Re: [PATCH v2 19/19] sunrpc: Disable splice for krb5i

Chuck Lever
2017-06-19T15:22:41Z

> On Jun 18, 2017, at 3:34 AM, Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> wrote:
>
> On Sat, Jun 17, 2017 at 01:23:24PM -0400, Chuck Lever wrote:
>>
>>> On Jun 17, 2017, at 11:07 AM, Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> wrote:
>>>
>>> On Fri, Jun 16, 2017 at 11:22:54AM -0400, Chuck Lever wrote:
>>>> Running a multi-threaded 8KB fio test (70/30 mix), three or four out
>>>> of twelve of the jobs fail when using krb5i. The failure is an EIO
>>>> on a read.
>>>
>>> Just curious: what is the backing fs that you tested with? I'd be
>>> curious if you see this on XFS for example.
>>
>> I was able to reproduce this with a tmpfs share and
>> with an XFS share on NVMe LUNs.
>
> Interesting. XFS actually locks out all writes while doing a buffered
> read, so we end up with two different read instance for the hash vs
> the data, which does indeed sound dangerous.

I'm going to submit this again with a comment change and
Jeff's Reviewed-by. Can I add your Reviewed-by as well?

--
Chuck Lever

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