/*
   *  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 <asm/system.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_v2, Opt_v3, Opt_v4,

  	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_nfsvers,

  	Opt_minorversion,

  
  	/* Mount options that take string arguments */

  	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_v2, "v2" },
  	{ Opt_v3, "v3" },

  	{ Opt_v4, "v4" },

  	{ 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_nfsvers, "nfsvers=%s" },
  	{ Opt_nfsvers, "vers=%s" },

  	{ Opt_minorversion, "minorversion=%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" },

  	{ 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 }
  };

  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
  ", __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);
  	seq_printf(m, ",minorversion=%u", clp->cl_minorversion);
  }
  #else
  static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
  				    int showdefaults)
  {
  }
  #endif

  /*
   * 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;

  	seq_printf(m, ",vers=%u", version);

  	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);
  	}

  	seq_printf(m, ",proto=%s",

  		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));

  	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);

  	seq_printf(m, ",addr=%s",
  			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
  							RPC_DISPLAY_ADDR));

  
  	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

  #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");
  }

  #else
  static void show_pnfs(struct seq_file *m, struct nfs_server *server) {}
  #endif
  #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);

  	if (IS_ERR(devname))
  		err = PTR_ERR(devname);
  	else
  		seq_escape(m, devname, " \t
  \\");
  	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, "
  \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, "
  \tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
  
  	seq_printf(m, "
  \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, "
  \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, "
  \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, "
  \tevents:\t");
  	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
  		seq_printf(m, "%lu ", totals.events[i]);
  	seq_printf(m, "
  \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, "
  \tfsc:\t");
  		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
  			seq_printf(m, "%Lu ", totals.bytes[i]);
  	}
  #endif

  	seq_printf(m, "
  ");
  
  	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;

  		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
  ");

  	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
  ", 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_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.
  ");
  		return 1;
  	}
  	dfprintk(MOUNT, "NFS: nfs mount opts='%s'
  ", 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'
  ", 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_v2:
  			mnt->flags &= ~NFS_MOUNT_VER3;

  			mnt->version = 2;

  			break;
  		case Opt_v3:
  			mnt->flags |= NFS_MOUNT_VER3;

  			mnt->version = 3;

  			break;

  		case Opt_v4:
  			mnt->flags &= ~NFS_MOUNT_VER3;
  			mnt->version = 4;
  			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_nfsvers:

  			if (nfs_get_option_ul(args, &option))

  				goto out_invalid_value;

  			switch (option) {

  			case NFS2_VERSION:

  				mnt->flags &= ~NFS_MOUNT_VER3;

  				mnt->version = 2;

  				break;

  			case NFS3_VERSION:

  				mnt->flags |= NFS_MOUNT_VER3;

  				mnt->version = 3;
  				break;

  			case NFS4_VERSION:
  				mnt->flags &= ~NFS_MOUNT_VER3;
  				mnt->version = 4;

  				break;
  			default:

  				goto out_invalid_value;

  			}
  			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_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
  ");

  				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
  ");

  				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
  ");

  				return 0;

  			}
  			break;
  		case Opt_addr:
  			string = match_strdup(args);
  			if (string == NULL)
  				goto out_nomem;

  			mnt->nfs_server.addrlen =
  				rpc_pton(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(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
  ");

  					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
  ");
  				return 0;
  			};
  			break;

  		/*
  		 * Special options
  		 */
  		case Opt_sloppy:
  			sloppy = 1;
  			dfprintk(MOUNT, "NFS:   relaxing parsing rules
  ");
  			break;

  		case Opt_userspace:
  		case Opt_deprecated:

  			dfprintk(MOUNT, "NFS:   ignoring mount option "
  					"'%s'
  ", p);

  			break;
  
  		default:

  			invalid_option = 1;

  			dfprintk(MOUNT, "NFS:   unrecognized mount option "
  					"'%s'
  ", p);

  		}
  	}

  	if (!sloppy && invalid_option)
  		return 0;

  	/*
  	 * 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
  ");
  	return 0;
  out_proto_mismatch:
  	printk(KERN_INFO "NFS: server address does not match proto= option
  ");
  	return 0;

  out_invalid_address:
  	printk(KERN_INFO "NFS: bad IP address specified: %s
  ", p);
  	return 0;

  out_invalid_value:

  	printk(KERN_INFO "NFS: bad mount option value specified: %s
  ", p);

  	return 0;

  out_nomem:
  	printk(KERN_INFO "NFS: not enough memory to parse option
  ");
  	return 0;

  out_security_failure:
  	free_secdata(secdata);
  	printk(KERN_INFO "NFS: security options invalid: %d
  ", 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
  ",
  					request->auth_flavs[j]);
  				args->auth_flavors[0] = request->auth_flavs[j];
  				return 0;
  			}
  
  	dfprintk(MOUNT, "NFS: server does not support requested auth flavor
  ");
  	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,

  	};

  	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
  ",
  				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'
  ", *export_path);

  	return 0;
  
  out_bad_devname:
  	dfprintk(MOUNT, "NFS: device name not in host:path format
  ");
  	return -EINVAL;
  
  out_nomem:
  	dfprintk(MOUNT, "NFS: not enough memory to parse device name
  ");
  	return -ENOMEM;
  
  out_hostname:
  	dfprintk(MOUNT, "NFS: server hostname too long
  ");
  	return -ENAMETOOLONG;
  
  out_path:
  	dfprintk(MOUNT, "NFS: export pathname too long
  ");
  	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);

  		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;