From: Miklos Szeredi <mszeredi@redhat.com>
Date: Mon, 31 Oct 2016 13:42:14 +0000 (+0100)
Subject: ovl: fsync after copy-up
X-Git-Tag: firefly_0821_release~176^2~4^2~19^2~34
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e3d312c435dd98a8b7a8dbaca9568f20449d5e47;p=firefly-linux-kernel-4.4.55.git

ovl: fsync after copy-up

commit 641089c1549d8d3df0b047b5de7e9a111362cdce upstream.

Make sure the copied up file hits the disk before renaming to the final
destination.  If this is not done then the copy-up may corrupt the data in
the file in case of a crash.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index ea0dd9ee138d..63a0d0ba36de 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -139,6 +139,8 @@ static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
 		len -= bytes;
 	}
 
+	if (!error)
+		error = vfs_fsync(new_file, 0);
 	fput(new_file);
 out_fput:
 	fput(old_file);