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/ratelimit.h>
21 typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
25 unsigned long long ll;
26 unsigned target_request_nr;
30 * In the constructor the target parameter will already have the
31 * table, type, begin and len fields filled in.
33 typedef int (*dm_ctr_fn) (struct dm_target *target,
34 unsigned int argc, char **argv);
37 * The destructor doesn't need to free the dm_target, just
38 * anything hidden ti->private.
40 typedef void (*dm_dtr_fn) (struct dm_target *ti);
43 * The map function must return:
45 * = 0: The target will handle the io by resubmitting it later
46 * = 1: simple remap complete
47 * = 2: The target wants to push back the io
49 typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
50 union map_info *map_context);
51 typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
52 union map_info *map_context);
56 * < 0 : error (currently ignored)
57 * 0 : ended successfully
58 * 1 : for some reason the io has still not completed (eg,
59 * multipath target might want to requeue a failed io).
60 * 2 : The target wants to push back the io
62 typedef int (*dm_endio_fn) (struct dm_target *ti,
63 struct bio *bio, int error,
64 union map_info *map_context);
65 typedef int (*dm_request_endio_fn) (struct dm_target *ti,
66 struct request *clone, int error,
67 union map_info *map_context);
69 typedef void (*dm_presuspend_fn) (struct dm_target *ti);
70 typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
71 typedef int (*dm_preresume_fn) (struct dm_target *ti);
72 typedef void (*dm_resume_fn) (struct dm_target *ti);
74 typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
75 unsigned status_flags, char *result, unsigned maxlen);
77 typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
79 typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
82 typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
83 struct bio_vec *biovec, int max_size);
85 typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
87 sector_t start, sector_t len,
90 typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
91 iterate_devices_callout_fn fn,
94 typedef void (*dm_io_hints_fn) (struct dm_target *ti,
95 struct queue_limits *limits);
99 * 0: The target can handle the next I/O immediately.
100 * 1: The target can't handle the next I/O immediately.
102 typedef int (*dm_busy_fn) (struct dm_target *ti);
104 void dm_error(const char *message);
107 * Combine device limits.
109 int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
110 sector_t start, sector_t len, void *data);
113 struct block_device *bdev;
119 * Constructors should call these functions to ensure destination devices
120 * are opened/closed correctly.
122 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
123 struct dm_dev **result);
124 void dm_put_device(struct dm_target *ti, struct dm_dev *d);
127 * Information about a target type
133 struct module *module;
138 dm_map_request_fn map_rq;
140 dm_request_endio_fn rq_end_io;
141 dm_presuspend_fn presuspend;
142 dm_postsuspend_fn postsuspend;
143 dm_preresume_fn preresume;
146 dm_message_fn message;
150 dm_iterate_devices_fn iterate_devices;
151 dm_io_hints_fn io_hints;
153 /* For internal device-mapper use. */
154 struct list_head list;
162 * Any table that contains an instance of this target must have only one.
164 #define DM_TARGET_SINGLETON 0x00000001
165 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
168 * Indicates that a target does not support read-only devices.
170 #define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
171 #define dm_target_always_writeable(type) \
172 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
175 * Any device that contains a table with an instance of this target may never
176 * have tables containing any different target type.
178 #define DM_TARGET_IMMUTABLE 0x00000004
179 #define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
182 struct dm_table *table;
183 struct target_type *type;
189 /* If non-zero, maximum size of I/O submitted to a target. */
193 * A number of zero-length barrier requests that will be submitted
194 * to the target for the purpose of flushing cache.
196 * The request number will be placed in union map_info->target_request_nr.
197 * It is a responsibility of the target driver to remap these requests
198 * to the real underlying devices.
200 unsigned num_flush_requests;
203 * The number of discard requests that will be submitted to the
204 * target. map_info->request_nr is used just like num_flush_requests.
206 unsigned num_discard_requests;
209 * The number of WRITE SAME requests that will be submitted to the target.
211 unsigned num_write_same_requests;
213 /* target specific data */
216 /* Used to provide an error string from the ctr */
220 * Set if this target needs to receive flushes regardless of
221 * whether or not its underlying devices have support.
223 bool flush_supported:1;
226 * Set if this target needs to receive discards regardless of
227 * whether or not its underlying devices have support.
229 bool discards_supported:1;
232 * Set if the target required discard request to be split
233 * on max_io_len boundary.
235 bool split_discard_requests:1;
238 * Set if this target does not return zeroes on discarded blocks.
240 bool discard_zeroes_data_unsupported:1;
243 /* Each target can link one of these into the table */
244 struct dm_target_callbacks {
245 struct list_head list;
246 int (*congested_fn) (struct dm_target_callbacks *, int);
249 int dm_register_target(struct target_type *t);
250 void dm_unregister_target(struct target_type *t);
253 * Target argument parsing.
261 * The minimum and maximum value of a numeric argument, together with
262 * the error message to use if the number is found to be outside that range.
271 * Validate the next argument, either returning it as *value or, if invalid,
272 * returning -EINVAL and setting *error.
274 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
275 unsigned *value, char **error);
278 * Process the next argument as the start of a group containing between
279 * arg->min and arg->max further arguments. Either return the size as
280 * *num_args or, if invalid, return -EINVAL and set *error.
282 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
283 unsigned *num_args, char **error);
286 * Return the current argument and shift to the next.
288 const char *dm_shift_arg(struct dm_arg_set *as);
291 * Move through num_args arguments.
293 void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
295 /*-----------------------------------------------------------------
296 * Functions for creating and manipulating mapped devices.
297 * Drop the reference with dm_put when you finish with the object.
298 *---------------------------------------------------------------*/
301 * DM_ANY_MINOR chooses the next available minor number.
303 #define DM_ANY_MINOR (-1)
304 int dm_create(int minor, struct mapped_device **md);
307 * Reference counting for md.
309 struct mapped_device *dm_get_md(dev_t dev);
310 void dm_get(struct mapped_device *md);
311 void dm_put(struct mapped_device *md);
314 * An arbitrary pointer may be stored alongside a mapped device.
316 void dm_set_mdptr(struct mapped_device *md, void *ptr);
317 void *dm_get_mdptr(struct mapped_device *md);
320 * A device can still be used while suspended, but I/O is deferred.
322 int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
323 int dm_resume(struct mapped_device *md);
328 uint32_t dm_get_event_nr(struct mapped_device *md);
329 int dm_wait_event(struct mapped_device *md, int event_nr);
330 uint32_t dm_next_uevent_seq(struct mapped_device *md);
331 void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
336 const char *dm_device_name(struct mapped_device *md);
337 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
338 struct gendisk *dm_disk(struct mapped_device *md);
339 int dm_suspended(struct dm_target *ti);
340 int dm_noflush_suspending(struct dm_target *ti);
341 union map_info *dm_get_mapinfo(struct bio *bio);
342 union map_info *dm_get_rq_mapinfo(struct request *rq);
345 * Geometry functions.
347 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
348 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
351 /*-----------------------------------------------------------------
352 * Functions for manipulating device-mapper tables.
353 *---------------------------------------------------------------*/
356 * First create an empty table.
358 int dm_table_create(struct dm_table **result, fmode_t mode,
359 unsigned num_targets, struct mapped_device *md);
362 * Then call this once for each target.
364 int dm_table_add_target(struct dm_table *t, const char *type,
365 sector_t start, sector_t len, char *params);
368 * Target_ctr should call this if it needs to add any callbacks.
370 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
373 * Finally call this to make the table ready for use.
375 int dm_table_complete(struct dm_table *t);
378 * Target may require that it is never sent I/O larger than len.
380 int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
383 * Table reference counting.
385 struct dm_table *dm_get_live_table(struct mapped_device *md);
386 void dm_table_get(struct dm_table *t);
387 void dm_table_put(struct dm_table *t);
392 sector_t dm_table_get_size(struct dm_table *t);
393 unsigned int dm_table_get_num_targets(struct dm_table *t);
394 fmode_t dm_table_get_mode(struct dm_table *t);
395 struct mapped_device *dm_table_get_md(struct dm_table *t);
400 void dm_table_event(struct dm_table *t);
403 * The device must be suspended before calling this method.
404 * Returns the previous table, which the caller must destroy.
406 struct dm_table *dm_swap_table(struct mapped_device *md,
410 * A wrapper around vmalloc.
412 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
414 /*-----------------------------------------------------------------
416 *---------------------------------------------------------------*/
417 #define DM_NAME "device-mapper"
420 extern struct ratelimit_state dm_ratelimit_state;
422 #define dm_ratelimit() __ratelimit(&dm_ratelimit_state)
424 #define dm_ratelimit() 0
427 #define DMCRIT(f, arg...) \
428 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
430 #define DMERR(f, arg...) \
431 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
432 #define DMERR_LIMIT(f, arg...) \
434 if (dm_ratelimit()) \
435 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
439 #define DMWARN(f, arg...) \
440 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
441 #define DMWARN_LIMIT(f, arg...) \
443 if (dm_ratelimit()) \
444 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
448 #define DMINFO(f, arg...) \
449 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
450 #define DMINFO_LIMIT(f, arg...) \
452 if (dm_ratelimit()) \
453 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
457 #ifdef CONFIG_DM_DEBUG
458 # define DMDEBUG(f, arg...) \
459 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
460 # define DMDEBUG_LIMIT(f, arg...) \
462 if (dm_ratelimit()) \
463 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
467 # define DMDEBUG(f, arg...) do {} while (0)
468 # define DMDEBUG_LIMIT(f, arg...) do {} while (0)
471 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
472 0 : scnprintf(result + sz, maxlen - sz, x))
474 #define SECTOR_SHIFT 9
477 * Definitions of return values from target end_io function.
479 #define DM_ENDIO_INCOMPLETE 1
480 #define DM_ENDIO_REQUEUE 2
483 * Definitions of return values from target map function.
485 #define DM_MAPIO_SUBMITTED 0
486 #define DM_MAPIO_REMAPPED 1
487 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
492 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
494 #define dm_sector_div_up(n, sz) ( \
496 sector_t _r = ((n) + (sz) - 1); \
497 sector_div(_r, (sz)); \
503 * ceiling(n / size) * size
505 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
507 #define dm_array_too_big(fixed, obj, num) \
508 ((num) > (UINT_MAX - (fixed)) / (obj))
511 * Sector offset taken relative to the start of the target instead of
512 * relative to the start of the device.
514 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
516 static inline sector_t to_sector(unsigned long n)
518 return (n >> SECTOR_SHIFT);
521 static inline unsigned long to_bytes(sector_t n)
523 return (n << SECTOR_SHIFT);
526 /*-----------------------------------------------------------------
527 * Helper for block layer and dm core operations
528 *---------------------------------------------------------------*/
529 void dm_dispatch_request(struct request *rq);
530 void dm_requeue_unmapped_request(struct request *rq);
531 void dm_kill_unmapped_request(struct request *rq, int error);
532 int dm_underlying_device_busy(struct request_queue *q);
534 #endif /* _LINUX_DEVICE_MAPPER_H */