From owner-freebsd-stable@FreeBSD.ORG Sun Jul 22 13:23:47 2007 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D3B0616A41B for ; Sun, 22 Jul 2007 13:23:47 +0000 (UTC) (envelope-from freebsd@meijome.net) Received: from sigma.octantis.com.au (ns2.octantis.com.au [207.44.189.124]) by mx1.freebsd.org (Postfix) with ESMTP id 9EE8113C4B6 for ; Sun, 22 Jul 2007 13:23:47 +0000 (UTC) (envelope-from freebsd@meijome.net) Received: (qmail 20793 invoked from network); 22 Jul 2007 08:23:47 -0500 Received: from 203-206-233-219.dyn.iinet.net.au (HELO localhost) (203.206.233.219) by sigma.octantis.com.au with (DHE-RSA-AES256-SHA encrypted) SMTP; 22 Jul 2007 08:23:47 -0500 Date: Sun, 22 Jul 2007 23:23:41 +1000 From: Norberto Meijome To: "M. Warner Losh" Message-ID: <20070722232341.0bdfd6da@localhost> In-Reply-To: <20070721.204413.-432837168.imp@bsdimp.com> References: <200707190943.55428.idiotbg@gmail.com> <20070719.090250.1387160138.imp@bsdimp.com> <20070721110603.3878d933@localhost> <20070721.204413.-432837168.imp@bsdimp.com> X-Mailer: Claws Mail 2.10.0 (GTK+ 2.10.14; i386-portbld-freebsd6.2) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: LoN_Kamikaze@gmx.de, olli@lurza.secnetix.de, freebsd-stable@freebsd.org, idiotbg@gmail.com, josh@tcbug.org Subject: Re: removing external usb hdd without unmounting causes reboot? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 22 Jul 2007 13:23:47 -0000 On Sat, 21 Jul 2007 20:44:13 -0600 (MDT) "M. Warner Losh" wrote: > In message: <20070721110603.3878d933@localhost> > Norberto Meijome writes: > : On Thu, 19 Jul 2007 09:02:50 -0600 (MDT) > : "M. Warner Losh" wrote: > : > : > In message: <200707190943.55428.idiotbg@gmail.com> > : > Momchil Ivanov writes: > : > : What is then the reason for the kernel not being able to unmount a > : > : filesystem whose provider is no longer present? > : > > : > The problem is that the device driver has wound down, deallocated > : > memory, etc. Now the kernel comes along with stale references to the > : > device and panic ensues. It is really just that simple. There's no > : > replacement of the now-dead device with dead calls. > : > > : > And even if you fixed that, most of the file systems in the tree today > : > do not tolerate errors on writes at all and that also leads to > : > panics. This is why firewire freezes the I/Os rather than failing > : > them (and why umount -f on a firewire drive hangs). > : > : Please point me to the correct RTFM, because I feel this worth it :) > > src/sys/fs/..., src/sys/kern/... and src/sys/vm/... are your best bets. > > : Is there a reason why the kernel cannot check 'upwards' if a device > : is being used, ie mounted ? and prevent the unloading of the device > : driver ? > > Check, sure, it can check. But what does a simple check accomplish if > the filesystem panics if the underlying media returns an error? The > problem isn't as simple as just looking in one place or another, but > rather systemic in nature. > thanks Warner. What do you estimate is the cost (time, at least) to investigate and fix this issue? SoC project? 4 mth project? cheers, B _________________________ {Beto|Norberto|Numard} Meijome Anyone who isn't confused here doesn't really understand what's going on. I speak for myself, not my employer. Contents may be hot. Slippery when wet. Reading disclaimers makes you go blind. Writing them is worse. You have been Warned.