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
27 #include "block/accounting.h"
28 #include "block/block.h"
29 #include "block/aio-wait.h"
30 #include "qemu/queue.h"
31 #include "qemu/coroutine.h"
32 #include "qemu/stats64.h"
33 #include "qemu/timer.h"
34 #include "qemu/hbitmap.h"
35 #include "block/snapshot.h"
36 #include "qemu/throttle.h"
39 #define BLOCK_FLAG_LAZY_REFCOUNTS 8
41 #define BLOCK_OPT_SIZE "size"
42 #define BLOCK_OPT_ENCRYPT "encryption"
43 #define BLOCK_OPT_ENCRYPT_FORMAT "encrypt.format"
44 #define BLOCK_OPT_COMPAT6 "compat6"
45 #define BLOCK_OPT_HWVERSION "hwversion"
46 #define BLOCK_OPT_BACKING_FILE "backing_file"
47 #define BLOCK_OPT_BACKING_FMT "backing_fmt"
48 #define BLOCK_OPT_CLUSTER_SIZE "cluster_size"
49 #define BLOCK_OPT_TABLE_SIZE "table_size"
50 #define BLOCK_OPT_PREALLOC "preallocation"
51 #define BLOCK_OPT_SUBFMT "subformat"
52 #define BLOCK_OPT_COMPAT_LEVEL "compat"
53 #define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts"
54 #define BLOCK_OPT_ADAPTER_TYPE "adapter_type"
55 #define BLOCK_OPT_REDUNDANCY "redundancy"
56 #define BLOCK_OPT_NOCOW "nocow"
57 #define BLOCK_OPT_EXTENT_SIZE_HINT "extent_size_hint"
58 #define BLOCK_OPT_OBJECT_SIZE "object_size"
59 #define BLOCK_OPT_REFCOUNT_BITS "refcount_bits"
60 #define BLOCK_OPT_DATA_FILE "data_file"
61 #define BLOCK_OPT_DATA_FILE_RAW "data_file_raw"
62 #define BLOCK_OPT_COMPRESSION_TYPE "compression_type"
63 #define BLOCK_OPT_EXTL2 "extended_l2"
65 #define BLOCK_PROBE_BUF_SIZE 512
67 enum BdrvTrackedRequestType
{
71 BDRV_TRACKED_TRUNCATE
,
75 * That is not quite good that BdrvTrackedRequest structure is public,
76 * as block/io.c is very careful about incoming offset/bytes being
77 * correct. Be sure to assert bdrv_check_request() succeeded after any
78 * modification of BdrvTrackedRequest object out of block/io.c
80 typedef struct BdrvTrackedRequest
{
84 enum BdrvTrackedRequestType type
;
87 int64_t overlap_offset
;
88 int64_t overlap_bytes
;
90 QLIST_ENTRY(BdrvTrackedRequest
) list
;
91 Coroutine
*co
; /* owner, used for deadlock detection */
92 CoQueue wait_queue
; /* coroutines blocked on this request */
94 struct BdrvTrackedRequest
*waiting_for
;
97 int bdrv_check_request(int64_t offset
, int64_t bytes
, Error
**errp
);
100 const char *format_name
;
103 /* set to true if the BlockDriver is a block filter. Block filters pass
104 * certain callbacks that refer to data (see block.c) to their bs->file
105 * or bs->backing (whichever one exists) if the driver doesn't implement
106 * them. Drivers that do not wish to forward must implement them and return
108 * Note that filters are not allowed to modify data.
110 * Filters generally cannot have more than a single filtered child,
111 * because the data they present must at all times be the same as
112 * that on their filtered child. That would be impossible to
113 * achieve for multiple filtered children.
114 * (And this filtered child must then be bs->file or bs->backing.)
118 * Set to true if the BlockDriver is a format driver. Format nodes
119 * generally do not expect their children to be other format nodes
120 * (except for backing files), and so format probing is disabled
125 * Return true if @to_replace can be replaced by a BDS with the
126 * same data as @bs without it affecting @bs's behavior (that is,
127 * without it being visible to @bs's parents).
129 bool (*bdrv_recurse_can_replace
)(BlockDriverState
*bs
,
130 BlockDriverState
*to_replace
);
132 int (*bdrv_probe
)(const uint8_t *buf
, int buf_size
, const char *filename
);
133 int (*bdrv_probe_device
)(const char *filename
);
135 /* Any driver implementing this callback is expected to be able to handle
136 * NULL file names in its .bdrv_open() implementation */
137 void (*bdrv_parse_filename
)(const char *filename
, QDict
*options
, Error
**errp
);
138 /* Drivers not implementing bdrv_parse_filename nor bdrv_open should have
139 * this field set to true, except ones that are defined only by their
141 * An example of the last type will be the quorum block driver.
143 bool bdrv_needs_filename
;
146 * Set if a driver can support backing files. This also implies the
147 * following semantics:
149 * - Return status 0 of .bdrv_co_block_status means that corresponding
150 * blocks are not allocated in this layer of backing-chain
151 * - For such (unallocated) blocks, read will:
152 * - fill buffer with zeros if there is no backing file
153 * - read from the backing file otherwise, where the block layer
154 * takes care of reading zeros beyond EOF if backing file is short
156 bool supports_backing
;
158 /* For handling image reopen for split or non-split files */
159 int (*bdrv_reopen_prepare
)(BDRVReopenState
*reopen_state
,
160 BlockReopenQueue
*queue
, Error
**errp
);
161 void (*bdrv_reopen_commit
)(BDRVReopenState
*reopen_state
);
162 void (*bdrv_reopen_commit_post
)(BDRVReopenState
*reopen_state
);
163 void (*bdrv_reopen_abort
)(BDRVReopenState
*reopen_state
);
164 void (*bdrv_join_options
)(QDict
*options
, QDict
*old_options
);
166 int (*bdrv_open
)(BlockDriverState
*bs
, QDict
*options
, int flags
,
169 /* Protocol drivers should implement this instead of bdrv_open */
170 int (*bdrv_file_open
)(BlockDriverState
*bs
, QDict
*options
, int flags
,
172 void (*bdrv_close
)(BlockDriverState
*bs
);
175 int coroutine_fn (*bdrv_co_create
)(BlockdevCreateOptions
*opts
,
177 int coroutine_fn (*bdrv_co_create_opts
)(BlockDriver
*drv
,
178 const char *filename
,
182 int coroutine_fn (*bdrv_co_amend
)(BlockDriverState
*bs
,
183 BlockdevAmendOptions
*opts
,
187 int (*bdrv_amend_options
)(BlockDriverState
*bs
,
189 BlockDriverAmendStatusCB
*status_cb
,
194 int (*bdrv_make_empty
)(BlockDriverState
*bs
);
197 * Refreshes the bs->exact_filename field. If that is impossible,
198 * bs->exact_filename has to be left empty.
200 void (*bdrv_refresh_filename
)(BlockDriverState
*bs
);
203 * Gathers the open options for all children into @target.
204 * A simple format driver (without backing file support) might
205 * implement this function like this:
207 * QINCREF(bs->file->bs->full_open_options);
208 * qdict_put(target, "file", bs->file->bs->full_open_options);
210 * If not specified, the generic implementation will simply put
211 * all children's options under their respective name.
213 * @backing_overridden is true when bs->backing seems not to be
214 * the child that would result from opening bs->backing_file.
215 * Therefore, if it is true, the backing child's options should be
216 * gathered; otherwise, there is no need since the backing child
217 * is the one implied by the image header.
219 * Note that ideally this function would not be needed. Every
220 * block driver which implements it is probably doing something
221 * shady regarding its runtime option structure.
223 void (*bdrv_gather_child_options
)(BlockDriverState
*bs
, QDict
*target
,
224 bool backing_overridden
);
227 * Returns an allocated string which is the directory name of this BDS: It
228 * will be used to make relative filenames absolute by prepending this
229 * function's return value to them.
231 char *(*bdrv_dirname
)(BlockDriverState
*bs
, Error
**errp
);
234 BlockAIOCB
*(*bdrv_aio_preadv
)(BlockDriverState
*bs
,
235 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
, int flags
,
236 BlockCompletionFunc
*cb
, void *opaque
);
237 BlockAIOCB
*(*bdrv_aio_pwritev
)(BlockDriverState
*bs
,
238 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
, int flags
,
239 BlockCompletionFunc
*cb
, void *opaque
);
240 BlockAIOCB
*(*bdrv_aio_flush
)(BlockDriverState
*bs
,
241 BlockCompletionFunc
*cb
, void *opaque
);
242 BlockAIOCB
*(*bdrv_aio_pdiscard
)(BlockDriverState
*bs
,
243 int64_t offset
, int bytes
,
244 BlockCompletionFunc
*cb
, void *opaque
);
246 int coroutine_fn (*bdrv_co_readv
)(BlockDriverState
*bs
,
247 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
);
250 * @offset: position in bytes to read at
251 * @bytes: number of bytes to read
252 * @qiov: the buffers to fill with read data
253 * @flags: currently unused, always 0
255 * @offset and @bytes will be a multiple of 'request_alignment',
256 * but the length of individual @qiov elements does not have to
259 * @bytes will always equal the total size of @qiov, and will be
260 * no larger than 'max_transfer'.
262 * The buffer in @qiov may point directly to guest memory.
264 int coroutine_fn (*bdrv_co_preadv
)(BlockDriverState
*bs
,
265 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
, int flags
);
266 int coroutine_fn (*bdrv_co_preadv_part
)(BlockDriverState
*bs
,
267 uint64_t offset
, uint64_t bytes
,
268 QEMUIOVector
*qiov
, size_t qiov_offset
, int flags
);
269 int coroutine_fn (*bdrv_co_writev
)(BlockDriverState
*bs
,
270 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
, int flags
);
272 * @offset: position in bytes to write at
273 * @bytes: number of bytes to write
274 * @qiov: the buffers containing data to write
275 * @flags: zero or more bits allowed by 'supported_write_flags'
277 * @offset and @bytes will be a multiple of 'request_alignment',
278 * but the length of individual @qiov elements does not have to
281 * @bytes will always equal the total size of @qiov, and will be
282 * no larger than 'max_transfer'.
284 * The buffer in @qiov may point directly to guest memory.
286 int coroutine_fn (*bdrv_co_pwritev
)(BlockDriverState
*bs
,
287 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
, int flags
);
288 int coroutine_fn (*bdrv_co_pwritev_part
)(BlockDriverState
*bs
,
289 uint64_t offset
, uint64_t bytes
,
290 QEMUIOVector
*qiov
, size_t qiov_offset
, int flags
);
293 * Efficiently zero a region of the disk image. Typically an image format
294 * would use a compact metadata representation to implement this. This
295 * function pointer may be NULL or return -ENOSUP and .bdrv_co_writev()
296 * will be called instead.
298 int coroutine_fn (*bdrv_co_pwrite_zeroes
)(BlockDriverState
*bs
,
299 int64_t offset
, int bytes
, BdrvRequestFlags flags
);
300 int coroutine_fn (*bdrv_co_pdiscard
)(BlockDriverState
*bs
,
301 int64_t offset
, int bytes
);
303 /* Map [offset, offset + nbytes) range onto a child of @bs to copy from,
304 * and invoke bdrv_co_copy_range_from(child, ...), or invoke
305 * bdrv_co_copy_range_to() if @bs is the leaf child to copy data from.
307 * See the comment of bdrv_co_copy_range for the parameter and return value
310 int coroutine_fn (*bdrv_co_copy_range_from
)(BlockDriverState
*bs
,
316 BdrvRequestFlags read_flags
,
317 BdrvRequestFlags write_flags
);
319 /* Map [offset, offset + nbytes) range onto a child of bs to copy data to,
320 * and invoke bdrv_co_copy_range_to(child, src, ...), or perform the copy
321 * operation if @bs is the leaf and @src has the same BlockDriver. Return
322 * -ENOTSUP if @bs is the leaf but @src has a different BlockDriver.
324 * See the comment of bdrv_co_copy_range for the parameter and return value
327 int coroutine_fn (*bdrv_co_copy_range_to
)(BlockDriverState
*bs
,
333 BdrvRequestFlags read_flags
,
334 BdrvRequestFlags write_flags
);
337 * Building block for bdrv_block_status[_above] and
338 * bdrv_is_allocated[_above]. The driver should answer only
339 * according to the current layer, and should only need to set
340 * BDRV_BLOCK_DATA, BDRV_BLOCK_ZERO, BDRV_BLOCK_OFFSET_VALID,
341 * and/or BDRV_BLOCK_RAW; if the current layer defers to a backing
342 * layer, the result should be 0 (and not BDRV_BLOCK_ZERO). See
343 * block.h for the overall meaning of the bits. As a hint, the
344 * flag want_zero is true if the caller cares more about precise
345 * mappings (favor accurate _OFFSET_VALID/_ZERO) or false for
346 * overall allocation (favor larger *pnum, perhaps by reporting
347 * _DATA instead of _ZERO). The block layer guarantees input
348 * clamped to bdrv_getlength() and aligned to request_alignment,
349 * as well as non-NULL pnum, map, and file; in turn, the driver
350 * must return an error or set pnum to an aligned non-zero value.
352 * Note that @bytes is just a hint on how big of a region the
353 * caller wants to inspect. It is not a limit on *pnum.
354 * Implementations are free to return larger values of *pnum if
355 * doing so does not incur a performance penalty.
357 * block/io.c's bdrv_co_block_status() will utilize an unclamped
358 * *pnum value for the block-status cache on protocol nodes, prior
359 * to clamping *pnum for return to its caller.
361 int coroutine_fn (*bdrv_co_block_status
)(BlockDriverState
*bs
,
362 bool want_zero
, int64_t offset
, int64_t bytes
, int64_t *pnum
,
363 int64_t *map
, BlockDriverState
**file
);
366 * This informs the driver that we are no longer interested in the result
367 * of in-flight requests, so don't waste the time if possible.
369 * One example usage is to avoid waiting for an nbd target node reconnect
370 * timeout during job-cancel with force=true.
372 void (*bdrv_cancel_in_flight
)(BlockDriverState
*bs
);
375 * Invalidate any cached meta-data.
377 void coroutine_fn (*bdrv_co_invalidate_cache
)(BlockDriverState
*bs
,
379 int (*bdrv_inactivate
)(BlockDriverState
*bs
);
382 * Flushes all data for all layers by calling bdrv_co_flush for underlying
383 * layers, if needed. This function is needed for deterministic
384 * synchronization of the flush finishing callback.
386 int coroutine_fn (*bdrv_co_flush
)(BlockDriverState
*bs
);
388 /* Delete a created file. */
389 int coroutine_fn (*bdrv_co_delete_file
)(BlockDriverState
*bs
,
393 * Flushes all data that was already written to the OS all the way down to
394 * the disk (for example file-posix.c calls fsync()).
396 int coroutine_fn (*bdrv_co_flush_to_disk
)(BlockDriverState
*bs
);
399 * Flushes all internal caches to the OS. The data may still sit in a
400 * writeback cache of the host OS, but it will survive a crash of the qemu
403 int coroutine_fn (*bdrv_co_flush_to_os
)(BlockDriverState
*bs
);
406 * Drivers setting this field must be able to work with just a plain
407 * filename with '<protocol_name>:' as a prefix, and no other options.
408 * Options may be extracted from the filename by implementing
409 * bdrv_parse_filename.
411 const char *protocol_name
;
414 * Truncate @bs to @offset bytes using the given @prealloc mode
415 * when growing. Modes other than PREALLOC_MODE_OFF should be
416 * rejected when shrinking @bs.
418 * If @exact is true, @bs must be resized to exactly @offset.
419 * Otherwise, it is sufficient for @bs (if it is a host block
420 * device and thus there is no way to resize it) to be at least
421 * @offset bytes in length.
423 * If @exact is true and this function fails but would succeed
424 * with @exact = false, it should return -ENOTSUP.
426 int coroutine_fn (*bdrv_co_truncate
)(BlockDriverState
*bs
, int64_t offset
,
427 bool exact
, PreallocMode prealloc
,
428 BdrvRequestFlags flags
, Error
**errp
);
430 int64_t (*bdrv_getlength
)(BlockDriverState
*bs
);
431 bool has_variable_length
;
432 int64_t (*bdrv_get_allocated_file_size
)(BlockDriverState
*bs
);
433 BlockMeasureInfo
*(*bdrv_measure
)(QemuOpts
*opts
, BlockDriverState
*in_bs
,
436 int coroutine_fn (*bdrv_co_pwritev_compressed
)(BlockDriverState
*bs
,
437 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
);
438 int coroutine_fn (*bdrv_co_pwritev_compressed_part
)(BlockDriverState
*bs
,
439 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
,
442 int (*bdrv_snapshot_create
)(BlockDriverState
*bs
,
443 QEMUSnapshotInfo
*sn_info
);
444 int (*bdrv_snapshot_goto
)(BlockDriverState
*bs
,
445 const char *snapshot_id
);
446 int (*bdrv_snapshot_delete
)(BlockDriverState
*bs
,
447 const char *snapshot_id
,
450 int (*bdrv_snapshot_list
)(BlockDriverState
*bs
,
451 QEMUSnapshotInfo
**psn_info
);
452 int (*bdrv_snapshot_load_tmp
)(BlockDriverState
*bs
,
453 const char *snapshot_id
,
456 int (*bdrv_get_info
)(BlockDriverState
*bs
, BlockDriverInfo
*bdi
);
457 ImageInfoSpecific
*(*bdrv_get_specific_info
)(BlockDriverState
*bs
,
459 BlockStatsSpecific
*(*bdrv_get_specific_stats
)(BlockDriverState
*bs
);
461 int coroutine_fn (*bdrv_save_vmstate
)(BlockDriverState
*bs
,
464 int coroutine_fn (*bdrv_load_vmstate
)(BlockDriverState
*bs
,
468 int (*bdrv_change_backing_file
)(BlockDriverState
*bs
,
469 const char *backing_file
, const char *backing_fmt
);
471 /* removable device specific */
472 bool (*bdrv_is_inserted
)(BlockDriverState
*bs
);
473 void (*bdrv_eject
)(BlockDriverState
*bs
, bool eject_flag
);
474 void (*bdrv_lock_medium
)(BlockDriverState
*bs
, bool locked
);
476 /* to control generic scsi devices */
477 BlockAIOCB
*(*bdrv_aio_ioctl
)(BlockDriverState
*bs
,
478 unsigned long int req
, void *buf
,
479 BlockCompletionFunc
*cb
, void *opaque
);
480 int coroutine_fn (*bdrv_co_ioctl
)(BlockDriverState
*bs
,
481 unsigned long int req
, void *buf
);
483 /* List of options for creating images, terminated by name == NULL */
484 QemuOptsList
*create_opts
;
486 /* List of options for image amend */
487 QemuOptsList
*amend_opts
;
490 * If this driver supports reopening images this contains a
491 * NULL-terminated list of the runtime options that can be
492 * modified. If an option in this list is unspecified during
493 * reopen then it _must_ be reset to its default value or return
496 const char *const *mutable_opts
;
499 * Returns 0 for completed check, -errno for internal errors.
500 * The check results are stored in result.
502 int coroutine_fn (*bdrv_co_check
)(BlockDriverState
*bs
,
503 BdrvCheckResult
*result
,
506 void (*bdrv_debug_event
)(BlockDriverState
*bs
, BlkdebugEvent event
);
508 /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */
509 int (*bdrv_debug_breakpoint
)(BlockDriverState
*bs
, const char *event
,
511 int (*bdrv_debug_remove_breakpoint
)(BlockDriverState
*bs
,
513 int (*bdrv_debug_resume
)(BlockDriverState
*bs
, const char *tag
);
514 bool (*bdrv_debug_is_suspended
)(BlockDriverState
*bs
, const char *tag
);
516 void (*bdrv_refresh_limits
)(BlockDriverState
*bs
, Error
**errp
);
519 * Returns 1 if newly created images are guaranteed to contain only
520 * zeros, 0 otherwise.
522 int (*bdrv_has_zero_init
)(BlockDriverState
*bs
);
524 /* Remove fd handlers, timers, and other event loop callbacks so the event
525 * loop is no longer in use. Called with no in-flight requests and in
526 * depth-first traversal order with parents before child nodes.
528 void (*bdrv_detach_aio_context
)(BlockDriverState
*bs
);
530 /* Add fd handlers, timers, and other event loop callbacks so I/O requests
531 * can be processed again. Called with no in-flight requests and in
532 * depth-first traversal order with child nodes before parent nodes.
534 void (*bdrv_attach_aio_context
)(BlockDriverState
*bs
,
535 AioContext
*new_context
);
537 /* io queue for linux-aio */
538 void (*bdrv_io_plug
)(BlockDriverState
*bs
);
539 void (*bdrv_io_unplug
)(BlockDriverState
*bs
);
542 * Try to get @bs's logical and physical block size.
543 * On success, store them in @bsz and return zero.
544 * On failure, return negative errno.
546 int (*bdrv_probe_blocksizes
)(BlockDriverState
*bs
, BlockSizes
*bsz
);
548 * Try to get @bs's geometry (cyls, heads, sectors)
549 * On success, store them in @geo and return 0.
550 * On failure return -errno.
551 * Only drivers that want to override guest geometry implement this
552 * callback; see hd_geometry_guess().
554 int (*bdrv_probe_geometry
)(BlockDriverState
*bs
, HDGeometry
*geo
);
557 * bdrv_co_drain_begin is called if implemented in the beginning of a
558 * drain operation to drain and stop any internal sources of requests in
560 * bdrv_co_drain_end is called if implemented at the end of the drain.
562 * They should be used by the driver to e.g. manage scheduled I/O
563 * requests, or toggle an internal state. After the end of the drain new
564 * requests will continue normally.
566 void coroutine_fn (*bdrv_co_drain_begin
)(BlockDriverState
*bs
);
567 void coroutine_fn (*bdrv_co_drain_end
)(BlockDriverState
*bs
);
569 void (*bdrv_add_child
)(BlockDriverState
*parent
, BlockDriverState
*child
,
571 void (*bdrv_del_child
)(BlockDriverState
*parent
, BdrvChild
*child
,
575 * Informs the block driver that a permission change is intended. The
576 * driver checks whether the change is permissible and may take other
577 * preparations for the change (e.g. get file system locks). This operation
578 * is always followed either by a call to either .bdrv_set_perm or
579 * .bdrv_abort_perm_update.
581 * Checks whether the requested set of cumulative permissions in @perm
582 * can be granted for accessing @bs and whether no other users are using
583 * permissions other than those given in @shared (both arguments take
584 * BLK_PERM_* bitmasks).
586 * If both conditions are met, 0 is returned. Otherwise, -errno is returned
587 * and errp is set to an error describing the conflict.
589 int (*bdrv_check_perm
)(BlockDriverState
*bs
, uint64_t perm
,
590 uint64_t shared
, Error
**errp
);
593 * Called to inform the driver that the set of cumulative set of used
594 * permissions for @bs has changed to @perm, and the set of sharable
595 * permission to @shared. The driver can use this to propagate changes to
596 * its children (i.e. request permissions only if a parent actually needs
599 * This function is only invoked after bdrv_check_perm(), so block drivers
600 * may rely on preparations made in their .bdrv_check_perm implementation.
602 void (*bdrv_set_perm
)(BlockDriverState
*bs
, uint64_t perm
, uint64_t shared
);
605 * Called to inform the driver that after a previous bdrv_check_perm()
606 * call, the permission update is not performed and any preparations made
607 * for it (e.g. taken file locks) need to be undone.
609 * This function can be called even for nodes that never saw a
610 * bdrv_check_perm() call. It is a no-op then.
612 void (*bdrv_abort_perm_update
)(BlockDriverState
*bs
);
615 * Returns in @nperm and @nshared the permissions that the driver for @bs
616 * needs on its child @c, based on the cumulative permissions requested by
617 * the parents in @parent_perm and @parent_shared.
619 * If @c is NULL, return the permissions for attaching a new child for the
620 * given @child_class and @role.
622 * If @reopen_queue is non-NULL, don't return the currently needed
623 * permissions, but those that will be needed after applying the
626 void (*bdrv_child_perm
)(BlockDriverState
*bs
, BdrvChild
*c
,
628 BlockReopenQueue
*reopen_queue
,
629 uint64_t parent_perm
, uint64_t parent_shared
,
630 uint64_t *nperm
, uint64_t *nshared
);
632 bool (*bdrv_supports_persistent_dirty_bitmap
)(BlockDriverState
*bs
);
633 bool (*bdrv_co_can_store_new_dirty_bitmap
)(BlockDriverState
*bs
,
635 uint32_t granularity
,
637 int (*bdrv_co_remove_persistent_dirty_bitmap
)(BlockDriverState
*bs
,
642 * Register/unregister a buffer for I/O. For example, when the driver is
643 * interested to know the memory areas that will later be used in iovs, so
644 * that it can do IOMMU mapping with VFIO etc., in order to get better
645 * performance. In the case of VFIO drivers, this callback is used to do
646 * DMA mapping for hot buffers.
648 void (*bdrv_register_buf
)(BlockDriverState
*bs
, void *host
, size_t size
);
649 void (*bdrv_unregister_buf
)(BlockDriverState
*bs
, void *host
);
650 QLIST_ENTRY(BlockDriver
) list
;
652 /* Pointer to a NULL-terminated array of names of strong options
653 * that can be specified for bdrv_open(). A strong option is one
654 * that changes the data of a BDS.
655 * If this pointer is NULL, the array is considered empty.
656 * "filename" and "driver" are always considered strong. */
657 const char *const *strong_runtime_opts
;
660 static inline bool block_driver_can_compress(BlockDriver
*drv
)
662 return drv
->bdrv_co_pwritev_compressed
||
663 drv
->bdrv_co_pwritev_compressed_part
;
666 typedef struct BlockLimits
{
667 /* Alignment requirement, in bytes, for offset/length of I/O
668 * requests. Must be a power of 2 less than INT_MAX; defaults to
669 * 1 for drivers with modern byte interfaces, and to 512
671 uint32_t request_alignment
;
673 /* Maximum number of bytes that can be discarded at once (since it
674 * is signed, it must be < 2G, if set). Must be multiple of
675 * pdiscard_alignment, but need not be power of 2. May be 0 if no
676 * inherent 32-bit limit */
677 int32_t max_pdiscard
;
679 /* Optimal alignment for discard requests in bytes. A power of 2
680 * is best but not mandatory. Must be a multiple of
681 * bl.request_alignment, and must be less than max_pdiscard if
682 * that is set. May be 0 if bl.request_alignment is good enough */
683 uint32_t pdiscard_alignment
;
685 /* Maximum number of bytes that can zeroized at once (since it is
686 * signed, it must be < 2G, if set). Must be multiple of
687 * pwrite_zeroes_alignment. May be 0 if no inherent 32-bit limit */
688 int32_t max_pwrite_zeroes
;
690 /* Optimal alignment for write zeroes requests in bytes. A power
691 * of 2 is best but not mandatory. Must be a multiple of
692 * bl.request_alignment, and must be less than max_pwrite_zeroes
693 * if that is set. May be 0 if bl.request_alignment is good
695 uint32_t pwrite_zeroes_alignment
;
697 /* Optimal transfer length in bytes. A power of 2 is best but not
698 * mandatory. Must be a multiple of bl.request_alignment, or 0 if
699 * no preferred size */
700 uint32_t opt_transfer
;
702 /* Maximal transfer length in bytes. Need not be power of 2, but
703 * must be multiple of opt_transfer and bl.request_alignment, or 0
704 * for no 32-bit limit. For now, anything larger than INT_MAX is
706 uint32_t max_transfer
;
708 /* Maximal hardware transfer length in bytes. Applies whenever
709 * transfers to the device bypass the kernel I/O scheduler, for
710 * example with SG_IO. If larger than max_transfer or if zero,
711 * blk_get_max_hw_transfer will fall back to max_transfer.
713 uint64_t max_hw_transfer
;
715 /* memory alignment, in bytes so that no bounce buffer is needed */
716 size_t min_mem_alignment
;
718 /* memory alignment, in bytes, for bounce buffer */
719 size_t opt_mem_alignment
;
721 /* maximum number of iovec elements */
725 typedef struct BdrvOpBlocker BdrvOpBlocker
;
727 typedef struct BdrvAioNotifier
{
728 void (*attached_aio_context
)(AioContext
*new_context
, void *opaque
);
729 void (*detach_aio_context
)(void *opaque
);
734 QLIST_ENTRY(BdrvAioNotifier
) list
;
737 struct BdrvChildClass
{
738 /* If true, bdrv_replace_node() doesn't change the node this BdrvChild
742 /* If true, the parent is a BlockDriverState and bdrv_next_all_states()
743 * will return it. This information is used for drain_all, where every node
744 * will be drained separately, so the drain only needs to be propagated to
745 * non-BDS parents. */
748 void (*inherit_options
)(BdrvChildRole role
, bool parent_is_format
,
749 int *child_flags
, QDict
*child_options
,
750 int parent_flags
, QDict
*parent_options
);
752 void (*change_media
)(BdrvChild
*child
, bool load
);
753 void (*resize
)(BdrvChild
*child
);
755 /* Returns a name that is supposedly more useful for human users than the
756 * node name for identifying the node in question (in particular, a BB
757 * name), or NULL if the parent can't provide a better name. */
758 const char *(*get_name
)(BdrvChild
*child
);
760 /* Returns a malloced string that describes the parent of the child for a
761 * human reader. This could be a node-name, BlockBackend name, qdev ID or
762 * QOM path of the device owning the BlockBackend, job type and ID etc. The
763 * caller is responsible for freeing the memory. */
764 char *(*get_parent_desc
)(BdrvChild
*child
);
767 * If this pair of functions is implemented, the parent doesn't issue new
768 * requests after returning from .drained_begin() until .drained_end() is
771 * These functions must not change the graph (and therefore also must not
772 * call aio_poll(), which could change the graph indirectly).
774 * If drained_end() schedules background operations, it must atomically
775 * increment *drained_end_counter for each such operation and atomically
776 * decrement it once the operation has settled.
778 * Note that this can be nested. If drained_begin() was called twice, new
779 * I/O is allowed only after drained_end() was called twice, too.
781 void (*drained_begin
)(BdrvChild
*child
);
782 void (*drained_end
)(BdrvChild
*child
, int *drained_end_counter
);
785 * Returns whether the parent has pending requests for the child. This
786 * callback is polled after .drained_begin() has been called until all
787 * activity on the child has stopped.
789 bool (*drained_poll
)(BdrvChild
*child
);
791 /* Notifies the parent that the child has been activated/inactivated (e.g.
792 * when migration is completing) and it can start/stop requesting
793 * permissions and doing I/O on it. */
794 void (*activate
)(BdrvChild
*child
, Error
**errp
);
795 int (*inactivate
)(BdrvChild
*child
);
797 void (*attach
)(BdrvChild
*child
);
798 void (*detach
)(BdrvChild
*child
);
800 /* Notifies the parent that the filename of its child has changed (e.g.
801 * because the direct child was removed from the backing chain), so that it
802 * can update its reference. */
803 int (*update_filename
)(BdrvChild
*child
, BlockDriverState
*new_base
,
804 const char *filename
, Error
**errp
);
806 bool (*can_set_aio_ctx
)(BdrvChild
*child
, AioContext
*ctx
,
807 GSList
**ignore
, Error
**errp
);
808 void (*set_aio_ctx
)(BdrvChild
*child
, AioContext
*ctx
, GSList
**ignore
);
810 AioContext
*(*get_parent_aio_context
)(BdrvChild
*child
);
813 extern const BdrvChildClass child_of_bds
;
816 BlockDriverState
*bs
;
818 const BdrvChildClass
*klass
;
823 * Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask)
828 * Permissions that can still be granted to other users of @bs while this
829 * BdrvChild is still attached to it. (BLK_PERM_* bitmask)
831 uint64_t shared_perm
;
834 * This link is frozen: the child can neither be replaced nor
835 * detached from the parent.
840 * How many times the parent of this child has been drained
841 * (through klass->drained_*).
842 * Usually, this is equal to bs->quiesce_counter (potentially
843 * reduced by bdrv_drain_all_count). It may differ while the
844 * child is entering or leaving a drained section.
846 int parent_quiesce_counter
;
848 QLIST_ENTRY(BdrvChild
) next
;
849 QLIST_ENTRY(BdrvChild
) next_parent
;
853 * Allows bdrv_co_block_status() to cache one data region for a
856 * @valid: Whether the cache is valid (should be accessed with atomic
857 * functions so this can be reset by RCU readers)
858 * @data_start: Offset where we know (or strongly assume) is data
859 * @data_end: Offset where the data region ends (which is not necessarily
860 * the start of a zeroed region)
862 typedef struct BdrvBlockStatusCache
{
868 } BdrvBlockStatusCache
;
870 struct BlockDriverState
{
871 /* Protected by big QEMU lock or read-only after opening. No special
872 * locking needed during I/O...
874 int open_flags
; /* flags used to open the file, re-used for re-open */
875 bool encrypted
; /* if true, the media is encrypted */
876 bool sg
; /* if true, the device is a /dev/sg* */
877 bool probed
; /* if true, format was probed rather than specified */
878 bool force_share
; /* if true, always allow all shared permissions */
879 bool implicit
; /* if true, this filter node was automatically inserted */
881 BlockDriver
*drv
; /* NULL means no media */
884 AioContext
*aio_context
; /* event loop used for fd handlers, timers, etc */
885 /* long-running tasks intended to always use the same AioContext as this
886 * BDS may register themselves in this list to be notified of changes
887 * regarding this BDS's context */
888 QLIST_HEAD(, BdrvAioNotifier
) aio_notifiers
;
889 bool walking_aio_notifiers
; /* to make removal during iteration safe */
891 char filename
[PATH_MAX
];
893 * If not empty, this image is a diff in relation to backing_file.
894 * Note that this is the name given in the image header and
895 * therefore may or may not be equal to .backing->bs->filename.
896 * If this field contains a relative path, it is to be resolved
897 * relatively to the overlay's location.
899 char backing_file
[PATH_MAX
];
901 * The backing filename indicated by the image header. Contrary
902 * to backing_file, if we ever open this file, auto_backing_file
903 * is replaced by the resulting BDS's filename (i.e. after a
904 * bdrv_refresh_filename() run).
906 char auto_backing_file
[PATH_MAX
];
907 char backing_format
[16]; /* if non-zero and backing_file exists */
909 QDict
*full_open_options
;
910 char exact_filename
[PATH_MAX
];
919 * Flags honored during pread
921 unsigned int supported_read_flags
;
922 /* Flags honored during pwrite (so far: BDRV_REQ_FUA,
923 * BDRV_REQ_WRITE_UNCHANGED).
924 * If a driver does not support BDRV_REQ_WRITE_UNCHANGED, those
925 * writes will be issued as normal writes without the flag set.
926 * This is important to note for drivers that do not explicitly
927 * request a WRITE permission for their children and instead take
928 * the same permissions as their parent did (this is commonly what
929 * block filters do). Such drivers have to be aware that the
930 * parent may have taken a WRITE_UNCHANGED permission only and is
931 * issuing such requests. Drivers either must make sure that
932 * these requests do not result in plain WRITE accesses (usually
933 * by supporting BDRV_REQ_WRITE_UNCHANGED, and then forwarding
934 * every incoming write request as-is, including potentially that
935 * flag), or they have to explicitly take the WRITE permission for
937 unsigned int supported_write_flags
;
938 /* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA,
939 * BDRV_REQ_MAY_UNMAP, BDRV_REQ_WRITE_UNCHANGED) */
940 unsigned int supported_zero_flags
;
942 * Flags honoured during truncate (so far: BDRV_REQ_ZERO_WRITE).
944 * If BDRV_REQ_ZERO_WRITE is given, the truncate operation must make sure
945 * that any added space reads as all zeros. If this can't be guaranteed,
946 * the operation must fail.
948 unsigned int supported_truncate_flags
;
950 /* the following member gives a name to every node on the bs graph. */
952 /* element of the list of named nodes building the graph */
953 QTAILQ_ENTRY(BlockDriverState
) node_list
;
954 /* element of the list of all BlockDriverStates (all_bdrv_states) */
955 QTAILQ_ENTRY(BlockDriverState
) bs_list
;
956 /* element of the list of monitor-owned BDS */
957 QTAILQ_ENTRY(BlockDriverState
) monitor_list
;
960 /* operation blockers */
961 QLIST_HEAD(, BdrvOpBlocker
) op_blockers
[BLOCK_OP_TYPE_MAX
];
963 /* The node that this node inherited default options from (and a reopen on
964 * which can affect this node by changing these defaults). This is always a
965 * parent node of this node. */
966 BlockDriverState
*inherits_from
;
967 QLIST_HEAD(, BdrvChild
) children
;
968 QLIST_HEAD(, BdrvChild
) parents
;
971 QDict
*explicit_options
;
972 BlockdevDetectZeroesOptions detect_zeroes
;
974 /* The error object in use for blocking operations on backing_hd */
975 Error
*backing_blocker
;
977 /* Protected by AioContext lock */
979 /* If we are reading a disk image, give its size in sectors.
980 * Generally read-only; it is written to by load_snapshot and
981 * save_snaphost, but the block layer is quiescent during those.
983 int64_t total_sectors
;
985 /* threshold limit for writes, in bytes. "High water mark". */
986 uint64_t write_threshold_offset
;
988 /* Writing to the list requires the BQL _and_ the dirty_bitmap_mutex.
989 * Reading from the list can be done with either the BQL or the
990 * dirty_bitmap_mutex. Modifying a bitmap only requires
991 * dirty_bitmap_mutex. */
992 QemuMutex dirty_bitmap_mutex
;
993 QLIST_HEAD(, BdrvDirtyBitmap
) dirty_bitmaps
;
995 /* Offset after the highest byte written to */
996 Stat64 wr_highest_offset
;
998 /* If true, copy read backing sectors into image. Can be >1 if more
999 * than one client has requested copy-on-read. Accessed with atomic
1004 /* number of in-flight requests; overall and serialising.
1005 * Accessed with atomic ops.
1007 unsigned int in_flight
;
1008 unsigned int serialising_in_flight
;
1010 /* counter for nested bdrv_io_plug.
1011 * Accessed with atomic ops.
1013 unsigned io_plugged
;
1015 /* do we need to tell the quest if we have a volatile write cache? */
1016 int enable_write_cache
;
1018 /* Accessed with atomic ops. */
1019 int quiesce_counter
;
1020 int recursive_quiesce_counter
;
1022 unsigned int write_gen
; /* Current data generation */
1024 /* Protected by reqs_lock. */
1026 QLIST_HEAD(, BdrvTrackedRequest
) tracked_requests
;
1027 CoQueue flush_queue
; /* Serializing flush queue */
1028 bool active_flush_req
; /* Flush request in flight? */
1030 /* Only read/written by whoever has set active_flush_req to true. */
1031 unsigned int flushed_gen
; /* Flushed write generation */
1033 /* BdrvChild links to this node may never be frozen */
1036 /* Lock for block-status cache RCU writers */
1037 CoMutex bsc_modify_lock
;
1038 /* Always non-NULL, but must only be dereferenced under an RCU read guard */
1039 BdrvBlockStatusCache
*block_status_cache
;
1042 struct BlockBackendRootState
{
1044 BlockdevDetectZeroesOptions detect_zeroes
;
1047 typedef enum BlockMirrorBackingMode
{
1048 /* Reuse the existing backing chain from the source for the target.
1049 * - sync=full: Set backing BDS to NULL.
1050 * - sync=top: Use source's backing BDS.
1051 * - sync=none: Use source as the backing BDS. */
1052 MIRROR_SOURCE_BACKING_CHAIN
,
1054 /* Open the target's backing chain completely anew */
1055 MIRROR_OPEN_BACKING_CHAIN
,
1057 /* Do not change the target's backing BDS after job completion */
1058 MIRROR_LEAVE_BACKING_CHAIN
,
1059 } BlockMirrorBackingMode
;
1062 /* Essential block drivers which must always be statically linked into qemu, and
1063 * which therefore can be accessed without using bdrv_find_format() */
1064 extern BlockDriver bdrv_file
;
1065 extern BlockDriver bdrv_raw
;
1066 extern BlockDriver bdrv_qcow2
;
1068 int coroutine_fn
bdrv_co_preadv(BdrvChild
*child
,
1069 int64_t offset
, int64_t bytes
, QEMUIOVector
*qiov
,
1070 BdrvRequestFlags flags
);
1071 int coroutine_fn
bdrv_co_preadv_part(BdrvChild
*child
,
1072 int64_t offset
, int64_t bytes
,
1073 QEMUIOVector
*qiov
, size_t qiov_offset
, BdrvRequestFlags flags
);
1074 int coroutine_fn
bdrv_co_pwritev(BdrvChild
*child
,
1075 int64_t offset
, int64_t bytes
, QEMUIOVector
*qiov
,
1076 BdrvRequestFlags flags
);
1077 int coroutine_fn
bdrv_co_pwritev_part(BdrvChild
*child
,
1078 int64_t offset
, int64_t bytes
,
1079 QEMUIOVector
*qiov
, size_t qiov_offset
, BdrvRequestFlags flags
);
1081 static inline int coroutine_fn
bdrv_co_pread(BdrvChild
*child
,
1082 int64_t offset
, unsigned int bytes
, void *buf
, BdrvRequestFlags flags
)
1084 QEMUIOVector qiov
= QEMU_IOVEC_INIT_BUF(qiov
, buf
, bytes
);
1086 return bdrv_co_preadv(child
, offset
, bytes
, &qiov
, flags
);
1089 static inline int coroutine_fn
bdrv_co_pwrite(BdrvChild
*child
,
1090 int64_t offset
, unsigned int bytes
, void *buf
, BdrvRequestFlags flags
)
1092 QEMUIOVector qiov
= QEMU_IOVEC_INIT_BUF(qiov
, buf
, bytes
);
1094 return bdrv_co_pwritev(child
, offset
, bytes
, &qiov
, flags
);
1097 extern unsigned int bdrv_drain_all_count
;
1098 void bdrv_apply_subtree_drain(BdrvChild
*child
, BlockDriverState
*new_parent
);
1099 void bdrv_unapply_subtree_drain(BdrvChild
*child
, BlockDriverState
*old_parent
);
1101 bool coroutine_fn
bdrv_make_request_serialising(BdrvTrackedRequest
*req
,
1103 BdrvTrackedRequest
*coroutine_fn
bdrv_co_get_self_request(BlockDriverState
*bs
);
1105 int get_tmp_filename(char *filename
, int size
);
1106 BlockDriver
*bdrv_probe_all(const uint8_t *buf
, int buf_size
,
1107 const char *filename
);
1109 void bdrv_parse_filename_strip_prefix(const char *filename
, const char *prefix
,
1112 bool bdrv_backing_overridden(BlockDriverState
*bs
);
1116 * bdrv_add_aio_context_notifier:
1118 * If a long-running job intends to be always run in the same AioContext as a
1119 * certain BDS, it may use this function to be notified of changes regarding the
1120 * association of the BDS to an AioContext.
1122 * attached_aio_context() is called after the target BDS has been attached to a
1123 * new AioContext; detach_aio_context() is called before the target BDS is being
1124 * detached from its old AioContext.
1126 void bdrv_add_aio_context_notifier(BlockDriverState
*bs
,
1127 void (*attached_aio_context
)(AioContext
*new_context
, void *opaque
),
1128 void (*detach_aio_context
)(void *opaque
), void *opaque
);
1131 * bdrv_remove_aio_context_notifier:
1133 * Unsubscribe of change notifications regarding the BDS's AioContext. The
1134 * parameters given here have to be the same as those given to
1135 * bdrv_add_aio_context_notifier().
1137 void bdrv_remove_aio_context_notifier(BlockDriverState
*bs
,
1138 void (*aio_context_attached
)(AioContext
*,
1140 void (*aio_context_detached
)(void *),
1145 * @bs: The BlockDriverState for which an I/O operation has been completed.
1147 * Wake up the main thread if it is waiting on BDRV_POLL_WHILE. During
1148 * synchronous I/O on a BlockDriverState that is attached to another
1149 * I/O thread, the main thread lets the I/O thread's event loop run,
1150 * waiting for the I/O operation to complete. A bdrv_wakeup will wake
1151 * up the main thread if necessary.
1153 * Manual calls to bdrv_wakeup are rarely necessary, because
1154 * bdrv_dec_in_flight already calls it.
1156 void bdrv_wakeup(BlockDriverState
*bs
);
1159 int is_windows_drive(const char *filename
);
1164 * @job_id: The id of the newly-created job, or %NULL to use the
1165 * device name of @bs.
1166 * @bs: Block device to operate on.
1167 * @base: Block device that will become the new base, or %NULL to
1168 * flatten the whole backing file chain onto @bs.
1169 * @backing_file_str: The file name that will be written to @bs as the
1170 * the new backing file if the job completes. Ignored if @base is %NULL.
1171 * @creation_flags: Flags that control the behavior of the Job lifetime.
1172 * See @BlockJobCreateFlags
1173 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
1174 * @on_error: The action to take upon error.
1175 * @filter_node_name: The node name that should be assigned to the filter
1176 * driver that the stream job inserts into the graph above
1177 * @bs. NULL means that a node name should be autogenerated.
1178 * @errp: Error object.
1180 * Start a streaming operation on @bs. Clusters that are unallocated
1181 * in @bs, but allocated in any image between @base and @bs (both
1182 * exclusive) will be written to @bs. At the end of a successful
1183 * streaming job, the backing file of @bs will be changed to
1184 * @backing_file_str in the written image and to @base in the live
1187 void stream_start(const char *job_id
, BlockDriverState
*bs
,
1188 BlockDriverState
*base
, const char *backing_file_str
,
1189 BlockDriverState
*bottom
,
1190 int creation_flags
, int64_t speed
,
1191 BlockdevOnError on_error
,
1192 const char *filter_node_name
,
1197 * @job_id: The id of the newly-created job, or %NULL to use the
1198 * device name of @bs.
1199 * @bs: Active block device.
1200 * @top: Top block device to be committed.
1201 * @base: Block device that will be written into, and become the new top.
1202 * @creation_flags: Flags that control the behavior of the Job lifetime.
1203 * See @BlockJobCreateFlags
1204 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
1205 * @on_error: The action to take upon error.
1206 * @backing_file_str: String to use as the backing file in @top's overlay
1207 * @filter_node_name: The node name that should be assigned to the filter
1208 * driver that the commit job inserts into the graph above @top. NULL means
1209 * that a node name should be autogenerated.
1210 * @errp: Error object.
1213 void commit_start(const char *job_id
, BlockDriverState
*bs
,
1214 BlockDriverState
*base
, BlockDriverState
*top
,
1215 int creation_flags
, int64_t speed
,
1216 BlockdevOnError on_error
, const char *backing_file_str
,
1217 const char *filter_node_name
, Error
**errp
);
1219 * commit_active_start:
1220 * @job_id: The id of the newly-created job, or %NULL to use the
1221 * device name of @bs.
1222 * @bs: Active block device to be committed.
1223 * @base: Block device that will be written into, and become the new top.
1224 * @creation_flags: Flags that control the behavior of the Job lifetime.
1225 * See @BlockJobCreateFlags
1226 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
1227 * @on_error: The action to take upon error.
1228 * @filter_node_name: The node name that should be assigned to the filter
1229 * driver that the commit job inserts into the graph above @bs. NULL means that
1230 * a node name should be autogenerated.
1231 * @cb: Completion function for the job.
1232 * @opaque: Opaque pointer value passed to @cb.
1233 * @auto_complete: Auto complete the job.
1234 * @errp: Error object.
1237 BlockJob
*commit_active_start(const char *job_id
, BlockDriverState
*bs
,
1238 BlockDriverState
*base
, int creation_flags
,
1239 int64_t speed
, BlockdevOnError on_error
,
1240 const char *filter_node_name
,
1241 BlockCompletionFunc
*cb
, void *opaque
,
1242 bool auto_complete
, Error
**errp
);
1245 * @job_id: The id of the newly-created job, or %NULL to use the
1246 * device name of @bs.
1247 * @bs: Block device to operate on.
1248 * @target: Block device to write to.
1249 * @replaces: Block graph node name to replace once the mirror is done. Can
1250 * only be used when full mirroring is selected.
1251 * @creation_flags: Flags that control the behavior of the Job lifetime.
1252 * See @BlockJobCreateFlags
1253 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
1254 * @granularity: The chosen granularity for the dirty bitmap.
1255 * @buf_size: The amount of data that can be in flight at one time.
1256 * @mode: Whether to collapse all images in the chain to the target.
1257 * @backing_mode: How to establish the target's backing chain after completion.
1258 * @zero_target: Whether the target should be explicitly zero-initialized
1259 * @on_source_error: The action to take upon error reading from the source.
1260 * @on_target_error: The action to take upon error writing to the target.
1261 * @unmap: Whether to unmap target where source sectors only contain zeroes.
1262 * @filter_node_name: The node name that should be assigned to the filter
1263 * driver that the mirror job inserts into the graph above @bs. NULL means that
1264 * a node name should be autogenerated.
1265 * @copy_mode: When to trigger writes to the target.
1266 * @errp: Error object.
1268 * Start a mirroring operation on @bs. Clusters that are allocated
1269 * in @bs will be written to @target until the job is cancelled or
1270 * manually completed. At the end of a successful mirroring job,
1271 * @bs will be switched to read from @target.
1273 void mirror_start(const char *job_id
, BlockDriverState
*bs
,
1274 BlockDriverState
*target
, const char *replaces
,
1275 int creation_flags
, int64_t speed
,
1276 uint32_t granularity
, int64_t buf_size
,
1277 MirrorSyncMode mode
, BlockMirrorBackingMode backing_mode
,
1279 BlockdevOnError on_source_error
,
1280 BlockdevOnError on_target_error
,
1281 bool unmap
, const char *filter_node_name
,
1282 MirrorCopyMode copy_mode
, Error
**errp
);
1285 * backup_job_create:
1286 * @job_id: The id of the newly-created job, or %NULL to use the
1287 * device name of @bs.
1288 * @bs: Block device to operate on.
1289 * @target: Block device to write to.
1290 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
1291 * @sync_mode: What parts of the disk image should be copied to the destination.
1292 * @sync_bitmap: The dirty bitmap if sync_mode is 'bitmap' or 'incremental'
1293 * @bitmap_mode: The bitmap synchronization policy to use.
1294 * @perf: Performance options. All actual fields assumed to be present,
1295 * all ".has_*" fields are ignored.
1296 * @on_source_error: The action to take upon error reading from the source.
1297 * @on_target_error: The action to take upon error writing to the target.
1298 * @creation_flags: Flags that control the behavior of the Job lifetime.
1299 * See @BlockJobCreateFlags
1300 * @cb: Completion function for the job.
1301 * @opaque: Opaque pointer value passed to @cb.
1302 * @txn: Transaction that this job is part of (may be NULL).
1304 * Create a backup operation on @bs. Clusters in @bs are written to @target
1305 * until the job is cancelled or manually completed.
1307 BlockJob
*backup_job_create(const char *job_id
, BlockDriverState
*bs
,
1308 BlockDriverState
*target
, int64_t speed
,
1309 MirrorSyncMode sync_mode
,
1310 BdrvDirtyBitmap
*sync_bitmap
,
1311 BitmapSyncMode bitmap_mode
,
1313 const char *filter_node_name
,
1315 BlockdevOnError on_source_error
,
1316 BlockdevOnError on_target_error
,
1318 BlockCompletionFunc
*cb
, void *opaque
,
1319 JobTxn
*txn
, Error
**errp
);
1321 BdrvChild
*bdrv_root_attach_child(BlockDriverState
*child_bs
,
1322 const char *child_name
,
1323 const BdrvChildClass
*child_class
,
1324 BdrvChildRole child_role
,
1325 uint64_t perm
, uint64_t shared_perm
,
1326 void *opaque
, Error
**errp
);
1327 void bdrv_root_unref_child(BdrvChild
*child
);
1329 void bdrv_get_cumulative_perm(BlockDriverState
*bs
, uint64_t *perm
,
1330 uint64_t *shared_perm
);
1333 * Sets a BdrvChild's permissions. Avoid if the parent is a BDS; use
1334 * bdrv_child_refresh_perms() instead and make the parent's
1335 * .bdrv_child_perm() implementation return the correct values.
1337 int bdrv_child_try_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
,
1341 * Calls bs->drv->bdrv_child_perm() and updates the child's permission
1342 * masks with the result.
1343 * Drivers should invoke this function whenever an event occurs that
1344 * makes their .bdrv_child_perm() implementation return different
1345 * values than before, but which will not result in the block layer
1346 * automatically refreshing the permissions.
1348 int bdrv_child_refresh_perms(BlockDriverState
*bs
, BdrvChild
*c
, Error
**errp
);
1350 bool bdrv_recurse_can_replace(BlockDriverState
*bs
,
1351 BlockDriverState
*to_replace
);
1354 * Default implementation for BlockDriver.bdrv_child_perm() that can
1355 * be used by block filters and image formats, as long as they use the
1356 * child_of_bds child class and set an appropriate BdrvChildRole.
1358 void bdrv_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
1359 BdrvChildRole role
, BlockReopenQueue
*reopen_queue
,
1360 uint64_t perm
, uint64_t shared
,
1361 uint64_t *nperm
, uint64_t *nshared
);
1363 const char *bdrv_get_parent_name(const BlockDriverState
*bs
);
1364 void blk_dev_change_media_cb(BlockBackend
*blk
, bool load
, Error
**errp
);
1365 bool blk_dev_has_removable_media(BlockBackend
*blk
);
1366 bool blk_dev_has_tray(BlockBackend
*blk
);
1367 void blk_dev_eject_request(BlockBackend
*blk
, bool force
);
1368 bool blk_dev_is_tray_open(BlockBackend
*blk
);
1369 bool blk_dev_is_medium_locked(BlockBackend
*blk
);
1371 void bdrv_set_dirty(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
);
1373 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap
*bitmap
, HBitmap
**out
);
1374 void bdrv_restore_dirty_bitmap(BdrvDirtyBitmap
*bitmap
, HBitmap
*backup
);
1375 bool bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap
*dest
,
1376 const BdrvDirtyBitmap
*src
,
1377 HBitmap
**backup
, bool lock
);
1379 void bdrv_inc_in_flight(BlockDriverState
*bs
);
1380 void bdrv_dec_in_flight(BlockDriverState
*bs
);
1382 void blockdev_close_all_bdrv_states(void);
1384 int coroutine_fn
bdrv_co_copy_range_from(BdrvChild
*src
, int64_t src_offset
,
1385 BdrvChild
*dst
, int64_t dst_offset
,
1387 BdrvRequestFlags read_flags
,
1388 BdrvRequestFlags write_flags
);
1389 int coroutine_fn
bdrv_co_copy_range_to(BdrvChild
*src
, int64_t src_offset
,
1390 BdrvChild
*dst
, int64_t dst_offset
,
1392 BdrvRequestFlags read_flags
,
1393 BdrvRequestFlags write_flags
);
1395 int refresh_total_sectors(BlockDriverState
*bs
, int64_t hint
);
1397 void bdrv_set_monitor_owned(BlockDriverState
*bs
);
1398 BlockDriverState
*bds_tree_init(QDict
*bs_opts
, Error
**errp
);
1401 * Simple implementation of bdrv_co_create_opts for protocol drivers
1402 * which only support creation via opening a file
1403 * (usually existing raw storage device)
1405 int coroutine_fn
bdrv_co_create_opts_simple(BlockDriver
*drv
,
1406 const char *filename
,
1409 extern QemuOptsList bdrv_create_opts_simple
;
1411 BdrvDirtyBitmap
*block_dirty_bitmap_lookup(const char *node
,
1413 BlockDriverState
**pbs
,
1415 BdrvDirtyBitmap
*block_dirty_bitmap_merge(const char *node
, const char *target
,
1416 BlockDirtyBitmapMergeSourceList
*bms
,
1417 HBitmap
**backup
, Error
**errp
);
1418 BdrvDirtyBitmap
*block_dirty_bitmap_remove(const char *node
, const char *name
,
1420 BlockDriverState
**bitmap_bs
,
1423 BdrvChild
*bdrv_cow_child(BlockDriverState
*bs
);
1424 BdrvChild
*bdrv_filter_child(BlockDriverState
*bs
);
1425 BdrvChild
*bdrv_filter_or_cow_child(BlockDriverState
*bs
);
1426 BdrvChild
*bdrv_primary_child(BlockDriverState
*bs
);
1427 BlockDriverState
*bdrv_skip_implicit_filters(BlockDriverState
*bs
);
1428 BlockDriverState
*bdrv_skip_filters(BlockDriverState
*bs
);
1429 BlockDriverState
*bdrv_backing_chain_next(BlockDriverState
*bs
);
1431 static inline BlockDriverState
*child_bs(BdrvChild
*child
)
1433 return child
? child
->bs
: NULL
;
1436 static inline BlockDriverState
*bdrv_cow_bs(BlockDriverState
*bs
)
1438 return child_bs(bdrv_cow_child(bs
));
1441 static inline BlockDriverState
*bdrv_filter_bs(BlockDriverState
*bs
)
1443 return child_bs(bdrv_filter_child(bs
));
1446 static inline BlockDriverState
*bdrv_filter_or_cow_bs(BlockDriverState
*bs
)
1448 return child_bs(bdrv_filter_or_cow_child(bs
));
1451 static inline BlockDriverState
*bdrv_primary_bs(BlockDriverState
*bs
)
1453 return child_bs(bdrv_primary_child(bs
));
1457 * End all quiescent sections started by bdrv_drain_all_begin(). This is
1458 * needed when deleting a BDS before bdrv_drain_all_end() is called.
1460 * NOTE: this is an internal helper for bdrv_close() *only*. No one else
1463 void bdrv_drain_all_end_quiesce(BlockDriverState
*bs
);
1466 * Check whether the given offset is in the cached block-status data
1469 * If it is, and @pnum is not NULL, *pnum is set to
1470 * `bsc.data_end - offset`, i.e. how many bytes, starting from
1471 * @offset, are data (according to the cache).
1472 * Otherwise, *pnum is not touched.
1474 bool bdrv_bsc_is_data(BlockDriverState
*bs
, int64_t offset
, int64_t *pnum
);
1477 * If [offset, offset + bytes) overlaps with the currently cached
1478 * block-status region, invalidate the cache.
1480 * (To be used by I/O paths that cause data regions to be zero or
1483 void bdrv_bsc_invalidate_range(BlockDriverState
*bs
,
1484 int64_t offset
, int64_t bytes
);
1487 * Mark the range [offset, offset + bytes) as a data region.
1489 void bdrv_bsc_fill(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
);
1491 #endif /* BLOCK_INT_H */