Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264195AbUDGUrY (ORCPT ); Wed, 7 Apr 2004 16:47:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264192AbUDGUrY (ORCPT ); Wed, 7 Apr 2004 16:47:24 -0400 Received: from Kiwi.CS.UCLA.EDU ([131.179.128.19]:49898 "EHLO kiwi.cs.ucla.edu") by vger.kernel.org with ESMTP id S264197AbUDGUrI (ORCPT ); Wed, 7 Apr 2004 16:47:08 -0400 To: Andrew Morton Cc: Andy Isaacson , bug-coreutils@gnu.org, linux-kernel@vger.kernel.org Subject: Re: dd PATCH: add conv=direct References: <20040406220358.GE4828@hexapodia.org> <20040406173326.0fbb9d7a.akpm@osdl.org> <20040407173116.GB2814@hexapodia.org> <20040407111841.78ae0021.akpm@osdl.org> From: Paul Eggert Date: Wed, 07 Apr 2004 13:46:31 -0700 In-Reply-To: <20040407111841.78ae0021.akpm@osdl.org> (Andrew Morton's message of "Wed, 7 Apr 2004 11:18:41 -0700") Message-ID: <87vfkbms7s.fsf@penguin.cs.ucla.edu> User-Agent: Gnus/5.1006 (Gnus v5.10.6) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 987 Lines: 21 Andrew Morton writes: > In 2.6 we do the check at open() and fcntl() time. In 2.4 we don't > fail until the actual I/O attempt. This raises the issue of what "dd conv=direct" should do in 2.4 kernels. I propose that it should report an error and exit, when the write fails, since conv=direct can't be implemented. The basic idea is that on systems that lack direct I/O, conv=direct should fail. Another issue with this patch: in Solaris, direct I/O is done by invoking directio(DIRECTIO_ON); see . Is Solaris direct I/O a direct analog to Linux direct I/O, or are there subtle differences in semantics that should be made visible to the users of GNU "dd"? - 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/