add cache function
diff --git a/include/venti.h b/include/venti.h
index 0ea07c4..889f86d 100644
--- a/include/venti.h
+++ b/include/venti.h
@@ -387,6 +387,7 @@
VtBlock *vtcachelocal(VtCache*, u32int addr, int type);
VtBlock *vtcacheglobal(VtCache*, uchar[VtScoreSize], int type);
VtBlock *vtcacheallocblock(VtCache*, int type);
+void vtcachesetwrite(VtCache*, int(*)(VtConn*,uchar[VtScoreSize],uint,uchar*,int));
void vtblockput(VtBlock*);
u32int vtcacheblocksize(VtCache*);
int vtblockwrite(VtBlock*);