[PATCH for-5.1 2/2] iotests/028: Add test for cross-base-EOF reads

[Max Reitz <mreitz@redhat.com>]

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 tests/qemu-iotests/028     | 19 +++++++++++++++++++
 tests/qemu-iotests/028.out | 11 +++++++++++
 2 files changed, 30 insertions(+)

diff --git a/tests/qemu-iotests/028 b/tests/qemu-iotests/028
index 5d043cef92..6dd3ae09a3 100755
--- a/tests/qemu-iotests/028
+++ b/tests/qemu-iotests/028
@@ -142,6 +142,25 @@ TEST_IMG="${TEST_IMG}.copy" io_zero readv $(( offset + 32 * 1024 )) 512 1024 32
 
 _check_test_img
 
+echo
+echo '=== Reading across backing EOF in one operation ==='
+echo
+
+# Use a cluster boundary as the base end here
+base_size=$((3 * 1024 * 1024 * 1024))
+
+TEST_IMG="$TEST_IMG.base" _make_test_img $base_size
+_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $image_size
+
+# Write 16 times 42 at the end of the base image
+$QEMU_IO -c "write -P 42 $((base_size - 16)) 16" "$TEST_IMG.base" \
+    | _filter_qemu_io
+
+# Read 32 bytes across the base EOF from the top;
+# should be 16 times 0x2a, then 16 times 0x00
+$QEMU_IO -c "read -v $((base_size - 16)) 32" "$TEST_IMG" \
+    | _filter_qemu_io
+
 # success, all done
 echo "*** done"
 rm -f $seq.full
diff --git a/tests/qemu-iotests/028.out b/tests/qemu-iotests/028.out
index 12f82c6a6c..5a68de5c46 100644
--- a/tests/qemu-iotests/028.out
+++ b/tests/qemu-iotests/028.out
@@ -730,4 +730,15 @@ read 512/512 bytes at offset 3221257728
 read 512/512 bytes at offset 3221258752
 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 No errors were found on the image.
+
+=== Reading across backing EOF in one operation ===
+
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=3221225472
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4294968832 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
+wrote 16/16 bytes at offset 3221225456
+16 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+bffffff0:  2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a  ................
+c0000000:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
+read 32/32 bytes at offset 3221225456
+32 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 *** done
-- 
2.26.2