1 /*
2 * namei.c - NILFS pathname lookup operations.
3 *
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 *
20 * Modified for NILFS by Amagai Yoshiji <amagai@osrg.net>,
21 * Ryusuke Konishi <ryusuke@osrg.net>
22 */
23 /*
24 * linux/fs/ext2/namei.c
25 *
26 * Copyright (C) 1992, 1993, 1994, 1995
27 * Remy Card (card@masi.ibp.fr)
28 * Laboratoire MASI - Institut Blaise Pascal
29 * Universite Pierre et Marie Curie (Paris VI)
30 *
31 * from
32 *
33 * linux/fs/minix/namei.c
34 *
35 * Copyright (C) 1991, 1992 Linus Torvalds
36 *
37 * Big-endian to little-endian byte-swapping/bitmaps by
38 * David S. Miller (davem@caip.rutgers.edu), 1995
39 */
40
41 #include <linux/pagemap.h>
42 #include "nilfs.h"
43
44
45 static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
46 {
47 int err = nilfs_add_link(dentry, inode);
48 if (!err) {
49 d_instantiate(dentry, inode);
50 return 0;
51 }
52 inode_dec_link_count(inode);
53 iput(inode);
54 return err;
55 }
56
57 /*
58 * Methods themselves.
59 */
60
61 static struct dentry *
62 nilfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
63 {
64 struct inode *inode;
65 ino_t ino;
66
67 if (dentry->d_name.len > NILFS_NAME_LEN)
68 return ERR_PTR(-ENAMETOOLONG);
69
70 ino = nilfs_inode_by_name(dir, dentry);
71 inode = NULL;
72 if (ino) {
73 inode = nilfs_iget(dir->i_sb, ino);
74 if (IS_ERR(inode))
75 return ERR_CAST(inode);
76 }
77 return d_splice_alias(inode, dentry);
78 }
79
80 struct dentry *nilfs_get_parent(struct dentry *child)
81 {
82 unsigned long ino;
83 struct inode *inode;
84 struct dentry dotdot;
85
86 dotdot.d_name.name = "..";
87 dotdot.d_name.len = 2;
88
89 ino = nilfs_inode_by_name(child->d_inode, &dotdot);
90 if (!ino)
91 return ERR_PTR(-ENOENT);
92
93 inode = nilfs_iget(child->d_inode->i_sb, ino);
94 if (IS_ERR(inode))
95 return ERR_CAST(inode);
96 return d_obtain_alias(inode);
97 }
98
99 /*
100 * By the time this is called, we already have created
101 * the directory cache entry for the new file, but it
102 * is so far negative - it has no inode.
103 *
104 * If the create succeeds, we fill in the inode information
105 * with d_instantiate().
106 */
107 static int nilfs_create(struct inode *dir, struct dentry *dentry, int mode,
108 struct nameidata *nd)
109 {
110 struct inode *inode;
111 struct nilfs_transaction_info ti;
112 int err;
113
114 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
115 if (err)
116 return err;
117 inode = nilfs_new_inode(dir, mode);
118 err = PTR_ERR(inode);
119 if (!IS_ERR(inode)) {
120 inode->i_op = &nilfs_file_inode_operations;
121 inode->i_fop = &nilfs_file_operations;
122 inode->i_mapping->a_ops = &nilfs_aops;
123 mark_inode_dirty(inode);
124 err = nilfs_add_nondir(dentry, inode);
125 }
126 if (!err)
127 err = nilfs_transaction_commit(dir->i_sb);
128 else
129 nilfs_transaction_abort(dir->i_sb);
130
131 return err;
132 }
133
134 static int
135 nilfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
136 {
137 struct inode *inode;
138 struct nilfs_transaction_info ti;
139 int err;
140
141 if (!new_valid_dev(rdev))
142 return -EINVAL;
143
144 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
145 if (err)
146 return err;
147 inode = nilfs_new_inode(dir, mode);
148 err = PTR_ERR(inode);
149 if (!IS_ERR(inode)) {
150 init_special_inode(inode, inode->i_mode, rdev);
151 mark_inode_dirty(inode);
152 err = nilfs_add_nondir(dentry, inode);
153 }
154 if (!err)
155 err = nilfs_transaction_commit(dir->i_sb);
156 else
157 nilfs_transaction_abort(dir->i_sb);
158
159 return err;
160 }
161
162 static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
163 const char *symname)
164 {
165 struct nilfs_transaction_info ti;
166 struct super_block *sb = dir->i_sb;
167 unsigned l = strlen(symname)+1;
168 struct inode *inode;
169 int err;
170
171 if (l > sb->s_blocksize)
172 return -ENAMETOOLONG;
173
174 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
175 if (err)
176 return err;
177
178 inode = nilfs_new_inode(dir, S_IFLNK | S_IRWXUGO);
179 err = PTR_ERR(inode);
180 if (IS_ERR(inode))
181 goto out;
182
183 /* slow symlink */
184 inode->i_op = &nilfs_symlink_inode_operations;
185 inode->i_mapping->a_ops = &nilfs_aops;
186 err = page_symlink(inode, symname, l);
187 if (err)
188 goto out_fail;
189
190 /* mark_inode_dirty(inode); */
191 /* nilfs_new_inode() and page_symlink() do this */
192
193 err = nilfs_add_nondir(dentry, inode);
194 out:
195 if (!err)
196 err = nilfs_transaction_commit(dir->i_sb);
197 else
198 nilfs_transaction_abort(dir->i_sb);
199
200 return err;
201
202 out_fail:
203 inode_dec_link_count(inode);
204 iput(inode);
205 goto out;
206 }
207
208 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
209 struct dentry *dentry)
210 {
211 struct inode *inode = old_dentry->d_inode;
212 struct nilfs_transaction_info ti;
213 int err;
214
215 if (inode->i_nlink >= NILFS_LINK_MAX)
216 return -EMLINK;
217
218 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
219 if (err)
220 return err;
221
222 inode->i_ctime = CURRENT_TIME;
223 inode_inc_link_count(inode);
224 atomic_inc(&inode->i_count);
225
226 err = nilfs_add_nondir(dentry, inode);
227 if (!err)
228 err = nilfs_transaction_commit(dir->i_sb);
229 else
230 nilfs_transaction_abort(dir->i_sb);
231
232 return err;
233 }
234
235 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
236 {
237 struct inode *inode;
238 struct nilfs_transaction_info ti;
239 int err;
240
241 if (dir->i_nlink >= NILFS_LINK_MAX)
242 return -EMLINK;
243
244 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
245 if (err)
246 return err;
247
248 inode_inc_link_count(dir);
249
250 inode = nilfs_new_inode(dir, S_IFDIR | mode);
251 err = PTR_ERR(inode);
252 if (IS_ERR(inode))
253 goto out_dir;
254
255 inode->i_op = &nilfs_dir_inode_operations;
256 inode->i_fop = &nilfs_dir_operations;
257 inode->i_mapping->a_ops = &nilfs_aops;
258
259 inode_inc_link_count(inode);
260
261 err = nilfs_make_empty(inode, dir);
262 if (err)
263 goto out_fail;
264
265 err = nilfs_add_link(dentry, inode);
266 if (err)
267 goto out_fail;
268
269 d_instantiate(dentry, inode);
270 out:
271 if (!err)
272 err = nilfs_transaction_commit(dir->i_sb);
273 else
274 nilfs_transaction_abort(dir->i_sb);
275
276 return err;
277
278 out_fail:
279 inode_dec_link_count(inode);
280 inode_dec_link_count(inode);
281 iput(inode);
282 out_dir:
283 inode_dec_link_count(dir);
284 goto out;
285 }
286
287 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
288 {
289 struct inode *inode;
290 struct nilfs_dir_entry *de;
291 struct page *page;
292 struct nilfs_transaction_info ti;
293 int err;
294
295 err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
296 if (err)
297 return err;
298
299 err = -ENOENT;
300 de = nilfs_find_entry(dir, dentry, &page);
301 if (!de)
302 goto out;
303
304 inode = dentry->d_inode;
305 err = -EIO;
306 if (le64_to_cpu(de->inode) != inode->i_ino)
307 goto out;
308
309 if (!inode->i_nlink) {
310 nilfs_warning(inode->i_sb, __func__,
311 "deleting nonexistent file (%lu), %d\n",
312 inode->i_ino, inode->i_nlink);
313 inode->i_nlink = 1;
314 }
315 err = nilfs_delete_entry(de, page);
316 if (err)
317 goto out;
318
319 inode->i_ctime = dir->i_ctime;
320 inode_dec_link_count(inode);
321 err = 0;
322 out:
323 if (!err)
324 err = nilfs_transaction_commit(dir->i_sb);
325 else
326 nilfs_transaction_abort(dir->i_sb);
327
328 return err;
329 }
330
331 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
332 {
333 struct inode *inode = dentry->d_inode;
334 struct nilfs_transaction_info ti;
335 int err;
336
337 err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
338 if (err)
339 return err;
340
341 err = -ENOTEMPTY;
342 if (nilfs_empty_dir(inode)) {
343 err = nilfs_unlink(dir, dentry);
344 if (!err) {
345 inode->i_size = 0;
346 inode_dec_link_count(inode);
347 inode_dec_link_count(dir);
348 }
349 }
350 if (!err)
351 err = nilfs_transaction_commit(dir->i_sb);
352 else
353 nilfs_transaction_abort(dir->i_sb);
354
355 return err;
356 }
357
358 static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
359 struct inode *new_dir, struct dentry *new_dentry)
360 {
361 struct inode *old_inode = old_dentry->d_inode;
362 struct inode *new_inode = new_dentry->d_inode;
363 struct page *dir_page = NULL;
364 struct nilfs_dir_entry *dir_de = NULL;
365 struct page *old_page;
366 struct nilfs_dir_entry *old_de;
367 struct nilfs_transaction_info ti;
368 int err;
369
370 err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
371 if (unlikely(err))
372 return err;
373
374 err = -ENOENT;
375 old_de = nilfs_find_entry(old_dir, old_dentry, &old_page);
376 if (!old_de)
377 goto out;
378
379 if (S_ISDIR(old_inode->i_mode)) {
380 err = -EIO;
381 dir_de = nilfs_dotdot(old_inode, &dir_page);
382 if (!dir_de)
383 goto out_old;
384 }
385
386 if (new_inode) {
387 struct page *new_page;
388 struct nilfs_dir_entry *new_de;
389
390 err = -ENOTEMPTY;
391 if (dir_de && !nilfs_empty_dir(new_inode))
392 goto out_dir;
393
394 err = -ENOENT;
395 new_de = nilfs_find_entry(new_dir, new_dentry, &new_page);
396 if (!new_de)
397 goto out_dir;
398 inode_inc_link_count(old_inode);
399 nilfs_set_link(new_dir, new_de, new_page, old_inode);
400 new_inode->i_ctime = CURRENT_TIME;
401 if (dir_de)
402 drop_nlink(new_inode);
403 inode_dec_link_count(new_inode);
404 } else {
405 if (dir_de) {
406 err = -EMLINK;
407 if (new_dir->i_nlink >= NILFS_LINK_MAX)
408 goto out_dir;
409 }
410 inode_inc_link_count(old_inode);
411 err = nilfs_add_link(new_dentry, old_inode);
412 if (err) {
413 inode_dec_link_count(old_inode);
414 goto out_dir;
415 }
416 if (dir_de)
417 inode_inc_link_count(new_dir);
418 }
419
420 /*
421 * Like most other Unix systems, set the ctime for inodes on a
422 * rename.
423 * inode_dec_link_count() will mark the inode dirty.
424 */
425 old_inode->i_ctime = CURRENT_TIME;
426
427 nilfs_delete_entry(old_de, old_page);
428 inode_dec_link_count(old_inode);
429
430 if (dir_de) {
431 nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
432 inode_dec_link_count(old_dir);
433 }
434
435 err = nilfs_transaction_commit(old_dir->i_sb);
436 return err;
437
438 out_dir:
439 if (dir_de) {
440 kunmap(dir_page);
441 page_cache_release(dir_page);
442 }
443 out_old:
444 kunmap(old_page);
445 page_cache_release(old_page);
446 out:
447 nilfs_transaction_abort(old_dir->i_sb);
448 return err;
449 }
450
451 struct inode_operations nilfs_dir_inode_operations = {
452 .create = nilfs_create,
453 .lookup = nilfs_lookup,
454 .link = nilfs_link,
455 .unlink = nilfs_unlink,
456 .symlink = nilfs_symlink,
457 .mkdir = nilfs_mkdir,
458 .rmdir = nilfs_rmdir,
459 .mknod = nilfs_mknod,
460 .rename = nilfs_rename,
461 .setattr = nilfs_setattr,
462 .permission = nilfs_permission,
463 };
464
465 struct inode_operations nilfs_special_inode_operations = {
466 .setattr = nilfs_setattr,
467 .permission = nilfs_permission,
468 };
469
470 struct inode_operations nilfs_symlink_inode_operations = {
471 .readlink = generic_readlink,
472 .follow_link = page_follow_link_light,
473 .put_link = page_put_link,
474 };
475
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