glusterd: make volinfo a refcnt'ed object.

        Backport of http://review.gluster.org/6521

Add glusterd_volinfo_remove(..) which removes @volinfo from the list
of volumes in the cluster and performs an unref on @volinfo

Change-Id: I5f546ca58f61bc334ab1bab4c51c4a21e1f66161
BUG: 1038051
Signed-off-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-on: http://review.gluster.org/6569
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

6 files changed, 55 insertions, 6 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-store.c b/xlators/mgmt/glusterd/src/glusterd-store.c
index 2ba2548d2..3a4b09009 100644
--- a/xlators/mgmt/glusterd/src/glusterd-store.c
+++ b/xlators/mgmt/glusterd/src/glusterd-store.c
@@ -166,7 +166,7 @@ out:
         if (brickinfo)
                 glusterd_brickinfo_delete (brickinfo);
         if (volinfo)
-                glusterd_volinfo_delete (volinfo);
+                glusterd_volinfo_unref (volinfo);
 
         return ret;
 }
diff --git a/xlators/mgmt/glusterd/src/glusterd-utils.c b/xlators/mgmt/glusterd/src/glusterd-utils.c
index bdfa8eebc..9a4072ce8 100644
--- a/xlators/mgmt/glusterd/src/glusterd-utils.c
+++ b/xlators/mgmt/glusterd/src/glusterd-utils.c
@@ -445,6 +445,37 @@ glusterd_check_volume_exists (char *volname)
         return _gf_true;
 }
 
+glusterd_volinfo_t *
+glusterd_volinfo_unref (glusterd_volinfo_t *volinfo)
+{
+        int refcnt = -1;
+
+        pthread_mutex_lock (&volinfo->reflock);
+        {
+                refcnt = --volinfo->refcnt;
+        }
+        pthread_mutex_unlock (&volinfo->reflock);
+
+        if (!refcnt) {
+                glusterd_volinfo_delete (volinfo);
+                return NULL;
+        }
+
+        return volinfo;
+}
+
+glusterd_volinfo_t *
+glusterd_volinfo_ref (glusterd_volinfo_t *volinfo)
+{
+        pthread_mutex_lock (&volinfo->reflock);
+        {
+                ++volinfo->refcnt;
+        }
+        pthread_mutex_unlock (&volinfo->reflock);
+
+        return volinfo;
+}
+
 int32_t
 glusterd_volinfo_new (glusterd_volinfo_t **volinfo)
 {
@@ -478,7 +509,8 @@ glusterd_volinfo_new (glusterd_volinfo_t **volinfo)
 
         new_volinfo->xl = THIS;
 
-        *volinfo = new_volinfo;
+        pthread_mutex_init (&new_volinfo->reflock, NULL);
+        *volinfo = glusterd_volinfo_ref (new_volinfo);
 
         ret = 0;
 
@@ -571,6 +603,14 @@ out:
         return ret;
 }
 
+int
+glusterd_volinfo_remove (glusterd_volinfo_t *volinfo)
+{
+        list_del_init (&volinfo->vol_list);
+        glusterd_volinfo_unref (volinfo);
+        return 0;
+}
+
 int32_t
 glusterd_volinfo_delete (glusterd_volinfo_t *volinfo)
 {
@@ -595,6 +635,7 @@ glusterd_volinfo_delete (glusterd_volinfo_t *volinfo)
 
         glusterd_auth_cleanup (volinfo);
 
+        pthread_mutex_destroy (&volinfo->reflock);
         GF_FREE (volinfo);
         ret = 0;
 
@@ -3404,7 +3445,7 @@ glusterd_delete_stale_volume (glusterd_volinfo_t *stale_volinfo,
                 (void) gf_store_handle_destroy (stale_volinfo->shandle);
                 stale_volinfo->shandle = NULL;
         }
-        (void) glusterd_volinfo_delete (stale_volinfo);
+        (void) glusterd_volinfo_remove (stale_volinfo);
         return 0;
 }
 
@@ -6128,7 +6169,7 @@ glusterd_delete_volume (glusterd_volinfo_t *volinfo)
         if (ret)
                 goto out;
 
-        ret = glusterd_volinfo_delete (volinfo);
+        glusterd_volinfo_remove (volinfo);
 out:
         gf_log (THIS->name, GF_LOG_DEBUG, "returning %d", ret);
         return ret;
diff --git a/xlators/mgmt/glusterd/src/glusterd-utils.h b/xlators/mgmt/glusterd/src/glusterd-utils.h
index fd3f57729..ec5155918 100644
--- a/xlators/mgmt/glusterd/src/glusterd-utils.h
+++ b/xlators/mgmt/glusterd/src/glusterd-utils.h
@@ -137,6 +137,12 @@ glusterd_volume_stop_glusterfs (glusterd_volinfo_t  *volinfo,
                                 glusterd_brickinfo_t   *brickinfo,
                                 gf_boolean_t del_brick);
 
+glusterd_volinfo_t *
+glusterd_volinfo_ref (glusterd_volinfo_t *volinfo);
+
+glusterd_volinfo_t *
+glusterd_volinfo_unref (glusterd_volinfo_t *volinfo);
+
 int32_t
 glusterd_volinfo_delete (glusterd_volinfo_t *volinfo);
 
diff --git a/xlators/mgmt/glusterd/src/glusterd-volgen.c b/xlators/mgmt/glusterd/src/glusterd-volgen.c
index dcff8c305..0a6746349 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volgen.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volgen.c
@@ -3184,7 +3184,7 @@ out:
         if (brickinfo)
                 glusterd_brickinfo_delete (brickinfo);
         if (volinfo)
-                glusterd_volinfo_delete (volinfo);
+                glusterd_volinfo_unref (volinfo);
         return ret;
 }
 
diff --git a/xlators/mgmt/glusterd/src/glusterd-volume-ops.c b/xlators/mgmt/glusterd/src/glusterd-volume-ops.c
index 41555230e..df2562ba6 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volume-ops.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volume-ops.c
@@ -1696,7 +1696,7 @@ glusterd_op_create_volume (dict_t *dict, char **op_errstr)
 out:
         GF_FREE(free_ptr);
         if (!vol_added && volinfo)
-                glusterd_volinfo_delete (volinfo);
+                glusterd_volinfo_unref (volinfo);
         return ret;
 }
 
diff --git a/xlators/mgmt/glusterd/src/glusterd.h b/xlators/mgmt/glusterd/src/glusterd.h
index e1e9e591f..adef55128 100644
--- a/xlators/mgmt/glusterd/src/glusterd.h
+++ b/xlators/mgmt/glusterd/src/glusterd.h
@@ -318,6 +318,8 @@ struct glusterd_volinfo_ {
 
         int                       op_version;
         int                       client_op_version;
+        pthread_mutex_t           reflock;
+        int                       refcnt;
 };
 
 typedef enum gd_node_type_ {