Date: Fri, 20 Jul 2007 15:15:13 -0700 From: "David Schwartz" <davids@webmaster.com> To: <idiotbg@gmail.com> Cc: freebsd-stable@FreeBSD.org Subject: RE: removing external usb hdd without unmounting causes reboot? Message-ID: <MDEHLPKNGKAHNMBLJOLKIEKOFHAC.davids@webmaster.com> In-Reply-To: <20070719.085101.-1860900987.imp@bsdimp.com>
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> It won't fix it. The problem is dangling pointers to devices that no > longer exist. And like all dangling references after 'free' you get > bad thing happening. > Believe me, if it were easy, it would have been fixed. If it was > moderate to fix, it would have been fixed. It is a hard problem that > people have put lots of hours into to try to resolve. To imply > otherwise is really insulting to all those people (myself include) > that have tried to fix this. There is a simple but ugly way to fix it, similar to what the FireWire layer does. The idea is for the USB layer to create a "device that never goes away" when it first sees the stick and pass that "device that never goes away" to the other layers. Even if the storage device is removed, the device still does not go away. The virtual device can generate errors if the physical device is missing. The virtual device can be cleaned up when the device is unmounted. This will ensure that the 'umount -f' process generates errors (which it will ignore) rather than crashes (which are somewhat harder to ignore). DS
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