diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index 4832de84..14d04c8 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -150,10 +150,9 @@
 }
 
 /*
- * note that the data in a socket buffer is now delivered and that the buffer
- * should be freed
+ * Note that the data in a socket buffer is now consumed.
  */
-static void afs_data_delivered(struct sk_buff *skb)
+void afs_data_consumed(struct afs_call *call, struct sk_buff *skb)
 {
 	if (!skb) {
 		_debug("DLVR NULL [%d]", atomic_read(&afs_outstanding_skbs));
@@ -161,9 +160,7 @@
 	} else {
 		_debug("DLVR %p{%u} [%d]",
 		       skb, skb->mark, atomic_read(&afs_outstanding_skbs));
-		if (atomic_dec_return(&afs_outstanding_skbs) == -1)
-			BUG();
-		rxrpc_kernel_data_delivered(skb);
+		rxrpc_kernel_data_consumed(call->rxcall, skb);
 	}
 }
 
@@ -489,9 +486,15 @@
 			last = rxrpc_kernel_is_data_last(skb);
 			ret = call->type->deliver(call, skb, last);
 			switch (ret) {
+			case -EAGAIN:
+				if (last) {
+					_debug("short data");
+					goto unmarshal_error;
+				}
+				break;
 			case 0:
-				if (last &&
-				    call->state == AFS_CALL_AWAIT_REPLY)
+				ASSERT(last);
+				if (call->state == AFS_CALL_AWAIT_REPLY)
 					call->state = AFS_CALL_COMPLETE;
 				break;
 			case -ENOTCONN:
@@ -501,6 +504,7 @@
 				abort_code = RX_INVALID_OPERATION;
 				goto do_abort;
 			default:
+			unmarshal_error:
 				abort_code = RXGEN_CC_UNMARSHAL;
 				if (call->state != AFS_CALL_AWAIT_REPLY)
 					abort_code = RXGEN_SS_UNMARSHAL;
@@ -511,9 +515,7 @@
 				call->state = AFS_CALL_ERROR;
 				break;
 			}
-			afs_data_delivered(skb);
-			skb = NULL;
-			continue;
+			break;
 		case RXRPC_SKB_MARK_FINAL_ACK:
 			_debug("Rcv ACK");
 			call->state = AFS_CALL_COMPLETE;
@@ -685,15 +687,35 @@
 }
 
 /*
- * empty a socket buffer into a flat reply buffer
+ * Empty a socket buffer into a flat reply buffer.
  */
-void afs_transfer_reply(struct afs_call *call, struct sk_buff *skb)
+int afs_transfer_reply(struct afs_call *call, struct sk_buff *skb, bool last)
 {
 	size_t len = skb->len;
 
-	if (skb_copy_bits(skb, 0, call->buffer + call->reply_size, len) < 0)
-		BUG();
-	call->reply_size += len;
+	if (len > call->reply_max - call->reply_size) {
+		_leave(" = -EBADMSG [%zu > %u]",
+		       len, call->reply_max - call->reply_size);
+		return -EBADMSG;
+	}
+
+	if (len > 0) {
+		if (skb_copy_bits(skb, 0, call->buffer + call->reply_size,
+				  len) < 0)
+			BUG();
+		call->reply_size += len;
+	}
+
+	afs_data_consumed(call, skb);
+	if (!last)
+		return -EAGAIN;
+
+	if (call->reply_size != call->reply_max) {
+		_leave(" = -EBADMSG [%u != %u]",
+		       call->reply_size, call->reply_max);
+		return -EBADMSG;
+	}
+	return 0;
 }
 
 /*
@@ -745,7 +767,8 @@
 }
 
 /*
- * grab the operation ID from an incoming cache manager call
+ * Grab the operation ID from an incoming cache manager call.  The socket
+ * buffer is discarded on error or if we don't yet have sufficient data.
  */
 static int afs_deliver_cm_op_id(struct afs_call *call, struct sk_buff *skb,
 				bool last)
@@ -766,12 +789,9 @@
 	call->offset += len;
 
 	if (call->offset < 4) {
-		if (last) {
-			_leave(" = -EBADMSG [op ID short]");
-			return -EBADMSG;
-		}
-		_leave(" = 0 [incomplete]");
-		return 0;
+		afs_data_consumed(call, skb);
+		_leave(" = -EAGAIN");
+		return -EAGAIN;
 	}
 
 	call->state = AFS_CALL_AWAIT_REQUEST;
@@ -855,7 +875,7 @@
 }
 
 /*
- * extract a piece of data from the received data socket buffers
+ * Extract a piece of data from the received data socket buffers.
  */
 int afs_extract_data(struct afs_call *call, struct sk_buff *skb,
 		     bool last, void *buf, size_t count)
@@ -873,10 +893,7 @@
 	call->offset += len;
 
 	if (call->offset < count) {
-		if (last) {
-			_leave(" = -EBADMSG [%d < %zu]", call->offset, count);
-			return -EBADMSG;
-		}
+		afs_data_consumed(call, skb);
 		_leave(" = -EAGAIN");
 		return -EAGAIN;
 	}