Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752524Ab2H3WDu (ORCPT ); Thu, 30 Aug 2012 18:03:50 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:44240 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751660Ab2H3WDt (ORCPT ); Thu, 30 Aug 2012 18:03:49 -0400 Date: Thu, 30 Aug 2012 15:03:48 -0700 From: Andrew Morton To: paul.clements@steeleye.com Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] [RESEND] add discard support to nbd Message-Id: <20120830150348.287bfa2f.akpm@linux-foundation.org> In-Reply-To: <503e0dde.ssYktQsJ5nYlhlQB%paul.clements@steeleye.com> References: <503e0dde.ssYktQsJ5nYlhlQB%paul.clements@steeleye.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 879 Lines: 24 On Wed, 29 Aug 2012 08:41:02 -0400 paul.clements@steeleye.com wrote: > Description: This patch adds discard support to nbd. When the nbd client > system receives a discard request, this will be passed along to the nbd > server system, where the nbd-server will respond by performing: > fallocate(.. FALLOC_FL_PUNCH_HOLE ..) > > To punch a hole in the backend storage, which is no longer needed. > What happens if the user is running an older server? I is it possible that because the old server didn't set NBD_FLAG_SEND_TRIM, the user's screen gets filled with WARN_ONs? Anyway, please make sure this combination was tested! -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/