Index: head/bin/dd/tests/dd2_test.sh
===================================================================
--- head/bin/dd/tests/dd2_test.sh	(revision 319550)
+++ head/bin/dd/tests/dd2_test.sh	(revision 319551)
@@ -1,54 +1,69 @@
 #
 # Copyright (c) 2017 Spectra Logic Corporation
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
 # are met:
 # 1. Redistributions of source code must retain the above copyright
 #    notice, this list of conditions and the following disclaimer.
 # 2. Redistributions in binary form must reproduce the above copyright
 #    notice, this list of conditions and the following disclaimer in the
 #    documentation and/or other materials provided with the distribution.
 #
 # THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 # ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 # TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 # PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 # BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 #
 # $FreeBSD$
 
 
-atf_test_case seek_overflow
-seek_overflow_head()
+atf_test_case max_seek
+max_seek_head()
 {
-	atf_set "descr" "dd(1) should reject too-large seek values"
+	atf_set "descr" "dd(1) can seek by the maximum amount"
 }
-seek_overflow_body()
+max_seek_body()
 {
-	atf_expect_fail "fails with 'dd: truncating f.out: File too large' - bug 219757"
+	case `df -T . | tail -n 1 | cut -wf 2` in
+		"ufs")
+			atf_skip "UFS's maximum file size is too small";;
+		"zfs") ;; # ZFS is fine
+		"tmpfs")
+			atf_skip "tmpfs can't create arbitrarily large spare files";;
+		*) atf_skip "Unknown file system";;
+	esac
 
 	touch f.in
-	# Positive tests
 	seek=`echo "2^63 / 4096 - 1" | bc`
 	atf_check -s exit:0 -e ignore dd if=f.in of=f.out bs=4096 seek=$seek
+}
 
-	# Negative tests
+atf_test_case seek_overflow
+seek_overflow_head()
+{
+	atf_set "descr" "dd(1) should reject too-large seek values"
+}
+seek_overflow_body()
+{
+	touch f.in
 	seek=`echo "2^63 / 4096" | bc`
 	atf_check -s not-exit:0 -e match:"seek offsets cannot be larger than" \
 		dd if=f.in of=f.out bs=4096 seek=$seek
 	atf_check -s not-exit:0 -e match:"seek offsets cannot be larger than" \
 		dd if=f.in of=f.out bs=4096 seek=-1
 }
 
 atf_init_test_cases()
 {
-        atf_add_test_case seek_overflow
+	atf_add_test_case max_seek
+	atf_add_test_case seek_overflow
 }