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