1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/minix/namei.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 */
7
8#include "minix.h"
9
10static int add_nondir(struct dentry *dentry, struct inode *inode)
11{
12 int err = minix_add_link(dentry, inode);
13 if (!err) {
14 d_instantiate(dentry, inode);
15 return 0;
16 }
17 inode_dec_link_count(inode);
18 iput(inode);
19 return err;
20}
21
22static struct dentry *minix_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
23{
24 struct inode * inode = NULL;
25 ino_t ino;
26
27 if (dentry->d_name.len > minix_sb(sb: dir->i_sb)->s_namelen)
28 return ERR_PTR(error: -ENAMETOOLONG);
29
30 ino = minix_inode_by_name(dentry);
31 if (ino)
32 inode = minix_iget(dir->i_sb, ino);
33 return d_splice_alias(inode, dentry);
34}
35
36static int minix_mknod(struct mnt_idmap *idmap, struct inode *dir,
37 struct dentry *dentry, umode_t mode, dev_t rdev)
38{
39 struct inode *inode;
40
41 if (!old_valid_dev(dev: rdev))
42 return -EINVAL;
43
44 inode = minix_new_inode(dir, mode);
45 if (IS_ERR(ptr: inode))
46 return PTR_ERR(ptr: inode);
47
48 minix_set_inode(inode, rdev);
49 mark_inode_dirty(inode);
50 return add_nondir(dentry, inode);
51}
52
53static int minix_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
54 struct file *file, umode_t mode)
55{
56 struct inode *inode = minix_new_inode(dir, mode);
57
58 if (IS_ERR(ptr: inode))
59 return finish_open_simple(file, error: PTR_ERR(ptr: inode));
60 minix_set_inode(inode, 0);
61 mark_inode_dirty(inode);
62 d_tmpfile(file, inode);
63 return finish_open_simple(file, error: 0);
64}
65
66static int minix_create(struct mnt_idmap *idmap, struct inode *dir,
67 struct dentry *dentry, umode_t mode, bool excl)
68{
69 return minix_mknod(idmap: &nop_mnt_idmap, dir, dentry, mode, rdev: 0);
70}
71
72static int minix_symlink(struct mnt_idmap *idmap, struct inode *dir,
73 struct dentry *dentry, const char *symname)
74{
75 int i = strlen(symname)+1;
76 struct inode * inode;
77 int err;
78
79 if (i > dir->i_sb->s_blocksize)
80 return -ENAMETOOLONG;
81
82 inode = minix_new_inode(dir, S_IFLNK | 0777);
83 if (IS_ERR(ptr: inode))
84 return PTR_ERR(ptr: inode);
85
86 minix_set_inode(inode, 0);
87 err = page_symlink(inode, symname, len: i);
88 if (unlikely(err)) {
89 inode_dec_link_count(inode);
90 iput(inode);
91 return err;
92 }
93 return add_nondir(dentry, inode);
94}
95
96static int minix_link(struct dentry * old_dentry, struct inode * dir,
97 struct dentry *dentry)
98{
99 struct inode *inode = d_inode(dentry: old_dentry);
100
101 inode_set_ctime_current(inode);
102 inode_inc_link_count(inode);
103 ihold(inode);
104 return add_nondir(dentry, inode);
105}
106
107static struct dentry *minix_mkdir(struct mnt_idmap *idmap, struct inode *dir,
108 struct dentry *dentry, umode_t mode)
109{
110 struct inode * inode;
111 int err;
112
113 inode = minix_new_inode(dir, S_IFDIR | mode);
114 if (IS_ERR(ptr: inode))
115 return ERR_CAST(ptr: inode);
116
117 inode_inc_link_count(inode: dir);
118 minix_set_inode(inode, 0);
119 inode_inc_link_count(inode);
120
121 err = minix_make_empty(inode, dir);
122 if (err)
123 goto out_fail;
124
125 err = minix_add_link(dentry, inode);
126 if (err)
127 goto out_fail;
128
129 d_instantiate(dentry, inode);
130out:
131 return ERR_PTR(error: err);
132
133out_fail:
134 inode_dec_link_count(inode);
135 inode_dec_link_count(inode);
136 iput(inode);
137 inode_dec_link_count(inode: dir);
138 goto out;
139}
140
141static int minix_unlink(struct inode * dir, struct dentry *dentry)
142{
143 struct inode * inode = d_inode(dentry);
144 struct folio *folio;
145 struct minix_dir_entry * de;
146 int err;
147
148 if (inode->i_nlink == 0) {
149 minix_error_inode(inode, "inode has corrupted nlink");
150 return -EFSCORRUPTED;
151 }
152
153 de = minix_find_entry(dentry, &folio);
154 if (!de)
155 return -ENOENT;
156 err = minix_delete_entry(de, folio);
157 folio_release_kmap(folio, addr: de);
158
159 if (err)
160 return err;
161 inode_set_ctime_to_ts(inode, ts: inode_get_ctime(inode: dir));
162 inode_dec_link_count(inode);
163 return 0;
164}
165
166static int minix_rmdir(struct inode * dir, struct dentry *dentry)
167{
168 struct inode * inode = d_inode(dentry);
169 int err = -EFSCORRUPTED;
170
171 if (dir->i_nlink <= 2) {
172 minix_error_inode(dir, "inode has corrupted nlink");
173 goto out;
174 }
175
176 err = -ENOTEMPTY;
177 if (!minix_empty_dir(inode))
178 goto out;
179
180 err = minix_unlink(dir, dentry);
181 if (!err) {
182 inode_dec_link_count(inode: dir);
183 inode_dec_link_count(inode);
184 }
185
186out:
187 return err;
188}
189
190static int minix_rename(struct mnt_idmap *idmap,
191 struct inode *old_dir, struct dentry *old_dentry,
192 struct inode *new_dir, struct dentry *new_dentry,
193 unsigned int flags)
194{
195 struct inode * old_inode = d_inode(dentry: old_dentry);
196 struct inode * new_inode = d_inode(dentry: new_dentry);
197 struct folio * dir_folio = NULL;
198 struct minix_dir_entry * dir_de = NULL;
199 struct folio *old_folio;
200 struct minix_dir_entry * old_de;
201 int err = -ENOENT;
202
203 if (flags & ~RENAME_NOREPLACE)
204 return -EINVAL;
205
206 old_de = minix_find_entry(old_dentry, &old_folio);
207 if (!old_de)
208 goto out;
209
210 if (S_ISDIR(old_inode->i_mode)) {
211 err = -EIO;
212 dir_de = minix_dotdot(old_inode, &dir_folio);
213 if (!dir_de)
214 goto out_old;
215 }
216
217 if (new_inode) {
218 struct folio *new_folio;
219 struct minix_dir_entry * new_de;
220
221 err = -ENOTEMPTY;
222 if (dir_de && !minix_empty_dir(new_inode))
223 goto out_dir;
224
225 err = -EFSCORRUPTED;
226 if (new_inode->i_nlink == 0 || (dir_de && new_inode->i_nlink != 2)) {
227 minix_error_inode(new_inode, "inode has corrupted nlink");
228 goto out_dir;
229 }
230
231 if (dir_de && old_dir->i_nlink <= 2) {
232 minix_error_inode(old_dir, "inode has corrupted nlink");
233 goto out_dir;
234 }
235
236 err = -ENOENT;
237 new_de = minix_find_entry(new_dentry, &new_folio);
238 if (!new_de)
239 goto out_dir;
240 err = minix_set_link(de: new_de, folio: new_folio, inode: old_inode);
241 folio_release_kmap(folio: new_folio, addr: new_de);
242 if (err)
243 goto out_dir;
244 inode_set_ctime_current(inode: new_inode);
245 if (dir_de)
246 drop_nlink(inode: new_inode);
247 inode_dec_link_count(inode: new_inode);
248 } else {
249 err = minix_add_link(new_dentry, old_inode);
250 if (err)
251 goto out_dir;
252 if (dir_de)
253 inode_inc_link_count(inode: new_dir);
254 }
255
256 err = minix_delete_entry(old_de, old_folio);
257 if (err)
258 goto out_dir;
259
260 mark_inode_dirty(inode: old_inode);
261
262 if (dir_de) {
263 err = minix_set_link(de: dir_de, folio: dir_folio, inode: new_dir);
264 if (!err)
265 inode_dec_link_count(inode: old_dir);
266 }
267out_dir:
268 if (dir_de)
269 folio_release_kmap(folio: dir_folio, addr: dir_de);
270out_old:
271 folio_release_kmap(folio: old_folio, addr: old_de);
272out:
273 return err;
274}
275
276/*
277 * directories can handle most operations...
278 */
279const struct inode_operations minix_dir_inode_operations = {
280 .create = minix_create,
281 .lookup = minix_lookup,
282 .link = minix_link,
283 .unlink = minix_unlink,
284 .symlink = minix_symlink,
285 .mkdir = minix_mkdir,
286 .rmdir = minix_rmdir,
287 .mknod = minix_mknod,
288 .rename = minix_rename,
289 .getattr = minix_getattr,
290 .tmpfile = minix_tmpfile,
291};
292

source code of linux/fs/minix/namei.c