f2fs: change get_new_data_page to pass a locked node page

This patch is for passing a locked node page to get_dnode_of_data.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 05fb5c6..af74549 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -280,8 +280,8 @@
  * Also, caller should grab and release a mutex by calling mutex_lock_op() and
  * mutex_unlock_op().
  */
-struct page *get_new_data_page(struct inode *inode, pgoff_t index,
-						bool new_i_size)
+struct page *get_new_data_page(struct inode *inode,
+		struct page *npage, pgoff_t index, bool new_i_size)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 	struct address_space *mapping = inode->i_mapping;
@@ -289,18 +289,20 @@
 	struct dnode_of_data dn;
 	int err;
 
-	set_new_dnode(&dn, inode, NULL, NULL, 0);
+	set_new_dnode(&dn, inode, npage, npage, 0);
 	err = get_dnode_of_data(&dn, index, ALLOC_NODE);
 	if (err)
 		return ERR_PTR(err);
 
 	if (dn.data_blkaddr == NULL_ADDR) {
 		if (reserve_new_block(&dn)) {
-			f2fs_put_dnode(&dn);
+			if (!npage)
+				f2fs_put_dnode(&dn);
 			return ERR_PTR(-ENOSPC);
 		}
 	}
-	f2fs_put_dnode(&dn);
+	if (!npage)
+		f2fs_put_dnode(&dn);
 repeat:
 	page = grab_cache_page(mapping, index);
 	if (!page)