[Qemu-devel] [PATCH v6 0/7] NBD reconnect

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

Here is NBD reconnect. Previously, if connection failed all current
and future requests will fail. After the series, nbd-client driver
will try to reconnect unlimited times. During first @reconnect-delay
seconds of reconnecting all requests will wait for the connection,
and if it is established requests will be resent. After
@reconnect-delay period all requests will be failed (until successful
reconnect).

v4->v6:
 (some preparing patches from v4 was merged as v5)
01: new
02: new
03: - drop unused things
       - future states
       - future s/break/continue/
04: - fix typos
    - s/3.1/4.1/
    - set 0 as default
05: new
06: - new states and s/break/continue/ moved here from 03
    - drop NBDClientSession.receiving, as now in_flight
      requests used instread
    - add copyright
    - go to NBD_CLIENT_CONNECTING_NOWAIT immediately if
      reconnect_delay is 0 (so, reconnect_delay moved to
      NBDClientSession)
    - on close, do qemu_co_sleep_wake(client->connection_co),
      to not wait for reconnect loop iteration
    - handle state transition to QUIT during reconnect loop
      (assert(nbd_client_connecting(s)) was bad idea)
    - don't try to fail on protocol errors after
      nbd_client_connect, as we can't distinguish them
    - decrement in_flight around reconnect sleep to make
      it possible to drain and exit during it
      (v4 was based on something before in_flight logic
       introduced into nbd-client)
    - changed logic in nbd_client_attach_aio_context 
07: - refactor, using log and qmp_log
    - drop export name
    - drop strange try/except
    - add reconnect-delay option (as 0 is a default now)


Vladimir Sementsov-Ogievskiy (7):
  block/nbd-client: split connection_co start out of nbd_client_connect
  block/nbd-client: use non-blocking io channel for nbd negotiation
  block/nbd-client: move from quit to state
  block/nbd: add cmdline and qapi parameter reconnect-delay
  qemu-coroutine-sleep: introduce qemu_co_sleep_wake
  block/nbd-client: nbd reconnect
  iotests: test nbd reconnect

 qapi/block-core.json          |  12 +-
 block/nbd-client.h            |  15 +-
 include/block/nbd.h           |   3 +-
 include/qemu/coroutine.h      |   6 +
 block/nbd-client.c            | 416 +++++++++++++++++++++++++---------
 block/nbd.c                   |  16 +-
 nbd/client.c                  |  16 +-
 qemu-nbd.c                    |   2 +-
 util/qemu-coroutine-sleep.c   |  20 +-
 tests/qemu-iotests/249        |  63 +++++
 tests/qemu-iotests/249.out    |  10 +
 tests/qemu-iotests/group      |   1 +
 tests/qemu-iotests/iotests.py |   4 +
 13 files changed, 468 insertions(+), 116 deletions(-)
 create mode 100755 tests/qemu-iotests/249
 create mode 100644 tests/qemu-iotests/249.out

-- 
2.18.0