/* DF-3092: single 3584-byte append to BIG.TXT (7 clusters wanted,
 * only 6 real ones remain).  One write(2) so msdosfs_write computes
 * count = 7 and calls extendfile(7) -> clusteralloc(start=40, count=7).
 */
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>

int
main(int argc, char **argv)
{
	char buf[3584];
	ssize_t n;
	int fd;

	if (argc != 2) { fprintf(stderr, "usage: %s file\n", argv[0]); return 1; }
	fd = open(argv[1], O_WRONLY | O_APPEND);
	if (fd < 0) { perror("open"); return 1; }
	memset(buf, 'Z', sizeof(buf));
	n = write(fd, buf, sizeof(buf));
	printf("write(3584) returned %zd", n);
	if (n < 0)
		printf(" errno=%d (%s)", errno, strerror(errno));
	printf("\n");
	if (n >= 3073) {  /* 6 real clusters = 3072 bytes max */
		printf("UNEXPECTED: more than 6 clusters' worth accepted\n");
	}
	return 0;
}