[Libguestfs] [PATCH v4 0/3] v2v: Add -o rhv-upload output mode.

[Eric Blake]

On 03/14/2018 02:04 PM, Richard W.M. Jones wrote:

> I don't think we really need trim or flush.  They're only minor
> optimizations.  Zero is the one which is required.
> 
> FWIW NBD allows you to flush ranges or flush the whole disk, in case
> that matters (your proposal only allows you to flush the whole disk).

No, for now, NBD requires flush to be sent with parameters offset=0 
length=0 for flushing the entire disk.  Non-zero parameters for flushing 
only a range of the disk is reserved for future expansion, if someone 
actually has a use case for it.  nbdkit doesn't expose ranges to the 
.flush callback.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org