linux/fs/nfs/nfs4session.c
Trond Myklebust 73e39aaa83 NFSv4.1: Cleanup move session slot management to fs/nfs/nfs4session.c
NFSv4.1 session management is getting complex enough to deserve
a separate file.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-12-06 00:30:45 +01:00

437 lines
12 KiB
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
/*
* 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_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_session_drain_complete(tbl->session, tbl);
}
}
dprintk("%s: slotid %u highest_used_slotid %d\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);
}
/*
* 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)
goto out;
ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
if (IS_ERR(ret))
goto out;
__set_bit(slotid, tbl->used_slots);
if (slotid > tbl->highest_used_slotid ||
tbl->highest_used_slotid == NFS4_NO_SLOT)
tbl->highest_used_slotid = slotid;
ret->renewal_time = jiffies;
ret->generation = tbl->generation;
out:
dprintk("<-- %s used_slots=%04lx highest_used=%d slotid=%d \n",
__func__, tbl->used_slots[0], tbl->highest_used_slotid,
!IS_ERR(ret) ? ret->slot_nr : -1);
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 = &(*p)->next;
}
tbl->highest_used_slotid = NFS4_NO_SLOT;
tbl->target_highest_slotid = server_highest_slotid;
tbl->server_highest_slotid = server_highest_slotid;
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 %d\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=%d\n", __func__,
tbl, tbl->slots, tbl->max_slots);
out:
dprintk("<-- %s: return %d\n", __func__, ret);
return ret;
}
/* Destroy the slot table */
static void nfs4_destroy_slot_tables(struct nfs4_session *session)
{
nfs4_shrink_slot_table(&session->fc_slot_table, 0);
nfs4_shrink_slot_table(&session->bc_slot_table, 0);
}
/* 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)
{
unsigned int max_slotid, i;
if (tbl->target_highest_slotid == target_highest_slotid)
return;
tbl->target_highest_slotid = target_highest_slotid;
tbl->generation++;
max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, tbl->target_highest_slotid);
for (i = tbl->max_slotid + 1; i <= max_slotid; i++)
rpc_wake_up_next(&tbl->slot_tbl_waitq);
tbl->max_slotid = max_slotid;
}
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);
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;
}
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 (tbl->generation != slot->generation)
goto out;
nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
out:
spin_unlock(&tbl->slot_tbl_lock);
}
/*
* 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) /* -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_destroy_slot_tables(ses);
return status;
}
struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
{
struct nfs4_session *session;
struct nfs4_slot_table *tbl;
session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
if (!session)
return NULL;
tbl = &session->fc_slot_table;
tbl->highest_used_slotid = NFS4_NO_SLOT;
spin_lock_init(&tbl->slot_tbl_lock);
rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, "ForeChannel Slot table");
init_completion(&tbl->complete);
tbl = &session->bc_slot_table;
tbl->highest_used_slotid = NFS4_NO_SLOT;
spin_lock_init(&tbl->slot_tbl_lock);
rpc_init_wait_queue(&tbl->slot_tbl_waitq, "BackChannel Slot table");
init_completion(&tbl->complete);
session->session_state = 1<<NFS4_SESSION_INITING;
session->clp = clp;
return session;
}
void nfs4_destroy_session(struct nfs4_session *session)
{
struct rpc_xprt *xprt;
struct rpc_cred *cred;
cred = nfs4_get_exchange_id_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_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_server *server)
{
struct nfs_client *clp = server->nfs_client;
struct nfs4_session *session;
unsigned int target_max_rqst_sz = NFS_MAX_FILE_IO_SIZE;
unsigned int target_max_resp_sz = NFS_MAX_FILE_IO_SIZE;
if (!nfs4_has_session(clp))
return 0;
if (server->rsize != 0)
target_max_resp_sz = server->rsize;
target_max_resp_sz += nfs41_maxread_overhead;
if (server->wsize != 0)
target_max_rqst_sz = server->wsize;
target_max_rqst_sz += nfs41_maxwrite_overhead;
session = clp->cl_session;
spin_lock(&clp->cl_lock);
if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
/* Initialise targets and channel attributes */
session->fc_target_max_rqst_sz = target_max_rqst_sz;
session->fc_attrs.max_rqst_sz = target_max_rqst_sz;
session->fc_target_max_resp_sz = target_max_resp_sz;
session->fc_attrs.max_resp_sz = target_max_resp_sz;
} else {
/* Just adjust the targets */
if (target_max_rqst_sz > session->fc_target_max_rqst_sz) {
session->fc_target_max_rqst_sz = target_max_rqst_sz;
set_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state);
}
if (target_max_resp_sz > session->fc_target_max_resp_sz) {
session->fc_target_max_resp_sz = target_max_resp_sz;
set_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state);
}
}
spin_unlock(&clp->cl_lock);
if (test_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state))
nfs4_schedule_lease_recovery(clp);
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);