From 3c9fc981a2aa27a6b2456a7a8e68cd721dea8951 Mon Sep 17 00:00:00 2001
From: robertmh <robertmh@localhost>
Date: Fri, 5 Sep 2003 01:36:58 +0000
Subject: [PATCH] * stage2/fsys_fat.c: Fix missdetection of ext2fs as fatfs.

---
 ChangeLog         |  4 ++++
 stage2/fsys_fat.c | 26 ++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 83590d0a0..ae04c0f53 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2003-09-05  KB Sriram  <mail_kb@yahoo.com>
+
+	* stage2/fsys_fat.c: Fix missdetection of ext2fs as fatfs.
+
 2003-09-05  Robert Millan  <robertmh@gnu.org>
 
 	* docs/menu.lst (GNU/Linux): Add commented initrd command, which is
diff --git a/stage2/fsys_fat.c b/stage2/fsys_fat.c
index 286d4a45f..c97eb3c16 100644
--- a/stage2/fsys_fat.c
+++ b/stage2/fsys_fat.c
@@ -67,6 +67,7 @@ int
 fat_mount (void)
 {
   struct fat_bpb bpb;
+  __u32 magic, first_fat;
   
   /* Check partition type for harddisk */
   if (((current_drive & 0x80) || (current_slice != 0))
@@ -161,6 +162,31 @@ fat_mount (void)
  	  > FAT_SUPER->fat_length))
     return 0;
   
+  /* kbs: Media check on first FAT entry [ported from PUPA] */
+
+  if (!devread(FAT_SUPER->fat_offset, 0,
+               sizeof(first_fat), (char *)&first_fat))
+    return 0;
+
+  if (FAT_SUPER->fat_size == 8)
+    {
+      first_fat &= 0x0fffffff;
+      magic = 0x0fffff00;
+    }
+  else if (FAT_SUPER->fat_size == 4)
+    {
+      first_fat &= 0x0000ffff;
+      magic = 0xff00;
+    }
+  else
+    {
+      first_fat &= 0x00000fff;
+      magic = 0x0f00;
+    }
+
+  if (first_fat != (magic | bpb.media))
+    return 0;
+
   FAT_SUPER->cached_fat = - 2 * FAT_CACHE_SIZE;
   return 1;
 }