f2fs: export dir operations for inline dir

This patch exports some dir operations for inline dir, additionally introduces
f2fs_drop_nlink from f2fs_delete_entry for reusing by inline dir function.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 0d2526e..6e67f2b 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -223,7 +223,7 @@
 		f2fs_put_page(page, 0);
 		goto fail;
 	}
-	f2fs_delete_entry(de, page, inode);
+	f2fs_delete_entry(de, page, dir, inode);
 	f2fs_unlock_op(sbi);
 
 	/* In order to evict this inode, we set it dirty */
@@ -435,7 +435,7 @@
 	old_inode->i_ctime = CURRENT_TIME;
 	mark_inode_dirty(old_inode);
 
-	f2fs_delete_entry(old_entry, old_page, NULL);
+	f2fs_delete_entry(old_entry, old_page, old_dir, NULL);
 
 	if (old_dir_entry) {
 		if (old_dir != new_dir) {