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Re: usb flash drive removal (Re: Desktop NetBSD needs your help)



On Sat, Feb 14, 2009 at 06:13:26PM -0500, Steven M. Bellovin wrote:
> I have a powerd script that forcibly unmounts and unconfigures cgd
> drive on suspend events.

Yeah, that's a fine start for present infrastructure. But I'm talking
about leaving the fs mounted, device suspended without keys, in a
state that blocks IO requests (or potentially errors some). 

Together with this at the device level, there would also be ubc/vfs
level changes to make it work most effectively. These would involve
either also clearing cache (for sensitive data), or forcing some
(meta)data to be cached so it's accessible until/for unsuspend, or
holding back writes before the device layer (e.g. deferring atime
updates).  Again, a lot of parallels with power management objectives
(like avoiding spinning up 'normal' disks).

FYI, cgd(4) zeros its own key data, but nothing from ubc cache or
other layers.

--
Dan.

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