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8#include "btrfs.h"
9#include <malloc.h>
10#include <memalign.h>
11
12int btrfs_comp_keys(struct btrfs_key *a, struct btrfs_key *b)
13{
14 if (a->objectid > b->objectid)
15 return 1;
16 if (a->objectid < b->objectid)
17 return -1;
18 if (a->type > b->type)
19 return 1;
20 if (a->type < b->type)
21 return -1;
22 if (a->offset > b->offset)
23 return 1;
24 if (a->offset < b->offset)
25 return -1;
26 return 0;
27}
28
29int btrfs_comp_keys_type(struct btrfs_key *a, struct btrfs_key *b)
30{
31 if (a->objectid > b->objectid)
32 return 1;
33 if (a->objectid < b->objectid)
34 return -1;
35 if (a->type > b->type)
36 return 1;
37 if (a->type < b->type)
38 return -1;
39 return 0;
40}
41
42static int generic_bin_search(void *addr, int item_size, struct btrfs_key *key,
43 int max, int *slot)
44{
45 int low = 0, high = max, mid, ret;
46 struct btrfs_key *tmp;
47
48 while (low < high) {
49 mid = (low + high) / 2;
50
51 tmp = (struct btrfs_key *) ((u8 *) addr + mid*item_size);
52 ret = btrfs_comp_keys(tmp, key);
53
54 if (ret < 0) {
55 low = mid + 1;
56 } else if (ret > 0) {
57 high = mid;
58 } else {
59 *slot = mid;
60 return 0;
61 }
62 }
63
64 *slot = low;
65 return 1;
66}
67
68int btrfs_bin_search(union btrfs_tree_node *p, struct btrfs_key *key,
69 int *slot)
70{
71 void *addr;
72 unsigned long size;
73
74 if (p->header.level) {
75 addr = p->node.ptrs;
76 size = sizeof(struct btrfs_key_ptr);
77 } else {
78 addr = p->leaf.items;
79 size = sizeof(struct btrfs_item);
80 }
81
82 return generic_bin_search(addr, size, key, p->header.nritems, slot);
83}
84
85static void clear_path(struct btrfs_path *p)
86{
87 int i;
88
89 for (i = 0; i < BTRFS_MAX_LEVEL; ++i) {
90 p->nodes[i] = NULL;
91 p->slots[i] = 0;
92 }
93}
94
95void btrfs_free_path(struct btrfs_path *p)
96{
97 int i;
98
99 for (i = 0; i < BTRFS_MAX_LEVEL; ++i) {
100 if (p->nodes[i])
101 free(p->nodes[i]);
102 }
103
104 clear_path(p);
105}
106
107static int read_tree_node(u64 physical, union btrfs_tree_node **buf)
108{
109 ALLOC_CACHE_ALIGN_BUFFER(struct btrfs_header, hdr,
110 sizeof(struct btrfs_header));
111 unsigned long size, offset = sizeof(*hdr);
112 union btrfs_tree_node *res;
113 u32 i;
114
115 if (!btrfs_devread(physical, sizeof(*hdr), hdr))
116 return -1;
117
118 btrfs_header_to_cpu(hdr);
119
120 if (hdr->level)
121 size = sizeof(struct btrfs_node)
122 + hdr->nritems * sizeof(struct btrfs_key_ptr);
123 else
124 size = btrfs_info.sb.nodesize;
125
126 res = malloc_cache_aligned(size);
127 if (!res) {
128 debug("%s: malloc failed\n", __func__);
129 return -1;
130 }
131
132 if (!btrfs_devread(physical + offset, size - offset,
133 ((u8 *) res) + offset)) {
134 free(res);
135 return -1;
136 }
137
138 memcpy(&res->header, hdr, sizeof(*hdr));
139 if (hdr->level)
140 for (i = 0; i < hdr->nritems; ++i)
141 btrfs_key_ptr_to_cpu(&res->node.ptrs[i]);
142 else
143 for (i = 0; i < hdr->nritems; ++i)
144 btrfs_item_to_cpu(&res->leaf.items[i]);
145
146 *buf = res;
147
148 return 0;
149}
150
151int btrfs_search_tree(const struct btrfs_root *root, struct btrfs_key *key,
152 struct btrfs_path *p)
153{
154 u8 lvl, prev_lvl;
155 int i, slot, ret;
156 u64 logical, physical;
157 union btrfs_tree_node *buf;
158
159 clear_path(p);
160
161 logical = root->bytenr;
162
163 for (i = 0; i < BTRFS_MAX_LEVEL; ++i) {
164 physical = btrfs_map_logical_to_physical(logical);
165 if (physical == -1ULL)
166 goto err;
167
168 if (read_tree_node(physical, &buf))
169 goto err;
170
171 lvl = buf->header.level;
172 if (i && prev_lvl != lvl + 1) {
173 printf("%s: invalid level in header at %llu\n",
174 __func__, logical);
175 goto err;
176 }
177 prev_lvl = lvl;
178
179 ret = btrfs_bin_search(buf, key, &slot);
180 if (ret < 0)
181 goto err;
182 if (ret && slot > 0 && lvl)
183 slot -= 1;
184
185 p->slots[lvl] = slot;
186 p->nodes[lvl] = buf;
187
188 if (lvl)
189 logical = buf->node.ptrs[slot].blockptr;
190 else
191 break;
192 }
193
194 return 0;
195err:
196 btrfs_free_path(p);
197 return -1;
198}
199
200static int jump_leaf(struct btrfs_path *path, int dir)
201{
202 struct btrfs_path p;
203 u32 slot;
204 int level = 1, from_level, i;
205
206 dir = dir >= 0 ? 1 : -1;
207
208 p = *path;
209
210 while (level < BTRFS_MAX_LEVEL) {
211 if (!p.nodes[level])
212 return 1;
213
214 slot = p.slots[level];
215 if ((dir > 0 && slot + dir >= p.nodes[level]->header.nritems)
216 || (dir < 0 && !slot))
217 level++;
218 else
219 break;
220 }
221
222 if (level == BTRFS_MAX_LEVEL)
223 return 1;
224
225 p.slots[level] = slot + dir;
226 level--;
227 from_level = level;
228
229 while (level >= 0) {
230 u64 logical, physical;
231
232 slot = p.slots[level + 1];
233 logical = p.nodes[level + 1]->node.ptrs[slot].blockptr;
234 physical = btrfs_map_logical_to_physical(logical);
235 if (physical == -1ULL)
236 goto err;
237
238 if (read_tree_node(physical, &p.nodes[level]))
239 goto err;
240
241 if (dir > 0)
242 p.slots[level] = 0;
243 else
244 p.slots[level] = p.nodes[level]->header.nritems - 1;
245 level--;
246 }
247
248
249 for (i = 0; i <= from_level; ++i)
250 free(path->nodes[i]);
251
252 *path = p;
253 return 0;
254
255err:
256
257 for (i = level + 1; i <= from_level; ++i)
258 free(p.nodes[i]);
259 return -1;
260}
261
262int btrfs_prev_slot(struct btrfs_path *p)
263{
264 if (!p->slots[0])
265 return jump_leaf(p, -1);
266
267 p->slots[0]--;
268 return 0;
269}
270
271int btrfs_next_slot(struct btrfs_path *p)
272{
273 struct btrfs_leaf *leaf = &p->nodes[0]->leaf;
274
275 if (p->slots[0] + 1 >= leaf->header.nritems)
276 return jump_leaf(p, 1);
277
278 p->slots[0]++;
279 return 0;
280}
281
