iotests/307: Test iothread conflict for exports

Passing fixed-iothread=true should make iothread conflicts fatal,
whereas fixed-iothread=false should not.

Combine the second case with an error condition that is checked after
the iothread is handled, to verify that qemu does not crash if there is
such an error after changing the iothread failed.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210624083825.29224-3-mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Tested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/307

@@ -41,9 +41,11 @@ with iotests.FilePath('image') as img, \
     iotests.log('=== Launch VM ===')
 
     vm.add_object('iothread,id=iothread0')
+    vm.add_object('iothread,id=iothread1')
     vm.add_blockdev(f'file,filename={img},node-name=file')
     vm.add_blockdev(f'{iotests.imgfmt},file=file,node-name=fmt')
     vm.add_blockdev('raw,file=file,node-name=ro,read-only=on')
+    vm.add_blockdev('null-co,node-name=null')
     vm.add_device(f'id=scsi0,driver=virtio-scsi,iothread=iothread0')
     vm.launch()
 
@@ -74,6 +76,19 @@ with iotests.FilePath('image') as img, \
     vm.qmp_log('query-block-exports')
     iotests.qemu_nbd_list_log('-k', socket)
 
+    iotests.log('\n=== Add export with conflicting iothread ===')
+
+    vm.qmp_log('device_add', id='sdb', driver='scsi-hd', drive='null')
+
+    # Should fail because of fixed-iothread
+    vm.qmp_log('block-export-add', id='export1', type='nbd', node_name='null',
+               iothread='iothread1', fixed_iothread=True, writable=True)
+
+    # Should ignore the iothread conflict, but then fail because of the
+    # permission conflict (and not crash)
+    vm.qmp_log('block-export-add', id='export1', type='nbd', node_name='null',
+               iothread='iothread1', fixed_iothread=False, writable=True)
+
     iotests.log('\n=== Add a writable export ===')
 
     # This fails because share-rw=off

tests/qemu-iotests/307.out

@@ -51,6 +51,14 @@ exports available: 1
    base:allocation
 
 
+=== Add export with conflicting iothread ===
+{"execute": "device_add", "arguments": {"drive": "null", "driver": "scsi-hd", "id": "sdb"}}
+{"return": {}}
+{"execute": "block-export-add", "arguments": {"fixed-iothread": true, "id": "export1", "iothread": "iothread1", "node-name": "null", "type": "nbd", "writable": true}}
+{"error": {"class": "GenericError", "desc": "Cannot change iothread of active block backend"}}
+{"execute": "block-export-add", "arguments": {"fixed-iothread": false, "id": "export1", "iothread": "iothread1", "node-name": "null", "type": "nbd", "writable": true}}
+{"error": {"class": "GenericError", "desc": "Permission conflict on node 'null': permissions 'write' are both required by an unnamed block device (uses node 'null' as 'root' child) and unshared by block device 'sdb' (uses node 'null' as 'root' child)."}}
+
 === Add a writable export ===
 {"execute": "block-export-add", "arguments": {"description": "This is the writable second export", "id": "export1", "name": "export1", "node-name": "fmt", "type": "nbd", "writable": true, "writethrough": true}}
 {"error": {"class": "GenericError", "desc": "Permission conflict on node 'fmt': permissions 'write' are both required by an unnamed block device (uses node 'fmt' as 'root' child) and unshared by block device 'sda' (uses node 'fmt' as 'root' child)."}}