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