[PATCH v5 0/6] nfsd/sunrpc: convert nfsstat server-side interfaces to use netlink

[PATCH v5 0/6] nfsd/sunrpc: convert nfsstat server-side interfaces to use netlink

[Jeff Layton]

The main difference in this version is the addition of server callback
operation counts. I'll be sending another nfs-utils patch to add support
for displaying those in nfsstat.

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. The nfs-utils patch for that part is already merged.

Additionally, this version adds tracking of callback operation counts.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
Changes in v5:
- Add NFSv4 callback call counts to nfsstat upcall
- Link to v4: https://lore.kernel.org/r/20260616-exportd-netlink-v4-0-03505aee3883@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 (6):
      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
      nfsd: count NFSv4 callback operations per netns
      nfsd: export NFSv4 callback op stats via netlink

 Documentation/netlink/specs/nfsd.yaml | 111 +++++++++++++++
 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/netns.h                       |  12 +-
 fs/nfsd/nfs2acl.c                     |   3 -
 fs/nfsd/nfs3acl.c                     |   3 -
 fs/nfsd/nfs3proc.c                    |   3 -
 fs/nfsd/nfs4callback.c                |   7 +-
 fs/nfsd/nfs4proc.c                    |   3 -
 fs/nfsd/nfs4state.c                   |   2 -
 fs/nfsd/nfsctl.c                      | 250 +++++++++++++++++++++++++++++++++-
 fs/nfsd/nfsproc.c                     |   3 -
 fs/nfsd/stats.c                       |   2 +-
 fs/nfsd/stats.h                       |   5 +-
 include/linux/sunrpc/stats.h          |   6 +
 include/linux/sunrpc/svc.h            |   1 -
 include/uapi/linux/nfsd_netlink.h     |  36 +++++
 net/sunrpc/stats.c                    |   2 +-
 net/sunrpc/svc.c                      |  63 ++++++++-
 23 files changed, 492 insertions(+), 47 deletions(-)
---
base-commit: 6f90c7618528b5ca5887f8c6057f26dcc7a27a99
change-id: 20260316-exportd-netlink-1c9fb52536e3

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

[PATCH v5 1/6] 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/svc.c             | 62 ++++++++++++++++++++++++++++++++++++++++++++
 3 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/svc.c b/net/sunrpc/svc.c
index dd80a2eaaa74..0cee079df1cb 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:
@@ -1449,6 +1457,60 @@ svc_generic_init_request(struct svc_rqst *rqstp,
 }
 EXPORT_SYMBOL_GPL(svc_generic_init_request);
 
+/**
+ * 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);
+
 /*
  * Common routine for processing the RPC request.
  */

-- 
2.54.0

[PATCH v5 2/6] 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 7093e18ac26c..d08711bee18e 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 v5 3/6] 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                      | 205 ++++++++++++++++++++++++++++++++++
 include/uapi/linux/nfsd_netlink.h     |  35 ++++++
 5 files changed, 352 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..dde026473806 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -2329,6 +2329,211 @@ 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;
+				return skb->len;
+			}
+
+			nest = nla_nest_start(skb,
+					NFSD_A_SERVER_STATS_PROC4OPS_OPS);
+			if (!nest) {
+				genlmsg_cancel(skb, hdr);
+				cb->args[0] = i + 1;
+				return skb->len;
+			}
+			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;
+				return skb->len;
+			}
+			nla_nest_end(skb, nest);
+			genlmsg_end(skb, hdr);
+		}
+	}
+#endif
+
+	cb->args[0] = -1;
+	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 v5 4/6] 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 617a70d13292..a547ffc9b3d1 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -1108,13 +1108,10 @@ 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 c413ed0810b9..005a9ce7ceb8 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -4177,13 +4177,10 @@ 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 0cee079df1cb..8be33ffb32c8 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

[PATCH v5 5/6] nfsd: count NFSv4 callback operations per netns

[Jeff Layton]

The NFS server tracks per-operation call counts for the forward channel
(proc4ops) but keeps no statistics for the NFSv4 backchannel (callback)
operations it sends to clients.

Add a per-netns array of percpu counters for callback operations, indexed
by RFC 8881 callback opcode (OP_CB_GETATTR..OP_CB_OFFLOAD), and bump the
relevant counter in nfsd4_run_cb(), which is hit exactly once per callback
that is actually queued.

CB_GETATTR is sent when a GETATTR conflicts with an outstanding write
delegation, which is roughly what the dedicated wdeleg_getattr counter
tracked. The two are not identical: the old counter incremented on every
such conflict, whereas the CB_GETATTR counter only counts callbacks that
are actually queued, so concurrent conflicts that coalesce onto an
already in-flight CB_GETATTR are now counted once rather than once per
conflict. Report the procfs "wdeleg_getattr" line from the CB_GETATTR
counter and drop the now-redundant NFSD_STATS_WDELEG_GETATTR counter, its
helper, and its increment site.

Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/nfsd/netns.h        | 12 +++++++++++-
 fs/nfsd/nfs4callback.c |  7 ++++++-
 fs/nfsd/nfs4state.c    |  2 --
 fs/nfsd/nfsctl.c       | 14 ++++++++++++++
 fs/nfsd/stats.c        |  2 +-
 fs/nfsd/stats.h        |  5 +++--
 6 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index 03724bef10a7..37daba0d4747 100644
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h
@@ -53,11 +53,16 @@ enum {
 	NFSD_STATS_FIRST_NFS4_OP,	/* count of individual nfsv4 operations */
 	NFSD_STATS_LAST_NFS4_OP = NFSD_STATS_FIRST_NFS4_OP + LAST_NFS4_OP,
 #define NFSD_STATS_NFS4_OP(op)	(NFSD_STATS_FIRST_NFS4_OP + (op))
-	NFSD_STATS_WDELEG_GETATTR,	/* count of getattr conflict with wdeleg */
 #endif
 	NFSD_STATS_COUNTERS_NUM
 };
 
+/*
+ * Per-netns NFSv4 callback (backchannel) per-operation counters, indexed
+ * directly by RFC 8881 callback opcode (OP_CB_GETATTR..OP_CB_OFFLOAD).
+ */
+#define NFSD_STATS_CB_OPS_NUM	(OP_CB_OFFLOAD + 1)
+
 /*
  * Represents a nfsd "container". With respect to nfsv4 state tracking, the
  * fields of interest are the *_id_hashtbls and the *_name_tree. These track
@@ -198,6 +203,11 @@ struct nfsd_net {
 	/* Per-netns stats counters */
 	struct percpu_counter    counter[NFSD_STATS_COUNTERS_NUM];
 
+#ifdef CONFIG_NFSD_V4
+	/* Per-netns NFSv4 callback (backchannel) per-operation counters */
+	struct percpu_counter    cb_counter[NFSD_STATS_CB_OPS_NUM];
+#endif
+
 	/* sunrpc svc stats */
 	struct svc_stat          nfsd_svcstats;
 
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 71dcb448fa0a..9cbcccc26b35 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -1925,8 +1925,13 @@ bool nfsd4_run_cb(struct nfsd4_callback *cb)
 
 	nfsd41_cb_inflight_begin(clp);
 	queued = nfsd4_queue_cb(cb);
-	if (!queued)
+	if (queued) {
+		if (cb->cb_ops)
+			nfsd_stats_cb_op_inc(net_generic(clp->net, nfsd_net_id),
+					     cb->cb_ops->opcode);
+	} else {
 		nfsd41_cb_inflight_end(clp);
+	}
 	return queued;
 }
 
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index b830aed7ae39..8f8da1312231 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -9904,7 +9904,6 @@ __be32
 nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct dentry *dentry,
 			     struct nfs4_delegation **pdp)
 {
-	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 	struct nfsd_thread_local_info *ntli = rqstp->rq_private;
 	struct file_lock_context *ctx;
 	struct nfs4_delegation *dp = NULL;
@@ -9944,7 +9943,6 @@ nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct dentry *dentry,
 		return 0;
 	}
 
-	nfsd_stats_wdeleg_getattr_inc(nn);
 	refcount_inc(&dp->dl_stid.sc_count);
 	ncf = &dp->dl_cb_fattr;
 	nfs4_cb_getattr(&dp->dl_cb_fattr);
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index dde026473806..9bedbe7096c3 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -2717,6 +2717,13 @@ static __net_init int nfsd_net_init(struct net *net)
 	if (retval)
 		goto out_repcache_error;
 
+#ifdef CONFIG_NFSD_V4
+	retval = percpu_counter_init_many(nn->cb_counter, 0, GFP_KERNEL,
+					  NFSD_STATS_CB_OPS_NUM);
+	if (retval)
+		goto out_cb_counter_error;
+#endif
+
 	memset(&nn->nfsd_svcstats, 0, sizeof(nn->nfsd_svcstats));
 	nn->nfsd_svcstats.program = &nfsd_programs[0];
 	retval = svc_stat_alloc_counts(&nn->nfsd_svcstats);
@@ -2745,6 +2752,10 @@ static __net_init int nfsd_net_init(struct net *net)
 out_svcstats_error:
 	svc_stat_free_counts(&nn->nfsd_svcstats);
 out_proc_error:
+#ifdef CONFIG_NFSD_V4
+	percpu_counter_destroy_many(nn->cb_counter, NFSD_STATS_CB_OPS_NUM);
+out_cb_counter_error:
+#endif
 	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
 out_repcache_error:
 	nfsd_idmap_shutdown(net);
@@ -2785,6 +2796,9 @@ static __net_exit void nfsd_net_exit(struct net *net)
 	nfsd_net_cb_shutdown(nn);
 	nfsd_proc_stat_shutdown(net);
 	svc_stat_free_counts(&nn->nfsd_svcstats);
+#ifdef CONFIG_NFSD_V4
+	percpu_counter_destroy_many(nn->cb_counter, NFSD_STATS_CB_OPS_NUM);
+#endif
 	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
 	nfsd_idmap_shutdown(net);
 	nfsd_export_shutdown(net);
diff --git a/fs/nfsd/stats.c b/fs/nfsd/stats.c
index f7eaf95e20fc..35d9a5571946 100644
--- a/fs/nfsd/stats.c
+++ b/fs/nfsd/stats.c
@@ -63,7 +63,7 @@ static int nfsd_show(struct seq_file *seq, void *v)
 			   percpu_counter_sum_positive(&nn->counter[NFSD_STATS_NFS4_OP(i)]));
 	}
 	seq_printf(seq, "\nwdeleg_getattr %lld",
-		percpu_counter_sum_positive(&nn->counter[NFSD_STATS_WDELEG_GETATTR]));
+		percpu_counter_sum_positive(&nn->cb_counter[OP_CB_GETATTR]));
 
 	seq_putc(seq, '\n');
 #endif
diff --git a/fs/nfsd/stats.h b/fs/nfsd/stats.h
index e4efb0e4e56d..f90cd565f7cb 100644
--- a/fs/nfsd/stats.h
+++ b/fs/nfsd/stats.h
@@ -68,9 +68,10 @@ static inline void nfsd_stats_drc_mem_usage_sub(struct nfsd_net *nn, s64 amount)
 }
 
 #ifdef CONFIG_NFSD_V4
-static inline void nfsd_stats_wdeleg_getattr_inc(struct nfsd_net *nn)
+static inline void nfsd_stats_cb_op_inc(struct nfsd_net *nn, u32 opcode)
 {
-	percpu_counter_inc(&nn->counter[NFSD_STATS_WDELEG_GETATTR]);
+	if (opcode >= OP_CB_GETATTR && opcode <= OP_CB_OFFLOAD)
+		percpu_counter_inc(&nn->cb_counter[opcode]);
 }
 #endif
 #endif /* _NFSD_STATS_H */

-- 
2.54.0

[PATCH v5 6/6] nfsd: export NFSv4 callback op stats via netlink

[Jeff Layton]

Add a proc4cb-ops nested attribute to the server-stats netlink dump,
reusing the existing server-proc-entry (op/count) layout. The first dump
message emits one entry per callback opcode (OP_CB_GETATTR..OP_CB_OFFLOAD)
from the per-netns callback counters; the set is small and fits alongside
the scalar stats, so no extra paging is needed.

This lets nfsstat report NFSv4 backchannel operation counts over netlink,
including CB_GETATTR which corresponds to the procfs wdeleg_getattr line.

Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 Documentation/netlink/specs/nfsd.yaml |  6 ++++++
 fs/nfsd/nfsctl.c                      | 23 +++++++++++++++++++++++
 include/uapi/linux/nfsd_netlink.h     |  1 +
 3 files changed, 30 insertions(+)

diff --git a/Documentation/netlink/specs/nfsd.yaml b/Documentation/netlink/specs/nfsd.yaml
index 2a89d355ee7b..642268819c6f 100644
--- a/Documentation/netlink/specs/nfsd.yaml
+++ b/Documentation/netlink/specs/nfsd.yaml
@@ -410,6 +410,11 @@ attribute-sets:
         type: nest
         nested-attributes: server-proc-entry
         multi-attr: true
+      -
+        name: proc4cb-ops
+        type: nest
+        nested-attributes: server-proc-entry
+        multi-attr: true
 
 operations:
   list:
@@ -621,6 +626,7 @@ operations:
             - proc3-ops
             - proc4-ops
             - proc4ops-ops
+            - proc4cb-ops
 
 mcast-groups:
   list:
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 9bedbe7096c3..674fab6a86a5 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -2476,6 +2476,29 @@ int nfsd_nl_server_stats_get_dumpit(struct sk_buff *skb,
 			}
 		}
 
+#ifdef CONFIG_NFSD_V4
+		/* NFSv4 callback (backchannel) per-operation counts */
+		for (int op = OP_CB_GETATTR; op <= OP_CB_OFFLOAD; op++) {
+			struct nlattr *nest;
+			u64 cnt;
+
+			cnt = percpu_counter_sum_positive(
+				&nn->cb_counter[op]);
+
+			nest = nla_nest_start(skb,
+					NFSD_A_SERVER_STATS_PROC4CB_OPS);
+			if (!nest)
+				goto err_cancel;
+			if (nla_put_u32(skb, NFSD_A_SERVER_PROC_ENTRY_OP, op) ||
+			    nla_put_u64_64bit(skb, NFSD_A_SERVER_PROC_ENTRY_COUNT,
+					      cnt, NFSD_A_SERVER_PROC_ENTRY_PAD)) {
+				nla_nest_cancel(skb, nest);
+				goto err_cancel;
+			}
+			nla_nest_end(skb, nest);
+		}
+#endif
+
 		genlmsg_end(skb, hdr);
 		cb->args[0] = 1;
 	}
diff --git a/include/uapi/linux/nfsd_netlink.h b/include/uapi/linux/nfsd_netlink.h
index 3d076d173b1d..87da1d0bb21e 100644
--- a/include/uapi/linux/nfsd_netlink.h
+++ b/include/uapi/linux/nfsd_netlink.h
@@ -254,6 +254,7 @@ enum {
 	NFSD_A_SERVER_STATS_PROC3_OPS,
 	NFSD_A_SERVER_STATS_PROC4_OPS,
 	NFSD_A_SERVER_STATS_PROC4OPS_OPS,
+	NFSD_A_SERVER_STATS_PROC4CB_OPS,
 
 	__NFSD_A_SERVER_STATS_MAX,
 	NFSD_A_SERVER_STATS_MAX = (__NFSD_A_SERVER_STATS_MAX - 1)

-- 
2.54.0