[mirror_ubuntu-kernels.git] / fs / nfs / nfs4session.c

/*
 * fs/nfs/nfs4session.c
 *
 * Copyright (c) 2012 Trond Myklebust <Trond.Myklebust@netapp.com>
 *
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/bc_xprt.h>
#include <linux/nfs.h>
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/module.h>

#include "nfs4_fs.h"
#include "internal.h"
#include "nfs4session.h"
#include "callback.h"

#define NFSDBG_FACILITY		NFSDBG_STATE

static void nfs4_init_slot_table(struct nfs4_slot_table *tbl, const char *queue)
{
	tbl->highest_used_slotid = NFS4_NO_SLOT;
	spin_lock_init(&tbl->slot_tbl_lock);
	rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, queue);
	init_waitqueue_head(&tbl->slot_waitq);
	init_completion(&tbl->complete);
}

/*
 * nfs4_shrink_slot_table - free retired slots from the slot table
 */
static void nfs4_shrink_slot_table(struct nfs4_slot_table  *tbl, u32 newsize)
{
	struct nfs4_slot **p;
	if (newsize >= tbl->max_slots)
		return;

	p = &tbl->slots;
	while (newsize--)
		p = &(*p)->next;
	while (*p) {
		struct nfs4_slot *slot = *p;

		*p = slot->next;
		kfree(slot);
		tbl->max_slots--;
	}
}

/**
 * nfs4_slot_tbl_drain_complete - wake waiters when drain is complete
 * @tbl: controlling slot table
 *
 */
void nfs4_slot_tbl_drain_complete(struct nfs4_slot_table *tbl)
{
	if (nfs4_slot_tbl_draining(tbl))
		complete(&tbl->complete);
}

/*
 * nfs4_free_slot - free a slot and efficiently update slot table.
 *
 * freeing a slot is trivially done by clearing its respective bit
 * in the bitmap.
 * If the freed slotid equals highest_used_slotid we want to update it
 * so that the server would be able to size down the slot table if needed,
 * otherwise we know that the highest_used_slotid is still in use.
 * When updating highest_used_slotid there may be "holes" in the bitmap
 * so we need to scan down from highest_used_slotid to 0 looking for the now
 * highest slotid in use.
 * If none found, highest_used_slotid is set to NFS4_NO_SLOT.
 *
 * Must be called while holding tbl->slot_tbl_lock
 */
void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
{
	u32 slotid = slot->slot_nr;

	/* clear used bit in bitmap */
	__clear_bit(slotid, tbl->used_slots);

	/* update highest_used_slotid when it is freed */
	if (slotid == tbl->highest_used_slotid) {
		u32 new_max = find_last_bit(tbl->used_slots, slotid);
		if (new_max < slotid)
			tbl->highest_used_slotid = new_max;
		else {
			tbl->highest_used_slotid = NFS4_NO_SLOT;
			nfs4_slot_tbl_drain_complete(tbl);
		}
	}
	dprintk("%s: slotid %u highest_used_slotid %u\n", __func__,
		slotid, tbl->highest_used_slotid);
}

static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table  *tbl,
		u32 slotid, u32 seq_init, gfp_t gfp_mask)
{
	struct nfs4_slot *slot;

	slot = kzalloc(sizeof(*slot), gfp_mask);
	if (slot) {
		slot->table = tbl;
		slot->slot_nr = slotid;
		slot->seq_nr = seq_init;
		slot->seq_nr_highest_sent = seq_init;
		slot->seq_nr_last_acked = seq_init - 1;
	}
	return slot;
}

static struct nfs4_slot *nfs4_find_or_create_slot(struct nfs4_slot_table  *tbl,
		u32 slotid, u32 seq_init, gfp_t gfp_mask)
{
	struct nfs4_slot **p, *slot;

	p = &tbl->slots;
	for (;;) {
		if (*p == NULL) {
			*p = nfs4_new_slot(tbl, tbl->max_slots,
					seq_init, gfp_mask);
			if (*p == NULL)
				break;
			tbl->max_slots++;
		}
		slot = *p;
		if (slot->slot_nr == slotid)
			return slot;
		p = &slot->next;
	}
	return ERR_PTR(-ENOMEM);
}

static void nfs4_lock_slot(struct nfs4_slot_table *tbl,
		struct nfs4_slot *slot)
{
	u32 slotid = slot->slot_nr;

	__set_bit(slotid, tbl->used_slots);
	if (slotid > tbl->highest_used_slotid ||
	    tbl->highest_used_slotid == NFS4_NO_SLOT)
		tbl->highest_used_slotid = slotid;
	slot->generation = tbl->generation;
}

/*
 * nfs4_try_to_lock_slot - Given a slot try to allocate it
 *
 * Note: must be called with the slot_tbl_lock held.
 */
bool nfs4_try_to_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
{
	if (nfs4_test_locked_slot(tbl, slot->slot_nr))
		return false;
	nfs4_lock_slot(tbl, slot);
	return true;
}

/*
 * nfs4_lookup_slot - Find a slot but don't allocate it
 *
 * Note: must be called with the slot_tbl_lock held.
 */
struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid)
{
	if (slotid <= tbl->max_slotid)
		return nfs4_find_or_create_slot(tbl, slotid, 0, GFP_NOWAIT);
	return ERR_PTR(-E2BIG);
}

static int nfs4_slot_get_seqid(struct nfs4_slot_table  *tbl, u32 slotid,
		u32 *seq_nr)
	__must_hold(&tbl->slot_tbl_lock)
{
	struct nfs4_slot *slot;
	int ret;

	slot = nfs4_lookup_slot(tbl, slotid);
	ret = PTR_ERR_OR_ZERO(slot);
	if (!ret)
		*seq_nr = slot->seq_nr;

	return ret;
}

/*
 * nfs4_slot_seqid_in_use - test if a slot sequence id is still in use
 *
 * Given a slot table, slot id and sequence number, determine if the
 * RPC call in question is still in flight. This function is mainly
 * intended for use by the callback channel.
 */
static bool nfs4_slot_seqid_in_use(struct nfs4_slot_table *tbl,
		u32 slotid, u32 seq_nr)
{
	u32 cur_seq = 0;
	bool ret = false;

	spin_lock(&tbl->slot_tbl_lock);
	if (nfs4_slot_get_seqid(tbl, slotid, &cur_seq) == 0 &&
	    cur_seq == seq_nr && test_bit(slotid, tbl->used_slots))
		ret = true;
	spin_unlock(&tbl->slot_tbl_lock);
	return ret;
}

/*
 * nfs4_slot_wait_on_seqid - wait until a slot sequence id is complete
 *
 * Given a slot table, slot id and sequence number, wait until the
 * corresponding RPC call completes. This function is mainly
 * intended for use by the callback channel.
 */
int nfs4_slot_wait_on_seqid(struct nfs4_slot_table *tbl,
		u32 slotid, u32 seq_nr,
		unsigned long timeout)
{
	if (wait_event_timeout(tbl->slot_waitq,
			!nfs4_slot_seqid_in_use(tbl, slotid, seq_nr),
			timeout) == 0)
		return -ETIMEDOUT;
	return 0;
}

/*
 * nfs4_alloc_slot - efficiently look for a free slot
 *
 * nfs4_alloc_slot looks for an unset bit in the used_slots bitmap.
 * If found, we mark the slot as used, update the highest_used_slotid,
 * and respectively set up the sequence operation args.
 *
 * Note: must be called with under the slot_tbl_lock.
 */
struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl)
{
	struct nfs4_slot *ret = ERR_PTR(-EBUSY);
	u32 slotid;

	dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n",
		__func__, tbl->used_slots[0], tbl->highest_used_slotid,
		tbl->max_slotid + 1);
	slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1);
	if (slotid <= tbl->max_slotid) {
		ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
		if (!IS_ERR(ret))
			nfs4_lock_slot(tbl, ret);
	}
	dprintk("<-- %s used_slots=%04lx highest_used=%u slotid=%u\n",
		__func__, tbl->used_slots[0], tbl->highest_used_slotid,
		!IS_ERR(ret) ? ret->slot_nr : NFS4_NO_SLOT);
	return ret;
}

static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl,
		 u32 max_reqs, u32 ivalue)
{
	if (max_reqs <= tbl->max_slots)
		return 0;
	if (!IS_ERR(nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS)))
		return 0;
	return -ENOMEM;
}

static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
		u32 server_highest_slotid,
		u32 ivalue)
{
	struct nfs4_slot **p;

	nfs4_shrink_slot_table(tbl, server_highest_slotid + 1);
	p = &tbl->slots;
	while (*p) {
		(*p)->seq_nr = ivalue;
		(*p)->seq_nr_highest_sent = ivalue;
		(*p)->seq_nr_last_acked = ivalue - 1;
		p = &(*p)->next;
	}
	tbl->highest_used_slotid = NFS4_NO_SLOT;
	tbl->target_highest_slotid = server_highest_slotid;
	tbl->server_highest_slotid = server_highest_slotid;
	tbl->d_target_highest_slotid = 0;
	tbl->d2_target_highest_slotid = 0;
	tbl->max_slotid = server_highest_slotid;
}

/*
 * (re)Initialise a slot table
 */
static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl,
		u32 max_reqs, u32 ivalue)
{
	int ret;

	dprintk("--> %s: max_reqs=%u, tbl->max_slots %u\n", __func__,
		max_reqs, tbl->max_slots);

	if (max_reqs > NFS4_MAX_SLOT_TABLE)
		max_reqs = NFS4_MAX_SLOT_TABLE;

	ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue);
	if (ret)
		goto out;

	spin_lock(&tbl->slot_tbl_lock);
	nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue);
	spin_unlock(&tbl->slot_tbl_lock);

	dprintk("%s: tbl=%p slots=%p max_slots=%u\n", __func__,
		tbl, tbl->slots, tbl->max_slots);
out:
	dprintk("<-- %s: return %d\n", __func__, ret);
	return ret;
}

/*
 * nfs4_release_slot_table - release all slot table entries
 */
static void nfs4_release_slot_table(struct nfs4_slot_table *tbl)
{
	nfs4_shrink_slot_table(tbl, 0);
}

/**
 * nfs4_shutdown_slot_table - release resources attached to a slot table
 * @tbl: slot table to shut down
 *
 */
void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl)
{
	nfs4_release_slot_table(tbl);
	rpc_destroy_wait_queue(&tbl->slot_tbl_waitq);
}

/**
 * nfs4_setup_slot_table - prepare a stand-alone slot table for use
 * @tbl: slot table to set up
 * @max_reqs: maximum number of requests allowed
 * @queue: name to give RPC wait queue
 *
 * Returns zero on success, or a negative errno.
 */
int nfs4_setup_slot_table(struct nfs4_slot_table *tbl, unsigned int max_reqs,
		const char *queue)
{
	nfs4_init_slot_table(tbl, queue);
	return nfs4_realloc_slot_table(tbl, max_reqs, 0);
}

static bool nfs41_assign_slot(struct rpc_task *task, void *pslot)
{
	struct nfs4_sequence_args *args = task->tk_msg.rpc_argp;
	struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;
	struct nfs4_slot *slot = pslot;
	struct nfs4_slot_table *tbl = slot->table;

	if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged)
		return false;
	slot->generation = tbl->generation;
	args->sa_slot = slot;
	res->sr_timestamp = jiffies;
	res->sr_slot = slot;
	res->sr_status_flags = 0;
	res->sr_status = 1;
	return true;
}

static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
		struct nfs4_slot *slot)
{
	if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot))
		return true;
	return false;
}

bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
		struct nfs4_slot *slot)
{
	if (slot->slot_nr > tbl->max_slotid)
		return false;
	return __nfs41_wake_and_assign_slot(tbl, slot);
}

static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl)
{
	struct nfs4_slot *slot = nfs4_alloc_slot(tbl);
	if (!IS_ERR(slot)) {
		bool ret = __nfs41_wake_and_assign_slot(tbl, slot);
		if (ret)
			return ret;
		nfs4_free_slot(tbl, slot);
	}
	return false;
}

void nfs41_wake_slot_table(struct nfs4_slot_table *tbl)
{
	for (;;) {
		if (!nfs41_try_wake_next_slot_table_entry(tbl))
			break;
	}
}

#if defined(CONFIG_NFS_V4_1)

static void nfs41_set_max_slotid_locked(struct nfs4_slot_table *tbl,
		u32 target_highest_slotid)
{
	u32 max_slotid;

	max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, target_highest_slotid);
	if (max_slotid > tbl->server_highest_slotid)
		max_slotid = tbl->server_highest_slotid;
	if (max_slotid > tbl->target_highest_slotid)
		max_slotid = tbl->target_highest_slotid;
	tbl->max_slotid = max_slotid;
	nfs41_wake_slot_table(tbl);
}

/* Update the client's idea of target_highest_slotid */
static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,
		u32 target_highest_slotid)
{
	if (tbl->target_highest_slotid == target_highest_slotid)
		return;
	tbl->target_highest_slotid = target_highest_slotid;
	tbl->generation++;
}

void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
		u32 target_highest_slotid)
{
	spin_lock(&tbl->slot_tbl_lock);
	nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
	tbl->d_target_highest_slotid = 0;
	tbl->d2_target_highest_slotid = 0;
	nfs41_set_max_slotid_locked(tbl, target_highest_slotid);
	spin_unlock(&tbl->slot_tbl_lock);
}

static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl,
		u32 highest_slotid)
{
	if (tbl->server_highest_slotid == highest_slotid)
		return;
	if (tbl->highest_used_slotid > highest_slotid)
		return;
	/* Deallocate slots */
	nfs4_shrink_slot_table(tbl, highest_slotid + 1);
	tbl->server_highest_slotid = highest_slotid;
}

static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2)
{
	s1 -= s2;
	if (s1 == 0)
		return 0;
	if (s1 < 0)
		return (s1 - 1) >> 1;
	return (s1 + 1) >> 1;
}

static int nfs41_sign_s32(s32 s1)
{
	if (s1 > 0)
		return 1;
	if (s1 < 0)
		return -1;
	return 0;
}

static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2)
{
	if (!s1 || !s2)
		return true;
	return nfs41_sign_s32(s1) == nfs41_sign_s32(s2);
}

/* Try to eliminate outliers by checking for sharp changes in the
 * derivatives and second derivatives
 */
static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl,
		u32 new_target)
{
	s32 d_target, d2_target;
	bool ret = true;

	d_target = nfs41_derivative_target_slotid(new_target,
			tbl->target_highest_slotid);
	d2_target = nfs41_derivative_target_slotid(d_target,
			tbl->d_target_highest_slotid);
	/* Is first derivative same sign? */
	if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid))
		ret = false;
	/* Is second derivative same sign? */
	if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid))
		ret = false;
	tbl->d_target_highest_slotid = d_target;
	tbl->d2_target_highest_slotid = d2_target;
	return ret;
}

void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
		struct nfs4_slot *slot,
		struct nfs4_sequence_res *res)
{
	spin_lock(&tbl->slot_tbl_lock);
	if (!nfs41_is_outlier_target_slotid(tbl, res->sr_target_highest_slotid))
		nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
	if (tbl->generation == slot->generation)
		nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
	nfs41_set_max_slotid_locked(tbl, res->sr_target_highest_slotid);
	spin_unlock(&tbl->slot_tbl_lock);
}

static void nfs4_release_session_slot_tables(struct nfs4_session *session)
{
	nfs4_release_slot_table(&session->fc_slot_table);
	nfs4_release_slot_table(&session->bc_slot_table);
}

/*
 * Initialize or reset the forechannel and backchannel tables
 */
int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
{
	struct nfs4_slot_table *tbl;
	int status;

	dprintk("--> %s\n", __func__);
	/* Fore channel */
	tbl = &ses->fc_slot_table;
	tbl->session = ses;
	status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
	if (status || !(ses->flags & SESSION4_BACK_CHAN)) /* -ENOMEM */
		return status;
	/* Back channel */
	tbl = &ses->bc_slot_table;
	tbl->session = ses;
	status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
	if (status && tbl->slots == NULL)
		/* Fore and back channel share a connection so get
		 * both slot tables or neither */
		nfs4_release_session_slot_tables(ses);
	return status;
}

struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
{
	struct nfs4_session *session;

	session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
	if (!session)
		return NULL;

	nfs4_init_slot_table(&session->fc_slot_table, "ForeChannel Slot table");
	nfs4_init_slot_table(&session->bc_slot_table, "BackChannel Slot table");
	session->session_state = 1<<NFS4_SESSION_INITING;

	session->clp = clp;
	return session;
}

static void nfs4_destroy_session_slot_tables(struct nfs4_session *session)
{
	nfs4_shutdown_slot_table(&session->fc_slot_table);
	nfs4_shutdown_slot_table(&session->bc_slot_table);
}

void nfs4_destroy_session(struct nfs4_session *session)
{
	struct rpc_xprt *xprt;
	const struct cred *cred;

	cred = nfs4_get_clid_cred(session->clp);
	nfs4_proc_destroy_session(session, cred);
	put_cred(cred);

	rcu_read_lock();
	xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt);
	rcu_read_unlock();
	dprintk("%s Destroy backchannel for xprt %p\n",
		__func__, xprt);
	xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
	nfs4_destroy_session_slot_tables(session);
	kfree(session);
}

/*
 * With sessions, the client is not marked ready until after a
 * successful EXCHANGE_ID and CREATE_SESSION.
 *
 * Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate
 * other versions of NFS can be tried.
 */
static int nfs41_check_session_ready(struct nfs_client *clp)
{
	int ret;
	
	if (clp->cl_cons_state == NFS_CS_SESSION_INITING) {
		ret = nfs4_client_recover_expired_lease(clp);
		if (ret)
			return ret;
	}
	if (clp->cl_cons_state < NFS_CS_READY)
		return -EPROTONOSUPPORT;
	smp_rmb();
	return 0;
}

int nfs4_init_session(struct nfs_client *clp)
{
	if (!nfs4_has_session(clp))
		return 0;

	clear_bit(NFS4_SESSION_INITING, &clp->cl_session->session_state);
	return nfs41_check_session_ready(clp);
}

int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time)
{
	struct nfs4_session *session = clp->cl_session;
	int ret;

	spin_lock(&clp->cl_lock);
	if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
		/*
		 * Do not set NFS_CS_CHECK_LEASE_TIME instead set the
		 * DS lease to be equal to the MDS lease.
		 */
		clp->cl_lease_time = lease_time;
		clp->cl_last_renewal = jiffies;
	}
	spin_unlock(&clp->cl_lock);

	ret = nfs41_check_session_ready(clp);
	if (ret)
		return ret;
	/* Test for the DS role */
	if (!is_ds_client(clp))
		return -ENODEV;
	return 0;
}
EXPORT_SYMBOL_GPL(nfs4_init_ds_session);

#endif	/* defined(CONFIG_NFS_V4_1) */
Commit	Line	Data
73e39aaa TM	1	/*
	2	* fs/nfs/nfs4session.c
	3	*
	4	* Copyright (c) 2012 Trond Myklebust <Trond.Myklebust@netapp.com>
	5	*
	6	*/
	7	#include <linux/kernel.h>
	8	#include <linux/errno.h>
	9	#include <linux/string.h>
	10	#include <linux/printk.h>
	11	#include <linux/slab.h>
	12	#include <linux/sunrpc/sched.h>
	13	#include <linux/sunrpc/bc_xprt.h>
	14	#include <linux/nfs.h>
	15	#include <linux/nfs4.h>
	16	#include <linux/nfs_fs.h>
	17	#include <linux/module.h>
	18
	19	#include "nfs4_fs.h"
	20	#include "internal.h"
	21	#include "nfs4session.h"
	22	#include "callback.h"
	23
	24	#define NFSDBG_FACILITY NFSDBG_STATE
	25
744aa525 CL	26	static void nfs4_init_slot_table(struct nfs4_slot_table tbl, const char queue)
	27	{
	28	tbl->highest_used_slotid = NFS4_NO_SLOT;
	29	spin_lock_init(&tbl->slot_tbl_lock);
	30	rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, queue);
045d2a6d	31	init_waitqueue_head(&tbl->slot_waitq);
744aa525 CL	32	init_completion(&tbl->complete);
	33	}
	34
73e39aaa TM	35	/*
	36	* nfs4_shrink_slot_table - free retired slots from the slot table
	37	*/
	38	static void nfs4_shrink_slot_table(struct nfs4_slot_table *tbl, u32 newsize)
	39	{
	40	struct nfs4_slot **p;
	41	if (newsize >= tbl->max_slots)
	42	return;
	43
	44	p = &tbl->slots;
	45	while (newsize--)
	46	p = &(*p)->next;
	47	while (*p) {
	48	struct nfs4_slot slot = p;
	49
	50	*p = slot->next;
	51	kfree(slot);
	52	tbl->max_slots--;
	53	}
	54	}
	55
9d33059c CL	56	/**
9d33059c CL	57	* nfs4_slot_tbl_drain_complete - wake waiters when drain is complete
302fad7b	58	* @tbl: controlling slot table
9d33059c CL	59	*
	60	*/
	61	void nfs4_slot_tbl_drain_complete(struct nfs4_slot_table *tbl)
	62	{
	63	if (nfs4_slot_tbl_draining(tbl))
	64	complete(&tbl->complete);
	65	}
	66
73e39aaa TM	67	/*
	68	* nfs4_free_slot - free a slot and efficiently update slot table.
	69	*
	70	* freeing a slot is trivially done by clearing its respective bit
	71	* in the bitmap.
	72	* If the freed slotid equals highest_used_slotid we want to update it
	73	* so that the server would be able to size down the slot table if needed,
	74	* otherwise we know that the highest_used_slotid is still in use.
	75	* When updating highest_used_slotid there may be "holes" in the bitmap
	76	* so we need to scan down from highest_used_slotid to 0 looking for the now
	77	* highest slotid in use.
	78	* If none found, highest_used_slotid is set to NFS4_NO_SLOT.
	79	*
	80	* Must be called while holding tbl->slot_tbl_lock
	81	*/
	82	void nfs4_free_slot(struct nfs4_slot_table tbl, struct nfs4_slot slot)
	83	{
	84	u32 slotid = slot->slot_nr;
	85
	86	/* clear used bit in bitmap */
	87	__clear_bit(slotid, tbl->used_slots);
	88
	89	/* update highest_used_slotid when it is freed */
	90	if (slotid == tbl->highest_used_slotid) {
	91	u32 new_max = find_last_bit(tbl->used_slots, slotid);
	92	if (new_max < slotid)
	93	tbl->highest_used_slotid = new_max;
	94	else {
	95	tbl->highest_used_slotid = NFS4_NO_SLOT;
774d5f14	96	nfs4_slot_tbl_drain_complete(tbl);
73e39aaa TM	97	}
73e39aaa TM	98	}
e8d92382	99	dprintk("%s: slotid %u highest_used_slotid %u\n", __func__,
73e39aaa TM	100	slotid, tbl->highest_used_slotid);
	101	}
	102
	103	static struct nfs4_slot nfs4_new_slot(struct nfs4_slot_table tbl,
	104	u32 slotid, u32 seq_init, gfp_t gfp_mask)
	105	{
	106	struct nfs4_slot *slot;
	107
	108	slot = kzalloc(sizeof(*slot), gfp_mask);
	109	if (slot) {
	110	slot->table = tbl;
	111	slot->slot_nr = slotid;
	112	slot->seq_nr = seq_init;
3453d570 TM	113	slot->seq_nr_highest_sent = seq_init;
3453d570 TM	114	slot->seq_nr_last_acked = seq_init - 1;
73e39aaa TM	115	}
	116	return slot;
	117	}
	118
	119	static struct nfs4_slot nfs4_find_or_create_slot(struct nfs4_slot_table tbl,
	120	u32 slotid, u32 seq_init, gfp_t gfp_mask)
	121	{
	122	struct nfs4_slot *p, slot;
	123
	124	p = &tbl->slots;
	125	for (;;) {
	126	if (*p == NULL) {
	127	*p = nfs4_new_slot(tbl, tbl->max_slots,
	128	seq_init, gfp_mask);
	129	if (*p == NULL)
	130	break;
	131	tbl->max_slots++;
	132	}
	133	slot = *p;
	134	if (slot->slot_nr == slotid)
	135	return slot;
	136	p = &slot->next;
	137	}
	138	return ERR_PTR(-ENOMEM);
	139	}
	140
810d82e6 TM	141	static void nfs4_lock_slot(struct nfs4_slot_table *tbl,
	142	struct nfs4_slot *slot)
	143	{
	144	u32 slotid = slot->slot_nr;
	145
	146	__set_bit(slotid, tbl->used_slots);
	147	if (slotid > tbl->highest_used_slotid \|\|
	148	tbl->highest_used_slotid == NFS4_NO_SLOT)
	149	tbl->highest_used_slotid = slotid;
	150	slot->generation = tbl->generation;
	151	}
	152
	153	/*
	154	* nfs4_try_to_lock_slot - Given a slot try to allocate it
	155	*
	156	* Note: must be called with the slot_tbl_lock held.
	157	*/
	158	bool nfs4_try_to_lock_slot(struct nfs4_slot_table tbl, struct nfs4_slot slot)
	159	{
	160	if (nfs4_test_locked_slot(tbl, slot->slot_nr))
	161	return false;
	162	nfs4_lock_slot(tbl, slot);
	163	return true;
	164	}
	165
	166	/*
	167	* nfs4_lookup_slot - Find a slot but don't allocate it
	168	*
	169	* Note: must be called with the slot_tbl_lock held.
	170	*/
	171	struct nfs4_slot nfs4_lookup_slot(struct nfs4_slot_table tbl, u32 slotid)
	172	{
	173	if (slotid <= tbl->max_slotid)
9a837856	174	return nfs4_find_or_create_slot(tbl, slotid, 0, GFP_NOWAIT);
810d82e6 TM	175	return ERR_PTR(-E2BIG);
	176	}
	177
e09c978a TM	178	static int nfs4_slot_get_seqid(struct nfs4_slot_table *tbl, u32 slotid,
	179	u32 *seq_nr)
	180	__must_hold(&tbl->slot_tbl_lock)
	181	{
	182	struct nfs4_slot *slot;
68a56400	183	int ret;
e09c978a TM	184
e09c978a TM	185	slot = nfs4_lookup_slot(tbl, slotid);
68a56400 AB	186	ret = PTR_ERR_OR_ZERO(slot);
	187	if (!ret)
	188	*seq_nr = slot->seq_nr;
	189
	190	return ret;
e09c978a TM	191	}
	192
	193	/*
	194	* nfs4_slot_seqid_in_use - test if a slot sequence id is still in use
	195	*
	196	* Given a slot table, slot id and sequence number, determine if the
	197	* RPC call in question is still in flight. This function is mainly
	198	* intended for use by the callback channel.
	199	*/
045d2a6d TM	200	static bool nfs4_slot_seqid_in_use(struct nfs4_slot_table *tbl,
045d2a6d TM	201	u32 slotid, u32 seq_nr)
e09c978a	202	{
0ac84b72	203	u32 cur_seq = 0;
e09c978a TM	204	bool ret = false;
	205
	206	spin_lock(&tbl->slot_tbl_lock);
	207	if (nfs4_slot_get_seqid(tbl, slotid, &cur_seq) == 0 &&
	208	cur_seq == seq_nr && test_bit(slotid, tbl->used_slots))
	209	ret = true;
	210	spin_unlock(&tbl->slot_tbl_lock);
	211	return ret;
	212	}
	213
045d2a6d TM	214	/*
	215	* nfs4_slot_wait_on_seqid - wait until a slot sequence id is complete
	216	*
	217	* Given a slot table, slot id and sequence number, wait until the
	218	* corresponding RPC call completes. This function is mainly
	219	* intended for use by the callback channel.
	220	*/
	221	int nfs4_slot_wait_on_seqid(struct nfs4_slot_table *tbl,
	222	u32 slotid, u32 seq_nr,
	223	unsigned long timeout)
	224	{
	225	if (wait_event_timeout(tbl->slot_waitq,
	226	!nfs4_slot_seqid_in_use(tbl, slotid, seq_nr),
	227	timeout) == 0)
	228	return -ETIMEDOUT;
	229	return 0;
	230	}
	231
73e39aaa TM	232	/*
	233	* nfs4_alloc_slot - efficiently look for a free slot
	234	*
	235	* nfs4_alloc_slot looks for an unset bit in the used_slots bitmap.
	236	* If found, we mark the slot as used, update the highest_used_slotid,
	237	* and respectively set up the sequence operation args.
	238	*
	239	* Note: must be called with under the slot_tbl_lock.
	240	*/
	241	struct nfs4_slot nfs4_alloc_slot(struct nfs4_slot_table tbl)
	242	{
	243	struct nfs4_slot *ret = ERR_PTR(-EBUSY);
	244	u32 slotid;
	245
	246	dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n",
	247	__func__, tbl->used_slots[0], tbl->highest_used_slotid,
	248	tbl->max_slotid + 1);
	249	slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1);
810d82e6 TM	250	if (slotid <= tbl->max_slotid) {
	251	ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
	252	if (!IS_ERR(ret))
	253	nfs4_lock_slot(tbl, ret);
	254	}
e8d92382	255	dprintk("<-- %s used_slots=%04lx highest_used=%u slotid=%u\n",
73e39aaa	256	__func__, tbl->used_slots[0], tbl->highest_used_slotid,
e8d92382	257	!IS_ERR(ret) ? ret->slot_nr : NFS4_NO_SLOT);
73e39aaa TM	258	return ret;
	259	}
	260
	261	static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl,
	262	u32 max_reqs, u32 ivalue)
	263	{
	264	if (max_reqs <= tbl->max_slots)
	265	return 0;
	266	if (!IS_ERR(nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS)))
	267	return 0;
	268	return -ENOMEM;
	269	}
	270
	271	static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
	272	u32 server_highest_slotid,
	273	u32 ivalue)
	274	{
	275	struct nfs4_slot **p;
	276
	277	nfs4_shrink_slot_table(tbl, server_highest_slotid + 1);
	278	p = &tbl->slots;
	279	while (*p) {
	280	(*p)->seq_nr = ivalue;
3453d570 TM	281	(*p)->seq_nr_highest_sent = ivalue;
3453d570 TM	282	(*p)->seq_nr_last_acked = ivalue - 1;
73e39aaa TM	283	p = &(*p)->next;
	284	}
	285	tbl->highest_used_slotid = NFS4_NO_SLOT;
	286	tbl->target_highest_slotid = server_highest_slotid;
	287	tbl->server_highest_slotid = server_highest_slotid;
1fa80644 TM	288	tbl->d_target_highest_slotid = 0;
1fa80644 TM	289	tbl->d2_target_highest_slotid = 0;
73e39aaa TM	290	tbl->max_slotid = server_highest_slotid;
	291	}
	292
	293	/*
	294	* (re)Initialise a slot table
	295	*/
	296	static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl,
	297	u32 max_reqs, u32 ivalue)
	298	{
	299	int ret;
	300
e8d92382	301	dprintk("--> %s: max_reqs=%u, tbl->max_slots %u\n", __func__,
73e39aaa TM	302	max_reqs, tbl->max_slots);
	303
	304	if (max_reqs > NFS4_MAX_SLOT_TABLE)
	305	max_reqs = NFS4_MAX_SLOT_TABLE;
	306
	307	ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue);
	308	if (ret)
	309	goto out;
	310
	311	spin_lock(&tbl->slot_tbl_lock);
	312	nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue);
	313	spin_unlock(&tbl->slot_tbl_lock);
	314
e8d92382	315	dprintk("%s: tbl=%p slots=%p max_slots=%u\n", __func__,
73e39aaa TM	316	tbl, tbl->slots, tbl->max_slots);
	317	out:
	318	dprintk("<-- %s: return %d\n", __func__, ret);
	319	return ret;
	320	}
	321
20b9a902 TM	322	/*
	323	* nfs4_release_slot_table - release all slot table entries
	324	*/
	325	static void nfs4_release_slot_table(struct nfs4_slot_table *tbl)
	326	{
	327	nfs4_shrink_slot_table(tbl, 0);
	328	}
	329
eb2a1cd3	330	/**
20b9a902	331	* nfs4_shutdown_slot_table - release resources attached to a slot table
eb2a1cd3 CL	332	* @tbl: slot table to shut down
	333	*
	334	*/
20b9a902	335	void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl)
eb2a1cd3	336	{
20b9a902 TM	337	nfs4_release_slot_table(tbl);
20b9a902 TM	338	rpc_destroy_wait_queue(&tbl->slot_tbl_waitq);
eb2a1cd3 CL	339	}
eb2a1cd3 CL	340
744aa525 CL	341	/**
	342	* nfs4_setup_slot_table - prepare a stand-alone slot table for use
	343	* @tbl: slot table to set up
	344	* @max_reqs: maximum number of requests allowed
	345	* @queue: name to give RPC wait queue
	346	*
	347	* Returns zero on success, or a negative errno.
	348	*/
	349	int nfs4_setup_slot_table(struct nfs4_slot_table *tbl, unsigned int max_reqs,
	350	const char *queue)
	351	{
	352	nfs4_init_slot_table(tbl, queue);
	353	return nfs4_realloc_slot_table(tbl, max_reqs, 0);
	354	}
	355
b75ad4cd TM	356	static bool nfs41_assign_slot(struct rpc_task task, void pslot)
	357	{
	358	struct nfs4_sequence_args *args = task->tk_msg.rpc_argp;
	359	struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;
	360	struct nfs4_slot *slot = pslot;
	361	struct nfs4_slot_table *tbl = slot->table;
	362
774d5f14	363	if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged)
b75ad4cd	364	return false;
b75ad4cd TM	365	slot->generation = tbl->generation;
b75ad4cd TM	366	args->sa_slot = slot;
8e63b6a8	367	res->sr_timestamp = jiffies;
b75ad4cd TM	368	res->sr_slot = slot;
	369	res->sr_status_flags = 0;
	370	res->sr_status = 1;
	371	return true;
	372	}
	373
	374	static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
	375	struct nfs4_slot *slot)
	376	{
	377	if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot))
	378	return true;
	379	return false;
	380	}
	381
	382	bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
	383	struct nfs4_slot *slot)
	384	{
	385	if (slot->slot_nr > tbl->max_slotid)
	386	return false;
	387	return __nfs41_wake_and_assign_slot(tbl, slot);
	388	}
	389
	390	static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl)
	391	{
	392	struct nfs4_slot *slot = nfs4_alloc_slot(tbl);
	393	if (!IS_ERR(slot)) {
	394	bool ret = __nfs41_wake_and_assign_slot(tbl, slot);
	395	if (ret)
	396	return ret;
	397	nfs4_free_slot(tbl, slot);
	398	}
	399	return false;
	400	}
	401
	402	void nfs41_wake_slot_table(struct nfs4_slot_table *tbl)
	403	{
	404	for (;;) {
	405	if (!nfs41_try_wake_next_slot_table_entry(tbl))
	406	break;
	407	}
	408	}
	409
1cec16ab CL	410	#if defined(CONFIG_NFS_V4_1)
1cec16ab CL	411
b0ef9647 TM	412	static void nfs41_set_max_slotid_locked(struct nfs4_slot_table *tbl,
	413	u32 target_highest_slotid)
	414	{
	415	u32 max_slotid;
	416
	417	max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, target_highest_slotid);
	418	if (max_slotid > tbl->server_highest_slotid)
	419	max_slotid = tbl->server_highest_slotid;
	420	if (max_slotid > tbl->target_highest_slotid)
	421	max_slotid = tbl->target_highest_slotid;
	422	tbl->max_slotid = max_slotid;
	423	nfs41_wake_slot_table(tbl);
	424	}
	425
73e39aaa TM	426	/* Update the client's idea of target_highest_slotid */
	427	static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,
	428	u32 target_highest_slotid)
	429	{
73e39aaa TM	430	if (tbl->target_highest_slotid == target_highest_slotid)
	431	return;
	432	tbl->target_highest_slotid = target_highest_slotid;
	433	tbl->generation++;
73e39aaa TM	434	}
	435
	436	void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
	437	u32 target_highest_slotid)
	438	{
	439	spin_lock(&tbl->slot_tbl_lock);
	440	nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
1fa80644 TM	441	tbl->d_target_highest_slotid = 0;
1fa80644 TM	442	tbl->d2_target_highest_slotid = 0;
b0ef9647	443	nfs41_set_max_slotid_locked(tbl, target_highest_slotid);
73e39aaa TM	444	spin_unlock(&tbl->slot_tbl_lock);
	445	}
	446
	447	static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl,
	448	u32 highest_slotid)
	449	{
	450	if (tbl->server_highest_slotid == highest_slotid)
	451	return;
	452	if (tbl->highest_used_slotid > highest_slotid)
	453	return;
	454	/* Deallocate slots */
	455	nfs4_shrink_slot_table(tbl, highest_slotid + 1);
	456	tbl->server_highest_slotid = highest_slotid;
	457	}
	458
1fa80644 TM	459	static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2)
	460	{
	461	s1 -= s2;
	462	if (s1 == 0)
	463	return 0;
	464	if (s1 < 0)
	465	return (s1 - 1) >> 1;
	466	return (s1 + 1) >> 1;
	467	}
	468
	469	static int nfs41_sign_s32(s32 s1)
	470	{
	471	if (s1 > 0)
	472	return 1;
	473	if (s1 < 0)
	474	return -1;
	475	return 0;
	476	}
	477
	478	static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2)
	479	{
	480	if (!s1 \|\| !s2)
	481	return true;
	482	return nfs41_sign_s32(s1) == nfs41_sign_s32(s2);
	483	}
	484
	485	/* Try to eliminate outliers by checking for sharp changes in the
	486	* derivatives and second derivatives
	487	*/
	488	static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl,
	489	u32 new_target)
	490	{
	491	s32 d_target, d2_target;
	492	bool ret = true;
	493
	494	d_target = nfs41_derivative_target_slotid(new_target,
	495	tbl->target_highest_slotid);
	496	d2_target = nfs41_derivative_target_slotid(d_target,
	497	tbl->d_target_highest_slotid);
	498	/* Is first derivative same sign? */
	499	if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid))
	500	ret = false;
	501	/* Is second derivative same sign? */
	502	if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid))
	503	ret = false;
	504	tbl->d_target_highest_slotid = d_target;
	505	tbl->d2_target_highest_slotid = d2_target;
	506	return ret;
	507	}
	508
73e39aaa TM	509	void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
	510	struct nfs4_slot *slot,
	511	struct nfs4_sequence_res *res)
	512	{
	513	spin_lock(&tbl->slot_tbl_lock);
1fa80644 TM	514	if (!nfs41_is_outlier_target_slotid(tbl, res->sr_target_highest_slotid))
	515	nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
	516	if (tbl->generation == slot->generation)
	517	nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
b0ef9647	518	nfs41_set_max_slotid_locked(tbl, res->sr_target_highest_slotid);
73e39aaa TM	519	spin_unlock(&tbl->slot_tbl_lock);
	520	}
	521
20b9a902	522	static void nfs4_release_session_slot_tables(struct nfs4_session *session)
9d33059c	523	{
eb2a1cd3 CL	524	nfs4_release_slot_table(&session->fc_slot_table);
eb2a1cd3 CL	525	nfs4_release_slot_table(&session->bc_slot_table);
9d33059c CL	526	}
9d33059c CL	527
73e39aaa TM	528	/*
	529	* Initialize or reset the forechannel and backchannel tables
	530	*/
	531	int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
	532	{
	533	struct nfs4_slot_table *tbl;
	534	int status;
	535
	536	dprintk("--> %s\n", __func__);
	537	/* Fore channel */
	538	tbl = &ses->fc_slot_table;
	539	tbl->session = ses;
	540	status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
b1c0df5f	541	if (status \|\| !(ses->flags & SESSION4_BACK_CHAN)) /* -ENOMEM */
73e39aaa TM	542	return status;
	543	/* Back channel */
	544	tbl = &ses->bc_slot_table;
	545	tbl->session = ses;
	546	status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
	547	if (status && tbl->slots == NULL)
	548	/* Fore and back channel share a connection so get
	549	* both slot tables or neither */
20b9a902	550	nfs4_release_session_slot_tables(ses);
73e39aaa TM	551	return status;
	552	}
	553
	554	struct nfs4_session nfs4_alloc_session(struct nfs_client clp)
	555	{
	556	struct nfs4_session *session;
73e39aaa TM	557
	558	session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
	559	if (!session)
	560	return NULL;
	561
744aa525 CL	562	nfs4_init_slot_table(&session->fc_slot_table, "ForeChannel Slot table");
744aa525 CL	563	nfs4_init_slot_table(&session->bc_slot_table, "BackChannel Slot table");
73e39aaa TM	564	session->session_state = 1<<NFS4_SESSION_INITING;
	565
	566	session->clp = clp;
	567	return session;
	568	}
	569
20b9a902 TM	570	static void nfs4_destroy_session_slot_tables(struct nfs4_session *session)
	571	{
	572	nfs4_shutdown_slot_table(&session->fc_slot_table);
	573	nfs4_shutdown_slot_table(&session->bc_slot_table);
	574	}
	575
73e39aaa TM	576	void nfs4_destroy_session(struct nfs4_session *session)
	577	{
	578	struct rpc_xprt *xprt;
a52458b4	579	const struct cred *cred;
73e39aaa	580
73d8bde5	581	cred = nfs4_get_clid_cred(session->clp);
73e39aaa	582	nfs4_proc_destroy_session(session, cred);
a52458b4	583	put_cred(cred);
73e39aaa TM	584
	585	rcu_read_lock();
	586	xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt);
	587	rcu_read_unlock();
	588	dprintk("%s Destroy backchannel for xprt %p\n",
	589	__func__, xprt);
	590	xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
eb2a1cd3	591	nfs4_destroy_session_slot_tables(session);
73e39aaa TM	592	kfree(session);
	593	}
	594
	595	/*
	596	* With sessions, the client is not marked ready until after a
	597	* successful EXCHANGE_ID and CREATE_SESSION.
	598	*
	599	* Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate
	600	* other versions of NFS can be tried.
	601	*/
	602	static int nfs41_check_session_ready(struct nfs_client *clp)
	603	{
	604	int ret;
	605
	606	if (clp->cl_cons_state == NFS_CS_SESSION_INITING) {
	607	ret = nfs4_client_recover_expired_lease(clp);
	608	if (ret)
	609	return ret;
	610	}
	611	if (clp->cl_cons_state < NFS_CS_READY)
	612	return -EPROTONOSUPPORT;
	613	smp_rmb();
	614	return 0;
	615	}
	616
18aad3d5	617	int nfs4_init_session(struct nfs_client *clp)
73e39aaa	618	{
73e39aaa TM	619	if (!nfs4_has_session(clp))
	620	return 0;
	621
18aad3d5	622	clear_bit(NFS4_SESSION_INITING, &clp->cl_session->session_state);
73e39aaa TM	623	return nfs41_check_session_ready(clp);
	624	}
	625
	626	int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time)
	627	{
	628	struct nfs4_session *session = clp->cl_session;
	629	int ret;
	630
	631	spin_lock(&clp->cl_lock);
	632	if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
	633	/*
	634	* Do not set NFS_CS_CHECK_LEASE_TIME instead set the
	635	* DS lease to be equal to the MDS lease.
	636	*/
	637	clp->cl_lease_time = lease_time;
	638	clp->cl_last_renewal = jiffies;
	639	}
	640	spin_unlock(&clp->cl_lock);
	641
	642	ret = nfs41_check_session_ready(clp);
	643	if (ret)
	644	return ret;
	645	/* Test for the DS role */
	646	if (!is_ds_client(clp))
	647	return -ENODEV;
	648	return 0;
	649	}
	650	EXPORT_SYMBOL_GPL(nfs4_init_ds_session);
	651
9d33059c	652	#endif /* defined(CONFIG_NFS_V4_1) */