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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/ext2/dir.c
4 *
5 * Copyright (C) 1992, 1993, 1994, 1995
6 * Remy Card ([email protected])
7 * Laboratoire MASI - Institut Blaise Pascal
8 * Universite Pierre et Marie Curie (Paris VI)
9 *
10 * from
11 *
12 * linux/fs/minix/dir.c
13 *
14 * Copyright (C) 1991, 1992 Linus Torvalds
15 *
16 * ext2 directory handling functions
17 *
18 * Big-endian to little-endian byte-swapping/bitmaps by
19 * David S. Miller ([email protected]), 1995
20 *
21 * All code that works with directory layout had been switched to pagecache
22 * and moved here. AV
23 */
24
25#include "ext2.h"
26#include <linux/buffer_head.h>
27#include <linux/filelock.h>
28#include <linux/pagemap.h>
29#include <linux/swap.h>
30#include <linux/iversion.h>
31
32typedef struct ext2_dir_entry_2 ext2_dirent;
33
34/*
35 * Tests against MAX_REC_LEN etc were put in place for 64k block
36 * sizes; if that is not possible on this arch, we can skip
37 * those tests and speed things up.
38 */
39static inline unsigned ext2_rec_len_from_disk(__le16 dlen)
40{
41 unsigned len = le16_to_cpu(dlen);
42
43#if (PAGE_SIZE >= 65536)
44 if (len == EXT2_MAX_REC_LEN)
45 return 1 << 16;
46#endif
47 return len;
48}
49
50static inline __le16 ext2_rec_len_to_disk(unsigned len)
51{
52#if (PAGE_SIZE >= 65536)
53 if (len == (1 << 16))
54 return cpu_to_le16(EXT2_MAX_REC_LEN);
55 else
56 BUG_ON(len > (1 << 16));
57#endif
58 return cpu_to_le16(len);
59}
60
61/*
62 * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
63 * more robust, but we have what we have
64 */
65static inline unsigned ext2_chunk_size(struct inode *inode)
66{
67 return inode->i_sb->s_blocksize;
68}
69
70/*
71 * Return the offset into page `page_nr' of the last valid
72 * byte in that page, plus one.
73 */
74static unsigned
75ext2_last_byte(struct inode *inode, unsigned long page_nr)
76{
77 unsigned last_byte = inode->i_size;
78
79 last_byte -= page_nr << PAGE_SHIFT;
80 if (last_byte > PAGE_SIZE)
81 last_byte = PAGE_SIZE;
82 return last_byte;
83}
84
85static void ext2_commit_chunk(struct folio *folio, loff_t pos, unsigned len)
86{
87 struct address_space *mapping = folio->mapping;
88 struct inode *dir = mapping->host;
89
90 inode_inc_iversion(dir);
91 block_write_end(pos, len, len, folio);
92
93 if (pos+len > dir->i_size) {
94 i_size_write(dir, pos+len);
95 mark_inode_dirty(dir);
96 }
97 folio_unlock(folio);
98}
99
100static bool ext2_check_folio(struct folio *folio, int quiet, char *kaddr)
101{
102 struct inode *dir = folio->mapping->host;
103 struct super_block *sb = dir->i_sb;
104 unsigned chunk_size = ext2_chunk_size(dir);
105 u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
106 unsigned offs, rec_len;
107 unsigned limit = folio_size(folio);
108 ext2_dirent *p;
109 char *error;
110
111 if (dir->i_size < folio_pos(folio) + limit) {
112 limit = offset_in_folio(folio, dir->i_size);
113 if (limit & (chunk_size - 1))
114 goto Ebadsize;
115 if (!limit)
116 goto out;
117 }
118 for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
119 p = (ext2_dirent *)(kaddr + offs);
120 rec_len = ext2_rec_len_from_disk(p->rec_len);
121
122 if (unlikely(rec_len < EXT2_DIR_REC_LEN(1)))
123 goto Eshort;
124 if (unlikely(rec_len & 3))
125 goto Ealign;
126 if (unlikely(rec_len < EXT2_DIR_REC_LEN(p->name_len)))
127 goto Enamelen;
128 if (unlikely(((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)))
129 goto Espan;
130 if (unlikely(le32_to_cpu(p->inode) > max_inumber))
131 goto Einumber;
132 }
133 if (offs != limit)
134 goto Eend;
135out:
136 folio_set_checked(folio);
137 return true;
138
139 /* Too bad, we had an error */
140
141Ebadsize:
142 if (!quiet)
143 ext2_error(sb, __func__,
144 "size of directory #%llu is not a multiple "
145 "of chunk size", dir->i_ino);
146 goto fail;
147Eshort:
148 error = "rec_len is smaller than minimal";
149 goto bad_entry;
150Ealign:
151 error = "unaligned directory entry";
152 goto bad_entry;
153Enamelen:
154 error = "rec_len is too small for name_len";
155 goto bad_entry;
156Espan:
157 error = "directory entry across blocks";
158 goto bad_entry;
159Einumber:
160 error = "inode out of bounds";
161bad_entry:
162 if (!quiet)
163 ext2_error(sb, __func__, "bad entry in directory #%llu: : %s - "
164 "offset=%llu, inode=%lu, rec_len=%d, name_len=%d",
165 dir->i_ino, error, folio_pos(folio) + offs,
166 (unsigned long) le32_to_cpu(p->inode),
167 rec_len, p->name_len);
168 goto fail;
169Eend:
170 if (!quiet) {
171 p = (ext2_dirent *)(kaddr + offs);
172 ext2_error(sb, "ext2_check_folio",
173 "entry in directory #%llu spans the page boundary"
174 "offset=%llu, inode=%lu",
175 dir->i_ino, folio_pos(folio) + offs,
176 (unsigned long) le32_to_cpu(p->inode));
177 }
178fail:
179 return false;
180}
181
182/*
183 * Calls to ext2_get_folio()/folio_release_kmap() must be nested according
184 * to the rules documented in kmap_local_folio()/kunmap_local().
185 *
186 * NOTE: ext2_find_entry() and ext2_dotdot() act as a call
187 * to folio_release_kmap() and should be treated as a call to
188 * folio_release_kmap() for nesting purposes.
189 */
190static void *ext2_get_folio(struct inode *dir, unsigned long n,
191 int quiet, struct folio **foliop)
192{
193 struct address_space *mapping = dir->i_mapping;
194 struct folio *folio = read_mapping_folio(mapping, n, NULL);
195 void *kaddr;
196
197 if (IS_ERR(folio))
198 return ERR_CAST(folio);
199 kaddr = kmap_local_folio(folio, 0);
200 if (unlikely(!folio_test_checked(folio))) {
201 if (!ext2_check_folio(folio, quiet, kaddr))
202 goto fail;
203 }
204 *foliop = folio;
205 return kaddr;
206
207fail:
208 folio_release_kmap(folio, kaddr);
209 return ERR_PTR(-EIO);
210}
211
212/*
213 * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
214 *
215 * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
216 */
217static inline int ext2_match (int len, const char * const name,
218 struct ext2_dir_entry_2 * de)
219{
220 if (len != de->name_len)
221 return 0;
222 if (!de->inode)
223 return 0;
224 return !memcmp(name, de->name, len);
225}
226
227/*
228 * p is at least 6 bytes before the end of page
229 */
230static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
231{
232 return (ext2_dirent *)((char *)p +
233 ext2_rec_len_from_disk(p->rec_len));
234}
235
236static inline unsigned
237ext2_validate_entry(char *base, unsigned offset, unsigned mask)
238{
239 ext2_dirent *de = (ext2_dirent*)(base + offset);
240 ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
241 while ((char*)p < (char*)de) {
242 if (p->rec_len == 0)
243 break;
244 p = ext2_next_entry(p);
245 }
246 return offset_in_page(p);
247}
248
249static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
250{
251 if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
252 de->file_type = fs_umode_to_ftype(inode->i_mode);
253 else
254 de->file_type = 0;
255}
256
257static int
258ext2_readdir(struct file *file, struct dir_context *ctx)
259{
260 loff_t pos = ctx->pos;
261 struct inode *inode = file_inode(file);
262 struct super_block *sb = inode->i_sb;
263 unsigned int offset = pos & ~PAGE_MASK;
264 unsigned long n = pos >> PAGE_SHIFT;
265 unsigned long npages = dir_pages(inode);
266 unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
267 bool need_revalidate = !inode_eq_iversion(inode, *(u64 *)file->private_data);
268 bool has_filetype;
269
270 if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
271 return 0;
272
273 has_filetype =
274 EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE);
275
276 for ( ; n < npages; n++, offset = 0) {
277 ext2_dirent *de;
278 struct folio *folio;
279 char *kaddr = ext2_get_folio(inode, n, 0, &folio);
280 char *limit;
281
282 if (IS_ERR(kaddr)) {
283 ext2_error(sb, __func__,
284 "bad page in #%llu",
285 inode->i_ino);
286 ctx->pos += PAGE_SIZE - offset;
287 return PTR_ERR(kaddr);
288 }
289 if (unlikely(need_revalidate)) {
290 if (offset) {
291 offset = ext2_validate_entry(kaddr, offset, chunk_mask);
292 ctx->pos = (n<<PAGE_SHIFT) + offset;
293 }
294 *(u64 *)file->private_data = inode_query_iversion(inode);
295 need_revalidate = false;
296 }
297 de = (ext2_dirent *)(kaddr+offset);
298 limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1);
299 for ( ;(char*)de <= limit; de = ext2_next_entry(de)) {
300 if (de->rec_len == 0) {
301 ext2_error(sb, __func__,
302 "zero-length directory entry");
303 folio_release_kmap(folio, de);
304 return -EIO;
305 }
306 if (de->inode) {
307 unsigned char d_type = DT_UNKNOWN;
308
309 if (has_filetype)
310 d_type = fs_ftype_to_dtype(de->file_type);
311
312 if (!dir_emit(ctx, de->name, de->name_len,
313 le32_to_cpu(de->inode),
314 d_type)) {
315 folio_release_kmap(folio, de);
316 return 0;
317 }
318 }
319 ctx->pos += ext2_rec_len_from_disk(de->rec_len);
320 }
321 folio_release_kmap(folio, kaddr);
322 }
323 return 0;
324}
325
326/*
327 * ext2_find_entry()
328 *
329 * finds an entry in the specified directory with the wanted name. It
330 * returns the page in which the entry was found (as a parameter - res_page),
331 * and the entry itself. Page is returned mapped and unlocked.
332 * Entry is guaranteed to be valid.
333 *
334 * On Success folio_release_kmap() should be called on *foliop.
335 *
336 * NOTE: Calls to ext2_get_folio()/folio_release_kmap() must be nested
337 * according to the rules documented in kmap_local_folio()/kunmap_local().
338 *
339 * ext2_find_entry() and ext2_dotdot() act as a call to ext2_get_folio()
340 * and should be treated as a call to ext2_get_folio() for nesting
341 * purposes.
342 */
343struct ext2_dir_entry_2 *ext2_find_entry (struct inode *dir,
344 const struct qstr *child, struct folio **foliop)
345{
346 const char *name = child->name;
347 int namelen = child->len;
348 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
349 unsigned long start, n;
350 unsigned long npages = dir_pages(dir);
351 struct ext2_inode_info *ei = EXT2_I(dir);
352 ext2_dirent * de;
353
354 if (npages == 0)
355 goto out;
356
357 start = ei->i_dir_start_lookup;
358 if (start >= npages)
359 start = 0;
360 n = start;
361 do {
362 char *kaddr = ext2_get_folio(dir, n, 0, foliop);
363 if (IS_ERR(kaddr))
364 return ERR_CAST(kaddr);
365
366 de = (ext2_dirent *) kaddr;
367 kaddr += ext2_last_byte(dir, n) - reclen;
368 while ((char *) de <= kaddr) {
369 if (de->rec_len == 0) {
370 ext2_error(dir->i_sb, __func__,
371 "zero-length directory entry");
372 folio_release_kmap(*foliop, de);
373 goto out;
374 }
375 if (ext2_match(namelen, name, de))
376 goto found;
377 de = ext2_next_entry(de);
378 }
379 folio_release_kmap(*foliop, kaddr);
380
381 if (++n >= npages)
382 n = 0;
383 /* next folio is past the blocks we've got */
384 if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
385 ext2_error(dir->i_sb, __func__,
386 "dir %llu size %lld exceeds block count %llu",
387 dir->i_ino, dir->i_size,
388 (unsigned long long)dir->i_blocks);
389 goto out;
390 }
391 } while (n != start);
392out:
393 return ERR_PTR(-ENOENT);
394
395found:
396 ei->i_dir_start_lookup = n;
397 return de;
398}
399
400/*
401 * Return the '..' directory entry and the page in which the entry was found
402 * (as a parameter - p).
403 *
404 * On Success folio_release_kmap() should be called on *foliop.
405 *
406 * NOTE: Calls to ext2_get_folio()/folio_release_kmap() must be nested
407 * according to the rules documented in kmap_local_folio()/kunmap_local().
408 *
409 * ext2_find_entry() and ext2_dotdot() act as a call to ext2_get_folio()
410 * and should be treated as a call to ext2_get_folio() for nesting
411 * purposes.
412 */
413struct ext2_dir_entry_2 *ext2_dotdot(struct inode *dir, struct folio **foliop)
414{
415 ext2_dirent *de = ext2_get_folio(dir, 0, 0, foliop);
416
417 if (!IS_ERR(de))
418 return ext2_next_entry(de);
419 return NULL;
420}
421
422int ext2_inode_by_name(struct inode *dir, const struct qstr *child, ino_t *ino)
423{
424 struct ext2_dir_entry_2 *de;
425 struct folio *folio;
426
427 de = ext2_find_entry(dir, child, &folio);
428 if (IS_ERR(de))
429 return PTR_ERR(de);
430
431 *ino = le32_to_cpu(de->inode);
432 folio_release_kmap(folio, de);
433 return 0;
434}
435
436static int ext2_prepare_chunk(struct folio *folio, loff_t pos, unsigned len)
437{
438 return __block_write_begin(folio, pos, len, ext2_get_block);
439}
440
441static int ext2_handle_dirsync(struct inode *dir)
442{
443 int err;
444
445 err = filemap_write_and_wait(dir->i_mapping);
446 if (!err)
447 err = sync_inode_metadata(dir, 1);
448 return err;
449}
450
451int ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
452 struct folio *folio, struct inode *inode, bool update_times)
453{
454 loff_t pos = folio_pos(folio) + offset_in_folio(folio, de);
455 unsigned len = ext2_rec_len_from_disk(de->rec_len);
456 int err;
457
458 folio_lock(folio);
459 err = ext2_prepare_chunk(folio, pos, len);
460 if (err) {
461 folio_unlock(folio);
462 return err;
463 }
464 de->inode = cpu_to_le32(inode->i_ino);
465 ext2_set_de_type(de, inode);
466 ext2_commit_chunk(folio, pos, len);
467 if (update_times)
468 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
469 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
470 mark_inode_dirty(dir);
471 return ext2_handle_dirsync(dir);
472}
473
474/*
475 * Parent is locked.
476 */
477int ext2_add_link (struct dentry *dentry, struct inode *inode)
478{
479 struct inode *dir = d_inode(dentry->d_parent);
480 const char *name = dentry->d_name.name;
481 int namelen = dentry->d_name.len;
482 unsigned chunk_size = ext2_chunk_size(dir);
483 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
484 unsigned short rec_len, name_len;
485 struct folio *folio = NULL;
486 ext2_dirent * de;
487 unsigned long npages = dir_pages(dir);
488 unsigned long n;
489 loff_t pos;
490 int err;
491
492 /*
493 * We take care of directory expansion in the same loop.
494 * This code plays outside i_size, so it locks the folio
495 * to protect that region.
496 */
497 for (n = 0; n <= npages; n++) {
498 char *kaddr = ext2_get_folio(dir, n, 0, &folio);
499 char *dir_end;
500
501 if (IS_ERR(kaddr))
502 return PTR_ERR(kaddr);
503 folio_lock(folio);
504 dir_end = kaddr + ext2_last_byte(dir, n);
505 de = (ext2_dirent *)kaddr;
506 kaddr += folio_size(folio) - reclen;
507 while ((char *)de <= kaddr) {
508 if ((char *)de == dir_end) {
509 /* We hit i_size */
510 name_len = 0;
511 rec_len = chunk_size;
512 de->rec_len = ext2_rec_len_to_disk(chunk_size);
513 de->inode = 0;
514 goto got_it;
515 }
516 if (de->rec_len == 0) {
517 ext2_error(dir->i_sb, __func__,
518 "zero-length directory entry");
519 err = -EIO;
520 goto out_unlock;
521 }
522 err = -EEXIST;
523 if (ext2_match (namelen, name, de))
524 goto out_unlock;
525 name_len = EXT2_DIR_REC_LEN(de->name_len);
526 rec_len = ext2_rec_len_from_disk(de->rec_len);
527 if (!de->inode && rec_len >= reclen)
528 goto got_it;
529 if (rec_len >= name_len + reclen)
530 goto got_it;
531 de = (ext2_dirent *) ((char *) de + rec_len);
532 }
533 folio_unlock(folio);
534 folio_release_kmap(folio, kaddr);
535 }
536 BUG();
537 return -EINVAL;
538
539got_it:
540 pos = folio_pos(folio) + offset_in_folio(folio, de);
541 err = ext2_prepare_chunk(folio, pos, rec_len);
542 if (err)
543 goto out_unlock;
544 if (de->inode) {
545 ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
546 de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len);
547 de->rec_len = ext2_rec_len_to_disk(name_len);
548 de = de1;
549 }
550 de->name_len = namelen;
551 memcpy(de->name, name, namelen);
552 de->inode = cpu_to_le32(inode->i_ino);
553 ext2_set_de_type (de, inode);
554 ext2_commit_chunk(folio, pos, rec_len);
555 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
556 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
557 mark_inode_dirty(dir);
558 err = ext2_handle_dirsync(dir);
559 /* OFFSET_CACHE */
560out_put:
561 folio_release_kmap(folio, de);
562 return err;
563out_unlock:
564 folio_unlock(folio);
565 goto out_put;
566}
567
568/*
569 * ext2_delete_entry deletes a directory entry by merging it with the
570 * previous entry. Page is up-to-date.
571 */
572int ext2_delete_entry(struct ext2_dir_entry_2 *dir, struct folio *folio)
573{
574 struct inode *inode = folio->mapping->host;
575 size_t from, to;
576 char *kaddr;
577 loff_t pos;
578 ext2_dirent *de, *pde = NULL;
579 int err;
580
581 from = offset_in_folio(folio, dir);
582 to = from + ext2_rec_len_from_disk(dir->rec_len);
583 kaddr = (char *)dir - from;
584 from &= ~(ext2_chunk_size(inode)-1);
585 de = (ext2_dirent *)(kaddr + from);
586
587 while ((char*)de < (char*)dir) {
588 if (de->rec_len == 0) {
589 ext2_error(inode->i_sb, __func__,
590 "zero-length directory entry");
591 return -EIO;
592 }
593 pde = de;
594 de = ext2_next_entry(de);
595 }
596 if (pde)
597 from = offset_in_folio(folio, pde);
598 pos = folio_pos(folio) + from;
599 folio_lock(folio);
600 err = ext2_prepare_chunk(folio, pos, to - from);
601 if (err) {
602 folio_unlock(folio);
603 return err;
604 }
605 if (pde)
606 pde->rec_len = ext2_rec_len_to_disk(to - from);
607 dir->inode = 0;
608 ext2_commit_chunk(folio, pos, to - from);
609 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
610 EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL;
611 mark_inode_dirty(inode);
612 return ext2_handle_dirsync(inode);
613}
614
615/*
616 * Set the first fragment of directory.
617 */
618int ext2_make_empty(struct inode *inode, struct inode *parent)
619{
620 struct folio *folio = filemap_grab_folio(inode->i_mapping, 0);
621 unsigned chunk_size = ext2_chunk_size(inode);
622 struct ext2_dir_entry_2 * de;
623 int err;
624 void *kaddr;
625
626 if (IS_ERR(folio))
627 return PTR_ERR(folio);
628
629 err = ext2_prepare_chunk(folio, 0, chunk_size);
630 if (err) {
631 folio_unlock(folio);
632 goto fail;
633 }
634 kaddr = kmap_local_folio(folio, 0);
635 memset(kaddr, 0, chunk_size);
636 de = (struct ext2_dir_entry_2 *)kaddr;
637 de->name_len = 1;
638 de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1));
639 memcpy (de->name, ".\0\0", 4);
640 de->inode = cpu_to_le32(inode->i_ino);
641 ext2_set_de_type (de, inode);
642
643 de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1));
644 de->name_len = 2;
645 de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1));
646 de->inode = cpu_to_le32(parent->i_ino);
647 memcpy (de->name, "..\0", 4);
648 ext2_set_de_type (de, inode);
649 kunmap_local(kaddr);
650 ext2_commit_chunk(folio, 0, chunk_size);
651 err = ext2_handle_dirsync(inode);
652fail:
653 folio_put(folio);
654 return err;
655}
656
657/*
658 * routine to check that the specified directory is empty (for rmdir)
659 */
660int ext2_empty_dir(struct inode *inode)
661{
662 struct folio *folio;
663 char *kaddr;
664 unsigned long i, npages = dir_pages(inode);
665
666 for (i = 0; i < npages; i++) {
667 ext2_dirent *de;
668
669 kaddr = ext2_get_folio(inode, i, 0, &folio);
670 if (IS_ERR(kaddr))
671 return 0;
672
673 de = (ext2_dirent *)kaddr;
674 kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1);
675
676 while ((char *)de <= kaddr) {
677 if (de->rec_len == 0) {
678 ext2_error(inode->i_sb, __func__,
679 "zero-length directory entry");
680 printk("kaddr=%p, de=%p\n", kaddr, de);
681 goto not_empty;
682 }
683 if (de->inode != 0) {
684 /* check for . and .. */
685 if (de->name[0] != '.')
686 goto not_empty;
687 if (de->name_len > 2)
688 goto not_empty;
689 if (de->name_len < 2) {
690 if (de->inode !=
691 cpu_to_le32(inode->i_ino))
692 goto not_empty;
693 } else if (de->name[1] != '.')
694 goto not_empty;
695 }
696 de = ext2_next_entry(de);
697 }
698 folio_release_kmap(folio, kaddr);
699 }
700 return 1;
701
702not_empty:
703 folio_release_kmap(folio, kaddr);
704 return 0;
705}
706
707static int ext2_dir_open(struct inode *inode, struct file *file)
708{
709 file->private_data = kzalloc(sizeof(u64), GFP_KERNEL);
710 if (!file->private_data)
711 return -ENOMEM;
712 return 0;
713}
714
715static int ext2_dir_release(struct inode *inode, struct file *file)
716{
717 kfree(file->private_data);
718 return 0;
719}
720
721static loff_t ext2_dir_llseek(struct file *file, loff_t offset, int whence)
722{
723 return generic_llseek_cookie(file, offset, whence,
724 (u64 *)file->private_data);
725}
726
727const struct file_operations ext2_dir_operations = {
728 .open = ext2_dir_open,
729 .release = ext2_dir_release,
730 .llseek = ext2_dir_llseek,
731 .read = generic_read_dir,
732 .iterate_shared = ext2_readdir,
733 .unlocked_ioctl = ext2_ioctl,
734#ifdef CONFIG_COMPAT
735 .compat_ioctl = ext2_compat_ioctl,
736#endif
737 .fsync = simple_fsync,
738 .setlease = generic_setlease,
739};