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From d56be1addb6f2a696f59e8971d0874a3e0d80ec7 Mon Sep 17 00:00:00 2001
From: Ludwig Krispenz <lkrispen@redhat.com>
Date: Wed, 20 Mar 2019 12:00:42 +0100
Subject: [PATCH 4/4] Ticket 50265: the warning about skew time could last
 forever

Bug: if the local system time is set back more than 300 seconds
	a worning about too much time skew is logged and the sampled
	time is updated. This adjustment is done at every write operation
	and can increase the time skew and be logged infinitely

Fix: the intention of the adjustment was to avoid a roll over of seq_num
	if the sampled time is not increased for more than 65k oberations.
	But this is already handled with an explicite check for seq_num
	rollover. The extra adjustment for negative time skew can be removed.

Reviewed by: Thierry, William. Thanks.
---
 ldap/servers/slapd/csngen.c | 22 +++++++---------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/ldap/servers/slapd/csngen.c b/ldap/servers/slapd/csngen.c
index 3afc9176b..68dbbda8e 100644
--- a/ldap/servers/slapd/csngen.c
+++ b/ldap/servers/slapd/csngen.c
@@ -191,22 +191,14 @@ csngen_new_csn(CSNGen *gen, CSN **csn, PRBool notify)
             slapi_rwlock_unlock(gen->lock);
             return rc;
         }
-    } else if (delta < -300) {
-        /*
-         * The maxseqnum could support up to 65535 CSNs per second.
-         * That means that we could avoid duplicated CSN's for
-         * delta up to 300 secs if update rate is 200/sec (usually
-         * the max rate is below 20/sec).
-         * Beyond 300 secs, we advance gen->state.sampled_time by
-         * one sec to recycle seqnum.
-         */
-        slapi_log_err(SLAPI_LOG_WARNING, "csngen_new_csn", "Too much time skew (%d secs). Current seqnum=%0x\n", delta, gen->state.seq_num);
-        rc = _csngen_adjust_local_time(gen, gen->state.sampled_time + 1);
-        if (rc != CSN_SUCCESS) {
-            slapi_rwlock_unlock(gen->lock);
-            return rc;
-        }
     }
+    /* if (delta < 0) this means the local system time was set back
+     * the new csn will be generated based on sampled time, which is
+     * ahead of system time and previously generated csns.
+     * the time stamp of the csn will not change until system time
+     * catches up or is corrected by remote csns.
+     * But we need to ensure that the seq_num does not overflow.
+     */
 
     if (gen->state.seq_num == CSN_MAX_SEQNUM) {
         slapi_log_err(SLAPI_LOG_INFO, "csngen_new_csn", "Sequence rollover; "
-- 
2.17.2