s3: smbd: Add async internals of reply_close().

Waits until all aio requests on the closing fsps
before returning to the client.

Slightly modified version of the existing async
reply_close code, updated to use the wait_queue
pattern standardized in reply_tdis, reply_ulogoffX
and reply_exit.

Done this way (commented out) so it is a clean
diff and it's clear what is being added.

The next commit will remove the old version.

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>

source3/smbd/reply.c

@@ -6145,6 +6145,135 @@ static void do_smb1_close(struct tevent_req *req)
 	smb_request_done(smb1req);
 }
 
+#if 0
+struct reply_close_state {
+	files_struct *fsp;
+	struct tevent_queue *wait_queue;
+};
+
+static void reply_close_wait_done(struct tevent_req *subreq);
+
+/****************************************************************************
+ Async SMB1 close.
+ Note, on failure here we deallocate and return NULL to allow the caller to
+ SMB1 return an error of ERRnomem immediately.
+****************************************************************************/
+
+static struct tevent_req *reply_close_send(struct smb_request *smb1req,
+				files_struct *fsp)
+{
+	struct tevent_req *req;
+	struct reply_close_state *state;
+	struct tevent_req *subreq;
+	struct smbd_server_connection *sconn = smb1req->sconn;
+
+	req = tevent_req_create(smb1req, &state,
+			struct reply_close_state);
+	if (req == NULL) {
+		return NULL;
+	}
+	state->wait_queue = tevent_queue_create(state,
+				"reply_close_wait_queue");
+	if (tevent_req_nomem(state->wait_queue, req)) {
+		TALLOC_FREE(req);
+		return NULL;
+	}
+
+	/*
+	 * Flag the file as close in progress.
+	 * This will prevent any more IO being
+	 * done on it.
+	 */
+	fsp->closing = true;
+
+	/*
+	 * Now wait until all aio requests on this fsp are
+	 * finished.
+	 *
+	 * We don't set a callback, as we just want to block the
+	 * wait queue and the talloc_free() of fsp->aio_request
+	 * will remove the item from the wait queue.
+	 */
+	subreq = tevent_queue_wait_send(fsp->aio_requests,
+					sconn->ev_ctx,
+					state->wait_queue);
+	if (tevent_req_nomem(subreq, req)) {
+		TALLOC_FREE(req);
+		return NULL;
+	}
+
+	/*
+	 * Now we add our own waiter to the end of the queue,
+	 * this way we get notified when all pending requests are finished
+	 * and reply to the outstanding SMB1 request.
+	 */
+	subreq = tevent_queue_wait_send(state,
+				sconn->ev_ctx,
+				state->wait_queue);
+	if (tevent_req_nomem(subreq, req)) {
+		TALLOC_FREE(req);
+		return NULL;
+	}
+
+	/*
+	 * We're really going async - move the SMB1 request from
+	 * a talloc stackframe above us to the conn talloc-context.
+	 * We need this to stick around until the wait_done
+	 * callback is invoked.
+	 */
+	smb1req = talloc_move(sconn, &smb1req);
+
+	tevent_req_set_callback(subreq, reply_close_wait_done, req);
+
+	return req;
+}
+
+static void reply_close_wait_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req = tevent_req_callback_data(
+		subreq, struct tevent_req);
+
+	tevent_queue_wait_recv(subreq);
+	TALLOC_FREE(subreq);
+	tevent_req_done(req);
+}
+
+static NTSTATUS reply_close_recv(struct tevent_req *req)
+{
+	return tevent_req_simple_recv_ntstatus(req);
+}
+
+static void reply_close_done(struct tevent_req *req)
+{
+	struct smb_request *smb1req = tevent_req_callback_data(
+			req, struct smb_request);
+        struct reply_close_state *state = tevent_req_data(req,
+                                                struct reply_close_state);
+	NTSTATUS status;
+
+	status = reply_close_recv(req);
+	TALLOC_FREE(req);
+	if (!NT_STATUS_IS_OK(status)) {
+		TALLOC_FREE(smb1req);
+		exit_server(__location__ ": reply_close_recv failed");
+		return;
+	}
+
+	status = close_file(smb1req, state->fsp, NORMAL_CLOSE);
+	if (NT_STATUS_IS_OK(status)) {
+		reply_outbuf(smb1req, 0, 0);
+	} else {
+		reply_nterror(smb1req, status);
+	}
+	/*
+	 * The following call is needed to push the
+	 * reply data back out the socket after async
+	 * return. Plus it frees smb1req.
+	 */
+	smb_request_done(smb1req);
+}
+#endif
+
 /****************************************************************************
  Reply to a writeclose (Core+ protocol).
 ****************************************************************************/