Re: [Qemu-devel] [Qemu-block] block/nfs: Fine grained runtime options in nfs

[Eric Blake <eblake@redhat.com>]

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On 10/18/2016 08:33 AM, Kevin Wolf wrote:

>> I have successfully converted NFS block driver to use this set of
>> runtime opts which I think is the required condition to add
>> blockdev-add compatibility later. Also, since I do not have 'port' as
>> a runtime option, I can directly add blockdev-add compatibility after
>> this through qapi/block-core.json and will not have to go through the
>> tricky method we are implementing for NBD and SSH as there will be no
>> use of InetSocketAddress. Right?
> 
> Yes, InetSocketAddress is what makes things a bit tricky, and it doesn't
> seem to be useful with the API we get from libnfs, so just directly
> taking a host name should be okay. Then this one should be easier than
> SSH.
> 
> Eric, do you agree, or do you think we should take into account that
> libnfs might be extended one day to work on any socket?

Ideally, we want the valid JSON for ssh to be a subset of the valid JSON
for either InetSocketAddress, or for a flat counterpart (what we did for
gluster).  I kind of like the flat counterpart idea.  Yes, that probably
means we need to create a new QAPI type (comparable to the existing
types, but omitting port), rather than being able to reuse one; but as
long as the parameters are spelled the same, backwards-compatibility
states that we can later add fields, and that any two structs with
identical fields can be merged into one struct without breaking
backwards compatibility.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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