Fixes for filestore not remember first sequence when all messages deleted.

Thsi fixed a few minor bugs as well as the one where we did not remember our sequence numbers.

Signed-off-by: Derek Collison <derek@nats.io>

server/filestore.go

@@ -606,6 +606,10 @@ func (fs *fileStore) newMsgBlockForWrite() (*msgBlock, error) {
 	ts := time.Now().UnixNano()
 	mb.llts, mb.lrts, mb.lwts = ts, ts, ts
 
+	// Remember our last sequence number.
+	mb.first.seq = fs.state.LastSeq + 1
+	mb.last.seq = fs.state.LastSeq
+
 	// We know we will need this so go ahead and spin up.
 	mb.spinUpFlushLoop()
 
@@ -1148,6 +1152,7 @@ func (mb *msgBlock) selectNextFirst() {
 	}
 	// Set new first sequence.
 	mb.first.seq = seq
+
 	// Check if we are empty..
 	if mb.isEmpty() {
 		mb.first.ts = 0
@@ -1381,8 +1386,8 @@ func (fs *fileStore) checkAndFlushAllBlocks() {
 	for _, mb := range fs.blks {
 		if mb.pendingWriteSize() > 0 {
 			mb.flushPendingMsgsAndWait()
-			mb.writeIndexInfo()
 		}
+		mb.writeIndexInfo()
 	}
 }
 
@@ -1562,7 +1567,7 @@ func (mb *msgBlock) numBytes() uint64 {
 // Update accounting on a write msg.
 // Lock should be held.
 func (mb *msgBlock) updateAccounting(seq uint64, ts int64, rl uint64) {
-	if mb.first.seq == 0 {
+	if mb.first.seq == 0 || mb.first.ts == 0 {
 		mb.first.seq = seq
 		mb.first.ts = ts
 	}
@@ -2416,7 +2421,7 @@ func (mb *msgBlock) dirtyClose() {
 
 // Should be called with lock held.
 func (mb *msgBlock) dirtyCloseWithRemove(remove bool) {
-	if mb == nil || mb.qch == nil {
+	if mb == nil {
 		return
 	}
 	// Close cache

server/filestore_test.go

@@ -224,6 +224,41 @@ func TestFileStoreBasicWriteMsgsAndRestore(t *testing.T) {
 	if state.Bytes != expectedSize*2 {
 		t.Fatalf("Expected %d bytes, got %d", expectedSize*2, state.Bytes)
 	}
+
+	fs.Purge()
+	fs.Stop()
+
+	fs, err = newFileStore(fcfg, StreamConfig{Name: "dlc", Storage: FileStorage})
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	defer fs.Stop()
+
+	state = fs.State()
+	if state.Msgs != 0 {
+		t.Fatalf("Expected %d msgs, got %d", 0, state.Msgs)
+	}
+	if state.Bytes != 0 {
+		t.Fatalf("Expected %d bytes, got %d", 0, state.Bytes)
+	}
+
+	seq, _, err := fs.StoreMsg(subj, nil, []byte("Hello"))
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	fs.RemoveMsg(seq)
+
+	fs.Stop()
+	fs, err = newFileStore(fcfg, StreamConfig{Name: "dlc", Storage: FileStorage})
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	defer fs.Stop()
+
+	state = fs.State()
+	if state.FirstSeq != seq+1 {
+		t.Fatalf("Expected first seq to be %d, got %d", seq+1, state.FirstSeq)
+	}
 }
 
 func TestFileStoreSelectNextFirst(t *testing.T) {
@@ -803,7 +838,7 @@ func TestFileStoreRemoveOutOfOrderRecovery(t *testing.T) {
 
 	state2 := fs.State()
 	if state != state2 {
-		t.Fatalf("Expected receovered states to be the same, got %+v vs %+v\n", state, state2)
+		t.Fatalf("Expected recovered states to be the same, got %+v vs %+v\n", state, state2)
 	}
 
 	if _, _, _, _, err := fs.LoadMsg(1); err != nil {