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>
22 typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
29 * In the constructor the target parameter will already have the
30 * table, type, begin and len fields filled in.
32 typedef int (*dm_ctr_fn) (struct dm_target *target,
33 unsigned int argc, char **argv);
36 * The destructor doesn't need to free the dm_target, just
37 * anything hidden ti->private.
39 typedef void (*dm_dtr_fn) (struct dm_target *ti);
42 * The map function must return:
44 * = 0: The target will handle the io by resubmitting it later
45 * = 1: simple remap complete
46 * = 2: The target wants to push back the io
48 typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
49 typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
50 union map_info *map_context);
51 typedef int (*dm_clone_and_map_request_fn) (struct dm_target *ti,
53 union map_info *map_context,
54 struct request **clone);
55 typedef void (*dm_release_clone_request_fn) (struct request *clone);
59 * < 0 : error (currently ignored)
60 * 0 : ended successfully
61 * 1 : for some reason the io has still not completed (eg,
62 * multipath target might want to requeue a failed io).
63 * 2 : The target wants to push back the io
65 typedef int (*dm_endio_fn) (struct dm_target *ti,
66 struct bio *bio, int error);
67 typedef int (*dm_request_endio_fn) (struct dm_target *ti,
68 struct request *clone, int error,
69 union map_info *map_context);
71 typedef void (*dm_presuspend_fn) (struct dm_target *ti);
72 typedef void (*dm_presuspend_undo_fn) (struct dm_target *ti);
73 typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
74 typedef int (*dm_preresume_fn) (struct dm_target *ti);
75 typedef void (*dm_resume_fn) (struct dm_target *ti);
77 typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
78 unsigned status_flags, char *result, unsigned maxlen);
80 typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
82 typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti,
83 struct block_device **bdev, fmode_t *mode);
86 * These iteration functions are typically used to check (and combine)
87 * properties of underlying devices.
88 * E.g. Does at least one underlying device support flush?
89 * Does any underlying device not support WRITE_SAME?
91 * The callout function is called once for each contiguous section of
92 * an underlying device. State can be maintained in *data.
93 * Return non-zero to stop iterating through any further devices.
95 typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
97 sector_t start, sector_t len,
101 * This function must iterate through each section of device used by the
102 * target until it encounters a non-zero return code, which it then returns.
103 * Returns zero if no callout returned non-zero.
105 typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
106 iterate_devices_callout_fn fn,
109 typedef void (*dm_io_hints_fn) (struct dm_target *ti,
110 struct queue_limits *limits);
114 * 0: The target can handle the next I/O immediately.
115 * 1: The target can't handle the next I/O immediately.
117 typedef int (*dm_busy_fn) (struct dm_target *ti);
119 void dm_error(const char *message);
122 struct block_device *bdev;
127 dev_t dm_get_dev_t(const char *path);
130 * Constructors should call these functions to ensure destination devices
131 * are opened/closed correctly.
133 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
134 struct dm_dev **result);
135 void dm_put_device(struct dm_target *ti, struct dm_dev *d);
138 * Information about a target type
144 struct module *module;
149 dm_map_request_fn map_rq;
150 dm_clone_and_map_request_fn clone_and_map_rq;
151 dm_release_clone_request_fn release_clone_rq;
153 dm_request_endio_fn rq_end_io;
154 dm_presuspend_fn presuspend;
155 dm_presuspend_undo_fn presuspend_undo;
156 dm_postsuspend_fn postsuspend;
157 dm_preresume_fn preresume;
160 dm_message_fn message;
161 dm_prepare_ioctl_fn prepare_ioctl;
163 dm_iterate_devices_fn iterate_devices;
164 dm_io_hints_fn io_hints;
166 /* For internal device-mapper use. */
167 struct list_head list;
175 * Any table that contains an instance of this target must have only one.
177 #define DM_TARGET_SINGLETON 0x00000001
178 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
181 * Indicates that a target does not support read-only devices.
183 #define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
184 #define dm_target_always_writeable(type) \
185 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
188 * Any device that contains a table with an instance of this target may never
189 * have tables containing any different target type.
191 #define DM_TARGET_IMMUTABLE 0x00000004
192 #define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
195 * Some targets need to be sent the same WRITE bio severals times so
196 * that they can send copies of it to different devices. This function
197 * examines any supplied bio and returns the number of copies of it the
200 typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio *bio);
203 struct dm_table *table;
204 struct target_type *type;
210 /* If non-zero, maximum size of I/O submitted to a target. */
214 * A number of zero-length barrier bios that will be submitted
215 * to the target for the purpose of flushing cache.
217 * The bio number can be accessed with dm_bio_get_target_bio_nr.
218 * It is a responsibility of the target driver to remap these bios
219 * to the real underlying devices.
221 unsigned num_flush_bios;
224 * The number of discard bios that will be submitted to the target.
225 * The bio number can be accessed with dm_bio_get_target_bio_nr.
227 unsigned num_discard_bios;
230 * The number of WRITE SAME bios that will be submitted to the target.
231 * The bio number can be accessed with dm_bio_get_target_bio_nr.
233 unsigned num_write_same_bios;
236 * The minimum number of extra bytes allocated in each bio for the
237 * target to use. dm_per_bio_data returns the data location.
239 unsigned per_bio_data_size;
242 * If defined, this function is called to find out how many
243 * duplicate bios should be sent to the target when writing
246 dm_num_write_bios_fn num_write_bios;
248 /* target specific data */
251 /* Used to provide an error string from the ctr */
255 * Set if this target needs to receive flushes regardless of
256 * whether or not its underlying devices have support.
258 bool flush_supported:1;
261 * Set if this target needs to receive discards regardless of
262 * whether or not its underlying devices have support.
264 bool discards_supported:1;
267 * Set if the target required discard bios to be split
268 * on max_io_len boundary.
270 bool split_discard_bios:1;
273 * Set if this target does not return zeroes on discarded blocks.
275 bool discard_zeroes_data_unsupported:1;
278 /* Each target can link one of these into the table */
279 struct dm_target_callbacks {
280 struct list_head list;
281 int (*congested_fn) (struct dm_target_callbacks *, int);
286 * One of these is allocated for each bio.
287 * This structure shouldn't be touched directly by target drivers.
288 * It is here so that we can inline dm_per_bio_data and
289 * dm_bio_from_per_bio_data
291 struct dm_target_io {
293 struct dm_target *ti;
294 unsigned target_bio_nr;
299 static inline void *dm_per_bio_data(struct bio *bio, size_t data_size)
301 return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
304 static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
306 return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
309 static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
311 return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
314 int dm_register_target(struct target_type *t);
315 void dm_unregister_target(struct target_type *t);
318 * Target argument parsing.
326 * The minimum and maximum value of a numeric argument, together with
327 * the error message to use if the number is found to be outside that range.
336 * Validate the next argument, either returning it as *value or, if invalid,
337 * returning -EINVAL and setting *error.
339 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
340 unsigned *value, char **error);
343 * Process the next argument as the start of a group containing between
344 * arg->min and arg->max further arguments. Either return the size as
345 * *num_args or, if invalid, return -EINVAL and set *error.
347 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
348 unsigned *num_args, char **error);
351 * Return the current argument and shift to the next.
353 const char *dm_shift_arg(struct dm_arg_set *as);
356 * Move through num_args arguments.
358 void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
360 /*-----------------------------------------------------------------
361 * Functions for creating and manipulating mapped devices.
362 * Drop the reference with dm_put when you finish with the object.
363 *---------------------------------------------------------------*/
366 * DM_ANY_MINOR chooses the next available minor number.
368 #define DM_ANY_MINOR (-1)
369 int dm_create(int minor, struct mapped_device **md);
372 * Reference counting for md.
374 struct mapped_device *dm_get_md(dev_t dev);
375 void dm_get(struct mapped_device *md);
376 int dm_hold(struct mapped_device *md);
377 void dm_put(struct mapped_device *md);
380 * An arbitrary pointer may be stored alongside a mapped device.
382 void dm_set_mdptr(struct mapped_device *md, void *ptr);
383 void *dm_get_mdptr(struct mapped_device *md);
386 * A device can still be used while suspended, but I/O is deferred.
388 int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
389 int dm_resume(struct mapped_device *md);
394 uint32_t dm_get_event_nr(struct mapped_device *md);
395 int dm_wait_event(struct mapped_device *md, int event_nr);
396 uint32_t dm_next_uevent_seq(struct mapped_device *md);
397 void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
402 const char *dm_device_name(struct mapped_device *md);
403 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
404 struct gendisk *dm_disk(struct mapped_device *md);
405 int dm_suspended(struct dm_target *ti);
406 int dm_noflush_suspending(struct dm_target *ti);
407 void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
408 union map_info *dm_get_rq_mapinfo(struct request *rq);
410 struct queue_limits *dm_get_queue_limits(struct mapped_device *md);
413 * Geometry functions.
415 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
416 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
418 /*-----------------------------------------------------------------
419 * Functions for manipulating device-mapper tables.
420 *---------------------------------------------------------------*/
423 * First create an empty table.
425 int dm_table_create(struct dm_table **result, fmode_t mode,
426 unsigned num_targets, struct mapped_device *md);
429 * Then call this once for each target.
431 int dm_table_add_target(struct dm_table *t, const char *type,
432 sector_t start, sector_t len, char *params);
435 * Target_ctr should call this if it needs to add any callbacks.
437 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
440 * Finally call this to make the table ready for use.
442 int dm_table_complete(struct dm_table *t);
445 * Target may require that it is never sent I/O larger than len.
447 int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
450 * Table reference counting.
452 struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
453 void dm_put_live_table(struct mapped_device *md, int srcu_idx);
454 void dm_sync_table(struct mapped_device *md);
459 sector_t dm_table_get_size(struct dm_table *t);
460 unsigned int dm_table_get_num_targets(struct dm_table *t);
461 fmode_t dm_table_get_mode(struct dm_table *t);
462 struct mapped_device *dm_table_get_md(struct dm_table *t);
467 void dm_table_event(struct dm_table *t);
470 * Run the queue for request-based targets.
472 void dm_table_run_md_queue_async(struct dm_table *t);
475 * The device must be suspended before calling this method.
476 * Returns the previous table, which the caller must destroy.
478 struct dm_table *dm_swap_table(struct mapped_device *md,
482 * A wrapper around vmalloc.
484 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
486 /*-----------------------------------------------------------------
488 *---------------------------------------------------------------*/
489 #define DM_NAME "device-mapper"
492 extern struct ratelimit_state dm_ratelimit_state;
494 #define dm_ratelimit() __ratelimit(&dm_ratelimit_state)
496 #define dm_ratelimit() 0
499 #define DMCRIT(f, arg...) \
500 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
502 #define DMERR(f, arg...) \
503 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
504 #define DMERR_LIMIT(f, arg...) \
506 if (dm_ratelimit()) \
507 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
511 #define DMWARN(f, arg...) \
512 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
513 #define DMWARN_LIMIT(f, arg...) \
515 if (dm_ratelimit()) \
516 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
520 #define DMINFO(f, arg...) \
521 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
522 #define DMINFO_LIMIT(f, arg...) \
524 if (dm_ratelimit()) \
525 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
529 #ifdef CONFIG_DM_DEBUG
530 # define DMDEBUG(f, arg...) \
531 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
532 # define DMDEBUG_LIMIT(f, arg...) \
534 if (dm_ratelimit()) \
535 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
539 # define DMDEBUG(f, arg...) do {} while (0)
540 # define DMDEBUG_LIMIT(f, arg...) do {} while (0)
543 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
544 0 : scnprintf(result + sz, maxlen - sz, x))
546 #define SECTOR_SHIFT 9
549 * Definitions of return values from target end_io function.
551 #define DM_ENDIO_INCOMPLETE 1
552 #define DM_ENDIO_REQUEUE 2
555 * Definitions of return values from target map function.
557 #define DM_MAPIO_SUBMITTED 0
558 #define DM_MAPIO_REMAPPED 1
559 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
561 #define dm_sector_div64(x, y)( \
564 (x) = div64_u64_rem(x, y, &_res); \
572 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
574 #define dm_sector_div_up(n, sz) ( \
576 sector_t _r = ((n) + (sz) - 1); \
577 sector_div(_r, (sz)); \
583 * ceiling(n / size) * size
585 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
587 #define dm_array_too_big(fixed, obj, num) \
588 ((num) > (UINT_MAX - (fixed)) / (obj))
591 * Sector offset taken relative to the start of the target instead of
592 * relative to the start of the device.
594 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
596 static inline sector_t to_sector(unsigned long n)
598 return (n >> SECTOR_SHIFT);
601 static inline unsigned long to_bytes(sector_t n)
603 return (n << SECTOR_SHIFT);
606 #endif /* _LINUX_DEVICE_MAPPER_H */