dir.c

课程设计

#include <linux/fs.h>
#include <linux/buffer_head.h>

#include "xbfs.h"


int dir_sanity_check(ino_t ino, struct xbfs_inode_disk *id)
{
	if (!S_ISDIR(id->mode)) {
		DPRINT("inode %ld is fucked. mode is not dir\n", ino);
		return 1;
	}
	return 0;
}

static int xbfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
	struct inode *inode;
	struct xbfs_inode_disk *id;
	struct buffer_head *bh;
	struct xbfs_dirent *ent;
	unsigned long pos = filp->f_pos;
	unsigned long i;
	int err;

	DPRINT("pos %ld\n", pos);

	inode = filp->f_dentry->d_inode;
	bh = sb_bread(inode->i_sb, inode->i_ino);
	if (!bh) {
		DPRINT("sb_bread inode %ld error\n", inode->i_ino);
		return -EINVAL;
	}
	
	err = -EINVAL;
	id = (typeof(id))bh->b_data;
	if (dir_sanity_check(inode->i_ino, id))
		goto out_relse;

	i = pos;
	pos = 0;
	for_each_dirent(id, ent, {
		int len;
		
		if (pos < i)
			continue;

		len = strnlen(ent->name, sizeof(ent->name) - 1);
		ent->name[len] = 0;

		DPRINT("filldir name %s ino %d\n", ent->name, ent->block);

		err = filldir(dirent, ent->name, len, pos, ent->block, DT_UNKNOWN);
		if (err)
			goto done;
		pos++;
	});

	err = 0;

done:
	filp->f_pos = pos;

out_relse:
	brelse(bh);
	return err;
}

const struct file_operations xbfs_dir_operations = {
	.read		= generic_read_dir,
	.readdir	= xbfs_readdir
};