From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1IUzX4-0005TL-Tc for qemu-devel@nongnu.org; Tue, 11 Sep 2007 02:47:34 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1IUzX2-0005Sm-FX for qemu-devel@nongnu.org; Tue, 11 Sep 2007 02:47:33 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1IUzX2-0005Sj-9s for qemu-devel@nongnu.org; Tue, 11 Sep 2007 02:47:32 -0400 Received: from mx20.gnu.org ([199.232.41.8]) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1IUzX1-0003e9-Nf for qemu-devel@nongnu.org; Tue, 11 Sep 2007 02:47:31 -0400 Received: from static-71-162-243-5.phlapa.fios.verizon.net ([71.162.243.5] helo=grelber.thyrsus.com) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1IUzX0-0007Wk-QB for qemu-devel@nongnu.org; Tue, 11 Sep 2007 02:47:30 -0400 From: Rob Landley Subject: Re: [Qemu-devel] copy on write-but-no-change Date: Tue, 11 Sep 2007 01:47:16 -0500 References: <46E0854D.8000301@lapo.it> <200709071040.15626.luke@dashjr.org> In-Reply-To: <200709071040.15626.luke@dashjr.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200709110147.16434.rob@landley.net> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Luke -Jr On Friday 07 September 2007 10:40:15 am Luke -Jr wrote: > I don't believe it's possible to make holes in sparse files explicitly. > The libc/OS only support it transparently when you jump to the end of a > file and begin writing there. Actually, I believe it should finally show up in the 2.6.23 kernel. Look for fadvise(FA_DEALLOCATE) http://lwn.net/Articles/226710/ Rob -- "One of my most productive days was throwing away 1000 lines of code." - Ken Thompson.