/*
 * used by Felix to test xfs_fsr filesystem corruption,
 * source originally from http://froebe.net/blog/wp-content/uploads/2007/05/dio.c
 */


#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <string.h>

#define _GNU_SOURCE
#define __USE_GNU
#define __USE_LARGEFILE64


#define BUFFER_SIZE 1048576

#include <fcntl.h>

int main(int argc, char **argv)
{
	int test_fd;
	int input_fd;
	int bytes_read;
	long long bytes_written = 0;
	int i;
	int pagesize = getpagesize();

	char *realbuff = malloc(BUFFER_SIZE + pagesize);
	char *alignedbuff = ((( (int unsigned)realbuff + pagesize - 1) / pagesize) * pagesize);

	input_fd = open("/dev/zero", O_RDONLY);
	test_fd = open("./test.dat", O_CREAT|O_WRONLY|O_DIRECT|O_ASYNC|O_LARGEFILE, 0666);

	if (test_fd < 0) {
		printf("couldn't open test.dat\n");
		exit(1);
	}

	for (i=0; i < 20480; i++) {
		bytes_read = read(input_fd, alignedbuff, BUFFER_SIZE);
		bytes_written += write(test_fd, alignedbuff, bytes_read);

		if (errno == 0) {
			printf("%lu MBytes written\n", (long)(bytes_written / 1048576));
		} else {
			fprintf(stderr, "write failed (err %d): %s\n", errno, strerror(errno));
		}
	}

	return 0;
}