f2fs: clean up f2fs_ioc_write_checkpoint

Use f2fs_sync_fs to clean up codes in f2fs_ioc_write_checkpoint.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
[Jaegeuk Kim: remove unused err variable]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/file.c

@@ -1619,8 +1619,6 @@ static int f2fs_ioc_write_checkpoint(struct file *filp, unsigned long arg)
 {
 	struct inode *inode = file_inode(filp);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-	struct cp_control cpc;
-	int err;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
@@ -1628,13 +1626,7 @@ static int f2fs_ioc_write_checkpoint(struct file *filp, unsigned long arg)
 	if (f2fs_readonly(sbi->sb))
 		return -EROFS;
 
-	cpc.reason = __get_cp_reason(sbi);
-
-	mutex_lock(&sbi->gc_mutex);
-	err = write_checkpoint(sbi, &cpc);
-	mutex_unlock(&sbi->gc_mutex);
-
-	return err;
+	return f2fs_sync_fs(sbi->sb, 1);
 }
 
 static int f2fs_defragment_range(struct f2fs_sb_info *sbi,