[Libguestfs] Cross-project NBD extension proposal: NBD_INFO_INIT_STATE

[Wouter Verhelst]

Hi,

On Mon, Feb 10, 2020 at 10:52:55PM +0000, Richard W.M. Jones wrote:
> But anyway ... could a flag indicating that the whole image is sparse
> be useful, either as well as NBD_INIT_SPARSE or instead of it?  You
> could use it to avoid an initial disk trim, which is something that
> mke2fs does:

Yeah, I think that could definitely be useful. I honestly can't see a
use for NBD_INIT_SPARSE as defined in this proposal; and I don't think
it's generally useful to have a feature if we can't think of a use case
for it (that creates added complexity for no benefit).

If we can find a reasonable use case for NBD_INIT_SPARSE as defined in
this proposal, then just add a third bit (NBD_INIT_ALL_SPARSE or
something) that says "the whole image is sparse". Otherwise, I think we
should redefine NBD_INIT_SPARSE to say that.

-- 
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