From 39dfe7c65d912e77e7e6e40abe146c3ebd9405fe Mon Sep 17 00:00:00 2001
From: Aravinda VK <avishwan@redhat.com>
Date: Wed, 21 Feb 2018 10:19:46 +0530
Subject: [PATCH] Add brick issue fix for Volume with single sub volume

Add brick behavior is,

- If replica count is changed, add brick appends brick to existing subvols
- If replica count is same, Creates new subvol

In case of single subvol, Replica count is not changed so new bricks are
getting added as new subvolume. This patch fixes the issue and adds the
bricks if Subvolume Type is "Distribute"

Fixes: #578
Signed-off-by: Aravinda VK <avishwan@redhat.com>
---
 glusterd2/commands/volumes/volume-expand.go | 35 ++++++++++++++++-----
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/glusterd2/commands/volumes/volume-expand.go b/glusterd2/commands/volumes/volume-expand.go
index bb1a1df3e..9dfc50b84 100644
--- a/glusterd2/commands/volumes/volume-expand.go
+++ b/glusterd2/commands/volumes/volume-expand.go
@@ -120,15 +120,30 @@ func updateVolinfoOnExpand(c transaction.TxnCtx) error {
 		return err
 	}
 
-	// Update all Subvols Replica count
-	for idx := range volinfo.Subvols {
-		volinfo.Subvols[idx].ReplicaCount = newReplicaCount
-	}
-
 	// TODO: Assumption, all subvols are same
 	// If New Replica count is different than existing then add one brick to each subvolume
-	if newReplicaCount != volinfo.Subvols[0].ReplicaCount {
-		for idx, b := range newBricks {
+	// Or if the Volume consists of only one subvolume.
+	var addNewSubvolume bool
+	switch volinfo.Subvols[0].Type {
+	case volume.SubvolDistribute:
+		addNewSubvolume = false
+	case volume.SubvolReplicate:
+		if newReplicaCount != volinfo.Subvols[0].ReplicaCount {
+			addNewSubvolume = false
+		}
+	default:
+		addNewSubvolume = true
+	}
+
+	if !addNewSubvolume {
+		idx := 0
+		for _, b := range newBricks {
+			// If number of bricks specified in add brick is more than
+			// the number of sub volumes. For example, if number of subvolumes is 2
+			// but 4 bricks specified in add brick command.
+			if idx >= len(volinfo.Subvols) {
+				idx = 0
+			}
 			volinfo.Subvols[idx].Bricks = append(volinfo.Subvols[idx].Bricks, b)
 		}
 	} else {
@@ -145,6 +160,12 @@ func updateVolinfoOnExpand(c transaction.TxnCtx) error {
 			subvolIdx = subvolIdx + 1
 		}
 	}
+
+	// Update all Subvols Replica count
+	for idx := range volinfo.Subvols {
+		volinfo.Subvols[idx].ReplicaCount = newReplicaCount
+	}
+
 	volinfo.DistCount = len(volinfo.Subvols)
 
 	// update new volinfo in txn ctx