GNU Linux-libre 4.19.264-gnu1
[releases.git] / drivers / md / persistent-data / dm-btree-spine.c
1 /*
2  * Copyright (C) 2011 Red Hat, Inc.
3  *
4  * This file is released under the GPL.
5  */
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
18 static int node_check(struct dm_block_validator *v,
19                       struct dm_block *b,
20                       size_t block_size);
21
22 static 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
37 static 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          * The node must be either INTERNAL or LEAF.
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
87 struct 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
95 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
101 static 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
115 int 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
120 void unlock_block(struct dm_btree_info *info, struct dm_block *b)
121 {
122         dm_tm_unlock(info->tm, b);
123 }
124
125 /*----------------------------------------------------------------*/
126
127 void 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
135 int exit_ro_spine(struct ro_spine *s)
136 {
137         int r = 0, i;
138
139         for (i = 0; i < s->count; i++) {
140                 unlock_block(s->info, s->nodes[i]);
141         }
142
143         return r;
144 }
145
146 int ro_step(struct ro_spine *s, dm_block_t new_child)
147 {
148         int r;
149
150         if (s->count == 2) {
151                 unlock_block(s->info, s->nodes[0]);
152                 s->nodes[0] = s->nodes[1];
153                 s->count--;
154         }
155
156         r = bn_read_lock(s->info, new_child, s->nodes + s->count);
157         if (!r)
158                 s->count++;
159
160         return r;
161 }
162
163 void ro_pop(struct ro_spine *s)
164 {
165         BUG_ON(!s->count);
166         --s->count;
167         unlock_block(s->info, s->nodes[s->count]);
168 }
169
170 struct btree_node *ro_node(struct ro_spine *s)
171 {
172         struct dm_block *block;
173
174         BUG_ON(!s->count);
175         block = s->nodes[s->count - 1];
176
177         return dm_block_data(block);
178 }
179
180 /*----------------------------------------------------------------*/
181
182 void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info)
183 {
184         s->info = info;
185         s->count = 0;
186 }
187
188 int exit_shadow_spine(struct shadow_spine *s)
189 {
190         int r = 0, i;
191
192         for (i = 0; i < s->count; i++) {
193                 unlock_block(s->info, s->nodes[i]);
194         }
195
196         return r;
197 }
198
199 int shadow_step(struct shadow_spine *s, dm_block_t b,
200                 struct dm_btree_value_type *vt)
201 {
202         int r;
203
204         if (s->count == 2) {
205                 unlock_block(s->info, s->nodes[0]);
206                 s->nodes[0] = s->nodes[1];
207                 s->count--;
208         }
209
210         r = bn_shadow(s->info, b, vt, s->nodes + s->count);
211         if (!r) {
212                 if (!s->count)
213                         s->root = dm_block_location(s->nodes[0]);
214
215                 s->count++;
216         }
217
218         return r;
219 }
220
221 struct dm_block *shadow_current(struct shadow_spine *s)
222 {
223         BUG_ON(!s->count);
224
225         return s->nodes[s->count - 1];
226 }
227
228 struct dm_block *shadow_parent(struct shadow_spine *s)
229 {
230         BUG_ON(s->count != 2);
231
232         return s->count == 2 ? s->nodes[0] : NULL;
233 }
234
235 int shadow_has_parent(struct shadow_spine *s)
236 {
237         return s->count >= 2;
238 }
239
240 int shadow_root(struct shadow_spine *s)
241 {
242         return s->root;
243 }
244
245 static void le64_inc(void *context, const void *value_le)
246 {
247         struct dm_transaction_manager *tm = context;
248         __le64 v_le;
249
250         memcpy(&v_le, value_le, sizeof(v_le));
251         dm_tm_inc(tm, le64_to_cpu(v_le));
252 }
253
254 static void le64_dec(void *context, const void *value_le)
255 {
256         struct dm_transaction_manager *tm = context;
257         __le64 v_le;
258
259         memcpy(&v_le, value_le, sizeof(v_le));
260         dm_tm_dec(tm, le64_to_cpu(v_le));
261 }
262
263 static int le64_equal(void *context, const void *value1_le, const void *value2_le)
264 {
265         __le64 v1_le, v2_le;
266
267         memcpy(&v1_le, value1_le, sizeof(v1_le));
268         memcpy(&v2_le, value2_le, sizeof(v2_le));
269         return v1_le == v2_le;
270 }
271
272 void init_le64_type(struct dm_transaction_manager *tm,
273                     struct dm_btree_value_type *vt)
274 {
275         vt->context = tm;
276         vt->size = sizeof(__le64);
277         vt->inc = le64_inc;
278         vt->dec = le64_dec;
279         vt->equal = le64_equal;
280 }