Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755529Ab2J0IYU (ORCPT ); Sat, 27 Oct 2012 04:24:20 -0400 Received: from li9-11.members.linode.com ([67.18.176.11]:57953 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755173Ab2J0IYQ convert rfc822-to-8bit (ORCPT ); Sat, 27 Oct 2012 04:24:16 -0400 Date: Sat, 27 Oct 2012 04:24:13 -0400 From: "Theodore Ts'o" To: Toralf =?iso-8859-1?Q?F=F6rster?= Cc: Linux Kernel Subject: Re: RFC: kconfig option CONFIG_LBDAF should be auto-selected if EXT4 is chosen Message-ID: <20121027082413.GB12045@thunk.org> Mail-Followup-To: Theodore Ts'o , Toralf =?iso-8859-1?Q?F=F6rster?= , Linux Kernel References: <508A967F.4080802@gmx.de> <508B94AE.9050505@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <508B94AE.9050505@gmx.de> User-Agent: Mutt/1.5.21 (2010-09-15) Content-Transfer-Encoding: 8BIT X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1530 Lines: 37 On Sat, Oct 27, 2012 at 10:00:46AM +0200, Toralf F?rster wrote: > > otherwise booting an EXT4 image won't work b/c the root fs can't be > mounted read-write - and as a side effect no syslog messages might > point the user to this issue (at least in my setup) ... This is only a problem on 32-bit architectues. and it's actually documented in the Kconfig help message, and it's enabled by default. So someone would have had to have gone out of their way to turn off CONFIG_LBDAF. This is the first time I've heard of someone getting surprised by this; do you know how CONFIG_LBDAF got disabled? Did you just disable it without reading the help message? What we might be able to do instead is to allow the mount to succeed, but to simply fail any attempts to open(2) or stat(2) files larger than 2TB with an EFBIG error. BTW, technically ext4 does not _require_ CONFIG_LBDAF. It's just that the default mke2fs.conf enables huge_file, so most ext4 file systems enable it by default. I could imagine systems (like 32-bit Android handsets) where it's not intended to ever support storage devices larger than 2TB, so they might very well wnat CONFIG_EXT4 && !CONFIG_LBDAF. That's a valid choice, although I do admit some users might get surprised by this. Regards, - Ted -- 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/