Re: [PATCH] file-posix: detect the lock using the real file

[Li Feng]

Kevin Wolf <kwolf@redhat.com> 于2020年12月8日周二 下午10:38写道：
>
> Am 08.12.2020 um 13:59 hat Li Feng geschrieben:
> > This patch addresses this issue:
> > When accessing a volume on an NFS filesystem without supporting the file 
> > lock,
> > tools, like qemu-img, will complain "Failed to lock byte 100".
> >
> > In the original code, the qemu_has_ofd_lock will test the lock on the
> > "/dev/null" pseudo-file. Actually, the file.locking is per-drive property,
> > which depends on the underlay filesystem.
> >
> > In this patch, make the 'qemu_has_ofd_lock' with a filename be more generic
> > and reasonable.
> >
> > Signed-off-by: Li Feng <fengli@smartx.com>
>
> Do you know any way how I could configure either the NFS server or the
> NFS client such that locking would fail? For any patch related to this,
> it would be good if I could even test the scenario.
>
Hi Kevin, currently our SmartX ZBS storage NFS server doesn't support
the file lock and the lock operation will return failure.
I have tried the kernel NFS server, and it works well. I don't have more kinds
of NFS servers.

> For this specific patch, I think Daniel has already provided a good
> explanation of the fundamental problems it has.
>
> Kevin
>