glusterd: cleanup of volinfo '*_count' definitionsv3.3.0qa11

earlier, sub_count was having different meaning depending on the
volume type.

now, for replica and stripe count, one can directly access the
'replica_count' or 'stripe_count' to get the corresponding
value from the volume info. 'sub_count' is preserved as is for backward
compatibility. there is a new variable 'dist_leaf_count' to get
info about how many bricks are present in one distribute sub volume.

Change-Id: I5ea1c8f9ae08f584cca63b91ba69035c7e4350ca
BUG: 3158
Reviewed-on: http://review.gluster.com/435
Reviewed-by: Krishnan Parthasarathi <kp@gluster.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>

9 files changed, 217 insertions, 150 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-brick-ops.c b/xlators/mgmt/glusterd/src/glusterd-brick-ops.c
index 655f8a96a..f488996c0 100644
--- a/xlators/mgmt/glusterd/src/glusterd-brick-ops.c
+++ b/xlators/mgmt/glusterd/src/glusterd-brick-ops.c
@@ -118,36 +118,43 @@ glusterd_handle_add_brick (rpcsvc_request_t *req)
                 goto out;
         }
 
-        if (!(ret = glusterd_volinfo_find (volname, &volinfo))) {
-                if (volinfo->type == GF_CLUSTER_TYPE_NONE)
-                        goto brick_val;
-                if (!brick_count || !volinfo->sub_count)
-                        goto brick_val;
-
-                total_bricks = volinfo->brick_count + brick_count;
-		/* If the brick count is less than sub_count then, allow add-brick only for
-		   plain replicate volume since in plain stripe brick_count becoming less than
-		   the sub_count is not allowed */
-                if (volinfo->brick_count < volinfo->sub_count &&
-                    (volinfo->type == GF_CLUSTER_TYPE_REPLICATE)) {
-                        if (total_bricks <= volinfo->sub_count)
-                                goto brick_val;
-                }
-
-                if ((brick_count % volinfo->sub_count) != 0) {
-                        snprintf(err_str, 2048, "Incorrect number of bricks"
-                                " supplied %d for type %s with count %d",
-                                brick_count, (volinfo->type == 1)? "STRIPE":
-                                "REPLICATE", volinfo->sub_count);
-                        gf_log("glusterd", GF_LOG_ERROR, "%s", err_str);
-                        ret = -1;
-                        goto out;
-                }
-        } else {
+        ret = glusterd_volinfo_find (volname, &volinfo);
+        if (ret) {
                 snprintf (err_str, sizeof (err_str), "Unable to get volinfo "
                           "for volume name %s", volname);
                 gf_log ("glusterd", GF_LOG_ERROR, "%s", err_str);
                 goto out;
+
+        }
+
+        /* If any of this is true, some thing is wrong */
+        if (!brick_count || !volinfo->sub_count) {
+                ret = -1;
+                snprintf (err_str, sizeof (err_str), "number of brick count "
+                          "for volume name %s is wrong", volname);
+                goto out;
+        }
+
+        if (volinfo->type == GF_CLUSTER_TYPE_NONE)
+                goto brick_val;
+
+        total_bricks = volinfo->brick_count + brick_count;
+        /* If the brick count is less than dist_leaf_count then, allow
+           add-brick only for plain replicate volume since in plain stripe
+           brick_count becoming less than the dist_leaf_count is not allowed */
+        if (volinfo->brick_count < volinfo->dist_leaf_count &&
+            (volinfo->type == GF_CLUSTER_TYPE_REPLICATE)) {
+                if (total_bricks <= volinfo->replica_count)
+                        goto brick_val;
+        }
+
+        if ((brick_count % volinfo->dist_leaf_count) != 0) {
+                snprintf(err_str, 2048, "Incorrect number of bricks"
+                         " supplied %d with count %d",
+                         brick_count, volinfo->dist_leaf_count);
+                gf_log("glusterd", GF_LOG_ERROR, "%s", err_str);
+                ret = -1;
+                goto out;
         }
 
 brick_val:
@@ -169,10 +176,8 @@ brick_val:
                 free_ptr = brick_list;
         }
 
-        gf_cmd_log ("Volume add-brick", "volname: %s type %s count:%d bricks:%s"
-                    ,volname, ((volinfo->type == 0)? "DEFAULT" : ((volinfo->type
-                    == 1)? "STRIPE": "REPLICATE")), brick_count, brick_list);
-
+        gf_cmd_log ("Volume add-brick", "volname: %s type %d count:%d bricks:%s"
+                    ,volname, volinfo->type, brick_count, brick_list);
 
         while ( i < brick_count) {
                 i++;
@@ -314,7 +319,7 @@ glusterd_handle_remove_brick (rpcsvc_request_t *req)
 
 	/* Do not allow remove-brick if the volume is plain stripe */
 	if ((volinfo->type == GF_CLUSTER_TYPE_STRIPE) &&
-            (volinfo->brick_count == volinfo->sub_count)) {
+            (volinfo->brick_count == volinfo->stripe_count)) {
                 snprintf (err_str, 2048, "Removing brick from a plain stripe is not allowed");
                 gf_log ("glusterd", GF_LOG_ERROR, "%s", err_str);
                 ret = -1;
@@ -324,11 +329,12 @@ glusterd_handle_remove_brick (rpcsvc_request_t *req)
 	/* Do not allow remove-brick if the bricks given is less than the replica count
 	   or stripe count */
         if ((volinfo->type != GF_CLUSTER_TYPE_NONE) &&
-            !(volinfo->brick_count <= volinfo->sub_count)) {
-                if (volinfo->sub_count && (count % volinfo->sub_count != 0)) {
+            !(volinfo->brick_count <= volinfo->dist_leaf_count)) {
+                if (volinfo->dist_leaf_count &&
+                    (count % volinfo->dist_leaf_count)) {
                         snprintf (err_str, 2048, "Remove brick incorrect"
                                   " brick count of %d for %s %d",
-                                  count, vol_type, volinfo->sub_count);
+                                  count, vol_type, volinfo->dist_leaf_count);
                         gf_log ("", GF_LOG_ERROR, "%s", err_str);
                         ret = -1;
                         goto out;
@@ -367,37 +373,38 @@ glusterd_handle_remove_brick (rpcsvc_request_t *req)
 
                 i++;
                 if ((volinfo->type == GF_CLUSTER_TYPE_NONE) ||
-                    (volinfo->brick_count <= volinfo->sub_count))
+                    (volinfo->brick_count <= volinfo->dist_leaf_count))
                         continue;
 
                 pos = 0;
                 list_for_each_entry (tmp, &volinfo->bricks, brick_list) {
 
-                        if ((!strcmp (tmp->hostname,brickinfo->hostname)) &&
-                            !strcmp (tmp->path, brickinfo->path)) {
-                                gf_log ("", GF_LOG_INFO, "Found brick");
-                                if (!sub_volume && volinfo->sub_count) {
-                                        sub_volume = (pos / volinfo->
-                                                      sub_count) + 1;
-                                        sub_volume_start = volinfo->sub_count *
-                                                           (sub_volume - 1);
-                                        sub_volume_end = (volinfo->sub_count *
-                                                          sub_volume) -1 ;
-                                } else {
-                                        if (pos < sub_volume_start ||
-                                            pos >sub_volume_end) {
-                                                ret = -1;
-                                                snprintf(err_str, 2048,"Bricks"
-                                                         " not from same subvol"
-                                                         " for %s", vol_type);
-                                                gf_log ("",GF_LOG_ERROR,
-                                                        "%s", err_str);
-                                                goto out;
-                                        }
+                        if (strcmp (tmp->hostname,brickinfo->hostname) ||
+                            strcmp (tmp->path, brickinfo->path)) {
+                                pos++;
+                                continue;
+                        }
+
+                        gf_log ("", GF_LOG_INFO, "Found brick");
+                        if (!sub_volume && (volinfo->dist_leaf_count > 1)) {
+                                sub_volume = (pos / volinfo->dist_leaf_count) + 1;
+                                sub_volume_start = (volinfo->dist_leaf_count *
+                                                    (sub_volume - 1));
+                                sub_volume_end = (volinfo->dist_leaf_count *
+                                                  sub_volume) - 1;
+                        } else {
+                                if (pos < sub_volume_start ||
+                                    pos >sub_volume_end) {
+                                        ret = -1;
+                                        snprintf(err_str, 2048,"Bricks not from"
+                                                 " same subvol for %s",
+                                                 vol_type);
+                                        gf_log ("", GF_LOG_ERROR,
+                                                "%s", err_str);
+                                        goto out;
                                 }
-                                break;
                         }
-                        pos++;
+                        break;
                 }
         }
         gf_cmd_log ("Volume remove-brick","volname: %s count:%d bricks:%s",
diff --git a/xlators/mgmt/glusterd/src/glusterd-handler.c b/xlators/mgmt/glusterd/src/glusterd-handler.c
index 2ab80c2ff..a62255c01 100644
--- a/xlators/mgmt/glusterd/src/glusterd-handler.c
+++ b/xlators/mgmt/glusterd/src/glusterd-handler.c
@@ -316,8 +316,8 @@ glusterd_add_volume_detail_to_dict (glusterd_volinfo_t *volinfo,
         if (ret)
                 goto out;
 
-        snprintf (key, 256, "volume%d.sub_count", count);
-        ret = dict_set_int32 (volumes, key, volinfo->sub_count);
+        snprintf (key, 256, "volume%d.dist_count", count);
+        ret = dict_set_int32 (volumes, key, volinfo->dist_leaf_count);
         if (ret)
                 goto out;
 
@@ -326,6 +326,11 @@ glusterd_add_volume_detail_to_dict (glusterd_volinfo_t *volinfo,
         if (ret)
                 goto out;
 
+        snprintf (key, 256, "volume%d.replica_count", count);
+        ret = dict_set_int32 (volumes, key, volinfo->replica_count);
+        if (ret)
+                goto out;
+
         snprintf (key, 256, "volume%d.transport", count);
         ret = dict_set_int32 (volumes, key, volinfo->transport_type);
         if (ret)
diff --git a/xlators/mgmt/glusterd/src/glusterd-op-sm.c b/xlators/mgmt/glusterd/src/glusterd-op-sm.c
index 84280498e..11cbeba08 100644
--- a/xlators/mgmt/glusterd/src/glusterd-op-sm.c
+++ b/xlators/mgmt/glusterd/src/glusterd-op-sm.c
@@ -2746,16 +2746,7 @@ glusterd_bricks_select_heal_volume (dict_t *dict, char **op_errstr)
                 goto out;
         }
 
-        if (volinfo->type == GF_CLUSTER_TYPE_STRIPE_REPLICATE) {
-                replica_count = volinfo->replica_count;
-
-        } else if (volinfo->type == GF_CLUSTER_TYPE_REPLICATE) {
-                replica_count = volinfo->sub_count;
-
-        } else {
-                GF_ASSERT (0);
-                goto out;
-        }
+        replica_count = volinfo->replica_count;
 
         index = 1;
         list_for_each_entry (brickinfo, &volinfo->bricks, brick_list) {
diff --git a/xlators/mgmt/glusterd/src/glusterd-store.c b/xlators/mgmt/glusterd/src/glusterd-store.c
index dab075db0..a18deceaf 100644
--- a/xlators/mgmt/glusterd/src/glusterd-store.c
+++ b/xlators/mgmt/glusterd/src/glusterd-store.c
@@ -599,6 +599,12 @@ glusterd_volume_exclude_options_write (int fd, glusterd_volinfo_t *volinfo)
         if (ret)
                 goto out;
 
+        snprintf (buf, sizeof (buf), "%d", volinfo->replica_count);
+        ret = glusterd_store_save_value (fd, GLUSTERD_STORE_KEY_VOL_REPLICA_CNT,
+                                         buf);
+        if (ret)
+                goto out;
+
         snprintf (buf, sizeof (buf), "%d", volinfo->version);
         ret = glusterd_store_save_value (fd, GLUSTERD_STORE_KEY_VOL_VERSION,
                                          buf);
@@ -1827,6 +1833,9 @@ glusterd_store_retrieve_volume (char    *volname)
                 } else if (!strncmp (key, GLUSTERD_STORE_KEY_VOL_STRIPE_CNT,
                                      strlen (GLUSTERD_STORE_KEY_VOL_STRIPE_CNT))) {
                         volinfo->stripe_count = atoi (value);
+                } else if (!strncmp (key, GLUSTERD_STORE_KEY_VOL_REPLICA_CNT,
+                                     strlen (GLUSTERD_STORE_KEY_VOL_REPLICA_CNT))) {
+                        volinfo->replica_count = atoi (value);
                 } else if (!strncmp (key, GLUSTERD_STORE_KEY_VOL_TRANSPORT,
                                      strlen (GLUSTERD_STORE_KEY_VOL_TRANSPORT))) {
                         volinfo->transport_type = atoi (value);
@@ -1883,13 +1892,32 @@ glusterd_store_retrieve_volume (char    *volname)
                 ret = glusterd_store_iter_get_next (iter, &key, &value,
                                                     &op_errno);
         }
+
+        /* backward compatibility */
+        {
+                /* would be true if type is 'GF_CLUSTER_TYPE_NONE' */
+                if (!volinfo->dist_leaf_count)
+                        volinfo->dist_leaf_count = ((!volinfo->sub_count) ? 1 :
+                                                    volinfo->sub_count);
+
+                /* would be true for all volumes in 3.1.x and 3.2.x,
+                   or if type is not 'STRIPE_REPLICATE' (in 3.3 pre-releases) */
+                if (!volinfo->stripe_count)
+                        volinfo->stripe_count = 1;
+
+                /* would be true for some pre-releases of 3.3, and all
+                   releases of 3.1.x and 3.2.x */
+                if (!volinfo->replica_count)
+                        volinfo->replica_count = (volinfo->dist_leaf_count /
+                                                  volinfo->stripe_count);
+
+                volinfo->dist_leaf_count = (volinfo->stripe_count *
+                                            volinfo->replica_count);
+        }
+
         if (op_errno != GD_STORE_EOF)
                 goto out;
 
-        if (volinfo->stripe_count)
-                volinfo->replica_count = (volinfo->sub_count /
-                                          volinfo->stripe_count);
-
         ret = glusterd_store_iter_destroy (iter);
 
         if (ret)
diff --git a/xlators/mgmt/glusterd/src/glusterd-store.h b/xlators/mgmt/glusterd/src/glusterd-store.h
index 61bda195d..f1413955b 100644
--- a/xlators/mgmt/glusterd/src/glusterd-store.h
+++ b/xlators/mgmt/glusterd/src/glusterd-store.h
@@ -50,7 +50,8 @@ typedef enum glusterd_store_ver_ac_{
 #define GLUSTERD_STORE_KEY_VOL_STATUS     "status"
 #define GLUSTERD_STORE_KEY_VOL_PORT       "port"
 #define GLUSTERD_STORE_KEY_VOL_SUB_COUNT  "sub_count"
-#define GLUSTERD_STORE_KEY_VOL_STRIPE_CNT "stripe_count"
+#define GLUSTERD_STORE_KEY_VOL_STRIPE_CNT  "stripe_count"
+#define GLUSTERD_STORE_KEY_VOL_REPLICA_CNT "replica_count"
 #define GLUSTERD_STORE_KEY_VOL_BRICK      "brick"
 #define GLUSTERD_STORE_KEY_VOL_VERSION    "version"
 #define GLUSTERD_STORE_KEY_VOL_TRANSPORT  "transport-type"
diff --git a/xlators/mgmt/glusterd/src/glusterd-utils.c b/xlators/mgmt/glusterd/src/glusterd-utils.c
index 59609971b..3681d4b95 100644
--- a/xlators/mgmt/glusterd/src/glusterd-utils.c
+++ b/xlators/mgmt/glusterd/src/glusterd-utils.c
@@ -1482,6 +1482,18 @@ glusterd_add_volume_to_dict (glusterd_volinfo_t *volinfo,
                 goto out;
 
         memset (key, 0, sizeof (key));
+        snprintf (key, sizeof (key), "volume%d.replica_count", count);
+        ret = dict_set_int32 (dict, key, volinfo->replica_count);
+        if (ret)
+                goto out;
+
+        memset (key, 0, sizeof (key));
+        snprintf (key, sizeof (key), "volume%d.dist_count", count);
+        ret = dict_set_int32 (dict, key, volinfo->dist_leaf_count);
+        if (ret)
+                goto out;
+
+        memset (key, 0, sizeof (key));
         snprintf (key, sizeof (key), "volume%d.ckusm", count);
         ret = dict_set_int64 (dict, key, volinfo->cksum);
         if (ret)
@@ -1958,11 +1970,27 @@ glusterd_import_volinfo (dict_t *vols, int count,
         memset (key, 0, sizeof (key));
         snprintf (key, sizeof (key), "volume%d.stripe_count", count);
         ret = dict_get_int32 (vols, key, &new_volinfo->stripe_count);
-        if (!ret) {
-                if (new_volinfo->stripe_count)
-                        new_volinfo->replica_count = (new_volinfo->sub_count /
-                                                      new_volinfo->stripe_count);
-        }
+        if (ret)
+                gf_log (THIS->name, GF_LOG_INFO,
+                        "peer is possibly old version");
+
+        /* not having a 'replica_count' key is not a error
+           (as peer may be of old version) */
+        memset (key, 0, sizeof (key));
+        snprintf (key, sizeof (key), "volume%d.replica_count", count);
+        ret = dict_get_int32 (vols, key, &new_volinfo->replica_count);
+        if (ret)
+                gf_log (THIS->name, GF_LOG_INFO,
+                        "peer is possibly old version");
+
+        /* not having a 'dist_count' key is not a error
+           (as peer may be of old version) */
+        memset (key, 0, sizeof (key));
+        snprintf (key, sizeof (key), "volume%d.dist_count", count);
+        ret = dict_get_int32 (vols, key, &new_volinfo->dist_leaf_count);
+        if (ret)
+                gf_log (THIS->name, GF_LOG_INFO,
+                        "peer is possibly old version");
 
         memset (key, 0, sizeof (key));
         snprintf (key, sizeof (key), "volume%d.ckusm", count);
diff --git a/xlators/mgmt/glusterd/src/glusterd-volgen.c b/xlators/mgmt/glusterd/src/glusterd-volgen.c
index 77478f365..e1934493a 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volgen.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volgen.c
@@ -1869,17 +1869,17 @@ volgen_graph_build_clients (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
         if (volinfo->brick_count == 0) {
                 gf_log ("", GF_LOG_ERROR,
                         "volume inconsistency: brick count is 0");
-
                 goto out;
         }
-        if (volinfo->sub_count && volinfo->sub_count < volinfo->brick_count &&
-            volinfo->brick_count % volinfo->sub_count != 0) {
+
+        if ((volinfo->dist_leaf_count < volinfo->brick_count) &&
+            ((volinfo->brick_count % volinfo->dist_leaf_count) != 0)) {
                 gf_log ("", GF_LOG_ERROR,
                         "volume inconsistency: "
                         "total number of bricks (%d) is not divisible with "
                         "number of bricks per cluster (%d) in a multi-cluster "
                         "setup",
-                        volinfo->brick_count, volinfo->sub_count);
+                        volinfo->brick_count, volinfo->dist_leaf_count);
                 goto out;
         }
 
@@ -1941,7 +1941,7 @@ volgen_graph_build_clusters (volgen_graph_t *graph,
         txl = first_of (graph);
         for (trav = txl; --child_count; trav = trav->next);
         for (;; trav = trav->prev) {
-                if (i % sub_count == 0) {
+                if ((i % sub_count) == 0) {
                         xl = volgen_graph_add_nolink (graph, xl_type,
                                                       xl_namefmt, volname, j);
                         if (!xl) {
@@ -2105,62 +2105,62 @@ volume_volgen_graph_build_clusters (volgen_graph_t *graph,
         int                     dist_count          = 0;
         int                     ret                 = -1;
 
-        if (volinfo->sub_count > 1) {
-                switch (volinfo->type) {
-                case GF_CLUSTER_TYPE_REPLICATE:
-                        clusters = volgen_graph_build_clusters (graph, volinfo,
-                                                           replicate_args[0],
-                                                           replicate_args[1],
-                                                           volinfo->brick_count,
-                                                           volinfo->sub_count);
-                        if (clusters < 0)
-                                goto out;
-                        break;
-                case GF_CLUSTER_TYPE_STRIPE:
-                        clusters = volgen_graph_build_clusters (graph, volinfo,
-                                                           stripe_args[0],
-                                                           stripe_args[1],
-                                                           volinfo->brick_count,
-                                                           volinfo->sub_count);
-                        if (clusters < 0)
-                                goto out;
-                        break;
-                case GF_CLUSTER_TYPE_STRIPE_REPLICATE:
-                        /* Replicate after the clients, then stripe */
-                        if (volinfo->replica_count == 0)
-                                return -1;
-                        clusters = volgen_graph_build_clusters (graph, volinfo,
-                                                           replicate_args[0],
-                                                           replicate_args[1],
-                                                           volinfo->brick_count,
-                                                           volinfo->replica_count);
-                        if (clusters < 0)
-                                goto out;
+        if (!volinfo->dist_leaf_count)
+                goto out;
 
-                        rclusters = volinfo->brick_count/volinfo->replica_count;
-                        GF_ASSERT (rclusters == clusters);
-                        clusters = volgen_graph_build_clusters (graph, volinfo,
-                                                           stripe_args[0],
-                                                           stripe_args[1],
-                                                           rclusters,
-                                                           volinfo->stripe_count);
-                        if (clusters < 0)
-                                goto out;
-                        break;
-                default:
-                        gf_log ("", GF_LOG_ERROR, "volume inconsistency: "
-                                "unrecognized clustering type");
+        if (volinfo->dist_leaf_count == 1)
+                goto build_distribute;
+
+        /* All other cases, it will have one or the other cluster type */
+        switch (volinfo->type) {
+        case GF_CLUSTER_TYPE_REPLICATE:
+                clusters = volgen_graph_build_clusters (graph, volinfo,
+                                                        replicate_args[0],
+                                                        replicate_args[1],
+                                                        volinfo->brick_count,
+                                                        volinfo->replica_count);
+                if (clusters < 0)
+                        goto out;
+                break;
+        case GF_CLUSTER_TYPE_STRIPE:
+                clusters = volgen_graph_build_clusters (graph, volinfo,
+                                                        stripe_args[0],
+                                                        stripe_args[1],
+                                                        volinfo->brick_count,
+                                                        volinfo->stripe_count);
+                if (clusters < 0)
+                        goto out;
+                break;
+        case GF_CLUSTER_TYPE_STRIPE_REPLICATE:
+                /* Replicate after the clients, then stripe */
+                if (volinfo->replica_count == 0)
+                        goto out;
+                clusters = volgen_graph_build_clusters (graph, volinfo,
+                                                        replicate_args[0],
+                                                        replicate_args[1],
+                                                        volinfo->brick_count,
+                                                        volinfo->replica_count);
+                if (clusters < 0)
                         goto out;
-                }
-        }
 
-        if (volinfo->sub_count) {
-                dist_count = volinfo->brick_count / volinfo->sub_count;
-                GF_ASSERT (dist_count == clusters);
-        } else {
-                dist_count = volinfo->brick_count;
+                rclusters = volinfo->brick_count / volinfo->replica_count;
+                GF_ASSERT (rclusters == clusters);
+                clusters = volgen_graph_build_clusters (graph, volinfo,
+                                                        stripe_args[0],
+                                                        stripe_args[1],
+                                                        rclusters,
+                                                        volinfo->stripe_count);
+                if (clusters < 0)
+                        goto out;
+                break;
+        default:
+                gf_log ("", GF_LOG_ERROR, "volume inconsistency: "
+                        "unrecognized clustering type");
+                goto out;
         }
 
+build_distribute:
+        dist_count = volinfo->brick_count / volinfo->dist_leaf_count;
         if (dist_count > 1) {
                 ret = volgen_graph_build_dht_cluster (graph, volinfo,
                                                       dist_count);
@@ -2460,12 +2460,7 @@ build_shd_graph (volgen_graph_t *graph, dict_t *mod_dict)
                 if (voliter->status != GLUSTERD_STATUS_STARTED)
                         continue;
 
-                if (voliter->type == GF_CLUSTER_TYPE_REPLICATE)
-                        replica_count = voliter->sub_count;
-                else if (voliter->type == GF_CLUSTER_TYPE_STRIPE_REPLICATE)
-                        replica_count = voliter->replica_count;
-                else
-                        continue;
+                replica_count = voliter->replica_count;
 
                 valid_config = _gf_true;
 
diff --git a/xlators/mgmt/glusterd/src/glusterd-volume-ops.c b/xlators/mgmt/glusterd/src/glusterd-volume-ops.c
index 39cc02c8e..816ef9b18 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volume-ops.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volume-ops.c
@@ -921,7 +921,6 @@ glusterd_op_create_volume (dict_t *dict, char **op_errstr)
         char                 *brick_list = NULL;
         char                 *free_ptr   = NULL;
         char                 *saveptr    = NULL;
-        int32_t               sub_count  = 0;
         char                 *trans_type = NULL;
         char                 *str        = NULL;
 
@@ -974,14 +973,19 @@ glusterd_op_create_volume (dict_t *dict, char **op_errstr)
                 goto out;
         }
 
+        /* replica-count 1 means, no replication, file is in one brick only */
+        volinfo->replica_count = 1;
+        /* stripe-count 1 means, no striping, file is present as a whole */
+        volinfo->stripe_count = 1;
+
         if (GF_CLUSTER_TYPE_REPLICATE == volinfo->type) {
                 ret = dict_get_int32 (dict, "replica-count",
-                                      &sub_count);
+                                      &volinfo->replica_count);
                 if (ret)
                         goto out;
         } else if (GF_CLUSTER_TYPE_STRIPE == volinfo->type) {
                 ret = dict_get_int32 (dict, "stripe-count",
-                                      &sub_count);
+                                      &volinfo->stripe_count);
                 if (ret)
                         goto out;
         } else if (GF_CLUSTER_TYPE_STRIPE_REPLICATE == volinfo->type) {
@@ -993,10 +997,18 @@ glusterd_op_create_volume (dict_t *dict, char **op_errstr)
                                       &volinfo->replica_count);
                 if (ret)
                         goto out;
-
-                sub_count = volinfo->stripe_count * volinfo->replica_count;
         }
 
+        /* dist-leaf-count is the count of brick nodes for a given
+           subvolume of distribute */
+        volinfo->dist_leaf_count = (volinfo->stripe_count *
+                                    volinfo->replica_count);
+
+        /* Keep sub-count same as earlier, for the sake of backward
+           compatibility */
+        if (volinfo->dist_leaf_count > 1)
+                volinfo->sub_count = volinfo->dist_leaf_count;
+
         ret = dict_get_str (dict, "transport", &trans_type);
         if (ret) {
                 gf_log ("", GF_LOG_ERROR, "Unable to get transport");
@@ -1025,8 +1037,6 @@ glusterd_op_create_volume (dict_t *dict, char **op_errstr)
                 volinfo->nfs_transport_type = GF_DEFAULT_NFS_TRANSPORT;
         }
 
-        volinfo->sub_count = sub_count;
-
         if (bricks) {
                 brick_list = gf_strdup (bricks);
                 free_ptr = brick_list;
diff --git a/xlators/mgmt/glusterd/src/glusterd.h b/xlators/mgmt/glusterd/src/glusterd.h
index b49e7d675..f5a10189b 100644
--- a/xlators/mgmt/glusterd/src/glusterd.h
+++ b/xlators/mgmt/glusterd/src/glusterd.h
@@ -197,9 +197,11 @@ struct glusterd_volinfo_ {
         struct list_head        vol_list;
         struct list_head        bricks;
         glusterd_volume_status  status;
-        int                     sub_count;
+        int                     sub_count;  /* backward compatibility */
         int                     stripe_count;
         int                     replica_count;
+        int                     dist_leaf_count; /* Number of bricks in one
+                                                    distribute subvolume */
         int                     port;
         glusterd_store_handle_t *shandle;
         glusterd_store_handle_t *rb_shandle;