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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * linux/fs/hfsplus/bfind.c | |
4 | * | |
5 | * Copyright (C) 2001 | |
6 | * Brad Boyer (flar@allandria.com) | |
7 | * (C) 2003 Ardis Technologies <roman@ardistech.com> | |
8 | * | |
9 | * Search routines for btrees | |
10 | */ | |
11 | ||
12 | #include <linux/slab.h> | |
13 | #include "hfsplus_fs.h" | |
14 | ||
15 | int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd) | |
16 | { | |
17 | void *ptr; | |
18 | ||
19 | fd->tree = tree; | |
20 | fd->bnode = NULL; | |
21 | ptr = kmalloc(tree->max_key_len * 2 + 4, GFP_KERNEL); | |
22 | if (!ptr) | |
23 | return -ENOMEM; | |
24 | fd->search_key = ptr; | |
25 | fd->key = ptr + tree->max_key_len + 2; | |
c2b3e1f7 | 26 | hfs_dbg(BNODE_REFS, "find_init: %d (%p)\n", |
2753cc28 | 27 | tree->cnid, __builtin_return_address(0)); |
324ef39a VD |
28 | switch (tree->cnid) { |
29 | case HFSPLUS_CAT_CNID: | |
30 | mutex_lock_nested(&tree->tree_lock, CATALOG_BTREE_MUTEX); | |
31 | break; | |
32 | case HFSPLUS_EXT_CNID: | |
33 | mutex_lock_nested(&tree->tree_lock, EXTENTS_BTREE_MUTEX); | |
34 | break; | |
35 | case HFSPLUS_ATTR_CNID: | |
36 | mutex_lock_nested(&tree->tree_lock, ATTR_BTREE_MUTEX); | |
37 | break; | |
38 | default: | |
39 | BUG(); | |
40 | } | |
1da177e4 LT |
41 | return 0; |
42 | } | |
43 | ||
44 | void hfs_find_exit(struct hfs_find_data *fd) | |
45 | { | |
46 | hfs_bnode_put(fd->bnode); | |
47 | kfree(fd->search_key); | |
c2b3e1f7 | 48 | hfs_dbg(BNODE_REFS, "find_exit: %d (%p)\n", |
2753cc28 | 49 | fd->tree->cnid, __builtin_return_address(0)); |
467c3d9c | 50 | mutex_unlock(&fd->tree->tree_lock); |
1da177e4 LT |
51 | fd->tree = NULL; |
52 | } | |
53 | ||
324ef39a VD |
54 | int hfs_find_1st_rec_by_cnid(struct hfs_bnode *bnode, |
55 | struct hfs_find_data *fd, | |
56 | int *begin, | |
57 | int *end, | |
58 | int *cur_rec) | |
59 | { | |
5f3726f9 VD |
60 | __be32 cur_cnid; |
61 | __be32 search_cnid; | |
324ef39a VD |
62 | |
63 | if (bnode->tree->cnid == HFSPLUS_EXT_CNID) { | |
64 | cur_cnid = fd->key->ext.cnid; | |
65 | search_cnid = fd->search_key->ext.cnid; | |
66 | } else if (bnode->tree->cnid == HFSPLUS_CAT_CNID) { | |
67 | cur_cnid = fd->key->cat.parent; | |
68 | search_cnid = fd->search_key->cat.parent; | |
69 | } else if (bnode->tree->cnid == HFSPLUS_ATTR_CNID) { | |
70 | cur_cnid = fd->key->attr.cnid; | |
71 | search_cnid = fd->search_key->attr.cnid; | |
5f3726f9 VD |
72 | } else { |
73 | cur_cnid = 0; /* used-uninitialized warning */ | |
74 | search_cnid = 0; | |
324ef39a | 75 | BUG(); |
5f3726f9 | 76 | } |
324ef39a VD |
77 | |
78 | if (cur_cnid == search_cnid) { | |
79 | (*end) = (*cur_rec); | |
80 | if ((*begin) == (*end)) | |
81 | return 1; | |
82 | } else { | |
83 | if (be32_to_cpu(cur_cnid) < be32_to_cpu(search_cnid)) | |
84 | (*begin) = (*cur_rec) + 1; | |
85 | else | |
86 | (*end) = (*cur_rec) - 1; | |
87 | } | |
88 | ||
89 | return 0; | |
90 | } | |
91 | ||
92 | int hfs_find_rec_by_key(struct hfs_bnode *bnode, | |
93 | struct hfs_find_data *fd, | |
94 | int *begin, | |
95 | int *end, | |
96 | int *cur_rec) | |
1da177e4 LT |
97 | { |
98 | int cmpval; | |
324ef39a VD |
99 | |
100 | cmpval = bnode->tree->keycmp(fd->key, fd->search_key); | |
101 | if (!cmpval) { | |
102 | (*end) = (*cur_rec); | |
103 | return 1; | |
104 | } | |
105 | if (cmpval < 0) | |
106 | (*begin) = (*cur_rec) + 1; | |
107 | else | |
108 | *(end) = (*cur_rec) - 1; | |
109 | ||
110 | return 0; | |
111 | } | |
112 | ||
113 | /* Find the record in bnode that best matches key (not greater than...)*/ | |
114 | int __hfs_brec_find(struct hfs_bnode *bnode, struct hfs_find_data *fd, | |
115 | search_strategy_t rec_found) | |
116 | { | |
1da177e4 LT |
117 | u16 off, len, keylen; |
118 | int rec; | |
119 | int b, e; | |
120 | int res; | |
121 | ||
7ce844a2 | 122 | BUG_ON(!rec_found); |
1da177e4 LT |
123 | b = 0; |
124 | e = bnode->num_recs - 1; | |
125 | res = -ENOENT; | |
126 | do { | |
127 | rec = (e + b) / 2; | |
128 | len = hfs_brec_lenoff(bnode, rec, &off); | |
129 | keylen = hfs_brec_keylen(bnode, rec); | |
9250f925 ES |
130 | if (keylen == 0) { |
131 | res = -EINVAL; | |
132 | goto fail; | |
133 | } | |
1da177e4 | 134 | hfs_bnode_read(bnode, fd->key, off, keylen); |
324ef39a | 135 | if (rec_found(bnode, fd, &b, &e, &rec)) { |
1da177e4 LT |
136 | res = 0; |
137 | goto done; | |
138 | } | |
1da177e4 | 139 | } while (b <= e); |
324ef39a | 140 | |
1da177e4 LT |
141 | if (rec != e && e >= 0) { |
142 | len = hfs_brec_lenoff(bnode, e, &off); | |
143 | keylen = hfs_brec_keylen(bnode, e); | |
9250f925 ES |
144 | if (keylen == 0) { |
145 | res = -EINVAL; | |
146 | goto fail; | |
147 | } | |
1da177e4 LT |
148 | hfs_bnode_read(bnode, fd->key, off, keylen); |
149 | } | |
324ef39a | 150 | |
1da177e4 LT |
151 | done: |
152 | fd->record = e; | |
153 | fd->keyoffset = off; | |
154 | fd->keylength = keylen; | |
155 | fd->entryoffset = off + keylen; | |
156 | fd->entrylength = len - keylen; | |
324ef39a | 157 | |
9250f925 | 158 | fail: |
1da177e4 LT |
159 | return res; |
160 | } | |
161 | ||
162 | /* Traverse a B*Tree from the root to a leaf finding best fit to key */ | |
163 | /* Return allocated copy of node found, set recnum to best record */ | |
324ef39a | 164 | int hfs_brec_find(struct hfs_find_data *fd, search_strategy_t do_key_compare) |
1da177e4 LT |
165 | { |
166 | struct hfs_btree *tree; | |
167 | struct hfs_bnode *bnode; | |
168 | u32 nidx, parent; | |
169 | __be32 data; | |
170 | int height, res; | |
171 | ||
172 | tree = fd->tree; | |
173 | if (fd->bnode) | |
174 | hfs_bnode_put(fd->bnode); | |
175 | fd->bnode = NULL; | |
176 | nidx = tree->root; | |
177 | if (!nidx) | |
178 | return -ENOENT; | |
179 | height = tree->depth; | |
180 | res = 0; | |
181 | parent = 0; | |
182 | for (;;) { | |
183 | bnode = hfs_bnode_find(tree, nidx); | |
184 | if (IS_ERR(bnode)) { | |
185 | res = PTR_ERR(bnode); | |
186 | bnode = NULL; | |
187 | break; | |
188 | } | |
189 | if (bnode->height != height) | |
190 | goto invalid; | |
191 | if (bnode->type != (--height ? HFS_NODE_INDEX : HFS_NODE_LEAF)) | |
192 | goto invalid; | |
193 | bnode->parent = parent; | |
194 | ||
324ef39a | 195 | res = __hfs_brec_find(bnode, fd, do_key_compare); |
1da177e4 LT |
196 | if (!height) |
197 | break; | |
198 | if (fd->record < 0) | |
199 | goto release; | |
200 | ||
201 | parent = nidx; | |
202 | hfs_bnode_read(bnode, &data, fd->entryoffset, 4); | |
203 | nidx = be32_to_cpu(data); | |
204 | hfs_bnode_put(bnode); | |
205 | } | |
206 | fd->bnode = bnode; | |
207 | return res; | |
208 | ||
209 | invalid: | |
d6142673 | 210 | pr_err("inconsistency in B*Tree (%d,%d,%d,%u,%u)\n", |
1da177e4 LT |
211 | height, bnode->height, bnode->type, nidx, parent); |
212 | res = -EIO; | |
213 | release: | |
214 | hfs_bnode_put(bnode); | |
215 | return res; | |
216 | } | |
217 | ||
218 | int hfs_brec_read(struct hfs_find_data *fd, void *rec, int rec_len) | |
219 | { | |
220 | int res; | |
221 | ||
324ef39a | 222 | res = hfs_brec_find(fd, hfs_find_rec_by_key); |
1da177e4 LT |
223 | if (res) |
224 | return res; | |
225 | if (fd->entrylength > rec_len) | |
226 | return -EINVAL; | |
227 | hfs_bnode_read(fd->bnode, rec, fd->entryoffset, fd->entrylength); | |
228 | return 0; | |
229 | } | |
230 | ||
231 | int hfs_brec_goto(struct hfs_find_data *fd, int cnt) | |
232 | { | |
233 | struct hfs_btree *tree; | |
234 | struct hfs_bnode *bnode; | |
235 | int idx, res = 0; | |
236 | u16 off, len, keylen; | |
237 | ||
238 | bnode = fd->bnode; | |
239 | tree = bnode->tree; | |
240 | ||
241 | if (cnt < 0) { | |
242 | cnt = -cnt; | |
243 | while (cnt > fd->record) { | |
244 | cnt -= fd->record + 1; | |
245 | fd->record = bnode->num_recs - 1; | |
246 | idx = bnode->prev; | |
247 | if (!idx) { | |
248 | res = -ENOENT; | |
249 | goto out; | |
250 | } | |
251 | hfs_bnode_put(bnode); | |
252 | bnode = hfs_bnode_find(tree, idx); | |
253 | if (IS_ERR(bnode)) { | |
254 | res = PTR_ERR(bnode); | |
255 | bnode = NULL; | |
256 | goto out; | |
257 | } | |
258 | } | |
259 | fd->record -= cnt; | |
260 | } else { | |
261 | while (cnt >= bnode->num_recs - fd->record) { | |
262 | cnt -= bnode->num_recs - fd->record; | |
263 | fd->record = 0; | |
264 | idx = bnode->next; | |
265 | if (!idx) { | |
266 | res = -ENOENT; | |
267 | goto out; | |
268 | } | |
269 | hfs_bnode_put(bnode); | |
270 | bnode = hfs_bnode_find(tree, idx); | |
271 | if (IS_ERR(bnode)) { | |
272 | res = PTR_ERR(bnode); | |
273 | bnode = NULL; | |
274 | goto out; | |
275 | } | |
276 | } | |
277 | fd->record += cnt; | |
278 | } | |
279 | ||
280 | len = hfs_brec_lenoff(bnode, fd->record, &off); | |
281 | keylen = hfs_brec_keylen(bnode, fd->record); | |
9250f925 ES |
282 | if (keylen == 0) { |
283 | res = -EINVAL; | |
284 | goto out; | |
285 | } | |
1da177e4 LT |
286 | fd->keyoffset = off; |
287 | fd->keylength = keylen; | |
288 | fd->entryoffset = off + keylen; | |
289 | fd->entrylength = len - keylen; | |
290 | hfs_bnode_read(bnode, fd->key, off, keylen); | |
291 | out: | |
292 | fd->bnode = bnode; | |
293 | return res; | |
294 | } |