2 * QEMU System Emulator block driver
4 * Copyright (c) 2003 Fabrice Bellard
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24 #include "qemu/osdep.h"
25 #include "block/trace.h"
26 #include "block/block_int.h"
27 #include "block/blockjob.h"
28 #include "block/nbd.h"
29 #include "qemu/error-report.h"
30 #include "module_block.h"
31 #include "qemu/module.h"
32 #include "qapi/qmp/qerror.h"
33 #include "qapi/qmp/qbool.h"
34 #include "qapi/qmp/qjson.h"
35 #include "sysemu/block-backend.h"
36 #include "sysemu/sysemu.h"
37 #include "qemu/notify.h"
38 #include "qemu/coroutine.h"
39 #include "block/qapi.h"
40 #include "qmp-commands.h"
41 #include "qemu/timer.h"
42 #include "qapi-event.h"
43 #include "qemu/cutils.h"
45 #include "qapi/util.h"
48 #include <sys/ioctl.h>
49 #include <sys/queue.h>
59 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
61 static QTAILQ_HEAD(, BlockDriverState
) graph_bdrv_states
=
62 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states
);
64 static QTAILQ_HEAD(, BlockDriverState
) all_bdrv_states
=
65 QTAILQ_HEAD_INITIALIZER(all_bdrv_states
);
67 static QLIST_HEAD(, BlockDriver
) bdrv_drivers
=
68 QLIST_HEAD_INITIALIZER(bdrv_drivers
);
70 static BlockDriverState
*bdrv_open_inherit(const char *filename
,
71 const char *reference
,
72 QDict
*options
, int flags
,
73 BlockDriverState
*parent
,
74 const BdrvChildRole
*child_role
,
77 /* If non-zero, use only whitelisted block drivers */
78 static int use_bdrv_whitelist
;
81 static int is_windows_drive_prefix(const char *filename
)
83 return (((filename
[0] >= 'a' && filename
[0] <= 'z') ||
84 (filename
[0] >= 'A' && filename
[0] <= 'Z')) &&
88 int is_windows_drive(const char *filename
)
90 if (is_windows_drive_prefix(filename
) &&
93 if (strstart(filename
, "\\\\.\\", NULL
) ||
94 strstart(filename
, "//./", NULL
))
100 size_t bdrv_opt_mem_align(BlockDriverState
*bs
)
102 if (!bs
|| !bs
->drv
) {
103 /* page size or 4k (hdd sector size) should be on the safe side */
104 return MAX(4096, getpagesize());
107 return bs
->bl
.opt_mem_alignment
;
110 size_t bdrv_min_mem_align(BlockDriverState
*bs
)
112 if (!bs
|| !bs
->drv
) {
113 /* page size or 4k (hdd sector size) should be on the safe side */
114 return MAX(4096, getpagesize());
117 return bs
->bl
.min_mem_alignment
;
120 /* check if the path starts with "<protocol>:" */
121 int path_has_protocol(const char *path
)
126 if (is_windows_drive(path
) ||
127 is_windows_drive_prefix(path
)) {
130 p
= path
+ strcspn(path
, ":/\\");
132 p
= path
+ strcspn(path
, ":/");
138 int path_is_absolute(const char *path
)
141 /* specific case for names like: "\\.\d:" */
142 if (is_windows_drive(path
) || is_windows_drive_prefix(path
)) {
145 return (*path
== '/' || *path
== '\\');
147 return (*path
== '/');
151 /* if filename is absolute, just copy it to dest. Otherwise, build a
152 path to it by considering it is relative to base_path. URL are
154 void path_combine(char *dest
, int dest_size
,
155 const char *base_path
,
156 const char *filename
)
163 if (path_is_absolute(filename
)) {
164 pstrcpy(dest
, dest_size
, filename
);
166 p
= strchr(base_path
, ':');
171 p1
= strrchr(base_path
, '/');
175 p2
= strrchr(base_path
, '\\');
187 if (len
> dest_size
- 1)
189 memcpy(dest
, base_path
, len
);
191 pstrcat(dest
, dest_size
, filename
);
195 void bdrv_get_full_backing_filename_from_filename(const char *backed
,
197 char *dest
, size_t sz
,
200 if (backing
[0] == '\0' || path_has_protocol(backing
) ||
201 path_is_absolute(backing
))
203 pstrcpy(dest
, sz
, backing
);
204 } else if (backed
[0] == '\0' || strstart(backed
, "json:", NULL
)) {
205 error_setg(errp
, "Cannot use relative backing file names for '%s'",
208 path_combine(dest
, sz
, backed
, backing
);
212 void bdrv_get_full_backing_filename(BlockDriverState
*bs
, char *dest
, size_t sz
,
215 char *backed
= bs
->exact_filename
[0] ? bs
->exact_filename
: bs
->filename
;
217 bdrv_get_full_backing_filename_from_filename(backed
, bs
->backing_file
,
221 void bdrv_register(BlockDriver
*bdrv
)
223 QLIST_INSERT_HEAD(&bdrv_drivers
, bdrv
, list
);
226 BlockDriverState
*bdrv_new(void)
228 BlockDriverState
*bs
;
231 bs
= g_new0(BlockDriverState
, 1);
232 QLIST_INIT(&bs
->dirty_bitmaps
);
233 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
234 QLIST_INIT(&bs
->op_blockers
[i
]);
236 notifier_with_return_list_init(&bs
->before_write_notifiers
);
238 bs
->aio_context
= qemu_get_aio_context();
240 qemu_co_queue_init(&bs
->flush_queue
);
242 QTAILQ_INSERT_TAIL(&all_bdrv_states
, bs
, bs_list
);
247 static BlockDriver
*bdrv_do_find_format(const char *format_name
)
251 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
252 if (!strcmp(drv1
->format_name
, format_name
)) {
260 BlockDriver
*bdrv_find_format(const char *format_name
)
265 drv1
= bdrv_do_find_format(format_name
);
270 /* The driver isn't registered, maybe we need to load a module */
271 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
272 if (!strcmp(block_driver_modules
[i
].format_name
, format_name
)) {
273 block_module_load_one(block_driver_modules
[i
].library_name
);
278 return bdrv_do_find_format(format_name
);
281 static int bdrv_is_whitelisted(BlockDriver
*drv
, bool read_only
)
283 static const char *whitelist_rw
[] = {
284 CONFIG_BDRV_RW_WHITELIST
286 static const char *whitelist_ro
[] = {
287 CONFIG_BDRV_RO_WHITELIST
291 if (!whitelist_rw
[0] && !whitelist_ro
[0]) {
292 return 1; /* no whitelist, anything goes */
295 for (p
= whitelist_rw
; *p
; p
++) {
296 if (!strcmp(drv
->format_name
, *p
)) {
301 for (p
= whitelist_ro
; *p
; p
++) {
302 if (!strcmp(drv
->format_name
, *p
)) {
310 bool bdrv_uses_whitelist(void)
312 return use_bdrv_whitelist
;
315 typedef struct CreateCo
{
323 static void coroutine_fn
bdrv_create_co_entry(void *opaque
)
325 Error
*local_err
= NULL
;
328 CreateCo
*cco
= opaque
;
331 ret
= cco
->drv
->bdrv_create(cco
->filename
, cco
->opts
, &local_err
);
332 error_propagate(&cco
->err
, local_err
);
336 int bdrv_create(BlockDriver
*drv
, const char* filename
,
337 QemuOpts
*opts
, Error
**errp
)
344 .filename
= g_strdup(filename
),
350 if (!drv
->bdrv_create
) {
351 error_setg(errp
, "Driver '%s' does not support image creation", drv
->format_name
);
356 if (qemu_in_coroutine()) {
357 /* Fast-path if already in coroutine context */
358 bdrv_create_co_entry(&cco
);
360 co
= qemu_coroutine_create(bdrv_create_co_entry
, &cco
);
361 qemu_coroutine_enter(co
);
362 while (cco
.ret
== NOT_DONE
) {
363 aio_poll(qemu_get_aio_context(), true);
370 error_propagate(errp
, cco
.err
);
372 error_setg_errno(errp
, -ret
, "Could not create image");
377 g_free(cco
.filename
);
381 int bdrv_create_file(const char *filename
, QemuOpts
*opts
, Error
**errp
)
384 Error
*local_err
= NULL
;
387 drv
= bdrv_find_protocol(filename
, true, errp
);
392 ret
= bdrv_create(drv
, filename
, opts
, &local_err
);
393 error_propagate(errp
, local_err
);
398 * Try to get @bs's logical and physical block size.
399 * On success, store them in @bsz struct and return 0.
400 * On failure return -errno.
401 * @bs must not be empty.
403 int bdrv_probe_blocksizes(BlockDriverState
*bs
, BlockSizes
*bsz
)
405 BlockDriver
*drv
= bs
->drv
;
407 if (drv
&& drv
->bdrv_probe_blocksizes
) {
408 return drv
->bdrv_probe_blocksizes(bs
, bsz
);
415 * Try to get @bs's geometry (cyls, heads, sectors).
416 * On success, store them in @geo struct and return 0.
417 * On failure return -errno.
418 * @bs must not be empty.
420 int bdrv_probe_geometry(BlockDriverState
*bs
, HDGeometry
*geo
)
422 BlockDriver
*drv
= bs
->drv
;
424 if (drv
&& drv
->bdrv_probe_geometry
) {
425 return drv
->bdrv_probe_geometry(bs
, geo
);
432 * Create a uniquely-named empty temporary file.
433 * Return 0 upon success, otherwise a negative errno value.
435 int get_tmp_filename(char *filename
, int size
)
438 char temp_dir
[MAX_PATH
];
439 /* GetTempFileName requires that its output buffer (4th param)
440 have length MAX_PATH or greater. */
441 assert(size
>= MAX_PATH
);
442 return (GetTempPath(MAX_PATH
, temp_dir
)
443 && GetTempFileName(temp_dir
, "qem", 0, filename
)
444 ? 0 : -GetLastError());
448 tmpdir
= getenv("TMPDIR");
452 if (snprintf(filename
, size
, "%s/vl.XXXXXX", tmpdir
) >= size
) {
455 fd
= mkstemp(filename
);
459 if (close(fd
) != 0) {
468 * Detect host devices. By convention, /dev/cdrom[N] is always
469 * recognized as a host CDROM.
471 static BlockDriver
*find_hdev_driver(const char *filename
)
473 int score_max
= 0, score
;
474 BlockDriver
*drv
= NULL
, *d
;
476 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
477 if (d
->bdrv_probe_device
) {
478 score
= d
->bdrv_probe_device(filename
);
479 if (score
> score_max
) {
489 static BlockDriver
*bdrv_do_find_protocol(const char *protocol
)
493 QLIST_FOREACH(drv1
, &bdrv_drivers
, list
) {
494 if (drv1
->protocol_name
&& !strcmp(drv1
->protocol_name
, protocol
)) {
502 BlockDriver
*bdrv_find_protocol(const char *filename
,
503 bool allow_protocol_prefix
,
512 /* TODO Drivers without bdrv_file_open must be specified explicitly */
515 * XXX(hch): we really should not let host device detection
516 * override an explicit protocol specification, but moving this
517 * later breaks access to device names with colons in them.
518 * Thanks to the brain-dead persistent naming schemes on udev-
519 * based Linux systems those actually are quite common.
521 drv1
= find_hdev_driver(filename
);
526 if (!path_has_protocol(filename
) || !allow_protocol_prefix
) {
530 p
= strchr(filename
, ':');
533 if (len
> sizeof(protocol
) - 1)
534 len
= sizeof(protocol
) - 1;
535 memcpy(protocol
, filename
, len
);
536 protocol
[len
] = '\0';
538 drv1
= bdrv_do_find_protocol(protocol
);
543 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); ++i
) {
544 if (block_driver_modules
[i
].protocol_name
&&
545 !strcmp(block_driver_modules
[i
].protocol_name
, protocol
)) {
546 block_module_load_one(block_driver_modules
[i
].library_name
);
551 drv1
= bdrv_do_find_protocol(protocol
);
553 error_setg(errp
, "Unknown protocol '%s'", protocol
);
559 * Guess image format by probing its contents.
560 * This is not a good idea when your image is raw (CVE-2008-2004), but
561 * we do it anyway for backward compatibility.
563 * @buf contains the image's first @buf_size bytes.
564 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
565 * but can be smaller if the image file is smaller)
566 * @filename is its filename.
568 * For all block drivers, call the bdrv_probe() method to get its
570 * Return the first block driver with the highest probing score.
572 BlockDriver
*bdrv_probe_all(const uint8_t *buf
, int buf_size
,
573 const char *filename
)
575 int score_max
= 0, score
;
576 BlockDriver
*drv
= NULL
, *d
;
578 QLIST_FOREACH(d
, &bdrv_drivers
, list
) {
580 score
= d
->bdrv_probe(buf
, buf_size
, filename
);
581 if (score
> score_max
) {
591 static int find_image_format(BlockBackend
*file
, const char *filename
,
592 BlockDriver
**pdrv
, Error
**errp
)
595 uint8_t buf
[BLOCK_PROBE_BUF_SIZE
];
598 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
599 if (blk_is_sg(file
) || !blk_is_inserted(file
) || blk_getlength(file
) == 0) {
604 ret
= blk_pread(file
, 0, buf
, sizeof(buf
));
606 error_setg_errno(errp
, -ret
, "Could not read image for determining its "
612 drv
= bdrv_probe_all(buf
, ret
, filename
);
614 error_setg(errp
, "Could not determine image format: No compatible "
623 * Set the current 'total_sectors' value
624 * Return 0 on success, -errno on error.
626 static int refresh_total_sectors(BlockDriverState
*bs
, int64_t hint
)
628 BlockDriver
*drv
= bs
->drv
;
630 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
634 /* query actual device if possible, otherwise just trust the hint */
635 if (drv
->bdrv_getlength
) {
636 int64_t length
= drv
->bdrv_getlength(bs
);
640 hint
= DIV_ROUND_UP(length
, BDRV_SECTOR_SIZE
);
643 bs
->total_sectors
= hint
;
648 * Combines a QDict of new block driver @options with any missing options taken
649 * from @old_options, so that leaving out an option defaults to its old value.
651 static void bdrv_join_options(BlockDriverState
*bs
, QDict
*options
,
654 if (bs
->drv
&& bs
->drv
->bdrv_join_options
) {
655 bs
->drv
->bdrv_join_options(options
, old_options
);
657 qdict_join(options
, old_options
, false);
662 * Set open flags for a given discard mode
664 * Return 0 on success, -1 if the discard mode was invalid.
666 int bdrv_parse_discard_flags(const char *mode
, int *flags
)
668 *flags
&= ~BDRV_O_UNMAP
;
670 if (!strcmp(mode
, "off") || !strcmp(mode
, "ignore")) {
672 } else if (!strcmp(mode
, "on") || !strcmp(mode
, "unmap")) {
673 *flags
|= BDRV_O_UNMAP
;
682 * Set open flags for a given cache mode
684 * Return 0 on success, -1 if the cache mode was invalid.
686 int bdrv_parse_cache_mode(const char *mode
, int *flags
, bool *writethrough
)
688 *flags
&= ~BDRV_O_CACHE_MASK
;
690 if (!strcmp(mode
, "off") || !strcmp(mode
, "none")) {
691 *writethrough
= false;
692 *flags
|= BDRV_O_NOCACHE
;
693 } else if (!strcmp(mode
, "directsync")) {
694 *writethrough
= true;
695 *flags
|= BDRV_O_NOCACHE
;
696 } else if (!strcmp(mode
, "writeback")) {
697 *writethrough
= false;
698 } else if (!strcmp(mode
, "unsafe")) {
699 *writethrough
= false;
700 *flags
|= BDRV_O_NO_FLUSH
;
701 } else if (!strcmp(mode
, "writethrough")) {
702 *writethrough
= true;
710 static void bdrv_child_cb_drained_begin(BdrvChild
*child
)
712 BlockDriverState
*bs
= child
->opaque
;
713 bdrv_drained_begin(bs
);
716 static void bdrv_child_cb_drained_end(BdrvChild
*child
)
718 BlockDriverState
*bs
= child
->opaque
;
719 bdrv_drained_end(bs
);
723 * Returns the options and flags that a temporary snapshot should get, based on
724 * the originally requested flags (the originally requested image will have
725 * flags like a backing file)
727 static void bdrv_temp_snapshot_options(int *child_flags
, QDict
*child_options
,
728 int parent_flags
, QDict
*parent_options
)
730 *child_flags
= (parent_flags
& ~BDRV_O_SNAPSHOT
) | BDRV_O_TEMPORARY
;
732 /* For temporary files, unconditional cache=unsafe is fine */
733 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_DIRECT
, "off");
734 qdict_set_default_str(child_options
, BDRV_OPT_CACHE_NO_FLUSH
, "on");
736 /* Copy the read-only option from the parent */
737 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
739 /* aio=native doesn't work for cache.direct=off, so disable it for the
740 * temporary snapshot */
741 *child_flags
&= ~BDRV_O_NATIVE_AIO
;
745 * Returns the options and flags that bs->file should get if a protocol driver
746 * is expected, based on the given options and flags for the parent BDS
748 static void bdrv_inherited_options(int *child_flags
, QDict
*child_options
,
749 int parent_flags
, QDict
*parent_options
)
751 int flags
= parent_flags
;
753 /* Enable protocol handling, disable format probing for bs->file */
754 flags
|= BDRV_O_PROTOCOL
;
756 /* If the cache mode isn't explicitly set, inherit direct and no-flush from
758 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_DIRECT
);
759 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_NO_FLUSH
);
761 /* Inherit the read-only option from the parent if it's not set */
762 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_READ_ONLY
);
764 /* Our block drivers take care to send flushes and respect unmap policy,
765 * so we can default to enable both on lower layers regardless of the
766 * corresponding parent options. */
767 qdict_set_default_str(child_options
, BDRV_OPT_DISCARD
, "unmap");
769 /* Clear flags that only apply to the top layer */
770 flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_COPY_ON_READ
|
773 *child_flags
= flags
;
776 const BdrvChildRole child_file
= {
777 .inherit_options
= bdrv_inherited_options
,
778 .drained_begin
= bdrv_child_cb_drained_begin
,
779 .drained_end
= bdrv_child_cb_drained_end
,
783 * Returns the options and flags that bs->file should get if the use of formats
784 * (and not only protocols) is permitted for it, based on the given options and
785 * flags for the parent BDS
787 static void bdrv_inherited_fmt_options(int *child_flags
, QDict
*child_options
,
788 int parent_flags
, QDict
*parent_options
)
790 child_file
.inherit_options(child_flags
, child_options
,
791 parent_flags
, parent_options
);
793 *child_flags
&= ~(BDRV_O_PROTOCOL
| BDRV_O_NO_IO
);
796 const BdrvChildRole child_format
= {
797 .inherit_options
= bdrv_inherited_fmt_options
,
798 .drained_begin
= bdrv_child_cb_drained_begin
,
799 .drained_end
= bdrv_child_cb_drained_end
,
803 * Returns the options and flags that bs->backing should get, based on the
804 * given options and flags for the parent BDS
806 static void bdrv_backing_options(int *child_flags
, QDict
*child_options
,
807 int parent_flags
, QDict
*parent_options
)
809 int flags
= parent_flags
;
811 /* The cache mode is inherited unmodified for backing files; except WCE,
812 * which is only applied on the top level (BlockBackend) */
813 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_DIRECT
);
814 qdict_copy_default(child_options
, parent_options
, BDRV_OPT_CACHE_NO_FLUSH
);
816 /* backing files always opened read-only */
817 qdict_set_default_str(child_options
, BDRV_OPT_READ_ONLY
, "on");
818 flags
&= ~BDRV_O_COPY_ON_READ
;
820 /* snapshot=on is handled on the top layer */
821 flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_TEMPORARY
);
823 *child_flags
= flags
;
826 static const BdrvChildRole child_backing
= {
827 .inherit_options
= bdrv_backing_options
,
828 .drained_begin
= bdrv_child_cb_drained_begin
,
829 .drained_end
= bdrv_child_cb_drained_end
,
832 static int bdrv_open_flags(BlockDriverState
*bs
, int flags
)
834 int open_flags
= flags
;
837 * Clear flags that are internal to the block layer before opening the
840 open_flags
&= ~(BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
| BDRV_O_PROTOCOL
);
843 * Snapshots should be writable.
845 if (flags
& BDRV_O_TEMPORARY
) {
846 open_flags
|= BDRV_O_RDWR
;
852 static void update_flags_from_options(int *flags
, QemuOpts
*opts
)
854 *flags
&= ~BDRV_O_CACHE_MASK
;
856 assert(qemu_opt_find(opts
, BDRV_OPT_CACHE_NO_FLUSH
));
857 if (qemu_opt_get_bool(opts
, BDRV_OPT_CACHE_NO_FLUSH
, false)) {
858 *flags
|= BDRV_O_NO_FLUSH
;
861 assert(qemu_opt_find(opts
, BDRV_OPT_CACHE_DIRECT
));
862 if (qemu_opt_get_bool(opts
, BDRV_OPT_CACHE_DIRECT
, false)) {
863 *flags
|= BDRV_O_NOCACHE
;
866 *flags
&= ~BDRV_O_RDWR
;
868 assert(qemu_opt_find(opts
, BDRV_OPT_READ_ONLY
));
869 if (!qemu_opt_get_bool(opts
, BDRV_OPT_READ_ONLY
, false)) {
870 *flags
|= BDRV_O_RDWR
;
875 static void update_options_from_flags(QDict
*options
, int flags
)
877 if (!qdict_haskey(options
, BDRV_OPT_CACHE_DIRECT
)) {
878 qdict_put(options
, BDRV_OPT_CACHE_DIRECT
,
879 qbool_from_bool(flags
& BDRV_O_NOCACHE
));
881 if (!qdict_haskey(options
, BDRV_OPT_CACHE_NO_FLUSH
)) {
882 qdict_put(options
, BDRV_OPT_CACHE_NO_FLUSH
,
883 qbool_from_bool(flags
& BDRV_O_NO_FLUSH
));
885 if (!qdict_haskey(options
, BDRV_OPT_READ_ONLY
)) {
886 qdict_put(options
, BDRV_OPT_READ_ONLY
,
887 qbool_from_bool(!(flags
& BDRV_O_RDWR
)));
891 static void bdrv_assign_node_name(BlockDriverState
*bs
,
892 const char *node_name
,
895 char *gen_node_name
= NULL
;
898 node_name
= gen_node_name
= id_generate(ID_BLOCK
);
899 } else if (!id_wellformed(node_name
)) {
901 * Check for empty string or invalid characters, but not if it is
902 * generated (generated names use characters not available to the user)
904 error_setg(errp
, "Invalid node name");
908 /* takes care of avoiding namespaces collisions */
909 if (blk_by_name(node_name
)) {
910 error_setg(errp
, "node-name=%s is conflicting with a device id",
915 /* takes care of avoiding duplicates node names */
916 if (bdrv_find_node(node_name
)) {
917 error_setg(errp
, "Duplicate node name");
921 /* copy node name into the bs and insert it into the graph list */
922 pstrcpy(bs
->node_name
, sizeof(bs
->node_name
), node_name
);
923 QTAILQ_INSERT_TAIL(&graph_bdrv_states
, bs
, node_list
);
925 g_free(gen_node_name
);
928 static int bdrv_open_driver(BlockDriverState
*bs
, BlockDriver
*drv
,
929 const char *node_name
, QDict
*options
,
930 int open_flags
, Error
**errp
)
932 Error
*local_err
= NULL
;
935 bdrv_assign_node_name(bs
, node_name
, &local_err
);
937 error_propagate(errp
, local_err
);
942 bs
->opaque
= g_malloc0(drv
->instance_size
);
944 if (drv
->bdrv_file_open
) {
945 assert(!drv
->bdrv_needs_filename
|| bs
->filename
[0]);
946 ret
= drv
->bdrv_file_open(bs
, options
, open_flags
, &local_err
);
948 ret
= drv
->bdrv_open(bs
, options
, open_flags
, &local_err
);
953 error_propagate(errp
, local_err
);
954 } else if (bs
->filename
[0]) {
955 error_setg_errno(errp
, -ret
, "Could not open '%s'", bs
->filename
);
957 error_setg_errno(errp
, -ret
, "Could not open image");
962 ret
= refresh_total_sectors(bs
, bs
->total_sectors
);
964 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
968 bdrv_refresh_limits(bs
, &local_err
);
970 error_propagate(errp
, local_err
);
975 assert(bdrv_opt_mem_align(bs
) != 0);
976 assert(bdrv_min_mem_align(bs
) != 0);
977 assert(is_power_of_2(bs
->bl
.request_alignment
));
982 /* FIXME Close bs first if already opened*/
989 QemuOptsList bdrv_runtime_opts
= {
990 .name
= "bdrv_common",
991 .head
= QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts
.head
),
995 .type
= QEMU_OPT_STRING
,
996 .help
= "Node name of the block device node",
1000 .type
= QEMU_OPT_STRING
,
1001 .help
= "Block driver to use for the node",
1004 .name
= BDRV_OPT_CACHE_DIRECT
,
1005 .type
= QEMU_OPT_BOOL
,
1006 .help
= "Bypass software writeback cache on the host",
1009 .name
= BDRV_OPT_CACHE_NO_FLUSH
,
1010 .type
= QEMU_OPT_BOOL
,
1011 .help
= "Ignore flush requests",
1014 .name
= BDRV_OPT_READ_ONLY
,
1015 .type
= QEMU_OPT_BOOL
,
1016 .help
= "Node is opened in read-only mode",
1019 .name
= "detect-zeroes",
1020 .type
= QEMU_OPT_STRING
,
1021 .help
= "try to optimize zero writes (off, on, unmap)",
1025 .type
= QEMU_OPT_STRING
,
1026 .help
= "discard operation (ignore/off, unmap/on)",
1028 { /* end of list */ }
1033 * Common part for opening disk images and files
1035 * Removes all processed options from *options.
1037 static int bdrv_open_common(BlockDriverState
*bs
, BlockBackend
*file
,
1038 QDict
*options
, Error
**errp
)
1040 int ret
, open_flags
;
1041 const char *filename
;
1042 const char *driver_name
= NULL
;
1043 const char *node_name
= NULL
;
1044 const char *discard
;
1045 const char *detect_zeroes
;
1048 Error
*local_err
= NULL
;
1050 assert(bs
->file
== NULL
);
1051 assert(options
!= NULL
&& bs
->options
!= options
);
1053 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
1054 qemu_opts_absorb_qdict(opts
, options
, &local_err
);
1056 error_propagate(errp
, local_err
);
1061 update_flags_from_options(&bs
->open_flags
, opts
);
1063 driver_name
= qemu_opt_get(opts
, "driver");
1064 drv
= bdrv_find_format(driver_name
);
1065 assert(drv
!= NULL
);
1068 filename
= blk_bs(file
)->filename
;
1070 filename
= qdict_get_try_str(options
, "filename");
1073 if (drv
->bdrv_needs_filename
&& !filename
) {
1074 error_setg(errp
, "The '%s' block driver requires a file name",
1080 trace_bdrv_open_common(bs
, filename
?: "", bs
->open_flags
,
1083 bs
->read_only
= !(bs
->open_flags
& BDRV_O_RDWR
);
1085 if (use_bdrv_whitelist
&& !bdrv_is_whitelisted(drv
, bs
->read_only
)) {
1087 !bs
->read_only
&& bdrv_is_whitelisted(drv
, true)
1088 ? "Driver '%s' can only be used for read-only devices"
1089 : "Driver '%s' is not whitelisted",
1095 assert(bs
->copy_on_read
== 0); /* bdrv_new() and bdrv_close() make it so */
1096 if (bs
->open_flags
& BDRV_O_COPY_ON_READ
) {
1097 if (!bs
->read_only
) {
1098 bdrv_enable_copy_on_read(bs
);
1100 error_setg(errp
, "Can't use copy-on-read on read-only device");
1106 discard
= qemu_opt_get(opts
, "discard");
1107 if (discard
!= NULL
) {
1108 if (bdrv_parse_discard_flags(discard
, &bs
->open_flags
) != 0) {
1109 error_setg(errp
, "Invalid discard option");
1115 detect_zeroes
= qemu_opt_get(opts
, "detect-zeroes");
1116 if (detect_zeroes
) {
1117 BlockdevDetectZeroesOptions value
=
1118 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup
,
1120 BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX
,
1121 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF
,
1124 error_propagate(errp
, local_err
);
1129 if (value
== BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP
&&
1130 !(bs
->open_flags
& BDRV_O_UNMAP
))
1132 error_setg(errp
, "setting detect-zeroes to unmap is not allowed "
1133 "without setting discard operation to unmap");
1138 bs
->detect_zeroes
= value
;
1141 if (filename
!= NULL
) {
1142 pstrcpy(bs
->filename
, sizeof(bs
->filename
), filename
);
1144 bs
->filename
[0] = '\0';
1146 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
), bs
->filename
);
1148 /* Open the image, either directly or using a protocol */
1149 open_flags
= bdrv_open_flags(bs
, bs
->open_flags
);
1150 node_name
= qemu_opt_get(opts
, "node-name");
1152 assert(!drv
->bdrv_file_open
|| file
== NULL
);
1153 ret
= bdrv_open_driver(bs
, drv
, node_name
, options
, open_flags
, errp
);
1158 qemu_opts_del(opts
);
1162 qemu_opts_del(opts
);
1166 static QDict
*parse_json_filename(const char *filename
, Error
**errp
)
1168 QObject
*options_obj
;
1172 ret
= strstart(filename
, "json:", &filename
);
1175 options_obj
= qobject_from_json(filename
);
1177 error_setg(errp
, "Could not parse the JSON options");
1181 if (qobject_type(options_obj
) != QTYPE_QDICT
) {
1182 qobject_decref(options_obj
);
1183 error_setg(errp
, "Invalid JSON object given");
1187 options
= qobject_to_qdict(options_obj
);
1188 qdict_flatten(options
);
1193 static void parse_json_protocol(QDict
*options
, const char **pfilename
,
1196 QDict
*json_options
;
1197 Error
*local_err
= NULL
;
1199 /* Parse json: pseudo-protocol */
1200 if (!*pfilename
|| !g_str_has_prefix(*pfilename
, "json:")) {
1204 json_options
= parse_json_filename(*pfilename
, &local_err
);
1206 error_propagate(errp
, local_err
);
1210 /* Options given in the filename have lower priority than options
1211 * specified directly */
1212 qdict_join(options
, json_options
, false);
1213 QDECREF(json_options
);
1218 * Fills in default options for opening images and converts the legacy
1219 * filename/flags pair to option QDict entries.
1220 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a
1221 * block driver has been specified explicitly.
1223 static int bdrv_fill_options(QDict
**options
, const char *filename
,
1224 int *flags
, Error
**errp
)
1226 const char *drvname
;
1227 bool protocol
= *flags
& BDRV_O_PROTOCOL
;
1228 bool parse_filename
= false;
1229 BlockDriver
*drv
= NULL
;
1230 Error
*local_err
= NULL
;
1232 drvname
= qdict_get_try_str(*options
, "driver");
1234 drv
= bdrv_find_format(drvname
);
1236 error_setg(errp
, "Unknown driver '%s'", drvname
);
1239 /* If the user has explicitly specified the driver, this choice should
1240 * override the BDRV_O_PROTOCOL flag */
1241 protocol
= drv
->bdrv_file_open
;
1245 *flags
|= BDRV_O_PROTOCOL
;
1247 *flags
&= ~BDRV_O_PROTOCOL
;
1250 /* Translate cache options from flags into options */
1251 update_options_from_flags(*options
, *flags
);
1253 /* Fetch the file name from the options QDict if necessary */
1254 if (protocol
&& filename
) {
1255 if (!qdict_haskey(*options
, "filename")) {
1256 qdict_put(*options
, "filename", qstring_from_str(filename
));
1257 parse_filename
= true;
1259 error_setg(errp
, "Can't specify 'file' and 'filename' options at "
1265 /* Find the right block driver */
1266 filename
= qdict_get_try_str(*options
, "filename");
1268 if (!drvname
&& protocol
) {
1270 drv
= bdrv_find_protocol(filename
, parse_filename
, errp
);
1275 drvname
= drv
->format_name
;
1276 qdict_put(*options
, "driver", qstring_from_str(drvname
));
1278 error_setg(errp
, "Must specify either driver or file");
1283 assert(drv
|| !protocol
);
1285 /* Driver-specific filename parsing */
1286 if (drv
&& drv
->bdrv_parse_filename
&& parse_filename
) {
1287 drv
->bdrv_parse_filename(filename
, *options
, &local_err
);
1289 error_propagate(errp
, local_err
);
1293 if (!drv
->bdrv_needs_filename
) {
1294 qdict_del(*options
, "filename");
1301 static void bdrv_replace_child(BdrvChild
*child
, BlockDriverState
*new_bs
)
1303 BlockDriverState
*old_bs
= child
->bs
;
1306 if (old_bs
->quiesce_counter
&& child
->role
->drained_end
) {
1307 child
->role
->drained_end(child
);
1309 QLIST_REMOVE(child
, next_parent
);
1315 QLIST_INSERT_HEAD(&new_bs
->parents
, child
, next_parent
);
1316 if (new_bs
->quiesce_counter
&& child
->role
->drained_begin
) {
1317 child
->role
->drained_begin(child
);
1322 BdrvChild
*bdrv_root_attach_child(BlockDriverState
*child_bs
,
1323 const char *child_name
,
1324 const BdrvChildRole
*child_role
,
1327 BdrvChild
*child
= g_new(BdrvChild
, 1);
1328 *child
= (BdrvChild
) {
1330 .name
= g_strdup(child_name
),
1335 bdrv_replace_child(child
, child_bs
);
1340 BdrvChild
*bdrv_attach_child(BlockDriverState
*parent_bs
,
1341 BlockDriverState
*child_bs
,
1342 const char *child_name
,
1343 const BdrvChildRole
*child_role
)
1345 BdrvChild
*child
= bdrv_root_attach_child(child_bs
, child_name
, child_role
,
1347 QLIST_INSERT_HEAD(&parent_bs
->children
, child
, next
);
1351 static void bdrv_detach_child(BdrvChild
*child
)
1353 if (child
->next
.le_prev
) {
1354 QLIST_REMOVE(child
, next
);
1355 child
->next
.le_prev
= NULL
;
1358 bdrv_replace_child(child
, NULL
);
1360 g_free(child
->name
);
1364 void bdrv_root_unref_child(BdrvChild
*child
)
1366 BlockDriverState
*child_bs
;
1368 child_bs
= child
->bs
;
1369 bdrv_detach_child(child
);
1370 bdrv_unref(child_bs
);
1373 void bdrv_unref_child(BlockDriverState
*parent
, BdrvChild
*child
)
1375 if (child
== NULL
) {
1379 if (child
->bs
->inherits_from
== parent
) {
1382 /* Remove inherits_from only when the last reference between parent and
1383 * child->bs goes away. */
1384 QLIST_FOREACH(c
, &parent
->children
, next
) {
1385 if (c
!= child
&& c
->bs
== child
->bs
) {
1390 child
->bs
->inherits_from
= NULL
;
1394 bdrv_root_unref_child(child
);
1398 static void bdrv_parent_cb_change_media(BlockDriverState
*bs
, bool load
)
1401 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
1402 if (c
->role
->change_media
) {
1403 c
->role
->change_media(c
, load
);
1408 static void bdrv_parent_cb_resize(BlockDriverState
*bs
)
1411 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
1412 if (c
->role
->resize
) {
1419 * Sets the backing file link of a BDS. A new reference is created; callers
1420 * which don't need their own reference any more must call bdrv_unref().
1422 void bdrv_set_backing_hd(BlockDriverState
*bs
, BlockDriverState
*backing_hd
)
1425 bdrv_ref(backing_hd
);
1429 assert(bs
->backing_blocker
);
1430 bdrv_op_unblock_all(bs
->backing
->bs
, bs
->backing_blocker
);
1431 bdrv_unref_child(bs
, bs
->backing
);
1432 } else if (backing_hd
) {
1433 error_setg(&bs
->backing_blocker
,
1434 "node is used as backing hd of '%s'",
1435 bdrv_get_device_or_node_name(bs
));
1439 error_free(bs
->backing_blocker
);
1440 bs
->backing_blocker
= NULL
;
1444 bs
->backing
= bdrv_attach_child(bs
, backing_hd
, "backing", &child_backing
);
1445 bs
->open_flags
&= ~BDRV_O_NO_BACKING
;
1446 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
), backing_hd
->filename
);
1447 pstrcpy(bs
->backing_format
, sizeof(bs
->backing_format
),
1448 backing_hd
->drv
? backing_hd
->drv
->format_name
: "");
1450 bdrv_op_block_all(backing_hd
, bs
->backing_blocker
);
1451 /* Otherwise we won't be able to commit or stream */
1452 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_COMMIT_TARGET
,
1453 bs
->backing_blocker
);
1454 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_STREAM
,
1455 bs
->backing_blocker
);
1457 * We do backup in 3 ways:
1459 * The target bs is new opened, and the source is top BDS
1460 * 2. blockdev backup
1461 * Both the source and the target are top BDSes.
1462 * 3. internal backup(used for block replication)
1463 * Both the source and the target are backing file
1465 * In case 1 and 2, neither the source nor the target is the backing file.
1466 * In case 3, we will block the top BDS, so there is only one block job
1467 * for the top BDS and its backing chain.
1469 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_SOURCE
,
1470 bs
->backing_blocker
);
1471 bdrv_op_unblock(backing_hd
, BLOCK_OP_TYPE_BACKUP_TARGET
,
1472 bs
->backing_blocker
);
1474 bdrv_refresh_limits(bs
, NULL
);
1478 * Opens the backing file for a BlockDriverState if not yet open
1480 * bdref_key specifies the key for the image's BlockdevRef in the options QDict.
1481 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
1482 * itself, all options starting with "${bdref_key}." are considered part of the
1485 * TODO Can this be unified with bdrv_open_image()?
1487 int bdrv_open_backing_file(BlockDriverState
*bs
, QDict
*parent_options
,
1488 const char *bdref_key
, Error
**errp
)
1490 char *backing_filename
= g_malloc0(PATH_MAX
);
1491 char *bdref_key_dot
;
1492 const char *reference
= NULL
;
1494 BlockDriverState
*backing_hd
;
1496 QDict
*tmp_parent_options
= NULL
;
1497 Error
*local_err
= NULL
;
1499 if (bs
->backing
!= NULL
) {
1503 /* NULL means an empty set of options */
1504 if (parent_options
== NULL
) {
1505 tmp_parent_options
= qdict_new();
1506 parent_options
= tmp_parent_options
;
1509 bs
->open_flags
&= ~BDRV_O_NO_BACKING
;
1511 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
1512 qdict_extract_subqdict(parent_options
, &options
, bdref_key_dot
);
1513 g_free(bdref_key_dot
);
1515 reference
= qdict_get_try_str(parent_options
, bdref_key
);
1516 if (reference
|| qdict_haskey(options
, "file.filename")) {
1517 backing_filename
[0] = '\0';
1518 } else if (bs
->backing_file
[0] == '\0' && qdict_size(options
) == 0) {
1522 bdrv_get_full_backing_filename(bs
, backing_filename
, PATH_MAX
,
1526 error_propagate(errp
, local_err
);
1532 if (!bs
->drv
|| !bs
->drv
->supports_backing
) {
1534 error_setg(errp
, "Driver doesn't support backing files");
1539 if (bs
->backing_format
[0] != '\0' && !qdict_haskey(options
, "driver")) {
1540 qdict_put(options
, "driver", qstring_from_str(bs
->backing_format
));
1543 backing_hd
= bdrv_open_inherit(*backing_filename
? backing_filename
: NULL
,
1544 reference
, options
, 0, bs
, &child_backing
,
1547 bs
->open_flags
|= BDRV_O_NO_BACKING
;
1548 error_prepend(errp
, "Could not open backing file: ");
1553 /* Hook up the backing file link; drop our reference, bs owns the
1554 * backing_hd reference now */
1555 bdrv_set_backing_hd(bs
, backing_hd
);
1556 bdrv_unref(backing_hd
);
1558 qdict_del(parent_options
, bdref_key
);
1561 g_free(backing_filename
);
1562 QDECREF(tmp_parent_options
);
1566 static BlockDriverState
*
1567 bdrv_open_child_bs(const char *filename
, QDict
*options
, const char *bdref_key
,
1568 BlockDriverState
*parent
, const BdrvChildRole
*child_role
,
1569 bool allow_none
, Error
**errp
)
1571 BlockDriverState
*bs
= NULL
;
1572 QDict
*image_options
;
1573 char *bdref_key_dot
;
1574 const char *reference
;
1576 assert(child_role
!= NULL
);
1578 bdref_key_dot
= g_strdup_printf("%s.", bdref_key
);
1579 qdict_extract_subqdict(options
, &image_options
, bdref_key_dot
);
1580 g_free(bdref_key_dot
);
1582 reference
= qdict_get_try_str(options
, bdref_key
);
1583 if (!filename
&& !reference
&& !qdict_size(image_options
)) {
1585 error_setg(errp
, "A block device must be specified for \"%s\"",
1588 QDECREF(image_options
);
1592 bs
= bdrv_open_inherit(filename
, reference
, image_options
, 0,
1593 parent
, child_role
, errp
);
1599 qdict_del(options
, bdref_key
);
1604 * Opens a disk image whose options are given as BlockdevRef in another block
1607 * If allow_none is true, no image will be opened if filename is false and no
1608 * BlockdevRef is given. NULL will be returned, but errp remains unset.
1610 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
1611 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
1612 * itself, all options starting with "${bdref_key}." are considered part of the
1615 * The BlockdevRef will be removed from the options QDict.
1617 BdrvChild
*bdrv_open_child(const char *filename
,
1618 QDict
*options
, const char *bdref_key
,
1619 BlockDriverState
*parent
,
1620 const BdrvChildRole
*child_role
,
1621 bool allow_none
, Error
**errp
)
1623 BlockDriverState
*bs
;
1625 bs
= bdrv_open_child_bs(filename
, options
, bdref_key
, parent
, child_role
,
1631 return bdrv_attach_child(parent
, bs
, bdref_key
, child_role
);
1634 static BlockDriverState
*bdrv_append_temp_snapshot(BlockDriverState
*bs
,
1636 QDict
*snapshot_options
,
1639 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
1640 char *tmp_filename
= g_malloc0(PATH_MAX
+ 1);
1642 QemuOpts
*opts
= NULL
;
1643 BlockDriverState
*bs_snapshot
;
1646 /* if snapshot, we create a temporary backing file and open it
1647 instead of opening 'filename' directly */
1649 /* Get the required size from the image */
1650 total_size
= bdrv_getlength(bs
);
1651 if (total_size
< 0) {
1652 error_setg_errno(errp
, -total_size
, "Could not get image size");
1656 /* Create the temporary image */
1657 ret
= get_tmp_filename(tmp_filename
, PATH_MAX
+ 1);
1659 error_setg_errno(errp
, -ret
, "Could not get temporary filename");
1663 opts
= qemu_opts_create(bdrv_qcow2
.create_opts
, NULL
, 0,
1665 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, total_size
, &error_abort
);
1666 ret
= bdrv_create(&bdrv_qcow2
, tmp_filename
, opts
, errp
);
1667 qemu_opts_del(opts
);
1669 error_prepend(errp
, "Could not create temporary overlay '%s': ",
1674 /* Prepare options QDict for the temporary file */
1675 qdict_put(snapshot_options
, "file.driver",
1676 qstring_from_str("file"));
1677 qdict_put(snapshot_options
, "file.filename",
1678 qstring_from_str(tmp_filename
));
1679 qdict_put(snapshot_options
, "driver",
1680 qstring_from_str("qcow2"));
1682 bs_snapshot
= bdrv_open(NULL
, NULL
, snapshot_options
, flags
, errp
);
1683 snapshot_options
= NULL
;
1689 /* bdrv_append() consumes a strong reference to bs_snapshot (i.e. it will
1690 * call bdrv_unref() on it), so in order to be able to return one, we have
1691 * to increase bs_snapshot's refcount here */
1692 bdrv_ref(bs_snapshot
);
1693 bdrv_append(bs_snapshot
, bs
);
1695 g_free(tmp_filename
);
1699 QDECREF(snapshot_options
);
1700 g_free(tmp_filename
);
1705 * Opens a disk image (raw, qcow2, vmdk, ...)
1707 * options is a QDict of options to pass to the block drivers, or NULL for an
1708 * empty set of options. The reference to the QDict belongs to the block layer
1709 * after the call (even on failure), so if the caller intends to reuse the
1710 * dictionary, it needs to use QINCREF() before calling bdrv_open.
1712 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
1713 * If it is not NULL, the referenced BDS will be reused.
1715 * The reference parameter may be used to specify an existing block device which
1716 * should be opened. If specified, neither options nor a filename may be given,
1717 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
1719 static BlockDriverState
*bdrv_open_inherit(const char *filename
,
1720 const char *reference
,
1721 QDict
*options
, int flags
,
1722 BlockDriverState
*parent
,
1723 const BdrvChildRole
*child_role
,
1727 BlockBackend
*file
= NULL
;
1728 BlockDriverState
*bs
;
1729 BlockDriver
*drv
= NULL
;
1730 const char *drvname
;
1731 const char *backing
;
1732 Error
*local_err
= NULL
;
1733 QDict
*snapshot_options
= NULL
;
1734 int snapshot_flags
= 0;
1736 assert(!child_role
|| !flags
);
1737 assert(!child_role
== !parent
);
1740 bool options_non_empty
= options
? qdict_size(options
) : false;
1743 if (filename
|| options_non_empty
) {
1744 error_setg(errp
, "Cannot reference an existing block device with "
1745 "additional options or a new filename");
1749 bs
= bdrv_lookup_bs(reference
, reference
, errp
);
1760 /* NULL means an empty set of options */
1761 if (options
== NULL
) {
1762 options
= qdict_new();
1765 /* json: syntax counts as explicit options, as if in the QDict */
1766 parse_json_protocol(options
, &filename
, &local_err
);
1771 bs
->explicit_options
= qdict_clone_shallow(options
);
1774 bs
->inherits_from
= parent
;
1775 child_role
->inherit_options(&flags
, options
,
1776 parent
->open_flags
, parent
->options
);
1779 ret
= bdrv_fill_options(&options
, filename
, &flags
, &local_err
);
1784 /* Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags.
1785 * FIXME: we're parsing the QDict to avoid having to create a
1786 * QemuOpts just for this, but neither option is optimal. */
1787 if (g_strcmp0(qdict_get_try_str(options
, BDRV_OPT_READ_ONLY
), "on") &&
1788 !qdict_get_try_bool(options
, BDRV_OPT_READ_ONLY
, false)) {
1789 flags
|= (BDRV_O_RDWR
| BDRV_O_ALLOW_RDWR
);
1791 flags
&= ~BDRV_O_RDWR
;
1794 if (flags
& BDRV_O_SNAPSHOT
) {
1795 snapshot_options
= qdict_new();
1796 bdrv_temp_snapshot_options(&snapshot_flags
, snapshot_options
,
1798 /* Let bdrv_backing_options() override "read-only" */
1799 qdict_del(options
, BDRV_OPT_READ_ONLY
);
1800 bdrv_backing_options(&flags
, options
, flags
, options
);
1803 bs
->open_flags
= flags
;
1804 bs
->options
= options
;
1805 options
= qdict_clone_shallow(options
);
1807 /* Find the right image format driver */
1808 drvname
= qdict_get_try_str(options
, "driver");
1810 drv
= bdrv_find_format(drvname
);
1812 error_setg(errp
, "Unknown driver: '%s'", drvname
);
1817 assert(drvname
|| !(flags
& BDRV_O_PROTOCOL
));
1819 backing
= qdict_get_try_str(options
, "backing");
1820 if (backing
&& *backing
== '\0') {
1821 flags
|= BDRV_O_NO_BACKING
;
1822 qdict_del(options
, "backing");
1825 /* Open image file without format layer. This BlockBackend is only used for
1826 * probing, the block drivers will do their own bdrv_open_child() for the
1827 * same BDS, which is why we put the node name back into options. */
1828 if ((flags
& BDRV_O_PROTOCOL
) == 0) {
1829 BlockDriverState
*file_bs
;
1831 file_bs
= bdrv_open_child_bs(filename
, options
, "file", bs
,
1832 &child_file
, true, &local_err
);
1836 if (file_bs
!= NULL
) {
1838 blk_insert_bs(file
, file_bs
);
1839 bdrv_unref(file_bs
);
1841 qdict_put(options
, "file",
1842 qstring_from_str(bdrv_get_node_name(file_bs
)));
1846 /* Image format probing */
1849 ret
= find_image_format(file
, filename
, &drv
, &local_err
);
1854 * This option update would logically belong in bdrv_fill_options(),
1855 * but we first need to open bs->file for the probing to work, while
1856 * opening bs->file already requires the (mostly) final set of options
1857 * so that cache mode etc. can be inherited.
1859 * Adding the driver later is somewhat ugly, but it's not an option
1860 * that would ever be inherited, so it's correct. We just need to make
1861 * sure to update both bs->options (which has the full effective
1862 * options for bs) and options (which has file.* already removed).
1864 qdict_put(bs
->options
, "driver", qstring_from_str(drv
->format_name
));
1865 qdict_put(options
, "driver", qstring_from_str(drv
->format_name
));
1867 error_setg(errp
, "Must specify either driver or file");
1871 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */
1872 assert(!!(flags
& BDRV_O_PROTOCOL
) == !!drv
->bdrv_file_open
);
1873 /* file must be NULL if a protocol BDS is about to be created
1874 * (the inverse results in an error message from bdrv_open_common()) */
1875 assert(!(flags
& BDRV_O_PROTOCOL
) || !file
);
1877 /* Open the image */
1878 ret
= bdrv_open_common(bs
, file
, options
, &local_err
);
1888 /* If there is a backing file, use it */
1889 if ((flags
& BDRV_O_NO_BACKING
) == 0) {
1890 ret
= bdrv_open_backing_file(bs
, options
, "backing", &local_err
);
1892 goto close_and_fail
;
1896 bdrv_refresh_filename(bs
);
1898 /* Check if any unknown options were used */
1899 if (qdict_size(options
) != 0) {
1900 const QDictEntry
*entry
= qdict_first(options
);
1901 if (flags
& BDRV_O_PROTOCOL
) {
1902 error_setg(errp
, "Block protocol '%s' doesn't support the option "
1903 "'%s'", drv
->format_name
, entry
->key
);
1906 "Block format '%s' does not support the option '%s'",
1907 drv
->format_name
, entry
->key
);
1910 goto close_and_fail
;
1913 if (!bdrv_key_required(bs
)) {
1914 bdrv_parent_cb_change_media(bs
, true);
1915 } else if (!runstate_check(RUN_STATE_PRELAUNCH
)
1916 && !runstate_check(RUN_STATE_INMIGRATE
)
1917 && !runstate_check(RUN_STATE_PAUSED
)) { /* HACK */
1919 "Guest must be stopped for opening of encrypted image");
1920 goto close_and_fail
;
1925 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
1926 * temporary snapshot afterwards. */
1927 if (snapshot_flags
) {
1928 BlockDriverState
*snapshot_bs
;
1929 snapshot_bs
= bdrv_append_temp_snapshot(bs
, snapshot_flags
,
1930 snapshot_options
, &local_err
);
1931 snapshot_options
= NULL
;
1933 goto close_and_fail
;
1935 /* We are not going to return bs but the overlay on top of it
1936 * (snapshot_bs); thus, we have to drop the strong reference to bs
1937 * (which we obtained by calling bdrv_new()). bs will not be deleted,
1938 * though, because the overlay still has a reference to it. */
1947 if (bs
->file
!= NULL
) {
1948 bdrv_unref_child(bs
, bs
->file
);
1950 QDECREF(snapshot_options
);
1951 QDECREF(bs
->explicit_options
);
1952 QDECREF(bs
->options
);
1956 error_propagate(errp
, local_err
);
1961 QDECREF(snapshot_options
);
1963 error_propagate(errp
, local_err
);
1967 BlockDriverState
*bdrv_open(const char *filename
, const char *reference
,
1968 QDict
*options
, int flags
, Error
**errp
)
1970 return bdrv_open_inherit(filename
, reference
, options
, flags
, NULL
,
1974 typedef struct BlockReopenQueueEntry
{
1976 BDRVReopenState state
;
1977 QSIMPLEQ_ENTRY(BlockReopenQueueEntry
) entry
;
1978 } BlockReopenQueueEntry
;
1981 * Adds a BlockDriverState to a simple queue for an atomic, transactional
1982 * reopen of multiple devices.
1984 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT
1985 * already performed, or alternatively may be NULL a new BlockReopenQueue will
1986 * be created and initialized. This newly created BlockReopenQueue should be
1987 * passed back in for subsequent calls that are intended to be of the same
1990 * bs is the BlockDriverState to add to the reopen queue.
1992 * options contains the changed options for the associated bs
1993 * (the BlockReopenQueue takes ownership)
1995 * flags contains the open flags for the associated bs
1997 * returns a pointer to bs_queue, which is either the newly allocated
1998 * bs_queue, or the existing bs_queue being used.
2001 static BlockReopenQueue
*bdrv_reopen_queue_child(BlockReopenQueue
*bs_queue
,
2002 BlockDriverState
*bs
,
2005 const BdrvChildRole
*role
,
2006 QDict
*parent_options
,
2011 BlockReopenQueueEntry
*bs_entry
;
2013 QDict
*old_options
, *explicit_options
;
2015 if (bs_queue
== NULL
) {
2016 bs_queue
= g_new0(BlockReopenQueue
, 1);
2017 QSIMPLEQ_INIT(bs_queue
);
2021 options
= qdict_new();
2024 /* Check if this BlockDriverState is already in the queue */
2025 QSIMPLEQ_FOREACH(bs_entry
, bs_queue
, entry
) {
2026 if (bs
== bs_entry
->state
.bs
) {
2032 * Precedence of options:
2033 * 1. Explicitly passed in options (highest)
2034 * 2. Set in flags (only for top level)
2035 * 3. Retained from explicitly set options of bs
2036 * 4. Inherited from parent node
2037 * 5. Retained from effective options of bs
2040 if (!parent_options
) {
2042 * Any setting represented by flags is always updated. If the
2043 * corresponding QDict option is set, it takes precedence. Otherwise
2044 * the flag is translated into a QDict option. The old setting of bs is
2047 update_options_from_flags(options
, flags
);
2050 /* Old explicitly set values (don't overwrite by inherited value) */
2052 old_options
= qdict_clone_shallow(bs_entry
->state
.explicit_options
);
2054 old_options
= qdict_clone_shallow(bs
->explicit_options
);
2056 bdrv_join_options(bs
, options
, old_options
);
2057 QDECREF(old_options
);
2059 explicit_options
= qdict_clone_shallow(options
);
2061 /* Inherit from parent node */
2062 if (parent_options
) {
2064 role
->inherit_options(&flags
, options
, parent_flags
, parent_options
);
2067 /* Old values are used for options that aren't set yet */
2068 old_options
= qdict_clone_shallow(bs
->options
);
2069 bdrv_join_options(bs
, options
, old_options
);
2070 QDECREF(old_options
);
2072 /* bdrv_open() masks this flag out */
2073 flags
&= ~BDRV_O_PROTOCOL
;
2075 QLIST_FOREACH(child
, &bs
->children
, next
) {
2076 QDict
*new_child_options
;
2077 char *child_key_dot
;
2079 /* reopen can only change the options of block devices that were
2080 * implicitly created and inherited options. For other (referenced)
2081 * block devices, a syntax like "backing.foo" results in an error. */
2082 if (child
->bs
->inherits_from
!= bs
) {
2086 child_key_dot
= g_strdup_printf("%s.", child
->name
);
2087 qdict_extract_subqdict(options
, &new_child_options
, child_key_dot
);
2088 g_free(child_key_dot
);
2090 bdrv_reopen_queue_child(bs_queue
, child
->bs
, new_child_options
, 0,
2091 child
->role
, options
, flags
);
2095 bs_entry
= g_new0(BlockReopenQueueEntry
, 1);
2096 QSIMPLEQ_INSERT_TAIL(bs_queue
, bs_entry
, entry
);
2098 QDECREF(bs_entry
->state
.options
);
2099 QDECREF(bs_entry
->state
.explicit_options
);
2102 bs_entry
->state
.bs
= bs
;
2103 bs_entry
->state
.options
= options
;
2104 bs_entry
->state
.explicit_options
= explicit_options
;
2105 bs_entry
->state
.flags
= flags
;
2110 BlockReopenQueue
*bdrv_reopen_queue(BlockReopenQueue
*bs_queue
,
2111 BlockDriverState
*bs
,
2112 QDict
*options
, int flags
)
2114 return bdrv_reopen_queue_child(bs_queue
, bs
, options
, flags
,
2119 * Reopen multiple BlockDriverStates atomically & transactionally.
2121 * The queue passed in (bs_queue) must have been built up previous
2122 * via bdrv_reopen_queue().
2124 * Reopens all BDS specified in the queue, with the appropriate
2125 * flags. All devices are prepared for reopen, and failure of any
2126 * device will cause all device changes to be abandonded, and intermediate
2129 * If all devices prepare successfully, then the changes are committed
2133 int bdrv_reopen_multiple(AioContext
*ctx
, BlockReopenQueue
*bs_queue
, Error
**errp
)
2136 BlockReopenQueueEntry
*bs_entry
, *next
;
2137 Error
*local_err
= NULL
;
2139 assert(bs_queue
!= NULL
);
2141 aio_context_release(ctx
);
2142 bdrv_drain_all_begin();
2143 aio_context_acquire(ctx
);
2145 QSIMPLEQ_FOREACH(bs_entry
, bs_queue
, entry
) {
2146 if (bdrv_reopen_prepare(&bs_entry
->state
, bs_queue
, &local_err
)) {
2147 error_propagate(errp
, local_err
);
2150 bs_entry
->prepared
= true;
2153 /* If we reach this point, we have success and just need to apply the
2156 QSIMPLEQ_FOREACH(bs_entry
, bs_queue
, entry
) {
2157 bdrv_reopen_commit(&bs_entry
->state
);
2163 QSIMPLEQ_FOREACH_SAFE(bs_entry
, bs_queue
, entry
, next
) {
2164 if (ret
&& bs_entry
->prepared
) {
2165 bdrv_reopen_abort(&bs_entry
->state
);
2167 QDECREF(bs_entry
->state
.explicit_options
);
2169 QDECREF(bs_entry
->state
.options
);
2174 bdrv_drain_all_end();
2180 /* Reopen a single BlockDriverState with the specified flags. */
2181 int bdrv_reopen(BlockDriverState
*bs
, int bdrv_flags
, Error
**errp
)
2184 Error
*local_err
= NULL
;
2185 BlockReopenQueue
*queue
= bdrv_reopen_queue(NULL
, bs
, NULL
, bdrv_flags
);
2187 ret
= bdrv_reopen_multiple(bdrv_get_aio_context(bs
), queue
, &local_err
);
2188 if (local_err
!= NULL
) {
2189 error_propagate(errp
, local_err
);
2196 * Prepares a BlockDriverState for reopen. All changes are staged in the
2197 * 'opaque' field of the BDRVReopenState, which is used and allocated by
2198 * the block driver layer .bdrv_reopen_prepare()
2200 * bs is the BlockDriverState to reopen
2201 * flags are the new open flags
2202 * queue is the reopen queue
2204 * Returns 0 on success, non-zero on error. On error errp will be set
2207 * On failure, bdrv_reopen_abort() will be called to clean up any data.
2208 * It is the responsibility of the caller to then call the abort() or
2209 * commit() for any other BDS that have been left in a prepare() state
2212 int bdrv_reopen_prepare(BDRVReopenState
*reopen_state
, BlockReopenQueue
*queue
,
2216 Error
*local_err
= NULL
;
2221 assert(reopen_state
!= NULL
);
2222 assert(reopen_state
->bs
->drv
!= NULL
);
2223 drv
= reopen_state
->bs
->drv
;
2225 /* Process generic block layer options */
2226 opts
= qemu_opts_create(&bdrv_runtime_opts
, NULL
, 0, &error_abort
);
2227 qemu_opts_absorb_qdict(opts
, reopen_state
->options
, &local_err
);
2229 error_propagate(errp
, local_err
);
2234 update_flags_from_options(&reopen_state
->flags
, opts
);
2236 /* node-name and driver must be unchanged. Put them back into the QDict, so
2237 * that they are checked at the end of this function. */
2238 value
= qemu_opt_get(opts
, "node-name");
2240 qdict_put(reopen_state
->options
, "node-name", qstring_from_str(value
));
2243 value
= qemu_opt_get(opts
, "driver");
2245 qdict_put(reopen_state
->options
, "driver", qstring_from_str(value
));
2248 /* if we are to stay read-only, do not allow permission change
2250 if (!(reopen_state
->bs
->open_flags
& BDRV_O_ALLOW_RDWR
) &&
2251 reopen_state
->flags
& BDRV_O_RDWR
) {
2252 error_setg(errp
, "Node '%s' is read only",
2253 bdrv_get_device_or_node_name(reopen_state
->bs
));
2258 ret
= bdrv_flush(reopen_state
->bs
);
2260 error_setg_errno(errp
, -ret
, "Error flushing drive");
2264 if (drv
->bdrv_reopen_prepare
) {
2265 ret
= drv
->bdrv_reopen_prepare(reopen_state
, queue
, &local_err
);
2267 if (local_err
!= NULL
) {
2268 error_propagate(errp
, local_err
);
2270 error_setg(errp
, "failed while preparing to reopen image '%s'",
2271 reopen_state
->bs
->filename
);
2276 /* It is currently mandatory to have a bdrv_reopen_prepare()
2277 * handler for each supported drv. */
2278 error_setg(errp
, "Block format '%s' used by node '%s' "
2279 "does not support reopening files", drv
->format_name
,
2280 bdrv_get_device_or_node_name(reopen_state
->bs
));
2285 /* Options that are not handled are only okay if they are unchanged
2286 * compared to the old state. It is expected that some options are only
2287 * used for the initial open, but not reopen (e.g. filename) */
2288 if (qdict_size(reopen_state
->options
)) {
2289 const QDictEntry
*entry
= qdict_first(reopen_state
->options
);
2292 QString
*new_obj
= qobject_to_qstring(entry
->value
);
2293 const char *new = qstring_get_str(new_obj
);
2294 const char *old
= qdict_get_try_str(reopen_state
->bs
->options
,
2297 if (!old
|| strcmp(new, old
)) {
2298 error_setg(errp
, "Cannot change the option '%s'", entry
->key
);
2302 } while ((entry
= qdict_next(reopen_state
->options
, entry
)));
2308 qemu_opts_del(opts
);
2313 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
2314 * makes them final by swapping the staging BlockDriverState contents into
2315 * the active BlockDriverState contents.
2317 void bdrv_reopen_commit(BDRVReopenState
*reopen_state
)
2321 assert(reopen_state
!= NULL
);
2322 drv
= reopen_state
->bs
->drv
;
2323 assert(drv
!= NULL
);
2325 /* If there are any driver level actions to take */
2326 if (drv
->bdrv_reopen_commit
) {
2327 drv
->bdrv_reopen_commit(reopen_state
);
2330 /* set BDS specific flags now */
2331 QDECREF(reopen_state
->bs
->explicit_options
);
2333 reopen_state
->bs
->explicit_options
= reopen_state
->explicit_options
;
2334 reopen_state
->bs
->open_flags
= reopen_state
->flags
;
2335 reopen_state
->bs
->read_only
= !(reopen_state
->flags
& BDRV_O_RDWR
);
2337 bdrv_refresh_limits(reopen_state
->bs
, NULL
);
2341 * Abort the reopen, and delete and free the staged changes in
2344 void bdrv_reopen_abort(BDRVReopenState
*reopen_state
)
2348 assert(reopen_state
!= NULL
);
2349 drv
= reopen_state
->bs
->drv
;
2350 assert(drv
!= NULL
);
2352 if (drv
->bdrv_reopen_abort
) {
2353 drv
->bdrv_reopen_abort(reopen_state
);
2356 QDECREF(reopen_state
->explicit_options
);
2360 static void bdrv_close(BlockDriverState
*bs
)
2362 BdrvAioNotifier
*ban
, *ban_next
;
2365 assert(!bs
->refcnt
);
2367 bdrv_drained_begin(bs
); /* complete I/O */
2369 bdrv_drain(bs
); /* in case flush left pending I/O */
2371 bdrv_release_named_dirty_bitmaps(bs
);
2372 assert(QLIST_EMPTY(&bs
->dirty_bitmaps
));
2375 BdrvChild
*child
, *next
;
2377 bs
->drv
->bdrv_close(bs
);
2380 bdrv_set_backing_hd(bs
, NULL
);
2382 if (bs
->file
!= NULL
) {
2383 bdrv_unref_child(bs
, bs
->file
);
2387 QLIST_FOREACH_SAFE(child
, &bs
->children
, next
, next
) {
2388 /* TODO Remove bdrv_unref() from drivers' close function and use
2389 * bdrv_unref_child() here */
2390 if (child
->bs
->inherits_from
== bs
) {
2391 child
->bs
->inherits_from
= NULL
;
2393 bdrv_detach_child(child
);
2398 bs
->copy_on_read
= 0;
2399 bs
->backing_file
[0] = '\0';
2400 bs
->backing_format
[0] = '\0';
2401 bs
->total_sectors
= 0;
2402 bs
->encrypted
= false;
2403 bs
->valid_key
= false;
2405 QDECREF(bs
->options
);
2406 QDECREF(bs
->explicit_options
);
2408 QDECREF(bs
->full_open_options
);
2409 bs
->full_open_options
= NULL
;
2412 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_next
) {
2415 QLIST_INIT(&bs
->aio_notifiers
);
2416 bdrv_drained_end(bs
);
2419 void bdrv_close_all(void)
2421 block_job_cancel_sync_all();
2422 nbd_export_close_all();
2424 /* Drop references from requests still in flight, such as canceled block
2425 * jobs whose AIO context has not been polled yet */
2428 blk_remove_all_bs();
2429 blockdev_close_all_bdrv_states();
2431 assert(QTAILQ_EMPTY(&all_bdrv_states
));
2434 static void change_parent_backing_link(BlockDriverState
*from
,
2435 BlockDriverState
*to
)
2437 BdrvChild
*c
, *next
, *to_c
;
2439 QLIST_FOREACH_SAFE(c
, &from
->parents
, next_parent
, next
) {
2440 if (c
->role
== &child_backing
) {
2441 /* @from is generally not allowed to be a backing file, except for
2442 * when @to is the overlay. In that case, @from may not be replaced
2443 * by @to as @to's backing node. */
2444 QLIST_FOREACH(to_c
, &to
->children
, next
) {
2454 assert(c
->role
!= &child_backing
);
2456 bdrv_replace_child(c
, to
);
2462 * Add new bs contents at the top of an image chain while the chain is
2463 * live, while keeping required fields on the top layer.
2465 * This will modify the BlockDriverState fields, and swap contents
2466 * between bs_new and bs_top. Both bs_new and bs_top are modified.
2468 * bs_new must not be attached to a BlockBackend.
2470 * This function does not create any image files.
2472 * bdrv_append() takes ownership of a bs_new reference and unrefs it because
2473 * that's what the callers commonly need. bs_new will be referenced by the old
2474 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a
2475 * reference of its own, it must call bdrv_ref().
2477 void bdrv_append(BlockDriverState
*bs_new
, BlockDriverState
*bs_top
)
2479 assert(!bdrv_requests_pending(bs_top
));
2480 assert(!bdrv_requests_pending(bs_new
));
2484 change_parent_backing_link(bs_top
, bs_new
);
2485 bdrv_set_backing_hd(bs_new
, bs_top
);
2488 /* bs_new is now referenced by its new parents, we don't need the
2489 * additional reference any more. */
2493 void bdrv_replace_in_backing_chain(BlockDriverState
*old
, BlockDriverState
*new)
2495 assert(!bdrv_requests_pending(old
));
2496 assert(!bdrv_requests_pending(new));
2500 change_parent_backing_link(old
, new);
2505 static void bdrv_delete(BlockDriverState
*bs
)
2508 assert(bdrv_op_blocker_is_empty(bs
));
2509 assert(!bs
->refcnt
);
2513 /* remove from list, if necessary */
2514 if (bs
->node_name
[0] != '\0') {
2515 QTAILQ_REMOVE(&graph_bdrv_states
, bs
, node_list
);
2517 QTAILQ_REMOVE(&all_bdrv_states
, bs
, bs_list
);
2523 * Run consistency checks on an image
2525 * Returns 0 if the check could be completed (it doesn't mean that the image is
2526 * free of errors) or -errno when an internal error occurred. The results of the
2527 * check are stored in res.
2529 int bdrv_check(BlockDriverState
*bs
, BdrvCheckResult
*res
, BdrvCheckMode fix
)
2531 if (bs
->drv
== NULL
) {
2534 if (bs
->drv
->bdrv_check
== NULL
) {
2538 memset(res
, 0, sizeof(*res
));
2539 return bs
->drv
->bdrv_check(bs
, res
, fix
);
2545 * -EINVAL - backing format specified, but no file
2546 * -ENOSPC - can't update the backing file because no space is left in the
2548 * -ENOTSUP - format driver doesn't support changing the backing file
2550 int bdrv_change_backing_file(BlockDriverState
*bs
,
2551 const char *backing_file
, const char *backing_fmt
)
2553 BlockDriver
*drv
= bs
->drv
;
2556 /* Backing file format doesn't make sense without a backing file */
2557 if (backing_fmt
&& !backing_file
) {
2561 if (drv
->bdrv_change_backing_file
!= NULL
) {
2562 ret
= drv
->bdrv_change_backing_file(bs
, backing_file
, backing_fmt
);
2568 pstrcpy(bs
->backing_file
, sizeof(bs
->backing_file
), backing_file
?: "");
2569 pstrcpy(bs
->backing_format
, sizeof(bs
->backing_format
), backing_fmt
?: "");
2575 * Finds the image layer in the chain that has 'bs' as its backing file.
2577 * active is the current topmost image.
2579 * Returns NULL if bs is not found in active's image chain,
2580 * or if active == bs.
2582 * Returns the bottommost base image if bs == NULL.
2584 BlockDriverState
*bdrv_find_overlay(BlockDriverState
*active
,
2585 BlockDriverState
*bs
)
2587 while (active
&& bs
!= backing_bs(active
)) {
2588 active
= backing_bs(active
);
2594 /* Given a BDS, searches for the base layer. */
2595 BlockDriverState
*bdrv_find_base(BlockDriverState
*bs
)
2597 return bdrv_find_overlay(bs
, NULL
);
2601 * Drops images above 'base' up to and including 'top', and sets the image
2602 * above 'top' to have base as its backing file.
2604 * Requires that the overlay to 'top' is opened r/w, so that the backing file
2605 * information in 'bs' can be properly updated.
2607 * E.g., this will convert the following chain:
2608 * bottom <- base <- intermediate <- top <- active
2612 * bottom <- base <- active
2614 * It is allowed for bottom==base, in which case it converts:
2616 * base <- intermediate <- top <- active
2622 * If backing_file_str is non-NULL, it will be used when modifying top's
2623 * overlay image metadata.
2626 * if active == top, that is considered an error
2629 int bdrv_drop_intermediate(BlockDriverState
*active
, BlockDriverState
*top
,
2630 BlockDriverState
*base
, const char *backing_file_str
)
2632 BlockDriverState
*new_top_bs
= NULL
;
2635 if (!top
->drv
|| !base
->drv
) {
2639 new_top_bs
= bdrv_find_overlay(active
, top
);
2641 if (new_top_bs
== NULL
) {
2642 /* we could not find the image above 'top', this is an error */
2646 /* special case of new_top_bs->backing->bs already pointing to base - nothing
2647 * to do, no intermediate images */
2648 if (backing_bs(new_top_bs
) == base
) {
2653 /* Make sure that base is in the backing chain of top */
2654 if (!bdrv_chain_contains(top
, base
)) {
2658 /* success - we can delete the intermediate states, and link top->base */
2659 backing_file_str
= backing_file_str
? backing_file_str
: base
->filename
;
2660 ret
= bdrv_change_backing_file(new_top_bs
, backing_file_str
,
2661 base
->drv
? base
->drv
->format_name
: "");
2665 bdrv_set_backing_hd(new_top_bs
, base
);
2673 * Truncate file to 'offset' bytes (needed only for file protocols)
2675 int bdrv_truncate(BdrvChild
*child
, int64_t offset
)
2677 BlockDriverState
*bs
= child
->bs
;
2678 BlockDriver
*drv
= bs
->drv
;
2682 if (!drv
->bdrv_truncate
)
2687 ret
= drv
->bdrv_truncate(bs
, offset
);
2689 ret
= refresh_total_sectors(bs
, offset
>> BDRV_SECTOR_BITS
);
2690 bdrv_dirty_bitmap_truncate(bs
);
2691 bdrv_parent_cb_resize(bs
);
2698 * Length of a allocated file in bytes. Sparse files are counted by actual
2699 * allocated space. Return < 0 if error or unknown.
2701 int64_t bdrv_get_allocated_file_size(BlockDriverState
*bs
)
2703 BlockDriver
*drv
= bs
->drv
;
2707 if (drv
->bdrv_get_allocated_file_size
) {
2708 return drv
->bdrv_get_allocated_file_size(bs
);
2711 return bdrv_get_allocated_file_size(bs
->file
->bs
);
2717 * Return number of sectors on success, -errno on error.
2719 int64_t bdrv_nb_sectors(BlockDriverState
*bs
)
2721 BlockDriver
*drv
= bs
->drv
;
2726 if (drv
->has_variable_length
) {
2727 int ret
= refresh_total_sectors(bs
, bs
->total_sectors
);
2732 return bs
->total_sectors
;
2736 * Return length in bytes on success, -errno on error.
2737 * The length is always a multiple of BDRV_SECTOR_SIZE.
2739 int64_t bdrv_getlength(BlockDriverState
*bs
)
2741 int64_t ret
= bdrv_nb_sectors(bs
);
2743 ret
= ret
> INT64_MAX
/ BDRV_SECTOR_SIZE
? -EFBIG
: ret
;
2744 return ret
< 0 ? ret
: ret
* BDRV_SECTOR_SIZE
;
2747 /* return 0 as number of sectors if no device present or error */
2748 void bdrv_get_geometry(BlockDriverState
*bs
, uint64_t *nb_sectors_ptr
)
2750 int64_t nb_sectors
= bdrv_nb_sectors(bs
);
2752 *nb_sectors_ptr
= nb_sectors
< 0 ? 0 : nb_sectors
;
2755 bool bdrv_is_read_only(BlockDriverState
*bs
)
2757 return bs
->read_only
;
2760 bool bdrv_is_sg(BlockDriverState
*bs
)
2765 bool bdrv_is_encrypted(BlockDriverState
*bs
)
2767 if (bs
->backing
&& bs
->backing
->bs
->encrypted
) {
2770 return bs
->encrypted
;
2773 bool bdrv_key_required(BlockDriverState
*bs
)
2775 BdrvChild
*backing
= bs
->backing
;
2777 if (backing
&& backing
->bs
->encrypted
&& !backing
->bs
->valid_key
) {
2780 return (bs
->encrypted
&& !bs
->valid_key
);
2783 int bdrv_set_key(BlockDriverState
*bs
, const char *key
)
2786 if (bs
->backing
&& bs
->backing
->bs
->encrypted
) {
2787 ret
= bdrv_set_key(bs
->backing
->bs
, key
);
2793 if (!bs
->encrypted
) {
2795 } else if (!bs
->drv
|| !bs
->drv
->bdrv_set_key
) {
2798 ret
= bs
->drv
->bdrv_set_key(bs
, key
);
2800 bs
->valid_key
= false;
2801 } else if (!bs
->valid_key
) {
2802 /* call the change callback now, we skipped it on open */
2803 bs
->valid_key
= true;
2804 bdrv_parent_cb_change_media(bs
, true);
2810 * Provide an encryption key for @bs.
2811 * If @key is non-null:
2812 * If @bs is not encrypted, fail.
2813 * Else if the key is invalid, fail.
2814 * Else set @bs's key to @key, replacing the existing key, if any.
2816 * If @bs is encrypted and still lacks a key, fail.
2818 * On failure, store an error object through @errp if non-null.
2820 void bdrv_add_key(BlockDriverState
*bs
, const char *key
, Error
**errp
)
2823 if (!bdrv_is_encrypted(bs
)) {
2824 error_setg(errp
, "Node '%s' is not encrypted",
2825 bdrv_get_device_or_node_name(bs
));
2826 } else if (bdrv_set_key(bs
, key
) < 0) {
2827 error_setg(errp
, QERR_INVALID_PASSWORD
);
2830 if (bdrv_key_required(bs
)) {
2831 error_set(errp
, ERROR_CLASS_DEVICE_ENCRYPTED
,
2832 "'%s' (%s) is encrypted",
2833 bdrv_get_device_or_node_name(bs
),
2834 bdrv_get_encrypted_filename(bs
));
2839 const char *bdrv_get_format_name(BlockDriverState
*bs
)
2841 return bs
->drv
? bs
->drv
->format_name
: NULL
;
2844 static int qsort_strcmp(const void *a
, const void *b
)
2846 return strcmp(*(char *const *)a
, *(char *const *)b
);
2849 void bdrv_iterate_format(void (*it
)(void *opaque
, const char *name
),
2855 const char **formats
= NULL
;
2857 QLIST_FOREACH(drv
, &bdrv_drivers
, list
) {
2858 if (drv
->format_name
) {
2861 while (formats
&& i
&& !found
) {
2862 found
= !strcmp(formats
[--i
], drv
->format_name
);
2866 formats
= g_renew(const char *, formats
, count
+ 1);
2867 formats
[count
++] = drv
->format_name
;
2872 for (i
= 0; i
< (int)ARRAY_SIZE(block_driver_modules
); i
++) {
2873 const char *format_name
= block_driver_modules
[i
].format_name
;
2879 while (formats
&& j
&& !found
) {
2880 found
= !strcmp(formats
[--j
], format_name
);
2884 formats
= g_renew(const char *, formats
, count
+ 1);
2885 formats
[count
++] = format_name
;
2890 qsort(formats
, count
, sizeof(formats
[0]), qsort_strcmp
);
2892 for (i
= 0; i
< count
; i
++) {
2893 it(opaque
, formats
[i
]);
2899 /* This function is to find a node in the bs graph */
2900 BlockDriverState
*bdrv_find_node(const char *node_name
)
2902 BlockDriverState
*bs
;
2906 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
2907 if (!strcmp(node_name
, bs
->node_name
)) {
2914 /* Put this QMP function here so it can access the static graph_bdrv_states. */
2915 BlockDeviceInfoList
*bdrv_named_nodes_list(Error
**errp
)
2917 BlockDeviceInfoList
*list
, *entry
;
2918 BlockDriverState
*bs
;
2921 QTAILQ_FOREACH(bs
, &graph_bdrv_states
, node_list
) {
2922 BlockDeviceInfo
*info
= bdrv_block_device_info(NULL
, bs
, errp
);
2924 qapi_free_BlockDeviceInfoList(list
);
2927 entry
= g_malloc0(sizeof(*entry
));
2928 entry
->value
= info
;
2936 BlockDriverState
*bdrv_lookup_bs(const char *device
,
2937 const char *node_name
,
2941 BlockDriverState
*bs
;
2944 blk
= blk_by_name(device
);
2949 error_setg(errp
, "Device '%s' has no medium", device
);
2957 bs
= bdrv_find_node(node_name
);
2964 error_setg(errp
, "Cannot find device=%s nor node_name=%s",
2965 device
? device
: "",
2966 node_name
? node_name
: "");
2970 /* If 'base' is in the same chain as 'top', return true. Otherwise,
2971 * return false. If either argument is NULL, return false. */
2972 bool bdrv_chain_contains(BlockDriverState
*top
, BlockDriverState
*base
)
2974 while (top
&& top
!= base
) {
2975 top
= backing_bs(top
);
2981 BlockDriverState
*bdrv_next_node(BlockDriverState
*bs
)
2984 return QTAILQ_FIRST(&graph_bdrv_states
);
2986 return QTAILQ_NEXT(bs
, node_list
);
2989 const char *bdrv_get_node_name(const BlockDriverState
*bs
)
2991 return bs
->node_name
;
2994 const char *bdrv_get_parent_name(const BlockDriverState
*bs
)
2999 /* If multiple parents have a name, just pick the first one. */
3000 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
3001 if (c
->role
->get_name
) {
3002 name
= c
->role
->get_name(c
);
3003 if (name
&& *name
) {
3012 /* TODO check what callers really want: bs->node_name or blk_name() */
3013 const char *bdrv_get_device_name(const BlockDriverState
*bs
)
3015 return bdrv_get_parent_name(bs
) ?: "";
3018 /* This can be used to identify nodes that might not have a device
3019 * name associated. Since node and device names live in the same
3020 * namespace, the result is unambiguous. The exception is if both are
3021 * absent, then this returns an empty (non-null) string. */
3022 const char *bdrv_get_device_or_node_name(const BlockDriverState
*bs
)
3024 return bdrv_get_parent_name(bs
) ?: bs
->node_name
;
3027 int bdrv_get_flags(BlockDriverState
*bs
)
3029 return bs
->open_flags
;
3032 int bdrv_has_zero_init_1(BlockDriverState
*bs
)
3037 int bdrv_has_zero_init(BlockDriverState
*bs
)
3041 /* If BS is a copy on write image, it is initialized to
3042 the contents of the base image, which may not be zeroes. */
3046 if (bs
->drv
->bdrv_has_zero_init
) {
3047 return bs
->drv
->bdrv_has_zero_init(bs
);
3054 bool bdrv_unallocated_blocks_are_zero(BlockDriverState
*bs
)
3056 BlockDriverInfo bdi
;
3062 if (bdrv_get_info(bs
, &bdi
) == 0) {
3063 return bdi
.unallocated_blocks_are_zero
;
3069 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState
*bs
)
3071 BlockDriverInfo bdi
;
3073 if (!(bs
->open_flags
& BDRV_O_UNMAP
)) {
3077 if (bdrv_get_info(bs
, &bdi
) == 0) {
3078 return bdi
.can_write_zeroes_with_unmap
;
3084 const char *bdrv_get_encrypted_filename(BlockDriverState
*bs
)
3086 if (bs
->backing
&& bs
->backing
->bs
->encrypted
)
3087 return bs
->backing_file
;
3088 else if (bs
->encrypted
)
3089 return bs
->filename
;
3094 void bdrv_get_backing_filename(BlockDriverState
*bs
,
3095 char *filename
, int filename_size
)
3097 pstrcpy(filename
, filename_size
, bs
->backing_file
);
3100 int bdrv_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
3102 BlockDriver
*drv
= bs
->drv
;
3105 if (!drv
->bdrv_get_info
)
3107 memset(bdi
, 0, sizeof(*bdi
));
3108 return drv
->bdrv_get_info(bs
, bdi
);
3111 ImageInfoSpecific
*bdrv_get_specific_info(BlockDriverState
*bs
)
3113 BlockDriver
*drv
= bs
->drv
;
3114 if (drv
&& drv
->bdrv_get_specific_info
) {
3115 return drv
->bdrv_get_specific_info(bs
);
3120 void bdrv_debug_event(BlockDriverState
*bs
, BlkdebugEvent event
)
3122 if (!bs
|| !bs
->drv
|| !bs
->drv
->bdrv_debug_event
) {
3126 bs
->drv
->bdrv_debug_event(bs
, event
);
3129 int bdrv_debug_breakpoint(BlockDriverState
*bs
, const char *event
,
3132 while (bs
&& bs
->drv
&& !bs
->drv
->bdrv_debug_breakpoint
) {
3133 bs
= bs
->file
? bs
->file
->bs
: NULL
;
3136 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_breakpoint
) {
3137 return bs
->drv
->bdrv_debug_breakpoint(bs
, event
, tag
);
3143 int bdrv_debug_remove_breakpoint(BlockDriverState
*bs
, const char *tag
)
3145 while (bs
&& bs
->drv
&& !bs
->drv
->bdrv_debug_remove_breakpoint
) {
3146 bs
= bs
->file
? bs
->file
->bs
: NULL
;
3149 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_remove_breakpoint
) {
3150 return bs
->drv
->bdrv_debug_remove_breakpoint(bs
, tag
);
3156 int bdrv_debug_resume(BlockDriverState
*bs
, const char *tag
)
3158 while (bs
&& (!bs
->drv
|| !bs
->drv
->bdrv_debug_resume
)) {
3159 bs
= bs
->file
? bs
->file
->bs
: NULL
;
3162 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_resume
) {
3163 return bs
->drv
->bdrv_debug_resume(bs
, tag
);
3169 bool bdrv_debug_is_suspended(BlockDriverState
*bs
, const char *tag
)
3171 while (bs
&& bs
->drv
&& !bs
->drv
->bdrv_debug_is_suspended
) {
3172 bs
= bs
->file
? bs
->file
->bs
: NULL
;
3175 if (bs
&& bs
->drv
&& bs
->drv
->bdrv_debug_is_suspended
) {
3176 return bs
->drv
->bdrv_debug_is_suspended(bs
, tag
);
3182 /* backing_file can either be relative, or absolute, or a protocol. If it is
3183 * relative, it must be relative to the chain. So, passing in bs->filename
3184 * from a BDS as backing_file should not be done, as that may be relative to
3185 * the CWD rather than the chain. */
3186 BlockDriverState
*bdrv_find_backing_image(BlockDriverState
*bs
,
3187 const char *backing_file
)
3189 char *filename_full
= NULL
;
3190 char *backing_file_full
= NULL
;
3191 char *filename_tmp
= NULL
;
3192 int is_protocol
= 0;
3193 BlockDriverState
*curr_bs
= NULL
;
3194 BlockDriverState
*retval
= NULL
;
3195 Error
*local_error
= NULL
;
3197 if (!bs
|| !bs
->drv
|| !backing_file
) {
3201 filename_full
= g_malloc(PATH_MAX
);
3202 backing_file_full
= g_malloc(PATH_MAX
);
3203 filename_tmp
= g_malloc(PATH_MAX
);
3205 is_protocol
= path_has_protocol(backing_file
);
3207 for (curr_bs
= bs
; curr_bs
->backing
; curr_bs
= curr_bs
->backing
->bs
) {
3209 /* If either of the filename paths is actually a protocol, then
3210 * compare unmodified paths; otherwise make paths relative */
3211 if (is_protocol
|| path_has_protocol(curr_bs
->backing_file
)) {
3212 if (strcmp(backing_file
, curr_bs
->backing_file
) == 0) {
3213 retval
= curr_bs
->backing
->bs
;
3216 /* Also check against the full backing filename for the image */
3217 bdrv_get_full_backing_filename(curr_bs
, backing_file_full
, PATH_MAX
,
3219 if (local_error
== NULL
) {
3220 if (strcmp(backing_file
, backing_file_full
) == 0) {
3221 retval
= curr_bs
->backing
->bs
;
3225 error_free(local_error
);
3229 /* If not an absolute filename path, make it relative to the current
3230 * image's filename path */
3231 path_combine(filename_tmp
, PATH_MAX
, curr_bs
->filename
,
3234 /* We are going to compare absolute pathnames */
3235 if (!realpath(filename_tmp
, filename_full
)) {
3239 /* We need to make sure the backing filename we are comparing against
3240 * is relative to the current image filename (or absolute) */
3241 path_combine(filename_tmp
, PATH_MAX
, curr_bs
->filename
,
3242 curr_bs
->backing_file
);
3244 if (!realpath(filename_tmp
, backing_file_full
)) {
3248 if (strcmp(backing_file_full
, filename_full
) == 0) {
3249 retval
= curr_bs
->backing
->bs
;
3255 g_free(filename_full
);
3256 g_free(backing_file_full
);
3257 g_free(filename_tmp
);
3261 int bdrv_get_backing_file_depth(BlockDriverState
*bs
)
3271 return 1 + bdrv_get_backing_file_depth(bs
->backing
->bs
);
3274 void bdrv_init(void)
3276 module_call_init(MODULE_INIT_BLOCK
);
3279 void bdrv_init_with_whitelist(void)
3281 use_bdrv_whitelist
= 1;
3285 void bdrv_invalidate_cache(BlockDriverState
*bs
, Error
**errp
)
3288 Error
*local_err
= NULL
;
3295 if (!(bs
->open_flags
& BDRV_O_INACTIVE
)) {
3299 QLIST_FOREACH(child
, &bs
->children
, next
) {
3300 bdrv_invalidate_cache(child
->bs
, &local_err
);
3302 error_propagate(errp
, local_err
);
3307 bs
->open_flags
&= ~BDRV_O_INACTIVE
;
3308 if (bs
->drv
->bdrv_invalidate_cache
) {
3309 bs
->drv
->bdrv_invalidate_cache(bs
, &local_err
);
3311 bs
->open_flags
|= BDRV_O_INACTIVE
;
3312 error_propagate(errp
, local_err
);
3317 ret
= refresh_total_sectors(bs
, bs
->total_sectors
);
3319 bs
->open_flags
|= BDRV_O_INACTIVE
;
3320 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
3325 void bdrv_invalidate_cache_all(Error
**errp
)
3327 BlockDriverState
*bs
;
3328 Error
*local_err
= NULL
;
3329 BdrvNextIterator it
;
3331 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
3332 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
3334 aio_context_acquire(aio_context
);
3335 bdrv_invalidate_cache(bs
, &local_err
);
3336 aio_context_release(aio_context
);
3338 error_propagate(errp
, local_err
);
3344 static int bdrv_inactivate_recurse(BlockDriverState
*bs
,
3350 if (!setting_flag
&& bs
->drv
->bdrv_inactivate
) {
3351 ret
= bs
->drv
->bdrv_inactivate(bs
);
3357 QLIST_FOREACH(child
, &bs
->children
, next
) {
3358 ret
= bdrv_inactivate_recurse(child
->bs
, setting_flag
);
3365 bs
->open_flags
|= BDRV_O_INACTIVE
;
3370 int bdrv_inactivate_all(void)
3372 BlockDriverState
*bs
= NULL
;
3373 BdrvNextIterator it
;
3377 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
3378 aio_context_acquire(bdrv_get_aio_context(bs
));
3381 /* We do two passes of inactivation. The first pass calls to drivers'
3382 * .bdrv_inactivate callbacks recursively so all cache is flushed to disk;
3383 * the second pass sets the BDRV_O_INACTIVE flag so that no further write
3385 for (pass
= 0; pass
< 2; pass
++) {
3386 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
3387 ret
= bdrv_inactivate_recurse(bs
, pass
);
3395 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
3396 aio_context_release(bdrv_get_aio_context(bs
));
3402 /**************************************************************/
3403 /* removable device support */
3406 * Return TRUE if the media is present
3408 bool bdrv_is_inserted(BlockDriverState
*bs
)
3410 BlockDriver
*drv
= bs
->drv
;
3416 if (drv
->bdrv_is_inserted
) {
3417 return drv
->bdrv_is_inserted(bs
);
3419 QLIST_FOREACH(child
, &bs
->children
, next
) {
3420 if (!bdrv_is_inserted(child
->bs
)) {
3428 * Return whether the media changed since the last call to this
3429 * function, or -ENOTSUP if we don't know. Most drivers don't know.
3431 int bdrv_media_changed(BlockDriverState
*bs
)
3433 BlockDriver
*drv
= bs
->drv
;
3435 if (drv
&& drv
->bdrv_media_changed
) {
3436 return drv
->bdrv_media_changed(bs
);
3442 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
3444 void bdrv_eject(BlockDriverState
*bs
, bool eject_flag
)
3446 BlockDriver
*drv
= bs
->drv
;
3448 if (drv
&& drv
->bdrv_eject
) {
3449 drv
->bdrv_eject(bs
, eject_flag
);
3454 * Lock or unlock the media (if it is locked, the user won't be able
3455 * to eject it manually).
3457 void bdrv_lock_medium(BlockDriverState
*bs
, bool locked
)
3459 BlockDriver
*drv
= bs
->drv
;
3461 trace_bdrv_lock_medium(bs
, locked
);
3463 if (drv
&& drv
->bdrv_lock_medium
) {
3464 drv
->bdrv_lock_medium(bs
, locked
);
3468 /* Get a reference to bs */
3469 void bdrv_ref(BlockDriverState
*bs
)
3474 /* Release a previously grabbed reference to bs.
3475 * If after releasing, reference count is zero, the BlockDriverState is
3477 void bdrv_unref(BlockDriverState
*bs
)
3482 assert(bs
->refcnt
> 0);
3483 if (--bs
->refcnt
== 0) {
3488 struct BdrvOpBlocker
{
3490 QLIST_ENTRY(BdrvOpBlocker
) list
;
3493 bool bdrv_op_is_blocked(BlockDriverState
*bs
, BlockOpType op
, Error
**errp
)
3495 BdrvOpBlocker
*blocker
;
3496 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
3497 if (!QLIST_EMPTY(&bs
->op_blockers
[op
])) {
3498 blocker
= QLIST_FIRST(&bs
->op_blockers
[op
]);
3500 *errp
= error_copy(blocker
->reason
);
3501 error_prepend(errp
, "Node '%s' is busy: ",
3502 bdrv_get_device_or_node_name(bs
));
3509 void bdrv_op_block(BlockDriverState
*bs
, BlockOpType op
, Error
*reason
)
3511 BdrvOpBlocker
*blocker
;
3512 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
3514 blocker
= g_new0(BdrvOpBlocker
, 1);
3515 blocker
->reason
= reason
;
3516 QLIST_INSERT_HEAD(&bs
->op_blockers
[op
], blocker
, list
);
3519 void bdrv_op_unblock(BlockDriverState
*bs
, BlockOpType op
, Error
*reason
)
3521 BdrvOpBlocker
*blocker
, *next
;
3522 assert((int) op
>= 0 && op
< BLOCK_OP_TYPE_MAX
);
3523 QLIST_FOREACH_SAFE(blocker
, &bs
->op_blockers
[op
], list
, next
) {
3524 if (blocker
->reason
== reason
) {
3525 QLIST_REMOVE(blocker
, list
);
3531 void bdrv_op_block_all(BlockDriverState
*bs
, Error
*reason
)
3534 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
3535 bdrv_op_block(bs
, i
, reason
);
3539 void bdrv_op_unblock_all(BlockDriverState
*bs
, Error
*reason
)
3542 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
3543 bdrv_op_unblock(bs
, i
, reason
);
3547 bool bdrv_op_blocker_is_empty(BlockDriverState
*bs
)
3551 for (i
= 0; i
< BLOCK_OP_TYPE_MAX
; i
++) {
3552 if (!QLIST_EMPTY(&bs
->op_blockers
[i
])) {
3559 void bdrv_img_create(const char *filename
, const char *fmt
,
3560 const char *base_filename
, const char *base_fmt
,
3561 char *options
, uint64_t img_size
, int flags
,
3562 Error
**errp
, bool quiet
)
3564 QemuOptsList
*create_opts
= NULL
;
3565 QemuOpts
*opts
= NULL
;
3566 const char *backing_fmt
, *backing_file
;
3568 BlockDriver
*drv
, *proto_drv
;
3569 Error
*local_err
= NULL
;
3572 /* Find driver and parse its options */
3573 drv
= bdrv_find_format(fmt
);
3575 error_setg(errp
, "Unknown file format '%s'", fmt
);
3579 proto_drv
= bdrv_find_protocol(filename
, true, errp
);
3584 if (!drv
->create_opts
) {
3585 error_setg(errp
, "Format driver '%s' does not support image creation",
3590 if (!proto_drv
->create_opts
) {
3591 error_setg(errp
, "Protocol driver '%s' does not support image creation",
3592 proto_drv
->format_name
);
3596 create_opts
= qemu_opts_append(create_opts
, drv
->create_opts
);
3597 create_opts
= qemu_opts_append(create_opts
, proto_drv
->create_opts
);
3599 /* Create parameter list with default values */
3600 opts
= qemu_opts_create(create_opts
, NULL
, 0, &error_abort
);
3601 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, img_size
, &error_abort
);
3603 /* Parse -o options */
3605 qemu_opts_do_parse(opts
, options
, NULL
, &local_err
);
3607 error_report_err(local_err
);
3609 error_setg(errp
, "Invalid options for file format '%s'", fmt
);
3614 if (base_filename
) {
3615 qemu_opt_set(opts
, BLOCK_OPT_BACKING_FILE
, base_filename
, &local_err
);
3617 error_setg(errp
, "Backing file not supported for file format '%s'",
3624 qemu_opt_set(opts
, BLOCK_OPT_BACKING_FMT
, base_fmt
, &local_err
);
3626 error_setg(errp
, "Backing file format not supported for file "
3627 "format '%s'", fmt
);
3632 backing_file
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FILE
);
3634 if (!strcmp(filename
, backing_file
)) {
3635 error_setg(errp
, "Error: Trying to create an image with the "
3636 "same filename as the backing file");
3641 backing_fmt
= qemu_opt_get(opts
, BLOCK_OPT_BACKING_FMT
);
3643 // The size for the image must always be specified, with one exception:
3644 // If we are using a backing file, we can obtain the size from there
3645 size
= qemu_opt_get_size(opts
, BLOCK_OPT_SIZE
, 0);
3648 BlockDriverState
*bs
;
3649 char *full_backing
= g_new0(char, PATH_MAX
);
3652 QDict
*backing_options
= NULL
;
3654 bdrv_get_full_backing_filename_from_filename(filename
, backing_file
,
3655 full_backing
, PATH_MAX
,
3658 g_free(full_backing
);
3662 /* backing files always opened read-only */
3664 back_flags
&= ~(BDRV_O_RDWR
| BDRV_O_SNAPSHOT
| BDRV_O_NO_BACKING
);
3667 backing_options
= qdict_new();
3668 qdict_put(backing_options
, "driver",
3669 qstring_from_str(backing_fmt
));
3672 bs
= bdrv_open(full_backing
, NULL
, backing_options
, back_flags
,
3674 g_free(full_backing
);
3678 size
= bdrv_getlength(bs
);
3680 error_setg_errno(errp
, -size
, "Could not get size of '%s'",
3686 qemu_opt_set_number(opts
, BLOCK_OPT_SIZE
, size
, &error_abort
);
3690 error_setg(errp
, "Image creation needs a size parameter");
3696 printf("Formatting '%s', fmt=%s ", filename
, fmt
);
3697 qemu_opts_print(opts
, " ");
3701 ret
= bdrv_create(drv
, filename
, opts
, &local_err
);
3703 if (ret
== -EFBIG
) {
3704 /* This is generally a better message than whatever the driver would
3705 * deliver (especially because of the cluster_size_hint), since that
3706 * is most probably not much different from "image too large". */
3707 const char *cluster_size_hint
= "";
3708 if (qemu_opt_get_size(opts
, BLOCK_OPT_CLUSTER_SIZE
, 0)) {
3709 cluster_size_hint
= " (try using a larger cluster size)";
3711 error_setg(errp
, "The image size is too large for file format '%s'"
3712 "%s", fmt
, cluster_size_hint
);
3713 error_free(local_err
);
3718 qemu_opts_del(opts
);
3719 qemu_opts_free(create_opts
);
3720 error_propagate(errp
, local_err
);
3723 AioContext
*bdrv_get_aio_context(BlockDriverState
*bs
)
3725 return bs
->aio_context
;
3728 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier
*ban
)
3730 QLIST_REMOVE(ban
, list
);
3734 void bdrv_detach_aio_context(BlockDriverState
*bs
)
3736 BdrvAioNotifier
*baf
, *baf_tmp
;
3743 assert(!bs
->walking_aio_notifiers
);
3744 bs
->walking_aio_notifiers
= true;
3745 QLIST_FOREACH_SAFE(baf
, &bs
->aio_notifiers
, list
, baf_tmp
) {
3747 bdrv_do_remove_aio_context_notifier(baf
);
3749 baf
->detach_aio_context(baf
->opaque
);
3752 /* Never mind iterating again to check for ->deleted. bdrv_close() will
3753 * remove remaining aio notifiers if we aren't called again.
3755 bs
->walking_aio_notifiers
= false;
3757 if (bs
->drv
->bdrv_detach_aio_context
) {
3758 bs
->drv
->bdrv_detach_aio_context(bs
);
3760 QLIST_FOREACH(child
, &bs
->children
, next
) {
3761 bdrv_detach_aio_context(child
->bs
);
3764 bs
->aio_context
= NULL
;
3767 void bdrv_attach_aio_context(BlockDriverState
*bs
,
3768 AioContext
*new_context
)
3770 BdrvAioNotifier
*ban
, *ban_tmp
;
3777 bs
->aio_context
= new_context
;
3779 QLIST_FOREACH(child
, &bs
->children
, next
) {
3780 bdrv_attach_aio_context(child
->bs
, new_context
);
3782 if (bs
->drv
->bdrv_attach_aio_context
) {
3783 bs
->drv
->bdrv_attach_aio_context(bs
, new_context
);
3786 assert(!bs
->walking_aio_notifiers
);
3787 bs
->walking_aio_notifiers
= true;
3788 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_tmp
) {
3790 bdrv_do_remove_aio_context_notifier(ban
);
3792 ban
->attached_aio_context(new_context
, ban
->opaque
);
3795 bs
->walking_aio_notifiers
= false;
3798 void bdrv_set_aio_context(BlockDriverState
*bs
, AioContext
*new_context
)
3800 bdrv_drain(bs
); /* ensure there are no in-flight requests */
3802 bdrv_detach_aio_context(bs
);
3804 /* This function executes in the old AioContext so acquire the new one in
3805 * case it runs in a different thread.
3807 aio_context_acquire(new_context
);
3808 bdrv_attach_aio_context(bs
, new_context
);
3809 aio_context_release(new_context
);
3812 void bdrv_add_aio_context_notifier(BlockDriverState
*bs
,
3813 void (*attached_aio_context
)(AioContext
*new_context
, void *opaque
),
3814 void (*detach_aio_context
)(void *opaque
), void *opaque
)
3816 BdrvAioNotifier
*ban
= g_new(BdrvAioNotifier
, 1);
3817 *ban
= (BdrvAioNotifier
){
3818 .attached_aio_context
= attached_aio_context
,
3819 .detach_aio_context
= detach_aio_context
,
3823 QLIST_INSERT_HEAD(&bs
->aio_notifiers
, ban
, list
);
3826 void bdrv_remove_aio_context_notifier(BlockDriverState
*bs
,
3827 void (*attached_aio_context
)(AioContext
*,
3829 void (*detach_aio_context
)(void *),
3832 BdrvAioNotifier
*ban
, *ban_next
;
3834 QLIST_FOREACH_SAFE(ban
, &bs
->aio_notifiers
, list
, ban_next
) {
3835 if (ban
->attached_aio_context
== attached_aio_context
&&
3836 ban
->detach_aio_context
== detach_aio_context
&&
3837 ban
->opaque
== opaque
&&
3838 ban
->deleted
== false)
3840 if (bs
->walking_aio_notifiers
) {
3841 ban
->deleted
= true;
3843 bdrv_do_remove_aio_context_notifier(ban
);
3852 int bdrv_amend_options(BlockDriverState
*bs
, QemuOpts
*opts
,
3853 BlockDriverAmendStatusCB
*status_cb
, void *cb_opaque
)
3855 if (!bs
->drv
->bdrv_amend_options
) {
3858 return bs
->drv
->bdrv_amend_options(bs
, opts
, status_cb
, cb_opaque
);
3861 /* This function will be called by the bdrv_recurse_is_first_non_filter method
3862 * of block filter and by bdrv_is_first_non_filter.
3863 * It is used to test if the given bs is the candidate or recurse more in the
3866 bool bdrv_recurse_is_first_non_filter(BlockDriverState
*bs
,
3867 BlockDriverState
*candidate
)
3869 /* return false if basic checks fails */
3870 if (!bs
|| !bs
->drv
) {
3874 /* the code reached a non block filter driver -> check if the bs is
3875 * the same as the candidate. It's the recursion termination condition.
3877 if (!bs
->drv
->is_filter
) {
3878 return bs
== candidate
;
3880 /* Down this path the driver is a block filter driver */
3882 /* If the block filter recursion method is defined use it to recurse down
3885 if (bs
->drv
->bdrv_recurse_is_first_non_filter
) {
3886 return bs
->drv
->bdrv_recurse_is_first_non_filter(bs
, candidate
);
3889 /* the driver is a block filter but don't allow to recurse -> return false
3894 /* This function checks if the candidate is the first non filter bs down it's
3895 * bs chain. Since we don't have pointers to parents it explore all bs chains
3896 * from the top. Some filters can choose not to pass down the recursion.
3898 bool bdrv_is_first_non_filter(BlockDriverState
*candidate
)
3900 BlockDriverState
*bs
;
3901 BdrvNextIterator it
;
3903 /* walk down the bs forest recursively */
3904 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
3907 /* try to recurse in this top level bs */
3908 perm
= bdrv_recurse_is_first_non_filter(bs
, candidate
);
3910 /* candidate is the first non filter */
3919 BlockDriverState
*check_to_replace_node(BlockDriverState
*parent_bs
,
3920 const char *node_name
, Error
**errp
)
3922 BlockDriverState
*to_replace_bs
= bdrv_find_node(node_name
);
3923 AioContext
*aio_context
;
3925 if (!to_replace_bs
) {
3926 error_setg(errp
, "Node name '%s' not found", node_name
);
3930 aio_context
= bdrv_get_aio_context(to_replace_bs
);
3931 aio_context_acquire(aio_context
);
3933 if (bdrv_op_is_blocked(to_replace_bs
, BLOCK_OP_TYPE_REPLACE
, errp
)) {
3934 to_replace_bs
= NULL
;
3938 /* We don't want arbitrary node of the BDS chain to be replaced only the top
3939 * most non filter in order to prevent data corruption.
3940 * Another benefit is that this tests exclude backing files which are
3941 * blocked by the backing blockers.
3943 if (!bdrv_recurse_is_first_non_filter(parent_bs
, to_replace_bs
)) {
3944 error_setg(errp
, "Only top most non filter can be replaced");
3945 to_replace_bs
= NULL
;
3950 aio_context_release(aio_context
);
3951 return to_replace_bs
;
3954 static bool append_open_options(QDict
*d
, BlockDriverState
*bs
)
3956 const QDictEntry
*entry
;
3959 bool found_any
= false;
3962 for (entry
= qdict_first(bs
->options
); entry
;
3963 entry
= qdict_next(bs
->options
, entry
))
3965 /* Exclude options for children */
3966 QLIST_FOREACH(child
, &bs
->children
, next
) {
3967 if (strstart(qdict_entry_key(entry
), child
->name
, &p
)
3968 && (!*p
|| *p
== '.'))
3977 /* And exclude all non-driver-specific options */
3978 for (desc
= bdrv_runtime_opts
.desc
; desc
->name
; desc
++) {
3979 if (!strcmp(qdict_entry_key(entry
), desc
->name
)) {
3987 qobject_incref(qdict_entry_value(entry
));
3988 qdict_put_obj(d
, qdict_entry_key(entry
), qdict_entry_value(entry
));
3995 /* Updates the following BDS fields:
3996 * - exact_filename: A filename which may be used for opening a block device
3997 * which (mostly) equals the given BDS (even without any
3998 * other options; so reading and writing must return the same
3999 * results, but caching etc. may be different)
4000 * - full_open_options: Options which, when given when opening a block device
4001 * (without a filename), result in a BDS (mostly)
4002 * equalling the given one
4003 * - filename: If exact_filename is set, it is copied here. Otherwise,
4004 * full_open_options is converted to a JSON object, prefixed with
4005 * "json:" (for use through the JSON pseudo protocol) and put here.
4007 void bdrv_refresh_filename(BlockDriverState
*bs
)
4009 BlockDriver
*drv
= bs
->drv
;
4016 /* This BDS's file name will most probably depend on its file's name, so
4017 * refresh that first */
4019 bdrv_refresh_filename(bs
->file
->bs
);
4022 if (drv
->bdrv_refresh_filename
) {
4023 /* Obsolete information is of no use here, so drop the old file name
4024 * information before refreshing it */
4025 bs
->exact_filename
[0] = '\0';
4026 if (bs
->full_open_options
) {
4027 QDECREF(bs
->full_open_options
);
4028 bs
->full_open_options
= NULL
;
4032 append_open_options(opts
, bs
);
4033 drv
->bdrv_refresh_filename(bs
, opts
);
4035 } else if (bs
->file
) {
4036 /* Try to reconstruct valid information from the underlying file */
4037 bool has_open_options
;
4039 bs
->exact_filename
[0] = '\0';
4040 if (bs
->full_open_options
) {
4041 QDECREF(bs
->full_open_options
);
4042 bs
->full_open_options
= NULL
;
4046 has_open_options
= append_open_options(opts
, bs
);
4048 /* If no specific options have been given for this BDS, the filename of
4049 * the underlying file should suffice for this one as well */
4050 if (bs
->file
->bs
->exact_filename
[0] && !has_open_options
) {
4051 strcpy(bs
->exact_filename
, bs
->file
->bs
->exact_filename
);
4053 /* Reconstructing the full options QDict is simple for most format block
4054 * drivers, as long as the full options are known for the underlying
4055 * file BDS. The full options QDict of that file BDS should somehow
4056 * contain a representation of the filename, therefore the following
4057 * suffices without querying the (exact_)filename of this BDS. */
4058 if (bs
->file
->bs
->full_open_options
) {
4059 qdict_put_obj(opts
, "driver",
4060 QOBJECT(qstring_from_str(drv
->format_name
)));
4061 QINCREF(bs
->file
->bs
->full_open_options
);
4062 qdict_put_obj(opts
, "file",
4063 QOBJECT(bs
->file
->bs
->full_open_options
));
4065 bs
->full_open_options
= opts
;
4069 } else if (!bs
->full_open_options
&& qdict_size(bs
->options
)) {
4070 /* There is no underlying file BDS (at least referenced by BDS.file),
4071 * so the full options QDict should be equal to the options given
4072 * specifically for this block device when it was opened (plus the
4073 * driver specification).
4074 * Because those options don't change, there is no need to update
4075 * full_open_options when it's already set. */
4078 append_open_options(opts
, bs
);
4079 qdict_put_obj(opts
, "driver",
4080 QOBJECT(qstring_from_str(drv
->format_name
)));
4082 if (bs
->exact_filename
[0]) {
4083 /* This may not work for all block protocol drivers (some may
4084 * require this filename to be parsed), but we have to find some
4085 * default solution here, so just include it. If some block driver
4086 * does not support pure options without any filename at all or
4087 * needs some special format of the options QDict, it needs to
4088 * implement the driver-specific bdrv_refresh_filename() function.
4090 qdict_put_obj(opts
, "filename",
4091 QOBJECT(qstring_from_str(bs
->exact_filename
)));
4094 bs
->full_open_options
= opts
;
4097 if (bs
->exact_filename
[0]) {
4098 pstrcpy(bs
->filename
, sizeof(bs
->filename
), bs
->exact_filename
);
4099 } else if (bs
->full_open_options
) {
4100 QString
*json
= qobject_to_json(QOBJECT(bs
->full_open_options
));
4101 snprintf(bs
->filename
, sizeof(bs
->filename
), "json:%s",
4102 qstring_get_str(json
));
4108 * Hot add/remove a BDS's child. So the user can take a child offline when
4109 * it is broken and take a new child online
4111 void bdrv_add_child(BlockDriverState
*parent_bs
, BlockDriverState
*child_bs
,
4115 if (!parent_bs
->drv
|| !parent_bs
->drv
->bdrv_add_child
) {
4116 error_setg(errp
, "The node %s does not support adding a child",
4117 bdrv_get_device_or_node_name(parent_bs
));
4121 if (!QLIST_EMPTY(&child_bs
->parents
)) {
4122 error_setg(errp
, "The node %s already has a parent",
4123 child_bs
->node_name
);
4127 parent_bs
->drv
->bdrv_add_child(parent_bs
, child_bs
, errp
);
4130 void bdrv_del_child(BlockDriverState
*parent_bs
, BdrvChild
*child
, Error
**errp
)
4134 if (!parent_bs
->drv
|| !parent_bs
->drv
->bdrv_del_child
) {
4135 error_setg(errp
, "The node %s does not support removing a child",
4136 bdrv_get_device_or_node_name(parent_bs
));
4140 QLIST_FOREACH(tmp
, &parent_bs
->children
, next
) {
4147 error_setg(errp
, "The node %s does not have a child named %s",
4148 bdrv_get_device_or_node_name(parent_bs
),
4149 bdrv_get_device_or_node_name(child
->bs
));
4153 parent_bs
->drv
->bdrv_del_child(parent_bs
, child
, errp
);