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new helper: file_inode(file)
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / ext2 / dir.c
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/buffer_head.h>
26 #include <linux/pagemap.h>
27 #include <linux/swap.h>
28
29 typedef struct ext2_dir_entry_2 ext2_dirent;
30
31 /*
32 * Tests against MAX_REC_LEN etc were put in place for 64k block
33 * sizes; if that is not possible on this arch, we can skip
34 * those tests and speed things up.
35 */
36 static inline unsigned ext2_rec_len_from_disk(__le16 dlen)
37 {
38 unsigned len = le16_to_cpu(dlen);
39
40 #if (PAGE_CACHE_SIZE >= 65536)
41 if (len == EXT2_MAX_REC_LEN)
42 return 1 << 16;
43 #endif
44 return len;
45 }
46
47 static inline __le16 ext2_rec_len_to_disk(unsigned len)
48 {
49 #if (PAGE_CACHE_SIZE >= 65536)
50 if (len == (1 << 16))
51 return cpu_to_le16(EXT2_MAX_REC_LEN);
52 else
53 BUG_ON(len > (1 << 16));
54 #endif
55 return cpu_to_le16(len);
56 }
57
58 /*
59 * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
60 * more robust, but we have what we have
61 */
62 static inline unsigned ext2_chunk_size(struct inode *inode)
63 {
64 return inode->i_sb->s_blocksize;
65 }
66
67 static inline void ext2_put_page(struct page *page)
68 {
69 kunmap(page);
70 page_cache_release(page);
71 }
72
73 static inline unsigned long dir_pages(struct inode *inode)
74 {
75 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
76 }
77
78 /*
79 * Return the offset into page `page_nr' of the last valid
80 * byte in that page, plus one.
81 */
82 static unsigned
83 ext2_last_byte(struct inode *inode, unsigned long page_nr)
84 {
85 unsigned last_byte = inode->i_size;
86
87 last_byte -= page_nr << PAGE_CACHE_SHIFT;
88 if (last_byte > PAGE_CACHE_SIZE)
89 last_byte = PAGE_CACHE_SIZE;
90 return last_byte;
91 }
92
93 static int ext2_commit_chunk(struct page *page, loff_t pos, unsigned len)
94 {
95 struct address_space *mapping = page->mapping;
96 struct inode *dir = mapping->host;
97 int err = 0;
98
99 dir->i_version++;
100 block_write_end(NULL, mapping, pos, len, len, page, NULL);
101
102 if (pos+len > dir->i_size) {
103 i_size_write(dir, pos+len);
104 mark_inode_dirty(dir);
105 }
106
107 if (IS_DIRSYNC(dir)) {
108 err = write_one_page(page, 1);
109 if (!err)
110 err = sync_inode_metadata(dir, 1);
111 } else {
112 unlock_page(page);
113 }
114
115 return err;
116 }
117
118 static void ext2_check_page(struct page *page, int quiet)
119 {
120 struct inode *dir = page->mapping->host;
121 struct super_block *sb = dir->i_sb;
122 unsigned chunk_size = ext2_chunk_size(dir);
123 char *kaddr = page_address(page);
124 u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
125 unsigned offs, rec_len;
126 unsigned limit = PAGE_CACHE_SIZE;
127 ext2_dirent *p;
128 char *error;
129
130 if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
131 limit = dir->i_size & ~PAGE_CACHE_MASK;
132 if (limit & (chunk_size - 1))
133 goto Ebadsize;
134 if (!limit)
135 goto out;
136 }
137 for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
138 p = (ext2_dirent *)(kaddr + offs);
139 rec_len = ext2_rec_len_from_disk(p->rec_len);
140
141 if (unlikely(rec_len < EXT2_DIR_REC_LEN(1)))
142 goto Eshort;
143 if (unlikely(rec_len & 3))
144 goto Ealign;
145 if (unlikely(rec_len < EXT2_DIR_REC_LEN(p->name_len)))
146 goto Enamelen;
147 if (unlikely(((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)))
148 goto Espan;
149 if (unlikely(le32_to_cpu(p->inode) > max_inumber))
150 goto Einumber;
151 }
152 if (offs != limit)
153 goto Eend;
154 out:
155 SetPageChecked(page);
156 return;
157
158 /* Too bad, we had an error */
159
160 Ebadsize:
161 if (!quiet)
162 ext2_error(sb, __func__,
163 "size of directory #%lu is not a multiple "
164 "of chunk size", dir->i_ino);
165 goto fail;
166 Eshort:
167 error = "rec_len is smaller than minimal";
168 goto bad_entry;
169 Ealign:
170 error = "unaligned directory entry";
171 goto bad_entry;
172 Enamelen:
173 error = "rec_len is too small for name_len";
174 goto bad_entry;
175 Espan:
176 error = "directory entry across blocks";
177 goto bad_entry;
178 Einumber:
179 error = "inode out of bounds";
180 bad_entry:
181 if (!quiet)
182 ext2_error(sb, __func__, "bad entry in directory #%lu: : %s - "
183 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
184 dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
185 (unsigned long) le32_to_cpu(p->inode),
186 rec_len, p->name_len);
187 goto fail;
188 Eend:
189 if (!quiet) {
190 p = (ext2_dirent *)(kaddr + offs);
191 ext2_error(sb, "ext2_check_page",
192 "entry in directory #%lu spans the page boundary"
193 "offset=%lu, inode=%lu",
194 dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
195 (unsigned long) le32_to_cpu(p->inode));
196 }
197 fail:
198 SetPageChecked(page);
199 SetPageError(page);
200 }
201
202 static struct page * ext2_get_page(struct inode *dir, unsigned long n,
203 int quiet)
204 {
205 struct address_space *mapping = dir->i_mapping;
206 struct page *page = read_mapping_page(mapping, n, NULL);
207 if (!IS_ERR(page)) {
208 kmap(page);
209 if (!PageChecked(page))
210 ext2_check_page(page, quiet);
211 if (PageError(page))
212 goto fail;
213 }
214 return page;
215
216 fail:
217 ext2_put_page(page);
218 return ERR_PTR(-EIO);
219 }
220
221 /*
222 * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
223 *
224 * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
225 */
226 static inline int ext2_match (int len, const char * const name,
227 struct ext2_dir_entry_2 * de)
228 {
229 if (len != de->name_len)
230 return 0;
231 if (!de->inode)
232 return 0;
233 return !memcmp(name, de->name, len);
234 }
235
236 /*
237 * p is at least 6 bytes before the end of page
238 */
239 static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
240 {
241 return (ext2_dirent *)((char *)p +
242 ext2_rec_len_from_disk(p->rec_len));
243 }
244
245 static inline unsigned
246 ext2_validate_entry(char *base, unsigned offset, unsigned mask)
247 {
248 ext2_dirent *de = (ext2_dirent*)(base + offset);
249 ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
250 while ((char*)p < (char*)de) {
251 if (p->rec_len == 0)
252 break;
253 p = ext2_next_entry(p);
254 }
255 return (char *)p - base;
256 }
257
258 static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
259 [EXT2_FT_UNKNOWN] = DT_UNKNOWN,
260 [EXT2_FT_REG_FILE] = DT_REG,
261 [EXT2_FT_DIR] = DT_DIR,
262 [EXT2_FT_CHRDEV] = DT_CHR,
263 [EXT2_FT_BLKDEV] = DT_BLK,
264 [EXT2_FT_FIFO] = DT_FIFO,
265 [EXT2_FT_SOCK] = DT_SOCK,
266 [EXT2_FT_SYMLINK] = DT_LNK,
267 };
268
269 #define S_SHIFT 12
270 static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = {
271 [S_IFREG >> S_SHIFT] = EXT2_FT_REG_FILE,
272 [S_IFDIR >> S_SHIFT] = EXT2_FT_DIR,
273 [S_IFCHR >> S_SHIFT] = EXT2_FT_CHRDEV,
274 [S_IFBLK >> S_SHIFT] = EXT2_FT_BLKDEV,
275 [S_IFIFO >> S_SHIFT] = EXT2_FT_FIFO,
276 [S_IFSOCK >> S_SHIFT] = EXT2_FT_SOCK,
277 [S_IFLNK >> S_SHIFT] = EXT2_FT_SYMLINK,
278 };
279
280 static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
281 {
282 umode_t mode = inode->i_mode;
283 if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
284 de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
285 else
286 de->file_type = 0;
287 }
288
289 static int
290 ext2_readdir (struct file * filp, void * dirent, filldir_t filldir)
291 {
292 loff_t pos = filp->f_pos;
293 struct inode *inode = file_inode(filp);
294 struct super_block *sb = inode->i_sb;
295 unsigned int offset = pos & ~PAGE_CACHE_MASK;
296 unsigned long n = pos >> PAGE_CACHE_SHIFT;
297 unsigned long npages = dir_pages(inode);
298 unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
299 unsigned char *types = NULL;
300 int need_revalidate = filp->f_version != inode->i_version;
301
302 if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
303 return 0;
304
305 if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
306 types = ext2_filetype_table;
307
308 for ( ; n < npages; n++, offset = 0) {
309 char *kaddr, *limit;
310 ext2_dirent *de;
311 struct page *page = ext2_get_page(inode, n, 0);
312
313 if (IS_ERR(page)) {
314 ext2_error(sb, __func__,
315 "bad page in #%lu",
316 inode->i_ino);
317 filp->f_pos += PAGE_CACHE_SIZE - offset;
318 return PTR_ERR(page);
319 }
320 kaddr = page_address(page);
321 if (unlikely(need_revalidate)) {
322 if (offset) {
323 offset = ext2_validate_entry(kaddr, offset, chunk_mask);
324 filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset;
325 }
326 filp->f_version = inode->i_version;
327 need_revalidate = 0;
328 }
329 de = (ext2_dirent *)(kaddr+offset);
330 limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1);
331 for ( ;(char*)de <= limit; de = ext2_next_entry(de)) {
332 if (de->rec_len == 0) {
333 ext2_error(sb, __func__,
334 "zero-length directory entry");
335 ext2_put_page(page);
336 return -EIO;
337 }
338 if (de->inode) {
339 int over;
340 unsigned char d_type = DT_UNKNOWN;
341
342 if (types && de->file_type < EXT2_FT_MAX)
343 d_type = types[de->file_type];
344
345 offset = (char *)de - kaddr;
346 over = filldir(dirent, de->name, de->name_len,
347 (n<<PAGE_CACHE_SHIFT) | offset,
348 le32_to_cpu(de->inode), d_type);
349 if (over) {
350 ext2_put_page(page);
351 return 0;
352 }
353 }
354 filp->f_pos += ext2_rec_len_from_disk(de->rec_len);
355 }
356 ext2_put_page(page);
357 }
358 return 0;
359 }
360
361 /*
362 * ext2_find_entry()
363 *
364 * finds an entry in the specified directory with the wanted name. It
365 * returns the page in which the entry was found (as a parameter - res_page),
366 * and the entry itself. Page is returned mapped and unlocked.
367 * Entry is guaranteed to be valid.
368 */
369 struct ext2_dir_entry_2 *ext2_find_entry (struct inode * dir,
370 struct qstr *child, struct page ** res_page)
371 {
372 const char *name = child->name;
373 int namelen = child->len;
374 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
375 unsigned long start, n;
376 unsigned long npages = dir_pages(dir);
377 struct page *page = NULL;
378 struct ext2_inode_info *ei = EXT2_I(dir);
379 ext2_dirent * de;
380 int dir_has_error = 0;
381
382 if (npages == 0)
383 goto out;
384
385 /* OFFSET_CACHE */
386 *res_page = NULL;
387
388 start = ei->i_dir_start_lookup;
389 if (start >= npages)
390 start = 0;
391 n = start;
392 do {
393 char *kaddr;
394 page = ext2_get_page(dir, n, dir_has_error);
395 if (!IS_ERR(page)) {
396 kaddr = page_address(page);
397 de = (ext2_dirent *) kaddr;
398 kaddr += ext2_last_byte(dir, n) - reclen;
399 while ((char *) de <= kaddr) {
400 if (de->rec_len == 0) {
401 ext2_error(dir->i_sb, __func__,
402 "zero-length directory entry");
403 ext2_put_page(page);
404 goto out;
405 }
406 if (ext2_match (namelen, name, de))
407 goto found;
408 de = ext2_next_entry(de);
409 }
410 ext2_put_page(page);
411 } else
412 dir_has_error = 1;
413
414 if (++n >= npages)
415 n = 0;
416 /* next page is past the blocks we've got */
417 if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) {
418 ext2_error(dir->i_sb, __func__,
419 "dir %lu size %lld exceeds block count %llu",
420 dir->i_ino, dir->i_size,
421 (unsigned long long)dir->i_blocks);
422 goto out;
423 }
424 } while (n != start);
425 out:
426 return NULL;
427
428 found:
429 *res_page = page;
430 ei->i_dir_start_lookup = n;
431 return de;
432 }
433
434 struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
435 {
436 struct page *page = ext2_get_page(dir, 0, 0);
437 ext2_dirent *de = NULL;
438
439 if (!IS_ERR(page)) {
440 de = ext2_next_entry((ext2_dirent *) page_address(page));
441 *p = page;
442 }
443 return de;
444 }
445
446 ino_t ext2_inode_by_name(struct inode *dir, struct qstr *child)
447 {
448 ino_t res = 0;
449 struct ext2_dir_entry_2 *de;
450 struct page *page;
451
452 de = ext2_find_entry (dir, child, &page);
453 if (de) {
454 res = le32_to_cpu(de->inode);
455 ext2_put_page(page);
456 }
457 return res;
458 }
459
460 static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)
461 {
462 return __block_write_begin(page, pos, len, ext2_get_block);
463 }
464
465 /* Releases the page */
466 void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
467 struct page *page, struct inode *inode, int update_times)
468 {
469 loff_t pos = page_offset(page) +
470 (char *) de - (char *) page_address(page);
471 unsigned len = ext2_rec_len_from_disk(de->rec_len);
472 int err;
473
474 lock_page(page);
475 err = ext2_prepare_chunk(page, pos, len);
476 BUG_ON(err);
477 de->inode = cpu_to_le32(inode->i_ino);
478 ext2_set_de_type(de, inode);
479 err = ext2_commit_chunk(page, pos, len);
480 ext2_put_page(page);
481 if (update_times)
482 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
483 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
484 mark_inode_dirty(dir);
485 }
486
487 /*
488 * Parent is locked.
489 */
490 int ext2_add_link (struct dentry *dentry, struct inode *inode)
491 {
492 struct inode *dir = dentry->d_parent->d_inode;
493 const char *name = dentry->d_name.name;
494 int namelen = dentry->d_name.len;
495 unsigned chunk_size = ext2_chunk_size(dir);
496 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
497 unsigned short rec_len, name_len;
498 struct page *page = NULL;
499 ext2_dirent * de;
500 unsigned long npages = dir_pages(dir);
501 unsigned long n;
502 char *kaddr;
503 loff_t pos;
504 int err;
505
506 /*
507 * We take care of directory expansion in the same loop.
508 * This code plays outside i_size, so it locks the page
509 * to protect that region.
510 */
511 for (n = 0; n <= npages; n++) {
512 char *dir_end;
513
514 page = ext2_get_page(dir, n, 0);
515 err = PTR_ERR(page);
516 if (IS_ERR(page))
517 goto out;
518 lock_page(page);
519 kaddr = page_address(page);
520 dir_end = kaddr + ext2_last_byte(dir, n);
521 de = (ext2_dirent *)kaddr;
522 kaddr += PAGE_CACHE_SIZE - reclen;
523 while ((char *)de <= kaddr) {
524 if ((char *)de == dir_end) {
525 /* We hit i_size */
526 name_len = 0;
527 rec_len = chunk_size;
528 de->rec_len = ext2_rec_len_to_disk(chunk_size);
529 de->inode = 0;
530 goto got_it;
531 }
532 if (de->rec_len == 0) {
533 ext2_error(dir->i_sb, __func__,
534 "zero-length directory entry");
535 err = -EIO;
536 goto out_unlock;
537 }
538 err = -EEXIST;
539 if (ext2_match (namelen, name, de))
540 goto out_unlock;
541 name_len = EXT2_DIR_REC_LEN(de->name_len);
542 rec_len = ext2_rec_len_from_disk(de->rec_len);
543 if (!de->inode && rec_len >= reclen)
544 goto got_it;
545 if (rec_len >= name_len + reclen)
546 goto got_it;
547 de = (ext2_dirent *) ((char *) de + rec_len);
548 }
549 unlock_page(page);
550 ext2_put_page(page);
551 }
552 BUG();
553 return -EINVAL;
554
555 got_it:
556 pos = page_offset(page) +
557 (char*)de - (char*)page_address(page);
558 err = ext2_prepare_chunk(page, pos, rec_len);
559 if (err)
560 goto out_unlock;
561 if (de->inode) {
562 ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
563 de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len);
564 de->rec_len = ext2_rec_len_to_disk(name_len);
565 de = de1;
566 }
567 de->name_len = namelen;
568 memcpy(de->name, name, namelen);
569 de->inode = cpu_to_le32(inode->i_ino);
570 ext2_set_de_type (de, inode);
571 err = ext2_commit_chunk(page, pos, rec_len);
572 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
573 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
574 mark_inode_dirty(dir);
575 /* OFFSET_CACHE */
576 out_put:
577 ext2_put_page(page);
578 out:
579 return err;
580 out_unlock:
581 unlock_page(page);
582 goto out_put;
583 }
584
585 /*
586 * ext2_delete_entry deletes a directory entry by merging it with the
587 * previous entry. Page is up-to-date. Releases the page.
588 */
589 int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
590 {
591 struct inode *inode = page->mapping->host;
592 char *kaddr = page_address(page);
593 unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
594 unsigned to = ((char *)dir - kaddr) +
595 ext2_rec_len_from_disk(dir->rec_len);
596 loff_t pos;
597 ext2_dirent * pde = NULL;
598 ext2_dirent * de = (ext2_dirent *) (kaddr + from);
599 int err;
600
601 while ((char*)de < (char*)dir) {
602 if (de->rec_len == 0) {
603 ext2_error(inode->i_sb, __func__,
604 "zero-length directory entry");
605 err = -EIO;
606 goto out;
607 }
608 pde = de;
609 de = ext2_next_entry(de);
610 }
611 if (pde)
612 from = (char*)pde - (char*)page_address(page);
613 pos = page_offset(page) + from;
614 lock_page(page);
615 err = ext2_prepare_chunk(page, pos, to - from);
616 BUG_ON(err);
617 if (pde)
618 pde->rec_len = ext2_rec_len_to_disk(to - from);
619 dir->inode = 0;
620 err = ext2_commit_chunk(page, pos, to - from);
621 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
622 EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL;
623 mark_inode_dirty(inode);
624 out:
625 ext2_put_page(page);
626 return err;
627 }
628
629 /*
630 * Set the first fragment of directory.
631 */
632 int ext2_make_empty(struct inode *inode, struct inode *parent)
633 {
634 struct page *page = grab_cache_page(inode->i_mapping, 0);
635 unsigned chunk_size = ext2_chunk_size(inode);
636 struct ext2_dir_entry_2 * de;
637 int err;
638 void *kaddr;
639
640 if (!page)
641 return -ENOMEM;
642
643 err = ext2_prepare_chunk(page, 0, chunk_size);
644 if (err) {
645 unlock_page(page);
646 goto fail;
647 }
648 kaddr = kmap_atomic(page);
649 memset(kaddr, 0, chunk_size);
650 de = (struct ext2_dir_entry_2 *)kaddr;
651 de->name_len = 1;
652 de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1));
653 memcpy (de->name, ".\0\0", 4);
654 de->inode = cpu_to_le32(inode->i_ino);
655 ext2_set_de_type (de, inode);
656
657 de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1));
658 de->name_len = 2;
659 de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1));
660 de->inode = cpu_to_le32(parent->i_ino);
661 memcpy (de->name, "..\0", 4);
662 ext2_set_de_type (de, inode);
663 kunmap_atomic(kaddr);
664 err = ext2_commit_chunk(page, 0, chunk_size);
665 fail:
666 page_cache_release(page);
667 return err;
668 }
669
670 /*
671 * routine to check that the specified directory is empty (for rmdir)
672 */
673 int ext2_empty_dir (struct inode * inode)
674 {
675 struct page *page = NULL;
676 unsigned long i, npages = dir_pages(inode);
677 int dir_has_error = 0;
678
679 for (i = 0; i < npages; i++) {
680 char *kaddr;
681 ext2_dirent * de;
682 page = ext2_get_page(inode, i, dir_has_error);
683
684 if (IS_ERR(page)) {
685 dir_has_error = 1;
686 continue;
687 }
688
689 kaddr = page_address(page);
690 de = (ext2_dirent *)kaddr;
691 kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1);
692
693 while ((char *)de <= kaddr) {
694 if (de->rec_len == 0) {
695 ext2_error(inode->i_sb, __func__,
696 "zero-length directory entry");
697 printk("kaddr=%p, de=%p\n", kaddr, de);
698 goto not_empty;
699 }
700 if (de->inode != 0) {
701 /* check for . and .. */
702 if (de->name[0] != '.')
703 goto not_empty;
704 if (de->name_len > 2)
705 goto not_empty;
706 if (de->name_len < 2) {
707 if (de->inode !=
708 cpu_to_le32(inode->i_ino))
709 goto not_empty;
710 } else if (de->name[1] != '.')
711 goto not_empty;
712 }
713 de = ext2_next_entry(de);
714 }
715 ext2_put_page(page);
716 }
717 return 1;
718
719 not_empty:
720 ext2_put_page(page);
721 return 0;
722 }
723
724 const struct file_operations ext2_dir_operations = {
725 .llseek = generic_file_llseek,
726 .read = generic_read_dir,
727 .readdir = ext2_readdir,
728 .unlocked_ioctl = ext2_ioctl,
729 #ifdef CONFIG_COMPAT
730 .compat_ioctl = ext2_compat_ioctl,
731 #endif
732 .fsync = ext2_fsync,
733 };
kernel source for telekom puls (alcatel/mediatek)