From 77d506d5de4e9fa052b68857753b9f9520a33cf3 Mon Sep 17 00:00:00 2001
From: Jiang Liu <gerry@linux.alibaba.com>
Date: Tue, 14 Nov 2023 16:49:32 +0800
Subject: [PATCH] ptfs: refine the way to support O_DIRECT

We have special support of the O_DIRECT flag, but the implementation
has race conditions due to `Time To Check & Time To Use` issues.
So refine the implementation by using a RwLock.

Signed-off-by: Jiang Liu <gerry@linux.alibaba.com>