From f8047f4736cd4c93e6557aa9169320b24333c2f2 Mon Sep 17 00:00:00 2001
From: Joe Thornber <joe@fib011235813.fsnet.co.uk>
Date: Mon, 8 Apr 2002 18:59:50 +0000
Subject: [PATCH] o  Perform a BLKFLSBUF ioctl whenever a block device is
 closed.

Patrick, can you see if this fixes your cluster syncing problem please ?
If so I'll make it so it only syncs if you have actually written to the
device.
---
 lib/device/dev-io.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lib/device/dev-io.c b/lib/device/dev-io.c
index 6f49165ff..30447d3d6 100644
--- a/lib/device/dev-io.c
+++ b/lib/device/dev-io.c
@@ -96,6 +96,12 @@ int dev_open(struct device *dev, int flags)
 	return 1;
 }
 
+static void _flush(int fd)
+{
+	if (ioctl(fd, BLKFLSBUF, 0))
+		log_error("couldn't flush device.");
+}
+
 int dev_close(struct device *dev)
 {
 	if (dev->fd < 0) {
@@ -104,6 +110,8 @@ int dev_close(struct device *dev)
 		return 0;
 	}
 
+	_flush(dev->fd);
+
 	if (close(dev->fd))
 		log_sys_error("close", dev_name(dev));