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Date: Mon, 22 Apr 2024 07:00:18 +0200
From: Petr Vorel <pvorel@suse.cz>
To: NeilBrown <neilb@suse.de>
Cc: Chuck Lever <chuck.lever@oracle.com>, Jeff Layton <jlayton@kernel.org>,
	Olga Kornievskaia <kolga@netapp.com>, Dai Ngo <Dai.Ngo@oracle.com>,
	Tom Talpey <tom@talpey.com>, linux-nfs@vger.kernel.org
Subject: Re: [PATCH] nfsd: don't fail OP_SETCLIENTID when there are lots of
 clients.
Message-ID: <20240422050018.GA64791@pevik>
Reply-To: Petr Vorel <pvorel@suse.cz>
References: <171375175915.7600.6526208866216039031@noble.neil.brown.name>
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In-Reply-To: <171375175915.7600.6526208866216039031@noble.neil.brown.name>

Hi all,

> The calculation of how many clients the nfs server can manage is only an
> heuristic.  Triggering the laundromat to clean up old clients when we
> have more than the heuristic limit is valid, but refusing to create new
> clients is not.  Client creation should only fail if there really isn't
> enough memory available.

> This is not known to have caused a problem is production use, but
> testing of lots of clients reports an error and it is not clear that
> this error is justified.

> Signed-off-by: NeilBrown <neilb@suse.de>
> ---
>  fs/nfsd/nfs4state.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)

> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index daf83823ba48..8a40bb6a4a67 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -2223,10 +2223,9 @@ static struct nfs4_client *alloc_client(struct xdr_netobj name,
>  	struct nfs4_client *clp;
>  	int i;

> -	if (atomic_read(&nn->nfs4_client_count) >= nn->nfs4_max_clients) {
> +	if (atomic_read(&nn->nfs4_client_count) >= nn->nfs4_max_clients)
>  		mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
> -		return NULL;
> -	}

LGTM.

Reviewed-by: Petr Vorel <pvorel@suse.cz>

Kind regards,
Petr

> +
>  	clp = kmem_cache_zalloc(client_slab, GFP_KERNEL);
>  	if (clp == NULL)
>  		return NULL;