removing external usb hdd without unmounting causes reboot?
olli at lurza.secnetix.de
Mon Jul 23 14:16:03 UTC 2007
Stefan Esser wrote:
> Oliver Fromme wrote:
> > Momchil Ivanov wrote:
> > > 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 have to check this, but AFAIK this problem exists only for
> devices/partitions that are mounted R/W. Do you happen to
> know this? (I can not risk to crash my box right now for a
> test ;-)
I'm afraid the problem affects _all_ mounts, including
> There once was an autofs implementation, but IIRC it has
> later been removed. It could not only automatically mount
> removable media, but it could also help with the problem
> of devices that are rarely written to, but still mounted
> R/W just in case for easy write-access.
> Long time ago I had the idea that a clean file system could
> be mounted R/O after a short delay. When all dirty buffers
> are flushed, the device could be forcefully disconnected
> without causing inconsistencies in the kernel. If there are
> no open file descriptors, the super-block could be written
> with the "clean" flag set, to signal that no fsck is needed
> when the partition is mounted next time.
> Internally, the device can be treated as R/O, with the only
> exeption that an attempted write is not rejected, but that
> it instead triggers the change back to R/W operation (this
> means setting the in-RAM copy of the super-block to dirty
> before the write is allowed to proceed as normal).
That's a very interesting idea. Unfortunately it doesn't
solve the problem, because read-only mounts have the same
So, currently the best work-around is to use amd with a
very short timeout. Or simply remember to umount your
removable media manually.
Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
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