2 * QEMU System Emulator block driver
4 * Copyright (c) 2003 Fabrice Bellard
5 * Copyright (c) 2020 Virtuozzo International GmbH.
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26 #include "qemu/osdep.h"
27 #include "block/trace.h"
28 #include "block/block_int.h"
29 #include "block/blockjob.h"
30 #include "block/dirty-bitmap.h"
31 #include "block/fuse.h"
32 #include "block/nbd.h"
33 #include "block/qdict.h"
34 #include "qemu/error-report.h"
35 #include "block/module_block.h"
36 #include "qemu/main-loop.h"
37 #include "qemu/module.h"
38 #include "qapi/error.h"
39 #include "qapi/qmp/qdict.h"
40 #include "qapi/qmp/qjson.h"
41 #include "qapi/qmp/qnull.h"
42 #include "qapi/qmp/qstring.h"
43 #include "qapi/qobject-output-visitor.h"
44 #include "qapi/qapi-visit-block-core.h"
45 #include "sysemu/block-backend.h"
46 #include "qemu/notify.h"
47 #include "qemu/option.h"
48 #include "qemu/coroutine.h"
49 #include "block/qapi.h"
50 #include "qemu/timer.h"
51 #include "qemu/cutils.h"
53 #include "qemu/range.h"
55 #include "block/coroutines.h"
58 #include <sys/ioctl.h>
59 #include <sys/queue.h>
60 #if defined(HAVE_SYS_DISK_H)
69 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
71 /* Protected by BQL */
72 static QTAILQ_HEAD(, BlockDriverState
) graph_bdrv_states
=
73 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states
);
75 /* Protected by BQL */
76 static QTAILQ_HEAD(, BlockDriverState
) all_bdrv_states
=
77 QTAILQ_HEAD_INITIALIZER(all_bdrv_states
);
79 /* Protected by BQL */
80 static QLIST_HEAD(, BlockDriver
) bdrv_drivers
=
81 QLIST_HEAD_INITIALIZER(bdrv_drivers
);
83 static BlockDriverState
*bdrv_open_inherit(const char *filename
,
84 const char *reference
,
85 QDict
*options
, int flags
,
86 BlockDriverState
*parent
,
87 const BdrvChildClass
*child_class
,
88 BdrvChildRole child_role
,
91 static bool bdrv_recurse_has_child(BlockDriverState
*bs
,
92 BlockDriverState
*child
);
94 static void bdrv_replace_child_noperm(BdrvChild
*child
,
95 BlockDriverState
*new_bs
);
96 static void bdrv_remove_child(BdrvChild
*child
, Transaction
*tran
);
98 static int bdrv_reopen_prepare(BDRVReopenState
*reopen_state
,
99 BlockReopenQueue
*queue
,
100 Transaction
*change_child_tran
, Error
**errp
);
101 static void bdrv_reopen_commit(BDRVReopenState
*reopen_state
);
102 static void bdrv_reopen_abort(BDRVReopenState
*reopen_state
);
104 static bool bdrv_backing_overridden(BlockDriverState
*bs
);
106 static bool bdrv_change_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
107 GHashTable
*visited
, Transaction
*tran
,
110 /* If non-zero, use only whitelisted block drivers */
111 static int use_bdrv_whitelist
;
114 static int is_windows_drive_prefix(const char *filename
)
116 return (((filename
[0] >= 'a' && filename
[0] <= 'z') ||
117 (filename
[0] >= 'A' && filename
[0] <= 'Z')) &&
121 int is_windows_drive(const char *filename
)
123 if (is_windows_drive_prefix(filename
) &&
126 if (strstart(filename
, "\\\\.\\", NULL
) ||
127 strstart(filename
, "//./", NULL
))
133 size_t bdrv_opt_mem_align(BlockDriverState
*bs
)
135 if (!bs
|| !bs
->drv
) {
136 /* page size or 4k (hdd sector size) should be on the safe side */
137 return MAX(4096, qemu_real_host_page_size());
141 return bs
->bl
.opt_mem_alignment
;
144 size_t bdrv_min_mem_align(BlockDriverState
*bs
)
146 if (!bs
|| !bs
->drv
) {
147 /* page size or 4k (hdd sector size) should be on the safe side */
148 return MAX(4096, qemu_real_host_page_size());
152 return bs
->bl
.min_mem_alignment
;
155 /* check if the path starts with "<protocol>:" */
156 int path_has_protocol(const char *path
)
161 if (is_windows_drive(path
) ||
162 is_windows_drive_prefix(path
)) {
165 p
= path
+ strcspn(path
, ":/\\");
167 p
= path
+ strcspn(path
, ":/");
173 int path_is_absolute(const char *path
)
176 /* specific case for names like: "\\.\d:" */
177 if (is_windows_drive(path
) || is_windows_drive_prefix(path
)) {
180 return (*path
== '/' || *path
== '\\');
182 return (*path
== '/');
186 /* if filename is absolute, just return its duplicate. Otherwise, build a
187 path to it by considering it is relative to base_path. URL are
189 char *path_combine(const char *base_path
, const char *filename
)
191 const char *protocol_stripped
= NULL
;
196 if (path_is_absolute(filename
)) {
197 return g_strdup(filename
);
200 if (path_has_protocol(base_path
)) {
201 protocol_stripped
= strchr(base_path
, ':');
202 if (protocol_stripped
) {
206 p
= protocol_stripped
?: base_path
;
208 p1
= strrchr(base_path
, '/');
212 p2
= strrchr(base_path
, '\\');
213 if (!p1
|| p2
> p1
) {
228 result
= g_malloc(len
+ strlen(filename
) + 1);
229 memcpy(result
, base_path
, len
);
230 strcpy(result
+ len
, filename
);
236 * Helper function for bdrv_parse_filename() implementations to remove optional
237 * protocol prefixes (especially "file:") from a filename and for putting the
238 * stripped filename into the options QDict if there is such a prefix.
240 void bdrv_parse_filename_strip_prefix(const char *filename
, const char *prefix
,
243 if (strstart(filename
, prefix
, &filename
)) {
244 /* Stripping the explicit protocol prefix may result in a protocol
245 * prefix being (wrongly) detected (if the filename contains a colon) */
246 if (path_has_protocol(filename
)) {
247 GString
*fat_filename
;
249 /* This means there is some colon before the first slash; therefore,
250 * this cannot be an absolute path */
251 assert(!path_is_absolute(filename
));
253 /* And we can thus fix the protocol detection issue by prefixing it
255 fat_filename
= g_string_new("./");
256 g_string_append(fat_filename
, filename
);
258 assert(!path_has_protocol(fat_filename
->str
));
260 qdict_put(options
, "filename",
261 qstring_from_gstring(fat_filename
));
263 /* If no protocol prefix was detected, we can use the shortened
265 qdict_put_str(options
, "filename", filename
);
271 /* Returns whether the image file is opened as read-only. Note that this can
272 * return false and writing to the image file is still not possible because the
273 * image is inactivated. */
274 bool bdrv_is_read_only(BlockDriverState
*bs
)
277 return !(bs
->open_flags
& BDRV_O_RDWR
);
280 static int bdrv_can_set_read_only(BlockDriverState
*bs
, bool read_only
,
281 bool ignore_allow_rdw
, Error
**errp
)
285 /* Do not set read_only if copy_on_read is enabled */
286 if (bs
->copy_on_read
&& read_only
) {
287 error_setg(errp
, "Can't set node '%s' to r/o with copy-on-read enabled",
288 bdrv_get_device_or_node_name(bs
));
292 /* Do not clear read_only if it is prohibited */
293 if (!read_only
&& !(bs
->open_flags
& BDRV_O_ALLOW_RDWR
) &&
296 error_setg(errp
, "Node '%s' is read only",
297 bdrv_get_device_or_node_name(bs
));
305 * Called by a driver that can only provide a read-only image.
307 * Returns 0 if the node is already read-only or it could switch the node to
308 * read-only because BDRV_O_AUTO_RDONLY is set.
310 * Returns -EACCES if the node is read-write and BDRV_O_AUTO_RDONLY is not set
311 * or bdrv_can_set_read_only() forbids making the node read-only. If @errmsg
312 * is not NULL, it is used as the error message for the Error object.
314 int bdrv_apply_auto_read_only(BlockDriverState
*bs
, const char *errmsg
,
320 if (!(bs
->open_flags
& BDRV_O_RDWR
)) {
323 if (!(bs
->open_flags
& BDRV_O_AUTO_RDONLY
)) {
327 ret
= bdrv_can_set_read_only(bs
, true, false, NULL
);
332 bs
->open_flags
&= ~BDRV_O_RDWR
;
337 error_setg(errp
, "%s", errmsg
?: "Image is read-only");
342 * If @backing is empty, this function returns NULL without setting
343 * @errp. In all other cases, NULL will only be returned with @errp
346 * Therefore, a return value of NULL without @errp set means that
347 * there is no backing file; if @errp is set, there is one but its
348 * absolute filename cannot be generated.
350 char *bdrv_get_full_backing_filename_from_filename(const char *backed
,
354 if (backing
[0] == '\0') {
356 } else if (path_has_protocol(backing
) || path_is_absolute(backing
)) {
357 return g_strdup(backing
);
358 } else if (backed
[0] == '\0' || strstart(backed
, "json:", NULL
)) {
359 error_setg(errp
, "Cannot use relative backing file names for '%s'",
363 return path_combine(backed
, backing
);
368 * If @filename is empty or NULL, this function returns NULL without
369 * setting @errp. In all other cases, NULL will only be returned with
372 static char *bdrv_make_absolute_filename(BlockDriverState
*relative_to
,
373 const char *filename
, Error
**errp
)
375 char *dir
, *full_name
;
377 if (!filename
|| filename
[0] == '\0') {
379 } else if (path_has_protocol(filename
) || path_is_absolute(filename
)) {
380 return g_strdup(filename
);
383 dir
= bdrv_dirname(relative_to
, errp
);
388 full_name
= g_strconcat(dir
, filename
, NULL
);
393 char *bdrv_get_full_backing_filename(BlockDriverState
*bs
, Error
**errp
)
396 return bdrv_make_absolute_filename(bs
, bs
->backing_file
, errp
);
399 void bdrv_register(BlockDriver
*bdrv
)
401 assert(bdrv
->format_name
);
403 QLIST_INSERT_HEAD(&bdrv_drivers
, bdrv
, list
);
406 BlockDriverState
*bdrv_new(void)
408 BlockDriverState
*bs
;
413 bs
= g_new0(BlockDriverState
, 1);
414 QLIST_INIT(&bs
->dirty_bitmaps
);
415 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
416 QLIST_INIT(&bs
->op_blockers
[i
]);
418 qemu_mutex_init(&bs
->reqs_lock
);
419 qemu_mutex_init(&bs
->dirty_bitmap_mutex
);
421 bs
->aio_context
= qemu_get_aio_context();
423 qemu_co_queue_init(&bs
->flush_queue
);
425 qemu_co_mutex_init(&bs
->bsc_modify_lock
);
426 bs
->block_status_cache
= g_new0(BdrvBlockStatusCache
, 1);
428 for (i
= 0; i
< bdrv_drain_all_count
; i
++) {
429 bdrv_drained_begin(bs
);
432 QTAILQ_INSERT_TAIL(&all_bdrv_states
, bs
, bs_list
);
437 static BlockDriver
*bdrv_do_find_format(const char *format_name
)
442 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
443 if (!strcmp(drv1
->format_name
, format_name
)) {
451 BlockDriver
*bdrv_find_format(const char *format_name
)
458 drv1
= bdrv_do_find_format(format_name
);
463 /* The driver isn't registered, maybe we need to load a module */
464 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
465 if (!strcmp(block_driver_modules
[i
].format_name
, format_name
)) {
466 Error
*local_err
= NULL
;
467 int rv
= block_module_load(block_driver_modules
[i
].library_name
,
470 return bdrv_do_find_format(format_name
);
472 error_report_err(local_err
);
480 static int bdrv_format_is_whitelisted(const char *format_name
, bool read_only
)
482 static const char *whitelist_rw
[] = {
483 CONFIG_BDRV_RW_WHITELIST
486 static const char *whitelist_ro
[] = {
487 CONFIG_BDRV_RO_WHITELIST
492 if (!whitelist_rw
[0] && !whitelist_ro
[0]) {
493 return 1; /* no whitelist, anything goes */
496 for (p
= whitelist_rw
; *p
; p
++) {
497 if (!strcmp(format_name
, *p
)) {
502 for (p
= whitelist_ro
; *p
; p
++) {
503 if (!strcmp(format_name
, *p
)) {
511 int bdrv_is_whitelisted(BlockDriver
*drv
, bool read_only
)
514 return bdrv_format_is_whitelisted(drv
->format_name
, read_only
);
517 bool bdrv_uses_whitelist(void)
519 return use_bdrv_whitelist
;
522 typedef struct CreateCo
{
530 int coroutine_fn
bdrv_co_create(BlockDriver
*drv
, const char *filename
,
531 QemuOpts
*opts
, Error
**errp
)
537 if (!drv
->bdrv_co_create_opts
) {
538 error_setg(errp
, "Driver '%s' does not support image creation",
543 ret
= drv
->bdrv_co_create_opts(drv
, filename
, opts
, errp
);
544 if (ret
< 0 && !*errp
) {
545 error_setg_errno(errp
, -ret
, "Could not create image");
552 * Helper function for bdrv_create_file_fallback(): Resize @blk to at
553 * least the given @minimum_size.
555 * On success, return @blk's actual length.
556 * Otherwise, return -errno.
558 static int64_t coroutine_fn GRAPH_UNLOCKED
559 create_file_fallback_truncate(BlockBackend
*blk
, int64_t minimum_size
,
562 Error
*local_err
= NULL
;
568 ret
= blk_co_truncate(blk
, minimum_size
, false, PREALLOC_MODE_OFF
, 0,
570 if (ret
< 0 && ret
!= -ENOTSUP
) {
571 error_propagate(errp
, local_err
);
575 size
= blk_co_getlength(blk
);
577 error_free(local_err
);
578 error_setg_errno(errp
, -size
,
579 "Failed to inquire the new image file's length");
583 if (size
< minimum_size
) {
584 /* Need to grow the image, but we failed to do that */
585 error_propagate(errp
, local_err
);
589 error_free(local_err
);
596 * Helper function for bdrv_create_file_fallback(): Zero the first
597 * sector to remove any potentially pre-existing image header.
599 static int coroutine_fn
600 create_file_fallback_zero_first_sector(BlockBackend
*blk
,
601 int64_t current_size
,
604 int64_t bytes_to_clear
;
609 bytes_to_clear
= MIN(current_size
, BDRV_SECTOR_SIZE
);
610 if (bytes_to_clear
) {
611 ret
= blk_co_pwrite_zeroes(blk
, 0, bytes_to_clear
, BDRV_REQ_MAY_UNMAP
);
613 error_setg_errno(errp
, -ret
,
614 "Failed to clear the new image's first sector");
623 * Simple implementation of bdrv_co_create_opts for protocol drivers
624 * which only support creation via opening a file
625 * (usually existing raw storage device)
627 int coroutine_fn
bdrv_co_create_opts_simple(BlockDriver
*drv
,
628 const char *filename
,
636 PreallocMode prealloc
;
637 Error
*local_err
= NULL
;
642 size
= qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0);
643 buf
= qemu_opt_get_del(opts
, BLOCK_OPT_PREALLOC
);
644 prealloc
= qapi_enum_parse(&PreallocMode_lookup
, buf
,
645 PREALLOC_MODE_OFF
, &local_err
);
648 error_propagate(errp
, local_err
);
652 if (prealloc
!= PREALLOC_MODE_OFF
) {
653 error_setg(errp
, "Unsupported preallocation mode '%s'",
654 PreallocMode_str(prealloc
));
658 options
= qdict_new();
659 qdict_put_str(options
, "driver", drv
->format_name
);
661 blk
= blk_co_new_open(filename
, NULL
, options
,
662 BDRV_O_RDWR
| BDRV_O_RESIZE
, errp
);
664 error_prepend(errp
, "Protocol driver '%s' does not support creating "
665 "new images, so an existing image must be selected as "
666 "the target; however, opening the given target as an "
667 "existing image failed: ",
672 size
= create_file_fallback_truncate(blk
, size
, errp
);
678 ret
= create_file_fallback_zero_first_sector(blk
, size
, errp
);
689 int coroutine_fn
bdrv_co_create_file(const char *filename
, QemuOpts
*opts
,
692 QemuOpts
*protocol_opts
;
699 drv
= bdrv_find_protocol(filename
, true, errp
);
704 if (!drv
->create_opts
) {
705 error_setg(errp
, "Driver '%s' does not support image creation",
711 * 'opts' contains a QemuOptsList with a combination of format and protocol
714 * The format properly removes its options, but the default values remain
715 * in 'opts->list'. So if the protocol has options with the same name
716 * (e.g. rbd has 'cluster_size' as qcow2), it will see the default values
717 * of the format, since for overlapping options, the format wins.
719 * To avoid this issue, lets convert QemuOpts to QDict, in this way we take
720 * only the set options, and then convert it back to QemuOpts, using the
721 * create_opts of the protocol. So the new QemuOpts, will contain only the
724 qdict
= qemu_opts_to_qdict(opts
, NULL
);
725 protocol_opts
= qemu_opts_from_qdict(drv
->create_opts
, qdict
, errp
);
726 if (protocol_opts
== NULL
) {
731 ret
= bdrv_co_create(drv
, filename
, protocol_opts
, errp
);
733 qemu_opts_del(protocol_opts
);
734 qobject_unref(qdict
);
738 int coroutine_fn
bdrv_co_delete_file(BlockDriverState
*bs
, Error
**errp
)
740 Error
*local_err
= NULL
;
745 assert_bdrv_graph_readable();
748 error_setg(errp
, "Block node '%s' is not opened", bs
->filename
);
752 if (!bs
->drv
->bdrv_co_delete_file
) {
753 error_setg(errp
, "Driver '%s' does not support image deletion",
754 bs
->drv
->format_name
);
758 ret
= bs
->drv
->bdrv_co_delete_file(bs
, &local_err
);
760 error_propagate(errp
, local_err
);
766 void coroutine_fn
bdrv_co_delete_file_noerr(BlockDriverState
*bs
)
768 Error
*local_err
= NULL
;
776 ret
= bdrv_co_delete_file(bs
, &local_err
);
778 * ENOTSUP will happen if the block driver doesn't support
779 * the 'bdrv_co_delete_file' interface. This is a predictable
780 * scenario and shouldn't be reported back to the user.
782 if (ret
== -ENOTSUP
) {
783 error_free(local_err
);
784 } else if (ret
< 0) {
785 error_report_err(local_err
);
790 * Try to get @bs's logical and physical block size.
791 * On success, store them in @bsz struct and return 0.
792 * On failure return -errno.
793 * @bs must not be empty.
795 int bdrv_probe_blocksizes(BlockDriverState
*bs
, BlockSizes
*bsz
)
797 BlockDriver
*drv
= bs
->drv
;
798 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
801 if (drv
&& drv
->bdrv_probe_blocksizes
) {
802 return drv
->bdrv_probe_blocksizes(bs
, bsz
);
803 } else if (filtered
) {
804 return bdrv_probe_blocksizes(filtered
, bsz
);
811 * Try to get @bs's geometry (cyls, heads, sectors).
812 * On success, store them in @geo struct and return 0.
813 * On failure return -errno.
814 * @bs must not be empty.
816 int bdrv_probe_geometry(BlockDriverState
*bs
, HDGeometry
*geo
)
818 BlockDriver
*drv
= bs
->drv
;
819 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
822 if (drv
&& drv
->bdrv_probe_geometry
) {
823 return drv
->bdrv_probe_geometry(bs
, geo
);
824 } else if (filtered
) {
825 return bdrv_probe_geometry(filtered
, geo
);
832 * Create a uniquely-named empty temporary file.
833 * Return the actual file name used upon success, otherwise NULL.
834 * This string should be freed with g_free() when not needed any longer.
836 * Note: creating a temporary file for the caller to (re)open is
837 * inherently racy. Use g_file_open_tmp() instead whenever practical.
839 char *create_tmp_file(Error
**errp
)
843 g_autofree
char *filename
= NULL
;
845 tmpdir
= g_get_tmp_dir();
848 * See commit 69bef79 ("block: use /var/tmp instead of /tmp for -snapshot")
850 * This function is used to create temporary disk images (like -snapshot),
851 * so the files can become very large. /tmp is often a tmpfs where as
852 * /var/tmp is usually on a disk, so more appropriate for disk images.
854 if (!g_strcmp0(tmpdir
, "/tmp")) {
859 filename
= g_strdup_printf("%s/vl.XXXXXX", tmpdir
);
860 fd
= g_mkstemp(filename
);
862 error_setg_errno(errp
, errno
, "Could not open temporary file '%s'",
868 return g_steal_pointer(&filename
);
872 * Detect host devices. By convention, /dev/cdrom[N] is always
873 * recognized as a host CDROM.
875 static BlockDriver
*find_hdev_driver(const char *filename
)
877 int score_max
= 0, score
;
878 BlockDriver
*drv
= NULL
, *d
;
881 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
882 if (d
->bdrv_probe_device
) {
883 score
= d
->bdrv_probe_device(filename
);
884 if (score
> score_max
) {
894 static BlockDriver
*bdrv_do_find_protocol(const char *protocol
)
899 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
900 if (drv1
->protocol_name
&& !strcmp(drv1
->protocol_name
, protocol
)) {
908 BlockDriver
*bdrv_find_protocol(const char *filename
,
909 bool allow_protocol_prefix
,
919 /* TODO Drivers without bdrv_file_open must be specified explicitly */
922 * XXX(hch): we really should not let host device detection
923 * override an explicit protocol specification, but moving this
924 * later breaks access to device names with colons in them.
925 * Thanks to the brain-dead persistent naming schemes on udev-
926 * based Linux systems those actually are quite common.
928 drv1
= find_hdev_driver(filename
);
933 if (!path_has_protocol(filename
) || !allow_protocol_prefix
) {
937 p
= strchr(filename
, ':');
940 if (len
> sizeof(protocol
) - 1)
941 len
= sizeof(protocol
) - 1;
942 memcpy(protocol
, filename
, len
);
943 protocol
[len
] = '\0';
945 drv1
= bdrv_do_find_protocol(protocol
);
950 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
951 if (block_driver_modules
[i
].protocol_name
&&
952 !strcmp(block_driver_modules
[i
].protocol_name
, protocol
)) {
953 int rv
= block_module_load(block_driver_modules
[i
].library_name
, errp
);
955 drv1
= bdrv_do_find_protocol(protocol
);
964 error_setg(errp
, "Unknown protocol '%s'", protocol
);
970 * Guess image format by probing its contents.
971 * This is not a good idea when your image is raw (CVE-2008-2004), but
972 * we do it anyway for backward compatibility.
974 * @buf contains the image's first @buf_size bytes.
975 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
976 * but can be smaller if the image file is smaller)
977 * @filename is its filename.
979 * For all block drivers, call the bdrv_probe() method to get its
981 * Return the first block driver with the highest probing score.
983 BlockDriver
*bdrv_probe_all(const uint8_t *buf
, int buf_size
,
984 const char *filename
)
986 int score_max
= 0, score
;
987 BlockDriver
*drv
= NULL
, *d
;
990 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
992 score
= d
->bdrv_probe(buf
, buf_size
, filename
);
993 if (score
> score_max
) {
1003 static int find_image_format(BlockBackend
*file
, const char *filename
,
1004 BlockDriver
**pdrv
, Error
**errp
)
1007 uint8_t buf
[BLOCK_PROBE_BUF_SIZE
];
1010 GLOBAL_STATE_CODE();
1012 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
1013 if (blk_is_sg(file
) || !blk_is_inserted(file
) || blk_getlength(file
) == 0) {
1018 ret
= blk_pread(file
, 0, sizeof(buf
), buf
, 0);
1020 error_setg_errno(errp
, -ret
, "Could not read image for determining its "
1026 drv
= bdrv_probe_all(buf
, sizeof(buf
), filename
);
1028 error_setg(errp
, "Could not determine image format: No compatible "
1039 * Set the current 'total_sectors' value
1040 * Return 0 on success, -errno on error.
1042 int coroutine_fn
bdrv_co_refresh_total_sectors(BlockDriverState
*bs
,
1045 BlockDriver
*drv
= bs
->drv
;
1047 assert_bdrv_graph_readable();
1053 /* Do not attempt drv->bdrv_co_getlength() on scsi-generic devices */
1057 /* query actual device if possible, otherwise just trust the hint */
1058 if (drv
->bdrv_co_getlength
) {
1059 int64_t length
= drv
->bdrv_co_getlength(bs
);
1063 hint
= DIV_ROUND_UP(length
, BDRV_SECTOR_SIZE
);
1066 bs
->total_sectors
= hint
;
1068 if (bs
->total_sectors
* BDRV_SECTOR_SIZE
> BDRV_MAX_LENGTH
) {
1076 * Combines a QDict of new block driver @options with any missing options taken
1077 * from @old_options, so that leaving out an option defaults to its old value.
1079 static void bdrv_join_options(BlockDriverState
*bs
, QDict
*options
,
1082 GLOBAL_STATE_CODE();
1083 if (bs
->drv
&& bs
->drv
->bdrv_join_options
) {
1084 bs
->drv
->bdrv_join_options(options
, old_options
);
1086 qdict_join(options
, old_options
, false);
1090 static BlockdevDetectZeroesOptions
bdrv_parse_detect_zeroes(QemuOpts
*opts
,
1094 Error
*local_err
= NULL
;
1095 char *value
= qemu_opt_get_del(opts
, "detect-zeroes");
1096 BlockdevDetectZeroesOptions detect_zeroes
=
1097 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup
, value
,
1098 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF
, &local_err
);
1099 GLOBAL_STATE_CODE();
1102 error_propagate(errp
, local_err
);
1103 return detect_zeroes
;
1106 if (detect_zeroes
== BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP
&&
1107 !(open_flags
& BDRV_O_UNMAP
))
1109 error_setg(errp
, "setting detect-zeroes to unmap is not allowed "
1110 "without setting discard operation to unmap");
1113 return detect_zeroes
;
1117 * Set open flags for aio engine
1119 * Return 0 on success, -1 if the engine specified is invalid
1121 int bdrv_parse_aio(const char *mode
, int *flags
)
1123 if (!strcmp(mode
, "threads")) {
1124 /* do nothing, default */
1125 } else if (!strcmp(mode
, "native")) {
1126 *flags
|= BDRV_O_NATIVE_AIO
;
1127 #ifdef CONFIG_LINUX_IO_URING
1128 } else if (!strcmp(mode
, "io_uring")) {
1129 *flags
|= BDRV_O_IO_URING
;
1139 * Set open flags for a given discard mode
1141 * Return 0 on success, -1 if the discard mode was invalid.
1143 int bdrv_parse_discard_flags(const char *mode
, int *flags
)
1145 *flags
&= ~BDRV_O_UNMAP
;
1147 if (!strcmp(mode
, "off") || !strcmp(mode
, "ignore")) {
1149 } else if (!strcmp(mode
, "on") || !strcmp(mode
, "unmap")) {
1150 *flags
|= BDRV_O_UNMAP
;
1159 * Set open flags for a given cache mode
1161 * Return 0 on success, -1 if the cache mode was invalid.
1163 int bdrv_parse_cache_mode(const char *mode
, int *flags
, bool *writethrough
)
1165 *flags
&= ~BDRV_O_CACHE_MASK
;
1167 if (!strcmp(mode
, "off") || !strcmp(mode
, "none")) {
1168 *writethrough
= false;
1169 *flags
|= BDRV_O_NOCACHE
;
1170 } else if (!strcmp(mode
, "directsync")) {
1171 *writethrough
= true;
1172 *flags
|= BDRV_O_NOCACHE
;
1173 } else if (!strcmp(mode
, "writeback")) {
1174 *writethrough
= false;
1175 } else if (!strcmp(mode
, "unsafe")) {
1176 *writethrough
= false;
1177 *flags
|= BDRV_O_NO_FLUSH
;
1178 } else if (!strcmp(mode
, "writethrough")) {
1179 *writethrough
= true;
1187 static char *bdrv_child_get_parent_desc(BdrvChild
*c
)
1189 BlockDriverState
*parent
= c
->opaque
;
1190 return g_strdup_printf("node '%s'", bdrv_get_node_name(parent
));
1193 static void bdrv_child_cb_drained_begin(BdrvChild
*child
)
1195 BlockDriverState
*bs
= child
->opaque
;
1196 bdrv_do_drained_begin_quiesce(bs
, NULL
);
1199 static bool bdrv_child_cb_drained_poll(BdrvChild
*child
)
1201 BlockDriverState
*bs
= child
->opaque
;
1202 return bdrv_drain_poll(bs
, NULL
, false);
1205 static void bdrv_child_cb_drained_end(BdrvChild
*child
)
1207 BlockDriverState
*bs
= child
->opaque
;
1208 bdrv_drained_end(bs
);
1211 static int bdrv_child_cb_inactivate(BdrvChild
*child
)
1213 BlockDriverState
*bs
= child
->opaque
;
1214 GLOBAL_STATE_CODE();
1215 assert(bs
->open_flags
& BDRV_O_INACTIVE
);
1219 static bool bdrv_child_cb_change_aio_ctx(BdrvChild
*child
, AioContext
*ctx
,
1220 GHashTable
*visited
, Transaction
*tran
,
1223 BlockDriverState
*bs
= child
->opaque
;
1224 return bdrv_change_aio_context(bs
, ctx
, visited
, tran
, errp
);
1228 * Returns the options and flags that a temporary snapshot should get, based on
1229 * the originally requested flags (the originally requested image will have
1230 * flags like a backing file)
1232 static void bdrv_temp_snapshot_options(int *child_flags
, QDict
*child_options
,
1233 int parent_flags
, QDict
*parent_options
)
1235 GLOBAL_STATE_CODE();
1236 *child_flags
= (parent_flags
& ~BDRV_O_SNAPSHOT
) | BDRV_O_TEMPORARY
;
1238 /* For temporary files, unconditional cache=unsafe is fine */
1239 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_DIRECT
, "off");
1240 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_NO_FLUSH
, "on");
1242 /* Copy the read-only and discard options from the parent */
1243 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1244 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_DISCARD
);
1246 /* aio=native doesn't work for cache.direct=off, so disable it for the
1247 * temporary snapshot */
1248 *child_flags
&= ~BDRV_O_NATIVE_AIO
;
1251 static void bdrv_backing_attach(BdrvChild
*c
)
1253 BlockDriverState
*parent
= c
->opaque
;
1254 BlockDriverState
*backing_hd
= c
->bs
;
1256 GLOBAL_STATE_CODE();
1257 assert(!parent
->backing_blocker
);
1258 error_setg(&parent
->backing_blocker
,
1259 "node is used as backing hd of '%s'",
1260 bdrv_get_device_or_node_name(parent
));
1262 bdrv_refresh_filename(backing_hd
);
1264 parent
->open_flags
&= ~BDRV_O_NO_BACKING
;
1266 bdrv_op_block_all(backing_hd
, parent
->backing_blocker
);
1267 /* Otherwise we won't be able to commit or stream */
1268 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_COMMIT_TARGET
,
1269 parent
->backing_blocker
);
1270 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_STREAM
,
1271 parent
->backing_blocker
);
1273 * We do backup in 3 ways:
1275 * The target bs is new opened, and the source is top BDS
1276 * 2. blockdev backup
1277 * Both the source and the target are top BDSes.
1278 * 3. internal backup(used for block replication)
1279 * Both the source and the target are backing file
1281 * In case 1 and 2, neither the source nor the target is the backing file.
1282 * In case 3, we will block the top BDS, so there is only one block job
1283 * for the top BDS and its backing chain.
1285 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_SOURCE
,
1286 parent
->backing_blocker
);
1287 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_TARGET
,
1288 parent
->backing_blocker
);
1291 static void bdrv_backing_detach(BdrvChild
*c
)
1293 BlockDriverState
*parent
= c
->opaque
;
1295 GLOBAL_STATE_CODE();
1296 assert(parent
->backing_blocker
);
1297 bdrv_op_unblock_all(c
->bs
, parent
->backing_blocker
);
1298 error_free(parent
->backing_blocker
);
1299 parent
->backing_blocker
= NULL
;
1302 static int bdrv_backing_update_filename(BdrvChild
*c
, BlockDriverState
*base
,
1303 const char *filename
, Error
**errp
)
1305 BlockDriverState
*parent
= c
->opaque
;
1306 bool read_only
= bdrv_is_read_only(parent
);
1308 GLOBAL_STATE_CODE();
1311 ret
= bdrv_reopen_set_read_only(parent
, false, errp
);
1317 ret
= bdrv_change_backing_file(parent
, filename
,
1318 base
->drv
? base
->drv
->format_name
: "",
1321 error_setg_errno(errp
, -ret
, "Could not update backing file link");
1325 bdrv_reopen_set_read_only(parent
, true, NULL
);
1332 * Returns the options and flags that a generic child of a BDS should
1333 * get, based on the given options and flags for the parent BDS.
1335 static void bdrv_inherited_options(BdrvChildRole role
, bool parent_is_format
,
1336 int *child_flags
, QDict
*child_options
,
1337 int parent_flags
, QDict
*parent_options
)
1339 int flags
= parent_flags
;
1340 GLOBAL_STATE_CODE();
1343 * First, decide whether to set, clear, or leave BDRV_O_PROTOCOL.
1344 * Generally, the question to answer is: Should this child be
1345 * format-probed by default?
1349 * Pure and non-filtered data children of non-format nodes should
1350 * be probed by default (even when the node itself has BDRV_O_PROTOCOL
1351 * set). This only affects a very limited set of drivers (namely
1352 * quorum and blkverify when this comment was written).
1353 * Force-clear BDRV_O_PROTOCOL then.
1355 if (!parent_is_format
&&
1356 (role
& BDRV_CHILD_DATA
) &&
1357 !(role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_FILTERED
)))
1359 flags
&= ~BDRV_O_PROTOCOL
;
1363 * All children of format nodes (except for COW children) and all
1364 * metadata children in general should never be format-probed.
1365 * Force-set BDRV_O_PROTOCOL then.
1367 if ((parent_is_format
&& !(role
& BDRV_CHILD_COW
)) ||
1368 (role
& BDRV_CHILD_METADATA
))
1370 flags
|= BDRV_O_PROTOCOL
;
1374 * If the cache mode isn't explicitly set, inherit direct and no-flush from
1377 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_DIRECT
);
1378 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_NO_FLUSH
);
1379 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_FORCE_SHARE
);
1381 if (role
& BDRV_CHILD_COW
) {
1382 /* backing files are opened read-only by default */
1383 qdict_set_default_str(child_options
, BDRV_OPT_READ_ONLY
, "on");
1384 qdict_set_default_str(child_options
, BDRV_OPT_AUTO_READ_ONLY
, "off");
1386 /* Inherit the read-only option from the parent if it's not set */
1387 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
1388 qdict_copy_default(child_options
, parent_options
,
1389 BDRV_OPT_AUTO_READ_ONLY
);
1393 * bdrv_co_pdiscard() respects unmap policy for the parent, so we
1394 * can default to enable it on lower layers regardless of the
1397 qdict_set_default_str(child_options
, BDRV_OPT_DISCARD
, "unmap");
1399 /* Clear flags that only apply to the top layer */
1400 flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_COPY_ON_READ
);
1402 if (role
& BDRV_CHILD_METADATA
) {
1403 flags
&= ~BDRV_O_NO_IO
;
1405 if (role
& BDRV_CHILD_COW
) {
1406 flags
&= ~BDRV_O_TEMPORARY
;
1409 *child_flags
= flags
;
1412 static void GRAPH_WRLOCK
bdrv_child_cb_attach(BdrvChild
*child
)
1414 BlockDriverState
*bs
= child
->opaque
;
1416 assert_bdrv_graph_writable();
1417 QLIST_INSERT_HEAD(&bs
->children
, child
, next
);
1418 if (bs
->drv
->is_filter
|| (child
->role
& BDRV_CHILD_FILTERED
)) {
1420 * Here we handle filters and block/raw-format.c when it behave like
1421 * filter. They generally have a single PRIMARY child, which is also the
1422 * FILTERED child, and that they may have multiple more children, which
1423 * are neither PRIMARY nor FILTERED. And never we have a COW child here.
1424 * So bs->file will be the PRIMARY child, unless the PRIMARY child goes
1425 * into bs->backing on exceptional cases; and bs->backing will be
1428 assert(!(child
->role
& BDRV_CHILD_COW
));
1429 if (child
->role
& BDRV_CHILD_PRIMARY
) {
1430 assert(child
->role
& BDRV_CHILD_FILTERED
);
1431 assert(!bs
->backing
);
1434 if (bs
->drv
->filtered_child_is_backing
) {
1435 bs
->backing
= child
;
1440 assert(!(child
->role
& BDRV_CHILD_FILTERED
));
1442 } else if (child
->role
& BDRV_CHILD_COW
) {
1443 assert(bs
->drv
->supports_backing
);
1444 assert(!(child
->role
& BDRV_CHILD_PRIMARY
));
1445 assert(!bs
->backing
);
1446 bs
->backing
= child
;
1447 bdrv_backing_attach(child
);
1448 } else if (child
->role
& BDRV_CHILD_PRIMARY
) {
1454 static void GRAPH_WRLOCK
bdrv_child_cb_detach(BdrvChild
*child
)
1456 BlockDriverState
*bs
= child
->opaque
;
1458 if (child
->role
& BDRV_CHILD_COW
) {
1459 bdrv_backing_detach(child
);
1462 assert_bdrv_graph_writable();
1463 QLIST_REMOVE(child
, next
);
1464 if (child
== bs
->backing
) {
1465 assert(child
!= bs
->file
);
1467 } else if (child
== bs
->file
) {
1472 static int bdrv_child_cb_update_filename(BdrvChild
*c
, BlockDriverState
*base
,
1473 const char *filename
, Error
**errp
)
1475 if (c
->role
& BDRV_CHILD_COW
) {
1476 return bdrv_backing_update_filename(c
, base
, filename
, errp
);
1481 AioContext
*child_of_bds_get_parent_aio_context(BdrvChild
*c
)
1483 BlockDriverState
*bs
= c
->opaque
;
1486 return bdrv_get_aio_context(bs
);
1489 const BdrvChildClass child_of_bds
= {
1490 .parent_is_bds
= true,
1491 .get_parent_desc
= bdrv_child_get_parent_desc
,
1492 .inherit_options
= bdrv_inherited_options
,
1493 .drained_begin
= bdrv_child_cb_drained_begin
,
1494 .drained_poll
= bdrv_child_cb_drained_poll
,
1495 .drained_end
= bdrv_child_cb_drained_end
,
1496 .attach
= bdrv_child_cb_attach
,
1497 .detach
= bdrv_child_cb_detach
,
1498 .inactivate
= bdrv_child_cb_inactivate
,
1499 .change_aio_ctx
= bdrv_child_cb_change_aio_ctx
,
1500 .update_filename
= bdrv_child_cb_update_filename
,
1501 .get_parent_aio_context
= child_of_bds_get_parent_aio_context
,
1504 AioContext
*bdrv_child_get_parent_aio_context(BdrvChild
*c
)
1507 return c
->klass
->get_parent_aio_context(c
);
1510 static int bdrv_open_flags(BlockDriverState
*bs
, int flags
)
1512 int open_flags
= flags
;
1513 GLOBAL_STATE_CODE();
1516 * Clear flags that are internal to the block layer before opening the
1519 open_flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_PROTOCOL
);
1524 static void update_flags_from_options(int *flags
, QemuOpts
*opts
)
1526 GLOBAL_STATE_CODE();
1528 *flags
&= ~(BDRV_O_CACHE_MASK
| BDRV_O_RDWR
| BDRV_O_AUTO_RDONLY
);
1530 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_NO_FLUSH
, false)) {
1531 *flags
|= BDRV_O_NO_FLUSH
;
1534 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_CACHE_DIRECT
, false)) {
1535 *flags
|= BDRV_O_NOCACHE
;
1538 if (!qemu_opt_get_bool_del(opts
, BDRV_OPT_READ_ONLY
, false)) {
1539 *flags
|= BDRV_O_RDWR
;
1542 if (qemu_opt_get_bool_del(opts
, BDRV_OPT_AUTO_READ_ONLY
, false)) {
1543 *flags
|= BDRV_O_AUTO_RDONLY
;
1547 static void update_options_from_flags(QDict
*options
, int flags
)
1549 GLOBAL_STATE_CODE();
1550 if (!qdict_haskey(options
, BDRV_OPT_CACHE_DIRECT
)) {
1551 qdict_put_bool(options
, BDRV_OPT_CACHE_DIRECT
, flags
& BDRV_O_NOCACHE
);
1553 if (!qdict_haskey(options
, BDRV_OPT_CACHE_NO_FLUSH
)) {
1554 qdict_put_bool(options
, BDRV_OPT_CACHE_NO_FLUSH
,
1555 flags
& BDRV_O_NO_FLUSH
);
1557 if (!qdict_haskey(options
, BDRV_OPT_READ_ONLY
)) {
1558 qdict_put_bool(options
, BDRV_OPT_READ_ONLY
, !(flags
& BDRV_O_RDWR
));
1560 if (!qdict_haskey(options
, BDRV_OPT_AUTO_READ_ONLY
)) {
1561 qdict_put_bool(options
, BDRV_OPT_AUTO_READ_ONLY
,
1562 flags
& BDRV_O_AUTO_RDONLY
);
1566 static void bdrv_assign_node_name(BlockDriverState
*bs
,
1567 const char *node_name
,
1570 char *gen_node_name
= NULL
;
1571 GLOBAL_STATE_CODE();
1574 node_name
= gen_node_name
= id_generate(ID_BLOCK
);
1575 } else if (!id_wellformed(node_name
)) {
1577 * Check for empty string or invalid characters, but not if it is
1578 * generated (generated names use characters not available to the user)
1580 error_setg(errp
, "Invalid node-name: '%s'", node_name
);
1584 /* takes care of avoiding namespaces collisions */
1585 if (blk_by_name(node_name
)) {
1586 error_setg(errp
, "node-name=%s is conflicting with a device id",
1591 /* takes care of avoiding duplicates node names */
1592 if (bdrv_find_node(node_name
)) {
1593 error_setg(errp
, "Duplicate nodes with node-name='%s'", node_name
);
1597 /* Make sure that the node name isn't truncated */
1598 if (strlen(node_name
) >= sizeof(bs
->node_name
)) {
1599 error_setg(errp
, "Node name too long");
1603 /* copy node name into the bs and insert it into the graph list */
1604 pstrcpy(bs
->node_name
, sizeof(bs
->node_name
), node_name
);
1605 QTAILQ_INSERT_TAIL(&graph_bdrv_states
, bs
, node_list
);
1607 g_free(gen_node_name
);
1611 * The caller must always hold @bs AioContext lock, because this function calls
1612 * bdrv_refresh_total_sectors() which polls when called from non-coroutine
1615 static int no_coroutine_fn GRAPH_UNLOCKED
1616 bdrv_open_driver(BlockDriverState
*bs
, BlockDriver
*drv
, const char *node_name
,
1617 QDict
*options
, int open_flags
, Error
**errp
)
1620 Error
*local_err
= NULL
;
1622 GLOBAL_STATE_CODE();
1624 bdrv_assign_node_name(bs
, node_name
, &local_err
);
1626 error_propagate(errp
, local_err
);
1631 bs
->opaque
= g_malloc0(drv
->instance_size
);
1633 if (drv
->bdrv_file_open
) {
1634 assert(!drv
->bdrv_needs_filename
|| bs
->filename
[0]);
1635 ret
= drv
->bdrv_file_open(bs
, options
, open_flags
, &local_err
);
1636 } else if (drv
->bdrv_open
) {
1637 ret
= drv
->bdrv_open(bs
, options
, open_flags
, &local_err
);
1644 error_propagate(errp
, local_err
);
1645 } else if (bs
->filename
[0]) {
1646 error_setg_errno(errp
, -ret
, "Could not open '%s'", bs
->filename
);
1648 error_setg_errno(errp
, -ret
, "Could not open image");
1653 assert(!(bs
->supported_read_flags
& ~BDRV_REQ_MASK
));
1654 assert(!(bs
->supported_write_flags
& ~BDRV_REQ_MASK
));
1657 * Always allow the BDRV_REQ_REGISTERED_BUF optimization hint. This saves
1658 * drivers that pass read/write requests through to a child the trouble of
1659 * declaring support explicitly.
1661 * Drivers must not propagate this flag accidentally when they initiate I/O
1662 * to a bounce buffer. That case should be rare though.
1664 bs
->supported_read_flags
|= BDRV_REQ_REGISTERED_BUF
;
1665 bs
->supported_write_flags
|= BDRV_REQ_REGISTERED_BUF
;
1667 /* Get the context after .bdrv_open, it can change the context */
1668 ctx
= bdrv_get_aio_context(bs
);
1669 aio_context_acquire(ctx
);
1671 ret
= bdrv_refresh_total_sectors(bs
, bs
->total_sectors
);
1673 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
1674 aio_context_release(ctx
);
1678 bdrv_graph_rdlock_main_loop();
1679 bdrv_refresh_limits(bs
, NULL
, &local_err
);
1680 bdrv_graph_rdunlock_main_loop();
1681 aio_context_release(ctx
);
1684 error_propagate(errp
, local_err
);
1688 assert(bdrv_opt_mem_align(bs
) != 0);
1689 assert(bdrv_min_mem_align(bs
) != 0);
1690 assert(is_power_of_2(bs
->bl
.request_alignment
));
1692 for (i
= 0; i
< bs
->quiesce_counter
; i
++) {
1693 if (drv
->bdrv_drain_begin
) {
1694 drv
->bdrv_drain_begin(bs
);
1701 if (bs
->file
!= NULL
) {
1702 bdrv_unref_child(bs
, bs
->file
);
1711 * Create and open a block node.
1713 * @options is a QDict of options to pass to the block drivers, or NULL for an
1714 * empty set of options. The reference to the QDict belongs to the block layer
1715 * after the call (even on failure), so if the caller intends to reuse the
1716 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
1718 BlockDriverState
*bdrv_new_open_driver_opts(BlockDriver
*drv
,
1719 const char *node_name
,
1720 QDict
*options
, int flags
,
1723 BlockDriverState
*bs
;
1726 GLOBAL_STATE_CODE();
1729 bs
->open_flags
= flags
;
1730 bs
->options
= options
?: qdict_new();
1731 bs
->explicit_options
= qdict_clone_shallow(bs
->options
);
1734 update_options_from_flags(bs
->options
, flags
);
1736 ret
= bdrv_open_driver(bs
, drv
, node_name
, bs
->options
, flags
, errp
);
1738 qobject_unref(bs
->explicit_options
);
1739 bs
->explicit_options
= NULL
;
1740 qobject_unref(bs
->options
);
1749 /* Create and open a block node. */
1750 BlockDriverState
*bdrv_new_open_driver(BlockDriver
*drv
, const char *node_name
,
1751 int flags
, Error
**errp
)
1753 GLOBAL_STATE_CODE();
1754 return bdrv_new_open_driver_opts(drv
, node_name
, NULL
, flags
, errp
);
1757 QemuOptsList bdrv_runtime_opts
= {
1758 .name
= "bdrv_common",
1759 .head
= QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts
.head
),
1762 .name
= "node-name",
1763 .type
= QEMU_OPT_STRING
,
1764 .help
= "Node name of the block device node",
1768 .type
= QEMU_OPT_STRING
,
1769 .help
= "Block driver to use for the node",
1772 .name
= BDRV_OPT_CACHE_DIRECT
,
1773 .type
= QEMU_OPT_BOOL
,
1774 .help
= "Bypass software writeback cache on the host",
1777 .name
= BDRV_OPT_CACHE_NO_FLUSH
,
1778 .type
= QEMU_OPT_BOOL
,
1779 .help
= "Ignore flush requests",
1782 .name
= BDRV_OPT_READ_ONLY
,
1783 .type
= QEMU_OPT_BOOL
,
1784 .help
= "Node is opened in read-only mode",
1787 .name
= BDRV_OPT_AUTO_READ_ONLY
,
1788 .type
= QEMU_OPT_BOOL
,
1789 .help
= "Node can become read-only if opening read-write fails",
1792 .name
= "detect-zeroes",
1793 .type
= QEMU_OPT_STRING
,
1794 .help
= "try to optimize zero writes (off, on, unmap)",
1797 .name
= BDRV_OPT_DISCARD
,
1798 .type
= QEMU_OPT_STRING
,
1799 .help
= "discard operation (ignore/off, unmap/on)",
1802 .name
= BDRV_OPT_FORCE_SHARE
,
1803 .type
= QEMU_OPT_BOOL
,
1804 .help
= "always accept other writers (default: off)",
1806 { /* end of list */ }
1810 QemuOptsList bdrv_create_opts_simple
= {
1811 .name
= "simple-create-opts",
1812 .head
= QTAILQ_HEAD_INITIALIZER(bdrv_create_opts_simple
.head
),
1815 .name
= BLOCK_OPT_SIZE
,
1816 .type
= QEMU_OPT_SIZE
,
1817 .help
= "Virtual disk size"
1820 .name
= BLOCK_OPT_PREALLOC
,
1821 .type
= QEMU_OPT_STRING
,
1822 .help
= "Preallocation mode (allowed values: off)"
1824 { /* end of list */ }
1829 * Common part for opening disk images and files
1831 * Removes all processed options from *options.
1833 static int bdrv_open_common(BlockDriverState
*bs
, BlockBackend
*file
,
1834 QDict
*options
, Error
**errp
)
1836 int ret
, open_flags
;
1837 const char *filename
;
1838 const char *driver_name
= NULL
;
1839 const char *node_name
= NULL
;
1840 const char *discard
;
1843 Error
*local_err
= NULL
;
1846 assert(bs
->file
== NULL
);
1847 assert(options
!= NULL
&& bs
->options
!= options
);
1848 GLOBAL_STATE_CODE();
1850 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
1851 if (!qemu_opts_absorb_qdict(opts
, options
, errp
)) {
1856 update_flags_from_options(&bs
->open_flags
, opts
);
1858 driver_name
= qemu_opt_get(opts
, "driver");
1859 drv
= bdrv_find_format(driver_name
);
1860 assert(drv
!= NULL
);
1862 bs
->force_share
= qemu_opt_get_bool(opts
, BDRV_OPT_FORCE_SHARE
, false);
1864 if (bs
->force_share
&& (bs
->open_flags
& BDRV_O_RDWR
)) {
1866 BDRV_OPT_FORCE_SHARE
1867 "=on can only be used with read-only images");
1873 bdrv_refresh_filename(blk_bs(file
));
1874 filename
= blk_bs(file
)->filename
;
1877 * Caution: while qdict_get_try_str() is fine, getting
1878 * non-string types would require more care. When @options
1879 * come from -blockdev or blockdev_add, its members are typed
1880 * according to the QAPI schema, but when they come from
1881 * -drive, they're all QString.
1883 filename
= qdict_get_try_str(options
, "filename");
1886 if (drv
->bdrv_needs_filename
&& (!filename
|| !filename
[0])) {
1887 error_setg(errp
, "The '%s' block driver requires a file name",
1893 trace_bdrv_open_common(bs
, filename
?: "", bs
->open_flags
,
1896 ro
= bdrv_is_read_only(bs
);
1898 if (use_bdrv_whitelist
&& !bdrv_is_whitelisted(drv
, ro
)) {
1899 if (!ro
&& bdrv_is_whitelisted(drv
, true)) {
1900 ret
= bdrv_apply_auto_read_only(bs
, NULL
, NULL
);
1906 !ro
&& bdrv_is_whitelisted(drv
, true)
1907 ? "Driver '%s' can only be used for read-only devices"
1908 : "Driver '%s' is not whitelisted",
1914 /* bdrv_new() and bdrv_close() make it so */
1915 assert(qatomic_read(&bs
->copy_on_read
) == 0);
1917 if (bs
->open_flags
& BDRV_O_COPY_ON_READ
) {
1919 bdrv_enable_copy_on_read(bs
);
1921 error_setg(errp
, "Can't use copy-on-read on read-only device");
1927 discard
= qemu_opt_get(opts
, BDRV_OPT_DISCARD
);
1928 if (discard
!= NULL
) {
1929 if (bdrv_parse_discard_flags(discard
, &bs
->open_flags
) != 0) {
1930 error_setg(errp
, "Invalid discard option");
1937 bdrv_parse_detect_zeroes(opts
, bs
->open_flags
, &local_err
);
1939 error_propagate(errp
, local_err
);
1944 if (filename
!= NULL
) {
1945 pstrcpy(bs
->filename
, sizeof(bs
->filename
), filename
);
1947 bs
->filename
[0] = '\0';
1949 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
), bs
->filename
);
1951 /* Open the image, either directly or using a protocol */
1952 open_flags
= bdrv_open_flags(bs
, bs
->open_flags
);
1953 node_name
= qemu_opt_get(opts
, "node-name");
1955 assert(!drv
->bdrv_file_open
|| file
== NULL
);
1956 ret
= bdrv_open_driver(bs
, drv
, node_name
, options
, open_flags
, errp
);
1961 qemu_opts_del(opts
);
1965 qemu_opts_del(opts
);
1969 static QDict
*parse_json_filename(const char *filename
, Error
**errp
)
1971 QObject
*options_obj
;
1974 GLOBAL_STATE_CODE();
1976 ret
= strstart(filename
, "json:", &filename
);
1979 options_obj
= qobject_from_json(filename
, errp
);
1981 error_prepend(errp
, "Could not parse the JSON options: ");
1985 options
= qobject_to(QDict
, options_obj
);
1987 qobject_unref(options_obj
);
1988 error_setg(errp
, "Invalid JSON object given");
1992 qdict_flatten(options
);
1997 static void parse_json_protocol(QDict
*options
, const char **pfilename
,
2000 QDict
*json_options
;
2001 Error
*local_err
= NULL
;
2002 GLOBAL_STATE_CODE();
2004 /* Parse json: pseudo-protocol */
2005 if (!*pfilename
|| !g_str_has_prefix(*pfilename
, "json:")) {
2009 json_options
= parse_json_filename(*pfilename
, &local_err
);
2011 error_propagate(errp
, local_err
);
2015 /* Options given in the filename have lower priority than options
2016 * specified directly */
2017 qdict_join(options
, json_options
, false);
2018 qobject_unref(json_options
);
2023 * Fills in default options for opening images and converts the legacy
2024 * filename/flags pair to option QDict entries.
2025 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
2026 * block driver has been specified explicitly.
2028 static int bdrv_fill_options(QDict
**options
, const char *filename
,
2029 int *flags
, Error
**errp
)
2031 const char *drvname
;
2032 bool protocol
= *flags
& BDRV_O_PROTOCOL
;
2033 bool parse_filename
= false;
2034 BlockDriver
*drv
= NULL
;
2035 Error
*local_err
= NULL
;
2037 GLOBAL_STATE_CODE();
2040 * Caution: while qdict_get_try_str() is fine, getting non-string
2041 * types would require more care. When @options come from
2042 * -blockdev or blockdev_add, its members are typed according to
2043 * the QAPI schema, but when they come from -drive, they're all
2046 drvname
= qdict_get_try_str(*options
, "driver");
2048 drv
= bdrv_find_format(drvname
);
2050 error_setg(errp
, "Unknown driver '%s'", drvname
);
2053 /* If the user has explicitly specified the driver, this choice should
2054 * override the BDRV_O_PROTOCOL flag */
2055 protocol
= drv
->bdrv_file_open
;
2059 *flags
|= BDRV_O_PROTOCOL
;
2061 *flags
&= ~BDRV_O_PROTOCOL
;
2064 /* Translate cache options from flags into options */
2065 update_options_from_flags(*options
, *flags
);
2067 /* Fetch the file name from the options QDict if necessary */
2068 if (protocol
&& filename
) {
2069 if (!qdict_haskey(*options
, "filename")) {
2070 qdict_put_str(*options
, "filename", filename
);
2071 parse_filename
= true;
2073 error_setg(errp
, "Can't specify 'file' and 'filename' options at "
2079 /* Find the right block driver */
2080 /* See cautionary note on accessing @options above */
2081 filename
= qdict_get_try_str(*options
, "filename");
2083 if (!drvname
&& protocol
) {
2085 drv
= bdrv_find_protocol(filename
, parse_filename
, errp
);
2090 drvname
= drv
->format_name
;
2091 qdict_put_str(*options
, "driver", drvname
);
2093 error_setg(errp
, "Must specify either driver or file");
2098 assert(drv
|| !protocol
);
2100 /* Driver-specific filename parsing */
2101 if (drv
&& drv
->bdrv_parse_filename
&& parse_filename
) {
2102 drv
->bdrv_parse_filename(filename
, *options
, &local_err
);
2104 error_propagate(errp
, local_err
);
2108 if (!drv
->bdrv_needs_filename
) {
2109 qdict_del(*options
, "filename");
2116 typedef struct BlockReopenQueueEntry
{
2118 BDRVReopenState state
;
2119 QTAILQ_ENTRY(BlockReopenQueueEntry
) entry
;
2120 } BlockReopenQueueEntry
;
2123 * Return the flags that @bs will have after the reopens in @q have
2124 * successfully completed. If @q is NULL (or @bs is not contained in @q),
2125 * return the current flags.
2127 static int bdrv_reopen_get_flags(BlockReopenQueue
*q
, BlockDriverState
*bs
)
2129 BlockReopenQueueEntry
*entry
;
2132 QTAILQ_FOREACH(entry
, q
, entry
) {
2133 if (entry
->state
.bs
== bs
) {
2134 return entry
->state
.flags
;
2139 return bs
->open_flags
;
2142 /* Returns whether the image file can be written to after the reopen queue @q
2143 * has been successfully applied, or right now if @q is NULL. */
2144 static bool bdrv_is_writable_after_reopen(BlockDriverState
*bs
,
2145 BlockReopenQueue
*q
)
2147 int flags
= bdrv_reopen_get_flags(q
, bs
);
2149 return (flags
& (BDRV_O_RDWR
| BDRV_O_INACTIVE
)) == BDRV_O_RDWR
;
2153 * Return whether the BDS can be written to. This is not necessarily
2154 * the same as !bdrv_is_read_only(bs), as inactivated images may not
2155 * be written to but do not count as read-only images.
2157 bool bdrv_is_writable(BlockDriverState
*bs
)
2160 return bdrv_is_writable_after_reopen(bs
, NULL
);
2163 static char *bdrv_child_user_desc(BdrvChild
*c
)
2165 GLOBAL_STATE_CODE();
2166 return c
->klass
->get_parent_desc(c
);
2170 * Check that @a allows everything that @b needs. @a and @b must reference same
2173 static bool bdrv_a_allow_b(BdrvChild
*a
, BdrvChild
*b
, Error
**errp
)
2175 const char *child_bs_name
;
2176 g_autofree
char *a_user
= NULL
;
2177 g_autofree
char *b_user
= NULL
;
2178 g_autofree
char *perms
= NULL
;
2181 assert(a
->bs
== b
->bs
);
2182 GLOBAL_STATE_CODE();
2184 if ((b
->perm
& a
->shared_perm
) == b
->perm
) {
2188 child_bs_name
= bdrv_get_node_name(b
->bs
);
2189 a_user
= bdrv_child_user_desc(a
);
2190 b_user
= bdrv_child_user_desc(b
);
2191 perms
= bdrv_perm_names(b
->perm
& ~a
->shared_perm
);
2193 error_setg(errp
, "Permission conflict on node '%s': permissions '%s' are "
2194 "both required by %s (uses node '%s' as '%s' child) and "
2195 "unshared by %s (uses node '%s' as '%s' child).",
2196 child_bs_name
, perms
,
2197 b_user
, child_bs_name
, b
->name
,
2198 a_user
, child_bs_name
, a
->name
);
2203 static bool bdrv_parent_perms_conflict(BlockDriverState
*bs
, Error
**errp
)
2206 GLOBAL_STATE_CODE();
2209 * During the loop we'll look at each pair twice. That's correct because
2210 * bdrv_a_allow_b() is asymmetric and we should check each pair in both
2213 QLIST_FOREACH(a
, &bs
->parents
, next_parent
) {
2214 QLIST_FOREACH(b
, &bs
->parents
, next_parent
) {
2219 if (!bdrv_a_allow_b(a
, b
, errp
)) {
2228 static void bdrv_child_perm(BlockDriverState
*bs
, BlockDriverState
*child_bs
,
2229 BdrvChild
*c
, BdrvChildRole role
,
2230 BlockReopenQueue
*reopen_queue
,
2231 uint64_t parent_perm
, uint64_t parent_shared
,
2232 uint64_t *nperm
, uint64_t *nshared
)
2234 assert(bs
->drv
&& bs
->drv
->bdrv_child_perm
);
2235 GLOBAL_STATE_CODE();
2236 bs
->drv
->bdrv_child_perm(bs
, c
, role
, reopen_queue
,
2237 parent_perm
, parent_shared
,
2239 /* TODO Take force_share from reopen_queue */
2240 if (child_bs
&& child_bs
->force_share
) {
2241 *nshared
= BLK_PERM_ALL
;
2246 * Adds the whole subtree of @bs (including @bs itself) to the @list (except for
2247 * nodes that are already in the @list, of course) so that final list is
2248 * topologically sorted. Return the result (GSList @list object is updated, so
2249 * don't use old reference after function call).
2251 * On function start @list must be already topologically sorted and for any node
2252 * in the @list the whole subtree of the node must be in the @list as well. The
2253 * simplest way to satisfy this criteria: use only result of
2254 * bdrv_topological_dfs() or NULL as @list parameter.
2256 static GSList
*bdrv_topological_dfs(GSList
*list
, GHashTable
*found
,
2257 BlockDriverState
*bs
)
2260 g_autoptr(GHashTable
) local_found
= NULL
;
2262 GLOBAL_STATE_CODE();
2266 found
= local_found
= g_hash_table_new(NULL
, NULL
);
2269 if (g_hash_table_contains(found
, bs
)) {
2272 g_hash_table_add(found
, bs
);
2274 QLIST_FOREACH(child
, &bs
->children
, next
) {
2275 list
= bdrv_topological_dfs(list
, found
, child
->bs
);
2278 return g_slist_prepend(list
, bs
);
2281 typedef struct BdrvChildSetPermState
{
2284 uint64_t old_shared_perm
;
2285 } BdrvChildSetPermState
;
2287 static void bdrv_child_set_perm_abort(void *opaque
)
2289 BdrvChildSetPermState
*s
= opaque
;
2291 GLOBAL_STATE_CODE();
2293 s
->child
->perm
= s
->old_perm
;
2294 s
->child
->shared_perm
= s
->old_shared_perm
;
2297 static TransactionActionDrv bdrv_child_set_pem_drv
= {
2298 .abort
= bdrv_child_set_perm_abort
,
2302 static void bdrv_child_set_perm(BdrvChild
*c
, uint64_t perm
,
2303 uint64_t shared
, Transaction
*tran
)
2305 BdrvChildSetPermState
*s
= g_new(BdrvChildSetPermState
, 1);
2306 GLOBAL_STATE_CODE();
2308 *s
= (BdrvChildSetPermState
) {
2310 .old_perm
= c
->perm
,
2311 .old_shared_perm
= c
->shared_perm
,
2315 c
->shared_perm
= shared
;
2317 tran_add(tran
, &bdrv_child_set_pem_drv
, s
);
2320 static void bdrv_drv_set_perm_commit(void *opaque
)
2322 BlockDriverState
*bs
= opaque
;
2323 uint64_t cumulative_perms
, cumulative_shared_perms
;
2324 GLOBAL_STATE_CODE();
2326 if (bs
->drv
->bdrv_set_perm
) {
2327 bdrv_get_cumulative_perm(bs
, &cumulative_perms
,
2328 &cumulative_shared_perms
);
2329 bs
->drv
->bdrv_set_perm(bs
, cumulative_perms
, cumulative_shared_perms
);
2333 static void bdrv_drv_set_perm_abort(void *opaque
)
2335 BlockDriverState
*bs
= opaque
;
2336 GLOBAL_STATE_CODE();
2338 if (bs
->drv
->bdrv_abort_perm_update
) {
2339 bs
->drv
->bdrv_abort_perm_update(bs
);
2343 TransactionActionDrv bdrv_drv_set_perm_drv
= {
2344 .abort
= bdrv_drv_set_perm_abort
,
2345 .commit
= bdrv_drv_set_perm_commit
,
2348 static int bdrv_drv_set_perm(BlockDriverState
*bs
, uint64_t perm
,
2349 uint64_t shared_perm
, Transaction
*tran
,
2352 GLOBAL_STATE_CODE();
2357 if (bs
->drv
->bdrv_check_perm
) {
2358 int ret
= bs
->drv
->bdrv_check_perm(bs
, perm
, shared_perm
, errp
);
2365 tran_add(tran
, &bdrv_drv_set_perm_drv
, bs
);
2371 typedef struct BdrvReplaceChildState
{
2373 BlockDriverState
*old_bs
;
2374 } BdrvReplaceChildState
;
2376 static void bdrv_replace_child_commit(void *opaque
)
2378 BdrvReplaceChildState
*s
= opaque
;
2379 GLOBAL_STATE_CODE();
2381 bdrv_unref(s
->old_bs
);
2384 static void bdrv_replace_child_abort(void *opaque
)
2386 BdrvReplaceChildState
*s
= opaque
;
2387 BlockDriverState
*new_bs
= s
->child
->bs
;
2389 GLOBAL_STATE_CODE();
2390 /* old_bs reference is transparently moved from @s to @s->child */
2391 if (!s
->child
->bs
) {
2393 * The parents were undrained when removing old_bs from the child. New
2394 * requests can't have been made, though, because the child was empty.
2396 * TODO Make bdrv_replace_child_noperm() transactionable to avoid
2397 * undraining the parent in the first place. Once this is done, having
2398 * new_bs drained when calling bdrv_replace_child_tran() is not a
2399 * requirement any more.
2401 bdrv_parent_drained_begin_single(s
->child
);
2402 assert(!bdrv_parent_drained_poll_single(s
->child
));
2404 assert(s
->child
->quiesced_parent
);
2405 bdrv_replace_child_noperm(s
->child
, s
->old_bs
);
2409 static TransactionActionDrv bdrv_replace_child_drv
= {
2410 .commit
= bdrv_replace_child_commit
,
2411 .abort
= bdrv_replace_child_abort
,
2416 * bdrv_replace_child_tran
2418 * Note: real unref of old_bs is done only on commit.
2420 * Both @child->bs and @new_bs (if non-NULL) must be drained. @new_bs must be
2421 * kept drained until the transaction is completed.
2423 * The function doesn't update permissions, caller is responsible for this.
2425 static void bdrv_replace_child_tran(BdrvChild
*child
, BlockDriverState
*new_bs
,
2428 BdrvReplaceChildState
*s
= g_new(BdrvReplaceChildState
, 1);
2430 assert(child
->quiesced_parent
);
2431 assert(!new_bs
|| new_bs
->quiesce_counter
);
2433 *s
= (BdrvReplaceChildState
) {
2435 .old_bs
= child
->bs
,
2437 tran_add(tran
, &bdrv_replace_child_drv
, s
);
2442 bdrv_replace_child_noperm(child
, new_bs
);
2443 /* old_bs reference is transparently moved from @child to @s */
2447 * Refresh permissions in @bs subtree. The function is intended to be called
2448 * after some graph modification that was done without permission update.
2450 static int bdrv_node_refresh_perm(BlockDriverState
*bs
, BlockReopenQueue
*q
,
2451 Transaction
*tran
, Error
**errp
)
2453 BlockDriver
*drv
= bs
->drv
;
2456 uint64_t cumulative_perms
, cumulative_shared_perms
;
2457 GLOBAL_STATE_CODE();
2459 bdrv_get_cumulative_perm(bs
, &cumulative_perms
, &cumulative_shared_perms
);
2461 /* Write permissions never work with read-only images */
2462 if ((cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) &&
2463 !bdrv_is_writable_after_reopen(bs
, q
))
2465 if (!bdrv_is_writable_after_reopen(bs
, NULL
)) {
2466 error_setg(errp
, "Block node is read-only");
2468 error_setg(errp
, "Read-only block node '%s' cannot support "
2469 "read-write users", bdrv_get_node_name(bs
));
2476 * Unaligned requests will automatically be aligned to bl.request_alignment
2477 * and without RESIZE we can't extend requests to write to space beyond the
2478 * end of the image, so it's required that the image size is aligned.
2480 if ((cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) &&
2481 !(cumulative_perms
& BLK_PERM_RESIZE
))
2483 if ((bs
->total_sectors
* BDRV_SECTOR_SIZE
) % bs
->bl
.request_alignment
) {
2484 error_setg(errp
, "Cannot get 'write' permission without 'resize': "
2485 "Image size is not a multiple of request "
2491 /* Check this node */
2496 ret
= bdrv_drv_set_perm(bs
, cumulative_perms
, cumulative_shared_perms
, tran
,
2502 /* Drivers that never have children can omit .bdrv_child_perm() */
2503 if (!drv
->bdrv_child_perm
) {
2504 assert(QLIST_EMPTY(&bs
->children
));
2508 /* Check all children */
2509 QLIST_FOREACH(c
, &bs
->children
, next
) {
2510 uint64_t cur_perm
, cur_shared
;
2512 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, q
,
2513 cumulative_perms
, cumulative_shared_perms
,
2514 &cur_perm
, &cur_shared
);
2515 bdrv_child_set_perm(c
, cur_perm
, cur_shared
, tran
);
2522 * @list is a product of bdrv_topological_dfs() (may be called several times) -
2523 * a topologically sorted subgraph.
2525 static int bdrv_do_refresh_perms(GSList
*list
, BlockReopenQueue
*q
,
2526 Transaction
*tran
, Error
**errp
)
2529 BlockDriverState
*bs
;
2530 GLOBAL_STATE_CODE();
2532 for ( ; list
; list
= list
->next
) {
2535 if (bdrv_parent_perms_conflict(bs
, errp
)) {
2539 ret
= bdrv_node_refresh_perm(bs
, q
, tran
, errp
);
2549 * @list is any list of nodes. List is completed by all subtrees and
2550 * topologically sorted. It's not a problem if some node occurs in the @list
2553 static int bdrv_list_refresh_perms(GSList
*list
, BlockReopenQueue
*q
,
2554 Transaction
*tran
, Error
**errp
)
2556 g_autoptr(GHashTable
) found
= g_hash_table_new(NULL
, NULL
);
2557 g_autoptr(GSList
) refresh_list
= NULL
;
2559 for ( ; list
; list
= list
->next
) {
2560 refresh_list
= bdrv_topological_dfs(refresh_list
, found
, list
->data
);
2563 return bdrv_do_refresh_perms(refresh_list
, q
, tran
, errp
);
2566 void bdrv_get_cumulative_perm(BlockDriverState
*bs
, uint64_t *perm
,
2567 uint64_t *shared_perm
)
2570 uint64_t cumulative_perms
= 0;
2571 uint64_t cumulative_shared_perms
= BLK_PERM_ALL
;
2573 GLOBAL_STATE_CODE();
2575 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
2576 cumulative_perms
|= c
->perm
;
2577 cumulative_shared_perms
&= c
->shared_perm
;
2580 *perm
= cumulative_perms
;
2581 *shared_perm
= cumulative_shared_perms
;
2584 char *bdrv_perm_names(uint64_t perm
)
2590 { BLK_PERM_CONSISTENT_READ
, "consistent read" },
2591 { BLK_PERM_WRITE
, "write" },
2592 { BLK_PERM_WRITE_UNCHANGED
, "write unchanged" },
2593 { BLK_PERM_RESIZE
, "resize" },
2597 GString
*result
= g_string_sized_new(30);
2598 struct perm_name
*p
;
2600 for (p
= permissions
; p
->name
; p
++) {
2601 if (perm
& p
->perm
) {
2602 if (result
->len
> 0) {
2603 g_string_append(result
, ", ");
2605 g_string_append(result
, p
->name
);
2609 return g_string_free(result
, FALSE
);
2613 /* @tran is allowed to be NULL. In this case no rollback is possible */
2614 static int bdrv_refresh_perms(BlockDriverState
*bs
, Transaction
*tran
,
2618 Transaction
*local_tran
= NULL
;
2619 g_autoptr(GSList
) list
= bdrv_topological_dfs(NULL
, NULL
, bs
);
2620 GLOBAL_STATE_CODE();
2623 tran
= local_tran
= tran_new();
2626 ret
= bdrv_do_refresh_perms(list
, NULL
, tran
, errp
);
2629 tran_finalize(local_tran
, ret
);
2635 int bdrv_child_try_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
,
2638 Error
*local_err
= NULL
;
2639 Transaction
*tran
= tran_new();
2642 GLOBAL_STATE_CODE();
2644 bdrv_child_set_perm(c
, perm
, shared
, tran
);
2646 ret
= bdrv_refresh_perms(c
->bs
, tran
, &local_err
);
2648 tran_finalize(tran
, ret
);
2651 if ((perm
& ~c
->perm
) || (c
->shared_perm
& ~shared
)) {
2652 /* tighten permissions */
2653 error_propagate(errp
, local_err
);
2656 * Our caller may intend to only loosen restrictions and
2657 * does not expect this function to fail. Errors are not
2658 * fatal in such a case, so we can just hide them from our
2661 error_free(local_err
);
2669 int bdrv_child_refresh_perms(BlockDriverState
*bs
, BdrvChild
*c
, Error
**errp
)
2671 uint64_t parent_perms
, parent_shared
;
2672 uint64_t perms
, shared
;
2674 GLOBAL_STATE_CODE();
2676 bdrv_get_cumulative_perm(bs
, &parent_perms
, &parent_shared
);
2677 bdrv_child_perm(bs
, c
->bs
, c
, c
->role
, NULL
,
2678 parent_perms
, parent_shared
, &perms
, &shared
);
2680 return bdrv_child_try_set_perm(c
, perms
, shared
, errp
);
2684 * Default implementation for .bdrv_child_perm() for block filters:
2685 * Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED, and RESIZE to the
2688 static void bdrv_filter_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2690 BlockReopenQueue
*reopen_queue
,
2691 uint64_t perm
, uint64_t shared
,
2692 uint64_t *nperm
, uint64_t *nshared
)
2694 GLOBAL_STATE_CODE();
2695 *nperm
= perm
& DEFAULT_PERM_PASSTHROUGH
;
2696 *nshared
= (shared
& DEFAULT_PERM_PASSTHROUGH
) | DEFAULT_PERM_UNCHANGED
;
2699 static void bdrv_default_perms_for_cow(BlockDriverState
*bs
, BdrvChild
*c
,
2701 BlockReopenQueue
*reopen_queue
,
2702 uint64_t perm
, uint64_t shared
,
2703 uint64_t *nperm
, uint64_t *nshared
)
2705 assert(role
& BDRV_CHILD_COW
);
2706 GLOBAL_STATE_CODE();
2709 * We want consistent read from backing files if the parent needs it.
2710 * No other operations are performed on backing files.
2712 perm
&= BLK_PERM_CONSISTENT_READ
;
2715 * If the parent can deal with changing data, we're okay with a
2716 * writable and resizable backing file.
2717 * TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too?
2719 if (shared
& BLK_PERM_WRITE
) {
2720 shared
= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2725 shared
|= BLK_PERM_CONSISTENT_READ
| BLK_PERM_WRITE_UNCHANGED
;
2727 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
2728 shared
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2735 static void bdrv_default_perms_for_storage(BlockDriverState
*bs
, BdrvChild
*c
,
2737 BlockReopenQueue
*reopen_queue
,
2738 uint64_t perm
, uint64_t shared
,
2739 uint64_t *nperm
, uint64_t *nshared
)
2743 GLOBAL_STATE_CODE();
2744 assert(role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_DATA
));
2746 flags
= bdrv_reopen_get_flags(reopen_queue
, bs
);
2749 * Apart from the modifications below, the same permissions are
2750 * forwarded and left alone as for filters
2752 bdrv_filter_default_perms(bs
, c
, role
, reopen_queue
,
2753 perm
, shared
, &perm
, &shared
);
2755 if (role
& BDRV_CHILD_METADATA
) {
2756 /* Format drivers may touch metadata even if the guest doesn't write */
2757 if (bdrv_is_writable_after_reopen(bs
, reopen_queue
)) {
2758 perm
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2762 * bs->file always needs to be consistent because of the
2763 * metadata. We can never allow other users to resize or write
2766 if (!(flags
& BDRV_O_NO_IO
)) {
2767 perm
|= BLK_PERM_CONSISTENT_READ
;
2769 shared
&= ~(BLK_PERM_WRITE
| BLK_PERM_RESIZE
);
2772 if (role
& BDRV_CHILD_DATA
) {
2774 * Technically, everything in this block is a subset of the
2775 * BDRV_CHILD_METADATA path taken above, and so this could
2776 * be an "else if" branch. However, that is not obvious, and
2777 * this function is not performance critical, therefore we let
2778 * this be an independent "if".
2782 * We cannot allow other users to resize the file because the
2783 * format driver might have some assumptions about the size
2784 * (e.g. because it is stored in metadata, or because the file
2785 * is split into fixed-size data files).
2787 shared
&= ~BLK_PERM_RESIZE
;
2790 * WRITE_UNCHANGED often cannot be performed as such on the
2791 * data file. For example, the qcow2 driver may still need to
2792 * write copied clusters on copy-on-read.
2794 if (perm
& BLK_PERM_WRITE_UNCHANGED
) {
2795 perm
|= BLK_PERM_WRITE
;
2799 * If the data file is written to, the format driver may
2800 * expect to be able to resize it by writing beyond the EOF.
2802 if (perm
& BLK_PERM_WRITE
) {
2803 perm
|= BLK_PERM_RESIZE
;
2807 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
2808 shared
|= BLK_PERM_WRITE
| BLK_PERM_RESIZE
;
2815 void bdrv_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
2816 BdrvChildRole role
, BlockReopenQueue
*reopen_queue
,
2817 uint64_t perm
, uint64_t shared
,
2818 uint64_t *nperm
, uint64_t *nshared
)
2820 GLOBAL_STATE_CODE();
2821 if (role
& BDRV_CHILD_FILTERED
) {
2822 assert(!(role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
|
2824 bdrv_filter_default_perms(bs
, c
, role
, reopen_queue
,
2825 perm
, shared
, nperm
, nshared
);
2826 } else if (role
& BDRV_CHILD_COW
) {
2827 assert(!(role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
)));
2828 bdrv_default_perms_for_cow(bs
, c
, role
, reopen_queue
,
2829 perm
, shared
, nperm
, nshared
);
2830 } else if (role
& (BDRV_CHILD_METADATA
| BDRV_CHILD_DATA
)) {
2831 bdrv_default_perms_for_storage(bs
, c
, role
, reopen_queue
,
2832 perm
, shared
, nperm
, nshared
);
2834 g_assert_not_reached();
2838 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm
)
2840 static const uint64_t permissions
[] = {
2841 [BLOCK_PERMISSION_CONSISTENT_READ
] = BLK_PERM_CONSISTENT_READ
,
2842 [BLOCK_PERMISSION_WRITE
] = BLK_PERM_WRITE
,
2843 [BLOCK_PERMISSION_WRITE_UNCHANGED
] = BLK_PERM_WRITE_UNCHANGED
,
2844 [BLOCK_PERMISSION_RESIZE
] = BLK_PERM_RESIZE
,
2847 QEMU_BUILD_BUG_ON(ARRAY_SIZE(permissions
) != BLOCK_PERMISSION__MAX
);
2848 QEMU_BUILD_BUG_ON(1UL << ARRAY_SIZE(permissions
) != BLK_PERM_ALL
+ 1);
2850 assert(qapi_perm
< BLOCK_PERMISSION__MAX
);
2852 return permissions
[qapi_perm
];
2856 * Replaces the node that a BdrvChild points to without updating permissions.
2858 * If @new_bs is non-NULL, the parent of @child must already be drained through
2859 * @child and the caller must hold the AioContext lock for @new_bs.
2861 static void bdrv_replace_child_noperm(BdrvChild
*child
,
2862 BlockDriverState
*new_bs
)
2864 BlockDriverState
*old_bs
= child
->bs
;
2865 int new_bs_quiesce_counter
;
2867 assert(!child
->frozen
);
2870 * If we want to change the BdrvChild to point to a drained node as its new
2871 * child->bs, we need to make sure that its new parent is drained, too. In
2872 * other words, either child->quiesce_parent must already be true or we must
2873 * be able to set it and keep the parent's quiesce_counter consistent with
2874 * that, but without polling or starting new requests (this function
2875 * guarantees that it doesn't poll, and starting new requests would be
2876 * against the invariants of drain sections).
2878 * To keep things simple, we pick the first option (child->quiesce_parent
2879 * must already be true). We also generalise the rule a bit to make it
2880 * easier to verify in callers and more likely to be covered in test cases:
2881 * The parent must be quiesced through this child even if new_bs isn't
2882 * currently drained.
2884 * The only exception is for callers that always pass new_bs == NULL. In
2885 * this case, we obviously never need to consider the case of a drained
2886 * new_bs, so we can keep the callers simpler by allowing them not to drain
2889 assert(!new_bs
|| child
->quiesced_parent
);
2890 assert(old_bs
!= new_bs
);
2891 GLOBAL_STATE_CODE();
2893 if (old_bs
&& new_bs
) {
2894 assert(bdrv_get_aio_context(old_bs
) == bdrv_get_aio_context(new_bs
));
2897 /* TODO Pull this up into the callers to avoid polling here */
2898 bdrv_graph_wrlock(new_bs
);
2900 if (child
->klass
->detach
) {
2901 child
->klass
->detach(child
);
2903 QLIST_REMOVE(child
, next_parent
);
2909 QLIST_INSERT_HEAD(&new_bs
->parents
, child
, next_parent
);
2910 if (child
->klass
->attach
) {
2911 child
->klass
->attach(child
);
2914 bdrv_graph_wrunlock();
2917 * If the parent was drained through this BdrvChild previously, but new_bs
2918 * is not drained, allow requests to come in only after the new node has
2921 new_bs_quiesce_counter
= (new_bs
? new_bs
->quiesce_counter
: 0);
2922 if (!new_bs_quiesce_counter
&& child
->quiesced_parent
) {
2923 bdrv_parent_drained_end_single(child
);
2928 * Free the given @child.
2930 * The child must be empty (i.e. `child->bs == NULL`) and it must be
2931 * unused (i.e. not in a children list).
2933 static void bdrv_child_free(BdrvChild
*child
)
2936 GLOBAL_STATE_CODE();
2937 assert(!child
->next
.le_prev
); /* not in children list */
2939 g_free(child
->name
);
2943 typedef struct BdrvAttachChildCommonState
{
2945 AioContext
*old_parent_ctx
;
2946 AioContext
*old_child_ctx
;
2947 } BdrvAttachChildCommonState
;
2949 static void bdrv_attach_child_common_abort(void *opaque
)
2951 BdrvAttachChildCommonState
*s
= opaque
;
2952 BlockDriverState
*bs
= s
->child
->bs
;
2954 GLOBAL_STATE_CODE();
2955 bdrv_replace_child_noperm(s
->child
, NULL
);
2957 if (bdrv_get_aio_context(bs
) != s
->old_child_ctx
) {
2958 bdrv_try_change_aio_context(bs
, s
->old_child_ctx
, NULL
, &error_abort
);
2961 if (bdrv_child_get_parent_aio_context(s
->child
) != s
->old_parent_ctx
) {
2963 GHashTable
*visited
;
2968 /* No need to visit `child`, because it has been detached already */
2969 visited
= g_hash_table_new(NULL
, NULL
);
2970 ret
= s
->child
->klass
->change_aio_ctx(s
->child
, s
->old_parent_ctx
,
2971 visited
, tran
, &error_abort
);
2972 g_hash_table_destroy(visited
);
2974 /* transaction is supposed to always succeed */
2975 assert(ret
== true);
2980 bdrv_child_free(s
->child
);
2983 static TransactionActionDrv bdrv_attach_child_common_drv
= {
2984 .abort
= bdrv_attach_child_common_abort
,
2989 * Common part of attaching bdrv child to bs or to blk or to job
2991 * Function doesn't update permissions, caller is responsible for this.
2993 * Returns new created child.
2995 * The caller must hold the AioContext lock for @child_bs. Both @parent_bs and
2996 * @child_bs can move to a different AioContext in this function. Callers must
2997 * make sure that their AioContext locking is still correct after this.
2999 static BdrvChild
*bdrv_attach_child_common(BlockDriverState
*child_bs
,
3000 const char *child_name
,
3001 const BdrvChildClass
*child_class
,
3002 BdrvChildRole child_role
,
3003 uint64_t perm
, uint64_t shared_perm
,
3005 Transaction
*tran
, Error
**errp
)
3007 BdrvChild
*new_child
;
3008 AioContext
*parent_ctx
, *new_child_ctx
;
3009 AioContext
*child_ctx
= bdrv_get_aio_context(child_bs
);
3011 assert(child_class
->get_parent_desc
);
3012 GLOBAL_STATE_CODE();
3014 new_child
= g_new(BdrvChild
, 1);
3015 *new_child
= (BdrvChild
) {
3017 .name
= g_strdup(child_name
),
3018 .klass
= child_class
,
3021 .shared_perm
= shared_perm
,
3026 * If the AioContexts don't match, first try to move the subtree of
3027 * child_bs into the AioContext of the new parent. If this doesn't work,
3028 * try moving the parent into the AioContext of child_bs instead.
3030 parent_ctx
= bdrv_child_get_parent_aio_context(new_child
);
3031 if (child_ctx
!= parent_ctx
) {
3032 Error
*local_err
= NULL
;
3033 int ret
= bdrv_try_change_aio_context(child_bs
, parent_ctx
, NULL
,
3036 if (ret
< 0 && child_class
->change_aio_ctx
) {
3037 Transaction
*tran
= tran_new();
3038 GHashTable
*visited
= g_hash_table_new(NULL
, NULL
);
3041 g_hash_table_add(visited
, new_child
);
3042 ret_child
= child_class
->change_aio_ctx(new_child
, child_ctx
,
3043 visited
, tran
, NULL
);
3044 if (ret_child
== true) {
3045 error_free(local_err
);
3048 tran_finalize(tran
, ret_child
== true ? 0 : -1);
3049 g_hash_table_destroy(visited
);
3053 error_propagate(errp
, local_err
);
3054 bdrv_child_free(new_child
);
3059 new_child_ctx
= bdrv_get_aio_context(child_bs
);
3060 if (new_child_ctx
!= child_ctx
) {
3061 aio_context_release(child_ctx
);
3062 aio_context_acquire(new_child_ctx
);
3067 * Let every new BdrvChild start with a drained parent. Inserting the child
3068 * in the graph with bdrv_replace_child_noperm() will undrain it if
3069 * @child_bs is not drained.
3071 * The child was only just created and is not yet visible in global state
3072 * until bdrv_replace_child_noperm() inserts it into the graph, so nobody
3073 * could have sent requests and polling is not necessary.
3075 * Note that this means that the parent isn't fully drained yet, we only
3076 * stop new requests from coming in. This is fine, we don't care about the
3077 * old requests here, they are not for this child. If another place enters a
3078 * drain section for the same parent, but wants it to be fully quiesced, it
3079 * will not run most of the the code in .drained_begin() again (which is not
3080 * a problem, we already did this), but it will still poll until the parent
3081 * is fully quiesced, so it will not be negatively affected either.
3083 bdrv_parent_drained_begin_single(new_child
);
3084 bdrv_replace_child_noperm(new_child
, child_bs
);
3086 BdrvAttachChildCommonState
*s
= g_new(BdrvAttachChildCommonState
, 1);
3087 *s
= (BdrvAttachChildCommonState
) {
3089 .old_parent_ctx
= parent_ctx
,
3090 .old_child_ctx
= child_ctx
,
3092 tran_add(tran
, &bdrv_attach_child_common_drv
, s
);
3094 if (new_child_ctx
!= child_ctx
) {
3095 aio_context_release(new_child_ctx
);
3096 aio_context_acquire(child_ctx
);
3103 * Function doesn't update permissions, caller is responsible for this.
3105 * The caller must hold the AioContext lock for @child_bs. Both @parent_bs and
3106 * @child_bs can move to a different AioContext in this function. Callers must
3107 * make sure that their AioContext locking is still correct after this.
3109 static BdrvChild
*bdrv_attach_child_noperm(BlockDriverState
*parent_bs
,
3110 BlockDriverState
*child_bs
,
3111 const char *child_name
,
3112 const BdrvChildClass
*child_class
,
3113 BdrvChildRole child_role
,
3117 uint64_t perm
, shared_perm
;
3119 assert(parent_bs
->drv
);
3120 GLOBAL_STATE_CODE();
3122 if (bdrv_recurse_has_child(child_bs
, parent_bs
)) {
3123 error_setg(errp
, "Making '%s' a %s child of '%s' would create a cycle",
3124 child_bs
->node_name
, child_name
, parent_bs
->node_name
);
3128 bdrv_get_cumulative_perm(parent_bs
, &perm
, &shared_perm
);
3129 bdrv_child_perm(parent_bs
, child_bs
, NULL
, child_role
, NULL
,
3130 perm
, shared_perm
, &perm
, &shared_perm
);
3132 return bdrv_attach_child_common(child_bs
, child_name
, child_class
,
3133 child_role
, perm
, shared_perm
, parent_bs
,
3138 * This function steals the reference to child_bs from the caller.
3139 * That reference is later dropped by bdrv_root_unref_child().
3141 * On failure NULL is returned, errp is set and the reference to
3142 * child_bs is also dropped.
3144 * The caller must hold the AioContext lock @child_bs, but not that of @ctx
3145 * (unless @child_bs is already in @ctx).
3147 BdrvChild
*bdrv_root_attach_child(BlockDriverState
*child_bs
,
3148 const char *child_name
,
3149 const BdrvChildClass
*child_class
,
3150 BdrvChildRole child_role
,
3151 uint64_t perm
, uint64_t shared_perm
,
3152 void *opaque
, Error
**errp
)
3156 Transaction
*tran
= tran_new();
3158 GLOBAL_STATE_CODE();
3160 child
= bdrv_attach_child_common(child_bs
, child_name
, child_class
,
3161 child_role
, perm
, shared_perm
, opaque
,
3168 ret
= bdrv_refresh_perms(child_bs
, tran
, errp
);
3171 tran_finalize(tran
, ret
);
3173 bdrv_unref(child_bs
);
3175 return ret
< 0 ? NULL
: child
;
3179 * This function transfers the reference to child_bs from the caller
3180 * to parent_bs. That reference is later dropped by parent_bs on
3181 * bdrv_close() or if someone calls bdrv_unref_child().
3183 * On failure NULL is returned, errp is set and the reference to
3184 * child_bs is also dropped.
3186 * If @parent_bs and @child_bs are in different AioContexts, the caller must
3187 * hold the AioContext lock for @child_bs, but not for @parent_bs.
3189 BdrvChild
*bdrv_attach_child(BlockDriverState
*parent_bs
,
3190 BlockDriverState
*child_bs
,
3191 const char *child_name
,
3192 const BdrvChildClass
*child_class
,
3193 BdrvChildRole child_role
,
3198 Transaction
*tran
= tran_new();
3200 GLOBAL_STATE_CODE();
3202 child
= bdrv_attach_child_noperm(parent_bs
, child_bs
, child_name
,
3203 child_class
, child_role
, tran
, errp
);
3209 ret
= bdrv_refresh_perms(parent_bs
, tran
, errp
);
3215 tran_finalize(tran
, ret
);
3217 bdrv_unref(child_bs
);
3219 return ret
< 0 ? NULL
: child
;
3222 /* Callers must ensure that child->frozen is false. */
3223 void bdrv_root_unref_child(BdrvChild
*child
)
3225 BlockDriverState
*child_bs
= child
->bs
;
3227 GLOBAL_STATE_CODE();
3228 bdrv_replace_child_noperm(child
, NULL
);
3229 bdrv_child_free(child
);
3233 * Update permissions for old node. We're just taking a parent away, so
3234 * we're loosening restrictions. Errors of permission update are not
3235 * fatal in this case, ignore them.
3237 bdrv_refresh_perms(child_bs
, NULL
, NULL
);
3240 * When the parent requiring a non-default AioContext is removed, the
3241 * node moves back to the main AioContext
3243 bdrv_try_change_aio_context(child_bs
, qemu_get_aio_context(), NULL
,
3247 bdrv_unref(child_bs
);
3250 typedef struct BdrvSetInheritsFrom
{
3251 BlockDriverState
*bs
;
3252 BlockDriverState
*old_inherits_from
;
3253 } BdrvSetInheritsFrom
;
3255 static void bdrv_set_inherits_from_abort(void *opaque
)
3257 BdrvSetInheritsFrom
*s
= opaque
;
3259 s
->bs
->inherits_from
= s
->old_inherits_from
;
3262 static TransactionActionDrv bdrv_set_inherits_from_drv
= {
3263 .abort
= bdrv_set_inherits_from_abort
,
3267 /* @tran is allowed to be NULL. In this case no rollback is possible */
3268 static void bdrv_set_inherits_from(BlockDriverState
*bs
,
3269 BlockDriverState
*new_inherits_from
,
3273 BdrvSetInheritsFrom
*s
= g_new(BdrvSetInheritsFrom
, 1);
3275 *s
= (BdrvSetInheritsFrom
) {
3277 .old_inherits_from
= bs
->inherits_from
,
3280 tran_add(tran
, &bdrv_set_inherits_from_drv
, s
);
3283 bs
->inherits_from
= new_inherits_from
;
3287 * Clear all inherits_from pointers from children and grandchildren of
3288 * @root that point to @root, where necessary.
3289 * @tran is allowed to be NULL. In this case no rollback is possible
3291 static void bdrv_unset_inherits_from(BlockDriverState
*root
, BdrvChild
*child
,
3296 if (child
->bs
->inherits_from
== root
) {
3298 * Remove inherits_from only when the last reference between root and
3299 * child->bs goes away.
3301 QLIST_FOREACH(c
, &root
->children
, next
) {
3302 if (c
!= child
&& c
->bs
== child
->bs
) {
3307 bdrv_set_inherits_from(child
->bs
, NULL
, tran
);
3311 QLIST_FOREACH(c
, &child
->bs
->children
, next
) {
3312 bdrv_unset_inherits_from(root
, c
, tran
);
3316 /* Callers must ensure that child->frozen is false. */
3317 void bdrv_unref_child(BlockDriverState
*parent
, BdrvChild
*child
)
3319 GLOBAL_STATE_CODE();
3320 if (child
== NULL
) {
3324 bdrv_unset_inherits_from(parent
, child
, NULL
);
3325 bdrv_root_unref_child(child
);
3329 static void bdrv_parent_cb_change_media(BlockDriverState
*bs
, bool load
)
3332 GLOBAL_STATE_CODE();
3333 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
3334 if (c
->klass
->change_media
) {
3335 c
->klass
->change_media(c
, load
);
3340 /* Return true if you can reach parent going through child->inherits_from
3341 * recursively. If parent or child are NULL, return false */
3342 static bool bdrv_inherits_from_recursive(BlockDriverState
*child
,
3343 BlockDriverState
*parent
)
3345 while (child
&& child
!= parent
) {
3346 child
= child
->inherits_from
;
3349 return child
!= NULL
;
3353 * Return the BdrvChildRole for @bs's backing child. bs->backing is
3354 * mostly used for COW backing children (role = COW), but also for
3355 * filtered children (role = FILTERED | PRIMARY).
3357 static BdrvChildRole
bdrv_backing_role(BlockDriverState
*bs
)
3359 if (bs
->drv
&& bs
->drv
->is_filter
) {
3360 return BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
;
3362 return BDRV_CHILD_COW
;
3367 * Sets the bs->backing or bs->file link of a BDS. A new reference is created;
3368 * callers which don't need their own reference any more must call bdrv_unref().
3370 * Function doesn't update permissions, caller is responsible for this.
3372 * The caller must hold the AioContext lock for @child_bs. Both @parent_bs and
3373 * @child_bs can move to a different AioContext in this function. Callers must
3374 * make sure that their AioContext locking is still correct after this.
3376 static int bdrv_set_file_or_backing_noperm(BlockDriverState
*parent_bs
,
3377 BlockDriverState
*child_bs
,
3379 Transaction
*tran
, Error
**errp
)
3381 bool update_inherits_from
=
3382 bdrv_inherits_from_recursive(child_bs
, parent_bs
);
3383 BdrvChild
*child
= is_backing
? parent_bs
->backing
: parent_bs
->file
;
3386 GLOBAL_STATE_CODE();
3388 if (!parent_bs
->drv
) {
3390 * Node without drv is an object without a class :/. TODO: finally fix
3391 * qcow2 driver to never clear bs->drv and implement format corruption
3392 * handling in other way.
3394 error_setg(errp
, "Node corrupted");
3398 if (child
&& child
->frozen
) {
3399 error_setg(errp
, "Cannot change frozen '%s' link from '%s' to '%s'",
3400 child
->name
, parent_bs
->node_name
, child
->bs
->node_name
);
3404 if (is_backing
&& !parent_bs
->drv
->is_filter
&&
3405 !parent_bs
->drv
->supports_backing
)
3407 error_setg(errp
, "Driver '%s' of node '%s' does not support backing "
3408 "files", parent_bs
->drv
->format_name
, parent_bs
->node_name
);
3412 if (parent_bs
->drv
->is_filter
) {
3413 role
= BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
;
3414 } else if (is_backing
) {
3415 role
= BDRV_CHILD_COW
;
3418 * We only can use same role as it is in existing child. We don't have
3419 * infrastructure to determine role of file child in generic way
3422 error_setg(errp
, "Cannot set file child to format node without "
3430 bdrv_unset_inherits_from(parent_bs
, child
, tran
);
3431 bdrv_remove_child(child
, tran
);
3438 child
= bdrv_attach_child_noperm(parent_bs
, child_bs
,
3439 is_backing
? "backing" : "file",
3440 &child_of_bds
, role
,
3448 * If inherits_from pointed recursively to bs then let's update it to
3449 * point directly to bs (else it will become NULL).
3451 if (update_inherits_from
) {
3452 bdrv_set_inherits_from(child_bs
, parent_bs
, tran
);
3456 bdrv_graph_rdlock_main_loop();
3457 bdrv_refresh_limits(parent_bs
, tran
, NULL
);
3458 bdrv_graph_rdunlock_main_loop();
3464 * The caller must hold the AioContext lock for @backing_hd. Both @bs and
3465 * @backing_hd can move to a different AioContext in this function. Callers must
3466 * make sure that their AioContext locking is still correct after this.
3468 static int bdrv_set_backing_noperm(BlockDriverState
*bs
,
3469 BlockDriverState
*backing_hd
,
3470 Transaction
*tran
, Error
**errp
)
3472 GLOBAL_STATE_CODE();
3473 return bdrv_set_file_or_backing_noperm(bs
, backing_hd
, true, tran
, errp
);
3476 int bdrv_set_backing_hd_drained(BlockDriverState
*bs
,
3477 BlockDriverState
*backing_hd
,
3481 Transaction
*tran
= tran_new();
3483 GLOBAL_STATE_CODE();
3484 assert(bs
->quiesce_counter
> 0);
3486 ret
= bdrv_set_backing_noperm(bs
, backing_hd
, tran
, errp
);
3491 ret
= bdrv_refresh_perms(bs
, tran
, errp
);
3493 tran_finalize(tran
, ret
);
3497 int bdrv_set_backing_hd(BlockDriverState
*bs
, BlockDriverState
*backing_hd
,
3501 GLOBAL_STATE_CODE();
3503 bdrv_drained_begin(bs
);
3504 ret
= bdrv_set_backing_hd_drained(bs
, backing_hd
, errp
);
3505 bdrv_drained_end(bs
);
3511 * Opens the backing file for a BlockDriverState if not yet open
3513 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
3514 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
3515 * itself, all options starting with "${bdref_key}." are considered part of the
3518 * The caller must hold the main AioContext lock.
3520 * TODO Can this be unified with bdrv_open_image()?
3522 int bdrv_open_backing_file(BlockDriverState
*bs
, QDict
*parent_options
,
3523 const char *bdref_key
, Error
**errp
)
3525 char *backing_filename
= NULL
;
3526 char *bdref_key_dot
;
3527 const char *reference
= NULL
;
3529 bool implicit_backing
= false;
3530 BlockDriverState
*backing_hd
;
3531 AioContext
*backing_hd_ctx
;
3533 QDict
*tmp_parent_options
= NULL
;
3534 Error
*local_err
= NULL
;
3536 GLOBAL_STATE_CODE();
3538 if (bs
->backing
!= NULL
) {
3542 /* NULL means an empty set of options */
3543 if (parent_options
== NULL
) {
3544 tmp_parent_options
= qdict_new();
3545 parent_options
= tmp_parent_options
;
3548 bs
->open_flags
&= ~BDRV_O_NO_BACKING
;
3550 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
3551 qdict_extract_subqdict(parent_options
, &options
, bdref_key_dot
);
3552 g_free(bdref_key_dot
);
3555 * Caution: while qdict_get_try_str() is fine, getting non-string
3556 * types would require more care. When @parent_options come from
3557 * -blockdev or blockdev_add, its members are typed according to
3558 * the QAPI schema, but when they come from -drive, they're all
3561 reference
= qdict_get_try_str(parent_options
, bdref_key
);
3562 if (reference
|| qdict_haskey(options
, "file.filename")) {
3563 /* keep backing_filename NULL */
3564 } else if (bs
->backing_file
[0] == '\0' && qdict_size(options
) == 0) {
3565 qobject_unref(options
);
3568 if (qdict_size(options
) == 0) {
3569 /* If the user specifies options that do not modify the
3570 * backing file's behavior, we might still consider it the
3571 * implicit backing file. But it's easier this way, and
3572 * just specifying some of the backing BDS's options is
3573 * only possible with -drive anyway (otherwise the QAPI
3574 * schema forces the user to specify everything). */
3575 implicit_backing
= !strcmp(bs
->auto_backing_file
, bs
->backing_file
);
3578 backing_filename
= bdrv_get_full_backing_filename(bs
, &local_err
);
3581 error_propagate(errp
, local_err
);
3582 qobject_unref(options
);
3587 if (!bs
->drv
|| !bs
->drv
->supports_backing
) {
3589 error_setg(errp
, "Driver doesn't support backing files");
3590 qobject_unref(options
);
3595 bs
->backing_format
[0] != '\0' && !qdict_haskey(options
, "driver")) {
3596 qdict_put_str(options
, "driver", bs
->backing_format
);
3599 backing_hd
= bdrv_open_inherit(backing_filename
, reference
, options
, 0, bs
,
3600 &child_of_bds
, bdrv_backing_role(bs
), errp
);
3602 bs
->open_flags
|= BDRV_O_NO_BACKING
;
3603 error_prepend(errp
, "Could not open backing file: ");
3608 if (implicit_backing
) {
3609 bdrv_refresh_filename(backing_hd
);
3610 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
3611 backing_hd
->filename
);
3614 /* Hook up the backing file link; drop our reference, bs owns the
3615 * backing_hd reference now */
3616 backing_hd_ctx
= bdrv_get_aio_context(backing_hd
);
3617 aio_context_acquire(backing_hd_ctx
);
3618 ret
= bdrv_set_backing_hd(bs
, backing_hd
, errp
);
3619 bdrv_unref(backing_hd
);
3620 aio_context_release(backing_hd_ctx
);
3626 qdict_del(parent_options
, bdref_key
);
3629 g_free(backing_filename
);
3630 qobject_unref(tmp_parent_options
);
3634 static BlockDriverState
*
3635 bdrv_open_child_bs(const char *filename
, QDict
*options
, const char *bdref_key
,
3636 BlockDriverState
*parent
, const BdrvChildClass
*child_class
,
3637 BdrvChildRole child_role
, bool allow_none
, Error
**errp
)
3639 BlockDriverState
*bs
= NULL
;
3640 QDict
*image_options
;
3641 char *bdref_key_dot
;
3642 const char *reference
;
3644 assert(child_class
!= NULL
);
3646 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
3647 qdict_extract_subqdict(options
, &image_options
, bdref_key_dot
);
3648 g_free(bdref_key_dot
);
3651 * Caution: while qdict_get_try_str() is fine, getting non-string
3652 * types would require more care. When @options come from
3653 * -blockdev or blockdev_add, its members are typed according to
3654 * the QAPI schema, but when they come from -drive, they're all
3657 reference
= qdict_get_try_str(options
, bdref_key
);
3658 if (!filename
&& !reference
&& !qdict_size(image_options
)) {
3660 error_setg(errp
, "A block device must be specified for \"%s\"",
3663 qobject_unref(image_options
);
3667 bs
= bdrv_open_inherit(filename
, reference
, image_options
, 0,
3668 parent
, child_class
, child_role
, errp
);
3674 qdict_del(options
, bdref_key
);
3679 * Opens a disk image whose options are given as BlockdevRef in another block
3682 * If allow_none is true, no image will be opened if filename is false and no
3683 * BlockdevRef is given. NULL will be returned, but errp remains unset.
3685 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
3686 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
3687 * itself, all options starting with "${bdref_key}." are considered part of the
3690 * The BlockdevRef will be removed from the options QDict.
3692 * The caller must hold the lock of the main AioContext and no other AioContext.
3693 * @parent can move to a different AioContext in this function. Callers must
3694 * make sure that their AioContext locking is still correct after this.
3696 BdrvChild
*bdrv_open_child(const char *filename
,
3697 QDict
*options
, const char *bdref_key
,
3698 BlockDriverState
*parent
,
3699 const BdrvChildClass
*child_class
,
3700 BdrvChildRole child_role
,
3701 bool allow_none
, Error
**errp
)
3703 BlockDriverState
*bs
;
3707 GLOBAL_STATE_CODE();
3709 bs
= bdrv_open_child_bs(filename
, options
, bdref_key
, parent
, child_class
,
3710 child_role
, allow_none
, errp
);
3715 ctx
= bdrv_get_aio_context(bs
);
3716 aio_context_acquire(ctx
);
3717 child
= bdrv_attach_child(parent
, bs
, bdref_key
, child_class
, child_role
,
3719 aio_context_release(ctx
);
3725 * Wrapper on bdrv_open_child() for most popular case: open primary child of bs.
3727 * The caller must hold the lock of the main AioContext and no other AioContext.
3728 * @parent can move to a different AioContext in this function. Callers must
3729 * make sure that their AioContext locking is still correct after this.
3731 int bdrv_open_file_child(const char *filename
,
3732 QDict
*options
, const char *bdref_key
,
3733 BlockDriverState
*parent
, Error
**errp
)
3737 /* commit_top and mirror_top don't use this function */
3738 assert(!parent
->drv
->filtered_child_is_backing
);
3739 role
= parent
->drv
->is_filter
?
3740 (BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
) : BDRV_CHILD_IMAGE
;
3742 if (!bdrv_open_child(filename
, options
, bdref_key
, parent
,
3743 &child_of_bds
, role
, false, errp
))
3752 * TODO Future callers may need to specify parent/child_class in order for
3753 * option inheritance to work. Existing callers use it for the root node.
3755 BlockDriverState
*bdrv_open_blockdev_ref(BlockdevRef
*ref
, Error
**errp
)
3757 BlockDriverState
*bs
= NULL
;
3758 QObject
*obj
= NULL
;
3759 QDict
*qdict
= NULL
;
3760 const char *reference
= NULL
;
3763 GLOBAL_STATE_CODE();
3765 if (ref
->type
== QTYPE_QSTRING
) {
3766 reference
= ref
->u
.reference
;
3768 BlockdevOptions
*options
= &ref
->u
.definition
;
3769 assert(ref
->type
== QTYPE_QDICT
);
3771 v
= qobject_output_visitor_new(&obj
);
3772 visit_type_BlockdevOptions(v
, NULL
, &options
, &error_abort
);
3773 visit_complete(v
, &obj
);
3775 qdict
= qobject_to(QDict
, obj
);
3776 qdict_flatten(qdict
);
3778 /* bdrv_open_inherit() defaults to the values in bdrv_flags (for
3779 * compatibility with other callers) rather than what we want as the
3780 * real defaults. Apply the defaults here instead. */
3781 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_DIRECT
, "off");
3782 qdict_set_default_str(qdict
, BDRV_OPT_CACHE_NO_FLUSH
, "off");
3783 qdict_set_default_str(qdict
, BDRV_OPT_READ_ONLY
, "off");
3784 qdict_set_default_str(qdict
, BDRV_OPT_AUTO_READ_ONLY
, "off");
3788 bs
= bdrv_open_inherit(NULL
, reference
, qdict
, 0, NULL
, NULL
, 0, errp
);
3795 static BlockDriverState
*bdrv_append_temp_snapshot(BlockDriverState
*bs
,
3797 QDict
*snapshot_options
,
3800 g_autofree
char *tmp_filename
= NULL
;
3802 QemuOpts
*opts
= NULL
;
3803 BlockDriverState
*bs_snapshot
= NULL
;
3804 AioContext
*ctx
= bdrv_get_aio_context(bs
);
3807 GLOBAL_STATE_CODE();
3809 /* if snapshot, we create a temporary backing file and open it
3810 instead of opening 'filename' directly */
3812 /* Get the required size from the image */
3813 aio_context_acquire(ctx
);
3814 total_size
= bdrv_getlength(bs
);
3815 aio_context_release(ctx
);
3817 if (total_size
< 0) {
3818 error_setg_errno(errp
, -total_size
, "Could not get image size");
3822 /* Create the temporary image */
3823 tmp_filename
= create_tmp_file(errp
);
3824 if (!tmp_filename
) {
3828 opts
= qemu_opts_create(bdrv_qcow2
.create_opts
, NULL
, 0,
3830 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, total_size
, &error_abort
);
3831 ret
= bdrv_create(&bdrv_qcow2
, tmp_filename
, opts
, errp
);
3832 qemu_opts_del(opts
);
3834 error_prepend(errp
, "Could not create temporary overlay '%s': ",
3839 /* Prepare options QDict for the temporary file */
3840 qdict_put_str(snapshot_options
, "file.driver", "file");
3841 qdict_put_str(snapshot_options
, "file.filename", tmp_filename
);
3842 qdict_put_str(snapshot_options
, "driver", "qcow2");
3844 bs_snapshot
= bdrv_open(NULL
, NULL
, snapshot_options
, flags
, errp
);
3845 snapshot_options
= NULL
;
3850 aio_context_acquire(ctx
);
3851 ret
= bdrv_append(bs_snapshot
, bs
, errp
);
3852 aio_context_release(ctx
);
3860 qobject_unref(snapshot_options
);
3865 * Opens a disk image (raw, qcow2, vmdk, ...)
3867 * options is a QDict of options to pass to the block drivers, or NULL for an
3868 * empty set of options. The reference to the QDict belongs to the block layer
3869 * after the call (even on failure), so if the caller intends to reuse the
3870 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
3872 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
3873 * If it is not NULL, the referenced BDS will be reused.
3875 * The reference parameter may be used to specify an existing block device which
3876 * should be opened. If specified, neither options nor a filename may be given,
3877 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
3879 * The caller must always hold the main AioContext lock.
3881 static BlockDriverState
* no_coroutine_fn
3882 bdrv_open_inherit(const char *filename
, const char *reference
, QDict
*options
,
3883 int flags
, BlockDriverState
*parent
,
3884 const BdrvChildClass
*child_class
, BdrvChildRole child_role
,
3888 BlockBackend
*file
= NULL
;
3889 BlockDriverState
*bs
;
3890 BlockDriver
*drv
= NULL
;
3892 const char *drvname
;
3893 const char *backing
;
3894 Error
*local_err
= NULL
;
3895 QDict
*snapshot_options
= NULL
;
3896 int snapshot_flags
= 0;
3897 AioContext
*ctx
= qemu_get_aio_context();
3899 assert(!child_class
|| !flags
);
3900 assert(!child_class
== !parent
);
3901 GLOBAL_STATE_CODE();
3902 assert(!qemu_in_coroutine());
3905 bool options_non_empty
= options
? qdict_size(options
) : false;
3906 qobject_unref(options
);
3908 if (filename
|| options_non_empty
) {
3909 error_setg(errp
, "Cannot reference an existing block device with "
3910 "additional options or a new filename");
3914 bs
= bdrv_lookup_bs(reference
, reference
, errp
);
3925 /* NULL means an empty set of options */
3926 if (options
== NULL
) {
3927 options
= qdict_new();
3930 /* json: syntax counts as explicit options, as if in the QDict */
3931 parse_json_protocol(options
, &filename
, &local_err
);
3936 bs
->explicit_options
= qdict_clone_shallow(options
);
3939 bool parent_is_format
;
3942 parent_is_format
= parent
->drv
->is_format
;
3945 * parent->drv is not set yet because this node is opened for
3946 * (potential) format probing. That means that @parent is going
3947 * to be a format node.
3949 parent_is_format
= true;
3952 bs
->inherits_from
= parent
;
3953 child_class
->inherit_options(child_role
, parent_is_format
,
3955 parent
->open_flags
, parent
->options
);
3958 ret
= bdrv_fill_options(&options
, filename
, &flags
, &local_err
);
3964 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
3965 * Caution: getting a boolean member of @options requires care.
3966 * When @options come from -blockdev or blockdev_add, members are
3967 * typed according to the QAPI schema, but when they come from
3968 * -drive, they're all QString.
3970 if (g_strcmp0(qdict_get_try_str(options
, BDRV_OPT_READ_ONLY
), "on") &&
3971 !qdict_get_try_bool(options
, BDRV_OPT_READ_ONLY
, false)) {
3972 flags
|= (BDRV_O_RDWR
| BDRV_O_ALLOW_RDWR
);
3974 flags
&= ~BDRV_O_RDWR
;
3977 if (flags
& BDRV_O_SNAPSHOT
) {
3978 snapshot_options
= qdict_new();
3979 bdrv_temp_snapshot_options(&snapshot_flags
, snapshot_options
,
3981 /* Let bdrv_backing_options() override "read-only" */
3982 qdict_del(options
, BDRV_OPT_READ_ONLY
);
3983 bdrv_inherited_options(BDRV_CHILD_COW
, true,
3984 &flags
, options
, flags
, options
);
3987 bs
->open_flags
= flags
;
3988 bs
->options
= options
;
3989 options
= qdict_clone_shallow(options
);
3991 /* Find the right image format driver */
3992 /* See cautionary note on accessing @options above */
3993 drvname
= qdict_get_try_str(options
, "driver");
3995 drv
= bdrv_find_format(drvname
);
3997 error_setg(errp
, "Unknown driver: '%s'", drvname
);
4002 assert(drvname
|| !(flags
& BDRV_O_PROTOCOL
));
4004 /* See cautionary note on accessing @options above */
4005 backing
= qdict_get_try_str(options
, "backing");
4006 if (qobject_to(QNull
, qdict_get(options
, "backing")) != NULL
||
4007 (backing
&& *backing
== '\0'))
4010 warn_report("Use of \"backing\": \"\" is deprecated; "
4011 "use \"backing\": null instead");
4013 flags
|= BDRV_O_NO_BACKING
;
4014 qdict_del(bs
->explicit_options
, "backing");
4015 qdict_del(bs
->options
, "backing");
4016 qdict_del(options
, "backing");
4019 /* Open image file without format layer. This BlockBackend is only used for
4020 * probing, the block drivers will do their own bdrv_open_child() for the
4021 * same BDS, which is why we put the node name back into options. */
4022 if ((flags
& BDRV_O_PROTOCOL
) == 0) {
4023 BlockDriverState
*file_bs
;
4025 file_bs
= bdrv_open_child_bs(filename
, options
, "file", bs
,
4026 &child_of_bds
, BDRV_CHILD_IMAGE
,
4031 if (file_bs
!= NULL
) {
4032 /* Not requesting BLK_PERM_CONSISTENT_READ because we're only
4033 * looking at the header to guess the image format. This works even
4034 * in cases where a guest would not see a consistent state. */
4035 ctx
= bdrv_get_aio_context(file_bs
);
4036 aio_context_acquire(ctx
);
4037 file
= blk_new(ctx
, 0, BLK_PERM_ALL
);
4038 blk_insert_bs(file
, file_bs
, &local_err
);
4039 bdrv_unref(file_bs
);
4040 aio_context_release(ctx
);
4046 qdict_put_str(options
, "file", bdrv_get_node_name(file_bs
));
4050 /* Image format probing */
4053 ret
= find_image_format(file
, filename
, &drv
, &local_err
);
4058 * This option update would logically belong in bdrv_fill_options(),
4059 * but we first need to open bs->file for the probing to work, while
4060 * opening bs->file already requires the (mostly) final set of options
4061 * so that cache mode etc. can be inherited.
4063 * Adding the driver later is somewhat ugly, but it's not an option
4064 * that would ever be inherited, so it's correct. We just need to make
4065 * sure to update both bs->options (which has the full effective
4066 * options for bs) and options (which has file.* already removed).
4068 qdict_put_str(bs
->options
, "driver", drv
->format_name
);
4069 qdict_put_str(options
, "driver", drv
->format_name
);
4071 error_setg(errp
, "Must specify either driver or file");
4075 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
4076 assert(!!(flags
& BDRV_O_PROTOCOL
) == !!drv
->bdrv_file_open
);
4077 /* file must be NULL if a protocol BDS is about to be created
4078 * (the inverse results in an error message from bdrv_open_common()) */
4079 assert(!(flags
& BDRV_O_PROTOCOL
) || !file
);
4081 /* Open the image */
4082 ret
= bdrv_open_common(bs
, file
, options
, &local_err
);
4087 /* The AioContext could have changed during bdrv_open_common() */
4088 ctx
= bdrv_get_aio_context(bs
);
4091 aio_context_acquire(ctx
);
4093 aio_context_release(ctx
);
4097 /* If there is a backing file, use it */
4098 if ((flags
& BDRV_O_NO_BACKING
) == 0) {
4099 ret
= bdrv_open_backing_file(bs
, options
, "backing", &local_err
);
4101 goto close_and_fail
;
4105 /* Remove all children options and references
4106 * from bs->options and bs->explicit_options */
4107 QLIST_FOREACH(child
, &bs
->children
, next
) {
4108 char *child_key_dot
;
4109 child_key_dot
= g_strdup_printf("%s.", child
->name
);
4110 qdict_extract_subqdict(bs
->explicit_options
, NULL
, child_key_dot
);
4111 qdict_extract_subqdict(bs
->options
, NULL
, child_key_dot
);
4112 qdict_del(bs
->explicit_options
, child
->name
);
4113 qdict_del(bs
->options
, child
->name
);
4114 g_free(child_key_dot
);
4117 /* Check if any unknown options were used */
4118 if (qdict_size(options
) != 0) {
4119 const QDictEntry
*entry
= qdict_first(options
);
4120 if (flags
& BDRV_O_PROTOCOL
) {
4121 error_setg(errp
, "Block protocol '%s' doesn't support the option "
4122 "'%s'", drv
->format_name
, entry
->key
);
4125 "Block format '%s' does not support the option '%s'",
4126 drv
->format_name
, entry
->key
);
4129 goto close_and_fail
;
4132 bdrv_parent_cb_change_media(bs
, true);
4134 qobject_unref(options
);
4137 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
4138 * temporary snapshot afterwards. */
4139 if (snapshot_flags
) {
4140 BlockDriverState
*snapshot_bs
;
4141 snapshot_bs
= bdrv_append_temp_snapshot(bs
, snapshot_flags
,
4142 snapshot_options
, &local_err
);
4143 snapshot_options
= NULL
;
4145 goto close_and_fail
;
4147 /* We are not going to return bs but the overlay on top of it
4148 * (snapshot_bs); thus, we have to drop the strong reference to bs
4149 * (which we obtained by calling bdrv_new()). bs will not be deleted,
4150 * though, because the overlay still has a reference to it. */
4151 aio_context_acquire(ctx
);
4153 aio_context_release(ctx
);
4160 aio_context_acquire(ctx
);
4162 qobject_unref(snapshot_options
);
4163 qobject_unref(bs
->explicit_options
);
4164 qobject_unref(bs
->options
);
4165 qobject_unref(options
);
4167 bs
->explicit_options
= NULL
;
4169 aio_context_release(ctx
);
4170 error_propagate(errp
, local_err
);
4174 aio_context_acquire(ctx
);
4176 aio_context_release(ctx
);
4177 qobject_unref(snapshot_options
);
4178 qobject_unref(options
);
4179 error_propagate(errp
, local_err
);
4183 /* The caller must always hold the main AioContext lock. */
4184 BlockDriverState
*bdrv_open(const char *filename
, const char *reference
,
4185 QDict
*options
, int flags
, Error
**errp
)
4187 GLOBAL_STATE_CODE();
4189 return bdrv_open_inherit(filename
, reference
, options
, flags
, NULL
,
4193 /* Return true if the NULL-terminated @list contains @str */
4194 static bool is_str_in_list(const char *str
, const char *const *list
)
4198 for (i
= 0; list
[i
] != NULL
; i
++) {
4199 if (!strcmp(str
, list
[i
])) {
4208 * Check that every option set in @bs->options is also set in
4211 * Options listed in the common_options list and in
4212 * @bs->drv->mutable_opts are skipped.
4214 * Return 0 on success, otherwise return -EINVAL and set @errp.
4216 static int bdrv_reset_options_allowed(BlockDriverState
*bs
,
4217 const QDict
*new_opts
, Error
**errp
)
4219 const QDictEntry
*e
;
4220 /* These options are common to all block drivers and are handled
4221 * in bdrv_reopen_prepare() so they can be left out of @new_opts */
4222 const char *const common_options
[] = {
4223 "node-name", "discard", "cache.direct", "cache.no-flush",
4224 "read-only", "auto-read-only", "detect-zeroes", NULL
4227 for (e
= qdict_first(bs
->options
); e
; e
= qdict_next(bs
->options
, e
)) {
4228 if (!qdict_haskey(new_opts
, e
->key
) &&
4229 !is_str_in_list(e
->key
, common_options
) &&
4230 !is_str_in_list(e
->key
, bs
->drv
->mutable_opts
)) {
4231 error_setg(errp
, "Option '%s' cannot be reset "
4232 "to its default value", e
->key
);
4241 * Returns true if @child can be reached recursively from @bs
4243 static bool bdrv_recurse_has_child(BlockDriverState
*bs
,
4244 BlockDriverState
*child
)
4252 QLIST_FOREACH(c
, &bs
->children
, next
) {
4253 if (bdrv_recurse_has_child(c
->bs
, child
)) {
4262 * Adds a BlockDriverState to a simple queue for an atomic, transactional
4263 * reopen of multiple devices.
4265 * bs_queue can either be an existing BlockReopenQueue that has had QTAILQ_INIT
4266 * already performed, or alternatively may be NULL a new BlockReopenQueue will
4267 * be created and initialized. This newly created BlockReopenQueue should be
4268 * passed back in for subsequent calls that are intended to be of the same
4271 * bs is the BlockDriverState to add to the reopen queue.
4273 * options contains the changed options for the associated bs
4274 * (the BlockReopenQueue takes ownership)
4276 * flags contains the open flags for the associated bs
4278 * returns a pointer to bs_queue, which is either the newly allocated
4279 * bs_queue, or the existing bs_queue being used.
4281 * bs is drained here and undrained by bdrv_reopen_queue_free().
4283 * To be called with bs->aio_context locked.
4285 static BlockReopenQueue
*bdrv_reopen_queue_child(BlockReopenQueue
*bs_queue
,
4286 BlockDriverState
*bs
,
4288 const BdrvChildClass
*klass
,
4290 bool parent_is_format
,
4291 QDict
*parent_options
,
4297 BlockReopenQueueEntry
*bs_entry
;
4299 QDict
*old_options
, *explicit_options
, *options_copy
;
4303 GLOBAL_STATE_CODE();
4305 bdrv_drained_begin(bs
);
4307 if (bs_queue
== NULL
) {
4308 bs_queue
= g_new0(BlockReopenQueue
, 1);
4309 QTAILQ_INIT(bs_queue
);
4313 options
= qdict_new();
4316 /* Check if this BlockDriverState is already in the queue */
4317 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4318 if (bs
== bs_entry
->state
.bs
) {
4324 * Precedence of options:
4325 * 1. Explicitly passed in options (highest)
4326 * 2. Retained from explicitly set options of bs
4327 * 3. Inherited from parent node
4328 * 4. Retained from effective options of bs
4331 /* Old explicitly set values (don't overwrite by inherited value) */
4332 if (bs_entry
|| keep_old_opts
) {
4333 old_options
= qdict_clone_shallow(bs_entry
?
4334 bs_entry
->state
.explicit_options
:
4335 bs
->explicit_options
);
4336 bdrv_join_options(bs
, options
, old_options
);
4337 qobject_unref(old_options
);
4340 explicit_options
= qdict_clone_shallow(options
);
4342 /* Inherit from parent node */
4343 if (parent_options
) {
4345 klass
->inherit_options(role
, parent_is_format
, &flags
, options
,
4346 parent_flags
, parent_options
);
4348 flags
= bdrv_get_flags(bs
);
4351 if (keep_old_opts
) {
4352 /* Old values are used for options that aren't set yet */
4353 old_options
= qdict_clone_shallow(bs
->options
);
4354 bdrv_join_options(bs
, options
, old_options
);
4355 qobject_unref(old_options
);
4358 /* We have the final set of options so let's update the flags */
4359 options_copy
= qdict_clone_shallow(options
);
4360 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
4361 qemu_opts_absorb_qdict(opts
, options_copy
, NULL
);
4362 update_flags_from_options(&flags
, opts
);
4363 qemu_opts_del(opts
);
4364 qobject_unref(options_copy
);
4366 /* bdrv_open_inherit() sets and clears some additional flags internally */
4367 flags
&= ~BDRV_O_PROTOCOL
;
4368 if (flags
& BDRV_O_RDWR
) {
4369 flags
|= BDRV_O_ALLOW_RDWR
;
4373 bs_entry
= g_new0(BlockReopenQueueEntry
, 1);
4374 QTAILQ_INSERT_TAIL(bs_queue
, bs_entry
, entry
);
4376 qobject_unref(bs_entry
->state
.options
);
4377 qobject_unref(bs_entry
->state
.explicit_options
);
4380 bs_entry
->state
.bs
= bs
;
4381 bs_entry
->state
.options
= options
;
4382 bs_entry
->state
.explicit_options
= explicit_options
;
4383 bs_entry
->state
.flags
= flags
;
4386 * If keep_old_opts is false then it means that unspecified
4387 * options must be reset to their original value. We don't allow
4388 * resetting 'backing' but we need to know if the option is
4389 * missing in order to decide if we have to return an error.
4391 if (!keep_old_opts
) {
4392 bs_entry
->state
.backing_missing
=
4393 !qdict_haskey(options
, "backing") &&
4394 !qdict_haskey(options
, "backing.driver");
4397 QLIST_FOREACH(child
, &bs
->children
, next
) {
4398 QDict
*new_child_options
= NULL
;
4399 bool child_keep_old
= keep_old_opts
;
4401 /* reopen can only change the options of block devices that were
4402 * implicitly created and inherited options. For other (referenced)
4403 * block devices, a syntax like "backing.foo" results in an error. */
4404 if (child
->bs
->inherits_from
!= bs
) {
4408 /* Check if the options contain a child reference */
4409 if (qdict_haskey(options
, child
->name
)) {
4410 const char *childref
= qdict_get_try_str(options
, child
->name
);
4412 * The current child must not be reopened if the child
4413 * reference is null or points to a different node.
4415 if (g_strcmp0(childref
, child
->bs
->node_name
)) {
4419 * If the child reference points to the current child then
4420 * reopen it with its existing set of options (note that
4421 * it can still inherit new options from the parent).
4423 child_keep_old
= true;
4425 /* Extract child options ("child-name.*") */
4426 char *child_key_dot
= g_strdup_printf("%s.", child
->name
);
4427 qdict_extract_subqdict(explicit_options
, NULL
, child_key_dot
);
4428 qdict_extract_subqdict(options
, &new_child_options
, child_key_dot
);
4429 g_free(child_key_dot
);
4432 bdrv_reopen_queue_child(bs_queue
, child
->bs
, new_child_options
,
4433 child
->klass
, child
->role
, bs
->drv
->is_format
,
4434 options
, flags
, child_keep_old
);
4440 /* To be called with bs->aio_context locked */
4441 BlockReopenQueue
*bdrv_reopen_queue(BlockReopenQueue
*bs_queue
,
4442 BlockDriverState
*bs
,
4443 QDict
*options
, bool keep_old_opts
)
4445 GLOBAL_STATE_CODE();
4447 return bdrv_reopen_queue_child(bs_queue
, bs
, options
, NULL
, 0, false,
4448 NULL
, 0, keep_old_opts
);
4451 void bdrv_reopen_queue_free(BlockReopenQueue
*bs_queue
)
4453 GLOBAL_STATE_CODE();
4455 BlockReopenQueueEntry
*bs_entry
, *next
;
4456 QTAILQ_FOREACH_SAFE(bs_entry
, bs_queue
, entry
, next
) {
4457 AioContext
*ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4459 aio_context_acquire(ctx
);
4460 bdrv_drained_end(bs_entry
->state
.bs
);
4461 aio_context_release(ctx
);
4463 qobject_unref(bs_entry
->state
.explicit_options
);
4464 qobject_unref(bs_entry
->state
.options
);
4472 * Reopen multiple BlockDriverStates atomically & transactionally.
4474 * The queue passed in (bs_queue) must have been built up previous
4475 * via bdrv_reopen_queue().
4477 * Reopens all BDS specified in the queue, with the appropriate
4478 * flags. All devices are prepared for reopen, and failure of any
4479 * device will cause all device changes to be abandoned, and intermediate
4482 * If all devices prepare successfully, then the changes are committed
4485 * All affected nodes must be drained between bdrv_reopen_queue() and
4486 * bdrv_reopen_multiple().
4488 * To be called from the main thread, with all other AioContexts unlocked.
4490 int bdrv_reopen_multiple(BlockReopenQueue
*bs_queue
, Error
**errp
)
4493 BlockReopenQueueEntry
*bs_entry
, *next
;
4495 Transaction
*tran
= tran_new();
4496 g_autoptr(GSList
) refresh_list
= NULL
;
4498 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
4499 assert(bs_queue
!= NULL
);
4500 GLOBAL_STATE_CODE();
4502 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4503 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4504 aio_context_acquire(ctx
);
4505 ret
= bdrv_flush(bs_entry
->state
.bs
);
4506 aio_context_release(ctx
);
4508 error_setg_errno(errp
, -ret
, "Error flushing drive");
4513 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4514 assert(bs_entry
->state
.bs
->quiesce_counter
> 0);
4515 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4516 aio_context_acquire(ctx
);
4517 ret
= bdrv_reopen_prepare(&bs_entry
->state
, bs_queue
, tran
, errp
);
4518 aio_context_release(ctx
);
4522 bs_entry
->prepared
= true;
4525 QTAILQ_FOREACH(bs_entry
, bs_queue
, entry
) {
4526 BDRVReopenState
*state
= &bs_entry
->state
;
4528 refresh_list
= g_slist_prepend(refresh_list
, state
->bs
);
4529 if (state
->old_backing_bs
) {
4530 refresh_list
= g_slist_prepend(refresh_list
, state
->old_backing_bs
);
4532 if (state
->old_file_bs
) {
4533 refresh_list
= g_slist_prepend(refresh_list
, state
->old_file_bs
);
4538 * Note that file-posix driver rely on permission update done during reopen
4539 * (even if no permission changed), because it wants "new" permissions for
4540 * reconfiguring the fd and that's why it does it in raw_check_perm(), not
4541 * in raw_reopen_prepare() which is called with "old" permissions.
4543 ret
= bdrv_list_refresh_perms(refresh_list
, bs_queue
, tran
, errp
);
4549 * If we reach this point, we have success and just need to apply the
4552 * Reverse order is used to comfort qcow2 driver: on commit it need to write
4553 * IN_USE flag to the image, to mark bitmaps in the image as invalid. But
4554 * children are usually goes after parents in reopen-queue, so go from last
4557 QTAILQ_FOREACH_REVERSE(bs_entry
, bs_queue
, entry
) {
4558 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4559 aio_context_acquire(ctx
);
4560 bdrv_reopen_commit(&bs_entry
->state
);
4561 aio_context_release(ctx
);
4566 QTAILQ_FOREACH_REVERSE(bs_entry
, bs_queue
, entry
) {
4567 BlockDriverState
*bs
= bs_entry
->state
.bs
;
4569 if (bs
->drv
->bdrv_reopen_commit_post
) {
4570 ctx
= bdrv_get_aio_context(bs
);
4571 aio_context_acquire(ctx
);
4572 bs
->drv
->bdrv_reopen_commit_post(&bs_entry
->state
);
4573 aio_context_release(ctx
);
4582 QTAILQ_FOREACH_SAFE(bs_entry
, bs_queue
, entry
, next
) {
4583 if (bs_entry
->prepared
) {
4584 ctx
= bdrv_get_aio_context(bs_entry
->state
.bs
);
4585 aio_context_acquire(ctx
);
4586 bdrv_reopen_abort(&bs_entry
->state
);
4587 aio_context_release(ctx
);
4592 bdrv_reopen_queue_free(bs_queue
);
4597 int bdrv_reopen(BlockDriverState
*bs
, QDict
*opts
, bool keep_old_opts
,
4600 AioContext
*ctx
= bdrv_get_aio_context(bs
);
4601 BlockReopenQueue
*queue
;
4604 GLOBAL_STATE_CODE();
4606 queue
= bdrv_reopen_queue(NULL
, bs
, opts
, keep_old_opts
);
4608 if (ctx
!= qemu_get_aio_context()) {
4609 aio_context_release(ctx
);
4611 ret
= bdrv_reopen_multiple(queue
, errp
);
4613 if (ctx
!= qemu_get_aio_context()) {
4614 aio_context_acquire(ctx
);
4620 int bdrv_reopen_set_read_only(BlockDriverState
*bs
, bool read_only
,
4623 QDict
*opts
= qdict_new();
4625 GLOBAL_STATE_CODE();
4627 qdict_put_bool(opts
, BDRV_OPT_READ_ONLY
, read_only
);
4629 return bdrv_reopen(bs
, opts
, true, errp
);
4633 * Take a BDRVReopenState and check if the value of 'backing' in the
4634 * reopen_state->options QDict is valid or not.
4636 * If 'backing' is missing from the QDict then return 0.
4638 * If 'backing' contains the node name of the backing file of
4639 * reopen_state->bs then return 0.
4641 * If 'backing' contains a different node name (or is null) then check
4642 * whether the current backing file can be replaced with the new one.
4643 * If that's the case then reopen_state->replace_backing_bs is set to
4644 * true and reopen_state->new_backing_bs contains a pointer to the new
4645 * backing BlockDriverState (or NULL).
4647 * Return 0 on success, otherwise return < 0 and set @errp.
4649 * The caller must hold the AioContext lock of @reopen_state->bs.
4650 * @reopen_state->bs can move to a different AioContext in this function.
4651 * Callers must make sure that their AioContext locking is still correct after
4654 static int bdrv_reopen_parse_file_or_backing(BDRVReopenState
*reopen_state
,
4655 bool is_backing
, Transaction
*tran
,
4658 BlockDriverState
*bs
= reopen_state
->bs
;
4659 BlockDriverState
*new_child_bs
;
4660 BlockDriverState
*old_child_bs
= is_backing
? child_bs(bs
->backing
) :
4662 const char *child_name
= is_backing
? "backing" : "file";
4665 AioContext
*ctx
, *old_ctx
;
4668 GLOBAL_STATE_CODE();
4670 value
= qdict_get(reopen_state
->options
, child_name
);
4671 if (value
== NULL
) {
4675 switch (qobject_type(value
)) {
4677 assert(is_backing
); /* The 'file' option does not allow a null value */
4678 new_child_bs
= NULL
;
4681 str
= qstring_get_str(qobject_to(QString
, value
));
4682 new_child_bs
= bdrv_lookup_bs(NULL
, str
, errp
);
4683 if (new_child_bs
== NULL
) {
4685 } else if (bdrv_recurse_has_child(new_child_bs
, bs
)) {
4686 error_setg(errp
, "Making '%s' a %s child of '%s' would create a "
4687 "cycle", str
, child_name
, bs
->node_name
);
4693 * The options QDict has been flattened, so 'backing' and 'file'
4694 * do not allow any other data type here.
4696 g_assert_not_reached();
4699 if (old_child_bs
== new_child_bs
) {
4704 if (bdrv_skip_implicit_filters(old_child_bs
) == new_child_bs
) {
4708 if (old_child_bs
->implicit
) {
4709 error_setg(errp
, "Cannot replace implicit %s child of %s",
4710 child_name
, bs
->node_name
);
4715 if (bs
->drv
->is_filter
&& !old_child_bs
) {
4717 * Filters always have a file or a backing child, so we are trying to
4718 * change wrong child
4720 error_setg(errp
, "'%s' is a %s filter node that does not support a "
4721 "%s child", bs
->node_name
, bs
->drv
->format_name
, child_name
);
4726 reopen_state
->old_backing_bs
= old_child_bs
;
4728 reopen_state
->old_file_bs
= old_child_bs
;
4731 old_ctx
= bdrv_get_aio_context(bs
);
4732 ctx
= bdrv_get_aio_context(new_child_bs
);
4733 if (old_ctx
!= ctx
) {
4734 aio_context_release(old_ctx
);
4735 aio_context_acquire(ctx
);
4738 ret
= bdrv_set_file_or_backing_noperm(bs
, new_child_bs
, is_backing
,
4741 if (old_ctx
!= ctx
) {
4742 aio_context_release(ctx
);
4743 aio_context_acquire(old_ctx
);
4750 * Prepares a BlockDriverState for reopen. All changes are staged in the
4751 * 'opaque' field of the BDRVReopenState, which is used and allocated by
4752 * the block driver layer .bdrv_reopen_prepare()
4754 * bs is the BlockDriverState to reopen
4755 * flags are the new open flags
4756 * queue is the reopen queue
4758 * Returns 0 on success, non-zero on error. On error errp will be set
4761 * On failure, bdrv_reopen_abort() will be called to clean up any data.
4762 * It is the responsibility of the caller to then call the abort() or
4763 * commit() for any other BDS that have been left in a prepare() state
4765 * The caller must hold the AioContext lock of @reopen_state->bs.
4767 static int bdrv_reopen_prepare(BDRVReopenState
*reopen_state
,
4768 BlockReopenQueue
*queue
,
4769 Transaction
*change_child_tran
, Error
**errp
)
4773 Error
*local_err
= NULL
;
4776 QDict
*orig_reopen_opts
;
4777 char *discard
= NULL
;
4779 bool drv_prepared
= false;
4781 assert(reopen_state
!= NULL
);
4782 assert(reopen_state
->bs
->drv
!= NULL
);
4783 GLOBAL_STATE_CODE();
4784 drv
= reopen_state
->bs
->drv
;
4786 /* This function and each driver's bdrv_reopen_prepare() remove
4787 * entries from reopen_state->options as they are processed, so
4788 * we need to make a copy of the original QDict. */
4789 orig_reopen_opts
= qdict_clone_shallow(reopen_state
->options
);
4791 /* Process generic block layer options */
4792 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
4793 if (!qemu_opts_absorb_qdict(opts
, reopen_state
->options
, errp
)) {
4798 /* This was already called in bdrv_reopen_queue_child() so the flags
4799 * are up-to-date. This time we simply want to remove the options from
4800 * QemuOpts in order to indicate that they have been processed. */
4801 old_flags
= reopen_state
->flags
;
4802 update_flags_from_options(&reopen_state
->flags
, opts
);
4803 assert(old_flags
== reopen_state
->flags
);
4805 discard
= qemu_opt_get_del(opts
, BDRV_OPT_DISCARD
);
4806 if (discard
!= NULL
) {
4807 if (bdrv_parse_discard_flags(discard
, &reopen_state
->flags
) != 0) {
4808 error_setg(errp
, "Invalid discard option");
4814 reopen_state
->detect_zeroes
=
4815 bdrv_parse_detect_zeroes(opts
, reopen_state
->flags
, &local_err
);
4817 error_propagate(errp
, local_err
);
4822 /* All other options (including node-name and driver) must be unchanged.
4823 * Put them back into the QDict, so that they are checked at the end
4824 * of this function. */
4825 qemu_opts_to_qdict(opts
, reopen_state
->options
);
4827 /* If we are to stay read-only, do not allow permission change
4828 * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is
4829 * not set, or if the BDS still has copy_on_read enabled */
4830 read_only
= !(reopen_state
->flags
& BDRV_O_RDWR
);
4831 ret
= bdrv_can_set_read_only(reopen_state
->bs
, read_only
, true, &local_err
);
4833 error_propagate(errp
, local_err
);
4837 if (drv
->bdrv_reopen_prepare
) {
4839 * If a driver-specific option is missing, it means that we
4840 * should reset it to its default value.
4841 * But not all options allow that, so we need to check it first.
4843 ret
= bdrv_reset_options_allowed(reopen_state
->bs
,
4844 reopen_state
->options
, errp
);
4849 ret
= drv
->bdrv_reopen_prepare(reopen_state
, queue
, &local_err
);
4851 if (local_err
!= NULL
) {
4852 error_propagate(errp
, local_err
);
4854 bdrv_refresh_filename(reopen_state
->bs
);
4855 error_setg(errp
, "failed while preparing to reopen image '%s'",
4856 reopen_state
->bs
->filename
);
4861 /* It is currently mandatory to have a bdrv_reopen_prepare()
4862 * handler for each supported drv. */
4863 error_setg(errp
, "Block format '%s' used by node '%s' "
4864 "does not support reopening files", drv
->format_name
,
4865 bdrv_get_device_or_node_name(reopen_state
->bs
));
4870 drv_prepared
= true;
4873 * We must provide the 'backing' option if the BDS has a backing
4874 * file or if the image file has a backing file name as part of
4875 * its metadata. Otherwise the 'backing' option can be omitted.
4877 if (drv
->supports_backing
&& reopen_state
->backing_missing
&&
4878 (reopen_state
->bs
->backing
|| reopen_state
->bs
->backing_file
[0])) {
4879 error_setg(errp
, "backing is missing for '%s'",
4880 reopen_state
->bs
->node_name
);
4886 * Allow changing the 'backing' option. The new value can be
4887 * either a reference to an existing node (using its node name)
4888 * or NULL to simply detach the current backing file.
4890 ret
= bdrv_reopen_parse_file_or_backing(reopen_state
, true,
4891 change_child_tran
, errp
);
4895 qdict_del(reopen_state
->options
, "backing");
4897 /* Allow changing the 'file' option. In this case NULL is not allowed */
4898 ret
= bdrv_reopen_parse_file_or_backing(reopen_state
, false,
4899 change_child_tran
, errp
);
4903 qdict_del(reopen_state
->options
, "file");
4905 /* Options that are not handled are only okay if they are unchanged
4906 * compared to the old state. It is expected that some options are only
4907 * used for the initial open, but not reopen (e.g. filename) */
4908 if (qdict_size(reopen_state
->options
)) {
4909 const QDictEntry
*entry
= qdict_first(reopen_state
->options
);
4912 QObject
*new = entry
->value
;
4913 QObject
*old
= qdict_get(reopen_state
->bs
->options
, entry
->key
);
4915 /* Allow child references (child_name=node_name) as long as they
4916 * point to the current child (i.e. everything stays the same). */
4917 if (qobject_type(new) == QTYPE_QSTRING
) {
4919 QLIST_FOREACH(child
, &reopen_state
->bs
->children
, next
) {
4920 if (!strcmp(child
->name
, entry
->key
)) {
4926 if (!strcmp(child
->bs
->node_name
,
4927 qstring_get_str(qobject_to(QString
, new)))) {
4928 continue; /* Found child with this name, skip option */
4934 * TODO: When using -drive to specify blockdev options, all values
4935 * will be strings; however, when using -blockdev, blockdev-add or
4936 * filenames using the json:{} pseudo-protocol, they will be
4938 * In contrast, reopening options are (currently) always strings
4939 * (because you can only specify them through qemu-io; all other
4940 * callers do not specify any options).
4941 * Therefore, when using anything other than -drive to create a BDS,
4942 * this cannot detect non-string options as unchanged, because
4943 * qobject_is_equal() always returns false for objects of different
4944 * type. In the future, this should be remedied by correctly typing
4945 * all options. For now, this is not too big of an issue because
4946 * the user can simply omit options which cannot be changed anyway,
4947 * so they will stay unchanged.
4949 if (!qobject_is_equal(new, old
)) {
4950 error_setg(errp
, "Cannot change the option '%s'", entry
->key
);
4954 } while ((entry
= qdict_next(reopen_state
->options
, entry
)));
4959 /* Restore the original reopen_state->options QDict */
4960 qobject_unref(reopen_state
->options
);
4961 reopen_state
->options
= qobject_ref(orig_reopen_opts
);
4964 if (ret
< 0 && drv_prepared
) {
4965 /* drv->bdrv_reopen_prepare() has succeeded, so we need to
4966 * call drv->bdrv_reopen_abort() before signaling an error
4967 * (bdrv_reopen_multiple() will not call bdrv_reopen_abort()
4968 * when the respective bdrv_reopen_prepare() has failed) */
4969 if (drv
->bdrv_reopen_abort
) {
4970 drv
->bdrv_reopen_abort(reopen_state
);
4973 qemu_opts_del(opts
);
4974 qobject_unref(orig_reopen_opts
);
4980 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
4981 * makes them final by swapping the staging BlockDriverState contents into
4982 * the active BlockDriverState contents.
4984 static void bdrv_reopen_commit(BDRVReopenState
*reopen_state
)
4987 BlockDriverState
*bs
;
4990 assert(reopen_state
!= NULL
);
4991 bs
= reopen_state
->bs
;
4993 assert(drv
!= NULL
);
4994 GLOBAL_STATE_CODE();
4996 /* If there are any driver level actions to take */
4997 if (drv
->bdrv_reopen_commit
) {
4998 drv
->bdrv_reopen_commit(reopen_state
);
5001 /* set BDS specific flags now */
5002 qobject_unref(bs
->explicit_options
);
5003 qobject_unref(bs
->options
);
5004 qobject_ref(reopen_state
->explicit_options
);
5005 qobject_ref(reopen_state
->options
);
5007 bs
->explicit_options
= reopen_state
->explicit_options
;
5008 bs
->options
= reopen_state
->options
;
5009 bs
->open_flags
= reopen_state
->flags
;
5010 bs
->detect_zeroes
= reopen_state
->detect_zeroes
;
5012 /* Remove child references from bs->options and bs->explicit_options.
5013 * Child options were already removed in bdrv_reopen_queue_child() */
5014 QLIST_FOREACH(child
, &bs
->children
, next
) {
5015 qdict_del(bs
->explicit_options
, child
->name
);
5016 qdict_del(bs
->options
, child
->name
);
5018 /* backing is probably removed, so it's not handled by previous loop */
5019 qdict_del(bs
->explicit_options
, "backing");
5020 qdict_del(bs
->options
, "backing");
5022 bdrv_graph_rdlock_main_loop();
5023 bdrv_refresh_limits(bs
, NULL
, NULL
);
5024 bdrv_graph_rdunlock_main_loop();
5025 bdrv_refresh_total_sectors(bs
, bs
->total_sectors
);
5029 * Abort the reopen, and delete and free the staged changes in
5032 static void bdrv_reopen_abort(BDRVReopenState
*reopen_state
)
5036 assert(reopen_state
!= NULL
);
5037 drv
= reopen_state
->bs
->drv
;
5038 assert(drv
!= NULL
);
5039 GLOBAL_STATE_CODE();
5041 if (drv
->bdrv_reopen_abort
) {
5042 drv
->bdrv_reopen_abort(reopen_state
);
5047 static void bdrv_close(BlockDriverState
*bs
)
5049 BdrvAioNotifier
*ban
, *ban_next
;
5050 BdrvChild
*child
, *next
;
5052 GLOBAL_STATE_CODE();
5053 assert(!bs
->refcnt
);
5055 bdrv_drained_begin(bs
); /* complete I/O */
5057 bdrv_drain(bs
); /* in case flush left pending I/O */
5060 if (bs
->drv
->bdrv_close
) {
5061 /* Must unfreeze all children, so bdrv_unref_child() works */
5062 bs
->drv
->bdrv_close(bs
);
5067 QLIST_FOREACH_SAFE(child
, &bs
->children
, next
, next
) {
5068 bdrv_unref_child(bs
, child
);
5071 assert(!bs
->backing
);
5075 qatomic_set(&bs
->copy_on_read
, 0);
5076 bs
->backing_file
[0] = '\0';
5077 bs
->backing_format
[0] = '\0';
5078 bs
->total_sectors
= 0;
5079 bs
->encrypted
= false;
5081 qobject_unref(bs
->options
);
5082 qobject_unref(bs
->explicit_options
);
5084 bs
->explicit_options
= NULL
;
5085 qobject_unref(bs
->full_open_options
);
5086 bs
->full_open_options
= NULL
;
5087 g_free(bs
->block_status_cache
);
5088 bs
->block_status_cache
= NULL
;
5090 bdrv_release_named_dirty_bitmaps(bs
);
5091 assert(QLIST_EMPTY(&bs
->dirty_bitmaps
));
5093 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_next
) {
5096 QLIST_INIT(&bs
->aio_notifiers
);
5097 bdrv_drained_end(bs
);
5100 * If we're still inside some bdrv_drain_all_begin()/end() sections, end
5101 * them now since this BDS won't exist anymore when bdrv_drain_all_end()
5104 if (bs
->quiesce_counter
) {
5105 bdrv_drain_all_end_quiesce(bs
);
5109 void bdrv_close_all(void)
5111 GLOBAL_STATE_CODE();
5112 assert(job_next(NULL
) == NULL
);
5114 /* Drop references from requests still in flight, such as canceled block
5115 * jobs whose AIO context has not been polled yet */
5118 blk_remove_all_bs();
5119 blockdev_close_all_bdrv_states();
5121 assert(QTAILQ_EMPTY(&all_bdrv_states
));
5124 static bool should_update_child(BdrvChild
*c
, BlockDriverState
*to
)
5130 if (c
->klass
->stay_at_node
) {
5134 /* If the child @c belongs to the BDS @to, replacing the current
5135 * c->bs by @to would mean to create a loop.
5137 * Such a case occurs when appending a BDS to a backing chain.
5138 * For instance, imagine the following chain:
5140 * guest device -> node A -> further backing chain...
5142 * Now we create a new BDS B which we want to put on top of this
5143 * chain, so we first attach A as its backing node:
5148 * guest device -> node A -> further backing chain...
5150 * Finally we want to replace A by B. When doing that, we want to
5151 * replace all pointers to A by pointers to B -- except for the
5152 * pointer from B because (1) that would create a loop, and (2)
5153 * that pointer should simply stay intact:
5155 * guest device -> node B
5158 * node A -> further backing chain...
5160 * In general, when replacing a node A (c->bs) by a node B (@to),
5161 * if A is a child of B, that means we cannot replace A by B there
5162 * because that would create a loop. Silently detaching A from B
5163 * is also not really an option. So overall just leaving A in
5164 * place there is the most sensible choice.
5166 * We would also create a loop in any cases where @c is only
5167 * indirectly referenced by @to. Prevent this by returning false
5168 * if @c is found (by breadth-first search) anywhere in the whole
5173 found
= g_hash_table_new(NULL
, NULL
);
5174 g_hash_table_add(found
, to
);
5175 queue
= g_queue_new();
5176 g_queue_push_tail(queue
, to
);
5178 while (!g_queue_is_empty(queue
)) {
5179 BlockDriverState
*v
= g_queue_pop_head(queue
);
5182 QLIST_FOREACH(c2
, &v
->children
, next
) {
5188 if (g_hash_table_contains(found
, c2
->bs
)) {
5192 g_queue_push_tail(queue
, c2
->bs
);
5193 g_hash_table_add(found
, c2
->bs
);
5197 g_queue_free(queue
);
5198 g_hash_table_destroy(found
);
5203 static void bdrv_remove_child_commit(void *opaque
)
5205 GLOBAL_STATE_CODE();
5206 bdrv_child_free(opaque
);
5209 static TransactionActionDrv bdrv_remove_child_drv
= {
5210 .commit
= bdrv_remove_child_commit
,
5213 /* Function doesn't update permissions, caller is responsible for this. */
5214 static void bdrv_remove_child(BdrvChild
*child
, Transaction
*tran
)
5221 BlockDriverState
*bs
= child
->bs
;
5222 bdrv_drained_begin(bs
);
5223 bdrv_replace_child_tran(child
, NULL
, tran
);
5224 bdrv_drained_end(bs
);
5227 tran_add(tran
, &bdrv_remove_child_drv
, child
);
5230 static void undrain_on_clean_cb(void *opaque
)
5232 bdrv_drained_end(opaque
);
5235 static TransactionActionDrv undrain_on_clean
= {
5236 .clean
= undrain_on_clean_cb
,
5239 static int bdrv_replace_node_noperm(BlockDriverState
*from
,
5240 BlockDriverState
*to
,
5241 bool auto_skip
, Transaction
*tran
,
5244 BdrvChild
*c
, *next
;
5246 GLOBAL_STATE_CODE();
5248 bdrv_drained_begin(from
);
5249 bdrv_drained_begin(to
);
5250 tran_add(tran
, &undrain_on_clean
, from
);
5251 tran_add(tran
, &undrain_on_clean
, to
);
5253 QLIST_FOREACH_SAFE(c
, &from
->parents
, next_parent
, next
) {
5254 assert(c
->bs
== from
);
5255 if (!should_update_child(c
, to
)) {
5259 error_setg(errp
, "Should not change '%s' link to '%s'",
5260 c
->name
, from
->node_name
);
5264 error_setg(errp
, "Cannot change '%s' link to '%s'",
5265 c
->name
, from
->node_name
);
5268 bdrv_replace_child_tran(c
, to
, tran
);
5275 * With auto_skip=true bdrv_replace_node_common skips updating from parents
5276 * if it creates a parent-child relation loop or if parent is block-job.
5278 * With auto_skip=false the error is returned if from has a parent which should
5281 * With @detach_subchain=true @to must be in a backing chain of @from. In this
5282 * case backing link of the cow-parent of @to is removed.
5284 static int bdrv_replace_node_common(BlockDriverState
*from
,
5285 BlockDriverState
*to
,
5286 bool auto_skip
, bool detach_subchain
,
5289 Transaction
*tran
= tran_new();
5290 g_autoptr(GSList
) refresh_list
= NULL
;
5291 BlockDriverState
*to_cow_parent
= NULL
;
5294 GLOBAL_STATE_CODE();
5296 if (detach_subchain
) {
5297 assert(bdrv_chain_contains(from
, to
));
5299 for (to_cow_parent
= from
;
5300 bdrv_filter_or_cow_bs(to_cow_parent
) != to
;
5301 to_cow_parent
= bdrv_filter_or_cow_bs(to_cow_parent
))
5307 /* Make sure that @from doesn't go away until we have successfully attached
5308 * all of its parents to @to. */
5311 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
5312 assert(bdrv_get_aio_context(from
) == bdrv_get_aio_context(to
));
5313 bdrv_drained_begin(from
);
5316 * Do the replacement without permission update.
5317 * Replacement may influence the permissions, we should calculate new
5318 * permissions based on new graph. If we fail, we'll roll-back the
5321 ret
= bdrv_replace_node_noperm(from
, to
, auto_skip
, tran
, errp
);
5326 if (detach_subchain
) {
5327 bdrv_remove_child(bdrv_filter_or_cow_child(to_cow_parent
), tran
);
5330 refresh_list
= g_slist_prepend(refresh_list
, to
);
5331 refresh_list
= g_slist_prepend(refresh_list
, from
);
5333 ret
= bdrv_list_refresh_perms(refresh_list
, NULL
, tran
, errp
);
5341 tran_finalize(tran
, ret
);
5343 bdrv_drained_end(from
);
5349 int bdrv_replace_node(BlockDriverState
*from
, BlockDriverState
*to
,
5352 GLOBAL_STATE_CODE();
5354 return bdrv_replace_node_common(from
, to
, true, false, errp
);
5357 int bdrv_drop_filter(BlockDriverState
*bs
, Error
**errp
)
5359 GLOBAL_STATE_CODE();
5361 return bdrv_replace_node_common(bs
, bdrv_filter_or_cow_bs(bs
), true, true,
5366 * Add new bs contents at the top of an image chain while the chain is
5367 * live, while keeping required fields on the top layer.
5369 * This will modify the BlockDriverState fields, and swap contents
5370 * between bs_new and bs_top. Both bs_new and bs_top are modified.
5372 * bs_new must not be attached to a BlockBackend and must not have backing
5375 * This function does not create any image files.
5377 * The caller must hold the AioContext lock for @bs_top.
5379 int bdrv_append(BlockDriverState
*bs_new
, BlockDriverState
*bs_top
,
5384 Transaction
*tran
= tran_new();
5385 AioContext
*old_context
, *new_context
= NULL
;
5387 GLOBAL_STATE_CODE();
5389 assert(!bs_new
->backing
);
5391 old_context
= bdrv_get_aio_context(bs_top
);
5393 child
= bdrv_attach_child_noperm(bs_new
, bs_top
, "backing",
5394 &child_of_bds
, bdrv_backing_role(bs_new
),
5402 * bdrv_attach_child_noperm could change the AioContext of bs_top.
5403 * bdrv_replace_node_noperm calls bdrv_drained_begin, so let's temporarily
5404 * hold the new AioContext, since bdrv_drained_begin calls BDRV_POLL_WHILE
5405 * that assumes the new lock is taken.
5407 new_context
= bdrv_get_aio_context(bs_top
);
5409 if (old_context
!= new_context
) {
5410 aio_context_release(old_context
);
5411 aio_context_acquire(new_context
);
5414 ret
= bdrv_replace_node_noperm(bs_top
, bs_new
, true, tran
, errp
);
5419 ret
= bdrv_refresh_perms(bs_new
, tran
, errp
);
5421 tran_finalize(tran
, ret
);
5423 bdrv_graph_rdlock_main_loop();
5424 bdrv_refresh_limits(bs_top
, NULL
, NULL
);
5425 bdrv_graph_rdunlock_main_loop();
5427 if (new_context
&& old_context
!= new_context
) {
5428 aio_context_release(new_context
);
5429 aio_context_acquire(old_context
);
5435 /* Not for empty child */
5436 int bdrv_replace_child_bs(BdrvChild
*child
, BlockDriverState
*new_bs
,
5440 Transaction
*tran
= tran_new();
5441 g_autoptr(GSList
) refresh_list
= NULL
;
5442 BlockDriverState
*old_bs
= child
->bs
;
5444 GLOBAL_STATE_CODE();
5447 bdrv_drained_begin(old_bs
);
5448 bdrv_drained_begin(new_bs
);
5450 bdrv_replace_child_tran(child
, new_bs
, tran
);
5452 refresh_list
= g_slist_prepend(refresh_list
, old_bs
);
5453 refresh_list
= g_slist_prepend(refresh_list
, new_bs
);
5455 ret
= bdrv_list_refresh_perms(refresh_list
, NULL
, tran
, errp
);
5457 tran_finalize(tran
, ret
);
5459 bdrv_drained_end(old_bs
);
5460 bdrv_drained_end(new_bs
);
5466 static void bdrv_delete(BlockDriverState
*bs
)
5468 assert(bdrv_op_blocker_is_empty(bs
));
5469 assert(!bs
->refcnt
);
5470 GLOBAL_STATE_CODE();
5472 /* remove from list, if necessary */
5473 if (bs
->node_name
[0] != '\0') {
5474 QTAILQ_REMOVE(&graph_bdrv_states
, bs
, node_list
);
5476 QTAILQ_REMOVE(&all_bdrv_states
, bs
, bs_list
);
5480 qemu_mutex_destroy(&bs
->reqs_lock
);
5487 * Replace @bs by newly created block node.
5489 * @options is a QDict of options to pass to the block drivers, or NULL for an
5490 * empty set of options. The reference to the QDict belongs to the block layer
5491 * after the call (even on failure), so if the caller intends to reuse the
5492 * dictionary, it needs to use qobject_ref() before calling bdrv_open.
5494 * The caller holds the AioContext lock for @bs. It must make sure that @bs
5495 * stays in the same AioContext, i.e. @options must not refer to nodes in a
5496 * different AioContext.
5498 BlockDriverState
*bdrv_insert_node(BlockDriverState
*bs
, QDict
*options
,
5499 int flags
, Error
**errp
)
5503 AioContext
*ctx
= bdrv_get_aio_context(bs
);
5504 BlockDriverState
*new_node_bs
= NULL
;
5505 const char *drvname
, *node_name
;
5508 drvname
= qdict_get_try_str(options
, "driver");
5510 error_setg(errp
, "driver is not specified");
5514 drv
= bdrv_find_format(drvname
);
5516 error_setg(errp
, "Unknown driver: '%s'", drvname
);
5520 node_name
= qdict_get_try_str(options
, "node-name");
5522 GLOBAL_STATE_CODE();
5524 aio_context_release(ctx
);
5525 aio_context_acquire(qemu_get_aio_context());
5526 new_node_bs
= bdrv_new_open_driver_opts(drv
, node_name
, options
, flags
,
5528 aio_context_release(qemu_get_aio_context());
5529 aio_context_acquire(ctx
);
5530 assert(bdrv_get_aio_context(bs
) == ctx
);
5532 options
= NULL
; /* bdrv_new_open_driver() eats options */
5534 error_prepend(errp
, "Could not create node: ");
5538 bdrv_drained_begin(bs
);
5539 ret
= bdrv_replace_node(bs
, new_node_bs
, errp
);
5540 bdrv_drained_end(bs
);
5543 error_prepend(errp
, "Could not replace node: ");
5550 qobject_unref(options
);
5551 bdrv_unref(new_node_bs
);
5556 * Run consistency checks on an image
5558 * Returns 0 if the check could be completed (it doesn't mean that the image is
5559 * free of errors) or -errno when an internal error occurred. The results of the
5560 * check are stored in res.
5562 int coroutine_fn
bdrv_co_check(BlockDriverState
*bs
,
5563 BdrvCheckResult
*res
, BdrvCheckMode fix
)
5566 assert_bdrv_graph_readable();
5567 if (bs
->drv
== NULL
) {
5570 if (bs
->drv
->bdrv_co_check
== NULL
) {
5574 memset(res
, 0, sizeof(*res
));
5575 return bs
->drv
->bdrv_co_check(bs
, res
, fix
);
5581 * -EINVAL - backing format specified, but no file
5582 * -ENOSPC - can't update the backing file because no space is left in the
5584 * -ENOTSUP - format driver doesn't support changing the backing file
5586 int bdrv_change_backing_file(BlockDriverState
*bs
, const char *backing_file
,
5587 const char *backing_fmt
, bool require
)
5589 BlockDriver
*drv
= bs
->drv
;
5592 GLOBAL_STATE_CODE();
5598 /* Backing file format doesn't make sense without a backing file */
5599 if (backing_fmt
&& !backing_file
) {
5603 if (require
&& backing_file
&& !backing_fmt
) {
5607 if (drv
->bdrv_change_backing_file
!= NULL
) {
5608 ret
= drv
->bdrv_change_backing_file(bs
, backing_file
, backing_fmt
);
5614 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
), backing_file
?: "");
5615 pstrcpy(bs
->backing_format
, sizeof(bs
->backing_format
), backing_fmt
?: "");
5616 pstrcpy(bs
->auto_backing_file
, sizeof(bs
->auto_backing_file
),
5617 backing_file
?: "");
5623 * Finds the first non-filter node above bs in the chain between
5624 * active and bs. The returned node is either an immediate parent of
5625 * bs, or there are only filter nodes between the two.
5627 * Returns NULL if bs is not found in active's image chain,
5628 * or if active == bs.
5630 * Returns the bottommost base image if bs == NULL.
5632 BlockDriverState
*bdrv_find_overlay(BlockDriverState
*active
,
5633 BlockDriverState
*bs
)
5636 GLOBAL_STATE_CODE();
5638 bs
= bdrv_skip_filters(bs
);
5639 active
= bdrv_skip_filters(active
);
5642 BlockDriverState
*next
= bdrv_backing_chain_next(active
);
5652 /* Given a BDS, searches for the base layer. */
5653 BlockDriverState
*bdrv_find_base(BlockDriverState
*bs
)
5655 GLOBAL_STATE_CODE();
5657 return bdrv_find_overlay(bs
, NULL
);
5661 * Return true if at least one of the COW (backing) and filter links
5662 * between @bs and @base is frozen. @errp is set if that's the case.
5663 * @base must be reachable from @bs, or NULL.
5665 bool bdrv_is_backing_chain_frozen(BlockDriverState
*bs
, BlockDriverState
*base
,
5668 BlockDriverState
*i
;
5671 GLOBAL_STATE_CODE();
5673 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5674 child
= bdrv_filter_or_cow_child(i
);
5676 if (child
&& child
->frozen
) {
5677 error_setg(errp
, "Cannot change '%s' link from '%s' to '%s'",
5678 child
->name
, i
->node_name
, child
->bs
->node_name
);
5687 * Freeze all COW (backing) and filter links between @bs and @base.
5688 * If any of the links is already frozen the operation is aborted and
5689 * none of the links are modified.
5690 * @base must be reachable from @bs, or NULL.
5691 * Returns 0 on success. On failure returns < 0 and sets @errp.
5693 int bdrv_freeze_backing_chain(BlockDriverState
*bs
, BlockDriverState
*base
,
5696 BlockDriverState
*i
;
5699 GLOBAL_STATE_CODE();
5701 if (bdrv_is_backing_chain_frozen(bs
, base
, errp
)) {
5705 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5706 child
= bdrv_filter_or_cow_child(i
);
5707 if (child
&& child
->bs
->never_freeze
) {
5708 error_setg(errp
, "Cannot freeze '%s' link to '%s'",
5709 child
->name
, child
->bs
->node_name
);
5714 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5715 child
= bdrv_filter_or_cow_child(i
);
5717 child
->frozen
= true;
5725 * Unfreeze all COW (backing) and filter links between @bs and @base.
5726 * The caller must ensure that all links are frozen before using this
5728 * @base must be reachable from @bs, or NULL.
5730 void bdrv_unfreeze_backing_chain(BlockDriverState
*bs
, BlockDriverState
*base
)
5732 BlockDriverState
*i
;
5735 GLOBAL_STATE_CODE();
5737 for (i
= bs
; i
!= base
; i
= child_bs(child
)) {
5738 child
= bdrv_filter_or_cow_child(i
);
5740 assert(child
->frozen
);
5741 child
->frozen
= false;
5747 * Drops images above 'base' up to and including 'top', and sets the image
5748 * above 'top' to have base as its backing file.
5750 * Requires that the overlay to 'top' is opened r/w, so that the backing file
5751 * information in 'bs' can be properly updated.
5753 * E.g., this will convert the following chain:
5754 * bottom <- base <- intermediate <- top <- active
5758 * bottom <- base <- active
5760 * It is allowed for bottom==base, in which case it converts:
5762 * base <- intermediate <- top <- active
5768 * If backing_file_str is non-NULL, it will be used when modifying top's
5769 * overlay image metadata.
5772 * if active == top, that is considered an error
5775 int bdrv_drop_intermediate(BlockDriverState
*top
, BlockDriverState
*base
,
5776 const char *backing_file_str
)
5778 BlockDriverState
*explicit_top
= top
;
5779 bool update_inherits_from
;
5781 Error
*local_err
= NULL
;
5783 g_autoptr(GSList
) updated_children
= NULL
;
5786 GLOBAL_STATE_CODE();
5789 bdrv_drained_begin(base
);
5791 if (!top
->drv
|| !base
->drv
) {
5795 /* Make sure that base is in the backing chain of top */
5796 if (!bdrv_chain_contains(top
, base
)) {
5800 /* If 'base' recursively inherits from 'top' then we should set
5801 * base->inherits_from to top->inherits_from after 'top' and all
5802 * other intermediate nodes have been dropped.
5803 * If 'top' is an implicit node (e.g. "commit_top") we should skip
5804 * it because no one inherits from it. We use explicit_top for that. */
5805 explicit_top
= bdrv_skip_implicit_filters(explicit_top
);
5806 update_inherits_from
= bdrv_inherits_from_recursive(base
, explicit_top
);
5808 /* success - we can delete the intermediate states, and link top->base */
5809 if (!backing_file_str
) {
5810 bdrv_refresh_filename(base
);
5811 backing_file_str
= base
->filename
;
5814 QLIST_FOREACH(c
, &top
->parents
, next_parent
) {
5815 updated_children
= g_slist_prepend(updated_children
, c
);
5819 * It seems correct to pass detach_subchain=true here, but it triggers
5820 * one more yet not fixed bug, when due to nested aio_poll loop we switch to
5821 * another drained section, which modify the graph (for example, removing
5822 * the child, which we keep in updated_children list). So, it's a TODO.
5824 * Note, bug triggered if pass detach_subchain=true here and run
5825 * test-bdrv-drain. test_drop_intermediate_poll() test-case will crash.
5828 bdrv_replace_node_common(top
, base
, false, false, &local_err
);
5830 error_report_err(local_err
);
5834 for (p
= updated_children
; p
; p
= p
->next
) {
5837 if (c
->klass
->update_filename
) {
5838 ret
= c
->klass
->update_filename(c
, base
, backing_file_str
,
5842 * TODO: Actually, we want to rollback all previous iterations
5843 * of this loop, and (which is almost impossible) previous
5844 * bdrv_replace_node()...
5846 * Note, that c->klass->update_filename may lead to permission
5847 * update, so it's a bad idea to call it inside permission
5848 * update transaction of bdrv_replace_node.
5850 error_report_err(local_err
);
5856 if (update_inherits_from
) {
5857 base
->inherits_from
= explicit_top
->inherits_from
;
5862 bdrv_drained_end(base
);
5868 * Implementation of BlockDriver.bdrv_co_get_allocated_file_size() that
5869 * sums the size of all data-bearing children. (This excludes backing
5872 static int64_t coroutine_fn GRAPH_RDLOCK
5873 bdrv_sum_allocated_file_size(BlockDriverState
*bs
)
5876 int64_t child_size
, sum
= 0;
5878 QLIST_FOREACH(child
, &bs
->children
, next
) {
5879 if (child
->role
& (BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
|
5880 BDRV_CHILD_FILTERED
))
5882 child_size
= bdrv_co_get_allocated_file_size(child
->bs
);
5883 if (child_size
< 0) {
5894 * Length of a allocated file in bytes. Sparse files are counted by actual
5895 * allocated space. Return < 0 if error or unknown.
5897 int64_t coroutine_fn
bdrv_co_get_allocated_file_size(BlockDriverState
*bs
)
5899 BlockDriver
*drv
= bs
->drv
;
5901 assert_bdrv_graph_readable();
5906 if (drv
->bdrv_co_get_allocated_file_size
) {
5907 return drv
->bdrv_co_get_allocated_file_size(bs
);
5910 if (drv
->bdrv_file_open
) {
5912 * Protocol drivers default to -ENOTSUP (most of their data is
5913 * not stored in any of their children (if they even have any),
5914 * so there is no generic way to figure it out).
5917 } else if (drv
->is_filter
) {
5918 /* Filter drivers default to the size of their filtered child */
5919 return bdrv_co_get_allocated_file_size(bdrv_filter_bs(bs
));
5921 /* Other drivers default to summing their children's sizes */
5922 return bdrv_sum_allocated_file_size(bs
);
5928 * @drv: Format driver
5929 * @opts: Creation options for new image
5930 * @in_bs: Existing image containing data for new image (may be NULL)
5931 * @errp: Error object
5932 * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo())
5935 * Calculate file size required to create a new image.
5937 * If @in_bs is given then space for allocated clusters and zero clusters
5938 * from that image are included in the calculation. If @opts contains a
5939 * backing file that is shared by @in_bs then backing clusters may be omitted
5940 * from the calculation.
5942 * If @in_bs is NULL then the calculation includes no allocated clusters
5943 * unless a preallocation option is given in @opts.
5945 * Note that @in_bs may use a different BlockDriver from @drv.
5947 * If an error occurs the @errp pointer is set.
5949 BlockMeasureInfo
*bdrv_measure(BlockDriver
*drv
, QemuOpts
*opts
,
5950 BlockDriverState
*in_bs
, Error
**errp
)
5953 if (!drv
->bdrv_measure
) {
5954 error_setg(errp
, "Block driver '%s' does not support size measurement",
5959 return drv
->bdrv_measure(opts
, in_bs
, errp
);
5963 * Return number of sectors on success, -errno on error.
5965 int64_t coroutine_fn
bdrv_co_nb_sectors(BlockDriverState
*bs
)
5967 BlockDriver
*drv
= bs
->drv
;
5969 assert_bdrv_graph_readable();
5974 if (bs
->bl
.has_variable_length
) {
5975 int ret
= bdrv_co_refresh_total_sectors(bs
, bs
->total_sectors
);
5980 return bs
->total_sectors
;
5984 * This wrapper is written by hand because this function is in the hot I/O path,
5985 * via blk_get_geometry.
5987 int64_t coroutine_mixed_fn
bdrv_nb_sectors(BlockDriverState
*bs
)
5989 BlockDriver
*drv
= bs
->drv
;
5995 if (bs
->bl
.has_variable_length
) {
5996 int ret
= bdrv_refresh_total_sectors(bs
, bs
->total_sectors
);
6002 return bs
->total_sectors
;
6006 * Return length in bytes on success, -errno on error.
6007 * The length is always a multiple of BDRV_SECTOR_SIZE.
6009 int64_t coroutine_fn
bdrv_co_getlength(BlockDriverState
*bs
)
6013 assert_bdrv_graph_readable();
6015 ret
= bdrv_co_nb_sectors(bs
);
6019 if (ret
> INT64_MAX
/ BDRV_SECTOR_SIZE
) {
6022 return ret
* BDRV_SECTOR_SIZE
;
6025 bool bdrv_is_sg(BlockDriverState
*bs
)
6032 * Return whether the given node supports compressed writes.
6034 bool bdrv_supports_compressed_writes(BlockDriverState
*bs
)
6036 BlockDriverState
*filtered
;
6039 if (!bs
->drv
|| !block_driver_can_compress(bs
->drv
)) {
6043 filtered
= bdrv_filter_bs(bs
);
6046 * Filters can only forward compressed writes, so we have to
6049 return bdrv_supports_compressed_writes(filtered
);
6055 const char *bdrv_get_format_name(BlockDriverState
*bs
)
6058 return bs
->drv
? bs
->drv
->format_name
: NULL
;
6061 static int qsort_strcmp(const void *a
, const void *b
)
6063 return strcmp(*(char *const *)a
, *(char *const *)b
);
6066 void bdrv_iterate_format(void (*it
)(void *opaque
, const char *name
),
6067 void *opaque
, bool read_only
)
6072 const char **formats
= NULL
;
6074 GLOBAL_STATE_CODE();
6076 QLIST_FOREACH(drv
, &bdrv_drivers
, list
) {
6077 if (drv
->format_name
) {
6081 if (use_bdrv_whitelist
&& !bdrv_is_whitelisted(drv
, read_only
)) {
6085 while (formats
&& i
&& !found
) {
6086 found
= !strcmp(formats
[--i
], drv
->format_name
);
6090 formats
= g_renew(const char *, formats
, count
+ 1);
6091 formats
[count
++] = drv
->format_name
;
6096 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); i
++) {
6097 const char *format_name
= block_driver_modules
[i
].format_name
;
6103 if (use_bdrv_whitelist
&&
6104 !bdrv_format_is_whitelisted(format_name
, read_only
)) {
6108 while (formats
&& j
&& !found
) {
6109 found
= !strcmp(formats
[--j
], format_name
);
6113 formats
= g_renew(const char *, formats
, count
+ 1);
6114 formats
[count
++] = format_name
;
6119 qsort(formats
, count
, sizeof(formats
[0]), qsort_strcmp
);
6121 for (i
= 0; i
< count
; i
++) {
6122 it(opaque
, formats
[i
]);
6128 /* This function is to find a node in the bs graph */
6129 BlockDriverState
*bdrv_find_node(const char *node_name
)
6131 BlockDriverState
*bs
;
6134 GLOBAL_STATE_CODE();
6136 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
6137 if (!strcmp(node_name
, bs
->node_name
)) {
6144 /* Put this QMP function here so it can access the static graph_bdrv_states. */
6145 BlockDeviceInfoList
*bdrv_named_nodes_list(bool flat
,
6148 BlockDeviceInfoList
*list
;
6149 BlockDriverState
*bs
;
6151 GLOBAL_STATE_CODE();
6154 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
6155 BlockDeviceInfo
*info
= bdrv_block_device_info(NULL
, bs
, flat
, errp
);
6157 qapi_free_BlockDeviceInfoList(list
);
6160 QAPI_LIST_PREPEND(list
, info
);
6166 typedef struct XDbgBlockGraphConstructor
{
6167 XDbgBlockGraph
*graph
;
6168 GHashTable
*graph_nodes
;
6169 } XDbgBlockGraphConstructor
;
6171 static XDbgBlockGraphConstructor
*xdbg_graph_new(void)
6173 XDbgBlockGraphConstructor
*gr
= g_new(XDbgBlockGraphConstructor
, 1);
6175 gr
->graph
= g_new0(XDbgBlockGraph
, 1);
6176 gr
->graph_nodes
= g_hash_table_new(NULL
, NULL
);
6181 static XDbgBlockGraph
*xdbg_graph_finalize(XDbgBlockGraphConstructor
*gr
)
6183 XDbgBlockGraph
*graph
= gr
->graph
;
6185 g_hash_table_destroy(gr
->graph_nodes
);
6191 static uintptr_t xdbg_graph_node_num(XDbgBlockGraphConstructor
*gr
, void *node
)
6193 uintptr_t ret
= (uintptr_t)g_hash_table_lookup(gr
->graph_nodes
, node
);
6200 * Start counting from 1, not 0, because 0 interferes with not-found (NULL)
6201 * answer of g_hash_table_lookup.
6203 ret
= g_hash_table_size(gr
->graph_nodes
) + 1;
6204 g_hash_table_insert(gr
->graph_nodes
, node
, (void *)ret
);
6209 static void xdbg_graph_add_node(XDbgBlockGraphConstructor
*gr
, void *node
,
6210 XDbgBlockGraphNodeType type
, const char *name
)
6212 XDbgBlockGraphNode
*n
;
6214 n
= g_new0(XDbgBlockGraphNode
, 1);
6216 n
->id
= xdbg_graph_node_num(gr
, node
);
6218 n
->name
= g_strdup(name
);
6220 QAPI_LIST_PREPEND(gr
->graph
->nodes
, n
);
6223 static void xdbg_graph_add_edge(XDbgBlockGraphConstructor
*gr
, void *parent
,
6224 const BdrvChild
*child
)
6226 BlockPermission qapi_perm
;
6227 XDbgBlockGraphEdge
*edge
;
6228 GLOBAL_STATE_CODE();
6230 edge
= g_new0(XDbgBlockGraphEdge
, 1);
6232 edge
->parent
= xdbg_graph_node_num(gr
, parent
);
6233 edge
->child
= xdbg_graph_node_num(gr
, child
->bs
);
6234 edge
->name
= g_strdup(child
->name
);
6236 for (qapi_perm
= 0; qapi_perm
< BLOCK_PERMISSION__MAX
; qapi_perm
++) {
6237 uint64_t flag
= bdrv_qapi_perm_to_blk_perm(qapi_perm
);
6239 if (flag
& child
->perm
) {
6240 QAPI_LIST_PREPEND(edge
->perm
, qapi_perm
);
6242 if (flag
& child
->shared_perm
) {
6243 QAPI_LIST_PREPEND(edge
->shared_perm
, qapi_perm
);
6247 QAPI_LIST_PREPEND(gr
->graph
->edges
, edge
);
6251 XDbgBlockGraph
*bdrv_get_xdbg_block_graph(Error
**errp
)
6255 BlockDriverState
*bs
;
6257 XDbgBlockGraphConstructor
*gr
= xdbg_graph_new();
6259 GLOBAL_STATE_CODE();
6261 for (blk
= blk_all_next(NULL
); blk
; blk
= blk_all_next(blk
)) {
6262 char *allocated_name
= NULL
;
6263 const char *name
= blk_name(blk
);
6266 name
= allocated_name
= blk_get_attached_dev_id(blk
);
6268 xdbg_graph_add_node(gr
, blk
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND
,
6270 g_free(allocated_name
);
6271 if (blk_root(blk
)) {
6272 xdbg_graph_add_edge(gr
, blk
, blk_root(blk
));
6276 WITH_JOB_LOCK_GUARD() {
6277 for (job
= block_job_next_locked(NULL
); job
;
6278 job
= block_job_next_locked(job
)) {
6281 xdbg_graph_add_node(gr
, job
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB
,
6283 for (el
= job
->nodes
; el
; el
= el
->next
) {
6284 xdbg_graph_add_edge(gr
, job
, (BdrvChild
*)el
->data
);
6289 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
6290 xdbg_graph_add_node(gr
, bs
, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_DRIVER
,
6292 QLIST_FOREACH(child
, &bs
->children
, next
) {
6293 xdbg_graph_add_edge(gr
, bs
, child
);
6297 return xdbg_graph_finalize(gr
);
6300 BlockDriverState
*bdrv_lookup_bs(const char *device
,
6301 const char *node_name
,
6305 BlockDriverState
*bs
;
6307 GLOBAL_STATE_CODE();
6310 blk
= blk_by_name(device
);
6315 error_setg(errp
, "Device '%s' has no medium", device
);
6323 bs
= bdrv_find_node(node_name
);
6330 error_setg(errp
, "Cannot find device=\'%s\' nor node-name=\'%s\'",
6331 device
? device
: "",
6332 node_name
? node_name
: "");
6336 /* If 'base' is in the same chain as 'top', return true. Otherwise,
6337 * return false. If either argument is NULL, return false. */
6338 bool bdrv_chain_contains(BlockDriverState
*top
, BlockDriverState
*base
)
6341 GLOBAL_STATE_CODE();
6343 while (top
&& top
!= base
) {
6344 top
= bdrv_filter_or_cow_bs(top
);
6350 BlockDriverState
*bdrv_next_node(BlockDriverState
*bs
)
6352 GLOBAL_STATE_CODE();
6354 return QTAILQ_FIRST(&graph_bdrv_states
);
6356 return QTAILQ_NEXT(bs
, node_list
);
6359 BlockDriverState
*bdrv_next_all_states(BlockDriverState
*bs
)
6361 GLOBAL_STATE_CODE();
6363 return QTAILQ_FIRST(&all_bdrv_states
);
6365 return QTAILQ_NEXT(bs
, bs_list
);
6368 const char *bdrv_get_node_name(const BlockDriverState
*bs
)
6371 return bs
->node_name
;
6374 const char *bdrv_get_parent_name(const BlockDriverState
*bs
)
6380 /* If multiple parents have a name, just pick the first one. */
6381 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
6382 if (c
->klass
->get_name
) {
6383 name
= c
->klass
->get_name(c
);
6384 if (name
&& *name
) {
6393 /* TODO check what callers really want: bs->node_name or blk_name() */
6394 const char *bdrv_get_device_name(const BlockDriverState
*bs
)
6397 return bdrv_get_parent_name(bs
) ?: "";
6400 /* This can be used to identify nodes that might not have a device
6401 * name associated. Since node and device names live in the same
6402 * namespace, the result is unambiguous. The exception is if both are
6403 * absent, then this returns an empty (non-null) string. */
6404 const char *bdrv_get_device_or_node_name(const BlockDriverState
*bs
)
6407 return bdrv_get_parent_name(bs
) ?: bs
->node_name
;
6410 int bdrv_get_flags(BlockDriverState
*bs
)
6413 return bs
->open_flags
;
6416 int bdrv_has_zero_init_1(BlockDriverState
*bs
)
6418 GLOBAL_STATE_CODE();
6422 int bdrv_has_zero_init(BlockDriverState
*bs
)
6424 BlockDriverState
*filtered
;
6425 GLOBAL_STATE_CODE();
6431 /* If BS is a copy on write image, it is initialized to
6432 the contents of the base image, which may not be zeroes. */
6433 if (bdrv_cow_child(bs
)) {
6436 if (bs
->drv
->bdrv_has_zero_init
) {
6437 return bs
->drv
->bdrv_has_zero_init(bs
);
6440 filtered
= bdrv_filter_bs(bs
);
6442 return bdrv_has_zero_init(filtered
);
6449 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState
*bs
)
6452 if (!(bs
->open_flags
& BDRV_O_UNMAP
)) {
6456 return bs
->supported_zero_flags
& BDRV_REQ_MAY_UNMAP
;
6459 void bdrv_get_backing_filename(BlockDriverState
*bs
,
6460 char *filename
, int filename_size
)
6463 pstrcpy(filename
, filename_size
, bs
->backing_file
);
6466 int coroutine_fn
bdrv_co_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
6469 BlockDriver
*drv
= bs
->drv
;
6471 assert_bdrv_graph_readable();
6473 /* if bs->drv == NULL, bs is closed, so there's nothing to do here */
6477 if (!drv
->bdrv_co_get_info
) {
6478 BlockDriverState
*filtered
= bdrv_filter_bs(bs
);
6480 return bdrv_co_get_info(filtered
, bdi
);
6484 memset(bdi
, 0, sizeof(*bdi
));
6485 ret
= drv
->bdrv_co_get_info(bs
, bdi
);
6486 if (bdi
->subcluster_size
== 0) {
6488 * If the driver left this unset, subclusters are not supported.
6489 * Then it is safe to treat each cluster as having only one subcluster.
6491 bdi
->subcluster_size
= bdi
->cluster_size
;
6497 if (bdi
->cluster_size
> BDRV_MAX_ALIGNMENT
) {
6504 ImageInfoSpecific
*bdrv_get_specific_info(BlockDriverState
*bs
,
6507 BlockDriver
*drv
= bs
->drv
;
6509 if (drv
&& drv
->bdrv_get_specific_info
) {
6510 return drv
->bdrv_get_specific_info(bs
, errp
);
6515 BlockStatsSpecific
*bdrv_get_specific_stats(BlockDriverState
*bs
)
6517 BlockDriver
*drv
= bs
->drv
;
6519 if (!drv
|| !drv
->bdrv_get_specific_stats
) {
6522 return drv
->bdrv_get_specific_stats(bs
);
6525 void coroutine_fn
bdrv_co_debug_event(BlockDriverState
*bs
, BlkdebugEvent event
)
6528 assert_bdrv_graph_readable();
6530 if (!bs
|| !bs
->drv
|| !bs
->drv
->bdrv_co_debug_event
) {
6534 bs
->drv
->bdrv_co_debug_event(bs
, event
);
6537 static BlockDriverState
*bdrv_find_debug_node(BlockDriverState
*bs
)
6539 GLOBAL_STATE_CODE();
6540 while (bs
&& bs
->drv
&& !bs
->drv
->bdrv_debug_breakpoint
) {
6541 bs
= bdrv_primary_bs(bs
);
6544 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_breakpoint
) {
6545 assert(bs
->drv
->bdrv_debug_remove_breakpoint
);
6552 int bdrv_debug_breakpoint(BlockDriverState
*bs
, const char *event
,
6555 GLOBAL_STATE_CODE();
6556 bs
= bdrv_find_debug_node(bs
);
6558 return bs
->drv
->bdrv_debug_breakpoint(bs
, event
, tag
);
6564 int bdrv_debug_remove_breakpoint(BlockDriverState
*bs
, const char *tag
)
6566 GLOBAL_STATE_CODE();
6567 bs
= bdrv_find_debug_node(bs
);
6569 return bs
->drv
->bdrv_debug_remove_breakpoint(bs
, tag
);
6575 int bdrv_debug_resume(BlockDriverState
*bs
, const char *tag
)
6577 GLOBAL_STATE_CODE();
6578 while (bs
&& (!bs
->drv
|| !bs
->drv
->bdrv_debug_resume
)) {
6579 bs
= bdrv_primary_bs(bs
);
6582 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_resume
) {
6583 return bs
->drv
->bdrv_debug_resume(bs
, tag
);
6589 bool bdrv_debug_is_suspended(BlockDriverState
*bs
, const char *tag
)
6591 GLOBAL_STATE_CODE();
6592 while (bs
&& bs
->drv
&& !bs
->drv
->bdrv_debug_is_suspended
) {
6593 bs
= bdrv_primary_bs(bs
);
6596 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_is_suspended
) {
6597 return bs
->drv
->bdrv_debug_is_suspended(bs
, tag
);
6603 /* backing_file can either be relative, or absolute, or a protocol. If it is
6604 * relative, it must be relative to the chain. So, passing in bs->filename
6605 * from a BDS as backing_file should not be done, as that may be relative to
6606 * the CWD rather than the chain. */
6607 BlockDriverState
*bdrv_find_backing_image(BlockDriverState
*bs
,
6608 const char *backing_file
)
6610 char *filename_full
= NULL
;
6611 char *backing_file_full
= NULL
;
6612 char *filename_tmp
= NULL
;
6613 int is_protocol
= 0;
6614 bool filenames_refreshed
= false;
6615 BlockDriverState
*curr_bs
= NULL
;
6616 BlockDriverState
*retval
= NULL
;
6617 BlockDriverState
*bs_below
;
6619 GLOBAL_STATE_CODE();
6621 if (!bs
|| !bs
->drv
|| !backing_file
) {
6625 filename_full
= g_malloc(PATH_MAX
);
6626 backing_file_full
= g_malloc(PATH_MAX
);
6628 is_protocol
= path_has_protocol(backing_file
);
6631 * Being largely a legacy function, skip any filters here
6632 * (because filters do not have normal filenames, so they cannot
6633 * match anyway; and allowing json:{} filenames is a bit out of
6636 for (curr_bs
= bdrv_skip_filters(bs
);
6637 bdrv_cow_child(curr_bs
) != NULL
;
6640 bs_below
= bdrv_backing_chain_next(curr_bs
);
6642 if (bdrv_backing_overridden(curr_bs
)) {
6644 * If the backing file was overridden, we can only compare
6645 * directly against the backing node's filename.
6648 if (!filenames_refreshed
) {
6650 * This will automatically refresh all of the
6651 * filenames in the rest of the backing chain, so we
6652 * only need to do this once.
6654 bdrv_refresh_filename(bs_below
);
6655 filenames_refreshed
= true;
6658 if (strcmp(backing_file
, bs_below
->filename
) == 0) {
6662 } else if (is_protocol
|| path_has_protocol(curr_bs
->backing_file
)) {
6664 * If either of the filename paths is actually a protocol, then
6665 * compare unmodified paths; otherwise make paths relative.
6667 char *backing_file_full_ret
;
6669 if (strcmp(backing_file
, curr_bs
->backing_file
) == 0) {
6673 /* Also check against the full backing filename for the image */
6674 backing_file_full_ret
= bdrv_get_full_backing_filename(curr_bs
,
6676 if (backing_file_full_ret
) {
6677 bool equal
= strcmp(backing_file
, backing_file_full_ret
) == 0;
6678 g_free(backing_file_full_ret
);
6685 /* If not an absolute filename path, make it relative to the current
6686 * image's filename path */
6687 filename_tmp
= bdrv_make_absolute_filename(curr_bs
, backing_file
,
6689 /* We are going to compare canonicalized absolute pathnames */
6690 if (!filename_tmp
|| !realpath(filename_tmp
, filename_full
)) {
6691 g_free(filename_tmp
);
6694 g_free(filename_tmp
);
6696 /* We need to make sure the backing filename we are comparing against
6697 * is relative to the current image filename (or absolute) */
6698 filename_tmp
= bdrv_get_full_backing_filename(curr_bs
, NULL
);
6699 if (!filename_tmp
|| !realpath(filename_tmp
, backing_file_full
)) {
6700 g_free(filename_tmp
);
6703 g_free(filename_tmp
);
6705 if (strcmp(backing_file_full
, filename_full
) == 0) {
6712 g_free(filename_full
);
6713 g_free(backing_file_full
);
6717 void bdrv_init(void)
6719 #ifdef CONFIG_BDRV_WHITELIST_TOOLS
6720 use_bdrv_whitelist
= 1;
6722 module_call_init(MODULE_INIT_BLOCK
);
6725 void bdrv_init_with_whitelist(void)
6727 use_bdrv_whitelist
= 1;
6731 int bdrv_activate(BlockDriverState
*bs
, Error
**errp
)
6733 BdrvChild
*child
, *parent
;
6734 Error
*local_err
= NULL
;
6736 BdrvDirtyBitmap
*bm
;
6738 GLOBAL_STATE_CODE();
6744 QLIST_FOREACH(child
, &bs
->children
, next
) {
6745 bdrv_activate(child
->bs
, &local_err
);
6747 error_propagate(errp
, local_err
);
6753 * Update permissions, they may differ for inactive nodes.
6755 * Note that the required permissions of inactive images are always a
6756 * subset of the permissions required after activating the image. This
6757 * allows us to just get the permissions upfront without restricting
6758 * bdrv_co_invalidate_cache().
6760 * It also means that in error cases, we don't have to try and revert to
6761 * the old permissions (which is an operation that could fail, too). We can
6762 * just keep the extended permissions for the next time that an activation
6763 * of the image is tried.
6765 if (bs
->open_flags
& BDRV_O_INACTIVE
) {
6766 bs
->open_flags
&= ~BDRV_O_INACTIVE
;
6767 ret
= bdrv_refresh_perms(bs
, NULL
, errp
);
6769 bs
->open_flags
|= BDRV_O_INACTIVE
;
6773 ret
= bdrv_invalidate_cache(bs
, errp
);
6775 bs
->open_flags
|= BDRV_O_INACTIVE
;
6779 FOR_EACH_DIRTY_BITMAP(bs
, bm
) {
6780 bdrv_dirty_bitmap_skip_store(bm
, false);
6783 ret
= bdrv_refresh_total_sectors(bs
, bs
->total_sectors
);
6785 bs
->open_flags
|= BDRV_O_INACTIVE
;
6786 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
6791 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6792 if (parent
->klass
->activate
) {
6793 parent
->klass
->activate(parent
, &local_err
);
6795 bs
->open_flags
|= BDRV_O_INACTIVE
;
6796 error_propagate(errp
, local_err
);
6805 int coroutine_fn
bdrv_co_invalidate_cache(BlockDriverState
*bs
, Error
**errp
)
6807 Error
*local_err
= NULL
;
6810 assert(!(bs
->open_flags
& BDRV_O_INACTIVE
));
6811 assert_bdrv_graph_readable();
6813 if (bs
->drv
->bdrv_co_invalidate_cache
) {
6814 bs
->drv
->bdrv_co_invalidate_cache(bs
, &local_err
);
6816 error_propagate(errp
, local_err
);
6824 void bdrv_activate_all(Error
**errp
)
6826 BlockDriverState
*bs
;
6827 BdrvNextIterator it
;
6829 GLOBAL_STATE_CODE();
6831 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
6832 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
6835 aio_context_acquire(aio_context
);
6836 ret
= bdrv_activate(bs
, errp
);
6837 aio_context_release(aio_context
);
6839 bdrv_next_cleanup(&it
);
6845 static bool bdrv_has_bds_parent(BlockDriverState
*bs
, bool only_active
)
6848 GLOBAL_STATE_CODE();
6850 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6851 if (parent
->klass
->parent_is_bds
) {
6852 BlockDriverState
*parent_bs
= parent
->opaque
;
6853 if (!only_active
|| !(parent_bs
->open_flags
& BDRV_O_INACTIVE
)) {
6862 static int bdrv_inactivate_recurse(BlockDriverState
*bs
)
6864 BdrvChild
*child
, *parent
;
6866 uint64_t cumulative_perms
, cumulative_shared_perms
;
6868 GLOBAL_STATE_CODE();
6874 /* Make sure that we don't inactivate a child before its parent.
6875 * It will be covered by recursion from the yet active parent. */
6876 if (bdrv_has_bds_parent(bs
, true)) {
6880 assert(!(bs
->open_flags
& BDRV_O_INACTIVE
));
6882 /* Inactivate this node */
6883 if (bs
->drv
->bdrv_inactivate
) {
6884 ret
= bs
->drv
->bdrv_inactivate(bs
);
6890 QLIST_FOREACH(parent
, &bs
->parents
, next_parent
) {
6891 if (parent
->klass
->inactivate
) {
6892 ret
= parent
->klass
->inactivate(parent
);
6899 bdrv_get_cumulative_perm(bs
, &cumulative_perms
,
6900 &cumulative_shared_perms
);
6901 if (cumulative_perms
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) {
6902 /* Our inactive parents still need write access. Inactivation failed. */
6906 bs
->open_flags
|= BDRV_O_INACTIVE
;
6909 * Update permissions, they may differ for inactive nodes.
6910 * We only tried to loosen restrictions, so errors are not fatal, ignore
6913 bdrv_refresh_perms(bs
, NULL
, NULL
);
6915 /* Recursively inactivate children */
6916 QLIST_FOREACH(child
, &bs
->children
, next
) {
6917 ret
= bdrv_inactivate_recurse(child
->bs
);
6926 int bdrv_inactivate_all(void)
6928 BlockDriverState
*bs
= NULL
;
6929 BdrvNextIterator it
;
6931 GSList
*aio_ctxs
= NULL
, *ctx
;
6933 GLOBAL_STATE_CODE();
6935 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
6936 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
6938 if (!g_slist_find(aio_ctxs
, aio_context
)) {
6939 aio_ctxs
= g_slist_prepend(aio_ctxs
, aio_context
);
6940 aio_context_acquire(aio_context
);
6944 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
6945 /* Nodes with BDS parents are covered by recursion from the last
6946 * parent that gets inactivated. Don't inactivate them a second
6947 * time if that has already happened. */
6948 if (bdrv_has_bds_parent(bs
, false)) {
6951 ret
= bdrv_inactivate_recurse(bs
);
6953 bdrv_next_cleanup(&it
);
6959 for (ctx
= aio_ctxs
; ctx
!= NULL
; ctx
= ctx
->next
) {
6960 AioContext
*aio_context
= ctx
->data
;
6961 aio_context_release(aio_context
);
6963 g_slist_free(aio_ctxs
);
6968 /**************************************************************/
6969 /* removable device support */
6972 * Return TRUE if the media is present
6974 bool coroutine_fn
bdrv_co_is_inserted(BlockDriverState
*bs
)
6976 BlockDriver
*drv
= bs
->drv
;
6979 assert_bdrv_graph_readable();
6984 if (drv
->bdrv_co_is_inserted
) {
6985 return drv
->bdrv_co_is_inserted(bs
);
6987 QLIST_FOREACH(child
, &bs
->children
, next
) {
6988 if (!bdrv_co_is_inserted(child
->bs
)) {
6996 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
6998 void coroutine_fn
bdrv_co_eject(BlockDriverState
*bs
, bool eject_flag
)
7000 BlockDriver
*drv
= bs
->drv
;
7002 assert_bdrv_graph_readable();
7004 if (drv
&& drv
->bdrv_co_eject
) {
7005 drv
->bdrv_co_eject(bs
, eject_flag
);
7010 * Lock or unlock the media (if it is locked, the user won't be able
7011 * to eject it manually).
7013 void coroutine_fn
bdrv_co_lock_medium(BlockDriverState
*bs
, bool locked
)
7015 BlockDriver
*drv
= bs
->drv
;
7017 assert_bdrv_graph_readable();
7018 trace_bdrv_lock_medium(bs
, locked
);
7020 if (drv
&& drv
->bdrv_co_lock_medium
) {
7021 drv
->bdrv_co_lock_medium(bs
, locked
);
7025 /* Get a reference to bs */
7026 void bdrv_ref(BlockDriverState
*bs
)
7028 GLOBAL_STATE_CODE();
7032 /* Release a previously grabbed reference to bs.
7033 * If after releasing, reference count is zero, the BlockDriverState is
7035 void bdrv_unref(BlockDriverState
*bs
)
7037 GLOBAL_STATE_CODE();
7041 assert(bs
->refcnt
> 0);
7042 if (--bs
->refcnt
== 0) {
7048 * Release a BlockDriverState reference while holding the graph write lock.
7050 * Calling bdrv_unref() directly is forbidden while holding the graph lock
7051 * because bdrv_close() both involves polling and taking the graph lock
7052 * internally. bdrv_schedule_unref() instead delays decreasing the refcount and
7053 * possibly closing @bs until the graph lock is released.
7055 void bdrv_schedule_unref(BlockDriverState
*bs
)
7060 aio_bh_schedule_oneshot(qemu_get_aio_context(),
7061 (QEMUBHFunc
*) bdrv_unref
, bs
);
7064 struct BdrvOpBlocker
{
7066 QLIST_ENTRY(BdrvOpBlocker
) list
;
7069 bool bdrv_op_is_blocked(BlockDriverState
*bs
, BlockOpType op
, Error
**errp
)
7071 BdrvOpBlocker
*blocker
;
7072 GLOBAL_STATE_CODE();
7073 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
7074 if (!QLIST_EMPTY(&bs
->op_blockers
[op
])) {
7075 blocker
= QLIST_FIRST(&bs
->op_blockers
[op
]);
7076 error_propagate_prepend(errp
, error_copy(blocker
->reason
),
7077 "Node '%s' is busy: ",
7078 bdrv_get_device_or_node_name(bs
));
7084 void bdrv_op_block(BlockDriverState
*bs
, BlockOpType op
, Error
*reason
)
7086 BdrvOpBlocker
*blocker
;
7087 GLOBAL_STATE_CODE();
7088 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
7090 blocker
= g_new0(BdrvOpBlocker
, 1);
7091 blocker
->reason
= reason
;
7092 QLIST_INSERT_HEAD(&bs
->op_blockers
[op
], blocker
, list
);
7095 void bdrv_op_unblock(BlockDriverState
*bs
, BlockOpType op
, Error
*reason
)
7097 BdrvOpBlocker
*blocker
, *next
;
7098 GLOBAL_STATE_CODE();
7099 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
7100 QLIST_FOREACH_SAFE(blocker
, &bs
->op_blockers
[op
], list
, next
) {
7101 if (blocker
->reason
== reason
) {
7102 QLIST_REMOVE(blocker
, list
);
7108 void bdrv_op_block_all(BlockDriverState
*bs
, Error
*reason
)
7111 GLOBAL_STATE_CODE();
7112 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
7113 bdrv_op_block(bs
, i
, reason
);
7117 void bdrv_op_unblock_all(BlockDriverState
*bs
, Error
*reason
)
7120 GLOBAL_STATE_CODE();
7121 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
7122 bdrv_op_unblock(bs
, i
, reason
);
7126 bool bdrv_op_blocker_is_empty(BlockDriverState
*bs
)
7129 GLOBAL_STATE_CODE();
7130 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
7131 if (!QLIST_EMPTY(&bs
->op_blockers
[i
])) {
7139 * Must not be called while holding the lock of an AioContext other than the
7142 void bdrv_img_create(const char *filename
, const char *fmt
,
7143 const char *base_filename
, const char *base_fmt
,
7144 char *options
, uint64_t img_size
, int flags
, bool quiet
,
7147 QemuOptsList
*create_opts
= NULL
;
7148 QemuOpts
*opts
= NULL
;
7149 const char *backing_fmt
, *backing_file
;
7151 BlockDriver
*drv
, *proto_drv
;
7152 Error
*local_err
= NULL
;
7155 GLOBAL_STATE_CODE();
7157 /* Find driver and parse its options */
7158 drv
= bdrv_find_format(fmt
);
7160 error_setg(errp
, "Unknown file format '%s'", fmt
);
7164 proto_drv
= bdrv_find_protocol(filename
, true, errp
);
7169 if (!drv
->create_opts
) {
7170 error_setg(errp
, "Format driver '%s' does not support image creation",
7175 if (!proto_drv
->create_opts
) {
7176 error_setg(errp
, "Protocol driver '%s' does not support image creation",
7177 proto_drv
->format_name
);
7181 aio_context_acquire(qemu_get_aio_context());
7183 /* Create parameter list */
7184 create_opts
= qemu_opts_append(create_opts
, drv
->create_opts
);
7185 create_opts
= qemu_opts_append(create_opts
, proto_drv
->create_opts
);
7187 opts
= qemu_opts_create(create_opts
, NULL
, 0, &error_abort
);
7189 /* Parse -o options */
7191 if (!qemu_opts_do_parse(opts
, options
, NULL
, errp
)) {
7196 if (!qemu_opt_get(opts
, BLOCK_OPT_SIZE
)) {
7197 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, img_size
, &error_abort
);
7198 } else if (img_size
!= UINT64_C(-1)) {
7199 error_setg(errp
, "The image size must be specified only once");
7203 if (base_filename
) {
7204 if (!qemu_opt_set(opts
, BLOCK_OPT_BACKING_FILE
, base_filename
,
7206 error_setg(errp
, "Backing file not supported for file format '%s'",
7213 if (!qemu_opt_set(opts
, BLOCK_OPT_BACKING_FMT
, base_fmt
, NULL
)) {
7214 error_setg(errp
, "Backing file format not supported for file "
7215 "format '%s'", fmt
);
7220 backing_file
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FILE
);
7222 if (!strcmp(filename
, backing_file
)) {
7223 error_setg(errp
, "Error: Trying to create an image with the "
7224 "same filename as the backing file");
7227 if (backing_file
[0] == '\0') {
7228 error_setg(errp
, "Expected backing file name, got empty string");
7233 backing_fmt
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FMT
);
7235 /* The size for the image must always be specified, unless we have a backing
7236 * file and we have not been forbidden from opening it. */
7237 size
= qemu_opt_get_size(opts
, BLOCK_OPT_SIZE
, img_size
);
7238 if (backing_file
&& !(flags
& BDRV_O_NO_BACKING
)) {
7239 BlockDriverState
*bs
;
7242 QDict
*backing_options
= NULL
;
7245 bdrv_get_full_backing_filename_from_filename(filename
, backing_file
,
7250 assert(full_backing
);
7253 * No need to do I/O here, which allows us to open encrypted
7254 * backing images without needing the secret
7257 back_flags
&= ~(BDRV_O_RDWR
| BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
);
7258 back_flags
|= BDRV_O_NO_IO
;
7260 backing_options
= qdict_new();
7262 qdict_put_str(backing_options
, "driver", backing_fmt
);
7264 qdict_put_bool(backing_options
, BDRV_OPT_FORCE_SHARE
, true);
7266 bs
= bdrv_open(full_backing
, NULL
, backing_options
, back_flags
,
7268 g_free(full_backing
);
7270 error_append_hint(&local_err
, "Could not open backing image.\n");
7274 error_setg(&local_err
,
7275 "Backing file specified without backing format");
7276 error_append_hint(&local_err
, "Detected format of %s.\n",
7277 bs
->drv
->format_name
);
7281 /* Opened BS, have no size */
7282 size
= bdrv_getlength(bs
);
7284 error_setg_errno(errp
, -size
, "Could not get size of '%s'",
7289 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, size
, &error_abort
);
7293 /* (backing_file && !(flags & BDRV_O_NO_BACKING)) */
7294 } else if (backing_file
&& !backing_fmt
) {
7295 error_setg(&local_err
,
7296 "Backing file specified without backing format");
7301 error_setg(errp
, "Image creation needs a size parameter");
7306 printf("Formatting '%s', fmt=%s ", filename
, fmt
);
7307 qemu_opts_print(opts
, " ");
7312 ret
= bdrv_create(drv
, filename
, opts
, &local_err
);
7314 if (ret
== -EFBIG
) {
7315 /* This is generally a better message than whatever the driver would
7316 * deliver (especially because of the cluster_size_hint), since that
7317 * is most probably not much different from "image too large". */
7318 const char *cluster_size_hint
= "";
7319 if (qemu_opt_get_size(opts
, BLOCK_OPT_CLUSTER_SIZE
, 0)) {
7320 cluster_size_hint
= " (try using a larger cluster size)";
7322 error_setg(errp
, "The image size is too large for file format '%s'"
7323 "%s", fmt
, cluster_size_hint
);
7324 error_free(local_err
);
7329 qemu_opts_del(opts
);
7330 qemu_opts_free(create_opts
);
7331 error_propagate(errp
, local_err
);
7332 aio_context_release(qemu_get_aio_context());
7335 AioContext
*bdrv_get_aio_context(BlockDriverState
*bs
)
7338 return bs
? bs
->aio_context
: qemu_get_aio_context();
7341 AioContext
*coroutine_fn
bdrv_co_enter(BlockDriverState
*bs
)
7343 Coroutine
*self
= qemu_coroutine_self();
7344 AioContext
*old_ctx
= qemu_coroutine_get_aio_context(self
);
7345 AioContext
*new_ctx
;
7349 * Increase bs->in_flight to ensure that this operation is completed before
7350 * moving the node to a different AioContext. Read new_ctx only afterwards.
7352 bdrv_inc_in_flight(bs
);
7354 new_ctx
= bdrv_get_aio_context(bs
);
7355 aio_co_reschedule_self(new_ctx
);
7359 void coroutine_fn
bdrv_co_leave(BlockDriverState
*bs
, AioContext
*old_ctx
)
7362 aio_co_reschedule_self(old_ctx
);
7363 bdrv_dec_in_flight(bs
);
7366 void coroutine_fn
bdrv_co_lock(BlockDriverState
*bs
)
7368 AioContext
*ctx
= bdrv_get_aio_context(bs
);
7370 /* In the main thread, bs->aio_context won't change concurrently */
7371 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
7374 * We're in coroutine context, so we already hold the lock of the main
7375 * loop AioContext. Don't lock it twice to avoid deadlocks.
7377 assert(qemu_in_coroutine());
7378 if (ctx
!= qemu_get_aio_context()) {
7379 aio_context_acquire(ctx
);
7383 void coroutine_fn
bdrv_co_unlock(BlockDriverState
*bs
)
7385 AioContext
*ctx
= bdrv_get_aio_context(bs
);
7387 assert(qemu_in_coroutine());
7388 if (ctx
!= qemu_get_aio_context()) {
7389 aio_context_release(ctx
);
7393 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier
*ban
)
7395 GLOBAL_STATE_CODE();
7396 QLIST_REMOVE(ban
, list
);
7400 static void bdrv_detach_aio_context(BlockDriverState
*bs
)
7402 BdrvAioNotifier
*baf
, *baf_tmp
;
7404 assert(!bs
->walking_aio_notifiers
);
7405 GLOBAL_STATE_CODE();
7406 bs
->walking_aio_notifiers
= true;
7407 QLIST_FOREACH_SAFE(baf
, &bs
->aio_notifiers
, list
, baf_tmp
) {
7409 bdrv_do_remove_aio_context_notifier(baf
);
7411 baf
->detach_aio_context(baf
->opaque
);
7414 /* Never mind iterating again to check for ->deleted. bdrv_close() will
7415 * remove remaining aio notifiers if we aren't called again.
7417 bs
->walking_aio_notifiers
= false;
7419 if (bs
->drv
&& bs
->drv
->bdrv_detach_aio_context
) {
7420 bs
->drv
->bdrv_detach_aio_context(bs
);
7423 bs
->aio_context
= NULL
;
7426 static void bdrv_attach_aio_context(BlockDriverState
*bs
,
7427 AioContext
*new_context
)
7429 BdrvAioNotifier
*ban
, *ban_tmp
;
7430 GLOBAL_STATE_CODE();
7432 bs
->aio_context
= new_context
;
7434 if (bs
->drv
&& bs
->drv
->bdrv_attach_aio_context
) {
7435 bs
->drv
->bdrv_attach_aio_context(bs
, new_context
);
7438 assert(!bs
->walking_aio_notifiers
);
7439 bs
->walking_aio_notifiers
= true;
7440 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_tmp
) {
7442 bdrv_do_remove_aio_context_notifier(ban
);
7444 ban
->attached_aio_context(new_context
, ban
->opaque
);
7447 bs
->walking_aio_notifiers
= false;
7450 typedef struct BdrvStateSetAioContext
{
7451 AioContext
*new_ctx
;
7452 BlockDriverState
*bs
;
7453 } BdrvStateSetAioContext
;
7455 static bool bdrv_parent_change_aio_context(BdrvChild
*c
, AioContext
*ctx
,
7456 GHashTable
*visited
,
7460 GLOBAL_STATE_CODE();
7461 if (g_hash_table_contains(visited
, c
)) {
7464 g_hash_table_add(visited
, c
);
7467 * A BdrvChildClass that doesn't handle AioContext changes cannot
7468 * tolerate any AioContext changes
7470 if (!c
->klass
->change_aio_ctx
) {
7471 char *user
= bdrv_child_user_desc(c
);
7472 error_setg(errp
, "Changing iothreads is not supported by %s", user
);
7476 if (!c
->klass
->change_aio_ctx(c
, ctx
, visited
, tran
, errp
)) {
7477 assert(!errp
|| *errp
);
7483 bool bdrv_child_change_aio_context(BdrvChild
*c
, AioContext
*ctx
,
7484 GHashTable
*visited
, Transaction
*tran
,
7487 GLOBAL_STATE_CODE();
7488 if (g_hash_table_contains(visited
, c
)) {
7491 g_hash_table_add(visited
, c
);
7492 return bdrv_change_aio_context(c
->bs
, ctx
, visited
, tran
, errp
);
7495 static void bdrv_set_aio_context_clean(void *opaque
)
7497 BdrvStateSetAioContext
*state
= (BdrvStateSetAioContext
*) opaque
;
7498 BlockDriverState
*bs
= (BlockDriverState
*) state
->bs
;
7500 /* Paired with bdrv_drained_begin in bdrv_change_aio_context() */
7501 bdrv_drained_end(bs
);
7506 static void bdrv_set_aio_context_commit(void *opaque
)
7508 BdrvStateSetAioContext
*state
= (BdrvStateSetAioContext
*) opaque
;
7509 BlockDriverState
*bs
= (BlockDriverState
*) state
->bs
;
7510 AioContext
*new_context
= state
->new_ctx
;
7511 AioContext
*old_context
= bdrv_get_aio_context(bs
);
7514 * Take the old AioContex when detaching it from bs.
7515 * At this point, new_context lock is already acquired, and we are now
7516 * also taking old_context. This is safe as long as bdrv_detach_aio_context
7517 * does not call AIO_POLL_WHILE().
7519 if (old_context
!= qemu_get_aio_context()) {
7520 aio_context_acquire(old_context
);
7522 bdrv_detach_aio_context(bs
);
7523 if (old_context
!= qemu_get_aio_context()) {
7524 aio_context_release(old_context
);
7526 bdrv_attach_aio_context(bs
, new_context
);
7529 static TransactionActionDrv set_aio_context
= {
7530 .commit
= bdrv_set_aio_context_commit
,
7531 .clean
= bdrv_set_aio_context_clean
,
7535 * Changes the AioContext used for fd handlers, timers, and BHs by this
7536 * BlockDriverState and all its children and parents.
7538 * Must be called from the main AioContext.
7540 * The caller must own the AioContext lock for the old AioContext of bs, but it
7541 * must not own the AioContext lock for new_context (unless new_context is the
7542 * same as the current context of bs).
7544 * @visited will accumulate all visited BdrvChild objects. The caller is
7545 * responsible for freeing the list afterwards.
7547 static bool bdrv_change_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
7548 GHashTable
*visited
, Transaction
*tran
,
7552 BdrvStateSetAioContext
*state
;
7554 GLOBAL_STATE_CODE();
7556 if (bdrv_get_aio_context(bs
) == ctx
) {
7560 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
7561 if (!bdrv_parent_change_aio_context(c
, ctx
, visited
, tran
, errp
)) {
7566 QLIST_FOREACH(c
, &bs
->children
, next
) {
7567 if (!bdrv_child_change_aio_context(c
, ctx
, visited
, tran
, errp
)) {
7572 state
= g_new(BdrvStateSetAioContext
, 1);
7573 *state
= (BdrvStateSetAioContext
) {
7578 /* Paired with bdrv_drained_end in bdrv_set_aio_context_clean() */
7579 bdrv_drained_begin(bs
);
7581 tran_add(tran
, &set_aio_context
, state
);
7587 * Change bs's and recursively all of its parents' and children's AioContext
7588 * to the given new context, returning an error if that isn't possible.
7590 * If ignore_child is not NULL, that child (and its subgraph) will not
7593 * This function still requires the caller to take the bs current
7594 * AioContext lock, otherwise draining will fail since AIO_WAIT_WHILE
7595 * assumes the lock is always held if bs is in another AioContext.
7596 * For the same reason, it temporarily also holds the new AioContext, since
7597 * bdrv_drained_end calls BDRV_POLL_WHILE that assumes the lock is taken too.
7598 * Therefore the new AioContext lock must not be taken by the caller.
7600 int bdrv_try_change_aio_context(BlockDriverState
*bs
, AioContext
*ctx
,
7601 BdrvChild
*ignore_child
, Error
**errp
)
7604 GHashTable
*visited
;
7606 AioContext
*old_context
= bdrv_get_aio_context(bs
);
7607 GLOBAL_STATE_CODE();
7610 * Recursion phase: go through all nodes of the graph.
7611 * Take care of checking that all nodes support changing AioContext
7612 * and drain them, building a linear list of callbacks to run if everything
7613 * is successful (the transaction itself).
7616 visited
= g_hash_table_new(NULL
, NULL
);
7618 g_hash_table_add(visited
, ignore_child
);
7620 ret
= bdrv_change_aio_context(bs
, ctx
, visited
, tran
, errp
);
7621 g_hash_table_destroy(visited
);
7624 * Linear phase: go through all callbacks collected in the transaction.
7625 * Run all callbacks collected in the recursion to switch all nodes
7626 * AioContext lock (transaction commit), or undo all changes done in the
7627 * recursion (transaction abort).
7631 /* Just run clean() callbacks. No AioContext changed. */
7637 * Release old AioContext, it won't be needed anymore, as all
7638 * bdrv_drained_begin() have been called already.
7640 if (qemu_get_aio_context() != old_context
) {
7641 aio_context_release(old_context
);
7645 * Acquire new AioContext since bdrv_drained_end() is going to be called
7646 * after we switched all nodes in the new AioContext, and the function
7647 * assumes that the lock of the bs is always taken.
7649 if (qemu_get_aio_context() != ctx
) {
7650 aio_context_acquire(ctx
);
7655 if (qemu_get_aio_context() != ctx
) {
7656 aio_context_release(ctx
);
7659 /* Re-acquire the old AioContext, since the caller takes and releases it. */
7660 if (qemu_get_aio_context() != old_context
) {
7661 aio_context_acquire(old_context
);
7667 void bdrv_add_aio_context_notifier(BlockDriverState
*bs
,
7668 void (*attached_aio_context
)(AioContext
*new_context
, void *opaque
),
7669 void (*detach_aio_context
)(void *opaque
), void *opaque
)
7671 BdrvAioNotifier
*ban
= g_new(BdrvAioNotifier
, 1);
7672 *ban
= (BdrvAioNotifier
){
7673 .attached_aio_context
= attached_aio_context
,
7674 .detach_aio_context
= detach_aio_context
,
7677 GLOBAL_STATE_CODE();
7679 QLIST_INSERT_HEAD(&bs
->aio_notifiers
, ban
, list
);
7682 void bdrv_remove_aio_context_notifier(BlockDriverState
*bs
,
7683 void (*attached_aio_context
)(AioContext
*,
7685 void (*detach_aio_context
)(void *),
7688 BdrvAioNotifier
*ban
, *ban_next
;
7689 GLOBAL_STATE_CODE();
7691 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_next
) {
7692 if (ban
->attached_aio_context
== attached_aio_context
&&
7693 ban
->detach_aio_context
== detach_aio_context
&&
7694 ban
->opaque
== opaque
&&
7695 ban
->deleted
== false)
7697 if (bs
->walking_aio_notifiers
) {
7698 ban
->deleted
= true;
7700 bdrv_do_remove_aio_context_notifier(ban
);
7709 int bdrv_amend_options(BlockDriverState
*bs
, QemuOpts
*opts
,
7710 BlockDriverAmendStatusCB
*status_cb
, void *cb_opaque
,
7714 GLOBAL_STATE_CODE();
7716 error_setg(errp
, "Node is ejected");
7719 if (!bs
->drv
->bdrv_amend_options
) {
7720 error_setg(errp
, "Block driver '%s' does not support option amendment",
7721 bs
->drv
->format_name
);
7724 return bs
->drv
->bdrv_amend_options(bs
, opts
, status_cb
,
7725 cb_opaque
, force
, errp
);
7729 * This function checks whether the given @to_replace is allowed to be
7730 * replaced by a node that always shows the same data as @bs. This is
7731 * used for example to verify whether the mirror job can replace
7732 * @to_replace by the target mirrored from @bs.
7733 * To be replaceable, @bs and @to_replace may either be guaranteed to
7734 * always show the same data (because they are only connected through
7735 * filters), or some driver may allow replacing one of its children
7736 * because it can guarantee that this child's data is not visible at
7737 * all (for example, for dissenting quorum children that have no other
7740 bool bdrv_recurse_can_replace(BlockDriverState
*bs
,
7741 BlockDriverState
*to_replace
)
7743 BlockDriverState
*filtered
;
7745 GLOBAL_STATE_CODE();
7747 if (!bs
|| !bs
->drv
) {
7751 if (bs
== to_replace
) {
7755 /* See what the driver can do */
7756 if (bs
->drv
->bdrv_recurse_can_replace
) {
7757 return bs
->drv
->bdrv_recurse_can_replace(bs
, to_replace
);
7760 /* For filters without an own implementation, we can recurse on our own */
7761 filtered
= bdrv_filter_bs(bs
);
7763 return bdrv_recurse_can_replace(filtered
, to_replace
);
7771 * Check whether the given @node_name can be replaced by a node that
7772 * has the same data as @parent_bs. If so, return @node_name's BDS;
7775 * @node_name must be a (recursive) *child of @parent_bs (or this
7776 * function will return NULL).
7778 * The result (whether the node can be replaced or not) is only valid
7779 * for as long as no graph or permission changes occur.
7781 BlockDriverState
*check_to_replace_node(BlockDriverState
*parent_bs
,
7782 const char *node_name
, Error
**errp
)
7784 BlockDriverState
*to_replace_bs
= bdrv_find_node(node_name
);
7785 AioContext
*aio_context
;
7787 GLOBAL_STATE_CODE();
7789 if (!to_replace_bs
) {
7790 error_setg(errp
, "Failed to find node with node-name='%s'", node_name
);
7794 aio_context
= bdrv_get_aio_context(to_replace_bs
);
7795 aio_context_acquire(aio_context
);
7797 if (bdrv_op_is_blocked(to_replace_bs
, BLOCK_OP_TYPE_REPLACE
, errp
)) {
7798 to_replace_bs
= NULL
;
7802 /* We don't want arbitrary node of the BDS chain to be replaced only the top
7803 * most non filter in order to prevent data corruption.
7804 * Another benefit is that this tests exclude backing files which are
7805 * blocked by the backing blockers.
7807 if (!bdrv_recurse_can_replace(parent_bs
, to_replace_bs
)) {
7808 error_setg(errp
, "Cannot replace '%s' by a node mirrored from '%s', "
7809 "because it cannot be guaranteed that doing so would not "
7810 "lead to an abrupt change of visible data",
7811 node_name
, parent_bs
->node_name
);
7812 to_replace_bs
= NULL
;
7817 aio_context_release(aio_context
);
7818 return to_replace_bs
;
7822 * Iterates through the list of runtime option keys that are said to
7823 * be "strong" for a BDS. An option is called "strong" if it changes
7824 * a BDS's data. For example, the null block driver's "size" and
7825 * "read-zeroes" options are strong, but its "latency-ns" option is
7828 * If a key returned by this function ends with a dot, all options
7829 * starting with that prefix are strong.
7831 static const char *const *strong_options(BlockDriverState
*bs
,
7832 const char *const *curopt
)
7834 static const char *const global_options
[] = {
7835 "driver", "filename", NULL
7839 return &global_options
[0];
7843 if (curopt
== &global_options
[ARRAY_SIZE(global_options
) - 1] && bs
->drv
) {
7844 curopt
= bs
->drv
->strong_runtime_opts
;
7847 return (curopt
&& *curopt
) ? curopt
: NULL
;
7851 * Copies all strong runtime options from bs->options to the given
7852 * QDict. The set of strong option keys is determined by invoking
7855 * Returns true iff any strong option was present in bs->options (and
7856 * thus copied to the target QDict) with the exception of "filename"
7857 * and "driver". The caller is expected to use this value to decide
7858 * whether the existence of strong options prevents the generation of
7861 static bool append_strong_runtime_options(QDict
*d
, BlockDriverState
*bs
)
7863 bool found_any
= false;
7864 const char *const *option_name
= NULL
;
7870 while ((option_name
= strong_options(bs
, option_name
))) {
7871 bool option_given
= false;
7873 assert(strlen(*option_name
) > 0);
7874 if ((*option_name
)[strlen(*option_name
) - 1] != '.') {
7875 QObject
*entry
= qdict_get(bs
->options
, *option_name
);
7880 qdict_put_obj(d
, *option_name
, qobject_ref(entry
));
7881 option_given
= true;
7883 const QDictEntry
*entry
;
7884 for (entry
= qdict_first(bs
->options
); entry
;
7885 entry
= qdict_next(bs
->options
, entry
))
7887 if (strstart(qdict_entry_key(entry
), *option_name
, NULL
)) {
7888 qdict_put_obj(d
, qdict_entry_key(entry
),
7889 qobject_ref(qdict_entry_value(entry
)));
7890 option_given
= true;
7895 /* While "driver" and "filename" need to be included in a JSON filename,
7896 * their existence does not prohibit generation of a plain filename. */
7897 if (!found_any
&& option_given
&&
7898 strcmp(*option_name
, "driver") && strcmp(*option_name
, "filename"))
7904 if (!qdict_haskey(d
, "driver")) {
7905 /* Drivers created with bdrv_new_open_driver() may not have a
7906 * @driver option. Add it here. */
7907 qdict_put_str(d
, "driver", bs
->drv
->format_name
);
7913 /* Note: This function may return false positives; it may return true
7914 * even if opening the backing file specified by bs's image header
7915 * would result in exactly bs->backing. */
7916 static bool bdrv_backing_overridden(BlockDriverState
*bs
)
7918 GLOBAL_STATE_CODE();
7920 return strcmp(bs
->auto_backing_file
,
7921 bs
->backing
->bs
->filename
);
7923 /* No backing BDS, so if the image header reports any backing
7924 * file, it must have been suppressed */
7925 return bs
->auto_backing_file
[0] != '\0';
7929 /* Updates the following BDS fields:
7930 * - exact_filename: A filename which may be used for opening a block device
7931 * which (mostly) equals the given BDS (even without any
7932 * other options; so reading and writing must return the same
7933 * results, but caching etc. may be different)
7934 * - full_open_options: Options which, when given when opening a block device
7935 * (without a filename), result in a BDS (mostly)
7936 * equalling the given one
7937 * - filename: If exact_filename is set, it is copied here. Otherwise,
7938 * full_open_options is converted to a JSON object, prefixed with
7939 * "json:" (for use through the JSON pseudo protocol) and put here.
7941 void bdrv_refresh_filename(BlockDriverState
*bs
)
7943 BlockDriver
*drv
= bs
->drv
;
7945 BlockDriverState
*primary_child_bs
;
7947 bool backing_overridden
;
7948 bool generate_json_filename
; /* Whether our default implementation should
7949 fill exact_filename (false) or not (true) */
7951 GLOBAL_STATE_CODE();
7957 /* This BDS's file name may depend on any of its children's file names, so
7958 * refresh those first */
7959 QLIST_FOREACH(child
, &bs
->children
, next
) {
7960 bdrv_refresh_filename(child
->bs
);
7964 /* For implicit nodes, just copy everything from the single child */
7965 child
= QLIST_FIRST(&bs
->children
);
7966 assert(QLIST_NEXT(child
, next
) == NULL
);
7968 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
),
7969 child
->bs
->exact_filename
);
7970 pstrcpy(bs
->filename
, sizeof(bs
->filename
), child
->bs
->filename
);
7972 qobject_unref(bs
->full_open_options
);
7973 bs
->full_open_options
= qobject_ref(child
->bs
->full_open_options
);
7978 backing_overridden
= bdrv_backing_overridden(bs
);
7980 if (bs
->open_flags
& BDRV_O_NO_IO
) {
7981 /* Without I/O, the backing file does not change anything.
7982 * Therefore, in such a case (primarily qemu-img), we can
7983 * pretend the backing file has not been overridden even if
7984 * it technically has been. */
7985 backing_overridden
= false;
7988 /* Gather the options QDict */
7990 generate_json_filename
= append_strong_runtime_options(opts
, bs
);
7991 generate_json_filename
|= backing_overridden
;
7993 if (drv
->bdrv_gather_child_options
) {
7994 /* Some block drivers may not want to present all of their children's
7995 * options, or name them differently from BdrvChild.name */
7996 drv
->bdrv_gather_child_options(bs
, opts
, backing_overridden
);
7998 QLIST_FOREACH(child
, &bs
->children
, next
) {
7999 if (child
== bs
->backing
&& !backing_overridden
) {
8000 /* We can skip the backing BDS if it has not been overridden */
8004 qdict_put(opts
, child
->name
,
8005 qobject_ref(child
->bs
->full_open_options
));
8008 if (backing_overridden
&& !bs
->backing
) {
8009 /* Force no backing file */
8010 qdict_put_null(opts
, "backing");
8014 qobject_unref(bs
->full_open_options
);
8015 bs
->full_open_options
= opts
;
8017 primary_child_bs
= bdrv_primary_bs(bs
);
8019 if (drv
->bdrv_refresh_filename
) {
8020 /* Obsolete information is of no use here, so drop the old file name
8021 * information before refreshing it */
8022 bs
->exact_filename
[0] = '\0';
8024 drv
->bdrv_refresh_filename(bs
);
8025 } else if (primary_child_bs
) {
8027 * Try to reconstruct valid information from the underlying
8028 * file -- this only works for format nodes (filter nodes
8029 * cannot be probed and as such must be selected by the user
8030 * either through an options dict, or through a special
8031 * filename which the filter driver must construct in its
8032 * .bdrv_refresh_filename() implementation).
8035 bs
->exact_filename
[0] = '\0';
8038 * We can use the underlying file's filename if:
8039 * - it has a filename,
8040 * - the current BDS is not a filter,
8041 * - the file is a protocol BDS, and
8042 * - opening that file (as this BDS's format) will automatically create
8043 * the BDS tree we have right now, that is:
8044 * - the user did not significantly change this BDS's behavior with
8045 * some explicit (strong) options
8046 * - no non-file child of this BDS has been overridden by the user
8047 * Both of these conditions are represented by generate_json_filename.
8049 if (primary_child_bs
->exact_filename
[0] &&
8050 primary_child_bs
->drv
->bdrv_file_open
&&
8051 !drv
->is_filter
&& !generate_json_filename
)
8053 strcpy(bs
->exact_filename
, primary_child_bs
->exact_filename
);
8057 if (bs
->exact_filename
[0]) {
8058 pstrcpy(bs
->filename
, sizeof(bs
->filename
), bs
->exact_filename
);
8060 GString
*json
= qobject_to_json(QOBJECT(bs
->full_open_options
));
8061 if (snprintf(bs
->filename
, sizeof(bs
->filename
), "json:%s",
8062 json
->str
) >= sizeof(bs
->filename
)) {
8063 /* Give user a hint if we truncated things. */
8064 strcpy(bs
->filename
+ sizeof(bs
->filename
) - 4, "...");
8066 g_string_free(json
, true);
8070 char *bdrv_dirname(BlockDriverState
*bs
, Error
**errp
)
8072 BlockDriver
*drv
= bs
->drv
;
8073 BlockDriverState
*child_bs
;
8075 GLOBAL_STATE_CODE();
8078 error_setg(errp
, "Node '%s' is ejected", bs
->node_name
);
8082 if (drv
->bdrv_dirname
) {
8083 return drv
->bdrv_dirname(bs
, errp
);
8086 child_bs
= bdrv_primary_bs(bs
);
8088 return bdrv_dirname(child_bs
, errp
);
8091 bdrv_refresh_filename(bs
);
8092 if (bs
->exact_filename
[0] != '\0') {
8093 return path_combine(bs
->exact_filename
, "");
8096 error_setg(errp
, "Cannot generate a base directory for %s nodes",
8102 * Hot add/remove a BDS's child. So the user can take a child offline when
8103 * it is broken and take a new child online
8105 void bdrv_add_child(BlockDriverState
*parent_bs
, BlockDriverState
*child_bs
,
8108 GLOBAL_STATE_CODE();
8109 if (!parent_bs
->drv
|| !parent_bs
->drv
->bdrv_add_child
) {
8110 error_setg(errp
, "The node %s does not support adding a child",
8111 bdrv_get_device_or_node_name(parent_bs
));
8116 * Non-zoned block drivers do not follow zoned storage constraints
8117 * (i.e. sequential writes to zones). Refuse mixing zoned and non-zoned
8118 * drivers in a graph.
8120 if (!parent_bs
->drv
->supports_zoned_children
&&
8121 child_bs
->bl
.zoned
== BLK_Z_HM
) {
8123 * The host-aware model allows zoned storage constraints and random
8124 * write. Allow mixing host-aware and non-zoned drivers. Using
8125 * host-aware device as a regular device.
8127 error_setg(errp
, "Cannot add a %s child to a %s parent",
8128 child_bs
->bl
.zoned
== BLK_Z_HM
? "zoned" : "non-zoned",
8129 parent_bs
->drv
->supports_zoned_children
?
8130 "support zoned children" : "not support zoned children");
8134 if (!QLIST_EMPTY(&child_bs
->parents
)) {
8135 error_setg(errp
, "The node %s already has a parent",
8136 child_bs
->node_name
);
8140 parent_bs
->drv
->bdrv_add_child(parent_bs
, child_bs
, errp
);
8143 void bdrv_del_child(BlockDriverState
*parent_bs
, BdrvChild
*child
, Error
**errp
)
8147 GLOBAL_STATE_CODE();
8148 if (!parent_bs
->drv
|| !parent_bs
->drv
->bdrv_del_child
) {
8149 error_setg(errp
, "The node %s does not support removing a child",
8150 bdrv_get_device_or_node_name(parent_bs
));
8154 QLIST_FOREACH(tmp
, &parent_bs
->children
, next
) {
8161 error_setg(errp
, "The node %s does not have a child named %s",
8162 bdrv_get_device_or_node_name(parent_bs
),
8163 bdrv_get_device_or_node_name(child
->bs
));
8167 parent_bs
->drv
->bdrv_del_child(parent_bs
, child
, errp
);
8170 int bdrv_make_empty(BdrvChild
*c
, Error
**errp
)
8172 BlockDriver
*drv
= c
->bs
->drv
;
8175 GLOBAL_STATE_CODE();
8176 assert(c
->perm
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
));
8178 if (!drv
->bdrv_make_empty
) {
8179 error_setg(errp
, "%s does not support emptying nodes",
8184 ret
= drv
->bdrv_make_empty(c
->bs
);
8186 error_setg_errno(errp
, -ret
, "Failed to empty %s",
8195 * Return the child that @bs acts as an overlay for, and from which data may be
8196 * copied in COW or COR operations. Usually this is the backing file.
8198 BdrvChild
*bdrv_cow_child(BlockDriverState
*bs
)
8202 if (!bs
|| !bs
->drv
) {
8206 if (bs
->drv
->is_filter
) {
8214 assert(bs
->backing
->role
& BDRV_CHILD_COW
);
8219 * If @bs acts as a filter for exactly one of its children, return
8222 BdrvChild
*bdrv_filter_child(BlockDriverState
*bs
)
8227 if (!bs
|| !bs
->drv
) {
8231 if (!bs
->drv
->is_filter
) {
8235 /* Only one of @backing or @file may be used */
8236 assert(!(bs
->backing
&& bs
->file
));
8238 c
= bs
->backing
?: bs
->file
;
8243 assert(c
->role
& BDRV_CHILD_FILTERED
);
8248 * Return either the result of bdrv_cow_child() or bdrv_filter_child(),
8249 * whichever is non-NULL.
8251 * Return NULL if both are NULL.
8253 BdrvChild
*bdrv_filter_or_cow_child(BlockDriverState
*bs
)
8255 BdrvChild
*cow_child
= bdrv_cow_child(bs
);
8256 BdrvChild
*filter_child
= bdrv_filter_child(bs
);
8259 /* Filter nodes cannot have COW backing files */
8260 assert(!(cow_child
&& filter_child
));
8262 return cow_child
?: filter_child
;
8266 * Return the primary child of this node: For filters, that is the
8267 * filtered child. For other nodes, that is usually the child storing
8269 * (A generally more helpful description is that this is (usually) the
8270 * child that has the same filename as @bs.)
8272 * Drivers do not necessarily have a primary child; for example quorum
8275 BdrvChild
*bdrv_primary_child(BlockDriverState
*bs
)
8277 BdrvChild
*c
, *found
= NULL
;
8280 QLIST_FOREACH(c
, &bs
->children
, next
) {
8281 if (c
->role
& BDRV_CHILD_PRIMARY
) {
8290 static BlockDriverState
*bdrv_do_skip_filters(BlockDriverState
*bs
,
8291 bool stop_on_explicit_filter
)
8299 while (!(stop_on_explicit_filter
&& !bs
->implicit
)) {
8300 c
= bdrv_filter_child(bs
);
8303 * A filter that is embedded in a working block graph must
8304 * have a child. Assert this here so this function does
8305 * not return a filter node that is not expected by the
8308 assert(!bs
->drv
|| !bs
->drv
->is_filter
);
8314 * Note that this treats nodes with bs->drv == NULL as not being
8315 * filters (bs->drv == NULL should be replaced by something else
8317 * The advantage of this behavior is that this function will thus
8318 * always return a non-NULL value (given a non-NULL @bs).
8325 * Return the first BDS that has not been added implicitly or that
8326 * does not have a filtered child down the chain starting from @bs
8327 * (including @bs itself).
8329 BlockDriverState
*bdrv_skip_implicit_filters(BlockDriverState
*bs
)
8331 GLOBAL_STATE_CODE();
8332 return bdrv_do_skip_filters(bs
, true);
8336 * Return the first BDS that does not have a filtered child down the
8337 * chain starting from @bs (including @bs itself).
8339 BlockDriverState
*bdrv_skip_filters(BlockDriverState
*bs
)
8342 return bdrv_do_skip_filters(bs
, false);
8346 * For a backing chain, return the first non-filter backing image of
8347 * the first non-filter image.
8349 BlockDriverState
*bdrv_backing_chain_next(BlockDriverState
*bs
)
8352 return bdrv_skip_filters(bdrv_cow_bs(bdrv_skip_filters(bs
)));
8356 * Check whether [offset, offset + bytes) overlaps with the cached
8357 * block-status data region.
8359 * If so, and @pnum is not NULL, set *pnum to `bsc.data_end - offset`,
8360 * which is what bdrv_bsc_is_data()'s interface needs.
8361 * Otherwise, *pnum is not touched.
8363 static bool bdrv_bsc_range_overlaps_locked(BlockDriverState
*bs
,
8364 int64_t offset
, int64_t bytes
,
8367 BdrvBlockStatusCache
*bsc
= qatomic_rcu_read(&bs
->block_status_cache
);
8371 qatomic_read(&bsc
->valid
) &&
8372 ranges_overlap(offset
, bytes
, bsc
->data_start
,
8373 bsc
->data_end
- bsc
->data_start
);
8375 if (overlaps
&& pnum
) {
8376 *pnum
= bsc
->data_end
- offset
;
8383 * See block_int.h for this function's documentation.
8385 bool bdrv_bsc_is_data(BlockDriverState
*bs
, int64_t offset
, int64_t *pnum
)
8388 RCU_READ_LOCK_GUARD();
8389 return bdrv_bsc_range_overlaps_locked(bs
, offset
, 1, pnum
);
8393 * See block_int.h for this function's documentation.
8395 void bdrv_bsc_invalidate_range(BlockDriverState
*bs
,
8396 int64_t offset
, int64_t bytes
)
8399 RCU_READ_LOCK_GUARD();
8401 if (bdrv_bsc_range_overlaps_locked(bs
, offset
, bytes
, NULL
)) {
8402 qatomic_set(&bs
->block_status_cache
->valid
, false);
8407 * See block_int.h for this function's documentation.
8409 void bdrv_bsc_fill(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
)
8411 BdrvBlockStatusCache
*new_bsc
= g_new(BdrvBlockStatusCache
, 1);
8412 BdrvBlockStatusCache
*old_bsc
;
8415 *new_bsc
= (BdrvBlockStatusCache
) {
8417 .data_start
= offset
,
8418 .data_end
= offset
+ bytes
,
8421 QEMU_LOCK_GUARD(&bs
->bsc_modify_lock
);
8423 old_bsc
= qatomic_rcu_read(&bs
->block_status_cache
);
8424 qatomic_rcu_set(&bs
->block_status_cache
, new_bsc
);
8426 g_free_rcu(old_bsc
, rcu
);