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From d56be1addb6f2a696f59e8971d0874a3e0d80ec7 Mon Sep 17 00:00:00 2001
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From: Ludwig Krispenz <lkrispen@redhat.com>
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Date: Wed, 20 Mar 2019 12:00:42 +0100
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Subject: [PATCH 4/4] Ticket 50265: the warning about skew time could last
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forever
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Bug: if the local system time is set back more than 300 seconds
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a worning about too much time skew is logged and the sampled
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time is updated. This adjustment is done at every write operation
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and can increase the time skew and be logged infinitely
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Fix: the intention of the adjustment was to avoid a roll over of seq_num
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if the sampled time is not increased for more than 65k oberations.
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But this is already handled with an explicite check for seq_num
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rollover. The extra adjustment for negative time skew can be removed.
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Reviewed by: Thierry, William. Thanks.
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---
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ldap/servers/slapd/csngen.c | 22 +++++++---------------
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1 file changed, 7 insertions(+), 15 deletions(-)
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diff --git a/ldap/servers/slapd/csngen.c b/ldap/servers/slapd/csngen.c
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index 3afc9176b..68dbbda8e 100644
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--- a/ldap/servers/slapd/csngen.c
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+++ b/ldap/servers/slapd/csngen.c
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@@ -191,22 +191,14 @@ csngen_new_csn(CSNGen *gen, CSN **csn, PRBool notify)
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slapi_rwlock_unlock(gen->lock);
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return rc;
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}
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- } else if (delta < -300) {
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- /*
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- * The maxseqnum could support up to 65535 CSNs per second.
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- * That means that we could avoid duplicated CSN's for
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- * delta up to 300 secs if update rate is 200/sec (usually
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- * the max rate is below 20/sec).
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- * Beyond 300 secs, we advance gen->state.sampled_time by
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- * one sec to recycle seqnum.
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- */
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- slapi_log_err(SLAPI_LOG_WARNING, "csngen_new_csn", "Too much time skew (%d secs). Current seqnum=%0x\n", delta, gen->state.seq_num);
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- rc = _csngen_adjust_local_time(gen, gen->state.sampled_time + 1);
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- if (rc != CSN_SUCCESS) {
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- slapi_rwlock_unlock(gen->lock);
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- return rc;
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- }
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}
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+ /* if (delta < 0) this means the local system time was set back
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+ * the new csn will be generated based on sampled time, which is
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+ * ahead of system time and previously generated csns.
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+ * the time stamp of the csn will not change until system time
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+ * catches up or is corrected by remote csns.
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+ * But we need to ensure that the seq_num does not overflow.
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+ */
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if (gen->state.seq_num == CSN_MAX_SEQNUM) {
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slapi_log_err(SLAPI_LOG_INFO, "csngen_new_csn", "Sequence rollover; "
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--
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2.17.2
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