xref: /openbmc/linux/fs/nilfs2/namei.c (revision dfb55de8) 
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 #include "export.h"
44 
45 #define NILFS_FID_SIZE_NON_CONNECTABLE \
46 	(offsetof(struct nilfs_fid, parent_gen) / 4)
47 #define NILFS_FID_SIZE_CONNECTABLE	(sizeof(struct nilfs_fid) / 4)
48 
49 static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
50 {
51 	int err = nilfs_add_link(dentry, inode);
52 	if (!err) {
53 		d_instantiate(dentry, inode);
54 		return 0;
55 	}
56 	inode_dec_link_count(inode);
57 	iput(inode);
58 	return err;
59 }
60 
61 /*
62  * Methods themselves.
63  */
64 
65 static struct dentry *
66 nilfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
67 {
68 	struct inode *inode;
69 	ino_t ino;
70 
71 	if (dentry->d_name.len > NILFS_NAME_LEN)
72 		return ERR_PTR(-ENAMETOOLONG);
73 
74 	ino = nilfs_inode_by_name(dir, &dentry->d_name);
75 	inode = NULL;
76 	if (ino) {
77 		inode = nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino);
78 		if (IS_ERR(inode))
79 			return ERR_CAST(inode);
80 	}
81 	return d_splice_alias(inode, dentry);
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  */
92 static int nilfs_create(struct inode *dir, struct dentry *dentry, int mode,
93 			struct nameidata *nd)
94 {
95 	struct inode *inode;
96 	struct nilfs_transaction_info ti;
97 	int err;
98 
99 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
100 	if (err)
101 		return err;
102 	inode = nilfs_new_inode(dir, mode);
103 	err = PTR_ERR(inode);
104 	if (!IS_ERR(inode)) {
105 		inode->i_op = &nilfs_file_inode_operations;
106 		inode->i_fop = &nilfs_file_operations;
107 		inode->i_mapping->a_ops = &nilfs_aops;
108 		nilfs_mark_inode_dirty(inode);
109 		err = nilfs_add_nondir(dentry, inode);
110 	}
111 	if (!err)
112 		err = nilfs_transaction_commit(dir->i_sb);
113 	else
114 		nilfs_transaction_abort(dir->i_sb);
115 
116 	return err;
117 }
118 
119 static int
120 nilfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
121 {
122 	struct inode *inode;
123 	struct nilfs_transaction_info ti;
124 	int err;
125 
126 	if (!new_valid_dev(rdev))
127 		return -EINVAL;
128 
129 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
130 	if (err)
131 		return err;
132 	inode = nilfs_new_inode(dir, mode);
133 	err = PTR_ERR(inode);
134 	if (!IS_ERR(inode)) {
135 		init_special_inode(inode, inode->i_mode, rdev);
136 		nilfs_mark_inode_dirty(inode);
137 		err = nilfs_add_nondir(dentry, inode);
138 	}
139 	if (!err)
140 		err = nilfs_transaction_commit(dir->i_sb);
141 	else
142 		nilfs_transaction_abort(dir->i_sb);
143 
144 	return err;
145 }
146 
147 static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
148 			 const char *symname)
149 {
150 	struct nilfs_transaction_info ti;
151 	struct super_block *sb = dir->i_sb;
152 	unsigned l = strlen(symname)+1;
153 	struct inode *inode;
154 	int err;
155 
156 	if (l > sb->s_blocksize)
157 		return -ENAMETOOLONG;
158 
159 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
160 	if (err)
161 		return err;
162 
163 	inode = nilfs_new_inode(dir, S_IFLNK | S_IRWXUGO);
164 	err = PTR_ERR(inode);
165 	if (IS_ERR(inode))
166 		goto out;
167 
168 	/* slow symlink */
169 	inode->i_op = &nilfs_symlink_inode_operations;
170 	inode->i_mapping->a_ops = &nilfs_aops;
171 	err = page_symlink(inode, symname, l);
172 	if (err)
173 		goto out_fail;
174 
175 	/* mark_inode_dirty(inode); */
176 	/* page_symlink() do this */
177 
178 	err = nilfs_add_nondir(dentry, inode);
179 out:
180 	if (!err)
181 		err = nilfs_transaction_commit(dir->i_sb);
182 	else
183 		nilfs_transaction_abort(dir->i_sb);
184 
185 	return err;
186 
187 out_fail:
188 	drop_nlink(inode);
189 	nilfs_mark_inode_dirty(inode);
190 	iput(inode);
191 	goto out;
192 }
193 
194 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
195 		      struct dentry *dentry)
196 {
197 	struct inode *inode = old_dentry->d_inode;
198 	struct nilfs_transaction_info ti;
199 	int err;
200 
201 	if (inode->i_nlink >= NILFS_LINK_MAX)
202 		return -EMLINK;
203 
204 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
205 	if (err)
206 		return err;
207 
208 	inode->i_ctime = CURRENT_TIME;
209 	inode_inc_link_count(inode);
210 	ihold(inode);
211 
212 	err = nilfs_add_nondir(dentry, inode);
213 	if (!err)
214 		err = nilfs_transaction_commit(dir->i_sb);
215 	else
216 		nilfs_transaction_abort(dir->i_sb);
217 
218 	return err;
219 }
220 
221 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
222 {
223 	struct inode *inode;
224 	struct nilfs_transaction_info ti;
225 	int err;
226 
227 	if (dir->i_nlink >= NILFS_LINK_MAX)
228 		return -EMLINK;
229 
230 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
231 	if (err)
232 		return err;
233 
234 	inc_nlink(dir);
235 
236 	inode = nilfs_new_inode(dir, S_IFDIR | mode);
237 	err = PTR_ERR(inode);
238 	if (IS_ERR(inode))
239 		goto out_dir;
240 
241 	inode->i_op = &nilfs_dir_inode_operations;
242 	inode->i_fop = &nilfs_dir_operations;
243 	inode->i_mapping->a_ops = &nilfs_aops;
244 
245 	inc_nlink(inode);
246 
247 	err = nilfs_make_empty(inode, dir);
248 	if (err)
249 		goto out_fail;
250 
251 	err = nilfs_add_link(dentry, inode);
252 	if (err)
253 		goto out_fail;
254 
255 	nilfs_mark_inode_dirty(inode);
256 	d_instantiate(dentry, inode);
257 out:
258 	if (!err)
259 		err = nilfs_transaction_commit(dir->i_sb);
260 	else
261 		nilfs_transaction_abort(dir->i_sb);
262 
263 	return err;
264 
265 out_fail:
266 	drop_nlink(inode);
267 	drop_nlink(inode);
268 	nilfs_mark_inode_dirty(inode);
269 	iput(inode);
270 out_dir:
271 	drop_nlink(dir);
272 	nilfs_mark_inode_dirty(dir);
273 	goto out;
274 }
275 
276 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
277 {
278 	struct inode *inode;
279 	struct nilfs_dir_entry *de;
280 	struct page *page;
281 	int err;
282 
283 	err = -ENOENT;
284 	de = nilfs_find_entry(dir, &dentry->d_name, &page);
285 	if (!de)
286 		goto out;
287 
288 	inode = dentry->d_inode;
289 	err = -EIO;
290 	if (le64_to_cpu(de->inode) != inode->i_ino)
291 		goto out;
292 
293 	if (!inode->i_nlink) {
294 		nilfs_warning(inode->i_sb, __func__,
295 			      "deleting nonexistent file (%lu), %d\n",
296 			      inode->i_ino, inode->i_nlink);
297 		inode->i_nlink = 1;
298 	}
299 	err = nilfs_delete_entry(de, page);
300 	if (err)
301 		goto out;
302 
303 	inode->i_ctime = dir->i_ctime;
304 	drop_nlink(inode);
305 	err = 0;
306 out:
307 	return err;
308 }
309 
310 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
311 {
312 	struct nilfs_transaction_info ti;
313 	int err;
314 
315 	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
316 	if (err)
317 		return err;
318 
319 	err = nilfs_do_unlink(dir, dentry);
320 
321 	if (!err) {
322 		nilfs_mark_inode_dirty(dir);
323 		nilfs_mark_inode_dirty(dentry->d_inode);
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_do_unlink(dir, dentry);
344 		if (!err) {
345 			inode->i_size = 0;
346 			drop_nlink(inode);
347 			nilfs_mark_inode_dirty(inode);
348 			drop_nlink(dir);
349 			nilfs_mark_inode_dirty(dir);
350 		}
351 	}
352 	if (!err)
353 		err = nilfs_transaction_commit(dir->i_sb);
354 	else
355 		nilfs_transaction_abort(dir->i_sb);
356 
357 	return err;
358 }
359 
360 static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
361 			struct inode *new_dir,	struct dentry *new_dentry)
362 {
363 	struct inode *old_inode = old_dentry->d_inode;
364 	struct inode *new_inode = new_dentry->d_inode;
365 	struct page *dir_page = NULL;
366 	struct nilfs_dir_entry *dir_de = NULL;
367 	struct page *old_page;
368 	struct nilfs_dir_entry *old_de;
369 	struct nilfs_transaction_info ti;
370 	int err;
371 
372 	err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
373 	if (unlikely(err))
374 		return err;
375 
376 	err = -ENOENT;
377 	old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_page);
378 	if (!old_de)
379 		goto out;
380 
381 	if (S_ISDIR(old_inode->i_mode)) {
382 		err = -EIO;
383 		dir_de = nilfs_dotdot(old_inode, &dir_page);
384 		if (!dir_de)
385 			goto out_old;
386 	}
387 
388 	if (new_inode) {
389 		struct page *new_page;
390 		struct nilfs_dir_entry *new_de;
391 
392 		err = -ENOTEMPTY;
393 		if (dir_de && !nilfs_empty_dir(new_inode))
394 			goto out_dir;
395 
396 		err = -ENOENT;
397 		new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, &new_page);
398 		if (!new_de)
399 			goto out_dir;
400 		nilfs_set_link(new_dir, new_de, new_page, old_inode);
401 		nilfs_mark_inode_dirty(new_dir);
402 		new_inode->i_ctime = CURRENT_TIME;
403 		if (dir_de)
404 			drop_nlink(new_inode);
405 		drop_nlink(new_inode);
406 		nilfs_mark_inode_dirty(new_inode);
407 	} else {
408 		if (dir_de) {
409 			err = -EMLINK;
410 			if (new_dir->i_nlink >= NILFS_LINK_MAX)
411 				goto out_dir;
412 		}
413 		err = nilfs_add_link(new_dentry, old_inode);
414 		if (err)
415 			goto out_dir;
416 		if (dir_de) {
417 			inc_nlink(new_dir);
418 			nilfs_mark_inode_dirty(new_dir);
419 		}
420 	}
421 
422 	/*
423 	 * Like most other Unix systems, set the ctime for inodes on a
424 	 * rename.
425 	 */
426 	old_inode->i_ctime = CURRENT_TIME;
427 
428 	nilfs_delete_entry(old_de, old_page);
429 
430 	if (dir_de) {
431 		nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
432 		drop_nlink(old_dir);
433 	}
434 	nilfs_mark_inode_dirty(old_dir);
435 	nilfs_mark_inode_dirty(old_inode);
436 
437 	err = nilfs_transaction_commit(old_dir->i_sb);
438 	return err;
439 
440 out_dir:
441 	if (dir_de) {
442 		kunmap(dir_page);
443 		page_cache_release(dir_page);
444 	}
445 out_old:
446 	kunmap(old_page);
447 	page_cache_release(old_page);
448 out:
449 	nilfs_transaction_abort(old_dir->i_sb);
450 	return err;
451 }
452 
453 /*
454  * Export operations
455  */
456 static struct dentry *nilfs_get_parent(struct dentry *child)
457 {
458 	unsigned long ino;
459 	struct inode *inode;
460 	struct qstr dotdot = {.name = "..", .len = 2};
461 	struct nilfs_root *root;
462 
463 	ino = nilfs_inode_by_name(child->d_inode, &dotdot);
464 	if (!ino)
465 		return ERR_PTR(-ENOENT);
466 
467 	root = NILFS_I(child->d_inode)->i_root;
468 
469 	inode = nilfs_iget(child->d_inode->i_sb, root, ino);
470 	if (IS_ERR(inode))
471 		return ERR_CAST(inode);
472 
473 	return d_obtain_alias(inode);
474 }
475 
476 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
477 				       u64 ino, u32 gen)
478 {
479 	struct nilfs_root *root;
480 	struct inode *inode;
481 
482 	if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
483 		return ERR_PTR(-ESTALE);
484 
485 	root = nilfs_lookup_root(sb->s_fs_info, cno);
486 	if (!root)
487 		return ERR_PTR(-ESTALE);
488 
489 	inode = nilfs_iget(sb, root, ino);
490 	nilfs_put_root(root);
491 
492 	if (IS_ERR(inode))
493 		return ERR_CAST(inode);
494 	if (gen && inode->i_generation != gen) {
495 		iput(inode);
496 		return ERR_PTR(-ESTALE);
497 	}
498 	return d_obtain_alias(inode);
499 }
500 
501 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
502 					 int fh_len, int fh_type)
503 {
504 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
505 
506 	if ((fh_len != NILFS_FID_SIZE_NON_CONNECTABLE &&
507 	     fh_len != NILFS_FID_SIZE_CONNECTABLE) ||
508 	    (fh_type != FILEID_NILFS_WITH_PARENT &&
509 	     fh_type != FILEID_NILFS_WITHOUT_PARENT))
510 		return NULL;
511 
512 	return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
513 }
514 
515 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
516 					 int fh_len, int fh_type)
517 {
518 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
519 
520 	if (fh_len != NILFS_FID_SIZE_CONNECTABLE ||
521 	    fh_type != FILEID_NILFS_WITH_PARENT)
522 		return NULL;
523 
524 	return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
525 }
526 
527 static int nilfs_encode_fh(struct dentry *dentry, __u32 *fh, int *lenp,
528 			   int connectable)
529 {
530 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
531 	struct inode *inode = dentry->d_inode;
532 	struct nilfs_root *root = NILFS_I(inode)->i_root;
533 	int type;
534 
535 	if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE ||
536 	    (connectable && *lenp < NILFS_FID_SIZE_CONNECTABLE))
537 		return 255;
538 
539 	fid->cno = root->cno;
540 	fid->ino = inode->i_ino;
541 	fid->gen = inode->i_generation;
542 
543 	if (connectable && !S_ISDIR(inode->i_mode)) {
544 		struct inode *parent;
545 
546 		spin_lock(&dentry->d_lock);
547 		parent = dentry->d_parent->d_inode;
548 		fid->parent_ino = parent->i_ino;
549 		fid->parent_gen = parent->i_generation;
550 		spin_unlock(&dentry->d_lock);
551 
552 		type = FILEID_NILFS_WITH_PARENT;
553 		*lenp = NILFS_FID_SIZE_CONNECTABLE;
554 	} else {
555 		type = FILEID_NILFS_WITHOUT_PARENT;
556 		*lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
557 	}
558 
559 	return type;
560 }
561 
562 const struct inode_operations nilfs_dir_inode_operations = {
563 	.create		= nilfs_create,
564 	.lookup		= nilfs_lookup,
565 	.link		= nilfs_link,
566 	.unlink		= nilfs_unlink,
567 	.symlink	= nilfs_symlink,
568 	.mkdir		= nilfs_mkdir,
569 	.rmdir		= nilfs_rmdir,
570 	.mknod		= nilfs_mknod,
571 	.rename		= nilfs_rename,
572 	.setattr	= nilfs_setattr,
573 	.permission	= nilfs_permission,
574 	.fiemap		= nilfs_fiemap,
575 };
576 
577 const struct inode_operations nilfs_special_inode_operations = {
578 	.setattr	= nilfs_setattr,
579 	.permission	= nilfs_permission,
580 };
581 
582 const struct inode_operations nilfs_symlink_inode_operations = {
583 	.readlink	= generic_readlink,
584 	.follow_link	= page_follow_link_light,
585 	.put_link	= page_put_link,
586 	.permission     = nilfs_permission,
587 };
588 
589 const struct export_operations nilfs_export_ops = {
590 	.encode_fh = nilfs_encode_fh,
591 	.fh_to_dentry = nilfs_fh_to_dentry,
592 	.fh_to_parent = nilfs_fh_to_parent,
593 	.get_parent = nilfs_get_parent,
594 };
595