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/stats64.h"
33 #include "qemu/timer.h"
34 #include "qapi-types.h"
35 #include "qemu/hbitmap.h"
36 #include "block/snapshot.h"
37 #include "qemu/main-loop.h"
38 #include "qemu/throttle.h"
40 #define BLOCK_FLAG_LAZY_REFCOUNTS 8
42 #define BLOCK_OPT_SIZE "size"
43 #define BLOCK_OPT_ENCRYPT "encryption"
44 #define BLOCK_OPT_ENCRYPT_FORMAT "encrypt.format"
45 #define BLOCK_OPT_COMPAT6 "compat6"
46 #define BLOCK_OPT_HWVERSION "hwversion"
47 #define BLOCK_OPT_BACKING_FILE "backing_file"
48 #define BLOCK_OPT_BACKING_FMT "backing_fmt"
49 #define BLOCK_OPT_CLUSTER_SIZE "cluster_size"
50 #define BLOCK_OPT_TABLE_SIZE "table_size"
51 #define BLOCK_OPT_PREALLOC "preallocation"
52 #define BLOCK_OPT_SUBFMT "subformat"
53 #define BLOCK_OPT_COMPAT_LEVEL "compat"
54 #define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts"
55 #define BLOCK_OPT_ADAPTER_TYPE "adapter_type"
56 #define BLOCK_OPT_REDUNDANCY "redundancy"
57 #define BLOCK_OPT_NOCOW "nocow"
58 #define BLOCK_OPT_OBJECT_SIZE "object_size"
59 #define BLOCK_OPT_REFCOUNT_BITS "refcount_bits"
61 #define BLOCK_PROBE_BUF_SIZE 512
63 enum BdrvTrackedRequestType
{
69 typedef struct BdrvTrackedRequest
{
73 enum BdrvTrackedRequestType type
;
76 int64_t overlap_offset
;
77 unsigned int overlap_bytes
;
79 QLIST_ENTRY(BdrvTrackedRequest
) list
;
80 Coroutine
*co
; /* owner, used for deadlock detection */
81 CoQueue wait_queue
; /* coroutines blocked on this request */
83 struct BdrvTrackedRequest
*waiting_for
;
87 const char *format_name
;
90 /* set to true if the BlockDriver is a block filter */
92 /* for snapshots block filter like Quorum can implement the
93 * following recursive callback.
94 * It's purpose is to recurse on the filter children while calling
95 * bdrv_recurse_is_first_non_filter on them.
96 * For a sample implementation look in the future Quorum block filter.
98 bool (*bdrv_recurse_is_first_non_filter
)(BlockDriverState
*bs
,
99 BlockDriverState
*candidate
);
101 int (*bdrv_probe
)(const uint8_t *buf
, int buf_size
, const char *filename
);
102 int (*bdrv_probe_device
)(const char *filename
);
104 /* Any driver implementing this callback is expected to be able to handle
105 * NULL file names in its .bdrv_open() implementation */
106 void (*bdrv_parse_filename
)(const char *filename
, QDict
*options
, Error
**errp
);
107 /* Drivers not implementing bdrv_parse_filename nor bdrv_open should have
108 * this field set to true, except ones that are defined only by their
110 * An example of the last type will be the quorum block driver.
112 bool bdrv_needs_filename
;
114 /* Set if a driver can support backing files */
115 bool supports_backing
;
117 /* For handling image reopen for split or non-split files */
118 int (*bdrv_reopen_prepare
)(BDRVReopenState
*reopen_state
,
119 BlockReopenQueue
*queue
, Error
**errp
);
120 void (*bdrv_reopen_commit
)(BDRVReopenState
*reopen_state
);
121 void (*bdrv_reopen_abort
)(BDRVReopenState
*reopen_state
);
122 void (*bdrv_join_options
)(QDict
*options
, QDict
*old_options
);
124 int (*bdrv_open
)(BlockDriverState
*bs
, QDict
*options
, int flags
,
126 int (*bdrv_file_open
)(BlockDriverState
*bs
, QDict
*options
, int flags
,
128 void (*bdrv_close
)(BlockDriverState
*bs
);
129 int (*bdrv_create
)(const char *filename
, QemuOpts
*opts
, Error
**errp
);
130 int (*bdrv_set_key
)(BlockDriverState
*bs
, const char *key
);
131 int (*bdrv_make_empty
)(BlockDriverState
*bs
);
133 void (*bdrv_refresh_filename
)(BlockDriverState
*bs
, QDict
*options
);
136 BlockAIOCB
*(*bdrv_aio_readv
)(BlockDriverState
*bs
,
137 int64_t sector_num
, QEMUIOVector
*qiov
, int nb_sectors
,
138 BlockCompletionFunc
*cb
, void *opaque
);
139 BlockAIOCB
*(*bdrv_aio_writev
)(BlockDriverState
*bs
,
140 int64_t sector_num
, QEMUIOVector
*qiov
, int nb_sectors
,
141 BlockCompletionFunc
*cb
, void *opaque
);
142 BlockAIOCB
*(*bdrv_aio_flush
)(BlockDriverState
*bs
,
143 BlockCompletionFunc
*cb
, void *opaque
);
144 BlockAIOCB
*(*bdrv_aio_pdiscard
)(BlockDriverState
*bs
,
145 int64_t offset
, int bytes
,
146 BlockCompletionFunc
*cb
, void *opaque
);
148 int coroutine_fn (*bdrv_co_readv
)(BlockDriverState
*bs
,
149 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
);
150 int coroutine_fn (*bdrv_co_preadv
)(BlockDriverState
*bs
,
151 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
, int flags
);
152 int coroutine_fn (*bdrv_co_writev
)(BlockDriverState
*bs
,
153 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
);
154 int coroutine_fn (*bdrv_co_writev_flags
)(BlockDriverState
*bs
,
155 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
, int flags
);
156 int coroutine_fn (*bdrv_co_pwritev
)(BlockDriverState
*bs
,
157 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
, int flags
);
160 * Efficiently zero a region of the disk image. Typically an image format
161 * would use a compact metadata representation to implement this. This
162 * function pointer may be NULL or return -ENOSUP and .bdrv_co_writev()
163 * will be called instead.
165 int coroutine_fn (*bdrv_co_pwrite_zeroes
)(BlockDriverState
*bs
,
166 int64_t offset
, int bytes
, BdrvRequestFlags flags
);
167 int coroutine_fn (*bdrv_co_pdiscard
)(BlockDriverState
*bs
,
168 int64_t offset
, int bytes
);
171 * Building block for bdrv_block_status[_above]. The driver should
172 * answer only according to the current layer, and should not
173 * set BDRV_BLOCK_ALLOCATED, but may set BDRV_BLOCK_RAW. See block.h
174 * for the meaning of _DATA, _ZERO, and _OFFSET_VALID.
176 int64_t coroutine_fn (*bdrv_co_get_block_status
)(BlockDriverState
*bs
,
177 int64_t sector_num
, int nb_sectors
, int *pnum
,
178 BlockDriverState
**file
);
181 * Invalidate any cached meta-data.
183 void (*bdrv_invalidate_cache
)(BlockDriverState
*bs
, Error
**errp
);
184 int (*bdrv_inactivate
)(BlockDriverState
*bs
);
187 * Flushes all data for all layers by calling bdrv_co_flush for underlying
188 * layers, if needed. This function is needed for deterministic
189 * synchronization of the flush finishing callback.
191 int coroutine_fn (*bdrv_co_flush
)(BlockDriverState
*bs
);
194 * Flushes all data that was already written to the OS all the way down to
195 * the disk (for example file-posix.c calls fsync()).
197 int coroutine_fn (*bdrv_co_flush_to_disk
)(BlockDriverState
*bs
);
200 * Flushes all internal caches to the OS. The data may still sit in a
201 * writeback cache of the host OS, but it will survive a crash of the qemu
204 int coroutine_fn (*bdrv_co_flush_to_os
)(BlockDriverState
*bs
);
206 const char *protocol_name
;
207 int (*bdrv_truncate
)(BlockDriverState
*bs
, int64_t offset
,
208 PreallocMode prealloc
, Error
**errp
);
210 int64_t (*bdrv_getlength
)(BlockDriverState
*bs
);
211 bool has_variable_length
;
212 int64_t (*bdrv_get_allocated_file_size
)(BlockDriverState
*bs
);
213 BlockMeasureInfo
*(*bdrv_measure
)(QemuOpts
*opts
, BlockDriverState
*in_bs
,
216 int coroutine_fn (*bdrv_co_pwritev_compressed
)(BlockDriverState
*bs
,
217 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
);
219 int (*bdrv_snapshot_create
)(BlockDriverState
*bs
,
220 QEMUSnapshotInfo
*sn_info
);
221 int (*bdrv_snapshot_goto
)(BlockDriverState
*bs
,
222 const char *snapshot_id
);
223 int (*bdrv_snapshot_delete
)(BlockDriverState
*bs
,
224 const char *snapshot_id
,
227 int (*bdrv_snapshot_list
)(BlockDriverState
*bs
,
228 QEMUSnapshotInfo
**psn_info
);
229 int (*bdrv_snapshot_load_tmp
)(BlockDriverState
*bs
,
230 const char *snapshot_id
,
233 int (*bdrv_get_info
)(BlockDriverState
*bs
, BlockDriverInfo
*bdi
);
234 ImageInfoSpecific
*(*bdrv_get_specific_info
)(BlockDriverState
*bs
);
236 int coroutine_fn (*bdrv_save_vmstate
)(BlockDriverState
*bs
,
239 int coroutine_fn (*bdrv_load_vmstate
)(BlockDriverState
*bs
,
243 int (*bdrv_change_backing_file
)(BlockDriverState
*bs
,
244 const char *backing_file
, const char *backing_fmt
);
246 /* removable device specific */
247 bool (*bdrv_is_inserted
)(BlockDriverState
*bs
);
248 int (*bdrv_media_changed
)(BlockDriverState
*bs
);
249 void (*bdrv_eject
)(BlockDriverState
*bs
, bool eject_flag
);
250 void (*bdrv_lock_medium
)(BlockDriverState
*bs
, bool locked
);
252 /* to control generic scsi devices */
253 BlockAIOCB
*(*bdrv_aio_ioctl
)(BlockDriverState
*bs
,
254 unsigned long int req
, void *buf
,
255 BlockCompletionFunc
*cb
, void *opaque
);
256 int coroutine_fn (*bdrv_co_ioctl
)(BlockDriverState
*bs
,
257 unsigned long int req
, void *buf
);
259 /* List of options for creating images, terminated by name == NULL */
260 QemuOptsList
*create_opts
;
263 * Returns 0 for completed check, -errno for internal errors.
264 * The check results are stored in result.
266 int (*bdrv_check
)(BlockDriverState
*bs
, BdrvCheckResult
*result
,
269 int (*bdrv_amend_options
)(BlockDriverState
*bs
, QemuOpts
*opts
,
270 BlockDriverAmendStatusCB
*status_cb
,
273 void (*bdrv_debug_event
)(BlockDriverState
*bs
, BlkdebugEvent event
);
275 /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */
276 int (*bdrv_debug_breakpoint
)(BlockDriverState
*bs
, const char *event
,
278 int (*bdrv_debug_remove_breakpoint
)(BlockDriverState
*bs
,
280 int (*bdrv_debug_resume
)(BlockDriverState
*bs
, const char *tag
);
281 bool (*bdrv_debug_is_suspended
)(BlockDriverState
*bs
, const char *tag
);
283 void (*bdrv_refresh_limits
)(BlockDriverState
*bs
, Error
**errp
);
286 * Returns 1 if newly created images are guaranteed to contain only
287 * zeros, 0 otherwise.
289 int (*bdrv_has_zero_init
)(BlockDriverState
*bs
);
291 /* Remove fd handlers, timers, and other event loop callbacks so the event
292 * loop is no longer in use. Called with no in-flight requests and in
293 * depth-first traversal order with parents before child nodes.
295 void (*bdrv_detach_aio_context
)(BlockDriverState
*bs
);
297 /* Add fd handlers, timers, and other event loop callbacks so I/O requests
298 * can be processed again. Called with no in-flight requests and in
299 * depth-first traversal order with child nodes before parent nodes.
301 void (*bdrv_attach_aio_context
)(BlockDriverState
*bs
,
302 AioContext
*new_context
);
304 /* io queue for linux-aio */
305 void (*bdrv_io_plug
)(BlockDriverState
*bs
);
306 void (*bdrv_io_unplug
)(BlockDriverState
*bs
);
309 * Try to get @bs's logical and physical block size.
310 * On success, store them in @bsz and return zero.
311 * On failure, return negative errno.
313 int (*bdrv_probe_blocksizes
)(BlockDriverState
*bs
, BlockSizes
*bsz
);
315 * Try to get @bs's geometry (cyls, heads, sectors)
316 * On success, store them in @geo and return 0.
317 * On failure return -errno.
318 * Only drivers that want to override guest geometry implement this
319 * callback; see hd_geometry_guess().
321 int (*bdrv_probe_geometry
)(BlockDriverState
*bs
, HDGeometry
*geo
);
324 * Drain and stop any internal sources of requests in the driver, and
325 * remain so until next I/O callback (e.g. bdrv_co_writev) is called.
327 void coroutine_fn (*bdrv_co_drain
)(BlockDriverState
*bs
);
329 void (*bdrv_add_child
)(BlockDriverState
*parent
, BlockDriverState
*child
,
331 void (*bdrv_del_child
)(BlockDriverState
*parent
, BdrvChild
*child
,
335 * Informs the block driver that a permission change is intended. The
336 * driver checks whether the change is permissible and may take other
337 * preparations for the change (e.g. get file system locks). This operation
338 * is always followed either by a call to either .bdrv_set_perm or
339 * .bdrv_abort_perm_update.
341 * Checks whether the requested set of cumulative permissions in @perm
342 * can be granted for accessing @bs and whether no other users are using
343 * permissions other than those given in @shared (both arguments take
344 * BLK_PERM_* bitmasks).
346 * If both conditions are met, 0 is returned. Otherwise, -errno is returned
347 * and errp is set to an error describing the conflict.
349 int (*bdrv_check_perm
)(BlockDriverState
*bs
, uint64_t perm
,
350 uint64_t shared
, Error
**errp
);
353 * Called to inform the driver that the set of cumulative set of used
354 * permissions for @bs has changed to @perm, and the set of sharable
355 * permission to @shared. The driver can use this to propagate changes to
356 * its children (i.e. request permissions only if a parent actually needs
359 * This function is only invoked after bdrv_check_perm(), so block drivers
360 * may rely on preparations made in their .bdrv_check_perm implementation.
362 void (*bdrv_set_perm
)(BlockDriverState
*bs
, uint64_t perm
, uint64_t shared
);
365 * Called to inform the driver that after a previous bdrv_check_perm()
366 * call, the permission update is not performed and any preparations made
367 * for it (e.g. taken file locks) need to be undone.
369 * This function can be called even for nodes that never saw a
370 * bdrv_check_perm() call. It is a no-op then.
372 void (*bdrv_abort_perm_update
)(BlockDriverState
*bs
);
375 * Returns in @nperm and @nshared the permissions that the driver for @bs
376 * needs on its child @c, based on the cumulative permissions requested by
377 * the parents in @parent_perm and @parent_shared.
379 * If @c is NULL, return the permissions for attaching a new child for the
382 void (*bdrv_child_perm
)(BlockDriverState
*bs
, BdrvChild
*c
,
383 const BdrvChildRole
*role
,
384 uint64_t parent_perm
, uint64_t parent_shared
,
385 uint64_t *nperm
, uint64_t *nshared
);
388 * Bitmaps should be marked as 'IN_USE' in the image on reopening image
389 * as rw. This handler should realize it. It also should unset readonly
390 * field of BlockDirtyBitmap's in case of success.
392 int (*bdrv_reopen_bitmaps_rw
)(BlockDriverState
*bs
, Error
**errp
);
393 bool (*bdrv_can_store_new_dirty_bitmap
)(BlockDriverState
*bs
,
395 uint32_t granularity
,
397 void (*bdrv_remove_persistent_dirty_bitmap
)(BlockDriverState
*bs
,
401 QLIST_ENTRY(BlockDriver
) list
;
404 typedef struct BlockLimits
{
405 /* Alignment requirement, in bytes, for offset/length of I/O
406 * requests. Must be a power of 2 less than INT_MAX; defaults to
407 * 1 for drivers with modern byte interfaces, and to 512
409 uint32_t request_alignment
;
411 /* Maximum number of bytes that can be discarded at once (since it
412 * is signed, it must be < 2G, if set). Must be multiple of
413 * pdiscard_alignment, but need not be power of 2. May be 0 if no
414 * inherent 32-bit limit */
415 int32_t max_pdiscard
;
417 /* Optimal alignment for discard requests in bytes. A power of 2
418 * is best but not mandatory. Must be a multiple of
419 * bl.request_alignment, and must be less than max_pdiscard if
420 * that is set. May be 0 if bl.request_alignment is good enough */
421 uint32_t pdiscard_alignment
;
423 /* Maximum number of bytes that can zeroized at once (since it is
424 * signed, it must be < 2G, if set). Must be multiple of
425 * pwrite_zeroes_alignment. May be 0 if no inherent 32-bit limit */
426 int32_t max_pwrite_zeroes
;
428 /* Optimal alignment for write zeroes requests in bytes. A power
429 * of 2 is best but not mandatory. Must be a multiple of
430 * bl.request_alignment, and must be less than max_pwrite_zeroes
431 * if that is set. May be 0 if bl.request_alignment is good
433 uint32_t pwrite_zeroes_alignment
;
435 /* Optimal transfer length in bytes. A power of 2 is best but not
436 * mandatory. Must be a multiple of bl.request_alignment, or 0 if
437 * no preferred size */
438 uint32_t opt_transfer
;
440 /* Maximal transfer length in bytes. Need not be power of 2, but
441 * must be multiple of opt_transfer and bl.request_alignment, or 0
442 * for no 32-bit limit. For now, anything larger than INT_MAX is
444 uint32_t max_transfer
;
446 /* memory alignment, in bytes so that no bounce buffer is needed */
447 size_t min_mem_alignment
;
449 /* memory alignment, in bytes, for bounce buffer */
450 size_t opt_mem_alignment
;
452 /* maximum number of iovec elements */
456 typedef struct BdrvOpBlocker BdrvOpBlocker
;
458 typedef struct BdrvAioNotifier
{
459 void (*attached_aio_context
)(AioContext
*new_context
, void *opaque
);
460 void (*detach_aio_context
)(void *opaque
);
465 QLIST_ENTRY(BdrvAioNotifier
) list
;
468 struct BdrvChildRole
{
469 /* If true, bdrv_replace_node() doesn't change the node this BdrvChild
473 void (*inherit_options
)(int *child_flags
, QDict
*child_options
,
474 int parent_flags
, QDict
*parent_options
);
476 void (*change_media
)(BdrvChild
*child
, bool load
);
477 void (*resize
)(BdrvChild
*child
);
479 /* Returns a name that is supposedly more useful for human users than the
480 * node name for identifying the node in question (in particular, a BB
481 * name), or NULL if the parent can't provide a better name. */
482 const char *(*get_name
)(BdrvChild
*child
);
484 /* Returns a malloced string that describes the parent of the child for a
485 * human reader. This could be a node-name, BlockBackend name, qdev ID or
486 * QOM path of the device owning the BlockBackend, job type and ID etc. The
487 * caller is responsible for freeing the memory. */
488 char *(*get_parent_desc
)(BdrvChild
*child
);
491 * If this pair of functions is implemented, the parent doesn't issue new
492 * requests after returning from .drained_begin() until .drained_end() is
495 * Note that this can be nested. If drained_begin() was called twice, new
496 * I/O is allowed only after drained_end() was called twice, too.
498 void (*drained_begin
)(BdrvChild
*child
);
499 void (*drained_end
)(BdrvChild
*child
);
501 /* Notifies the parent that the child has been activated/inactivated (e.g.
502 * when migration is completing) and it can start/stop requesting
503 * permissions and doing I/O on it. */
504 void (*activate
)(BdrvChild
*child
, Error
**errp
);
505 int (*inactivate
)(BdrvChild
*child
);
507 void (*attach
)(BdrvChild
*child
);
508 void (*detach
)(BdrvChild
*child
);
511 extern const BdrvChildRole child_file
;
512 extern const BdrvChildRole child_format
;
513 extern const BdrvChildRole child_backing
;
516 BlockDriverState
*bs
;
518 const BdrvChildRole
*role
;
522 * Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask)
527 * Permissions that can still be granted to other users of @bs while this
528 * BdrvChild is still attached to it. (BLK_PERM_* bitmask)
530 uint64_t shared_perm
;
532 QLIST_ENTRY(BdrvChild
) next
;
533 QLIST_ENTRY(BdrvChild
) next_parent
;
537 * Note: the function bdrv_append() copies and swaps contents of
538 * BlockDriverStates, so if you add new fields to this struct, please
539 * inspect bdrv_append() to determine if the new fields need to be
542 struct BlockDriverState
{
543 /* Protected by big QEMU lock or read-only after opening. No special
544 * locking needed during I/O...
546 int open_flags
; /* flags used to open the file, re-used for re-open */
547 bool read_only
; /* if true, the media is read only */
548 bool encrypted
; /* if true, the media is encrypted */
549 bool sg
; /* if true, the device is a /dev/sg* */
550 bool probed
; /* if true, format was probed rather than specified */
551 bool force_share
; /* if true, always allow all shared permissions */
553 BlockDriver
*drv
; /* NULL means no media */
556 AioContext
*aio_context
; /* event loop used for fd handlers, timers, etc */
557 /* long-running tasks intended to always use the same AioContext as this
558 * BDS may register themselves in this list to be notified of changes
559 * regarding this BDS's context */
560 QLIST_HEAD(, BdrvAioNotifier
) aio_notifiers
;
561 bool walking_aio_notifiers
; /* to make removal during iteration safe */
563 char filename
[PATH_MAX
];
564 char backing_file
[PATH_MAX
]; /* if non zero, the image is a diff of
566 char backing_format
[16]; /* if non-zero and backing_file exists */
568 QDict
*full_open_options
;
569 char exact_filename
[PATH_MAX
];
577 /* Flags honored during pwrite (so far: BDRV_REQ_FUA) */
578 unsigned int supported_write_flags
;
579 /* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA,
580 * BDRV_REQ_MAY_UNMAP) */
581 unsigned int supported_zero_flags
;
583 /* the following member gives a name to every node on the bs graph. */
585 /* element of the list of named nodes building the graph */
586 QTAILQ_ENTRY(BlockDriverState
) node_list
;
587 /* element of the list of all BlockDriverStates (all_bdrv_states) */
588 QTAILQ_ENTRY(BlockDriverState
) bs_list
;
589 /* element of the list of monitor-owned BDS */
590 QTAILQ_ENTRY(BlockDriverState
) monitor_list
;
593 /* operation blockers */
594 QLIST_HEAD(, BdrvOpBlocker
) op_blockers
[BLOCK_OP_TYPE_MAX
];
596 /* long-running background operation */
599 /* The node that this node inherited default options from (and a reopen on
600 * which can affect this node by changing these defaults). This is always a
601 * parent node of this node. */
602 BlockDriverState
*inherits_from
;
603 QLIST_HEAD(, BdrvChild
) children
;
604 QLIST_HEAD(, BdrvChild
) parents
;
607 QDict
*explicit_options
;
608 BlockdevDetectZeroesOptions detect_zeroes
;
610 /* The error object in use for blocking operations on backing_hd */
611 Error
*backing_blocker
;
613 /* Protected by AioContext lock */
615 /* If we are reading a disk image, give its size in sectors.
616 * Generally read-only; it is written to by load_snapshot and
617 * save_snaphost, but the block layer is quiescent during those.
619 int64_t total_sectors
;
621 /* Callback before write request is processed */
622 NotifierWithReturnList before_write_notifiers
;
624 /* threshold limit for writes, in bytes. "High water mark". */
625 uint64_t write_threshold_offset
;
626 NotifierWithReturn write_threshold_notifier
;
628 /* Writing to the list requires the BQL _and_ the dirty_bitmap_mutex.
629 * Reading from the list can be done with either the BQL or the
630 * dirty_bitmap_mutex. Modifying a bitmap only requires
631 * dirty_bitmap_mutex. */
632 QemuMutex dirty_bitmap_mutex
;
633 QLIST_HEAD(, BdrvDirtyBitmap
) dirty_bitmaps
;
635 /* Offset after the highest byte written to */
636 Stat64 wr_highest_offset
;
638 /* If true, copy read backing sectors into image. Can be >1 if more
639 * than one client has requested copy-on-read. Accessed with atomic
644 /* number of in-flight requests; overall and serialising.
645 * Accessed with atomic ops.
647 unsigned int in_flight
;
648 unsigned int serialising_in_flight
;
650 /* Internal to BDRV_POLL_WHILE and bdrv_wakeup. Accessed with atomic
655 /* counter for nested bdrv_io_plug.
656 * Accessed with atomic ops.
660 /* do we need to tell the quest if we have a volatile write cache? */
661 int enable_write_cache
;
663 /* Accessed with atomic ops. */
665 unsigned int write_gen
; /* Current data generation */
667 /* Protected by reqs_lock. */
669 QLIST_HEAD(, BdrvTrackedRequest
) tracked_requests
;
670 CoQueue flush_queue
; /* Serializing flush queue */
671 bool active_flush_req
; /* Flush request in flight? */
673 /* Only read/written by whoever has set active_flush_req to true. */
674 unsigned int flushed_gen
; /* Flushed write generation */
677 struct BlockBackendRootState
{
680 BlockdevDetectZeroesOptions detect_zeroes
;
683 typedef enum BlockMirrorBackingMode
{
684 /* Reuse the existing backing chain from the source for the target.
685 * - sync=full: Set backing BDS to NULL.
686 * - sync=top: Use source's backing BDS.
687 * - sync=none: Use source as the backing BDS. */
688 MIRROR_SOURCE_BACKING_CHAIN
,
690 /* Open the target's backing chain completely anew */
691 MIRROR_OPEN_BACKING_CHAIN
,
693 /* Do not change the target's backing BDS after job completion */
694 MIRROR_LEAVE_BACKING_CHAIN
,
695 } BlockMirrorBackingMode
;
697 static inline BlockDriverState
*backing_bs(BlockDriverState
*bs
)
699 return bs
->backing
? bs
->backing
->bs
: NULL
;
703 /* Essential block drivers which must always be statically linked into qemu, and
704 * which therefore can be accessed without using bdrv_find_format() */
705 extern BlockDriver bdrv_file
;
706 extern BlockDriver bdrv_raw
;
707 extern BlockDriver bdrv_qcow2
;
709 int coroutine_fn
bdrv_co_preadv(BdrvChild
*child
,
710 int64_t offset
, unsigned int bytes
, QEMUIOVector
*qiov
,
711 BdrvRequestFlags flags
);
712 int coroutine_fn
bdrv_co_pwritev(BdrvChild
*child
,
713 int64_t offset
, unsigned int bytes
, QEMUIOVector
*qiov
,
714 BdrvRequestFlags flags
);
716 int get_tmp_filename(char *filename
, int size
);
717 BlockDriver
*bdrv_probe_all(const uint8_t *buf
, int buf_size
,
718 const char *filename
);
720 void bdrv_parse_filename_strip_prefix(const char *filename
, const char *prefix
,
725 * bdrv_add_before_write_notifier:
727 * Register a callback that is invoked before write requests are processed but
728 * after any throttling or waiting for overlapping requests.
730 void bdrv_add_before_write_notifier(BlockDriverState
*bs
,
731 NotifierWithReturn
*notifier
);
734 * bdrv_detach_aio_context:
736 * May be called from .bdrv_detach_aio_context() to detach children from the
737 * current #AioContext. This is only needed by block drivers that manage their
738 * own children. Both ->file and ->backing are automatically handled and
739 * block drivers should not call this function on them explicitly.
741 void bdrv_detach_aio_context(BlockDriverState
*bs
);
744 * bdrv_attach_aio_context:
746 * May be called from .bdrv_attach_aio_context() to attach children to the new
747 * #AioContext. This is only needed by block drivers that manage their own
748 * children. Both ->file and ->backing are automatically handled and block
749 * drivers should not call this function on them explicitly.
751 void bdrv_attach_aio_context(BlockDriverState
*bs
,
752 AioContext
*new_context
);
755 * bdrv_add_aio_context_notifier:
757 * If a long-running job intends to be always run in the same AioContext as a
758 * certain BDS, it may use this function to be notified of changes regarding the
759 * association of the BDS to an AioContext.
761 * attached_aio_context() is called after the target BDS has been attached to a
762 * new AioContext; detach_aio_context() is called before the target BDS is being
763 * detached from its old AioContext.
765 void bdrv_add_aio_context_notifier(BlockDriverState
*bs
,
766 void (*attached_aio_context
)(AioContext
*new_context
, void *opaque
),
767 void (*detach_aio_context
)(void *opaque
), void *opaque
);
770 * bdrv_remove_aio_context_notifier:
772 * Unsubscribe of change notifications regarding the BDS's AioContext. The
773 * parameters given here have to be the same as those given to
774 * bdrv_add_aio_context_notifier().
776 void bdrv_remove_aio_context_notifier(BlockDriverState
*bs
,
777 void (*aio_context_attached
)(AioContext
*,
779 void (*aio_context_detached
)(void *),
784 * @bs: The BlockDriverState for which an I/O operation has been completed.
786 * Wake up the main thread if it is waiting on BDRV_POLL_WHILE. During
787 * synchronous I/O on a BlockDriverState that is attached to another
788 * I/O thread, the main thread lets the I/O thread's event loop run,
789 * waiting for the I/O operation to complete. A bdrv_wakeup will wake
790 * up the main thread if necessary.
792 * Manual calls to bdrv_wakeup are rarely necessary, because
793 * bdrv_dec_in_flight already calls it.
795 void bdrv_wakeup(BlockDriverState
*bs
);
798 int is_windows_drive(const char *filename
);
803 * @job_id: The id of the newly-created job, or %NULL to use the
804 * device name of @bs.
805 * @bs: Block device to operate on.
806 * @base: Block device that will become the new base, or %NULL to
807 * flatten the whole backing file chain onto @bs.
808 * @backing_file_str: The file name that will be written to @bs as the
809 * the new backing file if the job completes. Ignored if @base is %NULL.
810 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
811 * @on_error: The action to take upon error.
812 * @errp: Error object.
814 * Start a streaming operation on @bs. Clusters that are unallocated
815 * in @bs, but allocated in any image between @base and @bs (both
816 * exclusive) will be written to @bs. At the end of a successful
817 * streaming job, the backing file of @bs will be changed to
818 * @backing_file_str in the written image and to @base in the live
821 void stream_start(const char *job_id
, BlockDriverState
*bs
,
822 BlockDriverState
*base
, const char *backing_file_str
,
823 int64_t speed
, BlockdevOnError on_error
, Error
**errp
);
827 * @job_id: The id of the newly-created job, or %NULL to use the
828 * device name of @bs.
829 * @bs: Active block device.
830 * @top: Top block device to be committed.
831 * @base: Block device that will be written into, and become the new top.
832 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
833 * @on_error: The action to take upon error.
834 * @backing_file_str: String to use as the backing file in @top's overlay
835 * @filter_node_name: The node name that should be assigned to the filter
836 * driver that the commit job inserts into the graph above @top. NULL means
837 * that a node name should be autogenerated.
838 * @errp: Error object.
841 void commit_start(const char *job_id
, BlockDriverState
*bs
,
842 BlockDriverState
*base
, BlockDriverState
*top
, int64_t speed
,
843 BlockdevOnError on_error
, const char *backing_file_str
,
844 const char *filter_node_name
, Error
**errp
);
846 * commit_active_start:
847 * @job_id: The id of the newly-created job, or %NULL to use the
848 * device name of @bs.
849 * @bs: Active block device to be committed.
850 * @base: Block device that will be written into, and become the new top.
851 * @creation_flags: Flags that control the behavior of the Job lifetime.
852 * See @BlockJobCreateFlags
853 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
854 * @on_error: The action to take upon error.
855 * @filter_node_name: The node name that should be assigned to the filter
856 * driver that the commit job inserts into the graph above @bs. NULL means that
857 * a node name should be autogenerated.
858 * @cb: Completion function for the job.
859 * @opaque: Opaque pointer value passed to @cb.
860 * @auto_complete: Auto complete the job.
861 * @errp: Error object.
864 void commit_active_start(const char *job_id
, BlockDriverState
*bs
,
865 BlockDriverState
*base
, int creation_flags
,
866 int64_t speed
, BlockdevOnError on_error
,
867 const char *filter_node_name
,
868 BlockCompletionFunc
*cb
, void *opaque
,
869 bool auto_complete
, Error
**errp
);
872 * @job_id: The id of the newly-created job, or %NULL to use the
873 * device name of @bs.
874 * @bs: Block device to operate on.
875 * @target: Block device to write to.
876 * @replaces: Block graph node name to replace once the mirror is done. Can
877 * only be used when full mirroring is selected.
878 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
879 * @granularity: The chosen granularity for the dirty bitmap.
880 * @buf_size: The amount of data that can be in flight at one time.
881 * @mode: Whether to collapse all images in the chain to the target.
882 * @backing_mode: How to establish the target's backing chain after completion.
883 * @on_source_error: The action to take upon error reading from the source.
884 * @on_target_error: The action to take upon error writing to the target.
885 * @unmap: Whether to unmap target where source sectors only contain zeroes.
886 * @filter_node_name: The node name that should be assigned to the filter
887 * driver that the mirror job inserts into the graph above @bs. NULL means that
888 * a node name should be autogenerated.
889 * @errp: Error object.
891 * Start a mirroring operation on @bs. Clusters that are allocated
892 * in @bs will be written to @target until the job is cancelled or
893 * manually completed. At the end of a successful mirroring job,
894 * @bs will be switched to read from @target.
896 void mirror_start(const char *job_id
, BlockDriverState
*bs
,
897 BlockDriverState
*target
, const char *replaces
,
898 int64_t speed
, uint32_t granularity
, int64_t buf_size
,
899 MirrorSyncMode mode
, BlockMirrorBackingMode backing_mode
,
900 BlockdevOnError on_source_error
,
901 BlockdevOnError on_target_error
,
902 bool unmap
, const char *filter_node_name
, Error
**errp
);
906 * @job_id: The id of the newly-created job, or %NULL to use the
907 * device name of @bs.
908 * @bs: Block device to operate on.
909 * @target: Block device to write to.
910 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
911 * @sync_mode: What parts of the disk image should be copied to the destination.
912 * @sync_bitmap: The dirty bitmap if sync_mode is MIRROR_SYNC_MODE_INCREMENTAL.
913 * @on_source_error: The action to take upon error reading from the source.
914 * @on_target_error: The action to take upon error writing to the target.
915 * @creation_flags: Flags that control the behavior of the Job lifetime.
916 * See @BlockJobCreateFlags
917 * @cb: Completion function for the job.
918 * @opaque: Opaque pointer value passed to @cb.
919 * @txn: Transaction that this job is part of (may be NULL).
921 * Create a backup operation on @bs. Clusters in @bs are written to @target
922 * until the job is cancelled or manually completed.
924 BlockJob
*backup_job_create(const char *job_id
, BlockDriverState
*bs
,
925 BlockDriverState
*target
, int64_t speed
,
926 MirrorSyncMode sync_mode
,
927 BdrvDirtyBitmap
*sync_bitmap
,
929 BlockdevOnError on_source_error
,
930 BlockdevOnError on_target_error
,
932 BlockCompletionFunc
*cb
, void *opaque
,
933 BlockJobTxn
*txn
, Error
**errp
);
935 void hmp_drive_add_node(Monitor
*mon
, const char *optstr
);
937 BdrvChild
*bdrv_root_attach_child(BlockDriverState
*child_bs
,
938 const char *child_name
,
939 const BdrvChildRole
*child_role
,
940 uint64_t perm
, uint64_t shared_perm
,
941 void *opaque
, Error
**errp
);
942 void bdrv_root_unref_child(BdrvChild
*child
);
944 int bdrv_child_try_set_perm(BdrvChild
*c
, uint64_t perm
, uint64_t shared
,
947 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by
948 * block filters: Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED and RESIZE to
950 void bdrv_filter_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
951 const BdrvChildRole
*role
,
952 uint64_t perm
, uint64_t shared
,
953 uint64_t *nperm
, uint64_t *nshared
);
955 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by
956 * (non-raw) image formats: Like above for bs->backing, but for bs->file it
957 * requires WRITE | RESIZE for read-write images, always requires
958 * CONSISTENT_READ and doesn't share WRITE. */
959 void bdrv_format_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
960 const BdrvChildRole
*role
,
961 uint64_t perm
, uint64_t shared
,
962 uint64_t *nperm
, uint64_t *nshared
);
964 const char *bdrv_get_parent_name(const BlockDriverState
*bs
);
965 void blk_dev_change_media_cb(BlockBackend
*blk
, bool load
, Error
**errp
);
966 bool blk_dev_has_removable_media(BlockBackend
*blk
);
967 bool blk_dev_has_tray(BlockBackend
*blk
);
968 void blk_dev_eject_request(BlockBackend
*blk
, bool force
);
969 bool blk_dev_is_tray_open(BlockBackend
*blk
);
970 bool blk_dev_is_medium_locked(BlockBackend
*blk
);
972 void bdrv_set_dirty(BlockDriverState
*bs
, int64_t cur_sector
, int64_t nr_sect
);
973 bool bdrv_requests_pending(BlockDriverState
*bs
);
975 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap
*bitmap
, HBitmap
**out
);
976 void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap
*bitmap
, HBitmap
*in
);
978 void bdrv_inc_in_flight(BlockDriverState
*bs
);
979 void bdrv_dec_in_flight(BlockDriverState
*bs
);
981 void blockdev_close_all_bdrv_states(void);
983 #endif /* BLOCK_INT_H */