bcachefs: Kill bch2_path_put_nokeep()

bch2_path_put_nokeep() was intended for paths we wouldn't need to
preserve for a transaction restart - it always frees them right away
when the ref hits 0.

But since paths are shared, freeing unconditionally is a bug, the path
might have been used elsewhere and have should_be_locked set, i.e. we
need to keep it locked until the end of the transaction.

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

Author: Kent Overstreet

fs/bcachefs/btree_iter.c

@@ -1431,15 +1431,6 @@ void bch2_path_put(struct btree_trans *trans, btree_path_idx_t path_idx, bool in
 	__bch2_path_free(trans, path_idx);
 }
 
-static void bch2_path_put_nokeep(struct btree_trans *trans, btree_path_idx_t path,
-				 bool intent)
-{
-	if (!__btree_path_put(trans, trans->paths + path, intent))
-		return;
-
-	__bch2_path_free(trans, path);
-}
-
 void __noreturn bch2_trans_restart_error(struct btree_trans *trans, u32 restart_count)
 {
 	panic("trans->restart_count %u, should be %u, last restarted by %pS\n",
@@ -2358,8 +2349,7 @@ struct bkey_s_c bch2_btree_iter_peek_max(struct btree_trans *trans, struct btree
 	}
 
 	if (iter->update_path) {
-		bch2_path_put_nokeep(trans, iter->update_path,
-				     iter->flags & BTREE_ITER_intent);
+		bch2_path_put(trans, iter->update_path, iter->flags & BTREE_ITER_intent);
 		iter->update_path = 0;
 	}
 
@@ -2388,8 +2378,8 @@ struct bkey_s_c bch2_btree_iter_peek_max(struct btree_trans *trans, struct btree
 
 			if (iter->update_path &&
 			    !bkey_eq(trans->paths[iter->update_path].pos, k.k->p)) {
-				bch2_path_put_nokeep(trans, iter->update_path,
-						     iter->flags & BTREE_ITER_intent);
+				bch2_path_put(trans, iter->update_path,
+					      iter->flags & BTREE_ITER_intent);
 				iter->update_path = 0;
 			}
 
@@ -2648,7 +2638,7 @@ struct bkey_s_c bch2_btree_iter_peek_prev_min(struct btree_trans *trans, struct
 				 * the last possible snapshot overwrite, return
 				 * it:
 				 */
-				bch2_path_put_nokeep(trans, iter->path,
+				bch2_path_put(trans, iter->path,
 					      iter->flags & BTREE_ITER_intent);
 				iter->path = saved_path;
 				saved_path = 0;
@@ -2678,8 +2668,8 @@ struct bkey_s_c bch2_btree_iter_peek_prev_min(struct btree_trans *trans, struct
 				 * our previous saved candidate:
 				 */
 				if (saved_path) {
-					bch2_path_put_nokeep(trans, saved_path,
-					      iter->flags & BTREE_ITER_intent);
+					bch2_path_put(trans, saved_path,
+						      iter->flags & BTREE_ITER_intent);
 					saved_path = 0;
 				}
 
@@ -2722,7 +2712,7 @@ struct bkey_s_c bch2_btree_iter_peek_prev_min(struct btree_trans *trans, struct
 		iter->pos.snapshot = iter->snapshot;
 out_no_locked:
 	if (saved_path)
-		bch2_path_put_nokeep(trans, saved_path, iter->flags & BTREE_ITER_intent);
+		bch2_path_put(trans, saved_path, iter->flags & BTREE_ITER_intent);
 
 	bch2_btree_iter_verify_entry_exit(iter);
 	bch2_btree_iter_verify(trans, iter);
@@ -3045,7 +3035,7 @@ static inline void btree_path_list_add(struct btree_trans *trans,
 void bch2_trans_iter_exit(struct btree_trans *trans, struct btree_iter *iter)
 {
 	if (iter->update_path)
-		bch2_path_put_nokeep(trans, iter->update_path,
+		bch2_path_put(trans, iter->update_path,
 			      iter->flags & BTREE_ITER_intent);
 	if (iter->path)
 		bch2_path_put(trans, iter->path,