Re: qemu-img convert vs writing another copy tool

[Richard W.M. Jones]

On Fri, Jan 24, 2020 at 09:55:55AM +0000, Richard W.M. Jones wrote:
> On Thu, Jan 23, 2020 at 01:21:28PM -0600, Eric Blake wrote:
> > Could we also teach this to parse 'qemu-img map --output=json'
> > format? And/or add 'qemu-img map --output=XYZ' (different from the
> > current --output=human') that gives sufficient information?  (Note:
> > --output=human is NOT suitable for extent lists - it intentionally
> > outputs only the data portions, and in so doing coalesces 'hole' and
> > 'hole,zero' segments to be indistinguishable).
> 
> If qemu-img doesn't have the data (we have to get it from
> another source), is the output of qemu-img map relevant?

I can see that we might use this to transfer a map from one qemu
source to another, which could be useful.  Unfortunately nbdkit
doesn't link to any libraries that can read JSON at the moment :-(
But certainly something to keep in mind for the future.

Rich.

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