[deliverable/linux.git] / fs / nfs / callback.c

/*
 * linux/fs/nfs/callback.c
 *
 * Copyright (C) 2004 Trond Myklebust
 *
 * NFSv4 callback handling
 */

#include <linux/completion.h>
#include <linux/ip.h>
#include <linux/module.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/nfs_fs.h>
#include <linux/errno.h>
#include <linux/mutex.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/sunrpc/svcauth_gss.h>
#include <linux/sunrpc/bc_xprt.h>

#include <net/inet_sock.h>

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

#define NFSDBG_FACILITY NFSDBG_CALLBACK

struct nfs_callback_data {
	unsigned int users;
	struct svc_serv *serv;
	struct svc_rqst *rqst;
	struct task_struct *task;
};

static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
static DEFINE_MUTEX(nfs_callback_mutex);
static struct svc_program nfs4_callback_program;

static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net)
{
	int ret;
	struct nfs_net *nn = net_generic(net, nfs_net_id);

	ret = svc_create_xprt(serv, "tcp", net, PF_INET,
				nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
	if (ret <= 0)
		goto out_err;
	nn->nfs_callback_tcpport = ret;
	dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
			nn->nfs_callback_tcpport, PF_INET, net);

	ret = svc_create_xprt(serv, "tcp", net, PF_INET6,
				nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
	if (ret > 0) {
		nn->nfs_callback_tcpport6 = ret;
		dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
				nn->nfs_callback_tcpport6, PF_INET6, net);
	} else if (ret != -EAFNOSUPPORT)
		goto out_err;
	return 0;

out_err:
	return (ret) ? ret : -ENOMEM;
}

/*
 * This is the NFSv4 callback kernel thread.
 */
static int
nfs4_callback_svc(void *vrqstp)
{
	int err, preverr = 0;
	struct svc_rqst *rqstp = vrqstp;

	set_freezable();

	while (!kthread_should_stop()) {
		/*
		 * Listen for a request on the socket
		 */
		err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
		if (err == -EAGAIN || err == -EINTR) {
			preverr = err;
			continue;
		}
		if (err < 0) {
			if (err != preverr) {
				printk(KERN_WARNING "NFS: %s: unexpected error "
					"from svc_recv (%d)\n", __func__, err);
				preverr = err;
			}
			schedule_timeout_uninterruptible(HZ);
			continue;
		}
		preverr = err;
		svc_process(rqstp);
	}
	return 0;
}

/*
 * Prepare to bring up the NFSv4 callback service
 */
static struct svc_rqst *
nfs4_callback_up(struct svc_serv *serv)
{
	return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
}

#if defined(CONFIG_NFS_V4_1)
static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
{
	/*
	 * Create an svc_sock for the back channel service that shares the
	 * fore channel connection.
	 * Returns the input port (0) and sets the svc_serv bc_xprt on success
	 */
	return svc_create_xprt(serv, "tcp-bc", net, PF_INET, 0,
			      SVC_SOCK_ANONYMOUS);
}

/*
 * The callback service for NFSv4.1 callbacks
 */
static int
nfs41_callback_svc(void *vrqstp)
{
	struct svc_rqst *rqstp = vrqstp;
	struct svc_serv *serv = rqstp->rq_server;
	struct rpc_rqst *req;
	int error;
	DEFINE_WAIT(wq);

	set_freezable();

	while (!kthread_should_stop()) {
		prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
		spin_lock_bh(&serv->sv_cb_lock);
		if (!list_empty(&serv->sv_cb_list)) {
			req = list_first_entry(&serv->sv_cb_list,
					struct rpc_rqst, rq_bc_list);
			list_del(&req->rq_bc_list);
			spin_unlock_bh(&serv->sv_cb_lock);
			dprintk("Invoking bc_svc_process()\n");
			error = bc_svc_process(serv, req, rqstp);
			dprintk("bc_svc_process() returned w/ error code= %d\n",
				error);
		} else {
			spin_unlock_bh(&serv->sv_cb_lock);
			schedule();
		}
		finish_wait(&serv->sv_cb_waitq, &wq);
	}
	return 0;
}

/*
 * Bring up the NFSv4.1 callback service
 */
static struct svc_rqst *
nfs41_callback_up(struct svc_serv *serv)
{
	struct svc_rqst *rqstp;

	INIT_LIST_HEAD(&serv->sv_cb_list);
	spin_lock_init(&serv->sv_cb_lock);
	init_waitqueue_head(&serv->sv_cb_waitq);
	rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
	if (IS_ERR(rqstp)) {
		svc_xprt_put(serv->sv_bc_xprt);
		serv->sv_bc_xprt = NULL;
	}
	dprintk("--> %s return %ld\n", __func__,
		IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0);
	return rqstp;
}

static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
		struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
{
	*rqstpp = nfs41_callback_up(serv);
	*callback_svc = nfs41_callback_svc;
}

static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
		struct svc_serv *serv)
{
	if (minorversion)
		/*
		 * Save the svc_serv in the transport so that it can
		 * be referenced when the session backchannel is initialized
		 */
		xprt->bc_serv = serv;
}
#else
static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
{
	return 0;
}

static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
		struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
{
	*rqstpp = ERR_PTR(-ENOTSUPP);
	*callback_svc = ERR_PTR(-ENOTSUPP);
}

static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
		struct svc_serv *serv)
{
}
#endif /* CONFIG_NFS_V4_1 */

static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
				  struct svc_serv *serv)
{
	struct svc_rqst *rqstp;
	int (*callback_svc)(void *vrqstp);
	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	char svc_name[12];
	int ret;

	nfs_callback_bc_serv(minorversion, xprt, serv);

	if (cb_info->task)
		return 0;

	switch (minorversion) {
	case 0:
		/* v4.0 callback setup */
		rqstp = nfs4_callback_up(serv);
		callback_svc = nfs4_callback_svc;
		break;
	default:
		nfs_minorversion_callback_svc_setup(serv,
				&rqstp, &callback_svc);
	}

	if (IS_ERR(rqstp))
		return PTR_ERR(rqstp);

	svc_sock_update_bufs(serv);

	sprintf(svc_name, "nfsv4.%u-svc", minorversion);
	cb_info->serv = serv;
	cb_info->rqst = rqstp;
	cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
	if (IS_ERR(cb_info->task)) {
		ret = PTR_ERR(cb_info->task);
		svc_exit_thread(cb_info->rqst);
		cb_info->rqst = NULL;
		cb_info->task = NULL;
		return PTR_ERR(cb_info->task);
	}
	dprintk("nfs_callback_up: service started\n");
	return 0;
}

static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
{
	struct nfs_net *nn = net_generic(net, nfs_net_id);

	if (--nn->cb_users[minorversion])
		return;

	dprintk("NFS: destroy per-net callback data; net=%p\n", net);
	svc_shutdown_net(serv, net);
}

static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net)
{
	struct nfs_net *nn = net_generic(net, nfs_net_id);
	int ret;

	if (nn->cb_users[minorversion]++)
		return 0;

	dprintk("NFS: create per-net callback data; net=%p\n", net);

	ret = svc_bind(serv, net);
	if (ret < 0) {
		printk(KERN_WARNING "NFS: bind callback service failed\n");
		goto err_bind;
	}

	switch (minorversion) {
		case 0:
			ret = nfs4_callback_up_net(serv, net);
			break;
		case 1:
			ret = nfs41_callback_up_net(serv, net);
			break;
		default:
			printk(KERN_ERR "NFS: unknown callback version: %d\n",
					minorversion);
			ret = -EINVAL;
			break;
	}

	if (ret < 0) {
		printk(KERN_ERR "NFS: callback service start failed\n");
		goto err_socks;
	}
	return 0;

err_socks:
	svc_rpcb_cleanup(serv, net);
err_bind:
	dprintk("NFS: Couldn't create callback socket: err = %d; "
			"net = %p\n", ret, net);
	return ret;
}

static struct svc_serv *nfs_callback_create_svc(int minorversion)
{
	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	struct svc_serv *serv;

	/*
	 * Check whether we're already up and running.
	 */
	if (cb_info->task) {
		/*
		 * Note: increase service usage, because later in case of error
		 * svc_destroy() will be called.
		 */
		svc_get(cb_info->serv);
		return cb_info->serv;
	}

	/*
	 * Sanity check: if there's no task,
	 * we should be the first user ...
	 */
	if (cb_info->users)
		printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
			cb_info->users);

	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
	if (!serv) {
		printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
		return ERR_PTR(-ENOMEM);
	}
	/* As there is only one thread we need to over-ride the
	 * default maximum of 80 connections
	 */
	serv->sv_maxconn = 1024;
	dprintk("nfs_callback_create_svc: service created\n");
	return serv;
}

/*
 * Bring up the callback thread if it is not already up.
 */
int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
{
	struct svc_serv *serv;
	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	int ret;
	struct net *net = xprt->xprt_net;

	mutex_lock(&nfs_callback_mutex);

	serv = nfs_callback_create_svc(minorversion);
	if (IS_ERR(serv)) {
		ret = PTR_ERR(serv);
		goto err_create;
	}

	ret = nfs_callback_up_net(minorversion, serv, net);
	if (ret < 0)
		goto err_net;

	ret = nfs_callback_start_svc(minorversion, xprt, serv);
	if (ret < 0)
		goto err_start;

	cb_info->users++;
	/*
	 * svc_create creates the svc_serv with sv_nrthreads == 1, and then
	 * svc_prepare_thread increments that. So we need to call svc_destroy
	 * on both success and failure so that the refcount is 1 when the
	 * thread exits.
	 */
err_net:
	svc_destroy(serv);
err_create:
	mutex_unlock(&nfs_callback_mutex);
	return ret;

err_start:
	nfs_callback_down_net(minorversion, serv, net);
	dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
	goto err_net;
}

/*
 * Kill the callback thread if it's no longer being used.
 */
void nfs_callback_down(int minorversion, struct net *net)
{
	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];

	mutex_lock(&nfs_callback_mutex);
	nfs_callback_down_net(minorversion, cb_info->serv, net);
	cb_info->users--;
	if (cb_info->users == 0 && cb_info->task != NULL) {
		kthread_stop(cb_info->task);
		dprintk("nfs_callback_down: service stopped\n");
		svc_exit_thread(cb_info->rqst);
		dprintk("nfs_callback_down: service destroyed\n");
		cb_info->serv = NULL;
		cb_info->rqst = NULL;
		cb_info->task = NULL;
	}
	mutex_unlock(&nfs_callback_mutex);
}

/* Boolean check of RPC_AUTH_GSS principal */
int
check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
{
	char *p = rqstp->rq_cred.cr_principal;

	if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
		return 1;

	/* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
	if (clp->cl_minorversion != 0)
		return 0;
	/*
	 * It might just be a normal user principal, in which case
	 * userspace won't bother to tell us the name at all.
	 */
	if (p == NULL)
		return 0;

	/* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */

	if (memcmp(p, "nfs@", 4) != 0)
		return 0;
	p += 4;
	if (strcmp(p, clp->cl_hostname) != 0)
		return 0;
	return 1;
}

/*
 * pg_authenticate method for nfsv4 callback threads.
 *
 * The authflavor has been negotiated, so an incorrect flavor is a server
 * bug. Drop packets with incorrect authflavor.
 *
 * All other checking done after NFS decoding where the nfs_client can be
 * found in nfs4_callback_compound
 */
static int nfs_callback_authenticate(struct svc_rqst *rqstp)
{
	switch (rqstp->rq_authop->flavour) {
	case RPC_AUTH_NULL:
		if (rqstp->rq_proc != CB_NULL)
			return SVC_DROP;
		break;
	case RPC_AUTH_GSS:
		/* No RPC_AUTH_GSS support yet in NFSv4.1 */
		 if (svc_is_backchannel(rqstp))
			return SVC_DROP;
	}
	return SVC_OK;
}

/*
 * Define NFS4 callback program
 */
static struct svc_version *nfs4_callback_version[] = {
	[1] = &nfs4_callback_version1,
	[4] = &nfs4_callback_version4,
};

static struct svc_stat nfs4_callback_stats;

static struct svc_program nfs4_callback_program = {
	.pg_prog = NFS4_CALLBACK,			/* RPC service number */
	.pg_nvers = ARRAY_SIZE(nfs4_callback_version),	/* Number of entries */
	.pg_vers = nfs4_callback_version,		/* version table */
	.pg_name = "NFSv4 callback",			/* service name */
	.pg_class = "nfs",				/* authentication class */
	.pg_stats = &nfs4_callback_stats,
	.pg_authenticate = nfs_callback_authenticate,
};
Commit	Line	Data
	1	/*
	2	* linux/fs/nfs/callback.c
	3	*
	4	* Copyright (C) 2004 Trond Myklebust
	5	*
	6	* NFSv4 callback handling
	7	*/
	8
	9	#include <linux/completion.h>
	10	#include <linux/ip.h>
	11	#include <linux/module.h>
	12	#include <linux/sunrpc/svc.h>
	13	#include <linux/sunrpc/svcsock.h>
	14	#include <linux/nfs_fs.h>
	15	#include <linux/errno.h>
	16	#include <linux/mutex.h>
	17	#include <linux/freezer.h>
	18	#include <linux/kthread.h>
	19	#include <linux/sunrpc/svcauth_gss.h>
	20	#include <linux/sunrpc/bc_xprt.h>
	21
	22	#include <net/inet_sock.h>
	23
	24	#include "nfs4_fs.h"
	25	#include "callback.h"
	26	#include "internal.h"
	27	#include "netns.h"
	28
	29	#define NFSDBG_FACILITY NFSDBG_CALLBACK
	30
	31	struct nfs_callback_data {
	32	unsigned int users;
	33	struct svc_serv *serv;
	34	struct svc_rqst *rqst;
	35	struct task_struct *task;
	36	};
	37
	38	static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
	39	static DEFINE_MUTEX(nfs_callback_mutex);
	40	static struct svc_program nfs4_callback_program;
	41
	42	static int nfs4_callback_up_net(struct svc_serv serv, struct net net)
	43	{
	44	int ret;
	45	struct nfs_net *nn = net_generic(net, nfs_net_id);
	46
	47	ret = svc_create_xprt(serv, "tcp", net, PF_INET,
	48	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
	49	if (ret <= 0)
	50	goto out_err;
	51	nn->nfs_callback_tcpport = ret;
	52	dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
	53	nn->nfs_callback_tcpport, PF_INET, net);
	54
	55	ret = svc_create_xprt(serv, "tcp", net, PF_INET6,
	56	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
	57	if (ret > 0) {
	58	nn->nfs_callback_tcpport6 = ret;
	59	dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
	60	nn->nfs_callback_tcpport6, PF_INET6, net);
	61	} else if (ret != -EAFNOSUPPORT)
	62	goto out_err;
	63	return 0;
	64
	65	out_err:
	66	return (ret) ? ret : -ENOMEM;
	67	}
	68
	69	/*
	70	* This is the NFSv4 callback kernel thread.
	71	*/
	72	static int
	73	nfs4_callback_svc(void *vrqstp)
	74	{
	75	int err, preverr = 0;
	76	struct svc_rqst *rqstp = vrqstp;
	77
	78	set_freezable();
	79
	80	while (!kthread_should_stop()) {
	81	/*
	82	* Listen for a request on the socket
	83	*/
	84	err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
	85	if (err == -EAGAIN \|\| err == -EINTR) {
	86	preverr = err;
	87	continue;
	88	}
	89	if (err < 0) {
	90	if (err != preverr) {
	91	printk(KERN_WARNING "NFS: %s: unexpected error "
	92	"from svc_recv (%d)\n", __func__, err);
	93	preverr = err;
	94	}
	95	schedule_timeout_uninterruptible(HZ);
	96	continue;
	97	}
	98	preverr = err;
	99	svc_process(rqstp);
	100	}
	101	return 0;
	102	}
	103
	104	/*
	105	* Prepare to bring up the NFSv4 callback service
	106	*/
	107	static struct svc_rqst *
	108	nfs4_callback_up(struct svc_serv *serv)
	109	{
	110	return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
	111	}
	112
	113	#if defined(CONFIG_NFS_V4_1)
	114	static int nfs41_callback_up_net(struct svc_serv serv, struct net net)
	115	{
	116	/*
	117	* Create an svc_sock for the back channel service that shares the
	118	* fore channel connection.
	119	* Returns the input port (0) and sets the svc_serv bc_xprt on success
	120	*/
	121	return svc_create_xprt(serv, "tcp-bc", net, PF_INET, 0,
	122	SVC_SOCK_ANONYMOUS);
	123	}
	124
	125	/*
	126	* The callback service for NFSv4.1 callbacks
	127	*/
	128	static int
	129	nfs41_callback_svc(void *vrqstp)
	130	{
	131	struct svc_rqst *rqstp = vrqstp;
	132	struct svc_serv *serv = rqstp->rq_server;
	133	struct rpc_rqst *req;
	134	int error;
	135	DEFINE_WAIT(wq);
	136
	137	set_freezable();
	138
	139	while (!kthread_should_stop()) {
	140	prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
	141	spin_lock_bh(&serv->sv_cb_lock);
	142	if (!list_empty(&serv->sv_cb_list)) {
	143	req = list_first_entry(&serv->sv_cb_list,
	144	struct rpc_rqst, rq_bc_list);
	145	list_del(&req->rq_bc_list);
	146	spin_unlock_bh(&serv->sv_cb_lock);
	147	dprintk("Invoking bc_svc_process()\n");
	148	error = bc_svc_process(serv, req, rqstp);
	149	dprintk("bc_svc_process() returned w/ error code= %d\n",
	150	error);
	151	} else {
	152	spin_unlock_bh(&serv->sv_cb_lock);
	153	schedule();
	154	}
	155	finish_wait(&serv->sv_cb_waitq, &wq);
	156	}
	157	return 0;
	158	}
	159
	160	/*
	161	* Bring up the NFSv4.1 callback service
	162	*/
	163	static struct svc_rqst *
	164	nfs41_callback_up(struct svc_serv *serv)
	165	{
	166	struct svc_rqst *rqstp;
	167
	168	INIT_LIST_HEAD(&serv->sv_cb_list);
	169	spin_lock_init(&serv->sv_cb_lock);
	170	init_waitqueue_head(&serv->sv_cb_waitq);
	171	rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
	172	if (IS_ERR(rqstp)) {
	173	svc_xprt_put(serv->sv_bc_xprt);
	174	serv->sv_bc_xprt = NULL;
	175	}
	176	dprintk("--> %s return %ld\n", __func__,
	177	IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0);
	178	return rqstp;
	179	}
	180
	181	static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
	182	struct svc_rqst rqstpp, int (callback_svc)(void *vrqstp))
	183	{
	184	*rqstpp = nfs41_callback_up(serv);
	185	*callback_svc = nfs41_callback_svc;
	186	}
	187
	188	static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
	189	struct svc_serv *serv)
	190	{
	191	if (minorversion)
	192	/*
	193	* Save the svc_serv in the transport so that it can
	194	* be referenced when the session backchannel is initialized
	195	*/
	196	xprt->bc_serv = serv;
	197	}
	198	#else
	199	static int nfs41_callback_up_net(struct svc_serv serv, struct net net)
	200	{
	201	return 0;
	202	}
	203
	204	static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
	205	struct svc_rqst rqstpp, int (callback_svc)(void *vrqstp))
	206	{
	207	*rqstpp = ERR_PTR(-ENOTSUPP);
	208	*callback_svc = ERR_PTR(-ENOTSUPP);
	209	}
	210
	211	static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
	212	struct svc_serv *serv)
	213	{
	214	}
	215	#endif /* CONFIG_NFS_V4_1 */
	216
	217	static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
	218	struct svc_serv *serv)
	219	{
	220	struct svc_rqst *rqstp;
	221	int (callback_svc)(void vrqstp);
	222	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	223	char svc_name[12];
	224	int ret;
	225
	226	nfs_callback_bc_serv(minorversion, xprt, serv);
	227
	228	if (cb_info->task)
	229	return 0;
	230
	231	switch (minorversion) {
	232	case 0:
	233	/* v4.0 callback setup */
	234	rqstp = nfs4_callback_up(serv);
	235	callback_svc = nfs4_callback_svc;
	236	break;
	237	default:
	238	nfs_minorversion_callback_svc_setup(serv,
	239	&rqstp, &callback_svc);
	240	}
	241
	242	if (IS_ERR(rqstp))
	243	return PTR_ERR(rqstp);
	244
	245	svc_sock_update_bufs(serv);
	246
	247	sprintf(svc_name, "nfsv4.%u-svc", minorversion);
	248	cb_info->serv = serv;
	249	cb_info->rqst = rqstp;
	250	cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
	251	if (IS_ERR(cb_info->task)) {
	252	ret = PTR_ERR(cb_info->task);
	253	svc_exit_thread(cb_info->rqst);
	254	cb_info->rqst = NULL;
	255	cb_info->task = NULL;
	256	return PTR_ERR(cb_info->task);
	257	}
	258	dprintk("nfs_callback_up: service started\n");
	259	return 0;
	260	}
	261
	262	static void nfs_callback_down_net(u32 minorversion, struct svc_serv serv, struct net net)
	263	{
	264	struct nfs_net *nn = net_generic(net, nfs_net_id);
	265
	266	if (--nn->cb_users[minorversion])
	267	return;
	268
	269	dprintk("NFS: destroy per-net callback data; net=%p\n", net);
	270	svc_shutdown_net(serv, net);
	271	}
	272
	273	static int nfs_callback_up_net(int minorversion, struct svc_serv serv, struct net net)
	274	{
	275	struct nfs_net *nn = net_generic(net, nfs_net_id);
	276	int ret;
	277
	278	if (nn->cb_users[minorversion]++)
	279	return 0;
	280
	281	dprintk("NFS: create per-net callback data; net=%p\n", net);
	282
	283	ret = svc_bind(serv, net);
	284	if (ret < 0) {
	285	printk(KERN_WARNING "NFS: bind callback service failed\n");
	286	goto err_bind;
	287	}
	288
	289	switch (minorversion) {
	290	case 0:
	291	ret = nfs4_callback_up_net(serv, net);
	292	break;
	293	case 1:
	294	ret = nfs41_callback_up_net(serv, net);
	295	break;
	296	default:
	297	printk(KERN_ERR "NFS: unknown callback version: %d\n",
	298	minorversion);
	299	ret = -EINVAL;
	300	break;
	301	}
	302
	303	if (ret < 0) {
	304	printk(KERN_ERR "NFS: callback service start failed\n");
	305	goto err_socks;
	306	}
	307	return 0;
	308
	309	err_socks:
	310	svc_rpcb_cleanup(serv, net);
	311	err_bind:
	312	dprintk("NFS: Couldn't create callback socket: err = %d; "
	313	"net = %p\n", ret, net);
	314	return ret;
	315	}
	316
	317	static struct svc_serv *nfs_callback_create_svc(int minorversion)
	318	{
	319	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	320	struct svc_serv *serv;
	321
	322	/*
	323	* Check whether we're already up and running.
	324	*/
	325	if (cb_info->task) {
	326	/*
	327	* Note: increase service usage, because later in case of error
	328	* svc_destroy() will be called.
	329	*/
	330	svc_get(cb_info->serv);
	331	return cb_info->serv;
	332	}
	333
	334	/*
	335	* Sanity check: if there's no task,
	336	* we should be the first user ...
	337	*/
	338	if (cb_info->users)
	339	printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
	340	cb_info->users);
	341
	342	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
	343	if (!serv) {
	344	printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
	345	return ERR_PTR(-ENOMEM);
	346	}
	347	/* As there is only one thread we need to over-ride the
	348	* default maximum of 80 connections
	349	*/
	350	serv->sv_maxconn = 1024;
	351	dprintk("nfs_callback_create_svc: service created\n");
	352	return serv;
	353	}
	354
	355	/*
	356	* Bring up the callback thread if it is not already up.
	357	*/
	358	int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
	359	{
	360	struct svc_serv *serv;
	361	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	362	int ret;
	363	struct net *net = xprt->xprt_net;
	364
	365	mutex_lock(&nfs_callback_mutex);
	366
	367	serv = nfs_callback_create_svc(minorversion);
	368	if (IS_ERR(serv)) {
	369	ret = PTR_ERR(serv);
	370	goto err_create;
	371	}
	372
	373	ret = nfs_callback_up_net(minorversion, serv, net);
	374	if (ret < 0)
	375	goto err_net;
	376
	377	ret = nfs_callback_start_svc(minorversion, xprt, serv);
	378	if (ret < 0)
	379	goto err_start;
	380
	381	cb_info->users++;
	382	/*
	383	* svc_create creates the svc_serv with sv_nrthreads == 1, and then
	384	* svc_prepare_thread increments that. So we need to call svc_destroy
	385	* on both success and failure so that the refcount is 1 when the
	386	* thread exits.
	387	*/
	388	err_net:
	389	svc_destroy(serv);
	390	err_create:
	391	mutex_unlock(&nfs_callback_mutex);
	392	return ret;
	393
	394	err_start:
	395	nfs_callback_down_net(minorversion, serv, net);
	396	dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
	397	goto err_net;
	398	}
	399
	400	/*
	401	* Kill the callback thread if it's no longer being used.
	402	*/
	403	void nfs_callback_down(int minorversion, struct net *net)
	404	{
	405	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	406
	407	mutex_lock(&nfs_callback_mutex);
	408	nfs_callback_down_net(minorversion, cb_info->serv, net);
	409	cb_info->users--;
	410	if (cb_info->users == 0 && cb_info->task != NULL) {
	411	kthread_stop(cb_info->task);
	412	dprintk("nfs_callback_down: service stopped\n");
	413	svc_exit_thread(cb_info->rqst);
	414	dprintk("nfs_callback_down: service destroyed\n");
	415	cb_info->serv = NULL;
	416	cb_info->rqst = NULL;
	417	cb_info->task = NULL;
	418	}
	419	mutex_unlock(&nfs_callback_mutex);
	420	}
	421
	422	/* Boolean check of RPC_AUTH_GSS principal */
	423	int
	424	check_gss_callback_principal(struct nfs_client clp, struct svc_rqst rqstp)
	425	{
	426	char *p = rqstp->rq_cred.cr_principal;
	427
	428	if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
	429	return 1;
	430
	431	/* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
	432	if (clp->cl_minorversion != 0)
	433	return 0;
	434	/*
	435	* It might just be a normal user principal, in which case
	436	* userspace won't bother to tell us the name at all.
	437	*/
	438	if (p == NULL)
	439	return 0;
	440
	441	/* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
	442
	443	if (memcmp(p, "nfs@", 4) != 0)
	444	return 0;
	445	p += 4;
	446	if (strcmp(p, clp->cl_hostname) != 0)
	447	return 0;
	448	return 1;
	449	}
	450
	451	/*
	452	* pg_authenticate method for nfsv4 callback threads.
	453	*
	454	* The authflavor has been negotiated, so an incorrect flavor is a server
	455	* bug. Drop packets with incorrect authflavor.
	456	*
	457	* All other checking done after NFS decoding where the nfs_client can be
	458	* found in nfs4_callback_compound
	459	*/
	460	static int nfs_callback_authenticate(struct svc_rqst *rqstp)
	461	{
	462	switch (rqstp->rq_authop->flavour) {
	463	case RPC_AUTH_NULL:
	464	if (rqstp->rq_proc != CB_NULL)
	465	return SVC_DROP;
	466	break;
	467	case RPC_AUTH_GSS:
	468	/* No RPC_AUTH_GSS support yet in NFSv4.1 */
	469	if (svc_is_backchannel(rqstp))
	470	return SVC_DROP;
	471	}
	472	return SVC_OK;
	473	}
	474
	475	/*
	476	* Define NFS4 callback program
	477	*/
	478	static struct svc_version *nfs4_callback_version[] = {
	479	[1] = &nfs4_callback_version1,
	480	[4] = &nfs4_callback_version4,
	481	};
	482
	483	static struct svc_stat nfs4_callback_stats;
	484
	485	static struct svc_program nfs4_callback_program = {
	486	.pg_prog = NFS4_CALLBACK, /* RPC service number */
	487	.pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
	488	.pg_vers = nfs4_callback_version, /* version table */
	489	.pg_name = "NFSv4 callback", /* service name */
	490	.pg_class = "nfs", /* authentication class */
	491	.pg_stats = &nfs4_callback_stats,
	492	.pg_authenticate = nfs_callback_authenticate,
	493	};