+static int secretmem_setattr(struct user_namespace *mnt_userns,
+ struct dentry *dentry, struct iattr *iattr)
+{
+ struct inode *inode = d_inode(dentry);
+ struct address_space *mapping = inode->i_mapping;
+ unsigned int ia_valid = iattr->ia_valid;
+ int ret;
+
+ filemap_invalidate_lock(mapping);
+
+ if ((ia_valid & ATTR_SIZE) && inode->i_size)
+ ret = -EINVAL;
+ else
+ ret = simple_setattr(mnt_userns, dentry, iattr);
+
+ filemap_invalidate_unlock(mapping);
+
+ return ret;
+}
+
+static const struct inode_operations secretmem_iops = {
+ .setattr = secretmem_setattr,
+};
+