From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965309Ab3GSAA4 (ORCPT ); Thu, 18 Jul 2013 20:00:56 -0400 Received: from terminus.zytor.com ([198.137.202.10]:60317 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759224Ab3GSAAy (ORCPT ); Thu, 18 Jul 2013 20:00:54 -0400 Message-ID: <51E88176.6040505@zytor.com> Date: Thu, 18 Jul 2013 16:59:50 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Andrew Morton CC: Rob Landley , linux-kernel@vger.kernel.org, Alexander Viro , "Eric W. Biederman" , Greg Kroah-Hartman , Hugh Dickins , Jeff Layton , Jens Axboe , Jim Cromie , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Rusty Russell , Sam Ravnborg , Stephen Warren Subject: Re: [PATCH 0/5] initmpfs v2: use tmpfs instead of ramfs for rootfs References: <20130715140135.0f896a584fec9f7861049b64@linux-foundation.org> <20130717160602.4b225ac80b1cb6121cbb489c@linux-foundation.org> In-Reply-To: <20130717160602.4b225ac80b1cb6121cbb489c@linux-foundation.org> X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/17/2013 04:06 PM, Andrew Morton wrote: > On Tue, 16 Jul 2013 08:31:13 -0700 (PDT) Rob Landley wrote: > >> Use tmpfs for rootfs when CONFIG_TMPFS=y and there's no root=. >> Specify rootfstype=ramfs to get the old initramfs behavior. >> >> The previous initramfs code provided a fairly crappy root filesystem: >> didn't let you --bind mount directories out of it, reported zero >> size/usage so it didn't show up in "df" and couldn't run things like >> rpm that query available space before proceeding, would fill up all >> available memory and panic the system if you wrote too much to it... > > The df problem and the mount --bind thing are ramfs issues, are they > not? Can we fix them? If so, that's a less intrusive change, and we > also get a fixed ramfs. > mount --bind might be useful to fix for ramfs in general (as ramfs should provide minimal standard filesystem functionality, and that one counts, I believe), but honestly... we should have had tmpfs as a root filesystem option either as rootfs or as an automatic overmount a long time ago. The automatic overmount option (that is tmpfs on top of rootfs) is nice in some ways, as it makes garbage-collecting the inittmpfs trivial; this might save some boot time in the more conventional root scenarios. On the other hand, it doesn't exactly seem to be a big problem to just unlink everything. -hpa