[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit

Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/fs/nfs/super.c b/ap/os/linux/linux-3.4.x/fs/nfs/super.c
new file mode 100644
index 0000000..c252161
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/fs/nfs/super.c
@@ -0,0 +1,3153 @@
+/*
+ *  linux/fs/nfs/super.c
+ *
+ *  Copyright (C) 1992  Rick Sladkey
+ *
+ *  nfs superblock handling functions
+ *
+ *  Modularised by Alan Cox <alan@lxorguk.ukuu.org.uk>, while hacking some
+ *  experimental NFS changes. Modularisation taken straight from SYS5 fs.
+ *
+ *  Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
+ *  J.S.Peatfield@damtp.cam.ac.uk
+ *
+ *  Split from inode.c by David Howells <dhowells@redhat.com>
+ *
+ * - superblocks are indexed on server only - all inodes, dentries, etc. associated with a
+ *   particular server are held in the same superblock
+ * - NFS superblocks can have several effective roots to the dentry tree
+ * - directory type roots are spliced into the tree when a path from one root reaches the root
+ *   of another (see nfs_lookup())
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+
+#include <linux/time.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/unistd.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/stats.h>
+#include <linux/sunrpc/metrics.h>
+#include <linux/sunrpc/xprtsock.h>
+#include <linux/sunrpc/xprtrdma.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/nfs4_mount.h>
+#include <linux/lockd/bind.h>
+#include <linux/seq_file.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/nfs_idmap.h>
+#include <linux/vfs.h>
+#include <linux/inet.h>
+#include <linux/in6.h>
+#include <linux/slab.h>
+#include <net/ipv6.h>
+#include <linux/netdevice.h>
+#include <linux/nfs_xdr.h>
+#include <linux/magic.h>
+#include <linux/parser.h>
+#include <linux/nsproxy.h>
+#include <linux/rcupdate.h>
+
+#include <asm/uaccess.h>
+
+#include "nfs4_fs.h"
+#include "callback.h"
+#include "delegation.h"
+#include "iostat.h"
+#include "internal.h"
+#include "fscache.h"
+#include "pnfs.h"
+
+#define NFSDBG_FACILITY		NFSDBG_VFS
+
+#ifdef CONFIG_NFS_V3
+#define NFS_DEFAULT_VERSION 3
+#else
+#define NFS_DEFAULT_VERSION 2
+#endif
+
+enum {
+	/* Mount options that take no arguments */
+	Opt_soft, Opt_hard,
+	Opt_posix, Opt_noposix,
+	Opt_cto, Opt_nocto,
+	Opt_ac, Opt_noac,
+	Opt_lock, Opt_nolock,
+	Opt_udp, Opt_tcp, Opt_rdma,
+	Opt_acl, Opt_noacl,
+	Opt_rdirplus, Opt_nordirplus,
+	Opt_sharecache, Opt_nosharecache,
+	Opt_resvport, Opt_noresvport,
+	Opt_fscache, Opt_nofscache,
+
+	/* Mount options that take integer arguments */
+	Opt_port,
+	Opt_rsize, Opt_wsize, Opt_bsize,
+	Opt_timeo, Opt_retrans,
+	Opt_acregmin, Opt_acregmax,
+	Opt_acdirmin, Opt_acdirmax,
+	Opt_actimeo,
+	Opt_namelen,
+	Opt_mountport,
+	Opt_mountvers,
+	Opt_minorversion,
+
+	/* Mount options that take string arguments */
+	Opt_nfsvers,
+	Opt_sec, Opt_proto, Opt_mountproto, Opt_mounthost,
+	Opt_addr, Opt_mountaddr, Opt_clientaddr,
+	Opt_lookupcache,
+	Opt_fscache_uniq,
+	Opt_local_lock,
+
+	/* Special mount options */
+	Opt_userspace, Opt_deprecated, Opt_sloppy,
+
+	Opt_err
+};
+
+static const match_table_t nfs_mount_option_tokens = {
+	{ Opt_userspace, "bg" },
+	{ Opt_userspace, "fg" },
+	{ Opt_userspace, "retry=%s" },
+
+	{ Opt_sloppy, "sloppy" },
+
+	{ Opt_soft, "soft" },
+	{ Opt_hard, "hard" },
+	{ Opt_deprecated, "intr" },
+	{ Opt_deprecated, "nointr" },
+	{ Opt_posix, "posix" },
+	{ Opt_noposix, "noposix" },
+	{ Opt_cto, "cto" },
+	{ Opt_nocto, "nocto" },
+	{ Opt_ac, "ac" },
+	{ Opt_noac, "noac" },
+	{ Opt_lock, "lock" },
+	{ Opt_nolock, "nolock" },
+	{ Opt_udp, "udp" },
+	{ Opt_tcp, "tcp" },
+	{ Opt_rdma, "rdma" },
+	{ Opt_acl, "acl" },
+	{ Opt_noacl, "noacl" },
+	{ Opt_rdirplus, "rdirplus" },
+	{ Opt_nordirplus, "nordirplus" },
+	{ Opt_sharecache, "sharecache" },
+	{ Opt_nosharecache, "nosharecache" },
+	{ Opt_resvport, "resvport" },
+	{ Opt_noresvport, "noresvport" },
+	{ Opt_fscache, "fsc" },
+	{ Opt_nofscache, "nofsc" },
+
+	{ Opt_port, "port=%s" },
+	{ Opt_rsize, "rsize=%s" },
+	{ Opt_wsize, "wsize=%s" },
+	{ Opt_bsize, "bsize=%s" },
+	{ Opt_timeo, "timeo=%s" },
+	{ Opt_retrans, "retrans=%s" },
+	{ Opt_acregmin, "acregmin=%s" },
+	{ Opt_acregmax, "acregmax=%s" },
+	{ Opt_acdirmin, "acdirmin=%s" },
+	{ Opt_acdirmax, "acdirmax=%s" },
+	{ Opt_actimeo, "actimeo=%s" },
+	{ Opt_namelen, "namlen=%s" },
+	{ Opt_mountport, "mountport=%s" },
+	{ Opt_mountvers, "mountvers=%s" },
+	{ Opt_minorversion, "minorversion=%s" },
+
+	{ Opt_nfsvers, "nfsvers=%s" },
+	{ Opt_nfsvers, "vers=%s" },
+
+	{ Opt_sec, "sec=%s" },
+	{ Opt_proto, "proto=%s" },
+	{ Opt_mountproto, "mountproto=%s" },
+	{ Opt_addr, "addr=%s" },
+	{ Opt_clientaddr, "clientaddr=%s" },
+	{ Opt_mounthost, "mounthost=%s" },
+	{ Opt_mountaddr, "mountaddr=%s" },
+
+	{ Opt_lookupcache, "lookupcache=%s" },
+	{ Opt_fscache_uniq, "fsc=%s" },
+	{ Opt_local_lock, "local_lock=%s" },
+
+	/* The following needs to be listed after all other options */
+	{ Opt_nfsvers, "v%s" },
+
+	{ Opt_err, NULL }
+};
+
+enum {
+	Opt_xprt_udp, Opt_xprt_udp6, Opt_xprt_tcp, Opt_xprt_tcp6, Opt_xprt_rdma,
+
+	Opt_xprt_err
+};
+
+static const match_table_t nfs_xprt_protocol_tokens = {
+	{ Opt_xprt_udp, "udp" },
+	{ Opt_xprt_udp6, "udp6" },
+	{ Opt_xprt_tcp, "tcp" },
+	{ Opt_xprt_tcp6, "tcp6" },
+	{ Opt_xprt_rdma, "rdma" },
+
+	{ Opt_xprt_err, NULL }
+};
+
+enum {
+	Opt_sec_none, Opt_sec_sys,
+	Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
+	Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
+	Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
+
+	Opt_sec_err
+};
+
+static const match_table_t nfs_secflavor_tokens = {
+	{ Opt_sec_none, "none" },
+	{ Opt_sec_none, "null" },
+	{ Opt_sec_sys, "sys" },
+
+	{ Opt_sec_krb5, "krb5" },
+	{ Opt_sec_krb5i, "krb5i" },
+	{ Opt_sec_krb5p, "krb5p" },
+
+	{ Opt_sec_lkey, "lkey" },
+	{ Opt_sec_lkeyi, "lkeyi" },
+	{ Opt_sec_lkeyp, "lkeyp" },
+
+	{ Opt_sec_spkm, "spkm3" },
+	{ Opt_sec_spkmi, "spkm3i" },
+	{ Opt_sec_spkmp, "spkm3p" },
+
+	{ Opt_sec_err, NULL }
+};
+
+enum {
+	Opt_lookupcache_all, Opt_lookupcache_positive,
+	Opt_lookupcache_none,
+
+	Opt_lookupcache_err
+};
+
+static match_table_t nfs_lookupcache_tokens = {
+	{ Opt_lookupcache_all, "all" },
+	{ Opt_lookupcache_positive, "pos" },
+	{ Opt_lookupcache_positive, "positive" },
+	{ Opt_lookupcache_none, "none" },
+
+	{ Opt_lookupcache_err, NULL }
+};
+
+enum {
+	Opt_local_lock_all, Opt_local_lock_flock, Opt_local_lock_posix,
+	Opt_local_lock_none,
+
+	Opt_local_lock_err
+};
+
+static match_table_t nfs_local_lock_tokens = {
+	{ Opt_local_lock_all, "all" },
+	{ Opt_local_lock_flock, "flock" },
+	{ Opt_local_lock_posix, "posix" },
+	{ Opt_local_lock_none, "none" },
+
+	{ Opt_local_lock_err, NULL }
+};
+
+enum {
+	Opt_vers_2, Opt_vers_3, Opt_vers_4, Opt_vers_4_0,
+	Opt_vers_4_1,
+
+	Opt_vers_err
+};
+
+static match_table_t nfs_vers_tokens = {
+	{ Opt_vers_2, "2" },
+	{ Opt_vers_3, "3" },
+	{ Opt_vers_4, "4" },
+	{ Opt_vers_4_0, "4.0" },
+	{ Opt_vers_4_1, "4.1" },
+
+	{ Opt_vers_err, NULL }
+};
+
+static void nfs_umount_begin(struct super_block *);
+static int  nfs_statfs(struct dentry *, struct kstatfs *);
+static int  nfs_show_options(struct seq_file *, struct dentry *);
+static int  nfs_show_devname(struct seq_file *, struct dentry *);
+static int  nfs_show_path(struct seq_file *, struct dentry *);
+static int  nfs_show_stats(struct seq_file *, struct dentry *);
+static struct dentry *nfs_fs_mount(struct file_system_type *,
+		int, const char *, void *);
+static struct dentry *nfs_xdev_mount(struct file_system_type *fs_type,
+		int flags, const char *dev_name, void *raw_data);
+static void nfs_put_super(struct super_block *);
+static void nfs_kill_super(struct super_block *);
+static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
+
+static struct file_system_type nfs_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "nfs",
+	.mount		= nfs_fs_mount,
+	.kill_sb	= nfs_kill_super,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
+struct file_system_type nfs_xdev_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "nfs",
+	.mount		= nfs_xdev_mount,
+	.kill_sb	= nfs_kill_super,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
+static const struct super_operations nfs_sops = {
+	.alloc_inode	= nfs_alloc_inode,
+	.destroy_inode	= nfs_destroy_inode,
+	.write_inode	= nfs_write_inode,
+	.put_super	= nfs_put_super,
+	.statfs		= nfs_statfs,
+	.evict_inode	= nfs_evict_inode,
+	.umount_begin	= nfs_umount_begin,
+	.show_options	= nfs_show_options,
+	.show_devname	= nfs_show_devname,
+	.show_path	= nfs_show_path,
+	.show_stats	= nfs_show_stats,
+	.remount_fs	= nfs_remount,
+};
+
+#ifdef CONFIG_NFS_V4
+static int nfs4_validate_text_mount_data(void *options,
+	struct nfs_parsed_mount_data *args, const char *dev_name);
+static struct dentry *nfs4_try_mount(int flags, const char *dev_name,
+	struct nfs_parsed_mount_data *data);
+static struct dentry *nfs4_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *raw_data);
+static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *raw_data);
+static struct dentry *nfs4_xdev_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *raw_data);
+static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *raw_data);
+static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *raw_data);
+static void nfs4_kill_super(struct super_block *sb);
+
+static struct file_system_type nfs4_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "nfs4",
+	.mount		= nfs4_mount,
+	.kill_sb	= nfs4_kill_super,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
+static struct file_system_type nfs4_remote_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "nfs4",
+	.mount		= nfs4_remote_mount,
+	.kill_sb	= nfs4_kill_super,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
+struct file_system_type nfs4_xdev_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "nfs4",
+	.mount		= nfs4_xdev_mount,
+	.kill_sb	= nfs4_kill_super,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
+static struct file_system_type nfs4_remote_referral_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "nfs4",
+	.mount		= nfs4_remote_referral_mount,
+	.kill_sb	= nfs4_kill_super,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
+struct file_system_type nfs4_referral_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "nfs4",
+	.mount		= nfs4_referral_mount,
+	.kill_sb	= nfs4_kill_super,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
+static const struct super_operations nfs4_sops = {
+	.alloc_inode	= nfs_alloc_inode,
+	.destroy_inode	= nfs_destroy_inode,
+	.write_inode	= nfs_write_inode,
+	.put_super	= nfs_put_super,
+	.statfs		= nfs_statfs,
+	.evict_inode	= nfs4_evict_inode,
+	.umount_begin	= nfs_umount_begin,
+	.show_options	= nfs_show_options,
+	.show_devname	= nfs_show_devname,
+	.show_path	= nfs_show_path,
+	.show_stats	= nfs_show_stats,
+	.remount_fs	= nfs_remount,
+};
+#endif
+
+static struct shrinker acl_shrinker = {
+	.shrink		= nfs_access_cache_shrinker,
+	.seeks		= DEFAULT_SEEKS,
+};
+
+/*
+ * Register the NFS filesystems
+ */
+int __init register_nfs_fs(void)
+{
+	int ret;
+
+        ret = register_filesystem(&nfs_fs_type);
+	if (ret < 0)
+		goto error_0;
+
+	ret = nfs_register_sysctl();
+	if (ret < 0)
+		goto error_1;
+#ifdef CONFIG_NFS_V4
+	ret = register_filesystem(&nfs4_fs_type);
+	if (ret < 0)
+		goto error_2;
+#endif
+	register_shrinker(&acl_shrinker);
+	return 0;
+
+#ifdef CONFIG_NFS_V4
+error_2:
+	nfs_unregister_sysctl();
+#endif
+error_1:
+	unregister_filesystem(&nfs_fs_type);
+error_0:
+	return ret;
+}
+
+/*
+ * Unregister the NFS filesystems
+ */
+void __exit unregister_nfs_fs(void)
+{
+	unregister_shrinker(&acl_shrinker);
+#ifdef CONFIG_NFS_V4
+	unregister_filesystem(&nfs4_fs_type);
+#endif
+	nfs_unregister_sysctl();
+	unregister_filesystem(&nfs_fs_type);
+}
+
+void nfs_sb_active(struct super_block *sb)
+{
+	struct nfs_server *server = NFS_SB(sb);
+
+	if (atomic_inc_return(&server->active) == 1)
+		atomic_inc(&sb->s_active);
+}
+
+void nfs_sb_deactive(struct super_block *sb)
+{
+	struct nfs_server *server = NFS_SB(sb);
+
+	if (atomic_dec_and_test(&server->active))
+		deactivate_super(sb);
+}
+
+/*
+ * Deliver file system statistics to userspace
+ */
+static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct nfs_server *server = NFS_SB(dentry->d_sb);
+	unsigned char blockbits;
+	unsigned long blockres;
+	struct nfs_fh *fh = NFS_FH(dentry->d_inode);
+	struct nfs_fsstat res;
+	int error = -ENOMEM;
+
+	res.fattr = nfs_alloc_fattr();
+	if (res.fattr == NULL)
+		goto out_err;
+
+	error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
+	if (unlikely(error == -ESTALE)) {
+		struct dentry *pd_dentry;
+
+		pd_dentry = dget_parent(dentry);
+		if (pd_dentry != NULL) {
+			nfs_zap_caches(pd_dentry->d_inode);
+			dput(pd_dentry);
+		}
+	}
+	nfs_free_fattr(res.fattr);
+	if (error < 0)
+		goto out_err;
+
+	buf->f_type = NFS_SUPER_MAGIC;
+
+	/*
+	 * Current versions of glibc do not correctly handle the
+	 * case where f_frsize != f_bsize.  Eventually we want to
+	 * report the value of wtmult in this field.
+	 */
+	buf->f_frsize = dentry->d_sb->s_blocksize;
+
+	/*
+	 * On most *nix systems, f_blocks, f_bfree, and f_bavail
+	 * are reported in units of f_frsize.  Linux hasn't had
+	 * an f_frsize field in its statfs struct until recently,
+	 * thus historically Linux's sys_statfs reports these
+	 * fields in units of f_bsize.
+	 */
+	buf->f_bsize = dentry->d_sb->s_blocksize;
+	blockbits = dentry->d_sb->s_blocksize_bits;
+	blockres = (1 << blockbits) - 1;
+	buf->f_blocks = (res.tbytes + blockres) >> blockbits;
+	buf->f_bfree = (res.fbytes + blockres) >> blockbits;
+	buf->f_bavail = (res.abytes + blockres) >> blockbits;
+
+	buf->f_files = res.tfiles;
+	buf->f_ffree = res.afiles;
+
+	buf->f_namelen = server->namelen;
+
+	return 0;
+
+ out_err:
+	dprintk("%s: statfs error = %d\n", __func__, -error);
+	return error;
+}
+
+/*
+ * Map the security flavour number to a name
+ */
+static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
+{
+	static const struct {
+		rpc_authflavor_t flavour;
+		const char *str;
+	} sec_flavours[] = {
+		{ RPC_AUTH_NULL, "null" },
+		{ RPC_AUTH_UNIX, "sys" },
+		{ RPC_AUTH_GSS_KRB5, "krb5" },
+		{ RPC_AUTH_GSS_KRB5I, "krb5i" },
+		{ RPC_AUTH_GSS_KRB5P, "krb5p" },
+		{ RPC_AUTH_GSS_LKEY, "lkey" },
+		{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
+		{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
+		{ RPC_AUTH_GSS_SPKM, "spkm" },
+		{ RPC_AUTH_GSS_SPKMI, "spkmi" },
+		{ RPC_AUTH_GSS_SPKMP, "spkmp" },
+		{ UINT_MAX, "unknown" }
+	};
+	int i;
+
+	for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
+		if (sec_flavours[i].flavour == flavour)
+			break;
+	}
+	return sec_flavours[i].str;
+}
+
+static void nfs_show_mountd_netid(struct seq_file *m, struct nfs_server *nfss,
+				  int showdefaults)
+{
+	struct sockaddr *sap = (struct sockaddr *) &nfss->mountd_address;
+
+	seq_printf(m, ",mountproto=");
+	switch (sap->sa_family) {
+	case AF_INET:
+		switch (nfss->mountd_protocol) {
+		case IPPROTO_UDP:
+			seq_printf(m, RPCBIND_NETID_UDP);
+			break;
+		case IPPROTO_TCP:
+			seq_printf(m, RPCBIND_NETID_TCP);
+			break;
+		default:
+			if (showdefaults)
+				seq_printf(m, "auto");
+		}
+		break;
+	case AF_INET6:
+		switch (nfss->mountd_protocol) {
+		case IPPROTO_UDP:
+			seq_printf(m, RPCBIND_NETID_UDP6);
+			break;
+		case IPPROTO_TCP:
+			seq_printf(m, RPCBIND_NETID_TCP6);
+			break;
+		default:
+			if (showdefaults)
+				seq_printf(m, "auto");
+		}
+		break;
+	default:
+		if (showdefaults)
+			seq_printf(m, "auto");
+	}
+}
+
+static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
+				    int showdefaults)
+{
+	struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
+
+	if (nfss->flags & NFS_MOUNT_LEGACY_INTERFACE)
+		return;
+
+	switch (sap->sa_family) {
+	case AF_INET: {
+		struct sockaddr_in *sin = (struct sockaddr_in *)sap;
+		seq_printf(m, ",mountaddr=%pI4", &sin->sin_addr.s_addr);
+		break;
+	}
+	case AF_INET6: {
+		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
+		seq_printf(m, ",mountaddr=%pI6c", &sin6->sin6_addr);
+		break;
+	}
+	default:
+		if (showdefaults)
+			seq_printf(m, ",mountaddr=unspecified");
+	}
+
+	if (nfss->mountd_version || showdefaults)
+		seq_printf(m, ",mountvers=%u", nfss->mountd_version);
+	if ((nfss->mountd_port &&
+		nfss->mountd_port != (unsigned short)NFS_UNSPEC_PORT) ||
+		showdefaults)
+		seq_printf(m, ",mountport=%u", nfss->mountd_port);
+
+	nfs_show_mountd_netid(m, nfss, showdefaults);
+}
+
+#ifdef CONFIG_NFS_V4
+static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
+				    int showdefaults)
+{
+	struct nfs_client *clp = nfss->nfs_client;
+
+	seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
+}
+#else
+static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
+				    int showdefaults)
+{
+}
+#endif
+
+static void nfs_show_nfs_version(struct seq_file *m,
+		unsigned int version,
+		unsigned int minorversion)
+{
+	seq_printf(m, ",vers=%u", version);
+	if (version == 4)
+		seq_printf(m, ".%u", minorversion);
+}
+
+/*
+ * Describe the mount options in force on this server representation
+ */
+static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
+				   int showdefaults)
+{
+	static const struct proc_nfs_info {
+		int flag;
+		const char *str;
+		const char *nostr;
+	} nfs_info[] = {
+		{ NFS_MOUNT_SOFT, ",soft", ",hard" },
+		{ NFS_MOUNT_POSIX, ",posix", "" },
+		{ NFS_MOUNT_NOCTO, ",nocto", "" },
+		{ NFS_MOUNT_NOAC, ",noac", "" },
+		{ NFS_MOUNT_NONLM, ",nolock", "" },
+		{ NFS_MOUNT_NOACL, ",noacl", "" },
+		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
+		{ NFS_MOUNT_UNSHARED, ",nosharecache", "" },
+		{ NFS_MOUNT_NORESVPORT, ",noresvport", "" },
+		{ 0, NULL, NULL }
+	};
+	const struct proc_nfs_info *nfs_infop;
+	struct nfs_client *clp = nfss->nfs_client;
+	u32 version = clp->rpc_ops->version;
+	int local_flock, local_fcntl;
+
+	nfs_show_nfs_version(m, version, clp->cl_minorversion);
+	seq_printf(m, ",rsize=%u", nfss->rsize);
+	seq_printf(m, ",wsize=%u", nfss->wsize);
+	if (nfss->bsize != 0)
+		seq_printf(m, ",bsize=%u", nfss->bsize);
+	seq_printf(m, ",namlen=%u", nfss->namelen);
+	if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
+		seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
+	if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
+		seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
+	if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
+		seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
+	if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
+		seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
+	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
+		if (nfss->flags & nfs_infop->flag)
+			seq_puts(m, nfs_infop->str);
+		else
+			seq_puts(m, nfs_infop->nostr);
+	}
+	rcu_read_lock();
+	seq_printf(m, ",proto=%s",
+		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
+	rcu_read_unlock();
+	if (version == 4) {
+		if (nfss->port != NFS_PORT)
+			seq_printf(m, ",port=%u", nfss->port);
+	} else
+		if (nfss->port)
+			seq_printf(m, ",port=%u", nfss->port);
+
+	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
+	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
+	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
+
+	if (version != 4)
+		nfs_show_mountd_options(m, nfss, showdefaults);
+	else
+		nfs_show_nfsv4_options(m, nfss, showdefaults);
+
+	if (nfss->options & NFS_OPTION_FSCACHE)
+		seq_printf(m, ",fsc");
+
+	if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
+		if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
+			seq_printf(m, ",lookupcache=none");
+		else
+			seq_printf(m, ",lookupcache=pos");
+	}
+
+	local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
+	local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
+
+	if (!local_flock && !local_fcntl)
+		seq_printf(m, ",local_lock=none");
+	else if (local_flock && local_fcntl)
+		seq_printf(m, ",local_lock=all");
+	else if (local_flock)
+		seq_printf(m, ",local_lock=flock");
+	else
+		seq_printf(m, ",local_lock=posix");
+}
+
+/*
+ * Describe the mount options on this VFS mountpoint
+ */
+static int nfs_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct nfs_server *nfss = NFS_SB(root->d_sb);
+
+	nfs_show_mount_options(m, nfss, 0);
+
+	rcu_read_lock();
+	seq_printf(m, ",addr=%s",
+			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
+							RPC_DISPLAY_ADDR));
+	rcu_read_unlock();
+
+	return 0;
+}
+
+#ifdef CONFIG_NFS_V4
+#ifdef CONFIG_NFS_V4_1
+static void show_sessions(struct seq_file *m, struct nfs_server *server)
+{
+	if (nfs4_has_session(server->nfs_client))
+		seq_printf(m, ",sessions");
+}
+#else
+static void show_sessions(struct seq_file *m, struct nfs_server *server) {}
+#endif
+#endif
+
+#ifdef CONFIG_NFS_V4_1
+static void show_pnfs(struct seq_file *m, struct nfs_server *server)
+{
+	seq_printf(m, ",pnfs=");
+	if (server->pnfs_curr_ld)
+		seq_printf(m, "%s", server->pnfs_curr_ld->name);
+	else
+		seq_printf(m, "not configured");
+}
+
+static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
+{
+	if (nfss->nfs_client && nfss->nfs_client->impl_id) {
+		struct nfs41_impl_id *impl_id = nfss->nfs_client->impl_id;
+		seq_printf(m, "\n\timpl_id:\tname='%s',domain='%s',"
+			   "date='%llu,%u'",
+			   impl_id->name, impl_id->domain,
+			   impl_id->date.seconds, impl_id->date.nseconds);
+	}
+}
+#else
+#ifdef CONFIG_NFS_V4
+static void show_pnfs(struct seq_file *m, struct nfs_server *server)
+{
+}
+#endif
+static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
+{
+}
+#endif
+
+static int nfs_show_devname(struct seq_file *m, struct dentry *root)
+{
+	char *page = (char *) __get_free_page(GFP_KERNEL);
+	char *devname, *dummy;
+	int err = 0;
+	if (!page)
+		return -ENOMEM;
+	devname = nfs_path(&dummy, root, page, PAGE_SIZE, 0);
+	if (IS_ERR(devname))
+		err = PTR_ERR(devname);
+	else
+		seq_escape(m, devname, " \t\n\\");
+	free_page((unsigned long)page);
+	return err;
+}
+
+static int nfs_show_path(struct seq_file *m, struct dentry *dentry)
+{
+	seq_puts(m, "/");
+	return 0;
+}
+
+/*
+ * Present statistical information for this VFS mountpoint
+ */
+static int nfs_show_stats(struct seq_file *m, struct dentry *root)
+{
+	int i, cpu;
+	struct nfs_server *nfss = NFS_SB(root->d_sb);
+	struct rpc_auth *auth = nfss->client->cl_auth;
+	struct nfs_iostats totals = { };
+
+	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
+
+	/*
+	 * Display all mount option settings
+	 */
+	seq_printf(m, "\n\topts:\t");
+	seq_puts(m, root->d_sb->s_flags & MS_RDONLY ? "ro" : "rw");
+	seq_puts(m, root->d_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
+	seq_puts(m, root->d_sb->s_flags & MS_NOATIME ? ",noatime" : "");
+	seq_puts(m, root->d_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
+	nfs_show_mount_options(m, nfss, 1);
+
+	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
+
+	show_implementation_id(m, nfss);
+
+	seq_printf(m, "\n\tcaps:\t");
+	seq_printf(m, "caps=0x%x", nfss->caps);
+	seq_printf(m, ",wtmult=%u", nfss->wtmult);
+	seq_printf(m, ",dtsize=%u", nfss->dtsize);
+	seq_printf(m, ",bsize=%u", nfss->bsize);
+	seq_printf(m, ",namlen=%u", nfss->namelen);
+
+#ifdef CONFIG_NFS_V4
+	if (nfss->nfs_client->rpc_ops->version == 4) {
+		seq_printf(m, "\n\tnfsv4:\t");
+		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
+		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
+		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
+		show_sessions(m, nfss);
+		show_pnfs(m, nfss);
+	}
+#endif
+
+	/*
+	 * Display security flavor in effect for this mount
+	 */
+	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
+	if (auth->au_flavor)
+		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
+
+	/*
+	 * Display superblock I/O counters
+	 */
+	for_each_possible_cpu(cpu) {
+		struct nfs_iostats *stats;
+
+		preempt_disable();
+		stats = per_cpu_ptr(nfss->io_stats, cpu);
+
+		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
+			totals.events[i] += stats->events[i];
+		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
+			totals.bytes[i] += stats->bytes[i];
+#ifdef CONFIG_NFS_FSCACHE
+		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
+			totals.fscache[i] += stats->fscache[i];
+#endif
+
+		preempt_enable();
+	}
+
+	seq_printf(m, "\n\tevents:\t");
+	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
+		seq_printf(m, "%lu ", totals.events[i]);
+	seq_printf(m, "\n\tbytes:\t");
+	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
+		seq_printf(m, "%Lu ", totals.bytes[i]);
+#ifdef CONFIG_NFS_FSCACHE
+	if (nfss->options & NFS_OPTION_FSCACHE) {
+		seq_printf(m, "\n\tfsc:\t");
+		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
+			seq_printf(m, "%Lu ", totals.bytes[i]);
+	}
+#endif
+	seq_printf(m, "\n");
+
+	rpc_print_iostats(m, nfss->client);
+
+	return 0;
+}
+
+/*
+ * Begin unmount by attempting to remove all automounted mountpoints we added
+ * in response to xdev traversals and referrals
+ */
+static void nfs_umount_begin(struct super_block *sb)
+{
+	struct nfs_server *server;
+	struct rpc_clnt *rpc;
+
+	server = NFS_SB(sb);
+	/* -EIO all pending I/O */
+	rpc = server->client_acl;
+	if (!IS_ERR(rpc))
+		rpc_killall_tasks(rpc);
+	rpc = server->client;
+	if (!IS_ERR(rpc))
+		rpc_killall_tasks(rpc);
+}
+
+static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(unsigned int version)
+{
+	struct nfs_parsed_mount_data *data;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (data) {
+		data->acregmin		= NFS_DEF_ACREGMIN;
+		data->acregmax		= NFS_DEF_ACREGMAX;
+		data->acdirmin		= NFS_DEF_ACDIRMIN;
+		data->acdirmax		= NFS_DEF_ACDIRMAX;
+		data->mount_server.port	= NFS_UNSPEC_PORT;
+		data->nfs_server.port	= NFS_UNSPEC_PORT;
+		data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
+		data->auth_flavors[0]	= RPC_AUTH_UNIX;
+		data->auth_flavor_len	= 1;
+		data->version		= version;
+		data->minorversion	= 0;
+		data->net		= current->nsproxy->net_ns;
+		security_init_mnt_opts(&data->lsm_opts);
+	}
+	return data;
+}
+
+static void nfs_free_parsed_mount_data(struct nfs_parsed_mount_data *data)
+{
+	if (data) {
+		kfree(data->client_address);
+		kfree(data->mount_server.hostname);
+		kfree(data->nfs_server.export_path);
+		kfree(data->nfs_server.hostname);
+		kfree(data->fscache_uniq);
+		security_free_mnt_opts(&data->lsm_opts);
+		kfree(data);
+	}
+}
+
+/*
+ * 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;
+}
+
+/*
+ * Select between a default port value and a user-specified port value.
+ * If a zero value is set, then autobind will be used.
+ */
+static void nfs_set_port(struct sockaddr *sap, int *port,
+				 const unsigned short default_port)
+{
+	if (*port == NFS_UNSPEC_PORT)
+		*port = default_port;
+
+	rpc_set_port(sap, *port);
+}
+
+/*
+ * Sanity check the NFS transport protocol.
+ *
+ */
+static void nfs_validate_transport_protocol(struct nfs_parsed_mount_data *mnt)
+{
+	switch (mnt->nfs_server.protocol) {
+	case XPRT_TRANSPORT_UDP:
+	case XPRT_TRANSPORT_TCP:
+	case XPRT_TRANSPORT_RDMA:
+		break;
+	default:
+		mnt->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_parsed_mount_data *mnt)
+{
+	nfs_validate_transport_protocol(mnt);
+
+	if (mnt->mount_server.protocol == XPRT_TRANSPORT_UDP ||
+	    mnt->mount_server.protocol == XPRT_TRANSPORT_TCP)
+			return;
+	switch (mnt->nfs_server.protocol) {
+	case XPRT_TRANSPORT_UDP:
+		mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
+		break;
+	case XPRT_TRANSPORT_TCP:
+	case XPRT_TRANSPORT_RDMA:
+		mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
+	}
+}
+
+/*
+ * Parse the value of the 'sec=' option.
+ */
+static int nfs_parse_security_flavors(char *value,
+				      struct nfs_parsed_mount_data *mnt)
+{
+	substring_t args[MAX_OPT_ARGS];
+
+	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
+
+	switch (match_token(value, nfs_secflavor_tokens, args)) {
+	case Opt_sec_none:
+		mnt->auth_flavors[0] = RPC_AUTH_NULL;
+		break;
+	case Opt_sec_sys:
+		mnt->auth_flavors[0] = RPC_AUTH_UNIX;
+		break;
+	case Opt_sec_krb5:
+		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
+		break;
+	case Opt_sec_krb5i:
+		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
+		break;
+	case Opt_sec_krb5p:
+		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
+		break;
+	case Opt_sec_lkey:
+		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
+		break;
+	case Opt_sec_lkeyi:
+		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
+		break;
+	case Opt_sec_lkeyp:
+		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
+		break;
+	case Opt_sec_spkm:
+		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
+		break;
+	case Opt_sec_spkmi:
+		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
+		break;
+	case Opt_sec_spkmp:
+		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
+		break;
+	default:
+		return 0;
+	}
+
+	mnt->flags |= NFS_MOUNT_SECFLAVOUR;
+	mnt->auth_flavor_len = 1;
+	return 1;
+}
+
+static int nfs_parse_version_string(char *string,
+		struct nfs_parsed_mount_data *mnt,
+		substring_t *args)
+{
+	mnt->flags &= ~NFS_MOUNT_VER3;
+	switch (match_token(string, nfs_vers_tokens, args)) {
+	case Opt_vers_2:
+		mnt->version = 2;
+		break;
+	case Opt_vers_3:
+		mnt->flags |= NFS_MOUNT_VER3;
+		mnt->version = 3;
+		break;
+	case Opt_vers_4:
+		/* Backward compatibility option. In future,
+		 * the mount program should always supply
+		 * a NFSv4 minor version number.
+		 */
+		mnt->version = 4;
+		break;
+	case Opt_vers_4_0:
+		mnt->version = 4;
+		mnt->minorversion = 0;
+		break;
+	case Opt_vers_4_1:
+		mnt->version = 4;
+		mnt->minorversion = 1;
+		break;
+	default:
+		return 0;
+	}
+	return 1;
+}
+
+static int nfs_get_option_str(substring_t args[], char **option)
+{
+	kfree(*option);
+	*option = match_strdup(args);
+	return !*option;
+}
+
+static int nfs_get_option_ul(substring_t args[], unsigned long *option)
+{
+	int rc;
+	char *string;
+
+	string = match_strdup(args);
+	if (string == NULL)
+		return -ENOMEM;
+	rc = strict_strtoul(string, 10, option);
+	kfree(string);
+
+	return rc;
+}
+
+/*
+ * Error-check and convert a string of mount options from user space into
+ * a data structure.  The whole mount string is processed; bad options are
+ * skipped as they are encountered.  If there were no errors, return 1;
+ * otherwise return 0 (zero).
+ */
+static int nfs_parse_mount_options(char *raw,
+				   struct nfs_parsed_mount_data *mnt)
+{
+	char *p, *string, *secdata;
+	int rc, sloppy = 0, invalid_option = 0;
+	unsigned short protofamily = AF_UNSPEC;
+	unsigned short mountfamily = AF_UNSPEC;
+
+	if (!raw) {
+		dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
+		return 1;
+	}
+	dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
+
+	secdata = alloc_secdata();
+	if (!secdata)
+		goto out_nomem;
+
+	rc = security_sb_copy_data(raw, secdata);
+	if (rc)
+		goto out_security_failure;
+
+	rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
+	if (rc)
+		goto out_security_failure;
+
+	free_secdata(secdata);
+
+	while ((p = strsep(&raw, ",")) != NULL) {
+		substring_t args[MAX_OPT_ARGS];
+		unsigned long option;
+		int token;
+
+		if (!*p)
+			continue;
+
+		dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
+
+		token = match_token(p, nfs_mount_option_tokens, args);
+		switch (token) {
+
+		/*
+		 * boolean options:  foo/nofoo
+		 */
+		case Opt_soft:
+			mnt->flags |= NFS_MOUNT_SOFT;
+			break;
+		case Opt_hard:
+			mnt->flags &= ~NFS_MOUNT_SOFT;
+			break;
+		case Opt_posix:
+			mnt->flags |= NFS_MOUNT_POSIX;
+			break;
+		case Opt_noposix:
+			mnt->flags &= ~NFS_MOUNT_POSIX;
+			break;
+		case Opt_cto:
+			mnt->flags &= ~NFS_MOUNT_NOCTO;
+			break;
+		case Opt_nocto:
+			mnt->flags |= NFS_MOUNT_NOCTO;
+			break;
+		case Opt_ac:
+			mnt->flags &= ~NFS_MOUNT_NOAC;
+			break;
+		case Opt_noac:
+			mnt->flags |= NFS_MOUNT_NOAC;
+			break;
+		case Opt_lock:
+			mnt->flags &= ~NFS_MOUNT_NONLM;
+			mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
+					NFS_MOUNT_LOCAL_FCNTL);
+			break;
+		case Opt_nolock:
+			mnt->flags |= NFS_MOUNT_NONLM;
+			mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
+				       NFS_MOUNT_LOCAL_FCNTL);
+			break;
+		case Opt_udp:
+			mnt->flags &= ~NFS_MOUNT_TCP;
+			mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
+			break;
+		case Opt_tcp:
+			mnt->flags |= NFS_MOUNT_TCP;
+			mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
+			break;
+		case Opt_rdma:
+			mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
+			mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
+			xprt_load_transport(p);
+			break;
+		case Opt_acl:
+			mnt->flags &= ~NFS_MOUNT_NOACL;
+			break;
+		case Opt_noacl:
+			mnt->flags |= NFS_MOUNT_NOACL;
+			break;
+		case Opt_rdirplus:
+			mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
+			break;
+		case Opt_nordirplus:
+			mnt->flags |= NFS_MOUNT_NORDIRPLUS;
+			break;
+		case Opt_sharecache:
+			mnt->flags &= ~NFS_MOUNT_UNSHARED;
+			break;
+		case Opt_nosharecache:
+			mnt->flags |= NFS_MOUNT_UNSHARED;
+			break;
+		case Opt_resvport:
+			mnt->flags &= ~NFS_MOUNT_NORESVPORT;
+			break;
+		case Opt_noresvport:
+			mnt->flags |= NFS_MOUNT_NORESVPORT;
+			break;
+		case Opt_fscache:
+			mnt->options |= NFS_OPTION_FSCACHE;
+			kfree(mnt->fscache_uniq);
+			mnt->fscache_uniq = NULL;
+			break;
+		case Opt_nofscache:
+			mnt->options &= ~NFS_OPTION_FSCACHE;
+			kfree(mnt->fscache_uniq);
+			mnt->fscache_uniq = NULL;
+			break;
+
+		/*
+		 * options that take numeric values
+		 */
+		case Opt_port:
+			if (nfs_get_option_ul(args, &option) ||
+			    option > USHRT_MAX)
+				goto out_invalid_value;
+			mnt->nfs_server.port = option;
+			break;
+		case Opt_rsize:
+			if (nfs_get_option_ul(args, &option))
+				goto out_invalid_value;
+			mnt->rsize = option;
+			break;
+		case Opt_wsize:
+			if (nfs_get_option_ul(args, &option))
+				goto out_invalid_value;
+			mnt->wsize = option;
+			break;
+		case Opt_bsize:
+			if (nfs_get_option_ul(args, &option))
+				goto out_invalid_value;
+			mnt->bsize = option;
+			break;
+		case Opt_timeo:
+			if (nfs_get_option_ul(args, &option) || option == 0)
+				goto out_invalid_value;
+			mnt->timeo = option;
+			break;
+		case Opt_retrans:
+			if (nfs_get_option_ul(args, &option) || option == 0)
+				goto out_invalid_value;
+			mnt->retrans = option;
+			break;
+		case Opt_acregmin:
+			if (nfs_get_option_ul(args, &option))
+				goto out_invalid_value;
+			mnt->acregmin = option;
+			break;
+		case Opt_acregmax:
+			if (nfs_get_option_ul(args, &option))
+				goto out_invalid_value;
+			mnt->acregmax = option;
+			break;
+		case Opt_acdirmin:
+			if (nfs_get_option_ul(args, &option))
+				goto out_invalid_value;
+			mnt->acdirmin = option;
+			break;
+		case Opt_acdirmax:
+			if (nfs_get_option_ul(args, &option))
+				goto out_invalid_value;
+			mnt->acdirmax = option;
+			break;
+		case Opt_actimeo:
+			if (nfs_get_option_ul(args, &option))
+				goto out_invalid_value;
+			mnt->acregmin = mnt->acregmax =
+			mnt->acdirmin = mnt->acdirmax = option;
+			break;
+		case Opt_namelen:
+			if (nfs_get_option_ul(args, &option))
+				goto out_invalid_value;
+			mnt->namlen = option;
+			break;
+		case Opt_mountport:
+			if (nfs_get_option_ul(args, &option) ||
+			    option > USHRT_MAX)
+				goto out_invalid_value;
+			mnt->mount_server.port = option;
+			break;
+		case Opt_mountvers:
+			if (nfs_get_option_ul(args, &option) ||
+			    option < NFS_MNT_VERSION ||
+			    option > NFS_MNT3_VERSION)
+				goto out_invalid_value;
+			mnt->mount_server.version = option;
+			break;
+		case Opt_minorversion:
+			if (nfs_get_option_ul(args, &option))
+				goto out_invalid_value;
+			if (option > NFS4_MAX_MINOR_VERSION)
+				goto out_invalid_value;
+			mnt->minorversion = option;
+			break;
+
+		/*
+		 * options that take text values
+		 */
+		case Opt_nfsvers:
+			string = match_strdup(args);
+			if (string == NULL)
+				goto out_nomem;
+			rc = nfs_parse_version_string(string, mnt, args);
+			kfree(string);
+			if (!rc)
+				goto out_invalid_value;
+			break;
+		case Opt_sec:
+			string = match_strdup(args);
+			if (string == NULL)
+				goto out_nomem;
+			rc = nfs_parse_security_flavors(string, mnt);
+			kfree(string);
+			if (!rc) {
+				dfprintk(MOUNT, "NFS:   unrecognized "
+						"security flavor\n");
+				return 0;
+			}
+			break;
+		case Opt_proto:
+			string = match_strdup(args);
+			if (string == NULL)
+				goto out_nomem;
+			token = match_token(string,
+					    nfs_xprt_protocol_tokens, args);
+
+			protofamily = AF_INET;
+			switch (token) {
+			case Opt_xprt_udp6:
+				protofamily = AF_INET6;
+			case Opt_xprt_udp:
+				mnt->flags &= ~NFS_MOUNT_TCP;
+				mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
+				break;
+			case Opt_xprt_tcp6:
+				protofamily = AF_INET6;
+			case Opt_xprt_tcp:
+				mnt->flags |= NFS_MOUNT_TCP;
+				mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
+				break;
+			case Opt_xprt_rdma:
+				/* vector side protocols to TCP */
+				mnt->flags |= NFS_MOUNT_TCP;
+				mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
+				xprt_load_transport(string);
+				break;
+			default:
+				dfprintk(MOUNT, "NFS:   unrecognized "
+						"transport protocol\n");
+				kfree(string);
+				return 0;
+			}
+			kfree(string);
+			break;
+		case Opt_mountproto:
+			string = match_strdup(args);
+			if (string == NULL)
+				goto out_nomem;
+			token = match_token(string,
+					    nfs_xprt_protocol_tokens, args);
+			kfree(string);
+
+			mountfamily = AF_INET;
+			switch (token) {
+			case Opt_xprt_udp6:
+				mountfamily = AF_INET6;
+			case Opt_xprt_udp:
+				mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
+				break;
+			case Opt_xprt_tcp6:
+				mountfamily = AF_INET6;
+			case Opt_xprt_tcp:
+				mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
+				break;
+			case Opt_xprt_rdma: /* not used for side protocols */
+			default:
+				dfprintk(MOUNT, "NFS:   unrecognized "
+						"transport protocol\n");
+				return 0;
+			}
+			break;
+		case Opt_addr:
+			string = match_strdup(args);
+			if (string == NULL)
+				goto out_nomem;
+			mnt->nfs_server.addrlen =
+				rpc_pton(mnt->net, string, strlen(string),
+					(struct sockaddr *)
+					&mnt->nfs_server.address,
+					sizeof(mnt->nfs_server.address));
+			kfree(string);
+			if (mnt->nfs_server.addrlen == 0)
+				goto out_invalid_address;
+			break;
+		case Opt_clientaddr:
+			if (nfs_get_option_str(args, &mnt->client_address))
+				goto out_nomem;
+			break;
+		case Opt_mounthost:
+			if (nfs_get_option_str(args,
+					       &mnt->mount_server.hostname))
+				goto out_nomem;
+			break;
+		case Opt_mountaddr:
+			string = match_strdup(args);
+			if (string == NULL)
+				goto out_nomem;
+			mnt->mount_server.addrlen =
+				rpc_pton(mnt->net, string, strlen(string),
+					(struct sockaddr *)
+					&mnt->mount_server.address,
+					sizeof(mnt->mount_server.address));
+			kfree(string);
+			if (mnt->mount_server.addrlen == 0)
+				goto out_invalid_address;
+			break;
+		case Opt_lookupcache:
+			string = match_strdup(args);
+			if (string == NULL)
+				goto out_nomem;
+			token = match_token(string,
+					nfs_lookupcache_tokens, args);
+			kfree(string);
+			switch (token) {
+				case Opt_lookupcache_all:
+					mnt->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
+					break;
+				case Opt_lookupcache_positive:
+					mnt->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
+					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
+					break;
+				case Opt_lookupcache_none:
+					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
+					break;
+				default:
+					dfprintk(MOUNT, "NFS:   invalid "
+							"lookupcache argument\n");
+					return 0;
+			};
+			break;
+		case Opt_fscache_uniq:
+			if (nfs_get_option_str(args, &mnt->fscache_uniq))
+				goto out_nomem;
+			mnt->options |= NFS_OPTION_FSCACHE;
+			break;
+		case Opt_local_lock:
+			string = match_strdup(args);
+			if (string == NULL)
+				goto out_nomem;
+			token = match_token(string, nfs_local_lock_tokens,
+					args);
+			kfree(string);
+			switch (token) {
+			case Opt_local_lock_all:
+				mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
+					       NFS_MOUNT_LOCAL_FCNTL);
+				break;
+			case Opt_local_lock_flock:
+				mnt->flags |= NFS_MOUNT_LOCAL_FLOCK;
+				break;
+			case Opt_local_lock_posix:
+				mnt->flags |= NFS_MOUNT_LOCAL_FCNTL;
+				break;
+			case Opt_local_lock_none:
+				mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
+						NFS_MOUNT_LOCAL_FCNTL);
+				break;
+			default:
+				dfprintk(MOUNT, "NFS:	invalid	"
+						"local_lock argument\n");
+				return 0;
+			};
+			break;
+
+		/*
+		 * Special options
+		 */
+		case Opt_sloppy:
+			sloppy = 1;
+			dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
+			break;
+		case Opt_userspace:
+		case Opt_deprecated:
+			dfprintk(MOUNT, "NFS:   ignoring mount option "
+					"'%s'\n", p);
+			break;
+
+		default:
+			invalid_option = 1;
+			dfprintk(MOUNT, "NFS:   unrecognized mount option "
+					"'%s'\n", p);
+		}
+	}
+
+	if (!sloppy && invalid_option)
+		return 0;
+
+	if (mnt->minorversion && mnt->version != 4)
+		goto out_minorversion_mismatch;
+
+	/*
+	 * verify that any proto=/mountproto= options match the address
+	 * familiies in the addr=/mountaddr= options.
+	 */
+	if (protofamily != AF_UNSPEC &&
+	    protofamily != mnt->nfs_server.address.ss_family)
+		goto out_proto_mismatch;
+
+	if (mountfamily != AF_UNSPEC) {
+		if (mnt->mount_server.addrlen) {
+			if (mountfamily != mnt->mount_server.address.ss_family)
+				goto out_mountproto_mismatch;
+		} else {
+			if (mountfamily != mnt->nfs_server.address.ss_family)
+				goto out_mountproto_mismatch;
+		}
+	}
+
+	return 1;
+
+out_mountproto_mismatch:
+	printk(KERN_INFO "NFS: mount server address does not match mountproto= "
+			 "option\n");
+	return 0;
+out_proto_mismatch:
+	printk(KERN_INFO "NFS: server address does not match proto= option\n");
+	return 0;
+out_invalid_address:
+	printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
+	return 0;
+out_invalid_value:
+	printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
+	return 0;
+out_minorversion_mismatch:
+	printk(KERN_INFO "NFS: mount option vers=%u does not support "
+			 "minorversion=%u\n", mnt->version, mnt->minorversion);
+	return 0;
+out_nomem:
+	printk(KERN_INFO "NFS: not enough memory to parse option\n");
+	return 0;
+out_security_failure:
+	free_secdata(secdata);
+	printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
+	return 0;
+}
+
+/*
+ * Match the requested auth flavors with the list returned by
+ * the server.  Returns zero and sets the mount's authentication
+ * flavor on success; returns -EACCES if server does not support
+ * the requested flavor.
+ */
+static int nfs_walk_authlist(struct nfs_parsed_mount_data *args,
+			     struct nfs_mount_request *request)
+{
+	unsigned int i, j, server_authlist_len = *(request->auth_flav_len);
+
+	/*
+	 * Certain releases of Linux's mountd return an empty
+	 * flavor list.  To prevent behavioral regression with
+	 * these servers (ie. rejecting mounts that used to
+	 * succeed), revert to pre-2.6.32 behavior (no checking)
+	 * if the returned flavor list is empty.
+	 */
+	if (server_authlist_len == 0)
+		return 0;
+
+	/*
+	 * We avoid sophisticated negotiating here, as there are
+	 * plenty of cases where we can get it wrong, providing
+	 * either too little or too much security.
+	 *
+	 * RFC 2623, section 2.7 suggests we SHOULD prefer the
+	 * flavor listed first.  However, some servers list
+	 * AUTH_NULL first.  Our caller plants AUTH_SYS, the
+	 * preferred default, in args->auth_flavors[0] if user
+	 * didn't specify sec= mount option.
+	 */
+	for (i = 0; i < args->auth_flavor_len; i++)
+		for (j = 0; j < server_authlist_len; j++)
+			if (args->auth_flavors[i] == request->auth_flavs[j]) {
+				dfprintk(MOUNT, "NFS: using auth flavor %d\n",
+					request->auth_flavs[j]);
+				args->auth_flavors[0] = request->auth_flavs[j];
+				return 0;
+			}
+
+	dfprintk(MOUNT, "NFS: server does not support requested auth flavor\n");
+	nfs_umount(request);
+	return -EACCES;
+}
+
+/*
+ * Use the remote server's MOUNT service to request the NFS file handle
+ * corresponding to the provided path.
+ */
+static int nfs_try_mount(struct nfs_parsed_mount_data *args,
+			 struct nfs_fh *root_fh)
+{
+	rpc_authflavor_t server_authlist[NFS_MAX_SECFLAVORS];
+	unsigned int server_authlist_len = ARRAY_SIZE(server_authlist);
+	struct nfs_mount_request request = {
+		.sap		= (struct sockaddr *)
+						&args->mount_server.address,
+		.dirpath	= args->nfs_server.export_path,
+		.protocol	= args->mount_server.protocol,
+		.fh		= root_fh,
+		.noresvport	= args->flags & NFS_MOUNT_NORESVPORT,
+		.auth_flav_len	= &server_authlist_len,
+		.auth_flavs	= server_authlist,
+		.net		= args->net,
+	};
+	int status;
+
+	if (args->mount_server.version == 0) {
+		switch (args->version) {
+			default:
+				args->mount_server.version = NFS_MNT3_VERSION;
+				break;
+			case 2:
+				args->mount_server.version = NFS_MNT_VERSION;
+		}
+	}
+	request.version = args->mount_server.version;
+
+	if (args->mount_server.hostname)
+		request.hostname = args->mount_server.hostname;
+	else
+		request.hostname = args->nfs_server.hostname;
+
+	/*
+	 * Construct the mount server's address.
+	 */
+	if (args->mount_server.address.ss_family == AF_UNSPEC) {
+		memcpy(request.sap, &args->nfs_server.address,
+		       args->nfs_server.addrlen);
+		args->mount_server.addrlen = args->nfs_server.addrlen;
+	}
+	request.salen = args->mount_server.addrlen;
+	nfs_set_port(request.sap, &args->mount_server.port, 0);
+
+	/*
+	 * Now ask the mount server to map our export path
+	 * to a file handle.
+	 */
+	status = nfs_mount(&request);
+	if (status != 0) {
+		dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
+				request.hostname, status);
+		return status;
+	}
+
+	/*
+	 * MNTv1 (NFSv2) does not support auth flavor negotiation.
+	 */
+	if (args->mount_server.version != NFS_MNT3_VERSION)
+		return 0;
+	return nfs_walk_authlist(args, &request);
+}
+
+/*
+ * Split "dev_name" 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_devname(const char *dev_name,
+			     char **hostname, size_t maxnamlen,
+			     char **export_path, size_t maxpathlen)
+{
+	size_t len;
+	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 {
+		char *comma;
+
+		end = strchr(dev_name, ':');
+		if (end == NULL)
+			goto out_bad_devname;
+		len = end - dev_name;
+
+		/* kill possible hostname list: not supported */
+		comma = strchr(dev_name, ',');
+		if (comma != NULL && comma < end)
+			*comma = 0;
+	}
+
+	if (len > maxnamlen)
+		goto out_hostname;
+
+	/* N.B. caller will free nfs_server.hostname in all cases */
+	*hostname = kstrndup(dev_name, len, GFP_KERNEL);
+	if (*hostname == NULL)
+		goto out_nomem;
+	len = strlen(++end);
+	if (len > maxpathlen)
+		goto out_path;
+	*export_path = kstrndup(end, len, GFP_KERNEL);
+	if (!*export_path)
+		goto out_nomem;
+
+	dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
+	return 0;
+
+out_bad_devname:
+	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
+	return -EINVAL;
+
+out_nomem:
+	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
+	return -ENOMEM;
+
+out_hostname:
+	dfprintk(MOUNT, "NFS: server hostname too long\n");
+	return -ENAMETOOLONG;
+
+out_path:
+	dfprintk(MOUNT, "NFS: export pathname too long\n");
+	return -ENAMETOOLONG;
+}
+
+/*
+ * Validate the 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 nfs_validate_mount_data(void *options,
+				   struct nfs_parsed_mount_data *args,
+				   struct nfs_fh *mntfh,
+				   const char *dev_name)
+{
+	struct nfs_mount_data *data = (struct nfs_mount_data *)options;
+	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
+
+	if (data == NULL)
+		goto out_no_data;
+
+	switch (data->version) {
+	case 1:
+		data->namlen = 0;
+	case 2:
+		data->bsize = 0;
+	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);
+	case 4:
+		if (data->flags & NFS_MOUNT_SECFLAVOUR)
+			goto out_no_sec;
+	case 5:
+		memset(data->context, 0, sizeof(data->context));
+	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;
+			args->version = 3;
+		} else {
+			mntfh->size = NFS2_FHSIZE;
+			args->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_parsed_mount_data, which nfs_fill_super
+		 * can deal with.
+		 */
+		args->flags		= data->flags & NFS_MOUNT_FLAGMASK;
+		args->flags		|= NFS_MOUNT_LEGACY_INTERFACE;
+		args->rsize		= data->rsize;
+		args->wsize		= data->wsize;
+		args->timeo		= data->timeo;
+		args->retrans		= data->retrans;
+		args->acregmin		= data->acregmin;
+		args->acregmax		= data->acregmax;
+		args->acdirmin		= data->acdirmin;
+		args->acdirmax		= data->acdirmax;
+
+		memcpy(sap, &data->addr, sizeof(data->addr));
+		args->nfs_server.addrlen = sizeof(data->addr);
+		args->nfs_server.port = ntohs(data->addr.sin_port);
+		if (!nfs_verify_server_address(sap))
+			goto out_no_address;
+
+		if (!(data->flags & NFS_MOUNT_TCP))
+			args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
+		/* N.B. caller will free nfs_server.hostname in all cases */
+		args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
+		args->namlen		= data->namlen;
+		args->bsize		= data->bsize;
+
+		if (data->flags & NFS_MOUNT_SECFLAVOUR)
+			args->auth_flavors[0] = data->pseudoflavor;
+		if (!args->nfs_server.hostname)
+			goto out_nomem;
+
+		if (!(data->flags & NFS_MOUNT_NONLM))
+			args->flags &= ~(NFS_MOUNT_LOCAL_FLOCK|
+					 NFS_MOUNT_LOCAL_FCNTL);
+		else
+			args->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 rc;
+			char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
+			if (!opts_str)
+				return -ENOMEM;
+			strcpy(opts_str, "context=");
+			data->context[NFS_MAX_CONTEXT_LEN] = '\0';
+			strcat(opts_str, &data->context[0]);
+			rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
+			kfree(opts_str);
+			if (rc)
+				return rc;
+#else
+			return -EINVAL;
+#endif
+		}
+
+		break;
+	default: {
+		int status;
+
+		if (nfs_parse_mount_options((char *)options, args) == 0)
+			return -EINVAL;
+
+		if (!nfs_verify_server_address(sap))
+			goto out_no_address;
+
+		if (args->version == 4)
+#ifdef CONFIG_NFS_V4
+			return nfs4_validate_text_mount_data(options,
+							     args, dev_name);
+#else
+			goto out_v4_not_compiled;
+#endif
+
+		nfs_set_port(sap, &args->nfs_server.port, 0);
+
+		nfs_set_mount_transport_protocol(args);
+
+		status = nfs_parse_devname(dev_name,
+					   &args->nfs_server.hostname,
+					   PAGE_SIZE,
+					   &args->nfs_server.export_path,
+					   NFS_MAXPATHLEN);
+		if (!status)
+			status = nfs_try_mount(args, mntfh);
+
+		kfree(args->nfs_server.export_path);
+		args->nfs_server.export_path = NULL;
+
+		if (status)
+			return status;
+
+		break;
+		}
+	}
+
+#ifndef CONFIG_NFS_V3
+	if (args->version == 3)
+		goto out_v3_not_compiled;
+#endif /* !CONFIG_NFS_V3 */
+
+	return 0;
+
+out_no_data:
+	dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
+	return -EINVAL;
+
+out_no_v3:
+	dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
+		 data->version);
+	return -EINVAL;
+
+out_no_sec:
+	dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
+	return -EINVAL;
+
+#ifndef CONFIG_NFS_V3
+out_v3_not_compiled:
+	dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
+	return -EPROTONOSUPPORT;
+#endif /* !CONFIG_NFS_V3 */
+
+#ifndef CONFIG_NFS_V4
+out_v4_not_compiled:
+	dfprintk(MOUNT, "NFS: NFSv4 is not compiled into kernel\n");
+	return -EPROTONOSUPPORT;
+#endif /* !CONFIG_NFS_V4 */
+
+out_nomem:
+	dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
+	return -ENOMEM;
+
+out_no_address:
+	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
+	return -EINVAL;
+
+out_invalid_fh:
+	dfprintk(MOUNT, "NFS: invalid root filehandle\n");
+	return -EINVAL;
+}
+
+static int
+nfs_compare_remount_data(struct nfs_server *nfss,
+			 struct nfs_parsed_mount_data *data)
+{
+	if (data->flags != nfss->flags ||
+	    data->rsize != nfss->rsize ||
+	    data->wsize != nfss->wsize ||
+	    data->retrans != nfss->client->cl_timeout->to_retries ||
+	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
+	    data->acregmin != nfss->acregmin / HZ ||
+	    data->acregmax != nfss->acregmax / HZ ||
+	    data->acdirmin != nfss->acdirmin / HZ ||
+	    data->acdirmax != nfss->acdirmax / HZ ||
+	    data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
+	    data->nfs_server.port != nfss->port ||
+	    data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
+	    !rpc_cmp_addr((struct sockaddr *)&data->nfs_server.address,
+			  (struct sockaddr *)&nfss->nfs_client->cl_addr))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int
+nfs_remount(struct super_block *sb, int *flags, char *raw_data)
+{
+	int error;
+	struct nfs_server *nfss = sb->s_fs_info;
+	struct nfs_parsed_mount_data *data;
+	struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
+	struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
+	u32 nfsvers = nfss->nfs_client->rpc_ops->version;
+
+	/*
+	 * Userspace mount programs that send binary options generally send
+	 * them populated with default values. We have no way to know which
+	 * ones were explicitly specified. Fall back to legacy behavior and
+	 * just return success.
+	 */
+	if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
+	    (nfsvers <= 3 && (!options || (options->version >= 1 &&
+					   options->version <= 6))))
+		return 0;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (data == NULL)
+		return -ENOMEM;
+
+	/* fill out struct with values from existing mount */
+	data->flags = nfss->flags;
+	data->rsize = nfss->rsize;
+	data->wsize = nfss->wsize;
+	data->retrans = nfss->client->cl_timeout->to_retries;
+	data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
+	data->acregmin = nfss->acregmin / HZ;
+	data->acregmax = nfss->acregmax / HZ;
+	data->acdirmin = nfss->acdirmin / HZ;
+	data->acdirmax = nfss->acdirmax / HZ;
+	data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
+	data->nfs_server.port = nfss->port;
+	data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
+	memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
+		data->nfs_server.addrlen);
+
+	/* overwrite those values with any that were specified */
+	error = nfs_parse_mount_options((char *)options, data);
+	if (error < 0)
+		goto out;
+
+	/*
+	 * noac is a special case. It implies -o sync, but that's not
+	 * necessarily reflected in the mtab options. do_remount_sb
+	 * will clear MS_SYNCHRONOUS if -o sync wasn't specified in the
+	 * remount options, so we have to explicitly reset it.
+	 */
+	if (data->flags & NFS_MOUNT_NOAC)
+		*flags |= MS_SYNCHRONOUS;
+
+	/* compare new mount options with old ones */
+	error = nfs_compare_remount_data(nfss, data);
+out:
+	kfree(data);
+	return error;
+}
+
+/*
+ * Initialise the common bits of the superblock
+ */
+static inline void nfs_initialise_sb(struct super_block *sb)
+{
+	struct nfs_server *server = NFS_SB(sb);
+
+	sb->s_magic = NFS_SUPER_MAGIC;
+
+	/* We probably want something more informative here */
+	snprintf(sb->s_id, sizeof(sb->s_id),
+		 "%u:%u", MAJOR(sb->s_dev), MINOR(sb->s_dev));
+
+	if (sb->s_blocksize == 0)
+		sb->s_blocksize = nfs_block_bits(server->wsize,
+						 &sb->s_blocksize_bits);
+
+	sb->s_bdi = &server->backing_dev_info;
+
+	nfs_super_set_maxbytes(sb, server->maxfilesize);
+}
+
+/*
+ * Finish setting up an NFS2/3 superblock
+ */
+static void nfs_fill_super(struct super_block *sb,
+			   struct nfs_parsed_mount_data *data)
+{
+	struct nfs_server *server = NFS_SB(sb);
+
+	sb->s_blocksize_bits = 0;
+	sb->s_blocksize = 0;
+	if (data->bsize)
+		sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
+
+	if (server->nfs_client->rpc_ops->version == 3) {
+		/* The VFS shouldn't apply the umask to mode bits. We will do
+		 * so ourselves when necessary.
+		 */
+		sb->s_flags |= MS_POSIXACL;
+		sb->s_time_gran = 1;
+	}
+
+	sb->s_op = &nfs_sops;
+ 	nfs_initialise_sb(sb);
+}
+
+/*
+ * Finish setting up a cloned NFS2/3 superblock
+ */
+static void nfs_clone_super(struct super_block *sb,
+			    const struct super_block *old_sb)
+{
+	struct nfs_server *server = NFS_SB(sb);
+
+	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
+	sb->s_blocksize = old_sb->s_blocksize;
+	sb->s_maxbytes = old_sb->s_maxbytes;
+
+	if (server->nfs_client->rpc_ops->version == 3) {
+		/* The VFS shouldn't apply the umask to mode bits. We will do
+		 * so ourselves when necessary.
+		 */
+		sb->s_flags |= MS_POSIXACL;
+		sb->s_time_gran = 1;
+	}
+
+	sb->s_op = old_sb->s_op;
+ 	nfs_initialise_sb(sb);
+}
+
+static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
+{
+	const struct nfs_server *a = s->s_fs_info;
+	const struct rpc_clnt *clnt_a = a->client;
+	const struct rpc_clnt *clnt_b = b->client;
+
+	if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
+		goto Ebusy;
+	if (a->nfs_client != b->nfs_client)
+		goto Ebusy;
+	if (a->flags != b->flags)
+		goto Ebusy;
+	if (a->wsize != b->wsize)
+		goto Ebusy;
+	if (a->rsize != b->rsize)
+		goto Ebusy;
+	if (a->acregmin != b->acregmin)
+		goto Ebusy;
+	if (a->acregmax != b->acregmax)
+		goto Ebusy;
+	if (a->acdirmin != b->acdirmin)
+		goto Ebusy;
+	if (a->acdirmax != b->acdirmax)
+		goto Ebusy;
+	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
+		goto Ebusy;
+	return 1;
+Ebusy:
+	return 0;
+}
+
+struct nfs_sb_mountdata {
+	struct nfs_server *server;
+	int mntflags;
+};
+
+static int nfs_set_super(struct super_block *s, void *data)
+{
+	struct nfs_sb_mountdata *sb_mntdata = data;
+	struct nfs_server *server = sb_mntdata->server;
+	int ret;
+
+	s->s_flags = sb_mntdata->mntflags;
+	s->s_fs_info = server;
+	s->s_d_op = server->nfs_client->rpc_ops->dentry_ops;
+	ret = set_anon_super(s, server);
+	if (ret == 0)
+		server->s_dev = s->s_dev;
+	return ret;
+}
+
+static int nfs_compare_super_address(struct nfs_server *server1,
+				     struct nfs_server *server2)
+{
+	struct sockaddr *sap1, *sap2;
+
+	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
+	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
+
+	if (sap1->sa_family != sap2->sa_family)
+		return 0;
+
+	switch (sap1->sa_family) {
+	case AF_INET: {
+		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
+		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
+		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
+			return 0;
+		if (sin1->sin_port != sin2->sin_port)
+			return 0;
+		break;
+	}
+	case AF_INET6: {
+		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
+		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
+		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
+			return 0;
+		if (sin1->sin6_port != sin2->sin6_port)
+			return 0;
+		break;
+	}
+	default:
+		return 0;
+	}
+
+	return 1;
+}
+
+static int nfs_compare_super(struct super_block *sb, void *data)
+{
+	struct nfs_sb_mountdata *sb_mntdata = data;
+	struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
+	int mntflags = sb_mntdata->mntflags;
+
+	if (!nfs_compare_super_address(old, server))
+		return 0;
+	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
+	if (old->flags & NFS_MOUNT_UNSHARED)
+		return 0;
+	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
+		return 0;
+	return nfs_compare_mount_options(sb, server, mntflags);
+}
+
+static int nfs_bdi_register(struct nfs_server *server)
+{
+	return bdi_register_dev(&server->backing_dev_info, server->s_dev);
+}
+
+static struct dentry *nfs_fs_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *raw_data)
+{
+	struct nfs_server *server = NULL;
+	struct super_block *s;
+	struct nfs_parsed_mount_data *data;
+	struct nfs_fh *mntfh;
+	struct dentry *mntroot = ERR_PTR(-ENOMEM);
+	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
+	struct nfs_sb_mountdata sb_mntdata = {
+		.mntflags = flags,
+	};
+	int error;
+
+	data = nfs_alloc_parsed_mount_data(NFS_DEFAULT_VERSION);
+	mntfh = nfs_alloc_fhandle();
+	if (data == NULL || mntfh == NULL)
+		goto out;
+
+	/* Validate the mount data */
+	error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
+	if (error < 0) {
+		mntroot = ERR_PTR(error);
+		goto out;
+	}
+
+#ifdef CONFIG_NFS_V4
+	if (data->version == 4) {
+		mntroot = nfs4_try_mount(flags, dev_name, data);
+		goto out;
+	}
+#endif	/* CONFIG_NFS_V4 */
+
+	/* Get a volume representation */
+	server = nfs_create_server(data, mntfh);
+	if (IS_ERR(server)) {
+		mntroot = ERR_CAST(server);
+		goto out;
+	}
+	sb_mntdata.server = server;
+
+	if (server->flags & NFS_MOUNT_UNSHARED)
+		compare_super = NULL;
+
+	/* -o noac implies -o sync */
+	if (server->flags & NFS_MOUNT_NOAC)
+		sb_mntdata.mntflags |= MS_SYNCHRONOUS;
+
+	/* Get a superblock - note that we may end up sharing one that already exists */
+	s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
+	if (IS_ERR(s)) {
+		mntroot = ERR_CAST(s);
+		goto out_err_nosb;
+	}
+
+	if (s->s_fs_info != server) {
+		nfs_free_server(server);
+		server = NULL;
+	} else {
+		error = nfs_bdi_register(server);
+		if (error) {
+			mntroot = ERR_PTR(error);
+			goto error_splat_bdi;
+		}
+	}
+
+	if (!s->s_root) {
+		/* initial superblock/root creation */
+		nfs_fill_super(s, data);
+		nfs_fscache_get_super_cookie(s, data->fscache_uniq, NULL);
+	}
+
+	mntroot = nfs_get_root(s, mntfh, dev_name);
+	if (IS_ERR(mntroot))
+		goto error_splat_super;
+
+	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
+	if (error)
+		goto error_splat_root;
+
+	s->s_flags |= MS_ACTIVE;
+
+out:
+	nfs_free_parsed_mount_data(data);
+	nfs_free_fhandle(mntfh);
+	return mntroot;
+
+out_err_nosb:
+	nfs_free_server(server);
+	goto out;
+
+error_splat_root:
+	dput(mntroot);
+	mntroot = ERR_PTR(error);
+error_splat_super:
+	if (server && !s->s_root)
+		bdi_unregister(&server->backing_dev_info);
+error_splat_bdi:
+	deactivate_locked_super(s);
+	goto out;
+}
+
+/*
+ * Ensure that we unregister the bdi before kill_anon_super
+ * releases the device name
+ */
+static void nfs_put_super(struct super_block *s)
+{
+	struct nfs_server *server = NFS_SB(s);
+
+	bdi_unregister(&server->backing_dev_info);
+}
+
+/*
+ * Destroy an NFS2/3 superblock
+ */
+static void nfs_kill_super(struct super_block *s)
+{
+	struct nfs_server *server = NFS_SB(s);
+
+	kill_anon_super(s);
+	nfs_fscache_release_super_cookie(s);
+	nfs_free_server(server);
+}
+
+/*
+ * Clone an NFS2/3 server record on xdev traversal (FSID-change)
+ */
+static struct dentry *
+nfs_xdev_mount(struct file_system_type *fs_type, int flags,
+		const char *dev_name, void *raw_data)
+{
+	struct nfs_clone_mount *data = raw_data;
+	struct super_block *s;
+	struct nfs_server *server;
+	struct dentry *mntroot;
+	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
+	struct nfs_sb_mountdata sb_mntdata = {
+		.mntflags = flags,
+	};
+	int error;
+
+	dprintk("--> nfs_xdev_mount()\n");
+
+	/* create a new volume representation */
+	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr, data->authflavor);
+	if (IS_ERR(server)) {
+		error = PTR_ERR(server);
+		goto out_err_noserver;
+	}
+	sb_mntdata.server = server;
+
+	if (server->flags & NFS_MOUNT_UNSHARED)
+		compare_super = NULL;
+
+	/* -o noac implies -o sync */
+	if (server->flags & NFS_MOUNT_NOAC)
+		sb_mntdata.mntflags |= MS_SYNCHRONOUS;
+
+	/* Get a superblock - note that we may end up sharing one that already exists */
+	s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
+	if (IS_ERR(s)) {
+		error = PTR_ERR(s);
+		goto out_err_nosb;
+	}
+
+	if (s->s_fs_info != server) {
+		nfs_free_server(server);
+		server = NULL;
+	} else {
+		error = nfs_bdi_register(server);
+		if (error)
+			goto error_splat_bdi;
+	}
+
+	if (!s->s_root) {
+		/* initial superblock/root creation */
+		nfs_clone_super(s, data->sb);
+		nfs_fscache_get_super_cookie(s, NULL, data);
+	}
+
+	mntroot = nfs_get_root(s, data->fh, dev_name);
+	if (IS_ERR(mntroot)) {
+		error = PTR_ERR(mntroot);
+		goto error_splat_super;
+	}
+	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
+		dput(mntroot);
+		error = -ESTALE;
+		goto error_splat_super;
+	}
+
+	s->s_flags |= MS_ACTIVE;
+
+	/* clone any lsm security options from the parent to the new sb */
+	security_sb_clone_mnt_opts(data->sb, s);
+
+	dprintk("<-- nfs_xdev_mount() = 0\n");
+	return mntroot;
+
+out_err_nosb:
+	nfs_free_server(server);
+out_err_noserver:
+	dprintk("<-- nfs_xdev_mount() = %d [error]\n", error);
+	return ERR_PTR(error);
+
+error_splat_super:
+	if (server && !s->s_root)
+		bdi_unregister(&server->backing_dev_info);
+error_splat_bdi:
+	deactivate_locked_super(s);
+	dprintk("<-- nfs_xdev_mount() = %d [splat]\n", error);
+	return ERR_PTR(error);
+}
+
+#ifdef CONFIG_NFS_V4
+
+/*
+ * Finish setting up a cloned NFS4 superblock
+ */
+static void nfs4_clone_super(struct super_block *sb,
+			    const struct super_block *old_sb)
+{
+	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
+	sb->s_blocksize = old_sb->s_blocksize;
+	sb->s_maxbytes = old_sb->s_maxbytes;
+	sb->s_time_gran = 1;
+	sb->s_op = old_sb->s_op;
+	/*
+	 * The VFS shouldn't apply the umask to mode bits. We will do
+	 * so ourselves when necessary.
+	 */
+	sb->s_flags  |= MS_POSIXACL;
+	sb->s_xattr  = old_sb->s_xattr;
+	nfs_initialise_sb(sb);
+}
+
+/*
+ * Set up an NFS4 superblock
+ */
+static void nfs4_fill_super(struct super_block *sb)
+{
+	sb->s_time_gran = 1;
+	sb->s_op = &nfs4_sops;
+	/*
+	 * The VFS shouldn't apply the umask to mode bits. We will do
+	 * so ourselves when necessary.
+	 */
+	sb->s_flags  |= MS_POSIXACL;
+	sb->s_xattr = nfs4_xattr_handlers;
+	nfs_initialise_sb(sb);
+}
+
+static void nfs4_validate_mount_flags(struct nfs_parsed_mount_data *args)
+{
+	args->flags &= ~(NFS_MOUNT_NONLM|NFS_MOUNT_NOACL|NFS_MOUNT_VER3|
+			 NFS_MOUNT_LOCAL_FLOCK|NFS_MOUNT_LOCAL_FCNTL);
+}
+
+static int nfs4_validate_text_mount_data(void *options,
+					 struct nfs_parsed_mount_data *args,
+					 const char *dev_name)
+{
+	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
+
+	nfs_set_port(sap, &args->nfs_server.port, NFS_PORT);
+
+	nfs_validate_transport_protocol(args);
+
+	nfs4_validate_mount_flags(args);
+
+	if (args->version != 4) {
+		dfprintk(MOUNT,
+			 "NFS4: Illegal mount version\n");
+		return -EINVAL;
+	}
+
+	if (args->auth_flavor_len > 1) {
+		dfprintk(MOUNT,
+			 "NFS4: Too many RPC auth flavours specified\n");
+		return -EINVAL;
+	}
+
+	return nfs_parse_devname(dev_name,
+				   &args->nfs_server.hostname,
+				   NFS4_MAXNAMLEN,
+				   &args->nfs_server.export_path,
+				   NFS4_MAXPATHLEN);
+}
+
+/*
+ * Validate NFSv4 mount options
+ */
+static int nfs4_validate_mount_data(void *options,
+				    struct nfs_parsed_mount_data *args,
+				    const char *dev_name)
+{
+	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
+	struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
+	char *c;
+
+	if (data == NULL)
+		goto out_no_data;
+
+	switch (data->version) {
+	case 1:
+		if (data->host_addrlen > sizeof(args->nfs_server.address))
+			goto out_no_address;
+		if (data->host_addrlen == 0)
+			goto out_no_address;
+		args->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;
+		args->nfs_server.port = ntohs(((struct sockaddr_in *)sap)->sin_port);
+
+		if (data->auth_flavourlen) {
+			if (data->auth_flavourlen > 1)
+				goto out_inval_auth;
+			if (copy_from_user(&args->auth_flavors[0],
+					   data->auth_flavours,
+					   sizeof(args->auth_flavors[0])))
+				return -EFAULT;
+		}
+
+		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
+		if (IS_ERR(c))
+			return PTR_ERR(c);
+		args->nfs_server.hostname = c;
+
+		c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
+		if (IS_ERR(c))
+			return PTR_ERR(c);
+		args->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);
+		args->client_address = c;
+
+		/*
+		 * Translate to nfs_parsed_mount_data, which nfs4_fill_super
+		 * can deal with.
+		 */
+
+		args->flags	= data->flags & NFS4_MOUNT_FLAGMASK;
+		args->rsize	= data->rsize;
+		args->wsize	= data->wsize;
+		args->timeo	= data->timeo;
+		args->retrans	= data->retrans;
+		args->acregmin	= data->acregmin;
+		args->acregmax	= data->acregmax;
+		args->acdirmin	= data->acdirmin;
+		args->acdirmax	= data->acdirmax;
+		args->nfs_server.protocol = data->proto;
+		nfs_validate_transport_protocol(args);
+
+		break;
+	default:
+		if (nfs_parse_mount_options((char *)options, args) == 0)
+			return -EINVAL;
+
+		if (!nfs_verify_server_address(sap))
+			return -EINVAL;
+
+		return nfs4_validate_text_mount_data(options, args, dev_name);
+	}
+
+	return 0;
+
+out_no_data:
+	dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
+	return -EINVAL;
+
+out_inval_auth:
+	dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
+		 data->auth_flavourlen);
+	return -EINVAL;
+
+out_no_address:
+	dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
+	return -EINVAL;
+}
+
+/*
+ * Get the superblock for the NFS4 root partition
+ */
+static struct dentry *
+nfs4_remote_mount(struct file_system_type *fs_type, int flags,
+		  const char *dev_name, void *raw_data)
+{
+	struct nfs_parsed_mount_data *data = raw_data;
+	struct super_block *s;
+	struct nfs_server *server;
+	struct nfs_fh *mntfh;
+	struct dentry *mntroot;
+	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
+	struct nfs_sb_mountdata sb_mntdata = {
+		.mntflags = flags,
+	};
+	int error = -ENOMEM;
+
+	mntfh = nfs_alloc_fhandle();
+	if (data == NULL || mntfh == NULL)
+		goto out;
+
+	/* Get a volume representation */
+	server = nfs4_create_server(data, mntfh);
+	if (IS_ERR(server)) {
+		error = PTR_ERR(server);
+		goto out;
+	}
+	sb_mntdata.server = server;
+
+	if (server->flags & NFS4_MOUNT_UNSHARED)
+		compare_super = NULL;
+
+	/* -o noac implies -o sync */
+	if (server->flags & NFS_MOUNT_NOAC)
+		sb_mntdata.mntflags |= MS_SYNCHRONOUS;
+
+	/* Get a superblock - note that we may end up sharing one that already exists */
+	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
+	if (IS_ERR(s)) {
+		error = PTR_ERR(s);
+		goto out_free;
+	}
+
+	if (s->s_fs_info != server) {
+		nfs_free_server(server);
+		server = NULL;
+	} else {
+		error = nfs_bdi_register(server);
+		if (error)
+			goto error_splat_bdi;
+	}
+
+	if (!s->s_root) {
+		/* initial superblock/root creation */
+		nfs4_fill_super(s);
+		nfs_fscache_get_super_cookie(s, data->fscache_uniq, NULL);
+	}
+
+	mntroot = nfs4_get_root(s, mntfh, dev_name);
+	if (IS_ERR(mntroot)) {
+		error = PTR_ERR(mntroot);
+		goto error_splat_super;
+	}
+
+	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
+	if (error)
+		goto error_splat_root;
+
+	s->s_flags |= MS_ACTIVE;
+
+	nfs_free_fhandle(mntfh);
+	return mntroot;
+
+out:
+	nfs_free_fhandle(mntfh);
+	return ERR_PTR(error);
+
+out_free:
+	nfs_free_server(server);
+	goto out;
+
+error_splat_root:
+	dput(mntroot);
+error_splat_super:
+	if (server && !s->s_root)
+		bdi_unregister(&server->backing_dev_info);
+error_splat_bdi:
+	deactivate_locked_super(s);
+	goto out;
+}
+
+static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
+		int flags, void *data, const char *hostname)
+{
+	struct vfsmount *root_mnt;
+	char *root_devname;
+	size_t len;
+
+	len = strlen(hostname) + 5;
+	root_devname = kmalloc(len, GFP_KERNEL);
+	if (root_devname == NULL)
+		return ERR_PTR(-ENOMEM);
+	/* Does hostname needs to be enclosed in brackets? */
+	if (strchr(hostname, ':'))
+		snprintf(root_devname, len, "[%s]:/", hostname);
+	else
+		snprintf(root_devname, len, "%s:/", hostname);
+	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
+	kfree(root_devname);
+	return root_mnt;
+}
+
+struct nfs_referral_count {
+	struct list_head list;
+	const struct task_struct *task;
+	unsigned int referral_count;
+};
+
+static LIST_HEAD(nfs_referral_count_list);
+static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
+
+static struct nfs_referral_count *nfs_find_referral_count(void)
+{
+	struct nfs_referral_count *p;
+
+	list_for_each_entry(p, &nfs_referral_count_list, list) {
+		if (p->task == current)
+			return p;
+	}
+	return NULL;
+}
+
+#define NFS_MAX_NESTED_REFERRALS 2
+
+static int nfs_referral_loop_protect(void)
+{
+	struct nfs_referral_count *p, *new;
+	int ret = -ENOMEM;
+
+	new = kmalloc(sizeof(*new), GFP_KERNEL);
+	if (!new)
+		goto out;
+	new->task = current;
+	new->referral_count = 1;
+
+	ret = 0;
+	spin_lock(&nfs_referral_count_list_lock);
+	p = nfs_find_referral_count();
+	if (p != NULL) {
+		if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
+			ret = -ELOOP;
+		else
+			p->referral_count++;
+	} else {
+		list_add(&new->list, &nfs_referral_count_list);
+		new = NULL;
+	}
+	spin_unlock(&nfs_referral_count_list_lock);
+	kfree(new);
+out:
+	return ret;
+}
+
+static void nfs_referral_loop_unprotect(void)
+{
+	struct nfs_referral_count *p;
+
+	spin_lock(&nfs_referral_count_list_lock);
+	p = nfs_find_referral_count();
+	p->referral_count--;
+	if (p->referral_count == 0)
+		list_del(&p->list);
+	else
+		p = NULL;
+	spin_unlock(&nfs_referral_count_list_lock);
+	kfree(p);
+}
+
+static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt,
+		const char *export_path)
+{
+	struct dentry *dentry;
+	int err;
+
+	if (IS_ERR(root_mnt))
+		return ERR_CAST(root_mnt);
+
+	err = nfs_referral_loop_protect();
+	if (err) {
+		mntput(root_mnt);
+		return ERR_PTR(err);
+	}
+
+	dentry = mount_subtree(root_mnt, export_path);
+	nfs_referral_loop_unprotect();
+
+	return dentry;
+}
+
+static struct dentry *nfs4_try_mount(int flags, const char *dev_name,
+			 struct nfs_parsed_mount_data *data)
+{
+	char *export_path;
+	struct vfsmount *root_mnt;
+	struct dentry *res;
+
+	dfprintk(MOUNT, "--> nfs4_try_mount()\n");
+
+	export_path = data->nfs_server.export_path;
+	data->nfs_server.export_path = "/";
+	root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, data,
+			data->nfs_server.hostname);
+	data->nfs_server.export_path = export_path;
+
+	res = nfs_follow_remote_path(root_mnt, export_path);
+
+	dfprintk(MOUNT, "<-- nfs4_try_mount() = %ld%s\n",
+			IS_ERR(res) ? PTR_ERR(res) : 0,
+			IS_ERR(res) ? " [error]" : "");
+	return res;
+}
+
+/*
+ * Get the superblock for an NFS4 mountpoint
+ */
+static struct dentry *nfs4_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *raw_data)
+{
+	struct nfs_parsed_mount_data *data;
+	int error = -ENOMEM;
+	struct dentry *res = ERR_PTR(-ENOMEM);
+
+	data = nfs_alloc_parsed_mount_data(4);
+	if (data == NULL)
+		goto out;
+
+	/* Validate the mount data */
+	error = nfs4_validate_mount_data(raw_data, data, dev_name);
+	if (error < 0) {
+		res = ERR_PTR(error);
+		goto out;
+	}
+
+	res = nfs4_try_mount(flags, dev_name, data);
+	if (IS_ERR(res))
+		error = PTR_ERR(res);
+
+out:
+	nfs_free_parsed_mount_data(data);
+	dprintk("<-- nfs4_mount() = %d%s\n", error,
+			error != 0 ? " [error]" : "");
+	return res;
+}
+
+static void nfs4_kill_super(struct super_block *sb)
+{
+	struct nfs_server *server = NFS_SB(sb);
+
+	dprintk("--> %s\n", __func__);
+	nfs_super_return_all_delegations(sb);
+	kill_anon_super(sb);
+	nfs_fscache_release_super_cookie(sb);
+	nfs_free_server(server);
+	dprintk("<-- %s\n", __func__);
+}
+
+/*
+ * Clone an NFS4 server record on xdev traversal (FSID-change)
+ */
+static struct dentry *
+nfs4_xdev_mount(struct file_system_type *fs_type, int flags,
+		 const char *dev_name, void *raw_data)
+{
+	struct nfs_clone_mount *data = raw_data;
+	struct super_block *s;
+	struct nfs_server *server;
+	struct dentry *mntroot;
+	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
+	struct nfs_sb_mountdata sb_mntdata = {
+		.mntflags = flags,
+	};
+	int error;
+
+	dprintk("--> nfs4_xdev_mount()\n");
+
+	/* create a new volume representation */
+	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr, data->authflavor);
+	if (IS_ERR(server)) {
+		error = PTR_ERR(server);
+		goto out_err_noserver;
+	}
+	sb_mntdata.server = server;
+
+	if (server->flags & NFS4_MOUNT_UNSHARED)
+		compare_super = NULL;
+
+	/* -o noac implies -o sync */
+	if (server->flags & NFS_MOUNT_NOAC)
+		sb_mntdata.mntflags |= MS_SYNCHRONOUS;
+
+	/* Get a superblock - note that we may end up sharing one that already exists */
+	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
+	if (IS_ERR(s)) {
+		error = PTR_ERR(s);
+		goto out_err_nosb;
+	}
+
+	if (s->s_fs_info != server) {
+		nfs_free_server(server);
+		server = NULL;
+	} else {
+		error = nfs_bdi_register(server);
+		if (error)
+			goto error_splat_bdi;
+	}
+
+	if (!s->s_root) {
+		/* initial superblock/root creation */
+		nfs4_clone_super(s, data->sb);
+		nfs_fscache_get_super_cookie(s, NULL, data);
+	}
+
+	mntroot = nfs4_get_root(s, data->fh, dev_name);
+	if (IS_ERR(mntroot)) {
+		error = PTR_ERR(mntroot);
+		goto error_splat_super;
+	}
+	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
+		dput(mntroot);
+		error = -ESTALE;
+		goto error_splat_super;
+	}
+
+	s->s_flags |= MS_ACTIVE;
+
+	security_sb_clone_mnt_opts(data->sb, s);
+
+	dprintk("<-- nfs4_xdev_mount() = 0\n");
+	return mntroot;
+
+out_err_nosb:
+	nfs_free_server(server);
+out_err_noserver:
+	dprintk("<-- nfs4_xdev_mount() = %d [error]\n", error);
+	return ERR_PTR(error);
+
+error_splat_super:
+	if (server && !s->s_root)
+		bdi_unregister(&server->backing_dev_info);
+error_splat_bdi:
+	deactivate_locked_super(s);
+	dprintk("<-- nfs4_xdev_mount() = %d [splat]\n", error);
+	return ERR_PTR(error);
+}
+
+static struct dentry *
+nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
+			   const char *dev_name, void *raw_data)
+{
+	struct nfs_clone_mount *data = raw_data;
+	struct super_block *s;
+	struct nfs_server *server;
+	struct dentry *mntroot;
+	struct nfs_fh *mntfh;
+	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
+	struct nfs_sb_mountdata sb_mntdata = {
+		.mntflags = flags,
+	};
+	int error = -ENOMEM;
+
+	dprintk("--> nfs4_referral_get_sb()\n");
+
+	mntfh = nfs_alloc_fhandle();
+	if (mntfh == NULL)
+		goto out_err_nofh;
+
+	/* create a new volume representation */
+	server = nfs4_create_referral_server(data, mntfh);
+	if (IS_ERR(server)) {
+		error = PTR_ERR(server);
+		goto out_err_noserver;
+	}
+	sb_mntdata.server = server;
+
+	if (server->flags & NFS4_MOUNT_UNSHARED)
+		compare_super = NULL;
+
+	/* -o noac implies -o sync */
+	if (server->flags & NFS_MOUNT_NOAC)
+		sb_mntdata.mntflags |= MS_SYNCHRONOUS;
+
+	/* Get a superblock - note that we may end up sharing one that already exists */
+	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
+	if (IS_ERR(s)) {
+		error = PTR_ERR(s);
+		goto out_err_nosb;
+	}
+
+	if (s->s_fs_info != server) {
+		nfs_free_server(server);
+		server = NULL;
+	} else {
+		error = nfs_bdi_register(server);
+		if (error)
+			goto error_splat_bdi;
+	}
+
+	if (!s->s_root) {
+		/* initial superblock/root creation */
+		nfs4_fill_super(s);
+		nfs_fscache_get_super_cookie(s, NULL, data);
+	}
+
+	mntroot = nfs4_get_root(s, mntfh, dev_name);
+	if (IS_ERR(mntroot)) {
+		error = PTR_ERR(mntroot);
+		goto error_splat_super;
+	}
+	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
+		dput(mntroot);
+		error = -ESTALE;
+		goto error_splat_super;
+	}
+
+	s->s_flags |= MS_ACTIVE;
+
+	security_sb_clone_mnt_opts(data->sb, s);
+
+	nfs_free_fhandle(mntfh);
+	dprintk("<-- nfs4_referral_get_sb() = 0\n");
+	return mntroot;
+
+out_err_nosb:
+	nfs_free_server(server);
+out_err_noserver:
+	nfs_free_fhandle(mntfh);
+out_err_nofh:
+	dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
+	return ERR_PTR(error);
+
+error_splat_super:
+	if (server && !s->s_root)
+		bdi_unregister(&server->backing_dev_info);
+error_splat_bdi:
+	deactivate_locked_super(s);
+	nfs_free_fhandle(mntfh);
+	dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
+	return ERR_PTR(error);
+}
+
+/*
+ * Create an NFS4 server record on referral traversal
+ */
+static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
+		int flags, const char *dev_name, void *raw_data)
+{
+	struct nfs_clone_mount *data = raw_data;
+	char *export_path;
+	struct vfsmount *root_mnt;
+	struct dentry *res;
+
+	dprintk("--> nfs4_referral_mount()\n");
+
+	export_path = data->mnt_path;
+	data->mnt_path = "/";
+
+	root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
+			flags, data, data->hostname);
+	data->mnt_path = export_path;
+
+	res = nfs_follow_remote_path(root_mnt, export_path);
+	dprintk("<-- nfs4_referral_mount() = %ld%s\n",
+			IS_ERR(res) ? PTR_ERR(res) : 0,
+			IS_ERR(res) ? " [error]" : "");
+	return res;
+}
+
+MODULE_ALIAS("nfs4");
+
+#endif /* CONFIG_NFS_V4 */