From owner-freebsd-questions@FreeBSD.ORG Fri Sep 24 20:20:23 2010 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8FEB6106566B for ; Fri, 24 Sep 2010 20:20:23 +0000 (UTC) (envelope-from erikt@midgard.homeip.net) Received: from ch-smtp02.sth.basefarm.net (ch-smtp02.sth.basefarm.net [80.76.149.213]) by mx1.freebsd.org (Postfix) with ESMTP id 1EAA58FC12 for ; Fri, 24 Sep 2010 20:20:23 +0000 (UTC) Received: from c83-255-61-120.bredband.comhem.se ([83.255.61.120]:56234 helo=falcon.midgard.homeip.net) by ch-smtp02.sth.basefarm.net with esmtp (Exim 4.68) (envelope-from ) id 1OzEkF-0006sB-9F for freebsd-questions@freebsd.org; Fri, 24 Sep 2010 22:19:49 +0200 Received: (qmail 25129 invoked from network); 24 Sep 2010 22:19:44 +0200 Received: from owl.midgard.homeip.net (10.1.5.7) by falcon.midgard.homeip.net with ESMTP; 24 Sep 2010 22:19:44 +0200 Received: (qmail 8424 invoked by uid 1001); 24 Sep 2010 22:19:44 +0200 Date: Fri, 24 Sep 2010 22:19:44 +0200 From: Erik Trulsson To: Frank Shute Message-ID: <20100924201944.GA8385@owl.midgard.homeip.net> References: <20100924194800.GA18130@orange.esperance-linux.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100924194800.GA18130@orange.esperance-linux.co.uk> User-Agent: Mutt/1.5.20 (2009-06-14) X-Originating-IP: 83.255.61.120 X-Scan-Result: No virus found in message 1OzEkF-0006sB-9F. X-Scan-Signature: ch-smtp02.sth.basefarm.net 1OzEkF-0006sB-9F c9f9530bbae8ce5dc7a5087f2bfbd36d Cc: Leif Walsh , freebsd-questions@freebsd.org Subject: Re: Linux filesystems accessible from FreeBSD 8-stable? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Sep 2010 20:20:23 -0000 On Fri, Sep 24, 2010 at 08:48:00PM +0100, Frank Shute wrote: > On Thu, Sep 23, 2010 at 01:59:40PM -0400, Leif Walsh wrote: > > > > I can't seem to get a definitive answer on this from the internet, > > there's a lot of conflicting information. > > > > I have some data drives formatted with ext4, which I'd like to access > > from freebsd, preferably without totally reformatting because I don't > > have much temp space for copying. Read-only would be fine, read-write > > would be much preferred. > > > > Is this possible? Am I missing the big "ext4 drivers in > > freebsd/fuse/something" sign? Does anyone happen to know if it's > > possible to migrate an ext4 drive back to ext3, which it seems I can > > access from bsd if I let it pretend the journal doesn't exist? > > > > Wikipedia seems to think you're right in thinking you can migrate (or > mount only?) an ext4 as ext3: > > http://en.wikipedia.org/wiki/Ext4 Well, not quite. That article says: The ext3 file system is partially forward compatible with ext4, that is, an ext4 filesystem can be mounted as an ext3 partition (using "ext3" as the filesystem type when mounting). However, if the ext4 partition uses extents (a major new feature of ext4), then the ability to mount the file system as ext3 is lost. So, if an ext4 filesystem can be mounted as ext3 (and presumably as ext2 since ext3 filesystems can be mounted as ext2) seems to depend on how the ext4 filesystem was created/used. -- Erik Trulsson ertr1013@student.uu.se