dm-space-map.h
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/*
* Copyright (C) 2011 Red Hat, Inc.
*
* This file is released under the GPL.
*/
#ifndef _LINUX_DM_SPACE_MAP_H
#define _LINUX_DM_SPACE_MAP_H
#include "dm-block-manager.h"
typedef void (*dm_sm_threshold_fn)(void *context);
/*
* struct dm_space_map keeps a record of how many times each block in a device
* is referenced. It needs to be fixed on disk as part of the transaction.
*/
struct dm_space_map {
void (*destroy)(struct dm_space_map *sm);
/*
* You must commit before allocating the newly added space.
*/
int (*extend)(struct dm_space_map *sm, dm_block_t extra_blocks);
/*
* Extensions do not appear in this count until after commit has
* been called.
*/
int (*get_nr_blocks)(struct dm_space_map *sm, dm_block_t *count);
/*
* Space maps must never allocate a block from the previous
* transaction, in case we need to rollback. This complicates the
* semantics of get_nr_free(), it should return the number of blocks
* that are available for allocation _now_. For instance you may
* have blocks with a zero reference count that will not be
* available for allocation until after the next commit.
*/
int (*get_nr_free)(struct dm_space_map *sm, dm_block_t *count);
int (*get_count)(struct dm_space_map *sm, dm_block_t b, uint32_t *result);
int (*count_is_more_than_one)(struct dm_space_map *sm, dm_block_t b,
int *result);
int (*set_count)(struct dm_space_map *sm, dm_block_t b, uint32_t count);
int (*commit)(struct dm_space_map *sm);
int (*inc_block)(struct dm_space_map *sm, dm_block_t b);
int (*dec_block)(struct dm_space_map *sm, dm_block_t b);
/*
* new_block will increment the returned block.
*/
int (*new_block)(struct dm_space_map *sm, dm_block_t *b);
/*
* The root contains all the information needed to fix the space map.
* Generally this info is small, so squirrel it away in a disk block
* along with other info.
*/
int (*root_size)(struct dm_space_map *sm, size_t *result);
int (*copy_root)(struct dm_space_map *sm, void *copy_to_here_le, size_t len);
/*
* You can register one threshold callback which is edge-triggered
* when the free space in the space map drops below the threshold.
*/
int (*register_threshold_callback)(struct dm_space_map *sm,
dm_block_t threshold,
dm_sm_threshold_fn fn,
void *context);
};
/*----------------------------------------------------------------*/
static inline void dm_sm_destroy(struct dm_space_map *sm)
{
sm->destroy(sm);
}
static inline int dm_sm_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
{
return sm->extend(sm, extra_blocks);
}
static inline int dm_sm_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
{
return sm->get_nr_blocks(sm, count);
}
static inline int dm_sm_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
{
return sm->get_nr_free(sm, count);
}
static inline int dm_sm_get_count(struct dm_space_map *sm, dm_block_t b,
uint32_t *result)
{
return sm->get_count(sm, b, result);
}
static inline int dm_sm_count_is_more_than_one(struct dm_space_map *sm,
dm_block_t b, int *result)
{
return sm->count_is_more_than_one(sm, b, result);
}
static inline int dm_sm_set_count(struct dm_space_map *sm, dm_block_t b,
uint32_t count)
{
return sm->set_count(sm, b, count);
}
static inline int dm_sm_commit(struct dm_space_map *sm)
{
return sm->commit(sm);
}
static inline int dm_sm_inc_block(struct dm_space_map *sm, dm_block_t b)
{
return sm->inc_block(sm, b);
}
static inline int dm_sm_dec_block(struct dm_space_map *sm, dm_block_t b)
{
return sm->dec_block(sm, b);
}
static inline int dm_sm_new_block(struct dm_space_map *sm, dm_block_t *b)
{
return sm->new_block(sm, b);
}
static inline int dm_sm_root_size(struct dm_space_map *sm, size_t *result)
{
return sm->root_size(sm, result);
}
static inline int dm_sm_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len)
{
return sm->copy_root(sm, copy_to_here_le, len);
}
static inline int dm_sm_register_threshold_callback(struct dm_space_map *sm,
dm_block_t threshold,
dm_sm_threshold_fn fn,
void *context)
{
if (sm->register_threshold_callback)
return sm->register_threshold_callback(sm, threshold, fn, context);
return -EINVAL;
}
#endif /* _LINUX_DM_SPACE_MAP_H */