.

wcfs/__init__.py

@@ -156,7 +156,7 @@ def close(wconn):
 
     # close all files - both that have no mappings and that still have opened mappings.
     # XXX after file is closed mappings continue to survive, but we can no
-    # longer maintin consisten view.
+    # longer maintain consistent view.
     with wconn._filemu:
         for f in wconn._filetab.values():
             f.headf.close()
@@ -249,17 +249,31 @@ def _pin1(wconn, req):
 def resync(wconn, at):
     # XXX locking
 
-    for foid in wconn._filetab:
+    for foid, f in wconn._filetab.items():
         # XXX if file has no mappings and was not used during whole prev
         # cycle - forget and stop watching it
+
+        # update f.headfsize and remmap to head/f zero regions that are now covered by head/f
+        _ = os.fstat(f.headf.fileno())
+        assert f.blksize == _.st_blksize    # blksize must not change
+        headfsize = _.st_size
+        assert f.headfsize <= headfsize     # head/file size ↑=
+        assert headfsize % f.blksize == 0
+        for mmap in f.mmaps:
+            memunzero = mmap.mem[f.headfsize - mmap.blk_start*f.blksize :
+                                 headfsize   - mmap.blk_start*f.blksize]
+            if len(memunzero) > 0:
+                mm.map_into_ro(memunzero, f.headf.fileno(), f.headfsize)
+
+        f.headfsize = headfsize
+
+
         _ = wconn._wlink.sendReq(context.background(), b"watch %s @%s" % (h(foid), h(at)))
         if _ != "ok":
             # XXX unregister f from _filetab
             # XXX vvv -> errctx?
             raise RuntimeError("resync @%s -> @%s: f<%s>: %s" % (h(wconn.at), h(at), h(foid), _))
 
-        # XXX update f.headfsize
-        # XXX remmap appended data after old f.headfsize
 
     wconn.at = at
 
@@ -282,6 +296,7 @@ def mmap(wconn, foid, blk_start, blk_len): # -> Mapping
             _ = os.fstat(f.headf.fileno())
             f.blksize   = _.st_blksize
             f.headfsize = _.st_size
+            assert f.headfsize % f.blksize == 0
 
             wconn._filetab[foid] = f
 
@@ -323,7 +338,13 @@ def mmap(wconn, foid, blk_start, blk_len): # -> Mapping
 def _remmapblk(mmap, blk, at):
     assert mmap.blk_start <= blk < mmap.blk_stop
     f = mmap.file
+    blkmem = mmap.mem[(blk-mmap.blk_start)*f.blksize:][:f.blksize]
     if at is None:
+        # head/file[blk >= size] -> Z
+        if blk*f.blksize >= f.headfsize:
+            mm.map_zero_into(blkmem)
+            return
+        # head/file[blk < size]  -> use the file
         fsfile = f.headf
     else:
         # TODO share @rev fd until wconn is resynced?
@@ -331,9 +352,7 @@ def _remmapblk(mmap, blk, at):
         defer(fsfile.close)
         assert os.fstat(fsfile.fileno()).st_blksize == f.blksize  # FIXME assert
 
-    mm.map_into_ro(
-            mmap.mem[(blk-mmap.blk_start)*f.blksize:][:f.blksize],
-            fsfile.fileno(), blk*f.blksize)
+    mm.map_into_ro(blkmem, fsfile.fileno(), blk*f.blksize)
 
 
 # remmap_blk remmaps file[blk] in its place again.
@@ -758,7 +777,7 @@ def join(zurl, autostart=_default_autostart()): # -> WCFS
 # _start starts wcfs server for ZODB @ zurl.
 #
 # optv can be optionally given to pass flags to wcfs.
-# called under _wcmu
+# called under _wcmu.
 def _start(zurl, *optv):    # -> WCFS
     mntpt = _mntpt_4zurl(zurl)
     log.info("wcfs: starting for %s ...", zurl)