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_direct_access_fn) (struct dm_target *ti, sector_t sector,
134 void **kaddr, pfn_t *pfn, long size);
136 void dm_error(const char *message);
139 struct block_device *bdev;
144 dev_t dm_get_dev_t(const char *path);
147 * Constructors should call these functions to ensure destination devices
148 * are opened/closed correctly.
150 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
151 struct dm_dev **result);
152 void dm_put_device(struct dm_target *ti, struct dm_dev *d);
155 * Information about a target type
161 struct module *module;
166 dm_clone_and_map_request_fn clone_and_map_rq;
167 dm_release_clone_request_fn release_clone_rq;
169 dm_request_endio_fn rq_end_io;
170 dm_presuspend_fn presuspend;
171 dm_presuspend_undo_fn presuspend_undo;
172 dm_postsuspend_fn postsuspend;
173 dm_preresume_fn preresume;
176 dm_message_fn message;
177 dm_prepare_ioctl_fn prepare_ioctl;
179 dm_iterate_devices_fn iterate_devices;
180 dm_io_hints_fn io_hints;
181 dm_direct_access_fn direct_access;
183 /* For internal device-mapper use. */
184 struct list_head list;
192 * Any table that contains an instance of this target must have only one.
194 #define DM_TARGET_SINGLETON 0x00000001
195 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
198 * Indicates that a target does not support read-only devices.
200 #define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
201 #define dm_target_always_writeable(type) \
202 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
205 * Any device that contains a table with an instance of this target may never
206 * have tables containing any different target type.
208 #define DM_TARGET_IMMUTABLE 0x00000004
209 #define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
212 * Indicates that a target may replace any target; even immutable targets.
213 * .map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined.
215 #define DM_TARGET_WILDCARD 0x00000008
216 #define dm_target_is_wildcard(type) ((type)->features & DM_TARGET_WILDCARD)
219 * Some targets need to be sent the same WRITE bio severals times so
220 * that they can send copies of it to different devices. This function
221 * examines any supplied bio and returns the number of copies of it the
224 typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio *bio);
227 * A target implements own bio data integrity.
229 #define DM_TARGET_INTEGRITY 0x00000010
230 #define dm_target_has_integrity(type) ((type)->features & DM_TARGET_INTEGRITY)
233 * A target passes integrity data to the lower device.
235 #define DM_TARGET_PASSES_INTEGRITY 0x00000020
236 #define dm_target_passes_integrity(type) ((type)->features & DM_TARGET_PASSES_INTEGRITY)
239 struct dm_table *table;
240 struct target_type *type;
246 /* If non-zero, maximum size of I/O submitted to a target. */
250 * A number of zero-length barrier bios that will be submitted
251 * to the target for the purpose of flushing cache.
253 * The bio number can be accessed with dm_bio_get_target_bio_nr.
254 * It is a responsibility of the target driver to remap these bios
255 * to the real underlying devices.
257 unsigned num_flush_bios;
260 * The number of discard bios that will be submitted to the target.
261 * The bio number can be accessed with dm_bio_get_target_bio_nr.
263 unsigned num_discard_bios;
266 * The number of WRITE SAME bios that will be submitted to the target.
267 * The bio number can be accessed with dm_bio_get_target_bio_nr.
269 unsigned num_write_same_bios;
272 * The number of WRITE ZEROES bios that will be submitted to the target.
273 * The bio number can be accessed with dm_bio_get_target_bio_nr.
275 unsigned num_write_zeroes_bios;
278 * The minimum number of extra bytes allocated in each io for the
281 unsigned per_io_data_size;
284 * If defined, this function is called to find out how many
285 * duplicate bios should be sent to the target when writing
288 dm_num_write_bios_fn num_write_bios;
290 /* target specific data */
293 /* Used to provide an error string from the ctr */
297 * Set if this target needs to receive flushes regardless of
298 * whether or not its underlying devices have support.
300 bool flush_supported:1;
303 * Set if this target needs to receive discards regardless of
304 * whether or not its underlying devices have support.
306 bool discards_supported:1;
309 * Set if the target required discard bios to be split
310 * on max_io_len boundary.
312 bool split_discard_bios:1;
315 /* Each target can link one of these into the table */
316 struct dm_target_callbacks {
317 struct list_head list;
318 int (*congested_fn) (struct dm_target_callbacks *, int);
323 * One of these is allocated for each bio.
324 * This structure shouldn't be touched directly by target drivers.
325 * It is here so that we can inline dm_per_bio_data and
326 * dm_bio_from_per_bio_data
328 struct dm_target_io {
330 struct dm_target *ti;
331 unsigned target_bio_nr;
336 static inline void *dm_per_bio_data(struct bio *bio, size_t data_size)
338 return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
341 static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
343 return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
346 static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
348 return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
351 int dm_register_target(struct target_type *t);
352 void dm_unregister_target(struct target_type *t);
355 * Target argument parsing.
363 * The minimum and maximum value of a numeric argument, together with
364 * the error message to use if the number is found to be outside that range.
373 * Validate the next argument, either returning it as *value or, if invalid,
374 * returning -EINVAL and setting *error.
376 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
377 unsigned *value, char **error);
380 * Process the next argument as the start of a group containing between
381 * arg->min and arg->max further arguments. Either return the size as
382 * *num_args or, if invalid, return -EINVAL and set *error.
384 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
385 unsigned *num_args, char **error);
388 * Return the current argument and shift to the next.
390 const char *dm_shift_arg(struct dm_arg_set *as);
393 * Move through num_args arguments.
395 void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
397 /*-----------------------------------------------------------------
398 * Functions for creating and manipulating mapped devices.
399 * Drop the reference with dm_put when you finish with the object.
400 *---------------------------------------------------------------*/
403 * DM_ANY_MINOR chooses the next available minor number.
405 #define DM_ANY_MINOR (-1)
406 int dm_create(int minor, struct mapped_device **md);
409 * Reference counting for md.
411 struct mapped_device *dm_get_md(dev_t dev);
412 void dm_get(struct mapped_device *md);
413 int dm_hold(struct mapped_device *md);
414 void dm_put(struct mapped_device *md);
417 * An arbitrary pointer may be stored alongside a mapped device.
419 void dm_set_mdptr(struct mapped_device *md, void *ptr);
420 void *dm_get_mdptr(struct mapped_device *md);
423 * A device can still be used while suspended, but I/O is deferred.
425 int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
426 int dm_resume(struct mapped_device *md);
431 uint32_t dm_get_event_nr(struct mapped_device *md);
432 int dm_wait_event(struct mapped_device *md, int event_nr);
433 uint32_t dm_next_uevent_seq(struct mapped_device *md);
434 void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
439 const char *dm_device_name(struct mapped_device *md);
440 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
441 struct gendisk *dm_disk(struct mapped_device *md);
442 int dm_suspended(struct dm_target *ti);
443 int dm_noflush_suspending(struct dm_target *ti);
444 void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
445 union map_info *dm_get_rq_mapinfo(struct request *rq);
447 struct queue_limits *dm_get_queue_limits(struct mapped_device *md);
450 * Geometry functions.
452 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
453 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
455 /*-----------------------------------------------------------------
456 * Functions for manipulating device-mapper tables.
457 *---------------------------------------------------------------*/
460 * First create an empty table.
462 int dm_table_create(struct dm_table **result, fmode_t mode,
463 unsigned num_targets, struct mapped_device *md);
466 * Then call this once for each target.
468 int dm_table_add_target(struct dm_table *t, const char *type,
469 sector_t start, sector_t len, char *params);
472 * Target_ctr should call this if it needs to add any callbacks.
474 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
477 * Target can use this to set the table's type.
478 * Can only ever be called from a target's ctr.
479 * Useful for "hybrid" target (supports both bio-based
480 * and request-based).
482 void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type);
485 * Finally call this to make the table ready for use.
487 int dm_table_complete(struct dm_table *t);
490 * Target may require that it is never sent I/O larger than len.
492 int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
495 * Table reference counting.
497 struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
498 void dm_put_live_table(struct mapped_device *md, int srcu_idx);
499 void dm_sync_table(struct mapped_device *md);
504 sector_t dm_table_get_size(struct dm_table *t);
505 unsigned int dm_table_get_num_targets(struct dm_table *t);
506 fmode_t dm_table_get_mode(struct dm_table *t);
507 struct mapped_device *dm_table_get_md(struct dm_table *t);
512 void dm_table_event(struct dm_table *t);
515 * Run the queue for request-based targets.
517 void dm_table_run_md_queue_async(struct dm_table *t);
520 * The device must be suspended before calling this method.
521 * Returns the previous table, which the caller must destroy.
523 struct dm_table *dm_swap_table(struct mapped_device *md,
527 * A wrapper around vmalloc.
529 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
531 /*-----------------------------------------------------------------
533 *---------------------------------------------------------------*/
534 #define DM_NAME "device-mapper"
537 extern struct ratelimit_state dm_ratelimit_state;
539 #define dm_ratelimit() __ratelimit(&dm_ratelimit_state)
541 #define dm_ratelimit() 0
544 #define DMCRIT(f, arg...) \
545 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
547 #define DMERR(f, arg...) \
548 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
549 #define DMERR_LIMIT(f, arg...) \
551 if (dm_ratelimit()) \
552 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
556 #define DMWARN(f, arg...) \
557 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
558 #define DMWARN_LIMIT(f, arg...) \
560 if (dm_ratelimit()) \
561 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
565 #define DMINFO(f, arg...) \
566 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
567 #define DMINFO_LIMIT(f, arg...) \
569 if (dm_ratelimit()) \
570 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
574 #ifdef CONFIG_DM_DEBUG
575 # define DMDEBUG(f, arg...) \
576 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
577 # define DMDEBUG_LIMIT(f, arg...) \
579 if (dm_ratelimit()) \
580 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
584 # define DMDEBUG(f, arg...) do {} while (0)
585 # define DMDEBUG_LIMIT(f, arg...) do {} while (0)
588 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
589 0 : scnprintf(result + sz, maxlen - sz, x))
591 #define SECTOR_SHIFT 9
594 * Definitions of return values from target end_io function.
596 #define DM_ENDIO_INCOMPLETE 1
597 #define DM_ENDIO_REQUEUE 2
600 * Definitions of return values from target map function.
602 #define DM_MAPIO_SUBMITTED 0
603 #define DM_MAPIO_REMAPPED 1
604 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
605 #define DM_MAPIO_DELAY_REQUEUE 3
607 #define dm_sector_div64(x, y)( \
610 (x) = div64_u64_rem(x, y, &_res); \
618 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
620 #define dm_sector_div_up(n, sz) ( \
622 sector_t _r = ((n) + (sz) - 1); \
623 sector_div(_r, (sz)); \
629 * ceiling(n / size) * size
631 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
633 #define dm_array_too_big(fixed, obj, num) \
634 ((num) > (UINT_MAX - (fixed)) / (obj))
637 * Sector offset taken relative to the start of the target instead of
638 * relative to the start of the device.
640 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
642 static inline sector_t to_sector(unsigned long n)
644 return (n >> SECTOR_SHIFT);
647 static inline unsigned long to_bytes(sector_t n)
649 return (n << SECTOR_SHIFT);
652 #endif /* _LINUX_DEVICE_MAPPER_H */