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 target_request_nr; 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 */ 122 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, 123 struct dm_dev **result); 124 void dm_put_device(struct dm_target *ti, struct dm_dev *d); 125 126 /* 127 * Information about a target type 128 */ 129 130 /* 131 * Target features 132 */ 133 134 struct target_type { 135 uint64_t features; 136 const char *name; 137 struct module *module; 138 unsigned version[3]; 139 dm_ctr_fn ctr; 140 dm_dtr_fn dtr; 141 dm_map_fn map; 142 dm_map_request_fn map_rq; 143 dm_endio_fn end_io; 144 dm_request_endio_fn rq_end_io; 145 dm_flush_fn flush; 146 dm_presuspend_fn presuspend; 147 dm_postsuspend_fn postsuspend; 148 dm_preresume_fn preresume; 149 dm_resume_fn resume; 150 dm_status_fn status; 151 dm_message_fn message; 152 dm_ioctl_fn ioctl; 153 dm_merge_fn merge; 154 dm_busy_fn busy; 155 dm_iterate_devices_fn iterate_devices; 156 dm_io_hints_fn io_hints; 157 158 /* For internal device-mapper use. */ 159 struct list_head list; 160 }; 161 162 struct dm_target { 163 struct dm_table *table; 164 struct target_type *type; 165 166 /* target limits */ 167 sector_t begin; 168 sector_t len; 169 170 /* Always a power of 2 */ 171 sector_t split_io; 172 173 /* 174 * A number of zero-length barrier requests that will be submitted 175 * to the target for the purpose of flushing cache. 176 * 177 * The request number will be placed in union map_info->target_request_nr. 178 * It is a responsibility of the target driver to remap these requests 179 * to the real underlying devices. 180 */ 181 unsigned num_flush_requests; 182 183 /* 184 * The number of discard requests that will be submitted to the 185 * target. map_info->request_nr is used just like num_flush_requests. 186 */ 187 unsigned num_discard_requests; 188 189 /* target specific data */ 190 void *private; 191 192 /* Used to provide an error string from the ctr */ 193 char *error; 194 }; 195 196 int dm_register_target(struct target_type *t); 197 void dm_unregister_target(struct target_type *t); 198 199 /*----------------------------------------------------------------- 200 * Functions for creating and manipulating mapped devices. 201 * Drop the reference with dm_put when you finish with the object. 202 *---------------------------------------------------------------*/ 203 204 /* 205 * DM_ANY_MINOR chooses the next available minor number. 206 */ 207 #define DM_ANY_MINOR (-1) 208 int dm_create(int minor, struct mapped_device **md); 209 210 /* 211 * Reference counting for md. 212 */ 213 struct mapped_device *dm_get_md(dev_t dev); 214 void dm_get(struct mapped_device *md); 215 void dm_put(struct mapped_device *md); 216 217 /* 218 * An arbitrary pointer may be stored alongside a mapped device. 219 */ 220 void dm_set_mdptr(struct mapped_device *md, void *ptr); 221 void *dm_get_mdptr(struct mapped_device *md); 222 223 /* 224 * A device can still be used while suspended, but I/O is deferred. 225 */ 226 int dm_suspend(struct mapped_device *md, unsigned suspend_flags); 227 int dm_resume(struct mapped_device *md); 228 229 /* 230 * Event functions. 231 */ 232 uint32_t dm_get_event_nr(struct mapped_device *md); 233 int dm_wait_event(struct mapped_device *md, int event_nr); 234 uint32_t dm_next_uevent_seq(struct mapped_device *md); 235 void dm_uevent_add(struct mapped_device *md, struct list_head *elist); 236 237 /* 238 * Info functions. 239 */ 240 const char *dm_device_name(struct mapped_device *md); 241 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid); 242 struct gendisk *dm_disk(struct mapped_device *md); 243 int dm_suspended(struct dm_target *ti); 244 int dm_noflush_suspending(struct dm_target *ti); 245 union map_info *dm_get_mapinfo(struct bio *bio); 246 union map_info *dm_get_rq_mapinfo(struct request *rq); 247 248 /* 249 * Geometry functions. 250 */ 251 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo); 252 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo); 253 254 255 /*----------------------------------------------------------------- 256 * Functions for manipulating device-mapper tables. 257 *---------------------------------------------------------------*/ 258 259 /* 260 * First create an empty table. 261 */ 262 int dm_table_create(struct dm_table **result, fmode_t mode, 263 unsigned num_targets, struct mapped_device *md); 264 265 /* 266 * Then call this once for each target. 267 */ 268 int dm_table_add_target(struct dm_table *t, const char *type, 269 sector_t start, sector_t len, char *params); 270 271 /* 272 * Finally call this to make the table ready for use. 273 */ 274 int dm_table_complete(struct dm_table *t); 275 276 /* 277 * Unplug all devices in a table. 278 */ 279 void dm_table_unplug_all(struct dm_table *t); 280 281 /* 282 * Table reference counting. 283 */ 284 struct dm_table *dm_get_live_table(struct mapped_device *md); 285 void dm_table_get(struct dm_table *t); 286 void dm_table_put(struct dm_table *t); 287 288 /* 289 * Queries 290 */ 291 sector_t dm_table_get_size(struct dm_table *t); 292 unsigned int dm_table_get_num_targets(struct dm_table *t); 293 fmode_t dm_table_get_mode(struct dm_table *t); 294 struct mapped_device *dm_table_get_md(struct dm_table *t); 295 296 /* 297 * Trigger an event. 298 */ 299 void dm_table_event(struct dm_table *t); 300 301 /* 302 * The device must be suspended before calling this method. 303 * Returns the previous table, which the caller must destroy. 304 */ 305 struct dm_table *dm_swap_table(struct mapped_device *md, 306 struct dm_table *t); 307 308 /* 309 * A wrapper around vmalloc. 310 */ 311 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size); 312 313 /*----------------------------------------------------------------- 314 * Macros. 315 *---------------------------------------------------------------*/ 316 #define DM_NAME "device-mapper" 317 318 #define DMCRIT(f, arg...) \ 319 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) 320 321 #define DMERR(f, arg...) \ 322 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) 323 #define DMERR_LIMIT(f, arg...) \ 324 do { \ 325 if (printk_ratelimit()) \ 326 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \ 327 f "\n", ## arg); \ 328 } while (0) 329 330 #define DMWARN(f, arg...) \ 331 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) 332 #define DMWARN_LIMIT(f, arg...) \ 333 do { \ 334 if (printk_ratelimit()) \ 335 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \ 336 f "\n", ## arg); \ 337 } while (0) 338 339 #define DMINFO(f, arg...) \ 340 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) 341 #define DMINFO_LIMIT(f, arg...) \ 342 do { \ 343 if (printk_ratelimit()) \ 344 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \ 345 "\n", ## arg); \ 346 } while (0) 347 348 #ifdef CONFIG_DM_DEBUG 349 # define DMDEBUG(f, arg...) \ 350 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg) 351 # define DMDEBUG_LIMIT(f, arg...) \ 352 do { \ 353 if (printk_ratelimit()) \ 354 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \ 355 "\n", ## arg); \ 356 } while (0) 357 #else 358 # define DMDEBUG(f, arg...) do {} while (0) 359 # define DMDEBUG_LIMIT(f, arg...) do {} while (0) 360 #endif 361 362 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \ 363 0 : scnprintf(result + sz, maxlen - sz, x)) 364 365 #define SECTOR_SHIFT 9 366 367 /* 368 * Definitions of return values from target end_io function. 369 */ 370 #define DM_ENDIO_INCOMPLETE 1 371 #define DM_ENDIO_REQUEUE 2 372 373 /* 374 * Definitions of return values from target map function. 375 */ 376 #define DM_MAPIO_SUBMITTED 0 377 #define DM_MAPIO_REMAPPED 1 378 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE 379 380 /* 381 * Ceiling(n / sz) 382 */ 383 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz)) 384 385 #define dm_sector_div_up(n, sz) ( \ 386 { \ 387 sector_t _r = ((n) + (sz) - 1); \ 388 sector_div(_r, (sz)); \ 389 _r; \ 390 } \ 391 ) 392 393 /* 394 * ceiling(n / size) * size 395 */ 396 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz)) 397 398 #define dm_array_too_big(fixed, obj, num) \ 399 ((num) > (UINT_MAX - (fixed)) / (obj)) 400 401 /* 402 * Sector offset taken relative to the start of the target instead of 403 * relative to the start of the device. 404 */ 405 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin) 406 407 static inline sector_t to_sector(unsigned long n) 408 { 409 return (n >> SECTOR_SHIFT); 410 } 411 412 static inline unsigned long to_bytes(sector_t n) 413 { 414 return (n << SECTOR_SHIFT); 415 } 416 417 /*----------------------------------------------------------------- 418 * Helper for block layer and dm core operations 419 *---------------------------------------------------------------*/ 420 void dm_dispatch_request(struct request *rq); 421 void dm_requeue_unmapped_request(struct request *rq); 422 void dm_kill_unmapped_request(struct request *rq, int error); 423 int dm_underlying_device_busy(struct request_queue *q); 424 425 #endif /* _LINUX_DEVICE_MAPPER_H */ 426