diff --git a/fs/nfsd/Makefile b/fs/nfsd/Makefile
index b8736a82e57c..18cbd3fa7691 100644
--- a/fs/nfsd/Makefile
+++ b/fs/nfsd/Makefile
@@ -23,3 +23,4 @@ nfsd-$(CONFIG_NFSD_PNFS) += nfs4layouts.o
 nfsd-$(CONFIG_NFSD_BLOCKLAYOUT) += blocklayout.o blocklayoutxdr.o
 nfsd-$(CONFIG_NFSD_SCSILAYOUT) += blocklayout.o blocklayoutxdr.o
 nfsd-$(CONFIG_NFSD_FLEXFILELAYOUT) += flexfilelayout.o flexfilelayoutxdr.o
+nfsd-$(CONFIG_NFS_LOCALIO) += localio.o
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 89ff380ec31e..348c1b97092e 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -52,7 +52,7 @@
 #define NFSD_FILE_CACHE_UP		     (0)
 
 /* We only care about NFSD_MAY_READ/WRITE for this cache */
-#define NFSD_FILE_MAY_MASK	(NFSD_MAY_READ|NFSD_MAY_WRITE)
+#define NFSD_FILE_MAY_MASK	(NFSD_MAY_READ|NFSD_MAY_WRITE|NFSD_MAY_LOCALIO)
 
 static DEFINE_PER_CPU(unsigned long, nfsd_file_cache_hits);
 static DEFINE_PER_CPU(unsigned long, nfsd_file_acquisitions);
diff --git a/fs/nfsd/localio.c b/fs/nfsd/localio.c
new file mode 100644
index 000000000000..75df709c6903
--- /dev/null
+++ b/fs/nfsd/localio.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * NFS server support for local clients to bypass network stack
+ *
+ * Copyright (C) 2014 Weston Andros Adamson <dros@primarydata.com>
+ * Copyright (C) 2019 Trond Myklebust <trond.myklebust@hammerspace.com>
+ * Copyright (C) 2024 Mike Snitzer <snitzer@hammerspace.com>
+ * Copyright (C) 2024 NeilBrown <neilb@suse.de>
+ */
+
+#include <linux/exportfs.h>
+#include <linux/sunrpc/svcauth.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/nfs.h>
+#include <linux/nfs_common.h>
+#include <linux/nfslocalio.h>
+#include <linux/string.h>
+
+#include "nfsd.h"
+#include "vfs.h"
+#include "netns.h"
+#include "filecache.h"
+
+static const struct nfsd_localio_operations nfsd_localio_ops = {
+	.nfsd_open_local_fh = nfsd_open_local_fh,
+	.nfsd_file_put_local = nfsd_file_put_local,
+	.nfsd_file_file = nfsd_file_file,
+};
+
+void nfsd_localio_ops_init(void)
+{
+	memcpy(&nfs_to, &nfsd_localio_ops, sizeof(nfsd_localio_ops));
+}
+
+/**
+ * nfsd_open_local_fh - lookup a local filehandle @nfs_fh and map to nfsd_file
+ *
+ * @uuid: nfs_uuid_t which provides the 'struct net' to get the proper nfsd_net
+ *        and the 'struct auth_domain' required for LOCALIO access
+ * @rpc_clnt: rpc_clnt that the client established, used for sockaddr and cred
+ * @cred: cred that the client established
+ * @nfs_fh: filehandle to lookup
+ * @fmode: fmode_t to use for open
+ *
+ * This function maps a local fh to a path on a local filesystem.
+ * This is useful when the nfs client has the local server mounted - it can
+ * avoid all the NFS overhead with reads, writes and commits.
+ *
+ * On successful return, returned nfsd_file will have its nf_net member
+ * set. Caller (NFS client) is responsible for calling nfsd_serv_put and
+ * nfsd_file_put (via nfs_to.nfsd_file_put_local).
+ */
+struct nfsd_file *
+nfsd_open_local_fh(nfs_uuid_t *uuid,
+		   struct rpc_clnt *rpc_clnt, const struct cred *cred,
+		   const struct nfs_fh *nfs_fh, const fmode_t fmode)
+	__must_hold(rcu)
+{
+	int mayflags = NFSD_MAY_LOCALIO;
+	struct nfsd_net *nn = NULL;
+	struct net *net;
+	struct svc_cred rq_cred;
+	struct svc_fh fh;
+	struct nfsd_file *localio;
+	__be32 beres;
+
+	if (nfs_fh->size > NFS4_FHSIZE)
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * Not running in nfsd context, so must safely get reference on nfsd_serv.
+	 * But the server may already be shutting down, if so disallow new localio.
+	 * uuid->net is NOT a counted reference, but caller's rcu_read_lock() ensures
+	 * that if uuid->net is not NULL, then calling nfsd_serv_try_get() is safe
+	 * and if it succeeds we will have an implied reference to the net.
+	 */
+	net = rcu_dereference(uuid->net);
+	if (net)
+		nn = net_generic(net, nfsd_net_id);
+	if (unlikely(!nn || !nfsd_serv_try_get(nn)))
+		return ERR_PTR(-ENXIO);
+
+	/* Drop the rcu lock for nfsd_file_acquire_local() */
+	rcu_read_unlock();
+
+	/* nfs_fh -> svc_fh */
+	fh_init(&fh, NFS4_FHSIZE);
+	fh.fh_handle.fh_size = nfs_fh->size;
+	memcpy(fh.fh_handle.fh_raw, nfs_fh->data, nfs_fh->size);
+
+	if (fmode & FMODE_READ)
+		mayflags |= NFSD_MAY_READ;
+	if (fmode & FMODE_WRITE)
+		mayflags |= NFSD_MAY_WRITE;
+
+	svcauth_map_clnt_to_svc_cred_local(rpc_clnt, cred, &rq_cred);
+
+	beres = nfsd_file_acquire_local(uuid->net, &rq_cred, uuid->dom,
+					&fh, mayflags, &localio);
+	if (beres) {
+		localio = ERR_PTR(nfs_stat_to_errno(be32_to_cpu(beres)));
+		nfsd_serv_put(nn);
+	}
+
+	fh_put(&fh);
+	if (rq_cred.cr_group_info)
+		put_group_info(rq_cred.cr_group_info);
+
+	rcu_read_lock();
+	return localio;
+}
+EXPORT_SYMBOL_GPL(nfsd_open_local_fh);
diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index e2d953f21dde..0fd31188a951 100644
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h
@@ -216,6 +216,10 @@ struct nfsd_net {
 	/* last time an admin-revoke happened for NFSv4.0 */
 	time64_t		nfs40_last_revoke;
 
+#if IS_ENABLED(CONFIG_NFS_LOCALIO)
+	/* Local clients to be invalidated when net is shut down */
+	struct list_head	local_clients;
+#endif
 };
 
 /* Simple check to find out if a given net was properly initialized */
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 64c1b4d649bc..3adbc05ebaac 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -18,6 +18,7 @@
 #include <linux/sunrpc/svc.h>
 #include <linux/module.h>
 #include <linux/fsnotify.h>
+#include <linux/nfslocalio.h>
 
 #include "idmap.h"
 #include "nfsd.h"
@@ -2257,7 +2258,9 @@ static __net_init int nfsd_net_init(struct net *net)
 	get_random_bytes(&nn->siphash_key, sizeof(nn->siphash_key));
 	seqlock_init(&nn->writeverf_lock);
 	nfsd_proc_stat_init(net);
-
+#if IS_ENABLED(CONFIG_NFS_LOCALIO)
+	INIT_LIST_HEAD(&nn->local_clients);
+#endif
 	return 0;
 
 out_repcache_error:
@@ -2268,6 +2271,22 @@ static __net_init int nfsd_net_init(struct net *net)
 	return retval;
 }
 
+#if IS_ENABLED(CONFIG_NFS_LOCALIO)
+/**
+ * nfsd_net_pre_exit - Disconnect localio clients from net namespace
+ * @net: a network namespace that is about to be destroyed
+ *
+ * This invalidated ->net pointers held by localio clients
+ * while they can still safely access nn->counter.
+ */
+static __net_exit void nfsd_net_pre_exit(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	nfs_uuid_invalidate_clients(&nn->local_clients);
+}
+#endif
+
 /**
  * nfsd_net_exit - Release the nfsd_net portion of a net namespace
  * @net: a network namespace that is about to be destroyed
@@ -2285,6 +2304,9 @@ static __net_exit void nfsd_net_exit(struct net *net)
 
 static struct pernet_operations nfsd_net_ops = {
 	.init = nfsd_net_init,
+#if IS_ENABLED(CONFIG_NFS_LOCALIO)
+	.pre_exit = nfsd_net_pre_exit,
+#endif
 	.exit = nfsd_net_exit,
 	.id   = &nfsd_net_id,
 	.size = sizeof(struct nfsd_net),
@@ -2322,6 +2344,7 @@ static int __init init_nfsd(void)
 	retval = genl_register_family(&nfsd_nl_family);
 	if (retval)
 		goto out_free_all;
+	nfsd_localio_ops_init();
 
 	return 0;
 out_free_all:
diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
index d22027e23761..82bcefcd1f21 100644
--- a/fs/nfsd/trace.h
+++ b/fs/nfsd/trace.h
@@ -86,7 +86,8 @@ DEFINE_NFSD_XDR_ERR_EVENT(cant_encode);
 		{ NFSD_MAY_NOT_BREAK_LEASE,	"NOT_BREAK_LEASE" },	\
 		{ NFSD_MAY_BYPASS_GSS,		"BYPASS_GSS" },		\
 		{ NFSD_MAY_READ_IF_EXEC,	"READ_IF_EXEC" },	\
-		{ NFSD_MAY_64BIT_COOKIE,	"64BIT_COOKIE" })
+		{ NFSD_MAY_64BIT_COOKIE,	"64BIT_COOKIE" },	\
+		{ NFSD_MAY_LOCALIO,		"LOCALIO" })
 
 TRACE_EVENT(nfsd_compound,
 	TP_PROTO(
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index 01947561d375..3ff146522556 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -33,6 +33,8 @@
 
 #define NFSD_MAY_64BIT_COOKIE		0x1000 /* 64 bit readdir cookies for >= NFSv3 */
 
+#define NFSD_MAY_LOCALIO		0x2000 /* for tracing, reflects when localio used */
+
 #define NFSD_MAY_CREATE		(NFSD_MAY_EXEC|NFSD_MAY_WRITE)
 #define NFSD_MAY_REMOVE		(NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC)
 
diff --git a/include/linux/nfslocalio.h b/include/linux/nfslocalio.h
index 62419c4bc8f1..61f2c781dd50 100644
--- a/include/linux/nfslocalio.h
+++ b/include/linux/nfslocalio.h
@@ -6,6 +6,8 @@
 #ifndef __LINUX_NFSLOCALIO_H
 #define __LINUX_NFSLOCALIO_H
 
+#if IS_ENABLED(CONFIG_NFS_LOCALIO)
+
 #include <linux/module.h>
 #include <linux/list.h>
 #include <linux/uuid.h>
@@ -63,4 +65,10 @@ struct nfsd_localio_operations {
 extern void nfsd_localio_ops_init(void);
 extern struct nfsd_localio_operations nfs_to;
 
+#else   /* CONFIG_NFS_LOCALIO */
+static inline void nfsd_localio_ops_init(void)
+{
+}
+#endif  /* CONFIG_NFS_LOCALIO */
+
 #endif  /* __LINUX_NFSLOCALIO_H */
