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, struct inode *inode, 73 struct file *filp, unsigned int cmd, 74 unsigned long arg); 75 76 typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm, 77 struct bio_vec *biovec, int max_size); 78 79 void dm_error(const char *message); 80 81 /* 82 * Combine device limits. 83 */ 84 void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev); 85 86 struct dm_dev { 87 struct block_device *bdev; 88 int mode; 89 char name[16]; 90 }; 91 92 /* 93 * Constructors should call these functions to ensure destination devices 94 * are opened/closed correctly. 95 * FIXME: too many arguments. 96 */ 97 int dm_get_device(struct dm_target *ti, const char *path, sector_t start, 98 sector_t len, int mode, struct dm_dev **result); 99 void dm_put_device(struct dm_target *ti, struct dm_dev *d); 100 101 /* 102 * Information about a target type 103 */ 104 struct target_type { 105 const char *name; 106 struct module *module; 107 unsigned version[3]; 108 dm_ctr_fn ctr; 109 dm_dtr_fn dtr; 110 dm_map_fn map; 111 dm_endio_fn end_io; 112 dm_flush_fn flush; 113 dm_presuspend_fn presuspend; 114 dm_postsuspend_fn postsuspend; 115 dm_preresume_fn preresume; 116 dm_resume_fn resume; 117 dm_status_fn status; 118 dm_message_fn message; 119 dm_ioctl_fn ioctl; 120 dm_merge_fn merge; 121 }; 122 123 struct io_restrictions { 124 unsigned long bounce_pfn; 125 unsigned long seg_boundary_mask; 126 unsigned max_hw_sectors; 127 unsigned max_sectors; 128 unsigned max_segment_size; 129 unsigned short hardsect_size; 130 unsigned short max_hw_segments; 131 unsigned short max_phys_segments; 132 unsigned char no_cluster; /* inverted so that 0 is default */ 133 }; 134 135 struct dm_target { 136 struct dm_table *table; 137 struct target_type *type; 138 139 /* target limits */ 140 sector_t begin; 141 sector_t len; 142 143 /* FIXME: turn this into a mask, and merge with io_restrictions */ 144 /* Always a power of 2 */ 145 sector_t split_io; 146 147 /* 148 * These are automatically filled in by 149 * dm_table_get_device. 150 */ 151 struct io_restrictions limits; 152 153 /* target specific data */ 154 void *private; 155 156 /* Used to provide an error string from the ctr */ 157 char *error; 158 }; 159 160 int dm_register_target(struct target_type *t); 161 int dm_unregister_target(struct target_type *t); 162 163 164 /*----------------------------------------------------------------- 165 * Functions for creating and manipulating mapped devices. 166 * Drop the reference with dm_put when you finish with the object. 167 *---------------------------------------------------------------*/ 168 169 /* 170 * DM_ANY_MINOR chooses the next available minor number. 171 */ 172 #define DM_ANY_MINOR (-1) 173 int dm_create(int minor, struct mapped_device **md); 174 175 /* 176 * Reference counting for md. 177 */ 178 struct mapped_device *dm_get_md(dev_t dev); 179 void dm_get(struct mapped_device *md); 180 void dm_put(struct mapped_device *md); 181 182 /* 183 * An arbitrary pointer may be stored alongside a mapped device. 184 */ 185 void dm_set_mdptr(struct mapped_device *md, void *ptr); 186 void *dm_get_mdptr(struct mapped_device *md); 187 188 /* 189 * A device can still be used while suspended, but I/O is deferred. 190 */ 191 int dm_suspend(struct mapped_device *md, unsigned suspend_flags); 192 int dm_resume(struct mapped_device *md); 193 194 /* 195 * Event functions. 196 */ 197 uint32_t dm_get_event_nr(struct mapped_device *md); 198 int dm_wait_event(struct mapped_device *md, int event_nr); 199 uint32_t dm_next_uevent_seq(struct mapped_device *md); 200 void dm_uevent_add(struct mapped_device *md, struct list_head *elist); 201 202 /* 203 * Info functions. 204 */ 205 const char *dm_device_name(struct mapped_device *md); 206 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid); 207 struct gendisk *dm_disk(struct mapped_device *md); 208 int dm_suspended(struct mapped_device *md); 209 int dm_noflush_suspending(struct dm_target *ti); 210 union map_info *dm_get_mapinfo(struct bio *bio); 211 212 /* 213 * Geometry functions. 214 */ 215 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo); 216 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo); 217 218 219 /*----------------------------------------------------------------- 220 * Functions for manipulating device-mapper tables. 221 *---------------------------------------------------------------*/ 222 223 /* 224 * First create an empty table. 225 */ 226 int dm_table_create(struct dm_table **result, int mode, 227 unsigned num_targets, struct mapped_device *md); 228 229 /* 230 * Then call this once for each target. 231 */ 232 int dm_table_add_target(struct dm_table *t, const char *type, 233 sector_t start, sector_t len, char *params); 234 235 /* 236 * Finally call this to make the table ready for use. 237 */ 238 int dm_table_complete(struct dm_table *t); 239 240 /* 241 * Unplug all devices in a table. 242 */ 243 void dm_table_unplug_all(struct dm_table *t); 244 245 /* 246 * Table reference counting. 247 */ 248 struct dm_table *dm_get_table(struct mapped_device *md); 249 void dm_table_get(struct dm_table *t); 250 void dm_table_put(struct dm_table *t); 251 252 /* 253 * Queries 254 */ 255 sector_t dm_table_get_size(struct dm_table *t); 256 unsigned int dm_table_get_num_targets(struct dm_table *t); 257 int dm_table_get_mode(struct dm_table *t); 258 struct mapped_device *dm_table_get_md(struct dm_table *t); 259 260 /* 261 * Trigger an event. 262 */ 263 void dm_table_event(struct dm_table *t); 264 265 /* 266 * The device must be suspended before calling this method. 267 */ 268 int dm_swap_table(struct mapped_device *md, struct dm_table *t); 269 270 /* 271 * A wrapper around vmalloc. 272 */ 273 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size); 274 275 /*----------------------------------------------------------------- 276 * Macros. 277 *---------------------------------------------------------------*/ 278 #define DM_NAME "device-mapper" 279 280 #define DMERR(f, arg...) \ 281 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) 282 #define DMERR_LIMIT(f, arg...) \ 283 do { \ 284 if (printk_ratelimit()) \ 285 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \ 286 f "\n", ## arg); \ 287 } while (0) 288 289 #define DMWARN(f, arg...) \ 290 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) 291 #define DMWARN_LIMIT(f, arg...) \ 292 do { \ 293 if (printk_ratelimit()) \ 294 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \ 295 f "\n", ## arg); \ 296 } while (0) 297 298 #define DMINFO(f, arg...) \ 299 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) 300 #define DMINFO_LIMIT(f, arg...) \ 301 do { \ 302 if (printk_ratelimit()) \ 303 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \ 304 "\n", ## arg); \ 305 } while (0) 306 307 #ifdef CONFIG_DM_DEBUG 308 # define DMDEBUG(f, arg...) \ 309 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg) 310 # define DMDEBUG_LIMIT(f, arg...) \ 311 do { \ 312 if (printk_ratelimit()) \ 313 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \ 314 "\n", ## arg); \ 315 } while (0) 316 #else 317 # define DMDEBUG(f, arg...) do {} while (0) 318 # define DMDEBUG_LIMIT(f, arg...) do {} while (0) 319 #endif 320 321 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \ 322 0 : scnprintf(result + sz, maxlen - sz, x)) 323 324 #define SECTOR_SHIFT 9 325 326 /* 327 * Definitions of return values from target end_io function. 328 */ 329 #define DM_ENDIO_INCOMPLETE 1 330 #define DM_ENDIO_REQUEUE 2 331 332 /* 333 * Definitions of return values from target map function. 334 */ 335 #define DM_MAPIO_SUBMITTED 0 336 #define DM_MAPIO_REMAPPED 1 337 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE 338 339 /* 340 * Ceiling(n / sz) 341 */ 342 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz)) 343 344 #define dm_sector_div_up(n, sz) ( \ 345 { \ 346 sector_t _r = ((n) + (sz) - 1); \ 347 sector_div(_r, (sz)); \ 348 _r; \ 349 } \ 350 ) 351 352 /* 353 * ceiling(n / size) * size 354 */ 355 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz)) 356 357 static inline sector_t to_sector(unsigned long n) 358 { 359 return (n >> SECTOR_SHIFT); 360 } 361 362 static inline unsigned long to_bytes(sector_t n) 363 { 364 return (n << SECTOR_SHIFT); 365 } 366 367 #endif /* _LINUX_DEVICE_MAPPER_H */ 368