Index: projects/zfsd/head/tests/sys/cddl/zfs/tests/snapshot/snapshot_019_pos.ksh
===================================================================
--- projects/zfsd/head/tests/sys/cddl/zfs/tests/snapshot/snapshot_019_pos.ksh	(revision 292300)
+++ projects/zfsd/head/tests/sys/cddl/zfs/tests/snapshot/snapshot_019_pos.ksh	(revision 292301)
@@ -1,91 +1,117 @@
 #! /usr/local/bin/ksh93 -p
 #
 # CDDL HEADER START
 #
 # The contents of this file are subject to the terms of the
 # Common Development and Distribution License (the "License").
 # You may not use this file except in compliance with the License.
 #
 # You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 # or http://www.opensolaris.org/os/licensing.
 # See the License for the specific language governing permissions
 # and limitations under the License.
 #
 # When distributing Covered Code, include this CDDL HEADER in each
 # file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 # If applicable, add the following below this CDDL HEADER, with the
 # fields enclosed by brackets "[]" replaced with your own identifying
 # information: Portions Copyright [yyyy] [name of copyright owner]
 #
 # CDDL HEADER END
 #
 
 #
 # Copyright 2013 Spectra Logic.  All rights reserved.
 # Use is subject to license terms.
 #
 #
 . $STF_SUITE/include/libtest.kshlib
 
 ################################################################################
 #
 # __stc_assertion_start
 #
 # ID: snapshot_019_pos
 #
 # DESCRIPTION:
 #	Accessing snapshots and unmounting them in parallel does not panic.
 #	FreeBSD PR kern/184677
 #
 # STRATEGY:
 #	1. Create a dataset
 #	2. Set the snapdir property to visible
 #	3. Do the following in parallel
 #	   a. Repeatedly access the snapshot
 #	   b. Repeatedly unmount the snapshot
 #	4. Verify that the system does not panic
 #
 # TESTABILITY: explicit
 #
 # TEST_AUTOMATION_LEVEL: automated
 #
 # CODING_STATUS: COMPLETED (2013-12-23)
 #
 # __stc_assertion_end
 #
 ################################################################################
 
 verify_runnable "both"
 
+KILL_SWITCH=${PWD}/kill_switch
+
 function stat_snapshot
 {
-	#cd $TESTDIR/$SNAPROOT
-	while true; do
-		stat "$SNAPDIR" > /dev/null
+	while [ ! -f ${KILL_SWITCH} ]; do
+		cd $SNAPDIR # Exercise forced unmount
+		stat "$SNAPDIR" > /dev/null 2>&1
 	done
 }
 
+function ls_snapshot
+{
+	# Pre-generate the argument list.
+	ls_args=""
+	for ((num=0; $num<100; num=$num+1)); do
+		ls_args="$ls_args $SNAPDIR/.."
+	done
+
+	while [ ! -f ${KILL_SWITCH} ]; do
+		ls $ls_args >/dev/null 2>&1
+	done
+}
+
 log_assert "Accessing snapshots and unmounting them in parallel does not panic"
 
 log_must dataset_setprop $TESTPOOL "snapdir" "visible"
 
 # Take snapshots
 log_must $ZFS snapshot "$TESTPOOL/$TESTFS@$TESTSNAP"
 
 # Repeatedly access the snapshot directory
 stat_snapshot &
 stat_pid="$!"
+ls_snapshot &
+ls_pid="$!"
 
 # Repeatedly unmount the snapshot directory
 for ((i=0; $i<100; i=$i+1)); do
-	umount "$SNAPDIR"
-	echo $i
-	# Sleep just long enough for stat() to have a chance at remounting.
+	umount "$SNAPDIR" >/dev/null 2>&1
+	log_note "$i non-forced done"
+	# Sleep just long enough for the other "threads" to remount.
 	sleep 0.1
+	umount -f "$SNAPDIR" >/dev/null 2>&1
+	log_note "$i forced done"
+	sleep 0.1
 done
 
-# Cleanup
-log_must kill "$stat_pid"
+# Kill the other "threads" and wait for them to die.
+touch $KILL_SWITCH
+log_note "Waiting for all child processes to die..."
+wait
 
-# The only failure scenario is panic.  If we got here, then we passed
+# Test that no reference leaks occurred and we can cleanup without forcing.
+log_must $ZFS unmount $TESTPOOL/$TESTFS
+log_must $ZFS destroy -r $TESTPOOL/$TESTFS
+
+# If we get here, we managed to not panic, deadlock, or leak references.
 log_pass