Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 892 insertions, 0 deletions

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
new file mode 100644
index 000000000..ad3863339
--- /dev/null
+++ b/fs/nfsd/nfssvc.c
@@ -0,0 +1,892 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Central processing for nfsd.
+ *
+ * Authors:	Olaf Kirch (okir@monad.swb.de)
+ *
+ * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/sched/signal.h>
+#include <linux/freezer.h>
+#include <linux/module.h>
+#include <linux/fs_struct.h>
+#include <linux/swap.h>
+
+#include <linux/sunrpc/stats.h>
+#include <linux/sunrpc/svcsock.h>
+#include <linux/sunrpc/svc_xprt.h>
+#include <linux/lockd/bind.h>
+#include <linux/nfsacl.h>
+#include <linux/seq_file.h>
+#include <linux/inetdevice.h>
+#include <net/addrconf.h>
+#include <net/ipv6.h>
+#include <net/net_namespace.h>
+#include "nfsd.h"
+#include "cache.h"
+#include "vfs.h"
+#include "netns.h"
+
+#define NFSDDBG_FACILITY	NFSDDBG_SVC
+
+extern struct svc_program	nfsd_program;
+static int			nfsd(void *vrqstp);
+
+/*
+ * nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and the members
+ * of the svc_serv struct. In particular, ->sv_nrthreads but also to some
+ * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt
+ *
+ * If (out side the lock) nn->nfsd_serv is non-NULL, then it must point to a
+ * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number
+ * of nfsd threads must exist and each must listed in ->sp_all_threads in each
+ * entry of ->sv_pools[].
+ *
+ * Transitions of the thread count between zero and non-zero are of particular
+ * interest since the svc_serv needs to be created and initialized at that
+ * point, or freed.
+ *
+ * Finally, the nfsd_mutex also protects some of the global variables that are
+ * accessed when nfsd starts and that are settable via the write_* routines in
+ * nfsctl.c. In particular:
+ *
+ *	user_recovery_dirname
+ *	user_lease_time
+ *	nfsd_versions
+ */
+DEFINE_MUTEX(nfsd_mutex);
+
+/*
+ * nfsd_drc_lock protects nfsd_drc_max_pages and nfsd_drc_pages_used.
+ * nfsd_drc_max_pages limits the total amount of memory available for
+ * version 4.1 DRC caches.
+ * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
+ */
+spinlock_t	nfsd_drc_lock;
+unsigned long	nfsd_drc_max_mem;
+unsigned long	nfsd_drc_mem_used;
+
+#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
+static struct svc_stat	nfsd_acl_svcstats;
+static const struct svc_version *nfsd_acl_version[] = {
+	[2] = &nfsd_acl_version2,
+	[3] = &nfsd_acl_version3,
+};
+
+#define NFSD_ACL_MINVERS            2
+#define NFSD_ACL_NRVERS		ARRAY_SIZE(nfsd_acl_version)
+static const struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];
+
+static struct svc_program	nfsd_acl_program = {
+	.pg_prog		= NFS_ACL_PROGRAM,
+	.pg_nvers		= NFSD_ACL_NRVERS,
+	.pg_vers		= nfsd_acl_versions,
+	.pg_name		= "nfsacl",
+	.pg_class		= "nfsd",
+	.pg_stats		= &nfsd_acl_svcstats,
+	.pg_authenticate	= &svc_set_client,
+};
+
+static struct svc_stat	nfsd_acl_svcstats = {
+	.program	= &nfsd_acl_program,
+};
+#endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
+
+static const struct svc_version *nfsd_version[] = {
+	[2] = &nfsd_version2,
+#if defined(CONFIG_NFSD_V3)
+	[3] = &nfsd_version3,
+#endif
+#if defined(CONFIG_NFSD_V4)
+	[4] = &nfsd_version4,
+#endif
+};
+
+#define NFSD_MINVERS    	2
+#define NFSD_NRVERS		ARRAY_SIZE(nfsd_version)
+static const struct svc_version *nfsd_versions[NFSD_NRVERS];
+
+struct svc_program		nfsd_program = {
+#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
+	.pg_next		= &nfsd_acl_program,
+#endif
+	.pg_prog		= NFS_PROGRAM,		/* program number */
+	.pg_nvers		= NFSD_NRVERS,		/* nr of entries in nfsd_version */
+	.pg_vers		= nfsd_versions,	/* version table */
+	.pg_name		= "nfsd",		/* program name */
+	.pg_class		= "nfsd",		/* authentication class */
+	.pg_stats		= &nfsd_svcstats,	/* version table */
+	.pg_authenticate	= &svc_set_client,	/* export authentication */
+
+};
+
+static bool nfsd_supported_minorversions[NFSD_SUPPORTED_MINOR_VERSION + 1] = {
+	[0] = 1,
+	[1] = 1,
+	[2] = 1,
+};
+
+int nfsd_vers(int vers, enum vers_op change)
+{
+	if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
+		return 0;
+	switch(change) {
+	case NFSD_SET:
+		nfsd_versions[vers] = nfsd_version[vers];
+#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
+		if (vers < NFSD_ACL_NRVERS)
+			nfsd_acl_versions[vers] = nfsd_acl_version[vers];
+#endif
+		break;
+	case NFSD_CLEAR:
+		nfsd_versions[vers] = NULL;
+#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
+		if (vers < NFSD_ACL_NRVERS)
+			nfsd_acl_versions[vers] = NULL;
+#endif
+		break;
+	case NFSD_TEST:
+		return nfsd_versions[vers] != NULL;
+	case NFSD_AVAIL:
+		return nfsd_version[vers] != NULL;
+	}
+	return 0;
+}
+
+static void
+nfsd_adjust_nfsd_versions4(void)
+{
+	unsigned i;
+
+	for (i = 0; i <= NFSD_SUPPORTED_MINOR_VERSION; i++) {
+		if (nfsd_supported_minorversions[i])
+			return;
+	}
+	nfsd_vers(4, NFSD_CLEAR);
+}
+
+int nfsd_minorversion(u32 minorversion, enum vers_op change)
+{
+	if (minorversion > NFSD_SUPPORTED_MINOR_VERSION &&
+	    change != NFSD_AVAIL)
+		return -1;
+	switch(change) {
+	case NFSD_SET:
+		nfsd_supported_minorversions[minorversion] = true;
+		nfsd_vers(4, NFSD_SET);
+		break;
+	case NFSD_CLEAR:
+		nfsd_supported_minorversions[minorversion] = false;
+		nfsd_adjust_nfsd_versions4();
+		break;
+	case NFSD_TEST:
+		return nfsd_supported_minorversions[minorversion];
+	case NFSD_AVAIL:
+		return minorversion <= NFSD_SUPPORTED_MINOR_VERSION;
+	}
+	return 0;
+}
+
+/*
+ * Maximum number of nfsd processes
+ */
+#define	NFSD_MAXSERVS		8192
+
+int nfsd_nrthreads(struct net *net)
+{
+	int rv = 0;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	mutex_lock(&nfsd_mutex);
+	if (nn->nfsd_serv)
+		rv = nn->nfsd_serv->sv_nrthreads;
+	mutex_unlock(&nfsd_mutex);
+	return rv;
+}
+
+static int nfsd_init_socks(struct net *net)
+{
+	int error;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	if (!list_empty(&nn->nfsd_serv->sv_permsocks))
+		return 0;
+
+	error = svc_create_xprt(nn->nfsd_serv, "udp", net, PF_INET, NFS_PORT,
+					SVC_SOCK_DEFAULTS);
+	if (error < 0)
+		return error;
+
+	error = svc_create_xprt(nn->nfsd_serv, "tcp", net, PF_INET, NFS_PORT,
+					SVC_SOCK_DEFAULTS);
+	if (error < 0)
+		return error;
+
+	return 0;
+}
+
+static int nfsd_users = 0;
+
+static int nfsd_startup_generic(int nrservs)
+{
+	int ret;
+
+	if (nfsd_users++)
+		return 0;
+
+	/*
+	 * Readahead param cache - will no-op if it already exists.
+	 * (Note therefore results will be suboptimal if number of
+	 * threads is modified after nfsd start.)
+	 */
+	ret = nfsd_racache_init(2*nrservs);
+	if (ret)
+		goto dec_users;
+
+	ret = nfs4_state_start();
+	if (ret)
+		goto out_racache;
+	return 0;
+
+out_racache:
+	nfsd_racache_shutdown();
+dec_users:
+	nfsd_users--;
+	return ret;
+}
+
+static void nfsd_shutdown_generic(void)
+{
+	if (--nfsd_users)
+		return;
+
+	nfs4_state_shutdown();
+	nfsd_racache_shutdown();
+}
+
+static bool nfsd_needs_lockd(void)
+{
+#if defined(CONFIG_NFSD_V3)
+	return (nfsd_versions[2] != NULL) || (nfsd_versions[3] != NULL);
+#else
+	return (nfsd_versions[2] != NULL);
+#endif
+}
+
+static int nfsd_startup_net(int nrservs, struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	int ret;
+
+	if (nn->nfsd_net_up)
+		return 0;
+
+	ret = nfsd_startup_generic(nrservs);
+	if (ret)
+		return ret;
+	ret = nfsd_init_socks(net);
+	if (ret)
+		goto out_socks;
+
+	if (nfsd_needs_lockd() && !nn->lockd_up) {
+		ret = lockd_up(net);
+		if (ret)
+			goto out_socks;
+		nn->lockd_up = 1;
+	}
+
+	ret = nfs4_state_start_net(net);
+	if (ret)
+		goto out_lockd;
+
+	nn->nfsd_net_up = true;
+	return 0;
+
+out_lockd:
+	if (nn->lockd_up) {
+		lockd_down(net);
+		nn->lockd_up = 0;
+	}
+out_socks:
+	nfsd_shutdown_generic();
+	return ret;
+}
+
+static void nfsd_shutdown_net(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	nfs4_state_shutdown_net(net);
+	if (nn->lockd_up) {
+		lockd_down(net);
+		nn->lockd_up = 0;
+	}
+	nn->nfsd_net_up = false;
+	nfsd_shutdown_generic();
+}
+
+static int nfsd_inetaddr_event(struct notifier_block *this, unsigned long event,
+	void *ptr)
+{
+	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
+	struct net_device *dev = ifa->ifa_dev->dev;
+	struct net *net = dev_net(dev);
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct sockaddr_in sin;
+
+	if ((event != NETDEV_DOWN) ||
+	    !atomic_inc_not_zero(&nn->ntf_refcnt))
+		goto out;
+
+	if (nn->nfsd_serv) {
+		dprintk("nfsd_inetaddr_event: removed %pI4\n", &ifa->ifa_local);
+		sin.sin_family = AF_INET;
+		sin.sin_addr.s_addr = ifa->ifa_local;
+		svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin);
+	}
+	atomic_dec(&nn->ntf_refcnt);
+	wake_up(&nn->ntf_wq);
+
+out:
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block nfsd_inetaddr_notifier = {
+	.notifier_call = nfsd_inetaddr_event,
+};
+
+#if IS_ENABLED(CONFIG_IPV6)
+static int nfsd_inet6addr_event(struct notifier_block *this,
+	unsigned long event, void *ptr)
+{
+	struct inet6_ifaddr *ifa = (struct inet6_ifaddr *)ptr;
+	struct net_device *dev = ifa->idev->dev;
+	struct net *net = dev_net(dev);
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct sockaddr_in6 sin6;
+
+	if ((event != NETDEV_DOWN) ||
+	    !atomic_inc_not_zero(&nn->ntf_refcnt))
+		goto out;
+
+	if (nn->nfsd_serv) {
+		dprintk("nfsd_inet6addr_event: removed %pI6\n", &ifa->addr);
+		sin6.sin6_family = AF_INET6;
+		sin6.sin6_addr = ifa->addr;
+		if (ipv6_addr_type(&sin6.sin6_addr) & IPV6_ADDR_LINKLOCAL)
+			sin6.sin6_scope_id = ifa->idev->dev->ifindex;
+		svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin6);
+	}
+	atomic_dec(&nn->ntf_refcnt);
+	wake_up(&nn->ntf_wq);
+out:
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block nfsd_inet6addr_notifier = {
+	.notifier_call = nfsd_inet6addr_event,
+};
+#endif
+
+/* Only used under nfsd_mutex, so this atomic may be overkill: */
+static atomic_t nfsd_notifier_refcount = ATOMIC_INIT(0);
+
+static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	atomic_dec(&nn->ntf_refcnt);
+	/* check if the notifier still has clients */
+	if (atomic_dec_return(&nfsd_notifier_refcount) == 0) {
+		unregister_inetaddr_notifier(&nfsd_inetaddr_notifier);
+#if IS_ENABLED(CONFIG_IPV6)
+		unregister_inet6addr_notifier(&nfsd_inet6addr_notifier);
+#endif
+	}
+	wait_event(nn->ntf_wq, atomic_read(&nn->ntf_refcnt) == 0);
+
+	/*
+	 * write_ports can create the server without actually starting
+	 * any threads--if we get shut down before any threads are
+	 * started, then nfsd_last_thread will be run before any of this
+	 * other initialization has been done except the rpcb information.
+	 */
+	svc_rpcb_cleanup(serv, net);
+	if (!nn->nfsd_net_up)
+		return;
+
+	nfsd_shutdown_net(net);
+	pr_info("nfsd: last server has exited, flushing export cache\n");
+	nfsd_export_flush(net);
+}
+
+void nfsd_reset_versions(void)
+{
+	int i;
+
+	for (i = 0; i < NFSD_NRVERS; i++)
+		if (nfsd_vers(i, NFSD_TEST))
+			return;
+
+	for (i = 0; i < NFSD_NRVERS; i++)
+		if (i != 4)
+			nfsd_vers(i, NFSD_SET);
+		else {
+			int minor = 0;
+			while (nfsd_minorversion(minor, NFSD_SET) >= 0)
+				minor++;
+		}
+}
+
+/*
+ * Each session guarantees a negotiated per slot memory cache for replies
+ * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated
+ * NFSv4.1 server might want to use more memory for a DRC than a machine
+ * with mutiple services.
+ *
+ * Impose a hard limit on the number of pages for the DRC which varies
+ * according to the machines free pages. This is of course only a default.
+ *
+ * For now this is a #defined shift which could be under admin control
+ * in the future.
+ */
+static void set_max_drc(void)
+{
+	#define NFSD_DRC_SIZE_SHIFT	7
+	nfsd_drc_max_mem = (nr_free_buffer_pages()
+					>> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
+	nfsd_drc_mem_used = 0;
+	spin_lock_init(&nfsd_drc_lock);
+	dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
+}
+
+static int nfsd_get_default_max_blksize(void)
+{
+	struct sysinfo i;
+	unsigned long long target;
+	unsigned long ret;
+
+	si_meminfo(&i);
+	target = (i.totalram - i.totalhigh) << PAGE_SHIFT;
+	/*
+	 * Aim for 1/4096 of memory per thread This gives 1MB on 4Gig
+	 * machines, but only uses 32K on 128M machines.  Bottom out at
+	 * 8K on 32M and smaller.  Of course, this is only a default.
+	 */
+	target >>= 12;
+
+	ret = NFSSVC_MAXBLKSIZE;
+	while (ret > target && ret >= 8*1024*2)
+		ret /= 2;
+	return ret;
+}
+
+static const struct svc_serv_ops nfsd_thread_sv_ops = {
+	.svo_shutdown		= nfsd_last_thread,
+	.svo_function		= nfsd,
+	.svo_enqueue_xprt	= svc_xprt_do_enqueue,
+	.svo_setup		= svc_set_num_threads,
+	.svo_module		= THIS_MODULE,
+};
+
+int nfsd_create_serv(struct net *net)
+{
+	int error;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	WARN_ON(!mutex_is_locked(&nfsd_mutex));
+	if (nn->nfsd_serv) {
+		svc_get(nn->nfsd_serv);
+		return 0;
+	}
+	if (nfsd_max_blksize == 0)
+		nfsd_max_blksize = nfsd_get_default_max_blksize();
+	nfsd_reset_versions();
+	nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
+						&nfsd_thread_sv_ops);
+	if (nn->nfsd_serv == NULL)
+		return -ENOMEM;
+
+	nn->nfsd_serv->sv_maxconn = nn->max_connections;
+	error = svc_bind(nn->nfsd_serv, net);
+	if (error < 0) {
+		svc_destroy(nn->nfsd_serv);
+		return error;
+	}
+
+	set_max_drc();
+	/* check if the notifier is already set */
+	if (atomic_inc_return(&nfsd_notifier_refcount) == 1) {
+		register_inetaddr_notifier(&nfsd_inetaddr_notifier);
+#if IS_ENABLED(CONFIG_IPV6)
+		register_inet6addr_notifier(&nfsd_inet6addr_notifier);
+#endif
+	}
+	atomic_inc(&nn->ntf_refcnt);
+	ktime_get_real_ts64(&nn->nfssvc_boot); /* record boot time */
+	return 0;
+}
+
+int nfsd_nrpools(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	if (nn->nfsd_serv == NULL)
+		return 0;
+	else
+		return nn->nfsd_serv->sv_nrpools;
+}
+
+int nfsd_get_nrthreads(int n, int *nthreads, struct net *net)
+{
+	int i = 0;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	if (nn->nfsd_serv != NULL) {
+		for (i = 0; i < nn->nfsd_serv->sv_nrpools && i < n; i++)
+			nthreads[i] = nn->nfsd_serv->sv_pools[i].sp_nrthreads;
+	}
+
+	return 0;
+}
+
+void nfsd_destroy(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	int destroy = (nn->nfsd_serv->sv_nrthreads == 1);
+
+	if (destroy)
+		svc_shutdown_net(nn->nfsd_serv, net);
+	svc_destroy(nn->nfsd_serv);
+	if (destroy)
+		nn->nfsd_serv = NULL;
+}
+
+int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
+{
+	int i = 0;
+	int tot = 0;
+	int err = 0;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	WARN_ON(!mutex_is_locked(&nfsd_mutex));
+
+	if (nn->nfsd_serv == NULL || n <= 0)
+		return 0;
+
+	if (n > nn->nfsd_serv->sv_nrpools)
+		n = nn->nfsd_serv->sv_nrpools;
+
+	/* enforce a global maximum number of threads */
+	tot = 0;
+	for (i = 0; i < n; i++) {
+		nthreads[i] = min(nthreads[i], NFSD_MAXSERVS);
+		tot += nthreads[i];
+	}
+	if (tot > NFSD_MAXSERVS) {
+		/* total too large: scale down requested numbers */
+		for (i = 0; i < n && tot > 0; i++) {
+		    	int new = nthreads[i] * NFSD_MAXSERVS / tot;
+			tot -= (nthreads[i] - new);
+			nthreads[i] = new;
+		}
+		for (i = 0; i < n && tot > 0; i++) {
+			nthreads[i]--;
+			tot--;
+		}
+	}
+
+	/*
+	 * There must always be a thread in pool 0; the admin
+	 * can't shut down NFS completely using pool_threads.
+	 */
+	if (nthreads[0] == 0)
+		nthreads[0] = 1;
+
+	/* apply the new numbers */
+	svc_get(nn->nfsd_serv);
+	for (i = 0; i < n; i++) {
+		err = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv,
+				&nn->nfsd_serv->sv_pools[i], nthreads[i]);
+		if (err)
+			break;
+	}
+	nfsd_destroy(net);
+	return err;
+}
+
+/*
+ * Adjust the number of threads and return the new number of threads.
+ * This is also the function that starts the server if necessary, if
+ * this is the first time nrservs is nonzero.
+ */
+int
+nfsd_svc(int nrservs, struct net *net)
+{
+	int	error;
+	bool	nfsd_up_before;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	mutex_lock(&nfsd_mutex);
+	dprintk("nfsd: creating service\n");
+
+	nrservs = max(nrservs, 0);
+	nrservs = min(nrservs, NFSD_MAXSERVS);
+	error = 0;
+
+	if (nrservs == 0 && nn->nfsd_serv == NULL)
+		goto out;
+
+	error = nfsd_create_serv(net);
+	if (error)
+		goto out;
+
+	nfsd_up_before = nn->nfsd_net_up;
+
+	error = nfsd_startup_net(nrservs, net);
+	if (error)
+		goto out_destroy;
+	error = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv,
+			NULL, nrservs);
+	if (error)
+		goto out_shutdown;
+	/* We are holding a reference to nn->nfsd_serv which
+	 * we don't want to count in the return value,
+	 * so subtract 1
+	 */
+	error = nn->nfsd_serv->sv_nrthreads - 1;
+out_shutdown:
+	if (error < 0 && !nfsd_up_before)
+		nfsd_shutdown_net(net);
+out_destroy:
+	nfsd_destroy(net);		/* Release server */
+out:
+	mutex_unlock(&nfsd_mutex);
+	return error;
+}
+
+
+/*
+ * This is the NFS server kernel thread
+ */
+static int
+nfsd(void *vrqstp)
+{
+	struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
+	struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list);
+	struct net *net = perm_sock->xpt_net;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	int err;
+
+	/* Lock module and set up kernel thread */
+	mutex_lock(&nfsd_mutex);
+
+	/* At this point, the thread shares current->fs
+	 * with the init process. We need to create files with the
+	 * umask as defined by the client instead of init's umask. */
+	if (unshare_fs_struct() < 0) {
+		printk("Unable to start nfsd thread: out of memory\n");
+		goto out;
+	}
+
+	current->fs->umask = 0;
+
+	/*
+	 * thread is spawned with all signals set to SIG_IGN, re-enable
+	 * the ones that will bring down the thread
+	 */
+	allow_signal(SIGKILL);
+	allow_signal(SIGHUP);
+	allow_signal(SIGINT);
+	allow_signal(SIGQUIT);
+
+	nfsdstats.th_cnt++;
+	mutex_unlock(&nfsd_mutex);
+
+	set_freezable();
+
+	/*
+	 * The main request loop
+	 */
+	for (;;) {
+		/* Update sv_maxconn if it has changed */
+		rqstp->rq_server->sv_maxconn = nn->max_connections;
+
+		/*
+		 * Find a socket with data available and call its
+		 * recvfrom routine.
+		 */
+		while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
+			;
+		if (err == -EINTR)
+			break;
+		validate_process_creds();
+		svc_process(rqstp);
+		validate_process_creds();
+	}
+
+	/* Clear signals before calling svc_exit_thread() */
+	flush_signals(current);
+
+	mutex_lock(&nfsd_mutex);
+	nfsdstats.th_cnt --;
+
+out:
+	rqstp->rq_server = NULL;
+
+	/* Release the thread */
+	svc_exit_thread(rqstp);
+
+	nfsd_destroy(net);
+
+	/* Release module */
+	mutex_unlock(&nfsd_mutex);
+	module_put_and_exit(0);
+	return 0;
+}
+
+static __be32 map_new_errors(u32 vers, __be32 nfserr)
+{
+	if (nfserr == nfserr_jukebox && vers == 2)
+		return nfserr_dropit;
+	if (nfserr == nfserr_wrongsec && vers < 4)
+		return nfserr_acces;
+	return nfserr;
+}
+
+/*
+ * A write procedure can have a large argument, and a read procedure can
+ * have a large reply, but no NFSv2 or NFSv3 procedure has argument and
+ * reply that can both be larger than a page.  The xdr code has taken
+ * advantage of this assumption to be a sloppy about bounds checking in
+ * some cases.  Pending a rewrite of the NFSv2/v3 xdr code to fix that
+ * problem, we enforce these assumptions here:
+ */
+static bool nfs_request_too_big(struct svc_rqst *rqstp,
+				const struct svc_procedure *proc)
+{
+	/*
+	 * The ACL code has more careful bounds-checking and is not
+	 * susceptible to this problem:
+	 */
+	if (rqstp->rq_prog != NFS_PROGRAM)
+		return false;
+	/*
+	 * Ditto NFSv4 (which can in theory have argument and reply both
+	 * more than a page):
+	 */
+	if (rqstp->rq_vers >= 4)
+		return false;
+	/* The reply will be small, we're OK: */
+	if (proc->pc_xdrressize > 0 &&
+	    proc->pc_xdrressize < XDR_QUADLEN(PAGE_SIZE))
+		return false;
+
+	return rqstp->rq_arg.len > PAGE_SIZE;
+}
+
+int
+nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
+{
+	const struct svc_procedure *proc;
+	__be32			nfserr;
+	__be32			*nfserrp;
+
+	dprintk("nfsd_dispatch: vers %d proc %d\n",
+				rqstp->rq_vers, rqstp->rq_proc);
+	proc = rqstp->rq_procinfo;
+
+	if (nfs_request_too_big(rqstp, proc)) {
+		dprintk("nfsd: NFSv%d argument too large\n", rqstp->rq_vers);
+		*statp = rpc_garbage_args;
+		return 1;
+	}
+	/*
+	 * Give the xdr decoder a chance to change this if it wants
+	 * (necessary in the NFSv4.0 compound case)
+	 */
+	rqstp->rq_cachetype = proc->pc_cachetype;
+	/* Decode arguments */
+	if (proc->pc_decode &&
+	    !proc->pc_decode(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base)) {
+		dprintk("nfsd: failed to decode arguments!\n");
+		*statp = rpc_garbage_args;
+		return 1;
+	}
+
+	/* Check whether we have this call in the cache. */
+	switch (nfsd_cache_lookup(rqstp)) {
+	case RC_DROPIT:
+		return 0;
+	case RC_REPLY:
+		return 1;
+	case RC_DOIT:;
+		/* do it */
+	}
+
+	/* need to grab the location to store the status, as
+	 * nfsv4 does some encoding while processing 
+	 */
+	nfserrp = rqstp->rq_res.head[0].iov_base
+		+ rqstp->rq_res.head[0].iov_len;
+	rqstp->rq_res.head[0].iov_len += sizeof(__be32);
+
+	/* Now call the procedure handler, and encode NFS status. */
+	nfserr = proc->pc_func(rqstp);
+	nfserr = map_new_errors(rqstp->rq_vers, nfserr);
+	if (nfserr == nfserr_dropit || test_bit(RQ_DROPME, &rqstp->rq_flags)) {
+		dprintk("nfsd: Dropping request; may be revisited later\n");
+		nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
+		return 0;
+	}
+
+	if (rqstp->rq_proc != 0)
+		*nfserrp++ = nfserr;
+
+	/* Encode result.
+	 * For NFSv2, additional info is never returned in case of an error.
+	 */
+	if (!(nfserr && rqstp->rq_vers == 2)) {
+		if (proc->pc_encode && !proc->pc_encode(rqstp, nfserrp)) {
+			/* Failed to encode result. Release cache entry */
+			dprintk("nfsd: failed to encode result!\n");
+			nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
+			*statp = rpc_system_err;
+			return 1;
+		}
+	}
+
+	/* Store reply in cache. */
+	nfsd_cache_update(rqstp, rqstp->rq_cachetype, statp + 1);
+	return 1;
+}
+
+int nfsd_pool_stats_open(struct inode *inode, struct file *file)
+{
+	int ret;
+	struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id);
+
+	mutex_lock(&nfsd_mutex);
+	if (nn->nfsd_serv == NULL) {
+		mutex_unlock(&nfsd_mutex);
+		return -ENODEV;
+	}
+	/* bump up the psudo refcount while traversing */
+	svc_get(nn->nfsd_serv);
+	ret = svc_pool_stats_open(nn->nfsd_serv, file);
+	mutex_unlock(&nfsd_mutex);
+	return ret;
+}
+
+int nfsd_pool_stats_release(struct inode *inode, struct file *file)
+{
+	int ret = seq_release(inode, file);
+	struct net *net = inode->i_sb->s_fs_info;
+
+	mutex_lock(&nfsd_mutex);
+	/* this function really, really should have been called svc_put() */
+	nfsd_destroy(net);
+	mutex_unlock(&nfsd_mutex);
+	return ret;
+}