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/accounting.h" 28 #include "block/block.h" 29 #include "block/aio-wait.h" 30 #include "qemu/queue.h" 31 #include "qemu/coroutine.h" 32 #include "qemu/stats64.h" 33 #include "qemu/timer.h" 34 #include "qemu/hbitmap.h" 35 #include "block/snapshot.h" 36 #include "qemu/throttle.h" 37 #include "qemu/rcu.h" 38 39 #define BLOCK_FLAG_LAZY_REFCOUNTS 8 40 41 #define BLOCK_OPT_SIZE "size" 42 #define BLOCK_OPT_ENCRYPT "encryption" 43 #define BLOCK_OPT_ENCRYPT_FORMAT "encrypt.format" 44 #define BLOCK_OPT_COMPAT6 "compat6" 45 #define BLOCK_OPT_HWVERSION "hwversion" 46 #define BLOCK_OPT_BACKING_FILE "backing_file" 47 #define BLOCK_OPT_BACKING_FMT "backing_fmt" 48 #define BLOCK_OPT_CLUSTER_SIZE "cluster_size" 49 #define BLOCK_OPT_TABLE_SIZE "table_size" 50 #define BLOCK_OPT_PREALLOC "preallocation" 51 #define BLOCK_OPT_SUBFMT "subformat" 52 #define BLOCK_OPT_COMPAT_LEVEL "compat" 53 #define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts" 54 #define BLOCK_OPT_ADAPTER_TYPE "adapter_type" 55 #define BLOCK_OPT_REDUNDANCY "redundancy" 56 #define BLOCK_OPT_NOCOW "nocow" 57 #define BLOCK_OPT_EXTENT_SIZE_HINT "extent_size_hint" 58 #define BLOCK_OPT_OBJECT_SIZE "object_size" 59 #define BLOCK_OPT_REFCOUNT_BITS "refcount_bits" 60 #define BLOCK_OPT_DATA_FILE "data_file" 61 #define BLOCK_OPT_DATA_FILE_RAW "data_file_raw" 62 #define BLOCK_OPT_COMPRESSION_TYPE "compression_type" 63 #define BLOCK_OPT_EXTL2 "extended_l2" 64 65 #define BLOCK_PROBE_BUF_SIZE 512 66 67 enum BdrvTrackedRequestType { 68 BDRV_TRACKED_READ, 69 BDRV_TRACKED_WRITE, 70 BDRV_TRACKED_DISCARD, 71 BDRV_TRACKED_TRUNCATE, 72 }; 73 74 /* 75 * That is not quite good that BdrvTrackedRequest structure is public, 76 * as block/io.c is very careful about incoming offset/bytes being 77 * correct. Be sure to assert bdrv_check_request() succeeded after any 78 * modification of BdrvTrackedRequest object out of block/io.c 79 */ 80 typedef struct BdrvTrackedRequest { 81 BlockDriverState *bs; 82 int64_t offset; 83 int64_t bytes; 84 enum BdrvTrackedRequestType type; 85 86 bool serialising; 87 int64_t overlap_offset; 88 int64_t overlap_bytes; 89 90 QLIST_ENTRY(BdrvTrackedRequest) list; 91 Coroutine *co; /* owner, used for deadlock detection */ 92 CoQueue wait_queue; /* coroutines blocked on this request */ 93 94 struct BdrvTrackedRequest *waiting_for; 95 } BdrvTrackedRequest; 96 97 int bdrv_check_qiov_request(int64_t offset, int64_t bytes, 98 QEMUIOVector *qiov, size_t qiov_offset, 99 Error **errp); 100 int bdrv_check_request(int64_t offset, int64_t bytes, Error **errp); 101 102 struct BlockDriver { 103 const char *format_name; 104 int instance_size; 105 106 /* set to true if the BlockDriver is a block filter. Block filters pass 107 * certain callbacks that refer to data (see block.c) to their bs->file 108 * or bs->backing (whichever one exists) if the driver doesn't implement 109 * them. Drivers that do not wish to forward must implement them and return 110 * -ENOTSUP. 111 * Note that filters are not allowed to modify data. 112 * 113 * Filters generally cannot have more than a single filtered child, 114 * because the data they present must at all times be the same as 115 * that on their filtered child. That would be impossible to 116 * achieve for multiple filtered children. 117 * (And this filtered child must then be bs->file or bs->backing.) 118 */ 119 bool is_filter; 120 /* 121 * Set to true if the BlockDriver is a format driver. Format nodes 122 * generally do not expect their children to be other format nodes 123 * (except for backing files), and so format probing is disabled 124 * on those children. 125 */ 126 bool is_format; 127 /* 128 * Return true if @to_replace can be replaced by a BDS with the 129 * same data as @bs without it affecting @bs's behavior (that is, 130 * without it being visible to @bs's parents). 131 */ 132 bool (*bdrv_recurse_can_replace)(BlockDriverState *bs, 133 BlockDriverState *to_replace); 134 135 int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename); 136 int (*bdrv_probe_device)(const char *filename); 137 138 /* Any driver implementing this callback is expected to be able to handle 139 * NULL file names in its .bdrv_open() implementation */ 140 void (*bdrv_parse_filename)(const char *filename, QDict *options, Error **errp); 141 /* Drivers not implementing bdrv_parse_filename nor bdrv_open should have 142 * this field set to true, except ones that are defined only by their 143 * child's bs. 144 * An example of the last type will be the quorum block driver. 145 */ 146 bool bdrv_needs_filename; 147 148 /* 149 * Set if a driver can support backing files. This also implies the 150 * following semantics: 151 * 152 * - Return status 0 of .bdrv_co_block_status means that corresponding 153 * blocks are not allocated in this layer of backing-chain 154 * - For such (unallocated) blocks, read will: 155 * - fill buffer with zeros if there is no backing file 156 * - read from the backing file otherwise, where the block layer 157 * takes care of reading zeros beyond EOF if backing file is short 158 */ 159 bool supports_backing; 160 161 /* For handling image reopen for split or non-split files */ 162 int (*bdrv_reopen_prepare)(BDRVReopenState *reopen_state, 163 BlockReopenQueue *queue, Error **errp); 164 void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state); 165 void (*bdrv_reopen_commit_post)(BDRVReopenState *reopen_state); 166 void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state); 167 void (*bdrv_join_options)(QDict *options, QDict *old_options); 168 169 int (*bdrv_open)(BlockDriverState *bs, QDict *options, int flags, 170 Error **errp); 171 172 /* Protocol drivers should implement this instead of bdrv_open */ 173 int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags, 174 Error **errp); 175 void (*bdrv_close)(BlockDriverState *bs); 176 177 178 int coroutine_fn (*bdrv_co_create)(BlockdevCreateOptions *opts, 179 Error **errp); 180 int coroutine_fn (*bdrv_co_create_opts)(BlockDriver *drv, 181 const char *filename, 182 QemuOpts *opts, 183 Error **errp); 184 185 int coroutine_fn (*bdrv_co_amend)(BlockDriverState *bs, 186 BlockdevAmendOptions *opts, 187 bool force, 188 Error **errp); 189 190 int (*bdrv_amend_options)(BlockDriverState *bs, 191 QemuOpts *opts, 192 BlockDriverAmendStatusCB *status_cb, 193 void *cb_opaque, 194 bool force, 195 Error **errp); 196 197 int (*bdrv_make_empty)(BlockDriverState *bs); 198 199 /* 200 * Refreshes the bs->exact_filename field. If that is impossible, 201 * bs->exact_filename has to be left empty. 202 */ 203 void (*bdrv_refresh_filename)(BlockDriverState *bs); 204 205 /* 206 * Gathers the open options for all children into @target. 207 * A simple format driver (without backing file support) might 208 * implement this function like this: 209 * 210 * QINCREF(bs->file->bs->full_open_options); 211 * qdict_put(target, "file", bs->file->bs->full_open_options); 212 * 213 * If not specified, the generic implementation will simply put 214 * all children's options under their respective name. 215 * 216 * @backing_overridden is true when bs->backing seems not to be 217 * the child that would result from opening bs->backing_file. 218 * Therefore, if it is true, the backing child's options should be 219 * gathered; otherwise, there is no need since the backing child 220 * is the one implied by the image header. 221 * 222 * Note that ideally this function would not be needed. Every 223 * block driver which implements it is probably doing something 224 * shady regarding its runtime option structure. 225 */ 226 void (*bdrv_gather_child_options)(BlockDriverState *bs, QDict *target, 227 bool backing_overridden); 228 229 /* 230 * Returns an allocated string which is the directory name of this BDS: It 231 * will be used to make relative filenames absolute by prepending this 232 * function's return value to them. 233 */ 234 char *(*bdrv_dirname)(BlockDriverState *bs, Error **errp); 235 236 /* aio */ 237 BlockAIOCB *(*bdrv_aio_preadv)(BlockDriverState *bs, 238 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 239 BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); 240 BlockAIOCB *(*bdrv_aio_pwritev)(BlockDriverState *bs, 241 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 242 BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); 243 BlockAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs, 244 BlockCompletionFunc *cb, void *opaque); 245 BlockAIOCB *(*bdrv_aio_pdiscard)(BlockDriverState *bs, 246 int64_t offset, int bytes, 247 BlockCompletionFunc *cb, void *opaque); 248 249 int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs, 250 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); 251 252 /** 253 * @offset: position in bytes to read at 254 * @bytes: number of bytes to read 255 * @qiov: the buffers to fill with read data 256 * @flags: currently unused, always 0 257 * 258 * @offset and @bytes will be a multiple of 'request_alignment', 259 * but the length of individual @qiov elements does not have to 260 * be a multiple. 261 * 262 * @bytes will always equal the total size of @qiov, and will be 263 * no larger than 'max_transfer'. 264 * 265 * The buffer in @qiov may point directly to guest memory. 266 */ 267 int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs, 268 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 269 BdrvRequestFlags flags); 270 int coroutine_fn (*bdrv_co_preadv_part)(BlockDriverState *bs, 271 int64_t offset, int64_t bytes, 272 QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags); 273 int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs, 274 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int flags); 275 /** 276 * @offset: position in bytes to write at 277 * @bytes: number of bytes to write 278 * @qiov: the buffers containing data to write 279 * @flags: zero or more bits allowed by 'supported_write_flags' 280 * 281 * @offset and @bytes will be a multiple of 'request_alignment', 282 * but the length of individual @qiov elements does not have to 283 * be a multiple. 284 * 285 * @bytes will always equal the total size of @qiov, and will be 286 * no larger than 'max_transfer'. 287 * 288 * The buffer in @qiov may point directly to guest memory. 289 */ 290 int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs, 291 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 292 BdrvRequestFlags flags); 293 int coroutine_fn (*bdrv_co_pwritev_part)(BlockDriverState *bs, 294 int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset, 295 BdrvRequestFlags flags); 296 297 /* 298 * Efficiently zero a region of the disk image. Typically an image format 299 * would use a compact metadata representation to implement this. This 300 * function pointer may be NULL or return -ENOSUP and .bdrv_co_writev() 301 * will be called instead. 302 */ 303 int coroutine_fn (*bdrv_co_pwrite_zeroes)(BlockDriverState *bs, 304 int64_t offset, int64_t bytes, BdrvRequestFlags flags); 305 int coroutine_fn (*bdrv_co_pdiscard)(BlockDriverState *bs, 306 int64_t offset, int64_t bytes); 307 308 /* Map [offset, offset + nbytes) range onto a child of @bs to copy from, 309 * and invoke bdrv_co_copy_range_from(child, ...), or invoke 310 * bdrv_co_copy_range_to() if @bs is the leaf child to copy data from. 311 * 312 * See the comment of bdrv_co_copy_range for the parameter and return value 313 * semantics. 314 */ 315 int coroutine_fn (*bdrv_co_copy_range_from)(BlockDriverState *bs, 316 BdrvChild *src, 317 int64_t offset, 318 BdrvChild *dst, 319 int64_t dst_offset, 320 int64_t bytes, 321 BdrvRequestFlags read_flags, 322 BdrvRequestFlags write_flags); 323 324 /* Map [offset, offset + nbytes) range onto a child of bs to copy data to, 325 * and invoke bdrv_co_copy_range_to(child, src, ...), or perform the copy 326 * operation if @bs is the leaf and @src has the same BlockDriver. Return 327 * -ENOTSUP if @bs is the leaf but @src has a different BlockDriver. 328 * 329 * See the comment of bdrv_co_copy_range for the parameter and return value 330 * semantics. 331 */ 332 int coroutine_fn (*bdrv_co_copy_range_to)(BlockDriverState *bs, 333 BdrvChild *src, 334 int64_t src_offset, 335 BdrvChild *dst, 336 int64_t dst_offset, 337 int64_t bytes, 338 BdrvRequestFlags read_flags, 339 BdrvRequestFlags write_flags); 340 341 /* 342 * Building block for bdrv_block_status[_above] and 343 * bdrv_is_allocated[_above]. The driver should answer only 344 * according to the current layer, and should only need to set 345 * BDRV_BLOCK_DATA, BDRV_BLOCK_ZERO, BDRV_BLOCK_OFFSET_VALID, 346 * and/or BDRV_BLOCK_RAW; if the current layer defers to a backing 347 * layer, the result should be 0 (and not BDRV_BLOCK_ZERO). See 348 * block.h for the overall meaning of the bits. As a hint, the 349 * flag want_zero is true if the caller cares more about precise 350 * mappings (favor accurate _OFFSET_VALID/_ZERO) or false for 351 * overall allocation (favor larger *pnum, perhaps by reporting 352 * _DATA instead of _ZERO). The block layer guarantees input 353 * clamped to bdrv_getlength() and aligned to request_alignment, 354 * as well as non-NULL pnum, map, and file; in turn, the driver 355 * must return an error or set pnum to an aligned non-zero value. 356 * 357 * Note that @bytes is just a hint on how big of a region the 358 * caller wants to inspect. It is not a limit on *pnum. 359 * Implementations are free to return larger values of *pnum if 360 * doing so does not incur a performance penalty. 361 * 362 * block/io.c's bdrv_co_block_status() will utilize an unclamped 363 * *pnum value for the block-status cache on protocol nodes, prior 364 * to clamping *pnum for return to its caller. 365 */ 366 int coroutine_fn (*bdrv_co_block_status)(BlockDriverState *bs, 367 bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum, 368 int64_t *map, BlockDriverState **file); 369 370 /* 371 * This informs the driver that we are no longer interested in the result 372 * of in-flight requests, so don't waste the time if possible. 373 * 374 * One example usage is to avoid waiting for an nbd target node reconnect 375 * timeout during job-cancel with force=true. 376 */ 377 void (*bdrv_cancel_in_flight)(BlockDriverState *bs); 378 379 /* 380 * Invalidate any cached meta-data. 381 */ 382 void coroutine_fn (*bdrv_co_invalidate_cache)(BlockDriverState *bs, 383 Error **errp); 384 int (*bdrv_inactivate)(BlockDriverState *bs); 385 386 /* 387 * Flushes all data for all layers by calling bdrv_co_flush for underlying 388 * layers, if needed. This function is needed for deterministic 389 * synchronization of the flush finishing callback. 390 */ 391 int coroutine_fn (*bdrv_co_flush)(BlockDriverState *bs); 392 393 /* Delete a created file. */ 394 int coroutine_fn (*bdrv_co_delete_file)(BlockDriverState *bs, 395 Error **errp); 396 397 /* 398 * Flushes all data that was already written to the OS all the way down to 399 * the disk (for example file-posix.c calls fsync()). 400 */ 401 int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs); 402 403 /* 404 * Flushes all internal caches to the OS. The data may still sit in a 405 * writeback cache of the host OS, but it will survive a crash of the qemu 406 * process. 407 */ 408 int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs); 409 410 /* 411 * Drivers setting this field must be able to work with just a plain 412 * filename with '<protocol_name>:' as a prefix, and no other options. 413 * Options may be extracted from the filename by implementing 414 * bdrv_parse_filename. 415 */ 416 const char *protocol_name; 417 418 /* 419 * Truncate @bs to @offset bytes using the given @prealloc mode 420 * when growing. Modes other than PREALLOC_MODE_OFF should be 421 * rejected when shrinking @bs. 422 * 423 * If @exact is true, @bs must be resized to exactly @offset. 424 * Otherwise, it is sufficient for @bs (if it is a host block 425 * device and thus there is no way to resize it) to be at least 426 * @offset bytes in length. 427 * 428 * If @exact is true and this function fails but would succeed 429 * with @exact = false, it should return -ENOTSUP. 430 */ 431 int coroutine_fn (*bdrv_co_truncate)(BlockDriverState *bs, int64_t offset, 432 bool exact, PreallocMode prealloc, 433 BdrvRequestFlags flags, Error **errp); 434 435 int64_t (*bdrv_getlength)(BlockDriverState *bs); 436 bool has_variable_length; 437 int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs); 438 BlockMeasureInfo *(*bdrv_measure)(QemuOpts *opts, BlockDriverState *in_bs, 439 Error **errp); 440 441 int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs, 442 int64_t offset, int64_t bytes, QEMUIOVector *qiov); 443 int coroutine_fn (*bdrv_co_pwritev_compressed_part)(BlockDriverState *bs, 444 int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset); 445 446 int (*bdrv_snapshot_create)(BlockDriverState *bs, 447 QEMUSnapshotInfo *sn_info); 448 int (*bdrv_snapshot_goto)(BlockDriverState *bs, 449 const char *snapshot_id); 450 int (*bdrv_snapshot_delete)(BlockDriverState *bs, 451 const char *snapshot_id, 452 const char *name, 453 Error **errp); 454 int (*bdrv_snapshot_list)(BlockDriverState *bs, 455 QEMUSnapshotInfo **psn_info); 456 int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs, 457 const char *snapshot_id, 458 const char *name, 459 Error **errp); 460 int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi); 461 ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs, 462 Error **errp); 463 BlockStatsSpecific *(*bdrv_get_specific_stats)(BlockDriverState *bs); 464 465 int coroutine_fn (*bdrv_save_vmstate)(BlockDriverState *bs, 466 QEMUIOVector *qiov, 467 int64_t pos); 468 int coroutine_fn (*bdrv_load_vmstate)(BlockDriverState *bs, 469 QEMUIOVector *qiov, 470 int64_t pos); 471 472 int (*bdrv_change_backing_file)(BlockDriverState *bs, 473 const char *backing_file, const char *backing_fmt); 474 475 /* removable device specific */ 476 bool (*bdrv_is_inserted)(BlockDriverState *bs); 477 void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag); 478 void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked); 479 480 /* to control generic scsi devices */ 481 BlockAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs, 482 unsigned long int req, void *buf, 483 BlockCompletionFunc *cb, void *opaque); 484 int coroutine_fn (*bdrv_co_ioctl)(BlockDriverState *bs, 485 unsigned long int req, void *buf); 486 487 /* List of options for creating images, terminated by name == NULL */ 488 QemuOptsList *create_opts; 489 490 /* List of options for image amend */ 491 QemuOptsList *amend_opts; 492 493 /* 494 * If this driver supports reopening images this contains a 495 * NULL-terminated list of the runtime options that can be 496 * modified. If an option in this list is unspecified during 497 * reopen then it _must_ be reset to its default value or return 498 * an error. 499 */ 500 const char *const *mutable_opts; 501 502 /* 503 * Returns 0 for completed check, -errno for internal errors. 504 * The check results are stored in result. 505 */ 506 int coroutine_fn (*bdrv_co_check)(BlockDriverState *bs, 507 BdrvCheckResult *result, 508 BdrvCheckMode fix); 509 510 void (*bdrv_debug_event)(BlockDriverState *bs, BlkdebugEvent event); 511 512 /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */ 513 int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event, 514 const char *tag); 515 int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs, 516 const char *tag); 517 int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag); 518 bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag); 519 520 void (*bdrv_refresh_limits)(BlockDriverState *bs, Error **errp); 521 522 /* 523 * Returns 1 if newly created images are guaranteed to contain only 524 * zeros, 0 otherwise. 525 */ 526 int (*bdrv_has_zero_init)(BlockDriverState *bs); 527 528 /* Remove fd handlers, timers, and other event loop callbacks so the event 529 * loop is no longer in use. Called with no in-flight requests and in 530 * depth-first traversal order with parents before child nodes. 531 */ 532 void (*bdrv_detach_aio_context)(BlockDriverState *bs); 533 534 /* Add fd handlers, timers, and other event loop callbacks so I/O requests 535 * can be processed again. Called with no in-flight requests and in 536 * depth-first traversal order with child nodes before parent nodes. 537 */ 538 void (*bdrv_attach_aio_context)(BlockDriverState *bs, 539 AioContext *new_context); 540 541 /* io queue for linux-aio */ 542 void (*bdrv_io_plug)(BlockDriverState *bs); 543 void (*bdrv_io_unplug)(BlockDriverState *bs); 544 545 /** 546 * Try to get @bs's logical and physical block size. 547 * On success, store them in @bsz and return zero. 548 * On failure, return negative errno. 549 */ 550 int (*bdrv_probe_blocksizes)(BlockDriverState *bs, BlockSizes *bsz); 551 /** 552 * Try to get @bs's geometry (cyls, heads, sectors) 553 * On success, store them in @geo and return 0. 554 * On failure return -errno. 555 * Only drivers that want to override guest geometry implement this 556 * callback; see hd_geometry_guess(). 557 */ 558 int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo); 559 560 /** 561 * bdrv_co_drain_begin is called if implemented in the beginning of a 562 * drain operation to drain and stop any internal sources of requests in 563 * the driver. 564 * bdrv_co_drain_end is called if implemented at the end of the drain. 565 * 566 * They should be used by the driver to e.g. manage scheduled I/O 567 * requests, or toggle an internal state. After the end of the drain new 568 * requests will continue normally. 569 */ 570 void coroutine_fn (*bdrv_co_drain_begin)(BlockDriverState *bs); 571 void coroutine_fn (*bdrv_co_drain_end)(BlockDriverState *bs); 572 573 void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child, 574 Error **errp); 575 void (*bdrv_del_child)(BlockDriverState *parent, BdrvChild *child, 576 Error **errp); 577 578 /** 579 * Informs the block driver that a permission change is intended. The 580 * driver checks whether the change is permissible and may take other 581 * preparations for the change (e.g. get file system locks). This operation 582 * is always followed either by a call to either .bdrv_set_perm or 583 * .bdrv_abort_perm_update. 584 * 585 * Checks whether the requested set of cumulative permissions in @perm 586 * can be granted for accessing @bs and whether no other users are using 587 * permissions other than those given in @shared (both arguments take 588 * BLK_PERM_* bitmasks). 589 * 590 * If both conditions are met, 0 is returned. Otherwise, -errno is returned 591 * and errp is set to an error describing the conflict. 592 */ 593 int (*bdrv_check_perm)(BlockDriverState *bs, uint64_t perm, 594 uint64_t shared, Error **errp); 595 596 /** 597 * Called to inform the driver that the set of cumulative set of used 598 * permissions for @bs has changed to @perm, and the set of sharable 599 * permission to @shared. The driver can use this to propagate changes to 600 * its children (i.e. request permissions only if a parent actually needs 601 * them). 602 * 603 * This function is only invoked after bdrv_check_perm(), so block drivers 604 * may rely on preparations made in their .bdrv_check_perm implementation. 605 */ 606 void (*bdrv_set_perm)(BlockDriverState *bs, uint64_t perm, uint64_t shared); 607 608 /* 609 * Called to inform the driver that after a previous bdrv_check_perm() 610 * call, the permission update is not performed and any preparations made 611 * for it (e.g. taken file locks) need to be undone. 612 * 613 * This function can be called even for nodes that never saw a 614 * bdrv_check_perm() call. It is a no-op then. 615 */ 616 void (*bdrv_abort_perm_update)(BlockDriverState *bs); 617 618 /** 619 * Returns in @nperm and @nshared the permissions that the driver for @bs 620 * needs on its child @c, based on the cumulative permissions requested by 621 * the parents in @parent_perm and @parent_shared. 622 * 623 * If @c is NULL, return the permissions for attaching a new child for the 624 * given @child_class and @role. 625 * 626 * If @reopen_queue is non-NULL, don't return the currently needed 627 * permissions, but those that will be needed after applying the 628 * @reopen_queue. 629 */ 630 void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c, 631 BdrvChildRole role, 632 BlockReopenQueue *reopen_queue, 633 uint64_t parent_perm, uint64_t parent_shared, 634 uint64_t *nperm, uint64_t *nshared); 635 636 bool (*bdrv_supports_persistent_dirty_bitmap)(BlockDriverState *bs); 637 bool (*bdrv_co_can_store_new_dirty_bitmap)(BlockDriverState *bs, 638 const char *name, 639 uint32_t granularity, 640 Error **errp); 641 int (*bdrv_co_remove_persistent_dirty_bitmap)(BlockDriverState *bs, 642 const char *name, 643 Error **errp); 644 645 /** 646 * Register/unregister a buffer for I/O. For example, when the driver is 647 * interested to know the memory areas that will later be used in iovs, so 648 * that it can do IOMMU mapping with VFIO etc., in order to get better 649 * performance. In the case of VFIO drivers, this callback is used to do 650 * DMA mapping for hot buffers. 651 */ 652 void (*bdrv_register_buf)(BlockDriverState *bs, void *host, size_t size); 653 void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host); 654 QLIST_ENTRY(BlockDriver) list; 655 656 /* Pointer to a NULL-terminated array of names of strong options 657 * that can be specified for bdrv_open(). A strong option is one 658 * that changes the data of a BDS. 659 * If this pointer is NULL, the array is considered empty. 660 * "filename" and "driver" are always considered strong. */ 661 const char *const *strong_runtime_opts; 662 }; 663 664 static inline bool block_driver_can_compress(BlockDriver *drv) 665 { 666 return drv->bdrv_co_pwritev_compressed || 667 drv->bdrv_co_pwritev_compressed_part; 668 } 669 670 typedef struct BlockLimits { 671 /* Alignment requirement, in bytes, for offset/length of I/O 672 * requests. Must be a power of 2 less than INT_MAX; defaults to 673 * 1 for drivers with modern byte interfaces, and to 512 674 * otherwise. */ 675 uint32_t request_alignment; 676 677 /* 678 * Maximum number of bytes that can be discarded at once. Must be multiple 679 * of pdiscard_alignment, but need not be power of 2. May be 0 if no 680 * inherent 64-bit limit. 681 */ 682 int64_t max_pdiscard; 683 684 /* Optimal alignment for discard requests in bytes. A power of 2 685 * is best but not mandatory. Must be a multiple of 686 * bl.request_alignment, and must be less than max_pdiscard if 687 * that is set. May be 0 if bl.request_alignment is good enough */ 688 uint32_t pdiscard_alignment; 689 690 /* 691 * Maximum number of bytes that can zeroized at once. Must be multiple of 692 * pwrite_zeroes_alignment. 0 means no limit. 693 */ 694 int64_t max_pwrite_zeroes; 695 696 /* Optimal alignment for write zeroes requests in bytes. A power 697 * of 2 is best but not mandatory. Must be a multiple of 698 * bl.request_alignment, and must be less than max_pwrite_zeroes 699 * if that is set. May be 0 if bl.request_alignment is good 700 * enough */ 701 uint32_t pwrite_zeroes_alignment; 702 703 /* Optimal transfer length in bytes. A power of 2 is best but not 704 * mandatory. Must be a multiple of bl.request_alignment, or 0 if 705 * no preferred size */ 706 uint32_t opt_transfer; 707 708 /* Maximal transfer length in bytes. Need not be power of 2, but 709 * must be multiple of opt_transfer and bl.request_alignment, or 0 710 * for no 32-bit limit. For now, anything larger than INT_MAX is 711 * clamped down. */ 712 uint32_t max_transfer; 713 714 /* Maximal hardware transfer length in bytes. Applies whenever 715 * transfers to the device bypass the kernel I/O scheduler, for 716 * example with SG_IO. If larger than max_transfer or if zero, 717 * blk_get_max_hw_transfer will fall back to max_transfer. 718 */ 719 uint64_t max_hw_transfer; 720 721 /* Maximal number of scatter/gather elements allowed by the hardware. 722 * Applies whenever transfers to the device bypass the kernel I/O 723 * scheduler, for example with SG_IO. If larger than max_iov 724 * or if zero, blk_get_max_hw_iov will fall back to max_iov. 725 */ 726 int max_hw_iov; 727 728 /* memory alignment, in bytes so that no bounce buffer is needed */ 729 size_t min_mem_alignment; 730 731 /* memory alignment, in bytes, for bounce buffer */ 732 size_t opt_mem_alignment; 733 734 /* maximum number of iovec elements */ 735 int max_iov; 736 } BlockLimits; 737 738 typedef struct BdrvOpBlocker BdrvOpBlocker; 739 740 typedef struct BdrvAioNotifier { 741 void (*attached_aio_context)(AioContext *new_context, void *opaque); 742 void (*detach_aio_context)(void *opaque); 743 744 void *opaque; 745 bool deleted; 746 747 QLIST_ENTRY(BdrvAioNotifier) list; 748 } BdrvAioNotifier; 749 750 struct BdrvChildClass { 751 /* If true, bdrv_replace_node() doesn't change the node this BdrvChild 752 * points to. */ 753 bool stay_at_node; 754 755 /* If true, the parent is a BlockDriverState and bdrv_next_all_states() 756 * will return it. This information is used for drain_all, where every node 757 * will be drained separately, so the drain only needs to be propagated to 758 * non-BDS parents. */ 759 bool parent_is_bds; 760 761 void (*inherit_options)(BdrvChildRole role, bool parent_is_format, 762 int *child_flags, QDict *child_options, 763 int parent_flags, QDict *parent_options); 764 765 void (*change_media)(BdrvChild *child, bool load); 766 void (*resize)(BdrvChild *child); 767 768 /* Returns a name that is supposedly more useful for human users than the 769 * node name for identifying the node in question (in particular, a BB 770 * name), or NULL if the parent can't provide a better name. */ 771 const char *(*get_name)(BdrvChild *child); 772 773 /* Returns a malloced string that describes the parent of the child for a 774 * human reader. This could be a node-name, BlockBackend name, qdev ID or 775 * QOM path of the device owning the BlockBackend, job type and ID etc. The 776 * caller is responsible for freeing the memory. */ 777 char *(*get_parent_desc)(BdrvChild *child); 778 779 /* 780 * If this pair of functions is implemented, the parent doesn't issue new 781 * requests after returning from .drained_begin() until .drained_end() is 782 * called. 783 * 784 * These functions must not change the graph (and therefore also must not 785 * call aio_poll(), which could change the graph indirectly). 786 * 787 * If drained_end() schedules background operations, it must atomically 788 * increment *drained_end_counter for each such operation and atomically 789 * decrement it once the operation has settled. 790 * 791 * Note that this can be nested. If drained_begin() was called twice, new 792 * I/O is allowed only after drained_end() was called twice, too. 793 */ 794 void (*drained_begin)(BdrvChild *child); 795 void (*drained_end)(BdrvChild *child, int *drained_end_counter); 796 797 /* 798 * Returns whether the parent has pending requests for the child. This 799 * callback is polled after .drained_begin() has been called until all 800 * activity on the child has stopped. 801 */ 802 bool (*drained_poll)(BdrvChild *child); 803 804 /* Notifies the parent that the child has been activated/inactivated (e.g. 805 * when migration is completing) and it can start/stop requesting 806 * permissions and doing I/O on it. */ 807 void (*activate)(BdrvChild *child, Error **errp); 808 int (*inactivate)(BdrvChild *child); 809 810 void (*attach)(BdrvChild *child); 811 void (*detach)(BdrvChild *child); 812 813 /* Notifies the parent that the filename of its child has changed (e.g. 814 * because the direct child was removed from the backing chain), so that it 815 * can update its reference. */ 816 int (*update_filename)(BdrvChild *child, BlockDriverState *new_base, 817 const char *filename, Error **errp); 818 819 bool (*can_set_aio_ctx)(BdrvChild *child, AioContext *ctx, 820 GSList **ignore, Error **errp); 821 void (*set_aio_ctx)(BdrvChild *child, AioContext *ctx, GSList **ignore); 822 823 AioContext *(*get_parent_aio_context)(BdrvChild *child); 824 }; 825 826 extern const BdrvChildClass child_of_bds; 827 828 struct BdrvChild { 829 BlockDriverState *bs; 830 char *name; 831 const BdrvChildClass *klass; 832 BdrvChildRole role; 833 void *opaque; 834 835 /** 836 * Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask) 837 */ 838 uint64_t perm; 839 840 /** 841 * Permissions that can still be granted to other users of @bs while this 842 * BdrvChild is still attached to it. (BLK_PERM_* bitmask) 843 */ 844 uint64_t shared_perm; 845 846 /* 847 * This link is frozen: the child can neither be replaced nor 848 * detached from the parent. 849 */ 850 bool frozen; 851 852 /* 853 * How many times the parent of this child has been drained 854 * (through klass->drained_*). 855 * Usually, this is equal to bs->quiesce_counter (potentially 856 * reduced by bdrv_drain_all_count). It may differ while the 857 * child is entering or leaving a drained section. 858 */ 859 int parent_quiesce_counter; 860 861 QLIST_ENTRY(BdrvChild) next; 862 QLIST_ENTRY(BdrvChild) next_parent; 863 }; 864 865 /* 866 * Allows bdrv_co_block_status() to cache one data region for a 867 * protocol node. 868 * 869 * @valid: Whether the cache is valid (should be accessed with atomic 870 * functions so this can be reset by RCU readers) 871 * @data_start: Offset where we know (or strongly assume) is data 872 * @data_end: Offset where the data region ends (which is not necessarily 873 * the start of a zeroed region) 874 */ 875 typedef struct BdrvBlockStatusCache { 876 struct rcu_head rcu; 877 878 bool valid; 879 int64_t data_start; 880 int64_t data_end; 881 } BdrvBlockStatusCache; 882 883 struct BlockDriverState { 884 /* Protected by big QEMU lock or read-only after opening. No special 885 * locking needed during I/O... 886 */ 887 int open_flags; /* flags used to open the file, re-used for re-open */ 888 bool encrypted; /* if true, the media is encrypted */ 889 bool sg; /* if true, the device is a /dev/sg* */ 890 bool probed; /* if true, format was probed rather than specified */ 891 bool force_share; /* if true, always allow all shared permissions */ 892 bool implicit; /* if true, this filter node was automatically inserted */ 893 894 BlockDriver *drv; /* NULL means no media */ 895 void *opaque; 896 897 AioContext *aio_context; /* event loop used for fd handlers, timers, etc */ 898 /* long-running tasks intended to always use the same AioContext as this 899 * BDS may register themselves in this list to be notified of changes 900 * regarding this BDS's context */ 901 QLIST_HEAD(, BdrvAioNotifier) aio_notifiers; 902 bool walking_aio_notifiers; /* to make removal during iteration safe */ 903 904 char filename[PATH_MAX]; 905 /* 906 * If not empty, this image is a diff in relation to backing_file. 907 * Note that this is the name given in the image header and 908 * therefore may or may not be equal to .backing->bs->filename. 909 * If this field contains a relative path, it is to be resolved 910 * relatively to the overlay's location. 911 */ 912 char backing_file[PATH_MAX]; 913 /* 914 * The backing filename indicated by the image header. Contrary 915 * to backing_file, if we ever open this file, auto_backing_file 916 * is replaced by the resulting BDS's filename (i.e. after a 917 * bdrv_refresh_filename() run). 918 */ 919 char auto_backing_file[PATH_MAX]; 920 char backing_format[16]; /* if non-zero and backing_file exists */ 921 922 QDict *full_open_options; 923 char exact_filename[PATH_MAX]; 924 925 BdrvChild *backing; 926 BdrvChild *file; 927 928 /* I/O Limits */ 929 BlockLimits bl; 930 931 /* 932 * Flags honored during pread 933 */ 934 unsigned int supported_read_flags; 935 /* Flags honored during pwrite (so far: BDRV_REQ_FUA, 936 * BDRV_REQ_WRITE_UNCHANGED). 937 * If a driver does not support BDRV_REQ_WRITE_UNCHANGED, those 938 * writes will be issued as normal writes without the flag set. 939 * This is important to note for drivers that do not explicitly 940 * request a WRITE permission for their children and instead take 941 * the same permissions as their parent did (this is commonly what 942 * block filters do). Such drivers have to be aware that the 943 * parent may have taken a WRITE_UNCHANGED permission only and is 944 * issuing such requests. Drivers either must make sure that 945 * these requests do not result in plain WRITE accesses (usually 946 * by supporting BDRV_REQ_WRITE_UNCHANGED, and then forwarding 947 * every incoming write request as-is, including potentially that 948 * flag), or they have to explicitly take the WRITE permission for 949 * their children. */ 950 unsigned int supported_write_flags; 951 /* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA, 952 * BDRV_REQ_MAY_UNMAP, BDRV_REQ_WRITE_UNCHANGED) */ 953 unsigned int supported_zero_flags; 954 /* 955 * Flags honoured during truncate (so far: BDRV_REQ_ZERO_WRITE). 956 * 957 * If BDRV_REQ_ZERO_WRITE is given, the truncate operation must make sure 958 * that any added space reads as all zeros. If this can't be guaranteed, 959 * the operation must fail. 960 */ 961 unsigned int supported_truncate_flags; 962 963 /* the following member gives a name to every node on the bs graph. */ 964 char node_name[32]; 965 /* element of the list of named nodes building the graph */ 966 QTAILQ_ENTRY(BlockDriverState) node_list; 967 /* element of the list of all BlockDriverStates (all_bdrv_states) */ 968 QTAILQ_ENTRY(BlockDriverState) bs_list; 969 /* element of the list of monitor-owned BDS */ 970 QTAILQ_ENTRY(BlockDriverState) monitor_list; 971 int refcnt; 972 973 /* operation blockers */ 974 QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; 975 976 /* The node that this node inherited default options from (and a reopen on 977 * which can affect this node by changing these defaults). This is always a 978 * parent node of this node. */ 979 BlockDriverState *inherits_from; 980 QLIST_HEAD(, BdrvChild) children; 981 QLIST_HEAD(, BdrvChild) parents; 982 983 QDict *options; 984 QDict *explicit_options; 985 BlockdevDetectZeroesOptions detect_zeroes; 986 987 /* The error object in use for blocking operations on backing_hd */ 988 Error *backing_blocker; 989 990 /* Protected by AioContext lock */ 991 992 /* If we are reading a disk image, give its size in sectors. 993 * Generally read-only; it is written to by load_snapshot and 994 * save_snaphost, but the block layer is quiescent during those. 995 */ 996 int64_t total_sectors; 997 998 /* threshold limit for writes, in bytes. "High water mark". */ 999 uint64_t write_threshold_offset; 1000 1001 /* Writing to the list requires the BQL _and_ the dirty_bitmap_mutex. 1002 * Reading from the list can be done with either the BQL or the 1003 * dirty_bitmap_mutex. Modifying a bitmap only requires 1004 * dirty_bitmap_mutex. */ 1005 QemuMutex dirty_bitmap_mutex; 1006 QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps; 1007 1008 /* Offset after the highest byte written to */ 1009 Stat64 wr_highest_offset; 1010 1011 /* If true, copy read backing sectors into image. Can be >1 if more 1012 * than one client has requested copy-on-read. Accessed with atomic 1013 * ops. 1014 */ 1015 int copy_on_read; 1016 1017 /* number of in-flight requests; overall and serialising. 1018 * Accessed with atomic ops. 1019 */ 1020 unsigned int in_flight; 1021 unsigned int serialising_in_flight; 1022 1023 /* counter for nested bdrv_io_plug. 1024 * Accessed with atomic ops. 1025 */ 1026 unsigned io_plugged; 1027 1028 /* do we need to tell the quest if we have a volatile write cache? */ 1029 int enable_write_cache; 1030 1031 /* Accessed with atomic ops. */ 1032 int quiesce_counter; 1033 int recursive_quiesce_counter; 1034 1035 unsigned int write_gen; /* Current data generation */ 1036 1037 /* Protected by reqs_lock. */ 1038 CoMutex reqs_lock; 1039 QLIST_HEAD(, BdrvTrackedRequest) tracked_requests; 1040 CoQueue flush_queue; /* Serializing flush queue */ 1041 bool active_flush_req; /* Flush request in flight? */ 1042 1043 /* Only read/written by whoever has set active_flush_req to true. */ 1044 unsigned int flushed_gen; /* Flushed write generation */ 1045 1046 /* BdrvChild links to this node may never be frozen */ 1047 bool never_freeze; 1048 1049 /* Lock for block-status cache RCU writers */ 1050 CoMutex bsc_modify_lock; 1051 /* Always non-NULL, but must only be dereferenced under an RCU read guard */ 1052 BdrvBlockStatusCache *block_status_cache; 1053 }; 1054 1055 struct BlockBackendRootState { 1056 int open_flags; 1057 BlockdevDetectZeroesOptions detect_zeroes; 1058 }; 1059 1060 typedef enum BlockMirrorBackingMode { 1061 /* Reuse the existing backing chain from the source for the target. 1062 * - sync=full: Set backing BDS to NULL. 1063 * - sync=top: Use source's backing BDS. 1064 * - sync=none: Use source as the backing BDS. */ 1065 MIRROR_SOURCE_BACKING_CHAIN, 1066 1067 /* Open the target's backing chain completely anew */ 1068 MIRROR_OPEN_BACKING_CHAIN, 1069 1070 /* Do not change the target's backing BDS after job completion */ 1071 MIRROR_LEAVE_BACKING_CHAIN, 1072 } BlockMirrorBackingMode; 1073 1074 1075 /* Essential block drivers which must always be statically linked into qemu, and 1076 * which therefore can be accessed without using bdrv_find_format() */ 1077 extern BlockDriver bdrv_file; 1078 extern BlockDriver bdrv_raw; 1079 extern BlockDriver bdrv_qcow2; 1080 1081 int coroutine_fn bdrv_co_preadv(BdrvChild *child, 1082 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 1083 BdrvRequestFlags flags); 1084 int coroutine_fn bdrv_co_preadv_part(BdrvChild *child, 1085 int64_t offset, int64_t bytes, 1086 QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags); 1087 int coroutine_fn bdrv_co_pwritev(BdrvChild *child, 1088 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 1089 BdrvRequestFlags flags); 1090 int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child, 1091 int64_t offset, int64_t bytes, 1092 QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags); 1093 1094 static inline int coroutine_fn bdrv_co_pread(BdrvChild *child, 1095 int64_t offset, unsigned int bytes, void *buf, BdrvRequestFlags flags) 1096 { 1097 QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); 1098 1099 return bdrv_co_preadv(child, offset, bytes, &qiov, flags); 1100 } 1101 1102 static inline int coroutine_fn bdrv_co_pwrite(BdrvChild *child, 1103 int64_t offset, unsigned int bytes, void *buf, BdrvRequestFlags flags) 1104 { 1105 QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); 1106 1107 return bdrv_co_pwritev(child, offset, bytes, &qiov, flags); 1108 } 1109 1110 extern unsigned int bdrv_drain_all_count; 1111 void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent); 1112 void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent); 1113 1114 bool coroutine_fn bdrv_make_request_serialising(BdrvTrackedRequest *req, 1115 uint64_t align); 1116 BdrvTrackedRequest *coroutine_fn bdrv_co_get_self_request(BlockDriverState *bs); 1117 1118 int get_tmp_filename(char *filename, int size); 1119 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size, 1120 const char *filename); 1121 1122 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, 1123 QDict *options); 1124 1125 /** 1126 * bdrv_add_aio_context_notifier: 1127 * 1128 * If a long-running job intends to be always run in the same AioContext as a 1129 * certain BDS, it may use this function to be notified of changes regarding the 1130 * association of the BDS to an AioContext. 1131 * 1132 * attached_aio_context() is called after the target BDS has been attached to a 1133 * new AioContext; detach_aio_context() is called before the target BDS is being 1134 * detached from its old AioContext. 1135 */ 1136 void bdrv_add_aio_context_notifier(BlockDriverState *bs, 1137 void (*attached_aio_context)(AioContext *new_context, void *opaque), 1138 void (*detach_aio_context)(void *opaque), void *opaque); 1139 1140 /** 1141 * bdrv_remove_aio_context_notifier: 1142 * 1143 * Unsubscribe of change notifications regarding the BDS's AioContext. The 1144 * parameters given here have to be the same as those given to 1145 * bdrv_add_aio_context_notifier(). 1146 */ 1147 void bdrv_remove_aio_context_notifier(BlockDriverState *bs, 1148 void (*aio_context_attached)(AioContext *, 1149 void *), 1150 void (*aio_context_detached)(void *), 1151 void *opaque); 1152 1153 /** 1154 * bdrv_wakeup: 1155 * @bs: The BlockDriverState for which an I/O operation has been completed. 1156 * 1157 * Wake up the main thread if it is waiting on BDRV_POLL_WHILE. During 1158 * synchronous I/O on a BlockDriverState that is attached to another 1159 * I/O thread, the main thread lets the I/O thread's event loop run, 1160 * waiting for the I/O operation to complete. A bdrv_wakeup will wake 1161 * up the main thread if necessary. 1162 * 1163 * Manual calls to bdrv_wakeup are rarely necessary, because 1164 * bdrv_dec_in_flight already calls it. 1165 */ 1166 void bdrv_wakeup(BlockDriverState *bs); 1167 1168 #ifdef _WIN32 1169 int is_windows_drive(const char *filename); 1170 #endif 1171 1172 /** 1173 * stream_start: 1174 * @job_id: The id of the newly-created job, or %NULL to use the 1175 * device name of @bs. 1176 * @bs: Block device to operate on. 1177 * @base: Block device that will become the new base, or %NULL to 1178 * flatten the whole backing file chain onto @bs. 1179 * @backing_file_str: The file name that will be written to @bs as the 1180 * the new backing file if the job completes. Ignored if @base is %NULL. 1181 * @creation_flags: Flags that control the behavior of the Job lifetime. 1182 * See @BlockJobCreateFlags 1183 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 1184 * @on_error: The action to take upon error. 1185 * @filter_node_name: The node name that should be assigned to the filter 1186 * driver that the stream job inserts into the graph above 1187 * @bs. NULL means that a node name should be autogenerated. 1188 * @errp: Error object. 1189 * 1190 * Start a streaming operation on @bs. Clusters that are unallocated 1191 * in @bs, but allocated in any image between @base and @bs (both 1192 * exclusive) will be written to @bs. At the end of a successful 1193 * streaming job, the backing file of @bs will be changed to 1194 * @backing_file_str in the written image and to @base in the live 1195 * BlockDriverState. 1196 */ 1197 void stream_start(const char *job_id, BlockDriverState *bs, 1198 BlockDriverState *base, const char *backing_file_str, 1199 BlockDriverState *bottom, 1200 int creation_flags, int64_t speed, 1201 BlockdevOnError on_error, 1202 const char *filter_node_name, 1203 Error **errp); 1204 1205 /** 1206 * commit_start: 1207 * @job_id: The id of the newly-created job, or %NULL to use the 1208 * device name of @bs. 1209 * @bs: Active block device. 1210 * @top: Top block device to be committed. 1211 * @base: Block device that will be written into, and become the new top. 1212 * @creation_flags: Flags that control the behavior of the Job lifetime. 1213 * See @BlockJobCreateFlags 1214 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 1215 * @on_error: The action to take upon error. 1216 * @backing_file_str: String to use as the backing file in @top's overlay 1217 * @filter_node_name: The node name that should be assigned to the filter 1218 * driver that the commit job inserts into the graph above @top. NULL means 1219 * that a node name should be autogenerated. 1220 * @errp: Error object. 1221 * 1222 */ 1223 void commit_start(const char *job_id, BlockDriverState *bs, 1224 BlockDriverState *base, BlockDriverState *top, 1225 int creation_flags, int64_t speed, 1226 BlockdevOnError on_error, const char *backing_file_str, 1227 const char *filter_node_name, Error **errp); 1228 /** 1229 * commit_active_start: 1230 * @job_id: The id of the newly-created job, or %NULL to use the 1231 * device name of @bs. 1232 * @bs: Active block device to be committed. 1233 * @base: Block device that will be written into, and become the new top. 1234 * @creation_flags: Flags that control the behavior of the Job lifetime. 1235 * See @BlockJobCreateFlags 1236 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 1237 * @on_error: The action to take upon error. 1238 * @filter_node_name: The node name that should be assigned to the filter 1239 * driver that the commit job inserts into the graph above @bs. NULL means that 1240 * a node name should be autogenerated. 1241 * @cb: Completion function for the job. 1242 * @opaque: Opaque pointer value passed to @cb. 1243 * @auto_complete: Auto complete the job. 1244 * @errp: Error object. 1245 * 1246 */ 1247 BlockJob *commit_active_start(const char *job_id, BlockDriverState *bs, 1248 BlockDriverState *base, int creation_flags, 1249 int64_t speed, BlockdevOnError on_error, 1250 const char *filter_node_name, 1251 BlockCompletionFunc *cb, void *opaque, 1252 bool auto_complete, Error **errp); 1253 /* 1254 * mirror_start: 1255 * @job_id: The id of the newly-created job, or %NULL to use the 1256 * device name of @bs. 1257 * @bs: Block device to operate on. 1258 * @target: Block device to write to. 1259 * @replaces: Block graph node name to replace once the mirror is done. Can 1260 * only be used when full mirroring is selected. 1261 * @creation_flags: Flags that control the behavior of the Job lifetime. 1262 * See @BlockJobCreateFlags 1263 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 1264 * @granularity: The chosen granularity for the dirty bitmap. 1265 * @buf_size: The amount of data that can be in flight at one time. 1266 * @mode: Whether to collapse all images in the chain to the target. 1267 * @backing_mode: How to establish the target's backing chain after completion. 1268 * @zero_target: Whether the target should be explicitly zero-initialized 1269 * @on_source_error: The action to take upon error reading from the source. 1270 * @on_target_error: The action to take upon error writing to the target. 1271 * @unmap: Whether to unmap target where source sectors only contain zeroes. 1272 * @filter_node_name: The node name that should be assigned to the filter 1273 * driver that the mirror job inserts into the graph above @bs. NULL means that 1274 * a node name should be autogenerated. 1275 * @copy_mode: When to trigger writes to the target. 1276 * @errp: Error object. 1277 * 1278 * Start a mirroring operation on @bs. Clusters that are allocated 1279 * in @bs will be written to @target until the job is cancelled or 1280 * manually completed. At the end of a successful mirroring job, 1281 * @bs will be switched to read from @target. 1282 */ 1283 void mirror_start(const char *job_id, BlockDriverState *bs, 1284 BlockDriverState *target, const char *replaces, 1285 int creation_flags, int64_t speed, 1286 uint32_t granularity, int64_t buf_size, 1287 MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, 1288 bool zero_target, 1289 BlockdevOnError on_source_error, 1290 BlockdevOnError on_target_error, 1291 bool unmap, const char *filter_node_name, 1292 MirrorCopyMode copy_mode, Error **errp); 1293 1294 /* 1295 * backup_job_create: 1296 * @job_id: The id of the newly-created job, or %NULL to use the 1297 * device name of @bs. 1298 * @bs: Block device to operate on. 1299 * @target: Block device to write to. 1300 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 1301 * @sync_mode: What parts of the disk image should be copied to the destination. 1302 * @sync_bitmap: The dirty bitmap if sync_mode is 'bitmap' or 'incremental' 1303 * @bitmap_mode: The bitmap synchronization policy to use. 1304 * @perf: Performance options. All actual fields assumed to be present, 1305 * all ".has_*" fields are ignored. 1306 * @on_source_error: The action to take upon error reading from the source. 1307 * @on_target_error: The action to take upon error writing to the target. 1308 * @creation_flags: Flags that control the behavior of the Job lifetime. 1309 * See @BlockJobCreateFlags 1310 * @cb: Completion function for the job. 1311 * @opaque: Opaque pointer value passed to @cb. 1312 * @txn: Transaction that this job is part of (may be NULL). 1313 * 1314 * Create a backup operation on @bs. Clusters in @bs are written to @target 1315 * until the job is cancelled or manually completed. 1316 */ 1317 BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, 1318 BlockDriverState *target, int64_t speed, 1319 MirrorSyncMode sync_mode, 1320 BdrvDirtyBitmap *sync_bitmap, 1321 BitmapSyncMode bitmap_mode, 1322 bool compress, 1323 const char *filter_node_name, 1324 BackupPerf *perf, 1325 BlockdevOnError on_source_error, 1326 BlockdevOnError on_target_error, 1327 int creation_flags, 1328 BlockCompletionFunc *cb, void *opaque, 1329 JobTxn *txn, Error **errp); 1330 1331 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, 1332 const char *child_name, 1333 const BdrvChildClass *child_class, 1334 BdrvChildRole child_role, 1335 uint64_t perm, uint64_t shared_perm, 1336 void *opaque, Error **errp); 1337 void bdrv_root_unref_child(BdrvChild *child); 1338 1339 void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm, 1340 uint64_t *shared_perm); 1341 1342 /** 1343 * Sets a BdrvChild's permissions. Avoid if the parent is a BDS; use 1344 * bdrv_child_refresh_perms() instead and make the parent's 1345 * .bdrv_child_perm() implementation return the correct values. 1346 */ 1347 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, 1348 Error **errp); 1349 1350 /** 1351 * Calls bs->drv->bdrv_child_perm() and updates the child's permission 1352 * masks with the result. 1353 * Drivers should invoke this function whenever an event occurs that 1354 * makes their .bdrv_child_perm() implementation return different 1355 * values than before, but which will not result in the block layer 1356 * automatically refreshing the permissions. 1357 */ 1358 int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp); 1359 1360 bool bdrv_recurse_can_replace(BlockDriverState *bs, 1361 BlockDriverState *to_replace); 1362 1363 /* 1364 * Default implementation for BlockDriver.bdrv_child_perm() that can 1365 * be used by block filters and image formats, as long as they use the 1366 * child_of_bds child class and set an appropriate BdrvChildRole. 1367 */ 1368 void bdrv_default_perms(BlockDriverState *bs, BdrvChild *c, 1369 BdrvChildRole role, BlockReopenQueue *reopen_queue, 1370 uint64_t perm, uint64_t shared, 1371 uint64_t *nperm, uint64_t *nshared); 1372 1373 const char *bdrv_get_parent_name(const BlockDriverState *bs); 1374 void blk_dev_change_media_cb(BlockBackend *blk, bool load, Error **errp); 1375 bool blk_dev_has_removable_media(BlockBackend *blk); 1376 bool blk_dev_has_tray(BlockBackend *blk); 1377 void blk_dev_eject_request(BlockBackend *blk, bool force); 1378 bool blk_dev_is_tray_open(BlockBackend *blk); 1379 bool blk_dev_is_medium_locked(BlockBackend *blk); 1380 1381 void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes); 1382 1383 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out); 1384 void bdrv_restore_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *backup); 1385 bool bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest, 1386 const BdrvDirtyBitmap *src, 1387 HBitmap **backup, bool lock); 1388 1389 void bdrv_inc_in_flight(BlockDriverState *bs); 1390 void bdrv_dec_in_flight(BlockDriverState *bs); 1391 1392 void blockdev_close_all_bdrv_states(void); 1393 1394 int coroutine_fn bdrv_co_copy_range_from(BdrvChild *src, int64_t src_offset, 1395 BdrvChild *dst, int64_t dst_offset, 1396 int64_t bytes, 1397 BdrvRequestFlags read_flags, 1398 BdrvRequestFlags write_flags); 1399 int coroutine_fn bdrv_co_copy_range_to(BdrvChild *src, int64_t src_offset, 1400 BdrvChild *dst, int64_t dst_offset, 1401 int64_t bytes, 1402 BdrvRequestFlags read_flags, 1403 BdrvRequestFlags write_flags); 1404 1405 int refresh_total_sectors(BlockDriverState *bs, int64_t hint); 1406 1407 void bdrv_set_monitor_owned(BlockDriverState *bs); 1408 BlockDriverState *bds_tree_init(QDict *bs_opts, Error **errp); 1409 1410 /** 1411 * Simple implementation of bdrv_co_create_opts for protocol drivers 1412 * which only support creation via opening a file 1413 * (usually existing raw storage device) 1414 */ 1415 int coroutine_fn bdrv_co_create_opts_simple(BlockDriver *drv, 1416 const char *filename, 1417 QemuOpts *opts, 1418 Error **errp); 1419 extern QemuOptsList bdrv_create_opts_simple; 1420 1421 BdrvDirtyBitmap *block_dirty_bitmap_lookup(const char *node, 1422 const char *name, 1423 BlockDriverState **pbs, 1424 Error **errp); 1425 BdrvDirtyBitmap *block_dirty_bitmap_merge(const char *node, const char *target, 1426 BlockDirtyBitmapMergeSourceList *bms, 1427 HBitmap **backup, Error **errp); 1428 BdrvDirtyBitmap *block_dirty_bitmap_remove(const char *node, const char *name, 1429 bool release, 1430 BlockDriverState **bitmap_bs, 1431 Error **errp); 1432 1433 BdrvChild *bdrv_cow_child(BlockDriverState *bs); 1434 BdrvChild *bdrv_filter_child(BlockDriverState *bs); 1435 BdrvChild *bdrv_filter_or_cow_child(BlockDriverState *bs); 1436 BdrvChild *bdrv_primary_child(BlockDriverState *bs); 1437 BlockDriverState *bdrv_skip_implicit_filters(BlockDriverState *bs); 1438 BlockDriverState *bdrv_skip_filters(BlockDriverState *bs); 1439 BlockDriverState *bdrv_backing_chain_next(BlockDriverState *bs); 1440 1441 static inline BlockDriverState *child_bs(BdrvChild *child) 1442 { 1443 return child ? child->bs : NULL; 1444 } 1445 1446 static inline BlockDriverState *bdrv_cow_bs(BlockDriverState *bs) 1447 { 1448 return child_bs(bdrv_cow_child(bs)); 1449 } 1450 1451 static inline BlockDriverState *bdrv_filter_bs(BlockDriverState *bs) 1452 { 1453 return child_bs(bdrv_filter_child(bs)); 1454 } 1455 1456 static inline BlockDriverState *bdrv_filter_or_cow_bs(BlockDriverState *bs) 1457 { 1458 return child_bs(bdrv_filter_or_cow_child(bs)); 1459 } 1460 1461 static inline BlockDriverState *bdrv_primary_bs(BlockDriverState *bs) 1462 { 1463 return child_bs(bdrv_primary_child(bs)); 1464 } 1465 1466 /** 1467 * End all quiescent sections started by bdrv_drain_all_begin(). This is 1468 * needed when deleting a BDS before bdrv_drain_all_end() is called. 1469 * 1470 * NOTE: this is an internal helper for bdrv_close() *only*. No one else 1471 * should call it. 1472 */ 1473 void bdrv_drain_all_end_quiesce(BlockDriverState *bs); 1474 1475 /** 1476 * Check whether the given offset is in the cached block-status data 1477 * region. 1478 * 1479 * If it is, and @pnum is not NULL, *pnum is set to 1480 * `bsc.data_end - offset`, i.e. how many bytes, starting from 1481 * @offset, are data (according to the cache). 1482 * Otherwise, *pnum is not touched. 1483 */ 1484 bool bdrv_bsc_is_data(BlockDriverState *bs, int64_t offset, int64_t *pnum); 1485 1486 /** 1487 * If [offset, offset + bytes) overlaps with the currently cached 1488 * block-status region, invalidate the cache. 1489 * 1490 * (To be used by I/O paths that cause data regions to be zero or 1491 * holes.) 1492 */ 1493 void bdrv_bsc_invalidate_range(BlockDriverState *bs, 1494 int64_t offset, int64_t bytes); 1495 1496 /** 1497 * Mark the range [offset, offset + bytes) as a data region. 1498 */ 1499 void bdrv_bsc_fill(BlockDriverState *bs, int64_t offset, int64_t bytes); 1500 1501 #endif /* BLOCK_INT_H */ 1502