xfstests: 226: have xfs_io use bigger buffers

[Alex Elder <aelder@xxxxxxx>]

By default xfs_io uses a buffer size of 4096 bytes.  On test 226,
the result is that the test runs much slower (at least an order
of magnitude) than it needs to.

Add a flag to the "pwrite" command sent to xfs_io so it uses
larger buffers, thereby speeding things up considerably.

Signed-off-by: Alex Elder <aelder@xxxxxxx>

---
 226 |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

Index: b/226
===================================================================
--- a/226
+++ b/226
@@ -49,10 +49,14 @@ _scratch_mount
 
 loops=16
 
+# Buffer size argument supplied to xfs_io "pwrite" command
+buffer="-b $(expr 512 \* 1024)"
+
 echo "--> $loops buffered 64m writes in a loop"
 for I in `seq 1 $loops`; do
        echo -n "$I "
-       xfs_io -F -f -c 'pwrite 0 64m' $SCRATCH_MNT/test >> $seq.full
+       xfs_io -F -f \
+               -c "pwrite ${buffer} 0 64m" $SCRATCH_MNT/test >> $seq.full
        rm -f $SCRATCH_MNT/test
 done
 
@@ -63,7 +67,8 @@ _scratch_mount
 echo "--> $loops direct 64m writes in a loop"
 for I in `seq 1 $loops`; do
        echo -n "$I "
-       xfs_io -F -f -d -c 'pwrite 0 64m' $SCRATCH_MNT/test >> $seq.full
+       xfs_io -F -f -d \
+               -c "pwrite ${buffer} 0 64m" $SCRATCH_MNT/test >> $seq.full
        rm -f $SCRATCH_MNT/test 
 done