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>
20 typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
24 unsigned long long ll;
25 unsigned target_request_nr;
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 union map_info *map_context);
50 typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
51 union map_info *map_context);
55 * < 0 : error (currently ignored)
56 * 0 : ended successfully
57 * 1 : for some reason the io has still not completed (eg,
58 * multipath target might want to requeue a failed io).
59 * 2 : The target wants to push back the io
61 typedef int (*dm_endio_fn) (struct dm_target *ti,
62 struct bio *bio, int error,
63 union map_info *map_context);
64 typedef int (*dm_request_endio_fn) (struct dm_target *ti,
65 struct request *clone, int error,
66 union map_info *map_context);
68 typedef void (*dm_flush_fn) (struct dm_target *ti);
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 char *result, unsigned int 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
137 struct module *module;
142 dm_map_request_fn map_rq;
144 dm_request_endio_fn rq_end_io;
146 dm_presuspend_fn presuspend;
147 dm_postsuspend_fn postsuspend;
148 dm_preresume_fn preresume;
151 dm_message_fn message;
155 dm_iterate_devices_fn iterate_devices;
156 dm_io_hints_fn io_hints;
158 /* For internal device-mapper use. */
159 struct list_head list;
163 struct dm_table *table;
164 struct target_type *type;
170 /* Always a power of 2 */
174 * A number of zero-length barrier requests that will be submitted
175 * to the target for the purpose of flushing cache.
177 * The request number will be placed in union map_info->target_request_nr.
178 * It is a responsibility of the target driver to remap these requests
179 * to the real underlying devices.
181 unsigned num_flush_requests;
184 * The number of discard requests that will be submitted to the
185 * target. map_info->request_nr is used just like num_flush_requests.
187 unsigned num_discard_requests;
189 /* target specific data */
192 /* Used to provide an error string from the ctr */
196 * Set if this target needs to receive discards regardless of
197 * whether or not its underlying devices have support.
199 unsigned discards_supported:1;
202 /* Each target can link one of these into the table */
203 struct dm_target_callbacks {
204 struct list_head list;
205 int (*congested_fn) (struct dm_target_callbacks *, int);
208 int dm_register_target(struct target_type *t);
209 void dm_unregister_target(struct target_type *t);
211 /*-----------------------------------------------------------------
212 * Functions for creating and manipulating mapped devices.
213 * Drop the reference with dm_put when you finish with the object.
214 *---------------------------------------------------------------*/
217 * DM_ANY_MINOR chooses the next available minor number.
219 #define DM_ANY_MINOR (-1)
220 int dm_create(int minor, struct mapped_device **md);
223 * Reference counting for md.
225 struct mapped_device *dm_get_md(dev_t dev);
226 void dm_get(struct mapped_device *md);
227 void dm_put(struct mapped_device *md);
230 * An arbitrary pointer may be stored alongside a mapped device.
232 void dm_set_mdptr(struct mapped_device *md, void *ptr);
233 void *dm_get_mdptr(struct mapped_device *md);
236 * A device can still be used while suspended, but I/O is deferred.
238 int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
239 int dm_resume(struct mapped_device *md);
244 uint32_t dm_get_event_nr(struct mapped_device *md);
245 int dm_wait_event(struct mapped_device *md, int event_nr);
246 uint32_t dm_next_uevent_seq(struct mapped_device *md);
247 void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
252 const char *dm_device_name(struct mapped_device *md);
253 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
254 struct gendisk *dm_disk(struct mapped_device *md);
255 int dm_suspended(struct dm_target *ti);
256 int dm_noflush_suspending(struct dm_target *ti);
257 union map_info *dm_get_mapinfo(struct bio *bio);
258 union map_info *dm_get_rq_mapinfo(struct request *rq);
261 * Geometry functions.
263 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
264 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
267 /*-----------------------------------------------------------------
268 * Functions for manipulating device-mapper tables.
269 *---------------------------------------------------------------*/
272 * First create an empty table.
274 int dm_table_create(struct dm_table **result, fmode_t mode,
275 unsigned num_targets, struct mapped_device *md);
278 * Then call this once for each target.
280 int dm_table_add_target(struct dm_table *t, const char *type,
281 sector_t start, sector_t len, char *params);
284 * Target_ctr should call this if it needs to add any callbacks.
286 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
289 * Finally call this to make the table ready for use.
291 int dm_table_complete(struct dm_table *t);
294 * Table reference counting.
296 struct dm_table *dm_get_live_table(struct mapped_device *md);
297 void dm_table_get(struct dm_table *t);
298 void dm_table_put(struct dm_table *t);
303 sector_t dm_table_get_size(struct dm_table *t);
304 unsigned int dm_table_get_num_targets(struct dm_table *t);
305 fmode_t dm_table_get_mode(struct dm_table *t);
306 struct mapped_device *dm_table_get_md(struct dm_table *t);
311 void dm_table_event(struct dm_table *t);
314 * The device must be suspended before calling this method.
315 * Returns the previous table, which the caller must destroy.
317 struct dm_table *dm_swap_table(struct mapped_device *md,
321 * A wrapper around vmalloc.
323 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
325 /*-----------------------------------------------------------------
327 *---------------------------------------------------------------*/
328 #define DM_NAME "device-mapper"
330 #define DMCRIT(f, arg...) \
331 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
333 #define DMERR(f, arg...) \
334 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
335 #define DMERR_LIMIT(f, arg...) \
337 if (printk_ratelimit()) \
338 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
342 #define DMWARN(f, arg...) \
343 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
344 #define DMWARN_LIMIT(f, arg...) \
346 if (printk_ratelimit()) \
347 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
351 #define DMINFO(f, arg...) \
352 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
353 #define DMINFO_LIMIT(f, arg...) \
355 if (printk_ratelimit()) \
356 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
360 #ifdef CONFIG_DM_DEBUG
361 # define DMDEBUG(f, arg...) \
362 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
363 # define DMDEBUG_LIMIT(f, arg...) \
365 if (printk_ratelimit()) \
366 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
370 # define DMDEBUG(f, arg...) do {} while (0)
371 # define DMDEBUG_LIMIT(f, arg...) do {} while (0)
374 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
375 0 : scnprintf(result + sz, maxlen - sz, x))
377 #define SECTOR_SHIFT 9
380 * Definitions of return values from target end_io function.
382 #define DM_ENDIO_INCOMPLETE 1
383 #define DM_ENDIO_REQUEUE 2
386 * Definitions of return values from target map function.
388 #define DM_MAPIO_SUBMITTED 0
389 #define DM_MAPIO_REMAPPED 1
390 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
395 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
397 #define dm_sector_div_up(n, sz) ( \
399 sector_t _r = ((n) + (sz) - 1); \
400 sector_div(_r, (sz)); \
406 * ceiling(n / size) * size
408 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
410 #define dm_array_too_big(fixed, obj, num) \
411 ((num) > (UINT_MAX - (fixed)) / (obj))
414 * Sector offset taken relative to the start of the target instead of
415 * relative to the start of the device.
417 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
419 static inline sector_t to_sector(unsigned long n)
421 return (n >> SECTOR_SHIFT);
424 static inline unsigned long to_bytes(sector_t n)
426 return (n << SECTOR_SHIFT);
429 /*-----------------------------------------------------------------
430 * Helper for block layer and dm core operations
431 *---------------------------------------------------------------*/
432 void dm_dispatch_request(struct request *rq);
433 void dm_requeue_unmapped_request(struct request *rq);
434 void dm_kill_unmapped_request(struct request *rq, int error);
435 int dm_underlying_device_busy(struct request_queue *q);
437 #endif /* _LINUX_DEVICE_MAPPER_H */