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 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 */