<commit_before>/*
 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
 * Written by <NAME> (<EMAIL>)
 */
#include <linux/module.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_idmap.h>
#include <linux/nfs_mount.h>
#include <linux/sunrpc/addr.h>
#include <linux/sunrpc/auth.h>
#include <linux/sunrpc/xprt.h>
#include <linux/sunrpc/bc_xprt.h>
#include <linux/sunrpc/rpc_pipe_fs.h>
#include "internal.h"
#include "callback.h"
#include "delegation.h"
#include "nfs4session.h"
#include "pnfs.h"
#include "netns.h"

#define NFSDBG_FACILITY		NFSDBG_CLIENT

/*
 * Get a unique NFSv4.0 callback identifier which will be used
 * by the V4.0 callback service to lookup the nfs_client struct
 */
static int nfs_get_cb_ident_idr(struct nfs_client *clp, int minorversion)
{
	int ret = 0;
	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);

	if (clp->rpc_ops->version != 4 || minorversion != 0)
		return ret;
	idr_preload(GFP_KERNEL);
	spin_lock(&nn->nfs_client_lock);
	ret = idr_alloc(&nn->cb_ident_idr, clp, 0, 0, GFP_NOWAIT);
	if (ret >= 0)
		clp->cl_cb_ident = ret;
	spin_unlock(&nn->nfs_client_lock);
	idr_preload_end();
	return ret < 0 ? ret : 0;
}

#ifdef CONFIG_NFS_V4_1
/**
 * Per auth flavor data server rpc clients
 */
struct nfs4_ds_server {
	struct list_head	list;   /* ds_clp->cl_ds_clients */
	struct rpc_clnt		*rpc_clnt;
};

/**
 * Common lookup case for DS I/O
 */
static struct nfs4_ds_server *
nfs4_find_ds_client(struct nfs_client *ds_clp, rpc_authflavor_t flavor)
{
	struct nfs4_ds_server *dss;

	rcu_read_lock();
	list_for_each_entry_rcu(dss, &ds_clp->cl_ds_clients, list) {
		if (dss->rpc_clnt->cl_auth->au_flavor != flavor)
			continue;
		goto out;
	}
	dss = NULL;
out:
	rcu_read_unlock();
	return dss;
}

static struct nfs4_ds_server *
nfs4_add_ds_client(struct nfs_client *ds_clp, rpc_authflavor_t flavor,
			   struct nfs4_ds_server *new)
{
	struct nfs4_ds_server *dss;

	spin_lock(&ds_clp->cl_lock);
	list_for_each_entry(dss, &ds_clp->cl_ds_clients, list) {
		if (dss->rpc_clnt->cl_auth->au_flavor != flavor)
			continue;
		goto out;
	}
	if (new)
		list_add_rcu(&new->list, &ds_clp->cl_ds_clients);
	dss = new;
out:
	spin_unlock(&ds_clp->cl_lock); /* need some lock to protect list */
	return dss;
}

static struct nfs4_ds_server *
nfs4_alloc_ds_server(struct nfs_client *ds_clp, rpc_authflavor_t flavor)
{
	struct nfs4_ds_server *dss;

	dss = kmalloc(sizeof(*dss), GFP_NOFS);
	if (dss == NULL)
		return ERR_PTR(-ENOMEM);

	dss->rpc_clnt = rpc_clone_client_set_auth(ds_clp->cl_rpcclient, flavor);
	if (IS_ERR(dss->rpc_clnt)) {
		int err = PTR_ERR(dss->rpc_clnt);
		kfree (dss);
		return ERR_PTR(err);
	}
	INIT_LIST_HEAD(&dss->list);

	return dss;
}

static void
nfs4_free_ds_server(struct nfs4_ds_server *dss)
{
	rpc_release_client(dss->rpc_clnt);
	kfree(dss);
}

/**
* Find or create a DS rpc client with th MDS server rpc client auth flavor
* in the nfs_client cl_ds_clients list.
*/
struct rpc_clnt *
nfs4_find_or_create_ds_client(struct nfs_client *ds_clp, struct inode *inode)
{
	struct nfs4_ds_server *dss, *new;
	rpc_authflavor_t flavor = NFS_SERVER(inode)->client->cl_auth->au_flavor;

	dss = nfs4_find_ds_client(ds_clp, flavor);
	if (dss != NULL)
		goto out;
	new = nfs4_alloc_ds_server(ds_clp, flavor);
	if (IS_ERR(new))
		return ERR_CAST(new);
	dss = nfs4_add_ds_client(ds_clp, flavor, new);
	if (dss != new)
		nfs4_free_ds_server(new);
out:
	return dss->rpc_clnt;
}
EXPORT_SYMBOL_GPL(nfs4_find_or_create_ds_client);

static void
nfs4_shutdown_ds_clients(struct nfs_client *clp)
{
	struct nfs4_ds_server *dss;
	LIST_HEAD(shutdown_list);

	while (!list_empty(&clp->cl_ds_clients)) {
		dss = list_entry(clp->cl_ds_clients.next,
					struct nfs4_ds_server, list);
		list_del(&dss->list);
		rpc_shutdown_client(dss->rpc_clnt);
		kfree (dss);
	}
}

void nfs41_shutdown_client(struct nfs_client *clp)
{
	if (nfs4_has_session(clp)) {
		nfs4_shutdown_ds_clients(clp);
		nfs4_destroy_session(clp->cl_session);
		nfs4_destroy_clientid(clp);
	}

}
#endif	/* CONFIG_NFS_V4_1 */

void nfs40_shutdown_client(struct nfs_client *clp)
{
	if (clp->cl_slot_tbl) {
		nfs4_shutdown_slot_table(clp->cl_slot_tbl);
		kfree(clp->cl_slot_tbl);
	}
}

struct nfs_client *nfs4_alloc_client(const struct nfs_client_initdata *cl_init)
{
	int err;
	struct nfs_client *clp = nfs_alloc_client(cl_init);
	if (IS_ERR(clp))
		return clp;

	err = nfs_get_cb_ident_idr(clp, cl_init->minorversion);
	if (err)
		goto error;

	if (cl_init->minorversion > NFS4_MAX_MINOR_VERSION) {
		err = -EINVAL;
		goto error;
	}

	spin_lock_init(&clp->cl_lock);
	INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state);
	INIT_LIST_HEAD(&clp->cl_ds_clients);
	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
	clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
	clp->cl_minorversion = cl_init->minorversion;
	clp->cl_mvops = nfs_v4_minor_ops[cl_init->minorversion];
	clp->cl_mig_gen = 1;
	return clp;

error:
	nfs_free_client(clp);
	return ERR_PTR(err);
}

/*
 * Destroy the NFS4 callback service
 */
static void nfs4_destroy_callback(struct nfs_client *clp)
{
	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
		nfs_callback_down(clp->cl_mvops->minor_version, clp->cl_net);
}

static void nfs4_shutdown_client(struct nfs_client *clp)
{
	if (__test_and_clear_bit(NFS_CS_RENEWD, &clp->cl_res_state))
		nfs4_kill_renewd(clp);
	clp->cl_mvops->shutdown_client(clp);
	nfs4_destroy_callback(clp);
	if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state))
		nfs_idmap_delete(clp);

	rpc_destroy_wait_queue(&clp->cl_rpcwaitq);
	kfree(clp->cl_serverowner);
	kfree(clp->cl_serverscope);
	kfree(clp->cl_implid);
}

void nfs4_free_client(struct nfs_client *clp)
{
	nfs4_shutdown_client(clp);
	nfs_free_client(clp);
}

/*
 * Initialize the NFS4 callback service
 */
static int nfs4_init_callback(struct nfs_client *clp)
{
	int error;

	if (clp->rpc_ops->version == 4) {
		struct rpc_xprt *xprt;

		xprt = rcu_dereference_raw(clp->cl_rpcclient->cl_xprt);

		if (nfs4_has_session(clp)) {
			error = xprt_setup_backchannel(xprt,
						NFS41_BC_MIN_CALLBACKS);
			if (error < 0)
				return error;
		}

		error = nfs_callback_up(clp->cl_mvops->minor_version, xprt);
		if (error < 0) {
			dprintk("%s: failed to start callback. Error = %d\n",
				__func__, error);
			return error;
		}
		__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
	}
	return 0;
}

/**
 * nfs40_init_client - nfs_client initialization tasks for NFSv4.0
 * @clp - nfs_client to initialize
 *
 * Returns zero on success, or a negative errno if some error occurred.
 */
int nfs40_init_client(struct nfs_client *clp)
{
	struct nfs4_slot_table *tbl;
	int ret;

	tbl = kzalloc(sizeof(*tbl), GFP_NOFS);
	if (tbl == NULL)
		return -ENOMEM;

	ret = nfs4_setup_slot_table(tbl, NFS4_MAX_SLOT_TABLE,
					"NFSv4.0 transport Slot table");
	if (ret) {
		kfree(tbl);
		return ret;
	}

	clp->cl_slot_tbl = tbl;
	return 0;
}

#if defined(CONFIG_NFS_V4_1)

/**
 * nfs41_init_client - nfs_client initialization tasks for NFSv4.1+
 * @clp - nfs_client to initialize
 *
 * Returns zero on success, or a negative errno if some error occurred.
 */
int nfs41_init_client(struct nfs_client *clp)
{
	struct nfs4_session *session = NULL;

	/*
	 * Create the session and mark it expired.
	 * When a SEQUENCE operation encounters the expired session
	 * it will do session recovery to initialize it.
	 */
	session = nfs4_alloc_session(clp);
	if (!session)
		return -ENOMEM;

	clp->cl_session = session;

	/*
	 * The create session reply races with the server back
	 * channel probe. Mark the client NFS_CS_SESSION_INITING
	 * so that the client back channel can find the
	 * nfs_client struct
	 */
	nfs_mark_client_ready(clp, NFS_CS_SESSION_INITING);
	return 0;
}

#endif	/* CONFIG_NFS_V4_1 */

/*
 * Initialize the minor version specific parts of an NFS4 client record
 */
static int nfs4_init_client_minor_version(struct nfs_client *clp)
{
	int ret;

	ret = clp->cl_mvops->init_client(clp);
	if (ret)
		return ret;
	return nfs4_init_callback(clp);
}

/**
 * nfs4_init_client - Initialise an NFS4 client record
 *
 * @clp: nfs_client to initialise
 * @timeparms: timeout parameters for underlying RPC transport
 * @ip_addr: callback IP address in presentation format
 * @authflavor: authentication flavor for underlying RPC transport
 *
 * Returns pointer to an NFS client, or an ERR_PTR value.
 */
struct nfs_client *nfs4_init_client(struct nfs_client *clp,
				    const struct rpc_timeout *timeparms,
				    const char *ip_addr)
{
	char buf[INET6_ADDRSTRLEN + 1];
	struct nfs_client *old;
	int error;

	if (clp->cl_cons_state == NFS_CS_READY) {
		/* the client is initialised already */
		dprintk("<-- nfs4_init_client() = 0 [already %p]\n", clp);
		return clp;
	}

	/* Check NFS protocol revision and initialize RPC op vector */
	clp->rpc_ops = &nfs_v4_clientops;

	if (clp->cl_minorversion != 0)
		__set_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags);
	__set_bit(NFS_CS_DISCRTRY, &clp->cl_flags);
	__set_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags);

	error = nfs_create_rpc_client(clp, timeparms, RPC_AUTH_GSS_KRB5I);
	if (error == -EINVAL)
		error = nfs_create_rpc_client(clp, timeparms, RPC_AUTH_UNIX);
	if (error < 0)
		goto error;

	/* If no clientaddr= option was specified, find a usable cb address */
	if (ip_addr == NULL) {
		struct sockaddr_storage cb_addr;
		struct sockaddr *sap = (struct sockaddr *)&cb_addr;

		error = rpc_localaddr(clp->cl_rpcclient, sap, sizeof(cb_addr));
		if (error < 0)
			goto error;
		error = rpc_ntop(sap, buf, sizeof(buf));
		if (error < 0)
			goto error;
		ip_addr = (const char *)buf;
	}
	strlcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));

	error = nfs_idmap_new(clp);
	if (error < 0) {
		dprintk("%s: failed to create idmapper. Error = %d\n",
			__func__, error);
		goto error;
	}
	__set_bit(NFS_CS_IDMAP, &clp->cl_res_state);

	error = nfs4_init_client_minor_version(clp);
	if (error < 0)
		goto error;

	if (!nfs4_has_session(clp))
		nfs_mark_client_ready(clp, NFS_CS_READY);

	error = nfs4_discover_server_trunking(clp, &old);
	if (error < 0)
		goto error;

	if (clp != old)
		clp->cl_preserve_clid = true;
	nfs_put_client(clp);
	return old;

error:
	nfs_mark_client_ready(clp, error);
	nfs_put_client(clp);
	dprintk("<-- nfs4_init_client() = xerror %d\n", error);
	return ERR_PTR(error);
}

/*
 * SETCLIENTID just did a callback update with the callback ident in
 * "drop," but server trunking discovery claims "drop" and "keep" are
 * actually the same server.  Swap the callback IDs so that "keep"
 * will continue to use the callback ident the server now knows about,
 * and so that "keep"'s original callback ident is destroyed when
 * "drop" is freed.
 */
static void nfs4_swap_callback_idents(struct nfs_client *keep,
				      struct nfs_client *drop)
{
	struct nfs_net *nn = net_generic(keep->cl_net, nfs_net_id);
	unsigned int save = keep->cl_cb_ident;

	if (keep->cl_cb_ident == drop->cl_cb_ident)
		return;

	dprintk("%s: keeping callback ident %u and dropping ident %u\n",
		__func__, keep->cl_cb_ident, drop->cl_cb_ident);

	spin_lock(&nn->nfs_client_lock);

	idr_replace(&nn->cb_ident_idr, keep, drop->cl_cb_ident);
	keep->cl_cb_ident = drop->cl_cb_ident;

	idr_replace(&nn->cb_ident_idr, drop, save);
	drop->cl_cb_ident = save;

	spin_unlock(&nn->nfs_client_lock);
}

/**
 * nfs40_walk_client_list - Find server that recognizes a client ID
 *
 * @new: nfs_client with client ID to test
 * @result: OUT: found nfs_client, or new
 * @cred: credential to use for trunking test
 *
 * Returns zero, a negative errno, or a negative NFS4ERR status.
 * If zero is returned, an nfs_client pointer is planted in "result."
 *
 * NB: nfs40_walk_client_list() relies on the new nfs_client being
 *     the last nfs_client on the list.
 */
int nfs40_walk_client_list(struct nfs_client *new,
			   struct nfs_client **result,
			   struct rpc_cred *cred)
{
	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
	struct nfs_client *pos, *prev = NULL;
	struct nfs4_setclientid_res clid = {
		.clientid	= new->cl_clientid,
		.confirm	= new->cl_confirm,
	};
	int status = -NFS4ERR_STALE_CLIENTID;

	spin_lock(&nn->nfs_client_lock);
	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {
		/* If "pos" isn't marked ready, we can't trust the
		 * remaining fields in "pos" */
		if (pos->cl_cons_state > NFS_CS_READY) {
			atomic_inc(&pos->cl_count);
			spin_unlock(&nn->nfs_client_lock);

			if (prev)
				nfs_put_client(prev);
			prev = pos;

			status = nfs_wait_client_init_complete(pos);
			if (status < 0)
				goto out;
			status = -NFS4ERR_STALE_CLIENTID;
			spin_lock(&nn->nfs_client_lock);
		}
		if (pos->cl_cons_state != NFS_CS_READY)
			continue;

		if (pos->rpc_ops != new->rpc_ops)
			continue;

		if (pos->cl_proto != new->cl_proto)
			continue;

		if (pos->cl_minorversion != new->cl_minorversion)
			continue;

		if (pos->cl_clientid != new->cl_clientid)
			continue;

		atomic_inc(&pos->cl_count);
		spin_unlock(&nn->nfs_client_lock);

		if (prev)
			nfs_put_client(prev);
		prev = pos;

		status = nfs4_proc_setclientid_confirm(pos, &clid, cred);
		switch (status) {
		case -NFS4ERR_STALE_CLIENTID:
			break;
		case 0:
			nfs4_swap_callback_idents(pos, new);

			prev = NULL;
			*result = pos;
			dprintk("NFS: <-- %s using nfs_client = %p ({%d})\n",
				__func__, pos, atomic_read(&pos->cl_count));
		default:
			goto out;
		}

		spin_lock(&nn->nfs_client_lock);
	}
	spin_unlock(&nn->nfs_client_lock);

	/* No match found. The server lost our clientid */
out:
	if (prev)
		nfs_put_client(prev);
	dprintk("NFS: <-- %s status = %d\n", __func__, status);
	return status;
}

#ifdef CONFIG_NFS_V4_1
/*
 * Returns true if the client IDs match
 */
static bool nfs4_match_clientids(struct nfs_client *a, struct nfs_client *b)
{
	if (a->cl_clientid != b->cl_clientid) {
		dprintk("NFS: --> %s client ID %llx does not match %llx\n",
			__func__, a->cl_clientid, b->cl_clientid);
		return false;
	}<commit_msg>NFSv4: Schedule recovery if nfs40_walk_client_list() is interrupted<commit_after>/*
 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
 * Written by <NAME> (<EMAIL>)
 */
#include <linux/module.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_idmap.h>
#include <linux/nfs_mount.h>
#include <linux/sunrpc/addr.h>
#include <linux/sunrpc/auth.h>
#include <linux/sunrpc/xprt.h>
#include <linux/sunrpc/bc_xprt.h>
#include <linux/sunrpc/rpc_pipe_fs.h>
#include "internal.h"
#include "callback.h"
#include "delegation.h"
#include "nfs4session.h"
#include "pnfs.h"
#include "netns.h"

#define NFSDBG_FACILITY		NFSDBG_CLIENT

/*
 * Get a unique NFSv4.0 callback identifier which will be used
 * by the V4.0 callback service to lookup the nfs_client struct
 */
static int nfs_get_cb_ident_idr(struct nfs_client *clp, int minorversion)
{
	int ret = 0;
	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);

	if (clp->rpc_ops->version != 4 || minorversion != 0)
		return ret;
	idr_preload(GFP_KERNEL);
	spin_lock(&nn->nfs_client_lock);
	ret = idr_alloc(&nn->cb_ident_idr, clp, 0, 0, GFP_NOWAIT);
	if (ret >= 0)
		clp->cl_cb_ident = ret;
	spin_unlock(&nn->nfs_client_lock);
	idr_preload_end();
	return ret < 0 ? ret : 0;
}

#ifdef CONFIG_NFS_V4_1
/**
 * Per auth flavor data server rpc clients
 */
struct nfs4_ds_server {
	struct list_head	list;   /* ds_clp->cl_ds_clients */
	struct rpc_clnt		*rpc_clnt;
};

/**
 * Common lookup case for DS I/O
 */
static struct nfs4_ds_server *
nfs4_find_ds_client(struct nfs_client *ds_clp, rpc_authflavor_t flavor)
{
	struct nfs4_ds_server *dss;

	rcu_read_lock();
	list_for_each_entry_rcu(dss, &ds_clp->cl_ds_clients, list) {
		if (dss->rpc_clnt->cl_auth->au_flavor != flavor)
			continue;
		goto out;
	}
	dss = NULL;
out:
	rcu_read_unlock();
	return dss;
}

static struct nfs4_ds_server *
nfs4_add_ds_client(struct nfs_client *ds_clp, rpc_authflavor_t flavor,
			   struct nfs4_ds_server *new)
{
	struct nfs4_ds_server *dss;

	spin_lock(&ds_clp->cl_lock);
	list_for_each_entry(dss, &ds_clp->cl_ds_clients, list) {
		if (dss->rpc_clnt->cl_auth->au_flavor != flavor)
			continue;
		goto out;
	}
	if (new)
		list_add_rcu(&new->list, &ds_clp->cl_ds_clients);
	dss = new;
out:
	spin_unlock(&ds_clp->cl_lock); /* need some lock to protect list */
	return dss;
}

static struct nfs4_ds_server *
nfs4_alloc_ds_server(struct nfs_client *ds_clp, rpc_authflavor_t flavor)
{
	struct nfs4_ds_server *dss;

	dss = kmalloc(sizeof(*dss), GFP_NOFS);
	if (dss == NULL)
		return ERR_PTR(-ENOMEM);

	dss->rpc_clnt = rpc_clone_client_set_auth(ds_clp->cl_rpcclient, flavor);
	if (IS_ERR(dss->rpc_clnt)) {
		int err = PTR_ERR(dss->rpc_clnt);
		kfree (dss);
		return ERR_PTR(err);
	}
	INIT_LIST_HEAD(&dss->list);

	return dss;
}

static void
nfs4_free_ds_server(struct nfs4_ds_server *dss)
{
	rpc_release_client(dss->rpc_clnt);
	kfree(dss);
}

/**
* Find or create a DS rpc client with th MDS server rpc client auth flavor
* in the nfs_client cl_ds_clients list.
*/
struct rpc_clnt *
nfs4_find_or_create_ds_client(struct nfs_client *ds_clp, struct inode *inode)
{
	struct nfs4_ds_server *dss, *new;
	rpc_authflavor_t flavor = NFS_SERVER(inode)->client->cl_auth->au_flavor;

	dss = nfs4_find_ds_client(ds_clp, flavor);
	if (dss != NULL)
		goto out;
	new = nfs4_alloc_ds_server(ds_clp, flavor);
	if (IS_ERR(new))
		return ERR_CAST(new);
	dss = nfs4_add_ds_client(ds_clp, flavor, new);
	if (dss != new)
		nfs4_free_ds_server(new);
out:
	return dss->rpc_clnt;
}
EXPORT_SYMBOL_GPL(nfs4_find_or_create_ds_client);

static void
nfs4_shutdown_ds_clients(struct nfs_client *clp)
{
	struct nfs4_ds_server *dss;
	LIST_HEAD(shutdown_list);

	while (!list_empty(&clp->cl_ds_clients)) {
		dss = list_entry(clp->cl_ds_clients.next,
					struct nfs4_ds_server, list);
		list_del(&dss->list);
		rpc_shutdown_client(dss->rpc_clnt);
		kfree (dss);
	}
}

void nfs41_shutdown_client(struct nfs_client *clp)
{
	if (nfs4_has_session(clp)) {
		nfs4_shutdown_ds_clients(clp);
		nfs4_destroy_session(clp->cl_session);
		nfs4_destroy_clientid(clp);
	}

}
#endif	/* CONFIG_NFS_V4_1 */

void nfs40_shutdown_client(struct nfs_client *clp)
{
	if (clp->cl_slot_tbl) {
		nfs4_shutdown_slot_table(clp->cl_slot_tbl);
		kfree(clp->cl_slot_tbl);
	}
}

struct nfs_client *nfs4_alloc_client(const struct nfs_client_initdata *cl_init)
{
	int err;
	struct nfs_client *clp = nfs_alloc_client(cl_init);
	if (IS_ERR(clp))
		return clp;

	err = nfs_get_cb_ident_idr(clp, cl_init->minorversion);
	if (err)
		goto error;

	if (cl_init->minorversion > NFS4_MAX_MINOR_VERSION) {
		err = -EINVAL;
		goto error;
	}

	spin_lock_init(&clp->cl_lock);
	INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state);
	INIT_LIST_HEAD(&clp->cl_ds_clients);
	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
	clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
	clp->cl_minorversion = cl_init->minorversion;
	clp->cl_mvops = nfs_v4_minor_ops[cl_init->minorversion];
	clp->cl_mig_gen = 1;
	return clp;

error:
	nfs_free_client(clp);
	return ERR_PTR(err);
}

/*
 * Destroy the NFS4 callback service
 */
static void nfs4_destroy_callback(struct nfs_client *clp)
{
	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
		nfs_callback_down(clp->cl_mvops->minor_version, clp->cl_net);
}

static void nfs4_shutdown_client(struct nfs_client *clp)
{
	if (__test_and_clear_bit(NFS_CS_RENEWD, &clp->cl_res_state))
		nfs4_kill_renewd(clp);
	clp->cl_mvops->shutdown_client(clp);
	nfs4_destroy_callback(clp);
	if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state))
		nfs_idmap_delete(clp);

	rpc_destroy_wait_queue(&clp->cl_rpcwaitq);
	kfree(clp->cl_serverowner);
	kfree(clp->cl_serverscope);
	kfree(clp->cl_implid);
}

void nfs4_free_client(struct nfs_client *clp)
{
	nfs4_shutdown_client(clp);
	nfs_free_client(clp);
}

/*
 * Initialize the NFS4 callback service
 */
static int nfs4_init_callback(struct nfs_client *clp)
{
	int error;

	if (clp->rpc_ops->version == 4) {
		struct rpc_xprt *xprt;

		xprt = rcu_dereference_raw(clp->cl_rpcclient->cl_xprt);

		if (nfs4_has_session(clp)) {
			error = xprt_setup_backchannel(xprt,
						NFS41_BC_MIN_CALLBACKS);
			if (error < 0)
				return error;
		}

		error = nfs_callback_up(clp->cl_mvops->minor_version, xprt);
		if (error < 0) {
			dprintk("%s: failed to start callback. Error = %d\n",
				__func__, error);
			return error;
		}
		__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
	}
	return 0;
}

/**
 * nfs40_init_client - nfs_client initialization tasks for NFSv4.0
 * @clp - nfs_client to initialize
 *
 * Returns zero on success, or a negative errno if some error occurred.
 */
int nfs40_init_client(struct nfs_client *clp)
{
	struct nfs4_slot_table *tbl;
	int ret;

	tbl = kzalloc(sizeof(*tbl), GFP_NOFS);
	if (tbl == NULL)
		return -ENOMEM;

	ret = nfs4_setup_slot_table(tbl, NFS4_MAX_SLOT_TABLE,
					"NFSv4.0 transport Slot table");
	if (ret) {
		kfree(tbl);
		return ret;
	}

	clp->cl_slot_tbl = tbl;
	return 0;
}

#if defined(CONFIG_NFS_V4_1)

/**
 * nfs41_init_client - nfs_client initialization tasks for NFSv4.1+
 * @clp - nfs_client to initialize
 *
 * Returns zero on success, or a negative errno if some error occurred.
 */
int nfs41_init_client(struct nfs_client *clp)
{
	struct nfs4_session *session = NULL;

	/*
	 * Create the session and mark it expired.
	 * When a SEQUENCE operation encounters the expired session
	 * it will do session recovery to initialize it.
	 */
	session = nfs4_alloc_session(clp);
	if (!session)
		return -ENOMEM;

	clp->cl_session = session;

	/*
	 * The create session reply races with the server back
	 * channel probe. Mark the client NFS_CS_SESSION_INITING
	 * so that the client back channel can find the
	 * nfs_client struct
	 */
	nfs_mark_client_ready(clp, NFS_CS_SESSION_INITING);
	return 0;
}

#endif	/* CONFIG_NFS_V4_1 */

/*
 * Initialize the minor version specific parts of an NFS4 client record
 */
static int nfs4_init_client_minor_version(struct nfs_client *clp)
{
	int ret;

	ret = clp->cl_mvops->init_client(clp);
	if (ret)
		return ret;
	return nfs4_init_callback(clp);
}

/**
 * nfs4_init_client - Initialise an NFS4 client record
 *
 * @clp: nfs_client to initialise
 * @timeparms: timeout parameters for underlying RPC transport
 * @ip_addr: callback IP address in presentation format
 * @authflavor: authentication flavor for underlying RPC transport
 *
 * Returns pointer to an NFS client, or an ERR_PTR value.
 */
struct nfs_client *nfs4_init_client(struct nfs_client *clp,
				    const struct rpc_timeout *timeparms,
				    const char *ip_addr)
{
	char buf[INET6_ADDRSTRLEN + 1];
	struct nfs_client *old;
	int error;

	if (clp->cl_cons_state == NFS_CS_READY) {
		/* the client is initialised already */
		dprintk("<-- nfs4_init_client() = 0 [already %p]\n", clp);
		return clp;
	}

	/* Check NFS protocol revision and initialize RPC op vector */
	clp->rpc_ops = &nfs_v4_clientops;

	if (clp->cl_minorversion != 0)
		__set_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags);
	__set_bit(NFS_CS_DISCRTRY, &clp->cl_flags);
	__set_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags);

	error = nfs_create_rpc_client(clp, timeparms, RPC_AUTH_GSS_KRB5I);
	if (error == -EINVAL)
		error = nfs_create_rpc_client(clp, timeparms, RPC_AUTH_UNIX);
	if (error < 0)
		goto error;

	/* If no clientaddr= option was specified, find a usable cb address */
	if (ip_addr == NULL) {
		struct sockaddr_storage cb_addr;
		struct sockaddr *sap = (struct sockaddr *)&cb_addr;

		error = rpc_localaddr(clp->cl_rpcclient, sap, sizeof(cb_addr));
		if (error < 0)
			goto error;
		error = rpc_ntop(sap, buf, sizeof(buf));
		if (error < 0)
			goto error;
		ip_addr = (const char *)buf;
	}
	strlcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));

	error = nfs_idmap_new(clp);
	if (error < 0) {
		dprintk("%s: failed to create idmapper. Error = %d\n",
			__func__, error);
		goto error;
	}
	__set_bit(NFS_CS_IDMAP, &clp->cl_res_state);

	error = nfs4_init_client_minor_version(clp);
	if (error < 0)
		goto error;

	if (!nfs4_has_session(clp))
		nfs_mark_client_ready(clp, NFS_CS_READY);

	error = nfs4_discover_server_trunking(clp, &old);
	if (error < 0)
		goto error;

	if (clp != old)
		clp->cl_preserve_clid = true;
	nfs_put_client(clp);
	return old;

error:
	nfs_mark_client_ready(clp, error);
	nfs_put_client(clp);
	dprintk("<-- nfs4_init_client() = xerror %d\n", error);
	return ERR_PTR(error);
}

/*
 * SETCLIENTID just did a callback update with the callback ident in
 * "drop," but server trunking discovery claims "drop" and "keep" are
 * actually the same server.  Swap the callback IDs so that "keep"
 * will continue to use the callback ident the server now knows about,
 * and so that "keep"'s original callback ident is destroyed when
 * "drop" is freed.
 */
static void nfs4_swap_callback_idents(struct nfs_client *keep,
				      struct nfs_client *drop)
{
	struct nfs_net *nn = net_generic(keep->cl_net, nfs_net_id);
	unsigned int save = keep->cl_cb_ident;

	if (keep->cl_cb_ident == drop->cl_cb_ident)
		return;

	dprintk("%s: keeping callback ident %u and dropping ident %u\n",
		__func__, keep->cl_cb_ident, drop->cl_cb_ident);

	spin_lock(&nn->nfs_client_lock);

	idr_replace(&nn->cb_ident_idr, keep, drop->cl_cb_ident);
	keep->cl_cb_ident = drop->cl_cb_ident;

	idr_replace(&nn->cb_ident_idr, drop, save);
	drop->cl_cb_ident = save;

	spin_unlock(&nn->nfs_client_lock);
}

/**
 * nfs40_walk_client_list - Find server that recognizes a client ID
 *
 * @new: nfs_client with client ID to test
 * @result: OUT: found nfs_client, or new
 * @cred: credential to use for trunking test
 *
 * Returns zero, a negative errno, or a negative NFS4ERR status.
 * If zero is returned, an nfs_client pointer is planted in "result."
 *
 * NB: nfs40_walk_client_list() relies on the new nfs_client being
 *     the last nfs_client on the list.
 */
int nfs40_walk_client_list(struct nfs_client *new,
			   struct nfs_client **result,
			   struct rpc_cred *cred)
{
	struct nfs_net *nn = net_generic(new->cl_net, nfs_net_id);
	struct nfs_client *pos, *prev = NULL;
	struct nfs4_setclientid_res clid = {
		.clientid	= new->cl_clientid,
		.confirm	= new->cl_confirm,
	};
	int status = -NFS4ERR_STALE_CLIENTID;

	spin_lock(&nn->nfs_client_lock);
	list_for_each_entry(pos, &nn->nfs_client_list, cl_share_link) {
		/* If "pos" isn't marked ready, we can't trust the
		 * remaining fields in "pos" */
		if (pos->cl_cons_state > NFS_CS_READY) {
			atomic_inc(&pos->cl_count);
			spin_unlock(&nn->nfs_client_lock);

			if (prev)
				nfs_put_client(prev);
			prev = pos;

			status = nfs_wait_client_init_complete(pos);
			if (status < 0)
				goto out;
			status = -NFS4ERR_STALE_CLIENTID;
			spin_lock(&nn->nfs_client_lock);
		}
		if (pos->cl_cons_state != NFS_CS_READY)
			continue;

		if (pos->rpc_ops != new->rpc_ops)
			continue;

		if (pos->cl_proto != new->cl_proto)
			continue;

		if (pos->cl_minorversion != new->cl_minorversion)
			continue;

		if (pos->cl_clientid != new->cl_clientid)
			continue;

		atomic_inc(&pos->cl_count);
		spin_unlock(&nn->nfs_client_lock);

		if (prev)
			nfs_put_client(prev);
		prev = pos;

		status = nfs4_proc_setclientid_confirm(pos, &clid, cred);
		switch (status) {
		case -NFS4ERR_STALE_CLIENTID:
			break;
		case 0:
			nfs4_swap_callback_idents(pos, new);

			prev = NULL;
			*result = pos;
			dprintk("NFS: <-- %s using nfs_client = %p ({%d})\n",
				__func__, pos, atomic_read(&pos->cl_count));
			goto out;
		case -ERESTARTSYS:
		case -ETIMEDOUT:
			/* The callback path may have been inadvertently
			 * changed. Schedule recovery!
			 */
			nfs4_schedule_path_down_recovery(pos);
		default:
			goto out;
		}

		spin_lock(&nn->nfs_client_lock);
	}
	spin_unlock(&nn->nfs_client_lock);

	/* No match found. The server lost our clientid */
out:
	if (prev)
		nfs_put_client(prev);
	dprintk("NFS: <-- %s status = %d\n", __func__, status);
	return status;
}

#ifdef CONFIG_NFS_V4_1
/*
 * Returns true if the client IDs match
 */
static bool nfs4_match_clientids(struct nfs_client *a, struct nfs_client *b)
{
	if (a->cl_clientid != b->cl_clientid) {
		dprintk("NFS: --> %s client ID %llx does not match %llx\n",
			__func__, a->cl_clientid, b->cl_clientid);
		return false;
	}
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