arbiter: Support replica 2 arbiter 1 usage

Signed-off-by: Prashanth Pai <ppai@redhat.com>

Author: prashanthpai

e2e/smartvol_ops_test.go

@@ -106,7 +106,7 @@ func testSmartVolumeArbiter(t *testing.T) {
 	createReq := api.VolCreateReq{
 		Name:         smartvolname,
 		Size:         20,
-		ReplicaCount: 3,
+		ReplicaCount: 2,
 		ArbiterCount: 1,
 	}
 	volinfo, err := client.VolumeCreate(createReq)

glustercli/cmd/volume-create.go

@@ -166,26 +166,43 @@ func volumeCreateCmdRun(cmd *cobra.Command, args []string) {
 	if flagCreateReplicaCount > 0 {
 		// Replicate Volume Support
 
-		if numBricks%flagCreateReplicaCount != 0 {
-			failure("Invalid number of bricks specified", nil, 1)
+		// if arbiter count is specified
+		if cmd.Flags().Changed("arbiter") {
+			if flagCreateArbiterCount != 1 && flagCreateReplicaCount != 2 {
+				failure("Invalid arbiter/replica count specified. Supported arbiter configuration: replica 2, arbiter 1", nil, 1)
+			}
+		}
+
+		if numBricks%(flagCreateReplicaCount+flagCreateArbiterCount) != 0 {
+			failure("Invalid number of bricks specified. Number of bricks must be a multiple of replica (+arbiter) count.", nil, 1)
 		}
 
-		numSubvols := numBricks / flagCreateReplicaCount
+		// FIXME: Things would've been so much simpler if specifying the
+		// arbiter brick was simply a separate command flag such as
+		// --arbiter-brick or even a boolean as we always pick the last
+		// brick as arbiter.
+
+		numSubvols := numBricks / (flagCreateReplicaCount + flagCreateArbiterCount)
 
+		subvolStart := 0
+		subvolEnd := flagCreateReplicaCount + flagCreateArbiterCount
 		for i := 0; i < numSubvols; i++ {
-			idx := i * flagCreateReplicaCount
 
-			// If Arbiter is set, set it as Brick Type for last brick
+			// If arbiter count is set, mark the brick type of last
+			// brick in the subvol as of Arbiter type.
 			if flagCreateArbiterCount > 0 {
-				bricks[idx+flagCreateReplicaCount-1].Type = "arbiter"
+				bricks[subvolEnd-1].Type = "arbiter"
 			}
 
 			subvols = append(subvols, api.SubvolReq{
 				Type:         "replicate",
-				Bricks:       bricks[idx : idx+flagCreateReplicaCount],
+				Bricks:       bricks[subvolStart:subvolEnd],
 				ReplicaCount: flagCreateReplicaCount,
 				ArbiterCount: flagCreateArbiterCount,
 			})
+
+			subvolStart = subvolEnd
+			subvolEnd += (flagCreateReplicaCount + flagCreateArbiterCount)
 		}
 	} else if flagCreateDisperseCount > 0 || flagCreateDisperseDataCount > 0 || flagCreateDisperseRedundancyCount > 0 {
 		subvolSize := 0

glusterd2/bricksplanner/subvoltype_replicate.go

@@ -22,19 +22,19 @@ func (s *replicaSubvolPlanner) Init(req *api.VolCreateReq, subvolSize uint64) {
 }
 
 func (s *replicaSubvolPlanner) BricksCount() int {
-	return s.replicaCount
+	return s.replicaCount + s.arbiterCount
 }
 
 func (s *replicaSubvolPlanner) BrickSize(idx int) uint64 {
-	if idx == (s.replicaCount-1) && s.arbiterCount > 0 {
+	if idx == (s.replicaCount) && s.arbiterCount > 0 {
 		return s.arbiterBrickSize
 	}
 
 	return s.brickSize
 }
 
 func (s *replicaSubvolPlanner) BrickType(idx int) string {
-	if idx == (s.replicaCount-1) && s.arbiterCount > 0 {
+	if idx == (s.replicaCount) && s.arbiterCount > 0 {
 		return "arbiter"
 	}
 

glusterd2/commands/volumes/volume-create-txn.go

@@ -65,8 +65,8 @@ func populateSubvols(volinfo *volume.Volinfo, req *api.VolCreateReq) error {
 			return errors.New("replica count not specified")
 		}
 
-		if subvolreq.ReplicaCount > 0 && subvolreq.ReplicaCount != len(subvolreq.Bricks) {
-			return errors.New("invalid number of bricks")
+		if subvolreq.ReplicaCount > 0 && (subvolreq.ReplicaCount+subvolreq.ArbiterCount) != len(subvolreq.Bricks) {
+			return errors.New("invalid number of bricks specified. Number of bricks must be a multiple of replica (+arbiter) count")
 		}
 
 		name := fmt.Sprintf("%s-%s-%d", volinfo.Name, strings.ToLower(subvolreq.Type), idx)
@@ -88,8 +88,8 @@ func populateSubvols(volinfo *volume.Volinfo, req *api.VolCreateReq) error {
 		}
 
 		if subvolreq.ArbiterCount != 0 {
-			if subvolreq.ReplicaCount != 3 || subvolreq.ArbiterCount != 1 {
-				return errors.New("for arbiter configuration, replica count must be 3 and arbiter count must be 1. The 3rd brick of the replica will be the arbiter")
+			if subvolreq.ReplicaCount != 2 || subvolreq.ArbiterCount != 1 {
+				return errors.New("for arbiter configuration, replica count must be 2 and arbiter count must be 1. The 3rd brick of the replica will be the arbiter")
 			}
 			s.ArbiterCount = 1
 		}