object layer initialization using distributed locking (#2397)

* vendorized latest minio/dsync

* wip - object layer initialization using distributed locking

cmd/server-main.go

@@ -21,11 +21,13 @@ import (
 	"net"
 	"net/http"
 	"os"
+	"path"
 	"strconv"
 	"strings"
 	"time"
 
 	"github.com/minio/cli"
+	"github.com/minio/dsync"
 )
 
 var srvConfig serverCmdConfig
@@ -220,6 +222,29 @@ func getPort(address string) int {
 	return portInt
 }
 
+// Initialize distributed locking only in case of distributed setup.
+func initDsyncNodes(disks []string, port int) error {
+	var isDist bool = false
+	var dsyncNodes []string
+	var rpcPaths []string
+	serverPort := strconv.Itoa(port)
+
+	for _, disk := range disks {
+		if idx := strings.LastIndex(disk, ":"); idx != -1 {
+			dsyncNodes = append(dsyncNodes, disk[:idx]+":"+serverPort)
+			rpcPaths = append(rpcPaths, path.Join(lockRPCPath, disk[idx+1:]))
+		}
+		if !isLocalStorage(disk) {
+			// One or more disks supplied as arguments are remote.
+			isDist = true
+		}
+	}
+	if isDist {
+		return dsync.SetNodesWithPath(dsyncNodes, rpcPaths)
+	}
+	return nil
+}
+
 // serverMain handler called for 'minio server' command.
 func serverMain(c *cli.Context) {
 	// Check 'server' cli arguments.
@@ -245,6 +270,14 @@ func serverMain(c *cli.Context) {
 	// Disks to be used in server init.
 	disks := c.Args()
 
+	// Set nodes for dsync
+	err = initDsyncNodes(disks, port)
+	fatalIf(err, "Unable to initialize distributed locking")
+
+	// Initialize name space lock.
+	// FIXME: add logic to switch between distributed and single-node namespace locking.
+	initNSLock()
+
 	// Configure server.
 	srvConfig = serverCmdConfig{
 		serverAddr:   serverAddress,