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