NFSv4: truncate returns I/O error

[Miklos Szeredi <miklos@xxxxxxxxxx>]

The attached test program reliably fails on an NFSv4 mount.

# mount -tnfs -onfsvers=4 127.0.0.1:/ /mnt/nfs
# ./truncate-test /mnt/nfs/tmp/xyz
truncate: Input/output error

Thanks,
Miklos

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>

int main(int argc, char *argv[])
{
	int res;
	char *name = argv[1];

	unlink(name);
	close(open(name, O_WRONLY | O_CREAT, 0644));
	close(open(name, O_RDONLY));

	res = truncate(name, 1);
	if (res == -1) {
		perror("truncate");
		return 1;
	}
    return 0;
}