/*
 * test-writehints.c: test file/inode write hint setting/getting
 */
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdbool.h>
#include <inttypes.h>
#include <assert.h>

#ifndef F_GET_RW_HINT
#define F_LINUX_SPECIFIC_BASE	1024
#define F_GET_RW_HINT		(F_LINUX_SPECIFIC_BASE + 11)
#define F_SET_RW_HINT		(F_LINUX_SPECIFIC_BASE + 12)
#define F_GET_FILE_RW_HINT	(F_LINUX_SPECIFIC_BASE + 13)
#define F_SET_FILE_RW_HINT	(F_LINUX_SPECIFIC_BASE + 14)

#define RWH_WRITE_LIFE_NOT_SET	0
#define RWH_WRITE_LIFE_NONE	1
#define RWH_WRITE_LIFE_SHORT	2
#define RWH_WRITE_LIFE_MEDIUM	3
#define RWH_WRITE_LIFE_LONG	4
#define RWH_WRITE_LIFE_EXTREME	5

#endif

static int __get_write_hint(int fd, int cmd)
{
	uint64_t hint;
	int ret;

	ret = fcntl(fd, cmd, &hint);
	if (ret < 0) {
		perror("fcntl: F_GET_RW_FILE_HINT");
		return -1;
	}

	return hint;
}

static int get_file_write_hint(int fd)
{
	return __get_write_hint(fd, F_GET_FILE_RW_HINT);
}

static int get_inode_write_hint(int fd)
{
	return __get_write_hint(fd, F_GET_RW_HINT);
}

static void set_file_write_hint(int fd, uint64_t hint)
{
	uint64_t set_hint = hint;
	int ret;

	ret = fcntl(fd, F_SET_FILE_RW_HINT, &set_hint);
	if (ret < 0) {
		perror("fcntl: F_RW_SET_HINT");
		return;
	}
}

static void set_inode_write_hint(int fd, uint64_t hint)
{
	uint64_t set_hint = hint;
	int ret;

	ret = fcntl(fd, F_SET_RW_HINT, &set_hint);
	if (ret < 0) {
		perror("fcntl: F_RW_SET_HINT");
		return;
	}
}

int main(int argc, char *argv[])
{
	char filename[] = "/tmp/writehintsXXXXXX";
	int ihint, fhint, fd, dupfd;

	fd = mkstemp(filename);
	if (fd < 0) {
		perror("open");
		return 2;
	}

	/*
	 * Default hints for both file and inode should be NOT_SET
	 */
	fhint = get_file_write_hint(fd);
	if (fhint < 0)
		return 0;
	ihint = get_inode_write_hint(fd);
	assert(fhint == ihint);
	assert(fhint == RWH_WRITE_LIFE_NOT_SET);

	/*
	 * Set inode hint, check file hint returns the right hint
	 */
	set_inode_write_hint(fd, RWH_WRITE_LIFE_SHORT);
	fhint = get_file_write_hint(fd);
	ihint = get_inode_write_hint(fd);
	assert(fhint == ihint);
	assert(fhint == RWH_WRITE_LIFE_SHORT);

	/*
	 * Check that a duped descriptor returns the right hint
	 */
	dupfd = dup(fd);
	fhint = get_file_write_hint(dupfd);
	ihint = get_inode_write_hint(dupfd);
	assert(fhint == RWH_WRITE_LIFE_SHORT);
	assert(ihint == RWH_WRITE_LIFE_SHORT);

	/*
	 * Now set file hint, ensure that this is now the hint we get
	 */
	set_file_write_hint(fd, RWH_WRITE_LIFE_LONG);
	fhint = get_file_write_hint(fd);
	ihint = get_inode_write_hint(fd);
	assert(fhint == RWH_WRITE_LIFE_LONG);
	assert(ihint == RWH_WRITE_LIFE_SHORT);

	/*
	 * Clear inode write hint, ensure that file still returns the set hint
	 */
	set_inode_write_hint(fd, RWH_WRITE_LIFE_NOT_SET);
	fhint = get_file_write_hint(fd);
	ihint = get_inode_write_hint(fd);
	assert(fhint == RWH_WRITE_LIFE_LONG);
	assert(ihint == RWH_WRITE_LIFE_NOT_SET);

	/*
	 * Clear file write hint, ensure that now returns cleared
	 */
	set_file_write_hint(fd, RWH_WRITE_LIFE_NOT_SET);
	fhint = get_file_write_hint(fd);
	assert(fhint == RWH_WRITE_LIFE_NOT_SET);

	close(fd);
	close(dupfd);
	unlink(filename);
	return 0;
}