Commit | Line | Data |
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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; | |
c2b3e1f7 | 25 | hfs_dbg(BNODE_REFS, "find_init: %d (%p)\n", |
2753cc28 | 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); | |
c2b3e1f7 | 47 | hfs_dbg(BNODE_REFS, "find_exit: %d (%p)\n", |
2753cc28 | 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 | { | |
5f3726f9 VD |
59 | __be32 cur_cnid; |
60 | __be32 search_cnid; | |
324ef39a VD |
61 | |
62 | if (bnode->tree->cnid == HFSPLUS_EXT_CNID) { | |
63 | cur_cnid = fd->key->ext.cnid; | |
64 | search_cnid = fd->search_key->ext.cnid; | |
65 | } else if (bnode->tree->cnid == HFSPLUS_CAT_CNID) { | |
66 | cur_cnid = fd->key->cat.parent; | |
67 | search_cnid = fd->search_key->cat.parent; | |
68 | } else if (bnode->tree->cnid == HFSPLUS_ATTR_CNID) { | |
69 | cur_cnid = fd->key->attr.cnid; | |
70 | search_cnid = fd->search_key->attr.cnid; | |
5f3726f9 VD |
71 | } else { |
72 | cur_cnid = 0; /* used-uninitialized warning */ | |
73 | search_cnid = 0; | |
324ef39a | 74 | BUG(); |
5f3726f9 | 75 | } |
324ef39a VD |
76 | |
77 | if (cur_cnid == search_cnid) { | |
78 | (*end) = (*cur_rec); | |
79 | if ((*begin) == (*end)) | |
80 | return 1; | |
81 | } else { | |
82 | if (be32_to_cpu(cur_cnid) < be32_to_cpu(search_cnid)) | |
83 | (*begin) = (*cur_rec) + 1; | |
84 | else | |
85 | (*end) = (*cur_rec) - 1; | |
86 | } | |
87 | ||
88 | return 0; | |
89 | } | |
90 | ||
91 | int hfs_find_rec_by_key(struct hfs_bnode *bnode, | |
92 | struct hfs_find_data *fd, | |
93 | int *begin, | |
94 | int *end, | |
95 | int *cur_rec) | |
1da177e4 LT |
96 | { |
97 | int cmpval; | |
324ef39a VD |
98 | |
99 | cmpval = bnode->tree->keycmp(fd->key, fd->search_key); | |
100 | if (!cmpval) { | |
101 | (*end) = (*cur_rec); | |
102 | return 1; | |
103 | } | |
104 | if (cmpval < 0) | |
105 | (*begin) = (*cur_rec) + 1; | |
106 | else | |
107 | *(end) = (*cur_rec) - 1; | |
108 | ||
109 | return 0; | |
110 | } | |
111 | ||
112 | /* Find the record in bnode that best matches key (not greater than...)*/ | |
113 | int __hfs_brec_find(struct hfs_bnode *bnode, struct hfs_find_data *fd, | |
114 | search_strategy_t rec_found) | |
115 | { | |
1da177e4 LT |
116 | u16 off, len, keylen; |
117 | int rec; | |
118 | int b, e; | |
119 | int res; | |
120 | ||
324ef39a VD |
121 | if (!rec_found) |
122 | BUG(); | |
123 | ||
1da177e4 LT |
124 | b = 0; |
125 | e = bnode->num_recs - 1; | |
126 | res = -ENOENT; | |
127 | do { | |
128 | rec = (e + b) / 2; | |
129 | len = hfs_brec_lenoff(bnode, rec, &off); | |
130 | keylen = hfs_brec_keylen(bnode, rec); | |
9250f925 ES |
131 | if (keylen == 0) { |
132 | res = -EINVAL; | |
133 | goto fail; | |
134 | } | |
1da177e4 | 135 | hfs_bnode_read(bnode, fd->key, off, keylen); |
324ef39a | 136 | if (rec_found(bnode, fd, &b, &e, &rec)) { |
1da177e4 LT |
137 | res = 0; |
138 | goto done; | |
139 | } | |
1da177e4 | 140 | } while (b <= e); |
324ef39a | 141 | |
1da177e4 LT |
142 | if (rec != e && e >= 0) { |
143 | len = hfs_brec_lenoff(bnode, e, &off); | |
144 | keylen = hfs_brec_keylen(bnode, e); | |
9250f925 ES |
145 | if (keylen == 0) { |
146 | res = -EINVAL; | |
147 | goto fail; | |
148 | } | |
1da177e4 LT |
149 | hfs_bnode_read(bnode, fd->key, off, keylen); |
150 | } | |
324ef39a | 151 | |
1da177e4 LT |
152 | done: |
153 | fd->record = e; | |
154 | fd->keyoffset = off; | |
155 | fd->keylength = keylen; | |
156 | fd->entryoffset = off + keylen; | |
157 | fd->entrylength = len - keylen; | |
324ef39a | 158 | |
9250f925 | 159 | fail: |
1da177e4 LT |
160 | return res; |
161 | } | |
162 | ||
163 | /* Traverse a B*Tree from the root to a leaf finding best fit to key */ | |
164 | /* Return allocated copy of node found, set recnum to best record */ | |
324ef39a | 165 | int hfs_brec_find(struct hfs_find_data *fd, search_strategy_t do_key_compare) |
1da177e4 LT |
166 | { |
167 | struct hfs_btree *tree; | |
168 | struct hfs_bnode *bnode; | |
169 | u32 nidx, parent; | |
170 | __be32 data; | |
171 | int height, res; | |
172 | ||
173 | tree = fd->tree; | |
174 | if (fd->bnode) | |
175 | hfs_bnode_put(fd->bnode); | |
176 | fd->bnode = NULL; | |
177 | nidx = tree->root; | |
178 | if (!nidx) | |
179 | return -ENOENT; | |
180 | height = tree->depth; | |
181 | res = 0; | |
182 | parent = 0; | |
183 | for (;;) { | |
184 | bnode = hfs_bnode_find(tree, nidx); | |
185 | if (IS_ERR(bnode)) { | |
186 | res = PTR_ERR(bnode); | |
187 | bnode = NULL; | |
188 | break; | |
189 | } | |
190 | if (bnode->height != height) | |
191 | goto invalid; | |
192 | if (bnode->type != (--height ? HFS_NODE_INDEX : HFS_NODE_LEAF)) | |
193 | goto invalid; | |
194 | bnode->parent = parent; | |
195 | ||
324ef39a | 196 | res = __hfs_brec_find(bnode, fd, do_key_compare); |
1da177e4 LT |
197 | if (!height) |
198 | break; | |
199 | if (fd->record < 0) | |
200 | goto release; | |
201 | ||
202 | parent = nidx; | |
203 | hfs_bnode_read(bnode, &data, fd->entryoffset, 4); | |
204 | nidx = be32_to_cpu(data); | |
205 | hfs_bnode_put(bnode); | |
206 | } | |
207 | fd->bnode = bnode; | |
208 | return res; | |
209 | ||
210 | invalid: | |
d6142673 | 211 | pr_err("inconsistency in B*Tree (%d,%d,%d,%u,%u)\n", |
1da177e4 LT |
212 | height, bnode->height, bnode->type, nidx, parent); |
213 | res = -EIO; | |
214 | release: | |
215 | hfs_bnode_put(bnode); | |
216 | return res; | |
217 | } | |
218 | ||
219 | int hfs_brec_read(struct hfs_find_data *fd, void *rec, int rec_len) | |
220 | { | |
221 | int res; | |
222 | ||
324ef39a | 223 | res = hfs_brec_find(fd, hfs_find_rec_by_key); |
1da177e4 LT |
224 | if (res) |
225 | return res; | |
226 | if (fd->entrylength > rec_len) | |
227 | return -EINVAL; | |
228 | hfs_bnode_read(fd->bnode, rec, fd->entryoffset, fd->entrylength); | |
229 | return 0; | |
230 | } | |
231 | ||
232 | int hfs_brec_goto(struct hfs_find_data *fd, int cnt) | |
233 | { | |
234 | struct hfs_btree *tree; | |
235 | struct hfs_bnode *bnode; | |
236 | int idx, res = 0; | |
237 | u16 off, len, keylen; | |
238 | ||
239 | bnode = fd->bnode; | |
240 | tree = bnode->tree; | |
241 | ||
242 | if (cnt < 0) { | |
243 | cnt = -cnt; | |
244 | while (cnt > fd->record) { | |
245 | cnt -= fd->record + 1; | |
246 | fd->record = bnode->num_recs - 1; | |
247 | idx = bnode->prev; | |
248 | if (!idx) { | |
249 | res = -ENOENT; | |
250 | goto out; | |
251 | } | |
252 | hfs_bnode_put(bnode); | |
253 | bnode = hfs_bnode_find(tree, idx); | |
254 | if (IS_ERR(bnode)) { | |
255 | res = PTR_ERR(bnode); | |
256 | bnode = NULL; | |
257 | goto out; | |
258 | } | |
259 | } | |
260 | fd->record -= cnt; | |
261 | } else { | |
262 | while (cnt >= bnode->num_recs - fd->record) { | |
263 | cnt -= bnode->num_recs - fd->record; | |
264 | fd->record = 0; | |
265 | idx = bnode->next; | |
266 | if (!idx) { | |
267 | res = -ENOENT; | |
268 | goto out; | |
269 | } | |
270 | hfs_bnode_put(bnode); | |
271 | bnode = hfs_bnode_find(tree, idx); | |
272 | if (IS_ERR(bnode)) { | |
273 | res = PTR_ERR(bnode); | |
274 | bnode = NULL; | |
275 | goto out; | |
276 | } | |
277 | } | |
278 | fd->record += cnt; | |
279 | } | |
280 | ||
281 | len = hfs_brec_lenoff(bnode, fd->record, &off); | |
282 | keylen = hfs_brec_keylen(bnode, fd->record); | |
9250f925 ES |
283 | if (keylen == 0) { |
284 | res = -EINVAL; | |
285 | goto out; | |
286 | } | |
1da177e4 LT |
287 | fd->keyoffset = off; |
288 | fd->keylength = keylen; | |
289 | fd->entryoffset = off + keylen; | |
290 | fd->entrylength = len - keylen; | |
291 | hfs_bnode_read(bnode, fd->key, off, keylen); | |
292 | out: | |
293 | fd->bnode = bnode; | |
294 | return res; | |
295 | } |