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1/*
2 * linux/fs/sysv/namei.c
3 *
4 * minix/namei.c
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 *
7 * coh/namei.c
8 * Copyright (C) 1993 Pascal Haible, Bruno Haible
9 *
10 * sysv/namei.c
11 * Copyright (C) 1993 Bruno Haible
12 * Copyright (C) 1997, 1998 Krzysztof G. Baranowski
13 */
14
15#include <linux/pagemap.h>
16#include "sysv.h"
17
18static int add_nondir(struct dentry *dentry, struct inode *inode)
19{
20 int err = sysv_add_link(dentry, inode);
21 if (!err) {
22 d_instantiate(dentry, inode);
23 return 0;
24 }
25 inode_dec_link_count(inode);
26 iput(inode);
27 return err;
28}
29
30static int sysv_hash(const struct dentry *dentry, const struct inode *inode,
31 struct qstr *qstr)
32{
33 /* Truncate the name in place, avoids having to define a compare
34 function. */
35 if (qstr->len > SYSV_NAMELEN) {
36 qstr->len = SYSV_NAMELEN;
37 qstr->hash = full_name_hash(qstr->name, qstr->len);
38 }
39 return 0;
40}
41
42const struct dentry_operations sysv_dentry_operations = {
43 .d_hash = sysv_hash,
44};
45
46static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
47{
48 struct inode * inode = NULL;
49 ino_t ino;
50
51 if (dentry->d_name.len > SYSV_NAMELEN)
52 return ERR_PTR(-ENAMETOOLONG);
53 ino = sysv_inode_by_name(dentry);
54
55 if (ino) {
56 inode = sysv_iget(dir->i_sb, ino);
57 if (IS_ERR(inode))
58 return ERR_CAST(inode);
59 }
60 d_add(dentry, inode);
61 return NULL;
62}
63
64static int sysv_mknod(struct inode * dir, struct dentry * dentry, umode_t mode, dev_t rdev)
65{
66 struct inode * inode;
67 int err;
68
69 if (!old_valid_dev(rdev))
70 return -EINVAL;
71
72 inode = sysv_new_inode(dir, mode);
73 err = PTR_ERR(inode);
74
75 if (!IS_ERR(inode)) {
76 sysv_set_inode(inode, rdev);
77 mark_inode_dirty(inode);
78 err = add_nondir(dentry, inode);
79 }
80 return err;
81}
82
83static int sysv_create(struct inode * dir, struct dentry * dentry, umode_t mode, struct nameidata *nd)
84{
85 return sysv_mknod(dir, dentry, mode, 0);
86}
87
88static int sysv_symlink(struct inode * dir, struct dentry * dentry,
89 const char * symname)
90{
91 int err = -ENAMETOOLONG;
92 int l = strlen(symname)+1;
93 struct inode * inode;
94
95 if (l > dir->i_sb->s_blocksize)
96 goto out;
97
98 inode = sysv_new_inode(dir, S_IFLNK|0777);
99 err = PTR_ERR(inode);
100 if (IS_ERR(inode))
101 goto out;
102
103 sysv_set_inode(inode, 0);
104 err = page_symlink(inode, symname, l);
105 if (err)
106 goto out_fail;
107
108 mark_inode_dirty(inode);
109 err = add_nondir(dentry, inode);
110out:
111 return err;
112
113out_fail:
114 inode_dec_link_count(inode);
115 iput(inode);
116 goto out;
117}
118
119static int sysv_link(struct dentry * old_dentry, struct inode * dir,
120 struct dentry * dentry)
121{
122 struct inode *inode = old_dentry->d_inode;
123
124 inode->i_ctime = CURRENT_TIME_SEC;
125 inode_inc_link_count(inode);
126 ihold(inode);
127
128 return add_nondir(dentry, inode);
129}
130
131static int sysv_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode)
132{
133 struct inode * inode;
134 int err;
135
136 inode_inc_link_count(dir);
137
138 inode = sysv_new_inode(dir, S_IFDIR|mode);
139 err = PTR_ERR(inode);
140 if (IS_ERR(inode))
141 goto out_dir;
142
143 sysv_set_inode(inode, 0);
144
145 inode_inc_link_count(inode);
146
147 err = sysv_make_empty(inode, dir);
148 if (err)
149 goto out_fail;
150
151 err = sysv_add_link(dentry, inode);
152 if (err)
153 goto out_fail;
154
155 d_instantiate(dentry, inode);
156out:
157 return err;
158
159out_fail:
160 inode_dec_link_count(inode);
161 inode_dec_link_count(inode);
162 iput(inode);
163out_dir:
164 inode_dec_link_count(dir);
165 goto out;
166}
167
168static int sysv_unlink(struct inode * dir, struct dentry * dentry)
169{
170 struct inode * inode = dentry->d_inode;
171 struct page * page;
172 struct sysv_dir_entry * de;
173 int err = -ENOENT;
174
175 de = sysv_find_entry(dentry, &page);
176 if (!de)
177 goto out;
178
179 err = sysv_delete_entry (de, page);
180 if (err)
181 goto out;
182
183 inode->i_ctime = dir->i_ctime;
184 inode_dec_link_count(inode);
185out:
186 return err;
187}
188
189static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
190{
191 struct inode *inode = dentry->d_inode;
192 int err = -ENOTEMPTY;
193
194 if (sysv_empty_dir(inode)) {
195 err = sysv_unlink(dir, dentry);
196 if (!err) {
197 inode->i_size = 0;
198 inode_dec_link_count(inode);
199 inode_dec_link_count(dir);
200 }
201 }
202 return err;
203}
204
205/*
206 * Anybody can rename anything with this: the permission checks are left to the
207 * higher-level routines.
208 */
209static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
210 struct inode * new_dir, struct dentry * new_dentry)
211{
212 struct inode * old_inode = old_dentry->d_inode;
213 struct inode * new_inode = new_dentry->d_inode;
214 struct page * dir_page = NULL;
215 struct sysv_dir_entry * dir_de = NULL;
216 struct page * old_page;
217 struct sysv_dir_entry * old_de;
218 int err = -ENOENT;
219
220 old_de = sysv_find_entry(old_dentry, &old_page);
221 if (!old_de)
222 goto out;
223
224 if (S_ISDIR(old_inode->i_mode)) {
225 err = -EIO;
226 dir_de = sysv_dotdot(old_inode, &dir_page);
227 if (!dir_de)
228 goto out_old;
229 }
230
231 if (new_inode) {
232 struct page * new_page;
233 struct sysv_dir_entry * new_de;
234
235 err = -ENOTEMPTY;
236 if (dir_de && !sysv_empty_dir(new_inode))
237 goto out_dir;
238
239 err = -ENOENT;
240 new_de = sysv_find_entry(new_dentry, &new_page);
241 if (!new_de)
242 goto out_dir;
243 sysv_set_link(new_de, new_page, old_inode);
244 new_inode->i_ctime = CURRENT_TIME_SEC;
245 if (dir_de)
246 drop_nlink(new_inode);
247 inode_dec_link_count(new_inode);
248 } else {
249 err = sysv_add_link(new_dentry, old_inode);
250 if (err)
251 goto out_dir;
252 if (dir_de)
253 inode_inc_link_count(new_dir);
254 }
255
256 sysv_delete_entry(old_de, old_page);
257 mark_inode_dirty(old_inode);
258
259 if (dir_de) {
260 sysv_set_link(dir_de, dir_page, new_dir);
261 inode_dec_link_count(old_dir);
262 }
263 return 0;
264
265out_dir:
266 if (dir_de) {
267 kunmap(dir_page);
268 page_cache_release(dir_page);
269 }
270out_old:
271 kunmap(old_page);
272 page_cache_release(old_page);
273out:
274 return err;
275}
276
277/*
278 * directories can handle most operations...
279 */
280const struct inode_operations sysv_dir_inode_operations = {
281 .create = sysv_create,
282 .lookup = sysv_lookup,
283 .link = sysv_link,
284 .unlink = sysv_unlink,
285 .symlink = sysv_symlink,
286 .mkdir = sysv_mkdir,
287 .rmdir = sysv_rmdir,
288 .mknod = sysv_mknod,
289 .rename = sysv_rename,
290 .getattr = sysv_getattr,
291};