diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index df77ea8..3dacb12 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -74,10 +74,12 @@
 		return NULL;
 	}
 
-	desc = (struct ext4_group_desc *) sbi->s_group_desc[group_desc]->b_data;
+	desc = (struct ext4_group_desc *)(
+		(__u8 *)sbi->s_group_desc[group_desc]->b_data +
+		offset * EXT4_DESC_SIZE(sb));
 	if (bh)
 		*bh = sbi->s_group_desc[group_desc];
-	return desc + offset;
+	return desc;
 }
 
 /**
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c05dc57..d03e7d8 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2432,14 +2432,16 @@
 		return 0;
 	}
 
-	gdp = (struct ext4_group_desc *)bh->b_data;
+	gdp = (struct ext4_group_desc *)((__u8 *)bh->b_data +
+		desc * EXT4_DESC_SIZE(sb));
 	/*
 	 * Figure out the offset within the block group inode table
 	 */
 	offset = ((ino - 1) % EXT4_INODES_PER_GROUP(sb)) *
 		EXT4_INODE_SIZE(sb);
-	block = ext4_inode_table(gdp + desc) +
-			(offset >> EXT4_BLOCK_SIZE_BITS(sb));
+	block = ext4_inode_table(gdp) + (offset >> EXT4_BLOCK_SIZE_BITS(sb));
+
+
 
 	iloc->block_group = block_group;
 	iloc->offset = offset & (EXT4_BLOCK_SIZE(sb) - 1);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index d844175..bc8848b 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1268,7 +1268,8 @@
 			return 0;
 		}
 		first_block += EXT4_BLOCKS_PER_GROUP(sb);
-		gdp++;
+		gdp = (struct ext4_group_desc *)
+			((__u8 *)gdp + EXT4_DESC_SIZE(sb));
 	}
 
 	ext4_free_blocks_count_set(sbi->s_es, ext4_count_free_blocks(sb));
@@ -1619,7 +1620,18 @@
 		       sbi->s_frag_size, blocksize);
 		goto failed_mount;
 	}
-	sbi->s_frags_per_block = 1;
+	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
+	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
+		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE ||
+		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
+		    sbi->s_desc_size & (sbi->s_desc_size - 1)) {
+			printk(KERN_ERR
+			       "EXT4-fs: unsupported descriptor size %ld\n",
+			       sbi->s_desc_size);
+			goto failed_mount;
+		}
+	} else
+		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 	sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
@@ -1630,7 +1642,7 @@
 		goto cantfind_ext4;
 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
 					sbi->s_inodes_per_block;
-	sbi->s_desc_per_block = blocksize / sizeof(struct ext4_group_desc);
+	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
 	sbi->s_sbh = bh;
 	sbi->s_mount_state = le16_to_cpu(es->s_state);
 	sbi->s_addr_per_block_bits = log2(EXT4_ADDR_PER_BLOCK(sb));