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/block.h"
28 #include "qemu/option.h"
29 #include "qemu/queue.h"
30 #include "block/coroutine.h"
31 #include "qemu/timer.h"
32 #include "qapi-types.h"
33 #include "qapi/qmp/qerror.h"
34 #include "monitor/monitor.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_ENCRYPT 1
41 #define BLOCK_FLAG_COMPAT6 4
42 #define BLOCK_FLAG_LAZY_REFCOUNTS 8
44 #define BLOCK_OPT_SIZE "size"
45 #define BLOCK_OPT_ENCRYPT "encryption"
46 #define BLOCK_OPT_COMPAT6 "compat6"
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"
58 typedef struct BdrvTrackedRequest
{
63 QLIST_ENTRY(BdrvTrackedRequest
) list
;
64 Coroutine
*co
; /* owner, used for deadlock detection */
65 CoQueue wait_queue
; /* coroutines blocked on this request */
69 const char *format_name
;
72 /* if not defined external snapshots are allowed
73 * future block filters will query their children to build the response
75 ExtSnapshotPerm (*bdrv_check_ext_snapshot
)(BlockDriverState
*bs
);
77 int (*bdrv_probe
)(const uint8_t *buf
, int buf_size
, const char *filename
);
78 int (*bdrv_probe_device
)(const char *filename
);
80 /* Any driver implementing this callback is expected to be able to handle
81 * NULL file names in its .bdrv_open() implementation */
82 void (*bdrv_parse_filename
)(const char *filename
, QDict
*options
, Error
**errp
);
83 /* Drivers not implementing bdrv_parse_filename nor bdrv_open should have
84 * this field set to true, except ones that are defined only by their
86 * An example of the last type will be the quorum block driver.
88 bool bdrv_needs_filename
;
90 /* For handling image reopen for split or non-split files */
91 int (*bdrv_reopen_prepare
)(BDRVReopenState
*reopen_state
,
92 BlockReopenQueue
*queue
, Error
**errp
);
93 void (*bdrv_reopen_commit
)(BDRVReopenState
*reopen_state
);
94 void (*bdrv_reopen_abort
)(BDRVReopenState
*reopen_state
);
96 int (*bdrv_open
)(BlockDriverState
*bs
, QDict
*options
, int flags
,
98 int (*bdrv_file_open
)(BlockDriverState
*bs
, QDict
*options
, int flags
,
100 int (*bdrv_read
)(BlockDriverState
*bs
, int64_t sector_num
,
101 uint8_t *buf
, int nb_sectors
);
102 int (*bdrv_write
)(BlockDriverState
*bs
, int64_t sector_num
,
103 const uint8_t *buf
, int nb_sectors
);
104 void (*bdrv_close
)(BlockDriverState
*bs
);
105 void (*bdrv_rebind
)(BlockDriverState
*bs
);
106 int (*bdrv_create
)(const char *filename
, QEMUOptionParameter
*options
,
108 int (*bdrv_set_key
)(BlockDriverState
*bs
, const char *key
);
109 int (*bdrv_make_empty
)(BlockDriverState
*bs
);
111 BlockDriverAIOCB
*(*bdrv_aio_readv
)(BlockDriverState
*bs
,
112 int64_t sector_num
, QEMUIOVector
*qiov
, int nb_sectors
,
113 BlockDriverCompletionFunc
*cb
, void *opaque
);
114 BlockDriverAIOCB
*(*bdrv_aio_writev
)(BlockDriverState
*bs
,
115 int64_t sector_num
, QEMUIOVector
*qiov
, int nb_sectors
,
116 BlockDriverCompletionFunc
*cb
, void *opaque
);
117 BlockDriverAIOCB
*(*bdrv_aio_flush
)(BlockDriverState
*bs
,
118 BlockDriverCompletionFunc
*cb
, void *opaque
);
119 BlockDriverAIOCB
*(*bdrv_aio_discard
)(BlockDriverState
*bs
,
120 int64_t sector_num
, int nb_sectors
,
121 BlockDriverCompletionFunc
*cb
, void *opaque
);
123 int coroutine_fn (*bdrv_co_readv
)(BlockDriverState
*bs
,
124 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
);
125 int coroutine_fn (*bdrv_co_writev
)(BlockDriverState
*bs
,
126 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
);
128 * Efficiently zero a region of the disk image. Typically an image format
129 * would use a compact metadata representation to implement this. This
130 * function pointer may be NULL and .bdrv_co_writev() will be called
133 int coroutine_fn (*bdrv_co_write_zeroes
)(BlockDriverState
*bs
,
134 int64_t sector_num
, int nb_sectors
, BdrvRequestFlags flags
);
135 int coroutine_fn (*bdrv_co_discard
)(BlockDriverState
*bs
,
136 int64_t sector_num
, int nb_sectors
);
137 int64_t coroutine_fn (*bdrv_co_get_block_status
)(BlockDriverState
*bs
,
138 int64_t sector_num
, int nb_sectors
, int *pnum
);
141 * Invalidate any cached meta-data.
143 void (*bdrv_invalidate_cache
)(BlockDriverState
*bs
);
146 * Flushes all data that was already written to the OS all the way down to
147 * the disk (for example raw-posix calls fsync()).
149 int coroutine_fn (*bdrv_co_flush_to_disk
)(BlockDriverState
*bs
);
152 * Flushes all internal caches to the OS. The data may still sit in a
153 * writeback cache of the host OS, but it will survive a crash of the qemu
156 int coroutine_fn (*bdrv_co_flush_to_os
)(BlockDriverState
*bs
);
158 const char *protocol_name
;
159 int (*bdrv_truncate
)(BlockDriverState
*bs
, int64_t offset
);
161 int64_t (*bdrv_getlength
)(BlockDriverState
*bs
);
162 bool has_variable_length
;
163 int64_t (*bdrv_get_allocated_file_size
)(BlockDriverState
*bs
);
165 int (*bdrv_write_compressed
)(BlockDriverState
*bs
, int64_t sector_num
,
166 const uint8_t *buf
, int nb_sectors
);
168 int (*bdrv_snapshot_create
)(BlockDriverState
*bs
,
169 QEMUSnapshotInfo
*sn_info
);
170 int (*bdrv_snapshot_goto
)(BlockDriverState
*bs
,
171 const char *snapshot_id
);
172 int (*bdrv_snapshot_delete
)(BlockDriverState
*bs
,
173 const char *snapshot_id
,
176 int (*bdrv_snapshot_list
)(BlockDriverState
*bs
,
177 QEMUSnapshotInfo
**psn_info
);
178 int (*bdrv_snapshot_load_tmp
)(BlockDriverState
*bs
,
179 const char *snapshot_name
);
180 int (*bdrv_get_info
)(BlockDriverState
*bs
, BlockDriverInfo
*bdi
);
181 ImageInfoSpecific
*(*bdrv_get_specific_info
)(BlockDriverState
*bs
);
183 int (*bdrv_save_vmstate
)(BlockDriverState
*bs
, QEMUIOVector
*qiov
,
185 int (*bdrv_load_vmstate
)(BlockDriverState
*bs
, uint8_t *buf
,
186 int64_t pos
, int size
);
188 int (*bdrv_change_backing_file
)(BlockDriverState
*bs
,
189 const char *backing_file
, const char *backing_fmt
);
191 /* removable device specific */
192 int (*bdrv_is_inserted
)(BlockDriverState
*bs
);
193 int (*bdrv_media_changed
)(BlockDriverState
*bs
);
194 void (*bdrv_eject
)(BlockDriverState
*bs
, bool eject_flag
);
195 void (*bdrv_lock_medium
)(BlockDriverState
*bs
, bool locked
);
197 /* to control generic scsi devices */
198 int (*bdrv_ioctl
)(BlockDriverState
*bs
, unsigned long int req
, void *buf
);
199 BlockDriverAIOCB
*(*bdrv_aio_ioctl
)(BlockDriverState
*bs
,
200 unsigned long int req
, void *buf
,
201 BlockDriverCompletionFunc
*cb
, void *opaque
);
203 /* List of options for creating images, terminated by name == NULL */
204 QEMUOptionParameter
*create_options
;
208 * Returns 0 for completed check, -errno for internal errors.
209 * The check results are stored in result.
211 int (*bdrv_check
)(BlockDriverState
* bs
, BdrvCheckResult
*result
,
214 int (*bdrv_amend_options
)(BlockDriverState
*bs
,
215 QEMUOptionParameter
*options
);
217 void (*bdrv_debug_event
)(BlockDriverState
*bs
, BlkDebugEvent event
);
219 /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */
220 int (*bdrv_debug_breakpoint
)(BlockDriverState
*bs
, const char *event
,
222 int (*bdrv_debug_remove_breakpoint
)(BlockDriverState
*bs
,
224 int (*bdrv_debug_resume
)(BlockDriverState
*bs
, const char *tag
);
225 bool (*bdrv_debug_is_suspended
)(BlockDriverState
*bs
, const char *tag
);
228 * Returns 1 if newly created images are guaranteed to contain only
229 * zeros, 0 otherwise.
231 int (*bdrv_has_zero_init
)(BlockDriverState
*bs
);
233 QLIST_ENTRY(BlockDriver
) list
;
236 typedef struct BlockLimits
{
237 /* maximum number of sectors that can be discarded at once */
240 /* optimal alignment for discard requests in sectors */
241 int64_t discard_alignment
;
243 /* maximum number of sectors that can zeroized at once */
244 int max_write_zeroes
;
246 /* optimal alignment for write zeroes requests in sectors */
247 int64_t write_zeroes_alignment
;
251 * Note: the function bdrv_append() copies and swaps contents of
252 * BlockDriverStates, so if you add new fields to this struct, please
253 * inspect bdrv_append() to determine if the new fields need to be
256 struct BlockDriverState
{
257 int64_t total_sectors
; /* if we are reading a disk image, give its
259 int read_only
; /* if true, the media is read only */
260 int open_flags
; /* flags used to open the file, re-used for re-open */
261 int encrypted
; /* if true, the media is encrypted */
262 int valid_key
; /* if true, a valid encryption key has been set */
263 int sg
; /* if true, the device is a /dev/sg* */
264 int copy_on_read
; /* if true, copy read backing sectors into image
265 note this is a reference count */
267 BlockDriver
*drv
; /* NULL means no media */
270 void *dev
; /* attached device model, if any */
271 /* TODO change to DeviceState when all users are qdevified */
272 const BlockDevOps
*dev_ops
;
276 char backing_file
[1024]; /* if non zero, the image is a diff of
278 char backing_format
[16]; /* if non-zero and backing_file exists */
281 BlockDriverState
*backing_hd
;
282 BlockDriverState
*file
;
284 NotifierList close_notifiers
;
286 /* Callback before write request is processed */
287 NotifierWithReturnList before_write_notifiers
;
289 /* number of in-flight copy-on-read requests */
290 unsigned int copy_on_read_in_flight
;
293 ThrottleState throttle_state
;
294 CoQueue throttled_reqs
[2];
295 bool io_limits_enabled
;
297 /* I/O stats (display with "info blockstats"). */
298 uint64_t nr_bytes
[BDRV_MAX_IOTYPE
];
299 uint64_t nr_ops
[BDRV_MAX_IOTYPE
];
300 uint64_t total_time_ns
[BDRV_MAX_IOTYPE
];
301 uint64_t wr_highest_sector
;
306 /* Whether the disk can expand beyond total_sectors */
309 /* Whether produces zeros when read beyond eof */
310 bool zero_beyond_eof
;
312 /* the memory alignment required for the buffers handled by this driver */
313 int buffer_alignment
;
315 /* do we need to tell the quest if we have a volatile write cache? */
316 int enable_write_cache
;
318 /* NOTE: the following infos are only hints for real hardware
319 drivers. They are not used by the block driver */
320 BlockdevOnError on_read_error
, on_write_error
;
321 bool iostatus_enabled
;
322 BlockDeviceIoStatus iostatus
;
323 char device_name
[32];
324 QLIST_HEAD(, BdrvDirtyBitmap
) dirty_bitmaps
;
326 int in_use
; /* users other than guest access, eg. block migration */
327 QTAILQ_ENTRY(BlockDriverState
) list
;
329 QLIST_HEAD(, BdrvTrackedRequest
) tracked_requests
;
331 /* long-running background operation */
337 int get_tmp_filename(char *filename
, int size
);
339 void bdrv_set_io_limits(BlockDriverState
*bs
,
340 ThrottleConfig
*cfg
);
344 * bdrv_add_before_write_notifier:
346 * Register a callback that is invoked before write requests are processed but
347 * after any throttling or waiting for overlapping requests.
349 void bdrv_add_before_write_notifier(BlockDriverState
*bs
,
350 NotifierWithReturn
*notifier
);
353 * bdrv_get_aio_context:
355 * Returns: the currently bound #AioContext
357 AioContext
*bdrv_get_aio_context(BlockDriverState
*bs
);
360 int is_windows_drive(const char *filename
);
362 void bdrv_emit_qmp_error_event(const BlockDriverState
*bdrv
,
363 enum MonitorEvent ev
,
364 BlockErrorAction action
, bool is_read
);
368 * @bs: Block device to operate on.
369 * @base: Block device that will become the new base, or %NULL to
370 * flatten the whole backing file chain onto @bs.
371 * @base_id: The file name that will be written to @bs as the new
372 * backing file if the job completes. Ignored if @base is %NULL.
373 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
374 * @on_error: The action to take upon error.
375 * @cb: Completion function for the job.
376 * @opaque: Opaque pointer value passed to @cb.
377 * @errp: Error object.
379 * Start a streaming operation on @bs. Clusters that are unallocated
380 * in @bs, but allocated in any image between @base and @bs (both
381 * exclusive) will be written to @bs. At the end of a successful
382 * streaming job, the backing file of @bs will be changed to
383 * @base_id in the written image and to @base in the live BlockDriverState.
385 void stream_start(BlockDriverState
*bs
, BlockDriverState
*base
,
386 const char *base_id
, int64_t speed
, BlockdevOnError on_error
,
387 BlockDriverCompletionFunc
*cb
,
388 void *opaque
, Error
**errp
);
392 * @bs: Top Block device
393 * @base: Block device that will be written into, and become the new top
394 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
395 * @on_error: The action to take upon error.
396 * @cb: Completion function for the job.
397 * @opaque: Opaque pointer value passed to @cb.
398 * @errp: Error object.
401 void commit_start(BlockDriverState
*bs
, BlockDriverState
*base
,
402 BlockDriverState
*top
, int64_t speed
,
403 BlockdevOnError on_error
, BlockDriverCompletionFunc
*cb
,
404 void *opaque
, Error
**errp
);
408 * @bs: Block device to operate on.
409 * @target: Block device to write to.
410 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
411 * @granularity: The chosen granularity for the dirty bitmap.
412 * @buf_size: The amount of data that can be in flight at one time.
413 * @mode: Whether to collapse all images in the chain to the target.
414 * @on_source_error: The action to take upon error reading from the source.
415 * @on_target_error: The action to take upon error writing to the target.
416 * @cb: Completion function for the job.
417 * @opaque: Opaque pointer value passed to @cb.
418 * @errp: Error object.
420 * Start a mirroring operation on @bs. Clusters that are allocated
421 * in @bs will be written to @bs until the job is cancelled or
422 * manually completed. At the end of a successful mirroring job,
423 * @bs will be switched to read from @target.
425 void mirror_start(BlockDriverState
*bs
, BlockDriverState
*target
,
426 int64_t speed
, int64_t granularity
, int64_t buf_size
,
427 MirrorSyncMode mode
, BlockdevOnError on_source_error
,
428 BlockdevOnError on_target_error
,
429 BlockDriverCompletionFunc
*cb
,
430 void *opaque
, Error
**errp
);
434 * @bs: Block device to operate on.
435 * @target: Block device to write to.
436 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
437 * @sync_mode: What parts of the disk image should be copied to the destination.
438 * @on_source_error: The action to take upon error reading from the source.
439 * @on_target_error: The action to take upon error writing to the target.
440 * @cb: Completion function for the job.
441 * @opaque: Opaque pointer value passed to @cb.
443 * Start a backup operation on @bs. Clusters in @bs are written to @target
444 * until the job is cancelled or manually completed.
446 void backup_start(BlockDriverState
*bs
, BlockDriverState
*target
,
447 int64_t speed
, MirrorSyncMode sync_mode
,
448 BlockdevOnError on_source_error
,
449 BlockdevOnError on_target_error
,
450 BlockDriverCompletionFunc
*cb
, void *opaque
,
453 #endif /* BLOCK_INT_H */