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1/*
2 * Copyright (C) 2001 Sistina Software (UK) Limited.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
4 *
5 * This file is released under the LGPL.
6 */
7
8#ifndef _LINUX_DEVICE_MAPPER_H
9#define _LINUX_DEVICE_MAPPER_H
10
11#include <linux/bio.h>
12#include <linux/blkdev.h>
13
14struct dm_target;
15struct dm_table;
16struct mapped_device;
17struct bio_vec;
18
19typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
20
21union map_info {
22 void *ptr;
23 unsigned long long ll;
24};
25
26/*
27 * In the constructor the target parameter will already have the
28 * table, type, begin and len fields filled in.
29 */
30typedef int (*dm_ctr_fn) (struct dm_target *target,
31 unsigned int argc, char **argv);
32
33/*
34 * The destructor doesn't need to free the dm_target, just
35 * anything hidden ti->private.
36 */
37typedef void (*dm_dtr_fn) (struct dm_target *ti);
38
39/*
40 * The map function must return:
41 * < 0: error
42 * = 0: The target will handle the io by resubmitting it later
43 * = 1: simple remap complete
44 * = 2: The target wants to push back the io
45 */
46typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
47 union map_info *map_context);
48typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
49 union map_info *map_context);
50
51/*
52 * Returns:
53 * < 0 : error (currently ignored)
54 * 0 : ended successfully
55 * 1 : for some reason the io has still not completed (eg,
56 * multipath target might want to requeue a failed io).
57 * 2 : The target wants to push back the io
58 */
59typedef int (*dm_endio_fn) (struct dm_target *ti,
60 struct bio *bio, int error,
61 union map_info *map_context);
62typedef int (*dm_request_endio_fn) (struct dm_target *ti,
63 struct request *clone, int error,
64 union map_info *map_context);
65
66typedef void (*dm_flush_fn) (struct dm_target *ti);
67typedef void (*dm_presuspend_fn) (struct dm_target *ti);
68typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
69typedef int (*dm_preresume_fn) (struct dm_target *ti);
70typedef void (*dm_resume_fn) (struct dm_target *ti);
71
72typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
73 char *result, unsigned int maxlen);
74
75typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
76
77typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
78 unsigned long arg);
79
80typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
81 struct bio_vec *biovec, int max_size);
82
83/*
84 * Returns:
85 * 0: The target can handle the next I/O immediately.
86 * 1: The target can't handle the next I/O immediately.
87 */
88typedef int (*dm_busy_fn) (struct dm_target *ti);
89
90void dm_error(const char *message);
91
92/*
93 * Combine device limits.
94 */
95void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev);
96
97struct dm_dev {
98 struct block_device *bdev;
99 fmode_t mode;
100 char name[16];
101};
102
103/*
104 * Constructors should call these functions to ensure destination devices
105 * are opened/closed correctly.
106 * FIXME: too many arguments.
107 */
108int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
109 sector_t len, fmode_t mode, struct dm_dev **result);
110void dm_put_device(struct dm_target *ti, struct dm_dev *d);
111
112/*
113 * Information about a target type
114 */
115
116/*
117 * Target features
118 */
119#define DM_TARGET_SUPPORTS_BARRIERS 0x00000001
120
121struct target_type {
122 uint64_t features;
123 const char *name;
124 struct module *module;
125 unsigned version[3];
126 dm_ctr_fn ctr;
127 dm_dtr_fn dtr;
128 dm_map_fn map;
129 dm_map_request_fn map_rq;
130 dm_endio_fn end_io;
131 dm_request_endio_fn rq_end_io;
132 dm_flush_fn flush;
133 dm_presuspend_fn presuspend;
134 dm_postsuspend_fn postsuspend;
135 dm_preresume_fn preresume;
136 dm_resume_fn resume;
137 dm_status_fn status;
138 dm_message_fn message;
139 dm_ioctl_fn ioctl;
140 dm_merge_fn merge;
141 dm_busy_fn busy;
142};
143
144struct io_restrictions {
145 unsigned long bounce_pfn;
146 unsigned long seg_boundary_mask;
147 unsigned max_hw_sectors;
148 unsigned max_sectors;
149 unsigned max_segment_size;
150 unsigned short hardsect_size;
151 unsigned short max_hw_segments;
152 unsigned short max_phys_segments;
153 unsigned char no_cluster; /* inverted so that 0 is default */
154};
155
156struct dm_target {
157 struct dm_table *table;
158 struct target_type *type;
159
160 /* target limits */
161 sector_t begin;
162 sector_t len;
163
164 /* FIXME: turn this into a mask, and merge with io_restrictions */
165 /* Always a power of 2 */
166 sector_t split_io;
167
168 /*
169 * These are automatically filled in by
170 * dm_table_get_device.
171 */
172 struct io_restrictions limits;
173
174 /* target specific data */
175 void *private;
176
177 /* Used to provide an error string from the ctr */
178 char *error;
179};
180
181int dm_register_target(struct target_type *t);
182void dm_unregister_target(struct target_type *t);
183
184/*-----------------------------------------------------------------
185 * Functions for creating and manipulating mapped devices.
186 * Drop the reference with dm_put when you finish with the object.
187 *---------------------------------------------------------------*/
188
189/*
190 * DM_ANY_MINOR chooses the next available minor number.
191 */
192#define DM_ANY_MINOR (-1)
193int dm_create(int minor, struct mapped_device **md);
194
195/*
196 * Reference counting for md.
197 */
198struct mapped_device *dm_get_md(dev_t dev);
199void dm_get(struct mapped_device *md);
200void dm_put(struct mapped_device *md);
201
202/*
203 * An arbitrary pointer may be stored alongside a mapped device.
204 */
205void dm_set_mdptr(struct mapped_device *md, void *ptr);
206void *dm_get_mdptr(struct mapped_device *md);
207
208/*
209 * A device can still be used while suspended, but I/O is deferred.
210 */
211int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
212int dm_resume(struct mapped_device *md);
213
214/*
215 * Event functions.
216 */
217uint32_t dm_get_event_nr(struct mapped_device *md);
218int dm_wait_event(struct mapped_device *md, int event_nr);
219uint32_t dm_next_uevent_seq(struct mapped_device *md);
220void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
221
222/*
223 * Info functions.
224 */
225const char *dm_device_name(struct mapped_device *md);
226int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
227struct gendisk *dm_disk(struct mapped_device *md);
228int dm_suspended(struct mapped_device *md);
229int dm_noflush_suspending(struct dm_target *ti);
230union map_info *dm_get_mapinfo(struct bio *bio);
231
232/*
233 * Geometry functions.
234 */
235int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
236int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
237
238
239/*-----------------------------------------------------------------
240 * Functions for manipulating device-mapper tables.
241 *---------------------------------------------------------------*/
242
243/*
244 * First create an empty table.
245 */
246int dm_table_create(struct dm_table **result, fmode_t mode,
247 unsigned num_targets, struct mapped_device *md);
248
249/*
250 * Then call this once for each target.
251 */
252int dm_table_add_target(struct dm_table *t, const char *type,
253 sector_t start, sector_t len, char *params);
254
255/*
256 * Finally call this to make the table ready for use.
257 */
258int dm_table_complete(struct dm_table *t);
259
260/*
261 * Unplug all devices in a table.
262 */
263void dm_table_unplug_all(struct dm_table *t);
264
265/*
266 * Table reference counting.
267 */
268struct dm_table *dm_get_table(struct mapped_device *md);
269void dm_table_get(struct dm_table *t);
270void dm_table_put(struct dm_table *t);
271
272/*
273 * Queries
274 */
275sector_t dm_table_get_size(struct dm_table *t);
276unsigned int dm_table_get_num_targets(struct dm_table *t);
277fmode_t dm_table_get_mode(struct dm_table *t);
278struct mapped_device *dm_table_get_md(struct dm_table *t);
279
280/*
281 * Trigger an event.
282 */
283void dm_table_event(struct dm_table *t);
284
285/*
286 * The device must be suspended before calling this method.
287 */
288int dm_swap_table(struct mapped_device *md, struct dm_table *t);
289
290/*
291 * A wrapper around vmalloc.
292 */
293void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
294
295/*-----------------------------------------------------------------
296 * Macros.
297 *---------------------------------------------------------------*/
298#define DM_NAME "device-mapper"
299
300#define DMCRIT(f, arg...) \
301 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
302
303#define DMERR(f, arg...) \
304 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
305#define DMERR_LIMIT(f, arg...) \
306 do { \
307 if (printk_ratelimit()) \
308 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
309 f "\n", ## arg); \
310 } while (0)
311
312#define DMWARN(f, arg...) \
313 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
314#define DMWARN_LIMIT(f, arg...) \
315 do { \
316 if (printk_ratelimit()) \
317 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
318 f "\n", ## arg); \
319 } while (0)
320
321#define DMINFO(f, arg...) \
322 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
323#define DMINFO_LIMIT(f, arg...) \
324 do { \
325 if (printk_ratelimit()) \
326 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
327 "\n", ## arg); \
328 } while (0)
329
330#ifdef CONFIG_DM_DEBUG
331# define DMDEBUG(f, arg...) \
332 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
333# define DMDEBUG_LIMIT(f, arg...) \
334 do { \
335 if (printk_ratelimit()) \
336 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
337 "\n", ## arg); \
338 } while (0)
339#else
340# define DMDEBUG(f, arg...) do {} while (0)
341# define DMDEBUG_LIMIT(f, arg...) do {} while (0)
342#endif
343
344#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
345 0 : scnprintf(result + sz, maxlen - sz, x))
346
347#define SECTOR_SHIFT 9
348
349/*
350 * Definitions of return values from target end_io function.
351 */
352#define DM_ENDIO_INCOMPLETE 1
353#define DM_ENDIO_REQUEUE 2
354
355/*
356 * Definitions of return values from target map function.
357 */
358#define DM_MAPIO_SUBMITTED 0
359#define DM_MAPIO_REMAPPED 1
360#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
361
362/*
363 * Ceiling(n / sz)
364 */
365#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
366
367#define dm_sector_div_up(n, sz) ( \
368{ \
369 sector_t _r = ((n) + (sz) - 1); \
370 sector_div(_r, (sz)); \
371 _r; \
372} \
373)
374
375/*
376 * ceiling(n / size) * size
377 */
378#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
379
380#define dm_array_too_big(fixed, obj, num) \
381 ((num) > (UINT_MAX - (fixed)) / (obj))
382
383static inline sector_t to_sector(unsigned long n)
384{
385 return (n >> SECTOR_SHIFT);
386}
387
388static inline unsigned long to_bytes(sector_t n)
389{
390 return (n << SECTOR_SHIFT);
391}
392
393#endif /* _LINUX_DEVICE_MAPPER_H */