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
58 /*
59 * Return 0 if the directory entry is OK, and 1 if there is a problem
60 *
61 * Note: this is the opposite of what ext2 and ext3 historically returned...
62 *
63 * bh passed here can be an inode block or a dir data block, depending
64 * on the inode inline data flag.
65 */
__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)66 int __ext4_check_dir_entry(const char *function, unsigned int line,
67 struct inode *dir, struct file *filp,
68 struct ext4_dir_entry_2 *de,
69 struct buffer_head *bh, char *buf, int size,
70 unsigned int offset)
71 {
72 const char *error_msg = NULL;
73 const int rlen = ext4_rec_len_from_disk(de->rec_len,
74 dir->i_sb->s_blocksize);
75
76 if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
77 error_msg = "rec_len is smaller than minimal";
78 else if (unlikely(rlen % 4 != 0))
79 error_msg = "rec_len % 4 != 0";
80 else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
81 error_msg = "rec_len is too small for name_len";
82 else if (unlikely(((char *) de - buf) + rlen > size))
83 error_msg = "directory entry overrun";
84 else if (unlikely(((char *) de - buf) + rlen >
85 size - EXT4_DIR_REC_LEN(1) &&
86 ((char *) de - buf) + rlen != size)) {
87 error_msg = "directory entry too close to block end";
88 }
89 else if (unlikely(le32_to_cpu(de->inode) >
90 le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
91 error_msg = "inode out of bounds";
92 else
93 return 0;
94
95 if (filp)
96 ext4_error_file(filp, function, line, bh->b_blocknr,
97 "bad entry in directory: %s - offset=%u, "
98 "inode=%u, rec_len=%d, name_len=%d, size=%d",
99 error_msg, offset, le32_to_cpu(de->inode),
100 rlen, de->name_len, size);
101 else
102 ext4_error_inode(dir, function, line, bh->b_blocknr,
103 "bad entry in directory: %s - offset=%u, "
104 "inode=%u, rec_len=%d, name_len=%d, size=%d",
105 error_msg, offset, le32_to_cpu(de->inode),
106 rlen, de->name_len, size);
107
108 return 1;
109 }
110
ext4_readdir(struct file * file,struct dir_context * ctx)111 static int ext4_readdir(struct file *file, struct dir_context *ctx)
112 {
113 unsigned int offset;
114 int i;
115 struct ext4_dir_entry_2 *de;
116 int err;
117 struct inode *inode = file_inode(file);
118 struct super_block *sb = inode->i_sb;
119 struct buffer_head *bh = NULL;
120 struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
121
122 if (IS_ENCRYPTED(inode)) {
123 err = fscrypt_get_encryption_info(inode);
124 if (err && err != -ENOKEY)
125 return err;
126 }
127
128 if (is_dx_dir(inode)) {
129 err = ext4_dx_readdir(file, ctx);
130 if (err != ERR_BAD_DX_DIR) {
131 return err;
132 }
133 /*
134 * We don't set the inode dirty flag since it's not
135 * critical that it get flushed back to the disk.
136 */
137 ext4_clear_inode_flag(file_inode(file),
138 EXT4_INODE_INDEX);
139 }
140
141 if (ext4_has_inline_data(inode)) {
142 int has_inline_data = 1;
143 err = ext4_read_inline_dir(file, ctx,
144 &has_inline_data);
145 if (has_inline_data)
146 return err;
147 }
148
149 if (IS_ENCRYPTED(inode)) {
150 err = fscrypt_fname_alloc_buffer(inode, EXT4_NAME_LEN, &fstr);
151 if (err < 0)
152 return err;
153 }
154
155 while (ctx->pos < inode->i_size) {
156 struct ext4_map_blocks map;
157
158 if (fatal_signal_pending(current)) {
159 err = -ERESTARTSYS;
160 goto errout;
161 }
162 cond_resched();
163 offset = ctx->pos & (sb->s_blocksize - 1);
164 map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
165 map.m_len = 1;
166 err = ext4_map_blocks(NULL, inode, &map, 0);
167 if (err == 0) {
168 /* m_len should never be zero but let's avoid
169 * an infinite loop if it somehow is */
170 if (map.m_len == 0)
171 map.m_len = 1;
172 ctx->pos += map.m_len * sb->s_blocksize;
173 continue;
174 }
175 if (err > 0) {
176 pgoff_t index = map.m_pblk >>
177 (PAGE_SHIFT - inode->i_blkbits);
178 if (!ra_has_index(&file->f_ra, index))
179 page_cache_sync_readahead(
180 sb->s_bdev->bd_inode->i_mapping,
181 &file->f_ra, file,
182 index, 1);
183 file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
184 bh = ext4_bread(NULL, inode, map.m_lblk, 0);
185 if (IS_ERR(bh)) {
186 err = PTR_ERR(bh);
187 bh = NULL;
188 goto errout;
189 }
190 }
191
192 if (!bh) {
193 /* corrupt size? Maybe no more blocks to read */
194 if (ctx->pos > inode->i_blocks << 9)
195 break;
196 ctx->pos += sb->s_blocksize - offset;
197 continue;
198 }
199
200 /* Check the checksum */
201 if (!buffer_verified(bh) &&
202 !ext4_dirblock_csum_verify(inode, bh)) {
203 EXT4_ERROR_FILE(file, 0, "directory fails checksum "
204 "at offset %llu",
205 (unsigned long long)ctx->pos);
206 ctx->pos += sb->s_blocksize - offset;
207 brelse(bh);
208 bh = NULL;
209 continue;
210 }
211 set_buffer_verified(bh);
212
213 /* If the dir block has changed since the last call to
214 * readdir(2), then we might be pointing to an invalid
215 * dirent right now. Scan from the start of the block
216 * to make sure. */
217 if (!inode_eq_iversion(inode, file->f_version)) {
218 for (i = 0; i < sb->s_blocksize && i < offset; ) {
219 de = (struct ext4_dir_entry_2 *)
220 (bh->b_data + i);
221 /* It's too expensive to do a full
222 * dirent test each time round this
223 * loop, but we do have to test at
224 * least that it is non-zero. A
225 * failure will be detected in the
226 * dirent test below. */
227 if (ext4_rec_len_from_disk(de->rec_len,
228 sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
229 break;
230 i += ext4_rec_len_from_disk(de->rec_len,
231 sb->s_blocksize);
232 }
233 offset = i;
234 ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
235 | offset;
236 file->f_version = inode_query_iversion(inode);
237 }
238
239 while (ctx->pos < inode->i_size
240 && offset < sb->s_blocksize) {
241 de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
242 if (ext4_check_dir_entry(inode, file, de, bh,
243 bh->b_data, bh->b_size,
244 offset)) {
245 /*
246 * On error, skip to the next block
247 */
248 ctx->pos = (ctx->pos |
249 (sb->s_blocksize - 1)) + 1;
250 break;
251 }
252 offset += ext4_rec_len_from_disk(de->rec_len,
253 sb->s_blocksize);
254 if (le32_to_cpu(de->inode)) {
255 if (!IS_ENCRYPTED(inode)) {
256 if (!dir_emit(ctx, de->name,
257 de->name_len,
258 le32_to_cpu(de->inode),
259 get_dtype(sb, de->file_type)))
260 goto done;
261 } else {
262 int save_len = fstr.len;
263 struct fscrypt_str de_name =
264 FSTR_INIT(de->name,
265 de->name_len);
266
267 /* Directory is encrypted */
268 err = fscrypt_fname_disk_to_usr(inode,
269 0, 0, &de_name, &fstr);
270 de_name = fstr;
271 fstr.len = save_len;
272 if (err)
273 goto errout;
274 if (!dir_emit(ctx,
275 de_name.name, de_name.len,
276 le32_to_cpu(de->inode),
277 get_dtype(sb, de->file_type)))
278 goto done;
279 }
280 }
281 ctx->pos += ext4_rec_len_from_disk(de->rec_len,
282 sb->s_blocksize);
283 }
284 if ((ctx->pos < inode->i_size) && !dir_relax_shared(inode))
285 goto done;
286 brelse(bh);
287 bh = NULL;
288 offset = 0;
289 }
290 done:
291 err = 0;
292 errout:
293 fscrypt_fname_free_buffer(&fstr);
294 brelse(bh);
295 return err;
296 }
297
is_32bit_api(void)298 static inline int is_32bit_api(void)
299 {
300 #ifdef CONFIG_COMPAT
301 return in_compat_syscall();
302 #else
303 return (BITS_PER_LONG == 32);
304 #endif
305 }
306
307 /*
308 * These functions convert from the major/minor hash to an f_pos
309 * value for dx directories
310 *
311 * Upper layer (for example NFS) should specify FMODE_32BITHASH or
312 * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
313 * directly on both 32-bit and 64-bit nodes, under such case, neither
314 * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
315 */
hash2pos(struct file * filp,__u32 major,__u32 minor)316 static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
317 {
318 if ((filp->f_mode & FMODE_32BITHASH) ||
319 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
320 return major >> 1;
321 else
322 return ((__u64)(major >> 1) << 32) | (__u64)minor;
323 }
324
pos2maj_hash(struct file * filp,loff_t pos)325 static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
326 {
327 if ((filp->f_mode & FMODE_32BITHASH) ||
328 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
329 return (pos << 1) & 0xffffffff;
330 else
331 return ((pos >> 32) << 1) & 0xffffffff;
332 }
333
pos2min_hash(struct file * filp,loff_t pos)334 static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
335 {
336 if ((filp->f_mode & FMODE_32BITHASH) ||
337 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
338 return 0;
339 else
340 return pos & 0xffffffff;
341 }
342
343 /*
344 * Return 32- or 64-bit end-of-file for dx directories
345 */
ext4_get_htree_eof(struct file * filp)346 static inline loff_t ext4_get_htree_eof(struct file *filp)
347 {
348 if ((filp->f_mode & FMODE_32BITHASH) ||
349 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
350 return EXT4_HTREE_EOF_32BIT;
351 else
352 return EXT4_HTREE_EOF_64BIT;
353 }
354
355
356 /*
357 * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
358 * directories, where the "offset" is in terms of the filename hash
359 * value instead of the byte offset.
360 *
361 * Because we may return a 64-bit hash that is well beyond offset limits,
362 * we need to pass the max hash as the maximum allowable offset in
363 * the htree directory case.
364 *
365 * For non-htree, ext4_llseek already chooses the proper max offset.
366 */
ext4_dir_llseek(struct file * file,loff_t offset,int whence)367 static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
368 {
369 struct inode *inode = file->f_mapping->host;
370 int dx_dir = is_dx_dir(inode);
371 loff_t ret, htree_max = ext4_get_htree_eof(file);
372
373 if (likely(dx_dir))
374 ret = generic_file_llseek_size(file, offset, whence,
375 htree_max, htree_max);
376 else
377 ret = ext4_llseek(file, offset, whence);
378 file->f_version = inode_peek_iversion(inode) - 1;
379 return ret;
380 }
381
382 /*
383 * This structure holds the nodes of the red-black tree used to store
384 * the directory entry in hash order.
385 */
386 struct fname {
387 __u32 hash;
388 __u32 minor_hash;
389 struct rb_node rb_hash;
390 struct fname *next;
391 __u32 inode;
392 __u8 name_len;
393 __u8 file_type;
394 char name[0];
395 };
396
397 /*
398 * This functoin implements a non-recursive way of freeing all of the
399 * nodes in the red-black tree.
400 */
free_rb_tree_fname(struct rb_root * root)401 static void free_rb_tree_fname(struct rb_root *root)
402 {
403 struct fname *fname, *next;
404
405 rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
406 while (fname) {
407 struct fname *old = fname;
408 fname = fname->next;
409 kfree(old);
410 }
411
412 *root = RB_ROOT;
413 }
414
415
ext4_htree_create_dir_info(struct file * filp,loff_t pos)416 static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
417 loff_t pos)
418 {
419 struct dir_private_info *p;
420
421 p = kzalloc(sizeof(*p), GFP_KERNEL);
422 if (!p)
423 return NULL;
424 p->curr_hash = pos2maj_hash(filp, pos);
425 p->curr_minor_hash = pos2min_hash(filp, pos);
426 return p;
427 }
428
ext4_htree_free_dir_info(struct dir_private_info * p)429 void ext4_htree_free_dir_info(struct dir_private_info *p)
430 {
431 free_rb_tree_fname(&p->root);
432 kfree(p);
433 }
434
435 /*
436 * Given a directory entry, enter it into the fname rb tree.
437 *
438 * When filename encryption is enabled, the dirent will hold the
439 * encrypted filename, while the htree will hold decrypted filename.
440 * The decrypted filename is passed in via ent_name. parameter.
441 */
ext4_htree_store_dirent(struct file * dir_file,__u32 hash,__u32 minor_hash,struct ext4_dir_entry_2 * dirent,struct fscrypt_str * ent_name)442 int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
443 __u32 minor_hash,
444 struct ext4_dir_entry_2 *dirent,
445 struct fscrypt_str *ent_name)
446 {
447 struct rb_node **p, *parent = NULL;
448 struct fname *fname, *new_fn;
449 struct dir_private_info *info;
450 int len;
451
452 info = dir_file->private_data;
453 p = &info->root.rb_node;
454
455 /* Create and allocate the fname structure */
456 len = sizeof(struct fname) + ent_name->len + 1;
457 new_fn = kzalloc(len, GFP_KERNEL);
458 if (!new_fn)
459 return -ENOMEM;
460 new_fn->hash = hash;
461 new_fn->minor_hash = minor_hash;
462 new_fn->inode = le32_to_cpu(dirent->inode);
463 new_fn->name_len = ent_name->len;
464 new_fn->file_type = dirent->file_type;
465 memcpy(new_fn->name, ent_name->name, ent_name->len);
466 new_fn->name[ent_name->len] = 0;
467
468 while (*p) {
469 parent = *p;
470 fname = rb_entry(parent, struct fname, rb_hash);
471
472 /*
473 * If the hash and minor hash match up, then we put
474 * them on a linked list. This rarely happens...
475 */
476 if ((new_fn->hash == fname->hash) &&
477 (new_fn->minor_hash == fname->minor_hash)) {
478 new_fn->next = fname->next;
479 fname->next = new_fn;
480 return 0;
481 }
482
483 if (new_fn->hash < fname->hash)
484 p = &(*p)->rb_left;
485 else if (new_fn->hash > fname->hash)
486 p = &(*p)->rb_right;
487 else if (new_fn->minor_hash < fname->minor_hash)
488 p = &(*p)->rb_left;
489 else /* if (new_fn->minor_hash > fname->minor_hash) */
490 p = &(*p)->rb_right;
491 }
492
493 rb_link_node(&new_fn->rb_hash, parent, p);
494 rb_insert_color(&new_fn->rb_hash, &info->root);
495 return 0;
496 }
497
498
499
500 /*
501 * This is a helper function for ext4_dx_readdir. It calls filldir
502 * for all entres on the fname linked list. (Normally there is only
503 * one entry on the linked list, unless there are 62 bit hash collisions.)
504 */
call_filldir(struct file * file,struct dir_context * ctx,struct fname * fname)505 static int call_filldir(struct file *file, struct dir_context *ctx,
506 struct fname *fname)
507 {
508 struct dir_private_info *info = file->private_data;
509 struct inode *inode = file_inode(file);
510 struct super_block *sb = inode->i_sb;
511
512 if (!fname) {
513 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
514 "called with null fname?!?", __func__, __LINE__,
515 inode->i_ino, current->comm);
516 return 0;
517 }
518 ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
519 while (fname) {
520 if (!dir_emit(ctx, fname->name,
521 fname->name_len,
522 fname->inode,
523 get_dtype(sb, fname->file_type))) {
524 info->extra_fname = fname;
525 return 1;
526 }
527 fname = fname->next;
528 }
529 return 0;
530 }
531
ext4_dx_readdir(struct file * file,struct dir_context * ctx)532 static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
533 {
534 struct dir_private_info *info = file->private_data;
535 struct inode *inode = file_inode(file);
536 struct fname *fname;
537 int ret;
538
539 if (!info) {
540 info = ext4_htree_create_dir_info(file, ctx->pos);
541 if (!info)
542 return -ENOMEM;
543 file->private_data = info;
544 }
545
546 if (ctx->pos == ext4_get_htree_eof(file))
547 return 0; /* EOF */
548
549 /* Some one has messed with f_pos; reset the world */
550 if (info->last_pos != ctx->pos) {
551 free_rb_tree_fname(&info->root);
552 info->curr_node = NULL;
553 info->extra_fname = NULL;
554 info->curr_hash = pos2maj_hash(file, ctx->pos);
555 info->curr_minor_hash = pos2min_hash(file, ctx->pos);
556 }
557
558 /*
559 * If there are any leftover names on the hash collision
560 * chain, return them first.
561 */
562 if (info->extra_fname) {
563 if (call_filldir(file, ctx, info->extra_fname))
564 goto finished;
565 info->extra_fname = NULL;
566 goto next_node;
567 } else if (!info->curr_node)
568 info->curr_node = rb_first(&info->root);
569
570 while (1) {
571 /*
572 * Fill the rbtree if we have no more entries,
573 * or the inode has changed since we last read in the
574 * cached entries.
575 */
576 if ((!info->curr_node) ||
577 !inode_eq_iversion(inode, file->f_version)) {
578 info->curr_node = NULL;
579 free_rb_tree_fname(&info->root);
580 file->f_version = inode_query_iversion(inode);
581 ret = ext4_htree_fill_tree(file, info->curr_hash,
582 info->curr_minor_hash,
583 &info->next_hash);
584 if (ret < 0)
585 return ret;
586 if (ret == 0) {
587 ctx->pos = ext4_get_htree_eof(file);
588 break;
589 }
590 info->curr_node = rb_first(&info->root);
591 }
592
593 fname = rb_entry(info->curr_node, struct fname, rb_hash);
594 info->curr_hash = fname->hash;
595 info->curr_minor_hash = fname->minor_hash;
596 if (call_filldir(file, ctx, fname))
597 break;
598 next_node:
599 info->curr_node = rb_next(info->curr_node);
600 if (info->curr_node) {
601 fname = rb_entry(info->curr_node, struct fname,
602 rb_hash);
603 info->curr_hash = fname->hash;
604 info->curr_minor_hash = fname->minor_hash;
605 } else {
606 if (info->next_hash == ~0) {
607 ctx->pos = ext4_get_htree_eof(file);
608 break;
609 }
610 info->curr_hash = info->next_hash;
611 info->curr_minor_hash = 0;
612 }
613 }
614 finished:
615 info->last_pos = ctx->pos;
616 return 0;
617 }
618
ext4_dir_open(struct inode * inode,struct file * filp)619 static int ext4_dir_open(struct inode * inode, struct file * filp)
620 {
621 if (IS_ENCRYPTED(inode))
622 return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
623 return 0;
624 }
625
ext4_release_dir(struct inode * inode,struct file * filp)626 static int ext4_release_dir(struct inode *inode, struct file *filp)
627 {
628 if (filp->private_data)
629 ext4_htree_free_dir_info(filp->private_data);
630
631 return 0;
632 }
633
ext4_check_all_de(struct inode * dir,struct buffer_head * bh,void * buf,int buf_size)634 int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
635 int buf_size)
636 {
637 struct ext4_dir_entry_2 *de;
638 int rlen;
639 unsigned int offset = 0;
640 char *top;
641
642 de = (struct ext4_dir_entry_2 *)buf;
643 top = buf + buf_size;
644 while ((char *) de < top) {
645 if (ext4_check_dir_entry(dir, NULL, de, bh,
646 buf, buf_size, offset))
647 return -EFSCORRUPTED;
648 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
649 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
650 offset += rlen;
651 }
652 if ((char *) de > top)
653 return -EFSCORRUPTED;
654
655 return 0;
656 }
657
658 const struct file_operations ext4_dir_operations = {
659 .llseek = ext4_dir_llseek,
660 .read = generic_read_dir,
661 .iterate_shared = ext4_readdir,
662 .unlocked_ioctl = ext4_ioctl,
663 #ifdef CONFIG_COMPAT
664 .compat_ioctl = ext4_compat_ioctl,
665 #endif
666 .fsync = ext4_sync_file,
667 .open = ext4_dir_open,
668 .release = ext4_release_dir,
669 };
670
671 #ifdef CONFIG_UNICODE
ext4_d_compare(const struct dentry * dentry,unsigned int len,const char * str,const struct qstr * name)672 static int ext4_d_compare(const struct dentry *dentry, unsigned int len,
673 const char *str, const struct qstr *name)
674 {
675 struct qstr qstr = {.name = str, .len = len };
676 struct inode *inode = dentry->d_parent->d_inode;
677
678 if (!IS_CASEFOLDED(inode) || !EXT4_SB(inode->i_sb)->s_encoding) {
679 if (len != name->len)
680 return -1;
681 return memcmp(str, name->name, len);
682 }
683
684 return ext4_ci_compare(inode, name, &qstr, false);
685 }
686
ext4_d_hash(const struct dentry * dentry,struct qstr * str)687 static int ext4_d_hash(const struct dentry *dentry, struct qstr *str)
688 {
689 const struct ext4_sb_info *sbi = EXT4_SB(dentry->d_sb);
690 const struct unicode_map *um = sbi->s_encoding;
691 unsigned char *norm;
692 int len, ret = 0;
693
694 if (!IS_CASEFOLDED(dentry->d_inode) || !um)
695 return 0;
696
697 norm = kmalloc(PATH_MAX, GFP_ATOMIC);
698 if (!norm)
699 return -ENOMEM;
700
701 len = utf8_casefold(um, str, norm, PATH_MAX);
702 if (len < 0) {
703 if (ext4_has_strict_mode(sbi))
704 ret = -EINVAL;
705 goto out;
706 }
707 str->hash = full_name_hash(dentry, norm, len);
708 out:
709 kfree(norm);
710 return ret;
711 }
712
713 const struct dentry_operations ext4_dentry_ops = {
714 .d_hash = ext4_d_hash,
715 .d_compare = ext4_d_compare,
716 };
717 #endif
718