From 8c81776212d0aa44f5ae20635079bd6ce76d16ac Mon Sep 17 00:00:00 2001

From: Daan De Meyer <daan.j.demeyer@gmail.com>

Date: Tue, 19 Oct 2021 10:45:48 +0100

Subject: [PATCH] core: Delay start rate limit check when starting a unit

Doing start rate limit checks before doing condition checks made

condition check failures count towards the start rate limit which

broke existing assumptions (see #21025). Run the rate limit checks

after the condition checks again to restore the previous behaviour.

(cherry picked from commit ce2146f5256659c7fb53a7d5b9dc551252e27e7e)

Related: #2065322

---

 src/core/unit.c | 14 +++++++-------

 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/core/unit.c b/src/core/unit.c

index 4fd9af87b7..b825e2418c 100644

--- a/src/core/unit.c

+++ b/src/core/unit.c

@@ -1729,13 +1729,6 @@ int unit_start(Unit *u) {

         assert(u);

-        /* Check our ability to start early so that failure conditions don't cause us to enter a busy loop. */

-        if (UNIT_VTABLE(u)->can_start) {

-                r = UNIT_VTABLE(u)->can_start(u);

-                if (r < 0)

-                        return r;

-        }

-

         /* If this is already started, then this will succeed. Note that this will even succeed if this unit

          * is not startable by the user. This is relied on to detect when we need to wait for units and when

          * waiting is finished. */

@@ -1790,6 +1783,13 @@ int unit_start(Unit *u) {

                 return unit_start(following);

         }

+        /* Check start rate limiting early so that failure conditions don't cause us to enter a busy loop. */

+        if (UNIT_VTABLE(u)->can_start) {

+                r = UNIT_VTABLE(u)->can_start(u);

+                if (r < 0)

+                        return r;

+        }

+

         /* If it is stopped, but we cannot start it, then fail */

         if (!UNIT_VTABLE(u)->start)

                 return -EBADR;