diff mbox series

[v3] iotests: Test NBD client reconnection

Message ID 1572627272-23359-1-git-send-email-andrey.shinkevich@virtuozzo.com (mailing list archive)
State New, archived
Headers show
Series [v3] iotests: Test NBD client reconnection | expand

Commit Message

Andrey Shinkevich Nov. 1, 2019, 4:54 p.m. UTC 
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>
---
 tests/qemu-iotests/277                   | 102 +++++++++++++++++++++++++++++++
 tests/qemu-iotests/277.out               |   6 ++
 tests/qemu-iotests/group                 |   1 +
 tests/qemu-iotests/iotests.py            |   5 ++
 tests/qemu-iotests/nbd-fault-injector.py |   3 +-
 5 files changed, 116 insertions(+), 1 deletion(-)
 create mode 100755 tests/qemu-iotests/277
 create mode 100644 tests/qemu-iotests/277.out

Comments

Vladimir Sementsov-Ogievskiy Nov. 8, 2019, 1:49 p.m. UTC | #1 
01.11.2019 19:54, Andrey Shinkevich wrote:
> 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>
> ---
>   tests/qemu-iotests/277                   | 102 +++++++++++++++++++++++++++++++
>   tests/qemu-iotests/277.out               |   6 ++
>   tests/qemu-iotests/group                 |   1 +
>   tests/qemu-iotests/iotests.py            |   5 ++
>   tests/qemu-iotests/nbd-fault-injector.py |   3 +-
>   5 files changed, 116 insertions(+), 1 deletion(-)
>   create mode 100755 tests/qemu-iotests/277
>   create mode 100644 tests/qemu-iotests/277.out
> 
> diff --git a/tests/qemu-iotests/277 b/tests/qemu-iotests/277
> new file mode 100755
> index 0000000..e4e6730
> --- /dev/null
> +++ b/tests/qemu-iotests/277
> @@ -0,0 +1,102 @@
> +#!/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
> +
> +
> +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
> +    """
> +    if os.path.exists(conf_file):
> +        os.remove(conf_file)

a bit strange for my eyes to see global variable not defined higher in the file than used..

> +
> +    with open(conf_file, "w+") as conff:
> +        conff.write("[inject-error]\nevent={}\nwhen=after".format(event))

better open with "w" and don't need to remove file before it.

> +
> +
> +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

Could you reuse QemuIoInteractive as a client?

> +
> +
> +def check_proc_NBD(proc, connector):
> +    try:
> +        exitcode = proc.wait(timeout=10)
> +
> +        if exitcode < 0:
> +            log('NBD {}: EXIT SIGNAL {}\n'.format(connector, -exitcode))
> +            log(proc.communicate()[0])
> +        else:
> +            line = proc.stdout.readline()


could we use proc.communicate() for both cases, what is the difference?

> +            log('NBD {}: {}'.format(connector, line.rstrip()))
> +
> +    except subprocess.TimeoutExpired:
> +        proc.kill()
> +        log('NBD {}: ERROR timeout expired'.format(connector))
> +    finally:
> +        if connector == 'server':
> +            os.remove(nbd_sock)
> +            os.remove(conf_file)
> +
> +
> +conf_file = os.path.join(iotests.test_dir, "nbd-fault-injector.conf")

use file_path here too.

> +nbd_sock = file_path('nbd-sock')
> +nbd_uri = 'nbd+unix:///?socket=' + nbd_sock

unused variable

> +if os.path.exists(nbd_sock):
> +    os.remove(nbd_sock)

I don't think we need this

> +
> +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')
> diff --git a/tests/qemu-iotests/277.out b/tests/qemu-iotests/277.out
> new file mode 100644
> index 0000000..45404b3
> --- /dev/null
> +++ b/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
> diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
> index af322af..22ef1b8 100644
> --- a/tests/qemu-iotests/group
> +++ b/tests/qemu-iotests/group
> @@ -282,3 +282,4 @@
>   267 rw auto quick snapshot
>   268 rw auto quick
>   270 rw backing quick
> +277 rw
> diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
> index 709def4..0d16303 100644
> --- a/tests/qemu-iotests/iotests.py
> +++ b/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(' ')
> diff --git a/tests/qemu-iotests/nbd-fault-injector.py b/tests/qemu-iotests/nbd-fault-injector.py
> index 6b2d659..7e2dab6 100755
> --- a/tests/qemu-iotests/nbd-fault-injector.py
> +++ b/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()

Why do you need this? It should be mentioned in commit message I think.

>                       sys.exit(0)
>                   if rule.when != -1:
>                       return rule.when
>
Roman Kagan Nov. 8, 2019, 2:05 p.m. UTC | #2 
On Fri, Nov 08, 2019 at 01:49:50PM +0000, Vladimir Sementsov-Ogievskiy wrote:
> 01.11.2019 19:54, Andrey Shinkevich wrote:
> > +def check_proc_NBD(proc, connector):
> > +    try:
> > +        exitcode = proc.wait(timeout=10)
> > +
> > +        if exitcode < 0:
> > +            log('NBD {}: EXIT SIGNAL {}\n'.format(connector, -exitcode))
> > +            log(proc.communicate()[0])
> > +        else:
> > +            line = proc.stdout.readline()
> 
> 
> could we use proc.communicate() for both cases, what is the difference?

In fact if proc produces any non-trivial amount of output you are better
off using .communicate() otherwise your child may block on output and
never exit.  See
https://docs.python.org/3/library/subprocess.html#subprocess.Popen.communicate
for how to express the above logic correctly.  The exit code *after*
.communicate is available in .returncode.

> 
> > +            log('NBD {}: {}'.format(connector, line.rstrip()))
> > +
> > +    except subprocess.TimeoutExpired:
> > +        proc.kill()
> > +        log('NBD {}: ERROR timeout expired'.format(connector))
> > +    finally:
> > +        if connector == 'server':
> > +            os.remove(nbd_sock)
> > +            os.remove(conf_file)

Roman.
Andrey Shinkevich Nov. 11, 2019, 9:07 a.m. UTC | #3 
On 08/11/2019 16:49, Vladimir Sementsov-Ogievskiy wrote:
> 01.11.2019 19:54, Andrey Shinkevich wrote:
>> 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>
>> ---
>>    tests/qemu-iotests/277                   | 102 +++++++++++++++++++++++++++++++
>>    tests/qemu-iotests/277.out               |   6 ++
>>    tests/qemu-iotests/group                 |   1 +
>>    tests/qemu-iotests/iotests.py            |   5 ++
>>    tests/qemu-iotests/nbd-fault-injector.py |   3 +-
>>    5 files changed, 116 insertions(+), 1 deletion(-)
>>    create mode 100755 tests/qemu-iotests/277
>>    create mode 100644 tests/qemu-iotests/277.out
>>
>> diff --git a/tests/qemu-iotests/277 b/tests/qemu-iotests/277
>> new file mode 100755
>> index 0000000..e4e6730
>> --- /dev/null
>> +++ b/tests/qemu-iotests/277
>> @@ -0,0 +1,102 @@
>> +#!/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
>> +
>> +
>> +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
>> +    """
>> +    if os.path.exists(conf_file):
>> +        os.remove(conf_file)
> 
> a bit strange for my eyes to see global variable not defined higher in the file than used..
> 
>> +
>> +    with open(conf_file, "w+") as conff:
>> +        conff.write("[inject-error]\nevent={}\nwhen=after".format(event))
> 
> better open with "w" and don't need to remove file before it.
> 
>> +
>> +
>> +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
> 
> Could you reuse QemuIoInteractive as a client?
> 

Thanks for your review.
The class QemuIoInteractive uses the qemu_io_args variable that includes 
the format option which conflicts with the option 'image-opts'.

>> +
>> +
>> +def check_proc_NBD(proc, connector):
>> +    try:
>> +        exitcode = proc.wait(timeout=10)
>> +
>> +        if exitcode < 0:
>> +            log('NBD {}: EXIT SIGNAL {}\n'.format(connector, -exitcode))
>> +            log(proc.communicate()[0])
>> +        else:
>> +            line = proc.stdout.readline()
> 
> 
> could we use proc.communicate() for both cases, what is the difference?
> 
>> +            log('NBD {}: {}'.format(connector, line.rstrip()))
>> +
>> +    except subprocess.TimeoutExpired:
>> +        proc.kill()
>> +        log('NBD {}: ERROR timeout expired'.format(connector))
>> +    finally:
>> +        if connector == 'server':
>> +            os.remove(nbd_sock)
>> +            os.remove(conf_file)
>> +
>> +
>> +conf_file = os.path.join(iotests.test_dir, "nbd-fault-injector.conf")
> 
> use file_path here too.
> 
>> +nbd_sock = file_path('nbd-sock')
>> +nbd_uri = 'nbd+unix:///?socket=' + nbd_sock
> 
> unused variable
> 
>> +if os.path.exists(nbd_sock):
>> +    os.remove(nbd_sock)
> 
> I don't think we need this
> 
>> +
>> +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')
>> diff --git a/tests/qemu-iotests/277.out b/tests/qemu-iotests/277.out
>> new file mode 100644
>> index 0000000..45404b3
>> --- /dev/null
>> +++ b/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
>> diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
>> index af322af..22ef1b8 100644
>> --- a/tests/qemu-iotests/group
>> +++ b/tests/qemu-iotests/group
>> @@ -282,3 +282,4 @@
>>    267 rw auto quick snapshot
>>    268 rw auto quick
>>    270 rw backing quick
>> +277 rw
>> diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
>> index 709def4..0d16303 100644
>> --- a/tests/qemu-iotests/iotests.py
>> +++ b/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(' ')
>> diff --git a/tests/qemu-iotests/nbd-fault-injector.py b/tests/qemu-iotests/nbd-fault-injector.py
>> index 6b2d659..7e2dab6 100755
>> --- a/tests/qemu-iotests/nbd-fault-injector.py
>> +++ b/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()
> 
> Why do you need this? It should be mentioned in commit message I think.
> 

The socket object does not have the flush() method. I guess the author 
wanted to flush from the stdout.

>>                        sys.exit(0)
>>                    if rule.when != -1:
>>                        return rule.when
>>
> 
>
Andrey Shinkevich Nov. 11, 2019, 9:18 a.m. UTC | #4 
On 08/11/2019 17:05, Roman Kagan wrote:
> On Fri, Nov 08, 2019 at 01:49:50PM +0000, Vladimir Sementsov-Ogievskiy wrote:
>> 01.11.2019 19:54, Andrey Shinkevich wrote:
>>> +def check_proc_NBD(proc, connector):
>>> +    try:
>>> +        exitcode = proc.wait(timeout=10)
>>> +
>>> +        if exitcode < 0:
>>> +            log('NBD {}: EXIT SIGNAL {}\n'.format(connector, -exitcode))
>>> +            log(proc.communicate()[0])
>>> +        else:
>>> +            line = proc.stdout.readline()
>>
>>
>> could we use proc.communicate() for both cases, what is the difference?
> 
> In fact if proc produces any non-trivial amount of output you are better
> off using .communicate() otherwise your child may block on output and
> never exit.  See
> https://docs.python.org/3/library/subprocess.html#subprocess.Popen.communicate
> for how to express the above logic correctly.  The exit code *after*
> .communicate is available in .returncode.
> 

The pattern by the link above does not work (Python3):

proc = subprocess.Popen(...)
try:
     outs, errs = proc.communicate(timeout=15)
except TimeoutExpired:
     proc.kill()
     outs, errs = proc.communicate()

as 'proc' cannot be used for output after being killed. It results in 
another exception being raised.

Andrey

>>
>>> +            log('NBD {}: {}'.format(connector, line.rstrip()))
>>> +
>>> +    except subprocess.TimeoutExpired:
>>> +        proc.kill()
>>> +        log('NBD {}: ERROR timeout expired'.format(connector))
>>> +    finally:
>>> +        if connector == 'server':
>>> +            os.remove(nbd_sock)
>>> +            os.remove(conf_file)
> 
> Roman.
>
Roman Kagan Nov. 11, 2019, 9:48 a.m. UTC | #5 
On Mon, Nov 11, 2019 at 12:18:48PM +0300, Andrey Shinkevich wrote:
> 
> 
> On 08/11/2019 17:05, Roman Kagan wrote:
> > On Fri, Nov 08, 2019 at 01:49:50PM +0000, Vladimir Sementsov-Ogievskiy wrote:
> >> 01.11.2019 19:54, Andrey Shinkevich wrote:
> >>> +def check_proc_NBD(proc, connector):
> >>> +    try:
> >>> +        exitcode = proc.wait(timeout=10)
> >>> +
> >>> +        if exitcode < 0:
> >>> +            log('NBD {}: EXIT SIGNAL {}\n'.format(connector, -exitcode))
> >>> +            log(proc.communicate()[0])
> >>> +        else:
> >>> +            line = proc.stdout.readline()
> >>
> >>
> >> could we use proc.communicate() for both cases, what is the difference?
> > 
> > In fact if proc produces any non-trivial amount of output you are better
> > off using .communicate() otherwise your child may block on output and
> > never exit.  See
> > https://docs.python.org/3/library/subprocess.html#subprocess.Popen.communicate
> > for how to express the above logic correctly.  The exit code *after*
> > .communicate is available in .returncode.
> > 
> 
> The pattern by the link above does not work (Python3):
> 
> proc = subprocess.Popen(...)
> try:
>      outs, errs = proc.communicate(timeout=15)
> except TimeoutExpired:
>      proc.kill()
>      outs, errs = proc.communicate()
> 
> as 'proc' cannot be used for output after being killed. It results in 
> another exception being raised.

Of course it can't.  You need to use the strings returned by
.communicate().

Roman.
diff mbox series

Patch

diff --git a/tests/qemu-iotests/277 b/tests/qemu-iotests/277
new file mode 100755
index 0000000..e4e6730
--- /dev/null
+++ b/tests/qemu-iotests/277
@@ -0,0 +1,102 @@ 
+#!/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
+
+
+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
+    """
+    if os.path.exists(conf_file):
+        os.remove(conf_file)
+
+    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:
+        exitcode = proc.wait(timeout=10)
+
+        if exitcode < 0:
+            log('NBD {}: EXIT SIGNAL {}\n'.format(connector, -exitcode))
+            log(proc.communicate()[0])
+        else:
+            line = proc.stdout.readline()
+            log('NBD {}: {}'.format(connector, line.rstrip()))
+
+    except subprocess.TimeoutExpired:
+        proc.kill()
+        log('NBD {}: ERROR timeout expired'.format(connector))
+    finally:
+        if connector == 'server':
+            os.remove(nbd_sock)
+            os.remove(conf_file)
+
+
+conf_file = os.path.join(iotests.test_dir, "nbd-fault-injector.conf")
+nbd_sock = file_path('nbd-sock')
+nbd_uri = 'nbd+unix:///?socket=' + nbd_sock
+if os.path.exists(nbd_sock):
+    os.remove(nbd_sock)
+
+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')
diff --git a/tests/qemu-iotests/277.out b/tests/qemu-iotests/277.out
new file mode 100644
index 0000000..45404b3
--- /dev/null
+++ b/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
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index af322af..22ef1b8 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -282,3 +282,4 @@ 
 267 rw auto quick snapshot
 268 rw auto quick
 270 rw backing quick
+277 rw
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index 709def4..0d16303 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/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(' ')
diff --git a/tests/qemu-iotests/nbd-fault-injector.py b/tests/qemu-iotests/nbd-fault-injector.py
index 6b2d659..7e2dab6 100755
--- a/tests/qemu-iotests/nbd-fault-injector.py
+++ b/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