Hi,

On Mon, Sep 30, 2024 at 4:14 PM Alexander Aring [off-list ref] 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.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
 Documentation/netlink/specs/nldlm.yaml |  438 ++++++++
 fs/dlm/Makefile                        |    2 +
 fs/dlm/config.c                        |   20 +-
 fs/dlm/dlm_internal.h                  |    4 +
 fs/dlm/lockspace.c                     |   13 +-
 fs/dlm/netlink2.c                      | 1330 ++++++++++++++++++++++++

and this file shouldn't be there anymore. Will be dropped in v3.

- Alex