[lug] Convertion of ext4 Sparse Files

[stimits at comcast.net]

Hi,
 
I've been looking all over and am stumped. Files can be "sparse" where space isn't allocated until needed, and it is easy to create a sparse file. What I'm wondering...and am stumped about...there must be a way to take an image and convert it back to non-sparse...but how?
 
cp with "--sparse=never" does not work (I'm trying on Fedora 23 through 27, plus Ubuntu 16.04). This may be a property of the file in question though...some people will have a large file with content such as text...this is an embedded system dd of a partition...it is a binary image containing an ext4 partition which can be copied via dd back onto other embedded systems...but this was converted to sparse format to save space. Is there a way to take such an image and put it back to its original size without the sparse attribute?
 
Thanks!
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