Index: grub-0.97/stage2/fsys_ext2fs.c
===================================================================
--- grub-0.97.orig/stage2/fsys_ext2fs.c
+++ grub-0.97/stage2/fsys_ext2fs.c
@@ -41,6 +41,7 @@ typedef __signed__ short __s16;
 typedef unsigned short __u16;
 typedef __signed__ int __s32;
 typedef unsigned int __u32;
+typedef unsigned long long __u64;
 
 /*
  * Constants relative to the data blocks, from ext2_fs.h
@@ -51,7 +52,7 @@ typedef unsigned int __u32;
 #define EXT2_TIND_BLOCK                 (EXT2_DIND_BLOCK + 1)
 #define EXT2_N_BLOCKS                   (EXT2_TIND_BLOCK + 1)
 
-/* include/linux/ext2_fs.h */
+/* lib/ext2fs/ext2_fs.h from e2fsprogs */
 struct ext2_super_block
   {
     __u32 s_inodes_count;	/* Inodes count */
@@ -61,9 +62,9 @@ struct ext2_super_block
     __u32 s_free_inodes_count;	/* Free inodes count */
     __u32 s_first_data_block;	/* First Data Block */
     __u32 s_log_block_size;	/* Block size */
-    __s32 s_log_frag_size;	/* Fragment size */
+    __s32 s_obso_log_frag_size;	/* Obsoleted Fragment size */
     __u32 s_blocks_per_group;	/* # Blocks per group */
-    __u32 s_frags_per_group;	/* # Fragments per group */
+    __u32 s_obso_frags_per_group;	/* Obsoleted Fragments per group */
     __u32 s_inodes_per_group;	/* # Inodes per group */
     __u32 s_mtime;		/* Mount time */
     __u32 s_wtime;		/* Write time */
@@ -72,7 +73,7 @@ struct ext2_super_block
     __u16 s_magic;		/* Magic signature */
     __u16 s_state;		/* File system state */
     __u16 s_errors;		/* Behaviour when detecting errors */
-    __u16 s_pad;
+    __u16 s_minor_rev_level;	/* minor revision level */
     __u32 s_lastcheck;		/* time of last check */
     __u32 s_checkinterval;	/* max. time between checks */
     __u32 s_creator_os;		/* OS */
@@ -119,15 +120,29 @@ struct ext2_super_block
     __u32 s_hash_seed[4];	/* HTREE hash seed */
     __u8  s_def_hash_version;	/* Default hash version to use */
     __u8  s_jnl_backup_type; 	/* Default type of journal backup */
-    __u16 s_reserved_word_pad;
+    __u16 s_desc_size;		/* size of group descriptor */
     __u32 s_default_mount_opts;
     __u32 s_first_meta_bg;	/* First metablock group */
     __u32 s_mkfs_time;		/* When the filesystem was created */
     __u32 s_jnl_blocks[17]; 	/* Backup of the journal inode */
-    __u32 s_reserved[172];	/* Padding to the end of the block */
-  };
+    /* 64bit desc support valid if EXT4_FEATURE_INCOMPAT_64BIT */
+    __u32 s_blocks_count_hi;	/* Blocks count */
+    __u32 s_r_blocks_count_hi;	/* Reserved blocks count */
+    __u32 s_free_blocks_count_hi; /* Free blocks count */
+    __u16 s_min_extra_isize;	/* All inodes have at least # bytes */
+    __u16 s_max_extra_isize;	/* New inodes should reverve # bytes */
+    __u32 s_flags;		/* Miscellaneous flags */
+    __u16 s_raid_stride;	/* Raid stride */
+    __u16 s_mmp_interval;	/* # seconds to wait MMP checking */
+    __u64 s_mmp_block;		/* Block for multi-mount protection */
+    __u32 s_raid_stripe_width;	/* Blocks on all data disks (N*stride)*/
+    __u8  s_log_groups_per_flex;/* FLEX_BG group size*/
+    __u8  s_reserved_char_pad;
+    __u16 s_reserved_pad;
+    __u32 s_reserved[162];	/* Padding to the end of the block */
+};
 
-struct ext2_group_desc
+struct ext4_group_desc
   {
     __u32 bg_block_bitmap;	/* Blocks bitmap block */
     __u32 bg_inode_bitmap;	/* Inodes bitmap block */
@@ -135,8 +150,18 @@ struct ext2_group_desc
     __u16 bg_free_blocks_count;	/* Free blocks count */
     __u16 bg_free_inodes_count;	/* Free inodes count */
     __u16 bg_used_dirs_count;	/* Directories count */
-    __u16 bg_pad;
-    __u32 bg_reserved[3];
+    __u16 bg_flags;		/* EXT4_BG_flags (INODE_UNINIT, etc) */
+    __u32 bg_reserved[2];		/* Likely block/inode bitmap checksum */
+    __u16 bg_itable_unused;	/* Unused inodes count */
+    __u16 bg_checksum;		/* crc16(sb_uuid+group+desc) */
+    __u32 bg_block_bitmap_hi;	/* Blocks bitmap block MSB */
+    __u32 bg_inode_bitmap_hi;	/* Inodes bitmap block MSB */
+    __u32 bg_inode_table_hi;	/* Inodes table block MSB */
+    __u16 bg_free_blocks_count_hi;/* Free blocks count MSB */
+    __u16 bg_free_inodes_count_hi;/* Free inodes count MSB */
+    __u16 bg_used_dirs_count_hi;	/* Directories count MSB */
+    __u16 bg_itable_unused_hi;	/* Unused inodes count MSB */
+    __u32 bg_reserved2[3];
   };
 
 struct ext2_inode
@@ -174,22 +199,22 @@ struct ext2_inode
     __u32 i_block[EXT2_N_BLOCKS];	/* 40: Pointers to blocks */
     __u32 i_version;		/* File version (for NFS) */
     __u32 i_file_acl;		/* File ACL */
-    __u32 i_dir_acl;		/* Directory ACL */
-    __u32 i_faddr;		/* Fragment address */
+    __u32 i_size_high;
+    __u32 i_obso_faddr;		/* Obsoleted fragment address */
     union
       {
 	struct
 	  {
-	    __u8 l_i_frag;	/* Fragment number */
-	    __u8 l_i_fsize;	/* Fragment size */
-	    __u16 i_pad1;
-	    __u32 l_i_reserved2[2];
+		__u16	l_i_blocks_high; /* were l_i_reserved1 */
+		__u16	l_i_file_acl_high;
+		__u16	l_i_uid_high;	/* these 2 fields */
+		__u16	l_i_gid_high;	/* were reserved2[0] */
+		__u32	l_i_reserved2;
 	  }
 	linux2;
 	struct
 	  {
-	    __u8 h_i_frag;	/* Fragment number */
-	    __u8 h_i_fsize;	/* Fragment size */
+		__u16	h_i_reserved1;	/* Obsoleted fragment number/size which are removed in ext4 */
 	    __u16 h_i_mode_high;
 	    __u16 h_i_uid_high;
 	    __u16 h_i_gid_high;
@@ -198,16 +223,36 @@ struct ext2_inode
 	hurd2;
 	struct
 	  {
-	    __u8 m_i_frag;	/* Fragment number */
-	    __u8 m_i_fsize;	/* Fragment size */
-	    __u16 m_pad1;
+		__u16	h_i_reserved1;	/* Obsoleted fragment number/size which are removed in ext4 */
+		__u16	m_i_file_acl_high;
 	    __u32 m_i_reserved2[2];
 	  }
 	masix2;
       }
     osd2;			/* OS dependent 2 */
+	__u16	i_extra_isize;
+	__u16	i_pad1;
+	__u32  i_ctime_extra;  /* extra Change time      (nsec << 2 | epoch) */
+	__u32  i_mtime_extra;  /* extra Modification time(nsec << 2 | epoch) */
+	__u32  i_atime_extra;  /* extra Access time      (nsec << 2 | epoch) */
+	__u32  i_crtime;       /* File Creation time */
+	__u32  i_crtime_extra; /* extra FileCreationtime (nsec << 2 | epoch) */
+	__u32  i_version_hi;	/* high 32 bits for 64-bit version */
   };
 
+#define EXT4_FEATURE_INCOMPAT_EXTENTS		0x0040 /* extents support */
+#define EXT4_FEATURE_INCOMPAT_64BIT			0x0080 /* grub not supported*/
+#define EXT4_FEATURE_INCOMPAT_MMP           0x0100
+#define EXT4_FEATURE_INCOMPAT_FLEX_BG		0x0200
+
+#define EXT4_HAS_INCOMPAT_FEATURE(sb,mask)			\
+	( sb->s_feature_incompat & mask )
+
+#define EXT4_EXTENTS_FL		0x00080000 /* Inode uses extents */
+#define EXT4_HUGE_FILE_FL	0x00040000 /* Set to each huge file */
+
+#define EXT4_MIN_DESC_SIZE			32
+
 /* linux/limits.h */
 #define NAME_MAX         255	/* # chars in a file name */
 
@@ -225,6 +270,57 @@ struct ext2_dir_entry
     char name[EXT2_NAME_LEN];	/* File name */
   };
 
+/* linux/ext4_fs_extents.h */
+/* This is the extent on-disk structure.
+ * It's used at the bottom of the tree.
+ */
+struct ext4_extent
+  {
+	__u32  ee_block;   /* first logical block extent covers */
+	__u16  ee_len;     /* number of blocks covered by extent */
+	__u16  ee_start_hi;    /* high 16 bits of physical block */
+	__u32  ee_start_lo;    /* low 32 bits of physical block */
+  };
+
+/*
+ * This is index on-disk structure.
+ * It's used at all the levels except the bottom.
+ */
+struct ext4_extent_idx
+  {
+    __u32  ei_block;   /* index covers logical blocks from 'block' */
+    __u32  ei_leaf_lo; /* pointer to the physical block of the next *
+	                     * level. leaf or next index could be there */
+    __u16  ei_leaf_hi; /* high 16 bits of physical block */
+    __u16  ei_unused;
+  };
+
+/*
+ * Each block (leaves and indexes), even inode-stored has header.
+ */
+struct ext4_extent_header
+  {
+    __u16  eh_magic;   /* probably will support different formats */
+    __u16  eh_entries; /* number of valid entries */
+    __u16  eh_max;     /* capacity of store in entries */
+    __u16  eh_depth;   /* has tree real underlying blocks? */
+    __u32  eh_generation;  /* generation of the tree */
+  };
+
+#define EXT4_EXT_MAGIC      (0xf30a)
+#define EXT_FIRST_EXTENT(__hdr__) \
+    ((struct ext4_extent *) (((char *) (__hdr__)) +     \
+                 sizeof(struct ext4_extent_header)))
+#define EXT_FIRST_INDEX(__hdr__) \
+    ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \
+                 sizeof(struct ext4_extent_header)))
+#define EXT_LAST_EXTENT(__hdr__) \
+    (EXT_FIRST_EXTENT((__hdr__)) + (__u16)((__hdr__)->eh_entries) - 1)
+#define EXT_LAST_INDEX(__hdr__) \
+    (EXT_FIRST_INDEX((__hdr__)) + (__u16)((__hdr__)->eh_entries) - 1)
+
+
+
 /* linux/ext2fs.h */
 /*
  * EXT2_DIR_PAD defines the directory entries boundaries
@@ -271,8 +367,17 @@ struct ext2_dir_entry
 /* kind of from ext2/super.c */
 #define EXT2_BLOCK_SIZE(s)	(1 << EXT2_BLOCK_SIZE_BITS(s))
 /* linux/ext2fs.h */
+/* sizeof(struct ext2_group_desc) is changed in ext4
+ * in kernel code, ext2/3 uses sizeof(struct ext2_group_desc) to calculate
+ * number of desc per block, while ext4 uses superblock->s_desc_size in stead
+ * superblock->s_desc_size is not available in ext2/3
+ * */
+#define EXT2_DESC_SIZE(s) \
+	(EXT4_HAS_INCOMPAT_FEATURE(s,EXT4_FEATURE_INCOMPAT_64BIT)? \
+	s->s_desc_size : EXT4_MIN_DESC_SIZE)
 #define EXT2_DESC_PER_BLOCK(s) \
-     (EXT2_BLOCK_SIZE(s) / sizeof (struct ext2_group_desc))
+	(EXT2_BLOCK_SIZE(s) / EXT2_DESC_SIZE(s))
+
 /* linux/stat.h */
 #define S_IFMT  00170000
 #define S_IFLNK  0120000
@@ -434,6 +539,122 @@ ext2fs_block_map (int logical_block)
     [logical_block & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)];
 }
 
+/* extent binary search index
+ * find closest index in the current level extent tree
+ * kind of from ext4_ext_binsearch_idx in ext4/extents.c
+ */
+static struct ext4_extent_idx*
+ext4_ext_binsearch_idx(struct ext4_extent_header* eh, int logical_block)
+{
+  struct ext4_extent_idx *r, *l, *m;
+  l = EXT_FIRST_INDEX(eh) + 1;
+  r = EXT_LAST_INDEX(eh);
+  while (l <= r)
+    {
+	  m = l + (r - l) / 2;
+	  if (logical_block < m->ei_block)
+		  r = m - 1;
+	  else
+		  l = m + 1;
+	}
+  return (struct ext4_extent_idx*)(l - 1);
+}
+
+/* extent binary search
+ * find closest extent in the leaf level
+ * kind of from ext4_ext_binsearch in ext4/extents.c
+ */
+static struct ext4_extent*
+ext4_ext_binsearch(struct ext4_extent_header* eh, int logical_block)
+{
+  struct ext4_extent *r, *l, *m;
+  l = EXT_FIRST_EXTENT(eh) + 1;
+  r = EXT_LAST_EXTENT(eh);
+  while (l <= r)
+    {
+	  m = l + (r - l) / 2;
+	  if (logical_block < m->ee_block)
+		  r = m - 1;
+	  else
+		  l = m + 1;
+	}
+  return (struct ext4_extent*)(l - 1);
+}
+
+/* Maps extents enabled logical block into physical block via an inode.
+ * EXT4_HUGE_FILE_FL should be checked before calling this.
+ */
+static int
+ext4fs_block_map (int logical_block)
+{
+  struct ext4_extent_header *eh;
+  struct ext4_extent *ex, *extent;
+  struct ext4_extent_idx *ei, *index;
+  int depth;
+  int i;
+
+#ifdef E2DEBUG
+  unsigned char *i;
+  for (i = (unsigned char *) INODE;
+       i < ((unsigned char *) INODE + sizeof (struct ext2_inode));
+       i++)
+    {
+      printf ("%c", "0123456789abcdef"[*i >> 4]);
+      printf ("%c", "0123456789abcdef"[*i % 16]);
+      if (!((i + 1 - (unsigned char *) INODE) % 16))
+	{
+	  printf ("\n");
+	}
+      else
+	{
+	  printf (" ");
+	}
+    }
+  printf ("logical block %d\n", logical_block);
+#endif /* E2DEBUG */
+  eh = (struct ext4_extent_header*)INODE->i_block;
+  if (eh->eh_magic != EXT4_EXT_MAGIC)
+  {
+          errnum = ERR_FSYS_CORRUPT;
+          return -1;
+  }
+  while((depth = eh->eh_depth) != 0)
+  	{ /* extent index */
+	  if (eh->eh_magic != EXT4_EXT_MAGIC)
+	  {
+	          errnum = ERR_FSYS_CORRUPT;
+		  return -1;
+	  }
+	  ei = ext4_ext_binsearch_idx(eh, logical_block);
+	  if (ei->ei_leaf_hi)
+	{/* 64bit physical block number not supported */
+	  errnum = ERR_FILELENGTH;
+	  return -1;
+	}
+	  if (!ext2_rdfsb(ei->ei_leaf_lo, DATABLOCK1))
+	{
+	  errnum = ERR_FSYS_CORRUPT;
+	  return -1;
+	}
+	  eh = (struct ext4_extent_header*)DATABLOCK1;
+  	}
+
+  /* depth==0, we come to the leaf */
+  ex = ext4_ext_binsearch(eh, logical_block);
+  if (ex->ee_start_hi)
+	{/* 64bit physical block number not supported */
+	  errnum = ERR_FILELENGTH;
+	  return -1;
+	}
+  if ((ex->ee_block + ex->ee_len) < logical_block)
+	{
+	  errnum = ERR_FSYS_CORRUPT;
+	  return -1;
+	}
+  return ex->ee_start_lo + logical_block - ex->ee_block;
+
+}
+
 /* preconditions: all preconds of ext2fs_block_map */
 int
 ext2fs_read (char *buf, int len)
@@ -468,6 +689,11 @@ ext2fs_read (char *buf, int len)
       /* find the (logical) block component of our location */
       logical_block = filepos >> EXT2_BLOCK_SIZE_BITS (SUPERBLOCK);
       offset = filepos & (EXT2_BLOCK_SIZE (SUPERBLOCK) - 1);
+      /* map extents enabled logical block number to physical fs on-disk block number */
+      if (EXT4_HAS_INCOMPAT_FEATURE(SUPERBLOCK,EXT4_FEATURE_INCOMPAT_EXTENTS)
+                    && INODE->i_flags & EXT4_EXTENTS_FL)
+          map = ext4fs_block_map (logical_block);
+      else
       map = ext2fs_block_map (logical_block);
 #ifdef E2DEBUG
       printf ("map=%d\n", map);
@@ -552,7 +778,7 @@ ext2fs_dir (char *dirname)
   int desc;			/* index within that group */
   int ino_blk;			/* fs pointer of the inode's information */
   int str_chk = 0;		/* used to hold the results of a string compare */
-  struct ext2_group_desc *gdp;
+  struct ext4_group_desc *ext4_gdp;
   struct ext2_inode *raw_inode;	/* inode info corresponding to current_ino */
 
   char linkbuf[PATH_MAX];	/* buffer for following symbolic links */
@@ -598,8 +824,15 @@ ext2fs_dir (char *dirname)
 	{
 	  return 0;
 	}
-      gdp = GROUP_DESC;
-      ino_blk = gdp[desc].bg_inode_table +
+	  ext4_gdp = (struct ext4_group_desc *)( (__u8*)GROUP_DESC +
+			  		desc * EXT2_DESC_SIZE(SUPERBLOCK));
+	  if (EXT4_HAS_INCOMPAT_FEATURE(SUPERBLOCK, EXT4_FEATURE_INCOMPAT_64BIT)
+		&& (! ext4_gdp->bg_inode_table_hi))
+	{/* 64bit itable not supported */
+	  errnum = ERR_FILELENGTH;
+	  return -1;
+	}
+      ino_blk = ext4_gdp->bg_inode_table +
 	(((current_ino - 1) % (SUPERBLOCK->s_inodes_per_group))
 	 >> log2 (EXT2_INODES_PER_BLOCK (SUPERBLOCK)));
 #ifdef E2DEBUG
@@ -676,7 +909,10 @@ ext2fs_dir (char *dirname)
 	    }
 	  linkbuf[filemax + len] = '\0';
 
-	  /* Read the symlink data. */
+	  /* Read the symlink data.
+	   * Slow symlink is extents enabled
+	   * But since grub_read invokes ext2fs_read, nothing to change here
+	   */
 	  if (! ext2_is_fast_symlink ())
 	    {
 	      /* Read the necessary blocks, and reset the file pointer. */
@@ -687,7 +923,9 @@ ext2fs_dir (char *dirname)
 	    }
 	  else
 	    {
-	      /* Copy the data directly from the inode. */
+	      /* Copy the data directly from the inode.
+	       * Fast symlink is not extents enabled
+	       */
 	      len = filemax;
 	      memmove (linkbuf, (char *) INODE->i_block, len);
 	    }
@@ -721,6 +959,13 @@ ext2fs_dir (char *dirname)
 	      errnum = ERR_BAD_FILETYPE;
 	      return 0;
 	    }
+	  /* if file is too large, just stop and report an error*/
+	  if ( (INODE->i_flags & EXT4_HUGE_FILE_FL) && !(INODE->i_size_high))
+	    {
+		  /* file too large, stop reading */
+		  errnum = ERR_FILELENGTH;
+		  return 0;
+	    }
 
 	  filemax = (INODE->i_size);
 	  return 1;
@@ -775,17 +1020,28 @@ ext2fs_dir (char *dirname)
 	    }
 
 	  /* else, find the (logical) block component of our location */
+	  /* ext4 logical block number the same as ext2/3 */
 	  blk = loc >> EXT2_BLOCK_SIZE_BITS (SUPERBLOCK);
 
 	  /* we know which logical block of the directory entry we are looking
 	     for, now we have to translate that to the physical (fs) block on
 	     the disk */
+	  /* map extents enabled logical block number to physical fs on-disk block number */
+	  if (EXT4_HAS_INCOMPAT_FEATURE(SUPERBLOCK,EXT4_FEATURE_INCOMPAT_EXTENTS)
+                        && INODE->i_flags & EXT4_EXTENTS_FL)
+              map = ext4fs_block_map (blk);
+	  else
 	  map = ext2fs_block_map (blk);
 #ifdef E2DEBUG
 	  printf ("fs block=%d\n", map);
 #endif /* E2DEBUG */
 	  mapblock2 = -1;
-	  if ((map < 0) || !ext2_rdfsb (map, DATABLOCK2))
+	  if (map < 0)
+	  {
+	      *rest = ch;
+	      return 0;
+	  }
+          if (!ext2_rdfsb (map, DATABLOCK2))
 	    {
 	      errnum = ERR_FSYS_CORRUPT;
 	      *rest = ch;
