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 * If @reopen_queue is non-NULL, don't return the currently needed 416 * permissions, but those that will be needed after applying the 417 * @reopen_queue. 418 */ 419 void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c, 420 const BdrvChildRole *role, 421 BlockReopenQueue *reopen_queue, 422 uint64_t parent_perm, uint64_t parent_shared, 423 uint64_t *nperm, uint64_t *nshared); 424 425 /** 426 * Bitmaps should be marked as 'IN_USE' in the image on reopening image 427 * as rw. This handler should realize it. It also should unset readonly 428 * field of BlockDirtyBitmap's in case of success. 429 */ 430 int (*bdrv_reopen_bitmaps_rw)(BlockDriverState *bs, Error **errp); 431 bool (*bdrv_can_store_new_dirty_bitmap)(BlockDriverState *bs, 432 const char *name, 433 uint32_t granularity, 434 Error **errp); 435 void (*bdrv_remove_persistent_dirty_bitmap)(BlockDriverState *bs, 436 const char *name, 437 Error **errp); 438 439 QLIST_ENTRY(BlockDriver) list; 440 }; 441 442 typedef struct BlockLimits { 443 /* Alignment requirement, in bytes, for offset/length of I/O 444 * requests. Must be a power of 2 less than INT_MAX; defaults to 445 * 1 for drivers with modern byte interfaces, and to 512 446 * otherwise. */ 447 uint32_t request_alignment; 448 449 /* Maximum number of bytes that can be discarded at once (since it 450 * is signed, it must be < 2G, if set). Must be multiple of 451 * pdiscard_alignment, but need not be power of 2. May be 0 if no 452 * inherent 32-bit limit */ 453 int32_t max_pdiscard; 454 455 /* Optimal alignment for discard requests in bytes. A power of 2 456 * is best but not mandatory. Must be a multiple of 457 * bl.request_alignment, and must be less than max_pdiscard if 458 * that is set. May be 0 if bl.request_alignment is good enough */ 459 uint32_t pdiscard_alignment; 460 461 /* Maximum number of bytes that can zeroized at once (since it is 462 * signed, it must be < 2G, if set). Must be multiple of 463 * pwrite_zeroes_alignment. May be 0 if no inherent 32-bit limit */ 464 int32_t max_pwrite_zeroes; 465 466 /* Optimal alignment for write zeroes requests in bytes. A power 467 * of 2 is best but not mandatory. Must be a multiple of 468 * bl.request_alignment, and must be less than max_pwrite_zeroes 469 * if that is set. May be 0 if bl.request_alignment is good 470 * enough */ 471 uint32_t pwrite_zeroes_alignment; 472 473 /* Optimal transfer length in bytes. A power of 2 is best but not 474 * mandatory. Must be a multiple of bl.request_alignment, or 0 if 475 * no preferred size */ 476 uint32_t opt_transfer; 477 478 /* Maximal transfer length in bytes. Need not be power of 2, but 479 * must be multiple of opt_transfer and bl.request_alignment, or 0 480 * for no 32-bit limit. For now, anything larger than INT_MAX is 481 * clamped down. */ 482 uint32_t max_transfer; 483 484 /* memory alignment, in bytes so that no bounce buffer is needed */ 485 size_t min_mem_alignment; 486 487 /* memory alignment, in bytes, for bounce buffer */ 488 size_t opt_mem_alignment; 489 490 /* maximum number of iovec elements */ 491 int max_iov; 492 } BlockLimits; 493 494 typedef struct BdrvOpBlocker BdrvOpBlocker; 495 496 typedef struct BdrvAioNotifier { 497 void (*attached_aio_context)(AioContext *new_context, void *opaque); 498 void (*detach_aio_context)(void *opaque); 499 500 void *opaque; 501 bool deleted; 502 503 QLIST_ENTRY(BdrvAioNotifier) list; 504 } BdrvAioNotifier; 505 506 struct BdrvChildRole { 507 /* If true, bdrv_replace_node() doesn't change the node this BdrvChild 508 * points to. */ 509 bool stay_at_node; 510 511 void (*inherit_options)(int *child_flags, QDict *child_options, 512 int parent_flags, QDict *parent_options); 513 514 void (*change_media)(BdrvChild *child, bool load); 515 void (*resize)(BdrvChild *child); 516 517 /* Returns a name that is supposedly more useful for human users than the 518 * node name for identifying the node in question (in particular, a BB 519 * name), or NULL if the parent can't provide a better name. */ 520 const char *(*get_name)(BdrvChild *child); 521 522 /* Returns a malloced string that describes the parent of the child for a 523 * human reader. This could be a node-name, BlockBackend name, qdev ID or 524 * QOM path of the device owning the BlockBackend, job type and ID etc. The 525 * caller is responsible for freeing the memory. */ 526 char *(*get_parent_desc)(BdrvChild *child); 527 528 /* 529 * If this pair of functions is implemented, the parent doesn't issue new 530 * requests after returning from .drained_begin() until .drained_end() is 531 * called. 532 * 533 * Note that this can be nested. If drained_begin() was called twice, new 534 * I/O is allowed only after drained_end() was called twice, too. 535 */ 536 void (*drained_begin)(BdrvChild *child); 537 void (*drained_end)(BdrvChild *child); 538 539 /* Notifies the parent that the child has been activated/inactivated (e.g. 540 * when migration is completing) and it can start/stop requesting 541 * permissions and doing I/O on it. */ 542 void (*activate)(BdrvChild *child, Error **errp); 543 int (*inactivate)(BdrvChild *child); 544 545 void (*attach)(BdrvChild *child); 546 void (*detach)(BdrvChild *child); 547 548 /* Notifies the parent that the filename of its child has changed (e.g. 549 * because the direct child was removed from the backing chain), so that it 550 * can update its reference. */ 551 int (*update_filename)(BdrvChild *child, BlockDriverState *new_base, 552 const char *filename, Error **errp); 553 }; 554 555 extern const BdrvChildRole child_file; 556 extern const BdrvChildRole child_format; 557 extern const BdrvChildRole child_backing; 558 559 struct BdrvChild { 560 BlockDriverState *bs; 561 char *name; 562 const BdrvChildRole *role; 563 void *opaque; 564 565 /** 566 * Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask) 567 */ 568 uint64_t perm; 569 570 /** 571 * Permissions that can still be granted to other users of @bs while this 572 * BdrvChild is still attached to it. (BLK_PERM_* bitmask) 573 */ 574 uint64_t shared_perm; 575 576 QLIST_ENTRY(BdrvChild) next; 577 QLIST_ENTRY(BdrvChild) next_parent; 578 }; 579 580 /* 581 * Note: the function bdrv_append() copies and swaps contents of 582 * BlockDriverStates, so if you add new fields to this struct, please 583 * inspect bdrv_append() to determine if the new fields need to be 584 * copied as well. 585 */ 586 struct BlockDriverState { 587 /* Protected by big QEMU lock or read-only after opening. No special 588 * locking needed during I/O... 589 */ 590 int open_flags; /* flags used to open the file, re-used for re-open */ 591 bool read_only; /* if true, the media is read only */ 592 bool encrypted; /* if true, the media is encrypted */ 593 bool sg; /* if true, the device is a /dev/sg* */ 594 bool probed; /* if true, format was probed rather than specified */ 595 bool force_share; /* if true, always allow all shared permissions */ 596 bool implicit; /* if true, this filter node was automatically inserted */ 597 598 BlockDriver *drv; /* NULL means no media */ 599 void *opaque; 600 601 AioContext *aio_context; /* event loop used for fd handlers, timers, etc */ 602 /* long-running tasks intended to always use the same AioContext as this 603 * BDS may register themselves in this list to be notified of changes 604 * regarding this BDS's context */ 605 QLIST_HEAD(, BdrvAioNotifier) aio_notifiers; 606 bool walking_aio_notifiers; /* to make removal during iteration safe */ 607 608 char filename[PATH_MAX]; 609 char backing_file[PATH_MAX]; /* if non zero, the image is a diff of 610 this file image */ 611 char backing_format[16]; /* if non-zero and backing_file exists */ 612 613 QDict *full_open_options; 614 char exact_filename[PATH_MAX]; 615 616 BdrvChild *backing; 617 BdrvChild *file; 618 619 /* I/O Limits */ 620 BlockLimits bl; 621 622 /* Flags honored during pwrite (so far: BDRV_REQ_FUA) */ 623 unsigned int supported_write_flags; 624 /* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA, 625 * BDRV_REQ_MAY_UNMAP) */ 626 unsigned int supported_zero_flags; 627 628 /* the following member gives a name to every node on the bs graph. */ 629 char node_name[32]; 630 /* element of the list of named nodes building the graph */ 631 QTAILQ_ENTRY(BlockDriverState) node_list; 632 /* element of the list of all BlockDriverStates (all_bdrv_states) */ 633 QTAILQ_ENTRY(BlockDriverState) bs_list; 634 /* element of the list of monitor-owned BDS */ 635 QTAILQ_ENTRY(BlockDriverState) monitor_list; 636 int refcnt; 637 638 /* operation blockers */ 639 QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; 640 641 /* long-running background operation */ 642 BlockJob *job; 643 644 /* The node that this node inherited default options from (and a reopen on 645 * which can affect this node by changing these defaults). This is always a 646 * parent node of this node. */ 647 BlockDriverState *inherits_from; 648 QLIST_HEAD(, BdrvChild) children; 649 QLIST_HEAD(, BdrvChild) parents; 650 651 QDict *options; 652 QDict *explicit_options; 653 BlockdevDetectZeroesOptions detect_zeroes; 654 655 /* The error object in use for blocking operations on backing_hd */ 656 Error *backing_blocker; 657 658 /* Protected by AioContext lock */ 659 660 /* If we are reading a disk image, give its size in sectors. 661 * Generally read-only; it is written to by load_snapshot and 662 * save_snaphost, but the block layer is quiescent during those. 663 */ 664 int64_t total_sectors; 665 666 /* Callback before write request is processed */ 667 NotifierWithReturnList before_write_notifiers; 668 669 /* threshold limit for writes, in bytes. "High water mark". */ 670 uint64_t write_threshold_offset; 671 NotifierWithReturn write_threshold_notifier; 672 673 /* Writing to the list requires the BQL _and_ the dirty_bitmap_mutex. 674 * Reading from the list can be done with either the BQL or the 675 * dirty_bitmap_mutex. Modifying a bitmap only requires 676 * dirty_bitmap_mutex. */ 677 QemuMutex dirty_bitmap_mutex; 678 QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps; 679 680 /* Offset after the highest byte written to */ 681 Stat64 wr_highest_offset; 682 683 /* If true, copy read backing sectors into image. Can be >1 if more 684 * than one client has requested copy-on-read. Accessed with atomic 685 * ops. 686 */ 687 int copy_on_read; 688 689 /* number of in-flight requests; overall and serialising. 690 * Accessed with atomic ops. 691 */ 692 unsigned int in_flight; 693 unsigned int serialising_in_flight; 694 695 /* Internal to BDRV_POLL_WHILE and bdrv_wakeup. Accessed with atomic 696 * ops. 697 */ 698 bool wakeup; 699 700 /* counter for nested bdrv_io_plug. 701 * Accessed with atomic ops. 702 */ 703 unsigned io_plugged; 704 705 /* do we need to tell the quest if we have a volatile write cache? */ 706 int enable_write_cache; 707 708 /* Accessed with atomic ops. */ 709 int quiesce_counter; 710 unsigned int write_gen; /* Current data generation */ 711 712 /* Protected by reqs_lock. */ 713 CoMutex reqs_lock; 714 QLIST_HEAD(, BdrvTrackedRequest) tracked_requests; 715 CoQueue flush_queue; /* Serializing flush queue */ 716 bool active_flush_req; /* Flush request in flight? */ 717 718 /* Only read/written by whoever has set active_flush_req to true. */ 719 unsigned int flushed_gen; /* Flushed write generation */ 720 }; 721 722 struct BlockBackendRootState { 723 int open_flags; 724 bool read_only; 725 BlockdevDetectZeroesOptions detect_zeroes; 726 }; 727 728 typedef enum BlockMirrorBackingMode { 729 /* Reuse the existing backing chain from the source for the target. 730 * - sync=full: Set backing BDS to NULL. 731 * - sync=top: Use source's backing BDS. 732 * - sync=none: Use source as the backing BDS. */ 733 MIRROR_SOURCE_BACKING_CHAIN, 734 735 /* Open the target's backing chain completely anew */ 736 MIRROR_OPEN_BACKING_CHAIN, 737 738 /* Do not change the target's backing BDS after job completion */ 739 MIRROR_LEAVE_BACKING_CHAIN, 740 } BlockMirrorBackingMode; 741 742 static inline BlockDriverState *backing_bs(BlockDriverState *bs) 743 { 744 return bs->backing ? bs->backing->bs : NULL; 745 } 746 747 748 /* Essential block drivers which must always be statically linked into qemu, and 749 * which therefore can be accessed without using bdrv_find_format() */ 750 extern BlockDriver bdrv_file; 751 extern BlockDriver bdrv_raw; 752 extern BlockDriver bdrv_qcow2; 753 754 int coroutine_fn bdrv_co_preadv(BdrvChild *child, 755 int64_t offset, unsigned int bytes, QEMUIOVector *qiov, 756 BdrvRequestFlags flags); 757 int coroutine_fn bdrv_co_pwritev(BdrvChild *child, 758 int64_t offset, unsigned int bytes, QEMUIOVector *qiov, 759 BdrvRequestFlags flags); 760 761 int get_tmp_filename(char *filename, int size); 762 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size, 763 const char *filename); 764 765 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, 766 QDict *options); 767 768 769 /** 770 * bdrv_add_before_write_notifier: 771 * 772 * Register a callback that is invoked before write requests are processed but 773 * after any throttling or waiting for overlapping requests. 774 */ 775 void bdrv_add_before_write_notifier(BlockDriverState *bs, 776 NotifierWithReturn *notifier); 777 778 /** 779 * bdrv_detach_aio_context: 780 * 781 * May be called from .bdrv_detach_aio_context() to detach children from the 782 * current #AioContext. This is only needed by block drivers that manage their 783 * own children. Both ->file and ->backing are automatically handled and 784 * block drivers should not call this function on them explicitly. 785 */ 786 void bdrv_detach_aio_context(BlockDriverState *bs); 787 788 /** 789 * bdrv_attach_aio_context: 790 * 791 * May be called from .bdrv_attach_aio_context() to attach children to the new 792 * #AioContext. This is only needed by block drivers that manage their own 793 * children. Both ->file and ->backing are automatically handled and block 794 * drivers should not call this function on them explicitly. 795 */ 796 void bdrv_attach_aio_context(BlockDriverState *bs, 797 AioContext *new_context); 798 799 /** 800 * bdrv_add_aio_context_notifier: 801 * 802 * If a long-running job intends to be always run in the same AioContext as a 803 * certain BDS, it may use this function to be notified of changes regarding the 804 * association of the BDS to an AioContext. 805 * 806 * attached_aio_context() is called after the target BDS has been attached to a 807 * new AioContext; detach_aio_context() is called before the target BDS is being 808 * detached from its old AioContext. 809 */ 810 void bdrv_add_aio_context_notifier(BlockDriverState *bs, 811 void (*attached_aio_context)(AioContext *new_context, void *opaque), 812 void (*detach_aio_context)(void *opaque), void *opaque); 813 814 /** 815 * bdrv_remove_aio_context_notifier: 816 * 817 * Unsubscribe of change notifications regarding the BDS's AioContext. The 818 * parameters given here have to be the same as those given to 819 * bdrv_add_aio_context_notifier(). 820 */ 821 void bdrv_remove_aio_context_notifier(BlockDriverState *bs, 822 void (*aio_context_attached)(AioContext *, 823 void *), 824 void (*aio_context_detached)(void *), 825 void *opaque); 826 827 /** 828 * bdrv_wakeup: 829 * @bs: The BlockDriverState for which an I/O operation has been completed. 830 * 831 * Wake up the main thread if it is waiting on BDRV_POLL_WHILE. During 832 * synchronous I/O on a BlockDriverState that is attached to another 833 * I/O thread, the main thread lets the I/O thread's event loop run, 834 * waiting for the I/O operation to complete. A bdrv_wakeup will wake 835 * up the main thread if necessary. 836 * 837 * Manual calls to bdrv_wakeup are rarely necessary, because 838 * bdrv_dec_in_flight already calls it. 839 */ 840 void bdrv_wakeup(BlockDriverState *bs); 841 842 #ifdef _WIN32 843 int is_windows_drive(const char *filename); 844 #endif 845 846 /** 847 * stream_start: 848 * @job_id: The id of the newly-created job, or %NULL to use the 849 * device name of @bs. 850 * @bs: Block device to operate on. 851 * @base: Block device that will become the new base, or %NULL to 852 * flatten the whole backing file chain onto @bs. 853 * @backing_file_str: The file name that will be written to @bs as the 854 * the new backing file if the job completes. Ignored if @base is %NULL. 855 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 856 * @on_error: The action to take upon error. 857 * @errp: Error object. 858 * 859 * Start a streaming operation on @bs. Clusters that are unallocated 860 * in @bs, but allocated in any image between @base and @bs (both 861 * exclusive) will be written to @bs. At the end of a successful 862 * streaming job, the backing file of @bs will be changed to 863 * @backing_file_str in the written image and to @base in the live 864 * BlockDriverState. 865 */ 866 void stream_start(const char *job_id, BlockDriverState *bs, 867 BlockDriverState *base, const char *backing_file_str, 868 int64_t speed, BlockdevOnError on_error, Error **errp); 869 870 /** 871 * commit_start: 872 * @job_id: The id of the newly-created job, or %NULL to use the 873 * device name of @bs. 874 * @bs: Active block device. 875 * @top: Top block device to be committed. 876 * @base: Block device that will be written into, and become the new top. 877 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 878 * @on_error: The action to take upon error. 879 * @backing_file_str: String to use as the backing file in @top's overlay 880 * @filter_node_name: The node name that should be assigned to the filter 881 * driver that the commit job inserts into the graph above @top. NULL means 882 * that a node name should be autogenerated. 883 * @errp: Error object. 884 * 885 */ 886 void commit_start(const char *job_id, BlockDriverState *bs, 887 BlockDriverState *base, BlockDriverState *top, int64_t speed, 888 BlockdevOnError on_error, const char *backing_file_str, 889 const char *filter_node_name, Error **errp); 890 /** 891 * commit_active_start: 892 * @job_id: The id of the newly-created job, or %NULL to use the 893 * device name of @bs. 894 * @bs: Active block device to be committed. 895 * @base: Block device that will be written into, and become the new top. 896 * @creation_flags: Flags that control the behavior of the Job lifetime. 897 * See @BlockJobCreateFlags 898 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 899 * @on_error: The action to take upon error. 900 * @filter_node_name: The node name that should be assigned to the filter 901 * driver that the commit job inserts into the graph above @bs. NULL means that 902 * a node name should be autogenerated. 903 * @cb: Completion function for the job. 904 * @opaque: Opaque pointer value passed to @cb. 905 * @auto_complete: Auto complete the job. 906 * @errp: Error object. 907 * 908 */ 909 void commit_active_start(const char *job_id, BlockDriverState *bs, 910 BlockDriverState *base, int creation_flags, 911 int64_t speed, BlockdevOnError on_error, 912 const char *filter_node_name, 913 BlockCompletionFunc *cb, void *opaque, 914 bool auto_complete, Error **errp); 915 /* 916 * mirror_start: 917 * @job_id: The id of the newly-created job, or %NULL to use the 918 * device name of @bs. 919 * @bs: Block device to operate on. 920 * @target: Block device to write to. 921 * @replaces: Block graph node name to replace once the mirror is done. Can 922 * only be used when full mirroring is selected. 923 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 924 * @granularity: The chosen granularity for the dirty bitmap. 925 * @buf_size: The amount of data that can be in flight at one time. 926 * @mode: Whether to collapse all images in the chain to the target. 927 * @backing_mode: How to establish the target's backing chain after completion. 928 * @on_source_error: The action to take upon error reading from the source. 929 * @on_target_error: The action to take upon error writing to the target. 930 * @unmap: Whether to unmap target where source sectors only contain zeroes. 931 * @filter_node_name: The node name that should be assigned to the filter 932 * driver that the mirror job inserts into the graph above @bs. NULL means that 933 * a node name should be autogenerated. 934 * @errp: Error object. 935 * 936 * Start a mirroring operation on @bs. Clusters that are allocated 937 * in @bs will be written to @target until the job is cancelled or 938 * manually completed. At the end of a successful mirroring job, 939 * @bs will be switched to read from @target. 940 */ 941 void mirror_start(const char *job_id, BlockDriverState *bs, 942 BlockDriverState *target, const char *replaces, 943 int64_t speed, uint32_t granularity, int64_t buf_size, 944 MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, 945 BlockdevOnError on_source_error, 946 BlockdevOnError on_target_error, 947 bool unmap, const char *filter_node_name, Error **errp); 948 949 /* 950 * backup_job_create: 951 * @job_id: The id of the newly-created job, or %NULL to use the 952 * device name of @bs. 953 * @bs: Block device to operate on. 954 * @target: Block device to write to. 955 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 956 * @sync_mode: What parts of the disk image should be copied to the destination. 957 * @sync_bitmap: The dirty bitmap if sync_mode is MIRROR_SYNC_MODE_INCREMENTAL. 958 * @on_source_error: The action to take upon error reading from the source. 959 * @on_target_error: The action to take upon error writing to the target. 960 * @creation_flags: Flags that control the behavior of the Job lifetime. 961 * See @BlockJobCreateFlags 962 * @cb: Completion function for the job. 963 * @opaque: Opaque pointer value passed to @cb. 964 * @txn: Transaction that this job is part of (may be NULL). 965 * 966 * Create a backup operation on @bs. Clusters in @bs are written to @target 967 * until the job is cancelled or manually completed. 968 */ 969 BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, 970 BlockDriverState *target, int64_t speed, 971 MirrorSyncMode sync_mode, 972 BdrvDirtyBitmap *sync_bitmap, 973 bool compress, 974 BlockdevOnError on_source_error, 975 BlockdevOnError on_target_error, 976 int creation_flags, 977 BlockCompletionFunc *cb, void *opaque, 978 BlockJobTxn *txn, Error **errp); 979 980 void hmp_drive_add_node(Monitor *mon, const char *optstr); 981 982 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, 983 const char *child_name, 984 const BdrvChildRole *child_role, 985 uint64_t perm, uint64_t shared_perm, 986 void *opaque, Error **errp); 987 void bdrv_root_unref_child(BdrvChild *child); 988 989 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, 990 Error **errp); 991 992 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by 993 * block filters: Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED and RESIZE to 994 * all children */ 995 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c, 996 const BdrvChildRole *role, 997 BlockReopenQueue *reopen_queue, 998 uint64_t perm, uint64_t shared, 999 uint64_t *nperm, uint64_t *nshared); 1000 1001 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by 1002 * (non-raw) image formats: Like above for bs->backing, but for bs->file it 1003 * requires WRITE | RESIZE for read-write images, always requires 1004 * CONSISTENT_READ and doesn't share WRITE. */ 1005 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c, 1006 const BdrvChildRole *role, 1007 BlockReopenQueue *reopen_queue, 1008 uint64_t perm, uint64_t shared, 1009 uint64_t *nperm, uint64_t *nshared); 1010 1011 /* 1012 * Default implementation for drivers to pass bdrv_co_get_block_status() to 1013 * their file. 1014 */ 1015 int64_t coroutine_fn bdrv_co_get_block_status_from_file(BlockDriverState *bs, 1016 int64_t sector_num, 1017 int nb_sectors, 1018 int *pnum, 1019 BlockDriverState **file); 1020 /* 1021 * Default implementation for drivers to pass bdrv_co_get_block_status() to 1022 * their backing file. 1023 */ 1024 int64_t coroutine_fn bdrv_co_get_block_status_from_backing(BlockDriverState *bs, 1025 int64_t sector_num, 1026 int nb_sectors, 1027 int *pnum, 1028 BlockDriverState **file); 1029 const char *bdrv_get_parent_name(const BlockDriverState *bs); 1030 void blk_dev_change_media_cb(BlockBackend *blk, bool load, Error **errp); 1031 bool blk_dev_has_removable_media(BlockBackend *blk); 1032 bool blk_dev_has_tray(BlockBackend *blk); 1033 void blk_dev_eject_request(BlockBackend *blk, bool force); 1034 bool blk_dev_is_tray_open(BlockBackend *blk); 1035 bool blk_dev_is_medium_locked(BlockBackend *blk); 1036 1037 void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes); 1038 bool bdrv_requests_pending(BlockDriverState *bs); 1039 1040 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out); 1041 void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in); 1042 1043 void bdrv_inc_in_flight(BlockDriverState *bs); 1044 void bdrv_dec_in_flight(BlockDriverState *bs); 1045 1046 void blockdev_close_all_bdrv_states(void); 1047 1048 #endif /* BLOCK_INT_H */ 1049