--- /dev/null
+From 2d5b86e048780c5efa7f7d9708815555919e7b05 Mon Sep 17 00:00:00 2001
+From: Eric Sandeen <sandeen@redhat.com>
+Date: Thu, 12 Feb 2015 23:07:37 -0500
+Subject: ext4: ignore journal checksum on remount; don't fail
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: Eric Sandeen <sandeen@redhat.com>
+
+commit 2d5b86e048780c5efa7f7d9708815555919e7b05 upstream.
+
+As of v3.18, ext4 started rejecting a remount which changes the
+journal_checksum option.
+
+Prior to that, it was simply ignored; the problem here is that
+if someone has this in their fstab for the root fs, now the box
+fails to boot properly, because remount of root with the new options
+will fail, and the box proceeds with a readonly root.
+
+I think it is a little nicer behavior to accept the option, but
+warn that it's being ignored, rather than failing the mount,
+but that might be a subjective matter...
+
+Reported-by: Cónräd <conradsand.arma@gmail.com>
+Signed-off-by: Eric Sandeen <sandeen@redhat.com>
+Signed-off-by: Theodore Ts'o <tytso@mit.edu>
+Cc: Josh Boyer <jwboyer@fedoraproject.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/ext4/super.c | 5 ++---
+ 1 file changed, 2 insertions(+), 3 deletions(-)
+
+--- a/fs/ext4/super.c
++++ b/fs/ext4/super.c
+@@ -4864,9 +4864,8 @@ static int ext4_remount(struct super_blo
+ if ((old_opts.s_mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) ^
+ test_opt(sb, JOURNAL_CHECKSUM)) {
+ ext4_msg(sb, KERN_ERR, "changing journal_checksum "
+- "during remount not supported");
+- err = -EINVAL;
+- goto restore_opts;
++ "during remount not supported; ignoring");
++ sbi->s_mount_opt ^= EXT4_MOUNT_JOURNAL_CHECKSUM;
+ }
+
+ if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {