From: Martin Wilck <mwilck@xxxxxxxx>
If need_to_delay_reconfig() returned true, the logic introduced
by 250708c ("multipathd: improve delayed reconfigure") and
4b104e6 ("multipathd: pass in the type of reconfigure") could cause
child() to run in a tight loop, switching back and forth between
DAEMON_CONFIGURE and DAEMON_IDLE states without actually calling
reconfigure().
Move the logic to postpone reconfigure() calls from __post_config_state()
into child(), entirely, to avoid this situation. This means that child()
needs to poll for reconfigure_pending besides running_state changes.
Fixes: 250708c ("multipathd: improve delayed reconfigure")
Fixes: 4b104e6 ("multipathd: pass in the type of reconfigure")
Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
---
multipathd/main.c | 48 +++++++++++++++++++----------------------------
1 file changed, 19 insertions(+), 29 deletions(-)
diff --git a/multipathd/main.c b/multipathd/main.c
index 7ecf3bd..d033a9a 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -288,38 +288,12 @@ enum daemon_status wait_for_state_change_if(enum daemon_status oldstate,
/* Don't access this variable without holding config_lock */
static enum force_reload_types reconfigure_pending = FORCE_RELOAD_NONE;
-static void enable_delayed_reconfig(void)
-{
- pthread_mutex_lock(&config_lock);
- __delayed_reconfig = true;
- pthread_mutex_unlock(&config_lock);
-}
-
/* must be called with config_lock held */
static void __post_config_state(enum daemon_status state)
{
if (state != running_state && running_state != DAEMON_SHUTDOWN) {
enum daemon_status old_state = running_state;
- /*
- * Handle a pending reconfigure request.
- * DAEMON_IDLE is set from child() after reconfigure(),
- * or from checkerloop() after completing checkers.
- * In either case, child() will see DAEMON_CONFIGURE
- * again and start another reconfigure cycle.
- */
- if (reconfigure_pending != FORCE_RELOAD_NONE &&
- state == DAEMON_IDLE &&
- (old_state == DAEMON_CONFIGURE ||
- old_state == DAEMON_RUNNING)) {
- /*
- * notify systemd of transient idle state, lest systemd
- * thinks the reload lasts forever.
- */
- do_sd_notify(old_state, DAEMON_IDLE);
- old_state = DAEMON_IDLE;
- state = DAEMON_CONFIGURE;
- }
running_state = state;
pthread_cond_broadcast(&config_cond);
do_sd_notify(old_state, state);
@@ -3390,8 +3364,21 @@ child (__attribute__((unused)) void *param)
pthread_cleanup_push(config_cleanup, NULL);
pthread_mutex_lock(&config_lock);
while (running_state != DAEMON_CONFIGURE &&
- running_state != DAEMON_SHUTDOWN)
+ running_state != DAEMON_SHUTDOWN &&
+ /*
+ * Check if another reconfigure request was scheduled
+ * while we last ran reconfigure().
+ * We have to test __delayed_reconfig here
+ * to avoid a busy loop
+ */
+ (reconfigure_pending == FORCE_RELOAD_NONE
+ || __delayed_reconfig))
pthread_cond_wait(&config_cond, &config_lock);
+
+ if (running_state != DAEMON_CONFIGURE &&
+ running_state != DAEMON_SHUTDOWN)
+ /* This sets running_state to DAEMON_CONFIGURE */
+ __post_config_state(DAEMON_CONFIGURE);
state = running_state;
pthread_cleanup_pop(1);
if (state == DAEMON_SHUTDOWN)
@@ -3412,8 +3399,11 @@ child (__attribute__((unused)) void *param)
pthread_mutex_unlock(&config_lock);
rc = reconfigure(vecs, reload_type);
- } else
- enable_delayed_reconfig();
+ } else {
+ pthread_mutex_lock(&config_lock);
+ __delayed_reconfig = true;
+ pthread_mutex_unlock(&config_lock);
+ }
lock_cleanup_pop(vecs->lock);
if (!rc)
post_config_state(DAEMON_IDLE);
--
2.35.1
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://listman.redhat.com/mailman/listinfo/dm-devel
