Re: [RFC PATCH] Revert "NFSD: Force all NFSv4.2 COPY requests to be synchronous"

[Jeff Layton <jlayton@kernel.org>]

On Wed, 2025-06-18 at 08:58 -0400, Chuck Lever wrote:
> From: Chuck Lever <chuck.lever@oracle.com>
> 
> In the past several kernel releases, we've made NFSv4.2 async copy
> reliable:
>  - The Linux NFS client and server now both implement and use the
>    NFSv4.2 OFFLOAD_STATUS operation
>  - The Linux NFS server keeps copy stateids around longer
>  - The Linux NFS client and server now both implement referring call
>    lists
> 
> And resilient against DoS:
>  - The Linux NFS server limits the number of concurrent async copy
>    operations
> 
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  fs/nfsd/nfs4proc.c | 7 -------
>  1 file changed, 7 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index f13abbb13b38..2b76a8267a4b 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1917,13 +1917,6 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>  	struct nfsd42_write_res *result;
>  	__be32 status;
>  
> -	/*
> -	 * Currently, async COPY is not reliable. Force all COPY
> -	 * requests to be synchronous to avoid client application
> -	 * hangs waiting for COPY completion.
> -	 */
> -	nfsd4_copy_set_sync(copy, true);
> -
>  	result = &copy->cp_res;
>  	nfsd_copy_write_verifier((__be32 *)&result->wr_verifier.data, nn);
>  

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