[PATCH v6 1/1] NFSD: move accumulated callback ops to per-net namespace

[PATCH v6 1/1] NFSD: move accumulated callback ops to per-net namespace

[Dai Ngo]

The RPC statistics for the NFSD fore channel are tracked per network
namespace, but the backchannel (callback) RPC statistics are currently
maintained globally. This causes statistics to be shared across network
namespaces and can produce misleading results when nfsd is run in
containers.

Move the accumulated backchannel/callback RPC statistics into
per-network-namespace storage so each netns maintains independent
counters.

This change only relocates the accounting. User-facing retrieval and
display of these per-netns callback statistics will be added in a
follow-up patch.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/netns.h        |  5 +++
 fs/nfsd/nfs4callback.c | 75 ++++++++++++++++++++++--------------------
 fs/nfsd/nfsctl.c       | 11 +++++++
 fs/nfsd/state.h        |  2 ++
 4 files changed, 58 insertions(+), 35 deletions(-)

v2:
  . free memory allocated for nn->nfsd_cb_version4.counts in
    nfsd_net_cb_stats_init() on error in nfsd_net_init().
v3:
  . reword commit message. 
  . fix initialization of nn->nfsd_cb_program.nrvers.
v4:
  . fix merge conflict in nfsd_net_exit in nfsd-testing branch.
v5:
  . restore commit message to the original in v1
v6:
  . put the call nfsd_net_cb_stats_init and nfsd_net_cb_stats_shutdown
    under CONFIG_NFSD_V4.

  . reword commit message to clarify the intention of the patch.

diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index 6ad3fe5d7e12..c101bf2c24c2 100644
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h
@@ -228,6 +228,11 @@ struct nfsd_net {
 	struct list_head	local_clients;
 #endif
 	siphash_key_t		*fh_key;
+
+	struct rpc_version	nfsd_cb_version4;
+	const struct rpc_version *nfsd_cb_versions[2];
+	struct rpc_program	nfsd_cb_program;
+	struct rpc_stat		nfsd_cb_stat;
 };
 
 /* Simple check to find out if a given net was properly initialized */
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index aea8bdd2fdc4..759f24657c34 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -1016,7 +1016,7 @@ static int nfs4_xdr_dec_cb_offload(struct rpc_rqst *rqstp,
 	.p_decode  = nfs4_xdr_dec_##restype,				\
 	.p_arglen  = NFS4_enc_##argtype##_sz,				\
 	.p_replen  = NFS4_dec_##restype##_sz,				\
-	.p_statidx = NFSPROC4_CB_##call,				\
+	.p_statidx = NFSPROC4_CLNT_##proc,				\
 	.p_name    = #proc,						\
 }
 
@@ -1032,40 +1032,7 @@ static const struct rpc_procinfo nfs4_cb_procedures[] = {
 	PROC(CB_GETATTR,	COMPOUND,	cb_getattr,	cb_getattr),
 };
 
-static unsigned int nfs4_cb_counts[ARRAY_SIZE(nfs4_cb_procedures)];
-static const struct rpc_version nfs_cb_version4 = {
-/*
- * Note on the callback rpc program version number: despite language in rfc
- * 5661 section 18.36.3 requiring servers to use 4 in this field, the
- * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
- * in practice that appears to be what implementations use.  The section
- * 18.36.3 language is expected to be fixed in an erratum.
- */
-	.number			= 1,
-	.nrprocs		= ARRAY_SIZE(nfs4_cb_procedures),
-	.procs			= nfs4_cb_procedures,
-	.counts			= nfs4_cb_counts,
-};
-
-static const struct rpc_version *nfs_cb_version[2] = {
-	[1] = &nfs_cb_version4,
-};
-
-static const struct rpc_program cb_program;
-
-static struct rpc_stat cb_stats = {
-	.program		= &cb_program
-};
-
 #define NFS4_CALLBACK 0x40000000
-static const struct rpc_program cb_program = {
-	.name			= "nfs4_cb",
-	.number			= NFS4_CALLBACK,
-	.nrvers			= ARRAY_SIZE(nfs_cb_version),
-	.version		= nfs_cb_version,
-	.stats			= &cb_stats,
-	.pipe_dir_name		= "nfsd4_cb",
-};
 
 static int max_cb_time(struct net *net)
 {
@@ -1152,14 +1119,15 @@ static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *c
 		.addrsize	= conn->cb_addrlen,
 		.saddress	= (struct sockaddr *) &conn->cb_saddr,
 		.timeout	= &timeparms,
-		.program	= &cb_program,
 		.version	= 1,
 		.flags		= (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 		.cred		= current_cred(),
 	};
 	struct rpc_clnt *client;
 	const struct cred *cred;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
 
+	args.program = &nn->nfsd_cb_program;
 	if (clp->cl_minorversion == 0) {
 		if (!clp->cl_cred.cr_principal &&
 		    (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5)) {
@@ -1786,3 +1754,40 @@ bool nfsd4_run_cb(struct nfsd4_callback *cb)
 		nfsd41_cb_inflight_end(clp);
 	return queued;
 }
+
+void nfsd_net_cb_stats_shutdown(struct nfsd_net *nn)
+{
+	kfree(nn->nfsd_cb_version4.counts);
+}
+
+int nfsd_net_cb_stats_init(struct nfsd_net *nn)
+{
+	nn->nfsd_cb_version4.counts = kzalloc_objs(unsigned int,
+			ARRAY_SIZE(nfs4_cb_procedures), GFP_KERNEL);
+	if (!nn->nfsd_cb_version4.counts)
+		return -ENOMEM;
+	/*
+	 * Note on the callback rpc program version number: despite language
+	 * in rfc 5661 section 18.36.3 requiring servers to use 4 in this
+	 * field, the official xdr descriptions for both 4.0 and 4.1 specify
+	 * version 1, and in practice that appears to be what implementations
+	 * use. The section 18.36.3 language is expected to be fixed in an
+	 * erratum.
+	 */
+	nn->nfsd_cb_version4.number = 1;
+
+	nn->nfsd_cb_version4.nrprocs = ARRAY_SIZE(nfs4_cb_procedures);
+	nn->nfsd_cb_version4.procs = nfs4_cb_procedures;
+	nn->nfsd_cb_versions[1] = &nn->nfsd_cb_version4;
+
+	memset(&nn->nfsd_cb_stat, 0, sizeof(nn->nfsd_cb_stat));
+	nn->nfsd_cb_program.name = "nfs4_cb";
+	nn->nfsd_cb_program.number = NFS4_CALLBACK;
+	nn->nfsd_cb_program.nrvers = ARRAY_SIZE(nn->nfsd_cb_versions);
+	nn->nfsd_cb_program.version = &nn->nfsd_cb_versions[0];
+	nn->nfsd_cb_program.pipe_dir_name = "nfsd4_cb";
+	nn->nfsd_cb_program.stats = &nn->nfsd_cb_stat;
+	nn->nfsd_cb_stat.program = &nn->nfsd_cb_program;
+
+	return 0;
+}
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 14d9458aeff0..ce69bdccbb48 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -2216,6 +2216,11 @@ static __net_init int nfsd_net_init(struct net *net)
 	int retval;
 	int i;
 
+#ifdef CONFIG_NFSD_V4
+	retval = nfsd_net_cb_stats_init(nn);
+	if (retval)
+		return retval;
+#endif
 	retval = nfsd_export_init(net);
 	if (retval)
 		goto out_export_error;
@@ -2256,6 +2261,9 @@ static __net_init int nfsd_net_init(struct net *net)
 out_idmap_error:
 	nfsd_export_shutdown(net);
 out_export_error:
+#ifdef CONFIG_NFSD_V4
+	nfsd_net_cb_stats_shutdown(nn);
+#endif
 	return retval;
 }
 
@@ -2286,6 +2294,9 @@ static __net_exit void nfsd_net_exit(struct net *net)
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 
 	kfree_sensitive(nn->fh_key);
+#ifdef CONFIG_NFSD_V4
+	nfsd_net_cb_stats_shutdown(nn);
+#endif
 	nfsd_proc_stat_shutdown(net);
 	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
 	nfsd_idmap_shutdown(net);
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 9b05462da4cc..490193c1877d 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -895,4 +895,6 @@ struct nfsd4_get_dir_delegation;
 struct nfs4_delegation *nfsd_get_dir_deleg(struct nfsd4_compound_state *cstate,
 						struct nfsd4_get_dir_delegation *gdd,
 						struct nfsd_file *nf);
+int nfsd_net_cb_stats_init(struct nfsd_net *nn);
+void nfsd_net_cb_stats_shutdown(struct nfsd_net *nn);
 #endif   /* NFSD4_STATE_H */
-- 
2.47.3

Re: [PATCH v6 1/1] NFSD: move accumulated callback ops to per-net namespace

[Chuck Lever]

On Thu, Mar 12, 2026, at 8:14 PM, Dai Ngo wrote:
> The RPC statistics for the NFSD fore channel are tracked per network
> namespace, but the backchannel (callback) RPC statistics are currently
> maintained globally. This causes statistics to be shared across network
> namespaces and can produce misleading results when nfsd is run in
> containers.
>
> Move the accumulated backchannel/callback RPC statistics into
> per-network-namespace storage so each netns maintains independent
> counters.
>
> This change only relocates the accounting. User-facing retrieval and
> display of these per-netns callback statistics will be added in a
> follow-up patch.
>
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
>  fs/nfsd/netns.h        |  5 +++
>  fs/nfsd/nfs4callback.c | 75 ++++++++++++++++++++++--------------------
>  fs/nfsd/nfsctl.c       | 11 +++++++
>  fs/nfsd/state.h        |  2 ++
>  4 files changed, 58 insertions(+), 35 deletions(-)
>
> v2:
>   . free memory allocated for nn->nfsd_cb_version4.counts in
>     nfsd_net_cb_stats_init() on error in nfsd_net_init().
> v3:
>   . reword commit message. 
>   . fix initialization of nn->nfsd_cb_program.nrvers.
> v4:
>   . fix merge conflict in nfsd_net_exit in nfsd-testing branch.
> v5:
>   . restore commit message to the original in v1
> v6:
>   . put the call nfsd_net_cb_stats_init and nfsd_net_cb_stats_shutdown
>     under CONFIG_NFSD_V4.
>
>   . reword commit message to clarify the intention of the patch.
>
> diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
> index 6ad3fe5d7e12..c101bf2c24c2 100644
> --- a/fs/nfsd/netns.h
> +++ b/fs/nfsd/netns.h
> @@ -228,6 +228,11 @@ struct nfsd_net {
>  	struct list_head	local_clients;
>  #endif
>  	siphash_key_t		*fh_key;
> +
> +	struct rpc_version	nfsd_cb_version4;
> +	const struct rpc_version *nfsd_cb_versions[2];
> +	struct rpc_program	nfsd_cb_program;
> +	struct rpc_stat		nfsd_cb_stat;
>  };
> 
>  /* Simple check to find out if a given net was properly initialized */
> diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
> index aea8bdd2fdc4..759f24657c34 100644
> --- a/fs/nfsd/nfs4callback.c
> +++ b/fs/nfsd/nfs4callback.c
> @@ -1016,7 +1016,7 @@ static int nfs4_xdr_dec_cb_offload(struct rpc_rqst *rqstp,
>  	.p_decode  = nfs4_xdr_dec_##restype,				\
>  	.p_arglen  = NFS4_enc_##argtype##_sz,				\
>  	.p_replen  = NFS4_dec_##restype##_sz,				\
> -	.p_statidx = NFSPROC4_CB_##call,				\
> +	.p_statidx = NFSPROC4_CLNT_##proc,				\
>  	.p_name    = #proc,						\
>  }
> 
> @@ -1032,40 +1032,7 @@ static const struct rpc_procinfo nfs4_cb_procedures[] = {
>  	PROC(CB_GETATTR,	COMPOUND,	cb_getattr,	cb_getattr),
>  };
> 
> -static unsigned int nfs4_cb_counts[ARRAY_SIZE(nfs4_cb_procedures)];
> -static const struct rpc_version nfs_cb_version4 = {
> -/*
> - * Note on the callback rpc program version number: despite language in rfc
> - * 5661 section 18.36.3 requiring servers to use 4 in this field, the
> - * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
> - * in practice that appears to be what implementations use.  The section
> - * 18.36.3 language is expected to be fixed in an erratum.
> - */
> -	.number			= 1,
> -	.nrprocs		= ARRAY_SIZE(nfs4_cb_procedures),
> -	.procs			= nfs4_cb_procedures,
> -	.counts			= nfs4_cb_counts,
> -};
> -
> -static const struct rpc_version *nfs_cb_version[2] = {
> -	[1] = &nfs_cb_version4,
> -};
> -
> -static const struct rpc_program cb_program;
> -
> -static struct rpc_stat cb_stats = {
> -	.program		= &cb_program
> -};
> -
>  #define NFS4_CALLBACK 0x40000000
> -static const struct rpc_program cb_program = {
> -	.name			= "nfs4_cb",
> -	.number			= NFS4_CALLBACK,
> -	.nrvers			= ARRAY_SIZE(nfs_cb_version),
> -	.version		= nfs_cb_version,
> -	.stats			= &cb_stats,
> -	.pipe_dir_name		= "nfsd4_cb",
> -};
> 
>  static int max_cb_time(struct net *net)
>  {
> @@ -1152,14 +1119,15 @@ static int setup_callback_client(struct 
> nfs4_client *clp, struct nfs4_cb_conn *c
>  		.addrsize	= conn->cb_addrlen,
>  		.saddress	= (struct sockaddr *) &conn->cb_saddr,
>  		.timeout	= &timeparms,
> -		.program	= &cb_program,
>  		.version	= 1,
>  		.flags		= (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
>  		.cred		= current_cred(),
>  	};
>  	struct rpc_clnt *client;
>  	const struct cred *cred;
> +	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
> 
> +	args.program = &nn->nfsd_cb_program;
>  	if (clp->cl_minorversion == 0) {
>  		if (!clp->cl_cred.cr_principal &&
>  		    (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5)) {
> @@ -1786,3 +1754,40 @@ bool nfsd4_run_cb(struct nfsd4_callback *cb)
>  		nfsd41_cb_inflight_end(clp);
>  	return queued;
>  }
> +
> +void nfsd_net_cb_stats_shutdown(struct nfsd_net *nn)
> +{
> +	kfree(nn->nfsd_cb_version4.counts);
> +}
> +
> +int nfsd_net_cb_stats_init(struct nfsd_net *nn)
> +{
> +	nn->nfsd_cb_version4.counts = kzalloc_objs(unsigned int,
> +			ARRAY_SIZE(nfs4_cb_procedures), GFP_KERNEL);
> +	if (!nn->nfsd_cb_version4.counts)
> +		return -ENOMEM;
> +	/*
> +	 * Note on the callback rpc program version number: despite language
> +	 * in rfc 5661 section 18.36.3 requiring servers to use 4 in this
> +	 * field, the official xdr descriptions for both 4.0 and 4.1 specify
> +	 * version 1, and in practice that appears to be what implementations
> +	 * use. The section 18.36.3 language is expected to be fixed in an
> +	 * erratum.
> +	 */
> +	nn->nfsd_cb_version4.number = 1;
> +
> +	nn->nfsd_cb_version4.nrprocs = ARRAY_SIZE(nfs4_cb_procedures);
> +	nn->nfsd_cb_version4.procs = nfs4_cb_procedures;
> +	nn->nfsd_cb_versions[1] = &nn->nfsd_cb_version4;
> +
> +	memset(&nn->nfsd_cb_stat, 0, sizeof(nn->nfsd_cb_stat));
> +	nn->nfsd_cb_program.name = "nfs4_cb";
> +	nn->nfsd_cb_program.number = NFS4_CALLBACK;
> +	nn->nfsd_cb_program.nrvers = ARRAY_SIZE(nn->nfsd_cb_versions);
> +	nn->nfsd_cb_program.version = &nn->nfsd_cb_versions[0];
> +	nn->nfsd_cb_program.pipe_dir_name = "nfsd4_cb";
> +	nn->nfsd_cb_program.stats = &nn->nfsd_cb_stat;
> +	nn->nfsd_cb_stat.program = &nn->nfsd_cb_program;
> +
> +	return 0;
> +}
> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> index 14d9458aeff0..ce69bdccbb48 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -2216,6 +2216,11 @@ static __net_init int nfsd_net_init(struct net *net)
>  	int retval;
>  	int i;
> 
> +#ifdef CONFIG_NFSD_V4
> +	retval = nfsd_net_cb_stats_init(nn);
> +	if (retval)
> +		return retval;
> +#endif
>  	retval = nfsd_export_init(net);
>  	if (retval)
>  		goto out_export_error;
> @@ -2256,6 +2261,9 @@ static __net_init int nfsd_net_init(struct net *net)
>  out_idmap_error:
>  	nfsd_export_shutdown(net);
>  out_export_error:
> +#ifdef CONFIG_NFSD_V4
> +	nfsd_net_cb_stats_shutdown(nn);
> +#endif
>  	return retval;
>  }
> 
> @@ -2286,6 +2294,9 @@ static __net_exit void nfsd_net_exit(struct net *net)
>  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> 
>  	kfree_sensitive(nn->fh_key);
> +#ifdef CONFIG_NFSD_V4
> +	nfsd_net_cb_stats_shutdown(nn);
> +#endif
>  	nfsd_proc_stat_shutdown(net);
>  	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
>  	nfsd_idmap_shutdown(net);
> diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
> index 9b05462da4cc..490193c1877d 100644
> --- a/fs/nfsd/state.h
> +++ b/fs/nfsd/state.h
> @@ -895,4 +895,6 @@ struct nfsd4_get_dir_delegation;
>  struct nfs4_delegation *nfsd_get_dir_deleg(struct nfsd4_compound_state *cstate,
>  						struct nfsd4_get_dir_delegation *gdd,
>  						struct nfsd_file *nf);
> +int nfsd_net_cb_stats_init(struct nfsd_net *nn);
> +void nfsd_net_cb_stats_shutdown(struct nfsd_net *nn);
>  #endif   /* NFSD4_STATE_H */
> -- 
> 2.47.3

There are at least five unaddressed previous review comments
here in v6. Since this is a simple clean-up that seems to have
stalled out, I'll fix those up and apply it.


-- 
Chuck Lever