Re: [PATCH dlm/next 11/12] dlm: add nldlm net-namespace aware UAPI

Jakub Kicinski
2024-08-19T22:12:29Z

On Mon, 19 Aug 2024 14:37:41 -0400 Alexander Aring wrote:
> Recent patches introduced support to separate DLM lockspaces on a per
> net-namespace basis. Currently the file based configfs mechanism is used
> to configure parts of DLM. Due the lack of namespace awareness (and it's
> probably complicated to add support for this) in configfs we introduce a
> socket based UAPI using "netlink". As the DLM subsystem offers now a
> config layer it can simultaneously being used with configfs, just that
> nldlm is net-namespace aware.
>
> Most of the current configfs functionality that is necessary to
> configure DLM is being adapted for now. The nldlm netlink interface
> offers also a multicast group for lockspace events NLDLM_MCGRP_EVENT.
> This event group can be used as alternative to the already existing udev
> event behaviour just it only contains DLM related subsystem events.
>
> Attributes e.g. nodeid, port, IP addresses are expected from the user
> space to fill those numbers as they appear on the wire. In case of DLM
> fields it is using little endian byte order.
>
> The dumps are being designed to scale in future with high numbers of
> members in a lockspace. E.g. dump members require an unique lockspace
> identifier (currently only the name) and nldlm is using a netlink dump
> behaviour to be prepared if all entries may not fit into one netlink
> message.

Did you consider using the YAML spec stuff to code gen the policies
and make user space easier?