From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jim Cromie Subject: Re: Upgrading datastructures between different filesystem versions Date: Tue, 25 Sep 2007 23:40:59 -0600 Message-ID: <46F9F0EB.6020404@gmail.com> References: <7e77a4050709250827p26683c6bqc65832783ba1c365@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, kernelnewbies@nl.linux.org To: kernel learner Return-path: Received: from wa-out-1112.google.com ([209.85.146.178]:29269 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752776AbXIZFso (ORCPT ); Wed, 26 Sep 2007 01:48:44 -0400 Received: by wa-out-1112.google.com with SMTP id v27so2666499wah for ; Tue, 25 Sep 2007 22:48:44 -0700 (PDT) In-Reply-To: <7e77a4050709250827p26683c6bqc65832783ba1c365@mail.gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org kernel learner wrote: > Hi, > > ext3 filesystem has 32-bit block address and ext4 filesystem has > 48-bit block address. If a user installs ext4, how will the file > system handle already existing block with 32 bit values? Why should it ? thats what ext3 is for. your kernel can have both FS's supported, and would use ext3 drivers for ext3 filesystems its asked to mount. Id expect ext4 drivers handling ext3 filesystems is a distant, secondary goal to getting a fast, reliable, clean 48bit filesystem working. > Can anyone point me to the correct pointer for this backward > compatibility stuff? I searched for it but cudn't find much info. Is > the work still pending on this front? > > Thanks, > KL