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