRITE
) {
2728 shared
= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2733 shared
|= BLK_PERM_CONSISTENT_READ
| BLK_PERM_WRITE_UNCHANGED
;
2735 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
2736 shared
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2743 static void bdrv_default_perms_for_storage(BlockDriverState
*bs
, BdrvChild
*c
,
2745 BlockReopenQueue
*reopen_queue
,
2746 uint64_t perm
, uint64_t shared
,
2747 uint64_t *nperm
, uint64_t *nshared
)
2751 GLOBAL_STATE_CODE();
2752 assert(role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_DATA
));
2754 flags
= bdrv_reopen_get_flags(reopen_queue
, bs
);
2757 * Apart from the modifications below, the same permissions are
2758 * forwarded and left alone as for filters
2760 bdrv_filter_default_perms(bs
, c
, role
, reopen_queue
,
2761 perm
, shared
, &perm
, &shared
);
2763 if (role
& BDRV_CHILD_METADATA
) {
2764 /* Format drivers may touch metadata even if the guest doesn't write */
2765 if (bdrv_is_writable_after_reopen(bs
, reopen_queue
)) {
2766 perm
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2770 * bs->file always needs to be consistent because of the
2771 * metadata. We can never allow other users to resize or write
2774 if (!(flags
& BDRV_O_NO_IO
)) {
2775 perm
|= BLK_PERM_CONSISTENT_READ
;
2777 shared
&= ~(BLK_PERM_WRITE
| BLK_PERM_RESIZE
);
2780 if (role
& BDRV_CHILD_DATA
) {
2782 * Technically, everything in this block is a subset of the
2783 * BDRV_CHILD_METADATA path taken above, and so this could
2784 * be an "else if" branch. However, that is not obvious, and
2785 * this function is not performance critical, therefore we let
2786 * this be an independent "if".
2790 * We cannot allow other users to resize the file because the
2791 * format driver might have some assumptions about the size
2792 * (e.g. because it is stored in metadata, or because the file
2793 * is split into fixed-size data files).
2795 shared
&= ~BLK_PERM_RESIZE
;
2798 * WRITE_UNCHANGED often cannot be performed as such on the
2799 * data file. For example, the qcow2 driver may still need to
2800 * write copied clusters on copy-on-read.
2802 if (perm
& BLK_PERM_WRITE_UNCHANGED
) {
2803 perm
|= BLK_PERM_WRITE
;
2807 * If the data file is written to, the format driver may
2808 * expect to be able to resize it by writing beyond the EOF.
2810 if (perm
& BLK_PERM_WRITE
) {
2811 perm
|= BLK_PERM_RESIZE
;
2815 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
2816 shared
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2823 void bdrv_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2824 BdrvChildRole role
, BlockReopenQueue
*reopen_queue
,
2825 uint64_t perm
, uint64_t shared
,
2826 uint64_t *nperm
, uint64_t *nshared
)
2828 GLOBAL_STATE_CODE();
2829 if (role
& BDRV_CHILD_FILTERED
) {
2830 assert(!(role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
|
2832 bdrv_filter_default_perms(bs
, c
, role
, reopen_queue
,
2833 perm
, shared
, nperm
, nshared
);
2834 } else if (role
& BDRV_CHILD_COW
) {
2835 assert(!(role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
)));
2836 bdrv_default_perms_for_cow(bs
, c
, role
, reopen_queue
,
2837 perm
, shared
, nperm
, nshared
);
2838 } else if (role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_DATA
)) {
2839 bdrv_default_perms_for_storage(bs
, c
, role
, reopen_queue
,
2840 perm
, shared
, nperm
, nshared
);
2842 g_assert_not_reached();
2846 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm
)
2848 static const uint64_t permissions
[] = {
2849 [BLOCK_PERMISSION_CONSISTENT_READ
] = BLK_PERM_CONSISTENT_READ
,
2850 [BLOCK_PERMISSION_WRITE
] = BLK_PERM_WRITE
,
2851 [BLOCK_PERMISSION_WRITE_UNCHANGED
] = BLK_PERM_WRITE_UNCHANGED
,
2852 [BLOCK_PERMISSION_RESIZE
] = BLK_PERM_RESIZE
,
2855 QEMU_BUILD_BUG_ON(ARRAY_SIZE(permissions
) != BLOCK_PERMISSION__MAX
);
2856 QEMU_BUILD_BUG_ON(1UL << ARRAY_SIZE(permissions
) != BLK_PERM_ALL
+ 1);
2858 assert(qapi_perm
< BLOCK_PERMISSION__MAX
);
2860 return permissions
[qapi_perm
];
2864 * Replaces the node that a BdrvChild points to without updating permissions.
2866 * If @new_bs is non-NULL, the parent of @child must already be drained through
2867 * @child and the caller must hold the AioContext lock for @new_bs.
2869 static void GRAPH_WRLOCK
2870 bdrv_replace_child_noperm(BdrvChild
*child
, BlockDriverState
*new_bs
)
2872 BlockDriverState
*old_bs
= child
->bs
;
2873 int new_bs_quiesce_counter
;
2875 assert(!child
->frozen
);
2878 * If we want to change the BdrvChild to point to a drained node as its new
2879 * child->bs, we need to make sure that its new parent is drained, too. In
2880 * other words, either child->quiesce_parent must already be true or we must
2881 * be able to set it and keep the parent's quiesce_counter consistent with
2882 * that, but without polling or starting new requests (this function
2883 * guarantees that it doesn't poll, and starting new requests would be
2884 * against the invariants of drain sections).
2886 * To keep things simple, we pick the first option (child->quiesce_parent
2887 * must already be true). We also generalise the rule a bit to make it
2888 * easier to verify in callers and more likely to be covered in test cases:
2889 * The parent must be quiesced through this child even if new_bs isn't
2890 * currently drained.
2892 * The only exception is for callers that always pass new_bs == NULL. In
2893 * this case, we obviously never need to consider the case of a drained
2894 * new_bs, so we can keep the callers simpler by allowing them not to drain
2897 assert(!new_bs
|| child
->quiesced_parent
);
2898 assert(old_bs
!= new_bs
);
2899 GLOBAL_STATE_CODE();
2901 if (old_bs
&& new_bs
) {
2902 assert(bdrv_get_aio_context(old_bs
) == bdrv_get_aio_context(new_bs
));
2906 if (child
->klass
->detach
) {
2907 child
->klass
->detach(child
);
2909 QLIST_REMOVE(child
, next_parent
);
2915 QLIST_INSERT_HEAD(&new_bs
->parents
, child
, next_parent
);
2916 if (child
->klass
->attach
) {
2917 child
->klass
->attach(child
);
2922 * If the parent was drained through this BdrvChild previously, but new_bs
2923 * is not drained, allow requests to come in only after the new node has
2926 new_bs_quiesce_counter
= (new_bs
? new_bs
->quiesce_counter
: 0);
2927 if (!new_bs_quiesce_counter
&& child
->quiesced_parent
) {
2928 bdrv_parent_drained_end_single(child
);
2933 * Free the given @child.
2935 * The child must be empty (i.e. `child->bs == NULL`) and it must be
2936 * unused (i.e. not in a children list).
2938 static void bdrv_child_free(BdrvChild
*child
)
2941 GLOBAL_STATE_CODE();
2942 assert(!child
->next
.le_prev
); /* not in children list */
2944 g_free(child
->name
);
2948 typedef struct BdrvAttachChildCommonState
{
2950 AioContext
*old_parent_ctx
;
2951 AioContext
*old_child_ctx
;
2952 } BdrvAttachChildCommonState
;
2954 static void bdrv_attach_child_common_abort(void *opaque
)
2956 BdrvAttachChildCommonState
*s
= opaque
;
2957 BlockDriverState
*bs
= s
->child
->bs
;
2959 GLOBAL_STATE_CODE();
2961 bdrv_graph_wrlock(NULL
);
2962 bdrv_replace_child_noperm(s
->child
, NULL
);
2963 bdrv_graph_wrunlock();
2965 if (bdrv_get_aio_context(bs
) != s
->old_child_ctx
) {
2966 bdrv_try_change_aio_context(bs
, s
->old_child_ctx
, NULL
, &error_abort
);
2969 if (bdrv_child_get_parent_aio_context(s
->child
) != s
->old_parent_ctx
) {
2971 GHashTable
*visited
;
2976 /* No need to visit `child`, because it has been detached already */
2977 visited
= g_hash_table_new(NULL
, NULL
);
2978 ret
= s
->child
->klass
->change_aio_ctx(s
->child
, s
->old_parent_ctx
,
2979 visited
, tran
, &error_abort
);
2980 g_hash_table_destroy(visited
);
2982 /* transaction is supposed to always succeed */
2983 assert(ret
== true);
2988 bdrv_child_free(s
->child
);
2991 static TransactionActionDrv bdrv_attach_child_common_drv
= {
2992 .abort
= bdrv_attach_child_common_abort
,
2997 * Common part of attaching bdrv child to bs or to blk or to job
2999 * Function doesn't update permissions, caller is responsible for this.
3001 * Returns new created child.
3003 * The caller must hold the AioContext lock for @child_bs. Both @parent_bs and
3004 * @child_bs can move to a different AioContext in this function. Callers must
3005 * make sure that their AioContext locking is still correct after this.
3007 static BdrvChild
*bdrv_attach_child_common(BlockDriverState
*child_bs
,
3008 const char *child_name
,
3009 const BdrvChildClass
*child_class
,
3010 BdrvChildRole child_role
,
3011 uint64_t perm
, uint64_t shared_perm
,
3013 Transaction
*tran
, Error
**errp
)
3015 BdrvChild
*new_child
;
3016 AioContext
*parent_ctx
, *new_child_ctx
;
3017 AioContext
*child_ctx
= bdrv_get_aio_context(child_bs
);
3019 assert(child_class
->get_parent_desc
);
3020 GLOBAL_STATE_CODE();
3022 new_child
= g_new(BdrvChild
, 1);
3023 *new_child
= (BdrvChild
) {
3025 .name
= g_strdup(child_name
),
3026 .klass
= child_class
,
3029 .shared_perm
= shared_perm
,
3034 * If the AioContexts don't match, first try to move the subtree of
3035 * child_bs into the AioContext of the new parent. If this doesn't work,
3036 * try moving the parent into the AioContext of child_bs instead.
3038 parent_ctx
= bdrv_child_get_parent_aio_context(new_child
);
3039 if (child_ctx
!= parent_ctx
) {
3040 Error
*local_err
= NULL
;
3041 int ret
= bdrv_try_change_aio_context(child_bs
, parent_ctx
, NULL
,
3044 if (ret
< 0 && child_class
->change_aio_ctx
) {
3045 Transaction
*tran
= tran_new();
3046 GHashTable
*visited
= g_hash_table_new(NULL
, NULL
);
3049 g_hash_table_add(visited
, new_child
);
3050 ret_child
= child_class
->change_aio_ctx(new_child
, child_ctx
,
3051 visited
, tran
, NULL
);
3052 if (ret_child
== true) {
3053 error_free(local_err
);
3056 tran_finalize(tran
, ret_child
== true ? 0 : -1);
3057 g_hash_table_destroy(visited
);
3061 error_propagate(errp
, local_err
);
3062 bdrv_child_free(new_child
);
3067 new_child_ctx
= bdrv_get_aio_context(child_bs
);
3068 if (new_child_ctx
!= child_ctx
) {
3069 aio_context_release(child_ctx
);
3070 aio_context_acquire(new_child_ctx
);
3075 * Let every new BdrvChild start with a drained parent. Inserting the child
3076 * in the graph with bdrv_replace_child_noperm() will undrain it if
3077 * @child_bs is not drained.
3079 * The child was only just created and is not yet visible in global state
3080 * until bdrv_replace_child_noperm() inserts it into the graph, so nobody
3081 * could have sent requests and polling is not necessary.
3083 * Note that this means that the parent isn't fully drained yet, we only
3084 * stop new requests from coming in. This is fine, we don't care about the
3085 * old requests here, they are not for this child. If another place enters a
3086 * drain section for the same parent, but wants it to be fully quiesced, it
3087 * will not run most of the the code in .drained_begin() again (which is not
3088 * a problem, we already did this), but it will still poll until the parent
3089 * is fully quiesced, so it will not be negatively affected either.
3091 bdrv_graph_wrlock(child_bs
);
3092 bdrv_parent_drained_begin_single(new_child
);
3093 bdrv_replace_child_noperm(new_child
, child_bs
);
3094 bdrv_graph_wrunlock();
3096 BdrvAttachChildCommonState
*s
= g_new(BdrvAttachChildCommonState
, 1);
3097 *s
= (BdrvAttachChildCommonState
) {
3099 .old_parent_ctx
= parent_ctx
,
3100 .old_child_ctx
= child_ctx
,
3102 tran_add(tran
, &bdrv_attach_child_common_drv
, s
);
3104 if (new_child_ctx
!= child_ctx
) {
3105 aio_context_release(new_child_ctx
);
3106 aio_context_acquire(child_ctx
);
3113 * Function doesn't update permissions, caller is responsible for this.
3115 * The caller must hold the AioContext lock for @child_bs. Both @parent_bs and
3116 * @child_bs can move to a different AioContext in this function. Callers must
3117 * make sure that their AioContext locking is still correct after this.
3119 static BdrvChild
*bdrv_attach_child_noperm(BlockDriverState
*parent_bs
,
3120 BlockDriverState
*child_bs
,
3121 const char *child_name
,
3122 const BdrvChildClass
*child_class
,
3123 BdrvChildRole child_role
,
3127 uint64_t perm
, shared_perm
;
3129 assert(parent_bs
->drv
);
3130 GLOBAL_STATE_CODE();
3132 if (bdrv_recurse_has_child(child_bs
, parent_bs
)) {
3133 error_setg(errp
, "Making '%s' a %s child of '%s' would create a cycle",
3134 child_bs
->node_name
, child_name
, parent_bs
->node_name
);
3138 bdrv_get_cumulative_perm(parent_bs
, &perm
, &shared_perm
);
3139 bdrv_child_perm(parent_bs
, child_bs
, NULL
, child_role
, NULL
,
3140 perm
, shared_perm
, &perm
, &shared_perm
);
3142 return bdrv_attach_child_common(child_bs
, child_name
, child_class
,
3143 child_role
, perm
, shared_perm
, parent_bs
,
3148 * This function steals the reference to child_bs from the caller.
3149 * That reference is later dropped by bdrv_root_unref_child().
3151 * On failure NULL is returned, errp is set and the reference to
3152 * child_bs is also dropped.
3154 * The caller must hold the AioContext lock @child_bs, but not that of @ctx
3155 * (unless @child_bs is already in @ctx).
3157 BdrvChild
*bdrv_root_attach_child(BlockDriverState
*child_bs
,
3158 const char *child_name
,
3159 const BdrvChildClass
*child_class
,
3160 BdrvChildRole child_role
,
3161 uint64_t perm
, uint64_t shared_perm
,
3162 void *opaque
, Error
**errp
)
3166 Transaction
*tran
= tran_new();
3168 GLOBAL_STATE_CODE();
3170 child
= bdrv_attach_child_common(child_bs
, child_name
, child_class
,
3171 child_role
, perm
, shared_perm
, opaque
,
3178 ret
= bdrv_refresh_perms(child_bs
, tran
, errp
);
3181 tran_finalize(tran
, ret
);
3183 bdrv_unref(child_bs
);
3185 return ret
< 0 ? NULL
: child
;
3189 * This function transfers the reference to child_bs from the caller
3190 * to parent_bs. That reference is later dropped by parent_bs on
3191 * bdrv_close() or if someone calls bdrv_unref_child().
3193 * On failure NULL is returned, errp is set and the reference to
3194 * child_bs is also dropped.
3196 * If @parent_bs and @child_bs are in different AioContexts, the caller must
3197 * hold the AioContext lock for @child_bs, but not for @parent_bs.
3199 BdrvChild
*bdrv_attach_child(BlockDriverState
*parent_bs
,
3200 BlockDriverState
*child_bs
,
3201 const char *child_name
,
3202 const BdrvChildClass
*child_class
,
3203 BdrvChildRole child_role
,
3208 Transaction
*tran
= tran_new();
3210 GLOBAL_STATE_CODE();
3212 child
= bdrv_attach_child_noperm(parent_bs
, child_bs
, child_name
,
3213 child_class
, child_role
, tran
, errp
);
3219 ret
= bdrv_refresh_perms(parent_bs
, tran
, errp
);
3225 tran_finalize(tran
, ret
);
3227 bdrv_unref(child_bs
);
3229 return ret
< 0 ? NULL
: child
;
3232 /* Callers must ensure that child->frozen is false. */
3233 void bdrv_root_unref_child(BdrvChild
*child
)
3235 BlockDriverState
*child_bs
= child
->bs
;
3237 GLOBAL_STATE_CODE();
3238 bdrv_graph_wrlock(NULL
);
3239 bdrv_replace_child_noperm(child
, NULL
);
3240 bdrv_graph_wrunlock();
3241 bdrv_child_free(child
);
3245 * Update permissions for old node. We're just taking a parent away, so
3246 * we're loosening restrictions. Errors of permission update are not
3247 * fatal in this case, ignore them.
3249 bdrv_refresh_perms(child_bs
, NULL
, NULL
);
3252 * When the parent requiring a non-default AioContext is removed, the
3253 * node moves back to the main AioContext
3255 bdrv_try_change_aio_context(child_bs
, qemu_get_aio_context(), NULL
,
3259 bdrv_unref(child_bs
);
3262 typedef struct BdrvSetInheritsFrom
{
3263 BlockDriverState
*bs
;
3264 BlockDriverState
*old_inherits_from
;
3265 } BdrvSetInheritsFrom
;
3267 static void bdrv_set_inherits_from_abort(void *opaque
)
3269 BdrvSetInheritsFrom
*s
= opaque
;
3271 s
->bs
->inherits_from
= s
->old_inherits_from
;
3274 static TransactionActionDrv bdrv_set_inherits_from_drv
= {
3275 .abort
= bdrv_set_inherits_from_abort
,
3279 /* @tran is allowed to be NULL. In this case no rollback is possible */
3280 static void bdrv_set_inherits_from(BlockDriverState
*bs
,
3281 BlockDriverState
*new_inherits_from
,
3285 BdrvSetInheritsFrom
*s
= g_new(BdrvSetInheritsFrom
, 1);
3287 *s
= (BdrvSetInheritsFrom
) {
3289 .old_inherits_from
= bs
->inherits_from
,
3292 tran_add(tran
, &bdrv_set_inherits_from_drv
, s
);
3295 bs
->inherits_from
= new_inherits_from
;
3299 * Clear all inherits_from pointers from children and grandchildren of
3300 * @root that point to @root, where necessary.
3301 * @tran is allowed to be NULL. In this case no rollback is possible
3303 static void bdrv_unset_inherits_from(BlockDriverState
*root
, BdrvChild
*child
,
3308 if (child
->bs
->inherits_from
== root
) {
3310 * Remove inherits_from only when the last reference between root and
3311 * child->bs goes away.
3313 QLIST_FOREACH(c
, &root
->children
, next
) {
3314 if (c
!= child
&& c
->bs
== child
->bs
) {
3319 bdrv_set_inherits_from(child
->bs
, NULL
, tran
);
3323 QLIST_FOREACH(c
, &child
->bs
->children
, next
) {
3324 bdrv_unset_inherits_from(root
, c
, tran
);
3328 /* Callers must ensure that child->frozen is false. */
3329 void bdrv_unref_child(BlockDriverState
*parent
, BdrvChild
*child
)
3331 GLOBAL_STATE_CODE();
3332 if (child
== NULL
) {
3336 bdrv_unset_inherits_from(parent
, child
, NULL
);
3337 bdrv_root_unref_child(child
);
3341 static void bdrv_parent_cb_change_media(BlockDriverState
*bs
, bool load
)
3344 GLOBAL_STATE_CODE();
3345 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
3346 if (c
->klass
->change_media
) {
3347 c
->klass
->change_media(c
, load
);
3352 /* Return true if you can reach parent going through child->inherits_from
3353 * recursively. If parent or child are NULL, return false */
3354 static bool bdrv_inherits_from_recursive(BlockDriverState
*child
,
3355 BlockDriverState
*parent
)
3357 while (child
&& child
!= parent
) {
3358 child
= child
->inherits_from
;
3361 return child
!= NULL
;
3365 * Return the BdrvChildRole for @bs's backing child. bs->backing is
3366 * mostly used for COW backing children (role = COW), but also for
3367 * filtered children (role = FILTERED | PRIMARY).
3369 static BdrvChildRole
bdrv_backing_role(BlockDriverState
*bs
)
3371 if (bs
->drv
&& bs
->drv
->is_filter
) {
3372 return BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
;
3374 return BDRV_CHILD_COW
;
3379 * Sets the bs->backing or bs->file link of a BDS. A new reference is created;
3380 * callers which don't need their own reference any more must call bdrv_unref().
3382 * Function doesn't update permissions, caller is responsible for this.
3384 * The caller must hold the AioContext lock for @child_bs. Both @parent_bs and
3385 * @child_bs can move to a different AioContext in this function. Callers must
3386 * make sure that their AioContext locking is still correct after this.
3388 static int bdrv_set_file_or_backing_noperm(BlockDriverState
*parent_bs
,
3389 BlockDriverState
*child_bs
,
3391 Transaction
*tran
, Error
**errp
)
3393 bool update_inherits_from
=
3394 bdrv_inherits_from_recursive(child_bs
, parent_bs
);
3395 BdrvChild
*child
= is_backing
? parent_bs
->backing
: parent_bs
->file
;
3398 GLOBAL_STATE_CODE();
3400 if (!parent_bs
->drv
) {
3402 * Node without drv is an object without a class :/. TODO: finally fix
3403 * qcow2 driver to never clear bs->drv and implement format corruption
3404 * handling in other way.
3406 error_setg(errp
, "Node corrupted");
3410 if (child
&& child
->frozen
) {
3411 error_setg(errp
, "Cannot change frozen '%s' link from '%s' to '%s'",
3412 child
->name
, parent_bs
->node_name
, child
->bs
->node_name
);
3416 if (is_backing
&& !parent_bs
->drv
->is_filter
&&
3417 !parent_bs
->drv
->supports_backing
)
3419 error_setg(errp
, "Driver '%s' of node '%s' does not support backing "
3420 "files", parent_bs
->drv
->format_name
, parent_bs
->node_name
);
3424 if (parent_bs
->drv
->is_filter
) {
3425 role
= BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
;
3426 } else if (is_backing
) {
3427 role
= BDRV_CHILD_COW
;
3430 * We only can use same role as it is in existing child. We don't have
3431 * infrastructure to determine role of file child in generic way
3434 error_setg(errp
, "Cannot set file child to format node without "
3442 bdrv_unset_inherits_from(parent_bs
, child
, tran
);
3443 bdrv_remove_child(child
, tran
);
3450 child
= bdrv_attach_child_noperm(parent_bs
, child_bs
,
3451 is_backing
? "backing" : "file",
3452 &child_of_bds
, role
,
3460 * If inherits_from pointed recursively to bs then let's update it to
3461 * point directly to bs (else it will become NULL).
3463 if (update_inherits_from
) {
3464 bdrv_set_inherits_from(child_bs
, parent_bs
, tran
);
3468 bdrv_graph_rdlock_main_loop();
3469 bdrv_refresh_limits(parent_bs
, tran
, NULL
);
3470 bdrv_graph_rdunlock_main_loop();
3476 * The caller must hold the AioContext lock for @backing_hd. Both @bs and
3477 * @backing_hd can move to a different AioContext in this function. Callers must
3478 * make sure that their AioContext locking is still correct after this.
3480 static int bdrv_set_backing_noperm(BlockDriverState
*bs
,
3481 BlockDriverState
*backing_hd
,
3482 Transaction
*tran
, Error
**errp
)
3484 GLOBAL_STATE_CODE();
3485 return bdrv_set_file_or_backing_noperm(bs
, backing_hd
, true, tran
, errp
);
3488 int bdrv_set_backing_hd_drained(BlockDriverState
*bs
,
3489 BlockDriverState
*backing_hd
,
3493 Transaction
*tran
= tran_new();
3495 GLOBAL_STATE_CODE();
3496 assert(bs
->quiesce_counter
> 0);
3498 ret
= bdrv_set_backing_noperm(bs
, backing_hd
, tran
, errp
);
3503 ret
= bdrv_refresh_perms(bs
, tran
, errp
);
3505 tran_finalize(tran
, ret
);
3509 int bdrv_set_backing_hd(BlockDriverState
*bs
, BlockDriverState
*backing_hd
,
3513 GLOBAL_STATE_CODE();
3515 bdrv_drained_begin(bs
);
3516 ret
= bdrv_set_backing_hd_drained(bs
, backing_hd
, errp
);
3517 bdrv_drained_end(bs
);
3523 * Opens the backing file for a BlockDriverState if not yet open
3525 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
3526 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
3527 * itself, all options starting with "${bdref_key}." are considered part of the
3530 * The caller must hold the main AioContext lock.
3532 * TODO Can this be unified with bdrv_open_image()?
3534 int bdrv_open_backing_file(BlockDriverState
*bs
, QDict
*parent_options
,
3535 const char *bdref_key
, Error
**errp
)
3537 char *backing_filename
= NULL
;
3538 char *bdref_key_dot
;
3539 const char *reference
= NULL
;
3541 bool implicit_backing
= false;
3542 BlockDriverState
*backing_hd
;
3543 AioContext
*backing_hd_ctx
;
3545 QDict
*tmp_parent_options
= NULL
;
3546 Error
*local_err
= NULL
;
3548 GLOBAL_STATE_CODE();
3550 if (bs
->backing
!= NULL
) {
3554 /* NULL means an empty set of options */
3555 if (parent_options
== NULL
) {
3556 tmp_parent_options
= qdict_new();
3557 parent_options
= tmp_parent_options
;
3560 bs
->open_flags
&= ~BDRV_O_NO_BACKING
;
3562 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
3563 qdict_extract_subqdict(parent_options
, &options
, bdref_key_dot
);
3564 g_free(bdref_key_dot
);
3567 * Caution: while qdict_get_try_str() is fine, getting non-string
3568 * types would require more care. When @parent_options come from
3569 * -blockdev or blockdev_add, its members are typed according to
3570 * the QAPI schema, but when they come from -drive, they're all
3573 reference
= qdict_get_try_str(parent_options
, bdref_key
);
3574 if (reference
|| qdict_haskey(options
, "file.filename")) {
3575 /* keep backing_filename NULL */
3576 } else if (bs
->backing_file
[0] == '\0' && qdict_size(options
) == 0) {
3577 qobject_unref(options
);
3580 if (qdict_size(options
) == 0) {
3581 /* If the user specifies options that do not modify the
3582 * backing file's behavior, we might still consider it the
3583 * implicit backing file. But it's easier this way, and
3584 * just specifying some of the backing BDS's options is
3585 * only possible with -drive anyway (otherwise the QAPI
3586 * schema forces the user to specify everything). */
3587 implicit_backing
= !strcmp(bs
->auto_backing_file
, bs
->backing_file
);
3590 backing_filename
= bdrv_get_full_backing_filename(bs
, &local_err
);
3593 error_propagate(errp
, local_err
);
3594 qobject_unref(options
);
3599 if (!bs
->drv
|| !bs
->drv
->supports_backing
) {
3601 error_setg(errp
, "Driver doesn't support backing files");
3602 qobject_unref(options
);
3607 bs
->backing_format
[0] != '\0' && !qdict_haskey(options
, "driver")) {
3608 qdict_put_str(options
, "driver", bs
->backing_format
);
3611 backing_hd
= bdrv_open_inherit(backing_filename
, reference
, options
, 0, bs
,
3612 &child_of_bds
, bdrv_backing_role(bs
), errp
);
3614 bs
->open_flags
|= BDRV_O_NO_BACKING
;
3615 error_prepend(errp
, "Could not open backing file: ");
3620 if (implicit_backing
) {
3621 bdrv_refresh_filename(backing_hd
);
3622 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
3623 backing_hd
->filename
);
3626 /* Hook up the backing file link; drop our reference, bs owns the
3627 * backing_hd reference now */
3628 backing_hd_ctx
= bdrv_get_aio_context(backing_hd
);
3629 aio_context_acquire(backing_hd_ctx
);
3630 ret
= bdrv_set_backing_hd(bs
, backing_hd
, errp
);
3631 bdrv_unref(backing_hd
);
3632 aio_context_release(backing_hd_ctx
);
3638 qdict_del(parent_options
, bdref_key
);
3641 g_free(backing_filename
);
3642 qobject_unref(tmp_parent_options
);
3646 static BlockDriverState
*
3647 bdrv_open_child_bs(const char *filename
, QDict
*options
, const char *bdref_key
,
3648 BlockDriverState
*parent
, const BdrvChildClass
*child_class
,
3649 BdrvChildRole child_role
, bool allow_none
, Error
**errp
)
3651 BlockDriverState
*bs
= NULL
;
3652 QDict
*image_options
;
3653 char *bdref_key_dot
;
3654 const char *reference
;
3656 assert(child_class
!= NULL
);
3658 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
3659 qdict_extract_subqdict(options
, &image_options
, bdref_key_dot
);
3660 g_free(bdref_key_dot
);
3663 * Caution: while qdict_get_try_str() is fine, getting non-string
3664 * types would require more care. When @options come from
3665 * -blockdev or blockdev_add, its members are typed according to
3666 * the QAPI schema, but when they come from -drive, they're all
3669 reference
= qdict_get_try_str(options
, bdref_key
);
3670 if (!filename
&& !reference
&& !qdict_size(image_options
)) {
3672 error_setg(errp
, "A block device must be specified for \"%s\"",
3675 qobject_unref(image_options
);
3679 bs
= bdrv_open_inherit(filename
, reference
, image_options
, 0,
3680 parent
, child_class
, child_role
, errp
);
3686 qdict_del(options
, bdref_key
);
3691 * Opens a disk image whose options are given as BlockdevRef in another block
3694 * If allow_none is true, no image will be opened if filename is false and no
3695 * BlockdevRef is given. NULL will be returned, but errp remains unset.
3697 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
3698 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
3699 * itself, all options starting with "${bdref_key}." are considered part of the
3702 * The BlockdevRef will be removed from the options QDict.
3704 * The caller must hold the lock of the main AioContext and no other AioContext.
3705 * @parent can move to a different AioContext in this function. Callers must
3706 * make sure that their AioContext locking is still correct after this.
3708 BdrvChild
*bdrv_open_child(const char *filename
,
3709 QDict
*options
, const char *bdref_key
,
3710 BlockDriverState
*parent
,
3711 const BdrvChildClass
*child_class
,
3712 BdrvChildRole child_role
,
3713 bool allow_none
, Error
**errp
)
3715 BlockDriverState
*bs
;
3719 GLOBAL_STATE_CODE();
3721 bs
= bdrv_open_child_bs(filename
, options
, bdref_key
, parent
, child_class
,
3722 child_role
, allow_none
, errp
);
3727 ctx
= bdrv_get_aio_context(bs
);
3728 aio_context_acquire(ctx
);
3729 child
= bdrv_attach_child(parent
, bs
, bdref_key
, child_class
, child_role
,
3731 aio_context_release(ctx
);
3737 * Wrapper on bdrv_open_child() for most popular case: open primary child of bs.
3739 * The caller must hold the lock of the main AioContext and no other AioContext.
3740 * @parent can move to a different AioContext in this function. Callers must
3741 * make sure that their AioContext locking is still correct after this.
3743 int bdrv_open_file_child(const char *filename
,
3744 QDict
*options
, const char *bdref_key
,
3745 BlockDriverState
*parent
, Error
**errp
)
3749 /* commit_top and mirror_top don't use this function */
3750 assert(!parent
->drv
->filtered_child_is_backing
);
3751 role
= parent
->drv
->is_filter
?
3752 (BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
) : BDRV_CHILD_IMAGE
;
3754 if (!bdrv_open_child(filename
, options
, bdref_key
, parent
,
3755 &child_of_bds
, role
, false, errp
))
3764 * TODO Future callers may need to specify parent/child_class in order for
3765 * option inheritance to work. Existing callers use it for the root node.
3767 BlockDriverState
*bdrv_open_blockdev_ref(BlockdevRef
*ref
, Error
**errp
)
3769 BlockDriverState
*bs
= NULL
;
3770 QObject
*obj
= NULL
;
3771 QDict
*qdict
= NULL
;
3772 const char *reference
= NULL
;
3775 GLOBAL_STATE_CODE();
3777 if (ref
->type
== QTYPE_QSTRING
) {
3778 reference
= ref
->u
.reference
;
3780 BlockdevOptions
*options
= &ref
->u
.definition
;
3781 assert(ref
->type
== QTYPE_QDICT
);
3783 v
= qobject_output_visitor_new(&obj
);
3784 visit_type_BlockdevOptions(v
, NULL
, &options
, &error_abort
);
3785 visit_complete(v
, &obj
);
3787 qdict
= qobject_to(QDict
, obj
);
3788 qdict_flatten(qdict
);
3790 /* bdrv_open_inherit() defaults to the values in bdrv_flags (for
3791 * compatibility with other callers) rather than what we want as the
3792 * real defaults. Apply the defaults here instead. */
3793 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_DIRECT
, "off");
3794 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_NO_FLUSH
, "off");
3795 qdict_set_default_str(qdict
, BDRV_OPT_READ_ONLY
, "off");
3796 qdict_set_default_str(qdict
, BDRV_OPT_AUTO_READ_ONLY
, "off");
3800 bs
= bdrv_open_inherit(NULL
, reference
, qdict
, 0, NULL
, NULL
, 0, errp
);
3807 static BlockDriverState
*bdrv_append_temp_snapshot(BlockDriverState
*bs
,
3809 QDict
*snapshot_options
,
3812 g_autofree
char *tmp_filename
= NULL
;
3814 QemuOpts
*opts
= NULL
;
3815 BlockDriverState
*bs_snapshot
= NULL
;
3816 AioContext
*ctx
= bdrv_get_aio_context(bs
);
3819 GLOBAL_STATE_CODE();
3821 /* if snapshot, we create a temporary backing file and open it
3822 instead of opening 'filename' directly */
3824 /* Get the required size from the image */
3825 aio_context_acquire(ctx
);
3826 total_size
= bdrv_getlength(bs
);
3827 aio_context_release(ctx
);
3829 if (total_size
< 0) {
3830 error_setg_errno(errp
, -total_size
, "Could not get image size");
3834 /* Create the temporary image */
3835 tmp_filename
= create_tmp_file(errp
);
3836 if (!tmp_filename
) {
3840 opts
= qemu_opts_create(bdrv_qcow2
.create_opts
, NULL
, 0,
3842 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, total_size
, &error_abort
);
3843 ret
= bdrv_create(&bdrv_qcow2
, tmp_filename
, opts
, errp
);
3844 qemu_opts_del(opts
);
3846 error_prepend(errp
, "Could not create temporary overlay '%s': ",
3851 /* Prepare options QDict for the temporary file */
3852 qdict_put_str(snapshot_options
, "file.driver", "file");
3853 qdict_put_str(snapshot_options
, "file.filename", tmp_filename
);
3854 qdict_put_str(snapshot_options
, "driver", "qcow2");
3856 bs_snapshot
= bdrv_open(NULL
, NULL
, snapshot_options
, flags
, errp
);
3857 snapshot_options
= NULL
;
3862 aio_context_acquire(ctx
);
3863 ret
= bdrv_append(bs_snapshot
, bs
, errp
);
3864 aio_context_release(ctx
);
3872 qobject_unref(snapshot_options
);
3877 * Opens a disk image (raw, qcow2, vmdk, ...)
3879 * options is a QDict of options to pass to the block drivers, or NULL for an
3880 * empty set of options. The reference to the QDict belongs to the block layer
3881 * after the call (even on failure), so if the caller intends to reuse the
3882 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
3884 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
3885 * If it is not NULL, the referenced BDS will be reused.
3887 * The reference parameter may be used to specify an existing block device which
3888 * should be opened. If specified, neither options nor a filename may be given,
3889 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
3891 * The caller must always hold the main AioContext lock.
3893 static BlockDriverState
* no_coroutine_fn
3894 bdrv_open_inherit(const char *filename
, const char *reference
, QDict
*options
,
3895 int flags
, BlockDriverState
*parent
,
3896 const BdrvChildClass
*child_class
, BdrvChildRole child_role
,
3900 BlockBackend
*file
= NULL
;
3901 BlockDriverState
*bs
;
3902 BlockDriver
*drv
= NULL
;
3904 const char *drvname
;
3905 const char *backing
;
3906 Error
*local_err
= NULL
;
3907 QDict
*snapshot_options
= NULL
;
3908 int snapshot_flags
= 0;
3909 AioContext
*ctx
= qemu_get_aio_context();
3911 assert(!child_class
|| !flags
);
3912 assert(!child_class
== !parent
);
3913 GLOBAL_STATE_CODE();
3914 assert(!qemu_in_coroutine());
3917 bool options_non_empty
= options
? qdict_size(options
) : false;
3918 qobject_unref(options
);
3920 if (filename
|| options_non_empty
) {
3921 error_setg(errp
, "Cannot reference an existing block device with "
3922 "additional options or a new filename");
3926 bs
= bdrv_lookup_bs(reference
, reference
, errp
);
3937 /* NULL means an empty set of options */
3938 if (options
== NULL
) {
3939 options
= qdict_new();
3942 /* json: syntax counts as explicit options, as if in the QDict */
3943 parse_json_protocol(options
, &filename
, &local_err
);
3948 bs
->explicit_options
= qdict_clone_shallow(options
);
3951 bool parent_is_format
;
3954 parent_is_format
= parent
->drv
->is_format
;
3957 * parent->drv is not set yet because this node is opened for
3958 * (potential) format probing. That means that @parent is going
3959 * to be a format node.
3961 parent_is_format
= true;
3964 bs
->inherits_from
= parent
;
3965 child_class
->inherit_options(child_role
, parent_is_format
,
3967 parent
->open_flags
, parent
->options
);
3970 ret
= bdrv_fill_options(&options
, filename
, &flags
, &local_err
);
3976 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
3977 * Caution: getting a boolean member of @options requires care.
3978 * When @options come from -blockdev or blockdev_add, members are
3979 * typed according to the QAPI schema, but when they come from
3980 * -drive, they're all QString.
3982 if (g_strcmp0(qdict_get_try_str(options
, BDRV_OPT_READ_ONLY
), "on") &&
3983 !qdict_get_try_bool(options
, BDRV_OPT_READ_ONLY
, false)) {
3984 flags
|= (BDRV_O_RDWR
| BDRV_O_ALLOW_RDWR
);
3986 flags
&= ~BDRV_O_RDWR
;
3989 if (flags
& BDRV_O_SNAPSHOT
) {
3990 snapshot_options
= qdict_new();
3991 bdrv_temp_snapshot_options(&snapshot_flags
, snapshot_options
,
3993 /* Let bdrv_backing_options() override "read-only" */
3994 qdict_del(options
, BDRV_OPT_READ_ONLY
);
3995 bdrv_inherited_options(BDRV_CHILD_COW
, true,
3996 &flags
, options
, flags
, options
);
3999 bs
->open_flags
= flags
;
4000 bs
->options
= options
;
4001 options
= qdict_clone_shallow(options
);
4003 /* Find the right image format driver */
4004 /* See cautionary note on accessing @options above */
4005 drvname
= qdict_get_try_str(options
, "driver");
4007 drv
= bdrv_find_format(drvname
);
4009 error_setg(errp
, "Unknown driver: '%s'", drvname
);
4014 assert(drvname
|| !(flags
& BDRV_O_PROTOCOL
));
4016 /* See cautionary note on accessing @options above */
4017 backing
= qdict_get_try_str(options
, "backing");
4018 if (qobject_to(QNull
, qdict_get(options
, "backing")) != NULL
||
4019 (backing
&& *backing
== '\0'))
4022 warn_report("Use of \"backing\": \"\" is deprecated; "
4023 "use \"backing\": null instead");
4025 flags
|= BDRV_O_NO_BACKING
;
4026 qdict_del(bs
->explicit_options
, "backing");
4027 qdict_del(bs
->options
, "backing");
4028 qdict_del(options
, "backing");
4031 /* Open image file without format layer. This BlockBackend is only used for
4032 * probing, the block drivers will do their own bdrv_open_child() for the
4033 * same BDS, which is why we put the node name back into options. */
4034 if ((flags
& BDRV_O_PROTOCOL
) == 0) {
4035 BlockDriverState
*file_bs
;
4037 file_bs
= bdrv_open_child_bs(filename
, options
, "file", bs
,
4038 &child_of_bds
, BDRV_CHILD_IMAGE
,
4043 if (file_bs
!= NULL
) {
4044 /* Not requesting BLK_PERM_CONSISTENT_READ because we're only
4045 * looking at the header to guess the image format. This works even
4046 * in cases where a guest would not see a consistent state. */
4047 ctx
= bdrv_get_aio_context(file_bs
);
4048 aio_context_acquire(ctx
);
4049 file
= blk_new(ctx
, 0, BLK_PERM_ALL
);
4050 blk_insert_bs(file
, file_bs
, &local_err
);
4051 bdrv_unref(file_bs
);
4052 aio_context_release(ctx
);
4058 qdict_put_str(options
, "file", bdrv_get_node_name(file_bs
));
4062 /* Image format probing */
4065 ret
= find_image_format(file
, filename
, &drv
, &local_err
);
4070 * This option update would logically belong in bdrv_fill_options(),
4071 * but we first need to open bs->file for the probing to work, while
4072 * opening bs->file already requires the (mostly) final set of options
4073 * so that cache mode etc. can be inherited.
4075 * Adding the driver later is somewhat ugly, but it's not an option
4076 * that would ever be inherited, so it's correct. We just need to make
4077 * sure to update both bs->options (which has the full effective
4078 * options for bs) and options (which has file.* already removed).
4080 qdict_put_str(bs
->options
, "driver", drv
->format_name
);
4081 qdict_put_str(options
, "driver", drv
->format_name
);
4083 error_setg(errp
, "Must specify either driver or file");
4087 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
4088 assert(!!(flags
& BDRV_O_PROTOCOL
) == !!drv
->bdrv_file_open
);
4089 /* file must be NULL if a protocol BDS is about to be created
4090 * (the inverse results in an error message from bdrv_open_common()) */
4091 assert(!(flags
& BDRV_O_PROTOCOL
) || !file
);
4093 /* Open the image */
4094 ret
= bdrv_open_common(bs
, file
, options
, &local_err
);
4099 /* The AioContext could have changed during bdrv_open_common() */
4100 ctx
= bdrv_get_aio_context(bs
);
4103 aio_context_acquire(ctx
);
4105 aio_context_release(ctx
);
4109 /* If there is a backing file, use it */
4110 if ((flags
& BDRV_O_NO_BACKING
) == 0) {
4111 ret
= bdrv_open_backing_file(bs
, options
, "backing", &local_err
);
4113 goto close_and_fail
;
4117 /* Remove all children options and references
4118 * from bs->options and bs->explicit_options */
4119 QLIST_FOREACH(child
, &bs
->children
, next
) {
4120 char *child_key_dot
;
4121 child_key_dot
= g_strdup_printf("%s.", child
->name
);
4122 qdict_extract_subqdict(bs
->explicit_options
, NULL
, child_key_dot
);
4123 qdict_extract_subqdict(bs
->options
, NULL
, child_key_dot
);
4124 qdict_del(bs
->explicit_options
, child
->name
);
4125 qdict_del(bs
->options
, child
->name
);
4126 g_free(child_key_dot
);
4129 /* Check if any unknown options were used */
4130 if (qdict_size(options
) != 0) {
4131 const QDictEntry
*entry
= qdict_first(options
);
4132 if (flags
& BDRV_O_PROTOCOL
) {
4133 error_setg(errp
, "Block protocol '%s' doesn't support the option "
4134 "'%s'", drv
->format_name
, entry
->key
);
4137 "Block format '%s' does not support the option '%s'",
4138 drv
->format_name
, entry
->key
);
4141 goto close_and_fail
;
4144 bdrv_parent_cb_change_media(bs
, true);
4146 qobject_unref(options
);
4149 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
4150 * temporary snapshot afterwards. */
4151 if (snapshot_flags
) {
4152 BlockDriverState
*snapshot_bs
;
4153 snapshot_bs
= bdrv_append_temp_snapshot(bs
, snapshot_flags
,
4154 snapshot_options
, &local_err
);
4155 snapshot_options
= NULL
;
4157 goto close_and_fail
;
4159 /* We are not going to return bs but the overlay on top of it
4160 * (snapshot_bs); thus, we have to drop the strong reference to bs
4161 * (which we obtained by calling bdrv_new()). bs will not be deleted,
4162 * though, because the overlay still has a reference to it. */
4163 aio_context_acquire(ctx
);
4165 aio_context_release(ctx
);
4172 aio_context_acquire(ctx
);
4174 qobject_unref(snapshot_options
);
4175 qobject_unref(bs
->explicit_options
);
4176 qobject_unref(bs
->options
);
4177 qobject_unref(options
);
4179 bs
->explicit_options
= NULL
;
4181 aio_context_release(ctx
);
4182 error_propagate(errp
, local_err
);
4186 aio_context_acquire(ctx
);
4188 aio_context_release(ctx
);
4189 qobject_unref(snapshot_options
);
4190 qobject_unref(options
);
4191 error_propagate(errp
, local_err
);
4195 /* The caller must always hold the main AioContext lock. */
4196 BlockDriverState
*bdrv_open(const char *filename
, const char *reference
,
4197 QDict
*options
, int flags
, Error
**errp
)
4199 GLOBAL_STATE_CODE();
4201 return bdrv_open_inherit(filename
, reference
, options
, flags
, NULL
,
4205 /* Return true if the NULL-terminated @list contains @str */
4206 static bool is_str_in_list(const char *str
, const char *const *list
)
4210 for (i
= 0; list
[i
] != NULL
; i
++) {
4211 if (!strcmp(str
, list
[i
])) {
4220 * Check that every option set in @bs->options is also set in
4223 * Options listed in the common_options list and in
4224 * @bs->drv->mutable_opts are skipped.
4226 * Return 0 on success, otherwise return -EINVAL and set @errp.
4228 static int bdrv_reset_options_allowed(BlockDriverState
*bs
,
4229 const QDict
*new_opts
, Error
**errp
)
4231 const QDictEntry
*e
;
4232 /* These options are common to all block drivers and are handled
4233 * in bdrv_reopen_prepare() so they can be left out of @new_opts */
4234 const char *const common_options
[] = {
4235 "node-name", "discard", "cache.direct", "cache.no-flush",
4236 "read-only", "auto-read-only", "detect-zeroes", NULL
4239 for (e
= qdict_first(bs
->options
); e
; e
= qdict_next(bs
->options
, e
)) {
4240 if (!qdict_haskey(new_opts
, e
->key
) &&
4241 !is_str_in_list(e
->key
, common_options
) &&
4242 !is_str_in_list(e
->key
, bs
->drv
->mutable_opts
)) {
4243 error_setg(errp
, "Option '%s' cannot be reset "
4244 "to its default value", e
->key
);
4253 * Returns true if @child can be reached recursively from @bs
4255 static bool bdrv_recurse_has_child(BlockDriverState
*bs
,
4256 BlockDriverState
*child
)
4264 QLIST_FOREACH(c
, &bs
->children
, next
) {
4265 if (bdrv_recurse_has_child(c
->bs
, child
)) {
4274 * Adds a BlockDriverState to a simple queue for an atomic, transactional
4275 * reopen of multiple devices.
4277 * bs_queue can either be an existing BlockReopenQueue that has had QTAILQ_INIT
4278 * already performed, or alternatively may be NULL a new BlockReopenQueue will
4279 * be created and initialized. This newly created BlockReopenQueue should be
4280 * passed back in for subsequent calls that are intended to be of the same
4283 * bs is the BlockDriverState to add to the reopen queue.
4285 * options contains the changed options for the associated bs
4286 * (the BlockReopenQueue takes ownership)
4288 * flags contains the open flags for the associated bs
4290 * returns a pointer to bs_queue, which is either the newly allocated
4291 * bs_queue, or the existing bs_queue being used.
4293 * bs is drained here and undrained by bdrv_reopen_queue_free().
4295 * To be called with bs->aio_context locked.
4297 static BlockReopenQueue
*bdrv_reopen_queue_child(BlockReopenQueue
*bs_queue
,
4298 BlockDriverState
*bs
,
4300 const BdrvChildClass
*klass
,
4302 bool parent_is_format
,
4303 QDict
*parent_options
,
4309 BlockReopenQueueEntry
*bs_entry
;
4311 QDict
*old_options
, *explicit_options
, *options_copy
;
4315 GLOBAL_STATE_CODE();
4317 bdrv_drained_begin(bs
);
4319 if (bs_queue
== NULL
) {
4320 bs_queue
= g_new0(BlockReopenQueue
, 1);
4321 QTAILQ_INIT(bs_queue
);
4325 options
= qdict_new();
4328 /* Check if this BlockDriverState is already in the queue */
4329 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4330 if (bs
== bs_entry
->state
.bs
) {
4336 * Precedence of options:
4337 * 1. Explicitly passed in options (highest)
4338 * 2. Retained from explicitly set options of bs
4339 * 3. Inherited from parent node
4340 * 4. Retained from effective options of bs
4343 /* Old explicitly set values (don't overwrite by inherited value) */
4344 if (bs_entry
|| keep_old_opts
) {
4345 old_options
= qdict_clone_shallow(bs_entry
?
4346 bs_entry
->state
.explicit_options
:
4347 bs
->explicit_options
);
4348 bdrv_join_options(bs
, options
, old_options
);
4349 qobject_unref(old_options
);
4352 explicit_options
= qdict_clone_shallow(options
);
4354 /* Inherit from parent node */
4355 if (parent_options
) {
4357 klass
->inherit_options(role
, parent_is_format
, &flags
, options
,
4358 parent_flags
, parent_options
);
4360 flags
= bdrv_get_flags(bs
);
4363 if (keep_old_opts
) {
4364 /* Old values are used for options that aren't set yet */
4365 old_options
= qdict_clone_shallow(bs
->options
);
4366 bdrv_join_options(bs
, options
, old_options
);
4367 qobject_unref(old_options
);
4370 /* We have the final set of options so let's update the flags */
4371 options_copy
= qdict_clone_shallow(options
);
4372 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
4373 qemu_opts_absorb_qdict(opts
, options_copy
, NULL
);
4374 update_flags_from_options(&flags
, opts
);
4375 qemu_opts_del(opts
);
4376 qobject_unref(options_copy
);
4378 /* bdrv_open_inherit() sets and clears some additional flags internally */
4379 flags
&= ~BDRV_O_PROTOCOL
;
4380 if (flags
& BDRV_O_RDWR
) {
4381 flags
|= BDRV_O_ALLOW_RDWR
;
4385 bs_entry
= g_new0(BlockReopenQueueEntry
, 1);
4386 QTAILQ_INSERT_TAIL(bs_queue
, bs_entry
, entry
);
4388 qobject_unref(bs_entry
->state
.options
);
4389 qobject_unref(bs_entry
->state
.explicit_options
);
4392 bs_entry
->state
.bs
= bs
;
4393 bs_entry
->state
.options
= options
;
4394 bs_entry
->state
.explicit_options
= explicit_options
;
4395 bs_entry
->state
.flags
= flags
;
4398 * If keep_old_opts is false then it means that unspecified
4399 * options must be reset to their original value. We don't allow
4400 * resetting 'backing' but we need to know if the option is
4401 * missing in order to decide if we have to return an error.
4403 if (!keep_old_opts
) {
4404 bs_entry
->state
.backing_missing
=
4405 !qdict_haskey(options
, "backing") &&
4406 !qdict_haskey(options
, "backing.driver");
4409 QLIST_FOREACH(child
, &bs
->children
, next
) {
4410 QDict
*new_child_options
= NULL
;
4411 bool child_keep_old
= keep_old_opts
;
4413 /* reopen can only change the options of block devices that were
4414 * implicitly created and inherited options. For other (referenced)
4415 * block devices, a syntax like "backing.foo" results in an error. */
4416 if (child
->bs
->inherits_from
!= bs
) {
4420 /* Check if the options contain a child reference */
4421 if (qdict_haskey(options
, child
->name
)) {
4422 const char *childref
= qdict_get_try_str(options
, child
->name
);
4424 * The current child must not be reopened if the child
4425 * reference is null or points to a different node.
4427 if (g_strcmp0(childref
, child
->bs
->node_name
)) {
4431 * If the child reference points to the current child then
4432 * reopen it with its existing set of options (note that
4433 * it can still inherit new options from the parent).
4435 child_keep_old
= true;
4437 /* Extract child options ("child-name.*") */
4438 char *child_key_dot
= g_strdup_printf("%s.", child
->name
);
4439 qdict_extract_subqdict(explicit_options
, NULL
, child_key_dot
);
4440 qdict_extract_subqdict(options
, &new_child_options
, child_key_dot
);
4441 g_free(child_key_dot
);
4444 bdrv_reopen_queue_child(bs_queue
, child
->bs
, new_child_options
,
4445 child
->klass
, child
->role
, bs
->drv
->is_format
,
4446 options
, flags
, child_keep_old
);
4452 /* To be called with bs->aio_context locked */
4453 BlockReopenQueue
*bdrv_reopen_queue(BlockReopenQueue
*bs_queue
,
4454 BlockDriverState
*bs
,
4455 QDict
*options
, bool keep_old_opts
)
4457 GLOBAL_STATE_CODE();
4459 return bdrv_reopen_queue_child(bs_queue
, bs
, options
, NULL
, 0, false,
4460 NULL
, 0, keep_old_opts
);
4463 void bdrv_reopen_queue_free(BlockReopenQueue
*bs_queue
)
4465 GLOBAL_STATE_CODE();
4467 BlockReopenQueueEntry
*bs_entry
, *next
;
4468 QTAILQ_FOREACH_SAFE(bs_entry
, bs_queue
, entry
, next
) {
4469 AioContext
*ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4471 aio_context_acquire(ctx
);
4472 bdrv_drained_end(bs_entry
->state
.bs
);
4473 aio_context_release(ctx
);
4475 qobject_unref(bs_entry
->state
.explicit_options
);
4476 qobject_unref(bs_entry
->state
.options
);
4484 * Reopen multiple BlockDriverStates atomically & transactionally.
4486 * The queue passed in (bs_queue) must have been built up previous
4487 * via bdrv_reopen_queue().
4489 * Reopens all BDS specified in the queue, with the appropriate
4490 * flags. All devices are prepared for reopen, and failure of any
4491 * device will cause all device changes to be abandoned, and intermediate
4494 * If all devices prepare successfully, then the changes are committed
4497 * All affected nodes must be drained between bdrv_reopen_queue() and
4498 * bdrv_reopen_multiple().
4500 * To be called from the main thread, with all other AioContexts unlocked.
4502 int bdrv_reopen_multiple(BlockReopenQueue
*bs_queue
, Error
**errp
)
4505 BlockReopenQueueEntry
*bs_entry
, *next
;
4507 Transaction
*tran
= tran_new();
4508 g_autoptr(GSList
) refresh_list
= NULL
;
4510 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
4511 assert(bs_queue
!= NULL
);
4512 GLOBAL_STATE_CODE();
4514 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4515 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4516 aio_context_acquire(ctx
);
4517 ret
= bdrv_flush(bs_entry
->state
.bs
);
4518 aio_context_release(ctx
);
4520 error_setg_errno(errp
, -ret
, "Error flushing drive");
4525 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4526 assert(bs_entry
->state
.bs
->quiesce_counter
> 0);
4527 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4528 aio_context_acquire(ctx
);
4529 ret
= bdrv_reopen_prepare(&bs_entry
->state
, bs_queue
, tran
, errp
);
4530 aio_context_release(ctx
);
4534 bs_entry
->prepared
= true;
4537 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4538 BDRVReopenState
*state
= &bs_entry
->state
;
4540 refresh_list
= g_slist_prepend(refresh_list
, state
->bs
);
4541 if (state
->old_backing_bs
) {
4542 refresh_list
= g_slist_prepend(refresh_list
, state
->old_backing_bs
);
4544 if (state
->old_file_bs
) {
4545 refresh_list
= g_slist_prepend(refresh_list
, state
->old_file_bs
);
4550 * Note that file-posix driver rely on permission update done during reopen
4551 * (even if no permission changed), because it wants "new" permissions for
4552 * reconfiguring the fd and that's why it does it in raw_check_perm(), not
4553 * in raw_reopen_prepare() which is called with "old" permissions.
4555 ret
= bdrv_list_refresh_perms(refresh_list
, bs_queue
, tran
, errp
);
4561 * If we reach this point, we have success and just need to apply the
4564 * Reverse order is used to comfort qcow2 driver: on commit it need to write
4565 * IN_USE flag to the image, to mark bitmaps in the image as invalid. But
4566 * children are usually goes after parents in reopen-queue, so go from last
4569 QTAILQ_FOREACH_REVERSE(bs_entry
, bs_queue
, entry
) {
4570 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4571 aio_context_acquire(ctx
);
4572 bdrv_reopen_commit(&bs_entry
->state
);
4573 aio_context_release(ctx
);
4578 QTAILQ_FOREACH_REVERSE(bs_entry
, bs_queue
, entry
) {
4579 BlockDriverState
*bs
= bs_entry
->state
.bs
;
4581 if (bs
->drv
->bdrv_reopen_commit_post
) {
4582 ctx
= bdrv_get_aio_context(bs
);
4583 aio_context_acquire(ctx
);
4584 bs
->drv
->bdrv_reopen_commit_post(&bs_entry
->state
);
4585 aio_context_release(ctx
);
4594 QTAILQ_FOREACH_SAFE(bs_entry
, bs_queue
, entry
, next
) {
4595 if (bs_entry
->prepared
) {
4596 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4597 aio_context_acquire(ctx
);
4598 bdrv_reopen_abort(&bs_entry
->state
);
4599 aio_context_release(ctx
);
4604 bdrv_reopen_queue_free(bs_queue
);
4609 int bdrv_reopen(BlockDriverState
*bs
, QDict
*opts
, bool keep_old_opts
,
4612 AioContext
*ctx
= bdrv_get_aio_context(bs
);
4613 BlockReopenQueue
*queue
;
4616 GLOBAL_STATE_CODE();
4618 queue
= bdrv_reopen_queue(NULL
, bs
, opts
, keep_old_opts
);
4620 if (ctx
!= qemu_get_aio_context()) {
4621 aio_context_release(ctx
);
4623 ret
= bdrv_reopen_multiple(queue
, errp
);
4625 if (ctx
!= qemu_get_aio_context()) {
4626 aio_context_acquire(ctx
);
4632 int bdrv_reopen_set_read_only(BlockDriverState
*bs
, bool read_only
,
4635 QDict
*opts
= qdict_new();
4637 GLOBAL_STATE_CODE();
4639 qdict_put_bool(opts
, BDRV_OPT_READ_ONLY
, read_only
);
4641 return bdrv_reopen(bs
, opts
, true, errp
);
4645 * Take a BDRVReopenState and check if the value of 'backing' in the
4646 * reopen_state->options QDict is valid or not.
4648 * If 'backing' is missing from the QDict then return 0.
4650 * If 'backing' contains the node name of the backing file of
4651 * reopen_state->bs then return 0.
4653 * If 'backing' contains a different node name (or is null) then check
4654 * whether the current backing file can be replaced with the new one.
4655 * If that's the case then reopen_state->replace_backing_bs is set to
4656 * true and reopen_state->new_backing_bs contains a pointer to the new
4657 * backing BlockDriverState (or NULL).
4659 * Return 0 on success, otherwise return < 0 and set @errp.
4661 * The caller must hold the AioContext lock of @reopen_state->bs.
4662 * @reopen_state->bs can move to a different AioContext in this function.
4663 * Callers must make sure that their AioContext locking is still correct after
4666 static int bdrv_reopen_parse_file_or_backing(BDRVReopenState
*reopen_state
,
4667 bool is_backing
, Transaction
*tran
,
4670 BlockDriverState
*bs
= reopen_state
->bs
;
4671 BlockDriverState
*new_child_bs
;
4672 BlockDriverState
*old_child_bs
= is_backing
? child_bs(bs
->backing
) :
4674 const char *child_name
= is_backing
? "backing" : "file";
4677 AioContext
*ctx
, *old_ctx
;
4680 GLOBAL_STATE_CODE();
4682 value
= qdict_get(reopen_state
->options
, child_name
);
4683 if (value
== NULL
) {
4687 switch (qobject_type(value
)) {
4689 assert(is_backing
); /* The 'file' option does not allow a null value */
4690 new_child_bs
= NULL
;
4693 str
= qstring_get_str(qobject_to(QString
, value
));
4694 new_child_bs
= bdrv_lookup_bs(NULL
, str
, errp
);
4695 if (new_child_bs
== NULL
) {
4697 } else if (bdrv_recurse_has_child(new_child_bs
, bs
)) {
4698 error_setg(errp
, "Making '%s' a %s child of '%s' would create a "
4699 "cycle", str
, child_name
, bs
->node_name
);
4705 * The options QDict has been flattened, so 'backing' and 'file'
4706 * do not allow any other data type here.
4708 g_assert_not_reached();
4711 if (old_child_bs
== new_child_bs
) {
4716 if (bdrv_skip_implicit_filters(old_child_bs
) == new_child_bs
) {
4720 if (old_child_bs
->implicit
) {
4721 error_setg(errp
, "Cannot replace implicit %s child of %s",
4722 child_name
, bs
->node_name
);
4727 if (bs
->drv
->is_filter
&& !old_child_bs
) {
4729 * Filters always have a file or a backing child, so we are trying to
4730 * change wrong child
4732 error_setg(errp
, "'%s' is a %s filter node that does not support a "
4733 "%s child", bs
->node_name
, bs
->drv
->format_name
, child_name
);
4738 reopen_state
->old_backing_bs
= old_child_bs
;
4740 reopen_state
->old_file_bs
= old_child_bs
;
4743 old_ctx
= bdrv_get_aio_context(bs
);
4744 ctx
= bdrv_get_aio_context(new_child_bs
);
4745 if (old_ctx
!= ctx
) {
4746 aio_context_release(old_ctx
);
4747 aio_context_acquire(ctx
);
4750 ret
= bdrv_set_file_or_backing_noperm(bs
, new_child_bs
, is_backing
,
4753 if (old_ctx
!= ctx
) {
4754 aio_context_release(ctx
);
4755 aio_context_acquire(old_ctx
);
4762 * Prepares a BlockDriverState for reopen. All changes are staged in the
4763 * 'opaque' field of the BDRVReopenState, which is used and allocated by
4764 * the block driver layer .bdrv_reopen_prepare()
4766 * bs is the BlockDriverState to reopen
4767 * flags are the new open flags
4768 * queue is the reopen queue
4770 * Returns 0 on success, non-zero on error. On error errp will be set
4773 * On failure, bdrv_reopen_abort() will be called to clean up any data.
4774 * It is the responsibility of the caller to then call the abort() or
4775 * commit() for any other BDS that have been left in a prepare() state
4777 * The caller must hold the AioContext lock of @reopen_state->bs.
4779 static int bdrv_reopen_prepare(BDRVReopenState
*reopen_state
,
4780 BlockReopenQueue
*queue
,
4781 Transaction
*change_child_tran
, Error
**errp
)
4785 Error
*local_err
= NULL
;
4788 QDict
*orig_reopen_opts
;
4789 char *discard
= NULL
;
4791 bool drv_prepared
= false;
4793 assert(reopen_state
!= NULL
);
4794 assert(reopen_state
->bs
->drv
!= NULL
);
4795 GLOBAL_STATE_CODE();
4796 drv
= reopen_state
->bs
->drv
;
4798 /* This function and each driver's bdrv_reopen_prepare() remove
4799 * entries from reopen_state->options as they are processed, so
4800 * we need to make a copy of the original QDict. */
4801 orig_reopen_opts
= qdict_clone_shallow(reopen_state
->options
);
4803 /* Process generic block layer options */
4804 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
4805 if (!qemu_opts_absorb_qdict(opts
, reopen_state
->options
, errp
)) {
4810 /* This was already called in bdrv_reopen_queue_child() so the flags
4811 * are up-to-date. This time we simply want to remove the options from
4812 * QemuOpts in order to indicate that they have been processed. */
4813 old_flags
= reopen_state
->flags
;
4814 update_flags_from_options(&reopen_state
->flags
, opts
);
4815 assert(old_flags
== reopen_state
->flags
);
4817 discard
= qemu_opt_get_del(opts
, BDRV_OPT_DISCARD
);
4818 if (discard
!= NULL
) {
4819 if (bdrv_parse_discard_flags(discard
, &reopen_state
->flags
) != 0) {
4820 error_setg(errp
, "Invalid discard option");
4826 reopen_state
->detect_zeroes
=
4827 bdrv_parse_detect_zeroes(opts
, reopen_state
->flags
, &local_err
);
4829 error_propagate(errp
, local_err
);
4834 /* All other options (including node-name and driver) must be unchanged.
4835 * Put them back into the QDict, so that they are checked at the end
4836 * of this function. */
4837 qemu_opts_to_qdict(opts
, reopen_state
->options
);
4839 /* If we are to stay read-only, do not allow permission change
4840 * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is
4841 * not set, or if the BDS still has copy_on_read enabled */
4842 read_only
= !(reopen_state
->flags
& BDRV_O_RDWR
);
4843 ret
= bdrv_can_set_read_only(reopen_state
->bs
, read_only
, true, &local_err
);
4845 error_propagate(errp
, local_err
);
4849 if (drv
->bdrv_reopen_prepare
) {
4851 * If a driver-specific option is missing, it means that we
4852 * should reset it to its default value.
4853 * But not all options allow that, so we need to check it first.
4855 ret
= bdrv_reset_options_allowed(reopen_state
->bs
,
4856 reopen_state
->options
, errp
);
4861 ret
= drv
->bdrv_reopen_prepare(reopen_state
, queue
, &local_err
);
4863 if (local_err
!= NULL
) {
4864 error_propagate(errp
, local_err
);
4866 bdrv_refresh_filename(reopen_state
->bs
);
4867 error_setg(errp
, "failed while preparing to reopen image '%s'",
4868 reopen_state
->bs
->filename
);
4873 /* It is currently mandatory to have a bdrv_reopen_prepare()
4874 * handler for each supported drv. */
4875 error_setg(errp
, "Block format '%s' used by node '%s' "
4876 "does not support reopening files", drv
->format_name
,
4877 bdrv_get_device_or_node_name(reopen_state
->bs
));
4882 drv_prepared
= true;
4885 * We must provide the 'backing' option if the BDS has a backing
4886 * file or if the image file has a backing file name as part of
4887 * its metadata. Otherwise the 'backing' option can be omitted.
4889 if (drv
->supports_backing
&& reopen_state
->backing_missing
&&
4890 (reopen_state
->bs
->backing
|| reopen_state
->bs
->backing_file
[0])) {
4891 error_setg(errp
, "backing is missing for '%s'",
4892 reopen_state
->bs
->node_name
);
4898 * Allow changing the 'backing' option. The new value can be
4899 * either a reference to an existing node (using its node name)
4900 * or NULL to simply detach the current backing file.
4902 ret
= bdrv_reopen_parse_file_or_backing(reopen_state
, true,
4903 change_child_tran
, errp
);
4907 qdict_del(reopen_state
->options
, "backing");
4909 /* Allow changing the 'file' option. In this case NULL is not allowed */
4910 ret
= bdrv_reopen_parse_file_or_backing(reopen_state
, false,
4911 change_child_tran
, errp
);
4915 qdict_del(reopen_state
->options
, "file");
4917 /* Options that are not handled are only okay if they are unchanged
4918 * compared to the old state. It is expected that some options are only
4919 * used for the initial open, but not reopen (e.g. filename) */
4920 if (qdict_size(reopen_state
->options
)) {
4921 const QDictEntry
*entry
= qdict_first(reopen_state
->options
);
4924 QObject
*new = entry
->value
;
4925 QObject
*old
= qdict_get(reopen_state
->bs
->options
, entry
->key
);
4927 /* Allow child references (child_name=node_name) as long as they
4928 * point to the current child (i.e. everything stays the same). */
4929 if (qobject_type(new) == QTYPE_QSTRING
) {
4931 QLIST_FOREACH(child
, &reopen_state
->bs
->children
, next
) {
4932 if (!strcmp(child
->name
, entry
->key
)) {
4938 if (!strcmp(child
->bs
->node_name
,
4939 qstring_get_str(qobject_to(QString
, new)))) {
4940 continue; /* Found child with this name, skip option */
4946 * TODO: When using -drive to specify blockdev options, all values
4947 * will be strings; however, when using -blockdev, blockdev-add or
4948 * filenames using the json:{} pseudo-protocol, they will be
4950 * In contrast, reopening options are (currently) always strings
4951 * (because you can only specify them through qemu-io; all other
4952 * callers do not specify any options).
4953 * Therefore, when using anything other than -drive to create a BDS,
4954 * this cannot detect non-string options as unchanged, because
4955 * qobject_is_equal() always returns false for objects of different
4956 * type. In the future, this should be remedied by correctly typing
4957 * all options. For now, this is not too big of an issue because
4958 * the user can simply omit options which cannot be changed anyway,
4959 * so they will stay unchanged.
4961 if (!qobject_is_equal(new, old
)) {
4962 error_setg(errp
, "Cannot change the option '%s'", entry
->key
);
4966 } while ((entry
= qdict_next(reopen_state
->options
, entry
)));
4971 /* Restore the original reopen_state->options QDict */
4972 qobject_unref(reopen_state
->options
);
4973 reopen_state
->options
= qobject_ref(orig_reopen_opts
);
4976 if (ret
< 0 && drv_prepared
) {
4977 /* drv->bdrv_reopen_prepare() has succeeded, so we need to
4978 * call drv->bdrv_reopen_abort() before signaling an error
4979 * (bdrv_reopen_multiple() will not call bdrv_reopen_abort()
4980 * when the respective bdrv_reopen_prepare() has failed) */
4981 if (drv
->bdrv_reopen_abort
) {
4982 drv
->bdrv_reopen_abort(reopen_state
);
4985 qemu_opts_del(opts
);
4986 qobject_unref(orig_reopen_opts
);
4992 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
4993 * makes them final by swapping the staging BlockDriverState contents into
4994 * the active BlockDriverState contents.
4996 static void bdrv_reopen_commit(BDRVReopenState
*reopen_state
)
4999 BlockDriverState
*bs
;
5002 assert(reopen_state
!= NULL
);
5003 bs
= reopen_state
->bs
;
5005 assert(drv
!= NULL
);
5006 GLOBAL_STATE_CODE();
5008 /* If there are any driver level actions to take */
5009 if (drv
->bdrv_reopen_commit
) {
5010 drv
->bdrv_reopen_commit(reopen_state
);
5013 /* set BDS specific flags now */
5014 qobject_unref(bs
->explicit_options
);
5015 qobject_unref(bs
->options
);
5016 qobject_ref(reopen_state
->explicit_options
);
5017 qobject_ref(reopen_state
->options
);
5019 bs
->explicit_options
= reopen_state
->explicit_options
;
5020 bs
->options
= reopen_state
->options
;
5021 bs
->open_flags
= reopen_state
->flags
;
5022 bs
->detect_zeroes
= reopen_state
->detect_zeroes
;
5024 /* Remove child references from bs->options and bs->explicit_options.
5025 * Child options were already removed in bdrv_reopen_queue_child() */
5026 QLIST_FOREACH(child
, &bs
->children
, next
) {
5027 qdict_del(bs
->explicit_options
, child
->name
);
5028 qdict_del(bs
->options
, child
->name
);
5030 /* backing is probably removed, so it's not handled by previous loop */
5031 qdict_del(bs
->explicit_options
, "backing");
5032 qdict_del(bs
->options
, "backing");
5034 bdrv_graph_rdlock_main_loop();
5035 bdrv_refresh_limits(bs
, NULL
, NULL
);
5036 bdrv_graph_rdunlock_main_loop();
5037 bdrv_refresh_total_sectors(bs
, bs
->total_sectors
);
5041 * Abort the reopen, and delete and free the staged changes in
5044 static void bdrv_reopen_abort(BDRVReopenState
*reopen_state
)
5048 assert(reopen_state
!= NULL
);
5049 drv
= reopen_state
->bs
->drv
;
5050 assert(drv
!= NULL
);
5051 GLOBAL_STATE_CODE();
5053 if (drv
->bdrv_reopen_abort
) {
5054 drv
->bdrv_reopen_abort(reopen_state
);
5059 static void bdrv_close(BlockDriverState
*bs
)
5061 BdrvAioNotifier
*ban
, *ban_next
;
5062 BdrvChild
*child
, *next
;
5064 GLOBAL_STATE_CODE();
5065 assert(!bs
->refcnt
);
5067 bdrv_drained_begin(bs
); /* complete I/O */
5069 bdrv_drain(bs
); /* in case flush left pending I/O */
5072 if (bs
->drv
->bdrv_close
) {
5073 /* Must unfreeze all children, so bdrv_unref_child() works */
5074 bs
->drv
->bdrv_close(bs
);
5079 QLIST_FOREACH_SAFE(child
, &bs
->children
, next
, next
) {
5080 bdrv_unref_child(bs
, child
);
5083 assert(!bs
->backing
);
5087 qatomic_set(&bs
->copy_on_read
, 0);
5088 bs
->backing_file
[0] = '\0';
5089 bs
->backing_format
[0] = '\0';
5090 bs
->total_sectors
= 0;
5091 bs
->encrypted
= false;
5093 qobject_unref(bs
->options
);
5094 qobject_unref(bs
->explicit_options
);
5096 bs
->explicit_options
= NULL
;
5097 qobject_unref(bs
->full_open_options
);
5098 bs
->full_open_options
= NULL
;
5099 g_free(bs
->block_status_cache
);
5100 bs
->block_status_cache
= NULL
;
5102 bdrv_release_named_dirty_bitmaps(bs
);
5103 assert(QLIST_EMPTY(&bs
->dirty_bitmaps
));
5105 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_next
) {
5108 QLIST_INIT(&bs
->aio_notifiers
);
5109 bdrv_drained_end(bs
);
5112 * If we're still inside some bdrv_drain_all_begin()/end() sections, end
5113 * them now since this BDS won't exist anymore when bdrv_drain_all_end()
5116 if (bs
->quiesce_counter
) {
5117 bdrv_drain_all_end_quiesce(bs
);
5121 void bdrv_close_all(void)
5123 GLOBAL_STATE_CODE();
5124 assert(job_next(NULL
) == NULL
);
5126 /* Drop references from requests still in flight, such as canceled block
5127 * jobs whose AIO context has not been polled yet */
5130 blk_remove_all_bs();
5131 blockdev_close_all_bdrv_states();
5133 assert(QTAILQ_EMPTY(&all_bdrv_states
));
5136 static bool should_update_child(BdrvChild
*c
, BlockDriverState
*to
)
5142 if (c
->klass
->stay_at_node
) {
5146 /* If the child @c belongs to the BDS @to, replacing the current
5147 * c->bs by @to would mean to create a loop.
5149 * Such a case occurs when appending a BDS to a backing chain.
5150 * For instance, imagine the following chain:
5152 * guest device -> node A -> further backing chain...
5154 * Now we create a new BDS B which we want to put on top of this
5155 * chain, so we first attach A as its backing node:
5160 * guest device -> node A -> further backing chain...
5162 * Finally we want to replace A by B. When doing that, we want to
5163 * replace all pointers to A by pointers to B -- except for the
5164 * pointer from B because (1) that would create a loop, and (2)
5165 * that pointer should simply stay intact:
5167 * guest device -> node B
5170 * node A -> further backing chain...
5172 * In general, when replacing a node A (c->bs) by a node B (@to),
5173 * if A is a child of B, that means we cannot replace A by B there
5174 * because that would create a loop. Silently detaching A from B
5175 * is also not really an option. So overall just leaving A in
5176 * place there is the most sensible choice.
5178 * We would also create a loop in any cases where @c is only
5179 * indirectly referenced by @to. Prevent this by returning false
5180 * if @c is found (by breadth-first search) anywhere in the whole
5185 found
= g_hash_table_new(NULL
, NULL
);
5186 g_hash_table_add(found
, to
);
5187 queue
= g_queue_new();
5188 g_queue_push_tail(queue
, to
);
5190 while (!g_queue_is_empty(queue
)) {
5191 BlockDriverState
*v
= g_queue_pop_head(queue
);
5194 QLIST_FOREACH(c2
, &v
->children
, next
) {
5200 if (g_hash_table_contains(found
, c2
->bs
)) {
5204 g_queue_push_tail(queue
, c2
->bs
);
5205 g_hash_table_add(found
, c2
->bs
);
5209 g_queue_free(queue
);
5210 g_hash_table_destroy(found
);
5215 static void bdrv_remove_child_commit(void *opaque
)
5217 GLOBAL_STATE_CODE();
5218 bdrv_child_free(opaque
);
5221 static TransactionActionDrv bdrv_remove_child_drv
= {
5222 .commit
= bdrv_remove_child_commit
,
5225 /* Function doesn't update permissions, caller is responsible for this. */
5226 static void bdrv_remove_child(BdrvChild
*child
, Transaction
*tran
)
5233 BlockDriverState
*bs
= child
->bs
;
5234 bdrv_drained_begin(bs
);
5235 bdrv_replace_child_tran(child
, NULL
, tran
);
5236 bdrv_drained_end(bs
);
5239 tran_add(tran
, &bdrv_remove_child_drv
, child
);
5242 static void undrain_on_clean_cb(void *opaque
)
5244 bdrv_drained_end(opaque
);
5247 static TransactionActionDrv undrain_on_clean
= {
5248 .clean
= undrain_on_clean_cb
,
5251 static int bdrv_replace_node_noperm(BlockDriverState
*from
,
5252 BlockDriverState
*to
,
5253 bool auto_skip
, Transaction
*tran
,
5256 BdrvChild
*c
, *next
;
5258 GLOBAL_STATE_CODE();
5260 bdrv_drained_begin(from
);
5261 bdrv_drained_begin(to
);
5262 tran_add(tran
, &undrain_on_clean
, from
);
5263 tran_add(tran
, &undrain_on_clean
, to
);
5265 QLIST_FOREACH_SAFE(c
, &from
->parents
, next_parent
, next
) {
5266 assert(c
->bs
== from
);
5267 if (!should_update_child(c
, to
)) {
5271 error_setg(errp
, "Should not change '%s' link to '%s'",
5272 c
->name
, from
->node_name
);
5276 error_setg(errp
, "Cannot change '%s' link to '%s'",
5277 c
->name
, from
->node_name
);
5280 bdrv_replace_child_tran(c
, to
, tran
);
5287 * With auto_skip=true bdrv_replace_node_common skips updating from parents
5288 * if it creates a parent-child relation loop or if parent is block-job.
5290 * With auto_skip=false the error is returned if from has a parent which should
5293 * With @detach_subchain=true @to must be in a backing chain of @from. In this
5294 * case backing link of the cow-parent of @to is removed.
5296 static int bdrv_replace_node_common(BlockDriverState
*from
,
5297 BlockDriverState
*to
,
5298 bool auto_skip
, bool detach_subchain
,
5301 Transaction
*tran
= tran_new();
5302 g_autoptr(GSList
) refresh_list
= NULL
;
5303 BlockDriverState
*to_cow_parent
= NULL
;
5306 GLOBAL_STATE_CODE();
5308 if (detach_subchain
) {
5309 assert(bdrv_chain_contains(from
, to
));
5311 for (to_cow_parent
= from
;
5312 bdrv_filter_or_cow_bs(to_cow_parent
) != to
;
5313 to_cow_parent
= bdrv_filter_or_cow_bs(to_cow_parent
))
5319 /* Make sure that @from doesn't go away until we have successfully attached
5320 * all of its parents to @to. */
5323 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
5324 assert(bdrv_get_aio_context(from
) == bdrv_get_aio_context(to
));
5325 bdrv_drained_begin(from
);
5328 * Do the replacement without permission update.
5329 * Replacement may influence the permissions, we should calculate new
5330 * permissions based on new graph. If we fail, we'll roll-back the
5333 ret
= bdrv_replace_node_noperm(from
, to
, auto_skip
, tran
, errp
);
5338 if (detach_subchain
) {
5339 bdrv_remove_child(bdrv_filter_or_cow_child(to_cow_parent
), tran
);
5342 refresh_list
= g_slist_prepend(refresh_list
, to
);
5343 refresh_list
= g_slist_prepend(refresh_list
, from
);
5345 ret
= bdrv_list_refresh_perms(refresh_list
, NULL
, tran
, errp
);
5353 tran_finalize(tran
, ret
);
5355 bdrv_drained_end(from
);
5361 int bdrv_replace_node(BlockDriverState
*from
, BlockDriverState
*to
,
5364 GLOBAL_STATE_CODE();
5366 return bdrv_replace_node_common(from
, to
, true, false, errp
);
5369 int bdrv_drop_filter(BlockDriverState
*bs
, Error
**errp
)
5371 GLOBAL_STATE_CODE();
5373 return bdrv_replace_node_common(bs
, bdrv_filter_or_cow_bs(bs
), true, true,
5378 * Add new bs contents at the top of an image chain while the chain is
5379 * live, while keeping required fields on the top layer.
5381 * This will modify the BlockDriverState fields, and swap contents
5382 * between bs_new and bs_top. Both bs_new and bs_top are modified.
5384 * bs_new must not be attached to a BlockBackend and must not have backing
5387 * This function does not create any image files.
5389 * The caller must hold the AioContext lock for @bs_top.
5391 int bdrv_append(BlockDriverState
*bs_new
, BlockDriverState
*bs_top
,
5396 Transaction
*tran
= tran_new();
5397 AioContext
*old_context
, *new_context
= NULL
;
5399 GLOBAL_STATE_CODE();
5401 assert(!bs_new
->backing
);
5403 old_context
= bdrv_get_aio_context(bs_top
);
5405 child
= bdrv_attach_child_noperm(bs_new
, bs_top
, "backing",
5406 &child_of_bds
, bdrv_backing_role(bs_new
),
5414 * bdrv_attach_child_noperm could change the AioContext of bs_top.
5415 * bdrv_replace_node_noperm calls bdrv_drained_begin, so let's temporarily
5416 * hold the new AioContext, since bdrv_drained_begin calls BDRV_POLL_WHILE
5417 * that assumes the new lock is taken.
5419 new_context
= bdrv_get_aio_context(bs_top
);
5421 if (old_context
!= new_context
) {
5422 aio_context_release(old_context
);
5423 aio_context_acquire(new_context
);
5426 ret
= bdrv_replace_node_noperm(bs_top
, bs_new
, true, tran
, errp
);
5431 ret
= bdrv_refresh_perms(bs_new
, tran
, errp
);
5433 tran_finalize(tran
, ret
);
5435 bdrv_graph_rdlock_main_loop();
5436 bdrv_refresh_limits(bs_top
, NULL
, NULL
);
5437 bdrv_graph_rdunlock_main_loop();
5439 if (new_context
&& old_context
!= new_context
) {
5440 aio_context_release(new_context
);
5441 aio_context_acquire(old_context
);
5447 /* Not for empty child */
5448 int bdrv_replace_child_bs(BdrvChild
*child
, BlockDriverState
*new_bs
,
5452 Transaction
*tran
= tran_new();
5453 g_autoptr(GSList
) refresh_list
= NULL
;
5454 BlockDriverState
*old_bs
= child
->bs
;
5456 GLOBAL_STATE_CODE();
5459 bdrv_drained_begin(old_bs
);
5460 bdrv_drained_begin(new_bs
);
5462 bdrv_replace_child_tran(child
, new_bs
, tran
);
5464 refresh_list
= g_slist_prepend(refresh_list
, old_bs
);
5465 refresh_list
= g_slist_prepend(refresh_list
, new_bs
);
5467 ret
= bdrv_list_refresh_perms(refresh_list
, NULL
, tran
, errp
);
5469 tran_finalize(tran
, ret
);
5471 bdrv_drained_end(old_bs
);
5472 bdrv_drained_end(new_bs
);
5478 static void bdrv_delete(BlockDriverState
*bs
)
5480 assert(bdrv_op_blocker_is_empty(bs
));
5481 assert(!bs
->refcnt
);
5482 GLOBAL_STATE_CODE();
5484 /* remove from list, if necessary */
5485 if (bs
->node_name
[0] != '\0') {
5486 QTAILQ_REMOVE(&graph_bdrv_states
, bs
, node_list
);
5488 QTAILQ_REMOVE(&all_bdrv_states
, bs
, bs_list
);
5492 qemu_mutex_destroy(&bs
->reqs_lock
);
5499 * Replace @bs by newly created block node.
5501 * @options is a QDict of options to pass to the block drivers, or NULL for an
5502 * empty set of options. The reference to the QDict belongs to the block layer
5503 * after the call (even on failure), so if the caller intends to reuse the
5504 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
5506 * The caller holds the AioContext lock for @bs. It must make sure that @bs
5507 * stays in the same AioContext, i.e. @options must not refer to nodes in a
5508 * different AioContext.
5510 BlockDriverState
*bdrv_insert_node(BlockDriverState
*bs
, QDict
*options
,
5511 int flags
, Error
**errp
)
5515 AioContext
*ctx
= bdrv_get_aio_context(bs
);
5516 BlockDriverState
*new_node_bs
= NULL
;
5517 const char *drvname
, *node_name
;
5520 drvname
= qdict_get_try_str(options
, "driver");
5522 error_setg(errp
, "driver is not specified");
5526 drv
= bdrv_find_format(drvname
);
5528 error_setg(errp
, "Unknown driver: '%s'", drvname
);
5532 node_name
= qdict_get_try_str(options
, "node-name");
5534 GLOBAL_STATE_CODE();
5536 aio_context_release(ctx
);
5537 aio_context_acquire(qemu_get_aio_context());
5538 new_node_bs
= bdrv_new_open_driver_opts(drv
, node_name
, options
, flags
,
5540 aio_context_release(qemu_get_aio_context());
5541 aio_context_acquire(ctx
);
5542 assert(bdrv_get_aio_context(bs
) == ctx
);
5544 options
= NULL
; /* bdrv_new_open_driver() eats options */
5546 error_prepend(errp
, "Could not create node: ");
5550 bdrv_drained_begin(bs
);
5551 ret
= bdrv_replace_node(bs
, new_node_bs
, errp
);
5552 bdrv_drained_end(bs
);
5555 error_prepend(errp
, "Could not replace node: ");
5562 qobject_unref(options
);
5563 bdrv_unref(new_node_bs
);
5568 * Run consistency checks on an image
5570 * Returns 0 if the check could be completed (it doesn't mean that the image is
5571 * free of errors) or -errno when an internal error occurred. The results of the
5572 * check are stored in res.
5574 int coroutine_fn
bdrv_co_check(BlockDriverState
*bs
,
5575 BdrvCheckResult
*res
, BdrvCheckMode fix
)
5578 assert_bdrv_graph_readable();
5579 if (bs
->drv
== NULL
) {
5582 if (bs
->drv
->bdrv_co_check
== NULL
) {
5586 memset(res
, 0, sizeof(*res
));
5587 return bs
->drv
->bdrv_co_check(bs
, res
, fix
);
5593 * -EINVAL - backing format specified, but no file
5594 * -ENOSPC - can't update the backing file because no space is left in the
5596 * -ENOTSUP - format driver doesn't support changing the backing file
5598 int bdrv_change_backing_file(BlockDriverState
*bs
, const char *backing_file
,
5599 const char *backing_fmt
, bool require
)
5601 BlockDriver
*drv
= bs
->drv
;
5604 GLOBAL_STATE_CODE();
5610 /* Backing file format doesn't make sense without a backing file */
5611 if (backing_fmt
&& !backing_file
) {
5615 if (require
&& backing_file
&& !backing_fmt
) {
5619 if (drv
->bdrv_change_backing_file
!= NULL
) {
5620 ret
= drv
->bdrv_change_backing_file(bs
, backing_file
, backing_fmt
);
5626 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
), backing_file
?: "");
5627 pstrcpy(bs
->backing_format
, sizeof(bs
->backing_format
), backing_fmt
?: "");
5628 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
5629 backing_file
?: "");
5635 * Finds the first non-filter node above bs in the chain between
5636 * active and bs. The returned node is either an immediate parent of
5637 * bs, or there are only filter nodes between the two.
5639 * Returns NULL if bs is not found in active's image chain,
5640 * or if active == bs.
5642 * Returns the bottommost base image if bs == NULL.
5644 BlockDriverState
*bdrv_find_overlay(BlockDriverState
*active
,
5645 BlockDriverState
*bs
)
5648 GLOBAL_STATE_CODE();
5650 bs
= bdrv_skip_filters(bs
);
5651 active
= bdrv_skip_filters(active
);
5654 BlockDriverState
*next
= bdrv_backing_chain_next(active
);
5664 /* Given a BDS, searches for the base layer. */
5665 BlockDriverState
*bdrv_find_base(BlockDriverState
*bs
)
5667 GLOBAL_STATE_CODE();
5669 return bdrv_find_overlay(bs
, NULL
);
5673 * Return true if at least one of the COW (backing) and filter links
5674 * between @bs and @base is frozen. @errp is set if that's the case.
5675 * @base must be reachable from @bs, or NULL.
5677 bool bdrv_is_backing_chain_frozen(BlockDriverState
*bs
, BlockDriverState
*base
,
5680 BlockDriverState
*i
;
5683 GLOBAL_STATE_CODE();
5685 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5686 child
= bdrv_filter_or_cow_child(i
);
5688 if (child
&& child
->frozen
) {
5689 error_setg(errp
, "Cannot change '%s' link from '%s' to '%s'",
5690 child
->name
, i
->node_name
, child
->bs
->node_name
);
5699 * Freeze all COW (backing) and filter links between @bs and @base.
5700 * If any of the links is already frozen the operation is aborted and
5701 * none of the links are modified.
5702 * @base must be reachable from @bs, or NULL.
5703 * Returns 0 on success. On failure returns < 0 and sets @errp.
5705 int bdrv_freeze_backing_chain(BlockDriverState
*bs
, BlockDriverState
*base
,
5708 BlockDriverState
*i
;
5711 GLOBAL_STATE_CODE();
5713 if (bdrv_is_backing_chain_frozen(bs
, base
, errp
)) {
5717 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5718 child
= bdrv_filter_or_cow_child(i
);
5719 if (child
&& child
->bs
->never_freeze
) {
5720 error_setg(errp
, "Cannot freeze '%s' link to '%s'",
5721 child
->name
, child
->bs
->node_name
);
5726 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5727 child
= bdrv_filter_or_cow_child(i
);
5729 child
->frozen
= true;
5737 * Unfreeze all COW (backing) and filter links between @bs and @base.
5738 * The caller must ensure that all links are frozen before using this
5740 * @base must be reachable from @bs, or NULL.
5742 void bdrv_unfreeze_backing_chain(BlockDriverState
*bs
, BlockDriverState
*base
)
5744 BlockDriverState
*i
;
5747 GLOBAL_STATE_CODE();
5749 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5750 child
= bdrv_filter_or_cow_child(i
);
5752 assert(child
->frozen
);
5753 child
->frozen
= false;
5759 * Drops images above 'base' up to and including 'top', and sets the image
5760 * above 'top' to have base as its backing file.
5762 * Requires that the overlay to 'top' is opened r/w, so that the backing file
5763 * information in 'bs' can be properly updated.
5765 * E.g., this will convert the following chain:
5766 * bottom <- base <- intermediate <- top <- active
5770 * bottom <- base <- active
5772 * It is allowed for bottom==base, in which case it converts:
5774 * base <- intermediate <- top <- active
5780 * If backing_file_str is non-NULL, it will be used when modifying top's
5781 * overlay image metadata.
5784 * if active == top, that is considered an error
5787 int bdrv_drop_intermediate(BlockDriverState
*top
, BlockDriverState
*base
,
5788 const char *backing_file_str
)
5790 BlockDriverState
*explicit_top
= top
;
5791 bool update_inherits_from
;
5793 Error
*local_err
= NULL
;
5795 g_autoptr(GSList
) updated_children
= NULL
;
5798 GLOBAL_STATE_CODE();
5801 bdrv_drained_begin(base
);
5803 if (!top
->drv
|| !base
->drv
) {
5807 /* Make sure that base is in the backing chain of top */
5808 if (!bdrv_chain_contains(top
, base
)) {
5812 /* If 'base' recursively inherits from 'top' then we should set
5813 * base->inherits_from to top->inherits_from after 'top' and all
5814 * other intermediate nodes have been dropped.
5815 * If 'top' is an implicit node (e.g. "commit_top") we should skip
5816 * it because no one inherits from it. We use explicit_top for that. */
5817 explicit_top
= bdrv_skip_implicit_filters(explicit_top
);
5818 update_inherits_from
= bdrv_inherits_from_recursive(base
, explicit_top
);
5820 /* success - we can delete the intermediate states, and link top->base */
5821 if (!backing_file_str
) {
5822 bdrv_refresh_filename(base
);
5823 backing_file_str
= base
->filename
;
5826 QLIST_FOREACH(c
, &top
->parents
, next_parent
) {
5827 updated_children
= g_slist_prepend(updated_children
, c
);
5831 * It seems correct to pass detach_subchain=true here, but it triggers
5832 * one more yet not fixed bug, when due to nested aio_poll loop we switch to
5833 * another drained section, which modify the graph (for example, removing
5834 * the child, which we keep in updated_children list). So, it's a TODO.
5836 * Note, bug triggered if pass detach_subchain=true here and run
5837 * test-bdrv-drain. test_drop_intermediate_poll() test-case will crash.
5840 bdrv_replace_node_common(top
, base
, false, false, &local_err
);
5842 error_report_err(local_err
);
5846 for (p
= updated_children
; p
; p
= p
->next
) {
5849 if (c
->klass
->update_filename
) {
5850 ret
= c
->klass
->update_filename(c
, base
, backing_file_str
,
5854 * TODO: Actually, we want to rollback all previous iterations
5855 * of this loop, and (which is almost impossible) previous
5856 * bdrv_replace_node()...
5858 * Note, that c->klass->update_filename may lead to permission
5859 * update, so it's a bad idea to call it inside permission
5860 * update transaction of bdrv_replace_node.
5862 error_report_err(local_err
);
5868 if (update_inherits_from
) {
5869 base
->inherits_from
= explicit_top
->inherits_from
;
5874 bdrv_drained_end(base
);
5880 * Implementation of BlockDriver.bdrv_co_get_allocated_file_size() that
5881 * sums the size of all data-bearing children. (This excludes backing
5884 static int64_t coroutine_fn GRAPH_RDLOCK
5885 bdrv_sum_allocated_file_size(BlockDriverState
*bs
)
5888 int64_t child_size
, sum
= 0;
5890 QLIST_FOREACH(child
, &bs
->children
, next
) {
5891 if (child
->role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
|
5892 BDRV_CHILD_FILTERED
))
5894 child_size
= bdrv_co_get_allocated_file_size(child
->bs
);
5895 if (child_size
< 0) {
5906 * Length of a allocated file in bytes. Sparse files are counted by actual
5907 * allocated space. Return < 0 if error or unknown.
5909 int64_t coroutine_fn
bdrv_co_get_allocated_file_size(BlockDriverState
*bs
)
5911 BlockDriver
*drv
= bs
->drv
;
5913 assert_bdrv_graph_readable();
5918 if (drv
->bdrv_co_get_allocated_file_size
) {
5919 return drv
->bdrv_co_get_allocated_file_size(bs
);
5922 if (drv
->bdrv_file_open
) {
5924 * Protocol drivers default to -ENOTSUP (most of their data is
5925 * not stored in any of their children (if they even have any),
5926 * so there is no generic way to figure it out).
5929 } else if (drv
->is_filter
) {
5930 /* Filter drivers default to the size of their filtered child */
5931 return bdrv_co_get_allocated_file_size(bdrv_filter_bs(bs
));
5933 /* Other drivers default to summing their children's sizes */
5934 return bdrv_sum_allocated_file_size(bs
);
5940 * @drv: Format driver
5941 * @opts: Creation options for new image
5942 * @in_bs: Existing image containing data for new image (may be NULL)
5943 * @errp: Error object
5944 * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo())
5947 * Calculate file size required to create a new image.
5949 * If @in_bs is given then space for allocated clusters and zero clusters
5950 * from that image are included in the calculation. If @opts contains a
5951 * backing file that is shared by @in_bs then backing clusters may be omitted
5952 * from the calculation.
5954 * If @in_bs is NULL then the calculation includes no allocated clusters
5955 * unless a preallocation option is given in @opts.
5957 * Note that @in_bs may use a different BlockDriver from @drv.
5959 * If an error occurs the @errp pointer is set.
5961 BlockMeasureInfo
*bdrv_measure(BlockDriver
*drv
, QemuOpts
*opts
,
5962 BlockDriverState
*in_bs
, Error
**errp
)
5965 if (!drv
->bdrv_measure
) {
5966 error_setg(errp
, "Block driver '%s' does not support size measurement",
5971 return drv
->bdrv_measure(opts
, in_bs
, errp
);
5975 * Return number of sectors on success, -errno on error.
5977 int64_t coroutine_fn
bdrv_co_nb_sectors(BlockDriverState
*bs
)
5979 BlockDriver
*drv
= bs
->drv
;
5981 assert_bdrv_graph_readable();
5986 if (bs
->bl
.has_variable_length
) {
5987 int ret
= bdrv_co_refresh_total_sectors(bs
, bs
->total_sectors
);
5992 return bs
->total_sectors
;
5996 * This wrapper is written by hand because this function is in the hot I/O path,
5997 * via blk_get_geometry.
5999 int64_t coroutine_mixed_fn
bdrv_nb_sectors(BlockDriverState
*bs
)
6001 BlockDriver
*drv
= bs
->drv
;
6007 if (bs
->bl
.has_variable_length
) {
6008 int ret
= bdrv_refresh_total_sectors(bs
, bs
->total_sectors
);
6014 return bs
->total_sectors
;
6018 * Return length in bytes on success, -errno on error.
6019 * The length is always a multiple of BDRV_SECTOR_SIZE.
6021 int64_t coroutine_fn
bdrv_co_getlength(BlockDriverState
*bs
)
6025 assert_bdrv_graph_readable();
6027 ret
= bdrv_co_nb_sectors(bs
);
6031 if (ret
> INT64_MAX
/ BDRV_SECTOR_SIZE
) {
6034 return ret
* BDRV_SECTOR_SIZE
;
6037 bool bdrv_is_sg(BlockDriverState
*bs
)
6044 * Return whether the given node supports compressed writes.
6046 bool bdrv_supports_compressed_writes(BlockDriverState
*bs
)
6048 BlockDriverState
*filtered
;
6051 if (!bs
->drv
|| !block_driver_can_compress(bs
->drv
)) {
6055 filtered
= bdrv_filter_bs(bs
);
6058 * Filters can only forward compressed writes, so we have to
6061 return bdrv_supports_compressed_writes(filtered
);
6067 const char *bdrv_get_format_name(BlockDriverState
*bs
)
6070 return bs
->drv
? bs
->drv
->format_name
: NULL
;
6073 static int qsort_strcmp(const void *a
, const void *b
)
6075 return strcmp(*(char *const *)a
, *(char *const *)b
);
6078 void bdrv_iterate_format(void (*it
)(void *opaque
, const char *name
),
6079 void *opaque
, bool read_only
)
6084 const char **formats
= NULL
;
6086 GLOBAL_STATE_CODE();
6088 QLIST_FOREACH(drv
, &bdrv_drivers
, list
) {
6089 if (drv
->format_name
) {
6093 if (use_bdrv_whitelist
&& !bdrv_is_whitelisted(drv
, read_only
)) {
6097 while (formats
&& i
&& !found
) {
6098 found
= !strcmp(formats
[--i
], drv
->format_name
);
6102 formats
= g_renew(const char *, formats
, count
+ 1);
6103 formats
[count
++] = drv
->format_name
;
6108 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); i
++) {
6109 const char *format_name
= block_driver_modules
[i
].format_name
;
6115 if (use_bdrv_whitelist
&&
6116 !bdrv_format_is_whitelisted(format_name
, read_only
)) {
6120 while (formats
&& j
&& !found
) {
6121 found
= !strcmp(formats
[--j
], format_name
);
6125 formats
= g_renew(const char *, formats
, count
+ 1);
6126 formats
[count
++] = format_name
;
6131 qsort(formats
, count
, sizeof(formats
[0]), qsort_strcmp
);
6133 for (i
= 0; i
< count
; i
++) {
6134 it(opaque
, formats
[i
]);
6140 /* This function is to find a node in the bs graph */
6141 BlockDriverState
*bdrv_find_node(const char *node_name
)
6143 BlockDriverState
*bs
;
6146 GLOBAL_STATE_CODE();
6148 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
6149 if (!strcmp(node_name
, bs
->node_name
)) {
6156 /* Put this QMP function here so it can access the static graph_bdrv_states. */
6157 BlockDeviceInfoList
*bdrv_named_nodes_list(bool flat
,
6160 BlockDeviceInfoList
*list
;
6161 BlockDriverState
*bs
;
6163 GLOBAL_STATE_CODE();
6166 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
6167 BlockDeviceInfo
*info
= bdrv_block_device_info(NULL
, bs
, flat
, errp
);
6169 qapi_free_BlockDeviceInfoList(list
);
6172 QAPI_LIST_PREPEND(list
, info
);
6178 typedef struct XDbgBlockGraphConstructor
{
6179 XDbgBlockGraph
*graph
;
6180 GHashTable
*graph_nodes
;
6181 } XDbgBlockGraphConstructor
;
6183 static XDbgBlockGraphConstructor
*xdbg_graph_new(void)
6185 XDbgBlockGraphConstructor
*gr
= g_new(XDbgBlockGraphConstructor
, 1);
6187 gr
->graph
= g_new0(XDbgBlockGraph
, 1);
6188 gr
->graph_nodes
= g_hash_table_new(NULL
, NULL
);
6193 static XDbgBlockGraph
*xdbg_graph_finalize(XDbgBlockGraphConstructor
*gr
)
6195 XDbgBlockGraph
*graph
= gr
->graph
;
6197 g_hash_table_destroy(gr
->graph_nodes
);
6203 static uintptr_t xdbg_graph_node_num(XDbgBlockGraphConstructor
*gr
, void *node
)
6205 uintptr_t ret
= (uintptr_t)g_hash_table_lookup(gr
->graph_nodes
, node
);
6212 * Start counting from 1, not 0, because 0 interferes with not-found (NULL)
6213 * answer of g_hash_table_lookup.
6215 ret
= g_hash_table_size(gr
->graph_nodes
) + 1;
6216 g_hash_table_insert(gr
->graph_nodes
, node
, (void *)ret
);
6221 static void xdbg_graph_add_node(XDbgBlockGraphConstructor
*gr
, void *node
,
6222 XDbgBlockGraphNodeType type
, const char *name
)
6224 XDbgBlockGraphNode
*n
;
6226 n
= g_new0(XDbgBlockGraphNode
, 1);
6228 n
->id
= xdbg_graph_node_num(gr
, node
);
6230 n
->name
= g_strdup(name
);
6232 QAPI_LIST_PREPEND(gr
->graph
->nodes
, n
);
6235 static void xdbg_graph_add_edge(XDbgBlockGraphConstructor
*gr
, void *parent
,
6236 const BdrvChild
*child
)
6238 BlockPermission qapi_perm
;
6239 XDbgBlockGraphEdge
*edge
;
6240 GLOBAL_STATE_CODE();
6242 edge
= g_new0(XDbgBlockGraphEdge
, 1);
6244 edge
->parent
= xdbg_graph_node_num(gr
, parent
);
6245 edge
->child
= xdbg_graph_node_num(gr
, child
->bs
);
6246 edge
->name
= g_strdup(child
->name
);
6248 for (qapi_perm
= 0; qapi_perm
< BLOCK_PERMISSION__MAX
; qapi_perm
++) {
6249 uint64_t flag
= bdrv_qapi_perm_to_blk_perm(qapi_perm
);
6251 if (flag
& child
->perm
) {
6252 QAPI_LIST_PREPEND(edge
->perm
, qapi_perm
);
6254 if (flag
& child
->shared_perm
) {
6255 QAPI_LIST_PREPEND(edge
->shared_perm
, qapi_perm
);
6259 QAPI_LIST_PREPEND(gr
->graph
->edges
, edge
);
6263 XDbgBlockGraph
*bdrv_get_xdbg_block_graph(Error
**errp
)
6267 BlockDriverState
*bs
;
6269 XDbgBlockGraphConstructor
*gr
= xdbg_graph_new();
6271 GLOBAL_STATE_CODE();
6273 for (blk
= blk_all_next(NULL
); blk
; blk
= blk_all_next(blk
)) {
6274 char *allocated_name
= NULL
;
6275 const char *name
= blk_name(blk
);
6278 name
= allocated_name
= blk_get_attached_dev_id(blk
);
6280 xdbg_graph_add_node(gr
, blk
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND
,
6282 g_free(allocated_name
);
6283 if (blk_root(blk
)) {
6284 xdbg_graph_add_edge(gr
, blk
, blk_root(blk
));
6288 WITH_JOB_LOCK_GUARD() {
6289 for (job
= block_job_next_locked(NULL
); job
;
6290 job
= block_job_next_locked(job
)) {
6293 xdbg_graph_add_node(gr
, job
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB
,
6295 for (el
= job
->nodes
; el
; el
= el
->next
) {
6296 xdbg_graph_add_edge(gr
, job
, (BdrvChild
*)el
->data
);
6301 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
6302 xdbg_graph_add_node(gr
, bs
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_DRIVER
,
6304 QLIST_FOREACH(child
, &bs
->children
, next
) {
6305 xdbg_graph_add_edge(gr
, bs
, child
);
6309 return xdbg_graph_finalize(gr
);
6312 BlockDriverState
*bdrv_lookup_bs(const char *device
,
6313 const char *node_name
,
6317 BlockDriverState
*bs
;
6319 GLOBAL_STATE_CODE();
6322 blk
= blk_by_name(device
);
6327 error_setg(errp
, "Device '%s' has no medium", device
);
6335 bs
= bdrv_find_node(node_name
);
6342 error_setg(errp
, "Cannot find device=\'%s\' nor node-name=\'%s\'",
6343 device
? device
: "",
6344 node_name
? node_name
: "");
6348 /* If 'base' is in the same chain as 'top', return true. Otherwise,
6349 * return false. If either argument is NULL, return false. */
6350 bool bdrv_chain_contains(BlockDriverState
*top
, BlockDriverState
*base
)
6353 GLOBAL_STATE_CODE();
6355 while (top
&& top
!= base
) {
6356 top
= bdrv_filter_or_cow_bs(top
);
6362 BlockDriverState
*bdrv_next_node(BlockDriverState
*bs
)
6364 GLOBAL_STATE_CODE();
6366 return QTAILQ_FIRST(&graph_bdrv_states
);
6368 return QTAILQ_NEXT(bs
, node_list
);
6371 BlockDriverState
*bdrv_next_all_states(BlockDriverState
*bs
)
6373 GLOBAL_STATE_CODE();
6375 return QTAILQ_FIRST(&all_bdrv_states
);
6377 return QTAILQ_NEXT(bs
, bs_list
);
6380 const char *bdrv_get_node_name(const BlockDriverState
*bs
)
6383 return bs
->node_name
;
6386 const char *bdrv_get_parent_name(const BlockDriverState
*bs
)
6392 /* If multiple parents have a name, just pick the first one. */
6393 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
6394 if (c
->klass
->get_name
) {
6395 name
= c
->klass
->get_name(c
);
6396 if (name
&& *name
) {
6405 /* TODO check what callers really want: bs->node_name or blk_name() */
6406 const char *bdrv_get_device_name(const BlockDriverState
*bs
)
6409 return bdrv_get_parent_name(bs
) ?: "";
6412 /* This can be used to identify nodes that might not have a device
6413 * name associated. Since node and device names live in the same
6414 * namespace, the result is unambiguous. The exception is if both are
6415 * absent, then this returns an empty (non-null) string. */
6416 const char *bdrv_get_device_or_node_name(const BlockDriverState
*bs
)
6419 return bdrv_get_parent_name(bs
) ?: bs
->node_name
;
6422 int bdrv_get_flags(BlockDriverState
*bs
)
6425 return bs
->open_flags
;
6428 int bdrv_has_zero_init_1(BlockDriverState
*bs
)
6430 GLOBAL_STATE_CODE();
6434 int bdrv_has_zero_init(BlockDriverState
*bs
)
6436 BlockDriverState
*filtered
;
6437 GLOBAL_STATE_CODE();
6443 /* If BS is a copy on write image, it is initialized to
6444 the contents of the base image, which may not be zeroes. */
6445 if (bdrv_cow_child(bs
)) {
6448 if (bs
->drv
->bdrv_has_zero_init
) {
6449 return bs
->drv
->bdrv_has_zero_init(bs
);
6452 filtered
= bdrv_filter_bs(bs
);
6454 return bdrv_has_zero_init(filtered
);
6461 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState
*bs
)
6464 if (!(bs
->open_flags
& BDRV_O_UNMAP
)) {
6468 return bs
->supported_zero_flags
& BDRV_REQ_MAY_UNMAP
;
6471 void bdrv_get_backing_filename(BlockDriverState
*bs
,
6472 char *filename
, int filename_size
)
6475 pstrcpy(filename
, filename_size
, bs
->backing_file
);
6478 int coroutine_fn
bdrv_co_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
6481 BlockDriver
*drv
= bs
->drv
;
6483 assert_bdrv_graph_readable();
6485 /* if bs->drv == NULL, bs is closed, so there's nothing to do here */
6489 if (!drv
->bdrv_co_get_info
) {
6490 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
6492 return bdrv_co_get_info(filtered
, bdi
);
6496 memset(bdi
, 0, sizeof(*bdi
));
6497 ret
= drv
->bdrv_co_get_info(bs
, bdi
);
6498 if (bdi
->subcluster_size
== 0) {
6500 * If the driver left this unset, subclusters are not supported.
6501 * Then it is safe to treat each cluster as having only one subcluster.
6503 bdi
->subcluster_size
= bdi
->cluster_size
;
6509 if (bdi
->cluster_size
> BDRV_MAX_ALIGNMENT
) {
6516 ImageInfoSpecific
*bdrv_get_specific_info(BlockDriverState
*bs
,
6519 BlockDriver
*drv
= bs
->drv
;
6521 if (drv
&& drv
->bdrv_get_specific_info
) {
6522 return drv
->bdrv_get_specific_info(bs
, errp
);
6527 BlockStatsSpecific
*bdrv_get_specific_stats(BlockDriverState
*bs
)
6529 BlockDriver
*drv
= bs
->drv
;
6531 if (!drv
|| !drv
->bdrv_get_specific_stats
) {
6534 return drv
->bdrv_get_specific_stats(bs
);
6537 void coroutine_fn
bdrv_co_debug_event(BlockDriverState
*bs
, BlkdebugEvent event
)
6540 assert_bdrv_graph_readable();
6542 if (!bs
|| !bs
->drv
|| !bs
->drv
->bdrv_co_debug_event
) {
6546 bs
->drv
->bdrv_co_debug_event(bs
, event
);
6549 static BlockDriverState
*bdrv_find_debug_node(BlockDriverState
*bs
)
6551 GLOBAL_STATE_CODE();
6552 while (bs
&& bs
->drv
&& !bs
->drv
->bdrv_debug_breakpoint
) {
6553 bs
= bdrv_primary_bs(bs
);
6556 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_breakpoint
) {
6557 assert(bs
->drv
->bdrv_debug_remove_breakpoint
);
6564 int bdrv_debug_breakpoint(BlockDriverState
*bs
, const char *event
,
6567 GLOBAL_STATE_CODE();
6568 bs
= bdrv_find_debug_node(bs
);
6570 return bs
->drv
->bdrv_debug_breakpoint(bs
, event
, tag
);
6576 int bdrv_debug_remove_breakpoint(BlockDriverState
*bs
, const char *tag
)
6578 GLOBAL_STATE_CODE();
6579 bs
= bdrv_find_debug_node(bs
);
6581 return bs
->drv
->bdrv_debug_remove_breakpoint(bs
, tag
);
6587 int bdrv_debug_resume(BlockDriverState
*bs
, const char *tag
)
6589 GLOBAL_STATE_CODE();
6590 while (bs
&& (!bs
->drv
|| !bs
->drv
->bdrv_debug_resume
)) {
6591 bs
= bdrv_primary_bs(bs
);
6594 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_resume
) {
6595 return bs
->drv
->bdrv_debug_resume(bs
, tag
);
6601 bool bdrv_debug_is_suspended(BlockDriverState
*bs
, const char *tag
)
6603 GLOBAL_STATE_CODE();
6604 while (bs
&& bs
->drv
&& !bs
->drv
->bdrv_debug_is_suspended
) {
6605 bs
= bdrv_primary_bs(bs
);
6608 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_is_suspended
) {
6609 return bs
->drv
->bdrv_debug_is_suspended(bs
, tag
);
6615 /* backing_file can either be relative, or absolute, or a protocol. If it is
6616 * relative, it must be relative to the chain. So, passing in bs->filename
6617 * from a BDS as backing_file should not be done, as that may be relative to
6618 * the CWD rather than the chain. */
6619 BlockDriverState
*bdrv_find_backing_image(BlockDriverState
*bs
,
6620 const char *backing_file
)
6622 char *filename_full
= NULL
;
6623 char *backing_file_full
= NULL
;
6624 char *filename_tmp
= NULL
;
6625 int is_protocol
= 0;
6626 bool filenames_refreshed
= false;
6627 BlockDriverState
*curr_bs
= NULL
;
6628 BlockDriverState
*retval
= NULL
;
6629 BlockDriverState
*bs_below
;
6631 GLOBAL_STATE_CODE();
6633 if (!bs
|| !bs
->drv
|| !backing_file
) {
6637 filename_full
= g_malloc(PATH_MAX
);
6638 backing_file_full
= g_malloc(PATH_MAX
);
6640 is_protocol
= path_has_protocol(backing_file
);
6643 * Being largely a legacy function, skip any filters here
6644 * (because filters do not have normal filenames, so they cannot
6645 * match anyway; and allowing json:{} filenames is a bit out of
6648 for (curr_bs
= bdrv_skip_filters(bs
);
6649 bdrv_cow_child(curr_bs
) != NULL
;
6652 bs_below
= bdrv_backing_chain_next(curr_bs
);
6654 if (bdrv_backing_overridden(curr_bs
)) {
6656 * If the backing file was overridden, we can only compare
6657 * directly against the backing node's filename.
6660 if (!filenames_refreshed
) {
6662 * This will automatically refresh all of the
6663 * filenames in the rest of the backing chain, so we
6664 * only need to do this once.
6666 bdrv_refresh_filename(bs_below
);
6667 filenames_refreshed
= true;
6670 if (strcmp(backing_file
, bs_below
->filename
) == 0) {
6674 } else if (is_protocol
|| path_has_protocol(curr_bs
->backing_file
)) {
6676 * If either of the filename paths is actually a protocol, then
6677 * compare unmodified paths; otherwise make paths relative.
6679 char *backing_file_full_ret
;
6681 if (strcmp(backing_file
, curr_bs
->backing_file
) == 0) {
6685 /* Also check against the full backing filename for the image */
6686 backing_file_full_ret
= bdrv_get_full_backing_filename(curr_bs
,
6688 if (backing_file_full_ret
) {
6689 bool equal
= strcmp(backing_file
, backing_file_full_ret
) == 0;
6690 g_free(backing_file_full_ret
);
6697 /* If not an absolute filename path, make it relative to the current
6698 * image's filename path */
6699 filename_tmp
= bdrv_make_absolute_filename(curr_bs
, backing_file
,
6701 /* We are going to compare canonicalized absolute pathnames */
6702 if (!filename_tmp
|| !realpath(filename_tmp
, filename_full
)) {
6703 g_free(filename_tmp
);
6706 g_free(filename_tmp
);
6708 /* We need to make sure the backing filename we are comparing against
6709 * is relative to the current image filename (or absolute) */
6710 filename_tmp
= bdrv_get_full_backing_filename(curr_bs
, NULL
);
6711 if (!filename_tmp
|| !realpath(filename_tmp
, backing_file_full
)) {
6712 g_free(filename_tmp
);
6715 g_free(filename_tmp
);
6717 if (strcmp(backing_file_full
, filename_full
) == 0) {
6724 g_free(filename_full
);
6725 g_free(backing_file_full
);
6729 void bdrv_init(void)
6731 #ifdef CONFIG_BDRV_WHITELIST_TOOLS
6732 use_bdrv_whitelist
= 1;
6734 module_call_init(MODULE_INIT_BLOCK
);
6737 void bdrv_init_with_whitelist(void)
6739 use_bdrv_whitelist
= 1;
6743 int bdrv_activate(BlockDriverState
*bs
, Error
**errp
)
6745 BdrvChild
*child
, *parent
;
6746 Error
*local_err
= NULL
;
6748 BdrvDirtyBitmap
*bm
;
6750 GLOBAL_STATE_CODE();
6756 QLIST_FOREACH(child
, &bs
->children
, next
) {
6757 bdrv_activate(child
->bs
, &local_err
);
6759 error_propagate(errp
, local_err
);
6765 * Update permissions, they may differ for inactive nodes.
6767 * Note that the required permissions of inactive images are always a
6768 * subset of the permissions required after activating the image. This
6769 * allows us to just get the permissions upfront without restricting
6770 * bdrv_co_invalidate_cache().
6772 * It also means that in error cases, we don't have to try and revert to
6773 * the old permissions (which is an operation that could fail, too). We can
6774 * just keep the extended permissions for the next time that an activation
6775 * of the image is tried.
6777 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
6778 bs
->open_flags
&= ~BDRV_O_INACTIVE
;
6779 ret
= bdrv_refresh_perms(bs
, NULL
, errp
);
6781 bs
->open_flags
|= BDRV_O_INACTIVE
;
6785 ret
= bdrv_invalidate_cache(bs
, errp
);
6787 bs
->open_flags
|= BDRV_O_INACTIVE
;
6791 FOR_EACH_DIRTY_BITMAP(bs
, bm
) {
6792 bdrv_dirty_bitmap_skip_store(bm
, false);
6795 ret
= bdrv_refresh_total_sectors(bs
, bs
->total_sectors
);
6797 bs
->open_flags
|= BDRV_O_INACTIVE
;
6798 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
6803 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6804 if (parent
->klass
->activate
) {
6805 parent
->klass
->activate(parent
, &local_err
);
6807 bs
->open_flags
|= BDRV_O_INACTIVE
;
6808 error_propagate(errp
, local_err
);
6817 int coroutine_fn
bdrv_co_invalidate_cache(BlockDriverState
*bs
, Error
**errp
)
6819 Error
*local_err
= NULL
;
6822 assert(!(bs
->open_flags
& BDRV_O_INACTIVE
));
6823 assert_bdrv_graph_readable();
6825 if (bs
->drv
->bdrv_co_invalidate_cache
) {
6826 bs
->drv
->bdrv_co_invalidate_cache(bs
, &local_err
);
6828 error_propagate(errp
, local_err
);
6836 void bdrv_activate_all(Error
**errp
)
6838 BlockDriverState
*bs
;
6839 BdrvNextIterator it
;
6841 GLOBAL_STATE_CODE();
6843 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
6844 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
6847 aio_context_acquire(aio_context
);
6848 ret
= bdrv_activate(bs
, errp
);
6849 aio_context_release(aio_context
);
6851 bdrv_next_cleanup(&it
);
6857 static bool bdrv_has_bds_parent(BlockDriverState
*bs
, bool only_active
)
6860 GLOBAL_STATE_CODE();
6862 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6863 if (parent
->klass
->parent_is_bds
) {
6864 BlockDriverState
*parent_bs
= parent
->opaque
;
6865 if (!only_active
|| !(parent_bs
->open_flags
& BDRV_O_INACTIVE
)) {
6874 static int bdrv_inactivate_recurse(BlockDriverState
*bs
)
6876 BdrvChild
*child
, *parent
;
6878 uint64_t cumulative_perms
, cumulative_shared_perms
;
6880 GLOBAL_STATE_CODE();
6886 /* Make sure that we don't inactivate a child before its parent.
6887 * It will be covered by recursion from the yet active parent. */
6888 if (bdrv_has_bds_parent(bs
, true)) {
6892 assert(!(bs
->open_flags
& BDRV_O_INACTIVE
));
6894 /* Inactivate this node */
6895 if (bs
->drv
->bdrv_inactivate
) {
6896 ret
= bs
->drv
->bdrv_inactivate(bs
);
6902 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6903 if (parent
->klass
->inactivate
) {
6904 ret
= parent
->klass
->inactivate(parent
);
6911 bdrv_get_cumulative_perm(bs
, &cumulative_perms
,
6912 &cumulative_shared_perms
);
6913 if (cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) {
6914 /* Our inactive parents still need write access. Inactivation failed. */
6918 bs
->open_flags
|= BDRV_O_INACTIVE
;
6921 * Update permissions, they may differ for inactive nodes.
6922 * We only tried to loosen restrictions, so errors are not fatal, ignore
6925 bdrv_refresh_perms(bs
, NULL
, NULL
);
6927 /* Recursively inactivate children */
6928 QLIST_FOREACH(child
, &bs
->children
, next
) {
6929 ret
= bdrv_inactivate_recurse(child
->bs
);
6938 int bdrv_inactivate_all(void)
6940 BlockDriverState
*bs
= NULL
;
6941 BdrvNextIterator it
;
6943 GSList
*aio_ctxs
= NULL
, *ctx
;
6945 GLOBAL_STATE_CODE();
6947 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
6948 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
6950 if (!g_slist_find(aio_ctxs
, aio_context
)) {
6951 aio_ctxs
= g_slist_prepend(aio_ctxs
, aio_context
);
6952 aio_context_acquire(aio_context
);
6956 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
6957 /* Nodes with BDS parents are covered by recursion from the last
6958 * parent that gets inactivated. Don't inactivate them a second
6959 * time if that has already happened. */
6960 if (bdrv_has_bds_parent(bs
, false)) {
6963 ret
= bdrv_inactivate_recurse(bs
);
6965 bdrv_next_cleanup(&it
);
6971 for (ctx
= aio_ctxs
; ctx
!= NULL
; ctx
= ctx
->next
) {
6972 AioContext
*aio_context
= ctx
->data
;
6973 aio_context_release(aio_context
);
6975 g_slist_free(aio_ctxs
);
6980 /**************************************************************/
6981 /* removable device support */
6984 * Return TRUE if the media is present
6986 bool coroutine_fn
bdrv_co_is_inserted(BlockDriverState
*bs
)
6988 BlockDriver
*drv
= bs
->drv
;
6991 assert_bdrv_graph_readable();
6996 if (drv
->bdrv_co_is_inserted
) {
6997 return drv
->bdrv_co_is_inserted(bs
);
6999 QLIST_FOREACH(child
, &bs
->children
, next
) {
7000 if (!bdrv_co_is_inserted(child
->bs
)) {
7008 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
7010 void coroutine_fn
bdrv_co_eject(BlockDriverState
*bs
, bool eject_flag
)
7012 BlockDriver
*drv
= bs
->drv
;
7014 assert_bdrv_graph_readable();
7016 if (drv
&& drv
->bdrv_co_eject
) {
7017 drv
->bdrv_co_eject(bs
, eject_flag
);
7022 * Lock or unlock the media (if it is locked, the user won't be able
7023 * to eject it manually).
7025 void coroutine_fn
bdrv_co_lock_medium(BlockDriverState
*bs
, bool locked
)
7027 BlockDriver
*drv
= bs
->drv
;
7029 assert_bdrv_graph_readable();
7030 trace_bdrv_lock_medium(bs
, locked
);
7032 if (drv
&& drv
->bdrv_co_lock_medium
) {
7033 drv
->bdrv_co_lock_medium(bs
, locked
);
7037 /* Get a reference to bs */
7038 void bdrv_ref(BlockDriverState
*bs
)
7040 GLOBAL_STATE_CODE();
7044 /* Release a previously grabbed reference to bs.
7045 * If after releasing, reference count is zero, the BlockDriverState is
7047 void bdrv_unref(BlockDriverState
*bs
)
7049 GLOBAL_STATE_CODE();
7053 assert(bs
->refcnt
> 0);
7054 if (--bs
->refcnt
== 0) {
7060 * Release a BlockDriverState reference while holding the graph write lock.
7062 * Calling bdrv_unref() directly is forbidden while holding the graph lock
7063 * because bdrv_close() both involves polling and taking the graph lock
7064 * internally. bdrv_schedule_unref() instead delays decreasing the refcount and
7065 * possibly closing @bs until the graph lock is released.
7067 void bdrv_schedule_unref(BlockDriverState
*bs
)
7072 aio_bh_schedule_oneshot(qemu_get_aio_context(),
7073 (QEMUBHFunc
*) bdrv_unref
, bs
);
7076 struct BdrvOpBlocker
{
7078 QLIST_ENTRY(BdrvOpBlocker
) list
;
7081 bool bdrv_op_is_blocked(BlockDriverState
*bs
, BlockOpType op
, Error
**errp
)
7083 BdrvOpBlocker
*blocker
;
7084 GLOBAL_STATE_CODE();
7085 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
7086 if (!QLIST_EMPTY(&bs
->op_blockers
[op
])) {
7087 blocker
= QLIST_FIRST(&bs
->op_blockers
[op
]);
7088 error_propagate_prepend(errp
, error_copy(blocker
->reason
),
7089 "Node '%s' is busy: ",
7090 bdrv_get_device_or_node_name(bs
));
7096 void bdrv_op_block(BlockDriverState
*bs
, BlockOpType op
, Error
*reason
)
7098 BdrvOpBlocker
*blocker
;
7099 GLOBAL_STATE_CODE();
7100 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
7102 blocker
= g_new0(BdrvOpBlocker
, 1);
7103 blocker
->reason
= reason
;
7104 QLIST_INSERT_HEAD(&bs
->op_blockers
[op
], blocker
, list
);
7107 void bdrv_op_unblock(BlockDriverState
*bs
, BlockOpType op
, Error
*reason
)
7109 BdrvOpBlocker
*blocker
, *next
;
7110 GLOBAL_STATE_CODE();
7111 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
7112 QLIST_FOREACH_SAFE(blocker
, &bs
->op_blockers
[op
], list
, next
) {
7113 if (blocker
->reason
== reason
) {
7114 QLIST_REMOVE(blocker
, list
);
7120 void bdrv_op_block_all(BlockDriverState
*bs
, Error
*reason
)
7123 GLOBAL_STATE_CODE();
7124 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
7125 bdrv_op_block(bs
, i
, reason
);
7129 void bdrv_op_unblock_all(BlockDriverState
*bs
, Error
*reason
)
7132 GLOBAL_STATE_CODE();
7133 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
7134 bdrv_op_unblock(bs
, i
, reason
);
7138 bool bdrv_op_blocker_is_empty(BlockDriverState
*bs
)
7141 GLOBAL_STATE_CODE();
7142 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
7143 if (!QLIST_EMPTY(&bs
->op_blockers
[i
])) {
7151 * Must not be called while holding the lock of an AioContext other than the
7154 void bdrv_img_create(const char *filename
, const char *fmt
,
7155 const char *base_filename
, const char *base_fmt
,
7156 char *options
, uint64_t img_size
, int flags
, bool quiet
,
7159 QemuOptsList
*create_opts
= NULL
;
7160 QemuOpts
*opts
= NULL
;
7161 const char *backing_fmt
, *backing_file
;
7163 BlockDriver
*drv
, *proto_drv
;
7164 Error
*local_err
= NULL
;
7167 GLOBAL_STATE_CODE();
7169 /* Find driver and parse its options */
7170 drv
= bdrv_find_format(fmt
);
7172 error_setg(errp
, "Unknown file format '%s'", fmt
);
7176 proto_drv
= bdrv_find_protocol(filename
, true, errp
);
7181 if (!drv
->create_opts
) {
7182 error_setg(errp
, "Format driver '%s' does not support image creation",
7187 if (!proto_drv
->create_opts
) {
7188 error_setg(errp
, "Protocol driver '%s' does not support image creation",
7189 proto_drv
->format_name
);
7193 aio_context_acquire(qemu_get_aio_context());
7195 /* Create parameter list */
7196 create_opts
= qemu_opts_append(create_opts
, drv
->create_opts
);
7197 create_opts
= qemu_opts_append(create_opts
, proto_drv
->create_opts
);
7199 opts
= qemu_opts_create(create_opts
, NULL
, 0, &error_abort
);
7201 /* Parse -o options */
7203 if (!qemu_opts_do_parse(opts
, options
, NULL
, errp
)) {
7208 if (!qemu_opt_get(opts
, BLOCK_OPT_SIZE
)) {
7209 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, img_size
, &error_abort
);
7210 } else if (img_size
!= UINT64_C(-1)) {
7211 error_setg(errp
, "The image size must be specified only once");
7215 if (base_filename
) {
7216 if (!qemu_opt_set(opts
, BLOCK_OPT_BACKING_FILE
, base_filename
,
7218 error_setg(errp
, "Backing file not supported for file format '%s'",
7225 if (!qemu_opt_set(opts
, BLOCK_OPT_BACKING_FMT
, base_fmt
, NULL
)) {
7226 error_setg(errp
, "Backing file format not supported for file "
7227 "format '%s'", fmt
);
7232 backing_file
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FILE
);
7234 if (!strcmp(filename
, backing_file
)) {
7235 error_setg(errp
, "Error: Trying to create an image with the "
7236 "same filename as the backing file");
7239 if (backing_file
[0] == '\0') {
7240 error_setg(errp
, "Expected backing file name, got empty string");
7245 backing_fmt
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FMT
);
7247 /* The size for the image must always be specified, unless we have a backing
7248 * file and we have not been forbidden from opening it. */
7249 size
= qemu_opt_get_size(opts
, BLOCK_OPT_SIZE
, img_size
);
7250 if (backing_file
&& !(flags
& BDRV_O_NO_BACKING
)) {
7251 BlockDriverState
*bs
;
7254 QDict
*backing_options
= NULL
;
7257 bdrv_get_full_backing_filename_from_filename(filename
, backing_file
,
7262 assert(full_backing
);
7265 * No need to do I/O here, which allows us to open encrypted
7266 * backing images without needing the secret
7269 back_flags
&= ~(BDRV_O_RDWR
| BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
);
7270 back_flags
|= BDRV_O_NO_IO
;
7272 backing_options
= qdict_new();
7274 qdict_put_str(backing_options
, "driver", backing_fmt
);
7276 qdict_put_bool(backing_options
, BDRV_OPT_FORCE_SHARE
, true);
7278 bs
= bdrv_open(full_backing
, NULL
, backing_options
, back_flags
,
7280 g_free(full_backing
);
7282 error_append_hint(&local_err
, "Could not open backing image.\n");
7286 error_setg(&local_err
,
7287 "Backing file specified without backing format");
7288 error_append_hint(&local_err
, "Detected format of %s.\n",
7289 bs
->drv
->format_name
);
7293 /* Opened BS, have no size */
7294 size
= bdrv_getlength(bs
);
7296 error_setg_errno(errp
, -size
, "Could not get size of '%s'",
7301 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, size
, &error_abort
);
7305 /* (backing_file && !(flags & BDRV_O_NO_BACKING)) */
7306 } else if (backing_file
&& !backing_fmt
) {
7307 error_setg(&local_err
,
7308 "Backing file specified without backing format");
7313 error_setg(errp
, "Image creation needs a size parameter");
7318 printf("Formatting '%s', fmt=%s ", filename
, fmt
);
7319 qemu_opts_print(opts
, " ");
7324 ret
= bdrv_create(drv
, filename
, opts
, &local_err
);
7326 if (ret
== -EFBIG
) {
7327 /* This is generally a better message than whatever the driver would
7328 * deliver (especially because of the cluster_size_hint), since that
7329 * is most probably not much different from "image too large". */
7330 const char *cluster_size_hint
= "";
7331 if (qemu_opt_get_size(opts
, BLOCK_OPT_CLUSTER_SIZE
, 0)) {
7332 cluster_size_hint
= " (try using a larger cluster size)";
7334 error_setg(errp
, "The image size is too large for file format '%s'"
7335 "%s", fmt
, cluster_size_hint
);
7336 error_free(local_err
);
7341 qemu_opts_del(opts
);
7342 qemu_opts_free(create_opts
);
7343 error_propagate(errp
, local_err
);
7344 aio_context_release(qemu_get_aio_context());
7347 AioContext
*bdrv_get_aio_context(BlockDriverState
*bs
)
7350 return bs
? bs
->aio_context
: qemu_get_aio_context();
7353 AioContext
*coroutine_fn
bdrv_co_enter(BlockDriverState
*bs
)
7355 Coroutine
*self
= qemu_coroutine_self();
7356 AioContext
*old_ctx
= qemu_coroutine_get_aio_context(self
);
7357 AioContext
*new_ctx
;
7361 * Increase bs->in_flight to ensure that this operation is completed before
7362 * moving the node to a different AioContext. Read new_ctx only afterwards.
7364 bdrv_inc_in_flight(bs
);
7366 new_ctx
= bdrv_get_aio_context(bs
);
7367 aio_co_reschedule_self(new_ctx
);
7371 void coroutine_fn
bdrv_co_leave(BlockDriverState
*bs
, AioContext
*old_ctx
)
7374 aio_co_reschedule_self(old_ctx
);
7375 bdrv_dec_in_flight(bs
);
7378 void coroutine_fn
bdrv_co_lock(BlockDriverState
*bs
)
7380 AioContext
*ctx
= bdrv_get_aio_context(bs
);
7382 /* In the main thread, bs->aio_context won't change concurrently */
7383 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
7386 * We're in coroutine context, so we already hold the lock of the main
7387 * loop AioContext. Don't lock it twice to avoid deadlocks.
7389 assert(qemu_in_coroutine());
7390 if (ctx
!= qemu_get_aio_context()) {
7391 aio_context_acquire(ctx
);
7395 void coroutine_fn
bdrv_co_unlock(BlockDriverState
*bs
)
7397 AioContext
*ctx
= bdrv_get_aio_context(bs
);
7399 assert(qemu_in_coroutine());
7400 if (ctx
!= qemu_get_aio_context()) {
7401 aio_context_release(ctx
);
7405 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier
*ban
)
7407 GLOBAL_STATE_CODE();
7408 QLIST_REMOVE(ban
, list
);
7412 static void bdrv_detach_aio_context(BlockDriverState
*bs
)
7414 BdrvAioNotifier
*baf
, *baf_tmp
;
7416 assert(!bs
->walking_aio_notifiers
);
7417 GLOBAL_STATE_CODE();
7418 bs
->walking_aio_notifiers
= true;
7419 QLIST_FOREACH_SAFE(baf
, &bs
->aio_notifiers
, list
, baf_tmp
) {
7421 bdrv_do_remove_aio_context_notifier(baf
);
7423 baf
->detach_aio_context(baf
->opaque
);
7426 /* Never mind iterating again to check for ->deleted. bdrv_close() will
7427 * remove remaining aio notifiers if we aren't called again.
7429 bs
->walking_aio_notifiers
= false;
7431 if (bs
->drv
&& bs
->drv
->bdrv_detach_aio_context
) {
7432 bs
->drv
->bdrv_detach_aio_context(bs
);
7435 bs
->aio_context
= NULL
;
7438 static void bdrv_attach_aio_context(BlockDriverState
*bs
,
7439 AioContext
*new_context
)
7441 BdrvAioNotifier
*ban
, *ban_tmp
;
7442 GLOBAL_STATE_CODE();
7444 bs
->aio_context
= new_context
;
7446 if (bs
->drv
&& bs
->drv
->bdrv_attach_aio_context
) {
7447 bs
->drv
->bdrv_attach_aio_context(bs
, new_context
);
7450 assert(!bs
->walking_aio_notifiers
);
7451 bs
->walking_aio_notifiers
= true;
7452 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_tmp
) {
7454 bdrv_do_remove_aio_context_notifier(ban
);
7456 ban
->attached_aio_context(new_context
, ban
->opaque
);
7459 bs
->walking_aio_notifiers
= false;
7462 typedef struct BdrvStateSetAioContext
{
7463 AioContext
*new_ctx
;
7464 BlockDriverState
*bs
;
7465 } BdrvStateSetAioContext
;
7467 static bool bdrv_parent_change_aio_context(BdrvChild
*c
, AioContext
*ctx
,
7468 GHashTable
*visited
,
7472 GLOBAL_STATE_CODE();
7473 if (g_hash_table_contains(visited
, c
)) {
7476 g_hash_table_add(visited
, c
);
7479 * A BdrvChildClass that doesn't handle AioContext changes cannot
7480 * tolerate any AioContext changes
7482 if (!c
->klass
->change_aio_ctx
) {
7483 char *user
= bdrv_child_user_desc(c
);
7484 error_setg(errp
, "Changing iothreads is not supported by %s", user
);
7488 if (!c
->klass
->change_aio_ctx(c
, ctx
, visited
, tran
, errp
)) {
7489 assert(!errp
|| *errp
);
7495 bool bdrv_child_change_aio_context(BdrvChild
*c
, AioContext
*ctx
,
7496 GHashTable
*visited
, Transaction
*tran
,
7499 GLOBAL_STATE_CODE();
7500 if (g_hash_table_contains(visited
, c
)) {
7503 g_hash_table_add(visited
, c
);
7504 return bdrv_change_aio_context(c
->bs
, ctx
, visited
, tran
, errp
);
7507 static void bdrv_set_aio_context_clean(void *opaque
)
7509 BdrvStateSetAioContext
*state
= (BdrvStateSetAioContext
*) opaque
;
7510 BlockDriverState
*bs
= (BlockDriverState
*) state
->bs
;
7512 /* Paired with bdrv_drained_begin in bdrv_change_aio_context() */
7513 bdrv_drained_end(bs
);
7518 static void bdrv_set_aio_context_commit(void *opaque
)
7520 BdrvStateSetAioContext
*state
= (BdrvStateSetAioContext
*) opaque
;
7521 BlockDriverState
*bs
= (BlockDriverState
*) state
->bs
;
7522 AioContext
*new_context
= state
->new_ctx
;
7523 AioContext
*old_context
= bdrv_get_aio_context(bs
);
7526 * Take the old AioContex when detaching it from bs.
7527 * At this point, new_context lock is already acquired, and we are now
7528 * also taking old_context. This is safe as long as bdrv_detach_aio_context
7529 * does not call AIO_POLL_WHILE().
7531 if (old_context
!= qemu_get_aio_context()) {
7532 aio_context_acquire(old_context
);
7534 bdrv_detach_aio_context(bs
);
7535 if (old_context
!= qemu_get_aio_context()) {
7536 aio_context_release(old_context
);
7538 bdrv_attach_aio_context(bs
, new_context
);
7541 static TransactionActionDrv set_aio_context
= {
7542 .commit
= bdrv_set_aio_context_commit
,
7543 .clean
= bdrv_set_aio_context_clean
,
7547 * Changes the AioContext used for fd handlers, timers, and BHs by this
7548 * BlockDriverState and all its children and parents.
7550 * Must be called from the main AioContext.
7552 * The caller must own the AioContext lock for the old AioContext of bs, but it
7553 * must not own the AioContext lock for new_context (unless new_context is the
7554 * same as the current context of bs).
7556 * @visited will accumulate all visited BdrvChild objects. The caller is
7557 * responsible for freeing the list afterwards.
7559 static bool bdrv_change_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
7560 GHashTable
*visited
, Transaction
*tran
,
7564 BdrvStateSetAioContext
*state
;
7566 GLOBAL_STATE_CODE();
7568 if (bdrv_get_aio_context(bs
) == ctx
) {
7572 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
7573 if (!bdrv_parent_change_aio_context(c
, ctx
, visited
, tran
, errp
)) {
7578 QLIST_FOREACH(c
, &bs
->children
, next
) {
7579 if (!bdrv_child_change_aio_context(c
, ctx
, visited
, tran
, errp
)) {
7584 state
= g_new(BdrvStateSetAioContext
, 1);
7585 *state
= (BdrvStateSetAioContext
) {
7590 /* Paired with bdrv_drained_end in bdrv_set_aio_context_clean() */
7591 bdrv_drained_begin(bs
);
7593 tran_add(tran
, &set_aio_context
, state
);
7599 * Change bs's and recursively all of its parents' and children's AioContext
7600 * to the given new context, returning an error if that isn't possible.
7602 * If ignore_child is not NULL, that child (and its subgraph) will not
7605 * This function still requires the caller to take the bs current
7606 * AioContext lock, otherwise draining will fail since AIO_WAIT_WHILE
7607 * assumes the lock is always held if bs is in another AioContext.
7608 * For the same reason, it temporarily also holds the new AioContext, since
7609 * bdrv_drained_end calls BDRV_POLL_WHILE that assumes the lock is taken too.
7610 * Therefore the new AioContext lock must not be taken by the caller.
7612 int bdrv_try_change_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
7613 BdrvChild
*ignore_child
, Error
**errp
)
7616 GHashTable
*visited
;
7618 AioContext
*old_context
= bdrv_get_aio_context(bs
);
7619 GLOBAL_STATE_CODE();
7622 * Recursion phase: go through all nodes of the graph.
7623 * Take care of checking that all nodes support changing AioContext
7624 * and drain them, building a linear list of callbacks to run if everything
7625 * is successful (the transaction itself).
7628 visited
= g_hash_table_new(NULL
, NULL
);
7630 g_hash_table_add(visited
, ignore_child
);
7632 ret
= bdrv_change_aio_context(bs
, ctx
, visited
, tran
, errp
);
7633 g_hash_table_destroy(visited
);
7636 * Linear phase: go through all callbacks collected in the transaction.
7637 * Run all callbacks collected in the recursion to switch all nodes
7638 * AioContext lock (transaction commit), or undo all changes done in the
7639 * recursion (transaction abort).
7643 /* Just run clean() callbacks. No AioContext changed. */
7649 * Release old AioContext, it won't be needed anymore, as all
7650 * bdrv_drained_begin() have been called already.
7652 if (qemu_get_aio_context() != old_context
) {
7653 aio_context_release(old_context
);
7657 * Acquire new AioContext since bdrv_drained_end() is going to be called
7658 * after we switched all nodes in the new AioContext, and the function
7659 * assumes that the lock of the bs is always taken.
7661 if (qemu_get_aio_context() != ctx
) {
7662 aio_context_acquire(ctx
);
7667 if (qemu_get_aio_context() != ctx
) {
7668 aio_context_release(ctx
);
7671 /* Re-acquire the old AioContext, since the caller takes and releases it. */
7672 if (qemu_get_aio_context() != old_context
) {
7673 aio_context_acquire(old_context
);
7679 void bdrv_add_aio_context_notifier(BlockDriverState
*bs
,
7680 void (*attached_aio_context
)(AioContext
*new_context
, void *opaque
),
7681 void (*detach_aio_context
)(void *opaque
), void *opaque
)
7683 BdrvAioNotifier
*ban
= g_new(BdrvAioNotifier
, 1);
7684 *ban
= (BdrvAioNotifier
){
7685 .attached_aio_context
= attached_aio_context
,
7686 .detach_aio_context
= detach_aio_context
,
7689 GLOBAL_STATE_CODE();
7691 QLIST_INSERT_HEAD(&bs
->aio_notifiers
, ban
, list
);
7694 void bdrv_remove_aio_context_notifier(BlockDriverState
*bs
,
7695 void (*attached_aio_context
)(AioContext
*,
7697 void (*detach_aio_context
)(void *),
7700 BdrvAioNotifier
*ban
, *ban_next
;
7701 GLOBAL_STATE_CODE();
7703 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_next
) {
7704 if (ban
->attached_aio_context
== attached_aio_context
&&
7705 ban
->detach_aio_context
== detach_aio_context
&&
7706 ban
->opaque
== opaque
&&
7707 ban
->deleted
== false)
7709 if (bs
->walking_aio_notifiers
) {
7710 ban
->deleted
= true;
7712 bdrv_do_remove_aio_context_notifier(ban
);
7721 int bdrv_amend_options(BlockDriverState
*bs
, QemuOpts
*opts
,
7722 BlockDriverAmendStatusCB
*status_cb
, void *cb_opaque
,
7726 GLOBAL_STATE_CODE();
7728 error_setg(errp
, "Node is ejected");
7731 if (!bs
->drv
->bdrv_amend_options
) {
7732 error_setg(errp
, "Block driver '%s' does not support option amendment",
7733 bs
->drv
->format_name
);
7736 return bs
->drv
->bdrv_amend_options(bs
, opts
, status_cb
,
7737 cb_opaque
, force
, errp
);
7741 * This function checks whether the given @to_replace is allowed to be
7742 * replaced by a node that always shows the same data as @bs. This is
7743 * used for example to verify whether the mirror job can replace
7744 * @to_replace by the target mirrored from @bs.
7745 * To be replaceable, @bs and @to_replace may either be guaranteed to
7746 * always show the same data (because they are only connected through
7747 * filters), or some driver may allow replacing one of its children
7748 * because it can guarantee that this child's data is not visible at
7749 * all (for example, for dissenting quorum children that have no other
7752 bool bdrv_recurse_can_replace(BlockDriverState
*bs
,
7753 BlockDriverState
*to_replace
)
7755 BlockDriverState
*filtered
;
7757 GLOBAL_STATE_CODE();
7759 if (!bs
|| !bs
->drv
) {
7763 if (bs
== to_replace
) {
7767 /* See what the driver can do */
7768 if (bs
->drv
->bdrv_recurse_can_replace
) {
7769 return bs
->drv
->bdrv_recurse_can_replace(bs
, to_replace
);
7772 /* For filters without an own implementation, we can recurse on our own */
7773 filtered
= bdrv_filter_bs(bs
);
7775 return bdrv_recurse_can_replace(filtered
, to_replace
);
7783 * Check whether the given @node_name can be replaced by a node that
7784 * has the same data as @parent_bs. If so, return @node_name's BDS;
7787 * @node_name must be a (recursive) *child of @parent_bs (or this
7788 * function will return NULL).
7790 * The result (whether the node can be replaced or not) is only valid
7791 * for as long as no graph or permission changes occur.
7793 BlockDriverState
*check_to_replace_node(BlockDriverState
*parent_bs
,
7794 const char *node_name
, Error
**errp
)
7796 BlockDriverState
*to_replace_bs
= bdrv_find_node(node_name
);
7797 AioContext
*aio_context
;
7799 GLOBAL_STATE_CODE();
7801 if (!to_replace_bs
) {
7802 error_setg(errp
, "Failed to find node with node-name='%s'", node_name
);
7806 aio_context
= bdrv_get_aio_context(to_replace_bs
);
7807 aio_context_acquire(aio_context
);
7809 if (bdrv_op_is_blocked(to_replace_bs
, BLOCK_OP_TYPE_REPLACE
, errp
)) {
7810 to_replace_bs
= NULL
;
7814 /* We don't want arbitrary node of the BDS chain to be replaced only the top
7815 * most non filter in order to prevent data corruption.
7816 * Another benefit is that this tests exclude backing files which are
7817 * blocked by the backing blockers.
7819 if (!bdrv_recurse_can_replace(parent_bs
, to_replace_bs
)) {
7820 error_setg(errp
, "Cannot replace '%s' by a node mirrored from '%s', "
7821 "because it cannot be guaranteed that doing so would not "
7822 "lead to an abrupt change of visible data",
7823 node_name
, parent_bs
->node_name
);
7824 to_replace_bs
= NULL
;
7829 aio_context_release(aio_context
);
7830 return to_replace_bs
;
7834 * Iterates through the list of runtime option keys that are said to
7835 * be "strong" for a BDS. An option is called "strong" if it changes
7836 * a BDS's data. For example, the null block driver's "size" and
7837 * "read-zeroes" options are strong, but its "latency-ns" option is
7840 * If a key returned by this function ends with a dot, all options
7841 * starting with that prefix are strong.
7843 static const char *const *strong_options(BlockDriverState
*bs
,
7844 const char *const *curopt
)
7846 static const char *const global_options
[] = {
7847 "driver", "filename", NULL
7851 return &global_options
[0];
7855 if (curopt
== &global_options
[ARRAY_SIZE(global_options
) - 1] && bs
->drv
) {
7856 curopt
= bs
->drv
->strong_runtime_opts
;
7859 return (curopt
&& *curopt
) ? curopt
: NULL
;
7863 * Copies all strong runtime options from bs->options to the given
7864 * QDict. The set of strong option keys is determined by invoking
7867 * Returns true iff any strong option was present in bs->options (and
7868 * thus copied to the target QDict) with the exception of "filename"
7869 * and "driver". The caller is expected to use this value to decide
7870 * whether the existence of strong options prevents the generation of
7873 static bool append_strong_runtime_options(QDict
*d
, BlockDriverState
*bs
)
7875 bool found_any
= false;
7876 const char *const *option_name
= NULL
;
7882 while ((option_name
= strong_options(bs
, option_name
))) {
7883 bool option_given
= false;
7885 assert(strlen(*option_name
) > 0);
7886 if ((*option_name
)[strlen(*option_name
) - 1] != '.') {
7887 QObject
*entry
= qdict_get(bs
->options
, *option_name
);
7892 qdict_put_obj(d
, *option_name
, qobject_ref(entry
));
7893 option_given
= true;
7895 const QDictEntry
*entry
;
7896 for (entry
= qdict_first(bs
->options
); entry
;
7897 entry
= qdict_next(bs
->options
, entry
))
7899 if (strstart(qdict_entry_key(entry
), *option_name
, NULL
)) {
7900 qdict_put_obj(d
, qdict_entry_key(entry
),
7901 qobject_ref(qdict_entry_value(entry
)));
7902 option_given
= true;
7907 /* While "driver" and "filename" need to be included in a JSON filename,
7908 * their existence does not prohibit generation of a plain filename. */
7909 if (!found_any
&& option_given
&&
7910 strcmp(*option_name
, "driver") && strcmp(*option_name
, "filename"))
7916 if (!qdict_haskey(d
, "driver")) {
7917 /* Drivers created with bdrv_new_open_driver() may not have a
7918 * @driver option. Add it here. */
7919 qdict_put_str(d
, "driver", bs
->drv
->format_name
);
7925 /* Note: This function may return false positives; it may return true
7926 * even if opening the backing file specified by bs's image header
7927 * would result in exactly bs->backing. */
7928 static bool bdrv_backing_overridden(BlockDriverState
*bs
)
7930 GLOBAL_STATE_CODE();
7932 return strcmp(bs
->auto_backing_file
,
7933 bs
->backing
->bs
->filename
);
7935 /* No backing BDS, so if the image header reports any backing
7936 * file, it must have been suppressed */
7937 return bs
->auto_backing_file
[0] != '\0';
7941 /* Updates the following BDS fields:
7942 * - exact_filename: A filename which may be used for opening a block device
7943 * which (mostly) equals the given BDS (even without any
7944 * other options; so reading and writing must return the same
7945 * results, but caching etc. may be different)
7946 * - full_open_options: Options which, when given when opening a block device
7947 * (without a filename), result in a BDS (mostly)
7948 * equalling the given one
7949 * - filename: If exact_filename is set, it is copied here. Otherwise,
7950 * full_open_options is converted to a JSON object, prefixed with
7951 * "json:" (for use through the JSON pseudo protocol) and put here.
7953 void bdrv_refresh_filename(BlockDriverState
*bs
)
7955 BlockDriver
*drv
= bs
->drv
;
7957 BlockDriverState
*primary_child_bs
;
7959 bool backing_overridden
;
7960 bool generate_json_filename
; /* Whether our default implementation should
7961 fill exact_filename (false) or not (true) */
7963 GLOBAL_STATE_CODE();
7969 /* This BDS's file name may depend on any of its children's file names, so
7970 * refresh those first */
7971 QLIST_FOREACH(child
, &bs
->children
, next
) {
7972 bdrv_refresh_filename(child
->bs
);
7976 /* For implicit nodes, just copy everything from the single child */
7977 child
= QLIST_FIRST(&bs
->children
);
7978 assert(QLIST_NEXT(child
, next
) == NULL
);
7980 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
),
7981 child
->bs
->exact_filename
);
7982 pstrcpy(bs
->filename
, sizeof(bs
->filename
), child
->bs
->filename
);
7984 qobject_unref(bs
->full_open_options
);
7985 bs
->full_open_options
= qobject_ref(child
->bs
->full_open_options
);
7990 backing_overridden
= bdrv_backing_overridden(bs
);
7992 if (bs
->open_flags
& BDRV_O_NO_IO
) {
7993 /* Without I/O, the backing file does not change anything.
7994 * Therefore, in such a case (primarily qemu-img), we can
7995 * pretend the backing file has not been overridden even if
7996 * it technically has been. */
7997 backing_overridden
= false;
8000 /* Gather the options QDict */
8002 generate_json_filename
= append_strong_runtime_options(opts
, bs
);
8003 generate_json_filename
|= backing_overridden
;
8005 if (drv
->bdrv_gather_child_options
) {
8006 /* Some block drivers may not want to present all of their children's
8007 * options, or name them differently from BdrvChild.name */
8008 drv
->bdrv_gather_child_options(bs
, opts
, backing_overridden
);
8010 QLIST_FOREACH(child
, &bs
->children
, next
) {
8011 if (child
== bs
->backing
&& !backing_overridden
) {
8012 /* We can skip the backing BDS if it has not been overridden */
8016 qdict_put(opts
, child
->name
,
8017 qobject_ref(child
->bs
->full_open_options
));
8020 if (backing_overridden
&& !bs
->backing
) {
8021 /* Force no backing file */
8022 qdict_put_null(opts
, "backing");
8026 qobject_unref(bs
->full_open_options
);
8027 bs
->full_open_options
= opts
;
8029 primary_child_bs
= bdrv_primary_bs(bs
);
8031 if (drv
->bdrv_refresh_filename
) {
8032 /* Obsolete information is of no use here, so drop the old file name
8033 * information before refreshing it */
8034 bs
->exact_filename
[0] = '\0';
8036 drv
->bdrv_refresh_filename(bs
);
8037 } else if (primary_child_bs
) {
8039 * Try to reconstruct valid information from the underlying
8040 * file -- this only works for format nodes (filter nodes
8041 * cannot be probed and as such must be selected by the user
8042 * either through an options dict, or through a special
8043 * filename which the filter driver must construct in its
8044 * .bdrv_refresh_filename() implementation).
8047 bs
->exact_filename
[0] = '\0';
8050 * We can use the underlying file's filename if:
8051 * - it has a filename,
8052 * - the current BDS is not a filter,
8053 * - the file is a protocol BDS, and
8054 * - opening that file (as this BDS's format) will automatically create
8055 * the BDS tree we have right now, that is:
8056 * - the user did not significantly change this BDS's behavior with
8057 * some explicit (strong) options
8058 * - no non-file child of this BDS has been overridden by the user
8059 * Both of these conditions are represented by generate_json_filename.
8061 if (primary_child_bs
->exact_filename
[0] &&
8062 primary_child_bs
->drv
->bdrv_file_open
&&
8063 !drv
->is_filter
&& !generate_json_filename
)
8065 strcpy(bs
->exact_filename
, primary_child_bs
->exact_filename
);
8069 if (bs
->exact_filename
[0]) {
8070 pstrcpy(bs
->filename
, sizeof(bs
->filename
), bs
->exact_filename
);
8072 GString
*json
= qobject_to_json(QOBJECT(bs
->full_open_options
));
8073 if (snprintf(bs
->filename
, sizeof(bs
->filename
), "json:%s",
8074 json
->str
) >= sizeof(bs
->filename
)) {
8075 /* Give user a hint if we truncated things. */
8076 strcpy(bs
->filename
+ sizeof(bs
->filename
) - 4, "...");
8078 g_string_free(json
, true);
8082 char *bdrv_dirname(BlockDriverState
*bs
, Error
**errp
)
8084 BlockDriver
*drv
= bs
->drv
;
8085 BlockDriverState
*child_bs
;
8087 GLOBAL_STATE_CODE();
8090 error_setg(errp
, "Node '%s' is ejected", bs
->node_name
);
8094 if (drv
->bdrv_dirname
) {
8095 return drv
->bdrv_dirname(bs
, errp
);
8098 child_bs
= bdrv_primary_bs(bs
);
8100 return bdrv_dirname(child_bs
, errp
);
8103 bdrv_refresh_filename(bs
);
8104 if (bs
->exact_filename
[0] != '\0') {
8105 return path_combine(bs
->exact_filename
, "");
8108 error_setg(errp
, "Cannot generate a base directory for %s nodes",
8114 * Hot add/remove a BDS's child. So the user can take a child offline when
8115 * it is broken and take a new child online
8117 void bdrv_add_child(BlockDriverState
*parent_bs
, BlockDriverState
*child_bs
,
8120 GLOBAL_STATE_CODE();
8121 if (!parent_bs
->drv
|| !parent_bs
->drv
->bdrv_add_child
) {
8122 error_setg(errp
, "The node %s does not support adding a child",
8123 bdrv_get_device_or_node_name(parent_bs
));
8128 * Non-zoned block drivers do not follow zoned storage constraints
8129 * (i.e. sequential writes to zones). Refuse mixing zoned and non-zoned
8130 * drivers in a graph.
8132 if (!parent_bs
->drv
->supports_zoned_children
&&
8133 child_bs
->bl
.zoned
== BLK_Z_HM
) {
8135 * The host-aware model allows zoned storage constraints and random
8136 * write. Allow mixing host-aware and non-zoned drivers. Using
8137 * host-aware device as a regular device.
8139 error_setg(errp
, "Cannot add a %s child to a %s parent",
8140 child_bs
->bl
.zoned
== BLK_Z_HM
? "zoned" : "non-zoned",
8141 parent_bs
->drv
->supports_zoned_children
?
8142 "support zoned children" : "not support zoned children");
8146 if (!QLIST_EMPTY(&child_bs
->parents
)) {
8147 error_setg(errp
, "The node %s already has a parent",
8148 child_bs
->node_name
);
8152 parent_bs
->drv
->bdrv_add_child(parent_bs
, child_bs
, errp
);
8155 void bdrv_del_child(BlockDriverState
*parent_bs
, BdrvChild
*child
, Error
**errp
)
8159 GLOBAL_STATE_CODE();
8160 if (!parent_bs
->drv
|| !parent_bs
->drv
->bdrv_del_child
) {
8161 error_setg(errp
, "The node %s does not support removing a child",
8162 bdrv_get_device_or_node_name(parent_bs
));
8166 QLIST_FOREACH(tmp
, &parent_bs
->children
, next
) {
8173 error_setg(errp
, "The node %s does not have a child named %s",
8174 bdrv_get_device_or_node_name(parent_bs
),
8175 bdrv_get_device_or_node_name(child
->bs
));
8179 parent_bs
->drv
->bdrv_del_child(parent_bs
, child
, errp
);
8182 int bdrv_make_empty(BdrvChild
*c
, Error
**errp
)
8184 BlockDriver
*drv
= c
->bs
->drv
;
8187 GLOBAL_STATE_CODE();
8188 assert(c
->perm
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
));
8190 if (!drv
->bdrv_make_empty
) {
8191 error_setg(errp
, "%s does not support emptying nodes",
8196 ret
= drv
->bdrv_make_empty(c
->bs
);
8198 error_setg_errno(errp
, -ret
, "Failed to empty %s",
8207 * Return the child that @bs acts as an overlay for, and from which data may be
8208 * copied in COW or COR operations. Usually this is the backing file.
8210 BdrvChild
*bdrv_cow_child(BlockDriverState
*bs
)
8214 if (!bs
|| !bs
->drv
) {
8218 if (bs
->drv
->is_filter
) {
8226 assert(bs
->backing
->role
& BDRV_CHILD_COW
);
8231 * If @bs acts as a filter for exactly one of its children, return
8234 BdrvChild
*bdrv_filter_child(BlockDriverState
*bs
)
8239 if (!bs
|| !bs
->drv
) {
8243 if (!bs
->drv
->is_filter
) {
8247 /* Only one of @backing or @file may be used */
8248 assert(!(bs
->backing
&& bs
->file
));
8250 c
= bs
->backing
?: bs
->file
;
8255 assert(c
->role
& BDRV_CHILD_FILTERED
);
8260 * Return either the result of bdrv_cow_child() or bdrv_filter_child(),
8261 * whichever is non-NULL.
8263 * Return NULL if both are NULL.
8265 BdrvChild
*bdrv_filter_or_cow_child(BlockDriverState
*bs
)
8267 BdrvChild
*cow_child
= bdrv_cow_child(bs
);
8268 BdrvChild
*filter_child
= bdrv_filter_child(bs
);
8271 /* Filter nodes cannot have COW backing files */
8272 assert(!(cow_child
&& filter_child
));
8274 return cow_child
?: filter_child
;
8278 * Return the primary child of this node: For filters, that is the
8279 * filtered child. For other nodes, that is usually the child storing
8281 * (A generally more helpful description is that this is (usually) the
8282 * child that has the same filename as @bs.)
8284 * Drivers do not necessarily have a primary child; for example quorum
8287 BdrvChild
*bdrv_primary_child(BlockDriverState
*bs
)
8289 BdrvChild
*c
, *found
= NULL
;
8292 QLIST_FOREACH(c
, &bs
->children
, next
) {
8293 if (c
->role
& BDRV_CHILD_PRIMARY
) {
8302 static BlockDriverState
*bdrv_do_skip_filters(BlockDriverState
*bs
,
8303 bool stop_on_explicit_filter
)
8311 while (!(stop_on_explicit_filter
&& !bs
->implicit
)) {
8312 c
= bdrv_filter_child(bs
);
8315 * A filter that is embedded in a working block graph must
8316 * have a child. Assert this here so this function does
8317 * not return a filter node that is not expected by the
8320 assert(!bs
->drv
|| !bs
->drv
->is_filter
);
8326 * Note that this treats nodes with bs->drv == NULL as not being
8327 * filters (bs->drv == NULL should be replaced by something else
8329 * The advantage of this behavior is that this function will thus
8330 * always return a non-NULL value (given a non-NULL @bs).
8337 * Return the first BDS that has not been added implicitly or that
8338 * does not have a filtered child down the chain starting from @bs
8339 * (including @bs itself).
8341 BlockDriverState
*bdrv_skip_implicit_filters(BlockDriverState
*bs
)
8343 GLOBAL_STATE_CODE();
8344 return bdrv_do_skip_filters(bs
, true);
8348 * Return the first BDS that does not have a filtered child down the
8349 * chain starting from @bs (including @bs itself).
8351 BlockDriverState
*bdrv_skip_filters(BlockDriverState
*bs
)
8354 return bdrv_do_skip_filters(bs
, false);
8358 * For a backing chain, return the first non-filter backing image of
8359 * the first non-filter image.
8361 BlockDriverState
*bdrv_backing_chain_next(BlockDriverState
*bs
)
8364 return bdrv_skip_filters(bdrv_cow_bs(bdrv_skip_filters(bs
)));
8368 * Check whether [offset, offset + bytes) overlaps with the cached
8369 * block-status data region.
8371 * If so, and @pnum is not NULL, set *pnum to `bsc.data_end - offset`,
8372 * which is what bdrv_bsc_is_data()'s interface needs.
8373 * Otherwise, *pnum is not touched.
8375 static bool bdrv_bsc_range_overlaps_locked(BlockDriverState
*bs
,
8376 int64_t offset
, int64_t bytes
,
8379 BdrvBlockStatusCache
*bsc
= qatomic_rcu_read(&bs
->block_status_cache
);
8383 qatomic_read(&bsc
->valid
) &&
8384 ranges_overlap(offset
, bytes
, bsc
->data_start
,
8385 bsc
->data_end
- bsc
->data_start
);
8387 if (overlaps
&& pnum
) {
8388 *pnum
= bsc
->data_end
- offset
;
8395 * See block_int.h for this function's documentation.
8397 bool bdrv_bsc_is_data(BlockDriverState
*bs
, int64_t offset
, int64_t *pnum
)
8400 RCU_READ_LOCK_GUARD();
8401 return bdrv_bsc_range_overlaps_locked(bs
, offset
, 1, pnum
);
8405 * See block_int.h for this function's documentation.
8407 void bdrv_bsc_invalidate_range(BlockDriverState
*bs
,
8408 int64_t offset
, int64_t bytes
)
8411 RCU_READ_LOCK_GUARD();
8413 if (bdrv_bsc_range_overlaps_locked(bs
, offset
, bytes
, NULL
)) {
8414 qatomic_set(&bs
->block_status_cache
->valid
, false);
8419 * See block_int.h for this function's documentation.
8421 void bdrv_bsc_fill(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
)
8423 BdrvBlockStatusCache
*new_bsc
= g_new(BdrvBlockStatusCache
, 1);
8424 BdrvBlockStatusCache
*old_bsc
;
8427 *new_bsc
= (BdrvBlockStatusCache
) {
8429 .data_start
= offset
,
8430 .data_end
= offset
+ bytes
,
8433 QEMU_LOCK_GUARD(&bs
->bsc_modify_lock
);
8435 old_bsc
= qatomic_rcu_read(&bs
->block_status_cache
);
8436 qatomic_rcu_set(&bs
->block_status_cache
, new_bsc
);
8438 g_free_rcu(old_bsc
, rcu
);