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 @@
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",