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 8 #ifndef _LINUX_DEVICE_MAPPER_H 9 #define _LINUX_DEVICE_MAPPER_H 10 11 #ifdef __KERNEL__ 12 13 struct dm_target; 14 struct dm_table; 15 struct dm_dev; 16 struct mapped_device; 17 18 typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t; 19 20 union map_info { 21 void *ptr; 22 unsigned long long ll; 23 }; 24 25 /* 26 * In the constructor the target parameter will already have the 27 * table, type, begin and len fields filled in. 28 */ 29 typedef int (*dm_ctr_fn) (struct dm_target *target, 30 unsigned int argc, char **argv); 31 32 /* 33 * The destructor doesn't need to free the dm_target, just 34 * anything hidden ti->private. 35 */ 36 typedef void (*dm_dtr_fn) (struct dm_target *ti); 37 38 /* 39 * The map function must return: 40 * < 0: error 41 * = 0: The target will handle the io by resubmitting it later 42 * > 0: simple remap complete 43 */ 44 typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio, 45 union map_info *map_context); 46 47 /* 48 * Returns: 49 * < 0 : error (currently ignored) 50 * 0 : ended successfully 51 * 1 : for some reason the io has still not completed (eg, 52 * multipath target might want to requeue a failed io). 53 */ 54 typedef int (*dm_endio_fn) (struct dm_target *ti, 55 struct bio *bio, int error, 56 union map_info *map_context); 57 58 typedef void (*dm_presuspend_fn) (struct dm_target *ti); 59 typedef void (*dm_postsuspend_fn) (struct dm_target *ti); 60 typedef void (*dm_resume_fn) (struct dm_target *ti); 61 62 typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type, 63 char *result, unsigned int maxlen); 64 65 typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv); 66 67 void dm_error(const char *message); 68 69 /* 70 * Constructors should call these functions to ensure destination devices 71 * are opened/closed correctly. 72 * FIXME: too many arguments. 73 */ 74 int dm_get_device(struct dm_target *ti, const char *path, sector_t start, 75 sector_t len, int mode, struct dm_dev **result); 76 void dm_put_device(struct dm_target *ti, struct dm_dev *d); 77 78 /* 79 * Information about a target type 80 */ 81 struct target_type { 82 const char *name; 83 struct module *module; 84 unsigned version[3]; 85 dm_ctr_fn ctr; 86 dm_dtr_fn dtr; 87 dm_map_fn map; 88 dm_endio_fn end_io; 89 dm_presuspend_fn presuspend; 90 dm_postsuspend_fn postsuspend; 91 dm_resume_fn resume; 92 dm_status_fn status; 93 dm_message_fn message; 94 }; 95 96 struct io_restrictions { 97 unsigned int max_sectors; 98 unsigned short max_phys_segments; 99 unsigned short max_hw_segments; 100 unsigned short hardsect_size; 101 unsigned int max_segment_size; 102 unsigned long seg_boundary_mask; 103 unsigned char no_cluster; /* inverted so that 0 is default */ 104 }; 105 106 struct dm_target { 107 struct dm_table *table; 108 struct target_type *type; 109 110 /* target limits */ 111 sector_t begin; 112 sector_t len; 113 114 /* FIXME: turn this into a mask, and merge with io_restrictions */ 115 /* Always a power of 2 */ 116 sector_t split_io; 117 118 /* 119 * These are automatically filled in by 120 * dm_table_get_device. 121 */ 122 struct io_restrictions limits; 123 124 /* target specific data */ 125 void *private; 126 127 /* Used to provide an error string from the ctr */ 128 char *error; 129 }; 130 131 int dm_register_target(struct target_type *t); 132 int dm_unregister_target(struct target_type *t); 133 134 135 /*----------------------------------------------------------------- 136 * Functions for creating and manipulating mapped devices. 137 * Drop the reference with dm_put when you finish with the object. 138 *---------------------------------------------------------------*/ 139 140 /* 141 * DM_ANY_MINOR chooses the next available minor number. 142 */ 143 #define DM_ANY_MINOR (-1) 144 int dm_create(int minor, struct mapped_device **md); 145 146 /* 147 * Reference counting for md. 148 */ 149 struct mapped_device *dm_get_md(dev_t dev); 150 void dm_get(struct mapped_device *md); 151 void dm_put(struct mapped_device *md); 152 153 /* 154 * An arbitrary pointer may be stored alongside a mapped device. 155 */ 156 void dm_set_mdptr(struct mapped_device *md, void *ptr); 157 void *dm_get_mdptr(struct mapped_device *md); 158 159 /* 160 * A device can still be used while suspended, but I/O is deferred. 161 */ 162 int dm_suspend(struct mapped_device *md, int with_lockfs); 163 int dm_resume(struct mapped_device *md); 164 165 /* 166 * Event functions. 167 */ 168 uint32_t dm_get_event_nr(struct mapped_device *md); 169 int dm_wait_event(struct mapped_device *md, int event_nr); 170 171 /* 172 * Info functions. 173 */ 174 const char *dm_device_name(struct mapped_device *md); 175 struct gendisk *dm_disk(struct mapped_device *md); 176 int dm_suspended(struct mapped_device *md); 177 178 /* 179 * Geometry functions. 180 */ 181 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo); 182 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo); 183 184 185 /*----------------------------------------------------------------- 186 * Functions for manipulating device-mapper tables. 187 *---------------------------------------------------------------*/ 188 189 /* 190 * First create an empty table. 191 */ 192 int dm_table_create(struct dm_table **result, int mode, 193 unsigned num_targets, struct mapped_device *md); 194 195 /* 196 * Then call this once for each target. 197 */ 198 int dm_table_add_target(struct dm_table *t, const char *type, 199 sector_t start, sector_t len, char *params); 200 201 /* 202 * Finally call this to make the table ready for use. 203 */ 204 int dm_table_complete(struct dm_table *t); 205 206 /* 207 * Table reference counting. 208 */ 209 struct dm_table *dm_get_table(struct mapped_device *md); 210 void dm_table_get(struct dm_table *t); 211 void dm_table_put(struct dm_table *t); 212 213 /* 214 * Queries 215 */ 216 sector_t dm_table_get_size(struct dm_table *t); 217 unsigned int dm_table_get_num_targets(struct dm_table *t); 218 int dm_table_get_mode(struct dm_table *t); 219 struct mapped_device *dm_table_get_md(struct dm_table *t); 220 221 /* 222 * Trigger an event. 223 */ 224 void dm_table_event(struct dm_table *t); 225 226 /* 227 * The device must be suspended before calling this method. 228 */ 229 int dm_swap_table(struct mapped_device *md, struct dm_table *t); 230 231 /* 232 * Prepare a table for a device that will error all I/O. 233 * To make it active, call dm_suspend(), dm_swap_table() then dm_resume(). 234 */ 235 int dm_create_error_table(struct dm_table **result, struct mapped_device *md); 236 237 #endif /* __KERNEL__ */ 238 #endif /* _LINUX_DEVICE_MAPPER_H */ 239