2 * Copyright (C) 2001 Sistina Software (UK) Limited.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
5 * This file is released under the LGPL.
8 #ifndef _LINUX_DEVICE_MAPPER_H
9 #define _LINUX_DEVICE_MAPPER_H
11 #include <linux/bio.h>
12 #include <linux/blkdev.h>
13 #include <linux/math64.h>
14 #include <linux/ratelimit.h>
23 * Type of table, mapped_device's mempool and request_queue
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,
33 typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
40 * In the constructor the target parameter will already have the
41 * table, type, begin and len fields filled in.
43 typedef int (*dm_ctr_fn) (struct dm_target *target,
44 unsigned int argc, char **argv);
47 * The destructor doesn't need to free the dm_target, just
48 * anything hidden ti->private.
50 typedef void (*dm_dtr_fn) (struct dm_target *ti);
53 * The map function must return:
55 * = 0: The target will handle the io by resubmitting it later
56 * = 1: simple remap complete
57 * = 2: The target wants to push back the io
59 typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
60 typedef int (*dm_clone_and_map_request_fn) (struct dm_target *ti,
62 union map_info *map_context,
63 struct request **clone);
64 typedef void (*dm_release_clone_request_fn) (struct request *clone);
68 * < 0 : error (currently ignored)
69 * 0 : ended successfully
70 * 1 : for some reason the io has still not completed (eg,
71 * multipath target might want to requeue a failed io).
72 * 2 : The target wants to push back the io
74 typedef int (*dm_endio_fn) (struct dm_target *ti,
75 struct bio *bio, int error);
76 typedef int (*dm_request_endio_fn) (struct dm_target *ti,
77 struct request *clone, int error,
78 union map_info *map_context);
80 typedef void (*dm_presuspend_fn) (struct dm_target *ti);
81 typedef void (*dm_presuspend_undo_fn) (struct dm_target *ti);
82 typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
83 typedef int (*dm_preresume_fn) (struct dm_target *ti);
84 typedef void (*dm_resume_fn) (struct dm_target *ti);
86 typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
87 unsigned status_flags, char *result, unsigned maxlen);
89 typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
91 typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti,
92 struct block_device **bdev, fmode_t *mode);
95 * These iteration functions are typically used to check (and combine)
96 * properties of underlying devices.
97 * E.g. Does at least one underlying device support flush?
98 * Does any underlying device not support WRITE_SAME?
100 * The callout function is called once for each contiguous section of
101 * an underlying device. State can be maintained in *data.
102 * Return non-zero to stop iterating through any further devices.
104 typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
106 sector_t start, sector_t len,
110 * This function must iterate through each section of device used by the
111 * target until it encounters a non-zero return code, which it then returns.
112 * Returns zero if no callout returned non-zero.
114 typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
115 iterate_devices_callout_fn fn,
118 typedef void (*dm_io_hints_fn) (struct dm_target *ti,
119 struct queue_limits *limits);
123 * 0: The target can handle the next I/O immediately.
124 * 1: The target can't handle the next I/O immediately.
126 typedef int (*dm_busy_fn) (struct dm_target *ti);
131 * >= 0 : the number of bytes accessible at the address
133 typedef long (*dm_dax_direct_access_fn) (struct dm_target *ti, pgoff_t pgoff,
134 long nr_pages, void **kaddr, pfn_t *pfn);
135 #define PAGE_SECTORS (PAGE_SIZE / 512)
137 void dm_error(const char *message);
140 struct block_device *bdev;
141 struct dax_device *dax_dev;
146 dev_t dm_get_dev_t(const char *path);
149 * Constructors should call these functions to ensure destination devices
150 * are opened/closed correctly.
152 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
153 struct dm_dev **result);
154 void dm_put_device(struct dm_target *ti, struct dm_dev *d);
157 * Information about a target type
163 struct module *module;
168 dm_clone_and_map_request_fn clone_and_map_rq;
169 dm_release_clone_request_fn release_clone_rq;
171 dm_request_endio_fn rq_end_io;
172 dm_presuspend_fn presuspend;
173 dm_presuspend_undo_fn presuspend_undo;
174 dm_postsuspend_fn postsuspend;
175 dm_preresume_fn preresume;
178 dm_message_fn message;
179 dm_prepare_ioctl_fn prepare_ioctl;
181 dm_iterate_devices_fn iterate_devices;
182 dm_io_hints_fn io_hints;
183 dm_dax_direct_access_fn direct_access;
185 /* For internal device-mapper use. */
186 struct list_head list;
194 * Any table that contains an instance of this target must have only one.
196 #define DM_TARGET_SINGLETON 0x00000001
197 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
200 * Indicates that a target does not support read-only devices.
202 #define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
203 #define dm_target_always_writeable(type) \
204 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
207 * Any device that contains a table with an instance of this target may never
208 * have tables containing any different target type.
210 #define DM_TARGET_IMMUTABLE 0x00000004
211 #define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
214 * Indicates that a target may replace any target; even immutable targets.
215 * .map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined.
217 #define DM_TARGET_WILDCARD 0x00000008
218 #define dm_target_is_wildcard(type) ((type)->features & DM_TARGET_WILDCARD)
221 * Some targets need to be sent the same WRITE bio severals times so
222 * that they can send copies of it to different devices. This function
223 * examines any supplied bio and returns the number of copies of it the
226 typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio *bio);
229 * A target implements own bio data integrity.
231 #define DM_TARGET_INTEGRITY 0x00000010
232 #define dm_target_has_integrity(type) ((type)->features & DM_TARGET_INTEGRITY)
235 * A target passes integrity data to the lower device.
237 #define DM_TARGET_PASSES_INTEGRITY 0x00000020
238 #define dm_target_passes_integrity(type) ((type)->features & DM_TARGET_PASSES_INTEGRITY)
241 struct dm_table *table;
242 struct target_type *type;
248 /* If non-zero, maximum size of I/O submitted to a target. */
252 * A number of zero-length barrier bios that will be submitted
253 * to the target for the purpose of flushing cache.
255 * The bio number can be accessed with dm_bio_get_target_bio_nr.
256 * It is a responsibility of the target driver to remap these bios
257 * to the real underlying devices.
259 unsigned num_flush_bios;
262 * The number of discard bios that will be submitted to the target.
263 * The bio number can be accessed with dm_bio_get_target_bio_nr.
265 unsigned num_discard_bios;
268 * The number of WRITE SAME bios that will be submitted to the target.
269 * The bio number can be accessed with dm_bio_get_target_bio_nr.
271 unsigned num_write_same_bios;
274 * The number of WRITE ZEROES bios that will be submitted to the target.
275 * The bio number can be accessed with dm_bio_get_target_bio_nr.
277 unsigned num_write_zeroes_bios;
280 * The minimum number of extra bytes allocated in each io for the
283 unsigned per_io_data_size;
286 * If defined, this function is called to find out how many
287 * duplicate bios should be sent to the target when writing
290 dm_num_write_bios_fn num_write_bios;
292 /* target specific data */
295 /* Used to provide an error string from the ctr */
299 * Set if this target needs to receive flushes regardless of
300 * whether or not its underlying devices have support.
302 bool flush_supported:1;
305 * Set if this target needs to receive discards regardless of
306 * whether or not its underlying devices have support.
308 bool discards_supported:1;
311 * Set if the target required discard bios to be split
312 * on max_io_len boundary.
314 bool split_discard_bios:1;
317 /* Each target can link one of these into the table */
318 struct dm_target_callbacks {
319 struct list_head list;
320 int (*congested_fn) (struct dm_target_callbacks *, int);
325 * One of these is allocated for each bio.
326 * This structure shouldn't be touched directly by target drivers.
327 * It is here so that we can inline dm_per_bio_data and
328 * dm_bio_from_per_bio_data
330 struct dm_target_io {
332 struct dm_target *ti;
333 unsigned target_bio_nr;
338 static inline void *dm_per_bio_data(struct bio *bio, size_t data_size)
340 return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
343 static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
345 return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
348 static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
350 return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
353 int dm_register_target(struct target_type *t);
354 void dm_unregister_target(struct target_type *t);
357 * Target argument parsing.
365 * The minimum and maximum value of a numeric argument, together with
366 * the error message to use if the number is found to be outside that range.
375 * Validate the next argument, either returning it as *value or, if invalid,
376 * returning -EINVAL and setting *error.
378 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
379 unsigned *value, char **error);
382 * Process the next argument as the start of a group containing between
383 * arg->min and arg->max further arguments. Either return the size as
384 * *num_args or, if invalid, return -EINVAL and set *error.
386 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
387 unsigned *num_args, char **error);
390 * Return the current argument and shift to the next.
392 const char *dm_shift_arg(struct dm_arg_set *as);
395 * Move through num_args arguments.
397 void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
399 /*-----------------------------------------------------------------
400 * Functions for creating and manipulating mapped devices.
401 * Drop the reference with dm_put when you finish with the object.
402 *---------------------------------------------------------------*/
405 * DM_ANY_MINOR chooses the next available minor number.
407 #define DM_ANY_MINOR (-1)
408 int dm_create(int minor, struct mapped_device **md);
411 * Reference counting for md.
413 struct mapped_device *dm_get_md(dev_t dev);
414 void dm_get(struct mapped_device *md);
415 int dm_hold(struct mapped_device *md);
416 void dm_put(struct mapped_device *md);
419 * An arbitrary pointer may be stored alongside a mapped device.
421 void dm_set_mdptr(struct mapped_device *md, void *ptr);
422 void *dm_get_mdptr(struct mapped_device *md);
425 * A device can still be used while suspended, but I/O is deferred.
427 int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
428 int dm_resume(struct mapped_device *md);
433 uint32_t dm_get_event_nr(struct mapped_device *md);
434 int dm_wait_event(struct mapped_device *md, int event_nr);
435 uint32_t dm_next_uevent_seq(struct mapped_device *md);
436 void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
441 const char *dm_device_name(struct mapped_device *md);
442 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
443 struct gendisk *dm_disk(struct mapped_device *md);
444 int dm_suspended(struct dm_target *ti);
445 int dm_noflush_suspending(struct dm_target *ti);
446 void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
447 union map_info *dm_get_rq_mapinfo(struct request *rq);
449 struct queue_limits *dm_get_queue_limits(struct mapped_device *md);
452 * Geometry functions.
454 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
455 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
457 /*-----------------------------------------------------------------
458 * Functions for manipulating device-mapper tables.
459 *---------------------------------------------------------------*/
462 * First create an empty table.
464 int dm_table_create(struct dm_table **result, fmode_t mode,
465 unsigned num_targets, struct mapped_device *md);
468 * Then call this once for each target.
470 int dm_table_add_target(struct dm_table *t, const char *type,
471 sector_t start, sector_t len, char *params);
474 * Target_ctr should call this if it needs to add any callbacks.
476 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
479 * Target can use this to set the table's type.
480 * Can only ever be called from a target's ctr.
481 * Useful for "hybrid" target (supports both bio-based
482 * and request-based).
484 void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type);
487 * Finally call this to make the table ready for use.
489 int dm_table_complete(struct dm_table *t);
492 * Target may require that it is never sent I/O larger than len.
494 int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
497 * Table reference counting.
499 struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
500 void dm_put_live_table(struct mapped_device *md, int srcu_idx);
501 void dm_sync_table(struct mapped_device *md);
506 sector_t dm_table_get_size(struct dm_table *t);
507 unsigned int dm_table_get_num_targets(struct dm_table *t);
508 fmode_t dm_table_get_mode(struct dm_table *t);
509 struct mapped_device *dm_table_get_md(struct dm_table *t);
514 void dm_table_event(struct dm_table *t);
517 * Run the queue for request-based targets.
519 void dm_table_run_md_queue_async(struct dm_table *t);
522 * The device must be suspended before calling this method.
523 * Returns the previous table, which the caller must destroy.
525 struct dm_table *dm_swap_table(struct mapped_device *md,
529 * A wrapper around vmalloc.
531 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
533 /*-----------------------------------------------------------------
535 *---------------------------------------------------------------*/
536 #define DM_NAME "device-mapper"
539 extern struct ratelimit_state dm_ratelimit_state;
541 #define dm_ratelimit() __ratelimit(&dm_ratelimit_state)
543 #define dm_ratelimit() 0
546 #define DMCRIT(f, arg...) \
547 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
549 #define DMERR(f, arg...) \
550 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
551 #define DMERR_LIMIT(f, arg...) \
553 if (dm_ratelimit()) \
554 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
558 #define DMWARN(f, arg...) \
559 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
560 #define DMWARN_LIMIT(f, arg...) \
562 if (dm_ratelimit()) \
563 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
567 #define DMINFO(f, arg...) \
568 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
569 #define DMINFO_LIMIT(f, arg...) \
571 if (dm_ratelimit()) \
572 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
576 #ifdef CONFIG_DM_DEBUG
577 # define DMDEBUG(f, arg...) \
578 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
579 # define DMDEBUG_LIMIT(f, arg...) \
581 if (dm_ratelimit()) \
582 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
586 # define DMDEBUG(f, arg...) do {} while (0)
587 # define DMDEBUG_LIMIT(f, arg...) do {} while (0)
590 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
591 0 : scnprintf(result + sz, maxlen - sz, x))
593 #define SECTOR_SHIFT 9
596 * Definitions of return values from target end_io function.
598 #define DM_ENDIO_DONE 0
599 #define DM_ENDIO_INCOMPLETE 1
600 #define DM_ENDIO_REQUEUE 2
603 * Definitions of return values from target map function.
605 #define DM_MAPIO_SUBMITTED 0
606 #define DM_MAPIO_REMAPPED 1
607 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
608 #define DM_MAPIO_DELAY_REQUEUE 3
609 #define DM_MAPIO_KILL 4
611 #define dm_sector_div64(x, y)( \
614 (x) = div64_u64_rem(x, y, &_res); \
622 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
624 #define dm_sector_div_up(n, sz) ( \
626 sector_t _r = ((n) + (sz) - 1); \
627 sector_div(_r, (sz)); \
633 * ceiling(n / size) * size
635 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
637 #define dm_array_too_big(fixed, obj, num) \
638 ((num) > (UINT_MAX - (fixed)) / (obj))
641 * Sector offset taken relative to the start of the target instead of
642 * relative to the start of the device.
644 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
646 static inline sector_t to_sector(unsigned long n)
648 return (n >> SECTOR_SHIFT);
651 static inline unsigned long to_bytes(sector_t n)
653 return (n << SECTOR_SHIFT);
656 #endif /* _LINUX_DEVICE_MAPPER_H */