generic/192: fix spurious timeout

I have a theory that when the nfs server that hosts the root fs for my
testing VMs gets backed up, it can take a while for path resolution and
loading of echo, cat, or tee to finish.  That delays the test enough to
result in:

  --- /tmp/fstests/tests/generic/192.out	2023-11-29 15:40:52.715517458 -0800
  +++ /var/tmp/fstests/generic/192.out.bad	2023-12-15 21:28:02.860000000 -0800
  @@ -1,5 +1,6 @@
   QA output created by 192
   sleep for 5 seconds
   test
  -delta1 is in range
  +delta1 has value of 12
  +delta1 is NOT in range 5 .. 7
   delta2 is in range

Therefore, invoke all these utilities with --help before the critical
section to make sure they're all in memory.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Zorro Lang <zlang@kernel.org>

diff --git a/tests/generic/192 b/tests/generic/192
index 0d3cd03b4bf3639a05b12106bdfe94a691db59b0..28254866357bd636fa7d5ffc1f075d7013bec781 100755 (executable)
--- a/tests/generic/192
+++ b/tests/generic/192
@@ -29,17 +29,27 @@ delay=5
 testfile=$TEST_DIR/testfile
 rm -f $testfile
 
+# Preload every binary used between sampling time1 and time2 so that loading
+# them has minimal overhead even if the root fs is hosted over a slow network.
+# Also don't put pipe and tee creation in that critical section.
+for i in echo stat sleep cat; do
+       $i --help &>/dev/null
+done
+
 echo test >$testfile
-time1=`_access_time $testfile | tee -a $seqres.full`
+time1=`_access_time $testfile`
+echo $time1 >> $seqres.full
 
 echo "sleep for $delay seconds"
 sleep $delay # sleep to allow time to move on for access
 cat $testfile
-time2=`_access_time $testfile | tee -a $seqres.full`
+time2=`_access_time $testfile`
+echo $time2 >> $seqres.full
 
 cd /
 _test_cycle_mount
-time3=`_access_time $testfile | tee -a $seqres.full`
+time3=`_access_time $testfile`
+echo $time3 >> $seqres.full
 
 delta1=`expr $time2 - $time1`
 delta2=`expr $time3 - $time1`