ext4: clarify description of ac_g_ex in struct ext4_allocation_context

Signed-off-by: Coly Li <bosong.ly@taobao.com>
Cc: Alex Tomas <alex@clusterfs.com>
Cc: Theodore Tso <tytso@google.com>
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index b619322..22bd4d7 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -169,7 +169,7 @@
 	/* original request */
 	struct ext4_free_extent ac_o_ex;
 
-	/* goal request (after normalization) */
+	/* goal request (normalized ac_o_ex) */
 	struct ext4_free_extent ac_g_ex;
 
 	/* the best found extent */