f2fs: do not write any node pages related to orphan inodes

We should not write node pages when deleting orphan inodes.
In order to do that, we can eaisly set POR_DOING flag earlier before entering
orphan inode routine.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index d2ef0c9..faec2ca 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -545,14 +545,12 @@
 
 	INIT_LIST_HEAD(&inode_list);
 
-	/* step #1: find fsynced inode numbers */
-	set_sbi_flag(sbi, SBI_POR_DOING);
-
 	/* prevent checkpoint */
 	mutex_lock(&sbi->cp_mutex);
 
 	blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
 
+	/* step #1: find fsynced inode numbers */
 	err = find_fsync_dnodes(sbi, &inode_list);
 	if (err)
 		goto out;