Linux kernel mirror (for testing)
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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
8#ifndef _LINUX_DEVICE_MAPPER_H
9#define _LINUX_DEVICE_MAPPER_H
10
11#ifdef __KERNEL__
12
13struct dm_target;
14struct dm_table;
15struct dm_dev;
16struct mapped_device;
17
18typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
19
20union 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 */
29typedef 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 */
36typedef 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 */
44typedef 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 */
54typedef int (*dm_endio_fn) (struct dm_target *ti,
55 struct bio *bio, int error,
56 union map_info *map_context);
57
58typedef void (*dm_presuspend_fn) (struct dm_target *ti);
59typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
60typedef void (*dm_resume_fn) (struct dm_target *ti);
61
62typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
63 char *result, unsigned int maxlen);
64
65typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
66
67void 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 */
74int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
75 sector_t len, int mode, struct dm_dev **result);
76void dm_put_device(struct dm_target *ti, struct dm_dev *d);
77
78/*
79 * Information about a target type
80 */
81struct 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
96struct 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
106struct 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
131int dm_register_target(struct target_type *t);
132int 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)
144int dm_create(int minor, struct mapped_device **md);
145
146/*
147 * Reference counting for md.
148 */
149struct mapped_device *dm_get_md(dev_t dev);
150void dm_get(struct mapped_device *md);
151void dm_put(struct mapped_device *md);
152
153/*
154 * An arbitrary pointer may be stored alongside a mapped device.
155 */
156void dm_set_mdptr(struct mapped_device *md, void *ptr);
157void *dm_get_mdptr(struct mapped_device *md);
158
159/*
160 * A device can still be used while suspended, but I/O is deferred.
161 */
162int dm_suspend(struct mapped_device *md, int with_lockfs);
163int dm_resume(struct mapped_device *md);
164
165/*
166 * Event functions.
167 */
168uint32_t dm_get_event_nr(struct mapped_device *md);
169int dm_wait_event(struct mapped_device *md, int event_nr);
170
171/*
172 * Info functions.
173 */
174const char *dm_device_name(struct mapped_device *md);
175struct gendisk *dm_disk(struct mapped_device *md);
176int dm_suspended(struct mapped_device *md);
177
178/*
179 * Geometry functions.
180 */
181int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
182int 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 */
192int 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 */
198int 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 */
204int dm_table_complete(struct dm_table *t);
205
206/*
207 * Table reference counting.
208 */
209struct dm_table *dm_get_table(struct mapped_device *md);
210void dm_table_get(struct dm_table *t);
211void dm_table_put(struct dm_table *t);
212
213/*
214 * Queries
215 */
216sector_t dm_table_get_size(struct dm_table *t);
217unsigned int dm_table_get_num_targets(struct dm_table *t);
218int dm_table_get_mode(struct dm_table *t);
219struct mapped_device *dm_table_get_md(struct dm_table *t);
220
221/*
222 * Trigger an event.
223 */
224void dm_table_event(struct dm_table *t);
225
226/*
227 * The device must be suspended before calling this method.
228 */
229int 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 */
235int dm_create_error_table(struct dm_table **result, struct mapped_device *md);
236
237#endif /* __KERNEL__ */
238#endif /* _LINUX_DEVICE_MAPPER_H */