Fix leak in writer_buffer cache:
http://squashfs.cvs.sourceforge.net/viewvc/squashfs/squashfs/squashfs-tools/mksquashfs.c?r1=1.101&r2=1.102

--- squashfs-tools/mksquashfs.c
+++ squashfs-tools/mksquashfs.c
@@ -1496,6 +1496,8 @@
 	else
 		read_destination(fd, start_block, size, buffer->data);
 
+	cache_block_put(compressed_buffer);
+
 	return buffer;
 }