[mirror_ubuntu-bionic-kernel.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;
	}
	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, 1, 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;

	slot = nfs4_lookup_slot(tbl, slotid);
	if (IS_ERR(slot))
		return PTR_ERR(slot);
	*seq_nr = slot->seq_nr;
	return 0;
}

/*
 * 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;
	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)->interrupted = 0;
		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;
	struct rpc_cred *cred;

	cred = nfs4_get_clid_cred(session->clp);
	nfs4_proc_destroy_session(session, cred);
	if (cred)
		put_rpccred(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	/**
	57	* nfs4_slot_tbl_drain_complete - wake waiters when drain is complete
	58	* @tbl - controlling slot table
	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;
	113	}
	114	return slot;
	115	}
	116
	117	static struct nfs4_slot nfs4_find_or_create_slot(struct nfs4_slot_table tbl,
	118	u32 slotid, u32 seq_init, gfp_t gfp_mask)
	119	{
	120	struct nfs4_slot *p, slot;
	121
	122	p = &tbl->slots;
	123	for (;;) {
	124	if (*p == NULL) {
	125	*p = nfs4_new_slot(tbl, tbl->max_slots,
	126	seq_init, gfp_mask);
	127	if (*p == NULL)
	128	break;
	129	tbl->max_slots++;
	130	}
	131	slot = *p;
	132	if (slot->slot_nr == slotid)
	133	return slot;
	134	p = &slot->next;
	135	}
	136	return ERR_PTR(-ENOMEM);
	137	}
	138
810d82e6 TM	139	static void nfs4_lock_slot(struct nfs4_slot_table *tbl,
	140	struct nfs4_slot *slot)
	141	{
	142	u32 slotid = slot->slot_nr;
	143
	144	__set_bit(slotid, tbl->used_slots);
	145	if (slotid > tbl->highest_used_slotid \|\|
	146	tbl->highest_used_slotid == NFS4_NO_SLOT)
	147	tbl->highest_used_slotid = slotid;
	148	slot->generation = tbl->generation;
	149	}
	150
	151	/*
	152	* nfs4_try_to_lock_slot - Given a slot try to allocate it
	153	*
	154	* Note: must be called with the slot_tbl_lock held.
	155	*/
	156	bool nfs4_try_to_lock_slot(struct nfs4_slot_table tbl, struct nfs4_slot slot)
	157	{
	158	if (nfs4_test_locked_slot(tbl, slot->slot_nr))
	159	return false;
	160	nfs4_lock_slot(tbl, slot);
	161	return true;
	162	}
	163
	164	/*
	165	* nfs4_lookup_slot - Find a slot but don't allocate it
	166	*
	167	* Note: must be called with the slot_tbl_lock held.
	168	*/
	169	struct nfs4_slot nfs4_lookup_slot(struct nfs4_slot_table tbl, u32 slotid)
	170	{
	171	if (slotid <= tbl->max_slotid)
	172	return nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
	173	return ERR_PTR(-E2BIG);
	174	}
	175
e09c978a TM	176	static int nfs4_slot_get_seqid(struct nfs4_slot_table *tbl, u32 slotid,
	177	u32 *seq_nr)
	178	__must_hold(&tbl->slot_tbl_lock)
	179	{
	180	struct nfs4_slot *slot;
	181
	182	slot = nfs4_lookup_slot(tbl, slotid);
	183	if (IS_ERR(slot))
	184	return PTR_ERR(slot);
	185	*seq_nr = slot->seq_nr;
	186	return 0;
	187	}
	188
	189	/*
	190	* nfs4_slot_seqid_in_use - test if a slot sequence id is still in use
	191	*
	192	* Given a slot table, slot id and sequence number, determine if the
	193	* RPC call in question is still in flight. This function is mainly
	194	* intended for use by the callback channel.
	195	*/
045d2a6d TM	196	static bool nfs4_slot_seqid_in_use(struct nfs4_slot_table *tbl,
045d2a6d TM	197	u32 slotid, u32 seq_nr)
e09c978a TM	198	{
	199	u32 cur_seq;
	200	bool ret = false;
	201
	202	spin_lock(&tbl->slot_tbl_lock);
	203	if (nfs4_slot_get_seqid(tbl, slotid, &cur_seq) == 0 &&
	204	cur_seq == seq_nr && test_bit(slotid, tbl->used_slots))
	205	ret = true;
	206	spin_unlock(&tbl->slot_tbl_lock);
	207	return ret;
	208	}
	209
045d2a6d TM	210	/*
	211	* nfs4_slot_wait_on_seqid - wait until a slot sequence id is complete
	212	*
	213	* Given a slot table, slot id and sequence number, wait until the
	214	* corresponding RPC call completes. This function is mainly
	215	* intended for use by the callback channel.
	216	*/
	217	int nfs4_slot_wait_on_seqid(struct nfs4_slot_table *tbl,
	218	u32 slotid, u32 seq_nr,
	219	unsigned long timeout)
	220	{
	221	if (wait_event_timeout(tbl->slot_waitq,
	222	!nfs4_slot_seqid_in_use(tbl, slotid, seq_nr),
	223	timeout) == 0)
	224	return -ETIMEDOUT;
	225	return 0;
	226	}
	227
73e39aaa TM	228	/*
	229	* nfs4_alloc_slot - efficiently look for a free slot
	230	*
	231	* nfs4_alloc_slot looks for an unset bit in the used_slots bitmap.
	232	* If found, we mark the slot as used, update the highest_used_slotid,
	233	* and respectively set up the sequence operation args.
	234	*
	235	* Note: must be called with under the slot_tbl_lock.
	236	*/
	237	struct nfs4_slot nfs4_alloc_slot(struct nfs4_slot_table tbl)
	238	{
	239	struct nfs4_slot *ret = ERR_PTR(-EBUSY);
	240	u32 slotid;
	241
	242	dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n",
	243	__func__, tbl->used_slots[0], tbl->highest_used_slotid,
	244	tbl->max_slotid + 1);
	245	slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1);
810d82e6 TM	246	if (slotid <= tbl->max_slotid) {
	247	ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
	248	if (!IS_ERR(ret))
	249	nfs4_lock_slot(tbl, ret);
	250	}
e8d92382	251	dprintk("<-- %s used_slots=%04lx highest_used=%u slotid=%u\n",
73e39aaa	252	__func__, tbl->used_slots[0], tbl->highest_used_slotid,
e8d92382	253	!IS_ERR(ret) ? ret->slot_nr : NFS4_NO_SLOT);
73e39aaa TM	254	return ret;
	255	}
	256
	257	static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl,
	258	u32 max_reqs, u32 ivalue)
	259	{
	260	if (max_reqs <= tbl->max_slots)
	261	return 0;
	262	if (!IS_ERR(nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS)))
	263	return 0;
	264	return -ENOMEM;
	265	}
	266
	267	static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
	268	u32 server_highest_slotid,
	269	u32 ivalue)
	270	{
	271	struct nfs4_slot **p;
	272
	273	nfs4_shrink_slot_table(tbl, server_highest_slotid + 1);
	274	p = &tbl->slots;
	275	while (*p) {
	276	(*p)->seq_nr = ivalue;
ac20d163	277	(*p)->interrupted = 0;
73e39aaa TM	278	p = &(*p)->next;
	279	}
	280	tbl->highest_used_slotid = NFS4_NO_SLOT;
	281	tbl->target_highest_slotid = server_highest_slotid;
	282	tbl->server_highest_slotid = server_highest_slotid;
1fa80644 TM	283	tbl->d_target_highest_slotid = 0;
1fa80644 TM	284	tbl->d2_target_highest_slotid = 0;
73e39aaa TM	285	tbl->max_slotid = server_highest_slotid;
	286	}
	287
	288	/*
	289	* (re)Initialise a slot table
	290	*/
	291	static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl,
	292	u32 max_reqs, u32 ivalue)
	293	{
	294	int ret;
	295
e8d92382	296	dprintk("--> %s: max_reqs=%u, tbl->max_slots %u\n", __func__,
73e39aaa TM	297	max_reqs, tbl->max_slots);
	298
	299	if (max_reqs > NFS4_MAX_SLOT_TABLE)
	300	max_reqs = NFS4_MAX_SLOT_TABLE;
	301
	302	ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue);
	303	if (ret)
	304	goto out;
	305
	306	spin_lock(&tbl->slot_tbl_lock);
	307	nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue);
	308	spin_unlock(&tbl->slot_tbl_lock);
	309
e8d92382	310	dprintk("%s: tbl=%p slots=%p max_slots=%u\n", __func__,
73e39aaa TM	311	tbl, tbl->slots, tbl->max_slots);
	312	out:
	313	dprintk("<-- %s: return %d\n", __func__, ret);
	314	return ret;
	315	}
	316
20b9a902 TM	317	/*
	318	* nfs4_release_slot_table - release all slot table entries
	319	*/
	320	static void nfs4_release_slot_table(struct nfs4_slot_table *tbl)
	321	{
	322	nfs4_shrink_slot_table(tbl, 0);
	323	}
	324
eb2a1cd3	325	/**
20b9a902	326	* nfs4_shutdown_slot_table - release resources attached to a slot table
eb2a1cd3 CL	327	* @tbl: slot table to shut down
	328	*
	329	*/
20b9a902	330	void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl)
eb2a1cd3	331	{
20b9a902 TM	332	nfs4_release_slot_table(tbl);
20b9a902 TM	333	rpc_destroy_wait_queue(&tbl->slot_tbl_waitq);
eb2a1cd3 CL	334	}
eb2a1cd3 CL	335
744aa525 CL	336	/**
	337	* nfs4_setup_slot_table - prepare a stand-alone slot table for use
	338	* @tbl: slot table to set up
	339	* @max_reqs: maximum number of requests allowed
	340	* @queue: name to give RPC wait queue
	341	*
	342	* Returns zero on success, or a negative errno.
	343	*/
	344	int nfs4_setup_slot_table(struct nfs4_slot_table *tbl, unsigned int max_reqs,
	345	const char *queue)
	346	{
	347	nfs4_init_slot_table(tbl, queue);
	348	return nfs4_realloc_slot_table(tbl, max_reqs, 0);
	349	}
	350
b75ad4cd TM	351	static bool nfs41_assign_slot(struct rpc_task task, void pslot)
	352	{
	353	struct nfs4_sequence_args *args = task->tk_msg.rpc_argp;
	354	struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;
	355	struct nfs4_slot *slot = pslot;
	356	struct nfs4_slot_table *tbl = slot->table;
	357
774d5f14	358	if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged)
b75ad4cd	359	return false;
b75ad4cd TM	360	slot->generation = tbl->generation;
b75ad4cd TM	361	args->sa_slot = slot;
8e63b6a8	362	res->sr_timestamp = jiffies;
b75ad4cd TM	363	res->sr_slot = slot;
	364	res->sr_status_flags = 0;
	365	res->sr_status = 1;
	366	return true;
	367	}
	368
	369	static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
	370	struct nfs4_slot *slot)
	371	{
	372	if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot))
	373	return true;
	374	return false;
	375	}
	376
	377	bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
	378	struct nfs4_slot *slot)
	379	{
	380	if (slot->slot_nr > tbl->max_slotid)
	381	return false;
	382	return __nfs41_wake_and_assign_slot(tbl, slot);
	383	}
	384
	385	static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl)
	386	{
	387	struct nfs4_slot *slot = nfs4_alloc_slot(tbl);
	388	if (!IS_ERR(slot)) {
	389	bool ret = __nfs41_wake_and_assign_slot(tbl, slot);
	390	if (ret)
	391	return ret;
	392	nfs4_free_slot(tbl, slot);
	393	}
	394	return false;
	395	}
	396
	397	void nfs41_wake_slot_table(struct nfs4_slot_table *tbl)
	398	{
	399	for (;;) {
	400	if (!nfs41_try_wake_next_slot_table_entry(tbl))
	401	break;
	402	}
	403	}
	404
1cec16ab CL	405	#if defined(CONFIG_NFS_V4_1)
1cec16ab CL	406
b0ef9647 TM	407	static void nfs41_set_max_slotid_locked(struct nfs4_slot_table *tbl,
	408	u32 target_highest_slotid)
	409	{
	410	u32 max_slotid;
	411
	412	max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, target_highest_slotid);
	413	if (max_slotid > tbl->server_highest_slotid)
	414	max_slotid = tbl->server_highest_slotid;
	415	if (max_slotid > tbl->target_highest_slotid)
	416	max_slotid = tbl->target_highest_slotid;
	417	tbl->max_slotid = max_slotid;
	418	nfs41_wake_slot_table(tbl);
	419	}
	420
73e39aaa TM	421	/* Update the client's idea of target_highest_slotid */
	422	static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,
	423	u32 target_highest_slotid)
	424	{
73e39aaa TM	425	if (tbl->target_highest_slotid == target_highest_slotid)
	426	return;
	427	tbl->target_highest_slotid = target_highest_slotid;
	428	tbl->generation++;
73e39aaa TM	429	}
	430
	431	void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
	432	u32 target_highest_slotid)
	433	{
	434	spin_lock(&tbl->slot_tbl_lock);
	435	nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
1fa80644 TM	436	tbl->d_target_highest_slotid = 0;
1fa80644 TM	437	tbl->d2_target_highest_slotid = 0;
b0ef9647	438	nfs41_set_max_slotid_locked(tbl, target_highest_slotid);
73e39aaa TM	439	spin_unlock(&tbl->slot_tbl_lock);
	440	}
	441
	442	static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl,
	443	u32 highest_slotid)
	444	{
	445	if (tbl->server_highest_slotid == highest_slotid)
	446	return;
	447	if (tbl->highest_used_slotid > highest_slotid)
	448	return;
	449	/* Deallocate slots */
	450	nfs4_shrink_slot_table(tbl, highest_slotid + 1);
	451	tbl->server_highest_slotid = highest_slotid;
	452	}
	453
1fa80644 TM	454	static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2)
	455	{
	456	s1 -= s2;
	457	if (s1 == 0)
	458	return 0;
	459	if (s1 < 0)
	460	return (s1 - 1) >> 1;
	461	return (s1 + 1) >> 1;
	462	}
	463
	464	static int nfs41_sign_s32(s32 s1)
	465	{
	466	if (s1 > 0)
	467	return 1;
	468	if (s1 < 0)
	469	return -1;
	470	return 0;
	471	}
	472
	473	static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2)
	474	{
	475	if (!s1 \|\| !s2)
	476	return true;
	477	return nfs41_sign_s32(s1) == nfs41_sign_s32(s2);
	478	}
	479
	480	/* Try to eliminate outliers by checking for sharp changes in the
	481	* derivatives and second derivatives
	482	*/
	483	static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl,
	484	u32 new_target)
	485	{
	486	s32 d_target, d2_target;
	487	bool ret = true;
	488
	489	d_target = nfs41_derivative_target_slotid(new_target,
	490	tbl->target_highest_slotid);
	491	d2_target = nfs41_derivative_target_slotid(d_target,
	492	tbl->d_target_highest_slotid);
	493	/* Is first derivative same sign? */
	494	if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid))
	495	ret = false;
	496	/* Is second derivative same sign? */
	497	if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid))
	498	ret = false;
	499	tbl->d_target_highest_slotid = d_target;
	500	tbl->d2_target_highest_slotid = d2_target;
	501	return ret;
	502	}
	503
73e39aaa TM	504	void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
	505	struct nfs4_slot *slot,
	506	struct nfs4_sequence_res *res)
	507	{
	508	spin_lock(&tbl->slot_tbl_lock);
1fa80644 TM	509	if (!nfs41_is_outlier_target_slotid(tbl, res->sr_target_highest_slotid))
	510	nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
	511	if (tbl->generation == slot->generation)
	512	nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
b0ef9647	513	nfs41_set_max_slotid_locked(tbl, res->sr_target_highest_slotid);
73e39aaa TM	514	spin_unlock(&tbl->slot_tbl_lock);
	515	}
	516
20b9a902	517	static void nfs4_release_session_slot_tables(struct nfs4_session *session)
9d33059c	518	{
eb2a1cd3 CL	519	nfs4_release_slot_table(&session->fc_slot_table);
eb2a1cd3 CL	520	nfs4_release_slot_table(&session->bc_slot_table);
9d33059c CL	521	}
9d33059c CL	522
73e39aaa TM	523	/*
	524	* Initialize or reset the forechannel and backchannel tables
	525	*/
	526	int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
	527	{
	528	struct nfs4_slot_table *tbl;
	529	int status;
	530
	531	dprintk("--> %s\n", __func__);
	532	/* Fore channel */
	533	tbl = &ses->fc_slot_table;
	534	tbl->session = ses;
	535	status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
b1c0df5f	536	if (status \|\| !(ses->flags & SESSION4_BACK_CHAN)) /* -ENOMEM */
73e39aaa TM	537	return status;
	538	/* Back channel */
	539	tbl = &ses->bc_slot_table;
	540	tbl->session = ses;
	541	status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
	542	if (status && tbl->slots == NULL)
	543	/* Fore and back channel share a connection so get
	544	* both slot tables or neither */
20b9a902	545	nfs4_release_session_slot_tables(ses);
73e39aaa TM	546	return status;
	547	}
	548
	549	struct nfs4_session nfs4_alloc_session(struct nfs_client clp)
	550	{
	551	struct nfs4_session *session;
73e39aaa TM	552
	553	session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
	554	if (!session)
	555	return NULL;
	556
744aa525 CL	557	nfs4_init_slot_table(&session->fc_slot_table, "ForeChannel Slot table");
744aa525 CL	558	nfs4_init_slot_table(&session->bc_slot_table, "BackChannel Slot table");
73e39aaa TM	559	session->session_state = 1<<NFS4_SESSION_INITING;
	560
	561	session->clp = clp;
	562	return session;
	563	}
	564
20b9a902 TM	565	static void nfs4_destroy_session_slot_tables(struct nfs4_session *session)
	566	{
	567	nfs4_shutdown_slot_table(&session->fc_slot_table);
	568	nfs4_shutdown_slot_table(&session->bc_slot_table);
	569	}
	570
73e39aaa TM	571	void nfs4_destroy_session(struct nfs4_session *session)
	572	{
	573	struct rpc_xprt *xprt;
	574	struct rpc_cred *cred;
	575
73d8bde5	576	cred = nfs4_get_clid_cred(session->clp);
73e39aaa TM	577	nfs4_proc_destroy_session(session, cred);
	578	if (cred)
	579	put_rpccred(cred);
	580
	581	rcu_read_lock();
	582	xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt);
	583	rcu_read_unlock();
	584	dprintk("%s Destroy backchannel for xprt %p\n",
	585	__func__, xprt);
	586	xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
eb2a1cd3	587	nfs4_destroy_session_slot_tables(session);
73e39aaa TM	588	kfree(session);
	589	}
	590
	591	/*
	592	* With sessions, the client is not marked ready until after a
	593	* successful EXCHANGE_ID and CREATE_SESSION.
	594	*
	595	* Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate
	596	* other versions of NFS can be tried.
	597	*/
	598	static int nfs41_check_session_ready(struct nfs_client *clp)
	599	{
	600	int ret;
	601
	602	if (clp->cl_cons_state == NFS_CS_SESSION_INITING) {
	603	ret = nfs4_client_recover_expired_lease(clp);
	604	if (ret)
	605	return ret;
	606	}
	607	if (clp->cl_cons_state < NFS_CS_READY)
	608	return -EPROTONOSUPPORT;
	609	smp_rmb();
	610	return 0;
	611	}
	612
18aad3d5	613	int nfs4_init_session(struct nfs_client *clp)
73e39aaa	614	{
73e39aaa TM	615	if (!nfs4_has_session(clp))
	616	return 0;
	617
18aad3d5	618	clear_bit(NFS4_SESSION_INITING, &clp->cl_session->session_state);
73e39aaa TM	619	return nfs41_check_session_ready(clp);
	620	}
	621
	622	int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time)
	623	{
	624	struct nfs4_session *session = clp->cl_session;
	625	int ret;
	626
	627	spin_lock(&clp->cl_lock);
	628	if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
	629	/*
	630	* Do not set NFS_CS_CHECK_LEASE_TIME instead set the
	631	* DS lease to be equal to the MDS lease.
	632	*/
	633	clp->cl_lease_time = lease_time;
	634	clp->cl_last_renewal = jiffies;
	635	}
	636	spin_unlock(&clp->cl_lock);
	637
	638	ret = nfs41_check_session_ready(clp);
	639	if (ret)
	640	return ret;
	641	/* Test for the DS role */
	642	if (!is_ds_client(clp))
	643	return -ENODEV;
	644	return 0;
	645	}
	646	EXPORT_SYMBOL_GPL(nfs4_init_ds_session);
	647
9d33059c	648	#endif /* defined(CONFIG_NFS_V4_1) */