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_COMMON_H 25 #define BLOCK_INT_COMMON_H 26 27 #include "block/aio.h" 28 #include "block/block-common.h" 29 #include "block/block-global-state.h" 30 #include "block/snapshot.h" 31 #include "qemu/iov.h" 32 #include "qemu/rcu.h" 33 #include "qemu/stats64.h" 34 35 #define BLOCK_FLAG_LAZY_REFCOUNTS 8 36 37 #define BLOCK_OPT_SIZE "size" 38 #define BLOCK_OPT_ENCRYPT "encryption" 39 #define BLOCK_OPT_ENCRYPT_FORMAT "encrypt.format" 40 #define BLOCK_OPT_COMPAT6 "compat6" 41 #define BLOCK_OPT_HWVERSION "hwversion" 42 #define BLOCK_OPT_BACKING_FILE "backing_file" 43 #define BLOCK_OPT_BACKING_FMT "backing_fmt" 44 #define BLOCK_OPT_CLUSTER_SIZE "cluster_size" 45 #define BLOCK_OPT_TABLE_SIZE "table_size" 46 #define BLOCK_OPT_PREALLOC "preallocation" 47 #define BLOCK_OPT_SUBFMT "subformat" 48 #define BLOCK_OPT_COMPAT_LEVEL "compat" 49 #define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts" 50 #define BLOCK_OPT_ADAPTER_TYPE "adapter_type" 51 #define BLOCK_OPT_REDUNDANCY "redundancy" 52 #define BLOCK_OPT_NOCOW "nocow" 53 #define BLOCK_OPT_EXTENT_SIZE_HINT "extent_size_hint" 54 #define BLOCK_OPT_OBJECT_SIZE "object_size" 55 #define BLOCK_OPT_REFCOUNT_BITS "refcount_bits" 56 #define BLOCK_OPT_DATA_FILE "data_file" 57 #define BLOCK_OPT_DATA_FILE_RAW "data_file_raw" 58 #define BLOCK_OPT_COMPRESSION_TYPE "compression_type" 59 #define BLOCK_OPT_EXTL2 "extended_l2" 60 61 #define BLOCK_PROBE_BUF_SIZE 512 62 63 enum BdrvTrackedRequestType { 64 BDRV_TRACKED_READ, 65 BDRV_TRACKED_WRITE, 66 BDRV_TRACKED_DISCARD, 67 BDRV_TRACKED_TRUNCATE, 68 }; 69 70 /* 71 * That is not quite good that BdrvTrackedRequest structure is public, 72 * as block/io.c is very careful about incoming offset/bytes being 73 * correct. Be sure to assert bdrv_check_request() succeeded after any 74 * modification of BdrvTrackedRequest object out of block/io.c 75 */ 76 typedef struct BdrvTrackedRequest { 77 BlockDriverState *bs; 78 int64_t offset; 79 int64_t bytes; 80 enum BdrvTrackedRequestType type; 81 82 bool serialising; 83 int64_t overlap_offset; 84 int64_t overlap_bytes; 85 86 QLIST_ENTRY(BdrvTrackedRequest) list; 87 Coroutine *co; /* owner, used for deadlock detection */ 88 CoQueue wait_queue; /* coroutines blocked on this request */ 89 90 struct BdrvTrackedRequest *waiting_for; 91 } BdrvTrackedRequest; 92 93 94 struct BlockDriver { 95 /* 96 * These fields are initialized when this object is created, 97 * and are never changed afterwards. 98 */ 99 100 const char *format_name; 101 int instance_size; 102 103 /* 104 * Set to true if the BlockDriver is a block filter. Block filters pass 105 * certain callbacks that refer to data (see block.c) to their bs->file 106 * or bs->backing (whichever one exists) if the driver doesn't implement 107 * them. Drivers that do not wish to forward must implement them and return 108 * -ENOTSUP. 109 * Note that filters are not allowed to modify data. 110 * 111 * Filters generally cannot have more than a single filtered child, 112 * because the data they present must at all times be the same as 113 * that on their filtered child. That would be impossible to 114 * achieve for multiple filtered children. 115 * (And this filtered child must then be bs->file or bs->backing.) 116 */ 117 bool is_filter; 118 /* 119 * Only make sense for filter drivers, for others must be false. 120 * If true, filtered child is bs->backing. Otherwise it's bs->file. 121 * Two internal filters use bs->backing as filtered child and has this 122 * field set to true: mirror_top and commit_top. There also two such test 123 * filters in tests/unit/test-bdrv-graph-mod.c. 124 * 125 * Never create any more such filters! 126 * 127 * TODO: imagine how to deprecate this behavior and make all filters work 128 * similarly using bs->file as filtered child. 129 */ 130 bool filtered_child_is_backing; 131 132 /* 133 * Set to true if the BlockDriver is a format driver. Format nodes 134 * generally do not expect their children to be other format nodes 135 * (except for backing files), and so format probing is disabled 136 * on those children. 137 */ 138 bool is_format; 139 140 /* 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 bool has_variable_length; 162 163 /* 164 * Drivers setting this field must be able to work with just a plain 165 * filename with '<protocol_name>:' as a prefix, and no other options. 166 * Options may be extracted from the filename by implementing 167 * bdrv_parse_filename. 168 */ 169 const char *protocol_name; 170 171 /* List of options for creating images, terminated by name == NULL */ 172 QemuOptsList *create_opts; 173 174 /* List of options for image amend */ 175 QemuOptsList *amend_opts; 176 177 /* 178 * If this driver supports reopening images this contains a 179 * NULL-terminated list of the runtime options that can be 180 * modified. If an option in this list is unspecified during 181 * reopen then it _must_ be reset to its default value or return 182 * an error. 183 */ 184 const char *const *mutable_opts; 185 186 /* 187 * Pointer to a NULL-terminated array of names of strong options 188 * that can be specified for bdrv_open(). A strong option is one 189 * that changes the data of a BDS. 190 * If this pointer is NULL, the array is considered empty. 191 * "filename" and "driver" are always considered strong. 192 */ 193 const char *const *strong_runtime_opts; 194 195 196 /* 197 * Global state (GS) API. These functions run under the BQL. 198 * 199 * See include/block/block-global-state.h for more information about 200 * the GS API. 201 */ 202 203 /* 204 * This function is invoked under BQL before .bdrv_co_amend() 205 * (which in contrast does not necessarily run under the BQL) 206 * to allow driver-specific initialization code that requires 207 * the BQL, like setting up specific permission flags. 208 */ 209 int (*bdrv_amend_pre_run)(BlockDriverState *bs, Error **errp); 210 /* 211 * This function is invoked under BQL after .bdrv_co_amend() 212 * to allow cleaning up what was done in .bdrv_amend_pre_run(). 213 */ 214 void (*bdrv_amend_clean)(BlockDriverState *bs); 215 216 /* 217 * Return true if @to_replace can be replaced by a BDS with the 218 * same data as @bs without it affecting @bs's behavior (that is, 219 * without it being visible to @bs's parents). 220 */ 221 bool (*bdrv_recurse_can_replace)(BlockDriverState *bs, 222 BlockDriverState *to_replace); 223 224 int (*bdrv_probe_device)(const char *filename); 225 226 /* 227 * Any driver implementing this callback is expected to be able to handle 228 * NULL file names in its .bdrv_open() implementation. 229 */ 230 void (*bdrv_parse_filename)(const char *filename, QDict *options, 231 Error **errp); 232 233 /* For handling image reopen for split or non-split files. */ 234 int (*bdrv_reopen_prepare)(BDRVReopenState *reopen_state, 235 BlockReopenQueue *queue, Error **errp); 236 void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state); 237 void (*bdrv_reopen_commit_post)(BDRVReopenState *reopen_state); 238 void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state); 239 void (*bdrv_join_options)(QDict *options, QDict *old_options); 240 241 int (*bdrv_open)(BlockDriverState *bs, QDict *options, int flags, 242 Error **errp); 243 244 /* Protocol drivers should implement this instead of bdrv_open */ 245 int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags, 246 Error **errp); 247 void (*bdrv_close)(BlockDriverState *bs); 248 249 int coroutine_fn (*bdrv_co_create)(BlockdevCreateOptions *opts, 250 Error **errp); 251 int coroutine_fn (*bdrv_co_create_opts)(BlockDriver *drv, 252 const char *filename, 253 QemuOpts *opts, 254 Error **errp); 255 256 int (*bdrv_amend_options)(BlockDriverState *bs, 257 QemuOpts *opts, 258 BlockDriverAmendStatusCB *status_cb, 259 void *cb_opaque, 260 bool force, 261 Error **errp); 262 263 int (*bdrv_make_empty)(BlockDriverState *bs); 264 265 /* 266 * Refreshes the bs->exact_filename field. If that is impossible, 267 * bs->exact_filename has to be left empty. 268 */ 269 void (*bdrv_refresh_filename)(BlockDriverState *bs); 270 271 /* 272 * Gathers the open options for all children into @target. 273 * A simple format driver (without backing file support) might 274 * implement this function like this: 275 * 276 * QINCREF(bs->file->bs->full_open_options); 277 * qdict_put(target, "file", bs->file->bs->full_open_options); 278 * 279 * If not specified, the generic implementation will simply put 280 * all children's options under their respective name. 281 * 282 * @backing_overridden is true when bs->backing seems not to be 283 * the child that would result from opening bs->backing_file. 284 * Therefore, if it is true, the backing child's options should be 285 * gathered; otherwise, there is no need since the backing child 286 * is the one implied by the image header. 287 * 288 * Note that ideally this function would not be needed. Every 289 * block driver which implements it is probably doing something 290 * shady regarding its runtime option structure. 291 */ 292 void (*bdrv_gather_child_options)(BlockDriverState *bs, QDict *target, 293 bool backing_overridden); 294 295 /* 296 * Returns an allocated string which is the directory name of this BDS: It 297 * will be used to make relative filenames absolute by prepending this 298 * function's return value to them. 299 */ 300 char *(*bdrv_dirname)(BlockDriverState *bs, Error **errp); 301 302 /* 303 * This informs the driver that we are no longer interested in the result 304 * of in-flight requests, so don't waste the time if possible. 305 * 306 * One example usage is to avoid waiting for an nbd target node reconnect 307 * timeout during job-cancel with force=true. 308 */ 309 void (*bdrv_cancel_in_flight)(BlockDriverState *bs); 310 311 int (*bdrv_inactivate)(BlockDriverState *bs); 312 313 int (*bdrv_snapshot_create)(BlockDriverState *bs, 314 QEMUSnapshotInfo *sn_info); 315 int (*bdrv_snapshot_goto)(BlockDriverState *bs, 316 const char *snapshot_id); 317 int (*bdrv_snapshot_delete)(BlockDriverState *bs, 318 const char *snapshot_id, 319 const char *name, 320 Error **errp); 321 int (*bdrv_snapshot_list)(BlockDriverState *bs, 322 QEMUSnapshotInfo **psn_info); 323 int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs, 324 const char *snapshot_id, 325 const char *name, 326 Error **errp); 327 328 int (*bdrv_change_backing_file)(BlockDriverState *bs, 329 const char *backing_file, const char *backing_fmt); 330 331 /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */ 332 int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event, 333 const char *tag); 334 int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs, 335 const char *tag); 336 int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag); 337 bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag); 338 339 void (*bdrv_refresh_limits)(BlockDriverState *bs, Error **errp); 340 341 /* 342 * Returns 1 if newly created images are guaranteed to contain only 343 * zeros, 0 otherwise. 344 */ 345 int (*bdrv_has_zero_init)(BlockDriverState *bs); 346 347 /* 348 * Remove fd handlers, timers, and other event loop callbacks so the event 349 * loop is no longer in use. Called with no in-flight requests and in 350 * depth-first traversal order with parents before child nodes. 351 */ 352 void (*bdrv_detach_aio_context)(BlockDriverState *bs); 353 354 /* 355 * Add fd handlers, timers, and other event loop callbacks so I/O requests 356 * can be processed again. Called with no in-flight requests and in 357 * depth-first traversal order with child nodes before parent nodes. 358 */ 359 void (*bdrv_attach_aio_context)(BlockDriverState *bs, 360 AioContext *new_context); 361 362 /** 363 * Try to get @bs's logical and physical block size. 364 * On success, store them in @bsz and return zero. 365 * On failure, return negative errno. 366 */ 367 int (*bdrv_probe_blocksizes)(BlockDriverState *bs, BlockSizes *bsz); 368 /** 369 * Try to get @bs's geometry (cyls, heads, sectors) 370 * On success, store them in @geo and return 0. 371 * On failure return -errno. 372 * Only drivers that want to override guest geometry implement this 373 * callback; see hd_geometry_guess(). 374 */ 375 int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo); 376 377 void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child, 378 Error **errp); 379 void (*bdrv_del_child)(BlockDriverState *parent, BdrvChild *child, 380 Error **errp); 381 382 /** 383 * Informs the block driver that a permission change is intended. The 384 * driver checks whether the change is permissible and may take other 385 * preparations for the change (e.g. get file system locks). This operation 386 * is always followed either by a call to either .bdrv_set_perm or 387 * .bdrv_abort_perm_update. 388 * 389 * Checks whether the requested set of cumulative permissions in @perm 390 * can be granted for accessing @bs and whether no other users are using 391 * permissions other than those given in @shared (both arguments take 392 * BLK_PERM_* bitmasks). 393 * 394 * If both conditions are met, 0 is returned. Otherwise, -errno is returned 395 * and errp is set to an error describing the conflict. 396 */ 397 int (*bdrv_check_perm)(BlockDriverState *bs, uint64_t perm, 398 uint64_t shared, Error **errp); 399 400 /** 401 * Called to inform the driver that the set of cumulative set of used 402 * permissions for @bs has changed to @perm, and the set of sharable 403 * permission to @shared. The driver can use this to propagate changes to 404 * its children (i.e. request permissions only if a parent actually needs 405 * them). 406 * 407 * This function is only invoked after bdrv_check_perm(), so block drivers 408 * may rely on preparations made in their .bdrv_check_perm implementation. 409 */ 410 void (*bdrv_set_perm)(BlockDriverState *bs, uint64_t perm, uint64_t shared); 411 412 /* 413 * Called to inform the driver that after a previous bdrv_check_perm() 414 * call, the permission update is not performed and any preparations made 415 * for it (e.g. taken file locks) need to be undone. 416 * 417 * This function can be called even for nodes that never saw a 418 * bdrv_check_perm() call. It is a no-op then. 419 */ 420 void (*bdrv_abort_perm_update)(BlockDriverState *bs); 421 422 /** 423 * Returns in @nperm and @nshared the permissions that the driver for @bs 424 * needs on its child @c, based on the cumulative permissions requested by 425 * the parents in @parent_perm and @parent_shared. 426 * 427 * If @c is NULL, return the permissions for attaching a new child for the 428 * given @child_class and @role. 429 * 430 * If @reopen_queue is non-NULL, don't return the currently needed 431 * permissions, but those that will be needed after applying the 432 * @reopen_queue. 433 */ 434 void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c, 435 BdrvChildRole role, 436 BlockReopenQueue *reopen_queue, 437 uint64_t parent_perm, uint64_t parent_shared, 438 uint64_t *nperm, uint64_t *nshared); 439 440 /** 441 * Register/unregister a buffer for I/O. For example, when the driver is 442 * interested to know the memory areas that will later be used in iovs, so 443 * that it can do IOMMU mapping with VFIO etc., in order to get better 444 * performance. In the case of VFIO drivers, this callback is used to do 445 * DMA mapping for hot buffers. 446 * 447 * Returns: true on success, false on failure 448 */ 449 bool (*bdrv_register_buf)(BlockDriverState *bs, void *host, size_t size, 450 Error **errp); 451 void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host, size_t size); 452 453 /* 454 * This field is modified only under the BQL, and is part of 455 * the global state. 456 */ 457 QLIST_ENTRY(BlockDriver) list; 458 459 /* 460 * I/O API functions. These functions are thread-safe. 461 * 462 * See include/block/block-io.h for more information about 463 * the I/O API. 464 */ 465 466 int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename); 467 468 int coroutine_fn (*bdrv_co_amend)(BlockDriverState *bs, 469 BlockdevAmendOptions *opts, 470 bool force, 471 Error **errp); 472 473 /* aio */ 474 BlockAIOCB *(*bdrv_aio_preadv)(BlockDriverState *bs, 475 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 476 BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); 477 BlockAIOCB *(*bdrv_aio_pwritev)(BlockDriverState *bs, 478 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 479 BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); 480 BlockAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs, 481 BlockCompletionFunc *cb, void *opaque); 482 BlockAIOCB *(*bdrv_aio_pdiscard)(BlockDriverState *bs, 483 int64_t offset, int bytes, 484 BlockCompletionFunc *cb, void *opaque); 485 486 int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs, 487 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); 488 489 /** 490 * @offset: position in bytes to read at 491 * @bytes: number of bytes to read 492 * @qiov: the buffers to fill with read data 493 * @flags: currently unused, always 0 494 * 495 * @offset and @bytes will be a multiple of 'request_alignment', 496 * but the length of individual @qiov elements does not have to 497 * be a multiple. 498 * 499 * @bytes will always equal the total size of @qiov, and will be 500 * no larger than 'max_transfer'. 501 * 502 * The buffer in @qiov may point directly to guest memory. 503 */ 504 int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs, 505 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 506 BdrvRequestFlags flags); 507 508 int coroutine_fn (*bdrv_co_preadv_part)(BlockDriverState *bs, 509 int64_t offset, int64_t bytes, 510 QEMUIOVector *qiov, size_t qiov_offset, 511 BdrvRequestFlags flags); 512 513 int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs, 514 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, 515 int flags); 516 /** 517 * @offset: position in bytes to write at 518 * @bytes: number of bytes to write 519 * @qiov: the buffers containing data to write 520 * @flags: zero or more bits allowed by 'supported_write_flags' 521 * 522 * @offset and @bytes will be a multiple of 'request_alignment', 523 * but the length of individual @qiov elements does not have to 524 * be a multiple. 525 * 526 * @bytes will always equal the total size of @qiov, and will be 527 * no larger than 'max_transfer'. 528 * 529 * The buffer in @qiov may point directly to guest memory. 530 */ 531 int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs, 532 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 533 BdrvRequestFlags flags); 534 int coroutine_fn (*bdrv_co_pwritev_part)(BlockDriverState *bs, 535 int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset, 536 BdrvRequestFlags flags); 537 538 /* 539 * Efficiently zero a region of the disk image. Typically an image format 540 * would use a compact metadata representation to implement this. This 541 * function pointer may be NULL or return -ENOSUP and .bdrv_co_writev() 542 * will be called instead. 543 */ 544 int coroutine_fn (*bdrv_co_pwrite_zeroes)(BlockDriverState *bs, 545 int64_t offset, int64_t bytes, BdrvRequestFlags flags); 546 int coroutine_fn (*bdrv_co_pdiscard)(BlockDriverState *bs, 547 int64_t offset, int64_t bytes); 548 549 /* 550 * Map [offset, offset + nbytes) range onto a child of @bs to copy from, 551 * and invoke bdrv_co_copy_range_from(child, ...), or invoke 552 * bdrv_co_copy_range_to() if @bs is the leaf child to copy data from. 553 * 554 * See the comment of bdrv_co_copy_range for the parameter and return value 555 * semantics. 556 */ 557 int coroutine_fn (*bdrv_co_copy_range_from)(BlockDriverState *bs, 558 BdrvChild *src, 559 int64_t offset, 560 BdrvChild *dst, 561 int64_t dst_offset, 562 int64_t bytes, 563 BdrvRequestFlags read_flags, 564 BdrvRequestFlags write_flags); 565 566 /* 567 * Map [offset, offset + nbytes) range onto a child of bs to copy data to, 568 * and invoke bdrv_co_copy_range_to(child, src, ...), or perform the copy 569 * operation if @bs is the leaf and @src has the same BlockDriver. Return 570 * -ENOTSUP if @bs is the leaf but @src has a different BlockDriver. 571 * 572 * See the comment of bdrv_co_copy_range for the parameter and return value 573 * semantics. 574 */ 575 int coroutine_fn (*bdrv_co_copy_range_to)(BlockDriverState *bs, 576 BdrvChild *src, 577 int64_t src_offset, 578 BdrvChild *dst, 579 int64_t dst_offset, 580 int64_t bytes, 581 BdrvRequestFlags read_flags, 582 BdrvRequestFlags write_flags); 583 584 /* 585 * Building block for bdrv_block_status[_above] and 586 * bdrv_is_allocated[_above]. The driver should answer only 587 * according to the current layer, and should only need to set 588 * BDRV_BLOCK_DATA, BDRV_BLOCK_ZERO, BDRV_BLOCK_OFFSET_VALID, 589 * and/or BDRV_BLOCK_RAW; if the current layer defers to a backing 590 * layer, the result should be 0 (and not BDRV_BLOCK_ZERO). See 591 * block.h for the overall meaning of the bits. As a hint, the 592 * flag want_zero is true if the caller cares more about precise 593 * mappings (favor accurate _OFFSET_VALID/_ZERO) or false for 594 * overall allocation (favor larger *pnum, perhaps by reporting 595 * _DATA instead of _ZERO). The block layer guarantees input 596 * clamped to bdrv_getlength() and aligned to request_alignment, 597 * as well as non-NULL pnum, map, and file; in turn, the driver 598 * must return an error or set pnum to an aligned non-zero value. 599 * 600 * Note that @bytes is just a hint on how big of a region the 601 * caller wants to inspect. It is not a limit on *pnum. 602 * Implementations are free to return larger values of *pnum if 603 * doing so does not incur a performance penalty. 604 * 605 * block/io.c's bdrv_co_block_status() will utilize an unclamped 606 * *pnum value for the block-status cache on protocol nodes, prior 607 * to clamping *pnum for return to its caller. 608 */ 609 int coroutine_fn (*bdrv_co_block_status)(BlockDriverState *bs, 610 bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum, 611 int64_t *map, BlockDriverState **file); 612 613 /* 614 * Snapshot-access API. 615 * 616 * Block-driver may provide snapshot-access API: special functions to access 617 * some internal "snapshot". The functions are similar with normal 618 * read/block_status/discard handler, but don't have any specific handling 619 * in generic block-layer: no serializing, no alignment, no tracked 620 * requests. So, block-driver that realizes these APIs is fully responsible 621 * for synchronization between snapshot-access API and normal IO requests. 622 * 623 * TODO: To be able to support qcow2's internal snapshots, this API will 624 * need to be extended to: 625 * - be able to select a specific snapshot 626 * - receive the snapshot's actual length (which may differ from bs's 627 * length) 628 */ 629 int coroutine_fn (*bdrv_co_preadv_snapshot)(BlockDriverState *bs, 630 int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset); 631 int coroutine_fn (*bdrv_co_snapshot_block_status)(BlockDriverState *bs, 632 bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum, 633 int64_t *map, BlockDriverState **file); 634 int coroutine_fn (*bdrv_co_pdiscard_snapshot)(BlockDriverState *bs, 635 int64_t offset, int64_t bytes); 636 637 /* 638 * Invalidate any cached meta-data. 639 */ 640 void coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_invalidate_cache)( 641 BlockDriverState *bs, Error **errp); 642 643 /* 644 * Flushes all data for all layers by calling bdrv_co_flush for underlying 645 * layers, if needed. This function is needed for deterministic 646 * synchronization of the flush finishing callback. 647 */ 648 int coroutine_fn (*bdrv_co_flush)(BlockDriverState *bs); 649 650 /* Delete a created file. */ 651 int coroutine_fn (*bdrv_co_delete_file)(BlockDriverState *bs, 652 Error **errp); 653 654 /* 655 * Flushes all data that was already written to the OS all the way down to 656 * the disk (for example file-posix.c calls fsync()). 657 */ 658 int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs); 659 660 /* 661 * Flushes all internal caches to the OS. The data may still sit in a 662 * writeback cache of the host OS, but it will survive a crash of the qemu 663 * process. 664 */ 665 int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs); 666 667 /* 668 * Truncate @bs to @offset bytes using the given @prealloc mode 669 * when growing. Modes other than PREALLOC_MODE_OFF should be 670 * rejected when shrinking @bs. 671 * 672 * If @exact is true, @bs must be resized to exactly @offset. 673 * Otherwise, it is sufficient for @bs (if it is a host block 674 * device and thus there is no way to resize it) to be at least 675 * @offset bytes in length. 676 * 677 * If @exact is true and this function fails but would succeed 678 * with @exact = false, it should return -ENOTSUP. 679 */ 680 int coroutine_fn (*bdrv_co_truncate)(BlockDriverState *bs, int64_t offset, 681 bool exact, PreallocMode prealloc, 682 BdrvRequestFlags flags, Error **errp); 683 int64_t coroutine_fn (*bdrv_co_getlength)(BlockDriverState *bs); 684 int64_t coroutine_fn (*bdrv_co_get_allocated_file_size)( 685 BlockDriverState *bs); 686 687 BlockMeasureInfo *(*bdrv_measure)(QemuOpts *opts, BlockDriverState *in_bs, 688 Error **errp); 689 690 int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs, 691 int64_t offset, int64_t bytes, QEMUIOVector *qiov); 692 int coroutine_fn (*bdrv_co_pwritev_compressed_part)(BlockDriverState *bs, 693 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 694 size_t qiov_offset); 695 696 int coroutine_fn (*bdrv_co_get_info)(BlockDriverState *bs, 697 BlockDriverInfo *bdi); 698 699 ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs, 700 Error **errp); 701 BlockStatsSpecific *(*bdrv_get_specific_stats)(BlockDriverState *bs); 702 703 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_save_vmstate)( 704 BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); 705 706 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_load_vmstate)( 707 BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); 708 709 /* removable device specific */ 710 bool coroutine_fn (*bdrv_co_is_inserted)(BlockDriverState *bs); 711 void coroutine_fn (*bdrv_co_eject)(BlockDriverState *bs, bool eject_flag); 712 void coroutine_fn (*bdrv_co_lock_medium)(BlockDriverState *bs, bool locked); 713 714 /* to control generic scsi devices */ 715 BlockAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs, 716 unsigned long int req, void *buf, 717 BlockCompletionFunc *cb, void *opaque); 718 int coroutine_fn (*bdrv_co_ioctl)(BlockDriverState *bs, 719 unsigned long int req, void *buf); 720 721 /* 722 * Returns 0 for completed check, -errno for internal errors. 723 * The check results are stored in result. 724 */ 725 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_check)( 726 BlockDriverState *bs, BdrvCheckResult *result, BdrvCheckMode fix); 727 728 void coroutine_fn (*bdrv_co_debug_event)(BlockDriverState *bs, 729 BlkdebugEvent event); 730 731 /* io queue for linux-aio */ 732 void coroutine_fn (*bdrv_co_io_plug)(BlockDriverState *bs); 733 void coroutine_fn (*bdrv_co_io_unplug)(BlockDriverState *bs); 734 735 /** 736 * bdrv_drain_begin is called if implemented in the beginning of a 737 * drain operation to drain and stop any internal sources of requests in 738 * the driver. 739 * bdrv_drain_end is called if implemented at the end of the drain. 740 * 741 * They should be used by the driver to e.g. manage scheduled I/O 742 * requests, or toggle an internal state. After the end of the drain new 743 * requests will continue normally. 744 * 745 * Implementations of both functions must not call aio_poll(). 746 */ 747 void (*bdrv_drain_begin)(BlockDriverState *bs); 748 void (*bdrv_drain_end)(BlockDriverState *bs); 749 750 bool (*bdrv_supports_persistent_dirty_bitmap)(BlockDriverState *bs); 751 bool coroutine_fn (*bdrv_co_can_store_new_dirty_bitmap)( 752 BlockDriverState *bs, const char *name, uint32_t granularity, 753 Error **errp); 754 int coroutine_fn (*bdrv_co_remove_persistent_dirty_bitmap)( 755 BlockDriverState *bs, const char *name, Error **errp); 756 }; 757 758 static inline bool block_driver_can_compress(BlockDriver *drv) 759 { 760 return drv->bdrv_co_pwritev_compressed || 761 drv->bdrv_co_pwritev_compressed_part; 762 } 763 764 typedef struct BlockLimits { 765 /* 766 * Alignment requirement, in bytes, for offset/length of I/O 767 * requests. Must be a power of 2 less than INT_MAX; defaults to 768 * 1 for drivers with modern byte interfaces, and to 512 769 * otherwise. 770 */ 771 uint32_t request_alignment; 772 773 /* 774 * Maximum number of bytes that can be discarded at once. Must be multiple 775 * of pdiscard_alignment, but need not be power of 2. May be 0 if no 776 * inherent 64-bit limit. 777 */ 778 int64_t max_pdiscard; 779 780 /* 781 * Optimal alignment for discard requests in bytes. A power of 2 782 * is best but not mandatory. Must be a multiple of 783 * bl.request_alignment, and must be less than max_pdiscard if 784 * that is set. May be 0 if bl.request_alignment is good enough 785 */ 786 uint32_t pdiscard_alignment; 787 788 /* 789 * Maximum number of bytes that can zeroized at once. Must be multiple of 790 * pwrite_zeroes_alignment. 0 means no limit. 791 */ 792 int64_t max_pwrite_zeroes; 793 794 /* 795 * Optimal alignment for write zeroes requests in bytes. A power 796 * of 2 is best but not mandatory. Must be a multiple of 797 * bl.request_alignment, and must be less than max_pwrite_zeroes 798 * if that is set. May be 0 if bl.request_alignment is good 799 * enough 800 */ 801 uint32_t pwrite_zeroes_alignment; 802 803 /* 804 * Optimal transfer length in bytes. A power of 2 is best but not 805 * mandatory. Must be a multiple of bl.request_alignment, or 0 if 806 * no preferred size 807 */ 808 uint32_t opt_transfer; 809 810 /* 811 * Maximal transfer length in bytes. Need not be power of 2, but 812 * must be multiple of opt_transfer and bl.request_alignment, or 0 813 * for no 32-bit limit. For now, anything larger than INT_MAX is 814 * clamped down. 815 */ 816 uint32_t max_transfer; 817 818 /* 819 * Maximal hardware transfer length in bytes. Applies whenever 820 * transfers to the device bypass the kernel I/O scheduler, for 821 * example with SG_IO. If larger than max_transfer or if zero, 822 * blk_get_max_hw_transfer will fall back to max_transfer. 823 */ 824 uint64_t max_hw_transfer; 825 826 /* 827 * Maximal number of scatter/gather elements allowed by the hardware. 828 * Applies whenever transfers to the device bypass the kernel I/O 829 * scheduler, for example with SG_IO. If larger than max_iov 830 * or if zero, blk_get_max_hw_iov will fall back to max_iov. 831 */ 832 int max_hw_iov; 833 834 835 /* memory alignment, in bytes so that no bounce buffer is needed */ 836 size_t min_mem_alignment; 837 838 /* memory alignment, in bytes, for bounce buffer */ 839 size_t opt_mem_alignment; 840 841 /* maximum number of iovec elements */ 842 int max_iov; 843 } BlockLimits; 844 845 typedef struct BdrvOpBlocker BdrvOpBlocker; 846 847 typedef struct BdrvAioNotifier { 848 void (*attached_aio_context)(AioContext *new_context, void *opaque); 849 void (*detach_aio_context)(void *opaque); 850 851 void *opaque; 852 bool deleted; 853 854 QLIST_ENTRY(BdrvAioNotifier) list; 855 } BdrvAioNotifier; 856 857 struct BdrvChildClass { 858 /* 859 * If true, bdrv_replace_node() doesn't change the node this BdrvChild 860 * points to. 861 */ 862 bool stay_at_node; 863 864 /* 865 * If true, the parent is a BlockDriverState and bdrv_next_all_states() 866 * will return it. This information is used for drain_all, where every node 867 * will be drained separately, so the drain only needs to be propagated to 868 * non-BDS parents. 869 */ 870 bool parent_is_bds; 871 872 /* 873 * Global state (GS) API. These functions run under the BQL. 874 * 875 * See include/block/block-global-state.h for more information about 876 * the GS API. 877 */ 878 void (*inherit_options)(BdrvChildRole role, bool parent_is_format, 879 int *child_flags, QDict *child_options, 880 int parent_flags, QDict *parent_options); 881 void (*change_media)(BdrvChild *child, bool load); 882 883 /* 884 * Returns a malloced string that describes the parent of the child for a 885 * human reader. This could be a node-name, BlockBackend name, qdev ID or 886 * QOM path of the device owning the BlockBackend, job type and ID etc. The 887 * caller is responsible for freeing the memory. 888 */ 889 char *(*get_parent_desc)(BdrvChild *child); 890 891 /* 892 * Notifies the parent that the child has been activated/inactivated (e.g. 893 * when migration is completing) and it can start/stop requesting 894 * permissions and doing I/O on it. 895 */ 896 void (*activate)(BdrvChild *child, Error **errp); 897 int (*inactivate)(BdrvChild *child); 898 899 void GRAPH_WRLOCK_PTR (*attach)(BdrvChild *child); 900 void GRAPH_WRLOCK_PTR (*detach)(BdrvChild *child); 901 902 /* 903 * Notifies the parent that the filename of its child has changed (e.g. 904 * because the direct child was removed from the backing chain), so that it 905 * can update its reference. 906 */ 907 int (*update_filename)(BdrvChild *child, BlockDriverState *new_base, 908 const char *filename, Error **errp); 909 910 bool (*change_aio_ctx)(BdrvChild *child, AioContext *ctx, 911 GHashTable *visited, Transaction *tran, 912 Error **errp); 913 914 /* 915 * I/O API functions. These functions are thread-safe. 916 * 917 * See include/block/block-io.h for more information about 918 * the I/O API. 919 */ 920 921 void (*resize)(BdrvChild *child); 922 923 /* 924 * Returns a name that is supposedly more useful for human users than the 925 * node name for identifying the node in question (in particular, a BB 926 * name), or NULL if the parent can't provide a better name. 927 */ 928 const char *(*get_name)(BdrvChild *child); 929 930 AioContext *(*get_parent_aio_context)(BdrvChild *child); 931 932 /* 933 * If this pair of functions is implemented, the parent doesn't issue new 934 * requests after returning from .drained_begin() until .drained_end() is 935 * called. 936 * 937 * These functions must not change the graph (and therefore also must not 938 * call aio_poll(), which could change the graph indirectly). 939 * 940 * Note that this can be nested. If drained_begin() was called twice, new 941 * I/O is allowed only after drained_end() was called twice, too. 942 */ 943 void (*drained_begin)(BdrvChild *child); 944 void (*drained_end)(BdrvChild *child); 945 946 /* 947 * Returns whether the parent has pending requests for the child. This 948 * callback is polled after .drained_begin() has been called until all 949 * activity on the child has stopped. 950 */ 951 bool (*drained_poll)(BdrvChild *child); 952 }; 953 954 extern const BdrvChildClass child_of_bds; 955 956 struct BdrvChild { 957 BlockDriverState *bs; 958 char *name; 959 const BdrvChildClass *klass; 960 BdrvChildRole role; 961 void *opaque; 962 963 /** 964 * Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask) 965 */ 966 uint64_t perm; 967 968 /** 969 * Permissions that can still be granted to other users of @bs while this 970 * BdrvChild is still attached to it. (BLK_PERM_* bitmask) 971 */ 972 uint64_t shared_perm; 973 974 /* 975 * This link is frozen: the child can neither be replaced nor 976 * detached from the parent. 977 */ 978 bool frozen; 979 980 /* 981 * True if the parent of this child has been drained by this BdrvChild 982 * (through klass->drained_*). 983 * 984 * It is generally true if bs->quiesce_counter > 0. It may differ while the 985 * child is entering or leaving a drained section. 986 */ 987 bool quiesced_parent; 988 989 QLIST_ENTRY(BdrvChild) next; 990 QLIST_ENTRY(BdrvChild) next_parent; 991 }; 992 993 /* 994 * Allows bdrv_co_block_status() to cache one data region for a 995 * protocol node. 996 * 997 * @valid: Whether the cache is valid (should be accessed with atomic 998 * functions so this can be reset by RCU readers) 999 * @data_start: Offset where we know (or strongly assume) is data 1000 * @data_end: Offset where the data region ends (which is not necessarily 1001 * the start of a zeroed region) 1002 */ 1003 typedef struct BdrvBlockStatusCache { 1004 struct rcu_head rcu; 1005 1006 bool valid; 1007 int64_t data_start; 1008 int64_t data_end; 1009 } BdrvBlockStatusCache; 1010 1011 struct BlockDriverState { 1012 /* 1013 * Protected by big QEMU lock or read-only after opening. No special 1014 * locking needed during I/O... 1015 */ 1016 int open_flags; /* flags used to open the file, re-used for re-open */ 1017 bool encrypted; /* if true, the media is encrypted */ 1018 bool sg; /* if true, the device is a /dev/sg* */ 1019 bool probed; /* if true, format was probed rather than specified */ 1020 bool force_share; /* if true, always allow all shared permissions */ 1021 bool implicit; /* if true, this filter node was automatically inserted */ 1022 1023 BlockDriver *drv; /* NULL means no media */ 1024 void *opaque; 1025 1026 AioContext *aio_context; /* event loop used for fd handlers, timers, etc */ 1027 /* 1028 * long-running tasks intended to always use the same AioContext as this 1029 * BDS may register themselves in this list to be notified of changes 1030 * regarding this BDS's context 1031 */ 1032 QLIST_HEAD(, BdrvAioNotifier) aio_notifiers; 1033 bool walking_aio_notifiers; /* to make removal during iteration safe */ 1034 1035 char filename[PATH_MAX]; 1036 /* 1037 * If not empty, this image is a diff in relation to backing_file. 1038 * Note that this is the name given in the image header and 1039 * therefore may or may not be equal to .backing->bs->filename. 1040 * If this field contains a relative path, it is to be resolved 1041 * relatively to the overlay's location. 1042 */ 1043 char backing_file[PATH_MAX]; 1044 /* 1045 * The backing filename indicated by the image header. Contrary 1046 * to backing_file, if we ever open this file, auto_backing_file 1047 * is replaced by the resulting BDS's filename (i.e. after a 1048 * bdrv_refresh_filename() run). 1049 */ 1050 char auto_backing_file[PATH_MAX]; 1051 char backing_format[16]; /* if non-zero and backing_file exists */ 1052 1053 QDict *full_open_options; 1054 char exact_filename[PATH_MAX]; 1055 1056 /* I/O Limits */ 1057 BlockLimits bl; 1058 1059 /* 1060 * Flags honored during pread 1061 */ 1062 BdrvRequestFlags supported_read_flags; 1063 /* 1064 * Flags honored during pwrite (so far: BDRV_REQ_FUA, 1065 * BDRV_REQ_WRITE_UNCHANGED). 1066 * If a driver does not support BDRV_REQ_WRITE_UNCHANGED, those 1067 * writes will be issued as normal writes without the flag set. 1068 * This is important to note for drivers that do not explicitly 1069 * request a WRITE permission for their children and instead take 1070 * the same permissions as their parent did (this is commonly what 1071 * block filters do). Such drivers have to be aware that the 1072 * parent may have taken a WRITE_UNCHANGED permission only and is 1073 * issuing such requests. Drivers either must make sure that 1074 * these requests do not result in plain WRITE accesses (usually 1075 * by supporting BDRV_REQ_WRITE_UNCHANGED, and then forwarding 1076 * every incoming write request as-is, including potentially that 1077 * flag), or they have to explicitly take the WRITE permission for 1078 * their children. 1079 */ 1080 BdrvRequestFlags supported_write_flags; 1081 /* 1082 * Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA, 1083 * BDRV_REQ_MAY_UNMAP, BDRV_REQ_WRITE_UNCHANGED) 1084 */ 1085 BdrvRequestFlags supported_zero_flags; 1086 /* 1087 * Flags honoured during truncate (so far: BDRV_REQ_ZERO_WRITE). 1088 * 1089 * If BDRV_REQ_ZERO_WRITE is given, the truncate operation must make sure 1090 * that any added space reads as all zeros. If this can't be guaranteed, 1091 * the operation must fail. 1092 */ 1093 BdrvRequestFlags supported_truncate_flags; 1094 1095 /* the following member gives a name to every node on the bs graph. */ 1096 char node_name[32]; 1097 /* element of the list of named nodes building the graph */ 1098 QTAILQ_ENTRY(BlockDriverState) node_list; 1099 /* element of the list of all BlockDriverStates (all_bdrv_states) */ 1100 QTAILQ_ENTRY(BlockDriverState) bs_list; 1101 /* element of the list of monitor-owned BDS */ 1102 QTAILQ_ENTRY(BlockDriverState) monitor_list; 1103 int refcnt; 1104 1105 /* operation blockers. Protected by BQL. */ 1106 QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; 1107 1108 /* 1109 * The node that this node inherited default options from (and a reopen on 1110 * which can affect this node by changing these defaults). This is always a 1111 * parent node of this node. 1112 */ 1113 BlockDriverState *inherits_from; 1114 1115 /* 1116 * @backing and @file are some of @children or NULL. All these three fields 1117 * (@file, @backing and @children) are modified only in 1118 * bdrv_child_cb_attach() and bdrv_child_cb_detach(). 1119 * 1120 * See also comment in include/block/block.h, to learn how backing and file 1121 * are connected with BdrvChildRole. 1122 */ 1123 QLIST_HEAD(, BdrvChild) children; 1124 BdrvChild *backing; 1125 BdrvChild *file; 1126 1127 QLIST_HEAD(, BdrvChild) parents; 1128 1129 QDict *options; 1130 QDict *explicit_options; 1131 BlockdevDetectZeroesOptions detect_zeroes; 1132 1133 /* The error object in use for blocking operations on backing_hd */ 1134 Error *backing_blocker; 1135 1136 /* Protected by AioContext lock */ 1137 1138 /* 1139 * If we are reading a disk image, give its size in sectors. 1140 * Generally read-only; it is written to by load_snapshot and 1141 * save_snaphost, but the block layer is quiescent during those. 1142 */ 1143 int64_t total_sectors; 1144 1145 /* threshold limit for writes, in bytes. "High water mark". */ 1146 uint64_t write_threshold_offset; 1147 1148 /* 1149 * Writing to the list requires the BQL _and_ the dirty_bitmap_mutex. 1150 * Reading from the list can be done with either the BQL or the 1151 * dirty_bitmap_mutex. Modifying a bitmap only requires 1152 * dirty_bitmap_mutex. 1153 */ 1154 QemuMutex dirty_bitmap_mutex; 1155 QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps; 1156 1157 /* Offset after the highest byte written to */ 1158 Stat64 wr_highest_offset; 1159 1160 /* 1161 * If true, copy read backing sectors into image. Can be >1 if more 1162 * than one client has requested copy-on-read. Accessed with atomic 1163 * ops. 1164 */ 1165 int copy_on_read; 1166 1167 /* 1168 * number of in-flight requests; overall and serialising. 1169 * Accessed with atomic ops. 1170 */ 1171 unsigned int in_flight; 1172 unsigned int serialising_in_flight; 1173 1174 /* 1175 * counter for nested bdrv_io_plug. 1176 * Accessed with atomic ops. 1177 */ 1178 unsigned io_plugged; 1179 1180 /* do we need to tell the quest if we have a volatile write cache? */ 1181 int enable_write_cache; 1182 1183 /* Accessed with atomic ops. */ 1184 int quiesce_counter; 1185 1186 unsigned int write_gen; /* Current data generation */ 1187 1188 /* Protected by reqs_lock. */ 1189 CoMutex reqs_lock; 1190 QLIST_HEAD(, BdrvTrackedRequest) tracked_requests; 1191 CoQueue flush_queue; /* Serializing flush queue */ 1192 bool active_flush_req; /* Flush request in flight? */ 1193 1194 /* Only read/written by whoever has set active_flush_req to true. */ 1195 unsigned int flushed_gen; /* Flushed write generation */ 1196 1197 /* BdrvChild links to this node may never be frozen */ 1198 bool never_freeze; 1199 1200 /* Lock for block-status cache RCU writers */ 1201 CoMutex bsc_modify_lock; 1202 /* Always non-NULL, but must only be dereferenced under an RCU read guard */ 1203 BdrvBlockStatusCache *block_status_cache; 1204 }; 1205 1206 struct BlockBackendRootState { 1207 int open_flags; 1208 BlockdevDetectZeroesOptions detect_zeroes; 1209 }; 1210 1211 typedef enum BlockMirrorBackingMode { 1212 /* 1213 * Reuse the existing backing chain from the source for the target. 1214 * - sync=full: Set backing BDS to NULL. 1215 * - sync=top: Use source's backing BDS. 1216 * - sync=none: Use source as the backing BDS. 1217 */ 1218 MIRROR_SOURCE_BACKING_CHAIN, 1219 1220 /* Open the target's backing chain completely anew */ 1221 MIRROR_OPEN_BACKING_CHAIN, 1222 1223 /* Do not change the target's backing BDS after job completion */ 1224 MIRROR_LEAVE_BACKING_CHAIN, 1225 } BlockMirrorBackingMode; 1226 1227 1228 /* 1229 * Essential block drivers which must always be statically linked into qemu, and 1230 * which therefore can be accessed without using bdrv_find_format() 1231 */ 1232 extern BlockDriver bdrv_file; 1233 extern BlockDriver bdrv_raw; 1234 extern BlockDriver bdrv_qcow2; 1235 1236 extern unsigned int bdrv_drain_all_count; 1237 extern QemuOptsList bdrv_create_opts_simple; 1238 1239 /* 1240 * Common functions that are neither I/O nor Global State. 1241 * 1242 * See include/block/block-commmon.h for more information about 1243 * the Common API. 1244 */ 1245 1246 static inline BlockDriverState *child_bs(BdrvChild *child) 1247 { 1248 return child ? child->bs : NULL; 1249 } 1250 1251 int bdrv_check_request(int64_t offset, int64_t bytes, Error **errp); 1252 char *create_tmp_file(Error **errp); 1253 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, 1254 QDict *options); 1255 1256 1257 int bdrv_check_qiov_request(int64_t offset, int64_t bytes, 1258 QEMUIOVector *qiov, size_t qiov_offset, 1259 Error **errp); 1260 1261 #ifdef _WIN32 1262 int is_windows_drive(const char *filename); 1263 #endif 1264 1265 #endif /* BLOCK_INT_COMMON_H */ 1266