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 "block/aio-wait.h" 30 #include "qemu/queue.h" 31 #include "qemu/coroutine.h" 32 #include "qemu/stats64.h" 33 #include "qemu/timer.h" 34 #include "qemu/hbitmap.h" 35 #include "block/snapshot.h" 36 #include "qemu/main-loop.h" 37 #include "qemu/throttle.h" 38 39 #define BLOCK_FLAG_LAZY_REFCOUNTS 8 40 41 #define BLOCK_OPT_SIZE "size" 42 #define BLOCK_OPT_ENCRYPT "encryption" 43 #define BLOCK_OPT_ENCRYPT_FORMAT "encrypt.format" 44 #define BLOCK_OPT_COMPAT6 "compat6" 45 #define BLOCK_OPT_HWVERSION "hwversion" 46 #define BLOCK_OPT_BACKING_FILE "backing_file" 47 #define BLOCK_OPT_BACKING_FMT "backing_fmt" 48 #define BLOCK_OPT_CLUSTER_SIZE "cluster_size" 49 #define BLOCK_OPT_TABLE_SIZE "table_size" 50 #define BLOCK_OPT_PREALLOC "preallocation" 51 #define BLOCK_OPT_SUBFMT "subformat" 52 #define BLOCK_OPT_COMPAT_LEVEL "compat" 53 #define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts" 54 #define BLOCK_OPT_ADAPTER_TYPE "adapter_type" 55 #define BLOCK_OPT_REDUNDANCY "redundancy" 56 #define BLOCK_OPT_NOCOW "nocow" 57 #define BLOCK_OPT_OBJECT_SIZE "object_size" 58 #define BLOCK_OPT_REFCOUNT_BITS "refcount_bits" 59 60 #define BLOCK_PROBE_BUF_SIZE 512 61 62 enum BdrvTrackedRequestType { 63 BDRV_TRACKED_READ, 64 BDRV_TRACKED_WRITE, 65 BDRV_TRACKED_DISCARD, 66 }; 67 68 typedef struct BdrvTrackedRequest { 69 BlockDriverState *bs; 70 int64_t offset; 71 unsigned int bytes; 72 enum BdrvTrackedRequestType type; 73 74 bool serialising; 75 int64_t overlap_offset; 76 unsigned int overlap_bytes; 77 78 QLIST_ENTRY(BdrvTrackedRequest) list; 79 Coroutine *co; /* owner, used for deadlock detection */ 80 CoQueue wait_queue; /* coroutines blocked on this request */ 81 82 struct BdrvTrackedRequest *waiting_for; 83 } BdrvTrackedRequest; 84 85 struct BlockDriver { 86 const char *format_name; 87 int instance_size; 88 89 /* set to true if the BlockDriver is a block filter. Block filters pass 90 * certain callbacks that refer to data (see block.c) to their bs->file if 91 * the driver doesn't implement them. Drivers that do not wish to forward 92 * must implement them and return -ENOTSUP. 93 */ 94 bool is_filter; 95 /* for snapshots block filter like Quorum can implement the 96 * following recursive callback. 97 * It's purpose is to recurse on the filter children while calling 98 * bdrv_recurse_is_first_non_filter on them. 99 * For a sample implementation look in the future Quorum block filter. 100 */ 101 bool (*bdrv_recurse_is_first_non_filter)(BlockDriverState *bs, 102 BlockDriverState *candidate); 103 104 int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename); 105 int (*bdrv_probe_device)(const char *filename); 106 107 /* Any driver implementing this callback is expected to be able to handle 108 * NULL file names in its .bdrv_open() implementation */ 109 void (*bdrv_parse_filename)(const char *filename, QDict *options, Error **errp); 110 /* Drivers not implementing bdrv_parse_filename nor bdrv_open should have 111 * this field set to true, except ones that are defined only by their 112 * child's bs. 113 * An example of the last type will be the quorum block driver. 114 */ 115 bool bdrv_needs_filename; 116 117 /* Set if a driver can support backing files */ 118 bool supports_backing; 119 120 /* For handling image reopen for split or non-split files */ 121 int (*bdrv_reopen_prepare)(BDRVReopenState *reopen_state, 122 BlockReopenQueue *queue, Error **errp); 123 void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state); 124 void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state); 125 void (*bdrv_join_options)(QDict *options, QDict *old_options); 126 127 int (*bdrv_open)(BlockDriverState *bs, QDict *options, int flags, 128 Error **errp); 129 130 /* Protocol drivers should implement this instead of bdrv_open */ 131 int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags, 132 Error **errp); 133 void (*bdrv_close)(BlockDriverState *bs); 134 int coroutine_fn (*bdrv_co_create)(BlockdevCreateOptions *opts, 135 Error **errp); 136 int coroutine_fn (*bdrv_co_create_opts)(const char *filename, 137 QemuOpts *opts, 138 Error **errp); 139 int (*bdrv_make_empty)(BlockDriverState *bs); 140 141 void (*bdrv_refresh_filename)(BlockDriverState *bs, QDict *options); 142 143 /* aio */ 144 BlockAIOCB *(*bdrv_aio_readv)(BlockDriverState *bs, 145 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 146 BlockCompletionFunc *cb, void *opaque); 147 BlockAIOCB *(*bdrv_aio_writev)(BlockDriverState *bs, 148 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 149 BlockCompletionFunc *cb, void *opaque); 150 BlockAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs, 151 BlockCompletionFunc *cb, void *opaque); 152 BlockAIOCB *(*bdrv_aio_pdiscard)(BlockDriverState *bs, 153 int64_t offset, int bytes, 154 BlockCompletionFunc *cb, void *opaque); 155 156 int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs, 157 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); 158 159 /** 160 * @offset: position in bytes to read at 161 * @bytes: number of bytes to read 162 * @qiov: the buffers to fill with read data 163 * @flags: currently unused, always 0 164 * 165 * @offset and @bytes will be a multiple of 'request_alignment', 166 * but the length of individual @qiov elements does not have to 167 * be a multiple. 168 * 169 * @bytes will always equal the total size of @qiov, and will be 170 * no larger than 'max_transfer'. 171 * 172 * The buffer in @qiov may point directly to guest memory. 173 */ 174 int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs, 175 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags); 176 int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs, 177 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); 178 int coroutine_fn (*bdrv_co_writev_flags)(BlockDriverState *bs, 179 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int flags); 180 /** 181 * @offset: position in bytes to write at 182 * @bytes: number of bytes to write 183 * @qiov: the buffers containing data to write 184 * @flags: zero or more bits allowed by 'supported_write_flags' 185 * 186 * @offset and @bytes will be a multiple of 'request_alignment', 187 * but the length of individual @qiov elements does not have to 188 * be a multiple. 189 * 190 * @bytes will always equal the total size of @qiov, and will be 191 * no larger than 'max_transfer'. 192 * 193 * The buffer in @qiov may point directly to guest memory. 194 */ 195 int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs, 196 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags); 197 198 /* 199 * Efficiently zero a region of the disk image. Typically an image format 200 * would use a compact metadata representation to implement this. This 201 * function pointer may be NULL or return -ENOSUP and .bdrv_co_writev() 202 * will be called instead. 203 */ 204 int coroutine_fn (*bdrv_co_pwrite_zeroes)(BlockDriverState *bs, 205 int64_t offset, int bytes, BdrvRequestFlags flags); 206 int coroutine_fn (*bdrv_co_pdiscard)(BlockDriverState *bs, 207 int64_t offset, int bytes); 208 209 /* 210 * Building block for bdrv_block_status[_above] and 211 * bdrv_is_allocated[_above]. The driver should answer only 212 * according to the current layer, and should only need to set 213 * BDRV_BLOCK_DATA, BDRV_BLOCK_ZERO, BDRV_BLOCK_OFFSET_VALID, 214 * and/or BDRV_BLOCK_RAW; if the current layer defers to a backing 215 * layer, the result should be 0 (and not BDRV_BLOCK_ZERO). See 216 * block.h for the overall meaning of the bits. As a hint, the 217 * flag want_zero is true if the caller cares more about precise 218 * mappings (favor accurate _OFFSET_VALID/_ZERO) or false for 219 * overall allocation (favor larger *pnum, perhaps by reporting 220 * _DATA instead of _ZERO). The block layer guarantees input 221 * clamped to bdrv_getlength() and aligned to request_alignment, 222 * as well as non-NULL pnum, map, and file; in turn, the driver 223 * must return an error or set pnum to an aligned non-zero value. 224 */ 225 int coroutine_fn (*bdrv_co_block_status)(BlockDriverState *bs, 226 bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum, 227 int64_t *map, BlockDriverState **file); 228 229 /* 230 * Invalidate any cached meta-data. 231 */ 232 void coroutine_fn (*bdrv_co_invalidate_cache)(BlockDriverState *bs, 233 Error **errp); 234 int (*bdrv_inactivate)(BlockDriverState *bs); 235 236 /* 237 * Flushes all data for all layers by calling bdrv_co_flush for underlying 238 * layers, if needed. This function is needed for deterministic 239 * synchronization of the flush finishing callback. 240 */ 241 int coroutine_fn (*bdrv_co_flush)(BlockDriverState *bs); 242 243 /* 244 * Flushes all data that was already written to the OS all the way down to 245 * the disk (for example file-posix.c calls fsync()). 246 */ 247 int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs); 248 249 /* 250 * Flushes all internal caches to the OS. The data may still sit in a 251 * writeback cache of the host OS, but it will survive a crash of the qemu 252 * process. 253 */ 254 int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs); 255 256 /* 257 * Drivers setting this field must be able to work with just a plain 258 * filename with '<protocol_name>:' as a prefix, and no other options. 259 * Options may be extracted from the filename by implementing 260 * bdrv_parse_filename. 261 */ 262 const char *protocol_name; 263 int (*bdrv_truncate)(BlockDriverState *bs, int64_t offset, 264 PreallocMode prealloc, Error **errp); 265 266 int64_t (*bdrv_getlength)(BlockDriverState *bs); 267 bool has_variable_length; 268 int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs); 269 BlockMeasureInfo *(*bdrv_measure)(QemuOpts *opts, BlockDriverState *in_bs, 270 Error **errp); 271 272 int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs, 273 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov); 274 275 int (*bdrv_snapshot_create)(BlockDriverState *bs, 276 QEMUSnapshotInfo *sn_info); 277 int (*bdrv_snapshot_goto)(BlockDriverState *bs, 278 const char *snapshot_id); 279 int (*bdrv_snapshot_delete)(BlockDriverState *bs, 280 const char *snapshot_id, 281 const char *name, 282 Error **errp); 283 int (*bdrv_snapshot_list)(BlockDriverState *bs, 284 QEMUSnapshotInfo **psn_info); 285 int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs, 286 const char *snapshot_id, 287 const char *name, 288 Error **errp); 289 int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi); 290 ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs); 291 292 int coroutine_fn (*bdrv_save_vmstate)(BlockDriverState *bs, 293 QEMUIOVector *qiov, 294 int64_t pos); 295 int coroutine_fn (*bdrv_load_vmstate)(BlockDriverState *bs, 296 QEMUIOVector *qiov, 297 int64_t pos); 298 299 int (*bdrv_change_backing_file)(BlockDriverState *bs, 300 const char *backing_file, const char *backing_fmt); 301 302 /* removable device specific */ 303 bool (*bdrv_is_inserted)(BlockDriverState *bs); 304 void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag); 305 void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked); 306 307 /* to control generic scsi devices */ 308 BlockAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs, 309 unsigned long int req, void *buf, 310 BlockCompletionFunc *cb, void *opaque); 311 int coroutine_fn (*bdrv_co_ioctl)(BlockDriverState *bs, 312 unsigned long int req, void *buf); 313 314 /* List of options for creating images, terminated by name == NULL */ 315 QemuOptsList *create_opts; 316 317 /* 318 * Returns 0 for completed check, -errno for internal errors. 319 * The check results are stored in result. 320 */ 321 int coroutine_fn (*bdrv_co_check)(BlockDriverState *bs, 322 BdrvCheckResult *result, 323 BdrvCheckMode fix); 324 325 int (*bdrv_amend_options)(BlockDriverState *bs, QemuOpts *opts, 326 BlockDriverAmendStatusCB *status_cb, 327 void *cb_opaque); 328 329 void (*bdrv_debug_event)(BlockDriverState *bs, BlkdebugEvent event); 330 331 /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */ 332 int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event, 333 const char *tag); 334 int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs, 335 const char *tag); 336 int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag); 337 bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag); 338 339 void (*bdrv_refresh_limits)(BlockDriverState *bs, Error **errp); 340 341 /* 342 * Returns 1 if newly created images are guaranteed to contain only 343 * zeros, 0 otherwise. 344 */ 345 int (*bdrv_has_zero_init)(BlockDriverState *bs); 346 347 /* Remove fd handlers, timers, and other event loop callbacks so the event 348 * loop is no longer in use. Called with no in-flight requests and in 349 * depth-first traversal order with parents before child nodes. 350 */ 351 void (*bdrv_detach_aio_context)(BlockDriverState *bs); 352 353 /* Add fd handlers, timers, and other event loop callbacks so I/O requests 354 * can be processed again. Called with no in-flight requests and in 355 * depth-first traversal order with child nodes before parent nodes. 356 */ 357 void (*bdrv_attach_aio_context)(BlockDriverState *bs, 358 AioContext *new_context); 359 360 /* io queue for linux-aio */ 361 void (*bdrv_io_plug)(BlockDriverState *bs); 362 void (*bdrv_io_unplug)(BlockDriverState *bs); 363 364 /** 365 * Try to get @bs's logical and physical block size. 366 * On success, store them in @bsz and return zero. 367 * On failure, return negative errno. 368 */ 369 int (*bdrv_probe_blocksizes)(BlockDriverState *bs, BlockSizes *bsz); 370 /** 371 * Try to get @bs's geometry (cyls, heads, sectors) 372 * On success, store them in @geo and return 0. 373 * On failure return -errno. 374 * Only drivers that want to override guest geometry implement this 375 * callback; see hd_geometry_guess(). 376 */ 377 int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo); 378 379 /** 380 * bdrv_co_drain_begin is called if implemented in the beginning of a 381 * drain operation to drain and stop any internal sources of requests in 382 * the driver. 383 * bdrv_co_drain_end is called if implemented at the end of the drain. 384 * 385 * They should be used by the driver to e.g. manage scheduled I/O 386 * requests, or toggle an internal state. After the end of the drain new 387 * requests will continue normally. 388 */ 389 void coroutine_fn (*bdrv_co_drain_begin)(BlockDriverState *bs); 390 void coroutine_fn (*bdrv_co_drain_end)(BlockDriverState *bs); 391 392 void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child, 393 Error **errp); 394 void (*bdrv_del_child)(BlockDriverState *parent, BdrvChild *child, 395 Error **errp); 396 397 /** 398 * Informs the block driver that a permission change is intended. The 399 * driver checks whether the change is permissible and may take other 400 * preparations for the change (e.g. get file system locks). This operation 401 * is always followed either by a call to either .bdrv_set_perm or 402 * .bdrv_abort_perm_update. 403 * 404 * Checks whether the requested set of cumulative permissions in @perm 405 * can be granted for accessing @bs and whether no other users are using 406 * permissions other than those given in @shared (both arguments take 407 * BLK_PERM_* bitmasks). 408 * 409 * If both conditions are met, 0 is returned. Otherwise, -errno is returned 410 * and errp is set to an error describing the conflict. 411 */ 412 int (*bdrv_check_perm)(BlockDriverState *bs, uint64_t perm, 413 uint64_t shared, Error **errp); 414 415 /** 416 * Called to inform the driver that the set of cumulative set of used 417 * permissions for @bs has changed to @perm, and the set of sharable 418 * permission to @shared. The driver can use this to propagate changes to 419 * its children (i.e. request permissions only if a parent actually needs 420 * them). 421 * 422 * This function is only invoked after bdrv_check_perm(), so block drivers 423 * may rely on preparations made in their .bdrv_check_perm implementation. 424 */ 425 void (*bdrv_set_perm)(BlockDriverState *bs, uint64_t perm, uint64_t shared); 426 427 /* 428 * Called to inform the driver that after a previous bdrv_check_perm() 429 * call, the permission update is not performed and any preparations made 430 * for it (e.g. taken file locks) need to be undone. 431 * 432 * This function can be called even for nodes that never saw a 433 * bdrv_check_perm() call. It is a no-op then. 434 */ 435 void (*bdrv_abort_perm_update)(BlockDriverState *bs); 436 437 /** 438 * Returns in @nperm and @nshared the permissions that the driver for @bs 439 * needs on its child @c, based on the cumulative permissions requested by 440 * the parents in @parent_perm and @parent_shared. 441 * 442 * If @c is NULL, return the permissions for attaching a new child for the 443 * given @role. 444 * 445 * If @reopen_queue is non-NULL, don't return the currently needed 446 * permissions, but those that will be needed after applying the 447 * @reopen_queue. 448 */ 449 void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c, 450 const BdrvChildRole *role, 451 BlockReopenQueue *reopen_queue, 452 uint64_t parent_perm, uint64_t parent_shared, 453 uint64_t *nperm, uint64_t *nshared); 454 455 /** 456 * Bitmaps should be marked as 'IN_USE' in the image on reopening image 457 * as rw. This handler should realize it. It also should unset readonly 458 * field of BlockDirtyBitmap's in case of success. 459 */ 460 int (*bdrv_reopen_bitmaps_rw)(BlockDriverState *bs, Error **errp); 461 bool (*bdrv_can_store_new_dirty_bitmap)(BlockDriverState *bs, 462 const char *name, 463 uint32_t granularity, 464 Error **errp); 465 void (*bdrv_remove_persistent_dirty_bitmap)(BlockDriverState *bs, 466 const char *name, 467 Error **errp); 468 469 /** 470 * Register/unregister a buffer for I/O. For example, when the driver is 471 * interested to know the memory areas that will later be used in iovs, so 472 * that it can do IOMMU mapping with VFIO etc., in order to get better 473 * performance. In the case of VFIO drivers, this callback is used to do 474 * DMA mapping for hot buffers. 475 */ 476 void (*bdrv_register_buf)(BlockDriverState *bs, void *host, size_t size); 477 void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host); 478 QLIST_ENTRY(BlockDriver) list; 479 }; 480 481 typedef struct BlockLimits { 482 /* Alignment requirement, in bytes, for offset/length of I/O 483 * requests. Must be a power of 2 less than INT_MAX; defaults to 484 * 1 for drivers with modern byte interfaces, and to 512 485 * otherwise. */ 486 uint32_t request_alignment; 487 488 /* Maximum number of bytes that can be discarded at once (since it 489 * is signed, it must be < 2G, if set). Must be multiple of 490 * pdiscard_alignment, but need not be power of 2. May be 0 if no 491 * inherent 32-bit limit */ 492 int32_t max_pdiscard; 493 494 /* Optimal alignment for discard requests in bytes. A power of 2 495 * is best but not mandatory. Must be a multiple of 496 * bl.request_alignment, and must be less than max_pdiscard if 497 * that is set. May be 0 if bl.request_alignment is good enough */ 498 uint32_t pdiscard_alignment; 499 500 /* Maximum number of bytes that can zeroized at once (since it is 501 * signed, it must be < 2G, if set). Must be multiple of 502 * pwrite_zeroes_alignment. May be 0 if no inherent 32-bit limit */ 503 int32_t max_pwrite_zeroes; 504 505 /* Optimal alignment for write zeroes requests in bytes. A power 506 * of 2 is best but not mandatory. Must be a multiple of 507 * bl.request_alignment, and must be less than max_pwrite_zeroes 508 * if that is set. May be 0 if bl.request_alignment is good 509 * enough */ 510 uint32_t pwrite_zeroes_alignment; 511 512 /* Optimal transfer length in bytes. A power of 2 is best but not 513 * mandatory. Must be a multiple of bl.request_alignment, or 0 if 514 * no preferred size */ 515 uint32_t opt_transfer; 516 517 /* Maximal transfer length in bytes. Need not be power of 2, but 518 * must be multiple of opt_transfer and bl.request_alignment, or 0 519 * for no 32-bit limit. For now, anything larger than INT_MAX is 520 * clamped down. */ 521 uint32_t max_transfer; 522 523 /* memory alignment, in bytes so that no bounce buffer is needed */ 524 size_t min_mem_alignment; 525 526 /* memory alignment, in bytes, for bounce buffer */ 527 size_t opt_mem_alignment; 528 529 /* maximum number of iovec elements */ 530 int max_iov; 531 } BlockLimits; 532 533 typedef struct BdrvOpBlocker BdrvOpBlocker; 534 535 typedef struct BdrvAioNotifier { 536 void (*attached_aio_context)(AioContext *new_context, void *opaque); 537 void (*detach_aio_context)(void *opaque); 538 539 void *opaque; 540 bool deleted; 541 542 QLIST_ENTRY(BdrvAioNotifier) list; 543 } BdrvAioNotifier; 544 545 struct BdrvChildRole { 546 /* If true, bdrv_replace_node() doesn't change the node this BdrvChild 547 * points to. */ 548 bool stay_at_node; 549 550 void (*inherit_options)(int *child_flags, QDict *child_options, 551 int parent_flags, QDict *parent_options); 552 553 void (*change_media)(BdrvChild *child, bool load); 554 void (*resize)(BdrvChild *child); 555 556 /* Returns a name that is supposedly more useful for human users than the 557 * node name for identifying the node in question (in particular, a BB 558 * name), or NULL if the parent can't provide a better name. */ 559 const char *(*get_name)(BdrvChild *child); 560 561 /* Returns a malloced string that describes the parent of the child for a 562 * human reader. This could be a node-name, BlockBackend name, qdev ID or 563 * QOM path of the device owning the BlockBackend, job type and ID etc. The 564 * caller is responsible for freeing the memory. */ 565 char *(*get_parent_desc)(BdrvChild *child); 566 567 /* 568 * If this pair of functions is implemented, the parent doesn't issue new 569 * requests after returning from .drained_begin() until .drained_end() is 570 * called. 571 * 572 * Note that this can be nested. If drained_begin() was called twice, new 573 * I/O is allowed only after drained_end() was called twice, too. 574 */ 575 void (*drained_begin)(BdrvChild *child); 576 void (*drained_end)(BdrvChild *child); 577 578 /* Notifies the parent that the child has been activated/inactivated (e.g. 579 * when migration is completing) and it can start/stop requesting 580 * permissions and doing I/O on it. */ 581 void (*activate)(BdrvChild *child, Error **errp); 582 int (*inactivate)(BdrvChild *child); 583 584 void (*attach)(BdrvChild *child); 585 void (*detach)(BdrvChild *child); 586 587 /* Notifies the parent that the filename of its child has changed (e.g. 588 * because the direct child was removed from the backing chain), so that it 589 * can update its reference. */ 590 int (*update_filename)(BdrvChild *child, BlockDriverState *new_base, 591 const char *filename, Error **errp); 592 }; 593 594 extern const BdrvChildRole child_file; 595 extern const BdrvChildRole child_format; 596 extern const BdrvChildRole child_backing; 597 598 struct BdrvChild { 599 BlockDriverState *bs; 600 char *name; 601 const BdrvChildRole *role; 602 void *opaque; 603 604 /** 605 * Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask) 606 */ 607 uint64_t perm; 608 609 /** 610 * Permissions that can still be granted to other users of @bs while this 611 * BdrvChild is still attached to it. (BLK_PERM_* bitmask) 612 */ 613 uint64_t shared_perm; 614 615 QLIST_ENTRY(BdrvChild) next; 616 QLIST_ENTRY(BdrvChild) next_parent; 617 }; 618 619 /* 620 * Note: the function bdrv_append() copies and swaps contents of 621 * BlockDriverStates, so if you add new fields to this struct, please 622 * inspect bdrv_append() to determine if the new fields need to be 623 * copied as well. 624 */ 625 struct BlockDriverState { 626 /* Protected by big QEMU lock or read-only after opening. No special 627 * locking needed during I/O... 628 */ 629 int open_flags; /* flags used to open the file, re-used for re-open */ 630 bool read_only; /* if true, the media is read only */ 631 bool encrypted; /* if true, the media is encrypted */ 632 bool sg; /* if true, the device is a /dev/sg* */ 633 bool probed; /* if true, format was probed rather than specified */ 634 bool force_share; /* if true, always allow all shared permissions */ 635 bool implicit; /* if true, this filter node was automatically inserted */ 636 637 BlockDriver *drv; /* NULL means no media */ 638 void *opaque; 639 640 AioContext *aio_context; /* event loop used for fd handlers, timers, etc */ 641 /* long-running tasks intended to always use the same AioContext as this 642 * BDS may register themselves in this list to be notified of changes 643 * regarding this BDS's context */ 644 QLIST_HEAD(, BdrvAioNotifier) aio_notifiers; 645 bool walking_aio_notifiers; /* to make removal during iteration safe */ 646 647 char filename[PATH_MAX]; 648 char backing_file[PATH_MAX]; /* if non zero, the image is a diff of 649 this file image */ 650 char backing_format[16]; /* if non-zero and backing_file exists */ 651 652 QDict *full_open_options; 653 char exact_filename[PATH_MAX]; 654 655 BdrvChild *backing; 656 BdrvChild *file; 657 658 /* I/O Limits */ 659 BlockLimits bl; 660 661 /* Flags honored during pwrite (so far: BDRV_REQ_FUA) */ 662 unsigned int supported_write_flags; 663 /* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA, 664 * BDRV_REQ_MAY_UNMAP) */ 665 unsigned int supported_zero_flags; 666 667 /* the following member gives a name to every node on the bs graph. */ 668 char node_name[32]; 669 /* element of the list of named nodes building the graph */ 670 QTAILQ_ENTRY(BlockDriverState) node_list; 671 /* element of the list of all BlockDriverStates (all_bdrv_states) */ 672 QTAILQ_ENTRY(BlockDriverState) bs_list; 673 /* element of the list of monitor-owned BDS */ 674 QTAILQ_ENTRY(BlockDriverState) monitor_list; 675 int refcnt; 676 677 /* operation blockers */ 678 QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; 679 680 /* long-running background operation */ 681 BlockJob *job; 682 683 /* The node that this node inherited default options from (and a reopen on 684 * which can affect this node by changing these defaults). This is always a 685 * parent node of this node. */ 686 BlockDriverState *inherits_from; 687 QLIST_HEAD(, BdrvChild) children; 688 QLIST_HEAD(, BdrvChild) parents; 689 690 QDict *options; 691 QDict *explicit_options; 692 BlockdevDetectZeroesOptions detect_zeroes; 693 694 /* The error object in use for blocking operations on backing_hd */ 695 Error *backing_blocker; 696 697 /* Protected by AioContext lock */ 698 699 /* If we are reading a disk image, give its size in sectors. 700 * Generally read-only; it is written to by load_snapshot and 701 * save_snaphost, but the block layer is quiescent during those. 702 */ 703 int64_t total_sectors; 704 705 /* Callback before write request is processed */ 706 NotifierWithReturnList before_write_notifiers; 707 708 /* threshold limit for writes, in bytes. "High water mark". */ 709 uint64_t write_threshold_offset; 710 NotifierWithReturn write_threshold_notifier; 711 712 /* Writing to the list requires the BQL _and_ the dirty_bitmap_mutex. 713 * Reading from the list can be done with either the BQL or the 714 * dirty_bitmap_mutex. Modifying a bitmap only requires 715 * dirty_bitmap_mutex. */ 716 QemuMutex dirty_bitmap_mutex; 717 QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps; 718 719 /* Offset after the highest byte written to */ 720 Stat64 wr_highest_offset; 721 722 /* If true, copy read backing sectors into image. Can be >1 if more 723 * than one client has requested copy-on-read. Accessed with atomic 724 * ops. 725 */ 726 int copy_on_read; 727 728 /* number of in-flight requests; overall and serialising. 729 * Accessed with atomic ops. 730 */ 731 unsigned int in_flight; 732 unsigned int serialising_in_flight; 733 734 /* Kicked to signal main loop when a request completes. */ 735 AioWait wait; 736 737 /* counter for nested bdrv_io_plug. 738 * Accessed with atomic ops. 739 */ 740 unsigned io_plugged; 741 742 /* do we need to tell the quest if we have a volatile write cache? */ 743 int enable_write_cache; 744 745 /* Accessed with atomic ops. */ 746 int quiesce_counter; 747 int recursive_quiesce_counter; 748 749 unsigned int write_gen; /* Current data generation */ 750 751 /* Protected by reqs_lock. */ 752 CoMutex reqs_lock; 753 QLIST_HEAD(, BdrvTrackedRequest) tracked_requests; 754 CoQueue flush_queue; /* Serializing flush queue */ 755 bool active_flush_req; /* Flush request in flight? */ 756 757 /* Only read/written by whoever has set active_flush_req to true. */ 758 unsigned int flushed_gen; /* Flushed write generation */ 759 }; 760 761 struct BlockBackendRootState { 762 int open_flags; 763 bool read_only; 764 BlockdevDetectZeroesOptions detect_zeroes; 765 }; 766 767 typedef enum BlockMirrorBackingMode { 768 /* Reuse the existing backing chain from the source for the target. 769 * - sync=full: Set backing BDS to NULL. 770 * - sync=top: Use source's backing BDS. 771 * - sync=none: Use source as the backing BDS. */ 772 MIRROR_SOURCE_BACKING_CHAIN, 773 774 /* Open the target's backing chain completely anew */ 775 MIRROR_OPEN_BACKING_CHAIN, 776 777 /* Do not change the target's backing BDS after job completion */ 778 MIRROR_LEAVE_BACKING_CHAIN, 779 } BlockMirrorBackingMode; 780 781 static inline BlockDriverState *backing_bs(BlockDriverState *bs) 782 { 783 return bs->backing ? bs->backing->bs : NULL; 784 } 785 786 787 /* Essential block drivers which must always be statically linked into qemu, and 788 * which therefore can be accessed without using bdrv_find_format() */ 789 extern BlockDriver bdrv_file; 790 extern BlockDriver bdrv_raw; 791 extern BlockDriver bdrv_qcow2; 792 793 int coroutine_fn bdrv_co_preadv(BdrvChild *child, 794 int64_t offset, unsigned int bytes, QEMUIOVector *qiov, 795 BdrvRequestFlags flags); 796 int coroutine_fn bdrv_co_pwritev(BdrvChild *child, 797 int64_t offset, unsigned int bytes, QEMUIOVector *qiov, 798 BdrvRequestFlags flags); 799 800 void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent); 801 void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent); 802 803 int get_tmp_filename(char *filename, int size); 804 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size, 805 const char *filename); 806 807 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, 808 QDict *options); 809 810 811 /** 812 * bdrv_add_before_write_notifier: 813 * 814 * Register a callback that is invoked before write requests are processed but 815 * after any throttling or waiting for overlapping requests. 816 */ 817 void bdrv_add_before_write_notifier(BlockDriverState *bs, 818 NotifierWithReturn *notifier); 819 820 /** 821 * bdrv_detach_aio_context: 822 * 823 * May be called from .bdrv_detach_aio_context() to detach children from the 824 * current #AioContext. This is only needed by block drivers that manage their 825 * own children. Both ->file and ->backing are automatically handled and 826 * block drivers should not call this function on them explicitly. 827 */ 828 void bdrv_detach_aio_context(BlockDriverState *bs); 829 830 /** 831 * bdrv_attach_aio_context: 832 * 833 * May be called from .bdrv_attach_aio_context() to attach children to the new 834 * #AioContext. This is only needed by block drivers that manage their own 835 * children. Both ->file and ->backing are automatically handled and block 836 * drivers should not call this function on them explicitly. 837 */ 838 void bdrv_attach_aio_context(BlockDriverState *bs, 839 AioContext *new_context); 840 841 /** 842 * bdrv_add_aio_context_notifier: 843 * 844 * If a long-running job intends to be always run in the same AioContext as a 845 * certain BDS, it may use this function to be notified of changes regarding the 846 * association of the BDS to an AioContext. 847 * 848 * attached_aio_context() is called after the target BDS has been attached to a 849 * new AioContext; detach_aio_context() is called before the target BDS is being 850 * detached from its old AioContext. 851 */ 852 void bdrv_add_aio_context_notifier(BlockDriverState *bs, 853 void (*attached_aio_context)(AioContext *new_context, void *opaque), 854 void (*detach_aio_context)(void *opaque), void *opaque); 855 856 /** 857 * bdrv_remove_aio_context_notifier: 858 * 859 * Unsubscribe of change notifications regarding the BDS's AioContext. The 860 * parameters given here have to be the same as those given to 861 * bdrv_add_aio_context_notifier(). 862 */ 863 void bdrv_remove_aio_context_notifier(BlockDriverState *bs, 864 void (*aio_context_attached)(AioContext *, 865 void *), 866 void (*aio_context_detached)(void *), 867 void *opaque); 868 869 /** 870 * bdrv_wakeup: 871 * @bs: The BlockDriverState for which an I/O operation has been completed. 872 * 873 * Wake up the main thread if it is waiting on BDRV_POLL_WHILE. During 874 * synchronous I/O on a BlockDriverState that is attached to another 875 * I/O thread, the main thread lets the I/O thread's event loop run, 876 * waiting for the I/O operation to complete. A bdrv_wakeup will wake 877 * up the main thread if necessary. 878 * 879 * Manual calls to bdrv_wakeup are rarely necessary, because 880 * bdrv_dec_in_flight already calls it. 881 */ 882 void bdrv_wakeup(BlockDriverState *bs); 883 884 #ifdef _WIN32 885 int is_windows_drive(const char *filename); 886 #endif 887 888 /** 889 * stream_start: 890 * @job_id: The id of the newly-created job, or %NULL to use the 891 * device name of @bs. 892 * @bs: Block device to operate on. 893 * @base: Block device that will become the new base, or %NULL to 894 * flatten the whole backing file chain onto @bs. 895 * @backing_file_str: The file name that will be written to @bs as the 896 * the new backing file if the job completes. Ignored if @base is %NULL. 897 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 898 * @on_error: The action to take upon error. 899 * @errp: Error object. 900 * 901 * Start a streaming operation on @bs. Clusters that are unallocated 902 * in @bs, but allocated in any image between @base and @bs (both 903 * exclusive) will be written to @bs. At the end of a successful 904 * streaming job, the backing file of @bs will be changed to 905 * @backing_file_str in the written image and to @base in the live 906 * BlockDriverState. 907 */ 908 void stream_start(const char *job_id, BlockDriverState *bs, 909 BlockDriverState *base, const char *backing_file_str, 910 int64_t speed, BlockdevOnError on_error, Error **errp); 911 912 /** 913 * commit_start: 914 * @job_id: The id of the newly-created job, or %NULL to use the 915 * device name of @bs. 916 * @bs: Active block device. 917 * @top: Top block device to be committed. 918 * @base: Block device that will be written into, and become the new top. 919 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 920 * @on_error: The action to take upon error. 921 * @backing_file_str: String to use as the backing file in @top's overlay 922 * @filter_node_name: The node name that should be assigned to the filter 923 * driver that the commit job inserts into the graph above @top. NULL means 924 * that a node name should be autogenerated. 925 * @errp: Error object. 926 * 927 */ 928 void commit_start(const char *job_id, BlockDriverState *bs, 929 BlockDriverState *base, BlockDriverState *top, int64_t speed, 930 BlockdevOnError on_error, const char *backing_file_str, 931 const char *filter_node_name, Error **errp); 932 /** 933 * commit_active_start: 934 * @job_id: The id of the newly-created job, or %NULL to use the 935 * device name of @bs. 936 * @bs: Active block device to be committed. 937 * @base: Block device that will be written into, and become the new top. 938 * @creation_flags: Flags that control the behavior of the Job lifetime. 939 * See @BlockJobCreateFlags 940 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 941 * @on_error: The action to take upon error. 942 * @filter_node_name: The node name that should be assigned to the filter 943 * driver that the commit job inserts into the graph above @bs. NULL means that 944 * a node name should be autogenerated. 945 * @cb: Completion function for the job. 946 * @opaque: Opaque pointer value passed to @cb. 947 * @auto_complete: Auto complete the job. 948 * @errp: Error object. 949 * 950 */ 951 void commit_active_start(const char *job_id, BlockDriverState *bs, 952 BlockDriverState *base, int creation_flags, 953 int64_t speed, BlockdevOnError on_error, 954 const char *filter_node_name, 955 BlockCompletionFunc *cb, void *opaque, 956 bool auto_complete, Error **errp); 957 /* 958 * mirror_start: 959 * @job_id: The id of the newly-created job, or %NULL to use the 960 * device name of @bs. 961 * @bs: Block device to operate on. 962 * @target: Block device to write to. 963 * @replaces: Block graph node name to replace once the mirror is done. Can 964 * only be used when full mirroring is selected. 965 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 966 * @granularity: The chosen granularity for the dirty bitmap. 967 * @buf_size: The amount of data that can be in flight at one time. 968 * @mode: Whether to collapse all images in the chain to the target. 969 * @backing_mode: How to establish the target's backing chain after completion. 970 * @on_source_error: The action to take upon error reading from the source. 971 * @on_target_error: The action to take upon error writing to the target. 972 * @unmap: Whether to unmap target where source sectors only contain zeroes. 973 * @filter_node_name: The node name that should be assigned to the filter 974 * driver that the mirror job inserts into the graph above @bs. NULL means that 975 * a node name should be autogenerated. 976 * @errp: Error object. 977 * 978 * Start a mirroring operation on @bs. Clusters that are allocated 979 * in @bs will be written to @target until the job is cancelled or 980 * manually completed. At the end of a successful mirroring job, 981 * @bs will be switched to read from @target. 982 */ 983 void mirror_start(const char *job_id, BlockDriverState *bs, 984 BlockDriverState *target, const char *replaces, 985 int64_t speed, uint32_t granularity, int64_t buf_size, 986 MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, 987 BlockdevOnError on_source_error, 988 BlockdevOnError on_target_error, 989 bool unmap, const char *filter_node_name, Error **errp); 990 991 /* 992 * backup_job_create: 993 * @job_id: The id of the newly-created job, or %NULL to use the 994 * device name of @bs. 995 * @bs: Block device to operate on. 996 * @target: Block device to write to. 997 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 998 * @sync_mode: What parts of the disk image should be copied to the destination. 999 * @sync_bitmap: The dirty bitmap if sync_mode is MIRROR_SYNC_MODE_INCREMENTAL. 1000 * @on_source_error: The action to take upon error reading from the source. 1001 * @on_target_error: The action to take upon error writing to the target. 1002 * @creation_flags: Flags that control the behavior of the Job lifetime. 1003 * See @BlockJobCreateFlags 1004 * @cb: Completion function for the job. 1005 * @opaque: Opaque pointer value passed to @cb. 1006 * @txn: Transaction that this job is part of (may be NULL). 1007 * 1008 * Create a backup operation on @bs. Clusters in @bs are written to @target 1009 * until the job is cancelled or manually completed. 1010 */ 1011 BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, 1012 BlockDriverState *target, int64_t speed, 1013 MirrorSyncMode sync_mode, 1014 BdrvDirtyBitmap *sync_bitmap, 1015 bool compress, 1016 BlockdevOnError on_source_error, 1017 BlockdevOnError on_target_error, 1018 int creation_flags, 1019 BlockCompletionFunc *cb, void *opaque, 1020 BlockJobTxn *txn, Error **errp); 1021 1022 void hmp_drive_add_node(Monitor *mon, const char *optstr); 1023 1024 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, 1025 const char *child_name, 1026 const BdrvChildRole *child_role, 1027 uint64_t perm, uint64_t shared_perm, 1028 void *opaque, Error **errp); 1029 void bdrv_root_unref_child(BdrvChild *child); 1030 1031 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, 1032 Error **errp); 1033 1034 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by 1035 * block filters: Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED and RESIZE to 1036 * all children */ 1037 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c, 1038 const BdrvChildRole *role, 1039 BlockReopenQueue *reopen_queue, 1040 uint64_t perm, uint64_t shared, 1041 uint64_t *nperm, uint64_t *nshared); 1042 1043 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by 1044 * (non-raw) image formats: Like above for bs->backing, but for bs->file it 1045 * requires WRITE | RESIZE for read-write images, always requires 1046 * CONSISTENT_READ and doesn't share WRITE. */ 1047 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c, 1048 const BdrvChildRole *role, 1049 BlockReopenQueue *reopen_queue, 1050 uint64_t perm, uint64_t shared, 1051 uint64_t *nperm, uint64_t *nshared); 1052 1053 /* 1054 * Default implementation for drivers to pass bdrv_co_block_status() to 1055 * their file. 1056 */ 1057 int coroutine_fn bdrv_co_block_status_from_file(BlockDriverState *bs, 1058 bool want_zero, 1059 int64_t offset, 1060 int64_t bytes, 1061 int64_t *pnum, 1062 int64_t *map, 1063 BlockDriverState **file); 1064 /* 1065 * Default implementation for drivers to pass bdrv_co_block_status() to 1066 * their backing file. 1067 */ 1068 int coroutine_fn bdrv_co_block_status_from_backing(BlockDriverState *bs, 1069 bool want_zero, 1070 int64_t offset, 1071 int64_t bytes, 1072 int64_t *pnum, 1073 int64_t *map, 1074 BlockDriverState **file); 1075 const char *bdrv_get_parent_name(const BlockDriverState *bs); 1076 void blk_dev_change_media_cb(BlockBackend *blk, bool load, Error **errp); 1077 bool blk_dev_has_removable_media(BlockBackend *blk); 1078 bool blk_dev_has_tray(BlockBackend *blk); 1079 void blk_dev_eject_request(BlockBackend *blk, bool force); 1080 bool blk_dev_is_tray_open(BlockBackend *blk); 1081 bool blk_dev_is_medium_locked(BlockBackend *blk); 1082 1083 void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes); 1084 1085 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out); 1086 void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in); 1087 1088 void bdrv_inc_in_flight(BlockDriverState *bs); 1089 void bdrv_dec_in_flight(BlockDriverState *bs); 1090 1091 void blockdev_close_all_bdrv_states(void); 1092 1093 #endif /* BLOCK_INT_H */ 1094