Add controller unpublish nvme volume fault points

Signed-off-by: Meghna Singh <ms73385@netapp.com>

Author: singhmeghna79

storage_drivers/ontap/ontap_san_nvme.go

@@ -18,6 +18,7 @@ import (
 	"github.com/RoaringBitmap/roaring/v2"
 
 	tridentconfig "github.com/netapp/trident/config"
+	"github.com/netapp/trident/internal/fiji"
 	. "github.com/netapp/trident/logging"
 	"github.com/netapp/trident/pkg/capacity"
 	"github.com/netapp/trident/pkg/collection"
@@ -38,6 +39,11 @@ import (
 // string of the form /vol/<flexVolName>/<Namespacename>
 var NVMeNamespaceRegExp = regexp.MustCompile(`[^(\/vol\/.+\/.+)?$]`)
 
+var (
+	beforeNQNRemovalFromSubsystem     = fiji.Register("beforeNQNRemovalFromSubsystem", "ontap_san_nvme")
+	beforeNamespaceUnmapFromSubsystem = fiji.Register("beforeNamespaceUnmapFromSubsystem", "ontap_san_nvme")
+)
+
 // NVMeStorageDriver is for NVMe storage provisioning.
 type NVMeStorageDriver struct {
 	initialized bool
@@ -1044,6 +1050,10 @@ func (d *NVMeStorageDriver) Unpublish(
 	unlock := lockNamespaceAndSubsystem(namespaceUUID, subsystemUUID)
 	defer unlock()
 
+	if err := beforeNQNRemovalFromSubsystem.Inject(); err != nil {
+		return err
+	}
+
 	// Remove host from subsystem if it has no other published volumes from this subsystem
 	_, err := RemoveHostFromSubsystem(
 		ctx,
@@ -1056,6 +1066,10 @@ func (d *NVMeStorageDriver) Unpublish(
 		return fmt.Errorf("failed to remove host from subsystem: %w", err)
 	}
 
+	if err := beforeNamespaceUnmapFromSubsystem.Inject(); err != nil {
+		return err
+	}
+
 	// Unmap namespace from subsystem if no other hosts in SS need it
 	namespaceUnmapped, err := UnmapNamespaceFromSubsystem(
 		ctx,