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Date: Tue, 5 Jun 2018 14:10:24 +0200
From: David Sterba <dsterba@suse.cz>
To: Andreas Gruenbacher <agruenba@redhat.com>
Cc: cluster-devel@redhat.com, Christoph Hellwig <hch@lst.de>,
        linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v8 03/10] iomap: Complete partial direct I/O writes
 synchronously
Message-ID: <20180605121024.t6indzioavvfonxk@twin.jikos.cz>
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References: <20180604193123.27655-1-agruenba@redhat.com>
 <20180604193123.27655-4-agruenba@redhat.com>
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On Mon, Jun 04, 2018 at 09:31:16PM +0200, Andreas Gruenbacher wrote:
> @@ -1062,8 +1063,9 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
>  	if (ret < 0)
>  		iomap_dio_set_error(dio, ret);
>  
> +	smp_mb__before_atomic();
>  	if (!atomic_dec_and_test(&dio->ref)) {

The barrier should be documented. I tried to do a quick look around the
code if it's clear why it's there but it's not. Thanks.

> -		if (!is_sync_kiocb(iocb))
> +		if (!dio->wait_for_completion)
>  			return -EIOCBQUEUED;
>  
>  		for (;;) {