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
add_nondir(struct dentry * dentry,struct inode * inode)10 static 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
minix_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)22 static 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(dir->i_sb)->s_namelen)
28 return ERR_PTR(-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
minix_mknod(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,dev_t rdev)36 static 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(rdev))
42 return -EINVAL;
43
44 inode = minix_new_inode(dir, mode);
45 if (IS_ERR(inode))
46 return PTR_ERR(inode);
47
48 minix_set_inode(inode, rdev);
49 mark_inode_dirty(inode);
50 return add_nondir(dentry, inode);
51 }
52
minix_tmpfile(struct mnt_idmap * idmap,struct inode * dir,struct file * file,umode_t mode)53 static 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(inode))
59 return finish_open_simple(file, PTR_ERR(inode));
60 minix_set_inode(inode, 0);
61 mark_inode_dirty(inode);
62 d_tmpfile(file, inode);
63 return finish_open_simple(file, 0);
64 }
65
minix_create(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)66 static int minix_create(struct mnt_idmap *idmap, struct inode *dir,
67 struct dentry *dentry, umode_t mode, bool excl)
68 {
69 return minix_mknod(&nop_mnt_idmap, dir, dentry, mode, 0);
70 }
71
minix_symlink(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,const char * symname)72 static 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(inode))
84 return PTR_ERR(inode);
85
86 minix_set_inode(inode, 0);
87 err = page_symlink(inode, symname, 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
minix_link(struct dentry * old_dentry,struct inode * dir,struct dentry * dentry)96 static int minix_link(struct dentry * old_dentry, struct inode * dir,
97 struct dentry *dentry)
98 {
99 struct inode *inode = d_inode(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
minix_mkdir(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode)107 static 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(inode))
115 return PTR_ERR(inode);
116
117 inode_inc_link_count(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);
130 out:
131 return err;
132
133 out_fail:
134 inode_dec_link_count(inode);
135 inode_dec_link_count(inode);
136 iput(inode);
137 inode_dec_link_count(dir);
138 goto out;
139 }
140
minix_unlink(struct inode * dir,struct dentry * dentry)141 static 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 de = minix_find_entry(dentry, &folio);
149 if (!de)
150 return -ENOENT;
151 err = minix_delete_entry(de, folio);
152 folio_release_kmap(folio, de);
153
154 if (err)
155 return err;
156 inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
157 inode_dec_link_count(inode);
158 return 0;
159 }
160
minix_rmdir(struct inode * dir,struct dentry * dentry)161 static 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(dir);
170 inode_dec_link_count(inode);
171 }
172 }
173 return err;
174 }
175
minix_rename(struct mnt_idmap * idmap,struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry,unsigned int flags)176 static 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(old_dentry);
182 struct inode * new_inode = d_inode(new_dentry);
183 struct folio * dir_folio = NULL;
184 struct minix_dir_entry * dir_de = NULL;
185 struct folio *old_folio;
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_folio);
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_folio);
199 if (!dir_de)
200 goto out_old;
201 }
202
203 if (new_inode) {
204 struct folio *new_folio;
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_folio);
213 if (!new_de)
214 goto out_dir;
215 err = minix_set_link(new_de, new_folio, old_inode);
216 folio_release_kmap(new_folio, new_de);
217 if (err)
218 goto out_dir;
219 inode_set_ctime_current(new_inode);
220 if (dir_de)
221 drop_nlink(new_inode);
222 inode_dec_link_count(new_inode);
223 } else {
224 err = minix_add_link(new_dentry, old_inode);
225 if (err)
226 goto out_dir;
227 if (dir_de)
228 inode_inc_link_count(new_dir);
229 }
230
231 err = minix_delete_entry(old_de, old_folio);
232 if (err)
233 goto out_dir;
234
235 mark_inode_dirty(old_inode);
236
237 if (dir_de) {
238 err = minix_set_link(dir_de, dir_folio, new_dir);
239 if (!err)
240 inode_dec_link_count(old_dir);
241 }
242 out_dir:
243 if (dir_de)
244 folio_release_kmap(dir_folio, dir_de);
245 out_old:
246 folio_release_kmap(old_folio, old_de);
247 out:
248 return err;
249 }
250
251 /*
252 * directories can handle most operations...
253 */
254 const struct inode_operations minix_dir_inode_operations = {
255 .create = minix_create,
256 .lookup = minix_lookup,
257 .link = minix_link,
258 .unlink = minix_unlink,
259 .symlink = minix_symlink,
260 .mkdir = minix_mkdir,
261 .rmdir = minix_rmdir,
262 .mknod = minix_mknod,
263 .rename = minix_rename,
264 .getattr = minix_getattr,
265 .tmpfile = minix_tmpfile,
266 };
267