generic/475: fix confusing comment

The comment about the dmerror switcheroo is hard to understand and
wrong.  Fix both problems by rewriting it.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

diff --git a/tests/generic/475 b/tests/generic/475
index e31f1251c5cba636ef4a7f6d4eb6f2f5224407a5..450722784142b6dd19d6a56121f052f642c3ccb5 100755 (executable)
--- a/tests/generic/475
+++ b/tests/generic/475
@@ -73,9 +73,11 @@ for i in $(seq 1 $((50 * TIME_FACTOR)) ); do
        # recovery
        sleep $((RANDOM % 3))
 
-       # Loading error table without "--nolockfs" option. Because "--nolockfs"
-       # won't freeze fs, then some running I/Os may cause XFS to shutdown
-       # prematurely. That's not what we want to test.
+       # This test aims to simulate sudden disk failure, which means that we
+       # do not want to quiesce the filesystem or otherwise give it a chance
+       # to flush its logs.  Therefore we want to call dmsetup with the
+       # --nolockfs parameter; to make this happen we must call the load
+       # error table helper *without* 'lockfs'.
        _dmerror_load_error_table
 
        ps -e | grep fsstress > /dev/null 2>&1