removing external usb hdd without unmounting causes reboot?
smithi at nimnet.asn.au
Thu Jul 19 17:15:12 UTC 2007
On Thu, 19 Jul 2007, M. Warner Losh wrote:
> In message: <469F0B93.9020409 at gmx.de>
> "[LoN]Kamikaze" <LoN_Kamikaze at gmx.de> writes:
> : Oliver Fromme wrote:
> : > Momchil Ivanov wrote:
> : > > On Wednesday 18 July 2007 15:52:42 [LoN]Kamikaze wrote:
> : > > > Josh Paetzel wrote:
> : > > > > Yes, it's expected behavior. The workaround is to not unplug mounted
> : > > > > devices. (There's nothing special about USB here, if you unplugged an
> : > > > > IDE drive you'd get the same behavior)
> : > > >
> : > > > Wouldn't it make some sense not to panic if mounted devices that are in
> : > > > sync get removed? A few applications might get in trouble, but that's
> : > > > hardly a reason to bring a whole system down.
> : > >
> : > > I don`t know how things work, but shutting down the system when some
> : > > mounted fs is no longer present seems like the wrong thing to me.
> : >
> : > As Josh wrote, it's expected. The problem is known
> : > to exist for a long time already (probably as long
> : > as FreeBSD itself exists), and if there was an easy
> : > solution, certainly someone would have fixed it.
> : I remember on 5.3 I removed a mounted USB stick. The system did not panic, all
> : I had to do was to plug the stick back in to be able to unmount it. So the
> : behaviour has been more tolerant, in the past.
> I'm pretty sure that 5.3 panics when you do this. At least my 5.3
> machine at work did last time I tried it, which was just last week.
5.4 too. Now at 5.5-STABLE, on APM if it matters, I've had much fun
several times having the laptop, when on battery, suspend/resume with a
USB stick mounted on da0 (msdosfs or ufs) - without removing the device.
With rc.suspend kldunload'ing usb and rc.resume kldload'ing it (as
recommended for UHCI and, iirc, needed here) then on resume umass0
detaches & reattaches, but assigns the stick to da1. mount still shows
the da0sX mount. It doesn't panic unless / until something accesses
da0. So at least I usually get a window to reboot, the only way out.
Sure I've learned "don't do that" but it's painful when I forget ..
Might this new USB stack offer any relief to this need to unload/reload
usb on s/r, and if so keep hold of a mount (assuming the stick remains)?
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