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6
7#include "dm-btree-internal.h"
8#include "dm-transaction-manager.h"
9
10#include <linux/device-mapper.h>
11
12#define DM_MSG_PREFIX "btree spine"
13
14
15
16#define BTREE_CSUM_XOR 121107
17
18static int node_check(struct dm_block_validator *v,
19 struct dm_block *b,
20 size_t block_size);
21
22static void node_prepare_for_write(struct dm_block_validator *v,
23 struct dm_block *b,
24 size_t block_size)
25{
26 struct btree_node *n = dm_block_data(b);
27 struct node_header *h = &n->header;
28
29 h->blocknr = cpu_to_le64(dm_block_location(b));
30 h->csum = cpu_to_le32(dm_bm_checksum(&h->flags,
31 block_size - sizeof(__le32),
32 BTREE_CSUM_XOR));
33
34 BUG_ON(node_check(v, b, 4096));
35}
36
37static int node_check(struct dm_block_validator *v,
38 struct dm_block *b,
39 size_t block_size)
40{
41 struct btree_node *n = dm_block_data(b);
42 struct node_header *h = &n->header;
43 size_t value_size;
44 __le32 csum_disk;
45 uint32_t flags;
46
47 if (dm_block_location(b) != le64_to_cpu(h->blocknr)) {
48 DMERR_LIMIT("node_check failed: blocknr %llu != wanted %llu",
49 le64_to_cpu(h->blocknr), dm_block_location(b));
50 return -ENOTBLK;
51 }
52
53 csum_disk = cpu_to_le32(dm_bm_checksum(&h->flags,
54 block_size - sizeof(__le32),
55 BTREE_CSUM_XOR));
56 if (csum_disk != h->csum) {
57 DMERR_LIMIT("node_check failed: csum %u != wanted %u",
58 le32_to_cpu(csum_disk), le32_to_cpu(h->csum));
59 return -EILSEQ;
60 }
61
62 value_size = le32_to_cpu(h->value_size);
63
64 if (sizeof(struct node_header) +
65 (sizeof(__le64) + value_size) * le32_to_cpu(h->max_entries) > block_size) {
66 DMERR_LIMIT("node_check failed: max_entries too large");
67 return -EILSEQ;
68 }
69
70 if (le32_to_cpu(h->nr_entries) > le32_to_cpu(h->max_entries)) {
71 DMERR_LIMIT("node_check failed: too many entries");
72 return -EILSEQ;
73 }
74
75
76
77
78 flags = le32_to_cpu(h->flags);
79 if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) {
80 DMERR_LIMIT("node_check failed: node is neither INTERNAL or LEAF");
81 return -EILSEQ;
82 }
83
84 return 0;
85}
86
87struct dm_block_validator btree_node_validator = {
88 .name = "btree_node",
89 .prepare_for_write = node_prepare_for_write,
90 .check = node_check
91};
92
93
94
95static int bn_read_lock(struct dm_btree_info *info, dm_block_t b,
96 struct dm_block **result)
97{
98 return dm_tm_read_lock(info->tm, b, &btree_node_validator, result);
99}
100
101static int bn_shadow(struct dm_btree_info *info, dm_block_t orig,
102 struct dm_btree_value_type *vt,
103 struct dm_block **result)
104{
105 int r, inc;
106
107 r = dm_tm_shadow_block(info->tm, orig, &btree_node_validator,
108 result, &inc);
109 if (!r && inc)
110 inc_children(info->tm, dm_block_data(*result), vt);
111
112 return r;
113}
114
115int new_block(struct dm_btree_info *info, struct dm_block **result)
116{
117 return dm_tm_new_block(info->tm, &btree_node_validator, result);
118}
119
120int unlock_block(struct dm_btree_info *info, struct dm_block *b)
121{
122 return dm_tm_unlock(info->tm, b);
123}
124
125
126
127void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info)
128{
129 s->info = info;
130 s->count = 0;
131 s->nodes[0] = NULL;
132 s->nodes[1] = NULL;
133}
134
135int exit_ro_spine(struct ro_spine *s)
136{
137 int r = 0, i;
138
139 for (i = 0; i < s->count; i++) {
140 int r2 = unlock_block(s->info, s->nodes[i]);
141 if (r2 < 0)
142 r = r2;
143 }
144
145 return r;
146}
147
148int ro_step(struct ro_spine *s, dm_block_t new_child)
149{
150 int r;
151
152 if (s->count == 2) {
153 r = unlock_block(s->info, s->nodes[0]);
154 if (r < 0)
155 return r;
156 s->nodes[0] = s->nodes[1];
157 s->count--;
158 }
159
160 r = bn_read_lock(s->info, new_child, s->nodes + s->count);
161 if (!r)
162 s->count++;
163
164 return r;
165}
166
167void ro_pop(struct ro_spine *s)
168{
169 BUG_ON(!s->count);
170 --s->count;
171 unlock_block(s->info, s->nodes[s->count]);
172}
173
174struct btree_node *ro_node(struct ro_spine *s)
175{
176 struct dm_block *block;
177
178 BUG_ON(!s->count);
179 block = s->nodes[s->count - 1];
180
181 return dm_block_data(block);
182}
183
184
185
186void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info)
187{
188 s->info = info;
189 s->count = 0;
190}
191
192int exit_shadow_spine(struct shadow_spine *s)
193{
194 int r = 0, i;
195
196 for (i = 0; i < s->count; i++) {
197 int r2 = unlock_block(s->info, s->nodes[i]);
198 if (r2 < 0)
199 r = r2;
200 }
201
202 return r;
203}
204
205int shadow_step(struct shadow_spine *s, dm_block_t b,
206 struct dm_btree_value_type *vt)
207{
208 int r;
209
210 if (s->count == 2) {
211 r = unlock_block(s->info, s->nodes[0]);
212 if (r < 0)
213 return r;
214 s->nodes[0] = s->nodes[1];
215 s->count--;
216 }
217
218 r = bn_shadow(s->info, b, vt, s->nodes + s->count);
219 if (!r) {
220 if (!s->count)
221 s->root = dm_block_location(s->nodes[0]);
222
223 s->count++;
224 }
225
226 return r;
227}
228
229struct dm_block *shadow_current(struct shadow_spine *s)
230{
231 BUG_ON(!s->count);
232
233 return s->nodes[s->count - 1];
234}
235
236struct dm_block *shadow_parent(struct shadow_spine *s)
237{
238 BUG_ON(s->count != 2);
239
240 return s->count == 2 ? s->nodes[0] : NULL;
241}
242
243int shadow_has_parent(struct shadow_spine *s)
244{
245 return s->count >= 2;
246}
247
248int shadow_root(struct shadow_spine *s)
249{
250 return s->root;
251}
252
