Stale mount on disconnected device: how to delete it?

[Antony Mawer]

On 18/12/2007 5:09 AM, Peter Jeremy wrote:
> On Mon, Dec 17, 2007 at 03:07:02AM -0800, Yuri wrote:
>> I had USB camera connected and recognized as umass0 and mounted as /mnt/camera
>> on /dev/da0s1.
>>
>> Camera was disconnected while it was still mounted.
> 
> This triggers known and extremely painful to fix bugs in FreeBSD.
> Your best work-around is to use ports/emulators/mtools rather than
> mount_msdosfs to to access removable devices.

Every time this comes up it's branded with the "really hard to fix" 
message, but I seem to recall the last time this came up Matt Dillon 
chimed in and said he'd managed to fix it in Dragonfly without too much 
pain.

I had a browse back a while ago at the commits on DF to try and pinpoint 
the changes that were required to see how practical they were to bring 
across to FreeBSD; I don't profess to be an expert and have yet to 
investigate the changes in any detail, but these were the commits I 
identified:

     http://freshbsd.org/2007/06/14/03/55/27
     http://freshbsd.org/2007/06/17/06/08/52
     http://freshbsd.org/2007/06/14/02/09/30
     http://freshbsd.org/2007/06/13/21/58/38
     http://freshbsd.org/2007/06/13/21/53/39

If someone else is interested in looking at this, it may provide a 
useful starting point...

--Antony