1 files changed, 169 insertions, 0 deletions
diff --git a/fs/nfsd/localio.c b/fs/nfsd/localio.c
new file mode 100644
index 000000000000..291e9c69cae4
--- /dev/null
+++ b/fs/nfsd/localio.c
@@ -0,0 +1,169 @@
+// 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/nfs_fs.h>
+#include <linux/nfs_xdr.h>
+#include <linux/string.h>
+
+#include "nfsd.h"
+#include "vfs.h"
+#include "netns.h"
+#include "filecache.h"
+#include "cache.h"
+
+static const struct nfsd_localio_operations nfsd_localio_ops = {
+	.nfsd_serv_try_get  = nfsd_serv_try_get,
+	.nfsd_serv_put  = nfsd_serv_put,
+	.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)
+{
+	nfs_to = &nfsd_localio_ops;
+}
+
+/**
+ * nfsd_open_local_fh - lookup a local filehandle @nfs_fh and map to nfsd_file
+ *
+ * @net: 'struct net' to get the proper nfsd_net required for LOCALIO access
+ * @dom: 'struct auth_domain' required for LOCALIO access
+ * @rpc_clnt: rpc_clnt that the client established
+ * @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(struct net *net, struct auth_domain *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;
+	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);
+
+	/* 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(net, &rq_cred, dom,
+					&fh, mayflags, &localio);
+	if (beres)
+		localio = ERR_PTR(nfs_stat_to_errno(be32_to_cpu(beres)));
+
+	fh_put(&fh);
+	if (rq_cred.cr_group_info)
+		put_group_info(rq_cred.cr_group_info);
+
+	return localio;
+}
+EXPORT_SYMBOL_GPL(nfsd_open_local_fh);
+
+/*
+ * UUID_IS_LOCAL XDR functions
+ */
+
+static __be32 localio_proc_null(struct svc_rqst *rqstp)
+{
+	return rpc_success;
+}
+
+struct localio_uuidarg {
+	uuid_t			uuid;
+};
+
+static __be32 localio_proc_uuid_is_local(struct svc_rqst *rqstp)
+{
+	struct localio_uuidarg *argp = rqstp->rq_argp;
+	struct net *net = SVC_NET(rqstp);
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	nfs_uuid_is_local(&argp->uuid, &nn->local_clients,
+			  net, rqstp->rq_client, THIS_MODULE);
+
+	return rpc_success;
+}
+
+static bool localio_decode_uuidarg(struct svc_rqst *rqstp,
+				   struct xdr_stream *xdr)
+{
+	struct localio_uuidarg *argp = rqstp->rq_argp;
+	u8 uuid[UUID_SIZE];
+
+	if (decode_opaque_fixed(xdr, uuid, UUID_SIZE))
+		return false;
+	import_uuid(&argp->uuid, uuid);
+
+	return true;
+}
+
+static const struct svc_procedure localio_procedures1[] = {
+	[LOCALIOPROC_NULL] = {
+		.pc_func = localio_proc_null,
+		.pc_decode = nfssvc_decode_voidarg,
+		.pc_encode = nfssvc_encode_voidres,
+		.pc_argsize = sizeof(struct nfsd_voidargs),
+		.pc_ressize = sizeof(struct nfsd_voidres),
+		.pc_cachetype = RC_NOCACHE,
+		.pc_xdrressize = 0,
+		.pc_name = "NULL",
+	},
+	[LOCALIOPROC_UUID_IS_LOCAL] = {
+		.pc_func = localio_proc_uuid_is_local,
+		.pc_decode = localio_decode_uuidarg,
+		.pc_encode = nfssvc_encode_voidres,
+		.pc_argsize = sizeof(struct localio_uuidarg),
+		.pc_argzero = sizeof(struct localio_uuidarg),
+		.pc_ressize = sizeof(struct nfsd_voidres),
+		.pc_cachetype = RC_NOCACHE,
+		.pc_name = "UUID_IS_LOCAL",
+	},
+};
+
+#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,
+};