1/*
2 * Copyright (C) 2011 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7#ifndef DM_BTREE_INTERNAL_H
8#define DM_BTREE_INTERNAL_H
9
10#include "dm-btree.h"
11
12/*----------------------------------------------------------------*/
13
14/*
15 * We'll need 2 accessor functions for n->csum and n->blocknr
16 * to support dm-btree-spine.c in that case.
17 */
18
19enum node_flags {
20	INTERNAL_NODE = 1,
21	LEAF_NODE = 1 << 1
22};
23
24/*
25 * Every btree node begins with this structure.  Make sure it's a multiple
26 * of 8-bytes in size, otherwise the 64bit keys will be mis-aligned.
27 */
28struct node_header {
29	__le32 csum;
30	__le32 flags;
31	__le64 blocknr; /* Block this node is supposed to live in. */
32
33	__le32 nr_entries;
34	__le32 max_entries;
35	__le32 value_size;
36	__le32 padding;
37} __packed;
38
39struct btree_node {
40	struct node_header header;
41	__le64 keys[0];
42} __packed;
43
44
45/*
46 * Locks a block using the btree node validator.
47 */
48int bn_read_lock(struct dm_btree_info *info, dm_block_t b,
49		 struct dm_block **result);
50
51void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
52		  struct dm_btree_value_type *vt);
53
54int new_block(struct dm_btree_info *info, struct dm_block **result);
55int unlock_block(struct dm_btree_info *info, struct dm_block *b);
56
57/*
58 * Spines keep track of the rolling locks.  There are 2 variants, read-only
59 * and one that uses shadowing.  These are separate structs to allow the
60 * type checker to spot misuse, for example accidentally calling read_lock
61 * on a shadow spine.
62 */
63struct ro_spine {
64	struct dm_btree_info *info;
65
66	int count;
67	struct dm_block *nodes[2];
68};
69
70void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info);
71int exit_ro_spine(struct ro_spine *s);
72int ro_step(struct ro_spine *s, dm_block_t new_child);
73void ro_pop(struct ro_spine *s);
74struct btree_node *ro_node(struct ro_spine *s);
75
76struct shadow_spine {
77	struct dm_btree_info *info;
78
79	int count;
80	struct dm_block *nodes[2];
81
82	dm_block_t root;
83};
84
85void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info);
86int exit_shadow_spine(struct shadow_spine *s);
87
88int shadow_step(struct shadow_spine *s, dm_block_t b,
89		struct dm_btree_value_type *vt);
90
91/*
92 * The spine must have at least one entry before calling this.
93 */
94struct dm_block *shadow_current(struct shadow_spine *s);
95
96/*
97 * The spine must have at least two entries before calling this.
98 */
99struct dm_block *shadow_parent(struct shadow_spine *s);
100
101int shadow_has_parent(struct shadow_spine *s);
102
103int shadow_root(struct shadow_spine *s);
104
105/*
106 * Some inlines.
107 */
108static inline __le64 *key_ptr(struct btree_node *n, uint32_t index)
109{
110	return n->keys + index;
111}
112
113static inline void *value_base(struct btree_node *n)
114{
115	return &n->keys[le32_to_cpu(n->header.max_entries)];
116}
117
118static inline void *value_ptr(struct btree_node *n, uint32_t index)
119{
120	uint32_t value_size = le32_to_cpu(n->header.value_size);
121	return value_base(n) + (value_size * index);
122}
123
124/*
125 * Assumes the values are suitably-aligned and converts to core format.
126 */
127static inline uint64_t value64(struct btree_node *n, uint32_t index)
128{
129	__le64 *values_le = value_base(n);
130
131	return le64_to_cpu(values_le[index]);
132}
133
134/*
135 * Searching for a key within a single node.
136 */
137int lower_bound(struct btree_node *n, uint64_t key);
138
139extern struct dm_block_validator btree_node_validator;
140
141/*
142 * Value type for upper levels of multi-level btrees.
143 */
144extern void init_le64_type(struct dm_transaction_manager *tm,
145			   struct dm_btree_value_type *vt);
146
147#endif	/* DM_BTREE_INTERNAL_H */
148