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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 void node_prepare_for_write(struct dm_block_validator *v,
19 struct dm_block *b,
20 size_t block_size)
21{
22 struct btree_node *n = dm_block_data(b);
23 struct node_header *h = &n->header;
24
25 h->blocknr = cpu_to_le64(dm_block_location(b));
26 h->csum = cpu_to_le32(dm_bm_checksum(&h->flags,
27 block_size - sizeof(__le32),
28 BTREE_CSUM_XOR));
29}
30
31static int node_check(struct dm_block_validator *v,
32 struct dm_block *b,
33 size_t block_size)
34{
35 struct btree_node *n = dm_block_data(b);
36 struct node_header *h = &n->header;
37 size_t value_size;
38 __le32 csum_disk;
39 uint32_t flags, nr_entries, max_entries;
40
41 if (dm_block_location(b) != le64_to_cpu(h->blocknr)) {
42 DMERR_LIMIT("node_check failed: blocknr %llu != wanted %llu",
43 le64_to_cpu(h->blocknr), dm_block_location(b));
44 return -ENOTBLK;
45 }
46
47 csum_disk = cpu_to_le32(dm_bm_checksum(&h->flags,
48 block_size - sizeof(__le32),
49 BTREE_CSUM_XOR));
50 if (csum_disk != h->csum) {
51 DMERR_LIMIT("node_check failed: csum %u != wanted %u",
52 le32_to_cpu(csum_disk), le32_to_cpu(h->csum));
53 return -EILSEQ;
54 }
55
56 nr_entries = le32_to_cpu(h->nr_entries);
57 max_entries = le32_to_cpu(h->max_entries);
58 value_size = le32_to_cpu(h->value_size);
59
60 if (sizeof(struct node_header) +
61 (sizeof(__le64) + value_size) * max_entries > block_size) {
62 DMERR_LIMIT("node_check failed: max_entries too large");
63 return -EILSEQ;
64 }
65
66 if (nr_entries > max_entries) {
67 DMERR_LIMIT("node_check failed: too many entries");
68 return -EILSEQ;
69 }
70
71
72
73
74 flags = le32_to_cpu(h->flags);
75 if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) {
76 DMERR_LIMIT("node_check failed: node is neither INTERNAL or LEAF");
77 return -EILSEQ;
78 }
79
80 return 0;
81}
82
83struct dm_block_validator btree_node_validator = {
84 .name = "btree_node",
85 .prepare_for_write = node_prepare_for_write,
86 .check = node_check
87};
88
89
90
91int bn_read_lock(struct dm_btree_info *info, dm_block_t b,
92 struct dm_block **result)
93{
94 return dm_tm_read_lock(info->tm, b, &btree_node_validator, result);
95}
96
97static int bn_shadow(struct dm_btree_info *info, dm_block_t orig,
98 struct dm_btree_value_type *vt,
99 struct dm_block **result)
100{
101 int r, inc;
102
103 r = dm_tm_shadow_block(info->tm, orig, &btree_node_validator,
104 result, &inc);
105 if (!r && inc)
106 inc_children(info->tm, dm_block_data(*result), vt);
107
108 return r;
109}
110
111int new_block(struct dm_btree_info *info, struct dm_block **result)
112{
113 return dm_tm_new_block(info->tm, &btree_node_validator, result);
114}
115
116void unlock_block(struct dm_btree_info *info, struct dm_block *b)
117{
118 dm_tm_unlock(info->tm, b);
119}
120
121
122
123void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info)
124{
125 s->info = info;
126 s->count = 0;
127 s->nodes[0] = NULL;
128 s->nodes[1] = NULL;
129}
130
131void exit_ro_spine(struct ro_spine *s)
132{
133 int i;
134
135 for (i = 0; i < s->count; i++) {
136 unlock_block(s->info, s->nodes[i]);
137 }
138}
139
140int ro_step(struct ro_spine *s, dm_block_t new_child)
141{
142 int r;
143
144 if (s->count == 2) {
145 unlock_block(s->info, s->nodes[0]);
146 s->nodes[0] = s->nodes[1];
147 s->count--;
148 }
149
150 r = bn_read_lock(s->info, new_child, s->nodes + s->count);
151 if (!r)
152 s->count++;
153
154 return r;
155}
156
157void ro_pop(struct ro_spine *s)
158{
159 BUG_ON(!s->count);
160 --s->count;
161 unlock_block(s->info, s->nodes[s->count]);
162}
163
164struct btree_node *ro_node(struct ro_spine *s)
165{
166 struct dm_block *block;
167
168 BUG_ON(!s->count);
169 block = s->nodes[s->count - 1];
170
171 return dm_block_data(block);
172}
173
174
175
176void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info)
177{
178 s->info = info;
179 s->count = 0;
180}
181
182void exit_shadow_spine(struct shadow_spine *s)
183{
184 int i;
185
186 for (i = 0; i < s->count; i++) {
187 unlock_block(s->info, s->nodes[i]);
188 }
189}
190
191int shadow_step(struct shadow_spine *s, dm_block_t b,
192 struct dm_btree_value_type *vt)
193{
194 int r;
195
196 if (s->count == 2) {
197 unlock_block(s->info, s->nodes[0]);
198 s->nodes[0] = s->nodes[1];
199 s->count--;
200 }
201
202 r = bn_shadow(s->info, b, vt, s->nodes + s->count);
203 if (!r) {
204 if (!s->count)
205 s->root = dm_block_location(s->nodes[0]);
206
207 s->count++;
208 }
209
210 return r;
211}
212
213struct dm_block *shadow_current(struct shadow_spine *s)
214{
215 BUG_ON(!s->count);
216
217 return s->nodes[s->count - 1];
218}
219
220struct dm_block *shadow_parent(struct shadow_spine *s)
221{
222 BUG_ON(s->count != 2);
223
224 return s->count == 2 ? s->nodes[0] : NULL;
225}
226
227int shadow_has_parent(struct shadow_spine *s)
228{
229 return s->count >= 2;
230}
231
232dm_block_t shadow_root(struct shadow_spine *s)
233{
234 return s->root;
235}
236
237static void le64_inc(void *context, const void *value_le, unsigned count)
238{
239 dm_tm_with_runs(context, value_le, count, dm_tm_inc_range);
240}
241
242static void le64_dec(void *context, const void *value_le, unsigned count)
243{
244 dm_tm_with_runs(context, value_le, count, dm_tm_dec_range);
245}
246
247static int le64_equal(void *context, const void *value1_le, const void *value2_le)
248{
249 __le64 v1_le, v2_le;
250
251 memcpy(&v1_le, value1_le, sizeof(v1_le));
252 memcpy(&v2_le, value2_le, sizeof(v2_le));
253 return v1_le == v2_le;
254}
255
256void init_le64_type(struct dm_transaction_manager *tm,
257 struct dm_btree_value_type *vt)
258{
259 vt->context = tm;
260 vt->size = sizeof(__le64);
261 vt->inc = le64_inc;
262 vt->dec = le64_dec;
263 vt->equal = le64_equal;
264}
265
