.

wcfs/wcfs.go

@@ -426,7 +426,8 @@ type Root struct {
 type Head struct {
 	nodefs.Node
 	rev   zodb.Tid    // 0 for head/, !0 for @<rev>/
-	// bigfile/, at, watch, etc - all implicitly linked to by fs
+	bfdir *BigFileDir
+	// at, watch, etc - all implicitly linked to by fs
 
 	// ZODB connection for everything under this head
 	zconnMu sync.RWMutex // protects access to zconn & live _objects_ associated with it
@@ -541,10 +542,13 @@ func (r *Root) zwatcher(ctx context.Context) (err error) {
 
 // zhandle1 handles 1 event from ZODB notification.
 func (r *Root) zhandle1(zevent zodb.WatchEvent) {
-	// XXX locking correct? XXX too coarse? -> lock only around "resync .zhead ..." ?
+	// while we are invalidating OS cache, make sure that nothing, that
+	// even reads /head/bigfile/*, is running (see 4.6).
 	r.head.zconnMu.Lock()
 	defer r.head.zconnMu.Unlock()
+
 	zhead := r.head.zconn
+	bfdir := r.head.bfdir
 
 	toinvalidate := map[*BigFile]SetI64{} // {} file -> set(#blk)
 
@@ -570,11 +574,21 @@ func (r *Root) zhandle1(zevent zodb.WatchEvent) {
 			// since we write-locked head.zconnMu and bindZFile is
 			// run when loading objects - thus when head.zconnMu is
 			// read-locked.
+			//
+			// bfdir locking: similarly not needed, since we are
+			// exclusively holding head lock.
 			for zfile, objBlk := range obj.blkBoundTo() {
-				blkmap, ok := toinvalidate[zfile]
+				file, ok := bfdir.tab[zfile.POid()]
+				if !ok {
+					// even though zfile is in ZODB cache, the
+					// filesystem already forgot about this file.
+					continue
+				}
+
+				blkmap, ok := toinvalidate[file]
 				if !ok {
 					blkmap = SetI64{}
-					toinvalidate[zfile] = blkmap
+					toinvalidate[file] = blkmap
 				}
 				blkmap.Update(objBlk)
 			}
@@ -791,22 +805,27 @@ func (root *Root) mkdir(name string, fctx *fuse.Context) (_ *nodefs.Inode, err e
 		return nil, syscall.EEXIST
 	}
 
+	// XXX -> newHead()
 	revDir := &Head{
 		Node:  nodefs.NewDefaultNode(),
 		rev:   rev,
 		zconn: zconnRev,
 	}
 
+	bfdir := &BigFileDir{
+		Node: nodefs.NewDefaultNode(),
+		head: revDir,
+		tab:  make(map[zodb.Oid]*BigFile),
+	}
+	revDir.bfdir = bfdir
+
 	root.revTab[rev] = revDir
 	root.revMu.Unlock()
 
 	// mkdir takes filesystem treeLock - do it outside revMu.
 	mkdir(root, name, revDir)
-	mkdir(revDir, "bigfile", &BigFileDir{
-		Node: nodefs.NewDefaultNode(),
-		head: revDir,
-		tab:  make(map[zodb.Oid]*BigFile),
-	})
+	mkdir(revDir, "bigfile", bfdir)
+	// XXX + "at"
 
 	return revDir.Inode(), nil
 }
@@ -1144,11 +1163,18 @@ func main() {
 	zhead.Cache().SetControl(&zodbCacheControl{})	// XXX +locking?
 
 	// mount root + head/
+	// XXX -> newHead()
 	head := &Head{
 		Node:  nodefs.NewDefaultNode(),
 		rev:   0,
 		zconn: zhead,
 	}
+	bfdir := &BigFileDir{
+		Node:  nodefs.NewDefaultNode(),
+		head:  head,
+		tab:   make(map[zodb.Oid]*BigFile),
+	}
+	head.bfdir = bfdir
 
 	root := &Root{
 		Node:   nodefs.NewDefaultNode(),
@@ -1183,11 +1209,7 @@ func main() {
 	// add entries to /
 	mkfile(root, ".wcfs", NewStaticFile([]byte(zurl)))
 	mkdir(root, "head", head)
-	mkdir(head, "bigfile", &BigFileDir{
-		Node:  nodefs.NewDefaultNode(),
-		head:  head,
-		tab:   make(map[zodb.Oid]*BigFile),
-	})
+	mkdir(head, "bigfile", bfdir)
 	mkfile(head, "at", NewSmallFile(head.readAt))   // TODO mtime(at) = tidtime(at)
 
 	// TODO handle autoexit