Re: fuse: when are release requests queued?

[Nikolaus Rath <Nikolaus@rath.org>]

On May 31 2017, Michael Theall <pigman46-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> I do not fully understand the difference you describe. What I would like
>> to construct is the following scenario:
>>
>> 1. Userspace calls close()
>> 2. Userspace close() returns
>> 3. Userspace calls unlink()
>> 4. Userspace unlink() returns
>> 5. libfuse reads UNLINK request from kernel pipe
>> 6. libfuse reads RELEASE request from kernel pipe
>>
>> What would be the simplest way to do that?
>>
> Won't unlink(2) block until the fuse server has responded?

Yes, you are right. It should be:

 1. Userspace calls close()
 2. Userspace close() returns
 3. Userspace calls unlink()
 4. libfuse reads UNLINK request from kernel pipe
 5. Userspace unlink() returns
 6. libfuse reads RELEASE request from kernel pipe

> I'm pretty sure
> the close(2) should come back after the fuse server responds to FLUSH. It
> sounds like with your RELEASE delay in the kernel, you should get your
> steps as described buy step 4 and 5 must be swapped.

No, the delay comes in between (1) and (2).

Best,
-Nikolaus

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