From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Tso Subject: Re: [RFC 0/13] extents and 48bit ext3 Date: Fri, 9 Jun 2006 18:04:41 -0400 Message-ID: <20060609220441.GH10524@thunk.org> References: <4489D36C.3010000@garzik.org> <20060609203523.GE10524@thunk.org> <4489EAFE.6090303@garzik.org> <87ac8matr2.fsf@graviton.dyn.troilus.org> <4489EDCA.5040808@garzik.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Andrew Morton , ext2-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Michael Poole , Christoph Hellwig , Gerrit Huizenga , cmm@us.ibm.com, linux-fsdevel@vger.kernel.org Return-path: To: Jeff Garzik Content-Disposition: inline In-Reply-To: <4489EDCA.5040808@garzik.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: ext2-devel-bounces@lists.sourceforge.net Errors-To: ext2-devel-bounces@lists.sourceforge.net List-Id: linux-fsdevel.vger.kernel.org On Fri, Jun 09, 2006 at 05:53:14PM -0400, Jeff Garzik wrote: > Yes, it's not a small change to the on-disk format. > > If you write tools that read an ext3 filesystem, you won't be able to > read file data at all, without updating your code. Most tools that read an ext2/3 filesystem directly use the libext2fs library, and it will definitely be the case that for files smaller than 4TB, even on a filesystem with extents enabled, as long as you are using a version of libext2fs which is extents-aware, it will work without any changes. For files larger than 4TB, we will need some kind of LFS-like interface change (i.e., ext2fs_file_llseek64 vs. ext2fs_file_llseek), but that should be the only change needed by the tool. - Ted