nuttx/fs/nfs/nfs_vfsops.c

/****************************************************************************
 * fs/nfs/nfs_vfsops.c
 *
 *   Copyright (C) 2012 Gregory Nutt. All rights reserved.
 *   Copyright (C) 2012 Jose Pablo Rojas Vargas. All rights reserved.
 *   Author: Jose Pablo Rojas Vargas <jrojas@nx-engineering.com>
 *
 * Leveraged from OpenBSD:
 *
 *   Copyright (c) 1989, 1993, 1995
 *   The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Rick Macklem at The University of Guelph.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <sys/socket.h>
#include <sys/statfs.h>
#include <sys/stat.h>
#include <sys/types.h>

#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <queue.h>
#include <string.h>
#include <fcntl.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <time.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/dirent.h>
#include <nuttx/fs/fs.h>
#include <nuttx/fs/nfs.h>
#include <semaphore.h>

#include <net/if.h>
#include <netinet/in.h>

#include "nfs.h"
#include "rpc.h"
#include "nfs_proto.h"
#include "nfs_node.h"
#include "nfs_mount.h"
#include "xdr_subs.h"
#include "nfs_socket.h"

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

#define NFS_DIRHDSIZ         (sizeof (struct nfs_dirent) - (MAXNAMLEN + 1))
#define NFS_DIRENT_OVERHEAD  offsetof(struct nfs_dirent, dirent)

/****************************************************************************
 * Private Type Definitions
 ****************************************************************************/

struct nfs_dirent
{
  uint32_t cookie[2];
  struct dirent dirent;
};

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

static int     nfs_create(FAR struct nfsmount *nmp, struct nfsnode *np,
                   FAR const char *relpath, mode_t mode);
static int     nfs_open(FAR struct file *filep, const char *relpath,
                   int oflags, mode_t mode);
static ssize_t nfs_read(FAR struct file *filep, char *buffer, size_t buflen);
static ssize_t nfs_write(FAR struct file *filep, const char *buffer,
                   size_t buflen);
static int     nfs_opendir(struct inode *mountpt, const char *relpath,
                   struct fs_dirent_s *dir);
static int     nfs_readdir(struct inode *mountpt, struct fs_dirent_s *dir);
static int     nfs_bind(FAR struct inode *blkdriver, const void *data,
                   void **handle);
static int     nfs_unbind(void *handle, FAR struct inode **blkdriver);
static int     nfs_statfs(struct inode *mountpt, struct statfs *buf);
static int     nfs_remove(struct inode *mountpt, const char *relpath);
static int     nfs_mkdir(struct inode *mountpt, const char *relpath,
                   mode_t mode);
static int     nfs_rmdir(struct inode *mountpt, const char *relpath);
static int     nfs_rename(struct inode *mountpt, const char *oldrelpath,
                   const char *newrelpath);
static int     nfs_getfsinfo(struct nfsmount *nmp, const char *relpath,
                   struct stat *buf);
static int     nfs_fsinfo(struct inode *mountpt, const char *relpath,
                   struct stat *buf);

/****************************************************************************
 *  External Public Data  (this belong in a header file)
 ****************************************************************************/

extern uint32_t nfs_true;
extern uint32_t nfs_false;
extern uint32_t nfs_xdrneg1;
extern struct nfsstats nfsstats;
extern int nfs_ticks;

/****************************************************************************
 * Public Data
 ****************************************************************************/
/* nfs vfs operations. */

const struct mountpt_operations nfs_operations =
{
  nfs_open,                     /* open */
  NULL,                         /* close */
  nfs_read,                     /* read */
  nfs_write,                    /* write */
  NULL,                         /* seek */
  NULL,                         /* ioctl */
  NULL,                         /* sync */

  nfs_opendir,                  /* opendir */
  NULL,                         /* closedir */
  nfs_readdir,                  /* readdir */
  NULL,                         /* rewinddir */

  nfs_bind,                     /* bind */
  nfs_unbind,                   /* unbind */
  nfs_statfs,                   /* statfs */

  nfs_remove,                   /* unlink */
  nfs_mkdir,                    /* mkdir */
  nfs_rmdir,                    /* rmdir */
  nfs_rename,                   /* rename */
  nfs_fsinfo                    /* stat */
};

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

 /****************************************************************************
 * Name: nfs_create
 *
 * Description:
 *   Create a file.  This is part of the file open logic that is executed if
 *   the user asks to create a file.
 *
 * Returned Value:
 *   0 on success; a positive errno value on failure.
 *
 ****************************************************************************/

static int nfs_create(FAR struct nfsmount *nmp, struct nfsnode *np,
                      FAR const char *relpath, mode_t mode)
{
//struct nfs_fattr vap;
  struct nfsv3_sattr sp;
  struct CREATE3args create;
  struct rpc_reply_create resok;
  int error = 0;

  do
    {
      nfsstats.rpccnt[NFSPROC_CREATE]++;
      memset(&sp, 0, sizeof(struct nfsv3_sattr));
    //memset(&vap, 0, sizeof(struct nfs_fattr));
    //vap = nmp->nm_head->n_fattr;
      sp.sa_modetrue  = true;
      sp.sa_mode      = txdr_unsigned(mode);
      sp.sa_uidfalse  = nfs_xdrneg1;
      sp.sa_gidfalse  = nfs_xdrneg1;
      sp.sa_sizefalse = 0;
      sp.sa_atimetype = txdr_unsigned(NFSV3SATTRTIME_DONTCHANGE);
      sp.sa_mtimetype = txdr_unsigned(NFSV3SATTRTIME_DONTCHANGE);
    //txdr_nfsv3time2(&vap.fa3_atime, &sp.sa_atime);
    //txdr_nfsv3time2(&vap.fa3_mtime, &sp.sa_mtime);

      memset(&create, 0, sizeof(struct CREATE3args));
      memset(&resok, 0, sizeof(struct rpc_reply_create));
      memcpy(&create.how, &sp, sizeof(struct nfsv3_sattr));
#warning "BUG HERE: np has not yet been initialized"
      create.where.dir.length = txdr_unsigned(np->n_fhsize);
      memcpy(&create.where.dir.handle, &np->n_fhp, sizeof(nfsfh_t));
      create.where.length = txdr_unsigned(64);
      strncpy(create.where.name, relpath, 64);

      error = nfs_request(nmp, NFSPROC_CREATE, (FAR const void *)&create,
                          (void *)&resok, sizeof(struct rpc_reply_create));
    }
  while (error == EOPNOTSUPP);

  if (error == 0)
    {
      //np->nfsv3_type = fxdr_unsigned(uint32_t, resok.attributes.fa_type);

      np->n_open        = true;
      memcpy(&np->n_fhp, &resok.create.fshandle.handle, sizeof(nfsfh_t));
      np->n_size        = fxdr_hyper(&resok.create.attributes.fa3_size);
      memcpy(&resok.create.attributes, &np->n_fattr, sizeof(struct nfs_fattr));
      fxdr_nfsv3time(&resok.create.attributes.fa3_mtime, &np->n_mtime)
      np->n_ctime       = fxdr_hyper(&resok.create.attributes.fa3_ctime);
    }

  return error;
}

 /****************************************************************************
 * Name: nfs_open
 *
 * Description:
 *   If oflags == O_CREAT it creates a file, if not it check to see if the
 *   type is ok and that deletion is not in progress.
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.
 *
 ****************************************************************************/

static int nfs_open(FAR struct file *filep, FAR const char *relpath,
                    int oflags, mode_t mode)
{
  struct stat buf;
  struct inode *in;
//struct nfs_fattr vap;
  struct nfsmount *nmp;
  struct nfsnode *np;
  bool readonly;
  int error = 0;

  /* Sanity checks */

  DEBUGASSERT(filep->f_inode != NULL);

  /* Get the mountpoint inode reference from the file structure and the
   * mountpoint private data from the inode structure
   */

  in  = filep->f_inode;
  nmp = (struct nfsmount*)in->i_private;

  DEBUGASSERT(nmp != NULL);

  /* Pre-allocate the file private data to describe the opened file. */

  np = (struct nfsnode *)kzalloc(sizeof(struct nfsnode));
  if (!np)
    {
      fdbg("ERROR: Failed to allocate private data\n");
      return -ENOMEM;
    }

  /* Check if the mount is still healthy */

  nfs_semtake(nmp);
  error = nfs_checkmount(nmp);
  if (error != 0)
    {
      goto errout_with_semaphore;
    }

  /* First check if the file already exists */

  error = nfs_getfsinfo(nmp, relpath, &buf);
  if (error == 0)
    {
      /* Check if the file is a directory */

      if (S_ISDIR(buf.st_mode))
        {
          /* Exit with EISDIR if we attempt to open an directory */

          fdbg("ERROR: Path is a directory\n");
          error = EISDIR;
          goto errout_with_semaphore;
        }

      /* Check if the caller has sufficient privileges to open the file */

      readonly = ((buf.st_mode & (S_IWOTH|S_IWGRP|S_IXUSR)) == 0);
      if (((oflags & O_WRONLY) != 0) && readonly)
        {
          fdbg("ERROR: File is read-only\n");
          error = EACCES;
          goto errout_with_semaphore;
        }

      /* It would be an error if we are asked to create it exclusively */

      if ((oflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
        {
          /* Already exists -- can't create it exclusively */

          fdbg("ERROR: File exists\n");
          error = EEXIST;
          goto errout_with_semaphore;
        }

      /* If O_TRUNC is specified and the file is opened for writing,
       * then truncate the file.  This operation requires that the file is
       * writable, but we have already checked that. O_TRUNC without write
       * access is ignored.
       */

      if ((oflags & (O_TRUNC|O_WRONLY)) == (O_TRUNC|O_WRONLY))
        {
          /* Truncate the file to zero length */

          fvdbg("Truncating file\n");
#warning "Missing logic"
        }

      /* Initialize the file private data from the FSINFO return data */
      /* NOTE:  This will require some re-structuring */
#if 0
      np->n_open        = true;
      memcpy(&np->n_fhp, &resok.fsinfo.fshandle.handle, sizeof(nfsfh_t));
      np->n_size        = fxdr_hyper(&resok.fsinfo.attributes.fa3_size);
      memcpy(&resok.fsinfo.attributes, &np->n_fattr, sizeof(struct nfs_fattr));
      fxdr_nfsv3time(&resok.fsinfo.attributes.fa3_mtime, &np->n_mtime)
      np->n_ctime       = fxdr_hyper(&resok.fsinfo.attributes.fa3_ctime);
#else
#warning "Missing logic"
      fdbg("ERROR: Logic to open an existing file is not fully implemented");
      errno = ENOSYS; /* Just fail for now */
      goto errout_with_semaphore;
#endif
      /* Fall through to finish the file open operation */
    }

  /* An error occurred while getting the file status */

  else
    {
      /* Check if the stat failed because the file does not exist. */
#warning "Missing logic"

      /* If the file does not exist then check if we were asked to create
       * the file.  If the O_CREAT bit is set in the oflags then we should
       * create the file if it does not exist.
       */

      if ((oflags & O_CREAT) == 0)
        {
          /* Return ENOENT if the file does not exist and we were not asked
           * to create it.
           */

          fdbg("ERROR: File does not exist\n");
          error = ENOENT; 
          goto errout_with_semaphore;
        }
 
      /* Create the file */

      error = nfs_create(nmp, np, relpath, mode);
      if (error != 0)
        {
          fdbg("ERROR: nfs_create failed: %d\n", error);
          goto errout_with_semaphore;
        }

      /* Fall through to finish the file open operation */
    }

  /* Initialize the file private data (only need to initialize
   * non-zero elements)
   */

  /* Attach the private data to the struct file instance */

  filep->f_priv = np;

  /* Then insert the new instance into the mountpoint structure.
   * It needs to be there (1) to handle error conditions that effect
   * all files, and (2) to inform the umount logic that we are busy
   * (but a simple reference count could have done that).
   */

  np->n_next   = nmp->nm_head;
  np->n_flag  |= NMODIFIED;
  nmp->nm_head = np->n_next;

  /* For open/close consistency. */

  NFS_INVALIDATE_ATTRCACHE(np);
  nfs_semgive(nmp);
  return OK;

errout_with_semaphore:
  kfree(np);
  nfs_semgive(nmp);
  return -error;
}

#undef COMP
#ifdef COMP
/****************************************************************************
 * Name: nfs_close
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.
 *
 ****************************************************************************/

static int nfs_close(FAR struct file *filep) done
{
  struct nfsmount *nmp;
  struct nfsnode *np;
  int error = 0;

  fvdbg("Closing\n");

  /* Sanity checks */

  DEBUGASSERT(filep->f_priv != NULL && filep->f_inode != NULL);

  /* Recover our private data from the struct file instance */

  np = filep->f_priv;
  nmp = filep->f_inode->i_private;

  DEBUGASSERT(nmp != NULL);

  if (np->nfsv3_type == NFREG)
    {
      error = nfs_sync(filep);
      kfree(np);
      filep->f_priv = NULL;
    }

  return -error;
}
#endif

/****************************************************************************
 * Name: nfs_read
 *
 * Returned Value:
 *   The (non-negative) number of bytes read on success; a negated errno
 *   value on failure.
 *
 ****************************************************************************/

static ssize_t nfs_read(FAR struct file *filep, char *buffer, size_t buflen)
{
  struct nfsmount *nmp;
  struct nfsnode *np;
  uint32_t readsize;
  int bytesleft;
  uint64_t offset;
  struct READ3args read;
  struct rpc_reply_read resok;
  uint8_t *userbuffer = (uint8_t*)buffer;
  int error = 0;
  int len;

  fvdbg("Read %d bytes from offset %d\n", buflen, filep->f_pos);

  /* Sanity checks */

  DEBUGASSERT(filep->f_priv != NULL && filep->f_inode != NULL);

  /* Recover our private data from the struct file instance */

  np = (struct nfsnode*) filep->f_priv;
  nmp = (struct nfsmount*) filep->f_inode->i_private;
  offset = 0;

  DEBUGASSERT(nmp != NULL);

  /* Make sure that the mount is still healthy */

  nfs_semtake(nmp);
  error = nfs_checkmount(nmp);
  if (error != 0)
    {
      fdbg("nfs_checkmount failed: %d\n", error);
      goto errout_with_semaphore;
    }

  if (np->nfsv3_type != NFREG)
    {
      fdbg("read eacces typ=%d\n", np->nfsv3_type);
      error = EACCES;
      goto errout_with_semaphore;
    }

  if ((nmp->nm_flag & (NFSMNT_NFSV3 | NFSMNT_GOTFSINFO)) == NFSMNT_NFSV3)
    {
      (void)nfs_getfsinfo(nmp, NULL, NULL);
    }

  /* Get the number of bytes left in the file */

  bytesleft = np->n_size - filep->f_pos;
  readsize = 0;

  /* Truncate read count so that it does not exceed the number
   * of bytes left in the file.
   */

  if (buflen > bytesleft)
    {
      buflen = bytesleft;
    }

  len = nmp->nm_rsize;
  if (len < buflen)
    {
      error = EFBIG;
      goto errout_with_semaphore;
    }

  nfsstats.rpccnt[NFSPROC_READ]++;

again:
  memset(&read, 0, sizeof(struct READ3args));
  memset(&resok, 0, sizeof(struct rpc_reply_read));
  read.file = txdr_unsigned(np->nfsv3_type);
  read.count = txdr_unsigned(buflen);
  read.offset = txdr_unsigned(offset);

  error = nfs_request(nmp, NFSPROC_READ, (FAR const void *)&read,
                      (void *)&resok, sizeof(struct rpc_reply_read));
  if (error)
    {
      goto errout_with_semaphore;
    }

  if (resok.read.eof == true)
    {
      readsize = fxdr_unsigned(uint32_t, resok.read.count);
      np->n_fattr = resok.read.file_attributes;//
      memcpy(userbuffer, resok.read.data, readsize);
    }
  else
    {
      goto again;
    }

  nfs_semgive(nmp);
  return readsize;

errout_with_semaphore:
  nfs_semgive(nmp);
  return -error;
}

/****************************************************************************
 * Name: nfs_write
 *
 * Returned Value:
 *   The (non-negative) number of bytes written on success; a negated errno
 *   value on failure.
 *
 ****************************************************************************/

static ssize_t
nfs_write(FAR struct file *filep, const char *buffer, size_t buflen)
{
  struct inode *inode;
  struct nfsmount *nmp;
  struct nfsnode *np;
  unsigned int  writesize;
  struct WRITE3args write;
  struct rpc_reply_write resok;
  uint8_t  *userbuffer = (uint8_t*)buffer;
  int error = 0;
  uint64_t  offset;
  int len;
  int commit = 0;
  int committed = NFSV3WRITE_FILESYNC;

  /* Sanity checks */

  DEBUGASSERT(filep->f_priv != NULL && filep->f_inode != NULL);

  /* Recover our private data from the struct file instance */

  np     = (struct nfsnode *)filep->f_priv;
  inode  = filep->f_inode;
  nmp    = (struct nfsmount *)inode->i_private;
  offset = 0;

  DEBUGASSERT(nmp != NULL);

  /* Make sure that the mount is still healthy */

  nfs_semtake(nmp);
  error = nfs_checkmount(nmp);
  if (error != 0)
    {
      goto errout_with_semaphore;
    }

  /* Check if the file size would exceed the range of off_t */

  if (np->n_size + buflen < np->n_size)
    {
      error = EFBIG;
      goto errout_with_semaphore;
    }

  len = nmp->nm_wsize;
  if (len < buflen)
    {
      error = EFBIG;
      goto errout_with_semaphore;
    }

  writesize = 0;

  nfsstats.rpccnt[NFSPROC_WRITE]++;
  memset(&write, 0, sizeof(struct WRITE3args));
  memset(&resok, 0, sizeof(struct rpc_reply_write));
  write.file   = txdr_unsigned(np->nfsv3_type);
  write.offset = txdr_unsigned(offset);
  write.count  = txdr_unsigned(buflen);
  write.stable = txdr_unsigned(committed);
  memcpy((void *)write.data, userbuffer, buflen);

  error = nfs_request(nmp, NFSPROC_WRITE, (FAR const void *)&write,
                      (FAR void *)&resok, sizeof(struct rpc_reply_write));
  if (error)
    {
      goto errout_with_semaphore;
    }

  writesize = resok.write.count;
  if (writesize == 0)
    {
       error = EIO;
       goto errout_with_semaphore;
    }

  commit = resok.write.committed;
  memcpy(&np->n_fattr, &resok.write.file_wcc.after, sizeof(struct nfs_fattr));

  /* Return the lowest committment level obtained by any of the RPCs. */

  if (committed == NFSV3WRITE_FILESYNC)
    {
      committed = commit;
    }
  else if (committed == NFSV3WRITE_DATASYNC &&
           commit == NFSV3WRITE_UNSTABLE)
    {
      committed = commit;
    }

  if ((nmp->nm_flag & NFSMNT_HASWRITEVERF) == 0)
    {
      memcpy((void*) nmp->nm_verf, (void*) resok.write.verf, NFSX_V3WRITEVERF);
      nmp->nm_flag |= NFSMNT_HASWRITEVERF;
    }
  else if (strncmp((char*) resok.write.verf, (char*) nmp->nm_verf, NFSX_V3WRITEVERF))
    {
      memcpy((void*) nmp->nm_verf, (void*) resok.write.verf, NFSX_V3WRITEVERF);
    }

  fxdr_nfsv3time(&np->n_fattr.fa3_mtime, &np->n_mtime)

  nfs_semgive(nmp);
  return writesize;

errout_with_semaphore:
  nfs_semgive(nmp);
  return -error;
}

/****************************************************************************
 * Name: nfs_opendir
 *
 * Description:
 *   Open a directory for read access
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.
 *
 ****************************************************************************/

static int nfs_opendir(struct inode *mountpt, const char *relpath,
                         struct fs_dirent_s *dir)
{
  struct nfsmount *nmp;
  struct nfsnode *np;
//struct nfs_dirinfo_s dirinfo;
  int ret;

  fvdbg("relpath: \"%s\"\n", relpath ? relpath : "NULL");

  /* Sanity checks */

  DEBUGASSERT(mountpt != NULL && mountpt->i_private != NULL);

  /* Recover our private data from the inode instance */

  nmp = mountpt->i_private;
  np = nmp->nm_head;

  /* Make sure that the mount is still healthy */

  nfs_semtake(nmp);
  ret = nfs_checkmount(nmp);
  if (ret != OK)
    {
      fdbg("nfs_checkmount failed: %d\n", ret);
      goto errout_with_semaphore;
    }

  /* The entry is a directory */

  if (np->nfsv3_type != NFDIR)
    {
      fdbg("open eacces type=%d\n", np->nfsv3_type);
      ret = EACCES;
      goto errout_with_semaphore;
    }

  /* The requested directory must be the volume-relative "root" directory */

  if (relpath && relpath[0] != '\0')
    {
      ret = ENOENT;
      goto errout_with_semaphore;
    }

  if (np->n_flag & NMODIFIED)
    {
      if (np->nfsv3_type == NFDIR)
        {
           np->n_direofoffset = 0;
           dir->u.nfs.nd_direoffset = 0;
           dir->u.nfs.cookie[0] = 0;
           dir->u.nfs.cookie[1] = 0;
        }
    }

  ret = OK;

errout_with_semaphore:
  nfs_semgive(nmp);
  return -ret;
}

/****************************************************************************
 * Name: nfs_readdirrpc
 *
 * Description:
 *   The function below stuff the cookies in after the name.
 *
 * Returned Value:
 *   0 on success; a positive errno value on failure.
 *
 ****************************************************************************/

int nfs_readdirrpc(struct nfsmount *nmp, struct nfsnode *np,
                   struct fs_dirent_s *dir)
{
/* This buffer needs to go into struct fs_dirent_s nuttx/dirent.h */
  uint32_t buffer[64];
  struct READDIR3args rddir;
  struct rpc_reply_readdir *resok;
  uint32_t tmp;
  uint32_t *ptr; /* This goes in fs_dirent_s */
  uint8_t *name;
  unsigned int length;
  bool more;
  bool eod;
  int error = 0;

/* Check in 'dir' if we are have directories entries?  
 * 1) have data, and
 * 2) Index of the last returned entry has nextentry != 0
 *
 * If we have returned entries then read more entries if:
 * 3) EOF = 0
 */
 
  more = false;  /* Set 'more' to true if we have buffered entries to be processed */
  eod  = false;  /* Set 'eod' if we are at the end of the directory */

  /* Loop while we need more data (!more) and we are not at the end of
   * the directory (!eod)
   */

  while (!more && !eod)
    {
      /* Request a block directory enries */

      nfsstats.rpccnt[NFSPROC_READDIR]++;
      memset(&rddir, 0, sizeof(struct READDIR3args));
      rddir.dir.length = txdr_unsigned(np->n_fhsize);
      memcpy(&rddir.dir.handle, &np->n_fhp, sizeof(nfsfh_t));
      rddir.count = txdr_unsigned(nmp->nm_readdirsize);

      if (nfsstats.rpccnt[NFSPROC_READDIR] == 1)
        {
          rddir.cookie.nfsuquad[0] = 0;
          rddir.cookie.nfsuquad[1] = 0;
          memset(&rddir.cookieverf, 0, NFSX_V3COOKIEVERF);
        }
      else
        {
          rddir.cookie.nfsuquad[0] = dir->u.nfs.cookie[0];
          rddir.cookie.nfsuquad[1] = dir->u.nfs.cookie[1];
          memcpy(&rddir.cookieverf, &np->n_cookieverf, NFSX_V3COOKIEVERF);
        }

      error = nfs_request(nmp, NFSPROC_READDIR, (FAR const void *)&rddir,
                          (FAR void *)buffer, sizeof(buffer));
      if (error)
        {
          goto nfsmout;
        }

      /* A new group of entries was successfully read.  Process the
       * information contained in the response header.  This information
       * includes:
       *
       * 1) Attributes follow indication - 4 bytes
       * 2) Directory attributes         - sizeof(struct nfs_fattr)
       * 3) Cookie verifier              - NFSX_V3COOKIEVERF bytes
       * 4) Values follows indication    - 4 bytes
       */

      resok = (struct rpc_reply_readdir *)buffer;

      /* Start with the first entry */

      ptr = (uint32_t*)&resok->readdir;

       /* Check if attributes follow, if 0 so Skip over the attributes */

      if (resok->readdir.attributes_follow == 1)
        {
          /* Get attibutes */

           memcpy(&np->n_fattr, &resok->readdir.dir_attributes,
                  sizeof(struct nfs_fattr));
        }
#warning "Won't the structure format be wrong if there are no attributes -- this will need to be parsed too"

      /* Save the verification cookie */

      memcpy(&np->n_cookieverf, &resok->readdir.cookieverf, NFSX_V3WRITEVERF);

      /* Get a point to the entries (if any) */

      ptr  = (uint32_t*)&resok->readdir.reply;

      /* Check if values follow.  If no values follow, then the EOF indication
       * will appear next.
       */

      if (resok->readdir.value_follows == 0)
        {
          /* No values follow, then the reply should consist only of a 4-byte
           * end-of-directory indication.
           */

          more = false;       /* No entries follow */
          eod  = (*ptr != 0); /* We are (probably) at the end of the directory */
        }
      else
        {
          more = true;   /* Assume that entries follow */
          eod  = false;  /* Assume that we are not at the end of the directory */
        }
    }

  /* If we are not at the end of the directory listing, then a set of entries
   * will follow the header.  Each entry is of the form:
   *
   *    File ID (8 bytes)
   *    Name length (4 bytes)
   *    Name string (varaiable size but in multiples of 4 bytes)
   *    Cookie (8 bytes)
   *    next entry (4 bytes)
   *
   * If 'more' is true, then we have more directory entries to process.
   */

  if (more)
    {
      /* There is an entry. Get the file ID and point to the length */
      /* Missing logic to get the file ID */

      ptr += 2;

      /* Get the length and point to the name */

      tmp    = *ptr++;
      length = fxdr_unsigned(uint32_t, tmp);
      name   = (uint8_t*)ptr;

      /* Increment the pointer past the name (allowing for padding). ptr
       * now points to the cookie.
       */

      ptr += (length + 3) >> 2;

      /* Save the cookie and increment the pointer to the next entry */

      dir->u.nfs.cookie[0] = *ptr++;
      dir->u.nfs.cookie[1] = *ptr++;

      ptr++; /* Just skip over the nextentry for now */

      /* Return the directory entry to the caller.  On subsequent calls to
       * readdir(), we will return the next entry.  And so on until all of
       * the entries have been returned.  Then read the next next block
       * of entries until EOF is reported.
       */
#warning "Not implemented"

      /* Return the name of the node to the caller */

      if (length > NAME_MAX)
        {
          length = NAME_MAX;
        }
      memcpy(dir->fd_dir.d_name, name, length);
      dir->fd_dir.d_name[length] = '\0';
      fvdbg("name: \"%s\"\n", dir->fd_dir.d_name);

      /* Get the file attributes associated with this name and return
       * the file type.
       */

#if 0 /* There is no point in enabling until nfs_getfsinfo handles the relative path */
      if ((nmp->nm_flag & (NFSMNT_NFSV3 | NFSMNT_GOTFSINFO)) == NFSMNT_NFSV3)
        {
          struct stat buf
          char *path;

          /* Construct the full path to the file */

          asprintf(&path, "%s/%s", relpath, dir->fd_dir.d_name);
          if (path)
            {
              /* Then stat the file */

              int ret = nfs_getfsinfo(nmp, path, &buf);
              if (ret == OK)
                {
                  if (S_ISREG(buf.st_mode))
                    {
                      dir->fd_dir.d_type = DTYPE_FILE;
                    }
                  else if (S_ISDIR(buf.st_mode))
                    {
                      dir->fd_dir.d_type = DTYPE_FILE;
                    }
                  else if (S_ISCHR(buf.st_mode) || S_ISFIFO(buf.st_mode))
                    {
                      dir->fd_dir.d_type = DTYPE_FILE;
                    }
                  else if (S_ISBLK(buf.st_mode))
                    {
                      dir->fd_dir.d_type = DTYPE_FILE;
                    }
                  else
                    {
#warning "Other types should be ignored ... go to the next entry"
                    }
                }

              /* Free the allocated string */

              kfree(path);
            }
        }
#else
#warning "Missing logic"
      dir->fd_dir.d_type = DTYPE_FILE;
#endif
      error = 0;
    }

  /* We are at the end of the directory.  If 'eod' is true then we all of the
   * directory entries have been processed and we are at the end of the
   * directory.
   */

  if (eod)
    {
      /* We signal the end of the directory by returning the
       * special error -ENOENT
       */

      fvdbg("End of directory\n");
      error = ENOENT;
    }

nfsmout:
  return error;
}

/****************************************************************************
 * Name: nfs_readdir
 *
 * Description: Read from directory
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.
 *
 ****************************************************************************/

static int nfs_readdir(struct inode *mountpt, struct fs_dirent_s *dir)
{
  int error = 0;
  struct nfsmount *nmp;
  struct nfsnode *np;
//struct nfs_dirent *ndp;

  fvdbg("Entry\n");

  /* Sanity checks */

  DEBUGASSERT(mountpt != NULL && mountpt->i_private != NULL);

  /* Recover our private data from the inode instance */

  nmp          = mountpt->i_private;
  np           = nmp->nm_head;
  dir->fd_root = mountpt;

  /* Make sure that the mount is still healthy */

  nfs_semtake(nmp);
  error = nfs_checkmount(nmp);
  if (error != 0)
    {
      fdbg("ERROR: nfs_checkmount failed: %d\n", error);
      goto errout_with_semaphore;
    }

  dir->fd_dir.d_name[0] = '\0';

  if (np->nfsv3_type != NFDIR)
    {
      error = EPERM;
      goto errout_with_semaphore;
    }

  dir->u.nfs.nd_direoffset = np->n_direofoffset;
  dir->fd_dir.d_type = np->nfsv3_type;

  /* First, check for hit on the EOF offset */

  if (dir->u.nfs.nd_direoffset != 0)
    {
      nfsstats.direofcache_hits++;
    //np->n_open = true;
      goto success_with_semaphore;
    }

  if ((nmp->nm_flag & (NFSMNT_NFSV3 | NFSMNT_GOTFSINFO)) == NFSMNT_NFSV3)
    {
      (void)nfs_getfsinfo(nmp, NULL, NULL);
    }

  /* Read and return one directory entry.  */

  error = nfs_readdirrpc(nmp, np, dir);
  if (error != 0)
    {
      goto errout_with_semaphore;
    }

success_with_semaphore:
  error = 0;

errout_with_semaphore:
  nfs_semgive(nmp);
  return -error;
}

/****************************************************************************
 * Name: nfs_decode_args
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

void nfs_decode_args(struct nfsmount *nmp, struct nfs_args *argp)
{
  int adjsock = 0;
  int maxio;

#ifdef CONFIG_NFS_TCPIP
  /* Re-bind if rsrvd port requested and wasn't on one */

  adjsock = !(nmp->nm_flag & NFSMNT_RESVPORT)
    && (argp->flags & NFSMNT_RESVPORT);
#endif

  /* Also re-bind if we're switching to/from a connected UDP socket */

  adjsock |= ((nmp->nm_flag & NFSMNT_NOCONN) != (argp->flags & NFSMNT_NOCONN));

  /* Update flags atomically.  Don't change the lock bits. */

  nmp->nm_flag =
    (argp->flags & ~NFSMNT_INTERNAL) | (nmp->nm_flag & NFSMNT_INTERNAL);

  if ((argp->flags & NFSMNT_TIMEO) && argp->timeo > 0)
    {
      nmp->nm_timeo = (argp->timeo * NFS_HZ + 5) / 10;
      if (nmp->nm_timeo < NFS_MINTIMEO)
        {
          nmp->nm_timeo = NFS_MINTIMEO;
        }
      else if (nmp->nm_timeo > NFS_MAXTIMEO)
        {
          nmp->nm_timeo = NFS_MAXTIMEO;
        }
    }

  if ((argp->flags & NFSMNT_RETRANS) && argp->retrans > 1)
    {
      nmp->nm_retry = (argp->retrans < NFS_MAXREXMIT)? argp->retrans : NFS_MAXREXMIT;
    }

  if (!(nmp->nm_flag & NFSMNT_SOFT))
    {
      nmp->nm_retry = NFS_MAXREXMIT + 1;  /* past clip limit */
    }

  if (argp->flags & NFSMNT_NFSV3)
    {
      if (argp->sotype == SOCK_DGRAM)
        {
          maxio = NFS_MAXDGRAMDATA;
        }
      else
        {
          maxio = NFS_MAXDATA;
        }
    }
  else
    {
      maxio = NFS_V2MAXDATA;
    }

  if ((argp->flags & NFSMNT_WSIZE) && argp->wsize > 0)
    {
      int osize = nmp->nm_wsize;
      nmp->nm_wsize = argp->wsize;

      /* Round down to multiple of blocksize */

      nmp->nm_wsize &= ~(NFS_FABLKSIZE - 1);
      if (nmp->nm_wsize <= 0)
        {
          nmp->nm_wsize = NFS_FABLKSIZE;
        }

      adjsock |= (nmp->nm_wsize != osize);
    }

  if (nmp->nm_wsize > maxio)
    {
      nmp->nm_wsize = maxio;
    }

  if (nmp->nm_wsize > MAXBSIZE)
    {
      nmp->nm_wsize = MAXBSIZE;
    }

  if ((argp->flags & NFSMNT_RSIZE) && argp->rsize > 0)
    {
      int osize = nmp->nm_rsize;
      nmp->nm_rsize = argp->rsize;

      /* Round down to multiple of blocksize */

      nmp->nm_rsize &= ~(NFS_FABLKSIZE - 1);
      if (nmp->nm_rsize <= 0)
        {
          nmp->nm_rsize = NFS_FABLKSIZE;
        }

      adjsock |= (nmp->nm_rsize != osize);
    }

  if (nmp->nm_rsize > maxio)
    {
      nmp->nm_rsize = maxio;
    }

  if (nmp->nm_rsize > MAXBSIZE)
    {
      nmp->nm_rsize = MAXBSIZE;
    }

  if ((argp->flags & NFSMNT_READDIRSIZE) && argp->readdirsize > 0)
    {
      nmp->nm_readdirsize = argp->readdirsize;

      /* Round down to multiple of blocksize */

      nmp->nm_readdirsize &= ~(NFS_DIRBLKSIZ - 1);
      if (nmp->nm_readdirsize < NFS_DIRBLKSIZ)
        {
          nmp->nm_readdirsize = NFS_DIRBLKSIZ;
        }
    }
  else if (argp->flags & NFSMNT_RSIZE)
    {
      nmp->nm_readdirsize = nmp->nm_rsize;
    }

  if (nmp->nm_readdirsize > maxio)
    {
      nmp->nm_readdirsize = maxio;
    }

/*
  if ((argp->flags & NFSMNT_MAXGRPS) && argp->maxgrouplist >= 0 &&
      argp->maxgrouplist <= NFS_MAXGRPS)
    {
      nmp->nm_numgrps = argp->maxgrouplist;
    }

  if ((argp->flags & NFSMNT_READAHEAD) && argp->readahead >= 0 &&
      argp->readahead <= NFS_MAXRAHEAD)
    {
      nmp->nm_readahead = argp->readahead;
    }
*/

  if (argp->flags & NFSMNT_ACREGMIN && argp->acregmin >= 0)
    {
      if (argp->acregmin > 0xffff)
        {
          nmp->nm_acregmin = 0xffff;
        }
      else
        {
          nmp->nm_acregmin = argp->acregmin;
        }
    }

  if (argp->flags & NFSMNT_ACREGMAX && argp->acregmax >= 0)
    {
      if (argp->acregmax > 0xffff)
        {
          nmp->nm_acregmax = 0xffff;
        }
      else
        {
          nmp->nm_acregmax = argp->acregmax;
        }
    }

  if (nmp->nm_acregmin > nmp->nm_acregmax)
    {
      nmp->nm_acregmin = nmp->nm_acregmax;
    }

  if (argp->flags & NFSMNT_ACDIRMIN && argp->acdirmin >= 0)
    {
      if (argp->acdirmin > 0xffff)
        {
          nmp->nm_acdirmin = 0xffff;
        }
      else
        {
          nmp->nm_acdirmin = argp->acdirmin;
        }
    }

  if (argp->flags & NFSMNT_ACDIRMAX && argp->acdirmax >= 0)
    {
      if (argp->acdirmax > 0xffff)
        {
          nmp->nm_acdirmax = 0xffff;
        }
      else
        {
          nmp->nm_acdirmax = argp->acdirmax;
        }
    }

  if (nmp->nm_acdirmin > nmp->nm_acdirmax)
    {
      nmp->nm_acdirmin = nmp->nm_acdirmax;
    }

  if (nmp->nm_so && adjsock)
    {
      nfs_disconnect(nmp);
      if (nmp->nm_sotype == SOCK_DGRAM)
        {
          while (nfs_connect(nmp))
            {
              fvdbg("nfs_args: retrying connect\n");
            }
        }
    }
}

/****************************************************************************
 * Name: mountnfs
 *
 * Description:
 *   Common code for nfs_mount.
 *
 * Returned Value:
 *   0 on success; a positive errno value on failure.
 *
 ****************************************************************************/

int mountnfs(struct nfs_args *argp, void **handle)
{
  FAR struct nfsmount *nmp;
  struct nfsnode *np = NULL;
  struct FS3args getattr;
  struct rpc_reply_getattr resok;
  int error = 0;

  /* Create an instance of the mountpt state structure */

  nmp = (FAR struct nfsmount *)kzalloc(sizeof(struct nfsmount));
  if (!nmp)
    {
      fdbg("ERROR: Failed to allocate mountpoint structure\n");
      return ENOMEM;
    }

  /* Initialize the allocated mountpt state structure. */

  /* Initialize the semaphore that controls access.  The initial count
   * is zero, but nfs_semgive() is called at the completion of initialization,
   * incrementing the count to one.
   */

  sem_init(&nmp->nm_sem, 0, 0);     /* Initialize the semaphore that controls access */

  /* Initialize NFS */

  nfs_init();

  /* Set initial values of other fields */

  nmp->nm_flag        = argp->flags;
  nmp->nm_timeo       = NFS_TIMEO;
  nmp->nm_retry       = NFS_RETRANS;
  nmp->nm_wsize       = NFS_WSIZE;
  nmp->nm_rsize       = NFS_RSIZE;
  nmp->nm_readdirsize = NFS_READDIRSIZE;
  nmp->nm_numgrps     = NFS_MAXGRPS;
  nmp->nm_readahead   = NFS_DEFRAHEAD;
  nmp->nm_fhsize      = NFSX_V3FHMAX;
  nmp->nm_acregmin    = NFS_MINATTRTIMO;
  nmp->nm_acregmax    = NFS_MAXATTRTIMO;
  nmp->nm_acdirmin    = NFS_MINATTRTIMO;
  nmp->nm_acdirmax    = NFS_MAXATTRTIMO;

  strncpy(nmp->nm_path, argp->path, 90);
  memcpy(&nmp->nm_nam, &argp->addr, argp->addrlen);

  nfs_decode_args(nmp, argp);

  /* Set up the sockets and per-host congestion */

  nmp->nm_sotype  = argp->sotype;
  nmp->nm_soproto = argp->proto;

  /* For Connection based sockets (TCP,...) defer the connect until
   * the first request, in case the server is not responding.
   */

  if (nmp->nm_sotype == SOCK_DGRAM)
    {
      /* Connection-less... connect now */

      error = nfs_connect(nmp);
      if (error != 0)
        {
          fdbg("ERROR: nfs_connect failed: %d\n", error);
          goto bad;
        }
    }

  /* Create an instance of the file private data to describe the opened
   * file.
   */

  np = (struct nfsnode *)kzalloc(sizeof(struct nfsnode));
  if (!np)
    {
      fdbg("ERROR: Failed to allocate private data\n");
      error = ENOMEM;
      goto bad;
     }

  np->nfsv3_type         = NFDIR;
  np->n_open             = true;
  np->n_flag            |= NMODIFIED;
  nmp->nm_head           = np;
  nmp->nm_mounted        = true;
  memcpy(&nmp->nm_fh, &nmp->nm_rpcclnt->rc_fh, sizeof(nfsfh_t));
  nmp->nm_fhsize         = NFSX_V2FH;
  memcpy(&nmp->nm_head->n_fhp, &nmp->nm_fh, sizeof(nfsfh_t));
  nmp->nm_head->n_fhsize = nmp->nm_fhsize;
  nmp->nm_so             = nmp->nm_rpcclnt->rc_so;

  /* Get the file attributes */

  memset(&getattr, 0, sizeof(struct FS3args));
  memset(&resok, 0, sizeof(struct rpc_reply_getattr));
  getattr.fsroot.length = txdr_unsigned(nmp->nm_fhsize);
  memcpy(&getattr.fsroot.handle, &nmp->nm_fh, sizeof(nfsfh_t));

  error = nfs_request(nmp, NFSPROC_GETATTR, (FAR const void *)&getattr,
                      (FAR void*)&resok, sizeof(struct rpc_reply_getattr));
  if (error)
    {
      fdbg("ERROR: nfs_request failed: %d\n", error);
      goto bad;
    }

  /* Save the file attributes */

  memcpy(&np->n_fattr, &resok.attr, sizeof(struct nfs_fattr));
  memcpy(&nmp->nm_fattr, &resok.attr, sizeof(struct nfs_fattr));

  /* Mounted! */

  *handle = (void*)nmp;
  nfs_semgive(nmp);

  fvdbg("Successfully mounted\n");
  return 0;

bad:
  /* Free all memory that was successfully allocated */

  if (np)
    {
      kfree(np);
    }

  if (nmp)
    {
      /* Disconnect from the server */

      nfs_disconnect(nmp);

      /* Free connection-related resources */

      sem_destroy(&nmp->nm_sem);
      if (nmp->nm_so)
        {
          kfree(nmp->nm_so);
        }
      if (nmp->nm_rpcclnt)
        {
          kfree(nmp->nm_rpcclnt);
        }
      kfree(nmp);
    }
  return error;
}

/****************************************************************************
 * Name: nfs_bind
 *
 * Description: This implements a portion of the mount operation. This
 *  function allocates and initializes the mountpoint private data and
 *  binds the blockdriver inode to the filesystem private data.  The final
 *  binding of the private data (containing the blockdriver) to the
 *  mountpoint is performed by mount().
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.
 *
 ****************************************************************************/

static int nfs_bind(struct inode *blkdriver, const void *data, void **handle)
{
  struct nfs_args args;
  int error;

  memcpy(&args, data, sizeof(struct nfs_args));
  if (args.version == NFS_ARGSVERSION)
    {
      args.flags &= ~(NFSMNT_INTERNAL | NFSMNT_NOAC);
    }
   else
    {
      return -EINVAL;
    }

  if ((args.flags & (NFSMNT_NFSV3 | NFSMNT_RDIRPLUS)) == NFSMNT_RDIRPLUS)
    {
      return -EINVAL;
    }

  error = mountnfs(&args, handle);
  return -error;
}

/****************************************************************************
 * Name: nfs_unbind
 *
 * Description: This implements the filesystem portion of the umount
 *   operation.
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.
 *
 ****************************************************************************/

int nfs_unbind(void *handle, struct inode **blkdriver)
{
  struct nfsmount *nmp = (struct nfsmount *)handle;
  int error;

  fvdbg("Entry\n");

  if (!nmp)
    {
      return -EINVAL;
    }

  nfs_semtake(nmp);

  /* Umount */

  error = rpcclnt_umount(nmp->nm_rpcclnt);
  if (error)
    {
      fdbg("ERROR: rpcclnt_umount failed: %d\n", error);
    }

  /* Disconnect */

  nfs_disconnect(nmp);

  /* And free resources */

  sem_destroy(&nmp->nm_sem);
  kfree(nmp->nm_head);
  kfree(nmp->nm_so);
  kfree(nmp->nm_rpcclnt);
  kfree(nmp);

  return -error;
}

/****************************************************************************
 * Name: nfs_statfs
 *
 * Description:
 *   Return filesystem statistics
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.
 *
 ****************************************************************************/

static int nfs_statfs(struct inode *mountpt, struct statfs *sbp)
{
  struct rpc_reply_fsstat sfp;
  struct nfsmount *nmp;
  int error = 0;
  uint64_t tquad;
  struct FS3args fsstat;

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

  /* Get the mountpoint private data from the inode structure */

  nmp = (struct nfsmount*)mountpt->i_private;

  /* Check if the mount is still healthy */

  nfs_semtake(nmp);
  error = nfs_checkmount(nmp);
  if (error < 0)
    {
      fdbg("nfs_checkmount failed: %d\n", error);
      goto errout_with_semaphore;
    }

  /* Fill in the statfs info */

  memset(sbp, 0, sizeof(struct statfs));
  sbp->f_type = NFS_SUPER_MAGIC;

  if ((nmp->nm_flag & NFSMNT_GOTFSINFO) == 0)
    {
      (void)nfs_getfsinfo(nmp, NULL, NULL);
    }

  nfsstats.rpccnt[NFSPROC_FSSTAT]++;
  memset(&fsstat, 0, sizeof(struct FS3args));
  memset(&sfp, 0, sizeof(struct rpc_reply_fsstat));
  fsstat.fsroot.length = txdr_unsigned(nmp->nm_fhsize);
  fsstat.fsroot.handle = nmp->nm_fh;

  error = nfs_request(nmp, NFSPROC_FSSTAT, (FAR const void *)&fsstat,
                      (FAR void *) &sfp, sizeof(struct rpc_reply_fsstat));
  if (error)
    {
      goto errout_with_semaphore;
    }

  nmp->nm_head->n_fattr = sfp.fsstat.obj_attributes;
  sbp->f_bsize          = NFS_FABLKSIZE;
  tquad                 = fxdr_hyper(&sfp.fsstat.sf_tbytes);
  sbp->f_blocks         = tquad / (uint64_t) NFS_FABLKSIZE;
  tquad                 = fxdr_hyper(&sfp.fsstat.sf_fbytes);
  sbp->f_bfree          = tquad / (uint64_t) NFS_FABLKSIZE;
  tquad                 = fxdr_hyper(&sfp.fsstat.sf_abytes);
  sbp->f_bavail         = tquad / (uint64_t) NFS_FABLKSIZE;
  tquad                 = fxdr_hyper(&sfp.fsstat.sf_tfiles);
  sbp->f_files          = tquad;
  tquad                 = fxdr_hyper(&sfp.fsstat.sf_ffiles);
  sbp->f_ffree          = tquad;
  sbp->f_namelen        = NAME_MAX;

errout_with_semaphore:
  nfs_semgive(nmp);
  return -error;
}

/****************************************************************************
 * Name: nfs_remove
 *
 * Description:
 *   Remove a file
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.
 *
 ****************************************************************************/

static int nfs_remove(struct inode *mountpt, const char *relpath)
{
  struct nfsmount *nmp;
  struct nfsnode *np;
  struct REMOVE3args remove;
  struct rpc_reply_remove resok;
  int error = 0;

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

  /* Get the mountpoint private data from the inode structure */

  nmp = (struct nfsmount*)mountpt->i_private;
  np = nmp->nm_head;

  /* Check if the mount is still healthy */

  nfs_semtake(nmp);
  error = nfs_checkmount(nmp);
  if (error == 0)
    {
      /* If the file is open, the correct behavior is to remove the file
       * name, but to keep the file cluster chain in place until the last
       * open reference to the file is closed.
       */

      /* Remove the file */

      if (np->nfsv3_type != NFREG)
        {
          error = EPERM;
          goto errout_with_semaphore;
        }

      /* Do the rpc */

      nfsstats.rpccnt[NFSPROC_REMOVE]++;
      memset(&remove, 0, sizeof(struct REMOVE3args));
      memset(&resok, 0, sizeof(struct rpc_reply_remove));
      remove.object.dir.length = txdr_unsigned(np->n_fhsize);
      memcpy(&remove.object.dir.handle, &np->n_fhp, sizeof(nfsfh_t));
      remove.object.length = txdr_unsigned(64);
      strncpy(remove.object.name, relpath, 64);

      error = nfs_request(nmp, NFSPROC_REMOVE, (FAR const void *)&remove,
                          (FAR void*)&resok, sizeof(struct rpc_reply_remove));

      /* Kludge City: If the first reply to the remove rpc is lost..
       *   the reply to the retransmitted request will be ENOENT
       *   since the file was in fact removed
       *   Therefore, we cheat and return success.
       */

      if (error == ENOENT)
        {
          error = 0;
        }

      if (error)
        {
          goto errout_with_semaphore;
        }

      memcpy(&np->n_fattr, &resok.remove.dir_wcc.after, sizeof(struct nfs_fattr));
      np->n_flag |= NMODIFIED;
    }

   NFS_INVALIDATE_ATTRCACHE(np);

errout_with_semaphore:
   nfs_semgive(nmp);
   return -error;
}

/****************************************************************************
 * Name: nfs_mkdir
 *
 * Description:
 *   Create a directory
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.
 *
 ****************************************************************************/

static int nfs_mkdir(struct inode *mountpt, const char *relpath, mode_t mode)
{
  struct nfsv3_sattr sp;
  struct nfsmount *nmp;
  struct nfsnode *np;
  struct MKDIR3args mkir;
  struct rpc_reply_mkdir resok;
  int error = 0;

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

  /* Get the mountpoint private data from the inode structure */

  nmp = (struct nfsmount*) mountpt->i_private;
  np = nmp->nm_head;

  /* Check if the mount is still healthy */

  nfs_semtake(nmp);
  error = nfs_checkmount(nmp);
  if (error != 0)
    {
      goto errout_with_semaphore;
    }

  nfsstats.rpccnt[NFSPROC_MKDIR]++;
  memset(&mkir, 0, sizeof(struct MKDIR3args));
  memset(&resok, 0, sizeof(struct rpc_reply_mkdir));
  mkir.where.dir.length = txdr_unsigned(np->n_fhsize);
  memcpy(&mkir.where.dir.handle, &np->n_fhp, sizeof(nfsfh_t));
  mkir.where.length = txdr_unsigned(64);
  strncpy(mkir.where.name, relpath, 64);

  sp.sa_modetrue  = nfs_true;
  sp.sa_mode      = txdr_unsigned(mode);
  sp.sa_uidfalse  = 0;
  sp.sa_gidfalse  = 0;
  sp.sa_sizefalse = 0;
  sp.sa_atimetype = txdr_unsigned(NFSV3SATTRTIME_DONTCHANGE);
  sp.sa_mtimetype = txdr_unsigned(NFSV3SATTRTIME_DONTCHANGE);

//memset(&sp.sa_atime, 0, sizeof(nfstime3));
//memset(&sp.sa_mtime, 0, sizeof(nfstime3));

  memcpy(&mkir.attributes, &sp, sizeof(struct nfsv3_sattr));

  error = nfs_request(nmp, NFSPROC_MKDIR, (FAR const void *)&mkir,
                      (FAR void *)&resok, sizeof(struct rpc_reply_mkdir));
  if (error)
    {
      goto errout_with_semaphore;
    }

  np->n_open        = true;
  np->nfsv3_type    = fxdr_unsigned(uint32_t, resok.mkdir.obj_attributes.fa_type);
  memcpy(&np->n_fhp, &resok.mkdir.fshandle.handle, sizeof(nfsfh_t));
  np->n_size        = fxdr_hyper(&resok.mkdir.obj_attributes.fa3_size);
  memcpy(&np->n_fattr, &resok.mkdir.obj_attributes, sizeof(struct nfs_fattr));
  fxdr_nfsv3time(&resok.mkdir.obj_attributes.fa3_mtime, &np->n_mtime)
  np->n_ctime       = fxdr_hyper(&resok.mkdir.obj_attributes.fa3_ctime);
  np->n_flag       |= NMODIFIED;

  NFS_INVALIDATE_ATTRCACHE(np);

errout_with_semaphore:
  nfs_semgive(nmp);
  return -error;
}

/****************************************************************************
 * Name: nfs_rmdir
 *
 * Description:
 *   Remove a directory
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.
 *
 ****************************************************************************/

static int nfs_rmdir(struct inode *mountpt, const char *relpath)
{
  struct nfsmount *nmp;
  struct nfsnode *np;
  struct RMDIR3args rmdir;
  struct rpc_reply_rmdir resok;
  int error = 0;

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

  /* Get the mountpoint private data from the inode structure */

  nmp = (struct nfsmount *)mountpt->i_private;
  np  = nmp->nm_head;

  /* Check if the mount is still healthy */

  nfs_semtake(nmp);
  error = nfs_checkmount(nmp);
  if (error == 0)
    {
      /* Remove the directory */

      if (np->nfsv3_type != NFDIR)
        {
          error = EPERM;
          goto errout_with_semaphore;
        }

      /* Do the rpc */

      nfsstats.rpccnt[NFSPROC_RMDIR]++;
      memset(&rmdir, 0, sizeof(struct RMDIR3args));
      memset(&resok, 0, sizeof(struct rpc_reply_rmdir));
      rmdir.object.dir.length = txdr_unsigned(np->n_fhsize);
      memcpy(&rmdir.object.dir.handle, &np->n_fhp, sizeof(nfsfh_t));
      rmdir.object.length = txdr_unsigned(64);
      strncpy(rmdir.object.name, relpath, 64);

      error = nfs_request(nmp, NFSPROC_RMDIR, (FAR const void *)&rmdir,
                          (FAR void *)&resok, sizeof(struct rpc_reply_rmdir));
      if (error == ENOENT)
        {
          error = 0;
        }

      if (error)
        {
          goto errout_with_semaphore;
        }

      memcpy(&np->n_fattr, &resok.rmdir.dir_wcc.after, sizeof(struct nfs_fattr));
      np->n_flag |= NMODIFIED;
    }

  NFS_INVALIDATE_ATTRCACHE(np);

errout_with_semaphore:
  nfs_semgive(nmp);
  return -error;
}

/****************************************************************************
 * Name: nfs_rename
 *
 * Description:
 *   Rename a file or directory
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.
 *
 ****************************************************************************/

static int nfs_rename(struct inode *mountpt, const char *oldrelpath,
                      const char *newrelpath)
{
  struct nfsmount *nmp;
  struct nfsnode *np;
  struct RENAME3args rename;
  struct rpc_reply_rename resok;
  int error = 0;

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

  /* Get the mountpoint private data from the inode structure */

  nmp = (struct nfsmount *)mountpt->i_private;
  np  = nmp->nm_head;

  /* Check if the mount is still healthy */

  nfs_semtake(nmp);
  error = nfs_checkmount(nmp);
  if (error != 0)
    {
      goto errout_with_semaphore;
    }

  if (np->nfsv3_type != NFREG && np->nfsv3_type != NFDIR)
    {
      fdbg("open eacces typ=%d\n", np->nfsv3_type);
      error = EACCES;
      goto errout_with_semaphore;
    }

  nfsstats.rpccnt[NFSPROC_RENAME]++;
  memset(&rename, 0, sizeof(struct RENAME3args));
  memset(&resok, 0, sizeof(struct rpc_reply_rename));
  rename.from.dir.length = txdr_unsigned(np->n_fhsize);
  memcpy(&rename.from.dir.handle, &np->n_fhp, sizeof(nfsfh_t));
  rename.from.length = txdr_unsigned(64);
  strncpy(rename.from.name, oldrelpath, 64);
  rename.to.dir.length = txdr_unsigned(np->n_fhsize);
  memcpy(&rename.to.dir.handle, &np->n_fhp, sizeof(nfsfh_t));
  rename.to.length = txdr_unsigned(64);
  strncpy(rename.to.name, newrelpath, 64);

  error = nfs_request(nmp, NFSPROC_RENAME, (FAR const void *)&rename,
                      (FAR void *)&resok, sizeof(struct rpc_reply_rename));

  /* ENOENT => 0 assuming that it is a reply to a retry. */

  if (error == ENOENT)
    {
      error = 0;
    }

  if (error)
    {
      goto errout_with_semaphore;
    }

  memcpy(&np->n_fattr, &resok.rename.todir_wcc.after, sizeof(struct nfs_fattr));
  np->n_flag |= NMODIFIED;
  NFS_INVALIDATE_ATTRCACHE(np);

errout_with_semaphore:
  nfs_semgive(nmp);
  return -error;
}

/****************************************************************************
 * Name: nfs_getfsinfo
 *
 * Description:
 *   Return information about root directory.  This is an internal version
 *   used only within this file.
 *
 * Returned Value:
 *   0 on success; positive errno value on failure
 *
 * Assumptions:
 *   The caller has exclusive access to the NFS mount structure
 *
 ****************************************************************************/

static int nfs_getfsinfo(struct nfsmount *nmp, const char *relpath,
                         struct stat *buf)
{
  struct rpc_reply_fsinfo fsp;
  struct FS3args fsinfo;
  uint32_t pref;
  uint32_t max;
  int error = 0;

#warning "relpath is not used!  Additional logic will be required!"

  memset(&fsinfo, 0, sizeof(struct FS3args));
  memset(&fsp,    0, sizeof(struct rpc_reply_fsinfo));

  nfsstats.rpccnt[NFSPROC_FSINFO]++;
  fsinfo.fsroot.length = txdr_unsigned(nmp->nm_fhsize);
  fsinfo.fsroot.handle = nmp->nm_fh;

  /* Request FSINFO from the server */

  error = nfs_request(nmp, NFSPROC_FSINFO, (FAR const void *)&fsinfo,
                      (FAR void *)&fsp, sizeof(struct rpc_reply_fsinfo));
  if (error)
    {
      return error;
    }

//nmp->nm_fattr = fsp.obj_attributes;
  pref = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_wtpref);
  if (pref < nmp->nm_wsize)
    {
      nmp->nm_wsize = (pref + NFS_FABLKSIZE - 1) & ~(NFS_FABLKSIZE - 1);
    }

  max = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_wtmax);
  if (max < nmp->nm_wsize)
    {
      nmp->nm_wsize = max & ~(NFS_FABLKSIZE - 1);
      if (nmp->nm_wsize == 0)
        {
          nmp->nm_wsize = max;
        }
    }

  pref = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_rtpref);
  if (pref < nmp->nm_rsize)
    {
      nmp->nm_rsize = (pref + NFS_FABLKSIZE - 1) & ~(NFS_FABLKSIZE - 1);
    }

  max = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_rtmax);
  if (max < nmp->nm_rsize)
    {
      nmp->nm_rsize = max & ~(NFS_FABLKSIZE - 1);
      if (nmp->nm_rsize == 0)
        {
          nmp->nm_rsize = max;
        }
    }

  pref = fxdr_unsigned(uint32_t, fsp.fsinfo.fs_dtpref);
  if (pref < nmp->nm_readdirsize)
    {
      nmp->nm_readdirsize = (pref + NFS_DIRBLKSIZ - 1) & ~(NFS_DIRBLKSIZ - 1);
    }

  if (max < nmp->nm_readdirsize)
    {
      nmp->nm_readdirsize = max & ~(NFS_DIRBLKSIZ - 1);
      if (nmp->nm_readdirsize == 0)
        {
          nmp->nm_readdirsize = max;
        }
    }

  /* Verify that the caller has provided a non-NULL location to return the
   * FSINFO data.
   */

  if (buf)
    {
      /* Construct the file mode.  This is a 32-bit, encoded value containing
       * both the access mode and the file type.
       */

      uint32_t tmp = fxdr_unsigned(uint32_t, nmp->nm_fattr.fa_mode);
      
      /* Here we exploit the fact that most mode bits are the same in NuttX
       * as in the NFSv3 spec.
       */

      uint32_t mode = tmp & (NFSMMODE_IXOTH|NFSMMODE_IWOTH|NFSMMODE_IROTH|
                             NFSMMODE_IXGRP|NFSMMODE_IWGRP|NFSMMODE_IRGRP|
                             NFSMMODE_IXUSR|NFSMMODE_IWUSR|NFSMMODE_IRUSR);

      /* Handle the cases that are not the same */

      if ((mode & NFSMMODE_ISGID) != 0)
        {
          mode |= S_ISGID;
        }

      if ((mode & NFSMMODE_ISUID) != 0)
        {
          mode |= S_ISUID;
        }

      /* Now OR in the file type */

      tmp = fxdr_unsigned(uint32_t, nmp->nm_fattr.fa_type);
      switch (tmp)
        {
        default:
        case NFNON:   /* Unknown type */
          break;

        case NFREG:   /* Regular file */
          mode |= S_IFREG;
          break;

        case NFDIR:   /* Directory */
          mode |= S_IFDIR;
          break;

        case NFBLK:   /* Block special device file */
          mode |= S_IFBLK;
          break;

        case NFCHR:   /* Character special device file */
          mode |= S_IFCHR;
          break;

        case NFLNK:   /* Symbolic link */
          mode |= S_IFLNK;
          break;

        case NFSOCK:  /* Socket */
          mode |= S_IFSOCK;
          break;

        case NFFIFO:  /* Named pipe */
          mode |= S_IFMT;
          break;
        };

      buf->st_mode    = mode;
      buf->st_size    = fxdr_hyper(&nmp->nm_fattr.fa3_size);
      buf->st_blksize = 0;
      buf->st_blocks  = 0;
      buf->st_mtime   = fxdr_hyper(&nmp->nm_fattr.fa3_mtime);
      buf->st_atime   = fxdr_hyper(&nmp->nm_fattr.fa3_atime);
      buf->st_ctime   = fxdr_hyper(&nmp->nm_fattr.fa3_ctime);
    }

  nmp->nm_flag |= NFSMNT_GOTFSINFO;

  return 0;
}

/****************************************************************************
 * Name: nfs_fsinfo
 *
 * Description:
 *   Return information about root directory
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.
 *
 ****************************************************************************/

static int nfs_fsinfo(struct inode *mountpt, const char *relpath,
                      struct stat *buf)
{
  struct nfsmount *nmp;
  int error;

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

  /* Get the mountpoint private data from the inode structure */

  nmp = (struct nfsmount*)mountpt->i_private;

  /* Check if the mount is still healthy */

  nfs_semtake(nmp);
  error = nfs_checkmount(nmp);
  if (error == 0)
    {
      /* Get the requested FSINFO */

      error = nfs_getfsinfo(nmp, relpath, buf);
    }

  nfs_semgive(nmp);
  return -error;
}

#ifdef COMP
/****************************************************************************
 * Name: nfs_sync
 *
 * Description: Flush out the buffer cache
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.
 *
 ****************************************************************************/

int nfs_sync(struct file *filep)
{
  struct inode *inode;
  struct nfsmount *nmp;
  struct nfsnode *np;
  int error = 0;

  /* Sanity checks */

  DEBUGASSERT(filep->f_priv != NULL && filep->f_inode != NULL);

  /* Recover our private data from the struct file instance */

  np    = filep->f_priv;
  inode = filep->f_inode;
  nmp   = inode->i_private;

  DEBUGASSERT(nmp != NULL);

  /* Make sure that the mount is still healthy */

  nfs_semtake(nmp);
  error = nfs_checkmount(nmp);
  if (error != 0)
    {
      goto errout_with_semaphore;
    }

  /* Force stale buffer cache information to be flushed. */

  /* Check if the has been modified in any way */

  if ((np->n_flag & NMODIFIED) != 0)
    {
      //error = VOP_FSYNC(vp, cred, waitfor, p);
    }

errout_with_semaphore:
  nfs_semgive(nmp);
  return -error;
}
#endif