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