xref: /openbmc/linux/fs/nilfs2/namei.c (revision 4bce6fce) 
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 		unlock_new_inode(inode);
55 		return 0;
56 	}
57 	inode_dec_link_count(inode);
58 	unlock_new_inode(inode);
59 	iput(inode);
60 	return err;
61 }
62 
63 /*
64  * Methods themselves.
65  */
66 
67 static struct dentry *
68 nilfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
69 {
70 	struct inode *inode;
71 	ino_t ino;
72 
73 	if (dentry->d_name.len > NILFS_NAME_LEN)
74 		return ERR_PTR(-ENAMETOOLONG);
75 
76 	ino = nilfs_inode_by_name(dir, &dentry->d_name);
77 	inode = ino ? nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino) : NULL;
78 	return d_splice_alias(inode, dentry);
79 }
80 
81 /*
82  * By the time this is called, we already have created
83  * the directory cache entry for the new file, but it
84  * is so far negative - it has no inode.
85  *
86  * If the create succeeds, we fill in the inode information
87  * with d_instantiate().
88  */
89 static int nilfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
90 			bool excl)
91 {
92 	struct inode *inode;
93 	struct nilfs_transaction_info ti;
94 	int err;
95 
96 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
97 	if (err)
98 		return err;
99 	inode = nilfs_new_inode(dir, mode);
100 	err = PTR_ERR(inode);
101 	if (!IS_ERR(inode)) {
102 		inode->i_op = &nilfs_file_inode_operations;
103 		inode->i_fop = &nilfs_file_operations;
104 		inode->i_mapping->a_ops = &nilfs_aops;
105 		nilfs_mark_inode_dirty(inode);
106 		err = nilfs_add_nondir(dentry, inode);
107 	}
108 	if (!err)
109 		err = nilfs_transaction_commit(dir->i_sb);
110 	else
111 		nilfs_transaction_abort(dir->i_sb);
112 
113 	return err;
114 }
115 
116 static int
117 nilfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
118 {
119 	struct inode *inode;
120 	struct nilfs_transaction_info ti;
121 	int err;
122 
123 	if (!new_valid_dev(rdev))
124 		return -EINVAL;
125 
126 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
127 	if (err)
128 		return err;
129 	inode = nilfs_new_inode(dir, mode);
130 	err = PTR_ERR(inode);
131 	if (!IS_ERR(inode)) {
132 		init_special_inode(inode, inode->i_mode, rdev);
133 		nilfs_mark_inode_dirty(inode);
134 		err = nilfs_add_nondir(dentry, inode);
135 	}
136 	if (!err)
137 		err = nilfs_transaction_commit(dir->i_sb);
138 	else
139 		nilfs_transaction_abort(dir->i_sb);
140 
141 	return err;
142 }
143 
144 static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
145 			 const char *symname)
146 {
147 	struct nilfs_transaction_info ti;
148 	struct super_block *sb = dir->i_sb;
149 	unsigned l = strlen(symname)+1;
150 	struct inode *inode;
151 	int err;
152 
153 	if (l > sb->s_blocksize)
154 		return -ENAMETOOLONG;
155 
156 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
157 	if (err)
158 		return err;
159 
160 	inode = nilfs_new_inode(dir, S_IFLNK | S_IRWXUGO);
161 	err = PTR_ERR(inode);
162 	if (IS_ERR(inode))
163 		goto out;
164 
165 	/* slow symlink */
166 	inode->i_op = &nilfs_symlink_inode_operations;
167 	inode->i_mapping->a_ops = &nilfs_aops;
168 	err = page_symlink(inode, symname, l);
169 	if (err)
170 		goto out_fail;
171 
172 	/* mark_inode_dirty(inode); */
173 	/* page_symlink() do this */
174 
175 	err = nilfs_add_nondir(dentry, inode);
176 out:
177 	if (!err)
178 		err = nilfs_transaction_commit(dir->i_sb);
179 	else
180 		nilfs_transaction_abort(dir->i_sb);
181 
182 	return err;
183 
184 out_fail:
185 	drop_nlink(inode);
186 	nilfs_mark_inode_dirty(inode);
187 	unlock_new_inode(inode);
188 	iput(inode);
189 	goto out;
190 }
191 
192 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
193 		      struct dentry *dentry)
194 {
195 	struct inode *inode = d_inode(old_dentry);
196 	struct nilfs_transaction_info ti;
197 	int err;
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_link(dentry, inode);
208 	if (!err) {
209 		d_instantiate(dentry, inode);
210 		err = nilfs_transaction_commit(dir->i_sb);
211 	} else {
212 		inode_dec_link_count(inode);
213 		iput(inode);
214 		nilfs_transaction_abort(dir->i_sb);
215 	}
216 
217 	return err;
218 }
219 
220 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
221 {
222 	struct inode *inode;
223 	struct nilfs_transaction_info ti;
224 	int err;
225 
226 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
227 	if (err)
228 		return err;
229 
230 	inc_nlink(dir);
231 
232 	inode = nilfs_new_inode(dir, S_IFDIR | mode);
233 	err = PTR_ERR(inode);
234 	if (IS_ERR(inode))
235 		goto out_dir;
236 
237 	inode->i_op = &nilfs_dir_inode_operations;
238 	inode->i_fop = &nilfs_dir_operations;
239 	inode->i_mapping->a_ops = &nilfs_aops;
240 
241 	inc_nlink(inode);
242 
243 	err = nilfs_make_empty(inode, dir);
244 	if (err)
245 		goto out_fail;
246 
247 	err = nilfs_add_link(dentry, inode);
248 	if (err)
249 		goto out_fail;
250 
251 	nilfs_mark_inode_dirty(inode);
252 	d_instantiate(dentry, inode);
253 	unlock_new_inode(inode);
254 out:
255 	if (!err)
256 		err = nilfs_transaction_commit(dir->i_sb);
257 	else
258 		nilfs_transaction_abort(dir->i_sb);
259 
260 	return err;
261 
262 out_fail:
263 	drop_nlink(inode);
264 	drop_nlink(inode);
265 	nilfs_mark_inode_dirty(inode);
266 	unlock_new_inode(inode);
267 	iput(inode);
268 out_dir:
269 	drop_nlink(dir);
270 	nilfs_mark_inode_dirty(dir);
271 	goto out;
272 }
273 
274 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
275 {
276 	struct inode *inode;
277 	struct nilfs_dir_entry *de;
278 	struct page *page;
279 	int err;
280 
281 	err = -ENOENT;
282 	de = nilfs_find_entry(dir, &dentry->d_name, &page);
283 	if (!de)
284 		goto out;
285 
286 	inode = d_inode(dentry);
287 	err = -EIO;
288 	if (le64_to_cpu(de->inode) != inode->i_ino)
289 		goto out;
290 
291 	if (!inode->i_nlink) {
292 		nilfs_warning(inode->i_sb, __func__,
293 			      "deleting nonexistent file (%lu), %d\n",
294 			      inode->i_ino, inode->i_nlink);
295 		set_nlink(inode, 1);
296 	}
297 	err = nilfs_delete_entry(de, page);
298 	if (err)
299 		goto out;
300 
301 	inode->i_ctime = dir->i_ctime;
302 	drop_nlink(inode);
303 	err = 0;
304 out:
305 	return err;
306 }
307 
308 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
309 {
310 	struct nilfs_transaction_info ti;
311 	int err;
312 
313 	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
314 	if (err)
315 		return err;
316 
317 	err = nilfs_do_unlink(dir, dentry);
318 
319 	if (!err) {
320 		nilfs_mark_inode_dirty(dir);
321 		nilfs_mark_inode_dirty(d_inode(dentry));
322 		err = nilfs_transaction_commit(dir->i_sb);
323 	} else
324 		nilfs_transaction_abort(dir->i_sb);
325 
326 	return err;
327 }
328 
329 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
330 {
331 	struct inode *inode = d_inode(dentry);
332 	struct nilfs_transaction_info ti;
333 	int err;
334 
335 	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
336 	if (err)
337 		return err;
338 
339 	err = -ENOTEMPTY;
340 	if (nilfs_empty_dir(inode)) {
341 		err = nilfs_do_unlink(dir, dentry);
342 		if (!err) {
343 			inode->i_size = 0;
344 			drop_nlink(inode);
345 			nilfs_mark_inode_dirty(inode);
346 			drop_nlink(dir);
347 			nilfs_mark_inode_dirty(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 = d_inode(old_dentry);
362 	struct inode *new_inode = d_inode(new_dentry);
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->d_name, &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->d_name, &new_page);
396 		if (!new_de)
397 			goto out_dir;
398 		nilfs_set_link(new_dir, new_de, new_page, old_inode);
399 		nilfs_mark_inode_dirty(new_dir);
400 		new_inode->i_ctime = CURRENT_TIME;
401 		if (dir_de)
402 			drop_nlink(new_inode);
403 		drop_nlink(new_inode);
404 		nilfs_mark_inode_dirty(new_inode);
405 	} else {
406 		err = nilfs_add_link(new_dentry, old_inode);
407 		if (err)
408 			goto out_dir;
409 		if (dir_de) {
410 			inc_nlink(new_dir);
411 			nilfs_mark_inode_dirty(new_dir);
412 		}
413 	}
414 
415 	/*
416 	 * Like most other Unix systems, set the ctime for inodes on a
417 	 * rename.
418 	 */
419 	old_inode->i_ctime = CURRENT_TIME;
420 
421 	nilfs_delete_entry(old_de, old_page);
422 
423 	if (dir_de) {
424 		nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
425 		drop_nlink(old_dir);
426 	}
427 	nilfs_mark_inode_dirty(old_dir);
428 	nilfs_mark_inode_dirty(old_inode);
429 
430 	err = nilfs_transaction_commit(old_dir->i_sb);
431 	return err;
432 
433 out_dir:
434 	if (dir_de) {
435 		kunmap(dir_page);
436 		page_cache_release(dir_page);
437 	}
438 out_old:
439 	kunmap(old_page);
440 	page_cache_release(old_page);
441 out:
442 	nilfs_transaction_abort(old_dir->i_sb);
443 	return err;
444 }
445 
446 /*
447  * Export operations
448  */
449 static struct dentry *nilfs_get_parent(struct dentry *child)
450 {
451 	unsigned long ino;
452 	struct inode *inode;
453 	struct qstr dotdot = QSTR_INIT("..", 2);
454 	struct nilfs_root *root;
455 
456 	ino = nilfs_inode_by_name(d_inode(child), &dotdot);
457 	if (!ino)
458 		return ERR_PTR(-ENOENT);
459 
460 	root = NILFS_I(d_inode(child))->i_root;
461 
462 	inode = nilfs_iget(d_inode(child)->i_sb, root, ino);
463 	if (IS_ERR(inode))
464 		return ERR_CAST(inode);
465 
466 	return d_obtain_alias(inode);
467 }
468 
469 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
470 				       u64 ino, u32 gen)
471 {
472 	struct nilfs_root *root;
473 	struct inode *inode;
474 
475 	if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
476 		return ERR_PTR(-ESTALE);
477 
478 	root = nilfs_lookup_root(sb->s_fs_info, cno);
479 	if (!root)
480 		return ERR_PTR(-ESTALE);
481 
482 	inode = nilfs_iget(sb, root, ino);
483 	nilfs_put_root(root);
484 
485 	if (IS_ERR(inode))
486 		return ERR_CAST(inode);
487 	if (gen && inode->i_generation != gen) {
488 		iput(inode);
489 		return ERR_PTR(-ESTALE);
490 	}
491 	return d_obtain_alias(inode);
492 }
493 
494 static struct dentry *nilfs_fh_to_dentry(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_NON_CONNECTABLE &&
500 	     fh_len != NILFS_FID_SIZE_CONNECTABLE) ||
501 	    (fh_type != FILEID_NILFS_WITH_PARENT &&
502 	     fh_type != FILEID_NILFS_WITHOUT_PARENT))
503 		return NULL;
504 
505 	return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
506 }
507 
508 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
509 					 int fh_len, int fh_type)
510 {
511 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
512 
513 	if (fh_len != NILFS_FID_SIZE_CONNECTABLE ||
514 	    fh_type != FILEID_NILFS_WITH_PARENT)
515 		return NULL;
516 
517 	return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
518 }
519 
520 static int nilfs_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
521 			   struct inode *parent)
522 {
523 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
524 	struct nilfs_root *root = NILFS_I(inode)->i_root;
525 	int type;
526 
527 	if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
528 		*lenp = NILFS_FID_SIZE_CONNECTABLE;
529 		return FILEID_INVALID;
530 	}
531 	if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
532 		*lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
533 		return FILEID_INVALID;
534 	}
535 
536 	fid->cno = root->cno;
537 	fid->ino = inode->i_ino;
538 	fid->gen = inode->i_generation;
539 
540 	if (parent) {
541 		fid->parent_ino = parent->i_ino;
542 		fid->parent_gen = parent->i_generation;
543 		type = FILEID_NILFS_WITH_PARENT;
544 		*lenp = NILFS_FID_SIZE_CONNECTABLE;
545 	} else {
546 		type = FILEID_NILFS_WITHOUT_PARENT;
547 		*lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
548 	}
549 
550 	return type;
551 }
552 
553 const struct inode_operations nilfs_dir_inode_operations = {
554 	.create		= nilfs_create,
555 	.lookup		= nilfs_lookup,
556 	.link		= nilfs_link,
557 	.unlink		= nilfs_unlink,
558 	.symlink	= nilfs_symlink,
559 	.mkdir		= nilfs_mkdir,
560 	.rmdir		= nilfs_rmdir,
561 	.mknod		= nilfs_mknod,
562 	.rename		= nilfs_rename,
563 	.setattr	= nilfs_setattr,
564 	.permission	= nilfs_permission,
565 	.fiemap		= nilfs_fiemap,
566 };
567 
568 const struct inode_operations nilfs_special_inode_operations = {
569 	.setattr	= nilfs_setattr,
570 	.permission	= nilfs_permission,
571 };
572 
573 const struct inode_operations nilfs_symlink_inode_operations = {
574 	.readlink	= generic_readlink,
575 	.follow_link	= page_follow_link_light,
576 	.put_link	= page_put_link,
577 	.permission     = nilfs_permission,
578 };
579 
580 const struct export_operations nilfs_export_ops = {
581 	.encode_fh = nilfs_encode_fh,
582 	.fh_to_dentry = nilfs_fh_to_dentry,
583 	.fh_to_parent = nilfs_fh_to_parent,
584 	.get_parent = nilfs_get_parent,
585 };
586