Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965586Ab3HHOq7 (ORCPT ); Thu, 8 Aug 2013 10:46:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20709 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965524Ab3HHOq4 (ORCPT ); Thu, 8 Aug 2013 10:46:56 -0400 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <20130801173846.28023.19009.stgit@warthog.procyon.org.uk> <20130801173854.28023.82045.stgit@warthog.procyon.org.uk> To: Nico Williams Cc: dhowells@redhat.com, keyrings@linux-nfs.org, linux-nfs@vger.kernel.org, simo@redhat.com, linux-kernel@vger.kernel.org, krbdev@mit.edu Subject: Re: [PATCH 1/2] KEYS: Implement a big key type that can save to tmpfs Date: Thu, 08 Aug 2013 15:46:45 +0100 Message-ID: <16961.1375973205@warthog.procyon.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1122 Lines: 26 Nico Williams wrote: > b) how to create tmpfs locations in which to store credentials (which > can be unbounded in size, so storing them in the kernel is silly; Ummm... tmpfs stores them in the kernel too - though it can page them out to swap. I have altered my big-key implementation to just store small items in an internal buffer and big items in a tmpfs file. This means that small items will use up _less_ kernel memory if they're in a key because they won't require the overhead of a dentry struct and an inode struct. > (b) can be solved in many ways, and the simplest is to have a > filesystem where top-level directories named after UIDs "exist" as > soon as they are referenced and as long as they are non-empty. You > can use autofs + tmpfs, or a variant of tmpfs for this. Don't forget to add user namespaces into the mix :-/ David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/