1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * NILFS pathname lookup operations.
4 *
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 *
7 * Modified for NILFS by Amagai Yoshiji and Ryusuke Konishi.
8 */
9/*
10 *  linux/fs/ext2/namei.c
11 *
12 * Copyright (C) 1992, 1993, 1994, 1995
13 * Remy Card (card@masi.ibp.fr)
14 * Laboratoire MASI - Institut Blaise Pascal
15 * Universite Pierre et Marie Curie (Paris VI)
16 *
17 *  from
18 *
19 *  linux/fs/minix/namei.c
20 *
21 *  Copyright (C) 1991, 1992  Linus Torvalds
22 *
23 *  Big-endian to little-endian byte-swapping/bitmaps by
24 *        David S. Miller (davem@caip.rutgers.edu), 1995
25 */
26
27#include <linux/pagemap.h>
28#include "nilfs.h"
29#include "export.h"
30
31#define NILFS_FID_SIZE_NON_CONNECTABLE \
32	(offsetof(struct nilfs_fid, parent_gen) / 4)
33#define NILFS_FID_SIZE_CONNECTABLE	(sizeof(struct nilfs_fid) / 4)
34
35static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
36{
37	int err = nilfs_add_link(dentry, inode);
38
39	if (!err) {
40		d_instantiate_new(dentry, inode);
41		return 0;
42	}
43	inode_dec_link_count(inode);
44	unlock_new_inode(inode);
45	iput(inode);
46	return err;
47}
48
49/*
50 * Methods themselves.
51 */
52
53static struct dentry *
54nilfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
55{
56	struct inode *inode;
57	ino_t ino;
58
59	if (dentry->d_name.len > NILFS_NAME_LEN)
60		return ERR_PTR(-ENAMETOOLONG);
61
62	ino = nilfs_inode_by_name(dir, &dentry->d_name);
63	inode = ino ? nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino) : NULL;
64	return d_splice_alias(inode, dentry);
65}
66
67/*
68 * By the time this is called, we already have created
69 * the directory cache entry for the new file, but it
70 * is so far negative - it has no inode.
71 *
72 * If the create succeeds, we fill in the inode information
73 * with d_instantiate().
74 */
75static int nilfs_create(struct mnt_idmap *idmap, struct inode *dir,
76			struct dentry *dentry, umode_t mode, bool excl)
77{
78	struct inode *inode;
79	struct nilfs_transaction_info ti;
80	int err;
81
82	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
83	if (err)
84		return err;
85	inode = nilfs_new_inode(dir, mode);
86	err = PTR_ERR(inode);
87	if (!IS_ERR(inode)) {
88		inode->i_op = &nilfs_file_inode_operations;
89		inode->i_fop = &nilfs_file_operations;
90		inode->i_mapping->a_ops = &nilfs_aops;
91		nilfs_mark_inode_dirty(inode);
92		err = nilfs_add_nondir(dentry, inode);
93	}
94	if (!err)
95		err = nilfs_transaction_commit(dir->i_sb);
96	else
97		nilfs_transaction_abort(dir->i_sb);
98
99	return err;
100}
101
102static int
103nilfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
104	    struct dentry *dentry, umode_t mode, dev_t rdev)
105{
106	struct inode *inode;
107	struct nilfs_transaction_info ti;
108	int err;
109
110	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
111	if (err)
112		return err;
113	inode = nilfs_new_inode(dir, mode);
114	err = PTR_ERR(inode);
115	if (!IS_ERR(inode)) {
116		init_special_inode(inode, inode->i_mode, rdev);
117		nilfs_mark_inode_dirty(inode);
118		err = nilfs_add_nondir(dentry, inode);
119	}
120	if (!err)
121		err = nilfs_transaction_commit(dir->i_sb);
122	else
123		nilfs_transaction_abort(dir->i_sb);
124
125	return err;
126}
127
128static int nilfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
129			 struct dentry *dentry, const char *symname)
130{
131	struct nilfs_transaction_info ti;
132	struct super_block *sb = dir->i_sb;
133	unsigned int l = strlen(symname) + 1;
134	struct inode *inode;
135	int err;
136
137	if (l > sb->s_blocksize)
138		return -ENAMETOOLONG;
139
140	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
141	if (err)
142		return err;
143
144	inode = nilfs_new_inode(dir, S_IFLNK | 0777);
145	err = PTR_ERR(inode);
146	if (IS_ERR(inode))
147		goto out;
148
149	/* slow symlink */
150	inode->i_op = &nilfs_symlink_inode_operations;
151	inode_nohighmem(inode);
152	inode->i_mapping->a_ops = &nilfs_aops;
153	err = page_symlink(inode, symname, l);
154	if (err)
155		goto out_fail;
156
157	/* mark_inode_dirty(inode); */
158	/* page_symlink() do this */
159
160	err = nilfs_add_nondir(dentry, inode);
161out:
162	if (!err)
163		err = nilfs_transaction_commit(dir->i_sb);
164	else
165		nilfs_transaction_abort(dir->i_sb);
166
167	return err;
168
169out_fail:
170	drop_nlink(inode);
171	nilfs_mark_inode_dirty(inode);
172	unlock_new_inode(inode);
173	iput(inode);
174	goto out;
175}
176
177static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
178		      struct dentry *dentry)
179{
180	struct inode *inode = d_inode(old_dentry);
181	struct nilfs_transaction_info ti;
182	int err;
183
184	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
185	if (err)
186		return err;
187
188	inode_set_ctime_current(inode);
189	inode_inc_link_count(inode);
190	ihold(inode);
191
192	err = nilfs_add_link(dentry, inode);
193	if (!err) {
194		d_instantiate(dentry, inode);
195		err = nilfs_transaction_commit(dir->i_sb);
196	} else {
197		inode_dec_link_count(inode);
198		iput(inode);
199		nilfs_transaction_abort(dir->i_sb);
200	}
201
202	return err;
203}
204
205static int nilfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
206		       struct dentry *dentry, umode_t mode)
207{
208	struct inode *inode;
209	struct nilfs_transaction_info ti;
210	int err;
211
212	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
213	if (err)
214		return err;
215
216	inc_nlink(dir);
217
218	inode = nilfs_new_inode(dir, S_IFDIR | mode);
219	err = PTR_ERR(inode);
220	if (IS_ERR(inode))
221		goto out_dir;
222
223	inode->i_op = &nilfs_dir_inode_operations;
224	inode->i_fop = &nilfs_dir_operations;
225	inode->i_mapping->a_ops = &nilfs_aops;
226
227	inc_nlink(inode);
228
229	err = nilfs_make_empty(inode, dir);
230	if (err)
231		goto out_fail;
232
233	err = nilfs_add_link(dentry, inode);
234	if (err)
235		goto out_fail;
236
237	nilfs_mark_inode_dirty(inode);
238	d_instantiate_new(dentry, inode);
239out:
240	if (!err)
241		err = nilfs_transaction_commit(dir->i_sb);
242	else
243		nilfs_transaction_abort(dir->i_sb);
244
245	return err;
246
247out_fail:
248	drop_nlink(inode);
249	drop_nlink(inode);
250	nilfs_mark_inode_dirty(inode);
251	unlock_new_inode(inode);
252	iput(inode);
253out_dir:
254	drop_nlink(dir);
255	nilfs_mark_inode_dirty(dir);
256	goto out;
257}
258
259static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
260{
261	struct inode *inode;
262	struct nilfs_dir_entry *de;
263	struct folio *folio;
264	int err;
265
266	err = -ENOENT;
267	de = nilfs_find_entry(dir, &dentry->d_name, &folio);
268	if (!de)
269		goto out;
270
271	inode = d_inode(dentry);
272	err = -EIO;
273	if (le64_to_cpu(de->inode) != inode->i_ino)
274		goto out;
275
276	if (!inode->i_nlink) {
277		nilfs_warn(inode->i_sb,
278			   "deleting nonexistent file (ino=%lu), %d",
279			   inode->i_ino, inode->i_nlink);
280		set_nlink(inode, 1);
281	}
282	err = nilfs_delete_entry(de, folio);
283	folio_release_kmap(folio, de);
284	if (err)
285		goto out;
286
287	inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
288	drop_nlink(inode);
289	err = 0;
290out:
291	return err;
292}
293
294static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
295{
296	struct nilfs_transaction_info ti;
297	int err;
298
299	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
300	if (err)
301		return err;
302
303	err = nilfs_do_unlink(dir, dentry);
304
305	if (!err) {
306		nilfs_mark_inode_dirty(dir);
307		nilfs_mark_inode_dirty(d_inode(dentry));
308		err = nilfs_transaction_commit(dir->i_sb);
309	} else
310		nilfs_transaction_abort(dir->i_sb);
311
312	return err;
313}
314
315static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
316{
317	struct inode *inode = d_inode(dentry);
318	struct nilfs_transaction_info ti;
319	int err;
320
321	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
322	if (err)
323		return err;
324
325	err = -ENOTEMPTY;
326	if (nilfs_empty_dir(inode)) {
327		err = nilfs_do_unlink(dir, dentry);
328		if (!err) {
329			inode->i_size = 0;
330			drop_nlink(inode);
331			nilfs_mark_inode_dirty(inode);
332			drop_nlink(dir);
333			nilfs_mark_inode_dirty(dir);
334		}
335	}
336	if (!err)
337		err = nilfs_transaction_commit(dir->i_sb);
338	else
339		nilfs_transaction_abort(dir->i_sb);
340
341	return err;
342}
343
344static int nilfs_rename(struct mnt_idmap *idmap,
345			struct inode *old_dir, struct dentry *old_dentry,
346			struct inode *new_dir, struct dentry *new_dentry,
347			unsigned int flags)
348{
349	struct inode *old_inode = d_inode(old_dentry);
350	struct inode *new_inode = d_inode(new_dentry);
351	struct folio *dir_folio = NULL;
352	struct nilfs_dir_entry *dir_de = NULL;
353	struct folio *old_folio;
354	struct nilfs_dir_entry *old_de;
355	struct nilfs_transaction_info ti;
356	int err;
357
358	if (flags & ~RENAME_NOREPLACE)
359		return -EINVAL;
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_folio);
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_folio);
373		if (!dir_de)
374			goto out_old;
375	}
376
377	if (new_inode) {
378		struct folio *new_folio;
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_folio);
387		if (!new_de)
388			goto out_dir;
389		nilfs_set_link(new_dir, new_de, new_folio, old_inode);
390		folio_release_kmap(new_folio, new_de);
391		nilfs_mark_inode_dirty(new_dir);
392		inode_set_ctime_current(new_inode);
393		if (dir_de)
394			drop_nlink(new_inode);
395		drop_nlink(new_inode);
396		nilfs_mark_inode_dirty(new_inode);
397	} else {
398		err = nilfs_add_link(new_dentry, old_inode);
399		if (err)
400			goto out_dir;
401		if (dir_de) {
402			inc_nlink(new_dir);
403			nilfs_mark_inode_dirty(new_dir);
404		}
405	}
406
407	/*
408	 * Like most other Unix systems, set the ctime for inodes on a
409	 * rename.
410	 */
411	inode_set_ctime_current(old_inode);
412
413	nilfs_delete_entry(old_de, old_folio);
414
415	if (dir_de) {
416		nilfs_set_link(old_inode, dir_de, dir_folio, new_dir);
417		folio_release_kmap(dir_folio, dir_de);
418		drop_nlink(old_dir);
419	}
420	folio_release_kmap(old_folio, old_de);
421
422	nilfs_mark_inode_dirty(old_dir);
423	nilfs_mark_inode_dirty(old_inode);
424
425	err = nilfs_transaction_commit(old_dir->i_sb);
426	return err;
427
428out_dir:
429	if (dir_de)
430		folio_release_kmap(dir_folio, dir_de);
431out_old:
432	folio_release_kmap(old_folio, old_de);
433out:
434	nilfs_transaction_abort(old_dir->i_sb);
435	return err;
436}
437
438/*
439 * Export operations
440 */
441static struct dentry *nilfs_get_parent(struct dentry *child)
442{
443	unsigned long ino;
444	struct nilfs_root *root;
445
446	ino = nilfs_inode_by_name(d_inode(child), &dotdot_name);
447	if (!ino)
448		return ERR_PTR(-ENOENT);
449
450	root = NILFS_I(d_inode(child))->i_root;
451
452	return d_obtain_alias(nilfs_iget(child->d_sb, root, ino));
453}
454
455static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
456				       u64 ino, u32 gen)
457{
458	struct nilfs_root *root;
459	struct inode *inode;
460
461	if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
462		return ERR_PTR(-ESTALE);
463
464	root = nilfs_lookup_root(sb->s_fs_info, cno);
465	if (!root)
466		return ERR_PTR(-ESTALE);
467
468	inode = nilfs_iget(sb, root, ino);
469	nilfs_put_root(root);
470
471	if (IS_ERR(inode))
472		return ERR_CAST(inode);
473	if (gen && inode->i_generation != gen) {
474		iput(inode);
475		return ERR_PTR(-ESTALE);
476	}
477	return d_obtain_alias(inode);
478}
479
480static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
481					 int fh_len, int fh_type)
482{
483	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
484
485	if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE ||
486	    (fh_type != FILEID_NILFS_WITH_PARENT &&
487	     fh_type != FILEID_NILFS_WITHOUT_PARENT))
488		return NULL;
489
490	return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
491}
492
493static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
494					 int fh_len, int fh_type)
495{
496	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
497
498	if (fh_len < NILFS_FID_SIZE_CONNECTABLE ||
499	    fh_type != FILEID_NILFS_WITH_PARENT)
500		return NULL;
501
502	return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
503}
504
505static int nilfs_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
506			   struct inode *parent)
507{
508	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
509	struct nilfs_root *root = NILFS_I(inode)->i_root;
510	int type;
511
512	if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
513		*lenp = NILFS_FID_SIZE_CONNECTABLE;
514		return FILEID_INVALID;
515	}
516	if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
517		*lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
518		return FILEID_INVALID;
519	}
520
521	fid->cno = root->cno;
522	fid->ino = inode->i_ino;
523	fid->gen = inode->i_generation;
524
525	if (parent) {
526		fid->parent_ino = parent->i_ino;
527		fid->parent_gen = parent->i_generation;
528		type = FILEID_NILFS_WITH_PARENT;
529		*lenp = NILFS_FID_SIZE_CONNECTABLE;
530	} else {
531		type = FILEID_NILFS_WITHOUT_PARENT;
532		*lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
533	}
534
535	return type;
536}
537
538const struct inode_operations nilfs_dir_inode_operations = {
539	.create		= nilfs_create,
540	.lookup		= nilfs_lookup,
541	.link		= nilfs_link,
542	.unlink		= nilfs_unlink,
543	.symlink	= nilfs_symlink,
544	.mkdir		= nilfs_mkdir,
545	.rmdir		= nilfs_rmdir,
546	.mknod		= nilfs_mknod,
547	.rename		= nilfs_rename,
548	.setattr	= nilfs_setattr,
549	.permission	= nilfs_permission,
550	.fiemap		= nilfs_fiemap,
551	.fileattr_get	= nilfs_fileattr_get,
552	.fileattr_set	= nilfs_fileattr_set,
553};
554
555const struct inode_operations nilfs_special_inode_operations = {
556	.setattr	= nilfs_setattr,
557	.permission	= nilfs_permission,
558};
559
560const struct inode_operations nilfs_symlink_inode_operations = {
561	.get_link	= page_get_link,
562	.permission     = nilfs_permission,
563};
564
565const struct export_operations nilfs_export_ops = {
566	.encode_fh = nilfs_encode_fh,
567	.fh_to_dentry = nilfs_fh_to_dentry,
568	.fh_to_parent = nilfs_fh_to_parent,
569	.get_parent = nilfs_get_parent,
570};
571