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 */ 415