Stale mount on disconnected device: how to delete it?

[Nikos Ntarmos]

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On Tue, Dec 18, 2007 at 01:13:55AM +0100, Romain Tartière wrote:
> On Mon, Dec 17, 2007 at 10:32:48AM -0800, Yuri wrote :
> > In case of USB device (which device in question in this problem
> > happens to be) usbd can be used to mount it.
> > 
> > If attach/detach events trigger mount/unmount commands this problem
> > shouldn't exist. I didn't try though.
> 
> The problem is that the detach event can be caught only too late to
> unmount the device properly.  How may it be possible to sync a disk
> ``as soon as it is detached'' (that is when it is not physically
> connected to the computer anymore)?  Mounting the disk read-only may
> be a workaround, just as not caching writes (default behaviour of some
> versions of Windows) and syncing the disk all the time, but this is
> not as reliable as the mount system provided by Unix and Unix like
> operating systems.
> 
> AFAICR, this is the sole weakness of the FreeBSD operating system I
> know :)  And since it is, according to me, an operator error, the best
> we can do is to use the system as it was designed for ;)

Off the top of my head, what is wrong/hard with just logging a device
failure, discarding all remaining cached operations, and unmounting the
fs when a disk device goes missing? I understand that this is not a
viable solution for critical filesystems, but I can see nothing wrong
with this approach for removable devices and/or non-critical fs's.

Just my $0.02.

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Comment: Nikos Ntarmos <ntarmos at ceid.upatras.gr>

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