[LIBFSIMAGE] Support 256 byte inodes on ext3

Patch taken from Debian grub package version 0.97-32.
See http://bugs.debian.org/463236 & http://bugs.debian.org/463123

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>

tools/libfsimage/ext2fs/fsys_ext2fs.c

@@ -77,7 +77,52 @@ struct ext2_super_block
     __u32 s_rev_level;		/* Revision level */
     __u16 s_def_resuid;		/* Default uid for reserved blocks */
     __u16 s_def_resgid;		/* Default gid for reserved blocks */
-    __u32 s_reserved[235];	/* Padding to the end of the block */
+    /*
+     * These fields are for EXT2_DYNAMIC_REV superblocks only.
+     *
+     * Note: the difference between the compatible feature set and
+     * the incompatible feature set is that if there is a bit set
+     * in the incompatible feature set that the kernel doesn't
+     * know about, it should refuse to mount the filesystem.
+     *
+     * e2fsck's requirements are more strict; if it doesn't know
+     * about a feature in either the compatible or incompatible
+     * feature set, it must abort and not try to meddle with
+     * things it doesn't understand...
+     */
+    __u32 s_first_ino;		/* First non-reserved inode */
+    __u16 s_inode_size;		/* size of inode structure */
+    __u16 s_block_group_nr;	/* block group # of this superblock */
+    __u32 s_feature_compat;	/* compatible feature set */
+    __u32 s_feature_incompat;	/* incompatible feature set */
+    __u32 s_feature_ro_compat;	/* readonly-compatible feature set */
+    __u8  s_uuid[16];		/* 128-bit uuid for volume */
+    char  s_volume_name[16];	/* volume name */
+    char  s_last_mounted[64];	/* directory where last mounted */
+    __u32 s_algorithm_usage_bitmap; /* For compression */
+    /*
+     * Performance hints.  Directory preallocation should only
+     * happen if the EXT2_FEATURE_COMPAT_DIR_PREALLOC flag is on.
+     */
+    __u8  s_prealloc_blocks;	/* Nr of blocks to try to preallocate*/
+    __u8  s_prealloc_dir_blocks;	/* Nr to preallocate for dirs */
+    __u16 s_reserved_gdt_blocks;/* Per group table for online growth */
+    /*
+     * Journaling support valid if EXT2_FEATURE_COMPAT_HAS_JOURNAL set.
+     */
+    __u8 s_journal_uuid[16];	/* uuid of journal superblock */
+    __u32 s_journal_inum;	/* inode number of journal file */
+    __u32 s_journal_dev;	/* device number of journal file */
+    __u32 s_last_orphan;	/* start of list of inodes to delete */
+    __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;
+    __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 */
   };
 
 struct ext2_group_desc
@@ -216,6 +261,9 @@ struct ext2_dir_entry
 #define EXT2_ADDR_PER_BLOCK(s)          (EXT2_BLOCK_SIZE(s) / sizeof (__u32))
 #define EXT2_ADDR_PER_BLOCK_BITS(s)		(log2(EXT2_ADDR_PER_BLOCK(s)))
 
+#define EXT2_INODE_SIZE(s)		(SUPERBLOCK->s_inode_size)
+#define EXT2_INODES_PER_BLOCK(s)	(EXT2_BLOCK_SIZE(s)/EXT2_INODE_SIZE(s))
+
 /* linux/ext2_fs.h */
 #define EXT2_BLOCK_SIZE_BITS(s)        ((s)->s_log_block_size + 10)
 /* kind of from ext2/super.c */
@@ -537,7 +585,7 @@ ext2fs_dir (fsi_file_t *ffi, char *dirname)
       gdp = GROUP_DESC;
       ino_blk = gdp[desc].bg_inode_table +
 	(((current_ino - 1) % (SUPERBLOCK->s_inodes_per_group))
-	 >> log2 (EXT2_BLOCK_SIZE (SUPERBLOCK) / sizeof (struct ext2_inode)));
+	 >> log2 (EXT2_INODES_PER_BLOCK (SUPERBLOCK)));
 #ifdef E2DEBUG
       printf ("inode table fsblock=%d\n", ino_blk);
 #endif /* E2DEBUG */
@@ -549,13 +597,12 @@ ext2fs_dir (fsi_file_t *ffi, char *dirname)
       /* reset indirect blocks! */
       mapblock2 = mapblock1 = -1;
 
-      raw_inode = INODE +
-	((current_ino - 1)
-	 & (EXT2_BLOCK_SIZE (SUPERBLOCK) / sizeof (struct ext2_inode) - 1));
+      raw_inode = (struct ext2_inode *)((char *)INODE +
+	((current_ino - 1) & (EXT2_INODES_PER_BLOCK (SUPERBLOCK) - 1)) *
+	EXT2_INODE_SIZE (SUPERBLOCK));
 #ifdef E2DEBUG
       printf ("ipb=%d, sizeof(inode)=%d\n",
-	      (EXT2_BLOCK_SIZE (SUPERBLOCK) / sizeof (struct ext2_inode)),
-	      sizeof (struct ext2_inode));
+	      EXT2_INODES_PER_BLOCK (SUPERBLOCK), EXT2_INODE_SIZE (SUPERBLOCK));
       printf ("inode=%x, raw_inode=%x\n", INODE, raw_inode);
       printf ("offset into inode table block=%d\n", (int) raw_inode - (int) INODE);
       for (i = (unsigned char *) INODE; i <= (unsigned char *) raw_inode;