diff --git a/fs/Kconfig b/fs/Kconfig
index a46b0cbc4d8f..1b8a5edbddff 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -377,6 +377,9 @@ config NFS_ACL_SUPPORT
 	tristate
 	select FS_POSIX_ACL
 
+config NFS_COMMON_LOCALIO_SUPPORT
+	bool
+
 config NFS_COMMON
 	bool
 	depends on NFSD || NFS_FS || LOCKD
diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
index c0bd1509ccd4..e6fa7eaa1db0 100644
--- a/fs/nfsd/Kconfig
+++ b/fs/nfsd/Kconfig
@@ -90,6 +90,22 @@ config NFSD_V4
 
 	  If unsure, say N.
 
+config NFSD_LOCALIO
+	bool "NFS server support for the LOCALIO auxiliary protocol"
+	depends on NFSD
+	select NFS_COMMON_LOCALIO_SUPPORT
+	default n
+	help
+	  Some NFS servers support an auxiliary NFS LOCALIO protocol
+	  that is not an official part of the NFS protocol.
+
+	  This option enables support for the LOCALIO protocol in the
+	  kernel's NFS server.  Enable this to permit local NFS clients
+	  to bypass the network when issuing reads and writes to the
+	  local NFS server.
+
+	  If unsure, say N.
+
 config NFSD_PNFS
 	bool
 
diff --git a/fs/nfsd/Makefile b/fs/nfsd/Makefile
index b8736a82e57c..78b421778a79 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_NFSD_LOCALIO) += localio.o
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index a83d469bca6b..49f4aab3208a 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -53,7 +53,7 @@
 #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..4b65c66be129
--- /dev/null
+++ b/fs/nfsd/localio.c
@@ -0,0 +1,105 @@
+// 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>
+ */
+
+#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"
+
+/**
+ * nfsd_open_local_fh - lookup a local filehandle @nfs_fh and map to nfsd_file
+ *
+ * @cl_nfssvc_net: the 'struct net' to use to get the proper nfsd_net
+ * @cl_nfssvc_dom: 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 nfs_localio_ctx will have its nfsd_file and
+ * nfsd_net members set. Caller is responsible for calling nfsd_file_put and
+ * nfsd_serv_put (via nfs_localio_ctx_free).
+ */
+struct nfs_localio_ctx *
+nfsd_open_local_fh(struct net *cl_nfssvc_net, struct auth_domain *cl_nfssvc_dom,
+		   struct rpc_clnt *rpc_clnt, const struct cred *cred,
+		   const struct nfs_fh *nfs_fh, const fmode_t fmode)
+{
+	int mayflags = NFSD_MAY_LOCALIO;
+	int status = 0;
+	struct nfsd_net *nn;
+	struct svc_cred rq_cred;
+	struct svc_fh fh;
+	struct nfs_localio_ctx *localio;
+	__be32 beres;
+
+	if (nfs_fh->size > NFS4_FHSIZE)
+		return ERR_PTR(-EINVAL);
+
+	localio = nfs_localio_ctx_alloc();
+	if (!localio)
+		return ERR_PTR(-ENOMEM);
+
+	/*
+	 * 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.
+	 */
+	nn = net_generic(cl_nfssvc_net, nfsd_net_id);
+	if (unlikely(!nfsd_serv_try_get(nn))) {
+		status = -ENXIO;
+		goto out_nfsd_serv;
+	}
+
+	/* 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(cl_nfssvc_net, &rq_cred, cl_nfssvc_dom,
+					&fh, mayflags, &localio->nf);
+	if (beres) {
+		status = nfs_stat_to_errno(be32_to_cpu(beres));
+		goto out_fh_put;
+	}
+	localio->nn = nn;
+
+out_fh_put:
+	fh_put(&fh);
+	if (rq_cred.cr_group_info)
+		put_group_info(rq_cred.cr_group_info);
+out_nfsd_serv:
+	if (status) {
+		nfs_localio_ctx_free(localio);
+		return ERR_PTR(status);
+	}
+	return localio;
+}
+EXPORT_SYMBOL_GPL(nfsd_open_local_fh);
+
+/* Compile time type checking, not used by anything */
+static nfs_to_nfsd_open_local_fh_t __maybe_unused nfsd_open_local_fh_typecheck = nfsd_open_local_fh;
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..e12310dd5f4c 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)
 
@@ -158,6 +160,11 @@ __be32		nfsd_permission(struct svc_cred *cred, struct svc_export *exp,
 
 void		nfsd_filp_close(struct file *fp);
 
+struct nfs_localio_ctx *
+nfsd_open_local_fh(struct net *, struct auth_domain *,
+		   struct rpc_clnt *, const struct cred *,
+		   const struct nfs_fh *, const fmode_t);
+
 static inline int fh_want_write(struct svc_fh *fh)
 {
 	int ret;
