From 23123df035436cf2a8cb4ee672f439ce13539ea8 Mon Sep 17 00:00:00 2001 From: Fiona Ebner Date: Tue, 8 Apr 2025 17:07:15 +0200 Subject: [PATCH] qm: virtiofs: drop writeback cache VirtIO-fs using writeback cache seems very broken at the moment. If a guest accesses a file (even just using 'touch'), that the host is currently writing, the guest can permanently end up with a truncated version of that file. Even subsequent operations like moving the file, will not result in the correct file being visible, but just rename the truncated one. Signed-off-by: Fiona Ebner --- qm.adoc | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/qm.adoc b/qm.adoc index f17cee9..39cf492 100644 --- a/qm.adoc +++ b/qm.adoc @@ -1309,7 +1309,7 @@ has been configured in the resource mapping. Additionally, you can set the `cache` option to either `always`, `never`, `metadata`, or `auto` (default: `auto`), depending on your requirements. How the different caching modes behave can be read https://lwn.net/Articles/774495/[here under the "Caching Modes" -section]. To enable writeback cache set `writeback` to `1`. +section]. The `virtiofsd` supports ACL and xattr passthrough (can be enabled with the `expose-acl` and `expose-xattr` options), allowing the guest to access ACLs and @@ -1327,7 +1327,7 @@ applications do their own caching. ---- qm set -virtiofs0 dirid=,cache=always,direct-io=1 qm set -virtiofs1 ,cache=never,expose-xattr=1 -qm set -virtiofs2 ,expose-acl=1,writeback=1 +qm set -virtiofs2 ,expose-acl=1 ---- To temporarily mount virtiofs in a guest VM with the Linux kernel virtiofs