[Cluster-devel] [PATCHv3 dlm/next 0/8] fs: dlm: introduce dlm re-transmission layer

[Alexander Aring <aahringo@redhat.com>]

Hi,

this is the final patch-series to make dlm reliable when re-connection
occurs. You can easily generate a couple of re-connections by running:

tcpkill -9 -i $IFACE port 21064

on your own to test these patches. At some time dlm will detect message
drops and will re-transmit messages if necessary. It introduces a new dlm
protocol behaviour and increases the dlm protocol version. I tested it
with SCTP as well and tried to be backwards compatible with dlm protocol
version 3.1. However I don't recommend at all to mix these versions
in a setup since dlm version 3.2 fixes long-term issues.

- Alex

changes since v3:
 - add comment about why queues are unbound
 - move rcu usage to version receive handler

changes since v2:
 - make timer handling pending only if messages are on air, the sync
   isn't quite correct there but doesn't need to be precise
 - use before() from tcp to check if seq is before other seq with
   respect of overflows
 - change srcu handling to hold srcu in all places where nodes are
   referencing - we should not get a disadvantage of holding that
   lock. We should update also lowcomms regarding to that.
 - add some WARN_ON() to check that nothing in send/recv is going
   anymore otherwise it's likely an issue.
 - add more future work regarding to fencing of nodes if over
   cluster manager timeout/bad seq happens
 - add note about missing length size check of tail payload
   (resource name length) regarding to the receive buffer
 - remove some include which isn't necessary in recoverd.c

Thanks to Paolo Abeni for his review and recommendations.

Alexander Aring (8):
  fs: dlm: public header in out utility
  fs: dlm: add more midcomms hooks
  fs: dlm: make buffer handling per msg
  fs: dlm: add functionality to re-transmit a message
  fs: dlm: move out some hash functionality
  fs: dlm: add union in dlm header for lockspace id
  fs: dlm: add reliable connection if reconnect
  fs: dlm: don't allow half transmitted messages

 fs/dlm/config.c       |    3 +-
 fs/dlm/dlm_internal.h |   35 +-
 fs/dlm/lock.c         |   14 +-
 fs/dlm/lockspace.c    |   14 +-
 fs/dlm/lowcomms.c     |  197 +++++--
 fs/dlm/lowcomms.h     |   23 +-
 fs/dlm/member.c       |   12 +-
 fs/dlm/midcomms.c     | 1307 ++++++++++++++++++++++++++++++++++++++++-
 fs/dlm/midcomms.h     |   10 +
 fs/dlm/rcom.c         |   63 +-
 fs/dlm/util.c         |   10 +-
 fs/dlm/util.h         |    2 +
 12 files changed, 1577 insertions(+), 113 deletions(-)

-- 
2.26.3