Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
[linux-2.6/libata-dev.git] / fs / hfsplus / bfind.c
blobd73c98d1ee99268e16cdd4e6a81a1fd1700c8435
1 /*
2 * linux/fs/hfsplus/bfind.c
4 * Copyright (C) 2001
5 * Brad Boyer (flar@allandria.com)
6 * (C) 2003 Ardis Technologies <roman@ardistech.com>
8 * Search routines for btrees
9 */
11 #include <linux/slab.h>
12 #include "hfsplus_fs.h"
14 int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
16 void *ptr;
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;
25 dprint(DBG_BNODE_REFS, "find_init: %d (%p)\n",
26 tree->cnid, __builtin_return_address(0));
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();
40 return 0;
43 void hfs_find_exit(struct hfs_find_data *fd)
45 hfs_bnode_put(fd->bnode);
46 kfree(fd->search_key);
47 dprint(DBG_BNODE_REFS, "find_exit: %d (%p)\n",
48 fd->tree->cnid, __builtin_return_address(0));
49 mutex_unlock(&fd->tree->tree_lock);
50 fd->tree = NULL;
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)
59 __be32 cur_cnid, search_cnid;
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();
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;
84 return 0;
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)
93 int cmpval;
95 cmpval = bnode->tree->keycmp(fd->key, fd->search_key);
96 if (!cmpval) {
97 (*end) = (*cur_rec);
98 return 1;
100 if (cmpval < 0)
101 (*begin) = (*cur_rec) + 1;
102 else
103 *(end) = (*cur_rec) - 1;
105 return 0;
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)
112 u16 off, len, keylen;
113 int rec;
114 int b, e;
115 int res;
117 if (!rec_found)
118 BUG();
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);
127 if (keylen == 0) {
128 res = -EINVAL;
129 goto fail;
131 hfs_bnode_read(bnode, fd->key, off, keylen);
132 if (rec_found(bnode, fd, &b, &e, &rec)) {
133 res = 0;
134 goto done;
136 } while (b <= e);
138 if (rec != e && e >= 0) {
139 len = hfs_brec_lenoff(bnode, e, &off);
140 keylen = hfs_brec_keylen(bnode, e);
141 if (keylen == 0) {
142 res = -EINVAL;
143 goto fail;
145 hfs_bnode_read(bnode, fd->key, off, keylen);
148 done:
149 fd->record = e;
150 fd->keyoffset = off;
151 fd->keylength = keylen;
152 fd->entryoffset = off + keylen;
153 fd->entrylength = len - keylen;
155 fail:
156 return res;
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 */
161 int hfs_brec_find(struct hfs_find_data *fd, search_strategy_t do_key_compare)
163 struct hfs_btree *tree;
164 struct hfs_bnode *bnode;
165 u32 nidx, parent;
166 __be32 data;
167 int height, res;
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;
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;
192 res = __hfs_brec_find(bnode, fd, do_key_compare);
193 if (!height)
194 break;
195 if (fd->record < 0)
196 goto release;
198 parent = nidx;
199 hfs_bnode_read(bnode, &data, fd->entryoffset, 4);
200 nidx = be32_to_cpu(data);
201 hfs_bnode_put(bnode);
203 fd->bnode = bnode;
204 return res;
206 invalid:
207 printk(KERN_ERR "hfs: inconsistency in B*Tree (%d,%d,%d,%u,%u)\n",
208 height, bnode->height, bnode->type, nidx, parent);
209 res = -EIO;
210 release:
211 hfs_bnode_put(bnode);
212 return res;
215 int hfs_brec_read(struct hfs_find_data *fd, void *rec, int rec_len)
217 int res;
219 res = hfs_brec_find(fd, hfs_find_rec_by_key);
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;
228 int hfs_brec_goto(struct hfs_find_data *fd, int cnt)
230 struct hfs_btree *tree;
231 struct hfs_bnode *bnode;
232 int idx, res = 0;
233 u16 off, len, keylen;
235 bnode = fd->bnode;
236 tree = bnode->tree;
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;
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;
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;
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;
274 fd->record += cnt;
277 len = hfs_brec_lenoff(bnode, fd->record, &off);
278 keylen = hfs_brec_keylen(bnode, fd->record);
279 if (keylen == 0) {
280 res = -EINVAL;
281 goto out;
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;