Fix a FAT mount bug

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1249 42af7a65-404d-4744-a932-0658087f49c3

3 files changed, 30 insertions, 22 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index 04d47cfc1..ad48012d8 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -548,10 +548,12 @@
 	  no longer have to be the same.
 	* Add a loop device that converts a file into a block device.
 	* Each NSH command can not be disabled through a configuration setting. All of these
-          settings make the configuration of NSH potentially complex but also allow it to squeeze
-          into very small memory footprints.
+	 settings make the configuration of NSH potentially complex but also allow it to squeeze
+	  into very small memory footprints.
 	* Added a block to character (BCH) driver.  This is kind of the reverse of the loop
 	  device; it allows you access a block device like a character device.
 	* Added strcasecmp() and strncasecmp()
 	* NSH: Added the 'dd' command
 	* NSH: Added the 'losetup' command
+	* Fixed a FAT bug:  After recent changes, it would mount a (invalid) FAT file system
+	  even if the medium is not formatted!
diff --git a/nuttx/Documentation/NuttX.html b/nuttx/Documentation/NuttX.html
index 6bb9c58c3..a1bd82f02 100644
--- a/nuttx/Documentation/NuttX.html
+++ b/nuttx/Documentation/NuttX.html
@@ -1191,12 +1191,14 @@ nuttx-0.3.18 2008-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr>
 	  no longer have to be the same.
 	* Add a loop device that converts a file into a block device.
 	* Each NSH command can not be disabled through a configuration setting. All of these
-          settings make the configuration of NSH potentially complex but also allow it to squeeze
-          into very small memory footprints.
+	  settings make the configuration of NSH potentially complex but also allow it to squeeze
+	  into very small memory footprints.
 	* Added a block to character (BCH) driver.  This is kind of the reverse of the loop
 	  device; it allows you access a block device like a character device.
 	* NSH: Added the 'dd' command
 	* NSH: Added the 'losetup' command
+	* Fixed a FAT bug:  After recent changes, it would mount a (invalid) FAT file system
+	  even if the medium is not formatted!
 
 pascal-0.1.3 2008-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr>
 
diff --git a/nuttx/fs/fat/fs_fat32util.c b/nuttx/fs/fat/fs_fat32util.c
index 6c96746cc..dc1404f9e 100644
--- a/nuttx/fs/fat/fs_fat32util.c
+++ b/nuttx/fs/fat/fs_fat32util.c
@@ -314,10 +314,10 @@ static int fat_checkbootrecord(struct fat_mountpt_s *fs)
 
   fs->fs_rootentcnt = MBR_GETROOTENTCNT(fs->fs_buffer);
   if (fs->fs_rootentcnt != 0)
-  {
+    {
       notfat32       = TRUE; /* Must be zero for FAT32 */
       rootdirsectors = (32 * fs->fs_rootentcnt  + fs->fs_hwsectorsize - 1) / fs->fs_hwsectorsize;
-  }
+    }
 
   /* Determine the number of sectors in a FAT. */
 
@@ -655,28 +655,32 @@ int fat_mount(struct fat_mountpt_s *fs, boolean writeable)
        * partition and see if we can find the boot record there.
        */
  
-      if (PART1_GETTYPE(fs->fs_buffer) != 0)
+      if (PART1_GETTYPE(fs->fs_buffer) == 0)
         {
-          /* There appears to be a partition, get the sector number of the
-           * partition (LBA)
-           */
+          fdbg("No MBR or partition\n");
+          goto errout_with_buffer;
+        }
 
-          fs->fs_fatbase = PART1_GETSTARTSECTOR(fs->fs_buffer);
+      /* There appears to be a partition, get the sector number of the
+       * partition (LBA)
+       */
 
-          /* Read the new candidate boot sector */
+      fs->fs_fatbase = PART1_GETSTARTSECTOR(fs->fs_buffer);
 
-          ret = fat_hwread(fs, fs->fs_buffer, fs->fs_fatbase, 1);
-          if (ret < 0)
-          {
-              goto errout_with_buffer;
-          }
+      /* Read the new candidate boot sector */
+
+      ret = fat_hwread(fs, fs->fs_buffer, fs->fs_fatbase, 1);
+      if (ret < 0)
+        {
+          goto errout_with_buffer;
+        }
 
-          /* Check if this is a boot record */
+      /* Check if this is a boot record */
 
-          if (fat_checkbootrecord(fs) != OK)
-            {
-              goto errout_with_buffer;
-            }
+      if (fat_checkbootrecord(fs) != OK)
+        {
+          fdbg("No valid MBR\n");
+          goto errout_with_buffer;
         }
     }