dir.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

/*
 *  linux/fs/minix/dir.c
 *
 *  Copyright (C) 1991, 1992 Linus Torvalds
 *
 *  minix directory handling functions
 */

#include <linux/string.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/minix_fs.h>
#include <linux/stat.h>

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

struct file_operations minix_dir_operations = {
	read:		generic_read_dir,
	readdir:	minix_readdir,
	fsync:		file_fsync,
};

static int minix_readdir(struct file * filp,
	void * dirent, filldir_t filldir)
{
	unsigned int offset;
	struct buffer_head * bh;
	struct minix_dir_entry * de;
	struct minix_sb_info * info;
	struct inode *inode = filp->f_dentry->d_inode;

	info = &inode->i_sb->u.minix_sb;
	if (filp->f_pos & (info->s_dirsize - 1))
		return -EBADF;
	while (filp->f_pos < inode->i_size) {
		offset = filp->f_pos & 1023;
		bh = minix_bread(inode,(filp->f_pos)>>BLOCK_SIZE_BITS,0);
		if (!bh) {
			filp->f_pos += 1024-offset;
			continue;
		}
		do {
			de = (struct minix_dir_entry *) (offset + bh->b_data);
			if (de->inode) {
				int size = strnlen(de->name, info->s_namelen);
				if (filldir(dirent, de->name, size, filp->f_pos, de->inode, DT_UNKNOWN) < 0) {
					brelse(bh);
					return 0;
				}
			}
			offset += info->s_dirsize;
			filp->f_pos += info->s_dirsize;
		} while (offset < 1024 && filp->f_pos < inode->i_size);
		brelse(bh);
	}
	UPDATE_ATIME(inode);
	return 0;
}