Extend NXFFS tests; bugfixes

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3547 42af7a65-404d-4744-a932-0658087f49c3

7 files changed, 351 insertions, 72 deletions

diff --git a/nuttx/fs/nxffs/Make.defs b/nuttx/fs/nxffs/Make.defs
index 4d7dcf3f4..a73950c3f 100644
--- a/nuttx/fs/nxffs/Make.defs
+++ b/nuttx/fs/nxffs/Make.defs
@@ -36,9 +36,9 @@
 ifeq ($(CONFIG_FS_NXFFS),y)
 ASRCS +=
 CSRCS += nxffs_block.c nxffs_blockstats.c nxffs_cache.c nxffs_dirent.c \
-		 nxffs_initialize.c nxffs_inode.c nxffs_ioctl.c nxffs_open.c \
-		 nxffs_pack.c nxffs_read.c nxffs_reformat.c nxffs_stat.c \
-		 nxffs_unlink.c nxffs_util.c nxffs_write.c
+		 nxffs_dump.c nxffs_initialize.c nxffs_inode.c nxffs_ioctl.c \
+		 nxffs_open.c nxffs_pack.c nxffs_read.c nxffs_reformat.c \
+		 nxffs_stat.c nxffs_unlink.c nxffs_util.c nxffs_write.c
 
 # Argument for dependency checking
 
diff --git a/nuttx/fs/nxffs/README.txt b/nuttx/fs/nxffs/README.txt
index 156a3436a..47a7d7f97 100755
--- a/nuttx/fs/nxffs/README.txt
+++ b/nuttx/fs/nxffs/README.txt
@@ -10,6 +10,8 @@ Contents:
   General operation

   Headers

   NXFFS Limitations

+  Multiple Writers

+  Things to Do

 

 General NXFFS organization

 ==========================

@@ -111,3 +113,41 @@ that you should be aware before opting to use NXFFS:
    an MTD driver (instead of a block driver) and bypass all of the normal

    mount operations.

 

+Multiple Writers

+================

+

+As mentioned in the limitations above, there can be only one file opened

+for writing at a time.  If one thread has a file opened for writing and

+another thread attempts to open a file for writing, then that second

+thread will be blocked and will have to wait for the first thread to

+close the file.

+

+Such behavior may or may not be a problem for your application, depending

+(1) how long the first thread keeps the file open for writing and (2) how

+critical the behavior of the second thread is.  Note that writing to FLASH

+can always trigger a major FLASH reorganization and, hence, there is no

+way to guarantee the first condition: The first thread may have the file

+open for a long time even if it only intends to write a small amount.

+

+Also note that a deadlock condition would occur if the SAME thread

+attempted to open two files for writing.  The thread would would be

+blocked waiting for itself to close the first file.

+

+Things to Do

+============

+

+- The implementation is not yet finished.  It needs at, a minimum,

+  completion of the file system packing logic.  It is not usuable without

+  that feature.

+- The statfs() implementation is minimal.  It whould have some calcuation

+  of the f_bfree, f_bavail, f_files, f_ffree return values.

+- There are too many allocs and frees.  More structures may need to be

+  pre-allocated.

+- The file name is always extracted and held in allocated, variable-length

+  memory.  The file name is not used during reading and eliminating the

+  file name in the entry structure would improve performance.

+- There is a big inefficient in reading.  On each read, the logic searches

+  for the read position from the beginning of the file each time.  This

+  may be necessary whenever an lseek() is done, but not in general.  Read

+  performance could be improved by keeping FLASH offset and read positional

+  information in the read open file structure.

diff --git a/nuttx/fs/nxffs/nxffs.h b/nuttx/fs/nxffs/nxffs.h
index 9ed65cf67..912e0db92 100644
--- a/nuttx/fs/nxffs/nxffs.h
+++ b/nuttx/fs/nxffs/nxffs.h
@@ -259,21 +259,7 @@ struct nxffs_wrfile_s
 
   struct nxffs_ofile_s      ofile;
 
-  /* The following fields are required to support the current write
-   * operation.
-   *
-   * 1. Inode header location determined (but not yet written).
-   * 2. Block header location determined (but not yet written).
-   * 3. Check FLASH memory to make sure that it is erased.
-   * 4. As data is written, datlen is updated and the data is written to FLASH.
-   * 5. If the end of the FLASH block is encountered, the data block CRC is
-   *    calculated and the block header is also written to flash.
-   * 6. When the file is closed, the final, partial data block is written to
-   *    FLASH in the same way. Any previously identified file with the same
-   *    name is deleted.  The final file size is determined, the header
-   *    CRC is calculated, and the inode header is written to FLASH, completing
-   *    the write operation.
-   */
+  /* The following fields are required to support the write operation */
 
   bool                      truncate;   /* Delete a file of the same name */
   uint16_t                  datlen;     /* Number of bytes written in data block */
@@ -287,8 +273,8 @@ struct nxffs_volume_s
 {
   FAR struct mtd_dev_s     *mtd;       /* Supports FLASH access */
   sem_t                     exclsem;   /* Used to assure thread-safe access */
+  sem_t                     wrsem;     /* Enforces single writer restriction */
   struct mtd_geometry_s     geo;       /* Device geometry */
-  uint8_t                   wrbusy: 1; /* 1: Volume open for writing */
   uint8_t                   blkper;    /* R/W blocks per erase block */
   uint8_t                   ncached;   /* Number of blocks in cache */
   uint16_t                  iooffset;  /* Next offset in read/write access (in ioblock) */
diff --git a/nuttx/fs/nxffs/nxffs_dump.c b/nuttx/fs/nxffs/nxffs_dump.c
new file mode 100644
index 000000000..e93200afd
--- /dev/null
+++ b/nuttx/fs/nxffs/nxffs_dump.c
@@ -0,0 +1,183 @@
+/****************************************************************************
+ * fs/nxffs/nxffs_dump.c
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * References: Linux/Documentation/filesystems/romfs.txt
+ *
+ * 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 <string.h>
+#include <debug.h>
+#include <errno.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/ioctl.h>
+#include <nuttx/mtd.h>
+
+#include "nxffs.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: nxffs_analyze
+ *
+ * Description:
+ *   Analyze the content of one block.
+ *
+ ****************************************************************************/
+
+#if defined(CONFIG_DEBUG) && defined(CONFIG_DEBUG_FS)
+static inline void nxffs_analyze(FAR uint8_t *buffer, size_t buflen, off_t blockno)
+{
+  FAR struct nxffs_block_s *blkhdr;
+
+  /* Verify that there is a header on the block */
+
+  blkhdr = (FAR struct nxffs_block_s *)buffer;
+  if (memcmp(blkhdr->magic, g_blockmagic, NXFFS_MAGICSIZE) != 0)
+    {
+      fdbg("Block %d: ERROR -- no header\n", blockno);
+    }
+  else if (blkhdr->state == BLOCK_STATE_GOOD)
+    {
+      fdbg("Block %d: GOOD\n", blockno);
+    }
+  else if (blkhdr->state == BLOCK_STATE_BAD)
+    {
+      fdbg("Block %d: BAD\n", blockno);
+    }
+  else
+    {
+      fdbg("Block %d: ERROR -- bad state\n", blockno);
+    }
+}
+#endif
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: nxffs_dump
+ *
+ * Description:
+ *   Dump a summary of the contents of an NXFFS file system.  CONFIG_DEBUG
+ *   and CONFIG_DEBUG_FS must be enabled for this function to do anything.
+ *
+ * Input Parameters:
+ *   mtd - The MTD device that provides the interface to NXFFS-formatted media.
+ *
+ * Returned Value:
+ *   Zero is returned on success.  Otherwise, a negated errno value is
+ *   returned to indicate the nature of the failure.
+ *
+ ****************************************************************************/
+
+int nxffs_dump(FAR struct mtd_dev_s *mtd)
+{
+#if defined(CONFIG_DEBUG) && defined(CONFIG_DEBUG_FS)
+  struct mtd_geometry_s geo;
+  FAR uint8_t *buffer;
+  off_t nblocks;
+  off_t block;
+  int ret;
+
+  /* Get the volume geometry. (casting to uintptr_t first eliminates
+   * complaints on some architectures where the sizeof long is different
+   * from the size of a pointer).
+   */
+
+  ret = MTD_IOCTL(mtd, MTDIOC_GEOMETRY, (unsigned long)((uintptr_t)&geo));
+  if (ret < 0)
+    {
+      fdbg("MTD ioctl(MTDIOC_GEOMETRY) failed: %d\n", -ret);
+      goto errout;
+    }
+
+  /* Allocate a buffer to hold one block */
+
+  buffer = (FAR uint8_t *)kmalloc(geo.blocksize);
+  if (!buffer)
+    {
+      fdbg("Failed to allocate block cache\n");
+      ret = -ENOMEM;
+      goto errout;
+    }
+
+  /* Now read every block on the device */
+
+  nblocks = geo.erasesize * geo.neraseblocks / geo.blocksize;
+  for (block = 0; block < nblocks; block++)
+    {
+      /* Read the next block */
+
+      ret = MTD_BREAD(mtd, block, 1, buffer);
+      if (ret < 0)
+        {
+          fdbg("Failed to read block %d\n", block);
+          goto errout_with_block;
+        }
+
+      /* Analyze the block */
+
+      nxffs_analyze(buffer, geo.blocksize, block);
+    }
+
+errout_with_block:
+  kfree(buffer);
+errout:
+  return ret;
+
+#else
+  return -ENOSYS;
+#endif
+}
diff --git a/nuttx/fs/nxffs/nxffs_initialize.c b/nuttx/fs/nxffs/nxffs_initialize.c
index cd729a9f2..adf1f76f7 100644
--- a/nuttx/fs/nxffs/nxffs_initialize.c
+++ b/nuttx/fs/nxffs/nxffs_initialize.c
@@ -183,6 +183,7 @@ int nxffs_initialize(FAR struct mtd_dev_s *mtd)
 
   volume->mtd = mtd;
   sem_init(&volume->exclsem, 0, 1);
+  sem_init(&volume->wrsem, 0, 1);
 
   /* Get the volume geometry. (casting to uintptr_t first eliminates
    * complaints on some architectures where the sizeof long is different
diff --git a/nuttx/fs/nxffs/nxffs_open.c b/nuttx/fs/nxffs/nxffs_open.c
index 09a82f6e9..f2b5c3e04 100644
--- a/nuttx/fs/nxffs/nxffs_open.c
+++ b/nuttx/fs/nxffs/nxffs_open.c
@@ -340,13 +340,27 @@ static inline int nxffs_wropen(FAR struct nxffs_volume_s *volume,
    * in FLASH, only a single file may be extending the FLASH region.
    */
 
-  if (volume->wrbusy)
+  ret = sem_wait(&volume->wrsem);
+  if (ret != OK)
     {
-      fdbg("There is already a file writer\n");
-      ret = -ENOSYS;
+      fdbg("sem_wait failed: %d\n", ret);
+      ret = -errno;
       goto errout;
     }
 
+  /* Get exclusive access to the volume.  Note that the volume exclsem
+   * protects the open file list.  Note that exclsem is ALWAYS taken
+   * after wrsem to avoid deadlocks.
+   */
+
+  ret = sem_wait(&volume->exclsem);
+  if (ret != OK)
+    {
+      fdbg("sem_wait failed: %d\n", ret);
+      ret = -errno;
+      goto errout_with_wrsem;
+    }
+
   /* Check if the file exists */
 
   ret = nxffs_findinode(volume, name, &entry);
@@ -360,7 +374,7 @@ static inline int nxffs_wropen(FAR struct nxffs_volume_s *volume,
         {
           fdbg("File exists, can't create O_EXCL\n");
           ret = -EEXIST;
-          goto errout;
+          goto errout_with_exclsem;
         }
 
       /* Were we asked to truncate the file?  NOTE: Don't truncate the
@@ -386,7 +400,7 @@ static inline int nxffs_wropen(FAR struct nxffs_volume_s *volume,
         {
           fdbg("File %s exists and we were not asked to truncate it\n");
           ret = -ENOSYS;
-          goto errout;
+          goto errout_with_exclsem;
         }
     }
 
@@ -398,7 +412,7 @@ static inline int nxffs_wropen(FAR struct nxffs_volume_s *volume,
     {
       fdbg("Not asked to create the file\n");
       ret = -ENOENT;
-      goto errout;
+      goto errout_with_exclsem;
     }
 
   /* Make sure that the length of the file name will fit in a uint8_t */
@@ -408,7 +422,7 @@ static inline int nxffs_wropen(FAR struct nxffs_volume_s *volume,
     {
       fdbg("Name is too long: %d\n", namlen);
       ret = -EINVAL;
-      goto errout;
+      goto errout_with_exclsem;
     }
 
   /* Yes.. Create a new structure that will describe the state of this open
@@ -424,7 +438,7 @@ static inline int nxffs_wropen(FAR struct nxffs_volume_s *volume,
   if (!wrfile)
     {
       ret = -ENOMEM;
-      goto errout;
+      goto errout_with_exclsem;
     }
 #endif
 
@@ -563,11 +577,13 @@ static inline int nxffs_wropen(FAR struct nxffs_volume_s *volume,
   volume->ofiles      = &wrfile->ofile;
 
   /* Indicate that the volume is open for writing and return the open file
-   * instance.
+   * instance.  Releasing exclsem allows other readers while the write is
+   * in progress.  But wrsem is still held for this open file, preventing
+   * any further writers until this inode is closed.s
    */
 
-  volume->wrbusy = 1;
   *ppofile = &wrfile->ofile;
+  sem_post(&volume->exclsem);
   return OK;
 
 errout_with_name:
@@ -576,6 +592,11 @@ errout_with_ofile:
 #ifndef CONFIG_NXFSS_PREALLOCATED
   kfree(wrfile);
 #endif
+
+errout_with_exclsem:
+  sem_post(&volume->exclsem);
+errout_with_wrsem:
+  sem_post(&volume->wrsem);
 errout:
   return ret;
 }
@@ -595,6 +616,18 @@ static inline int nxffs_rdopen(FAR struct nxffs_volume_s *volume,
   FAR struct nxffs_ofile_s *ofile;
   int ret;
 
+  /* Get exclusive access to the volume.  Note that the volume exclsem
+   * protects the open file list.
+   */
+
+  ret = sem_wait(&volume->exclsem);
+  if (ret != OK)
+    {
+      fdbg("sem_wait failed: %d\n", ret);
+      ret = -errno;
+      goto errout;
+    }
+
   /* Check if the file has already been opened (for reading) */
 
   ofile = nxffs_findofile(volume, name);
@@ -607,7 +640,8 @@ static inline int nxffs_rdopen(FAR struct nxffs_volume_s *volume,
       if ((ofile->mode & O_WROK) != 0)
         {
           fdbg("File is open for writing\n");
-          return -ENOSYS;
+          ret = -ENOSYS;
+          goto errout_with_exclsem;
         }
 
       /* Just increment the reference count on the ofile */
@@ -629,7 +663,8 @@ static inline int nxffs_rdopen(FAR struct nxffs_volume_s *volume,
       if (!ofile)
         {
           fdbg("ofile allocation failed\n");
-          return -ENOMEM;
+          ret = -ENOMEM;
+          goto errout_with_exclsem;
         }
 
       /* Initialize the open file state structure */
@@ -643,8 +678,7 @@ static inline int nxffs_rdopen(FAR struct nxffs_volume_s *volume,
       if (ret != OK)
         {
           fdbg("Inode '%s' not found: %d\n", name, -ret);
-          kfree(ofile);
-          return ret;
+          goto errout_with_ofile;
         }
 
       /* Add the open file structure to the head of the list of open files */
@@ -656,7 +690,15 @@ static inline int nxffs_rdopen(FAR struct nxffs_volume_s *volume,
   /* Return the open file state structure */
 
   *ppofile = ofile;
+  sem_post(&volume->exclsem);
   return OK;
+
+errout_with_ofile:
+  kfree(ofile);
+errout_with_exclsem:
+  sem_post(&volume->exclsem);
+errout:
+  return ret;
 }
 
 /****************************************************************************
@@ -851,7 +893,7 @@ static int nxffs_wrclose(FAR struct nxffs_volume_s *volume,
   /* The volume is now available for other writers */
 
 errout:
-  volume->wrbusy = 0;
+  sem_post(&volume->wrsem);
   return ret;
 }
 
@@ -926,18 +968,6 @@ int nxffs_open(FAR struct file *filep, FAR const char *relpath,
   volume = (FAR struct nxffs_volume_s*)filep->f_inode->i_private;
   DEBUGASSERT(volume != NULL);
 
-  /* Get exclusive access to the volume.  Note that the volume exclsem
-   * protects the open file list.
-   */
-
-  ret = sem_wait(&volume->exclsem);
-  if (ret != OK)
-    {
-      ret = -errno;
-      fdbg("sem_wait failed: %d\n", ret);
-      goto errout;
-    }
-
 #ifdef CONFIG_FILE_MODE
 #  warning "Missing check for privileges based on inode->i_mode"
 #endif
@@ -949,13 +979,12 @@ int nxffs_open(FAR struct file *filep, FAR const char *relpath,
    * extension is supported.
    */
 
-   switch (mode & (O_WROK|O_RDOK))
+   switch (oflags & (O_WROK|O_RDOK))
      {
        case 0:
        default:
          fdbg("One of O_WRONLY/O_RDONLY must be provided\n");
-         ret = -EINVAL;
-         goto errout_with_semaphore;
+         return -EINVAL;
 
        case O_WROK:
          ret = nxffs_wropen(volume, relpath, mode, &ofile);
@@ -967,18 +996,15 @@ int nxffs_open(FAR struct file *filep, FAR const char *relpath,
 
        case O_WROK|O_RDOK:
          fdbg("O_RDWR is not supported\n");
-         ret = -ENOSYS;
-         goto errout_with_semaphore;
+         return -ENOSYS;
      }
 
-  /* Save open-specific state in filep->f_priv */
+  /* Save the reference to the open-specific state in filep->f_priv */
 
-  filep->f_priv = ofile;
-  ret = OK;
-
-errout_with_semaphore:
-  sem_post(&volume->exclsem);
-errout:
+  if (ret == OK)
+    {
+      filep->f_priv = ofile;
+    }
   return ret;
 }
 
diff --git a/nuttx/fs/nxffs/nxffs_read.c b/nuttx/fs/nxffs/nxffs_read.c
index 3648c1314..38b09acb1 100644
--- a/nuttx/fs/nxffs/nxffs_read.c
+++ b/nuttx/fs/nxffs/nxffs_read.c
@@ -61,6 +61,12 @@
  * Public Types
  ****************************************************************************/
 
+struct nxffs_blkentry_s
+{
+  off_t     hoffset;  /* Offset to the block data header */
+  uint16_t  datlen;   /* Length of data following the header */
+};
+
 /****************************************************************************
  * Public Variables
  ****************************************************************************/
@@ -88,7 +94,7 @@
  ****************************************************************************/
 
 static int nxffs_rdblkhdr(FAR struct nxffs_volume_s *volume, off_t offset,
-                          FAR size_t *datlen)
+                          FAR uint16_t *datlen)
 {
   struct nxffs_data_s blkhdr;
   uint32_t ecrc;
@@ -154,7 +160,7 @@ static int nxffs_rdblkhdr(FAR struct nxffs_volume_s *volume, off_t offset,
  ****************************************************************************/
 
 int nxffs_nextblock(FAR struct nxffs_volume_s *volume, off_t offset,
-                    FAR size_t *datlen)
+                    FAR struct nxffs_blkentry_s *blkentry)
 {
   int nmagic;
   int ch;
@@ -165,6 +171,13 @@ int nxffs_nextblock(FAR struct nxffs_volume_s *volume, off_t offset,
 
   nxffs_ioseek(volume, offset);
 
+  /* Skip the block header */
+
+  if (volume->iooffset < SIZEOF_NXFFS_BLOCK_HDR)
+    {
+      volume->iooffset = SIZEOF_NXFFS_BLOCK_HDR;
+    }
+
   /* Then begin searching */
   
   nerased = 0;
@@ -222,7 +235,15 @@ int nxffs_nextblock(FAR struct nxffs_volume_s *volume, off_t offset,
 
           else 
             {
-              ret = nxffs_rdblkhdr(volume, offset, datlen);
+              /* The offset to the header must be 4 bytes before the current
+               * FLASH seek location.
+               */
+
+              blkentry->hoffset = nxffs_iotell(volume) - 4;
+
+              /* Read the block header and verify the block at that address */
+
+              ret = nxffs_rdblkhdr(volume, blkentry->hoffset, &blkentry->datlen);
               if (ret == OK)
                 {
                   fdbg("Found a valid fileheader\n");
@@ -261,31 +282,42 @@ static ssize_t nxffs_rdseek(FAR struct nxffs_volume_s *volume,
                             FAR struct nxffs_entry_s *entry,
                             off_t fpos)
 {
-  size_t datlen = 0;
-  size_t blklen = 0;
+  struct nxffs_blkentry_s blkentry;
+  size_t datstart;
+  size_t datend;
   off_t offset = fpos;
   int ret;
 
   /* Loop until we read the data block containing the desired position */
 
+  datend = 0;
   do
     {
-      /* Get the data offset at the start of the next data block */
+      /* Find the next the next data block */
 
-      datlen += blklen;
-
-      /* Get the length of the next data block */
-
-      ret = nxffs_nextblock(volume, offset, &blklen);
+      ret = nxffs_nextblock(volume, offset, &blkentry);
       if (ret < 0)
         {
           fdbg("nxffs_nextblock failed: %d\n", -ret);
           return ret;
         }
+ 
+      /* Get the range of data offses for this data block */
+
+      datstart  = datend;
+      datend   += blkentry.datlen;
+
+      /* Protect against reading past the end of the file */
+
+       /* Offset to search for the the next data block */
+
+       offset += blkentry.hoffset + SIZEOF_NXFFS_DATA_HDR + blkentry.datlen;
     }
-  while (datlen <= fpos && datlen + blklen > fpos);
+  while (datend <= fpos);
+
+  /* Return the offset to the data within the current data block */
 
-  volume->iooffset += (fpos - datlen);
+  nxffs_ioseek(volume, blkentry.hoffset + SIZEOF_NXFFS_DATA_HDR + fpos - datstart);
   return OK;
 }
 
@@ -343,12 +375,23 @@ ssize_t nxffs_read(FAR struct file *filep, FAR char *buffer, size_t buflen)
       goto errout_with_semaphore;
     }
 
+  /* Don't seek past the end of the file */
+
+  if (filep->f_pos >= ofile->entry.datlen)
+    {
+      /* Return end-of-file */
+
+      filep->f_pos = ofile->entry.datlen;
+      ret = 0;
+      goto errout_with_semaphore;
+    }
+
   /* Seek to the current file offset */
 
   ret = nxffs_rdseek(volume, &ofile->entry, filep->f_pos);
   if (ret < 0)
     {
-      fdbg("nxffs_fwseek failed: %d\n", -ret);
+      fdbg("nxffs_rdseek failed: %d\n", -ret);
       ret = -EACCES;
       goto errout_with_semaphore;
     }