1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/ext4/dir.c
4 *
5 * Copyright (C) 1992, 1993, 1994, 1995
6 * Remy Card (card@masi.ibp.fr)
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 * ext4 directory handling functions
17 *
18 * Big-endian to little-endian byte-swapping/bitmaps by
19 * David S. Miller (davem@caip.rutgers.edu), 1995
20 *
21 * Hash Tree Directory indexing (c) 2001 Daniel Phillips
22 *
23 */
24
25 #include <linux/fs.h>
26 #include <linux/buffer_head.h>
27 #include <linux/slab.h>
28 #include <linux/iversion.h>
29 #include <linux/unicode.h>
30 #include "ext4.h"
31 #include "xattr.h"
32
33 static int ext4_dx_readdir(struct file *, struct dir_context *);
34
35 /**
36 * is_dx_dir() - check if a directory is using htree indexing
37 * @inode: directory inode
38 *
39 * Check if the given dir-inode refers to an htree-indexed directory
40 * (or a directory which could potentially get converted to use htree
41 * indexing).
42 *
43 * Return 1 if it is a dx dir, 0 if not
44 */
is_dx_dir(struct inode * inode)45 static int is_dx_dir(struct inode *inode)
46 {
47 struct super_block *sb = inode->i_sb;
48
49 if (ext4_has_feature_dir_index(inode->i_sb) &&
50 ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
51 ((inode->i_size >> sb->s_blocksize_bits) == 1) ||
52 ext4_has_inline_data(inode)))
53 return 1;
54
55 return 0;
56 }
57
is_fake_dir_entry(struct ext4_dir_entry_2 * de)58 static bool is_fake_dir_entry(struct ext4_dir_entry_2 *de)
59 {
60 /* Check if . or .. , or skip if namelen is 0 */
61 if ((de->name_len > 0) && (de->name_len <= 2) && (de->name[0] == '.') &&
62 (de->name[1] == '.' || de->name[1] == '\0'))
63 return true;
64 /* Check if this is a csum entry */
65 if (de->file_type == EXT4_FT_DIR_CSUM)
66 return true;
67 return false;
68 }
69
70 /*
71 * Return 0 if the directory entry is OK, and 1 if there is a problem
72 *
73 * Note: this is the opposite of what ext2 and ext3 historically returned...
74 *
75 * bh passed here can be an inode block or a dir data block, depending
76 * on the inode inline data flag.
77 */
__ext4_check_dir_entry(const char * function,unsigned int line,struct inode * dir,struct file * filp,struct ext4_dir_entry_2 * de,struct buffer_head * bh,char * buf,int size,unsigned int offset)78 int __ext4_check_dir_entry(const char *function, unsigned int line,
79 struct inode *dir, struct file *filp,
80 struct ext4_dir_entry_2 *de,
81 struct buffer_head *bh, char *buf, int size,
82 unsigned int offset)
83 {
84 const char *error_msg = NULL;
85 const int rlen = ext4_rec_len_from_disk(de->rec_len,
86 dir->i_sb->s_blocksize);
87 const int next_offset = ((char *) de - buf) + rlen;
88 bool fake = is_fake_dir_entry(de);
89 bool has_csum = ext4_has_metadata_csum(dir->i_sb);
90
91 if (unlikely(rlen < ext4_dir_rec_len(1, fake ? NULL : dir)))
92 error_msg = "rec_len is smaller than minimal";
93 else if (unlikely(rlen % 4 != 0))
94 error_msg = "rec_len % 4 != 0";
95 else if (unlikely(rlen < ext4_dir_rec_len(de->name_len,
96 fake ? NULL : dir)))
97 error_msg = "rec_len is too small for name_len";
98 else if (unlikely(next_offset > size))
99 error_msg = "directory entry overrun";
100 else if (unlikely(next_offset > size - ext4_dir_rec_len(1,
101 has_csum ? NULL : dir) &&
102 next_offset != size))
103 error_msg = "directory entry too close to block end";
104 else if (unlikely(le32_to_cpu(de->inode) >
105 le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
106 error_msg = "inode out of bounds";
107 else
108 return 0;
109
110 if (filp)
111 ext4_error_file(filp, function, line, bh->b_blocknr,
112 "bad entry in directory: %s - offset=%u, "
113 "inode=%u, rec_len=%d, size=%d fake=%d",
114 error_msg, offset, le32_to_cpu(de->inode),
115 rlen, size, fake);
116 else
117 ext4_error_inode(dir, function, line, bh->b_blocknr,
118 "bad entry in directory: %s - offset=%u, "
119 "inode=%u, rec_len=%d, size=%d fake=%d",
120 error_msg, offset, le32_to_cpu(de->inode),
121 rlen, size, fake);
122
123 return 1;
124 }
125
ext4_readdir(struct file * file,struct dir_context * ctx)126 static int ext4_readdir(struct file *file, struct dir_context *ctx)
127 {
128 unsigned int offset;
129 int i;
130 struct ext4_dir_entry_2 *de;
131 int err;
132 struct inode *inode = file_inode(file);
133 struct super_block *sb = inode->i_sb;
134 struct buffer_head *bh = NULL;
135 struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
136 struct dir_private_info *info = file->private_data;
137
138 err = fscrypt_prepare_readdir(inode);
139 if (err)
140 return err;
141
142 if (is_dx_dir(inode)) {
143 err = ext4_dx_readdir(file, ctx);
144 if (err != ERR_BAD_DX_DIR)
145 return err;
146
147 /* Can we just clear INDEX flag to ignore htree information? */
148 if (!ext4_has_metadata_csum(sb)) {
149 /*
150 * We don't set the inode dirty flag since it's not
151 * critical that it gets flushed back to the disk.
152 */
153 ext4_clear_inode_flag(inode, EXT4_INODE_INDEX);
154 }
155 }
156
157 if (ext4_has_inline_data(inode)) {
158 int has_inline_data = 1;
159 err = ext4_read_inline_dir(file, ctx,
160 &has_inline_data);
161 if (has_inline_data)
162 return err;
163 }
164
165 if (IS_ENCRYPTED(inode)) {
166 err = fscrypt_fname_alloc_buffer(EXT4_NAME_LEN, &fstr);
167 if (err < 0)
168 return err;
169 }
170
171 while (ctx->pos < inode->i_size) {
172 struct ext4_map_blocks map;
173
174 if (fatal_signal_pending(current)) {
175 err = -ERESTARTSYS;
176 goto errout;
177 }
178 cond_resched();
179 offset = ctx->pos & (sb->s_blocksize - 1);
180 map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
181 map.m_len = 1;
182 err = ext4_map_blocks(NULL, inode, &map, 0);
183 if (err == 0) {
184 /* m_len should never be zero but let's avoid
185 * an infinite loop if it somehow is */
186 if (map.m_len == 0)
187 map.m_len = 1;
188 ctx->pos += map.m_len * sb->s_blocksize;
189 continue;
190 }
191 if (err > 0) {
192 pgoff_t index = map.m_pblk >>
193 (PAGE_SHIFT - inode->i_blkbits);
194 if (!ra_has_index(&file->f_ra, index))
195 page_cache_sync_readahead(
196 sb->s_bdev->bd_mapping,
197 &file->f_ra, file,
198 index, 1);
199 file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
200 bh = ext4_bread(NULL, inode, map.m_lblk, 0);
201 if (IS_ERR(bh)) {
202 err = PTR_ERR(bh);
203 bh = NULL;
204 goto errout;
205 }
206 }
207
208 if (!bh) {
209 /* corrupt size? Maybe no more blocks to read */
210 if (ctx->pos > inode->i_blocks << 9)
211 break;
212 ctx->pos += sb->s_blocksize - offset;
213 continue;
214 }
215
216 /* Check the checksum */
217 if (!buffer_verified(bh) &&
218 !ext4_dirblock_csum_verify(inode, bh)) {
219 EXT4_ERROR_FILE(file, 0, "directory fails checksum "
220 "at offset %llu",
221 (unsigned long long)ctx->pos);
222 ctx->pos += sb->s_blocksize - offset;
223 brelse(bh);
224 bh = NULL;
225 continue;
226 }
227 set_buffer_verified(bh);
228
229 /* If the dir block has changed since the last call to
230 * readdir(2), then we might be pointing to an invalid
231 * dirent right now. Scan from the start of the block
232 * to make sure. */
233 if (!inode_eq_iversion(inode, info->cookie)) {
234 for (i = 0; i < sb->s_blocksize && i < offset; ) {
235 de = (struct ext4_dir_entry_2 *)
236 (bh->b_data + i);
237 /* It's too expensive to do a full
238 * dirent test each time round this
239 * loop, but we do have to test at
240 * least that it is non-zero. A
241 * failure will be detected in the
242 * dirent test below. */
243 if (ext4_rec_len_from_disk(de->rec_len,
244 sb->s_blocksize) < ext4_dir_rec_len(1,
245 inode))
246 break;
247 i += ext4_rec_len_from_disk(de->rec_len,
248 sb->s_blocksize);
249 }
250 offset = i;
251 ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
252 | offset;
253 info->cookie = inode_query_iversion(inode);
254 }
255
256 while (ctx->pos < inode->i_size
257 && offset < sb->s_blocksize) {
258 de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
259 if (ext4_check_dir_entry(inode, file, de, bh,
260 bh->b_data, bh->b_size,
261 offset)) {
262 /*
263 * On error, skip to the next block
264 */
265 ctx->pos = (ctx->pos |
266 (sb->s_blocksize - 1)) + 1;
267 break;
268 }
269 offset += ext4_rec_len_from_disk(de->rec_len,
270 sb->s_blocksize);
271 if (le32_to_cpu(de->inode)) {
272 if (!IS_ENCRYPTED(inode)) {
273 if (!dir_emit(ctx, de->name,
274 de->name_len,
275 le32_to_cpu(de->inode),
276 get_dtype(sb, de->file_type)))
277 goto done;
278 } else {
279 int save_len = fstr.len;
280 struct fscrypt_str de_name =
281 FSTR_INIT(de->name,
282 de->name_len);
283 u32 hash;
284 u32 minor_hash;
285
286 if (IS_CASEFOLDED(inode)) {
287 hash = EXT4_DIRENT_HASH(de);
288 minor_hash = EXT4_DIRENT_MINOR_HASH(de);
289 } else {
290 hash = 0;
291 minor_hash = 0;
292 }
293
294 /* Directory is encrypted */
295 err = fscrypt_fname_disk_to_usr(inode,
296 hash, minor_hash, &de_name, &fstr);
297 de_name = fstr;
298 fstr.len = save_len;
299 if (err)
300 goto errout;
301 if (!dir_emit(ctx,
302 de_name.name, de_name.len,
303 le32_to_cpu(de->inode),
304 get_dtype(sb, de->file_type)))
305 goto done;
306 }
307 }
308 ctx->pos += ext4_rec_len_from_disk(de->rec_len,
309 sb->s_blocksize);
310 }
311 if ((ctx->pos < inode->i_size) && !dir_relax_shared(inode))
312 goto done;
313 brelse(bh);
314 bh = NULL;
315 }
316 done:
317 err = 0;
318 errout:
319 fscrypt_fname_free_buffer(&fstr);
320 brelse(bh);
321 return err;
322 }
323
is_32bit_api(void)324 static inline int is_32bit_api(void)
325 {
326 #ifdef CONFIG_COMPAT
327 return in_compat_syscall();
328 #else
329 return (BITS_PER_LONG == 32);
330 #endif
331 }
332
333 /*
334 * These functions convert from the major/minor hash to an f_pos
335 * value for dx directories
336 *
337 * Upper layer (for example NFS) should specify FMODE_32BITHASH or
338 * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
339 * directly on both 32-bit and 64-bit nodes, under such case, neither
340 * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
341 */
hash2pos(struct file * filp,__u32 major,__u32 minor)342 static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
343 {
344 if ((filp->f_mode & FMODE_32BITHASH) ||
345 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
346 return major >> 1;
347 else
348 return ((__u64)(major >> 1) << 32) | (__u64)minor;
349 }
350
pos2maj_hash(struct file * filp,loff_t pos)351 static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
352 {
353 if ((filp->f_mode & FMODE_32BITHASH) ||
354 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
355 return (pos << 1) & 0xffffffff;
356 else
357 return ((pos >> 32) << 1) & 0xffffffff;
358 }
359
pos2min_hash(struct file * filp,loff_t pos)360 static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
361 {
362 if ((filp->f_mode & FMODE_32BITHASH) ||
363 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
364 return 0;
365 else
366 return pos & 0xffffffff;
367 }
368
369 /*
370 * Return 32- or 64-bit end-of-file for dx directories
371 */
ext4_get_htree_eof(struct file * filp)372 static inline loff_t ext4_get_htree_eof(struct file *filp)
373 {
374 if ((filp->f_mode & FMODE_32BITHASH) ||
375 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
376 return EXT4_HTREE_EOF_32BIT;
377 else
378 return EXT4_HTREE_EOF_64BIT;
379 }
380
381
382 /*
383 * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
384 * directories, where the "offset" is in terms of the filename hash
385 * value instead of the byte offset.
386 *
387 * Because we may return a 64-bit hash that is well beyond offset limits,
388 * we need to pass the max hash as the maximum allowable offset in
389 * the htree directory case.
390 *
391 * For non-htree, ext4_llseek already chooses the proper max offset.
392 */
ext4_dir_llseek(struct file * file,loff_t offset,int whence)393 static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
394 {
395 struct inode *inode = file->f_mapping->host;
396 struct dir_private_info *info = file->private_data;
397 int dx_dir = is_dx_dir(inode);
398 loff_t ret, htree_max = ext4_get_htree_eof(file);
399
400 if (likely(dx_dir))
401 ret = generic_file_llseek_size(file, offset, whence,
402 htree_max, htree_max);
403 else
404 ret = ext4_llseek(file, offset, whence);
405 info->cookie = inode_peek_iversion(inode) - 1;
406 return ret;
407 }
408
409 /*
410 * This structure holds the nodes of the red-black tree used to store
411 * the directory entry in hash order.
412 */
413 struct fname {
414 __u32 hash;
415 __u32 minor_hash;
416 struct rb_node rb_hash;
417 struct fname *next;
418 __u32 inode;
419 __u8 name_len;
420 __u8 file_type;
421 char name[] __counted_by(name_len);
422 };
423
424 /*
425 * This function implements a non-recursive way of freeing all of the
426 * nodes in the red-black tree.
427 */
free_rb_tree_fname(struct rb_root * root)428 static void free_rb_tree_fname(struct rb_root *root)
429 {
430 struct fname *fname, *next;
431
432 rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
433 while (fname) {
434 struct fname *old = fname;
435 fname = fname->next;
436 kfree(old);
437 }
438
439 *root = RB_ROOT;
440 }
441
ext4_htree_init_dir_info(struct file * filp,loff_t pos)442 static void ext4_htree_init_dir_info(struct file *filp, loff_t pos)
443 {
444 struct dir_private_info *p = filp->private_data;
445
446 if (is_dx_dir(file_inode(filp)) && !p->initialized) {
447 p->curr_hash = pos2maj_hash(filp, pos);
448 p->curr_minor_hash = pos2min_hash(filp, pos);
449 p->initialized = true;
450 }
451 }
452
ext4_htree_free_dir_info(struct dir_private_info * p)453 void ext4_htree_free_dir_info(struct dir_private_info *p)
454 {
455 free_rb_tree_fname(&p->root);
456 kfree(p);
457 }
458
459 /*
460 * Given a directory entry, enter it into the fname rb tree.
461 *
462 * When filename encryption is enabled, the dirent will hold the
463 * encrypted filename, while the htree will hold decrypted filename.
464 * The decrypted filename is passed in via ent_name. parameter.
465 */
ext4_htree_store_dirent(struct file * dir_file,__u32 hash,__u32 minor_hash,struct ext4_dir_entry_2 * dirent,struct fscrypt_str * ent_name)466 int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
467 __u32 minor_hash,
468 struct ext4_dir_entry_2 *dirent,
469 struct fscrypt_str *ent_name)
470 {
471 struct rb_node **p, *parent = NULL;
472 struct fname *fname, *new_fn;
473 struct dir_private_info *info;
474
475 info = dir_file->private_data;
476 p = &info->root.rb_node;
477
478 /* Create and allocate the fname structure */
479 new_fn = kzalloc(struct_size(new_fn, name, ent_name->len + 1),
480 GFP_KERNEL);
481 if (!new_fn)
482 return -ENOMEM;
483 new_fn->hash = hash;
484 new_fn->minor_hash = minor_hash;
485 new_fn->inode = le32_to_cpu(dirent->inode);
486 new_fn->name_len = ent_name->len;
487 new_fn->file_type = dirent->file_type;
488 memcpy(new_fn->name, ent_name->name, ent_name->len);
489
490 while (*p) {
491 parent = *p;
492 fname = rb_entry(parent, struct fname, rb_hash);
493
494 /*
495 * If the hash and minor hash match up, then we put
496 * them on a linked list. This rarely happens...
497 */
498 if ((new_fn->hash == fname->hash) &&
499 (new_fn->minor_hash == fname->minor_hash)) {
500 new_fn->next = fname->next;
501 fname->next = new_fn;
502 return 0;
503 }
504
505 if (new_fn->hash < fname->hash)
506 p = &(*p)->rb_left;
507 else if (new_fn->hash > fname->hash)
508 p = &(*p)->rb_right;
509 else if (new_fn->minor_hash < fname->minor_hash)
510 p = &(*p)->rb_left;
511 else /* if (new_fn->minor_hash > fname->minor_hash) */
512 p = &(*p)->rb_right;
513 }
514
515 rb_link_node(&new_fn->rb_hash, parent, p);
516 rb_insert_color(&new_fn->rb_hash, &info->root);
517 return 0;
518 }
519
520
521
522 /*
523 * This is a helper function for ext4_dx_readdir. It calls filldir
524 * for all entries on the fname linked list. (Normally there is only
525 * one entry on the linked list, unless there are 62 bit hash collisions.)
526 */
call_filldir(struct file * file,struct dir_context * ctx,struct fname * fname)527 static int call_filldir(struct file *file, struct dir_context *ctx,
528 struct fname *fname)
529 {
530 struct dir_private_info *info = file->private_data;
531 struct inode *inode = file_inode(file);
532 struct super_block *sb = inode->i_sb;
533
534 if (!fname) {
535 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
536 "called with null fname?!?", __func__, __LINE__,
537 inode->i_ino, current->comm);
538 return 0;
539 }
540 ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
541 while (fname) {
542 if (!dir_emit(ctx, fname->name,
543 fname->name_len,
544 fname->inode,
545 get_dtype(sb, fname->file_type))) {
546 info->extra_fname = fname;
547 return 1;
548 }
549 fname = fname->next;
550 }
551 return 0;
552 }
553
ext4_dx_readdir(struct file * file,struct dir_context * ctx)554 static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
555 {
556 struct dir_private_info *info = file->private_data;
557 struct inode *inode = file_inode(file);
558 struct fname *fname;
559 int ret = 0;
560
561 ext4_htree_init_dir_info(file, ctx->pos);
562
563 if (ctx->pos == ext4_get_htree_eof(file))
564 return 0; /* EOF */
565
566 /* Some one has messed with f_pos; reset the world */
567 if (info->last_pos != ctx->pos) {
568 free_rb_tree_fname(&info->root);
569 info->curr_node = NULL;
570 info->extra_fname = NULL;
571 info->curr_hash = pos2maj_hash(file, ctx->pos);
572 info->curr_minor_hash = pos2min_hash(file, ctx->pos);
573 }
574
575 /*
576 * If there are any leftover names on the hash collision
577 * chain, return them first.
578 */
579 if (info->extra_fname) {
580 if (call_filldir(file, ctx, info->extra_fname))
581 goto finished;
582 info->extra_fname = NULL;
583 goto next_node;
584 } else if (!info->curr_node)
585 info->curr_node = rb_first(&info->root);
586
587 while (1) {
588 /*
589 * Fill the rbtree if we have no more entries,
590 * or the inode has changed since we last read in the
591 * cached entries.
592 */
593 if ((!info->curr_node) ||
594 !inode_eq_iversion(inode, info->cookie)) {
595 info->curr_node = NULL;
596 free_rb_tree_fname(&info->root);
597 info->cookie = inode_query_iversion(inode);
598 ret = ext4_htree_fill_tree(file, info->curr_hash,
599 info->curr_minor_hash,
600 &info->next_hash);
601 if (ret < 0)
602 goto finished;
603 if (ret == 0) {
604 ctx->pos = ext4_get_htree_eof(file);
605 break;
606 }
607 info->curr_node = rb_first(&info->root);
608 }
609
610 fname = rb_entry(info->curr_node, struct fname, rb_hash);
611 info->curr_hash = fname->hash;
612 info->curr_minor_hash = fname->minor_hash;
613 if (call_filldir(file, ctx, fname))
614 break;
615 next_node:
616 info->curr_node = rb_next(info->curr_node);
617 if (info->curr_node) {
618 fname = rb_entry(info->curr_node, struct fname,
619 rb_hash);
620 info->curr_hash = fname->hash;
621 info->curr_minor_hash = fname->minor_hash;
622 } else {
623 if (info->next_hash == ~0) {
624 ctx->pos = ext4_get_htree_eof(file);
625 break;
626 }
627 info->curr_hash = info->next_hash;
628 info->curr_minor_hash = 0;
629 }
630 }
631 finished:
632 info->last_pos = ctx->pos;
633 return ret < 0 ? ret : 0;
634 }
635
ext4_release_dir(struct inode * inode,struct file * filp)636 static int ext4_release_dir(struct inode *inode, struct file *filp)
637 {
638 if (filp->private_data)
639 ext4_htree_free_dir_info(filp->private_data);
640
641 return 0;
642 }
643
ext4_check_all_de(struct inode * dir,struct buffer_head * bh,void * buf,int buf_size)644 int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
645 int buf_size)
646 {
647 struct ext4_dir_entry_2 *de;
648 int rlen;
649 unsigned int offset = 0;
650 char *top;
651
652 de = buf;
653 top = buf + buf_size;
654 while ((char *) de < top) {
655 if (ext4_check_dir_entry(dir, NULL, de, bh,
656 buf, buf_size, offset))
657 return -EFSCORRUPTED;
658 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
659 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
660 offset += rlen;
661 }
662 if ((char *) de > top)
663 return -EFSCORRUPTED;
664
665 return 0;
666 }
667
ext4_dir_open(struct inode * inode,struct file * file)668 static int ext4_dir_open(struct inode *inode, struct file *file)
669 {
670 struct dir_private_info *info;
671
672 info = kzalloc(sizeof(*info), GFP_KERNEL);
673 if (!info)
674 return -ENOMEM;
675 file->private_data = info;
676 return 0;
677 }
678
679 const struct file_operations ext4_dir_operations = {
680 .open = ext4_dir_open,
681 .llseek = ext4_dir_llseek,
682 .read = generic_read_dir,
683 .iterate_shared = ext4_readdir,
684 .unlocked_ioctl = ext4_ioctl,
685 #ifdef CONFIG_COMPAT
686 .compat_ioctl = ext4_compat_ioctl,
687 #endif
688 .fsync = ext4_sync_file,
689 .release = ext4_release_dir,
690 };
691