[PATCH v4 0/4] nfsd/sunrpc: convert nfsstat server-side interfaces to use netlink

[PATCH v4 0/4] nfsd/sunrpc: convert nfsstat server-side interfaces to use netlink

[Jeff Layton]

This version just fixes an error handling bug that Sashiko noticed.

The nfsstat tool currently scrapes /proc/net/rpc/nfsd for server
statistics. This procfs interface has several limitations: the
counters are global (not network-namespace-aware), the format is
fragile to parse, and it cannot be extended without breaking
existing parsers.

This series adds per-network-namespace procedure call counts to
the sunrpc layer and exposes them through a new netlink handler
in the nfsd generic netlink family, allowing nfsstat to retrieve
server statistics via netlink with a procfs fallback for older
kernels.

Patch 1 adds per-netns per-procedure percpu call count arrays to
struct svc_stat, allocated alongside the nfsd_net lifecycle.

Patch 2 switches svc_seq_show() to read from the per-netns
counters, making /proc/net/rpc/nfsd namespace-aware. Note that this
is a behavior change, but I think it's a desirable one.

Patch 3 implements the server-stats-get netlink dump handler,
streaming reply-cache, filehandle, IO, network, and RPC
statistics plus per-version and per-operation procedure counts.

Patch 4 removes the now-unused global svc_version vs_count
percpu arrays from nfsd, lockd, and the NFS client callback
service.

I'll also be sending an nfs-utils patch to convert nfsstat to use the
new interfaces.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
Changes in v4:
- Ensure error is returned when nla_put_*() calls fail
- Link to v3: https://lore.kernel.org/r/20260609-exportd-netlink-v3-0-aa5508a5bb1d@kernel.org

Changes in v3:
- Only increment per-net stats for the "primary" program
- Link to v2: https://lore.kernel.org/r/20260525-exportd-netlink-v2-0-40003fed450c@kernel.org

---
Jeff Layton (4):
      sunrpc: add per-netns per-procedure call counts to svc_stat
      sunrpc: use per-net counts in svc_seq_show()
      nfsd: implement server-stats-get netlink handler
      sunrpc: remove unused svc_version vs_count field

 Documentation/netlink/specs/nfsd.yaml | 105 +++++++++++++++++
 fs/lockd/svc4proc.c                   |   4 -
 fs/lockd/svcproc.c                    |   7 --
 fs/nfs/callback_xdr.c                 |   6 -
 fs/nfsd/localio.c                     |   3 -
 fs/nfsd/netlink.c                     |   5 +
 fs/nfsd/netlink.h                     |   2 +
 fs/nfsd/nfs2acl.c                     |   3 -
 fs/nfsd/nfs3acl.c                     |   3 -
 fs/nfsd/nfs3proc.c                    |   3 -
 fs/nfsd/nfs4proc.c                    |   3 -
 fs/nfsd/nfsctl.c                      | 214 +++++++++++++++++++++++++++++++++-
 fs/nfsd/nfsproc.c                     |   3 -
 include/linux/sunrpc/stats.h          |   6 +
 include/linux/sunrpc/svc.h            |   1 -
 include/uapi/linux/nfsd_netlink.h     |  35 ++++++
 net/sunrpc/stats.c                    |  56 ++++++++-
 net/sunrpc/svc.c                      |   9 +-
 18 files changed, 428 insertions(+), 40 deletions(-)
---
base-commit: c13952992d5459add7732eb4876eebfeec03af58
change-id: 20260316-exportd-netlink-1c9fb52536e3

Best regards,
-- 
Jeff Layton <jlayton@kernel.org>

[PATCH v4 1/4] sunrpc: add per-netns per-procedure call counts to svc_stat

[Jeff Layton]

The existing per-procedure call counts live in global
svc_version->vs_count[] arrays which are not network-namespace-aware.
Add per-netns equivalents in struct svc_stat so the upcoming netlink
stats interface can return namespace-scoped statistics.

Add a vs_count pointer array to struct svc_stat, along with
svc_stat_alloc_counts() and svc_stat_free_counts() helpers to manage
per-version percpu call count arrays.

Increment the per-net counter alongside the global one in
svc_generic_init_request(). Call the alloc/free helpers from
nfsd_net_init() and nfsd_net_exit().

Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/nfsd/nfsctl.c             |  8 ++++++-
 include/linux/sunrpc/stats.h |  6 +++++
 net/sunrpc/stats.c           | 54 ++++++++++++++++++++++++++++++++++++++++++++
 net/sunrpc/svc.c             |  8 +++++++
 4 files changed, 75 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index caf59421f8f4..601301e34fc7 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -2514,9 +2514,12 @@ static __net_init int nfsd_net_init(struct net *net)
 
 	memset(&nn->nfsd_svcstats, 0, sizeof(nn->nfsd_svcstats));
 	nn->nfsd_svcstats.program = &nfsd_programs[0];
+	retval = svc_stat_alloc_counts(&nn->nfsd_svcstats);
+	if (retval)
+		goto out_proc_error;
 	if (!nfsd_proc_stat_init(net)) {
 		retval = -ENOMEM;
-		goto out_proc_error;
+		goto out_svcstats_error;
 	}
 
 	for (i = 0; i < sizeof(nn->nfsd_versions); i++)
@@ -2534,6 +2537,8 @@ static __net_init int nfsd_net_init(struct net *net)
 #endif
 	return 0;
 
+out_svcstats_error:
+	svc_stat_free_counts(&nn->nfsd_svcstats);
 out_proc_error:
 	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
 out_repcache_error:
@@ -2574,6 +2579,7 @@ static __net_exit void nfsd_net_exit(struct net *net)
 	kfree_sensitive(nn->fh_key);
 	nfsd_net_cb_shutdown(nn);
 	nfsd_proc_stat_shutdown(net);
+	svc_stat_free_counts(&nn->nfsd_svcstats);
 	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
 	nfsd_idmap_shutdown(net);
 	nfsd_export_shutdown(net);
diff --git a/include/linux/sunrpc/stats.h b/include/linux/sunrpc/stats.h
index 3ce1550d1beb..087ade905e29 100644
--- a/include/linux/sunrpc/stats.h
+++ b/include/linux/sunrpc/stats.h
@@ -37,9 +37,15 @@ struct svc_stat {
 				rpcbadfmt,
 				rpcbadauth,
 				rpcbadclnt;
+
+	/* Per-version per-procedure call counts (per-cpu, per-netns) */
+	unsigned long __percpu	**vs_count;
 };
 
 struct net;
+int			svc_stat_alloc_counts(struct svc_stat *statp);
+void			svc_stat_free_counts(struct svc_stat *statp);
+
 #ifdef CONFIG_PROC_FS
 int			rpc_proc_init(struct net *);
 void			rpc_proc_exit(struct net *);
diff --git a/net/sunrpc/stats.c b/net/sunrpc/stats.c
index 7093e18ac26c..5bcecd2919b1 100644
--- a/net/sunrpc/stats.c
+++ b/net/sunrpc/stats.c
@@ -116,6 +116,60 @@ void svc_seq_show(struct seq_file *seq, const struct svc_stat *statp)
 }
 EXPORT_SYMBOL_GPL(svc_seq_show);
 
+/**
+ * svc_stat_alloc_counts - allocate per-netns per-version call count arrays
+ * @statp: svc_stat whose vs_count arrays should be allocated
+ *
+ * statp->program must be set before calling this.
+ *
+ * Returns zero on success, or a negative errno otherwise.
+ */
+int svc_stat_alloc_counts(struct svc_stat *statp)
+{
+	struct svc_program *prog = statp->program;
+	unsigned int i;
+
+	statp->vs_count = kcalloc(prog->pg_nvers,
+				  sizeof(unsigned long __percpu *),
+				  GFP_KERNEL);
+	if (!statp->vs_count)
+		return -ENOMEM;
+
+	for (i = 0; i < prog->pg_nvers; i++) {
+		if (!prog->pg_vers[i])
+			continue;
+		statp->vs_count[i] = __alloc_percpu(prog->pg_vers[i]->vs_nproc *
+					    sizeof(unsigned long),
+					    sizeof(unsigned long));
+		if (!statp->vs_count[i])
+			goto err;
+	}
+	return 0;
+err:
+	svc_stat_free_counts(statp);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(svc_stat_alloc_counts);
+
+/**
+ * svc_stat_free_counts - free per-netns per-version call count arrays
+ * @statp: svc_stat whose vs_count arrays should be freed
+ */
+void svc_stat_free_counts(struct svc_stat *statp)
+{
+	struct svc_program *prog = statp->program;
+	unsigned int i;
+
+	if (!statp->vs_count)
+		return;
+
+	for (i = 0; i < prog->pg_nvers; i++)
+		free_percpu(statp->vs_count[i]);
+	kfree(statp->vs_count);
+	statp->vs_count = NULL;
+}
+EXPORT_SYMBOL_GPL(svc_stat_free_counts);
+
 /**
  * rpc_alloc_iostats - allocate an rpc_iostats structure
  * @clnt: RPC program, version, and xprt
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index dd80a2eaaa74..f748004835f7 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1438,6 +1438,14 @@ svc_generic_init_request(struct svc_rqst *rqstp,
 	/* Bump per-procedure stats counter */
 	this_cpu_inc(versp->vs_count[rqstp->rq_proc]);
 
+	/* Bump per-net per-procedure stats counter */
+	if (rqstp->rq_server->sv_stats &&
+	    rqstp->rq_server->sv_stats->program == progp &&
+	    rqstp->rq_server->sv_stats->vs_count &&
+	    rqstp->rq_server->sv_stats->vs_count[rqstp->rq_vers])
+		this_cpu_inc(rqstp->rq_server->sv_stats->vs_count
+				[rqstp->rq_vers][rqstp->rq_proc]);
+
 	ret->dispatch = versp->vs_dispatch;
 	return rpc_success;
 err_bad_vers:

-- 
2.54.0

[PATCH v4 2/4] sunrpc: use per-net counts in svc_seq_show()

[Jeff Layton]

Update svc_seq_show() to read from the per-netns
statp->vs_count[] arrays instead of the global
svc_version->vs_count[].

The only caller is nfsd, which always allocates vs_count via
svc_stat_alloc_counts() in nfsd_net_init(), so the per-netns
arrays are always available.

This makes /proc/net/rpc/nfsd report per-network-namespace
procedure call counts.

Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 net/sunrpc/stats.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sunrpc/stats.c b/net/sunrpc/stats.c
index 5bcecd2919b1..fc2db251dfa0 100644
--- a/net/sunrpc/stats.c
+++ b/net/sunrpc/stats.c
@@ -108,7 +108,7 @@ void svc_seq_show(struct seq_file *seq, const struct svc_stat *statp)
 		for (j = 0; j < vers->vs_nproc; j++) {
 			count = 0;
 			for_each_possible_cpu(k)
-				count += per_cpu(vers->vs_count[j], k);
+				count += per_cpu(statp->vs_count[i][j], k);
 			seq_printf(seq, " %lu", count);
 		}
 		seq_putc(seq, '\n');

-- 
2.54.0

[PATCH v4 3/4] nfsd: implement server-stats-get netlink handler

[Jeff Layton]

Implement nfsd_nl_server_stats_get_dumpit() which exposes the
NFS server statistics currently available via /proc/net/rpc/nfsd
through the nfsd generic netlink family.

The handler uses a dump operation to stream statistics across
multiple netlink messages:

  - First message: all scalar stats (reply cache, filehandle,
    IO, network, RPC) plus per-version procedure counts
    (proc2/3/4-ops) using per-netns vs_count arrays.

  - Subsequent messages: NFSv4 per-operation counts
    (proc4ops-ops), one entry per message, using cb->args[0]
    to track the current operation index across dump calls.

This allows nfsstat to retrieve server statistics via netlink
with a procfs fallback for older kernels.

Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 Documentation/netlink/specs/nfsd.yaml | 105 +++++++++++++++++
 fs/nfsd/netlink.c                     |   5 +
 fs/nfsd/netlink.h                     |   2 +
 fs/nfsd/nfsctl.c                      | 206 ++++++++++++++++++++++++++++++++++
 include/uapi/linux/nfsd_netlink.h     |  35 ++++++
 5 files changed, 353 insertions(+)

diff --git a/Documentation/netlink/specs/nfsd.yaml b/Documentation/netlink/specs/nfsd.yaml
index 8f36fadd68f7..2a89d355ee7b 100644
--- a/Documentation/netlink/specs/nfsd.yaml
+++ b/Documentation/netlink/specs/nfsd.yaml
@@ -330,6 +330,86 @@ attribute-sets:
           of which client holds the state. Intended for use after
           all clients have been unexported from a given path,
           enabling the underlying filesystem to be unmounted.
+  -
+    name: server-proc-entry
+    attributes:
+      -
+        name: op
+        type: u32
+      -
+        name: count
+        type: u64
+      -
+        name: pad
+        type: pad
+  -
+    name: server-stats
+    attributes:
+      -
+        name: rc-hits
+        type: u64
+      -
+        name: rc-misses
+        type: u64
+      -
+        name: rc-nocache
+        type: u64
+      -
+        name: pad
+        type: pad
+      -
+        name: fh-stale
+        type: u64
+      -
+        name: io-read
+        type: u64
+      -
+        name: io-write
+        type: u64
+      -
+        name: netcnt
+        type: u32
+      -
+        name: netudpcnt
+        type: u32
+      -
+        name: nettcpcnt
+        type: u32
+      -
+        name: nettcpconn
+        type: u32
+      -
+        name: rpccnt
+        type: u32
+      -
+        name: rpcbadfmt
+        type: u32
+      -
+        name: rpcbadauth
+        type: u32
+      -
+        name: rpcbadclnt
+        type: u32
+      -
+        name: proc2-ops
+        type: nest
+        nested-attributes: server-proc-entry
+        multi-attr: true
+      -
+        name: proc3-ops
+        type: nest
+        nested-attributes: server-proc-entry
+        multi-attr: true
+      -
+        name: proc4-ops
+        type: nest
+        nested-attributes: server-proc-entry
+        multi-attr: true
+      -
+        name: proc4ops-ops
+        type: nest
+        nested-attributes: server-proc-entry
+        multi-attr: true
 
 operations:
   list:
@@ -516,6 +596,31 @@ operations:
         request:
           attributes:
             - path
+    -
+      name: server-stats-get
+      doc: dump NFS server statistics
+      attribute-set: server-stats
+      dump:
+        reply:
+          attributes:
+            - rc-hits
+            - rc-misses
+            - rc-nocache
+            - fh-stale
+            - io-read
+            - io-write
+            - netcnt
+            - netudpcnt
+            - nettcpcnt
+            - nettcpconn
+            - rpccnt
+            - rpcbadfmt
+            - rpcbadauth
+            - rpcbadclnt
+            - proc2-ops
+            - proc3-ops
+            - proc4-ops
+            - proc4ops-ops
 
 mcast-groups:
   list:
diff --git a/fs/nfsd/netlink.c b/fs/nfsd/netlink.c
index fbee3676d253..eba8b353f412 100644
--- a/fs/nfsd/netlink.c
+++ b/fs/nfsd/netlink.c
@@ -225,6 +225,11 @@ static const struct genl_split_ops nfsd_nl_ops[] = {
 		.maxattr	= NFSD_A_UNLOCK_EXPORT_PATH,
 		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
 	},
+	{
+		.cmd	= NFSD_CMD_SERVER_STATS_GET,
+		.dumpit	= nfsd_nl_server_stats_get_dumpit,
+		.flags	= GENL_CMD_CAP_DUMP,
+	},
 };
 
 static const struct genl_multicast_group nfsd_nl_mcgrps[] = {
diff --git a/fs/nfsd/netlink.h b/fs/nfsd/netlink.h
index af41aa0d4a65..027e2953db26 100644
--- a/fs/nfsd/netlink.h
+++ b/fs/nfsd/netlink.h
@@ -42,6 +42,8 @@ int nfsd_nl_cache_flush_doit(struct sk_buff *skb, struct genl_info *info);
 int nfsd_nl_unlock_ip_doit(struct sk_buff *skb, struct genl_info *info);
 int nfsd_nl_unlock_filesystem_doit(struct sk_buff *skb, struct genl_info *info);
 int nfsd_nl_unlock_export_doit(struct sk_buff *skb, struct genl_info *info);
+int nfsd_nl_server_stats_get_dumpit(struct sk_buff *skb,
+				    struct netlink_callback *cb);
 
 enum {
 	NFSD_NLGRP_NONE,
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 601301e34fc7..f165f0023c70 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -2329,6 +2329,212 @@ int nfsd_nl_cache_flush_doit(struct sk_buff *skb, struct genl_info *info)
 	return 0;
 }
 
+static int nfsd_nl_fill_proc_ops(struct sk_buff *skb, int attr,
+				 unsigned long __percpu *counts,
+				 unsigned int nproc)
+{
+	struct nlattr *nest;
+	unsigned int j;
+	int k;
+
+	for (j = 0; j < nproc; j++) {
+		unsigned long count = 0;
+
+		for_each_possible_cpu(k)
+			count += per_cpu(counts[j], k);
+
+		nest = nla_nest_start(skb, attr);
+		if (!nest)
+			return -EMSGSIZE;
+		if (nla_put_u32(skb, NFSD_A_SERVER_PROC_ENTRY_OP, j) ||
+		    nla_put_u64_64bit(skb, NFSD_A_SERVER_PROC_ENTRY_COUNT,
+				      count, NFSD_A_SERVER_PROC_ENTRY_PAD)) {
+			nla_nest_cancel(skb, nest);
+			return -EMSGSIZE;
+		}
+		nla_nest_end(skb, nest);
+	}
+
+	return 0;
+}
+
+/**
+ * nfsd_nl_server_stats_get_dumpit - dump NFS server statistics
+ * @skb: reply buffer
+ * @cb: netlink metadata and command arguments
+ *
+ * cb->args[0] tracks the current NFSv4 operation index for proc4ops.
+ * A value of 0 means we haven't started yet. We emit all scalar stats
+ * and per-version procedure counts in the first message, then emit
+ * proc4ops entries filling as many as will fit per message.
+ *
+ * Returns the size of the reply or a negative errno.
+ */
+int nfsd_nl_server_stats_get_dumpit(struct sk_buff *skb,
+				    struct netlink_callback *cb)
+{
+	struct net *net = sock_net(skb->sk);
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct svc_stat *statp = &nn->nfsd_svcstats;
+	struct svc_program *prog = statp->program;
+	int start = cb->args[0];
+	void *hdr;
+
+	/*
+	 * cb->args[0] == 0: first call, emit scalar stats + procN counts
+	 * cb->args[0] > 0: emit proc4ops entries starting from args[0] - 1
+	 * cb->args[0] < 0: done
+	 */
+	if (start < 0)
+		return 0;
+
+	if (start == 0) {
+		hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
+				  cb->nlh->nlmsg_seq, &nfsd_nl_family,
+				  NLM_F_MULTI, NFSD_CMD_SERVER_STATS_GET);
+		if (!hdr)
+			return -ENOBUFS;
+
+		/* Reply cache stats */
+		{
+			u64 hits, misses, nocache;
+
+			hits = percpu_counter_sum_positive(&nn->counter[NFSD_STATS_RC_HITS]);
+			misses = percpu_counter_sum_positive(&nn->counter[NFSD_STATS_RC_MISSES]);
+			nocache = percpu_counter_sum_positive(&nn->counter[NFSD_STATS_RC_NOCACHE]);
+			if (nla_put_u64_64bit(skb, NFSD_A_SERVER_STATS_RC_HITS,
+					hits, NFSD_A_SERVER_STATS_PAD) ||
+			    nla_put_u64_64bit(skb, NFSD_A_SERVER_STATS_RC_MISSES,
+					misses, NFSD_A_SERVER_STATS_PAD) ||
+			    nla_put_u64_64bit(skb, NFSD_A_SERVER_STATS_RC_NOCACHE,
+					nocache, NFSD_A_SERVER_STATS_PAD))
+				goto err_cancel;
+		}
+
+		/* Filehandle stats */
+		if (nla_put_u64_64bit(skb, NFSD_A_SERVER_STATS_FH_STALE,
+				percpu_counter_sum_positive(&nn->counter[NFSD_STATS_FH_STALE]),
+				NFSD_A_SERVER_STATS_PAD))
+			goto err_cancel;
+
+		/* IO stats */
+		{
+			u64 rd, wr;
+
+			rd = percpu_counter_sum_positive(&nn->counter[NFSD_STATS_IO_READ]);
+			wr = percpu_counter_sum_positive(&nn->counter[NFSD_STATS_IO_WRITE]);
+			if (nla_put_u64_64bit(skb, NFSD_A_SERVER_STATS_IO_READ,
+					rd, NFSD_A_SERVER_STATS_PAD) ||
+			    nla_put_u64_64bit(skb, NFSD_A_SERVER_STATS_IO_WRITE,
+					wr, NFSD_A_SERVER_STATS_PAD))
+				goto err_cancel;
+		}
+
+		/* Network stats */
+		if (nla_put_u32(skb, NFSD_A_SERVER_STATS_NETCNT,
+				statp->netcnt) ||
+		    nla_put_u32(skb, NFSD_A_SERVER_STATS_NETUDPCNT,
+				statp->netudpcnt) ||
+		    nla_put_u32(skb, NFSD_A_SERVER_STATS_NETTCPCNT,
+				statp->nettcpcnt) ||
+		    nla_put_u32(skb, NFSD_A_SERVER_STATS_NETTCPCONN,
+				statp->nettcpconn))
+			goto err_cancel;
+
+		/* RPC stats */
+		if (nla_put_u32(skb, NFSD_A_SERVER_STATS_RPCCNT,
+				statp->rpccnt) ||
+		    nla_put_u32(skb, NFSD_A_SERVER_STATS_RPCBADFMT,
+				statp->rpcbadfmt) ||
+		    nla_put_u32(skb, NFSD_A_SERVER_STATS_RPCBADAUTH,
+				statp->rpcbadauth) ||
+		    nla_put_u32(skb, NFSD_A_SERVER_STATS_RPCBADCLNT,
+				statp->rpcbadclnt))
+			goto err_cancel;
+
+		/* Per-version procedure counts */
+		if (statp->vs_count) {
+			static const int proc_attrs[] = {
+				[2] = NFSD_A_SERVER_STATS_PROC2_OPS,
+				[3] = NFSD_A_SERVER_STATS_PROC3_OPS,
+				[4] = NFSD_A_SERVER_STATS_PROC4_OPS,
+			};
+			unsigned int i;
+
+			for (i = 0; i < prog->pg_nvers &&
+			     i < ARRAY_SIZE(proc_attrs); i++) {
+				if (!prog->pg_vers[i] ||
+				    !statp->vs_count[i])
+					continue;
+				if (!proc_attrs[i])
+					continue;
+				if (nfsd_nl_fill_proc_ops(skb,
+						proc_attrs[i],
+						statp->vs_count[i],
+						prog->pg_vers[i]->vs_nproc))
+					goto err_cancel;
+			}
+		}
+
+		genlmsg_end(skb, hdr);
+		cb->args[0] = 1;
+	}
+
+#ifdef CONFIG_NFSD_V4
+	/* NFSv4 individual operation counts */
+	{
+		int i = (start > 0) ? start - 1 : 0;
+
+		for (; i <= LAST_NFS4_OP; i++) {
+			struct percpu_counter *ctr;
+			struct nlattr *nest;
+			u64 cnt;
+
+			ctr = &nn->counter[NFSD_STATS_NFS4_OP(i)];
+			cnt = percpu_counter_sum_positive(ctr);
+
+			hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
+					  cb->nlh->nlmsg_seq,
+					  &nfsd_nl_family, NLM_F_MULTI,
+					  NFSD_CMD_SERVER_STATS_GET);
+			if (!hdr) {
+				cb->args[0] = i + 1;
+				goto out;
+			}
+
+			nest = nla_nest_start(skb,
+					NFSD_A_SERVER_STATS_PROC4OPS_OPS);
+			if (!nest) {
+				genlmsg_cancel(skb, hdr);
+				cb->args[0] = i + 1;
+				goto out;
+			}
+			if (nla_put_u32(skb, NFSD_A_SERVER_PROC_ENTRY_OP,
+					i) ||
+			    nla_put_u64_64bit(skb,
+					NFSD_A_SERVER_PROC_ENTRY_COUNT,
+					cnt,
+					NFSD_A_SERVER_PROC_ENTRY_PAD)) {
+				nla_nest_cancel(skb, nest);
+				genlmsg_cancel(skb, hdr);
+				cb->args[0] = i + 1;
+				goto out;
+			}
+			nla_nest_end(skb, nest);
+			genlmsg_end(skb, hdr);
+		}
+	}
+#endif
+
+	cb->args[0] = -1;
+out:
+	return skb->len;
+
+err_cancel:
+	genlmsg_cancel(skb, hdr);
+	return -EMSGSIZE;
+}
+
 int nfsd_cache_notify(struct cache_detail *cd, struct cache_head *h, u32 cache_type)
 {
 	struct genlmsghdr *hdr;
diff --git a/include/uapi/linux/nfsd_netlink.h b/include/uapi/linux/nfsd_netlink.h
index f5b75d5caba9..3d076d173b1d 100644
--- a/include/uapi/linux/nfsd_netlink.h
+++ b/include/uapi/linux/nfsd_netlink.h
@@ -225,6 +225,40 @@ enum {
 	NFSD_A_UNLOCK_EXPORT_MAX = (__NFSD_A_UNLOCK_EXPORT_MAX - 1)
 };
 
+enum {
+	NFSD_A_SERVER_PROC_ENTRY_OP = 1,
+	NFSD_A_SERVER_PROC_ENTRY_COUNT,
+	NFSD_A_SERVER_PROC_ENTRY_PAD,
+
+	__NFSD_A_SERVER_PROC_ENTRY_MAX,
+	NFSD_A_SERVER_PROC_ENTRY_MAX = (__NFSD_A_SERVER_PROC_ENTRY_MAX - 1)
+};
+
+enum {
+	NFSD_A_SERVER_STATS_RC_HITS = 1,
+	NFSD_A_SERVER_STATS_RC_MISSES,
+	NFSD_A_SERVER_STATS_RC_NOCACHE,
+	NFSD_A_SERVER_STATS_PAD,
+	NFSD_A_SERVER_STATS_FH_STALE,
+	NFSD_A_SERVER_STATS_IO_READ,
+	NFSD_A_SERVER_STATS_IO_WRITE,
+	NFSD_A_SERVER_STATS_NETCNT,
+	NFSD_A_SERVER_STATS_NETUDPCNT,
+	NFSD_A_SERVER_STATS_NETTCPCNT,
+	NFSD_A_SERVER_STATS_NETTCPCONN,
+	NFSD_A_SERVER_STATS_RPCCNT,
+	NFSD_A_SERVER_STATS_RPCBADFMT,
+	NFSD_A_SERVER_STATS_RPCBADAUTH,
+	NFSD_A_SERVER_STATS_RPCBADCLNT,
+	NFSD_A_SERVER_STATS_PROC2_OPS,
+	NFSD_A_SERVER_STATS_PROC3_OPS,
+	NFSD_A_SERVER_STATS_PROC4_OPS,
+	NFSD_A_SERVER_STATS_PROC4OPS_OPS,
+
+	__NFSD_A_SERVER_STATS_MAX,
+	NFSD_A_SERVER_STATS_MAX = (__NFSD_A_SERVER_STATS_MAX - 1)
+};
+
 enum {
 	NFSD_CMD_RPC_STATUS_GET = 1,
 	NFSD_CMD_THREADS_SET,
@@ -244,6 +278,7 @@ enum {
 	NFSD_CMD_UNLOCK_IP,
 	NFSD_CMD_UNLOCK_FILESYSTEM,
 	NFSD_CMD_UNLOCK_EXPORT,
+	NFSD_CMD_SERVER_STATS_GET,
 
 	__NFSD_CMD_MAX,
 	NFSD_CMD_MAX = (__NFSD_CMD_MAX - 1)

-- 
2.54.0

[PATCH v4 4/4] sunrpc: remove unused svc_version vs_count field

[Jeff Layton]

Now that svc_seq_show() and the nfsd netlink stats handler both use
the per-netns svc_stat vs_count arrays, the global per-version
vs_count percpu counters are no longer read by anything. Remove the
vs_count field from struct svc_version and all the associated
DEFINE_PER_CPU_ALIGNED arrays and initializers across nfsd, lockd,
and the NFS client callback service.

Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/lockd/svc4proc.c        | 4 ----
 fs/lockd/svcproc.c         | 7 -------
 fs/nfs/callback_xdr.c      | 6 ------
 fs/nfsd/localio.c          | 3 ---
 fs/nfsd/nfs2acl.c          | 3 ---
 fs/nfsd/nfs3acl.c          | 3 ---
 fs/nfsd/nfs3proc.c         | 3 ---
 fs/nfsd/nfs4proc.c         | 3 ---
 fs/nfsd/nfsproc.c          | 3 ---
 include/linux/sunrpc/svc.h | 1 -
 net/sunrpc/svc.c           | 3 ---
 11 files changed, 39 deletions(-)

diff --git a/fs/lockd/svc4proc.c b/fs/lockd/svc4proc.c
index 080dffce9d8e..c096c0c0cf60 100644
--- a/fs/lockd/svc4proc.c
+++ b/fs/lockd/svc4proc.c
@@ -1420,14 +1420,10 @@ union nlm4svc_xdrstore {
 	struct nlm4_shareres_wrapper	shareres;
 };
 
-static DEFINE_PER_CPU_ALIGNED(unsigned long,
-			      nlm4svc_call_counters[ARRAY_SIZE(nlm4svc_procedures)]);
-
 const struct svc_version nlmsvc_version4 = {
 	.vs_vers	= 4,
 	.vs_nproc	= ARRAY_SIZE(nlm4svc_procedures),
 	.vs_proc	= nlm4svc_procedures,
-	.vs_count	= nlm4svc_call_counters,
 	.vs_dispatch	= nlmsvc_dispatch,
 	.vs_xdrsize	= sizeof(union nlm4svc_xdrstore),
 };
diff --git a/fs/lockd/svcproc.c b/fs/lockd/svcproc.c
index dce6f6e3fd40..07f65a03f300 100644
--- a/fs/lockd/svcproc.c
+++ b/fs/lockd/svcproc.c
@@ -1433,25 +1433,18 @@ union nlmsvc_xdrstore {
  * NLMv1 defines only procedures 1 - 15. Linux lockd also implements
  * procedures 0 (NULL) and 16 (SM_NOTIFY).
  */
-static DEFINE_PER_CPU_ALIGNED(unsigned long, nlm1svc_call_counters[17]);
-
 const struct svc_version nlmsvc_version1 = {
 	.vs_vers	= 1,
 	.vs_nproc	= 17,
 	.vs_proc	= nlmsvc_procedures,
-	.vs_count	= nlm1svc_call_counters,
 	.vs_dispatch	= nlmsvc_dispatch,
 	.vs_xdrsize	= sizeof(union nlmsvc_xdrstore),
 };
 
-static DEFINE_PER_CPU_ALIGNED(unsigned long,
-			      nlm3svc_call_counters[ARRAY_SIZE(nlmsvc_procedures)]);
-
 const struct svc_version nlmsvc_version3 = {
 	.vs_vers	= 3,
 	.vs_nproc	= ARRAY_SIZE(nlmsvc_procedures),
 	.vs_proc	= nlmsvc_procedures,
-	.vs_count	= nlm3svc_call_counters,
 	.vs_dispatch	= nlmsvc_dispatch,
 	.vs_xdrsize	= sizeof(union nlmsvc_xdrstore),
 };
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 4382baddc9ee..eec6040556c9 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -1090,26 +1090,20 @@ static const struct svc_procedure nfs4_callback_procedures1[] = {
 	}
 };
 
-static DEFINE_PER_CPU_ALIGNED(unsigned long,
-			      nfs4_callback_count1[ARRAY_SIZE(nfs4_callback_procedures1)]);
 const struct svc_version nfs4_callback_version1 = {
 	.vs_vers = 1,
 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
 	.vs_proc = nfs4_callback_procedures1,
-	.vs_count = nfs4_callback_count1,
 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
 	.vs_dispatch = nfs_callback_dispatch,
 	.vs_hidden = true,
 	.vs_need_cong_ctrl = true,
 };
 
-static DEFINE_PER_CPU_ALIGNED(unsigned long,
-			      nfs4_callback_count4[ARRAY_SIZE(nfs4_callback_procedures1)]);
 const struct svc_version nfs4_callback_version4 = {
 	.vs_vers = 4,
 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
 	.vs_proc = nfs4_callback_procedures1,
-	.vs_count = nfs4_callback_count4,
 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
 	.vs_dispatch = nfs_callback_dispatch,
 	.vs_hidden = true,
diff --git a/fs/nfsd/localio.c b/fs/nfsd/localio.c
index c3eb0557b3e1..c458c01e9478 100644
--- a/fs/nfsd/localio.c
+++ b/fs/nfsd/localio.c
@@ -210,14 +210,11 @@ static const struct svc_procedure localio_procedures1[] = {
 };
 
 #define LOCALIO_NR_PROCEDURES ARRAY_SIZE(localio_procedures1)
-static DEFINE_PER_CPU_ALIGNED(unsigned long,
-			      localio_count[LOCALIO_NR_PROCEDURES]);
 const struct svc_version localio_version1 = {
 	.vs_vers	= 1,
 	.vs_nproc	= LOCALIO_NR_PROCEDURES,
 	.vs_proc	= localio_procedures1,
 	.vs_dispatch	= nfsd_dispatch,
-	.vs_count	= localio_count,
 	.vs_xdrsize	= XDR_QUADLEN(UUID_SIZE),
 	.vs_hidden	= true,
 };
diff --git a/fs/nfsd/nfs2acl.c b/fs/nfsd/nfs2acl.c
index 827f90194c43..0fd6d9def3b4 100644
--- a/fs/nfsd/nfs2acl.c
+++ b/fs/nfsd/nfs2acl.c
@@ -389,13 +389,10 @@ static const struct svc_procedure nfsd_acl_procedures2[5] = {
 	},
 };
 
-static DEFINE_PER_CPU_ALIGNED(unsigned long,
-			      nfsd_acl_count2[ARRAY_SIZE(nfsd_acl_procedures2)]);
 const struct svc_version nfsd_acl_version2 = {
 	.vs_vers	= 2,
 	.vs_nproc	= ARRAY_SIZE(nfsd_acl_procedures2),
 	.vs_proc	= nfsd_acl_procedures2,
-	.vs_count	= nfsd_acl_count2,
 	.vs_dispatch	= nfsd_dispatch,
 	.vs_xdrsize	= NFS3_SVC_XDRSIZE,
 };
diff --git a/fs/nfsd/nfs3acl.c b/fs/nfsd/nfs3acl.c
index a87f9d7f32be..6b6b289db636 100644
--- a/fs/nfsd/nfs3acl.c
+++ b/fs/nfsd/nfs3acl.c
@@ -278,13 +278,10 @@ static const struct svc_procedure nfsd_acl_procedures3[3] = {
 	},
 };
 
-static DEFINE_PER_CPU_ALIGNED(unsigned long,
-			      nfsd_acl_count3[ARRAY_SIZE(nfsd_acl_procedures3)]);
 const struct svc_version nfsd_acl_version3 = {
 	.vs_vers	= 3,
 	.vs_nproc	= ARRAY_SIZE(nfsd_acl_procedures3),
 	.vs_proc	= nfsd_acl_procedures3,
-	.vs_count	= nfsd_acl_count3,
 	.vs_dispatch	= nfsd_dispatch,
 	.vs_xdrsize	= NFS3_SVC_XDRSIZE,
 };
diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index aeda7a802bdf..2d5ab2178702 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -1068,13 +1068,10 @@ static const struct svc_procedure nfsd_procedures3[22] = {
 	},
 };
 
-static DEFINE_PER_CPU_ALIGNED(unsigned long,
-			      nfsd_count3[ARRAY_SIZE(nfsd_procedures3)]);
 const struct svc_version nfsd_version3 = {
 	.vs_vers	= 3,
 	.vs_nproc	= ARRAY_SIZE(nfsd_procedures3),
 	.vs_proc	= nfsd_procedures3,
 	.vs_dispatch	= nfsd_dispatch,
-	.vs_count	= nfsd_count3,
 	.vs_xdrsize	= NFS3_SVC_XDRSIZE,
 };
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 3e4de45aa360..fbfa69cb9dcc 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -4151,13 +4151,10 @@ static const struct svc_procedure nfsd_procedures4[2] = {
 	},
 };
 
-static DEFINE_PER_CPU_ALIGNED(unsigned long,
-			      nfsd_count4[ARRAY_SIZE(nfsd_procedures4)]);
 const struct svc_version nfsd_version4 = {
 	.vs_vers		= 4,
 	.vs_nproc		= ARRAY_SIZE(nfsd_procedures4),
 	.vs_proc		= nfsd_procedures4,
-	.vs_count		= nfsd_count4,
 	.vs_dispatch		= nfsd_dispatch,
 	.vs_xdrsize		= NFS4_SVC_XDRSIZE,
 	.vs_rpcb_optnl		= true,
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index a73d5c259cd9..b8421cde795a 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -845,13 +845,10 @@ static const struct svc_procedure nfsd_procedures2[18] = {
 	},
 };
 
-static DEFINE_PER_CPU_ALIGNED(unsigned long,
-			      nfsd_count2[ARRAY_SIZE(nfsd_procedures2)]);
 const struct svc_version nfsd_version2 = {
 	.vs_vers	= 2,
 	.vs_nproc	= ARRAY_SIZE(nfsd_procedures2),
 	.vs_proc	= nfsd_procedures2,
-	.vs_count	= nfsd_count2,
 	.vs_dispatch	= nfsd_dispatch,
 	.vs_xdrsize	= NFS2_SVC_XDRSIZE,
 };
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 3a0152d926fb..34490c0ba88c 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -408,7 +408,6 @@ struct svc_version {
 	u32			vs_vers;	/* version number */
 	u32			vs_nproc;	/* number of procedures */
 	const struct svc_procedure *vs_proc;	/* per-procedure info */
-	unsigned long __percpu	*vs_count;	/* call counts */
 	u32			vs_xdrsize;	/* xdrsize needed for this version */
 
 	/* Don't register with rpcbind */
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index f748004835f7..dce268d8ec8e 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1435,9 +1435,6 @@ svc_generic_init_request(struct svc_rqst *rqstp,
 	memset(rqstp->rq_argp, 0, procp->pc_argzero);
 	memset(rqstp->rq_resp, 0, procp->pc_ressize);
 
-	/* Bump per-procedure stats counter */
-	this_cpu_inc(versp->vs_count[rqstp->rq_proc]);
-
 	/* Bump per-net per-procedure stats counter */
 	if (rqstp->rq_server->sv_stats &&
 	    rqstp->rq_server->sv_stats->program == progp &&

-- 
2.54.0

Re: [PATCH v4 1/4] sunrpc: add per-netns per-procedure call counts to svc_stat

[Chuck Lever]

Hey Jeff -

On Tue, Jun 16, 2026, at 8:45 AM, Jeff Layton wrote:
> The existing per-procedure call counts live in global
> svc_version->vs_count[] arrays which are not network-namespace-aware.
> Add per-netns equivalents in struct svc_stat so the upcoming netlink
> stats interface can return namespace-scoped statistics.
>
> Add a vs_count pointer array to struct svc_stat, along with
> svc_stat_alloc_counts() and svc_stat_free_counts() helpers to manage
> per-version percpu call count arrays.

This patch appears to break the build for an NFSv3-only server
configured with CONFIG_PROC_FS=n.

svc_stat_alloc_counts() and svc_stat_free_counts() are defined in
net/sunrpc/stats.c, which the Makefile builds only under PROC_FS:

       sunrpc-$(CONFIG_PROC_FS) += stats.o

nfsd_net_init()/nfsd_net_exit() call both helpers unconditionally,
and the declarations in <linux/sunrpc/stats.h> sit outside the
#ifdef CONFIG_PROC_FS block with no !PROC_FS stubs. CONFIG_NFSD does
not depend on PROC_FS -- only NFSD_V4 does -- so NFSD=y with
NFSD_V2/V3 and PROC_FS=n is a valid Kconfig combination. The result
is an undefined reference to svc_stat_alloc_counts at vmlinux link
(NFSD=y), or a modpost failure for NFSD=m since both symbols are
EXPORT_SYMBOL_GPL.

net/sunrpc/svc.c is always built, and might be a more natural home
for the new functions.

-- 
Chuck Lever

Re: [PATCH v4 3/4] nfsd: implement server-stats-get netlink handler

[Chuck Lever]

Hey Jeff -

On Tue, Jun 16, 2026, at 8:45 AM, Jeff Layton wrote:
> Implement nfsd_nl_server_stats_get_dumpit() which exposes the
> NFS server statistics currently available via /proc/net/rpc/nfsd
> through the nfsd generic netlink family.
>
> The handler uses a dump operation to stream statistics across
> multiple netlink messages:
>
>   - First message: all scalar stats (reply cache, filehandle,
>     IO, network, RPC) plus per-version procedure counts
>     (proc2/3/4-ops) using per-netns vs_count arrays.
>
>   - Subsequent messages: NFSv4 per-operation counts
>     (proc4ops-ops), one entry per message, using cb->args[0]
>     to track the current operation index across dump calls.
>
> This allows nfsstat to retrieve server statistics via netlink
> with a procfs fallback for older kernels.
>
> Assisted-by: Claude:claude-opus-4-6
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
>  Documentation/netlink/specs/nfsd.yaml | 105 +++++++++++++++++
>  fs/nfsd/netlink.c                     |   5 +
>  fs/nfsd/netlink.h                     |   2 +
>  fs/nfsd/nfsctl.c                      | 206 ++++++++++++++++++++++++++++++++++
>  include/uapi/linux/nfsd_netlink.h     |  35 ++++++
>  5 files changed, 353 insertions(+)

The procfs output in nfsd_show() emits one more counter that this dump
handler drops: wdeleg_getattr (NFSD_STATS_WDELEG_GETATTR), printed at
the end of the CONFIG_NFSD_V4 block in fs/nfsd/stats.c, right after
proc4ops. The netlink dump stops after proc4ops-ops and sets
cb->args[0] = -1, so the write-delegation GETATTR-conflict counter never
goes out on the wire.

There's no schema slot for it either: the server-stats attribute-set
ends at proc4ops-ops, so a consumer that prefers netlink and only falls
back to procfs on an old kernel loses this counter on every kernel new
enough to support server-stats-get.

I Suggest:

- add a wdeleg-getattr (u64) attribute to the server-stats
  attribute-set in nfsd.yaml and list it under the dump reply
  attributes;

- add NFSD_A_SERVER_STATS_WDELEG_GETATTR to the uapi enum, after
  PROC4OPS_OPS and before __NFSD_A_SERVER_STATS_MAX so existing
  values don't shift;

- emit it as a single scalar in the start == 0 message, wrapped in
  CONFIG_NFSD_V4 to match the procfs side.


-- 
Chuck Lever