1 files changed, 1603 insertions, 0 deletions

diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c
new file mode 100644
index 000000000..9bcd53d5c
--- /dev/null
+++ b/fs/nfs/fs_context.c
@@ -0,0 +1,1603 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/nfs/fs_context.c
+ *
+ * Copyright (C) 1992 Rick Sladkey
+ * Conversion to new mount api Copyright (C) David Howells
+ *
+ * NFS mount handling.
+ *
+ * Split from fs/nfs/super.c by David Howells <dhowells@redhat.com>
+ */
+
+#include <linux/compat.h>
+#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"
+
+#include "nfstrace.h"
+
+#define NFSDBG_FACILITY		NFSDBG_MOUNT
+
+#if IS_ENABLED(CONFIG_NFS_V3)
+#define NFS_DEFAULT_VERSION 3
+#else
+#define NFS_DEFAULT_VERSION 2
+#endif
+
+#define NFS_MAX_CONNECTIONS 16
+
+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_fscache_flag,
+	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_nconnect,
+	Opt_max_connect,
+	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_softerr,
+	Opt_softreval,
+	Opt_source,
+	Opt_tcp,
+	Opt_timeo,
+	Opt_trunkdiscovery,
+	Opt_udp,
+	Opt_v,
+	Opt_vers,
+	Opt_wsize,
+	Opt_write,
+};
+
+enum {
+	Opt_local_lock_all,
+	Opt_local_lock_flock,
+	Opt_local_lock_none,
+	Opt_local_lock_posix,
+};
+
+static const struct constant_table nfs_param_enums_local_lock[] = {
+	{ "all",		Opt_local_lock_all },
+	{ "flock",	Opt_local_lock_flock },
+	{ "posix",	Opt_local_lock_posix },
+	{ "none",		Opt_local_lock_none },
+	{}
+};
+
+enum {
+	Opt_lookupcache_all,
+	Opt_lookupcache_none,
+	Opt_lookupcache_positive,
+};
+
+static const struct constant_table nfs_param_enums_lookupcache[] = {
+	{ "all",		Opt_lookupcache_all },
+	{ "none",		Opt_lookupcache_none },
+	{ "pos",		Opt_lookupcache_positive },
+	{ "positive",		Opt_lookupcache_positive },
+	{}
+};
+
+enum {
+	Opt_write_lazy,
+	Opt_write_eager,
+	Opt_write_wait,
+};
+
+static const struct constant_table nfs_param_enums_write[] = {
+	{ "lazy",		Opt_write_lazy },
+	{ "eager",		Opt_write_eager },
+	{ "wait",		Opt_write_wait },
+	{}
+};
+
+static const struct fs_parameter_spec nfs_fs_parameters[] = {
+	fsparam_flag_no("ac",		Opt_ac),
+	fsparam_u32   ("acdirmax",	Opt_acdirmax),
+	fsparam_u32   ("acdirmin",	Opt_acdirmin),
+	fsparam_flag_no("acl",		Opt_acl),
+	fsparam_u32   ("acregmax",	Opt_acregmax),
+	fsparam_u32   ("acregmin",	Opt_acregmin),
+	fsparam_u32   ("actimeo",	Opt_actimeo),
+	fsparam_string("addr",		Opt_addr),
+	fsparam_flag  ("bg",		Opt_bg),
+	fsparam_u32   ("bsize",		Opt_bsize),
+	fsparam_string("clientaddr",	Opt_clientaddr),
+	fsparam_flag_no("cto",		Opt_cto),
+	fsparam_flag  ("fg",		Opt_fg),
+	fsparam_flag_no("fsc",		Opt_fscache_flag),
+	fsparam_string("fsc",		Opt_fscache),
+	fsparam_flag  ("hard",		Opt_hard),
+	__fsparam(NULL, "intr",		Opt_intr,
+		  fs_param_neg_with_no|fs_param_deprecated, NULL),
+	fsparam_enum  ("local_lock",	Opt_local_lock, nfs_param_enums_local_lock),
+	fsparam_flag_no("lock",		Opt_lock),
+	fsparam_enum  ("lookupcache",	Opt_lookupcache, nfs_param_enums_lookupcache),
+	fsparam_flag_no("migration",	Opt_migration),
+	fsparam_u32   ("minorversion",	Opt_minorversion),
+	fsparam_string("mountaddr",	Opt_mountaddr),
+	fsparam_string("mounthost",	Opt_mounthost),
+	fsparam_u32   ("mountport",	Opt_mountport),
+	fsparam_string("mountproto",	Opt_mountproto),
+	fsparam_u32   ("mountvers",	Opt_mountvers),
+	fsparam_u32   ("namlen",	Opt_namelen),
+	fsparam_u32   ("nconnect",	Opt_nconnect),
+	fsparam_u32   ("max_connect",	Opt_max_connect),
+	fsparam_string("nfsvers",	Opt_vers),
+	fsparam_u32   ("port",		Opt_port),
+	fsparam_flag_no("posix",	Opt_posix),
+	fsparam_string("proto",		Opt_proto),
+	fsparam_flag_no("rdirplus",	Opt_rdirplus),
+	fsparam_flag  ("rdma",		Opt_rdma),
+	fsparam_flag_no("resvport",	Opt_resvport),
+	fsparam_u32   ("retrans",	Opt_retrans),
+	fsparam_string("retry",		Opt_retry),
+	fsparam_u32   ("rsize",		Opt_rsize),
+	fsparam_string("sec",		Opt_sec),
+	fsparam_flag_no("sharecache",	Opt_sharecache),
+	fsparam_flag  ("sloppy",	Opt_sloppy),
+	fsparam_flag  ("soft",		Opt_soft),
+	fsparam_flag  ("softerr",	Opt_softerr),
+	fsparam_flag  ("softreval",	Opt_softreval),
+	fsparam_string("source",	Opt_source),
+	fsparam_flag  ("tcp",		Opt_tcp),
+	fsparam_u32   ("timeo",		Opt_timeo),
+	fsparam_flag_no("trunkdiscovery", Opt_trunkdiscovery),
+	fsparam_flag  ("udp",		Opt_udp),
+	fsparam_flag  ("v2",		Opt_v),
+	fsparam_flag  ("v3",		Opt_v),
+	fsparam_flag  ("v4",		Opt_v),
+	fsparam_flag  ("v4.0",		Opt_v),
+	fsparam_flag  ("v4.1",		Opt_v),
+	fsparam_flag  ("v4.2",		Opt_v),
+	fsparam_string("vers",		Opt_vers),
+	fsparam_enum  ("write",		Opt_write, nfs_param_enums_write),
+	fsparam_u32   ("wsize",		Opt_wsize),
+	{}
+};
+
+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[] = {
+	{ "rdma",	Opt_xprt_rdma },
+	{ "rdma6",	Opt_xprt_rdma6 },
+	{ "tcp",	Opt_xprt_tcp },
+	{ "tcp6",	Opt_xprt_tcp6 },
+	{ "udp",	Opt_xprt_udp },
+	{ "udp6",	Opt_xprt_udp6 },
+	{}
+};
+
+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 },
+	{}
+};
+
+/*
+ * 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_storage *addr)
+{
+	switch (addr->ss_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);
+	}
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_NFS_DISABLE_UDP_SUPPORT
+static bool nfs_server_transport_udp_invalid(const struct nfs_fs_context *ctx)
+{
+	return true;
+}
+#else
+static bool nfs_server_transport_udp_invalid(const struct nfs_fs_context *ctx)
+{
+	if (ctx->version == 4)
+		return true;
+	return false;
+}
+#endif
+
+/*
+ * Sanity check the NFS transport protocol.
+ */
+static int nfs_validate_transport_protocol(struct fs_context *fc,
+					   struct nfs_fs_context *ctx)
+{
+	switch (ctx->nfs_server.protocol) {
+	case XPRT_TRANSPORT_UDP:
+		if (nfs_server_transport_udp_invalid(ctx))
+			goto out_invalid_transport_udp;
+		break;
+	case XPRT_TRANSPORT_TCP:
+	case XPRT_TRANSPORT_RDMA:
+		break;
+	default:
+		ctx->nfs_server.protocol = XPRT_TRANSPORT_TCP;
+	}
+	return 0;
+out_invalid_transport_udp:
+	return nfs_invalf(fc, "NFS: Unsupported transport protocol udp");
+}
+
+/*
+ * 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)
+{
+	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;
+
+	trace_nfs_mount_assign(param->key, 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;
+
+	trace_nfs_mount_option(param);
+
+	opt = fs_parse(fc, nfs_fs_parameters, param, &result);
+	if (opt < 0)
+		return (opt == -ENOPARAM && ctx->sloppy) ? 1 : opt;
+
+	if (fc->security)
+		ctx->has_sec_mnt_opts = 1;
+
+	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;
+		ctx->flags &= ~NFS_MOUNT_SOFTERR;
+		break;
+	case Opt_softerr:
+		ctx->flags |= NFS_MOUNT_SOFTERR | NFS_MOUNT_SOFTREVAL;
+		ctx->flags &= ~NFS_MOUNT_SOFT;
+		break;
+	case Opt_hard:
+		ctx->flags &= ~(NFS_MOUNT_SOFT |
+				NFS_MOUNT_SOFTERR |
+				NFS_MOUNT_SOFTREVAL);
+		break;
+	case Opt_softreval:
+		if (result.negated)
+			ctx->flags &= ~NFS_MOUNT_SOFTREVAL;
+		else
+			ctx->flags |= NFS_MOUNT_SOFTREVAL;
+		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_trunkdiscovery:
+		if (result.negated)
+			ctx->flags &= ~NFS_MOUNT_TRUNK_DISCOVERY;
+		else
+			ctx->flags |= NFS_MOUNT_TRUNK_DISCOVERY;
+		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:
+	case Opt_rdma:
+		ctx->flags |= NFS_MOUNT_TCP; /* for side protocols */
+		ret = xprt_find_transport_ident(param->key);
+		if (ret < 0)
+			goto out_bad_transport;
+		ctx->nfs_server.protocol = ret;
+		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_flag:
+		if (result.negated)
+			ctx->options &= ~NFS_OPTION_FSCACHE;
+		else
+			ctx->options |= NFS_OPTION_FSCACHE;
+		kfree(ctx->fscache_uniq);
+		ctx->fscache_uniq = NULL;
+		break;
+	case Opt_fscache:
+		ctx->options |= NFS_OPTION_FSCACHE;
+		kfree(ctx->fscache_uniq);
+		ctx->fscache_uniq = param->string;
+		param->string = NULL;
+		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:
+		if (!param->string)
+			goto out_invalid_value;
+		trace_nfs_mount_assign(param->key, param->string);
+		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:
+		if (!param->string)
+			goto out_invalid_value;
+		trace_nfs_mount_assign(param->key, param->string);
+		protofamily = AF_INET;
+		switch (lookup_constant(nfs_xprt_protocol_tokens, param->string, -1)) {
+		case Opt_xprt_udp6:
+			protofamily = AF_INET6;
+			fallthrough;
+		case Opt_xprt_udp:
+			ctx->flags &= ~NFS_MOUNT_TCP;
+			ctx->nfs_server.protocol = XPRT_TRANSPORT_UDP;
+			break;
+		case Opt_xprt_tcp6:
+			protofamily = AF_INET6;
+			fallthrough;
+		case Opt_xprt_tcp:
+			ctx->flags |= NFS_MOUNT_TCP;
+			ctx->nfs_server.protocol = XPRT_TRANSPORT_TCP;
+			break;
+		case Opt_xprt_rdma6:
+			protofamily = AF_INET6;
+			fallthrough;
+		case Opt_xprt_rdma:
+			/* vector side protocols to TCP */
+			ctx->flags |= NFS_MOUNT_TCP;
+			ret = xprt_find_transport_ident(param->string);
+			if (ret < 0)
+				goto out_bad_transport;
+			ctx->nfs_server.protocol = ret;
+			break;
+		default:
+			goto out_bad_transport;
+		}
+
+		ctx->protofamily = protofamily;
+		break;
+
+	case Opt_mountproto:
+		if (!param->string)
+			goto out_invalid_value;
+		trace_nfs_mount_assign(param->key, param->string);
+		mountfamily = AF_INET;
+		switch (lookup_constant(nfs_xprt_protocol_tokens, param->string, -1)) {
+		case Opt_xprt_udp6:
+			mountfamily = AF_INET6;
+			fallthrough;
+		case Opt_xprt_udp:
+			ctx->mount_server.protocol = XPRT_TRANSPORT_UDP;
+			break;
+		case Opt_xprt_tcp6:
+			mountfamily = AF_INET6;
+			fallthrough;
+		case Opt_xprt_tcp:
+			ctx->mount_server.protocol = XPRT_TRANSPORT_TCP;
+			break;
+		case Opt_xprt_rdma: /* not used for side protocols */
+		default:
+			goto out_bad_transport;
+		}
+		ctx->mountfamily = mountfamily;
+		break;
+
+	case Opt_addr:
+		trace_nfs_mount_assign(param->key, param->string);
+		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:
+		trace_nfs_mount_assign(param->key, param->string);
+		kfree(ctx->client_address);
+		ctx->client_address = param->string;
+		param->string = NULL;
+		break;
+	case Opt_mounthost:
+		trace_nfs_mount_assign(param->key, param->string);
+		kfree(ctx->mount_server.hostname);
+		ctx->mount_server.hostname = param->string;
+		param->string = NULL;
+		break;
+	case Opt_mountaddr:
+		trace_nfs_mount_assign(param->key, param->string);
+		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_nconnect:
+		if (result.uint_32 < 1 || result.uint_32 > NFS_MAX_CONNECTIONS)
+			goto out_of_bounds;
+		ctx->nfs_server.nconnect = result.uint_32;
+		break;
+	case Opt_max_connect:
+		if (result.uint_32 < 1 || result.uint_32 > NFS_MAX_TRANSPORTS)
+			goto out_of_bounds;
+		ctx->nfs_server.max_connect = result.uint_32;
+		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;
+	case Opt_write:
+		switch (result.uint_32) {
+		case Opt_write_lazy:
+			ctx->flags &=
+				~(NFS_MOUNT_WRITE_EAGER | NFS_MOUNT_WRITE_WAIT);
+			break;
+		case Opt_write_eager:
+			ctx->flags |= NFS_MOUNT_WRITE_EAGER;
+			ctx->flags &= ~NFS_MOUNT_WRITE_WAIT;
+			break;
+		case Opt_write_wait:
+			ctx->flags |=
+				NFS_MOUNT_WRITE_EAGER | NFS_MOUNT_WRITE_WAIT;
+			break;
+		default:
+			goto out_invalid_value;
+		}
+		break;
+
+		/*
+		 * Special options
+		 */
+	case Opt_sloppy:
+		ctx->sloppy = true;
+		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:
+	return nfs_invalf(fc, "NFS: Value for '%s' out of range", param->key);
+out_bad_transport:
+	return nfs_invalf(fc, "NFS: Unrecognized transport protocol");
+}
+
+/*
+ * 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;
+
+	if (unlikely(!dev_name || !*dev_name))
+		return -EINVAL;
+
+	/* 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;
+
+	kfree(ctx->nfs_server.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;
+
+	trace_nfs_mount_path(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;
+}
+
+static inline bool is_remount_fc(struct fs_context *fc)
+{
+	return fc->root != NULL;
+}
+
+/*
+ * 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_storage *sap = &ctx->nfs_server._address;
+	int extra_flags = NFS_MOUNT_LEGACY_INTERFACE;
+	int ret;
+
+	if (data == NULL)
+		goto out_no_data;
+
+	ctx->version = NFS_DEFAULT_VERSION;
+	switch (data->version) {
+	case 1:
+		data->namlen = 0;
+		fallthrough;
+	case 2:
+		data->bsize = 0;
+		fallthrough;
+	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;
+		fallthrough;
+	case 4:
+		if (data->flags & NFS_MOUNT_SECFLAVOUR)
+			goto out_no_sec;
+		fallthrough;
+	case 5:
+		memset(data->context, 0, sizeof(data->context));
+		fallthrough;
+	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);
+
+		/*
+		 * for proto == XPRT_TRANSPORT_UDP, which is what uses
+		 * to_exponential, implying shift: limit the shift value
+		 * to BITS_PER_LONG (majortimeo is unsigned long)
+		 */
+		if (!(data->flags & NFS_MOUNT_TCP)) /* this will be UDP */
+			if (data->retrans >= 64) /* shift value is too large */
+				goto out_invalid_data;
+
+		/*
+		 * 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 (sap->ss_family != AF_INET ||
+		    !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
+		 * 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;
+	}
+
+	ret = nfs_validate_transport_protocol(fc, ctx);
+	if (ret)
+		return ret;
+
+	ctx->skip_reconfig_option_check = true;
+	return 0;
+
+generic:
+	return generic_parse_monolithic(fc, data);
+
+out_no_data:
+	if (is_remount_fc(fc)) {
+		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:
+	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");
+
+out_invalid_data:
+	return nfs_invalf(fc, "NFS: invalid binary mount data");
+}
+
+#if IS_ENABLED(CONFIG_NFS_V4)
+struct compat_nfs_string {
+	compat_uint_t len;
+	compat_uptr_t data;
+};
+
+static inline void compat_nfs_string(struct nfs_string *dst,
+				     struct compat_nfs_string *src)
+{
+	dst->data = compat_ptr(src->data);
+	dst->len = src->len;
+}
+
+struct compat_nfs4_mount_data_v1 {
+	compat_int_t version;
+	compat_int_t flags;
+	compat_int_t rsize;
+	compat_int_t wsize;
+	compat_int_t timeo;
+	compat_int_t retrans;
+	compat_int_t acregmin;
+	compat_int_t acregmax;
+	compat_int_t acdirmin;
+	compat_int_t acdirmax;
+	struct compat_nfs_string client_addr;
+	struct compat_nfs_string mnt_path;
+	struct compat_nfs_string hostname;
+	compat_uint_t host_addrlen;
+	compat_uptr_t host_addr;
+	compat_int_t proto;
+	compat_int_t auth_flavourlen;
+	compat_uptr_t auth_flavours;
+};
+
+static void nfs4_compat_mount_data_conv(struct nfs4_mount_data *data)
+{
+	struct compat_nfs4_mount_data_v1 *compat =
+			(struct compat_nfs4_mount_data_v1 *)data;
+
+	/* copy the fields backwards */
+	data->auth_flavours = compat_ptr(compat->auth_flavours);
+	data->auth_flavourlen = compat->auth_flavourlen;
+	data->proto = compat->proto;
+	data->host_addr = compat_ptr(compat->host_addr);
+	data->host_addrlen = compat->host_addrlen;
+	compat_nfs_string(&data->hostname, &compat->hostname);
+	compat_nfs_string(&data->mnt_path, &compat->mnt_path);
+	compat_nfs_string(&data->client_addr, &compat->client_addr);
+	data->acdirmax = compat->acdirmax;
+	data->acdirmin = compat->acdirmin;
+	data->acregmax = compat->acregmax;
+	data->acregmin = compat->acregmin;
+	data->retrans = compat->retrans;
+	data->timeo = compat->timeo;
+	data->wsize = compat->wsize;
+	data->rsize = compat->rsize;
+	data->flags = compat->flags;
+	data->version = compat->version;
+}
+
+/*
+ * 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_storage *sap = &ctx->nfs_server._address;
+	int ret;
+	char *c;
+
+	if (!data) {
+		if (is_remount_fc(fc))
+			goto done;
+		return nfs_invalf(fc,
+			"NFS4: mount program didn't pass any mount data");
+	}
+
+	ctx->version = 4;
+
+	if (data->version != 1)
+		return generic_parse_monolithic(fc, data);
+
+	if (in_compat_syscall())
+		nfs4_compat_mount_data_conv(data);
+
+	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;
+	trace_nfs_mount_path(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;
+	ret = nfs_validate_transport_protocol(fc, ctx);
+	if (ret)
+		return ret;
+done:
+	ctx->skip_reconfig_option_check = true;
+	return 0;
+
+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");
+}
+#endif
+
+/*
+ * 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_storage *sap = &ctx->nfs_server._address;
+	int max_namelen = PAGE_SIZE;
+	int max_pathlen = NFS_MAXPATHLEN;
+	int port = 0;
+	int ret;
+
+	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;
+
+	ret = nfs_validate_transport_protocol(fc, ctx);
+	if (ret)
+		return ret;
+
+	if (ctx->version == 4) {
+		if (IS_ENABLED(CONFIG_NFS_V4)) {
+			if (ctx->nfs_server.protocol == XPRT_TRANSPORT_RDMA)
+				port = NFS_RDMA_PORT;
+			else
+				port = NFS_PORT;
+			max_namelen = NFS4_MAXNAMLEN;
+			max_pathlen = NFS4_MAXPATHLEN;
+			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);
+		if (ctx->nfs_server.protocol == XPRT_TRANSPORT_RDMA)
+			port = NFS_RDMA_PORT;
+	}
+
+	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;
+	}
+
+	/* Ensure the filesystem context has the correct fs_type */
+	if (fc->fs_type != ctx->nfs_mod->nfs_fs) {
+		module_put(fc->fs_type->owner);
+		__module_get(ctx->nfs_mod->nfs_fs->owner);
+		fc->fs_type = ctx->nfs_mod->nfs_fs;
+	}
+	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_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;
+}
+
+/*
+ * 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 err = nfs_fs_context_validate(fc);
+
+	if (err)
+		return err;
+	if (!ctx->internal)
+		return ctx->nfs_mod->rpc_ops->try_get_tree(fc);
+	else
+		return nfs_get_tree_common(fc);
+}
+
+/*
+ * 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) {
+		kfree(ctx);
+		return -ENOMEM;
+	}
+	nfs_copy_fh(ctx->mntfh, src->mntfh);
+
+	__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;
+	ctx->clone_data.fattr		= 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->server)
+			nfs_free_server(ctx->server);
+		if (ctx->nfs_mod)
+			put_nfs_version(ctx->nfs_mod);
+		kfree(ctx->client_address);
+		kfree(ctx->mount_server.hostname);
+		kfree(ctx->nfs_server.export_path);
+		kfree(ctx->nfs_server.hostname);
+		kfree(ctx->fscache_uniq);
+		nfs_free_fhandle(ctx->mntfh);
+		nfs_free_fattr(ctx->clone_data.fattr);
+		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,
+	.get_tree		= nfs_get_tree,
+	.reconfigure		= nfs_reconfigure,
+};
+
+/*
+ * 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 nfs_fs_context *ctx;
+
+	ctx = kzalloc(sizeof(struct nfs_fs_context), GFP_KERNEL);
+	if (unlikely(!ctx))
+		return -ENOMEM;
+
+	ctx->mntfh = nfs_alloc_fhandle();
+	if (unlikely(!ctx->mntfh)) {
+		kfree(ctx);
+		return -ENOMEM;
+	}
+
+	ctx->protofamily	= AF_UNSPEC;
+	ctx->mountfamily	= AF_UNSPEC;
+	ctx->mount_server.port	= NFS_UNSPEC_PORT;
+
+	if (fc->root) {
+		/* reconfigure, start with the current config */
+		struct nfs_server *nfss = fc->root->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;
+		__module_get(ctx->nfs_mod->owner);
+	} else {
+		/* defaults */
+		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;
+
+		fc->s_iflags		|= SB_I_STABLE_WRITES;
+	}
+	fc->fs_private = ctx;
+	fc->ops = &nfs_fs_context_ops;
+	return 0;
+}
+
+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 */