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