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/filelock.h>
28 #include <linux/slab.h>
29 #include <linux/iversion.h>
30 #include <linux/unicode.h>
31 #include "ext4.h"
32 #include "xattr.h"
33
34 static int ext4_dx_readdir(struct file *, struct dir_context *);
35
36 /**
37 * is_dx_dir() - check if a directory is using htree indexing
38 * @inode: directory inode
39 *
40 * Check if the given dir-inode refers to an htree-indexed directory
41 * (or a directory which could potentially get converted to use htree
42 * indexing).
43 *
44 * Return 1 if it is a dx dir, 0 if not
45 */
is_dx_dir(struct inode * inode)46 static int is_dx_dir(struct inode *inode)
47 {
48 struct super_block *sb = inode->i_sb;
49
50 if (ext4_has_feature_dir_index(inode->i_sb) &&
51 ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
52 ((inode->i_size >> sb->s_blocksize_bits) == 1) ||
53 ext4_has_inline_data(inode)))
54 return 1;
55
56 return 0;
57 }
58
is_fake_dir_entry(struct ext4_dir_entry_2 * de)59 static bool is_fake_dir_entry(struct ext4_dir_entry_2 *de)
60 {
61 /* Check if . or .. , or skip if namelen is 0 */
62 if ((de->name_len > 0) && (de->name_len <= 2) && (de->name[0] == '.') &&
63 (de->name[1] == '.' || de->name[1] == '\0'))
64 return true;
65 /* Check if this is a csum entry */
66 if (de->file_type == EXT4_FT_DIR_CSUM)
67 return true;
68 return false;
69 }
70
71 /*
72 * Return 0 if the directory entry is OK, and 1 if there is a problem
73 *
74 * Note: this is the opposite of what ext2 and ext3 historically returned...
75 *
76 * bh passed here can be an inode block or a dir data block, depending
77 * on the inode inline data flag.
78 */
__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)79 int __ext4_check_dir_entry(const char *function, unsigned int line,
80 struct inode *dir, struct file *filp,
81 struct ext4_dir_entry_2 *de,
82 struct buffer_head *bh, char *buf, int size,
83 unsigned int offset)
84 {
85 const char *error_msg = NULL;
86 const int rlen = ext4_rec_len_from_disk(de->rec_len,
87 dir->i_sb->s_blocksize);
88 const int next_offset = ((char *) de - buf) + rlen;
89 bool fake = is_fake_dir_entry(de);
90 bool has_csum = ext4_has_feature_metadata_csum(dir->i_sb);
91
92 if (unlikely(rlen < ext4_dir_rec_len(1, fake ? NULL : dir)))
93 error_msg = "rec_len is smaller than minimal";
94 else if (unlikely(rlen % 4 != 0))
95 error_msg = "rec_len % 4 != 0";
96 else if (unlikely(rlen < ext4_dir_rec_len(de->name_len,
97 fake ? NULL : dir)))
98 error_msg = "rec_len is too small for name_len";
99 else if (unlikely(next_offset > size))
100 error_msg = "directory entry overrun";
101 else if (unlikely(next_offset > size - ext4_dir_rec_len(1,
102 has_csum ? NULL : dir) &&
103 next_offset != size))
104 error_msg = "directory entry too close to block end";
105 else if (unlikely(le32_to_cpu(de->inode) >
106 le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
107 error_msg = "inode out of bounds";
108 else if (unlikely(next_offset == size && de->name_len == 1 &&
109 de->name[0] == '.'))
110 error_msg = "'.' directory cannot be the last in data block";
111 else
112 return 0;
113
114 if (filp)
115 ext4_error_file(filp, function, line, bh->b_blocknr,
116 "bad entry in directory: %s - offset=%u, "
117 "inode=%u, rec_len=%d, size=%d fake=%d",
118 error_msg, offset, le32_to_cpu(de->inode),
119 rlen, size, fake);
120 else
121 ext4_error_inode(dir, function, line, bh->b_blocknr,
122 "bad entry in directory: %s - offset=%u, "
123 "inode=%u, rec_len=%d, size=%d fake=%d",
124 error_msg, offset, le32_to_cpu(de->inode),
125 rlen, size, fake);
126
127 return 1;
128 }
129
ext4_readdir(struct file * file,struct dir_context * ctx)130 static int ext4_readdir(struct file *file, struct dir_context *ctx)
131 {
132 unsigned int offset;
133 int i;
134 struct ext4_dir_entry_2 *de;
135 int err;
136 struct inode *inode = file_inode(file);
137 struct super_block *sb = inode->i_sb;
138 struct buffer_head *bh = NULL;
139 struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
140 struct dir_private_info *info = file->private_data;
141
142 err = fscrypt_prepare_readdir(inode);
143 if (err)
144 return err;
145
146 if (is_dx_dir(inode)) {
147 err = ext4_dx_readdir(file, ctx);
148 if (err != ERR_BAD_DX_DIR)
149 return err;
150
151 /* Can we just clear INDEX flag to ignore htree information? */
152 if (!ext4_has_feature_metadata_csum(sb)) {
153 /*
154 * We don't set the inode dirty flag since it's not
155 * critical that it gets flushed back to the disk.
156 */
157 ext4_clear_inode_flag(inode, EXT4_INODE_INDEX);
158 }
159 }
160
161 if (ext4_has_inline_data(inode)) {
162 int has_inline_data = 1;
163 err = ext4_read_inline_dir(file, ctx,
164 &has_inline_data);
165 if (has_inline_data)
166 return err;
167 }
168
169 if (IS_ENCRYPTED(inode)) {
170 err = fscrypt_fname_alloc_buffer(EXT4_NAME_LEN, &fstr);
171 if (err < 0)
172 return err;
173 }
174
175 while (ctx->pos < inode->i_size) {
176 struct ext4_map_blocks map;
177
178 if (fatal_signal_pending(current)) {
179 err = -ERESTARTSYS;
180 goto errout;
181 }
182 cond_resched();
183 offset = ctx->pos & (sb->s_blocksize - 1);
184 map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
185 map.m_len = 1;
186 err = ext4_map_blocks(NULL, inode, &map, 0);
187 if (err == 0) {
188 /* m_len should never be zero but let's avoid
189 * an infinite loop if it somehow is */
190 if (map.m_len == 0)
191 map.m_len = 1;
192 ctx->pos += map.m_len * sb->s_blocksize;
193 continue;
194 }
195 if (err > 0) {
196 pgoff_t index = map.m_pblk << inode->i_blkbits >>
197 PAGE_SHIFT;
198 if (!ra_has_index(&file->f_ra, index))
199 page_cache_sync_readahead(
200 sb->s_bdev->bd_mapping,
201 &file->f_ra, file, index,
202 1 << EXT4_SB(sb)->s_min_folio_order);
203 file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
204 bh = ext4_bread(NULL, inode, map.m_lblk, 0);
205 if (IS_ERR(bh)) {
206 err = PTR_ERR(bh);
207 bh = NULL;
208 goto errout;
209 }
210 }
211
212 if (!bh) {
213 /* corrupt size? Maybe no more blocks to read */
214 if (ctx->pos > inode->i_blocks << 9)
215 break;
216 ctx->pos += sb->s_blocksize - offset;
217 continue;
218 }
219
220 /* Check the checksum */
221 if (!buffer_verified(bh) &&
222 !ext4_dirblock_csum_verify(inode, bh)) {
223 EXT4_ERROR_FILE(file, 0, "directory fails checksum "
224 "at offset %llu",
225 (unsigned long long)ctx->pos);
226 ctx->pos += sb->s_blocksize - offset;
227 brelse(bh);
228 bh = NULL;
229 continue;
230 }
231 set_buffer_verified(bh);
232
233 /* If the dir block has changed since the last call to
234 * readdir(2), then we might be pointing to an invalid
235 * dirent right now. Scan from the start of the block
236 * to make sure. */
237 if (!inode_eq_iversion(inode, info->cookie)) {
238 for (i = 0; i < sb->s_blocksize && i < offset; ) {
239 de = (struct ext4_dir_entry_2 *)
240 (bh->b_data + i);
241 /* It's too expensive to do a full
242 * dirent test each time round this
243 * loop, but we do have to test at
244 * least that it is non-zero. A
245 * failure will be detected in the
246 * dirent test below. */
247 if (ext4_rec_len_from_disk(de->rec_len,
248 sb->s_blocksize) < ext4_dir_rec_len(1,
249 inode))
250 break;
251 i += ext4_rec_len_from_disk(de->rec_len,
252 sb->s_blocksize);
253 }
254 offset = i;
255 ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
256 | offset;
257 info->cookie = inode_query_iversion(inode);
258 }
259
260 while (ctx->pos < inode->i_size
261 && offset < sb->s_blocksize) {
262 de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
263 if (ext4_check_dir_entry(inode, file, de, bh,
264 bh->b_data, bh->b_size,
265 offset)) {
266 /*
267 * On error, skip to the next block
268 */
269 ctx->pos = (ctx->pos |
270 (sb->s_blocksize - 1)) + 1;
271 break;
272 }
273 offset += ext4_rec_len_from_disk(de->rec_len,
274 sb->s_blocksize);
275 if (le32_to_cpu(de->inode)) {
276 if (!IS_ENCRYPTED(inode)) {
277 if (!dir_emit(ctx, de->name,
278 de->name_len,
279 le32_to_cpu(de->inode),
280 get_dtype(sb, de->file_type)))
281 goto done;
282 } else {
283 int save_len = fstr.len;
284 struct fscrypt_str de_name =
285 FSTR_INIT(de->name,
286 de->name_len);
287 u32 hash;
288 u32 minor_hash;
289
290 if (IS_CASEFOLDED(inode)) {
291 hash = EXT4_DIRENT_HASH(de);
292 minor_hash = EXT4_DIRENT_MINOR_HASH(de);
293 } else {
294 hash = 0;
295 minor_hash = 0;
296 }
297
298 /* Directory is encrypted */
299 err = fscrypt_fname_disk_to_usr(inode,
300 hash, minor_hash, &de_name, &fstr);
301 de_name = fstr;
302 fstr.len = save_len;
303 if (err)
304 goto errout;
305 if (!dir_emit(ctx,
306 de_name.name, de_name.len,
307 le32_to_cpu(de->inode),
308 get_dtype(sb, de->file_type)))
309 goto done;
310 }
311 }
312 ctx->pos += ext4_rec_len_from_disk(de->rec_len,
313 sb->s_blocksize);
314 }
315 if ((ctx->pos < inode->i_size) && !dir_relax_shared(inode))
316 goto done;
317 brelse(bh);
318 bh = NULL;
319 }
320 done:
321 err = 0;
322 errout:
323 fscrypt_fname_free_buffer(&fstr);
324 brelse(bh);
325 return err;
326 }
327
is_32bit_api(void)328 static inline int is_32bit_api(void)
329 {
330 #ifdef CONFIG_COMPAT
331 return in_compat_syscall();
332 #else
333 return (BITS_PER_LONG == 32);
334 #endif
335 }
336
337 /*
338 * These functions convert from the major/minor hash to an f_pos
339 * value for dx directories
340 *
341 * Upper layer (for example NFS) should specify FMODE_32BITHASH or
342 * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
343 * directly on both 32-bit and 64-bit nodes, under such case, neither
344 * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
345 */
hash2pos(struct file * filp,__u32 major,__u32 minor)346 static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
347 {
348 if ((filp->f_mode & FMODE_32BITHASH) ||
349 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
350 return major >> 1;
351 else
352 return ((__u64)(major >> 1) << 32) | (__u64)minor;
353 }
354
pos2maj_hash(struct file * filp,loff_t pos)355 static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
356 {
357 if ((filp->f_mode & FMODE_32BITHASH) ||
358 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
359 return (pos << 1) & 0xffffffff;
360 else
361 return ((pos >> 32) << 1) & 0xffffffff;
362 }
363
pos2min_hash(struct file * filp,loff_t pos)364 static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
365 {
366 if ((filp->f_mode & FMODE_32BITHASH) ||
367 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
368 return 0;
369 else
370 return pos & 0xffffffff;
371 }
372
373 /*
374 * Return 32- or 64-bit end-of-file for dx directories
375 */
ext4_get_htree_eof(struct file * filp)376 static inline loff_t ext4_get_htree_eof(struct file *filp)
377 {
378 if ((filp->f_mode & FMODE_32BITHASH) ||
379 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
380 return EXT4_HTREE_EOF_32BIT;
381 else
382 return EXT4_HTREE_EOF_64BIT;
383 }
384
385
386 /*
387 * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
388 * directories, where the "offset" is in terms of the filename hash
389 * value instead of the byte offset.
390 *
391 * Because we may return a 64-bit hash that is well beyond offset limits,
392 * we need to pass the max hash as the maximum allowable offset in
393 * the htree directory case.
394 *
395 * For non-htree, ext4_llseek already chooses the proper max offset.
396 */
ext4_dir_llseek(struct file * file,loff_t offset,int whence)397 static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
398 {
399 struct inode *inode = file->f_mapping->host;
400 struct dir_private_info *info = file->private_data;
401 int dx_dir = is_dx_dir(inode);
402 loff_t ret, htree_max = ext4_get_htree_eof(file);
403
404 if (likely(dx_dir))
405 ret = generic_file_llseek_size(file, offset, whence,
406 htree_max, htree_max);
407 else
408 ret = ext4_llseek(file, offset, whence);
409 info->cookie = inode_peek_iversion(inode) - 1;
410 return ret;
411 }
412
413 /*
414 * This structure holds the nodes of the red-black tree used to store
415 * the directory entry in hash order.
416 */
417 struct fname {
418 __u32 hash;
419 __u32 minor_hash;
420 struct rb_node rb_hash;
421 struct fname *next;
422 __u32 inode;
423 __u8 name_len;
424 __u8 file_type;
425 char name[] __counted_by(name_len);
426 };
427
428 /*
429 * This function implements a non-recursive way of freeing all of the
430 * nodes in the red-black tree.
431 */
free_rb_tree_fname(struct rb_root * root)432 static void free_rb_tree_fname(struct rb_root *root)
433 {
434 struct fname *fname, *next;
435
436 rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
437 while (fname) {
438 struct fname *old = fname;
439 fname = fname->next;
440 kfree(old);
441 }
442
443 *root = RB_ROOT;
444 }
445
ext4_htree_init_dir_info(struct file * filp,loff_t pos)446 static void ext4_htree_init_dir_info(struct file *filp, loff_t pos)
447 {
448 struct dir_private_info *p = filp->private_data;
449
450 if (is_dx_dir(file_inode(filp)) && !p->initialized) {
451 p->curr_hash = pos2maj_hash(filp, pos);
452 p->curr_minor_hash = pos2min_hash(filp, pos);
453 p->initialized = true;
454 }
455 }
456
ext4_htree_free_dir_info(struct dir_private_info * p)457 void ext4_htree_free_dir_info(struct dir_private_info *p)
458 {
459 free_rb_tree_fname(&p->root);
460 kfree(p);
461 }
462
463 /*
464 * Given a directory entry, enter it into the fname rb tree.
465 *
466 * When filename encryption is enabled, the dirent will hold the
467 * encrypted filename, while the htree will hold decrypted filename.
468 * The decrypted filename is passed in via ent_name. parameter.
469 */
ext4_htree_store_dirent(struct file * dir_file,__u32 hash,__u32 minor_hash,struct ext4_dir_entry_2 * dirent,struct fscrypt_str * ent_name)470 int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
471 __u32 minor_hash,
472 struct ext4_dir_entry_2 *dirent,
473 struct fscrypt_str *ent_name)
474 {
475 struct rb_node **p, *parent = NULL;
476 struct fname *fname, *new_fn;
477 struct dir_private_info *info;
478
479 info = dir_file->private_data;
480 p = &info->root.rb_node;
481
482 /* Create and allocate the fname structure */
483 new_fn = kzalloc_flex(*new_fn, name, ent_name->len + 1);
484 if (!new_fn)
485 return -ENOMEM;
486 new_fn->hash = hash;
487 new_fn->minor_hash = minor_hash;
488 new_fn->inode = le32_to_cpu(dirent->inode);
489 new_fn->name_len = ent_name->len;
490 new_fn->file_type = dirent->file_type;
491 memcpy(new_fn->name, ent_name->name, ent_name->len);
492
493 while (*p) {
494 parent = *p;
495 fname = rb_entry(parent, struct fname, rb_hash);
496
497 /*
498 * If the hash and minor hash match up, then we put
499 * them on a linked list. This rarely happens...
500 */
501 if ((new_fn->hash == fname->hash) &&
502 (new_fn->minor_hash == fname->minor_hash)) {
503 new_fn->next = fname->next;
504 fname->next = new_fn;
505 return 0;
506 }
507
508 if (new_fn->hash < fname->hash)
509 p = &(*p)->rb_left;
510 else if (new_fn->hash > fname->hash)
511 p = &(*p)->rb_right;
512 else if (new_fn->minor_hash < fname->minor_hash)
513 p = &(*p)->rb_left;
514 else /* if (new_fn->minor_hash > fname->minor_hash) */
515 p = &(*p)->rb_right;
516 }
517
518 rb_link_node(&new_fn->rb_hash, parent, p);
519 rb_insert_color(&new_fn->rb_hash, &info->root);
520 return 0;
521 }
522
523
524
525 /*
526 * This is a helper function for ext4_dx_readdir. It calls filldir
527 * for all entries on the fname linked list. (Normally there is only
528 * one entry on the linked list, unless there are 62 bit hash collisions.)
529 */
call_filldir(struct file * file,struct dir_context * ctx,struct fname * fname)530 static int call_filldir(struct file *file, struct dir_context *ctx,
531 struct fname *fname)
532 {
533 struct dir_private_info *info = file->private_data;
534 struct inode *inode = file_inode(file);
535 struct super_block *sb = inode->i_sb;
536
537 if (!fname) {
538 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
539 "called with null fname?!?", __func__, __LINE__,
540 inode->i_ino, current->comm);
541 return 0;
542 }
543 ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
544 while (fname) {
545 if (!dir_emit(ctx, fname->name,
546 fname->name_len,
547 fname->inode,
548 get_dtype(sb, fname->file_type))) {
549 info->extra_fname = fname;
550 return 1;
551 }
552 fname = fname->next;
553 }
554 return 0;
555 }
556
ext4_dx_readdir(struct file * file,struct dir_context * ctx)557 static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
558 {
559 struct dir_private_info *info = file->private_data;
560 struct inode *inode = file_inode(file);
561 struct fname *fname;
562 int ret = 0;
563
564 ext4_htree_init_dir_info(file, ctx->pos);
565
566 if (ctx->pos == ext4_get_htree_eof(file))
567 return 0; /* EOF */
568
569 /* Some one has messed with f_pos; reset the world */
570 if (info->last_pos != ctx->pos) {
571 free_rb_tree_fname(&info->root);
572 info->curr_node = NULL;
573 info->extra_fname = NULL;
574 info->curr_hash = pos2maj_hash(file, ctx->pos);
575 info->curr_minor_hash = pos2min_hash(file, ctx->pos);
576 }
577
578 /*
579 * If there are any leftover names on the hash collision
580 * chain, return them first.
581 */
582 if (info->extra_fname) {
583 if (call_filldir(file, ctx, info->extra_fname))
584 goto finished;
585 info->extra_fname = NULL;
586 goto next_node;
587 } else if (!info->curr_node)
588 info->curr_node = rb_first(&info->root);
589
590 while (1) {
591 /*
592 * Fill the rbtree if we have no more entries,
593 * or the inode has changed since we last read in the
594 * cached entries.
595 */
596 if ((!info->curr_node) ||
597 !inode_eq_iversion(inode, info->cookie)) {
598 info->curr_node = NULL;
599 free_rb_tree_fname(&info->root);
600 info->cookie = inode_query_iversion(inode);
601 ret = ext4_htree_fill_tree(file, info->curr_hash,
602 info->curr_minor_hash,
603 &info->next_hash);
604 if (ret < 0)
605 goto finished;
606 if (ret == 0) {
607 ctx->pos = ext4_get_htree_eof(file);
608 break;
609 }
610 info->curr_node = rb_first(&info->root);
611 }
612
613 fname = rb_entry(info->curr_node, struct fname, rb_hash);
614 info->curr_hash = fname->hash;
615 info->curr_minor_hash = fname->minor_hash;
616 if (call_filldir(file, ctx, fname))
617 break;
618 next_node:
619 info->curr_node = rb_next(info->curr_node);
620 if (info->curr_node) {
621 fname = rb_entry(info->curr_node, struct fname,
622 rb_hash);
623 info->curr_hash = fname->hash;
624 info->curr_minor_hash = fname->minor_hash;
625 } else {
626 if (info->next_hash == ~0) {
627 ctx->pos = ext4_get_htree_eof(file);
628 break;
629 }
630 info->curr_hash = info->next_hash;
631 info->curr_minor_hash = 0;
632 }
633 }
634 finished:
635 info->last_pos = ctx->pos;
636 return ret < 0 ? ret : 0;
637 }
638
ext4_release_dir(struct inode * inode,struct file * filp)639 static int ext4_release_dir(struct inode *inode, struct file *filp)
640 {
641 if (filp->private_data)
642 ext4_htree_free_dir_info(filp->private_data);
643
644 return 0;
645 }
646
ext4_check_all_de(struct inode * dir,struct buffer_head * bh,void * buf,int buf_size)647 int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
648 int buf_size)
649 {
650 struct ext4_dir_entry_2 *de;
651 int rlen;
652 unsigned int offset = 0;
653 char *top;
654
655 de = buf;
656 top = buf + buf_size;
657 while ((char *) de < top) {
658 if (ext4_check_dir_entry(dir, NULL, de, bh,
659 buf, buf_size, offset))
660 return -EFSCORRUPTED;
661 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
662 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
663 offset += rlen;
664 }
665 if ((char *) de > top)
666 return -EFSCORRUPTED;
667
668 return 0;
669 }
670
ext4_dir_open(struct inode * inode,struct file * file)671 static int ext4_dir_open(struct inode *inode, struct file *file)
672 {
673 struct dir_private_info *info;
674
675 info = kzalloc_obj(*info);
676 if (!info)
677 return -ENOMEM;
678 file->private_data = info;
679 return 0;
680 }
681
682 const struct file_operations ext4_dir_operations = {
683 .open = ext4_dir_open,
684 .llseek = ext4_dir_llseek,
685 .read = generic_read_dir,
686 .iterate_shared = ext4_readdir,
687 .unlocked_ioctl = ext4_ioctl,
688 #ifdef CONFIG_COMPAT
689 .compat_ioctl = ext4_compat_ioctl,
690 #endif
691 .fsync = ext4_sync_file,
692 .release = ext4_release_dir,
693 .setlease = generic_setlease,
694 };
695