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;
128 * Constructors should call these functions to ensure destination devices
129 * are opened/closed correctly.
131 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
132 struct dm_dev **result);
133 void dm_put_device(struct dm_target *ti, struct dm_dev *d);
136 * Information about a target type
142 struct module *module;
147 dm_map_request_fn map_rq;
148 dm_clone_and_map_request_fn clone_and_map_rq;
149 dm_release_clone_request_fn release_clone_rq;
151 dm_request_endio_fn rq_end_io;
152 dm_presuspend_fn presuspend;
153 dm_presuspend_undo_fn presuspend_undo;
154 dm_postsuspend_fn postsuspend;
155 dm_preresume_fn preresume;
158 dm_message_fn message;
159 dm_prepare_ioctl_fn prepare_ioctl;
161 dm_iterate_devices_fn iterate_devices;
162 dm_io_hints_fn io_hints;
164 /* For internal device-mapper use. */
165 struct list_head list;
173 * Any table that contains an instance of this target must have only one.
175 #define DM_TARGET_SINGLETON 0x00000001
176 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
179 * Indicates that a target does not support read-only devices.
181 #define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
182 #define dm_target_always_writeable(type) \
183 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
186 * Any device that contains a table with an instance of this target may never
187 * have tables containing any different target type.
189 #define DM_TARGET_IMMUTABLE 0x00000004
190 #define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
193 * Indicates that a target may replace any target; even immutable targets.
194 * .map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined.
196 #define DM_TARGET_WILDCARD 0x00000008
197 #define dm_target_is_wildcard(type) ((type)->features & DM_TARGET_WILDCARD)
200 * Some targets need to be sent the same WRITE bio severals times so
201 * that they can send copies of it to different devices. This function
202 * examines any supplied bio and returns the number of copies of it the
205 typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio *bio);
208 struct dm_table *table;
209 struct target_type *type;
215 /* If non-zero, maximum size of I/O submitted to a target. */
219 * A number of zero-length barrier bios that will be submitted
220 * to the target for the purpose of flushing cache.
222 * The bio number can be accessed with dm_bio_get_target_bio_nr.
223 * It is a responsibility of the target driver to remap these bios
224 * to the real underlying devices.
226 unsigned num_flush_bios;
229 * The number of discard bios that will be submitted to the target.
230 * The bio number can be accessed with dm_bio_get_target_bio_nr.
232 unsigned num_discard_bios;
235 * The number of WRITE SAME bios that will be submitted to the target.
236 * The bio number can be accessed with dm_bio_get_target_bio_nr.
238 unsigned num_write_same_bios;
241 * The minimum number of extra bytes allocated in each io for the
244 unsigned per_io_data_size;
247 * If defined, this function is called to find out how many
248 * duplicate bios should be sent to the target when writing
251 dm_num_write_bios_fn num_write_bios;
253 /* target specific data */
256 /* Used to provide an error string from the ctr */
260 * Set if this target needs to receive flushes regardless of
261 * whether or not its underlying devices have support.
263 bool flush_supported:1;
266 * Set if this target needs to receive discards regardless of
267 * whether or not its underlying devices have support.
269 bool discards_supported:1;
272 * Set if the target required discard bios to be split
273 * on max_io_len boundary.
275 bool split_discard_bios:1;
278 * Set if this target does not return zeroes on discarded blocks.
280 bool discard_zeroes_data_unsupported:1;
283 /* Each target can link one of these into the table */
284 struct dm_target_callbacks {
285 struct list_head list;
286 int (*congested_fn) (struct dm_target_callbacks *, int);
291 * One of these is allocated for each bio.
292 * This structure shouldn't be touched directly by target drivers.
293 * It is here so that we can inline dm_per_bio_data and
294 * dm_bio_from_per_bio_data
296 struct dm_target_io {
298 struct dm_target *ti;
299 unsigned target_bio_nr;
304 static inline void *dm_per_bio_data(struct bio *bio, size_t data_size)
306 return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
309 static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
311 return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
314 static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
316 return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
319 int dm_register_target(struct target_type *t);
320 void dm_unregister_target(struct target_type *t);
323 * Target argument parsing.
331 * The minimum and maximum value of a numeric argument, together with
332 * the error message to use if the number is found to be outside that range.
341 * Validate the next argument, either returning it as *value or, if invalid,
342 * returning -EINVAL and setting *error.
344 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
345 unsigned *value, char **error);
348 * Process the next argument as the start of a group containing between
349 * arg->min and arg->max further arguments. Either return the size as
350 * *num_args or, if invalid, return -EINVAL and set *error.
352 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
353 unsigned *num_args, char **error);
356 * Return the current argument and shift to the next.
358 const char *dm_shift_arg(struct dm_arg_set *as);
361 * Move through num_args arguments.
363 void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
365 /*-----------------------------------------------------------------
366 * Functions for creating and manipulating mapped devices.
367 * Drop the reference with dm_put when you finish with the object.
368 *---------------------------------------------------------------*/
371 * DM_ANY_MINOR chooses the next available minor number.
373 #define DM_ANY_MINOR (-1)
374 int dm_create(int minor, struct mapped_device **md);
377 * Reference counting for md.
379 struct mapped_device *dm_get_md(dev_t dev);
380 void dm_get(struct mapped_device *md);
381 int dm_hold(struct mapped_device *md);
382 void dm_put(struct mapped_device *md);
385 * An arbitrary pointer may be stored alongside a mapped device.
387 void dm_set_mdptr(struct mapped_device *md, void *ptr);
388 void *dm_get_mdptr(struct mapped_device *md);
391 * A device can still be used while suspended, but I/O is deferred.
393 int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
394 int dm_resume(struct mapped_device *md);
399 uint32_t dm_get_event_nr(struct mapped_device *md);
400 int dm_wait_event(struct mapped_device *md, int event_nr);
401 uint32_t dm_next_uevent_seq(struct mapped_device *md);
402 void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
407 const char *dm_device_name(struct mapped_device *md);
408 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
409 struct gendisk *dm_disk(struct mapped_device *md);
410 int dm_suspended(struct dm_target *ti);
411 int dm_noflush_suspending(struct dm_target *ti);
412 void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
413 union map_info *dm_get_rq_mapinfo(struct request *rq);
415 struct queue_limits *dm_get_queue_limits(struct mapped_device *md);
418 * Geometry functions.
420 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
421 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
423 /*-----------------------------------------------------------------
424 * Functions for manipulating device-mapper tables.
425 *---------------------------------------------------------------*/
428 * First create an empty table.
430 int dm_table_create(struct dm_table **result, fmode_t mode,
431 unsigned num_targets, struct mapped_device *md);
434 * Then call this once for each target.
436 int dm_table_add_target(struct dm_table *t, const char *type,
437 sector_t start, sector_t len, char *params);
440 * Target_ctr should call this if it needs to add any callbacks.
442 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
445 * Finally call this to make the table ready for use.
447 int dm_table_complete(struct dm_table *t);
450 * Target may require that it is never sent I/O larger than len.
452 int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
455 * Table reference counting.
457 struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
458 void dm_put_live_table(struct mapped_device *md, int srcu_idx);
459 void dm_sync_table(struct mapped_device *md);
464 sector_t dm_table_get_size(struct dm_table *t);
465 unsigned int dm_table_get_num_targets(struct dm_table *t);
466 fmode_t dm_table_get_mode(struct dm_table *t);
467 struct mapped_device *dm_table_get_md(struct dm_table *t);
472 void dm_table_event(struct dm_table *t);
475 * Run the queue for request-based targets.
477 void dm_table_run_md_queue_async(struct dm_table *t);
480 * The device must be suspended before calling this method.
481 * Returns the previous table, which the caller must destroy.
483 struct dm_table *dm_swap_table(struct mapped_device *md,
487 * A wrapper around vmalloc.
489 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
491 /*-----------------------------------------------------------------
493 *---------------------------------------------------------------*/
494 #define DM_NAME "device-mapper"
497 extern struct ratelimit_state dm_ratelimit_state;
499 #define dm_ratelimit() __ratelimit(&dm_ratelimit_state)
501 #define dm_ratelimit() 0
504 #define DMCRIT(f, arg...) \
505 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
507 #define DMERR(f, arg...) \
508 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
509 #define DMERR_LIMIT(f, arg...) \
511 if (dm_ratelimit()) \
512 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
516 #define DMWARN(f, arg...) \
517 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
518 #define DMWARN_LIMIT(f, arg...) \
520 if (dm_ratelimit()) \
521 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
525 #define DMINFO(f, arg...) \
526 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
527 #define DMINFO_LIMIT(f, arg...) \
529 if (dm_ratelimit()) \
530 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
534 #ifdef CONFIG_DM_DEBUG
535 # define DMDEBUG(f, arg...) \
536 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
537 # define DMDEBUG_LIMIT(f, arg...) \
539 if (dm_ratelimit()) \
540 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
544 # define DMDEBUG(f, arg...) do {} while (0)
545 # define DMDEBUG_LIMIT(f, arg...) do {} while (0)
548 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
549 0 : scnprintf(result + sz, maxlen - sz, x))
551 #define SECTOR_SHIFT 9
554 * Definitions of return values from target end_io function.
556 #define DM_ENDIO_INCOMPLETE 1
557 #define DM_ENDIO_REQUEUE 2
560 * Definitions of return values from target map function.
562 #define DM_MAPIO_SUBMITTED 0
563 #define DM_MAPIO_REMAPPED 1
564 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
566 #define dm_sector_div64(x, y)( \
569 (x) = div64_u64_rem(x, y, &_res); \
577 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
579 #define dm_sector_div_up(n, sz) ( \
581 sector_t _r = ((n) + (sz) - 1); \
582 sector_div(_r, (sz)); \
588 * ceiling(n / size) * size
590 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
592 #define dm_array_too_big(fixed, obj, num) \
593 ((num) > (UINT_MAX - (fixed)) / (obj))
596 * Sector offset taken relative to the start of the target instead of
597 * relative to the start of the device.
599 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
601 static inline sector_t to_sector(unsigned long n)
603 return (n >> SECTOR_SHIFT);
606 static inline unsigned long to_bytes(sector_t n)
608 return (n << SECTOR_SHIFT);
611 #endif /* _LINUX_DEVICE_MAPPER_H */