Write protect access on USB port

[Amit <amit.uttam@gmail.com>]

Hello,

I would like to block write access by default to all drives plugged in
to my USB port (a specific USB port). This capability would probably be
at the kernel level to be effective.

Doing research on LWN.net, I noticed the following sentence by Corbet:

(http://lwn.net/Articles/428533/):

Enforcing read-only: The block layer has a mechanism by which a driver
can mark a specific device (or partition) as being read-only. This flag
may be set if the physical device is write-locked; it can also be set by
higher-level code (the DM or MD layers, for example) when the
administrator creates a read-only device.

Any idea on how this is done?

Thanks,
Amit