Re: [PATCH 1/2] conf: add locking option to disk source

On Wed, Feb 14, 2024 at 14:17:57 +0900, Hiroki Narukawa wrote: > There is a case that locking hits a bug and users wants to disable > locking like bug in Linux kernel. > > This commit adds option to configure locking for file source. > > Signed-off-by: Hiroki Narukawa <hnarukaw(a)yahoo-corp.jp&gt; > --- > docs/formatdomain.rst | 5 +++++ > src/conf/domain_conf.c | 8 ++++++++ > src/conf/schemas/domaincommon.rng | 5 +++++ > src/conf/storage_source_conf.h | 3 +++ > 4 files changed, 21 insertions(+) > > diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst > index 0a4f9d9000..95869d573c 100644 > --- a/docs/formatdomain.rst > +++ b/docs/formatdomain.rst > @@ -2782,6 +2782,11 @@ paravirtualized driver is specified via the ``disk`` element. > via the filesystem. The filename passed via ``file`` can still be used > to generate paths to write into image metadata when doing block operations > but libvirt will not access these natively. > + > + :since:`Since 10.1.0` a new optional attribute ``locking`` can be added > + which can take "on" or "off". Basically this option should be kept > + default, but it can be used explicitly for workaround about bug in > + locking. This is not the first time this is being suggested and I'm still not persuaded that we want this. We definitelly do not want this as a generic production attribute. A possibility would be to do it as part of the qemu XML namespace along with tainting the VM that such config is being used. https://libvirt.org/drvqemu.html#pass-through-of-arbitrary-qemu-commands The main reason is that you never actually want to use this, except for the very specific case of bugs you are mentioning.