From: Timo Sirainen <timo.sirainen@dovecot.fi>
Date: Mon, 19 Feb 2018 10:54:53 +0000 (+0200)
Subject: lib-storage: mailbox_list_index_handle_corruption() - Lock mailbox list while rebuilding
X-Git-Tag: 2.3.9~2247
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ccfccd9aaeb1e85d1796b845c72c3953f4867693;p=thirdparty%2Fdovecot%2Fcore.git

lib-storage: mailbox_list_index_handle_corruption() - Lock mailbox list while rebuilding

This guards against simultaneous mailbox create/delete/rename.
---

diff --git a/src/lib-storage/list/mailbox-list-index.c b/src/lib-storage/list/mailbox-list-index.c
index fec655418d..4326620bc3 100644
--- a/src/lib-storage/list/mailbox-list-index.c
+++ b/src/lib-storage/list/mailbox-list-index.c
@@ -625,7 +625,19 @@ int mailbox_list_index_handle_corruption(struct mailbox_list *list)
 	if (ilist->handling_corruption)
 		return 0;
 	ilist->handling_corruption = TRUE;
-	ret = list_handle_corruption_locked(list, reason);
+
+	/* Perform the rebuilding locked. Note that if we're here because
+	   INBOX wasn't found, this may be because another process is in the
+	   middle of creating it. Waiting for the lock here makes sure that
+	   we don't start rebuilding before it's finished. In that case the
+	   rebuild is a bit unnecessary, but harmless (and avoiding the rebuild
+	   just adds extra code complexity). */
+	if (mailbox_list_lock(list) < 0)
+		ret = -1;
+	else {
+		ret = list_handle_corruption_locked(list, reason);
+		mailbox_list_unlock(list);
+	}
 	ilist->handling_corruption = FALSE;
 	return ret;
 }