[PATCH] nbd:clear NBD_BOUND flag when NBD connection is closed

[PATCH] nbd:clear NBD_BOUND flag when NBD connection is closed

[medadyoung]

From: Medad <medadyoung@gmail.com>

    If we do NOT clear NBD_BOUND flag when NBD connection is closed,
    then the original NBD device could not be used again.

Signed-off-by: Medad <medadyoung@gmail.com>
---
 drivers/block/nbd.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 64278f4..5c88490 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -277,10 +277,14 @@ static void sock_shutdown(struct nbd_device *nbd)
 	struct nbd_config *config = nbd->config;
 	int i;
 
-	if (config->num_connections == 0)
+	if (config->num_connections == 0) {
+		clear_bit(NBD_BOUND, &config->runtime_flags);
 		return;
-	if (test_and_set_bit(NBD_DISCONNECTED, &config->runtime_flags))
+	}
+	if (test_and_set_bit(NBD_DISCONNECTED, &config->runtime_flags)) {
+		clear_bit(NBD_BOUND, &config->runtime_flags);
 		return;
+	}
 
 	for (i = 0; i < config->num_connections; i++) {
 		struct nbd_sock *nsock = config->socks[i];
@@ -944,7 +948,7 @@ static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
 		sockfd_put(old);
 
 		clear_bit(NBD_DISCONNECTED, &config->runtime_flags);
-
+		clear_bit(NBD_BOUND, &config->runtime_flags);
 		/* We take the tx_mutex in an error path in the recv_work, so we
 		 * need to queue_work outside of the tx_mutex.
 		 */
@@ -1020,6 +1024,7 @@ static int nbd_disconnect(struct nbd_device *nbd)
 	dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
 	set_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags);
 	send_disconnects(nbd);
+	clear_bit(NBD_BOUND, &config->runtime_flags);
 	return 0;
 }
 
-- 
2.7.4

Re: [PATCH] nbd:clear NBD_BOUND flag when NBD connection is closed

[Adriana Kobylak]

On 2018-12-11 00:17, medadyoung@gmail.com wrote:
> From: Medad <medadyoung@gmail.com>
> 
>     If we do NOT clear NBD_BOUND flag when NBD connection is closed,
>     then the original NBD device could not be used again.
> 
> Signed-off-by: Medad <medadyoung@gmail.com>

Tested on Witherspoon (OpenPOWER P9 with AST2500) and verified with
this patch that the NBD device could be disconnected/reconnected.

Tested by: Adriana Kobylak <anoo@linux.ibm.com>

> ---
>  drivers/block/nbd.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 64278f4..5c88490 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -277,10 +277,14 @@ static void sock_shutdown(struct nbd_device *nbd)
>  	struct nbd_config *config = nbd->config;
>  	int i;
> 
> -	if (config->num_connections == 0)
> +	if (config->num_connections == 0) {
> +		clear_bit(NBD_BOUND, &config->runtime_flags);
>  		return;
> -	if (test_and_set_bit(NBD_DISCONNECTED, &config->runtime_flags))
> +	}
> +	if (test_and_set_bit(NBD_DISCONNECTED, &config->runtime_flags)) {
> +		clear_bit(NBD_BOUND, &config->runtime_flags);
>  		return;
> +	}
> 
>  	for (i = 0; i < config->num_connections; i++) {
>  		struct nbd_sock *nsock = config->socks[i];
> @@ -944,7 +948,7 @@ static int nbd_reconnect_socket(struct nbd_device
> *nbd, unsigned long arg)
>  		sockfd_put(old);
> 
>  		clear_bit(NBD_DISCONNECTED, &config->runtime_flags);
> -
> +		clear_bit(NBD_BOUND, &config->runtime_flags);
>  		/* We take the tx_mutex in an error path in the recv_work, so we
>  		 * need to queue_work outside of the tx_mutex.
>  		 */
> @@ -1020,6 +1024,7 @@ static int nbd_disconnect(struct nbd_device *nbd)
>  	dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
>  	set_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags);
>  	send_disconnects(nbd);
> +	clear_bit(NBD_BOUND, &config->runtime_flags);
>  	return 0;
>  }

Re: [PATCH] nbd:clear NBD_BOUND flag when NBD connection is closed

[Adriana Kobylak]

Adding Josef (updated email address in the maintainers file).

On 2018-12-13 08:21, Adriana Kobylak wrote:
> On 2018-12-11 00:17, medadyoung@gmail.com wrote:
>> From: Medad <medadyoung@gmail.com>
>> 
>>     If we do NOT clear NBD_BOUND flag when NBD connection is closed,
>>     then the original NBD device could not be used again.
>> 
>> Signed-off-by: Medad <medadyoung@gmail.com>
> 
> Tested on Witherspoon (OpenPOWER P9 with AST2500) and verified with
> this patch that the NBD device could be disconnected/reconnected.
> 
> Tested by: Adriana Kobylak <anoo@linux.ibm.com>
> 
>> ---
>>  drivers/block/nbd.c | 11 ++++++++---
>>  1 file changed, 8 insertions(+), 3 deletions(-)
>> 
>> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
>> index 64278f4..5c88490 100644
>> --- a/drivers/block/nbd.c
>> +++ b/drivers/block/nbd.c
>> @@ -277,10 +277,14 @@ static void sock_shutdown(struct nbd_device 
>> *nbd)
>>  	struct nbd_config *config = nbd->config;
>>  	int i;
>> 
>> -	if (config->num_connections == 0)
>> +	if (config->num_connections == 0) {
>> +		clear_bit(NBD_BOUND, &config->runtime_flags);
>>  		return;
>> -	if (test_and_set_bit(NBD_DISCONNECTED, &config->runtime_flags))
>> +	}
>> +	if (test_and_set_bit(NBD_DISCONNECTED, &config->runtime_flags)) {
>> +		clear_bit(NBD_BOUND, &config->runtime_flags);
>>  		return;
>> +	}
>> 
>>  	for (i = 0; i < config->num_connections; i++) {
>>  		struct nbd_sock *nsock = config->socks[i];
>> @@ -944,7 +948,7 @@ static int nbd_reconnect_socket(struct nbd_device
>> *nbd, unsigned long arg)
>>  		sockfd_put(old);
>> 
>>  		clear_bit(NBD_DISCONNECTED, &config->runtime_flags);
>> -
>> +		clear_bit(NBD_BOUND, &config->runtime_flags);
>>  		/* We take the tx_mutex in an error path in the recv_work, so we
>>  		 * need to queue_work outside of the tx_mutex.
>>  		 */
>> @@ -1020,6 +1024,7 @@ static int nbd_disconnect(struct nbd_device 
>> *nbd)
>>  	dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
>>  	set_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags);
>>  	send_disconnects(nbd);
>> +	clear_bit(NBD_BOUND, &config->runtime_flags);
>>  	return 0;
>>  }

Re: [PATCH] nbd:clear NBD_BOUND flag when NBD connection is closed

[Josef Bacik]

On Wed, Apr 03, 2019 at 12:13:53PM -0500, Adriana Kobylak wrote:
> Adding Josef (updated email address in the maintainers file).
> 
> On 2018-12-13 08:21, Adriana Kobylak wrote:
> > On 2018-12-11 00:17, medadyoung@gmail.com wrote:
> > > From: Medad <medadyoung@gmail.com>
> > > 
> > >     If we do NOT clear NBD_BOUND flag when NBD connection is closed,
> > >     then the original NBD device could not be used again.
> > > 
> > > Signed-off-by: Medad <medadyoung@gmail.com>

This doesn't sound right, this is just making sure we don't use the IOCTL
configuration stuff with the netlink stuff.  Once the disconnect happens the
configuration should go away and it doesn't matter anymore.  What are you doing
to reproduce this problem?  Thanks,

Josef

Re: [PATCH] nbd:clear NBD_BOUND flag when NBD connection is closed

[Adriana Kobylak]

On 2019-04-03 12:49, Josef Bacik wrote:
> On Wed, Apr 03, 2019 at 12:13:53PM -0500, Adriana Kobylak wrote:
>> Adding Josef (updated email address in the maintainers file).
>> 
>> On 2018-12-13 08:21, Adriana Kobylak wrote:
>> > On 2018-12-11 00:17, medadyoung@gmail.com wrote:
>> > > From: Medad <medadyoung@gmail.com>
>> > >
>> > >     If we do NOT clear NBD_BOUND flag when NBD connection is closed,
>> > >     then the original NBD device could not be used again.
>> > >
>> > > Signed-off-by: Medad <medadyoung@gmail.com>
> 
> This doesn't sound right, this is just making sure we don't use the 
> IOCTL
> configuration stuff with the netlink stuff.  Once the disconnect 
> happens the
> configuration should go away and it doesn't matter anymore.  What are 
> you doing
> to reproduce this problem?  Thanks,
> 
> Josef

I'm not seeing an issue now that we've moved to a new version of Yocto 
containing
NBD 3.17. For reference we were reproducing by setting up a virtual 
media device
on a BMC (https://github.com/openbmc/jsnbd).
We can close this patch request unless Medad still sees an issue in his 
environment.