Could you suggest the ways to cleanup the inode, dentry and data cache upon closing the file at kernel space?

Question

1. From kernel space upon referencing a file with filp_open, kernel_read, file_close.
2. When we try to open the file (filp_open) in kernel space, the corresponding inode dentry will be remove or not, after closing (filp_close) of file pointer.

Sample code which present in kernel space.

static int sample_test_fun(struct file *filp, void __user *_uarg, bool all_users)
      {
         struct sample_device_data_buffer buffer = {0};
         struct file *fp;
         loff_t pos = 0;
         int status, i;

         fp = filp_open("/opt/secure/test/secure_dir/data.txt", O_RDONLY|O_CLOEXEC, 0400);
     if (IS_ERR(fp))
     {
          pr_err("failed to open %p %ld\n", fp, PTR_ERR(fp));
           return PTR_ERR(fp);
     }
       printk("%s:%d:: file isize is from inode %lld\n",__FUNCTION__, __LINE__, (file_inode(fp))->i_size);
       buffer.len = file_inode(fp)->i_size;
       printk("%s: file size is %d \n", __FUNCTION__, buffer.len);
       buffer.data = kzalloc(buffer.len, GFP_KERNEL);
       if (!buffer.data)
       {
               printk("%s: allocation failed for size %d \n", __FUNCTION__, buffer.len);
           filp_close(fp, NULL);
           return -ENOMEM;
       }
       printk("%s:%d",__FUNCTION__, __LINE__);
       status = kernel_read(fp, buffer.data, buffer.len, &pos);
       printk("%s:%d read bytes %d",__FUNCTION__, __LINE__, status);
       filp_close(fp, NULL);
       if (status != buffer.len) {
                        if (status >= 0)
                                status = -EIO;
                        goto cleanup;
       }
       for (i=0; i < buffer.len;i++)
       {
               printk(" buffer data %c", buffer.data[i]);
       }
     
   }

We have tried from kernel space upon referencing a file with filp_open, kernel_read, file_close, but after file_close also still the corresponding file inode dentry is not removed.

Please find code logic above.