[PATCH v2 00/20] drbd: DRBD 9 rework

[Christoph Böhmwalder]

As discussed (context: [0]), here is our DRBD 9 rework series, intended
for linux-next via for-7.x/drbd.

This replays about 10-15 years of active out-of-tree development work
[1], depending on your way of counting. The out-of-tree module has
severely diverged from the in-tree version over the years, which is
what we are aiming to fix now.

Hopefully that somewhat excuses (or at least explains) the massive
diffs -- we've tried to come up with a way to group the changes by
topic, but I realize it's still not exactly trivial to review.

We've been polishing this series for a while now, and we have taken
great care to make it as "upstream-presentable" as possible. That said,
there are still probably imperfections. It's a start -- feedback
welcome!

The netlink interface has been reworked so that userspace is not
broken: the existing "drbd" generic netlink family keeps being served
at version 1, and this series does not touch its generated
serialization or its UAPI header.
Every shipped drbd-utils release therefore keeps working against this
driver. DRBD 9's own utilities speak a new family, "drbd2", written as
a YNL specification under Documentation/netlink/specs/ and following
current genetlink conventions; its generated code is checked in as
usual. The driver registers both families and translates each onto the
same wire-neutral core, so the multi-peer administration model is only
reachable through drbd2, while version-1 clients see the single-peer
semantics they expect.

The RDMA and load-balancing TCP (lb-tcp) transports are not part of
this series; they will be submitted separately once they have had the
same treatment. The rdma_ctrl_rcvbuf_size
and rdma_ctrl_sndbuf_size net options do remain in the UAPI: they are
generic transport options that are interpreted by whichever transport is
in use, so there is no reason to remove and later re-add them.

The base for these patches is for-7.4/block, plus a set of preparation
patches that were sent earlier but have not yet been applied [2].

As discussed, the goal is to get this applied to a for-7.x/drbd branch
so it can land in linux-next via block-next. After letting it mature
in linux-next for a while, it should go in via the block tree.

Thanks,
Christoph

[0] https://lore.kernel.org/linux-next/899e0337-9642-4ca6-9050-aeab14fa22ef@xxxxxxxxx/
[1] https://github.com/LINBIT/drbd
[2] https://lore.kernel.org/linux-block/20260923140608.1116713-1-christoph.boehmwalder@xxxxxxxxxx/


Changes since v1:
- New modern YNL-based drbd2 netlink family
- Compat layer that serves the old drbd v1 netlink family for userspace
  backward compatibility
- Dropped rdma and lb-tcp transports to reduce the diff size, these will
  be sent later
- Incoroporated review feedback from the previous series
- Many checkpatch/style fixes


Christoph Böhmwalder (20):
  drbd: mark as BROKEN during DRBD 9 rework
  drbd: extend wire protocol definitions for DRBD 9
  drbd: introduce DRBD 9 on-disk metadata format
  drbd: add transport layer abstraction
  drbd: add TCP transport implementation
  drbd: add DAX/PMEM support for metadata access
  drbd: add optional compatibility layer for DRBD 8.4
  drbd: add application/resync IO synchronization documentation
  drbd: rework sender for DRBD 9 multi-peer
  drbd: replace per-device state model with multi-peer data structures
  drbd: rewrite state machine for DRBD 9 multi-peer clusters
  drbd: rework activity log and bitmap for multi-peer replication
  drbd: rework request processing for DRBD 9 multi-peer IO
  drbd: rework module core for DRBD 9 transport and multi-peer
  drbd: rework receiver for DRBD 9 transport and multi-peer protocol
  drbd: rework the netlink core for DRBD 9
  drbd: serve the "drbd" genl family at version 1 for existing userspace
  drbd: add the "drbd2" genl family
  drbd: update monitoring interfaces for multi-peer topology
  drbd: remove BROKEN for DRBD

 .../application-resync-synchronization.rst    |   208 +
 .../admin-guide/blockdev/drbd/index.rst       |     1 +
 Documentation/netlink/specs/drbd2.yaml        |  2476 +++
 drivers/block/drbd/Kconfig                    |    43 +
 drivers/block/drbd/Makefile                   |     9 +-
 drivers/block/drbd/drbd2_nl_gen.c             |   748 +
 drivers/block/drbd/drbd2_nl_gen.h             |   107 +
 drivers/block/drbd/drbd_actlog.c              |  1267 +-
 drivers/block/drbd/drbd_bitmap.c              |  1989 +-
 drivers/block/drbd/drbd_config.h              |    44 +-
 drivers/block/drbd/drbd_dax_pmem.c            |   172 +
 drivers/block/drbd/drbd_dax_pmem.h            |    43 +
 drivers/block/drbd/drbd_debugfs.c             |  1721 +-
 drivers/block/drbd/drbd_debugfs.h             |     2 +
 drivers/block/drbd/drbd_int.h                 |  3748 ++--
 drivers/block/drbd/drbd_interval.c            |    37 +-
 drivers/block/drbd/drbd_interval.h            |   125 +-
 drivers/block/drbd/drbd_legacy_84.c           |   641 +
 drivers/block/drbd/drbd_legacy_84.h           |   129 +
 drivers/block/drbd/drbd_main.c                |  6680 +++++--
 drivers/block/drbd/drbd_meta_data.h           |   154 +
 drivers/block/drbd/drbd_nl.c                  |  9477 ++++++---
 drivers/block/drbd/drbd_nl.h                  |   390 +
 drivers/block/drbd/drbd_nl_84.c               |  3622 ++++
 drivers/block/drbd/drbd_nl_defaults.c         |   167 +
 drivers/block/drbd/drbd_nl_drbd2.c            |  2533 +++
 drivers/block/drbd/drbd_nl_types.h            |   388 +
 drivers/block/drbd/drbd_polymorph_printk.h    |    37 +-
 drivers/block/drbd/drbd_proc.c                |   327 +-
 drivers/block/drbd/drbd_protocol.h            |   614 +-
 drivers/block/drbd/drbd_receiver.c            | 16314 ++++++++++++----
 drivers/block/drbd/drbd_req.c                 |  3172 ++-
 drivers/block/drbd/drbd_req.h                 |   332 +-
 drivers/block/drbd/drbd_sender.c              |  4354 +++--
 drivers/block/drbd/drbd_state.c               |  8963 +++++++--
 drivers/block/drbd/drbd_state.h               |   326 +-
 drivers/block/drbd/drbd_state_change.h        |    80 +-
 drivers/block/drbd/drbd_strings.c             |   103 +-
 drivers/block/drbd/drbd_strings.h             |     4 +-
 drivers/block/drbd/drbd_transport.c           |   545 +
 drivers/block/drbd/drbd_transport.h           |   480 +
 drivers/block/drbd/drbd_transport_tcp.c       |  1746 ++
 drivers/block/drbd/drbd_transport_template.c  |   164 +
 include/uapi/linux/drbd.h                     |   299 +-
 include/uapi/linux/drbd2.h                    |  1012 +
 include/uapi/linux/drbd_limits.h              |   135 +-
 46 files changed, 58914 insertions(+), 17014 deletions(-)
 create mode 100644 Documentation/admin-guide/blockdev/drbd/application-resync-synchronization.rst
 create mode 100644 Documentation/netlink/specs/drbd2.yaml
 create mode 100644 drivers/block/drbd/drbd2_nl_gen.c
 create mode 100644 drivers/block/drbd/drbd2_nl_gen.h
 create mode 100644 drivers/block/drbd/drbd_dax_pmem.c
 create mode 100644 drivers/block/drbd/drbd_dax_pmem.h
 create mode 100644 drivers/block/drbd/drbd_legacy_84.c
 create mode 100644 drivers/block/drbd/drbd_legacy_84.h
 create mode 100644 drivers/block/drbd/drbd_meta_data.h
 create mode 100644 drivers/block/drbd/drbd_nl.h
 create mode 100644 drivers/block/drbd/drbd_nl_84.c
 create mode 100644 drivers/block/drbd/drbd_nl_defaults.c
 create mode 100644 drivers/block/drbd/drbd_nl_drbd2.c
 create mode 100644 drivers/block/drbd/drbd_nl_types.h
 create mode 100644 drivers/block/drbd/drbd_transport.c
 create mode 100644 drivers/block/drbd/drbd_transport.h
 create mode 100644 drivers/block/drbd/drbd_transport_tcp.c
 create mode 100644 drivers/block/drbd/drbd_transport_template.c
 create mode 100644 include/uapi/linux/drbd2.h


base-commit: c3bcce56763375946bc31a4dac859b4b4cc07ccd
-- 
2.55.0