libglusterfs: serialize init/reconfigure calls

These functions do not generally "expect" to be called more than once
in parallel, and many are likely to misbehave in that case (one case
in DHT already).  Such parallel calls have not generally happened
because there are only a few places where we call these functions, and
those have been implicitly serialized until recently.  However, recent
changes in the epoll layer change that, as does brick multiplexing.
Therefore, the serialization is now explicit at the init/reconfigure
level.

It would be sufficient to serialize calls to a particular translator's
init and reconfigure functions, but that would require per-translator
locks and a bit more complexity in maintaining/using them.  Since
there's no clear reason why we would need or want to support a higher
level of parallelism, the simpler approach of a global lock should
suffice.

Change-Id: I26296c2826e91dc00b7f0c2061bcc2964ef90c4c
BUG: 1399134
Signed-off-by: Jeff Darcy <jdarcy@redhat.com>
Reviewed-on: http://review.gluster.org/16030
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>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/libglusterfs/src/xlator.c b/libglusterfs/src/xlator.c
index 3c1cde50fa0..2edebc0aec2 100644
--- a/libglusterfs/src/xlator.c
+++ b/libglusterfs/src/xlator.c
@@ -25,6 +25,21 @@
                         xl->cbks->fn = default_##fn;	\
         } while (0)
 
+pthread_mutex_t xlator_init_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+void
+xlator_init_lock (void)
+{
+        (void) pthread_mutex_lock (&xlator_init_mutex);
+}
+
+
+void
+xlator_init_unlock (void)
+{
+        (void) pthread_mutex_unlock (&xlator_init_mutex);
+}
+
 
 static void
 fill_defaults (xlator_t *xl)
@@ -400,7 +415,9 @@ __xlator_init(xlator_t *xl)
         old_THIS = THIS;
         THIS = xl;
 
+        xlator_init_lock ();
         ret = xl->init (xl);
+        xlator_init_unlock ();
 
         THIS = old_THIS;