[PATCH for-6.1?] iotest: Further enhance qemu-img-bitmaps

[Eric Blake <eblake@redhat.com>]

Add a regression test to make sure we detect attempts to use 'qemu-img
bitmap' to modify an in-use local file.

Suggested-by: Nir Soffer <nsoffer@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---

Sadly, this missed my bitmaps pull request today.  If there's any
reason to respin that pull request, I'm inclined to add this in, as it
just touches the iotests; otherwise, if it slips to 6.2 it's not too
bad.

 tests/qemu-iotests/tests/qemu-img-bitmaps     | 6 ++++++
 tests/qemu-iotests/tests/qemu-img-bitmaps.out | 5 +++++
 2 files changed, 11 insertions(+)

diff --git a/tests/qemu-iotests/tests/qemu-img-bitmaps b/tests/qemu-iotests/tests/qemu-img-bitmaps
index 7a3fe8c3d37a..3b6fade11735 100755
--- a/tests/qemu-iotests/tests/qemu-img-bitmaps
+++ b/tests/qemu-iotests/tests/qemu-img-bitmaps
@@ -129,6 +129,12 @@ $QEMU_IMG map --output=json --image-opts \
 $QEMU_IMG map --output=json --image-opts \
     "$IMG,x-dirty-bitmap=qemu:dirty-bitmap:b3" | _filter_qemu_img_map

+echo
+echo "=== bitmap command fails to modify image already in use ==="
+echo
+
+$QEMU_IMG bitmap --add "$TEST_IMG" b4 2>&1 | _filter_testdir
+
 nbd_server_stop

 echo
diff --git a/tests/qemu-iotests/tests/qemu-img-bitmaps.out b/tests/qemu-iotests/tests/qemu-img-bitmaps.out
index e851f0320ecb..c6e12dd700aa 100644
--- a/tests/qemu-iotests/tests/qemu-img-bitmaps.out
+++ b/tests/qemu-iotests/tests/qemu-img-bitmaps.out
@@ -116,6 +116,11 @@ Format specific information:
 { "start": 2097152, "length": 1048576, "depth": 0, "present": false, "zero": false, "data": false},
 { "start": 3145728, "length": 7340032, "depth": 0, "present": true, "zero": false, "data": true, "offset": OFFSET}]

+=== bitmap command fails to modify image already in use ===
+
+qemu-img: Could not open 'TEST_DIR/t.qcow2': Failed to get "write" lock
+Is another process using the image [TEST_DIR/t.qcow2]?
+
 === Check handling of inconsistent bitmap ===

 image: TEST_DIR/t.IMGFMT
-- 
2.31.1