ZFS: fix the redundancy tests

* Fix force_sync_path, which ensures that a file is fully flushed to disk.
  Apparently "zpool history"'s performance has improved, but exporting and
  importing the pool still works.
* Fix file_dva by using undocumented zdb syntax to clarify that we're
  interested in the pool's root file system, not the pool itself. This
  should also fix the zpool_clear_001_pos test.
* Remove a redundant cleanup step

MFC after:	2 weeks
Sponsored by:	Axcient
Differential Revision:	https://reviews.freebsd.org/D21901

tests/sys/cddl/zfs/include/libtest.kshlib

@@ -2676,8 +2676,7 @@ function gen_dataset_name
 #
 # Ensure that a given path has been synced, not just ZIL committed.
 #
-# XXX The implementation currently requires calling 'zpool history'.  On
-#     FreeBSD, the sync(8) command (via $SYNC) calls zfs_sync() which just
+# XXX On FreeBSD, the sync(8) command (via $SYNC) calls zfs_sync() which just
 #     does a zil_commit(), as opposed to a txg_wait_synced().  For things that
 #     require writing to their final destination (e.g. for intentional
 #     corruption purposes), zil_commit() is not good enough.
@@ -2686,10 +2685,8 @@ function force_sync_path # path
 {
 	typeset path="$1"
 
-	zfspath=$($DF $path 2>/dev/null | tail -1 | cut -d" " -f1 | cut -d/ -f1)
-	[ -z "$zfspath" ] && return false
-	log_note "Force syncing ${zfspath} for ${path} ..."
-	$ZPOOL history $zfspath >/dev/null 2>&1
+	log_must $ZPOOL export $TESTPOOL
+	log_must $ZPOOL import -d $path $TESTPOOL
 }
 
 #
@@ -3326,7 +3323,7 @@ function file_dva # dataset filepath [level] [offset] [dva_num]
 	# The inner match is for 'DVA[0]=<0:1b412600:200>', in which the
 	# text surrounding the actual DVA is a fixed size with 8 characters
 	# before it and 1 after.
-	$ZDB -P -vvvvv $dataset $inode | \
+	$ZDB -P -vvvvv "$dataset/" $inode | \
 	    $AWK -v level=${level} -v dva_num=${dva_num} '
 		BEGIN { stage = 0; }
 		(stage == 0) && ($1=="Object") { stage = 1; next; }

tests/sys/cddl/zfs/tests/redundancy/redundancy.kshlib

@@ -98,7 +98,7 @@ function setup_test_env
 
 	typeset file=$TESTDIR/file
 	log_must $FILE_WRITE -o create -f $file -b $BLOCKSZ -c $NUM_WRITES
-	log_must force_sync_path $TESTDIR
+	force_sync_path $BASEDIR
 	record_data $TESTPOOL $PRE_RECORD_FILE
 }
 
@@ -142,7 +142,7 @@ function sync_pool #pool
 {
 	typeset pool=$1
 
-	log_must force_sync_path $pool
+	force_sync_path $BASEDIR
 
 	# If the OS has detected corruption on the pool, it will have
 	# automatically initiated a scrub.  In that case, our "zpool scrub"

tests/sys/cddl/zfs/tests/redundancy/redundancy_001_pos.ksh

@@ -62,7 +62,6 @@
 verify_runnable "global"
 
 log_assert "Verify raidz pool can withstand one device is failing."
-log_onexit cleanup
 
 for cnt in 3 2; do
 	setup_test_env $TESTPOOL raidz $cnt