Test for read buffers too.

fuse/mountstate.go

@@ -41,6 +41,7 @@ type MountState struct {
 	reqPool []*request
 	readPool [][]byte
 	reqReaders int
+	outstandingReadBufs int
 }
 
 func (ms *MountState) KernelSettings() raw.InitIn {
@@ -168,6 +169,7 @@ func (ms *MountState) readRequest() (req *request, code Status) {
 	} else {
 		dest = make([]byte, ms.opts.MaxWrite + 4096)
 	}
+	ms.outstandingReadBufs++
 	ms.reqReaders++
 	ms.reqMu.Unlock()
 
@@ -185,6 +187,7 @@ func (ms *MountState) readRequest() (req *request, code Status) {
 
 	ms.reqMu.Lock()
 	if !gobbled {
+		ms.outstandingReadBufs--
 		ms.readPool = append(ms.readPool, dest)
 		dest = nil
 	}
@@ -206,6 +209,7 @@ func (ms *MountState) returnRequest(req *request) {
 	ms.reqMu.Lock()
 	if req.bufferPoolOutputBuf != nil {
 		ms.readPool = append(ms.readPool, req.bufferPoolInputBuf)
+		ms.outstandingReadBufs--
 		req.bufferPoolInputBuf = nil
 	}
 	ms.reqPool = append(ms.reqPool, req)

fuse/pressure_test.go

@@ -58,9 +58,12 @@ func TestMemoryPressure(t *testing.T) {
 		}(i)
 	}
 	time.Sleep(100 * time.Millisecond)
-	created := state.buffers.createdBuffers
+	created := state.buffers.createdBuffers + state.outstandingReadBufs
+	t.Logf("Have %d read bufs", state.outstandingReadBufs)
 	if created > 2 * _MAX_READERS {
 		t.Errorf("created %d buffers, max reader %d", created, _MAX_READERS)
 	}
+
+
 	wg.Wait()
 }