add write tester script

tools/run-writetest.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+
+dir=/tmp
+numfiles=128
+nocache=
+sync=
+filesize=`expr 10 \* 1048576`
+
+while [ $# -gt 1 ] ; do
+    case $1 in
+	-d) dir=$2; shift; shift ;;
+	-n) numfiles=$2; shift; shift ;;
+	-D) nocache="-D"; shift ;;
+        -s) sync="-s"; shift;;
+        -S) filesize=$2; shift; shift ;;
+        *) break ;;
+    esac
+done
+
+rm -r $dir/sftest
+
+for bs in $@ ; do
+    echo "Blocksize $bs"
+    ./sftest $sync $nocache -b $bs -q -d $dir -S $filesize
+    rm -r $dir/sftest
+done