ext4: isolate ext4_extents.h file

After applied the commit (4a092d73), we have reduced the number of
source files that need to #include ext4_extents.h.  But we can do
better.

This commit defines ext4_zeroout_es() in extents.c and move
EXT_MAX_BLOCKS into ext4.h in order not to include ext4_extents.h in
indirect.c and ioctl.c.  Meanwhile we just need to include this file in
extent_status.c when ES_AGGRESSIVE_TEST is defined.  Otherwise, this
commit removes a duplicated declaration in trace/events/ext4.h.

After applied this patch, we just need to include ext4_extents.h file
in {super,migrate,move_extents,extents}.c, and it is easy for us to
define a new extent disk layout.

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 0e88a36..2d1bdbe 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -13,7 +13,6 @@
 #include <linux/list_sort.h>
 #include "ext4.h"
 #include "extents_status.h"
-#include "ext4_extents.h"
 
 #include <trace/events/ext4.h>
 
@@ -409,6 +408,8 @@
 }
 
 #ifdef ES_AGGRESSIVE_TEST
+#include "ext4_extents.h"	/* Needed when ES_AGGRESSIVE_TEST is defined */
+
 static void ext4_es_insert_extent_ext_check(struct inode *inode,
 					    struct extent_status *es)
 {
@@ -903,23 +904,6 @@
 	return err;
 }
 
-int ext4_es_zeroout(struct inode *inode, struct ext4_extent *ex)
-{
-	ext4_lblk_t  ee_block;
-	ext4_fsblk_t ee_pblock;
-	unsigned int ee_len;
-
-	ee_block  = le32_to_cpu(ex->ee_block);
-	ee_len    = ext4_ext_get_actual_len(ex);
-	ee_pblock = ext4_ext_pblock(ex);
-
-	if (ee_len == 0)
-		return 0;
-
-	return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
-				     EXTENT_STATUS_WRITTEN);
-}
-
 static int ext4_inode_touch_time_cmp(void *priv, struct list_head *a,
 				     struct list_head *b)
 {