ext4: replace MAX_DEFRAG_SIZE with EXT_MAX_BLOCK

There's no reason to redefine the maximum allowable offset
in an extent-based file just for defrag; 
EXT_MAX_BLOCK already does this.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h
index 9538633..61652f1 100644
--- a/fs/ext4/ext4_extents.h
+++ b/fs/ext4/ext4_extents.h
@@ -137,6 +137,7 @@
 #define EXT_BREAK      1
 #define EXT_REPEAT     2
 
+/* Maximum logical block in a file; ext4_extent's ee_block is __le32 */
 #define EXT_MAX_BLOCK	0xffffffff
 
 /*