linux/fs/nfs/client.c

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/* client.c: NFS client sharing and management code
*
* Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/metrics.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/nfs4_mount.h>
#include <linux/lockd/bind.h>
#include <linux/smp_lock.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <linux/nfs_idmap.h>
#include <linux/vfs.h>
#include <linux/inet.h>
#include <linux/nfs_xdr.h>
#include <asm/system.h>
#include "nfs4_fs.h"
#include "callback.h"
#include "delegation.h"
#include "iostat.h"
#include "internal.h"
#define NFSDBG_FACILITY NFSDBG_CLIENT
static DEFINE_SPINLOCK(nfs_client_lock);
static LIST_HEAD(nfs_client_list);
static DECLARE_WAIT_QUEUE_HEAD(nfs_client_active_wq);
/*
* Allocate a shared client record
*
* Since these are allocated/deallocated very rarely, we don't
* bother putting them in a slab cache...
*/
static struct nfs_client *nfs_alloc_client(const char *hostname,
const struct sockaddr_in *addr,
int nfsversion)
{
struct nfs_client *clp;
int error;
if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
goto error_0;
error = rpciod_up();
if (error < 0) {
dprintk("%s: couldn't start rpciod! Error = %d\n",
__FUNCTION__, error);
__set_bit(NFS_CS_RPCIOD, &clp->cl_res_state);
goto error_1;
}
if (nfsversion == 4) {
if (nfs_callback_up() < 0)
goto error_2;
__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
}
atomic_set(&clp->cl_count, 1);
clp->cl_cons_state = NFS_CS_INITING;
clp->cl_nfsversion = nfsversion;
memcpy(&clp->cl_addr, addr, sizeof(clp->cl_addr));
if (hostname) {
clp->cl_hostname = kstrdup(hostname, GFP_KERNEL);
if (!clp->cl_hostname)
goto error_3;
}
INIT_LIST_HEAD(&clp->cl_superblocks);
clp->cl_rpcclient = ERR_PTR(-EINVAL);
#ifdef CONFIG_NFS_V4
init_rwsem(&clp->cl_sem);
INIT_LIST_HEAD(&clp->cl_delegations);
INIT_LIST_HEAD(&clp->cl_state_owners);
INIT_LIST_HEAD(&clp->cl_unused);
spin_lock_init(&clp->cl_lock);
INIT_WORK(&clp->cl_renewd, nfs4_renew_state, clp);
rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
clp->cl_boot_time = CURRENT_TIME;
clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
#endif
return clp;
error_3:
nfs_callback_down();
__clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
error_2:
rpciod_down();
__clear_bit(NFS_CS_RPCIOD, &clp->cl_res_state);
error_1:
kfree(clp);
error_0:
return NULL;
}
/*
* Destroy a shared client record
*/
static void nfs_free_client(struct nfs_client *clp)
{
dprintk("--> nfs_free_client(%d)\n", clp->cl_nfsversion);
#ifdef CONFIG_NFS_V4
if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state)) {
while (!list_empty(&clp->cl_unused)) {
struct nfs4_state_owner *sp;
sp = list_entry(clp->cl_unused.next,
struct nfs4_state_owner,
so_list);
list_del(&sp->so_list);
kfree(sp);
}
BUG_ON(!list_empty(&clp->cl_state_owners));
nfs_idmap_delete(clp);
}
#endif
/* -EIO all pending I/O */
if (!IS_ERR(clp->cl_rpcclient))
rpc_shutdown_client(clp->cl_rpcclient);
if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
nfs_callback_down();
if (__test_and_clear_bit(NFS_CS_RPCIOD, &clp->cl_res_state))
rpciod_down();
kfree(clp->cl_hostname);
kfree(clp);
dprintk("<-- nfs_free_client()\n");
}
/*
* Release a reference to a shared client record
*/
void nfs_put_client(struct nfs_client *clp)
{
dprintk("--> nfs_put_client({%d})\n", atomic_read(&clp->cl_count));
if (atomic_dec_and_lock(&clp->cl_count, &nfs_client_lock)) {
list_del(&clp->cl_share_link);
spin_unlock(&nfs_client_lock);
BUG_ON(!list_empty(&clp->cl_superblocks));
nfs_free_client(clp);
}
}
/*
* Find a client by address
* - caller must hold nfs_client_lock
*/
static struct nfs_client *__nfs_find_client(const struct sockaddr_in *addr, int nfsversion)
{
struct nfs_client *clp;
list_for_each_entry(clp, &nfs_client_list, cl_share_link) {
/* Different NFS versions cannot share the same nfs_client */
if (clp->cl_nfsversion != nfsversion)
continue;
if (memcmp(&clp->cl_addr.sin_addr, &addr->sin_addr,
sizeof(clp->cl_addr.sin_addr)) != 0)
continue;
if (clp->cl_addr.sin_port == addr->sin_port)
goto found;
}
return NULL;
found:
atomic_inc(&clp->cl_count);
return clp;
}
/*
* Find a client by IP address and protocol version
* - returns NULL if no such client
*/
struct nfs_client *nfs_find_client(const struct sockaddr_in *addr, int nfsversion)
{
struct nfs_client *clp;
spin_lock(&nfs_client_lock);
clp = __nfs_find_client(addr, nfsversion);
spin_unlock(&nfs_client_lock);
BUG_ON(clp->cl_cons_state == 0);
return clp;
}
/*
* Look up a client by IP address and protocol version
* - creates a new record if one doesn't yet exist
*/
struct nfs_client *nfs_get_client(const char *hostname,
const struct sockaddr_in *addr,
int nfsversion)
{
struct nfs_client *clp, *new = NULL;
int error;
dprintk("--> nfs_get_client(%s,"NIPQUAD_FMT":%d,%d)\n",
hostname ?: "", NIPQUAD(addr->sin_addr),
addr->sin_port, nfsversion);
/* see if the client already exists */
do {
spin_lock(&nfs_client_lock);
clp = __nfs_find_client(addr, nfsversion);
if (clp)
goto found_client;
if (new)
goto install_client;
spin_unlock(&nfs_client_lock);
new = nfs_alloc_client(hostname, addr, nfsversion);
} while (new);
return ERR_PTR(-ENOMEM);
/* install a new client and return with it unready */
install_client:
clp = new;
list_add(&clp->cl_share_link, &nfs_client_list);
spin_unlock(&nfs_client_lock);
dprintk("--> nfs_get_client() = %p [new]\n", clp);
return clp;
/* found an existing client
* - make sure it's ready before returning
*/
found_client:
spin_unlock(&nfs_client_lock);
if (new)
nfs_free_client(new);
if (clp->cl_cons_state == NFS_CS_INITING) {
DECLARE_WAITQUEUE(myself, current);
add_wait_queue(&nfs_client_active_wq, &myself);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (signal_pending(current) ||
clp->cl_cons_state > NFS_CS_READY)
break;
schedule();
}
remove_wait_queue(&nfs_client_active_wq, &myself);
if (signal_pending(current)) {
nfs_put_client(clp);
return ERR_PTR(-ERESTARTSYS);
}
}
if (clp->cl_cons_state < NFS_CS_READY) {
error = clp->cl_cons_state;
nfs_put_client(clp);
return ERR_PTR(error);
}
dprintk("--> nfs_get_client() = %p [share]\n", clp);
return clp;
}
/*
* Mark a server as ready or failed
*/
void nfs_mark_client_ready(struct nfs_client *clp, int state)
{
clp->cl_cons_state = state;
wake_up_all(&nfs_client_active_wq);
}