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ACPI: thinkpad-acpi: duplicate driver attributes to new hwmon pdrv
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / ext2 / dir.c
blob2bf49d7ef841423d03c44527e1578f7f8c4a2f38
1 /*
2 * linux/fs/ext2/dir.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/dir.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * ext2 directory handling functions
16 *
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
19 *
20 * All code that works with directory layout had been switched to pagecache
21 * and moved here. AV
22 */
23
24 #include "ext2.h"
25 #include <linux/pagemap.h>
26
27 typedef struct ext2_dir_entry_2 ext2_dirent;
28
29 /*
30 * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
31 * more robust, but we have what we have
32 */
33 static inline unsigned ext2_chunk_size(struct inode *inode)
34 {
35 return inode->i_sb->s_blocksize;
36 }
37
38 static inline void ext2_put_page(struct page *page)
39 {
40 kunmap(page);
41 page_cache_release(page);
42 }
43
44 static inline unsigned long dir_pages(struct inode *inode)
45 {
46 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
47 }
48
49 /*
50 * Return the offset into page `page_nr' of the last valid
51 * byte in that page, plus one.
52 */
53 static unsigned
54 ext2_last_byte(struct inode *inode, unsigned long page_nr)
55 {
56 unsigned last_byte = inode->i_size;
57
58 last_byte -= page_nr << PAGE_CACHE_SHIFT;
59 if (last_byte > PAGE_CACHE_SIZE)
60 last_byte = PAGE_CACHE_SIZE;
61 return last_byte;
62 }
63
64 static int ext2_commit_chunk(struct page *page, unsigned from, unsigned to)
65 {
66 struct inode *dir = page->mapping->host;
67 int err = 0;
68 dir->i_version++;
69 page->mapping->a_ops->commit_write(NULL, page, from, to);
70 if (IS_DIRSYNC(dir))
71 err = write_one_page(page, 1);
72 else
73 unlock_page(page);
74 return err;
75 }
76
77 static void ext2_check_page(struct page *page)
78 {
79 struct inode *dir = page->mapping->host;
80 struct super_block *sb = dir->i_sb;
81 unsigned chunk_size = ext2_chunk_size(dir);
82 char *kaddr = page_address(page);
83 u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
84 unsigned offs, rec_len;
85 unsigned limit = PAGE_CACHE_SIZE;
86 ext2_dirent *p;
87 char *error;
88
89 if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
90 limit = dir->i_size & ~PAGE_CACHE_MASK;
91 if (limit & (chunk_size - 1))
92 goto Ebadsize;
93 if (!limit)
94 goto out;
95 }
96 for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
97 p = (ext2_dirent *)(kaddr + offs);
98 rec_len = le16_to_cpu(p->rec_len);
99
100 if (rec_len < EXT2_DIR_REC_LEN(1))
101 goto Eshort;
102 if (rec_len & 3)
103 goto Ealign;
104 if (rec_len < EXT2_DIR_REC_LEN(p->name_len))
105 goto Enamelen;
106 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
107 goto Espan;
108 if (le32_to_cpu(p->inode) > max_inumber)
109 goto Einumber;
110 }
111 if (offs != limit)
112 goto Eend;
113 out:
114 SetPageChecked(page);
115 return;
116
117 /* Too bad, we had an error */
118
119 Ebadsize:
120 ext2_error(sb, "ext2_check_page",
121 "size of directory #%lu is not a multiple of chunk size",
122 dir->i_ino
123 );
124 goto fail;
125 Eshort:
126 error = "rec_len is smaller than minimal";
127 goto bad_entry;
128 Ealign:
129 error = "unaligned directory entry";
130 goto bad_entry;
131 Enamelen:
132 error = "rec_len is too small for name_len";
133 goto bad_entry;
134 Espan:
135 error = "directory entry across blocks";
136 goto bad_entry;
137 Einumber:
138 error = "inode out of bounds";
139 bad_entry:
140 ext2_error (sb, "ext2_check_page", "bad entry in directory #%lu: %s - "
141 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
142 dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
143 (unsigned long) le32_to_cpu(p->inode),
144 rec_len, p->name_len);
145 goto fail;
146 Eend:
147 p = (ext2_dirent *)(kaddr + offs);
148 ext2_error (sb, "ext2_check_page",
149 "entry in directory #%lu spans the page boundary"
150 "offset=%lu, inode=%lu",
151 dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
152 (unsigned long) le32_to_cpu(p->inode));
153 fail:
154 SetPageChecked(page);
155 SetPageError(page);
156 }
157
158 static struct page * ext2_get_page(struct inode *dir, unsigned long n)
159 {
160 struct address_space *mapping = dir->i_mapping;
161 struct page *page = read_mapping_page(mapping, n, NULL);
162 if (!IS_ERR(page)) {
163 kmap(page);
164 if (!PageChecked(page))
165 ext2_check_page(page);
166 if (PageError(page))
167 goto fail;
168 }
169 return page;
170
171 fail:
172 ext2_put_page(page);
173 return ERR_PTR(-EIO);
174 }
175
176 /*
177 * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
178 *
179 * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
180 */
181 static inline int ext2_match (int len, const char * const name,
182 struct ext2_dir_entry_2 * de)
183 {
184 if (len != de->name_len)
185 return 0;
186 if (!de->inode)
187 return 0;
188 return !memcmp(name, de->name, len);
189 }
190
191 /*
192 * p is at least 6 bytes before the end of page
193 */
194 static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
195 {
196 return (ext2_dirent *)((char*)p + le16_to_cpu(p->rec_len));
197 }
198
199 static inline unsigned
200 ext2_validate_entry(char *base, unsigned offset, unsigned mask)
201 {
202 ext2_dirent *de = (ext2_dirent*)(base + offset);
203 ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
204 while ((char*)p < (char*)de) {
205 if (p->rec_len == 0)
206 break;
207 p = ext2_next_entry(p);
208 }
209 return (char *)p - base;
210 }
211
212 static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
213 [EXT2_FT_UNKNOWN] = DT_UNKNOWN,
214 [EXT2_FT_REG_FILE] = DT_REG,
215 [EXT2_FT_DIR] = DT_DIR,
216 [EXT2_FT_CHRDEV] = DT_CHR,
217 [EXT2_FT_BLKDEV] = DT_BLK,
218 [EXT2_FT_FIFO] = DT_FIFO,
219 [EXT2_FT_SOCK] = DT_SOCK,
220 [EXT2_FT_SYMLINK] = DT_LNK,
221 };
222
223 #define S_SHIFT 12
224 static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = {
225 [S_IFREG >> S_SHIFT] = EXT2_FT_REG_FILE,
226 [S_IFDIR >> S_SHIFT] = EXT2_FT_DIR,
227 [S_IFCHR >> S_SHIFT] = EXT2_FT_CHRDEV,
228 [S_IFBLK >> S_SHIFT] = EXT2_FT_BLKDEV,
229 [S_IFIFO >> S_SHIFT] = EXT2_FT_FIFO,
230 [S_IFSOCK >> S_SHIFT] = EXT2_FT_SOCK,
231 [S_IFLNK >> S_SHIFT] = EXT2_FT_SYMLINK,
232 };
233
234 static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
235 {
236 mode_t mode = inode->i_mode;
237 if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
238 de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
239 else
240 de->file_type = 0;
241 }
242
243 static int
244 ext2_readdir (struct file * filp, void * dirent, filldir_t filldir)
245 {
246 loff_t pos = filp->f_pos;
247 struct inode *inode = filp->f_path.dentry->d_inode;
248 struct super_block *sb = inode->i_sb;
249 unsigned int offset = pos & ~PAGE_CACHE_MASK;
250 unsigned long n = pos >> PAGE_CACHE_SHIFT;
251 unsigned long npages = dir_pages(inode);
252 unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
253 unsigned char *types = NULL;
254 int need_revalidate = filp->f_version != inode->i_version;
255
256 if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
257 return 0;
258
259 if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
260 types = ext2_filetype_table;
261
262 for ( ; n < npages; n++, offset = 0) {
263 char *kaddr, *limit;
264 ext2_dirent *de;
265 struct page *page = ext2_get_page(inode, n);
266
267 if (IS_ERR(page)) {
268 ext2_error(sb, __FUNCTION__,
269 "bad page in #%lu",
270 inode->i_ino);
271 filp->f_pos += PAGE_CACHE_SIZE - offset;
272 return -EIO;
273 }
274 kaddr = page_address(page);
275 if (unlikely(need_revalidate)) {
276 if (offset) {
277 offset = ext2_validate_entry(kaddr, offset, chunk_mask);
278 filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset;
279 }
280 filp->f_version = inode->i_version;
281 need_revalidate = 0;
282 }
283 de = (ext2_dirent *)(kaddr+offset);
284 limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1);
285 for ( ;(char*)de <= limit; de = ext2_next_entry(de)) {
286 if (de->rec_len == 0) {
287 ext2_error(sb, __FUNCTION__,
288 "zero-length directory entry");
289 ext2_put_page(page);
290 return -EIO;
291 }
292 if (de->inode) {
293 int over;
294 unsigned char d_type = DT_UNKNOWN;
295
296 if (types && de->file_type < EXT2_FT_MAX)
297 d_type = types[de->file_type];
298
299 offset = (char *)de - kaddr;
300 over = filldir(dirent, de->name, de->name_len,
301 (n<<PAGE_CACHE_SHIFT) | offset,
302 le32_to_cpu(de->inode), d_type);
303 if (over) {
304 ext2_put_page(page);
305 return 0;
306 }
307 }
308 filp->f_pos += le16_to_cpu(de->rec_len);
309 }
310 ext2_put_page(page);
311 }
312 return 0;
313 }
314
315 /*
316 * ext2_find_entry()
317 *
318 * finds an entry in the specified directory with the wanted name. It
319 * returns the page in which the entry was found, and the entry itself
320 * (as a parameter - res_dir). Page is returned mapped and unlocked.
321 * Entry is guaranteed to be valid.
322 */
323 struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir,
324 struct dentry *dentry, struct page ** res_page)
325 {
326 const char *name = dentry->d_name.name;
327 int namelen = dentry->d_name.len;
328 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
329 unsigned long start, n;
330 unsigned long npages = dir_pages(dir);
331 struct page *page = NULL;
332 struct ext2_inode_info *ei = EXT2_I(dir);
333 ext2_dirent * de;
334
335 if (npages == 0)
336 goto out;
337
338 /* OFFSET_CACHE */
339 *res_page = NULL;
340
341 start = ei->i_dir_start_lookup;
342 if (start >= npages)
343 start = 0;
344 n = start;
345 do {
346 char *kaddr;
347 page = ext2_get_page(dir, n);
348 if (!IS_ERR(page)) {
349 kaddr = page_address(page);
350 de = (ext2_dirent *) kaddr;
351 kaddr += ext2_last_byte(dir, n) - reclen;
352 while ((char *) de <= kaddr) {
353 if (de->rec_len == 0) {
354 ext2_error(dir->i_sb, __FUNCTION__,
355 "zero-length directory entry");
356 ext2_put_page(page);
357 goto out;
358 }
359 if (ext2_match (namelen, name, de))
360 goto found;
361 de = ext2_next_entry(de);
362 }
363 ext2_put_page(page);
364 }
365 if (++n >= npages)
366 n = 0;
367 /* next page is past the blocks we've got */
368 if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) {
369 ext2_error(dir->i_sb, __FUNCTION__,
370 "dir %lu size %lld exceeds block count %llu",
371 dir->i_ino, dir->i_size,
372 (unsigned long long)dir->i_blocks);
373 goto out;
374 }
375 } while (n != start);
376 out:
377 return NULL;
378
379 found:
380 *res_page = page;
381 ei->i_dir_start_lookup = n;
382 return de;
383 }
384
385 struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
386 {
387 struct page *page = ext2_get_page(dir, 0);
388 ext2_dirent *de = NULL;
389
390 if (!IS_ERR(page)) {
391 de = ext2_next_entry((ext2_dirent *) page_address(page));
392 *p = page;
393 }
394 return de;
395 }
396
397 ino_t ext2_inode_by_name(struct inode * dir, struct dentry *dentry)
398 {
399 ino_t res = 0;
400 struct ext2_dir_entry_2 * de;
401 struct page *page;
402
403 de = ext2_find_entry (dir, dentry, &page);
404 if (de) {
405 res = le32_to_cpu(de->inode);
406 ext2_put_page(page);
407 }
408 return res;
409 }
410
411 /* Releases the page */
412 void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
413 struct page *page, struct inode *inode)
414 {
415 unsigned from = (char *) de - (char *) page_address(page);
416 unsigned to = from + le16_to_cpu(de->rec_len);
417 int err;
418
419 lock_page(page);
420 err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
421 BUG_ON(err);
422 de->inode = cpu_to_le32(inode->i_ino);
423 ext2_set_de_type (de, inode);
424 err = ext2_commit_chunk(page, from, to);
425 ext2_put_page(page);
426 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
427 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
428 mark_inode_dirty(dir);
429 }
430
431 /*
432 * Parent is locked.
433 */
434 int ext2_add_link (struct dentry *dentry, struct inode *inode)
435 {
436 struct inode *dir = dentry->d_parent->d_inode;
437 const char *name = dentry->d_name.name;
438 int namelen = dentry->d_name.len;
439 unsigned chunk_size = ext2_chunk_size(dir);
440 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
441 unsigned short rec_len, name_len;
442 struct page *page = NULL;
443 ext2_dirent * de;
444 unsigned long npages = dir_pages(dir);
445 unsigned long n;
446 char *kaddr;
447 unsigned from, to;
448 int err;
449
450 /*
451 * We take care of directory expansion in the same loop.
452 * This code plays outside i_size, so it locks the page
453 * to protect that region.
454 */
455 for (n = 0; n <= npages; n++) {
456 char *dir_end;
457
458 page = ext2_get_page(dir, n);
459 err = PTR_ERR(page);
460 if (IS_ERR(page))
461 goto out;
462 lock_page(page);
463 kaddr = page_address(page);
464 dir_end = kaddr + ext2_last_byte(dir, n);
465 de = (ext2_dirent *)kaddr;
466 kaddr += PAGE_CACHE_SIZE - reclen;
467 while ((char *)de <= kaddr) {
468 if ((char *)de == dir_end) {
469 /* We hit i_size */
470 name_len = 0;
471 rec_len = chunk_size;
472 de->rec_len = cpu_to_le16(chunk_size);
473 de->inode = 0;
474 goto got_it;
475 }
476 if (de->rec_len == 0) {
477 ext2_error(dir->i_sb, __FUNCTION__,
478 "zero-length directory entry");
479 err = -EIO;
480 goto out_unlock;
481 }
482 err = -EEXIST;
483 if (ext2_match (namelen, name, de))
484 goto out_unlock;
485 name_len = EXT2_DIR_REC_LEN(de->name_len);
486 rec_len = le16_to_cpu(de->rec_len);
487 if (!de->inode && rec_len >= reclen)
488 goto got_it;
489 if (rec_len >= name_len + reclen)
490 goto got_it;
491 de = (ext2_dirent *) ((char *) de + rec_len);
492 }
493 unlock_page(page);
494 ext2_put_page(page);
495 }
496 BUG();
497 return -EINVAL;
498
499 got_it:
500 from = (char*)de - (char*)page_address(page);
501 to = from + rec_len;
502 err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
503 if (err)
504 goto out_unlock;
505 if (de->inode) {
506 ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
507 de1->rec_len = cpu_to_le16(rec_len - name_len);
508 de->rec_len = cpu_to_le16(name_len);
509 de = de1;
510 }
511 de->name_len = namelen;
512 memcpy (de->name, name, namelen);
513 de->inode = cpu_to_le32(inode->i_ino);
514 ext2_set_de_type (de, inode);
515 err = ext2_commit_chunk(page, from, to);
516 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
517 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
518 mark_inode_dirty(dir);
519 /* OFFSET_CACHE */
520 out_put:
521 ext2_put_page(page);
522 out:
523 return err;
524 out_unlock:
525 unlock_page(page);
526 goto out_put;
527 }
528
529 /*
530 * ext2_delete_entry deletes a directory entry by merging it with the
531 * previous entry. Page is up-to-date. Releases the page.
532 */
533 int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
534 {
535 struct address_space *mapping = page->mapping;
536 struct inode *inode = mapping->host;
537 char *kaddr = page_address(page);
538 unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
539 unsigned to = ((char*)dir - kaddr) + le16_to_cpu(dir->rec_len);
540 ext2_dirent * pde = NULL;
541 ext2_dirent * de = (ext2_dirent *) (kaddr + from);
542 int err;
543
544 while ((char*)de < (char*)dir) {
545 if (de->rec_len == 0) {
546 ext2_error(inode->i_sb, __FUNCTION__,
547 "zero-length directory entry");
548 err = -EIO;
549 goto out;
550 }
551 pde = de;
552 de = ext2_next_entry(de);
553 }
554 if (pde)
555 from = (char*)pde - (char*)page_address(page);
556 lock_page(page);
557 err = mapping->a_ops->prepare_write(NULL, page, from, to);
558 BUG_ON(err);
559 if (pde)
560 pde->rec_len = cpu_to_le16(to-from);
561 dir->inode = 0;
562 err = ext2_commit_chunk(page, from, to);
563 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
564 EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL;
565 mark_inode_dirty(inode);
566 out:
567 ext2_put_page(page);
568 return err;
569 }
570
571 /*
572 * Set the first fragment of directory.
573 */
574 int ext2_make_empty(struct inode *inode, struct inode *parent)
575 {
576 struct address_space *mapping = inode->i_mapping;
577 struct page *page = grab_cache_page(mapping, 0);
578 unsigned chunk_size = ext2_chunk_size(inode);
579 struct ext2_dir_entry_2 * de;
580 int err;
581 void *kaddr;
582
583 if (!page)
584 return -ENOMEM;
585 err = mapping->a_ops->prepare_write(NULL, page, 0, chunk_size);
586 if (err) {
587 unlock_page(page);
588 goto fail;
589 }
590 kaddr = kmap_atomic(page, KM_USER0);
591 memset(kaddr, 0, chunk_size);
592 de = (struct ext2_dir_entry_2 *)kaddr;
593 de->name_len = 1;
594 de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(1));
595 memcpy (de->name, ".\0\0", 4);
596 de->inode = cpu_to_le32(inode->i_ino);
597 ext2_set_de_type (de, inode);
598
599 de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1));
600 de->name_len = 2;
601 de->rec_len = cpu_to_le16(chunk_size - EXT2_DIR_REC_LEN(1));
602 de->inode = cpu_to_le32(parent->i_ino);
603 memcpy (de->name, "..\0", 4);
604 ext2_set_de_type (de, inode);
605 kunmap_atomic(kaddr, KM_USER0);
606 err = ext2_commit_chunk(page, 0, chunk_size);
607 fail:
608 page_cache_release(page);
609 return err;
610 }
611
612 /*
613 * routine to check that the specified directory is empty (for rmdir)
614 */
615 int ext2_empty_dir (struct inode * inode)
616 {
617 struct page *page = NULL;
618 unsigned long i, npages = dir_pages(inode);
619
620 for (i = 0; i < npages; i++) {
621 char *kaddr;
622 ext2_dirent * de;
623 page = ext2_get_page(inode, i);
624
625 if (IS_ERR(page))
626 continue;
627
628 kaddr = page_address(page);
629 de = (ext2_dirent *)kaddr;
630 kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1);
631
632 while ((char *)de <= kaddr) {
633 if (de->rec_len == 0) {
634 ext2_error(inode->i_sb, __FUNCTION__,
635 "zero-length directory entry");
636 printk("kaddr=%p, de=%p\n", kaddr, de);
637 goto not_empty;
638 }
639 if (de->inode != 0) {
640 /* check for . and .. */
641 if (de->name[0] != '.')
642 goto not_empty;
643 if (de->name_len > 2)
644 goto not_empty;
645 if (de->name_len < 2) {
646 if (de->inode !=
647 cpu_to_le32(inode->i_ino))
648 goto not_empty;
649 } else if (de->name[1] != '.')
650 goto not_empty;
651 }
652 de = ext2_next_entry(de);
653 }
654 ext2_put_page(page);
655 }
656 return 1;
657
658 not_empty:
659 ext2_put_page(page);
660 return 0;
661 }
662
663 const struct file_operations ext2_dir_operations = {
664 .llseek = generic_file_llseek,
665 .read = generic_read_dir,
666 .readdir = ext2_readdir,
667 .ioctl = ext2_ioctl,
668 #ifdef CONFIG_COMPAT
669 .compat_ioctl = ext2_compat_ioctl,
670 #endif
671 .fsync = ext2_sync_file,
672 };
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree