glusterd: Use blocking quotad start only on quota enable

Having quotad always being using the blocking runner variant is
problematic. In some cases where quotad was started from the epoll
thread, it lead to a deadlock which lead to glusterd becoming
unresponsive.

This patch makes the default quotad_start function use the non-blocking
runner_nowait variant. The blocking start is used only when quotad is
started on quota enable command.

Change-Id: Ib27042748d69ea28e68badcfaddf61589aae4eba
BUG: 1109872
Signed-off-by: Kaushal M <kaushal@redhat.com>
Reviewed-on: http://review.gluster.org/8082
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Tested-by: Krishnan Parthasarathi <kparthas@redhat.com>

3 files changed, 28 insertions, 1 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-quota.c b/xlators/mgmt/glusterd/src/glusterd-quota.c
index 3ed0196c15a..3e29a9601bc 100644
--- a/xlators/mgmt/glusterd/src/glusterd-quota.c
+++ b/xlators/mgmt/glusterd/src/glusterd-quota.c
@@ -989,7 +989,8 @@ glusterd_quotad_op (int opcode)
                         if (glusterd_all_volumes_with_quota_stopped ())
                                 ret = glusterd_quotad_stop ();
                         else
-                                ret = glusterd_check_generate_start_quotad ();
+                                ret = glusterd_check_generate_start_quotad_wait
+                                        ();
                         break;
 
                 default:
diff --git a/xlators/mgmt/glusterd/src/glusterd-utils.c b/xlators/mgmt/glusterd/src/glusterd-utils.c
index 66eb9408a6b..9c6414905c3 100644
--- a/xlators/mgmt/glusterd/src/glusterd-utils.c
+++ b/xlators/mgmt/glusterd/src/glusterd-utils.c
@@ -6037,6 +6037,12 @@ glusterd_shd_start ()
 int
 glusterd_quotad_start ()
 {
+        return glusterd_nodesvc_start ("quotad", _gf_false);
+}
+
+int
+glusterd_quotad_start_wait ()
+{
         return glusterd_nodesvc_start ("quotad", _gf_true);
 }
 
@@ -6416,6 +6422,20 @@ glusterd_check_generate_start_quotad ()
         return ret;
 }
 
+/* Blocking start variant of glusterd_check_generate_start_quotad */
+int
+glusterd_check_generate_start_quotad_wait ()
+{
+        int ret = 0;
+
+        ret = glusterd_check_generate_start_service
+                (glusterd_create_quotad_volfile, glusterd_quotad_stop,
+                 glusterd_quotad_start_wait);
+        if (ret == -EINVAL)
+                ret = 0;
+        return ret;
+}
+
 int
 glusterd_nodesvcs_batch_op (glusterd_volinfo_t *volinfo, int (*nfs_op) (),
                             int (*shd_op) (), int (*qd_op) ())
diff --git a/xlators/mgmt/glusterd/src/glusterd-utils.h b/xlators/mgmt/glusterd/src/glusterd-utils.h
index aae91cdff8d..320bc20cdd2 100644
--- a/xlators/mgmt/glusterd/src/glusterd-utils.h
+++ b/xlators/mgmt/glusterd/src/glusterd-utils.h
@@ -223,6 +223,9 @@ int32_t
 glusterd_quotad_start ();
 
 int32_t
+glusterd_quotad_start_wait ();
+
+int32_t
 glusterd_quotad_stop ();
 
 void
@@ -268,6 +271,9 @@ int
 glusterd_check_generate_start_quotad (void);
 
 int
+glusterd_check_generate_start_quotad_wait (void);
+
+int
 glusterd_nodesvcs_handle_graph_change (glusterd_volinfo_t *volinfo);
 
 int