Index: linux-2.6.22-rc4/fs/ext4/super.c
===================================================================
--- linux-2.6.22-rc4.orig/fs/ext4/super.c
+++ linux-2.6.22-rc4/fs/ext4/super.c
@@ -1298,9 +1298,12 @@ __le16 ext4_group_desc_csum(struct ext4_
 		offset += sizeof(gdp->bg_checksum); /* skip checksum */
 		/*BUG_ON(offset != sizeof(*gdp)); /* XXX handle s_desc_size */
 		/* for checksum of struct ext4_group_desc do the rest...*/
-		if (offset < sbi->s_es->s_desc_size) {
+		if ((sbi->s_es->s_feature_incompat &
+		     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) && 
+		    offset < le16_to_cpu(sbi->s_es->s_desc_size)) {
 			crc = crc16(crc, (__u8 *)gdp + offset,
-				    sbi->s_es->s_desc_size - offset);
+				    le16_to_cpu(sbi->s_es->s_desc_size)
+					- offset);
 		} 
 	}
 
Index: linux-2.6.22-rc4/include/linux/ext4_fs.h
===================================================================
--- linux-2.6.22-rc4.orig/include/linux/ext4_fs.h
+++ linux-2.6.22-rc4/include/linux/ext4_fs.h
@@ -687,11 +687,11 @@ static inline int ext4_valid_inum(struct
 #define EXT4_FEATURE_COMPAT_EXT_ATTR		0x0008
 #define EXT4_FEATURE_COMPAT_RESIZE_INODE	0x0010
 #define EXT4_FEATURE_COMPAT_DIR_INDEX		0x0020
-#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM		0x0040
 
 #define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
 #define EXT4_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
 #define EXT4_FEATURE_RO_COMPAT_BTREE_DIR	0x0004
+#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM		0x0010
 #define EXT4_FEATURE_RO_COMPAT_DIR_NLINK	0x0020
 #define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE	0x0040