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