Adding upstream version 6.1.76.upstream/6.1.76

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

1 files changed, 1149 insertions, 0 deletions

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
new file mode 100644
index 000000000..c7695ebd2
--- /dev/null
+++ b/fs/nfsd/nfssvc.c
@@ -0,0 +1,1149 @@
+// 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/siphash.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"
+#include "filecache.h"
+
+#include "trace.h"
+
+#define NFSDDBG_FACILITY	NFSDDBG_SVC
+
+extern struct svc_program	nfsd_program;
+static int			nfsd(void *vrqstp);
+#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
+static int			nfsd_acl_rpcbind_set(struct net *,
+						     const struct svc_program *,
+						     u32, int,
+						     unsigned short,
+						     unsigned short);
+static __be32			nfsd_acl_init_request(struct svc_rqst *,
+						const struct svc_program *,
+						struct svc_process_info *);
+#endif
+static int			nfsd_rpcbind_set(struct net *,
+						 const struct svc_program *,
+						 u32, int,
+						 unsigned short,
+						 unsigned short);
+static __be32			nfsd_init_request(struct svc_rqst *,
+						const struct svc_program *,
+						struct svc_process_info *);
+
+/*
+ * nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and some members
+ * of the svc_serv struct such as ->sv_temp_socks and ->sv_permsocks.
+ *
+ * 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 (unless
+ * nn->keep_active is set).  That number of nfsd threads must
+ * exist and each must be listed in ->sp_all_threads in some entry of
+ * ->sv_pools[].
+ *
+ * Each active thread holds a counted reference on nn->nfsd_serv, as does
+ * the nn->keep_active flag and various transient calls to svc_get().
+ *
+ * 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.
+ */
+DEFINE_SPINLOCK(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 struct svc_program	nfsd_acl_program = {
+	.pg_prog		= NFS_ACL_PROGRAM,
+	.pg_nvers		= NFSD_ACL_NRVERS,
+	.pg_vers		= nfsd_acl_version,
+	.pg_name		= "nfsacl",
+	.pg_class		= "nfsd",
+	.pg_stats		= &nfsd_acl_svcstats,
+	.pg_authenticate	= &svc_set_client,
+	.pg_init_request	= nfsd_acl_init_request,
+	.pg_rpcbind_set		= nfsd_acl_rpcbind_set,
+};
+
+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,
+	[3] = &nfsd_version3,
+#if defined(CONFIG_NFSD_V4)
+	[4] = &nfsd_version4,
+#endif
+};
+
+#define NFSD_MINVERS    	2
+#define NFSD_NRVERS		ARRAY_SIZE(nfsd_version)
+
+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_version,		/* 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 */
+	.pg_init_request	= nfsd_init_request,
+	.pg_rpcbind_set		= nfsd_rpcbind_set,
+};
+
+static bool
+nfsd_support_version(int vers)
+{
+	if (vers >= NFSD_MINVERS && vers < NFSD_NRVERS)
+		return nfsd_version[vers] != NULL;
+	return false;
+}
+
+static bool *
+nfsd_alloc_versions(void)
+{
+	bool *vers = kmalloc_array(NFSD_NRVERS, sizeof(bool), GFP_KERNEL);
+	unsigned i;
+
+	if (vers) {
+		/* All compiled versions are enabled by default */
+		for (i = 0; i < NFSD_NRVERS; i++)
+			vers[i] = nfsd_support_version(i);
+	}
+	return vers;
+}
+
+static bool *
+nfsd_alloc_minorversions(void)
+{
+	bool *vers = kmalloc_array(NFSD_SUPPORTED_MINOR_VERSION + 1,
+			sizeof(bool), GFP_KERNEL);
+	unsigned i;
+
+	if (vers) {
+		/* All minor versions are enabled by default */
+		for (i = 0; i <= NFSD_SUPPORTED_MINOR_VERSION; i++)
+			vers[i] = nfsd_support_version(4);
+	}
+	return vers;
+}
+
+void
+nfsd_netns_free_versions(struct nfsd_net *nn)
+{
+	kfree(nn->nfsd_versions);
+	kfree(nn->nfsd4_minorversions);
+	nn->nfsd_versions = NULL;
+	nn->nfsd4_minorversions = NULL;
+}
+
+static void
+nfsd_netns_init_versions(struct nfsd_net *nn)
+{
+	if (!nn->nfsd_versions) {
+		nn->nfsd_versions = nfsd_alloc_versions();
+		nn->nfsd4_minorversions = nfsd_alloc_minorversions();
+		if (!nn->nfsd_versions || !nn->nfsd4_minorversions)
+			nfsd_netns_free_versions(nn);
+	}
+}
+
+int nfsd_vers(struct nfsd_net *nn, int vers, enum vers_op change)
+{
+	if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
+		return 0;
+	switch(change) {
+	case NFSD_SET:
+		if (nn->nfsd_versions)
+			nn->nfsd_versions[vers] = nfsd_support_version(vers);
+		break;
+	case NFSD_CLEAR:
+		nfsd_netns_init_versions(nn);
+		if (nn->nfsd_versions)
+			nn->nfsd_versions[vers] = false;
+		break;
+	case NFSD_TEST:
+		if (nn->nfsd_versions)
+			return nn->nfsd_versions[vers];
+		fallthrough;
+	case NFSD_AVAIL:
+		return nfsd_support_version(vers);
+	}
+	return 0;
+}
+
+static void
+nfsd_adjust_nfsd_versions4(struct nfsd_net *nn)
+{
+	unsigned i;
+
+	for (i = 0; i <= NFSD_SUPPORTED_MINOR_VERSION; i++) {
+		if (nn->nfsd4_minorversions[i])
+			return;
+	}
+	nfsd_vers(nn, 4, NFSD_CLEAR);
+}
+
+int nfsd_minorversion(struct nfsd_net *nn, u32 minorversion, enum vers_op change)
+{
+	if (minorversion > NFSD_SUPPORTED_MINOR_VERSION &&
+	    change != NFSD_AVAIL)
+		return -1;
+
+	switch(change) {
+	case NFSD_SET:
+		if (nn->nfsd4_minorversions) {
+			nfsd_vers(nn, 4, NFSD_SET);
+			nn->nfsd4_minorversions[minorversion] =
+				nfsd_vers(nn, 4, NFSD_TEST);
+		}
+		break;
+	case NFSD_CLEAR:
+		nfsd_netns_init_versions(nn);
+		if (nn->nfsd4_minorversions) {
+			nn->nfsd4_minorversions[minorversion] = false;
+			nfsd_adjust_nfsd_versions4(nn);
+		}
+		break;
+	case NFSD_TEST:
+		if (nn->nfsd4_minorversions)
+			return nn->nfsd4_minorversions[minorversion];
+		return nfsd_vers(nn, 4, NFSD_TEST);
+	case NFSD_AVAIL:
+		return minorversion <= NFSD_SUPPORTED_MINOR_VERSION &&
+			nfsd_vers(nn, 4, NFSD_AVAIL);
+	}
+	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, const struct cred *cred)
+{
+	int error;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	if (!list_empty(&nn->nfsd_serv->sv_permsocks))
+		return 0;
+
+	error = svc_xprt_create(nn->nfsd_serv, "udp", net, PF_INET, NFS_PORT,
+				SVC_SOCK_DEFAULTS, cred);
+	if (error < 0)
+		return error;
+
+	error = svc_xprt_create(nn->nfsd_serv, "tcp", net, PF_INET, NFS_PORT,
+				SVC_SOCK_DEFAULTS, cred);
+	if (error < 0)
+		return error;
+
+	return 0;
+}
+
+static int nfsd_users = 0;
+
+static int nfsd_startup_generic(void)
+{
+	int ret;
+
+	if (nfsd_users++)
+		return 0;
+
+	ret = nfsd_file_cache_init();
+	if (ret)
+		goto dec_users;
+
+	ret = nfs4_state_start();
+	if (ret)
+		goto out_file_cache;
+	return 0;
+
+out_file_cache:
+	nfsd_file_cache_shutdown();
+dec_users:
+	nfsd_users--;
+	return ret;
+}
+
+static void nfsd_shutdown_generic(void)
+{
+	if (--nfsd_users)
+		return;
+
+	nfs4_state_shutdown();
+	nfsd_file_cache_shutdown();
+}
+
+static bool nfsd_needs_lockd(struct nfsd_net *nn)
+{
+	return nfsd_vers(nn, 2, NFSD_TEST) || nfsd_vers(nn, 3, NFSD_TEST);
+}
+
+/**
+ * nfsd_copy_write_verifier - Atomically copy a write verifier
+ * @verf: buffer in which to receive the verifier cookie
+ * @nn: NFS net namespace
+ *
+ * This function provides a wait-free mechanism for copying the
+ * namespace's write verifier without tearing it.
+ */
+void nfsd_copy_write_verifier(__be32 verf[2], struct nfsd_net *nn)
+{
+	int seq = 0;
+
+	do {
+		read_seqbegin_or_lock(&nn->writeverf_lock, &seq);
+		memcpy(verf, nn->writeverf, sizeof(nn->writeverf));
+	} while (need_seqretry(&nn->writeverf_lock, seq));
+	done_seqretry(&nn->writeverf_lock, seq);
+}
+
+static void nfsd_reset_write_verifier_locked(struct nfsd_net *nn)
+{
+	struct timespec64 now;
+	u64 verf;
+
+	/*
+	 * Because the time value is hashed, y2038 time_t overflow
+	 * is irrelevant in this usage.
+	 */
+	ktime_get_raw_ts64(&now);
+	verf = siphash_2u64(now.tv_sec, now.tv_nsec, &nn->siphash_key);
+	memcpy(nn->writeverf, &verf, sizeof(nn->writeverf));
+}
+
+/**
+ * nfsd_reset_write_verifier - Generate a new write verifier
+ * @nn: NFS net namespace
+ *
+ * This function updates the ->writeverf field of @nn. This field
+ * contains an opaque cookie that, according to Section 18.32.3 of
+ * RFC 8881, "the client can use to determine whether a server has
+ * changed instance state (e.g., server restart) between a call to
+ * WRITE and a subsequent call to either WRITE or COMMIT.  This
+ * cookie MUST be unchanged during a single instance of the NFSv4.1
+ * server and MUST be unique between instances of the NFSv4.1
+ * server."
+ */
+void nfsd_reset_write_verifier(struct nfsd_net *nn)
+{
+	write_seqlock(&nn->writeverf_lock);
+	nfsd_reset_write_verifier_locked(nn);
+	write_sequnlock(&nn->writeverf_lock);
+}
+
+static int nfsd_startup_net(struct net *net, const struct cred *cred)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	int ret;
+
+	if (nn->nfsd_net_up)
+		return 0;
+
+	ret = nfsd_startup_generic();
+	if (ret)
+		return ret;
+	ret = nfsd_init_socks(net, cred);
+	if (ret)
+		goto out_socks;
+
+	if (nfsd_needs_lockd(nn) && !nn->lockd_up) {
+		ret = lockd_up(net, cred);
+		if (ret)
+			goto out_socks;
+		nn->lockd_up = true;
+	}
+
+	ret = nfsd_file_cache_start_net(net);
+	if (ret)
+		goto out_lockd;
+	ret = nfs4_state_start_net(net);
+	if (ret)
+		goto out_filecache;
+
+#ifdef CONFIG_NFSD_V4_2_INTER_SSC
+	nfsd4_ssc_init_umount_work(nn);
+#endif
+	nn->nfsd_net_up = true;
+	return 0;
+
+out_filecache:
+	nfsd_file_cache_shutdown_net(net);
+out_lockd:
+	if (nn->lockd_up) {
+		lockd_down(net);
+		nn->lockd_up = false;
+	}
+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);
+	nfsd_file_cache_shutdown_net(net);
+	if (nn->lockd_up) {
+		lockd_down(net);
+		nn->lockd_up = false;
+	}
+	nn->nfsd_net_up = false;
+	nfsd_shutdown_generic();
+}
+
+static DEFINE_SPINLOCK(nfsd_notifier_lock);
+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 || !nn->nfsd_serv)
+		goto out;
+
+	spin_lock(&nfsd_notifier_lock);
+	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);
+	}
+	spin_unlock(&nfsd_notifier_lock);
+
+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 || !nn->nfsd_serv)
+		goto out;
+
+	spin_lock(&nfsd_notifier_lock);
+	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);
+	}
+	spin_unlock(&nfsd_notifier_lock);
+
+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);
+
+	/* 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
+	}
+
+	/*
+	 * 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(struct nfsd_net *nn)
+{
+	int i;
+
+	for (i = 0; i < NFSD_NRVERS; i++)
+		if (nfsd_vers(nn, i, NFSD_TEST))
+			return;
+
+	for (i = 0; i < NFSD_NRVERS; i++)
+		if (i != 4)
+			nfsd_vers(nn, i, NFSD_SET);
+		else {
+			int minor = 0;
+			while (nfsd_minorversion(nn, 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;
+	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;
+}
+
+void nfsd_shutdown_threads(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct svc_serv *serv;
+
+	mutex_lock(&nfsd_mutex);
+	serv = nn->nfsd_serv;
+	if (serv == NULL) {
+		mutex_unlock(&nfsd_mutex);
+		return;
+	}
+
+	svc_get(serv);
+	/* Kill outstanding nfsd threads */
+	svc_set_num_threads(serv, NULL, 0);
+	nfsd_put(net);
+	mutex_unlock(&nfsd_mutex);
+}
+
+bool i_am_nfsd(void)
+{
+	return kthread_func(current) == nfsd;
+}
+
+int nfsd_create_serv(struct net *net)
+{
+	int error;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct svc_serv *serv;
+
+	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);
+	serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize, nfsd);
+	if (serv == NULL)
+		return -ENOMEM;
+
+	serv->sv_maxconn = nn->max_connections;
+	error = svc_bind(serv, net);
+	if (error < 0) {
+		/* NOT nfsd_put() as notifiers (see below) haven't
+		 * been set up yet.
+		 */
+		svc_put(serv);
+		return error;
+	}
+	spin_lock(&nfsd_notifier_lock);
+	nn->nfsd_serv = serv;
+	spin_unlock(&nfsd_notifier_lock);
+
+	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
+	}
+	nfsd_reset_write_verifier(nn);
+	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;
+}
+
+/* This is the callback for kref_put() below.
+ * There is no code here as the first thing to be done is
+ * call svc_shutdown_net(), but we cannot get the 'net' from
+ * the kref.  So do all the work when kref_put returns true.
+ */
+static void nfsd_noop(struct kref *ref)
+{
+}
+
+void nfsd_put(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	if (kref_put(&nn->nfsd_serv->sv_refcnt, nfsd_noop)) {
+		svc_xprt_destroy_all(nn->nfsd_serv, net);
+		nfsd_last_thread(nn->nfsd_serv, net);
+		svc_destroy(&nn->nfsd_serv->sv_refcnt);
+		spin_lock(&nfsd_notifier_lock);
+		nn->nfsd_serv = NULL;
+		spin_unlock(&nfsd_notifier_lock);
+	}
+}
+
+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 = svc_set_num_threads(nn->nfsd_serv,
+					  &nn->nfsd_serv->sv_pools[i],
+					  nthreads[i]);
+		if (err)
+			break;
+	}
+	nfsd_put(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, const struct cred *cred)
+{
+	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;
+
+	strscpy(nn->nfsd_name, utsname()->nodename,
+		sizeof(nn->nfsd_name));
+
+	error = nfsd_create_serv(net);
+	if (error)
+		goto out;
+
+	nfsd_up_before = nn->nfsd_net_up;
+
+	error = nfsd_startup_net(net, cred);
+	if (error)
+		goto out_put;
+	error = svc_set_num_threads(nn->nfsd_serv, NULL, nrservs);
+	if (error)
+		goto out_shutdown;
+	error = nn->nfsd_serv->sv_nrthreads;
+out_shutdown:
+	if (error < 0 && !nfsd_up_before)
+		nfsd_shutdown_net(net);
+out_put:
+	/* Threads now hold service active */
+	if (xchg(&nn->keep_active, 0))
+		nfsd_put(net);
+	nfsd_put(net);
+out:
+	mutex_unlock(&nfsd_mutex);
+	return error;
+}
+
+#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
+static bool
+nfsd_support_acl_version(int vers)
+{
+	if (vers >= NFSD_ACL_MINVERS && vers < NFSD_ACL_NRVERS)
+		return nfsd_acl_version[vers] != NULL;
+	return false;
+}
+
+static int
+nfsd_acl_rpcbind_set(struct net *net, const struct svc_program *progp,
+		     u32 version, int family, unsigned short proto,
+		     unsigned short port)
+{
+	if (!nfsd_support_acl_version(version) ||
+	    !nfsd_vers(net_generic(net, nfsd_net_id), version, NFSD_TEST))
+		return 0;
+	return svc_generic_rpcbind_set(net, progp, version, family,
+			proto, port);
+}
+
+static __be32
+nfsd_acl_init_request(struct svc_rqst *rqstp,
+		      const struct svc_program *progp,
+		      struct svc_process_info *ret)
+{
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+	int i;
+
+	if (likely(nfsd_support_acl_version(rqstp->rq_vers) &&
+	    nfsd_vers(nn, rqstp->rq_vers, NFSD_TEST)))
+		return svc_generic_init_request(rqstp, progp, ret);
+
+	ret->mismatch.lovers = NFSD_ACL_NRVERS;
+	for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++) {
+		if (nfsd_support_acl_version(rqstp->rq_vers) &&
+		    nfsd_vers(nn, i, NFSD_TEST)) {
+			ret->mismatch.lovers = i;
+			break;
+		}
+	}
+	if (ret->mismatch.lovers == NFSD_ACL_NRVERS)
+		return rpc_prog_unavail;
+	ret->mismatch.hivers = NFSD_ACL_MINVERS;
+	for (i = NFSD_ACL_NRVERS - 1; i >= NFSD_ACL_MINVERS; i--) {
+		if (nfsd_support_acl_version(rqstp->rq_vers) &&
+		    nfsd_vers(nn, i, NFSD_TEST)) {
+			ret->mismatch.hivers = i;
+			break;
+		}
+	}
+	return rpc_prog_mismatch;
+}
+#endif
+
+static int
+nfsd_rpcbind_set(struct net *net, const struct svc_program *progp,
+		 u32 version, int family, unsigned short proto,
+		 unsigned short port)
+{
+	if (!nfsd_vers(net_generic(net, nfsd_net_id), version, NFSD_TEST))
+		return 0;
+	return svc_generic_rpcbind_set(net, progp, version, family,
+			proto, port);
+}
+
+static __be32
+nfsd_init_request(struct svc_rqst *rqstp,
+		  const struct svc_program *progp,
+		  struct svc_process_info *ret)
+{
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+	int i;
+
+	if (likely(nfsd_vers(nn, rqstp->rq_vers, NFSD_TEST)))
+		return svc_generic_init_request(rqstp, progp, ret);
+
+	ret->mismatch.lovers = NFSD_NRVERS;
+	for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
+		if (nfsd_vers(nn, i, NFSD_TEST)) {
+			ret->mismatch.lovers = i;
+			break;
+		}
+	}
+	if (ret->mismatch.lovers == NFSD_NRVERS)
+		return rpc_prog_unavail;
+	ret->mismatch.hivers = NFSD_MINVERS;
+	for (i = NFSD_NRVERS - 1; i >= NFSD_MINVERS; i--) {
+		if (nfsd_vers(nn, i, NFSD_TEST)) {
+			ret->mismatch.hivers = i;
+			break;
+		}
+	}
+	return rpc_prog_mismatch;
+}
+
+/*
+ * 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;
+
+	/* 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);
+
+	atomic_inc(&nfsdstats.th_cnt);
+
+	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);
+
+	atomic_dec(&nfsdstats.th_cnt);
+
+out:
+	/* Take an extra ref so that the svc_put in svc_exit_thread()
+	 * doesn't call svc_destroy()
+	 */
+	svc_get(nn->nfsd_serv);
+
+	/* Release the thread */
+	svc_exit_thread(rqstp);
+
+	/* We need to drop a ref, but may not drop the last reference
+	 * without holding nfsd_mutex, and we cannot wait for nfsd_mutex as that
+	 * could deadlock with nfsd_shutdown_threads() waiting for us.
+	 * So three options are:
+	 * - drop a non-final reference,
+	 * - get the mutex without waiting
+	 * - sleep briefly andd try the above again
+	 */
+	while (!svc_put_not_last(nn->nfsd_serv)) {
+		if (mutex_trylock(&nfsd_mutex)) {
+			nfsd_put(net);
+			mutex_unlock(&nfsd_mutex);
+			break;
+		}
+		msleep(20);
+	}
+
+	return 0;
+}
+
+/**
+ * nfsd_dispatch - Process an NFS or NFSACL Request
+ * @rqstp: incoming request
+ * @statp: pointer to location of accept_stat field in RPC Reply buffer
+ *
+ * This RPC dispatcher integrates the NFS server's duplicate reply cache.
+ *
+ * Return values:
+ *  %0: Processing complete; do not send a Reply
+ *  %1: Processing complete; send Reply in rqstp->rq_res
+ */
+int nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
+{
+	const struct svc_procedure *proc = rqstp->rq_procinfo;
+	unsigned int start, len;
+	__be32 *nfs_reply;
+
+	/*
+	 * 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;
+
+	svcxdr_init_decode(rqstp);
+
+	/*
+	 * ->pc_decode advances the argument stream past the NFS
+	 * Call header, so grab the header's starting location and
+	 * size now for the call to nfsd_cache_lookup().
+	 */
+	start = xdr_stream_pos(&rqstp->rq_arg_stream);
+	len = xdr_stream_remaining(&rqstp->rq_arg_stream);
+	if (!proc->pc_decode(rqstp, &rqstp->rq_arg_stream))
+		goto out_decode_err;
+
+	switch (nfsd_cache_lookup(rqstp, start, len)) {
+	case RC_DOIT:
+		break;
+	case RC_REPLY:
+		goto out_cached_reply;
+	case RC_DROPIT:
+		goto out_dropit;
+	}
+
+	/*
+	 * Need to grab the location to store the status, as
+	 * NFSv4 does some encoding while processing
+	 */
+	svcxdr_init_encode(rqstp);
+
+	nfs_reply = xdr_inline_decode(&rqstp->rq_res_stream, 0);
+	*statp = proc->pc_func(rqstp);
+	if (*statp == rpc_drop_reply || test_bit(RQ_DROPME, &rqstp->rq_flags))
+		goto out_update_drop;
+
+	if (!proc->pc_encode(rqstp, &rqstp->rq_res_stream))
+		goto out_encode_err;
+
+	nfsd_cache_update(rqstp, rqstp->rq_cachetype, nfs_reply);
+out_cached_reply:
+	return 1;
+
+out_decode_err:
+	trace_nfsd_garbage_args_err(rqstp);
+	*statp = rpc_garbage_args;
+	return 1;
+
+out_update_drop:
+	nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
+out_dropit:
+	return 0;
+
+out_encode_err:
+	trace_nfsd_cant_encode_err(rqstp);
+	nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
+	*statp = rpc_system_err;
+	return 1;
+}
+
+/**
+ * nfssvc_decode_voidarg - Decode void arguments
+ * @rqstp: Server RPC transaction context
+ * @xdr: XDR stream positioned at arguments to decode
+ *
+ * Return values:
+ *   %false: Arguments were not valid
+ *   %true: Decoding was successful
+ */
+bool nfssvc_decode_voidarg(struct svc_rqst *rqstp, struct xdr_stream *xdr)
+{
+	return true;
+}
+
+/**
+ * nfssvc_encode_voidres - Encode void results
+ * @rqstp: Server RPC transaction context
+ * @xdr: XDR stream into which to encode results
+ *
+ * Return values:
+ *   %false: Local error while encoding
+ *   %true: Encoding was successful
+ */
+bool nfssvc_encode_voidres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
+{
+	return true;
+}
+
+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;
+	}
+	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)
+{
+	struct seq_file *seq = file->private_data;
+	struct svc_serv *serv = seq->private;
+	int ret = seq_release(inode, file);
+
+	mutex_lock(&nfsd_mutex);
+	svc_put(serv);
+	mutex_unlock(&nfsd_mutex);
+	return ret;
+}