Re: In-kernel units for block numbers, etc ...

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Sat, 28 Nov 2015 22:34:25 +0100
    From:        Michael van Elst <mlelstv%serpens.de@localhost>
    Message-ID:  <20151128213424.GC6812%serpens.de@localhost>

  | > that would at least allow data to be recovered, by default, from
  | > the wrong sized media.

There's no reason there could not be a userland tool that would read
the underlying device and decrypt it (either writing back an unencrypted
filesys, or copying the data to another device/file).

  | I'm not really convinced that such half-compatibility is useful.

Nor am I

  | For recovery you always have vnd which can simulate any geometry.

I havem't looked carefully yet, but does vnd have the RMW behaviour to
allow an emulated small sector drive to exist on a big sector underlying.
I can see that it works if VNF_USE_VN_RDWR gets set (sparse file, weird
underlying device, ...) but I don't see anything that validates the
sector sizes (but I might just be missing it.)


kre