Initial import

1 files changed, 1472 insertions, 0 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
new file mode 100644
index 000000000..892aefff3
--- /dev/null
+++ b/fs/nfs/client.c
@@ -0,0 +1,1472 @@
+/* client.c: NFS client sharing and management code
+ *
+ * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+
+#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/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"
+
+#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;
+	struct rpc_cred *cred;
+	int err = -ENOMEM;
+
+	if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
+		goto error_0;
+
+	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;
+
+	atomic_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_proto = cl_init->proto;
+	clp->cl_net = get_net(cl_init->net);
+
+	cred = rpc_lookup_machine_cred("*");
+	if (!IS_ERR(cred))
+		clp->cl_machine_cred = cred;
+	nfs_fscache_get_client_cookie(clp);
+
+	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)
+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
+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)
+{
+	dprintk("--> nfs_free_client(%u)\n", clp->rpc_ops->version);
+
+	nfs_fscache_release_client_cookie(clp);
+
+	/* -EIO all pending I/O */
+	if (!IS_ERR(clp->cl_rpcclient))
+		rpc_shutdown_client(clp->cl_rpcclient);
+
+	if (clp->cl_machine_cred != NULL)
+		put_rpccred(clp->cl_machine_cred);
+
+	put_net(clp->cl_net);
+	put_nfs_version(clp->cl_nfs_mod);
+	kfree(clp->cl_hostname);
+	kfree(clp->cl_acceptor);
+	kfree(clp);
+
+	dprintk("<-- nfs_free_client()\n");
+}
+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;
+
+	dprintk("--> nfs_put_client({%d})\n", atomic_read(&clp->cl_count));
+	nn = net_generic(clp->cl_net, nfs_net_id);
+
+	if (atomic_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);
+
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+/*
+ * Test if two ip6 socket addresses refer to the same socket by
+ * comparing relevant fields. The padding bytes specifically, are not
+ * compared. sin6_flowinfo is not compared because it only affects QoS
+ * and sin6_scope_id is only compared if the address is "link local"
+ * because "link local" addresses need only be unique to a specific
+ * link. Conversely, ordinary unicast addresses might have different
+ * sin6_scope_id.
+ *
+ * The caller should ensure both socket addresses are AF_INET6.
+ */
+static int nfs_sockaddr_match_ipaddr6(const struct sockaddr *sa1,
+				      const struct sockaddr *sa2)
+{
+	const struct sockaddr_in6 *sin1 = (const struct sockaddr_in6 *)sa1;
+	const struct sockaddr_in6 *sin2 = (const struct sockaddr_in6 *)sa2;
+
+	if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
+		return 0;
+	else if (ipv6_addr_type(&sin1->sin6_addr) & IPV6_ADDR_LINKLOCAL)
+		return sin1->sin6_scope_id == sin2->sin6_scope_id;
+
+	return 1;
+}
+#else	/* !defined(CONFIG_IPV6) && !defined(CONFIG_IPV6_MODULE) */
+static int nfs_sockaddr_match_ipaddr6(const struct sockaddr *sa1,
+				      const struct sockaddr *sa2)
+{
+	return 0;
+}
+#endif
+
+/*
+ * Test if two ip4 socket addresses refer to the same socket, by
+ * comparing relevant fields. The padding bytes specifically, are
+ * not compared.
+ *
+ * The caller should ensure both socket addresses are AF_INET.
+ */
+static int nfs_sockaddr_match_ipaddr4(const struct sockaddr *sa1,
+				      const struct sockaddr *sa2)
+{
+	const struct sockaddr_in *sin1 = (const struct sockaddr_in *)sa1;
+	const struct sockaddr_in *sin2 = (const struct sockaddr_in *)sa2;
+
+	return sin1->sin_addr.s_addr == sin2->sin_addr.s_addr;
+}
+
+static int nfs_sockaddr_cmp_ip6(const struct sockaddr *sa1,
+				const struct sockaddr *sa2)
+{
+	const struct sockaddr_in6 *sin1 = (const struct sockaddr_in6 *)sa1;
+	const struct sockaddr_in6 *sin2 = (const struct sockaddr_in6 *)sa2;
+
+	return nfs_sockaddr_match_ipaddr6(sa1, sa2) &&
+		(sin1->sin6_port == sin2->sin6_port);
+}
+
+static int nfs_sockaddr_cmp_ip4(const struct sockaddr *sa1,
+				const struct sockaddr *sa2)
+{
+	const struct sockaddr_in *sin1 = (const struct sockaddr_in *)sa1;
+	const struct sockaddr_in *sin2 = (const struct sockaddr_in *)sa2;
+
+	return nfs_sockaddr_match_ipaddr4(sa1, sa2) &&
+		(sin1->sin_port == sin2->sin_port);
+}
+
+#if defined(CONFIG_NFS_V4_1)
+/*
+ * Test if two socket addresses represent the same actual socket,
+ * by comparing (only) relevant fields, excluding the port number.
+ */
+int nfs_sockaddr_match_ipaddr(const struct sockaddr *sa1,
+			      const struct sockaddr *sa2)
+{
+	if (sa1->sa_family != sa2->sa_family)
+		return 0;
+
+	switch (sa1->sa_family) {
+	case AF_INET:
+		return nfs_sockaddr_match_ipaddr4(sa1, sa2);
+	case AF_INET6:
+		return nfs_sockaddr_match_ipaddr6(sa1, sa2);
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nfs_sockaddr_match_ipaddr);
+#endif /* CONFIG_NFS_V4_1 */
+
+/*
+ * Test if two socket addresses represent the same actual socket,
+ * by comparing (only) relevant fields, including the port number.
+ */
+static int nfs_sockaddr_cmp(const struct sockaddr *sa1,
+			    const struct sockaddr *sa2)
+{
+	if (sa1->sa_family != sa2->sa_family)
+		return 0;
+
+	switch (sa1->sa_family) {
+	case AF_INET:
+		return nfs_sockaddr_cmp_ip4(sa1, sa2);
+	case AF_INET6:
+		return nfs_sockaddr_cmp_ip6(sa1, sa2);
+	}
+	return 0;
+}
+
+/*
+ * 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 = data->addr;
+	struct nfs_net *nn = net_generic(data->net, nfs_net_id);
+
+	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;
+
+		/* 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 the full socket address */
+		if (!nfs_sockaddr_cmp(sap, clap))
+			continue;
+
+		atomic_inc(&clp->cl_count);
+		return clp;
+	}
+	return NULL;
+}
+
+static bool nfs_client_init_is_complete(const struct nfs_client *clp)
+{
+	return clp->cl_cons_state <= NFS_CS_READY;
+}
+
+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();
+
+	dprintk("<-- %s found nfs_client %p for %s\n",
+		__func__, clp, cl_init->hostname ?: "");
+	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,
+	       const struct rpc_timeout *timeparms,
+	       const char *ip_addr,
+	       rpc_authflavor_t authflavour)
+{
+	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 NULL;
+	}
+
+	dprintk("--> nfs_get_client(%s,v%u)\n",
+		cl_init->hostname, rpc_ops->version);
+
+	/* 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);
+			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);
+			new->cl_flags = cl_init->init_flags;
+			return rpc_ops->init_client(new, timeparms, ip_addr);
+		}
+
+		spin_unlock(&nn->nfs_client_lock);
+
+		new = rpc_ops->alloc_client(cl_init);
+	} while (!IS_ERR(new));
+
+	dprintk("<-- nfs_get_client() Failed to find %s (%ld)\n",
+		cl_init->hostname, PTR_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,
+				    unsigned int timeo, unsigned int retrans)
+{
+	to->to_initval = timeo * HZ / 10;
+	to->to_retries = retrans;
+
+	switch (proto) {
+	case XPRT_TRANSPORT_TCP:
+	case XPRT_TRANSPORT_RDMA:
+		if (to->to_retries == 0)
+			to->to_retries = NFS_DEF_TCP_RETRANS;
+		if (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 (to->to_retries == 0)
+			to->to_retries = NFS_DEF_UDP_RETRANS;
+		if (!to->to_initval)
+			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 rpc_timeout *timeparms,
+			  rpc_authflavor_t flavor)
+{
+	struct rpc_clnt		*clnt = NULL;
+	struct rpc_create_args args = {
+		.net		= clp->cl_net,
+		.protocol	= clp->cl_proto,
+		.address	= (struct sockaddr *)&clp->cl_addr,
+		.addrsize	= clp->cl_addrlen,
+		.timeout	= timeparms,
+		.servername	= clp->cl_hostname,
+		.program	= &nfs_program,
+		.version	= clp->rpc_ops->version,
+		.authflavor	= flavor,
+	};
+
+	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 (!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);
+	}
+
+	clp->cl_rpcclient = clnt;
+	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,
+	};
+
+	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;
+		case XPRT_TRANSPORT_UDP:
+			nlm_init.protocol = IPPROTO_UDP;
+	}
+
+	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_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
+ * @timeparms: timeout parameters for underlying RPC transport
+ * @ip_addr: IP presentation address (not used)
+ *
+ * Returns pointer to an NFS client, or an ERR_PTR value.
+ */
+struct nfs_client *nfs_init_client(struct nfs_client *clp,
+		    const struct rpc_timeout *timeparms,
+		    const char *ip_addr)
+{
+	int error;
+
+	if (clp->cl_cons_state == NFS_CS_READY) {
+		/* the client is already initialised */
+		dprintk("<-- nfs_init_client() = 0 [already %p]\n", clp);
+		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, timeparms, RPC_AUTH_UNIX);
+	if (error < 0)
+		goto error;
+	nfs_mark_client_ready(clp, NFS_CS_READY);
+	return clp;
+
+error:
+	nfs_mark_client_ready(clp, error);
+	nfs_put_client(clp);
+	dprintk("<-- nfs_init_client() = xerror %d\n", error);
+	return ERR_PTR(error);
+}
+EXPORT_SYMBOL_GPL(nfs_init_client);
+
+/*
+ * Create a version 2 or 3 client
+ */
+static int nfs_init_server(struct nfs_server *server,
+			   const struct nfs_parsed_mount_data *data,
+			   struct nfs_subversion *nfs_mod)
+{
+	struct nfs_client_initdata cl_init = {
+		.hostname = data->nfs_server.hostname,
+		.addr = (const struct sockaddr *)&data->nfs_server.address,
+		.addrlen = data->nfs_server.addrlen,
+		.nfs_mod = nfs_mod,
+		.proto = data->nfs_server.protocol,
+		.net = data->net,
+	};
+	struct rpc_timeout timeparms;
+	struct nfs_client *clp;
+	int error;
+
+	dprintk("--> nfs_init_server()\n");
+
+	nfs_init_timeout_values(&timeparms, data->nfs_server.protocol,
+			data->timeo, data->retrans);
+	if (data->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, &timeparms, NULL, RPC_AUTH_UNIX);
+	if (IS_ERR(clp)) {
+		dprintk("<-- nfs_init_server() = error %ld\n", PTR_ERR(clp));
+		return PTR_ERR(clp);
+	}
+
+	server->nfs_client = clp;
+
+	/* Initialise the client representation from the mount data */
+	server->flags = data->flags;
+	server->options = data->options;
+	server->caps |= NFS_CAP_HARDLINKS|NFS_CAP_SYMLINKS|NFS_CAP_FILEID|
+		NFS_CAP_MODE|NFS_CAP_NLINK|NFS_CAP_OWNER|NFS_CAP_OWNER_GROUP|
+		NFS_CAP_ATIME|NFS_CAP_CTIME|NFS_CAP_MTIME|NFS_CAP_CHANGE_ATTR;
+
+	if (data->rsize)
+		server->rsize = nfs_block_size(data->rsize, NULL);
+	if (data->wsize)
+		server->wsize = nfs_block_size(data->wsize, NULL);
+
+	server->acregmin = data->acregmin * HZ;
+	server->acregmax = data->acregmax * HZ;
+	server->acdirmin = data->acdirmin * HZ;
+	server->acdirmax = data->acdirmax * HZ;
+
+	/* Start lockd here, before we might error out */
+	error = nfs_start_lockd(server);
+	if (error < 0)
+		goto error;
+
+	server->port = data->nfs_server.port;
+	server->auth_info = data->auth_info;
+
+	error = nfs_init_server_rpcclient(server, &timeparms,
+					  data->selected_flavor);
+	if (error < 0)
+		goto error;
+
+	/* Preserve the values of mount_server-related mount options */
+	if (data->mount_server.addrlen) {
+		memcpy(&server->mountd_address, &data->mount_server.address,
+			data->mount_server.addrlen);
+		server->mountd_addrlen = data->mount_server.addrlen;
+	}
+	server->mountd_version = data->mount_server.version;
+	server->mountd_port = data->mount_server.port;
+	server->mountd_protocol = data->mount_server.protocol;
+
+	server->namelen  = data->namlen;
+	dprintk("<-- nfs_init_server() = 0 [new %p]\n", clp);
+	return 0;
+
+error:
+	server->nfs_client = NULL;
+	nfs_put_client(clp);
+	dprintk("<-- nfs_init_server() = xerror %d\n", error);
+	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_fh *mntfh,
+				  struct nfs_fsinfo *fsinfo)
+{
+	unsigned long max_rpc_payload;
+
+	/* Work out a lot of parameters */
+	if (server->rsize == 0)
+		server->rsize = nfs_block_size(fsinfo->rtpref, NULL);
+	if (server->wsize == 0)
+		server->wsize = nfs_block_size(fsinfo->wtpref, NULL);
+
+	if (fsinfo->rtmax >= 512 && server->rsize > fsinfo->rtmax)
+		server->rsize = nfs_block_size(fsinfo->rtmax, NULL);
+	if (fsinfo->wtmax >= 512 && server->wsize > fsinfo->wtmax)
+		server->wsize = nfs_block_size(fsinfo->wtmax, NULL);
+
+	max_rpc_payload = nfs_block_size(rpc_max_payload(server->client), 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_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+
+	server->backing_dev_info.name = "nfs";
+	server->backing_dev_info.ra_pages = server->rpages * NFS_MAX_READAHEAD;
+
+	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_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+
+	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
+
+	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
+	if (server->dtsize > PAGE_CACHE_SIZE * NFS_MAX_READDIR_PAGES)
+		server->dtsize = PAGE_CACHE_SIZE * NFS_MAX_READDIR_PAGES;
+	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;
+
+	/* We're airborne Set socket buffersize */
+	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
+}
+
+/*
+ * Probe filesystem information, including the FSID on v2/v3
+ */
+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;
+
+	dprintk("--> nfs_probe_fsinfo()\n");
+
+	if (clp->rpc_ops->set_capabilities != NULL) {
+		error = clp->rpc_ops->set_capabilities(server, mntfh);
+		if (error < 0)
+			goto out_error;
+	}
+
+	fsinfo.fattr = fattr;
+	fsinfo.layouttype = 0;
+	error = clp->rpc_ops->fsinfo(server, mntfh, &fsinfo);
+	if (error < 0)
+		goto out_error;
+
+	nfs_server_set_fsinfo(server, mntfh, &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;
+	}
+
+	dprintk("<-- nfs_probe_fsinfo() = 0\n");
+	return 0;
+
+out_error:
+	dprintk("nfs_probe_fsinfo: error = %d\n", -error);
+	return error;
+}
+EXPORT_SYMBOL_GPL(nfs_probe_fsinfo);
+
+/*
+ * 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;
+}
+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);
+
+	atomic_set(&server->active, 0);
+
+	server->io_stats = nfs_alloc_iostats();
+	if (!server->io_stats) {
+		kfree(server);
+		return NULL;
+	}
+
+	if (bdi_init(&server->backing_dev_info)) {
+		nfs_free_iostats(server->io_stats);
+		kfree(server);
+		return NULL;
+	}
+
+	ida_init(&server->openowner_id);
+	ida_init(&server->lockowner_id);
+	pnfs_init_server(server);
+
+	return server;
+}
+EXPORT_SYMBOL_GPL(nfs_alloc_server);
+
+/*
+ * Free up a server record
+ */
+void nfs_free_server(struct nfs_server *server)
+{
+	dprintk("--> nfs_free_server()\n");
+
+	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);
+	bdi_destroy(&server->backing_dev_info);
+	kfree(server);
+	nfs_release_automount_timer();
+	dprintk("<-- nfs_free_server()\n");
+}
+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 nfs_mount_info *mount_info,
+				     struct nfs_subversion *nfs_mod)
+{
+	struct nfs_server *server;
+	struct nfs_fattr *fattr;
+	int error;
+
+	server = nfs_alloc_server();
+	if (!server)
+		return ERR_PTR(-ENOMEM);
+
+	error = -ENOMEM;
+	fattr = nfs_alloc_fattr();
+	if (fattr == NULL)
+		goto error;
+
+	/* Get a client representation */
+	error = nfs_init_server(server, mount_info->parsed, nfs_mod);
+	if (error < 0)
+		goto error;
+
+	/* Probe the root fh to retrieve its FSID */
+	error = nfs_probe_fsinfo(server, mount_info->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 (!(mount_info->parsed->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 = nfs_mod->rpc_ops->getattr(server, mount_info->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;
+	struct nfs_fattr *fattr_fsinfo;
+	int error;
+
+	dprintk("--> nfs_clone_server(,%llx:%llx,)\n",
+		(unsigned long long) fattr->fsid.major,
+		(unsigned long long) fattr->fsid.minor);
+
+	server = nfs_alloc_server();
+	if (!server)
+		return ERR_PTR(-ENOMEM);
+
+	error = -ENOMEM;
+	fattr_fsinfo = nfs_alloc_fattr();
+	if (fattr_fsinfo == NULL)
+		goto out_free_server;
+
+	/* Copy data from the source */
+	server->nfs_client = source->nfs_client;
+	server->destroy = source->destroy;
+	atomic_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_fsinfo(server, fh, fattr_fsinfo);
+	if (error < 0)
+		goto out_free_server;
+
+	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
+		server->namelen = NFS4_MAXNAMLEN;
+
+	dprintk("Cloned FSID: %llx:%llx\n",
+		(unsigned long long) server->fsid.major,
+		(unsigned long long) server->fsid.minor);
+
+	error = nfs_start_lockd(server);
+	if (error < 0)
+		goto out_free_server;
+
+	nfs_server_insert_lists(server);
+	server->mount_time = jiffies;
+
+	nfs_free_fattr(fattr_fsinfo);
+	dprintk("<-- nfs_clone_server() = %p\n", server);
+	return server;
+
+out_free_server:
+	nfs_free_fattr(fattr_fsinfo);
+	nfs_free_server(server);
+	dprintk("<-- nfs_clone_server() = error %d\n", error);
+	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 = CURRENT_TIME;
+}
+
+#ifdef CONFIG_PROC_FS
+static struct proc_dir_entry *proc_fs_nfs;
+
+static int nfs_server_list_open(struct inode *inode, struct file *file);
+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 const struct file_operations nfs_server_list_fops = {
+	.open		= nfs_server_list_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release_net,
+	.owner		= THIS_MODULE,
+};
+
+static int nfs_volume_list_open(struct inode *inode, struct file *file);
+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,
+};
+
+static const struct file_operations nfs_volume_list_fops = {
+	.open		= nfs_volume_list_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release_net,
+	.owner		= THIS_MODULE,
+};
+
+/*
+ * open "/proc/fs/nfsfs/servers" which provides a summary of servers with which
+ * we're dealing
+ */
+static int nfs_server_list_open(struct inode *inode, struct file *file)
+{
+	return seq_open_net(inode, file, &nfs_server_list_ops,
+			   sizeof(struct seq_net_private));
+}
+
+/*
+ * 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),
+		   atomic_read(&clp->cl_count),
+		   clp->cl_hostname);
+	rcu_read_unlock();
+
+	return 0;
+}
+
+/*
+ * open "/proc/fs/nfsfs/volumes" which provides a summary of extant volumes
+ */
+static int nfs_volume_list_open(struct inode *inode, struct file *file)
+{
+	return seq_open_net(inode, file, &nfs_volume_list_ops,
+			   sizeof(struct seq_net_private));
+}
+
+/*
+ * 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[8], fsid[17];
+	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, 8, "%u:%u",
+		 MAJOR(server->s_dev), MINOR(server->s_dev));
+
+	snprintf(fsid, 17, "%llx:%llx",
+		 (unsigned long long) server->fsid.major,
+		 (unsigned long long) server->fsid.minor);
+
+	rcu_read_lock();
+	seq_printf(m, "v%u %s %s %-7s %-17s %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("servers", S_IFREG|S_IRUGO,
+			nn->proc_nfsfs, &nfs_server_list_fops);
+	if (!p)
+		goto error_1;
+
+	/* a file of volumes that we have mounted */
+	p = proc_create("volumes", S_IFREG|S_IRUGO,
+			nn->proc_nfsfs, &nfs_volume_list_fops);
+	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)
+{
+	struct proc_dir_entry *p;
+
+	proc_fs_nfs = proc_mkdir("fs/nfsfs", NULL);
+	if (!proc_fs_nfs)
+		goto error_0;
+
+	/* a file of servers with which we're dealing */
+	p = proc_symlink("servers", proc_fs_nfs, "../../net/nfsfs/servers");
+	if (!p)
+		goto error_1;
+
+	/* a file of volumes that we have mounted */
+	p = proc_symlink("volumes", proc_fs_nfs, "../../net/nfsfs/volumes");
+	if (!p)
+		goto error_2;
+	return 0;
+
+error_2:
+	remove_proc_entry("servers", proc_fs_nfs);
+error_1:
+	remove_proc_entry("fs/nfsfs", NULL);
+error_0:
+	return -ENOMEM;
+}
+
+/*
+ * clean up the /proc/fs/nfsfs/ directory
+ */
+void nfs_fs_proc_exit(void)
+{
+	remove_proc_entry("volumes", proc_fs_nfs);
+	remove_proc_entry("servers", proc_fs_nfs);
+	remove_proc_entry("fs/nfsfs", NULL);
+}
+
+#endif /* CONFIG_PROC_FS */