Index: programs/mythbackend/mainserver.cpp
===================================================================
--- programs/mythbackend/mainserver.cpp	(revision 10950)
+++ programs/mythbackend/mainserver.cpp	(working copy)
@@ -1619,7 +1619,8 @@
     // Get the on disk file size and disk block size.
     struct stat buf;
     fstat(fd, &buf);
-    size_t fsize = buf.st_blksize * buf.st_blocks;
+    size_t fsize =
+        ((buf.st_size + buf.st_blksize - 1) / buf.st_blksize) * buf.st_blksize;
 
     // Round truncate increment up to a blocksize, w/min of 1 block.
     increment = ((increment / buf.st_blksize) + 1) * buf.st_blksize;