/*
% make CFLAGS='-Wall -Wextra -O3' /tmp/eio
% sudo lvcreate -L 9M -n tst data

echo '
0 1 linear /dev/data/tst 0
1 1 error 1
2 99 linear /dev/data/tst 2' |sudo dmsetup create eio

*/

#include <unistd.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <stdlib.h>
#include <stdio.h>

int main()
{
	char buf[8<<10];
	int fd;

	if (-1==(fd=open("/dev/mapper/eio", O_CREAT|O_RDWR, 00600))) {
	//if (-1==(fd=open("/mnt/t", O_CREAT|O_RDWR, 00600))) {
		perror("open");
		exit(1);
	}

	while (1) {
		// if (sizeof(buf)!=(write(fd, buf, sizeof(buf)))) {
		if (-1==write(fd, buf, sizeof(buf))) {
			perror("write(1)");
			break;
		}
		// break;
	}

	if (0!=fsync(fd))
		perror("fsync(1)");

	if (0!=close(fd))
		perror("close(1)");

	if (-1==(fd=open("/dev/mapper/eio", O_CREAT|O_RDWR, 00600))) {
	//if (-1==(fd=open("/mnt/t", O_CREAT|O_RDWR, 00600))) {
		perror("open");
		exit(1);
	}

	if (0!=fsync(fd))
		perror("fsync(2)");

	if (1!=write(fd, buf, 1))
		perror("write(2)");

	if (0!=fsync(fd))
		perror("fsync(3)");

	return 0;
}