/*
 * dir.c
 *
 * Copyright (c) 1999 Al Smith
 *
 * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
 */

#include <linux/efs.h>

static int efs_readdir(struct file *, void *, filldir_t);

static struct file_operations efs_dir_operations = {
	NULL,		/* lseek */
	NULL,		/* read */
	NULL,		/* write */
	efs_readdir,
	NULL,		/* poll */
	NULL,		/* ioctl */
	NULL,		/* no special open code */
	NULL,		/* flush */
	NULL,		/* no special release code */
	NULL		/* fsync */
};

struct inode_operations efs_dir_inode_operations = {
	&efs_dir_operations,
	NULL,		/* create */
	efs_lookup,
	NULL,		/* link */
	NULL,		/* unlink */
	NULL,		/* symlink */
	NULL,		/* mkdir */
	NULL,		/* rmdir */
	NULL,		/* mknod */
	NULL,		/* rename */
	NULL,		/* readlink */
	NULL,		/* follow_link */
	NULL,		/* readpage */
	NULL,		/* writepage */
	efs_bmap,
	NULL,		/* truncate */
	NULL		/* permission */
};

/* read the next entry for a given directory */

static int efs_readdir(struct file *filp, void *dirent, filldir_t filldir) {
	struct inode *inode = filp->f_dentry->d_inode;
	struct efs_in_info *ini = (struct efs_in_info *) &inode->u.generic_ip;
	struct buffer_head *bh;

	struct efs_dir		*dirblock;
	struct efs_dentry	*dirslot;
	efs_ino_t		inodenum;
	efs_block_t		block;
	int			slot, namelen, numslots;
	char			*nameptr;

	if (!inode || !S_ISDIR(inode->i_mode)) 
		return -EBADF;
  
	if (ini->numextents != 1)
		printk("EFS: WARNING: readdir(): more than one extent\n");

	if (inode->i_size & (EFS_BLOCKSIZE-1))
		printk("EFS: WARNING: readdir(): directory size not a multiple of EFS_BLOCKSIZE\n");

	/* work out the block where this entry can be found */
	block = filp->f_pos >> EFS_BLOCKSIZE_BITS;
  
	/* don't read past last entry */
	if (block > inode->i_blocks) return 0;

	/* read the dir block */
	bh = bread(inode->i_dev, efs_bmap(inode, block), EFS_BLOCKSIZE);

	if (!bh) {
		printk("EFS: readdir(): failed to read dir block %d\n", block);
		return 0;
	}

	dirblock = (struct efs_dir *) bh->b_data; 

	if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
		printk("EFS: readdir(): invalid directory block\n");
		brelse(bh);
		return(0);
	}

	slot     = filp->f_pos & 0xff;

	dirslot  = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));

	numslots = dirblock->slots;
        inodenum = be32_to_cpu(dirslot->inode);
	namelen  = dirslot->namelen;
	nameptr  = dirslot->name;

#ifdef DEBUG
	printk("EFS: dent #%d: inode %u, name \"%s\", namelen %u\n", slot, inodenum, nameptr, namelen);
#endif

	/* copy filename and data in dirslot */
	filldir(dirent, nameptr, namelen, filp->f_pos, inodenum);

	brelse(bh);

	/* store position of next slot */
	if (++slot == numslots) {
		slot = 0;
		block++;
	}

	filp->f_pos = (block << EFS_BLOCKSIZE_BITS) | slot;
  
	return 0;
}