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