From: Zheng Liu Subject: Re: hole punching in ext4 Date: Wed, 23 Jan 2013 00:20:09 +0800 Message-ID: <20130122162009.GB2072@gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4 To: "Bradley C. Kuszmaul" Return-path: Received: from mail-da0-f45.google.com ([209.85.210.45]:54073 "EHLO mail-da0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753636Ab3AVQGP (ORCPT ); Tue, 22 Jan 2013 11:06:15 -0500 Received: by mail-da0-f45.google.com with SMTP id w4so3309265dam.32 for ; Tue, 22 Jan 2013 08:06:14 -0800 (PST) Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Jan 22, 2013 at 09:34:59AM -0500, Bradley C. Kuszmaul wrote: > Hi, > > Do any of the ext file systems support hole punching? If so, do the > redhat distributions support it? Can someone provide an example of a > program that punches a hole in a file in an ext4 file system? Hello, Ext4 file system supports hole punching. But until now only extent-based file supports it. As far as I know, redhat distributions don't support hole punching. You can find a sample program from e2fsprogs which is in $e2fsprogs/conrib/fallocate.c. The latest fallocate(1) in util-linux also can be as a demo. Regards, - Zheng