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
25 #define DM_TYPE_NONE 0
26 #define DM_TYPE_BIO_BASED 1
27 #define DM_TYPE_REQUEST_BASED 2
28 #define DM_TYPE_MQ_REQUEST_BASED 3
29 #define DM_TYPE_DAX_BIO_BASED 4
31 typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
38 * In the constructor the target parameter will already have the
39 * table, type, begin and len fields filled in.
41 typedef int (*dm_ctr_fn) (struct dm_target *target,
42 unsigned int argc, char **argv);
45 * The destructor doesn't need to free the dm_target, just
46 * anything hidden ti->private.
48 typedef void (*dm_dtr_fn) (struct dm_target *ti);
51 * The map function must return:
53 * = 0: The target will handle the io by resubmitting it later
54 * = 1: simple remap complete
55 * = 2: The target wants to push back the io
57 typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
58 typedef int (*dm_clone_and_map_request_fn) (struct dm_target *ti,
60 union map_info *map_context,
61 struct request **clone);
62 typedef void (*dm_release_clone_request_fn) (struct request *clone);
66 * < 0 : error (currently ignored)
67 * 0 : ended successfully
68 * 1 : for some reason the io has still not completed (eg,
69 * multipath target might want to requeue a failed io).
70 * 2 : The target wants to push back the io
72 typedef int (*dm_endio_fn) (struct dm_target *ti,
73 struct bio *bio, int error);
74 typedef int (*dm_request_endio_fn) (struct dm_target *ti,
75 struct request *clone, int error,
76 union map_info *map_context);
78 typedef void (*dm_presuspend_fn) (struct dm_target *ti);
79 typedef void (*dm_presuspend_undo_fn) (struct dm_target *ti);
80 typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
81 typedef int (*dm_preresume_fn) (struct dm_target *ti);
82 typedef void (*dm_resume_fn) (struct dm_target *ti);
84 typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
85 unsigned status_flags, char *result, unsigned maxlen);
87 typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
89 typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti,
90 struct block_device **bdev, fmode_t *mode);
93 * These iteration functions are typically used to check (and combine)
94 * properties of underlying devices.
95 * E.g. Does at least one underlying device support flush?
96 * Does any underlying device not support WRITE_SAME?
98 * The callout function is called once for each contiguous section of
99 * an underlying device. State can be maintained in *data.
100 * Return non-zero to stop iterating through any further devices.
102 typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
104 sector_t start, sector_t len,
108 * This function must iterate through each section of device used by the
109 * target until it encounters a non-zero return code, which it then returns.
110 * Returns zero if no callout returned non-zero.
112 typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
113 iterate_devices_callout_fn fn,
116 typedef void (*dm_io_hints_fn) (struct dm_target *ti,
117 struct queue_limits *limits);
121 * 0: The target can handle the next I/O immediately.
122 * 1: The target can't handle the next I/O immediately.
124 typedef int (*dm_busy_fn) (struct dm_target *ti);
129 * >= 0 : the number of bytes accessible at the address
131 typedef long (*dm_direct_access_fn) (struct dm_target *ti, sector_t sector,
132 void **kaddr, pfn_t *pfn, long size);
134 void dm_error(const char *message);
137 struct block_device *bdev;
142 dev_t dm_get_dev_t(const char *path);
145 * Constructors should call these functions to ensure destination devices
146 * are opened/closed correctly.
148 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
149 struct dm_dev **result);
150 void dm_put_device(struct dm_target *ti, struct dm_dev *d);
153 * Information about a target type
159 struct module *module;
164 dm_clone_and_map_request_fn clone_and_map_rq;
165 dm_release_clone_request_fn release_clone_rq;
167 dm_request_endio_fn rq_end_io;
168 dm_presuspend_fn presuspend;
169 dm_presuspend_undo_fn presuspend_undo;
170 dm_postsuspend_fn postsuspend;
171 dm_preresume_fn preresume;
174 dm_message_fn message;
175 dm_prepare_ioctl_fn prepare_ioctl;
177 dm_iterate_devices_fn iterate_devices;
178 dm_io_hints_fn io_hints;
179 dm_direct_access_fn direct_access;
181 /* For internal device-mapper use. */
182 struct list_head list;
190 * Any table that contains an instance of this target must have only one.
192 #define DM_TARGET_SINGLETON 0x00000001
193 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
196 * Indicates that a target does not support read-only devices.
198 #define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
199 #define dm_target_always_writeable(type) \
200 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
203 * Any device that contains a table with an instance of this target may never
204 * have tables containing any different target type.
206 #define DM_TARGET_IMMUTABLE 0x00000004
207 #define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
210 * Indicates that a target may replace any target; even immutable targets.
211 * .map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined.
213 #define DM_TARGET_WILDCARD 0x00000008
214 #define dm_target_is_wildcard(type) ((type)->features & DM_TARGET_WILDCARD)
217 * Some targets need to be sent the same WRITE bio severals times so
218 * that they can send copies of it to different devices. This function
219 * examines any supplied bio and returns the number of copies of it the
222 typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio *bio);
225 struct dm_table *table;
226 struct target_type *type;
232 /* If non-zero, maximum size of I/O submitted to a target. */
236 * A number of zero-length barrier bios that will be submitted
237 * to the target for the purpose of flushing cache.
239 * The bio number can be accessed with dm_bio_get_target_bio_nr.
240 * It is a responsibility of the target driver to remap these bios
241 * to the real underlying devices.
243 unsigned num_flush_bios;
246 * The number of discard bios that will be submitted to the target.
247 * The bio number can be accessed with dm_bio_get_target_bio_nr.
249 unsigned num_discard_bios;
252 * The number of WRITE SAME bios that will be submitted to the target.
253 * The bio number can be accessed with dm_bio_get_target_bio_nr.
255 unsigned num_write_same_bios;
258 * The number of WRITE ZEROES bios that will be submitted to the target.
259 * The bio number can be accessed with dm_bio_get_target_bio_nr.
261 unsigned num_write_zeroes_bios;
264 * The minimum number of extra bytes allocated in each io for the
267 unsigned per_io_data_size;
270 * If defined, this function is called to find out how many
271 * duplicate bios should be sent to the target when writing
274 dm_num_write_bios_fn num_write_bios;
276 /* target specific data */
279 /* Used to provide an error string from the ctr */
283 * Set if this target needs to receive flushes regardless of
284 * whether or not its underlying devices have support.
286 bool flush_supported:1;
289 * Set if this target needs to receive discards regardless of
290 * whether or not its underlying devices have support.
292 bool discards_supported:1;
295 * Set if the target required discard bios to be split
296 * on max_io_len boundary.
298 bool split_discard_bios:1;
301 /* Each target can link one of these into the table */
302 struct dm_target_callbacks {
303 struct list_head list;
304 int (*congested_fn) (struct dm_target_callbacks *, int);
309 * One of these is allocated for each bio.
310 * This structure shouldn't be touched directly by target drivers.
311 * It is here so that we can inline dm_per_bio_data and
312 * dm_bio_from_per_bio_data
314 struct dm_target_io {
316 struct dm_target *ti;
317 unsigned target_bio_nr;
322 static inline void *dm_per_bio_data(struct bio *bio, size_t data_size)
324 return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
327 static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
329 return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
332 static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
334 return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
337 int dm_register_target(struct target_type *t);
338 void dm_unregister_target(struct target_type *t);
341 * Target argument parsing.
349 * The minimum and maximum value of a numeric argument, together with
350 * the error message to use if the number is found to be outside that range.
359 * Validate the next argument, either returning it as *value or, if invalid,
360 * returning -EINVAL and setting *error.
362 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
363 unsigned *value, char **error);
366 * Process the next argument as the start of a group containing between
367 * arg->min and arg->max further arguments. Either return the size as
368 * *num_args or, if invalid, return -EINVAL and set *error.
370 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
371 unsigned *num_args, char **error);
374 * Return the current argument and shift to the next.
376 const char *dm_shift_arg(struct dm_arg_set *as);
379 * Move through num_args arguments.
381 void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
383 /*-----------------------------------------------------------------
384 * Functions for creating and manipulating mapped devices.
385 * Drop the reference with dm_put when you finish with the object.
386 *---------------------------------------------------------------*/
389 * DM_ANY_MINOR chooses the next available minor number.
391 #define DM_ANY_MINOR (-1)
392 int dm_create(int minor, struct mapped_device **md);
395 * Reference counting for md.
397 struct mapped_device *dm_get_md(dev_t dev);
398 void dm_get(struct mapped_device *md);
399 int dm_hold(struct mapped_device *md);
400 void dm_put(struct mapped_device *md);
403 * An arbitrary pointer may be stored alongside a mapped device.
405 void dm_set_mdptr(struct mapped_device *md, void *ptr);
406 void *dm_get_mdptr(struct mapped_device *md);
409 * A device can still be used while suspended, but I/O is deferred.
411 int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
412 int dm_resume(struct mapped_device *md);
417 uint32_t dm_get_event_nr(struct mapped_device *md);
418 int dm_wait_event(struct mapped_device *md, int event_nr);
419 uint32_t dm_next_uevent_seq(struct mapped_device *md);
420 void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
425 const char *dm_device_name(struct mapped_device *md);
426 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
427 struct gendisk *dm_disk(struct mapped_device *md);
428 int dm_suspended(struct dm_target *ti);
429 int dm_noflush_suspending(struct dm_target *ti);
430 void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
431 union map_info *dm_get_rq_mapinfo(struct request *rq);
433 struct queue_limits *dm_get_queue_limits(struct mapped_device *md);
436 * Geometry functions.
438 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
439 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
441 /*-----------------------------------------------------------------
442 * Functions for manipulating device-mapper tables.
443 *---------------------------------------------------------------*/
446 * First create an empty table.
448 int dm_table_create(struct dm_table **result, fmode_t mode,
449 unsigned num_targets, struct mapped_device *md);
452 * Then call this once for each target.
454 int dm_table_add_target(struct dm_table *t, const char *type,
455 sector_t start, sector_t len, char *params);
458 * Target_ctr should call this if it needs to add any callbacks.
460 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
463 * Target can use this to set the table's type.
464 * Can only ever be called from a target's ctr.
465 * Useful for "hybrid" target (supports both bio-based
466 * and request-based).
468 void dm_table_set_type(struct dm_table *t, unsigned type);
471 * Finally call this to make the table ready for use.
473 int dm_table_complete(struct dm_table *t);
476 * Target may require that it is never sent I/O larger than len.
478 int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
481 * Table reference counting.
483 struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
484 void dm_put_live_table(struct mapped_device *md, int srcu_idx);
485 void dm_sync_table(struct mapped_device *md);
490 sector_t dm_table_get_size(struct dm_table *t);
491 unsigned int dm_table_get_num_targets(struct dm_table *t);
492 fmode_t dm_table_get_mode(struct dm_table *t);
493 struct mapped_device *dm_table_get_md(struct dm_table *t);
498 void dm_table_event(struct dm_table *t);
501 * Run the queue for request-based targets.
503 void dm_table_run_md_queue_async(struct dm_table *t);
506 * The device must be suspended before calling this method.
507 * Returns the previous table, which the caller must destroy.
509 struct dm_table *dm_swap_table(struct mapped_device *md,
513 * A wrapper around vmalloc.
515 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
517 /*-----------------------------------------------------------------
519 *---------------------------------------------------------------*/
520 #define DM_NAME "device-mapper"
523 extern struct ratelimit_state dm_ratelimit_state;
525 #define dm_ratelimit() __ratelimit(&dm_ratelimit_state)
527 #define dm_ratelimit() 0
530 #define DMCRIT(f, arg...) \
531 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
533 #define DMERR(f, arg...) \
534 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
535 #define DMERR_LIMIT(f, arg...) \
537 if (dm_ratelimit()) \
538 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
542 #define DMWARN(f, arg...) \
543 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
544 #define DMWARN_LIMIT(f, arg...) \
546 if (dm_ratelimit()) \
547 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
551 #define DMINFO(f, arg...) \
552 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
553 #define DMINFO_LIMIT(f, arg...) \
555 if (dm_ratelimit()) \
556 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
560 #ifdef CONFIG_DM_DEBUG
561 # define DMDEBUG(f, arg...) \
562 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
563 # define DMDEBUG_LIMIT(f, arg...) \
565 if (dm_ratelimit()) \
566 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
570 # define DMDEBUG(f, arg...) do {} while (0)
571 # define DMDEBUG_LIMIT(f, arg...) do {} while (0)
574 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
575 0 : scnprintf(result + sz, maxlen - sz, x))
577 #define SECTOR_SHIFT 9
580 * Definitions of return values from target end_io function.
582 #define DM_ENDIO_INCOMPLETE 1
583 #define DM_ENDIO_REQUEUE 2
586 * Definitions of return values from target map function.
588 #define DM_MAPIO_SUBMITTED 0
589 #define DM_MAPIO_REMAPPED 1
590 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
591 #define DM_MAPIO_DELAY_REQUEUE 3
593 #define dm_sector_div64(x, y)( \
596 (x) = div64_u64_rem(x, y, &_res); \
604 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
606 #define dm_sector_div_up(n, sz) ( \
608 sector_t _r = ((n) + (sz) - 1); \
609 sector_div(_r, (sz)); \
615 * ceiling(n / size) * size
617 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
619 #define dm_array_too_big(fixed, obj, num) \
620 ((num) > (UINT_MAX - (fixed)) / (obj))
623 * Sector offset taken relative to the start of the target instead of
624 * relative to the start of the device.
626 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
628 static inline sector_t to_sector(unsigned long n)
630 return (n >> SECTOR_SHIFT);
633 static inline unsigned long to_bytes(sector_t n)
635 return (n << SECTOR_SHIFT);
638 #endif /* _LINUX_DEVICE_MAPPER_H */