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)
11 * linux/fs/minix/dir.c
13 * Copyright (C) 1991, 1992 Linus Torvalds
15 * ext4 directory handling functions
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
20 * Hash Tree Directory indexing (c) 2001 Daniel Phillips
25 #include <linux/buffer_head.h>
26 #include <linux/slab.h>
30 static int ext4_dx_readdir(struct file
*, struct dir_context
*);
33 * Check if the given dir-inode refers to an htree-indexed directory
34 * (or a directory which could potentially get converted to use htree
37 * Return 1 if it is a dx dir, 0 if not
39 static int is_dx_dir(struct inode
*inode
)
41 struct super_block
*sb
= inode
->i_sb
;
43 if (ext4_has_feature_dir_index(inode
->i_sb
) &&
44 ((ext4_test_inode_flag(inode
, EXT4_INODE_INDEX
)) ||
45 ((inode
->i_size
>> sb
->s_blocksize_bits
) == 1) ||
46 ext4_has_inline_data(inode
)))
53 * Return 0 if the directory entry is OK, and 1 if there is a problem
55 * Note: this is the opposite of what ext2 and ext3 historically returned...
57 * bh passed here can be an inode block or a dir data block, depending
58 * on the inode inline data flag.
60 int __ext4_check_dir_entry(const char *function
, unsigned int line
,
61 struct inode
*dir
, struct file
*filp
,
62 struct ext4_dir_entry_2
*de
,
63 struct buffer_head
*bh
, char *buf
, int size
,
66 const char *error_msg
= NULL
;
67 const int rlen
= ext4_rec_len_from_disk(de
->rec_len
,
68 dir
->i_sb
->s_blocksize
);
70 if (unlikely(rlen
< EXT4_DIR_REC_LEN(1)))
71 error_msg
= "rec_len is smaller than minimal";
72 else if (unlikely(rlen
% 4 != 0))
73 error_msg
= "rec_len % 4 != 0";
74 else if (unlikely(rlen
< EXT4_DIR_REC_LEN(de
->name_len
)))
75 error_msg
= "rec_len is too small for name_len";
76 else if (unlikely(((char *) de
- buf
) + rlen
> size
))
77 error_msg
= "directory entry across range";
78 else if (unlikely(le32_to_cpu(de
->inode
) >
79 le32_to_cpu(EXT4_SB(dir
->i_sb
)->s_es
->s_inodes_count
)))
80 error_msg
= "inode out of bounds";
85 ext4_error_file(filp
, function
, line
, bh
->b_blocknr
,
86 "bad entry in directory: %s - offset=%u(%u), "
87 "inode=%u, rec_len=%d, name_len=%d",
88 error_msg
, (unsigned) (offset
% size
),
89 offset
, le32_to_cpu(de
->inode
),
92 ext4_error_inode(dir
, function
, line
, bh
->b_blocknr
,
93 "bad entry in directory: %s - offset=%u(%u), "
94 "inode=%u, rec_len=%d, name_len=%d",
95 error_msg
, (unsigned) (offset
% size
),
96 offset
, le32_to_cpu(de
->inode
),
102 static int ext4_readdir(struct file
*file
, struct dir_context
*ctx
)
106 struct ext4_dir_entry_2
*de
;
108 struct inode
*inode
= file_inode(file
);
109 struct super_block
*sb
= inode
->i_sb
;
110 struct buffer_head
*bh
= NULL
;
111 int dir_has_error
= 0;
112 struct ext4_str fname_crypto_str
= {.name
= NULL
, .len
= 0};
114 if (ext4_encrypted_inode(inode
)) {
115 err
= ext4_get_encryption_info(inode
);
116 if (err
&& err
!= -ENOKEY
)
120 if (is_dx_dir(inode
)) {
121 err
= ext4_dx_readdir(file
, ctx
);
122 if (err
!= ERR_BAD_DX_DIR
) {
126 * We don't set the inode dirty flag since it's not
127 * critical that it get flushed back to the disk.
129 ext4_clear_inode_flag(file_inode(file
),
133 if (ext4_has_inline_data(inode
)) {
134 int has_inline_data
= 1;
135 err
= ext4_read_inline_dir(file
, ctx
,
141 if (ext4_encrypted_inode(inode
)) {
142 err
= ext4_fname_crypto_alloc_buffer(inode
, EXT4_NAME_LEN
,
148 offset
= ctx
->pos
& (sb
->s_blocksize
- 1);
150 while (ctx
->pos
< inode
->i_size
) {
151 struct ext4_map_blocks map
;
153 if (fatal_signal_pending(current
)) {
158 map
.m_lblk
= ctx
->pos
>> EXT4_BLOCK_SIZE_BITS(sb
);
160 err
= ext4_map_blocks(NULL
, inode
, &map
, 0);
162 pgoff_t index
= map
.m_pblk
>>
163 (PAGE_SHIFT
- inode
->i_blkbits
);
164 if (!ra_has_index(&file
->f_ra
, index
))
165 page_cache_sync_readahead(
166 sb
->s_bdev
->bd_inode
->i_mapping
,
169 file
->f_ra
.prev_pos
= (loff_t
)index
<< PAGE_SHIFT
;
170 bh
= ext4_bread(NULL
, inode
, map
.m_lblk
, 0);
179 if (!dir_has_error
) {
180 EXT4_ERROR_FILE(file
, 0,
181 "directory contains a "
182 "hole at offset %llu",
183 (unsigned long long) ctx
->pos
);
186 /* corrupt size? Maybe no more blocks to read */
187 if (ctx
->pos
> inode
->i_blocks
<< 9)
189 ctx
->pos
+= sb
->s_blocksize
- offset
;
193 /* Check the checksum */
194 if (!buffer_verified(bh
) &&
195 !ext4_dirent_csum_verify(inode
,
196 (struct ext4_dir_entry
*)bh
->b_data
)) {
197 EXT4_ERROR_FILE(file
, 0, "directory fails checksum "
199 (unsigned long long)ctx
->pos
);
200 ctx
->pos
+= sb
->s_blocksize
- offset
;
205 set_buffer_verified(bh
);
207 /* If the dir block has changed since the last call to
208 * readdir(2), then we might be pointing to an invalid
209 * dirent right now. Scan from the start of the block
211 if (file
->f_version
!= inode
->i_version
) {
212 for (i
= 0; i
< sb
->s_blocksize
&& i
< offset
; ) {
213 de
= (struct ext4_dir_entry_2
*)
215 /* It's too expensive to do a full
216 * dirent test each time round this
217 * loop, but we do have to test at
218 * least that it is non-zero. A
219 * failure will be detected in the
220 * dirent test below. */
221 if (ext4_rec_len_from_disk(de
->rec_len
,
222 sb
->s_blocksize
) < EXT4_DIR_REC_LEN(1))
224 i
+= ext4_rec_len_from_disk(de
->rec_len
,
228 ctx
->pos
= (ctx
->pos
& ~(sb
->s_blocksize
- 1))
230 file
->f_version
= inode
->i_version
;
233 while (ctx
->pos
< inode
->i_size
234 && offset
< sb
->s_blocksize
) {
235 de
= (struct ext4_dir_entry_2
*) (bh
->b_data
+ offset
);
236 if (ext4_check_dir_entry(inode
, file
, de
, bh
,
237 bh
->b_data
, bh
->b_size
,
240 * On error, skip to the next block
242 ctx
->pos
= (ctx
->pos
|
243 (sb
->s_blocksize
- 1)) + 1;
246 offset
+= ext4_rec_len_from_disk(de
->rec_len
,
248 if (le32_to_cpu(de
->inode
)) {
249 if (!ext4_encrypted_inode(inode
)) {
250 if (!dir_emit(ctx
, de
->name
,
252 le32_to_cpu(de
->inode
),
253 get_dtype(sb
, de
->file_type
)))
256 int save_len
= fname_crypto_str
.len
;
258 /* Directory is encrypted */
259 err
= ext4_fname_disk_to_usr(inode
,
260 NULL
, de
, &fname_crypto_str
);
261 fname_crypto_str
.len
= save_len
;
265 fname_crypto_str
.name
, err
,
266 le32_to_cpu(de
->inode
),
267 get_dtype(sb
, de
->file_type
)))
271 ctx
->pos
+= ext4_rec_len_from_disk(de
->rec_len
,
274 if ((ctx
->pos
< inode
->i_size
) && !dir_relax_shared(inode
))
283 #ifdef CONFIG_EXT4_FS_ENCRYPTION
284 ext4_fname_crypto_free_buffer(&fname_crypto_str
);
290 static inline int is_32bit_api(void)
293 return in_compat_syscall();
295 return (BITS_PER_LONG
== 32);
300 * These functions convert from the major/minor hash to an f_pos
301 * value for dx directories
303 * Upper layer (for example NFS) should specify FMODE_32BITHASH or
304 * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
305 * directly on both 32-bit and 64-bit nodes, under such case, neither
306 * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
308 static inline loff_t
hash2pos(struct file
*filp
, __u32 major
, __u32 minor
)
310 if ((filp
->f_mode
& FMODE_32BITHASH
) ||
311 (!(filp
->f_mode
& FMODE_64BITHASH
) && is_32bit_api()))
314 return ((__u64
)(major
>> 1) << 32) | (__u64
)minor
;
317 static inline __u32
pos2maj_hash(struct file
*filp
, loff_t pos
)
319 if ((filp
->f_mode
& FMODE_32BITHASH
) ||
320 (!(filp
->f_mode
& FMODE_64BITHASH
) && is_32bit_api()))
321 return (pos
<< 1) & 0xffffffff;
323 return ((pos
>> 32) << 1) & 0xffffffff;
326 static inline __u32
pos2min_hash(struct file
*filp
, loff_t pos
)
328 if ((filp
->f_mode
& FMODE_32BITHASH
) ||
329 (!(filp
->f_mode
& FMODE_64BITHASH
) && is_32bit_api()))
332 return pos
& 0xffffffff;
336 * Return 32- or 64-bit end-of-file for dx directories
338 static inline loff_t
ext4_get_htree_eof(struct file
*filp
)
340 if ((filp
->f_mode
& FMODE_32BITHASH
) ||
341 (!(filp
->f_mode
& FMODE_64BITHASH
) && is_32bit_api()))
342 return EXT4_HTREE_EOF_32BIT
;
344 return EXT4_HTREE_EOF_64BIT
;
349 * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
350 * directories, where the "offset" is in terms of the filename hash
351 * value instead of the byte offset.
353 * Because we may return a 64-bit hash that is well beyond offset limits,
354 * we need to pass the max hash as the maximum allowable offset in
355 * the htree directory case.
357 * For non-htree, ext4_llseek already chooses the proper max offset.
359 static loff_t
ext4_dir_llseek(struct file
*file
, loff_t offset
, int whence
)
361 struct inode
*inode
= file
->f_mapping
->host
;
362 int dx_dir
= is_dx_dir(inode
);
363 loff_t htree_max
= ext4_get_htree_eof(file
);
366 return generic_file_llseek_size(file
, offset
, whence
,
367 htree_max
, htree_max
);
369 return ext4_llseek(file
, offset
, whence
);
373 * This structure holds the nodes of the red-black tree used to store
374 * the directory entry in hash order.
379 struct rb_node rb_hash
;
388 * This functoin implements a non-recursive way of freeing all of the
389 * nodes in the red-black tree.
391 static void free_rb_tree_fname(struct rb_root
*root
)
393 struct fname
*fname
, *next
;
395 rbtree_postorder_for_each_entry_safe(fname
, next
, root
, rb_hash
)
397 struct fname
*old
= fname
;
406 static struct dir_private_info
*ext4_htree_create_dir_info(struct file
*filp
,
409 struct dir_private_info
*p
;
411 p
= kzalloc(sizeof(struct dir_private_info
), GFP_KERNEL
);
414 p
->curr_hash
= pos2maj_hash(filp
, pos
);
415 p
->curr_minor_hash
= pos2min_hash(filp
, pos
);
419 void ext4_htree_free_dir_info(struct dir_private_info
*p
)
421 free_rb_tree_fname(&p
->root
);
426 * Given a directory entry, enter it into the fname rb tree.
428 * When filename encryption is enabled, the dirent will hold the
429 * encrypted filename, while the htree will hold decrypted filename.
430 * The decrypted filename is passed in via ent_name. parameter.
432 int ext4_htree_store_dirent(struct file
*dir_file
, __u32 hash
,
434 struct ext4_dir_entry_2
*dirent
,
435 struct ext4_str
*ent_name
)
437 struct rb_node
**p
, *parent
= NULL
;
438 struct fname
*fname
, *new_fn
;
439 struct dir_private_info
*info
;
442 info
= dir_file
->private_data
;
443 p
= &info
->root
.rb_node
;
445 /* Create and allocate the fname structure */
446 len
= sizeof(struct fname
) + ent_name
->len
+ 1;
447 new_fn
= kzalloc(len
, GFP_KERNEL
);
451 new_fn
->minor_hash
= minor_hash
;
452 new_fn
->inode
= le32_to_cpu(dirent
->inode
);
453 new_fn
->name_len
= ent_name
->len
;
454 new_fn
->file_type
= dirent
->file_type
;
455 memcpy(new_fn
->name
, ent_name
->name
, ent_name
->len
);
456 new_fn
->name
[ent_name
->len
] = 0;
460 fname
= rb_entry(parent
, struct fname
, rb_hash
);
463 * If the hash and minor hash match up, then we put
464 * them on a linked list. This rarely happens...
466 if ((new_fn
->hash
== fname
->hash
) &&
467 (new_fn
->minor_hash
== fname
->minor_hash
)) {
468 new_fn
->next
= fname
->next
;
469 fname
->next
= new_fn
;
473 if (new_fn
->hash
< fname
->hash
)
475 else if (new_fn
->hash
> fname
->hash
)
477 else if (new_fn
->minor_hash
< fname
->minor_hash
)
479 else /* if (new_fn->minor_hash > fname->minor_hash) */
483 rb_link_node(&new_fn
->rb_hash
, parent
, p
);
484 rb_insert_color(&new_fn
->rb_hash
, &info
->root
);
491 * This is a helper function for ext4_dx_readdir. It calls filldir
492 * for all entres on the fname linked list. (Normally there is only
493 * one entry on the linked list, unless there are 62 bit hash collisions.)
495 static int call_filldir(struct file
*file
, struct dir_context
*ctx
,
498 struct dir_private_info
*info
= file
->private_data
;
499 struct inode
*inode
= file_inode(file
);
500 struct super_block
*sb
= inode
->i_sb
;
503 ext4_msg(sb
, KERN_ERR
, "%s:%d: inode #%lu: comm %s: "
504 "called with null fname?!?", __func__
, __LINE__
,
505 inode
->i_ino
, current
->comm
);
508 ctx
->pos
= hash2pos(file
, fname
->hash
, fname
->minor_hash
);
510 if (!dir_emit(ctx
, fname
->name
,
513 get_dtype(sb
, fname
->file_type
))) {
514 info
->extra_fname
= fname
;
522 static int ext4_dx_readdir(struct file
*file
, struct dir_context
*ctx
)
524 struct dir_private_info
*info
= file
->private_data
;
525 struct inode
*inode
= file_inode(file
);
530 info
= ext4_htree_create_dir_info(file
, ctx
->pos
);
533 file
->private_data
= info
;
536 if (ctx
->pos
== ext4_get_htree_eof(file
))
539 /* Some one has messed with f_pos; reset the world */
540 if (info
->last_pos
!= ctx
->pos
) {
541 free_rb_tree_fname(&info
->root
);
542 info
->curr_node
= NULL
;
543 info
->extra_fname
= NULL
;
544 info
->curr_hash
= pos2maj_hash(file
, ctx
->pos
);
545 info
->curr_minor_hash
= pos2min_hash(file
, ctx
->pos
);
549 * If there are any leftover names on the hash collision
550 * chain, return them first.
552 if (info
->extra_fname
) {
553 if (call_filldir(file
, ctx
, info
->extra_fname
))
555 info
->extra_fname
= NULL
;
557 } else if (!info
->curr_node
)
558 info
->curr_node
= rb_first(&info
->root
);
562 * Fill the rbtree if we have no more entries,
563 * or the inode has changed since we last read in the
566 if ((!info
->curr_node
) ||
567 (file
->f_version
!= inode
->i_version
)) {
568 info
->curr_node
= NULL
;
569 free_rb_tree_fname(&info
->root
);
570 file
->f_version
= inode
->i_version
;
571 ret
= ext4_htree_fill_tree(file
, info
->curr_hash
,
572 info
->curr_minor_hash
,
577 ctx
->pos
= ext4_get_htree_eof(file
);
580 info
->curr_node
= rb_first(&info
->root
);
583 fname
= rb_entry(info
->curr_node
, struct fname
, rb_hash
);
584 info
->curr_hash
= fname
->hash
;
585 info
->curr_minor_hash
= fname
->minor_hash
;
586 if (call_filldir(file
, ctx
, fname
))
589 info
->curr_node
= rb_next(info
->curr_node
);
590 if (info
->curr_node
) {
591 fname
= rb_entry(info
->curr_node
, struct fname
,
593 info
->curr_hash
= fname
->hash
;
594 info
->curr_minor_hash
= fname
->minor_hash
;
596 if (info
->next_hash
== ~0) {
597 ctx
->pos
= ext4_get_htree_eof(file
);
600 info
->curr_hash
= info
->next_hash
;
601 info
->curr_minor_hash
= 0;
605 info
->last_pos
= ctx
->pos
;
609 static int ext4_dir_open(struct inode
* inode
, struct file
* filp
)
611 if (ext4_encrypted_inode(inode
))
612 return ext4_get_encryption_info(inode
) ? -EACCES
: 0;
616 static int ext4_release_dir(struct inode
*inode
, struct file
*filp
)
618 if (filp
->private_data
)
619 ext4_htree_free_dir_info(filp
->private_data
);
624 int ext4_check_all_de(struct inode
*dir
, struct buffer_head
*bh
, void *buf
,
627 struct ext4_dir_entry_2
*de
;
629 unsigned int offset
= 0;
632 de
= (struct ext4_dir_entry_2
*)buf
;
633 top
= buf
+ buf_size
;
634 while ((char *) de
< top
) {
635 if (ext4_check_dir_entry(dir
, NULL
, de
, bh
,
636 buf
, buf_size
, offset
))
637 return -EFSCORRUPTED
;
638 nlen
= EXT4_DIR_REC_LEN(de
->name_len
);
639 rlen
= ext4_rec_len_from_disk(de
->rec_len
, buf_size
);
640 de
= (struct ext4_dir_entry_2
*)((char *)de
+ rlen
);
643 if ((char *) de
> top
)
644 return -EFSCORRUPTED
;
649 const struct file_operations ext4_dir_operations
= {
650 .llseek
= ext4_dir_llseek
,
651 .read
= generic_read_dir
,
652 .iterate_shared
= ext4_readdir
,
653 .unlocked_ioctl
= ext4_ioctl
,
655 .compat_ioctl
= ext4_compat_ioctl
,
657 .fsync
= ext4_sync_file
,
658 .open
= ext4_dir_open
,
659 .release
= ext4_release_dir
,