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

source code of linux/fs/ufs/dir.c