tests: try using truncate command before falling back to using dd

On the GNU Hurd, dd seems to be buggy and hangs if seeking beyond 4G.
Fortunately the GNU Hurd does have the truncate command, which does
work correctly.  So try using the truncate command first, and fall
back to using dd only if the truncate command doesn't work.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/tests/scripts/resize_test b/tests/scripts/resize_test
index 3c5e260..fc9d1c2 100755 (executable)
--- a/tests/scripts/resize_test
+++ b/tests/scripts/resize_test
@@ -1,11 +1,13 @@
 #!/bin/sh
 
-# old distros are missing "truncate", emulate it with "dd"
-truncate()
+# old distros are missing "truncate", emulate it with "dd" if necessary
+do_truncate()
 {
        [ "$1" = "-s" ] && size=$2 && shift 2
 
-       dd if=/dev/zero of=$1 bs=1 count=0 seek=$size >> $LOG 2>&1
+       if ! truncate -s $size $1 >> $LOG 2>&1 ; then
+               dd if=/dev/zero of=$1 bs=1 count=0 seek=$size >> $LOG 2>&1
+       fi
 }
 
 resize_test () {
@@ -17,14 +19,14 @@ touch $TMPFILE
 
 # Verify that the $TMP filesystem handles $SIZE_2 sparse files.
 # If that fails, try the local filesystem instead.
-if truncate -s $SIZE_2 $TMPFILE 2> /dev/null; then
+if do_truncate -s $SIZE_2 $TMPFILE 2> /dev/null; then
        echo "using $TMPFILE" >> $LOG
 else
        rm $TMPFILE
        export TMPFILE=$(mktemp ./$test_name.tmp.XXXXXX)
        touch $TMPFILE
        echo "using $TMPFILE" >> $LOG
-       if ! truncate -s $SIZE_2 $TMPFILE >> $LOG 2>&1; then
+       if ! do_truncate -s $SIZE_2 $TMPFILE >> $LOG 2>&1; then
                rm $TMPFILE
                return 111
        fi