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 /* 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 */ 99 typedef int (*dm_busy_fn) (struct dm_target *ti); 100 101 void dm_error(const char *message); 102 103 /* 104 * Combine device limits. 105 */ 106 int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev, 107 sector_t start, sector_t len, void *data); 108 109 struct 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 */ 120 int dm_get_device(struct dm_target *ti, const char *path, sector_t start, 121 sector_t len, fmode_t mode, struct dm_dev **result); 122 void 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 */ 131 132 struct 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 }; 158 159 struct 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 }; 186 187 int dm_register_target(struct target_type *t); 188 void 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) 199 int dm_create(int minor, struct mapped_device **md); 200 201 /* 202 * Reference counting for md. 203 */ 204 struct mapped_device *dm_get_md(dev_t dev); 205 void dm_get(struct mapped_device *md); 206 void dm_put(struct mapped_device *md); 207 208 /* 209 * An arbitrary pointer may be stored alongside a mapped device. 210 */ 211 void dm_set_mdptr(struct mapped_device *md, void *ptr); 212 void *dm_get_mdptr(struct mapped_device *md); 213 214 /* 215 * A device can still be used while suspended, but I/O is deferred. 216 */ 217 int dm_suspend(struct mapped_device *md, unsigned suspend_flags); 218 int dm_resume(struct mapped_device *md); 219 220 /* 221 * Event functions. 222 */ 223 uint32_t dm_get_event_nr(struct mapped_device *md); 224 int dm_wait_event(struct mapped_device *md, int event_nr); 225 uint32_t dm_next_uevent_seq(struct mapped_device *md); 226 void dm_uevent_add(struct mapped_device *md, struct list_head *elist); 227 228 /* 229 * Info functions. 230 */ 231 const char *dm_device_name(struct mapped_device *md); 232 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid); 233 struct gendisk *dm_disk(struct mapped_device *md); 234 int dm_suspended(struct mapped_device *md); 235 int dm_noflush_suspending(struct dm_target *ti); 236 union map_info *dm_get_mapinfo(struct bio *bio); 237 union map_info *dm_get_rq_mapinfo(struct request *rq); 238 239 /* 240 * Geometry functions. 241 */ 242 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo); 243 int 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 */ 253 int 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 */ 259 int 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 */ 265 int dm_table_complete(struct dm_table *t); 266 267 /* 268 * Unplug all devices in a table. 269 */ 270 void dm_table_unplug_all(struct dm_table *t); 271 272 /* 273 * Table reference counting. 274 */ 275 struct dm_table *dm_get_table(struct mapped_device *md); 276 void dm_table_get(struct dm_table *t); 277 void dm_table_put(struct dm_table *t); 278 279 /* 280 * Queries 281 */ 282 sector_t dm_table_get_size(struct dm_table *t); 283 unsigned int dm_table_get_num_targets(struct dm_table *t); 284 fmode_t dm_table_get_mode(struct dm_table *t); 285 struct mapped_device *dm_table_get_md(struct dm_table *t); 286 287 /* 288 * Trigger an event. 289 */ 290 void dm_table_event(struct dm_table *t); 291 292 /* 293 * The device must be suspended before calling this method. 294 */ 295 int dm_swap_table(struct mapped_device *md, struct dm_table *t); 296 297 /* 298 * A wrapper around vmalloc. 299 */ 300 void *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)) 389 390 static inline sector_t to_sector(unsigned long n) 391 { 392 return (n >> SECTOR_SHIFT); 393 } 394 395 static 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 *---------------------------------------------------------------*/ 403 void dm_dispatch_request(struct request *rq); 404 void dm_requeue_unmapped_request(struct request *rq); 405 void dm_kill_unmapped_request(struct request *rq, int error); 406 int dm_underlying_device_busy(struct request_queue *q); 407 408 #endif /* _LINUX_DEVICE_MAPPER_H */ 409