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/jbd2.h>
26 #include <linux/ext4_fs.h>
27 #include <linux/buffer_head.h>
28 #include <linux/slab.h>
29 #include <linux/rbtree.h>
31 static unsigned char ext4_filetype_table
[] = {
32 DT_UNKNOWN
, DT_REG
, DT_DIR
, DT_CHR
, DT_BLK
, DT_FIFO
, DT_SOCK
, DT_LNK
35 static int ext4_readdir(struct file
*, void *, filldir_t
);
36 static int ext4_dx_readdir(struct file
* filp
,
37 void * dirent
, filldir_t filldir
);
38 static int ext4_release_dir (struct inode
* inode
,
41 const struct file_operations ext4_dir_operations
= {
42 .llseek
= generic_file_llseek
,
43 .read
= generic_read_dir
,
44 .readdir
= ext4_readdir
, /* we take BKL. needed?*/
45 .ioctl
= ext4_ioctl
, /* BKL held */
47 .compat_ioctl
= ext4_compat_ioctl
,
49 .fsync
= ext4_sync_file
, /* BKL held */
50 .release
= ext4_release_dir
,
54 static unsigned char get_dtype(struct super_block
*sb
, int filetype
)
56 if (!EXT4_HAS_INCOMPAT_FEATURE(sb
, EXT4_FEATURE_INCOMPAT_FILETYPE
) ||
57 (filetype
>= EXT4_FT_MAX
))
60 return (ext4_filetype_table
[filetype
]);
64 int ext4_check_dir_entry (const char * function
, struct inode
* dir
,
65 struct ext4_dir_entry_2
* de
,
66 struct buffer_head
* bh
,
69 const char * error_msg
= NULL
;
70 const int rlen
= ext4_rec_len_from_disk(de
->rec_len
);
72 if (rlen
< EXT4_DIR_REC_LEN(1))
73 error_msg
= "rec_len is smaller than minimal";
74 else if (rlen
% 4 != 0)
75 error_msg
= "rec_len % 4 != 0";
76 else if (rlen
< EXT4_DIR_REC_LEN(de
->name_len
))
77 error_msg
= "rec_len is too small for name_len";
78 else if (((char *) de
- bh
->b_data
) + rlen
> dir
->i_sb
->s_blocksize
)
79 error_msg
= "directory entry across blocks";
80 else if (le32_to_cpu(de
->inode
) >
81 le32_to_cpu(EXT4_SB(dir
->i_sb
)->s_es
->s_inodes_count
))
82 error_msg
= "inode out of bounds";
84 if (error_msg
!= NULL
)
85 ext4_error (dir
->i_sb
, function
,
86 "bad entry in directory #%lu: %s - "
87 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
88 dir
->i_ino
, error_msg
, offset
,
89 (unsigned long) le32_to_cpu(de
->inode
),
91 return error_msg
== NULL
? 1 : 0;
94 static int ext4_readdir(struct file
* filp
,
95 void * dirent
, filldir_t filldir
)
100 struct ext4_dir_entry_2
*de
;
101 struct super_block
*sb
;
103 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
108 if (EXT4_HAS_COMPAT_FEATURE(inode
->i_sb
,
109 EXT4_FEATURE_COMPAT_DIR_INDEX
) &&
110 ((EXT4_I(inode
)->i_flags
& EXT4_INDEX_FL
) ||
111 ((inode
->i_size
>> sb
->s_blocksize_bits
) == 1))) {
112 err
= ext4_dx_readdir(filp
, dirent
, filldir
);
113 if (err
!= ERR_BAD_DX_DIR
) {
118 * We don't set the inode dirty flag since it's not
119 * critical that it get flushed back to the disk.
121 EXT4_I(filp
->f_path
.dentry
->d_inode
)->i_flags
&= ~EXT4_INDEX_FL
;
124 offset
= filp
->f_pos
& (sb
->s_blocksize
- 1);
126 while (!error
&& !stored
&& filp
->f_pos
< inode
->i_size
) {
127 ext4_lblk_t blk
= filp
->f_pos
>> EXT4_BLOCK_SIZE_BITS(sb
);
128 struct buffer_head map_bh
;
129 struct buffer_head
*bh
= NULL
;
132 err
= ext4_get_blocks_wrap(NULL
, inode
, blk
, 1, &map_bh
, 0, 0);
134 pgoff_t index
= map_bh
.b_blocknr
>>
135 (PAGE_CACHE_SHIFT
- inode
->i_blkbits
);
136 if (!ra_has_index(&filp
->f_ra
, index
))
137 page_cache_sync_readahead(
138 sb
->s_bdev
->bd_inode
->i_mapping
,
141 filp
->f_ra
.prev_pos
= (loff_t
)index
<< PAGE_CACHE_SHIFT
;
142 bh
= ext4_bread(NULL
, inode
, blk
, 0, &err
);
146 * We ignore I/O errors on directories so users have a chance
147 * of recovering data when there's a bad sector
150 ext4_error (sb
, "ext4_readdir",
151 "directory #%lu contains a hole at offset %lu",
152 inode
->i_ino
, (unsigned long)filp
->f_pos
);
153 /* corrupt size? Maybe no more blocks to read */
154 if (filp
->f_pos
> inode
->i_blocks
<< 9)
156 filp
->f_pos
+= sb
->s_blocksize
- offset
;
161 /* If the dir block has changed since the last call to
162 * readdir(2), then we might be pointing to an invalid
163 * dirent right now. Scan from the start of the block
165 if (filp
->f_version
!= inode
->i_version
) {
166 for (i
= 0; i
< sb
->s_blocksize
&& i
< offset
; ) {
167 de
= (struct ext4_dir_entry_2
*)
169 /* It's too expensive to do a full
170 * dirent test each time round this
171 * loop, but we do have to test at
172 * least that it is non-zero. A
173 * failure will be detected in the
174 * dirent test below. */
175 if (ext4_rec_len_from_disk(de
->rec_len
)
176 < EXT4_DIR_REC_LEN(1))
178 i
+= ext4_rec_len_from_disk(de
->rec_len
);
181 filp
->f_pos
= (filp
->f_pos
& ~(sb
->s_blocksize
- 1))
183 filp
->f_version
= inode
->i_version
;
186 while (!error
&& filp
->f_pos
< inode
->i_size
187 && offset
< sb
->s_blocksize
) {
188 de
= (struct ext4_dir_entry_2
*) (bh
->b_data
+ offset
);
189 if (!ext4_check_dir_entry ("ext4_readdir", inode
, de
,
192 * On error, skip the f_pos to the next block
194 filp
->f_pos
= (filp
->f_pos
|
195 (sb
->s_blocksize
- 1)) + 1;
200 offset
+= ext4_rec_len_from_disk(de
->rec_len
);
201 if (le32_to_cpu(de
->inode
)) {
202 /* We might block in the next section
203 * if the data destination is
204 * currently swapped out. So, use a
205 * version stamp to detect whether or
206 * not the directory has been modified
207 * during the copy operation.
209 u64 version
= filp
->f_version
;
211 error
= filldir(dirent
, de
->name
,
214 le32_to_cpu(de
->inode
),
215 get_dtype(sb
, de
->file_type
));
218 if (version
!= filp
->f_version
)
222 filp
->f_pos
+= ext4_rec_len_from_disk(de
->rec_len
);
232 * These functions convert from the major/minor hash to an f_pos
235 * Currently we only use major hash numer. This is unfortunate, but
236 * on 32-bit machines, the same VFS interface is used for lseek and
237 * llseek, so if we use the 64 bit offset, then the 32-bit versions of
238 * lseek/telldir/seekdir will blow out spectacularly, and from within
239 * the ext2 low-level routine, we don't know if we're being called by
240 * a 64-bit version of the system call or the 32-bit version of the
241 * system call. Worse yet, NFSv2 only allows for a 32-bit readdir
244 #define hash2pos(major, minor) (major >> 1)
245 #define pos2maj_hash(pos) ((pos << 1) & 0xffffffff)
246 #define pos2min_hash(pos) (0)
249 * This structure holds the nodes of the red-black tree used to store
250 * the directory entry in hash order.
255 struct rb_node rb_hash
;
264 * This functoin implements a non-recursive way of freeing all of the
265 * nodes in the red-black tree.
267 static void free_rb_tree_fname(struct rb_root
*root
)
269 struct rb_node
*n
= root
->rb_node
;
270 struct rb_node
*parent
;
274 /* Do the node's children first */
284 * The node has no children; free it, and then zero
285 * out parent's link to it. Finally go to the
286 * beginning of the loop and try to free the parent
289 parent
= rb_parent(n
);
290 fname
= rb_entry(n
, struct fname
, rb_hash
);
292 struct fname
* old
= fname
;
297 root
->rb_node
= NULL
;
298 else if (parent
->rb_left
== n
)
299 parent
->rb_left
= NULL
;
300 else if (parent
->rb_right
== n
)
301 parent
->rb_right
= NULL
;
304 root
->rb_node
= NULL
;
308 static struct dir_private_info
*create_dir_info(loff_t pos
)
310 struct dir_private_info
*p
;
312 p
= kmalloc(sizeof(struct dir_private_info
), GFP_KERNEL
);
315 p
->root
.rb_node
= NULL
;
317 p
->extra_fname
= NULL
;
319 p
->curr_hash
= pos2maj_hash(pos
);
320 p
->curr_minor_hash
= pos2min_hash(pos
);
325 void ext4_htree_free_dir_info(struct dir_private_info
*p
)
327 free_rb_tree_fname(&p
->root
);
332 * Given a directory entry, enter it into the fname rb tree.
334 int ext4_htree_store_dirent(struct file
*dir_file
, __u32 hash
,
336 struct ext4_dir_entry_2
*dirent
)
338 struct rb_node
**p
, *parent
= NULL
;
339 struct fname
* fname
, *new_fn
;
340 struct dir_private_info
*info
;
343 info
= (struct dir_private_info
*) dir_file
->private_data
;
344 p
= &info
->root
.rb_node
;
346 /* Create and allocate the fname structure */
347 len
= sizeof(struct fname
) + dirent
->name_len
+ 1;
348 new_fn
= kzalloc(len
, GFP_KERNEL
);
352 new_fn
->minor_hash
= minor_hash
;
353 new_fn
->inode
= le32_to_cpu(dirent
->inode
);
354 new_fn
->name_len
= dirent
->name_len
;
355 new_fn
->file_type
= dirent
->file_type
;
356 memcpy(new_fn
->name
, dirent
->name
, dirent
->name_len
);
357 new_fn
->name
[dirent
->name_len
] = 0;
361 fname
= rb_entry(parent
, struct fname
, rb_hash
);
364 * If the hash and minor hash match up, then we put
365 * them on a linked list. This rarely happens...
367 if ((new_fn
->hash
== fname
->hash
) &&
368 (new_fn
->minor_hash
== fname
->minor_hash
)) {
369 new_fn
->next
= fname
->next
;
370 fname
->next
= new_fn
;
374 if (new_fn
->hash
< fname
->hash
)
376 else if (new_fn
->hash
> fname
->hash
)
378 else if (new_fn
->minor_hash
< fname
->minor_hash
)
380 else /* if (new_fn->minor_hash > fname->minor_hash) */
384 rb_link_node(&new_fn
->rb_hash
, parent
, p
);
385 rb_insert_color(&new_fn
->rb_hash
, &info
->root
);
392 * This is a helper function for ext4_dx_readdir. It calls filldir
393 * for all entres on the fname linked list. (Normally there is only
394 * one entry on the linked list, unless there are 62 bit hash collisions.)
396 static int call_filldir(struct file
* filp
, void * dirent
,
397 filldir_t filldir
, struct fname
*fname
)
399 struct dir_private_info
*info
= filp
->private_data
;
401 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
402 struct super_block
* sb
;
408 printk("call_filldir: called with null fname?!?\n");
411 curr_pos
= hash2pos(fname
->hash
, fname
->minor_hash
);
413 error
= filldir(dirent
, fname
->name
,
414 fname
->name_len
, curr_pos
,
416 get_dtype(sb
, fname
->file_type
));
418 filp
->f_pos
= curr_pos
;
419 info
->extra_fname
= fname
->next
;
427 static int ext4_dx_readdir(struct file
* filp
,
428 void * dirent
, filldir_t filldir
)
430 struct dir_private_info
*info
= filp
->private_data
;
431 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
436 info
= create_dir_info(filp
->f_pos
);
439 filp
->private_data
= info
;
442 if (filp
->f_pos
== EXT4_HTREE_EOF
)
445 /* Some one has messed with f_pos; reset the world */
446 if (info
->last_pos
!= filp
->f_pos
) {
447 free_rb_tree_fname(&info
->root
);
448 info
->curr_node
= NULL
;
449 info
->extra_fname
= NULL
;
450 info
->curr_hash
= pos2maj_hash(filp
->f_pos
);
451 info
->curr_minor_hash
= pos2min_hash(filp
->f_pos
);
455 * If there are any leftover names on the hash collision
456 * chain, return them first.
458 if (info
->extra_fname
&&
459 call_filldir(filp
, dirent
, filldir
, info
->extra_fname
))
462 if (!info
->curr_node
)
463 info
->curr_node
= rb_first(&info
->root
);
467 * Fill the rbtree if we have no more entries,
468 * or the inode has changed since we last read in the
471 if ((!info
->curr_node
) ||
472 (filp
->f_version
!= inode
->i_version
)) {
473 info
->curr_node
= NULL
;
474 free_rb_tree_fname(&info
->root
);
475 filp
->f_version
= inode
->i_version
;
476 ret
= ext4_htree_fill_tree(filp
, info
->curr_hash
,
477 info
->curr_minor_hash
,
482 filp
->f_pos
= EXT4_HTREE_EOF
;
485 info
->curr_node
= rb_first(&info
->root
);
488 fname
= rb_entry(info
->curr_node
, struct fname
, rb_hash
);
489 info
->curr_hash
= fname
->hash
;
490 info
->curr_minor_hash
= fname
->minor_hash
;
491 if (call_filldir(filp
, dirent
, filldir
, fname
))
494 info
->curr_node
= rb_next(info
->curr_node
);
495 if (!info
->curr_node
) {
496 if (info
->next_hash
== ~0) {
497 filp
->f_pos
= EXT4_HTREE_EOF
;
500 info
->curr_hash
= info
->next_hash
;
501 info
->curr_minor_hash
= 0;
505 info
->last_pos
= filp
->f_pos
;
509 static int ext4_release_dir (struct inode
* inode
, struct file
* filp
)
511 if (filp
->private_data
)
512 ext4_htree_free_dir_info(filp
->private_data
);