From: Goldwyn Rodrigues <rgoldwyn@suse.de>
Subject: Re: [PATCH 0/10 v11] No wait AIO
Date: Mon, 12 Jun 2017 17:38:13 -0500
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Cc: akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org,
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To: Al Viro <viro@ZenIV.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>
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On 06/10/2017 12:34 AM, Al Viro wrote:
> On Thu, Jun 08, 2017 at 12:39:10AM -0700, Christoph Hellwig wrote:
>> As already indicated this whole series looks fine to me.
>>
>> Al: are you going to pick this up?  Or Andrew?
> 
> The main issue here is "let's bail out from ->write_iter() instances"
> patch.  It very obviously has holes in coverage.
> 
> Could we have FMODE_AIO_NOWAIT and make those who claim to support it
> set that in ->open()?  And make aio check that and bail out if asked
> for nowait on a file without that flag...
> 

Yes, I would agree.

We had FS_NOWAIT in filesystem type flags (in v3), but retracted it
later in v4.

Another option could be to keep the feature against FS_REQUIRES_DEV to
rule out filesystems which are not local, but it again has the problem
of holes in coverage.

I will work on adding FMODE_AIO_NOWAIT in the meantime.

Thanks,

-- 
Goldwyn