1 /*
2 * dir.c
3 *
4 * Copyright (c) 1999 Al Smith
5 */
6
7 #include <linux/efs_fs.h>
8
9 static int efs_readdir(struct file *, void *, filldir_t);
10
11 struct file_operations efs_dir_operations = {
12 read: generic_read_dir,
13 readdir: efs_readdir,
14 };
15
16 struct inode_operations efs_dir_inode_operations = {
17 lookup: efs_lookup,
18 };
19
20 static int efs_readdir(struct file *filp, void *dirent, filldir_t filldir) {
21 struct inode *inode = filp->f_dentry->d_inode;
22 struct buffer_head *bh;
23
24 struct efs_dir *dirblock;
25 struct efs_dentry *dirslot;
26 efs_ino_t inodenum;
27 efs_block_t block;
28 int slot, namelen;
29 char *nameptr;
30
31 if (inode->i_size & (EFS_DIRBSIZE-1))
32 printk(KERN_WARNING "EFS: WARNING: readdir(): directory size not a multiple of EFS_DIRBSIZE\n");
33
34 /* work out where this entry can be found */
35 block = filp->f_pos >> EFS_DIRBSIZE_BITS;
36
37 /* each block contains at most 256 slots */
38 slot = filp->f_pos & 0xff;
39
40 /* look at all blocks */
41 while (block < inode->i_blocks) {
42 /* read the dir block */
43 bh = bread(inode->i_dev, efs_bmap(inode, block), EFS_DIRBSIZE);
44
45 if (!bh) {
46 printk(KERN_ERR "EFS: readdir(): failed to read dir block %d\n", block);
47 break;
48 }
49
50 dirblock = (struct efs_dir *) bh->b_data;
51
52 if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
53 printk(KERN_ERR "EFS: readdir(): invalid directory block\n");
54 brelse(bh);
55 break;
56 }
57
58 while (slot < dirblock->slots) {
59 if (dirblock->space[slot] == 0) {
60 slot++;
61 continue;
62 }
63
64 dirslot = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
65
66 inodenum = be32_to_cpu(dirslot->inode);
67 namelen = dirslot->namelen;
68 nameptr = dirslot->name;
69
70 #ifdef DEBUG
71 printk(KERN_DEBUG "EFS: readdir(): block %d slot %d/%d: inode %u, name \"%s\", namelen %u\n", block, slot, dirblock->slots-1, inodenum, nameptr, namelen);
72 #endif
73 if (namelen > 0) {
74 /* found the next entry */
75 filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
76
77 /* copy filename and data in dirslot */
78 filldir(dirent, nameptr, namelen, filp->f_pos, inodenum, DT_UNKNOWN);
79
80 /* sanity check */
81 if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) {
82 printk(KERN_WARNING "EFS: directory entry %d exceeds directory block\n", slot);
83 slot++;
84 continue;
85 }
86
87 /* store position of next slot */
88 if (++slot == dirblock->slots) {
89 slot = 0;
90 block++;
91 }
92 brelse(bh);
93 filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
94 return 0;
95 }
96 slot++;
97 }
98 brelse(bh);
99
100 slot = 0;
101 block++;
102 }
103
104 filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
105 return 0;
106 }
107
108
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