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/*
 * dir.c
 *
 * Copyright (c) 1999 Al Smith
 */
 
#include <linux/buffer_head.h>
#include <linux/efs_fs.h>
#include <linux/smp_lock.h>
 
static int efs_readdir(struct file *, void *, filldir_t);
 
const struct file_operations efs_dir_operations = {
	.read		= generic_read_dir,
	.readdir	= efs_readdir,
};
 
const struct inode_operations efs_dir_inode_operations = {
	.lookup		= efs_lookup,
};
 
static int efs_readdir(struct file *filp, void *dirent, filldir_t filldir) {
	struct inode *inode = filp->f_path.dentry->d_inode;
	struct buffer_head *bh;
 
	struct efs_dir		*dirblock;
	struct efs_dentry	*dirslot;
	efs_ino_t		inodenum;
	efs_block_t		block;
	int			slot, namelen;
	char			*nameptr;
 
	if (inode->i_size & (EFS_DIRBSIZE-1))
		printk(KERN_WARNING "EFS: WARNING: readdir(): directory size not a multiple of EFS_DIRBSIZE\n");
 
	lock_kernel();
 
	/* work out where this entry can be found */
	block = filp->f_pos >> EFS_DIRBSIZE_BITS;
 
	/* each block contains at most 256 slots */
	slot  = filp->f_pos & 0xff;
 
	/* look at all blocks */
	while (block < inode->i_blocks) {
		/* read the dir block */
		bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
 
		if (!bh) {
			printk(KERN_ERR "EFS: readdir(): failed to read dir block %d\n", block);
			break;
		}
 
		dirblock = (struct efs_dir *) bh->b_data; 
 
		if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
			printk(KERN_ERR "EFS: readdir(): invalid directory block\n");
			brelse(bh);
			break;
		}
 
		while (slot < dirblock->slots) {
			if (dirblock->space[slot] == 0) {
				slot++;
				continue;
			}
 
			dirslot  = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
 
			inodenum = be32_to_cpu(dirslot->inode);
			namelen  = dirslot->namelen;
			nameptr  = dirslot->name;
 
#ifdef DEBUG
			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);
#endif
			if (namelen > 0) {
				/* found the next entry */
				filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
 
				/* copy filename and data in dirslot */
				filldir(dirent, nameptr, namelen, filp->f_pos, inodenum, DT_UNKNOWN);
 
				/* sanity check */
				if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) {
					printk(KERN_WARNING "EFS: directory entry %d exceeds directory block\n", slot);
					slot++;
					continue;
				}
 
				/* store position of next slot */
				if (++slot == dirblock->slots) {
					slot = 0;
					block++;
				}
				brelse(bh);
				filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
				goto out;
			}
			slot++;
		}
		brelse(bh);
 
		slot = 0;
		block++;
	}
 
	filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
out:
	unlock_kernel();
	return 0;
}