[PULL 27/28] iotests: Test reopening multiple devices at the same time

[Kevin Wolf <kwolf@redhat.com>]

From: Alberto Garcia <berto@igalia.com>

This test swaps the images used by two active block devices.

This is now possible thanks to the new ability to run
x-blockdev-reopen on multiple devices at the same time.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210708114709.206487-6-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 tests/qemu-iotests/245     | 47 ++++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/245.out |  4 ++--
 2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/tests/qemu-iotests/245 b/tests/qemu-iotests/245
index ca08955207..8bc8101e6d 100755
--- a/tests/qemu-iotests/245
+++ b/tests/qemu-iotests/245
@@ -649,6 +649,53 @@ class TestBlockdevReopen(iotests.QMPTestCase):
                                          '-c', 'read -P 0x40 0x40008 1',
                                          '-c', 'read -P 0x80 0x40010 1', hd_path[0])
 
+    # Swap the disk images of two active block devices
+    def test_swap_files(self):
+        # Add hd0 and hd2 (none of them with backing files)
+        opts0 = hd_opts(0)
+        result = self.vm.qmp('blockdev-add', conv_keys = False, **opts0)
+        self.assert_qmp(result, 'return', {})
+
+        opts2 = hd_opts(2)
+        result = self.vm.qmp('blockdev-add', conv_keys = False, **opts2)
+        self.assert_qmp(result, 'return', {})
+
+        # Write different data to both block devices
+        self.run_qemu_io("hd0", "write -P 0xa0 0 1k")
+        self.run_qemu_io("hd2", "write -P 0xa2 0 1k")
+
+        # Check that the data reads correctly
+        self.run_qemu_io("hd0", "read  -P 0xa0 0 1k")
+        self.run_qemu_io("hd2", "read  -P 0xa2 0 1k")
+
+        # It's not possible to make a block device use an image that
+        # is already being used by the other device.
+        self.reopen(opts0, {'file': 'hd2-file'},
+                    "Permission conflict on node 'hd2-file': permissions "
+                    "'write, resize' are both required by node 'hd2' (uses "
+                    "node 'hd2-file' as 'file' child) and unshared by node "
+                    "'hd0' (uses node 'hd2-file' as 'file' child).")
+        self.reopen(opts2, {'file': 'hd0-file'},
+                    "Permission conflict on node 'hd0-file': permissions "
+                    "'write, resize' are both required by node 'hd0' (uses "
+                    "node 'hd0-file' as 'file' child) and unshared by node "
+                    "'hd2' (uses node 'hd0-file' as 'file' child).")
+
+        # But we can swap the images if we reopen both devices at the
+        # same time
+        opts0['file'] = 'hd2-file'
+        opts2['file'] = 'hd0-file'
+        self.reopenMultiple([opts0, opts2])
+        self.run_qemu_io("hd0", "read  -P 0xa2 0 1k")
+        self.run_qemu_io("hd2", "read  -P 0xa0 0 1k")
+
+        # And we can of course come back to the original state
+        opts0['file'] = 'hd0-file'
+        opts2['file'] = 'hd2-file'
+        self.reopenMultiple([opts0, opts2])
+        self.run_qemu_io("hd0", "read  -P 0xa0 0 1k")
+        self.run_qemu_io("hd2", "read  -P 0xa2 0 1k")
+
     # Misc reopen tests with different block drivers
     @iotests.skip_if_unsupported(['quorum', 'throttle'])
     def test_misc_drivers(self):
diff --git a/tests/qemu-iotests/245.out b/tests/qemu-iotests/245.out
index daf1e51922..4eced19294 100644
--- a/tests/qemu-iotests/245.out
+++ b/tests/qemu-iotests/245.out
@@ -17,8 +17,8 @@ read 1/1 bytes at offset 262152
 read 1/1 bytes at offset 262160
 1 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
-..............
+...............
 ----------------------------------------------------------------------
-Ran 24 tests
+Ran 25 tests
 
 OK
-- 
2.31.1