path: root/nuttx/fs/smartfs/smartfs_smart.c

/****************************************************************************
 * fs/smartfs/smartfs_smart.c
 *
 *   Copyright (C) 2013 Ken Pettit. All rights reserved.
 *   Author: Ken Pettit <pettitkd@gmail.com>
 *
 * 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 NuttX 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 COPYRIGHT HOLDERS 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
 * COPYRIGHT OWNER 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/types.h>
#include <sys/stat.h>
#include <sys/statfs.h>

#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <semaphore.h>
#include <assert.h>
#include <fcntl.h>
#include <errno.h>
#include <debug.h>

#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/fs/fat.h>
#include <nuttx/fs/dirent.h>
#include <nuttx/fs/ioctl.h>
#include <nuttx/mtd/mtd.h>
#include <nuttx/fs/smart.h>

#include "smartfs.h"

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

/****************************************************************************
 * Private Types
 ****************************************************************************/

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

static int     smartfs_open(FAR struct file *filep, const char *relpath,
                        int oflags, mode_t mode);
static int     smartfs_close(FAR struct file *filep);
static ssize_t smartfs_read(FAR struct file *filep, char *buffer, size_t buflen);
static ssize_t smartfs_write(FAR struct file *filep, const char *buffer,
                        size_t buflen);
static off_t   smartfs_seek(FAR struct file *filep, off_t offset, int whence);
static int     smartfs_ioctl(FAR struct file *filep, int cmd, unsigned long arg);

static int     smartfs_sync(FAR struct file *filep);
static int     smartfs_dup(FAR const struct file *oldp, FAR struct file *newp);

static int     smartfs_opendir(struct inode *mountpt, const char *relpath,
                        struct fs_dirent_s *dir);
static int     smartfs_readdir(struct inode *mountpt, struct fs_dirent_s *dir);
static int     smartfs_rewinddir(struct inode *mountpt, struct fs_dirent_s *dir);

static int     smartfs_bind(FAR struct inode *blkdriver, const void *data,
                        void **handle);
static int     smartfs_unbind(void *handle, FAR struct inode **blkdriver);
static int     smartfs_statfs(struct inode *mountpt, struct statfs *buf);

static int     smartfs_unlink(struct inode *mountpt, const char *relpath);
static int     smartfs_mkdir(struct inode *mountpt, const char *relpath,
                        mode_t mode);
static int     smartfs_rmdir(struct inode *mountpt, const char *relpath);
static int     smartfs_rename(struct inode *mountpt, const char *oldrelpath,
                        const char *newrelpath);
static int     smartfs_stat(struct inode *mountpt, const char *relpath, struct stat *buf);

static off_t smartfs_seek_internal(struct smartfs_mountpt_s *fs,
                        struct smartfs_ofile_s *sf,
                        off_t offset, int whence);

/****************************************************************************
 * Private Variables
 ****************************************************************************/

static uint8_t  g_seminitialized = FALSE;
static sem_t    g_sem;

/****************************************************************************
 * Public Variables
 ****************************************************************************/

/* See fs_mount.c -- this structure is explicitly externed there.
 * We use the old-fashioned kind of initializers so that this will compile
 * with any compiler.
 */

const struct mountpt_operations smartfs_operations =
{
  smartfs_open,          /* open */
  smartfs_close,         /* close */
  smartfs_read,          /* read */
  smartfs_write,         /* write */
  smartfs_seek,          /* seek */
  smartfs_ioctl,         /* ioctl */

  smartfs_sync,          /* sync */
  smartfs_dup,           /* dup */

  smartfs_opendir,       /* opendir */
  NULL,                  /* closedir */
  smartfs_readdir,       /* readdir */
  smartfs_rewinddir,     /* rewinddir */

  smartfs_bind,          /* bind */
  smartfs_unbind,        /* unbind */
  smartfs_statfs,        /* statfs */

  smartfs_unlink,        /* unlinke */
  smartfs_mkdir,         /* mkdir */
  smartfs_rmdir,         /* rmdir */
  smartfs_rename,        /* rename */
  smartfs_stat           /* stat */
};

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

/****************************************************************************
 * Name: smartfs_open
 ****************************************************************************/

static int smartfs_open(FAR struct file *filep, const char *relpath,
                        int oflags, mode_t mode)
{
  struct inode             *inode;
  struct smartfs_mountpt_s *fs;
  int                       ret;
  uint16_t                  parentdirsector;
  const char               *filename;
  struct smartfs_ofile_s   *sf;

  /* Sanity checks */

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

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

  inode = filep->f_inode;
  fs    = inode->i_private;

  DEBUGASSERT(fs != NULL);

  /* Take the semaphore */

  smartfs_semtake(fs);

  /* Locate the directory entry for this path */

  sf = (struct smartfs_ofile_s *) kmm_malloc(sizeof *sf);
  if (sf == NULL)
    {
      ret = -ENOMEM;
      goto errout_with_semaphore;
    }

  sf->entry.name = NULL;
  ret = smartfs_finddirentry(fs, &sf->entry, relpath, &parentdirsector,
                             &filename);

  /* Three possibililities: (1) a node exists for the relpath and
   * dirinfo describes the directory entry of the entity, (2) the
   * node does not exist, or (3) some error occurred.
   */

  if (ret == OK)
    {
      /* The name exists -- but is is a file or a directory ? */

      if (sf->entry.flags & SMARTFS_DIRENT_TYPE_DIR)
        {
          /* Can't open a dir as a file! */

          ret = -EISDIR;
          goto errout_with_buffer;
        }

      /* 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 */

          ret = -EEXIST;
          goto errout_with_buffer;
        }

      /* TODO: Test open mode based on the file mode */

      /* The file exists.  Check if we are opening it for O_CREAT or
       * O_TRUNC mode and delete the sector chain if we are. */

      if ((oflags & (O_CREAT | O_TRUNC)) != 0)
        {
          /* Don't truncate if open for APPEND */

          if (!(oflags & O_APPEND))
            {
              /* Truncate the file as part of the open */

              ret = smartfs_truncatefile(fs, &sf->entry);
              if (ret < 0)
                {
                  goto errout_with_buffer;
                }
            }
        }
    }
  else if (ret == -ENOENT)
    {
      /* The file does not exist.  Were we asked to create it? */

      if ((oflags & O_CREAT) == 0)
        {
          /* No.. then we fail with -ENOENT */

          ret = -ENOENT;
          goto errout_with_buffer;
        }

      /* Yes... test if the parent directory is valid */

      if (parentdirsector != 0xFFFF)
        {
          /* We can create in the given parent directory */

          ret = smartfs_createentry(fs, parentdirsector, filename,
                                    SMARTFS_DIRENT_TYPE_FILE, mode,
                                    &sf->entry, 0xFFFF);
          if (ret != OK)
            {
              goto errout_with_buffer;
            }
        }
      else
        {
          /* Trying to create in a directory that doesn't exist */

          ret = -ENOENT;
          goto errout_with_buffer;
        }
    }
  else
    {
      goto errout_with_buffer;
    }

  /* Now perform the "open" on the file in direntry */

  sf->oflags = oflags;
  sf->crefs = 1;
  sf->filepos = 0;
  sf->curroffset = sizeof(struct smartfs_chain_header_s);
  sf->currsector = sf->entry.firstsector;
  sf->byteswritten = 0;

  /* Test if we opened for APPEND mode.  If we did, then seek to the
   * end of the file.
   */

  if (oflags & O_APPEND)
    {
      /* Perform the seek */

      smartfs_seek_internal(fs, sf, 0, SEEK_END);
    }

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

  filep->f_priv = sf;

  /* 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).
   */

  sf->fnext = fs->fs_head;
  fs->fs_head = sf;

  ret = OK;
  goto errout_with_semaphore;

errout_with_buffer:
  if (sf->entry.name != NULL)
    {
      /* Free the space for the name too */

      kmm_free(sf->entry.name);
      sf->entry.name = NULL;
    }

  kmm_free(sf);

errout_with_semaphore:
  smartfs_semgive(fs);
  if (ret == -EINVAL)
    {
      ret = -EIO;
    }

  return ret;
}

/****************************************************************************
 * Name: smartfs_close
 ****************************************************************************/

static int smartfs_close(FAR struct file *filep)
{
  struct inode             *inode;
  struct smartfs_mountpt_s *fs;
  struct smartfs_ofile_s   *sf;
  struct smartfs_ofile_s   *nextfile;
  struct smartfs_ofile_s   *prevfile;

  /* Sanity checks */

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

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

  inode = filep->f_inode;
  fs    = inode->i_private;
  sf    = filep->f_priv;

  /* Sync the file */

  smartfs_sync(filep);

  /* Take the semaphore */

  smartfs_semtake(fs);

  /* Check if we are the last one with a reference to the file and
   * only close if we are. */

  if (sf->crefs > 1)
    {
      /* The file is opened more than once.  Just decrement the
       * reference count and return. */

      sf->crefs--;
      goto okout;
    }

  /* Remove ourselves from the linked list */

  nextfile = fs->fs_head;
  prevfile = nextfile;
  while ((nextfile != sf) && (nextfile != NULL))
    {
      /* Save the previous file pointer too */

      prevfile = nextfile;
      nextfile = nextfile->fnext;
    }

  if (nextfile != NULL)
    {
      /* Test if we were the first entry */

      if (nextfile == fs->fs_head)
        {
          /* Assign a new head */

          fs->fs_head = nextfile->fnext;
        }
      else
        {
          /* Take ourselves out of the list */

          prevfile->fnext = nextfile->fnext;
        }
    }

  /* Now free the pointer */

  filep->f_priv = NULL;;
  if (sf->entry.name != NULL)
    {
      /* Free the space for the name too */

      kmm_free(sf->entry.name);
      sf->entry.name = NULL;
    }
  kmm_free(sf);

okout:
  smartfs_semgive(fs);
  return OK;
}

/****************************************************************************
 * Name: smartfs_read
 ****************************************************************************/

static ssize_t smartfs_read(FAR struct file *filep, char *buffer, size_t buflen)
{
  struct inode             *inode;
  struct smartfs_mountpt_s *fs;
  struct smartfs_ofile_s   *sf;
  struct smart_read_write_s readwrite;
  struct smartfs_chain_header_s *header;
  int                       ret = OK;
  uint32_t                  bytesread;
  uint16_t                  bytestoread;
  uint16_t                  bytesinsector;

  /* Sanity checks */

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

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

  sf    = filep->f_priv;
  inode = filep->f_inode;
  fs    = inode->i_private;

  DEBUGASSERT(fs != NULL);

  /* Take the semaphore */

  smartfs_semtake(fs);

  /* Loop until all byte read or error */

  bytesread = 0;
  while (bytesread != buflen)
    {
      /* Test if we are at the end of data */

      if (sf->currsector == SMARTFS_ERASEDSTATE_16BIT)
        {
          /* Break and return the number of bytes we read (may be zero) */

          break;
        }

      /* Read the curent sector into our buffer */

      readwrite.logsector = sf->currsector;
      readwrite.offset = 0;
      readwrite.buffer = (uint8_t *) fs->fs_rwbuffer;
      readwrite.count = fs->fs_llformat.availbytes;
      ret = FS_IOCTL(fs, BIOC_READSECT, (unsigned long) &readwrite);
      if (ret < 0)
        {
          fdbg("Error %d reading sector %d data\n", ret, sf->currsector);
          goto errout_with_semaphore;
        }

      /* Point header to the read data to get used byte count */

      header = (struct smartfs_chain_header_s *) fs->fs_rwbuffer;

      /* Get number of used bytes in this sector */

      bytesinsector = *((uint16_t *) header->used);
      if (bytesinsector == SMARTFS_ERASEDSTATE_16BIT)
        {
          /* No bytes to read from this sector */

          bytesinsector = 0;
        }

      /* Calculate the number of bytes to read into the buffer */

      bytestoread = bytesinsector - (sf->curroffset -
          sizeof(struct smartfs_chain_header_s));
      if (bytestoread + bytesread > buflen)
        {
          /* Truncate bytesto read based on buffer len */

          bytestoread = buflen - bytesread;
        }

      /* Copy data to the read buffer */

      if (bytestoread > 0)
        {
          /* Do incremental copy from this sector */

          memcpy(&buffer[bytesread], &fs->fs_rwbuffer[sf->curroffset], bytestoread);
          bytesread += bytestoread;
          sf->filepos += bytestoread;
          sf->curroffset += bytestoread;
        }

      /* Test if we are at the end of the data in this sector */

      if ((bytestoread == 0) || (sf->curroffset == fs->fs_llformat.availbytes))
        {
          /* Set the next sector as the current sector */

          sf->currsector = SMARTFS_NEXTSECTOR(header);
          sf->curroffset = sizeof(struct smartfs_chain_header_s);

          /* Test if at end of data */

          if (sf->currsector == SMARTFS_ERASEDSTATE_16BIT)
            {
              /* No more data!  Return what we have */

              break;
            }
        }
    }

  /* Return the number of bytes we read */

  ret = bytesread;

errout_with_semaphore:
  smartfs_semgive(fs);
  return ret;
}

/****************************************************************************
 * Name: smartfs_sync_internal
 *
 * Description: Synchronize the file state on disk to match internal, in-
 *   memory state.
 *
 ****************************************************************************/

static int smartfs_sync_internal(struct smartfs_mountpt_s *fs,
                                 struct smartfs_ofile_s *sf)
{
  struct smart_read_write_s readwrite;
  struct smartfs_chain_header_s *header;
  int ret = OK;

  /* Test if we have written bytes to the current sector that
   * need to be recorded in the chain header's used bytes field. */

  if (sf->byteswritten > 0)
    {
      fvdbg("Syncing sector %d\n", sf->currsector);

      /* Read the existing sector used bytes value */

      readwrite.logsector = sf->currsector;
      readwrite.offset = 0;
      readwrite.buffer = (uint8_t *) fs->fs_rwbuffer;
      readwrite.count = sizeof(struct smartfs_chain_header_s);
      ret = FS_IOCTL(fs, BIOC_READSECT, (unsigned long) &readwrite);
      if (ret < 0)
        {
          fdbg("Error %d reading sector %d data\n", ret, sf->currsector);
          goto errout;
        }

      /* Add new byteswritten to existing value */

      header = (struct smartfs_chain_header_s *) fs->fs_rwbuffer;
      if (*((uint16_t *) header->used) == SMARTFS_ERASEDSTATE_16BIT)
        {
          *((uint16_t *) header->used) = sf->byteswritten;
        }
      else
        {
          *((uint16_t *) header->used) += sf->byteswritten;
        }

      readwrite.offset = offsetof(struct smartfs_chain_header_s, used);
      readwrite.count = sizeof(uint16_t);
      readwrite.buffer = (uint8_t *) &fs->fs_rwbuffer[readwrite.offset];
      ret = FS_IOCTL(fs, BIOC_WRITESECT, (unsigned long) &readwrite);
      if (ret < 0)
        {
          fdbg("Error %d writing used bytes for sector %d\n", ret, sf->currsector);
          goto errout;
        }

      sf->byteswritten = 0;
    }

errout:
  return ret;
}

/****************************************************************************
 * Name: smartfs_write
 ****************************************************************************/

static ssize_t smartfs_write(FAR struct file *filep, const char *buffer,
                         size_t buflen)
{
  struct inode             *inode;
  struct smartfs_mountpt_s *fs;
  struct smartfs_ofile_s   *sf;
  struct smart_read_write_s readwrite;
  struct smartfs_chain_header_s *header;
  size_t                    byteswritten;
  int                       ret;

  /* Sanity checks.  I have seen the following assertion misfire if
   * CONFIG_DEBUG_MM is enabled while re-directing output to a
   * file.  In this case, the debug output can get generated while
   * the file is being opened,  FAT data structures are being allocated,
   * and things are generally in a perverse state.
   */

#ifdef CONFIG_DEBUG_MM
  if (filep->f_priv == NULL || filep->f_inode == NULL)
    {
      return -ENXIO;
    }
#else
  DEBUGASSERT(filep->f_priv != NULL && filep->f_inode != NULL);
#endif

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

  sf    = filep->f_priv;
  inode = filep->f_inode;
  fs    = inode->i_private;

  DEBUGASSERT(fs != NULL);

  /* Take the semaphore */

  smartfs_semtake(fs);

  /* Test the permissions.  Only allow write if the file was opened with
   * write flags.
   */

  if ((sf->oflags & O_WROK) == 0)
    {
      ret = -EACCES;
      goto errout_with_semaphore;
    }

  /* First test if we are overwriting an existing location or writing to
   * a new one. */

  header = (struct smartfs_chain_header_s *) fs->fs_rwbuffer;
  byteswritten = 0;
  while ((sf->filepos < sf->entry.datlen) && (buflen > 0))
    {
      /* Overwriting data caused by a seek, etc.  In this case, we need
       * to check if the write causes the file length to be extended
       * or not and update it accordingly.  We will write data up to
       * the current end-of-file and then break, allowing the next while
       * loop below to write the additional data to the end of the file.
       */

      readwrite.offset = sf->curroffset;
      readwrite.logsector = sf->currsector;
      readwrite.buffer = (uint8_t *) &buffer[byteswritten];
      readwrite.count = fs->fs_llformat.availbytes - sf->curroffset;

      /* Limit the write based on available data to write */

      if (readwrite.count > buflen)
        readwrite.count = buflen;

      /* Limit the write based on current file length */

      if (readwrite.count > sf->entry.datlen - sf->filepos)
        {
          /* Limit the write length so we write to the current EOF. */

          readwrite.count = sf->entry.datlen - sf->filepos;
        }

      /* Now perform the write. */

      if (readwrite.count > 0)
        {
          ret = FS_IOCTL(fs, BIOC_WRITESECT, (unsigned long) &readwrite);
          if (ret < 0)
            {
              fdbg("Error %d writing sector %d data\n", ret, sf->currsector);
              goto errout_with_semaphore;
            }

          /* Update our control variables */

          sf->filepos += readwrite.count;
          sf->curroffset += readwrite.count;
          buflen -= readwrite.count;
          byteswritten += readwrite.count;
        }

      /* Test if we wrote to the end of the current sector */

      if (sf->curroffset == fs->fs_llformat.availbytes)
        {
          /* Wrote to the end of the sector.  Update to point to the
           * next sector for additional writes.  First read the sector
           * header to get the sector chain info.
           */

          readwrite.offset = 0;
          readwrite.buffer = (uint8_t *) fs->fs_rwbuffer;
          readwrite.count = sizeof(struct smartfs_chain_header_s);
          ret = FS_IOCTL(fs, BIOC_READSECT, (unsigned long) &readwrite);
          if (ret < 0)
            {
              fdbg("Error %d reading sector %d header\n", ret, sf->currsector);
              goto errout_with_semaphore;
            }

          /* Now get the chained sector info and reset the offset */

          sf->curroffset = sizeof(struct smartfs_chain_header_s);
          sf->currsector = SMARTFS_NEXTSECTOR(header);
        }
    }

  /* Now append data to end of the file. */

  while (buflen > 0)
    {
      /* We will fill up the current sector. Write data to
       * the current sector first.
       */

      readwrite.offset = sf->curroffset;
      readwrite.logsector = sf->currsector;
      readwrite.buffer = (uint8_t *) &buffer[byteswritten];
      readwrite.count = fs->fs_llformat.availbytes - sf->curroffset;
      if (readwrite.count > buflen)
        {
          /* Limit the write base on remaining bytes to write */

          readwrite.count = buflen;
        }

      /* Perform the write */

      if (readwrite.count > 0)
        {
          ret = FS_IOCTL(fs, BIOC_WRITESECT, (unsigned long) &readwrite);
          if (ret < 0)
            {
              fdbg("Error %d writing sector %d data\n", ret, sf->currsector);
              goto errout_with_semaphore;
            }

          /* Update our control variables */

          sf->entry.datlen += readwrite.count;
          sf->byteswritten += readwrite.count;
          sf->filepos += readwrite.count;
          sf->curroffset += readwrite.count;
          buflen -= readwrite.count;
          byteswritten += readwrite.count;
        }

      /* Test if we wrote a full sector of data */

      if (sf->curroffset == fs->fs_llformat.availbytes)
        {
          /* Sync the file to write this sector out */

          smartfs_sync_internal(fs, sf);

          /* Allocate a new sector if needed */

          if (buflen > 0)
            {
              /* Allocate a new sector */

              ret = FS_IOCTL(fs, BIOC_ALLOCSECT, 0xFFFF);
              if (ret < 0)
                {
                  fdbg("Error %d allocating new sector\n", ret);
                  goto errout_with_semaphore;
                }

              /* Copy the new sector to the old one and chain it */

              header = (struct smartfs_chain_header_s *) fs->fs_rwbuffer;
              *((uint16_t *) header->nextsector) = (uint16_t) ret;
              readwrite.offset = offsetof(struct smartfs_chain_header_s,
                nextsector);
              readwrite.buffer = (uint8_t *) header->nextsector;
              readwrite.count = sizeof(uint16_t);
              ret = FS_IOCTL(fs, BIOC_WRITESECT, (unsigned long) &readwrite);
              if (ret < 0)
                {
                  fdbg("Error %d writing next sector\n", ret);
                  goto errout_with_semaphore;
                }

              /* Record the new sector in our tracking variables and
               * reset the offset to "zero".
               */

              sf->currsector = SMARTFS_NEXTSECTOR(header);
              sf->curroffset = sizeof(struct smartfs_chain_header_s);
            }
        }
    }

  ret = byteswritten;

errout_with_semaphore:
  smartfs_semgive(fs);
  return ret;
}

/****************************************************************************
 * Name: smartfs_seek_internal
 *
 * Description: Performs the logic of the seek function.  This is an internal
 *              function because it does not provide semaphore protection and
 *              therefore must be called from one of the other public
 *              interface routines (open, seek, etc.).
 *
 ****************************************************************************/

static off_t smartfs_seek_internal(struct smartfs_mountpt_s *fs,
                                   struct smartfs_ofile_s *sf,
                                   off_t offset, int whence)
{
  struct smart_read_write_s readwrite;
  struct smartfs_chain_header_s *header;
  int                       ret;
  off_t                     newpos;
  off_t                     sectorstartpos;

  /* Test if this is a seek to get the current file pos */

  if ((whence == SEEK_CUR) && (offset == 0))
    {
      return sf->filepos;
    }

  /* Test if we need to sync the file */

  if (sf->byteswritten > 0)
    {
      /* Perform a sync */

      smartfs_sync_internal(fs, sf);
    }

  /* Calculate the file position to seek to based on current position */

  switch (whence)
  {
    case SEEK_SET:
    default:
      newpos = offset;
      break;

    case SEEK_CUR:
      newpos = sf->filepos + offset;
      break;

    case SEEK_END:
      newpos = sf->entry.datlen - offset;
      break;
  }

  /* Ensure newpos is in range */

  if (newpos < 0)
    {
      newpos = 0;
    }

  if (newpos > sf->entry.datlen)
    {
      newpos = sf->entry.datlen;
    }

  /* Now perform the seek.  Test if we are seeking within the current
   * sector and can skip the search to save time.
   */

  sectorstartpos = sf->filepos - (sf->curroffset - sizeof(struct
        smartfs_chain_header_s));
  if (newpos >= sectorstartpos && newpos < sectorstartpos +
      fs->fs_llformat.availbytes - sizeof(struct smartfs_chain_header_s))
    {
      /* Seeking within the current sector.  Just update the offset */

      sf->curroffset = sizeof(struct smartfs_chain_header_s) + newpos-sectorstartpos;
      sf->filepos = newpos;

      return newpos;
    }

  /* Nope, we have to search for the sector and offset.  If the new pos is greater
   * than the current pos, then we can start from the beginning of the current
   * sector, otherwise we have to start from the beginning of the file.
   */

  if (newpos > sf->filepos)
    {
      sf->filepos = sectorstartpos;
    }
  else
    {
      sf->currsector = sf->entry.firstsector;
      sf->filepos = 0;
    }

  header = (struct smartfs_chain_header_s *) fs->fs_rwbuffer;
  while ((sf->currsector != SMARTFS_ERASEDSTATE_16BIT) &&
      (sf->filepos + fs->fs_llformat.availbytes -
      sizeof(struct smartfs_chain_header_s) < newpos))
    {
      /* Read the sector's header */

      readwrite.logsector = sf->currsector;
      readwrite.offset = 0;
      readwrite.count = sizeof(struct smartfs_chain_header_s);
      readwrite.buffer = (uint8_t *) fs->fs_rwbuffer;
      ret = FS_IOCTL(fs, BIOC_READSECT, (unsigned long) &readwrite);
      if (ret < 0)
        {
          fdbg("Error %d reading sector %d header\n", ret, sf->currsector);
          goto errout;
        }

      /* Point to next sector and update filepos */

      sf->currsector = SMARTFS_NEXTSECTOR(header);
      sf->filepos += SMARTFS_USED(header);
    }

  /* Now calculate the offset */

  sf->curroffset = sizeof(struct smartfs_chain_header_s) + newpos - sf->filepos;
  sf->filepos = newpos;
  return newpos;

errout:
  return ret;
}

/****************************************************************************
 * Name: smartfs_seek
 ****************************************************************************/

static off_t smartfs_seek(FAR struct file *filep, off_t offset, int whence)
{
  struct inode             *inode;
  struct smartfs_mountpt_s *fs;
  struct smartfs_ofile_s   *sf;
  int                       ret;

  /* Sanity checks */

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

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

  sf    = filep->f_priv;
  inode = filep->f_inode;
  fs    = inode->i_private;

  DEBUGASSERT(fs != NULL);

  /* Take the semaphore */

  smartfs_semtake(fs);

  /* Call our internal routine to perform the seek */

  ret = smartfs_seek_internal(fs, sf, offset, whence);

  if (ret >= 0)
    {
      filep->f_pos = ret;
    }

  smartfs_semgive(fs);
  return ret;
}

/****************************************************************************
 * Name: smartfs_ioctl
 ****************************************************************************/

static int smartfs_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
  /* We don't use any ioctls */

  return -ENOSYS;
}

/****************************************************************************
 * Name: smartfs_sync
 *
 * Description: Synchronize the file state on disk to match internal, in-
 *   memory state.
 *
 ****************************************************************************/

static int smartfs_sync(FAR struct file *filep)
{
  struct inode             *inode;
  struct smartfs_mountpt_s *fs;
  struct smartfs_ofile_s   *sf;
  int                       ret;

  /* Sanity checks */

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

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

  sf    = filep->f_priv;
  inode = filep->f_inode;
  fs    = inode->i_private;

  DEBUGASSERT(fs != NULL);

  /* Take the semaphore */

  smartfs_semtake(fs);

  ret = smartfs_sync_internal(fs, sf);

  smartfs_semgive(fs);
  return ret;
}

/****************************************************************************
 * Name: smart_dup
 *
 * Description: Duplicate open file data in the new file structure.
 *
 ****************************************************************************/

static int smartfs_dup(FAR const struct file *oldp, FAR struct file *newp)
{
  struct smartfs_ofile_s   *sf;

  fvdbg("Dup %p->%p\n", oldp, newp);

  /* Sanity checks */

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

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

  sf    = oldp->f_priv;

  DEBUGASSERT(sf != NULL);

  /* Just increment the reference count on the ofile */

  sf->crefs++;
  newp->f_priv = (FAR void *)sf;

  return OK;
}

/****************************************************************************
 * Name: smartfs_opendir
 *
 * Description: Open a directory for read access
 *
 ****************************************************************************/

static int smartfs_opendir(struct inode *mountpt, const char *relpath, struct fs_dirent_s *dir)
{
  struct smartfs_mountpt_s *fs;
  int                       ret;
  struct smartfs_entry_s    entry;
  uint16_t                  parentdirsector;
  const char               *filename;

  /* Sanity checks */

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

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

  fs = mountpt->i_private;

  /* Take the semaphore */

  smartfs_semtake(fs);

  /* Search for the path on the volume */

  entry.name = NULL;
  ret = smartfs_finddirentry(fs, &entry, relpath, &parentdirsector,
                             &filename);
  if (ret < 0)
    {
      goto errout_with_semaphore;
    }

  /* Populate our private data in the fs_dirent_s struct */

  dir->u.smartfs.fs_firstsector = entry.firstsector;
  dir->u.smartfs.fs_currsector = entry.firstsector;
  dir->u.smartfs.fs_curroffset = sizeof(struct smartfs_chain_header_s);

  ret = OK;

errout_with_semaphore:
  /* If space for the entry name was allocated, then free it */

  if (entry.name != NULL)
    {
        kmm_free(entry.name);
        entry.name = NULL;
    }

  smartfs_semgive(fs);
  return ret;
}

/****************************************************************************
 * Name: smartfs_readdir
 *
 * Description: Read the next directory entry
 *
 ****************************************************************************/

static int smartfs_readdir(struct inode *mountpt, struct fs_dirent_s *dir)
{
  struct smartfs_mountpt_s *fs;
  int                   ret;
  uint16_t              entrysize;
  uint16_t              namelen;
  struct                smartfs_chain_header_s *header;
  struct                smart_read_write_s readwrite;
  struct                smartfs_entry_header_s *entry;

  /* Sanity checks */

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

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

  fs = mountpt->i_private;

  /* Take the semaphore */

  smartfs_semtake(fs);

  /* Read sectors and search entries until one found or no more */

  entrysize = sizeof(struct smartfs_entry_header_s) +
    fs->fs_llformat.namesize;
  while (dir->u.smartfs.fs_currsector != SMARTFS_ERASEDSTATE_16BIT)
    {
      /* Read the logical sector */

      readwrite.logsector = dir->u.smartfs.fs_currsector;
      readwrite.count = fs->fs_llformat.availbytes;
      readwrite.buffer = (uint8_t *)fs->fs_rwbuffer;
      readwrite.offset = 0;
      ret = FS_IOCTL(fs, BIOC_READSECT, (unsigned long) &readwrite);
      if (ret < 0)
        {
          goto errout_with_semaphore;
        }

      /* Now search for entries, starting at curroffset */

      while (dir->u.smartfs.fs_curroffset < ret)
        {
          /* Point to next entry */

          entry = (struct smartfs_entry_header_s *) &fs->fs_rwbuffer[
            dir->u.smartfs.fs_curroffset];

          /* Test if this entry is valid and active */

          if (((entry->flags & SMARTFS_DIRENT_EMPTY) ==
              (SMARTFS_ERASEDSTATE_16BIT & SMARTFS_DIRENT_EMPTY)) ||
              ((entry->flags & SMARTFS_DIRENT_ACTIVE) !=
              (SMARTFS_ERASEDSTATE_16BIT & SMARTFS_DIRENT_ACTIVE)))
            {
              /* This entry isn't valid, skip it */

              dir->u.smartfs.fs_curroffset += entrysize;
              entry = (struct smartfs_entry_header_s *)
                &fs->fs_rwbuffer[dir->u.smartfs.fs_curroffset];

              continue;
            }

          /* Entry found!  Report it */

          if ((entry->flags & SMARTFS_DIRENT_TYPE) == SMARTFS_DIRENT_TYPE_DIR)
            {
              dir->fd_dir.d_type = DTYPE_DIRECTORY;
            }
          else
            {
              dir->fd_dir.d_type = DTYPE_FILE;
            }

          /* Copy the entry name to dirent */

          namelen = fs->fs_llformat.namesize;
          if (namelen > NAME_MAX)
            {
              namelen = NAME_MAX;
            }

          memset(dir->fd_dir.d_name, 0, namelen);
          strncpy(dir->fd_dir.d_name, entry->name, namelen);

          /* Now advance to the next entry */

          dir->u.smartfs.fs_curroffset += entrysize;
          if (dir->u.smartfs.fs_curroffset >= fs->fs_llformat.availbytes)
            {
              /* We advanced past the end of the sector.  Go to next sector */

              dir->u.smartfs.fs_curroffset = sizeof(struct smartfs_chain_header_s);
              header = (struct smartfs_chain_header_s *) fs->fs_rwbuffer;
              dir->u.smartfs.fs_currsector = SMARTFS_NEXTSECTOR(header);
            }

          /* Now exit */

          ret = OK;
          goto errout_with_semaphore;
        }

      /* No more entries in this sector.  Move on to next sector and
       * continue the search.  If no more sectors, then we are all
       * done and will report ENOENT.
       */

      header = (struct smartfs_chain_header_s *) fs->fs_rwbuffer;
      dir->u.smartfs.fs_curroffset = sizeof(struct smartfs_chain_header_s);
      dir->u.smartfs.fs_currsector = SMARTFS_NEXTSECTOR(header);
    }

  /* If we arrive here, then there are no more entries */

  ret = -ENOENT;

errout_with_semaphore:
  smartfs_semgive(fs);
  return ret;
}

/****************************************************************************
 * Name: smartfs_rewindir
 *
 * Description: Reset directory read to the first entry
 *
 ****************************************************************************/

static int smartfs_rewinddir(struct inode *mountpt, struct fs_dirent_s *dir)
{
  int ret = OK;

  /* Sanity checks */

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

  /* Reset the directory to the first entry */

  dir->u.smartfs.fs_currsector = dir->u.smartfs.fs_firstsector;
  dir->u.smartfs.fs_curroffset = sizeof(struct smartfs_chain_header_s);

  return ret;
}

/****************************************************************************
 * Name: smartfs_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().
 *
 ****************************************************************************/

static int smartfs_bind(FAR struct inode *blkdriver, const void *data,
                        void **handle)
{
  struct smartfs_mountpt_s *fs;
  int ret;

  /* Open the block driver */

  if (!blkdriver || !blkdriver->u.i_bops)
    {
      return -ENODEV;
    }

  if (blkdriver->u.i_bops->open &&
      blkdriver->u.i_bops->open(blkdriver) != OK)
    {
      return -ENODEV;
    }

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

  fs = (struct smartfs_mountpt_s *)kmm_zalloc(sizeof(struct smartfs_mountpt_s));
  if (!fs)
    {
      return -ENOMEM;
    }

  /* If the global semaphore hasn't been initialized, then
   * initialized it now. */

  fs->fs_sem = &g_sem;
  if (!g_seminitialized)
    {
      sem_init(&g_sem, 0, 0);   /* Initialize the semaphore that controls access */
      g_seminitialized = TRUE;
    }
  else
    {
      /* Take the semaphore for the mount */

      smartfs_semtake(fs);
    }

  /* Initialize the allocated mountpt state structure.  The filesystem is
   * responsible for one reference ont the blkdriver inode and does not
   * have to addref() here (but does have to release in ubind().
   */

  fs->fs_blkdriver = blkdriver;  /* Save the block driver reference */
  fs->fs_head = NULL;

  /* Now perform the mount.  */

  ret = smartfs_mount(fs, true);
  if (ret != 0)
    {
      kmm_free(fs);
      smartfs_semgive(fs);
      return ret;
    }

  *handle = (void*)fs;
  smartfs_semgive(fs);
  return OK;
}

/****************************************************************************
 * Name: smartfs_unbind
 *
 * Description: This implements the filesystem portion of the umount
 *   operation.
 *
 ****************************************************************************/

static int smartfs_unbind(void *handle, FAR struct inode **blkdriver)
{
  struct smartfs_mountpt_s *fs = (struct smartfs_mountpt_s*)handle;
  int ret;

  if (!fs)
    {
      return -EINVAL;
    }

  /* Check if there are sill any files opened on the filesystem. */

  ret = OK; /* Assume success */
  smartfs_semtake(fs);
  if (fs->fs_head != NULL)
    {
      /* We cannot unmount now.. there are open files */

      smartfs_semgive(fs);

      ret = -EBUSY;
    }
  else
    {
       /* Unmount ... close the block driver */

      ret = smartfs_unmount(fs);
    }

  smartfs_semgive(fs);
  kmm_free(fs);

  return ret;
}

/****************************************************************************
 * Name: smartfs_statfs
 *
 * Description: Return filesystem statistics
 *
 ****************************************************************************/

static int smartfs_statfs(struct inode *mountpt, struct statfs *buf)
{
  struct smartfs_mountpt_s *fs;
  int ret;

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

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

  fs = mountpt->i_private;

  smartfs_semtake(fs);

  /* Implement the logic!! */

  memset(buf, 0, sizeof(struct statfs));
  buf->f_type = SMARTFS_MAGIC;

  /* Re-request the low-level format info to update free blocks */

  ret = FS_IOCTL(fs, BIOC_GETFORMAT, (unsigned long) &fs->fs_llformat);

  buf->f_namelen = fs->fs_llformat.namesize;
  buf->f_bsize = fs->fs_llformat.sectorsize;
  buf->f_blocks = fs->fs_llformat.nsectors;
  buf->f_bfree = fs->fs_llformat.nfreesectors;
  buf->f_bavail = fs->fs_llformat.nfreesectors;
  buf->f_files = 0;
  buf->f_ffree = fs->fs_llformat.nfreesectors;

  smartfs_semgive(fs);
  return ret;
}

/****************************************************************************
 * Name: smartfs_unlink
 *
 * Description: Remove a file
 *
 ****************************************************************************/

static int smartfs_unlink(struct inode *mountpt, const char *relpath)
{
  struct smartfs_mountpt_s *fs;
  int                       ret;
  struct smartfs_entry_s    entry;
  const char               *filename;
  uint16_t                  parentdirsector;

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

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

  fs = mountpt->i_private;

  smartfs_semtake(fs);

  /* Locate the directory entry for this path */

  entry.name = NULL;
  ret = smartfs_finddirentry(fs, &entry, relpath, &parentdirsector,
                             &filename);

  if (ret == OK)
    {
      /* The name exists -- validate it is a file, not a dir */

      if ((entry.flags & SMARTFS_DIRENT_TYPE) == SMARTFS_DIRENT_TYPE_DIR)
        {
          ret = -EISDIR;
          goto errout_with_semaphore;
        }

      /* TODO:  Need to check permissions?  */

      /* Okay, we are clear to delete the file.  Use the deleteentry routine. */

      smartfs_deleteentry(fs, &entry);

    }
  else
    {
      /* Just report the error */

      goto errout_with_semaphore;
    }

  ret = OK;

errout_with_semaphore:
  smartfs_semgive(fs);
  return ret;
}

/****************************************************************************
 * Name: smartfs_mkdir
 *
 * Description: Create a directory
 *
 ****************************************************************************/

static int smartfs_mkdir(struct inode *mountpt, const char *relpath, mode_t mode)
{
  struct smartfs_mountpt_s *fs;
  int                       ret;
  struct smartfs_entry_s    entry;
  uint16_t                  parentdirsector;
  const char               *filename;

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

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

  fs = mountpt->i_private;

  smartfs_semtake(fs);

  /* Locate the directory entry for this path */

  entry.name = NULL;
  ret = smartfs_finddirentry(fs, &entry, relpath, &parentdirsector,
                             &filename);

  /* Three possibililities: (1) a node exists for the relpath and
   * dirinfo describes the directory entry of the entity, (2) the
   * node does not exist, or (3) some error occurred.
   */

  if (ret == OK)
    {
      /* The name exists -- can't create */

      ret = -EEXIST;
      goto errout_with_semaphore;
    }
  else if (ret == -ENOENT)
    {
      /* It doesn't exist ... we can create it, but only if we have
       * the right permissions and if the parentdirsector is valid. */

      if (parentdirsector == 0xFFFF)
        {
          /* Invalid entry in the path (non-existant dir segment) */

          goto errout_with_semaphore;
        }

      /* Check mode */

      /* Create the directory */

      ret = smartfs_createentry(fs, parentdirsector, filename,
          SMARTFS_DIRENT_TYPE_DIR, mode, &entry, 0xFFFF);
      if (ret != OK)
        {
          goto errout_with_semaphore;
        }

      ret = OK;
    }

errout_with_semaphore:
  if (entry.name != NULL)
    {
      /* Free the filename space allocation */

      kmm_free(entry.name);
      entry.name = NULL;
    }

  smartfs_semgive(fs);
  return ret;
}

/****************************************************************************
 * Name: smartfs_rmdir
 *
 * Description: Remove a directory
 *
 ****************************************************************************/

int smartfs_rmdir(struct inode *mountpt, const char *relpath)
{
  struct smartfs_mountpt_s *fs;
  int                       ret;
  struct smartfs_entry_s    entry;
  const char               *filename;
  uint16_t                  parentdirsector;

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

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

  fs = mountpt->i_private;

  /* Take the semaphore */

  smartfs_semtake(fs);

  /* Locate the directory entry for this path */

  entry.name = NULL;
  ret = smartfs_finddirentry(fs, &entry, relpath, &parentdirsector,
                             &filename);

  if (ret == OK)
    {
      /* The name exists -- validate it is a dir, not a file */

      if ((entry.flags & SMARTFS_DIRENT_TYPE) == SMARTFS_DIRENT_TYPE_FILE)
        {
          ret = -ENOTDIR;
          goto errout_with_semaphore;
        }

      /* TODO:  Need to check permissions?  */

      /* Check if the directory is emtpy */

      ret = smartfs_countdirentries(fs, &entry);
      if (ret < 0)
        {
          goto errout_with_semaphore;
        }

      /* Only continue if there are zero entries in the directory */

      if (ret != 0)
        {
          ret = -ENOTEMPTY;
          goto errout_with_semaphore;
        }

      /* Okay, we are clear to delete the directory.  Use the deleteentry routine. */

      ret = smartfs_deleteentry(fs, &entry);
      if (ret < 0)
        {
          goto errout_with_semaphore;
        }
    }
  else
    {
      /* Just report the error */

      goto errout_with_semaphore;
    }

  ret = OK;

errout_with_semaphore:
  smartfs_semgive(fs);
  return ret;
}

/****************************************************************************
 * Name: smartfs_rename
 *
 * Description: Rename a file or directory
 *
 ****************************************************************************/

int smartfs_rename(struct inode *mountpt, const char *oldrelpath,
               const char *newrelpath)
{
  struct smartfs_mountpt_s *fs;
  int                       ret;
  struct smartfs_entry_s    oldentry;
  uint16_t                  oldparentdirsector;
  const char               *oldfilename;
  struct smartfs_entry_s    newentry;
  uint16_t                  newparentdirsector;
  const char               *newfilename;
  mode_t                    mode;
  uint16_t                  type;
  uint16_t                  sector;
  uint16_t                  offset;
  uint16_t                  entrysize;
  struct smartfs_entry_header_s *direntry;
  struct smart_read_write_s readwrite;

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

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

  fs = mountpt->i_private;

  smartfs_semtake(fs);

  /* Search for old entry to validate it exists */

  oldentry.name = NULL;
  newentry.name = NULL;
  ret = smartfs_finddirentry(fs, &oldentry, oldrelpath, &oldparentdirsector,
          &oldfilename);
  if (ret < 0)
    {
      goto errout_with_semaphore;
    }

  /* Search for the new entry and validate it DOESN'T exist, unless we
   * are copying to a directory and keeping the same filename, such as:
   *
   *    mv /mntpoint/somefile.txt /mntpoint/somedir
   *
   * in which case, we need to validate the /mntpoint/somedir/somefile.txt
   * doens't exsit.
   */

  ret = smartfs_finddirentry(fs, &newentry, newrelpath, &newparentdirsector,
          &newfilename);
  if (ret == OK)
    {
      /* Test if it's a file.  If it is, then it's an error */

      if ((newentry.flags & SMARTFS_DIRENT_TYPE) == SMARTFS_DIRENT_TYPE_FILE)
        {
          ret = -EEXIST;
          goto errout_with_semaphore;
        }

      /* Nope, it's a directory.  Now search the directory for oldfilename */

      sector = newentry.firstsector;
      while (sector != SMARTFS_ERASEDSTATE_16BIT)
        {
          /* Read the next sector of diretory entries */

          readwrite.logsector = sector;
          readwrite.offset = 0;
          readwrite.count = fs->fs_llformat.availbytes;
          readwrite.buffer = (uint8_t *) fs->fs_rwbuffer;
          ret = FS_IOCTL(fs, BIOC_READSECT, (unsigned long) &readwrite);
          if (ret < 0)
            {
              fdbg("Error %d reading sector %d data\n", ret, oldentry.dsector);
              goto errout_with_semaphore;
            }

          /* Search for newfilename in this sector */

          offset = sizeof(struct smartfs_chain_header_s);
          entrysize = sizeof(struct smartfs_entry_header_s) + fs->fs_llformat.namesize;
          while (offset + entrysize < fs->fs_llformat.availbytes)
            {
              /* Test the next entry */

              direntry = (struct smartfs_entry_header_s *) &fs->fs_rwbuffer[offset];
              if (((direntry->flags & SMARTFS_DIRENT_EMPTY) ==
                  (SMARTFS_ERASEDSTATE_16BIT & SMARTFS_DIRENT_EMPTY)) ||
                  ((direntry->flags & SMARTFS_DIRENT_ACTIVE) !=
                  (SMARTFS_ERASEDSTATE_16BIT & SMARTFS_DIRENT_ACTIVE)))
                {
                  /* This entry isn't valid, skip it */

                  offset += entrysize;
                  continue;
                }

              /* Test if this entry matches newfilename */

              if (strcmp(newfilename, direntry->name) == 0)
                {
                  /* Uh-oh, looks like the entry already exists */

                  ret = -EEXIST;
                  goto errout_with_semaphore;
                }

              offset += entrysize;
            }

          /* Chain to next sector */

          sector = SMARTFS_NEXTSECTOR(((struct smartfs_chain_header_s *)fs->fs_rwbuffer));
        }

      /* Okay, we will create newfilename in the newentry directory */

      newparentdirsector = newentry.firstsector;
      newfilename = oldfilename;
    }

  /* Test if the new parent directory is valid */

  if (newparentdirsector != 0xFFFF)
    {
      /* We can move to the given parent directory */

      mode = oldentry.flags & SMARTFS_DIRENT_MODE;
      type = oldentry.flags & SMARTFS_DIRENT_TYPE;
      ret = smartfs_createentry(fs, newparentdirsector, newfilename,
                                type, mode, &newentry, oldentry.firstsector);
      if (ret != OK)
        {
          goto errout_with_semaphore;
        }

      /* Now mark the old entry as inactive */

      readwrite.logsector = oldentry.dsector;
      readwrite.offset = 0;
      readwrite.count = fs->fs_llformat.availbytes;
      readwrite.buffer = (uint8_t *) fs->fs_rwbuffer;
      ret = FS_IOCTL(fs, BIOC_READSECT, (unsigned long) &readwrite);
      if (ret < 0)
        {
          fdbg("Error %d reading sector %d data\n", ret, oldentry.dsector);
          goto errout_with_semaphore;
        }

      direntry = (struct smartfs_entry_header_s *) &fs->fs_rwbuffer[oldentry.doffset];
#if CONFIG_SMARTFS_ERASEDSTATE == 0xFF
      direntry->flags &= ~SMARTFS_DIRENT_ACTIVE;
#else
      direntry->flags |= SMARTFS_DIRENT_ACTIVE;
#endif

      /* Now write the updated flags back to the device */

      readwrite.offset = oldentry.doffset;
      readwrite.count = sizeof(direntry->flags);
      readwrite.buffer = (uint8_t *) &direntry->flags;
      ret = FS_IOCTL(fs, BIOC_WRITESECT, (unsigned long) &readwrite);
      if (ret < 0)
        {
          fdbg("Error %d writing flag bytes for sector %d\n", ret, readwrite.logsector);
          goto errout_with_semaphore;
        }
    }
  else
    {
      /* Trying to create in a directory that doesn't exist */

      ret = -ENOENT;
      goto errout_with_semaphore;
    }

  ret = OK;

errout_with_semaphore:
  if (oldentry.name != NULL)
    {
      kmm_free(oldentry.name);
      oldentry.name = NULL;
    }

  if (newentry.name != NULL)
    {
      kmm_free(newentry.name);
      newentry.name = NULL;
    }

  smartfs_semgive(fs);
  return ret;
}

/****************************************************************************
 * Name: smartfs_stat
 *
 * Description: Return information about a file or directory
 *
 ****************************************************************************/

static int smartfs_stat(struct inode *mountpt, const char *relpath, struct stat *buf)
{
  struct smartfs_mountpt_s *fs;
  struct smartfs_entry_s    entry;
  int                       ret;
  uint16_t                  parentdirsector;
  const char               *filename;

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

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

  fs = mountpt->i_private;

  smartfs_semtake(fs);

  /* Find the directory entry corresponding to relpath */

  entry.name = NULL;
  ret = smartfs_finddirentry(fs, &entry, relpath, &parentdirsector,
                             &filename);
  if (ret < 0)
    {
      goto errout_with_semaphore;
    }

  /* Initialize the stat structure */

  memset(buf, 0, sizeof(struct stat));
  if (entry.firstsector == fs->fs_rootsector)
    {
      /* It's directory name of the mount point */

      buf->st_mode = S_IFDIR|S_IROTH|S_IRGRP|S_IRUSR|S_IWOTH|S_IWGRP|S_IWUSR;
      ret = OK;
      goto errout_with_semaphore;
    }

  buf->st_mode = entry.flags & 0xFFF;
  if ((entry.flags & SMARTFS_DIRENT_TYPE) == SMARTFS_DIRENT_TYPE_DIR)
    {
      buf->st_mode |= S_IFDIR;
    }
  else
    {
      buf->st_mode |= S_IFREG;
    }

  buf->st_size      = entry.datlen;
  buf->st_blksize   = fs->fs_llformat.availbytes;
  buf->st_blocks    = (buf->st_size + buf->st_blksize - 1) / buf->st_blksize;
  buf->st_atime     = 0;
  buf->st_ctime     = 0;

  ret = OK;

errout_with_semaphore:
  if (entry.name != NULL)
    {
      kmm_free(entry.name);
      entry.name = NULL;
    }

  smartfs_semgive(fs);
  return ret;
}

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