1 /*
2 * linux/fs/ext2/namei.c
3 *
4 * Rewrite to pagecache. Almost all code had been changed, so blame me
5 * if the things go wrong. Please, send bug reports to
6 * viro@parcelfarce.linux.theplanet.co.uk
7 *
8 * Stuff here is basically a glue between the VFS and generic UNIXish
9 * filesystem that keeps everything in pagecache. All knowledge of the
10 * directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
11 * and it's easier to debug that way. In principle we might want to
12 * generalize that a bit and turn it into a library. Or not.
13 *
14 * The only non-static object here is ext2_dir_inode_operations.
15 *
16 * TODO: get rid of kmap() use, add readahead.
17 *
18 * Copyright (C) 1992, 1993, 1994, 1995
19 * Remy Card (card@masi.ibp.fr)
20 * Laboratoire MASI - Institut Blaise Pascal
21 * Universite Pierre et Marie Curie (Paris VI)
22 *
23 * from
24 *
25 * linux/fs/minix/namei.c
26 *
27 * Copyright (C) 1991, 1992 Linus Torvalds
28 *
29 * Big-endian to little-endian byte-swapping/bitmaps by
30 * David S. Miller (davem@caip.rutgers.edu), 1995
31 */
32
33 #include <linux/pagemap.h>
34 #include "ext2.h"
35 #include "xattr.h"
36 #include "acl.h"
37 #include "xip.h"
38
ext2_add_nondir(struct dentry * dentry,struct inode * inode)39 static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
40 {
41 int err = ext2_add_link(dentry, inode);
42 if (!err) {
43 d_instantiate(dentry, inode);
44 unlock_new_inode(inode);
45 return 0;
46 }
47 inode_dec_link_count(inode);
48 unlock_new_inode(inode);
49 iput(inode);
50 return err;
51 }
52
53 /*
54 * Methods themselves.
55 */
56
ext2_lookup(struct inode * dir,struct dentry * dentry,struct nameidata * nd)57 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
58 {
59 struct inode * inode;
60 ino_t ino;
61
62 if (dentry->d_name.len > EXT2_NAME_LEN)
63 return ERR_PTR(-ENAMETOOLONG);
64
65 ino = ext2_inode_by_name(dir, &dentry->d_name);
66 inode = NULL;
67 if (ino) {
68 inode = ext2_iget(dir->i_sb, ino);
69 if (IS_ERR(inode))
70 return ERR_CAST(inode);
71 }
72 return d_splice_alias(inode, dentry);
73 }
74
ext2_get_parent(struct dentry * child)75 struct dentry *ext2_get_parent(struct dentry *child)
76 {
77 struct qstr dotdot = {.name = "..", .len = 2};
78 unsigned long ino = ext2_inode_by_name(child->d_inode, &dotdot);
79 if (!ino)
80 return ERR_PTR(-ENOENT);
81 return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino));
82 }
83
84 /*
85 * By the time this is called, we already have created
86 * the directory cache entry for the new file, but it
87 * is so far negative - it has no inode.
88 *
89 * If the create succeeds, we fill in the inode information
90 * with d_instantiate().
91 */
ext2_create(struct inode * dir,struct dentry * dentry,int mode,struct nameidata * nd)92 static int ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd)
93 {
94 struct inode * inode = ext2_new_inode (dir, mode);
95 int err = PTR_ERR(inode);
96 if (!IS_ERR(inode)) {
97 inode->i_op = &ext2_file_inode_operations;
98 if (ext2_use_xip(inode->i_sb)) {
99 inode->i_mapping->a_ops = &ext2_aops_xip;
100 inode->i_fop = &ext2_xip_file_operations;
101 } else if (test_opt(inode->i_sb, NOBH)) {
102 inode->i_mapping->a_ops = &ext2_nobh_aops;
103 inode->i_fop = &ext2_file_operations;
104 } else {
105 inode->i_mapping->a_ops = &ext2_aops;
106 inode->i_fop = &ext2_file_operations;
107 }
108 mark_inode_dirty(inode);
109 err = ext2_add_nondir(dentry, inode);
110 }
111 return err;
112 }
113
ext2_mknod(struct inode * dir,struct dentry * dentry,int mode,dev_t rdev)114 static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
115 {
116 struct inode * inode;
117 int err;
118
119 if (!new_valid_dev(rdev))
120 return -EINVAL;
121
122 inode = ext2_new_inode (dir, mode);
123 err = PTR_ERR(inode);
124 if (!IS_ERR(inode)) {
125 init_special_inode(inode, inode->i_mode, rdev);
126 #ifdef CONFIG_EXT2_FS_XATTR
127 inode->i_op = &ext2_special_inode_operations;
128 #endif
129 mark_inode_dirty(inode);
130 err = ext2_add_nondir(dentry, inode);
131 }
132 return err;
133 }
134
ext2_symlink(struct inode * dir,struct dentry * dentry,const char * symname)135 static int ext2_symlink (struct inode * dir, struct dentry * dentry,
136 const char * symname)
137 {
138 struct super_block * sb = dir->i_sb;
139 int err = -ENAMETOOLONG;
140 unsigned l = strlen(symname)+1;
141 struct inode * inode;
142
143 if (l > sb->s_blocksize)
144 goto out;
145
146 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO);
147 err = PTR_ERR(inode);
148 if (IS_ERR(inode))
149 goto out;
150
151 if (l > sizeof (EXT2_I(inode)->i_data)) {
152 /* slow symlink */
153 inode->i_op = &ext2_symlink_inode_operations;
154 if (test_opt(inode->i_sb, NOBH))
155 inode->i_mapping->a_ops = &ext2_nobh_aops;
156 else
157 inode->i_mapping->a_ops = &ext2_aops;
158 err = page_symlink(inode, symname, l);
159 if (err)
160 goto out_fail;
161 } else {
162 /* fast symlink */
163 inode->i_op = &ext2_fast_symlink_inode_operations;
164 memcpy((char*)(EXT2_I(inode)->i_data),symname,l);
165 inode->i_size = l-1;
166 }
167 mark_inode_dirty(inode);
168
169 err = ext2_add_nondir(dentry, inode);
170 out:
171 return err;
172
173 out_fail:
174 inode_dec_link_count(inode);
175 unlock_new_inode(inode);
176 iput (inode);
177 goto out;
178 }
179
ext2_link(struct dentry * old_dentry,struct inode * dir,struct dentry * dentry)180 static int ext2_link (struct dentry * old_dentry, struct inode * dir,
181 struct dentry *dentry)
182 {
183 struct inode *inode = old_dentry->d_inode;
184 int err;
185
186 if (inode->i_nlink >= EXT2_LINK_MAX)
187 return -EMLINK;
188
189 inode->i_ctime = CURRENT_TIME_SEC;
190 inode_inc_link_count(inode);
191 atomic_inc(&inode->i_count);
192
193 err = ext2_add_link(dentry, inode);
194 if (!err) {
195 d_instantiate(dentry, inode);
196 return 0;
197 }
198 inode_dec_link_count(inode);
199 iput(inode);
200 return err;
201 }
202
ext2_mkdir(struct inode * dir,struct dentry * dentry,int mode)203 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode)
204 {
205 struct inode * inode;
206 int err = -EMLINK;
207
208 if (dir->i_nlink >= EXT2_LINK_MAX)
209 goto out;
210
211 inode_inc_link_count(dir);
212
213 inode = ext2_new_inode (dir, S_IFDIR | mode);
214 err = PTR_ERR(inode);
215 if (IS_ERR(inode))
216 goto out_dir;
217
218 inode->i_op = &ext2_dir_inode_operations;
219 inode->i_fop = &ext2_dir_operations;
220 if (test_opt(inode->i_sb, NOBH))
221 inode->i_mapping->a_ops = &ext2_nobh_aops;
222 else
223 inode->i_mapping->a_ops = &ext2_aops;
224
225 inode_inc_link_count(inode);
226
227 err = ext2_make_empty(inode, dir);
228 if (err)
229 goto out_fail;
230
231 err = ext2_add_link(dentry, inode);
232 if (err)
233 goto out_fail;
234
235 d_instantiate(dentry, inode);
236 unlock_new_inode(inode);
237 out:
238 return err;
239
240 out_fail:
241 inode_dec_link_count(inode);
242 inode_dec_link_count(inode);
243 unlock_new_inode(inode);
244 iput(inode);
245 out_dir:
246 inode_dec_link_count(dir);
247 goto out;
248 }
249
ext2_unlink(struct inode * dir,struct dentry * dentry)250 static int ext2_unlink(struct inode * dir, struct dentry *dentry)
251 {
252 struct inode * inode = dentry->d_inode;
253 struct ext2_dir_entry_2 * de;
254 struct page * page;
255 int err = -ENOENT;
256
257 de = ext2_find_entry (dir, &dentry->d_name, &page);
258 if (!de)
259 goto out;
260
261 err = ext2_delete_entry (de, page);
262 if (err)
263 goto out;
264
265 inode->i_ctime = dir->i_ctime;
266 inode_dec_link_count(inode);
267 err = 0;
268 out:
269 return err;
270 }
271
ext2_rmdir(struct inode * dir,struct dentry * dentry)272 static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
273 {
274 struct inode * inode = dentry->d_inode;
275 int err = -ENOTEMPTY;
276
277 if (ext2_empty_dir(inode)) {
278 err = ext2_unlink(dir, dentry);
279 if (!err) {
280 inode->i_size = 0;
281 inode_dec_link_count(inode);
282 inode_dec_link_count(dir);
283 }
284 }
285 return err;
286 }
287
ext2_rename(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry)288 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
289 struct inode * new_dir, struct dentry * new_dentry )
290 {
291 struct inode * old_inode = old_dentry->d_inode;
292 struct inode * new_inode = new_dentry->d_inode;
293 struct page * dir_page = NULL;
294 struct ext2_dir_entry_2 * dir_de = NULL;
295 struct page * old_page;
296 struct ext2_dir_entry_2 * old_de;
297 int err = -ENOENT;
298
299 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page);
300 if (!old_de)
301 goto out;
302
303 if (S_ISDIR(old_inode->i_mode)) {
304 err = -EIO;
305 dir_de = ext2_dotdot(old_inode, &dir_page);
306 if (!dir_de)
307 goto out_old;
308 }
309
310 if (new_inode) {
311 struct page *new_page;
312 struct ext2_dir_entry_2 *new_de;
313
314 err = -ENOTEMPTY;
315 if (dir_de && !ext2_empty_dir (new_inode))
316 goto out_dir;
317
318 err = -ENOENT;
319 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page);
320 if (!new_de)
321 goto out_dir;
322 inode_inc_link_count(old_inode);
323 ext2_set_link(new_dir, new_de, new_page, old_inode);
324 new_inode->i_ctime = CURRENT_TIME_SEC;
325 if (dir_de)
326 drop_nlink(new_inode);
327 inode_dec_link_count(new_inode);
328 } else {
329 if (dir_de) {
330 err = -EMLINK;
331 if (new_dir->i_nlink >= EXT2_LINK_MAX)
332 goto out_dir;
333 }
334 inode_inc_link_count(old_inode);
335 err = ext2_add_link(new_dentry, old_inode);
336 if (err) {
337 inode_dec_link_count(old_inode);
338 goto out_dir;
339 }
340 if (dir_de)
341 inode_inc_link_count(new_dir);
342 }
343
344 /*
345 * Like most other Unix systems, set the ctime for inodes on a
346 * rename.
347 * inode_dec_link_count() will mark the inode dirty.
348 */
349 old_inode->i_ctime = CURRENT_TIME_SEC;
350
351 ext2_delete_entry (old_de, old_page);
352 inode_dec_link_count(old_inode);
353
354 if (dir_de) {
355 ext2_set_link(old_inode, dir_de, dir_page, new_dir);
356 inode_dec_link_count(old_dir);
357 }
358 return 0;
359
360
361 out_dir:
362 if (dir_de) {
363 kunmap(dir_page);
364 page_cache_release(dir_page);
365 }
366 out_old:
367 kunmap(old_page);
368 page_cache_release(old_page);
369 out:
370 return err;
371 }
372
373 const struct inode_operations ext2_dir_inode_operations = {
374 .create = ext2_create,
375 .lookup = ext2_lookup,
376 .link = ext2_link,
377 .unlink = ext2_unlink,
378 .symlink = ext2_symlink,
379 .mkdir = ext2_mkdir,
380 .rmdir = ext2_rmdir,
381 .mknod = ext2_mknod,
382 .rename = ext2_rename,
383 #ifdef CONFIG_EXT2_FS_XATTR
384 .setxattr = generic_setxattr,
385 .getxattr = generic_getxattr,
386 .listxattr = ext2_listxattr,
387 .removexattr = generic_removexattr,
388 #endif
389 .setattr = ext2_setattr,
390 .permission = ext2_permission,
391 };
392
393 const struct inode_operations ext2_special_inode_operations = {
394 #ifdef CONFIG_EXT2_FS_XATTR
395 .setxattr = generic_setxattr,
396 .getxattr = generic_getxattr,
397 .listxattr = ext2_listxattr,
398 .removexattr = generic_removexattr,
399 #endif
400 .setattr = ext2_setattr,
401 .permission = ext2_permission,
402 };
403