NFS: Split fs/nfs/inode.c

As fs/nfs/inode.c is rather large, heterogenous and unwieldy, the attached
patch splits it up into a number of files:

 (*) fs/nfs/inode.c

     Strictly inode specific functions.

 (*) fs/nfs/super.c

     Superblock management functions for NFS and NFS4, normal access, clones
     and referrals.  The NFS4 superblock functions _could_ move out into a
     separate conditionally compiled file, but it's probably not worth it as
     there're so many common bits.

 (*) fs/nfs/namespace.c

     Some namespace-specific functions have been moved here.

 (*) fs/nfs/nfs4namespace.c

     NFS4-specific namespace functions (this could be merged into the previous
     file).  This file is conditionally compiled.

 (*) fs/nfs/internal.h

     Inter-file declarations, plus a few simple utility functions moved from
     fs/nfs/inode.c.

     Additionally, all the in-.c-file externs have been moved here, and those
     files they were moved from now includes this file.

For the most part, the functions have not been changed, only some multiplexor
functions have changed significantly.

I've also:

 (*) Added some extra banner comments above some functions.

 (*) Rearranged the function order within the files to be more logical and
     better grouped (IMO), though someone may prefer a different order.

 (*) Reduced the number of #ifdefs in .c files.

 (*) Added missing __init and __exit directives.

Signed-Off-By: David Howells <dhowells@redhat.com>

1 files changed, 1468 insertions, 0 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
new file mode 100644
index 000000000000..4acd3ee96427
--- /dev/null
+++ b/fs/nfs/super.c
@@ -0,0 +1,1468 @@
+/*
+ *  linux/fs/nfs/super.c
+ *
+ *  Copyright (C) 1992  Rick Sladkey
+ *
+ *  nfs superblock handling functions
+ *
+ *  Modularised by Alan Cox <Alan.Cox@linux.org>, 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>
+ *
+ */
+
+#include <linux/config.h>
+#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/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/nfs4_mount.h>
+#include <linux/lockd/bind.h>
+#include <linux/smp_lock.h>
+#include <linux/seq_file.h>
+#include <linux/mount.h>
+#include <linux/nfs_idmap.h>
+#include <linux/vfs.h>
+#include <linux/inet.h>
+#include <linux/nfs_xdr.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"
+
+#define NFSDBG_FACILITY		NFSDBG_VFS
+
+/* Maximum number of readahead requests
+ * FIXME: this should really be a sysctl so that users may tune it to suit
+ *        their needs. People that do NFS over a slow network, might for
+ *        instance want to reduce it to something closer to 1 for improved
+ *        interactive response.
+ */
+#define NFS_MAX_READAHEAD	(RPC_DEF_SLOT_TABLE - 1)
+
+/*
+ * RPC cruft for NFS
+ */
+static struct rpc_version * nfs_version[] = {
+	NULL,
+	NULL,
+	&nfs_version2,
+#if defined(CONFIG_NFS_V3)
+	&nfs_version3,
+#elif defined(CONFIG_NFS_V4)
+	NULL,
+#endif
+#if defined(CONFIG_NFS_V4)
+	&nfs_version4,
+#endif
+};
+
+static struct rpc_program nfs_program = {
+	.name			= "nfs",
+	.number			= NFS_PROGRAM,
+	.nrvers			= ARRAY_SIZE(nfs_version),
+	.version		= nfs_version,
+	.stats			= &nfs_rpcstat,
+	.pipe_dir_name		= "/nfs",
+};
+
+struct rpc_stat nfs_rpcstat = {
+	.program		= &nfs_program
+};
+
+
+#ifdef CONFIG_NFS_V3_ACL
+static struct rpc_stat		nfsacl_rpcstat = { &nfsacl_program };
+static struct rpc_version *	nfsacl_version[] = {
+	[3]			= &nfsacl_version3,
+};
+
+struct rpc_program		nfsacl_program = {
+	.name =			"nfsacl",
+	.number =		NFS_ACL_PROGRAM,
+	.nrvers =		ARRAY_SIZE(nfsacl_version),
+	.version =		nfsacl_version,
+	.stats =		&nfsacl_rpcstat,
+};
+#endif  /* CONFIG_NFS_V3_ACL */
+
+static void nfs_umount_begin(struct vfsmount *, int);
+static int  nfs_statfs(struct super_block *, struct kstatfs *);
+static int  nfs_show_options(struct seq_file *, struct vfsmount *);
+static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
+static struct super_block *nfs_get_sb(struct file_system_type *, int, const char *, void *);
+static struct super_block *nfs_clone_nfs_sb(struct file_system_type *fs_type,
+		int flags, const char *dev_name, void *raw_data);
+static void nfs_kill_super(struct super_block *);
+
+static struct file_system_type nfs_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "nfs",
+	.get_sb		= nfs_get_sb,
+	.kill_sb	= nfs_kill_super,
+	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
+struct file_system_type clone_nfs_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "nfs",
+	.get_sb		= nfs_clone_nfs_sb,
+	.kill_sb	= nfs_kill_super,
+	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
+static struct super_operations nfs_sops = {
+	.alloc_inode	= nfs_alloc_inode,
+	.destroy_inode	= nfs_destroy_inode,
+	.write_inode	= nfs_write_inode,
+	.statfs		= nfs_statfs,
+	.clear_inode	= nfs_clear_inode,
+	.umount_begin	= nfs_umount_begin,
+	.show_options	= nfs_show_options,
+	.show_stats	= nfs_show_stats,
+};
+
+#ifdef CONFIG_NFS_V4
+static struct super_block *nfs4_get_sb(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *raw_data);
+static struct super_block *nfs_clone_nfs4_sb(struct file_system_type *fs_type,
+		int flags, const char *dev_name, void *raw_data);
+static struct super_block *nfs_referral_nfs4_sb(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",
+	.get_sb		= nfs4_get_sb,
+	.kill_sb	= nfs4_kill_super,
+	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
+struct file_system_type clone_nfs4_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "nfs4",
+	.get_sb		= nfs_clone_nfs4_sb,
+	.kill_sb	= nfs4_kill_super,
+	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
+struct file_system_type nfs_referral_nfs4_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "nfs4",
+	.get_sb		= nfs_referral_nfs4_sb,
+	.kill_sb	= nfs4_kill_super,
+	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+};
+
+static struct super_operations nfs4_sops = {
+	.alloc_inode	= nfs_alloc_inode,
+	.destroy_inode	= nfs_destroy_inode,
+	.write_inode	= nfs_write_inode,
+	.statfs		= nfs_statfs,
+	.clear_inode	= nfs4_clear_inode,
+	.umount_begin	= nfs_umount_begin,
+	.show_options	= nfs_show_options,
+	.show_stats	= nfs_show_stats,
+};
+#endif
+
+static const int nfs_set_port_min = 0;
+static const int nfs_set_port_max = 65535;
+
+static int param_set_port(const char *val, struct kernel_param *kp)
+{
+	char *endp;
+	int num = simple_strtol(val, &endp, 0);
+	if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max)
+		return -EINVAL;
+	*((int *)kp->arg) = num;
+	return 0;
+}
+
+module_param_call(callback_tcpport, param_set_port, param_get_int,
+		 &nfs_callback_set_tcpport, 0644);
+
+static int param_set_idmap_timeout(const char *val, struct kernel_param *kp)
+{
+	char *endp;
+	int num = simple_strtol(val, &endp, 0);
+	int jif = num * HZ;
+	if (endp == val || *endp || num < 0 || jif < num)
+		return -EINVAL;
+	*((int *)kp->arg) = jif;
+	return 0;
+}
+
+module_param_call(idmap_cache_timeout, param_set_idmap_timeout, param_get_int,
+		 &nfs_idmap_cache_timeout, 0644);
+
+/*
+ * Register the NFS filesystems
+ */
+int __init register_nfs_fs(void)
+{
+	int ret;
+
+        ret = register_filesystem(&nfs_fs_type);
+	if (ret < 0)
+		goto error_0;
+
+#ifdef CONFIG_NFS_V4
+	ret = nfs_register_sysctl();
+	if (ret < 0)
+		goto error_1;
+	ret = register_filesystem(&nfs4_fs_type);
+	if (ret < 0)
+		goto error_2;
+#endif
+	return 0;
+
+#ifdef CONFIG_NFS_V4
+error_2:
+	nfs_unregister_sysctl();
+error_1:
+	unregister_filesystem(&nfs_fs_type);
+#endif
+error_0:
+	return ret;
+}
+
+/*
+ * Unregister the NFS filesystems
+ */
+void __exit unregister_nfs_fs(void)
+{
+#ifdef CONFIG_NFS_V4
+	unregister_filesystem(&nfs4_fs_type);
+	nfs_unregister_sysctl();
+#endif
+	unregister_filesystem(&nfs_fs_type);
+}
+
+/*
+ * Deliver file system statistics to userspace
+ */
+static int nfs_statfs(struct super_block *sb, struct kstatfs *buf)
+{
+	struct nfs_server *server = NFS_SB(sb);
+	unsigned char blockbits;
+	unsigned long blockres;
+	struct nfs_fh *rootfh = NFS_FH(sb->s_root->d_inode);
+	struct nfs_fattr fattr;
+	struct nfs_fsstat res = {
+			.fattr = &fattr,
+	};
+	int error;
+
+	lock_kernel();
+
+	error = server->rpc_ops->statfs(server, rootfh, &res);
+	buf->f_type = NFS_SUPER_MAGIC;
+	if (error < 0)
+		goto out_err;
+
+	/*
+	 * 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 = 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 = sb->s_blocksize;
+	blockbits = 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;
+ out:
+	unlock_kernel();
+	return 0;
+
+ out_err:
+	dprintk("%s: statfs error = %d\n", __FUNCTION__, -error);
+	buf->f_bsize = buf->f_blocks = buf->f_bfree = buf->f_bavail = -1;
+	goto out;
+
+}
+
+/*
+ * 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 struct proc_nfs_info {
+		int flag;
+		char *str;
+		char *nostr;
+	} nfs_info[] = {
+		{ NFS_MOUNT_SOFT, ",soft", ",hard" },
+		{ NFS_MOUNT_INTR, ",intr", "" },
+		{ NFS_MOUNT_NOCTO, ",nocto", "" },
+		{ NFS_MOUNT_NOAC, ",noac", "" },
+		{ NFS_MOUNT_NONLM, ",nolock", "" },
+		{ NFS_MOUNT_NOACL, ",noacl", "" },
+		{ 0, NULL, NULL }
+	};
+	struct proc_nfs_info *nfs_infop;
+	char buf[12];
+	char *proto;
+
+	seq_printf(m, ",vers=%d", nfss->rpc_ops->version);
+	seq_printf(m, ",rsize=%d", nfss->rsize);
+	seq_printf(m, ",wsize=%d", nfss->wsize);
+	if (nfss->acregmin != 3*HZ || showdefaults)
+		seq_printf(m, ",acregmin=%d", nfss->acregmin/HZ);
+	if (nfss->acregmax != 60*HZ || showdefaults)
+		seq_printf(m, ",acregmax=%d", nfss->acregmax/HZ);
+	if (nfss->acdirmin != 30*HZ || showdefaults)
+		seq_printf(m, ",acdirmin=%d", nfss->acdirmin/HZ);
+	if (nfss->acdirmax != 60*HZ || showdefaults)
+		seq_printf(m, ",acdirmax=%d", 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);
+	}
+	switch (nfss->client->cl_xprt->prot) {
+		case IPPROTO_TCP:
+			proto = "tcp";
+			break;
+		case IPPROTO_UDP:
+			proto = "udp";
+			break;
+		default:
+			snprintf(buf, sizeof(buf), "%u", nfss->client->cl_xprt->prot);
+			proto = buf;
+	}
+	seq_printf(m, ",proto=%s", proto);
+	seq_printf(m, ",timeo=%lu", 10U * nfss->retrans_timeo / HZ);
+	seq_printf(m, ",retrans=%u", nfss->retrans_count);
+}
+
+/*
+ * Describe the mount options on this VFS mountpoint
+ */
+static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
+{
+	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
+
+	nfs_show_mount_options(m, nfss, 0);
+
+	seq_puts(m, ",addr=");
+	seq_escape(m, nfss->hostname, " \t\n\\");
+
+	return 0;
+}
+
+/*
+ * Present statistical information for this VFS mountpoint
+ */
+static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
+{
+	int i, cpu;
+	struct nfs_server *nfss = NFS_SB(mnt->mnt_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, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
+	seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
+	seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
+	seq_puts(m, mnt->mnt_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);
+
+	seq_printf(m, "\n\tcaps:\t");
+	seq_printf(m, "caps=0x%x", nfss->caps);
+	seq_printf(m, ",wtmult=%d", nfss->wtmult);
+	seq_printf(m, ",dtsize=%d", nfss->dtsize);
+	seq_printf(m, ",bsize=%d", nfss->bsize);
+	seq_printf(m, ",namelen=%d", nfss->namelen);
+
+#ifdef CONFIG_NFS_V4
+	if (nfss->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);
+	}
+#endif
+
+	/*
+	 * Display security flavor in effect for this mount
+	 */
+	seq_printf(m, "\n\tsec:\tflavor=%d", auth->au_ops->au_flavor);
+	if (auth->au_flavor)
+		seq_printf(m, ",pseudoflavor=%d", 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];
+
+		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]);
+	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 traversals
+ */
+static void nfs_umount_begin(struct vfsmount *vfsmnt, int flags)
+{
+	struct nfs_server *server;
+	struct rpc_clnt	*rpc;
+
+	shrink_submounts(vfsmnt, &nfs_automount_list);
+	if (!(flags & MNT_FORCE))
+		return;
+	/* -EIO all pending I/O */
+	server = NFS_SB(vfsmnt->mnt_sb);
+	rpc = server->client;
+	if (!IS_ERR(rpc))
+		rpc_killall_tasks(rpc);
+	rpc = server->client_acl;
+	if (!IS_ERR(rpc))
+		rpc_killall_tasks(rpc);
+}
+
+/*
+ * Obtain the root inode of the file system.
+ */
+static struct inode *
+nfs_get_root(struct super_block *sb, struct nfs_fh *rootfh, struct nfs_fsinfo *fsinfo)
+{
+	struct nfs_server	*server = NFS_SB(sb);
+	int			error;
+
+	error = server->rpc_ops->getroot(server, rootfh, fsinfo);
+	if (error < 0) {
+		dprintk("nfs_get_root: getattr error = %d\n", -error);
+		return ERR_PTR(error);
+	}
+
+	server->fsid = fsinfo->fattr->fsid;
+	return nfs_fhget(sb, rootfh, fsinfo->fattr);
+}
+
+/*
+ * Do NFS version-independent mount processing, and sanity checking
+ */
+static int
+nfs_sb_init(struct super_block *sb, rpc_authflavor_t authflavor)
+{
+	struct nfs_server	*server;
+	struct inode		*root_inode;
+	struct nfs_fattr	fattr;
+	struct nfs_fsinfo	fsinfo = {
+					.fattr = &fattr,
+				};
+	struct nfs_pathconf pathinfo = {
+			.fattr = &fattr,
+	};
+	int no_root_error = 0;
+	unsigned long max_rpc_payload;
+
+	/* We probably want something more informative here */
+	snprintf(sb->s_id, sizeof(sb->s_id), "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
+
+	server = NFS_SB(sb);
+
+	sb->s_magic      = NFS_SUPER_MAGIC;
+
+	server->io_stats = nfs_alloc_iostats();
+	if (server->io_stats == NULL)
+		return -ENOMEM;
+
+	root_inode = nfs_get_root(sb, &server->fh, &fsinfo);
+	/* Did getting the root inode fail? */
+	if (IS_ERR(root_inode)) {
+		no_root_error = PTR_ERR(root_inode);
+		goto out_no_root;
+	}
+	sb->s_root = d_alloc_root(root_inode);
+	if (!sb->s_root) {
+		no_root_error = -ENOMEM;
+		goto out_no_root;
+	}
+	sb->s_root->d_op = server->rpc_ops->dentry_ops;
+
+	/* mount time stamp, in seconds */
+	server->mount_time = jiffies;
+
+	/* Get some general file system info */
+	if (server->namelen == 0 &&
+	    server->rpc_ops->pathconf(server, &server->fh, &pathinfo) >= 0)
+		server->namelen = pathinfo.max_namelen;
+	/* Work out a lot of parameters */
+	if (server->rsize == 0)
+		server->rsize = nfs_block_size(fsinfo.rtpref, NULL);
+	if (server->wsize == 0)
+		server->wsize = nfs_block_size(fsinfo.wtpref, NULL);
+
+	if (fsinfo.rtmax >= 512 && server->rsize > fsinfo.rtmax)
+		server->rsize = nfs_block_size(fsinfo.rtmax, NULL);
+	if (fsinfo.wtmax >= 512 && server->wsize > fsinfo.wtmax)
+		server->wsize = nfs_block_size(fsinfo.wtmax, NULL);
+
+	max_rpc_payload = nfs_block_size(rpc_max_payload(server->client), NULL);
+	if (server->rsize > max_rpc_payload)
+		server->rsize = max_rpc_payload;
+	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
+		server->rsize = NFS_MAX_FILE_IO_SIZE;
+	server->rpages = (server->rsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+
+	if (server->wsize > max_rpc_payload)
+		server->wsize = max_rpc_payload;
+	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
+		server->wsize = NFS_MAX_FILE_IO_SIZE;
+	server->wpages = (server->wsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+
+	if (sb->s_blocksize == 0)
+		sb->s_blocksize = nfs_block_bits(server->wsize,
+							 &sb->s_blocksize_bits);
+	server->wtmult = nfs_block_bits(fsinfo.wtmult, NULL);
+
+	server->dtsize = nfs_block_size(fsinfo.dtpref, NULL);
+	if (server->dtsize > PAGE_CACHE_SIZE)
+		server->dtsize = PAGE_CACHE_SIZE;
+	if (server->dtsize > server->rsize)
+		server->dtsize = server->rsize;
+
+	if (server->flags & NFS_MOUNT_NOAC) {
+		server->acregmin = server->acregmax = 0;
+		server->acdirmin = server->acdirmax = 0;
+		sb->s_flags |= MS_SYNCHRONOUS;
+	}
+	server->backing_dev_info.ra_pages = server->rpages * NFS_MAX_READAHEAD;
+
+	nfs_super_set_maxbytes(sb, fsinfo.maxfilesize);
+
+	server->client->cl_intr = (server->flags & NFS_MOUNT_INTR) ? 1 : 0;
+	server->client->cl_softrtry = (server->flags & NFS_MOUNT_SOFT) ? 1 : 0;
+
+	/* We're airborne Set socket buffersize */
+	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
+	return 0;
+	/* Yargs. It didn't work out. */
+out_no_root:
+	dprintk("nfs_sb_init: get root inode failed: errno %d\n", -no_root_error);
+	if (!IS_ERR(root_inode))
+		iput(root_inode);
+	return no_root_error;
+}
+
+/*
+ * Initialise the timeout values for a connection
+ */
+static void nfs_init_timeout_values(struct rpc_timeout *to, int proto, unsigned int timeo, unsigned int retrans)
+{
+	to->to_initval = timeo * HZ / 10;
+	to->to_retries = retrans;
+	if (!to->to_retries)
+		to->to_retries = 2;
+
+	switch (proto) {
+	case IPPROTO_TCP:
+		if (!to->to_initval)
+			to->to_initval = 60 * HZ;
+		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
+			to->to_initval = NFS_MAX_TCP_TIMEOUT;
+		to->to_increment = to->to_initval;
+		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
+		to->to_exponential = 0;
+		break;
+	case IPPROTO_UDP:
+	default:
+		if (!to->to_initval)
+			to->to_initval = 11 * HZ / 10;
+		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
+			to->to_initval = NFS_MAX_UDP_TIMEOUT;
+		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
+		to->to_exponential = 1;
+		break;
+	}
+}
+
+/*
+ * Create an RPC client handle.
+ */
+static struct rpc_clnt *
+nfs_create_client(struct nfs_server *server, const struct nfs_mount_data *data)
+{
+	struct rpc_timeout	timeparms;
+	struct rpc_xprt		*xprt = NULL;
+	struct rpc_clnt		*clnt = NULL;
+	int			proto = (data->flags & NFS_MOUNT_TCP) ? IPPROTO_TCP : IPPROTO_UDP;
+
+	nfs_init_timeout_values(&timeparms, proto, data->timeo, data->retrans);
+
+	server->retrans_timeo = timeparms.to_initval;
+	server->retrans_count = timeparms.to_retries;
+
+	/* create transport and client */
+	xprt = xprt_create_proto(proto, &server->addr, &timeparms);
+	if (IS_ERR(xprt)) {
+		dprintk("%s: cannot create RPC transport. Error = %ld\n",
+				__FUNCTION__, PTR_ERR(xprt));
+		return (struct rpc_clnt *)xprt;
+	}
+	clnt = rpc_create_client(xprt, server->hostname, &nfs_program,
+				 server->rpc_ops->version, data->pseudoflavor);
+	if (IS_ERR(clnt)) {
+		dprintk("%s: cannot create RPC client. Error = %ld\n",
+				__FUNCTION__, PTR_ERR(xprt));
+		goto out_fail;
+	}
+
+	clnt->cl_intr     = 1;
+	clnt->cl_softrtry = 1;
+
+	return clnt;
+
+out_fail:
+	return clnt;
+}
+
+/*
+ * Clone a server record
+ */
+static struct nfs_server *nfs_clone_server(struct super_block *sb, struct nfs_clone_mount *data)
+{
+	struct nfs_server *server = NFS_SB(sb);
+	struct nfs_server *parent = NFS_SB(data->sb);
+	struct inode *root_inode;
+	struct nfs_fsinfo fsinfo;
+	void *err = ERR_PTR(-ENOMEM);
+
+	sb->s_op = data->sb->s_op;
+	sb->s_blocksize = data->sb->s_blocksize;
+	sb->s_blocksize_bits = data->sb->s_blocksize_bits;
+	sb->s_maxbytes = data->sb->s_maxbytes;
+
+	server->client_sys = server->client_acl = ERR_PTR(-EINVAL);
+	server->io_stats = nfs_alloc_iostats();
+	if (server->io_stats == NULL)
+		goto out;
+
+	server->client = rpc_clone_client(parent->client);
+	if (IS_ERR((err = server->client)))
+		goto out;
+
+	if (!IS_ERR(parent->client_sys)) {
+		server->client_sys = rpc_clone_client(parent->client_sys);
+		if (IS_ERR((err = server->client_sys)))
+			goto out;
+	}
+	if (!IS_ERR(parent->client_acl)) {
+		server->client_acl = rpc_clone_client(parent->client_acl);
+		if (IS_ERR((err = server->client_acl)))
+			goto out;
+	}
+	root_inode = nfs_fhget(sb, data->fh, data->fattr);
+	if (!root_inode)
+		goto out;
+	sb->s_root = d_alloc_root(root_inode);
+	if (!sb->s_root)
+		goto out_put_root;
+	fsinfo.fattr = data->fattr;
+	if (NFS_PROTO(root_inode)->fsinfo(server, data->fh, &fsinfo) == 0)
+		nfs_super_set_maxbytes(sb, fsinfo.maxfilesize);
+	sb->s_root->d_op = server->rpc_ops->dentry_ops;
+	sb->s_flags |= MS_ACTIVE;
+	return server;
+out_put_root:
+	iput(root_inode);
+out:
+	return err;
+}
+
+/*
+ * Copy an existing superblock and attach revised data
+ */
+static struct super_block *nfs_clone_generic_sb(struct nfs_clone_mount *data,
+		struct super_block *(*fill_sb)(struct nfs_server *, struct nfs_clone_mount *),
+		struct nfs_server *(*fill_server)(struct super_block *, struct nfs_clone_mount *))
+{
+	struct nfs_server *server;
+	struct nfs_server *parent = NFS_SB(data->sb);
+	struct super_block *sb = ERR_PTR(-EINVAL);
+	void *err = ERR_PTR(-ENOMEM);
+	char *hostname;
+	int len;
+
+	server = kmalloc(sizeof(struct nfs_server), GFP_KERNEL);
+	if (server == NULL)
+		goto out_err;
+	memcpy(server, parent, sizeof(*server));
+	hostname = (data->hostname != NULL) ? data->hostname : parent->hostname;
+	len = strlen(hostname) + 1;
+	server->hostname = kmalloc(len, GFP_KERNEL);
+	if (server->hostname == NULL)
+		goto free_server;
+	memcpy(server->hostname, hostname, len);
+	if (rpciod_up() != 0)
+		goto free_hostname;
+
+	sb = fill_sb(server, data);
+	if (IS_ERR((err = sb)) || sb->s_root)
+		goto kill_rpciod;
+
+	server = fill_server(sb, data);
+	if (IS_ERR((err = server)))
+		goto out_deactivate;
+	return sb;
+out_deactivate:
+	up_write(&sb->s_umount);
+	deactivate_super(sb);
+	return (struct super_block *)err;
+kill_rpciod:
+	rpciod_down();
+free_hostname:
+	kfree(server->hostname);
+free_server:
+	kfree(server);
+out_err:
+	return (struct super_block *)err;
+}
+
+/*
+ * Set up an NFS2/3 superblock
+ *
+ * The way this works is that the mount process passes a structure
+ * in the data argument which contains the server's IP address
+ * and the root file handle obtained from the server's mount
+ * daemon. We stash these away in the private superblock fields.
+ */
+static int
+nfs_fill_super(struct super_block *sb, struct nfs_mount_data *data, int silent)
+{
+	struct nfs_server	*server;
+	rpc_authflavor_t	authflavor;
+
+	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 (data->rsize)
+		server->rsize = nfs_block_size(data->rsize, NULL);
+	if (data->wsize)
+		server->wsize = nfs_block_size(data->wsize, NULL);
+	server->flags    = data->flags & NFS_MOUNT_FLAGMASK;
+
+	server->acregmin = data->acregmin*HZ;
+	server->acregmax = data->acregmax*HZ;
+	server->acdirmin = data->acdirmin*HZ;
+	server->acdirmax = data->acdirmax*HZ;
+
+	/* Start lockd here, before we might error out */
+	if (!(server->flags & NFS_MOUNT_NONLM))
+		lockd_up();
+
+	server->namelen  = data->namlen;
+	server->hostname = kmalloc(strlen(data->hostname) + 1, GFP_KERNEL);
+	if (!server->hostname)
+		return -ENOMEM;
+	strcpy(server->hostname, data->hostname);
+
+	/* Check NFS protocol revision and initialize RPC op vector
+	 * and file handle pool. */
+#ifdef CONFIG_NFS_V3
+	if (server->flags & NFS_MOUNT_VER3) {
+		server->rpc_ops = &nfs_v3_clientops;
+		server->caps |= NFS_CAP_READDIRPLUS;
+	} else {
+		server->rpc_ops = &nfs_v2_clientops;
+	}
+#else
+	server->rpc_ops = &nfs_v2_clientops;
+#endif
+
+	/* Fill in pseudoflavor for mount version < 5 */
+	if (!(data->flags & NFS_MOUNT_SECFLAVOUR))
+		data->pseudoflavor = RPC_AUTH_UNIX;
+	authflavor = data->pseudoflavor;	/* save for sb_init() */
+	/* XXX maybe we want to add a server->pseudoflavor field */
+
+	/* Create RPC client handles */
+	server->client = nfs_create_client(server, data);
+	if (IS_ERR(server->client))
+		return PTR_ERR(server->client);
+	/* RFC 2623, sec 2.3.2 */
+	if (authflavor != RPC_AUTH_UNIX) {
+		struct rpc_auth *auth;
+
+		server->client_sys = rpc_clone_client(server->client);
+		if (IS_ERR(server->client_sys))
+			return PTR_ERR(server->client_sys);
+		auth = rpcauth_create(RPC_AUTH_UNIX, server->client_sys);
+		if (IS_ERR(auth))
+			return PTR_ERR(auth);
+	} else {
+		atomic_inc(&server->client->cl_count);
+		server->client_sys = server->client;
+	}
+	if (server->flags & NFS_MOUNT_VER3) {
+#ifdef CONFIG_NFS_V3_ACL
+		if (!(server->flags & NFS_MOUNT_NOACL)) {
+			server->client_acl = rpc_bind_new_program(server->client, &nfsacl_program, 3);
+			/* No errors! Assume that Sun nfsacls are supported */
+			if (!IS_ERR(server->client_acl))
+				server->caps |= NFS_CAP_ACLS;
+		}
+#else
+		server->flags &= ~NFS_MOUNT_NOACL;
+#endif /* CONFIG_NFS_V3_ACL */
+		/*
+		 * The VFS shouldn't apply the umask to mode bits. We will
+		 * do so ourselves when necessary.
+		 */
+		sb->s_flags |= MS_POSIXACL;
+		if (server->namelen == 0 || server->namelen > NFS3_MAXNAMLEN)
+			server->namelen = NFS3_MAXNAMLEN;
+		sb->s_time_gran = 1;
+	} else {
+		if (server->namelen == 0 || server->namelen > NFS2_MAXNAMLEN)
+			server->namelen = NFS2_MAXNAMLEN;
+	}
+
+	sb->s_op = &nfs_sops;
+	return nfs_sb_init(sb, authflavor);
+}
+
+static int nfs_set_super(struct super_block *s, void *data)
+{
+	s->s_fs_info = data;
+	return set_anon_super(s, data);
+}
+
+static int nfs_compare_super(struct super_block *sb, void *data)
+{
+	struct nfs_server *server = data;
+	struct nfs_server *old = NFS_SB(sb);
+
+	if (old->addr.sin_addr.s_addr != server->addr.sin_addr.s_addr)
+		return 0;
+	if (old->addr.sin_port != server->addr.sin_port)
+		return 0;
+	return !nfs_compare_fh(&old->fh, &server->fh);
+}
+
+static struct super_block *nfs_get_sb(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *raw_data)
+{
+	int error;
+	struct nfs_server *server = NULL;
+	struct super_block *s;
+	struct nfs_fh *root;
+	struct nfs_mount_data *data = raw_data;
+
+	s = ERR_PTR(-EINVAL);
+	if (data == NULL) {
+		dprintk("%s: missing data argument\n", __FUNCTION__);
+		goto out_err;
+	}
+	if (data->version <= 0 || data->version > NFS_MOUNT_VERSION) {
+		dprintk("%s: bad mount version\n", __FUNCTION__);
+		goto out_err;
+	}
+	switch (data->version) {
+		case 1:
+			data->namlen = 0;
+		case 2:
+			data->bsize  = 0;
+		case 3:
+			if (data->flags & NFS_MOUNT_VER3) {
+				dprintk("%s: mount structure version %d does not support NFSv3\n",
+						__FUNCTION__,
+						data->version);
+				goto out_err;
+			}
+			data->root.size = NFS2_FHSIZE;
+			memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
+		case 4:
+			if (data->flags & NFS_MOUNT_SECFLAVOUR) {
+				dprintk("%s: mount structure version %d does not support strong security\n",
+						__FUNCTION__,
+						data->version);
+				goto out_err;
+			}
+		case 5:
+			memset(data->context, 0, sizeof(data->context));
+	}
+#ifndef CONFIG_NFS_V3
+	/* If NFSv3 is not compiled in, return -EPROTONOSUPPORT */
+	s = ERR_PTR(-EPROTONOSUPPORT);
+	if (data->flags & NFS_MOUNT_VER3) {
+		dprintk("%s: NFSv3 not compiled into kernel\n", __FUNCTION__);
+		goto out_err;
+	}
+#endif /* CONFIG_NFS_V3 */
+
+	s = ERR_PTR(-ENOMEM);
+	server = kzalloc(sizeof(struct nfs_server), GFP_KERNEL);
+	if (!server)
+		goto out_err;
+	/* Zero out the NFS state stuff */
+	init_nfsv4_state(server);
+	server->client = server->client_sys = server->client_acl = ERR_PTR(-EINVAL);
+
+	root = &server->fh;
+	if (data->flags & NFS_MOUNT_VER3)
+		root->size = data->root.size;
+	else
+		root->size = NFS2_FHSIZE;
+	s = ERR_PTR(-EINVAL);
+	if (root->size > sizeof(root->data)) {
+		dprintk("%s: invalid root filehandle\n", __FUNCTION__);
+		goto out_err;
+	}
+	memcpy(root->data, data->root.data, root->size);
+
+	/* We now require that the mount process passes the remote address */
+	memcpy(&server->addr, &data->addr, sizeof(server->addr));
+	if (server->addr.sin_addr.s_addr == INADDR_ANY) {
+		dprintk("%s: mount program didn't pass remote address!\n",
+				__FUNCTION__);
+		goto out_err;
+	}
+
+	/* Fire up rpciod if not yet running */
+	s = ERR_PTR(rpciod_up());
+	if (IS_ERR(s)) {
+		dprintk("%s: couldn't start rpciod! Error = %ld\n",
+				__FUNCTION__, PTR_ERR(s));
+		goto out_err;
+	}
+
+	s = sget(fs_type, nfs_compare_super, nfs_set_super, server);
+	if (IS_ERR(s) || s->s_root)
+		goto out_rpciod_down;
+
+	s->s_flags = flags;
+
+	error = nfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
+	if (error) {
+		up_write(&s->s_umount);
+		deactivate_super(s);
+		return ERR_PTR(error);
+	}
+	s->s_flags |= MS_ACTIVE;
+	return s;
+out_rpciod_down:
+	rpciod_down();
+out_err:
+	kfree(server);
+	return s;
+}
+
+static void nfs_kill_super(struct super_block *s)
+{
+	struct nfs_server *server = NFS_SB(s);
+
+	kill_anon_super(s);
+
+	if (!IS_ERR(server->client))
+		rpc_shutdown_client(server->client);
+	if (!IS_ERR(server->client_sys))
+		rpc_shutdown_client(server->client_sys);
+	if (!IS_ERR(server->client_acl))
+		rpc_shutdown_client(server->client_acl);
+
+	if (!(server->flags & NFS_MOUNT_NONLM))
+		lockd_down();	/* release rpc.lockd */
+
+	rpciod_down();		/* release rpciod */
+
+	nfs_free_iostats(server->io_stats);
+	kfree(server->hostname);
+	kfree(server);
+	nfs_release_automount_timer();
+}
+
+static struct super_block *nfs_clone_sb(struct nfs_server *server, struct nfs_clone_mount *data)
+{
+	struct super_block *sb;
+
+	server->fsid = data->fattr->fsid;
+	nfs_copy_fh(&server->fh, data->fh);
+	sb = sget(&nfs_fs_type, nfs_compare_super, nfs_set_super, server);
+	if (!IS_ERR(sb) && sb->s_root == NULL && !(server->flags & NFS_MOUNT_NONLM))
+		lockd_up();
+	return sb;
+}
+
+static struct super_block *nfs_clone_nfs_sb(struct file_system_type *fs_type,
+		int flags, const char *dev_name, void *raw_data)
+{
+	struct nfs_clone_mount *data = raw_data;
+	return nfs_clone_generic_sb(data, nfs_clone_sb, nfs_clone_server);
+}
+
+#ifdef CONFIG_NFS_V4
+static struct rpc_clnt *nfs4_create_client(struct nfs_server *server,
+	struct rpc_timeout *timeparms, int proto, rpc_authflavor_t flavor)
+{
+	struct nfs4_client *clp;
+	struct rpc_xprt *xprt = NULL;
+	struct rpc_clnt *clnt = NULL;
+	int err = -EIO;
+
+	clp = nfs4_get_client(&server->addr.sin_addr);
+	if (!clp) {
+		dprintk("%s: failed to create NFS4 client.\n", __FUNCTION__);
+		return ERR_PTR(err);
+	}
+
+	/* Now create transport and client */
+	down_write(&clp->cl_sem);
+	if (IS_ERR(clp->cl_rpcclient)) {
+		xprt = xprt_create_proto(proto, &server->addr, timeparms);
+		if (IS_ERR(xprt)) {
+			up_write(&clp->cl_sem);
+			err = PTR_ERR(xprt);
+			dprintk("%s: cannot create RPC transport. Error = %d\n",
+					__FUNCTION__, err);
+			goto out_fail;
+		}
+		/* Bind to a reserved port! */
+		xprt->resvport = 1;
+		clnt = rpc_create_client(xprt, server->hostname, &nfs_program,
+				server->rpc_ops->version, flavor);
+		if (IS_ERR(clnt)) {
+			up_write(&clp->cl_sem);
+			err = PTR_ERR(clnt);
+			dprintk("%s: cannot create RPC client. Error = %d\n",
+					__FUNCTION__, err);
+			goto out_fail;
+		}
+		clnt->cl_intr     = 1;
+		clnt->cl_softrtry = 1;
+		clp->cl_rpcclient = clnt;
+		memcpy(clp->cl_ipaddr, server->ip_addr, sizeof(clp->cl_ipaddr));
+		nfs_idmap_new(clp);
+	}
+	list_add_tail(&server->nfs4_siblings, &clp->cl_superblocks);
+	clnt = rpc_clone_client(clp->cl_rpcclient);
+	if (!IS_ERR(clnt))
+		server->nfs4_state = clp;
+	up_write(&clp->cl_sem);
+	clp = NULL;
+
+	if (IS_ERR(clnt)) {
+		dprintk("%s: cannot create RPC client. Error = %d\n",
+				__FUNCTION__, err);
+		return clnt;
+	}
+
+	if (server->nfs4_state->cl_idmap == NULL) {
+		dprintk("%s: failed to create idmapper.\n", __FUNCTION__);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	if (clnt->cl_auth->au_flavor != flavor) {
+		struct rpc_auth *auth;
+
+		auth = rpcauth_create(flavor, clnt);
+		if (IS_ERR(auth)) {
+			dprintk("%s: couldn't create credcache!\n", __FUNCTION__);
+			return (struct rpc_clnt *)auth;
+		}
+	}
+	return clnt;
+
+ out_fail:
+	if (clp)
+		nfs4_put_client(clp);
+	return ERR_PTR(err);
+}
+
+/*
+ * Set up an NFS4 superblock
+ */
+static int nfs4_fill_super(struct super_block *sb, struct nfs4_mount_data *data, int silent)
+{
+	struct nfs_server *server;
+	struct rpc_timeout timeparms;
+	rpc_authflavor_t authflavour;
+	int err = -EIO;
+
+	sb->s_blocksize_bits = 0;
+	sb->s_blocksize = 0;
+	server = NFS_SB(sb);
+	if (data->rsize != 0)
+		server->rsize = nfs_block_size(data->rsize, NULL);
+	if (data->wsize != 0)
+		server->wsize = nfs_block_size(data->wsize, NULL);
+	server->flags = data->flags & NFS_MOUNT_FLAGMASK;
+	server->caps = NFS_CAP_ATOMIC_OPEN;
+
+	server->acregmin = data->acregmin*HZ;
+	server->acregmax = data->acregmax*HZ;
+	server->acdirmin = data->acdirmin*HZ;
+	server->acdirmax = data->acdirmax*HZ;
+
+	server->rpc_ops = &nfs_v4_clientops;
+
+	nfs_init_timeout_values(&timeparms, data->proto, data->timeo, data->retrans);
+
+	server->retrans_timeo = timeparms.to_initval;
+	server->retrans_count = timeparms.to_retries;
+
+	/* Now create transport and client */
+	authflavour = RPC_AUTH_UNIX;
+	if (data->auth_flavourlen != 0) {
+		if (data->auth_flavourlen != 1) {
+			dprintk("%s: Invalid number of RPC auth flavours %d.\n",
+					__FUNCTION__, data->auth_flavourlen);
+			err = -EINVAL;
+			goto out_fail;
+		}
+		if (copy_from_user(&authflavour, data->auth_flavours, sizeof(authflavour))) {
+			err = -EFAULT;
+			goto out_fail;
+		}
+	}
+
+	server->client = nfs4_create_client(server, &timeparms, data->proto, authflavour);
+	if (IS_ERR(server->client)) {
+		err = PTR_ERR(server->client);
+			dprintk("%s: cannot create RPC client. Error = %d\n",
+					__FUNCTION__, err);
+			goto out_fail;
+	}
+
+	sb->s_time_gran = 1;
+
+	sb->s_op = &nfs4_sops;
+	err = nfs_sb_init(sb, authflavour);
+
+ out_fail:
+	return err;
+}
+
+static int nfs4_compare_super(struct super_block *sb, void *data)
+{
+	struct nfs_server *server = data;
+	struct nfs_server *old = NFS_SB(sb);
+
+	if (strcmp(server->hostname, old->hostname) != 0)
+		return 0;
+	if (strcmp(server->mnt_path, old->mnt_path) != 0)
+		return 0;
+	return 1;
+}
+
+static void *
+nfs_copy_user_string(char *dst, struct nfs_string *src, int maxlen)
+{
+	void *p = NULL;
+
+	if (!src->len)
+		return ERR_PTR(-EINVAL);
+	if (src->len < maxlen)
+		maxlen = src->len;
+	if (dst == NULL) {
+		p = dst = kmalloc(maxlen + 1, GFP_KERNEL);
+		if (p == NULL)
+			return ERR_PTR(-ENOMEM);
+	}
+	if (copy_from_user(dst, src->data, maxlen)) {
+		kfree(p);
+		return ERR_PTR(-EFAULT);
+	}
+	dst[maxlen] = '\0';
+	return dst;
+}
+
+static struct super_block *nfs4_get_sb(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *raw_data)
+{
+	int error;
+	struct nfs_server *server;
+	struct super_block *s;
+	struct nfs4_mount_data *data = raw_data;
+	void *p;
+
+	if (data == NULL) {
+		dprintk("%s: missing data argument\n", __FUNCTION__);
+		return ERR_PTR(-EINVAL);
+	}
+	if (data->version <= 0 || data->version > NFS4_MOUNT_VERSION) {
+		dprintk("%s: bad mount version\n", __FUNCTION__);
+		return ERR_PTR(-EINVAL);
+	}
+
+	server = kzalloc(sizeof(struct nfs_server), GFP_KERNEL);
+	if (!server)
+		return ERR_PTR(-ENOMEM);
+	/* Zero out the NFS state stuff */
+	init_nfsv4_state(server);
+	server->client = server->client_sys = server->client_acl = ERR_PTR(-EINVAL);
+
+	p = nfs_copy_user_string(NULL, &data->hostname, 256);
+	if (IS_ERR(p))
+		goto out_err;
+	server->hostname = p;
+
+	p = nfs_copy_user_string(NULL, &data->mnt_path, 1024);
+	if (IS_ERR(p))
+		goto out_err;
+	server->mnt_path = p;
+
+	p = nfs_copy_user_string(server->ip_addr, &data->client_addr,
+			sizeof(server->ip_addr) - 1);
+	if (IS_ERR(p))
+		goto out_err;
+
+	/* We now require that the mount process passes the remote address */
+	if (data->host_addrlen != sizeof(server->addr)) {
+		s = ERR_PTR(-EINVAL);
+		goto out_free;
+	}
+	if (copy_from_user(&server->addr, data->host_addr, sizeof(server->addr))) {
+		s = ERR_PTR(-EFAULT);
+		goto out_free;
+	}
+	if (server->addr.sin_family != AF_INET ||
+	    server->addr.sin_addr.s_addr == INADDR_ANY) {
+		dprintk("%s: mount program didn't pass remote IP address!\n",
+				__FUNCTION__);
+		s = ERR_PTR(-EINVAL);
+		goto out_free;
+	}
+
+	/* Fire up rpciod if not yet running */
+	s = ERR_PTR(rpciod_up());
+	if (IS_ERR(s)) {
+		dprintk("%s: couldn't start rpciod! Error = %ld\n",
+				__FUNCTION__, PTR_ERR(s));
+		goto out_free;
+	}
+
+	s = sget(fs_type, nfs4_compare_super, nfs_set_super, server);
+
+	if (IS_ERR(s) || s->s_root)
+		goto out_free;
+
+	s->s_flags = flags;
+
+	error = nfs4_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
+	if (error) {
+		up_write(&s->s_umount);
+		deactivate_super(s);
+		return ERR_PTR(error);
+	}
+	s->s_flags |= MS_ACTIVE;
+	return s;
+out_err:
+	s = (struct super_block *)p;
+out_free:
+	kfree(server->mnt_path);
+	kfree(server->hostname);
+	kfree(server);
+	return s;
+}
+
+static void nfs4_kill_super(struct super_block *sb)
+{
+	struct nfs_server *server = NFS_SB(sb);
+
+	nfs_return_all_delegations(sb);
+	kill_anon_super(sb);
+
+	nfs4_renewd_prepare_shutdown(server);
+
+	if (server->client != NULL && !IS_ERR(server->client))
+		rpc_shutdown_client(server->client);
+
+	destroy_nfsv4_state(server);
+
+	rpciod_down();
+
+	nfs_free_iostats(server->io_stats);
+	kfree(server->hostname);
+	kfree(server);
+	nfs_release_automount_timer();
+}
+
+/*
+ * Constructs the SERVER-side path
+ */
+static inline char *nfs4_dup_path(const struct dentry *dentry)
+{
+	char *page = (char *) __get_free_page(GFP_USER);
+	char *path;
+
+	path = nfs4_path(dentry, page, PAGE_SIZE);
+	if (!IS_ERR(path)) {
+		int len = PAGE_SIZE + page - path;
+		char *tmp = path;
+
+		path = kmalloc(len, GFP_KERNEL);
+		if (path)
+			memcpy(path, tmp, len);
+		else
+			path = ERR_PTR(-ENOMEM);
+	}
+	free_page((unsigned long)page);
+	return path;
+}
+
+static struct super_block *nfs4_clone_sb(struct nfs_server *server, struct nfs_clone_mount *data)
+{
+	const struct dentry *dentry = data->dentry;
+	struct nfs4_client *clp = server->nfs4_state;
+	struct super_block *sb;
+
+	server->fsid = data->fattr->fsid;
+	nfs_copy_fh(&server->fh, data->fh);
+	server->mnt_path = nfs4_dup_path(dentry);
+	if (IS_ERR(server->mnt_path)) {
+		sb = (struct super_block *)server->mnt_path;
+		goto err;
+	}
+	sb = sget(&nfs4_fs_type, nfs4_compare_super, nfs_set_super, server);
+	if (IS_ERR(sb) || sb->s_root)
+		goto free_path;
+	nfs4_server_capabilities(server, &server->fh);
+
+	down_write(&clp->cl_sem);
+	atomic_inc(&clp->cl_count);
+	list_add_tail(&server->nfs4_siblings, &clp->cl_superblocks);
+	up_write(&clp->cl_sem);
+	return sb;
+free_path:
+	kfree(server->mnt_path);
+err:
+	server->mnt_path = NULL;
+	return sb;
+}
+
+static struct super_block *nfs_clone_nfs4_sb(struct file_system_type *fs_type,
+		int flags, const char *dev_name, void *raw_data)
+{
+	struct nfs_clone_mount *data = raw_data;
+	return nfs_clone_generic_sb(data, nfs4_clone_sb, nfs_clone_server);
+}
+
+static struct super_block *nfs4_referral_sb(struct nfs_server *server, struct nfs_clone_mount *data)
+{
+	struct super_block *sb = ERR_PTR(-ENOMEM);
+	int len;
+
+	len = strlen(data->mnt_path) + 1;
+	server->mnt_path = kmalloc(len, GFP_KERNEL);
+	if (server->mnt_path == NULL)
+		goto err;
+	memcpy(server->mnt_path, data->mnt_path, len);
+	memcpy(&server->addr, data->addr, sizeof(struct sockaddr_in));
+
+	sb = sget(&nfs4_fs_type, nfs4_compare_super, nfs_set_super, server);
+	if (IS_ERR(sb) || sb->s_root)
+		goto free_path;
+	return sb;
+free_path:
+	kfree(server->mnt_path);
+err:
+	server->mnt_path = NULL;
+	return sb;
+}
+
+static struct nfs_server *nfs4_referral_server(struct super_block *sb, struct nfs_clone_mount *data)
+{
+	struct nfs_server *server = NFS_SB(sb);
+	struct rpc_timeout timeparms;
+	int proto, timeo, retrans;
+	void *err;
+
+	proto = IPPROTO_TCP;
+	/* Since we are following a referral and there may be alternatives,
+	   set the timeouts and retries to low values */
+	timeo = 2;
+	retrans = 1;
+	nfs_init_timeout_values(&timeparms, proto, timeo, retrans);
+
+	server->client = nfs4_create_client(server, &timeparms, proto, data->authflavor);
+	if (IS_ERR((err = server->client)))
+		goto out_err;
+
+	sb->s_time_gran = 1;
+	sb->s_op = &nfs4_sops;
+	err = ERR_PTR(nfs_sb_init(sb, data->authflavor));
+	if (!IS_ERR(err))
+		return server;
+out_err:
+	return (struct nfs_server *)err;
+}
+
+static struct super_block *nfs_referral_nfs4_sb(struct file_system_type *fs_type,
+		int flags, const char *dev_name, void *raw_data)
+{
+	struct nfs_clone_mount *data = raw_data;
+	return nfs_clone_generic_sb(data, nfs4_referral_sb, nfs4_referral_server);
+}
+
+#endif