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 /** 450 * Register/unregister a buffer for I/O. For example, when the driver is 451 * interested to know the memory areas that will later be used in iovs, so 452 * that it can do IOMMU mapping with VFIO etc., in order to get better 453 * performance. In the case of VFIO drivers, this callback is used to do 454 * DMA mapping for hot buffers. 455 */ 456 void (*bdrv_register_buf)(BlockDriverState *bs, void *host, size_t size); 457 void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host); 458 QLIST_ENTRY(BlockDriver) list; 459 }; 460 461 typedef struct BlockLimits { 462 /* Alignment requirement, in bytes, for offset/length of I/O 463 * requests. Must be a power of 2 less than INT_MAX; defaults to 464 * 1 for drivers with modern byte interfaces, and to 512 465 * otherwise. */ 466 uint32_t request_alignment; 467 468 /* Maximum number of bytes that can be discarded at once (since it 469 * is signed, it must be < 2G, if set). Must be multiple of 470 * pdiscard_alignment, but need not be power of 2. May be 0 if no 471 * inherent 32-bit limit */ 472 int32_t max_pdiscard; 473 474 /* Optimal alignment for discard requests in bytes. A power of 2 475 * is best but not mandatory. Must be a multiple of 476 * bl.request_alignment, and must be less than max_pdiscard if 477 * that is set. May be 0 if bl.request_alignment is good enough */ 478 uint32_t pdiscard_alignment; 479 480 /* Maximum number of bytes that can zeroized at once (since it is 481 * signed, it must be < 2G, if set). Must be multiple of 482 * pwrite_zeroes_alignment. May be 0 if no inherent 32-bit limit */ 483 int32_t max_pwrite_zeroes; 484 485 /* Optimal alignment for write zeroes requests in bytes. A power 486 * of 2 is best but not mandatory. Must be a multiple of 487 * bl.request_alignment, and must be less than max_pwrite_zeroes 488 * if that is set. May be 0 if bl.request_alignment is good 489 * enough */ 490 uint32_t pwrite_zeroes_alignment; 491 492 /* Optimal transfer length in bytes. A power of 2 is best but not 493 * mandatory. Must be a multiple of bl.request_alignment, or 0 if 494 * no preferred size */ 495 uint32_t opt_transfer; 496 497 /* Maximal transfer length in bytes. Need not be power of 2, but 498 * must be multiple of opt_transfer and bl.request_alignment, or 0 499 * for no 32-bit limit. For now, anything larger than INT_MAX is 500 * clamped down. */ 501 uint32_t max_transfer; 502 503 /* memory alignment, in bytes so that no bounce buffer is needed */ 504 size_t min_mem_alignment; 505 506 /* memory alignment, in bytes, for bounce buffer */ 507 size_t opt_mem_alignment; 508 509 /* maximum number of iovec elements */ 510 int max_iov; 511 } BlockLimits; 512 513 typedef struct BdrvOpBlocker BdrvOpBlocker; 514 515 typedef struct BdrvAioNotifier { 516 void (*attached_aio_context)(AioContext *new_context, void *opaque); 517 void (*detach_aio_context)(void *opaque); 518 519 void *opaque; 520 bool deleted; 521 522 QLIST_ENTRY(BdrvAioNotifier) list; 523 } BdrvAioNotifier; 524 525 struct BdrvChildRole { 526 /* If true, bdrv_replace_node() doesn't change the node this BdrvChild 527 * points to. */ 528 bool stay_at_node; 529 530 void (*inherit_options)(int *child_flags, QDict *child_options, 531 int parent_flags, QDict *parent_options); 532 533 void (*change_media)(BdrvChild *child, bool load); 534 void (*resize)(BdrvChild *child); 535 536 /* Returns a name that is supposedly more useful for human users than the 537 * node name for identifying the node in question (in particular, a BB 538 * name), or NULL if the parent can't provide a better name. */ 539 const char *(*get_name)(BdrvChild *child); 540 541 /* Returns a malloced string that describes the parent of the child for a 542 * human reader. This could be a node-name, BlockBackend name, qdev ID or 543 * QOM path of the device owning the BlockBackend, job type and ID etc. The 544 * caller is responsible for freeing the memory. */ 545 char *(*get_parent_desc)(BdrvChild *child); 546 547 /* 548 * If this pair of functions is implemented, the parent doesn't issue new 549 * requests after returning from .drained_begin() until .drained_end() is 550 * called. 551 * 552 * Note that this can be nested. If drained_begin() was called twice, new 553 * I/O is allowed only after drained_end() was called twice, too. 554 */ 555 void (*drained_begin)(BdrvChild *child); 556 void (*drained_end)(BdrvChild *child); 557 558 /* Notifies the parent that the child has been activated/inactivated (e.g. 559 * when migration is completing) and it can start/stop requesting 560 * permissions and doing I/O on it. */ 561 void (*activate)(BdrvChild *child, Error **errp); 562 int (*inactivate)(BdrvChild *child); 563 564 void (*attach)(BdrvChild *child); 565 void (*detach)(BdrvChild *child); 566 567 /* Notifies the parent that the filename of its child has changed (e.g. 568 * because the direct child was removed from the backing chain), so that it 569 * can update its reference. */ 570 int (*update_filename)(BdrvChild *child, BlockDriverState *new_base, 571 const char *filename, Error **errp); 572 }; 573 574 extern const BdrvChildRole child_file; 575 extern const BdrvChildRole child_format; 576 extern const BdrvChildRole child_backing; 577 578 struct BdrvChild { 579 BlockDriverState *bs; 580 char *name; 581 const BdrvChildRole *role; 582 void *opaque; 583 584 /** 585 * Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask) 586 */ 587 uint64_t perm; 588 589 /** 590 * Permissions that can still be granted to other users of @bs while this 591 * BdrvChild is still attached to it. (BLK_PERM_* bitmask) 592 */ 593 uint64_t shared_perm; 594 595 QLIST_ENTRY(BdrvChild) next; 596 QLIST_ENTRY(BdrvChild) next_parent; 597 }; 598 599 /* 600 * Note: the function bdrv_append() copies and swaps contents of 601 * BlockDriverStates, so if you add new fields to this struct, please 602 * inspect bdrv_append() to determine if the new fields need to be 603 * copied as well. 604 */ 605 struct BlockDriverState { 606 /* Protected by big QEMU lock or read-only after opening. No special 607 * locking needed during I/O... 608 */ 609 int open_flags; /* flags used to open the file, re-used for re-open */ 610 bool read_only; /* if true, the media is read only */ 611 bool encrypted; /* if true, the media is encrypted */ 612 bool sg; /* if true, the device is a /dev/sg* */ 613 bool probed; /* if true, format was probed rather than specified */ 614 bool force_share; /* if true, always allow all shared permissions */ 615 bool implicit; /* if true, this filter node was automatically inserted */ 616 617 BlockDriver *drv; /* NULL means no media */ 618 void *opaque; 619 620 AioContext *aio_context; /* event loop used for fd handlers, timers, etc */ 621 /* long-running tasks intended to always use the same AioContext as this 622 * BDS may register themselves in this list to be notified of changes 623 * regarding this BDS's context */ 624 QLIST_HEAD(, BdrvAioNotifier) aio_notifiers; 625 bool walking_aio_notifiers; /* to make removal during iteration safe */ 626 627 char filename[PATH_MAX]; 628 char backing_file[PATH_MAX]; /* if non zero, the image is a diff of 629 this file image */ 630 char backing_format[16]; /* if non-zero and backing_file exists */ 631 632 QDict *full_open_options; 633 char exact_filename[PATH_MAX]; 634 635 BdrvChild *backing; 636 BdrvChild *file; 637 638 /* I/O Limits */ 639 BlockLimits bl; 640 641 /* Flags honored during pwrite (so far: BDRV_REQ_FUA) */ 642 unsigned int supported_write_flags; 643 /* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA, 644 * BDRV_REQ_MAY_UNMAP) */ 645 unsigned int supported_zero_flags; 646 647 /* the following member gives a name to every node on the bs graph. */ 648 char node_name[32]; 649 /* element of the list of named nodes building the graph */ 650 QTAILQ_ENTRY(BlockDriverState) node_list; 651 /* element of the list of all BlockDriverStates (all_bdrv_states) */ 652 QTAILQ_ENTRY(BlockDriverState) bs_list; 653 /* element of the list of monitor-owned BDS */ 654 QTAILQ_ENTRY(BlockDriverState) monitor_list; 655 int refcnt; 656 657 /* operation blockers */ 658 QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; 659 660 /* long-running background operation */ 661 BlockJob *job; 662 663 /* The node that this node inherited default options from (and a reopen on 664 * which can affect this node by changing these defaults). This is always a 665 * parent node of this node. */ 666 BlockDriverState *inherits_from; 667 QLIST_HEAD(, BdrvChild) children; 668 QLIST_HEAD(, BdrvChild) parents; 669 670 QDict *options; 671 QDict *explicit_options; 672 BlockdevDetectZeroesOptions detect_zeroes; 673 674 /* The error object in use for blocking operations on backing_hd */ 675 Error *backing_blocker; 676 677 /* Protected by AioContext lock */ 678 679 /* If we are reading a disk image, give its size in sectors. 680 * Generally read-only; it is written to by load_snapshot and 681 * save_snaphost, but the block layer is quiescent during those. 682 */ 683 int64_t total_sectors; 684 685 /* Callback before write request is processed */ 686 NotifierWithReturnList before_write_notifiers; 687 688 /* threshold limit for writes, in bytes. "High water mark". */ 689 uint64_t write_threshold_offset; 690 NotifierWithReturn write_threshold_notifier; 691 692 /* Writing to the list requires the BQL _and_ the dirty_bitmap_mutex. 693 * Reading from the list can be done with either the BQL or the 694 * dirty_bitmap_mutex. Modifying a bitmap only requires 695 * dirty_bitmap_mutex. */ 696 QemuMutex dirty_bitmap_mutex; 697 QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps; 698 699 /* Offset after the highest byte written to */ 700 Stat64 wr_highest_offset; 701 702 /* If true, copy read backing sectors into image. Can be >1 if more 703 * than one client has requested copy-on-read. Accessed with atomic 704 * ops. 705 */ 706 int copy_on_read; 707 708 /* number of in-flight requests; overall and serialising. 709 * Accessed with atomic ops. 710 */ 711 unsigned int in_flight; 712 unsigned int serialising_in_flight; 713 714 /* Internal to BDRV_POLL_WHILE and bdrv_wakeup. Accessed with atomic 715 * ops. 716 */ 717 bool wakeup; 718 719 /* counter for nested bdrv_io_plug. 720 * Accessed with atomic ops. 721 */ 722 unsigned io_plugged; 723 724 /* do we need to tell the quest if we have a volatile write cache? */ 725 int enable_write_cache; 726 727 /* Accessed with atomic ops. */ 728 int quiesce_counter; 729 int recursive_quiesce_counter; 730 731 unsigned int write_gen; /* Current data generation */ 732 733 /* Protected by reqs_lock. */ 734 CoMutex reqs_lock; 735 QLIST_HEAD(, BdrvTrackedRequest) tracked_requests; 736 CoQueue flush_queue; /* Serializing flush queue */ 737 bool active_flush_req; /* Flush request in flight? */ 738 739 /* Only read/written by whoever has set active_flush_req to true. */ 740 unsigned int flushed_gen; /* Flushed write generation */ 741 }; 742 743 struct BlockBackendRootState { 744 int open_flags; 745 bool read_only; 746 BlockdevDetectZeroesOptions detect_zeroes; 747 }; 748 749 typedef enum BlockMirrorBackingMode { 750 /* Reuse the existing backing chain from the source for the target. 751 * - sync=full: Set backing BDS to NULL. 752 * - sync=top: Use source's backing BDS. 753 * - sync=none: Use source as the backing BDS. */ 754 MIRROR_SOURCE_BACKING_CHAIN, 755 756 /* Open the target's backing chain completely anew */ 757 MIRROR_OPEN_BACKING_CHAIN, 758 759 /* Do not change the target's backing BDS after job completion */ 760 MIRROR_LEAVE_BACKING_CHAIN, 761 } BlockMirrorBackingMode; 762 763 static inline BlockDriverState *backing_bs(BlockDriverState *bs) 764 { 765 return bs->backing ? bs->backing->bs : NULL; 766 } 767 768 769 /* Essential block drivers which must always be statically linked into qemu, and 770 * which therefore can be accessed without using bdrv_find_format() */ 771 extern BlockDriver bdrv_file; 772 extern BlockDriver bdrv_raw; 773 extern BlockDriver bdrv_qcow2; 774 775 int coroutine_fn bdrv_co_preadv(BdrvChild *child, 776 int64_t offset, unsigned int bytes, QEMUIOVector *qiov, 777 BdrvRequestFlags flags); 778 int coroutine_fn bdrv_co_pwritev(BdrvChild *child, 779 int64_t offset, unsigned int bytes, QEMUIOVector *qiov, 780 BdrvRequestFlags flags); 781 782 void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent); 783 void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent); 784 785 int get_tmp_filename(char *filename, int size); 786 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size, 787 const char *filename); 788 789 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, 790 QDict *options); 791 792 793 /** 794 * bdrv_add_before_write_notifier: 795 * 796 * Register a callback that is invoked before write requests are processed but 797 * after any throttling or waiting for overlapping requests. 798 */ 799 void bdrv_add_before_write_notifier(BlockDriverState *bs, 800 NotifierWithReturn *notifier); 801 802 /** 803 * bdrv_detach_aio_context: 804 * 805 * May be called from .bdrv_detach_aio_context() to detach children from the 806 * current #AioContext. This is only needed by block drivers that manage their 807 * own children. Both ->file and ->backing are automatically handled and 808 * block drivers should not call this function on them explicitly. 809 */ 810 void bdrv_detach_aio_context(BlockDriverState *bs); 811 812 /** 813 * bdrv_attach_aio_context: 814 * 815 * May be called from .bdrv_attach_aio_context() to attach children to the new 816 * #AioContext. This is only needed by block drivers that manage their own 817 * children. Both ->file and ->backing are automatically handled and block 818 * drivers should not call this function on them explicitly. 819 */ 820 void bdrv_attach_aio_context(BlockDriverState *bs, 821 AioContext *new_context); 822 823 /** 824 * bdrv_add_aio_context_notifier: 825 * 826 * If a long-running job intends to be always run in the same AioContext as a 827 * certain BDS, it may use this function to be notified of changes regarding the 828 * association of the BDS to an AioContext. 829 * 830 * attached_aio_context() is called after the target BDS has been attached to a 831 * new AioContext; detach_aio_context() is called before the target BDS is being 832 * detached from its old AioContext. 833 */ 834 void bdrv_add_aio_context_notifier(BlockDriverState *bs, 835 void (*attached_aio_context)(AioContext *new_context, void *opaque), 836 void (*detach_aio_context)(void *opaque), void *opaque); 837 838 /** 839 * bdrv_remove_aio_context_notifier: 840 * 841 * Unsubscribe of change notifications regarding the BDS's AioContext. The 842 * parameters given here have to be the same as those given to 843 * bdrv_add_aio_context_notifier(). 844 */ 845 void bdrv_remove_aio_context_notifier(BlockDriverState *bs, 846 void (*aio_context_attached)(AioContext *, 847 void *), 848 void (*aio_context_detached)(void *), 849 void *opaque); 850 851 /** 852 * bdrv_wakeup: 853 * @bs: The BlockDriverState for which an I/O operation has been completed. 854 * 855 * Wake up the main thread if it is waiting on BDRV_POLL_WHILE. During 856 * synchronous I/O on a BlockDriverState that is attached to another 857 * I/O thread, the main thread lets the I/O thread's event loop run, 858 * waiting for the I/O operation to complete. A bdrv_wakeup will wake 859 * up the main thread if necessary. 860 * 861 * Manual calls to bdrv_wakeup are rarely necessary, because 862 * bdrv_dec_in_flight already calls it. 863 */ 864 void bdrv_wakeup(BlockDriverState *bs); 865 866 #ifdef _WIN32 867 int is_windows_drive(const char *filename); 868 #endif 869 870 /** 871 * stream_start: 872 * @job_id: The id of the newly-created job, or %NULL to use the 873 * device name of @bs. 874 * @bs: Block device to operate on. 875 * @base: Block device that will become the new base, or %NULL to 876 * flatten the whole backing file chain onto @bs. 877 * @backing_file_str: The file name that will be written to @bs as the 878 * the new backing file if the job completes. Ignored if @base is %NULL. 879 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 880 * @on_error: The action to take upon error. 881 * @errp: Error object. 882 * 883 * Start a streaming operation on @bs. Clusters that are unallocated 884 * in @bs, but allocated in any image between @base and @bs (both 885 * exclusive) will be written to @bs. At the end of a successful 886 * streaming job, the backing file of @bs will be changed to 887 * @backing_file_str in the written image and to @base in the live 888 * BlockDriverState. 889 */ 890 void stream_start(const char *job_id, BlockDriverState *bs, 891 BlockDriverState *base, const char *backing_file_str, 892 int64_t speed, BlockdevOnError on_error, Error **errp); 893 894 /** 895 * commit_start: 896 * @job_id: The id of the newly-created job, or %NULL to use the 897 * device name of @bs. 898 * @bs: Active block device. 899 * @top: Top block device to be committed. 900 * @base: Block device that will be written into, and become the new top. 901 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 902 * @on_error: The action to take upon error. 903 * @backing_file_str: String to use as the backing file in @top's overlay 904 * @filter_node_name: The node name that should be assigned to the filter 905 * driver that the commit job inserts into the graph above @top. NULL means 906 * that a node name should be autogenerated. 907 * @errp: Error object. 908 * 909 */ 910 void commit_start(const char *job_id, BlockDriverState *bs, 911 BlockDriverState *base, BlockDriverState *top, int64_t speed, 912 BlockdevOnError on_error, const char *backing_file_str, 913 const char *filter_node_name, Error **errp); 914 /** 915 * commit_active_start: 916 * @job_id: The id of the newly-created job, or %NULL to use the 917 * device name of @bs. 918 * @bs: Active block device to be committed. 919 * @base: Block device that will be written into, and become the new top. 920 * @creation_flags: Flags that control the behavior of the Job lifetime. 921 * See @BlockJobCreateFlags 922 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 923 * @on_error: The action to take upon error. 924 * @filter_node_name: The node name that should be assigned to the filter 925 * driver that the commit job inserts into the graph above @bs. NULL means that 926 * a node name should be autogenerated. 927 * @cb: Completion function for the job. 928 * @opaque: Opaque pointer value passed to @cb. 929 * @auto_complete: Auto complete the job. 930 * @errp: Error object. 931 * 932 */ 933 void commit_active_start(const char *job_id, BlockDriverState *bs, 934 BlockDriverState *base, int creation_flags, 935 int64_t speed, BlockdevOnError on_error, 936 const char *filter_node_name, 937 BlockCompletionFunc *cb, void *opaque, 938 bool auto_complete, Error **errp); 939 /* 940 * mirror_start: 941 * @job_id: The id of the newly-created job, or %NULL to use the 942 * device name of @bs. 943 * @bs: Block device to operate on. 944 * @target: Block device to write to. 945 * @replaces: Block graph node name to replace once the mirror is done. Can 946 * only be used when full mirroring is selected. 947 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 948 * @granularity: The chosen granularity for the dirty bitmap. 949 * @buf_size: The amount of data that can be in flight at one time. 950 * @mode: Whether to collapse all images in the chain to the target. 951 * @backing_mode: How to establish the target's backing chain after completion. 952 * @on_source_error: The action to take upon error reading from the source. 953 * @on_target_error: The action to take upon error writing to the target. 954 * @unmap: Whether to unmap target where source sectors only contain zeroes. 955 * @filter_node_name: The node name that should be assigned to the filter 956 * driver that the mirror job inserts into the graph above @bs. NULL means that 957 * a node name should be autogenerated. 958 * @errp: Error object. 959 * 960 * Start a mirroring operation on @bs. Clusters that are allocated 961 * in @bs will be written to @target until the job is cancelled or 962 * manually completed. At the end of a successful mirroring job, 963 * @bs will be switched to read from @target. 964 */ 965 void mirror_start(const char *job_id, BlockDriverState *bs, 966 BlockDriverState *target, const char *replaces, 967 int64_t speed, uint32_t granularity, int64_t buf_size, 968 MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, 969 BlockdevOnError on_source_error, 970 BlockdevOnError on_target_error, 971 bool unmap, const char *filter_node_name, Error **errp); 972 973 /* 974 * backup_job_create: 975 * @job_id: The id of the newly-created job, or %NULL to use the 976 * device name of @bs. 977 * @bs: Block device to operate on. 978 * @target: Block device to write to. 979 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 980 * @sync_mode: What parts of the disk image should be copied to the destination. 981 * @sync_bitmap: The dirty bitmap if sync_mode is MIRROR_SYNC_MODE_INCREMENTAL. 982 * @on_source_error: The action to take upon error reading from the source. 983 * @on_target_error: The action to take upon error writing to the target. 984 * @creation_flags: Flags that control the behavior of the Job lifetime. 985 * See @BlockJobCreateFlags 986 * @cb: Completion function for the job. 987 * @opaque: Opaque pointer value passed to @cb. 988 * @txn: Transaction that this job is part of (may be NULL). 989 * 990 * Create a backup operation on @bs. Clusters in @bs are written to @target 991 * until the job is cancelled or manually completed. 992 */ 993 BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, 994 BlockDriverState *target, int64_t speed, 995 MirrorSyncMode sync_mode, 996 BdrvDirtyBitmap *sync_bitmap, 997 bool compress, 998 BlockdevOnError on_source_error, 999 BlockdevOnError on_target_error, 1000 int creation_flags, 1001 BlockCompletionFunc *cb, void *opaque, 1002 BlockJobTxn *txn, Error **errp); 1003 1004 void hmp_drive_add_node(Monitor *mon, const char *optstr); 1005 1006 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, 1007 const char *child_name, 1008 const BdrvChildRole *child_role, 1009 uint64_t perm, uint64_t shared_perm, 1010 void *opaque, Error **errp); 1011 void bdrv_root_unref_child(BdrvChild *child); 1012 1013 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, 1014 Error **errp); 1015 1016 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by 1017 * block filters: Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED and RESIZE to 1018 * all children */ 1019 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c, 1020 const BdrvChildRole *role, 1021 BlockReopenQueue *reopen_queue, 1022 uint64_t perm, uint64_t shared, 1023 uint64_t *nperm, uint64_t *nshared); 1024 1025 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by 1026 * (non-raw) image formats: Like above for bs->backing, but for bs->file it 1027 * requires WRITE | RESIZE for read-write images, always requires 1028 * CONSISTENT_READ and doesn't share WRITE. */ 1029 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c, 1030 const BdrvChildRole *role, 1031 BlockReopenQueue *reopen_queue, 1032 uint64_t perm, uint64_t shared, 1033 uint64_t *nperm, uint64_t *nshared); 1034 1035 /* 1036 * Default implementation for drivers to pass bdrv_co_get_block_status() to 1037 * their file. 1038 */ 1039 int64_t coroutine_fn bdrv_co_get_block_status_from_file(BlockDriverState *bs, 1040 int64_t sector_num, 1041 int nb_sectors, 1042 int *pnum, 1043 BlockDriverState **file); 1044 /* 1045 * Default implementation for drivers to pass bdrv_co_get_block_status() to 1046 * their backing file. 1047 */ 1048 int64_t coroutine_fn bdrv_co_get_block_status_from_backing(BlockDriverState *bs, 1049 int64_t sector_num, 1050 int nb_sectors, 1051 int *pnum, 1052 BlockDriverState **file); 1053 const char *bdrv_get_parent_name(const BlockDriverState *bs); 1054 void blk_dev_change_media_cb(BlockBackend *blk, bool load, Error **errp); 1055 bool blk_dev_has_removable_media(BlockBackend *blk); 1056 bool blk_dev_has_tray(BlockBackend *blk); 1057 void blk_dev_eject_request(BlockBackend *blk, bool force); 1058 bool blk_dev_is_tray_open(BlockBackend *blk); 1059 bool blk_dev_is_medium_locked(BlockBackend *blk); 1060 1061 void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes); 1062 1063 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out); 1064 void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in); 1065 1066 void bdrv_inc_in_flight(BlockDriverState *bs); 1067 void bdrv_dec_in_flight(BlockDriverState *bs); 1068 1069 void blockdev_close_all_bdrv_states(void); 1070 1071 #endif /* BLOCK_INT_H */ 1072