1 /*
2 * linux/fs/ufs/ufs_dir.c
3 *
4 * Copyright (C) 1996
5 * Adrian Rodriguez (adrian@franklins-tower.rutgers.edu)
6 * Laboratory for Computer Science Research Computing Facility
7 * Rutgers, The State University of New Jersey
8 *
9 * swab support by Francois-Rene Rideau <fare@tunes.org> 19970406
10 *
11 * 4.4BSD (FreeBSD) support added on February 1st 1998 by
12 * Niels Kristian Bech Jensen <nkbj@image.dk> partially based
13 * on code by Martin von Loewis <martin@mira.isdn.cs.tu-berlin.de>.
14 *
15 * Migration to usage of "page cache" on May 2006 by
16 * Evgeniy Dushistov <dushistov@mail.ru> based on ext2 code base.
17 */
18
19 #include <linux/time.h>
20 #include <linux/fs.h>
21 #include <linux/swap.h>
22
23 #include "ufs_fs.h"
24 #include "ufs.h"
25 #include "swab.h"
26 #include "util.h"
27
28 /*
29 * NOTE! unlike strncmp, ufs_match returns 1 for success, 0 for failure.
30 *
31 * len <= UFS_MAXNAMLEN and de != NULL are guaranteed by caller.
32 */
33 static inline int ufs_match(struct super_block *sb, int len,
34 const char * const name, struct ufs_dir_entry * de)
35 {
36 if (len != ufs_get_de_namlen(sb, de))
37 return 0;
38 if (!de->d_ino)
39 return 0;
40 return !memcmp(name, de->d_name, len);
41 }
42
43 static int ufs_commit_chunk(struct page *page, loff_t pos, unsigned len)
44 {
45 struct address_space *mapping = page->mapping;
46 struct inode *dir = mapping->host;
47 int err = 0;
48
49 dir->i_version++;
50 block_write_end(NULL, mapping, pos, len, len, page, NULL);
51 if (pos+len > dir->i_size) {
52 i_size_write(dir, pos+len);
53 mark_inode_dirty(dir);
54 }
55 if (IS_DIRSYNC(dir))
56 err = write_one_page(page, 1);
57 else
58 unlock_page(page);
59 return err;
60 }
61
62 static inline void ufs_put_page(struct page *page)
63 {
64 kunmap(page);
65 page_cache_release(page);
66 }
67
68 static inline unsigned long ufs_dir_pages(struct inode *inode)
69 {
70 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
71 }
72
73 ino_t ufs_inode_by_name(struct inode *dir, struct dentry *dentry)
74 {
75 ino_t res = 0;
76 struct ufs_dir_entry *de;
77 struct page *page;
78
79 de = ufs_find_entry(dir, dentry, &page);
80 if (de) {
81 res = fs32_to_cpu(dir->i_sb, de->d_ino);
82 ufs_put_page(page);
83 }
84 return res;
85 }
86
87
88 /* Releases the page */
89 void ufs_set_link(struct inode *dir, struct ufs_dir_entry *de,
90 struct page *page, struct inode *inode)
91 {
92 loff_t pos = page_offset(page) +
93 (char *) de - (char *) page_address(page);
94 unsigned len = fs16_to_cpu(dir->i_sb, de->d_reclen);
95 int err;
96
97 lock_page(page);
98 err = __ufs_write_begin(NULL, page->mapping, pos, len,
99 AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
100 BUG_ON(err);
101
102 de->d_ino = cpu_to_fs32(dir->i_sb, inode->i_ino);
103 ufs_set_de_type(dir->i_sb, de, inode->i_mode);
104
105 err = ufs_commit_chunk(page, pos, len);
106 ufs_put_page(page);
107 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
108 mark_inode_dirty(dir);
109 }
110
111
112 static void ufs_check_page(struct page *page)
113 {
114 struct inode *dir = page->mapping->host;
115 struct super_block *sb = dir->i_sb;
116 char *kaddr = page_address(page);
117 unsigned offs, rec_len;
118 unsigned limit = PAGE_CACHE_SIZE;
119 const unsigned chunk_mask = UFS_SB(sb)->s_uspi->s_dirblksize - 1;
120 struct ufs_dir_entry *p;
121 char *error;
122
123 if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
124 limit = dir->i_size & ~PAGE_CACHE_MASK;
125 if (limit & chunk_mask)
126 goto Ebadsize;
127 if (!limit)
128 goto out;
129 }
130 for (offs = 0; offs <= limit - UFS_DIR_REC_LEN(1); offs += rec_len) {
131 p = (struct ufs_dir_entry *)(kaddr + offs);
132 rec_len = fs16_to_cpu(sb, p->d_reclen);
133
134 if (rec_len < UFS_DIR_REC_LEN(1))
135 goto Eshort;
136 if (rec_len & 3)
137 goto Ealign;
138 if (rec_len < UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, p)))
139 goto Enamelen;
140 if (((offs + rec_len - 1) ^ offs) & ~chunk_mask)
141 goto Espan;
142 if (fs32_to_cpu(sb, p->d_ino) > (UFS_SB(sb)->s_uspi->s_ipg *
143 UFS_SB(sb)->s_uspi->s_ncg))
144 goto Einumber;
145 }
146 if (offs != limit)
147 goto Eend;
148 out:
149 SetPageChecked(page);
150 return;
151
152 /* Too bad, we had an error */
153
154 Ebadsize:
155 ufs_error(sb, "ufs_check_page",
156 "size of directory #%lu is not a multiple of chunk size",
157 dir->i_ino
158 );
159 goto fail;
160 Eshort:
161 error = "rec_len is smaller than minimal";
162 goto bad_entry;
163 Ealign:
164 error = "unaligned directory entry";
165 goto bad_entry;
166 Enamelen:
167 error = "rec_len is too small for name_len";
168 goto bad_entry;
169 Espan:
170 error = "directory entry across blocks";
171 goto bad_entry;
172 Einumber:
173 error = "inode out of bounds";
174 bad_entry:
175 ufs_error (sb, "ufs_check_page", "bad entry in directory #%lu: %s - "
176 "offset=%lu, rec_len=%d, name_len=%d",
177 dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
178 rec_len, ufs_get_de_namlen(sb, p));
179 goto fail;
180 Eend:
181 p = (struct ufs_dir_entry *)(kaddr + offs);
182 ufs_error(sb, __FUNCTION__,
183 "entry in directory #%lu spans the page boundary"
184 "offset=%lu",
185 dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs);
186 fail:
187 SetPageChecked(page);
188 SetPageError(page);
189 }
190
191 static struct page *ufs_get_page(struct inode *dir, unsigned long n)
192 {
193 struct address_space *mapping = dir->i_mapping;
194 struct page *page = read_mapping_page(mapping, n, NULL);
195 if (!IS_ERR(page)) {
196 kmap(page);
197 if (!PageChecked(page))
198 ufs_check_page(page);
199 if (PageError(page))
200 goto fail;
201 }
202 return page;
203
204 fail:
205 ufs_put_page(page);
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 */
213 static unsigned
214 ufs_last_byte(struct inode *inode, unsigned long page_nr)
215 {
216 unsigned last_byte = inode->i_size;
217
218 last_byte -= page_nr << PAGE_CACHE_SHIFT;
219 if (last_byte > PAGE_CACHE_SIZE)
220 last_byte = PAGE_CACHE_SIZE;
221 return last_byte;
222 }
223
224 static inline struct ufs_dir_entry *
225 ufs_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
231 struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct page **p)
232 {
233 struct page *page = ufs_get_page(dir, 0);
234 struct ufs_dir_entry *de = NULL;
235
236 if (!IS_ERR(page)) {
237 de = ufs_next_entry(dir->i_sb,
238 (struct ufs_dir_entry *)page_address(page));
239 *p = page;
240 }
241 return de;
242 }
243
244 /*
245 * ufs_find_entry()
246 *
247 * finds an entry in the specified directory with the wanted name. It
248 * returns the page in which the entry was found, and the entry itself
249 * (as a parameter - res_dir). Page is returned mapped and unlocked.
250 * Entry is guaranteed to be valid.
251 */
252 struct ufs_dir_entry *ufs_find_entry(struct inode *dir, struct dentry *dentry,
253 struct page **res_page)
254 {
255 struct super_block *sb = dir->i_sb;
256 const char *name = dentry->d_name.name;
257 int namelen = dentry->d_name.len;
258 unsigned reclen = UFS_DIR_REC_LEN(namelen);
259 unsigned long start, n;
260 unsigned long npages = ufs_dir_pages(dir);
261 struct page *page = NULL;
262 struct ufs_inode_info *ui = UFS_I(dir);
263 struct ufs_dir_entry *de;
264
265 UFSD("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen);
266
267 if (npages == 0 || namelen > UFS_MAXNAMLEN)
268 goto out;
269
270 /* OFFSET_CACHE */
271 *res_page = NULL;
272
273 start = ui->i_dir_start_lookup;
274
275 if (start >= npages)
276 start = 0;
277 n = start;
278 do {
279 char *kaddr;
280 page = ufs_get_page(dir, n);
281 if (!IS_ERR(page)) {
282 kaddr = page_address(page);
283 de = (struct ufs_dir_entry *) kaddr;
284 kaddr += ufs_last_byte(dir, n) - reclen;
285 while ((char *) de <= kaddr) {
286 if (de->d_reclen == 0) {
287 ufs_error(dir->i_sb, __FUNCTION__,
288 "zero-length directory entry");
289 ufs_put_page(page);
290 goto out;
291 }
292 if (ufs_match(sb, namelen, name, de))
293 goto found;
294 de = ufs_next_entry(sb, de);
295 }
296 ufs_put_page(page);
297 }
298 if (++n >= npages)
299 n = 0;
300 } while (n != start);
301 out:
302 return NULL;
303
304 found:
305 *res_page = page;
306 ui->i_dir_start_lookup = n;
307 return de;
308 }
309
310 /*
311 * Parent is locked.
312 */
313 int ufs_add_link(struct dentry *dentry, struct inode *inode)
314 {
315 struct inode *dir = dentry->d_parent->d_inode;
316 const char *name = dentry->d_name.name;
317 int namelen = dentry->d_name.len;
318 struct super_block *sb = dir->i_sb;
319 unsigned reclen = UFS_DIR_REC_LEN(namelen);
320 const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize;
321 unsigned short rec_len, name_len;
322 struct page *page = NULL;
323 struct ufs_dir_entry *de;
324 unsigned long npages = ufs_dir_pages(dir);
325 unsigned long n;
326 char *kaddr;
327 loff_t pos;
328 int err;
329
330 UFSD("ENTER, name %s, namelen %u\n", name, namelen);
331
332 /*
333 * We take care of directory expansion in the same loop.
334 * This code plays outside i_size, so it locks the page
335 * to protect that region.
336 */
337 for (n = 0; n <= npages; n++) {
338 char *dir_end;
339
340 page = ufs_get_page(dir, n);
341 err = PTR_ERR(page);
342 if (IS_ERR(page))
343 goto out;
344 lock_page(page);
345 kaddr = page_address(page);
346 dir_end = kaddr + ufs_last_byte(dir, n);
347 de = (struct ufs_dir_entry *)kaddr;
348 kaddr += PAGE_CACHE_SIZE - reclen;
349 while ((char *)de <= kaddr) {
350 if ((char *)de == dir_end) {
351 /* We hit i_size */
352 name_len = 0;
353 rec_len = chunk_size;
354 de->d_reclen = cpu_to_fs16(sb, chunk_size);
355 de->d_ino = 0;
356 goto got_it;
357 }
358 if (de->d_reclen == 0) {
359 ufs_error(dir->i_sb, __FUNCTION__,
360 "zero-length directory entry");
361 err = -EIO;
362 goto out_unlock;
363 }
364 err = -EEXIST;
365 if (ufs_match(sb, namelen, name, de))
366 goto out_unlock;
367 name_len = UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de));
368 rec_len = fs16_to_cpu(sb, de->d_reclen);
369 if (!de->d_ino && rec_len >= reclen)
370 goto got_it;
371 if (rec_len >= name_len + reclen)
372 goto got_it;
373 de = (struct ufs_dir_entry *) ((char *) de + rec_len);
374 }
375 unlock_page(page);
376 ufs_put_page(page);
377 }
378 BUG();
379 return -EINVAL;
380
381 got_it:
382 pos = page_offset(page) +
383 (char*)de - (char*)page_address(page);
384 err = __ufs_write_begin(NULL, page->mapping, pos, rec_len,
385 AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
386 if (err)
387 goto out_unlock;
388 if (de->d_ino) {
389 struct ufs_dir_entry *de1 =
390 (struct ufs_dir_entry *) ((char *) de + name_len);
391 de1->d_reclen = cpu_to_fs16(sb, rec_len - name_len);
392 de->d_reclen = cpu_to_fs16(sb, name_len);
393
394 de = de1;
395 }
396
397 ufs_set_de_namlen(sb, de, namelen);
398 memcpy(de->d_name, name, namelen + 1);
399 de->d_ino = cpu_to_fs32(sb, inode->i_ino);
400 ufs_set_de_type(sb, de, inode->i_mode);
401
402 err = ufs_commit_chunk(page, pos, rec_len);
403 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
404
405 mark_inode_dirty(dir);
406 /* OFFSET_CACHE */
407 out_put:
408 ufs_put_page(page);
409 out:
410 return err;
411 out_unlock:
412 unlock_page(page);
413 goto out_put;
414 }
415
416 static inline unsigned
417 ufs_validate_entry(struct super_block *sb, char *base,
418 unsigned offset, unsigned mask)
419 {
420 struct ufs_dir_entry *de = (struct ufs_dir_entry*)(base + offset);
421 struct ufs_dir_entry *p = (struct ufs_dir_entry*)(base + (offset&mask));
422 while ((char*)p < (char*)de) {
423 if (p->d_reclen == 0)
424 break;
425 p = ufs_next_entry(sb, p);
426 }
427 return (char *)p - base;
428 }
429
430
431 /*
432 * This is blatantly stolen from ext2fs
433 */
434 static int
435 ufs_readdir(struct file *filp, void *dirent, filldir_t filldir)
436 {
437 loff_t pos = filp->f_pos;
438 struct inode *inode = filp->f_path.dentry->d_inode;
439 struct super_block *sb = inode->i_sb;
440 unsigned int offset = pos & ~PAGE_CACHE_MASK;
441 unsigned long n = pos >> PAGE_CACHE_SHIFT;
442 unsigned long npages = ufs_dir_pages(inode);
443 unsigned chunk_mask = ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
444 int need_revalidate = filp->f_version != inode->i_version;
445 unsigned flags = UFS_SB(sb)->s_flags;
446
447 UFSD("BEGIN\n");
448
449 if (pos > inode->i_size - UFS_DIR_REC_LEN(1))
450 return 0;
451
452 for ( ; n < npages; n++, offset = 0) {
453 char *kaddr, *limit;
454 struct ufs_dir_entry *de;
455
456 struct page *page = ufs_get_page(inode, n);
457
458 if (IS_ERR(page)) {
459 ufs_error(sb, __FUNCTION__,
460 "bad page in #%lu",
461 inode->i_ino);
462 filp->f_pos += PAGE_CACHE_SIZE - offset;
463 return -EIO;
464 }
465 kaddr = page_address(page);
466 if (unlikely(need_revalidate)) {
467 if (offset) {
468 offset = ufs_validate_entry(sb, kaddr, offset, chunk_mask);
469 filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset;
470 }
471 filp->f_version = inode->i_version;
472 need_revalidate = 0;
473 }
474 de = (struct ufs_dir_entry *)(kaddr+offset);
475 limit = kaddr + ufs_last_byte(inode, n) - UFS_DIR_REC_LEN(1);
476 for ( ;(char*)de <= limit; de = ufs_next_entry(sb, de)) {
477 if (de->d_reclen == 0) {
478 ufs_error(sb, __FUNCTION__,
479 "zero-length directory entry");
480 ufs_put_page(page);
481 return -EIO;
482 }
483 if (de->d_ino) {
484 int over;
485 unsigned char d_type = DT_UNKNOWN;
486
487 offset = (char *)de - kaddr;
488
489 UFSD("filldir(%s,%u)\n", de->d_name,
490 fs32_to_cpu(sb, de->d_ino));
491 UFSD("namlen %u\n", ufs_get_de_namlen(sb, de));
492
493 if ((flags & UFS_DE_MASK) == UFS_DE_44BSD)
494 d_type = de->d_u.d_44.d_type;
495
496 over = filldir(dirent, de->d_name,
497 ufs_get_de_namlen(sb, de),
498 (n<<PAGE_CACHE_SHIFT) | offset,
499 fs32_to_cpu(sb, de->d_ino), d_type);
500 if (over) {
501 ufs_put_page(page);
502 return 0;
503 }
504 }
505 filp->f_pos += fs16_to_cpu(sb, de->d_reclen);
506 }
507 ufs_put_page(page);
508 }
509 return 0;
510 }
511
512
513 /*
514 * ufs_delete_entry deletes a directory entry by merging it with the
515 * previous entry.
516 */
517 int ufs_delete_entry(struct inode *inode, struct ufs_dir_entry *dir,
518 struct page * page)
519 {
520 struct super_block *sb = inode->i_sb;
521 struct address_space *mapping = page->mapping;
522 char *kaddr = page_address(page);
523 unsigned from = ((char*)dir - kaddr) & ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
524 unsigned to = ((char*)dir - kaddr) + fs16_to_cpu(sb, dir->d_reclen);
525 loff_t pos;
526 struct ufs_dir_entry *pde = NULL;
527 struct ufs_dir_entry *de = (struct ufs_dir_entry *) (kaddr + from);
528 int err;
529
530 UFSD("ENTER\n");
531
532 UFSD("ino %u, reclen %u, namlen %u, name %s\n",
533 fs32_to_cpu(sb, de->d_ino),
534 fs16_to_cpu(sb, de->d_reclen),
535 ufs_get_de_namlen(sb, de), de->d_name);
536
537 while ((char*)de < (char*)dir) {
538 if (de->d_reclen == 0) {
539 ufs_error(inode->i_sb, __FUNCTION__,
540 "zero-length directory entry");
541 err = -EIO;
542 goto out;
543 }
544 pde = de;
545 de = ufs_next_entry(sb, de);
546 }
547 if (pde)
548 from = (char*)pde - (char*)page_address(page);
549
550 pos = page_offset(page) + from;
551 lock_page(page);
552 err = __ufs_write_begin(NULL, mapping, pos, to - from,
553 AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
554 BUG_ON(err);
555 if (pde)
556 pde->d_reclen = cpu_to_fs16(sb, to - from);
557 dir->d_ino = 0;
558 err = ufs_commit_chunk(page, pos, to - from);
559 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
560 mark_inode_dirty(inode);
561 out:
562 ufs_put_page(page);
563 UFSD("EXIT\n");
564 return err;
565 }
566
567 int ufs_make_empty(struct inode * inode, struct inode *dir)
568 {
569 struct super_block * sb = dir->i_sb;
570 struct address_space *mapping = inode->i_mapping;
571 struct page *page = grab_cache_page(mapping, 0);
572 const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize;
573 struct ufs_dir_entry * de;
574 char *base;
575 int err;
576
577 if (!page)
578 return -ENOMEM;
579
580 err = __ufs_write_begin(NULL, mapping, 0, chunk_size,
581 AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
582 if (err) {
583 unlock_page(page);
584 goto fail;
585 }
586
587 kmap(page);
588 base = (char*)page_address(page);
589 memset(base, 0, PAGE_CACHE_SIZE);
590
591 de = (struct ufs_dir_entry *) base;
592
593 de->d_ino = cpu_to_fs32(sb, inode->i_ino);
594 ufs_set_de_type(sb, de, inode->i_mode);
595 ufs_set_de_namlen(sb, de, 1);
596 de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1));
597 strcpy (de->d_name, ".");
598 de = (struct ufs_dir_entry *)
599 ((char *)de + fs16_to_cpu(sb, de->d_reclen));
600 de->d_ino = cpu_to_fs32(sb, dir->i_ino);
601 ufs_set_de_type(sb, de, dir->i_mode);
602 de->d_reclen = cpu_to_fs16(sb, chunk_size - UFS_DIR_REC_LEN(1));
603 ufs_set_de_namlen(sb, de, 2);
604 strcpy (de->d_name, "..");
605 kunmap(page);
606
607 err = ufs_commit_chunk(page, 0, chunk_size);
608 fail:
609 page_cache_release(page);
610 return err;
611 }
612
613 /*
614 * routine to check that the specified directory is empty (for rmdir)
615 */
616 int ufs_empty_dir(struct inode * inode)
617 {
618 struct super_block *sb = inode->i_sb;
619 struct page *page = NULL;
620 unsigned long i, npages = ufs_dir_pages(inode);
621
622 for (i = 0; i < npages; i++) {
623 char *kaddr;
624 struct ufs_dir_entry *de;
625 page = ufs_get_page(inode, i);
626
627 if (IS_ERR(page))
628 continue;
629
630 kaddr = page_address(page);
631 de = (struct ufs_dir_entry *)kaddr;
632 kaddr += ufs_last_byte(inode, i) - UFS_DIR_REC_LEN(1);
633
634 while ((char *)de <= kaddr) {
635 if (de->d_reclen == 0) {
636 ufs_error(inode->i_sb, __FUNCTION__,
637 "zero-length directory entry: "
638 "kaddr=%p, de=%p\n", kaddr, de);
639 goto not_empty;
640 }
641 if (de->d_ino) {
642 u16 namelen=ufs_get_de_namlen(sb, de);
643 /* check for . and .. */
644 if (de->d_name[0] != '.')
645 goto not_empty;
646 if (namelen > 2)
647 goto not_empty;
648 if (namelen < 2) {
649 if (inode->i_ino !=
650 fs32_to_cpu(sb, de->d_ino))
651 goto not_empty;
652 } else if (de->d_name[1] != '.')
653 goto not_empty;
654 }
655 de = ufs_next_entry(sb, de);
656 }
657 ufs_put_page(page);
658 }
659 return 1;
660
661 not_empty:
662 ufs_put_page(page);
663 return 0;
664 }
665
666 const struct file_operations ufs_dir_operations = {
667 .read = generic_read_dir,
668 .readdir = ufs_readdir,
669 .fsync = file_fsync,
670 };
671
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