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 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(inode: dir);
51 block_write_end(NULL, mapping, pos, len, len, page, NULL);
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 unlock_page(page);
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
69static inline void ufs_put_page(struct page *page)
70{
71 kunmap(page);
72 put_page(page);
73}
74
75ino_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(sbp: dir->i_sb, n: de->d_ino);
84 ufs_put_page(page);
85 }
86 return res;
87}
88
89
90/* Releases the page */
91void 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(sbp: dir->i_sb, n: 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(sbp: dir->i_sb, n: inode->i_ino);
105 ufs_set_de_type(sb: dir->i_sb, de, mode: 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(inode: dir, ts: inode_set_ctime_current(inode: dir));
111 mark_inode_dirty(inode: dir);
112 ufs_handle_dirsync(dir);
113}
114
115
116static 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(sbp: sb, n: 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(sbp: sb, n: 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;
152out:
153 SetPageChecked(page);
154 return true;
155
156 /* Too bad, we had an error */
157
158Ebadsize:
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;
164Eshort:
165 error = "rec_len is smaller than minimal";
166 goto bad_entry;
167Ealign:
168 error = "unaligned directory entry";
169 goto bad_entry;
170Enamelen:
171 error = "rec_len is too small for name_len";
172 goto bad_entry;
173Espan:
174 error = "directory entry across blocks";
175 goto bad_entry;
176Einumber:
177 error = "inode out of bounds";
178bad_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, de: p));
183 goto fail;
184Eend:
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);
190fail:
191 SetPageError(page);
192 return false;
193}
194
195static struct page *ufs_get_page(struct inode *dir, unsigned long n)
196{
197 struct address_space *mapping = dir->i_mapping;
198 struct page *page = read_mapping_page(mapping, index: n, NULL);
199 if (!IS_ERR(ptr: page)) {
200 kmap(page);
201 if (unlikely(!PageChecked(page))) {
202 if (!ufs_check_page(page))
203 goto fail;
204 }
205 }
206 return page;
207
208fail:
209 ufs_put_page(page);
210 return ERR_PTR(error: -EIO);
211}
212
213/*
214 * Return the offset into page `page_nr' of the last valid
215 * byte in that page, plus one.
216 */
217static unsigned
218ufs_last_byte(struct inode *inode, unsigned long page_nr)
219{
220 unsigned last_byte = inode->i_size;
221
222 last_byte -= page_nr << PAGE_SHIFT;
223 if (last_byte > PAGE_SIZE)
224 last_byte = PAGE_SIZE;
225 return last_byte;
226}
227
228static inline struct ufs_dir_entry *
229ufs_next_entry(struct super_block *sb, struct ufs_dir_entry *p)
230{
231 return (struct ufs_dir_entry *)((char *)p +
232 fs16_to_cpu(sbp: sb, n: p->d_reclen));
233}
234
235struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct page **p)
236{
237 struct page *page = ufs_get_page(dir, n: 0);
238 struct ufs_dir_entry *de = NULL;
239
240 if (!IS_ERR(ptr: page)) {
241 de = ufs_next_entry(sb: dir->i_sb,
242 p: (struct ufs_dir_entry *)page_address(page));
243 *p = page;
244 }
245 return de;
246}
247
248/*
249 * ufs_find_entry()
250 *
251 * finds an entry in the specified directory with the wanted name. It
252 * returns the page in which the entry was found, and the entry itself
253 * (as a parameter - res_dir). Page is returned mapped and unlocked.
254 * Entry is guaranteed to be valid.
255 */
256struct ufs_dir_entry *ufs_find_entry(struct inode *dir, const struct qstr *qstr,
257 struct page **res_page)
258{
259 struct super_block *sb = dir->i_sb;
260 const unsigned char *name = qstr->name;
261 int namelen = qstr->len;
262 unsigned reclen = UFS_DIR_REC_LEN(namelen);
263 unsigned long start, n;
264 unsigned long npages = dir_pages(inode: dir);
265 struct page *page = NULL;
266 struct ufs_inode_info *ui = UFS_I(inode: dir);
267 struct ufs_dir_entry *de;
268
269 UFSD("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen);
270
271 if (npages == 0 || namelen > UFS_MAXNAMLEN)
272 goto out;
273
274 /* OFFSET_CACHE */
275 *res_page = NULL;
276
277 start = ui->i_dir_start_lookup;
278
279 if (start >= npages)
280 start = 0;
281 n = start;
282 do {
283 char *kaddr;
284 page = ufs_get_page(dir, n);
285 if (!IS_ERR(ptr: page)) {
286 kaddr = page_address(page);
287 de = (struct ufs_dir_entry *) kaddr;
288 kaddr += ufs_last_byte(inode: dir, page_nr: n) - reclen;
289 while ((char *) de <= kaddr) {
290 if (ufs_match(sb, len: namelen, name, de))
291 goto found;
292 de = ufs_next_entry(sb, p: de);
293 }
294 ufs_put_page(page);
295 }
296 if (++n >= npages)
297 n = 0;
298 } while (n != start);
299out:
300 return NULL;
301
302found:
303 *res_page = page;
304 ui->i_dir_start_lookup = n;
305 return de;
306}
307
308/*
309 * Parent is locked.
310 */
311int ufs_add_link(struct dentry *dentry, struct inode *inode)
312{
313 struct inode *dir = d_inode(dentry: dentry->d_parent);
314 const unsigned char *name = dentry->d_name.name;
315 int namelen = dentry->d_name.len;
316 struct super_block *sb = dir->i_sb;
317 unsigned reclen = UFS_DIR_REC_LEN(namelen);
318 const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize;
319 unsigned short rec_len, name_len;
320 struct page *page = NULL;
321 struct ufs_dir_entry *de;
322 unsigned long npages = dir_pages(inode: dir);
323 unsigned long n;
324 char *kaddr;
325 loff_t pos;
326 int err;
327
328 UFSD("ENTER, name %s, namelen %u\n", name, namelen);
329
330 /*
331 * We take care of directory expansion in the same loop.
332 * This code plays outside i_size, so it locks the page
333 * to protect that region.
334 */
335 for (n = 0; n <= npages; n++) {
336 char *dir_end;
337
338 page = ufs_get_page(dir, n);
339 err = PTR_ERR(ptr: page);
340 if (IS_ERR(ptr: page))
341 goto out;
342 lock_page(page);
343 kaddr = page_address(page);
344 dir_end = kaddr + ufs_last_byte(inode: dir, page_nr: n);
345 de = (struct ufs_dir_entry *)kaddr;
346 kaddr += PAGE_SIZE - reclen;
347 while ((char *)de <= kaddr) {
348 if ((char *)de == dir_end) {
349 /* We hit i_size */
350 name_len = 0;
351 rec_len = chunk_size;
352 de->d_reclen = cpu_to_fs16(sbp: sb, n: chunk_size);
353 de->d_ino = 0;
354 goto got_it;
355 }
356 if (de->d_reclen == 0) {
357 ufs_error(dir->i_sb, __func__,
358 "zero-length directory entry");
359 err = -EIO;
360 goto out_unlock;
361 }
362 err = -EEXIST;
363 if (ufs_match(sb, len: namelen, name, de))
364 goto out_unlock;
365 name_len = UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de));
366 rec_len = fs16_to_cpu(sbp: sb, n: de->d_reclen);
367 if (!de->d_ino && rec_len >= reclen)
368 goto got_it;
369 if (rec_len >= name_len + reclen)
370 goto got_it;
371 de = (struct ufs_dir_entry *) ((char *) de + rec_len);
372 }
373 unlock_page(page);
374 ufs_put_page(page);
375 }
376 BUG();
377 return -EINVAL;
378
379got_it:
380 pos = page_offset(page) +
381 (char*)de - (char*)page_address(page);
382 err = ufs_prepare_chunk(page, pos, len: rec_len);
383 if (err)
384 goto out_unlock;
385 if (de->d_ino) {
386 struct ufs_dir_entry *de1 =
387 (struct ufs_dir_entry *) ((char *) de + name_len);
388 de1->d_reclen = cpu_to_fs16(sbp: sb, n: rec_len - name_len);
389 de->d_reclen = cpu_to_fs16(sbp: sb, n: name_len);
390
391 de = de1;
392 }
393
394 ufs_set_de_namlen(sb, de, value: namelen);
395 memcpy(de->d_name, name, namelen + 1);
396 de->d_ino = cpu_to_fs32(sbp: sb, n: inode->i_ino);
397 ufs_set_de_type(sb, de, mode: inode->i_mode);
398
399 ufs_commit_chunk(page, pos, len: rec_len);
400 inode_set_mtime_to_ts(inode: dir, ts: inode_set_ctime_current(inode: dir));
401
402 mark_inode_dirty(inode: dir);
403 err = ufs_handle_dirsync(dir);
404 /* OFFSET_CACHE */
405out_put:
406 ufs_put_page(page);
407out:
408 return err;
409out_unlock:
410 unlock_page(page);
411 goto out_put;
412}
413
414static inline unsigned
415ufs_validate_entry(struct super_block *sb, char *base,
416 unsigned offset, unsigned mask)
417{
418 struct ufs_dir_entry *de = (struct ufs_dir_entry*)(base + offset);
419 struct ufs_dir_entry *p = (struct ufs_dir_entry*)(base + (offset&mask));
420 while ((char*)p < (char*)de)
421 p = ufs_next_entry(sb, p);
422 return (char *)p - base;
423}
424
425
426/*
427 * This is blatantly stolen from ext2fs
428 */
429static int
430ufs_readdir(struct file *file, struct dir_context *ctx)
431{
432 loff_t pos = ctx->pos;
433 struct inode *inode = file_inode(f: file);
434 struct super_block *sb = inode->i_sb;
435 unsigned int offset = pos & ~PAGE_MASK;
436 unsigned long n = pos >> PAGE_SHIFT;
437 unsigned long npages = dir_pages(inode);
438 unsigned chunk_mask = ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
439 bool need_revalidate = !inode_eq_iversion(inode, old: file->f_version);
440 unsigned flags = UFS_SB(sb)->s_flags;
441
442 UFSD("BEGIN\n");
443
444 if (pos > inode->i_size - UFS_DIR_REC_LEN(1))
445 return 0;
446
447 for ( ; n < npages; n++, offset = 0) {
448 char *kaddr, *limit;
449 struct ufs_dir_entry *de;
450
451 struct page *page = ufs_get_page(dir: inode, n);
452
453 if (IS_ERR(ptr: page)) {
454 ufs_error(sb, __func__,
455 "bad page in #%lu",
456 inode->i_ino);
457 ctx->pos += PAGE_SIZE - offset;
458 return -EIO;
459 }
460 kaddr = page_address(page);
461 if (unlikely(need_revalidate)) {
462 if (offset) {
463 offset = ufs_validate_entry(sb, base: kaddr, offset, mask: chunk_mask);
464 ctx->pos = (n<<PAGE_SHIFT) + offset;
465 }
466 file->f_version = inode_query_iversion(inode);
467 need_revalidate = false;
468 }
469 de = (struct ufs_dir_entry *)(kaddr+offset);
470 limit = kaddr + ufs_last_byte(inode, page_nr: n) - UFS_DIR_REC_LEN(1);
471 for ( ;(char*)de <= limit; de = ufs_next_entry(sb, p: de)) {
472 if (de->d_ino) {
473 unsigned char d_type = DT_UNKNOWN;
474
475 UFSD("filldir(%s,%u)\n", de->d_name,
476 fs32_to_cpu(sb, de->d_ino));
477 UFSD("namlen %u\n", ufs_get_de_namlen(sb, de));
478
479 if ((flags & UFS_DE_MASK) == UFS_DE_44BSD)
480 d_type = de->d_u.d_44.d_type;
481
482 if (!dir_emit(ctx, name: de->d_name,
483 namelen: ufs_get_de_namlen(sb, de),
484 ino: fs32_to_cpu(sbp: sb, n: de->d_ino),
485 type: d_type)) {
486 ufs_put_page(page);
487 return 0;
488 }
489 }
490 ctx->pos += fs16_to_cpu(sbp: sb, n: de->d_reclen);
491 }
492 ufs_put_page(page);
493 }
494 return 0;
495}
496
497
498/*
499 * ufs_delete_entry deletes a directory entry by merging it with the
500 * previous entry.
501 */
502int ufs_delete_entry(struct inode *inode, struct ufs_dir_entry *dir,
503 struct page * page)
504{
505 struct super_block *sb = inode->i_sb;
506 char *kaddr = page_address(page);
507 unsigned from = ((char*)dir - kaddr) & ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
508 unsigned to = ((char*)dir - kaddr) + fs16_to_cpu(sbp: sb, n: dir->d_reclen);
509 loff_t pos;
510 struct ufs_dir_entry *pde = NULL;
511 struct ufs_dir_entry *de = (struct ufs_dir_entry *) (kaddr + from);
512 int err;
513
514 UFSD("ENTER\n");
515
516 UFSD("ino %u, reclen %u, namlen %u, name %s\n",
517 fs32_to_cpu(sb, de->d_ino),
518 fs16_to_cpu(sb, de->d_reclen),
519 ufs_get_de_namlen(sb, de), de->d_name);
520
521 while ((char*)de < (char*)dir) {
522 if (de->d_reclen == 0) {
523 ufs_error(inode->i_sb, __func__,
524 "zero-length directory entry");
525 err = -EIO;
526 goto out;
527 }
528 pde = de;
529 de = ufs_next_entry(sb, p: de);
530 }
531 if (pde)
532 from = (char*)pde - (char*)page_address(page);
533
534 pos = page_offset(page) + from;
535 lock_page(page);
536 err = ufs_prepare_chunk(page, pos, len: to - from);
537 BUG_ON(err);
538 if (pde)
539 pde->d_reclen = cpu_to_fs16(sbp: sb, n: to - from);
540 dir->d_ino = 0;
541 ufs_commit_chunk(page, pos, len: to - from);
542 inode_set_mtime_to_ts(inode, ts: inode_set_ctime_current(inode));
543 mark_inode_dirty(inode);
544 err = ufs_handle_dirsync(dir: inode);
545out:
546 ufs_put_page(page);
547 UFSD("EXIT\n");
548 return err;
549}
550
551int ufs_make_empty(struct inode * inode, struct inode *dir)
552{
553 struct super_block * sb = dir->i_sb;
554 struct address_space *mapping = inode->i_mapping;
555 struct page *page = grab_cache_page(mapping, index: 0);
556 const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize;
557 struct ufs_dir_entry * de;
558 char *base;
559 int err;
560
561 if (!page)
562 return -ENOMEM;
563
564 err = ufs_prepare_chunk(page, pos: 0, len: chunk_size);
565 if (err) {
566 unlock_page(page);
567 goto fail;
568 }
569
570 kmap(page);
571 base = (char*)page_address(page);
572 memset(base, 0, PAGE_SIZE);
573
574 de = (struct ufs_dir_entry *) base;
575
576 de->d_ino = cpu_to_fs32(sbp: sb, n: inode->i_ino);
577 ufs_set_de_type(sb, de, mode: inode->i_mode);
578 ufs_set_de_namlen(sb, de, value: 1);
579 de->d_reclen = cpu_to_fs16(sbp: sb, UFS_DIR_REC_LEN(1));
580 strcpy (p: de->d_name, q: ".");
581 de = (struct ufs_dir_entry *)
582 ((char *)de + fs16_to_cpu(sbp: sb, n: de->d_reclen));
583 de->d_ino = cpu_to_fs32(sbp: sb, n: dir->i_ino);
584 ufs_set_de_type(sb, de, mode: dir->i_mode);
585 de->d_reclen = cpu_to_fs16(sbp: sb, n: chunk_size - UFS_DIR_REC_LEN(1));
586 ufs_set_de_namlen(sb, de, value: 2);
587 strcpy (p: de->d_name, q: "..");
588 kunmap(page);
589
590 ufs_commit_chunk(page, pos: 0, len: chunk_size);
591 err = ufs_handle_dirsync(dir: inode);
592fail:
593 put_page(page);
594 return err;
595}
596
597/*
598 * routine to check that the specified directory is empty (for rmdir)
599 */
600int ufs_empty_dir(struct inode * inode)
601{
602 struct super_block *sb = inode->i_sb;
603 struct page *page = NULL;
604 unsigned long i, npages = dir_pages(inode);
605
606 for (i = 0; i < npages; i++) {
607 char *kaddr;
608 struct ufs_dir_entry *de;
609 page = ufs_get_page(dir: inode, n: i);
610
611 if (IS_ERR(ptr: page))
612 continue;
613
614 kaddr = page_address(page);
615 de = (struct ufs_dir_entry *)kaddr;
616 kaddr += ufs_last_byte(inode, page_nr: i) - UFS_DIR_REC_LEN(1);
617
618 while ((char *)de <= kaddr) {
619 if (de->d_reclen == 0) {
620 ufs_error(inode->i_sb, __func__,
621 "zero-length directory entry: "
622 "kaddr=%p, de=%p\n", kaddr, de);
623 goto not_empty;
624 }
625 if (de->d_ino) {
626 u16 namelen=ufs_get_de_namlen(sb, de);
627 /* check for . and .. */
628 if (de->d_name[0] != '.')
629 goto not_empty;
630 if (namelen > 2)
631 goto not_empty;
632 if (namelen < 2) {
633 if (inode->i_ino !=
634 fs32_to_cpu(sbp: sb, n: de->d_ino))
635 goto not_empty;
636 } else if (de->d_name[1] != '.')
637 goto not_empty;
638 }
639 de = ufs_next_entry(sb, p: de);
640 }
641 ufs_put_page(page);
642 }
643 return 1;
644
645not_empty:
646 ufs_put_page(page);
647 return 0;
648}
649
650const struct file_operations ufs_dir_operations = {
651 .read = generic_read_dir,
652 .iterate_shared = ufs_readdir,
653 .fsync = generic_file_fsync,
654 .llseek = generic_file_llseek,
655};
656

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