This source file includes following definitions.
- ext2_dir_read
- ext2_check_dir_entry
- ext2_readdir
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17 #include <asm/segment.h>
18
19 #include <linux/errno.h>
20 #include <linux/fs.h>
21 #include <linux/ext2_fs.h>
22 #include <linux/sched.h>
23 #include <linux/stat.h>
24
25 static int ext2_dir_read (struct inode * inode, struct file * filp,
26 char * buf, int count)
27 {
28 return -EISDIR;
29 }
30
31 static int ext2_readdir (struct inode *, struct file *, struct dirent *, int);
32
33 static struct file_operations ext2_dir_operations = {
34 NULL,
35 ext2_dir_read,
36 NULL,
37 ext2_readdir,
38 NULL,
39 ext2_ioctl,
40 NULL,
41 NULL,
42 NULL,
43 file_fsync
44 };
45
46
47
48
49 struct inode_operations ext2_dir_inode_operations = {
50 &ext2_dir_operations,
51 ext2_create,
52 ext2_lookup,
53 ext2_link,
54 ext2_unlink,
55 ext2_symlink,
56 ext2_mkdir,
57 ext2_rmdir,
58 ext2_mknod,
59 ext2_rename,
60 NULL,
61 NULL,
62 NULL,
63 ext2_truncate,
64 ext2_permission
65 };
66
67 int ext2_check_dir_entry (char * function, struct inode * dir,
68 struct ext2_dir_entry * de, struct buffer_head * bh,
69 unsigned long offset)
70 {
71 char * error_msg = NULL;
72
73 if (de->rec_len < EXT2_DIR_REC_LEN(1))
74 error_msg = "rec_len is smaller than minimal";
75 else if (de->rec_len % 4 != 0)
76 error_msg = "rec_len % 4 != 0";
77 else if (de->rec_len < EXT2_DIR_REC_LEN(de->name_len))
78 error_msg = "rec_len is too small for name_len";
79 else if (dir && ((char *) de - bh->b_data) + de->rec_len >
80 dir->i_sb->s_blocksize)
81 error_msg = "directory entry across blocks";
82
83 if (error_msg != NULL)
84 ext2_error (dir->i_sb, function, "bad directory entry: %s\n"
85 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
86 error_msg, offset, de->inode, de->rec_len,
87 de->name_len);
88 return error_msg == NULL ? 1 : 0;
89 }
90
91 static int ext2_readdir (struct inode * inode, struct file * filp,
92 struct dirent * dirent, int count)
93 {
94 unsigned long offset, blk;
95 int i, num;
96 struct buffer_head * bh, * tmp, * bha[16];
97 struct ext2_dir_entry * de;
98 struct super_block * sb;
99 int err;
100
101 if (!inode || !S_ISDIR(inode->i_mode))
102 return -EBADF;
103 sb = inode->i_sb;
104 while (filp->f_pos < inode->i_size) {
105 offset = filp->f_pos & (sb->s_blocksize - 1);
106 blk = (filp->f_pos) >> EXT2_BLOCK_SIZE_BITS(sb);
107 bh = ext2_bread (inode, blk, 0, &err);
108 if (!bh) {
109 filp->f_pos += sb->s_blocksize - offset;
110 continue;
111 }
112
113
114
115
116 if (!offset) {
117 for (i = 16 >> (EXT2_BLOCK_SIZE_BITS(sb) - 9), num = 0;
118 i > 0; i--) {
119 tmp = ext2_getblk (inode, ++blk, 0, &err);
120 if (tmp && !tmp->b_uptodate && !tmp->b_lock)
121 bha[num++] = tmp;
122 else
123 brelse (tmp);
124 }
125 if (num) {
126 ll_rw_block (READA, num, bha);
127 for (i = 0; i < num; i++)
128 brelse (bha[i]);
129 }
130 }
131
132 de = (struct ext2_dir_entry *) (offset + bh->b_data);
133 while (offset < sb->s_blocksize && filp->f_pos < inode->i_size) {
134 if (!ext2_check_dir_entry ("ext2_readdir", inode, de,
135 bh, offset)) {
136 brelse (bh);
137 return 0;
138 }
139 offset += de->rec_len;
140 filp->f_pos += de->rec_len;
141 if (de->inode) {
142 memcpy_tofs (dirent->d_name, de->name,
143 de->name_len);
144 put_fs_long (de->inode, &dirent->d_ino);
145 put_fs_byte (0, de->name_len + dirent->d_name);
146 put_fs_word (de->name_len, &dirent->d_reclen);
147 #ifndef DONT_USE_DCACHE
148 ext2_dcache_add (inode->i_dev, inode->i_ino,
149 de->name, de->name_len,
150 de->inode);
151 #endif
152 i = de->name_len;
153 brelse (bh);
154 if (!IS_RDONLY(inode)) {
155 inode->i_atime = CURRENT_TIME;
156 inode->i_dirt = 1;
157 }
158 return i;
159 }
160 de = (struct ext2_dir_entry *) ((char *) de +
161 de->rec_len);
162 }
163 brelse (bh);
164 }
165 if (!IS_RDONLY(inode)) {
166 inode->i_atime = CURRENT_TIME;
167 inode->i_dirt = 1;
168 }
169 return 0;
170 }