.

wcfs/wcfs.go

@@ -546,8 +546,7 @@ func (r *Root) zhandle1(zevent zodb.WatchEvent) {
 	defer r.head.zconnMu.Unlock()
 	zhead := r.head.zconn
 
-	//toinvalidate := map[*ZBigFile]SetI64{} // {} zfile -> set(#blk)
-	toinvalidate := map[*BigFile]SetI64{} // {} zfile -> set(#blk)
+	toinvalidate := map[*BigFile]SetI64{} // {} file -> set(#blk)
 
 	// zevent = (tid^, []oid)
 	for _, oid := range zevent.Changev {
@@ -567,14 +566,17 @@ func (r *Root) zhandle1(zevent zodb.WatchEvent) {
 			// XXX -> δBTree
 
 		case zBlk:	// ZBlk*
-			// XXX locking ?
-			for zfile, objWhere := range obj.inzfile {
+			// blkBoundTo locking: no other bindZFile are running,
+			// since we write-locked head.zconnMu and bindZFile is
+			// run when loading objects - thus when head.zconnMu is
+			// read-locked.
+			for zfile, objBlk := range obj.blkBoundTo() {
 				blkmap, ok := toinvalidate[zfile]
 				if !ok {
 					blkmap = SetI64{}
 					toinvalidate[zfile] = blkmap
 				}
-				blkmap.Update(objWhere)
+				blkmap.Update(objBlk)
 			}
 
 		case *ZBigFile:

wcfs/zblk.go

@@ -69,16 +69,24 @@ type zBlk interface {
 	// A ZBlk may be bound to several blocks inside one file, and to
 	// several files.
 	//
-	// XXX the information is preserved even when ZBlk comes to ghost
+	// The information is preserved even when ZBlk comes to ghost
 	// state, but is lost if ZBlk is garbage collected.
 	//
-	// bindZFile is safe for concurrent access.
+	// it is safe to call multiple bindZFile simultaneously.
+	// it is not safe to call bindZFile and boundTo simultaneously.
 	//
 	// XXX link to overview.
 	bindZFile(zfile *ZBigFile, blk int64)
 
 	// XXX unbindZFile
 	// XXX zfile -> bind map for it
+
+	// blkBoundTo returns ZBlk association with zfile(s)/#blk(s).
+	//
+	// The association returned is that was previously set by bindZFile.
+	//
+	// blkBoundTo must not be called simultaneously wrt bindZFile.
+	blkBoundTo() map[*ZBigFile]SetI64
 }
 
 // module of Wendelin ZODB py objects
@@ -91,14 +99,14 @@ const zwendelin = "wendelin.bigfile.file_zodb"
 // The data stored by zBlkBase is transient - it is _not_ included into
 // persistent state.
 type zBlkBase struct {
-	mu      sync.Mutex
+	bindMu  sync.Mutex           // used only for binding to support multiple loaders
 	inzfile map[*ZBigFile]SetI64 // {} zfile -> set(#blk)
 }
 
 // bindZFile implements zBlk.
 func (zb *zBlkBase) bindZFile(zfile *ZBigFile, blk int64) {
-	zb.mu.Lock()
-	defer zb.mu.Unlock()
+	zb.bindMu.Lock()
+	defer zb.bindMu.Unlock()
 
 	blkmap, ok := zb.inzfile[zfile]
 	if !ok {
@@ -111,6 +119,11 @@ func (zb *zBlkBase) bindZFile(zfile *ZBigFile, blk int64) {
 	blkmap.Add(blk)
 }
 
+// blkBoundTo implementss zBlk.
+func (zb *zBlkBase) blkBoundTo() map[*ZBigFile]SetI64 {
+	return zb.inzfile
+}
+
 // ---- ZBlk0 ----
 
 // ZBlk0 mimics ZBlk0 from python.