rebalance/glusterd: Refactor rebalance volfile

performance xlator loaded in rebalance xlators are dummy
translators, since all fops are starting with dht level.

Removing the performance xlators from rebalance volfile
will help to minimize the chance for a graph switch.

The new rebalance xlators will look like->>>

                        (io-stats)
                            ||
                            ||
                            ||
                       (----DHT----)
                      //          \\
                     //            \\
                    //              \\
              (replica-1)  ...   (replica-n)
              //      \\          //      \\
             //        \\        //        \\
            //          \\      //          \\
         client       client  client       client

Back port of :
>Change-Id: I3808e3b48fd0cb3e60ef386b8ac9fd994e2831e3
>BUG: 1240621
>Signed-off-by: Mohammed Rafi KC <rkavunga@redhat.com>
>Reviewed-on: http://review.gluster.org/11565
>Tested-by: NetBSD Build System <jenkins@build.gluster.org>
>Tested-by: Gluster Build System <jenkins@build.gluster.com>
>Reviewed-by: Dan Lambright <dlambrig@redhat.com>
>Reviewed-by: Atin Mukherjee <amukherj@redhat.com>

(cherry picked from commit 16bd894480b34e20950af795dc1ebb66d942541a)


Change-Id: I967754fd69629e983ff355e1f60eb91bbaa96b9a
BUG: 1252727
Signed-off-by: Mohammed Rafi KC <rkavunga@redhat.com>
Reviewed-on: http://review.gluster.org/11889
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: N Balachandran <nbalacha@redhat.com>
Reviewed-by: Atin Mukherjee <amukherj@redhat.com>

1 files changed, 74 insertions, 24 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-volgen.c b/xlators/mgmt/glusterd/src/glusterd-volgen.c
index 8f3e912fdab..a08d8845c8b 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volgen.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volgen.c
@@ -3527,7 +3527,6 @@ client_graph_builder (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
         gf_boolean_t     var           = _gf_false;
         gf_boolean_t     ob            = _gf_false;
         gf_boolean_t     uss_enabled   = _gf_false;
-        gf_boolean_t     rebal_volfile = _gf_false;
         xlator_t        *this          = THIS;
 
         GF_ASSERT (this);
@@ -3745,19 +3744,12 @@ client_graph_builder (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
         if (uss_enabled == -1)
                 goto out;
         if (uss_enabled && !volinfo->is_snap_volume) {
-                rebal_volfile = dict_get_str_boolean (set_dict,
-                                                   "rebalance-volfile-creation",
-                                                   _gf_false);
-                if (rebal_volfile == -1)
-                        goto out;
 
-                if (!rebal_volfile) {
-                        ret = volgen_graph_build_snapview_client
-                                                   (graph, volinfo,
-                                                    volname, set_dict);
-                        if (ret == -1)
-                                goto out;
-                }
+                ret = volgen_graph_build_snapview_client
+                                           (graph, volinfo,
+                                            volname, set_dict);
+                if (ret == -1)
+                        goto out;
         }
 
         ret = dict_get_str_boolean (set_dict, "ganesha.enable", _gf_false);
@@ -4205,6 +4197,73 @@ out:
 }
 
 static int
+build_rebalance_volfile (glusterd_volinfo_t *volinfo, char *filepath,
+                         dict_t *mod_dict)
+{
+        volgen_graph_t          graph           = {0,};
+        xlator_t                *xl             = NULL;
+        int                     ret             = -1;
+        xlator_t                *this           = NULL;
+        dict_t                  *set_dict       = NULL;
+
+        this = THIS;
+
+        if (volinfo->brick_count <= volinfo->dist_leaf_count) {
+                /*
+                 * Volume is not a distribute volume or
+                 * contains only 1 brick, no need to create
+                 * the volfiles.
+                 */
+                return 0;
+        }
+
+        if (mod_dict) {
+                set_dict = dict_copy (volinfo->dict, NULL);
+                if (!set_dict)
+                        return -1;
+                 dict_copy (mod_dict, set_dict);
+                 /* XXX dict_copy swallows errors */
+        } else {
+                set_dict = volinfo->dict;
+        }
+
+
+        ret = volgen_graph_build_clients (&graph, volinfo, set_dict, NULL);
+        if (volinfo->type == GF_CLUSTER_TYPE_TIER)
+                ret = volume_volgen_graph_build_clusters_tier
+                                        (&graph, volinfo, _gf_false);
+        else
+                ret = volume_volgen_graph_build_clusters
+                                        (&graph, volinfo, _gf_false);
+
+        xl = volgen_graph_add_as (&graph, "debug/io-stats", volinfo->volname);
+        if (!xl) {
+                ret = -1;
+                goto out;
+        }
+
+        ret = graph_set_generic_options (this, &graph, set_dict,
+                                         "rebalance-daemon");
+        if (ret)
+                goto out;
+
+        ret = volgen_graph_set_options_generic (&graph, set_dict, volinfo,
+                                                basic_option_handler);
+
+        if (!ret)
+                ret = volgen_write_volfile (&graph, filepath);
+
+out:
+        volgen_graph_free (&graph);
+
+        if (mod_dict)
+                dict_destroy (set_dict);
+
+
+        return ret;
+
+}
+static int
 build_shd_volume_graph (xlator_t *this, volgen_graph_t *graph,
                         glusterd_volinfo_t *volinfo,
                         dict_t *mod_dict, dict_t *set_dict,
@@ -4864,19 +4923,10 @@ generate_client_volfiles (glusterd_volinfo_t *volinfo,
         }
 
         /* Generate volfile for rebalance process */
-        ret = dict_set_int32 (dict, "rebalance-volfile-creation", _gf_true);
-        if (ret) {
-                gf_msg (this->name, GF_LOG_ERROR, errno,
-                        GD_MSG_DICT_SET_FAILED,
-                        "Failed to set rebalance-volfile-creation");
-                goto out;
-        }
-
         glusterd_get_rebalance_volfile (volinfo, filepath, PATH_MAX);
+        ret = build_rebalance_volfile (volinfo, filepath, dict);
+
 
-        ret = generate_single_transport_client_volfile (volinfo,
-                                                        filepath,
-                                                        dict);
         if (ret) {
                 gf_msg (this->name, GF_LOG_ERROR, 0,
                         GD_MSG_VOLFILE_CREATE_FAIL,