Re: [PATCH] NFS: switch back to using kill_anon_super

[Jeff Layton <jlayton@kernel.org>]

On Thu, 2023-08-31 at 07:29 +0200, Christoph Hellwig wrote:
> NFS switch to open coding kill_anon_super in 7b14a213890a
> ("nfs: don't call bdi_unregister") to avoid the extra bdi_unregister
> call.  At that point bdi_destroy was called in nfs_free_server and
> thus it required a later freeing of the anon dev_t.  But since
> 0db10944a76b ("nfs: Convert to separately allocated bdi") the bdi has
> been free implicitly by the sb destruction, so this isn't needed
> anymore.
> 
> By not open coding kill_anon_super, nfs now inherits the fix in
> dc3216b14160 ("super: ensure valid info"), and we remove the only
> open coded version of kill_anon_super.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/nfs/super.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index 2284f749d89246..0d6473cb00cb3e 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -1339,15 +1339,13 @@ int nfs_get_tree_common(struct fs_context *fc)
>  void nfs_kill_super(struct super_block *s)
>  {
>  	struct nfs_server *server = NFS_SB(s);
> -	dev_t dev = s->s_dev;
>  
>  	nfs_sysfs_move_sb_to_server(server);
> -	generic_shutdown_super(s);
> +	kill_anon_super(s);
>  
>  	nfs_fscache_release_super_cookie(s);
>  
>  	nfs_free_server(server);
> -	free_anon_bdev(dev);
>  }
>  EXPORT_SYMBOL_GPL(nfs_kill_super);
>  

Nice. Long overdue. This also might explain why ceph was once this way
before we changed it here:

    470a5c77eac0 ceph: use kill_anon_super helper

In any case:

Reviewed-by: Jeff Layton <jlayton@kernel.org>