hfsplus: add support of manipulation by attributes file
[~shefty/rdma-dev.git] / fs / hfsplus / bfind.c
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;
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();
39         }
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);
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;
51 }
52
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)
92 {
93         int cmpval;
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 {
112         u16 off, len, keylen;
113         int rec;
114         int b, e;
115         int res;
116
117         if (!rec_found)
118                 BUG();
119
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;
130                 }
131                 hfs_bnode_read(bnode, fd->key, off, keylen);
132                 if (rec_found(bnode, fd, &b, &e, &rec)) {
133                         res = 0;
134                         goto done;
135                 }
136         } while (b <= e);
137
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;
144                 }
145                 hfs_bnode_read(bnode, fd->key, off, keylen);
146         }
147
148 done:
149         fd->record = e;
150         fd->keyoffset = off;
151         fd->keylength = keylen;
152         fd->entryoffset = off + keylen;
153         fd->entrylength = len - keylen;
154
155 fail:
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 */
161 int hfs_brec_find(struct hfs_find_data *fd, search_strategy_t do_key_compare)
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
192                 res = __hfs_brec_find(bnode, fd, do_key_compare);
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:
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;
213 }
214
215 int hfs_brec_read(struct hfs_find_data *fd, void *rec, int rec_len)
216 {
217         int res;
218
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;
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);
279         if (keylen == 0) {
280                 res = -EINVAL;
281                 goto out;
282         }
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 }