xref: /openbmc/linux/fs/minix/namei.c (revision 4800cd83)
1 /*
2  *  linux/fs/minix/namei.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  */
6 
7 #include "minix.h"
8 
9 static int add_nondir(struct dentry *dentry, struct inode *inode)
10 {
11 	int err = minix_add_link(dentry, inode);
12 	if (!err) {
13 		d_instantiate(dentry, inode);
14 		return 0;
15 	}
16 	inode_dec_link_count(inode);
17 	iput(inode);
18 	return err;
19 }
20 
21 static struct dentry *minix_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
22 {
23 	struct inode * inode = NULL;
24 	ino_t ino;
25 
26 	if (dentry->d_name.len > minix_sb(dir->i_sb)->s_namelen)
27 		return ERR_PTR(-ENAMETOOLONG);
28 
29 	ino = minix_inode_by_name(dentry);
30 	if (ino) {
31 		inode = minix_iget(dir->i_sb, ino);
32 		if (IS_ERR(inode))
33 			return ERR_CAST(inode);
34 	}
35 	d_add(dentry, inode);
36 	return NULL;
37 }
38 
39 static int minix_mknod(struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
40 {
41 	int error;
42 	struct inode *inode;
43 
44 	if (!old_valid_dev(rdev))
45 		return -EINVAL;
46 
47 	inode = minix_new_inode(dir, mode, &error);
48 
49 	if (inode) {
50 		minix_set_inode(inode, rdev);
51 		mark_inode_dirty(inode);
52 		error = add_nondir(dentry, inode);
53 	}
54 	return error;
55 }
56 
57 static int minix_create(struct inode * dir, struct dentry *dentry, int mode,
58 		struct nameidata *nd)
59 {
60 	return minix_mknod(dir, dentry, mode, 0);
61 }
62 
63 static int minix_symlink(struct inode * dir, struct dentry *dentry,
64 	  const char * symname)
65 {
66 	int err = -ENAMETOOLONG;
67 	int i = strlen(symname)+1;
68 	struct inode * inode;
69 
70 	if (i > dir->i_sb->s_blocksize)
71 		goto out;
72 
73 	inode = minix_new_inode(dir, S_IFLNK | 0777, &err);
74 	if (!inode)
75 		goto out;
76 
77 	minix_set_inode(inode, 0);
78 	err = page_symlink(inode, symname, i);
79 	if (err)
80 		goto out_fail;
81 
82 	err = add_nondir(dentry, inode);
83 out:
84 	return err;
85 
86 out_fail:
87 	inode_dec_link_count(inode);
88 	iput(inode);
89 	goto out;
90 }
91 
92 static int minix_link(struct dentry * old_dentry, struct inode * dir,
93 	struct dentry *dentry)
94 {
95 	struct inode *inode = old_dentry->d_inode;
96 
97 	if (inode->i_nlink >= minix_sb(inode->i_sb)->s_link_max)
98 		return -EMLINK;
99 
100 	inode->i_ctime = CURRENT_TIME_SEC;
101 	inode_inc_link_count(inode);
102 	ihold(inode);
103 	return add_nondir(dentry, inode);
104 }
105 
106 static int minix_mkdir(struct inode * dir, struct dentry *dentry, int mode)
107 {
108 	struct inode * inode;
109 	int err = -EMLINK;
110 
111 	if (dir->i_nlink >= minix_sb(dir->i_sb)->s_link_max)
112 		goto out;
113 
114 	inode_inc_link_count(dir);
115 
116 	inode = minix_new_inode(dir, S_IFDIR | mode, &err);
117 	if (!inode)
118 		goto out_dir;
119 
120 	minix_set_inode(inode, 0);
121 
122 	inode_inc_link_count(inode);
123 
124 	err = minix_make_empty(inode, dir);
125 	if (err)
126 		goto out_fail;
127 
128 	err = minix_add_link(dentry, inode);
129 	if (err)
130 		goto out_fail;
131 
132 	d_instantiate(dentry, inode);
133 out:
134 	return err;
135 
136 out_fail:
137 	inode_dec_link_count(inode);
138 	inode_dec_link_count(inode);
139 	iput(inode);
140 out_dir:
141 	inode_dec_link_count(dir);
142 	goto out;
143 }
144 
145 static int minix_unlink(struct inode * dir, struct dentry *dentry)
146 {
147 	int err = -ENOENT;
148 	struct inode * inode = dentry->d_inode;
149 	struct page * page;
150 	struct minix_dir_entry * de;
151 
152 	de = minix_find_entry(dentry, &page);
153 	if (!de)
154 		goto end_unlink;
155 
156 	err = minix_delete_entry(de, page);
157 	if (err)
158 		goto end_unlink;
159 
160 	inode->i_ctime = dir->i_ctime;
161 	inode_dec_link_count(inode);
162 end_unlink:
163 	return err;
164 }
165 
166 static int minix_rmdir(struct inode * dir, struct dentry *dentry)
167 {
168 	struct inode * inode = dentry->d_inode;
169 	int err = -ENOTEMPTY;
170 
171 	if (minix_empty_dir(inode)) {
172 		err = minix_unlink(dir, dentry);
173 		if (!err) {
174 			inode_dec_link_count(dir);
175 			inode_dec_link_count(inode);
176 		}
177 	}
178 	return err;
179 }
180 
181 static int minix_rename(struct inode * old_dir, struct dentry *old_dentry,
182 			   struct inode * new_dir, struct dentry *new_dentry)
183 {
184 	struct minix_sb_info * info = minix_sb(old_dir->i_sb);
185 	struct inode * old_inode = old_dentry->d_inode;
186 	struct inode * new_inode = new_dentry->d_inode;
187 	struct page * dir_page = NULL;
188 	struct minix_dir_entry * dir_de = NULL;
189 	struct page * old_page;
190 	struct minix_dir_entry * old_de;
191 	int err = -ENOENT;
192 
193 	old_de = minix_find_entry(old_dentry, &old_page);
194 	if (!old_de)
195 		goto out;
196 
197 	if (S_ISDIR(old_inode->i_mode)) {
198 		err = -EIO;
199 		dir_de = minix_dotdot(old_inode, &dir_page);
200 		if (!dir_de)
201 			goto out_old;
202 	}
203 
204 	if (new_inode) {
205 		struct page * new_page;
206 		struct minix_dir_entry * new_de;
207 
208 		err = -ENOTEMPTY;
209 		if (dir_de && !minix_empty_dir(new_inode))
210 			goto out_dir;
211 
212 		err = -ENOENT;
213 		new_de = minix_find_entry(new_dentry, &new_page);
214 		if (!new_de)
215 			goto out_dir;
216 		minix_set_link(new_de, new_page, old_inode);
217 		new_inode->i_ctime = CURRENT_TIME_SEC;
218 		if (dir_de)
219 			drop_nlink(new_inode);
220 		inode_dec_link_count(new_inode);
221 	} else {
222 		if (dir_de) {
223 			err = -EMLINK;
224 			if (new_dir->i_nlink >= info->s_link_max)
225 				goto out_dir;
226 		}
227 		err = minix_add_link(new_dentry, old_inode);
228 		if (err)
229 			goto out_dir;
230 		if (dir_de)
231 			inode_inc_link_count(new_dir);
232 	}
233 
234 	minix_delete_entry(old_de, old_page);
235 	mark_inode_dirty(old_inode);
236 
237 	if (dir_de) {
238 		minix_set_link(dir_de, dir_page, new_dir);
239 		inode_dec_link_count(old_dir);
240 	}
241 	return 0;
242 
243 out_dir:
244 	if (dir_de) {
245 		kunmap(dir_page);
246 		page_cache_release(dir_page);
247 	}
248 out_old:
249 	kunmap(old_page);
250 	page_cache_release(old_page);
251 out:
252 	return err;
253 }
254 
255 /*
256  * directories can handle most operations...
257  */
258 const struct inode_operations minix_dir_inode_operations = {
259 	.create		= minix_create,
260 	.lookup		= minix_lookup,
261 	.link		= minix_link,
262 	.unlink		= minix_unlink,
263 	.symlink	= minix_symlink,
264 	.mkdir		= minix_mkdir,
265 	.rmdir		= minix_rmdir,
266 	.mknod		= minix_mknod,
267 	.rename		= minix_rename,
268 	.getattr	= minix_getattr,
269 };
270