--- /dev/null
+From 9f99e50d460ac7fd5f6c9b97aad0088c28c8656d Mon Sep 17 00:00:00 2001
+From: Amir Goldstein <amir73il@gmail.com>
+Date: Wed, 11 Apr 2018 20:09:29 +0300
+Subject: ovl: set lower layer st_dev only if setting lower st_ino
+
+From: Amir Goldstein <amir73il@gmail.com>
+
+commit 9f99e50d460ac7fd5f6c9b97aad0088c28c8656d upstream.
+
+For broken hardlinks, we do not return lower st_ino, so we should
+also not return lower pseudo st_dev.
+
+Fixes: a0c5ad307ac0 ("ovl: relax same fs constraint for constant st_ino")
+Cc: <stable@vger.kernel.org> #v4.15
+Signed-off-by: Amir Goldstein <amir73il@gmail.com>
+Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
+Signed-off-by: Amir Goldstein <amir73il@gmail.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/overlayfs/inode.c | 7 ++-----
+ 1 file changed, 2 insertions(+), 5 deletions(-)
+
+--- a/fs/overlayfs/inode.c
++++ b/fs/overlayfs/inode.c
+@@ -110,13 +110,10 @@ int ovl_getattr(const struct path *path,
+ * that the upper hardlink is not broken.
+ */
+ if (is_dir || lowerstat.nlink == 1 ||
+- ovl_test_flag(OVL_INDEX, d_inode(dentry)))
++ ovl_test_flag(OVL_INDEX, d_inode(dentry))) {
+ stat->ino = lowerstat.ino;
+-
+- if (samefs)
+- WARN_ON_ONCE(stat->dev != lowerstat.dev);
+- else
+ stat->dev = ovl_get_pseudo_dev(dentry);
++ }
+ }
+ if (samefs) {
+ /*