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