Revert "ubifs: dirty_cow_znode: Fix memleak in error handling path"

This reverts commit 122deabf (ubifs: dirty_cow_znode: Fix memleak
in error handling path).
After commit 122deabf applied, if insert_old_idx() failed, old
index neither exists in TNC nor in old-index tree. Which means that
old index node could be overwritten in layout_leb_in_gaps(), then
ubifs image will be corrupted in power-cut.

Fixes: 122deabf (ubifs: dirty_cow_znode: Fix memleak ... path)
Cc: stable@vger.kernel.org
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

fs/ubifs/tnc.c

@@ -267,18 +267,11 @@ static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c,
 	if (zbr->len) {
 		err = insert_old_idx(c, zbr->lnum, zbr->offs);
 		if (unlikely(err))
-			/*
-			 * Obsolete znodes will be freed by tnc_destroy_cnext()
-			 * or free_obsolete_znodes(), copied up znodes should
-			 * be added back to tnc and freed by
-			 * ubifs_destroy_tnc_subtree().
-			 */
-			goto out;
+			return ERR_PTR(err);
 		err = add_idx_dirt(c, zbr->lnum, zbr->len);
 	} else
 		err = 0;
 
-out:
 	zbr->znode = zn;
 	zbr->lnum = 0;
 	zbr->offs = 0;