1 /* 2 * Copyright (C) 2001 Sistina Software (UK) Limited. 3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. 4 * 5 * This file is released under the LGPL. 6 */ 7 8 #ifndef _LINUX_DEVICE_MAPPER_H 9 #define _LINUX_DEVICE_MAPPER_H 10 11 #include <linux/bio.h> 12 #include <linux/blkdev.h> 13 #include <linux/dm-ioctl.h> 14 #include <linux/math64.h> 15 #include <linux/ratelimit.h> 16 17 struct dm_dev; 18 struct dm_target; 19 struct dm_table; 20 struct dm_report_zones_args; 21 struct mapped_device; 22 struct bio_vec; 23 enum dax_access_mode; 24 25 /* 26 * Type of table, mapped_device's mempool and request_queue 27 */ 28 enum dm_queue_mode { 29 DM_TYPE_NONE = 0, 30 DM_TYPE_BIO_BASED = 1, 31 DM_TYPE_REQUEST_BASED = 2, 32 DM_TYPE_DAX_BIO_BASED = 3, 33 }; 34 35 typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE, STATUSTYPE_IMA } status_type_t; 36 37 union map_info { 38 void *ptr; 39 }; 40 41 /* 42 * In the constructor the target parameter will already have the 43 * table, type, begin and len fields filled in. 44 */ 45 typedef int (*dm_ctr_fn) (struct dm_target *target, 46 unsigned int argc, char **argv); 47 48 /* 49 * The destructor doesn't need to free the dm_target, just 50 * anything hidden ti->private. 51 */ 52 typedef void (*dm_dtr_fn) (struct dm_target *ti); 53 54 /* 55 * The map function must return: 56 * < 0: error 57 * = 0: The target will handle the io by resubmitting it later 58 * = 1: simple remap complete 59 * = 2: The target wants to push back the io 60 */ 61 typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio); 62 typedef int (*dm_clone_and_map_request_fn) (struct dm_target *ti, 63 struct request *rq, 64 union map_info *map_context, 65 struct request **clone); 66 typedef void (*dm_release_clone_request_fn) (struct request *clone, 67 union map_info *map_context); 68 69 /* 70 * Returns: 71 * < 0 : error (currently ignored) 72 * 0 : ended successfully 73 * 1 : for some reason the io has still not completed (eg, 74 * multipath target might want to requeue a failed io). 75 * 2 : The target wants to push back the io 76 */ 77 typedef int (*dm_endio_fn) (struct dm_target *ti, 78 struct bio *bio, blk_status_t *error); 79 typedef int (*dm_request_endio_fn) (struct dm_target *ti, 80 struct request *clone, blk_status_t error, 81 union map_info *map_context); 82 83 typedef void (*dm_presuspend_fn) (struct dm_target *ti); 84 typedef void (*dm_presuspend_undo_fn) (struct dm_target *ti); 85 typedef void (*dm_postsuspend_fn) (struct dm_target *ti); 86 typedef int (*dm_preresume_fn) (struct dm_target *ti); 87 typedef void (*dm_resume_fn) (struct dm_target *ti); 88 89 typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type, 90 unsigned status_flags, char *result, unsigned maxlen); 91 92 typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv, 93 char *result, unsigned maxlen); 94 95 typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti, struct block_device **bdev); 96 97 #ifdef CONFIG_BLK_DEV_ZONED 98 typedef int (*dm_report_zones_fn) (struct dm_target *ti, 99 struct dm_report_zones_args *args, 100 unsigned int nr_zones); 101 #else 102 /* 103 * Define dm_report_zones_fn so that targets can assign to NULL if 104 * CONFIG_BLK_DEV_ZONED disabled. Otherwise each target needs to do 105 * awkward #ifdefs in their target_type, etc. 106 */ 107 typedef int (*dm_report_zones_fn) (struct dm_target *dummy); 108 #endif 109 110 /* 111 * These iteration functions are typically used to check (and combine) 112 * properties of underlying devices. 113 * E.g. Does at least one underlying device support flush? 114 * Does any underlying device not support WRITE_SAME? 115 * 116 * The callout function is called once for each contiguous section of 117 * an underlying device. State can be maintained in *data. 118 * Return non-zero to stop iterating through any further devices. 119 */ 120 typedef int (*iterate_devices_callout_fn) (struct dm_target *ti, 121 struct dm_dev *dev, 122 sector_t start, sector_t len, 123 void *data); 124 125 /* 126 * This function must iterate through each section of device used by the 127 * target until it encounters a non-zero return code, which it then returns. 128 * Returns zero if no callout returned non-zero. 129 */ 130 typedef int (*dm_iterate_devices_fn) (struct dm_target *ti, 131 iterate_devices_callout_fn fn, 132 void *data); 133 134 typedef void (*dm_io_hints_fn) (struct dm_target *ti, 135 struct queue_limits *limits); 136 137 /* 138 * Returns: 139 * 0: The target can handle the next I/O immediately. 140 * 1: The target can't handle the next I/O immediately. 141 */ 142 typedef int (*dm_busy_fn) (struct dm_target *ti); 143 144 /* 145 * Returns: 146 * < 0 : error 147 * >= 0 : the number of bytes accessible at the address 148 */ 149 typedef long (*dm_dax_direct_access_fn) (struct dm_target *ti, pgoff_t pgoff, 150 long nr_pages, enum dax_access_mode node, void **kaddr, 151 pfn_t *pfn); 152 typedef int (*dm_dax_zero_page_range_fn)(struct dm_target *ti, pgoff_t pgoff, 153 size_t nr_pages); 154 155 /* 156 * Returns: 157 * != 0 : number of bytes transferred 158 * 0 : recovery write failed 159 */ 160 typedef size_t (*dm_dax_recovery_write_fn)(struct dm_target *ti, pgoff_t pgoff, 161 void *addr, size_t bytes, struct iov_iter *i); 162 163 void dm_error(const char *message); 164 165 struct dm_dev { 166 struct block_device *bdev; 167 struct dax_device *dax_dev; 168 fmode_t mode; 169 char name[16]; 170 }; 171 172 dev_t dm_get_dev_t(const char *path); 173 174 /* 175 * Constructors should call these functions to ensure destination devices 176 * are opened/closed correctly. 177 */ 178 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, 179 struct dm_dev **result); 180 void dm_put_device(struct dm_target *ti, struct dm_dev *d); 181 182 /* 183 * Information about a target type 184 */ 185 186 struct target_type { 187 uint64_t features; 188 const char *name; 189 struct module *module; 190 unsigned version[3]; 191 dm_ctr_fn ctr; 192 dm_dtr_fn dtr; 193 dm_map_fn map; 194 dm_clone_and_map_request_fn clone_and_map_rq; 195 dm_release_clone_request_fn release_clone_rq; 196 dm_endio_fn end_io; 197 dm_request_endio_fn rq_end_io; 198 dm_presuspend_fn presuspend; 199 dm_presuspend_undo_fn presuspend_undo; 200 dm_postsuspend_fn postsuspend; 201 dm_preresume_fn preresume; 202 dm_resume_fn resume; 203 dm_status_fn status; 204 dm_message_fn message; 205 dm_prepare_ioctl_fn prepare_ioctl; 206 dm_report_zones_fn report_zones; 207 dm_busy_fn busy; 208 dm_iterate_devices_fn iterate_devices; 209 dm_io_hints_fn io_hints; 210 dm_dax_direct_access_fn direct_access; 211 dm_dax_zero_page_range_fn dax_zero_page_range; 212 dm_dax_recovery_write_fn dax_recovery_write; 213 214 /* For internal device-mapper use. */ 215 struct list_head list; 216 }; 217 218 /* 219 * Target features 220 */ 221 222 /* 223 * Any table that contains an instance of this target must have only one. 224 */ 225 #define DM_TARGET_SINGLETON 0x00000001 226 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON) 227 228 /* 229 * Indicates that a target does not support read-only devices. 230 */ 231 #define DM_TARGET_ALWAYS_WRITEABLE 0x00000002 232 #define dm_target_always_writeable(type) \ 233 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE) 234 235 /* 236 * Any device that contains a table with an instance of this target may never 237 * have tables containing any different target type. 238 */ 239 #define DM_TARGET_IMMUTABLE 0x00000004 240 #define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE) 241 242 /* 243 * Indicates that a target may replace any target; even immutable targets. 244 * .map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined. 245 */ 246 #define DM_TARGET_WILDCARD 0x00000008 247 #define dm_target_is_wildcard(type) ((type)->features & DM_TARGET_WILDCARD) 248 249 /* 250 * A target implements own bio data integrity. 251 */ 252 #define DM_TARGET_INTEGRITY 0x00000010 253 #define dm_target_has_integrity(type) ((type)->features & DM_TARGET_INTEGRITY) 254 255 /* 256 * A target passes integrity data to the lower device. 257 */ 258 #define DM_TARGET_PASSES_INTEGRITY 0x00000020 259 #define dm_target_passes_integrity(type) ((type)->features & DM_TARGET_PASSES_INTEGRITY) 260 261 /* 262 * Indicates support for zoned block devices: 263 * - DM_TARGET_ZONED_HM: the target also supports host-managed zoned 264 * block devices but does not support combining different zoned models. 265 * - DM_TARGET_MIXED_ZONED_MODEL: the target supports combining multiple 266 * devices with different zoned models. 267 */ 268 #ifdef CONFIG_BLK_DEV_ZONED 269 #define DM_TARGET_ZONED_HM 0x00000040 270 #define dm_target_supports_zoned_hm(type) ((type)->features & DM_TARGET_ZONED_HM) 271 #else 272 #define DM_TARGET_ZONED_HM 0x00000000 273 #define dm_target_supports_zoned_hm(type) (false) 274 #endif 275 276 /* 277 * A target handles REQ_NOWAIT 278 */ 279 #define DM_TARGET_NOWAIT 0x00000080 280 #define dm_target_supports_nowait(type) ((type)->features & DM_TARGET_NOWAIT) 281 282 /* 283 * A target supports passing through inline crypto support. 284 */ 285 #define DM_TARGET_PASSES_CRYPTO 0x00000100 286 #define dm_target_passes_crypto(type) ((type)->features & DM_TARGET_PASSES_CRYPTO) 287 288 #ifdef CONFIG_BLK_DEV_ZONED 289 #define DM_TARGET_MIXED_ZONED_MODEL 0x00000200 290 #define dm_target_supports_mixed_zoned_model(type) \ 291 ((type)->features & DM_TARGET_MIXED_ZONED_MODEL) 292 #else 293 #define DM_TARGET_MIXED_ZONED_MODEL 0x00000000 294 #define dm_target_supports_mixed_zoned_model(type) (false) 295 #endif 296 297 struct dm_target { 298 struct dm_table *table; 299 struct target_type *type; 300 301 /* target limits */ 302 sector_t begin; 303 sector_t len; 304 305 /* If non-zero, maximum size of I/O submitted to a target. */ 306 uint32_t max_io_len; 307 308 /* 309 * A number of zero-length barrier bios that will be submitted 310 * to the target for the purpose of flushing cache. 311 * 312 * The bio number can be accessed with dm_bio_get_target_bio_nr. 313 * It is a responsibility of the target driver to remap these bios 314 * to the real underlying devices. 315 */ 316 unsigned num_flush_bios; 317 318 /* 319 * The number of discard bios that will be submitted to the target. 320 * The bio number can be accessed with dm_bio_get_target_bio_nr. 321 */ 322 unsigned num_discard_bios; 323 324 /* 325 * The number of secure erase bios that will be submitted to the target. 326 * The bio number can be accessed with dm_bio_get_target_bio_nr. 327 */ 328 unsigned num_secure_erase_bios; 329 330 /* 331 * The number of WRITE ZEROES bios that will be submitted to the target. 332 * The bio number can be accessed with dm_bio_get_target_bio_nr. 333 */ 334 unsigned num_write_zeroes_bios; 335 336 /* 337 * The minimum number of extra bytes allocated in each io for the 338 * target to use. 339 */ 340 unsigned per_io_data_size; 341 342 /* target specific data */ 343 void *private; 344 345 /* Used to provide an error string from the ctr */ 346 char *error; 347 348 /* 349 * Set if this target needs to receive flushes regardless of 350 * whether or not its underlying devices have support. 351 */ 352 bool flush_supported:1; 353 354 /* 355 * Set if this target needs to receive discards regardless of 356 * whether or not its underlying devices have support. 357 */ 358 bool discards_supported:1; 359 360 /* 361 * Set if we need to limit the number of in-flight bios when swapping. 362 */ 363 bool limit_swap_bios:1; 364 365 /* 366 * Set if this target implements a zoned device and needs emulation of 367 * zone append operations using regular writes. 368 */ 369 bool emulate_zone_append:1; 370 371 /* 372 * Set if the target will submit IO using dm_submit_bio_remap() 373 * after returning DM_MAPIO_SUBMITTED from its map function. 374 */ 375 bool accounts_remapped_io:1; 376 }; 377 378 void *dm_per_bio_data(struct bio *bio, size_t data_size); 379 struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size); 380 unsigned dm_bio_get_target_bio_nr(const struct bio *bio); 381 382 u64 dm_start_time_ns_from_clone(struct bio *bio); 383 384 int dm_register_target(struct target_type *t); 385 void dm_unregister_target(struct target_type *t); 386 387 /* 388 * Target argument parsing. 389 */ 390 struct dm_arg_set { 391 unsigned argc; 392 char **argv; 393 }; 394 395 /* 396 * The minimum and maximum value of a numeric argument, together with 397 * the error message to use if the number is found to be outside that range. 398 */ 399 struct dm_arg { 400 unsigned min; 401 unsigned max; 402 char *error; 403 }; 404 405 /* 406 * Validate the next argument, either returning it as *value or, if invalid, 407 * returning -EINVAL and setting *error. 408 */ 409 int dm_read_arg(const struct dm_arg *arg, struct dm_arg_set *arg_set, 410 unsigned *value, char **error); 411 412 /* 413 * Process the next argument as the start of a group containing between 414 * arg->min and arg->max further arguments. Either return the size as 415 * *num_args or, if invalid, return -EINVAL and set *error. 416 */ 417 int dm_read_arg_group(const struct dm_arg *arg, struct dm_arg_set *arg_set, 418 unsigned *num_args, char **error); 419 420 /* 421 * Return the current argument and shift to the next. 422 */ 423 const char *dm_shift_arg(struct dm_arg_set *as); 424 425 /* 426 * Move through num_args arguments. 427 */ 428 void dm_consume_args(struct dm_arg_set *as, unsigned num_args); 429 430 /*----------------------------------------------------------------- 431 * Functions for creating and manipulating mapped devices. 432 * Drop the reference with dm_put when you finish with the object. 433 *---------------------------------------------------------------*/ 434 435 /* 436 * DM_ANY_MINOR chooses the next available minor number. 437 */ 438 #define DM_ANY_MINOR (-1) 439 int dm_create(int minor, struct mapped_device **md); 440 441 /* 442 * Reference counting for md. 443 */ 444 struct mapped_device *dm_get_md(dev_t dev); 445 void dm_get(struct mapped_device *md); 446 int dm_hold(struct mapped_device *md); 447 void dm_put(struct mapped_device *md); 448 449 /* 450 * An arbitrary pointer may be stored alongside a mapped device. 451 */ 452 void dm_set_mdptr(struct mapped_device *md, void *ptr); 453 void *dm_get_mdptr(struct mapped_device *md); 454 455 /* 456 * A device can still be used while suspended, but I/O is deferred. 457 */ 458 int dm_suspend(struct mapped_device *md, unsigned suspend_flags); 459 int dm_resume(struct mapped_device *md); 460 461 /* 462 * Event functions. 463 */ 464 uint32_t dm_get_event_nr(struct mapped_device *md); 465 int dm_wait_event(struct mapped_device *md, int event_nr); 466 uint32_t dm_next_uevent_seq(struct mapped_device *md); 467 void dm_uevent_add(struct mapped_device *md, struct list_head *elist); 468 469 /* 470 * Info functions. 471 */ 472 const char *dm_device_name(struct mapped_device *md); 473 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid); 474 struct gendisk *dm_disk(struct mapped_device *md); 475 int dm_suspended(struct dm_target *ti); 476 int dm_post_suspending(struct dm_target *ti); 477 int dm_noflush_suspending(struct dm_target *ti); 478 void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors); 479 void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone); 480 union map_info *dm_get_rq_mapinfo(struct request *rq); 481 482 #ifdef CONFIG_BLK_DEV_ZONED 483 struct dm_report_zones_args { 484 struct dm_target *tgt; 485 sector_t next_sector; 486 487 void *orig_data; 488 report_zones_cb orig_cb; 489 unsigned int zone_idx; 490 491 /* must be filled by ->report_zones before calling dm_report_zones_cb */ 492 sector_t start; 493 }; 494 int dm_report_zones(struct block_device *bdev, sector_t start, sector_t sector, 495 struct dm_report_zones_args *args, unsigned int nr_zones); 496 #endif /* CONFIG_BLK_DEV_ZONED */ 497 498 /* 499 * Device mapper functions to parse and create devices specified by the 500 * parameter "dm-mod.create=" 501 */ 502 int __init dm_early_create(struct dm_ioctl *dmi, 503 struct dm_target_spec **spec_array, 504 char **target_params_array); 505 506 struct queue_limits *dm_get_queue_limits(struct mapped_device *md); 507 508 /* 509 * Geometry functions. 510 */ 511 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo); 512 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo); 513 514 /*----------------------------------------------------------------- 515 * Functions for manipulating device-mapper tables. 516 *---------------------------------------------------------------*/ 517 518 /* 519 * First create an empty table. 520 */ 521 int dm_table_create(struct dm_table **result, fmode_t mode, 522 unsigned num_targets, struct mapped_device *md); 523 524 /* 525 * Then call this once for each target. 526 */ 527 int dm_table_add_target(struct dm_table *t, const char *type, 528 sector_t start, sector_t len, char *params); 529 530 /* 531 * Target can use this to set the table's type. 532 * Can only ever be called from a target's ctr. 533 * Useful for "hybrid" target (supports both bio-based 534 * and request-based). 535 */ 536 void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type); 537 538 /* 539 * Finally call this to make the table ready for use. 540 */ 541 int dm_table_complete(struct dm_table *t); 542 543 /* 544 * Destroy the table when finished. 545 */ 546 void dm_table_destroy(struct dm_table *t); 547 548 /* 549 * Target may require that it is never sent I/O larger than len. 550 */ 551 int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len); 552 553 /* 554 * Table reference counting. 555 */ 556 struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx); 557 void dm_put_live_table(struct mapped_device *md, int srcu_idx); 558 void dm_sync_table(struct mapped_device *md); 559 560 /* 561 * Queries 562 */ 563 sector_t dm_table_get_size(struct dm_table *t); 564 unsigned int dm_table_get_num_targets(struct dm_table *t); 565 fmode_t dm_table_get_mode(struct dm_table *t); 566 struct mapped_device *dm_table_get_md(struct dm_table *t); 567 const char *dm_table_device_name(struct dm_table *t); 568 569 /* 570 * Trigger an event. 571 */ 572 void dm_table_event(struct dm_table *t); 573 574 /* 575 * Run the queue for request-based targets. 576 */ 577 void dm_table_run_md_queue_async(struct dm_table *t); 578 579 /* 580 * The device must be suspended before calling this method. 581 * Returns the previous table, which the caller must destroy. 582 */ 583 struct dm_table *dm_swap_table(struct mapped_device *md, 584 struct dm_table *t); 585 586 /* 587 * Table blk_crypto_profile functions 588 */ 589 void dm_destroy_crypto_profile(struct blk_crypto_profile *profile); 590 591 /*----------------------------------------------------------------- 592 * Macros. 593 *---------------------------------------------------------------*/ 594 #define DM_NAME "device-mapper" 595 596 #define DM_FMT(fmt) DM_NAME ": " DM_MSG_PREFIX ": " fmt "\n" 597 598 #define DMCRIT(fmt, ...) pr_crit(DM_FMT(fmt), ##__VA_ARGS__) 599 600 #define DMERR(fmt, ...) pr_err(DM_FMT(fmt), ##__VA_ARGS__) 601 #define DMERR_LIMIT(fmt, ...) pr_err_ratelimited(DM_FMT(fmt), ##__VA_ARGS__) 602 #define DMWARN(fmt, ...) pr_warn(DM_FMT(fmt), ##__VA_ARGS__) 603 #define DMWARN_LIMIT(fmt, ...) pr_warn_ratelimited(DM_FMT(fmt), ##__VA_ARGS__) 604 #define DMINFO(fmt, ...) pr_info(DM_FMT(fmt), ##__VA_ARGS__) 605 #define DMINFO_LIMIT(fmt, ...) pr_info_ratelimited(DM_FMT(fmt), ##__VA_ARGS__) 606 607 #define DMDEBUG(fmt, ...) pr_debug(DM_FMT(fmt), ##__VA_ARGS__) 608 #define DMDEBUG_LIMIT(fmt, ...) pr_debug_ratelimited(DM_FMT(fmt), ##__VA_ARGS__) 609 610 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \ 611 0 : scnprintf(result + sz, maxlen - sz, x)) 612 613 #define DMEMIT_TARGET_NAME_VERSION(y) \ 614 DMEMIT("target_name=%s,target_version=%u.%u.%u", \ 615 (y)->name, (y)->version[0], (y)->version[1], (y)->version[2]) 616 617 /* 618 * Definitions of return values from target end_io function. 619 */ 620 #define DM_ENDIO_DONE 0 621 #define DM_ENDIO_INCOMPLETE 1 622 #define DM_ENDIO_REQUEUE 2 623 #define DM_ENDIO_DELAY_REQUEUE 3 624 625 /* 626 * Definitions of return values from target map function. 627 */ 628 #define DM_MAPIO_SUBMITTED 0 629 #define DM_MAPIO_REMAPPED 1 630 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE 631 #define DM_MAPIO_DELAY_REQUEUE DM_ENDIO_DELAY_REQUEUE 632 #define DM_MAPIO_KILL 4 633 634 #define dm_sector_div64(x, y)( \ 635 { \ 636 u64 _res; \ 637 (x) = div64_u64_rem(x, y, &_res); \ 638 _res; \ 639 } \ 640 ) 641 642 /* 643 * Ceiling(n / sz) 644 */ 645 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz)) 646 647 #define dm_sector_div_up(n, sz) ( \ 648 { \ 649 sector_t _r = ((n) + (sz) - 1); \ 650 sector_div(_r, (sz)); \ 651 _r; \ 652 } \ 653 ) 654 655 /* 656 * ceiling(n / size) * size 657 */ 658 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz)) 659 660 /* 661 * Sector offset taken relative to the start of the target instead of 662 * relative to the start of the device. 663 */ 664 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin) 665 666 static inline sector_t to_sector(unsigned long long n) 667 { 668 return (n >> SECTOR_SHIFT); 669 } 670 671 static inline unsigned long to_bytes(sector_t n) 672 { 673 return (n << SECTOR_SHIFT); 674 } 675 676 #endif /* _LINUX_DEVICE_MAPPER_H */ 677