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 * Set to true if the BlockDriver supports zoned children. 142 */ 143 bool supports_zoned_children; 144 145 /* 146 * Drivers not implementing bdrv_parse_filename nor bdrv_open should have 147 * this field set to true, except ones that are defined only by their 148 * child's bs. 149 * An example of the last type will be the quorum block driver. 150 */ 151 bool bdrv_needs_filename; 152 153 /* 154 * Set if a driver can support backing files. This also implies the 155 * following semantics: 156 * 157 * - Return status 0 of .bdrv_co_block_status means that corresponding 158 * blocks are not allocated in this layer of backing-chain 159 * - For such (unallocated) blocks, read will: 160 * - fill buffer with zeros if there is no backing file 161 * - read from the backing file otherwise, where the block layer 162 * takes care of reading zeros beyond EOF if backing file is short 163 */ 164 bool supports_backing; 165 166 /* 167 * Drivers setting this field must be able to work with just a plain 168 * filename with '<protocol_name>:' as a prefix, and no other options. 169 * Options may be extracted from the filename by implementing 170 * bdrv_parse_filename. 171 */ 172 const char *protocol_name; 173 174 /* List of options for creating images, terminated by name == NULL */ 175 QemuOptsList *create_opts; 176 177 /* List of options for image amend */ 178 QemuOptsList *amend_opts; 179 180 /* 181 * If this driver supports reopening images this contains a 182 * NULL-terminated list of the runtime options that can be 183 * modified. If an option in this list is unspecified during 184 * reopen then it _must_ be reset to its default value or return 185 * an error. 186 */ 187 const char *const *mutable_opts; 188 189 /* 190 * Pointer to a NULL-terminated array of names of strong options 191 * that can be specified for bdrv_open(). A strong option is one 192 * that changes the data of a BDS. 193 * If this pointer is NULL, the array is considered empty. 194 * "filename" and "driver" are always considered strong. 195 */ 196 const char *const *strong_runtime_opts; 197 198 199 /* 200 * Global state (GS) API. These functions run under the BQL. 201 * 202 * See include/block/block-global-state.h for more information about 203 * the GS API. 204 */ 205 206 /* 207 * This function is invoked under BQL before .bdrv_co_amend() 208 * (which in contrast does not necessarily run under the BQL) 209 * to allow driver-specific initialization code that requires 210 * the BQL, like setting up specific permission flags. 211 */ 212 int GRAPH_RDLOCK_PTR (*bdrv_amend_pre_run)( 213 BlockDriverState *bs, Error **errp); 214 /* 215 * This function is invoked under BQL after .bdrv_co_amend() 216 * to allow cleaning up what was done in .bdrv_amend_pre_run(). 217 */ 218 void GRAPH_RDLOCK_PTR (*bdrv_amend_clean)(BlockDriverState *bs); 219 220 /* 221 * Return true if @to_replace can be replaced by a BDS with the 222 * same data as @bs without it affecting @bs's behavior (that is, 223 * without it being visible to @bs's parents). 224 */ 225 bool GRAPH_RDLOCK_PTR (*bdrv_recurse_can_replace)( 226 BlockDriverState *bs, BlockDriverState *to_replace); 227 228 int (*bdrv_probe_device)(const char *filename); 229 230 /* 231 * Any driver implementing this callback is expected to be able to handle 232 * NULL file names in its .bdrv_open() implementation. 233 */ 234 void (*bdrv_parse_filename)(const char *filename, QDict *options, 235 Error **errp); 236 237 /* For handling image reopen for split or non-split files. */ 238 int (*bdrv_reopen_prepare)(BDRVReopenState *reopen_state, 239 BlockReopenQueue *queue, Error **errp); 240 void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state); 241 void (*bdrv_reopen_commit_post)(BDRVReopenState *reopen_state); 242 void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state); 243 void (*bdrv_join_options)(QDict *options, QDict *old_options); 244 245 int GRAPH_UNLOCKED_PTR (*bdrv_open)( 246 BlockDriverState *bs, QDict *options, int flags, Error **errp); 247 248 /* Protocol drivers should implement this instead of bdrv_open */ 249 int GRAPH_UNLOCKED_PTR (*bdrv_file_open)( 250 BlockDriverState *bs, QDict *options, int flags, Error **errp); 251 void (*bdrv_close)(BlockDriverState *bs); 252 253 int coroutine_fn GRAPH_UNLOCKED_PTR (*bdrv_co_create)( 254 BlockdevCreateOptions *opts, Error **errp); 255 256 int coroutine_fn GRAPH_UNLOCKED_PTR (*bdrv_co_create_opts)( 257 BlockDriver *drv, const char *filename, QemuOpts *opts, Error **errp); 258 259 int (*bdrv_amend_options)(BlockDriverState *bs, 260 QemuOpts *opts, 261 BlockDriverAmendStatusCB *status_cb, 262 void *cb_opaque, 263 bool force, 264 Error **errp); 265 266 int (*bdrv_make_empty)(BlockDriverState *bs); 267 268 /* 269 * Refreshes the bs->exact_filename field. If that is impossible, 270 * bs->exact_filename has to be left empty. 271 */ 272 void (*bdrv_refresh_filename)(BlockDriverState *bs); 273 274 /* 275 * Gathers the open options for all children into @target. 276 * A simple format driver (without backing file support) might 277 * implement this function like this: 278 * 279 * QINCREF(bs->file->bs->full_open_options); 280 * qdict_put(target, "file", bs->file->bs->full_open_options); 281 * 282 * If not specified, the generic implementation will simply put 283 * all children's options under their respective name. 284 * 285 * @backing_overridden is true when bs->backing seems not to be 286 * the child that would result from opening bs->backing_file. 287 * Therefore, if it is true, the backing child's options should be 288 * gathered; otherwise, there is no need since the backing child 289 * is the one implied by the image header. 290 * 291 * Note that ideally this function would not be needed. Every 292 * block driver which implements it is probably doing something 293 * shady regarding its runtime option structure. 294 */ 295 void (*bdrv_gather_child_options)(BlockDriverState *bs, QDict *target, 296 bool backing_overridden); 297 298 /* 299 * Returns an allocated string which is the directory name of this BDS: It 300 * will be used to make relative filenames absolute by prepending this 301 * function's return value to them. 302 */ 303 char *(*bdrv_dirname)(BlockDriverState *bs, Error **errp); 304 305 /* 306 * This informs the driver that we are no longer interested in the result 307 * of in-flight requests, so don't waste the time if possible. 308 * 309 * One example usage is to avoid waiting for an nbd target node reconnect 310 * timeout during job-cancel with force=true. 311 */ 312 void (*bdrv_cancel_in_flight)(BlockDriverState *bs); 313 314 int GRAPH_RDLOCK_PTR (*bdrv_inactivate)(BlockDriverState *bs); 315 316 int (*bdrv_snapshot_create)(BlockDriverState *bs, 317 QEMUSnapshotInfo *sn_info); 318 int (*bdrv_snapshot_goto)(BlockDriverState *bs, 319 const char *snapshot_id); 320 int (*bdrv_snapshot_delete)(BlockDriverState *bs, 321 const char *snapshot_id, 322 const char *name, 323 Error **errp); 324 int (*bdrv_snapshot_list)(BlockDriverState *bs, 325 QEMUSnapshotInfo **psn_info); 326 int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs, 327 const char *snapshot_id, 328 const char *name, 329 Error **errp); 330 331 int (*bdrv_change_backing_file)(BlockDriverState *bs, 332 const char *backing_file, const char *backing_fmt); 333 334 /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */ 335 int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event, 336 const char *tag); 337 int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs, 338 const char *tag); 339 int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag); 340 bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag); 341 342 void GRAPH_RDLOCK_PTR (*bdrv_refresh_limits)( 343 BlockDriverState *bs, Error **errp); 344 345 /* 346 * Returns 1 if newly created images are guaranteed to contain only 347 * zeros, 0 otherwise. 348 */ 349 int (*bdrv_has_zero_init)(BlockDriverState *bs); 350 351 /* 352 * Remove fd handlers, timers, and other event loop callbacks so the event 353 * loop is no longer in use. Called with no in-flight requests and in 354 * depth-first traversal order with parents before child nodes. 355 */ 356 void (*bdrv_detach_aio_context)(BlockDriverState *bs); 357 358 /* 359 * Add fd handlers, timers, and other event loop callbacks so I/O requests 360 * can be processed again. Called with no in-flight requests and in 361 * depth-first traversal order with child nodes before parent nodes. 362 */ 363 void (*bdrv_attach_aio_context)(BlockDriverState *bs, 364 AioContext *new_context); 365 366 /** 367 * bdrv_drain_begin is called if implemented in the beginning of a 368 * drain operation to drain and stop any internal sources of requests in 369 * the driver. 370 * bdrv_drain_end is called if implemented at the end of the drain. 371 * 372 * They should be used by the driver to e.g. manage scheduled I/O 373 * requests, or toggle an internal state. After the end of the drain new 374 * requests will continue normally. 375 * 376 * Implementations of both functions must not call aio_poll(). 377 */ 378 void (*bdrv_drain_begin)(BlockDriverState *bs); 379 void (*bdrv_drain_end)(BlockDriverState *bs); 380 381 /** 382 * Try to get @bs's logical and physical block size. 383 * On success, store them in @bsz and return zero. 384 * On failure, return negative errno. 385 */ 386 int (*bdrv_probe_blocksizes)(BlockDriverState *bs, BlockSizes *bsz); 387 /** 388 * Try to get @bs's geometry (cyls, heads, sectors) 389 * On success, store them in @geo and return 0. 390 * On failure return -errno. 391 * Only drivers that want to override guest geometry implement this 392 * callback; see hd_geometry_guess(). 393 */ 394 int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo); 395 396 void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child, 397 Error **errp); 398 void (*bdrv_del_child)(BlockDriverState *parent, BdrvChild *child, 399 Error **errp); 400 401 /** 402 * Informs the block driver that a permission change is intended. The 403 * driver checks whether the change is permissible and may take other 404 * preparations for the change (e.g. get file system locks). This operation 405 * is always followed either by a call to either .bdrv_set_perm or 406 * .bdrv_abort_perm_update. 407 * 408 * Checks whether the requested set of cumulative permissions in @perm 409 * can be granted for accessing @bs and whether no other users are using 410 * permissions other than those given in @shared (both arguments take 411 * BLK_PERM_* bitmasks). 412 * 413 * If both conditions are met, 0 is returned. Otherwise, -errno is returned 414 * and errp is set to an error describing the conflict. 415 */ 416 int GRAPH_RDLOCK_PTR (*bdrv_check_perm)(BlockDriverState *bs, uint64_t perm, 417 uint64_t shared, Error **errp); 418 419 /** 420 * Called to inform the driver that the set of cumulative set of used 421 * permissions for @bs has changed to @perm, and the set of shareable 422 * permission to @shared. The driver can use this to propagate changes to 423 * its children (i.e. request permissions only if a parent actually needs 424 * them). 425 * 426 * This function is only invoked after bdrv_check_perm(), so block drivers 427 * may rely on preparations made in their .bdrv_check_perm implementation. 428 */ 429 void GRAPH_RDLOCK_PTR (*bdrv_set_perm)( 430 BlockDriverState *bs, uint64_t perm, uint64_t shared); 431 432 /* 433 * Called to inform the driver that after a previous bdrv_check_perm() 434 * call, the permission update is not performed and any preparations made 435 * for it (e.g. taken file locks) need to be undone. 436 * 437 * This function can be called even for nodes that never saw a 438 * bdrv_check_perm() call. It is a no-op then. 439 */ 440 void GRAPH_RDLOCK_PTR (*bdrv_abort_perm_update)(BlockDriverState *bs); 441 442 /** 443 * Returns in @nperm and @nshared the permissions that the driver for @bs 444 * needs on its child @c, based on the cumulative permissions requested by 445 * the parents in @parent_perm and @parent_shared. 446 * 447 * If @c is NULL, return the permissions for attaching a new child for the 448 * given @child_class and @role. 449 * 450 * If @reopen_queue is non-NULL, don't return the currently needed 451 * permissions, but those that will be needed after applying the 452 * @reopen_queue. 453 */ 454 void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c, 455 BdrvChildRole role, 456 BlockReopenQueue *reopen_queue, 457 uint64_t parent_perm, uint64_t parent_shared, 458 uint64_t *nperm, uint64_t *nshared); 459 460 /** 461 * Register/unregister a buffer for I/O. For example, when the driver is 462 * interested to know the memory areas that will later be used in iovs, so 463 * that it can do IOMMU mapping with VFIO etc., in order to get better 464 * performance. In the case of VFIO drivers, this callback is used to do 465 * DMA mapping for hot buffers. 466 * 467 * Returns: true on success, false on failure 468 */ 469 bool GRAPH_RDLOCK_PTR (*bdrv_register_buf)( 470 BlockDriverState *bs, void *host, size_t size, Error **errp); 471 void GRAPH_RDLOCK_PTR (*bdrv_unregister_buf)( 472 BlockDriverState *bs, void *host, size_t size); 473 474 /* 475 * This field is modified only under the BQL, and is part of 476 * the global state. 477 */ 478 QLIST_ENTRY(BlockDriver) list; 479 480 /* 481 * I/O API functions. These functions are thread-safe. 482 * 483 * See include/block/block-io.h for more information about 484 * the I/O API. 485 */ 486 487 int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename); 488 489 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_amend)( 490 BlockDriverState *bs, BlockdevAmendOptions *opts, bool force, 491 Error **errp); 492 493 /* aio */ 494 BlockAIOCB * GRAPH_RDLOCK_PTR (*bdrv_aio_preadv)(BlockDriverState *bs, 495 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 496 BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); 497 498 BlockAIOCB * GRAPH_RDLOCK_PTR (*bdrv_aio_pwritev)(BlockDriverState *bs, 499 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 500 BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); 501 502 BlockAIOCB * GRAPH_RDLOCK_PTR (*bdrv_aio_flush)( 503 BlockDriverState *bs, BlockCompletionFunc *cb, void *opaque); 504 505 BlockAIOCB * GRAPH_RDLOCK_PTR (*bdrv_aio_pdiscard)( 506 BlockDriverState *bs, int64_t offset, int bytes, 507 BlockCompletionFunc *cb, void *opaque); 508 509 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_readv)(BlockDriverState *bs, 510 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); 511 512 /** 513 * @offset: position in bytes to read at 514 * @bytes: number of bytes to read 515 * @qiov: the buffers to fill with read data 516 * @flags: currently unused, always 0 517 * 518 * @offset and @bytes will be a multiple of 'request_alignment', 519 * but the length of individual @qiov elements does not have to 520 * be a multiple. 521 * 522 * @bytes will always equal the total size of @qiov, and will be 523 * no larger than 'max_transfer'. 524 * 525 * The buffer in @qiov may point directly to guest memory. 526 */ 527 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_preadv)(BlockDriverState *bs, 528 int64_t offset, int64_t bytes, QEMUIOVector *qiov, 529 BdrvRequestFlags flags); 530 531 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_preadv_part)( 532 BlockDriverState *bs, int64_t offset, int64_t bytes, 533 QEMUIOVector *qiov, size_t qiov_offset, 534 BdrvRequestFlags flags); 535 536 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_writev)(BlockDriverState *bs, 537 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, 538 int flags); 539 /** 540 * @offset: position in bytes to write at 541 * @bytes: number of bytes to write 542 * @qiov: the buffers containing data to write 543 * @flags: zero or more bits allowed by 'supported_write_flags' 544 * 545 * @offset and @bytes will be a multiple of 'request_alignment', 546 * but the length of individual @qiov elements does not have to 547 * be a multiple. 548 * 549 * @bytes will always equal the total size of @qiov, and will be 550 * no larger than 'max_transfer'. 551 * 552 * The buffer in @qiov may point directly to guest memory. 553 */ 554 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pwritev)( 555 BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov, 556 BdrvRequestFlags flags); 557 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pwritev_part)( 558 BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov, 559 size_t qiov_offset, BdrvRequestFlags flags); 560 561 /* 562 * Efficiently zero a region of the disk image. Typically an image format 563 * would use a compact metadata representation to implement this. This 564 * function pointer may be NULL or return -ENOSUP and .bdrv_co_writev() 565 * will be called instead. 566 */ 567 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pwrite_zeroes)( 568 BlockDriverState *bs, int64_t offset, int64_t bytes, 569 BdrvRequestFlags flags); 570 571 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pdiscard)( 572 BlockDriverState *bs, int64_t offset, int64_t bytes); 573 574 /* 575 * Map [offset, offset + nbytes) range onto a child of @bs to copy from, 576 * and invoke bdrv_co_copy_range_from(child, ...), or invoke 577 * bdrv_co_copy_range_to() if @bs is the leaf child to copy data from. 578 * 579 * See the comment of bdrv_co_copy_range for the parameter and return value 580 * semantics. 581 */ 582 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_copy_range_from)( 583 BlockDriverState *bs, BdrvChild *src, int64_t offset, 584 BdrvChild *dst, int64_t dst_offset, int64_t bytes, 585 BdrvRequestFlags read_flags, BdrvRequestFlags write_flags); 586 587 /* 588 * Map [offset, offset + nbytes) range onto a child of bs to copy data to, 589 * and invoke bdrv_co_copy_range_to(child, src, ...), or perform the copy 590 * operation if @bs is the leaf and @src has the same BlockDriver. Return 591 * -ENOTSUP if @bs is the leaf but @src has a different BlockDriver. 592 * 593 * See the comment of bdrv_co_copy_range for the parameter and return value 594 * semantics. 595 */ 596 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_copy_range_to)( 597 BlockDriverState *bs, BdrvChild *src, int64_t src_offset, 598 BdrvChild *dst, int64_t dst_offset, int64_t bytes, 599 BdrvRequestFlags read_flags, BdrvRequestFlags write_flags); 600 601 /* 602 * Building block for bdrv_block_status[_above] and 603 * bdrv_is_allocated[_above]. The driver should answer only 604 * according to the current layer, and should only need to set 605 * BDRV_BLOCK_DATA, BDRV_BLOCK_ZERO, BDRV_BLOCK_OFFSET_VALID, 606 * and/or BDRV_BLOCK_RAW; if the current layer defers to a backing 607 * layer, the result should be 0 (and not BDRV_BLOCK_ZERO). See 608 * block.h for the overall meaning of the bits. As a hint, the 609 * flag want_zero is true if the caller cares more about precise 610 * mappings (favor accurate _OFFSET_VALID/_ZERO) or false for 611 * overall allocation (favor larger *pnum, perhaps by reporting 612 * _DATA instead of _ZERO). The block layer guarantees input 613 * clamped to bdrv_getlength() and aligned to request_alignment, 614 * as well as non-NULL pnum, map, and file; in turn, the driver 615 * must return an error or set pnum to an aligned non-zero value. 616 * 617 * Note that @bytes is just a hint on how big of a region the 618 * caller wants to inspect. It is not a limit on *pnum. 619 * Implementations are free to return larger values of *pnum if 620 * doing so does not incur a performance penalty. 621 * 622 * block/io.c's bdrv_co_block_status() will utilize an unclamped 623 * *pnum value for the block-status cache on protocol nodes, prior 624 * to clamping *pnum for return to its caller. 625 */ 626 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_block_status)( 627 BlockDriverState *bs, 628 bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum, 629 int64_t *map, BlockDriverState **file); 630 631 /* 632 * Snapshot-access API. 633 * 634 * Block-driver may provide snapshot-access API: special functions to access 635 * some internal "snapshot". The functions are similar with normal 636 * read/block_status/discard handler, but don't have any specific handling 637 * in generic block-layer: no serializing, no alignment, no tracked 638 * requests. So, block-driver that realizes these APIs is fully responsible 639 * for synchronization between snapshot-access API and normal IO requests. 640 * 641 * TODO: To be able to support qcow2's internal snapshots, this API will 642 * need to be extended to: 643 * - be able to select a specific snapshot 644 * - receive the snapshot's actual length (which may differ from bs's 645 * length) 646 */ 647 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_preadv_snapshot)( 648 BlockDriverState *bs, int64_t offset, int64_t bytes, 649 QEMUIOVector *qiov, size_t qiov_offset); 650 651 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_snapshot_block_status)( 652 BlockDriverState *bs, bool want_zero, int64_t offset, int64_t bytes, 653 int64_t *pnum, int64_t *map, BlockDriverState **file); 654 655 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pdiscard_snapshot)( 656 BlockDriverState *bs, int64_t offset, int64_t bytes); 657 658 /* 659 * Invalidate any cached meta-data. 660 */ 661 void coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_invalidate_cache)( 662 BlockDriverState *bs, Error **errp); 663 664 /* 665 * Flushes all data for all layers by calling bdrv_co_flush for underlying 666 * layers, if needed. This function is needed for deterministic 667 * synchronization of the flush finishing callback. 668 */ 669 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_flush)(BlockDriverState *bs); 670 671 /* Delete a created file. */ 672 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_delete_file)( 673 BlockDriverState *bs, Error **errp); 674 675 /* 676 * Flushes all data that was already written to the OS all the way down to 677 * the disk (for example file-posix.c calls fsync()). 678 */ 679 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_flush_to_disk)( 680 BlockDriverState *bs); 681 682 /* 683 * Flushes all internal caches to the OS. The data may still sit in a 684 * writeback cache of the host OS, but it will survive a crash of the qemu 685 * process. 686 */ 687 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_flush_to_os)( 688 BlockDriverState *bs); 689 690 /* 691 * Truncate @bs to @offset bytes using the given @prealloc mode 692 * when growing. Modes other than PREALLOC_MODE_OFF should be 693 * rejected when shrinking @bs. 694 * 695 * If @exact is true, @bs must be resized to exactly @offset. 696 * Otherwise, it is sufficient for @bs (if it is a host block 697 * device and thus there is no way to resize it) to be at least 698 * @offset bytes in length. 699 * 700 * If @exact is true and this function fails but would succeed 701 * with @exact = false, it should return -ENOTSUP. 702 */ 703 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_truncate)( 704 BlockDriverState *bs, int64_t offset, bool exact, 705 PreallocMode prealloc, BdrvRequestFlags flags, Error **errp); 706 707 int64_t coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_getlength)( 708 BlockDriverState *bs); 709 710 int64_t coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_get_allocated_file_size)( 711 BlockDriverState *bs); 712 713 BlockMeasureInfo *(*bdrv_measure)(QemuOpts *opts, BlockDriverState *in_bs, 714 Error **errp); 715 716 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pwritev_compressed)( 717 BlockDriverState *bs, int64_t offset, int64_t bytes, 718 QEMUIOVector *qiov); 719 720 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pwritev_compressed_part)( 721 BlockDriverState *bs, int64_t offset, int64_t bytes, 722 QEMUIOVector *qiov, size_t qiov_offset); 723 724 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_get_info)( 725 BlockDriverState *bs, BlockDriverInfo *bdi); 726 727 ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs, 728 Error **errp); 729 BlockStatsSpecific *(*bdrv_get_specific_stats)(BlockDriverState *bs); 730 731 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_save_vmstate)( 732 BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); 733 734 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_load_vmstate)( 735 BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); 736 737 int coroutine_fn (*bdrv_co_zone_report)(BlockDriverState *bs, 738 int64_t offset, unsigned int *nr_zones, 739 BlockZoneDescriptor *zones); 740 int coroutine_fn (*bdrv_co_zone_mgmt)(BlockDriverState *bs, BlockZoneOp op, 741 int64_t offset, int64_t len); 742 int coroutine_fn (*bdrv_co_zone_append)(BlockDriverState *bs, 743 int64_t *offset, QEMUIOVector *qiov, 744 BdrvRequestFlags flags); 745 746 /* removable device specific */ 747 bool coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_is_inserted)( 748 BlockDriverState *bs); 749 void coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_eject)( 750 BlockDriverState *bs, bool eject_flag); 751 void coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_lock_medium)( 752 BlockDriverState *bs, bool locked); 753 754 /* to control generic scsi devices */ 755 BlockAIOCB *coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_aio_ioctl)( 756 BlockDriverState *bs, unsigned long int req, void *buf, 757 BlockCompletionFunc *cb, void *opaque); 758 759 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_ioctl)( 760 BlockDriverState *bs, unsigned long int req, void *buf); 761 762 /* 763 * Returns 0 for completed check, -errno for internal errors. 764 * The check results are stored in result. 765 */ 766 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_check)( 767 BlockDriverState *bs, BdrvCheckResult *result, BdrvCheckMode fix); 768 769 void coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_debug_event)( 770 BlockDriverState *bs, BlkdebugEvent event); 771 772 bool (*bdrv_supports_persistent_dirty_bitmap)(BlockDriverState *bs); 773 774 bool coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_can_store_new_dirty_bitmap)( 775 BlockDriverState *bs, const char *name, uint32_t granularity, 776 Error **errp); 777 778 int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_remove_persistent_dirty_bitmap)( 779 BlockDriverState *bs, const char *name, Error **errp); 780 }; 781 782 static inline bool TSA_NO_TSA block_driver_can_compress(BlockDriver *drv) 783 { 784 return drv->bdrv_co_pwritev_compressed || 785 drv->bdrv_co_pwritev_compressed_part; 786 } 787 788 typedef struct BlockLimits { 789 /* 790 * Alignment requirement, in bytes, for offset/length of I/O 791 * requests. Must be a power of 2 less than INT_MAX; defaults to 792 * 1 for drivers with modern byte interfaces, and to 512 793 * otherwise. 794 */ 795 uint32_t request_alignment; 796 797 /* 798 * Maximum number of bytes that can be discarded at once. Must be multiple 799 * of pdiscard_alignment, but need not be power of 2. May be 0 if no 800 * inherent 64-bit limit. 801 */ 802 int64_t max_pdiscard; 803 804 /* 805 * Optimal alignment for discard requests in bytes. A power of 2 806 * is best but not mandatory. Must be a multiple of 807 * bl.request_alignment, and must be less than max_pdiscard if 808 * that is set. May be 0 if bl.request_alignment is good enough 809 */ 810 uint32_t pdiscard_alignment; 811 812 /* 813 * Maximum number of bytes that can zeroized at once. Must be multiple of 814 * pwrite_zeroes_alignment. 0 means no limit. 815 */ 816 int64_t max_pwrite_zeroes; 817 818 /* 819 * Optimal alignment for write zeroes requests in bytes. A power 820 * of 2 is best but not mandatory. Must be a multiple of 821 * bl.request_alignment, and must be less than max_pwrite_zeroes 822 * if that is set. May be 0 if bl.request_alignment is good 823 * enough 824 */ 825 uint32_t pwrite_zeroes_alignment; 826 827 /* 828 * Optimal transfer length in bytes. A power of 2 is best but not 829 * mandatory. Must be a multiple of bl.request_alignment, or 0 if 830 * no preferred size 831 */ 832 uint32_t opt_transfer; 833 834 /* 835 * Maximal transfer length in bytes. Need not be power of 2, but 836 * must be multiple of opt_transfer and bl.request_alignment, or 0 837 * for no 32-bit limit. For now, anything larger than INT_MAX is 838 * clamped down. 839 */ 840 uint32_t max_transfer; 841 842 /* 843 * Maximal hardware transfer length in bytes. Applies whenever 844 * transfers to the device bypass the kernel I/O scheduler, for 845 * example with SG_IO. If larger than max_transfer or if zero, 846 * blk_get_max_hw_transfer will fall back to max_transfer. 847 */ 848 uint64_t max_hw_transfer; 849 850 /* 851 * Maximal number of scatter/gather elements allowed by the hardware. 852 * Applies whenever transfers to the device bypass the kernel I/O 853 * scheduler, for example with SG_IO. If larger than max_iov 854 * or if zero, blk_get_max_hw_iov will fall back to max_iov. 855 */ 856 int max_hw_iov; 857 858 859 /* memory alignment, in bytes so that no bounce buffer is needed */ 860 size_t min_mem_alignment; 861 862 /* memory alignment, in bytes, for bounce buffer */ 863 size_t opt_mem_alignment; 864 865 /* maximum number of iovec elements */ 866 int max_iov; 867 868 /* 869 * true if the length of the underlying file can change, and QEMU 870 * is expected to adjust automatically. Mostly for CD-ROM drives, 871 * whose length is zero when the tray is empty (they don't need 872 * an explicit monitor command to load the disk inside the guest). 873 */ 874 bool has_variable_length; 875 876 /* device zone model */ 877 BlockZoneModel zoned; 878 879 /* zone size expressed in bytes */ 880 uint32_t zone_size; 881 882 /* total number of zones */ 883 uint32_t nr_zones; 884 885 /* maximum sectors of a zone append write operation */ 886 uint32_t max_append_sectors; 887 888 /* maximum number of open zones */ 889 uint32_t max_open_zones; 890 891 /* maximum number of active zones */ 892 uint32_t max_active_zones; 893 894 uint32_t write_granularity; 895 } BlockLimits; 896 897 typedef struct BdrvOpBlocker BdrvOpBlocker; 898 899 typedef struct BdrvAioNotifier { 900 void (*attached_aio_context)(AioContext *new_context, void *opaque); 901 void (*detach_aio_context)(void *opaque); 902 903 void *opaque; 904 bool deleted; 905 906 QLIST_ENTRY(BdrvAioNotifier) list; 907 } BdrvAioNotifier; 908 909 struct BdrvChildClass { 910 /* 911 * If true, bdrv_replace_node() doesn't change the node this BdrvChild 912 * points to. 913 */ 914 bool stay_at_node; 915 916 /* 917 * If true, the parent is a BlockDriverState and bdrv_next_all_states() 918 * will return it. This information is used for drain_all, where every node 919 * will be drained separately, so the drain only needs to be propagated to 920 * non-BDS parents. 921 */ 922 bool parent_is_bds; 923 924 /* 925 * Global state (GS) API. These functions run under the BQL. 926 * 927 * See include/block/block-global-state.h for more information about 928 * the GS API. 929 */ 930 void (*inherit_options)(BdrvChildRole role, bool parent_is_format, 931 int *child_flags, QDict *child_options, 932 int parent_flags, QDict *parent_options); 933 void (*change_media)(BdrvChild *child, bool load); 934 935 /* 936 * Returns a malloced string that describes the parent of the child for a 937 * human reader. This could be a node-name, BlockBackend name, qdev ID or 938 * QOM path of the device owning the BlockBackend, job type and ID etc. The 939 * caller is responsible for freeing the memory. 940 */ 941 char *(*get_parent_desc)(BdrvChild *child); 942 943 /* 944 * Notifies the parent that the child has been activated/inactivated (e.g. 945 * when migration is completing) and it can start/stop requesting 946 * permissions and doing I/O on it. 947 */ 948 void GRAPH_RDLOCK_PTR (*activate)(BdrvChild *child, Error **errp); 949 int GRAPH_RDLOCK_PTR (*inactivate)(BdrvChild *child); 950 951 void GRAPH_WRLOCK_PTR (*attach)(BdrvChild *child); 952 void GRAPH_WRLOCK_PTR (*detach)(BdrvChild *child); 953 954 /* 955 * If this pair of functions is implemented, the parent doesn't issue new 956 * requests after returning from .drained_begin() until .drained_end() is 957 * called. 958 * 959 * These functions must not change the graph (and therefore also must not 960 * call aio_poll(), which could change the graph indirectly). 961 * 962 * Note that this can be nested. If drained_begin() was called twice, new 963 * I/O is allowed only after drained_end() was called twice, too. 964 */ 965 void (*drained_begin)(BdrvChild *child); 966 void (*drained_end)(BdrvChild *child); 967 968 /* 969 * Returns whether the parent has pending requests for the child. This 970 * callback is polled after .drained_begin() has been called until all 971 * activity on the child has stopped. 972 */ 973 bool (*drained_poll)(BdrvChild *child); 974 975 /* 976 * Notifies the parent that the filename of its child has changed (e.g. 977 * because the direct child was removed from the backing chain), so that it 978 * can update its reference. 979 */ 980 int (*update_filename)(BdrvChild *child, BlockDriverState *new_base, 981 const char *filename, Error **errp); 982 983 bool (*change_aio_ctx)(BdrvChild *child, AioContext *ctx, 984 GHashTable *visited, Transaction *tran, 985 Error **errp); 986 987 /* 988 * I/O API functions. These functions are thread-safe. 989 * 990 * See include/block/block-io.h for more information about 991 * the I/O API. 992 */ 993 994 void (*resize)(BdrvChild *child); 995 996 /* 997 * Returns a name that is supposedly more useful for human users than the 998 * node name for identifying the node in question (in particular, a BB 999 * name), or NULL if the parent can't provide a better name. 1000 */ 1001 const char *(*get_name)(BdrvChild *child); 1002 1003 AioContext *(*get_parent_aio_context)(BdrvChild *child); 1004 }; 1005 1006 extern const BdrvChildClass child_of_bds; 1007 1008 struct BdrvChild { 1009 BlockDriverState *bs; 1010 char *name; 1011 const BdrvChildClass *klass; 1012 BdrvChildRole role; 1013 void *opaque; 1014 1015 /** 1016 * Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask) 1017 */ 1018 uint64_t perm; 1019 1020 /** 1021 * Permissions that can still be granted to other users of @bs while this 1022 * BdrvChild is still attached to it. (BLK_PERM_* bitmask) 1023 */ 1024 uint64_t shared_perm; 1025 1026 /* 1027 * This link is frozen: the child can neither be replaced nor 1028 * detached from the parent. 1029 */ 1030 bool frozen; 1031 1032 /* 1033 * True if the parent of this child has been drained by this BdrvChild 1034 * (through klass->drained_*). 1035 * 1036 * It is generally true if bs->quiesce_counter > 0. It may differ while the 1037 * child is entering or leaving a drained section. 1038 */ 1039 bool quiesced_parent; 1040 1041 QLIST_ENTRY(BdrvChild) next; 1042 QLIST_ENTRY(BdrvChild) next_parent; 1043 }; 1044 1045 /* 1046 * Allows bdrv_co_block_status() to cache one data region for a 1047 * protocol node. 1048 * 1049 * @valid: Whether the cache is valid (should be accessed with atomic 1050 * functions so this can be reset by RCU readers) 1051 * @data_start: Offset where we know (or strongly assume) is data 1052 * @data_end: Offset where the data region ends (which is not necessarily 1053 * the start of a zeroed region) 1054 */ 1055 typedef struct BdrvBlockStatusCache { 1056 struct rcu_head rcu; 1057 1058 bool valid; 1059 int64_t data_start; 1060 int64_t data_end; 1061 } BdrvBlockStatusCache; 1062 1063 struct BlockDriverState { 1064 /* 1065 * Protected by big QEMU lock or read-only after opening. No special 1066 * locking needed during I/O... 1067 */ 1068 int open_flags; /* flags used to open the file, re-used for re-open */ 1069 bool encrypted; /* if true, the media is encrypted */ 1070 bool sg; /* if true, the device is a /dev/sg* */ 1071 bool probed; /* if true, format was probed rather than specified */ 1072 bool force_share; /* if true, always allow all shared permissions */ 1073 bool implicit; /* if true, this filter node was automatically inserted */ 1074 1075 BlockDriver *drv; /* NULL means no media */ 1076 void *opaque; 1077 1078 AioContext *aio_context; /* event loop used for fd handlers, timers, etc */ 1079 /* 1080 * long-running tasks intended to always use the same AioContext as this 1081 * BDS may register themselves in this list to be notified of changes 1082 * regarding this BDS's context 1083 */ 1084 QLIST_HEAD(, BdrvAioNotifier) aio_notifiers; 1085 bool walking_aio_notifiers; /* to make removal during iteration safe */ 1086 1087 char filename[PATH_MAX]; 1088 /* 1089 * If not empty, this image is a diff in relation to backing_file. 1090 * Note that this is the name given in the image header and 1091 * therefore may or may not be equal to .backing->bs->filename. 1092 * If this field contains a relative path, it is to be resolved 1093 * relatively to the overlay's location. 1094 */ 1095 char backing_file[PATH_MAX]; 1096 /* 1097 * The backing filename indicated by the image header. Contrary 1098 * to backing_file, if we ever open this file, auto_backing_file 1099 * is replaced by the resulting BDS's filename (i.e. after a 1100 * bdrv_refresh_filename() run). 1101 */ 1102 char auto_backing_file[PATH_MAX]; 1103 char backing_format[16]; /* if non-zero and backing_file exists */ 1104 1105 QDict *full_open_options; 1106 char exact_filename[PATH_MAX]; 1107 1108 /* I/O Limits */ 1109 BlockLimits bl; 1110 1111 /* 1112 * Flags honored during pread 1113 */ 1114 BdrvRequestFlags supported_read_flags; 1115 /* 1116 * Flags honored during pwrite (so far: BDRV_REQ_FUA, 1117 * BDRV_REQ_WRITE_UNCHANGED). 1118 * If a driver does not support BDRV_REQ_WRITE_UNCHANGED, those 1119 * writes will be issued as normal writes without the flag set. 1120 * This is important to note for drivers that do not explicitly 1121 * request a WRITE permission for their children and instead take 1122 * the same permissions as their parent did (this is commonly what 1123 * block filters do). Such drivers have to be aware that the 1124 * parent may have taken a WRITE_UNCHANGED permission only and is 1125 * issuing such requests. Drivers either must make sure that 1126 * these requests do not result in plain WRITE accesses (usually 1127 * by supporting BDRV_REQ_WRITE_UNCHANGED, and then forwarding 1128 * every incoming write request as-is, including potentially that 1129 * flag), or they have to explicitly take the WRITE permission for 1130 * their children. 1131 */ 1132 BdrvRequestFlags supported_write_flags; 1133 /* 1134 * Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA, 1135 * BDRV_REQ_MAY_UNMAP, BDRV_REQ_WRITE_UNCHANGED) 1136 */ 1137 BdrvRequestFlags supported_zero_flags; 1138 /* 1139 * Flags honoured during truncate (so far: BDRV_REQ_ZERO_WRITE). 1140 * 1141 * If BDRV_REQ_ZERO_WRITE is given, the truncate operation must make sure 1142 * that any added space reads as all zeros. If this can't be guaranteed, 1143 * the operation must fail. 1144 */ 1145 BdrvRequestFlags supported_truncate_flags; 1146 1147 /* the following member gives a name to every node on the bs graph. */ 1148 char node_name[32]; 1149 /* element of the list of named nodes building the graph */ 1150 QTAILQ_ENTRY(BlockDriverState) node_list; 1151 /* element of the list of all BlockDriverStates (all_bdrv_states) */ 1152 QTAILQ_ENTRY(BlockDriverState) bs_list; 1153 /* element of the list of monitor-owned BDS */ 1154 QTAILQ_ENTRY(BlockDriverState) monitor_list; 1155 int refcnt; 1156 1157 /* operation blockers. Protected by BQL. */ 1158 QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; 1159 1160 /* 1161 * The node that this node inherited default options from (and a reopen on 1162 * which can affect this node by changing these defaults). This is always a 1163 * parent node of this node. 1164 */ 1165 BlockDriverState *inherits_from; 1166 1167 /* 1168 * @backing and @file are some of @children or NULL. All these three fields 1169 * (@file, @backing and @children) are modified only in 1170 * bdrv_child_cb_attach() and bdrv_child_cb_detach(). 1171 * 1172 * See also comment in include/block/block.h, to learn how backing and file 1173 * are connected with BdrvChildRole. 1174 */ 1175 QLIST_HEAD(, BdrvChild) children; 1176 BdrvChild *backing; 1177 BdrvChild *file; 1178 1179 QLIST_HEAD(, BdrvChild) parents; 1180 1181 QDict *options; 1182 QDict *explicit_options; 1183 BlockdevDetectZeroesOptions detect_zeroes; 1184 1185 /* The error object in use for blocking operations on backing_hd */ 1186 Error *backing_blocker; 1187 1188 /* Protected by AioContext lock */ 1189 1190 /* 1191 * If we are reading a disk image, give its size in sectors. 1192 * Generally read-only; it is written to by load_snapshot and 1193 * save_snaphost, but the block layer is quiescent during those. 1194 */ 1195 int64_t total_sectors; 1196 1197 /* threshold limit for writes, in bytes. "High water mark". */ 1198 uint64_t write_threshold_offset; 1199 1200 /* 1201 * Writing to the list requires the BQL _and_ the dirty_bitmap_mutex. 1202 * Reading from the list can be done with either the BQL or the 1203 * dirty_bitmap_mutex. Modifying a bitmap only requires 1204 * dirty_bitmap_mutex. 1205 */ 1206 QemuMutex dirty_bitmap_mutex; 1207 QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps; 1208 1209 /* Offset after the highest byte written to */ 1210 Stat64 wr_highest_offset; 1211 1212 /* 1213 * If true, copy read backing sectors into image. Can be >1 if more 1214 * than one client has requested copy-on-read. Accessed with atomic 1215 * ops. 1216 */ 1217 int copy_on_read; 1218 1219 /* 1220 * number of in-flight requests; overall and serialising. 1221 * Accessed with atomic ops. 1222 */ 1223 unsigned int in_flight; 1224 unsigned int serialising_in_flight; 1225 1226 /* do we need to tell the quest if we have a volatile write cache? */ 1227 int enable_write_cache; 1228 1229 /* Accessed with atomic ops. */ 1230 int quiesce_counter; 1231 1232 unsigned int write_gen; /* Current data generation */ 1233 1234 /* Protected by reqs_lock. */ 1235 QemuMutex reqs_lock; 1236 QLIST_HEAD(, BdrvTrackedRequest) tracked_requests; 1237 CoQueue flush_queue; /* Serializing flush queue */ 1238 bool active_flush_req; /* Flush request in flight? */ 1239 1240 /* Only read/written by whoever has set active_flush_req to true. */ 1241 unsigned int flushed_gen; /* Flushed write generation */ 1242 1243 /* BdrvChild links to this node may never be frozen */ 1244 bool never_freeze; 1245 1246 /* Lock for block-status cache RCU writers */ 1247 CoMutex bsc_modify_lock; 1248 /* Always non-NULL, but must only be dereferenced under an RCU read guard */ 1249 BdrvBlockStatusCache *block_status_cache; 1250 1251 /* array of write pointers' location of each zone in the zoned device. */ 1252 BlockZoneWps *wps; 1253 }; 1254 1255 struct BlockBackendRootState { 1256 int open_flags; 1257 BlockdevDetectZeroesOptions detect_zeroes; 1258 }; 1259 1260 typedef enum BlockMirrorBackingMode { 1261 /* 1262 * Reuse the existing backing chain from the source for the target. 1263 * - sync=full: Set backing BDS to NULL. 1264 * - sync=top: Use source's backing BDS. 1265 * - sync=none: Use source as the backing BDS. 1266 */ 1267 MIRROR_SOURCE_BACKING_CHAIN, 1268 1269 /* Open the target's backing chain completely anew */ 1270 MIRROR_OPEN_BACKING_CHAIN, 1271 1272 /* Do not change the target's backing BDS after job completion */ 1273 MIRROR_LEAVE_BACKING_CHAIN, 1274 } BlockMirrorBackingMode; 1275 1276 1277 /* 1278 * Essential block drivers which must always be statically linked into qemu, and 1279 * which therefore can be accessed without using bdrv_find_format() 1280 */ 1281 extern BlockDriver bdrv_file; 1282 extern BlockDriver bdrv_raw; 1283 extern BlockDriver bdrv_qcow2; 1284 1285 extern unsigned int bdrv_drain_all_count; 1286 extern QemuOptsList bdrv_create_opts_simple; 1287 1288 /* 1289 * Common functions that are neither I/O nor Global State. 1290 * 1291 * See include/block/block-common.h for more information about 1292 * the Common API. 1293 */ 1294 1295 static inline BlockDriverState *child_bs(BdrvChild *child) 1296 { 1297 return child ? child->bs : NULL; 1298 } 1299 1300 int bdrv_check_request(int64_t offset, int64_t bytes, Error **errp); 1301 char *create_tmp_file(Error **errp); 1302 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, 1303 QDict *options); 1304 1305 1306 int bdrv_check_qiov_request(int64_t offset, int64_t bytes, 1307 QEMUIOVector *qiov, size_t qiov_offset, 1308 Error **errp); 1309 1310 #ifdef _WIN32 1311 int is_windows_drive(const char *filename); 1312 #endif 1313 1314 #endif /* BLOCK_INT_COMMON_H */ 1315