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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Copyright (C) 2001 Sistina Software (UK) Limited.
Alasdair G Kergon0da336e2008-04-24 21:43:52 +01003 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 *
5 * This file is released under the LGPL.
6 */
7
8#ifndef _LINUX_DEVICE_MAPPER_H
9#define _LINUX_DEVICE_MAPPER_H
10
Heinz Mauelshagen416cd172008-04-24 21:43:35 +010011#include <linux/bio.h>
Milan Brozf6fccb12008-07-21 12:00:37 +010012#include <linux/blkdev.h>
Heinz Mauelshagen416cd172008-04-24 21:43:35 +010013
Mike Snitzeraf4874e2009-06-22 10:12:33 +010014struct dm_dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -070015struct dm_target;
16struct dm_table;
Alasdair G Kergon17b2f662006-06-26 00:27:33 -070017struct mapped_device;
Milan Brozf6fccb12008-07-21 12:00:37 +010018struct bio_vec;
Linus Torvalds1da177e2005-04-16 15:20:36 -070019
20typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
21
22union map_info {
23 void *ptr;
24 unsigned long long ll;
Mike Snitzer57cba5d2010-08-12 04:14:04 +010025 unsigned target_request_nr;
Linus Torvalds1da177e2005-04-16 15:20:36 -070026};
27
28/*
29 * In the constructor the target parameter will already have the
30 * table, type, begin and len fields filled in.
31 */
32typedef int (*dm_ctr_fn) (struct dm_target *target,
33 unsigned int argc, char **argv);
34
35/*
36 * The destructor doesn't need to free the dm_target, just
37 * anything hidden ti->private.
38 */
39typedef void (*dm_dtr_fn) (struct dm_target *ti);
40
41/*
42 * The map function must return:
43 * < 0: error
44 * = 0: The target will handle the io by resubmitting it later
Kiyoshi Ueda45cbcd72006-12-08 02:41:05 -080045 * = 1: simple remap complete
Kiyoshi Ueda2e93ccc2006-12-08 02:41:09 -080046 * = 2: The target wants to push back the io
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 */
48typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
49 union map_info *map_context);
Kiyoshi Ueda7d763452009-01-06 03:05:07 +000050typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
51 union map_info *map_context);
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53/*
54 * Returns:
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).
Kiyoshi Ueda2e93ccc2006-12-08 02:41:09 -080059 * 2 : The target wants to push back the io
Linus Torvalds1da177e2005-04-16 15:20:36 -070060 */
61typedef int (*dm_endio_fn) (struct dm_target *ti,
62 struct bio *bio, int error,
63 union map_info *map_context);
Kiyoshi Ueda7d763452009-01-06 03:05:07 +000064typedef int (*dm_request_endio_fn) (struct dm_target *ti,
65 struct request *clone, int error,
66 union map_info *map_context);
Linus Torvalds1da177e2005-04-16 15:20:36 -070067
Bryn Reeves999d8162006-10-03 01:15:43 -070068typedef void (*dm_flush_fn) (struct dm_target *ti);
Linus Torvalds1da177e2005-04-16 15:20:36 -070069typedef void (*dm_presuspend_fn) (struct dm_target *ti);
70typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
Milan Broz8757b772006-10-03 01:15:36 -070071typedef int (*dm_preresume_fn) (struct dm_target *ti);
Linus Torvalds1da177e2005-04-16 15:20:36 -070072typedef void (*dm_resume_fn) (struct dm_target *ti);
73
74typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
75 char *result, unsigned int maxlen);
76
77typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
78
Al Viro647b3d02007-08-28 22:15:59 -040079typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
Milan Brozaa129a22006-10-03 01:15:15 -070080 unsigned long arg);
81
Milan Brozf6fccb12008-07-21 12:00:37 +010082typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
83 struct bio_vec *biovec, int max_size);
84
Mike Snitzeraf4874e2009-06-22 10:12:33 +010085typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
86 struct dm_dev *dev,
Mike Snitzer5dea2712009-07-23 20:30:42 +010087 sector_t start, sector_t len,
Mike Snitzeraf4874e2009-06-22 10:12:33 +010088 void *data);
89
90typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
91 iterate_devices_callout_fn fn,
92 void *data);
93
Mike Snitzer40bea432009-09-04 20:40:25 +010094typedef void (*dm_io_hints_fn) (struct dm_target *ti,
95 struct queue_limits *limits);
96
Kiyoshi Ueda7d763452009-01-06 03:05:07 +000097/*
98 * Returns:
99 * 0: The target can handle the next I/O immediately.
100 * 1: The target can't handle the next I/O immediately.
101 */
102typedef int (*dm_busy_fn) (struct dm_target *ti);
103
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104void dm_error(const char *message);
105
106/*
Bryn Reeves3cb40212006-10-03 01:15:42 -0700107 * Combine device limits.
108 */
Mike Snitzer754c5fc2009-06-22 10:12:34 +0100109int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
Mike Snitzer5dea2712009-07-23 20:30:42 +0100110 sector_t start, sector_t len, void *data);
Bryn Reeves3cb40212006-10-03 01:15:42 -0700111
Mikulas Patocka82b15192008-10-10 13:37:09 +0100112struct dm_dev {
113 struct block_device *bdev;
Al Viroaeb5d722008-09-02 15:28:45 -0400114 fmode_t mode;
Mikulas Patocka82b15192008-10-10 13:37:09 +0100115 char name[16];
116};
117
Bryn Reeves3cb40212006-10-03 01:15:42 -0700118/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 * Constructors should call these functions to ensure destination devices
120 * are opened/closed correctly.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 */
Nikanth Karthikesan8215d6e2010-03-06 02:32:27 +0000122int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
123 struct dm_dev **result);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124void dm_put_device(struct dm_target *ti, struct dm_dev *d);
125
126/*
127 * Information about a target type
128 */
Andi Kleenab4c142482009-01-06 03:05:09 +0000129
130/*
131 * Target features
132 */
Andi Kleenab4c142482009-01-06 03:05:09 +0000133
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134struct target_type {
Andi Kleenab4c142482009-01-06 03:05:09 +0000135 uint64_t features;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 const char *name;
137 struct module *module;
Alasdair G Kergon17b2f662006-06-26 00:27:33 -0700138 unsigned version[3];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 dm_ctr_fn ctr;
140 dm_dtr_fn dtr;
141 dm_map_fn map;
Kiyoshi Ueda7d763452009-01-06 03:05:07 +0000142 dm_map_request_fn map_rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 dm_endio_fn end_io;
Kiyoshi Ueda7d763452009-01-06 03:05:07 +0000144 dm_request_endio_fn rq_end_io;
Bryn Reeves999d8162006-10-03 01:15:43 -0700145 dm_flush_fn flush;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 dm_presuspend_fn presuspend;
147 dm_postsuspend_fn postsuspend;
Milan Broz8757b772006-10-03 01:15:36 -0700148 dm_preresume_fn preresume;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 dm_resume_fn resume;
150 dm_status_fn status;
151 dm_message_fn message;
Milan Brozaa129a22006-10-03 01:15:15 -0700152 dm_ioctl_fn ioctl;
Milan Brozf6fccb12008-07-21 12:00:37 +0100153 dm_merge_fn merge;
Kiyoshi Ueda7d763452009-01-06 03:05:07 +0000154 dm_busy_fn busy;
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100155 dm_iterate_devices_fn iterate_devices;
Mike Snitzer40bea432009-09-04 20:40:25 +0100156 dm_io_hints_fn io_hints;
Cheng Renquan45194e42009-04-02 19:55:28 +0100157
158 /* For internal device-mapper use. */
159 struct list_head list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160};
161
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162struct dm_target {
163 struct dm_table *table;
164 struct target_type *type;
165
166 /* target limits */
167 sector_t begin;
168 sector_t len;
169
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 /* Always a power of 2 */
171 sector_t split_io;
172
173 /*
Mikulas Patockaf9ab94c2009-06-22 10:12:20 +0100174 * A number of zero-length barrier requests that will be submitted
175 * to the target for the purpose of flushing cache.
176 *
Mike Snitzer57cba5d2010-08-12 04:14:04 +0100177 * The request number will be placed in union map_info->target_request_nr.
Mikulas Patockaf9ab94c2009-06-22 10:12:20 +0100178 * It is a responsibility of the target driver to remap these requests
179 * to the real underlying devices.
180 */
181 unsigned num_flush_requests;
182
Mike Snitzer5ae89a82010-08-12 04:14:08 +0100183 /*
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.
186 */
187 unsigned num_discard_requests;
188
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 /* target specific data */
190 void *private;
191
192 /* Used to provide an error string from the ctr */
193 char *error;
Mike Snitzer4c259322011-05-29 12:52:55 +0100194
195 /*
196 * Set if this target needs to receive discards regardless of
197 * whether or not its underlying devices have support.
198 */
199 unsigned discards_supported:1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200};
201
NeilBrown9d357b02011-01-13 20:00:01 +0000202/* Each target can link one of these into the table */
203struct dm_target_callbacks {
204 struct list_head list;
205 int (*congested_fn) (struct dm_target_callbacks *, int);
206};
207
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208int dm_register_target(struct target_type *t);
Mikulas Patocka10d3bd02009-01-06 03:04:58 +0000209void dm_unregister_target(struct target_type *t);
Alasdair G Kergon17b2f662006-06-26 00:27:33 -0700210
211/*-----------------------------------------------------------------
212 * Functions for creating and manipulating mapped devices.
213 * Drop the reference with dm_put when you finish with the object.
214 *---------------------------------------------------------------*/
215
216/*
217 * DM_ANY_MINOR chooses the next available minor number.
218 */
219#define DM_ANY_MINOR (-1)
220int dm_create(int minor, struct mapped_device **md);
221
222/*
223 * Reference counting for md.
224 */
225struct mapped_device *dm_get_md(dev_t dev);
226void dm_get(struct mapped_device *md);
227void dm_put(struct mapped_device *md);
228
229/*
230 * An arbitrary pointer may be stored alongside a mapped device.
231 */
232void dm_set_mdptr(struct mapped_device *md, void *ptr);
233void *dm_get_mdptr(struct mapped_device *md);
234
235/*
236 * A device can still be used while suspended, but I/O is deferred.
237 */
Kiyoshi Uedaa3d77d32006-12-08 02:41:04 -0800238int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
Alasdair G Kergon17b2f662006-06-26 00:27:33 -0700239int dm_resume(struct mapped_device *md);
240
241/*
242 * Event functions.
243 */
244uint32_t dm_get_event_nr(struct mapped_device *md);
245int dm_wait_event(struct mapped_device *md, int event_nr);
Mike Anderson7a8c3d32007-10-19 22:48:01 +0100246uint32_t dm_next_uevent_seq(struct mapped_device *md);
247void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
Alasdair G Kergon17b2f662006-06-26 00:27:33 -0700248
249/*
250 * Info functions.
251 */
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700252const char *dm_device_name(struct mapped_device *md);
Mike Anderson96a1f7d2007-10-19 22:47:59 +0100253int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
Alasdair G Kergon17b2f662006-06-26 00:27:33 -0700254struct gendisk *dm_disk(struct mapped_device *md);
Kiyoshi Ueda64dbce52009-12-10 23:52:27 +0000255int dm_suspended(struct dm_target *ti);
Kiyoshi Ueda2e93ccc2006-12-08 02:41:09 -0800256int dm_noflush_suspending(struct dm_target *ti);
Mikulas Patocka89343da2008-10-10 13:37:10 +0100257union map_info *dm_get_mapinfo(struct bio *bio);
Kiyoshi Uedacec47e32009-06-22 10:12:35 +0100258union map_info *dm_get_rq_mapinfo(struct request *rq);
Alasdair G Kergon17b2f662006-06-26 00:27:33 -0700259
260/*
261 * Geometry functions.
262 */
263int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
264int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
265
266
267/*-----------------------------------------------------------------
268 * Functions for manipulating device-mapper tables.
269 *---------------------------------------------------------------*/
270
271/*
272 * First create an empty table.
273 */
Al Viroaeb5d722008-09-02 15:28:45 -0400274int dm_table_create(struct dm_table **result, fmode_t mode,
Alasdair G Kergon17b2f662006-06-26 00:27:33 -0700275 unsigned num_targets, struct mapped_device *md);
276
277/*
278 * Then call this once for each target.
279 */
280int dm_table_add_target(struct dm_table *t, const char *type,
281 sector_t start, sector_t len, char *params);
282
283/*
NeilBrown9d357b02011-01-13 20:00:01 +0000284 * Target_ctr should call this if it needs to add any callbacks.
285 */
286void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
287
288/*
Alasdair G Kergon17b2f662006-06-26 00:27:33 -0700289 * Finally call this to make the table ready for use.
290 */
291int dm_table_complete(struct dm_table *t);
292
293/*
294 * Table reference counting.
295 */
Alasdair G Kergon7c666412009-12-10 23:52:19 +0000296struct dm_table *dm_get_live_table(struct mapped_device *md);
Alasdair G Kergon17b2f662006-06-26 00:27:33 -0700297void dm_table_get(struct dm_table *t);
298void dm_table_put(struct dm_table *t);
299
300/*
301 * Queries
302 */
303sector_t dm_table_get_size(struct dm_table *t);
304unsigned int dm_table_get_num_targets(struct dm_table *t);
Al Viroaeb5d722008-09-02 15:28:45 -0400305fmode_t dm_table_get_mode(struct dm_table *t);
Alasdair G Kergon17b2f662006-06-26 00:27:33 -0700306struct mapped_device *dm_table_get_md(struct dm_table *t);
307
308/*
309 * Trigger an event.
310 */
311void dm_table_event(struct dm_table *t);
312
313/*
314 * The device must be suspended before calling this method.
Alasdair G Kergon042d2a92009-12-10 23:52:24 +0000315 * Returns the previous table, which the caller must destroy.
Alasdair G Kergon17b2f662006-06-26 00:27:33 -0700316 */
Alasdair G Kergon042d2a92009-12-10 23:52:24 +0000317struct dm_table *dm_swap_table(struct mapped_device *md,
318 struct dm_table *t);
Alasdair G Kergon17b2f662006-06-26 00:27:33 -0700319
Mikulas Patocka54160902008-10-10 13:37:12 +0100320/*
321 * A wrapper around vmalloc.
322 */
323void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
324
Alasdair G Kergon0da336e2008-04-24 21:43:52 +0100325/*-----------------------------------------------------------------
326 * Macros.
327 *---------------------------------------------------------------*/
328#define DM_NAME "device-mapper"
329
Mikulas Patocka10d3bd02009-01-06 03:04:58 +0000330#define DMCRIT(f, arg...) \
331 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
332
Alasdair G Kergon0da336e2008-04-24 21:43:52 +0100333#define DMERR(f, arg...) \
334 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
335#define DMERR_LIMIT(f, arg...) \
336 do { \
337 if (printk_ratelimit()) \
338 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
339 f "\n", ## arg); \
340 } while (0)
341
342#define DMWARN(f, arg...) \
343 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
344#define DMWARN_LIMIT(f, arg...) \
345 do { \
346 if (printk_ratelimit()) \
347 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
348 f "\n", ## arg); \
349 } while (0)
350
351#define DMINFO(f, arg...) \
352 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
353#define DMINFO_LIMIT(f, arg...) \
354 do { \
355 if (printk_ratelimit()) \
356 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
357 "\n", ## arg); \
358 } while (0)
359
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...) \
364 do { \
365 if (printk_ratelimit()) \
366 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
367 "\n", ## arg); \
368 } while (0)
369#else
370# define DMDEBUG(f, arg...) do {} while (0)
371# define DMDEBUG_LIMIT(f, arg...) do {} while (0)
372#endif
373
374#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
375 0 : scnprintf(result + sz, maxlen - sz, x))
376
377#define SECTOR_SHIFT 9
378
379/*
380 * Definitions of return values from target end_io function.
381 */
382#define DM_ENDIO_INCOMPLETE 1
383#define DM_ENDIO_REQUEUE 2
384
385/*
386 * Definitions of return values from target map function.
387 */
388#define DM_MAPIO_SUBMITTED 0
389#define DM_MAPIO_REMAPPED 1
390#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
391
392/*
393 * Ceiling(n / sz)
394 */
395#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
396
397#define dm_sector_div_up(n, sz) ( \
398{ \
399 sector_t _r = ((n) + (sz) - 1); \
400 sector_div(_r, (sz)); \
401 _r; \
402} \
403)
404
405/*
406 * ceiling(n / size) * size
407 */
408#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
409
Mikulas Patockad63a5ce2008-10-21 17:44:57 +0100410#define dm_array_too_big(fixed, obj, num) \
411 ((num) > (UINT_MAX - (fixed)) / (obj))
412
Mike Snitzer56a67df2010-08-12 04:14:10 +0100413/*
414 * Sector offset taken relative to the start of the target instead of
415 * relative to the start of the device.
416 */
417#define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
418
Alasdair G Kergon0da336e2008-04-24 21:43:52 +0100419static inline sector_t to_sector(unsigned long n)
420{
421 return (n >> SECTOR_SHIFT);
422}
423
424static inline unsigned long to_bytes(sector_t n)
425{
426 return (n << SECTOR_SHIFT);
427}
428
Kiyoshi Uedacec47e32009-06-22 10:12:35 +0100429/*-----------------------------------------------------------------
430 * Helper for block layer and dm core operations
431 *---------------------------------------------------------------*/
432void dm_dispatch_request(struct request *rq);
433void dm_requeue_unmapped_request(struct request *rq);
434void dm_kill_unmapped_request(struct request *rq, int error);
435int dm_underlying_device_busy(struct request_queue *q);
436
Alasdair G Kergon17b2f662006-06-26 00:27:33 -0700437#endif /* _LINUX_DEVICE_MAPPER_H */