fc_util.go.multiple-wwns-fix.diff

diff --git a/pkg/volume/fc/fc_util.go b/pkg/volume/fc/fc_util.go
index 3da5396..1b22450 100644
--- a/pkg/volume/fc/fc_util.go
+++ b/pkg/volume/fc/fc_util.go
@@ -127,53 +127,65 @@ func (util *FCUtil) MakeGlobalPDName(fc fcDisk) string {
 	return makePDNameInternal(fc.plugin.host, fc.wwns, fc.lun)
 }
 
-func searchDisk(wwns []string, lun string, io ioHandler) (string, string) {
-	disk := ""
-	dm := ""
-
-	rescaned := false
-	// two-phase search:
-	// first phase, search existing device path, if a multipath dm is found, exit loop
-	// otherwise, in second phase, rescan scsi bus and search again, return with any findings
-	for true {
-		for _, wwn := range wwns {
-			disk, dm = findDisk(wwn, lun, io)
-			// if multipath device is found, break
-			if dm != "" {
-				break
-			}
+// Try to find a device-mapper multipath-backed FC disk or, as a fallback,
+// plain old /dev/sd* device.
+func searchDisk(wwns []string, lun string, io ioHandler) string {
+	glog.Infof("fc: searchDisk. Trying to find a matching device for wwns: %v; lun: %v", wwns, lun)
+	// first, try to find a device-mapper device with a path to a WWN from the list
+	for _, wwn := range wwns {
+		glog.Infof("fc: looking for wwn: %v; lun: %v", wwn, lun)
+		_, dm := findDisk(wwn, lun, io)
+		if dm != "" {
+			glog.Infof("fc: found DM multipath device: %v for wwn: %v; lun: %v", dm, wwn, lun)
+			return dm
+		}
+	}
+
+	// No luck, let's rescan scsi bus and try one more time
+	glog.Infof("fc: No luck finding DM multipath device for wwns: %v; lun: %v, let's try scsi bus rescan", wwns, lun)
+
+	// create multipath conf if it is not there
+	createMultipathConf("/etc/multipath.conf", io)
+
+	// rescan scsi bus
+	scsiHostRescan(io)
+
+	// one more attempt to find device-mapper disk after scsi bus rescan
+	disks := []string{}
+	for _, wwn := range wwns {
+		glog.Infof("fc: looking for wwn: %v; lun: %v", wwn, lun)
+		disk, dm := findDisk(wwn, lun, io)
+		if dm != "" {
+			glog.Infof("fc: found DM multipath device: %v for wwn: %v; lun: %v", dm, wwn, lun)
+			return dm
 		}
-		// if a dm is found, exit loop
-		if rescaned || dm != "" {
-			break
+		if disk != "" {
+			glog.Infof("fc: found plain old /dev/sd* disk: %v for wwn: %v; lun: %v", disk, wwn, lun)
+			disks = append(disks, disk)
 		}
-		// rescan and search again
-		// create multipath conf if it is not there
-		createMultipathConf("/etc/multipath.conf", io)
-		// rescan scsi bus
-		scsiHostRescan(io)
-		rescaned = true
 	}
-	return disk, dm
+
+	// fallback to regular /dev/sd* disk if we found one
+	if len(disks) > 0 {
+		glog.Infof("fc: found plain old /dev/sd* disks: %v. Returning: %v", disks, disks[0])
+		return disks[0]
+	}
+
+	glog.Infof("fc: failed to find any matching disks for wwns: %v; lun %v", wwns, lun)
+	return ""
 }
 
 func (util *FCUtil) AttachDisk(b fcDiskMounter) error {
-	devicePath := ""
 	wwns := b.wwns
 	lun := b.lun
 	io := b.io
-	disk, dm := searchDisk(wwns, lun, io)
+
+	devicePath := searchDisk(wwns, lun, io)
 	// if no disk matches input wwn and lun, exit
-	if disk == "" && dm == "" {
-		return fmt.Errorf("no fc disk found")
+	if devicePath == "" {
+		return fmt.Errorf("fc: failed to find a device with matching target WWNs and LUN")
 	}
 
-	// if multipath devicemapper device is found, use it; otherwise use raw disk
-	if dm != "" {
-		devicePath = dm
-	} else {
-		devicePath = disk
-	}
 	// mount it
 	globalPDPath := b.manager.MakeGlobalPDName(*b.fcDisk)
 	noMnt, err := b.mounter.IsLikelyNotMountPoint(globalPDPath)