On 13.08.20 18:29, Kevin Wolf wrote:
> This adds a function to shut down all block exports, and another one to
> shut down the block exports of a single type. The latter is used for now
> when stopping the NBD server. As soon as we implement support for
> multiple NBD servers, we'll need a per-server list of exports and it
> will be replaced by a function using that.
> 
> As a side effect, the BlockExport layer has a list tracking all existing
> exports now. closed_exports loses its only user and can go away.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  include/block/export.h |  8 +++++++
>  include/block/nbd.h    |  2 --
>  block.c                |  2 +-
>  block/export/export.c  | 52 ++++++++++++++++++++++++++++++++++++++++++
>  blockdev-nbd.c         |  2 +-
>  nbd/server.c           | 34 ++++-----------------------
>  qemu-nbd.c             |  2 +-
>  7 files changed, 68 insertions(+), 34 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>

> diff --git a/block/export/export.c b/block/export/export.c
> index 9de108cbc1..675db9a8b9 100644
> --- a/block/export/export.c
> +++ b/block/export/export.c

[...]

> +/* type == BLOCK_EXPORT_TYPE__MAX for all types */
> +void blk_exp_close_all_type(BlockExportType type)
> +{
> +    BlockExport *exp, *next;
> +
> +    QLIST_FOREACH_SAFE(exp, &block_exports, next, next) {
> +        if (type != BLOCK_EXPORT_TYPE__MAX && exp->drv->type != type) {
> +            continue;
> +        }
> +        blk_exp_request_shutdown(exp);
> +    }
> +
> +    AIO_WAIT_WHILE(NULL, blk_exp_has_type(type));
> +}
> +
> +void blk_exp_close_all(void)
> +{
> +    blk_exp_close_all_type(BLOCK_EXPORT_TYPE__MAX);

What’s interesting about this is that I saw from the header file that
you added both this and the type-specific function and wondered “Why not
just pass __MAX to close_all_type() to close all?”  And then I thought
“Because that would be stupid as an external interface”.

So I see you had the same thinking.