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, 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 */