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 int 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 PTR_ERR(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;
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 page * page;
145 struct minix_dir_entry * de;
146 int err;
147
148 de = minix_find_entry(dentry, &page);
149 if (!de)
150 return -ENOENT;
151 err = minix_delete_entry(de, page);
152 unmap_and_put_page(page, addr: de);
153
154 if (err)
155 return err;
156 inode_set_ctime_to_ts(inode, ts: inode_get_ctime(inode: dir));
157 inode_dec_link_count(inode);
158 return 0;
159}
160
161static int minix_rmdir(struct inode * dir, struct dentry *dentry)
162{
163 struct inode * inode = d_inode(dentry);
164 int err = -ENOTEMPTY;
165
166 if (minix_empty_dir(inode)) {
167 err = minix_unlink(dir, dentry);
168 if (!err) {
169 inode_dec_link_count(inode: dir);
170 inode_dec_link_count(inode);
171 }
172 }
173 return err;
174}
175
176static int minix_rename(struct mnt_idmap *idmap,
177 struct inode *old_dir, struct dentry *old_dentry,
178 struct inode *new_dir, struct dentry *new_dentry,
179 unsigned int flags)
180{
181 struct inode * old_inode = d_inode(dentry: old_dentry);
182 struct inode * new_inode = d_inode(dentry: new_dentry);
183 struct page * dir_page = NULL;
184 struct minix_dir_entry * dir_de = NULL;
185 struct page * old_page;
186 struct minix_dir_entry * old_de;
187 int err = -ENOENT;
188
189 if (flags & ~RENAME_NOREPLACE)
190 return -EINVAL;
191
192 old_de = minix_find_entry(old_dentry, &old_page);
193 if (!old_de)
194 goto out;
195
196 if (S_ISDIR(old_inode->i_mode)) {
197 err = -EIO;
198 dir_de = minix_dotdot(old_inode, &dir_page);
199 if (!dir_de)
200 goto out_old;
201 }
202
203 if (new_inode) {
204 struct page * new_page;
205 struct minix_dir_entry * new_de;
206
207 err = -ENOTEMPTY;
208 if (dir_de && !minix_empty_dir(new_inode))
209 goto out_dir;
210
211 err = -ENOENT;
212 new_de = minix_find_entry(new_dentry, &new_page);
213 if (!new_de)
214 goto out_dir;
215 err = minix_set_link(de: new_de, page: new_page, inode: old_inode);
216 kunmap(page: new_page);
217 put_page(page: new_page);
218 if (err)
219 goto out_dir;
220 inode_set_ctime_current(inode: new_inode);
221 if (dir_de)
222 drop_nlink(inode: new_inode);
223 inode_dec_link_count(inode: new_inode);
224 } else {
225 err = minix_add_link(new_dentry, old_inode);
226 if (err)
227 goto out_dir;
228 if (dir_de)
229 inode_inc_link_count(inode: new_dir);
230 }
231
232 err = minix_delete_entry(old_de, old_page);
233 if (err)
234 goto out_dir;
235
236 mark_inode_dirty(inode: old_inode);
237
238 if (dir_de) {
239 err = minix_set_link(de: dir_de, page: dir_page, inode: new_dir);
240 if (!err)
241 inode_dec_link_count(inode: old_dir);
242 }
243out_dir:
244 if (dir_de)
245 unmap_and_put_page(page: dir_page, addr: dir_de);
246out_old:
247 unmap_and_put_page(page: old_page, addr: old_de);
248out:
249 return err;
250}
251
252/*
253 * directories can handle most operations...
254 */
255const struct inode_operations minix_dir_inode_operations = {
256 .create = minix_create,
257 .lookup = minix_lookup,
258 .link = minix_link,
259 .unlink = minix_unlink,
260 .symlink = minix_symlink,
261 .mkdir = minix_mkdir,
262 .rmdir = minix_rmdir,
263 .mknod = minix_mknod,
264 .rename = minix_rename,
265 .getattr = minix_getattr,
266 .tmpfile = minix_tmpfile,
267};
268

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