1 /* 2 * QEMU System Emulator block driver 3 * 4 * Copyright (c) 2003 Fabrice Bellard 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 #ifndef BLOCK_INT_H 25 #define BLOCK_INT_H 26 27 #include "block/accounting.h" 28 #include "block/block.h" 29 #include "qemu/option.h" 30 #include "qemu/queue.h" 31 #include "qemu/coroutine.h" 32 #include "qemu/stats64.h" 33 #include "qemu/timer.h" 34 #include "qapi-types.h" 35 #include "qemu/hbitmap.h" 36 #include "block/snapshot.h" 37 #include "qemu/main-loop.h" 38 #include "qemu/throttle.h" 39 40 #define BLOCK_FLAG_LAZY_REFCOUNTS 8 41 42 #define BLOCK_OPT_SIZE "size" 43 #define BLOCK_OPT_ENCRYPT "encryption" 44 #define BLOCK_OPT_ENCRYPT_FORMAT "encrypt.format" 45 #define BLOCK_OPT_COMPAT6 "compat6" 46 #define BLOCK_OPT_HWVERSION "hwversion" 47 #define BLOCK_OPT_BACKING_FILE "backing_file" 48 #define BLOCK_OPT_BACKING_FMT "backing_fmt" 49 #define BLOCK_OPT_CLUSTER_SIZE "cluster_size" 50 #define BLOCK_OPT_TABLE_SIZE "table_size" 51 #define BLOCK_OPT_PREALLOC "preallocation" 52 #define BLOCK_OPT_SUBFMT "subformat" 53 #define BLOCK_OPT_COMPAT_LEVEL "compat" 54 #define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts" 55 #define BLOCK_OPT_ADAPTER_TYPE "adapter_type" 56 #define BLOCK_OPT_REDUNDANCY "redundancy" 57 #define BLOCK_OPT_NOCOW "nocow" 58 #define BLOCK_OPT_OBJECT_SIZE "object_size" 59 #define BLOCK_OPT_REFCOUNT_BITS "refcount_bits" 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 }; 68 69 typedef struct BdrvTrackedRequest { 70 BlockDriverState *bs; 71 int64_t offset; 72 unsigned int bytes; 73 enum BdrvTrackedRequestType type; 74 75 bool serialising; 76 int64_t overlap_offset; 77 unsigned int overlap_bytes; 78 79 QLIST_ENTRY(BdrvTrackedRequest) list; 80 Coroutine *co; /* owner, used for deadlock detection */ 81 CoQueue wait_queue; /* coroutines blocked on this request */ 82 83 struct BdrvTrackedRequest *waiting_for; 84 } BdrvTrackedRequest; 85 86 struct BlockDriver { 87 const char *format_name; 88 int instance_size; 89 90 /* set to true if the BlockDriver is a block filter. Block filters pass 91 * certain callbacks that refer to data (see block.c) to their bs->file if 92 * the driver doesn't implement them. Drivers that do not wish to forward 93 * must implement them and return -ENOTSUP. 94 */ 95 bool is_filter; 96 /* for snapshots block filter like Quorum can implement the 97 * following recursive callback. 98 * It's purpose is to recurse on the filter children while calling 99 * bdrv_recurse_is_first_non_filter on them. 100 * For a sample implementation look in the future Quorum block filter. 101 */ 102 bool (*bdrv_recurse_is_first_non_filter)(BlockDriverState *bs, 103 BlockDriverState *candidate); 104 105 int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename); 106 int (*bdrv_probe_device)(const char *filename); 107 108 /* Any driver implementing this callback is expected to be able to handle 109 * NULL file names in its .bdrv_open() implementation */ 110 void (*bdrv_parse_filename)(const char *filename, QDict *options, Error **errp); 111 /* Drivers not implementing bdrv_parse_filename nor bdrv_open should have 112 * this field set to true, except ones that are defined only by their 113 * child's bs. 114 * An example of the last type will be the quorum block driver. 115 */ 116 bool bdrv_needs_filename; 117 118 /* Set if a driver can support backing files */ 119 bool supports_backing; 120 121 /* For handling image reopen for split or non-split files */ 122 int (*bdrv_reopen_prepare)(BDRVReopenState *reopen_state, 123 BlockReopenQueue *queue, Error **errp); 124 void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state); 125 void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state); 126 void (*bdrv_join_options)(QDict *options, QDict *old_options); 127 128 int (*bdrv_open)(BlockDriverState *bs, QDict *options, int flags, 129 Error **errp); 130 int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags, 131 Error **errp); 132 void (*bdrv_close)(BlockDriverState *bs); 133 int (*bdrv_create)(const char *filename, QemuOpts *opts, Error **errp); 134 int (*bdrv_make_empty)(BlockDriverState *bs); 135 136 void (*bdrv_refresh_filename)(BlockDriverState *bs, QDict *options); 137 138 /* aio */ 139 BlockAIOCB *(*bdrv_aio_readv)(BlockDriverState *bs, 140 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 141 BlockCompletionFunc *cb, void *opaque); 142 BlockAIOCB *(*bdrv_aio_writev)(BlockDriverState *bs, 143 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 144 BlockCompletionFunc *cb, void *opaque); 145 BlockAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs, 146 BlockCompletionFunc *cb, void *opaque); 147 BlockAIOCB *(*bdrv_aio_pdiscard)(BlockDriverState *bs, 148 int64_t offset, int bytes, 149 BlockCompletionFunc *cb, void *opaque); 150 151 int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs, 152 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); 153 154 /** 155 * @offset: position in bytes to read at 156 * @bytes: number of bytes to read 157 * @qiov: the buffers to fill with read data 158 * @flags: currently unused, always 0 159 * 160 * @offset and @bytes will be a multiple of 'request_alignment', 161 * but the length of individual @qiov elements does not have to 162 * be a multiple. 163 * 164 * @bytes will always equal the total size of @qiov, and will be 165 * no larger than 'max_transfer'. 166 * 167 * The buffer in @qiov may point directly to guest memory. 168 */ 169 int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs, 170 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags); 171 int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs, 172 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); 173 int coroutine_fn (*bdrv_co_writev_flags)(BlockDriverState *bs, 174 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int flags); 175 /** 176 * @offset: position in bytes to write at 177 * @bytes: number of bytes to write 178 * @qiov: the buffers containing data to write 179 * @flags: zero or more bits allowed by 'supported_write_flags' 180 * 181 * @offset and @bytes will be a multiple of 'request_alignment', 182 * but the length of individual @qiov elements does not have to 183 * be a multiple. 184 * 185 * @bytes will always equal the total size of @qiov, and will be 186 * no larger than 'max_transfer'. 187 * 188 * The buffer in @qiov may point directly to guest memory. 189 */ 190 int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs, 191 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags); 192 193 /* 194 * Efficiently zero a region of the disk image. Typically an image format 195 * would use a compact metadata representation to implement this. This 196 * function pointer may be NULL or return -ENOSUP and .bdrv_co_writev() 197 * will be called instead. 198 */ 199 int coroutine_fn (*bdrv_co_pwrite_zeroes)(BlockDriverState *bs, 200 int64_t offset, int bytes, BdrvRequestFlags flags); 201 int coroutine_fn (*bdrv_co_pdiscard)(BlockDriverState *bs, 202 int64_t offset, int bytes); 203 204 /* 205 * Building block for bdrv_block_status[_above]. The driver should 206 * answer only according to the current layer, and should not 207 * set BDRV_BLOCK_ALLOCATED, but may set BDRV_BLOCK_RAW. See block.h 208 * for the meaning of _DATA, _ZERO, and _OFFSET_VALID. 209 */ 210 int64_t coroutine_fn (*bdrv_co_get_block_status)(BlockDriverState *bs, 211 int64_t sector_num, int nb_sectors, int *pnum, 212 BlockDriverState **file); 213 214 /* 215 * Invalidate any cached meta-data. 216 */ 217 void (*bdrv_invalidate_cache)(BlockDriverState *bs, Error **errp); 218 int (*bdrv_inactivate)(BlockDriverState *bs); 219 220 /* 221 * Flushes all data for all layers by calling bdrv_co_flush for underlying 222 * layers, if needed. This function is needed for deterministic 223 * synchronization of the flush finishing callback. 224 */ 225 int coroutine_fn (*bdrv_co_flush)(BlockDriverState *bs); 226 227 /* 228 * Flushes all data that was already written to the OS all the way down to 229 * the disk (for example file-posix.c calls fsync()). 230 */ 231 int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs); 232 233 /* 234 * Flushes all internal caches to the OS. The data may still sit in a 235 * writeback cache of the host OS, but it will survive a crash of the qemu 236 * process. 237 */ 238 int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs); 239 240 const char *protocol_name; 241 int (*bdrv_truncate)(BlockDriverState *bs, int64_t offset, 242 PreallocMode prealloc, Error **errp); 243 244 int64_t (*bdrv_getlength)(BlockDriverState *bs); 245 bool has_variable_length; 246 int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs); 247 BlockMeasureInfo *(*bdrv_measure)(QemuOpts *opts, BlockDriverState *in_bs, 248 Error **errp); 249 250 int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs, 251 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov); 252 253 int (*bdrv_snapshot_create)(BlockDriverState *bs, 254 QEMUSnapshotInfo *sn_info); 255 int (*bdrv_snapshot_goto)(BlockDriverState *bs, 256 const char *snapshot_id); 257 int (*bdrv_snapshot_delete)(BlockDriverState *bs, 258 const char *snapshot_id, 259 const char *name, 260 Error **errp); 261 int (*bdrv_snapshot_list)(BlockDriverState *bs, 262 QEMUSnapshotInfo **psn_info); 263 int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs, 264 const char *snapshot_id, 265 const char *name, 266 Error **errp); 267 int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi); 268 ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs); 269 270 int coroutine_fn (*bdrv_save_vmstate)(BlockDriverState *bs, 271 QEMUIOVector *qiov, 272 int64_t pos); 273 int coroutine_fn (*bdrv_load_vmstate)(BlockDriverState *bs, 274 QEMUIOVector *qiov, 275 int64_t pos); 276 277 int (*bdrv_change_backing_file)(BlockDriverState *bs, 278 const char *backing_file, const char *backing_fmt); 279 280 /* removable device specific */ 281 bool (*bdrv_is_inserted)(BlockDriverState *bs); 282 void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag); 283 void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked); 284 285 /* to control generic scsi devices */ 286 BlockAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs, 287 unsigned long int req, void *buf, 288 BlockCompletionFunc *cb, void *opaque); 289 int coroutine_fn (*bdrv_co_ioctl)(BlockDriverState *bs, 290 unsigned long int req, void *buf); 291 292 /* List of options for creating images, terminated by name == NULL */ 293 QemuOptsList *create_opts; 294 295 /* 296 * Returns 0 for completed check, -errno for internal errors. 297 * The check results are stored in result. 298 */ 299 int (*bdrv_check)(BlockDriverState *bs, BdrvCheckResult *result, 300 BdrvCheckMode fix); 301 302 int (*bdrv_amend_options)(BlockDriverState *bs, QemuOpts *opts, 303 BlockDriverAmendStatusCB *status_cb, 304 void *cb_opaque); 305 306 void (*bdrv_debug_event)(BlockDriverState *bs, BlkdebugEvent event); 307 308 /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */ 309 int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event, 310 const char *tag); 311 int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs, 312 const char *tag); 313 int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag); 314 bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag); 315 316 void (*bdrv_refresh_limits)(BlockDriverState *bs, Error **errp); 317 318 /* 319 * Returns 1 if newly created images are guaranteed to contain only 320 * zeros, 0 otherwise. 321 */ 322 int (*bdrv_has_zero_init)(BlockDriverState *bs); 323 324 /* Remove fd handlers, timers, and other event loop callbacks so the event 325 * loop is no longer in use. Called with no in-flight requests and in 326 * depth-first traversal order with parents before child nodes. 327 */ 328 void (*bdrv_detach_aio_context)(BlockDriverState *bs); 329 330 /* Add fd handlers, timers, and other event loop callbacks so I/O requests 331 * can be processed again. Called with no in-flight requests and in 332 * depth-first traversal order with child nodes before parent nodes. 333 */ 334 void (*bdrv_attach_aio_context)(BlockDriverState *bs, 335 AioContext *new_context); 336 337 /* io queue for linux-aio */ 338 void (*bdrv_io_plug)(BlockDriverState *bs); 339 void (*bdrv_io_unplug)(BlockDriverState *bs); 340 341 /** 342 * Try to get @bs's logical and physical block size. 343 * On success, store them in @bsz and return zero. 344 * On failure, return negative errno. 345 */ 346 int (*bdrv_probe_blocksizes)(BlockDriverState *bs, BlockSizes *bsz); 347 /** 348 * Try to get @bs's geometry (cyls, heads, sectors) 349 * On success, store them in @geo and return 0. 350 * On failure return -errno. 351 * Only drivers that want to override guest geometry implement this 352 * callback; see hd_geometry_guess(). 353 */ 354 int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo); 355 356 /** 357 * Drain and stop any internal sources of requests in the driver, and 358 * remain so until next I/O callback (e.g. bdrv_co_writev) is called. 359 */ 360 void coroutine_fn (*bdrv_co_drain)(BlockDriverState *bs); 361 362 void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child, 363 Error **errp); 364 void (*bdrv_del_child)(BlockDriverState *parent, BdrvChild *child, 365 Error **errp); 366 367 /** 368 * Informs the block driver that a permission change is intended. The 369 * driver checks whether the change is permissible and may take other 370 * preparations for the change (e.g. get file system locks). This operation 371 * is always followed either by a call to either .bdrv_set_perm or 372 * .bdrv_abort_perm_update. 373 * 374 * Checks whether the requested set of cumulative permissions in @perm 375 * can be granted for accessing @bs and whether no other users are using 376 * permissions other than those given in @shared (both arguments take 377 * BLK_PERM_* bitmasks). 378 * 379 * If both conditions are met, 0 is returned. Otherwise, -errno is returned 380 * and errp is set to an error describing the conflict. 381 */ 382 int (*bdrv_check_perm)(BlockDriverState *bs, uint64_t perm, 383 uint64_t shared, Error **errp); 384 385 /** 386 * Called to inform the driver that the set of cumulative set of used 387 * permissions for @bs has changed to @perm, and the set of sharable 388 * permission to @shared. The driver can use this to propagate changes to 389 * its children (i.e. request permissions only if a parent actually needs 390 * them). 391 * 392 * This function is only invoked after bdrv_check_perm(), so block drivers 393 * may rely on preparations made in their .bdrv_check_perm implementation. 394 */ 395 void (*bdrv_set_perm)(BlockDriverState *bs, uint64_t perm, uint64_t shared); 396 397 /* 398 * Called to inform the driver that after a previous bdrv_check_perm() 399 * call, the permission update is not performed and any preparations made 400 * for it (e.g. taken file locks) need to be undone. 401 * 402 * This function can be called even for nodes that never saw a 403 * bdrv_check_perm() call. It is a no-op then. 404 */ 405 void (*bdrv_abort_perm_update)(BlockDriverState *bs); 406 407 /** 408 * Returns in @nperm and @nshared the permissions that the driver for @bs 409 * needs on its child @c, based on the cumulative permissions requested by 410 * the parents in @parent_perm and @parent_shared. 411 * 412 * If @c is NULL, return the permissions for attaching a new child for the 413 * given @role. 414 */ 415 void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c, 416 const BdrvChildRole *role, 417 uint64_t parent_perm, uint64_t parent_shared, 418 uint64_t *nperm, uint64_t *nshared); 419 420 /** 421 * Bitmaps should be marked as 'IN_USE' in the image on reopening image 422 * as rw. This handler should realize it. It also should unset readonly 423 * field of BlockDirtyBitmap's in case of success. 424 */ 425 int (*bdrv_reopen_bitmaps_rw)(BlockDriverState *bs, Error **errp); 426 bool (*bdrv_can_store_new_dirty_bitmap)(BlockDriverState *bs, 427 const char *name, 428 uint32_t granularity, 429 Error **errp); 430 void (*bdrv_remove_persistent_dirty_bitmap)(BlockDriverState *bs, 431 const char *name, 432 Error **errp); 433 434 QLIST_ENTRY(BlockDriver) list; 435 }; 436 437 typedef struct BlockLimits { 438 /* Alignment requirement, in bytes, for offset/length of I/O 439 * requests. Must be a power of 2 less than INT_MAX; defaults to 440 * 1 for drivers with modern byte interfaces, and to 512 441 * otherwise. */ 442 uint32_t request_alignment; 443 444 /* Maximum number of bytes that can be discarded at once (since it 445 * is signed, it must be < 2G, if set). Must be multiple of 446 * pdiscard_alignment, but need not be power of 2. May be 0 if no 447 * inherent 32-bit limit */ 448 int32_t max_pdiscard; 449 450 /* Optimal alignment for discard requests in bytes. A power of 2 451 * is best but not mandatory. Must be a multiple of 452 * bl.request_alignment, and must be less than max_pdiscard if 453 * that is set. May be 0 if bl.request_alignment is good enough */ 454 uint32_t pdiscard_alignment; 455 456 /* Maximum number of bytes that can zeroized at once (since it is 457 * signed, it must be < 2G, if set). Must be multiple of 458 * pwrite_zeroes_alignment. May be 0 if no inherent 32-bit limit */ 459 int32_t max_pwrite_zeroes; 460 461 /* Optimal alignment for write zeroes requests in bytes. A power 462 * of 2 is best but not mandatory. Must be a multiple of 463 * bl.request_alignment, and must be less than max_pwrite_zeroes 464 * if that is set. May be 0 if bl.request_alignment is good 465 * enough */ 466 uint32_t pwrite_zeroes_alignment; 467 468 /* Optimal transfer length in bytes. A power of 2 is best but not 469 * mandatory. Must be a multiple of bl.request_alignment, or 0 if 470 * no preferred size */ 471 uint32_t opt_transfer; 472 473 /* Maximal transfer length in bytes. Need not be power of 2, but 474 * must be multiple of opt_transfer and bl.request_alignment, or 0 475 * for no 32-bit limit. For now, anything larger than INT_MAX is 476 * clamped down. */ 477 uint32_t max_transfer; 478 479 /* memory alignment, in bytes so that no bounce buffer is needed */ 480 size_t min_mem_alignment; 481 482 /* memory alignment, in bytes, for bounce buffer */ 483 size_t opt_mem_alignment; 484 485 /* maximum number of iovec elements */ 486 int max_iov; 487 } BlockLimits; 488 489 typedef struct BdrvOpBlocker BdrvOpBlocker; 490 491 typedef struct BdrvAioNotifier { 492 void (*attached_aio_context)(AioContext *new_context, void *opaque); 493 void (*detach_aio_context)(void *opaque); 494 495 void *opaque; 496 bool deleted; 497 498 QLIST_ENTRY(BdrvAioNotifier) list; 499 } BdrvAioNotifier; 500 501 struct BdrvChildRole { 502 /* If true, bdrv_replace_node() doesn't change the node this BdrvChild 503 * points to. */ 504 bool stay_at_node; 505 506 void (*inherit_options)(int *child_flags, QDict *child_options, 507 int parent_flags, QDict *parent_options); 508 509 void (*change_media)(BdrvChild *child, bool load); 510 void (*resize)(BdrvChild *child); 511 512 /* Returns a name that is supposedly more useful for human users than the 513 * node name for identifying the node in question (in particular, a BB 514 * name), or NULL if the parent can't provide a better name. */ 515 const char *(*get_name)(BdrvChild *child); 516 517 /* Returns a malloced string that describes the parent of the child for a 518 * human reader. This could be a node-name, BlockBackend name, qdev ID or 519 * QOM path of the device owning the BlockBackend, job type and ID etc. The 520 * caller is responsible for freeing the memory. */ 521 char *(*get_parent_desc)(BdrvChild *child); 522 523 /* 524 * If this pair of functions is implemented, the parent doesn't issue new 525 * requests after returning from .drained_begin() until .drained_end() is 526 * called. 527 * 528 * Note that this can be nested. If drained_begin() was called twice, new 529 * I/O is allowed only after drained_end() was called twice, too. 530 */ 531 void (*drained_begin)(BdrvChild *child); 532 void (*drained_end)(BdrvChild *child); 533 534 /* Notifies the parent that the child has been activated/inactivated (e.g. 535 * when migration is completing) and it can start/stop requesting 536 * permissions and doing I/O on it. */ 537 void (*activate)(BdrvChild *child, Error **errp); 538 int (*inactivate)(BdrvChild *child); 539 540 void (*attach)(BdrvChild *child); 541 void (*detach)(BdrvChild *child); 542 }; 543 544 extern const BdrvChildRole child_file; 545 extern const BdrvChildRole child_format; 546 extern const BdrvChildRole child_backing; 547 548 struct BdrvChild { 549 BlockDriverState *bs; 550 char *name; 551 const BdrvChildRole *role; 552 void *opaque; 553 554 /** 555 * Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask) 556 */ 557 uint64_t perm; 558 559 /** 560 * Permissions that can still be granted to other users of @bs while this 561 * BdrvChild is still attached to it. (BLK_PERM_* bitmask) 562 */ 563 uint64_t shared_perm; 564 565 QLIST_ENTRY(BdrvChild) next; 566 QLIST_ENTRY(BdrvChild) next_parent; 567 }; 568 569 /* 570 * Note: the function bdrv_append() copies and swaps contents of 571 * BlockDriverStates, so if you add new fields to this struct, please 572 * inspect bdrv_append() to determine if the new fields need to be 573 * copied as well. 574 */ 575 struct BlockDriverState { 576 /* Protected by big QEMU lock or read-only after opening. No special 577 * locking needed during I/O... 578 */ 579 int open_flags; /* flags used to open the file, re-used for re-open */ 580 bool read_only; /* if true, the media is read only */ 581 bool encrypted; /* if true, the media is encrypted */ 582 bool sg; /* if true, the device is a /dev/sg* */ 583 bool probed; /* if true, format was probed rather than specified */ 584 bool force_share; /* if true, always allow all shared permissions */ 585 bool implicit; /* if true, this filter node was automatically inserted */ 586 587 BlockDriver *drv; /* NULL means no media */ 588 void *opaque; 589 590 AioContext *aio_context; /* event loop used for fd handlers, timers, etc */ 591 /* long-running tasks intended to always use the same AioContext as this 592 * BDS may register themselves in this list to be notified of changes 593 * regarding this BDS's context */ 594 QLIST_HEAD(, BdrvAioNotifier) aio_notifiers; 595 bool walking_aio_notifiers; /* to make removal during iteration safe */ 596 597 char filename[PATH_MAX]; 598 char backing_file[PATH_MAX]; /* if non zero, the image is a diff of 599 this file image */ 600 char backing_format[16]; /* if non-zero and backing_file exists */ 601 602 QDict *full_open_options; 603 char exact_filename[PATH_MAX]; 604 605 BdrvChild *backing; 606 BdrvChild *file; 607 608 /* I/O Limits */ 609 BlockLimits bl; 610 611 /* Flags honored during pwrite (so far: BDRV_REQ_FUA) */ 612 unsigned int supported_write_flags; 613 /* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA, 614 * BDRV_REQ_MAY_UNMAP) */ 615 unsigned int supported_zero_flags; 616 617 /* the following member gives a name to every node on the bs graph. */ 618 char node_name[32]; 619 /* element of the list of named nodes building the graph */ 620 QTAILQ_ENTRY(BlockDriverState) node_list; 621 /* element of the list of all BlockDriverStates (all_bdrv_states) */ 622 QTAILQ_ENTRY(BlockDriverState) bs_list; 623 /* element of the list of monitor-owned BDS */ 624 QTAILQ_ENTRY(BlockDriverState) monitor_list; 625 int refcnt; 626 627 /* operation blockers */ 628 QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; 629 630 /* long-running background operation */ 631 BlockJob *job; 632 633 /* The node that this node inherited default options from (and a reopen on 634 * which can affect this node by changing these defaults). This is always a 635 * parent node of this node. */ 636 BlockDriverState *inherits_from; 637 QLIST_HEAD(, BdrvChild) children; 638 QLIST_HEAD(, BdrvChild) parents; 639 640 QDict *options; 641 QDict *explicit_options; 642 BlockdevDetectZeroesOptions detect_zeroes; 643 644 /* The error object in use for blocking operations on backing_hd */ 645 Error *backing_blocker; 646 647 /* Protected by AioContext lock */ 648 649 /* If we are reading a disk image, give its size in sectors. 650 * Generally read-only; it is written to by load_snapshot and 651 * save_snaphost, but the block layer is quiescent during those. 652 */ 653 int64_t total_sectors; 654 655 /* Callback before write request is processed */ 656 NotifierWithReturnList before_write_notifiers; 657 658 /* threshold limit for writes, in bytes. "High water mark". */ 659 uint64_t write_threshold_offset; 660 NotifierWithReturn write_threshold_notifier; 661 662 /* Writing to the list requires the BQL _and_ the dirty_bitmap_mutex. 663 * Reading from the list can be done with either the BQL or the 664 * dirty_bitmap_mutex. Modifying a bitmap only requires 665 * dirty_bitmap_mutex. */ 666 QemuMutex dirty_bitmap_mutex; 667 QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps; 668 669 /* Offset after the highest byte written to */ 670 Stat64 wr_highest_offset; 671 672 /* If true, copy read backing sectors into image. Can be >1 if more 673 * than one client has requested copy-on-read. Accessed with atomic 674 * ops. 675 */ 676 int copy_on_read; 677 678 /* number of in-flight requests; overall and serialising. 679 * Accessed with atomic ops. 680 */ 681 unsigned int in_flight; 682 unsigned int serialising_in_flight; 683 684 /* Internal to BDRV_POLL_WHILE and bdrv_wakeup. Accessed with atomic 685 * ops. 686 */ 687 bool wakeup; 688 689 /* counter for nested bdrv_io_plug. 690 * Accessed with atomic ops. 691 */ 692 unsigned io_plugged; 693 694 /* do we need to tell the quest if we have a volatile write cache? */ 695 int enable_write_cache; 696 697 /* Accessed with atomic ops. */ 698 int quiesce_counter; 699 unsigned int write_gen; /* Current data generation */ 700 701 /* Protected by reqs_lock. */ 702 CoMutex reqs_lock; 703 QLIST_HEAD(, BdrvTrackedRequest) tracked_requests; 704 CoQueue flush_queue; /* Serializing flush queue */ 705 bool active_flush_req; /* Flush request in flight? */ 706 707 /* Only read/written by whoever has set active_flush_req to true. */ 708 unsigned int flushed_gen; /* Flushed write generation */ 709 }; 710 711 struct BlockBackendRootState { 712 int open_flags; 713 bool read_only; 714 BlockdevDetectZeroesOptions detect_zeroes; 715 }; 716 717 typedef enum BlockMirrorBackingMode { 718 /* Reuse the existing backing chain from the source for the target. 719 * - sync=full: Set backing BDS to NULL. 720 * - sync=top: Use source's backing BDS. 721 * - sync=none: Use source as the backing BDS. */ 722 MIRROR_SOURCE_BACKING_CHAIN, 723 724 /* Open the target's backing chain completely anew */ 725 MIRROR_OPEN_BACKING_CHAIN, 726 727 /* Do not change the target's backing BDS after job completion */ 728 MIRROR_LEAVE_BACKING_CHAIN, 729 } BlockMirrorBackingMode; 730 731 static inline BlockDriverState *backing_bs(BlockDriverState *bs) 732 { 733 return bs->backing ? bs->backing->bs : NULL; 734 } 735 736 737 /* Essential block drivers which must always be statically linked into qemu, and 738 * which therefore can be accessed without using bdrv_find_format() */ 739 extern BlockDriver bdrv_file; 740 extern BlockDriver bdrv_raw; 741 extern BlockDriver bdrv_qcow2; 742 743 int coroutine_fn bdrv_co_preadv(BdrvChild *child, 744 int64_t offset, unsigned int bytes, QEMUIOVector *qiov, 745 BdrvRequestFlags flags); 746 int coroutine_fn bdrv_co_pwritev(BdrvChild *child, 747 int64_t offset, unsigned int bytes, QEMUIOVector *qiov, 748 BdrvRequestFlags flags); 749 750 int get_tmp_filename(char *filename, int size); 751 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size, 752 const char *filename); 753 754 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, 755 QDict *options); 756 757 758 /** 759 * bdrv_add_before_write_notifier: 760 * 761 * Register a callback that is invoked before write requests are processed but 762 * after any throttling or waiting for overlapping requests. 763 */ 764 void bdrv_add_before_write_notifier(BlockDriverState *bs, 765 NotifierWithReturn *notifier); 766 767 /** 768 * bdrv_detach_aio_context: 769 * 770 * May be called from .bdrv_detach_aio_context() to detach children from the 771 * current #AioContext. This is only needed by block drivers that manage their 772 * own children. Both ->file and ->backing are automatically handled and 773 * block drivers should not call this function on them explicitly. 774 */ 775 void bdrv_detach_aio_context(BlockDriverState *bs); 776 777 /** 778 * bdrv_attach_aio_context: 779 * 780 * May be called from .bdrv_attach_aio_context() to attach children to the new 781 * #AioContext. This is only needed by block drivers that manage their own 782 * children. Both ->file and ->backing are automatically handled and block 783 * drivers should not call this function on them explicitly. 784 */ 785 void bdrv_attach_aio_context(BlockDriverState *bs, 786 AioContext *new_context); 787 788 /** 789 * bdrv_add_aio_context_notifier: 790 * 791 * If a long-running job intends to be always run in the same AioContext as a 792 * certain BDS, it may use this function to be notified of changes regarding the 793 * association of the BDS to an AioContext. 794 * 795 * attached_aio_context() is called after the target BDS has been attached to a 796 * new AioContext; detach_aio_context() is called before the target BDS is being 797 * detached from its old AioContext. 798 */ 799 void bdrv_add_aio_context_notifier(BlockDriverState *bs, 800 void (*attached_aio_context)(AioContext *new_context, void *opaque), 801 void (*detach_aio_context)(void *opaque), void *opaque); 802 803 /** 804 * bdrv_remove_aio_context_notifier: 805 * 806 * Unsubscribe of change notifications regarding the BDS's AioContext. The 807 * parameters given here have to be the same as those given to 808 * bdrv_add_aio_context_notifier(). 809 */ 810 void bdrv_remove_aio_context_notifier(BlockDriverState *bs, 811 void (*aio_context_attached)(AioContext *, 812 void *), 813 void (*aio_context_detached)(void *), 814 void *opaque); 815 816 /** 817 * bdrv_wakeup: 818 * @bs: The BlockDriverState for which an I/O operation has been completed. 819 * 820 * Wake up the main thread if it is waiting on BDRV_POLL_WHILE. During 821 * synchronous I/O on a BlockDriverState that is attached to another 822 * I/O thread, the main thread lets the I/O thread's event loop run, 823 * waiting for the I/O operation to complete. A bdrv_wakeup will wake 824 * up the main thread if necessary. 825 * 826 * Manual calls to bdrv_wakeup are rarely necessary, because 827 * bdrv_dec_in_flight already calls it. 828 */ 829 void bdrv_wakeup(BlockDriverState *bs); 830 831 #ifdef _WIN32 832 int is_windows_drive(const char *filename); 833 #endif 834 835 /** 836 * stream_start: 837 * @job_id: The id of the newly-created job, or %NULL to use the 838 * device name of @bs. 839 * @bs: Block device to operate on. 840 * @base: Block device that will become the new base, or %NULL to 841 * flatten the whole backing file chain onto @bs. 842 * @backing_file_str: The file name that will be written to @bs as the 843 * the new backing file if the job completes. Ignored if @base is %NULL. 844 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 845 * @on_error: The action to take upon error. 846 * @errp: Error object. 847 * 848 * Start a streaming operation on @bs. Clusters that are unallocated 849 * in @bs, but allocated in any image between @base and @bs (both 850 * exclusive) will be written to @bs. At the end of a successful 851 * streaming job, the backing file of @bs will be changed to 852 * @backing_file_str in the written image and to @base in the live 853 * BlockDriverState. 854 */ 855 void stream_start(const char *job_id, BlockDriverState *bs, 856 BlockDriverState *base, const char *backing_file_str, 857 int64_t speed, BlockdevOnError on_error, Error **errp); 858 859 /** 860 * commit_start: 861 * @job_id: The id of the newly-created job, or %NULL to use the 862 * device name of @bs. 863 * @bs: Active block device. 864 * @top: Top block device to be committed. 865 * @base: Block device that will be written into, and become the new top. 866 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 867 * @on_error: The action to take upon error. 868 * @backing_file_str: String to use as the backing file in @top's overlay 869 * @filter_node_name: The node name that should be assigned to the filter 870 * driver that the commit job inserts into the graph above @top. NULL means 871 * that a node name should be autogenerated. 872 * @errp: Error object. 873 * 874 */ 875 void commit_start(const char *job_id, BlockDriverState *bs, 876 BlockDriverState *base, BlockDriverState *top, int64_t speed, 877 BlockdevOnError on_error, const char *backing_file_str, 878 const char *filter_node_name, Error **errp); 879 /** 880 * commit_active_start: 881 * @job_id: The id of the newly-created job, or %NULL to use the 882 * device name of @bs. 883 * @bs: Active block device to be committed. 884 * @base: Block device that will be written into, and become the new top. 885 * @creation_flags: Flags that control the behavior of the Job lifetime. 886 * See @BlockJobCreateFlags 887 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 888 * @on_error: The action to take upon error. 889 * @filter_node_name: The node name that should be assigned to the filter 890 * driver that the commit job inserts into the graph above @bs. NULL means that 891 * a node name should be autogenerated. 892 * @cb: Completion function for the job. 893 * @opaque: Opaque pointer value passed to @cb. 894 * @auto_complete: Auto complete the job. 895 * @errp: Error object. 896 * 897 */ 898 void commit_active_start(const char *job_id, BlockDriverState *bs, 899 BlockDriverState *base, int creation_flags, 900 int64_t speed, BlockdevOnError on_error, 901 const char *filter_node_name, 902 BlockCompletionFunc *cb, void *opaque, 903 bool auto_complete, Error **errp); 904 /* 905 * mirror_start: 906 * @job_id: The id of the newly-created job, or %NULL to use the 907 * device name of @bs. 908 * @bs: Block device to operate on. 909 * @target: Block device to write to. 910 * @replaces: Block graph node name to replace once the mirror is done. Can 911 * only be used when full mirroring is selected. 912 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 913 * @granularity: The chosen granularity for the dirty bitmap. 914 * @buf_size: The amount of data that can be in flight at one time. 915 * @mode: Whether to collapse all images in the chain to the target. 916 * @backing_mode: How to establish the target's backing chain after completion. 917 * @on_source_error: The action to take upon error reading from the source. 918 * @on_target_error: The action to take upon error writing to the target. 919 * @unmap: Whether to unmap target where source sectors only contain zeroes. 920 * @filter_node_name: The node name that should be assigned to the filter 921 * driver that the mirror job inserts into the graph above @bs. NULL means that 922 * a node name should be autogenerated. 923 * @errp: Error object. 924 * 925 * Start a mirroring operation on @bs. Clusters that are allocated 926 * in @bs will be written to @target until the job is cancelled or 927 * manually completed. At the end of a successful mirroring job, 928 * @bs will be switched to read from @target. 929 */ 930 void mirror_start(const char *job_id, BlockDriverState *bs, 931 BlockDriverState *target, const char *replaces, 932 int64_t speed, uint32_t granularity, int64_t buf_size, 933 MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, 934 BlockdevOnError on_source_error, 935 BlockdevOnError on_target_error, 936 bool unmap, const char *filter_node_name, Error **errp); 937 938 /* 939 * backup_job_create: 940 * @job_id: The id of the newly-created job, or %NULL to use the 941 * device name of @bs. 942 * @bs: Block device to operate on. 943 * @target: Block device to write to. 944 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 945 * @sync_mode: What parts of the disk image should be copied to the destination. 946 * @sync_bitmap: The dirty bitmap if sync_mode is MIRROR_SYNC_MODE_INCREMENTAL. 947 * @on_source_error: The action to take upon error reading from the source. 948 * @on_target_error: The action to take upon error writing to the target. 949 * @creation_flags: Flags that control the behavior of the Job lifetime. 950 * See @BlockJobCreateFlags 951 * @cb: Completion function for the job. 952 * @opaque: Opaque pointer value passed to @cb. 953 * @txn: Transaction that this job is part of (may be NULL). 954 * 955 * Create a backup operation on @bs. Clusters in @bs are written to @target 956 * until the job is cancelled or manually completed. 957 */ 958 BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, 959 BlockDriverState *target, int64_t speed, 960 MirrorSyncMode sync_mode, 961 BdrvDirtyBitmap *sync_bitmap, 962 bool compress, 963 BlockdevOnError on_source_error, 964 BlockdevOnError on_target_error, 965 int creation_flags, 966 BlockCompletionFunc *cb, void *opaque, 967 BlockJobTxn *txn, Error **errp); 968 969 void hmp_drive_add_node(Monitor *mon, const char *optstr); 970 971 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, 972 const char *child_name, 973 const BdrvChildRole *child_role, 974 uint64_t perm, uint64_t shared_perm, 975 void *opaque, Error **errp); 976 void bdrv_root_unref_child(BdrvChild *child); 977 978 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, 979 Error **errp); 980 981 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by 982 * block filters: Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED and RESIZE to 983 * all children */ 984 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c, 985 const BdrvChildRole *role, 986 uint64_t perm, uint64_t shared, 987 uint64_t *nperm, uint64_t *nshared); 988 989 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by 990 * (non-raw) image formats: Like above for bs->backing, but for bs->file it 991 * requires WRITE | RESIZE for read-write images, always requires 992 * CONSISTENT_READ and doesn't share WRITE. */ 993 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c, 994 const BdrvChildRole *role, 995 uint64_t perm, uint64_t shared, 996 uint64_t *nperm, uint64_t *nshared); 997 998 /* 999 * Default implementation for drivers to pass bdrv_co_get_block_status() to 1000 * their file. 1001 */ 1002 int64_t coroutine_fn bdrv_co_get_block_status_from_file(BlockDriverState *bs, 1003 int64_t sector_num, 1004 int nb_sectors, 1005 int *pnum, 1006 BlockDriverState **file); 1007 /* 1008 * Default implementation for drivers to pass bdrv_co_get_block_status() to 1009 * their backing file. 1010 */ 1011 int64_t coroutine_fn bdrv_co_get_block_status_from_backing(BlockDriverState *bs, 1012 int64_t sector_num, 1013 int nb_sectors, 1014 int *pnum, 1015 BlockDriverState **file); 1016 const char *bdrv_get_parent_name(const BlockDriverState *bs); 1017 void blk_dev_change_media_cb(BlockBackend *blk, bool load, Error **errp); 1018 bool blk_dev_has_removable_media(BlockBackend *blk); 1019 bool blk_dev_has_tray(BlockBackend *blk); 1020 void blk_dev_eject_request(BlockBackend *blk, bool force); 1021 bool blk_dev_is_tray_open(BlockBackend *blk); 1022 bool blk_dev_is_medium_locked(BlockBackend *blk); 1023 1024 void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector, int64_t nr_sect); 1025 bool bdrv_requests_pending(BlockDriverState *bs); 1026 1027 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out); 1028 void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in); 1029 1030 void bdrv_inc_in_flight(BlockDriverState *bs); 1031 void bdrv_dec_in_flight(BlockDriverState *bs); 1032 1033 void blockdev_close_all_bdrv_states(void); 1034 1035 #endif /* BLOCK_INT_H */ 1036