From owner-freebsd-scsi@FreeBSD.ORG Fri Feb 2 16:13:59 2007 Return-Path: X-Original-To: scsi@freebsd.org Delivered-To: freebsd-scsi@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 185DC16A400 for ; Fri, 2 Feb 2007 16:13:59 +0000 (UTC) (envelope-from mjacob@freebsd.org) Received: from ns1.feral.com (ns1.feral.com [192.67.166.1]) by mx1.freebsd.org (Postfix) with ESMTP id E6F7E13C478 for ; Fri, 2 Feb 2007 16:13:56 +0000 (UTC) (envelope-from mjacob@freebsd.org) Received: from ns1.feral.com (localhost [127.0.0.1]) by ns1.feral.com (8.13.8/8.13.8) with ESMTP id l12GDmCR019362; Fri, 2 Feb 2007 08:13:56 -0800 (PST) (envelope-from mjacob@freebsd.org) Received: from localhost (mjacob@localhost) by ns1.feral.com (8.13.8/8.13.8/Submit) with ESMTP id l12GDmkV019359; Fri, 2 Feb 2007 08:13:48 -0800 (PST) (envelope-from mjacob@freebsd.org) X-Authentication-Warning: ns1.feral.com: mjacob owned process doing -bs Date: Fri, 2 Feb 2007 08:13:48 -0800 (PST) From: mjacob@freebsd.org To: Nate Lawson In-Reply-To: <45C2E7DB.30204@root.org> Message-ID: <20070202080329.L17850@ns1.feral.com> References: <20070123173026.E692416A4CD@hub.freebsd.org> <45B65710.4060607@root.org> <20070123105009.G41619@ns1.feral.com> <45B67401.9070102@samsco.org> <20070201150111.B77236@ns1.feral.com> <45C27965.1010803@samsco.org> <45C2E7DB.30204@root.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: scsi@freebsd.org Subject: Re: cvs commit: src/sys/cam/scsi scsi_da.c X-BeenThere: freebsd-scsi@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: mjacob@freebsd.org List-Id: SCSI subsystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 02 Feb 2007 16:13:59 -0000 > I think Windows actually never runs SYNC_CACHE unless you select "detach > device". Maybe for pluggable devices, but otherwise Windows uses SYNC_CACHE and FUA quite freely (and correctly). I'm uncomfortable with the notion that there is uncommitted data present in a device after a close that can be lost due to power lossage (or unpluggage). From a user application or filesystem point of view, this is an axiom violation that no OS should ever allow. >From a silly semantic point of view to get around this, we should still support and require SYNC_CACHE on close except where devices don't support it (and any device that hangs on a SYNC_CACHE doesn't support it- period). On detach, devices that still need to have data commited via an opcode that looks remarkably like SYNC_CACHE can and should have that happen- with all the infrastructure changes that go along with allowing devices to be detached (w/o complaint) with a live command. Or have I missed something it what you're suggesting? -matt