131 lines
3.2 KiB
C
131 lines
3.2 KiB
C
/*
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* Copyright (C) 2001 Sistina Software (UK) Limited.
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* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the LGPL.
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*/
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#ifndef _LINUX_DEVICE_MAPPER_H
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#define _LINUX_DEVICE_MAPPER_H
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struct dm_target;
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struct dm_table;
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struct dm_dev;
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typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
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union map_info {
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void *ptr;
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unsigned long long ll;
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};
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/*
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* In the constructor the target parameter will already have the
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* table, type, begin and len fields filled in.
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*/
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typedef int (*dm_ctr_fn) (struct dm_target *target,
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unsigned int argc, char **argv);
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/*
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* The destructor doesn't need to free the dm_target, just
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* anything hidden ti->private.
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*/
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typedef void (*dm_dtr_fn) (struct dm_target *ti);
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/*
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* The map function must return:
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* < 0: error
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* = 0: The target will handle the io by resubmitting it later
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* > 0: simple remap complete
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*/
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typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
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union map_info *map_context);
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/*
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* Returns:
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* < 0 : error (currently ignored)
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* 0 : ended successfully
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* 1 : for some reason the io has still not completed (eg,
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* multipath target might want to requeue a failed io).
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*/
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typedef int (*dm_endio_fn) (struct dm_target *ti,
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struct bio *bio, int error,
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union map_info *map_context);
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typedef void (*dm_presuspend_fn) (struct dm_target *ti);
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typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
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typedef void (*dm_resume_fn) (struct dm_target *ti);
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typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
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char *result, unsigned int maxlen);
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typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
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void dm_error(const char *message);
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/*
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* Constructors should call these functions to ensure destination devices
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* are opened/closed correctly.
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* FIXME: too many arguments.
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*/
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int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
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sector_t len, int mode, struct dm_dev **result);
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void dm_put_device(struct dm_target *ti, struct dm_dev *d);
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/*
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* Information about a target type
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*/
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struct target_type {
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const char *name;
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struct module *module;
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unsigned version[3];
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dm_ctr_fn ctr;
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dm_dtr_fn dtr;
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dm_map_fn map;
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dm_endio_fn end_io;
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dm_presuspend_fn presuspend;
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dm_postsuspend_fn postsuspend;
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dm_resume_fn resume;
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dm_status_fn status;
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dm_message_fn message;
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};
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struct io_restrictions {
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unsigned short max_sectors;
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unsigned short max_phys_segments;
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unsigned short max_hw_segments;
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unsigned short hardsect_size;
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unsigned int max_segment_size;
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unsigned long seg_boundary_mask;
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};
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struct dm_target {
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struct dm_table *table;
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struct target_type *type;
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/* target limits */
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sector_t begin;
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sector_t len;
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/* FIXME: turn this into a mask, and merge with io_restrictions */
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/* Always a power of 2 */
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sector_t split_io;
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/*
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* These are automatically filled in by
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* dm_table_get_device.
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*/
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struct io_restrictions limits;
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/* target specific data */
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void *private;
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/* Used to provide an error string from the ctr */
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char *error;
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};
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int dm_register_target(struct target_type *t);
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int dm_unregister_target(struct target_type *t);
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#endif /* _LINUX_DEVICE_MAPPER_H */
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