iotests: Test NBD client reconnection

The test for an NBD client. The NBD server is disconnected after the
client write request. The NBD client should reconnect and complete
the write operation.

Suggested-by: Denis V. Lunev <den@openvz.org>
Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Eric Blake <eblake@redhat.com>
Message-Id: <1573529976-815699-1-git-send-email-andrey.shinkevich@virtuozzo.com>

tests/qemu-iotests/277

@@ -0,0 +1,96 @@
+#!/usr/bin/env python
+#
+# Test NBD client reconnection
+#
+# Copyright (c) 2019 Virtuozzo International GmbH
+#
+# 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/>.
+#
+
+import os
+import subprocess
+import iotests
+from iotests import file_path, log
+
+
+nbd_sock, conf_file = file_path('nbd-sock', 'nbd-fault-injector.conf')
+
+
+def make_conf_file(event):
+    """
+    Create configuration file for the nbd-fault-injector.py
+
+    :param event: which event the server should close a connection on
+    """
+    with open(conf_file, 'w') as conff:
+        conff.write('[inject-error]\nevent={}\nwhen=after'.format(event))
+
+
+def start_server_NBD(event):
+    make_conf_file(event)
+
+    srv = subprocess.Popen(['nbd-fault-injector.py', '--classic-negotiation',
+                           nbd_sock, conf_file], stdout=subprocess.PIPE,
+                           stderr=subprocess.STDOUT, universal_newlines=True)
+    line = srv.stdout.readline()
+    if 'Listening on ' in line:
+        log('NBD server: started')
+    else:
+        log('NBD server: ' + line.rstrip())
+
+    return srv
+
+
+def start_client_NBD():
+    log('NBD client: QEMU-IO write')
+    args = iotests.qemu_io_args_no_fmt + \
+        ['-c', 'write -P 0x7 0 3M', '--image-opts',
+         'driver=nbd,server.type=unix,server.path={},'
+         'reconnect-delay=7'.format(nbd_sock)]
+    clt = subprocess.Popen(args, stdout=subprocess.PIPE,
+                           stderr=subprocess.STDOUT,
+                           universal_newlines=True)
+    return clt
+
+
+def check_proc_NBD(proc, connector):
+    try:
+        outs, errs = proc.communicate(timeout=10)
+
+        if proc.returncode < 0:
+            log('NBD {}: EXIT SIGNAL {}\n'.format(connector, proc.returncode))
+            log(outs)
+        else:
+            msg = outs.split('\n', 1)
+            log('NBD {}: {}'.format(connector, msg[0]))
+
+    except subprocess.TimeoutExpired:
+        proc.kill()
+        log('NBD {}: ERROR timeout expired'.format(connector))
+    finally:
+        if connector == 'server':
+            os.remove(nbd_sock)
+            os.remove(conf_file)
+
+
+srv = start_server_NBD('data')
+clt = start_client_NBD()
+# The server should close the connection after a client write request
+check_proc_NBD(srv, 'server')
+# Start the NBD server again
+srv = start_server_NBD('reply')
+# The client should reconnect and complete the write operation
+check_proc_NBD(clt, 'client')
+# Make it sure that server terminated
+check_proc_NBD(srv, 'server')

tests/qemu-iotests/277.out

@@ -0,0 +1,6 @@
+NBD server: started
+NBD client: QEMU-IO write
+NBD server: Closing connection on rule match inject-error
+NBD server: started
+NBD client: wrote 3145728/3145728 bytes at offset 0
+NBD server: Closing connection on rule match inject-error

tests/qemu-iotests/group

@@ -285,3 +285,4 @@
 270 rw backing quick
 272 rw
 273 backing quick
+277 rw quick

tests/qemu-iotests/iotests.py

@@ -47,6 +47,11 @@ qemu_io_args = [os.environ.get('QEMU_IO_PROG', 'qemu-io')]
 if os.environ.get('QEMU_IO_OPTIONS'):
     qemu_io_args += os.environ['QEMU_IO_OPTIONS'].strip().split(' ')
 
+qemu_io_args_no_fmt = [os.environ.get('QEMU_IO_PROG', 'qemu-io')]
+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')]
 if os.environ.get('QEMU_NBD_OPTIONS'):
     qemu_nbd_args += os.environ['QEMU_NBD_OPTIONS'].strip().split(' ')

tests/qemu-iotests/nbd-fault-injector.py

@@ -115,7 +115,8 @@ class FaultInjectionSocket(object):
             if rule.match(event, io):
                 if rule.when == 0 or bufsize is None:
                     print('Closing connection on rule match %s' % rule.name)
-                    self.sock.flush()
+                    self.sock.close()
+                    sys.stdout.flush()
                     sys.exit(0)
                 if rule.when != -1:
                     return rule.when