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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_dev;
15struct dm_target;
16struct dm_table;
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 unsigned flush_request;
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
45 * = 1: simple remap complete
46 * = 2: The target wants to push back the io
47 */
48typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
49 union map_info *map_context);
50typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
51 union map_info *map_context);
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).
59 * 2 : The target wants to push back the io
60 */
61typedef int (*dm_endio_fn) (struct dm_target *ti,
62 struct bio *bio, int error,
63 union map_info *map_context);
64typedef int (*dm_request_endio_fn) (struct dm_target *ti,
65 struct request *clone, int error,
66 union map_info *map_context);
67
68typedef void (*dm_flush_fn) (struct dm_target *ti);
69typedef void (*dm_presuspend_fn) (struct dm_target *ti);
70typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
71typedef int (*dm_preresume_fn) (struct dm_target *ti);
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
79typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
80 unsigned long arg);
81
82typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
83 struct bio_vec *biovec, int max_size);
84
85typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
86 struct dm_dev *dev,
87 sector_t physical_start,
88 void *data);
89
90typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
91 iterate_devices_callout_fn fn,
92 void *data);
93
94/*
95 * Returns:
96 * 0: The target can handle the next I/O immediately.
97 * 1: The target can't handle the next I/O immediately.
98 */
99typedef int (*dm_busy_fn) (struct dm_target *ti);
100
101void dm_error(const char *message);
102
103/*
104 * Combine device limits.
105 */
106int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
107 sector_t start, void *data);
108
109struct dm_dev {
110 struct block_device *bdev;
111 fmode_t mode;
112 char name[16];
113};
114
115/*
116 * Constructors should call these functions to ensure destination devices
117 * are opened/closed correctly.
118 * FIXME: too many arguments.
119 */
120int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
121 sector_t len, fmode_t mode, struct dm_dev **result);
122void dm_put_device(struct dm_target *ti, struct dm_dev *d);
123
124/*
125 * Information about a target type
126 */
127
128/*
129 * Target features
130 */
131
132struct target_type {
133 uint64_t features;
134 const char *name;
135 struct module *module;
136 unsigned version[3];
137 dm_ctr_fn ctr;
138 dm_dtr_fn dtr;
139 dm_map_fn map;
140 dm_map_request_fn map_rq;
141 dm_endio_fn end_io;
142 dm_request_endio_fn rq_end_io;
143 dm_flush_fn flush;
144 dm_presuspend_fn presuspend;
145 dm_postsuspend_fn postsuspend;
146 dm_preresume_fn preresume;
147 dm_resume_fn resume;
148 dm_status_fn status;
149 dm_message_fn message;
150 dm_ioctl_fn ioctl;
151 dm_merge_fn merge;
152 dm_busy_fn busy;
153 dm_iterate_devices_fn iterate_devices;
154
155 /* For internal device-mapper use. */
156 struct list_head list;
157};
158
159struct dm_target {
160 struct dm_table *table;
161 struct target_type *type;
162
163 /* target limits */
164 sector_t begin;
165 sector_t len;
166
167 /* Always a power of 2 */
168 sector_t split_io;
169
170 /*
171 * A number of zero-length barrier requests that will be submitted
172 * to the target for the purpose of flushing cache.
173 *
174 * The request number will be placed in union map_info->flush_request.
175 * It is a responsibility of the target driver to remap these requests
176 * to the real underlying devices.
177 */
178 unsigned num_flush_requests;
179
180 /* target specific data */
181 void *private;
182
183 /* Used to provide an error string from the ctr */
184 char *error;
185};
186
187int dm_register_target(struct target_type *t);
188void dm_unregister_target(struct target_type *t);
189
190/*-----------------------------------------------------------------
191 * Functions for creating and manipulating mapped devices.
192 * Drop the reference with dm_put when you finish with the object.
193 *---------------------------------------------------------------*/
194
195/*
196 * DM_ANY_MINOR chooses the next available minor number.
197 */
198#define DM_ANY_MINOR (-1)
199int dm_create(int minor, struct mapped_device **md);
200
201/*
202 * Reference counting for md.
203 */
204struct mapped_device *dm_get_md(dev_t dev);
205void dm_get(struct mapped_device *md);
206void dm_put(struct mapped_device *md);
207
208/*
209 * An arbitrary pointer may be stored alongside a mapped device.
210 */
211void dm_set_mdptr(struct mapped_device *md, void *ptr);
212void *dm_get_mdptr(struct mapped_device *md);
213
214/*
215 * A device can still be used while suspended, but I/O is deferred.
216 */
217int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
218int dm_resume(struct mapped_device *md);
219
220/*
221 * Event functions.
222 */
223uint32_t dm_get_event_nr(struct mapped_device *md);
224int dm_wait_event(struct mapped_device *md, int event_nr);
225uint32_t dm_next_uevent_seq(struct mapped_device *md);
226void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
227
228/*
229 * Info functions.
230 */
231const char *dm_device_name(struct mapped_device *md);
232int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
233struct gendisk *dm_disk(struct mapped_device *md);
234int dm_suspended(struct mapped_device *md);
235int dm_noflush_suspending(struct dm_target *ti);
236union map_info *dm_get_mapinfo(struct bio *bio);
237union map_info *dm_get_rq_mapinfo(struct request *rq);
238
239/*
240 * Geometry functions.
241 */
242int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
243int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
244
245
246/*-----------------------------------------------------------------
247 * Functions for manipulating device-mapper tables.
248 *---------------------------------------------------------------*/
249
250/*
251 * First create an empty table.
252 */
253int dm_table_create(struct dm_table **result, fmode_t mode,
254 unsigned num_targets, struct mapped_device *md);
255
256/*
257 * Then call this once for each target.
258 */
259int dm_table_add_target(struct dm_table *t, const char *type,
260 sector_t start, sector_t len, char *params);
261
262/*
263 * Finally call this to make the table ready for use.
264 */
265int dm_table_complete(struct dm_table *t);
266
267/*
268 * Unplug all devices in a table.
269 */
270void dm_table_unplug_all(struct dm_table *t);
271
272/*
273 * Table reference counting.
274 */
275struct dm_table *dm_get_table(struct mapped_device *md);
276void dm_table_get(struct dm_table *t);
277void dm_table_put(struct dm_table *t);
278
279/*
280 * Queries
281 */
282sector_t dm_table_get_size(struct dm_table *t);
283unsigned int dm_table_get_num_targets(struct dm_table *t);
284fmode_t dm_table_get_mode(struct dm_table *t);
285struct mapped_device *dm_table_get_md(struct dm_table *t);
286
287/*
288 * Trigger an event.
289 */
290void dm_table_event(struct dm_table *t);
291
292/*
293 * The device must be suspended before calling this method.
294 */
295int dm_swap_table(struct mapped_device *md, struct dm_table *t);
296
297/*
298 * A wrapper around vmalloc.
299 */
300void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
301
302/*-----------------------------------------------------------------
303 * Macros.
304 *---------------------------------------------------------------*/
305#define DM_NAME "device-mapper"
306
307#define DMCRIT(f, arg...) \
308 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
309
310#define DMERR(f, arg...) \
311 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
312#define DMERR_LIMIT(f, arg...) \
313 do { \
314 if (printk_ratelimit()) \
315 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
316 f "\n", ## arg); \
317 } while (0)
318
319#define DMWARN(f, arg...) \
320 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
321#define DMWARN_LIMIT(f, arg...) \
322 do { \
323 if (printk_ratelimit()) \
324 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
325 f "\n", ## arg); \
326 } while (0)
327
328#define DMINFO(f, arg...) \
329 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
330#define DMINFO_LIMIT(f, arg...) \
331 do { \
332 if (printk_ratelimit()) \
333 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
334 "\n", ## arg); \
335 } while (0)
336
337#ifdef CONFIG_DM_DEBUG
338# define DMDEBUG(f, arg...) \
339 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
340# define DMDEBUG_LIMIT(f, arg...) \
341 do { \
342 if (printk_ratelimit()) \
343 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
344 "\n", ## arg); \
345 } while (0)
346#else
347# define DMDEBUG(f, arg...) do {} while (0)
348# define DMDEBUG_LIMIT(f, arg...) do {} while (0)
349#endif
350
351#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
352 0 : scnprintf(result + sz, maxlen - sz, x))
353
354#define SECTOR_SHIFT 9
355
356/*
357 * Definitions of return values from target end_io function.
358 */
359#define DM_ENDIO_INCOMPLETE 1
360#define DM_ENDIO_REQUEUE 2
361
362/*
363 * Definitions of return values from target map function.
364 */
365#define DM_MAPIO_SUBMITTED 0
366#define DM_MAPIO_REMAPPED 1
367#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
368
369/*
370 * Ceiling(n / sz)
371 */
372#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
373
374#define dm_sector_div_up(n, sz) ( \
375{ \
376 sector_t _r = ((n) + (sz) - 1); \
377 sector_div(_r, (sz)); \
378 _r; \
379} \
380)
381
382/*
383 * ceiling(n / size) * size
384 */
385#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
386
387#define dm_array_too_big(fixed, obj, num) \
388 ((num) > (UINT_MAX - (fixed)) / (obj))
389
390static inline sector_t to_sector(unsigned long n)
391{
392 return (n >> SECTOR_SHIFT);
393}
394
395static inline unsigned long to_bytes(sector_t n)
396{
397 return (n << SECTOR_SHIFT);
398}
399
400/*-----------------------------------------------------------------
401 * Helper for block layer and dm core operations
402 *---------------------------------------------------------------*/
403void dm_dispatch_request(struct request *rq);
404void dm_requeue_unmapped_request(struct request *rq);
405void dm_kill_unmapped_request(struct request *rq, int error);
406int dm_underlying_device_busy(struct request_queue *q);
407
408#endif /* _LINUX_DEVICE_MAPPER_H */