.

bigfile/file_zodb.cpp

@@ -41,12 +41,13 @@ static void* zfile_mmap_setup_read(VMA *vma, BigFile *file, blk_t blk, size_t bl
     if (err != nil)
         panic("TODO");  // XXX
 
+#if 0 // done by wcfs.cpp
     mmap->incref(); // vma->mmap_overlay_server is keeping ref to mmap
     vma->mmap_overlay_server = mmap._ptr();
 
-    // XXX here? -> in fileh->mmap? don't set at all here?
     vma->addr_start = (uintptr_t)mmap->mem_start;
     vma->addr_stop  = (uintptr_t)mmap->mem_stop;
+#endif
 
     return (void*)vma->addr_start;  // XXX kill if we set vma->addr_*
 }

wcfs/client/wcfs.cpp

@@ -450,14 +450,19 @@ pair<Mapping, error> _FileH::mmap(int64_t blk_start, int64_t blk_len, VMA *vma)
             return make_pair(nil, E(err));
     }
 
-    f._mmaps.push_back(mmap);   // TODO keep f._mmaps ↑blk_start
-
-    // XXX vvv kill from here completely?
-    // (zfile_mmap_setup_read does vma->mmap_overlay_server = mmap + incref itself)
     if (vma != NULL) {
-        vma->mmap_overlay_server = mmap._ptr(); // XXX +giveref
+        if (vma->mmap_overlay_server != nil)
+            panic("vma is already associated with overlay server");
+        if (!(vma->addr_start == 0 && vma->addr_stop == 0))
+            panic("vma already covers !nil virtual memory area");
+        mmap->incref(); // vma->mmap_overlay_server is keeping ref to mmap
+        vma->mmap_overlay_server = mmap._ptr();
+        vma->addr_start = (uintptr_t)mmap->mem_start;
+        vma->addr_stop  = (uintptr_t)mmap->mem_stop;
     }
 
+    f._mmaps.push_back(mmap);   // TODO keep f._mmaps ↑blk_start
+
     retok = true;
     return make_pair(mmap, nil);
 }

wcfs/client/wcfs.h

@@ -33,7 +33,7 @@
 // views are a bit outdated, but close to head, which means that in practice
 // the kernel cache for /head/bigfile/* is being used almost 100% of the time.
 //
-// A mapping for bigfile X @at is built from OS-level memory mappings of
+// A mapping for bigfile X@at is built from OS-level memory mappings of
 // on-WCFS files as follows:
 //
 //                                           ___        /@revA/bigfile/X