virtiofs: drop writeback option

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 <f.ebner@proxmox.com>
This commit is contained in:
Fiona Ebner 2025-04-08 17:07:14 +02:00 committed by Thomas Lamprecht
parent dfdd5c3689
commit d2d8a15dea

View File

@ -45,13 +45,6 @@ my $virtiofs_fmt = {
default => 0,
optional => 1,
},
writeback => {
type => 'boolean',
description => "Enable writeback cache. If enabled, writes may be cached in the guest until"
." the file is closed or an fsync is performed.",
default => 0,
optional => 1,
},
'expose-xattr' => {
type => 'boolean',
description => "Enable support for extended attributes for this mount.",
@ -182,7 +175,6 @@ sub start_virtiofsd {
push @$cmd, '--announce-submounts';
push @$cmd, '--allow-direct-io' if $virtiofs->{'direct-io'};
push @$cmd, '--cache='.$virtiofs->{cache} if $virtiofs->{cache};
push @$cmd, '--writeback' if $virtiofs->{'writeback'};
push @$cmd, '--syslog';
exec(@$cmd);
} elsif (!defined($pid2)) {