.

wcfs/wcfs.go

@@ -281,7 +281,7 @@ package main
 //	FIXME no - we can build it but not in full - since we consider only zobj in live cache.
 //	FIXME and even if we consider all δ'ed zobj, building complete set of
 //	      file.δtail requires to first do complete scan of file.blktab
-//	      which is prohibitively expensive.
+//	      which is prohibitively expensive. XXX -> no, we'll do the scan
 //
 //    4.4) for all file/blk to invalidate we do:
 //
@@ -537,8 +537,11 @@ type BigFile struct {
 	size    int64    // zfile.Size()
 	rev     zodb.Tid // last revision that modified zfile data
 
-//	// tail change history of this file.
-//	δtail *ΔTailI64 // [](rev↑, []#blk)	XXX kill
+	// tail change history of this file.
+	//
+	// XXX computationally expensive to start - see "Invalidations to wcfs
+	// clients are delayed ..." in notes.txt
+	δtail *ΔTailI64 // [](rev↑, []#blk)
 
 	// inflight loadings of ZBigFile from ZODB.
 	// successful load results are kept here until blkdata is put into OS pagecache.
@@ -812,14 +815,15 @@ retry:
 	δF := bfdir.δFtail.Update(δZ)
 	//fmt.Printf("xfiles: %v\n", xfiles)
 	for file, δfile := range δF.Change {
-		// XXX use δfile blocks
-		_ = δfile
 		finv, ok := toinvalidate[file]
 		if !ok {
 			finv = &fileInvalidate{} // XXX init blkmap?
 			toinvalidate[file] = finv
 		}
+		// XXX use δfile blocks -> finv.blkmap
 		finv.size = true
+
+		file.δtail.Append(δF.Rev, δfile.Elements())
 	}
 
 	//fmt.Printf("\n\nzδhandle: toinvalidate (#%d):\n", len(toinvalidate))
@@ -898,6 +902,7 @@ retry:
 	}
 
 	// XXX δFtail.ForgetPast(...)
+	// XXX for f in toinvalidate: f.δtail.ForgetPast(...)
 }
 
 // invalidateBlk invalidates 1 file block in kernel cache.
@@ -1367,20 +1372,18 @@ func (wlink *WatchLink) setupWatch(ctx context.Context, foid zodb.Oid, at zodb.T
 		return fmt.Errorf("at is too far away back from head/at")
 	}
 
-	// XXX register w to f early, so that READs going in parallel to us
+	// TODO register w to f here early, so that READs going in parallel to us
 	// preparing and processing initial pins, also sends pin for read
 	// blocks. If we don't we can miss to send pin for a freshly read which
 	// could have revision > w.at .
 
 	toPin := map[int64]zodb.Tid{} // blk -> @rev
 
-	// XXX locking ok?
-	bfdir.δFmu.RLock()
-	defer bfdir.δFmu.RUnlock()
+	// XXX locking
 
 	// pin all tracked file blocks that were changed (at, head] range
-	for _, δfile := range bfdir.δFtail.SliceByFileRev(f, at, head.zconn.At()) {
-		for blk := range δfile.Change {
+	for _, δfile := range f.δtail.SliceByRev(at, head.zconn.At()) {
+		for _, blk := range δfile.Changev {
 			_, already := toPin[blk]
 			if already {
 				continue
@@ -1737,7 +1740,6 @@ func (head *Head) bigopen(ctx context.Context, oid zodb.Oid) (_ *BigFile, err er
 		return nil, err
 	}
 
-//	zconn.Incref()
 	f := &BigFile{
 		fsNode:  newFSNode(&fsOptions{Sticky: false}),	// XXX + BigFile.OnForget -> del .head.bfdir.fileTab[]
 		head:    head,
@@ -1745,17 +1747,19 @@ func (head *Head) bigopen(ctx context.Context, oid zodb.Oid) (_ *BigFile, err er
 		blksize: blksize,
 		size:    size,
 		rev:     rev,
-
-//		// XXX this is needed only for head/
-//		δtail:   NewΔTailI64(zconn.At()),
 		loading: make(map[int64]*blkLoadState),
 	}
 
-	// only head/ needs δFtail.
+	// only head/ needs f.δtail
+
+
+	// only head/ needs δFtail & f.δtail.
 	if head.rev == 0 {
 		head.bfdir.δFmu.Lock()	// XXX locking ok?
 		head.bfdir.δFtail.Track(f, treePath)
 		head.bfdir.δFmu.Unlock()
+
+		f.δtail = NewΔTailI64(zconn.At())
 	}
 
 	return f, nil