Linux kernel mirror (for testing)
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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
120struct target_type {
121 uint64_t features;
122 const char *name;
123 struct module *module;
124 unsigned version[3];
125 dm_ctr_fn ctr;
126 dm_dtr_fn dtr;
127 dm_map_fn map;
128 dm_map_request_fn map_rq;
129 dm_endio_fn end_io;
130 dm_request_endio_fn rq_end_io;
131 dm_flush_fn flush;
132 dm_presuspend_fn presuspend;
133 dm_postsuspend_fn postsuspend;
134 dm_preresume_fn preresume;
135 dm_resume_fn resume;
136 dm_status_fn status;
137 dm_message_fn message;
138 dm_ioctl_fn ioctl;
139 dm_merge_fn merge;
140 dm_busy_fn busy;
141
142 /* For internal device-mapper use. */
143 struct list_head list;
144};
145
146struct io_restrictions {
147 unsigned long bounce_pfn;
148 unsigned long seg_boundary_mask;
149 unsigned max_hw_sectors;
150 unsigned max_sectors;
151 unsigned max_segment_size;
152 unsigned short hardsect_size;
153 unsigned short max_hw_segments;
154 unsigned short max_phys_segments;
155 unsigned char no_cluster; /* inverted so that 0 is default */
156};
157
158struct dm_target {
159 struct dm_table *table;
160 struct target_type *type;
161
162 /* target limits */
163 sector_t begin;
164 sector_t len;
165
166 /* FIXME: turn this into a mask, and merge with io_restrictions */
167 /* Always a power of 2 */
168 sector_t split_io;
169
170 /*
171 * These are automatically filled in by
172 * dm_table_get_device.
173 */
174 struct io_restrictions limits;
175
176 /* target specific data */
177 void *private;
178
179 /* Used to provide an error string from the ctr */
180 char *error;
181};
182
183int dm_register_target(struct target_type *t);
184void dm_unregister_target(struct target_type *t);
185
186/*-----------------------------------------------------------------
187 * Functions for creating and manipulating mapped devices.
188 * Drop the reference with dm_put when you finish with the object.
189 *---------------------------------------------------------------*/
190
191/*
192 * DM_ANY_MINOR chooses the next available minor number.
193 */
194#define DM_ANY_MINOR (-1)
195int dm_create(int minor, struct mapped_device **md);
196
197/*
198 * Reference counting for md.
199 */
200struct mapped_device *dm_get_md(dev_t dev);
201void dm_get(struct mapped_device *md);
202void dm_put(struct mapped_device *md);
203
204/*
205 * An arbitrary pointer may be stored alongside a mapped device.
206 */
207void dm_set_mdptr(struct mapped_device *md, void *ptr);
208void *dm_get_mdptr(struct mapped_device *md);
209
210/*
211 * A device can still be used while suspended, but I/O is deferred.
212 */
213int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
214int dm_resume(struct mapped_device *md);
215
216/*
217 * Event functions.
218 */
219uint32_t dm_get_event_nr(struct mapped_device *md);
220int dm_wait_event(struct mapped_device *md, int event_nr);
221uint32_t dm_next_uevent_seq(struct mapped_device *md);
222void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
223
224/*
225 * Info functions.
226 */
227const char *dm_device_name(struct mapped_device *md);
228int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
229struct gendisk *dm_disk(struct mapped_device *md);
230int dm_suspended(struct mapped_device *md);
231int dm_noflush_suspending(struct dm_target *ti);
232union map_info *dm_get_mapinfo(struct bio *bio);
233
234/*
235 * Geometry functions.
236 */
237int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
238int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
239
240
241/*-----------------------------------------------------------------
242 * Functions for manipulating device-mapper tables.
243 *---------------------------------------------------------------*/
244
245/*
246 * First create an empty table.
247 */
248int dm_table_create(struct dm_table **result, fmode_t mode,
249 unsigned num_targets, struct mapped_device *md);
250
251/*
252 * Then call this once for each target.
253 */
254int dm_table_add_target(struct dm_table *t, const char *type,
255 sector_t start, sector_t len, char *params);
256
257/*
258 * Finally call this to make the table ready for use.
259 */
260int dm_table_complete(struct dm_table *t);
261
262/*
263 * Unplug all devices in a table.
264 */
265void dm_table_unplug_all(struct dm_table *t);
266
267/*
268 * Table reference counting.
269 */
270struct dm_table *dm_get_table(struct mapped_device *md);
271void dm_table_get(struct dm_table *t);
272void dm_table_put(struct dm_table *t);
273
274/*
275 * Queries
276 */
277sector_t dm_table_get_size(struct dm_table *t);
278unsigned int dm_table_get_num_targets(struct dm_table *t);
279fmode_t dm_table_get_mode(struct dm_table *t);
280struct mapped_device *dm_table_get_md(struct dm_table *t);
281
282/*
283 * Trigger an event.
284 */
285void dm_table_event(struct dm_table *t);
286
287/*
288 * The device must be suspended before calling this method.
289 */
290int dm_swap_table(struct mapped_device *md, struct dm_table *t);
291
292/*
293 * A wrapper around vmalloc.
294 */
295void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
296
297/*-----------------------------------------------------------------
298 * Macros.
299 *---------------------------------------------------------------*/
300#define DM_NAME "device-mapper"
301
302#define DMCRIT(f, arg...) \
303 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
304
305#define DMERR(f, arg...) \
306 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
307#define DMERR_LIMIT(f, arg...) \
308 do { \
309 if (printk_ratelimit()) \
310 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
311 f "\n", ## arg); \
312 } while (0)
313
314#define DMWARN(f, arg...) \
315 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
316#define DMWARN_LIMIT(f, arg...) \
317 do { \
318 if (printk_ratelimit()) \
319 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
320 f "\n", ## arg); \
321 } while (0)
322
323#define DMINFO(f, arg...) \
324 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
325#define DMINFO_LIMIT(f, arg...) \
326 do { \
327 if (printk_ratelimit()) \
328 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
329 "\n", ## arg); \
330 } while (0)
331
332#ifdef CONFIG_DM_DEBUG
333# define DMDEBUG(f, arg...) \
334 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
335# define DMDEBUG_LIMIT(f, arg...) \
336 do { \
337 if (printk_ratelimit()) \
338 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
339 "\n", ## arg); \
340 } while (0)
341#else
342# define DMDEBUG(f, arg...) do {} while (0)
343# define DMDEBUG_LIMIT(f, arg...) do {} while (0)
344#endif
345
346#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
347 0 : scnprintf(result + sz, maxlen - sz, x))
348
349#define SECTOR_SHIFT 9
350
351/*
352 * Definitions of return values from target end_io function.
353 */
354#define DM_ENDIO_INCOMPLETE 1
355#define DM_ENDIO_REQUEUE 2
356
357/*
358 * Definitions of return values from target map function.
359 */
360#define DM_MAPIO_SUBMITTED 0
361#define DM_MAPIO_REMAPPED 1
362#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
363
364/*
365 * Ceiling(n / sz)
366 */
367#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
368
369#define dm_sector_div_up(n, sz) ( \
370{ \
371 sector_t _r = ((n) + (sz) - 1); \
372 sector_div(_r, (sz)); \
373 _r; \
374} \
375)
376
377/*
378 * ceiling(n / size) * size
379 */
380#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
381
382#define dm_array_too_big(fixed, obj, num) \
383 ((num) > (UINT_MAX - (fixed)) / (obj))
384
385static inline sector_t to_sector(unsigned long n)
386{
387 return (n >> SECTOR_SHIFT);
388}
389
390static inline unsigned long to_bytes(sector_t n)
391{
392 return (n << SECTOR_SHIFT);
393}
394
395#endif /* _LINUX_DEVICE_MAPPER_H */