From: Stefan Reiter <s.reiter@proxmox.com>
Date: Wed, 30 Jun 2021 15:18:17 +0000 (+0200)
Subject: cfg2cmd/drive: don't use io_uring for krbd with wb/wt cache
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=628937f53acde52f7257ca79f574c87a45f392e7;p=qemu-server.git

cfg2cmd/drive: don't use io_uring for krbd with wb/wt cache

As reported here and locally reproduced:
https://forum.proxmox.com/threads/efi-vms-wont-start-under-7-beta-with-writeback-cache.91629/

This configuration is currently broken. Until we figure out how to fix
it properly, we can just have this (luckily very narrow) config pattern
fall back to aio=threads as it used to.

Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
---

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 8af41765..f7604674 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -1600,8 +1600,11 @@ sub print_drive_commandline_full {
 	$cache_direct = 1;
     }
 
+    # io_uring with cache mode writeback or writethrough on krbd will hang...
+    my $rbd_no_io_uring = $scfg && $scfg->{type} eq 'rbd' && $scfg->{krbd} && !$cache_direct;
+
     if (!$drive->{aio}) {
-	if ($io_uring) {
+	if ($io_uring && !$rbd_no_io_uring) {
 	    # io_uring supports all cache modes
 	    $opts .= ",aio=io_uring";
 	} else {