nfssvc.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Central processing for nfsd.
   4 *
   5 * Authors:	Olaf Kirch (okir@monad.swb.de)
   6 *
   7 * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
   8 */
   9
  10#include <linux/sched/signal.h>
  11#include <linux/freezer.h>
  12#include <linux/module.h>
  13#include <linux/fs_struct.h>
  14#include <linux/swap.h>
  15#include <linux/siphash.h>
  16
  17#include <linux/sunrpc/stats.h>
  18#include <linux/sunrpc/svcsock.h>
  19#include <linux/sunrpc/svc_xprt.h>
  20#include <linux/lockd/bind.h>
  21#include <linux/nfsacl.h>
  22#include <linux/nfslocalio.h>
  23#include <linux/seq_file.h>
  24#include <linux/inetdevice.h>
  25#include <net/addrconf.h>
  26#include <net/ipv6.h>
  27#include <net/net_namespace.h>
  28#include "nfsd.h"
  29#include "cache.h"
  30#include "vfs.h"
  31#include "netns.h"
  32#include "filecache.h"
  33
  34#include "trace.h"
  35
  36#define NFSDDBG_FACILITY	NFSDDBG_SVC
  37
  38atomic_t			nfsd_th_cnt = ATOMIC_INIT(0);
  39static int			nfsd(void *vrqstp);
  40#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
  41static int			nfsd_acl_rpcbind_set(struct net *,
  42						     const struct svc_program *,
  43						     u32, int,
  44						     unsigned short,
  45						     unsigned short);
  46static __be32			nfsd_acl_init_request(struct svc_rqst *,
  47						const struct svc_program *,
  48						struct svc_process_info *);
  49#endif
  50static int			nfsd_rpcbind_set(struct net *,
  51						 const struct svc_program *,
  52						 u32, int,
  53						 unsigned short,
  54						 unsigned short);
  55static __be32			nfsd_init_request(struct svc_rqst *,
  56						const struct svc_program *,
  57						struct svc_process_info *);
  58
  59/*
  60 * nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and some members
  61 * of the svc_serv struct such as ->sv_temp_socks and ->sv_permsocks.
  62 *
  63 * Finally, the nfsd_mutex also protects some of the global variables that are
  64 * accessed when nfsd starts and that are settable via the write_* routines in
  65 * nfsctl.c. In particular:
  66 *
  67 *	user_recovery_dirname
  68 *	user_lease_time
  69 *	nfsd_versions
  70 */
  71DEFINE_MUTEX(nfsd_mutex);
  72
  73#if IS_ENABLED(CONFIG_NFS_LOCALIO)
  74static const struct svc_version *localio_versions[] = {
  75	[1] = &localio_version1,
  76};
  77
  78#define NFSD_LOCALIO_NRVERS		ARRAY_SIZE(localio_versions)
  79
  80#endif /* CONFIG_NFS_LOCALIO */
  81
  82#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
  83static const struct svc_version *nfsd_acl_version[] = {
  84# if defined(CONFIG_NFSD_V2_ACL)
  85	[2] = &nfsd_acl_version2,
  86# endif
  87# if defined(CONFIG_NFSD_V3_ACL)
  88	[3] = &nfsd_acl_version3,
  89# endif
  90};
  91
  92#define NFSD_ACL_MINVERS	2
  93#define NFSD_ACL_NRVERS		ARRAY_SIZE(nfsd_acl_version)
  94
  95#endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
  96
  97static const struct svc_version *nfsd_version[NFSD_MAXVERS+1] = {
  98#if defined(CONFIG_NFSD_V2)
  99	[2] = &nfsd_version2,
 100#endif
 101	[3] = &nfsd_version3,
 102#if defined(CONFIG_NFSD_V4)
 103	[4] = &nfsd_version4,
 104#endif
 105};
 106
 107struct svc_program		nfsd_programs[] = {
 108	{
 109	.pg_prog		= NFS_PROGRAM,		/* program number */
 110	.pg_nvers		= NFSD_MAXVERS+1,	/* nr of entries in nfsd_version */
 111	.pg_vers		= nfsd_version,		/* version table */
 112	.pg_name		= "nfsd",		/* program name */
 113	.pg_class		= "nfsd",		/* authentication class */
 114	.pg_authenticate	= svc_set_client,	/* export authentication */
 115	.pg_init_request	= nfsd_init_request,
 116	.pg_rpcbind_set		= nfsd_rpcbind_set,
 117	},
 118#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 119	{
 120	.pg_prog		= NFS_ACL_PROGRAM,
 121	.pg_nvers		= NFSD_ACL_NRVERS,
 122	.pg_vers		= nfsd_acl_version,
 123	.pg_name		= "nfsacl",
 124	.pg_class		= "nfsd",
 125	.pg_authenticate	= svc_set_client,
 126	.pg_init_request	= nfsd_acl_init_request,
 127	.pg_rpcbind_set		= nfsd_acl_rpcbind_set,
 128	},
 129#endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
 130#if IS_ENABLED(CONFIG_NFS_LOCALIO)
 131	{
 132	.pg_prog		= NFS_LOCALIO_PROGRAM,
 133	.pg_nvers		= NFSD_LOCALIO_NRVERS,
 134	.pg_vers		= localio_versions,
 135	.pg_name		= "nfslocalio",
 136	.pg_class		= "nfsd",
 137	.pg_authenticate	= svc_set_client,
 138	.pg_init_request	= svc_generic_init_request,
 139	.pg_rpcbind_set		= svc_generic_rpcbind_set,
 140	}
 141#endif /* CONFIG_NFS_LOCALIO */
 142};
 143
 144bool nfsd_support_version(int vers)
 145{
 146	if (vers >= NFSD_MINVERS && vers <= NFSD_MAXVERS)
 147		return nfsd_version[vers] != NULL;
 148	return false;
 149}
 150
 151int nfsd_vers(struct nfsd_net *nn, int vers, enum vers_op change)
 152{
 153	if (vers < NFSD_MINVERS || vers > NFSD_MAXVERS)
 154		return 0;
 155	switch(change) {
 156	case NFSD_SET:
 157		nn->nfsd_versions[vers] = nfsd_support_version(vers);
 158		break;
 159	case NFSD_CLEAR:
 160		nn->nfsd_versions[vers] = false;
 161		break;
 162	case NFSD_TEST:
 163		return nn->nfsd_versions[vers];
 164	case NFSD_AVAIL:
 165		return nfsd_support_version(vers);
 166	}
 167	return 0;
 168}
 169
 170static void
 171nfsd_adjust_nfsd_versions4(struct nfsd_net *nn)
 172{
 173	unsigned i;
 174
 175	for (i = 0; i <= NFSD_SUPPORTED_MINOR_VERSION; i++) {
 176		if (nn->nfsd4_minorversions[i])
 177			return;
 178	}
 179	nfsd_vers(nn, 4, NFSD_CLEAR);
 180}
 181
 182int nfsd_minorversion(struct nfsd_net *nn, u32 minorversion, enum vers_op change)
 183{
 184	if (minorversion > NFSD_SUPPORTED_MINOR_VERSION &&
 185	    change != NFSD_AVAIL)
 186		return -1;
 187
 188	switch(change) {
 189	case NFSD_SET:
 190		nfsd_vers(nn, 4, NFSD_SET);
 191		nn->nfsd4_minorversions[minorversion] =
 192			nfsd_vers(nn, 4, NFSD_TEST);
 193		break;
 194	case NFSD_CLEAR:
 195		nn->nfsd4_minorversions[minorversion] = false;
 196		nfsd_adjust_nfsd_versions4(nn);
 197		break;
 198	case NFSD_TEST:
 199		return nn->nfsd4_minorversions[minorversion];
 200	case NFSD_AVAIL:
 201		return minorversion <= NFSD_SUPPORTED_MINOR_VERSION &&
 202			nfsd_vers(nn, 4, NFSD_AVAIL);
 203	}
 204	return 0;
 205}
 206
 207bool nfsd_net_try_get(struct net *net) __must_hold(rcu)
 208{
 209	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 210
 211	return (nn && percpu_ref_tryget_live(&nn->nfsd_net_ref));
 212}
 213
 214void nfsd_net_put(struct net *net) __must_hold(rcu)
 215{
 216	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 217
 218	percpu_ref_put(&nn->nfsd_net_ref);
 219}
 220
 221static void nfsd_net_done(struct percpu_ref *ref)
 222{
 223	struct nfsd_net *nn = container_of(ref, struct nfsd_net, nfsd_net_ref);
 224
 225	complete(&nn->nfsd_net_confirm_done);
 226}
 227
 228static void nfsd_net_free(struct percpu_ref *ref)
 229{
 230	struct nfsd_net *nn = container_of(ref, struct nfsd_net, nfsd_net_ref);
 231
 232	complete(&nn->nfsd_net_free_done);
 233}
 234
 235/*
 236 * Maximum number of nfsd processes
 237 */
 238#define	NFSD_MAXSERVS		8192
 239
 240int nfsd_nrthreads(struct net *net)
 241{
 242	int rv = 0;
 243	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 244
 245	mutex_lock(&nfsd_mutex);
 246	if (nn->nfsd_serv)
 247		rv = nn->nfsd_serv->sv_nrthreads;
 248	mutex_unlock(&nfsd_mutex);
 249	return rv;
 250}
 251
 252static int nfsd_users = 0;
 253
 254static int nfsd_startup_generic(void)
 255{
 256	int ret;
 257
 258	if (nfsd_users++)
 259		return 0;
 260
 261	ret = nfsd_file_cache_init();
 262	if (ret)
 263		goto dec_users;
 264
 265	ret = nfs4_state_start();
 266	if (ret)
 267		goto out_file_cache;
 268	return 0;
 269
 270out_file_cache:
 271	nfsd_file_cache_shutdown();
 272dec_users:
 273	nfsd_users--;
 274	return ret;
 275}
 276
 277static void nfsd_shutdown_generic(void)
 278{
 279	if (--nfsd_users)
 280		return;
 281
 282	nfs4_state_shutdown();
 283	nfsd_file_cache_shutdown();
 284}
 285
 286static bool nfsd_needs_lockd(struct nfsd_net *nn)
 287{
 288	return nfsd_vers(nn, 2, NFSD_TEST) || nfsd_vers(nn, 3, NFSD_TEST);
 289}
 290
 291/**
 292 * nfsd_copy_write_verifier - Atomically copy a write verifier
 293 * @verf: buffer in which to receive the verifier cookie
 294 * @nn: NFS net namespace
 295 *
 296 * This function provides a wait-free mechanism for copying the
 297 * namespace's write verifier without tearing it.
 298 */
 299void nfsd_copy_write_verifier(__be32 verf[2], struct nfsd_net *nn)
 300{
 301	unsigned int seq;
 302
 303	do {
 304		seq = read_seqbegin(&nn->writeverf_lock);
 305		memcpy(verf, nn->writeverf, sizeof(nn->writeverf));
 306	} while (read_seqretry(&nn->writeverf_lock, seq));
 307}
 308
 309static void nfsd_reset_write_verifier_locked(struct nfsd_net *nn)
 310{
 311	struct timespec64 now;
 312	u64 verf;
 313
 314	/*
 315	 * Because the time value is hashed, y2038 time_t overflow
 316	 * is irrelevant in this usage.
 317	 */
 318	ktime_get_raw_ts64(&now);
 319	verf = siphash_2u64(now.tv_sec, now.tv_nsec, &nn->siphash_key);
 320	memcpy(nn->writeverf, &verf, sizeof(nn->writeverf));
 321}
 322
 323/**
 324 * nfsd_reset_write_verifier - Generate a new write verifier
 325 * @nn: NFS net namespace
 326 *
 327 * This function updates the ->writeverf field of @nn. This field
 328 * contains an opaque cookie that, according to Section 18.32.3 of
 329 * RFC 8881, "the client can use to determine whether a server has
 330 * changed instance state (e.g., server restart) between a call to
 331 * WRITE and a subsequent call to either WRITE or COMMIT.  This
 332 * cookie MUST be unchanged during a single instance of the NFSv4.1
 333 * server and MUST be unique between instances of the NFSv4.1
 334 * server."
 335 */
 336void nfsd_reset_write_verifier(struct nfsd_net *nn)
 337{
 338	write_seqlock(&nn->writeverf_lock);
 339	nfsd_reset_write_verifier_locked(nn);
 340	write_sequnlock(&nn->writeverf_lock);
 341}
 342
 343/*
 344 * Crank up a set of per-namespace resources for a new NFSD instance,
 345 * including lockd, a duplicate reply cache, an open file cache
 346 * instance, and a cache of NFSv4 state objects.
 347 */
 348static int nfsd_startup_net(struct net *net, const struct cred *cred)
 349{
 350	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 351	int ret;
 352
 353	if (nn->nfsd_net_up)
 354		return 0;
 355
 356	ret = nfsd_startup_generic();
 357	if (ret)
 358		return ret;
 359
 360	if (list_empty(&nn->nfsd_serv->sv_permsocks)) {
 361		pr_warn("NFSD: Failed to start, no listeners configured.\n");
 362		ret = -EIO;
 363		goto out_socks;
 364	}
 365
 366	if (nfsd_needs_lockd(nn) && !nn->lockd_up) {
 367		ret = lockd_up(net, cred);
 368		if (ret)
 369			goto out_socks;
 370		nn->lockd_up = true;
 371	}
 372
 373	ret = nfsd_file_cache_start_net(net);
 374	if (ret)
 375		goto out_lockd;
 376
 377	ret = nfsd_reply_cache_init(nn);
 378	if (ret)
 379		goto out_filecache;
 380
 381#ifdef CONFIG_NFSD_V4_2_INTER_SSC
 382	nfsd4_ssc_init_umount_work(nn);
 383#endif
 384	ret = nfs4_state_start_net(net);
 385	if (ret)
 386		goto out_reply_cache;
 387
 388	nn->nfsd_net_up = true;
 389	return 0;
 390
 391out_reply_cache:
 392	nfsd_reply_cache_shutdown(nn);
 393out_filecache:
 394	nfsd_file_cache_shutdown_net(net);
 395out_lockd:
 396	if (nn->lockd_up) {
 397		lockd_down(net);
 398		nn->lockd_up = false;
 399	}
 400out_socks:
 401	nfsd_shutdown_generic();
 402	return ret;
 403}
 404
 405static void nfsd_shutdown_net(struct net *net)
 406{
 407	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 408
 409	if (nn->nfsd_net_up) {
 410		percpu_ref_kill_and_confirm(&nn->nfsd_net_ref, nfsd_net_done);
 411		wait_for_completion(&nn->nfsd_net_confirm_done);
 412
 413		nfsd_export_flush(net);
 414		nfs4_state_shutdown_net(net);
 415		nfsd_reply_cache_shutdown(nn);
 416		nfsd_file_cache_shutdown_net(net);
 417		if (nn->lockd_up) {
 418			lockd_down(net);
 419			nn->lockd_up = false;
 420		}
 421		wait_for_completion(&nn->nfsd_net_free_done);
 422	}
 423
 424	percpu_ref_exit(&nn->nfsd_net_ref);
 425
 426	if (nn->nfsd_net_up)
 427		nfsd_shutdown_generic();
 428	nn->nfsd_net_up = false;
 429}
 430
 431static DEFINE_SPINLOCK(nfsd_notifier_lock);
 432static int nfsd_inetaddr_event(struct notifier_block *this, unsigned long event,
 433	void *ptr)
 434{
 435	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
 436	struct net_device *dev = ifa->ifa_dev->dev;
 437	struct net *net = dev_net(dev);
 438	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 439	struct sockaddr_in sin;
 440
 441	if (event != NETDEV_DOWN || !nn->nfsd_serv)
 442		goto out;
 443
 444	spin_lock(&nfsd_notifier_lock);
 445	if (nn->nfsd_serv) {
 446		dprintk("nfsd_inetaddr_event: removed %pI4\n", &ifa->ifa_local);
 447		sin.sin_family = AF_INET;
 448		sin.sin_addr.s_addr = ifa->ifa_local;
 449		svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin);
 450	}
 451	spin_unlock(&nfsd_notifier_lock);
 452
 453out:
 454	return NOTIFY_DONE;
 455}
 456
 457static struct notifier_block nfsd_inetaddr_notifier = {
 458	.notifier_call = nfsd_inetaddr_event,
 459};
 460
 461#if IS_ENABLED(CONFIG_IPV6)
 462static int nfsd_inet6addr_event(struct notifier_block *this,
 463	unsigned long event, void *ptr)
 464{
 465	struct inet6_ifaddr *ifa = (struct inet6_ifaddr *)ptr;
 466	struct net_device *dev = ifa->idev->dev;
 467	struct net *net = dev_net(dev);
 468	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 469	struct sockaddr_in6 sin6;
 470
 471	if (event != NETDEV_DOWN || !nn->nfsd_serv)
 472		goto out;
 473
 474	spin_lock(&nfsd_notifier_lock);
 475	if (nn->nfsd_serv) {
 476		dprintk("nfsd_inet6addr_event: removed %pI6\n", &ifa->addr);
 477		sin6.sin6_family = AF_INET6;
 478		sin6.sin6_addr = ifa->addr;
 479		if (ipv6_addr_type(&sin6.sin6_addr) & IPV6_ADDR_LINKLOCAL)
 480			sin6.sin6_scope_id = ifa->idev->dev->ifindex;
 481		svc_age_temp_xprts_now(nn->nfsd_serv, (struct sockaddr *)&sin6);
 482	}
 483	spin_unlock(&nfsd_notifier_lock);
 484
 485out:
 486	return NOTIFY_DONE;
 487}
 488
 489static struct notifier_block nfsd_inet6addr_notifier = {
 490	.notifier_call = nfsd_inet6addr_event,
 491};
 492#endif
 493
 494/* Only used under nfsd_mutex, so this atomic may be overkill: */
 495static atomic_t nfsd_notifier_refcount = ATOMIC_INIT(0);
 496
 497/**
 498 * nfsd_destroy_serv - tear down NFSD's svc_serv for a namespace
 499 * @net: network namespace the NFS service is associated with
 500 */
 501void nfsd_destroy_serv(struct net *net)
 502{
 503	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 504	struct svc_serv *serv = nn->nfsd_serv;
 505
 506	lockdep_assert_held(&nfsd_mutex);
 507
 508	spin_lock(&nfsd_notifier_lock);
 509	nn->nfsd_serv = NULL;
 510	spin_unlock(&nfsd_notifier_lock);
 511
 512	/* check if the notifier still has clients */
 513	if (atomic_dec_return(&nfsd_notifier_refcount) == 0) {
 514		unregister_inetaddr_notifier(&nfsd_inetaddr_notifier);
 515#if IS_ENABLED(CONFIG_IPV6)
 516		unregister_inet6addr_notifier(&nfsd_inet6addr_notifier);
 517#endif
 518	}
 519
 520	/*
 521	 * write_ports can create the server without actually starting
 522	 * any threads.  If we get shut down before any threads are
 523	 * started, then nfsd_destroy_serv will be run before any of this
 524	 * other initialization has been done except the rpcb information.
 525	 */
 526	svc_xprt_destroy_all(serv, net, true);
 527	nfsd_shutdown_net(net);
 528	svc_destroy(&serv);
 529}
 530
 531void nfsd_reset_versions(struct nfsd_net *nn)
 532{
 533	int i;
 534
 535	for (i = 0; i <= NFSD_MAXVERS; i++)
 536		if (nfsd_vers(nn, i, NFSD_TEST))
 537			return;
 538
 539	for (i = 0; i <= NFSD_MAXVERS; i++)
 540		if (i != 4)
 541			nfsd_vers(nn, i, NFSD_SET);
 542		else {
 543			int minor = 0;
 544			while (nfsd_minorversion(nn, minor, NFSD_SET) >= 0)
 545				minor++;
 546		}
 547}
 548
 549static int nfsd_get_default_max_blksize(void)
 550{
 551	struct sysinfo i;
 552	unsigned long long target;
 553	unsigned long ret;
 554
 555	si_meminfo(&i);
 556	target = (i.totalram - i.totalhigh) << PAGE_SHIFT;
 557	/*
 558	 * Aim for 1/4096 of memory per thread This gives 1MB on 4Gig
 559	 * machines, but only uses 32K on 128M machines.  Bottom out at
 560	 * 8K on 32M and smaller.  Of course, this is only a default.
 561	 */
 562	target >>= 12;
 563
 564	ret = NFSSVC_DEFBLKSIZE;
 565	while (ret > target && ret >= 8*1024*2)
 566		ret /= 2;
 567	return ret;
 568}
 569
 570void nfsd_shutdown_threads(struct net *net)
 571{
 572	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 573	struct svc_serv *serv;
 574
 575	mutex_lock(&nfsd_mutex);
 576	serv = nn->nfsd_serv;
 577	if (serv == NULL) {
 578		mutex_unlock(&nfsd_mutex);
 579		return;
 580	}
 581
 582	/* Kill outstanding nfsd threads */
 583	svc_set_num_threads(serv, NULL, 0);
 584	nfsd_destroy_serv(net);
 585	mutex_unlock(&nfsd_mutex);
 586}
 587
 588struct svc_rqst *nfsd_current_rqst(void)
 589{
 590	if (kthread_func(current) == nfsd)
 591		return kthread_data(current);
 592	return NULL;
 593}
 594
 595int nfsd_create_serv(struct net *net)
 596{
 597	int error;
 598	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 599	struct svc_serv *serv;
 600
 601	WARN_ON(!mutex_is_locked(&nfsd_mutex));
 602	if (nn->nfsd_serv)
 603		return 0;
 604
 605	error = percpu_ref_init(&nn->nfsd_net_ref, nfsd_net_free,
 606				0, GFP_KERNEL);
 607	if (error)
 608		return error;
 609	init_completion(&nn->nfsd_net_free_done);
 610	init_completion(&nn->nfsd_net_confirm_done);
 611
 612	if (nfsd_max_blksize == 0)
 613		nfsd_max_blksize = nfsd_get_default_max_blksize();
 614	nfsd_reset_versions(nn);
 615	serv = svc_create_pooled(nfsd_programs, ARRAY_SIZE(nfsd_programs),
 616				 &nn->nfsd_svcstats,
 617				 nfsd_max_blksize, nfsd);
 618	if (serv == NULL) {
 619		percpu_ref_exit(&nn->nfsd_net_ref);
 620		return -ENOMEM;
 621	}
 622
 623	error = svc_bind(serv, net);
 624	if (error < 0) {
 625		svc_destroy(&serv);
 626		percpu_ref_exit(&nn->nfsd_net_ref);
 627		return error;
 628	}
 629	spin_lock(&nfsd_notifier_lock);
 630	nn->nfsd_serv = serv;
 631	spin_unlock(&nfsd_notifier_lock);
 632
 633	/* check if the notifier is already set */
 634	if (atomic_inc_return(&nfsd_notifier_refcount) == 1) {
 635		register_inetaddr_notifier(&nfsd_inetaddr_notifier);
 636#if IS_ENABLED(CONFIG_IPV6)
 637		register_inet6addr_notifier(&nfsd_inet6addr_notifier);
 638#endif
 639	}
 640	nfsd_reset_write_verifier(nn);
 641	return 0;
 642}
 643
 644int nfsd_nrpools(struct net *net)
 645{
 646	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 647
 648	if (nn->nfsd_serv == NULL)
 649		return 0;
 650	else
 651		return nn->nfsd_serv->sv_nrpools;
 652}
 653
 654int nfsd_get_nrthreads(int n, int *nthreads, struct net *net)
 655{
 656	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 657	struct svc_serv *serv = nn->nfsd_serv;
 658	int i;
 659
 660	if (serv)
 661		for (i = 0; i < serv->sv_nrpools && i < n; i++)
 662			nthreads[i] = serv->sv_pools[i].sp_nrthreads;
 663	return 0;
 664}
 665
 666/**
 667 * nfsd_set_nrthreads - set the number of running threads in the net's service
 668 * @n: number of array members in @nthreads
 669 * @nthreads: array of thread counts for each pool
 670 * @net: network namespace to operate within
 671 *
 672 * This function alters the number of running threads for the given network
 673 * namespace in each pool. If passed an array longer then the number of pools
 674 * the extra pool settings are ignored. If passed an array shorter than the
 675 * number of pools, the missing values are interpreted as 0's.
 676 *
 677 * Returns 0 on success or a negative errno on error.
 678 */
 679int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
 680{
 681	int i = 0;
 682	int tot = 0;
 683	int err = 0;
 684	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 685
 686	lockdep_assert_held(&nfsd_mutex);
 687
 688	if (nn->nfsd_serv == NULL || n <= 0)
 689		return 0;
 690
 691	/*
 692	 * Special case: When n == 1, pass in NULL for the pool, so that the
 693	 * change is distributed equally among them.
 694	 */
 695	if (n == 1)
 696		return svc_set_num_threads(nn->nfsd_serv, NULL, nthreads[0]);
 697
 698	if (n > nn->nfsd_serv->sv_nrpools)
 699		n = nn->nfsd_serv->sv_nrpools;
 700
 701	/* enforce a global maximum number of threads */
 702	tot = 0;
 703	for (i = 0; i < n; i++) {
 704		nthreads[i] = min(nthreads[i], NFSD_MAXSERVS);
 705		tot += nthreads[i];
 706	}
 707	if (tot > NFSD_MAXSERVS) {
 708		/* total too large: scale down requested numbers */
 709		for (i = 0; i < n && tot > 0; i++) {
 710			int new = nthreads[i] * NFSD_MAXSERVS / tot;
 711			tot -= (nthreads[i] - new);
 712			nthreads[i] = new;
 713		}
 714		for (i = 0; i < n && tot > 0; i++) {
 715			nthreads[i]--;
 716			tot--;
 717		}
 718	}
 719
 720	/* apply the new numbers */
 721	for (i = 0; i < n; i++) {
 722		err = svc_set_num_threads(nn->nfsd_serv,
 723					  &nn->nfsd_serv->sv_pools[i],
 724					  nthreads[i]);
 725		if (err)
 726			goto out;
 727	}
 728
 729	/* Anything undefined in array is considered to be 0 */
 730	for (i = n; i < nn->nfsd_serv->sv_nrpools; ++i) {
 731		err = svc_set_num_threads(nn->nfsd_serv,
 732					  &nn->nfsd_serv->sv_pools[i],
 733					  0);
 734		if (err)
 735			goto out;
 736	}
 737out:
 738	return err;
 739}
 740
 741/**
 742 * nfsd_svc: start up or shut down the nfsd server
 743 * @n: number of array members in @nthreads
 744 * @nthreads: array of thread counts for each pool
 745 * @net: network namespace to operate within
 746 * @cred: credentials to use for xprt creation
 747 * @scope: server scope value (defaults to nodename)
 748 *
 749 * Adjust the number of threads in each pool and return the new
 750 * total number of threads in the service.
 751 */
 752int
 753nfsd_svc(int n, int *nthreads, struct net *net, const struct cred *cred, const char *scope)
 754{
 755	int	error;
 756	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 757	struct svc_serv *serv;
 758
 759	lockdep_assert_held(&nfsd_mutex);
 760
 761	dprintk("nfsd: creating service\n");
 762
 763	strscpy(nn->nfsd_name, scope ? scope : utsname()->nodename,
 764		sizeof(nn->nfsd_name));
 765
 766	error = nfsd_create_serv(net);
 767	if (error)
 768		goto out;
 769	serv = nn->nfsd_serv;
 770
 771	error = nfsd_startup_net(net, cred);
 772	if (error)
 773		goto out_put;
 774	error = nfsd_set_nrthreads(n, nthreads, net);
 775	if (error)
 776		goto out_put;
 777	error = serv->sv_nrthreads;
 778out_put:
 779	if (serv->sv_nrthreads == 0)
 780		nfsd_destroy_serv(net);
 781out:
 782	return error;
 783}
 784
 785#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 786static bool
 787nfsd_support_acl_version(int vers)
 788{
 789	if (vers >= NFSD_ACL_MINVERS && vers < NFSD_ACL_NRVERS)
 790		return nfsd_acl_version[vers] != NULL;
 791	return false;
 792}
 793
 794static int
 795nfsd_acl_rpcbind_set(struct net *net, const struct svc_program *progp,
 796		     u32 version, int family, unsigned short proto,
 797		     unsigned short port)
 798{
 799	if (!nfsd_support_acl_version(version) ||
 800	    !nfsd_vers(net_generic(net, nfsd_net_id), version, NFSD_TEST))
 801		return 0;
 802	return svc_generic_rpcbind_set(net, progp, version, family,
 803			proto, port);
 804}
 805
 806static __be32
 807nfsd_acl_init_request(struct svc_rqst *rqstp,
 808		      const struct svc_program *progp,
 809		      struct svc_process_info *ret)
 810{
 811	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 812	int i;
 813
 814	if (likely(nfsd_support_acl_version(rqstp->rq_vers) &&
 815	    nfsd_vers(nn, rqstp->rq_vers, NFSD_TEST)))
 816		return svc_generic_init_request(rqstp, progp, ret);
 817
 818	ret->mismatch.lovers = NFSD_ACL_NRVERS;
 819	for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++) {
 820		if (nfsd_support_acl_version(rqstp->rq_vers) &&
 821		    nfsd_vers(nn, i, NFSD_TEST)) {
 822			ret->mismatch.lovers = i;
 823			break;
 824		}
 825	}
 826	if (ret->mismatch.lovers == NFSD_ACL_NRVERS)
 827		return rpc_prog_unavail;
 828	ret->mismatch.hivers = NFSD_ACL_MINVERS;
 829	for (i = NFSD_ACL_NRVERS - 1; i >= NFSD_ACL_MINVERS; i--) {
 830		if (nfsd_support_acl_version(rqstp->rq_vers) &&
 831		    nfsd_vers(nn, i, NFSD_TEST)) {
 832			ret->mismatch.hivers = i;
 833			break;
 834		}
 835	}
 836	return rpc_prog_mismatch;
 837}
 838#endif
 839
 840static int
 841nfsd_rpcbind_set(struct net *net, const struct svc_program *progp,
 842		 u32 version, int family, unsigned short proto,
 843		 unsigned short port)
 844{
 845	if (!nfsd_vers(net_generic(net, nfsd_net_id), version, NFSD_TEST))
 846		return 0;
 847	return svc_generic_rpcbind_set(net, progp, version, family,
 848			proto, port);
 849}
 850
 851static __be32
 852nfsd_init_request(struct svc_rqst *rqstp,
 853		  const struct svc_program *progp,
 854		  struct svc_process_info *ret)
 855{
 856	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 857	int i;
 858
 859	if (likely(nfsd_vers(nn, rqstp->rq_vers, NFSD_TEST)))
 860		return svc_generic_init_request(rqstp, progp, ret);
 861
 862	ret->mismatch.lovers = NFSD_MAXVERS + 1;
 863	for (i = NFSD_MINVERS; i <= NFSD_MAXVERS; i++) {
 864		if (nfsd_vers(nn, i, NFSD_TEST)) {
 865			ret->mismatch.lovers = i;
 866			break;
 867		}
 868	}
 869	if (ret->mismatch.lovers > NFSD_MAXVERS)
 870		return rpc_prog_unavail;
 871	ret->mismatch.hivers = NFSD_MINVERS;
 872	for (i = NFSD_MAXVERS; i >= NFSD_MINVERS; i--) {
 873		if (nfsd_vers(nn, i, NFSD_TEST)) {
 874			ret->mismatch.hivers = i;
 875			break;
 876		}
 877	}
 878	return rpc_prog_mismatch;
 879}
 880
 881/*
 882 * This is the NFS server kernel thread
 883 */
 884static int
 885nfsd(void *vrqstp)
 886{
 887	struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
 888	struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list);
 889	struct net *net = perm_sock->xpt_net;
 890	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 891
 892	/* At this point, the thread shares current->fs
 893	 * with the init process. We need to create files with the
 894	 * umask as defined by the client instead of init's umask.
 895	 */
 896	svc_thread_init_status(rqstp, unshare_fs_struct());
 897
 898	current->fs->umask = 0;
 899
 900	atomic_inc(&nfsd_th_cnt);
 901
 902	set_freezable();
 903
 904	/*
 905	 * The main request loop
 906	 */
 907	while (!svc_thread_should_stop(rqstp)) {
 908		svc_recv(rqstp);
 909		nfsd_file_net_dispose(nn);
 910	}
 911
 912	atomic_dec(&nfsd_th_cnt);
 913
 914	/* Release the thread */
 915	svc_exit_thread(rqstp);
 916	return 0;
 917}
 918
 919/**
 920 * nfsd_dispatch - Process an NFS or NFSACL or LOCALIO Request
 921 * @rqstp: incoming request
 922 *
 923 * This RPC dispatcher integrates the NFS server's duplicate reply cache.
 924 *
 925 * Return values:
 926 *  %0: Processing complete; do not send a Reply
 927 *  %1: Processing complete; send Reply in rqstp->rq_res
 928 */
 929int nfsd_dispatch(struct svc_rqst *rqstp)
 930{
 931	const struct svc_procedure *proc = rqstp->rq_procinfo;
 932	__be32 *statp = rqstp->rq_accept_statp;
 933	struct nfsd_cacherep *rp;
 934	unsigned int start, len;
 935	__be32 *nfs_reply;
 936
 937	/*
 938	 * Give the xdr decoder a chance to change this if it wants
 939	 * (necessary in the NFSv4.0 compound case)
 940	 */
 941	rqstp->rq_cachetype = proc->pc_cachetype;
 942
 943	/*
 944	 * ->pc_decode advances the argument stream past the NFS
 945	 * Call header, so grab the header's starting location and
 946	 * size now for the call to nfsd_cache_lookup().
 947	 */
 948	start = xdr_stream_pos(&rqstp->rq_arg_stream);
 949	len = xdr_stream_remaining(&rqstp->rq_arg_stream);
 950	if (!proc->pc_decode(rqstp, &rqstp->rq_arg_stream))
 951		goto out_decode_err;
 952
 953	/*
 954	 * Release rq_status_counter setting it to an odd value after the rpc
 955	 * request has been properly parsed. rq_status_counter is used to
 956	 * notify the consumers if the rqstp fields are stable
 957	 * (rq_status_counter is odd) or not meaningful (rq_status_counter
 958	 * is even).
 959	 */
 960	smp_store_release(&rqstp->rq_status_counter, rqstp->rq_status_counter | 1);
 961
 962	rp = NULL;
 963	switch (nfsd_cache_lookup(rqstp, start, len, &rp)) {
 964	case RC_DOIT:
 965		break;
 966	case RC_REPLY:
 967		goto out_cached_reply;
 968	case RC_DROPIT:
 969		goto out_dropit;
 970	}
 971
 972	nfs_reply = xdr_inline_decode(&rqstp->rq_res_stream, 0);
 973	*statp = proc->pc_func(rqstp);
 974	if (test_bit(RQ_DROPME, &rqstp->rq_flags))
 975		goto out_update_drop;
 976
 977	if (!proc->pc_encode(rqstp, &rqstp->rq_res_stream))
 978		goto out_encode_err;
 979
 980	/*
 981	 * Release rq_status_counter setting it to an even value after the rpc
 982	 * request has been properly processed.
 983	 */
 984	smp_store_release(&rqstp->rq_status_counter, rqstp->rq_status_counter + 1);
 985
 986	nfsd_cache_update(rqstp, rp, rqstp->rq_cachetype, nfs_reply);
 987out_cached_reply:
 988	return 1;
 989
 990out_decode_err:
 991	trace_nfsd_garbage_args_err(rqstp);
 992	*statp = rpc_garbage_args;
 993	return 1;
 994
 995out_update_drop:
 996	nfsd_cache_update(rqstp, rp, RC_NOCACHE, NULL);
 997out_dropit:
 998	return 0;
 999
1000out_encode_err:
1001	trace_nfsd_cant_encode_err(rqstp);
1002	nfsd_cache_update(rqstp, rp, RC_NOCACHE, NULL);
1003	*statp = rpc_system_err;
1004	return 1;
1005}
1006
1007/**
1008 * nfssvc_decode_voidarg - Decode void arguments
1009 * @rqstp: Server RPC transaction context
1010 * @xdr: XDR stream positioned at arguments to decode
1011 *
1012 * Return values:
1013 *   %false: Arguments were not valid
1014 *   %true: Decoding was successful
1015 */
1016bool nfssvc_decode_voidarg(struct svc_rqst *rqstp, struct xdr_stream *xdr)
1017{
1018	return true;
1019}
1020
1021/**
1022 * nfssvc_encode_voidres - Encode void results
1023 * @rqstp: Server RPC transaction context
1024 * @xdr: XDR stream into which to encode results
1025 *
1026 * Return values:
1027 *   %false: Local error while encoding
1028 *   %true: Encoding was successful
1029 */
1030bool nfssvc_encode_voidres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
1031{
1032	return true;
1033}