Re: [Qemu-devel] [PATCH COLO v4 08/15] NBD client: implement block driver interfaces to connect/disconnect NBD server

[Wen Congyang <wency@cn.fujitsu.com>]

On 05/14/2015 04:16 PM, Gonglei wrote:
> On 2015/5/8 17:16, Wen Congyang wrote:
>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
>> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
>> ---
>>  block/nbd.c | 65 ++++++++++++++++++++++++++++++++++++++++++++-----------------
>>  1 file changed, 47 insertions(+), 18 deletions(-)
>>
>> diff --git a/block/nbd.c b/block/nbd.c
>> index 2176186..0624232 100644
>> --- a/block/nbd.c
>> +++ b/block/nbd.c
>> @@ -44,6 +44,8 @@
>>  typedef struct BDRVNBDState {
>>      NbdClientSession client;
>>      QemuOpts *socket_opts;
>> +    char *export;
>> +    bool connected;
>>  } BDRVNBDState;
>>  
>>  static int nbd_parse_uri(const char *filename, QDict *options)
>> @@ -254,34 +256,55 @@ static int nbd_establish_connection(BlockDriverState *bs, Error **errp)
>>      return sock;
>>  }
>>  
>> -static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
>> -                    Error **errp)
>> +static void nbd_connect_server(BlockDriverState *bs, Error **errp)
>>  {
>>      BDRVNBDState *s = bs->opaque;
>> -    char *export = NULL;
>> -    int result, sock;
>> -    Error *local_err = NULL;
>> -
>> -    /* Pop the config into our state object. Exit if invalid. */
>> -    nbd_config(s, options, &export, &local_err);
>> -    if (local_err) {
>> -        error_propagate(errp, local_err);
>> -        return -EINVAL;
>> -    }
>> +    int sock;
>>  
>>      /* establish TCP connection, return error if it fails
>>       * TODO: Configurable retry-until-timeout behaviour.
>>       */
>>      sock = nbd_establish_connection(bs, errp);
>>      if (sock < 0) {
>> -        g_free(export);
>> -        return sock;
>> +        return;
>>      }
>>  
>>      /* NBD handshake */
>> -    result = nbd_client_init(bs, sock, export, errp);
>> -    g_free(export);
>> -    return result;
>> +    nbd_client_init(bs, sock, s->export, errp);
>> +
>> +    s->connected = true;
>> +}
>> +
>> +static void nbd_disconnect_server(BlockDriverState *bs)
>> +{
>> +    BDRVNBDState *s = bs->opaque;
>> +
>> +    if (s->connected) {
>> +        nbd_client_close(bs);
>> +        s->connected = false;
>> +    }
>> +}
>> +
>> +static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
>> +                    Error **errp)
>> +{
>> +    BDRVNBDState *s = bs->opaque;
>> +    Error *local_err = NULL;
>> +
>> +    /* Pop the config into our state object. Exit if invalid. */
>> +    nbd_config(s, options, &s->export, &local_err);
>> +    if (local_err) {
>> +        error_propagate(errp, local_err);
>> +        return -EINVAL;
>> +    }
>> +
>> +    nbd_connect_server(bs, &local_err);
>> +    if (local_err) {
>> +        error_propagate(errp, local_err);
>> +        return -EINVAL;
>> +    }
>> +
>> +    return 0;
>>  }
>>  
>>  static int nbd_co_readv(BlockDriverState *bs, int64_t sector_num,
>> @@ -318,7 +341,7 @@ static void nbd_close(BlockDriverState *bs)
>>      BDRVNBDState *s = bs->opaque;
>>  
>>      qemu_opts_del(s->socket_opts);
>> -    nbd_client_close(bs);
>> +    nbd_disconnect_server(bs);
> 
> We should free s->export here, right?

Yes. Will fix it in the next version.

Thanks
Wen Congyang

> 
> Regards,
> -Gonglei
> 
>>  }
>>  
>>  static int64_t nbd_getlength(BlockDriverState *bs)
>> @@ -400,6 +423,8 @@ static BlockDriver bdrv_nbd = {
>>      .bdrv_detach_aio_context    = nbd_detach_aio_context,
>>      .bdrv_attach_aio_context    = nbd_attach_aio_context,
>>      .bdrv_refresh_filename      = nbd_refresh_filename,
>> +    .bdrv_connect               = nbd_connect_server,
>> +    .bdrv_disconnect            = nbd_disconnect_server,
>>  };
>>  
>>  static BlockDriver bdrv_nbd_tcp = {
>> @@ -418,6 +443,8 @@ static BlockDriver bdrv_nbd_tcp = {
>>      .bdrv_detach_aio_context    = nbd_detach_aio_context,
>>      .bdrv_attach_aio_context    = nbd_attach_aio_context,
>>      .bdrv_refresh_filename      = nbd_refresh_filename,
>> +    .bdrv_connect               = nbd_connect_server,
>> +    .bdrv_disconnect            = nbd_disconnect_server,
>>  };
>>  
>>  static BlockDriver bdrv_nbd_unix = {
>> @@ -436,6 +463,8 @@ static BlockDriver bdrv_nbd_unix = {
>>      .bdrv_detach_aio_context    = nbd_detach_aio_context,
>>      .bdrv_attach_aio_context    = nbd_attach_aio_context,
>>      .bdrv_refresh_filename      = nbd_refresh_filename,
>> +    .bdrv_connect               = nbd_connect_server,
>> +    .bdrv_disconnect            = nbd_disconnect_server,
>>  };
>>  
>>  static void bdrv_nbd_init(void)
>>
> 
> 
> .
>