[29/29] iotests: Test block-export-* QMP interface

diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index 6fed77487e..a842a9f92d 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -67,7 +67,8 @@  if os.environ.get('QEMU_IO_OPTIONS_NO_FMT'):
     qemu_io_args_no_fmt += \
         os.environ['QEMU_IO_OPTIONS_NO_FMT'].strip().split(' ')
 
-qemu_nbd_args = [os.environ.get('QEMU_NBD_PROG', 'qemu-nbd')]
+qemu_nbd_prog = [os.environ.get('QEMU_NBD_PROG', 'qemu-nbd')]
+qemu_nbd_args = qemu_nbd_prog
 if os.environ.get('QEMU_NBD_OPTIONS'):
     qemu_nbd_args += os.environ['QEMU_NBD_OPTIONS'].strip().split(' ')
 
@@ -283,6 +284,14 @@  def qemu_nbd_early_pipe(*args: str) -> Tuple[int, str]:
                                                    *full_args)
     return returncode, output if returncode else ''
 
+def qemu_nbd_list(*args: str) -> str:
+    '''Run qemu-nbd to list remote exports'''
+    full_args = qemu_nbd_prog + ['-L'] + list(args)
+    output, _ = qemu_tool_pipe_and_status('qemu-nbd', *full_args)
+    log(output, filters=[filter_testfiles])
+    return output
+
+
 @contextmanager
 def qemu_nbd_popen(*args):
     '''Context manager running qemu-nbd within the context'''
diff --git a/tests/qemu-iotests/307 b/tests/qemu-iotests/307
new file mode 100755
index 0000000000..06b9eeb15f
--- /dev/null
+++ b/tests/qemu-iotests/307
@@ -0,0 +1,117 @@ 
+#!/usr/bin/env python3
+#
+# Copyright (C) 2020 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# Creator/Owner: Kevin Wolf <kwolf@redhat.com>
+#
+# Test the block export QAPI interfaces
+
+import iotests
+import os
+
+# Formats that have a request alignment != 1 result in different output for
+# qemu-nbd -L ("min block")
+iotests.script_initialize(
+    supported_fmts=['raw', 'qcow2', 'vmdk'],
+    supported_platforms=['linux'],
+)
+
+with iotests.FilePath('image') as img, \
+     iotests.FilePath('socket') as socket, \
+     iotests.VM() as vm:
+
+    iotests.qemu_img('create', '-f', iotests.imgfmt, img, '64M')
+    iotests.qemu_io_log('-f', iotests.imgfmt, '-c', 'write -P 0x11 0 4k', img)
+
+    iotests.log('=== Launch VM ===')
+
+    virtio_scsi_device = iotests.get_virtio_scsi_device()
+
+    vm.add_object('iothread,id=iothread0')
+    vm.add_blockdev('file,filename=%s,node-name=file' % (img))
+    vm.add_blockdev('%s,file=file,node-name=fmt' % (iotests.imgfmt))
+    vm.add_blockdev('raw,file=file,node-name=ro,read-only=on')
+    vm.add_device('id=scsi0,driver=%s,iothread=iothread0' % virtio_scsi_device)
+    vm.launch()
+
+    vm.qmp_log('nbd-server-start',
+               addr={'type': 'unix', 'data': {'path': socket}},
+               filters=(iotests.filter_qmp_testfiles, ))
+    vm.qmp_log('query-block-exports')
+
+    iotests.log('\n=== Create a read-only NBD export ===')
+
+    vm.qmp_log('block-export-add', id='export0', type='nbd', node_name='fmt')
+    vm.qmp_log('query-block-exports')
+
+    iotests.qemu_nbd_list('-k', socket)
+
+    iotests.log('\n=== Try a few invalid things ===')
+
+    vm.qmp_log('block-export-add', id='#invalid_id', type='nbd', node_name='fmt')
+    vm.qmp_log('block-export-add', id='export0', type='nbd', node_name='fmt')
+    vm.qmp_log('block-export-add', id='export1', type='nbd', node_name='ro',
+               writable=True)
+    vm.qmp_log('block-export-del', id='export1')
+    vm.qmp_log('query-block-exports')
+
+    iotests.log('\n=== Move export to an iothread ===')
+
+    vm.qmp_log('device_add', id='sda', driver='scsi-hd', drive='fmt')
+    vm.qmp_log('query-block-exports')
+    iotests.qemu_nbd_list('-k', socket)
+
+    iotests.log('\n=== Add a writable export ===')
+
+    # This fails because share-rw=off
+    vm.qmp_log('block-export-add', id='export1', type='nbd', node_name='fmt',
+               name='export1', writable=True, writethrough=True,
+               description='This is the writable second export')
+
+    vm.qmp_log('device_del', id='sda')
+    event = vm.event_wait(name="DEVICE_DELETED",
+                          match={'data': {'device': 'sda'}})
+    iotests.log(event, filters=[iotests.filter_qmp_event])
+    vm.qmp_log('device_add', id='sda', driver='scsi-hd', drive='fmt',
+               share_rw=True)
+
+    # Now it should work
+    vm.qmp_log('block-export-add', id='export1', type='nbd', node_name='fmt',
+               name='export1', writable=True, writethrough=True,
+               description='This is the writable second export')
+
+    vm.qmp_log('query-block-exports')
+    iotests.qemu_nbd_list('-k', socket)
+
+    iotests.log('\n=== Connect qemu-io to export1, try removing exports ===')
+
+    nbd_url = 'nbd+unix:///export1?socket=%s' % socket
+    qemu_io = iotests.QemuIoInteractive('-f', 'raw', nbd_url)
+
+    iotests.log(qemu_io.cmd('read -P 0x11 0 4k'),
+                filters=[iotests.filter_qemu_io])
+    iotests.log(qemu_io.cmd('write -P 0x22 4k 4k'),
+                filters=[iotests.filter_qemu_io])
+
+    vm.qmp_log('block-export-del', id='export1')
+    vm.qmp_log('block-export-del', id='export0')
+    qemu_io.close()
+
+    vm.qmp_log('query-block-exports')
+    iotests.qemu_nbd_list('-k', socket)
+
+    iotests.log('\n=== Shut down QEMU ===')
+    vm.shutdown()
diff --git a/tests/qemu-iotests/307.out b/tests/qemu-iotests/307.out
new file mode 100644
index 0000000000..d8e572cac0
--- /dev/null
+++ b/tests/qemu-iotests/307.out
@@ -0,0 +1,111 @@ 
+wrote 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+=== Launch VM ===
+{"execute": "nbd-server-start", "arguments": {"addr": {"data": {"path": "TEST_DIR/PID-socket"}, "type": "unix"}}}
+{"return": {}}
+{"execute": "query-block-exports", "arguments": {}}
+{"return": []}
+
+=== Create a read-only NBD export ===
+{"execute": "block-export-add", "arguments": {"id": "export0", "node-name": "fmt", "type": "nbd"}}
+{"return": {}}
+{"execute": "query-block-exports", "arguments": {}}
+{"return": [{"id": "export0", "node-name": "fmt", "shutting-down": false, "type": "nbd"}]}
+exports available: 1
+ export: 'fmt'
+  size:  67108864
+  flags: 0x58f ( readonly flush fua df multi cache )
+  min block: 1
+  opt block: 4096
+  max block: 33554432
+  available meta contexts: 1
+   base:allocation
+
+
+=== Try a few invalid things ===
+{"execute": "block-export-add", "arguments": {"id": "#invalid_id", "node-name": "fmt", "type": "nbd"}}
+{"error": {"class": "GenericError", "desc": "Invalid block export id"}}
+{"execute": "block-export-add", "arguments": {"id": "export0", "node-name": "fmt", "type": "nbd"}}
+{"error": {"class": "GenericError", "desc": "Block export id 'export0' is already in use"}}
+{"execute": "block-export-add", "arguments": {"id": "export1", "node-name": "ro", "type": "nbd", "writable": true}}
+{"error": {"class": "GenericError", "desc": "Cannot export read-only node as writable"}}
+{"execute": "block-export-del", "arguments": {"id": "export1"}}
+{"error": {"class": "GenericError", "desc": "Export 'export1' is not found"}}
+{"execute": "query-block-exports", "arguments": {}}
+{"return": [{"id": "export0", "node-name": "fmt", "shutting-down": false, "type": "nbd"}]}
+
+=== Move export to an iothread ===
+{"execute": "device_add", "arguments": {"drive": "fmt", "driver": "scsi-hd", "id": "sda"}}
+{"return": {}}
+{"execute": "query-block-exports", "arguments": {}}
+{"return": [{"id": "export0", "node-name": "fmt", "shutting-down": false, "type": "nbd"}]}
+exports available: 1
+ export: 'fmt'
+  size:  67108864
+  flags: 0x58f ( readonly flush fua df multi cache )
+  min block: 1
+  opt block: 4096
+  max block: 33554432
+  available meta contexts: 1
+   base:allocation
+
+
+=== 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": "Conflicts with use by sda as 'root', which does not allow 'write' on fmt"}}
+{"execute": "device_del", "arguments": {"id": "sda"}}
+{"return": {}}
+{"data": {"device": "sda", "path": "/machine/peripheral/sda"}, "event": "DEVICE_DELETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+{"execute": "device_add", "arguments": {"drive": "fmt", "driver": "scsi-hd", "id": "sda", "share-rw": true}}
+{"return": {}}
+{"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}}
+{"return": {}}
+{"execute": "query-block-exports", "arguments": {}}
+{"return": [{"id": "export1", "node-name": "fmt", "shutting-down": false, "type": "nbd"}, {"id": "export0", "node-name": "fmt", "shutting-down": false, "type": "nbd"}]}
+exports available: 2
+ export: 'fmt'
+  size:  67108864
+  flags: 0x58f ( readonly flush fua df multi cache )
+  min block: 1
+  opt block: 4096
+  max block: 33554432
+  available meta contexts: 1
+   base:allocation
+ export: 'export1'
+  description: This is the writable second export
+  size:  67108864
+  flags: 0xced ( flush fua trim zeroes df cache fast-zero )
+  min block: 1
+  opt block: 4096
+  max block: 33554432
+  available meta contexts: 1
+   base:allocation
+
+
+=== Connect qemu-io to export1, try removing exports ===
+read 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+wrote 4096/4096 bytes at offset 4096
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+{"execute": "block-export-del", "arguments": {"id": "export1"}}
+{"error": {"class": "GenericError", "desc": "export 'export1' still in use"}}
+{"execute": "block-export-del", "arguments": {"id": "export0"}}
+{"return": {}}
+{"execute": "query-block-exports", "arguments": {}}
+{"return": [{"id": "export1", "node-name": "fmt", "shutting-down": false, "type": "nbd"}]}
+exports available: 1
+ export: 'export1'
+  description: This is the writable second export
+  size:  67108864
+  flags: 0xced ( flush fua trim zeroes df cache fast-zero )
+  min block: 1
+  opt block: 4096
+  max block: 33554432
+  available meta contexts: 1
+   base:allocation
+
+
+=== Shut down QEMU ===
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index 5cad015231..f0e9030aba 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -313,3 +313,4 @@ 
 302 quick
 303 rw quick
 304 rw quick
+307 rw quick export