device-mapper.h 6.4 KB

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  1. /*
  2. * Copyright (C) 2001 Sistina Software (UK) Limited.
  3. * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
  4. *
  5. * This file is released under the LGPL.
  6. */
  7. #ifndef _LINUX_DEVICE_MAPPER_H
  8. #define _LINUX_DEVICE_MAPPER_H
  9. #ifdef __KERNEL__
  10. struct dm_target;
  11. struct dm_table;
  12. struct dm_dev;
  13. struct mapped_device;
  14. typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
  15. union map_info {
  16. void *ptr;
  17. unsigned long long ll;
  18. };
  19. /*
  20. * In the constructor the target parameter will already have the
  21. * table, type, begin and len fields filled in.
  22. */
  23. typedef int (*dm_ctr_fn) (struct dm_target *target,
  24. unsigned int argc, char **argv);
  25. /*
  26. * The destructor doesn't need to free the dm_target, just
  27. * anything hidden ti->private.
  28. */
  29. typedef void (*dm_dtr_fn) (struct dm_target *ti);
  30. /*
  31. * The map function must return:
  32. * < 0: error
  33. * = 0: The target will handle the io by resubmitting it later
  34. * > 0: simple remap complete
  35. */
  36. typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
  37. union map_info *map_context);
  38. /*
  39. * Returns:
  40. * < 0 : error (currently ignored)
  41. * 0 : ended successfully
  42. * 1 : for some reason the io has still not completed (eg,
  43. * multipath target might want to requeue a failed io).
  44. */
  45. typedef int (*dm_endio_fn) (struct dm_target *ti,
  46. struct bio *bio, int error,
  47. union map_info *map_context);
  48. typedef void (*dm_presuspend_fn) (struct dm_target *ti);
  49. typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
  50. typedef int (*dm_preresume_fn) (struct dm_target *ti);
  51. typedef void (*dm_resume_fn) (struct dm_target *ti);
  52. typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
  53. char *result, unsigned int maxlen);
  54. typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
  55. typedef int (*dm_ioctl_fn) (struct dm_target *ti, struct inode *inode,
  56. struct file *filp, unsigned int cmd,
  57. unsigned long arg);
  58. void dm_error(const char *message);
  59. /*
  60. * Combine device limits.
  61. */
  62. void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev);
  63. /*
  64. * Constructors should call these functions to ensure destination devices
  65. * are opened/closed correctly.
  66. * FIXME: too many arguments.
  67. */
  68. int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
  69. sector_t len, int mode, struct dm_dev **result);
  70. void dm_put_device(struct dm_target *ti, struct dm_dev *d);
  71. /*
  72. * Information about a target type
  73. */
  74. struct target_type {
  75. const char *name;
  76. struct module *module;
  77. unsigned version[3];
  78. dm_ctr_fn ctr;
  79. dm_dtr_fn dtr;
  80. dm_map_fn map;
  81. dm_endio_fn end_io;
  82. dm_presuspend_fn presuspend;
  83. dm_postsuspend_fn postsuspend;
  84. dm_preresume_fn preresume;
  85. dm_resume_fn resume;
  86. dm_status_fn status;
  87. dm_message_fn message;
  88. dm_ioctl_fn ioctl;
  89. };
  90. struct io_restrictions {
  91. unsigned int max_sectors;
  92. unsigned short max_phys_segments;
  93. unsigned short max_hw_segments;
  94. unsigned short hardsect_size;
  95. unsigned int max_segment_size;
  96. unsigned long seg_boundary_mask;
  97. unsigned char no_cluster; /* inverted so that 0 is default */
  98. };
  99. struct dm_target {
  100. struct dm_table *table;
  101. struct target_type *type;
  102. /* target limits */
  103. sector_t begin;
  104. sector_t len;
  105. /* FIXME: turn this into a mask, and merge with io_restrictions */
  106. /* Always a power of 2 */
  107. sector_t split_io;
  108. /*
  109. * These are automatically filled in by
  110. * dm_table_get_device.
  111. */
  112. struct io_restrictions limits;
  113. /* target specific data */
  114. void *private;
  115. /* Used to provide an error string from the ctr */
  116. char *error;
  117. };
  118. int dm_register_target(struct target_type *t);
  119. int dm_unregister_target(struct target_type *t);
  120. /*-----------------------------------------------------------------
  121. * Functions for creating and manipulating mapped devices.
  122. * Drop the reference with dm_put when you finish with the object.
  123. *---------------------------------------------------------------*/
  124. /*
  125. * DM_ANY_MINOR chooses the next available minor number.
  126. */
  127. #define DM_ANY_MINOR (-1)
  128. int dm_create(int minor, struct mapped_device **md);
  129. /*
  130. * Reference counting for md.
  131. */
  132. struct mapped_device *dm_get_md(dev_t dev);
  133. void dm_get(struct mapped_device *md);
  134. void dm_put(struct mapped_device *md);
  135. /*
  136. * An arbitrary pointer may be stored alongside a mapped device.
  137. */
  138. void dm_set_mdptr(struct mapped_device *md, void *ptr);
  139. void *dm_get_mdptr(struct mapped_device *md);
  140. /*
  141. * A device can still be used while suspended, but I/O is deferred.
  142. */
  143. int dm_suspend(struct mapped_device *md, int with_lockfs);
  144. int dm_resume(struct mapped_device *md);
  145. /*
  146. * Event functions.
  147. */
  148. uint32_t dm_get_event_nr(struct mapped_device *md);
  149. int dm_wait_event(struct mapped_device *md, int event_nr);
  150. /*
  151. * Info functions.
  152. */
  153. const char *dm_device_name(struct mapped_device *md);
  154. struct gendisk *dm_disk(struct mapped_device *md);
  155. int dm_suspended(struct mapped_device *md);
  156. /*
  157. * Geometry functions.
  158. */
  159. int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
  160. int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
  161. /*-----------------------------------------------------------------
  162. * Functions for manipulating device-mapper tables.
  163. *---------------------------------------------------------------*/
  164. /*
  165. * First create an empty table.
  166. */
  167. int dm_table_create(struct dm_table **result, int mode,
  168. unsigned num_targets, struct mapped_device *md);
  169. /*
  170. * Then call this once for each target.
  171. */
  172. int dm_table_add_target(struct dm_table *t, const char *type,
  173. sector_t start, sector_t len, char *params);
  174. /*
  175. * Finally call this to make the table ready for use.
  176. */
  177. int dm_table_complete(struct dm_table *t);
  178. /*
  179. * Table reference counting.
  180. */
  181. struct dm_table *dm_get_table(struct mapped_device *md);
  182. void dm_table_get(struct dm_table *t);
  183. void dm_table_put(struct dm_table *t);
  184. /*
  185. * Queries
  186. */
  187. sector_t dm_table_get_size(struct dm_table *t);
  188. unsigned int dm_table_get_num_targets(struct dm_table *t);
  189. int dm_table_get_mode(struct dm_table *t);
  190. struct mapped_device *dm_table_get_md(struct dm_table *t);
  191. /*
  192. * Trigger an event.
  193. */
  194. void dm_table_event(struct dm_table *t);
  195. /*
  196. * The device must be suspended before calling this method.
  197. */
  198. int dm_swap_table(struct mapped_device *md, struct dm_table *t);
  199. /*
  200. * Prepare a table for a device that will error all I/O.
  201. * To make it active, call dm_suspend(), dm_swap_table() then dm_resume().
  202. */
  203. int dm_create_error_table(struct dm_table **result, struct mapped_device *md);
  204. #endif /* __KERNEL__ */
  205. #endif /* _LINUX_DEVICE_MAPPER_H */