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
49static 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
67static struct dentry *
68nilfs_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 */
89static 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
116static int
117nilfs_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
144static 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);
176out:
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
184out_fail:
185	drop_nlink(inode);
186	nilfs_mark_inode_dirty(inode);
187	unlock_new_inode(inode);
188	iput(inode);
189	goto out;
190}
191
192static 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
220static 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);
254out:
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
262out_fail:
263	drop_nlink(inode);
264	drop_nlink(inode);
265	nilfs_mark_inode_dirty(inode);
266	unlock_new_inode(inode);
267	iput(inode);
268out_dir:
269	drop_nlink(dir);
270	nilfs_mark_inode_dirty(dir);
271	goto out;
272}
273
274static 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;
304out:
305	return err;
306}
307
308static 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
329static 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
358static 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
433out_dir:
434	if (dir_de) {
435		kunmap(dir_page);
436		page_cache_release(dir_page);
437	}
438out_old:
439	kunmap(old_page);
440	page_cache_release(old_page);
441out:
442	nilfs_transaction_abort(old_dir->i_sb);
443	return err;
444}
445
446/*
447 * Export operations
448 */
449static 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
469static 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
494static 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
508static 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
520static 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
553const 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
568const struct inode_operations nilfs_special_inode_operations = {
569	.setattr	= nilfs_setattr,
570	.permission	= nilfs_permission,
571};
572
573const 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
580const 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