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] and 206 * bdrv_is_allocated[_above]. The driver should answer only 207 * according to the current layer, and should not set 208 * BDRV_BLOCK_ALLOCATED, but may set BDRV_BLOCK_RAW. See block.h 209 * for the meaning of _DATA, _ZERO, and _OFFSET_VALID. The block 210 * layer guarantees input aligned to request_alignment, as well as 211 * non-NULL pnum and file. 212 */ 213 int64_t coroutine_fn (*bdrv_co_get_block_status)(BlockDriverState *bs, 214 int64_t sector_num, int nb_sectors, int *pnum, 215 BlockDriverState **file); 216 217 /* 218 * Invalidate any cached meta-data. 219 */ 220 void (*bdrv_invalidate_cache)(BlockDriverState *bs, Error **errp); 221 int (*bdrv_inactivate)(BlockDriverState *bs); 222 223 /* 224 * Flushes all data for all layers by calling bdrv_co_flush for underlying 225 * layers, if needed. This function is needed for deterministic 226 * synchronization of the flush finishing callback. 227 */ 228 int coroutine_fn (*bdrv_co_flush)(BlockDriverState *bs); 229 230 /* 231 * Flushes all data that was already written to the OS all the way down to 232 * the disk (for example file-posix.c calls fsync()). 233 */ 234 int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs); 235 236 /* 237 * Flushes all internal caches to the OS. The data may still sit in a 238 * writeback cache of the host OS, but it will survive a crash of the qemu 239 * process. 240 */ 241 int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs); 242 243 const char *protocol_name; 244 int (*bdrv_truncate)(BlockDriverState *bs, int64_t offset, 245 PreallocMode prealloc, Error **errp); 246 247 int64_t (*bdrv_getlength)(BlockDriverState *bs); 248 bool has_variable_length; 249 int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs); 250 BlockMeasureInfo *(*bdrv_measure)(QemuOpts *opts, BlockDriverState *in_bs, 251 Error **errp); 252 253 int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs, 254 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov); 255 256 int (*bdrv_snapshot_create)(BlockDriverState *bs, 257 QEMUSnapshotInfo *sn_info); 258 int (*bdrv_snapshot_goto)(BlockDriverState *bs, 259 const char *snapshot_id); 260 int (*bdrv_snapshot_delete)(BlockDriverState *bs, 261 const char *snapshot_id, 262 const char *name, 263 Error **errp); 264 int (*bdrv_snapshot_list)(BlockDriverState *bs, 265 QEMUSnapshotInfo **psn_info); 266 int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs, 267 const char *snapshot_id, 268 const char *name, 269 Error **errp); 270 int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi); 271 ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs); 272 273 int coroutine_fn (*bdrv_save_vmstate)(BlockDriverState *bs, 274 QEMUIOVector *qiov, 275 int64_t pos); 276 int coroutine_fn (*bdrv_load_vmstate)(BlockDriverState *bs, 277 QEMUIOVector *qiov, 278 int64_t pos); 279 280 int (*bdrv_change_backing_file)(BlockDriverState *bs, 281 const char *backing_file, const char *backing_fmt); 282 283 /* removable device specific */ 284 bool (*bdrv_is_inserted)(BlockDriverState *bs); 285 void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag); 286 void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked); 287 288 /* to control generic scsi devices */ 289 BlockAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs, 290 unsigned long int req, void *buf, 291 BlockCompletionFunc *cb, void *opaque); 292 int coroutine_fn (*bdrv_co_ioctl)(BlockDriverState *bs, 293 unsigned long int req, void *buf); 294 295 /* List of options for creating images, terminated by name == NULL */ 296 QemuOptsList *create_opts; 297 298 /* 299 * Returns 0 for completed check, -errno for internal errors. 300 * The check results are stored in result. 301 */ 302 int (*bdrv_check)(BlockDriverState *bs, BdrvCheckResult *result, 303 BdrvCheckMode fix); 304 305 int (*bdrv_amend_options)(BlockDriverState *bs, QemuOpts *opts, 306 BlockDriverAmendStatusCB *status_cb, 307 void *cb_opaque); 308 309 void (*bdrv_debug_event)(BlockDriverState *bs, BlkdebugEvent event); 310 311 /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */ 312 int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event, 313 const char *tag); 314 int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs, 315 const char *tag); 316 int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag); 317 bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag); 318 319 void (*bdrv_refresh_limits)(BlockDriverState *bs, Error **errp); 320 321 /* 322 * Returns 1 if newly created images are guaranteed to contain only 323 * zeros, 0 otherwise. 324 */ 325 int (*bdrv_has_zero_init)(BlockDriverState *bs); 326 327 /* Remove fd handlers, timers, and other event loop callbacks so the event 328 * loop is no longer in use. Called with no in-flight requests and in 329 * depth-first traversal order with parents before child nodes. 330 */ 331 void (*bdrv_detach_aio_context)(BlockDriverState *bs); 332 333 /* Add fd handlers, timers, and other event loop callbacks so I/O requests 334 * can be processed again. Called with no in-flight requests and in 335 * depth-first traversal order with child nodes before parent nodes. 336 */ 337 void (*bdrv_attach_aio_context)(BlockDriverState *bs, 338 AioContext *new_context); 339 340 /* io queue for linux-aio */ 341 void (*bdrv_io_plug)(BlockDriverState *bs); 342 void (*bdrv_io_unplug)(BlockDriverState *bs); 343 344 /** 345 * Try to get @bs's logical and physical block size. 346 * On success, store them in @bsz and return zero. 347 * On failure, return negative errno. 348 */ 349 int (*bdrv_probe_blocksizes)(BlockDriverState *bs, BlockSizes *bsz); 350 /** 351 * Try to get @bs's geometry (cyls, heads, sectors) 352 * On success, store them in @geo and return 0. 353 * On failure return -errno. 354 * Only drivers that want to override guest geometry implement this 355 * callback; see hd_geometry_guess(). 356 */ 357 int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo); 358 359 /** 360 * bdrv_co_drain_begin is called if implemented in the beginning of a 361 * drain operation to drain and stop any internal sources of requests in 362 * the driver. 363 * bdrv_co_drain_end is called if implemented at the end of the drain. 364 * 365 * They should be used by the driver to e.g. manage scheduled I/O 366 * requests, or toggle an internal state. After the end of the drain new 367 * requests will continue normally. 368 */ 369 void coroutine_fn (*bdrv_co_drain_begin)(BlockDriverState *bs); 370 void coroutine_fn (*bdrv_co_drain_end)(BlockDriverState *bs); 371 372 void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child, 373 Error **errp); 374 void (*bdrv_del_child)(BlockDriverState *parent, BdrvChild *child, 375 Error **errp); 376 377 /** 378 * Informs the block driver that a permission change is intended. The 379 * driver checks whether the change is permissible and may take other 380 * preparations for the change (e.g. get file system locks). This operation 381 * is always followed either by a call to either .bdrv_set_perm or 382 * .bdrv_abort_perm_update. 383 * 384 * Checks whether the requested set of cumulative permissions in @perm 385 * can be granted for accessing @bs and whether no other users are using 386 * permissions other than those given in @shared (both arguments take 387 * BLK_PERM_* bitmasks). 388 * 389 * If both conditions are met, 0 is returned. Otherwise, -errno is returned 390 * and errp is set to an error describing the conflict. 391 */ 392 int (*bdrv_check_perm)(BlockDriverState *bs, uint64_t perm, 393 uint64_t shared, Error **errp); 394 395 /** 396 * Called to inform the driver that the set of cumulative set of used 397 * permissions for @bs has changed to @perm, and the set of sharable 398 * permission to @shared. The driver can use this to propagate changes to 399 * its children (i.e. request permissions only if a parent actually needs 400 * them). 401 * 402 * This function is only invoked after bdrv_check_perm(), so block drivers 403 * may rely on preparations made in their .bdrv_check_perm implementation. 404 */ 405 void (*bdrv_set_perm)(BlockDriverState *bs, uint64_t perm, uint64_t shared); 406 407 /* 408 * Called to inform the driver that after a previous bdrv_check_perm() 409 * call, the permission update is not performed and any preparations made 410 * for it (e.g. taken file locks) need to be undone. 411 * 412 * This function can be called even for nodes that never saw a 413 * bdrv_check_perm() call. It is a no-op then. 414 */ 415 void (*bdrv_abort_perm_update)(BlockDriverState *bs); 416 417 /** 418 * Returns in @nperm and @nshared the permissions that the driver for @bs 419 * needs on its child @c, based on the cumulative permissions requested by 420 * the parents in @parent_perm and @parent_shared. 421 * 422 * If @c is NULL, return the permissions for attaching a new child for the 423 * given @role. 424 * 425 * If @reopen_queue is non-NULL, don't return the currently needed 426 * permissions, but those that will be needed after applying the 427 * @reopen_queue. 428 */ 429 void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c, 430 const BdrvChildRole *role, 431 BlockReopenQueue *reopen_queue, 432 uint64_t parent_perm, uint64_t parent_shared, 433 uint64_t *nperm, uint64_t *nshared); 434 435 /** 436 * Bitmaps should be marked as 'IN_USE' in the image on reopening image 437 * as rw. This handler should realize it. It also should unset readonly 438 * field of BlockDirtyBitmap's in case of success. 439 */ 440 int (*bdrv_reopen_bitmaps_rw)(BlockDriverState *bs, Error **errp); 441 bool (*bdrv_can_store_new_dirty_bitmap)(BlockDriverState *bs, 442 const char *name, 443 uint32_t granularity, 444 Error **errp); 445 void (*bdrv_remove_persistent_dirty_bitmap)(BlockDriverState *bs, 446 const char *name, 447 Error **errp); 448 449 QLIST_ENTRY(BlockDriver) list; 450 }; 451 452 typedef struct BlockLimits { 453 /* Alignment requirement, in bytes, for offset/length of I/O 454 * requests. Must be a power of 2 less than INT_MAX; defaults to 455 * 1 for drivers with modern byte interfaces, and to 512 456 * otherwise. */ 457 uint32_t request_alignment; 458 459 /* Maximum number of bytes that can be discarded at once (since it 460 * is signed, it must be < 2G, if set). Must be multiple of 461 * pdiscard_alignment, but need not be power of 2. May be 0 if no 462 * inherent 32-bit limit */ 463 int32_t max_pdiscard; 464 465 /* Optimal alignment for discard requests in bytes. A power of 2 466 * is best but not mandatory. Must be a multiple of 467 * bl.request_alignment, and must be less than max_pdiscard if 468 * that is set. May be 0 if bl.request_alignment is good enough */ 469 uint32_t pdiscard_alignment; 470 471 /* Maximum number of bytes that can zeroized at once (since it is 472 * signed, it must be < 2G, if set). Must be multiple of 473 * pwrite_zeroes_alignment. May be 0 if no inherent 32-bit limit */ 474 int32_t max_pwrite_zeroes; 475 476 /* Optimal alignment for write zeroes requests in bytes. A power 477 * of 2 is best but not mandatory. Must be a multiple of 478 * bl.request_alignment, and must be less than max_pwrite_zeroes 479 * if that is set. May be 0 if bl.request_alignment is good 480 * enough */ 481 uint32_t pwrite_zeroes_alignment; 482 483 /* Optimal transfer length in bytes. A power of 2 is best but not 484 * mandatory. Must be a multiple of bl.request_alignment, or 0 if 485 * no preferred size */ 486 uint32_t opt_transfer; 487 488 /* Maximal transfer length in bytes. Need not be power of 2, but 489 * must be multiple of opt_transfer and bl.request_alignment, or 0 490 * for no 32-bit limit. For now, anything larger than INT_MAX is 491 * clamped down. */ 492 uint32_t max_transfer; 493 494 /* memory alignment, in bytes so that no bounce buffer is needed */ 495 size_t min_mem_alignment; 496 497 /* memory alignment, in bytes, for bounce buffer */ 498 size_t opt_mem_alignment; 499 500 /* maximum number of iovec elements */ 501 int max_iov; 502 } BlockLimits; 503 504 typedef struct BdrvOpBlocker BdrvOpBlocker; 505 506 typedef struct BdrvAioNotifier { 507 void (*attached_aio_context)(AioContext *new_context, void *opaque); 508 void (*detach_aio_context)(void *opaque); 509 510 void *opaque; 511 bool deleted; 512 513 QLIST_ENTRY(BdrvAioNotifier) list; 514 } BdrvAioNotifier; 515 516 struct BdrvChildRole { 517 /* If true, bdrv_replace_node() doesn't change the node this BdrvChild 518 * points to. */ 519 bool stay_at_node; 520 521 void (*inherit_options)(int *child_flags, QDict *child_options, 522 int parent_flags, QDict *parent_options); 523 524 void (*change_media)(BdrvChild *child, bool load); 525 void (*resize)(BdrvChild *child); 526 527 /* Returns a name that is supposedly more useful for human users than the 528 * node name for identifying the node in question (in particular, a BB 529 * name), or NULL if the parent can't provide a better name. */ 530 const char *(*get_name)(BdrvChild *child); 531 532 /* Returns a malloced string that describes the parent of the child for a 533 * human reader. This could be a node-name, BlockBackend name, qdev ID or 534 * QOM path of the device owning the BlockBackend, job type and ID etc. The 535 * caller is responsible for freeing the memory. */ 536 char *(*get_parent_desc)(BdrvChild *child); 537 538 /* 539 * If this pair of functions is implemented, the parent doesn't issue new 540 * requests after returning from .drained_begin() until .drained_end() is 541 * called. 542 * 543 * Note that this can be nested. If drained_begin() was called twice, new 544 * I/O is allowed only after drained_end() was called twice, too. 545 */ 546 void (*drained_begin)(BdrvChild *child); 547 void (*drained_end)(BdrvChild *child); 548 549 /* Notifies the parent that the child has been activated/inactivated (e.g. 550 * when migration is completing) and it can start/stop requesting 551 * permissions and doing I/O on it. */ 552 void (*activate)(BdrvChild *child, Error **errp); 553 int (*inactivate)(BdrvChild *child); 554 555 void (*attach)(BdrvChild *child); 556 void (*detach)(BdrvChild *child); 557 558 /* Notifies the parent that the filename of its child has changed (e.g. 559 * because the direct child was removed from the backing chain), so that it 560 * can update its reference. */ 561 int (*update_filename)(BdrvChild *child, BlockDriverState *new_base, 562 const char *filename, Error **errp); 563 }; 564 565 extern const BdrvChildRole child_file; 566 extern const BdrvChildRole child_format; 567 extern const BdrvChildRole child_backing; 568 569 struct BdrvChild { 570 BlockDriverState *bs; 571 char *name; 572 const BdrvChildRole *role; 573 void *opaque; 574 575 /** 576 * Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask) 577 */ 578 uint64_t perm; 579 580 /** 581 * Permissions that can still be granted to other users of @bs while this 582 * BdrvChild is still attached to it. (BLK_PERM_* bitmask) 583 */ 584 uint64_t shared_perm; 585 586 QLIST_ENTRY(BdrvChild) next; 587 QLIST_ENTRY(BdrvChild) next_parent; 588 }; 589 590 /* 591 * Note: the function bdrv_append() copies and swaps contents of 592 * BlockDriverStates, so if you add new fields to this struct, please 593 * inspect bdrv_append() to determine if the new fields need to be 594 * copied as well. 595 */ 596 struct BlockDriverState { 597 /* Protected by big QEMU lock or read-only after opening. No special 598 * locking needed during I/O... 599 */ 600 int open_flags; /* flags used to open the file, re-used for re-open */ 601 bool read_only; /* if true, the media is read only */ 602 bool encrypted; /* if true, the media is encrypted */ 603 bool sg; /* if true, the device is a /dev/sg* */ 604 bool probed; /* if true, format was probed rather than specified */ 605 bool force_share; /* if true, always allow all shared permissions */ 606 bool implicit; /* if true, this filter node was automatically inserted */ 607 608 BlockDriver *drv; /* NULL means no media */ 609 void *opaque; 610 611 AioContext *aio_context; /* event loop used for fd handlers, timers, etc */ 612 /* long-running tasks intended to always use the same AioContext as this 613 * BDS may register themselves in this list to be notified of changes 614 * regarding this BDS's context */ 615 QLIST_HEAD(, BdrvAioNotifier) aio_notifiers; 616 bool walking_aio_notifiers; /* to make removal during iteration safe */ 617 618 char filename[PATH_MAX]; 619 char backing_file[PATH_MAX]; /* if non zero, the image is a diff of 620 this file image */ 621 char backing_format[16]; /* if non-zero and backing_file exists */ 622 623 QDict *full_open_options; 624 char exact_filename[PATH_MAX]; 625 626 BdrvChild *backing; 627 BdrvChild *file; 628 629 /* I/O Limits */ 630 BlockLimits bl; 631 632 /* Flags honored during pwrite (so far: BDRV_REQ_FUA) */ 633 unsigned int supported_write_flags; 634 /* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA, 635 * BDRV_REQ_MAY_UNMAP) */ 636 unsigned int supported_zero_flags; 637 638 /* the following member gives a name to every node on the bs graph. */ 639 char node_name[32]; 640 /* element of the list of named nodes building the graph */ 641 QTAILQ_ENTRY(BlockDriverState) node_list; 642 /* element of the list of all BlockDriverStates (all_bdrv_states) */ 643 QTAILQ_ENTRY(BlockDriverState) bs_list; 644 /* element of the list of monitor-owned BDS */ 645 QTAILQ_ENTRY(BlockDriverState) monitor_list; 646 int refcnt; 647 648 /* operation blockers */ 649 QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; 650 651 /* long-running background operation */ 652 BlockJob *job; 653 654 /* The node that this node inherited default options from (and a reopen on 655 * which can affect this node by changing these defaults). This is always a 656 * parent node of this node. */ 657 BlockDriverState *inherits_from; 658 QLIST_HEAD(, BdrvChild) children; 659 QLIST_HEAD(, BdrvChild) parents; 660 661 QDict *options; 662 QDict *explicit_options; 663 BlockdevDetectZeroesOptions detect_zeroes; 664 665 /* The error object in use for blocking operations on backing_hd */ 666 Error *backing_blocker; 667 668 /* Protected by AioContext lock */ 669 670 /* If we are reading a disk image, give its size in sectors. 671 * Generally read-only; it is written to by load_snapshot and 672 * save_snaphost, but the block layer is quiescent during those. 673 */ 674 int64_t total_sectors; 675 676 /* Callback before write request is processed */ 677 NotifierWithReturnList before_write_notifiers; 678 679 /* threshold limit for writes, in bytes. "High water mark". */ 680 uint64_t write_threshold_offset; 681 NotifierWithReturn write_threshold_notifier; 682 683 /* Writing to the list requires the BQL _and_ the dirty_bitmap_mutex. 684 * Reading from the list can be done with either the BQL or the 685 * dirty_bitmap_mutex. Modifying a bitmap only requires 686 * dirty_bitmap_mutex. */ 687 QemuMutex dirty_bitmap_mutex; 688 QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps; 689 690 /* Offset after the highest byte written to */ 691 Stat64 wr_highest_offset; 692 693 /* If true, copy read backing sectors into image. Can be >1 if more 694 * than one client has requested copy-on-read. Accessed with atomic 695 * ops. 696 */ 697 int copy_on_read; 698 699 /* number of in-flight requests; overall and serialising. 700 * Accessed with atomic ops. 701 */ 702 unsigned int in_flight; 703 unsigned int serialising_in_flight; 704 705 /* Internal to BDRV_POLL_WHILE and bdrv_wakeup. Accessed with atomic 706 * ops. 707 */ 708 bool wakeup; 709 710 /* counter for nested bdrv_io_plug. 711 * Accessed with atomic ops. 712 */ 713 unsigned io_plugged; 714 715 /* do we need to tell the quest if we have a volatile write cache? */ 716 int enable_write_cache; 717 718 /* Accessed with atomic ops. */ 719 int quiesce_counter; 720 int recursive_quiesce_counter; 721 722 unsigned int write_gen; /* Current data generation */ 723 724 /* Protected by reqs_lock. */ 725 CoMutex reqs_lock; 726 QLIST_HEAD(, BdrvTrackedRequest) tracked_requests; 727 CoQueue flush_queue; /* Serializing flush queue */ 728 bool active_flush_req; /* Flush request in flight? */ 729 730 /* Only read/written by whoever has set active_flush_req to true. */ 731 unsigned int flushed_gen; /* Flushed write generation */ 732 }; 733 734 struct BlockBackendRootState { 735 int open_flags; 736 bool read_only; 737 BlockdevDetectZeroesOptions detect_zeroes; 738 }; 739 740 typedef enum BlockMirrorBackingMode { 741 /* Reuse the existing backing chain from the source for the target. 742 * - sync=full: Set backing BDS to NULL. 743 * - sync=top: Use source's backing BDS. 744 * - sync=none: Use source as the backing BDS. */ 745 MIRROR_SOURCE_BACKING_CHAIN, 746 747 /* Open the target's backing chain completely anew */ 748 MIRROR_OPEN_BACKING_CHAIN, 749 750 /* Do not change the target's backing BDS after job completion */ 751 MIRROR_LEAVE_BACKING_CHAIN, 752 } BlockMirrorBackingMode; 753 754 static inline BlockDriverState *backing_bs(BlockDriverState *bs) 755 { 756 return bs->backing ? bs->backing->bs : NULL; 757 } 758 759 760 /* Essential block drivers which must always be statically linked into qemu, and 761 * which therefore can be accessed without using bdrv_find_format() */ 762 extern BlockDriver bdrv_file; 763 extern BlockDriver bdrv_raw; 764 extern BlockDriver bdrv_qcow2; 765 766 int coroutine_fn bdrv_co_preadv(BdrvChild *child, 767 int64_t offset, unsigned int bytes, QEMUIOVector *qiov, 768 BdrvRequestFlags flags); 769 int coroutine_fn bdrv_co_pwritev(BdrvChild *child, 770 int64_t offset, unsigned int bytes, QEMUIOVector *qiov, 771 BdrvRequestFlags flags); 772 773 void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent); 774 void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent); 775 776 int get_tmp_filename(char *filename, int size); 777 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size, 778 const char *filename); 779 780 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, 781 QDict *options); 782 783 784 /** 785 * bdrv_add_before_write_notifier: 786 * 787 * Register a callback that is invoked before write requests are processed but 788 * after any throttling or waiting for overlapping requests. 789 */ 790 void bdrv_add_before_write_notifier(BlockDriverState *bs, 791 NotifierWithReturn *notifier); 792 793 /** 794 * bdrv_detach_aio_context: 795 * 796 * May be called from .bdrv_detach_aio_context() to detach children from the 797 * current #AioContext. This is only needed by block drivers that manage their 798 * own children. Both ->file and ->backing are automatically handled and 799 * block drivers should not call this function on them explicitly. 800 */ 801 void bdrv_detach_aio_context(BlockDriverState *bs); 802 803 /** 804 * bdrv_attach_aio_context: 805 * 806 * May be called from .bdrv_attach_aio_context() to attach children to the new 807 * #AioContext. This is only needed by block drivers that manage their own 808 * children. Both ->file and ->backing are automatically handled and block 809 * drivers should not call this function on them explicitly. 810 */ 811 void bdrv_attach_aio_context(BlockDriverState *bs, 812 AioContext *new_context); 813 814 /** 815 * bdrv_add_aio_context_notifier: 816 * 817 * If a long-running job intends to be always run in the same AioContext as a 818 * certain BDS, it may use this function to be notified of changes regarding the 819 * association of the BDS to an AioContext. 820 * 821 * attached_aio_context() is called after the target BDS has been attached to a 822 * new AioContext; detach_aio_context() is called before the target BDS is being 823 * detached from its old AioContext. 824 */ 825 void bdrv_add_aio_context_notifier(BlockDriverState *bs, 826 void (*attached_aio_context)(AioContext *new_context, void *opaque), 827 void (*detach_aio_context)(void *opaque), void *opaque); 828 829 /** 830 * bdrv_remove_aio_context_notifier: 831 * 832 * Unsubscribe of change notifications regarding the BDS's AioContext. The 833 * parameters given here have to be the same as those given to 834 * bdrv_add_aio_context_notifier(). 835 */ 836 void bdrv_remove_aio_context_notifier(BlockDriverState *bs, 837 void (*aio_context_attached)(AioContext *, 838 void *), 839 void (*aio_context_detached)(void *), 840 void *opaque); 841 842 /** 843 * bdrv_wakeup: 844 * @bs: The BlockDriverState for which an I/O operation has been completed. 845 * 846 * Wake up the main thread if it is waiting on BDRV_POLL_WHILE. During 847 * synchronous I/O on a BlockDriverState that is attached to another 848 * I/O thread, the main thread lets the I/O thread's event loop run, 849 * waiting for the I/O operation to complete. A bdrv_wakeup will wake 850 * up the main thread if necessary. 851 * 852 * Manual calls to bdrv_wakeup are rarely necessary, because 853 * bdrv_dec_in_flight already calls it. 854 */ 855 void bdrv_wakeup(BlockDriverState *bs); 856 857 #ifdef _WIN32 858 int is_windows_drive(const char *filename); 859 #endif 860 861 /** 862 * stream_start: 863 * @job_id: The id of the newly-created job, or %NULL to use the 864 * device name of @bs. 865 * @bs: Block device to operate on. 866 * @base: Block device that will become the new base, or %NULL to 867 * flatten the whole backing file chain onto @bs. 868 * @backing_file_str: The file name that will be written to @bs as the 869 * the new backing file if the job completes. Ignored if @base is %NULL. 870 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 871 * @on_error: The action to take upon error. 872 * @errp: Error object. 873 * 874 * Start a streaming operation on @bs. Clusters that are unallocated 875 * in @bs, but allocated in any image between @base and @bs (both 876 * exclusive) will be written to @bs. At the end of a successful 877 * streaming job, the backing file of @bs will be changed to 878 * @backing_file_str in the written image and to @base in the live 879 * BlockDriverState. 880 */ 881 void stream_start(const char *job_id, BlockDriverState *bs, 882 BlockDriverState *base, const char *backing_file_str, 883 int64_t speed, BlockdevOnError on_error, Error **errp); 884 885 /** 886 * commit_start: 887 * @job_id: The id of the newly-created job, or %NULL to use the 888 * device name of @bs. 889 * @bs: Active block device. 890 * @top: Top block device to be committed. 891 * @base: Block device that will be written into, and become the new top. 892 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 893 * @on_error: The action to take upon error. 894 * @backing_file_str: String to use as the backing file in @top's overlay 895 * @filter_node_name: The node name that should be assigned to the filter 896 * driver that the commit job inserts into the graph above @top. NULL means 897 * that a node name should be autogenerated. 898 * @errp: Error object. 899 * 900 */ 901 void commit_start(const char *job_id, BlockDriverState *bs, 902 BlockDriverState *base, BlockDriverState *top, int64_t speed, 903 BlockdevOnError on_error, const char *backing_file_str, 904 const char *filter_node_name, Error **errp); 905 /** 906 * commit_active_start: 907 * @job_id: The id of the newly-created job, or %NULL to use the 908 * device name of @bs. 909 * @bs: Active block device to be committed. 910 * @base: Block device that will be written into, and become the new top. 911 * @creation_flags: Flags that control the behavior of the Job lifetime. 912 * See @BlockJobCreateFlags 913 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 914 * @on_error: The action to take upon error. 915 * @filter_node_name: The node name that should be assigned to the filter 916 * driver that the commit job inserts into the graph above @bs. NULL means that 917 * a node name should be autogenerated. 918 * @cb: Completion function for the job. 919 * @opaque: Opaque pointer value passed to @cb. 920 * @auto_complete: Auto complete the job. 921 * @errp: Error object. 922 * 923 */ 924 void commit_active_start(const char *job_id, BlockDriverState *bs, 925 BlockDriverState *base, int creation_flags, 926 int64_t speed, BlockdevOnError on_error, 927 const char *filter_node_name, 928 BlockCompletionFunc *cb, void *opaque, 929 bool auto_complete, Error **errp); 930 /* 931 * mirror_start: 932 * @job_id: The id of the newly-created job, or %NULL to use the 933 * device name of @bs. 934 * @bs: Block device to operate on. 935 * @target: Block device to write to. 936 * @replaces: Block graph node name to replace once the mirror is done. Can 937 * only be used when full mirroring is selected. 938 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 939 * @granularity: The chosen granularity for the dirty bitmap. 940 * @buf_size: The amount of data that can be in flight at one time. 941 * @mode: Whether to collapse all images in the chain to the target. 942 * @backing_mode: How to establish the target's backing chain after completion. 943 * @on_source_error: The action to take upon error reading from the source. 944 * @on_target_error: The action to take upon error writing to the target. 945 * @unmap: Whether to unmap target where source sectors only contain zeroes. 946 * @filter_node_name: The node name that should be assigned to the filter 947 * driver that the mirror job inserts into the graph above @bs. NULL means that 948 * a node name should be autogenerated. 949 * @errp: Error object. 950 * 951 * Start a mirroring operation on @bs. Clusters that are allocated 952 * in @bs will be written to @target until the job is cancelled or 953 * manually completed. At the end of a successful mirroring job, 954 * @bs will be switched to read from @target. 955 */ 956 void mirror_start(const char *job_id, BlockDriverState *bs, 957 BlockDriverState *target, const char *replaces, 958 int64_t speed, uint32_t granularity, int64_t buf_size, 959 MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, 960 BlockdevOnError on_source_error, 961 BlockdevOnError on_target_error, 962 bool unmap, const char *filter_node_name, Error **errp); 963 964 /* 965 * backup_job_create: 966 * @job_id: The id of the newly-created job, or %NULL to use the 967 * device name of @bs. 968 * @bs: Block device to operate on. 969 * @target: Block device to write to. 970 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 971 * @sync_mode: What parts of the disk image should be copied to the destination. 972 * @sync_bitmap: The dirty bitmap if sync_mode is MIRROR_SYNC_MODE_INCREMENTAL. 973 * @on_source_error: The action to take upon error reading from the source. 974 * @on_target_error: The action to take upon error writing to the target. 975 * @creation_flags: Flags that control the behavior of the Job lifetime. 976 * See @BlockJobCreateFlags 977 * @cb: Completion function for the job. 978 * @opaque: Opaque pointer value passed to @cb. 979 * @txn: Transaction that this job is part of (may be NULL). 980 * 981 * Create a backup operation on @bs. Clusters in @bs are written to @target 982 * until the job is cancelled or manually completed. 983 */ 984 BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, 985 BlockDriverState *target, int64_t speed, 986 MirrorSyncMode sync_mode, 987 BdrvDirtyBitmap *sync_bitmap, 988 bool compress, 989 BlockdevOnError on_source_error, 990 BlockdevOnError on_target_error, 991 int creation_flags, 992 BlockCompletionFunc *cb, void *opaque, 993 BlockJobTxn *txn, Error **errp); 994 995 void hmp_drive_add_node(Monitor *mon, const char *optstr); 996 997 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, 998 const char *child_name, 999 const BdrvChildRole *child_role, 1000 uint64_t perm, uint64_t shared_perm, 1001 void *opaque, Error **errp); 1002 void bdrv_root_unref_child(BdrvChild *child); 1003 1004 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, 1005 Error **errp); 1006 1007 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by 1008 * block filters: Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED and RESIZE to 1009 * all children */ 1010 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c, 1011 const BdrvChildRole *role, 1012 BlockReopenQueue *reopen_queue, 1013 uint64_t perm, uint64_t shared, 1014 uint64_t *nperm, uint64_t *nshared); 1015 1016 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by 1017 * (non-raw) image formats: Like above for bs->backing, but for bs->file it 1018 * requires WRITE | RESIZE for read-write images, always requires 1019 * CONSISTENT_READ and doesn't share WRITE. */ 1020 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c, 1021 const BdrvChildRole *role, 1022 BlockReopenQueue *reopen_queue, 1023 uint64_t perm, uint64_t shared, 1024 uint64_t *nperm, uint64_t *nshared); 1025 1026 /* 1027 * Default implementation for drivers to pass bdrv_co_get_block_status() to 1028 * their file. 1029 */ 1030 int64_t coroutine_fn bdrv_co_get_block_status_from_file(BlockDriverState *bs, 1031 int64_t sector_num, 1032 int nb_sectors, 1033 int *pnum, 1034 BlockDriverState **file); 1035 /* 1036 * Default implementation for drivers to pass bdrv_co_get_block_status() to 1037 * their backing file. 1038 */ 1039 int64_t coroutine_fn bdrv_co_get_block_status_from_backing(BlockDriverState *bs, 1040 int64_t sector_num, 1041 int nb_sectors, 1042 int *pnum, 1043 BlockDriverState **file); 1044 const char *bdrv_get_parent_name(const BlockDriverState *bs); 1045 void blk_dev_change_media_cb(BlockBackend *blk, bool load, Error **errp); 1046 bool blk_dev_has_removable_media(BlockBackend *blk); 1047 bool blk_dev_has_tray(BlockBackend *blk); 1048 void blk_dev_eject_request(BlockBackend *blk, bool force); 1049 bool blk_dev_is_tray_open(BlockBackend *blk); 1050 bool blk_dev_is_medium_locked(BlockBackend *blk); 1051 1052 void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes); 1053 1054 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out); 1055 void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in); 1056 1057 void bdrv_inc_in_flight(BlockDriverState *bs); 1058 void bdrv_dec_in_flight(BlockDriverState *bs); 1059 1060 void blockdev_close_all_bdrv_states(void); 1061 1062 #endif /* BLOCK_INT_H */ 1063