Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/hfsplus/bfind.c | |
3 | * | |
4 | * Copyright (C) 2001 | |
5 | * Brad Boyer (flar@allandria.com) | |
6 | * (C) 2003 Ardis Technologies <roman@ardistech.com> | |
7 | * | |
8 | * Search routines for btrees | |
9 | */ | |
10 | ||
11 | #include <linux/slab.h> | |
12 | #include "hfsplus_fs.h" | |
13 | ||
14 | int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd) | |
15 | { | |
16 | void *ptr; | |
17 | ||
18 | fd->tree = tree; | |
19 | fd->bnode = NULL; | |
20 | ptr = kmalloc(tree->max_key_len * 2 + 4, GFP_KERNEL); | |
21 | if (!ptr) | |
22 | return -ENOMEM; | |
23 | fd->search_key = ptr; | |
24 | fd->key = ptr + tree->max_key_len + 2; | |
2753cc28 AS |
25 | dprint(DBG_BNODE_REFS, "find_init: %d (%p)\n", |
26 | tree->cnid, __builtin_return_address(0)); | |
324ef39a VD |
27 | switch (tree->cnid) { |
28 | case HFSPLUS_CAT_CNID: | |
29 | mutex_lock_nested(&tree->tree_lock, CATALOG_BTREE_MUTEX); | |
30 | break; | |
31 | case HFSPLUS_EXT_CNID: | |
32 | mutex_lock_nested(&tree->tree_lock, EXTENTS_BTREE_MUTEX); | |
33 | break; | |
34 | case HFSPLUS_ATTR_CNID: | |
35 | mutex_lock_nested(&tree->tree_lock, ATTR_BTREE_MUTEX); | |
36 | break; | |
37 | default: | |
38 | BUG(); | |
39 | } | |
1da177e4 LT |
40 | return 0; |
41 | } | |
42 | ||
43 | void hfs_find_exit(struct hfs_find_data *fd) | |
44 | { | |
45 | hfs_bnode_put(fd->bnode); | |
46 | kfree(fd->search_key); | |
2753cc28 AS |
47 | dprint(DBG_BNODE_REFS, "find_exit: %d (%p)\n", |
48 | fd->tree->cnid, __builtin_return_address(0)); | |
467c3d9c | 49 | mutex_unlock(&fd->tree->tree_lock); |
1da177e4 LT |
50 | fd->tree = NULL; |
51 | } | |
52 | ||
324ef39a VD |
53 | int hfs_find_1st_rec_by_cnid(struct hfs_bnode *bnode, |
54 | struct hfs_find_data *fd, | |
55 | int *begin, | |
56 | int *end, | |
57 | int *cur_rec) | |
58 | { | |
59 | __be32 cur_cnid, search_cnid; | |
60 | ||
61 | if (bnode->tree->cnid == HFSPLUS_EXT_CNID) { | |
62 | cur_cnid = fd->key->ext.cnid; | |
63 | search_cnid = fd->search_key->ext.cnid; | |
64 | } else if (bnode->tree->cnid == HFSPLUS_CAT_CNID) { | |
65 | cur_cnid = fd->key->cat.parent; | |
66 | search_cnid = fd->search_key->cat.parent; | |
67 | } else if (bnode->tree->cnid == HFSPLUS_ATTR_CNID) { | |
68 | cur_cnid = fd->key->attr.cnid; | |
69 | search_cnid = fd->search_key->attr.cnid; | |
70 | } else | |
71 | BUG(); | |
72 | ||
73 | if (cur_cnid == search_cnid) { | |
74 | (*end) = (*cur_rec); | |
75 | if ((*begin) == (*end)) | |
76 | return 1; | |
77 | } else { | |
78 | if (be32_to_cpu(cur_cnid) < be32_to_cpu(search_cnid)) | |
79 | (*begin) = (*cur_rec) + 1; | |
80 | else | |
81 | (*end) = (*cur_rec) - 1; | |
82 | } | |
83 | ||
84 | return 0; | |
85 | } | |
86 | ||
87 | int hfs_find_rec_by_key(struct hfs_bnode *bnode, | |
88 | struct hfs_find_data *fd, | |
89 | int *begin, | |
90 | int *end, | |
91 | int *cur_rec) | |
1da177e4 LT |
92 | { |
93 | int cmpval; | |
324ef39a VD |
94 | |
95 | cmpval = bnode->tree->keycmp(fd->key, fd->search_key); | |
96 | if (!cmpval) { | |
97 | (*end) = (*cur_rec); | |
98 | return 1; | |
99 | } | |
100 | if (cmpval < 0) | |
101 | (*begin) = (*cur_rec) + 1; | |
102 | else | |
103 | *(end) = (*cur_rec) - 1; | |
104 | ||
105 | return 0; | |
106 | } | |
107 | ||
108 | /* Find the record in bnode that best matches key (not greater than...)*/ | |
109 | int __hfs_brec_find(struct hfs_bnode *bnode, struct hfs_find_data *fd, | |
110 | search_strategy_t rec_found) | |
111 | { | |
1da177e4 LT |
112 | u16 off, len, keylen; |
113 | int rec; | |
114 | int b, e; | |
115 | int res; | |
116 | ||
324ef39a VD |
117 | if (!rec_found) |
118 | BUG(); | |
119 | ||
1da177e4 LT |
120 | b = 0; |
121 | e = bnode->num_recs - 1; | |
122 | res = -ENOENT; | |
123 | do { | |
124 | rec = (e + b) / 2; | |
125 | len = hfs_brec_lenoff(bnode, rec, &off); | |
126 | keylen = hfs_brec_keylen(bnode, rec); | |
9250f925 ES |
127 | if (keylen == 0) { |
128 | res = -EINVAL; | |
129 | goto fail; | |
130 | } | |
1da177e4 | 131 | hfs_bnode_read(bnode, fd->key, off, keylen); |
324ef39a | 132 | if (rec_found(bnode, fd, &b, &e, &rec)) { |
1da177e4 LT |
133 | res = 0; |
134 | goto done; | |
135 | } | |
1da177e4 | 136 | } while (b <= e); |
324ef39a | 137 | |
1da177e4 LT |
138 | if (rec != e && e >= 0) { |
139 | len = hfs_brec_lenoff(bnode, e, &off); | |
140 | keylen = hfs_brec_keylen(bnode, e); | |
9250f925 ES |
141 | if (keylen == 0) { |
142 | res = -EINVAL; | |
143 | goto fail; | |
144 | } | |
1da177e4 LT |
145 | hfs_bnode_read(bnode, fd->key, off, keylen); |
146 | } | |
324ef39a | 147 | |
1da177e4 LT |
148 | done: |
149 | fd->record = e; | |
150 | fd->keyoffset = off; | |
151 | fd->keylength = keylen; | |
152 | fd->entryoffset = off + keylen; | |
153 | fd->entrylength = len - keylen; | |
324ef39a | 154 | |
9250f925 | 155 | fail: |
1da177e4 LT |
156 | return res; |
157 | } | |
158 | ||
159 | /* Traverse a B*Tree from the root to a leaf finding best fit to key */ | |
160 | /* Return allocated copy of node found, set recnum to best record */ | |
324ef39a | 161 | int hfs_brec_find(struct hfs_find_data *fd, search_strategy_t do_key_compare) |
1da177e4 LT |
162 | { |
163 | struct hfs_btree *tree; | |
164 | struct hfs_bnode *bnode; | |
165 | u32 nidx, parent; | |
166 | __be32 data; | |
167 | int height, res; | |
168 | ||
169 | tree = fd->tree; | |
170 | if (fd->bnode) | |
171 | hfs_bnode_put(fd->bnode); | |
172 | fd->bnode = NULL; | |
173 | nidx = tree->root; | |
174 | if (!nidx) | |
175 | return -ENOENT; | |
176 | height = tree->depth; | |
177 | res = 0; | |
178 | parent = 0; | |
179 | for (;;) { | |
180 | bnode = hfs_bnode_find(tree, nidx); | |
181 | if (IS_ERR(bnode)) { | |
182 | res = PTR_ERR(bnode); | |
183 | bnode = NULL; | |
184 | break; | |
185 | } | |
186 | if (bnode->height != height) | |
187 | goto invalid; | |
188 | if (bnode->type != (--height ? HFS_NODE_INDEX : HFS_NODE_LEAF)) | |
189 | goto invalid; | |
190 | bnode->parent = parent; | |
191 | ||
324ef39a | 192 | res = __hfs_brec_find(bnode, fd, do_key_compare); |
1da177e4 LT |
193 | if (!height) |
194 | break; | |
195 | if (fd->record < 0) | |
196 | goto release; | |
197 | ||
198 | parent = nidx; | |
199 | hfs_bnode_read(bnode, &data, fd->entryoffset, 4); | |
200 | nidx = be32_to_cpu(data); | |
201 | hfs_bnode_put(bnode); | |
202 | } | |
203 | fd->bnode = bnode; | |
204 | return res; | |
205 | ||
206 | invalid: | |
634725a9 | 207 | printk(KERN_ERR "hfs: inconsistency in B*Tree (%d,%d,%d,%u,%u)\n", |
1da177e4 LT |
208 | height, bnode->height, bnode->type, nidx, parent); |
209 | res = -EIO; | |
210 | release: | |
211 | hfs_bnode_put(bnode); | |
212 | return res; | |
213 | } | |
214 | ||
215 | int hfs_brec_read(struct hfs_find_data *fd, void *rec, int rec_len) | |
216 | { | |
217 | int res; | |
218 | ||
324ef39a | 219 | res = hfs_brec_find(fd, hfs_find_rec_by_key); |
1da177e4 LT |
220 | if (res) |
221 | return res; | |
222 | if (fd->entrylength > rec_len) | |
223 | return -EINVAL; | |
224 | hfs_bnode_read(fd->bnode, rec, fd->entryoffset, fd->entrylength); | |
225 | return 0; | |
226 | } | |
227 | ||
228 | int hfs_brec_goto(struct hfs_find_data *fd, int cnt) | |
229 | { | |
230 | struct hfs_btree *tree; | |
231 | struct hfs_bnode *bnode; | |
232 | int idx, res = 0; | |
233 | u16 off, len, keylen; | |
234 | ||
235 | bnode = fd->bnode; | |
236 | tree = bnode->tree; | |
237 | ||
238 | if (cnt < 0) { | |
239 | cnt = -cnt; | |
240 | while (cnt > fd->record) { | |
241 | cnt -= fd->record + 1; | |
242 | fd->record = bnode->num_recs - 1; | |
243 | idx = bnode->prev; | |
244 | if (!idx) { | |
245 | res = -ENOENT; | |
246 | goto out; | |
247 | } | |
248 | hfs_bnode_put(bnode); | |
249 | bnode = hfs_bnode_find(tree, idx); | |
250 | if (IS_ERR(bnode)) { | |
251 | res = PTR_ERR(bnode); | |
252 | bnode = NULL; | |
253 | goto out; | |
254 | } | |
255 | } | |
256 | fd->record -= cnt; | |
257 | } else { | |
258 | while (cnt >= bnode->num_recs - fd->record) { | |
259 | cnt -= bnode->num_recs - fd->record; | |
260 | fd->record = 0; | |
261 | idx = bnode->next; | |
262 | if (!idx) { | |
263 | res = -ENOENT; | |
264 | goto out; | |
265 | } | |
266 | hfs_bnode_put(bnode); | |
267 | bnode = hfs_bnode_find(tree, idx); | |
268 | if (IS_ERR(bnode)) { | |
269 | res = PTR_ERR(bnode); | |
270 | bnode = NULL; | |
271 | goto out; | |
272 | } | |
273 | } | |
274 | fd->record += cnt; | |
275 | } | |
276 | ||
277 | len = hfs_brec_lenoff(bnode, fd->record, &off); | |
278 | keylen = hfs_brec_keylen(bnode, fd->record); | |
9250f925 ES |
279 | if (keylen == 0) { |
280 | res = -EINVAL; | |
281 | goto out; | |
282 | } | |
1da177e4 LT |
283 | fd->keyoffset = off; |
284 | fd->keylength = keylen; | |
285 | fd->entryoffset = off + keylen; | |
286 | fd->entrylength = len - keylen; | |
287 | hfs_bnode_read(bnode, fd->key, off, keylen); | |
288 | out: | |
289 | fd->bnode = bnode; | |
290 | return res; | |
291 | } |