bcachefs: Switch data_update path to snapshot_id_list

snapshots_seen is becoming private to fsck, and snapshot_id_list is
actually what the data update path needs.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/data_update.c

@@ -22,13 +22,13 @@ static int insert_snapshot_whiteouts(struct btree_trans *trans,
 	struct bch_fs *c = trans->c;
 	struct btree_iter iter, update_iter;
 	struct bkey_s_c k;
-	struct snapshots_seen s;
+	snapshot_id_list s;
 	int ret;
 
 	if (!btree_type_has_snapshots(id))
 		return 0;
 
-	snapshots_seen_init(&s);
+	darray_init(&s);
 
 	if (!bkey_cmp(old_pos, new_pos))
 		return 0;
@@ -40,7 +40,6 @@ static int insert_snapshot_whiteouts(struct btree_trans *trans,
 			     BTREE_ITER_NOT_EXTENTS|
 			     BTREE_ITER_ALL_SNAPSHOTS);
 	while (1) {
-next:
 		k = bch2_btree_iter_prev(&iter);
 		ret = bkey_err(k);
 		if (ret)
@@ -51,11 +50,9 @@ static int insert_snapshot_whiteouts(struct btree_trans *trans,
 
 		if (bch2_snapshot_is_ancestor(c, k.k->p.snapshot, old_pos.snapshot)) {
 			struct bkey_i *update;
-			u32 *i;
 
-			darray_for_each(s.ids, i)
-				if (bch2_snapshot_is_ancestor(c, k.k->p.snapshot, *i))
-					goto next;
+			if (snapshot_list_has_ancestor(c, &s, k.k->p.snapshot))
+				continue;
 
 			update = bch2_trans_kmalloc(trans, sizeof(struct bkey_i));
 
@@ -78,13 +75,13 @@ static int insert_snapshot_whiteouts(struct btree_trans *trans,
 			if (ret)
 				break;
 
-			ret = snapshots_seen_add(c, &s, k.k->p.snapshot);
+			ret = snapshot_list_add(c, &s, k.k->p.snapshot);
 			if (ret)
 				break;
 		}
 	}
 	bch2_trans_iter_exit(trans, &iter);
-	darray_exit(&s.ids);
+	darray_exit(&s);
 
 	return ret;
 }

fs/bcachefs/subvolume.c

@@ -565,13 +565,6 @@ int bch2_snapshot_node_create(struct btree_trans *trans, u32 parent,
 	return ret;
 }
 
-static int snapshot_id_add(snapshot_id_list *s, u32 id)
-{
-	BUG_ON(snapshot_list_has_id(s, id));
-
-	return darray_push(s, id);
-}
-
 static int bch2_snapshot_delete_keys_btree(struct btree_trans *trans,
 					   snapshot_id_list *deleted,
 					   enum btree_id btree_id)
@@ -617,7 +610,7 @@ static int bch2_snapshot_delete_keys_btree(struct btree_trans *trans,
 			if (ret)
 				break;
 		} else {
-			ret = snapshot_id_add(&equiv_seen, equiv);
+			ret = snapshot_list_add(c, &equiv_seen, equiv);
 			if (ret)
 				break;
 		}
@@ -693,7 +686,7 @@ static void bch2_delete_dead_snapshots_work(struct work_struct *work)
 
 		snap = bkey_s_c_to_snapshot(k);
 		if (BCH_SNAPSHOT_DELETED(snap.v)) {
-			ret = snapshot_id_add(&deleted, k.k->p.offset);
+			ret = snapshot_list_add(c, &deleted, k.k->p.offset);
 			if (ret)
 				break;
 		}
@@ -921,7 +914,7 @@ int bch2_subvolume_wait_for_pagecache_and_delete_hook(struct btree_trans *trans,
 
 	mutex_lock(&c->snapshots_unlinked_lock);
 	if (!snapshot_list_has_id(&c->snapshots_unlinked, h->subvol))
-		ret = snapshot_id_add(&c->snapshots_unlinked, h->subvol);
+		ret = snapshot_list_add(c, &c->snapshots_unlinked, h->subvol);
 	mutex_unlock(&c->snapshots_unlinked_lock);
 
 	if (ret)

fs/bcachefs/subvolume.h

@@ -93,6 +93,27 @@ static inline bool snapshot_list_has_id(snapshot_id_list *s, u32 id)
 	return false;
 }
 
+static inline bool snapshot_list_has_ancestor(struct bch_fs *c, snapshot_id_list *s, u32 id)
+{
+	u32 *i;
+
+	darray_for_each(*s, i)
+		if (bch2_snapshot_is_ancestor(c, id, *i))
+			return true;
+	return false;
+}
+
+static inline int snapshot_list_add(struct bch_fs *c, snapshot_id_list *s, u32 id)
+{
+	int ret;
+
+	BUG_ON(snapshot_list_has_id(s, id));
+	ret = darray_push(s, id);
+	if (ret)
+		bch_err(c, "error reallocating snapshot_id_list (size %zu)", s->size);
+	return ret;
+}
+
 int bch2_fs_snapshots_check(struct bch_fs *);
 void bch2_fs_snapshots_exit(struct bch_fs *);
 int bch2_fs_snapshots_start(struct bch_fs *);