From owner-freebsd-current@FreeBSD.ORG Mon Jul 4 16:55:33 2005 Return-Path: X-Original-To: current@freebsd.org Delivered-To: freebsd-current@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1EFEF16A41C for ; Mon, 4 Jul 2005 16:55:33 +0000 (GMT) (envelope-from andy@siliconlandmark.com) Received: from lexi.siliconlandmark.com (lexi.siliconlandmark.com [209.69.98.4]) by mx1.FreeBSD.org (Postfix) with ESMTP id C3A6843D48 for ; Mon, 4 Jul 2005 16:55:32 +0000 (GMT) (envelope-from andy@siliconlandmark.com) Received: from lexi.siliconlandmark.com (localhost [127.0.0.1]) by lexi.siliconlandmark.com (8.13.3/8.13.3) with ESMTP id j64GtTZA075019; Mon, 4 Jul 2005 12:55:29 -0400 (EDT) (envelope-from andy@siliconlandmark.com) Received: from localhost (andy@localhost) by lexi.siliconlandmark.com (8.13.3/8.13.3/Submit) with ESMTP id j64GtQli075016; Mon, 4 Jul 2005 12:55:29 -0400 (EDT) (envelope-from andy@siliconlandmark.com) X-Authentication-Warning: lexi.siliconlandmark.com: andy owned process doing -bs Date: Mon, 4 Jul 2005 12:55:26 -0400 (EDT) From: Andre Guibert de Bruet To: Yuriy Tsibizov In-Reply-To: <20050703112108.F474@free.home.local> Message-ID: <20050703124901.M80892@lexi.siliconlandmark.com> References: <20050703112108.F474@free.home.local> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Information: Please contact the ISP for more information X-SL-MailScanner: Found to be clean X-SL-SpamCheck: not spam, SpamAssassin (score=-2.54, required 6, autolearn=not spam, AWL 0.06, BAYES_00 -2.60) X-MailScanner-From: andy@siliconlandmark.com Cc: current@freebsd.org Subject: Re: Fatal trap 12 if you unmount detached umass device X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 04 Jul 2005 16:55:33 -0000 On Sun, 3 Jul 2005, Yuriy Tsibizov wrote: > It should be easy to reproduce if you don't follow > attach/mount/unmount/detach order: > > 1. attach usb storage device > 2. mount it > 3. detach it > 4. unmount it. This topic has been discussed at length on this list. Please search the archives. Conclusions that can be drawn: 1. Don't do that (If you're going to do it, try umount -f). 2a. Disabling write caching is the only way to get USB storage to be near hot-pluggable. Major write performance degradation is guaranteed. 2b. A non-trivial amount of work is needed to fix this. A suggested fix would be to rework the way that GEOM and CAM work together so that additional state information is passed (In the past, this topic has brought about two dozen Trek bikes, four bike racks and a lovely $COLOR-painted bikeshed). Andy /* Andre Guibert de Bruet * 6f43 6564 7020 656f 2e74 4220 7469 6a20 */ /* Code poet / Sysadmin * 636f 656b 2e79 5320 7379 6461 696d 2e6e */ /* GSM: +1 734 846 8758 * 5520 494e 2058 6c73 7565 6874 002e 0000 */ /* WWW: siliconlandmark.com * Tormenting bytes since 1980. */