.

bigfile/file_zodb.py

@@ -477,6 +477,12 @@ class ZBigFile(LivePersistent):
         LivePersistent.__init__(self)
         self.__setstate__((blksize, LOBTree()))     # NOTE L enough for blk_t
 
+        # TODO use custom class for .blktab with adjusted bucket size, simething like
+        # class xLOBTree(LOBTree):
+        #   __slots__ = ()
+        #   max_leaf_size       = ...   # BTree's default =  60
+        #   max_internal_size   = ...   # BTree's default = 500
+
 
     # state is (.blksize, .blktab)
     def __getstate__(self):

wcfs/wcfs.go

@@ -412,6 +412,11 @@ package main
 // δF    - change in File*s* space
 // δfile - change in File(1) space
 
+// XXX describe locking
+//
+// head.zconnMu		write by handleδZ; read by read
+// ...
+
 import (
 	"bufio"
 	"context"
@@ -1362,6 +1367,11 @@ func (wlink *WatchLink) setupWatch(ctx context.Context, foid zodb.Oid, at zodb.T
 		return fmt.Errorf("at is too far away back from head/at")
 	}
 
+	// XXX register w to f early, so that READs going in parallel to us
+	// preparing and processing initial pins, also sends pin for read
+	// blocks. If we don't we can miss to send pin for a freshly read which
+	// could have revision > w.at .
+
 	toPin := map[int64]zodb.Tid{} // blk -> @rev
 
 	// XXX locking ok?
@@ -1393,8 +1403,6 @@ func (wlink *WatchLink) setupWatch(ctx context.Context, foid zodb.Oid, at zodb.T
 		panic(err)	// XXX
 	}
 
-	// XXX register w to f (here ?)
-
 	return nil
 }
 

wcfs/wcfs_test.py

@@ -651,6 +651,9 @@ def test_wcfs():
     # XXX ZBlk copied from blk1 -> blk2 ; for the same file and for file1 -> file2
     # XXX ZBlk moved  from blk1 -> blk2 ; for the same file and for file1 -> file2
 
+    # XXX read file[blk]=hole; then file[blk]=zblk - must be invalidated and
+    # setupWatch must send pins.
+
 
 
 def test_wcfs_invproto():

wcfs/δftail.go

@@ -192,6 +192,10 @@ func (δFtail *ΔFtail) SliceByFileRev(file *BigFile, lo, hi zodb.Tid) /*readonl
 	// FIXME stub: assumes blktab topology does not change.
 	//       takes only ZBlk history into account.
 	var vδfile []Δfile
+	for _, δZ := range vδZ {
+		for _, oid := range δZ.Changev {
+		}
+	}
 
 /*
 	// XXX activate zfile?