Re: [External] Re: [PATCH] fuse: add hang check in request_wait_answer()

[Zhang Tianci]

Hi Joanne，

> imo it's possible to check whether the kernel itself is affected just
> purely through libfuse changes to fuse_lowlevel.c where the request
> communication with the kernel happens. The number of requests ready by
> the kernel is exposed to userspace through sysfs, so if the daemon is
> deadlocked or cannot read fuse requests, that scenario is detectable
> by userspace.

Yes, checking in libfuse/fuse_lowlevel.c is feasible, but it depends on
the running state of FUSEDaemon(if FUSEDaemon is in a process exit state,
this check cannot be performed), I think we do need this approach,
but it cannot fully cover all scenarios. Therefore, I believe it
should coexist with this patch.

The content of the /sys/fs/fuse/connections/${devid}/waiting interface
is inaccurate;
it cannot distinguish between normal waiting and requests that have been hanging
for a period of time.

Thanks,
Tianci