.

wcfs/client/wcfs.cpp

@@ -641,7 +641,7 @@ pair<FileH, error> _Conn::open(zodb::Oid foid) {
         return make_pair(f, nil);
     }
 
-    // create in-flight-opening FileH entry and perform open with wconn._mu released
+    // create "opening" FileH entry and perform open with wconn._mu released
     // NOTE wconn._atMu.R is still held because FileH._open relies on wconn.at being stable.
     f = adoptref(new _FileH());
     f->wconn      = newref(&wconn);
@@ -660,7 +660,10 @@ pair<FileH, error> _Conn::open(zodb::Oid foid) {
         if (!retok) {
             wconn._mu.Lock();
             // don't care about f->_nopen-- since f is not returned anywhere
-            // XXX assert filehTab[foid] == f
+            if (wconn._filehTab.get(foid) != f) {
+                wconn._mu.Unlock();
+                panic("BUG: wconn.open: wconn.filehTab[foid] mutated while file open was in progress");
+            }
             wconn._filehTab.erase(foid);
             wconn._mu.Unlock();
         }
@@ -745,7 +748,7 @@ error _FileH::close() {
 
     // decref open count; do real close only when last open goes away.
     if (fileh._nopen <= 0)
-        panic("BUG: fileh._nopen <= 0");
+        panic("BUG: fileh.close: fileh._nopen <= 0");
     fileh._nopen--;
     if (fileh._nopen > 0)
         return nil;