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 * = 1: simple remap complete 43 * = 2: The target wants to push back the io 44 */ 45 typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio, 46 union map_info *map_context); 47 48 /* 49 * Returns: 50 * < 0 : error (currently ignored) 51 * 0 : ended successfully 52 * 1 : for some reason the io has still not completed (eg, 53 * multipath target might want to requeue a failed io). 54 * 2 : The target wants to push back the io 55 */ 56 typedef int (*dm_endio_fn) (struct dm_target *ti, 57 struct bio *bio, int error, 58 union map_info *map_context); 59 60 typedef void (*dm_flush_fn) (struct dm_target *ti); 61 typedef void (*dm_presuspend_fn) (struct dm_target *ti); 62 typedef void (*dm_postsuspend_fn) (struct dm_target *ti); 63 typedef int (*dm_preresume_fn) (struct dm_target *ti); 64 typedef void (*dm_resume_fn) (struct dm_target *ti); 65 66 typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type, 67 char *result, unsigned int maxlen); 68 69 typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv); 70 71 typedef int (*dm_ioctl_fn) (struct dm_target *ti, struct inode *inode, 72 struct file *filp, unsigned int cmd, 73 unsigned long arg); 74 75 void dm_error(const char *message); 76 77 /* 78 * Combine device limits. 79 */ 80 void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev); 81 82 /* 83 * Constructors should call these functions to ensure destination devices 84 * are opened/closed correctly. 85 * FIXME: too many arguments. 86 */ 87 int dm_get_device(struct dm_target *ti, const char *path, sector_t start, 88 sector_t len, int mode, struct dm_dev **result); 89 void dm_put_device(struct dm_target *ti, struct dm_dev *d); 90 91 /* 92 * Information about a target type 93 */ 94 struct target_type { 95 const char *name; 96 struct module *module; 97 unsigned version[3]; 98 dm_ctr_fn ctr; 99 dm_dtr_fn dtr; 100 dm_map_fn map; 101 dm_endio_fn end_io; 102 dm_flush_fn flush; 103 dm_presuspend_fn presuspend; 104 dm_postsuspend_fn postsuspend; 105 dm_preresume_fn preresume; 106 dm_resume_fn resume; 107 dm_status_fn status; 108 dm_message_fn message; 109 dm_ioctl_fn ioctl; 110 }; 111 112 struct io_restrictions { 113 unsigned int max_sectors; 114 unsigned short max_phys_segments; 115 unsigned short max_hw_segments; 116 unsigned short hardsect_size; 117 unsigned int max_segment_size; 118 unsigned int max_hw_sectors; 119 unsigned long seg_boundary_mask; 120 unsigned long bounce_pfn; 121 unsigned char no_cluster; /* inverted so that 0 is default */ 122 }; 123 124 struct dm_target { 125 struct dm_table *table; 126 struct target_type *type; 127 128 /* target limits */ 129 sector_t begin; 130 sector_t len; 131 132 /* FIXME: turn this into a mask, and merge with io_restrictions */ 133 /* Always a power of 2 */ 134 sector_t split_io; 135 136 /* 137 * These are automatically filled in by 138 * dm_table_get_device. 139 */ 140 struct io_restrictions limits; 141 142 /* target specific data */ 143 void *private; 144 145 /* Used to provide an error string from the ctr */ 146 char *error; 147 }; 148 149 int dm_register_target(struct target_type *t); 150 int dm_unregister_target(struct target_type *t); 151 152 153 /*----------------------------------------------------------------- 154 * Functions for creating and manipulating mapped devices. 155 * Drop the reference with dm_put when you finish with the object. 156 *---------------------------------------------------------------*/ 157 158 /* 159 * DM_ANY_MINOR chooses the next available minor number. 160 */ 161 #define DM_ANY_MINOR (-1) 162 int dm_create(int minor, struct mapped_device **md); 163 164 /* 165 * Reference counting for md. 166 */ 167 struct mapped_device *dm_get_md(dev_t dev); 168 void dm_get(struct mapped_device *md); 169 void dm_put(struct mapped_device *md); 170 171 /* 172 * An arbitrary pointer may be stored alongside a mapped device. 173 */ 174 void dm_set_mdptr(struct mapped_device *md, void *ptr); 175 void *dm_get_mdptr(struct mapped_device *md); 176 177 /* 178 * A device can still be used while suspended, but I/O is deferred. 179 */ 180 int dm_suspend(struct mapped_device *md, unsigned suspend_flags); 181 int dm_resume(struct mapped_device *md); 182 183 /* 184 * Event functions. 185 */ 186 uint32_t dm_get_event_nr(struct mapped_device *md); 187 int dm_wait_event(struct mapped_device *md, int event_nr); 188 uint32_t dm_next_uevent_seq(struct mapped_device *md); 189 void dm_uevent_add(struct mapped_device *md, struct list_head *elist); 190 191 /* 192 * Info functions. 193 */ 194 const char *dm_device_name(struct mapped_device *md); 195 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid); 196 struct gendisk *dm_disk(struct mapped_device *md); 197 int dm_suspended(struct mapped_device *md); 198 int dm_noflush_suspending(struct dm_target *ti); 199 200 /* 201 * Geometry functions. 202 */ 203 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo); 204 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo); 205 206 207 /*----------------------------------------------------------------- 208 * Functions for manipulating device-mapper tables. 209 *---------------------------------------------------------------*/ 210 211 /* 212 * First create an empty table. 213 */ 214 int dm_table_create(struct dm_table **result, int mode, 215 unsigned num_targets, struct mapped_device *md); 216 217 /* 218 * Then call this once for each target. 219 */ 220 int dm_table_add_target(struct dm_table *t, const char *type, 221 sector_t start, sector_t len, char *params); 222 223 /* 224 * Finally call this to make the table ready for use. 225 */ 226 int dm_table_complete(struct dm_table *t); 227 228 /* 229 * Table reference counting. 230 */ 231 struct dm_table *dm_get_table(struct mapped_device *md); 232 void dm_table_get(struct dm_table *t); 233 void dm_table_put(struct dm_table *t); 234 235 /* 236 * Queries 237 */ 238 sector_t dm_table_get_size(struct dm_table *t); 239 unsigned int dm_table_get_num_targets(struct dm_table *t); 240 int dm_table_get_mode(struct dm_table *t); 241 struct mapped_device *dm_table_get_md(struct dm_table *t); 242 243 /* 244 * Trigger an event. 245 */ 246 void dm_table_event(struct dm_table *t); 247 248 /* 249 * The device must be suspended before calling this method. 250 */ 251 int dm_swap_table(struct mapped_device *md, struct dm_table *t); 252 253 /* 254 * Prepare a table for a device that will error all I/O. 255 * To make it active, call dm_suspend(), dm_swap_table() then dm_resume(). 256 */ 257 int dm_create_error_table(struct dm_table **result, struct mapped_device *md); 258 259 #endif /* __KERNEL__ */ 260 #endif /* _LINUX_DEVICE_MAPPER_H */ 261