From 7e99e14d4ba2533a07adc3d97e06cadc41d12908 Mon Sep 17 00:00:00 2001
From: Michael Heimpold <mhei@heimpold.de>
Date: Mon, 20 May 2013 21:34:42 +0200
Subject: tools/fw_env: use fsync to ensure that data is physically stored

Closing a file descriptor does not guarantee that the data has been
successfully saved to disk, as the kernel might defer the write.

Signed-off-by: Michael Heimpold <mhei@heimpold.de>

diff --git a/tools/env/fw_env.c b/tools/env/fw_env.c
index 2861656..c9c79e0 100644
--- a/tools/env/fw_env.c
+++ b/tools/env/fw_env.c
@@ -1088,7 +1088,19 @@ static int flash_io (int mode)
 
 		rc = flash_write (fd_current, fd_target, dev_target);
 
+		if (fsync (fd_current)) {
+			fprintf (stderr,
+				 "fsync failed on %s: %s\n",
+				 DEVNAME (dev_current), strerror (errno));
+		}
+
 		if (HaveRedundEnv) {
+			if (fsync (fd_target)) {
+				fprintf (stderr,
+					 "fsync failed on %s: %s\n",
+					 DEVNAME (dev_current), strerror (errno));
+			}
+
 			if (close (fd_target)) {
 				fprintf (stderr,
 					"I/O error on %s: %s\n",
-- 
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