LAYOUT=index: Fixed error handling in mailbox creation race condition.

If two processes create the same mailbox, the other one ends up being
deleted on failure. However, if the deletion itself also failed the state
becomes a big ambiguous. We don't want to return MAIL_ERROR_EXISTS in that
case, because the caller may try to open the mailbox with the inconsistent
state and fail. So we'll instead return the original mailbox_delete() error
to the caller.

diff --git a/src/lib-storage/list/mailbox-list-index-backend.c b/src/lib-storage/list/mailbox-list-index-backend.c
index 2bf45ef28d65e7b0bcb834aeac59530a8caf135c..74d7ee503610708bc7bb7545759adafa6524b1aa 100644 (file)
--- a/src/lib-storage/list/mailbox-list-index-backend.c
+++ b/src/lib-storage/list/mailbox-list-index-backend.c
@@ -374,7 +374,8 @@ index_list_mailbox_create(struct mailbox *box,
                        if (ret <= 0) {
                                /* failed to add to list. rollback the backend
                                   mailbox creation */
-                               (void)mailbox_delete(box);
+                               if (mailbox_delete(box) < 0)
+                                       ret = -1;
                        }
                }
                list->create_mailbox_name = old_name;