include/linux/device-mapper.h

   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 */