From 1bbf30e1d326143c7d00dba972da8adbbcf66055 Mon Sep 17 00:00:00 2001
From: Kamoltat <ksirivad@redhat.com>
Date: Thu, 6 Apr 2023 17:36:55 +0000
Subject: [PATCH] mon/Monitor.cc: exit function if !osdmon()->is_writeable()

Problem:

In the function `maybe_go_degraded_stretch_mode()`
when `osdmon` is not writeable we shouldn't go into
`trigger_degraded_stretch_mode` because we will
crash at `ceph_assert(osdmon()->is_writeable())`.
The current code does not exit `maybe_go_degraded_stretch_mode()`
when we are waiting for `osdmon` to be writeable, therefore,
we crash.

Solution:

Exit the function by returning nothing after going into
`wait_for_writeable_ctx`, since at that point we would have
queued the context and all we have to do is wait for finish
context to execute `maybe_go_degraded_stretch_mode` again.

Also, added a bit of logging so that user is aware
when `osdmon` and `monmon` are not writeable.

We fix other parts of the monitor code that are missing
the return after `wait_for_writeable_ctx` and `wait_for_readable_ctx`
as well.

Fixes: https://tracker.ceph.com/issues/59271

Signed-off-by: Kamoltat <ksirivad@redhat.com>
(cherry picked from commit 7f7c2d51c60c58aeb031ec279a48910bc02444de)
---
 src/mon/Monitor.cc | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/mon/Monitor.cc b/src/mon/Monitor.cc
index e2b4a3109d7..e1e9ffd255a 100644
--- a/src/mon/Monitor.cc
+++ b/src/mon/Monitor.cc
@@ -6647,7 +6647,9 @@ void Monitor::try_engage_stretch_mode()
   dout(20) << __func__ << dendl;
   if (stretch_mode_engaged) return;
   if (!osdmon()->is_readable()) {
+    dout(20) << "osdmon is not readable" << dendl;
     osdmon()->wait_for_readable_ctx(new CMonEnableStretchMode(this));
+    return;
   }
   if (osdmon()->osdmap.stretch_mode_enabled &&
       monmap->stretch_mode_enabled) {
@@ -6730,12 +6732,15 @@ void Monitor::go_recovery_stretch_mode()
   }
   
   if (!osdmon()->is_readable()) {
+    dout(20) << "osdmon is not readable" << dendl;
     osdmon()->wait_for_readable_ctx(new CMonGoRecovery(this));
     return;
   }
 
   if (!osdmon()->is_writeable()) {
+    dout(20) << "osdmon is not writeable" << dendl;
     osdmon()->wait_for_writeable_ctx(new CMonGoRecovery(this));
+    return;
   }
   osdmon()->trigger_recovery_stretch_mode();
 }
@@ -6771,10 +6776,14 @@ void Monitor::maybe_go_degraded_stretch_mode()
 						   &matched_down_mons);
   if (dead) {
     if (!osdmon()->is_writeable()) {
+      dout(20) << "osdmon is not writeable" << dendl;
       osdmon()->wait_for_writeable_ctx(new CMonGoDegraded(this));
+      return;
     }
     if (!monmon()->is_writeable()) {
+      dout(20) << "monmon is not writeable" << dendl;
       monmon()->wait_for_writeable_ctx(new CMonGoDegraded(this));
+      return;
     }
     trigger_degraded_stretch_mode(matched_down_mons, matched_down_buckets);
   }
@@ -6824,10 +6833,14 @@ void Monitor::trigger_healthy_stretch_mode()
   if (!is_degraded_stretch_mode()) return;
   if (!is_leader()) return;
   if (!osdmon()->is_writeable()) {
+    dout(20) << "osdmon is not writeable" << dendl;
     osdmon()->wait_for_writeable_ctx(new CMonGoHealthy(this));
+    return;
   }
   if (!monmon()->is_writeable()) {
+    dout(20) << "monmon is not writeable" << dendl;
     monmon()->wait_for_writeable_ctx(new CMonGoHealthy(this));
+    return;
   }
 
   ceph_assert(osdmon()->osdmap.recovering_stretch_mode);
-- 
2.47.3