nbd: Create struct for tracking export info
The NBD Protocol is introducing some additional information
about exports, such as minimum request size and alignment, as
well as an advertised maximum request size. It will be easier
to feed this information back to the block layer if we gather
all the information into a struct, rather than adding yet more
pointer parameters during negotiation.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <
20170707203049.534-2-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>