xref: /openbmc/linux/fs/nilfs2/namei.c (revision 18bb1db3) 
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 = ino ? nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino) : NULL;
76 	return d_splice_alias(inode, dentry);
77 }
78 
79 /*
80  * By the time this is called, we already have created
81  * the directory cache entry for the new file, but it
82  * is so far negative - it has no inode.
83  *
84  * If the create succeeds, we fill in the inode information
85  * with d_instantiate().
86  */
87 static int nilfs_create(struct inode *dir, struct dentry *dentry, int mode,
88 			struct nameidata *nd)
89 {
90 	struct inode *inode;
91 	struct nilfs_transaction_info ti;
92 	int err;
93 
94 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
95 	if (err)
96 		return err;
97 	inode = nilfs_new_inode(dir, mode);
98 	err = PTR_ERR(inode);
99 	if (!IS_ERR(inode)) {
100 		inode->i_op = &nilfs_file_inode_operations;
101 		inode->i_fop = &nilfs_file_operations;
102 		inode->i_mapping->a_ops = &nilfs_aops;
103 		nilfs_mark_inode_dirty(inode);
104 		err = nilfs_add_nondir(dentry, inode);
105 	}
106 	if (!err)
107 		err = nilfs_transaction_commit(dir->i_sb);
108 	else
109 		nilfs_transaction_abort(dir->i_sb);
110 
111 	return err;
112 }
113 
114 static int
115 nilfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
116 {
117 	struct inode *inode;
118 	struct nilfs_transaction_info ti;
119 	int err;
120 
121 	if (!new_valid_dev(rdev))
122 		return -EINVAL;
123 
124 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
125 	if (err)
126 		return err;
127 	inode = nilfs_new_inode(dir, mode);
128 	err = PTR_ERR(inode);
129 	if (!IS_ERR(inode)) {
130 		init_special_inode(inode, inode->i_mode, rdev);
131 		nilfs_mark_inode_dirty(inode);
132 		err = nilfs_add_nondir(dentry, inode);
133 	}
134 	if (!err)
135 		err = nilfs_transaction_commit(dir->i_sb);
136 	else
137 		nilfs_transaction_abort(dir->i_sb);
138 
139 	return err;
140 }
141 
142 static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
143 			 const char *symname)
144 {
145 	struct nilfs_transaction_info ti;
146 	struct super_block *sb = dir->i_sb;
147 	unsigned l = strlen(symname)+1;
148 	struct inode *inode;
149 	int err;
150 
151 	if (l > sb->s_blocksize)
152 		return -ENAMETOOLONG;
153 
154 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
155 	if (err)
156 		return err;
157 
158 	inode = nilfs_new_inode(dir, S_IFLNK | S_IRWXUGO);
159 	err = PTR_ERR(inode);
160 	if (IS_ERR(inode))
161 		goto out;
162 
163 	/* slow symlink */
164 	inode->i_op = &nilfs_symlink_inode_operations;
165 	inode->i_mapping->a_ops = &nilfs_aops;
166 	err = page_symlink(inode, symname, l);
167 	if (err)
168 		goto out_fail;
169 
170 	/* mark_inode_dirty(inode); */
171 	/* page_symlink() do this */
172 
173 	err = nilfs_add_nondir(dentry, inode);
174 out:
175 	if (!err)
176 		err = nilfs_transaction_commit(dir->i_sb);
177 	else
178 		nilfs_transaction_abort(dir->i_sb);
179 
180 	return err;
181 
182 out_fail:
183 	drop_nlink(inode);
184 	nilfs_mark_inode_dirty(inode);
185 	iput(inode);
186 	goto out;
187 }
188 
189 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
190 		      struct dentry *dentry)
191 {
192 	struct inode *inode = old_dentry->d_inode;
193 	struct nilfs_transaction_info ti;
194 	int err;
195 
196 	if (inode->i_nlink >= NILFS_LINK_MAX)
197 		return -EMLINK;
198 
199 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
200 	if (err)
201 		return err;
202 
203 	inode->i_ctime = CURRENT_TIME;
204 	inode_inc_link_count(inode);
205 	ihold(inode);
206 
207 	err = nilfs_add_nondir(dentry, inode);
208 	if (!err)
209 		err = nilfs_transaction_commit(dir->i_sb);
210 	else
211 		nilfs_transaction_abort(dir->i_sb);
212 
213 	return err;
214 }
215 
216 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
217 {
218 	struct inode *inode;
219 	struct nilfs_transaction_info ti;
220 	int err;
221 
222 	if (dir->i_nlink >= NILFS_LINK_MAX)
223 		return -EMLINK;
224 
225 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
226 	if (err)
227 		return err;
228 
229 	inc_nlink(dir);
230 
231 	inode = nilfs_new_inode(dir, S_IFDIR | mode);
232 	err = PTR_ERR(inode);
233 	if (IS_ERR(inode))
234 		goto out_dir;
235 
236 	inode->i_op = &nilfs_dir_inode_operations;
237 	inode->i_fop = &nilfs_dir_operations;
238 	inode->i_mapping->a_ops = &nilfs_aops;
239 
240 	inc_nlink(inode);
241 
242 	err = nilfs_make_empty(inode, dir);
243 	if (err)
244 		goto out_fail;
245 
246 	err = nilfs_add_link(dentry, inode);
247 	if (err)
248 		goto out_fail;
249 
250 	nilfs_mark_inode_dirty(inode);
251 	d_instantiate(dentry, inode);
252 out:
253 	if (!err)
254 		err = nilfs_transaction_commit(dir->i_sb);
255 	else
256 		nilfs_transaction_abort(dir->i_sb);
257 
258 	return err;
259 
260 out_fail:
261 	drop_nlink(inode);
262 	drop_nlink(inode);
263 	nilfs_mark_inode_dirty(inode);
264 	iput(inode);
265 out_dir:
266 	drop_nlink(dir);
267 	nilfs_mark_inode_dirty(dir);
268 	goto out;
269 }
270 
271 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
272 {
273 	struct inode *inode;
274 	struct nilfs_dir_entry *de;
275 	struct page *page;
276 	int err;
277 
278 	err = -ENOENT;
279 	de = nilfs_find_entry(dir, &dentry->d_name, &page);
280 	if (!de)
281 		goto out;
282 
283 	inode = dentry->d_inode;
284 	err = -EIO;
285 	if (le64_to_cpu(de->inode) != inode->i_ino)
286 		goto out;
287 
288 	if (!inode->i_nlink) {
289 		nilfs_warning(inode->i_sb, __func__,
290 			      "deleting nonexistent file (%lu), %d\n",
291 			      inode->i_ino, inode->i_nlink);
292 		set_nlink(inode, 1);
293 	}
294 	err = nilfs_delete_entry(de, page);
295 	if (err)
296 		goto out;
297 
298 	inode->i_ctime = dir->i_ctime;
299 	drop_nlink(inode);
300 	err = 0;
301 out:
302 	return err;
303 }
304 
305 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
306 {
307 	struct nilfs_transaction_info ti;
308 	int err;
309 
310 	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
311 	if (err)
312 		return err;
313 
314 	err = nilfs_do_unlink(dir, dentry);
315 
316 	if (!err) {
317 		nilfs_mark_inode_dirty(dir);
318 		nilfs_mark_inode_dirty(dentry->d_inode);
319 		err = nilfs_transaction_commit(dir->i_sb);
320 	} else
321 		nilfs_transaction_abort(dir->i_sb);
322 
323 	return err;
324 }
325 
326 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
327 {
328 	struct inode *inode = dentry->d_inode;
329 	struct nilfs_transaction_info ti;
330 	int err;
331 
332 	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
333 	if (err)
334 		return err;
335 
336 	err = -ENOTEMPTY;
337 	if (nilfs_empty_dir(inode)) {
338 		err = nilfs_do_unlink(dir, dentry);
339 		if (!err) {
340 			inode->i_size = 0;
341 			drop_nlink(inode);
342 			nilfs_mark_inode_dirty(inode);
343 			drop_nlink(dir);
344 			nilfs_mark_inode_dirty(dir);
345 		}
346 	}
347 	if (!err)
348 		err = nilfs_transaction_commit(dir->i_sb);
349 	else
350 		nilfs_transaction_abort(dir->i_sb);
351 
352 	return err;
353 }
354 
355 static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
356 			struct inode *new_dir,	struct dentry *new_dentry)
357 {
358 	struct inode *old_inode = old_dentry->d_inode;
359 	struct inode *new_inode = new_dentry->d_inode;
360 	struct page *dir_page = NULL;
361 	struct nilfs_dir_entry *dir_de = NULL;
362 	struct page *old_page;
363 	struct nilfs_dir_entry *old_de;
364 	struct nilfs_transaction_info ti;
365 	int err;
366 
367 	err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
368 	if (unlikely(err))
369 		return err;
370 
371 	err = -ENOENT;
372 	old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_page);
373 	if (!old_de)
374 		goto out;
375 
376 	if (S_ISDIR(old_inode->i_mode)) {
377 		err = -EIO;
378 		dir_de = nilfs_dotdot(old_inode, &dir_page);
379 		if (!dir_de)
380 			goto out_old;
381 	}
382 
383 	if (new_inode) {
384 		struct page *new_page;
385 		struct nilfs_dir_entry *new_de;
386 
387 		err = -ENOTEMPTY;
388 		if (dir_de && !nilfs_empty_dir(new_inode))
389 			goto out_dir;
390 
391 		err = -ENOENT;
392 		new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, &new_page);
393 		if (!new_de)
394 			goto out_dir;
395 		nilfs_set_link(new_dir, new_de, new_page, old_inode);
396 		nilfs_mark_inode_dirty(new_dir);
397 		new_inode->i_ctime = CURRENT_TIME;
398 		if (dir_de)
399 			drop_nlink(new_inode);
400 		drop_nlink(new_inode);
401 		nilfs_mark_inode_dirty(new_inode);
402 	} else {
403 		if (dir_de) {
404 			err = -EMLINK;
405 			if (new_dir->i_nlink >= NILFS_LINK_MAX)
406 				goto out_dir;
407 		}
408 		err = nilfs_add_link(new_dentry, old_inode);
409 		if (err)
410 			goto out_dir;
411 		if (dir_de) {
412 			inc_nlink(new_dir);
413 			nilfs_mark_inode_dirty(new_dir);
414 		}
415 	}
416 
417 	/*
418 	 * Like most other Unix systems, set the ctime for inodes on a
419 	 * rename.
420 	 */
421 	old_inode->i_ctime = CURRENT_TIME;
422 
423 	nilfs_delete_entry(old_de, old_page);
424 
425 	if (dir_de) {
426 		nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
427 		drop_nlink(old_dir);
428 	}
429 	nilfs_mark_inode_dirty(old_dir);
430 	nilfs_mark_inode_dirty(old_inode);
431 
432 	err = nilfs_transaction_commit(old_dir->i_sb);
433 	return err;
434 
435 out_dir:
436 	if (dir_de) {
437 		kunmap(dir_page);
438 		page_cache_release(dir_page);
439 	}
440 out_old:
441 	kunmap(old_page);
442 	page_cache_release(old_page);
443 out:
444 	nilfs_transaction_abort(old_dir->i_sb);
445 	return err;
446 }
447 
448 /*
449  * Export operations
450  */
451 static struct dentry *nilfs_get_parent(struct dentry *child)
452 {
453 	unsigned long ino;
454 	struct inode *inode;
455 	struct qstr dotdot = {.name = "..", .len = 2};
456 	struct nilfs_root *root;
457 
458 	ino = nilfs_inode_by_name(child->d_inode, &dotdot);
459 	if (!ino)
460 		return ERR_PTR(-ENOENT);
461 
462 	root = NILFS_I(child->d_inode)->i_root;
463 
464 	inode = nilfs_iget(child->d_inode->i_sb, root, ino);
465 	if (IS_ERR(inode))
466 		return ERR_CAST(inode);
467 
468 	return d_obtain_alias(inode);
469 }
470 
471 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
472 				       u64 ino, u32 gen)
473 {
474 	struct nilfs_root *root;
475 	struct inode *inode;
476 
477 	if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
478 		return ERR_PTR(-ESTALE);
479 
480 	root = nilfs_lookup_root(sb->s_fs_info, cno);
481 	if (!root)
482 		return ERR_PTR(-ESTALE);
483 
484 	inode = nilfs_iget(sb, root, ino);
485 	nilfs_put_root(root);
486 
487 	if (IS_ERR(inode))
488 		return ERR_CAST(inode);
489 	if (gen && inode->i_generation != gen) {
490 		iput(inode);
491 		return ERR_PTR(-ESTALE);
492 	}
493 	return d_obtain_alias(inode);
494 }
495 
496 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
497 					 int fh_len, int fh_type)
498 {
499 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
500 
501 	if ((fh_len != NILFS_FID_SIZE_NON_CONNECTABLE &&
502 	     fh_len != NILFS_FID_SIZE_CONNECTABLE) ||
503 	    (fh_type != FILEID_NILFS_WITH_PARENT &&
504 	     fh_type != FILEID_NILFS_WITHOUT_PARENT))
505 		return NULL;
506 
507 	return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
508 }
509 
510 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
511 					 int fh_len, int fh_type)
512 {
513 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
514 
515 	if (fh_len != NILFS_FID_SIZE_CONNECTABLE ||
516 	    fh_type != FILEID_NILFS_WITH_PARENT)
517 		return NULL;
518 
519 	return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
520 }
521 
522 static int nilfs_encode_fh(struct dentry *dentry, __u32 *fh, int *lenp,
523 			   int connectable)
524 {
525 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
526 	struct inode *inode = dentry->d_inode;
527 	struct nilfs_root *root = NILFS_I(inode)->i_root;
528 	int type;
529 
530 	if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE ||
531 	    (connectable && *lenp < NILFS_FID_SIZE_CONNECTABLE))
532 		return 255;
533 
534 	fid->cno = root->cno;
535 	fid->ino = inode->i_ino;
536 	fid->gen = inode->i_generation;
537 
538 	if (connectable && !S_ISDIR(inode->i_mode)) {
539 		struct inode *parent;
540 
541 		spin_lock(&dentry->d_lock);
542 		parent = dentry->d_parent->d_inode;
543 		fid->parent_ino = parent->i_ino;
544 		fid->parent_gen = parent->i_generation;
545 		spin_unlock(&dentry->d_lock);
546 
547 		type = FILEID_NILFS_WITH_PARENT;
548 		*lenp = NILFS_FID_SIZE_CONNECTABLE;
549 	} else {
550 		type = FILEID_NILFS_WITHOUT_PARENT;
551 		*lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
552 	}
553 
554 	return type;
555 }
556 
557 const struct inode_operations nilfs_dir_inode_operations = {
558 	.create		= nilfs_create,
559 	.lookup		= nilfs_lookup,
560 	.link		= nilfs_link,
561 	.unlink		= nilfs_unlink,
562 	.symlink	= nilfs_symlink,
563 	.mkdir		= nilfs_mkdir,
564 	.rmdir		= nilfs_rmdir,
565 	.mknod		= nilfs_mknod,
566 	.rename		= nilfs_rename,
567 	.setattr	= nilfs_setattr,
568 	.permission	= nilfs_permission,
569 	.fiemap		= nilfs_fiemap,
570 };
571 
572 const struct inode_operations nilfs_special_inode_operations = {
573 	.setattr	= nilfs_setattr,
574 	.permission	= nilfs_permission,
575 };
576 
577 const struct inode_operations nilfs_symlink_inode_operations = {
578 	.readlink	= generic_readlink,
579 	.follow_link	= page_follow_link_light,
580 	.put_link	= page_put_link,
581 	.permission     = nilfs_permission,
582 };
583 
584 const struct export_operations nilfs_export_ops = {
585 	.encode_fh = nilfs_encode_fh,
586 	.fh_to_dentry = nilfs_fh_to_dentry,
587 	.fh_to_parent = nilfs_fh_to_parent,
588 	.get_parent = nilfs_get_parent,
589 };
590