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1da177e4
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1/*
2 * Copyright (C) 2001 Sistina Software (UK) Limited.
0da336e5 3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
1da177e4
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4 *
5 * This file is released under the LGPL.
6 */
7
8#ifndef _LINUX_DEVICE_MAPPER_H
9#define _LINUX_DEVICE_MAPPER_H
10
416cd17b 11#include <linux/bio.h>
f6fccb12 12#include <linux/blkdev.h>
416cd17b 13
af4874e0 14struct dm_dev;
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15struct dm_target;
16struct dm_table;
17b2f66f 17struct mapped_device;
f6fccb12 18struct bio_vec;
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19
20typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
21
22union map_info {
23 void *ptr;
24 unsigned long long ll;
57cba5d3 25 unsigned target_request_nr;
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26};
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
45cbcd79 45 * = 1: simple remap complete
2e93ccc1 46 * = 2: The target wants to push back the io
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47 */
48typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
49 union map_info *map_context);
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50typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
51 union map_info *map_context);
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52
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).
2e93ccc1 59 * 2 : The target wants to push back the io
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60 */
61typedef int (*dm_endio_fn) (struct dm_target *ti,
62 struct bio *bio, int error,
63 union map_info *map_context);
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64typedef int (*dm_request_endio_fn) (struct dm_target *ti,
65 struct request *clone, int error,
66 union map_info *map_context);
1da177e4 67
999d8168 68typedef void (*dm_flush_fn) (struct dm_target *ti);
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69typedef void (*dm_presuspend_fn) (struct dm_target *ti);
70typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
8757b776 71typedef int (*dm_preresume_fn) (struct dm_target *ti);
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72typedef 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
647b3d00 79typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
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80 unsigned long arg);
81
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82typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
83 struct bio_vec *biovec, int max_size);
84
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85typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
86 struct dm_dev *dev,
5dea271b 87 sector_t start, sector_t len,
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88 void *data);
89
90typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
91 iterate_devices_callout_fn fn,
92 void *data);
93
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94typedef void (*dm_io_hints_fn) (struct dm_target *ti,
95 struct queue_limits *limits);
96
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97/*
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
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104void dm_error(const char *message);
105
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106/*
107 * Combine device limits.
108 */
754c5fc7 109int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
5dea271b 110 sector_t start, sector_t len, void *data);
3cb40214 111
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112struct dm_dev {
113 struct block_device *bdev;
aeb5d727 114 fmode_t mode;
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115 char name[16];
116};
117
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118/*
119 * Constructors should call these functions to ensure destination devices
120 * are opened/closed correctly.
1da177e4 121 */
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122int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
123 struct dm_dev **result);
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124void dm_put_device(struct dm_target *ti, struct dm_dev *d);
125
126/*
127 * Information about a target type
128 */
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129
130/*
131 * Target features
132 */
ab4c1424 133
1da177e4 134struct target_type {
ab4c1424 135 uint64_t features;
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136 const char *name;
137 struct module *module;
17b2f66f 138 unsigned version[3];
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139 dm_ctr_fn ctr;
140 dm_dtr_fn dtr;
141 dm_map_fn map;
7d76345d 142 dm_map_request_fn map_rq;
1da177e4 143 dm_endio_fn end_io;
7d76345d 144 dm_request_endio_fn rq_end_io;
999d8168 145 dm_flush_fn flush;
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146 dm_presuspend_fn presuspend;
147 dm_postsuspend_fn postsuspend;
8757b776 148 dm_preresume_fn preresume;
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149 dm_resume_fn resume;
150 dm_status_fn status;
151 dm_message_fn message;
aa129a22 152 dm_ioctl_fn ioctl;
f6fccb12 153 dm_merge_fn merge;
7d76345d 154 dm_busy_fn busy;
af4874e0 155 dm_iterate_devices_fn iterate_devices;
40bea431 156 dm_io_hints_fn io_hints;
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157
158 /* For internal device-mapper use. */
159 struct list_head list;
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160};
161
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162struct 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
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170 /* Always a power of 2 */
171 sector_t split_io;
172
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173 /*
174 * A number of zero-length barrier requests that will be submitted
175 * to the target for the purpose of flushing cache.
176 *
57cba5d3 177 * The request number will be placed in union map_info->target_request_nr.
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178 * 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
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183 /*
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
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189 /* target specific data */
190 void *private;
191
192 /* Used to provide an error string from the ctr */
193 char *error;
194};
195
196int dm_register_target(struct target_type *t);
10d3bd09 197void dm_unregister_target(struct target_type *t);
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198
199/*-----------------------------------------------------------------
200 * Functions for creating and manipulating mapped devices.
201 * Drop the reference with dm_put when you finish with the object.
202 *---------------------------------------------------------------*/
203
204/*
205 * DM_ANY_MINOR chooses the next available minor number.
206 */
207#define DM_ANY_MINOR (-1)
208int dm_create(int minor, struct mapped_device **md);
209
210/*
211 * Reference counting for md.
212 */
213struct mapped_device *dm_get_md(dev_t dev);
214void dm_get(struct mapped_device *md);
215void dm_put(struct mapped_device *md);
216
217/*
218 * An arbitrary pointer may be stored alongside a mapped device.
219 */
220void dm_set_mdptr(struct mapped_device *md, void *ptr);
221void *dm_get_mdptr(struct mapped_device *md);
222
223/*
224 * A device can still be used while suspended, but I/O is deferred.
225 */
a3d77d35 226int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
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227int dm_resume(struct mapped_device *md);
228
229/*
230 * Event functions.
231 */
232uint32_t dm_get_event_nr(struct mapped_device *md);
233int dm_wait_event(struct mapped_device *md, int event_nr);
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234uint32_t dm_next_uevent_seq(struct mapped_device *md);
235void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
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236
237/*
238 * Info functions.
239 */
72d94861 240const char *dm_device_name(struct mapped_device *md);
96a1f7db 241int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
17b2f66f 242struct gendisk *dm_disk(struct mapped_device *md);
64dbce58 243int dm_suspended(struct dm_target *ti);
2e93ccc1 244int dm_noflush_suspending(struct dm_target *ti);
89343da0 245union map_info *dm_get_mapinfo(struct bio *bio);
cec47e3d 246union map_info *dm_get_rq_mapinfo(struct request *rq);
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247
248/*
249 * Geometry functions.
250 */
251int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
252int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
253
254
255/*-----------------------------------------------------------------
256 * Functions for manipulating device-mapper tables.
257 *---------------------------------------------------------------*/
258
259/*
260 * First create an empty table.
261 */
aeb5d727 262int dm_table_create(struct dm_table **result, fmode_t mode,
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263 unsigned num_targets, struct mapped_device *md);
264
265/*
266 * Then call this once for each target.
267 */
268int dm_table_add_target(struct dm_table *t, const char *type,
269 sector_t start, sector_t len, char *params);
270
271/*
272 * Finally call this to make the table ready for use.
273 */
274int dm_table_complete(struct dm_table *t);
275
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276/*
277 * Unplug all devices in a table.
278 */
279void dm_table_unplug_all(struct dm_table *t);
280
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281/*
282 * Table reference counting.
283 */
7c666411 284struct dm_table *dm_get_live_table(struct mapped_device *md);
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285void dm_table_get(struct dm_table *t);
286void dm_table_put(struct dm_table *t);
287
288/*
289 * Queries
290 */
291sector_t dm_table_get_size(struct dm_table *t);
292unsigned int dm_table_get_num_targets(struct dm_table *t);
aeb5d727 293fmode_t dm_table_get_mode(struct dm_table *t);
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294struct mapped_device *dm_table_get_md(struct dm_table *t);
295
296/*
297 * Trigger an event.
298 */
299void dm_table_event(struct dm_table *t);
300
301/*
302 * The device must be suspended before calling this method.
042d2a9b 303 * Returns the previous table, which the caller must destroy.
17b2f66f 304 */
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305struct dm_table *dm_swap_table(struct mapped_device *md,
306 struct dm_table *t);
17b2f66f 307
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308/*
309 * A wrapper around vmalloc.
310 */
311void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
312
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313/*-----------------------------------------------------------------
314 * Macros.
315 *---------------------------------------------------------------*/
316#define DM_NAME "device-mapper"
317
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318#define DMCRIT(f, arg...) \
319 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
320
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321#define DMERR(f, arg...) \
322 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
323#define DMERR_LIMIT(f, arg...) \
324 do { \
325 if (printk_ratelimit()) \
326 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
327 f "\n", ## arg); \
328 } while (0)
329
330#define DMWARN(f, arg...) \
331 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
332#define DMWARN_LIMIT(f, arg...) \
333 do { \
334 if (printk_ratelimit()) \
335 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
336 f "\n", ## arg); \
337 } while (0)
338
339#define DMINFO(f, arg...) \
340 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
341#define DMINFO_LIMIT(f, arg...) \
342 do { \
343 if (printk_ratelimit()) \
344 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
345 "\n", ## arg); \
346 } while (0)
347
348#ifdef CONFIG_DM_DEBUG
349# define DMDEBUG(f, arg...) \
350 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
351# define DMDEBUG_LIMIT(f, arg...) \
352 do { \
353 if (printk_ratelimit()) \
354 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
355 "\n", ## arg); \
356 } while (0)
357#else
358# define DMDEBUG(f, arg...) do {} while (0)
359# define DMDEBUG_LIMIT(f, arg...) do {} while (0)
360#endif
361
362#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
363 0 : scnprintf(result + sz, maxlen - sz, x))
364
365#define SECTOR_SHIFT 9
366
367/*
368 * Definitions of return values from target end_io function.
369 */
370#define DM_ENDIO_INCOMPLETE 1
371#define DM_ENDIO_REQUEUE 2
372
373/*
374 * Definitions of return values from target map function.
375 */
376#define DM_MAPIO_SUBMITTED 0
377#define DM_MAPIO_REMAPPED 1
378#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
379
380/*
381 * Ceiling(n / sz)
382 */
383#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
384
385#define dm_sector_div_up(n, sz) ( \
386{ \
387 sector_t _r = ((n) + (sz) - 1); \
388 sector_div(_r, (sz)); \
389 _r; \
390} \
391)
392
393/*
394 * ceiling(n / size) * size
395 */
396#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
397
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398#define dm_array_too_big(fixed, obj, num) \
399 ((num) > (UINT_MAX - (fixed)) / (obj))
400
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401static inline sector_t to_sector(unsigned long n)
402{
403 return (n >> SECTOR_SHIFT);
404}
405
406static inline unsigned long to_bytes(sector_t n)
407{
408 return (n << SECTOR_SHIFT);
409}
410
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411/*-----------------------------------------------------------------
412 * Helper for block layer and dm core operations
413 *---------------------------------------------------------------*/
414void dm_dispatch_request(struct request *rq);
415void dm_requeue_unmapped_request(struct request *rq);
416void dm_kill_unmapped_request(struct request *rq, int error);
417int dm_underlying_device_busy(struct request_queue *q);
418
17b2f66f 419#endif /* _LINUX_DEVICE_MAPPER_H */