// SPDX-License-Identifier: GPL-2.0-only
/*
* fs/nfs/nfs4session.c
*
* Copyright (c) 2012 Trond Myklebust <[email protected]>
*
*/
#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)
{
u32 target_highest_slotid = min(res->sr_target_highest_slotid,
NFS4_MAX_SLOTID);
u32 highest_slotid = min(res->sr_highest_slotid, NFS4_MAX_SLOTID);
spin_lock(&tbl->slot_tbl_lock);
if (!nfs41_is_outlier_target_slotid(tbl, target_highest_slotid))
nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
if (tbl->generation == slot->generation)
nfs41_set_server_slotid_locked(tbl, highest_slotid);
nfs41_set_max_slotid_locked(tbl, 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) */
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