removing external usb hdd without unmounting causes reboot?

[M. Warner Losh]

In message: <200707181942.45045.idiotbg at gmail.com>
            Momchil Ivanov <idiotbg at gmail.com> writes:
: On Wednesday 18 July 2007 19:34:06 Mark Linimon wrote:
: > On Wed, Jul 18, 2007 at 10:05:59AM -0700, Jeremy Chadwick wrote:
: > > Bottom line here is that the kernel panics when removing a USB device
: > > that has filesystems mounted.
: >
: > s/USB //
: 
: Just a dumb question: what does "umount -f" does? And doing something like 
: that when a fs goes away shouldn`t fix it?

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.

: If the problem is in general with a file system, regardless of the provider, 
: then what does one do when a mounted smbfs becomes unavailable due to remote 
: host down, no route to host or some other network related problems? Same 
: question for NFS mounted filesystems?

In those cases, the device doesn't go away.  Just the remote host.
This is a big difference.

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.

Warner