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_target; 15 struct dm_table; 16 struct mapped_device; 17 struct bio_vec; 18 19 typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t; 20 21 union map_info { 22 void *ptr; 23 unsigned long long ll; 24 }; 25 26 /* 27 * In the constructor the target parameter will already have the 28 * table, type, begin and len fields filled in. 29 */ 30 typedef int (*dm_ctr_fn) (struct dm_target *target, 31 unsigned int argc, char **argv); 32 33 /* 34 * The destructor doesn't need to free the dm_target, just 35 * anything hidden ti->private. 36 */ 37 typedef void (*dm_dtr_fn) (struct dm_target *ti); 38 39 /* 40 * The map function must return: 41 * < 0: error 42 * = 0: The target will handle the io by resubmitting it later 43 * = 1: simple remap complete 44 * = 2: The target wants to push back the io 45 */ 46 typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio, 47 union map_info *map_context); 48 49 /* 50 * Returns: 51 * < 0 : error (currently ignored) 52 * 0 : ended successfully 53 * 1 : for some reason the io has still not completed (eg, 54 * multipath target might want to requeue a failed io). 55 * 2 : The target wants to push back the io 56 */ 57 typedef int (*dm_endio_fn) (struct dm_target *ti, 58 struct bio *bio, int error, 59 union map_info *map_context); 60 61 typedef void (*dm_flush_fn) (struct dm_target *ti); 62 typedef void (*dm_presuspend_fn) (struct dm_target *ti); 63 typedef void (*dm_postsuspend_fn) (struct dm_target *ti); 64 typedef int (*dm_preresume_fn) (struct dm_target *ti); 65 typedef void (*dm_resume_fn) (struct dm_target *ti); 66 67 typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type, 68 char *result, unsigned int maxlen); 69 70 typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv); 71 72 typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd, 73 unsigned long arg); 74 75 typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm, 76 struct bio_vec *biovec, int max_size); 77 78 void dm_error(const char *message); 79 80 /* 81 * Combine device limits. 82 */ 83 void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev); 84 85 struct dm_dev { 86 struct block_device *bdev; 87 fmode_t mode; 88 char name[16]; 89 }; 90 91 /* 92 * Constructors should call these functions to ensure destination devices 93 * are opened/closed correctly. 94 * FIXME: too many arguments. 95 */ 96 int dm_get_device(struct dm_target *ti, const char *path, sector_t start, 97 sector_t len, fmode_t mode, struct dm_dev **result); 98 void dm_put_device(struct dm_target *ti, struct dm_dev *d); 99 100 /* 101 * Information about a target type 102 */ 103 struct target_type { 104 const char *name; 105 struct module *module; 106 unsigned version[3]; 107 dm_ctr_fn ctr; 108 dm_dtr_fn dtr; 109 dm_map_fn map; 110 dm_endio_fn end_io; 111 dm_flush_fn flush; 112 dm_presuspend_fn presuspend; 113 dm_postsuspend_fn postsuspend; 114 dm_preresume_fn preresume; 115 dm_resume_fn resume; 116 dm_status_fn status; 117 dm_message_fn message; 118 dm_ioctl_fn ioctl; 119 dm_merge_fn merge; 120 }; 121 122 struct io_restrictions { 123 unsigned long bounce_pfn; 124 unsigned long seg_boundary_mask; 125 unsigned max_hw_sectors; 126 unsigned max_sectors; 127 unsigned max_segment_size; 128 unsigned short hardsect_size; 129 unsigned short max_hw_segments; 130 unsigned short max_phys_segments; 131 unsigned char no_cluster; /* inverted so that 0 is default */ 132 }; 133 134 struct dm_target { 135 struct dm_table *table; 136 struct target_type *type; 137 138 /* target limits */ 139 sector_t begin; 140 sector_t len; 141 142 /* FIXME: turn this into a mask, and merge with io_restrictions */ 143 /* Always a power of 2 */ 144 sector_t split_io; 145 146 /* 147 * These are automatically filled in by 148 * dm_table_get_device. 149 */ 150 struct io_restrictions limits; 151 152 /* target specific data */ 153 void *private; 154 155 /* Used to provide an error string from the ctr */ 156 char *error; 157 }; 158 159 int dm_register_target(struct target_type *t); 160 int dm_unregister_target(struct target_type *t); 161 162 163 /*----------------------------------------------------------------- 164 * Functions for creating and manipulating mapped devices. 165 * Drop the reference with dm_put when you finish with the object. 166 *---------------------------------------------------------------*/ 167 168 /* 169 * DM_ANY_MINOR chooses the next available minor number. 170 */ 171 #define DM_ANY_MINOR (-1) 172 int dm_create(int minor, struct mapped_device **md); 173 174 /* 175 * Reference counting for md. 176 */ 177 struct mapped_device *dm_get_md(dev_t dev); 178 void dm_get(struct mapped_device *md); 179 void dm_put(struct mapped_device *md); 180 181 /* 182 * An arbitrary pointer may be stored alongside a mapped device. 183 */ 184 void dm_set_mdptr(struct mapped_device *md, void *ptr); 185 void *dm_get_mdptr(struct mapped_device *md); 186 187 /* 188 * A device can still be used while suspended, but I/O is deferred. 189 */ 190 int dm_suspend(struct mapped_device *md, unsigned suspend_flags); 191 int dm_resume(struct mapped_device *md); 192 193 /* 194 * Event functions. 195 */ 196 uint32_t dm_get_event_nr(struct mapped_device *md); 197 int dm_wait_event(struct mapped_device *md, int event_nr); 198 uint32_t dm_next_uevent_seq(struct mapped_device *md); 199 void dm_uevent_add(struct mapped_device *md, struct list_head *elist); 200 201 /* 202 * Info functions. 203 */ 204 const char *dm_device_name(struct mapped_device *md); 205 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid); 206 struct gendisk *dm_disk(struct mapped_device *md); 207 int dm_suspended(struct mapped_device *md); 208 int dm_noflush_suspending(struct dm_target *ti); 209 union map_info *dm_get_mapinfo(struct bio *bio); 210 211 /* 212 * Geometry functions. 213 */ 214 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo); 215 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo); 216 217 218 /*----------------------------------------------------------------- 219 * Functions for manipulating device-mapper tables. 220 *---------------------------------------------------------------*/ 221 222 /* 223 * First create an empty table. 224 */ 225 int dm_table_create(struct dm_table **result, fmode_t mode, 226 unsigned num_targets, struct mapped_device *md); 227 228 /* 229 * Then call this once for each target. 230 */ 231 int dm_table_add_target(struct dm_table *t, const char *type, 232 sector_t start, sector_t len, char *params); 233 234 /* 235 * Finally call this to make the table ready for use. 236 */ 237 int dm_table_complete(struct dm_table *t); 238 239 /* 240 * Unplug all devices in a table. 241 */ 242 void dm_table_unplug_all(struct dm_table *t); 243 244 /* 245 * Table reference counting. 246 */ 247 struct dm_table *dm_get_table(struct mapped_device *md); 248 void dm_table_get(struct dm_table *t); 249 void dm_table_put(struct dm_table *t); 250 251 /* 252 * Queries 253 */ 254 sector_t dm_table_get_size(struct dm_table *t); 255 unsigned int dm_table_get_num_targets(struct dm_table *t); 256 fmode_t dm_table_get_mode(struct dm_table *t); 257 struct mapped_device *dm_table_get_md(struct dm_table *t); 258 259 /* 260 * Trigger an event. 261 */ 262 void dm_table_event(struct dm_table *t); 263 264 /* 265 * The device must be suspended before calling this method. 266 */ 267 int dm_swap_table(struct mapped_device *md, struct dm_table *t); 268 269 /* 270 * A wrapper around vmalloc. 271 */ 272 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size); 273 274 /*----------------------------------------------------------------- 275 * Macros. 276 *---------------------------------------------------------------*/ 277 #define DM_NAME "device-mapper" 278 279 #define DMERR(f, arg...) \ 280 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) 281 #define DMERR_LIMIT(f, arg...) \ 282 do { \ 283 if (printk_ratelimit()) \ 284 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \ 285 f "\n", ## arg); \ 286 } while (0) 287 288 #define DMWARN(f, arg...) \ 289 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) 290 #define DMWARN_LIMIT(f, arg...) \ 291 do { \ 292 if (printk_ratelimit()) \ 293 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \ 294 f "\n", ## arg); \ 295 } while (0) 296 297 #define DMINFO(f, arg...) \ 298 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) 299 #define DMINFO_LIMIT(f, arg...) \ 300 do { \ 301 if (printk_ratelimit()) \ 302 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \ 303 "\n", ## arg); \ 304 } while (0) 305 306 #ifdef CONFIG_DM_DEBUG 307 # define DMDEBUG(f, arg...) \ 308 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg) 309 # define DMDEBUG_LIMIT(f, arg...) \ 310 do { \ 311 if (printk_ratelimit()) \ 312 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \ 313 "\n", ## arg); \ 314 } while (0) 315 #else 316 # define DMDEBUG(f, arg...) do {} while (0) 317 # define DMDEBUG_LIMIT(f, arg...) do {} while (0) 318 #endif 319 320 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \ 321 0 : scnprintf(result + sz, maxlen - sz, x)) 322 323 #define SECTOR_SHIFT 9 324 325 /* 326 * Definitions of return values from target end_io function. 327 */ 328 #define DM_ENDIO_INCOMPLETE 1 329 #define DM_ENDIO_REQUEUE 2 330 331 /* 332 * Definitions of return values from target map function. 333 */ 334 #define DM_MAPIO_SUBMITTED 0 335 #define DM_MAPIO_REMAPPED 1 336 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE 337 338 /* 339 * Ceiling(n / sz) 340 */ 341 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz)) 342 343 #define dm_sector_div_up(n, sz) ( \ 344 { \ 345 sector_t _r = ((n) + (sz) - 1); \ 346 sector_div(_r, (sz)); \ 347 _r; \ 348 } \ 349 ) 350 351 /* 352 * ceiling(n / size) * size 353 */ 354 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz)) 355 356 #define dm_array_too_big(fixed, obj, num) \ 357 ((num) > (UINT_MAX - (fixed)) / (obj)) 358 359 static inline sector_t to_sector(unsigned long n) 360 { 361 return (n >> SECTOR_SHIFT); 362 } 363 364 static inline unsigned long to_bytes(sector_t n) 365 { 366 return (n << SECTOR_SHIFT); 367 } 368 369 #endif /* _LINUX_DEVICE_MAPPER_H */ 370