btrfs: open code set_extent_defrag

The helper is used only once.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/defrag.c

@@ -1040,7 +1040,9 @@ static int defrag_one_locked_target(struct btrfs_inode *inode,
 	clear_extent_bit(&inode->io_tree, start, start + len - 1,
 			 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
 			 EXTENT_DEFRAG, cached_state);
-	set_extent_defrag(&inode->io_tree, start, start + len - 1, cached_state);
+	set_extent_bit(&inode->io_tree, start, start + len - 1,
+		       EXTENT_DELALLOC | EXTENT_DEFRAG,
+		       cached_state, GFP_NOFS);
 
 	/* Update the page status */
 	for (i = start_index - first_index; i <= last_index - first_index; i++) {

fs/btrfs/extent-io-tree.h

@@ -202,14 +202,6 @@ static inline int set_extent_delalloc(struct extent_io_tree *tree, u64 start,
 			      cached_state, GFP_NOFS);
 }
 
-static inline int set_extent_defrag(struct extent_io_tree *tree, u64 start,
-		u64 end, struct extent_state **cached_state)
-{
-	return set_extent_bit(tree, start, end,
-			      EXTENT_DELALLOC | EXTENT_DEFRAG,
-			      cached_state, GFP_NOFS);
-}
-
 static inline int set_extent_new(struct extent_io_tree *tree, u64 start,
 		u64 end)
 {