Fix a stray write into the FAT

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3958 42af7a65-404d-4744-a932-0658087f49c3

ChangeLog

@@ -2076,7 +2076,7 @@
 	* sched/clock_gettime.c:  Correct an error in the tv_nsec calculation
 	  that happens only config CONFIG_RTC is enabled.
 	* arch/arm/src/stm32/stm32_i2c.c:  Correct some bugs related to waiting
-	  to the I2C STOP condition to be cleared.
+	  for the I2C STOP condition to be cleared.
 
 6.10 2011-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr>
 
@@ -2089,3 +2089,7 @@
 	* fs/fat/fs_fat32.c: Fix a critical bug in the write logic:  It a tiny write
 	  cross a sector boundary, then two sector writes will occur.  The first part
 	  in the first sector may be written to the wrong sector number.
+	* fs/fat/fs_fat32util.c:  Fix a stray write into the FAT (always sector 964 on
+	  FAT32).  This bug will cause some lost chains.  I'm sure this bug could
+	  corrupt files but at present, the only thing I have seen is that before
+	  fixing this bug, the Windows chkdsk utility would report these lost chains.

fs/fat/fs_fat32.c

@@ -728,8 +728,8 @@ static ssize_t fat_write(FAR struct file *filep, const char *buffer,
               nsectors = ff->ff_sectorsincluster;
             }
 
-          /* We are not sure of the state of the file buffer so
+          /* We are not sure of the state of the sector cache so the
-           * the safest thing to do is write back any dirty, cached sector
+           * safest thing to do is write back any dirty, cached sector
            * and invalidate the current cache content.
            */
 

fs/fat/fs_fat32dirent.c

@@ -2505,7 +2505,7 @@ int fat_allocatedirentry(struct fat_mountpt_s *fs, struct fat_dirinfo_s *dirinfo
       for (i = fs->fs_fatsecperclus; i; i--)
         {
           ret = fat_hwwrite(fs, fs->fs_buffer, sector, 1);
-          if ( ret < 0)
+          if (ret < 0)
             {
               return ret;
             }

fs/fat/fs_fat32util.c

@@ -882,6 +882,7 @@ int fat_putcluster(struct fat_mountpt_s *fs, uint32_t clusterno, off_t nextclust
 
                   value = (uint8_t)nextcluster;
                 }
+
               fs->fs_buffer[fatindex] = value;
 
               /* With FAT12, the second byte of the cluster number may lie in
@@ -904,6 +905,7 @@ int fat_putcluster(struct fat_mountpt_s *fs, uint32_t clusterno, off_t nextclust
                   if (fat_fscacheread(fs, fatsector) < 0)
                     {
                       /* Read error */
+
                       break;
                     }
                 }
@@ -924,6 +926,7 @@ int fat_putcluster(struct fat_mountpt_s *fs, uint32_t clusterno, off_t nextclust
 
                   value = (fs->fs_buffer[fatindex] & 0xf0) | ((nextcluster >> 8) & 0x0f);
                 }
+
               fs->fs_buffer[fatindex] = value;
             }
           break;
@@ -937,6 +940,7 @@ int fat_putcluster(struct fat_mountpt_s *fs, uint32_t clusterno, off_t nextclust
               if (fat_fscacheread(fs, fatsector) < 0)
                 {
                   /* Read error */
+
                   break;
                 }
               FAT_PUTFAT16(fs->fs_buffer, fatindex, nextcluster & 0xffff);
@@ -952,6 +956,7 @@ int fat_putcluster(struct fat_mountpt_s *fs, uint32_t clusterno, off_t nextclust
               if (fat_fscacheread(fs, fatsector) < 0)
                 {
                   /* Read error */
+
                   break;
                 }
               FAT_PUTFAT32(fs->fs_buffer, fatindex, nextcluster & 0x0fffffff);
@@ -964,7 +969,7 @@ int fat_putcluster(struct fat_mountpt_s *fs, uint32_t clusterno, off_t nextclust
 
       /* Mark the modified sector as "dirty" and return success */
 
-      fs->fs_dirty = 1;
+      fs->fs_dirty = true;
       return OK;
     }
 
@@ -1067,8 +1072,8 @@ int32_t fat_extendchain(struct fat_mountpt_s *fs, uint32_t cluster)
         }
       else if (startsector < 2)
         {
-
           /* Oops.. this cluster does not exist. */
+
           return 0;
         }
       else if (startsector < fs->fs_nclusters)
@@ -1351,37 +1356,38 @@ int fat_fscacheflush(struct fat_mountpt_s *fs)
    */
 
   if (fs->fs_dirty)
-  {
+    {
       /* Write the dirty sector */
 
       ret = fat_hwwrite(fs, fs->fs_buffer, fs->fs_currentsector, 1);
       if (ret < 0)
-      {
+        {
           return ret;
-      }
+        }
 
       /* Does the sector lie in the FAT region? */
 
-      if (fs->fs_currentsector < fs->fs_fatbase + fs->fs_nfatsects)
+      if (fs->fs_currentsector >= fs->fs_fatbase &&
-      {
+          fs->fs_currentsector < fs->fs_fatbase + fs->fs_nfatsects)
+        {
           /* Yes, then make the change in the FAT copy as well */
           int i;
 
           for (i = fs->fs_fatnumfats; i >= 2; i--)
-          { 
+            { 
               fs->fs_currentsector += fs->fs_nfatsects;
               ret = fat_hwwrite(fs, fs->fs_buffer, fs->fs_currentsector, 1);
               if (ret < 0)
-              {
+                {
                   return ret;
-              }
+                }
-          }
+            }
-      }
+        }
 
       /* No longer dirty */
 
       fs->fs_dirty = false;
-  }
+    }
   return OK;
 }