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 
19 enum 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  */
28 struct 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 
39 struct btree_node {
40 	struct node_header header;
41 	__le64 keys[0];
42 } __packed;
43 
44 
45 void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
46 		  struct dm_btree_value_type *vt);
47 
48 int new_block(struct dm_btree_info *info, struct dm_block **result);
49 int unlock_block(struct dm_btree_info *info, struct dm_block *b);
50 
51 /*
52  * Spines keep track of the rolling locks.  There are 2 variants, read-only
53  * and one that uses shadowing.  These are separate structs to allow the
54  * type checker to spot misuse, for example accidentally calling read_lock
55  * on a shadow spine.
56  */
57 struct ro_spine {
58 	struct dm_btree_info *info;
59 
60 	int count;
61 	struct dm_block *nodes[2];
62 };
63 
64 void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info);
65 int exit_ro_spine(struct ro_spine *s);
66 int ro_step(struct ro_spine *s, dm_block_t new_child);
67 void ro_pop(struct ro_spine *s);
68 struct btree_node *ro_node(struct ro_spine *s);
69 
70 struct shadow_spine {
71 	struct dm_btree_info *info;
72 
73 	int count;
74 	struct dm_block *nodes[2];
75 
76 	dm_block_t root;
77 };
78 
79 void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info);
80 int exit_shadow_spine(struct shadow_spine *s);
81 
82 int shadow_step(struct shadow_spine *s, dm_block_t b,
83 		struct dm_btree_value_type *vt);
84 
85 /*
86  * The spine must have at least one entry before calling this.
87  */
88 struct dm_block *shadow_current(struct shadow_spine *s);
89 
90 /*
91  * The spine must have at least two entries before calling this.
92  */
93 struct dm_block *shadow_parent(struct shadow_spine *s);
94 
95 int shadow_has_parent(struct shadow_spine *s);
96 
97 int shadow_root(struct shadow_spine *s);
98 
99 /*
100  * Some inlines.
101  */
102 static inline __le64 *key_ptr(struct btree_node *n, uint32_t index)
103 {
104 	return n->keys + index;
105 }
106 
107 static inline void *value_base(struct btree_node *n)
108 {
109 	return &n->keys[le32_to_cpu(n->header.max_entries)];
110 }
111 
112 static inline void *value_ptr(struct btree_node *n, uint32_t index)
113 {
114 	uint32_t value_size = le32_to_cpu(n->header.value_size);
115 	return value_base(n) + (value_size * index);
116 }
117 
118 /*
119  * Assumes the values are suitably-aligned and converts to core format.
120  */
121 static inline uint64_t value64(struct btree_node *n, uint32_t index)
122 {
123 	__le64 *values_le = value_base(n);
124 
125 	return le64_to_cpu(values_le[index]);
126 }
127 
128 /*
129  * Searching for a key within a single node.
130  */
131 int lower_bound(struct btree_node *n, uint64_t key);
132 
133 extern struct dm_block_validator btree_node_validator;
134 
135 #endif	/* DM_BTREE_INTERNAL_H */
136