DM_snapshot_cow filesystem (dmsetup create snapshot)

[Mr Dash Four <mr.dash.four@xxxxxxxxxxxxxx>]

As part of my livecd data structure dmsetup is used to create a snapshot 
containing xz-compressed root combined with copy-on-write ram-based 
overlay.

The way as I understand it, the ram-based overlay contains only the 
"chunks" of data which is changed. Is there a way - in terms of a tool 
or by any other means - to look at this overlay to see what data has 
been changed exactly?

I have tried, rather naively as it turned out, to mount the ram-based 
overlay but received  "unknown filesystem type 'DM_snapshot_cow'" error 
message, which makes me thing that the data structure is unique somehow 
and private to the device mapper.

One other thing - my dmsetup man page is from 2006 (created some 5 years 
ago) even though I am using the latest device-mapper package (1.02.63 I 
believe) and this man page does not contain any information on dmsetup 
create snapshot format, which is very annoying. Is there an updated 
version of the man page I could look at?

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