blob: 17f5b2d3c16a7071a18010926d574a26046569b1 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * dir.c
3 *
4 * Copyright (c) 1999 Al Smith
5 */
6
7#include <linux/buffer_head.h>
8#include <linux/efs_fs.h>
9#include <linux/smp_lock.h>
10
11static int efs_readdir(struct file *, void *, filldir_t);
12
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080013const struct file_operations efs_dir_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070014 .read = generic_read_dir,
15 .readdir = efs_readdir,
16};
17
18struct inode_operations efs_dir_inode_operations = {
19 .lookup = efs_lookup,
20};
21
22static int efs_readdir(struct file *filp, void *dirent, filldir_t filldir) {
23 struct inode *inode = filp->f_dentry->d_inode;
24 struct buffer_head *bh;
25
26 struct efs_dir *dirblock;
27 struct efs_dentry *dirslot;
28 efs_ino_t inodenum;
29 efs_block_t block;
30 int slot, namelen;
31 char *nameptr;
32
33 if (inode->i_size & (EFS_DIRBSIZE-1))
34 printk(KERN_WARNING "EFS: WARNING: readdir(): directory size not a multiple of EFS_DIRBSIZE\n");
35
36 lock_kernel();
37
38 /* work out where this entry can be found */
39 block = filp->f_pos >> EFS_DIRBSIZE_BITS;
40
41 /* each block contains at most 256 slots */
42 slot = filp->f_pos & 0xff;
43
44 /* look at all blocks */
45 while (block < inode->i_blocks) {
46 /* read the dir block */
47 bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
48
49 if (!bh) {
50 printk(KERN_ERR "EFS: readdir(): failed to read dir block %d\n", block);
51 break;
52 }
53
54 dirblock = (struct efs_dir *) bh->b_data;
55
56 if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
57 printk(KERN_ERR "EFS: readdir(): invalid directory block\n");
58 brelse(bh);
59 break;
60 }
61
62 while (slot < dirblock->slots) {
63 if (dirblock->space[slot] == 0) {
64 slot++;
65 continue;
66 }
67
68 dirslot = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
69
70 inodenum = be32_to_cpu(dirslot->inode);
71 namelen = dirslot->namelen;
72 nameptr = dirslot->name;
73
74#ifdef DEBUG
75 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);
76#endif
77 if (namelen > 0) {
78 /* found the next entry */
79 filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
80
81 /* copy filename and data in dirslot */
82 filldir(dirent, nameptr, namelen, filp->f_pos, inodenum, DT_UNKNOWN);
83
84 /* sanity check */
85 if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) {
86 printk(KERN_WARNING "EFS: directory entry %d exceeds directory block\n", slot);
87 slot++;
88 continue;
89 }
90
91 /* store position of next slot */
92 if (++slot == dirblock->slots) {
93 slot = 0;
94 block++;
95 }
96 brelse(bh);
97 filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
98 goto out;
99 }
100 slot++;
101 }
102 brelse(bh);
103
104 slot = 0;
105 block++;
106 }
107
108 filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
109out:
110 unlock_kernel();
111 return 0;
112}
113