nuttx/fs/smartfs/smartfs_smart.c

/****************************************************************************
 * fs/smartfs/smartfs_smart.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * 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 <assert.h>
#include <fcntl.h>
#include <errno.h>
#include <debug.h>

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

#include "smartfs.h"

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

struct smartfs_dir_s
{
  struct fs_dirent_s fs_base; /* VFS directory structure */
  uint16_t fs_firstsector;    /* First sector of directory list */
  uint16_t fs_currsector;     /* Current sector of directory list */
  uint16_t fs_curroffset;     /* Current offset within current sector */
};

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

static int     smartfs_open(FAR struct file *filep, FAR 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, FAR char *buffer,
                        size_t buflen);
static ssize_t smartfs_write(FAR struct file *filep, FAR 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_fstat(FAR const struct file *filep,
                        FAR struct stat *buf);
static int     smartfs_truncate(FAR struct file *filep, off_t length);

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

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

static int     smartfs_unlink(FAR struct inode *mountpt,
                        FAR const char *relpath);
static int     smartfs_mkdir(FAR struct inode *mountpt,
                        FAR const char *relpath,
                        mode_t mode);
static int     smartfs_rmdir(FAR struct inode *mountpt,
                        FAR const char *relpath);
static int     smartfs_rename(FAR struct inode *mountpt,
                        FAR const char *oldrelpath,
                        FAR const char *newrelpath);
static void    smartfs_stat_common(FAR struct smartfs_mountpt_s *fs,
                        FAR struct smartfs_entry_s *entry,
                        FAR struct stat *buf);
static int     smartfs_stat(FAR struct inode *mountpt,
                        FAR const char *relpath,
                        FAR struct stat *buf);

/****************************************************************************
 * Private Data
 ****************************************************************************/

static mutex_t g_lock = NXMUTEX_INITIALIZER;

/****************************************************************************
 * Public Data
 ****************************************************************************/

/* 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 g_smartfs_operations =
{
  smartfs_open,          /* open */
  smartfs_close,         /* close */
  smartfs_read,          /* read */
  smartfs_write,         /* write */
  smartfs_seek,          /* seek */
  smartfs_ioctl,         /* ioctl */
  NULL,                  /* mmap */
  smartfs_truncate,      /* truncate */

  smartfs_sync,          /* sync */
  smartfs_dup,           /* dup */
  smartfs_fstat,         /* fstat */
  NULL,                  /* fchstat */

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

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

  smartfs_unlink,        /* unlink */
  smartfs_mkdir,         /* mkdir */
  smartfs_rmdir,         /* rmdir */
  smartfs_rename,        /* rename */
  smartfs_stat,          /* stat */
  NULL                   /* chstat */
};

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

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

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

  /* 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 lock */

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return ret;
    }

  /* Locate the directory entry for this path */

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

  /* Allocate a sector buffer if CRC enabled in the MTD layer */

#ifdef CONFIG_SMARTFS_USE_SECTOR_BUFFER
  sf->buffer = kmm_malloc(fs->fs_llformat.availbytes);
  if (sf->buffer == NULL)
    {
      /* Error ... no memory */

      kmm_free(sf);
      ret = -ENOMEM;
      goto errout_with_lock;
    }

  sf->bflags = 0;
#endif /* CONFIG_SMARTFS_USE_SECTOR_BUFFER */

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

  /* Three possibilities: (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 */

      /* If O_TRUNC is specified and the file is opened for writing,
       * then truncate the file.  This operation requires that the file
       * is writeable. O_TRUNC without write access is ignored.
       */

      if ((oflags & (O_TRUNC | O_WROK)) == (O_TRUNC | O_WROK))
        {
          /* Truncate the file as part of the open */

          ret = smartfs_shrinkfile(fs, sf, 0);
          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, sf);
          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;

#ifdef CONFIG_SMARTFS_USE_SECTOR_BUFFER

  /* When using sector buffering, current sector with its header should
   * always be present in sf->buffer. Otherwise data corruption may arise
   * when writing.
   */

  if (sf->currsector != SMARTFS_ERASEDSTATE_16BIT)
    {
      readwrite.logsector = sf->currsector;
      readwrite.offset    = 0;
      readwrite.count     = fs->fs_llformat.availbytes;
      readwrite.buffer    = (FAR uint8_t *)sf->buffer;

      ret = FS_IOCTL(fs, BIOC_READSECT, (unsigned long)&readwrite);
      if (ret < 0)
        {
          ferr("ERROR: Error %d reading sector %d header\n",
               ret, sf->currsector);
          goto errout_with_buffer;
        }
    }
#endif

  /* 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_lock;

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

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

#ifdef CONFIG_SMARTFS_USE_SECTOR_BUFFER
  kmm_free(sf->buffer);
#endif /* CONFIG_SMARTFS_USE_SECTOR_BUFFER */
  kmm_free(sf);

errout_with_lock:
  nxmutex_unlock(&g_lock);
  if (ret == -EINVAL)
    {
      ret = -EIO;
    }

  return ret;
}

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

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

  /* Sanity checks */

  DEBUGASSERT(filep->f_priv != 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 lock */

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return ret;
    }

  /* 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;
    }

#ifdef CONFIG_SMARTFS_USE_SECTOR_BUFFER
  if (sf->buffer)
    {
      kmm_free(sf->buffer);
    }
#endif

  kmm_free(sf);

okout:
  nxmutex_unlock(&g_lock);
  return OK;
}

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

static ssize_t smartfs_read(FAR struct file *filep, FAR char *buffer,
                            size_t buflen)
{
  FAR struct inode                  *inode;
  FAR struct smartfs_mountpt_s      *fs;
  FAR struct smartfs_ofile_s        *sf;
  struct smart_read_write_s          readwrite;
  FAR 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);

  /* 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 lock */

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return (ssize_t)ret;
    }

  /* 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 current sector into our buffer */

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

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

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

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

      bytesinsector = SMARTFS_USED(header);
      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 bytes to 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_lock:
  nxmutex_unlock(&g_lock);
  return ret;
}

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

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

  DEBUGASSERT(filep->f_priv != 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 lock */

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return (ssize_t)ret;
    }

  /* 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_lock;
    }

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

  if (sf->oflags & O_APPEND)
    {
      ret = smartfs_seek_internal(fs, sf, 0, SEEK_END);
      if (ret < 0)
        {
          ret = -EIO;
          goto errout_with_lock;
        }
    }

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

  header = (FAR 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 = (FAR 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)
            {
              ferr("ERROR: Error %d writing sector %d data\n",
                   ret, sf->currsector);
              goto errout_with_lock;
            }

          /* 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 = (FAR 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)
            {
              ferr("ERROR: Error %d reading sector %d header\n",
                   ret, sf->currsector);
              goto errout_with_lock;
            }

          /* 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.
       */

#ifdef CONFIG_SMARTFS_USE_SECTOR_BUFFER
      readwrite.count = fs->fs_llformat.availbytes - sf->curroffset;
      if (readwrite.count > buflen)
        {
          readwrite.count = buflen;
        }

      memcpy(&sf->buffer[sf->curroffset], &buffer[byteswritten],
             readwrite.count);
      sf->bflags |= SMARTFS_BFLAG_DIRTY;

#else  /* CONFIG_SMARTFS_USE_SECTOR_BUFFER */
      readwrite.offset = sf->curroffset;
      readwrite.logsector = sf->currsector;
      readwrite.buffer = (FAR 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)
            {
              ferr("ERROR: Error %d writing sector %d data\n",
                   ret, sf->currsector);
              goto errout_with_lock;
            }
        }

#endif /* CONFIG_SMARTFS_USE_SECTOR_BUFFER */

      /* 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 */

#ifdef CONFIG_SMARTFS_USE_SECTOR_BUFFER
      if (sf->curroffset == fs->fs_llformat.availbytes && buflen)
        {
          /* First get a new chained sector */

          ret = FS_IOCTL(fs, BIOC_ALLOCSECT, 0xffff);
          if (ret < 0)
            {
              ferr("ERROR: Error %d allocating new sector\n", ret);
              goto errout_with_lock;
            }

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

          header = (FAR struct smartfs_chain_header_s *)sf->buffer;
          SMARTFS_SET_NEXTSECTOR(header, ret);

          /* Now sync the file to write this sector out */

          ret = smartfs_sync_internal(fs, sf);
          if (ret != OK)
            {
              goto errout_with_lock;
            }

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

          if (sf->currsector == SMARTFS_NEXTSECTOR(header))
            {
              /* Error allocating logical sector! */

              ferr("ERROR: Duplicate logical sector %d\n", sf->currsector);
            }

          sf->bflags = SMARTFS_BFLAG_DIRTY;
          sf->currsector = SMARTFS_NEXTSECTOR(header);
          sf->curroffset = sizeof(struct smartfs_chain_header_s);
          memset(sf->buffer, CONFIG_SMARTFS_ERASEDSTATE,
                 fs->fs_llformat.availbytes);
          header->type = SMARTFS_DIRENT_TYPE_FILE;
        }
#else  /* CONFIG_SMARTFS_USE_SECTOR_BUFFER */

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

          ret = smartfs_sync_internal(fs, sf);
          if (ret != OK)
            {
              goto errout_with_lock;
            }

          /* Allocate a new sector if needed */

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

              ret = FS_IOCTL(fs, BIOC_ALLOCSECT, 0xffff);
              if (ret < 0)
                {
                  ferr("ERROR: Error %d allocating new sector\n", ret);
                  goto errout_with_lock;
                }

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

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

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

              if (sf->currsector == SMARTFS_NEXTSECTOR(header))
                {
                  /* Error allocating logical sector! */

                  ferr("ERROR: Duplicate logical sector %d\n",
                        sf->currsector);
                }

              sf->currsector = SMARTFS_NEXTSECTOR(header);
              sf->curroffset = sizeof(struct smartfs_chain_header_s);
            }
        }
#endif /* CONFIG_SMARTFS_USE_SECTOR_BUFFER */
    }

  ret = byteswritten;

errout_with_lock:
  nxmutex_unlock(&g_lock);
  return ret;
}

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

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

  /* Sanity checks */

  DEBUGASSERT(filep->f_priv != 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 lock */

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return (off_t)ret;
    }

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

  ret = smartfs_seek_internal(fs, sf, offset, whence);
  if (ret >= 0)
    {
      filep->f_pos = ret;
    }

  nxmutex_unlock(&g_lock);
  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)
{
  FAR struct inode             *inode;
  FAR struct smartfs_mountpt_s *fs;
  FAR struct smartfs_ofile_s   *sf;
  int                           ret;

  /* Sanity checks */

  DEBUGASSERT(filep->f_priv != 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 lock */

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return ret;
    }

  ret = smartfs_sync_internal(fs, sf);

  nxmutex_unlock(&g_lock);
  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)
{
  FAR struct smartfs_ofile_s *sf;

  finfo("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 = sf;

  return OK;
}

/****************************************************************************
 * Name: smartfs_fstat
 *
 * Description:
 *   Obtain information about an open file associated with the file
 *   descriptor 'fd', and will write it to the area pointed to by 'buf'.
 *
 ****************************************************************************/

static int smartfs_fstat(FAR const struct file *filep, FAR struct stat *buf)
{
  FAR struct inode *inode;
  FAR struct smartfs_mountpt_s *fs;
  FAR struct smartfs_ofile_s *sf;
  int ret;

  DEBUGASSERT(buf != NULL);

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

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

  fs    = inode->i_private;
  DEBUGASSERT(fs != NULL);

  /* Take the lock */

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return ret;
    }

  /* Return information about the directory entry in the stat structure */

  smartfs_stat_common(fs, &sf->entry, buf);
  nxmutex_unlock(&g_lock);
  return OK;
}

/****************************************************************************
 * Name: smartfs_truncate
 *
 * Description:
 *   Set the length of the open, regular file associated with the file
 *   structure 'filep' to 'length'.
 *
 ****************************************************************************/

static int smartfs_truncate(FAR struct file *filep, off_t length)
{
  FAR struct inode *inode;
  FAR struct smartfs_mountpt_s *fs;
  FAR struct smartfs_ofile_s *sf;
  off_t oldsize;
  int ret;

  DEBUGASSERT(filep->f_priv != 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 lock */

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return ret;
    }

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

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

  /* Are we shrinking the file?  Or extending it? */

  oldsize = sf->entry.datlen;
  if (oldsize == length)
    {
      /* Let's not and say we did */

      ret = OK;
    }
  else if (oldsize > length)
    {
      /* We are shrinking the file */

      ret = smartfs_shrinkfile(fs, sf, length);
    }
  else
    {
      /* Otherwise we are extending the file.  This is essentially the same
       * as a write except that (1) we write zeros and (2) we don't update
       * the file position.
       */

      ret = smartfs_extendfile(fs, sf, length);
    }

errout_with_lock:

  /* Relinquish exclusive access */

  nxmutex_unlock(&g_lock);
  return ret;
}

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

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

  /* Sanity checks */

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

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

  fs = mountpt->i_private;
  sdir = kmm_zalloc(sizeof(*sdir));
  if (sdir == NULL)
    {
      return -ENOMEM;
    }

  /* Take the lock */

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      goto errout_with_sdir;
    }

  /* Search for the path on the volume */

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

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

  sdir->fs_firstsector = entry.firstsector;
  sdir->fs_currsector = entry.firstsector;
  sdir->fs_curroffset = sizeof(struct smartfs_chain_header_s);

  *dir = &sdir->fs_base;
  nxmutex_unlock(&g_lock);
  return OK;

errout_with_lock:

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

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

  nxmutex_unlock(&g_lock);

errout_with_sdir:
  kmm_free(sdir);
  return ret;
}

/****************************************************************************
 * Name: smartfs_closedir
 *
 * Description: Close directory
 *
 ****************************************************************************/

static int smartfs_closedir(FAR struct inode *mountpt,
                            FAR struct fs_dirent_s *dir)
{
  DEBUGASSERT(dir);
  kmm_free(dir);
  return 0;
}

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

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

  /* Sanity checks */

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

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

  fs = mountpt->i_private;
  sdir = (FAR struct smartfs_dir_s *)dir;

  /* Take the lock */

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return ret;
    }

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

  entrysize = sizeof(struct smartfs_entry_header_s) +
    fs->fs_llformat.namesize;

  while (sdir->fs_currsector != SMARTFS_ERASEDSTATE_16BIT)
    {
      /* Read the logical sector */

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

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

      /* Note: directories don't use the header's used field
       *       so we search all possilble directory entries.
       */

      while (sdir->fs_curroffset + entrysize < ret)
        {
          /* Point to next entry */

          entry = (FAR struct smartfs_entry_header_s *)&fs->fs_rwbuffer[
            sdir->fs_curroffset];

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

#ifdef CONFIG_SMARTFS_ALIGNED_ACCESS
          if (((smartfs_rdle16(&entry->flags)
                & SMARTFS_DIRENT_EMPTY) ==
              (SMARTFS_ERASEDSTATE_16BIT & SMARTFS_DIRENT_EMPTY)) ||
              ((smartfs_rdle16(&entry->flags)
                & SMARTFS_DIRENT_ACTIVE) !=
              (SMARTFS_ERASEDSTATE_16BIT & SMARTFS_DIRENT_ACTIVE)))
#else
          if (((entry->flags & SMARTFS_DIRENT_EMPTY) ==
              (SMARTFS_ERASEDSTATE_16BIT & SMARTFS_DIRENT_EMPTY)) ||
              ((entry->flags & SMARTFS_DIRENT_ACTIVE) !=
              (SMARTFS_ERASEDSTATE_16BIT & SMARTFS_DIRENT_ACTIVE)))
#endif
            {
              /* This entry isn't valid, skip it */

              sdir->fs_curroffset += entrysize;
              continue;
            }

          /* Entry found!  Report it */

#ifdef CONFIG_SMARTFS_ALIGNED_ACCESS
          if ((smartfs_rdle16(&entry->flags) & SMARTFS_DIRENT_TYPE) ==
              SMARTFS_DIRENT_TYPE_DIR)
#else
          if ((entry->flags & SMARTFS_DIRENT_TYPE) ==
              SMARTFS_DIRENT_TYPE_DIR)
#endif
            {
              dentry->d_type = DTYPE_DIRECTORY;
            }
          else
            {
              dentry->d_type = DTYPE_FILE;
            }

          /* Copy the entry name to dirent */

          strlcpy(dentry->d_name, entry->name, sizeof(dentry->d_name));

          /* Now advance to the next entry */

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

              sdir->fs_curroffset =
                sizeof(struct smartfs_chain_header_s);
              header = (FAR struct smartfs_chain_header_s *)fs->fs_rwbuffer;
              sdir->fs_currsector = SMARTFS_NEXTSECTOR(header);
            }

          /* Now exit */

          ret = OK;
          goto errout_with_lock;
        }

      /* 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 = (FAR struct smartfs_chain_header_s *)fs->fs_rwbuffer;
      sdir->fs_curroffset = sizeof(struct smartfs_chain_header_s);
      sdir->fs_currsector = SMARTFS_NEXTSECTOR(header);
    }

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

  ret = -ENOENT;

errout_with_lock:
  nxmutex_unlock(&g_lock);
  return ret;
}

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

static int smartfs_rewinddir(FAR struct inode *mountpt,
                             FAR struct fs_dirent_s *dir)
{
  FAR struct smartfs_dir_s *sdir = (FAR struct smartfs_dir_s *)dir;

  /* Sanity checks */

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

  /* Reset the directory to the first entry */

  sdir->fs_currsector = sdir->fs_firstsector;
  sdir->fs_curroffset = sizeof(struct smartfs_chain_header_s);

  return 0;
}

/****************************************************************************
 * 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, FAR const void *data,
                        FAR void **handle)
{
  FAR 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 = (FAR struct smartfs_mountpt_s *)
    kmm_zalloc(sizeof(struct smartfs_mountpt_s));
  if (!fs)
    {
      return -ENOMEM;
    }

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      kmm_free(fs);
      return ret;
    }

  /* 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)
    {
      nxmutex_unlock(&g_lock);
      kmm_free(fs);
      return ret;
    }

  *handle = fs;
  nxmutex_unlock(&g_lock);
  return OK;
}

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

static int smartfs_unbind(FAR void *handle, FAR struct inode **blkdriver,
                          unsigned int flags)
{
  FAR struct smartfs_mountpt_s *fs = (FAR 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 */

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return ret;
    }

  if (fs->fs_head != NULL)
    {
      /* We cannot unmount now.. there are open files */

      nxmutex_unlock(&g_lock);

      /* This implementation currently only supports unmounting if there are
       * no open file references.
       */

      return (flags != 0) ? -ENOSYS : -EBUSY;
    }
  else
    {
      /* Unmount ... close the block driver */

      ret = smartfs_unmount(fs);
    }

  nxmutex_unlock(&g_lock);
  kmm_free(fs);
  return ret;
}

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

static int smartfs_statfs(FAR struct inode *mountpt, FAR struct statfs *buf)
{
  FAR 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;

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return ret;
    }

  /* Implement the logic!! */

  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;
  if (buf->f_blocks == 65535)
    {
      buf->f_blocks++;
    }

  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;

  nxmutex_unlock(&g_lock);
  return ret;
}

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

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

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return ret;
    }

  /* 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_lock;
        }

      /* 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_lock;
    }

  ret = OK;

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

  nxmutex_unlock(&g_lock);
  return ret;
}

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

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

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

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

  fs = mountpt->i_private;

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return ret;
    }

  /* 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_lock;
    }
  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-existent dir segment) */

          goto errout_with_lock;
        }

      /* Check mode */

      /* Create the directory */

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

      ret = OK;
    }

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

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

  nxmutex_unlock(&g_lock);
  return ret;
}

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

int smartfs_rmdir(FAR struct inode *mountpt, FAR const char *relpath)
{
  FAR struct smartfs_mountpt_s *fs;
  int                           ret;
  struct smartfs_entry_s        entry;
  FAR 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 lock */

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return ret;
    }

  /* 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_lock;
        }

      /* TODO:  Need to check permissions?  */

      /* Check if the directory is empty */

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

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

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

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

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

      goto errout_with_lock;
    }

  ret = OK;

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

  nxmutex_unlock(&g_lock);
  return ret;
}

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

int smartfs_rename(FAR struct inode *mountpt, FAR const char *oldrelpath,
                   FAR const char *newrelpath)
{
  FAR struct smartfs_mountpt_s      *fs;
  int                                ret;
  struct smartfs_entry_s             oldentry;
  uint16_t                           oldparentdirsector;
  FAR const char                    *oldfilename;
  struct smartfs_entry_s             newentry;
  uint16_t                           newparentdirsector;
  FAR const char                    *newfilename;
  mode_t                             mode;
  uint16_t                           type;
  FAR 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;

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return ret;
    }

  /* 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_lock;
    }

  /* Search for the new entry and validate it DOESN'T exist. */

  ret = smartfs_finddirentry(fs, &newentry, newrelpath, &newparentdirsector,
                             &newfilename);
  if (ret == OK)
    {
      /* It is an error if the directory entry at newrelpath already
       * exists.  The necessary steps to avoid this case should have been
       * handled by higher level logic in the VFS.
       */

      ret = -EEXIST;
      goto errout_with_lock;
    }

  /* 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,
                                NULL);
      if (ret != OK)
        {
          goto errout_with_lock;
        }

      /* Now mark the old entry as inactive */

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

      direntry = (FAR 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 = (FAR uint8_t *)&direntry->flags;
      ret = FS_IOCTL(fs, BIOC_WRITESECT, (unsigned long)&readwrite);
      if (ret < 0)
        {
          ferr("ERROR: Error %d writing flag bytes for sector %d\n",
               ret, readwrite.logsector);
          goto errout_with_lock;
        }
    }
  else
    {
      /* Trying to create in a directory that doesn't exist */

      ret = -ENOENT;
      goto errout_with_lock;
    }

  ret = OK;

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

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

  nxmutex_unlock(&g_lock);
  return ret;
}

/****************************************************************************
 * Name: smartfs_stat_common
 *
 * Description:
 *   Return information about a directory entry
 *
 ****************************************************************************/

static void smartfs_stat_common(FAR struct smartfs_mountpt_s *fs,
                                FAR struct smartfs_entry_s *entry,
                                FAR struct stat *buf)
{
  /* 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;
    }
  else
    {
      /* Mask out the file type */

      buf->st_mode = entry->flags & ~S_IFMT;

      /* Add the file type based on the SmartFS entry flags */

      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;
    }
}

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

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

  /* Sanity checks */

  DEBUGASSERT(mountpt && mountpt->i_private);

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

  fs = mountpt->i_private;

  ret = nxmutex_lock(&g_lock);
  if (ret < 0)
    {
      return ret;
    }

  /* Find the directory entry corresponding to relpath */

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

  /* Return information about the directory entry in the stat structure */

  smartfs_stat_common(fs, &entry, buf);
  ret = OK;

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

  nxmutex_unlock(&g_lock);
  return ret;
}

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