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 <linux/quotaops.h>
35 #include "ext2.h"
36 #include "xattr.h"
37 #include "acl.h"
38 #include "xip.h"
39
ext2_add_nondir(struct dentry * dentry,struct inode * inode)40 static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
41 {
42 int err = ext2_add_link(dentry, inode);
43 if (!err) {
44 unlock_new_inode(inode);
45 d_instantiate(dentry, inode);
46 return 0;
47 }
48 inode_dec_link_count(inode);
49 unlock_new_inode(inode);
50 iput(inode);
51 return err;
52 }
53
54 /*
55 * Methods themselves.
56 */
57
ext2_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)58 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
59 {
60 struct inode * inode;
61 ino_t ino;
62
63 if (dentry->d_name.len > EXT2_NAME_LEN)
64 return ERR_PTR(-ENAMETOOLONG);
65
66 ino = ext2_inode_by_name(dir, &dentry->d_name);
67 inode = NULL;
68 if (ino) {
69 inode = ext2_iget(dir->i_sb, ino);
70 if (inode == ERR_PTR(-ESTALE)) {
71 ext2_error(dir->i_sb, __func__,
72 "deleted inode referenced: %lu",
73 (unsigned long) ino);
74 return ERR_PTR(-EIO);
75 }
76 }
77 return d_splice_alias(inode, dentry);
78 }
79
ext2_get_parent(struct dentry * child)80 struct dentry *ext2_get_parent(struct dentry *child)
81 {
82 struct qstr dotdot = QSTR_INIT("..", 2);
83 unsigned long ino = ext2_inode_by_name(child->d_inode, &dotdot);
84 if (!ino)
85 return ERR_PTR(-ENOENT);
86 return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino));
87 }
88
89 /*
90 * By the time this is called, we already have created
91 * the directory cache entry for the new file, but it
92 * is so far negative - it has no inode.
93 *
94 * If the create succeeds, we fill in the inode information
95 * with d_instantiate().
96 */
ext2_create(struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)97 static int ext2_create (struct inode * dir, struct dentry * dentry, umode_t mode, bool excl)
98 {
99 struct inode *inode;
100
101 dquot_initialize(dir);
102
103 inode = ext2_new_inode(dir, mode, &dentry->d_name);
104 if (IS_ERR(inode))
105 return PTR_ERR(inode);
106
107 inode->i_op = &ext2_file_inode_operations;
108 if (ext2_use_xip(inode->i_sb)) {
109 inode->i_mapping->a_ops = &ext2_aops_xip;
110 inode->i_fop = &ext2_xip_file_operations;
111 } else if (test_opt(inode->i_sb, NOBH)) {
112 inode->i_mapping->a_ops = &ext2_nobh_aops;
113 inode->i_fop = &ext2_file_operations;
114 } else {
115 inode->i_mapping->a_ops = &ext2_aops;
116 inode->i_fop = &ext2_file_operations;
117 }
118 mark_inode_dirty(inode);
119 return ext2_add_nondir(dentry, inode);
120 }
121
ext2_tmpfile(struct inode * dir,struct dentry * dentry,umode_t mode)122 static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
123 {
124 struct inode *inode = ext2_new_inode(dir, mode, NULL);
125 if (IS_ERR(inode))
126 return PTR_ERR(inode);
127
128 inode->i_op = &ext2_file_inode_operations;
129 if (ext2_use_xip(inode->i_sb)) {
130 inode->i_mapping->a_ops = &ext2_aops_xip;
131 inode->i_fop = &ext2_xip_file_operations;
132 } else if (test_opt(inode->i_sb, NOBH)) {
133 inode->i_mapping->a_ops = &ext2_nobh_aops;
134 inode->i_fop = &ext2_file_operations;
135 } else {
136 inode->i_mapping->a_ops = &ext2_aops;
137 inode->i_fop = &ext2_file_operations;
138 }
139 mark_inode_dirty(inode);
140 d_tmpfile(dentry, inode);
141 unlock_new_inode(inode);
142 return 0;
143 }
144
ext2_mknod(struct inode * dir,struct dentry * dentry,umode_t mode,dev_t rdev)145 static int ext2_mknod (struct inode * dir, struct dentry *dentry, umode_t mode, dev_t rdev)
146 {
147 struct inode * inode;
148 int err;
149
150 if (!new_valid_dev(rdev))
151 return -EINVAL;
152
153 dquot_initialize(dir);
154
155 inode = ext2_new_inode (dir, mode, &dentry->d_name);
156 err = PTR_ERR(inode);
157 if (!IS_ERR(inode)) {
158 init_special_inode(inode, inode->i_mode, rdev);
159 #ifdef CONFIG_EXT2_FS_XATTR
160 inode->i_op = &ext2_special_inode_operations;
161 #endif
162 mark_inode_dirty(inode);
163 err = ext2_add_nondir(dentry, inode);
164 }
165 return err;
166 }
167
ext2_symlink(struct inode * dir,struct dentry * dentry,const char * symname)168 static int ext2_symlink (struct inode * dir, struct dentry * dentry,
169 const char * symname)
170 {
171 struct super_block * sb = dir->i_sb;
172 int err = -ENAMETOOLONG;
173 unsigned l = strlen(symname)+1;
174 struct inode * inode;
175
176 if (l > sb->s_blocksize)
177 goto out;
178
179 dquot_initialize(dir);
180
181 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name);
182 err = PTR_ERR(inode);
183 if (IS_ERR(inode))
184 goto out;
185
186 if (l > sizeof (EXT2_I(inode)->i_data)) {
187 /* slow symlink */
188 inode->i_op = &ext2_symlink_inode_operations;
189 if (test_opt(inode->i_sb, NOBH))
190 inode->i_mapping->a_ops = &ext2_nobh_aops;
191 else
192 inode->i_mapping->a_ops = &ext2_aops;
193 err = page_symlink(inode, symname, l);
194 if (err)
195 goto out_fail;
196 } else {
197 /* fast symlink */
198 inode->i_op = &ext2_fast_symlink_inode_operations;
199 memcpy((char*)(EXT2_I(inode)->i_data),symname,l);
200 inode->i_size = l-1;
201 }
202 mark_inode_dirty(inode);
203
204 err = ext2_add_nondir(dentry, inode);
205 out:
206 return err;
207
208 out_fail:
209 inode_dec_link_count(inode);
210 unlock_new_inode(inode);
211 iput (inode);
212 goto out;
213 }
214
ext2_link(struct dentry * old_dentry,struct inode * dir,struct dentry * dentry)215 static int ext2_link (struct dentry * old_dentry, struct inode * dir,
216 struct dentry *dentry)
217 {
218 struct inode *inode = old_dentry->d_inode;
219 int err;
220
221 dquot_initialize(dir);
222
223 inode->i_ctime = CURRENT_TIME_SEC;
224 inode_inc_link_count(inode);
225 ihold(inode);
226
227 err = ext2_add_link(dentry, inode);
228 if (!err) {
229 d_instantiate(dentry, inode);
230 return 0;
231 }
232 inode_dec_link_count(inode);
233 iput(inode);
234 return err;
235 }
236
ext2_mkdir(struct inode * dir,struct dentry * dentry,umode_t mode)237 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
238 {
239 struct inode * inode;
240 int err;
241
242 dquot_initialize(dir);
243
244 inode_inc_link_count(dir);
245
246 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name);
247 err = PTR_ERR(inode);
248 if (IS_ERR(inode))
249 goto out_dir;
250
251 inode->i_op = &ext2_dir_inode_operations;
252 inode->i_fop = &ext2_dir_operations;
253 if (test_opt(inode->i_sb, NOBH))
254 inode->i_mapping->a_ops = &ext2_nobh_aops;
255 else
256 inode->i_mapping->a_ops = &ext2_aops;
257
258 inode_inc_link_count(inode);
259
260 err = ext2_make_empty(inode, dir);
261 if (err)
262 goto out_fail;
263
264 err = ext2_add_link(dentry, inode);
265 if (err)
266 goto out_fail;
267
268 unlock_new_inode(inode);
269 d_instantiate(dentry, inode);
270 out:
271 return err;
272
273 out_fail:
274 inode_dec_link_count(inode);
275 inode_dec_link_count(inode);
276 unlock_new_inode(inode);
277 iput(inode);
278 out_dir:
279 inode_dec_link_count(dir);
280 goto out;
281 }
282
ext2_unlink(struct inode * dir,struct dentry * dentry)283 static int ext2_unlink(struct inode * dir, struct dentry *dentry)
284 {
285 struct inode * inode = dentry->d_inode;
286 struct ext2_dir_entry_2 * de;
287 struct page * page;
288 int err = -ENOENT;
289
290 dquot_initialize(dir);
291
292 de = ext2_find_entry (dir, &dentry->d_name, &page);
293 if (!de)
294 goto out;
295
296 err = ext2_delete_entry (de, page);
297 if (err)
298 goto out;
299
300 inode->i_ctime = dir->i_ctime;
301 inode_dec_link_count(inode);
302 err = 0;
303 out:
304 return err;
305 }
306
ext2_rmdir(struct inode * dir,struct dentry * dentry)307 static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
308 {
309 struct inode * inode = dentry->d_inode;
310 int err = -ENOTEMPTY;
311
312 if (ext2_empty_dir(inode)) {
313 err = ext2_unlink(dir, dentry);
314 if (!err) {
315 inode->i_size = 0;
316 inode_dec_link_count(inode);
317 inode_dec_link_count(dir);
318 }
319 }
320 return err;
321 }
322
ext2_rename(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry)323 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
324 struct inode * new_dir, struct dentry * new_dentry )
325 {
326 struct inode * old_inode = old_dentry->d_inode;
327 struct inode * new_inode = new_dentry->d_inode;
328 struct page * dir_page = NULL;
329 struct ext2_dir_entry_2 * dir_de = NULL;
330 struct page * old_page;
331 struct ext2_dir_entry_2 * old_de;
332 int err = -ENOENT;
333
334 dquot_initialize(old_dir);
335 dquot_initialize(new_dir);
336
337 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page);
338 if (!old_de)
339 goto out;
340
341 if (S_ISDIR(old_inode->i_mode)) {
342 err = -EIO;
343 dir_de = ext2_dotdot(old_inode, &dir_page);
344 if (!dir_de)
345 goto out_old;
346 }
347
348 if (new_inode) {
349 struct page *new_page;
350 struct ext2_dir_entry_2 *new_de;
351
352 err = -ENOTEMPTY;
353 if (dir_de && !ext2_empty_dir (new_inode))
354 goto out_dir;
355
356 err = -ENOENT;
357 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page);
358 if (!new_de)
359 goto out_dir;
360 ext2_set_link(new_dir, new_de, new_page, old_inode, 1);
361 new_inode->i_ctime = CURRENT_TIME_SEC;
362 if (dir_de)
363 drop_nlink(new_inode);
364 inode_dec_link_count(new_inode);
365 } else {
366 err = ext2_add_link(new_dentry, old_inode);
367 if (err)
368 goto out_dir;
369 if (dir_de)
370 inode_inc_link_count(new_dir);
371 }
372
373 /*
374 * Like most other Unix systems, set the ctime for inodes on a
375 * rename.
376 */
377 old_inode->i_ctime = CURRENT_TIME_SEC;
378 mark_inode_dirty(old_inode);
379
380 ext2_delete_entry (old_de, old_page);
381
382 if (dir_de) {
383 if (old_dir != new_dir)
384 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0);
385 else {
386 kunmap(dir_page);
387 page_cache_release(dir_page);
388 }
389 inode_dec_link_count(old_dir);
390 }
391 return 0;
392
393
394 out_dir:
395 if (dir_de) {
396 kunmap(dir_page);
397 page_cache_release(dir_page);
398 }
399 out_old:
400 kunmap(old_page);
401 page_cache_release(old_page);
402 out:
403 return err;
404 }
405
406 const struct inode_operations ext2_dir_inode_operations = {
407 .create = ext2_create,
408 .lookup = ext2_lookup,
409 .link = ext2_link,
410 .unlink = ext2_unlink,
411 .symlink = ext2_symlink,
412 .mkdir = ext2_mkdir,
413 .rmdir = ext2_rmdir,
414 .mknod = ext2_mknod,
415 .rename = ext2_rename,
416 #ifdef CONFIG_EXT2_FS_XATTR
417 .setxattr = generic_setxattr,
418 .getxattr = generic_getxattr,
419 .listxattr = ext2_listxattr,
420 .removexattr = generic_removexattr,
421 #endif
422 .setattr = ext2_setattr,
423 .get_acl = ext2_get_acl,
424 .set_acl = ext2_set_acl,
425 .tmpfile = ext2_tmpfile,
426 };
427
428 const struct inode_operations ext2_special_inode_operations = {
429 #ifdef CONFIG_EXT2_FS_XATTR
430 .setxattr = generic_setxattr,
431 .getxattr = generic_getxattr,
432 .listxattr = ext2_listxattr,
433 .removexattr = generic_removexattr,
434 #endif
435 .setattr = ext2_setattr,
436 .get_acl = ext2_get_acl,
437 .set_acl = ext2_set_acl,
438 };
439