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Date:   Wed, 5 Sep 2018 09:53:36 -0400
From:   "J. Bruce Fields" <bfields@fieldses.org>
To:     Jeff Layton <jlayton@redhat.com>
Cc:     =?utf-8?B?54Sm5pmT5Yas?= <milestonejxd@gmail.com>,
        R.E.Wolff@bitwizard.nl, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: POSIX violation by writeback error
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On Wed, Sep 05, 2018 at 06:55:15AM -0400, Jeff Layton wrote:
> There is no requirement for a filesystem to flush data on close(). In
> fact, most local filesystems do not. NFS does, but that's because it has
> to in order to provide close-to-open cache consistency semantics.

And these days even NFS can delay writeback till after close thanks to
write delegations.

--b.