dm-btree-internal.h
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/*
* Copyright (C) 2011 Red Hat, Inc.
*
* This file is released under the GPL.
*/
#ifndef DM_BTREE_INTERNAL_H
#define DM_BTREE_INTERNAL_H
#include "dm-btree.h"
/*----------------------------------------------------------------*/
/*
* We'll need 2 accessor functions for n->csum and n->blocknr
* to support dm-btree-spine.c in that case.
*/
enum node_flags {
INTERNAL_NODE = 1,
LEAF_NODE = 1 << 1
};
/*
* Every btree node begins with this structure. Make sure it's a multiple
* of 8-bytes in size, otherwise the 64bit keys will be mis-aligned.
*/
struct node_header {
__le32 csum;
__le32 flags;
__le64 blocknr; /* Block this node is supposed to live in. */
__le32 nr_entries;
__le32 max_entries;
__le32 value_size;
__le32 padding;
} __packed;
struct btree_node {
struct node_header header;
__le64 keys[0];
} __packed;
/*
* Locks a block using the btree node validator.
*/
int bn_read_lock(struct dm_btree_info *info, dm_block_t b,
struct dm_block **result);
void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
struct dm_btree_value_type *vt);
int new_block(struct dm_btree_info *info, struct dm_block **result);
int unlock_block(struct dm_btree_info *info, struct dm_block *b);
/*
* Spines keep track of the rolling locks. There are 2 variants, read-only
* and one that uses shadowing. These are separate structs to allow the
* type checker to spot misuse, for example accidentally calling read_lock
* on a shadow spine.
*/
struct ro_spine {
struct dm_btree_info *info;
int count;
struct dm_block *nodes[2];
};
void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info);
int exit_ro_spine(struct ro_spine *s);
int ro_step(struct ro_spine *s, dm_block_t new_child);
void ro_pop(struct ro_spine *s);
struct btree_node *ro_node(struct ro_spine *s);
struct shadow_spine {
struct dm_btree_info *info;
int count;
struct dm_block *nodes[2];
dm_block_t root;
};
void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info);
int exit_shadow_spine(struct shadow_spine *s);
int shadow_step(struct shadow_spine *s, dm_block_t b,
struct dm_btree_value_type *vt);
/*
* The spine must have at least one entry before calling this.
*/
struct dm_block *shadow_current(struct shadow_spine *s);
/*
* The spine must have at least two entries before calling this.
*/
struct dm_block *shadow_parent(struct shadow_spine *s);
int shadow_has_parent(struct shadow_spine *s);
int shadow_root(struct shadow_spine *s);
/*
* Some inlines.
*/
static inline __le64 *key_ptr(struct btree_node *n, uint32_t index)
{
return n->keys + index;
}
static inline void *value_base(struct btree_node *n)
{
return &n->keys[le32_to_cpu(n->header.max_entries)];
}
static inline void *value_ptr(struct btree_node *n, uint32_t index)
{
uint32_t value_size = le32_to_cpu(n->header.value_size);
return value_base(n) + (value_size * index);
}
/*
* Assumes the values are suitably-aligned and converts to core format.
*/
static inline uint64_t value64(struct btree_node *n, uint32_t index)
{
__le64 *values_le = value_base(n);
return le64_to_cpu(values_le[index]);
}
/*
* Searching for a key within a single node.
*/
int lower_bound(struct btree_node *n, uint64_t key);
extern struct dm_block_validator btree_node_validator;
#endif /* DM_BTREE_INTERNAL_H */