From e0750262b899506649fb65592ce645129edc2687 Mon Sep 17 00:00:00 2001 From: Serge Petrenko Date: Thu, 13 Feb 2020 02:33:44 +0300 Subject: [PATCH] wal: warn when trying to write a record with a broken lsn There is an assertion in vclock_follow `lsn > prev_lsn`, which doesn't fire in release builds, of course. Let's at least warn the user on an attempt to write a record with a duplicate or otherwise broken lsn, and not follow such an lsn. Follow-up #4739 --- src/box/wal.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/src/box/wal.c b/src/box/wal.c index ac977c16e911..27bff662a3bd 100644 --- a/src/box/wal.c +++ b/src/box/wal.c @@ -951,9 +951,20 @@ wal_assign_lsn(struct vclock *vclock_diff, struct vclock *base, (*row)->tsn = tsn; (*row)->is_commit = row == end - 1; } else { - vclock_follow(vclock_diff, (*row)->replica_id, - (*row)->lsn - vclock_get(base, - (*row)->replica_id)); + int64_t diff = (*row)->lsn - vclock_get(base, (*row)->replica_id); + if (diff <= vclock_get(vclock_diff, + (*row)->replica_id)) { + say_crit("Attempt to write a broken LSN to WAL:" + " replica id: %d, confirmed lsn: %d," + " new lsn %d", (*row)->replica_id, + vclock_get(base, (*row)->replica_id) + + vclock_get(vclock_diff, + (*row)->replica_id), + (*row)->lsn); + assert(false); + } else { + vclock_follow(vclock_diff, (*row)->replica_id, diff); + } } } }