rbd: do not try to run resizefs on an encrypted BlockMode volume

When a volume has AccessType=Block and is encrypted with LUKS, a resize
of the filesystem on the (decrypted) block-device is attempted. This
should not be done, as the application that requested the Block volume
is the only authoritive reader/writer of the data.

In particular VirtualMachines that use RBD volumes as a disk, usually
have a partition table on the disk, instead of only a single filesystem.
The `resizefs` command will not be able to resize the filesystem on the
block-device, as it is a partition table.

When `resizefs` fails during NodeStageVolume, the volume is unstaged and
an error is returned.

Resizing an encrypted block-device requires `cryptsetup resize` so that
the LUKS header on the RBD-image is updated with the correct size. But
there is no need to call `resizefs` in this case.

Fixes: #3945
Signed-off-by: Niels de Vos <ndevos@ibm.com>

internal/rbd/nodeserver.go

@@ -512,6 +512,14 @@ func resizeNodeStagePath(ctx context.Context,
 		if err != nil {
 			return status.Error(codes.Internal, err.Error())
 		}
+
+		// If this is a AccessType=Block volume, do not attempt
+		// filesystem resize. The application is in charge of the data
+		// on top of the raw block-device, we can not assume there is a
+		// filesystem at all.
+		if isBlock {
+			return nil
+		}
 	}
 	// check stagingPath needs resize.
 	ok, err = resizer.NeedResize(devicePath, stagingTargetPath)