.

wcfs/wcfs.go

@@ -421,6 +421,8 @@ package main
 //			RLock by read
 // ...
 //
+// zheadMu.W  |  zheadMu.R + bfdir.fileMu
+//
 // WatchLink.byfileMu	> Watch.mu
 // BigFile.watchMu      > Watch.mu
 
@@ -523,7 +525,7 @@ type BigFileDir struct {
 	head *Head // parent head/ or @<rev>/
 
 	// {} oid -> <bigfileX>
-	fileMu  sync.Mutex	// XXX doc zheadMu.W  |  ...	?
+	fileMu  sync.Mutex            // zheadMu.W  |  zheadMu.R + fileMu
 	fileTab map[zodb.Oid]*BigFile
 
 	// δ tail of tracked BTree nodes of all BigFiles + -> which file