From 9db8d115d940d11747505f9ead8d75b107488680 Mon Sep 17 00:00:00 2001
From: Dominique Martinet <dominique.martinet@cea.fr>
Date: Mon, 19 Nov 2018 17:31:13 +0900
Subject: [PATCH] overlayfs: rhel8 compat for the 4.18 version

rhel8 is a 4.18 kernel but they've already backported some later fixes.
Instead of relying on the kernel version, the changes removed some defines so
we can check for the define presence to make the code more robust to kernel
version wilderness instead

Change-Id: I6cf5548a7b73a7394405daf850f715a1e20ab0b4
---
 .../kernel/mcoverlayfs/linux-4.18.14/super.c  | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/executer/kernel/mcoverlayfs/linux-4.18.14/super.c b/executer/kernel/mcoverlayfs/linux-4.18.14/super.c
index 0aef1670..f9a5a0bc 100644
--- a/executer/kernel/mcoverlayfs/linux-4.18.14/super.c
+++ b/executer/kernel/mcoverlayfs/linux-4.18.14/super.c
@@ -75,6 +75,7 @@ static void ovl_dentry_release(struct dentry *dentry)
 	}
 }
 
+#ifdef D_REAL_UPPER
 static int ovl_check_append_only(struct inode *inode, int flag)
 {
 	/*
@@ -90,16 +91,23 @@ static int ovl_check_append_only(struct inode *inode, int flag)
 
 	return 0;
 }
+#endif
 
 static struct dentry *ovl_d_real(struct dentry *dentry,
+#ifdef D_REAL_UPPER
 				 const struct inode *inode,
 				 unsigned int open_flags, unsigned int flags)
+#else
+				 const struct inode *inode)
+#endif
 {
 	struct dentry *real;
+#ifdef D_REAL_UPPER
 	int err;
 
 	if (flags & D_REAL_UPPER)
 		return ovl_dentry_upper(dentry);
+#endif
 
 	if (!d_is_reg(dentry)) {
 		if (!inode || inode == d_inode(dentry))
@@ -107,19 +115,23 @@ static struct dentry *ovl_d_real(struct dentry *dentry,
 		goto bug;
 	}
 
+#ifdef D_REAL_UPPER
 	if (open_flags) {
 		err = ovl_open_maybe_copy_up(dentry, open_flags);
 		if (err)
 			return ERR_PTR(err);
 	}
+#endif
 
 	real = ovl_dentry_upper(dentry);
 	if (real && (!inode || inode == d_inode(real))) {
+#ifdef D_REAL_UPPER
 		if (!inode) {
 			err = ovl_check_append_only(d_inode(real), open_flags);
 			if (err)
 				return ERR_PTR(err);
 		}
+#endif
 		return real;
 	}
 
@@ -128,7 +140,11 @@ static struct dentry *ovl_d_real(struct dentry *dentry,
 		goto bug;
 
 	/* Handle recursion */
+#ifdef D_REAL_UPPER
 	real = d_real(real, inode, open_flags, 0);
+#else
+	real = d_real(real, inode);
+#endif
 
 	if (!inode || inode == d_inode(real))
 		return real;
@@ -1467,7 +1483,11 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_op = &ovl_super_operations;
 	sb->s_xattr = ovl_xattr_handlers;
 	sb->s_fs_info = ofs;
+#ifdef SB_NOREMOTELOCK
 	sb->s_flags |= SB_POSIXACL | SB_NOREMOTELOCK;
+#else
+	sb->s_flags |= SB_POSIXACL;
+#endif
 
 	err = -ENOMEM;
 	root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, 0));