[RFC 5/9] selftests: block_seek_hole: add dm-zero test

[Stefan Hajnoczi <stefanha@redhat.com>]

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 .../selftests/block_seek_hole/Makefile        |  2 +-
 .../testing/selftests/block_seek_hole/config  |  2 ++
 .../selftests/block_seek_hole/dm_zero.sh      | 31 +++++++++++++++++++
 3 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100755 tools/testing/selftests/block_seek_hole/dm_zero.sh

diff --git a/tools/testing/selftests/block_seek_hole/Makefile b/tools/testing/selftests/block_seek_hole/Makefile
index 3f4bbd52db29f..1bd9e748b2acc 100644
--- a/tools/testing/selftests/block_seek_hole/Makefile
+++ b/tools/testing/selftests/block_seek_hole/Makefile
@@ -3,7 +3,7 @@ PY3 = $(shell which python3 2>/dev/null)
 
 ifneq ($(PY3),)
 
-TEST_PROGS := test.py
+TEST_PROGS := test.py dm_zero.sh
 
 include ../lib.mk
 
diff --git a/tools/testing/selftests/block_seek_hole/config b/tools/testing/selftests/block_seek_hole/config
index 72437e0c0fc1c..bfd59f1d98769 100644
--- a/tools/testing/selftests/block_seek_hole/config
+++ b/tools/testing/selftests/block_seek_hole/config
@@ -1 +1,3 @@
 CONFIG_BLK_DEV_LOOP=m
+CONFIG_BLK_DEV_DM=m
+CONFIG_DM_ZERO=m
diff --git a/tools/testing/selftests/block_seek_hole/dm_zero.sh b/tools/testing/selftests/block_seek_hole/dm_zero.sh
new file mode 100755
index 0000000000000..20836a566fcc8
--- /dev/null
+++ b/tools/testing/selftests/block_seek_hole/dm_zero.sh
@@ -0,0 +1,31 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# dm_zero.sh
+#
+# Test that dm-zero reports data because it does not have a custom
+# SEEK_HOLE/SEEK_DATA implementation.
+
+set -e
+
+dev_name=test-$$
+size=$((1024 * 1024 * 1024 / 512)) # 1 GB
+
+cleanup() {
+	dmsetup remove $dev_name
+}
+trap cleanup EXIT
+
+dmsetup create $dev_name --table "0 $size zero"
+
+output=$(./map_holes.py /dev/mapper/$dev_name)
+expected='TYPE START END SIZE
+DATA 0 1073741824 1073741824'
+
+if [ "$output" != "$expected" ]; then
+	echo 'FAIL expected:'
+	echo "$expected"
+	echo 'Does not match device output:'
+	echo "$output"
+	exit 1
+fi
-- 
2.44.0