Add node info to failed mount logging.

Signed-off-by: James Munson <james.munson@suse.com>

csi/node_server.go

@@ -280,6 +280,9 @@ func (ns *NodeServer) nodeStageSharedVolume(volumeID, shareEndpoint, targetPath
 			if err == nil {
 				return nil
 			}
+			// Still failed.  Log with mounting node and kernel version for possible troubleshooting.
+			osInfo := getOSInfo()
+			log.WithError(err).Warnf("Failed to mount volume %v on node %s with kernel release %s.", volumeID, ns.nodeID, osInfo)
 		}
 		return status.Error(codes.Internal, err.Error())
 	}

csi/util.go

@@ -10,6 +10,7 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"syscall"
 	"time"
 
 	"github.com/container-storage-interface/spec/lib/go/csi"
@@ -460,3 +461,28 @@ func requiresSharedAccess(vol *longhornclient.Volume, cap *csi.VolumeCapability)
 func getStageBlockVolumePath(stagingTargetPath, volumeID string) string {
 	return filepath.Join(stagingTargetPath, volumeID)
 }
+
+// We use this utility function because csi-plugin has no datastore object to ask about kubernetes node,
+// and the go-common-lib/ns functions won't work because the /proc mount path is different.
+func getOSInfo() string {
+	utsname := &syscall.Utsname{}
+	if err := syscall.Uname(utsname); err != nil {
+		logrus.WithError(err).Warn("Failed making syscall Uname.")
+		return "<unknown OS>"
+	}
+
+	extract := func(field [65]int8) string {
+		output := make([]byte, 0, len(field))
+		for _, b := range field {
+			if b == 0x00 {
+				break
+			}
+			output = append(output, byte(b))
+		}
+		return string(output)
+	}
+
+	// Extract the kernel release and OS version from the utsname structure
+	osInfo := extract(utsname.Release) + ", " + extract(utsname.Version)
+	return osInfo
+}