From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtpng2.m.smailru.net (smtpng2.m.smailru.net [94.100.179.3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 75801469719 for ; Sat, 7 Nov 2020 19:45:38 +0300 (MSK) From: Vladislav Shpilevoy Date: Sat, 7 Nov 2020 17:45:31 +0100 Message-Id: <7ef30635b68970d001065f233ff83e6e292bada1.1604767356.git.v.shpilevoy@tarantool.org> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Tarantool-patches] [PATCH 1/2] raft: fix crash on sm restart during WAL write List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: tarantool-patches@dev.tarantool.org, sergepetrenko@tarantool.org, avtikhon@tarantool.org Raft state machine crashed if was restarted during a WAL write being in progress. When the machine was started, it didn't assume there still can be a not finished WAL write from the time it was enabled earlier. The patch makes it continue waiting for the write end. Part of #5506 --- src/box/raft.c | 13 ++++- .../gh-5506-election-on-off.result | 55 +++++++++++++++++++ .../gh-5506-election-on-off.test.lua | 31 +++++++++++ test/replication/suite.cfg | 1 + test/replication/suite.ini | 2 +- 5 files changed, 98 insertions(+), 4 deletions(-) create mode 100644 test/replication/gh-5506-election-on-off.result create mode 100644 test/replication/gh-5506-election-on-off.test.lua diff --git a/src/box/raft.c b/src/box/raft.c index 914b0d68f..3a99a0f26 100644 --- a/src/box/raft.c +++ b/src/box/raft.c @@ -857,13 +857,20 @@ raft_sm_start(void) { say_info("RAFT: start state machine"); assert(!ev_is_active(&raft.timer)); - assert(!raft.is_write_in_progress); assert(!raft.is_enabled); assert(raft.state == RAFT_STATE_FOLLOWER); raft.is_enabled = true; raft.is_candidate = raft.is_cfg_candidate; - if (!raft.is_candidate) { - /* Nop. */; + if (raft.is_write_in_progress) { + /* + * Nop. If write is in progress, the state machine is frozen. It + * is continued when write ends. + */ + } else if (!raft.is_candidate) { + /* + * Nop. When a node is not a candidate, it can't initiate + * elections anyway, so it does not need to monitor the leader. + */ } else if (raft.leader != 0) { raft_sm_wait_leader_dead(); } else { diff --git a/test/replication/gh-5506-election-on-off.result b/test/replication/gh-5506-election-on-off.result new file mode 100644 index 000000000..1a718396f --- /dev/null +++ b/test/replication/gh-5506-election-on-off.result @@ -0,0 +1,55 @@ +-- test-run result file version 2 +test_run = require('test_run').new() + | --- + | ... + +old_election_mode = box.cfg.election_mode + | --- + | ... +old_replication_timeout = box.cfg.replication_timeout + | --- + | ... + +-- +-- gh-5506: Raft state machine crashed in case there was a WAL write in +-- progress, and Raft was disabled + enabled back immediately. It didn't assume +-- that there can be a not finished WAL write when Raft is just enabled. +-- + +-- Start a WAL write and wait when it starts. +box.error.injection.set("ERRINJ_WAL_DELAY_COUNTDOWN", 0) + | --- + | - ok + | ... +box.cfg{ \ + election_mode = 'candidate', \ + replication_timeout = 0.1, \ +} + | --- + | ... +test_run:wait_cond(function() \ + return box.error.injection.get("ERRINJ_WAL_DELAY") \ +end) + | --- + | - true + | ... + +-- Restart the state machine. It should notice the not finished WAL write and +-- continue waiting. +box.cfg{election_mode = 'off'} + | --- + | ... +box.cfg{election_mode = 'candidate'} + | --- + | ... +box.error.injection.set("ERRINJ_WAL_DELAY", false) + | --- + | - ok + | ... + +box.cfg{ \ + election_mode = old_election_mode, \ + replication_timeout = old_replication_timeout, \ +} + | --- + | ... diff --git a/test/replication/gh-5506-election-on-off.test.lua b/test/replication/gh-5506-election-on-off.test.lua new file mode 100644 index 000000000..290408f06 --- /dev/null +++ b/test/replication/gh-5506-election-on-off.test.lua @@ -0,0 +1,31 @@ +test_run = require('test_run').new() + +old_election_mode = box.cfg.election_mode +old_replication_timeout = box.cfg.replication_timeout + +-- +-- gh-5506: Raft state machine crashed in case there was a WAL write in +-- progress, and Raft was disabled + enabled back immediately. It didn't assume +-- that there can be a not finished WAL write when Raft is just enabled. +-- + +-- Start a WAL write and wait when it starts. +box.error.injection.set("ERRINJ_WAL_DELAY_COUNTDOWN", 0) +box.cfg{ \ + election_mode = 'candidate', \ + replication_timeout = 0.1, \ +} +test_run:wait_cond(function() \ + return box.error.injection.get("ERRINJ_WAL_DELAY") \ +end) + +-- Restart the state machine. It should notice the not finished WAL write and +-- continue waiting. +box.cfg{election_mode = 'off'} +box.cfg{election_mode = 'candidate'} +box.error.injection.set("ERRINJ_WAL_DELAY", false) + +box.cfg{ \ + election_mode = old_election_mode, \ + replication_timeout = old_replication_timeout, \ +} diff --git a/test/replication/suite.cfg b/test/replication/suite.cfg index 8fd62fdb8..f2addebda 100644 --- a/test/replication/suite.cfg +++ b/test/replication/suite.cfg @@ -16,6 +16,7 @@ "gh-4424-misc-orphan-on-reconfiguration-error.test.lua": {}, "gh-5426-election-on-off.test.lua": {}, "gh-5433-election-restart-recovery.test.lua": {}, + "gh-5506-election-on-off.test.lua": {}, "once.test.lua": {}, "on_replace.test.lua": {}, "status.test.lua": {}, diff --git a/test/replication/suite.ini b/test/replication/suite.ini index 6136c934f..34ee32550 100644 --- a/test/replication/suite.ini +++ b/test/replication/suite.ini @@ -3,7 +3,7 @@ core = tarantool script = master.lua description = tarantool/box, replication disabled = consistent.test.lua -release_disabled = catch.test.lua errinj.test.lua gc.test.lua gc_no_space.test.lua before_replace.test.lua qsync_advanced.test.lua qsync_errinj.test.lua quorum.test.lua recover_missing_xlog.test.lua sync.test.lua long_row_timeout.test.lua gh-4739-vclock-assert.test.lua gh-4730-applier-rollback.test.lua gh-5140-qsync-casc-rollback.test.lua gh-5144-qsync-dup-confirm.test.lua gh-5167-qsync-rollback-snap.test.lua +release_disabled = catch.test.lua errinj.test.lua gc.test.lua gc_no_space.test.lua before_replace.test.lua qsync_advanced.test.lua qsync_errinj.test.lua quorum.test.lua recover_missing_xlog.test.lua sync.test.lua long_row_timeout.test.lua gh-4739-vclock-assert.test.lua gh-4730-applier-rollback.test.lua gh-5140-qsync-casc-rollback.test.lua gh-5144-qsync-dup-confirm.test.lua gh-5167-qsync-rollback-snap.test.lua gh-5506-election-on-off.test.lua config = suite.cfg lua_libs = lua/fast_replica.lua lua/rlimit.lua use_unix_sockets = True -- 2.21.1 (Apple Git-122.3)