[PATCH] ext4: allow larger descriptor size

make block group descriptor larger.

Signed-off-by: Alexandre Ratchov <alexandre.ratchov@bull.net>
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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;
 }
 
 /**