fs/nfs/fs_context.c

/* NFS mount handling.
 *
 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * Split from fs/nfs/super.c:
 *
 *  Copyright (C) 1992  Rick Sladkey
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/nfs4_mount.h>
#include "nfs.h"
#include "internal.h"

#define NFSDBG_FACILITY		NFSDBG_MOUNT

#if IS_ENABLED(CONFIG_NFS_V3)
#define NFS_DEFAULT_VERSION 3
#else
#define NFS_DEFAULT_VERSION 2
#endif

enum nfs_param {
	Opt_ac,
	Opt_acdirmax,
	Opt_acdirmin,
	Opt_acl,
	Opt_acregmax,
	Opt_acregmin,
	Opt_actimeo,
	Opt_addr,
	Opt_bg,
	Opt_bsize,
	Opt_clientaddr,
	Opt_cto,
	Opt_fg,
	Opt_fscache,
	Opt_hard,
	Opt_intr,
	Opt_local_lock,
	Opt_lock,
	Opt_lookupcache,
	Opt_migration,
	Opt_minorversion,
	Opt_mountaddr,
	Opt_mounthost,
	Opt_mountport,
	Opt_mountproto,
	Opt_mountvers,
	Opt_namelen,
	Opt_port,
	Opt_posix,
	Opt_proto,
	Opt_rdirplus,
	Opt_rdma,
	Opt_resvport,
	Opt_retrans,
	Opt_retry,
	Opt_rsize,
	Opt_sec,
	Opt_sharecache,
	Opt_sloppy,
	Opt_soft,
	Opt_source,
	Opt_tcp,
	Opt_timeo,
	Opt_udp,
	Opt_v,
	Opt_vers,
	Opt_wsize,
	nr__nfs_params
};

static const struct fs_parameter_spec nfs_param_specs[nr__nfs_params] = {
	[Opt_ac]		= { fs_param_is_flag, fs_param_neg_with_no },
	[Opt_acdirmax]		= { fs_param_is_u32 },
	[Opt_acdirmin]		= { fs_param_is_u32 },
	[Opt_acl]		= { fs_param_is_flag, fs_param_neg_with_no },
	[Opt_acregmax]		= { fs_param_is_u32 },
	[Opt_acregmin]		= { fs_param_is_u32 },
	[Opt_actimeo]		= { fs_param_is_u32 },
	[Opt_addr]		= { fs_param_is_string },
	[Opt_bg]		= { fs_param_is_flag },
	[Opt_bsize]		= { fs_param_is_u32 },
	[Opt_clientaddr]	= { fs_param_is_string },
	[Opt_cto]		= { fs_param_is_flag, fs_param_neg_with_no },
	[Opt_fg]		= { fs_param_is_flag },
	[Opt_fscache]		= { fs_param_is_string, fs_param_v_optional | fs_param_neg_with_no },
	[Opt_hard]		= { fs_param_is_flag },
	[Opt_intr]		= { fs_param_is_flag, fs_param_neg_with_no | fs_param_deprecated },
	[Opt_local_lock]	= { fs_param_is_enum },
	[Opt_lock]		= { fs_param_is_flag, fs_param_neg_with_no },
	[Opt_lookupcache]	= { fs_param_is_enum },
	[Opt_migration]		= { fs_param_is_flag, fs_param_neg_with_no },
	[Opt_minorversion]	= { fs_param_is_u32 },
	[Opt_mountaddr]		= { fs_param_is_string },
	[Opt_mounthost]		= { fs_param_is_string },
	[Opt_mountport]		= { fs_param_is_u32 },
	[Opt_mountproto]	= { fs_param_is_string },
	[Opt_mountvers]		= { fs_param_is_u32 },
	[Opt_namelen]		= { fs_param_is_u32 },
	[Opt_port]		= { fs_param_is_u32 },
	[Opt_posix]		= { fs_param_is_flag, fs_param_neg_with_no },
	[Opt_proto]		= { fs_param_is_string },
	[Opt_rdirplus]		= { fs_param_is_flag, fs_param_neg_with_no },
	[Opt_rdma]		= { fs_param_is_flag },
	[Opt_resvport]		= { fs_param_is_flag, fs_param_neg_with_no },
	[Opt_retrans]		= { fs_param_is_string },
	[Opt_retry]		= { fs_param_is_string },
	[Opt_rsize]		= { fs_param_is_u32 },
	[Opt_sec]		= { fs_param_is_string },
	[Opt_sharecache]	= { fs_param_is_flag, fs_param_neg_with_no },
	[Opt_sloppy]		= { fs_param_is_flag },
	[Opt_soft]		= { fs_param_is_flag },
	[Opt_source]		= { fs_param_is_string },
	[Opt_tcp]		= { fs_param_is_flag },
	[Opt_timeo]		= { fs_param_is_u32 },
	[Opt_udp]		= { fs_param_is_flag },
	[Opt_v]			= { fs_param_is_flag },
	[Opt_vers]		= { fs_param_is_string },
	[Opt_wsize]		= { fs_param_is_u32 },
};

static const char *const nfs_param_keys[nr__nfs_params] = {
	[Opt_ac]		= "ac",
	[Opt_acdirmax]		= "acdirmax",
	[Opt_acdirmin]		= "acdirmin",
	[Opt_acl]		= "acl",
	[Opt_acregmax]		= "acregmax",
	[Opt_acregmin]		= "acregmin",
	[Opt_actimeo]		= "actimeo",
	[Opt_addr]		= "addr",
	[Opt_bg]		= "bg",
	[Opt_bsize]		= "bsize",
	[Opt_clientaddr]	= "clientaddr",
	[Opt_cto]		= "cto",
	[Opt_fg]		= "fg",
	[Opt_fscache]		= "fsc",
	[Opt_hard]		= "hard",
	[Opt_intr]		= "intr",
	[Opt_local_lock]	= "local_lock",
	[Opt_lock]		= "lock",
	[Opt_lookupcache]	= "lookupcache",
	[Opt_migration]		= "migration",
	[Opt_minorversion]	= "minorversion",
	[Opt_mountaddr]		= "mountaddr",
	[Opt_mounthost]		= "mounthost",
	[Opt_mountport]		= "mountport",
	[Opt_mountproto]	= "mountproto",
	[Opt_mountvers]		= "mountvers",
	[Opt_namelen]		= "namlen",
	[Opt_vers]		= "nfsvers",
	[Opt_port]		= "port",
	[Opt_posix]		= "posix",
	[Opt_proto]		= "proto",
	[Opt_rdirplus]		= "rdirplus",
	[Opt_rdma]		= "rdma",
	[Opt_resvport]		= "resvport",
	[Opt_retrans]		= "retrans",
	[Opt_retry]		= "retry",
	[Opt_rsize]		= "rsize",
	[Opt_sec]		= "sec",
	[Opt_sharecache]	= "sharecache",
	[Opt_sloppy]		= "sloppy",
	[Opt_soft]		= "soft",
	[Opt_source]		= "source",
	[Opt_tcp]		= "tcp",
	[Opt_timeo]		= "timeo",
	[Opt_udp]		= "udp",
	[Opt_v]			= "v2",
	[Opt_vers]		= "vers",
	[Opt_wsize]		= "wsize",
};

static const struct constant_table nfs_param_alt_keys[] = {
	{ "v3",			Opt_v },
	{ "v4",			Opt_v },
	{ "v4.0",		Opt_v },
	{ "v4.1",		Opt_v },
	{ "v4.2",		Opt_v },
};

enum {
	Opt_local_lock_all,
	Opt_local_lock_flock,
	Opt_local_lock_none,
	Opt_local_lock_posix,
};

enum {
	Opt_lookupcache_all,
	Opt_lookupcache_none,
	Opt_lookupcache_positive,
};

static const struct fs_parameter_enum nfs_param_enums[] = {
	{ Opt_local_lock,	"all",		Opt_local_lock_all },
	{ Opt_local_lock,	"flock",	Opt_local_lock_flock },
	{ Opt_local_lock,	"none",		Opt_local_lock_none },
	{ Opt_local_lock,	"posix",	Opt_local_lock_posix },
	{ Opt_lookupcache,	"all",		Opt_lookupcache_all },
	{ Opt_lookupcache,	"none",		Opt_lookupcache_none },
	{ Opt_lookupcache,	"pos",		Opt_lookupcache_positive },
	{ Opt_lookupcache,	"positive",	Opt_lookupcache_positive },
};

static const struct fs_parameter_description nfs_fs_parameters = {
	.name		= "nfs",
	.nr_params	= nr__nfs_params,
	.nr_alt_keys	= ARRAY_SIZE(nfs_param_alt_keys),
	.nr_enums	= ARRAY_SIZE(nfs_param_enums),
	.source_param	= Opt_source,
	.keys		= nfs_param_keys,
	.alt_keys	= nfs_param_alt_keys,
	.specs		= nfs_param_specs,
	.enums		= nfs_param_enums,
};

enum {
	Opt_vers_2,
	Opt_vers_3,
	Opt_vers_4,
	Opt_vers_4_0,
	Opt_vers_4_1,
	Opt_vers_4_2,
};

static const struct constant_table nfs_vers_tokens[] = {
	{ "2",		Opt_vers_2 },
	{ "3",		Opt_vers_3 },
	{ "4",		Opt_vers_4 },
	{ "4.0",	Opt_vers_4_0 },
	{ "4.1",	Opt_vers_4_1 },
	{ "4.2",	Opt_vers_4_2 },
};

enum {
	Opt_xprt_rdma,
	Opt_xprt_rdma6,
	Opt_xprt_tcp,
	Opt_xprt_tcp6,
	Opt_xprt_udp,
	Opt_xprt_udp6,
	nr__Opt_xprt
};

static const struct constant_table nfs_xprt_protocol_tokens[nr__Opt_xprt] = {
	{ "rdma",	Opt_xprt_rdma },
	{ "rdma6",	Opt_xprt_rdma6 },
	{ "tcp",	Opt_xprt_tcp },
	{ "tcp6",	Opt_xprt_tcp6 },
	{ "udp",	Opt_xprt_udp },
	{ "udp6",	Opt_xprt_udp },
};

enum {
	Opt_sec_krb5,
	Opt_sec_krb5i,
	Opt_sec_krb5p,
	Opt_sec_lkey,
	Opt_sec_lkeyi,
	Opt_sec_lkeyp,
	Opt_sec_none,
	Opt_sec_spkm,
	Opt_sec_spkmi,
	Opt_sec_spkmp,
	Opt_sec_sys,
	nr__Opt_sec
};

static const struct constant_table nfs_secflavor_tokens[] = {
	{ "krb5",	Opt_sec_krb5 },
	{ "krb5i",	Opt_sec_krb5i },
	{ "krb5p",	Opt_sec_krb5p },
	{ "lkey",	Opt_sec_lkey },
	{ "lkeyi",	Opt_sec_lkeyi },
	{ "lkeyp",	Opt_sec_lkeyp },
	{ "none",	Opt_sec_none },
	{ "null",	Opt_sec_none },
	{ "spkm3",	Opt_sec_spkm },
	{ "spkm3i",	Opt_sec_spkmi },
	{ "spkm3p",	Opt_sec_spkmp },
	{ "sys",	Opt_sec_sys },
};

const char nfs_slash[] = "/";
EXPORT_SYMBOL_GPL(nfs_slash);

/*
 * Sanity-check a server address provided by the mount command.
 *
 * Address family must be initialized, and address must not be
 * the ANY address for that family.
 */
static int nfs_verify_server_address(struct sockaddr *addr)
{
	switch (addr->sa_family) {
	case AF_INET: {
		struct sockaddr_in *sa = (struct sockaddr_in *)addr;
		return sa->sin_addr.s_addr != htonl(INADDR_ANY);
	}
	case AF_INET6: {
		struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
		return !ipv6_addr_any(sa);
	}
	}

	dfprintk(MOUNT, "NFS: Invalid IP address specified\n");
	return 0;
}

/*
 * Sanity check the NFS transport protocol.
 *
 */
static void nfs_validate_transport_protocol(struct nfs_fs_context *ctx)
{
	switch (ctx->nfs_server.protocol) {
	case XPRT_TRANSPORT_UDP:
	case XPRT_TRANSPORT_TCP:
	case XPRT_TRANSPORT_RDMA:
		break;
	default:
		ctx->nfs_server.protocol = XPRT_TRANSPORT_TCP;
	}
}

/*
 * For text based NFSv2/v3 mounts, the mount protocol transport default
 * settings should depend upon the specified NFS transport.
 */
static void nfs_set_mount_transport_protocol(struct nfs_fs_context *ctx)
{
	nfs_validate_transport_protocol(ctx);

	if (ctx->mount_server.protocol == XPRT_TRANSPORT_UDP ||
	    ctx->mount_server.protocol == XPRT_TRANSPORT_TCP)
			return;
	switch (ctx->nfs_server.protocol) {
	case XPRT_TRANSPORT_UDP:
		ctx->mount_server.protocol = XPRT_TRANSPORT_UDP;
		break;
	case XPRT_TRANSPORT_TCP:
	case XPRT_TRANSPORT_RDMA:
		ctx->mount_server.protocol = XPRT_TRANSPORT_TCP;
	}
}

/*
 * Add 'flavor' to 'auth_info' if not already present.
 * Returns true if 'flavor' ends up in the list, false otherwise
 */
static int nfs_auth_info_add(struct fs_context *fc,
			     struct nfs_auth_info *auth_info,
			     rpc_authflavor_t flavor)
{
	unsigned int i;
	unsigned int max_flavor_len = ARRAY_SIZE(auth_info->flavors);

	/* make sure this flavor isn't already in the list */
	for (i = 0; i < auth_info->flavor_len; i++) {
		if (flavor == auth_info->flavors[i])
			return 0;
	}

	if (auth_info->flavor_len + 1 >= max_flavor_len)
		return nfs_invalf(fc, "NFS: too many sec= flavors");

	auth_info->flavors[auth_info->flavor_len++] = flavor;
	return 0;
}

/*
 * Parse the value of the 'sec=' option.
 */
static int nfs_parse_security_flavors(struct fs_context *fc,
				      struct fs_parameter *param)
{
	struct nfs_fs_context *ctx = nfs_fc2context(fc);
	rpc_authflavor_t pseudoflavor;
	char *string = param->string, *p;
	int ret;

	dfprintk(MOUNT, "NFS: parsing %s=%s option\n", param->key, param->string);

	while ((p = strsep(&string, ":")) != NULL) {
		if (!*p)
			continue;
		switch (lookup_constant(nfs_secflavor_tokens, p, -1)) {
		case Opt_sec_none:
			pseudoflavor = RPC_AUTH_NULL;
			break;
		case Opt_sec_sys:
			pseudoflavor = RPC_AUTH_UNIX;
			break;
		case Opt_sec_krb5:
			pseudoflavor = RPC_AUTH_GSS_KRB5;
			break;
		case Opt_sec_krb5i:
			pseudoflavor = RPC_AUTH_GSS_KRB5I;
			break;
		case Opt_sec_krb5p:
			pseudoflavor = RPC_AUTH_GSS_KRB5P;
			break;
		case Opt_sec_lkey:
			pseudoflavor = RPC_AUTH_GSS_LKEY;
			break;
		case Opt_sec_lkeyi:
			pseudoflavor = RPC_AUTH_GSS_LKEYI;
			break;
		case Opt_sec_lkeyp:
			pseudoflavor = RPC_AUTH_GSS_LKEYP;
			break;
		case Opt_sec_spkm:
			pseudoflavor = RPC_AUTH_GSS_SPKM;
			break;
		case Opt_sec_spkmi:
			pseudoflavor = RPC_AUTH_GSS_SPKMI;
			break;
		case Opt_sec_spkmp:
			pseudoflavor = RPC_AUTH_GSS_SPKMP;
			break;
		default:
			return nfs_invalf(fc, "NFS: sec=%s option not recognized", p);
		}

		ret = nfs_auth_info_add(fc, &ctx->auth_info, pseudoflavor);
		if (ret < 0)
			return ret;
	}

	return 0;
}

static int nfs_parse_version_string(struct fs_context *fc,
				    const char *string)
{
	struct nfs_fs_context *ctx = nfs_fc2context(fc);

	ctx->flags &= ~NFS_MOUNT_VER3;
	switch (lookup_constant(nfs_vers_tokens, string, -1)) {
	case Opt_vers_2:
		ctx->version = 2;
		break;
	case Opt_vers_3:
		ctx->flags |= NFS_MOUNT_VER3;
		ctx->version = 3;
		break;
	case Opt_vers_4:
		/* Backward compatibility option. In future,
		 * the mount program should always supply
		 * a NFSv4 minor version number.
		 */
		ctx->version = 4;
		break;
	case Opt_vers_4_0:
		ctx->version = 4;
		ctx->minorversion = 0;
		break;
	case Opt_vers_4_1:
		ctx->version = 4;
		ctx->minorversion = 1;
		break;
	case Opt_vers_4_2:
		ctx->version = 4;
		ctx->minorversion = 2;
		break;
	default:
		return nfs_invalf(fc, "NFS: Unsupported NFS version");
	}
	return 0;
}

/*
 * Parse a single mount parameter.
 */
static int nfs_fs_context_parse_param(struct fs_context *fc,
				      struct fs_parameter *param)
{
	struct fs_parse_result result;
	struct nfs_fs_context *ctx = nfs_fc2context(fc);
	unsigned short protofamily, mountfamily;
	unsigned int len;
	int ret, opt;

	dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", param->key);

	opt = fs_parse(fc, &nfs_fs_parameters, param, &result);
	if (opt < 0)
		return fc->sloppy ? 1 : opt;

	switch (opt) {
	case Opt_source:
		if (fc->source)
			return nfs_invalf(fc, "NFS: Multiple sources not supported");
		fc->source = param->string;
		param->string = NULL;
		break;

		/*
		 * boolean options:  foo/nofoo
		 */
	case Opt_soft:
		ctx->flags |= NFS_MOUNT_SOFT;
		break;
	case Opt_hard:
		ctx->flags &= ~NFS_MOUNT_SOFT;
		break;
	case Opt_posix:
		if (result.negated)
			ctx->flags &= ~NFS_MOUNT_POSIX;
		else
			ctx->flags |= NFS_MOUNT_POSIX;
		break;
	case Opt_cto:
		if (result.negated)
			ctx->flags |= NFS_MOUNT_NOCTO;
		else
			ctx->flags &= ~NFS_MOUNT_NOCTO;
		break;
	case Opt_ac:
		if (result.negated)
			ctx->flags |= NFS_MOUNT_NOAC;
		else
			ctx->flags &= ~NFS_MOUNT_NOAC;
		break;
	case Opt_lock:
		if (result.negated) {
			ctx->flags |= NFS_MOUNT_NONLM;
			ctx->flags |= (NFS_MOUNT_LOCAL_FLOCK | NFS_MOUNT_LOCAL_FCNTL);
		} else {
			ctx->flags &= ~NFS_MOUNT_NONLM;
			ctx->flags &= ~(NFS_MOUNT_LOCAL_FLOCK | NFS_MOUNT_LOCAL_FCNTL);
		}
		break;
	case Opt_udp:
		ctx->flags &= ~NFS_MOUNT_TCP;
		ctx->nfs_server.protocol = XPRT_TRANSPORT_UDP;
		break;
	case Opt_tcp:
		ctx->flags |= NFS_MOUNT_TCP;
		ctx->nfs_server.protocol = XPRT_TRANSPORT_TCP;
		break;
	case Opt_rdma:
		ctx->flags |= NFS_MOUNT_TCP; /* for side protocols */
		ctx->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
		xprt_load_transport(param->key);
		break;
	case Opt_acl:
		if (result.negated)
			ctx->flags |= NFS_MOUNT_NOACL;
		else
			ctx->flags &= ~NFS_MOUNT_NOACL;
		break;
	case Opt_rdirplus:
		if (result.negated)
			ctx->flags |= NFS_MOUNT_NORDIRPLUS;
		else
			ctx->flags &= ~NFS_MOUNT_NORDIRPLUS;
		break;
	case Opt_sharecache:
		if (result.negated)
			ctx->flags |= NFS_MOUNT_UNSHARED;
		else
			ctx->flags &= ~NFS_MOUNT_UNSHARED;
		break;
	case Opt_resvport:
		if (result.negated)
			ctx->flags |= NFS_MOUNT_NORESVPORT;
		else
			ctx->flags &= ~NFS_MOUNT_NORESVPORT;
		break;
	case Opt_fscache:
		kfree(ctx->fscache_uniq);
		ctx->fscache_uniq = NULL;
		if (result.negated) {
			ctx->options &= ~NFS_OPTION_FSCACHE;
		} else if (result.has_value) {
			ctx->options |= NFS_OPTION_FSCACHE;
			ctx->fscache_uniq = param->string;
			param->string = NULL;
		} else {
			ctx->options |= NFS_OPTION_FSCACHE;
		}
		break;
	case Opt_migration:
		if (result.negated)
			ctx->options &= ~NFS_OPTION_MIGRATION;
		else
			ctx->options |= NFS_OPTION_MIGRATION;
		break;

		/*
		 * options that take numeric values
		 */
	case Opt_port:
		if (result.uint_32 > USHRT_MAX)
			goto out_of_bounds;
		ctx->nfs_server.port = result.uint_32;
		break;
	case Opt_rsize:
		ctx->rsize = result.uint_32;
		break;
	case Opt_wsize:
		ctx->wsize = result.uint_32;
		break;
	case Opt_bsize:
		ctx->bsize = result.uint_32;
		break;
	case Opt_timeo:
		if (result.uint_32 < 1 || result.uint_32 > INT_MAX)
			goto out_of_bounds;
		ctx->timeo = result.uint_32;
		break;
	case Opt_retrans:
		if (result.uint_32 > INT_MAX)
			goto out_of_bounds;
		ctx->retrans = result.uint_32;
		break;
	case Opt_acregmin:
		ctx->acregmin = result.uint_32;
		break;
	case Opt_acregmax:
		ctx->acregmax = result.uint_32;
		break;
	case Opt_acdirmin:
		ctx->acdirmin = result.uint_32;
		break;
	case Opt_acdirmax:
		ctx->acdirmax = result.uint_32;
		break;
	case Opt_actimeo:
		ctx->acregmin = result.uint_32;
		ctx->acregmax = result.uint_32;
		ctx->acdirmin = result.uint_32;
		ctx->acdirmax = result.uint_32;
		break;
	case Opt_namelen:
		ctx->namlen = result.uint_32;
		break;
	case Opt_mountport:
		if (result.uint_32 > USHRT_MAX)
			goto out_of_bounds;
		ctx->mount_server.port = result.uint_32;
		break;
	case Opt_mountvers:
		if (result.uint_32 < NFS_MNT_VERSION ||
		    result.uint_32 > NFS_MNT3_VERSION)
			goto out_of_bounds;
		ctx->mount_server.version = result.uint_32;
		break;
	case Opt_minorversion:
		if (result.uint_32 > NFS4_MAX_MINOR_VERSION)
			goto out_of_bounds;
		ctx->minorversion = result.uint_32;
		break;

		/*
		 * options that take text values
		 */
	case Opt_v:
		ret = nfs_parse_version_string(fc, param->key + 1);
		if (ret < 0)
			return ret;
		break;
	case Opt_vers:
		ret = nfs_parse_version_string(fc, param->string);
		if (ret < 0)
			return ret;
		break;
	case Opt_sec:
		ret = nfs_parse_security_flavors(fc, param);
		if (ret < 0)
			return ret;
		break;

	case Opt_proto:
		protofamily = AF_INET;
		switch (lookup_constant(nfs_xprt_protocol_tokens, param->string, -1)) {
		case Opt_xprt_udp6:
			protofamily = AF_INET6;
			/* fall through */
		case Opt_xprt_udp:
			ctx->flags &= ~NFS_MOUNT_TCP;
			ctx->nfs_server.protocol = XPRT_TRANSPORT_UDP;
			break;
		case Opt_xprt_tcp6:
			protofamily = AF_INET6;
			/* fall through */
		case Opt_xprt_tcp:
			ctx->flags |= NFS_MOUNT_TCP;
			ctx->nfs_server.protocol = XPRT_TRANSPORT_TCP;
			break;
		case Opt_xprt_rdma6:
			protofamily = AF_INET6;
			/* fall through */
		case Opt_xprt_rdma:
			/* vector side protocols to TCP */
			ctx->flags |= NFS_MOUNT_TCP;
			ctx->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
			xprt_load_transport(param->string);
			break;
		default:
			return nfs_invalf(fc, "NFS: Unrecognized transport protocol");
		}

		ctx->protofamily = protofamily;
		break;

	case Opt_mountproto:
		mountfamily = AF_INET;
		switch (lookup_constant(nfs_xprt_protocol_tokens, param->string, -1)) {
		case Opt_xprt_udp6:
			mountfamily = AF_INET6;
			/* fall through */
		case Opt_xprt_udp:
			ctx->mount_server.protocol = XPRT_TRANSPORT_UDP;
			break;
		case Opt_xprt_tcp6:
			mountfamily = AF_INET6;
			/* fall through */
		case Opt_xprt_tcp:
			ctx->mount_server.protocol = XPRT_TRANSPORT_TCP;
			break;
		case Opt_xprt_rdma: /* not used for side protocols */
		default:
			return nfs_invalf(fc, "NFS: Unrecognized transport protocol");
		}
		ctx->mountfamily = mountfamily;
		break;

	case Opt_addr:
		len = rpc_pton(fc->net_ns, param->string, param->size,
			       &ctx->nfs_server.address,
			       sizeof(ctx->nfs_server._address));
		if (len == 0)
			goto out_invalid_address;
		ctx->nfs_server.addrlen = len;
		break;
	case Opt_clientaddr:
		kfree(ctx->client_address);
		ctx->client_address = param->string;
		param->string = NULL;
		break;
	case Opt_mounthost:
		kfree(ctx->mount_server.hostname);
		ctx->mount_server.hostname = param->string;
		param->string = NULL;
		break;
	case Opt_mountaddr:
		len = rpc_pton(fc->net_ns, param->string, param->size,
			       &ctx->mount_server.address,
			       sizeof(ctx->mount_server._address));
		if (len == 0)
			goto out_invalid_address;
		ctx->mount_server.addrlen = len;
		break;
	case Opt_lookupcache:
		switch (result.uint_32) {
		case Opt_lookupcache_all:
			ctx->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
			break;
		case Opt_lookupcache_positive:
			ctx->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
			ctx->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
			break;
		case Opt_lookupcache_none:
			ctx->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
			break;
		default:
			goto out_invalid_value;
		}
		break;
	case Opt_local_lock:
		switch (result.uint_32) {
		case Opt_local_lock_all:
			ctx->flags |= (NFS_MOUNT_LOCAL_FLOCK |
				       NFS_MOUNT_LOCAL_FCNTL);
			break;
		case Opt_local_lock_flock:
			ctx->flags |= NFS_MOUNT_LOCAL_FLOCK;
			break;
		case Opt_local_lock_posix:
			ctx->flags |= NFS_MOUNT_LOCAL_FCNTL;
			break;
		case Opt_local_lock_none:
			ctx->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
					NFS_MOUNT_LOCAL_FCNTL);
			break;
		default:
			goto out_invalid_value;
		}
		break;

		/*
		 * Special options
		 */
	case Opt_sloppy:
		fc->sloppy = true;
		dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
		break;
	}

	return 0;

out_invalid_value:
	return nfs_invalf(fc, "NFS: Bad mount option value specified");
out_invalid_address:
	return nfs_invalf(fc, "NFS: Bad IP address specified");
out_of_bounds:
	nfs_invalf(fc, "NFS: Value for '%s' out of range", param->key);
	return -ERANGE;
}

/*
 * Split fc->source into "hostname:export_path".
 *
 * The leftmost colon demarks the split between the server's hostname
 * and the export path.  If the hostname starts with a left square
 * bracket, then it may contain colons.
 *
 * Note: caller frees hostname and export path, even on error.
 */
static int nfs_parse_source(struct fs_context *fc,
			    size_t maxnamlen, size_t maxpathlen)
{
	struct nfs_fs_context *ctx = nfs_fc2context(fc);
	const char *dev_name = fc->source;
	size_t len;
	const char *end;

	/* Is the host name protected with square brakcets? */
	if (*dev_name == '[') {
		end = strchr(++dev_name, ']');
		if (end == NULL || end[1] != ':')
			goto out_bad_devname;

		len = end - dev_name;
		end++;
	} else {
		const char *comma;

		end = strchr(dev_name, ':');
		if (end == NULL)
			goto out_bad_devname;
		len = end - dev_name;

		/* kill possible hostname list: not supported */
		comma = memchr(dev_name, ',', len);
		if (comma)
			len = comma - dev_name;
	}

	if (len > maxnamlen)
		goto out_hostname;

	/* N.B. caller will free nfs_server.hostname in all cases */
	ctx->nfs_server.hostname = kmemdup_nul(dev_name, len, GFP_KERNEL);
	if (!ctx->nfs_server.hostname)
		goto out_nomem;
	len = strlen(++end);
	if (len > maxpathlen)
		goto out_path;
	ctx->nfs_server.export_path = kmemdup_nul(end, len, GFP_KERNEL);
	if (!ctx->nfs_server.export_path)
		goto out_nomem;

	dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", ctx->nfs_server.export_path);
	return 0;

out_bad_devname:
	return nfs_invalf(fc, "NFS: device name not in host:path format");
out_nomem:
	nfs_errorf(fc, "NFS: not enough memory to parse device name");
	return -ENOMEM;
out_hostname:
	nfs_errorf(fc, "NFS: server hostname too long");
	return -ENAMETOOLONG;
out_path:
	nfs_errorf(fc, "NFS: export pathname too long");
	return -ENAMETOOLONG;
}

/*
 * Parse monolithic NFS2/NFS3 mount data
 * - fills in the mount root filehandle
 *
 * For option strings, user space handles the following behaviors:
 *
 * + DNS: mapping server host name to IP address ("addr=" option)
 *
 * + failure mode: how to behave if a mount request can't be handled
 *   immediately ("fg/bg" option)
 *
 * + retry: how often to retry a mount request ("retry=" option)
 *
 * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
 *   mountproto=tcp after mountproto=udp, and so on
 */
static int nfs23_parse_monolithic(struct fs_context *fc,
				  struct nfs_mount_data *data)
{
	struct nfs_fs_context *ctx = nfs_fc2context(fc);
	struct nfs_fh *mntfh = ctx->mntfh;
	struct sockaddr *sap = (struct sockaddr *)&ctx->nfs_server.address;
	int extra_flags = NFS_MOUNT_LEGACY_INTERFACE;

	if (data == NULL)
		goto out_no_data;

	ctx->version = NFS_DEFAULT_VERSION;
	switch (data->version) {
	case 1:
		data->namlen = 0; /* fall through */
	case 2:
		data->bsize = 0; /* fall through */
	case 3:
		if (data->flags & NFS_MOUNT_VER3)
			goto out_no_v3;
		data->root.size = NFS2_FHSIZE;
		memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
		/* Turn off security negotiation */
		extra_flags |= NFS_MOUNT_SECFLAVOUR;
		/* fall through */
	case 4:
		if (data->flags & NFS_MOUNT_SECFLAVOUR)
			goto out_no_sec;
		/* fall through */
	case 5:
		memset(data->context, 0, sizeof(data->context));
		/* fall through */
	case 6:
		if (data->flags & NFS_MOUNT_VER3) {
			if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
				goto out_invalid_fh;
			mntfh->size = data->root.size;
			ctx->version = 3;
		} else {
			mntfh->size = NFS2_FHSIZE;
			ctx->version = 2;
		}


		memcpy(mntfh->data, data->root.data, mntfh->size);
		if (mntfh->size < sizeof(mntfh->data))
			memset(mntfh->data + mntfh->size, 0,
			       sizeof(mntfh->data) - mntfh->size);

		/*
		 * Translate to nfs_fs_context, which nfs_fill_super
		 * can deal with.
		 */
		ctx->flags	= data->flags & NFS_MOUNT_FLAGMASK;
		ctx->flags	|= extra_flags;
		ctx->rsize	= data->rsize;
		ctx->wsize	= data->wsize;
		ctx->timeo	= data->timeo;
		ctx->retrans	= data->retrans;
		ctx->acregmin	= data->acregmin;
		ctx->acregmax	= data->acregmax;
		ctx->acdirmin	= data->acdirmin;
		ctx->acdirmax	= data->acdirmax;
		ctx->need_mount	= false;

		memcpy(sap, &data->addr, sizeof(data->addr));
		ctx->nfs_server.addrlen = sizeof(data->addr);
		ctx->nfs_server.port = ntohs(data->addr.sin_port);
		if (!nfs_verify_server_address(sap))
			goto out_no_address;

		if (!(data->flags & NFS_MOUNT_TCP))
			ctx->nfs_server.protocol = XPRT_TRANSPORT_UDP;
		/* N.B. caller will free nfs_server.hostname in all cases */
		ctx->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
		if (!ctx->nfs_server.hostname)
			goto out_nomem;

		ctx->namlen		= data->namlen;
		ctx->bsize		= data->bsize;

		if (data->flags & NFS_MOUNT_SECFLAVOUR)
			ctx->selected_flavor = data->pseudoflavor;
		else
			ctx->selected_flavor = RPC_AUTH_UNIX;

		if (!(data->flags & NFS_MOUNT_NONLM))
			ctx->flags &= ~(NFS_MOUNT_LOCAL_FLOCK|
					 NFS_MOUNT_LOCAL_FCNTL);
		else
			ctx->flags |= (NFS_MOUNT_LOCAL_FLOCK|
					NFS_MOUNT_LOCAL_FCNTL);

		/*
		 * The legacy version 6 binary mount data from userspace has a
		 * field used only to transport selinux information into the
		 * the kernel.  To continue to support that functionality we
		 * have a touch of selinux knowledge here in the NFS code. The
		 * userspace code converted context=blah to just blah so we are
		 * converting back to the full string selinux understands.
		 */
		if (data->context[0]){
#ifdef CONFIG_SECURITY_SELINUX
			int ret;

			data->context[NFS_MAX_CONTEXT_LEN] = '\0';
			ret = vfs_parse_fs_string(fc, "context",
						  data->context, strlen(data->context));
			if (ret < 0)
				return ret;
#else
			return -EINVAL;
#endif
		}

		break;
	default:
		goto generic;
	}

	ctx->skip_reconfig_option_check = true;
	return 0;

generic:
	return generic_parse_monolithic(fc, data);

out_no_data:
	if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
		ctx->skip_reconfig_option_check = true;
		return 0;
	}
	return nfs_invalf(fc, "NFS: mount program didn't pass any mount data");

out_no_v3:
	return nfs_invalf(fc, "NFS: nfs_mount_data version does not support v3");

out_no_sec:
	return nfs_invalf(fc, "NFS: nfs_mount_data version supports only AUTH_SYS");

out_nomem:
	dfprintk(MOUNT, "NFS: not enough memory to handle mount options");
	return -ENOMEM;

out_no_address:
	return nfs_invalf(fc, "NFS: mount program didn't pass remote address");

out_invalid_fh:
	return nfs_invalf(fc, "NFS: invalid root filehandle");
}

/*
 * Validate NFSv4 mount options
 */
static int nfs4_parse_monolithic(struct fs_context *fc,
				 struct nfs4_mount_data *data)
{
	struct nfs_fs_context *ctx = nfs_fc2context(fc);
	struct sockaddr *sap = (struct sockaddr *)&ctx->nfs_server.address;
	char *c;

	if (data == NULL)
		goto out_no_data;

	ctx->version = 4;

	switch (data->version) {
	case 1:
		if (data->host_addrlen > sizeof(ctx->nfs_server.address))
			goto out_no_address;
		if (data->host_addrlen == 0)
			goto out_no_address;
		ctx->nfs_server.addrlen = data->host_addrlen;
		if (copy_from_user(sap, data->host_addr, data->host_addrlen))
			return -EFAULT;
		if (!nfs_verify_server_address(sap))
			goto out_no_address;
		ctx->nfs_server.port = ntohs(((struct sockaddr_in *)sap)->sin_port);

		if (data->auth_flavourlen) {
			rpc_authflavor_t pseudoflavor;
			if (data->auth_flavourlen > 1)
				goto out_inval_auth;
			if (copy_from_user(&pseudoflavor,
					   data->auth_flavours,
					   sizeof(pseudoflavor)))
				return -EFAULT;
			ctx->selected_flavor = pseudoflavor;
		} else
			ctx->selected_flavor = RPC_AUTH_UNIX;

		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
		if (IS_ERR(c))
			return PTR_ERR(c);
		ctx->nfs_server.hostname = c;

		c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
		if (IS_ERR(c))
			return PTR_ERR(c);
		ctx->nfs_server.export_path = c;
		dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);

		c = strndup_user(data->client_addr.data, 16);
		if (IS_ERR(c))
			return PTR_ERR(c);
		ctx->client_address = c;

		/*
		 * Translate to nfs_fs_context, which nfs_fill_super
		 * can deal with.
		 */

		ctx->flags	= data->flags & NFS4_MOUNT_FLAGMASK;
		ctx->rsize	= data->rsize;
		ctx->wsize	= data->wsize;
		ctx->timeo	= data->timeo;
		ctx->retrans	= data->retrans;
		ctx->acregmin	= data->acregmin;
		ctx->acregmax	= data->acregmax;
		ctx->acdirmin	= data->acdirmin;
		ctx->acdirmax	= data->acdirmax;
		ctx->nfs_server.protocol = data->proto;
		nfs_validate_transport_protocol(ctx);
		if (ctx->nfs_server.protocol == XPRT_TRANSPORT_UDP)
			goto out_invalid_transport_udp;

		break;
	default:
		goto generic;
	}

	ctx->skip_reconfig_option_check = true;
	return 0;

generic:
	return generic_parse_monolithic(fc, data);

out_no_data:
	if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
		ctx->skip_reconfig_option_check = true;
		return 0;
	}
	return nfs_invalf(fc, "NFS4: mount program didn't pass any mount data");

out_inval_auth:
	return nfs_invalf(fc, "NFS4: Invalid number of RPC auth flavours %d",
		      data->auth_flavourlen);

out_no_address:
	return nfs_invalf(fc, "NFS4: mount program didn't pass remote address");

out_invalid_transport_udp:
	return nfs_invalf(fc, "NFSv4: Unsupported transport protocol udp");
}

/*
 * Parse a monolithic block of data from sys_mount().
 */
static int nfs_fs_context_parse_monolithic(struct fs_context *fc,
					   void *data)
{
	if (fc->fs_type == &nfs_fs_type)
		return nfs23_parse_monolithic(fc, data);

#if IS_ENABLED(CONFIG_NFS_V4)
	if (fc->fs_type == &nfs4_fs_type)
		return nfs4_parse_monolithic(fc, data);
#endif

	return nfs_invalf(fc, "NFS: Unsupported monolithic data version");
}

/*
 * Validate the preparsed information in the config.
 */
static int nfs_fs_context_validate(struct fs_context *fc)
{
	struct nfs_fs_context *ctx = nfs_fc2context(fc);
	struct nfs_subversion *nfs_mod;
	struct sockaddr *sap = (struct sockaddr *)&ctx->nfs_server.address;
	int max_namelen = PAGE_SIZE;
	int max_pathlen = NFS_MAXPATHLEN;
	int port = 0;
	int ret;

	if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE)
		return 0;

	if (!fc->source)
		goto out_no_device_name;

	/* Check for sanity first. */
	if (ctx->minorversion && ctx->version != 4)
		goto out_minorversion_mismatch;

	if (ctx->options & NFS_OPTION_MIGRATION &&
	    (ctx->version != 4 || ctx->minorversion != 0))
		goto out_migration_misuse;

	/* Verify that any proto=/mountproto= options match the address
	 * families in the addr=/mountaddr= options.
	 */
	if (ctx->protofamily != AF_UNSPEC &&
	    ctx->protofamily != ctx->nfs_server.address.sa_family)
		goto out_proto_mismatch;

	if (ctx->mountfamily != AF_UNSPEC) {
		if (ctx->mount_server.addrlen) {
			if (ctx->mountfamily != ctx->mount_server.address.sa_family)
				goto out_mountproto_mismatch;
		} else {
			if (ctx->mountfamily != ctx->nfs_server.address.sa_family)
				goto out_mountproto_mismatch;
		}
	}

	if (!nfs_verify_server_address(sap))
		goto out_no_address;

	if (ctx->version == 4) {
		if (IS_ENABLED(CONFIG_NFS_V4)) {
			port = NFS_PORT;
			max_namelen = NFS4_MAXNAMLEN;
			max_pathlen = NFS4_MAXPATHLEN;
			nfs_validate_transport_protocol(ctx);
			if (ctx->nfs_server.protocol == XPRT_TRANSPORT_UDP)
				goto out_invalid_transport_udp;
			ctx->flags &= ~(NFS_MOUNT_NONLM | NFS_MOUNT_NOACL |
					NFS_MOUNT_VER3 | NFS_MOUNT_LOCAL_FLOCK |
					NFS_MOUNT_LOCAL_FCNTL);
		} else {
			goto out_v4_not_compiled;
		}
	} else {
		nfs_set_mount_transport_protocol(ctx);
	}

	nfs_set_port(sap, &ctx->nfs_server.port, port);

	ret = nfs_parse_source(fc, max_namelen, max_pathlen);
	if (ret < 0)
		return ret;

	/* Load the NFS protocol module if we haven't done so yet */
	if (!ctx->nfs_mod) {
		nfs_mod = get_nfs_version(ctx->version);
		if (IS_ERR(nfs_mod)) {
			ret = PTR_ERR(nfs_mod);
			goto out_version_unavailable;
		}
		ctx->nfs_mod = nfs_mod;
	}
	return 0;

out_no_device_name:
	return nfs_invalf(fc, "NFS: Device name not specified");
out_v4_not_compiled:
	nfs_errorf(fc, "NFS: NFSv4 is not compiled into kernel");
	return -EPROTONOSUPPORT;
out_invalid_transport_udp:
	return nfs_invalf(fc, "NFSv4: Unsupported transport protocol udp");
out_no_address:
	return nfs_invalf(fc, "NFS: mount program didn't pass remote address");
out_mountproto_mismatch:
	return nfs_invalf(fc, "NFS: Mount server address does not match mountproto= option");
out_proto_mismatch:
	return nfs_invalf(fc, "NFS: Server address does not match proto= option");
out_minorversion_mismatch:
	return nfs_invalf(fc, "NFS: Mount option vers=%u does not support minorversion=%u",
			  ctx->version, ctx->minorversion);
out_migration_misuse:
	return nfs_invalf(fc, "NFS: 'Migration' not supported for this NFS version");
out_version_unavailable:
	nfs_errorf(fc, "NFS: Version unavailable");
	return ret;
}

/*
 * Use the preparsed information in the config to effect a mount.
 */
static int nfs_get_ordinary_tree(struct fs_context *fc)
{
	struct nfs_fs_context *ctx = nfs_fc2context(fc);

	ctx->set_security = nfs_set_sb_security;

	return ctx->nfs_mod->rpc_ops->try_get_tree(fc);
}

/*
 * Clone an NFS2/3/4 server record on xdev traversal (FSID-change)
 */
static int nfs_get_xdev_tree(struct fs_context *fc)
{
	struct nfs_fs_context *ctx = nfs_fc2context(fc);
	struct nfs_server *server;
	int ret;

	dprintk("--> nfs_xdev_mount()\n");

	ctx->set_security = nfs_clone_sb_security;

	/* create a new volume representation */
	server = ctx->nfs_mod->rpc_ops->clone_server(NFS_SB(ctx->clone_data.sb),
						     ctx->mntfh,
						     ctx->clone_data.fattr,
						     ctx->selected_flavor);

	if (IS_ERR(server))
		ret = PTR_ERR(server);
	else
		ret = nfs_get_tree_common(server, fc);

	dprintk("<-- nfs_get_xdev_tree() = %d\n", ret);
	return ret;
}

/*
 * Create an NFS superblock by the appropriate method.
 */
static int nfs_get_tree(struct fs_context *fc)
{
	struct nfs_fs_context *ctx = nfs_fc2context(fc);
	int ret;

	if (!ctx->nfs_mod) {
		pr_warn("Missing nfs_mod\n");
		return -EINVAL;
	}
	if (!ctx->nfs_mod->rpc_ops) {
		pr_warn("Missing rpc_ops\n");
		return -EINVAL;
	}

	if (ctx->nfs_mod->rpc_ops->get_tree) {
		ret = ctx->nfs_mod->rpc_ops->get_tree(fc);
		if (ret != 1)
			return ret;
	}

	switch (ctx->mount_type) {
	case NFS_MOUNT_ORDINARY:
		return nfs_get_ordinary_tree(fc);

	case NFS_MOUNT_CROSS_DEV:
		return nfs_get_xdev_tree(fc);

	default:
		nfs_errorf(fc, "NFS: Unknown mount type");
		return -ENOTSUPP;
	}
}

/*
 * Handle duplication of a configuration.  The caller copied *src into *sc, but
 * it can't deal with resource pointers in the filesystem context, so we have
 * to do that.  We need to clear pointers, copy data or get extra refs as
 * appropriate.
 */
static int nfs_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc)
{
	struct nfs_fs_context *src = nfs_fc2context(src_fc), *ctx;

	ctx = kmemdup(src, sizeof(struct nfs_fs_context), GFP_KERNEL);
	if (!ctx)
		return -ENOMEM;

	ctx->mntfh = nfs_alloc_fhandle();
	if (!ctx->mntfh) {
		return -ENOMEM;
		kfree(ctx);
	}

	__module_get(ctx->nfs_mod->owner);
	ctx->client_address		= NULL;
	ctx->mount_server.hostname	= NULL;
	ctx->nfs_server.export_path	= NULL;
	ctx->nfs_server.hostname	= NULL;
	ctx->fscache_uniq		= NULL;
	fc->fs_private = ctx;
	return 0;
}

static void nfs_fs_context_free(struct fs_context *fc)
{
	struct nfs_fs_context *ctx = nfs_fc2context(fc);

	if (ctx) {
		if (ctx->nfs_mod)
			put_nfs_version(ctx->nfs_mod);
		kfree(ctx->client_address);
		kfree(ctx->mount_server.hostname);
		if (ctx->nfs_server.export_path != nfs_slash)
			kfree(ctx->nfs_server.export_path);
		kfree(ctx->nfs_server.hostname);
		kfree(ctx->fscache_uniq);
		nfs_free_fhandle(ctx->mntfh);
		kfree(ctx);
	}
}

static const struct fs_context_operations nfs_fs_context_ops = {
	.free			= nfs_fs_context_free,
	.dup			= nfs_fs_context_dup,
	.parse_param		= nfs_fs_context_parse_param,
	.parse_monolithic	= nfs_fs_context_parse_monolithic,
	.validate		= nfs_fs_context_validate,
	.get_tree		= nfs_get_tree,
	.reconfigure		= nfs_reconfigure,
};

/*
 * Initialise a configuration from an extant superblock for automounting and
 * reconfiguration.
 */
static int nfs_mount_init_from_ref(struct fs_context *fc,
				   struct nfs_fs_context *ctx,
				   struct dentry *reference)
{
	struct nfs_server *nfss = reference->d_sb->s_fs_info;
	struct net *net = nfss->nfs_client->cl_net;

	ctx->flags		= nfss->flags;
	ctx->rsize		= nfss->rsize;
	ctx->wsize		= nfss->wsize;
	ctx->retrans		= nfss->client->cl_timeout->to_retries;
	ctx->selected_flavor	= nfss->client->cl_auth->au_flavor;
	ctx->acregmin		= nfss->acregmin / HZ;
	ctx->acregmax		= nfss->acregmax / HZ;
	ctx->acdirmin		= nfss->acdirmin / HZ;
	ctx->acdirmax		= nfss->acdirmax / HZ;
	ctx->timeo		= 10U * nfss->client->cl_timeout->to_initval / HZ;
	ctx->nfs_server.port	= nfss->port;
	ctx->nfs_server.addrlen	= nfss->nfs_client->cl_addrlen;
	ctx->version		= nfss->nfs_client->rpc_ops->version;
	ctx->minorversion	= nfss->nfs_client->cl_minorversion;

	memcpy(&ctx->nfs_server.address, &nfss->nfs_client->cl_addr,
		ctx->nfs_server.addrlen);

	if (fc->net_ns != net) {
		put_net(fc->net_ns);
		fc->net_ns = get_net(net);
	}

	ctx->nfs_mod = nfss->nfs_client->cl_nfs_mod;
	if (!try_module_get(ctx->nfs_mod->owner)) {
		ctx->nfs_mod = NULL;
		nfs_errorf(fc, "NFS: Protocol module not available");
		return -ENOENT;
	}

	return 0;
}

/*
 * Prepare superblock configuration.  We use the namespaces attached to the
 * context.  This may be the current process's namespaces, or it may be a
 * container's namespaces.
 */
static int nfs_init_fs_context(struct fs_context *fc, struct dentry *reference)
{
	struct nfs_fs_context *ctx;
	int ret = -ENOMEM;

	ctx = kzalloc(sizeof(struct nfs_fs_context), GFP_KERNEL);
	if (!ctx)
		goto error;

	ctx->mntfh = nfs_alloc_fhandle();
	if (!ctx->mntfh)
		goto error_ctx;

	ctx->mount_type		= NFS_MOUNT_ORDINARY;
	ctx->protofamily	= AF_UNSPEC;
	ctx->mountfamily	= AF_UNSPEC;
	ctx->mount_server.port	= NFS_UNSPEC_PORT;

	switch (fc->purpose) {
	case FS_CONTEXT_FOR_ROOT_MOUNT:
	case FS_CONTEXT_FOR_USER_MOUNT:
	case FS_CONTEXT_FOR_KERNEL_MOUNT:
		ctx->timeo		= NFS_UNSPEC_TIMEO;
		ctx->retrans		= NFS_UNSPEC_RETRANS;
		ctx->acregmin		= NFS_DEF_ACREGMIN;
		ctx->acregmax		= NFS_DEF_ACREGMAX;
		ctx->acdirmin		= NFS_DEF_ACDIRMIN;
		ctx->acdirmax		= NFS_DEF_ACDIRMAX;
		ctx->nfs_server.port	= NFS_UNSPEC_PORT;
		ctx->nfs_server.protocol = XPRT_TRANSPORT_TCP;
		ctx->selected_flavor	= RPC_AUTH_MAXFLAVOR;
		ctx->minorversion	= 0;
		ctx->need_mount		= true;
		break;

	case FS_CONTEXT_FOR_SUBMOUNT:
		ret = -EINVAL;
		if (!reference)
			goto error_fh;
		/* Fall through */
	case FS_CONTEXT_FOR_RECONFIGURE:
		ret = nfs_mount_init_from_ref(fc, ctx, reference);
		if (ret < 0)
			goto error_fh;
		/* Fall through */
	case FS_CONTEXT_FOR_UMOUNT:
	case FS_CONTEXT_FOR_EMERGENCY_RO:
		break;
	}

	fc->fs_private = ctx;
	fc->ops = &nfs_fs_context_ops;
	return 0;

error_fh:
	nfs_free_fhandle(ctx->mntfh);
error_ctx:
	kfree(ctx);
error:
	return ret;
}

struct file_system_type nfs_fs_type = {
	.owner			= THIS_MODULE,
	.name			= "nfs",
	.init_fs_context	= nfs_init_fs_context,
	.parameters		= &nfs_fs_parameters,
	.kill_sb		= nfs_kill_super,
	.fs_flags		= FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
};
MODULE_ALIAS_FS("nfs");
EXPORT_SYMBOL_GPL(nfs_fs_type);

#if IS_ENABLED(CONFIG_NFS_V4)
struct file_system_type nfs4_fs_type = {
	.owner			= THIS_MODULE,
	.name			= "nfs4",
	.init_fs_context	= nfs_init_fs_context,
	.parameters		= &nfs_fs_parameters,
	.kill_sb		= nfs_kill_super,
	.fs_flags		= FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
};
MODULE_ALIAS_FS("nfs4");
MODULE_ALIAS("nfs4");
EXPORT_SYMBOL_GPL(nfs4_fs_type);
#endif /* CONFIG_NFS_V4 */