performance/io-threads: Exit all threads on PARENT_DOWN

Problem:
When glfs_fini() is called on a volume where client.io-threads is enabled,
fini() will free up iothread xl's private structure but there would be some
threads that are sleeping which would wakeup after the timedwait completes
leading to accessing already free'd memory.

Fix:
As part of parent-down, exit all sleeping threads.

 >BUG: 1381830
 >Change-Id: I0bb8d90241112c355fb22ee3fbfd7307f475b339
 >Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
 >Reviewed-on: http://review.gluster.org/15620
 >Smoke: Gluster Build System <jenkins@build.gluster.org>
 >CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
 >NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
 >Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
 >(cherry picked from commit d7a5ca16911caca03cec1112d4be56a9cda2ee30)

Change-Id: I450e5db84c83fae3237aaa7915c08cd3ee9bde2c
BUG: 1387894
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/15701
Smoke: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>

2 files changed, 40 insertions, 17 deletions

diff --git a/xlators/performance/io-threads/src/io-threads.c b/xlators/performance/io-threads/src/io-threads.c
index c6a18fdc0b3..a30de1572b9 100644
--- a/xlators/performance/io-threads/src/io-threads.c
+++ b/xlators/performance/io-threads/src/io-threads.c
@@ -165,8 +165,7 @@ iot_worker (void *data)
         struct timespec   sleep_till = {0, };
         int               ret = 0;
         int               pri = -1;
-        char              timeout = 0;
-        char              bye = 0;
+        gf_boolean_t      bye = _gf_false;
 
         conf = data;
         this = conf->this;
@@ -182,6 +181,11 @@ iot_worker (void *data)
                                 pri = -1;
                         }
                         while (conf->queue_size == 0) {
+                                if (conf->down) {
+                                        bye = _gf_true;/*Avoid sleep*/
+                                        break;
+                                }
+
                                 conf->sleep_count++;
 
                                 ret = pthread_cond_timedwait (&conf->cond,
@@ -189,42 +193,39 @@ iot_worker (void *data)
                                                               &sleep_till);
                                 conf->sleep_count--;
 
-                                if (ret == ETIMEDOUT) {
-                                        timeout = 1;
+                                if (conf->down || ret == ETIMEDOUT) {
+                                        bye = _gf_true;
                                         break;
                                 }
                         }
 
-                        if (timeout) {
-                                if (conf->curr_count > IOT_MIN_THREADS) {
+                        if (bye) {
+                                if (conf->down || conf->curr_count > IOT_MIN_THREADS) {
                                         conf->curr_count--;
-                                        bye = 1;
+                                        if (conf->curr_count == 0)
+                                           pthread_cond_broadcast (&conf->cond);
                                         gf_msg_debug (conf->this->name, 0,
-                                                      "timeout, terminated. conf->curr_count=%d",
+                                                      "terminated. "
+                                                      "conf->curr_count=%d",
                                                       conf->curr_count);
                                 } else {
-                                        timeout = 0;
+                                        bye = _gf_false;
                                 }
                         }
 
-                        stub = __iot_dequeue (conf, &pri);
+                        if (!bye)
+                                stub = __iot_dequeue (conf, &pri);
                 }
                 pthread_mutex_unlock (&conf->mutex);
 
                 if (stub) /* guard against spurious wakeups */
                         call_resume (stub);
+                stub = NULL;
 
                 if (bye)
                         break;
         }
 
-        if (pri != -1) {
-                pthread_mutex_lock (&conf->mutex);
-                {
-                        conf->ac_iot_count[pri]--;
-                }
-                pthread_mutex_unlock (&conf->mutex);
-        }
         return NULL;
 }
 
@@ -1045,6 +1046,27 @@ out:
 	return ret;
 }
 
+int
+notify (xlator_t *this, int32_t event, void *data, ...)
+{
+        iot_conf_t *conf = this->private;
+
+        if (GF_EVENT_PARENT_DOWN == event) {
+                pthread_mutex_lock (&conf->mutex);
+                {
+                        conf->down = _gf_true;
+                        /*Let all the threads know that xl is going down*/
+                        pthread_cond_broadcast (&conf->cond);
+                        while (conf->curr_count)/*Wait for threads to exit*/
+                                pthread_cond_wait (&conf->cond, &conf->mutex);
+                }
+                pthread_mutex_unlock (&conf->mutex);
+        }
+
+        default_notify (this, event, data);
+
+        return 0;
+}
 
 void
 fini (xlator_t *this)
diff --git a/xlators/performance/io-threads/src/io-threads.h b/xlators/performance/io-threads/src/io-threads.h
index 7c4ce7849b4..ae548cbcd44 100644
--- a/xlators/performance/io-threads/src/io-threads.h
+++ b/xlators/performance/io-threads/src/io-threads.h
@@ -81,6 +81,7 @@ struct iot_conf {
 
         xlator_t            *this;
         size_t               stack_size;
+        gf_boolean_t         down; /*PARENT_DOWN event is notified*/
 };
 
 typedef struct iot_conf iot_conf_t;