Re: [PATCH v3 2/2] qemu-nbd: Permit --shared=0 for unlimited clients

[Nir Soffer <nsoffer@redhat.com>]

On Tue, Feb 9, 2021 at 5:28 PM Eric Blake <eblake@redhat.com> wrote:
>
> This gives us better feature parity with QMP nbd-server-start, where
> max-connections defaults to 0 for unlimited.

Sound useful

> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>  docs/tools/qemu-nbd.rst | 4 ++--
>  qemu-nbd.c              | 7 +++----
>  2 files changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/docs/tools/qemu-nbd.rst b/docs/tools/qemu-nbd.rst
> index fe41336dc550..ee862fa0bc02 100644
> --- a/docs/tools/qemu-nbd.rst
> +++ b/docs/tools/qemu-nbd.rst
> @@ -136,8 +136,8 @@ driver options if ``--image-opts`` is specified.
>  .. option:: -e, --shared=NUM
>
>    Allow up to *NUM* clients to share the device (default
> -  ``1``). Safe for readers, but for now, consistency is not
> -  guaranteed between multiple writers.
> +  ``1``), 0 for unlimited. Safe for readers, but for now,
> +  consistency is not guaranteed between multiple writers.
>
>  .. option:: -t, --persistent
>
> diff --git a/qemu-nbd.c b/qemu-nbd.c
> index 1a340ea4858d..5416509ece18 100644
> --- a/qemu-nbd.c
> +++ b/qemu-nbd.c
> @@ -328,7 +328,7 @@ static void *nbd_client_thread(void *arg)
>
>  static int nbd_can_accept(void)
>  {
> -    return state == RUNNING && nb_fds < shared;
> +    return state == RUNNING && (shared == 0 || nb_fds < shared);
>  }
>
>  static void nbd_update_server_watch(void);
> @@ -706,8 +706,8 @@ int main(int argc, char **argv)
>              device = optarg;
>              break;
>          case 'e':
>              if (qemu_strtoi(optarg, NULL, 0, &shared) < 0 ||
> -                shared < 1) {
> +                shared < 0) {
>                  error_report("Invalid shared device number '%s'", optarg);
>                  exit(EXIT_FAILURE);
>              }
> @@ -966,7 +965,7 @@ int main(int argc, char **argv)
>      if (socket_activation == 0) {
>          int backlog;
>
> -        if (persistent) {
> +        if (persistent || shared == 0) {
>              backlog = SOMAXCONN;
>          } else {
>              backlog = MIN(shared, SOMAXCONN);
> --
> 2.30.0
>

Reviewed-by: Nir Soffer <nsoffer@redhat.com>