Re: [Libguestfs] [nbdkit PATCH v2 3/6] protocol: Support ESHUTDOWN error

The NBD specification was clarified to state that the server can send ESHUTDOWN at any time that it wants to inform the client that the server is about to close the connection and that all further commands will fail, to give the client a chance to first send NBD_CMD_DISC for a clean shutdown. While nbdkit does not (yet) directly send this errno, it is feasible that a plugin may want this error value preserved across the wire rather than converted to EINVAL. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt;