xref: /linux/fs/ufs/dir.c (revision 3352633ce6b221d64bf40644d412d9670e7d56e3)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/ufs/ufs_dir.c
4  *
5  * Copyright (C) 1996
6  * Adrian Rodriguez (adrian@franklins-tower.rutgers.edu)
7  * Laboratory for Computer Science Research Computing Facility
8  * Rutgers, The State University of New Jersey
9  *
10  * swab support by Francois-Rene Rideau <fare@tunes.org> 19970406
11  *
12  * 4.4BSD (FreeBSD) support added on February 1st 1998 by
13  * Niels Kristian Bech Jensen <nkbj@image.dk> partially based
14  * on code by Martin von Loewis <martin@mira.isdn.cs.tu-berlin.de>.
15  *
16  * Migration to usage of "page cache" on May 2006 by
17  * Evgeniy Dushistov <dushistov@mail.ru> based on ext2 code base.
18  */
19 
20 #include <linux/time.h>
21 #include <linux/fs.h>
22 #include <linux/swap.h>
23 #include <linux/iversion.h>
24 
25 #include "ufs_fs.h"
26 #include "ufs.h"
27 #include "swab.h"
28 #include "util.h"
29 
30 /*
31  * NOTE! unlike strncmp, ufs_match returns 1 for success, 0 for failure.
32  *
33  * len <= UFS_MAXNAMLEN and de != NULL are guaranteed by caller.
34  */
ufs_match(struct super_block * sb,int len,const unsigned char * name,struct ufs_dir_entry * de)35 static inline int ufs_match(struct super_block *sb, int len,
36 		const unsigned char *name, struct ufs_dir_entry *de)
37 {
38 	if (len != ufs_get_de_namlen(sb, de))
39 		return 0;
40 	if (!de->d_ino)
41 		return 0;
42 	return !memcmp(name, de->d_name, len);
43 }
44 
ufs_commit_chunk(struct folio * folio,loff_t pos,unsigned len)45 static void ufs_commit_chunk(struct folio *folio, loff_t pos, unsigned len)
46 {
47 	struct address_space *mapping = folio->mapping;
48 	struct inode *dir = mapping->host;
49 
50 	inode_inc_iversion(dir);
51 	block_write_end(NULL, mapping, pos, len, len, folio, NULL);
52 	if (pos+len > dir->i_size) {
53 		i_size_write(dir, pos+len);
54 		mark_inode_dirty(dir);
55 	}
56 	folio_unlock(folio);
57 }
58 
ufs_handle_dirsync(struct inode * dir)59 static int ufs_handle_dirsync(struct inode *dir)
60 {
61 	int err;
62 
63 	err = filemap_write_and_wait(dir->i_mapping);
64 	if (!err)
65 		err = sync_inode_metadata(dir, 1);
66 	return err;
67 }
68 
ufs_inode_by_name(struct inode * dir,const struct qstr * qstr)69 ino_t ufs_inode_by_name(struct inode *dir, const struct qstr *qstr)
70 {
71 	ino_t res = 0;
72 	struct ufs_dir_entry *de;
73 	struct folio *folio;
74 
75 	de = ufs_find_entry(dir, qstr, &folio);
76 	if (de) {
77 		res = fs32_to_cpu(dir->i_sb, de->d_ino);
78 		folio_release_kmap(folio, de);
79 	}
80 	return res;
81 }
82 
83 
84 /* Releases the page */
ufs_set_link(struct inode * dir,struct ufs_dir_entry * de,struct folio * folio,struct inode * inode,bool update_times)85 void ufs_set_link(struct inode *dir, struct ufs_dir_entry *de,
86 		  struct folio *folio, struct inode *inode,
87 		  bool update_times)
88 {
89 	loff_t pos = folio_pos(folio) + offset_in_folio(folio, de);
90 	unsigned len = fs16_to_cpu(dir->i_sb, de->d_reclen);
91 	int err;
92 
93 	folio_lock(folio);
94 	err = ufs_prepare_chunk(folio, pos, len);
95 	BUG_ON(err);
96 
97 	de->d_ino = cpu_to_fs32(dir->i_sb, inode->i_ino);
98 	ufs_set_de_type(dir->i_sb, de, inode->i_mode);
99 
100 	ufs_commit_chunk(folio, pos, len);
101 	folio_release_kmap(folio, de);
102 	if (update_times)
103 		inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
104 	mark_inode_dirty(dir);
105 	ufs_handle_dirsync(dir);
106 }
107 
ufs_check_folio(struct folio * folio,char * kaddr)108 static bool ufs_check_folio(struct folio *folio, char *kaddr)
109 {
110 	struct inode *dir = folio->mapping->host;
111 	struct super_block *sb = dir->i_sb;
112 	unsigned offs, rec_len;
113 	unsigned limit = folio_size(folio);
114 	const unsigned chunk_mask = UFS_SB(sb)->s_uspi->s_dirblksize - 1;
115 	struct ufs_dir_entry *p;
116 	char *error;
117 
118 	if (dir->i_size < folio_pos(folio) + limit) {
119 		limit = offset_in_folio(folio, dir->i_size);
120 		if (limit & chunk_mask)
121 			goto Ebadsize;
122 		if (!limit)
123 			goto out;
124 	}
125 	for (offs = 0; offs <= limit - UFS_DIR_REC_LEN(1); offs += rec_len) {
126 		p = (struct ufs_dir_entry *)(kaddr + offs);
127 		rec_len = fs16_to_cpu(sb, p->d_reclen);
128 
129 		if (rec_len < UFS_DIR_REC_LEN(1))
130 			goto Eshort;
131 		if (rec_len & 3)
132 			goto Ealign;
133 		if (rec_len < UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, p)))
134 			goto Enamelen;
135 		if (((offs + rec_len - 1) ^ offs) & ~chunk_mask)
136 			goto Espan;
137 		if (fs32_to_cpu(sb, p->d_ino) > (UFS_SB(sb)->s_uspi->s_ipg *
138 						  UFS_SB(sb)->s_uspi->s_ncg))
139 			goto Einumber;
140 	}
141 	if (offs != limit)
142 		goto Eend;
143 out:
144 	folio_set_checked(folio);
145 	return true;
146 
147 	/* Too bad, we had an error */
148 
149 Ebadsize:
150 	ufs_error(sb, __func__,
151 		  "size of directory #%lu is not a multiple of chunk size",
152 		  dir->i_ino
153 	);
154 	goto fail;
155 Eshort:
156 	error = "rec_len is smaller than minimal";
157 	goto bad_entry;
158 Ealign:
159 	error = "unaligned directory entry";
160 	goto bad_entry;
161 Enamelen:
162 	error = "rec_len is too small for name_len";
163 	goto bad_entry;
164 Espan:
165 	error = "directory entry across blocks";
166 	goto bad_entry;
167 Einumber:
168 	error = "inode out of bounds";
169 bad_entry:
170 	ufs_error(sb, __func__, "bad entry in directory #%lu: %s - "
171 		   "offset=%llu, rec_len=%d, name_len=%d",
172 		   dir->i_ino, error, folio_pos(folio) + offs,
173 		   rec_len, ufs_get_de_namlen(sb, p));
174 	goto fail;
175 Eend:
176 	p = (struct ufs_dir_entry *)(kaddr + offs);
177 	ufs_error(sb, __func__,
178 		   "entry in directory #%lu spans the page boundary"
179 		   "offset=%llu",
180 		   dir->i_ino, folio_pos(folio) + offs);
181 fail:
182 	return false;
183 }
184 
ufs_get_folio(struct inode * dir,unsigned long n,struct folio ** foliop)185 static void *ufs_get_folio(struct inode *dir, unsigned long n,
186 		struct folio **foliop)
187 {
188 	struct address_space *mapping = dir->i_mapping;
189 	struct folio *folio = read_mapping_folio(mapping, n, NULL);
190 	void *kaddr;
191 
192 	if (IS_ERR(folio))
193 		return ERR_CAST(folio);
194 	kaddr = kmap_local_folio(folio, 0);
195 	if (unlikely(!folio_test_checked(folio))) {
196 		if (!ufs_check_folio(folio, kaddr))
197 			goto fail;
198 	}
199 	*foliop = folio;
200 	return kaddr;
201 
202 fail:
203 	folio_release_kmap(folio, kaddr);
204 	return ERR_PTR(-EIO);
205 }
206 
207 /*
208  * Return the offset into page `page_nr' of the last valid
209  * byte in that page, plus one.
210  */
211 static unsigned
ufs_last_byte(struct inode * inode,unsigned long page_nr)212 ufs_last_byte(struct inode *inode, unsigned long page_nr)
213 {
214 	unsigned last_byte = inode->i_size;
215 
216 	last_byte -= page_nr << PAGE_SHIFT;
217 	if (last_byte > PAGE_SIZE)
218 		last_byte = PAGE_SIZE;
219 	return last_byte;
220 }
221 
222 static inline struct ufs_dir_entry *
ufs_next_entry(struct super_block * sb,struct ufs_dir_entry * p)223 ufs_next_entry(struct super_block *sb, struct ufs_dir_entry *p)
224 {
225 	return (struct ufs_dir_entry *)((char *)p +
226 					fs16_to_cpu(sb, p->d_reclen));
227 }
228 
ufs_dotdot(struct inode * dir,struct folio ** foliop)229 struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct folio **foliop)
230 {
231 	struct ufs_dir_entry *de = ufs_get_folio(dir, 0, foliop);
232 
233 	if (!IS_ERR(de))
234 		return ufs_next_entry(dir->i_sb, de);
235 
236 	return NULL;
237 }
238 
239 /*
240  *	ufs_find_entry()
241  *
242  * finds an entry in the specified directory with the wanted name. It
243  * returns the page in which the entry was found, and the entry itself
244  * (as a parameter - res_dir). Page is returned mapped and unlocked.
245  * Entry is guaranteed to be valid.
246  */
ufs_find_entry(struct inode * dir,const struct qstr * qstr,struct folio ** foliop)247 struct ufs_dir_entry *ufs_find_entry(struct inode *dir, const struct qstr *qstr,
248 				     struct folio **foliop)
249 {
250 	struct super_block *sb = dir->i_sb;
251 	const unsigned char *name = qstr->name;
252 	int namelen = qstr->len;
253 	unsigned reclen = UFS_DIR_REC_LEN(namelen);
254 	unsigned long start, n;
255 	unsigned long npages = dir_pages(dir);
256 	struct ufs_inode_info *ui = UFS_I(dir);
257 	struct ufs_dir_entry *de;
258 
259 	UFSD("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen);
260 
261 	if (npages == 0 || namelen > UFS_MAXNAMLEN)
262 		goto out;
263 
264 	start = ui->i_dir_start_lookup;
265 
266 	if (start >= npages)
267 		start = 0;
268 	n = start;
269 	do {
270 		char *kaddr = ufs_get_folio(dir, n, foliop);
271 
272 		if (!IS_ERR(kaddr)) {
273 			de = (struct ufs_dir_entry *)kaddr;
274 			kaddr += ufs_last_byte(dir, n) - reclen;
275 			while ((char *) de <= kaddr) {
276 				if (ufs_match(sb, namelen, name, de))
277 					goto found;
278 				de = ufs_next_entry(sb, de);
279 			}
280 			folio_release_kmap(*foliop, kaddr);
281 		}
282 		if (++n >= npages)
283 			n = 0;
284 	} while (n != start);
285 out:
286 	return NULL;
287 
288 found:
289 	ui->i_dir_start_lookup = n;
290 	return de;
291 }
292 
293 /*
294  *	Parent is locked.
295  */
ufs_add_link(struct dentry * dentry,struct inode * inode)296 int ufs_add_link(struct dentry *dentry, struct inode *inode)
297 {
298 	struct inode *dir = d_inode(dentry->d_parent);
299 	const unsigned char *name = dentry->d_name.name;
300 	int namelen = dentry->d_name.len;
301 	struct super_block *sb = dir->i_sb;
302 	unsigned reclen = UFS_DIR_REC_LEN(namelen);
303 	const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize;
304 	unsigned short rec_len, name_len;
305 	struct folio *folio = NULL;
306 	struct ufs_dir_entry *de;
307 	unsigned long npages = dir_pages(dir);
308 	unsigned long n;
309 	loff_t pos;
310 	int err;
311 
312 	UFSD("ENTER, name %s, namelen %u\n", name, namelen);
313 
314 	/*
315 	 * We take care of directory expansion in the same loop.
316 	 * This code plays outside i_size, so it locks the folio
317 	 * to protect that region.
318 	 */
319 	for (n = 0; n <= npages; n++) {
320 		char *kaddr = ufs_get_folio(dir, n, &folio);
321 		char *dir_end;
322 
323 		if (IS_ERR(kaddr))
324 			return PTR_ERR(kaddr);
325 		folio_lock(folio);
326 		dir_end = kaddr + ufs_last_byte(dir, n);
327 		de = (struct ufs_dir_entry *)kaddr;
328 		kaddr += folio_size(folio) - reclen;
329 		while ((char *)de <= kaddr) {
330 			if ((char *)de == dir_end) {
331 				/* We hit i_size */
332 				name_len = 0;
333 				rec_len = chunk_size;
334 				de->d_reclen = cpu_to_fs16(sb, chunk_size);
335 				de->d_ino = 0;
336 				goto got_it;
337 			}
338 			if (de->d_reclen == 0) {
339 				ufs_error(dir->i_sb, __func__,
340 					  "zero-length directory entry");
341 				err = -EIO;
342 				goto out_unlock;
343 			}
344 			err = -EEXIST;
345 			if (ufs_match(sb, namelen, name, de))
346 				goto out_unlock;
347 			name_len = UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de));
348 			rec_len = fs16_to_cpu(sb, de->d_reclen);
349 			if (!de->d_ino && rec_len >= reclen)
350 				goto got_it;
351 			if (rec_len >= name_len + reclen)
352 				goto got_it;
353 			de = (struct ufs_dir_entry *) ((char *) de + rec_len);
354 		}
355 		folio_unlock(folio);
356 		folio_release_kmap(folio, kaddr);
357 	}
358 	BUG();
359 	return -EINVAL;
360 
361 got_it:
362 	pos = folio_pos(folio) + offset_in_folio(folio, de);
363 	err = ufs_prepare_chunk(folio, pos, rec_len);
364 	if (err)
365 		goto out_unlock;
366 	if (de->d_ino) {
367 		struct ufs_dir_entry *de1 =
368 			(struct ufs_dir_entry *) ((char *) de + name_len);
369 		de1->d_reclen = cpu_to_fs16(sb, rec_len - name_len);
370 		de->d_reclen = cpu_to_fs16(sb, name_len);
371 
372 		de = de1;
373 	}
374 
375 	ufs_set_de_namlen(sb, de, namelen);
376 	memcpy(de->d_name, name, namelen + 1);
377 	de->d_ino = cpu_to_fs32(sb, inode->i_ino);
378 	ufs_set_de_type(sb, de, inode->i_mode);
379 
380 	ufs_commit_chunk(folio, pos, rec_len);
381 	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
382 
383 	mark_inode_dirty(dir);
384 	err = ufs_handle_dirsync(dir);
385 	/* OFFSET_CACHE */
386 out_put:
387 	folio_release_kmap(folio, de);
388 	return err;
389 out_unlock:
390 	folio_unlock(folio);
391 	goto out_put;
392 }
393 
394 static inline unsigned
ufs_validate_entry(struct super_block * sb,char * base,unsigned offset,unsigned mask)395 ufs_validate_entry(struct super_block *sb, char *base,
396 		   unsigned offset, unsigned mask)
397 {
398 	struct ufs_dir_entry *de = (struct ufs_dir_entry*)(base + offset);
399 	struct ufs_dir_entry *p = (struct ufs_dir_entry*)(base + (offset&mask));
400 	while ((char*)p < (char*)de)
401 		p = ufs_next_entry(sb, p);
402 	return (char *)p - base;
403 }
404 
405 
406 /*
407  * This is blatantly stolen from ext2fs
408  */
409 static int
ufs_readdir(struct file * file,struct dir_context * ctx)410 ufs_readdir(struct file *file, struct dir_context *ctx)
411 {
412 	loff_t pos = ctx->pos;
413 	struct inode *inode = file_inode(file);
414 	struct super_block *sb = inode->i_sb;
415 	unsigned int offset = pos & ~PAGE_MASK;
416 	unsigned long n = pos >> PAGE_SHIFT;
417 	unsigned long npages = dir_pages(inode);
418 	unsigned chunk_mask = ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
419 	bool need_revalidate = !inode_eq_iversion(inode, *(u64 *)file->private_data);
420 	unsigned flags = UFS_SB(sb)->s_flags;
421 
422 	UFSD("BEGIN\n");
423 
424 	if (pos > inode->i_size - UFS_DIR_REC_LEN(1))
425 		return 0;
426 
427 	for ( ; n < npages; n++, offset = 0) {
428 		struct ufs_dir_entry *de;
429 		struct folio *folio;
430 		char *kaddr = ufs_get_folio(inode, n, &folio);
431 		char *limit;
432 
433 		if (IS_ERR(kaddr)) {
434 			ufs_error(sb, __func__,
435 				  "bad page in #%lu",
436 				  inode->i_ino);
437 			ctx->pos += PAGE_SIZE - offset;
438 			return PTR_ERR(kaddr);
439 		}
440 		if (unlikely(need_revalidate)) {
441 			if (offset) {
442 				offset = ufs_validate_entry(sb, kaddr, offset, chunk_mask);
443 				ctx->pos = (n<<PAGE_SHIFT) + offset;
444 			}
445 			*(u64 *)file->private_data = inode_query_iversion(inode);
446 			need_revalidate = false;
447 		}
448 		de = (struct ufs_dir_entry *)(kaddr+offset);
449 		limit = kaddr + ufs_last_byte(inode, n) - UFS_DIR_REC_LEN(1);
450 		for ( ;(char*)de <= limit; de = ufs_next_entry(sb, de)) {
451 			if (de->d_ino) {
452 				unsigned char d_type = DT_UNKNOWN;
453 
454 				UFSD("filldir(%s,%u)\n", de->d_name,
455 				      fs32_to_cpu(sb, de->d_ino));
456 				UFSD("namlen %u\n", ufs_get_de_namlen(sb, de));
457 
458 				if ((flags & UFS_DE_MASK) == UFS_DE_44BSD)
459 					d_type = de->d_u.d_44.d_type;
460 
461 				if (!dir_emit(ctx, de->d_name,
462 					       ufs_get_de_namlen(sb, de),
463 					       fs32_to_cpu(sb, de->d_ino),
464 					       d_type)) {
465 					folio_release_kmap(folio, de);
466 					return 0;
467 				}
468 			}
469 			ctx->pos += fs16_to_cpu(sb, de->d_reclen);
470 		}
471 		folio_release_kmap(folio, kaddr);
472 	}
473 	return 0;
474 }
475 
476 
477 /*
478  * ufs_delete_entry deletes a directory entry by merging it with the
479  * previous entry.
480  */
ufs_delete_entry(struct inode * inode,struct ufs_dir_entry * dir,struct folio * folio)481 int ufs_delete_entry(struct inode *inode, struct ufs_dir_entry *dir,
482 		     struct folio *folio)
483 {
484 	struct super_block *sb = inode->i_sb;
485 	size_t from, to;
486 	char *kaddr;
487 	loff_t pos;
488 	struct ufs_dir_entry *de, *pde = NULL;
489 	int err;
490 
491 	UFSD("ENTER\n");
492 
493 	from = offset_in_folio(folio, dir);
494 	to = from + fs16_to_cpu(sb, dir->d_reclen);
495 	kaddr = (char *)dir - from;
496 	from &= ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
497 	de = (struct ufs_dir_entry *) (kaddr + from);
498 
499 	UFSD("ino %u, reclen %u, namlen %u, name %s\n",
500 	      fs32_to_cpu(sb, de->d_ino),
501 	      fs16_to_cpu(sb, de->d_reclen),
502 	      ufs_get_de_namlen(sb, de), de->d_name);
503 
504 	while ((char*)de < (char*)dir) {
505 		if (de->d_reclen == 0) {
506 			ufs_error(inode->i_sb, __func__,
507 				  "zero-length directory entry");
508 			err = -EIO;
509 			goto out;
510 		}
511 		pde = de;
512 		de = ufs_next_entry(sb, de);
513 	}
514 	if (pde)
515 		from = offset_in_folio(folio, pde);
516 	pos = folio_pos(folio) + from;
517 	folio_lock(folio);
518 	err = ufs_prepare_chunk(folio, pos, to - from);
519 	BUG_ON(err);
520 	if (pde)
521 		pde->d_reclen = cpu_to_fs16(sb, to - from);
522 	dir->d_ino = 0;
523 	ufs_commit_chunk(folio, pos, to - from);
524 	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
525 	mark_inode_dirty(inode);
526 	err = ufs_handle_dirsync(inode);
527 out:
528 	folio_release_kmap(folio, kaddr);
529 	UFSD("EXIT\n");
530 	return err;
531 }
532 
ufs_make_empty(struct inode * inode,struct inode * dir)533 int ufs_make_empty(struct inode * inode, struct inode *dir)
534 {
535 	struct super_block * sb = dir->i_sb;
536 	struct address_space *mapping = inode->i_mapping;
537 	struct folio *folio = filemap_grab_folio(mapping, 0);
538 	const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize;
539 	struct ufs_dir_entry * de;
540 	int err;
541 	char *kaddr;
542 
543 	if (IS_ERR(folio))
544 		return PTR_ERR(folio);
545 
546 	err = ufs_prepare_chunk(folio, 0, chunk_size);
547 	if (err) {
548 		folio_unlock(folio);
549 		goto fail;
550 	}
551 
552 	kaddr = kmap_local_folio(folio, 0);
553 	memset(kaddr, 0, folio_size(folio));
554 
555 	de = (struct ufs_dir_entry *)kaddr;
556 
557 	de->d_ino = cpu_to_fs32(sb, inode->i_ino);
558 	ufs_set_de_type(sb, de, inode->i_mode);
559 	ufs_set_de_namlen(sb, de, 1);
560 	de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1));
561 	strcpy (de->d_name, ".");
562 	de = (struct ufs_dir_entry *)
563 		((char *)de + fs16_to_cpu(sb, de->d_reclen));
564 	de->d_ino = cpu_to_fs32(sb, dir->i_ino);
565 	ufs_set_de_type(sb, de, dir->i_mode);
566 	de->d_reclen = cpu_to_fs16(sb, chunk_size - UFS_DIR_REC_LEN(1));
567 	ufs_set_de_namlen(sb, de, 2);
568 	strcpy (de->d_name, "..");
569 	kunmap_local(kaddr);
570 
571 	ufs_commit_chunk(folio, 0, chunk_size);
572 	err = ufs_handle_dirsync(inode);
573 fail:
574 	folio_put(folio);
575 	return err;
576 }
577 
578 /*
579  * routine to check that the specified directory is empty (for rmdir)
580  */
ufs_empty_dir(struct inode * inode)581 int ufs_empty_dir(struct inode * inode)
582 {
583 	struct super_block *sb = inode->i_sb;
584 	struct folio *folio;
585 	char *kaddr;
586 	unsigned long i, npages = dir_pages(inode);
587 
588 	for (i = 0; i < npages; i++) {
589 		struct ufs_dir_entry *de;
590 
591 		kaddr = ufs_get_folio(inode, i, &folio);
592 		if (IS_ERR(kaddr))
593 			continue;
594 
595 		de = (struct ufs_dir_entry *)kaddr;
596 		kaddr += ufs_last_byte(inode, i) - UFS_DIR_REC_LEN(1);
597 
598 		while ((char *)de <= kaddr) {
599 			if (de->d_reclen == 0) {
600 				ufs_error(inode->i_sb, __func__,
601 					"zero-length directory entry: "
602 					"kaddr=%p, de=%p\n", kaddr, de);
603 				goto not_empty;
604 			}
605 			if (de->d_ino) {
606 				u16 namelen=ufs_get_de_namlen(sb, de);
607 				/* check for . and .. */
608 				if (de->d_name[0] != '.')
609 					goto not_empty;
610 				if (namelen > 2)
611 					goto not_empty;
612 				if (namelen < 2) {
613 					if (inode->i_ino !=
614 					    fs32_to_cpu(sb, de->d_ino))
615 						goto not_empty;
616 				} else if (de->d_name[1] != '.')
617 					goto not_empty;
618 			}
619 			de = ufs_next_entry(sb, de);
620 		}
621 		folio_release_kmap(folio, kaddr);
622 	}
623 	return 1;
624 
625 not_empty:
626 	folio_release_kmap(folio, kaddr);
627 	return 0;
628 }
629 
ufs_dir_open(struct inode * inode,struct file * file)630 static int ufs_dir_open(struct inode *inode, struct file *file)
631 {
632 	file->private_data = kzalloc(sizeof(u64), GFP_KERNEL);
633 	if (!file->private_data)
634 		return -ENOMEM;
635 	return 0;
636 }
637 
ufs_dir_release(struct inode * inode,struct file * file)638 static int ufs_dir_release(struct inode *inode, struct file *file)
639 {
640 	kfree(file->private_data);
641 	return 0;
642 }
643 
ufs_dir_llseek(struct file * file,loff_t offset,int whence)644 static loff_t ufs_dir_llseek(struct file *file, loff_t offset, int whence)
645 {
646 	return generic_llseek_cookie(file, offset, whence,
647 				     (u64 *)file->private_data);
648 }
649 
650 const struct file_operations ufs_dir_operations = {
651 	.open		= ufs_dir_open,
652 	.release	= ufs_dir_release,
653 	.read		= generic_read_dir,
654 	.iterate_shared	= ufs_readdir,
655 	.fsync		= generic_file_fsync,
656 	.llseek		= ufs_dir_llseek,
657 };
658