/* 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/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"

  
  #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)

  {

  	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);

  }

  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 (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);

  /*

   * 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);

  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) {
  			atomic_inc(&clp->cl_count);
  			spin_unlock(&nn->nfs_client_lock);
  			nfs_wait_client_init_complete(clp);
  			nfs_put_client(clp);
  			spin_lock(&nn->nfs_client_lock);
  			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 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;

  
  		atomic_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 NULL;
  	}

  	/* 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, 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_retries == 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,

  		.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,
  	};

  	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
  ",

  				__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,

  		.nlmclnt_ops 	= clp->cl_nfs_mod->rpc_ops->nlmclnt_ops,

  	};

  	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!
  ", __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

   * @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 nfs_parsed_mount_data *data,
  			   struct nfs_subversion *nfs_mod)

  {

  	struct rpc_timeout timeparms;

  	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,

  		.timeparms = &timeparms,

  	};

  	struct nfs_client *clp;

  	int error;

  	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);

  	if (IS_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;

  
  	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;

  	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)

  {
  	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_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 > PAGE_SIZE * NFS_MAX_READDIR_PAGES)
  		server->dtsize = PAGE_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;

  	server->clone_blksize = fsinfo->clone_blksize;

  	/* 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;

  	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;
  	}

  	return 0;

  }

  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;

  	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);

  	atomic_set(&server->active, 0);

  	server->io_stats = nfs_alloc_iostats();
  	if (!server->io_stats) {
  		kfree(server);
  		return NULL;
  	}

  	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);
  	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 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
  ", -error);
  			goto error;
  		}
  	}

  	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));

  	dprintk("Server FSID: %llx:%llx
  ",
  		(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;

  	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;

  	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);

  	return server;
  
  out_free_server:

  	nfs_free_fattr(fattr_fsinfo);

  	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();

  }

  #ifdef CONFIG_PROC_FS

  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,

  };
  
  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,

  };
  
  /*
   * 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
  ");
  		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
  ",

  		   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[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
  ");

  		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
  ",

  		   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)
  {

  	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 */