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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 | ||
14 | struct dm_dev; | |
15 | struct dm_target; | |
16 | struct dm_table; | |
17 | struct mapped_device; | |
18 | struct bio_vec; | |
19 | ||
20 | typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t; | |
21 | ||
22 | union 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 | */ | |
32 | typedef 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 | */ | |
39 | typedef 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 | */ | |
48 | typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio, | |
49 | union map_info *map_context); | |
50 | typedef 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 | */ | |
61 | typedef int (*dm_endio_fn) (struct dm_target *ti, | |
62 | struct bio *bio, int error, | |
63 | union map_info *map_context); | |
64 | typedef int (*dm_request_endio_fn) (struct dm_target *ti, | |
65 | struct request *clone, int error, | |
66 | union map_info *map_context); | |
67 | ||
68 | typedef void (*dm_flush_fn) (struct dm_target *ti); | |
69 | typedef void (*dm_presuspend_fn) (struct dm_target *ti); | |
70 | typedef void (*dm_postsuspend_fn) (struct dm_target *ti); | |
71 | typedef int (*dm_preresume_fn) (struct dm_target *ti); | |
72 | typedef void (*dm_resume_fn) (struct dm_target *ti); | |
73 | ||
74 | typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type, | |
75 | char *result, unsigned int maxlen); | |
76 | ||
77 | typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv); | |
78 | ||
79 | typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd, | |
80 | unsigned long arg); | |
81 | ||
82 | typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm, | |
83 | struct bio_vec *biovec, int max_size); | |
84 | ||
85 | typedef int (*iterate_devices_callout_fn) (struct dm_target *ti, | |
86 | struct dm_dev *dev, | |
87 | sector_t start, sector_t len, | |
88 | void *data); | |
89 | ||
90 | typedef int (*dm_iterate_devices_fn) (struct dm_target *ti, | |
91 | iterate_devices_callout_fn fn, | |
92 | void *data); | |
93 | ||
94 | typedef void (*dm_io_hints_fn) (struct dm_target *ti, | |
95 | struct queue_limits *limits); | |
96 | ||
97 | /* | |
98 | * Returns: | |
99 | * 0: The target can handle the next I/O immediately. | |
100 | * 1: The target can't handle the next I/O immediately. | |
101 | */ | |
102 | typedef int (*dm_busy_fn) (struct dm_target *ti); | |
103 | ||
104 | void dm_error(const char *message); | |
105 | ||
106 | /* | |
107 | * Combine device limits. | |
108 | */ | |
109 | int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev, | |
110 | sector_t start, sector_t len, void *data); | |
111 | ||
112 | struct dm_dev { | |
113 | struct block_device *bdev; | |
114 | fmode_t mode; | |
115 | char name[16]; | |
116 | }; | |
117 | ||
118 | /* | |
119 | * Constructors should call these functions to ensure destination devices | |
120 | * are opened/closed correctly. | |
121 | * FIXME: too many arguments. | |
122 | */ | |
123 | int dm_get_device(struct dm_target *ti, const char *path, sector_t start, | |
124 | sector_t len, fmode_t mode, struct dm_dev **result); | |
125 | void dm_put_device(struct dm_target *ti, struct dm_dev *d); | |
126 | ||
127 | /* | |
128 | * Information about a target type | |
129 | */ | |
130 | ||
131 | /* | |
132 | * Target features | |
133 | */ | |
134 | ||
135 | struct target_type { | |
136 | uint64_t features; | |
137 | const char *name; | |
138 | struct module *module; | |
139 | unsigned version[3]; | |
140 | dm_ctr_fn ctr; | |
141 | dm_dtr_fn dtr; | |
142 | dm_map_fn map; | |
143 | dm_map_request_fn map_rq; | |
144 | dm_endio_fn end_io; | |
145 | dm_request_endio_fn rq_end_io; | |
146 | dm_flush_fn flush; | |
147 | dm_presuspend_fn presuspend; | |
148 | dm_postsuspend_fn postsuspend; | |
149 | dm_preresume_fn preresume; | |
150 | dm_resume_fn resume; | |
151 | dm_status_fn status; | |
152 | dm_message_fn message; | |
153 | dm_ioctl_fn ioctl; | |
154 | dm_merge_fn merge; | |
155 | dm_busy_fn busy; | |
156 | dm_iterate_devices_fn iterate_devices; | |
157 | dm_io_hints_fn io_hints; | |
158 | ||
159 | /* For internal device-mapper use. */ | |
160 | struct list_head list; | |
161 | }; | |
162 | ||
163 | struct dm_target { | |
164 | struct dm_table *table; | |
165 | struct target_type *type; | |
166 | ||
167 | /* target limits */ | |
168 | sector_t begin; | |
169 | sector_t len; | |
170 | ||
171 | /* Always a power of 2 */ | |
172 | sector_t split_io; | |
173 | ||
174 | /* | |
175 | * A number of zero-length barrier requests that will be submitted | |
176 | * to the target for the purpose of flushing cache. | |
177 | * | |
178 | * The request number will be placed in union map_info->flush_request. | |
179 | * It is a responsibility of the target driver to remap these requests | |
180 | * to the real underlying devices. | |
181 | */ | |
182 | unsigned num_flush_requests; | |
183 | ||
184 | /* target specific data */ | |
185 | void *private; | |
186 | ||
187 | /* Used to provide an error string from the ctr */ | |
188 | char *error; | |
189 | }; | |
190 | ||
191 | int dm_register_target(struct target_type *t); | |
192 | void dm_unregister_target(struct target_type *t); | |
193 | ||
194 | /*----------------------------------------------------------------- | |
195 | * Functions for creating and manipulating mapped devices. | |
196 | * Drop the reference with dm_put when you finish with the object. | |
197 | *---------------------------------------------------------------*/ | |
198 | ||
199 | /* | |
200 | * DM_ANY_MINOR chooses the next available minor number. | |
201 | */ | |
202 | #define DM_ANY_MINOR (-1) | |
203 | int dm_create(int minor, struct mapped_device **md); | |
204 | ||
205 | /* | |
206 | * Reference counting for md. | |
207 | */ | |
208 | struct mapped_device *dm_get_md(dev_t dev); | |
209 | void dm_get(struct mapped_device *md); | |
210 | void dm_put(struct mapped_device *md); | |
211 | ||
212 | /* | |
213 | * An arbitrary pointer may be stored alongside a mapped device. | |
214 | */ | |
215 | void dm_set_mdptr(struct mapped_device *md, void *ptr); | |
216 | void *dm_get_mdptr(struct mapped_device *md); | |
217 | ||
218 | /* | |
219 | * A device can still be used while suspended, but I/O is deferred. | |
220 | */ | |
221 | int dm_suspend(struct mapped_device *md, unsigned suspend_flags); | |
222 | int dm_resume(struct mapped_device *md); | |
223 | ||
224 | /* | |
225 | * Event functions. | |
226 | */ | |
227 | uint32_t dm_get_event_nr(struct mapped_device *md); | |
228 | int dm_wait_event(struct mapped_device *md, int event_nr); | |
229 | uint32_t dm_next_uevent_seq(struct mapped_device *md); | |
230 | void dm_uevent_add(struct mapped_device *md, struct list_head *elist); | |
231 | ||
232 | /* | |
233 | * Info functions. | |
234 | */ | |
235 | const char *dm_device_name(struct mapped_device *md); | |
236 | int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid); | |
237 | struct gendisk *dm_disk(struct mapped_device *md); | |
238 | int dm_suspended(struct dm_target *ti); | |
239 | int dm_noflush_suspending(struct dm_target *ti); | |
240 | union map_info *dm_get_mapinfo(struct bio *bio); | |
241 | union map_info *dm_get_rq_mapinfo(struct request *rq); | |
242 | ||
243 | /* | |
244 | * Geometry functions. | |
245 | */ | |
246 | int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo); | |
247 | int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo); | |
248 | ||
249 | ||
250 | /*----------------------------------------------------------------- | |
251 | * Functions for manipulating device-mapper tables. | |
252 | *---------------------------------------------------------------*/ | |
253 | ||
254 | /* | |
255 | * First create an empty table. | |
256 | */ | |
257 | int dm_table_create(struct dm_table **result, fmode_t mode, | |
258 | unsigned num_targets, struct mapped_device *md); | |
259 | ||
260 | /* | |
261 | * Then call this once for each target. | |
262 | */ | |
263 | int dm_table_add_target(struct dm_table *t, const char *type, | |
264 | sector_t start, sector_t len, char *params); | |
265 | ||
266 | /* | |
267 | * Finally call this to make the table ready for use. | |
268 | */ | |
269 | int dm_table_complete(struct dm_table *t); | |
270 | ||
271 | /* | |
272 | * Unplug all devices in a table. | |
273 | */ | |
274 | void dm_table_unplug_all(struct dm_table *t); | |
275 | ||
276 | /* | |
277 | * Table reference counting. | |
278 | */ | |
279 | struct dm_table *dm_get_live_table(struct mapped_device *md); | |
280 | void dm_table_get(struct dm_table *t); | |
281 | void dm_table_put(struct dm_table *t); | |
282 | ||
283 | /* | |
284 | * Queries | |
285 | */ | |
286 | sector_t dm_table_get_size(struct dm_table *t); | |
287 | unsigned int dm_table_get_num_targets(struct dm_table *t); | |
288 | fmode_t dm_table_get_mode(struct dm_table *t); | |
289 | struct mapped_device *dm_table_get_md(struct dm_table *t); | |
290 | ||
291 | /* | |
292 | * Trigger an event. | |
293 | */ | |
294 | void dm_table_event(struct dm_table *t); | |
295 | ||
296 | /* | |
297 | * The device must be suspended before calling this method. | |
298 | * Returns the previous table, which the caller must destroy. | |
299 | */ | |
300 | struct dm_table *dm_swap_table(struct mapped_device *md, | |
301 | struct dm_table *t); | |
302 | ||
303 | /* | |
304 | * A wrapper around vmalloc. | |
305 | */ | |
306 | void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size); | |
307 | ||
308 | /*----------------------------------------------------------------- | |
309 | * Macros. | |
310 | *---------------------------------------------------------------*/ | |
311 | #define DM_NAME "device-mapper" | |
312 | ||
313 | #define DMCRIT(f, arg...) \ | |
314 | printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) | |
315 | ||
316 | #define DMERR(f, arg...) \ | |
317 | printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) | |
318 | #define DMERR_LIMIT(f, arg...) \ | |
319 | do { \ | |
320 | if (printk_ratelimit()) \ | |
321 | printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \ | |
322 | f "\n", ## arg); \ | |
323 | } while (0) | |
324 | ||
325 | #define DMWARN(f, arg...) \ | |
326 | printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) | |
327 | #define DMWARN_LIMIT(f, arg...) \ | |
328 | do { \ | |
329 | if (printk_ratelimit()) \ | |
330 | printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \ | |
331 | f "\n", ## arg); \ | |
332 | } while (0) | |
333 | ||
334 | #define DMINFO(f, arg...) \ | |
335 | printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) | |
336 | #define DMINFO_LIMIT(f, arg...) \ | |
337 | do { \ | |
338 | if (printk_ratelimit()) \ | |
339 | printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \ | |
340 | "\n", ## arg); \ | |
341 | } while (0) | |
342 | ||
343 | #ifdef CONFIG_DM_DEBUG | |
344 | # define DMDEBUG(f, arg...) \ | |
345 | printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg) | |
346 | # define DMDEBUG_LIMIT(f, arg...) \ | |
347 | do { \ | |
348 | if (printk_ratelimit()) \ | |
349 | printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \ | |
350 | "\n", ## arg); \ | |
351 | } while (0) | |
352 | #else | |
353 | # define DMDEBUG(f, arg...) do {} while (0) | |
354 | # define DMDEBUG_LIMIT(f, arg...) do {} while (0) | |
355 | #endif | |
356 | ||
357 | #define DMEMIT(x...) sz += ((sz >= maxlen) ? \ | |
358 | 0 : scnprintf(result + sz, maxlen - sz, x)) | |
359 | ||
360 | #define SECTOR_SHIFT 9 | |
361 | ||
362 | /* | |
363 | * Definitions of return values from target end_io function. | |
364 | */ | |
365 | #define DM_ENDIO_INCOMPLETE 1 | |
366 | #define DM_ENDIO_REQUEUE 2 | |
367 | ||
368 | /* | |
369 | * Definitions of return values from target map function. | |
370 | */ | |
371 | #define DM_MAPIO_SUBMITTED 0 | |
372 | #define DM_MAPIO_REMAPPED 1 | |
373 | #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE | |
374 | ||
375 | /* | |
376 | * Ceiling(n / sz) | |
377 | */ | |
378 | #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz)) | |
379 | ||
380 | #define dm_sector_div_up(n, sz) ( \ | |
381 | { \ | |
382 | sector_t _r = ((n) + (sz) - 1); \ | |
383 | sector_div(_r, (sz)); \ | |
384 | _r; \ | |
385 | } \ | |
386 | ) | |
387 | ||
388 | /* | |
389 | * ceiling(n / size) * size | |
390 | */ | |
391 | #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz)) | |
392 | ||
393 | #define dm_array_too_big(fixed, obj, num) \ | |
394 | ((num) > (UINT_MAX - (fixed)) / (obj)) | |
395 | ||
396 | static inline sector_t to_sector(unsigned long n) | |
397 | { | |
398 | return (n >> SECTOR_SHIFT); | |
399 | } | |
400 | ||
401 | static inline unsigned long to_bytes(sector_t n) | |
402 | { | |
403 | return (n << SECTOR_SHIFT); | |
404 | } | |
405 | ||
406 | /*----------------------------------------------------------------- | |
407 | * Helper for block layer and dm core operations | |
408 | *---------------------------------------------------------------*/ | |
409 | void dm_dispatch_request(struct request *rq); | |
410 | void dm_requeue_unmapped_request(struct request *rq); | |
411 | void dm_kill_unmapped_request(struct request *rq, int error); | |
412 | int dm_underlying_device_busy(struct request_queue *q); | |
413 | ||
414 | #endif /* _LINUX_DEVICE_MAPPER_H */ |