1 /* 2 * QEMU System Emulator block driver 3 * 4 * Copyright (c) 2003 Fabrice Bellard 5 * 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: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 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 22 * THE SOFTWARE. 23 */ 24 #ifndef BLOCK_INT_H 25 #define BLOCK_INT_H 26 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" 39 40 #define BLOCK_FLAG_ENCRYPT 1 41 #define BLOCK_FLAG_COMPAT6 4 42 #define BLOCK_FLAG_LAZY_REFCOUNTS 8 43 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" 57 58 typedef struct BdrvTrackedRequest { 59 BlockDriverState *bs; 60 int64_t offset; 61 unsigned int bytes; 62 bool is_write; 63 64 bool serialising; 65 int64_t overlap_offset; 66 unsigned int overlap_bytes; 67 68 QLIST_ENTRY(BdrvTrackedRequest) list; 69 Coroutine *co; /* owner, used for deadlock detection */ 70 CoQueue wait_queue; /* coroutines blocked on this request */ 71 72 struct BdrvTrackedRequest *waiting_for; 73 } BdrvTrackedRequest; 74 75 struct BlockDriver { 76 const char *format_name; 77 int instance_size; 78 79 /* set to true if the BlockDriver is a block filter */ 80 bool is_filter; 81 /* for snapshots block filter like Quorum can implement the 82 * following recursive callback. 83 * It's purpose is to recurse on the filter children while calling 84 * bdrv_recurse_is_first_non_filter on them. 85 * For a sample implementation look in the future Quorum block filter. 86 */ 87 bool (*bdrv_recurse_is_first_non_filter)(BlockDriverState *bs, 88 BlockDriverState *candidate); 89 90 int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename); 91 int (*bdrv_probe_device)(const char *filename); 92 93 /* Any driver implementing this callback is expected to be able to handle 94 * NULL file names in its .bdrv_open() implementation */ 95 void (*bdrv_parse_filename)(const char *filename, QDict *options, Error **errp); 96 /* Drivers not implementing bdrv_parse_filename nor bdrv_open should have 97 * this field set to true, except ones that are defined only by their 98 * child's bs. 99 * An example of the last type will be the quorum block driver. 100 */ 101 bool bdrv_needs_filename; 102 103 /* Set if a driver can support backing files */ 104 bool supports_backing; 105 106 /* For handling image reopen for split or non-split files */ 107 int (*bdrv_reopen_prepare)(BDRVReopenState *reopen_state, 108 BlockReopenQueue *queue, Error **errp); 109 void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state); 110 void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state); 111 112 int (*bdrv_open)(BlockDriverState *bs, QDict *options, int flags, 113 Error **errp); 114 int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags, 115 Error **errp); 116 int (*bdrv_read)(BlockDriverState *bs, int64_t sector_num, 117 uint8_t *buf, int nb_sectors); 118 int (*bdrv_write)(BlockDriverState *bs, int64_t sector_num, 119 const uint8_t *buf, int nb_sectors); 120 void (*bdrv_close)(BlockDriverState *bs); 121 void (*bdrv_rebind)(BlockDriverState *bs); 122 int (*bdrv_create)(const char *filename, QemuOpts *opts, Error **errp); 123 int (*bdrv_set_key)(BlockDriverState *bs, const char *key); 124 int (*bdrv_make_empty)(BlockDriverState *bs); 125 /* aio */ 126 BlockDriverAIOCB *(*bdrv_aio_readv)(BlockDriverState *bs, 127 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 128 BlockDriverCompletionFunc *cb, void *opaque); 129 BlockDriverAIOCB *(*bdrv_aio_writev)(BlockDriverState *bs, 130 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 131 BlockDriverCompletionFunc *cb, void *opaque); 132 BlockDriverAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs, 133 BlockDriverCompletionFunc *cb, void *opaque); 134 BlockDriverAIOCB *(*bdrv_aio_discard)(BlockDriverState *bs, 135 int64_t sector_num, int nb_sectors, 136 BlockDriverCompletionFunc *cb, void *opaque); 137 138 int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs, 139 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); 140 int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs, 141 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); 142 /* 143 * Efficiently zero a region of the disk image. Typically an image format 144 * would use a compact metadata representation to implement this. This 145 * function pointer may be NULL and .bdrv_co_writev() will be called 146 * instead. 147 */ 148 int coroutine_fn (*bdrv_co_write_zeroes)(BlockDriverState *bs, 149 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags); 150 int coroutine_fn (*bdrv_co_discard)(BlockDriverState *bs, 151 int64_t sector_num, int nb_sectors); 152 int64_t coroutine_fn (*bdrv_co_get_block_status)(BlockDriverState *bs, 153 int64_t sector_num, int nb_sectors, int *pnum); 154 155 /* 156 * Invalidate any cached meta-data. 157 */ 158 void (*bdrv_invalidate_cache)(BlockDriverState *bs, Error **errp); 159 160 /* 161 * Flushes all data that was already written to the OS all the way down to 162 * the disk (for example raw-posix calls fsync()). 163 */ 164 int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs); 165 166 /* 167 * Flushes all internal caches to the OS. The data may still sit in a 168 * writeback cache of the host OS, but it will survive a crash of the qemu 169 * process. 170 */ 171 int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs); 172 173 const char *protocol_name; 174 int (*bdrv_truncate)(BlockDriverState *bs, int64_t offset); 175 176 int64_t (*bdrv_getlength)(BlockDriverState *bs); 177 bool has_variable_length; 178 int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs); 179 180 int (*bdrv_write_compressed)(BlockDriverState *bs, int64_t sector_num, 181 const uint8_t *buf, int nb_sectors); 182 183 int (*bdrv_snapshot_create)(BlockDriverState *bs, 184 QEMUSnapshotInfo *sn_info); 185 int (*bdrv_snapshot_goto)(BlockDriverState *bs, 186 const char *snapshot_id); 187 int (*bdrv_snapshot_delete)(BlockDriverState *bs, 188 const char *snapshot_id, 189 const char *name, 190 Error **errp); 191 int (*bdrv_snapshot_list)(BlockDriverState *bs, 192 QEMUSnapshotInfo **psn_info); 193 int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs, 194 const char *snapshot_id, 195 const char *name, 196 Error **errp); 197 int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi); 198 ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs); 199 200 int (*bdrv_save_vmstate)(BlockDriverState *bs, QEMUIOVector *qiov, 201 int64_t pos); 202 int (*bdrv_load_vmstate)(BlockDriverState *bs, uint8_t *buf, 203 int64_t pos, int size); 204 205 int (*bdrv_change_backing_file)(BlockDriverState *bs, 206 const char *backing_file, const char *backing_fmt); 207 208 /* removable device specific */ 209 int (*bdrv_is_inserted)(BlockDriverState *bs); 210 int (*bdrv_media_changed)(BlockDriverState *bs); 211 void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag); 212 void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked); 213 214 /* to control generic scsi devices */ 215 int (*bdrv_ioctl)(BlockDriverState *bs, unsigned long int req, void *buf); 216 BlockDriverAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs, 217 unsigned long int req, void *buf, 218 BlockDriverCompletionFunc *cb, void *opaque); 219 220 /* List of options for creating images, terminated by name == NULL */ 221 QemuOptsList *create_opts; 222 223 /* 224 * Returns 0 for completed check, -errno for internal errors. 225 * The check results are stored in result. 226 */ 227 int (*bdrv_check)(BlockDriverState* bs, BdrvCheckResult *result, 228 BdrvCheckMode fix); 229 230 int (*bdrv_amend_options)(BlockDriverState *bs, QemuOpts *opts); 231 232 void (*bdrv_debug_event)(BlockDriverState *bs, BlkDebugEvent event); 233 234 /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */ 235 int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event, 236 const char *tag); 237 int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs, 238 const char *tag); 239 int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag); 240 bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag); 241 242 int (*bdrv_refresh_limits)(BlockDriverState *bs); 243 244 /* 245 * Returns 1 if newly created images are guaranteed to contain only 246 * zeros, 0 otherwise. 247 */ 248 int (*bdrv_has_zero_init)(BlockDriverState *bs); 249 250 /* Remove fd handlers, timers, and other event loop callbacks so the event 251 * loop is no longer in use. Called with no in-flight requests and in 252 * depth-first traversal order with parents before child nodes. 253 */ 254 void (*bdrv_detach_aio_context)(BlockDriverState *bs); 255 256 /* Add fd handlers, timers, and other event loop callbacks so I/O requests 257 * can be processed again. Called with no in-flight requests and in 258 * depth-first traversal order with child nodes before parent nodes. 259 */ 260 void (*bdrv_attach_aio_context)(BlockDriverState *bs, 261 AioContext *new_context); 262 263 QLIST_ENTRY(BlockDriver) list; 264 }; 265 266 typedef struct BlockLimits { 267 /* maximum number of sectors that can be discarded at once */ 268 int max_discard; 269 270 /* optimal alignment for discard requests in sectors */ 271 int64_t discard_alignment; 272 273 /* maximum number of sectors that can zeroized at once */ 274 int max_write_zeroes; 275 276 /* optimal alignment for write zeroes requests in sectors */ 277 int64_t write_zeroes_alignment; 278 279 /* optimal transfer length in sectors */ 280 int opt_transfer_length; 281 282 /* memory alignment so that no bounce buffer is needed */ 283 size_t opt_mem_alignment; 284 } BlockLimits; 285 286 typedef struct BdrvOpBlocker BdrvOpBlocker; 287 288 /* 289 * Note: the function bdrv_append() copies and swaps contents of 290 * BlockDriverStates, so if you add new fields to this struct, please 291 * inspect bdrv_append() to determine if the new fields need to be 292 * copied as well. 293 */ 294 struct BlockDriverState { 295 int64_t total_sectors; /* if we are reading a disk image, give its 296 size in sectors */ 297 int read_only; /* if true, the media is read only */ 298 int open_flags; /* flags used to open the file, re-used for re-open */ 299 int encrypted; /* if true, the media is encrypted */ 300 int valid_key; /* if true, a valid encryption key has been set */ 301 int sg; /* if true, the device is a /dev/sg* */ 302 int copy_on_read; /* if true, copy read backing sectors into image 303 note this is a reference count */ 304 305 BlockDriver *drv; /* NULL means no media */ 306 void *opaque; 307 308 void *dev; /* attached device model, if any */ 309 /* TODO change to DeviceState when all users are qdevified */ 310 const BlockDevOps *dev_ops; 311 void *dev_opaque; 312 313 AioContext *aio_context; /* event loop used for fd handlers, timers, etc */ 314 315 char filename[1024]; 316 char backing_file[1024]; /* if non zero, the image is a diff of 317 this file image */ 318 char backing_format[16]; /* if non-zero and backing_file exists */ 319 320 BlockDriverState *backing_hd; 321 BlockDriverState *file; 322 323 NotifierList close_notifiers; 324 325 /* Callback before write request is processed */ 326 NotifierWithReturnList before_write_notifiers; 327 328 /* number of in-flight serialising requests */ 329 unsigned int serialising_in_flight; 330 331 /* I/O throttling */ 332 ThrottleState throttle_state; 333 CoQueue throttled_reqs[2]; 334 bool io_limits_enabled; 335 336 /* I/O stats (display with "info blockstats"). */ 337 uint64_t nr_bytes[BDRV_MAX_IOTYPE]; 338 uint64_t nr_ops[BDRV_MAX_IOTYPE]; 339 uint64_t total_time_ns[BDRV_MAX_IOTYPE]; 340 uint64_t wr_highest_sector; 341 342 /* I/O Limits */ 343 BlockLimits bl; 344 345 /* Whether the disk can expand beyond total_sectors */ 346 int growable; 347 348 /* Whether produces zeros when read beyond eof */ 349 bool zero_beyond_eof; 350 351 /* Alignment requirement for offset/length of I/O requests */ 352 unsigned int request_alignment; 353 354 /* the block size for which the guest device expects atomicity */ 355 int guest_block_size; 356 357 /* do we need to tell the quest if we have a volatile write cache? */ 358 int enable_write_cache; 359 360 /* NOTE: the following infos are only hints for real hardware 361 drivers. They are not used by the block driver */ 362 BlockdevOnError on_read_error, on_write_error; 363 bool iostatus_enabled; 364 BlockDeviceIoStatus iostatus; 365 366 /* the following member gives a name to every node on the bs graph. */ 367 char node_name[32]; 368 /* element of the list of named nodes building the graph */ 369 QTAILQ_ENTRY(BlockDriverState) node_list; 370 /* Device name is the name associated with the "drive" the guest sees */ 371 char device_name[32]; 372 /* element of the list of "drives" the guest sees */ 373 QTAILQ_ENTRY(BlockDriverState) device_list; 374 QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps; 375 int refcnt; 376 377 QLIST_HEAD(, BdrvTrackedRequest) tracked_requests; 378 379 /* operation blockers */ 380 QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; 381 382 /* long-running background operation */ 383 BlockJob *job; 384 385 QDict *options; 386 BlockdevDetectZeroesOptions detect_zeroes; 387 388 /* The error object in use for blocking operations on backing_hd */ 389 Error *backing_blocker; 390 }; 391 392 int get_tmp_filename(char *filename, int size); 393 394 void bdrv_set_io_limits(BlockDriverState *bs, 395 ThrottleConfig *cfg); 396 397 398 /** 399 * bdrv_add_before_write_notifier: 400 * 401 * Register a callback that is invoked before write requests are processed but 402 * after any throttling or waiting for overlapping requests. 403 */ 404 void bdrv_add_before_write_notifier(BlockDriverState *bs, 405 NotifierWithReturn *notifier); 406 407 /** 408 * bdrv_detach_aio_context: 409 * 410 * May be called from .bdrv_detach_aio_context() to detach children from the 411 * current #AioContext. This is only needed by block drivers that manage their 412 * own children. Both ->file and ->backing_hd are automatically handled and 413 * block drivers should not call this function on them explicitly. 414 */ 415 void bdrv_detach_aio_context(BlockDriverState *bs); 416 417 /** 418 * bdrv_attach_aio_context: 419 * 420 * May be called from .bdrv_attach_aio_context() to attach children to the new 421 * #AioContext. This is only needed by block drivers that manage their own 422 * children. Both ->file and ->backing_hd are automatically handled and block 423 * drivers should not call this function on them explicitly. 424 */ 425 void bdrv_attach_aio_context(BlockDriverState *bs, 426 AioContext *new_context); 427 428 #ifdef _WIN32 429 int is_windows_drive(const char *filename); 430 #endif 431 432 /** 433 * stream_start: 434 * @bs: Block device to operate on. 435 * @base: Block device that will become the new base, or %NULL to 436 * flatten the whole backing file chain onto @bs. 437 * @base_id: The file name that will be written to @bs as the new 438 * backing file if the job completes. Ignored if @base is %NULL. 439 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 440 * @on_error: The action to take upon error. 441 * @cb: Completion function for the job. 442 * @opaque: Opaque pointer value passed to @cb. 443 * @errp: Error object. 444 * 445 * Start a streaming operation on @bs. Clusters that are unallocated 446 * in @bs, but allocated in any image between @base and @bs (both 447 * exclusive) will be written to @bs. At the end of a successful 448 * streaming job, the backing file of @bs will be changed to 449 * @base_id in the written image and to @base in the live BlockDriverState. 450 */ 451 void stream_start(BlockDriverState *bs, BlockDriverState *base, 452 const char *base_id, int64_t speed, BlockdevOnError on_error, 453 BlockDriverCompletionFunc *cb, 454 void *opaque, Error **errp); 455 456 /** 457 * commit_start: 458 * @bs: Active block device. 459 * @top: Top block device to be committed. 460 * @base: Block device that will be written into, and become the new top. 461 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 462 * @on_error: The action to take upon error. 463 * @cb: Completion function for the job. 464 * @opaque: Opaque pointer value passed to @cb. 465 * @errp: Error object. 466 * 467 */ 468 void commit_start(BlockDriverState *bs, BlockDriverState *base, 469 BlockDriverState *top, int64_t speed, 470 BlockdevOnError on_error, BlockDriverCompletionFunc *cb, 471 void *opaque, Error **errp); 472 /** 473 * commit_active_start: 474 * @bs: Active block device to be committed. 475 * @base: Block device that will be written into, and become the new top. 476 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 477 * @on_error: The action to take upon error. 478 * @cb: Completion function for the job. 479 * @opaque: Opaque pointer value passed to @cb. 480 * @errp: Error object. 481 * 482 */ 483 void commit_active_start(BlockDriverState *bs, BlockDriverState *base, 484 int64_t speed, 485 BlockdevOnError on_error, 486 BlockDriverCompletionFunc *cb, 487 void *opaque, Error **errp); 488 /* 489 * mirror_start: 490 * @bs: Block device to operate on. 491 * @target: Block device to write to. 492 * @replaces: Block graph node name to replace once the mirror is done. Can 493 * only be used when full mirroring is selected. 494 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 495 * @granularity: The chosen granularity for the dirty bitmap. 496 * @buf_size: The amount of data that can be in flight at one time. 497 * @mode: Whether to collapse all images in the chain to the target. 498 * @on_source_error: The action to take upon error reading from the source. 499 * @on_target_error: The action to take upon error writing to the target. 500 * @cb: Completion function for the job. 501 * @opaque: Opaque pointer value passed to @cb. 502 * @errp: Error object. 503 * 504 * Start a mirroring operation on @bs. Clusters that are allocated 505 * in @bs will be written to @bs until the job is cancelled or 506 * manually completed. At the end of a successful mirroring job, 507 * @bs will be switched to read from @target. 508 */ 509 void mirror_start(BlockDriverState *bs, BlockDriverState *target, 510 const char *replaces, 511 int64_t speed, int64_t granularity, int64_t buf_size, 512 MirrorSyncMode mode, BlockdevOnError on_source_error, 513 BlockdevOnError on_target_error, 514 BlockDriverCompletionFunc *cb, 515 void *opaque, Error **errp); 516 517 /* 518 * backup_start: 519 * @bs: Block device to operate on. 520 * @target: Block device to write to. 521 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 522 * @sync_mode: What parts of the disk image should be copied to the destination. 523 * @on_source_error: The action to take upon error reading from the source. 524 * @on_target_error: The action to take upon error writing to the target. 525 * @cb: Completion function for the job. 526 * @opaque: Opaque pointer value passed to @cb. 527 * 528 * Start a backup operation on @bs. Clusters in @bs are written to @target 529 * until the job is cancelled or manually completed. 530 */ 531 void backup_start(BlockDriverState *bs, BlockDriverState *target, 532 int64_t speed, MirrorSyncMode sync_mode, 533 BlockdevOnError on_source_error, 534 BlockdevOnError on_target_error, 535 BlockDriverCompletionFunc *cb, void *opaque, 536 Error **errp); 537 538 #endif /* BLOCK_INT_H */ 539