1/*
2 * dir.c
3 *
4 * Copyright (c) 1999 Al Smith
5 */
6
7#include <linux/buffer_head.h>
8#include "efs.h"
9
10static int efs_readdir(struct file *, void *, filldir_t);
11
12const struct file_operations efs_dir_operations = {
13	.llseek		= generic_file_llseek,
14	.read		= generic_read_dir,
15	.readdir	= efs_readdir,
16};
17
18const struct 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_path.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	/* work out where this entry can be found */
37	block = filp->f_pos >> EFS_DIRBSIZE_BITS;
38
39	/* each block contains at most 256 slots */
40	slot  = filp->f_pos & 0xff;
41
42	/* look at all blocks */
43	while (block < inode->i_blocks) {
44		/* read the dir block */
45		bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
46
47		if (!bh) {
48			printk(KERN_ERR "EFS: readdir(): failed to read dir block %d\n", block);
49			break;
50		}
51
52		dirblock = (struct efs_dir *) bh->b_data;
53
54		if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
55			printk(KERN_ERR "EFS: readdir(): invalid directory block\n");
56			brelse(bh);
57			break;
58		}
59
60		while (slot < dirblock->slots) {
61			if (dirblock->space[slot] == 0) {
62				slot++;
63				continue;
64			}
65
66			dirslot  = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
67
68			inodenum = be32_to_cpu(dirslot->inode);
69			namelen  = dirslot->namelen;
70			nameptr  = dirslot->name;
71
72#ifdef DEBUG
73			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);
74#endif
75			if (namelen > 0) {
76				/* found the next entry */
77				filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
78
79				/* copy filename and data in dirslot */
80				filldir(dirent, nameptr, namelen, filp->f_pos, inodenum, DT_UNKNOWN);
81
82				/* sanity check */
83				if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) {
84					printk(KERN_WARNING "EFS: directory entry %d exceeds directory block\n", slot);
85					slot++;
86					continue;
87				}
88
89				/* store position of next slot */
90				if (++slot == dirblock->slots) {
91					slot = 0;
92					block++;
93				}
94				brelse(bh);
95				filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
96				goto out;
97			}
98			slot++;
99		}
100		brelse(bh);
101
102		slot = 0;
103		block++;
104	}
105
106	filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
107out:
108	return 0;
109}
110