[linux-block.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/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 inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
		struct svc_serv *serv,
		struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
{
	if (minorversion) {
		*rqstpp = nfs41_callback_up(serv);
		*callback_svc = nfs41_callback_svc;
	}
	return minorversion;
}

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 inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
		struct svc_serv *serv,
		struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
{
	return 0;
}

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;
	int minorversion_setup;

	nfs_callback_bc_serv(minorversion, xprt, serv);

	if (cb_info->task)
		return 0;

	minorversion_setup =  nfs_minorversion_callback_svc_setup(minorversion,
					serv, &rqstp, &callback_svc);
	if (!minorversion_setup) {
		/* v4.0 callback setup */
		rqstp = nfs4_callback_up(serv);
		callback_svc = nfs4_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);
		svc_exit_thread(cb_info->rqst);
		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/mutex.h>
	16	#include <linux/freezer.h>
	17	#include <linux/kthread.h>
	18	#include <linux/sunrpc/svcauth_gss.h>
	19	#include <linux/sunrpc/bc_xprt.h>
	20
	21	#include <net/inet_sock.h>
	22
	23	#include "nfs4_fs.h"
	24	#include "callback.h"
	25	#include "internal.h"
	26	#include "netns.h"
	27
	28	#define NFSDBG_FACILITY NFSDBG_CALLBACK
	29
	30	struct nfs_callback_data {
	31	unsigned int users;
	32	struct svc_serv *serv;
	33	struct svc_rqst *rqst;
	34	struct task_struct *task;
	35	};
	36
	37	static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
	38	static DEFINE_MUTEX(nfs_callback_mutex);
	39	static struct svc_program nfs4_callback_program;
	40
	41	static int nfs4_callback_up_net(struct svc_serv serv, struct net net)
	42	{
	43	int ret;
	44	struct nfs_net *nn = net_generic(net, nfs_net_id);
	45
	46	ret = svc_create_xprt(serv, "tcp", net, PF_INET,
	47	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
	48	if (ret <= 0)
	49	goto out_err;
	50	nn->nfs_callback_tcpport = ret;
	51	dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
	52	nn->nfs_callback_tcpport, PF_INET, net);
	53
	54	ret = svc_create_xprt(serv, "tcp", net, PF_INET6,
	55	nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
	56	if (ret > 0) {
	57	nn->nfs_callback_tcpport6 = ret;
	58	dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
	59	nn->nfs_callback_tcpport6, PF_INET6, net);
	60	} else if (ret != -EAFNOSUPPORT)
	61	goto out_err;
	62	return 0;
	63
	64	out_err:
	65	return (ret) ? ret : -ENOMEM;
	66	}
	67
	68	/*
	69	* This is the NFSv4 callback kernel thread.
	70	*/
	71	static int
	72	nfs4_callback_svc(void *vrqstp)
	73	{
	74	int err, preverr = 0;
	75	struct svc_rqst *rqstp = vrqstp;
	76
	77	set_freezable();
	78
	79	while (!kthread_should_stop()) {
	80	/*
	81	* Listen for a request on the socket
	82	*/
	83	err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
	84	if (err == -EAGAIN \|\| err == -EINTR) {
	85	preverr = err;
	86	continue;
	87	}
	88	if (err < 0) {
	89	if (err != preverr) {
	90	printk(KERN_WARNING "NFS: %s: unexpected error "
	91	"from svc_recv (%d)\n", __func__, err);
	92	preverr = err;
	93	}
	94	schedule_timeout_uninterruptible(HZ);
	95	continue;
	96	}
	97	preverr = err;
	98	svc_process(rqstp);
	99	}
	100	return 0;
	101	}
	102
	103	/*
	104	* Prepare to bring up the NFSv4 callback service
	105	*/
	106	static struct svc_rqst *
	107	nfs4_callback_up(struct svc_serv *serv)
	108	{
	109	return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
	110	}
	111
	112	#if defined(CONFIG_NFS_V4_1)
	113	static int nfs41_callback_up_net(struct svc_serv serv, struct net net)
	114	{
	115	/*
	116	* Create an svc_sock for the back channel service that shares the
	117	* fore channel connection.
	118	* Returns the input port (0) and sets the svc_serv bc_xprt on success
	119	*/
	120	return svc_create_xprt(serv, "tcp-bc", net, PF_INET, 0,
	121	SVC_SOCK_ANONYMOUS);
	122	}
	123
	124	/*
	125	* The callback service for NFSv4.1 callbacks
	126	*/
	127	static int
	128	nfs41_callback_svc(void *vrqstp)
	129	{
	130	struct svc_rqst *rqstp = vrqstp;
	131	struct svc_serv *serv = rqstp->rq_server;
	132	struct rpc_rqst *req;
	133	int error;
	134	DEFINE_WAIT(wq);
	135
	136	set_freezable();
	137
	138	while (!kthread_should_stop()) {
	139	prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
	140	spin_lock_bh(&serv->sv_cb_lock);
	141	if (!list_empty(&serv->sv_cb_list)) {
	142	req = list_first_entry(&serv->sv_cb_list,
	143	struct rpc_rqst, rq_bc_list);
	144	list_del(&req->rq_bc_list);
	145	spin_unlock_bh(&serv->sv_cb_lock);
	146	dprintk("Invoking bc_svc_process()\n");
	147	error = bc_svc_process(serv, req, rqstp);
	148	dprintk("bc_svc_process() returned w/ error code= %d\n",
	149	error);
	150	} else {
	151	spin_unlock_bh(&serv->sv_cb_lock);
	152	schedule();
	153	}
	154	finish_wait(&serv->sv_cb_waitq, &wq);
	155	}
	156	return 0;
	157	}
	158
	159	/*
	160	* Bring up the NFSv4.1 callback service
	161	*/
	162	static struct svc_rqst *
	163	nfs41_callback_up(struct svc_serv *serv)
	164	{
	165	struct svc_rqst *rqstp;
	166
	167	INIT_LIST_HEAD(&serv->sv_cb_list);
	168	spin_lock_init(&serv->sv_cb_lock);
	169	init_waitqueue_head(&serv->sv_cb_waitq);
	170	rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
	171	if (IS_ERR(rqstp)) {
	172	svc_xprt_put(serv->sv_bc_xprt);
	173	serv->sv_bc_xprt = NULL;
	174	}
	175	dprintk("--> %s return %ld\n", __func__,
	176	IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0);
	177	return rqstp;
	178	}
	179
	180	static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
	181	struct svc_serv *serv,
	182	struct svc_rqst rqstpp, int (callback_svc)(void *vrqstp))
	183	{
	184	if (minorversion) {
	185	*rqstpp = nfs41_callback_up(serv);
	186	*callback_svc = nfs41_callback_svc;
	187	}
	188	return minorversion;
	189	}
	190
	191	static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
	192	struct svc_serv *serv)
	193	{
	194	if (minorversion)
	195	/*
	196	* Save the svc_serv in the transport so that it can
	197	* be referenced when the session backchannel is initialized
	198	*/
	199	xprt->bc_serv = serv;
	200	}
	201	#else
	202	static int nfs41_callback_up_net(struct svc_serv serv, struct net net)
	203	{
	204	return 0;
	205	}
	206
	207	static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
	208	struct svc_serv *serv,
	209	struct svc_rqst rqstpp, int (callback_svc)(void *vrqstp))
	210	{
	211	return 0;
	212	}
	213
	214	static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
	215	struct svc_serv *serv)
	216	{
	217	}
	218	#endif /* CONFIG_NFS_V4_1 */
	219
	220	static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
	221	struct svc_serv *serv)
	222	{
	223	struct svc_rqst *rqstp;
	224	int (callback_svc)(void vrqstp);
	225	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	226	char svc_name[12];
	227	int ret;
	228	int minorversion_setup;
	229
	230	nfs_callback_bc_serv(minorversion, xprt, serv);
	231
	232	if (cb_info->task)
	233	return 0;
	234
	235	minorversion_setup = nfs_minorversion_callback_svc_setup(minorversion,
	236	serv, &rqstp, &callback_svc);
	237	if (!minorversion_setup) {
	238	/* v4.0 callback setup */
	239	rqstp = nfs4_callback_up(serv);
	240	callback_svc = nfs4_callback_svc;
	241	}
	242
	243	if (IS_ERR(rqstp))
	244	return PTR_ERR(rqstp);
	245
	246	svc_sock_update_bufs(serv);
	247
	248	sprintf(svc_name, "nfsv4.%u-svc", minorversion);
	249	cb_info->serv = serv;
	250	cb_info->rqst = rqstp;
	251	cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
	252	if (IS_ERR(cb_info->task)) {
	253	ret = PTR_ERR(cb_info->task);
	254	svc_exit_thread(cb_info->rqst);
	255	cb_info->rqst = NULL;
	256	cb_info->task = NULL;
	257	return PTR_ERR(cb_info->task);
	258	}
	259	dprintk("nfs_callback_up: service started\n");
	260	return 0;
	261	}
	262
	263	static void nfs_callback_down_net(u32 minorversion, struct svc_serv serv, struct net net)
	264	{
	265	struct nfs_net *nn = net_generic(net, nfs_net_id);
	266
	267	if (--nn->cb_users[minorversion])
	268	return;
	269
	270	dprintk("NFS: destroy per-net callback data; net=%p\n", net);
	271	svc_shutdown_net(serv, net);
	272	}
	273
	274	static int nfs_callback_up_net(int minorversion, struct svc_serv serv, struct net net)
	275	{
	276	struct nfs_net *nn = net_generic(net, nfs_net_id);
	277	int ret;
	278
	279	if (nn->cb_users[minorversion]++)
	280	return 0;
	281
	282	dprintk("NFS: create per-net callback data; net=%p\n", net);
	283
	284	ret = svc_bind(serv, net);
	285	if (ret < 0) {
	286	printk(KERN_WARNING "NFS: bind callback service failed\n");
	287	goto err_bind;
	288	}
	289
	290	switch (minorversion) {
	291	case 0:
	292	ret = nfs4_callback_up_net(serv, net);
	293	break;
	294	case 1:
	295	ret = nfs41_callback_up_net(serv, net);
	296	break;
	297	default:
	298	printk(KERN_ERR "NFS: unknown callback version: %d\n",
	299	minorversion);
	300	ret = -EINVAL;
	301	break;
	302	}
	303
	304	if (ret < 0) {
	305	printk(KERN_ERR "NFS: callback service start failed\n");
	306	goto err_socks;
	307	}
	308	return 0;
	309
	310	err_socks:
	311	svc_rpcb_cleanup(serv, net);
	312	err_bind:
	313	dprintk("NFS: Couldn't create callback socket: err = %d; "
	314	"net = %p\n", ret, net);
	315	return ret;
	316	}
	317
	318	static struct svc_serv *nfs_callback_create_svc(int minorversion)
	319	{
	320	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	321	struct svc_serv *serv;
	322
	323	/*
	324	* Check whether we're already up and running.
	325	*/
	326	if (cb_info->task) {
	327	/*
	328	* Note: increase service usage, because later in case of error
	329	* svc_destroy() will be called.
	330	*/
	331	svc_get(cb_info->serv);
	332	return cb_info->serv;
	333	}
	334
	335	/*
	336	* Sanity check: if there's no task,
	337	* we should be the first user ...
	338	*/
	339	if (cb_info->users)
	340	printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
	341	cb_info->users);
	342
	343	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
	344	if (!serv) {
	345	printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
	346	return ERR_PTR(-ENOMEM);
	347	}
	348	/* As there is only one thread we need to over-ride the
	349	* default maximum of 80 connections
	350	*/
	351	serv->sv_maxconn = 1024;
	352	dprintk("nfs_callback_create_svc: service created\n");
	353	return serv;
	354	}
	355
	356	/*
	357	* Bring up the callback thread if it is not already up.
	358	*/
	359	int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
	360	{
	361	struct svc_serv *serv;
	362	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	363	int ret;
	364	struct net *net = xprt->xprt_net;
	365
	366	mutex_lock(&nfs_callback_mutex);
	367
	368	serv = nfs_callback_create_svc(minorversion);
	369	if (IS_ERR(serv)) {
	370	ret = PTR_ERR(serv);
	371	goto err_create;
	372	}
	373
	374	ret = nfs_callback_up_net(minorversion, serv, net);
	375	if (ret < 0)
	376	goto err_net;
	377
	378	ret = nfs_callback_start_svc(minorversion, xprt, serv);
	379	if (ret < 0)
	380	goto err_start;
	381
	382	cb_info->users++;
	383	/*
	384	* svc_create creates the svc_serv with sv_nrthreads == 1, and then
	385	* svc_prepare_thread increments that. So we need to call svc_destroy
	386	* on both success and failure so that the refcount is 1 when the
	387	* thread exits.
	388	*/
	389	err_net:
	390	svc_destroy(serv);
	391	err_create:
	392	mutex_unlock(&nfs_callback_mutex);
	393	return ret;
	394
	395	err_start:
	396	nfs_callback_down_net(minorversion, serv, net);
	397	dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
	398	goto err_net;
	399	}
	400
	401	/*
	402	* Kill the callback thread if it's no longer being used.
	403	*/
	404	void nfs_callback_down(int minorversion, struct net *net)
	405	{
	406	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
	407
	408	mutex_lock(&nfs_callback_mutex);
	409	nfs_callback_down_net(minorversion, cb_info->serv, net);
	410	cb_info->users--;
	411	if (cb_info->users == 0 && cb_info->task != NULL) {
	412	kthread_stop(cb_info->task);
	413	svc_exit_thread(cb_info->rqst);
	414	cb_info->serv = NULL;
	415	cb_info->rqst = NULL;
	416	cb_info->task = NULL;
	417	}
	418	mutex_unlock(&nfs_callback_mutex);
	419	}
	420
	421	/* Boolean check of RPC_AUTH_GSS principal */
	422	int
	423	check_gss_callback_principal(struct nfs_client clp, struct svc_rqst rqstp)
	424	{
	425	char *p = rqstp->rq_cred.cr_principal;
	426
	427	if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
	428	return 1;
	429
	430	/* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
	431	if (clp->cl_minorversion != 0)
	432	return 0;
	433	/*
	434	* It might just be a normal user principal, in which case
	435	* userspace won't bother to tell us the name at all.
	436	*/
	437	if (p == NULL)
	438	return 0;
	439
	440	/* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
	441
	442	if (memcmp(p, "nfs@", 4) != 0)
	443	return 0;
	444	p += 4;
	445	if (strcmp(p, clp->cl_hostname) != 0)
	446	return 0;
	447	return 1;
	448	}
	449
	450	/*
	451	* pg_authenticate method for nfsv4 callback threads.
	452	*
	453	* The authflavor has been negotiated, so an incorrect flavor is a server
	454	* bug. Drop packets with incorrect authflavor.
	455	*
	456	* All other checking done after NFS decoding where the nfs_client can be
	457	* found in nfs4_callback_compound
	458	*/
	459	static int nfs_callback_authenticate(struct svc_rqst *rqstp)
	460	{
	461	switch (rqstp->rq_authop->flavour) {
	462	case RPC_AUTH_NULL:
	463	if (rqstp->rq_proc != CB_NULL)
	464	return SVC_DROP;
	465	break;
	466	case RPC_AUTH_GSS:
	467	/* No RPC_AUTH_GSS support yet in NFSv4.1 */
	468	if (svc_is_backchannel(rqstp))
	469	return SVC_DROP;
	470	}
	471	return SVC_OK;
	472	}
	473
	474	/*
	475	* Define NFS4 callback program
	476	*/
	477	static struct svc_version *nfs4_callback_version[] = {
	478	[1] = &nfs4_callback_version1,
	479	[4] = &nfs4_callback_version4,
	480	};
	481
	482	static struct svc_stat nfs4_callback_stats;
	483
	484	static struct svc_program nfs4_callback_program = {
	485	.pg_prog = NFS4_CALLBACK, /* RPC service number */
	486	.pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
	487	.pg_vers = nfs4_callback_version, /* version table */
	488	.pg_name = "NFSv4 callback", /* service name */
	489	.pg_class = "nfs", /* authentication class */
	490	.pg_stats = &nfs4_callback_stats,
	491	.pg_authenticate = nfs_callback_authenticate,
	492	};