.

wcfs/internal/_wcfs.pxd

@@ -99,10 +99,12 @@ cdef extern from "wcfs/internal/wcfs.h" namespace "wcfs" nogil:
         error               resync      "_ptr()->resync"    (Tid at)
 
     cppclass _FileH:
+        size_t               blksize
         pair[Mapping, error] mmap(int64_t blk_start, int64_t blk_len)   # `VMA *vma=nil` not exposed
 
     cppclass FileH (refptr[_FileH]):
         # FileH.X = FileH->X in C++
+        size_t               blksize    "_ptr()->blksize"
         pair[Mapping, error] mmap       "_ptr()->mmap"      (int64_t blk_start, int64_t blk_len)
 
     cppclass _Mapping:

wcfs/internal/_wcfs.pyx

@@ -113,6 +113,10 @@ cdef class PyFileH:
         pywmmap.fileh = pywfileh
         return pywmmap
 
+    property blksize:
+        def __get__(PyFileH pywfileh):
+            return pywfileh.wfileh.blksize
+
     # XXX for tests
     property pinned:
         def __get__(PyFileH pywfileh):