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 /* 129 * This function is invoked under BQL before .bdrv_co_amend() 130 * (which in contrast does not necessarily run under the BQL) 131 * to allow driver-specific initialization code that requires 132 * the BQL, like setting up specific permission flags. 133 */ 134 int (*bdrv_amend_pre_run)(BlockDriverState *bs, Error **errp); 135 /* 136 * This function is invoked under BQL after .bdrv_co_amend() 137 * to allow cleaning up what was done in .bdrv_amend_pre_run(). 138 */ 139 void (*bdrv_amend_clean)(BlockDriverState *bs); 140 141 /* 142 * Return true if @to_replace can be replaced by a BDS with the 143 * same data as @bs without it affecting @bs's behavior (that is, 144 * without it being visible to @bs's parents). 145 */ 146 bool (*bdrv_recurse_can_replace)(BlockDriverState *bs, 147 BlockDriverState *to_replace); 148 149 int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename); 150 int (*bdrv_probe_device)(const char *filename); 151 152 /* Any driver implementing this callback is expected to be able to handle 153 * NULL file names in its .bdrv_open() implementation */ 154 void (*bdrv_parse_filename)(const char *filename, QDict *options, Error **errp); 155 /* Drivers not implementing bdrv_parse_filename nor bdrv_open should have 156 * this field set to true, except ones that are defined only by their 157 * child's bs. 158 * An example of the last type will be the quorum block driver. 159 */ 160 bool bdrv_needs_filename; 161 162 /* 163 * Set if a driver can support backing files. This also implies the 164 * following semantics: 165 * 166 * - Return status 0 of .bdrv_co_block_status means that corresponding 167 * blocks are not allocated in this layer of backing-chain 168 * - For such (unallocated) blocks, read will: 169 * - fill buffer with zeros if there is no backing file 170 * - read from the backing file otherwise, where the block layer 171 * takes care of reading zeros beyond EOF if backing file is short 172 */ 173 bool supports_backing; 174 175 /* For handling image reopen for split or non-split files */ 176 int (*bdrv_reopen_prepare)(BDRVReopenState *reopen_state, 177 BlockReopenQueue *queue, Error **errp); 178 void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state); 179 void (*bdrv_reopen_commit_post)(BDRVReopenState *reopen_state); 180 void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state); 181 void (*bdrv_join_options)(QDict *options, QDict *old_options); 182 183 int (*bdrv_open)(BlockDriverState *bs, QDict *options, int flags, 184 Error **errp); 185 186 /* Protocol drivers should implement this instead of bdrv_open */ 187 int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags, 188 Error **errp); 189 void (*bdrv_close)(BlockDriverState *bs); 190 191 192 int coroutine_fn (*bdrv_co_create)(BlockdevCreateOptions *opts, 193 Error **errp); 194 int coroutine_fn (*bdrv_co_create_opts)(BlockDriver *drv, 195 const char *filename, 196 QemuOpts *opts, 197 Error **errp); 198 199 int coroutine_fn (*bdrv_co_amend)(BlockDriverState *bs, 200 BlockdevAmendOptions *opts, 201 bool force, 202 Error **errp); 203 204 int (*bdrv_amend_options)(BlockDriverState *bs, 205 QemuOpts *opts, 206 BlockDriverAmendStatusCB *status_cb, 207 void *cb_opaque, 208 bool force, 209 Error **errp); 210 211 int (*bdrv_make_empty)(BlockDriverState *bs); 212 213 /* 214 * Refreshes the bs->exact_filename field. If that is impossible, 215 * bs->exact_filename has to be left empty. 216 */ 217 void (*bdrv_refresh_filename)(BlockDriverState *bs); 218 219 /* 220 * Gathers the open options for all children into @target. 221 * A simple format driver (without backing file support) might 222 * implement this function like this: 223 * 224 * QINCREF(bs->file->bs->full_open_options); 225 * qdict_put(target, "file", bs->file->bs->full_open_options); 226 * 227 * If not specified, the generic implementation will simply put 228 * all children's options under their respective name. 229 * 230 * @backing_overridden is true when bs->backing seems not to be 231 * the child that would result from opening bs->backing_file. 232 * Therefore, if it is true, the backing child's options should be 233 * gathered; otherwise, there is no need since the backing child 234 * is the one implied by the image header. 235 * 236 * Note that ideally this function would not be needed. Every 237 * block driver which implements it is probably doing something 238 * shady regarding its runtime option structure. 239 */ 240 void (*bdrv_gather_child_options)(BlockDriverState *bs, QDict *target, 241 bool backing_overridden); 242 243 /* 244 * Returns an allocated string which is the directory name of this BDS: It 245 * will be used to make relative filenames absolute by prepending this 246 * function's return value to them. 247 */ 248 char *(*bdrv_dirname)(BlockDriverState *bs, Error **errp); 249 250 /* aio */ 251 BlockAIOCB *(*bdrv_aio_preadv)(BlockDriverState *bs, 252 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 253 BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); 254 BlockAIOCB *(*bdrv_aio_pwritev)(BlockDriverState *bs, 255 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 256 BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); 257 BlockAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs, 258 BlockCompletionFunc *cb, void *opaque); 259 BlockAIOCB *(*bdrv_aio_pdiscard)(BlockDriverState *bs, 260 int64_t offset, int bytes, 261 BlockCompletionFunc *cb, void *opaque); 262 263 int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs, 264 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); 265 266 /** 267 * @offset: position in bytes to read at 268 * @bytes: number of bytes to read 269 * @qiov: the buffers to fill with read data 270 * @flags: currently unused, always 0 271 * 272 * @offset and @bytes will be a multiple of 'request_alignment', 273 * but the length of individual @qiov elements does not have to 274 * be a multiple. 275 * 276 * @bytes will always equal the total size of @qiov, and will be 277 * no larger than 'max_transfer'. 278 * 279 * The buffer in @qiov may point directly to guest memory. 280 */ 281 int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs, 282 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 283 BdrvRequestFlags flags); 284 int coroutine_fn (*bdrv_co_preadv_part)(BlockDriverState *bs, 285 int64_t offset, int64_t bytes, 286 QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags); 287 int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs, 288 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int flags); 289 /** 290 * @offset: position in bytes to write at 291 * @bytes: number of bytes to write 292 * @qiov: the buffers containing data to write 293 * @flags: zero or more bits allowed by 'supported_write_flags' 294 * 295 * @offset and @bytes will be a multiple of 'request_alignment', 296 * but the length of individual @qiov elements does not have to 297 * be a multiple. 298 * 299 * @bytes will always equal the total size of @qiov, and will be 300 * no larger than 'max_transfer'. 301 * 302 * The buffer in @qiov may point directly to guest memory. 303 */ 304 int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs, 305 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 306 BdrvRequestFlags flags); 307 int coroutine_fn (*bdrv_co_pwritev_part)(BlockDriverState *bs, 308 int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset, 309 BdrvRequestFlags flags); 310 311 /* 312 * Efficiently zero a region of the disk image. Typically an image format 313 * would use a compact metadata representation to implement this. This 314 * function pointer may be NULL or return -ENOSUP and .bdrv_co_writev() 315 * will be called instead. 316 */ 317 int coroutine_fn (*bdrv_co_pwrite_zeroes)(BlockDriverState *bs, 318 int64_t offset, int64_t bytes, BdrvRequestFlags flags); 319 int coroutine_fn (*bdrv_co_pdiscard)(BlockDriverState *bs, 320 int64_t offset, int64_t bytes); 321 322 /* Map [offset, offset + nbytes) range onto a child of @bs to copy from, 323 * and invoke bdrv_co_copy_range_from(child, ...), or invoke 324 * bdrv_co_copy_range_to() if @bs is the leaf child to copy data from. 325 * 326 * See the comment of bdrv_co_copy_range for the parameter and return value 327 * semantics. 328 */ 329 int coroutine_fn (*bdrv_co_copy_range_from)(BlockDriverState *bs, 330 BdrvChild *src, 331 int64_t offset, 332 BdrvChild *dst, 333 int64_t dst_offset, 334 int64_t bytes, 335 BdrvRequestFlags read_flags, 336 BdrvRequestFlags write_flags); 337 338 /* Map [offset, offset + nbytes) range onto a child of bs to copy data to, 339 * and invoke bdrv_co_copy_range_to(child, src, ...), or perform the copy 340 * operation if @bs is the leaf and @src has the same BlockDriver. Return 341 * -ENOTSUP if @bs is the leaf but @src has a different BlockDriver. 342 * 343 * See the comment of bdrv_co_copy_range for the parameter and return value 344 * semantics. 345 */ 346 int coroutine_fn (*bdrv_co_copy_range_to)(BlockDriverState *bs, 347 BdrvChild *src, 348 int64_t src_offset, 349 BdrvChild *dst, 350 int64_t dst_offset, 351 int64_t bytes, 352 BdrvRequestFlags read_flags, 353 BdrvRequestFlags write_flags); 354 355 /* 356 * Building block for bdrv_block_status[_above] and 357 * bdrv_is_allocated[_above]. The driver should answer only 358 * according to the current layer, and should only need to set 359 * BDRV_BLOCK_DATA, BDRV_BLOCK_ZERO, BDRV_BLOCK_OFFSET_VALID, 360 * and/or BDRV_BLOCK_RAW; if the current layer defers to a backing 361 * layer, the result should be 0 (and not BDRV_BLOCK_ZERO). See 362 * block.h for the overall meaning of the bits. As a hint, the 363 * flag want_zero is true if the caller cares more about precise 364 * mappings (favor accurate _OFFSET_VALID/_ZERO) or false for 365 * overall allocation (favor larger *pnum, perhaps by reporting 366 * _DATA instead of _ZERO). The block layer guarantees input 367 * clamped to bdrv_getlength() and aligned to request_alignment, 368 * as well as non-NULL pnum, map, and file; in turn, the driver 369 * must return an error or set pnum to an aligned non-zero value. 370 * 371 * Note that @bytes is just a hint on how big of a region the 372 * caller wants to inspect. It is not a limit on *pnum. 373 * Implementations are free to return larger values of *pnum if 374 * doing so does not incur a performance penalty. 375 * 376 * block/io.c's bdrv_co_block_status() will utilize an unclamped 377 * *pnum value for the block-status cache on protocol nodes, prior 378 * to clamping *pnum for return to its caller. 379 */ 380 int coroutine_fn (*bdrv_co_block_status)(BlockDriverState *bs, 381 bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum, 382 int64_t *map, BlockDriverState **file); 383 384 /* 385 * This informs the driver that we are no longer interested in the result 386 * of in-flight requests, so don't waste the time if possible. 387 * 388 * One example usage is to avoid waiting for an nbd target node reconnect 389 * timeout during job-cancel with force=true. 390 */ 391 void (*bdrv_cancel_in_flight)(BlockDriverState *bs); 392 393 /* 394 * Invalidate any cached meta-data. 395 */ 396 void coroutine_fn (*bdrv_co_invalidate_cache)(BlockDriverState *bs, 397 Error **errp); 398 int (*bdrv_inactivate)(BlockDriverState *bs); 399 400 /* 401 * Flushes all data for all layers by calling bdrv_co_flush for underlying 402 * layers, if needed. This function is needed for deterministic 403 * synchronization of the flush finishing callback. 404 */ 405 int coroutine_fn (*bdrv_co_flush)(BlockDriverState *bs); 406 407 /* Delete a created file. */ 408 int coroutine_fn (*bdrv_co_delete_file)(BlockDriverState *bs, 409 Error **errp); 410 411 /* 412 * Flushes all data that was already written to the OS all the way down to 413 * the disk (for example file-posix.c calls fsync()). 414 */ 415 int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs); 416 417 /* 418 * Flushes all internal caches to the OS. The data may still sit in a 419 * writeback cache of the host OS, but it will survive a crash of the qemu 420 * process. 421 */ 422 int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs); 423 424 /* 425 * Drivers setting this field must be able to work with just a plain 426 * filename with '<protocol_name>:' as a prefix, and no other options. 427 * Options may be extracted from the filename by implementing 428 * bdrv_parse_filename. 429 */ 430 const char *protocol_name; 431 432 /* 433 * Truncate @bs to @offset bytes using the given @prealloc mode 434 * when growing. Modes other than PREALLOC_MODE_OFF should be 435 * rejected when shrinking @bs. 436 * 437 * If @exact is true, @bs must be resized to exactly @offset. 438 * Otherwise, it is sufficient for @bs (if it is a host block 439 * device and thus there is no way to resize it) to be at least 440 * @offset bytes in length. 441 * 442 * If @exact is true and this function fails but would succeed 443 * with @exact = false, it should return -ENOTSUP. 444 */ 445 int coroutine_fn (*bdrv_co_truncate)(BlockDriverState *bs, int64_t offset, 446 bool exact, PreallocMode prealloc, 447 BdrvRequestFlags flags, Error **errp); 448 449 int64_t (*bdrv_getlength)(BlockDriverState *bs); 450 bool has_variable_length; 451 int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs); 452 BlockMeasureInfo *(*bdrv_measure)(QemuOpts *opts, BlockDriverState *in_bs, 453 Error **errp); 454 455 int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs, 456 int64_t offset, int64_t bytes, QEMUIOVector *qiov); 457 int coroutine_fn (*bdrv_co_pwritev_compressed_part)(BlockDriverState *bs, 458 int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset); 459 460 int (*bdrv_snapshot_create)(BlockDriverState *bs, 461 QEMUSnapshotInfo *sn_info); 462 int (*bdrv_snapshot_goto)(BlockDriverState *bs, 463 const char *snapshot_id); 464 int (*bdrv_snapshot_delete)(BlockDriverState *bs, 465 const char *snapshot_id, 466 const char *name, 467 Error **errp); 468 int (*bdrv_snapshot_list)(BlockDriverState *bs, 469 QEMUSnapshotInfo **psn_info); 470 int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs, 471 const char *snapshot_id, 472 const char *name, 473 Error **errp); 474 int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi); 475 ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs, 476 Error **errp); 477 BlockStatsSpecific *(*bdrv_get_specific_stats)(BlockDriverState *bs); 478 479 int coroutine_fn (*bdrv_save_vmstate)(BlockDriverState *bs, 480 QEMUIOVector *qiov, 481 int64_t pos); 482 int coroutine_fn (*bdrv_load_vmstate)(BlockDriverState *bs, 483 QEMUIOVector *qiov, 484 int64_t pos); 485 486 int (*bdrv_change_backing_file)(BlockDriverState *bs, 487 const char *backing_file, const char *backing_fmt); 488 489 /* removable device specific */ 490 bool (*bdrv_is_inserted)(BlockDriverState *bs); 491 void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag); 492 void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked); 493 494 /* to control generic scsi devices */ 495 BlockAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs, 496 unsigned long int req, void *buf, 497 BlockCompletionFunc *cb, void *opaque); 498 int coroutine_fn (*bdrv_co_ioctl)(BlockDriverState *bs, 499 unsigned long int req, void *buf); 500 501 /* List of options for creating images, terminated by name == NULL */ 502 QemuOptsList *create_opts; 503 504 /* List of options for image amend */ 505 QemuOptsList *amend_opts; 506 507 /* 508 * If this driver supports reopening images this contains a 509 * NULL-terminated list of the runtime options that can be 510 * modified. If an option in this list is unspecified during 511 * reopen then it _must_ be reset to its default value or return 512 * an error. 513 */ 514 const char *const *mutable_opts; 515 516 /* 517 * Returns 0 for completed check, -errno for internal errors. 518 * The check results are stored in result. 519 */ 520 int coroutine_fn (*bdrv_co_check)(BlockDriverState *bs, 521 BdrvCheckResult *result, 522 BdrvCheckMode fix); 523 524 void (*bdrv_debug_event)(BlockDriverState *bs, BlkdebugEvent event); 525 526 /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */ 527 int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event, 528 const char *tag); 529 int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs, 530 const char *tag); 531 int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag); 532 bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag); 533 534 void (*bdrv_refresh_limits)(BlockDriverState *bs, Error **errp); 535 536 /* 537 * Returns 1 if newly created images are guaranteed to contain only 538 * zeros, 0 otherwise. 539 */ 540 int (*bdrv_has_zero_init)(BlockDriverState *bs); 541 542 /* Remove fd handlers, timers, and other event loop callbacks so the event 543 * loop is no longer in use. Called with no in-flight requests and in 544 * depth-first traversal order with parents before child nodes. 545 */ 546 void (*bdrv_detach_aio_context)(BlockDriverState *bs); 547 548 /* Add fd handlers, timers, and other event loop callbacks so I/O requests 549 * can be processed again. Called with no in-flight requests and in 550 * depth-first traversal order with child nodes before parent nodes. 551 */ 552 void (*bdrv_attach_aio_context)(BlockDriverState *bs, 553 AioContext *new_context); 554 555 /* io queue for linux-aio */ 556 void (*bdrv_io_plug)(BlockDriverState *bs); 557 void (*bdrv_io_unplug)(BlockDriverState *bs); 558 559 /** 560 * Try to get @bs's logical and physical block size. 561 * On success, store them in @bsz and return zero. 562 * On failure, return negative errno. 563 */ 564 int (*bdrv_probe_blocksizes)(BlockDriverState *bs, BlockSizes *bsz); 565 /** 566 * Try to get @bs's geometry (cyls, heads, sectors) 567 * On success, store them in @geo and return 0. 568 * On failure return -errno. 569 * Only drivers that want to override guest geometry implement this 570 * callback; see hd_geometry_guess(). 571 */ 572 int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo); 573 574 /** 575 * bdrv_co_drain_begin is called if implemented in the beginning of a 576 * drain operation to drain and stop any internal sources of requests in 577 * the driver. 578 * bdrv_co_drain_end is called if implemented at the end of the drain. 579 * 580 * They should be used by the driver to e.g. manage scheduled I/O 581 * requests, or toggle an internal state. After the end of the drain new 582 * requests will continue normally. 583 */ 584 void coroutine_fn (*bdrv_co_drain_begin)(BlockDriverState *bs); 585 void coroutine_fn (*bdrv_co_drain_end)(BlockDriverState *bs); 586 587 void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child, 588 Error **errp); 589 void (*bdrv_del_child)(BlockDriverState *parent, BdrvChild *child, 590 Error **errp); 591 592 /** 593 * Informs the block driver that a permission change is intended. The 594 * driver checks whether the change is permissible and may take other 595 * preparations for the change (e.g. get file system locks). This operation 596 * is always followed either by a call to either .bdrv_set_perm or 597 * .bdrv_abort_perm_update. 598 * 599 * Checks whether the requested set of cumulative permissions in @perm 600 * can be granted for accessing @bs and whether no other users are using 601 * permissions other than those given in @shared (both arguments take 602 * BLK_PERM_* bitmasks). 603 * 604 * If both conditions are met, 0 is returned. Otherwise, -errno is returned 605 * and errp is set to an error describing the conflict. 606 */ 607 int (*bdrv_check_perm)(BlockDriverState *bs, uint64_t perm, 608 uint64_t shared, Error **errp); 609 610 /** 611 * Called to inform the driver that the set of cumulative set of used 612 * permissions for @bs has changed to @perm, and the set of sharable 613 * permission to @shared. The driver can use this to propagate changes to 614 * its children (i.e. request permissions only if a parent actually needs 615 * them). 616 * 617 * This function is only invoked after bdrv_check_perm(), so block drivers 618 * may rely on preparations made in their .bdrv_check_perm implementation. 619 */ 620 void (*bdrv_set_perm)(BlockDriverState *bs, uint64_t perm, uint64_t shared); 621 622 /* 623 * Called to inform the driver that after a previous bdrv_check_perm() 624 * call, the permission update is not performed and any preparations made 625 * for it (e.g. taken file locks) need to be undone. 626 * 627 * This function can be called even for nodes that never saw a 628 * bdrv_check_perm() call. It is a no-op then. 629 */ 630 void (*bdrv_abort_perm_update)(BlockDriverState *bs); 631 632 /** 633 * Returns in @nperm and @nshared the permissions that the driver for @bs 634 * needs on its child @c, based on the cumulative permissions requested by 635 * the parents in @parent_perm and @parent_shared. 636 * 637 * If @c is NULL, return the permissions for attaching a new child for the 638 * given @child_class and @role. 639 * 640 * If @reopen_queue is non-NULL, don't return the currently needed 641 * permissions, but those that will be needed after applying the 642 * @reopen_queue. 643 */ 644 void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c, 645 BdrvChildRole role, 646 BlockReopenQueue *reopen_queue, 647 uint64_t parent_perm, uint64_t parent_shared, 648 uint64_t *nperm, uint64_t *nshared); 649 650 bool (*bdrv_supports_persistent_dirty_bitmap)(BlockDriverState *bs); 651 bool (*bdrv_co_can_store_new_dirty_bitmap)(BlockDriverState *bs, 652 const char *name, 653 uint32_t granularity, 654 Error **errp); 655 int (*bdrv_co_remove_persistent_dirty_bitmap)(BlockDriverState *bs, 656 const char *name, 657 Error **errp); 658 659 /** 660 * Register/unregister a buffer for I/O. For example, when the driver is 661 * interested to know the memory areas that will later be used in iovs, so 662 * that it can do IOMMU mapping with VFIO etc., in order to get better 663 * performance. In the case of VFIO drivers, this callback is used to do 664 * DMA mapping for hot buffers. 665 */ 666 void (*bdrv_register_buf)(BlockDriverState *bs, void *host, size_t size); 667 void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host); 668 QLIST_ENTRY(BlockDriver) list; 669 670 /* Pointer to a NULL-terminated array of names of strong options 671 * that can be specified for bdrv_open(). A strong option is one 672 * that changes the data of a BDS. 673 * If this pointer is NULL, the array is considered empty. 674 * "filename" and "driver" are always considered strong. */ 675 const char *const *strong_runtime_opts; 676 }; 677 678 static inline bool block_driver_can_compress(BlockDriver *drv) 679 { 680 return drv->bdrv_co_pwritev_compressed || 681 drv->bdrv_co_pwritev_compressed_part; 682 } 683 684 typedef struct BlockLimits { 685 /* Alignment requirement, in bytes, for offset/length of I/O 686 * requests. Must be a power of 2 less than INT_MAX; defaults to 687 * 1 for drivers with modern byte interfaces, and to 512 688 * otherwise. */ 689 uint32_t request_alignment; 690 691 /* 692 * Maximum number of bytes that can be discarded at once. Must be multiple 693 * of pdiscard_alignment, but need not be power of 2. May be 0 if no 694 * inherent 64-bit limit. 695 */ 696 int64_t max_pdiscard; 697 698 /* Optimal alignment for discard requests in bytes. A power of 2 699 * is best but not mandatory. Must be a multiple of 700 * bl.request_alignment, and must be less than max_pdiscard if 701 * that is set. May be 0 if bl.request_alignment is good enough */ 702 uint32_t pdiscard_alignment; 703 704 /* 705 * Maximum number of bytes that can zeroized at once. Must be multiple of 706 * pwrite_zeroes_alignment. 0 means no limit. 707 */ 708 int64_t max_pwrite_zeroes; 709 710 /* Optimal alignment for write zeroes requests in bytes. A power 711 * of 2 is best but not mandatory. Must be a multiple of 712 * bl.request_alignment, and must be less than max_pwrite_zeroes 713 * if that is set. May be 0 if bl.request_alignment is good 714 * enough */ 715 uint32_t pwrite_zeroes_alignment; 716 717 /* Optimal transfer length in bytes. A power of 2 is best but not 718 * mandatory. Must be a multiple of bl.request_alignment, or 0 if 719 * no preferred size */ 720 uint32_t opt_transfer; 721 722 /* Maximal transfer length in bytes. Need not be power of 2, but 723 * must be multiple of opt_transfer and bl.request_alignment, or 0 724 * for no 32-bit limit. For now, anything larger than INT_MAX is 725 * clamped down. */ 726 uint32_t max_transfer; 727 728 /* Maximal hardware transfer length in bytes. Applies whenever 729 * transfers to the device bypass the kernel I/O scheduler, for 730 * example with SG_IO. If larger than max_transfer or if zero, 731 * blk_get_max_hw_transfer will fall back to max_transfer. 732 */ 733 uint64_t max_hw_transfer; 734 735 /* Maximal number of scatter/gather elements allowed by the hardware. 736 * Applies whenever transfers to the device bypass the kernel I/O 737 * scheduler, for example with SG_IO. If larger than max_iov 738 * or if zero, blk_get_max_hw_iov will fall back to max_iov. 739 */ 740 int max_hw_iov; 741 742 /* memory alignment, in bytes so that no bounce buffer is needed */ 743 size_t min_mem_alignment; 744 745 /* memory alignment, in bytes, for bounce buffer */ 746 size_t opt_mem_alignment; 747 748 /* maximum number of iovec elements */ 749 int max_iov; 750 } BlockLimits; 751 752 typedef struct BdrvOpBlocker BdrvOpBlocker; 753 754 typedef struct BdrvAioNotifier { 755 void (*attached_aio_context)(AioContext *new_context, void *opaque); 756 void (*detach_aio_context)(void *opaque); 757 758 void *opaque; 759 bool deleted; 760 761 QLIST_ENTRY(BdrvAioNotifier) list; 762 } BdrvAioNotifier; 763 764 struct BdrvChildClass { 765 /* If true, bdrv_replace_node() doesn't change the node this BdrvChild 766 * points to. */ 767 bool stay_at_node; 768 769 /* If true, the parent is a BlockDriverState and bdrv_next_all_states() 770 * will return it. This information is used for drain_all, where every node 771 * will be drained separately, so the drain only needs to be propagated to 772 * non-BDS parents. */ 773 bool parent_is_bds; 774 775 void (*inherit_options)(BdrvChildRole role, bool parent_is_format, 776 int *child_flags, QDict *child_options, 777 int parent_flags, QDict *parent_options); 778 779 void (*change_media)(BdrvChild *child, bool load); 780 void (*resize)(BdrvChild *child); 781 782 /* Returns a name that is supposedly more useful for human users than the 783 * node name for identifying the node in question (in particular, a BB 784 * name), or NULL if the parent can't provide a better name. */ 785 const char *(*get_name)(BdrvChild *child); 786 787 /* Returns a malloced string that describes the parent of the child for a 788 * human reader. This could be a node-name, BlockBackend name, qdev ID or 789 * QOM path of the device owning the BlockBackend, job type and ID etc. The 790 * caller is responsible for freeing the memory. */ 791 char *(*get_parent_desc)(BdrvChild *child); 792 793 /* 794 * If this pair of functions is implemented, the parent doesn't issue new 795 * requests after returning from .drained_begin() until .drained_end() is 796 * called. 797 * 798 * These functions must not change the graph (and therefore also must not 799 * call aio_poll(), which could change the graph indirectly). 800 * 801 * If drained_end() schedules background operations, it must atomically 802 * increment *drained_end_counter for each such operation and atomically 803 * decrement it once the operation has settled. 804 * 805 * Note that this can be nested. If drained_begin() was called twice, new 806 * I/O is allowed only after drained_end() was called twice, too. 807 */ 808 void (*drained_begin)(BdrvChild *child); 809 void (*drained_end)(BdrvChild *child, int *drained_end_counter); 810 811 /* 812 * Returns whether the parent has pending requests for the child. This 813 * callback is polled after .drained_begin() has been called until all 814 * activity on the child has stopped. 815 */ 816 bool (*drained_poll)(BdrvChild *child); 817 818 /* Notifies the parent that the child has been activated/inactivated (e.g. 819 * when migration is completing) and it can start/stop requesting 820 * permissions and doing I/O on it. */ 821 void (*activate)(BdrvChild *child, Error **errp); 822 int (*inactivate)(BdrvChild *child); 823 824 void (*attach)(BdrvChild *child); 825 void (*detach)(BdrvChild *child); 826 827 /* Notifies the parent that the filename of its child has changed (e.g. 828 * because the direct child was removed from the backing chain), so that it 829 * can update its reference. */ 830 int (*update_filename)(BdrvChild *child, BlockDriverState *new_base, 831 const char *filename, Error **errp); 832 833 bool (*can_set_aio_ctx)(BdrvChild *child, AioContext *ctx, 834 GSList **ignore, Error **errp); 835 void (*set_aio_ctx)(BdrvChild *child, AioContext *ctx, GSList **ignore); 836 837 AioContext *(*get_parent_aio_context)(BdrvChild *child); 838 }; 839 840 extern const BdrvChildClass child_of_bds; 841 842 struct BdrvChild { 843 BlockDriverState *bs; 844 char *name; 845 const BdrvChildClass *klass; 846 BdrvChildRole role; 847 void *opaque; 848 849 /** 850 * Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask) 851 */ 852 uint64_t perm; 853 854 /** 855 * Permissions that can still be granted to other users of @bs while this 856 * BdrvChild is still attached to it. (BLK_PERM_* bitmask) 857 */ 858 uint64_t shared_perm; 859 860 /* 861 * This link is frozen: the child can neither be replaced nor 862 * detached from the parent. 863 */ 864 bool frozen; 865 866 /* 867 * How many times the parent of this child has been drained 868 * (through klass->drained_*). 869 * Usually, this is equal to bs->quiesce_counter (potentially 870 * reduced by bdrv_drain_all_count). It may differ while the 871 * child is entering or leaving a drained section. 872 */ 873 int parent_quiesce_counter; 874 875 QLIST_ENTRY(BdrvChild) next; 876 QLIST_ENTRY(BdrvChild) next_parent; 877 }; 878 879 /* 880 * Allows bdrv_co_block_status() to cache one data region for a 881 * protocol node. 882 * 883 * @valid: Whether the cache is valid (should be accessed with atomic 884 * functions so this can be reset by RCU readers) 885 * @data_start: Offset where we know (or strongly assume) is data 886 * @data_end: Offset where the data region ends (which is not necessarily 887 * the start of a zeroed region) 888 */ 889 typedef struct BdrvBlockStatusCache { 890 struct rcu_head rcu; 891 892 bool valid; 893 int64_t data_start; 894 int64_t data_end; 895 } BdrvBlockStatusCache; 896 897 struct BlockDriverState { 898 /* Protected by big QEMU lock or read-only after opening. No special 899 * locking needed during I/O... 900 */ 901 int open_flags; /* flags used to open the file, re-used for re-open */ 902 bool encrypted; /* if true, the media is encrypted */ 903 bool sg; /* if true, the device is a /dev/sg* */ 904 bool probed; /* if true, format was probed rather than specified */ 905 bool force_share; /* if true, always allow all shared permissions */ 906 bool implicit; /* if true, this filter node was automatically inserted */ 907 908 BlockDriver *drv; /* NULL means no media */ 909 void *opaque; 910 911 AioContext *aio_context; /* event loop used for fd handlers, timers, etc */ 912 /* long-running tasks intended to always use the same AioContext as this 913 * BDS may register themselves in this list to be notified of changes 914 * regarding this BDS's context */ 915 QLIST_HEAD(, BdrvAioNotifier) aio_notifiers; 916 bool walking_aio_notifiers; /* to make removal during iteration safe */ 917 918 char filename[PATH_MAX]; 919 /* 920 * If not empty, this image is a diff in relation to backing_file. 921 * Note that this is the name given in the image header and 922 * therefore may or may not be equal to .backing->bs->filename. 923 * If this field contains a relative path, it is to be resolved 924 * relatively to the overlay's location. 925 */ 926 char backing_file[PATH_MAX]; 927 /* 928 * The backing filename indicated by the image header. Contrary 929 * to backing_file, if we ever open this file, auto_backing_file 930 * is replaced by the resulting BDS's filename (i.e. after a 931 * bdrv_refresh_filename() run). 932 */ 933 char auto_backing_file[PATH_MAX]; 934 char backing_format[16]; /* if non-zero and backing_file exists */ 935 936 QDict *full_open_options; 937 char exact_filename[PATH_MAX]; 938 939 BdrvChild *backing; 940 BdrvChild *file; 941 942 /* I/O Limits */ 943 BlockLimits bl; 944 945 /* 946 * Flags honored during pread 947 */ 948 unsigned int supported_read_flags; 949 /* Flags honored during pwrite (so far: BDRV_REQ_FUA, 950 * BDRV_REQ_WRITE_UNCHANGED). 951 * If a driver does not support BDRV_REQ_WRITE_UNCHANGED, those 952 * writes will be issued as normal writes without the flag set. 953 * This is important to note for drivers that do not explicitly 954 * request a WRITE permission for their children and instead take 955 * the same permissions as their parent did (this is commonly what 956 * block filters do). Such drivers have to be aware that the 957 * parent may have taken a WRITE_UNCHANGED permission only and is 958 * issuing such requests. Drivers either must make sure that 959 * these requests do not result in plain WRITE accesses (usually 960 * by supporting BDRV_REQ_WRITE_UNCHANGED, and then forwarding 961 * every incoming write request as-is, including potentially that 962 * flag), or they have to explicitly take the WRITE permission for 963 * their children. */ 964 unsigned int supported_write_flags; 965 /* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA, 966 * BDRV_REQ_MAY_UNMAP, BDRV_REQ_WRITE_UNCHANGED) */ 967 unsigned int supported_zero_flags; 968 /* 969 * Flags honoured during truncate (so far: BDRV_REQ_ZERO_WRITE). 970 * 971 * If BDRV_REQ_ZERO_WRITE is given, the truncate operation must make sure 972 * that any added space reads as all zeros. If this can't be guaranteed, 973 * the operation must fail. 974 */ 975 unsigned int supported_truncate_flags; 976 977 /* the following member gives a name to every node on the bs graph. */ 978 char node_name[32]; 979 /* element of the list of named nodes building the graph */ 980 QTAILQ_ENTRY(BlockDriverState) node_list; 981 /* element of the list of all BlockDriverStates (all_bdrv_states) */ 982 QTAILQ_ENTRY(BlockDriverState) bs_list; 983 /* element of the list of monitor-owned BDS */ 984 QTAILQ_ENTRY(BlockDriverState) monitor_list; 985 int refcnt; 986 987 /* operation blockers */ 988 QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; 989 990 /* The node that this node inherited default options from (and a reopen on 991 * which can affect this node by changing these defaults). This is always a 992 * parent node of this node. */ 993 BlockDriverState *inherits_from; 994 QLIST_HEAD(, BdrvChild) children; 995 QLIST_HEAD(, BdrvChild) parents; 996 997 QDict *options; 998 QDict *explicit_options; 999 BlockdevDetectZeroesOptions detect_zeroes; 1000 1001 /* The error object in use for blocking operations on backing_hd */ 1002 Error *backing_blocker; 1003 1004 /* Protected by AioContext lock */ 1005 1006 /* If we are reading a disk image, give its size in sectors. 1007 * Generally read-only; it is written to by load_snapshot and 1008 * save_snaphost, but the block layer is quiescent during those. 1009 */ 1010 int64_t total_sectors; 1011 1012 /* threshold limit for writes, in bytes. "High water mark". */ 1013 uint64_t write_threshold_offset; 1014 1015 /* Writing to the list requires the BQL _and_ the dirty_bitmap_mutex. 1016 * Reading from the list can be done with either the BQL or the 1017 * dirty_bitmap_mutex. Modifying a bitmap only requires 1018 * dirty_bitmap_mutex. */ 1019 QemuMutex dirty_bitmap_mutex; 1020 QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps; 1021 1022 /* Offset after the highest byte written to */ 1023 Stat64 wr_highest_offset; 1024 1025 /* If true, copy read backing sectors into image. Can be >1 if more 1026 * than one client has requested copy-on-read. Accessed with atomic 1027 * ops. 1028 */ 1029 int copy_on_read; 1030 1031 /* number of in-flight requests; overall and serialising. 1032 * Accessed with atomic ops. 1033 */ 1034 unsigned int in_flight; 1035 unsigned int serialising_in_flight; 1036 1037 /* counter for nested bdrv_io_plug. 1038 * Accessed with atomic ops. 1039 */ 1040 unsigned io_plugged; 1041 1042 /* do we need to tell the quest if we have a volatile write cache? */ 1043 int enable_write_cache; 1044 1045 /* Accessed with atomic ops. */ 1046 int quiesce_counter; 1047 int recursive_quiesce_counter; 1048 1049 unsigned int write_gen; /* Current data generation */ 1050 1051 /* Protected by reqs_lock. */ 1052 CoMutex reqs_lock; 1053 QLIST_HEAD(, BdrvTrackedRequest) tracked_requests; 1054 CoQueue flush_queue; /* Serializing flush queue */ 1055 bool active_flush_req; /* Flush request in flight? */ 1056 1057 /* Only read/written by whoever has set active_flush_req to true. */ 1058 unsigned int flushed_gen; /* Flushed write generation */ 1059 1060 /* BdrvChild links to this node may never be frozen */ 1061 bool never_freeze; 1062 1063 /* Lock for block-status cache RCU writers */ 1064 CoMutex bsc_modify_lock; 1065 /* Always non-NULL, but must only be dereferenced under an RCU read guard */ 1066 BdrvBlockStatusCache *block_status_cache; 1067 }; 1068 1069 struct BlockBackendRootState { 1070 int open_flags; 1071 BlockdevDetectZeroesOptions detect_zeroes; 1072 }; 1073 1074 typedef enum BlockMirrorBackingMode { 1075 /* Reuse the existing backing chain from the source for the target. 1076 * - sync=full: Set backing BDS to NULL. 1077 * - sync=top: Use source's backing BDS. 1078 * - sync=none: Use source as the backing BDS. */ 1079 MIRROR_SOURCE_BACKING_CHAIN, 1080 1081 /* Open the target's backing chain completely anew */ 1082 MIRROR_OPEN_BACKING_CHAIN, 1083 1084 /* Do not change the target's backing BDS after job completion */ 1085 MIRROR_LEAVE_BACKING_CHAIN, 1086 } BlockMirrorBackingMode; 1087 1088 1089 /* Essential block drivers which must always be statically linked into qemu, and 1090 * which therefore can be accessed without using bdrv_find_format() */ 1091 extern BlockDriver bdrv_file; 1092 extern BlockDriver bdrv_raw; 1093 extern BlockDriver bdrv_qcow2; 1094 1095 int coroutine_fn bdrv_co_preadv(BdrvChild *child, 1096 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 1097 BdrvRequestFlags flags); 1098 int coroutine_fn bdrv_co_preadv_part(BdrvChild *child, 1099 int64_t offset, int64_t bytes, 1100 QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags); 1101 int coroutine_fn bdrv_co_pwritev(BdrvChild *child, 1102 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 1103 BdrvRequestFlags flags); 1104 int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child, 1105 int64_t offset, int64_t bytes, 1106 QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags); 1107 1108 static inline int coroutine_fn bdrv_co_pread(BdrvChild *child, 1109 int64_t offset, unsigned int bytes, void *buf, BdrvRequestFlags flags) 1110 { 1111 QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); 1112 1113 return bdrv_co_preadv(child, offset, bytes, &qiov, flags); 1114 } 1115 1116 static inline int coroutine_fn bdrv_co_pwrite(BdrvChild *child, 1117 int64_t offset, unsigned int bytes, void *buf, BdrvRequestFlags flags) 1118 { 1119 QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); 1120 1121 return bdrv_co_pwritev(child, offset, bytes, &qiov, flags); 1122 } 1123 1124 extern unsigned int bdrv_drain_all_count; 1125 void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent); 1126 void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent); 1127 1128 bool coroutine_fn bdrv_make_request_serialising(BdrvTrackedRequest *req, 1129 uint64_t align); 1130 BdrvTrackedRequest *coroutine_fn bdrv_co_get_self_request(BlockDriverState *bs); 1131 1132 int get_tmp_filename(char *filename, int size); 1133 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size, 1134 const char *filename); 1135 1136 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, 1137 QDict *options); 1138 1139 /** 1140 * bdrv_add_aio_context_notifier: 1141 * 1142 * If a long-running job intends to be always run in the same AioContext as a 1143 * certain BDS, it may use this function to be notified of changes regarding the 1144 * association of the BDS to an AioContext. 1145 * 1146 * attached_aio_context() is called after the target BDS has been attached to a 1147 * new AioContext; detach_aio_context() is called before the target BDS is being 1148 * detached from its old AioContext. 1149 */ 1150 void bdrv_add_aio_context_notifier(BlockDriverState *bs, 1151 void (*attached_aio_context)(AioContext *new_context, void *opaque), 1152 void (*detach_aio_context)(void *opaque), void *opaque); 1153 1154 /** 1155 * bdrv_remove_aio_context_notifier: 1156 * 1157 * Unsubscribe of change notifications regarding the BDS's AioContext. The 1158 * parameters given here have to be the same as those given to 1159 * bdrv_add_aio_context_notifier(). 1160 */ 1161 void bdrv_remove_aio_context_notifier(BlockDriverState *bs, 1162 void (*aio_context_attached)(AioContext *, 1163 void *), 1164 void (*aio_context_detached)(void *), 1165 void *opaque); 1166 1167 /** 1168 * bdrv_wakeup: 1169 * @bs: The BlockDriverState for which an I/O operation has been completed. 1170 * 1171 * Wake up the main thread if it is waiting on BDRV_POLL_WHILE. During 1172 * synchronous I/O on a BlockDriverState that is attached to another 1173 * I/O thread, the main thread lets the I/O thread's event loop run, 1174 * waiting for the I/O operation to complete. A bdrv_wakeup will wake 1175 * up the main thread if necessary. 1176 * 1177 * Manual calls to bdrv_wakeup are rarely necessary, because 1178 * bdrv_dec_in_flight already calls it. 1179 */ 1180 void bdrv_wakeup(BlockDriverState *bs); 1181 1182 #ifdef _WIN32 1183 int is_windows_drive(const char *filename); 1184 #endif 1185 1186 /** 1187 * stream_start: 1188 * @job_id: The id of the newly-created job, or %NULL to use the 1189 * device name of @bs. 1190 * @bs: Block device to operate on. 1191 * @base: Block device that will become the new base, or %NULL to 1192 * flatten the whole backing file chain onto @bs. 1193 * @backing_file_str: The file name that will be written to @bs as the 1194 * the new backing file if the job completes. Ignored if @base is %NULL. 1195 * @creation_flags: Flags that control the behavior of the Job lifetime. 1196 * See @BlockJobCreateFlags 1197 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 1198 * @on_error: The action to take upon error. 1199 * @filter_node_name: The node name that should be assigned to the filter 1200 * driver that the stream job inserts into the graph above 1201 * @bs. NULL means that a node name should be autogenerated. 1202 * @errp: Error object. 1203 * 1204 * Start a streaming operation on @bs. Clusters that are unallocated 1205 * in @bs, but allocated in any image between @base and @bs (both 1206 * exclusive) will be written to @bs. At the end of a successful 1207 * streaming job, the backing file of @bs will be changed to 1208 * @backing_file_str in the written image and to @base in the live 1209 * BlockDriverState. 1210 */ 1211 void stream_start(const char *job_id, BlockDriverState *bs, 1212 BlockDriverState *base, const char *backing_file_str, 1213 BlockDriverState *bottom, 1214 int creation_flags, int64_t speed, 1215 BlockdevOnError on_error, 1216 const char *filter_node_name, 1217 Error **errp); 1218 1219 /** 1220 * commit_start: 1221 * @job_id: The id of the newly-created job, or %NULL to use the 1222 * device name of @bs. 1223 * @bs: Active block device. 1224 * @top: Top block device to be committed. 1225 * @base: Block device that will be written into, and become the new top. 1226 * @creation_flags: Flags that control the behavior of the Job lifetime. 1227 * See @BlockJobCreateFlags 1228 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 1229 * @on_error: The action to take upon error. 1230 * @backing_file_str: String to use as the backing file in @top's overlay 1231 * @filter_node_name: The node name that should be assigned to the filter 1232 * driver that the commit job inserts into the graph above @top. NULL means 1233 * that a node name should be autogenerated. 1234 * @errp: Error object. 1235 * 1236 */ 1237 void commit_start(const char *job_id, BlockDriverState *bs, 1238 BlockDriverState *base, BlockDriverState *top, 1239 int creation_flags, int64_t speed, 1240 BlockdevOnError on_error, const char *backing_file_str, 1241 const char *filter_node_name, Error **errp); 1242 /** 1243 * commit_active_start: 1244 * @job_id: The id of the newly-created job, or %NULL to use the 1245 * device name of @bs. 1246 * @bs: Active block device to be committed. 1247 * @base: Block device that will be written into, and become the new top. 1248 * @creation_flags: Flags that control the behavior of the Job lifetime. 1249 * See @BlockJobCreateFlags 1250 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 1251 * @on_error: The action to take upon error. 1252 * @filter_node_name: The node name that should be assigned to the filter 1253 * driver that the commit job inserts into the graph above @bs. NULL means that 1254 * a node name should be autogenerated. 1255 * @cb: Completion function for the job. 1256 * @opaque: Opaque pointer value passed to @cb. 1257 * @auto_complete: Auto complete the job. 1258 * @errp: Error object. 1259 * 1260 */ 1261 BlockJob *commit_active_start(const char *job_id, BlockDriverState *bs, 1262 BlockDriverState *base, int creation_flags, 1263 int64_t speed, BlockdevOnError on_error, 1264 const char *filter_node_name, 1265 BlockCompletionFunc *cb, void *opaque, 1266 bool auto_complete, Error **errp); 1267 /* 1268 * mirror_start: 1269 * @job_id: The id of the newly-created job, or %NULL to use the 1270 * device name of @bs. 1271 * @bs: Block device to operate on. 1272 * @target: Block device to write to. 1273 * @replaces: Block graph node name to replace once the mirror is done. Can 1274 * only be used when full mirroring is selected. 1275 * @creation_flags: Flags that control the behavior of the Job lifetime. 1276 * See @BlockJobCreateFlags 1277 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 1278 * @granularity: The chosen granularity for the dirty bitmap. 1279 * @buf_size: The amount of data that can be in flight at one time. 1280 * @mode: Whether to collapse all images in the chain to the target. 1281 * @backing_mode: How to establish the target's backing chain after completion. 1282 * @zero_target: Whether the target should be explicitly zero-initialized 1283 * @on_source_error: The action to take upon error reading from the source. 1284 * @on_target_error: The action to take upon error writing to the target. 1285 * @unmap: Whether to unmap target where source sectors only contain zeroes. 1286 * @filter_node_name: The node name that should be assigned to the filter 1287 * driver that the mirror job inserts into the graph above @bs. NULL means that 1288 * a node name should be autogenerated. 1289 * @copy_mode: When to trigger writes to the target. 1290 * @errp: Error object. 1291 * 1292 * Start a mirroring operation on @bs. Clusters that are allocated 1293 * in @bs will be written to @target until the job is cancelled or 1294 * manually completed. At the end of a successful mirroring job, 1295 * @bs will be switched to read from @target. 1296 */ 1297 void mirror_start(const char *job_id, BlockDriverState *bs, 1298 BlockDriverState *target, const char *replaces, 1299 int creation_flags, int64_t speed, 1300 uint32_t granularity, int64_t buf_size, 1301 MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, 1302 bool zero_target, 1303 BlockdevOnError on_source_error, 1304 BlockdevOnError on_target_error, 1305 bool unmap, const char *filter_node_name, 1306 MirrorCopyMode copy_mode, Error **errp); 1307 1308 /* 1309 * backup_job_create: 1310 * @job_id: The id of the newly-created job, or %NULL to use the 1311 * device name of @bs. 1312 * @bs: Block device to operate on. 1313 * @target: Block device to write to. 1314 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 1315 * @sync_mode: What parts of the disk image should be copied to the destination. 1316 * @sync_bitmap: The dirty bitmap if sync_mode is 'bitmap' or 'incremental' 1317 * @bitmap_mode: The bitmap synchronization policy to use. 1318 * @perf: Performance options. All actual fields assumed to be present, 1319 * all ".has_*" fields are ignored. 1320 * @on_source_error: The action to take upon error reading from the source. 1321 * @on_target_error: The action to take upon error writing to the target. 1322 * @creation_flags: Flags that control the behavior of the Job lifetime. 1323 * See @BlockJobCreateFlags 1324 * @cb: Completion function for the job. 1325 * @opaque: Opaque pointer value passed to @cb. 1326 * @txn: Transaction that this job is part of (may be NULL). 1327 * 1328 * Create a backup operation on @bs. Clusters in @bs are written to @target 1329 * until the job is cancelled or manually completed. 1330 */ 1331 BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, 1332 BlockDriverState *target, int64_t speed, 1333 MirrorSyncMode sync_mode, 1334 BdrvDirtyBitmap *sync_bitmap, 1335 BitmapSyncMode bitmap_mode, 1336 bool compress, 1337 const char *filter_node_name, 1338 BackupPerf *perf, 1339 BlockdevOnError on_source_error, 1340 BlockdevOnError on_target_error, 1341 int creation_flags, 1342 BlockCompletionFunc *cb, void *opaque, 1343 JobTxn *txn, Error **errp); 1344 1345 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, 1346 const char *child_name, 1347 const BdrvChildClass *child_class, 1348 BdrvChildRole child_role, 1349 uint64_t perm, uint64_t shared_perm, 1350 void *opaque, Error **errp); 1351 void bdrv_root_unref_child(BdrvChild *child); 1352 1353 void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm, 1354 uint64_t *shared_perm); 1355 1356 /** 1357 * Sets a BdrvChild's permissions. Avoid if the parent is a BDS; use 1358 * bdrv_child_refresh_perms() instead and make the parent's 1359 * .bdrv_child_perm() implementation return the correct values. 1360 */ 1361 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, 1362 Error **errp); 1363 1364 /** 1365 * Calls bs->drv->bdrv_child_perm() and updates the child's permission 1366 * masks with the result. 1367 * Drivers should invoke this function whenever an event occurs that 1368 * makes their .bdrv_child_perm() implementation return different 1369 * values than before, but which will not result in the block layer 1370 * automatically refreshing the permissions. 1371 */ 1372 int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp); 1373 1374 bool bdrv_recurse_can_replace(BlockDriverState *bs, 1375 BlockDriverState *to_replace); 1376 1377 /* 1378 * Default implementation for BlockDriver.bdrv_child_perm() that can 1379 * be used by block filters and image formats, as long as they use the 1380 * child_of_bds child class and set an appropriate BdrvChildRole. 1381 */ 1382 void bdrv_default_perms(BlockDriverState *bs, BdrvChild *c, 1383 BdrvChildRole role, BlockReopenQueue *reopen_queue, 1384 uint64_t perm, uint64_t shared, 1385 uint64_t *nperm, uint64_t *nshared); 1386 1387 const char *bdrv_get_parent_name(const BlockDriverState *bs); 1388 void blk_dev_change_media_cb(BlockBackend *blk, bool load, Error **errp); 1389 bool blk_dev_has_removable_media(BlockBackend *blk); 1390 bool blk_dev_has_tray(BlockBackend *blk); 1391 void blk_dev_eject_request(BlockBackend *blk, bool force); 1392 bool blk_dev_is_tray_open(BlockBackend *blk); 1393 bool blk_dev_is_medium_locked(BlockBackend *blk); 1394 1395 void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes); 1396 1397 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out); 1398 void bdrv_restore_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *backup); 1399 bool bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest, 1400 const BdrvDirtyBitmap *src, 1401 HBitmap **backup, bool lock); 1402 1403 void bdrv_inc_in_flight(BlockDriverState *bs); 1404 void bdrv_dec_in_flight(BlockDriverState *bs); 1405 1406 void blockdev_close_all_bdrv_states(void); 1407 1408 int coroutine_fn bdrv_co_copy_range_from(BdrvChild *src, int64_t src_offset, 1409 BdrvChild *dst, int64_t dst_offset, 1410 int64_t bytes, 1411 BdrvRequestFlags read_flags, 1412 BdrvRequestFlags write_flags); 1413 int coroutine_fn bdrv_co_copy_range_to(BdrvChild *src, int64_t src_offset, 1414 BdrvChild *dst, int64_t dst_offset, 1415 int64_t bytes, 1416 BdrvRequestFlags read_flags, 1417 BdrvRequestFlags write_flags); 1418 1419 int refresh_total_sectors(BlockDriverState *bs, int64_t hint); 1420 1421 void bdrv_set_monitor_owned(BlockDriverState *bs); 1422 BlockDriverState *bds_tree_init(QDict *bs_opts, Error **errp); 1423 1424 /** 1425 * Simple implementation of bdrv_co_create_opts for protocol drivers 1426 * which only support creation via opening a file 1427 * (usually existing raw storage device) 1428 */ 1429 int coroutine_fn bdrv_co_create_opts_simple(BlockDriver *drv, 1430 const char *filename, 1431 QemuOpts *opts, 1432 Error **errp); 1433 extern QemuOptsList bdrv_create_opts_simple; 1434 1435 BdrvDirtyBitmap *block_dirty_bitmap_lookup(const char *node, 1436 const char *name, 1437 BlockDriverState **pbs, 1438 Error **errp); 1439 BdrvDirtyBitmap *block_dirty_bitmap_merge(const char *node, const char *target, 1440 BlockDirtyBitmapMergeSourceList *bms, 1441 HBitmap **backup, Error **errp); 1442 BdrvDirtyBitmap *block_dirty_bitmap_remove(const char *node, const char *name, 1443 bool release, 1444 BlockDriverState **bitmap_bs, 1445 Error **errp); 1446 1447 BdrvChild *bdrv_cow_child(BlockDriverState *bs); 1448 BdrvChild *bdrv_filter_child(BlockDriverState *bs); 1449 BdrvChild *bdrv_filter_or_cow_child(BlockDriverState *bs); 1450 BdrvChild *bdrv_primary_child(BlockDriverState *bs); 1451 BlockDriverState *bdrv_skip_implicit_filters(BlockDriverState *bs); 1452 BlockDriverState *bdrv_skip_filters(BlockDriverState *bs); 1453 BlockDriverState *bdrv_backing_chain_next(BlockDriverState *bs); 1454 1455 static inline BlockDriverState *child_bs(BdrvChild *child) 1456 { 1457 return child ? child->bs : NULL; 1458 } 1459 1460 static inline BlockDriverState *bdrv_cow_bs(BlockDriverState *bs) 1461 { 1462 return child_bs(bdrv_cow_child(bs)); 1463 } 1464 1465 static inline BlockDriverState *bdrv_filter_bs(BlockDriverState *bs) 1466 { 1467 return child_bs(bdrv_filter_child(bs)); 1468 } 1469 1470 static inline BlockDriverState *bdrv_filter_or_cow_bs(BlockDriverState *bs) 1471 { 1472 return child_bs(bdrv_filter_or_cow_child(bs)); 1473 } 1474 1475 static inline BlockDriverState *bdrv_primary_bs(BlockDriverState *bs) 1476 { 1477 return child_bs(bdrv_primary_child(bs)); 1478 } 1479 1480 /** 1481 * End all quiescent sections started by bdrv_drain_all_begin(). This is 1482 * needed when deleting a BDS before bdrv_drain_all_end() is called. 1483 * 1484 * NOTE: this is an internal helper for bdrv_close() *only*. No one else 1485 * should call it. 1486 */ 1487 void bdrv_drain_all_end_quiesce(BlockDriverState *bs); 1488 1489 /** 1490 * Check whether the given offset is in the cached block-status data 1491 * region. 1492 * 1493 * If it is, and @pnum is not NULL, *pnum is set to 1494 * `bsc.data_end - offset`, i.e. how many bytes, starting from 1495 * @offset, are data (according to the cache). 1496 * Otherwise, *pnum is not touched. 1497 */ 1498 bool bdrv_bsc_is_data(BlockDriverState *bs, int64_t offset, int64_t *pnum); 1499 1500 /** 1501 * If [offset, offset + bytes) overlaps with the currently cached 1502 * block-status region, invalidate the cache. 1503 * 1504 * (To be used by I/O paths that cause data regions to be zero or 1505 * holes.) 1506 */ 1507 void bdrv_bsc_invalidate_range(BlockDriverState *bs, 1508 int64_t offset, int64_t bytes); 1509 1510 /** 1511 * Mark the range [offset, offset + bytes) as a data region. 1512 */ 1513 void bdrv_bsc_fill(BlockDriverState *bs, int64_t offset, int64_t bytes); 1514 1515 #endif /* BLOCK_INT_H */ 1516