ksmbd: send proper error response in smb2_tree_connect()

Currently, smb2_tree_connect doesn't send an error response packet on
error.

This causes libsmb2 to skip the specific error code and fail with the
following:
 smb2_service failed with : Failed to parse fixed part of command
 payload. Unexpected size of Error reply. Expected 9, got 8
Signed-off-by: Marios Makassikis <mmakassikis@freebox.fr>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/ksmbd/smb2pdu.c

@@ -1928,13 +1928,13 @@ int smb2_tree_connect(struct ksmbd_work *work)
 	if (conn->posix_ext_supported)
 		status.tree_conn->posix_extensions = true;
 
-out_err1:
 	rsp->StructureSize = cpu_to_le16(16);
+	inc_rfc1001_len(work->response_buf, 16);
+out_err1:
 	rsp->Capabilities = 0;
 	rsp->Reserved = 0;
 	/* default manual caching */
 	rsp->ShareFlags = SMB2_SHAREFLAG_MANUAL_CACHING;
-	inc_rfc1001_len(work->response_buf, 16);
 
 	if (!IS_ERR(treename))
 		kfree(treename);
@@ -1967,6 +1967,9 @@ int smb2_tree_connect(struct ksmbd_work *work)
 		rsp->hdr.Status = STATUS_ACCESS_DENIED;
 	}
 
+	if (status.ret != KSMBD_TREE_CONN_STATUS_OK)
+		smb2_set_err_rsp(work);
+
 	return rc;
 }