/*

   * Syscall interface to knfsd.
   *
   * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   */

  #include <linux/slab.h>

  #include <linux/namei.h>

  #include <linux/ctype.h>

  #include <linux/sunrpc/svcsock.h>

  #include <linux/lockd/lockd.h>

  #include <linux/sunrpc/addr.h>

  #include <linux/sunrpc/gss_api.h>

  #include <linux/sunrpc/gss_krb5_enctypes.h>

  #include <linux/sunrpc/rpc_pipe_fs.h>

  #include <linux/module.h>

  #include "idmap.h"

  #include "nfsd.h"
  #include "cache.h"

  #include "state.h"

  #include "netns.h"

  #include "pnfs.h"

  /*

   *	We have a single directory with several nodes in it.

   */
  enum {
  	NFSD_Root = 1,

  	NFSD_List,

  	NFSD_Export_features,

  	NFSD_Fh,

  	NFSD_FO_UnlockIP,

  	NFSD_FO_UnlockFS,

  	NFSD_Threads,

  	NFSD_Pool_Threads,

  	NFSD_Pool_Stats,

  	NFSD_Reply_Cache_Stats,

  	NFSD_Versions,

  	NFSD_Ports,

  	NFSD_MaxBlkSize,

  	NFSD_MaxConnections,

  	NFSD_SupportedEnctypes,

  	/*
  	 * The below MUST come last.  Otherwise we leave a hole in nfsd_files[]
  	 * with !CONFIG_NFSD_V4 and simple_fill_super() goes oops
  	 */
  #ifdef CONFIG_NFSD_V4

  	NFSD_Leasetime,

  	NFSD_Gracetime,

  	NFSD_RecoveryDir,

  	NFSD_V4EndGrace,

  #endif

  };
  
  /*
   * write() for these nodes.
   */

  static ssize_t write_filehandle(struct file *file, char *buf, size_t size);

  static ssize_t write_unlock_ip(struct file *file, char *buf, size_t size);
  static ssize_t write_unlock_fs(struct file *file, char *buf, size_t size);

  static ssize_t write_threads(struct file *file, char *buf, size_t size);

  static ssize_t write_pool_threads(struct file *file, char *buf, size_t size);

  static ssize_t write_versions(struct file *file, char *buf, size_t size);

  static ssize_t write_ports(struct file *file, char *buf, size_t size);

  static ssize_t write_maxblksize(struct file *file, char *buf, size_t size);

  static ssize_t write_maxconn(struct file *file, char *buf, size_t size);

  #ifdef CONFIG_NFSD_V4

  static ssize_t write_leasetime(struct file *file, char *buf, size_t size);

  static ssize_t write_gracetime(struct file *file, char *buf, size_t size);

  static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);

  static ssize_t write_v4_end_grace(struct file *file, char *buf, size_t size);

  #endif

  
  static ssize_t (*write_op[])(struct file *, char *, size_t) = {

  	[NFSD_Fh] = write_filehandle,

  	[NFSD_FO_UnlockIP] = write_unlock_ip,
  	[NFSD_FO_UnlockFS] = write_unlock_fs,

  	[NFSD_Threads] = write_threads,

  	[NFSD_Pool_Threads] = write_pool_threads,

  	[NFSD_Versions] = write_versions,

  	[NFSD_Ports] = write_ports,

  	[NFSD_MaxBlkSize] = write_maxblksize,

  	[NFSD_MaxConnections] = write_maxconn,

  #ifdef CONFIG_NFSD_V4

  	[NFSD_Leasetime] = write_leasetime,

  	[NFSD_Gracetime] = write_gracetime,

  	[NFSD_RecoveryDir] = write_recoverydir,

  	[NFSD_V4EndGrace] = write_v4_end_grace,

  #endif

  };
  
  static ssize_t nfsctl_transaction_write(struct file *file, const char __user *buf, size_t size, loff_t *pos)
  {

  	ino_t ino =  file_inode(file)->i_ino;

  	char *data;
  	ssize_t rv;

  	if (ino >= ARRAY_SIZE(write_op) || !write_op[ino])

  		return -EINVAL;
  
  	data = simple_transaction_get(file, buf, size);
  	if (IS_ERR(data))
  		return PTR_ERR(data);
  
  	rv =  write_op[ino](file, data, size);

  	if (rv >= 0) {

  		simple_transaction_set(file, rv);
  		rv = size;
  	}
  	return rv;
  }

  static ssize_t nfsctl_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
  {
  	if (! file->private_data) {
  		/* An attempt to read a transaction file without writing
  		 * causes a 0-byte write so that the file can return
  		 * state information
  		 */
  		ssize_t rv = nfsctl_transaction_write(file, buf, 0, pos);
  		if (rv < 0)
  			return rv;
  	}
  	return simple_transaction_read(file, buf, size, pos);
  }

  static const struct file_operations transaction_ops = {

  	.write		= nfsctl_transaction_write,

  	.read		= nfsctl_transaction_read,

  	.release	= simple_transaction_release,

  	.llseek		= default_llseek,

  };

  static int exports_net_open(struct net *net, struct file *file)

  {

  	int err;
  	struct seq_file *seq;

  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

  
  	err = seq_open(file, &nfs_exports_op);
  	if (err)
  		return err;
  
  	seq = file->private_data;

  	seq->private = nn->svc_export_cache;

  	return 0;

  }

  static int exports_proc_open(struct inode *inode, struct file *file)
  {
  	return exports_net_open(current->nsproxy->net_ns, file);
  }
  
  static const struct file_operations exports_proc_operations = {
  	.open		= exports_proc_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= seq_release,

  };
  
  static int exports_nfsd_open(struct inode *inode, struct file *file)
  {
  	return exports_net_open(inode->i_sb->s_fs_info, file);
  }
  
  static const struct file_operations exports_nfsd_operations = {
  	.open		= exports_nfsd_open,

  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= seq_release,
  };

  static int export_features_show(struct seq_file *m, void *v)
  {
  	seq_printf(m, "0x%x 0x%x
  ", NFSEXP_ALLFLAGS, NFSEXP_SECINFO_FLAGS);
  	return 0;
  }
  
  static int export_features_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, export_features_show, NULL);
  }

  static const struct file_operations export_features_operations = {

  	.open		= export_features_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };

  #if defined(CONFIG_SUNRPC_GSS) || defined(CONFIG_SUNRPC_GSS_MODULE)

  static int supported_enctypes_show(struct seq_file *m, void *v)
  {

  	seq_printf(m, KRB5_SUPPORTED_ENCTYPES);

  	return 0;
  }
  
  static int supported_enctypes_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, supported_enctypes_show, NULL);
  }

  static const struct file_operations supported_enctypes_ops = {

  	.open		= supported_enctypes_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };

  #endif /* CONFIG_SUNRPC_GSS or CONFIG_SUNRPC_GSS_MODULE */

  static const struct file_operations pool_stats_operations = {

  	.open		= nfsd_pool_stats_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,

  	.release	= nfsd_pool_stats_release,

  };

  static struct file_operations reply_cache_stats_operations = {
  	.open		= nfsd_reply_cache_stats_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };

  /*----------------------------------------------------------------------------*/
  /*
   * payload - write methods

   */

  static inline struct net *netns(struct file *file)
  {
  	return file_inode(file)->i_sb->s_fs_info;
  }

  /**
   * write_unlock_ip - Release all locks used by a client
   *
   * Experimental.
   *
   * Input:
   *			buf:	'
  '-terminated C string containing a

   *				presentation format IP address

   *			size:	length of C string in @buf
   * Output:
   *	On success:	returns zero if all specified locks were released;
   *			returns one if one or more locks were not released
   *	On error:	return code is negative errno value

   */

  static ssize_t write_unlock_ip(struct file *file, char *buf, size_t size)

  {

  	struct sockaddr_storage address;
  	struct sockaddr *sap = (struct sockaddr *)&address;
  	size_t salen = sizeof(address);

  	char *fo_path;

  	struct net *net = netns(file);

  
  	/* sanity check */
  	if (size == 0)
  		return -EINVAL;
  
  	if (buf[size-1] != '
  ')
  		return -EINVAL;
  
  	fo_path = buf;
  	if (qword_get(&buf, fo_path, size) < 0)
  		return -EINVAL;

  	if (rpc_pton(net, fo_path, size, sap, salen) == 0)

  		return -EINVAL;

  	return nlmsvc_unlock_all_by_ip(sap);

  }

  /**
   * write_unlock_fs - Release all locks on a local file system
   *
   * Experimental.
   *
   * Input:
   *			buf:	'
  '-terminated C string containing the
   *				absolute pathname of a local file system
   *			size:	length of C string in @buf
   * Output:
   *	On success:	returns zero if all specified locks were released;
   *			returns one if one or more locks were not released
   *	On error:	return code is negative errno value
   */

  static ssize_t write_unlock_fs(struct file *file, char *buf, size_t size)

  {

  	struct path path;

  	char *fo_path;
  	int error;
  
  	/* sanity check */
  	if (size == 0)
  		return -EINVAL;
  
  	if (buf[size-1] != '
  ')
  		return -EINVAL;
  
  	fo_path = buf;
  	if (qword_get(&buf, fo_path, size) < 0)
  		return -EINVAL;

  	error = kern_path(fo_path, 0, &path);

  	if (error)
  		return error;

  	/*
  	 * XXX: Needs better sanity checking.  Otherwise we could end up
  	 * releasing locks on the wrong file system.
  	 *
  	 * For example:
  	 * 1.  Does the path refer to a directory?
  	 * 2.  Is that directory a mount point, or
  	 * 3.  Is that directory the root of an exported file system?
  	 */

  	error = nlmsvc_unlock_all_by_sb(path.dentry->d_sb);

  	path_put(&path);

  	return error;
  }

  /**
   * write_filehandle - Get a variable-length NFS file handle by path
   *
   * On input, the buffer contains a '
  '-terminated C string comprised of
   * three alphanumeric words separated by whitespace.  The string may
   * contain escape sequences.
   *
   * Input:
   *			buf:
   *				domain:		client domain name
   *				path:		export pathname
   *				maxsize:	numeric maximum size of
   *						@buf
   *			size:	length of C string in @buf
   * Output:
   *	On success:	passed-in buffer filled with '
  '-terminated C
   *			string containing a ASCII hex text version
   *			of the NFS file handle;
   *			return code is the size in bytes of the string
   *	On error:	return code is negative errno value
   */

  static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
  {

  	char *dname, *path;

  	int uninitialized_var(maxsize);

  	char *mesg = buf;
  	int len;
  	struct auth_domain *dom;
  	struct knfsd_fh fh;

  	if (size == 0)
  		return -EINVAL;

  	if (buf[size-1] != '
  ')
  		return -EINVAL;
  	buf[size-1] = 0;
  
  	dname = mesg;
  	len = qword_get(&mesg, dname, size);

  	if (len <= 0)
  		return -EINVAL;

  	
  	path = dname+len+1;
  	len = qword_get(&mesg, path, size);

  	if (len <= 0)
  		return -EINVAL;

  
  	len = get_int(&mesg, &maxsize);
  	if (len)
  		return len;
  
  	if (maxsize < NFS_FHSIZE)
  		return -EINVAL;

  	maxsize = min(maxsize, NFS3_FHSIZE);

  
  	if (qword_get(&mesg, mesg, size)>0)
  		return -EINVAL;
  
  	/* we have all the words, they are in buf.. */
  	dom = unix_domain_find(dname);
  	if (!dom)
  		return -ENOMEM;

  	len = exp_rootfh(netns(file), dom, path, &fh,  maxsize);

  	auth_domain_put(dom);
  	if (len)
  		return len;
  	

  	mesg = buf;
  	len = SIMPLE_TRANSACTION_LIMIT;

  	qword_addhex(&mesg, &len, (char*)&fh.fh_base, fh.fh_size);
  	mesg[-1] = '
  ';
  	return mesg - buf;	
  }

  /**
   * write_threads - Start NFSD, or report the current number of running threads
   *
   * Input:
   *			buf:		ignored
   *			size:		zero
   * Output:
   *	On success:	passed-in buffer filled with '
  '-terminated C
   *			string numeric value representing the number of
   *			running NFSD threads;
   *			return code is the size in bytes of the string
   *	On error:	return code is zero
   *
   * OR
   *
   * Input:
   *			buf:		C string containing an unsigned
   *					integer value representing the
   *					number of NFSD threads to start
   *			size:		non-zero length of C string in @buf
   * Output:
   *	On success:	NFS service is started;
   *			passed-in buffer filled with '
  '-terminated C
   *			string numeric value representing the number of
   *			running NFSD threads;
   *			return code is the size in bytes of the string
   *	On error:	return code is zero or a negative errno value
   */

  static ssize_t write_threads(struct file *file, char *buf, size_t size)
  {

  	char *mesg = buf;
  	int rv;

  	struct net *net = netns(file);

  	if (size > 0) {
  		int newthreads;
  		rv = get_int(&mesg, &newthreads);
  		if (rv)
  			return rv;

  		if (newthreads < 0)

  			return -EINVAL;

  		rv = nfsd_svc(newthreads, net);

  		if (rv < 0)

  			return rv;

  	} else

  		rv = nfsd_nrthreads(net);

  	return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%d
  ", rv);

  }

  /**
   * write_pool_threads - Set or report the current number of threads per pool
   *
   * Input:
   *			buf:		ignored
   *			size:		zero
   *
   * OR
   *
   * Input:
   * 			buf:		C string containing whitespace-
   * 					separated unsigned integer values
   *					representing the number of NFSD
   *					threads to start in each pool
   *			size:		non-zero length of C string in @buf
   * Output:
   *	On success:	passed-in buffer filled with '
  '-terminated C
   *			string containing integer values representing the
   *			number of NFSD threads in each pool;
   *			return code is the size in bytes of the string
   *	On error:	return code is zero or a negative errno value
   */

  static ssize_t write_pool_threads(struct file *file, char *buf, size_t size)
  {
  	/* if size > 0, look for an array of number of threads per node
  	 * and apply them  then write out number of threads per node as reply
  	 */
  	char *mesg = buf;
  	int i;
  	int rv;
  	int len;

  	int npools;

  	int *nthreads;

  	struct net *net = netns(file);

  	mutex_lock(&nfsd_mutex);

  	npools = nfsd_nrpools(net);

  	if (npools == 0) {
  		/*
  		 * NFS is shut down.  The admin can start it by
  		 * writing to the threads file but NOT the pool_threads
  		 * file, sorry.  Report zero threads.
  		 */

  		mutex_unlock(&nfsd_mutex);

  		strcpy(buf, "0
  ");
  		return strlen(buf);
  	}
  
  	nthreads = kcalloc(npools, sizeof(int), GFP_KERNEL);

  	rv = -ENOMEM;

  	if (nthreads == NULL)

  		goto out_free;

  
  	if (size > 0) {
  		for (i = 0; i < npools; i++) {
  			rv = get_int(&mesg, &nthreads[i]);
  			if (rv == -ENOENT)
  				break;		/* fewer numbers than pools */
  			if (rv)
  				goto out_free;	/* syntax error */
  			rv = -EINVAL;
  			if (nthreads[i] < 0)
  				goto out_free;
  		}

  		rv = nfsd_set_nrthreads(i, nthreads, net);

  		if (rv)
  			goto out_free;
  	}

  	rv = nfsd_get_nrthreads(npools, nthreads, net);

  	if (rv)
  		goto out_free;
  
  	mesg = buf;
  	size = SIMPLE_TRANSACTION_LIMIT;
  	for (i = 0; i < npools && size > 0; i++) {
  		snprintf(mesg, size, "%d%c", nthreads[i], (i == npools-1 ? '
  ' : ' '));
  		len = strlen(mesg);
  		size -= len;
  		mesg += len;
  	}

  	rv = mesg - buf;

  out_free:
  	kfree(nthreads);

  	mutex_unlock(&nfsd_mutex);

  	return rv;
  }

  static ssize_t __write_versions(struct file *file, char *buf, size_t size)

  {

  	char *mesg = buf;

  	char *vers, *minorp, sign;

  	int len, num, remaining;

  	unsigned minor;

  	ssize_t tlen = 0;
  	char *sep;

  	struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id);

  
  	if (size>0) {

  		if (nn->nfsd_serv)

  			/* Cannot change versions without updating

  			 * nn->nfsd_serv->sv_xdrsize, and reallocing

  			 * rq_argp and rq_resp
  			 */

  			return -EBUSY;
  		if (buf[size-1] != '
  ')
  			return -EINVAL;
  		buf[size-1] = 0;
  
  		vers = mesg;
  		len = qword_get(&mesg, vers, size);
  		if (len <= 0) return -EINVAL;
  		do {
  			sign = *vers;
  			if (sign == '+' || sign == '-')

  				num = simple_strtol((vers+1), &minorp, 0);

  			else

  				num = simple_strtol(vers, &minorp, 0);
  			if (*minorp == '.') {

  				if (num != 4)

  					return -EINVAL;
  				minor = simple_strtoul(minorp+1, NULL, 0);
  				if (minor == 0)
  					return -EINVAL;
  				if (nfsd_minorversion(minor, sign == '-' ?
  						     NFSD_CLEAR : NFSD_SET) < 0)
  					return -EINVAL;
  				goto next;
  			}

  			switch(num) {
  			case 2:
  			case 3:
  			case 4:

  				nfsd_vers(num, sign == '-' ? NFSD_CLEAR : NFSD_SET);

  				break;
  			default:
  				return -EINVAL;
  			}

  		next:

  			vers += len + 1;

  		} while ((len = qword_get(&mesg, vers, size)) > 0);
  		/* If all get turned off, turn them back on, as
  		 * having no versions is BAD
  		 */

  		nfsd_reset_versions();

  	}

  	/* Now write current state into reply buffer */
  	len = 0;
  	sep = "";

  	remaining = SIMPLE_TRANSACTION_LIMIT;

  	for (num=2 ; num <= 4 ; num++)

  		if (nfsd_vers(num, NFSD_AVAIL)) {

  			len = snprintf(buf, remaining, "%s%c%d", sep,

  				       nfsd_vers(num, NFSD_TEST)?'+':'-',

  				       num);
  			sep = " ";

  			if (len >= remaining)

  				break;
  			remaining -= len;
  			buf += len;
  			tlen += len;

  		}

  	if (nfsd_vers(4, NFSD_AVAIL))

  		for (minor = 1; minor <= NFSD_SUPPORTED_MINOR_VERSION;
  		     minor++) {
  			len = snprintf(buf, remaining, " %c4.%u",

  					(nfsd_vers(4, NFSD_TEST) &&
  					 nfsd_minorversion(minor, NFSD_TEST)) ?
  						'+' : '-',
  					minor);

  			if (len >= remaining)

  				break;
  			remaining -= len;
  			buf += len;
  			tlen += len;
  		}
  
  	len = snprintf(buf, remaining, "
  ");

  	if (len >= remaining)

  		return -EINVAL;
  	return tlen + len;

  }

  /**
   * write_versions - Set or report the available NFS protocol versions
   *
   * Input:
   *			buf:		ignored
   *			size:		zero
   * Output:
   *	On success:	passed-in buffer filled with '
  '-terminated C
   *			string containing positive or negative integer
   *			values representing the current status of each
   *			protocol version;
   *			return code is the size in bytes of the string
   *	On error:	return code is zero or a negative errno value
   *
   * OR
   *
   * Input:
   * 			buf:		C string containing whitespace-
   * 					separated positive or negative
   * 					integer values representing NFS
   * 					protocol versions to enable ("+n")
   * 					or disable ("-n")
   *			size:		non-zero length of C string in @buf
   * Output:
   *	On success:	status of zero or more protocol versions has
   *			been updated; passed-in buffer filled with
   *			'
  '-terminated C string containing positive
   *			or negative integer values representing the
   *			current status of each protocol version;
   *			return code is the size in bytes of the string
   *	On error:	return code is zero or a negative errno value
   */

  static ssize_t write_versions(struct file *file, char *buf, size_t size)
  {
  	ssize_t rv;
  
  	mutex_lock(&nfsd_mutex);
  	rv = __write_versions(file, buf, size);
  	mutex_unlock(&nfsd_mutex);
  	return rv;
  }

  /*

   * Zero-length write.  Return a list of NFSD's current listener
   * transports.
   */

  static ssize_t __write_ports_names(char *buf, struct net *net)

  {

  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
  
  	if (nn->nfsd_serv == NULL)

  		return 0;

  	return svc_xprt_names(nn->nfsd_serv, buf, SIMPLE_TRANSACTION_LIMIT);

  }
  
  /*

   * A single 'fd' number was written, in which case it must be for
   * a socket of a supported family/protocol, and we use it as an
   * nfsd listener.
   */

  static ssize_t __write_ports_addfd(char *buf, struct net *net)

  {
  	char *mesg = buf;
  	int fd, err;

  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

  
  	err = get_int(&mesg, &fd);
  	if (err != 0 || fd < 0)
  		return -EINVAL;

  	if (svc_alien_sock(net, fd)) {
  		printk(KERN_ERR "%s: socket net is different to NFSd's one
  ", __func__);
  		return -EINVAL;
  	}

  	err = nfsd_create_serv(net);

  	if (err != 0)
  		return err;

  	err = svc_addsock(nn->nfsd_serv, fd, buf, SIMPLE_TRANSACTION_LIMIT);

  	if (err < 0) {

  		nfsd_destroy(net);

  		return err;
  	}

  	/* Decrease the count, but don't shut down the service */

  	nn->nfsd_serv->sv_nrthreads--;

  	return err;

  }
  
  /*

   * A transport listener is added by writing it's transport name and
   * a port number.
   */

  static ssize_t __write_ports_addxprt(char *buf, struct net *net)

  {
  	char transport[16];

  	struct svc_xprt *xprt;

  	int port, err;

  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

  	if (sscanf(buf, "%15s %5u", transport, &port) != 2)

  		return -EINVAL;

  	if (port < 1 || port > USHRT_MAX)

  		return -EINVAL;

  	err = nfsd_create_serv(net);

  	if (err != 0)
  		return err;

  	err = svc_create_xprt(nn->nfsd_serv, transport, net,

  				PF_INET, port, SVC_SOCK_ANONYMOUS);

  	if (err < 0)

  		goto out_err;

  	err = svc_create_xprt(nn->nfsd_serv, transport, net,

  				PF_INET6, port, SVC_SOCK_ANONYMOUS);
  	if (err < 0 && err != -EAFNOSUPPORT)
  		goto out_close;

  
  	/* Decrease the count, but don't shut down the service */

  	nn->nfsd_serv->sv_nrthreads--;

  	return 0;

  out_close:

  	xprt = svc_find_xprt(nn->nfsd_serv, transport, net, PF_INET, port);

  	if (xprt != NULL) {
  		svc_close_xprt(xprt);
  		svc_xprt_put(xprt);
  	}
  out_err:

  	nfsd_destroy(net);

  	return err;

  }

  static ssize_t __write_ports(struct file *file, char *buf, size_t size,
  			     struct net *net)

  {

  	if (size == 0)

  		return __write_ports_names(buf, net);

  
  	if (isdigit(buf[0]))

  		return __write_ports_addfd(buf, net);

  	if (isalpha(buf[0]))

  		return __write_ports_addxprt(buf, net);

  	return -EINVAL;

  }

  /**
   * write_ports - Pass a socket file descriptor or transport name to listen on
   *
   * Input:
   *			buf:		ignored
   *			size:		zero
   * Output:
   *	On success:	passed-in buffer filled with a '
  '-terminated C
   *			string containing a whitespace-separated list of
   *			named NFSD listeners;
   *			return code is the size in bytes of the string
   *	On error:	return code is zero or a negative errno value
   *
   * OR
   *
   * Input:
   *			buf:		C string containing an unsigned
   *					integer value representing a bound
   *					but unconnected socket that is to be

   *					used as an NFSD listener; listen(3)
   *					must be called for a SOCK_STREAM
   *					socket, otherwise it is ignored

   *			size:		non-zero length of C string in @buf
   * Output:
   *	On success:	NFS service is started;
   *			passed-in buffer filled with a '
  '-terminated C
   *			string containing a unique alphanumeric name of
   *			the listener;
   *			return code is the size in bytes of the string
   *	On error:	return code is a negative errno value
   *
   * OR
   *
   * Input:

   *			buf:		C string containing a transport
   *					name and an unsigned integer value
   *					representing the port to listen on,
   *					separated by whitespace
   *			size:		non-zero length of C string in @buf
   * Output:
   *	On success:	returns zero; NFS service is started
   *	On error:	return code is a negative errno value

   */

  static ssize_t write_ports(struct file *file, char *buf, size_t size)
  {
  	ssize_t rv;

  	mutex_lock(&nfsd_mutex);

  	rv = __write_ports(file, buf, size, netns(file));

  	mutex_unlock(&nfsd_mutex);
  	return rv;
  }

  int nfsd_max_blksize;

  /**
   * write_maxblksize - Set or report the current NFS blksize
   *
   * Input:
   *			buf:		ignored
   *			size:		zero
   *
   * OR
   *
   * Input:
   * 			buf:		C string containing an unsigned
   * 					integer value representing the new
   * 					NFS blksize
   *			size:		non-zero length of C string in @buf
   * Output:
   *	On success:	passed-in buffer filled with '
  '-terminated C string
   *			containing numeric value of the current NFS blksize
   *			setting;
   *			return code is the size in bytes of the string
   *	On error:	return code is zero or a negative errno value
   */

  static ssize_t write_maxblksize(struct file *file, char *buf, size_t size)
  {
  	char *mesg = buf;

  	struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id);

  	if (size > 0) {
  		int bsize;
  		int rv = get_int(&mesg, &bsize);
  		if (rv)
  			return rv;
  		/* force bsize into allowed range and
  		 * required alignment.
  		 */

  		bsize = max_t(int, bsize, 1024);
  		bsize = min_t(int, bsize, NFSSVC_MAXBLKSIZE);

  		bsize &= ~(1024-1);

  		mutex_lock(&nfsd_mutex);

  		if (nn->nfsd_serv) {

  			mutex_unlock(&nfsd_mutex);

  			return -EBUSY;
  		}
  		nfsd_max_blksize = bsize;

  		mutex_unlock(&nfsd_mutex);

  	}

  
  	return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%d
  ",
  							nfsd_max_blksize);

  }

  /**
   * write_maxconn - Set or report the current max number of connections
   *
   * Input:
   *			buf:		ignored
   *			size:		zero
   * OR
   *
   * Input:
   * 			buf:		C string containing an unsigned
   * 					integer value representing the new
   * 					number of max connections
   *			size:		non-zero length of C string in @buf
   * Output:
   *	On success:	passed-in buffer filled with '
  '-terminated C string
   *			containing numeric value of max_connections setting
   *			for this net namespace;
   *			return code is the size in bytes of the string
   *	On error:	return code is zero or a negative errno value
   */
  static ssize_t write_maxconn(struct file *file, char *buf, size_t size)
  {
  	char *mesg = buf;

  	struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id);

  	unsigned int maxconn = nn->max_connections;
  
  	if (size > 0) {
  		int rv = get_uint(&mesg, &maxconn);
  
  		if (rv)
  			return rv;
  		nn->max_connections = maxconn;
  	}
  
  	return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%u
  ", maxconn);
  }

  #ifdef CONFIG_NFSD_V4

  static ssize_t __nfsd4_write_time(struct file *file, char *buf, size_t size,
  				  time_t *time, struct nfsd_net *nn)

  {

  	char *mesg = buf;

  	int rv, i;

  
  	if (size > 0) {

  		if (nn->nfsd_serv)

  			return -EBUSY;

  		rv = get_int(&mesg, &i);

  		if (rv)
  			return rv;

  		/*
  		 * Some sanity checking.  We don't have a reason for
  		 * these particular numbers, but problems with the
  		 * extremes are:
  		 *	- Too short: the briefest network outage may
  		 *	  cause clients to lose all their locks.  Also,
  		 *	  the frequent polling may be wasteful.
  		 *	- Too long: do you really want reboot recovery
  		 *	  to take more than an hour?  Or to make other
  		 *	  clients wait an hour before being able to
  		 *	  revoke a dead client's locks?
  		 */

  		if (i < 10 || i > 3600)

  			return -EINVAL;

  		*time = i;

  	}

  	return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%ld
  ", *time);
  }

  static ssize_t nfsd4_write_time(struct file *file, char *buf, size_t size,
  				time_t *time, struct nfsd_net *nn)

  {
  	ssize_t rv;
  
  	mutex_lock(&nfsd_mutex);

  	rv = __nfsd4_write_time(file, buf, size, time, nn);

  	mutex_unlock(&nfsd_mutex);
  	return rv;

  }

  /**
   * write_leasetime - Set or report the current NFSv4 lease time
   *
   * Input:
   *			buf:		ignored
   *			size:		zero
   *
   * OR
   *
   * Input:
   *			buf:		C string containing an unsigned
   *					integer value representing the new
   *					NFSv4 lease expiry time
   *			size:		non-zero length of C string in @buf
   * Output:
   *	On success:	passed-in buffer filled with '
  '-terminated C
   *			string containing unsigned integer value of the
   *			current lease expiry time;
   *			return code is the size in bytes of the string
   *	On error:	return code is zero or a negative errno value
   */

  static ssize_t write_leasetime(struct file *file, char *buf, size_t size)
  {

  	struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id);

  	return nfsd4_write_time(file, buf, size, &nn->nfsd4_lease, nn);

  }

  /**
   * write_gracetime - Set or report current NFSv4 grace period time
   *
   * As above, but sets the time of the NFSv4 grace period.
   *
   * Note this should never be set to less than the *previous*
   * lease-period time, but we don't try to enforce this.  (In the common
   * case (a new boot), we don't know what the previous lease time was
   * anyway.)
   */
  static ssize_t write_gracetime(struct file *file, char *buf, size_t size)
  {

  	struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id);

  	return nfsd4_write_time(file, buf, size, &nn->nfsd4_grace, nn);

  }

  static ssize_t __write_recoverydir(struct file *file, char *buf, size_t size,
  				   struct nfsd_net *nn)

  {
  	char *mesg = buf;
  	char *recdir;
  	int len, status;

  	if (size > 0) {

  		if (nn->nfsd_serv)

  			return -EBUSY;
  		if (size > PATH_MAX || buf[size-1] != '
  ')
  			return -EINVAL;
  		buf[size-1] = 0;

  		recdir = mesg;
  		len = qword_get(&mesg, recdir, size);
  		if (len <= 0)
  			return -EINVAL;

  		status = nfs4_reset_recoverydir(recdir);

  		if (status)
  			return status;

  	}

  
  	return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%s
  ",
  							nfs4_recoverydir());

  }

  /**
   * write_recoverydir - Set or report the pathname of the recovery directory
   *
   * Input:
   *			buf:		ignored
   *			size:		zero
   *
   * OR
   *
   * Input:
   *			buf:		C string containing the pathname
   *					of the directory on a local file
   *					system containing permanent NFSv4
   *					recovery data
   *			size:		non-zero length of C string in @buf
   * Output:
   *	On success:	passed-in buffer filled with '
  '-terminated C string
   *			containing the current recovery pathname setting;
   *			return code is the size in bytes of the string
   *	On error:	return code is zero or a negative errno value
   */

  static ssize_t write_recoverydir(struct file *file, char *buf, size_t size)
  {
  	ssize_t rv;

  	struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id);

  
  	mutex_lock(&nfsd_mutex);

  	rv = __write_recoverydir(file, buf, size, nn);

  	mutex_unlock(&nfsd_mutex);
  	return rv;
  }

  /**
   * write_v4_end_grace - release grace period for nfsd's v4.x lock manager
   *
   * Input:
   *			buf:		ignored
   *			size:		zero
   * OR
   *
   * Input:
   * 			buf:		any value
   *			size:		non-zero length of C string in @buf
   * Output:
   *			passed-in buffer filled with "Y" or "N" with a newline
   *			and NULL-terminated C string. This indicates whether
   *			the grace period has ended in the current net
   *			namespace. Return code is the size in bytes of the
   *			string. Writing a string that starts with 'Y', 'y', or
   *			'1' to the file will end the grace period for nfsd's v4
   *			lock manager.
   */
  static ssize_t write_v4_end_grace(struct file *file, char *buf, size_t size)
  {

  	struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id);

  
  	if (size > 0) {
  		switch(buf[0]) {
  		case 'Y':
  		case 'y':
  		case '1':
  			nfsd4_end_grace(nn);
  			break;
  		default:
  			return -EINVAL;
  		}
  	}
  
  	return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%c
  ",
  			 nn->grace_ended ? 'Y' : 'N');
  }

  #endif

  /*----------------------------------------------------------------------------*/
  /*
   *	populating the filesystem.
   */
  
  static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
  {
  	static struct tree_descr nfsd_files[] = {

  		[NFSD_List] = {"exports", &exports_nfsd_operations, S_IRUGO},

  		[NFSD_Export_features] = {"export_features",
  					&export_features_operations, S_IRUGO},

  		[NFSD_FO_UnlockIP] = {"unlock_ip",
  					&transaction_ops, S_IWUSR|S_IRUSR},

  		[NFSD_FO_UnlockFS] = {"unlock_filesystem",
  					&transaction_ops, S_IWUSR|S_IRUSR},

  		[NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
  		[NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},

  		[NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR},

  		[NFSD_Pool_Stats] = {"pool_stats", &pool_stats_operations, S_IRUGO},

  		[NFSD_Reply_Cache_Stats] = {"reply_cache_stats", &reply_cache_stats_operations, S_IRUGO},

  		[NFSD_Versions] = {"versions", &transaction_ops, S_IWUSR|S_IRUSR},

  		[NFSD_Ports] = {"portlist", &transaction_ops, S_IWUSR|S_IRUGO},

  		[NFSD_MaxBlkSize] = {"max_block_size", &transaction_ops, S_IWUSR|S_IRUGO},

  		[NFSD_MaxConnections] = {"max_connections", &transaction_ops, S_IWUSR|S_IRUGO},

  #if defined(CONFIG_SUNRPC_GSS) || defined(CONFIG_SUNRPC_GSS_MODULE)

  		[NFSD_SupportedEnctypes] = {"supported_krb5_enctypes", &supported_enctypes_ops, S_IRUGO},

  #endif /* CONFIG_SUNRPC_GSS or CONFIG_SUNRPC_GSS_MODULE */

  #ifdef CONFIG_NFSD_V4
  		[NFSD_Leasetime] = {"nfsv4leasetime", &transaction_ops, S_IWUSR|S_IRUSR},

  		[NFSD_Gracetime] = {"nfsv4gracetime", &transaction_ops, S_IWUSR|S_IRUSR},

  		[NFSD_RecoveryDir] = {"nfsv4recoverydir", &transaction_ops, S_IWUSR|S_IRUSR},

  		[NFSD_V4EndGrace] = {"v4_end_grace", &transaction_ops, S_IWUSR|S_IRUGO},

  #endif
  		/* last one */ {""}
  	};

  	get_net(sb->s_fs_info);
  	return simple_fill_super(sb, 0x6e667364, nfsd_files);

  }

  static struct dentry *nfsd_mount(struct file_system_type *fs_type,
  	int flags, const char *dev_name, void *data)

  {

  	struct net *net = current->nsproxy->net_ns;
  	return mount_ns(fs_type, flags, data, net, net->user_ns, nfsd_fill_super);

  }
  
  static void nfsd_umount(struct super_block *sb)
  {
  	struct net *net = sb->s_fs_info;
  
  	kill_litter_super(sb);
  	put_net(net);

  }
  
  static struct file_system_type nfsd_fs_type = {
  	.owner		= THIS_MODULE,
  	.name		= "nfsd",

  	.mount		= nfsd_mount,

  	.kill_sb	= nfsd_umount,

  };

  MODULE_ALIAS_FS("nfsd");

  #ifdef CONFIG_PROC_FS
  static int create_proc_exports_entry(void)
  {
  	struct proc_dir_entry *entry;
  
  	entry = proc_mkdir("fs/nfs", NULL);
  	if (!entry)
  		return -ENOMEM;

  	entry = proc_create("exports", 0, entry,
  				 &exports_proc_operations);

  	if (!entry) {
  		remove_proc_entry("fs/nfs", NULL);

  		return -ENOMEM;

  	}

  	return 0;
  }
  #else /* CONFIG_PROC_FS */
  static int create_proc_exports_entry(void)
  {
  	return 0;
  }
  #endif

  int nfsd_net_id;

  
  static __net_init int nfsd_init_net(struct net *net)
  {
  	int retval;

  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

  
  	retval = nfsd_export_init(net);
  	if (retval)
  		goto out_export_error;

  	retval = nfsd_idmap_init(net);
  	if (retval)
  		goto out_idmap_error;

  	nn->nfsd4_lease = 90;	/* default lease time */

  	nn->nfsd4_grace = 90;

  	nn->clverifier_counter = prandom_u32();
  	nn->clientid_counter = prandom_u32();

  	return 0;

  out_idmap_error:
  	nfsd_export_shutdown(net);

  out_export_error:
  	return retval;
  }
  
  static __net_exit void nfsd_exit_net(struct net *net)
  {

  	nfsd_idmap_shutdown(net);

  	nfsd_export_shutdown(net);
  }

  static struct pernet_operations nfsd_net_ops = {

  	.init = nfsd_init_net,
  	.exit = nfsd_exit_net,

  	.id   = &nfsd_net_id,
  	.size = sizeof(struct nfsd_net),
  };

  static int __init init_nfsd(void)
  {
  	int retval;
  	printk(KERN_INFO "Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
  ");

  	retval = register_pernet_subsys(&nfsd_net_ops);
  	if (retval < 0)

  		return retval;
  	retval = register_cld_notifier();

  	if (retval)

  		goto out_unregister_pernet;

  	retval = nfsd4_init_slabs();
  	if (retval)
  		goto out_unregister_notifier;

  	retval = nfsd4_init_pnfs();

  	if (retval)
  		goto out_free_slabs;

  	retval = nfsd_fault_inject_init(); /* nfsd fault injection controls */
  	if (retval)
  		goto out_exit_pnfs;

  	nfsd_stat_init();	/* Statistics */

  	retval = nfsd_reply_cache_init();
  	if (retval)
  		goto out_free_stat;

  	nfsd_lockd_init();	/* lockd->nfsd callbacks */

  	retval = create_proc_exports_entry();
  	if (retval)

  		goto out_free_lockd;

  	retval = register_filesystem(&nfsd_fs_type);

  	if (retval)
  		goto out_free_all;
  	return 0;
  out_free_all:

  	remove_proc_entry("fs/nfs/exports", NULL);
  	remove_proc_entry("fs/nfs", NULL);

  out_free_lockd:

  	nfsd_lockd_shutdown();

  	nfsd_reply_cache_shutdown();

  out_free_stat:
  	nfsd_stat_shutdown();

  	nfsd_fault_inject_cleanup();

  out_exit_pnfs:
  	nfsd4_exit_pnfs();

  out_free_slabs:

  	nfsd4_free_slabs();

  out_unregister_notifier:

  	unregister_cld_notifier();

  out_unregister_pernet:
  	unregister_pernet_subsys(&nfsd_net_ops);

  	return retval;
  }
  
  static void __exit exit_nfsd(void)
  {

  	nfsd_reply_cache_shutdown();

  	remove_proc_entry("fs/nfs/exports", NULL);
  	remove_proc_entry("fs/nfs", NULL);
  	nfsd_stat_shutdown();
  	nfsd_lockd_shutdown();

  	nfsd4_free_slabs();

  	nfsd4_exit_pnfs();

  	nfsd_fault_inject_cleanup();

  	unregister_filesystem(&nfsd_fs_type);

  	unregister_cld_notifier();

  	unregister_pernet_subsys(&nfsd_net_ops);

  }
  
  MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
  MODULE_LICENSE("GPL");
  module_init(init_nfsd)
  module_exit(exit_nfsd)