.

wcfs/wcfs.go

@@ -525,7 +525,7 @@ type BigFileDir struct {
 
 	// δ tail of tracked BTree nodes of all BigFiles + -> which file
 	// (used only for head/, not revX/)
-	δFmu   sync.RWMutex	// XXX doc zheadMu.W  |  ...	?
+	δFmu   sync.RWMutex	// XXX zheadMu.W  |  zheadMu.R + δFmu.X	?
 	δFtail *ΔFtail
 }
 
@@ -694,7 +694,8 @@ func traceZWatch(format string, argv ...interface{}) {
 // see "4) when we receive an invalidation message from ZODB ..."
 func (root *Root) zwatcher(ctx context.Context, zwatchq chan zodb.Event) (err error) {
 	defer xerr.Contextf(&err, "zwatch %s", root.zstor.URL())
-	// XXX error -> always EIO for data operations
+	// XXX error   -> always EIO for data operations
+	// XXX unmount -> stop
 	traceZWatch(">>>")
 
 	var zevent zodb.Event
@@ -768,72 +769,12 @@ retry:
 	zhead := head.zconn
 	bfdir := head.bfdir
 
-/*
-	// δZ = (tid↑, []oid)
-	for _, oid := range δZ.Changev {
-		// XXX zhead.Cache() lock/unlock
-		obj := zhead.Cache().Get(oid)
-		if obj == nil {
-			//fmt.Printf("%s: not in cache\n", oid)
-			continue // nothing to do - see invariant
-		}
-
-		//fmt.Printf("%s:     in cache (%s)\n", oid, typeOf(obj))
-
-		switch obj := obj.(type) {
-		default:
-			continue // object not related to any bigfile
-
-		// XXX kill Tree/Bucket here (-> ΔFtail)
-		case *btree.LOBTree:
-			btreeChangev = append(btreeChangev, obj.POid())
-
-		case *btree.LOBucket:
-			btreeChangev = append(btreeChangev, obj.POid())
-
-		case zBlk:	// ZBlk*
-			// blkBoundTo locking: no other bindZFile are running,
-			// since we write-locked head.zheadMu and bindZFile is
-			// run when loading objects - thus when head.zheadMu is
-			// read-locked.
-			//
-			// bfdir locking: similarly not needed, since we are
-			// exclusively holding head lock.
-			for zfile, objBlk := range obj.blkBoundTo() {
-				file, ok := bfdir.fileTab[zfile.POid()]
-				if !ok {
-					// even though zfile is in ZODB cache, the
-					// filesystem already forgot about this file.
-					continue
-				}
-
-				finv, ok := toinvalidate[file]
-				if !ok {
-					finv = &fileInvalidate{blkmap: SetI64{}}
-					toinvalidate[file] = finv
-				}
-				finv.blkmap.Update(objBlk)
-			}
-
-		case *ZBigFile:
-			// XXX check that .blksize and .blktab (it is only
-			// persistent reference) do not change.
-
-			// XXX shutdown fs with ^^^ message.
-			panic("ZBigFile changed")
-		}
-
-		// make sure obj won't be garbage-collected until we finish handling it.
-		runtime.KeepAlive(obj)
-	}
-*/
-
 	// invalidate kernel cache for data in changed files
-	// XXX no indexMu lock needed because head is Locked
+	// XXX no δFmu lock needed because head is Locked
 	δF := bfdir.δFtail.Update(δZ, zhead)
 
 	if false {
-	fmt.Printf("\n\nS: zδhandle: δF (#%d):\n", len(δF.ByFile))
+	fmt.Printf("\n\nS: handleδZ: δF (#%d):\n", len(δF.ByFile))
 	for file, δfile := range δF.ByFile {
 		blkv := δfile.Blocks.Elements()
 		sort.Slice(blkv, func(i, j int) bool {
@@ -1221,6 +1162,8 @@ func (f *BigFile) readBlk(ctx context.Context, blk int64, dest []byte) (err erro
 	// and thus would trigger DB access again.
 	//
 	// XXX if direct-io: don't touch pagecache
+	// XXX upload parts only not covered by currrent read (not to e.g. wait for page lock)
+	// XXX skip upload completely if read is wide to cover whole blksize
 	go f.uploadBlk(blk, loading)
 
 	return nil
@@ -2296,7 +2239,7 @@ func main() {
 	})
 
 	// XXX place = ok?
-	// XXX ctx = ok?
+	// XXX ctx = ok?	XXX -> joined ctx for fs.Serve + zwatcher ?
 	// XXX wait for zwatcher shutdown + log from it error
 	go root.zwatcher(ctx, zwatchq)