1 /*
2 * linux/fs/minix/namei.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7 #include "minix.h"
8
9 static inline void inc_count(struct inode *inode)
10 {
11 inode->i_nlink++;
12 mark_inode_dirty(inode);
13 }
14
15 static inline void dec_count(struct inode *inode)
16 {
17 inode->i_nlink--;
18 mark_inode_dirty(inode);
19 }
20
21 static int add_nondir(struct dentry *dentry, struct inode *inode)
22 {
23 int err = minix_add_link(dentry, inode);
24 if (!err) {
25 d_instantiate(dentry, inode);
26 return 0;
27 }
28 dec_count(inode);
29 iput(inode);
30 return err;
31 }
32
33 static int minix_hash(struct dentry *dentry, struct qstr *qstr)
34 {
35 unsigned long hash;
36 int i;
37 const unsigned char *name;
38
39 i = minix_sb(dentry->d_inode->i_sb)->s_namelen;
40 if (i >= qstr->len)
41 return 0;
42 /* Truncate the name in place, avoids having to define a compare
43 function. */
44 qstr->len = i;
45 name = qstr->name;
46 hash = init_name_hash();
47 while (i--)
48 hash = partial_name_hash(*name++, hash);
49 qstr->hash = end_name_hash(hash);
50 return 0;
51 }
52
53 struct dentry_operations minix_dentry_operations = {
54 .d_hash = minix_hash,
55 };
56
57 static struct dentry *minix_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
58 {
59 struct inode * inode = NULL;
60 ino_t ino;
61
62 dentry->d_op = dir->i_sb->s_root->d_op;
63
64 if (dentry->d_name.len > minix_sb(dir->i_sb)->s_namelen)
65 return ERR_PTR(-ENAMETOOLONG);
66
67 ino = minix_inode_by_name(dentry);
68 if (ino) {
69 inode = iget(dir->i_sb, ino);
70
71 if (!inode)
72 return ERR_PTR(-EACCES);
73 }
74 d_add(dentry, inode);
75 return NULL;
76 }
77
78 static int minix_mknod(struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
79 {
80 int error;
81 struct inode *inode;
82
83 if (!old_valid_dev(rdev))
84 return -EINVAL;
85
86 inode = minix_new_inode(dir, &error);
87
88 if (inode) {
89 inode->i_mode = mode;
90 minix_set_inode(inode, rdev);
91 mark_inode_dirty(inode);
92 error = add_nondir(dentry, inode);
93 }
94 return error;
95 }
96
97 static int minix_create(struct inode * dir, struct dentry *dentry, int mode,
98 struct nameidata *nd)
99 {
100 return minix_mknod(dir, dentry, mode, 0);
101 }
102
103 static int minix_symlink(struct inode * dir, struct dentry *dentry,
104 const char * symname)
105 {
106 int err = -ENAMETOOLONG;
107 int i = strlen(symname)+1;
108 struct inode * inode;
109
110 if (i > dir->i_sb->s_blocksize)
111 goto out;
112
113 inode = minix_new_inode(dir, &err);
114 if (!inode)
115 goto out;
116
117 inode->i_mode = S_IFLNK | 0777;
118 minix_set_inode(inode, 0);
119 err = page_symlink(inode, symname, i);
120 if (err)
121 goto out_fail;
122
123 err = add_nondir(dentry, inode);
124 out:
125 return err;
126
127 out_fail:
128 dec_count(inode);
129 iput(inode);
130 goto out;
131 }
132
133 static int minix_link(struct dentry * old_dentry, struct inode * dir,
134 struct dentry *dentry)
135 {
136 struct inode *inode = old_dentry->d_inode;
137
138 if (inode->i_nlink >= minix_sb(inode->i_sb)->s_link_max)
139 return -EMLINK;
140
141 inode->i_ctime = CURRENT_TIME_SEC;
142 inc_count(inode);
143 atomic_inc(&inode->i_count);
144 return add_nondir(dentry, inode);
145 }
146
147 static int minix_mkdir(struct inode * dir, struct dentry *dentry, int mode)
148 {
149 struct inode * inode;
150 int err = -EMLINK;
151
152 if (dir->i_nlink >= minix_sb(dir->i_sb)->s_link_max)
153 goto out;
154
155 inc_count(dir);
156
157 inode = minix_new_inode(dir, &err);
158 if (!inode)
159 goto out_dir;
160
161 inode->i_mode = S_IFDIR | mode;
162 if (dir->i_mode & S_ISGID)
163 inode->i_mode |= S_ISGID;
164 minix_set_inode(inode, 0);
165
166 inc_count(inode);
167
168 err = minix_make_empty(inode, dir);
169 if (err)
170 goto out_fail;
171
172 err = minix_add_link(dentry, inode);
173 if (err)
174 goto out_fail;
175
176 d_instantiate(dentry, inode);
177 out:
178 return err;
179
180 out_fail:
181 dec_count(inode);
182 dec_count(inode);
183 iput(inode);
184 out_dir:
185 dec_count(dir);
186 goto out;
187 }
188
189 static int minix_unlink(struct inode * dir, struct dentry *dentry)
190 {
191 int err = -ENOENT;
192 struct inode * inode = dentry->d_inode;
193 struct page * page;
194 struct minix_dir_entry * de;
195
196 de = minix_find_entry(dentry, &page);
197 if (!de)
198 goto end_unlink;
199
200 err = minix_delete_entry(de, page);
201 if (err)
202 goto end_unlink;
203
204 inode->i_ctime = dir->i_ctime;
205 dec_count(inode);
206 end_unlink:
207 return err;
208 }
209
210 static int minix_rmdir(struct inode * dir, struct dentry *dentry)
211 {
212 struct inode * inode = dentry->d_inode;
213 int err = -ENOTEMPTY;
214
215 if (minix_empty_dir(inode)) {
216 err = minix_unlink(dir, dentry);
217 if (!err) {
218 dec_count(dir);
219 dec_count(inode);
220 }
221 }
222 return err;
223 }
224
225 static int minix_rename(struct inode * old_dir, struct dentry *old_dentry,
226 struct inode * new_dir, struct dentry *new_dentry)
227 {
228 struct minix_sb_info * info = minix_sb(old_dir->i_sb);
229 struct inode * old_inode = old_dentry->d_inode;
230 struct inode * new_inode = new_dentry->d_inode;
231 struct page * dir_page = NULL;
232 struct minix_dir_entry * dir_de = NULL;
233 struct page * old_page;
234 struct minix_dir_entry * old_de;
235 int err = -ENOENT;
236
237 old_de = minix_find_entry(old_dentry, &old_page);
238 if (!old_de)
239 goto out;
240
241 if (S_ISDIR(old_inode->i_mode)) {
242 err = -EIO;
243 dir_de = minix_dotdot(old_inode, &dir_page);
244 if (!dir_de)
245 goto out_old;
246 }
247
248 if (new_inode) {
249 struct page * new_page;
250 struct minix_dir_entry * new_de;
251
252 err = -ENOTEMPTY;
253 if (dir_de && !minix_empty_dir(new_inode))
254 goto out_dir;
255
256 err = -ENOENT;
257 new_de = minix_find_entry(new_dentry, &new_page);
258 if (!new_de)
259 goto out_dir;
260 inc_count(old_inode);
261 minix_set_link(new_de, new_page, old_inode);
262 new_inode->i_ctime = CURRENT_TIME_SEC;
263 if (dir_de)
264 new_inode->i_nlink--;
265 dec_count(new_inode);
266 } else {
267 if (dir_de) {
268 err = -EMLINK;
269 if (new_dir->i_nlink >= info->s_link_max)
270 goto out_dir;
271 }
272 inc_count(old_inode);
273 err = minix_add_link(new_dentry, old_inode);
274 if (err) {
275 dec_count(old_inode);
276 goto out_dir;
277 }
278 if (dir_de)
279 inc_count(new_dir);
280 }
281
282 minix_delete_entry(old_de, old_page);
283 dec_count(old_inode);
284
285 if (dir_de) {
286 minix_set_link(dir_de, dir_page, new_dir);
287 dec_count(old_dir);
288 }
289 return 0;
290
291 out_dir:
292 if (dir_de) {
293 kunmap(dir_page);
294 page_cache_release(dir_page);
295 }
296 out_old:
297 kunmap(old_page);
298 page_cache_release(old_page);
299 out:
300 return err;
301 }
302
303 /*
304 * directories can handle most operations...
305 */
306 struct inode_operations minix_dir_inode_operations = {
307 .create = minix_create,
308 .lookup = minix_lookup,
309 .link = minix_link,
310 .unlink = minix_unlink,
311 .symlink = minix_symlink,
312 .mkdir = minix_mkdir,
313 .rmdir = minix_rmdir,
314 .mknod = minix_mknod,
315 .rename = minix_rename,
316 .getattr = minix_getattr,
317 };
318
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