discard error message if node is unreachable and DontCheckAlive flag is set

if nodes are unreachable and DontCheckAlive flag is set,
we need to discard the error message and return nil

Signed-off-by: Madhu Rajanna <mrajanna@redhat.com>

glusterd2/transaction/transaction.go

@@ -13,6 +13,8 @@ import (
 	"github.com/coreos/etcd/clientv3/concurrency"
 	"github.com/pborman/uuid"
 	log "github.com/sirupsen/logrus"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
 )
 
 const (
@@ -133,6 +135,9 @@ func (t *Txn) Do() error {
 		}
 
 		if err := s.do(t.OrigCtx, t.Ctx); err != nil {
+			if t.DontCheckAlive && isNodeUnreachable(err) {
+				continue
+			}
 			expTxn.Add("initiated_txn_failure", 1)
 			if !t.DisableRollback {
 				t.Ctx.Logger().WithError(err).Error("Transaction failed, rolling back changes")
@@ -146,6 +151,18 @@ func (t *Txn) Do() error {
 	return nil
 }
 
+func isNodeUnreachable(err error) bool {
+	unreachable := true
+	if s, ok := err.(*stepResp); ok {
+		for _, e := range s.Resps {
+			if grpc.Code(e.Error) != codes.Unavailable {
+				unreachable = false
+			}
+		}
+	}
+	return unreachable
+}
+
 // undo undoes a transaction and will be automatically called by Perform if any step fails.
 // The Steps are undone in the reverse order, from the failed step.
 func (t *Txn) undo(n int) {