diff --git a/diskqueue.go b/diskqueue.go
index 1058c47..3aab8e5 100644
--- a/diskqueue.go
+++ b/diskqueue.go
@@ -425,6 +425,8 @@ func (d *diskQueue) writeOne(data []byte) error {
 		return fmt.Errorf("invalid message write size (%d) minMsgSize=%d maxMsgSize=%d", dataLen, d.minMsgSize, d.maxMsgSize)
 	}
 
+	// add all data to writeBuf before writing to file
+	// this causes everything to be written to file or nothing
 	d.writeBuf.Reset()
 	err = binary.Write(&d.writeBuf, binary.BigEndian, dataLen)
 	if err != nil {
@@ -441,7 +443,7 @@ func (d *diskQueue) writeOne(data []byte) error {
 	// check if we reached the file size limit with this message
 	if d.diskLimitFeatIsOn && d.writePos+totalBytes+8 >= d.maxBytesPerFile {
 		// write number of messages in binary to file
-		err = binary.Write(&d.writeBuf, binary.BigEndian, d.writeMessages)
+		err = binary.Write(&d.writeBuf, binary.BigEndian, d.writeMessages+1)
 		if err != nil {
 			return err
 		}
diff --git a/diskqueue_test.go b/diskqueue_test.go
index a976bb1..8d4f78f 100644
--- a/diskqueue_test.go
+++ b/diskqueue_test.go
@@ -260,7 +260,7 @@ type md struct {
 	writePos      int64
 }
 
-func readMetaDataFile(fileName string, retried int, withDiskSpaceFeat bool) md {
+func readMetaDataFile(fileName string, retried int, diskLimitFeatIsOn bool) md {
 	f, err := os.OpenFile(fileName, os.O_RDONLY, 0600)
 	if err != nil {
 		// provide a simple retry that results in up to
@@ -268,14 +268,15 @@ func readMetaDataFile(fileName string, retried int, withDiskSpaceFeat bool) md {
 		if retried < 9 {
 			retried++
 			time.Sleep(50 * time.Millisecond)
-			return readMetaDataFile(fileName, retried, withDiskSpaceFeat)
+			return readMetaDataFile(fileName, retried, diskLimitFeatIsOn)
 		}
 		panic(err)
 	}
 	defer f.Close()
 
 	var ret md
-	if withDiskSpaceFeat {
+
+	if diskLimitFeatIsOn {
 		_, err = fmt.Fscanf(f, "%d\n%d,%d,%d\n%d,%d,%d,%d\n",
 			&ret.depth,
 			&ret.readFileNum, &ret.readMessages, &ret.readPos,
@@ -352,7 +353,8 @@ func TestDiskQueueSyncAfterReadWithDiskSizeImplementation(t *testing.T) {
 	dq := NewWithDiskSpace(dqName, tmpDir, 1<<11, 1<<11, 0, 1<<10, 2500, 50*time.Millisecond, l)
 	defer dq.Close()
 
-	msg := make([]byte, 1000)
+	msgSize := 1000
+	msg := make([]byte, msgSize)
 	dq.Put(msg)
 
 	for i := 0; i < 10; i++ {
@@ -394,12 +396,19 @@ next:
 	panic("fail")
 
 completeWriteFile:
-	dq.Put(msg)
+	// meet the file size limit exactly (2048 bytes) when writeFileNum
+	// equals readFileNum
+	totalBytes := 2 * (msgSize + 4)
+	bytesRemaining := 2048 - (totalBytes + 8)
+	oneByteMsgSizeIncrease := 5
+	dq.Put(make([]byte, bytesRemaining-4-oneByteMsgSizeIncrease))
+	dq.Put(make([]byte, 1))
 
 	for i := 0; i < 10; i++ {
 		// test that write position and messages reset when a new file is created
+		// test the writeFileNum correctly increments
 		d := readMetaDataFile(dq.(*diskQueue).metaDataFileName(), 0, true)
-		if d.depth == 2 &&
+		if d.depth == 3 &&
 			d.writeBytes == 3020 &&
 			d.readFileNum == 0 &&
 			d.writeFileNum == 1 &&
@@ -417,11 +426,13 @@ completeWriteFile:
 completeReadFile:
 	dq.Put(msg)
 
+	<-dq.ReadChan()
 	<-dq.ReadChan()
 	<-dq.ReadChan()
 
 	for i := 0; i < 10; i++ {
 		// test that read position and messages reset when a file is completely read
+		// test the readFileNum correctly increments
 		d := readMetaDataFile(dq.(*diskQueue).metaDataFileName(), 0, true)
 		t.Logf("Write bytes: %d", d.writeBytes)
 		if d.depth == 1 &&
@@ -433,6 +444,64 @@ completeReadFile:
 			d.readMessages == 0 &&
 			d.writeMessages == 1 {
 			// success
+			goto completeWriteFileAgain
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+	panic("fail")
+
+completeWriteFileAgain:
+	// make writeFileNum ahead of readFileNum
+	dq.Put(msg)
+	dq.Put(msg)
+
+	// meet the file size limit exactly (2048 bytes) when writeFileNum
+	// is ahead of readFileNum
+	dq.Put(msg)
+	dq.Put(msg)
+	dq.Put(make([]byte, bytesRemaining-4-oneByteMsgSizeIncrease))
+	dq.Put(make([]byte, 1))
+
+	for i := 0; i < 10; i++ {
+		// test that write position and messages reset when a file is completely read
+		// test the writeFileNum correctly increments
+		d := readMetaDataFile(dq.(*diskQueue).metaDataFileName(), 0, true)
+		if d.depth == 7 &&
+			d.readFileNum == 1 &&
+			d.writeFileNum == 3 &&
+			d.readPos == 0 &&
+			d.writePos == 0 &&
+			d.readMessages == 0 &&
+			d.writeMessages == 0 {
+			// success
+			goto completeReadFileAgain
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+	panic("fail")
+
+completeReadFileAgain:
+	<-dq.ReadChan()
+	<-dq.ReadChan()
+	<-dq.ReadChan()
+
+	<-dq.ReadChan()
+	<-dq.ReadChan()
+	<-dq.ReadChan()
+	<-dq.ReadChan()
+
+	for i := 0; i < 10; i++ {
+		// test that read position and messages reset when a file is completely read
+		// test the readFileNum correctly increments
+		d := readMetaDataFile(dq.(*diskQueue).metaDataFileName(), 0, true)
+		if d.depth == 0 &&
+			d.readFileNum == 3 &&
+			d.writeFileNum == 3 &&
+			d.readPos == 0 &&
+			d.writePos == 0 &&
+			d.readMessages == 0 &&
+			d.writeMessages == 0 {
+			// success
 			goto done
 		}
 		time.Sleep(100 * time.Millisecond)