mcoverlayfs: add new base from 4.18.14

This just lays out new files so the next commit is easier to review;
nothing changes here

Change-Id: I66669877d2d10632f5436c0eeb32248cd4c8b996

executer/kernel/mcoverlayfs/linux-4.18.14/ovl_entry.h

@@ -0,0 +1,111 @@
+/*
+ *
+ * Copyright (C) 2011 Novell Inc.
+ * Copyright (C) 2016 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+struct ovl_config {
+	char *lowerdir;
+	char *upperdir;
+	char *workdir;
+	bool default_permissions;
+	bool redirect_dir;
+	bool redirect_follow;
+	const char *redirect_mode;
+	bool index;
+	bool nfs_export;
+	int xino;
+};
+
+struct ovl_sb {
+	struct super_block *sb;
+	dev_t pseudo_dev;
+};
+
+struct ovl_layer {
+	struct vfsmount *mnt;
+	struct ovl_sb *fs;
+	/* Index of this layer in fs root (upper idx == 0) */
+	int idx;
+	/* One fsid per unique underlying sb (upper fsid == 0) */
+	int fsid;
+};
+
+struct ovl_path {
+	struct ovl_layer *layer;
+	struct dentry *dentry;
+};
+
+/* private information held for overlayfs's superblock */
+struct ovl_fs {
+	struct vfsmount *upper_mnt;
+	unsigned int numlower;
+	/* Number of unique lower sb that differ from upper sb */
+	unsigned int numlowerfs;
+	struct ovl_layer *lower_layers;
+	struct ovl_sb *lower_fs;
+	/* workbasedir is the path at workdir= mount option */
+	struct dentry *workbasedir;
+	/* workdir is the 'work' directory under workbasedir */
+	struct dentry *workdir;
+	/* index directory listing overlay inodes by origin file handle */
+	struct dentry *indexdir;
+	long namelen;
+	/* pathnames of lower and upper dirs, for show_options */
+	struct ovl_config config;
+	/* creds of process who forced instantiation of super block */
+	const struct cred *creator_cred;
+	bool tmpfile;
+	bool noxattr;
+	/* Did we take the inuse lock? */
+	bool upperdir_locked;
+	bool workdir_locked;
+	/* Inode numbers in all layers do not use the high xino_bits */
+	unsigned int xino_bits;
+};
+
+/* private information held for every overlayfs dentry */
+struct ovl_entry {
+	union {
+		struct {
+			unsigned long flags;
+		};
+		struct rcu_head rcu;
+	};
+	unsigned numlower;
+	struct ovl_path lowerstack[];
+};
+
+struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
+
+static inline struct ovl_entry *OVL_E(struct dentry *dentry)
+{
+	return (struct ovl_entry *) dentry->d_fsdata;
+}
+
+struct ovl_inode {
+	struct ovl_dir_cache *cache;
+	const char *redirect;
+	u64 version;
+	unsigned long flags;
+	struct inode vfs_inode;
+	struct dentry *__upperdentry;
+	struct inode *lower;
+
+	/* synchronize copy up and more */
+	struct mutex lock;
+};
+
+static inline struct ovl_inode *OVL_I(struct inode *inode)
+{
+	return container_of(inode, struct ovl_inode, vfs_inode);
+}
+
+static inline struct dentry *ovl_upperdentry_dereference(struct ovl_inode *oi)
+{
+	return READ_ONCE(oi->__upperdentry);
+}