namei.c

  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	int res;
 59
 60	if (dentry->d_name.len > NILFS_NAME_LEN)
 61		return ERR_PTR(-ENAMETOOLONG);
 62
 63	res = nilfs_inode_by_name(dir, &dentry->d_name, &ino);
 64	if (res) {
 65		if (res != -ENOENT)
 66			return ERR_PTR(res);
 67		inode = NULL;
 68	} else {
 69		inode = nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino);
 70		if (inode == ERR_PTR(-ESTALE)) {
 71			nilfs_error(dir->i_sb,
 72					"deleted inode referenced: %lu", ino);
 73			return ERR_PTR(-EIO);
 74		}
 75	}
 76
 77	return d_splice_alias(inode, dentry);
 78}
 79
 80/*
 81 * By the time this is called, we already have created
 82 * the directory cache entry for the new file, but it
 83 * is so far negative - it has no inode.
 84 *
 85 * If the create succeeds, we fill in the inode information
 86 * with d_instantiate().
 87 */
 88static int nilfs_create(struct mnt_idmap *idmap, struct inode *dir,
 89			struct dentry *dentry, umode_t mode, bool excl)
 90{
 91	struct inode *inode;
 92	struct nilfs_transaction_info ti;
 93	int err;
 94
 95	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 96	if (err)
 97		return err;
 98	inode = nilfs_new_inode(dir, mode);
 99	err = PTR_ERR(inode);
100	if (!IS_ERR(inode)) {
101		inode->i_op = &nilfs_file_inode_operations;
102		inode->i_fop = &nilfs_file_operations;
103		inode->i_mapping->a_ops = &nilfs_aops;
104		nilfs_mark_inode_dirty(inode);
105		err = nilfs_add_nondir(dentry, inode);
106	}
107	if (!err)
108		err = nilfs_transaction_commit(dir->i_sb);
109	else
110		nilfs_transaction_abort(dir->i_sb);
111
112	return err;
113}
114
115static int
116nilfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
117	    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	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
124	if (err)
125		return err;
126	inode = nilfs_new_inode(dir, mode);
127	err = PTR_ERR(inode);
128	if (!IS_ERR(inode)) {
129		init_special_inode(inode, inode->i_mode, rdev);
130		nilfs_mark_inode_dirty(inode);
131		err = nilfs_add_nondir(dentry, inode);
132	}
133	if (!err)
134		err = nilfs_transaction_commit(dir->i_sb);
135	else
136		nilfs_transaction_abort(dir->i_sb);
137
138	return err;
139}
140
141static int nilfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
142			 struct dentry *dentry, const char *symname)
143{
144	struct nilfs_transaction_info ti;
145	struct super_block *sb = dir->i_sb;
146	unsigned int l = strlen(symname) + 1;
147	struct inode *inode;
148	int err;
149
150	if (l > sb->s_blocksize)
151		return -ENAMETOOLONG;
152
153	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
154	if (err)
155		return err;
156
157	inode = nilfs_new_inode(dir, S_IFLNK | 0777);
158	err = PTR_ERR(inode);
159	if (IS_ERR(inode))
160		goto out;
161
162	/* slow symlink */
163	inode->i_op = &nilfs_symlink_inode_operations;
164	inode_nohighmem(inode);
165	mapping_set_gfp_mask(inode->i_mapping,
166			     mapping_gfp_constraint(inode->i_mapping,
167						    ~__GFP_FS));
168	inode->i_mapping->a_ops = &nilfs_aops;
169	err = page_symlink(inode, symname, l);
170	if (err)
171		goto out_fail;
172
173	/* mark_inode_dirty(inode); */
174	/* page_symlink() do this */
175
176	err = nilfs_add_nondir(dentry, inode);
177out:
178	if (!err)
179		err = nilfs_transaction_commit(dir->i_sb);
180	else
181		nilfs_transaction_abort(dir->i_sb);
182
183	return err;
184
185out_fail:
186	drop_nlink(inode);
187	nilfs_mark_inode_dirty(inode);
188	unlock_new_inode(inode);
189	iput(inode);
190	goto out;
191}
192
193static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
194		      struct dentry *dentry)
195{
196	struct inode *inode = d_inode(old_dentry);
197	struct nilfs_transaction_info ti;
198	int err;
199
200	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
201	if (err)
202		return err;
203
204	inode_set_ctime_current(inode);
205	inode_inc_link_count(inode);
206	ihold(inode);
207
208	err = nilfs_add_link(dentry, inode);
209	if (!err) {
210		d_instantiate(dentry, inode);
211		err = nilfs_transaction_commit(dir->i_sb);
212	} else {
213		inode_dec_link_count(inode);
214		iput(inode);
215		nilfs_transaction_abort(dir->i_sb);
216	}
217
218	return err;
219}
220
221static struct dentry *nilfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
222				  struct dentry *dentry, umode_t mode)
223{
224	struct inode *inode;
225	struct nilfs_transaction_info ti;
226	int err;
227
228	err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
229	if (err)
230		return ERR_PTR(err);
231
232	inc_nlink(dir);
233
234	inode = nilfs_new_inode(dir, S_IFDIR | mode);
235	err = PTR_ERR(inode);
236	if (IS_ERR(inode))
237		goto out_dir;
238
239	inode->i_op = &nilfs_dir_inode_operations;
240	inode->i_fop = &nilfs_dir_operations;
241	inode->i_mapping->a_ops = &nilfs_aops;
242
243	inc_nlink(inode);
244
245	err = nilfs_make_empty(inode, dir);
246	if (err)
247		goto out_fail;
248
249	err = nilfs_add_link(dentry, inode);
250	if (err)
251		goto out_fail;
252
253	nilfs_mark_inode_dirty(inode);
254	d_instantiate_new(dentry, inode);
255out:
256	if (!err)
257		err = nilfs_transaction_commit(dir->i_sb);
258	else
259		nilfs_transaction_abort(dir->i_sb);
260
261	return ERR_PTR(err);
262
263out_fail:
264	drop_nlink(inode);
265	drop_nlink(inode);
266	nilfs_mark_inode_dirty(inode);
267	unlock_new_inode(inode);
268	iput(inode);
269out_dir:
270	drop_nlink(dir);
271	nilfs_mark_inode_dirty(dir);
272	goto out;
273}
274
275static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
276{
277	struct inode *inode;
278	struct nilfs_dir_entry *de;
279	struct folio *folio;
280	int err;
281
282	de = nilfs_find_entry(dir, &dentry->d_name, &folio);
283	if (IS_ERR(de)) {
284		err = PTR_ERR(de);
285		goto out;
286	}
287
288	inode = d_inode(dentry);
289	err = -EIO;
290	if (le64_to_cpu(de->inode) != inode->i_ino)
291		goto out;
292
293	if (!inode->i_nlink) {
294		nilfs_warn(inode->i_sb,
295			   "deleting nonexistent file (ino=%lu), %d",
296			   inode->i_ino, inode->i_nlink);
297		set_nlink(inode, 1);
298	}
299	err = nilfs_delete_entry(de, folio);
300	folio_release_kmap(folio, de);
301	if (err)
302		goto out;
303
304	inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
305	drop_nlink(inode);
306	err = 0;
307out:
308	return err;
309}
310
311static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
312{
313	struct nilfs_transaction_info ti;
314	int err;
315
316	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
317	if (err)
318		return err;
319
320	err = nilfs_do_unlink(dir, dentry);
321
322	if (!err) {
323		nilfs_mark_inode_dirty(dir);
324		nilfs_mark_inode_dirty(d_inode(dentry));
325		err = nilfs_transaction_commit(dir->i_sb);
326	} else
327		nilfs_transaction_abort(dir->i_sb);
328
329	return err;
330}
331
332static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
333{
334	struct inode *inode = d_inode(dentry);
335	struct nilfs_transaction_info ti;
336	int err;
337
338	err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
339	if (err)
340		return err;
341
342	err = -ENOTEMPTY;
343	if (nilfs_empty_dir(inode)) {
344		err = nilfs_do_unlink(dir, dentry);
345		if (!err) {
346			inode->i_size = 0;
347			drop_nlink(inode);
348			nilfs_mark_inode_dirty(inode);
349			drop_nlink(dir);
350			nilfs_mark_inode_dirty(dir);
351		}
352	}
353	if (!err)
354		err = nilfs_transaction_commit(dir->i_sb);
355	else
356		nilfs_transaction_abort(dir->i_sb);
357
358	return err;
359}
360
361static int nilfs_rename(struct mnt_idmap *idmap,
362			struct inode *old_dir, struct dentry *old_dentry,
363			struct inode *new_dir, struct dentry *new_dentry,
364			unsigned int flags)
365{
366	struct inode *old_inode = d_inode(old_dentry);
367	struct inode *new_inode = d_inode(new_dentry);
368	struct folio *dir_folio = NULL;
369	struct nilfs_dir_entry *dir_de = NULL;
370	struct folio *old_folio;
371	struct nilfs_dir_entry *old_de;
372	struct nilfs_transaction_info ti;
373	bool old_is_dir = S_ISDIR(old_inode->i_mode);
374	int err;
375
376	if (flags & ~RENAME_NOREPLACE)
377		return -EINVAL;
378
379	err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
380	if (unlikely(err))
381		return err;
382
383	old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_folio);
384	if (IS_ERR(old_de)) {
385		err = PTR_ERR(old_de);
386		goto out;
387	}
388
389	if (old_is_dir && old_dir != new_dir) {
390		err = -EIO;
391		dir_de = nilfs_dotdot(old_inode, &dir_folio);
392		if (!dir_de)
393			goto out_old;
394	}
395
396	if (new_inode) {
397		struct folio *new_folio;
398		struct nilfs_dir_entry *new_de;
399
400		err = -ENOTEMPTY;
401		if (old_is_dir && !nilfs_empty_dir(new_inode))
402			goto out_dir;
403
404		new_de = nilfs_find_entry(new_dir, &new_dentry->d_name,
405					  &new_folio);
406		if (IS_ERR(new_de)) {
407			err = PTR_ERR(new_de);
408			goto out_dir;
409		}
410		err = nilfs_set_link(new_dir, new_de, new_folio, old_inode);
411		folio_release_kmap(new_folio, new_de);
412		if (unlikely(err))
413			goto out_dir;
414		nilfs_mark_inode_dirty(new_dir);
415		inode_set_ctime_current(new_inode);
416		if (old_is_dir)
417			drop_nlink(new_inode);
418		drop_nlink(new_inode);
419		nilfs_mark_inode_dirty(new_inode);
420	} else {
421		err = nilfs_add_link(new_dentry, old_inode);
422		if (err)
423			goto out_dir;
424		if (old_is_dir) {
425			inc_nlink(new_dir);
426			nilfs_mark_inode_dirty(new_dir);
427		}
428	}
429
430	/*
431	 * Like most other Unix systems, set the ctime for inodes on a
432	 * rename.
433	 */
434	inode_set_ctime_current(old_inode);
435
436	err = nilfs_delete_entry(old_de, old_folio);
437	if (likely(!err)) {
438		if (old_is_dir) {
439			if (old_dir != new_dir)
440				err = nilfs_set_link(old_inode, dir_de,
441						     dir_folio, new_dir);
442			drop_nlink(old_dir);
443		}
444		nilfs_mark_inode_dirty(old_dir);
445	}
446	nilfs_mark_inode_dirty(old_inode);
447
448out_dir:
449	if (dir_de)
450		folio_release_kmap(dir_folio, dir_de);
451out_old:
452	folio_release_kmap(old_folio, old_de);
453out:
454	if (likely(!err))
455		err = nilfs_transaction_commit(old_dir->i_sb);
456	else
457		nilfs_transaction_abort(old_dir->i_sb);
458	return err;
459}
460
461/*
462 * Export operations
463 */
464static struct dentry *nilfs_get_parent(struct dentry *child)
465{
466	ino_t ino;
467	int res;
468	struct nilfs_root *root;
469
470	res = nilfs_inode_by_name(d_inode(child), &dotdot_name, &ino);
471	if (res)
472		return ERR_PTR(res);
473
474	root = NILFS_I(d_inode(child))->i_root;
475
476	return d_obtain_alias(nilfs_iget(child->d_sb, root, ino));
477}
478
479static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
480				       u64 ino, u32 gen)
481{
482	struct nilfs_root *root;
483	struct inode *inode;
484
485	if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
486		return ERR_PTR(-ESTALE);
487
488	root = nilfs_lookup_root(sb->s_fs_info, cno);
489	if (!root)
490		return ERR_PTR(-ESTALE);
491
492	inode = nilfs_iget(sb, root, ino);
493	nilfs_put_root(root);
494
495	if (IS_ERR(inode))
496		return ERR_CAST(inode);
497	if (gen && inode->i_generation != gen) {
498		iput(inode);
499		return ERR_PTR(-ESTALE);
500	}
501	return d_obtain_alias(inode);
502}
503
504static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
505					 int fh_len, int fh_type)
506{
507	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
508
509	if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE ||
510	    (fh_type != FILEID_NILFS_WITH_PARENT &&
511	     fh_type != FILEID_NILFS_WITHOUT_PARENT))
512		return NULL;
513
514	return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
515}
516
517static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
518					 int fh_len, int fh_type)
519{
520	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
521
522	if (fh_len < NILFS_FID_SIZE_CONNECTABLE ||
523	    fh_type != FILEID_NILFS_WITH_PARENT)
524		return NULL;
525
526	return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
527}
528
529static int nilfs_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
530			   struct inode *parent)
531{
532	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
533	struct nilfs_root *root = NILFS_I(inode)->i_root;
534	int type;
535
536	if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
537		*lenp = NILFS_FID_SIZE_CONNECTABLE;
538		return FILEID_INVALID;
539	}
540	if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
541		*lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
542		return FILEID_INVALID;
543	}
544
545	fid->cno = root->cno;
546	fid->ino = inode->i_ino;
547	fid->gen = inode->i_generation;
548
549	if (parent) {
550		fid->parent_ino = parent->i_ino;
551		fid->parent_gen = parent->i_generation;
552		type = FILEID_NILFS_WITH_PARENT;
553		*lenp = NILFS_FID_SIZE_CONNECTABLE;
554	} else {
555		type = FILEID_NILFS_WITHOUT_PARENT;
556		*lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
557	}
558
559	return type;
560}
561
562const struct inode_operations nilfs_dir_inode_operations = {
563	.create		= nilfs_create,
564	.lookup		= nilfs_lookup,
565	.link		= nilfs_link,
566	.unlink		= nilfs_unlink,
567	.symlink	= nilfs_symlink,
568	.mkdir		= nilfs_mkdir,
569	.rmdir		= nilfs_rmdir,
570	.mknod		= nilfs_mknod,
571	.rename		= nilfs_rename,
572	.setattr	= nilfs_setattr,
573	.permission	= nilfs_permission,
574	.fiemap		= nilfs_fiemap,
575	.fileattr_get	= nilfs_fileattr_get,
576	.fileattr_set	= nilfs_fileattr_set,
577};
578
579const struct inode_operations nilfs_special_inode_operations = {
580	.setattr	= nilfs_setattr,
581	.permission	= nilfs_permission,
582};
583
584const struct inode_operations nilfs_symlink_inode_operations = {
585	.get_link	= page_get_link,
586	.permission     = nilfs_permission,
587};
588
589const struct export_operations nilfs_export_ops = {
590	.encode_fh = nilfs_encode_fh,
591	.fh_to_dentry = nilfs_fh_to_dentry,
592	.fh_to_parent = nilfs_fh_to_parent,
593	.get_parent = nilfs_get_parent,
594};