/*
   *  linux/fs/nfs/proc.c
   *
   *  Copyright (C) 1992, 1993, 1994  Rick Sladkey
   *
   *  OS-independent nfs remote procedure call functions
   *
   *  Tuned by Alan Cox <A.Cox@swansea.ac.uk> for >3K buffers
   *  so at last we can have decent(ish) throughput off a 
   *  Sun server.
   *
   *  Coding optimized and cleaned up by Florian La Roche.
   *  Note: Error returns are optimized for NFS_OK, which isn't translated via
   *  nfs_stat_to_errno(), but happens to be already the right return code.
   *
   *  Also, the code currently doesn't check the size of the packet, when
   *  it decodes the packet.
   *
   *  Feel free to fix it and mail me the diffs if it worries you.
   *
   *  Completely rewritten to support the new RPC call interface;
   *  rewrote and moved the entire XDR stuff to xdr.c
   *  --Olaf Kirch June 1996
   *
   *  The code below initializes all auto variables explicitly, otherwise
   *  it will fail to work as a module (gcc generates a memset call for an
   *  incomplete struct).
   */
  
  #include <linux/types.h>
  #include <linux/param.h>

  #include <linux/time.h>
  #include <linux/mm.h>

  #include <linux/errno.h>
  #include <linux/string.h>
  #include <linux/in.h>
  #include <linux/pagemap.h>
  #include <linux/sunrpc/clnt.h>
  #include <linux/nfs.h>
  #include <linux/nfs2.h>
  #include <linux/nfs_fs.h>
  #include <linux/nfs_page.h>
  #include <linux/lockd/bind.h>

  #include <linux/freezer.h>

  #include "internal.h"

  
  #define NFSDBG_FACILITY		NFSDBG_PROC

  /*

   * wrapper to handle the -EKEYEXPIRED error message. This should generally
   * only happen if using krb5 auth and a user's TGT expires. NFSv2 doesn't
   * support the NFSERR_JUKEBOX error code, but we handle this situation in the
   * same way that we handle that error with NFSv3.
   */
  static int
  nfs_rpc_wrapper(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
  {
  	int res;
  	do {
  		res = rpc_call_sync(clnt, msg, flags);
  		if (res != -EKEYEXPIRED)
  			break;

  		freezable_schedule_timeout_killable(NFS_JUKEBOX_RETRY_TIME);

  		res = -ERESTARTSYS;
  	} while (!fatal_signal_pending(current));
  	return res;
  }
  
  #define rpc_call_sync(clnt, msg, flags)	nfs_rpc_wrapper(clnt, msg, flags)
  
  static int
  nfs_async_handle_expired_key(struct rpc_task *task)
  {
  	if (task->tk_status != -EKEYEXPIRED)
  		return 0;
  	task->tk_status = 0;
  	rpc_restart_call(task);
  	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
  	return 1;
  }
  
  /*

   * Bare-bones access to getattr: this is for nfs_read_super.
   */
  static int
  nfs_proc_get_root(struct nfs_server *server, struct nfs_fh *fhandle,
  		  struct nfs_fsinfo *info)
  {
  	struct nfs_fattr *fattr = info->fattr;
  	struct nfs2_fsstat fsinfo;

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_GETATTR],
  		.rpc_argp	= fhandle,
  		.rpc_resp	= fattr,
  	};

  	int status;

  	dprintk("%s: call getattr
  ", __func__);

  	nfs_fattr_init(fattr);

  	status = rpc_call_sync(server->client, &msg, 0);
  	/* Retry with default authentication if different */
  	if (status && server->nfs_client->cl_rpcclient != server->client)
  		status = rpc_call_sync(server->nfs_client->cl_rpcclient, &msg, 0);

  	dprintk("%s: reply getattr: %d
  ", __func__, status);

  	if (status)
  		return status;

  	dprintk("%s: call statfs
  ", __func__);

  	msg.rpc_proc = &nfs_procedures[NFSPROC_STATFS];
  	msg.rpc_resp = &fsinfo;

  	status = rpc_call_sync(server->client, &msg, 0);
  	/* Retry with default authentication if different */
  	if (status && server->nfs_client->cl_rpcclient != server->client)
  		status = rpc_call_sync(server->nfs_client->cl_rpcclient, &msg, 0);

  	dprintk("%s: reply statfs: %d
  ", __func__, status);

  	if (status)
  		return status;
  	info->rtmax  = NFS_MAXDATA;
  	info->rtpref = fsinfo.tsize;
  	info->rtmult = fsinfo.bsize;
  	info->wtmax  = NFS_MAXDATA;
  	info->wtpref = fsinfo.tsize;
  	info->wtmult = fsinfo.bsize;
  	info->dtpref = fsinfo.tsize;
  	info->maxfilesize = 0x7FFFFFFF;
  	info->lease_time = 0;
  	return 0;
  }
  
  /*
   * One function for each procedure in the NFS protocol.
   */
  static int
  nfs_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle,
  		struct nfs_fattr *fattr)
  {

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_GETATTR],
  		.rpc_argp	= fhandle,
  		.rpc_resp	= fattr,
  	};

  	int	status;
  
  	dprintk("NFS call  getattr
  ");

  	nfs_fattr_init(fattr);

  	status = rpc_call_sync(server->client, &msg, 0);

  	dprintk("NFS reply getattr: %d
  ", status);
  	return status;
  }
  
  static int
  nfs_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
  		 struct iattr *sattr)
  {
  	struct inode *inode = dentry->d_inode;
  	struct nfs_sattrargs	arg = { 
  		.fh	= NFS_FH(inode),
  		.sattr	= sattr
  	};

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_SETATTR],
  		.rpc_argp	= &arg,
  		.rpc_resp	= fattr,
  	};

  	int	status;

  	/* Mask out the non-modebit related stuff from attr->ia_mode */
  	sattr->ia_mode &= S_IALLUGO;

  	dprintk("NFS call  setattr
  ");

  	if (sattr->ia_valid & ATTR_FILE)
  		msg.rpc_cred = nfs_file_cred(sattr->ia_file);

  	nfs_fattr_init(fattr);

  	status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);

  	if (status == 0)
  		nfs_setattr_update_inode(inode, sattr);

  	dprintk("NFS reply setattr: %d
  ", status);
  	return status;
  }
  
  static int

  nfs_proc_lookup(struct rpc_clnt *clnt, struct inode *dir, struct qstr *name,

  		struct nfs_fh *fhandle, struct nfs_fattr *fattr)
  {
  	struct nfs_diropargs	arg = {
  		.fh		= NFS_FH(dir),
  		.name		= name->name,
  		.len		= name->len
  	};
  	struct nfs_diropok	res = {
  		.fh		= fhandle,
  		.fattr		= fattr
  	};

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_LOOKUP],
  		.rpc_argp	= &arg,
  		.rpc_resp	= &res,
  	};

  	int			status;
  
  	dprintk("NFS call  lookup %s
  ", name->name);

  	nfs_fattr_init(fattr);

  	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);

  	dprintk("NFS reply lookup: %d
  ", status);
  	return status;
  }
  
  static int nfs_proc_readlink(struct inode *inode, struct page *page,
  		unsigned int pgbase, unsigned int pglen)
  {
  	struct nfs_readlinkargs	args = {
  		.fh		= NFS_FH(inode),
  		.pgbase		= pgbase,
  		.pglen		= pglen,
  		.pages		= &page
  	};

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_READLINK],
  		.rpc_argp	= &args,
  	};

  	int			status;
  
  	dprintk("NFS call  readlink
  ");

  	status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);

  	dprintk("NFS reply readlink: %d
  ", status);
  	return status;
  }

  struct nfs_createdata {
  	struct nfs_createargs arg;
  	struct nfs_diropok res;
  	struct nfs_fh fhandle;
  	struct nfs_fattr fattr;
  };
  
  static struct nfs_createdata *nfs_alloc_createdata(struct inode *dir,
  		struct dentry *dentry, struct iattr *sattr)
  {
  	struct nfs_createdata *data;
  
  	data = kmalloc(sizeof(*data), GFP_KERNEL);
  
  	if (data != NULL) {
  		data->arg.fh = NFS_FH(dir);
  		data->arg.name = dentry->d_name.name;
  		data->arg.len = dentry->d_name.len;
  		data->arg.sattr = sattr;
  		nfs_fattr_init(&data->fattr);
  		data->fhandle.size = 0;
  		data->res.fh = &data->fhandle;
  		data->res.fattr = &data->fattr;
  	}
  	return data;
  };
  
  static void nfs_free_createdata(const struct nfs_createdata *data)
  {
  	kfree(data);
  }

  static int
  nfs_proc_create(struct inode *dir, struct dentry *dentry, struct iattr *sattr,

  		int flags, struct nfs_open_context *ctx)

  {

  	struct nfs_createdata *data;

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_CREATE],

  	};

  	int status = -ENOMEM;

  	dprintk("NFS call  create %s
  ", dentry->d_name.name);

  	data = nfs_alloc_createdata(dir, dentry, sattr);
  	if (data == NULL)
  		goto out;
  	msg.rpc_argp = &data->arg;
  	msg.rpc_resp = &data->res;

  	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);

  	nfs_mark_for_revalidate(dir);

  	if (status == 0)

  		status = nfs_instantiate(dentry, data->res.fh, data->res.fattr);
  	nfs_free_createdata(data);
  out:

  	dprintk("NFS reply create: %d
  ", status);
  	return status;
  }
  
  /*
   * In NFSv2, mknod is grafted onto the create call.
   */
  static int
  nfs_proc_mknod(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
  	       dev_t rdev)
  {

  	struct nfs_createdata *data;

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_CREATE],

  	};

  	umode_t mode;
  	int status = -ENOMEM;

  
  	dprintk("NFS call  mknod %s
  ", dentry->d_name.name);
  
  	mode = sattr->ia_mode;
  	if (S_ISFIFO(mode)) {
  		sattr->ia_mode = (mode & ~S_IFMT) | S_IFCHR;
  		sattr->ia_valid &= ~ATTR_SIZE;
  	} else if (S_ISCHR(mode) || S_ISBLK(mode)) {
  		sattr->ia_valid |= ATTR_SIZE;
  		sattr->ia_size = new_encode_dev(rdev);/* get out your barf bag */
  	}

  	data = nfs_alloc_createdata(dir, dentry, sattr);
  	if (data == NULL)
  		goto out;
  	msg.rpc_argp = &data->arg;
  	msg.rpc_resp = &data->res;

  	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);

  	nfs_mark_for_revalidate(dir);

  
  	if (status == -EINVAL && S_ISFIFO(mode)) {
  		sattr->ia_mode = mode;

  		nfs_fattr_init(data->res.fattr);

  		status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);

  	}
  	if (status == 0)

  		status = nfs_instantiate(dentry, data->res.fh, data->res.fattr);
  	nfs_free_createdata(data);
  out:

  	dprintk("NFS reply mknod: %d
  ", status);
  	return status;
  }
    
  static int
  nfs_proc_remove(struct inode *dir, struct qstr *name)
  {

  	struct nfs_removeargs arg = {
  		.fh = NFS_FH(dir),
  		.name.len = name->len,
  		.name.name = name->name,

  	};

  	struct rpc_message msg = { 
  		.rpc_proc = &nfs_procedures[NFSPROC_REMOVE],
  		.rpc_argp = &arg,

  	};
  	int			status;
  
  	dprintk("NFS call  remove %s
  ", name->name);
  	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);

  	nfs_mark_for_revalidate(dir);

  
  	dprintk("NFS reply remove: %d
  ", status);
  	return status;
  }

  static void
  nfs_proc_unlink_setup(struct rpc_message *msg, struct inode *dir)

  {

  	msg->rpc_proc = &nfs_procedures[NFSPROC_REMOVE];

  }

  static int nfs_proc_unlink_done(struct rpc_task *task, struct inode *dir)

  {

  	if (nfs_async_handle_expired_key(task))
  		return 0;

  	nfs_mark_for_revalidate(dir);
  	return 1;

  }

  static void
  nfs_proc_rename_setup(struct rpc_message *msg, struct inode *dir)
  {
  	msg->rpc_proc = &nfs_procedures[NFSPROC_RENAME];
  }
  
  static int
  nfs_proc_rename_done(struct rpc_task *task, struct inode *old_dir,
  		     struct inode *new_dir)
  {
  	if (nfs_async_handle_expired_key(task))
  		return 0;
  	nfs_mark_for_revalidate(old_dir);
  	nfs_mark_for_revalidate(new_dir);
  	return 1;
  }

  static int
  nfs_proc_rename(struct inode *old_dir, struct qstr *old_name,
  		struct inode *new_dir, struct qstr *new_name)
  {
  	struct nfs_renameargs	arg = {

  		.old_dir	= NFS_FH(old_dir),
  		.old_name	= old_name,
  		.new_dir	= NFS_FH(new_dir),
  		.new_name	= new_name,

  	};

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_RENAME],
  		.rpc_argp	= &arg,
  	};

  	int			status;
  
  	dprintk("NFS call  rename %s -> %s
  ", old_name->name, new_name->name);

  	status = rpc_call_sync(NFS_CLIENT(old_dir), &msg, 0);

  	nfs_mark_for_revalidate(old_dir);
  	nfs_mark_for_revalidate(new_dir);

  	dprintk("NFS reply rename: %d
  ", status);
  	return status;
  }
  
  static int
  nfs_proc_link(struct inode *inode, struct inode *dir, struct qstr *name)
  {
  	struct nfs_linkargs	arg = {
  		.fromfh		= NFS_FH(inode),
  		.tofh		= NFS_FH(dir),
  		.toname		= name->name,
  		.tolen		= name->len
  	};

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_LINK],
  		.rpc_argp	= &arg,
  	};

  	int			status;
  
  	dprintk("NFS call  link %s
  ", name->name);

  	status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);

  	nfs_mark_for_revalidate(inode);

  	nfs_mark_for_revalidate(dir);

  	dprintk("NFS reply link: %d
  ", status);
  	return status;
  }
  
  static int

  nfs_proc_symlink(struct inode *dir, struct dentry *dentry, struct page *page,
  		 unsigned int len, struct iattr *sattr)

  {

  	struct nfs_fh *fh;
  	struct nfs_fattr *fattr;

  	struct nfs_symlinkargs	arg = {
  		.fromfh		= NFS_FH(dir),

  		.fromname	= dentry->d_name.name,
  		.fromlen	= dentry->d_name.len,

  		.pages		= &page,
  		.pathlen	= len,

  		.sattr		= sattr
  	};

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_SYMLINK],
  		.rpc_argp	= &arg,
  	};

  	int status = -ENAMETOOLONG;
  
  	dprintk("NFS call  symlink %s
  ", dentry->d_name.name);

  	if (len > NFS2_MAXPATHLEN)

  		goto out;

  	fh = nfs_alloc_fhandle();
  	fattr = nfs_alloc_fattr();
  	status = -ENOMEM;
  	if (fh == NULL || fattr == NULL)

  		goto out_free;

  	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);

  	nfs_mark_for_revalidate(dir);

  
  	/*
  	 * V2 SYMLINK requests don't return any attributes.  Setting the
  	 * filehandle size to zero indicates to nfs_instantiate that it
  	 * should fill in the data with a LOOKUP call on the wire.
  	 */

  	if (status == 0)
  		status = nfs_instantiate(dentry, fh, fattr);

  out_free:

  	nfs_free_fattr(fattr);
  	nfs_free_fhandle(fh);
  out:

  	dprintk("NFS reply symlink: %d
  ", status);
  	return status;
  }
  
  static int
  nfs_proc_mkdir(struct inode *dir, struct dentry *dentry, struct iattr *sattr)
  {

  	struct nfs_createdata *data;

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_MKDIR],

  	};

  	int status = -ENOMEM;

  
  	dprintk("NFS call  mkdir %s
  ", dentry->d_name.name);

  	data = nfs_alloc_createdata(dir, dentry, sattr);
  	if (data == NULL)
  		goto out;
  	msg.rpc_argp = &data->arg;
  	msg.rpc_resp = &data->res;

  	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);

  	nfs_mark_for_revalidate(dir);

  	if (status == 0)

  		status = nfs_instantiate(dentry, data->res.fh, data->res.fattr);
  	nfs_free_createdata(data);
  out:

  	dprintk("NFS reply mkdir: %d
  ", status);
  	return status;
  }
  
  static int
  nfs_proc_rmdir(struct inode *dir, struct qstr *name)
  {
  	struct nfs_diropargs	arg = {
  		.fh		= NFS_FH(dir),
  		.name		= name->name,
  		.len		= name->len
  	};

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_RMDIR],
  		.rpc_argp	= &arg,
  	};

  	int			status;
  
  	dprintk("NFS call  rmdir %s
  ", name->name);

  	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);

  	nfs_mark_for_revalidate(dir);

  	dprintk("NFS reply rmdir: %d
  ", status);
  	return status;
  }
  
  /*
   * The READDIR implementation is somewhat hackish - we pass a temporary
   * buffer to the encode function, which installs it in the receive
   * the receive iovec. The decode function just parses the reply to make
   * sure it is syntactically correct; the entries itself are decoded
   * from nfs_readdir by calling the decode_entry function directly.
   */
  static int
  nfs_proc_readdir(struct dentry *dentry, struct rpc_cred *cred,

  		 u64 cookie, struct page **pages, unsigned int count, int plus)

  {
  	struct inode		*dir = dentry->d_inode;
  	struct nfs_readdirargs	arg = {
  		.fh		= NFS_FH(dir),
  		.cookie		= cookie,
  		.count		= count,

  		.pages		= pages,

  	};
  	struct rpc_message	msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_READDIR],
  		.rpc_argp	= &arg,

  		.rpc_cred	= cred,

  	};
  	int			status;

  	dprintk("NFS call  readdir %d
  ", (unsigned int)cookie);
  	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);

  	nfs_invalidate_atime(dir);

  	dprintk("NFS reply readdir: %d
  ", status);

  	return status;
  }
  
  static int
  nfs_proc_statfs(struct nfs_server *server, struct nfs_fh *fhandle,
  			struct nfs_fsstat *stat)
  {
  	struct nfs2_fsstat fsinfo;

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_STATFS],
  		.rpc_argp	= fhandle,
  		.rpc_resp	= &fsinfo,
  	};

  	int	status;
  
  	dprintk("NFS call  statfs
  ");

  	nfs_fattr_init(stat->fattr);

  	status = rpc_call_sync(server->client, &msg, 0);

  	dprintk("NFS reply statfs: %d
  ", status);
  	if (status)
  		goto out;
  	stat->tbytes = (u64)fsinfo.blocks * fsinfo.bsize;
  	stat->fbytes = (u64)fsinfo.bfree  * fsinfo.bsize;
  	stat->abytes = (u64)fsinfo.bavail * fsinfo.bsize;
  	stat->tfiles = 0;
  	stat->ffiles = 0;
  	stat->afiles = 0;
  out:
  	return status;
  }
  
  static int
  nfs_proc_fsinfo(struct nfs_server *server, struct nfs_fh *fhandle,
  			struct nfs_fsinfo *info)
  {
  	struct nfs2_fsstat fsinfo;

  	struct rpc_message msg = {
  		.rpc_proc	= &nfs_procedures[NFSPROC_STATFS],
  		.rpc_argp	= fhandle,
  		.rpc_resp	= &fsinfo,
  	};

  	int	status;
  
  	dprintk("NFS call  fsinfo
  ");

  	nfs_fattr_init(info->fattr);

  	status = rpc_call_sync(server->client, &msg, 0);

  	dprintk("NFS reply fsinfo: %d
  ", status);
  	if (status)
  		goto out;
  	info->rtmax  = NFS_MAXDATA;
  	info->rtpref = fsinfo.tsize;
  	info->rtmult = fsinfo.bsize;
  	info->wtmax  = NFS_MAXDATA;
  	info->wtpref = fsinfo.tsize;
  	info->wtmult = fsinfo.bsize;
  	info->dtpref = fsinfo.tsize;
  	info->maxfilesize = 0x7FFFFFFF;
  	info->lease_time = 0;
  out:
  	return status;
  }
  
  static int
  nfs_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
  		  struct nfs_pathconf *info)
  {
  	info->max_link = 0;
  	info->max_namelen = NFS2_MAXNAMLEN;
  	return 0;
  }

  static int nfs_read_done(struct rpc_task *task, struct nfs_read_data *data)

  {

  	if (nfs_async_handle_expired_key(task))
  		return -EAGAIN;

  	nfs_invalidate_atime(data->inode);

  	if (task->tk_status >= 0) {
  		nfs_refresh_inode(data->inode, data->res.fattr);
  		/* Emulate the eof flag, which isn't normally needed in NFSv2
  		 * as it is guaranteed to always return the file attributes
  		 */
  		if (data->args.offset + data->args.count >= data->res.fattr->size)
  			data->res.eof = 1;
  	}

  	return 0;

  }

  static void nfs_proc_read_setup(struct nfs_read_data *data, struct rpc_message *msg)

  {

  	msg->rpc_proc = &nfs_procedures[NFSPROC_READ];

  }

  static int nfs_write_done(struct rpc_task *task, struct nfs_write_data *data)

  {

  	if (nfs_async_handle_expired_key(task))
  		return -EAGAIN;

  	if (task->tk_status >= 0)

  		nfs_post_op_update_inode_force_wcc(data->inode, data->res.fattr);

  	return 0;

  }

  static void nfs_proc_write_setup(struct nfs_write_data *data, struct rpc_message *msg)

  {

  	/* Note: NFSv2 ignores @stable and always uses NFS_FILE_SYNC */
  	data->args.stable = NFS_FILE_SYNC;

  	msg->rpc_proc = &nfs_procedures[NFSPROC_WRITE];

  }
  
  static void

  nfs_proc_commit_setup(struct nfs_write_data *data, struct rpc_message *msg)

  {
  	BUG();
  }
  
  static int
  nfs_proc_lock(struct file *filp, int cmd, struct file_lock *fl)
  {

  	struct inode *inode = filp->f_path.dentry->d_inode;
  
  	return nlmclnt_proc(NFS_SERVER(inode)->nlm_host, cmd, fl);

  }

  /* Helper functions for NFS lock bounds checking */
  #define NFS_LOCK32_OFFSET_MAX ((__s32)0x7fffffffUL)
  static int nfs_lock_check_bounds(const struct file_lock *fl)
  {
  	__s32 start, end;
  
  	start = (__s32)fl->fl_start;
  	if ((loff_t)start != fl->fl_start)
  		goto out_einval;
  
  	if (fl->fl_end != OFFSET_MAX) {
  		end = (__s32)fl->fl_end;
  		if ((loff_t)end != fl->fl_end)
  			goto out_einval;
  	} else
  		end = NFS_LOCK32_OFFSET_MAX;
  
  	if (start < 0 || start > end)
  		goto out_einval;
  	return 0;
  out_einval:
  	return -EINVAL;
  }

  const struct nfs_rpc_ops nfs_v2_clientops = {

  	.version	= 2,		       /* protocol version */
  	.dentry_ops	= &nfs_dentry_operations,
  	.dir_inode_ops	= &nfs_dir_inode_operations,

  	.file_inode_ops	= &nfs_file_inode_operations,

  	.file_ops	= &nfs_file_operations,

  	.getroot	= nfs_proc_get_root,
  	.getattr	= nfs_proc_getattr,
  	.setattr	= nfs_proc_setattr,
  	.lookup		= nfs_proc_lookup,
  	.access		= NULL,		       /* access */
  	.readlink	= nfs_proc_readlink,

  	.create		= nfs_proc_create,
  	.remove		= nfs_proc_remove,
  	.unlink_setup	= nfs_proc_unlink_setup,
  	.unlink_done	= nfs_proc_unlink_done,
  	.rename		= nfs_proc_rename,

  	.rename_setup	= nfs_proc_rename_setup,
  	.rename_done	= nfs_proc_rename_done,

  	.link		= nfs_proc_link,
  	.symlink	= nfs_proc_symlink,
  	.mkdir		= nfs_proc_mkdir,
  	.rmdir		= nfs_proc_rmdir,
  	.readdir	= nfs_proc_readdir,
  	.mknod		= nfs_proc_mknod,
  	.statfs		= nfs_proc_statfs,
  	.fsinfo		= nfs_proc_fsinfo,
  	.pathconf	= nfs_proc_pathconf,

  	.decode_dirent	= nfs2_decode_dirent,

  	.read_setup	= nfs_proc_read_setup,

  	.read_done	= nfs_read_done,

  	.write_setup	= nfs_proc_write_setup,

  	.write_done	= nfs_write_done,

  	.commit_setup	= nfs_proc_commit_setup,

  	.lock		= nfs_proc_lock,

  	.lock_check_bounds = nfs_lock_check_bounds,

  	.close_context	= nfs_close_context,

  	.init_client	= nfs_init_client,

  };