bcachefs: Handle transaction restarts in bch2_blacklist_entries_gc()

It shouldn't be necessary when we're only using a single iterator and
not doing updates, but that's harder to debug at the moment.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/journal_seq_blacklist.c

@@ -253,12 +253,21 @@ void bch2_blacklist_entries_gc(struct work_struct *work)
 		struct btree_iter iter;
 		struct btree *b;
 
-		for_each_btree_node(&trans, iter, i, POS_MIN,
-				    BTREE_ITER_PREFETCH, b, ret)
-			if (test_bit(BCH_FS_STOPPING, &c->flags)) {
-				bch2_trans_exit(&trans);
-				return;
-			}
+		bch2_trans_node_iter_init(&trans, &iter, i, POS_MIN,
+					  0, 0, BTREE_ITER_PREFETCH);
+retry:
+		bch2_trans_begin(&trans);
+
+		b = bch2_btree_iter_peek_node(&iter);
+
+		while (!(ret = PTR_ERR_OR_ZERO(b)) &&
+		       b &&
+		       !test_bit(BCH_FS_STOPPING, &c->flags))
+			b = bch2_btree_iter_next_node(&iter);
+
+		if (ret == -EINTR)
+			goto retry;
+
 		bch2_trans_iter_exit(&trans, &iter);
 	}
 

fs/bcachefs/migrate.c

@@ -136,6 +136,7 @@ static int bch2_dev_metadata_drop(struct bch_fs *c, unsigned dev_idx, int flags)
 		bch2_trans_node_iter_init(&trans, &iter, id, POS_MIN, 0, 0,
 					  BTREE_ITER_PREFETCH);
 retry:
+		ret = 0;
 		while (bch2_trans_begin(&trans),
 		       (b = bch2_btree_iter_peek_node(&iter)) &&
 		       !(ret = PTR_ERR_OR_ZERO(b))) {

fs/bcachefs/move.c

@@ -886,6 +886,7 @@ static int bch2_move_btree(struct bch_fs *c,
 		bch2_trans_node_iter_init(&trans, &iter, id, POS_MIN, 0, 0,
 					  BTREE_ITER_PREFETCH);
 retry:
+		ret = 0;
 		while (bch2_trans_begin(&trans),
 		       (b = bch2_btree_iter_peek_node(&iter)) &&
 		       !(ret = PTR_ERR_OR_ZERO(b))) {