From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.nokia.com ([192.100.105.134] helo=mgw-mx09.nokia.com) by bombadil.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1LmjCu-0003QX-U6 for linux-mtd@lists.infradead.org; Thu, 26 Mar 2009 06:37:00 +0000 Subject: Re: ubifs version 1 compatibility From: Artem Bityutskiy To: Hamish Moffatt In-Reply-To: <20090326051508.GA4760@cloud.net.au> References: <20090326051508.GA4760@cloud.net.au> Content-Type: text/plain; charset="UTF-8" Date: Thu, 26 Mar 2009 08:34:57 +0200 Message-Id: <1238049297.3321.20.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: linux-mtd@lists.infradead.org Reply-To: dedekind@infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2009-03-26 at 16:15 +1100, Hamish Moffatt wrote: > Hi Artem and all, > > I'm upgrading my embedded system which uses UBIFS from 2.6.24 (with a > slightly updated ubifs) to 2.6.29. > > I notice that the new kernel won't read my existing file systems as it > says they are too old - version 1. The code checks for version 3 or 4 I > see. > > My application firmware is generated with mkfs.ubifs and programmed via > ubiupdatevol, but the boot loader on my devices is based on the older > kernel and won't be able to read it. And I have read-write file systems > that will be formatted with the old version too. > > > Is there any solution? I've took a brief look. UBIFS went into mainline with format version 4, and versions 1,2,3 were more development versions. There were changes in the truncation node format and in inode node format. I would probably be possible to have compatibility mode, but it is big job :-( Your boot-loader is Linux kernel-based, right? Does it have write support, or it is read-only? Is it possible to upgrade the boot-loader at the same time you upgrade the kernel on your devices? Side note: now when u-boot supports UBIFS, we need to re-think our versioning scheme and strictly preserve R/O compatibility. -- Best regards, Artem Bityutskiy (Битюцкий Артём)