v4.19.13 snapshot.
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
new file mode 100644
index 0000000..540595a
--- /dev/null
+++ b/include/linux/posix_acl.h
@@ -0,0 +1,124 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+  File: linux/posix_acl.h
+
+  (C) 2002 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+*/
+
+
+#ifndef __LINUX_POSIX_ACL_H
+#define __LINUX_POSIX_ACL_H
+
+#include <linux/bug.h>
+#include <linux/slab.h>
+#include <linux/rcupdate.h>
+#include <linux/refcount.h>
+#include <uapi/linux/posix_acl.h>
+
+struct posix_acl_entry {
+	short			e_tag;
+	unsigned short		e_perm;
+	union {
+		kuid_t		e_uid;
+		kgid_t		e_gid;
+	};
+};
+
+struct posix_acl {
+	refcount_t		a_refcount;
+	struct rcu_head		a_rcu;
+	unsigned int		a_count;
+	struct posix_acl_entry	a_entries[0];
+};
+
+#define FOREACH_ACL_ENTRY(pa, acl, pe) \
+	for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)
+
+
+/*
+ * Duplicate an ACL handle.
+ */
+static inline struct posix_acl *
+posix_acl_dup(struct posix_acl *acl)
+{
+	if (acl)
+		refcount_inc(&acl->a_refcount);
+	return acl;
+}
+
+/*
+ * Free an ACL handle.
+ */
+static inline void
+posix_acl_release(struct posix_acl *acl)
+{
+	if (acl && refcount_dec_and_test(&acl->a_refcount))
+		kfree_rcu(acl, a_rcu);
+}
+
+
+/* posix_acl.c */
+
+extern void posix_acl_init(struct posix_acl *, int);
+extern struct posix_acl *posix_acl_alloc(int, gfp_t);
+extern int posix_acl_valid(struct user_namespace *, const struct posix_acl *);
+extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
+extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
+extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
+extern int __posix_acl_create(struct posix_acl **, gfp_t, umode_t *);
+extern int __posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);
+
+extern struct posix_acl *get_posix_acl(struct inode *, int);
+extern int set_posix_acl(struct inode *, int, struct posix_acl *);
+
+#ifdef CONFIG_FS_POSIX_ACL
+extern int posix_acl_chmod(struct inode *, umode_t);
+extern int posix_acl_create(struct inode *, umode_t *, struct posix_acl **,
+		struct posix_acl **);
+extern int posix_acl_update_mode(struct inode *, umode_t *, struct posix_acl **);
+
+extern int simple_set_acl(struct inode *, struct posix_acl *, int);
+extern int simple_acl_create(struct inode *, struct inode *);
+
+struct posix_acl *get_cached_acl(struct inode *inode, int type);
+struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type);
+void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl);
+void forget_cached_acl(struct inode *inode, int type);
+void forget_all_cached_acls(struct inode *inode);
+
+static inline void cache_no_acl(struct inode *inode)
+{
+	inode->i_acl = NULL;
+	inode->i_default_acl = NULL;
+}
+#else
+static inline int posix_acl_chmod(struct inode *inode, umode_t mode)
+{
+	return 0;
+}
+
+#define simple_set_acl		NULL
+
+static inline int simple_acl_create(struct inode *dir, struct inode *inode)
+{
+	return 0;
+}
+static inline void cache_no_acl(struct inode *inode)
+{
+}
+
+static inline int posix_acl_create(struct inode *inode, umode_t *mode,
+		struct posix_acl **default_acl, struct posix_acl **acl)
+{
+	*default_acl = *acl = NULL;
+	return 0;
+}
+
+static inline void forget_all_cached_acls(struct inode *inode)
+{
+}
+#endif /* CONFIG_FS_POSIX_ACL */
+
+struct posix_acl *get_acl(struct inode *inode, int type);
+
+#endif  /* __LINUX_POSIX_ACL_H */