bcachefs: __bch2_insert_snapshot_whiteouts() refactoring

Now uses bch2_get_snapshot_overwrites(), and much shorter.

Signed-off-by: Kent Overstreet <[email protected]>

Author: Kent Overstreet

fs/bcachefs/btree_update.c

@@ -123,76 +123,44 @@ static int need_whiteout_for_snapshot(struct btree_trans *trans,
 }
 
 int __bch2_insert_snapshot_whiteouts(struct btree_trans *trans,
-				   enum btree_id id,
-				   struct bpos old_pos,
-				   struct bpos new_pos)
+				     enum btree_id btree, struct bpos pos,
+				     snapshot_id_list *s)
 {
-	struct bch_fs *c = trans->c;
-	struct btree_iter old_iter, new_iter = {};
-	struct bkey_s_c old_k, new_k;
-	snapshot_id_list s;
-	struct bkey_i *update;
 	int ret = 0;
 
-	if (!bch2_snapshot_has_children(c, old_pos.snapshot))
-		return 0;
-
-	darray_init(&s);
+	darray_for_each(*s, id) {
+		pos.snapshot = *id;
 
-	bch2_trans_iter_init(trans, &old_iter, id, old_pos,
-			     BTREE_ITER_not_extents|
-			     BTREE_ITER_all_snapshots);
-	while ((old_k = bch2_btree_iter_prev(trans, &old_iter)).k &&
-	       !(ret = bkey_err(old_k)) &&
-	       bkey_eq(old_pos, old_k.k->p)) {
-		struct bpos whiteout_pos =
-			SPOS(new_pos.inode, new_pos.offset, old_k.k->p.snapshot);
-
-		if (!bch2_snapshot_is_ancestor(c, old_k.k->p.snapshot, old_pos.snapshot) ||
-		    snapshot_list_has_ancestor(c, &s, old_k.k->p.snapshot))
-			continue;
-
-		new_k = bch2_bkey_get_iter(trans, &new_iter, id, whiteout_pos,
-					   BTREE_ITER_not_extents|
-					   BTREE_ITER_intent);
-		ret = bkey_err(new_k);
+		struct btree_iter iter;
+		struct bkey_s_c k = bch2_bkey_get_iter(trans, &iter, btree, pos,
+						       BTREE_ITER_not_extents|
+						       BTREE_ITER_intent);
+		ret = bkey_err(k);
 		if (ret)
 			break;
 
-		if (new_k.k->type == KEY_TYPE_deleted) {
-			update = bch2_trans_kmalloc(trans, sizeof(struct bkey_i));
+		if (k.k->type == KEY_TYPE_deleted) {
+			struct bkey_i *update = bch2_trans_kmalloc(trans, sizeof(struct bkey_i));
 			ret = PTR_ERR_OR_ZERO(update);
-			if (ret)
+			if (ret) {
+				bch2_trans_iter_exit(trans, &iter);
 				break;
+			}
 
 			bkey_init(&update->k);
-			update->k.p		= whiteout_pos;
+			update->k.p		= pos;
 			update->k.type		= KEY_TYPE_whiteout;
 
-			ret = bch2_trans_update(trans, &new_iter, update,
+			ret = bch2_trans_update(trans, &iter, update,
 						BTREE_UPDATE_internal_snapshot_node);
 		}
-		bch2_trans_iter_exit(trans, &new_iter);
+		bch2_trans_iter_exit(trans, &iter);
 
-		ret = snapshot_list_add(c, &s, old_k.k->p.snapshot);
 		if (ret)
 			break;
 	}
-	bch2_trans_iter_exit(trans, &new_iter);
-	bch2_trans_iter_exit(trans, &old_iter);
-
-	snapshot_id_list s2;
-	ret = bch2_get_snapshot_overwrites(trans, id, old_pos, &s2);
-	if (ret) {
-		darray_exit(&s);
-		return ret;
-	}
-
-	BUG_ON(s.nr != s2.nr);
-	BUG_ON(memcmp(s.data, s2.data, sizeof(s.data[0]) * s.nr));
 
-	darray_exit(&s2);
-	darray_exit(&s);
+	darray_exit(s);
 	return ret;
 }
 

fs/bcachefs/btree_update.h

@@ -4,6 +4,7 @@
 
 #include "btree_iter.h"
 #include "journal.h"
+#include "snapshot.h"
 
 struct bch_fs;
 struct btree;
@@ -74,7 +75,7 @@ static inline int bch2_btree_delete_at_buffered(struct btree_trans *trans,
 }
 
 int __bch2_insert_snapshot_whiteouts(struct btree_trans *, enum btree_id,
-				     struct bpos, struct bpos);
+				     struct bpos, snapshot_id_list *);
 
 /*
  * For use when splitting extents in existing snapshots:
@@ -88,11 +89,20 @@ static inline int bch2_insert_snapshot_whiteouts(struct btree_trans *trans,
 						 struct bpos old_pos,
 						 struct bpos new_pos)
 {
+	BUG_ON(old_pos.snapshot != new_pos.snapshot);
+
 	if (!btree_type_has_snapshots(btree) ||
 	    bkey_eq(old_pos, new_pos))
 		return 0;
 
-	return __bch2_insert_snapshot_whiteouts(trans, btree, old_pos, new_pos);
+	snapshot_id_list s;
+	int ret = bch2_get_snapshot_overwrites(trans, btree, old_pos, &s);
+	if (ret)
+		return ret;
+
+	return s.nr
+		? __bch2_insert_snapshot_whiteouts(trans, btree, new_pos, &s)
+		: 0;
 }
 
 int bch2_trans_update_extent_overwrite(struct btree_trans *, struct btree_iter *,