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 "qemu/option.h"
30 #include "qemu/queue.h"
31 #include "qemu/coroutine.h"
32 #include "qemu/timer.h"
33 #include "qapi-types.h"
34 #include "qemu/hbitmap.h"
35 #include "block/snapshot.h"
36 #include "qemu/main-loop.h"
37 #include "qemu/throttle.h"
39 #define BLOCK_FLAG_ENCRYPT 1
40 #define BLOCK_FLAG_LAZY_REFCOUNTS 8
42 #define BLOCK_OPT_SIZE "size"
43 #define BLOCK_OPT_ENCRYPT "encryption"
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_OBJECT_SIZE "object_size"
58 #define BLOCK_OPT_REFCOUNT_BITS "refcount_bits"
60 #define BLOCK_PROBE_BUF_SIZE 512
62 enum BdrvTrackedRequestType
{
68 typedef struct BdrvTrackedRequest
{
72 enum BdrvTrackedRequestType type
;
75 int64_t overlap_offset
;
76 unsigned int overlap_bytes
;
78 QLIST_ENTRY(BdrvTrackedRequest
) list
;
79 Coroutine
*co
; /* owner, used for deadlock detection */
80 CoQueue wait_queue
; /* coroutines blocked on this request */
82 struct BdrvTrackedRequest
*waiting_for
;
86 const char *format_name
;
89 /* set to true if the BlockDriver is a block filter */
91 /* for snapshots block filter like Quorum can implement the
92 * following recursive callback.
93 * It's purpose is to recurse on the filter children while calling
94 * bdrv_recurse_is_first_non_filter on them.
95 * For a sample implementation look in the future Quorum block filter.
97 bool (*bdrv_recurse_is_first_non_filter
)(BlockDriverState
*bs
,
98 BlockDriverState
*candidate
);
100 int (*bdrv_probe
)(const uint8_t *buf
, int buf_size
, const char *filename
);
101 int (*bdrv_probe_device
)(const char *filename
);
103 /* Any driver implementing this callback is expected to be able to handle
104 * NULL file names in its .bdrv_open() implementation */
105 void (*bdrv_parse_filename
)(const char *filename
, QDict
*options
, Error
**errp
);
106 /* Drivers not implementing bdrv_parse_filename nor bdrv_open should have
107 * this field set to true, except ones that are defined only by their
109 * An example of the last type will be the quorum block driver.
111 bool bdrv_needs_filename
;
113 /* Set if a driver can support backing files */
114 bool supports_backing
;
116 /* For handling image reopen for split or non-split files */
117 int (*bdrv_reopen_prepare
)(BDRVReopenState
*reopen_state
,
118 BlockReopenQueue
*queue
, Error
**errp
);
119 void (*bdrv_reopen_commit
)(BDRVReopenState
*reopen_state
);
120 void (*bdrv_reopen_abort
)(BDRVReopenState
*reopen_state
);
121 void (*bdrv_join_options
)(QDict
*options
, QDict
*old_options
);
123 int (*bdrv_open
)(BlockDriverState
*bs
, QDict
*options
, int flags
,
125 int (*bdrv_file_open
)(BlockDriverState
*bs
, QDict
*options
, int flags
,
127 void (*bdrv_close
)(BlockDriverState
*bs
);
128 int (*bdrv_create
)(const char *filename
, QemuOpts
*opts
, Error
**errp
);
129 int (*bdrv_set_key
)(BlockDriverState
*bs
, const char *key
);
130 int (*bdrv_make_empty
)(BlockDriverState
*bs
);
132 void (*bdrv_refresh_filename
)(BlockDriverState
*bs
, QDict
*options
);
135 BlockAIOCB
*(*bdrv_aio_readv
)(BlockDriverState
*bs
,
136 int64_t sector_num
, QEMUIOVector
*qiov
, int nb_sectors
,
137 BlockCompletionFunc
*cb
, void *opaque
);
138 BlockAIOCB
*(*bdrv_aio_writev
)(BlockDriverState
*bs
,
139 int64_t sector_num
, QEMUIOVector
*qiov
, int nb_sectors
,
140 BlockCompletionFunc
*cb
, void *opaque
);
141 BlockAIOCB
*(*bdrv_aio_flush
)(BlockDriverState
*bs
,
142 BlockCompletionFunc
*cb
, void *opaque
);
143 BlockAIOCB
*(*bdrv_aio_pdiscard
)(BlockDriverState
*bs
,
144 int64_t offset
, int count
,
145 BlockCompletionFunc
*cb
, void *opaque
);
147 int coroutine_fn (*bdrv_co_readv
)(BlockDriverState
*bs
,
148 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
);
149 int coroutine_fn (*bdrv_co_preadv
)(BlockDriverState
*bs
,
150 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
, int flags
);
151 int coroutine_fn (*bdrv_co_writev
)(BlockDriverState
*bs
,
152 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
);
153 int coroutine_fn (*bdrv_co_writev_flags
)(BlockDriverState
*bs
,
154 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
, int flags
);
155 int coroutine_fn (*bdrv_co_pwritev
)(BlockDriverState
*bs
,
156 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
, int flags
);
159 * Efficiently zero a region of the disk image. Typically an image format
160 * would use a compact metadata representation to implement this. This
161 * function pointer may be NULL or return -ENOSUP and .bdrv_co_writev()
162 * will be called instead.
164 int coroutine_fn (*bdrv_co_pwrite_zeroes
)(BlockDriverState
*bs
,
165 int64_t offset
, int count
, BdrvRequestFlags flags
);
166 int coroutine_fn (*bdrv_co_pdiscard
)(BlockDriverState
*bs
,
167 int64_t offset
, int count
);
168 int64_t coroutine_fn (*bdrv_co_get_block_status
)(BlockDriverState
*bs
,
169 int64_t sector_num
, int nb_sectors
, int *pnum
,
170 BlockDriverState
**file
);
173 * Invalidate any cached meta-data.
175 void (*bdrv_invalidate_cache
)(BlockDriverState
*bs
, Error
**errp
);
176 int (*bdrv_inactivate
)(BlockDriverState
*bs
);
179 * Flushes all data for all layers by calling bdrv_co_flush for underlying
180 * layers, if needed. This function is needed for deterministic
181 * synchronization of the flush finishing callback.
183 int coroutine_fn (*bdrv_co_flush
)(BlockDriverState
*bs
);
186 * Flushes all data that was already written to the OS all the way down to
187 * the disk (for example file-posix.c calls fsync()).
189 int coroutine_fn (*bdrv_co_flush_to_disk
)(BlockDriverState
*bs
);
192 * Flushes all internal caches to the OS. The data may still sit in a
193 * writeback cache of the host OS, but it will survive a crash of the qemu
196 int coroutine_fn (*bdrv_co_flush_to_os
)(BlockDriverState
*bs
);
198 const char *protocol_name
;
199 int (*bdrv_truncate
)(BlockDriverState
*bs
, int64_t offset
);
201 int64_t (*bdrv_getlength
)(BlockDriverState
*bs
);
202 bool has_variable_length
;
203 int64_t (*bdrv_get_allocated_file_size
)(BlockDriverState
*bs
);
205 int coroutine_fn (*bdrv_co_pwritev_compressed
)(BlockDriverState
*bs
,
206 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
);
208 int (*bdrv_snapshot_create
)(BlockDriverState
*bs
,
209 QEMUSnapshotInfo
*sn_info
);
210 int (*bdrv_snapshot_goto
)(BlockDriverState
*bs
,
211 const char *snapshot_id
);
212 int (*bdrv_snapshot_delete
)(BlockDriverState
*bs
,
213 const char *snapshot_id
,
216 int (*bdrv_snapshot_list
)(BlockDriverState
*bs
,
217 QEMUSnapshotInfo
**psn_info
);
218 int (*bdrv_snapshot_load_tmp
)(BlockDriverState
*bs
,
219 const char *snapshot_id
,
222 int (*bdrv_get_info
)(BlockDriverState
*bs
, BlockDriverInfo
*bdi
);
223 ImageInfoSpecific
*(*bdrv_get_specific_info
)(BlockDriverState
*bs
);
225 int coroutine_fn (*bdrv_save_vmstate
)(BlockDriverState
*bs
,
228 int coroutine_fn (*bdrv_load_vmstate
)(BlockDriverState
*bs
,
232 int (*bdrv_change_backing_file
)(BlockDriverState
*bs
,
233 const char *backing_file
, const char *backing_fmt
);
235 /* removable device specific */
236 bool (*bdrv_is_inserted
)(BlockDriverState
*bs
);
237 int (*bdrv_media_changed
)(BlockDriverState
*bs
);
238 void (*bdrv_eject
)(BlockDriverState
*bs
, bool eject_flag
);
239 void (*bdrv_lock_medium
)(BlockDriverState
*bs
, bool locked
);
241 /* to control generic scsi devices */
242 BlockAIOCB
*(*bdrv_aio_ioctl
)(BlockDriverState
*bs
,
243 unsigned long int req
, void *buf
,
244 BlockCompletionFunc
*cb
, void *opaque
);
245 int coroutine_fn (*bdrv_co_ioctl
)(BlockDriverState
*bs
,
246 unsigned long int req
, void *buf
);
248 /* List of options for creating images, terminated by name == NULL */
249 QemuOptsList
*create_opts
;
252 * Returns 0 for completed check, -errno for internal errors.
253 * The check results are stored in result.
255 int (*bdrv_check
)(BlockDriverState
* bs
, BdrvCheckResult
*result
,
258 int (*bdrv_amend_options
)(BlockDriverState
*bs
, QemuOpts
*opts
,
259 BlockDriverAmendStatusCB
*status_cb
,
262 void (*bdrv_debug_event
)(BlockDriverState
*bs
, BlkdebugEvent event
);
264 /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */
265 int (*bdrv_debug_breakpoint
)(BlockDriverState
*bs
, const char *event
,
267 int (*bdrv_debug_remove_breakpoint
)(BlockDriverState
*bs
,
269 int (*bdrv_debug_resume
)(BlockDriverState
*bs
, const char *tag
);
270 bool (*bdrv_debug_is_suspended
)(BlockDriverState
*bs
, const char *tag
);
272 void (*bdrv_refresh_limits
)(BlockDriverState
*bs
, Error
**errp
);
275 * Returns 1 if newly created images are guaranteed to contain only
276 * zeros, 0 otherwise.
278 int (*bdrv_has_zero_init
)(BlockDriverState
*bs
);
280 /* Remove fd handlers, timers, and other event loop callbacks so the event
281 * loop is no longer in use. Called with no in-flight requests and in
282 * depth-first traversal order with parents before child nodes.
284 void (*bdrv_detach_aio_context
)(BlockDriverState
*bs
);
286 /* Add fd handlers, timers, and other event loop callbacks so I/O requests
287 * can be processed again. Called with no in-flight requests and in
288 * depth-first traversal order with child nodes before parent nodes.
290 void (*bdrv_attach_aio_context
)(BlockDriverState
*bs
,
291 AioContext
*new_context
);
293 /* io queue for linux-aio */
294 void (*bdrv_io_plug
)(BlockDriverState
*bs
);
295 void (*bdrv_io_unplug
)(BlockDriverState
*bs
);
298 * Try to get @bs's logical and physical block size.
299 * On success, store them in @bsz and return zero.
300 * On failure, return negative errno.
302 int (*bdrv_probe_blocksizes
)(BlockDriverState
*bs
, BlockSizes
*bsz
);
304 * Try to get @bs's geometry (cyls, heads, sectors)
305 * On success, store them in @geo and return 0.
306 * On failure return -errno.
307 * Only drivers that want to override guest geometry implement this
308 * callback; see hd_geometry_guess().
310 int (*bdrv_probe_geometry
)(BlockDriverState
*bs
, HDGeometry
*geo
);
313 * Drain and stop any internal sources of requests in the driver, and
314 * remain so until next I/O callback (e.g. bdrv_co_writev) is called.
316 void (*bdrv_drain
)(BlockDriverState
*bs
);
318 void (*bdrv_add_child
)(BlockDriverState
*parent
, BlockDriverState
*child
,
320 void (*bdrv_del_child
)(BlockDriverState
*parent
, BdrvChild
*child
,
324 * Informs the block driver that a permission change is intended. The
325 * driver checks whether the change is permissible and may take other
326 * preparations for the change (e.g. get file system locks). This operation
327 * is always followed either by a call to either .bdrv_set_perm or
328 * .bdrv_abort_perm_update.
330 * Checks whether the requested set of cumulative permissions in @perm
331 * can be granted for accessing @bs and whether no other users are using
332 * permissions other than those given in @shared (both arguments take
333 * BLK_PERM_* bitmasks).
335 * If both conditions are met, 0 is returned. Otherwise, -errno is returned
336 * and errp is set to an error describing the conflict.
338 int (*bdrv_check_perm
)(BlockDriverState
*bs
, uint64_t perm
,
339 uint64_t shared
, Error
**errp
);
342 * Called to inform the driver that the set of cumulative set of used
343 * permissions for @bs has changed to @perm, and the set of sharable
344 * permission to @shared. The driver can use this to propagate changes to
345 * its children (i.e. request permissions only if a parent actually needs
348 * This function is only invoked after bdrv_check_perm(), so block drivers
349 * may rely on preparations made in their .bdrv_check_perm implementation.
351 void (*bdrv_set_perm
)(BlockDriverState
*bs
, uint64_t perm
, uint64_t shared
);
354 * Called to inform the driver that after a previous bdrv_check_perm()
355 * call, the permission update is not performed and any preparations made
356 * for it (e.g. taken file locks) need to be undone.
358 * This function can be called even for nodes that never saw a
359 * bdrv_check_perm() call. It is a no-op then.
361 void (*bdrv_abort_perm_update
)(BlockDriverState
*bs
);
364 * Returns in @nperm and @nshared the permissions that the driver for @bs
365 * needs on its child @c, based on the cumulative permissions requested by
366 * the parents in @parent_perm and @parent_shared.
368 * If @c is NULL, return the permissions for attaching a new child for the
371 void (*bdrv_child_perm
)(BlockDriverState
*bs
, BdrvChild
*c
,
372 const BdrvChildRole
*role
,
373 uint64_t parent_perm
, uint64_t parent_shared
,
374 uint64_t *nperm
, uint64_t *nshared
);
376 QLIST_ENTRY(BlockDriver
) list
;
379 typedef struct BlockLimits
{
380 /* Alignment requirement, in bytes, for offset/length of I/O
381 * requests. Must be a power of 2 less than INT_MAX; defaults to
382 * 1 for drivers with modern byte interfaces, and to 512
384 uint32_t request_alignment
;
386 /* Maximum number of bytes that can be discarded at once (since it
387 * is signed, it must be < 2G, if set). Must be multiple of
388 * pdiscard_alignment, but need not be power of 2. May be 0 if no
389 * inherent 32-bit limit */
390 int32_t max_pdiscard
;
392 /* Optimal alignment for discard requests in bytes. A power of 2
393 * is best but not mandatory. Must be a multiple of
394 * bl.request_alignment, and must be less than max_pdiscard if
395 * that is set. May be 0 if bl.request_alignment is good enough */
396 uint32_t pdiscard_alignment
;
398 /* Maximum number of bytes that can zeroized at once (since it is
399 * signed, it must be < 2G, if set). Must be multiple of
400 * pwrite_zeroes_alignment. May be 0 if no inherent 32-bit limit */
401 int32_t max_pwrite_zeroes
;
403 /* Optimal alignment for write zeroes requests in bytes. A power
404 * of 2 is best but not mandatory. Must be a multiple of
405 * bl.request_alignment, and must be less than max_pwrite_zeroes
406 * if that is set. May be 0 if bl.request_alignment is good
408 uint32_t pwrite_zeroes_alignment
;
410 /* Optimal transfer length in bytes. A power of 2 is best but not
411 * mandatory. Must be a multiple of bl.request_alignment, or 0 if
412 * no preferred size */
413 uint32_t opt_transfer
;
415 /* Maximal transfer length in bytes. Need not be power of 2, but
416 * must be multiple of opt_transfer and bl.request_alignment, or 0
417 * for no 32-bit limit. For now, anything larger than INT_MAX is
419 uint32_t max_transfer
;
421 /* memory alignment, in bytes so that no bounce buffer is needed */
422 size_t min_mem_alignment
;
424 /* memory alignment, in bytes, for bounce buffer */
425 size_t opt_mem_alignment
;
427 /* maximum number of iovec elements */
431 typedef struct BdrvOpBlocker BdrvOpBlocker
;
433 typedef struct BdrvAioNotifier
{
434 void (*attached_aio_context
)(AioContext
*new_context
, void *opaque
);
435 void (*detach_aio_context
)(void *opaque
);
440 QLIST_ENTRY(BdrvAioNotifier
) list
;
443 struct BdrvChildRole
{
444 /* If true, bdrv_replace_in_backing_chain() doesn't change the node this
445 * BdrvChild points to. */
448 void (*inherit_options
)(int *child_flags
, QDict
*child_options
,
449 int parent_flags
, QDict
*parent_options
);
451 void (*change_media
)(BdrvChild
*child
, bool load
);
452 void (*resize
)(BdrvChild
*child
);
454 /* Returns a name that is supposedly more useful for human users than the
455 * node name for identifying the node in question (in particular, a BB
456 * name), or NULL if the parent can't provide a better name. */
457 const char* (*get_name
)(BdrvChild
*child
);
459 /* Returns a malloced string that describes the parent of the child for a
460 * human reader. This could be a node-name, BlockBackend name, qdev ID or
461 * QOM path of the device owning the BlockBackend, job type and ID etc. The
462 * caller is responsible for freeing the memory. */
463 char* (*get_parent_desc
)(BdrvChild
*child
);
466 * If this pair of functions is implemented, the parent doesn't issue new
467 * requests after returning from .drained_begin() until .drained_end() is
470 * Note that this can be nested. If drained_begin() was called twice, new
471 * I/O is allowed only after drained_end() was called twice, too.
473 void (*drained_begin
)(BdrvChild
*child
);
474 void (*drained_end
)(BdrvChild
*child
);
476 void (*attach
)(BdrvChild
*child
);
477 void (*detach
)(BdrvChild
*child
);
480 extern const BdrvChildRole child_file
;
481 extern const BdrvChildRole child_format
;
482 extern const BdrvChildRole child_backing
;
485 BlockDriverState
*bs
;
487 const BdrvChildRole
*role
;
491 * Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask)
496 * Permissions that can still be granted to other users of @bs while this
497 * BdrvChild is still attached to it. (BLK_PERM_* bitmask)
499 uint64_t shared_perm
;
501 QLIST_ENTRY(BdrvChild
) next
;
502 QLIST_ENTRY(BdrvChild
) next_parent
;
506 * Note: the function bdrv_append() copies and swaps contents of
507 * BlockDriverStates, so if you add new fields to this struct, please
508 * inspect bdrv_append() to determine if the new fields need to be
511 struct BlockDriverState
{
512 /* Protected by big QEMU lock or read-only after opening. No special
513 * locking needed during I/O...
515 int open_flags
; /* flags used to open the file, re-used for re-open */
516 bool read_only
; /* if true, the media is read only */
517 bool encrypted
; /* if true, the media is encrypted */
518 bool valid_key
; /* if true, a valid encryption key has been set */
519 bool sg
; /* if true, the device is a /dev/sg* */
520 bool probed
; /* if true, format was probed rather than specified */
522 BlockDriver
*drv
; /* NULL means no media */
525 AioContext
*aio_context
; /* event loop used for fd handlers, timers, etc */
526 /* long-running tasks intended to always use the same AioContext as this
527 * BDS may register themselves in this list to be notified of changes
528 * regarding this BDS's context */
529 QLIST_HEAD(, BdrvAioNotifier
) aio_notifiers
;
530 bool walking_aio_notifiers
; /* to make removal during iteration safe */
532 char filename
[PATH_MAX
];
533 char backing_file
[PATH_MAX
]; /* if non zero, the image is a diff of
535 char backing_format
[16]; /* if non-zero and backing_file exists */
537 QDict
*full_open_options
;
538 char exact_filename
[PATH_MAX
];
546 /* Flags honored during pwrite (so far: BDRV_REQ_FUA) */
547 unsigned int supported_write_flags
;
548 /* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA,
549 * BDRV_REQ_MAY_UNMAP) */
550 unsigned int supported_zero_flags
;
552 /* the following member gives a name to every node on the bs graph. */
554 /* element of the list of named nodes building the graph */
555 QTAILQ_ENTRY(BlockDriverState
) node_list
;
556 /* element of the list of all BlockDriverStates (all_bdrv_states) */
557 QTAILQ_ENTRY(BlockDriverState
) bs_list
;
558 /* element of the list of monitor-owned BDS */
559 QTAILQ_ENTRY(BlockDriverState
) monitor_list
;
562 /* operation blockers */
563 QLIST_HEAD(, BdrvOpBlocker
) op_blockers
[BLOCK_OP_TYPE_MAX
];
565 /* long-running background operation */
568 /* The node that this node inherited default options from (and a reopen on
569 * which can affect this node by changing these defaults). This is always a
570 * parent node of this node. */
571 BlockDriverState
*inherits_from
;
572 QLIST_HEAD(, BdrvChild
) children
;
573 QLIST_HEAD(, BdrvChild
) parents
;
576 QDict
*explicit_options
;
577 BlockdevDetectZeroesOptions detect_zeroes
;
579 /* The error object in use for blocking operations on backing_hd */
580 Error
*backing_blocker
;
582 /* Protected by AioContext lock */
584 /* If true, copy read backing sectors into image. Can be >1 if more
585 * than one client has requested copy-on-read.
589 /* If we are reading a disk image, give its size in sectors.
590 * Generally read-only; it is written to by load_vmstate and save_vmstate,
591 * but the block layer is quiescent during those.
593 int64_t total_sectors
;
595 /* Callback before write request is processed */
596 NotifierWithReturnList before_write_notifiers
;
598 /* number of in-flight requests; overall and serialising */
599 unsigned int in_flight
;
600 unsigned int serialising_in_flight
;
604 /* Offset after the highest byte written to */
605 uint64_t wr_highest_offset
;
607 /* threshold limit for writes, in bytes. "High water mark". */
608 uint64_t write_threshold_offset
;
609 NotifierWithReturn write_threshold_notifier
;
611 /* counter for nested bdrv_io_plug */
614 QLIST_HEAD(, BdrvTrackedRequest
) tracked_requests
;
615 CoQueue flush_queue
; /* Serializing flush queue */
616 bool active_flush_req
; /* Flush request in flight? */
617 unsigned int write_gen
; /* Current data generation */
618 unsigned int flushed_gen
; /* Flushed write generation */
620 QLIST_HEAD(, BdrvDirtyBitmap
) dirty_bitmaps
;
622 /* do we need to tell the quest if we have a volatile write cache? */
623 int enable_write_cache
;
628 struct BlockBackendRootState
{
631 BlockdevDetectZeroesOptions detect_zeroes
;
634 typedef enum BlockMirrorBackingMode
{
635 /* Reuse the existing backing chain from the source for the target.
636 * - sync=full: Set backing BDS to NULL.
637 * - sync=top: Use source's backing BDS.
638 * - sync=none: Use source as the backing BDS. */
639 MIRROR_SOURCE_BACKING_CHAIN
,
641 /* Open the target's backing chain completely anew */
642 MIRROR_OPEN_BACKING_CHAIN
,
644 /* Do not change the target's backing BDS after job completion */
645 MIRROR_LEAVE_BACKING_CHAIN
,
646 } BlockMirrorBackingMode
;
648 static inline BlockDriverState
*backing_bs(BlockDriverState
*bs
)
650 return bs
->backing
? bs
->backing
->bs
: NULL
;
654 /* Essential block drivers which must always be statically linked into qemu, and
655 * which therefore can be accessed without using bdrv_find_format() */
656 extern BlockDriver bdrv_file
;
657 extern BlockDriver bdrv_raw
;
658 extern BlockDriver bdrv_qcow2
;
660 int coroutine_fn
bdrv_co_preadv(BdrvChild
*child
,
661 int64_t offset
, unsigned int bytes
, QEMUIOVector
*qiov
,
662 BdrvRequestFlags flags
);
663 int coroutine_fn
bdrv_co_pwritev(BdrvChild
*child
,
664 int64_t offset
, unsigned int bytes
, QEMUIOVector
*qiov
,
665 BdrvRequestFlags flags
);
667 int get_tmp_filename(char *filename
, int size
);
668 BlockDriver
*bdrv_probe_all(const uint8_t *buf
, int buf_size
,
669 const char *filename
);
673 * bdrv_add_before_write_notifier:
675 * Register a callback that is invoked before write requests are processed but
676 * after any throttling or waiting for overlapping requests.
678 void bdrv_add_before_write_notifier(BlockDriverState
*bs
,
679 NotifierWithReturn
*notifier
);
682 * bdrv_detach_aio_context:
684 * May be called from .bdrv_detach_aio_context() to detach children from the
685 * current #AioContext. This is only needed by block drivers that manage their
686 * own children. Both ->file and ->backing are automatically handled and
687 * block drivers should not call this function on them explicitly.
689 void bdrv_detach_aio_context(BlockDriverState
*bs
);
692 * bdrv_attach_aio_context:
694 * May be called from .bdrv_attach_aio_context() to attach children to the new
695 * #AioContext. This is only needed by block drivers that manage their own
696 * children. Both ->file and ->backing are automatically handled and block
697 * drivers should not call this function on them explicitly.
699 void bdrv_attach_aio_context(BlockDriverState
*bs
,
700 AioContext
*new_context
);
703 * bdrv_add_aio_context_notifier:
705 * If a long-running job intends to be always run in the same AioContext as a
706 * certain BDS, it may use this function to be notified of changes regarding the
707 * association of the BDS to an AioContext.
709 * attached_aio_context() is called after the target BDS has been attached to a
710 * new AioContext; detach_aio_context() is called before the target BDS is being
711 * detached from its old AioContext.
713 void bdrv_add_aio_context_notifier(BlockDriverState
*bs
,
714 void (*attached_aio_context
)(AioContext
*new_context
, void *opaque
),
715 void (*detach_aio_context
)(void *opaque
), void *opaque
);
718 * bdrv_remove_aio_context_notifier:
720 * Unsubscribe of change notifications regarding the BDS's AioContext. The
721 * parameters given here have to be the same as those given to
722 * bdrv_add_aio_context_notifier().
724 void bdrv_remove_aio_context_notifier(BlockDriverState
*bs
,
725 void (*aio_context_attached
)(AioContext
*,
727 void (*aio_context_detached
)(void *),
732 * @bs: The BlockDriverState for which an I/O operation has been completed.
734 * Wake up the main thread if it is waiting on BDRV_POLL_WHILE. During
735 * synchronous I/O on a BlockDriverState that is attached to another
736 * I/O thread, the main thread lets the I/O thread's event loop run,
737 * waiting for the I/O operation to complete. A bdrv_wakeup will wake
738 * up the main thread if necessary.
740 * Manual calls to bdrv_wakeup are rarely necessary, because
741 * bdrv_dec_in_flight already calls it.
743 void bdrv_wakeup(BlockDriverState
*bs
);
746 int is_windows_drive(const char *filename
);
751 * @job_id: The id of the newly-created job, or %NULL to use the
752 * device name of @bs.
753 * @bs: Block device to operate on.
754 * @base: Block device that will become the new base, or %NULL to
755 * flatten the whole backing file chain onto @bs.
756 * @backing_file_str: The file name that will be written to @bs as the
757 * the new backing file if the job completes. Ignored if @base is %NULL.
758 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
759 * @on_error: The action to take upon error.
760 * @errp: Error object.
762 * Start a streaming operation on @bs. Clusters that are unallocated
763 * in @bs, but allocated in any image between @base and @bs (both
764 * exclusive) will be written to @bs. At the end of a successful
765 * streaming job, the backing file of @bs will be changed to
766 * @backing_file_str in the written image and to @base in the live
769 void stream_start(const char *job_id
, BlockDriverState
*bs
,
770 BlockDriverState
*base
, const char *backing_file_str
,
771 int64_t speed
, BlockdevOnError on_error
, Error
**errp
);
775 * @job_id: The id of the newly-created job, or %NULL to use the
776 * device name of @bs.
777 * @bs: Active block device.
778 * @top: Top block device to be committed.
779 * @base: Block device that will be written into, and become the new top.
780 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
781 * @on_error: The action to take upon error.
782 * @backing_file_str: String to use as the backing file in @top's overlay
783 * @filter_node_name: The node name that should be assigned to the filter
784 * driver that the commit job inserts into the graph above @top. NULL means
785 * that a node name should be autogenerated.
786 * @errp: Error object.
789 void commit_start(const char *job_id
, BlockDriverState
*bs
,
790 BlockDriverState
*base
, BlockDriverState
*top
, int64_t speed
,
791 BlockdevOnError on_error
, const char *backing_file_str
,
792 const char *filter_node_name
, Error
**errp
);
794 * commit_active_start:
795 * @job_id: The id of the newly-created job, or %NULL to use the
796 * device name of @bs.
797 * @bs: Active block device to be committed.
798 * @base: Block device that will be written into, and become the new top.
799 * @creation_flags: Flags that control the behavior of the Job lifetime.
800 * See @BlockJobCreateFlags
801 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
802 * @on_error: The action to take upon error.
803 * @filter_node_name: The node name that should be assigned to the filter
804 * driver that the commit job inserts into the graph above @bs. NULL means that
805 * a node name should be autogenerated.
806 * @cb: Completion function for the job.
807 * @opaque: Opaque pointer value passed to @cb.
808 * @errp: Error object.
809 * @auto_complete: Auto complete the job.
812 void commit_active_start(const char *job_id
, BlockDriverState
*bs
,
813 BlockDriverState
*base
, int creation_flags
,
814 int64_t speed
, BlockdevOnError on_error
,
815 const char *filter_node_name
,
816 BlockCompletionFunc
*cb
, void *opaque
, Error
**errp
,
820 * @job_id: The id of the newly-created job, or %NULL to use the
821 * device name of @bs.
822 * @bs: Block device to operate on.
823 * @target: Block device to write to.
824 * @replaces: Block graph node name to replace once the mirror is done. Can
825 * only be used when full mirroring is selected.
826 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
827 * @granularity: The chosen granularity for the dirty bitmap.
828 * @buf_size: The amount of data that can be in flight at one time.
829 * @mode: Whether to collapse all images in the chain to the target.
830 * @backing_mode: How to establish the target's backing chain after completion.
831 * @on_source_error: The action to take upon error reading from the source.
832 * @on_target_error: The action to take upon error writing to the target.
833 * @unmap: Whether to unmap target where source sectors only contain zeroes.
834 * @filter_node_name: The node name that should be assigned to the filter
835 * driver that the mirror job inserts into the graph above @bs. NULL means that
836 * a node name should be autogenerated.
837 * @errp: Error object.
839 * Start a mirroring operation on @bs. Clusters that are allocated
840 * in @bs will be written to @target until the job is cancelled or
841 * manually completed. At the end of a successful mirroring job,
842 * @bs will be switched to read from @target.
844 void mirror_start(const char *job_id
, BlockDriverState
*bs
,
845 BlockDriverState
*target
, const char *replaces
,
846 int64_t speed
, uint32_t granularity
, int64_t buf_size
,
847 MirrorSyncMode mode
, BlockMirrorBackingMode backing_mode
,
848 BlockdevOnError on_source_error
,
849 BlockdevOnError on_target_error
,
850 bool unmap
, const char *filter_node_name
, Error
**errp
);
854 * @job_id: The id of the newly-created job, or %NULL to use the
855 * device name of @bs.
856 * @bs: Block device to operate on.
857 * @target: Block device to write to.
858 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
859 * @sync_mode: What parts of the disk image should be copied to the destination.
860 * @sync_bitmap: The dirty bitmap if sync_mode is MIRROR_SYNC_MODE_INCREMENTAL.
861 * @on_source_error: The action to take upon error reading from the source.
862 * @on_target_error: The action to take upon error writing to the target.
863 * @creation_flags: Flags that control the behavior of the Job lifetime.
864 * See @BlockJobCreateFlags
865 * @cb: Completion function for the job.
866 * @opaque: Opaque pointer value passed to @cb.
867 * @txn: Transaction that this job is part of (may be NULL).
869 * Create a backup operation on @bs. Clusters in @bs are written to @target
870 * until the job is cancelled or manually completed.
872 BlockJob
*backup_job_create(const char *job_id
, BlockDriverState
*bs
,
873 BlockDriverState
*target
, int64_t speed
,
874 MirrorSyncMode sync_mode
,
875 BdrvDirtyBitmap
*sync_bitmap
,
877 BlockdevOnError on_source_error
,
878 BlockdevOnError on_target_error
,
880 BlockCompletionFunc
*cb
, void *opaque
,
881 BlockJobTxn
*txn
, Error
**errp
);
883 void hmp_drive_add_node(Monitor
*mon
, const char *optstr
);
885 BdrvChild
*bdrv_root_attach_child(BlockDriverState
*child_bs
,
886 const char *child_name
,
887 const BdrvChildRole
*child_role
,
888 uint64_t perm
, uint64_t shared_perm
,
889 void *opaque
, Error
**errp
);
890 void bdrv_root_unref_child(BdrvChild
*child
);
892 int bdrv_child_check_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
,
894 void bdrv_child_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
);
895 void bdrv_child_abort_perm_update(BdrvChild
*c
);
896 int bdrv_child_try_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
,
899 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by
900 * block filters: Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED and RESIZE to
902 void bdrv_filter_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
903 const BdrvChildRole
*role
,
904 uint64_t perm
, uint64_t shared
,
905 uint64_t *nperm
, uint64_t *nshared
);
907 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by
908 * (non-raw) image formats: Like above for bs->backing, but for bs->file it
909 * requires WRITE | RESIZE for read-write images, always requires
910 * CONSISTENT_READ and doesn't share WRITE. */
911 void bdrv_format_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
912 const BdrvChildRole
*role
,
913 uint64_t perm
, uint64_t shared
,
914 uint64_t *nperm
, uint64_t *nshared
);
916 const char *bdrv_get_parent_name(const BlockDriverState
*bs
);
917 void blk_dev_change_media_cb(BlockBackend
*blk
, bool load
, Error
**errp
);
918 bool blk_dev_has_removable_media(BlockBackend
*blk
);
919 bool blk_dev_has_tray(BlockBackend
*blk
);
920 void blk_dev_eject_request(BlockBackend
*blk
, bool force
);
921 bool blk_dev_is_tray_open(BlockBackend
*blk
);
922 bool blk_dev_is_medium_locked(BlockBackend
*blk
);
924 void bdrv_set_dirty(BlockDriverState
*bs
, int64_t cur_sector
, int64_t nr_sect
);
925 bool bdrv_requests_pending(BlockDriverState
*bs
);
927 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap
*bitmap
, HBitmap
**out
);
928 void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap
*bitmap
, HBitmap
*in
);
930 void bdrv_inc_in_flight(BlockDriverState
*bs
);
931 void bdrv_dec_in_flight(BlockDriverState
*bs
);
933 void blockdev_close_all_bdrv_states(void);
935 #endif /* BLOCK_INT_H */