1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * namei.c - NILFS pathname lookup operations.
4 *
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 *
7 * Modified for NILFS by Amagai Yoshiji and Ryusuke Konishi.
8 */
9 /*
10 * linux/fs/ext2/namei.c
11 *
12 * Copyright (C) 1992, 1993, 1994, 1995
13 * Remy Card (card@masi.ibp.fr)
14 * Laboratoire MASI - Institut Blaise Pascal
15 * Universite Pierre et Marie Curie (Paris VI)
16 *
17 * from
18 *
19 * linux/fs/minix/namei.c
20 *
21 * Copyright (C) 1991, 1992 Linus Torvalds
22 *
23 * Big-endian to little-endian byte-swapping/bitmaps by
24 * David S. Miller (davem@caip.rutgers.edu), 1995
25 */
26
27 #include <linux/pagemap.h>
28 #include "nilfs.h"
29 #include "export.h"
30
31 #define NILFS_FID_SIZE_NON_CONNECTABLE \
32 (offsetof(struct nilfs_fid, parent_gen) / 4)
33 #define NILFS_FID_SIZE_CONNECTABLE (sizeof(struct nilfs_fid) / 4)
34
nilfs_add_nondir(struct dentry * dentry,struct inode * inode)35 static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
36 {
37 int err = nilfs_add_link(dentry, inode);
38
39 if (!err) {
40 d_instantiate_new(dentry, inode);
41 return 0;
42 }
43 inode_dec_link_count(inode);
44 unlock_new_inode(inode);
45 iput(inode);
46 return err;
47 }
48
49 /*
50 * Methods themselves.
51 */
52
53 static struct dentry *
nilfs_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)54 nilfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
55 {
56 struct inode *inode;
57 ino_t ino;
58
59 if (dentry->d_name.len > NILFS_NAME_LEN)
60 return ERR_PTR(-ENAMETOOLONG);
61
62 ino = nilfs_inode_by_name(dir, &dentry->d_name);
63 inode = ino ? nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino) : NULL;
64 return d_splice_alias(inode, dentry);
65 }
66
67 /*
68 * By the time this is called, we already have created
69 * the directory cache entry for the new file, but it
70 * is so far negative - it has no inode.
71 *
72 * If the create succeeds, we fill in the inode information
73 * with d_instantiate().
74 */
nilfs_create(struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)75 static int nilfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
76 bool excl)
77 {
78 struct inode *inode;
79 struct nilfs_transaction_info ti;
80 int err;
81
82 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
83 if (err)
84 return err;
85 inode = nilfs_new_inode(dir, mode);
86 err = PTR_ERR(inode);
87 if (!IS_ERR(inode)) {
88 inode->i_op = &nilfs_file_inode_operations;
89 inode->i_fop = &nilfs_file_operations;
90 inode->i_mapping->a_ops = &nilfs_aops;
91 nilfs_mark_inode_dirty(inode);
92 err = nilfs_add_nondir(dentry, inode);
93 }
94 if (!err)
95 err = nilfs_transaction_commit(dir->i_sb);
96 else
97 nilfs_transaction_abort(dir->i_sb);
98
99 return err;
100 }
101
102 static int
nilfs_mknod(struct inode * dir,struct dentry * dentry,umode_t mode,dev_t rdev)103 nilfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
104 {
105 struct inode *inode;
106 struct nilfs_transaction_info ti;
107 int err;
108
109 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
110 if (err)
111 return err;
112 inode = nilfs_new_inode(dir, mode);
113 err = PTR_ERR(inode);
114 if (!IS_ERR(inode)) {
115 init_special_inode(inode, inode->i_mode, rdev);
116 nilfs_mark_inode_dirty(inode);
117 err = nilfs_add_nondir(dentry, inode);
118 }
119 if (!err)
120 err = nilfs_transaction_commit(dir->i_sb);
121 else
122 nilfs_transaction_abort(dir->i_sb);
123
124 return err;
125 }
126
nilfs_symlink(struct inode * dir,struct dentry * dentry,const char * symname)127 static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
128 const char *symname)
129 {
130 struct nilfs_transaction_info ti;
131 struct super_block *sb = dir->i_sb;
132 unsigned int l = strlen(symname) + 1;
133 struct inode *inode;
134 int err;
135
136 if (l > sb->s_blocksize)
137 return -ENAMETOOLONG;
138
139 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
140 if (err)
141 return err;
142
143 inode = nilfs_new_inode(dir, S_IFLNK | 0777);
144 err = PTR_ERR(inode);
145 if (IS_ERR(inode))
146 goto out;
147
148 /* slow symlink */
149 inode->i_op = &nilfs_symlink_inode_operations;
150 inode_nohighmem(inode);
151 inode->i_mapping->a_ops = &nilfs_aops;
152 err = page_symlink(inode, symname, l);
153 if (err)
154 goto out_fail;
155
156 /* mark_inode_dirty(inode); */
157 /* page_symlink() do this */
158
159 err = nilfs_add_nondir(dentry, inode);
160 out:
161 if (!err)
162 err = nilfs_transaction_commit(dir->i_sb);
163 else
164 nilfs_transaction_abort(dir->i_sb);
165
166 return err;
167
168 out_fail:
169 drop_nlink(inode);
170 nilfs_mark_inode_dirty(inode);
171 unlock_new_inode(inode);
172 iput(inode);
173 goto out;
174 }
175
nilfs_link(struct dentry * old_dentry,struct inode * dir,struct dentry * dentry)176 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
177 struct dentry *dentry)
178 {
179 struct inode *inode = d_inode(old_dentry);
180 struct nilfs_transaction_info ti;
181 int err;
182
183 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
184 if (err)
185 return err;
186
187 inode->i_ctime = current_time(inode);
188 inode_inc_link_count(inode);
189 ihold(inode);
190
191 err = nilfs_add_link(dentry, inode);
192 if (!err) {
193 d_instantiate(dentry, inode);
194 err = nilfs_transaction_commit(dir->i_sb);
195 } else {
196 inode_dec_link_count(inode);
197 iput(inode);
198 nilfs_transaction_abort(dir->i_sb);
199 }
200
201 return err;
202 }
203
nilfs_mkdir(struct inode * dir,struct dentry * dentry,umode_t mode)204 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
205 {
206 struct inode *inode;
207 struct nilfs_transaction_info ti;
208 int err;
209
210 err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
211 if (err)
212 return err;
213
214 inc_nlink(dir);
215
216 inode = nilfs_new_inode(dir, S_IFDIR | mode);
217 err = PTR_ERR(inode);
218 if (IS_ERR(inode))
219 goto out_dir;
220
221 inode->i_op = &nilfs_dir_inode_operations;
222 inode->i_fop = &nilfs_dir_operations;
223 inode->i_mapping->a_ops = &nilfs_aops;
224
225 inc_nlink(inode);
226
227 err = nilfs_make_empty(inode, dir);
228 if (err)
229 goto out_fail;
230
231 err = nilfs_add_link(dentry, inode);
232 if (err)
233 goto out_fail;
234
235 nilfs_mark_inode_dirty(inode);
236 d_instantiate_new(dentry, inode);
237 out:
238 if (!err)
239 err = nilfs_transaction_commit(dir->i_sb);
240 else
241 nilfs_transaction_abort(dir->i_sb);
242
243 return err;
244
245 out_fail:
246 drop_nlink(inode);
247 drop_nlink(inode);
248 nilfs_mark_inode_dirty(inode);
249 unlock_new_inode(inode);
250 iput(inode);
251 out_dir:
252 drop_nlink(dir);
253 nilfs_mark_inode_dirty(dir);
254 goto out;
255 }
256
nilfs_do_unlink(struct inode * dir,struct dentry * dentry)257 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
258 {
259 struct inode *inode;
260 struct nilfs_dir_entry *de;
261 struct page *page;
262 int err;
263
264 err = -ENOENT;
265 de = nilfs_find_entry(dir, &dentry->d_name, &page);
266 if (!de)
267 goto out;
268
269 inode = d_inode(dentry);
270 err = -EIO;
271 if (le64_to_cpu(de->inode) != inode->i_ino)
272 goto out;
273
274 if (!inode->i_nlink) {
275 nilfs_warn(inode->i_sb,
276 "deleting nonexistent file (ino=%lu), %d",
277 inode->i_ino, inode->i_nlink);
278 set_nlink(inode, 1);
279 }
280 err = nilfs_delete_entry(de, page);
281 if (err)
282 goto out;
283
284 inode->i_ctime = dir->i_ctime;
285 drop_nlink(inode);
286 err = 0;
287 out:
288 return err;
289 }
290
nilfs_unlink(struct inode * dir,struct dentry * dentry)291 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
292 {
293 struct nilfs_transaction_info ti;
294 int err;
295
296 err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
297 if (err)
298 return err;
299
300 err = nilfs_do_unlink(dir, dentry);
301
302 if (!err) {
303 nilfs_mark_inode_dirty(dir);
304 nilfs_mark_inode_dirty(d_inode(dentry));
305 err = nilfs_transaction_commit(dir->i_sb);
306 } else
307 nilfs_transaction_abort(dir->i_sb);
308
309 return err;
310 }
311
nilfs_rmdir(struct inode * dir,struct dentry * dentry)312 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
313 {
314 struct inode *inode = d_inode(dentry);
315 struct nilfs_transaction_info ti;
316 int err;
317
318 err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
319 if (err)
320 return err;
321
322 err = -ENOTEMPTY;
323 if (nilfs_empty_dir(inode)) {
324 err = nilfs_do_unlink(dir, dentry);
325 if (!err) {
326 inode->i_size = 0;
327 drop_nlink(inode);
328 nilfs_mark_inode_dirty(inode);
329 drop_nlink(dir);
330 nilfs_mark_inode_dirty(dir);
331 }
332 }
333 if (!err)
334 err = nilfs_transaction_commit(dir->i_sb);
335 else
336 nilfs_transaction_abort(dir->i_sb);
337
338 return err;
339 }
340
nilfs_rename(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry,unsigned int flags)341 static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
342 struct inode *new_dir, struct dentry *new_dentry,
343 unsigned int flags)
344 {
345 struct inode *old_inode = d_inode(old_dentry);
346 struct inode *new_inode = d_inode(new_dentry);
347 struct page *dir_page = NULL;
348 struct nilfs_dir_entry *dir_de = NULL;
349 struct page *old_page;
350 struct nilfs_dir_entry *old_de;
351 struct nilfs_transaction_info ti;
352 int err;
353
354 if (flags & ~RENAME_NOREPLACE)
355 return -EINVAL;
356
357 err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
358 if (unlikely(err))
359 return err;
360
361 err = -ENOENT;
362 old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_page);
363 if (!old_de)
364 goto out;
365
366 if (S_ISDIR(old_inode->i_mode)) {
367 err = -EIO;
368 dir_de = nilfs_dotdot(old_inode, &dir_page);
369 if (!dir_de)
370 goto out_old;
371 }
372
373 if (new_inode) {
374 struct page *new_page;
375 struct nilfs_dir_entry *new_de;
376
377 err = -ENOTEMPTY;
378 if (dir_de && !nilfs_empty_dir(new_inode))
379 goto out_dir;
380
381 err = -ENOENT;
382 new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, &new_page);
383 if (!new_de)
384 goto out_dir;
385 nilfs_set_link(new_dir, new_de, new_page, old_inode);
386 nilfs_mark_inode_dirty(new_dir);
387 new_inode->i_ctime = current_time(new_inode);
388 if (dir_de)
389 drop_nlink(new_inode);
390 drop_nlink(new_inode);
391 nilfs_mark_inode_dirty(new_inode);
392 } else {
393 err = nilfs_add_link(new_dentry, old_inode);
394 if (err)
395 goto out_dir;
396 if (dir_de) {
397 inc_nlink(new_dir);
398 nilfs_mark_inode_dirty(new_dir);
399 }
400 }
401
402 /*
403 * Like most other Unix systems, set the ctime for inodes on a
404 * rename.
405 */
406 old_inode->i_ctime = current_time(old_inode);
407
408 nilfs_delete_entry(old_de, old_page);
409
410 if (dir_de) {
411 nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
412 drop_nlink(old_dir);
413 }
414 nilfs_mark_inode_dirty(old_dir);
415 nilfs_mark_inode_dirty(old_inode);
416
417 err = nilfs_transaction_commit(old_dir->i_sb);
418 return err;
419
420 out_dir:
421 if (dir_de) {
422 kunmap(dir_page);
423 put_page(dir_page);
424 }
425 out_old:
426 kunmap(old_page);
427 put_page(old_page);
428 out:
429 nilfs_transaction_abort(old_dir->i_sb);
430 return err;
431 }
432
433 /*
434 * Export operations
435 */
nilfs_get_parent(struct dentry * child)436 static struct dentry *nilfs_get_parent(struct dentry *child)
437 {
438 unsigned long ino;
439 struct inode *inode;
440 struct qstr dotdot = QSTR_INIT("..", 2);
441 struct nilfs_root *root;
442
443 ino = nilfs_inode_by_name(d_inode(child), &dotdot);
444 if (!ino)
445 return ERR_PTR(-ENOENT);
446
447 root = NILFS_I(d_inode(child))->i_root;
448
449 inode = nilfs_iget(child->d_sb, root, ino);
450 if (IS_ERR(inode))
451 return ERR_CAST(inode);
452
453 return d_obtain_alias(inode);
454 }
455
nilfs_get_dentry(struct super_block * sb,u64 cno,u64 ino,u32 gen)456 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
457 u64 ino, u32 gen)
458 {
459 struct nilfs_root *root;
460 struct inode *inode;
461
462 if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
463 return ERR_PTR(-ESTALE);
464
465 root = nilfs_lookup_root(sb->s_fs_info, cno);
466 if (!root)
467 return ERR_PTR(-ESTALE);
468
469 inode = nilfs_iget(sb, root, ino);
470 nilfs_put_root(root);
471
472 if (IS_ERR(inode))
473 return ERR_CAST(inode);
474 if (gen && inode->i_generation != gen) {
475 iput(inode);
476 return ERR_PTR(-ESTALE);
477 }
478 return d_obtain_alias(inode);
479 }
480
nilfs_fh_to_dentry(struct super_block * sb,struct fid * fh,int fh_len,int fh_type)481 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
482 int fh_len, int fh_type)
483 {
484 struct nilfs_fid *fid = (struct nilfs_fid *)fh;
485
486 if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE ||
487 (fh_type != FILEID_NILFS_WITH_PARENT &&
488 fh_type != FILEID_NILFS_WITHOUT_PARENT))
489 return NULL;
490
491 return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
492 }
493
nilfs_fh_to_parent(struct super_block * sb,struct fid * fh,int fh_len,int fh_type)494 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
495 int fh_len, int fh_type)
496 {
497 struct nilfs_fid *fid = (struct nilfs_fid *)fh;
498
499 if (fh_len < NILFS_FID_SIZE_CONNECTABLE ||
500 fh_type != FILEID_NILFS_WITH_PARENT)
501 return NULL;
502
503 return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
504 }
505
nilfs_encode_fh(struct inode * inode,__u32 * fh,int * lenp,struct inode * parent)506 static int nilfs_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
507 struct inode *parent)
508 {
509 struct nilfs_fid *fid = (struct nilfs_fid *)fh;
510 struct nilfs_root *root = NILFS_I(inode)->i_root;
511 int type;
512
513 if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
514 *lenp = NILFS_FID_SIZE_CONNECTABLE;
515 return FILEID_INVALID;
516 }
517 if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
518 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
519 return FILEID_INVALID;
520 }
521
522 fid->cno = root->cno;
523 fid->ino = inode->i_ino;
524 fid->gen = inode->i_generation;
525
526 if (parent) {
527 fid->parent_ino = parent->i_ino;
528 fid->parent_gen = parent->i_generation;
529 type = FILEID_NILFS_WITH_PARENT;
530 *lenp = NILFS_FID_SIZE_CONNECTABLE;
531 } else {
532 type = FILEID_NILFS_WITHOUT_PARENT;
533 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
534 }
535
536 return type;
537 }
538
539 const struct inode_operations nilfs_dir_inode_operations = {
540 .create = nilfs_create,
541 .lookup = nilfs_lookup,
542 .link = nilfs_link,
543 .unlink = nilfs_unlink,
544 .symlink = nilfs_symlink,
545 .mkdir = nilfs_mkdir,
546 .rmdir = nilfs_rmdir,
547 .mknod = nilfs_mknod,
548 .rename = nilfs_rename,
549 .setattr = nilfs_setattr,
550 .permission = nilfs_permission,
551 .fiemap = nilfs_fiemap,
552 };
553
554 const struct inode_operations nilfs_special_inode_operations = {
555 .setattr = nilfs_setattr,
556 .permission = nilfs_permission,
557 };
558
559 const struct inode_operations nilfs_symlink_inode_operations = {
560 .get_link = page_get_link,
561 .permission = nilfs_permission,
562 };
563
564 const struct export_operations nilfs_export_ops = {
565 .encode_fh = nilfs_encode_fh,
566 .fh_to_dentry = nilfs_fh_to_dentry,
567 .fh_to_parent = nilfs_fh_to_parent,
568 .get_parent = nilfs_get_parent,
569 };
570