v4.19.13 snapshot.
diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c
new file mode 100644
index 0000000..8c6ab6c
--- /dev/null
+++ b/fs/efivarfs/inode.c
@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
+ *
+ * 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.
+ */
+
+#include <linux/efi.h>
+#include <linux/fs.h>
+#include <linux/ctype.h>
+#include <linux/slab.h>
+#include <linux/uuid.h>
+
+#include "internal.h"
+
+struct inode *efivarfs_get_inode(struct super_block *sb,
+ const struct inode *dir, int mode,
+ dev_t dev, bool is_removable)
+{
+ struct inode *inode = new_inode(sb);
+
+ if (inode) {
+ inode->i_ino = get_next_ino();
+ inode->i_mode = mode;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
+ inode->i_flags = is_removable ? 0 : S_IMMUTABLE;
+ switch (mode & S_IFMT) {
+ case S_IFREG:
+ inode->i_fop = &efivarfs_file_operations;
+ break;
+ case S_IFDIR:
+ inode->i_op = &efivarfs_dir_inode_operations;
+ inode->i_fop = &simple_dir_operations;
+ inc_nlink(inode);
+ break;
+ }
+ }
+ return inode;
+}
+
+/*
+ * Return true if 'str' is a valid efivarfs filename of the form,
+ *
+ * VariableName-12345678-1234-1234-1234-1234567891bc
+ */
+bool efivarfs_valid_name(const char *str, int len)
+{
+ const char *s = str + len - EFI_VARIABLE_GUID_LEN;
+
+ /*
+ * We need a GUID, plus at least one letter for the variable name,
+ * plus the '-' separator
+ */
+ if (len < EFI_VARIABLE_GUID_LEN + 2)
+ return false;
+
+ /* GUID must be preceded by a '-' */
+ if (*(s - 1) != '-')
+ return false;
+
+ /*
+ * Validate that 's' is of the correct format, e.g.
+ *
+ * 12345678-1234-1234-1234-123456789abc
+ */
+ return uuid_is_valid(s);
+}
+
+static int efivarfs_create(struct inode *dir, struct dentry *dentry,
+ umode_t mode, bool excl)
+{
+ struct inode *inode = NULL;
+ struct efivar_entry *var;
+ int namelen, i = 0, err = 0;
+ bool is_removable = false;
+
+ if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
+ return -EINVAL;
+
+ var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
+ if (!var)
+ return -ENOMEM;
+
+ /* length of the variable name itself: remove GUID and separator */
+ namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
+
+ err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid);
+ if (err)
+ goto out;
+
+ if (efivar_variable_is_removable(var->var.VendorGuid,
+ dentry->d_name.name, namelen))
+ is_removable = true;
+
+ inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable);
+ if (!inode) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ for (i = 0; i < namelen; i++)
+ var->var.VariableName[i] = dentry->d_name.name[i];
+
+ var->var.VariableName[i] = '\0';
+
+ inode->i_private = var;
+
+ err = efivar_entry_add(var, &efivarfs_list);
+ if (err)
+ goto out;
+
+ d_instantiate(dentry, inode);
+ dget(dentry);
+out:
+ if (err) {
+ kfree(var);
+ if (inode)
+ iput(inode);
+ }
+ return err;
+}
+
+static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+ struct efivar_entry *var = d_inode(dentry)->i_private;
+
+ if (efivar_entry_delete(var))
+ return -EINVAL;
+
+ drop_nlink(d_inode(dentry));
+ dput(dentry);
+ return 0;
+};
+
+const struct inode_operations efivarfs_dir_inode_operations = {
+ .lookup = simple_lookup,
+ .unlink = efivarfs_unlink,
+ .create = efivarfs_create,
+};