NFSv4.x: Drop the slot if nfs4_delegreturn_prepare waits for layoutreturn

If nfs4_delegreturn_prepare needs to wait for a layoutreturn to complete
then make sure we drop the sequence slot if we hold it.

Fixes: 1c5bd76d ("pNFS: Enable layoutreturn operation for return-on-close")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/nfs4proc.c

@@ -6256,8 +6256,10 @@ static void nfs4_delegreturn_prepare(struct rpc_task *task, void *data)
 
 	d_data = (struct nfs4_delegreturndata *)data;
 
-	if (!d_data->lr.roc && nfs4_wait_on_layoutreturn(d_data->inode, task))
+	if (!d_data->lr.roc && nfs4_wait_on_layoutreturn(d_data->inode, task)) {
+		nfs4_sequence_done(task, &d_data->res.seq_res);
 		return;
+	}
 
 	lo = d_data->args.lr_args ? d_data->args.lr_args->layout : NULL;
 	if (lo && !pnfs_layout_is_valid(lo)) {