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 * Modified for NILFS by Amagai Yoshiji and Ryusuke Konishi.
17 */
18 /*
19 * linux/fs/ext2/namei.c
20 *
21 * Copyright (C) 1992, 1993, 1994, 1995
22 * Remy Card (card@masi.ibp.fr)
23 * Laboratoire MASI - Institut Blaise Pascal
24 * Universite Pierre et Marie Curie (Paris VI)
25 *
26 * from
27 *
28 * linux/fs/minix/namei.c
29 *
30 * Copyright (C) 1991, 1992 Linus Torvalds
31 *
32 * Big-endian to little-endian byte-swapping/bitmaps by
33 * David S. Miller (davem@caip.rutgers.edu), 1995
34 */
35
36 #include <linux/pagemap.h>
37 #include "nilfs.h"
38 #include "export.h"
39
40 #define NILFS_FID_SIZE_NON_CONNECTABLE \
41 (offsetof(struct nilfs_fid, parent_gen) / 4)
42 #define NILFS_FID_SIZE_CONNECTABLE (sizeof(struct nilfs_fid) / 4)
43
nilfs_add_nondir(struct dentry * dentry,struct inode * inode)44 static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
45 {
46 int err = nilfs_add_link(dentry, inode);
47
48 if (!err) {
49 d_instantiate(dentry, inode);
50 unlock_new_inode(inode);
51 return 0;
52 }
53 inode_dec_link_count(inode);
54 unlock_new_inode(inode);
55 iput(inode);
56 return err;
57 }
58
59 /*
60 * Methods themselves.
61 */
62
63 static struct dentry *
nilfs_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)64 nilfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
65 {
66 struct inode *inode;
67 ino_t ino;
68
69 if (dentry->d_name.len > NILFS_NAME_LEN)
70 return ERR_PTR(-ENAMETOOLONG);
71
72 ino = nilfs_inode_by_name(dir, &dentry->d_name);
73 inode = ino ? nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino) : NULL;
74 return d_splice_alias(inode, dentry);
75 }
76
77 /*
78 * By the time this is called, we already have created
79 * the directory cache entry for the new file, but it
80 * is so far negative - it has no inode.
81 *
82 * If the create succeeds, we fill in the inode information
83 * with d_instantiate().
84 */
nilfs_create(struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)85 static int nilfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
86 bool excl)
87 {
88 struct inode *inode;
89 struct nilfs_transaction_info ti;
90 int err;
91
92 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
93 if (err)
94 return err;
95 inode = nilfs_new_inode(dir, mode);
96 err = PTR_ERR(inode);
97 if (!IS_ERR(inode)) {
98 inode->i_op = &nilfs_file_inode_operations;
99 inode->i_fop = &nilfs_file_operations;
100 inode->i_mapping->a_ops = &nilfs_aops;
101 nilfs_mark_inode_dirty(inode);
102 err = nilfs_add_nondir(dentry, inode);
103 }
104 if (!err)
105 err = nilfs_transaction_commit(dir->i_sb);
106 else
107 nilfs_transaction_abort(dir->i_sb);
108
109 return err;
110 }
111
112 static int
nilfs_mknod(struct inode * dir,struct dentry * dentry,umode_t mode,dev_t rdev)113 nilfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
114 {
115 struct inode *inode;
116 struct nilfs_transaction_info ti;
117 int err;
118
119 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
120 if (err)
121 return err;
122 inode = nilfs_new_inode(dir, mode);
123 err = PTR_ERR(inode);
124 if (!IS_ERR(inode)) {
125 init_special_inode(inode, inode->i_mode, rdev);
126 nilfs_mark_inode_dirty(inode);
127 err = nilfs_add_nondir(dentry, inode);
128 }
129 if (!err)
130 err = nilfs_transaction_commit(dir->i_sb);
131 else
132 nilfs_transaction_abort(dir->i_sb);
133
134 return err;
135 }
136
nilfs_symlink(struct inode * dir,struct dentry * dentry,const char * symname)137 static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
138 const char *symname)
139 {
140 struct nilfs_transaction_info ti;
141 struct super_block *sb = dir->i_sb;
142 unsigned int l = strlen(symname) + 1;
143 struct inode *inode;
144 int err;
145
146 if (l > sb->s_blocksize)
147 return -ENAMETOOLONG;
148
149 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
150 if (err)
151 return err;
152
153 inode = nilfs_new_inode(dir, S_IFLNK | S_IRWXUGO);
154 err = PTR_ERR(inode);
155 if (IS_ERR(inode))
156 goto out;
157
158 /* slow symlink */
159 inode->i_op = &nilfs_symlink_inode_operations;
160 inode_nohighmem(inode);
161 inode->i_mapping->a_ops = &nilfs_aops;
162 err = page_symlink(inode, symname, l);
163 if (err)
164 goto out_fail;
165
166 /* mark_inode_dirty(inode); */
167 /* page_symlink() do this */
168
169 err = nilfs_add_nondir(dentry, inode);
170 out:
171 if (!err)
172 err = nilfs_transaction_commit(dir->i_sb);
173 else
174 nilfs_transaction_abort(dir->i_sb);
175
176 return err;
177
178 out_fail:
179 drop_nlink(inode);
180 nilfs_mark_inode_dirty(inode);
181 unlock_new_inode(inode);
182 iput(inode);
183 goto out;
184 }
185
nilfs_link(struct dentry * old_dentry,struct inode * dir,struct dentry * dentry)186 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
187 struct dentry *dentry)
188 {
189 struct inode *inode = d_inode(old_dentry);
190 struct nilfs_transaction_info ti;
191 int err;
192
193 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
194 if (err)
195 return err;
196
197 inode->i_ctime = current_time(inode);
198 inode_inc_link_count(inode);
199 ihold(inode);
200
201 err = nilfs_add_link(dentry, inode);
202 if (!err) {
203 d_instantiate(dentry, inode);
204 err = nilfs_transaction_commit(dir->i_sb);
205 } else {
206 inode_dec_link_count(inode);
207 iput(inode);
208 nilfs_transaction_abort(dir->i_sb);
209 }
210
211 return err;
212 }
213
nilfs_mkdir(struct inode * dir,struct dentry * dentry,umode_t mode)214 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
215 {
216 struct inode *inode;
217 struct nilfs_transaction_info ti;
218 int err;
219
220 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
221 if (err)
222 return err;
223
224 inc_nlink(dir);
225
226 inode = nilfs_new_inode(dir, S_IFDIR | mode);
227 err = PTR_ERR(inode);
228 if (IS_ERR(inode))
229 goto out_dir;
230
231 inode->i_op = &nilfs_dir_inode_operations;
232 inode->i_fop = &nilfs_dir_operations;
233 inode->i_mapping->a_ops = &nilfs_aops;
234
235 inc_nlink(inode);
236
237 err = nilfs_make_empty(inode, dir);
238 if (err)
239 goto out_fail;
240
241 err = nilfs_add_link(dentry, inode);
242 if (err)
243 goto out_fail;
244
245 nilfs_mark_inode_dirty(inode);
246 d_instantiate(dentry, inode);
247 unlock_new_inode(inode);
248 out:
249 if (!err)
250 err = nilfs_transaction_commit(dir->i_sb);
251 else
252 nilfs_transaction_abort(dir->i_sb);
253
254 return err;
255
256 out_fail:
257 drop_nlink(inode);
258 drop_nlink(inode);
259 nilfs_mark_inode_dirty(inode);
260 unlock_new_inode(inode);
261 iput(inode);
262 out_dir:
263 drop_nlink(dir);
264 nilfs_mark_inode_dirty(dir);
265 goto out;
266 }
267
nilfs_do_unlink(struct inode * dir,struct dentry * dentry)268 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
269 {
270 struct inode *inode;
271 struct nilfs_dir_entry *de;
272 struct page *page;
273 int err;
274
275 err = -ENOENT;
276 de = nilfs_find_entry(dir, &dentry->d_name, &page);
277 if (!de)
278 goto out;
279
280 inode = d_inode(dentry);
281 err = -EIO;
282 if (le64_to_cpu(de->inode) != inode->i_ino)
283 goto out;
284
285 if (!inode->i_nlink) {
286 nilfs_msg(inode->i_sb, KERN_WARNING,
287 "deleting nonexistent file (ino=%lu), %d",
288 inode->i_ino, inode->i_nlink);
289 set_nlink(inode, 1);
290 }
291 err = nilfs_delete_entry(de, page);
292 if (err)
293 goto out;
294
295 inode->i_ctime = dir->i_ctime;
296 drop_nlink(inode);
297 err = 0;
298 out:
299 return err;
300 }
301
nilfs_unlink(struct inode * dir,struct dentry * dentry)302 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
303 {
304 struct nilfs_transaction_info ti;
305 int err;
306
307 err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
308 if (err)
309 return err;
310
311 err = nilfs_do_unlink(dir, dentry);
312
313 if (!err) {
314 nilfs_mark_inode_dirty(dir);
315 nilfs_mark_inode_dirty(d_inode(dentry));
316 err = nilfs_transaction_commit(dir->i_sb);
317 } else
318 nilfs_transaction_abort(dir->i_sb);
319
320 return err;
321 }
322
nilfs_rmdir(struct inode * dir,struct dentry * dentry)323 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
324 {
325 struct inode *inode = d_inode(dentry);
326 struct nilfs_transaction_info ti;
327 int err;
328
329 err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
330 if (err)
331 return err;
332
333 err = -ENOTEMPTY;
334 if (nilfs_empty_dir(inode)) {
335 err = nilfs_do_unlink(dir, dentry);
336 if (!err) {
337 inode->i_size = 0;
338 drop_nlink(inode);
339 nilfs_mark_inode_dirty(inode);
340 drop_nlink(dir);
341 nilfs_mark_inode_dirty(dir);
342 }
343 }
344 if (!err)
345 err = nilfs_transaction_commit(dir->i_sb);
346 else
347 nilfs_transaction_abort(dir->i_sb);
348
349 return err;
350 }
351
nilfs_rename(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry,unsigned int flags)352 static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
353 struct inode *new_dir, struct dentry *new_dentry,
354 unsigned int flags)
355 {
356 struct inode *old_inode = d_inode(old_dentry);
357 struct inode *new_inode = d_inode(new_dentry);
358 struct page *dir_page = NULL;
359 struct nilfs_dir_entry *dir_de = NULL;
360 struct page *old_page;
361 struct nilfs_dir_entry *old_de;
362 struct nilfs_transaction_info ti;
363 int err;
364
365 if (flags & ~RENAME_NOREPLACE)
366 return -EINVAL;
367
368 err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
369 if (unlikely(err))
370 return err;
371
372 err = -ENOENT;
373 old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_page);
374 if (!old_de)
375 goto out;
376
377 if (S_ISDIR(old_inode->i_mode)) {
378 err = -EIO;
379 dir_de = nilfs_dotdot(old_inode, &dir_page);
380 if (!dir_de)
381 goto out_old;
382 }
383
384 if (new_inode) {
385 struct page *new_page;
386 struct nilfs_dir_entry *new_de;
387
388 err = -ENOTEMPTY;
389 if (dir_de && !nilfs_empty_dir(new_inode))
390 goto out_dir;
391
392 err = -ENOENT;
393 new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, &new_page);
394 if (!new_de)
395 goto out_dir;
396 nilfs_set_link(new_dir, new_de, new_page, old_inode);
397 nilfs_mark_inode_dirty(new_dir);
398 new_inode->i_ctime = current_time(new_inode);
399 if (dir_de)
400 drop_nlink(new_inode);
401 drop_nlink(new_inode);
402 nilfs_mark_inode_dirty(new_inode);
403 } else {
404 err = nilfs_add_link(new_dentry, old_inode);
405 if (err)
406 goto out_dir;
407 if (dir_de) {
408 inc_nlink(new_dir);
409 nilfs_mark_inode_dirty(new_dir);
410 }
411 }
412
413 /*
414 * Like most other Unix systems, set the ctime for inodes on a
415 * rename.
416 */
417 old_inode->i_ctime = current_time(old_inode);
418
419 nilfs_delete_entry(old_de, old_page);
420
421 if (dir_de) {
422 nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
423 drop_nlink(old_dir);
424 }
425 nilfs_mark_inode_dirty(old_dir);
426 nilfs_mark_inode_dirty(old_inode);
427
428 err = nilfs_transaction_commit(old_dir->i_sb);
429 return err;
430
431 out_dir:
432 if (dir_de) {
433 kunmap(dir_page);
434 put_page(dir_page);
435 }
436 out_old:
437 kunmap(old_page);
438 put_page(old_page);
439 out:
440 nilfs_transaction_abort(old_dir->i_sb);
441 return err;
442 }
443
444 /*
445 * Export operations
446 */
nilfs_get_parent(struct dentry * child)447 static struct dentry *nilfs_get_parent(struct dentry *child)
448 {
449 unsigned long ino;
450 struct inode *inode;
451 struct qstr dotdot = QSTR_INIT("..", 2);
452 struct nilfs_root *root;
453
454 ino = nilfs_inode_by_name(d_inode(child), &dotdot);
455 if (!ino)
456 return ERR_PTR(-ENOENT);
457
458 root = NILFS_I(d_inode(child))->i_root;
459
460 inode = nilfs_iget(child->d_sb, root, ino);
461 if (IS_ERR(inode))
462 return ERR_CAST(inode);
463
464 return d_obtain_alias(inode);
465 }
466
nilfs_get_dentry(struct super_block * sb,u64 cno,u64 ino,u32 gen)467 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
468 u64 ino, u32 gen)
469 {
470 struct nilfs_root *root;
471 struct inode *inode;
472
473 if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
474 return ERR_PTR(-ESTALE);
475
476 root = nilfs_lookup_root(sb->s_fs_info, cno);
477 if (!root)
478 return ERR_PTR(-ESTALE);
479
480 inode = nilfs_iget(sb, root, ino);
481 nilfs_put_root(root);
482
483 if (IS_ERR(inode))
484 return ERR_CAST(inode);
485 if (gen && inode->i_generation != gen) {
486 iput(inode);
487 return ERR_PTR(-ESTALE);
488 }
489 return d_obtain_alias(inode);
490 }
491
nilfs_fh_to_dentry(struct super_block * sb,struct fid * fh,int fh_len,int fh_type)492 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
493 int fh_len, int fh_type)
494 {
495 struct nilfs_fid *fid = (struct nilfs_fid *)fh;
496
497 if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE ||
498 (fh_type != FILEID_NILFS_WITH_PARENT &&
499 fh_type != FILEID_NILFS_WITHOUT_PARENT))
500 return NULL;
501
502 return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
503 }
504
nilfs_fh_to_parent(struct super_block * sb,struct fid * fh,int fh_len,int fh_type)505 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
506 int fh_len, int fh_type)
507 {
508 struct nilfs_fid *fid = (struct nilfs_fid *)fh;
509
510 if (fh_len < NILFS_FID_SIZE_CONNECTABLE ||
511 fh_type != FILEID_NILFS_WITH_PARENT)
512 return NULL;
513
514 return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
515 }
516
nilfs_encode_fh(struct inode * inode,__u32 * fh,int * lenp,struct inode * parent)517 static int nilfs_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
518 struct inode *parent)
519 {
520 struct nilfs_fid *fid = (struct nilfs_fid *)fh;
521 struct nilfs_root *root = NILFS_I(inode)->i_root;
522 int type;
523
524 if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
525 *lenp = NILFS_FID_SIZE_CONNECTABLE;
526 return FILEID_INVALID;
527 }
528 if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
529 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
530 return FILEID_INVALID;
531 }
532
533 fid->cno = root->cno;
534 fid->ino = inode->i_ino;
535 fid->gen = inode->i_generation;
536
537 if (parent) {
538 fid->parent_ino = parent->i_ino;
539 fid->parent_gen = parent->i_generation;
540 type = FILEID_NILFS_WITH_PARENT;
541 *lenp = NILFS_FID_SIZE_CONNECTABLE;
542 } else {
543 type = FILEID_NILFS_WITHOUT_PARENT;
544 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
545 }
546
547 return type;
548 }
549
550 const struct inode_operations nilfs_dir_inode_operations = {
551 .create = nilfs_create,
552 .lookup = nilfs_lookup,
553 .link = nilfs_link,
554 .unlink = nilfs_unlink,
555 .symlink = nilfs_symlink,
556 .mkdir = nilfs_mkdir,
557 .rmdir = nilfs_rmdir,
558 .mknod = nilfs_mknod,
559 .rename = nilfs_rename,
560 .setattr = nilfs_setattr,
561 .permission = nilfs_permission,
562 .fiemap = nilfs_fiemap,
563 };
564
565 const struct inode_operations nilfs_special_inode_operations = {
566 .setattr = nilfs_setattr,
567 .permission = nilfs_permission,
568 };
569
570 const struct inode_operations nilfs_symlink_inode_operations = {
571 .readlink = generic_readlink,
572 .get_link = page_get_link,
573 .permission = nilfs_permission,
574 };
575
576 const struct export_operations nilfs_export_ops = {
577 .encode_fh = nilfs_encode_fh,
578 .fh_to_dentry = nilfs_fh_to_dentry,
579 .fh_to_parent = nilfs_fh_to_parent,
580 .get_parent = nilfs_get_parent,
581 };
582