f2fs: call mark_inode_dirty to flush dirty pages

If a dentry page is updated, we should call mark_inode_dirty to add the inode
into the dirty list, so that its dentry pages are flushed to the disk.
Otherwise, the inode can be evicted without flush.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index a68838d..3d32f29 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -430,6 +430,7 @@
 		if (old_dir_entry)
 			drop_nlink(new_inode);
 		drop_nlink(new_inode);
+		mark_inode_dirty(new_inode);
 
 		if (!new_inode->i_nlink)
 			add_orphan_inode(sbi, new_inode->i_ino);
@@ -459,11 +460,13 @@
 			f2fs_set_link(old_inode, old_dir_entry,
 						old_dir_page, new_dir);
 			F2FS_I(old_inode)->i_pino = new_dir->i_ino;
+			update_inode_page(old_inode);
 		} else {
 			kunmap(old_dir_page);
 			f2fs_put_page(old_dir_page, 0);
 		}
 		drop_nlink(old_dir);
+		mark_inode_dirty(old_dir);
 		update_inode_page(old_dir);
 	}