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 
nilfs_add_nondir(struct dentry * dentry,struct inode * inode)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 *
nilfs_lookup(struct inode * dir,struct dentry * dentry,struct nameidata * nd)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  */
nilfs_create(struct inode * dir,struct dentry * dentry,umode_t mode,struct nameidata * nd)87 static int nilfs_create(struct inode *dir, struct dentry *dentry, umode_t 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
nilfs_mknod(struct inode * dir,struct dentry * dentry,umode_t mode,dev_t rdev)115 nilfs_mknod(struct inode *dir, struct dentry *dentry, umode_t 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 
nilfs_symlink(struct inode * dir,struct dentry * dentry,const char * symname)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 
nilfs_link(struct dentry * old_dentry,struct inode * dir,struct dentry * dentry)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 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
197 	if (err)
198 		return err;
199 
200 	inode->i_ctime = CURRENT_TIME;
201 	inode_inc_link_count(inode);
202 	ihold(inode);
203 
204 	err = nilfs_add_nondir(dentry, inode);
205 	if (!err)
206 		err = nilfs_transaction_commit(dir->i_sb);
207 	else
208 		nilfs_transaction_abort(dir->i_sb);
209 
210 	return err;
211 }
212 
nilfs_mkdir(struct inode * dir,struct dentry * dentry,umode_t mode)213 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
214 {
215 	struct inode *inode;
216 	struct nilfs_transaction_info ti;
217 	int err;
218 
219 	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
220 	if (err)
221 		return err;
222 
223 	inc_nlink(dir);
224 
225 	inode = nilfs_new_inode(dir, S_IFDIR | mode);
226 	err = PTR_ERR(inode);
227 	if (IS_ERR(inode))
228 		goto out_dir;
229 
230 	inode->i_op = &nilfs_dir_inode_operations;
231 	inode->i_fop = &nilfs_dir_operations;
232 	inode->i_mapping->a_ops = &nilfs_aops;
233 
234 	inc_nlink(inode);
235 
236 	err = nilfs_make_empty(inode, dir);
237 	if (err)
238 		goto out_fail;
239 
240 	err = nilfs_add_link(dentry, inode);
241 	if (err)
242 		goto out_fail;
243 
244 	nilfs_mark_inode_dirty(inode);
245 	d_instantiate(dentry, inode);
246 out:
247 	if (!err)
248 		err = nilfs_transaction_commit(dir->i_sb);
249 	else
250 		nilfs_transaction_abort(dir->i_sb);
251 
252 	return err;
253 
254 out_fail:
255 	drop_nlink(inode);
256 	drop_nlink(inode);
257 	nilfs_mark_inode_dirty(inode);
258 	iput(inode);
259 out_dir:
260 	drop_nlink(dir);
261 	nilfs_mark_inode_dirty(dir);
262 	goto out;
263 }
264 
nilfs_do_unlink(struct inode * dir,struct dentry * dentry)265 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
266 {
267 	struct inode *inode;
268 	struct nilfs_dir_entry *de;
269 	struct page *page;
270 	int err;
271 
272 	err = -ENOENT;
273 	de = nilfs_find_entry(dir, &dentry->d_name, &page);
274 	if (!de)
275 		goto out;
276 
277 	inode = dentry->d_inode;
278 	err = -EIO;
279 	if (le64_to_cpu(de->inode) != inode->i_ino)
280 		goto out;
281 
282 	if (!inode->i_nlink) {
283 		nilfs_warning(inode->i_sb, __func__,
284 			      "deleting nonexistent file (%lu), %d\n",
285 			      inode->i_ino, inode->i_nlink);
286 		set_nlink(inode, 1);
287 	}
288 	err = nilfs_delete_entry(de, page);
289 	if (err)
290 		goto out;
291 
292 	inode->i_ctime = dir->i_ctime;
293 	drop_nlink(inode);
294 	err = 0;
295 out:
296 	return err;
297 }
298 
nilfs_unlink(struct inode * dir,struct dentry * dentry)299 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
300 {
301 	struct nilfs_transaction_info ti;
302 	int err;
303 
304 	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
305 	if (err)
306 		return err;
307 
308 	err = nilfs_do_unlink(dir, dentry);
309 
310 	if (!err) {
311 		nilfs_mark_inode_dirty(dir);
312 		nilfs_mark_inode_dirty(dentry->d_inode);
313 		err = nilfs_transaction_commit(dir->i_sb);
314 	} else
315 		nilfs_transaction_abort(dir->i_sb);
316 
317 	return err;
318 }
319 
nilfs_rmdir(struct inode * dir,struct dentry * dentry)320 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
321 {
322 	struct inode *inode = dentry->d_inode;
323 	struct nilfs_transaction_info ti;
324 	int err;
325 
326 	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
327 	if (err)
328 		return err;
329 
330 	err = -ENOTEMPTY;
331 	if (nilfs_empty_dir(inode)) {
332 		err = nilfs_do_unlink(dir, dentry);
333 		if (!err) {
334 			inode->i_size = 0;
335 			drop_nlink(inode);
336 			nilfs_mark_inode_dirty(inode);
337 			drop_nlink(dir);
338 			nilfs_mark_inode_dirty(dir);
339 		}
340 	}
341 	if (!err)
342 		err = nilfs_transaction_commit(dir->i_sb);
343 	else
344 		nilfs_transaction_abort(dir->i_sb);
345 
346 	return err;
347 }
348 
nilfs_rename(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry)349 static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
350 			struct inode *new_dir,	struct dentry *new_dentry)
351 {
352 	struct inode *old_inode = old_dentry->d_inode;
353 	struct inode *new_inode = new_dentry->d_inode;
354 	struct page *dir_page = NULL;
355 	struct nilfs_dir_entry *dir_de = NULL;
356 	struct page *old_page;
357 	struct nilfs_dir_entry *old_de;
358 	struct nilfs_transaction_info ti;
359 	int err;
360 
361 	err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
362 	if (unlikely(err))
363 		return err;
364 
365 	err = -ENOENT;
366 	old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_page);
367 	if (!old_de)
368 		goto out;
369 
370 	if (S_ISDIR(old_inode->i_mode)) {
371 		err = -EIO;
372 		dir_de = nilfs_dotdot(old_inode, &dir_page);
373 		if (!dir_de)
374 			goto out_old;
375 	}
376 
377 	if (new_inode) {
378 		struct page *new_page;
379 		struct nilfs_dir_entry *new_de;
380 
381 		err = -ENOTEMPTY;
382 		if (dir_de && !nilfs_empty_dir(new_inode))
383 			goto out_dir;
384 
385 		err = -ENOENT;
386 		new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, &new_page);
387 		if (!new_de)
388 			goto out_dir;
389 		nilfs_set_link(new_dir, new_de, new_page, old_inode);
390 		nilfs_mark_inode_dirty(new_dir);
391 		new_inode->i_ctime = CURRENT_TIME;
392 		if (dir_de)
393 			drop_nlink(new_inode);
394 		drop_nlink(new_inode);
395 		nilfs_mark_inode_dirty(new_inode);
396 	} else {
397 		err = nilfs_add_link(new_dentry, old_inode);
398 		if (err)
399 			goto out_dir;
400 		if (dir_de) {
401 			inc_nlink(new_dir);
402 			nilfs_mark_inode_dirty(new_dir);
403 		}
404 	}
405 
406 	/*
407 	 * Like most other Unix systems, set the ctime for inodes on a
408 	 * rename.
409 	 */
410 	old_inode->i_ctime = CURRENT_TIME;
411 
412 	nilfs_delete_entry(old_de, old_page);
413 
414 	if (dir_de) {
415 		nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
416 		drop_nlink(old_dir);
417 	}
418 	nilfs_mark_inode_dirty(old_dir);
419 	nilfs_mark_inode_dirty(old_inode);
420 
421 	err = nilfs_transaction_commit(old_dir->i_sb);
422 	return err;
423 
424 out_dir:
425 	if (dir_de) {
426 		kunmap(dir_page);
427 		page_cache_release(dir_page);
428 	}
429 out_old:
430 	kunmap(old_page);
431 	page_cache_release(old_page);
432 out:
433 	nilfs_transaction_abort(old_dir->i_sb);
434 	return err;
435 }
436 
437 /*
438  * Export operations
439  */
nilfs_get_parent(struct dentry * child)440 static struct dentry *nilfs_get_parent(struct dentry *child)
441 {
442 	unsigned long ino;
443 	struct inode *inode;
444 	struct qstr dotdot = {.name = "..", .len = 2};
445 	struct nilfs_root *root;
446 
447 	ino = nilfs_inode_by_name(child->d_inode, &dotdot);
448 	if (!ino)
449 		return ERR_PTR(-ENOENT);
450 
451 	root = NILFS_I(child->d_inode)->i_root;
452 
453 	inode = nilfs_iget(child->d_inode->i_sb, root, ino);
454 	if (IS_ERR(inode))
455 		return ERR_CAST(inode);
456 
457 	return d_obtain_alias(inode);
458 }
459 
nilfs_get_dentry(struct super_block * sb,u64 cno,u64 ino,u32 gen)460 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
461 				       u64 ino, u32 gen)
462 {
463 	struct nilfs_root *root;
464 	struct inode *inode;
465 
466 	if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
467 		return ERR_PTR(-ESTALE);
468 
469 	root = nilfs_lookup_root(sb->s_fs_info, cno);
470 	if (!root)
471 		return ERR_PTR(-ESTALE);
472 
473 	inode = nilfs_iget(sb, root, ino);
474 	nilfs_put_root(root);
475 
476 	if (IS_ERR(inode))
477 		return ERR_CAST(inode);
478 	if (gen && inode->i_generation != gen) {
479 		iput(inode);
480 		return ERR_PTR(-ESTALE);
481 	}
482 	return d_obtain_alias(inode);
483 }
484 
nilfs_fh_to_dentry(struct super_block * sb,struct fid * fh,int fh_len,int fh_type)485 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
486 					 int fh_len, int fh_type)
487 {
488 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
489 
490 	if ((fh_len != NILFS_FID_SIZE_NON_CONNECTABLE &&
491 	     fh_len != NILFS_FID_SIZE_CONNECTABLE) ||
492 	    (fh_type != FILEID_NILFS_WITH_PARENT &&
493 	     fh_type != FILEID_NILFS_WITHOUT_PARENT))
494 		return NULL;
495 
496 	return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
497 }
498 
nilfs_fh_to_parent(struct super_block * sb,struct fid * fh,int fh_len,int fh_type)499 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
500 					 int fh_len, int fh_type)
501 {
502 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
503 
504 	if (fh_len != NILFS_FID_SIZE_CONNECTABLE ||
505 	    fh_type != FILEID_NILFS_WITH_PARENT)
506 		return NULL;
507 
508 	return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
509 }
510 
nilfs_encode_fh(struct dentry * dentry,__u32 * fh,int * lenp,int connectable)511 static int nilfs_encode_fh(struct dentry *dentry, __u32 *fh, int *lenp,
512 			   int connectable)
513 {
514 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
515 	struct inode *inode = dentry->d_inode;
516 	struct nilfs_root *root = NILFS_I(inode)->i_root;
517 	int type;
518 
519 	if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE ||
520 	    (connectable && *lenp < NILFS_FID_SIZE_CONNECTABLE))
521 		return 255;
522 
523 	fid->cno = root->cno;
524 	fid->ino = inode->i_ino;
525 	fid->gen = inode->i_generation;
526 
527 	if (connectable && !S_ISDIR(inode->i_mode)) {
528 		struct inode *parent;
529 
530 		spin_lock(&dentry->d_lock);
531 		parent = dentry->d_parent->d_inode;
532 		fid->parent_ino = parent->i_ino;
533 		fid->parent_gen = parent->i_generation;
534 		spin_unlock(&dentry->d_lock);
535 
536 		type = FILEID_NILFS_WITH_PARENT;
537 		*lenp = NILFS_FID_SIZE_CONNECTABLE;
538 	} else {
539 		type = FILEID_NILFS_WITHOUT_PARENT;
540 		*lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
541 	}
542 
543 	return type;
544 }
545 
546 const struct inode_operations nilfs_dir_inode_operations = {
547 	.create		= nilfs_create,
548 	.lookup		= nilfs_lookup,
549 	.link		= nilfs_link,
550 	.unlink		= nilfs_unlink,
551 	.symlink	= nilfs_symlink,
552 	.mkdir		= nilfs_mkdir,
553 	.rmdir		= nilfs_rmdir,
554 	.mknod		= nilfs_mknod,
555 	.rename		= nilfs_rename,
556 	.setattr	= nilfs_setattr,
557 	.permission	= nilfs_permission,
558 	.fiemap		= nilfs_fiemap,
559 };
560 
561 const struct inode_operations nilfs_special_inode_operations = {
562 	.setattr	= nilfs_setattr,
563 	.permission	= nilfs_permission,
564 };
565 
566 const struct inode_operations nilfs_symlink_inode_operations = {
567 	.readlink	= generic_readlink,
568 	.follow_link	= page_follow_link_light,
569 	.put_link	= page_put_link,
570 	.permission     = nilfs_permission,
571 };
572 
573 const struct export_operations nilfs_export_ops = {
574 	.encode_fh = nilfs_encode_fh,
575 	.fh_to_dentry = nilfs_fh_to_dentry,
576 	.fh_to_parent = nilfs_fh_to_parent,
577 	.get_parent = nilfs_get_parent,
578 };
579