Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1390 insertions, 0 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
new file mode 100644
index 000000000..f50e025ae
--- /dev/null
+++ b/fs/nfs/client.c
@@ -0,0 +1,1390 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* client.c: NFS client sharing and management code
+ *
+ * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/time.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/unistd.h>
+#include <linux/sunrpc/addr.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/stats.h>
+#include <linux/sunrpc/metrics.h>
+#include <linux/sunrpc/xprtsock.h>
+#include <linux/sunrpc/xprtrdma.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/nfs4_mount.h>
+#include <linux/lockd/bind.h>
+#include <linux/seq_file.h>
+#include <linux/mount.h>
+#include <linux/vfs.h>
+#include <linux/inet.h>
+#include <linux/in6.h>
+#include <linux/slab.h>
+#include <linux/idr.h>
+#include <net/ipv6.h>
+#include <linux/nfs_xdr.h>
+#include <linux/sunrpc/bc_xprt.h>
+#include <linux/nsproxy.h>
+#include <linux/pid_namespace.h>
+
+
+#include "nfs4_fs.h"
+#include "callback.h"
+#include "delegation.h"
+#include "iostat.h"
+#include "internal.h"
+#include "fscache.h"
+#include "pnfs.h"
+#include "nfs.h"
+#include "netns.h"
+#include "sysfs.h"
+#include "nfs42.h"
+
+#define NFSDBG_FACILITY		NFSDBG_CLIENT
+
+static DECLARE_WAIT_QUEUE_HEAD(nfs_client_active_wq);
+static DEFINE_SPINLOCK(nfs_version_lock);
+static DEFINE_MUTEX(nfs_version_mutex);
+static LIST_HEAD(nfs_versions);
+
+/*
+ * RPC cruft for NFS
+ */
+static const struct rpc_version *nfs_version[5] = {
+	[2] = NULL,
+	[3] = NULL,
+	[4] = NULL,
+};
+
+const struct rpc_program nfs_program = {
+	.name			= "nfs",
+	.number			= NFS_PROGRAM,
+	.nrvers			= ARRAY_SIZE(nfs_version),
+	.version		= nfs_version,
+	.stats			= &nfs_rpcstat,
+	.pipe_dir_name		= NFS_PIPE_DIRNAME,
+};
+
+struct rpc_stat nfs_rpcstat = {
+	.program		= &nfs_program
+};
+
+static struct nfs_subversion *find_nfs_version(unsigned int version)
+{
+	struct nfs_subversion *nfs;
+	spin_lock(&nfs_version_lock);
+
+	list_for_each_entry(nfs, &nfs_versions, list) {
+		if (nfs->rpc_ops->version == version) {
+			spin_unlock(&nfs_version_lock);
+			return nfs;
+		}
+	}
+
+	spin_unlock(&nfs_version_lock);
+	return ERR_PTR(-EPROTONOSUPPORT);
+}
+
+struct nfs_subversion *get_nfs_version(unsigned int version)
+{
+	struct nfs_subversion *nfs = find_nfs_version(version);
+
+	if (IS_ERR(nfs)) {
+		mutex_lock(&nfs_version_mutex);
+		request_module("nfsv%d", version);
+		nfs = find_nfs_version(version);
+		mutex_unlock(&nfs_version_mutex);
+	}
+
+	if (!IS_ERR(nfs) && !try_module_get(nfs->owner))
+		return ERR_PTR(-EAGAIN);
+	return nfs;
+}
+
+void put_nfs_version(struct nfs_subversion *nfs)
+{
+	module_put(nfs->owner);
+}
+
+void register_nfs_version(struct nfs_subversion *nfs)
+{
+	spin_lock(&nfs_version_lock);
+
+	list_add(&nfs->list, &nfs_versions);
+	nfs_version[nfs->rpc_ops->version] = nfs->rpc_vers;
+
+	spin_unlock(&nfs_version_lock);
+}
+EXPORT_SYMBOL_GPL(register_nfs_version);
+
+void unregister_nfs_version(struct nfs_subversion *nfs)
+{
+	spin_lock(&nfs_version_lock);
+
+	nfs_version[nfs->rpc_ops->version] = NULL;
+	list_del(&nfs->list);
+
+	spin_unlock(&nfs_version_lock);
+}
+EXPORT_SYMBOL_GPL(unregister_nfs_version);
+
+/*
+ * Allocate a shared client record
+ *
+ * Since these are allocated/deallocated very rarely, we don't
+ * bother putting them in a slab cache...
+ */
+struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_init)
+{
+	struct nfs_client *clp;
+	int err = -ENOMEM;
+
+	if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
+		goto error_0;
+
+	clp->cl_minorversion = cl_init->minorversion;
+	clp->cl_nfs_mod = cl_init->nfs_mod;
+	if (!try_module_get(clp->cl_nfs_mod->owner))
+		goto error_dealloc;
+
+	clp->rpc_ops = clp->cl_nfs_mod->rpc_ops;
+
+	refcount_set(&clp->cl_count, 1);
+	clp->cl_cons_state = NFS_CS_INITING;
+
+	memcpy(&clp->cl_addr, cl_init->addr, cl_init->addrlen);
+	clp->cl_addrlen = cl_init->addrlen;
+
+	if (cl_init->hostname) {
+		err = -ENOMEM;
+		clp->cl_hostname = kstrdup(cl_init->hostname, GFP_KERNEL);
+		if (!clp->cl_hostname)
+			goto error_cleanup;
+	}
+
+	INIT_LIST_HEAD(&clp->cl_superblocks);
+	clp->cl_rpcclient = ERR_PTR(-EINVAL);
+
+	clp->cl_flags = cl_init->init_flags;
+	clp->cl_proto = cl_init->proto;
+	clp->cl_nconnect = cl_init->nconnect;
+	clp->cl_max_connect = cl_init->max_connect ? cl_init->max_connect : 1;
+	clp->cl_net = get_net(cl_init->net);
+
+	clp->cl_principal = "*";
+	return clp;
+
+error_cleanup:
+	put_nfs_version(clp->cl_nfs_mod);
+error_dealloc:
+	kfree(clp);
+error_0:
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(nfs_alloc_client);
+
+#if IS_ENABLED(CONFIG_NFS_V4)
+static void nfs_cleanup_cb_ident_idr(struct net *net)
+{
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
+
+	idr_destroy(&nn->cb_ident_idr);
+}
+
+/* nfs_client_lock held */
+static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
+{
+	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
+
+	if (clp->cl_cb_ident)
+		idr_remove(&nn->cb_ident_idr, clp->cl_cb_ident);
+}
+
+static void pnfs_init_server(struct nfs_server *server)
+{
+	rpc_init_wait_queue(&server->roc_rpcwaitq, "pNFS ROC");
+}
+
+#else
+static void nfs_cleanup_cb_ident_idr(struct net *net)
+{
+}
+
+static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
+{
+}
+
+static void pnfs_init_server(struct nfs_server *server)
+{
+}
+
+#endif /* CONFIG_NFS_V4 */
+
+/*
+ * Destroy a shared client record
+ */
+void nfs_free_client(struct nfs_client *clp)
+{
+	/* -EIO all pending I/O */
+	if (!IS_ERR(clp->cl_rpcclient))
+		rpc_shutdown_client(clp->cl_rpcclient);
+
+	put_net(clp->cl_net);
+	put_nfs_version(clp->cl_nfs_mod);
+	kfree(clp->cl_hostname);
+	kfree(clp->cl_acceptor);
+	kfree(clp);
+}
+EXPORT_SYMBOL_GPL(nfs_free_client);
+
+/*
+ * Release a reference to a shared client record
+ */
+void nfs_put_client(struct nfs_client *clp)
+{
+	struct nfs_net *nn;
+
+	if (!clp)
+		return;
+
+	nn = net_generic(clp->cl_net, nfs_net_id);
+
+	if (refcount_dec_and_lock(&clp->cl_count, &nn->nfs_client_lock)) {
+		list_del(&clp->cl_share_link);
+		nfs_cb_idr_remove_locked(clp);
+		spin_unlock(&nn->nfs_client_lock);
+
+		WARN_ON_ONCE(!list_empty(&clp->cl_superblocks));
+
+		clp->rpc_ops->free_client(clp);
+	}
+}
+EXPORT_SYMBOL_GPL(nfs_put_client);
+
+/*
+ * Find an nfs_client on the list that matches the initialisation data
+ * that is supplied.
+ */
+static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *data)
+{
+	struct nfs_client *clp;
+	const struct sockaddr *sap = (struct sockaddr *)data->addr;
+	struct nfs_net *nn = net_generic(data->net, nfs_net_id);
+	int error;
+
+again:
+	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
+	        const struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
+		/* Don't match clients that failed to initialise properly */
+		if (clp->cl_cons_state < 0)
+			continue;
+
+		/* If a client is still initializing then we need to wait */
+		if (clp->cl_cons_state > NFS_CS_READY) {
+			refcount_inc(&clp->cl_count);
+			spin_unlock(&nn->nfs_client_lock);
+			error = nfs_wait_client_init_complete(clp);
+			nfs_put_client(clp);
+			spin_lock(&nn->nfs_client_lock);
+			if (error < 0)
+				return ERR_PTR(error);
+			goto again;
+		}
+
+		/* Different NFS versions cannot share the same nfs_client */
+		if (clp->rpc_ops != data->nfs_mod->rpc_ops)
+			continue;
+
+		if (clp->cl_proto != data->proto)
+			continue;
+		/* Match nfsv4 minorversion */
+		if (clp->cl_minorversion != data->minorversion)
+			continue;
+
+		/* Match request for a dedicated DS */
+		if (test_bit(NFS_CS_DS, &data->init_flags) !=
+		    test_bit(NFS_CS_DS, &clp->cl_flags))
+			continue;
+
+		/* Match the full socket address */
+		if (!rpc_cmp_addr_port(sap, clap))
+			/* Match all xprt_switch full socket addresses */
+			if (IS_ERR(clp->cl_rpcclient) ||
+                            !rpc_clnt_xprt_switch_has_addr(clp->cl_rpcclient,
+							   sap))
+				continue;
+
+		refcount_inc(&clp->cl_count);
+		return clp;
+	}
+	return NULL;
+}
+
+/*
+ * Return true if @clp is done initializing, false if still working on it.
+ *
+ * Use nfs_client_init_status to check if it was successful.
+ */
+bool nfs_client_init_is_complete(const struct nfs_client *clp)
+{
+	return clp->cl_cons_state <= NFS_CS_READY;
+}
+EXPORT_SYMBOL_GPL(nfs_client_init_is_complete);
+
+/*
+ * Return 0 if @clp was successfully initialized, -errno otherwise.
+ *
+ * This must be called *after* nfs_client_init_is_complete() returns true,
+ * otherwise it will pop WARN_ON_ONCE and return -EINVAL
+ */
+int nfs_client_init_status(const struct nfs_client *clp)
+{
+	/* called without checking nfs_client_init_is_complete */
+	if (clp->cl_cons_state > NFS_CS_READY) {
+		WARN_ON_ONCE(1);
+		return -EINVAL;
+	}
+	return clp->cl_cons_state;
+}
+EXPORT_SYMBOL_GPL(nfs_client_init_status);
+
+int nfs_wait_client_init_complete(const struct nfs_client *clp)
+{
+	return wait_event_killable(nfs_client_active_wq,
+			nfs_client_init_is_complete(clp));
+}
+EXPORT_SYMBOL_GPL(nfs_wait_client_init_complete);
+
+/*
+ * Found an existing client.  Make sure it's ready before returning.
+ */
+static struct nfs_client *
+nfs_found_client(const struct nfs_client_initdata *cl_init,
+		 struct nfs_client *clp)
+{
+	int error;
+
+	error = nfs_wait_client_init_complete(clp);
+	if (error < 0) {
+		nfs_put_client(clp);
+		return ERR_PTR(-ERESTARTSYS);
+	}
+
+	if (clp->cl_cons_state < NFS_CS_READY) {
+		error = clp->cl_cons_state;
+		nfs_put_client(clp);
+		return ERR_PTR(error);
+	}
+
+	smp_rmb();
+	return clp;
+}
+
+/*
+ * Look up a client by IP address and protocol version
+ * - creates a new record if one doesn't yet exist
+ */
+struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_init)
+{
+	struct nfs_client *clp, *new = NULL;
+	struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
+	const struct nfs_rpc_ops *rpc_ops = cl_init->nfs_mod->rpc_ops;
+
+	if (cl_init->hostname == NULL) {
+		WARN_ON(1);
+		return ERR_PTR(-EINVAL);
+	}
+
+	/* see if the client already exists */
+	do {
+		spin_lock(&nn->nfs_client_lock);
+
+		clp = nfs_match_client(cl_init);
+		if (clp) {
+			spin_unlock(&nn->nfs_client_lock);
+			if (new)
+				new->rpc_ops->free_client(new);
+			if (IS_ERR(clp))
+				return clp;
+			return nfs_found_client(cl_init, clp);
+		}
+		if (new) {
+			list_add_tail(&new->cl_share_link,
+					&nn->nfs_client_list);
+			spin_unlock(&nn->nfs_client_lock);
+			return rpc_ops->init_client(new, cl_init);
+		}
+
+		spin_unlock(&nn->nfs_client_lock);
+
+		new = rpc_ops->alloc_client(cl_init);
+	} while (!IS_ERR(new));
+
+	return new;
+}
+EXPORT_SYMBOL_GPL(nfs_get_client);
+
+/*
+ * Mark a server as ready or failed
+ */
+void nfs_mark_client_ready(struct nfs_client *clp, int state)
+{
+	smp_wmb();
+	clp->cl_cons_state = state;
+	wake_up_all(&nfs_client_active_wq);
+}
+EXPORT_SYMBOL_GPL(nfs_mark_client_ready);
+
+/*
+ * Initialise the timeout values for a connection
+ */
+void nfs_init_timeout_values(struct rpc_timeout *to, int proto,
+				    int timeo, int retrans)
+{
+	to->to_initval = timeo * HZ / 10;
+	to->to_retries = retrans;
+
+	switch (proto) {
+	case XPRT_TRANSPORT_TCP:
+	case XPRT_TRANSPORT_RDMA:
+		if (retrans == NFS_UNSPEC_RETRANS)
+			to->to_retries = NFS_DEF_TCP_RETRANS;
+		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
+			to->to_initval = NFS_DEF_TCP_TIMEO * HZ / 10;
+		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
+			to->to_initval = NFS_MAX_TCP_TIMEOUT;
+		to->to_increment = to->to_initval;
+		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
+		if (to->to_maxval > NFS_MAX_TCP_TIMEOUT)
+			to->to_maxval = NFS_MAX_TCP_TIMEOUT;
+		if (to->to_maxval < to->to_initval)
+			to->to_maxval = to->to_initval;
+		to->to_exponential = 0;
+		break;
+	case XPRT_TRANSPORT_UDP:
+		if (retrans == NFS_UNSPEC_RETRANS)
+			to->to_retries = NFS_DEF_UDP_RETRANS;
+		if (timeo == NFS_UNSPEC_TIMEO || to->to_initval == 0)
+			to->to_initval = NFS_DEF_UDP_TIMEO * HZ / 10;
+		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
+			to->to_initval = NFS_MAX_UDP_TIMEOUT;
+		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
+		to->to_exponential = 1;
+		break;
+	default:
+		BUG();
+	}
+}
+EXPORT_SYMBOL_GPL(nfs_init_timeout_values);
+
+/*
+ * Create an RPC client handle
+ */
+int nfs_create_rpc_client(struct nfs_client *clp,
+			  const struct nfs_client_initdata *cl_init,
+			  rpc_authflavor_t flavor)
+{
+	struct rpc_clnt		*clnt = NULL;
+	struct rpc_create_args args = {
+		.net		= clp->cl_net,
+		.protocol	= clp->cl_proto,
+		.nconnect	= clp->cl_nconnect,
+		.address	= (struct sockaddr *)&clp->cl_addr,
+		.addrsize	= clp->cl_addrlen,
+		.timeout	= cl_init->timeparms,
+		.servername	= clp->cl_hostname,
+		.nodename	= cl_init->nodename,
+		.program	= &nfs_program,
+		.version	= clp->rpc_ops->version,
+		.authflavor	= flavor,
+		.cred		= cl_init->cred,
+	};
+
+	if (test_bit(NFS_CS_DISCRTRY, &clp->cl_flags))
+		args.flags |= RPC_CLNT_CREATE_DISCRTRY;
+	if (test_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags))
+		args.flags |= RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT;
+	if (test_bit(NFS_CS_NORESVPORT, &clp->cl_flags))
+		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
+	if (test_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags))
+		args.flags |= RPC_CLNT_CREATE_INFINITE_SLOTS;
+	if (test_bit(NFS_CS_NOPING, &clp->cl_flags))
+		args.flags |= RPC_CLNT_CREATE_NOPING;
+	if (test_bit(NFS_CS_REUSEPORT, &clp->cl_flags))
+		args.flags |= RPC_CLNT_CREATE_REUSEPORT;
+
+	if (!IS_ERR(clp->cl_rpcclient))
+		return 0;
+
+	clnt = rpc_create(&args);
+	if (IS_ERR(clnt)) {
+		dprintk("%s: cannot create RPC client. Error = %ld\n",
+				__func__, PTR_ERR(clnt));
+		return PTR_ERR(clnt);
+	}
+
+	clnt->cl_principal = clp->cl_principal;
+	clp->cl_rpcclient = clnt;
+	clnt->cl_max_connect = clp->cl_max_connect;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nfs_create_rpc_client);
+
+/*
+ * Version 2 or 3 client destruction
+ */
+static void nfs_destroy_server(struct nfs_server *server)
+{
+	if (server->nlm_host)
+		nlmclnt_done(server->nlm_host);
+}
+
+/*
+ * Version 2 or 3 lockd setup
+ */
+static int nfs_start_lockd(struct nfs_server *server)
+{
+	struct nlm_host *host;
+	struct nfs_client *clp = server->nfs_client;
+	struct nlmclnt_initdata nlm_init = {
+		.hostname	= clp->cl_hostname,
+		.address	= (struct sockaddr *)&clp->cl_addr,
+		.addrlen	= clp->cl_addrlen,
+		.nfs_version	= clp->rpc_ops->version,
+		.noresvport	= server->flags & NFS_MOUNT_NORESVPORT ?
+					1 : 0,
+		.net		= clp->cl_net,
+		.nlmclnt_ops 	= clp->cl_nfs_mod->rpc_ops->nlmclnt_ops,
+		.cred		= server->cred,
+	};
+
+	if (nlm_init.nfs_version > 3)
+		return 0;
+	if ((server->flags & NFS_MOUNT_LOCAL_FLOCK) &&
+			(server->flags & NFS_MOUNT_LOCAL_FCNTL))
+		return 0;
+
+	switch (clp->cl_proto) {
+		default:
+			nlm_init.protocol = IPPROTO_TCP;
+			break;
+#ifndef CONFIG_NFS_DISABLE_UDP_SUPPORT
+		case XPRT_TRANSPORT_UDP:
+			nlm_init.protocol = IPPROTO_UDP;
+#endif
+	}
+
+	host = nlmclnt_init(&nlm_init);
+	if (IS_ERR(host))
+		return PTR_ERR(host);
+
+	server->nlm_host = host;
+	server->destroy = nfs_destroy_server;
+	return 0;
+}
+
+/*
+ * Create a general RPC client
+ */
+int nfs_init_server_rpcclient(struct nfs_server *server,
+		const struct rpc_timeout *timeo,
+		rpc_authflavor_t pseudoflavour)
+{
+	struct nfs_client *clp = server->nfs_client;
+
+	server->client = rpc_clone_client_set_auth(clp->cl_rpcclient,
+							pseudoflavour);
+	if (IS_ERR(server->client)) {
+		dprintk("%s: couldn't create rpc_client!\n", __func__);
+		return PTR_ERR(server->client);
+	}
+
+	memcpy(&server->client->cl_timeout_default,
+			timeo,
+			sizeof(server->client->cl_timeout_default));
+	server->client->cl_timeout = &server->client->cl_timeout_default;
+	server->client->cl_softrtry = 0;
+	if (server->flags & NFS_MOUNT_SOFTERR)
+		server->client->cl_softerr = 1;
+	if (server->flags & NFS_MOUNT_SOFT)
+		server->client->cl_softrtry = 1;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nfs_init_server_rpcclient);
+
+/**
+ * nfs_init_client - Initialise an NFS2 or NFS3 client
+ *
+ * @clp: nfs_client to initialise
+ * @cl_init: Initialisation parameters
+ *
+ * Returns pointer to an NFS client, or an ERR_PTR value.
+ */
+struct nfs_client *nfs_init_client(struct nfs_client *clp,
+				   const struct nfs_client_initdata *cl_init)
+{
+	int error;
+
+	/* the client is already initialised */
+	if (clp->cl_cons_state == NFS_CS_READY)
+		return clp;
+
+	/*
+	 * Create a client RPC handle for doing FSSTAT with UNIX auth only
+	 * - RFC 2623, sec 2.3.2
+	 */
+	error = nfs_create_rpc_client(clp, cl_init, RPC_AUTH_UNIX);
+	nfs_mark_client_ready(clp, error == 0 ? NFS_CS_READY : error);
+	if (error < 0) {
+		nfs_put_client(clp);
+		clp = ERR_PTR(error);
+	}
+	return clp;
+}
+EXPORT_SYMBOL_GPL(nfs_init_client);
+
+/*
+ * Create a version 2 or 3 client
+ */
+static int nfs_init_server(struct nfs_server *server,
+			   const struct fs_context *fc)
+{
+	const struct nfs_fs_context *ctx = nfs_fc2context(fc);
+	struct rpc_timeout timeparms;
+	struct nfs_client_initdata cl_init = {
+		.hostname = ctx->nfs_server.hostname,
+		.addr = &ctx->nfs_server._address,
+		.addrlen = ctx->nfs_server.addrlen,
+		.nfs_mod = ctx->nfs_mod,
+		.proto = ctx->nfs_server.protocol,
+		.net = fc->net_ns,
+		.timeparms = &timeparms,
+		.cred = server->cred,
+		.nconnect = ctx->nfs_server.nconnect,
+		.init_flags = (1UL << NFS_CS_REUSEPORT),
+	};
+	struct nfs_client *clp;
+	int error;
+
+	nfs_init_timeout_values(&timeparms, ctx->nfs_server.protocol,
+				ctx->timeo, ctx->retrans);
+	if (ctx->flags & NFS_MOUNT_NORESVPORT)
+		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
+
+	/* Allocate or find a client reference we can use */
+	clp = nfs_get_client(&cl_init);
+	if (IS_ERR(clp))
+		return PTR_ERR(clp);
+
+	server->nfs_client = clp;
+
+	/* Initialise the client representation from the mount data */
+	server->flags = ctx->flags;
+	server->options = ctx->options;
+	server->caps |= NFS_CAP_HARDLINKS | NFS_CAP_SYMLINKS;
+
+	switch (clp->rpc_ops->version) {
+	case 2:
+		server->fattr_valid = NFS_ATTR_FATTR_V2;
+		break;
+	case 3:
+		server->fattr_valid = NFS_ATTR_FATTR_V3;
+		break;
+	default:
+		server->fattr_valid = NFS_ATTR_FATTR_V4;
+	}
+
+	if (ctx->rsize)
+		server->rsize = nfs_io_size(ctx->rsize, clp->cl_proto);
+	if (ctx->wsize)
+		server->wsize = nfs_io_size(ctx->wsize, clp->cl_proto);
+
+	server->acregmin = ctx->acregmin * HZ;
+	server->acregmax = ctx->acregmax * HZ;
+	server->acdirmin = ctx->acdirmin * HZ;
+	server->acdirmax = ctx->acdirmax * HZ;
+
+	/* Start lockd here, before we might error out */
+	error = nfs_start_lockd(server);
+	if (error < 0)
+		goto error;
+
+	server->port = ctx->nfs_server.port;
+	server->auth_info = ctx->auth_info;
+
+	error = nfs_init_server_rpcclient(server, &timeparms,
+					  ctx->selected_flavor);
+	if (error < 0)
+		goto error;
+
+	/* Preserve the values of mount_server-related mount options */
+	if (ctx->mount_server.addrlen) {
+		memcpy(&server->mountd_address, &ctx->mount_server.address,
+			ctx->mount_server.addrlen);
+		server->mountd_addrlen = ctx->mount_server.addrlen;
+	}
+	server->mountd_version = ctx->mount_server.version;
+	server->mountd_port = ctx->mount_server.port;
+	server->mountd_protocol = ctx->mount_server.protocol;
+
+	server->namelen  = ctx->namlen;
+	return 0;
+
+error:
+	server->nfs_client = NULL;
+	nfs_put_client(clp);
+	return error;
+}
+
+/*
+ * Load up the server record from information gained in an fsinfo record
+ */
+static void nfs_server_set_fsinfo(struct nfs_server *server,
+				  struct nfs_fsinfo *fsinfo)
+{
+	struct nfs_client *clp = server->nfs_client;
+	unsigned long max_rpc_payload, raw_max_rpc_payload;
+
+	/* Work out a lot of parameters */
+	if (server->rsize == 0)
+		server->rsize = nfs_io_size(fsinfo->rtpref, clp->cl_proto);
+	if (server->wsize == 0)
+		server->wsize = nfs_io_size(fsinfo->wtpref, clp->cl_proto);
+
+	if (fsinfo->rtmax >= 512 && server->rsize > fsinfo->rtmax)
+		server->rsize = nfs_io_size(fsinfo->rtmax, clp->cl_proto);
+	if (fsinfo->wtmax >= 512 && server->wsize > fsinfo->wtmax)
+		server->wsize = nfs_io_size(fsinfo->wtmax, clp->cl_proto);
+
+	raw_max_rpc_payload = rpc_max_payload(server->client);
+	max_rpc_payload = nfs_block_size(raw_max_rpc_payload, NULL);
+
+	if (server->rsize > max_rpc_payload)
+		server->rsize = max_rpc_payload;
+	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
+		server->rsize = NFS_MAX_FILE_IO_SIZE;
+	server->rpages = (server->rsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+	if (server->wsize > max_rpc_payload)
+		server->wsize = max_rpc_payload;
+	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
+		server->wsize = NFS_MAX_FILE_IO_SIZE;
+	server->wpages = (server->wsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
+
+	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
+	if (server->dtsize > NFS_MAX_FILE_IO_SIZE)
+		server->dtsize = NFS_MAX_FILE_IO_SIZE;
+	if (server->dtsize > server->rsize)
+		server->dtsize = server->rsize;
+
+	if (server->flags & NFS_MOUNT_NOAC) {
+		server->acregmin = server->acregmax = 0;
+		server->acdirmin = server->acdirmax = 0;
+	}
+
+	server->maxfilesize = fsinfo->maxfilesize;
+
+	server->time_delta = fsinfo->time_delta;
+	server->change_attr_type = fsinfo->change_attr_type;
+
+	server->clone_blksize = fsinfo->clone_blksize;
+	/* We're airborne Set socket buffersize */
+	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
+
+#ifdef CONFIG_NFS_V4_2
+	/*
+	 * Defaults until limited by the session parameters.
+	 */
+	server->gxasize = min_t(unsigned int, raw_max_rpc_payload,
+				XATTR_SIZE_MAX);
+	server->sxasize = min_t(unsigned int, raw_max_rpc_payload,
+				XATTR_SIZE_MAX);
+	server->lxasize = min_t(unsigned int, raw_max_rpc_payload,
+				nfs42_listxattr_xdrsize(XATTR_LIST_MAX));
+
+	if (fsinfo->xattr_support)
+		server->caps |= NFS_CAP_XATTR;
+#endif
+}
+
+/*
+ * Probe filesystem information, including the FSID on v2/v3
+ */
+static int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs_fattr *fattr)
+{
+	struct nfs_fsinfo fsinfo;
+	struct nfs_client *clp = server->nfs_client;
+	int error;
+
+	if (clp->rpc_ops->set_capabilities != NULL) {
+		error = clp->rpc_ops->set_capabilities(server, mntfh);
+		if (error < 0)
+			return error;
+	}
+
+	fsinfo.fattr = fattr;
+	fsinfo.nlayouttypes = 0;
+	memset(fsinfo.layouttype, 0, sizeof(fsinfo.layouttype));
+	error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
+	if (error < 0)
+		return error;
+
+	nfs_server_set_fsinfo(server, &fsinfo);
+
+	/* Get some general file system info */
+	if (server->namelen == 0) {
+		struct nfs_pathconf pathinfo;
+
+		pathinfo.fattr = fattr;
+		nfs_fattr_init(fattr);
+
+		if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0)
+			server->namelen = pathinfo.max_namelen;
+	}
+
+	if (clp->rpc_ops->discover_trunking != NULL &&
+			(server->caps & NFS_CAP_FS_LOCATIONS &&
+			 (server->flags & NFS_MOUNT_TRUNK_DISCOVERY))) {
+		error = clp->rpc_ops->discover_trunking(server, mntfh);
+		if (error < 0)
+			return error;
+	}
+
+	return 0;
+}
+
+/*
+ * Grab the destination's particulars, including lease expiry time.
+ *
+ * Returns zero if probe succeeded and retrieved FSID matches the FSID
+ * we have cached.
+ */
+int nfs_probe_server(struct nfs_server *server, struct nfs_fh *mntfh)
+{
+	struct nfs_fattr *fattr;
+	int error;
+
+	fattr = nfs_alloc_fattr();
+	if (fattr == NULL)
+		return -ENOMEM;
+
+	/* Sanity: the probe won't work if the destination server
+	 * does not recognize the migrated FH. */
+	error = nfs_probe_fsinfo(server, mntfh, fattr);
+
+	nfs_free_fattr(fattr);
+	return error;
+}
+EXPORT_SYMBOL_GPL(nfs_probe_server);
+
+/*
+ * Copy useful information when duplicating a server record
+ */
+void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_server *source)
+{
+	target->flags = source->flags;
+	target->rsize = source->rsize;
+	target->wsize = source->wsize;
+	target->acregmin = source->acregmin;
+	target->acregmax = source->acregmax;
+	target->acdirmin = source->acdirmin;
+	target->acdirmax = source->acdirmax;
+	target->caps = source->caps;
+	target->options = source->options;
+	target->auth_info = source->auth_info;
+	target->port = source->port;
+}
+EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);
+
+void nfs_server_insert_lists(struct nfs_server *server)
+{
+	struct nfs_client *clp = server->nfs_client;
+	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
+
+	spin_lock(&nn->nfs_client_lock);
+	list_add_tail_rcu(&server->client_link, &clp->cl_superblocks);
+	list_add_tail(&server->master_link, &nn->nfs_volume_list);
+	clear_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
+	spin_unlock(&nn->nfs_client_lock);
+
+}
+EXPORT_SYMBOL_GPL(nfs_server_insert_lists);
+
+void nfs_server_remove_lists(struct nfs_server *server)
+{
+	struct nfs_client *clp = server->nfs_client;
+	struct nfs_net *nn;
+
+	if (clp == NULL)
+		return;
+	nn = net_generic(clp->cl_net, nfs_net_id);
+	spin_lock(&nn->nfs_client_lock);
+	list_del_rcu(&server->client_link);
+	if (list_empty(&clp->cl_superblocks))
+		set_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
+	list_del(&server->master_link);
+	spin_unlock(&nn->nfs_client_lock);
+
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(nfs_server_remove_lists);
+
+/*
+ * Allocate and initialise a server record
+ */
+struct nfs_server *nfs_alloc_server(void)
+{
+	struct nfs_server *server;
+
+	server = kzalloc(sizeof(struct nfs_server), GFP_KERNEL);
+	if (!server)
+		return NULL;
+
+	server->client = server->client_acl = ERR_PTR(-EINVAL);
+
+	/* Zero out the NFS state stuff */
+	INIT_LIST_HEAD(&server->client_link);
+	INIT_LIST_HEAD(&server->master_link);
+	INIT_LIST_HEAD(&server->delegations);
+	INIT_LIST_HEAD(&server->layouts);
+	INIT_LIST_HEAD(&server->state_owners_lru);
+	INIT_LIST_HEAD(&server->ss_copies);
+
+	atomic_set(&server->active, 0);
+
+	server->io_stats = nfs_alloc_iostats();
+	if (!server->io_stats) {
+		kfree(server);
+		return NULL;
+	}
+
+	server->change_attr_type = NFS4_CHANGE_TYPE_IS_UNDEFINED;
+
+	ida_init(&server->openowner_id);
+	ida_init(&server->lockowner_id);
+	pnfs_init_server(server);
+	rpc_init_wait_queue(&server->uoc_rpcwaitq, "NFS UOC");
+
+	return server;
+}
+EXPORT_SYMBOL_GPL(nfs_alloc_server);
+
+/*
+ * Free up a server record
+ */
+void nfs_free_server(struct nfs_server *server)
+{
+	nfs_server_remove_lists(server);
+
+	if (server->destroy != NULL)
+		server->destroy(server);
+
+	if (!IS_ERR(server->client_acl))
+		rpc_shutdown_client(server->client_acl);
+	if (!IS_ERR(server->client))
+		rpc_shutdown_client(server->client);
+
+	nfs_put_client(server->nfs_client);
+
+	ida_destroy(&server->lockowner_id);
+	ida_destroy(&server->openowner_id);
+	nfs_free_iostats(server->io_stats);
+	put_cred(server->cred);
+	kfree(server);
+	nfs_release_automount_timer();
+}
+EXPORT_SYMBOL_GPL(nfs_free_server);
+
+/*
+ * Create a version 2 or 3 volume record
+ * - keyed on server and FSID
+ */
+struct nfs_server *nfs_create_server(struct fs_context *fc)
+{
+	struct nfs_fs_context *ctx = nfs_fc2context(fc);
+	struct nfs_server *server;
+	struct nfs_fattr *fattr;
+	int error;
+
+	server = nfs_alloc_server();
+	if (!server)
+		return ERR_PTR(-ENOMEM);
+
+	server->cred = get_cred(fc->cred);
+
+	error = -ENOMEM;
+	fattr = nfs_alloc_fattr();
+	if (fattr == NULL)
+		goto error;
+
+	/* Get a client representation */
+	error = nfs_init_server(server, fc);
+	if (error < 0)
+		goto error;
+
+	/* Probe the root fh to retrieve its FSID */
+	error = nfs_probe_fsinfo(server, ctx->mntfh, fattr);
+	if (error < 0)
+		goto error;
+	if (server->nfs_client->rpc_ops->version == 3) {
+		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
+			server->namelen = NFS3_MAXNAMLEN;
+		if (!(ctx->flags & NFS_MOUNT_NORDIRPLUS))
+			server->caps |= NFS_CAP_READDIRPLUS;
+	} else {
+		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
+			server->namelen = NFS2_MAXNAMLEN;
+	}
+
+	if (!(fattr->valid & NFS_ATTR_FATTR)) {
+		error = ctx->nfs_mod->rpc_ops->getattr(server, ctx->mntfh,
+						       fattr, NULL);
+		if (error < 0) {
+			dprintk("nfs_create_server: getattr error = %d\n", -error);
+			goto error;
+		}
+	}
+	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));
+
+	dprintk("Server FSID: %llx:%llx\n",
+		(unsigned long long) server->fsid.major,
+		(unsigned long long) server->fsid.minor);
+
+	nfs_server_insert_lists(server);
+	server->mount_time = jiffies;
+	nfs_free_fattr(fattr);
+	return server;
+
+error:
+	nfs_free_fattr(fattr);
+	nfs_free_server(server);
+	return ERR_PTR(error);
+}
+EXPORT_SYMBOL_GPL(nfs_create_server);
+
+/*
+ * Clone an NFS2, NFS3 or NFS4 server record
+ */
+struct nfs_server *nfs_clone_server(struct nfs_server *source,
+				    struct nfs_fh *fh,
+				    struct nfs_fattr *fattr,
+				    rpc_authflavor_t flavor)
+{
+	struct nfs_server *server;
+	int error;
+
+	server = nfs_alloc_server();
+	if (!server)
+		return ERR_PTR(-ENOMEM);
+
+	server->cred = get_cred(source->cred);
+
+	/* Copy data from the source */
+	server->nfs_client = source->nfs_client;
+	server->destroy = source->destroy;
+	refcount_inc(&server->nfs_client->cl_count);
+	nfs_server_copy_userdata(server, source);
+
+	server->fsid = fattr->fsid;
+
+	error = nfs_init_server_rpcclient(server,
+			source->client->cl_timeout,
+			flavor);
+	if (error < 0)
+		goto out_free_server;
+
+	/* probe the filesystem info for this server filesystem */
+	error = nfs_probe_server(server, fh);
+	if (error < 0)
+		goto out_free_server;
+
+	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
+		server->namelen = NFS4_MAXNAMLEN;
+
+	error = nfs_start_lockd(server);
+	if (error < 0)
+		goto out_free_server;
+
+	nfs_server_insert_lists(server);
+	server->mount_time = jiffies;
+
+	return server;
+
+out_free_server:
+	nfs_free_server(server);
+	return ERR_PTR(error);
+}
+EXPORT_SYMBOL_GPL(nfs_clone_server);
+
+void nfs_clients_init(struct net *net)
+{
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
+
+	INIT_LIST_HEAD(&nn->nfs_client_list);
+	INIT_LIST_HEAD(&nn->nfs_volume_list);
+#if IS_ENABLED(CONFIG_NFS_V4)
+	idr_init(&nn->cb_ident_idr);
+#endif
+	spin_lock_init(&nn->nfs_client_lock);
+	nn->boot_time = ktime_get_real();
+
+	nfs_netns_sysfs_setup(nn, net);
+}
+
+void nfs_clients_exit(struct net *net)
+{
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
+
+	nfs_netns_sysfs_destroy(nn);
+	nfs_cleanup_cb_ident_idr(net);
+	WARN_ON_ONCE(!list_empty(&nn->nfs_client_list));
+	WARN_ON_ONCE(!list_empty(&nn->nfs_volume_list));
+}
+
+#ifdef CONFIG_PROC_FS
+static void *nfs_server_list_start(struct seq_file *p, loff_t *pos);
+static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos);
+static void nfs_server_list_stop(struct seq_file *p, void *v);
+static int nfs_server_list_show(struct seq_file *m, void *v);
+
+static const struct seq_operations nfs_server_list_ops = {
+	.start	= nfs_server_list_start,
+	.next	= nfs_server_list_next,
+	.stop	= nfs_server_list_stop,
+	.show	= nfs_server_list_show,
+};
+
+static void *nfs_volume_list_start(struct seq_file *p, loff_t *pos);
+static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos);
+static void nfs_volume_list_stop(struct seq_file *p, void *v);
+static int nfs_volume_list_show(struct seq_file *m, void *v);
+
+static const struct seq_operations nfs_volume_list_ops = {
+	.start	= nfs_volume_list_start,
+	.next	= nfs_volume_list_next,
+	.stop	= nfs_volume_list_stop,
+	.show	= nfs_volume_list_show,
+};
+
+/*
+ * set up the iterator to start reading from the server list and return the first item
+ */
+static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
+				__acquires(&nn->nfs_client_lock)
+{
+	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
+
+	/* lock the list against modification */
+	spin_lock(&nn->nfs_client_lock);
+	return seq_list_start_head(&nn->nfs_client_list, *_pos);
+}
+
+/*
+ * move to next server
+ */
+static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
+{
+	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
+
+	return seq_list_next(v, &nn->nfs_client_list, pos);
+}
+
+/*
+ * clean up after reading from the transports list
+ */
+static void nfs_server_list_stop(struct seq_file *p, void *v)
+				__releases(&nn->nfs_client_lock)
+{
+	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
+
+	spin_unlock(&nn->nfs_client_lock);
+}
+
+/*
+ * display a header line followed by a load of call lines
+ */
+static int nfs_server_list_show(struct seq_file *m, void *v)
+{
+	struct nfs_client *clp;
+	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
+
+	/* display header on line 1 */
+	if (v == &nn->nfs_client_list) {
+		seq_puts(m, "NV SERVER   PORT USE HOSTNAME\n");
+		return 0;
+	}
+
+	/* display one transport per line on subsequent lines */
+	clp = list_entry(v, struct nfs_client, cl_share_link);
+
+	/* Check if the client is initialized */
+	if (clp->cl_cons_state != NFS_CS_READY)
+		return 0;
+
+	rcu_read_lock();
+	seq_printf(m, "v%u %s %s %3d %s\n",
+		   clp->rpc_ops->version,
+		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
+		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
+		   refcount_read(&clp->cl_count),
+		   clp->cl_hostname);
+	rcu_read_unlock();
+
+	return 0;
+}
+
+/*
+ * set up the iterator to start reading from the volume list and return the first item
+ */
+static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
+				__acquires(&nn->nfs_client_lock)
+{
+	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
+
+	/* lock the list against modification */
+	spin_lock(&nn->nfs_client_lock);
+	return seq_list_start_head(&nn->nfs_volume_list, *_pos);
+}
+
+/*
+ * move to next volume
+ */
+static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
+{
+	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
+
+	return seq_list_next(v, &nn->nfs_volume_list, pos);
+}
+
+/*
+ * clean up after reading from the transports list
+ */
+static void nfs_volume_list_stop(struct seq_file *p, void *v)
+				__releases(&nn->nfs_client_lock)
+{
+	struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
+
+	spin_unlock(&nn->nfs_client_lock);
+}
+
+/*
+ * display a header line followed by a load of call lines
+ */
+static int nfs_volume_list_show(struct seq_file *m, void *v)
+{
+	struct nfs_server *server;
+	struct nfs_client *clp;
+	char dev[13];	// 8 for 2^24, 1 for ':', 3 for 2^8, 1 for '\0'
+	char fsid[34];	// 2 * 16 for %llx, 1 for ':', 1 for '\0'
+	struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
+
+	/* display header on line 1 */
+	if (v == &nn->nfs_volume_list) {
+		seq_puts(m, "NV SERVER   PORT DEV          FSID"
+			    "                              FSC\n");
+		return 0;
+	}
+	/* display one transport per line on subsequent lines */
+	server = list_entry(v, struct nfs_server, master_link);
+	clp = server->nfs_client;
+
+	snprintf(dev, sizeof(dev), "%u:%u",
+		 MAJOR(server->s_dev), MINOR(server->s_dev));
+
+	snprintf(fsid, sizeof(fsid), "%llx:%llx",
+		 (unsigned long long) server->fsid.major,
+		 (unsigned long long) server->fsid.minor);
+
+	rcu_read_lock();
+	seq_printf(m, "v%u %s %s %-12s %-33s %s\n",
+		   clp->rpc_ops->version,
+		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
+		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
+		   dev,
+		   fsid,
+		   nfs_server_fscache_state(server));
+	rcu_read_unlock();
+
+	return 0;
+}
+
+int nfs_fs_proc_net_init(struct net *net)
+{
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
+	struct proc_dir_entry *p;
+
+	nn->proc_nfsfs = proc_net_mkdir(net, "nfsfs", net->proc_net);
+	if (!nn->proc_nfsfs)
+		goto error_0;
+
+	/* a file of servers with which we're dealing */
+	p = proc_create_net("servers", S_IFREG|S_IRUGO, nn->proc_nfsfs,
+			&nfs_server_list_ops, sizeof(struct seq_net_private));
+	if (!p)
+		goto error_1;
+
+	/* a file of volumes that we have mounted */
+	p = proc_create_net("volumes", S_IFREG|S_IRUGO, nn->proc_nfsfs,
+			&nfs_volume_list_ops, sizeof(struct seq_net_private));
+	if (!p)
+		goto error_1;
+	return 0;
+
+error_1:
+	remove_proc_subtree("nfsfs", net->proc_net);
+error_0:
+	return -ENOMEM;
+}
+
+void nfs_fs_proc_net_exit(struct net *net)
+{
+	remove_proc_subtree("nfsfs", net->proc_net);
+}
+
+/*
+ * initialise the /proc/fs/nfsfs/ directory
+ */
+int __init nfs_fs_proc_init(void)
+{
+	if (!proc_mkdir("fs/nfsfs", NULL))
+		goto error_0;
+
+	/* a file of servers with which we're dealing */
+	if (!proc_symlink("fs/nfsfs/servers", NULL, "../../net/nfsfs/servers"))
+		goto error_1;
+
+	/* a file of volumes that we have mounted */
+	if (!proc_symlink("fs/nfsfs/volumes", NULL, "../../net/nfsfs/volumes"))
+		goto error_1;
+
+	return 0;
+error_1:
+	remove_proc_subtree("fs/nfsfs", NULL);
+error_0:
+	return -ENOMEM;
+}
+
+/*
+ * clean up the /proc/fs/nfsfs/ directory
+ */
+void nfs_fs_proc_exit(void)
+{
+	remove_proc_subtree("fs/nfsfs", NULL);
+}
+
+#endif /* CONFIG_PROC_FS */