[PATCH 0/4] Abort vinyl transactions before switching to ro

[Vladimir Davydov <vdavydov.dev@gmail.com>]

In contrast to memtx, vinyl transactions may yield, which opens a time
window for the instance to switch to read-only mode. Since we check ro
flag only before executing a dml request, nothing prevents a transaction
from committing in such a case. This breaks master-replica switching
logic implemented by one of our customers, which justifiably assumes
that no local writes are allowed on an instance once box.cfg{read_only}
returns.

Fix this by forcefully aborting all local rw transactions in vinyl
before switching to read-only mode.

https://github.com/tarantool/tarantool/issues/4016
https://github.com/tarantool/tarantool/commits/dv/gh-4016-vy-abort-writers-for-ro

This patch set is an alternative approach to the fix proposed by Georgy,
for more details see discussion started at:

https://www.freelists.org/post/tarantool-patches/PATCH-Do-not-enable-commit-if-read-only-true

Vladimir Davydov (4):
  vinyl: rename tx statement begin/rollback routines
  vinyl: add tx to writers list in begin_statement engine callback
  engine: add switch_to_ro callback
  vinyl: abort rw transactions when instance switches to ro

 src/box/blackhole.c        |  1 +
 src/box/box.cc             |  7 ++++
 src/box/engine.c           | 14 ++++++++
 src/box/engine.h           | 13 ++++++++
 src/box/memtx_engine.c     |  1 +
 src/box/sysview.c          |  1 +
 src/box/vinyl.c            | 18 +++++++----
 src/box/vy_tx.c            | 34 +++++++++++++++++---
 src/box/vy_tx.h            | 35 +++++++++++++-------
 test/vinyl/errinj.result   | 76 +++++++++++++++++++++++++++++++++++++++++++
 test/vinyl/errinj.test.lua | 30 +++++++++++++++++
 test/vinyl/misc.result     | 80 ++++++++++++++++++++++++++++++++++++++++++++++
 test/vinyl/misc.test.lua   | 39 ++++++++++++++++++++++
 13 files changed, 327 insertions(+), 22 deletions(-)

-- 
2.11.0