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

[Kevin Wolf]

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.

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

Kevin