File: /usr/src/linux/fs/adfs/dir.c
1 /*
2 * linux/fs/adfs/dir.c
3 *
4 * Copyright (C) 1999-2000 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Common directory handling for ADFS
11 */
12 #include <linux/config.h>
13 #include <linux/version.h>
14 #include <linux/errno.h>
15 #include <linux/fs.h>
16 #include <linux/adfs_fs.h>
17 #include <linux/sched.h>
18 #include <linux/stat.h>
19 #include <linux/spinlock.h>
20
21 #include "adfs.h"
22
23 /*
24 * For future. This should probably be per-directory.
25 */
26 static rwlock_t adfs_dir_lock;
27
28 static int
29 adfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
30 {
31 struct inode *inode = filp->f_dentry->d_inode;
32 struct super_block *sb = inode->i_sb;
33 struct adfs_dir_ops *ops = sb->u.adfs_sb.s_dir;
34 struct object_info obj;
35 struct adfs_dir dir;
36 int ret = 0;
37
38 if (filp->f_pos >> 32)
39 goto out;
40
41 ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
42 if (ret)
43 goto out;
44
45 switch ((unsigned long)filp->f_pos) {
46 case 0:
47 if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
48 goto free_out;
49 filp->f_pos += 1;
50
51 case 1:
52 if (filldir(dirent, "..", 2, 1, dir.parent_id, DT_DIR) < 0)
53 goto free_out;
54 filp->f_pos += 1;
55
56 default:
57 break;
58 }
59
60 read_lock(&adfs_dir_lock);
61
62 ret = ops->setpos(&dir, filp->f_pos - 2);
63 if (ret)
64 goto unlock_out;
65 while (ops->getnext(&dir, &obj) == 0) {
66 if (filldir(dirent, obj.name, obj.name_len,
67 filp->f_pos, obj.file_id, DT_UNKNOWN) < 0)
68 goto unlock_out;
69 filp->f_pos += 1;
70 }
71
72 unlock_out:
73 read_unlock(&adfs_dir_lock);
74
75 free_out:
76 ops->free(&dir);
77
78 out:
79 return ret;
80 }
81
82 int
83 adfs_dir_update(struct super_block *sb, struct object_info *obj)
84 {
85 int ret = -EINVAL;
86 #ifdef CONFIG_ADFS_FS_RW
87 struct adfs_dir_ops *ops = sb->u.adfs_sb.s_dir;
88 struct adfs_dir dir;
89
90 printk(KERN_INFO "adfs_dir_update: object %06X in dir %06X\n",
91 obj->file_id, obj->parent_id);
92
93 if (!ops->update) {
94 ret = -EINVAL;
95 goto out;
96 }
97
98 ret = ops->read(sb, obj->parent_id, 0, &dir);
99 if (ret)
100 goto out;
101
102 write_lock(&adfs_dir_lock);
103 ret = ops->update(&dir, obj);
104 write_unlock(&adfs_dir_lock);
105
106 ops->free(&dir);
107 out:
108 #endif
109 return ret;
110 }
111
112 static int
113 adfs_match(struct qstr *name, struct object_info *obj)
114 {
115 int i;
116
117 if (name->len != obj->name_len)
118 return 0;
119
120 for (i = 0; i < name->len; i++) {
121 char c1, c2;
122
123 c1 = name->name[i];
124 c2 = obj->name[i];
125
126 if (c1 >= 'A' && c1 <= 'Z')
127 c1 += 'a' - 'A';
128 if (c2 >= 'A' && c2 <= 'Z')
129 c2 += 'a' - 'A';
130
131 if (c1 != c2)
132 return 0;
133 }
134 return 1;
135 }
136
137 static int
138 adfs_dir_lookup_byname(struct inode *inode, struct qstr *name, struct object_info *obj)
139 {
140 struct super_block *sb = inode->i_sb;
141 struct adfs_dir_ops *ops = sb->u.adfs_sb.s_dir;
142 struct adfs_dir dir;
143 int ret;
144
145 ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
146 if (ret)
147 goto out;
148
149 if (inode->u.adfs_i.parent_id != dir.parent_id) {
150 adfs_error(sb, "parent directory changed under me! (%lx but got %lx)\n",
151 inode->u.adfs_i.parent_id, dir.parent_id);
152 ret = -EIO;
153 goto free_out;
154 }
155
156 obj->parent_id = inode->i_ino;
157
158 /*
159 * '.' is handled by reserved_lookup() in fs/namei.c
160 */
161 if (name->len == 2 && name->name[0] == '.' && name->name[1] == '.') {
162 /*
163 * Currently unable to fill in the rest of 'obj',
164 * but this is better than nothing. We need to
165 * ascend one level to find it's parent.
166 */
167 obj->name_len = 0;
168 obj->file_id = obj->parent_id;
169 goto free_out;
170 }
171
172 read_lock(&adfs_dir_lock);
173
174 ret = ops->setpos(&dir, 0);
175 if (ret)
176 goto unlock_out;
177
178 ret = -ENOENT;
179 while (ops->getnext(&dir, obj) == 0) {
180 if (adfs_match(name, obj)) {
181 ret = 0;
182 break;
183 }
184 }
185
186 unlock_out:
187 read_unlock(&adfs_dir_lock);
188
189 free_out:
190 ops->free(&dir);
191 out:
192 return ret;
193 }
194
195 struct file_operations adfs_dir_operations = {
196 read: generic_read_dir,
197 readdir: adfs_readdir,
198 fsync: file_fsync,
199 };
200
201 static int
202 adfs_hash(struct dentry *parent, struct qstr *qstr)
203 {
204 const unsigned int name_len = parent->d_sb->u.adfs_sb.s_namelen;
205 const unsigned char *name;
206 unsigned long hash;
207 int i;
208
209 if (qstr->len < name_len)
210 return 0;
211
212 /*
213 * Truncate the name in place, avoids
214 * having to define a compare function.
215 */
216 qstr->len = i = name_len;
217 name = qstr->name;
218 hash = init_name_hash();
219 while (i--) {
220 char c;
221
222 c = *name++;
223 if (c >= 'A' && c <= 'Z')
224 c += 'a' - 'A';
225
226 hash = partial_name_hash(c, hash);
227 }
228 qstr->hash = end_name_hash(hash);
229
230 return 0;
231 }
232
233 /*
234 * Compare two names, taking note of the name length
235 * requirements of the underlying filesystem.
236 */
237 static int
238 adfs_compare(struct dentry *parent, struct qstr *entry, struct qstr *name)
239 {
240 int i;
241
242 if (entry->len != name->len)
243 return 1;
244
245 for (i = 0; i < name->len; i++) {
246 char a, b;
247
248 a = entry->name[i];
249 b = name->name[i];
250
251 if (a >= 'A' && a <= 'Z')
252 a += 'a' - 'A';
253 if (b >= 'A' && b <= 'Z')
254 b += 'a' - 'A';
255
256 if (a != b)
257 return 1;
258 }
259 return 0;
260 }
261
262 struct dentry_operations adfs_dentry_operations = {
263 d_hash: adfs_hash,
264 d_compare: adfs_compare,
265 };
266
267 struct dentry *adfs_lookup(struct inode *dir, struct dentry *dentry)
268 {
269 struct inode *inode = NULL;
270 struct object_info obj;
271 int error;
272
273 dentry->d_op = &adfs_dentry_operations;
274 error = adfs_dir_lookup_byname(dir, &dentry->d_name, &obj);
275 if (error == 0) {
276 error = -EACCES;
277 /*
278 * This only returns NULL if get_empty_inode
279 * fails.
280 */
281 inode = adfs_iget(dir->i_sb, &obj);
282 if (inode)
283 error = 0;
284 }
285 d_add(dentry, inode);
286 return ERR_PTR(error);
287 }
288
289 /*
290 * directories can handle most operations...
291 */
292 struct inode_operations adfs_dir_inode_operations = {
293 lookup: adfs_lookup,
294 setattr: adfs_notify_change,
295 };
296