bcachefs: bch2_btree_root_alloc_fake_trans()

We're starting to be more strict about transaction locked state, and
multiple transactions in a task.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_gc.c

@@ -540,9 +540,9 @@ int bch2_check_topology(struct bch_fs *c)
 			if (!bch2_btree_has_scanned_nodes(c, i)) {
 				mustfix_fsck_err(c, btree_root_unreadable_and_scan_found_nothing,
 						 "no nodes found for btree %s, continue?", bch2_btree_id_str(i));
-				bch2_btree_root_alloc_fake(c, i, 0);
+				bch2_btree_root_alloc_fake_trans(trans, i, 0);
 			} else {
-				bch2_btree_root_alloc_fake(c, i, 1);
+				bch2_btree_root_alloc_fake_trans(trans, i, 1);
 				bch2_shoot_down_journal_keys(c, i, 1, BTREE_MAX_DEPTH, POS_MIN, SPOS_MAX);
 				ret = bch2_get_scanned_nodes(c, i, 0, POS_MIN, SPOS_MAX);
 				if (ret)
@@ -570,7 +570,7 @@ int bch2_check_topology(struct bch_fs *c)
 				goto reconstruct_root;
 
 			bch_err(c, "empty btree root %s", bch2_btree_id_str(i));
-			bch2_btree_root_alloc_fake(c, i, 0);
+			bch2_btree_root_alloc_fake_trans(trans, i, 0);
 			r->alive = false;
 			ret = 0;
 		}

fs/bcachefs/btree_update_interior.c

@@ -2513,7 +2513,7 @@ void bch2_btree_set_root_for_read(struct bch_fs *c, struct btree *b)
 	bch2_btree_set_root_inmem(c, b);
 }
 
-static int __bch2_btree_root_alloc_fake(struct btree_trans *trans, enum btree_id id, unsigned level)
+int bch2_btree_root_alloc_fake_trans(struct btree_trans *trans, enum btree_id id, unsigned level)
 {
 	struct bch_fs *c = trans->c;
 	struct closure cl;
@@ -2561,7 +2561,7 @@ static int __bch2_btree_root_alloc_fake(struct btree_trans *trans, enum btree_id
 
 void bch2_btree_root_alloc_fake(struct bch_fs *c, enum btree_id id, unsigned level)
 {
-	bch2_trans_run(c, __bch2_btree_root_alloc_fake(trans, id, level));
+	bch2_trans_run(c, bch2_btree_root_alloc_fake_trans(trans, id, level));
 }
 
 static void bch2_btree_update_to_text(struct printbuf *out, struct btree_update *as)

fs/bcachefs/btree_update_interior.h

@@ -175,6 +175,8 @@ int bch2_btree_node_update_key_get_iter(struct btree_trans *, struct btree *,
 					struct bkey_i *, unsigned, bool);
 
 void bch2_btree_set_root_for_read(struct bch_fs *, struct btree *);
+
+int bch2_btree_root_alloc_fake_trans(struct btree_trans *, enum btree_id, unsigned);
 void bch2_btree_root_alloc_fake(struct bch_fs *, enum btree_id, unsigned);
 
 static inline unsigned btree_update_reserve_required(struct bch_fs *c,