[PING] Avoid excessive buffer size in libio

[Florian Weimer]

On 06/24/2016 05:35 PM, Florian Weimer wrote:
> On 05/19/2016 04:57 PM, Florian Weimer wrote:
>> On 03/31/2016 12:14 PM, Florian Weimer wrote:
>>> On 03/18/2016 11:52 PM, Roland McGrath wrote:
>>>
>>>> Whatever the results, they would not IMHO be relevant here.
>>>>
>>>> POSIX specifies that st_blksize is the "preferred I/O block size for
>>>> this
>>>> object".  It's the kernel's responsibility to give userland good advice
>>>> through this channel.  If there are common buggy kernels that give bad
>>>> advice, that is a reason to apply upper and lower limits to the
>>>> advice from
>>>> the kernel.  But the expectation should be that the kernel gets
>>>> fixed to
>>>> give good advice, and the optimal thing to do with a good kernel is to
>>>> follow its advice.
>>>>
>>>> Since the recommended use of st_blksize in this way is a standard user
>>>> feature and not just what stdio's implementation happens to do, there
>>>> is an
>>>> argument to be made that the limiting of the value should be done in
>>>> the
>>>> *stat functions reported st_blksize values rather than in stdio's
>>>> use of
>>>> them.  (I'm ambivalent about this point.)
>>>
>>> That's a good point.  I'll try to get feedback from kernel file system
>>> developers on this matter.
>>
>> I wasn't able to get any feedback.  Based on Rich's point about random
>> I/O and Roland's earlier suggestion, I'm just capping the reported
>> buffer size to 8192 in the attached patch.
>
> Ping?
>
>   <https://sourceware.org/ml/libc-alpha/2016-05/msg00428.html>

Ping?

Thanks,
Florian